Cryptosporidium suis n. sp. (Apicomplexa: Cryptosporidiidae) in pigs (Sus scrofa)

Molecular and biological characteristics of a new species of Cryptosporidium from the feces of pigs (Sus scrofa) is described. Oocysts are structurally indistinguishable from those of Cryptosporidium parvum; they are passed fully sporulated, lack sporocysts, and measure 4.9-4.4 microm (mean = 4.6 microm) x 4.0-4.3 microm (mean = 4.2 microm); length to width ratio 1.1 (n = 50). Cryptosporidium suis is not transmissible to nude mice and is poorly infectious for cattle. Molecular and phylogenetic analyses at the 18S ribosomal RNA, heat shock protein 70, and actin gene loci demonstrate C. suis to be genetically distinct from all known species and genotypes of Cryptosporidium, and thus is named as Cryptosporidium suis.     

Upregulation of collecting duct aquaporin-2 by metabolic acidosis: role of vasopressin

Metabolic acidosis is associated with alteration in fluid and electrolyte reabsorption in a number of nephron segments. However, the effects of metabolic acidosis on urine osmolality and aquaporin-2 (AQP-2) remain poorly understood. In these studies, we examined the effects of chronic metabolic acidosis on water handling by the kidney. Rats were placed in metabolic cages and subjected to water (control) or 280 mM NH₄Cl loading for 120 h to induce metabolic acidosis. The results indicated a significant increase in urine osmolality with no change in urine volume or urinary Na⁺ excretion in acid-loaded animals. This effect was independent of alteration in fluid intake or salt/Cl^- loading. Immunoblotting and Northern hybridization studies indicated that AQP-2 protein abundance and mRNA expression levels increased significantly along the collecting duct system of NH₄Cl-but not NaCl-loaded animals. RIA results indicated that metabolic acidosis was associated with a fourfold increase in circulating levels of vasopressin (AVP) and a significant increase in brain AVP mRNA expression levels. In conclusion, metabolic acidosis upregulates the expression levels of AQP-2 and increases urine osmolality, suggesting an adaptive increase in water reabsorption in the collecting duct. A concomitant increase in AVP synthesis and secretion likely plays an essential role in the adaptation of AQP-2 in metabolic acidosis. kidney; acid-base; urine osmolality; sodium excretion rate     

De novo design, synthesis, and in vitro activity of LFA-1 antagonists based on a bicyclic[5.5]hydantoin scaffold

LFA-1 (leukocyte function-associated antigen-1), is a member of the beta(2)-integrin family and is expressed on all leukocytes. The LFA-1/ICAM interaction promotes tight adhesion between activated leukocytes and the endothelium, as well as between T cells and antigen-presenting cells. Evidence from both animal models and clinical trials provides support for LFA-1 as a target in several different inflammatory diseases. This paper describes the de novo design, synthesis and in vitro activity of LFA-1 antagonists based on a bicyclic[5.5]hydantoin scaffold.     

High-efficient <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated <Emphasis Type="Italic">in planta</Emphasis> transformation in black gram (<Emphasis Type="Italic">Vigna mungo</Emphasis> (L.) Hepper)

In vitro culture and genetic transformation of black gram are difficult due to its recalcitrant nature. Establishment of gene transfer procedure is a prerequisite to develop transgenic plants of black gram in a shorter period. Therefore, genetic transformation was performed to optimize the factors influencing transformation efficiency through Agrobacterium tumefaciens-mediated in planta transformation using EHA 105 strain harbouring reporter gene, bar, and selectable marker, gfp-gus, in sprouted half-seed explants of black gram. Several parameters, such as co-cultivation, acetosyringone concentration, exposure time to sonication, and vacuum infiltration influencing in planta transformation, have been evaluated in this study. The half-seed explants when sonicated for 3 min and vacuum infiltered for 2 min at 100 mm of Hg in the presence of A. tumefaciens (pCAMBIA1304– bar) suspensions and incubated for 3 days co-cultivation in MS medium with 100 µM acetosyringone showed maximum transformation efficiency (46 %). The putative transformants were selected by inoculating co-cultivated seeds in BASTA^® (4 mg l^?1) containing MS medium followed by BASTA^® foliar spray on 15-day-old black gram plants (35 mg l^?1) in green house, and the transgene integration was confirmed by biochemical assay (GUS), Polymerase chain reaction, Dot-blot, and Southern hybridisation analyses.     

Structure of myohemerythrin in the azidomet state at 1.7/1.3 A resolution

The molecular model of myohemerythrin, an oxygen-carrying protein from sipunculan worms, has been refined by stereochemically restrained least-squares minimization at 1.7/1.3 A resolution to a conventional R-value of 0.158. The estimated positional standard deviation is better than 0.15 A for most of the 979 protein atoms. The average isotropic displacement parameter, B, for the protein atoms is 23.1 A2. This high average B parameter appears to be due to the overall motion of the molecule, which correlates with the observed anisotropic diffraction. The side-chains of seven residues were modeled in two conformations, i.e. the side-chains were discretely disordered, and B parameters for several lysine and glutamate side-chains indicate that they are poorly localized. Of the residues in myohemerythrin, 66% are helical, with 62% occurring in four long alpha-helices with mean values for the backbone torsion angles of phi = -65 degrees, psi = -42 degrees, and for the hydrogen bonds distances of N ... O, 3.0 A and H ... O, 2.1 A, and angles of N ... O = C, 153 degrees, N-H ... O, 157 degrees, and H ... O = C, 147 degrees. For two-thirds of the alpha-helical residues, the torsional rotation of the C alpha-C beta bond, chi 1, is approximately -60 degrees, and for one-third chi 1 is approximately 180 degrees. Although most turns in myohemerythrin are well-categorized by previous classification, two do not fit in established patterns. Also included in the refined model are three sulfate ions, all partially occupied, and 157 water molecules, 40% of which are modeled fully occupied. Only one water molecule is internal to the protein, the remainder occur on the surface and are observed principally between symmetry-related molecules contributing, along with van der Waals' contacts, most of the interactions between molecules. There are eight intermolecular protein-protein hydrogen bonds, of which only four are between well-located atoms.     

Cocrystals of yeast cytochrome c peroxidase and horse heart cytochrome c

Yeast cytochrome c peroxidase and horse heart cytochrome c have been cocrystallized in a form suitable for x-ray diffraction studies and the structure determined at 3.3 A. The asymmetric unit contains a dimer of the peroxidase which was oriented and positioned in the unit cell using molecular replacement techniques. Similar attempts to locate the cytochrome c molecules were unsuccessful. The peroxidase dimer model was subjected to eight rounds of restrained parameters least squares refinement after which the crystallographic R factor was 0.27 at 3.3 A. Examination of a 2Fo-Fc electron density map showed large "empty" regions between peroxidase dimers with no indication of cytochrome c molecules. Electrophoretic analysis of the crystals demonstrated the presence of the peroxidase and cytochrome c in an approximate equal molar ratio. Therefore, while cytochrome c molecules are present in the unit cell they are orientationally disordered and occupy the space between peroxidase dimers.     

Unusual joining sites in the H and L chains of an anti-lysozyme antibody

Nucleotide sequences of HyHEL-5, an antibody specific for chicken lysozyme (HEL), indicated unusual joins in the third complementarity-determining region of both the H and L chains. The VK-JK recombination site is unusual in that codon 96, normally derived from the JK gene segment, is deleted entirely, making the L3 one amino acid shorter than normal. Examination of the HyHEL-5 Fab-HEL x-ray structure suggests that the conformation of L3 is clearly important for Ag specificity. A comparison of the HyHEL-5 L3 with that of the structurally related antibody J539 indicates that the deleted residue significantly alters the conformation of the L3 turn. The H chain VH-DH join is also unusual; the VH junction site has probably occurred between the second and third nucleotides of codon 92, with the addition of five random nucleotides that encode for unusual amino acids Leu93 and His94. Although the conformation of H3 is different from what would be predicted from other H3 conformations and is clearly important to the complementarity of HyHEL-5 to HEL, the specific residues at the VH-DH join do not appear to directly contribute to Ag binding. It is not possible to attribute the main chain conformation of H3 to the particular sequence produced by the join; the structural features of H3 may be due to interactions with HEL and/or with other antibody residues.     

Sexual Dysfunction in Heroin Dependents: A Comparison between Methadone and Buprenorphine Maintenance Treatment

Introduction

Methadone has long been regarded as an effective treatment for opioid dependence. However, many patients discontinue maintenance therapy because of its side effects, with one of the most common being sexual dysfunction. Buprenorphine is a proven alternative to methadone. This study aimed to investigate sexual dysfunction in opioid-dependent men on buprenorphine maintenance treatment (BMT) and methadone maintenance treatment (MMT). The secondary aim was to investigate the correlation between sexual dysfunction and the quality of life in these patients.

Methods

Two hundred thirty-eight men participated in this cross-sectional study. Four questionnaires were used, the Mini International Neuropsychiatric Interview, Opiate Treatment Index, Malay version of the International Index of Erectile Function 15 (Mal-IIEF-15), and World Health Organization Quality of Life-BREF Scale. Multivariate analysis of covariance was used to examine the relationship between MMT and BMT and the Mal-IIEF 15 scores while controlling for all the possible confounders.

Results

The study population consisted of 171 patients (71.8%) on MMT and 67 (28.2%) on BMT. Patients in the MMT group who had a sexual partner scored significantly lower in the sexual desire domain (p < 0.012) and overall satisfaction (p = 0.043) domain compared with their counterparts in the BMT group. Similarly, patients in the MMT group without a sexual partner scored significantly lower in the orgasmic function domain (p = 0.008) compared with those in the BMT group without a partner. Intercourse satisfaction (p = 0.026) and overall satisfaction (p = 0.039) were significantly associated with the social relationships domain after adjusting for significantly correlated sociodemographic variables.

Conclusions

Sexual functioning is critical for improving the quality of life in patients in an opioid rehabilitation program. Our study showed that buprenorphine causes less sexual dysfunction than methadone. Thus, clinicians may consider the former when treating heroin dependents who have concerns about sexual function.     

The metabolic response to exercise in chronic alcoholics

The metabolic response to steady exercise was studied in six chronic alcoholics and six normal control subjects. Higher concentrations of lactated and pyruvate were observed in the alcoholics during exercise and they also developed post-exercise ketosis. These changes were probably not due to reduced fitness of the alcoholics as the heart rates of both groups were similar. Alcoholics had lower levels of growth hormone during exercise compared with the controls suggesting that chronic alcohol consumption has a depressor effect on pathways regulating the release of growth hormone.