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Biomedical subjects

P Dunn

Publications and source records attributed to P Dunn.

At least 109 records · Page 6Linked to original sources
PubMed1985

A device for interstitial therapy of low pelvic tumours--the Hammersmith perineal hedgehog.

The freehand production of accurate volume or multiplane implants for interstitial therapy is difficult. The size of tumour that may be treated in this fashion is therefore limited. A solution to this problem is to use a perspex template to guide the implant and maintain its configuration during treatment. We describe our experience using such a template (the Syed-Neblett template) in treating pelvic tumours. The device has been adapted for use with the iridium wire available in the UK. Two new templates have been designed which are more versatile for treating tumours in this area. Ten patients have been treated and with appropriate analgesia, antibiotic cover and nursing care the implant was well tolerated.

Adult↗
PubMed1982

Enzyme histochemical characteristics of spontaneous and induced hepatocellular neoplasms in mice.

Hepatocellular neoplasms are known to differ in enzyme activity from the surrounding non-neoplastic liver. We have compared histochemically the enzyme activity of spontaneous hepatocellular tumors in mice with tumors induced by diethylnitrosamine and dieldrin. Some neoplasms had increased activity, others had decreased enzyme activity, yet other had the same activity as the surrounding liver. Alkaline phosphatase, glucose-6-phosphatase, succinic dehydrogenase and adenosine triphosphatase, as well as glycogen levels were studied. Carcinomas differed from adenomas in having elevated enzyme activity significantly more often than adenomas. However, the carcinomas showed elevated glycogen levels less frequently than adenomas. Histochemically, pulmonary metastases resembled the primary hepatocellular carcinomas from which they were derived. Tumors of dieldrin animals were notable in having increased activity of all the enzymes which we studied more frequently than tumors of diethylnitrosamine animals or of controls. Differences in enzyme activity between the three mouse strains were slight.

Adenosine Triphosphatases↗
PubMed1982

Reduction of teenage pregnancy as a rationale for sex education: a position paper.

There is little doubt that the present level of interest in initiating sex education programs in the schools stems from the effort to reduce the teenage pregnancy rate. While one can hardly challenge the respectability of the goal to reduce teenage pregnancy, the writers take the view that the focus on reducing teenage pregnancy may be counter-productive to the establishment of effective sex education programs in school for the following reasons. 1. It promotes a narrow and incorrect understanding of human sexuality and sex education. 2. It creates misunderstanding of what constitutes a comprehensive sex education program. 3. Because the focus is on the junior/senior high youngster the assumption is left that sexuality occurs only between grades six and twelve. 4. It focuses primarily on the female and provides little education for the male. 5. It implies that the majority of teenagers want sex and not babies. 6. It implies that advocating sexual restraint is moralizing (and moralizing is bad) but teaching students that they should use contraceptives to avoid pregnancy is not moralizing. 7. The contraception approach presents human sexuality as a negative behavior because it conveys the impression that sex will get you into trouble if you do not know what to do.

Adolescent↗
PubMed1980

Ultrastructure of spontaneous neoplasms induced by diethylnitrosamine and dieldrin in the C3H mouse.

The spontaneous hepatocellular neoplasms of C3H (MTV-ve) male mice were compared with the hepatic tumors induced in these animals by diethylnitrosamine (DEN) and dieldrin. No morphologic differences could be detected by light or electron microscopy between the spontaneous and induced lesions. However, the animals given diethylnitrosamine or dieldrin developed the lesions earlier, in greater numbers and of larger size. The earliest change was the development of foci composed of clear cells. Later nodules appeared which were composed of clear or basophilic cells. These lesions were followed by and presumably progressed to nodules of trabecular hepatocellular carcinomas. It is postulated that in this series, the first morphological step in the neoplastic transformation is the appearance of unusually clear hepatocytes. Ultrastructurally, the clear cells had increased glycogen and lipid droplets and a decrease in smooth endoplasmic reticulum. The basophilic cells seen later resembled the clear cells except for having a greatly increased rough endoplasmic reticulum. Trabecular hepatocellular carcinomas differed from benign nodules in the greater secretory activity of the rough endoplasmic reticulum, in the development of basement membranes at the vascular pole and of microvilli along the lateral cell membranes. The stepwise progression of normal hepatocytes to hepatocellular carcinoma is discussed on the basis of these sequential light microscopic and ultrastructural observations.

Aging↗
PubMed1979

Enhancement of the thermal response of animal tumors by Corynebacterium parvum.

The effect of Corynecbacterium parvum treatment on the thermal response of animal tumors was studied. Tumors were methylcholanthrene-induced (FSa-II) and spontaneous (FSa-I) fibrosarcomas in C3Hf/Sed mice. C. parvum was given i.v. and was followed by local hyperthermia at 43.5 degrees 3 days later. Cell survival determined by lung colony assays showed that preadministration of C. parvum insignificantly enhanced the thermal response of both tumors. Studies of delay of tumor growth for FSa-II demonstrated that the enhancement ratio decreased with increasing time of treatment and reached a minimum of approximately equal to 1.7. The enhancement ratio for the time at hyperthermia which achieved tumor control in one-half of the treated tumors was 1.7. Together with our previous results on normal tissue responses, the therapeutic gain factor for obtaining 50% tumor control was found to be 1.1 (1.7/1.55) for the weekly immunogenic FSa-II tumor, while it was 2.3 for moderately immunogenic FSa-I as reported previously.

Animals↗
PubMed1978

Composition of and cholesterol in Araucana and commercial eggs.

Araucana eggs from six sources and commercial-type white eggs of two major supermarket brands and from the University of California flock were collected and analyzed for cholesterol content of the yolk. The yolks of Araucana eggs were significantly higher in cholesterol than those of commercial white eggs.

Cholesterol↗
PubMed1978

Enhancement by Corynebacterium parvum of the normal and tumor tissue response to hyperthermia.

The effect of Corynebacterium parvum treatment on the response of tumor and normal tissue to hyperthermia (43.5 degrees) was studied. Animals were C3Hf/Sed mice from our defined flora mouse colony. The time at hyperthermia that achieved control of one-half of methylcholanthrene-induced fibrosarcomas and the foot reaction were examined after treatment. C. parvum, if given 3 to 32 days before hyperthermia, enhanced the reaction to local hyperthermia of normal tissue. No enhancement was observed if C. parvum was given after hyperthermia. This enhancement was more dramatic for tumor response resulting in a therapeutic gain factor of congruent to 2.3 (3.7/1.6). Comparative studies on combined Corynebacterium and radiation failed to demonstrate the enhancement to normal tissue.

Animals↗
PubMed1975

Abnormal pancreatic alpha-cell function in first-degree relatives of known diabetics.

A standard intravenous glucose tolerance test utilizing a 25g glucose load was administered to 15 first-degree relatives of known diabetics and 19 normal control subjects with no known diabetic relatives. Despite normal glucose tolerance, 5 of the first-degree relatives had a significantly lower release of first-phase insulin (p 0.05). In contrast to 8 normal subjects and the remaining 10 first-degree relatives the secretion of glucagon by the 5 first degree relatives with abnormally low insulin release was not suppressed by induced hyperglycaemia. These findings provide evidence of abnormal alpha-cell function in a very early stage of genetic diabetes.

Adult↗