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Biomedical subjects

G Ramsey

Publications and source records attributed to G Ramsey.

54 records · Page 3Linked to original sources
PubMed1987

The definition of ABO factors in transplantation: relation to other humoral antibody states.

The first examples of hyperacute rejection of renal hemografts were seen almost 25 years ago when kidneys were transplanted to ABO incompatible recipients whose plasma contained antigraft isoagglutinins. Hyperacute rejection caused in sensitized recipients by lymphocytotoxic antibodies is similar in that the immune reaction triggers an acute inflammatory reaction that leads to widespread thrombotic occlusion and devascularization of the graft. The events after xenotransplantation between certain species are essentially the same. Potential strategies to avoid the precipitating antigen antibody reaction or to mitigate the resulting effector cascade are described.

ABO Blood-Group System↗
PubMed1986

Anti-Rho(D) in two Rh-positive patients receiving kidney grafts from an Rh-immunized donor.

Kidneys from an Rh-negative cadaver donor were transplanted to two Rh-positive patients. The donor's serum contained anti-Rho (D). In both patients, anti-Rho (D) was detected in their serum and on their red cells 3.5 weeks after transplantation. One patient had hemolysis. The antibodies persisted for nearly six months, despite graft rejection and nephrectomy in one case. These antibodies presumably arose from passenger B lymphocytes in the grafts from the Rh-immunized donor.

Anemia, Hemolytic↗
PubMed1984

The effect of intra-amniotic injection of triiodothyronine on pulmonary maturity in lambs at 130 days gestation.

Saline or triiodothyronine (T3) (50-1000 micrograms) was injected into the amniotic sac of 17 pregnant ewes under general anesthesia at 130 days gestation. Forty-eight h later, the lambs were delivered by hysterotomy. Cord plasma T3 and cortisol and amniotic fluid T3 were assayed, and the maturity of the fetal lung was assessed in terms of its pressure-volume response and its surfactant (lamellar body phospholipid) content. With the highest dose of T3, cord plasma T3 and cortisol were raised, and lung maturity was enhanced compared with saline-treated controls; the pressure-volume curve showed increased hysteresis on inflation and deflation, and the lung retained air on return to zero pressure. There was also an apparent, but not statistically significant, increase in the lamellar body phospholipid content of the lung. Irrespective of treatment, lungs which were more mature, in terms of their pressure-volume characteristics, tended to contain a higher proportion of lamellar body phospholipid relative to total phospholipid.

Amnion↗
PubMed1984

The pathology of superficially invasive, thin vulvar squamous cell carcinoma.

Thirty-six cases of vulvar squamous cell carcinoma 5 mm or less in thickness were studied, and potential predictors of lymph node metastases were evaluated. Tumor thickness and depth of stromal invasion were measured. Inguinal lymph node metastases were present in six (17%) cases, all of which had primary neoplasms more than 3 mm thick. The most superficial lesion to have lymph node metastasis was 3.2 mm thick and had 1.6 mm of stromal invasion. Nonetheless, depth of stromal invasion of less than 3 mm was associated with statistically fewer lymph node metastases (7%) than that of neoplasms with 3 mm or more of stromal invasion (50%). Although lymphatic or blood capillary invasion was present in four (11%) cases, this feature had no statistically significant association with lymph node metastasis. There was no relationship between clinical stage, surface diameter, or histological grade of the lesion and lymph node metastasis. A significant percentage of cases had either carcinoma in situ (31%) or atypical hypertrophic dystrophy (19%) in the epithelium adjacent to the infiltrating carcinoma. Koilocytotic atypia suggestive of human papilloma virus infection was present in the adjacent epithelium in 47% of the cases. This study suggests that thickness of the neoplasm is a valid predictor for the presence or absence of lymph node metastasis in vulvar squamous cell carcinoma; it may be more useful than neoplastic depth of invasion in this regard.

Carcinoma in Situ↗
PubMed1983

Do preoperative laboratory tests predict blood transfusion needs in cardiac operations?

We retrospectively compared preoperative prothrombin (PT), partial thromboplastin (PTT), dilute whole blood clot lysis and bleeding times, fibrinogen level, and platelet count with subsequent blood component administration in 92 patients who had undergone cardiac operations with cardiopulmonary bypass (CPB). Abnormal results for one or more tests were found in 34% of 71 adults and 81% of 21 children and teenagers. The patients with abnormal test(s) received no more whole blood and packed red cell units, platelets, or plasma than those with normal tests in either age group. No individual or multiple test abnormalities predicted excess blood component transfusion, even when low-grade abnormalities were excluded. The high rate of abnormal tests in patients less than 20 years of age was not due to polycythemia and may indicate a need for age-specific reference ranges. Baseline PT, PTT, and platelet count may aid in the evaluation of the potential for subsequent development of coagulopathy, but we conclude that further preoperative testing may be reserved for infants, polycythemic individuals, or others in whom history or drug use suggests potential bleeding problems.

Adolescent↗
PubMed1974

Analysis of the growth of recombination-deficient strains of Escherichia coli K-12.

Cultures of recombination-deficient strains of Escherichia coli are composed of three classes of cells: (i) viable cells, which can undergo 20 or more generations, (ii) residually dividing cells, which can undergo fewer than 20 generations (probably an average of fewer than 6), and (iii) nondividing cells, which are incapable of a single division. The nonviable but residually dividing cells contribute to the mass increase of the culture, but not to the viability, thus accounting for the apparent dissimilarity in the effects of rec mutations on growth rates and viabilities. We have determined the frequencies of cells in each of the three classes, and, by making a simplifying assumption concerning the relative division times of viable and residually dividing cells, we have been able to describe mathematically the growth of the rec(-) cultures.

Bacteriological Techniques↗
PubMedDate not supplied

Frequency of PLA1 in blacks.

Racial frequencies of platelet-specific antigens in racial groups other than whites have not been studied. The prevalence of PLA1 was determined in white and black blood donors. Two hundred forty-two of 243 blacks were PLA1-positive (99.6%), compared with 242 of 250 whites (96.8%) (p = 0.021). This black population has the highest frequency of PLA1 yet reported.

Antigens, Human Platelet↗
PubMedDate not supplied

Loss of red cell alloantibodies over time.

The loss of red cell alloantibodies over time was analyzed in 160 patients with 209 antibodies retested 1 to 60 months after initial identification. The mean follow-up consisted of 3.6 specimens taken over 18 months. Twenty-nine percent of clinically significant and 72 percent of clinically insignificant antibodies were not detected on at least one follow-up screening. Anti-Jka and anti-C were lost in 59 and 45 percent of cases, respectively. No significant differences in overall antibody loss were found according to sex, diagnosis, or the presence of multiple antibodies. Patients under 20 years of age may be more likely to lose significant antibodies. Pretransfusion review of previous records is vital for the prevention of delayed hemolytic transfusion reactions, because of the high number of clinically significant antibodies that are undetected in subsequent routine screening.

Adult↗
PubMedDate not supplied

Red cell alloimmunization in multitransfused HLA-typed patients.

The authors studied retrospectively the formation of clinically significant red cell (RBC) alloantibodies in 958 HLA-typed, multiply transfused patients receiving kidney (603 patients) or liver (263 patients) transplants or plateletpheresis transfusions (92 patients). RBC alloantibodies were found in 91 (9.5%) of these patients and multiple antibodies in 35 (3.7%). Rh (D, C, c, and E) antibodies accounted for 49 percent of the total and Kell antibodies for 31 percent. Antibodies were found in 15 percent of apheresis recipients and in 8.6 percent of renal and 9.5 percent of liver transplantation patients. No association was found between any HLA-A, HLA-B, or HLA-DR phenotype and the presence of RBC alloantibodies, either in general or when analyzed according to the specific antibody. Renal transplant patients with RBC alloantibodies were somewhat more broadly HLA-alloimmunized than were those without RBC alloantibodies. Patient gender did not affect these results. The authors concluded that the immune response to RBC alloantigens is independent of HLA type but is associated with an increased level of HLA antibody formation.

Adolescent↗
PubMedDate not supplied

The type and screen: are patient charges a valid measure of cost reduction?

Previous studies of the type and screen have employed reduction in patient charges as a measure of cost savings. Actual cost reductions were estimated as well as patient charge reductions, for the type and screen in a large university medical center with 38,519 cross-matches and 18,152 red cell containing transfusions (C/T = 2.12) in 1980. If the type and screen had been implemented for elective surgical procedures with C/T greater than 2, the C/T for these services would have fallen from 2.82 to 2.17. If use of the type and screen were extended to obstetrics patients, the total surgical and obstetrical patient charges would be reduced by $51,752, but only $9,232 or less in actual cost reduction would have accrued. The type and screen does not lead to significant decreases in labor or overhead costs which are the largest component of patient charges. Patient charge savings are not a valid measure of actual cost reduction in our setting.

ABO Blood-Group System↗