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Biomedical subjects

A B Carter

Publications and source records attributed to A B Carter.

At least 19 recordsLinked to original sources

Reticulocyte counting using flow cytometry.

A flow cytometric method for the quantitation of reticulocytes was refined for routine laboratory use. Blood (2 microliters) is added to 2 ml of 0.4 microM thiazole orange in phosphate buffered saline, incubated at room temperature for 90 minutes, and analysed on a Coulter EPICS Profile flow cytometer, with gating for red cells on the basis of forward and right angled light scatter. Blood (2 microliters) is also incubated with phosphate buffered saline alone as an unstained control. The adult reference range (mean +/- 2 SD), established from 30 laboratory personnel, is 19.4-59.2 x 10(9)/l (0.2-1.6%). Comparison of this technique was made on 39 selected patient samples with visual counting of cells stained with brilliant cresyl blue. The correlation between the two methods was 0.99 with slope 0.96 and intercept 0.02. The precision of the automated technique in three subjects with reticulocyte counts of 0.12%, 1.84%, and 14.3% was 33.3%, 7.3%, and 1.4%, respectively (coefficient of variations). In three patients studied serially after intensive chemotherapy, in whom the reticulocyte count quantitated by routine visual methods approached zero (0-0.1%) for eight to 18 days, the automated counts varied between 0 and 0.5%. Flow cytometric reticulocyte counting is thus a simple and highly reliable methodology for the quantitation of normal and raised reticulocyte counts but cannot be reliably used to quantitate a subnormal level.

Benzothiazoles

An evaluation of the Coulter VCS differential counter.

An evaluation of the Coulter VCS (volume, conductivity, light scatter) automated differential counter demonstrated satisfactory correlations with manual 800-cell differential counts for neutrophils, lymphocytes, monocytes and eosinophils. For the detection of abnormal cells, 12.2% of samples gave false-negative results on the VCS, and 13.4% gave false-positive results. However, only 0.8% of the false-negatives would be expected to be picked up by a standard 100-cell manual differential count. Carry-over accorded to manufacturer's specifications and throughput was 60 samples/h. Reference normal ranges have been established and the instrument's precision and performance with leucopenic and neonatal blood samples assessed.

Adult

Detection of important abnormalities of the differential count using the Coulter STKR blood counter.

An assessment of the three part differential provided by the Coulter STKR blood counter showed good correlation when compared with an 800 cell manual differential. Satisfactory flagging of eosinophilia, basophilia, and the presence of immature cells was found. The use of variables derived from the STKR in conjunction with interpretive reporting and user-defined flagging enabled this department to reduce considerably the numbers of films requiring manual differential counts.

Blood Cell Count

The use of the H*1 in predicting marrow recovery following ablative chemotherapy in leukaemia and lymphoma.

Twenty-three cytopenic episodes in 18 patients undergoing ablative chemotherapy for the treatment of leukaemia or lymphoma were monitored from commencement of treatment until recovery, by automated differential counts using the Technicon H*1 Autoanalyser, with particular reference to abnormal white cell flags and large unstained cell (LUC) percentage. The blast flag was indicated in this recovery phase in 100% of patients and in 85% this preceded bone marrow recovery (defined as neutrophil count greater than 0.5 X 10(9)/l) by a mean of 10 days. On average the blast flag was indicated for 8 days in total. Bone marrow function continued to improve in all patients with no evidence of relapse. An increase in the LUC percentage on the differential count reached a maximum at 18 days, 6 days prior to marrow recovery. The ability to detect impending marrow recovery by means of the positive blast flag, may be of great value when patients have been cytopenic for many days.

Autoanalysis

Comparison of mechanical techniques of cardiopulmonary resuscitation: survival and neurologic outcome in dogs.

Three currently available mechanical devices for cardiopulmonary resuscitation (CPR) were compared using a canine cardiac arrest model. Twenty-four-hour survival without neurologic deficit was the goal. A group of 30 large mongrel dogs was divided equally among Thumper CPR, simultaneous compression and ventilation (SCV) CPR, and vest CPR. Ventricular fibrillation was induced electrically, and after 3 minutes of no intervention, one of the three types of mechanical CPR was performed for 17 minutes. SCV CPR and vest CPR produced significantly greater aortic and right atrial systolic pressures than Thumper CPR (P less than .03). The SCV CPR technique also produced significantly higher aortic diastolic pressure and right atrial diastolic pressure than either of the other methods (P less than .03). However, coronary perfusion pressure was not different among the three mechanical methods. No differences in immediate resuscitation, 24-hour survival, or neurologic deficit scores at 24 hours were found. Neither SCV nor the vest techniques of CPR appear better for survival or neurologic outcome than standard cardiopulmonary resuscitation performed with the Thumper.

Animals

Long-term survival with open-chest cardiac massage after ineffective closed-chest compression in a canine preparation.

The ultimate goal of cardiopulmonary resuscitation (CPR) is long-term, neurologically intact survival. This study examined whether open-chest cardiac massage could improve 7 day survival and neurologic function when instituted after the failure of standard closed-chest compression CPR. Twenty-nine mongrel dogs were anesthetized and then instrumented with catheters to monitor right atrial and ascending aortic pressures. Ventricular fibrillation was induced and after 3 min standard CPR was begun. Standard CPR was performed with a Thumper programmed for 2 inch chest compressions at 60/min with a 50% duty cycle. External defibrillation was attempted twice after 15 min of ventricular fibrillation. Unsuccessfully defibrillated animals were randomly assigned to either an additional 2 min of continued closed-chest compressions, or 2 min of open-chest cardiac massage. All animals underwent a period of advanced cardiac life support and were followed until they were resuscitated or died. Follow-up care, including scoring of neurologic deficit, was performed for 7 days. In dogs receiving open-chest cardiac massage there was significantly more immediate resuscitation success (14/14 vs 5/14; p less than .005), 24 hr survival (12/14 vs 4/14; p less than .005), and 7 day survival (11/14 vs 4/14; p less than .02) than in those receiving continued closed-chest compression. Open-chest cardiac massage significantly improved long-term outcome when instituted after 15 min of ineffective closed-chest compression.

Animals

CPR-induced trauma: comparison of three manual methods in an experimental model.

Cardiopulmonary resuscitation (CPR) often results in traumatic injury to the patient. Differences in CPR-induced trauma among various forms of manual, external CPR, however, are unknown. We compared CPR-induced trauma among manual standard (STD) CPR at 60 compressions per minute; high-impulse compression (HIC) CPR at 120 compressions per minute; and interposed abdominal compression (IAC) CPR at 60 compressions per minute. A large (24 +/- 3 kg) mongrel canine model was used. Ten animals were assigned to each type of CPR. Each received 17 minutes of CPR, applied to produce the best possible coronary perfusion pressure without obviously damaging the dog. Defibrillation was attempted at 20 minutes. Necropsy was performed at the time of death or after sacrifice at 24 hours. Careful postmortem examination of the thorax, lungs, heart, abdomen, and great vessels was performed. A semiquantitative trauma score of 0 to 5 was assigned to each area with a possible maximal score of 25. There was no difference in trauma scores among STD (6.4 +/- 1.5), HIC (9.4 +/- 1.4), and IAC (8.1 +/- 1.3) methods. No significant correlation was found between the method of CPR and the different types of trauma. Specifically, IAC did not produce an increase in liver lacerations nor did HIC produce a significant increase in thoracic or pulmonary injuries. Six of 20 initially resuscitated animals expired during the 24-hour follow-up period due to CPR-induced injuries. Four of these six had extensive pulmonary trauma, including pulmonary hemorrhage or edema. Liver lacerations were the second most lethal injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance

Twenty-four hour survival in a canine model of cardiac arrest comparing three methods of manual cardiopulmonary resuscitation.

Two new modifications of manual cardiopulmonary resuscitation, high impulse compression at a rate of 120/min and interposed abdominal compression at a rate of 60/min, have been reported to produce better hemodynamic responses than standard cardiopulmonary resuscitation at 60/min. However, the effect of these two new methods on initial resuscitation success and 24 hour survival is unknown. In this study, 30 mongrel dogs were divided into three equal groups, each treated with one of three types of manual cardiopulmonary resuscitation. Ventricular fibrillation was induced electrically in morphinized, endotracheally intubated dogs emerging from halothane anesthesia. After 3 minutes of circulatory arrest without intervention, one of the three techniques of manual cardiopulmonary resuscitation was begun, and continued for 17 minutes. Defibrillation was performed at 20 minutes. Successful resuscitation was defined as a mean arterial blood pressure of at least 60 mm Hg, without chest compressions, 10 minutes after the initial defibrillation attempt. Intensive care was provided for 2 hours, including hemodynamic and respiratory monitoring, and drug intervention when required. Twenty-four hour survival and neurologic deficit were used as critical measures of outcome. Ten of 30 animals survived 24 hours with a mean neurologic deficit score of 5% (normal = 0, brain dead = 100). There was no difference in initial resuscitation success, 24 hour survival or neurologic deficit of the survivors among the three manual cardiopulmonary resuscitation methods. Aortic diastolic and calculated coronary perfusion pressures were similar for all three methods. Well performed standard manual cardiopulmonary resuscitation is as effective as these modified versions (high impulse compression and interposed abdominal compression) when compared in the same animal model.

Animals

Manual versus mechanical cardiopulmonary resuscitation in an experimental canine model.

Manual and mechanical chest compressions during CPR were compared in the canine model. Endpoints were hemodynamics produced during CPR, resuscitation success at 30 min, 24-h survival, neurologic function of survivors, and CPR-produced trauma. Ten animals in each group underwent 20 min of ventricular fibrillation, during which CPR was performed for 17 min. Hemodynamics produced with manual and mechanical chest compressions were similar. Seven of ten animals in each group were resuscitated. Five animals from the manual group and four animals from the mechanical group survived for 24 h. Neurologic function of survivors was excellent and similar in each group. There was no significant difference in trauma between the two types of chest compression. The similar results for manual and mechanical chest compression in this canine model suggest that different experimental CPR studies can be compared regardless or whether manual or mechanical chest compressions were performed.

Animals

Indirect auscultatory systolic and diastolic pressures in the anesthetized dog.

The auscultatory method was used to obtain indirect systolic and diastolic pressures in 13 dogs anesthetized with either halothane or sodium pentobarbital (30 mg/kg of body weight). Korotkoff sounds were obtained, using a 1-cm (diameter) piezoelectric element cemented to the inner surface of a pediatric cuff (width 5.5 cm) which was placed on a shaved thoracic limb (membrum thoracicum). The signal from the piezoelement was amplified by a differential amplifier (30 to 200 Hz) and a commercially available audio amplifier. Indirect pressure (I) was compared with direct pressure (D) in the brachial, femoral, or carotid artery. The linear regression lines and correlation coefficients (r) for the data were as follows: systolic, I = 0.94 (D) + 1.1, r = 0.98; diastolic, I = 0.99 (D) + 3.2, r = 0.99. The quality of the Korotkoff sounds and the accuracy of the determinations were best in the halothane-anesthetized dogs. These results indicate that indirect auscultatory systolic and diastolic pressures are in excellent agreement with the directly measured pressures.

Anesthesia

The effect of cryopreservation of lymphocytes on E rosetting ability: a study in lung cancer patients and controls.

Two methods of measuring total T cell percentages have been used to assess the effect of freezing and storage on the ability of lymphocytes to form rosettes in blood transfusion donors, laboratory staff, patients awaiting surgery for non-malignant conditions and 48 preoperative lung cancer patients. A significant reduction in rosetting ability after freezing was found for the surgical patients group but not for the other groups. With frozen lymphocytes we have found the same significant decrease in the percentage of T cells seen with fresh lymphocytes when lung cancer patients are compared with the blood donor group. A significant difference in the percentage of T cells detected by the two assays with frozen lymphocytes was found in the control groups.

Blood Preservation

Bell's palsy.

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Facial Paralysis