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Biomedical subjects

C Thompson

Publications and source records attributed to C Thompson.

At least 325 records · Page 18Linked to original sources
PubMed1988

Massive renal and retroperitoneal hemorrhage in a case of acquired renal cystic disease with atypical epithelial cell proliferation.

We present a case of acquired renal cystic disease in a patient with end-stage renal disease (ESRD) secondary to systemic lupus erythematosus who was dialysis dependent for 5 years. Renal hemorrhage and neoplastic transformation of the cyst epithelium are the two major complications of acquired renal cystic disease, and were present in this patient. The full clinical significance of the acquired renal cystic lesion is still unclear, although the possibility of renal tumors and massive renal and retroperitoneal hemorrhage should be considered in the long-term dialysis population.

Adult↗
PubMed1988

Multiple mechanisms for transcriptional regulation of the myc gene family in small-cell lung cancer.

The molecular mechanisms reported to regulate the expression of myc family genes are multiple and complex and include gene amplification, transcriptional activation, transcriptional attenuation, and mRNA stability. We have investigated which of these mechanisms are responsible for the extreme variation in myc gene family mRNA levels observed in human small-cell lung cancer cell lines. In addition to gene amplification, a block to nascent mRNA chain elongation, causing attenuation of transcription, is an important regulatory mechanism controlling the steady-state levels of c-myc and L-myc mRNA. The loss of transcriptional attenuation is correlated with overexpression of these two genes in cell lines which do not show gene amplification. Expression of c-myc mRNA appears to be dependent on promoter activity and attenuator function. In contrast, regulation of expression of the N-myc gene does not involve transcriptional attenuation; steady-state mRNA levels are correlated with promoter activity as well as gene amplification. We conclude that transcriptional regulation of each member of the myc gene family is accomplished by a different assortment of complex mechanisms, including gene copy number, promoter activation, and transcriptional attenuation. Interference at multiple points in this complex regulatory process appears to be an important mechanism by which small-cell lung cancer and other human tumors evade growth control.

Carcinoma, Small Cell↗
PubMed1988

A comparison of melatonin secretion in depressed patients and normal subjects.

Depressed patients were carefully matched in pairs with normal subjects for the variables which are known to influence the secretion of melatonin in humans. In contrast to the previous literature, nocturnal melatonin secretion was not lower in the depressed group than in the normal group, and there was no difference in the timing of secretion; indeed, the trend was for greater melatonin secretion in the depressed group. The results are discussed in relation to previous studies, none of which has been so carefully controlled for the relevant variables.

Adult↗
PubMed1988

Effects of thallium poisoning on intellectual function.

A student of chemistry was treated for thallium poisoning. Seven months after his ingestion of thallium, intelligence tests were performed on the patient and his non-identical twin brother, who was of similar educational background. These indicated severe deterioration in intellectual function of the patient, particularly in memory and performance abilities. Tests 13 months after ingestion showed little general improvement.

Adult↗
PubMed1988

Psychosis associated with HIV infection.

Five cases of psychiatric illness, presenting as functional psychosis, occurring in male homosexuals with human immunodeficiency virus (HIV) infection are described and compared with similar cases in the literature. The association between psychosis and infection with HIV is discussed with particular emphasis on the significance of functional versus organic presentation.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Clinical experience with preferential looking acuity tests in infants and young children.

Early preferential looking methods for the assessment of infant visual acuity relied upon formal psychophysical procedures that were lengthy and only easily applicable to laboratory studies. Two clinically appropriate techniques evaluated in this study both maintain a forced-choice testing protocol and are administered by a single examiner. One method employs a specially constructed optical projection system to present gratings in a dark-room. The second method relies upon a commercially available acuity card test, used with good room lighting. Paediatric clinical patients and normal infants and young children were examined using both techniques. Findings demonstrate that suitably adapted preferential looking methods can provide rapid and valid estimates of visual acuity in infants and young children. The tests appear sufficiently robust to be appropriate for routine clinical use.

Age Factors↗
PubMed1987

alpha-Naphthoflavone metabolized by 2,3,7,8-tetrachlorodibenzo(p)dioxin-induced rat liver microsomes: a potent clastogen in Chinese hamster ovary cells.

alpha-Naphthoflavone (ANF) is a widely used inhibitor of P-450-mediated metabolism. Previously, we have demonstrated that in vitro addition of ANF to human lymphocytes produced significantly greater numbers of sister chromatid exchanges (SCEs) in samples from smokers compared to nonsmokers. In order to study the mechanism of this differential induction, we investigated the clastogenic activity of ANF as a consequence of metabolism by induced and uninduced rat liver microsomes. Exponentially growing Chinese hamster ovary cells were treated with ANF for 2 h in the presence or absence of microsomes, followed by incubation for 12 (chromosome aberrations) or 24 h (SCEs). ANF induced concentration (4 to 40 microM)-dependent increases in SCEs and chromosome aberrations when coincubated with 2,3,7,8-tetrachlorodibenzo(p)dioxin-induced microsomes. At the lower concentrations of ANF, chromatid damage was most predominant, whereas at the higher concentrations, a high percentage of cells was killed. The surviving cells exhibited shattered chromosomes and multiple damage in the form of chromatid exchanges and breaks. ANF was not clastogenic nor did it induce SCEs in Chinese hamster ovary cells when incubated with microsomes from control rats or phenobarbital-treated rats. Moreover, NADPH was required for the clastogenic actions of ANF in the presence of 2,3,7,8-tetrachlorodibenzo(p)dioxin-induced microsomes. Analysis of the ANF metabolites by high-pressure liquid chromatography revealed that 2,3,7,8-tetrachlorodibenzo(p)dioxin-induced microsomes metabolized ANF to a much greater extent than control or phenobarbital-induced microsomes. Our results suggest that the clastogenic activity of ANF in Chinese hamster ovary cells is mediated by the cytochrome P-450 monooxygenase system.

Animals↗
PubMed1987

Engineering herbicide resistance in plants by expression of a detoxifying enzyme.

Phosphinothricin (PPT) is a potent inhibitor of glutamine synthetase in plants and is used as a non-selective herbicide. The bar gene which confers resistance in Streptomyces hygroscopicus to bialaphos, a tripeptide containing PPT, encodes a phosphinothricin acetyltransferase (PAT) (see accompanying paper). The bar gene was placed under control of the 35S promoter of the cauliflower mosaic virus and transferred to plant cells using Agrobacterium-mediated transformation. PAT was used as a selectable marker in protoplast co-cultivation. The chimeric bar gene was expressed in tobacco, potato and tomato plants. Transgenic plants showed complete resistance towards high doses of the commercial formulations of phosphinothricin and bialaphos. These data present a successful approach to obtain herbicide-resistant plants by detoxification of the herbicide.

Journal Article↗