Juxtaglomerular cell tumor of the kidney

The authors describe a juxtaglomerular cell tumor (JGCT) which caused severe hypertension in a 58-year-old man. Light microscopy showed a circumscribed tumor composed of interlacing cords and occasional nodules of relatively uniform cells with no mitotic activity. Rhomboid crystals characteristic of "prerenin" were present within the cytoplasm of tumor cells, and there was a close relationship between the tumor and unmyelinated nerve axons. Intracytoplasmic renin was demonstrated by immunofluorescence, and tumor granules were shown to contain zinc by electron-beam microanalysis. Review of 14 prior cases, with additional follow-up of 9, showed that no patient had developed recurrence, metastasis, or another tumor. Four patients, however, are hypertensive but probably because of secondary tumor effects rather than recurrent hyperreninism. The distinction of JGCT from hemangiopericytoma with renal involvement is important because of the high mortality associated with the latter. The authors conclude that JGCT is benign, but patients with JGCT may remain hypertensive postnephrectomy because of hypertensive angiopathy.     

Identification of phase I metabolites of 3-methylindole produced by pig liver microsomes.

A study was conducted to investigate qualitative and quantitative aspects of the phase I metabolism of 3-methylindole (3MI) by porcine liver microsomes. Microsomal suspensions were prepared from the liver of 30 intact (uncastrated) male pigs. Metabolites produced in microsomal incubations were identified and quantitated with HPLC-UV, HPLC-fluorescence, and UV-spectral analysis; liquid chromatography-mass spectrometry (LC-MS) and NMR were used for the identification of a metabolite for which a reference compound was not available. The results showed that seven major metabolites of 3MI are produced by porcine microsomes, three of which had already been identified in pigs (3-OH-3-methyloxindole, 5-OH-3-methylindole, and 6-OH-3-methylindole). The other four major 3MI metabolites identified were 3-OH-3-methylindolenine, 3-methyloxindole, indole-3-carbinol, and 2-aminoacetophenone. On average, the metabolite that was produced in larger amounts was 3-OH-3-methylindolenine (45.1%), followed by the two oxindoles 3-methyloxindole (27.9%) and 3-OH-3-methyloxindole (18.5%). Average percentage of production of 6-OH-3-methylindole was 4.9%, whereas indole-3-carbinol accounted for 2.7% of all metabolites produced; 2-amino-acetophenone and 5-OH-3-methylindole were the metabolites produced in lesser amounts (0.5 and 0.3%, respectively). Large interindividual differences in the rate of production of all metabolites were observed. This variation could be attributed to differences in the activity and/or level of expression of phase I biotransformation enzymes and this issue should be further investigated.     

Suicide by fire in Scotland: 1980-1990

Suicide by fire is relatively rare in the Western world, accounting for approximately 1% of completed suicides by all methods. This survey identified suicidal deaths among fatalities known to the Scottish Fire Brigades as having died in a fire incident during 1980 to 1990. It is accepted that this is just one possible definition of what constitutes a suicide by fire. Forty cases were identified as suicides from the circumstances of the death as narrated in the police and Fire Brigade reports of the incident. Autopsy and toxicological reports were examined for all cases and the characteristics of the victim and the incident are described. Most cases occurred in the home of the victim and three-quarters of the victims were pronounced dead at the scene or when first seen by a doctor. Smoke inhalation was the most frequently certified cause of death. Alcohol was present in less than half the cases and toxicological analysis for drugs was performed in the minority of cases. One-quarter of victims were reported to have made at least one suicide attempt previously. A range of apparently precipitating factors was observed: the number of cases which appeared to be impulsive responses to life events suggests that prevention is difficult.     

Response properties of long-latency event-related potentials evoked during NREM sleep

The experiments reported here sought to investigate whether the K-complex evoked during sleep is comprised of activity from two separate physiological systems with different response properties. To that end, the parameters of stimulation in a two tone auditory 'odd-ball' task were varied systematically as stimuli were presented to subjects during NREM sleep. During experiment 1, the frequency (pitch) of the odd-ball stimulus varied systematically while intensity (loudness) was matched between tones. During experiment 2, pitch was matched between tones while the loudness of the odd-ball stimulus was varied. The long-latency event-related potentials (ERPs) N2 and P3 could be dissociated from the K-complex (N3 and P4) in response to these parametric manipulations. Information processing occurs during sleep, and is reflected in ERPs with a morphology largely analogous to those observed under similar conditions while subjects are awake. The second (K-complex) system is sleep specific. A model was constructed to explain the activity of these two hypothesized systems. As predicted by the model, K-complex latency was longer in Stage 2 when N2 and P3 were also active, than in Stage 4 where N2-P3 activity was lessened. These results support the two-system hypothesis; electrical brain activity evoked during sleep should not be considered a unitary sleep-specific response. Furthermore, the data indicate that the K-complex is sensitive to the physical characteristics of stimuli, that the sleeping brain processes information to a high degree, and that the 'endogenous' components of the ERP observed in awake humans reflect more automatic processes than previously suspected.     

Enhancement of 3H-diazepam binding by SQ 65,396: a novel anti-anxiety agent.

SQ 65,396, a clinically active anti-anxiety agent, enhanced the binding of 3H-diazepam at 1.5 nM. This effect was due to an increase in the affinity for the ligand, without a change in the number of 3H-diazepam binding sites. This action of SQ 65,396 may mediate its anti-anxiety effects by affecting the action of an endogenous modulator of the "benzodiazepine receptor." Several other substances and treatments increase the affinity of 3H-diazepam for its receptors by mechanisms which may be related to the effect produced by SQ 65,396.