Chrono-log Corporation, USA

OPTICAL AGGREGOMETER 490-4+

490 4+ Four channel platelet aggregometers all based on classic Born’s optical method of platelet aggregation measurement. 490 4+ is upgradable to an eight channel version.

490 4+ Four channel platelet aggregometers all based on classic Born’s optical method of platelet aggregation measurement. 490 4+ is upgradable to an eight channel version.

MEASURING PRINCIPLE

Optical method:

The Born-type aggregometer or optical aggregometer is a fixed wavelength spectrophotometer with a sample chamber (or chambers) heated to 37C. Provision is made for stirring of the sample because platelet to platelet contact is necessary to the determination of in vitro platelet aggregation. A beam of infra red light shines through two cuvettes, one containing PRP (the sample) and one containing PPP (the reference). The difference in light transmission outputs from the photodiodes is transferred to recording devices. The optical aggregation output is proportional to the continuously measured difference in light transmission between the test and reference samples. When a stimulus is added to the cuvette containing PRP and the platelets
respond, changes in light transmission occur and are recorded over time.

PRP, which is a turbid, is stirred in a test cuvette maintained at 37C. The light transmittance through this turbid sample is measured relative to the PPP blank. When the agonist is added, the platelets will form increasingly larger aggregates and the PRP will begin to clear, allowing more light to pass through. This increase in light transmittance is directly proportional to the amount of aggregation and is amplified and recorded as a signal on chart paper or digitized into a computer using software.

MAJOR MERITS

1.The system is FDA cleared and suitable for platelet aggregation studies in PRP, gel-filtered or washed platelets with over-range detection to prevent operation, if a base line is not settable.

2. The system module is supplied complete with AGGRO/LINK 8 interface software package for AGGRO/LINK Opti 4 for aggregation and vW cofactor Opti 4 for Ristocetin CoFactor testing as a complete system.

3. Allows tests to be performed with sample volume 500 µl standard or down to 250 µl with spacers reducing the blood draw volume, rendering it suitable for paediatric and geriatric samples equally well.

4. Very economical with cost per test reduced by almost 50%., while using the high quality, optimised and concentrated Chrono-Par range of reagents and kit for Ristocetin CoFactor assay.

5. Improved reliability with enhanced performance with the self calibration of optical circuit offering a greater level of user convenience.

6. Incorporates two-line LCD display for easy operator guidance with display for temperature, stirrer speed, PRP/reference selection, calibration mode and warning messages for error-free operation.

7. The heater block is under electronic control and selectable between 35°C and 39°C in steps of 0.1°C for excellent temperature control and does not allow operation if exceeding ± 0.2°C from the set temperature.

8. The stirrer speed is adjustable between 400 and 1200 RPM in steps of 100 RPM and an accuracy of 0.01 %, with a stirrer, stopped position for easy adaptation to specific protocols and does not permit operation if the deviation is more than ± 10 RPM from selected speed.

9. Provides for planned expansion with a growing need while protecting investment, with the capability to expand the two channel system into a complete four-channel aggregometer infield, with simple interconnecting cable.

10. The system is well suited for clinical applications including diagnostic studies, detection of von Willebrand disease, monitor the effect of antiplatelet therapy, detect heparin-induced thrombocytopenia and ideal for platelet research, pharmaceutical research and leukocyte aggregation studies.

TECHNICAL DATA

Test Channels : 4 Channels (One Module) or 8 Channels (Two, 4-Channel Modules) with: Optical Aggregation test PRP, gel-filtered or washed platelets with over-range detection to prevent operation if baseline does not set.

Front Panel display and controls:

LCD Display – 24 characters x 2-line Liquid Crystal Display, one per channel displays: Displays temperature in degrees celsius, stirring in RPM’s, PPP/reference select, calibration mode and warning messages.

Power ON/OFF switch.

Set Baseline pushbutton – Sets aggregation baseline to 0%.

Select pushbuttons – Selects temperature, stirring speed and PPP/ Reference [one pushbutton selects for (2) channels].

Set pushbuttons – To adjust temperature, stirring speed and PPP/Reference [one pushbutton sets (2) channels].

Calibration switch – Key-activated calibration of optical circuits.

Heater block – Electronic control can be set between 35.0°C and 39.0°C in 0.1°C steps.

Stirrer – 400 to 1200 RPM in 100-RPM steps with “stirrer stopped” position.

Test sample:

Volumes : 250 µL or 500 µL samples [spacer not required for micro-volume testing]

Cuvettes : P/N 312

Stir Bars : Reusable teflon coated P/N 313, Disposable P/N 311

General specifications (each module):

Power requirements – switch selectable 115 or 230 VAC; 50/60 Hz, 150 watts max.

Dimensions – 14” (35.5cm) wide, 8.5” (21.6 cm) high, 15”(38cm) deep

Weight – 19.3 lbs (8.75 kg)

Incubation wells – Two (2) wells per channel @ 36.5°C ± 1.0°C when temperature set at 37°C.

Output:

Serial : Internal AGGRO/LINK® interface for use with a computer and AGGRO/LINK® and vW CoFactor Opti8 TM software.

APPLICATIONS

Provides low cost aggregation systems for testing platelet function in platelet-rich-plasma (PRP) for clinical screening, diagnostic studies, pharmaceutical research ad platelet research studies.

Other clinical applications:* Detect Heparin-Induced Thrombocytopenia * Screen for Aspirin Like Defect * Differentiate between hereditary and acquired platelet disorders using combinations of different Chrono-PAR reagents * Monitor therapeutic dosage and patient compliance to inhibitory therapy.

Research Applications:* Study the effects of drugs on platelet aggregation * Study the effects of food substances on platelet function * Study platelet-to-membrane receptor site defects.

Aggregometer specifications

Automatic optical aggregation system, with internal software, for aggregation tests in PRP or gel filtered or washed platelets with the following attributes:

(I) Features:

(i) Four channel system with optical/turbidometric principle based aggregation, FDA cleared and CE marked.

(ii) Shall have an infra-red based optical system providing high sensitivity preferably with dual-beam detection system calling for platelet count difference of only 75×10 9 /L between test and reference sample for testing.

(iii) Shall have LCD or touch screen display for operator guidance with facility for continuous display of set and the actual temperature of heater block, stirrer speed, selection of PRP/reference, calibration mode with appropriate warning messages and operator alert.

(iv) It should be possible to field upgrade the basic four channel version into an eight channel optical aggregation.

(II) Technical specifications:

Test channel : Four, expandable to eight in field

Lamp source : Infra-red LED

Optics type : Twin well dual infra-red beam

Display : LCD, two or three line, for temperature, stirring, PRP/reference selection, calibration and warning messages

Warning and operator alert for : Automatic baseline setting with over the range detection, prevent operation if stir speed is not within ± 10 RPM, operation stopped if temperature not within ± 0.2°C at the set
temperature

Calibration : Key operated, for optical circuits

Heater block : Temperature electronically controlled 35 to 39°C
selectable within 0.01% accuracy

Incubation wells : Two per channel

Stirrer : 400 to 1200 RPM selectable in steps of 100 RPM and controlled within .01 %

Sample volume : 500 or 250 µl (without spacer)

Software packages : For (i) aggregation testing, (ii) Ristocetin Co-
Factor testing

(III) Software:

Window based data management system to run on a windows based compatible system with featuring:

(a) Should guide the operator with on screen instructions for standard dilutions and running tests.

(b) Calculation of best curve fit for two to six standard dilutions should be available with the copy.

(c) Should allow duplication runs for each standard dilution or test with facility to monitor coefficient of variation between replicates for standards or samples.

(d) It should be possible to rerun or delete a standard dilution, and facility should exist for storage of standard curves for future use.

(e) System software should provide for automatic adjustments of dilution factor with calculation of results in percent activity.

Test:

(a) “Windows XP” or updated version software for ease of operation, and convenient data reduction for aggregation and Ristocetin co-factor assay as standard.

(b) System should be able to display real time graph including amplitude and slope data with possibilities to store and recall the test curves and the associated data.

(c) The facility for computation of slope, amplitude, co-factor activity, coefficient of determination (r 2 ) log time, and area under the curve should all be available.

(e) Reports should be available in standard A4 format with possibility to export data files to spread sheet and or desktop publishing software.

Power: 230V / 50Hz operation

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