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Biomedical subjects

C Harper

Publications and source records attributed to C Harper.

At least 109 records · Page 6Linked to original sources
PubMed1982

Cerebral dissecting aneurysm and intimal fibroelastic thickening of cerebral arteries. Case report.

A 19-year-old white man developed aphasia and right hemiplegia after several falls while waterskiing. Cerebral angiography displayed a ripple appearance and a "string of beads" sign along the left middle cerebral artery, with occlusion or stenosis of most of its branches. The patient died after 6 days, of transtentorial herniation due to massive left cerebral infarction. At necropsy, the infarct was found to be due to a subintimal dissecting aneurysm of the left middle cerebral artery. Multifocal areas of intimal fibroelastic thickening (IFT) were found not only at the site of dissection, but also in the other cerebral arteries, most prominent at the bifurcations of the vessels. A systematic study of cerebral arteries performed in six control cases revealed that IFT was present in a similar distribution to that seen in the patient described. However, the degree of IFT in this patient was greater than in the controls. Some individuals with excessive IFT may be more susceptible to cerebral dissecting aneurysm under a variety of stresses, especially trauma.

Adult↗
PubMed1981

A comparison of Australian caucasian and aboriginal brain weights.

The weights of normal brains obtained at autopsy from Royal Perth Hospital and the Perth City Coroner's Department during the last decade were reviewed. The analysis involved 728 Caucasian and 63 Aboriginal brains. The ages ranged from 21 to 90 years, but the Aboriginal group were generally younger than the Caucasian. All brains were examined in detail by the Neuropathology Department, Royal Perth Hospital. Brains with any significant macroscopic or microscopic abnormality were excluded from the analysis. Statistical comparisons between the brain weights of the Caucasians and Aboriginal subpopulations show that Aboriginals had smaller brains than Caucasians. Even after correcting for body height, Caucasian brain weights were significantly heavier than Aboriginal brain weights. Results also showed that men had significantly higher mean brain weights than women of the same age. There was a tendency for the mean brain weight of both men and women to decrease in later life, particularly in the eighth and ninth decades. Ho et al. (1980) showed in their analysis of 1261 brains in the USA, that brain weight decreases from white males to black males to white females to black females. The tendency in both this and the present investigation for the non-Caucasians to have smaller brains than the Caucasians warrants further study.

Adult↗
PubMed1979

Wernicke's encephalopathy: a more common disease than realised. A neuropathological study of 51 cases.

During a four year peirod, 51 cases of Wernicke's encephalopathy were diagnosed at necropsy, an incidence of 1.7% of all necropsies performed at the Royal Perth Hospital and by the Perth City coroner. Only seven had been diagnosed during life. Many of the patients died suddenly and unexpectedly, apparently as a result of haemorrhagic brainstem lesions, typical of acute Wernicke's encephalopathy, since no other cause of death was found. There was a high incidence of epilepsy and four patients were hypothermic. The diagnosis of Wernicke's encephalopathy may be missed at necropsy unless the brain is examined histologically. Cerebral atrophy and ventricular dilatation were common findings. This is a more common disease than is generally recognised, one which can be readily treated and, more importantly, prevented by adequate nutrition.

Adult↗
PubMed1979

Superior sensitivity of conjugates of horseradish peroxidase with wheat germ agglutinin for studies of retrograde axonal transport.

We have compared the retrograde axonal transport of horseradish peroxidase (HRP), to the retrograde transport of HRP conjugated with wheat germ agglutinin (WGA). Morphometric studies have shown that WGA-HRP conjugates were 40 times more sensitive than free HRP, in the tracing of retrograde connections from the rat submandibular gland to the superior cervical ganglion. Also, WGA-HRP was more sensitive than free HRP in the tracing of retrograde connections from the rat tongue to the hypoglossal nucleus. Our findings with WGA-HRP are consistent with the observations by Schwab et al. who reported (-125I) WGA is a highly sensitive retrograde tracer (Brain Research 152:145, 1978 (22)).

Animals↗
PubMed1977

Comparison of aerosolized atropine sulfate and SCH 1000 on exercise-induced bronchospasm in children.

The new anticholinergic compound Sch 1000 (ipratropium bromide) has been reported to be an effective bronchodilator without significant atropine-like side effects. We evaluated the effectiveness of different doses of nebulized Sch 1000 (40 microgram and 80 microgram) aerosolized atropine sulfate (1 mg) and placebo in the prevention of exercise-induced bronchospasm (EIB) in 20 children with atopic bronchial asthma. A random, crossover double-blind protocol was used. Standard exercise on a cycloergometer was used to induce EIB. Pulmonary function was determined before and after drug administration and exercise. Following no treatment or placebo, exercise resulted in average reductions of 33% to 43% in plethysmographic specific airway conductance (SGaw), of 20% to 25% in forced expiratory volume in 1 sec (FEV1), and of 25% to 32% in maximal midexpiratory flow rate. Exercise following no treatment or placebo resulted in average increases of 23% to 30% in thoracic gas volume (Vtg). Prior to exercise atropine and either dose of Sch 1000 caused significant increases in SGaw (48% to 59%). After pretreatment with Sch 1000 or atropine, exercise caused SGaw to fall to values that were not significantly different from pretreatment medication values, but were significantly higher than values following exercise without pretreatment or after pretreatment with placebo. No significant differences were noted between the effects of atropine and Sch 1000 on EIB. We conclude that at the doses used atropine and Sch 1000 cause equivalent degrees of bronchodilation but neither drug specifically inhibits EIB.

Adolescent↗
PubMed1976

Calcium metabolism during lactation: enhanced effects of thyrocalcitonin.

Lactating rats were compared with nonlactating controls, with regard to the intake and absorption of calcium, serum calcium level, and te protective effect of thyroacalcitonin (TC) against hypercalcemia and hyperphosphatemia. While consuming a commercial diet, intact, nonfasted lactating rats maintained a serum calcium level of approximately 9 mg/100 ml, which was 1 mg/100 ml lower than that of nonlactating controls. The level rose to that of the controls within one day after removal of the litters from the mother. Compared with nonlactating rats, lactating rats had a three-fold higher calcium intake and a six-fold higher rate of net absorption of calcium. After intragastric calcium (10 mg/100 g body wt) the increase in serum calcium was small (1 mg/100 ml) 2 h later in both groups of sham-operated rats but was markedly increased in thyroparathyroidectomized groups, with the lactating rats showing a significantly greater increase than the nonlactating rats. The injection of a small dose of porcine thyrocalcitonin completely counteracted this hypercalcemia in lactating rats, but did not have any effect on nonlactating controls. Protection by the thyroid gland against hyperphosphatemia after intragastric calcium also was significant in both lactating and nonlactating rats. The results show that TC is much more effective in lactating than in nonlactating rats, suggesting that TC may be of particular importance in lactation by restricting elevations of serum calcium and phosphorus levels after eating, thereby aiding in conservation of these ions.

Animals↗
PubMed1975

Effects of vinyl chloride exposures to rats pretreated with phenobarbital.

Male rats were exposed to 10 consecutive days, 6 hr/day, to vinyl chloride vapors at an average concentration of 13,500 ppm. The exposed rats were divided into three groups of eight rats each: one group was pretreated with 3-methylcholanthrene, one group was pretreated with phenobarbital, and the third group received no treatment. Half the animals in each group were sacrificed 18 hr after the last exposure and half were sacrificed 4 days later. In a second experiment, four rats pretreated with phenobarbital were exposed to vinyl chloride vapors at a concentration of 17,300 ppm for 2 days and sacrificed about 9 A.M. on the third day. In both experiments control animals, also treated with phenobarbital or 3-methylcholanthrene, were exposed to air only. At the time of sacrifice, lungs, kidneys, spleen, heart, and a small piece of liver from each animal were preserved for histological examination. The remainder of the liver was processed for assay of microsomal enzyme activity. The following parameters were investigated: growth rate, organ weights, morphological changes, and both benzphetamine-N-demethylase activity and cytochrome P-450 content of microsomes prepared from the livers. In both experiments the only marked difference noted in any group was a decrease in the growth rate of the animals exposed to vinyl chloride and treated with phenobarbital. This decreased growth rate was particularly apparent on the third day of the vinyl chloride exposures. Occasional morphological changes were also seen in the livers of the animals treated with phenobarbital and exposed to vinyl chloride.

Animals↗