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Biomedical subjects

M H Pinnock

Publications and source records attributed to M H Pinnock.

15 recordsLinked to original sources

The serum levels of some trace and bulk elements in cancer patients.

The levels of copper, zinc, calcium, manganese and magnesium have been monitored in the sera of patients suffering from various types of cancer. Only serum copper appeared to be of any diagnostic significance, its levels being above the normal reported range in the breast cancer, leukaemia and Hodgkin's lymphoma patients. In the case of breast cancer, serum copper is progressively elevated according to the stage of the disease. Serum calcium levels were also significantly lower in patients with tumours of the breast, gastrointestinal tract and cervix. The results suggest that serum copper levels could be of prognostic significance in breast cancer patients receiving radiotherapy.

Adolescent↗

The influence of electrostimulation on hexobarbital induced loss of righting reflex in rats.

Electrostimulation (ES) of slow (SF, 10 Hz) or fast (FF, 500 Hz) frequency decreases the sleeping time of rats anaesthetized by administration of acute doses of hexobarbital. When ES is applied via the ears, both SF and FF are equally efficient in reducing the loss of righting reflex (LRR), whereas if ES is applied peripherally via the paws, only FF decreases the acute narcosis time. Applied cranially, either continuous stimulation or administration of intermittent current (5 minutes on and off) were equally effective in reducing narcosis. A decreased period of 30 minutes' continuous stimulation will reduce sleeping time only if administered immediately after LRR. When restrained animals received ES for periods of up to 3 hours prior to administration of the barbiturate, the sleeping time of the stimulated and sham treated animals were not significantly different.

Animals↗

Use of inverted intestinal sacs to assess the effect of gastrointestinal insult on carcinogen absorption.

Rats were subjected to various forms of treatment in the manner likely to induce gastrointestinal insult. These and control animals were sacrificed and, using inverted sacs, the rate of absorption of either dimethylnitrosamine and benzo(a)pyrene determined. The gastrointestinal injury resulting from the differing treatments did not significantly affect the absorption of benzo(a)pyrene, whereas that of dimethylnitrosamine was significantly increased after each incubation time, most notably by alcohol pretreatment. The results demonstrate that intestinal damage increases the absorption of some carcinogens.

Animals↗

The influence of zinc status on the anti-Lewis lung tumour activity of cisplatin and gallium.

Treatment of C57/BL mice with either cisplatin or gallium nitrate inhibited the growth and metastasis of the Lewis lung tumour and these anti-tumour agents also lowered the zinc levels of some tissues. Nutritional zinc deficiency or the deficiency arising from treatment with the chelating agent, penicillamine, also restricted tumour growth. Although the anti-tumour activity of cisplatin was enhanced in zinc-deficient mice, many of these animals died before sacrifice 14 days after tumour inoculation. The results indicate that zinc status could have considerable bearing on the therapeutic index of the mental-containing anti-cancer drugs.

Animals↗

Comparison of concentrations of some trace, bulk, and toxic metals in the hair of normal and dyslexic children.

Hair from dyslexic children, analyzed by flameless atomic absorption spectrometry, showed significantly higher concentrations of magnesium and copper than did hair from control subjects. The hair from dyslexic children also contained significantly higher concentrations of aluminum and cadmium than that from control children; the cadmium concentration exceeded the normal acceptable range. There were no significant differences in the case of lead, calcium, selenium, or mercury. Our results indicate that excessive cadmium burden could be implicated in this form of learning disorder.

Adolescent↗

The effect of isolation stress on some hepatic drug and carcinogen metabolising enzymes in rats.

Rats were subjected to stress by isolation for periods of up to eight days, which produced an elevation in plasma cortisol. In vivo drug metabolism as estimated by the plasma elimination rate of orally-administered antipyrine was not significantly affected by this treatment although there was an apparent decrease in the absorption rate of the drug. In vitro experiments on hepatic microsomal preparations derived from stressed animals indicate that this stress increased in the activity of some enzyme systems concerned with benzo(a)pyrene activation and this correlated with an increased binding of the carcinogen to DNA. The activity of conjugating enzyme which could catalyze the excretion of such carcinogens was not significantly altered. The results indicated that stress could have an important bearing on carcinogenesis by enhancing to a greater extent enzyme systems responsible for activation than those involved in the excretion of polycyclic aromatic hydrocarbons.

Animals↗

Correlation between tumour size, metastatic spread and galactosyl transferase activity in cyclophosphamide-treated mice bearing the Lewis lung carcinoma.

Galactosyl transferase activity was measured in tumour and normal tissues of mice receiving cyclophosphamide treatment for Lewis lung carcinoma. Animals which responded to cyclophosphamide therapy had significantly smaller tumours with fewer metastases than the untreated mice. The level of galactosyl transferase was significantly reduced in the tumours which were inhibited by the cyclophosphamide treatment.

Animals↗

The effect of chronic alcohol intake upon the hepatic microsomal carcinogen-activation system.

Ethanol was administered to mice either by repeated intraperitoneal injection, or orally in the drinking water over an extended period of time. Following intraperitoneal ethanol pre-treatment further groups of mice received an injection of benzo(a)pyrene. Alcohol intake decreased the level of microsomal aryl hydrocarbon hydroxylase which corresponded to the observed decrease in DNA binding of benzo(a)pyrene. In contrast, the number of tumors which developed in the alcohol pre-treated mice exceeded those of the control animals.

Administration, Oral↗

The effect of chronic ethanol intake on the growth and spread of some murine tumors.

The effect of chronic ethanol intake on the growth and spread of some murine tumors has been investigated. The treatment had no effect on the B 16 melanoma but tended to decrease the number of Ehrlich ascites cells. In the case of the Lewis lung carcinoma, administration of ethanol for two weeks tended to lower the number of metastases to the lung without significantly affecting the primary tumor size, whereas more prolonged ethanol intake decreased the weight of the primary tumor in addition to decreasing its dissemination.

Alcoholism↗