Synthesis of glycosaminoglycans by cultures of normal human corneal endothelial and stromal cells

Monolayer cultures of normal human corneal endothelial and stromal cells were incubated with [35S]sulfate and [3H]glucosamine for 4 hr. The labeled glycosaminoglycans resulted from this incubation were isolated from the cell layer and the growth medium and further characterized. Both endothelial and stromal cell cultures synthesized a variety of sulfated glycosaminoglycans, with chondroitin 6-sulfate as the major product. Chondroitin 4-sulfate, dermatan sulfate, and heparan sulfate were present in smaller amounts. Keratan sulfate was produced only in minimal amounts. Both cell types also synthesized hyaluronic acid. The hyaluronic acid production in stromal cell strains derived from donors of different ages was similar. The demonstration that the endothelial cell strain derived from a 1-day-old baby contained more hyaluronic acid than cultures from older donors suggests a possible age-related phenomenon as seen in developing tissues.     

Airway intervention in adult supraglottitis

Background The timing of aggressive airway intervention in adult epiglottitis is controversial. Aims To correlate Friedman’s staging of epiglottitis on admission with the airway interventions undertaken. Methods A retrospective study of 23 adult patients, mean age 51 years (range 29–81 years), who had been admitted with acute supraglottitis between March 1988 and December 2000 was undertaken. Results Three patients (13%) had airway interventions; two with tracheostomy and one with tracheal intubation. All were Friedman stage III and had rapid symptom progression during the 24 hours prior to admission. Three other stage III patients with symptom progression longer than 24 hours and all the remaining patients (stage II or less) were managed with observation and intravenous therapy. Conclusions Friedman originally advocated airway intervention in any patient stage II or worse, but this intubation threshold should probably be lowered to those patients with rapid-onset stage III (moderate respiratory distress, stridor, respiratory rate >30 per minute, pCO₂ >45mmHg) disease.     

Improving typeability of multiple bacterial species using pulsed-field gel electrophoresis and thiourea

Although pulsed-field gel electrophoresis is considered the "gold standard" technique for molecular typing, typeability may not be excellent for some bacterial species because of DNA degradation. Previous reports suggest that the addition of thiourea in the gel buffer can improved the typeability for some species. In the present study, 66 Gram-negative strains (seven species) known to be affected by DNA degradation and four control strains were evaluated by PFGE with and without the addition of 50 microg/M of thiourea to the buffer used in the electrophoresis. Macrorestriction patterns were obtained for all K. pneumoniae, S. marcescens, P. aeruginosa, and Salmonella spp., for 95.4% of E. coli, and for 50% of E. cloacae strains from the gels performed in the buffer with throurea. However, typeability was not improved for Acinetobacter spp. The range of non-typeable species for which thiourea can limit the problem of DNA degradation is considerably wider than described in previous publications.     

1,25-dihydroxycholecalciferol in renal osteodystrophy. Epiphysiolysis--anticonvulsant therapy

Three children with azotaemic renal osteodystrophy were treated with 1,25-dihydroxycholecalciferol (1,25(OH)2D3). All showed clinical, biochemical, and radiological improvement within 6 months of starting treatment. There were no complications. The dose of 1,25(OH)2D3 required was 0-5 microgram per day for 2 children aged 22 and 30 months, and 2 microgram per day for a 15-year-old boy. 2 of the patients were receiving phenobarbitone and phenytoin and in one of them prior treatment with dihydrotachysterol 0-5 mg daily and 6 microgram 1alpha-hydroxycholecalciferol (1alphaOHD3) daily had failed to induce improvement. In one patient, in whom serial iliac bone samples were available, 2 microgram 1,25(OH)2D3 resulted in histological improvement in previously severe osteomalacia. 1,25(OH)2D3 appears to be an effective and safe drug in the treatment of uraemic osteodystrophy.     

新缩瞳剂包公藤甲素人工合成研究

包公藤甲素是从包公藤(Erycibe obtusifolia Benth.)茎中提得的一个新莨菪烷生物碱,具有强烈的缩瞳作用,临床用于治疗青光眼。本文报道用合成的6β-乙酰氧基托品酮为原料,经卤代、水解、还原和N-去甲基化等反应合成包甲素(8)。经光谱测定证实8与天然包甲素的结构完全一致。合成品系外消旋体,其作用机理与天然品相同,而强度则减半。     

4p16.3 haplotype modifying age at onset of Huntington disease

Huntington disease (HD) is caused by an expanded CAG repeat sequence in the HD gene. Although the age at onset is correlated to the CAG repeat length, this correlation only explains approximately half of the variation in onset age. Less variation between siblings indicates that the variation is, in part, explained by genetic modifiers. We analyzed polymorphic loci within or close to the HD gene on the HD chromosome in Danish HD patients. We found one specific haplotype segregating with later age at onset, compared with patients with similar CAG repeat length and another haplotype. The nine Danish families in the study carrying this haplotype most likely have a common founder. Several of the polymorphic loci displayed alleles that may be specific to the late-onset haplotype, implicating that from this study we cannot determine which of the loci tested (or other polymorphic loci in this chromosomal area) do in fact contain genetic modifiers of age at onset.