Methylation of human T-cell leukemia virus proviral DNA and viral RNA expression in short- and long-term cultures of infected cells

Leukemic peripheral blood lymphocytes from individuals infected with the human T-cell leukemia/lymphoma virus (HTLV) were found to express little or no viral RNA before being put into tissue culture. Within 24-48 hr, viral RNA expression increased at least four- to eightfold. Established HTLV-infected cell lines constitutively express viral RNA. Southern blots of DNA from HTLV-infected cells digested with the methylation-sensitive restriction enzyme HpaII showed that the proviral DNA was methylated in all of the uncultured peripheral blood cells tested. In contrast, no proviral methylation was detected in any of the cell lines examined, suggesting a functional correlation between methylation and viral RNA expression. However, DNA from HTLV-infected lymphocytes cultured for 48 hr (by which time increases in viral RNA expression are evident) did not differ detectably with respect to proviral DNA methylation from uncultured cells, suggesting that the increase in viral RNA expression after short-term culture is mediated by mechanisms independent of changes in DNA methylation.     

Detection of a 15q deletion in a child with Angelman syndrome by cytogenetic analysis and flow cytometry

A proximal 15q deletion, del(15) (q11:q13), was detected in a child with Angelman syndrome by cytogenetic analysis of peripheral lymphocytes. The chromosomes of both parents appeared normal. Flow karyotype analysis carried out on lymphoblastoid cell lines derived from the child and her parents confirmed the presence of a de novo 15 deletion. The estimated size of the deleted segment ranged from 6.1-9.5% of chromosome 15 (approximately 6-9.3 million base pairs). The parental origin of the deleted chromosome could not be resolved by flow cytometry, but cytogenetic evidence suggested that it was derived from the smaller chromosome 15 homologue in the mother.     

Cigarette smoke prevents apoptosis through inhibition of caspase activation and induces necrosis

Emphysema is characterized by enlargement of the distal airspaces in the lungs due to destruction of alveolar walls. Alveolar endothelial and epithelial cell apoptosis induced by cigarette smoke is thought to be a possible mechanism for this cell loss. In contrast, our studies show that cigarette smoke condensate (CSC) induces necrosis in alveolar epithelial cells and human umbilical vein endothelial cells. Furthermore, study of the cell death pathway in a model system using Jurkat cells revealed that in addition to inducing necrosis, CSC inhibited apoptosis induced by staurosporine or Fas ligation, with both effects prevented by the antioxidants glutathione and dithiothreitol. Time course experiments revealed that CSC inhibited an early step in the caspase cascade, whereby caspase-3 was not activated. Moreover, cell-free reconstitution of the apoptosome in cytoplasmic extracts from CSC-treated cells, by addition of cytochrome-c and dATP, did not result in activation of caspases-3 or -9. Thus, smoke treatment may alter the levels of pro- and antiapoptogenic factors downstream of the mitochondria to inhibit active apoptosome formation. Therefore, unlike previous studies, cell death in response to cigarette smoke by necrosis and not apoptosis may be responsible for the loss of alveolar walls and inflammation observed in emphysema.     

An anti-actin monoclonal antibody inhibits the zona pellucida-induced acrosome reaction and hyperactivated motility of human sperm.

We report an inhibitory effect of an anti-actin monoclonal antibody (mAb) on the human zona pellucida (ZP)-induced acrosome reaction (AR). Motile sperm were incubated with native human ZP for 2 h in medium containing either the anti-actin mAb, an irrelevant control mAb or cytochalasins B or D (40 micromol/l). Sperm bound to the ZP were recovered and the AR was determined by fluorescein-labelled Pisum Sativum agglutinin. Anti-mouse immunoglobulin G (mIgG) Dynabeads, immunofluorescence and immunogold were used to detect the location of the anti-actin mAb in sperm. The anti-actin mAb significantly inhibited the ZP-induced AR (equivalent to cytochalasins), the ionophore A23187-induced AR and hyperactivation of sperm in medium. After incubation with anti-actin mAb, anti-mIgG beads bound to the head of >50% of sperm recovered after binding to the ZP and 10% of sperm remaining in the medium. The proportion of sperm that bound anti-mIgG beads after recovery from binding to the ZP in the presence of the anti-actin mAb was significantly correlated with the ZP-induced AR in the absence of the antibody. Immunofluorescence and immunogold demonstrated entry of the anti-actin mAb into sperm. This study suggests that the sperm plasma membrane becomes permeable to the anti-actin mAb during capacitation and initiation of the AR.     

Viral Persistence in Neurons Alters Synaptic Plasticity and Cognitive Functions without Destruction of Brain Cells

Neurons have a restricted expression of MHC heavy chain molecules which prevents presentation of antigens of infecting viruses. As a result, such infected cells escape immune surveillance and allow the establishment of noncytolytic persistent infection. Here we show that a chronic noncytolytic viral infection bothin vitroandin vivoselectively perturbed the expression of GAP-43, a protein that plays a central role in neuronal plasticity processes accompanying learning and memory. GAP-43 expression was greatly decreased in the hippocampus, an area of heightened viral replication, while synaptic density was preserved. Concurrently, the ability to learn tasks was significantly impaired in these persistently infected mice. Yet, infected neurons remained free from structural injury.     

High throughput parallel analysis of hundreds of patient samples for more than 100 mutations in multiple disease genes

As more mutations are identified in genes of known sequence, there is a crucial need in the areas of medical genetics and genome analysis for rapid, accurate and cost-effective methods of mutation detection. We have developed a multiplex allele-specific diagnostic assay (MASDA) for analysis of large numbers of samples (> 500) simultaneously for a large number of known mutations (> 100) in a single assay. MASDA utilizes oligonucleotide hybridization to interrogate DNA sequences. Multiplex DNA samples are immobilized on a solid support and a single hybridization is performed with a pool of allele-specific oligonucleotide (ASO) probes. Any probes complementary to specific mutations present in a given sample are in effect affinity purified from the pool by the target DNA. Sequence-specific band patterns (fingerprints), generated by chemical or enzymatic sequencing of the bound ASO(s), easily identify the specific mutation(s). Using this design, in a single diagnostic assay, we tested samples for 66 cystic fibrosis (CF) mutations, 14 beta-thalassemia mutations, two sickle cell anemia (SCA) mutations, three Tay-Sachs mutations, eight Gaucher mutations, four mutations in Canavan disease, four mutations in Fanconi anemia, and five mutations in BRCA1. Each mutation was correctly identified. Finally, in a blinded study of 106 of these mutations in > 500 patients, all mutations were properly identified. There were no false positives or false negatives. The MASDA assay is capable of detecting point mutations as well as small insertion or deletion mutations. This technology is amenable to automation and is suitable for immediate utilization for high-throughput genetic diagnostics in clinical and research laboratories.      

Utilization of the 2017 diagnostic criteria for hEDS by the Toronto GoodHope Ehlers–Danlos syndrome clinic: A retrospective review

The new 2017 diagnostic criteria for hypermobile Ehlers–Danlos Syndrome (hEDS) provide a framework for diagnosing hEDS but are more stringent than the previous Villefranche criteria. Our clinical experience at the GoodHope EDS clinic was that the 2017 criteria left many highly symptomatic patients without a diagnosis of hEDS. We conducted a retrospective cohort study to confirm our clinic experience and assess the accuracy of the 2017 diagnostic criteria for hEDS in patients who had a previous hEDS diagnosis based on the Villefranche criteria. Our study found that 15% (n = 20 of 131) of patients with a prior diagnosis of hEDS met the 2017 diagnostic criteria, and many of the traits used to distinguish hEDS were not significantly more frequent in patients who met 2017 criteria versus those who did not. In both groups objective systemic manifestations were found less frequently than subjective systemic manifestations. Beighton score (BS) as assessed by primary care practitioner was found to be higher than assessment by EDS practitioner in 81% (n = 74 of 91) of cases. Generalized joint hypermobility was confirmed in only 46% (n = 51 of 111) of patients who had a previous diagnosis of hEDS. Higher BS did not correlate with increased number of systemic manifestations in our cohort. Common comorbidities of hEDS were found with similar frequency in those who met 2017 criteria and those who did not. Based on our cohort, the 2017 hEDS diagnostic criteria require refinement to improve its diagnostic accuracy.     

Care of diabetic patients in hospital clinics and general practice clinics: a study in Dudley.

A five year retrospective casenote review was undertaken of 452 patients attending 11 different general practice diabetic clinics, and 506 patients attending a diabetic clinic at hospital A and 210 patients attending a diabetic clinic at hospital B. The populations attending the clinics, the degree of glycaemic control achieved and the monitoring for the development of diabetic complications were investigated. Insulin dependent patients comprised 57.9% of patients attending the diabetic clinic at hospital A, 35.7% at hospital B and 25.0% of patients attending the diabetic clinics at general practices. Of these 55.6%, 37.3% and 30.1% respectively received multiple daily insulin injections. Hospital A had a higher proportion of patients under 40 years old than hospital B or the general practice clinics. The ages of diabetic patients attending the general practice diabetic clinics were broadly similar to those attending hospital B. Significantly more general practice patients, both insulin and non-insulin dependent, had a mean blood glucose level of less than 11 mmol l-1 compared with patients attending clinics at hospitals A and B (P < 0.001). Glycosylated haemoglobin levels did not differ between patients attending hospital A and the general practice clinics. More non-insulin dependent and insulin dependent diabetic patients attending the general practice clinics and hospital A had been monitored satisfactorily for diabetic retinopathy (general practice clinic 68.8% and 39.7% respectively, hospital A 61.7% and 43.5%) than at hospital B (43.0% and 19.4%). Referral rates among all groups for ophthalmological assessment were similar.(ABSTRACT TRUNCATED AT 250 WORDS)