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Biomedical subjects

I Young

Publications and source records attributed to I Young.

At least 73 records · Page 4Linked to original sources
PubMed1985

Effects of ketoconazole on rat testicular steroidogenic enzymatic activities.

Ketoconazole (K) is an antifungal imidazole derivative which has been shown to be a potent inhibitor of testosterone (T) biosynthesis in rodents and humans. To study the effect of K on rat testicular steroidogenesis we measured the activities of five testicular microsomal steroidogenic enzymes in K-treated rats and controls. Thirty male adult rats were given either 2 mg K or water every 12 hours by mouth during 5 days. Mean testicular weight was similar in both groups of animals. The K-treated group had a T serum concentration of 83 +/- 14 ng/dL whereas it was 94 +/- 16 ng/dL in the control group (NS). The K-treated animals had decreased activities of the 3 beta-hydroxysteroid dehydrogenase (830 +/- 48 vs 2,245 +/- 109 pmol/mg protein/min, P less than 0.001), 17-hydroxylase (243 +/- 5 vs 676 +/- 17 pmol/mg protein/min, P less than 0.001), 17-ketosteroid reductase (31 +/- 2 vs 169 +/- 7 pmol/mg protein/min, P less than 0.001), and aromatase enzymes (92 +/- 6 vs 123 +/- 7 pmol/mg protein/min, P less than 0.01). The 17,20-desmolase activity was similar in both groups of animals (210 +/- 4 vs 171 +/- 18 pmol/mg protein/min). We conclude that K given orally to rats inhibits the activity of several testicular steroidogenic enzymes.

17-Hydroxysteroid Dehydrogenases↗
PubMed1985

Nucleoside transport and cytosine arabinoside (araC) metabolism in human T lymphoblasts resistant to araC, thymidine and 6-methylmercaptopurine riboside.

Alteration in cellular nucleoside transport characteristics, deoxynucleoside triphosphate (dNTP) pools and araCTP formation from cytosine arabinoside (araC) were determined for human T lymphoblasts (CCRF-CEM) resistant to araC, thymidine or 6-methylmercaptopurine riboside (6-MMPR). AraC resistance was accompanied by reduced activities of deoxycytidine and thymidine kinases, lowered cellular deoxycytidine triphosphate concentration and markedly reduced formation of araCTP from araC. The ID50 values for araC, araCTP formation and dNTP levels of thymidine-resistant lymphoblasts, which exhibited reduced thymidine kinase activity, and 6-MMPR-resistant cells, with reduced adenosine kinase activity, were similar to the corresponding parameters of wild type lymphoblasts. The nucleoside transport sites density determined by nitrobenzylmercaptopurine riboside binding was comparable for araC-resistant, wild type and thymidine- or 6-MMPR-resistant lymphoblasts.

Adenosine Kinase↗
PubMed1985

Immunoglobulin G (IgG) levels in breast tumor cytosols.

Immunonephelometer investigation of specific proteins revealed a difference in levels of immunoglobulin G (IgG) found in the cytosol of estrogen receptor (ER) rich and estrogen receptor poor tumor tissue. Cytosols from estrogen receptor poor tumors had a significantly higher level of IgG than those from estrogen receptor rich tissues. The relationship between progesterone receptor levels and IgG was not as significant as that observed between ER levels and IgG. Other specific proteins did not correlate with either estrogen receptor levels or progesterone levels.

Breast Neoplasms↗
PubMed1984

Gas exchange.

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Blood Gas Analysis↗
PubMed1982

Distribution of specific ventilation in cystic fibrosis.

Continuous distributions of specific tidal ventilation were recovered from nitrogen washouts in 29 patients with cystic fibrosis and 22 normal subjects along with other pulmonary parameters to assess the utility of the recovered distribution in describing the progress of the disease. Normal subjects showed predominantly unimodal distributions of a pattern showing a small amount of ventilation going to units with high specific ventilation. Multimodal distributions were the rule in the cystic population with only subjects with normal pulmonary function having unimodal distribution.

Adolescent↗
PubMed1981

Prevalence of asbestos related lung disease among employees in non-asbestos industries.

Employees from two non-asbestos industries wee examined to assess the prevalence of asbestos-related lung disease. Of the 214 employees, one suffered from a malignant mesothelioma of the pleura and in 13 (6.1%), pleural plaques were diagnosed radiologically. the plaques were symptomless and not associated with any disturbance in respiratory function. The sole source of asbestos fibre in one factory was the asbestos insulation surrounding steam and hot water pipes similar to that found throughout industry. Exposure occurred as the result of the way in which this insulation has been handled routinely in industry by people who have commonly been unaware either of their exposure or of its significance. In the second factory there was the possibility of additional exposure originating from a neighbouring industry that was a major consumer of asbestos. The results suggest that maintenance workers may be particularly at risk and that the presence of pleural plaques may be under-reported in the absence of a history of asbestos exposure to direct attention towards them. The presence of pleural plaques has important consequences for the individual and for others who have shared the work environment.

Adult↗
PubMed1980

Chronic respiratory disease and respiratory function in a group of fire fighters.

A sample of 193 subjects drawn from the New South Wales Fire Brigade was studied to examine the prevalence of chronic respiratory disease and impairment of respiratory function. The prevalence of respiratory disease was less than that reported in other groups of firemen and reflects the lower level of occupational exposure, and possibly a survivor effect, within the New South Wales Fire Brigade. Among recent recruits, the effects of cigarette smoking far outweighed any contribution from occupational exposure. Among firemen with 20 years or more service a twofold increase in the prevalence of chronic bronchitis is considered to result from the additive effects of cigarette smoking and the high occupational smoke exposures consequent to the availability of respiratory protection and earlier attitudes to its use. The increasingly toxic nature of combustion products at fires was not accompanied by a discernible increase in the prevalence of chronic respiratory disease or impairment of respiratory function. The major combustion products responsible for respiratory damage were self-administered, arising from burning tobacco rather than from burning buildings.

Adult↗
PubMed1980

Identification of functional lung unit in the dog by graded vascular embolization.

To study the dimensions of the functional gas exchange unit, spherical polystyrene beads (diam 50-500 micrometers) were injected intravenously into 12 normal anesthetized paralyzed dogs (15-24 kg wt). We argued that beads small enough to lodge within gas exchange units would not give rise to a population of high ventilation-perfusion ratio (VA/Q) areas, whereas embolization of larger vessels supplying these units would. Each dog received only one bead size in cumulative 0.25-g doses up to a maximum of 2.25 g. Multiple inert gas elimination data were obtained after each dose to monitor the development of high VA/Q regions. Injection of 50- and 100-micrometers beads never gave rise to high VA/Q regions, whereas 150-, 250-, and 500-micrometers beads consistently induced a high VA/Q mode comprising up to 45% of the ventilation. Histological examination of lungs from five additional dogs injected with small (approximately 0.5 g) doses revealed that beads rarely formed clusters and appeared in vessels of their own diameter in over 90% of instances. By the above criterion, the functional gas exchange unit in these lungs is that volume of tissue subtended by 150- micrometers-diam arteries (vessels associated with respiratory bronchioles).

Animals↗
PubMed1979

Pleomorphic pulmonary hamartoma: an apparently unique variant of pulmonary hamartoma.

Pulmonary hamartomas of limited variety have been described. Most present as asymptomatic coin lesions in adults and consist of mesenchymal tissue, usually cartilage, in combination with irregular spaces lined by epithelium. Another form is found in the neonate and involves large portions or all of a lung. This is associated with a developmental aberration and is best described as a "congenital adenomatoid malformation". An apparently unique noninvasive tumor mass was resected from the lung of a middle aged man where it was associated with anomalous lung segmentation and the bronchial and blood supply to the lung. The tumor appeared to be undifferentiated by light microscopic criteria. Neurilemoma, leiomyoma, chordoid tumor, mixed tumor, and neurogenic sarcoma all entered the differential diagnosis. Ultrastructural examination demonstrated a highly complex and unique organization. Such a lesion, apparently developmental in this case, should be recognized and carefully distinguished from the malignant mesenchymal, neurogenic, and teratomatous lesions with which it may be confused. Electron microscopy may be helpful in this regard.

Adult↗
PubMed1979

An interactive computer system for the analysis of cell lineages.

We have developed an interactive computer system for analysing cell lineage data. It can be utilized in studies of cell motility, cell division, cell differentiation, and cell aging. It has enabled us to document the heterogeneity of human foreskin fibroblasts in culture and to propose that loss of proliferative potential may mean that cells enter a state of differentiation which makes them unable to respond to mitotic stimulation. Our method, which enables us to apply immunological and cytochemical probes after recording the history of a cell lineage, should allow us to define precisely features which uniquely distinguish cycling from noncycling cells on an individual cell basis.

Cell Cycle↗
PubMed1978

Familial neurodegenerative disorder associated with raised urinary vanillylmandelic acid.

We report a child who presented with a progressive neurological disorder associated with hypertension and paroxysms of irritability and sweating in whom an abnormality of catecholamine metabolism or excretion was demonstrated. An elder sister died at the age of 2 1/2 years with similar clinical symptoms but without blood pressure or catecholamine excretion being recorded. The exact mechanism of the disturbance of catecholamine excretion was not identified in our patient but some slight improvement in hypertension and arrest of his neurological deterioration was noted when he was put on a low tyramine diet. It is suggested that our patient may well suffer from a familial neurodegenerative disorder in which an abnormality of catecholamine metabolism or excretion is a feature.

Humans↗
PubMed1978

Mycosis fungoides-like cells. Their presence in a case of pityriasic dermatitis with a comment on their significance as an indicator of primary T-cell dyscrasia.

A case of pityriasic dermatitis in which the histologic findings mimicked mycosis fungoides was examined ultrastructurally. Large numbers of mycosis-like cells were found in the dermis and within epidermal spongiotic vesicles. Such cells occur in the epidermal and dermal infiltrates of primary T-lymphocyte disorders, notably in mycosis fungoides, the Sézary syndrome, and parapsoriasis en plague. However, they have also been found in the dermal infiltrates of benign dermatoses, in some skin tumors, and occasionally in normal controls. They share ultrastructural features with transformed T lymphocytes. It is emphasized that cells with this morphology may be found in the skin in any condition involving T-cell transformation or dysplasia. The mere presence of cells with this morphology within skin infiltrates is insufficient evidence for the diagnosis of primary T-cell dyscrasia.

Diagnosis, Differential↗
PubMed1977

Neurilemoma-like uterine myomas: an ultrastructural reaffirmation of their non-Schwannian nature.

Some uterine leiomyomas demonstrate a curious rhythmic pattern of cellular arrangement, suggesting the appearance of nerve sheath tumors. Leiomyomas of similar appearance are more frequently found in the gastrointestinal tract. Ultrastructural examination of two such tumors from the uterus, one simulating the Antoni type A pattern and the other predominantly of the Antoni type B pattern, showed features of smooth muscle cells to be present in both. There also was a close fine structural resemblance to light microscopically similar tumors of the gastrointestinal tract. This study should dispel the implications that these tumors are of Schwannian origin.

Adult↗