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Biomedical subjects

W D Morgan

Publications and source records attributed to W D Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1980

In vivo measurement of critical level of kidney cadmium: dose effect studies in cadmium smelter workers.

In vivo measurements of kidney and liver cadmium burdens were obtained in 82 industrially exposed workers and ten control subjects. Kidney cadmium levels ranged from 0.9 mg to 57 mg, and liver concentrations ranged from 0.8 ppm to 120 ppm for the industrial group. Comparison values for the control group were 0.4 mg to 11.8 mg for the kidney and 0.6 ppm to 7.9 ppm for the liver. A biphasic relationship between kidney Cd levels and liver Cd levels was observed. The kidney and liver Cd levels showed an increase until approximately a 40 ppm concentration was reached in the liver. Thereafter, the kidney levels decreased as the liver concentration continued to increase. The kidney cadmium level at which this change occurred was approximately 31 mg for the total kidney. Further estimates of the critical level, based on years of exposure and renal dysfunction (beta 2-microglobulin, proteinuria), yielded estimates of 31 mg to 42 mg cadmium (300-400 micrograms/gm for the renal cortex).

Cadmium↗
PubMed1980

An in-vivo study of renal cadmium and hypertension.

A comparative study of renal cadmium burdens in a group of thirty hypertensive patients undergoing treatment and in a group of thirty matched controls is reported, both groups being volunteers selected from a non-occupationally exposed population. The aim of this study was to investigate the possible involvement of cadmium in the aetiology of hypertension at the chronic low levels of environmental exposure. Renal cadmium levels were measured in vivo, using the technique of partial-body neutron activation analysis. The results showed that the mean renal cadmium level in the hypertensive group [3.3 mg (SD 2.3)], was not significantly different from that [4.4 mg (SD 2.7)], in the normotensive group. Whether the level in the hypertensives depends on the treatment is open to question and will be the subject of further investigation. In addition, the results confirm that kidney cadmium levels are elevated in smokers.

Cadmium↗
PubMed1979

Microcinematographic demonstration of synchronous and asynchronous myoepithelial contractions in mouse submandibular gland rudiments in organotypic culture.

Time-lapse phase-contrast cinematography revealed contractile activity within mouse submandibular salivary gland rudiments in organotypic culture. Three types of contraction were distinguishable. In type I (voiding contractions), all portions of the gland contracted synchronously, and the active state ranged from 30 min to 2 hr. In type II (priming contractions), all portions of the gland contracted synchronously, but the active state was shorter, ranging from 4 to 10 min. In type III (churning contractions), isolated foci in lobules or secretory units throughout the gland contracted asynchronously and had very short active states of about 1 min. By electron microscopy, myoepithelial cells could first be demonstrated in submandibular glands developing either in vitro or in vivo, at 21 days postconception. Contractions in the cultured rudiments began as early as 18 days postconception. Since neither smooth nor striated muscle could be identified in these glands by electron microscopy, the contractions are believed to result from myoepithelial activity that apparently may begin before ultrastructural evidence of myoepithelial differentiation is clearly present. Although, for over a century, myoepithelium has been presumed to have a contractile function and indirect evidence has lent ample support to this presumption, the present study represents the first direct cinematographic demonstration and characterization of myoepithelial contractions, under conditions in vitro.

Animals↗
PubMed1971

Epithelial origin of polyoma salivary tumors in mice: evidence based on chromosome-marked cells.

Trypsin dissection of epithelium from mesenchyme of salivary gland rudiments allows reassembly of glands having either epithelium or mesenchyme selectively marked by T(6) chromosomes. Virus-induced tumors in such glands invariably bear the karyotype of the epithelial component. The method solves a specific example from a group of classical problems concerning epithelial as opposed to mesenchymal origin of neoplasms.

Aneuploidy↗
PubMedDate not supplied

In vivo measurements of cadmium and lead in occupationally-exposed workers and an urban population.

This paper reports the preliminary findings of a survey of lead and cadmium body burdens in a nonoccupationally exposed population in Swansea, Wales, using the techniques of in vivo neutron activation and X-ray fluorescence analysis. Some measurements on an occupationally cadmium-exposed group are also included. The results confirm the association between cadmium and smoking and bone lead and age. The in vivo measurements demonstrate a degree of comparability with other data, which supports the further detailed analysis of the relationships between body burden and exposure, on the one hand, and possible health effects on the other.

Adult↗
PubMedDate not supplied

Measurements of total body calcium by prompt-gamma neutron activation analysis using a 252Cf source.

A clinical neutron activation instrument has been developed for in vivo elemental analysis. Utilizing the prompt-capture gamma ray technique, simultaneous total body (TB) measurements of primarily Ca, but also Cl, N, C, and H are routinely performed. This paper describes a technique for the measurement of TBCa (g) that relies on the use of TBCl as an internal standard. The method has been tested with four anthropomorphic phantoms covering a range of body habitus. The mean discrepancy between the measured and known Ca contents was 3.6%. The technique has been applied to two patient groups, and encouraging results were obtained.

Body Composition↗
PubMedDate not supplied

Longitudinal measurements of the cadmium burden of 'jig solderers' using IVNAA.

The liver and kidney cadmium burdens of a population of 10 'jig solderers' were measured in 1983 and 1995 using similar IVNAA measuring systems. Cadmium exposure ceased in 1985. No significant variation in kidney content was observed. The mean body burden had fallen by 18%, due to a decrease of mean liver content of 35%.

Cadmium↗