Restriction enzyme analysis of faecal adenoviruses in Newcastle upon Tyne

Adenovirus DNA was isolated directly from virus-containing stools and digested with restriction endonucleases. The resulting fragments were separated by polyacrylamide gel electrophoresis (PAGE) and visualized by silver staining. This enabled us to assign most of the viruses detected to subgenus, serotype and, sometimes, unique strains. Although less sensitive than electron microscopy, the method allowed more information about the infecting virus to be obtained and no cultivation was necessary. Comparison with culture also allowed dual infections to be recognized. A 2-year survey of faecal adenoviruses in Newcastle upon Tyne showed that type 41 (strain 41a) was the predominant type and strain 41p was not recorded. Heterogeneity in strain 41a was also noted as found elsewhere. Adenovirus type 40 was common prior to 1985 but was absent during the last 2 years.     

Voltage Oscillations in Xenopus Spinal Cord Neurons: Developmental Onset and Dependence on Co-activation of NMDA and 5HT Receptors

The development of intrinsic, N-methyl-D-aspartate (NMDA) receptor-mediated voltage oscillations and their dependence on co-activation of 5-hydroxytryptamine (5HT) receptors was explored in motor neurons of late embryonic and early larval Xenopus laevis. Under tetrodotoxin, 100 μM NMDA elicited a membrane depolarization of around 20 mV, but did not lead to voltage oscillations. However, following the addition of 2–5 μM 5HT, oscillations were observed in 12% of embryonic and 70% of larval motor neurons. The voltage oscillations depended upon co-activation of NMDA and 5HT receptors since they were curtailed by selectively blocking NMDA receptors with D-2-amino-5-phosphonovaleric acid (APV) or by excluding Mg²⁺ from the experimental saline. 5HT applied in the absence of NMDA also failed to elicit oscillations. Oscillations could be induced by the non-selective 5HT_1a receptor agonist, 5-carboxamidotryptamine (5CT) and both 5HT- and 5CT-induced oscillations were abolished by pindobind-5HT₁, a selective 5HT_1a receptor antagonist. To test whether 5HT enables voltage oscillations by modulating the voltage-dependent block of NMDA channels by Mg²⁺, membrane conductance was monitored under tetrodotoxin. Although 5HT caused membrane hyperpolarization of 4–8 mV, there was little detectable change in conductance. NMDA application caused an approximate 20 mV depolarization and an ‘apparent’ decrease in conductance, presumably due to the conductance pulse bringing the membrane into a voltage region where Mg²⁺ blocks the NMDA ionophore. 5HT further decreased conductance, which we propose is due to its enhancement of the voltage-dependent Mg²⁺ block. When the membrane potential was depolarized by ～20 mV via depolarizing current injection (to mimic the NMDA-induced depolarization), 5HT increased rather than decreased membrane conductance. Furthermore, 5HT did not affect the increase in membrane conductance following NMDA applications in zero Mg²⁺ saline. The results suggest that intrinsic, NMDA receptor-mediated voltage oscillations develop in a brief period after hatching, and that they depend upon the co-activation of 5HT and NMDA receptors. The enabling function of 5HT may involve the facilitation of the voltage-dependent block of the NMDA ionophore by Mg²⁺ through activation of receptors with 5HT_1a-like pharmacology.     

Renal transplantation performed across a positive crossmatch: A single centre experience

The importance of certain positive crossmatches (CM⁺) in kidney transplantation remains controversial. Fifty consecutive kidney transplants were performed across a CM⁺ between Jan. 1990 – April 1994. In 19 cases there was an isolated B-cell CM⁺ (Group I), in 24 an historic T-cell IgM CM⁺ (Group II) and in 7 an historic T-cell IgG CM⁺ (Group III). Comparing groups I:II:III: early acute rejection affected 32%, 42%, 57% of grafts; mean serum creatinine at 3 months was 166, 150, 229 umol/l (p<0.05); 1 yr graft survival was 95 per cent, 96 per cent, 71 per cent (p=0.09). In group III both graft losses were in the setting of an additional current B-cell CM⁺. Conclusions: Transplantation performed in either the presence of an isolated B-cell CM⁺ or in the presence of an historic T-cell IgM CM⁺ was associated with acceptable outcomes at 1 yr. An historic T-cell IgG CM⁺ was confirmed as a contraindication to transplantation in most circumstances, especially when coupled with a current B-cell CM⁺.     

IgA-epidermolysis bullosa acquisita in a child resulting in blindness

Epidermolysis bullosa acquisita (EBA) is an acquired subepidermal bullous disease characterized by IgG autoantibodies directed against type VII collagen, the major component of anchoring fibrils. The classical phenotype of EBA is a non-inflammatory, mechanobullous disease resembling the dystrophic forms of inherited epidermolysis bullosa. Mucous membrane involvement is frequent but usually mild. We report a 1-year-old girl suffering from IgA-EBA, who presented with an initial eruption of disseminated urticarial lesions and tense blisters of the skin but subsequently developed severe oral and ocular lesions reminiscent of cicatricial pemphigoid. Direct immunofluorescence of the skin and buccal mucosa revealed linear IgA and C3 at the basement membrane zone (BMZ). IgA anti-BMZ autoantibodies stained the dermal side of salt-split skin by indirect immunofluorescence and recognized a dermal protein of 290 kDa co-migrating with type VII collagen by immunoblotting. Direct and indirect immunoelectron microscopy revealed IgA deposits overlying the anchoring fibrils. The ocular involvement led to total blindness in spite of intense treatment. This case of childhood IgA-EBA is particularly striking because of the cicatricial pemphigoid phenotype with severe ocular involvement which resulted in blindness. It reinforces the necessity to use modern immunological methods to classify autoimmune bullous diseases in order to allow early and appropriate treatment.     

The effects of a 0.12% chlorhexidine-digluconate-containing mouthrinse versus a placebo on plaque and gingival inflammation over a 3-month period

Abstract Several previous studies have evaluated the effects of 0.12% chlorhexidine digluconate (ChD) mouthrinses on plaque and gingival inflammation. However, previously, none have been based in general dental practices. The aim of this study was to evaluate the potential to conduct controlled periodontal clinical trials in co-operation with general dental practitioners (gdps). The project took place in 5 general dental practices in the South of England. 121 healthy subjects (24 at 4 sites and 25 at the 5th). aged 18-65 years, mean 35 ± 12) years participated in a double-blind, randomised study during which they received full mouth assessments for plaque and gingival bleeding at baseline, 6 and 12 weeks. 60 subjects were randomly asigned to use the 0.12% ChD mouth wash and 6i the placebo. The assessments were carried out by 5 gpds, who had previously achieved inter-examiner κ scores of 0.78–0.85 (mean 0.81) for the plaque index (PlI), and of 0.73–0.94 (mean 0.87) for a modified gingival index (mGI), and who maintained κ scores of 0.51–0.90 for PII and of 0.73–1.00 for mGI during the 12 months required to complete the study. 98 subjects (48 ChD and 50 placebo) completed the study. Even though the baseline levels of plaque and gingivitis were low, by week 12, mean whole mouth piaque score of the ChD mouthwash users had fallen from 1.33 at baseline to 0.96 and was significantly lower (p < 0.001) than for the placebo users, 1.31 at baseline to 1.13. Whole-mouth gingival bleeding score fell from 0.56 to 0.42 in the ChD mouthwash group but was unchanged (0.54–0.55) in the placebo group. A subsidiary data analysis which considered the effects at sites indicated that within these overall differences, the ChD users experienced almost 2× the reduction from plaque score 2 at baseline at proximal molar sites over a 12-week period (50.6% ChD versus 27.6% placebo). It was concluded that 0.12% ChD mouthwash reduced plaque accumulation fay 28% and gingival inflammation by 25% over a 12–week period, that it is feasible for a group of gdps to maintain high levels of inter–examiner consistency in the use of PlI and mGI, that it is also feasible to carry out such a multicentre study in general dental practice, and that the use of mean mouth scores per subject to analyse the effects of mouthrinses may well mask variations in response throughout the mouth.