HIV-1 virion fusion assay: uncoating not required and no effect of Nef on fusion

We recently described a sensitive and specific assay that detects the fusion of HIV-1 virions to a broad range of target cells, including primary CD4 cells. This assay involves the use of virions containing beta-lactamase-Vpr (BlaM-Vpr) and the loading of target cells with CCF2, a fluorogenic substrate of beta-lactamase. Since Vpr strongly associates with the viral core, uncoating of the viral particle might be required for effective cleavage of CCF2 by BlaM-Vpr. Here, we show that BlaM-Vpr within mature viral cores effectively cleaves CCF2, indicating that this assay measures virion fusion independently of uncoating. We also show that wildtype and Nef-deficient HIV-1 virions fuse with equivalent efficiency to HeLa-CD4 cells, SupT1 T cells, and primary CD4 T cells. Since Nef enhances cytoplasmic delivery of viral cores and increases viral infectivity, these findings indicate that Nef enhances an early post-fusion event in the multistep process of viral entry. Possible sites of Nef action include enlargement of the fusion pore, enhanced uncoating of viral particles, and more efficient passage of viral cores through the dense cortical actin network located immediately beneath the plasma membrane.     

Use of computed tomography in diagnosis of major postoperative gastrointestinal complications of laparoscopic Roux-en-Y gastric bypass surgery

Laparoscopic Roux-en-Y gastric bypass (LRYGB) is becoming a frequently performed procedure for the treatment of morbid obesity. It is important for all general surgeons to be able to diagnose correctly and treat its complications. It is the purpose of this study to determine whether computed tomography (CT) is useful in correctly diagnosing these complications. The medical records of all patients that underwent LRYGB between March 2000 and December 2002 (n = 574) at Huntington Memorial Hospital were reviewed. Major abdominal complications defined as anastomotic leaks or small bowel obstruction were noted. Results of CT scans in these patients were reviewed by both a radiologist and an attending surgeon. CT scan findings were then compared to intraoperative findings. Postoperatively, 18 patients were found to have small bowel obstruction/herniation and anastomotic leaks. CT scan correctly diagnosed anastomotic leaks and small bowel obstruction in 71 per cent and 100 per cent of patients, respectively. Complication following LRYGB are rare but potentially life-threatening. CT scans are helpful in predicting the pathology and directing the surgical management of these patients. CT scan findings, however, can be subtle and therefore be missed by those not intimately familiar with post gastric bypass anatomy.     

Perinatal mortality in a Swedish county 1973-1978. Time trends revealed by perinatal audit

The decline in perinatal mortality in a Swedish county during a six year period is examined and analyzed by use of perinatal audit. The decline coincided with an increased rate of in utero transfers of infants, particularly those with low birth weights, to the specialized county hospital. The perinatal audit revealed that the proportion of deaths which were classified as potentially avoidable, decreased significantly over the study period.     

A client-centred approach to developing assistive technology with children

In a large research project a client-centred approach was employed to gain critical judgements from children with physical disabilities. Eighty-four children helped guide the design of a new adaptive pediatric seating system. This was achieved through the implementation of a unique protocol to learn what children like and dislike about specific features of adaptive seating systems. This protocol, which may also be useful in a clinical setting, was found to be reliable and valid for obtaining perspectives from children with physical disabilities. Copyright © 1996 Whurr Publishers Ltd.     

Reduced growth of human sarcoma xenografts in hosts homozygous for the lit mutation

BACKGROUND AND OBJECTIVES: Prior studies have shown that sarcoma growth can be stimulated by insulin-like growth factor-I (IGF-I). To extend this line of research, we carried out in vivo growth studies of primary human sarcoma in immunosuppressed control and IGF-I-deficient mice. METHODS: Human sarcoma specimens (one osteosarcoma and seven soft tissue sarcomas) were harvested in the operating room and implanted in immunosuppressed mice. Second-generation sarcomas were transplanted to control (GH replete lit/+ mice) and to experimental (GH/IGF-I-deficient lit/lit) animals. When tumors reached 1,000 mm(3) in one group, average tumor size was compared in the two groups. IGF-I receptor expression was measured by RT-PCR and IGF-I receptor binding sites were assayed by radiolabeled IGF-I. RESULTS: Five of eight sarcomas demonstrated reduced growth in the GH/IGF-I-deficient lit/lit animals. In four of the five sarcomas that demonstrated growth inhibition, IGF-R was elevated relative to placenta or a positive control cell line (MCF-7, which is known to be responsive to IGF-I in vitro and in vivo). In three of the five sarcomas that demonstrated growth suppression, IGF-R was elevated twofold after implantation in the experimental IGF-I-deficient animals. CONCLUSIONS: The GH-IGF axis may be an important stimulator of tumor growth in sarcomas. These experiments suggest that IGF suppression may inhibit sarcoma growth in vivo.     

Carcinoembryonic antigen (CEA), alphafetoprotein (AFP) alpha and beta subunits of human chorionic gonadotropin (hCG) in cerebrospinal fluid of children with acute lymphoblastic leukaemia

The cerebrospinal fluid (CSF) and plasma levels of CEA, AFP, alpha and beta hCG were determined by radioimmunoassay in 19 children with acute lymphoblastic leukaemia (ALL). CSF in 15 patients at the onset of ALL was examined in the first week after diagnosis and subsequently every two months. In 4 other children in second complete remission of ALL, CSF was examined every two months as well. Elevated values of CEACSF were present in 1/15 patients at the onset of ALL, of AFPCSF 0/15, alpha hCGCSF in 2/15, beta hCGCSF in 2/15 cases. The elevated levels of these markers in CSF became normal in successive lumbar punctures and none of these children developed central nervous system (CNS) relapse in further follow-up. Isolated CNS relapses were diagnosed 13 times in 7 children. Elevated CEACSF levels were found in 6/13 cases (maximum, 25.0 ng/ml) and in one patient CEACSF levels correlated well with pleocytosis. Elevated AFPCSF values were present in 0/13 cases, alpha hCGCSF in 0/13 and beta hCGCSF in 3/13 patients and became normal by the next CSF examination. The determination of CEA, AFP, alpha and beta hCG in plasma did not play a role in monitoring CNS relapse in ALL patients.     

Increased substance P expression in the trochanteric bursa of patients with greater trochanteric pain syndrome

Greater trochanteric pain syndrome (GTPS) is a pathology that can involve the trochanteric bursa or the tendons which attach to the greater trochanter. To clarify the potential importance of bursa versus tendon pathology and of substance P (SP) in contributing to pain in this condition tendon and bursa tissue biopsies were obtained from 34 patients with GTPS and 29 control subjects. Specimens were evaluated via light microscopy for histopathological and morphological differences, as well as using immunohistochemistry for macrophages (CD68), inflammatory cells (CD45) and SP. Bursa [stroma score, mean (SD): 4.18 (1.65) vs. 2.53 (1.61), p = 0.051] and tendon [Bonar score, mean (SD): GTPS mean (SD) 12.65 (2.0), control (10.43 (4.84), p = 0.04] from subjects with GTPS demonstrated more extensive signs of pathology than specimens from control subjects. There was a significantly greater presence of SP in the bursa (frequency: 9/12 vs. 6/16, p = 0.047), but not in the tendon (8/12 vs. 8/15, p = 0.484) of subjects with GTPS compared to controls. An increased presence of SP in the trochanteric bursa may be related to the pain associated with GTPS.     

Increased glutathione S-transferase activity rescues dopaminergic neuron loss in a Drosophila model of Parkinson's disease

Loss-of-function mutations of the parkin gene are a major cause of early-onset parkinsonism. To explore the mechanism by which loss of parkin function results in neurodegeneration, we are using a genetic approach in Drosophila. Here, we show that Drosophila parkin mutants display degeneration of a subset of dopaminergic (DA) neurons in the brain. The neurodegenerative phenotype of parkin mutants is enhanced by loss-of-function mutations of the glutathione S-transferase S1 (GstS1) gene, which were identified in an unbiased genetic screen for genes that modify parkin phenotypes. Furthermore, overexpression of GstS1 in DA neurons suppresses neurodegeneration in parkin mutants. Given the previous evidence for altered glutathione metabolism and oxidative stress in sporadic Parkinson's disease (PD), these data suggest that the mechanism of DA neuron loss in Drosophila parkin mutants is similar to the mechanisms underlying sporadic PD. Moreover, these findings identify a potential therapeutic approach in treating PD.     

Hotspots and the conservation of evolutionary history

Species diversity is unevenly distributed across the globe, with terrestrial diversity concentrated in a few restricted biodiversity hotspots. These areas are associated with high losses of primary vegetation and increased human population density, resulting in growing numbers of threatened species. We show that conservation of these hotspots is critical because they harbor even greater amounts of evolutionary history than expected by species numbers alone. We used supertrees for carnivores and primates to estimate that nearly 70% of the total amount of evolutionary history represented in these groups is found in 25 biodiversity hotspots.