Plasma endothelin 1/2 levels in healthy blood donors as measured by RIA--a clinical application.

Normal endothelin 1/2 levels and their correlation with age were evaluated. For clinical application of the endothelin 1/2 RIA test, optimum storage conditions were investigated. Plasma endothelin 1/2 (ET) levels were measured in 36 healthy blood donors, mostly males, of mean age 36 +/- 8 years, subdivided into three age groups: 17-30, 31-40 and above 40 years old. The mean normal ET levels in the three age groups, and corresponding standard deviations, were: 0.58 +/- 0.19, 0.62 +/- 0.31, and 0.80 +/- 0.28 fmol/ml, respectively. The mean ET level for the whole normal population was 0.66 +/- 0.28 fmol/ml. Only differences between mean ET levels for the first and last groups were statistically significant (p < 0.05). Differences between mean ET levels in smokers (53% of total population) and non-smokers, women and men, irrespective of age, were found not to be statistically significant. At this stage of our work, we conclude that other factors than age alone play a role in enhancing ET levels above the age of 41 years. In our study of optimum storage conditions for endothelin 1/2, we found that after one week of storage at -24 degrees C the mean level of ET measured in frozen plasma dropped to 85% of the initial activity, while after the same period the respective decrease in ET activity in frozen extracts was 49%. Over the next two weeks, ET levels in plasma and extracts dropped to 57% and 32% of "zero time" activities, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Superiority of magnetic resonance imaging (MRI) over computerized tomography (CT) in diagnosis of hypopituitarism]

Hypopituitarism can be a result of various lesions of hypothalamus, pituitary stalk, or of the pituitary gland itself. The aim of the study was to assess the value of CT and MRI examinations in determination of the cause of hypopituitarism. Seventeen patients with hypopituitarism (9 women and 8 men) aged 22 to 61 years have been examined. In three cases growth deficiency was observed, 4 women had galactorrhoea, 4 patients had diabetes insipidus, 16 patients had supra-adrenal insufficiency, 14 had signs of hypogonadism and 10 hypothyroidism. In each case plasma concentrations of LH, FSH, PRL, TSH, alpha-subunit, ACTH before and after appropriate stimulation with TRH, metoclopramid, LH-RH, GRF or metyrapon were determined with RIA. Every patient was examined both with CT and MRI (0.5 T Toshiba MRT 50a). All 17 patients had abnormal MR images of hypothalamo-pituitary area, while only 10 of them had abnormalities in their CT scans. In remaining 7 patients the MRI revealed: three cases of congenital malformation of hypophyseal stalk, two cases of empty sella, one posttraumatic lesion of the stalk and one case of granulomatous infiltration of the stalk. We found MRI superior to CT in establishing the case of hypopituitarism.     

Sensitive chemiluminescent detection of digoxigenin-labeled nucleic acids: a fast and simple protocol and its applications.

A fast and simple protocol for the chemiluminescent detection of digoxigenin-labeled nucleic acids with anti-digoxigenin antibody Fab fragments coupled to alkaline phosphatase and 3-(4-methoxyspiro[1,2-dioxetane-3,2'-tricyclo-[3.3.1.1 (3,7)]decan]-4- yl)phenyl phosphate as substrate is described. The washing and blocking procedure was optimized to yield low background even on positively charged nylon membranes. The sensitivity of the system is equal or better than radioactive methods. Exposure to x-ray or Polaroid film for up to 30 minutes is sufficient for the detection of 70 femtograms of homologous DNA. Human single-copy genes are detected in Southern blots of as low as 0.3 microgram total placental DNA. Blots can be reprobed multiple times very easily. The advantages of the digoxigenin system are high sensitivity, absence of background and ease of reprobing and are illustrated by applications for single-copy gene detection in genomic blots of human DNA, Northern hybridizations to rare mRNA, detection of E. coli genes on blots of genomic digests after pulse field gel electrophoresis, as well as for nonradioactive DNA sequencing blots with digoxigenin-labeled primers.     

The multiple-minima problem in small peptides revisited. The Threshold Accepting approach.

A recently reported optimization method, known as Threshold Accepting, was tested for the purpose of locating the structure of several peptide molecules with the lowest conformational energy. A comparison with previous results obtained with the Simulated Annealing technique was made. Our study indicate Threshold Accepting as a better technique in locating such structures.     

Cloning of human lysyl hydroxylase: complete cDNA-derived amino acid sequence and assignment of the gene (PLOD) to chromosome 1p36.3----p36.2.

Lysyl hydroxylase (EC 1.14.11.4), an alpha 2 dimer, catalyzes the formation of hydroxylysine in collagens by the hydroxylation of lysine residues in peptide linkages. A deficiency in this enzyme activity is known to exist in patients with the type VI variant of the Ehlers-Danlos syndrome, but no amino acid sequence data have been available for the wildtype or mutated human enzyme from any source. We report the isolation and characterization of cDNA clones for lysyl hydroxylase from a human placenta lambda gt11 cDNA library. The cDNA clones cover almost all of the 3.2-kb mRNA, including all the coding sequences. These clones encode a polypeptide of 709 amino acid residues and a signal peptide of 18 amino acids. The human coding sequences are 72% identical to the recently reported chick sequences at the nucleotide level and 76% identical at the amino acid level. The C-terminal region is especially well conserved, a 139-amino-acid region, residues 588-727 (C-terminus), being 94% identical between the two species and a 76-amino-acid region, residues 639-715, 99% identical. These comparisons, together with other recent data, suggest that lysyl hydroxylase may contain functionally significant sequences especially in its C-terminal region. The human lysyl hydroxylase gene (PLOD) was mapped to chromosome 1 by Southern blot analysis of human-mouse somatic cell hybrids, to the 1p34----1pter region by using cell hybrids that contain various translocations of human chromosome 1, and by in situ hybridization to 1p36.2----1p36.3. This gene is thus not physically linked to those for the alpha and beta subunits of prolyl 4-hydroxylase, which are located on chromosomes 10 and 17, respectively.     

Effects of recombinant human extracellular-superoxide dismutase type C on myocardial infarct size in pigs.

The efficacy of human extracellular-superoxide dismutase type C (EC-SOD C) to limit infarct size after ischemia and reperfusion was explored and compared to that of EC-SOD C combined with catalase (CAT) and to that of CAT alone. EC-SOD C binds to heparan sulphate proteoglycan on the cell surfaces. Thirty-two pigs were subjected to 45 min of myocardial ischemia followed by 4 h of reperfusion. Control pigs (group A; n = 8) received 300 mL of saline into the great cardiac vein during a 30-min period started 5 min prior to reperfusion; pigs in group B (EC-SOD C; n = 8) got 16.6 mg of EC-SOD C; pigs in group C (EC-SOD C + CAT; n = 8) got 16.6 mg of EC-SOD C together with 150 mg of CAT. Pigs in group D (CAT; n = 8) received 150 mg of CAT. In groups B, C, and D, the drug was dissolved in saline and infused into the great cardiac. Infarct size expressed as percent of area at risk was smaller in groups B (14.5 +/- 16.7%) and C (40.8 +/- 13.3%) than in groups A (78.8 +/- 8.6%) and D (67.2 +/- 18.6%; p less than .05). Creatine kinase (CK) activity in ischemic myocardium was higher in groups B (1740 +/- 548 U/g) and C (1729 +/- 358 U/g) than in groups A (1184 +/- 237 U/g) and D (1251 +/- 434 U/g; p less than .05). There was an inverse relation (r = -.83) between infarct size and CK content. The EC-SOD C infusions resulted in only minimal increases in plasma SOD activities. In conclusion, the presence of SOD on the cell surfaces is of importance in the prevention of reperfusion injury rather than circulating SOD.     

Infraciliature, morphogenesis and life cycle of Endosphaera terebrans (Suctoria, Tokophridae)

The morphology, infraciliature, and life cycle of Endosphaera terebrans, a suctorian endocommensal of peritrichs, have been studied with the aid of silver impregnation. The life cycle of Endosphaera terebrans begins with infection of the host cell by a small larva. The swarmer has a pointed needle-like cellular projection and two rings of cilia. The swarmer penetrates the the peritrich, loses the cilia, and then matures into an adult. The infraciliature of the adult form has four rows of barren kinetosomes that lack kinetodesmal fibers. By endogenous budding, a migratory larva is produced that leaves the host cell through the peristomial disc and that can infect other peritrichs.     

Characteristics of the microsporidian Enterocytozoon bieneusi: a consequence of its development within short-living enterocytes.

Ultrastructural studies were done on developmental stages of Enterocytozoon bieneusi obtained from HIV seropositive patients suffering from diarrhea. The presence of elaborate multilamellar structures suggest that they give rise to various membrane systems needed for rapid production of disseminating stages.