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Biomedical subjects

M Cartwright

Publications and source records attributed to M Cartwright.

10 recordsLinked to original sources
PubMed1992

The human nerve growth factor gene: structure of the promoter region and expression in L929 fibroblasts.

We previously studied the transcriptional mechanisms involved in expression of the murine nerve growth factor (NGF) gene. To investigate the regulation of transcription of the human NGF gene, the promoter region was cloned. The nucleotide sequences of the human and mouse genes are greater than 90% similar near their promoters. The cloned human promoter was transcriptionally active in mouse L929 fibroblasts. 5' Deletion analyses indicated that the -85 to -45 region stimulates basal transcription 6-fold. This segment is greater than 80% identical in human and mouse genes except for an AP-1 consensus sequence found only in the human gene. A second AP-1 consensus sequence at +34, previously shown to function as a regulatory element in the mouse gene, is identical in both genes. Gel shift analyses of L929 cell extracts revealed binding of protein to oligonucleotide probes spanning each of the two AP-1 consensus sequences of the human gene. The gel shift patterns differed, suggesting interaction of different proteins with the two probes. Our results demonstrate that the human NGF gene promoter is transcriptionally active in mouse fibroblasts, and implicate an upstream region in basal transcription.

Animals↗
PubMed1989

Comparison of renal biopsy techniques in dogs.

To evaluate adequacy of biopsy specimens obtained and safety to the patient, the standard keyhole biopsy technique (using digital immobilization of the right kidney and placement of the biopsy needle up to the capsule before obtaining a tissue sample) was compared with 9 technical modifications. Adequacy was judged by the number of intact glomeruli observed in the specimen. Detection of transected blood vessels and renal pelvis was presumed to have predictive value for postbiopsy complications of hemorrhage and hydronephrosis. Needle biopsy specimens were also obtained from left and right kidneys by use of laparoscopic visualization and were compared with those obtained by use of the standard keyhole technique. Although the standard keyhole technique yielded the highest percentage of adequate biopsy specimens, there was no statistical difference between specimens obtained by this technique and those obtained by the modified technique or by laparoscope-guided biopsy. Also, significant difference in percentage of biopsy specimens with renal pelvis was not found between specimens obtained by the standard and modified techniques. For each technique, the biopsy core length was measured and the mean value was calculated. In this study, core length did not correlate with adequacy of the biopsy specimen.

Animals↗
PubMed1986

A model for the control of testosterone secretion.

We produce here a model to explain the control of testosterone secretion. In this model the hypothalamic secretion of the hormone LHRH (luteinizing hormone releasing hormone) is controlled by a combination of local testosterone concentration and of the local concentration of the pituitary hormone LH (luteinizing hormone). Since LHRH stimulates the release of LH, and LH in turn stimulates the release of testosterone, the three hormones constitute a three-component "feedback" network. We show how this model is able to account for the pulsatility of the release of these three hormones. Furthermore, the model is consistent with results obtained from a wide range of experimental manipulations of the system. For example, it accounts for the changes observed in hormone release patterns after castration. In particular, it follows that no "neural clock", or "neural pulse-generator", is required to force the system into pulsatile behaviour.

Gonadotropin-Releasing Hormone↗
PubMed1985

Psittacine inclusion body hepatitis in an aviary.

Psittacine inclusion body hepatitis (also known as Pacheco's parrot disease) was believed to be responsible for fatal necrotizing hepatitis and splenitis in a variety of psittacine birds from a private aviary. Splenic cells and degenerative hepatocytes around the outer zone of necrotic areas had margination of nuclear material and large intranuclear inclusion bodies. Clinical signs consisted of weakness, anorexia, vomiting, loose feces, and slight ruffling of feathers. The source of the infection was undetermined, but could have been associated with 3 Patagonian conures within the aviary. Patagonian conures are well-recognized as clinically normal carriers. The outbreak was limited by strict quarantine and disinfection of the aviary for 14 days.

Animals↗