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压力 肌 動 圖 Living Systems Instrumentation
[ 作者:佚名 | 来源:本站原创 | 点击数:4174 | 更新时间:2006-10-26  ]
压力 肌 動 圖 Living Systems Instrumentation 
 
 
       压力肌动图适用于研究微小动脉(内经>50微米)腔内的压力与直径的变化关系。实验在显微镜下进行,血管内径、外径、管腔内流量、压力和温度的改变通过计算机控制的图像分析系统实时连续的显示和记录下来。传感器连读地监测流入端和流出端的压力,水平张力可在微调控器下调节。血管腔内的压力可被压力调控器容易地调节。实验小室内的温度在温度控制装置的调控下保持恒温。实验小室的盖板上附有试液灌流装置、置换液体装置和气体供给装置。  Pressure Myograph System 200911.pdf
 
至1989年原创以来, 采用 Living Systems 压力肌动图进行血管生理及药理研究的全世界顶尖的研究机构和大学及药厂研究室已达余家。 生命科学实验研究发表的科学论文2008年已达五百多篇。
 
压力肌動圖系統包括以下几個部分:
 
肌动图系统:实验小室,中央控制及其信息转换装置,实验小室盖板,校准装置及其负压活舌。
压力调控系统:压力调控器:0 - 250 mmHg
数椐获取及其分析系统:倒置显徽镜、 C-接口、CCD摄像机,图像摄取I/O装置,计算机及其数椐获取/分析软件系统。
 
應用范圍:
基本特性: 小血管, 大血管, 血管壁厚度的測量,兩個血管的對比研究,不同种類的動物血管對比研究及其同類動物不同血管的對比研究,對局部血管反應性的評估, 人體不同血管的研究 .
血管反應机理的研究: 血管內皮:血管內皮分泌的舒張因子(一氧化氮), 前列腺素以及血管內皮分泌的超极化因子 ;
平滑肌:  鈣通道、鉀通道的作用机理
受體研究:  受體定位和作用特征研究, 激素,神經遞質及其它激動劑的影響 
药物机理的研究 :  ACE一抑制劑, 洋地黃及其胰島素作用机理的研究
生理學研究 :  年齡, 怀孕, 麻醉 ;
病理學研究:   高血壓, 脂肪沈滯性動脈硬化症, 糖尿病, 缺血症, 腫瘤, 心臟病,  肺疾病;
深入研究的可能性: 電生理實驗(膜電位的測定),  細胞內离子和其它物質的螢光測定
密封的、单血管室:CH/1/AU       CH/1/AU/SH
 
应用:1. 长期血管灌注        2. 血管培养      3. 基因转移        4. 重塑研究         5. 血管外压迫

压力控制和流量控制PS/200型:
压力模式:建立并自动维持0-200mmHg之间的所选压力
流动模式:产生可调节的、稳定的灌注速度,范围为3 µl/min2.5 ml/min。其压力传感器,可检测并控制微型蠕动泵的压力。
Extravascular Pressure Control System
 
最新产品: 血管外压力肌动图
即将血管压力(EvP)应用于安装在密封室中的离体插管的和有压力的血管 特别对心肌、骨骼肌和受到肌肉组织持续不变、脉动压力的血管(血管是嵌入肌肉组织中的), 对这些血管可进行研究,以测量经常发生的功能变化在心血管疾病中的意义,并分析潜在的机理。
1. EV-1型血管外压力控制器和SG-1型信号发生器。简单地说,当单独应用时,EV-1型产生可选择的、持续不变的EvP,起中间环节的作用,允许SG-1产生正弦的、脉动的血管外压力波形。  
2. CH/1/AU型密封血管室及其自加热姊妹型即CH/1/AU/SH型,是本系统的关键部件。
 
系统压力的基本来源,是一个实验室压缩气缸和一个调节(用户提供),使压力降低至6-8psi
然后,此压力由经过电子饲服阀从EV-1接收到的信号调节,产生所需要的稳定的或不稳定的血管外室压力。 饲服阀是EV-1的一个部件。
 
Function – The instruments provide a means for applying extravascular pressures (EvP) to excised, cannulated and pressurized vessels mounted in a sealed chamber. In particular, for cardiac, skeletal muscle and other vessels subjected to sustained or pulsatile pressures from the muscular tissue in which they are embedded. Studies can be carried out on these vessels to determine whether the functional changes that often occur may have local or distal significance in cardiovascular disease, and for analyzing underlying mechanisms.
System Components – The two instruments explained in more detail below are the Extravascular Pressure Control, Model EV-1 and the Signal Generator, Model SG-1. Briefly, the EV-1 produces selectable, sustained EvP when used alone, and acts as an intermediate link allowing the SG-1 to create sinusoidal and pulsatile extravascular pressure waveshapes.
          The sealed vessel chambers, Model CH/1/AU or its self-heated cousin Model CH/1/AU/SH are key components of this system. These chambers are described elsewhere on our website.
          A laboratory compressed gas tank and a regulating valve (user supplied) for reducing the pressure to 6 to 8 psi is the fundamental source of system pressure. It is then modified by signals received from the EV-1 via the Electronic Servo Valve to create the desired steady or non-steady extravascular chamber pressures. The servo valve is included as part of the EV-1.
  
EV – 1 Pressure Control Unit –
           The extravascular pressure (EvP) in the sealed chamber is sensed by a solid-state pressure transducer. The signal from this transducer is connected to the EV-1 Control Unit where it is compared with either the internal pressure signal set by the EV-1 pressure dial, or one of the external pressure signals fed into either the Function Generator or Signal Generator input jacks. Any difference between these two signals regulates the Electronic Servo Valve output pressure so that the two presures are the same.
Internal Pressure Signal Mode:  Here, the signal corresponding to the Pressure Dial setting calibrated in mmHg establishes the extravascular chamber pressure. This pressure is sustained until a new presure is selected. The panel meter reading also shows the chosen extravascular pressure in mmHg which can be accessed for data acquisition at the rear panel Pressure Signal jack.
External Pressure Signal Mode: When switched to this mode, various  extravascular pressure waveshapes can be created to match external input signals. Again, the actual extravascular pressure can be accessed for data acquisition at the rear panel Pressure Signal jack.
 Function Generator signals can be obtained from a computer program written by the user and a computer having a D/A computer board that supplies analog voltages of 10 mV/mmHg. In this way, various simple or complex, time-dependent pressures can be applied to the chamber.
Signal Generator – The Model SG-1 is used to establish sinusoidal and pulsatile extravascular waveshapes as described ahead.

EV-1 Specifications
Pressure Range:             0 – 250 mmHg
Pressure Output Signal: 10 mV/mmHg
External Input Signal:    10 mV/mmHg
Power:                            100-120 VAC/60 Hz or 200-240VAC/50Hz
Size/Weight:                  13 x 11 x 36 cm (H x W x L)/3.1 kg
    
Applications

Over 420 papers have been published using Living System Instrumentation's cannulated blood vessel system. We have compiled a bibliography, which may be accessed by clicking Bibliography.  Available in Adobe Acrobat for search use.

 A Host of Applications using these tools are at the disposal of the research investigator interested in obtaining new insights into the mechanisms of vascular function in human health and disease.

Typical Examples -

Studies: hypertension, diabetes, aging, and pregnancy

Tissue Sources: humans, primates, swine, rats, dogs, and rabbits

Vascular Beds: cerebral, coronary, lung, skin, and kidney

Vasoactive Agents: NO, endothelin, estrogen, peptides, and oxygen

Simultaneous Measurements: Fluorescence & Vessel Diameter

 

 

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Changes in diameter of rat gracilis arterioles as a function of perfusate flow

From: Koller A, Sun D, Huang A, Kaley G

Co-release of nitric oxide and prostaglandins mediates flow-dependent dilation of gracilis muscle arterioles. Am J Physiol 1994; 267:H326-H33

 

{short description of image}

Depolarization and constriction of rat myogenic cerebral arteries with tone by the KCA channel inhibitor iberiotoxin

From: Nelson MT , Cheng H, Rubart M, Santana LF, Bonev AD, Knot HJ, Lederer WJ

Relaxation of arterial smooth muscle by calcium sparks. Science 1995;270:633-637

Pressure = 60 mmHg


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Coronary microvessel responses of normal and atherosclerotic monkeys to acetylcholine

Vessel diameters = 122 - 220 µm

From: Sellke FW, Armstrong ML, Harrison DG

Endothelium-dependent vascular relaxation is abnormal in the coronary microcirculation of atherosclerotic primates. Circ 1990;81:1586-1593

 

{short description of image}

Spontaneous vasomotion of cerebral artery diameter as a function of temperature

Pressure = 80 mmHg

From: Osol G, Halpern W

Spontaneous vasomotion in pressurized cerebral arteries from genetically hypertensive rats. Am J Physiol 1988;254 (Heart Circ Physiol 23):H28-H33


{short description of image}

Oxygen reactivity of an isolated rat cremaster muscle arteriole

Pressure = 65 mmHg; ID = 77 µm

From: Messina EJ, Sun D, Koller A, Wolin MS, Kaley G

Increases in oxygen tension evoke arteriolar constriction by inhibiting endothelial prostaglandin synthesis. Microvasc Res 1994;48(2):151-160

Quick Summary
Single & Dual Vessel Chamber Models
For Perfusion of Isolated, Cannulated Vessels
    These chambers are machined from an inert plastic (PET) that has chemical and physical properties superior to acrylics. The chambers can be readily mounted on the microscope mechanical stage for adjustment of the image field.
Single Vessel Chambers- Most can be supplied with Pt stimulation electrodes for electrical neurotransmitter release from the nerve varicosities. Add /S to model number for this option. All of these chambers are ideal for applications requiring confocal microscopy and simultaneous fluorescence and diameter measurements.  For ratiometric fluorescence and vessel dimensioning data acquisition systems, consider IonOptix www.ionoptix.com.
 Picture
Model  Description
CH/1/AU
Sealed chamber for applying extravascular pressures to a perfused, pressurized vessel and for long-term perfusion experiments.  Bath volume: 3-5 ml. Requires superfusion for warming bath.
CH/1/AU/SH
Similar to CH/1/AU, but includes Self-Heated bath and temperature controller.  May be used with or without superfusion.
CH/1
For fluorescent, confocal, and many other applications. Requires superfusion for warming bath.
CH/1/SH
Same as CH/1 but includes Self-Heated bath and temperature controller. May be used with or without superfusion.
CH/1/QT
For rapid freezing or fixation of cannulated, pressurized vessel
CH/1/R
For axially rotating or inverting a cannulated, pressurized vessel.
 
Dual Vessel Chambers - Most can be supplied with Pt stimulation electrodes for electrical neurotransmitter release from the nerve varicosities. Add /S to model number for this option. 
 Picture
Model  Description
CH/2/A
Separate baths; 8 ml bath volume; requires superfusion for warming bath.
CH/2/E
Separate baths; 8 ml bath volume; removable cover for control of gas environment above baths; requires superfusion for warming bath.
CH/2/SH
Separate baths; 2 ml bath volume; Self-Heated baths and temperature controller; non-superfused baths.
 
Pressure
Control and Measurement
Model PS/200
This Pressure Servo and Peristaltic Pump instrument has two modes of operation.
Pressure mode - Establishes and automatically maintains any selected pressure between 0 and 200 mmHg.
Flow mode - Produces an adjustable, stable perfusion rate in the range of 3 µl/min to 2.5 ml/min.
A solid-state pressure transducer placed in a biological preparation setup, such as a cannulated vessel, senses the pressure for control of the miniature peristaltic pump. This pump supplies physiological perfusates from a reservoir to generate and hold a particular pressure, or flow; each can be independently determined by the setting of pre-calibrated dials. Pressure is indicated directly in mmHg on a digital panel meter in both modes, and is available as an analog output voltage for data acquisition. Pressure may also be programmed through an external voltage signal applied to the instrument. Additional information can be found in Q&A.
Model PS/20
This instrument is similar to the PS/200 except that the maximum pressure range is 20 mmHg. It is especially useful for low pressure vessel experiments on veins, airways and lymphatics.
 
Features
  • Linear calibration of pressure and flow signals
  • Flow-thru pressure transducers · Pressure or flow values easily changed
  • Pump can be positioned relatively near to the vessel chamber to minimize perfusion time
Applications
  • Maintain transmural pressure during flow changes
  • Examine myogenic responses
  • Deliver vasoactive agents intralumenally
  • Determine concentration/response relationships
  • Collect perfusate for biochemical analysis
  • Regulate distal flow resistance
 
Specifications of the PS/200 and PS/20 instruments
Model PS/200 PS/20
Pressure Range 0 - 200 mmHg 0 - 20 mmHg0 - 20 mmHg
Panel Meter Reading ± 1 mmHg ± 0.1 mmHg
Pressure Signal Output 10 mV/mmHg 10 mV/mmHg
External Input Signal 1 V for 100 mmHg 200 mV for 20 mmHg
Power Supply
100 - 120 V/60 Hz or 200 - 240 V/50 Hz (13 W)
Perfusion Flow Rate
3 µl/min - 2.5 ml/min
Size/Weight
Control Unit: 13x11x36 cm/2.3 kg
Pump Unit: 13x11x15 cm/0.9 kg


Perfusion Pressure Monitor
Measure and Record -
  • Two Pressures
    • Pressure Difference
      • Pressure Average
Model PM/4
This instrument is ideally suited for isolated, perfused vessel studies to aid the investigator in ensuring that a perfused vessel is exposed to a desired physiological pressure. It can also be used for measuring the pressures at two locations in a vessel bed or isolated tissue. In conjunction with the Pressure Servo and Peristaltic Pump, PS/200 or PS/20, a transmural vessel pressure or a perfusion pressure may automatically be maintained during perfusion.
Features
  • Pressure Range: 0 - 200 mmHg
  • Digital Readout of Selected Pressures: ± 1 mmHg
  • Four Pressure Signal Outputs: 10 mV/mmHg
  • Linearity: ± 1 mmHg
  • Two solid state flow-thru transducers
A simple procedure is used to calibrate the four pressure signals directly in mmHg. These pressure signals can be simultaneously sent to a recorder or data acquisition system while selectively monitoring any one of the four pressures on the meter. Two pressure transducers with Luer fittings and output cables for the four signals are supplied with the instrument. Also, see Q&A.
Specifications
  • Digital Meter: 0 - 200 mmHg; 1 mmHg resolution; ± 1% linearity; 3 samples/s
  • Analog Outputs: 10 mV/mmHg; 0 - 300 mmHg; <15 ms response time; ± 1% linearity
  • Pressure Transducers: 0.04 mm3/100mmHg volume displacement
  • Size: 6.5 x 14.5 x 17.5cm (H x W x L); Weight: 0.3 kg ·
  • Power: 100 -120 V/60Hz or 200 - 240 V/50Hz

Extravascular Pressure Control System
 
最新产品: 血管外压力肌动图
即将血管压力(EvP)应用于安装在密封室中的离体插管的和有压力的血管 特别对心肌、骨骼肌和受到肌肉组织持续不变、脉动压力的血管(血管是嵌入肌肉组织中的), 对这些血管可进行研究,以测量经常发生的功能变化在心血管疾病中的意义,并分析潜在的机理。
1. EV-1型血管外压力控制器和SG-1型信号发生器。简单地说,当单独应用时,EV-1型产生可选择的、持续不变的EvP,起中间环节的作用,允许SG-1产生正弦的、脉动的血管外压力波形。  
2. CH/1/AU型密封血管室及其自加热姊妹型即, CH/1/AU/SH型,是本系统的关键部件。
Function – The instruments provide a means for applying extravascular pressures (EvP) to excised, cannulated and pressurized vessels mounted in a sealed chamber. In particular, for cardiac, skeletal muscle and other vessels subjected to sustained or pulsatile pressures from the muscular tissue in which they are embedded. Studies can be carried out on these vessels to determine whether the functional changes that often occur may have local or distal significance in cardiovascular disease, and for analyzing underlying mechanisms.
System Components – The two instruments explained in more detail below are the Extravascular Pressure Control, Model EV-, 1 and the Signal Generator, Model SG-1. Brief, , ly, the EV-1 produces selectable, sustained EvP when used alone, and acts as an intermediate link allowing the SG-1 to create sinusoidal and pulsatile extravascular pressure waveshapes.
          The sealed vessel chambers, Model CH/1/AU or its self-heated cousin Model CH/1/AU/SH are key components of this system. These chambers are described elsewhere on our website.
          A laboratory compressed gas tank and a regulating valve (user supplied) for reducing the pressure to 6 to 8 psi is the fundamental source of system pressure. It is then modified by signals received from the EV-1 via the Electronic Servo Valve to create the desired steady or non-steady extravascular chamber pressures. The servo valve is included as part of the EV-1.
  
EV – 1 Pressure Control Unit –
           The extravascular pressure (EvP) in the sealed chamber is sensed by a solid-state pressure transducer. The signal from this transducer is connected to the EV-1 Control Unit where it is compared with either the internal pressure signal set by the EV-1 pressure dial, or one of the external pressure signals fed into either the Function Generator or Signal Generator input jacks. Any difference between these two signals regulates the Electronic Servo Valve output pressure so that the two presures are the same.
Internal Pressure Signal Mode:  Here, the signal corresponding to the Pressure Dial setting calibrated in mmHg establishes the extravascular chamber pressure. This pressure is sustained until a new presure is selected. The panel meter reading also shows the chosen extravascular pressure in mmHg which can be accessed for data acquisition at the rear panel Pressure Signal jack.
External Pressure Signal Mode: When switched to this mode, various  extravascular pressure waveshapes can be created to match external input signals. Again, the actual extravascular pressure can be accessed for data acquisition at the rear panel Pressure Signal jack.
 Function Generator signals can be obtained from a computer program written by the user and a computer having a D/A computer board that supplies analog voltages of 10 mV/mmHg. In this way, various simple or complex, time-dependent pressures can be applied to the chamber.
Signal Generator – The Model SG-1 is used to establish sinusoidal and pulsatile extravascular waveshapes as described ahead.

EV-1 Specifications
Pressure Range:             0 – 250 mmHg
Pressure Output Signal: 10 mV/mmHg
External Input Signal:    10 mV/mmHg
Power:                            100-120 VAC/60 Hz or 200-240VAC/50Hz
Size/Weight:                  13 x 11 x 36 cm (H x W x L)/3.1 kg
         
 
 

 
SG-1 Signal Generator -
          This instrument provides extravascular Sinusoidal or Pulse pressure (EvP) waveshape signals as shown below to the sealed chamber via a cable connection to the EV-1 when used in external signal mode. User-friendly pushbuttons are used to program upper and lower limits of the pressures as well as pulses per minute and other parameters that may best suit the experimenter’s protocol. In both the Sine and Pulse Modes pulse rates can be selected as appropriate for humans or for small animals.
 
 

Quick Summary
Flow Rate Instruments
Measurement & Control
 FC

 Flow Control Peristaltic Pump

For establishing flow rates
 

 Microflowmeter

For measurement of flow rate

Flow Indicator

To monitor & record flow rate
of FC or PS/200
Miniature Oxygenators    
   
Models OX & OXR
 
 
For Perfused Preparations
        Blood Vessels
                Vascular Beds
                        Organ Chambers
                                Cell Cultures
 
 
 
   
   
¨     Allows gas exchange into perfusate
¨     Eliminates foaming when oxygenating protein-containing buffers
¨     For perfusion rates of µl/min to ml/min
¨     Small priming volume
¨     Replaceable membrane fiber cartridge (Model OXR)
¨     Large exchange surface area
¨     Minimal perfusate pressure loss
Superior performance to bubble & flat sheet membrane oxygenators
Polypropylene Hollow Micro Fiber Array
Hollow microporous fibers: 240 µm I.D., 28 µm wall thickness.

 
 
 
 
 
 
 
 
 
 
 
 

 
 

     
 
Model OX
Model OXR
Number of fibers
162
162
Exchange surface area
115 cm2
115 cm2
Active fiber length
7.5 cm
7.5cm
Casing material
Lucite or Polycarbonate
Polycarbonate
Casing O.D./length
2.5/
2.5/13.5 cm
Priming volume
<1 ml
<1 ml

 

 
Features
·        Oxygenators may be placed anywhere in flow path
·        Separate Luer fittings for perfusate and gas
·        Fibers cartridge can be chemically cleaned or replaced (Model OXR)

 

Video Dimension Analyzer

Automatically Measures Lumen Diameter & Wall Thickness

Model V94

Continuously measures the lumen diameter and wall thickness of isolated, cannulated vessels of 50 - 350 µm diameter that may be imaged through a television camera attached to a microscope. For larger vessels, or those with thick walls, only the outside diameter can be measured. These measurements are displayed on digital panel meters, and analog output signals acquired for recording. Changes in dimensions arising from vessel constriction or dilation are automatically followed with rapid (<20 ms) time resolution.

The principle of the instrument is based on sensing optical density changes of the vessel image at a chosen scan line seen on the TV monitor. Rotation of the camera allows the scan line to perpendicularly intersect the long axis of the vessel. Initially, the width of two windows in the scan line is set to bracket the vessel wall. Trigger controls are then adjusted to sense the wall that is more optically dense than the lumen and the image outside the vessel. A switch also allows triggering at the transition from a dark background to an optically bright one. This feature can be useful for fluorescent tissue images and certain other situations. Once these settings are made they do not require further adjustment during the course of the experiment.

APPLICATIONS

Record lumen diameter as a function of:

  • Drug Concentration
  • Pressure
  • Perfusate Flow
  • Membrane Potential
  • Fluorescent Dye Signals
  • Neurotransmitter Release

Follow

  • Vasomotion
  • Myogenic Responses
  • Cardiac Cell dimensions

Calculate

  • Wall Tension and Wall Stress

Observe

  • Influence of Endothelium

FEATURES

  • Continuous display of lumen diameter and wall thickness as vessel changes size
  • Eliminates subjectivity in measurement
  • Calibrated voltage outputs for data acquisition
  • Simplified operating controls
  • VCR recorded images may be analyzed for additional data

V94 Specifications

Outputs - Analog Signals
10 mV/µm
Digital Meter Reading
1 µm
Measurement Precision
1 - 2 µm
Analog Signals Time Resolution
< 20 ms
Power
100 - 120 V/60Hz
or 200 -240 V/50Hz
Size/Weight
13 x 21 x 36 cm/3.4 kg

 

SG-1 Specifications
    Sine Mode
        Extravascular Systolic & Diastolic Pressure Ranges: 0 – 250 mmHg
        Pulse Rate: 30 – 360 pulses/min
    Pulse Mode
        Extravascular Systolic & Diastolic Pressure Ranges: 0 – 250 mmHg
        Pressure Rate: 1 – 50 mmHg/s
        Extravascular Systolic and Diastolic Durations : 1 – 999 s (16.7 min), or greater    
 
 
    Power: 100-120 VAC/60 Hz or 200-240VAC/50Hz
    Size/Weight: 22.5 x 7.5 x 17.5 cm (L x H x W )/1.0 kg 

Peripheral System Components,
    Equi, , pment which may be needed to carry out cannulated vessel and other experiments are contingent upon the nature of the planned studies and protocols, budget constraints and apparatus that may be already available in the investigator's laboratory. Living Systems offers many of these components as a convenience to those first setting up a laboratory for vascular studies, as well as LSI instrument parts or supplies which may require replacement. Some of these are listed below.
Microscopes - For many years we have supplied the Nikon TS100-F inverted microscope. It has excellent optical clarity, a TV camera port, and is moderately priced. There is ample space on its mechanical stage with the 96-well carrier which fits all LSI's Single and Dual Vessel Chambers. We also offer the Nikon SMZ/645 or SMZ/660 dissection microscope that is useful for tissue dissection and the tying of vessels to the cannulas.
TV Camera and TV Monitor - We currently supply the CCD monochrome Sony XC-ST30 and XC-ST30CE for domestic and foreign use, respectively. These cameras have fine image resolution and can tolerate a wide range of image illumination. A DC power supply is supplied. Also available at a reasonable cost is a twelve-inch monochrome monitor for domestic or foreign use .
Cannulas - LSI makes borosilicate glass cannulas for all vessel chambers. They have a cleanly beveled tip, and are sold in packs of 12. Tip size may be specified to best match the vessel lumen size. Commonly supplied sizes in µm are: 40 - 60, 80 - 100, 100 - 120, 120 - 150, and 150 - 200. Other size ranges are available by request.
Flow-thru Pressure Transducers - These solid-state units have Luer fittings and readily connect to the perfusion line. The electrical signal 4-foot cable terminates in a telephone connector suitable for connection to the Pressure Servo Control unit (e.g., PS/200), the Perfusion Pressure Monitor (PM/4), or the microFlowmeter (FM-2).
Tube Sets - These are used to change the volume flow range of the peristaltic pumps in the Pressure Servo Control unit (PS/200) and the Flow Control pump (FC). Except for the largest tube set size they can be supplied as single or are dual tubes; the duals can be paralleled for greater flow, or used to supply different fluids in a Dual Vessel Chamber setup. The sets available and approximate maximum flow rates follow:
Tube Set Size
Maximum Flow Rate (µl/min)
015
100
020
230
031
330
062
1,150
093
2,280
 
Vessel Dissection Dishes are Petri dishes coated on the bottom with a layer of Sylgard so that the tissue can be pinned out for vessel dissection.
Glass Cannula Tubing is supplied for those wishing to draw and grind their own cannulas.
Pen Recorders are a useful adjunct to any experiment where hard copy on paper is desired. The Kipp & Zonen, BD 300 4-channel recorder has a sufficient number of channels to collect the key data; e.g. proximal and distal pressures, vessel diameter, and flow. We supply this state-of-the-art instrument with pen offset compensation, and with options for data logging to a built-in floppy disk, and a print head which imprints the variables' sensitivities and other chart recording parameters.
PC Data Acquisition Systems store all the data voltage signals and essentially transforms your computer into a recorder. We supply three models of the DATAQ system, which can accept as many as 32 signal variables. The instrument connects to the computer's parallel printer port. Included software provides a host of extremely useful calibration and analysis functions.
Flow Resistors are made using small bore Tygon tubing having luer fittings at each end.  These are supplied with a calibration of the flow resistance in the range of approximately 0.05-1.00 mmHg/µl/min (50-1000 Halps; 1 Halp = 10-3 mmHg/µl/min). For example, a flow resistor of 0.10 mmHg/µl/min (100 Halps) will cause a pressure difference across the resistor of 5 mmHg at a flow rate of 50 µl/min.
Pressure Calibrator - This desk model mercury manometer permits accurate calibration of the pressure transducers used in our Pressure Servo Control and Pressure Monitor instruments.  It is supplied complete with tubing and inflation bulb.
NEW     Flow-thru miniature         combination pH electrode
·        Continuous pH monitoring
·        Place in line with flow path. For example, perfusate or superfusate connections of cannulated vessel chambers
·        Luer-lok male fittings
·        Compatible with all pH meters
·        For solution temperature measurement use in series with LSI in-line “Tee-mounted” thermistor (Model THS/Tee)
Vermont quarter (23 mm dia.) shown for size

Model PH/Tee

          pH sensitivity: 0 – 14
          Response time: 5 – 15 s
          Solution & electrode; 3 mM KCl & Ag/AgCl
          Overall size: 40 x 60 mm (excluding 2 m cable)
          Includes: bottle of reference solution, syringe with filling tip and Alconox cleaning solution
          Standard BNC termination (specify other)
Other components that LSI offers include: pH instruments, temperature probes and meters, superfusion pumps, heat exchangers, stage micrometers, and micropipette pullers and grinders.
 
 
 
 

Questions and Answers About LSI Products
   
CONTENTS
 
Top

Choosing a chamber

How do I choose a chamber that is best suited to my applications since LSI offers many different models?
  1. Talk with us.
  2. Decide whether you may want to run experiments on one or two vessels. Dual vessel chambers enable one to:
    - Test a second, equilibrated vessel after the experiment on the first vessel has finished, or is equilibrating from exposure to an agent.
    - Connect the two vessels as in a bioassay.
    - Compare responses of two vessels that may be of different sizes, from different vascular beds, or superfused and/or perfused with different agents.
    For these features, choose one of the dual vessel chambers. Otherwise, consider choosing one of our single chambers, and see if its features are sufficient for your needs.
  3. Select a chamber which has the unique features in the table below required by your experiments.
Features Chamber
A small volume for using peptides or expensive agents. CH/2/SH, CH/1/AU/SH
Ability to work with fluorescent markers (calcium, pH, etc.) where objectives have a short working distance CH/1, CH/1/SH, CH/1/AU, CH/1/AU/SH
Enable a large diameter objective (e.g., confocal) to be placed very close to the vessel CH/1, CH/1/SH, CH/1/AU, CH/1/AU/SH
Has an aluminum base for heating the solution CH/1/SH, CH/2/SH, CH/1/AU/SH
Capability to quick freeze or rapidly fix vessels CH/1/QT
Release neurotransmitters from nerve varicosities using platinum stimulation electrodes. All except CH/2/SH
Ability to rotate or invert a cannulated vessel and make confocal observations CH/1/R
Be able to apply an extravascular pressure to a perfused, pressurized vessel, or perform long-term experiments in these sealed chambers CH/1/AU, CH/1/AU/SH
  Top
Non-superfused chambers
Do all chambers require superfusion of the vessel to maintain temperature and pH?
No, the CH/2/SH, CH/1/SH and CH/1/AU/SH have an aluminum base. Current to the base is supplied from an electronic unit to control the bath temperature so that buffers like HEPES or MOPS may be used.
  Top
Branched vessels
Can I make measurements on small vessels that have branches?
Some vascular beds from which small vessels are dissected have smaller side branches that lie between the cannulated vessel ties. These branches could cause leaks in a pressurized vessel. They must be located and carefully tied off while visualizing them under high power – perhaps requiring use of a compound microscope for higher magnification than a dissection microscope.
  Top
Cannulas
Can I draw my own cannulas, or is it necessary to buy them from LSI?

yes, we can supply borosilicate tubing for those having access to a micropipette puller and grinder.

What size cannulas are best to use?
The size is not important when blind-sac experiments are to be done. However, for perfused vessel experiments we recommend roughly matching the outside tip diameter to the lumen diameter of the vessel.
  Top
Coverslip Replacement
What cement is recommended for sealing a new 22 mm round coverslip in the chamber?
A flowable windshield sealer, Dow Corning # 734 is best. It can be obtained from an automobile supply store, or from VWR.
Top

Measurement of Large Diameter Vessels

 

Can I visualize the diameter of large vessels – greater than around 350 µm, or those having thick walls?
Yes. Generally, these measurements are limited to only the outside diameter since the light is dispersed passing through the vessel making the inside diameter difficult to detect. Our instruction book details how this is easily done. Adapters can be purchased from LSI that will change the camera magnification so that larger vessels can be measured using the Video Dimension Analyzer. Contact us for specific details.
  Top
Changing Optical Density Detection
What is the purpose of the internal switch in the LSI Video Dimension Analyzer, V94, which reverses the normal image detection circuitry of light to dark?
This allows measurements of diameter to be made on vessels imaged by incident light when using a dissection microscope, or a microscope having dark-field illumination.
Top

Flow Pulsations

Can the flow fluc, tuations from this peristalt, ic pump be minimized, and about how large are they?

When the pump has b, e, en calibrated and flow set either by the speed dials, or from an external voltage, the mean flow will be that desired. However, the pump will produce a pulsating flow. The amplitude and frequency of these pulsations depend on the pump speed, the tube set used in the pump, and possibly on the system perfused by the pump. For example, a 015 tube set delivering 100 µl/min may have flow fluctuations of about ± 3 µl/min, and half that at 50 µl/min.

A simple windkessel placed in the output line from the pump will reduce these fluctuations at the expense of slowing down the response to any flow changes that might be effected. The windkessel is a ‘tee’, connector with the branch at right angles to the flow path having a closed-off tube which traps some air. The larger the volume of the air trap, the more the pulsations are diminished.

  Top
Recording Flow
Can a signal voltage be obtained from the pump so that the actual flow can be recorded?
Yes. There is an output jack on the FC unit that provides a voltage proportional to the flow. A simple calibration procedure is used to establish this factor (in volts/µl/min). Our Flow Indicator, FI-1 can be used with the PS/200/Q to obtain a similar voltage output.
  Top
Flow Indicator
Is there a way to monitor the flow while running an experiment?
Yes, the Flow Indicator (Model FI-1) instrument has a digital meter that shows the flow directly in µl/min. It connects to the Model FC, or our PS/200/Q pump unit. An output jack for recording the flow is also provided. Also, the microFlowmeter, FM/2, enables direct reading of the flow rate.

Top

Pressure > 200 mmHg

Can pressures greater than 200 mmHg be measured and used for control?
Yes, the analog voltage signal from the Pressure Out connector is linear to about 300 mmHg. Use a digital voltmeter to read this voltage (10 mV/mmHg). However, the digital panel meter of the Pressure Servo Control will read ‘1’, an overload condition.
  Top
Computer Control
Can I use a computer to program pressure protocols?
Yes. Using a digital-to-analog (D/A) converter, program the amplitudes and time sequence of the voltages that will be outputted from the D/A into the External Input jack of the Pressure Servo Control unit.
  Top
Pressure Pulsations
How can the peristaltic pump pressure fluctuations be minimized?
These pulsations are due to tube expansion when one of the rollers moves off the tube. First of all, use as large a tube set (e.g., the 093 tube set) in the pump as possible when the pump is providing a controlled pressure at the distal end of the cannulated vessel system. A simple windkessel may also be placed in series between the system’s distal end and the pump. The windkessel is a ‘tee’ connector with the branch at right angles to the flow path having a closed-off tube which traps some air. The larger the air trap volume, the more the pulsations are diminished, but at the expense of slowing the response time from 1 – 3 seconds to 15 seconds. It is possible in this way to reduce pulsations to as much as ± 1 mmHg. Alternatively, the pulsations may sometimes be minimized by raising or lowering the pump height to closely match the inlet and outlet pressures of the pump.
  Top
Perfusion Pressure Control
Can I use the Pressure Servo to control the vessel pressure (PAV), or maintain the difference in pressure (dP) between two locations in an isolated vessel or vascular bed?
Yes, in conjunction with the Perfusion Pressure Monitor, use either the dP or PAV output and connect it to the PAV jack on the rear of the PS/200/Q (see instruction manuals).
  Top
Necessity for Recalibration
How often do the ZERO and SCALE calibrations have to be made?
Normally, the drift of the ZERO calibration is less than 1.5 mmHg in 24 hours when the ambient temperature changes in the room are not significant. The SCALE calibration does not have to be readjusted from day to day.

Top

Use of upright microscope

Is it OK to use a non-inverted microscope to visualize the vessel in the chamber?
Yes, but there are a few disadvantages. Fluid surface movements caused by superfusion can cause some jumpiness in the image. Although, the Video Dimension Analyzer will follow these movements and measure correctly, it is a little disturbing to view on the TV monitor. Also, any pH or temperature probe located in the chamber will move when changes in focus are made if their associated holder does not move with the stage. Another problem is that moisture may accumulate on the objective to cloud the image. In sum, an inverted microscope is preferable.

 

Top
Large Coverslips useful for Confocal Microscopes
Is there a chamber where the 22 mm diameter coverslip is not recessed from the base so that large diameter objectives such as found in confocal microscopes can be brought extremely close to the vessel?
Yes. The CH/1/SH has a non-recessed coverslip that is made for this purpose.
  Top
Sources for Tools & Supplies
Where can dissection tools, stopcocks, tubing, valves, etc. be obtained?
Sources for dissecting instruments such as Dumont # 5 or # 55 forceps and micro Vannas scissors are Fine Science Tools and Roboz. For other components see the Cole-Parmer or VWR catalogs; they contain a wide variety of components to choose from.
  Top
Representation
Do you have sales representatives in various countries?
No, except for Japan.
Our trained representative in Japan is:
     Physio-Tech, Co. Ltd.
     1-6-3 Iwamoto-cho Chiyoda-ku
     Tokyo 101-0032, Japan
     Fax: 81-3-3864-2787          e-mail: sales@physio-tech.co.jp
 

Elsewhere, we sell direct in order to keep our prices low and provide customers with our application expertise and other services.

Top
 
What new products are you developing?
A pressure control instrument similar to our Pressure Servo Control PS/200 that will maintain pressure in a perfused vessel or tissue at flow rates from a few microliters/minute to as high as 30 ml/min.

A pulse pressure generator that superimposes a pulse pressure on the vessel while maintaining the mean transmural pressure. Physiological pulse pressures for arteries will be obtainable from 0 to ±40 mmHg over a frequency range up to 6 Hz, or more.

An essentially pulseless flow pump adjustable for flow rates from 10 µl/min to 30 ml/min.

Please let us know of your interest in these, or other new instruments.

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