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Biomedical subjects

M A Baird

Publications and source records attributed to M A Baird.

47 records · Page 3Linked to original sources
PubMed1982

Major histocompatibility complex-linked spleen-dependent transfusion "collapse curves" in inbred rats.

In most donor-host combinations among seven inbred rat strains, transfused allogeneic red blood cells were cleared from the circulation of unsensitized hosts at a rate no different from that of syngeneic red blood cells. In four strain combinations, however, allogeneic red blood cells were cleared very rapidly, and in six combination, clearance was effected at a rate intermediate between the rapid clearance rate and the syngeneic rate. In strain combinations exhibiting rapid clearance, females cleared allogeneic red blood cells significantly more rapidly than did males. Rapid clearance was linked to the major histocompatibility complex (MHC) of the donor strain but not to the MHC of the host strain. All donor-host combinations showing rapid clearance possessed identical RT2, RT3, and AgS red blood cell alloantigens. Red blood cells removed rapidly from the circulation by allogeneic hosts were sequestered in the spleen rather than lysed in the circulation. The phenomenon was mediated by splenic reticuloendothelial cells and could be completely circumvented by prior splenectomy. Rapid clearance was apparently not antibody mediated. The phenomenon of rapid clearance of allogeneic red blood cells in rats appears to be analogous to the "collapse curves" of human blood transfusion.

Animals↗
PubMed1981

Characterization and intermethod relationships of materials containing purified human pancreatic and salivary amylase.

We describe the preparation and characterization of materials containing human pancreatic and salivary alpha-amylase (EC 3.2.1.1) and examine their relationship to endogenous amylase in human serum. Amylase was purified from human pancreas and saliva by solvent- and salt-fractionation and column chromatography to specific activities of 63 and 279 kU/g, respectively. Four liquid pools, differing only in activity, were prepared from each source of amylase, each in a matrix containing, per liter: 30 g of human albumin, 50 mmol of sodium chloride, 1 mmol of calcium chloride, and 50 mmol of Tris hydrochloride buffer, pH 7.4. Characterization of the pools showed that the amylase activity in the materials was stable for at least six months at 25 degrees C; among-vial variability of amylase activity was less than or equal to 0.5% (2 CV); and the pools were free from eight possible contaminating enzymes. Plots of salivary vs pancreatic amylase activity measure in our materials with eight commercially available methods showed least-squares slopes ranging from 0.51 to 1.0. The intermethod "commutability" of the materials (i.e., how closely they mimic endogenous serum amylase) was examined in relationship to approximately 100 human sera.

Amylases↗
PubMed1980

A coupled-enzyme equilibrium method for measuring urea in serum: optimization and evaluation of the AACC study group on urea candidate reference method.

We describe a coupled-enzyme equilibrium method for measuring urea in serum, which is performed on supernates prepared by treating each specimen with Ba(OH)2 and ZnSO4 (Somogyi reagent). Analytical recovery of [14C]urea added to a variety of matrices was essentially complete (mean, 100.6%) for the supernates after precipitation. Nine variables were univariately examined in arriving at the reaction conditions for the method: glutamate dehydrogenase, urease, 2-oxoglutarate, ADP, Tris . HCI, NADH, EDTA, pH, and temperature. The reagent is stable for at least 48 days at--20 degrees C and for 23 days at 4 degrees C. Mean analytical recovery of urea (14 mmol/L) added to seven different specimens (three different matrices) was 100.8%. The analytical linear range of the method extends to 30 mmol of urea per liter. Of 22 potential interferents, only bilirubin at 1 mmol/L (580 mg/L), hemoglobin at 10 g/L, and hydroxyurea at 6 mmol/L showed more than 2% interference. We discuss precision and effects of specimen dilution, and compare results for 100 human serum specimens with those measured for the same specimens with four other urea methods. We examined the effects of measuring a blank, consisting of sample and reagent without urease, with each specimen.

Animals↗
PubMed1979

Chemical inhibition used in a kinetic urease/glutamate dehydrogenase method for urea in serum.

We describe a fixed-time-interval, kinetic inhibition method, with use of a competitive inhibitor (l) of the urease/glutamate dehydrogenase reaction to increase the "apparent" Michaelis constant by a factor of (1 + [l]lKl). This allows greater flexibility in selecting an appropriate sample dilution for kinetic determinations of urea in serum (i.e., [S]lKm ratio). Nine compounds were screened as potential inhibitors for this study. Adding 5 mmol of hydroxyurea per liter increases the "apparent" Michaelis constant for the coupled enzyme reaction by 10-fold. We used a sample dilution of 21-fold vs. dilutions of 141- to 350-fold for previously reported kinetic methods. Mean analytical recovery with this method was 100.2%. Reaction rate vs. urea concentration was linear, and complete recovery extended to 30 mmol of urea per liter. Of 22 potential interferents, only fluoride (250 mmol/L) and bilirubin (1 mmol/L, or 580 mg/L) caused greater than 5% interference. We discuss precision and effects of specimen dilution, and compare results for 100 specimens with those by a manual Berthelot-indophenol method, a manual diacetyl monoxime method, and a diacetyl monoxime method adapted to continuous-flow analysis.

Autoanalysis↗
PubMed1977

Temperature dependence of the absorbance of alkaline solutions of 4-nitrophenyl phosphate--a potential source of error in the measurement of alkaline phosphatase activity.

The absorbance of an alkaline solution of 4-nitrophenyl phosphate is a function of temperature. Quantitative evaluation of this phenomenon indicates that it (a) depends on the concentration of the compound and is independent of source, buffer concentration, and pH above 9.0; (b) is reversible; (c) is not a result of alkaline hydrolysis or 4-nitrophenol contamination; and (d) correlates with a temperature-induced shift of its absorbance spectrum. The phenomenon may represent a potential analytical problem in methods for alkaline phosphatase in which this compound is the substrate. If thermal equilibrium is not reached and maintained during an alkaline phosphatase assay, the thermochromic response will be included in the measured rate. The magnitude of this error depends on the thermal response and control characteristics of each particular instrument and the reaction conditions under which such an analysis is performed.

Alkaline Phosphatase↗
PubMed1976

Morbidity of therapeutic abortion in Auckland.

Twenty-six women were admitted to National Women's Hospital with complications following therapeutic abortion at the Auckland Medical Aid Centre, during its first year of operation. This represents 1.4 percent of the total number of cases at the Centre that year. The principal early complicatons were pelvic sepsis, suspected uterine perforation and incomplete abortion. The complication rate appears to be low and compares favourably with reports from other centres. During the same period, 17 women (8.4 percent) whose pregnancies were terminated at National Women's Hospital had significant complications. All 43 complicated cases are analysed.

Abortion, Therapeutic↗
PubMedDate not supplied

Risks and benefits of a family systems approach to medical care.

The "art of medicine" is struggling for survival in medical education, practice, and research. The authors embrace the biopsychosocial model as an ideal new paradigm for medicine and propose that the family systems approach provides the best available vehicle for applying the biopsychosocial model to everyday medical practice and research. Such an approach would require major changes in the way health care is delivered and offers both benefits and risks for family physicians to consider. One important change would involve the sharing of physicians' power in a health care system that emphasizes collaboration among individuals, families, and a variety of professionals. Such revolutionary changes should be approached with caution.

Family↗
PubMedDate not supplied

Developmental levels in family-centered medical care.

This paper describes a developmental sequence which many physicians seem to experience as they mature in their competence in family-centered medical care. The flow of the developmental levels is from information to affect to social systems. The paper concludes with implications for family systems curricula in family medicine residencies.

Curriculum↗