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Biomedical subjects

M Peacock

Publications and source records attributed to M Peacock.

At least 19 recordsLinked to original sources
PubMed1979

Plasma 25-hydroxyvitamin D in pregnant Asian women and their babies.

Plasma 25-hydroxyvitamin D (25-OHD) was measured in cord blood taken at delivery and in fasting blood taken from 44 Asian mothers in the first day of the puerperium. Blood was taken from the baby 48 h after delivery. Cord-blood samples were also taken at 43 non-Asian deliveries. Plasma 25-OHD concentrations in Asians were low at delivery; in 81% of the mothers and 36% of the babies plasma 25-OHD was in the osteomalacic range. Asian lower than concentrations in non-Asian controls. 4 Asian babies had vraniotabes and 1 had neonatal tetany. 1 non-Asian baby had craniotabes. A review of 3327 deliveries in 1978 confirmed that neonatal tetany was significantly more common in Asian babies (2.3%) than in non-Asian babies (0.3%). In 44 other Asian mothers supplements of 1000 units of vitamin D daily during pregnancy significantly increased plasma-25-OHD concentrations at delivery.

Asia↗
PubMed1979

The effect of high animal protein intake on the risk of calcium stone-formation in the urinary tract.

1. Studies were carried out on six normal male subjects to determine the short-term effect of increasing the dietary consumption of animal protein on the urinary risk factors for stone-formation, namely, volume, pH, calcium oxalate, uric acid and glycosaminoglycans. 2. An increase of 34 g/day of animal protein in the diet significantly increased urinary calcium (23%) and oxalate (24%). Total urinary nitrogen increased by an average of 368 mmol/day. The accompanying increase in dietary purine (11 mmol of purine nitrogen/day) caused a 48% increase in the excretion of uric acid. 3. The overall relative probability of forming stones, calculated from a combination of the risk factors, was markedly increased (250%) throughout the period of high animal protein ingestion.

Adult↗
PubMed1979

Should recurrent calcium oxalate stone formers become vegetarians?

The hypothesis that the incidence of calcium stone disease is related to the consumption of animal protein has been examined. Within the male population, recurrent idiopathic stone formers consumed more animal protein than did normal subjects. Single stone formers had animal protein intakes intermediate between those of normal men and those of recurrent stone formers. A high animal protein intake caused a significant increase in the urinary excretion of calcium, oxalate and uric acid, 3 of the 6 main urinary risk factors for calcium stone formation. The overall relative probability of forming stones, calculated from the combination of the 6 main urinary risk factors, was markedly increased by a high animal protein diet. Conversely, a low animal protein intake, such as taken by vegetarians, was associated with a low excretion of calcium, oxalate and uric acid and a low relative probability of forming stones.

Calcium↗
PubMed1979

Q fever endocarditis in the United States.

A patient with Q fever endocarditis, which is almost unknown in the United States, was followed for a total of 32 months; the study was begun 3 1/2 months before aortic valve replacement. Diagnosis was confirmed by serology, visualization of Coxiella burnetii in excised aortic valve tissue by direct and immunofluorescence staining, and isolation of C. burnetii from aortic valve tissue. Serum antibodies against phase I and phase II antigens of C. burnetii were identified. Almost all phase I and phase II antibodies were IgG. These findings are compared with those in an uncomplicated case of acute Q fever. New findings on the immune response to chronic Q fever are presented.

Animals↗
PubMed1979

Urinary tract stone disease.

Patients suffering from urinary stone are traditionally referred to a surgeon. Most are investigated only as far as establishing the site of the stone and its effect on renal function. Although a number of patients may require surgery, the majority pass the stone spontaneously and are discharged within a few days. If the patient has a recurrence, as most eventually have, it is not routine practice to establish the type of stone, screen for underlying disease, identify the urinary abnormalities or to institute preventive medical treatment. Although it was considered that surgery itself had something to offer in reducing the recurrence rate this is no longer generally held except in infected stone disease. Nevertheless it is still uncommon to involve a physician, and in particular a nephrologist, in the investigation and management of urinary stone-formers. Urinary stone disease still remains, to a large extent, outside the field of nephrology.

Bacterial Infections↗
PubMed1978

Risk factors in calcium stone disease of the urinary tract.

The concept that calcium stone formation may be explained on the basis of a number of risk factors is developed. The main risk factors involved are shown to be calcium, oxalate, pH, acid mucopolysaccharides and uric acid. A method is described for calculating and combining the individual risk factors into a measure of the "relative probability" of forming stones (PSF). PSF values are generally lower in normal subjects than in stone-formers. Amongst the normals, PSF values are lower in children and women than in men. Recurrent stone-formers have the highest PSF values and these correlate well with the severity of the diseases as defined by the stone episode rate of the patient. Single stone-formers have PSF values intermediate between those of normal men and those of recurrent stone-formers.

Adult↗
PubMed1978

Limits of rickettsial infectivity.

Seven species of pathogenic rickettsiae were compared in five assay systems for group, species, strain, and phase differences in infectivity. The species examined include Rickettsia prowazekii (Breinl and Cairo 3 strains), R. typhi, R. canada, R. rickettsii (Sheila Smith and R strains), R. conorii, R. sibirica, and Coxiella burnetii in phases I and II. Pathogenicity was charcterized in terms of fever in guinea pigs. All comparisons of infectivity and pathogenicity were described in terms of numbers of rickettsiae in the inocula, as determined by direct rickettsial count. The data characterize the various species and strains of rickettsiae in quantitative terms, which are also estimates of the sensitivity of the assay systems used. Phase I C. burnetii was found to be the most, and R. canada the least, infective of the species examined. In general the primary chicken embryo cell culture system proved to be the most, and that of the mouse the least, sensitive assay system.

Animals↗
PubMed1978

The stabilization of morphological field size during slime mold morphogenesis.

The relationship between aggregate size and morphological field size has been investigated in the cellular slime mold Dictyostelium discoideum. Evidence is presented that aggregate size and field size exhibit different temperature sensitivities and that an aggregate can be induced to separate into several morphological fields by a decrease in temperature. In addition, evidence is presented that field size is stabilized at a point in time just prior to tip formation.

Cell Count↗
PubMed1978

Antigenic relationships between the typhus and spotted fever groups of rickettsiae.

Paired sera from cases of epidemic typhus in Ethiopia and from probable cases of Rocky Mountain spotted fever (RMSF) in the United States were examined by microagglutination (MA) and microimmunofluorescence (micro-IF) tests for antibodies against Rickettsia prowazekii, Rickettsia typhi, Rickettsia canada, Rickettsia rickettsii, Rickettsia conorii and Ricksettsia akari. IgG and IgM antibodies against the various rickettsiae were titrated with specific fluorescein-conjugated anti-IgG and anti-IgM sera. Purified, particulate rickettsial antigens were employed in all tests. A majority of patients acutely ill with epidemic typhus produced both IgG and IgM antibodies against R. prowazekii, R. typhi and R. canada. Concurrently they produced IgG (but seldom IgM) antibodies against members of the spotted fever group. In contrast, patients ill with probably spotted fever, while producing IgG and IgM antibodies against R. rickettsii, R. conorii and R. akari, also produced both IgG and IgM antibodies with about equal frequency against members of the typhus group. It was concluded that a relatively broad antigenic relationship exists between rickettsiae of the typhus and spotted fever groups.

Agglutination Tests↗