Mitochondrial content of choroid plexus epithelium

 The objective of the present study was to examine the apparent work capacity of one of the two separate membrane systems (the blood-cerebrospinal fluid barrier) that isolate the mammalian brain extracellular fluid (and cerebrospinal fluid, CSF) from plasma. Digitized analyses of electron-microscopic images provided estimates of mitochondrial volumes, which were expressed as a percentage of the cell cytoplasm. We recorded a high mitochondrial content of 12–15% in the cuboidal epithelium of primate choroid plexus, which was consistent in vervet, rhesus, and squirrel monkeys, as well as in baboons. Similarly high mitochondrial contents were observed in the rabbit, rat, and mouse choroid plexus. It has been postulated that the high mitochondrial content of brain endothelium is associated with maintaining the ionic gradients within the central nervous system. We observed that the mitochondrial content of the choroid plexus (where CSF is produced) was slightly higher than in (prior measurements of) the blood-brain barrier (BBB). In addition, surface areas at the apical borders of the choroid plexus epithelia (where the Na⁺K⁺ATPase activity has been localized) were increased 7- to 13-fold over the basal borders, in the primate species examined. The observation of high mitochondrial volumes in choroid plexus cells is consistent with the suggestion that increased mitochondrial densities seen in choroidal epithelia and BBB capillaries provide a metabolic work capability for both secretory activities and maintaining ionic gradients across blood-CSF barriers. Received: 25 February 1997 / Accepted: 2 May 1997     

Life expectancy in England: variations and trends by gender, health authority, and level of deprivation.

STUDY OBJECTIVES: To investigate variations and trends in life expectancy in English district health authorities in relation to gender and Jarman deprivation level. DESIGN: Mortality data for English health authorities from 1984-94, compiled by the Office for National Statistics, were assessed conventionally and using life table techniques. SETTING: District health authorities in England. MAIN OUTCOME MEASURES: Life expectancies in the 105 DHAs in relation to rank, to gender, and to deprivation category based on the census based Jarman score. CONCLUSIONS: Differences in life expectancy had widened over the decade and prosperous areas with greatest longevity had seen the largest gains. In most deprived areas improvements in life expectancy were negligible. The greatest gender differences in life expectancy were also seen in deprived areas.     

Reductive fragmentation of 2-nitroimidazoles: amines and aldehydes

Glyoxal has been identified as a product in the fragmentation of reduced 2-nitroimidazole radiosensitizers. Quantitative analysis of glyoxal as its bis (2,4-dinitrophenylhydrazone) derivative shows that it is formed in good yield (9-23%) in a variety of 2-nitroimidazoles. In addition to glyoxal a second as-yet-unidentified carbonyl compound, and a series of amines are formed when reduced 2-nitromidazoles fragment in the presence of water. One of the amines derived from misonidazole is identified as 1-amino-3-methoxypropan-2-ol, the product of extensive ring cleavage. Radiation chemical reduction of the 2-nitromidazoles proceeds with the consumption of 3 electrons for each molecule reduced. This could imply that a radical disproportionation or dimerization step is involved in the reductive degradation of 2-nitroimidazoles.     

Evaluation of the use of enzymes for functional restitution after spinal cord severance in the rat

In an attempt to duplicate the excellent recovery rates reported by Russian workers using various enzymes to promote spinal cord regeneration, 102 young female rats with appropriate controls were spinally transected at the T5 level; 32 were given hyaluronidase for 15 days followed by trypsin for 75 days; 35 received trypsin only for 15 days; and 35 were injected with Lidase for 15 days after surgery. Controls received vehicle only. All controls remained paraplegic, as did those treated with Lidase (except for weak placing reactions appearing at 5 months). Rats given trypsin only exhibited stronger placing reactions at 2 months, and slight postural improvement by 3 months; none ever improved beyond that point. The hyaluronidase-trypsin rats, however, showed strong placing reactions at 2 months and dramatic postural improvement by 3 months, weight being taken on knees and thighs. In 12 of these 31 rats, weight was taken on the hind legs accompanied by uncoordinated leg movements on one side or the other. This progress disappeared at 3.5 months, and the animals reverted to control condition. Repetition of this experiment with prolonged enzyme administration did not produce the same improvement.     

The effects of orbitofrontal lesions on the aggressive behavior of vervet monkeys (Cercopithecus aethiops sabaeus).

This study examined the role of the orbitofrontal cortex in the integration and expression of aggressive behavior in the vervet monkey (Cercopithecus aethiops sabaeus). Operated and unoperated controls were observed in two settings: In one they were confronted by a human observer and in the other they were members of a social group of conspecifics. Nine animals (four males and five females) underwent orbitofrontal lesions. Operated males and females threatened a human observer more postoperatively than preoperatively, but exhibited no change in the rate of aggressive behavior expressed toward conspecifics. However, operated monkeys were less effective in their aggressive encounters with conspecifics. Operated males lost a greater proportion of dyadic encounters; operated females participated less successfully in coalition-mediated aggression. The postoperative changes exhibited by vervets differed from those reported in rhesus monkeys (Macaca mulatta), which suggests that there may be considerable interspecific variability among Old World monkeys in the effects of orbital frontal lesions on aggressive behavior.