D-glucosamine propanedithioacetal, an efficient chiral auxiliary in beta-lactam chemistry.

The synthesis of some monocyclic beta-lactams (monobactams) by the Staudinger reaction using D-glucosamine propanedithioacetal as chiral auxiliary is reported. The influence of several radicals at C3, C4, and C1' (sugar moiety) as well as other structural aspects are considered in relation to the antielastase activity.     

Local movements and population size of European eels,Anguilla anguilla,in a small lake in southwestern Spain

Synopsis Radio telemetry was used to study the movements of European eels,Anguilla anguilla, in a small (1.2 ha) lake in southwestern Spain in March and April, 1985. Observations were taken on the locations of 7 eels at least once each 2 h for a combined total of 1713 h. The size of individual activity regions varied from 2700 to 1300 m². Eels covered a larger area at night than during the day, with an average of 23% and 42% of the activity region used during the day and night respectively. Average distance moved between observations was significantly greater at night than in the day. Eels tracked during rainy and cloudy weather were more active during the day and used a larger total area than did those tracked during drier, more stable weather. The standing crop of eels was estimated to be about 77 kg ha^–1.     

Haemodynamic effects of angiotensin II in conscious, non-ascitic cirrhotic rats

The effect of angiotensin II (AII) on systemic and regional haemodynamics was studied in 18 control and 18 cirrhotic, non-ascitic conscious rats (CCl4/phenobarbital model). Cirrhotic rats were found to retain sodium and to have normal plasma renin and plasma aldosterone concentrations when compared with control animals. Cirrhotic rats showed an enhanced cardiac output (34.4 +/- 0.5 vs. 27.5 +/- 2.0 ml/min in controls) and decreased peripheral resistances (2.96 +/- 0.25 vs. 3.95 +/- 0.31 mm Hg/min/100 g/ml in controls) under basal conditions. When AII was administered cardiac output decreased by 10.7 +/- 1.2% in cirrhotic rats, whereas it increased in control animals (11.2 +/- 2%, p less than 0.005). The AII-induced increase in arterial pressure was lower in cirrhotic than in control rats. The renal blood supply was particularly impaired by AII in cirrhotics, with a maintained flow to other organs (muscle, testes). It is concluded that the response to AII is disturbed in rats with hepatic cirrhosis even in a stage without ascites and with plasma renin and aldosterone concentrations similar to those of control animals.     

Absence of an endogenous regulator of Na+,K+-ATPase activity in the tissues of cirrhotic rats

Microsomal Na+,K+-ATPase isolated from the renal cortex of rats with CCL4-induced cirrhosis (CIR) showed a higher specific activity than the enzyme obtained from control rats (COR). Kinetic studies showed a lower K0.5 for ATP (0.08 +/- 0.03 vs. 0.24 +/- 0.04 mM; p less than 0.05), a lower Na+ activation constant (9.6 +/- 1.5 vs. 19.0 +/- 1.7 mM; p less than 0.05), and a higher K+ activation constant (1.2 +/- 0.1 vs. 0.6 +/- 0.1 mM; p less than 0.05) for CIR. The optimal pH of the enzyme was 0.5 units higher in CIR than COR. The fluorescence of eosin-treated enzymes indicated a higher ratio of E1/E2 forms of Na+,K+-ATPase in CIR. The K+-activated p-nitrophenylphosphatase (pNPPase) activity of the enzyme was lower in CIR than COR rats (1.5 +/- 0.1 vs. 2.2 +/- 0.1 mU/mg; p less than 0.05). Dialysing (24 h) COR microsomes reproduced most of the changes observed in CIR enzymes (kinetics, optimal pH, and eosin fluorescence). Lyophilized dialysate of COR, but not of CIR microsomes, inhibits Na+,K+-ATPase activity. These results suggest that a dialysable inhibitor modifies the Na+,K+-ATPase activity in the kidney of COR which is almost absent in that of CIR. The absence of this factor may lead to the overall inability to excrete Na+ in the cirrhotic state.     

Aspergilosis En Colombia

Resumen Se presentan 15 casos de aspergilosis recolectados en diferentes ciudades del país. Doce fueron casos autopsiados. Los tres restantes se refieren a pacientes en quienes se efectuó una lobectomía pulmonar superior derecha por aspergiloma gigante intracavitario. En los doce primeros existía una enfermedad básica que había alterado seriamente el estado general del paciente; once de ellos habían recibido antibióticos, cinco habían recibido esteroides, y dos, agentes citotóxicos. Se cree que, tanto el estado general del paciente, como la administración de dichas drogas, favorecieron la infección micótica. De los tres casos con aspergiloma intracavitario gigante, se cree que, en uno, la micosis se implantó en una caverna tuberculosa cicatrizada. En los otros dos, la cavidad era un bronquio localmente dilatado y se consideró que no existía una infección tuberculosa.ElAspergillus posee un amplio espectro de patogenicidad. Se le puede observar en lesiones que van desde una localización intrabronquial, acompañada de mínima o nula reacción inflamatoria, hasta casos en los cuales existen lesiones pulmonares necrotizantes con diseminación hematógena a otros órganos (sistema nervioso central, hígado, riñón).     

Age and growth of yellow eels, Anguilla anguilla, in the estuary of the Guadalquivir river (south-west Spain)

A total of 1068 eels were examined from a population located in the Guadalquivir river estuary (37°N, 6°25'W). Maximum ages recorded were 4 + (males) and 7+ (females), and maximum lengths were 39-1 cm (males) and 54.1 cm (females). No growth was recorded between November and April, most occurring in May and, to a lesser extent, in June-October. Females grew to be larger than males. A classification analysis, based on 17 different European eel populations revealed that populations in brackish waters grew faster than those in fresh waters, but latitude also had an influence. Length-weight relationships obtained for three eel categories (males, females and undifferentiated) were used to estimate relative condition: condition cycles were similar between sexes, with increases in autumn and decreases in winter. There were monthly fluctuations in the sex ratio, and females dominated significantly in the combined catch (234 males/276 females).     

Candida albicans stress mannoproteins expression in superficial and systemic candidiasis

The presence of heat shock mannoproteins (HSMPs) reactive with sIgA was demonstrated in several C. albicans strains. The subculture of the C. albicans isolated from mucosal surfaces on Sabouraud's dextrose agar at 25 °C switched off the HSMP expression. A re-expression of the HSMPs was obtained in the same medium by shifting the temperature of incubation to 37 °C. However, expression of HSMPs in two strains isolated from deep infections was maintained during several subcultures on Sabouraud's dextrose agar at 25 °C. A glycoprotein of 200 kDa seemed to be the main HSMP reacting with vaginal sIgA. The data presented in this study suggest that factors other than temperature can influence the expression of C. albicans HSMPs and therefore these antigens should be referred as stress mannoproteins.Abbreviations HSMPs heat shock mannoproteins - MAb monoclonal antibody - sIgA secretory IgA     

Molecular analysis of a microaerobically induced operon required for hydrogenase synthesis in Rhizobium leguminosarum biovar viciae

The nucleotide sequence (6138 bp) of a microaerobically inducible region (hupV/VI) from the Rhizobium leguminosarum bv. viciae hydrogenase gene cluster has been determined. Six genes, arranged as a single operon, were identified, and designated hypA, B, F, C, D and E based on the sequence similarities of all of them, except hypF, to genes from the hydrogenase pleiotropic operon (hyp) from Escherichia coli. The gene products from hypBFCDE were identified by in vivo expression analysis in E. coli, and their molecular sizes were consistent with those predicted from the nucleotide sequence. Transposon Tn5 insertions into hypB, hypF, hypD and hypE resulted in R. leguminosarum mutants that lacked any hydrogenase activity in symbiosis with peas, but still were able to synthesize the polypeptide for the hydrogenase large subunit. The gene products HypA, HypB, HypF and HypD contained CX₂C motifs characteristic of metal-binding proteins. In addition, HypB bore a long histidine-rich stretch of amino acids near the N-terminus, suggesting a possible role in nickel binding for this protein. The gene product HypF, which was translationally coupled to HypB, presented two cysteine motifs (CX₂CX₈₁CX₂C) with a capacity to form zinc finger-like structures in the N-terminal third of the protein. A role in nickel metabolism in relation to hydrogenase synthesis is postulated for proteins HypB and HypF.     

Effect of propranolol on glycerol induced acute renal failure in rats

The effect produced by propranolol, administered for a prolonged period of time and in large doses, on renal function in rats has been studied, as well as the modifications induced by this treatment in an experimental model of acute renal failure, and the effects of a single dose of propranolol given 1 hour before provoking failure. Propranolol, administered chronically, causes sodium and water retention and increases creatinine clearance. Acute renal failure induced by glycerol in rats treated for 7 days with propranolol is less severe than the one produced in untreated animals. In this ARF model, a single dose of propranolol does not seem to have a protective effect.     

Expression of multiple Na+,K(+)-ATPase genes reveals a gradient of isoforms along the nonpigmented ciliary epithelium: functional implications in aqueous humor secretion.

The Na+,K(+)-ATPase alpha 1, alpha 2, and alpha 3 subunit isoforms have been shown to be differentially expressed in the nonpigmented (NPE) and pigmented (PE) cells of the ocular ciliary epithelium (CE) (Martin-Vasallo et al., J. Cell. Physiol., 141:243-252, 1989; Ghosh et al., J. Biol. Chem., 265:2935-2940, 1990). In this study we analyzed and compared the pattern of expression of the multiple Na+,K(+)-ATPase alpha (alpha 1, alpha 2, alpha 3) subunit genes with the pattern of expression of the Na+,K(+)-ATPase beta (beta 1, beta 2) subunit genes along the bovine CE. We have selected three regions in the CE, referred to as 1) the anterior region of the pars plicata, near the iris; 2) the middle region of the pars plicata; and 3) the posterior region of the pars plana, near the ora serrata. Using isoform-specific cDNA probes and antibodies for the Na+,K(+)-ATPase alpha 1, alpha 2, alpha 3, beta 1, and beta 2 subunits on Northern and Western blot analysis, we found that mRNA and polypeptides are expressed in all three CE regions with different abundance. The pattern of expression of alpha and beta isoforms detected along the NPE cell layers suggests a gradient of alpha 1, alpha 2, alpha 3, beta 1, and beta 2 mRNAs and polypeptides that correlates with decreasing Na+,K(+)-ATPase activity from the most anterior region at the pars plicata towards the posterior region at the ora serrata. We also found marked differences in the pattern of immunolocalization of Na+,K(+)-ATPase alpha 1, alpha 2, alpha 3, beta 1, and beta 2 subunit isoforms in different regions of the CE. In the anterior region, NPE cells stained intensely at the basal lateral membrane with specific monoclonal and polyclonal antibodies for each of the alpha (alpha 1, alpha 2, alpha 3) and beta (beta 1, beta 2) Na,K-ATPase isoforms. In the middle and posterior regions of the CE, NPE cells showed lower or absent levels of staining with alpha 1, alpha 2, alpha 3, and beta 1 antibodies, although staining with beta 2 was abundant. In contrast, PE cells throughout the CE were stained at the basal lateral membrane by antibodies to alpha 1 and beta 1, while no staining signals were detected with the rest of the antibodies (i.e. alpha 2, alpha 3, and beta 2). Our results support the conclusion that the three alpha and two beta isoforms of the Na+,K(+)-ATPase are differentially expressed in the two cell layers that make up the CE.(ABSTRACT TRUNCATED AT 250 WORDS)