Long-term survival in children under 3 years of age with low-grade astrocytoma

Objective The purpose of this study is to analyze clinical aspects and disease-free survival (DFS) in children less than 3 years of age diagnosed with low-grade astrocytoma. Methods In a period of 24 years (1980–2004), a total of 43 (5.4%) children were registered with these characteristics. Twenty-three patients had pilocytic astrocytoma, 18 diffused, and 2 mixed. Thirty-one (72.1%) children had incomplete surgical tumor resection and 12 (27.9%) had a complete tumor resection. Twelve (27.9%) patients had cranial radiotherapy and 17 (39.5%) received chemotherapy. Overall survival was recorded in 23 (53%). DFS was 50% at 250 months of follow-up for the whole group. DFS for the supratentorial group was 60% at 250 months, whereas, for the infratentorial, it was 22% at 120 months (p = 0.008). Conclusion The only favorable prognostic pattern was the supratentorial presentation. Radiotherapy and chemotherapy did not alter the outcome.     

Truncation mutants define and locate cytoplasmic barriers to lateral mobility of membrane glycoproteins.

The lateral mobility of cell membrane glycoproteins is often restricted by dynamic barriers. These barriers have been detected by measurements of fluorescence photobleaching and recovery (FPR) and barrier-free path (BFP). To define the location and properties of the barriers, we compared the lateral mobility, measured by FPR and BFP, of wild-type class I major histocompatibility complex (MHC) membrane glycoproteins with the lateral mobility of mutant class I MHC glycoproteins truncated in their cytoplasmic domains. Mutants with 0 or 4 residues in the cytoplasmic domain were as mobile as lipid-anchored class I MHC molecules, molecules whose lateral mobility is relatively unrestricted by barriers. In contrast, mobility of class I MHC molecules with 7-residue cytoplasmic domains was as restricted as mobility of class I molecules with full-length, 31-residue cytoplasmic domains. Though some of the difference between the mobilities of mutants with 4- or 0-residue domains and the other class I molecules may be due to differences in the net charge of the cytoplasmic domain, FPR measurements of the mobility of molecules with 7-residue domains show that length of the cytoplasmic domain has an important influence on the lateral mobility. Model calculations suggest that the barriers to lateral mobility are 2-3 nm below the membrane bilayer.     

A pox on thee! Manipulation of the host immune system by myxoma virus and implications for viral-host co-adaptation

The poxviruses have evolved a diverse array of proteins which serve to subvert innate and adaptive host responses that abort or at least limit viral infections. Myxoma virus and its rabbit host are considered to represent an ideal poxvirus-host system in which to study the effects of these immunomodulatory proteins. Studies of laboratory rabbits (Oryctolagus cuniculus) infected with gene knockout variants of myxoma virus have provided compelling evidence that several myxoma virus gene products contribute to the pathogenic condition known as myxomatosis. However, myxomatosis, which is characterized by skin lesions, systemic immunosuppression, and a high mortality rate, does not occur in the virus' natural South American host, Sylvilogus brasiliensis. Moreover, in Australia where myxoma virus was willfully introduced to control populations of O. cuniculus, myxomatosis-resistant rabbits emerged within a year of myxoma virus introduction into the field. In this review I discuss the characterized immunomodulatory proteins of myxoma virus, their biochemical properties, their pathogenic effects in laboratory rabbits, the role of the host immune system in the susceptibility or resistance to myxomatosis, and the evidence that immunomodulatory genes may have been attenuated during the co-adaptation of myxoma virus and O. cuniculus in Australia.     

Phosphatidylglycerolphosphate synthase encoded by the PEL1/PGS1 gene in Saccharomyces cerevisiae is localized in mitochondria and its expression is regulated by phospholipid precursors

The PEL1/PGS1 gene of the yeast Saccharomyces cerevisiae is essential for the viability of rho ^–/rho° mutants and the normal cardiolipin content of cells. The PEL1-GFP fusion gene has been found to complement the pel1/pgs1 mutation and its fluorescent protein was localized to mitochondria similarly to the β-galactosidase activity of a protein encoded by the PEL1-lacZ fusion gene. The expression of the PEL1-lacZ reporter gene was repressed in cells grown in the presence of inositol and choline, reduced in the ino2 and ino4 strains, but constitutive in the opi1 null-mutant strain. The results demonstrate that Pel1p, playing a vital role in cells impaired in the mitochondrial DNA, is localized in the mitochondria and expressed in response to inositol and choline. Received: 15 June / 15 July 1998     

Localization of the Antigen and Antibodies in the Placenta of Immunized Sheep

ABSTRACT: Placentomata of sheep immunized with human serum albumin (HSA) were examined. Both HSA and immunoglobulins were found in the maternal part and maternofetal border of the placenta using FITC labelled antisera on paraffin sections. Radiolabelled HSA was also detected in the fetal blood. The ultrastructure of placentomata revealed immunopathological process.     

Genetic diversity among clinical isolates of Candida glabrata analyzed by randomly amplified polymorphic DNA and multilocus enzyme electrophoresis analyses

The genetic diversity of 47 clinical and reference strains of Candida glabrata from several geographical origins and diverse clinical disorders, with different antifungal susceptibilities, as well as their genetic relationships were studied through multilocus enzyme electrophoresis (MLEE) and randomly amplified polymorphic DNA (RAPD) techniques. The genetic diversity estimated for 11 MLEE loci measured as average heterozygosity (h) was 0.055. A high level of genetic relatedness among isolates was established by cluster analysis. Forty-nine RAPD markers were analyzed, and the average genetic diversity among isolates, estimated by Shannon's index (Ho), was 0.372. The PhiST values estimated through an analysis of molecular variance to assess genetic differentiation among isolates revealed no genetic differentiation among them. Our results revealed very low genetic diversity among isolates, a lack of differentiation, and no association with their geographic origin and the clinical characteristics.     

Heat-shock protein (HSP70-2) allelic frequencies in three distinct Mexican populations

The major histocompatibility complex (MHC) genes are highly polymorphic and therefore have been useful in population genetics and disease association studies. We analyzed restriction fragment length polymorphism of HSP70-2 alleles in healthy unrelated Mestizo, Mazatecan and Nahua populations. Both Indian groups, Mazatecans and Nahuas, were in Hardy-Weinberg equilibrium, while Mestizos were in disequilibrium (chi 2 = 0.399; P < 0.05). The Mazatecan Indians presented a high frequency of BB homozygosity (17.35%) compared to Mestizos (5%) (P = 0.01). Mexican ethnic groups present differences in distribution of BB genotype. The low frequency of BB genotype in Mestizos may be the result of a negative selection process.     

Plasma testosterone and catecholamine responses to physical exercise of different intensities in men

Summary Plasma testosterone, noradrenaline, and adrenaline concentrations during three bicycle ergometer tests of the same total work output (2160 J·kg^–1) but different intensity and duration were measured in healthy male subjects. Tests A and B consisted of three consecutive exercise bouts, lasting 6 min each, of either increasing (1.5, 2.0, 2.5 W·kg^–1) or constant (2.0, 2.0, 2.0 W·kg^–1) work loads, respectively. In test C the subjects performed two exercise bouts each lasting 4.5 min, with work loads of 4.0 W·kg^–1. All the exercise bouts were separated by 1-min periods of rest.Exercise B of constant low intensity resulted only in a small increase in plasma noradrenaline concentration. Exercise A of graded intensity caused an increase in both catecholamine levels, whereas, during the most intensive exercise C, significant elevations in plasma noradrenaline, adrenaline and testosterone concentrations occurred. A significant positive correlation was obtained between the mean value of plasma testosterone and that of adrenaline as well as noradrenaline during exercise.It is concluded that both plasma testosterone and catecholamine responses to physical effort depend more on work intensity than on work duration or total work output.This work was performed within the Scientific Exchange Programme between the Institute of Experimental Endocrinology, Slovak Academy of Sciences in Bratislava and Medical Research Centre, Polish Academy of Sciences, Warsaw/Project 10.4/     

Ureaplasma urealyticum infection in newborns: Three case reports

We report three newborns with different manifestations ofUreaplasma urealyticum infection; a term newborn with acute neonatal pneumonia and two very low birth weight infants with bronchopulmonary dysplasia and osteomyelitis of the femur, respectively. The association ofU. urealyticum with acute and chronic respiratory disease in term and preterm newborns has recently been reported. Our two cases are similar to other case reports from the literature, but we were unable to find any previous reports of osteomyelitis due toU. urealyticum in the premature babies. Isolation ofU. urealyticum in pure culture from the blood was considered to be related to local infection in all three patients. All patients were cured by erythromycin.