Polychlorinated dibenzofurans--potent inducers of rat hepatic drug-metabolizing enzymes

The effects of polychlorinated dibenzofurans (PCDFs), trace toxic contaminants of commercial polychlorinated biphenyl preparations (PCBs), on the induction of hepatic drug-metabolizing enzymes were studied in the rat. PCDFs were about a thousand times more potent than PCBs (Kanechlor-500) as inducers of cytochrome P-450. Rats given 10 microgram/kg of PCDFs intraperitoneally for 3 days showed significantly increased hepatic cytochrome P-450 levels. At the highest dose tested, 1000 microgram/kg, a two-fold increase of cytochrome P-450 and a three-fold increase of p-nitroanisole demethylase activity were observed. PCDFs and 3-methylcholanthrene had quite similar effects on microsomal drug-metabolizing enzymes. Both drugs increased p-nitroanisole demethylase activity strikingly and aniline hydroxylase activity moderately, but produced little change in aminopyrine demethylase activity. alpha-Naphthoflavone, which is known to be a specific inhibitor of aryl hydrocarbon hydroxylase induced by polycyclic aromatic hydrocarbons, inhibited at low concentrations p-nitroanisole demethylase activity of rats previously treated with both drugs. Further, both drugs increased the 455 nm to 430 nm peak ratios of ethyl isocyanide difference spectra. Following three daily doses of PCDFs (100 microgram/kg), cytochrome P-450 level and p-nitroanisole demethylase activity remained elevated for over 15 days, with a decrease to control levels after 30 days. Such indicates the slow excretion of PCDFs.

Oxidative and phosphorylative activities of the gastric mucosa of animals and humans in relation to the mechanism of stress ulcer

In order to elucidate the mechanism of stress ulceration, which is mainly involved with the corpus mucosa of the stomach, the aerobic energy metabolism of the corpus mucosa of rats, rabbits and humans was investigated and compared with those of the antral mucosa as well as other organs such as heart, kidney and liver. The results showed that the activities of respiration and oxidative phosphorylation and the concentration of the respiratory chain components were far greater in the corpus mucosa than in the antral mucosa, the activities in the former being almost equal to that of the highly aerobic tissue, kidney cortex. Furthermore, the endogenous respiratory rate (in the absence of added substrate) was also much higher in the corpus mucosa than in the antral mucosa, indicating that oxygen demand at resting state (during the period of H+ secretion) is also higher in the corpus mucosa. We conclude that in the corpus mucosa of the stomach the aerobic energy metabolism is predominant. It is suggested that circulatory insufficiency may easily result in cell damage mainly of the corpus mucosa due to energy deficit.

Simultaneous measurement of mitochondrial and microsomal cytochrome levels in human liver biopsy

The mitochondrial and microsomal cytochromes in patients' livers obtained from needle biopsies have been analyzed using a sensitive spectrophotometric method. To determine simultaneously the concentration of these cytochromes from hemoglobin-contaminated liver, difference spectra of liver homogenates were taken at the temperature of liquid nitrogen before and after photolysis of carbon monoxide molecules from various hemoprotein-CO complexes. This method utilizes a characteristic property of hemoprotein-CO complexes, in which the reassociation of CO molecules with photolyzed hemoglobin, cytochrome P-450 and cytochrome alpha3 is temperature-dependent. The results in 69 cases with a variety of liver diseases have revealed that the concentrations of cytochromes alphaalpha3, P-450 and beta5 showed a huge variation in the injured livers as compared with those in the normal controls. The significance of the measurement of these cytochrome concentrations and their ratios is discussed.

Studies on mitochondrial structure and function in Physarum polycephalum. V. Behaviour of mitochondrial nucleoids throughout mitochondrial division cycle

The fine structure of mitochondria and mitochondrial nucleoids in exponentially growing Physarum polycephalum was studied at various periods throughout the mitochondrial division cycle by light and electron microscopy. The mitochondrial nucleoid elongates lingitudinally while the mitochondrion increases in size. When the nucleoid reaches a length of approximately 1.5 mum the mitochondrial membrane invaginates at the center of the mitochondrion and separates the mitochondrial contents. However, the nucleoid does not divide even when the mitochondrial sections are connected by a very narrow bridge. Just before division of the mitochondrion, the nucleoid divides by constriction of the limiting membrane of the dividing mitochondrion. After division, one end of the nucleoid appears to be associated with the inner mitochondrial membrane. The nucleoid then again becomes situated in the center of the mitochondrion before repeating these same processes.

Gastrointestinal bleeding following head injury: a clinical study of 433 cases

The incidence of gastrointestinal bleeding was studied in 433 patients with head injury. This complication has a strong correlation to the severity of the injury. Other factors such as shock, arterial pO2 and glucocorticoid administration were not related to incidence of gastrointestinal bleeding. Forty per cent of patients developed bleeding within 48 hours and approximately and additional 40% within one week. Only nine patients required more than 1,000 ml of blood, and eight of these died and one requiring emergency abdominal surgery lived.

Downward displacement of the left kidney caused by ectopic ovarian cyst developing in the subphrenic region

A rare case of downward displacement of the left kidney caused by marked development of an ectopic ovarian cyst in the left subphrenic region is presented. Exact diagnosis could not be made preoperatively but a satisfactory result was obtained by removal of the cyst. Histological diagnosis of the tumor was serous cystadenoma arising from the left ovary.

Glioblastoma with extracranial metastasis through ventriculopleural shunt. Case report

✓ Extracranial metastasis of an intracranial glioblastoma through a ventriculopleural shunt to the right thorax is reported in a 22-year-old man following a ventriculopleural shunt and telecobalt therapy. Autopsy 8 months after the shunt showed cerebral tumor involving the ventricular system, and irregularly thickened pleura in the right thorax. The primary intracranial tumor and the tumor located extracranially showed the same morphological appearance of glioblastoma.