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M R Williams

Publications and source records attributed to M R Williams.

97 records · Page 6Linked to original sources
PubMed1975

Quantitative studies on bovine immunoglobulins, normal plasma levels of IgG2, IgG1, IgM and IgA.

Using monospecific sheep antisera, the mean plasma immunoglobulin concentrations in 82 Ayrshire milking cows were found, by the single radial diffusion method, to be: IgG2 10-91 plus or minus 4-30, IgG1 9-76 plus or minus 2-59 and IgM 2-71 plus or minus 1-22 mg/ml (plus or minus SD). IgA levels in the same group of 82 cows were determined by a simple, sensitive coated tube radioimmunoassay and had a mean value of 0-32 plus or minus 0-16 mg/ml. The frequency distributions of IgG1, IgM and IgA were approximately log normal, whereas that of IgG2 was bimodal with two populations with means of approximately 7 and 14 mg/ml. An 18-fold difference was found between high and low IgG2 levels whereas only three- to four-fold differences were recorded for IgG1 levels in the same population. Eight-fold differences were found for IgM and IgA levels. The effect of age (2-9 years) on sampling could be disregarded for IgG1, IgG, IgM and IgA levels, but cows above 6 years of age had significantly higher IgG2 levels.

Age Factors↗
PubMedDate not supplied

Precipitation and river water chemistry of the Piracicaba River basin, southeast Brazil.

Annual precipitation and river water volumes and chemistry were measured from 1995 to 1998 in a mesoscale agricultural area of southeast Brazil. Precipitation was mildly acidic and solute concentrations were higher in the west than in the east of the basin. Combustion products from biomass burning, automobile exhaust, and industry typically accumulate in the atmosphere from March until October and are responsible for seasonal differences observed in precipitation chemistry. In river waters, the volume-weighted mean (VWM) concentrations of major solutes at 10 sites across the basin were generally lower at upriver than at downriver sampling sites for most solutes. Mass balances for major solutes indicate that, as a regional entity, the Piracicaba River basin was a net sink of H+, PO4(3-), and NH4+, and a net source of other solutes. The main stem of the Piracicaba River had a general increase in solute concentrations from upriver to downriver sampling sites. In contrast, NO3- and NH4+ concentrations increased in the mid-reach sampling sites and decreased due to immobilization or utilization in the mid-reach reservoir, and there was denitrification immediately downriver of this reservoir. Compared with tributaries of the Chesapeake Bay estuary, the Piracicaba River is affected more by point-source inputs of raw sewage and industrial wastes than nonpoint agricultural runoff high in N and P. Inputs of N and C are responsible for a degradation of water quality at downriver sampling sites of the Piracicaba River drainage, and water quality could be considerably improved by augmenting sewage treatment.

Acid Rain↗
PubMedDate not supplied

Gender differences in patients undergoing coronary artery bypass surgery, from a mandatory statewide database.

OBJECTIVE: To determine why women have a higher mortality rate than men when undergoing coronary artery bypass grafting. DESIGN: Retrospective analysis of patients entered in a mandatory state database. PARTICIPANTS: 19,224 patients who underwent coronary artery bypass grafting in New York State in 1995. METHOD: The authors evaluated data pertaining to 27 variables. They conducted univariate analysis using the Student t test for continuous variables and the chi-square test or the Fisher exact test for discrete data. They conducted multivariate analysis using a logistic regression model. RESULTS: Analysis of body surface area revealed that smaller size was a risk factor for both women and men. Analysis of age demonstrated increased risk for mortality in women in both older and younger subpopulations. Other significant variables included a lesser degree of revascularization and less frequent use of the internal mammary artery in women. CONCLUSION: Smaller size and advanced age alone do not explain why female gender is an independent risk factor for mortality from coronary artery bypass grafting. Increased mortality is probably due to the fact that women have more comorbid conditions than men at the time of referral, perhaps because they are not being evaluated aggressively enough.

Adult↗