Proteolytic processing of chromogranin B and secretogranin II by prohormone convertases

Two experimental approaches were used to study the processing of chromogranin B and secretogranin II by prohormone convertases. In GH3 cells various prohormone convertases were overexpressed together with the substrate chromogranin B by use of a vaccinia virus infection system. PC1 appeared to be by far the most active enzyme and converted chromogranin B to several smaller molecules, including the peptide PE-11. In brain this peptide is cleaved physiologically from chromogranin B. Some processing of chromogranin B and formation of free PE-11 were also observed with PC2 and PACE4. Furin produced larger fragments, whereas PC5-A and PC5-B had negligible effects. As a second model, PC12 cells were stably transfected with PC1 or PC2 to investigate the processing of endogenous chromogranins. Both enzymes effectively cleaved chromogranin B and secretogranin II, liberating the peptides PE-11 and secretoneurin, respectively. However, in transfection experiments the ability to generate the free peptides was more pronounced with PC2 than with PC1. The extent of proprotein processing achieved by prohormone convertases apparently differed depending on the experimental system applied. This suggests that in vivo mechanisms to support and fine-tune the activity of the processing enzymes exist, which might be overlooked by using only one methodological approach.     

Kinetic mechanism of Escherichia coli asparagine synthetase B

Escherichia coli asparagine synthetase B (AS-B) catalyzes the synthesis of asparagine from aspartate, glutamine, and ATP. A combination of kinetic, isotopic-labeling, and stoichiometry studies have been performed to define the nature of nitrogen transfer mediated by AS-B. The results of initial rate studies were consistent with initial binding and hydrolysis of glutamine to glutamate plus enzyme-bound ammonia. The initial velocity results were equally consistent with initial binding of ATP and aspartate prior to glutamine binding. However, product inhibition studies were only consistent with the latter pathway. Moreover, isotope-trapping studies confirmed that the enzyme-ATP-aspartate complex was kinetically competent. Studies using 18O-labeled aspartate were consistent with formation of a beta-aspartyl-AMP intermediate, and stoichiometry studies revealed that 1 equiv of this intermediate formed on the enzyme in the absence of a nitrogen source. Taken together, our results are most consistent with initial formation of beta -aspartyl-AMP intermediate prior to glutamine binding. This sequence leaves open many possibilities for the chemical mechanism of nitrogen transfer.     

Serological properties of HIV-1 isolates from the focus of an epidemic in the Gomel region of the Belarus Republic (1996)

Immunoreactivity of sera obtained in 1996 from HIV-1-infected intravenous narcomaniacs from an epidemic focus in Gomel region, Belarus, is studied with a panel of 10-16-component synthetic peptides simulating apical epitope of surface glycoprotein gp120 V3 loop of HIV-1 variants. Comparative analysis of resultant spectra with representative immunoreactivity spectra of sera from a sampling of HIV-1-positive sera collected in 1986-1997 in different regions of the former USSR demonstrated a high homogeneity of immunoreactivity spectra of sera from Gomel region. Serotypes of HIV-1 A/C variants circulating in populations of intravenous narcomaniacs in the focus in Gomel region in 1996 and in Southern and South-Eastern Ukraine in 1995-1996 are similar. This confirms a previous conclusion about the prevalence of A/C serotype among intravenous narcomaniacs in the former USSR.     

Fate of the upper urinary tract in multiple sclerosis

The Staphylococcus aureus 8325-4 hyaluronate lyase gene (hysA) was identified after detecting hyaluronate lyase activity expressed by phages from a genomic library. The hysA open reading frame, capable of encoding a protein of 91 980 Da, was identified by Tn5 mutagenesis and nucleotide sequencing. HysA shares 35 and 36% amino acid sequence identity with group B streptococcal hyaluronate lyase and pneumococcal hyaluronidase, respectively. A 94-kDa protein was expressed in Escherichia coli minicells, a result consistent with the coding capacity of hysA. Identification of the S. aureus 8325-4 hyaluronate lyase gene will allow the regulation of this putative virulence determinant to be studied.     

Characterization of Plasmodium falciparum glutamate dehydrogenase-soluble antigen

There are limited data on the factors associated with menopausal hot flashes, a common and potentially morbid condition. The objective of this study was to identify predictors of menopausal hot flashes. To meet this objective, 233 naturally perimenopausal or post-menopausal women (ages 45-65) attending a large urban hospital center primary care clinic, mammography unit, or women's health practice were enrolled. The women responded to a self-administered questionnaire assessing selected demographic factors, reproductive history, and behavioral factors. Sixty-seven percent of respondents experienced hot flashes, with 63% reporting frequent hot flashes (at least one hot flash per day) and 60% with hot flashes describing the hot flashes as severe. Women with hot flashes were significantly more likely to have mothers who experienced hot flashes (OR = 4.4, CI = 2.0-10.0) or to be smokers (OR = 2.0, CI = 1.2-3.5). There were no statistically significant associations between hot flashes and other selected demographic, reproductive, or behavior characteristics. These results reveal that menopausal hot flashes are associated with a maternal history of hot flashes as well as with cigarette smoking. These results may help physicians to counsel their patients about smoking cessation.     

Functioning of the hypophyseal-adrenocortical system in rats selected for the sensitivity threshold to the electric current

Although behavioral and neuropsychological data regarding the existence of images for odors are inconclusive, reconsideration of earlier EEG work provides reasonably clear evidence for an inner nose. However, further EEG studies and neuroimaging data seem essential for conclusive demonstration of an inner nose.     

Relaparotomy]

The study of intrarenal and upper urinary tracts urodynamics in the presence of the ureteropelvic obstruction and of the function of the lower urinary tract shows that congenital hydronephrosis was in 42.8% of cases associated with bladder dysfunction presenting with hyperreflex-type dysfunction. Maladapted hyperreflex bladder was diagnosed in 29.4%, adapted--in 13.5% of cases. The hyporeflex dysfunction occurred in 15.9% of cases. The urinary bladder dysfunction in children with congenital hydronephrosis accounts for 58.7%. These aggravate the same defects of the upper urinary tracts and deteriorate the course of chronic obstructive pyelonephritis.     

Concurrent abomasal displacement and perforating ulceration in cattle: 21 cases (1985-1996)

OBJECTIVE: To evaluate the association of physical examination and clinicopathologic findings with surgical findings in cattle with concurrent abomasal displacement and perforating ulceration, to determine short- and long-term survival rates in these cattle, and to determine whether degree of peritonitis (focal vs diffuse) influences survival rates. DESIGN: Retrospective study. ANIMALS: 21 cattle with concurrent abomasal displacement and perforating ulceration and 42 cattle with uncomplicated abomasal displacement. PROCEDURE: Information on signalment, stage of lactation, physical examination findings, clinicopathologic data, surgical diagnosis, procedure(s) performed, and necropsy findings were retrieved from medical records of all cattle included in this study. Differences between physical examination findings of cattle with concurrent disease and those of cattle with uncomplicated displacements were evaluated, as were differences between survival rates in cattle with focal versus diffuse peritonitis. RESULTS: Cattle with concurrent disease had a greater probability of having pneumoperitoneum and signs of abdominal pain identified on physical examination than did cattle with uncomplicated diseases. There was no relationship between clinicopathologic data and survival time. Short-term survival rate was 38%, and degree of peritonitis significantly influenced survival time in cattle with concurrent abomasal displacement and perforating ulceration. Long-term survival rate in these cattle was 14%. CLINICAL IMPLICATIONS: Cattle with concurrent displaced abomasum and perforating ulceration have a poor chance for survival. In addition to detection of displaced abomasum, physical examination findings that can help lead to a presurgical diagnosis of this syndrome are pneumoperitoneum and signs of abdominal pain.     

Fluoro-Green and Fluoro-Red: two new fluorescent retrograde tracers with a number of unique properties

A sample of 443 Pakistani infants from four different socioeconomic areas was followed longitudinally study the emergence of the primary teeth. The mean ages of emergence of the primary teeth, without regard what kind of tooth and dental ages of the primary teeth were calculated. The subjects showed no sexual dimorphism in the emergence times of the primary teeth. The children from poor areas. were ahead by statistically significant differences from upper middle class, for emergence of the primary teeth 17-20. On comparison with Swedish standards (H?gg & Taranger, 1985) Pakistani children are delayed, by a statistically significant difference, in the emergence of primary teeth 1-16, however, they were at par in the emergence of 17-20 primary teeth.