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Biomedical subjects

J Umlas

Publications and source records attributed to J Umlas.

At least 37 records · Page 2Linked to original sources
PubMed1988

Warfarin-induced alopecia.

Earlier reports of the association between oral anticoagulation and alopecia describe a high incidence of this complication (42 to 78 percent). However, judged by its extreme rarity in a survey of eight experienced, busy academic dermatologists in Boston, this association is not common, nor is the assumption that the alopecia tends to occur soon after the administration of warfarin necessarily true. Nevertheless, alopecia persists in the face of continued warfarin administration; the time required for hair to regrow after discontinuation of the drug may be too long to be practical if continued anticoagulation is necessary; the effect of oral substitutes for warfarin is unknown; and alopecia may recur if the patient is rechallenged with warfarin.

Alopecia Areata↗
PubMed1984

Heparin monitoring and neutralization during cardiopulmonary bypass using a rapid plasma separator and a fluorometric assay.

Avoidance of over- or underheparinization during cardiopulmonary bypass (CPB) is crucial in preventing bleeding or clotting. Currently no completely satisfactory method is available for measuring heparin levels--a method that would be rapid, inexpensive, specific, and reproducible. We combined the use of two devices, a rapid plasma separator and a fluorometric heparin assay system, in an attempt to satisfy these requirements in 15 patients having CPB during cardiac surgical procedures. The first instrument separates plasma from whole blood using a pneumatic filtration principle, while the heparin assay system measures the effect of heparin on thrombin conversion of a synthetic fluorogenic substrate. Accurate plasma heparin levels can be generated in less than five minutes, and the assays are inexpensive and easy to perform. Performing heparin assays at critical intervals during CPB allowed desired heparin levels to be maintained and the protamine dose for heparin neutralization to be reduced to a minimum. In addition, studies for heparin rebound revealed negligible rebound up to six hours postoperatively despite the reduced doses of protamine. There were no hemorrhagic or clotting complications in the series.

Cardiopulmonary Bypass↗
PubMed1983

Transfusion of patients undergoing cardiopulmonary bypass.

Although certain hematologic changes that occur as a consequence of cardiopulmonary bypass are unique, their influence on the transfusion requirements of open-heart surgical patients is not different from that on other bleeding patients. While knowledge of the peculiarities of open-heart surgery is important for the blood bank medical director, this clinical situation can be managed using the basic principles of component therapy as they apply to other clinical situations.

Blood Transfusion↗
PubMed1983

A device for rapid plasma separation.

The STATSEP Plasma Separator (Instrumentation Laboratory, Inc, Lexington, MA), a device for rapidly separating plasma from whole blood, generates plasma at the rate of 0.5 ml/min by filtration rather than centrifugation. When plasma was separated by conventional centrifugation or by the plasma separator, there were no clinically significant differences in concentrations of a variety of important analytes in duplicate specimens. In addition, there were no clinically significant differences in measurements of prothrombin times (PT) and partial thromboplastin times (PTT) on plasmas generated by the 2 techniques. This device, therefore, reduces the analytic time of these frequent coagulation tests by 9 min. The above tests were performed on patients with leukemia and with benign and neoplastic elevations of platelet counts, with no differences seen between plasma specimens separated by either technique. Elevated hematocrits, however, require as much as 2 min to produce 0.5 ml of plasma. Both the machine and disposables are inexpensive and easy to operate.

Blood Chemical Analysis↗
PubMed1983

Anticoagulant monitoring and neutralization during open heart surgery--a rapid method for measuring heparin and calculating safe reduced protamine doses.

Confident monitoring of heparin during cardiopulmonary bypass and subsequent neutralization by protamine has been hampered by the absence of an accurate, reproducible, rapid, simple, and specific assay for heparin. By using two new instruments in tandem, one of which produced 0.5 ml of plasma in 1 min and one which specifically measures heparin in 3-4 min, heparin levels are available in approximately 5 min. By performing heparin assays at a variety of intervals, it was demonstrated that 76% of patients receiving common doses of heparin during cardiopulmonary bypass may have plasma levels that are potentially too low. Minimum neutralizing doses of protamine may be calculated using the formula: (estimated blood volume + pump prime volume) X (plasma heparin level/100) X 1.1 + 50. These doses were nearly two-thirds of previous doses and were unassociated with increased bleeding, clotting, or clinically significant heparin rebound.

Biological Assay↗
PubMed1982

Comparison of filtration leukapheresis and centrifugation leukapheresis in treatment of lymphosarcoma cell leukemia.

A patient with lymphosarcoma cell leukemia resistant to chemotherapy was treated with filtration leukapheresis and centrifugation leukapheresis. Filtration leukapheresis removed only 10(11) leukemia cells per 8.5 liters of blood processed, while centrifugation leukapheresis removed approximately six times as many leukemia cells from the same amount of blood. Lymph nodes and spleen diminished in size and the WBC count decreased after nine treatments. However, the patient remained markedly thrombocytopenic, and his bone marrow remained infiltrated with lymphosarcoma cells on repeat biopsy. This study shows that centrifugation leukapheresis is superior to filtration leukapheresis in removing significant numbers of circulating lymphosarcoma cells, though the clinical benefit of leukapheresis in this situation remains to be determined.

Blood↗
PubMed1978

Rapid reduction of platelet count in essential hemorrhagic thrombocythemia by discontinuous flow plateletpheresis.

Dramatic reduction of the platelet count by discontinuous flow plateletpheresis was achieved safely and swiftly in a patient with essential hemorrhagic thrombocythemia. The patient had a history of thrombo-occlusive arterial disease and on admission had gastrointestinal bleeding. This technic is recommended as an effective means of rapidly controlling marked increase in the platelet count and its consequences in the interval before chemotherapy becomes effective.

Aged↗
PubMed1977

Polybrene neutralization as a means of monitoring heparin therapy for extracoporeal cirulation.

Dose-response effects of heparin and protamine in 34 adult patients undergoing cardiac operations were monitored by an in vitro analysis utilizing hexadimetharine bromide (Polybrene) neutralization. Heparin administered prior to cannulation for cardiopulmonary bypass in a dose of 3.0 mg (300 units) per kilogram of body weight, and 1.5 mg (150 units) per kilogram for each subsequent hour of bypass, routinely produced circulating heparin concentrations greater than 1.0 units per milliliter of plasma. A protamine dose equal to 80% of the total number of milligrams of heparin given resulted in no detectable plasma heparin in 23 of the 34 patients one-half hour after administration. No patient required protamine in an amount greater than the total number of milligrams in the heparin dose to achieve heparin neutralization. Modest postoperative chest tube drainage (mean, 784 ml in 48 hours) in these patients provides clinical support for low-dose protamine administration for heparin neutralization at the conclusion of cardiopulmonary bypass.

Adult↗
PubMed1976

The pathology of esophageal intramural pseudodiverticulosis.

The gross and microscopic findings of an atuopsied case of esophageal intramural pseudodiverticulosis are presented. The source of the pseudodiverticula is shown to be pathologically dilated pre-existing excretory ducts of the submucosal glands, with which the pseudodiverticula often remained in continuity. Unlike what has been previously reported but poorly documented, the submucosal glands themselves did not contribute to the structure of the pseudodiverticula, the number of duct-gland units was not increased, and the thickening of the wall of the esophagus was the result of submucosal fibrosis, not hypertrophy of the muscularis propria. The etiology of this entity remains unidentified.

Autopsy↗
PubMed1975

The effect on blood coagulation of the exclusive use of transfusions of frozen red cells during and after cardiopulmonary bypass.

The essentially indefinite storage life of previously frozen erythrocytes (PFE), combined with the virtual freedom from hepatitis, high 2,3-diphosphoglycerate (2,3-DPG) content, and low level of HL-A antigens, should make its use in open-heart surgery attractive. However, since the suspension medium for PFE is usually saline, the potential exists for creating a hemorrhagic diathesis by accentuating the dilution of plasma procoagulants by the pump prime. To test this possibility, we used PFE exclusively in transfusing a group of 13 open-heart surgery patients; they were given no plasma or platelets. A control group of 12 open-heart surgery patients were transfused with only shelf blood. Determination of prothrombin times (PT), partial thromboplastin times (PTT), platelets, and fibrinogen were done at various intervals. No clinically significant differences between the two groups were seen in any of these parameters at any interval, and there was no significant difference between the groups in amount of chest tube drainage or transfusions in the first 24 hours. It is concluded that most open-heart surgery can be safely performed exclusively with frozen blood.

Blood Cell Count↗
PubMedDate not supplied

Washed hyperpacked frozen and shelf red blood cells.

In order to determine the maximum degree to which blood units could be packed and still be effective, shelf stored blood and previously frozen red blood cells were washed and hyperpacked to hematocrits of 90 to 98 per cent. These products had average volumes of 180 and 162 ml, respectively. When transfused into a group of patients with stable nonhemolytic anemias or with slow or intermittent blood loss, the hyperpacked shelf stored blood resulted in average hematocrit increments of 4.4 per cent; the hyperpacked frozen red blood cells resulted in average hematocrit increments of 3.4 per cent. Conventionally packed unwashed red blood cells had approximately 10 per cent more hemoglobin and volumes of 270 to 330 ml, but resulted in average hematocrit elevations of only 2.8 per cent. Unwashed blood hyperpacked to hematocrits of 90 per cent with removal of the visible buffy coat took much longer to administer. Thus, by washing and hyperpacking shelf stored blood or previously forzen red blood cells, transfusions with the minimal amount of extraneous material can be given.

Blood Preservation↗