Sequence and expression of IMP-L1, an ecdysone-inducible gene expressed during Drosophila imaginal disc morphogenesis.

Drosophila imaginal discs are induced by the steroid hormone 20-hydroxyecdysone to initiate morphogenesis leading to formation of the adult appendages and thoracic epidermis at the end of the third larval instar. Ecdysone-dependent transcriptional activation of a set of genes that encode imaginal disc transcripts found on membrane-bound polysomes precedes and may be responsible for some aspects of the cellular changes that mediate epithelial morphogenesis in this system. A 1.35 kb transcript from one of these genes, IMP-L1, is first observed in vivo at or just prior to pupariation, as ecdysone titers are peaking and beginning to decline. Expression is initiated in proximal areas of the antennal disc, later spreading to a more widespread but nonuniform distribution throughout other thoracic imaginal discs. IMP-L1 is not, however, expressed in other ecdysone target tissues such as salivary glands or fat body. The IMP-L1 gene encodes a novel protein product containing a signal peptide, a possible transmembrane domain, two highly charged domains and a proline rich C-terminal domain. We suggest that the delayed timing of expression of this secondary response gene is necessary for proper ordering of cellular events associated with disc morphogenesis.

[Complex compound odontoma cystic eruption]. / Odontoma compuesto complejo quístico erupcionado.

An erupted cystic complex odontoma's case is reported. Histological, radiographic and clinic/fractures were considered. Erupted odontomas are unusual lesions; we did not find similar case reported in the literature.

A protein inhibitor of phosphofructokinase from the mucosa of rat small intestine. A mechanism for the regulation of glycolysis that is independent of glucose.

A protein inhibitor of phosphofructokinase was detected by the chromatography on Sephadex G-100 of crude mucosal extracts prepared from the small intestine of starved rats. Addition of the protein inhibitor to extracts from fed rats increased the K0.5 of phosphofructokinase for fructose 6-phosphate to that for starved rats. The protein inhibitor provides a mechanism for the hormonal regulation of glycolysis independently of glucose supply.

The acute regulation of glucose absorption, transport and metabolism in rat small intestine by insulin in vivo.

The effect of acute changes in insulin concentrations in vivo on the absorption, transport and metabolism of glucose by rat small intestine in vitro was investigated. Within 2 min of the injection of normal anaesthetized rats with anti-insulin serum, lactate production and glucose metabolism were respectively diminished to 28% and 21% of normal and the conversion of glucose into lactate became quantitative. These changes correlated with the inhibition of two mucosal enzymes, namely the insulin-sensitive enzyme pyruvate dehydrogenase, and phosphofructokinase, which was shown by cross-over measurements to be the rate-limiting enzyme of glycolysis in mucosa. The proportion of glucose translocated unchanged from the luminal perfusate to the serosal medium was simultaneously increased from 45% to 80%. All the changes produced by insulin deficiency were completely reversed with 2 min when antiserum was neutralized by injection of insulin in vivo. The absorption and transport of 3-O-methylglucose were unaffected by insulin. It is concluded that glucose metabolism in rat small intestine is subject to short-term regulation by insulin in vivo and that glucose absorption and transport are regulated indirectly in response to changes in metabolism. Moreover, transport and metabolism compensate in such a way as to deliver the maximal 'effective' amount of glucose to the blood, whether as glucose itself or as lactate for hepatic gluconeogenesis.

The effect of glucose on the activity of phosphofructokinase in the mucosa of rat small intestine.

In common with other phosphofructokinase isoenzymes, phosphofructokinase in the epithelial cells of rat small-intestinal mucosa is activated by fructose 2,6-bisphosphate. However, fructose 2,6-bisphosphate was found not to be present in mucosa as judged by three criteria: (1) chromatography on Sephadex G-25 of crude mucosal extracts from fed rats did not result in a decrease, or indeed any change, in the activity of phosphofructokinase under suboptimal conditions at pH7; (2) ultrafiltrates of mucosal extracts did not possess any acid-labile activating activity when tested against chromatographed liver phosphofructokinase; (3) phosphofructokinase-2 activity was not detectable in mucosal extracts. Furthermore, the perfusion in vitro of isolated loops of jejunum or the incubation of mucosal scrapings from either fed rats or rats starved for 48 h showed that the activity of mucosal phosphofructokinase is not subject to short-term regulation by glucose. These observations are consistent with the view that phosphofructokinase is the rate-limiting enzyme of glycolysis in intestinal mucosa and account for the fact that the rate of glucose utilization by rat small intestine is not very responsive to changes in the concentration of glucose in the lumen.

Glucose metabolism and its regulation in pieces of perirenal adipose tissue from foetal lambs.

1. The following were measured in pieces of perirenal adipose tissue obtained from foetal lambs at about 120 days of gestation or within 3 days of term, and 9-month-old sheep: the rates of synthesis from glucose of fatty acids, acylglycerol glycerol, pyruvate and lactate; the rate of glucose oxidation to CO2 and the proportions contributed by the pentose phosphate cycle, pyruvate dehydrogenase and the tricarboxylic acid cycle; the activities of hexokinase, glucose 6-phosphate dehydrogenase, phosphofructokinase, pyruvate kinase and pyruvate dehydrogenase. 2. The total rate of glucose utilization was lower in pieces of adipose tissue from near-term lambs than 120-day foetal lambs and the pattern of glucose metabolism differed, with, for example, a much smaller proportion of glucose carbon being used for fatty acid synthesis, whereas a greater proportion of glucose oxidation occurred via the tricarboxylic acid cycle in the near-term lambs. In general, these differences in glucose metabolism were not associated with differences in the activities of the various enzymes listed above. 3. The rates of glucose utilization per fat-cell by 120-day foetal lambs and 9-month-old sheep were very similar but, again, the proportions metabolized to the various products differed. In particular, there was a smaller proportion of glucose oxidized via the pentose phosphate cycle and a greater proportion oxidized via pyruvate dehydrogenase and the tricarboxylic acid cycle in adipose tissue from foetal lambs. These differences were matched by a lower activity of glucose 6-phosphate dehydrogenase and a higher pyruvate dehydrogenase activity in fat-cells from the foetal lambs.

Regulation of glycolysis and fatty acid synthesis from glucose in sheep adipose tissue.

1. The following were measured in adipose-tissue pieces, obtained from 7-9 month-old sheep, before or after the tissue pieces had been maintained in tissue culture for 24 h: the rates of synthesis from glucose of fatty acids, acylglycerol glycerol, pyruvate and lactate; the rate of glucose oxidation to CO(2); the rate of glucose oxidation via the pentose phosphate pathway; the activities of hexokinase, glucose 6-phosphate dehydrogenase, phosphofructokinase, pyruvate kinase, pyruvate dehydrogenase and ATP citrate lyase; the intra- and extra-cellular water content; the concentration of various metabolites and ATP, ADP and AMP. 2. The proportion of glucose carbon converted into the various products in sheep adipose tissue differs markedly from that observed in rat adipose tissue. 3. There was a general increase in the rate of glucose utilization by the adipose-tissue pieces after maintenance in tissue culture; largest changes were seen in the rates of glycolysis and fatty acid synthesis from glucose. These increases are paralleled by an increase in pyruvate kinase activity. There was no change in the activities of the other enzymes as measured, although the net flux through all the enzymes increased. 4. Incubation of fresh adipose-tissue pieces for 2-6h led to an increase in the affinity of pyruvate kinase for phosphoenolpyruvate. 5. The rate of pyruvate production by glycolysis was greater than the activity of pyruvate dehydrogenase of the tissue. 6. The results suggest that both pyruvate kinase and pyruvate dehydrogenase have important roles in restricting the utilization of glucose carbon for fatty acid synthesis in sheep adipose tissue.

L-Lactate as a source of carbon for fatty acid synthesis in adult and foetal sheep.

The contribution of carbon from acetate, glucose and L-lactate to fatty acid synthesis has been compared in adipose tissue from adult and foetal sheep. Adipose tissue slices were incubated with mixtures of acetate, glucose and L-lactate at concentrations found in sheep blood. Under these conditions acetate, glucose and L-lactate contributed 95, 2 and 3%, respectively, of the C2 units used for fatty acid synthesis in adipose tissue slices from adult sheep. In contrast, acetate, glucose and L-acetate provided 50, 17 and 33%, respectively, of the C2 units for fatty acid synthesis in adipose tissue slices from foetal lambs (about 30 days prior to birth). The contribution of acetate and L-lactate carbon to fatty acid synthesis varied with their concentrations over the normal physiological range at both ages. We conclude that L-lactate is normally a minor source of carbon for fatty acid synthesis in the adult sheep but is an important source in foetal lambs.

Aspects of adipose-tissue metabolism in foetal lambs.

1. The mean volume of adipocytes, the rates of fatty acid and acylglycerol glycerol synthesis from various precursors (in vitro), the rates of oxidation of acetate and glucose (in vitro) and the activities of lipoprotein lipase and various lipogenic enzymes were determined for perirenal adipose tissue from foetal lambs during the last month of gestation. 2. The fall in the rate of growth of perirenal adipose tissue during the last month of gestation is associated with a diminished capacity for fatty acid synthesis and lipoprotein lipase activity, but no change in the rate of acylglycerol glycerol synthesis was observed. There was no fall in the activities of cytosolic acetyl-CoA synthetase or the NADP-linked dehydrogenases, suggesting that the decrease in the rate of fatty acid synthesis was due to an impairment at the level of acetyl-CoA carboxylase or fatty acid synthetase. 3. The rate of fatty acid synthesis from acetate was greater than that from glucose. The rate of fatty acid synthesis from glucose per adipocyte of foetal lambs was similar to that of young sheep. The characteristic metabolism of adipose tissue of the adult sheep is thus present in the foetus, despite the relatively large amounts of glucose in the foetal 'diet'.

Determinants of job satisfaction in nursing care units.

Considerable attention has been placed on containing health care costs through structural approaches and budgetary means. Often overlooked in this process are costs associated to employee turnover and absenteeism. One of the important contributing factors to this withdrawal behavior is job satisfaction. Unfortunately few studies have explored the factors which influence the job satisfaction of health care workers. This study, using data collected from four hospitals, identifies fifteen factors that make major contributions to predicting the job satisfaction of nursing employees. This research suggests that the job satisfaction of nursing aides is influenced by procedures and practices that are organizational in their impact, by interactions with the work team and supervisor, and the daily activities of the nursing job. By understanding the interactive nature of these factors on job satisfaction, improvements in absenteeism and turnover can be realized with a reduction in personnel costs and improvements in quality of care.

Sheep mortalities associated with the blue green alga Nodularia spumigena.

In 2 field mortalities studied, sheep died and showed haemorrhage and diffuse liver necrosis after drinking water from dams containing growths of the blue green algae Nodularia. Sheep dosed with water containing N. spumigena Mert 5, 9 and 18 days after collection from one of the farm dams developed pyrexia and leucopenia before death. At necropsy, these sheep showed extensive haemorrhage, accumulations of yellow fluid in body cavitis and acute hepatic necrosis. Guinea pigs dosed with the water 9 days after collection died and developed periacinar liver necrosis, but those dosed 12 days after collection did not.