The influence of the brain hormone on retention of blood in the mid-gut of the mosquito Aedes aegypti (L.). III. The involvement of the ovaries and ecdysone.

Most female mosquitoes require a blood-meal in order to produce mature o?cytes. An egg development neurosecretory hormone (EDNH), which is produced in the medial neurosecretory cells (m.n.c.) of the brain and stored in the corpus cardiacum, is released into the haemolymph following the ingestion of blood and is essential for the promotion of ovarian development to maturity. It has been shown that a factor from the m.n.c., presumably EDNH, is necessary if the blood-meal is to be retained in the mid-gut until the o?cytes approach maturity. The present paper shows that retention is not a direct result of the action of EDNH, but is dependent on the ovaries and may well involve ecdysone. Removal of the ovaries before a blood-meal leads to early haem-defaecation, but delay can be restored by injection of ecdysterone. Sub-threshold feeders and mosquitoes decapitated immediately after the intake of blood, each of which would be expected to eliminate the blood-meal early, also show a delay in the onset of haem-defaecation when injected with ecdysterone. Further, both in ovariectomized insects and sub-threshold feeders the time of onset of haem-defaecation is associated with the dose of ecdysterone given.     

Clinical and pathological features of six cases of sarcoidosis presenting with renal failure

Six patients with biopsy-proven renal sarcoidosis presented with renal failure of unknown origin; in none was the diagnosis of sarcoidosis initially considered. The serum creatinine concentration at the time of presentation ranged from 265 to 1380 μmol/l (3.0 to 15.6 mg/dl), with a mean of 787 μmol/l (8.9 mg/dl). Although only two patients were hypercalcemic at the time of presentation, the 24-hour urinary excretion of calcium was increased in three of the four patients in whom it was measured, and renal calculi were present in one case. Renal biopsy revealed interstitial nephritis and tubular atrophy in all cases, as well as nephrocalcinosis in three cases and noncaseating granulomas negative for acid-fast bacilli in four cases. In each patient steroid therapy led to a rapid improvement in renal function (mean post-treatment serum creatinine level 274 μmol/l [3.1 mg/dl]). The follow-up period ranged from 8 months to 8 years (mean 3.0 years). In three patients renal function remained stable with low-dose steroid therapy. In two cases recurrent hypercalcemia and deteriorating renal function accompanied steroid withdrawal but resolved with its reinstitution. In one additional case reversible deterioration in renal function accompanied tapering of the steroid dose; however, there was no hypercalcemia.This report emphasizes the importance of considering sarcoidosis in the differential diagnosis of acute renal failure of unknown origin. Long-term follow-up of such patients is essential, as relapse is common.     

Self-titration by cigarette smokers

An 11-week crossover study was carried out in which 12 subjects smoked high-nicotine (1·84 mg standard yield) and low-nicotine (0·6 mg) cigarettes after an initial period of smoking their usual brands with a medium-nicotine yield (mean 1·4 mg). Plasma and urine nicotine concentrations, carboxyhaemoglobin (COHb) concentration, puffing behaviour, 24-hour cigarette consumption, and butt nicotine content were measured. The changes in plasma nicotine and blood COHb concentrations showed that the smokers compensated for about two-thirds of the difference in standard yields when switched to either high- or low-nicotine cigarettes. Thus, compared with the medium-nicotine brand, the intake of nicotine and carbon monoxide was only about 10% higher when subjects smoked the high-nicotine cigarettes, which had a standard yield 30-40% higher than the medium brands; and only about 15% lower when they smoked the low-nicotine cigarettes, which had a standard yield about 50% lower than the medium brands. But nicotine content and urine nicotine concentrations followed a similar pattern. Changes in puffing behaviour and in 24-hour cigarette consumption were only slight.The results show clear evidence of both upward and downward self-titration of nicotine and carbon monoxide (and tar) intakes when smokers change to cigarettes with standard yields that differ over the range studied.     

The protease problem in Neurospora. Variable stability of enzymes in aromatic amino acid metabolism.

A proteolytic activity isolated from Neurospora crassa is shown to be responsible for the variable stability observed in vitro for enzymes involved in aromatic amino acid metabolism. For example, the activity of kynurenine formamidase was insensitive to the action of this protease preparation over a 24-h period of incubation at 25 °C, whereas chorismate synthase, anthranilate synthase, kynureninase, and the five activities of the arom multienzyme system were inactivated during this time. Anthranilate synthase and two of the arom system activities (dehydroquinate synthase and shikimate kinase) were inactivated by the protease preparation within 2 h. Phenylmethanesulfonylfluoride and a specific proteolytic inhibitor from N. crassa prevented inactivation of these enzymes. Spontaneous loss of activity at 25 °C of purified samples of anthranilate synthase, dehydroquinate synthase and shikimate kinase was also prevented by the inhibitors. A method for purifying the inhibitor from N. crassa is described, and its use as a reagent in the analysis of proteolytic action is demonstrated.     

Species density and associations in Caribbean reef corals

The density of scleractinian corals on portions of two reefs in the Grenadine Islands, W. I. has been investigated by direct observation by SCUBA divers. Grid, transect, and random quadrat methods were compared with total samples to determine the precision and accuracy of these techniques. Transect methods were generally satisfactory provided at least 15% of a 400 m² total grid area was included in the sample. The data strongly indicated clumped distributions of all species, although numerical analysis does not indicate the distinct zones reported by other workers. Species associations based on Jaccard's coefficient and cluster analysis showed possible similarities in physical requirements, although few strong associations were found. Data based on 4 m² quadrats generally provided a more reliable estimate of species associations than did data based on 1 m² quadrats. It is suggested that surveys of these reef types may be better based on a number of parallel transects rather than a single transect, and that well-defined zones are more likely to be the exception than the rule.     

Effect of pregnancy on serum alanine concentration in normal and genetically diabetic mice.

Serum alanine concentration was determined in nonpregnant and pregnant normal control Swiss albino (SA) and genetically diabetic KK mice. The serum alanine levels were significantly lower in nonpregnant KK than in nonpregnant SA mice. Fasting elicited hypoglycemia, hypoinsulinemia and hypoalaninemia in both groups of pregnant mice. Oral administration of alanine in nonpregnant and pregnant mice resulted in a significant rise in blood sugar levels within 15 min in both groups. However, the initial blood sugar response to oral alanine was greater in pregnant than in nonpregnant mice. This increase in blood sugar response to exogenous alanine appears to be mediated by glucagon. The data suggest that pregnancy elicits hypoglycemia, hypoinsulinemia and hypoalaninemia in both nondiabetic and diabetic mice.     

The isolation and identification of the female sex pheromones of the red bollworm moth, Diparopsis castanea

The female sex pheromones of the red bollworm moth, Diparopsis castanea, were isolated by solvent extraction of the terminal abdominal segments of the female moth followed by purification of the solvent extract by liquid-solid and gas chromatography. The pheromones were identified by gas chromatographic analysis, micro-ozonolysis, infra-red and mass spectroscopy, and comparison with synthetic material. The major pheromone was 9,11-dodecadien-1-yl acetate (80 : 20 trans : cis). Minor components identified were trans 9-dodecen-1-yl acetate, 11-dodecen-1-yl acetate, and dodecan-1-yl acetate.     

Field work in Romania: Introduction

Conclusions An even broader theoretical conclusion is in order. The term modernization has been enshrined in the value-free literature on development which the Western academy has created and supported. But the experience of Brasov, a local manifestation of Romanian development, makes it clear that modernization is by no means confined to Western assumptions, and that it always occurs in specific ways depending on the social situation of the society undergoing change, and on the political nature of the program being adopted. In short, socialist modernization in Romania is not parallel to modernization under capitalist auspices in analogous areas.     

Patient-orientated gastroenterology.

Analysis of the first year''s working of a combined gastroenterology clinic in a district hospital has shown that the major benefit was improved patient management. Hospital attendances were reduced, the diagnostic process accelerated, and unnecessary radiological investigations and surgical operations avoided. There were no obvious major disadvantages.     

ERYTHROID AND GRANULOCYTE-MACROPHAGE PROGENITOR CELLS IN PRE-NATAL 'STEEL' (SlJ/SlJ) ANAEMIC MICE

The erythropietin sensitivities of dissociated cell cultures and explanted fragments of fetal livers of congenitally anaemic Sl^J/Sl^J mice, and their normal littermates, have been compared. The erythropoietin responsiveness of Sl^J/Sl^J foetal liver cells is deficient in both types of culture. The maximum liver complement of erythroid colony forming cells (CFUe) occurs on the 16th day of development when ‘normal’ livers contain approximately 6 × 10⁵ erythroid colony forming cells/liver. In Sl^J/Sl^J fetuses the maximum reached is only 1 × 10⁵. Granulocyte-macrophage colony forming cells (CFU_C) in Sl^J/Sl^J fetal livers are also reduced to approximately 60% of normal numbers. Erythroid colony forming cells are also reduced in the spleen and femoral bone marrow of Sl^J/Sl^J mice in the 2–3 days preceding birth. Granulocyte-macrophage colony forming cells are rare in the femoral marrow of pre-natal Sl^J/Sl^J mice, but their production in the Sl^J/Sl^J pre-natal spleen appears unaffected.