Evaluation of a new enzyme-linked immunosorbent assay test for rotavirus antigen in faeces

A new commercial test for the diagnosis of rotavirus gastroenteritis was assessed. With some modifications it compared favourably with electron microscopy and immunofluorescence.     

Competitive control of the self-renewing T cell repertoire

We develop a mathematical model for the self-renewing part of the T cell repertoire. Assuming that self-renewing T cells have to be stimulated by immunogenic MHC-peptide complexes presented on the surfaces of antigen-presenting cells, we derive a model of T cell growth in which competition for MHC-peptide complexes limits T cell clone sizes and regulates the total number of self-renewing T cells in the animal. We show that for a sufficient diversity and/or degree of cross-reactivity, the total T cell number hardly depends upon the diversity of the T cell repertoire or the diversity of the set of presented peptides. Conversely, for repertoires of lower diversity and/or cross-reactivity, steady-state total T cell numbers may be limited by the diversity of the T cells. This provides a possible explanation for the limited repertoire expansion in some, but not all, mouse T cell re-constitution experiments. We suggest that the competitive interactions described by our model underlie the normal T cells numbers observed in transgenic mice, germ-free mice and various knockout mice.      

Immunological studies with different classes of mutants affected at the adenosine kinase locus in CHO cells

Adenosine kinase (AK) from CHO cells has been purified to homogeneity and specific antibodies to it have been raised in rabbits. Using this antibody, the presence of a specific cross-reacting protein (CRP) in cell extracts of different classes of mutants resistant to purine nucleoside analogs which are affected in AK has been investigated by the immunoblotting technique. Results of our studies show that 31 of the 32 independently selected class A AK^– mutants (obtained at high frequency in presence of adenosine analogs toyocamycin, tubercidin, 6-methylmercaptopurine riboside, or pyrazofurin and containing no measurable activity of AK in cell extracts) contained similar amounts of a specific CRP as seen in the parental AK⁺ cells. The CRP in the parental and different mutant cell lines has the same relative molecular mass as purified AK. Similar results were obtained with two mutants each of the class B and C type (selected in presence of C-nucleosides formycin A and formycin B), which are also affected in AK but show novel properties. The presence of equivalent amounts of the CRP in the vast majority of the class A mutants strongly indicates that the high frequency of those mutants in CHO cells is not a result of an epigenetic or deletion type of event, but that such mutants may contain missense types of mutations at a presumed mutational hot spot within the structural gene for adenosine kinase.     

Viral load responses to HAART is an independent predictor of a new AIDS event in late stage HIV infected patients: prospective cohort study

Background  

A sizeable number of HIV-infected patients receiving HAART do not maintain prolonged virologic suppression. We evaluated long-term HIV viral load (VL) responses to HAART as a risk factor for AIDS events (AE) that is independent of CD4 responses.     

Transfer of zona-free embryos improves outcome in poor prognosis patients: a prospective randomized controlled study

Assisted zona hatching (AZH) has been used in IVF programmes for several years. Recently one group has reported successful pregnancies after transfer of zona-free blastocysts. The aim of our study was to evaluate outcomes after transfer of zona-free day 3 embryos. Two groups of women undergoing intracytoplasmic sperm injection (ICSI) were included in the study. Group A consisted of 52 women under the age of 40 years undergoing their first ICSI attempt. They were alternately randomized to receive zona-free embryos (27 women) and zona-intact embryos (25 women). The second group (group B) included 71 women with a poor prognosis, as defined by age 40 years or more, and/or at least two previous failed IVF/ICSI attempts. They were randomized in a 3:4 ratio (30 zona-free, 41 zona-intact). Acid Tyrode's solution was used to remove the zona pellucida before embryo transfer on day 3 after oocyte collection. The pregnancy rate in group A was not significantly improved when the zona pellucida was removed. However, in the poor prognosis group B, zona removal resulted in a significantly higher pregnancy rate when compared with controls (23 versus 7.3%). We conclude that complete removal of the zona pellucida can improve pregnancy rates in women with poor IVF/ICSI prognosis.     

A synthetic nanofibrillar matrix promotes in vivo-like organization and morphogenesis for cells in culture

The purpose of this study was to design a synthetic nanofibrillar matrix that more accurately models the porosity and fibrillar geometry of cell attachment surfaces in tissues. The synthetic nanofibrillar matrices are composed of nanofibers prepared by electrospinning a polymer solution of polyamide onto glass coverslips. Scanning electron and atomic force microscopy showed that the nanofibers were organized into fibrillar networks reminiscent of the architecture of basement membrane, a structurally compact form of the extracellular matrix (ECM). NIH 3T3 fibroblasts and normal rat kidney (NRK) cells, when grown on nanofibers in the presence of serum, displayed the morphology and characteristics of their counterparts in vivo. Breast epithelial cells underwent morphogenesis to form multicellular spheroids containing lumens. Hence the synthetic nanofibrillar matrix described herein provides a physically and chemically stable three-dimensional surface for ex vivo growth of cells. Nanofiber-based synthetic matrices could have considerable value for applications in tissue engineering, cell-based therapies, and studies of cell/tissue function and pathology.     

Granulomatous Pneumocystis carinii pneumonia complicating hematopoietic cell transplantation

Pneumocystis carinii pneunonia (PCP) is associated with a wide spectrum of clinical and histopathological presentations. While granulomatous PCP uncommonly occurs in AIDS patients, it is extremely rare in other non-AIDS immunocompromised patients. We identified three patients who developed granulomatous PCP after bone marrow or blood stem cell transplantation. In all cases, fiberoptic bronchoscopy with bronchoalveolar lavage was non-diagnostic, and an open lung biopsy was required for diagnosis. All patients were successfully treated with trimethoprim-sulfamethoxazole. The histological appearance varied from an ill-defined granulomatous pneumonia to well-formed necrotizing granulomas. The typical intraalveolar eosinophilic frothy exudate was absent. Often sparsely distributed, the organisms were detected by GMS and immunohistochemical stains for P. carinii. No other pathogens were identified by additional histochemical stains or by microbiological cultures. Awareness of this unusual granulomatous tissue response to P. carinii and initiation of specific treatment can lead to successful resolution of this potentially lethal infection.     

ICSI using testicular sperm in male hypogonadotrophic hypogonadism unresponsive to gonadotrophin therapy

BACKGROUND: The aim of this study was to assess the use of testicular sperm for ICSI in azoospermic men with hypogonadotrophic hypogonadism unresponsive to gonadotrophin therapy. METHODS: Fifteen patients with hypogonadotrophic hypogonadism who remained azoospermic after hormonal treatment underwent testicular sperm extraction (TESE) and ICSI. These men were recruited from the Egyptian IVF centre over a period of 4 years. All patients were given 75 IU hMG thrice weekly and 5000 IU hCG once or twice weekly for >/=6 months prior to attempting ICSI/TESE. RESULTS: In 11 out of 15 patients (73%), sperm could be retrieved from testicular tissue and were used for ICSI. Two chemical pregnancies resulted but no clinical pregnancies. Nine patients continued gonadotrophin therapy for another 6 months. Sperm appeared in the ejaculate of three of them. The remaining six patients underwent another ICSI cycle, one using cryopreserved sperm and five underwent a second TESE. One chemical pregnancy and three clinical pregnancies were established. One ongoing, one singleton and one twin pregnancies resulted in the delivery of three healthy babies. In total, of 17 ICSI cycles performed using testicular sperm retrieval, the fertilization rate was 41.7% and the cumulative pregnancy rate was 20%. CONCLUSIONS: The use of testicular sperm for ICSI is a treatment option that can be offered to azoospermic males with hypogonadotrophic hypogonadism either not responding or reluctant to continue hormonal treatment. However, prolonged hormonal treatment may improve TESE/ICSI results.