Muscle strength in healthy white and Asian subjects: the relationship of quadriceps maximum voluntary contraction to age, sex, body build and vitamin D

1. The maximum voluntary isometric contraction (MVC) of the dominant quadriceps muscle was measured in 136 healthy White and 172 healthy Hindu Asian subjects resident in London, using a specially designed chair equipped with a force measuring load cell. 2. Males were stronger than females, and for both sexes MVC declined with age. From age 20 to 60 the annual decline in MVC ranged from 0.56% in White males to 1.5% in female Asians. 3. White subjects were stronger than Asian subjects even after correcting for the effect of age, height, weight and sex in a multi-factorial analysis. 4. Only in males did MVC correlate with height and weight. Asian women were more obese than any other group, and showed an increase in body mass index with age. 5. Twenty-two per cent of Asian subjects had marked vitamin D deficiency (plasma 25-hydroxycholecalciferol less than 10 nmol/1). There was no correlation between MVC, and plasma 25-hydroxycholecalciferol.     

Reliable and reproducible LightCycler qPCR for HIV-1 DNA 2-LTR circles

Highly active anti-retroviral therapy (HAART) has reduced the plasma load of HIV-1 to undetectable levels. It has however failed to eliminate the virus from other body compartments. Current methods for monitoring persistent viral replication in HIV-1+ patients require a large amount of blood and/or repeated tissue biopsies. Furthermore, some of the viral reservoirs, such as brain and eye, are inaccessible for sampling. The detection of episomal HIV-1 DNA 2-LTR circles in CD4+ cells is indicative of recent, acute infection events. This paper describes a reliable and reproducible LightCycler-based assay for the quantitative measurement of HIV-1 DNA 2-LTR circles in human peripheral blood mononuclear (PBMN) cells. It details the modifications to the DNA extraction procedure and to the LightCycler PCR procedure that were required to achieve this. This new surrogate marker of persistent viral replication can now be reliably, reproducibly and robustly used to study the clinical progress of large numbers of patients whose plasma HIV-1 RNA has been reduced to undetectable levels by anti-retroviral drugs.     

Immunomodulatory and antimicrobial non-mulberry Antheraea mylitta silk fibroin accelerates in vitro fibroblast repair and regeneration by protecting oxidative stress

The antimicrobial nature of Antharaea mylitta silk-fibroin (SF) is reported but antioxidant potential and the immunomodulatory role towards the fibroblast cell repair process is not explored. Polyurethane is reported to have inflammatory potential by mononuclear cells directed cytokine release, which can guide fibroblast repair. Present study demonstrates the conjunctive effect of inflammatory PU/SF to regulate the favorable shift from pro-inflammatory to anti-inflammatory cytokine stimulation for accelerated fibroblast repair. Minimal inhibitory concentration of SF was determined against pathogenic strains and the effect of SF was investigated for fibroblast NIH3T3 cell adhesion. SF doses (8, 8.5, 9 mg mL⁻¹) were found to be greater than both the IC₅₀ of DPPH scavenging and the ED₅₀ for NIH3T3 proliferation. Anti-lipid peroxidase (ALP) activity of SF doses and citric acid-treated NIH3T3 cells were compared under hydrogen peroxide (H₂O₂) induced oxidative stress. 9 mg mL⁻¹ SF showed greater ALP activity than the citric acid standard. SF-driven protection to oxidative damage was measured by viable cell fraction in trypan blue dye exclusion assay where 9 mg mL⁻¹ SF showed the highest viability (p ≤ 0.05). 9 mg mL⁻¹ SF was blended with PU for scaffold (w/v = 2 : 5, 2 : 7, 2 : 9) fabrication. The protective effect of PU/SF (2 : 5, 2 : 7, 2 : 9) against oxidative stress was verified by damaged cell survival in MTT assay and DNA quantification. The highest number of cells survived on PU/SF (2 : 9) at all intervals (p ≤ 0.01) upon oxidative damage; PU/SF (2 : 9) was also fabricated by employing the immobilization technique. Immobilized PU/SF (2 : 9) exhibited a greater zone of microbial inhibition, a higher extent of inhibition to microbial adherence, and caused more LDH release from bacterial cell membrane due to membrane rupture, resulting in bacterial cell death (E. coli, K. pneumoniae, P. aeruginosa, S. aureus) compared to the experimental results shown by blended PU/SF (2 : 9). The protective nature of PU/SF (2 : 9) against oxidative stress was ensured through the LDH activity of damaged NIH3T3 cells. Initial raised IL-6, TNF-alpha (pro-inflammatory cytokines) and lowered IL-8, IL-10 (anti-inflammatory cytokine) profiles coupled with fallen IL-6, TNF-alpha, and elevated IL-8, IL-10 at later hours synergistically progress the inflammatory phase of in vitro scratch wound repair in mononuclear culture treated by PU/SF (2 : 9).

Initially SF accelerated pro-inflammatory cytokines, restricted anti-inflammatory cytokines; later it regulated in reverse order. SF potentially eradicated ROS and promoted Ki-67 cellular regeneration whereas pristine PU could not.     

Anti-Kaposi’s Sarcoma and Antiangiogenic Activities of Sulfated Dextrins

Delivery of the sulfated polysaccharide dextrin 2-sulfate by the intraperitoneal route to the lymphatic circulation resulted in a clinically significant improvement in Kaposi's sarcoma in three patients. Our in vitro studies show that although sulfated dextrins do not interfere with the growth of isolated human umbilical vein endothelial cells, they do inhibit the morphological differentiation of endothelial cells into tubes as well as reduce new vessel formation in a placental angiogenesis assay. The antiangiogenic effect of dextrin 6-sulfate is greater than that of dextrin 2-sulfate and is independent of their anti-human immunodeficiency virus type 1 activities.     

HIV-1-associated thrombocytopenia. The role of splenectomy.

Thrombocytopenic purpura is a common hematologic abnormality occurring in individuals infected with the human immunodeficiency virus, HIV-1. Of the nearly two million people infected with HIV-1, approximately 11% have platelet counts of less than 100,000/mm3. If no etiology other than HIV-1 infection can be found for the thrombocytopenia, the syndrome is referred to as HIV-1-associated thrombocytopenia (HAT). Steroids lead to an improvement in the platelet count in 60% to 80% of effected individuals but the majority of those who respond cannot maintain a normal platelet count when steroids are withdrawn. Furthermore concern over chronic steroid therapy in HIV-1-infected individuals has led to the investigation of other forms of treatment for this syndrome. This report describes the experience at Duke University Medical Center with eight patients who developed HAT and subsequently underwent splenectomy. In this group there was 1 complete response, 5 partial responses, and 2 patients who did not respond. There were no perioperative deaths and minimal perioperative morbidity. No evidence for the progression of HIV-1 infection in asymptomatic patients after splenectomy to AIDS related complex (ARC) or to the acquired immune deficiency syndrome (AIDS) was seen. In addition no increase in the susceptibility to infections by encapsulated organisms as a result of splenectomy was observed after a mean follow-up of 13.25 months. A review of 79 other cases reported in the literature suggests a higher response rate than that observed in our patients. Reasons for this discrepancy are discussed and an algorithm defining the role of splenectomy in the management of HAT is presented.     

Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses

The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.     

Urgent neurology out-patient referrals from primary health care physicians

We retrospectively analysed patients seen in a rapid referral clinic to identify those with abnormalities genuinely requiring urgent assessment, and to evaluate the impact of the clinic on routine services. After advertising the availability of the service, 25% of telephone referrals from primary-care physicians led to identification of patients considered suitable for urgent evaluation. We assessed 350 patients over an 18-month period. After neurological review, relevant abnormalities were identified in 73%, and 33% were considered to have warranted urgent assessment. In addition, 74% required radiological evaluation and 14% had a neurophysiological procedure; 19.4% were admitted on the same day, 13% underwent CSF analysis and 34% required some form of therapeutic intervention. In retrospect, patients with a clinical history of > 11 days rarely warranted urgent referral. Visual failure and diplopia provided the highest correlation with patients deemed to require urgent assessment, and syncope and headache the lowest. Despite the number of patients reviewed, no effect was demonstrated on waiting times for standard out-patient review.