Temporal changes in glial fibrillary acidic protein messenger RNA and [3H]PK11195 binding in relation to imidazoline-I2-receptor and alpha 2-adrenoceptor binding in the hippocampus following transient global forebrain ischaemia in the rat

Immunohistochemical studies have demonstrated that following global forebrain ischaemia the selective neuronal loss that occurs in the CA1 pyramidal cell layer of the hippocampus is accompanied by a reactive astrocytosis, characterized by increases in glial fibrillary acidic protein, and activation of microglia. In this study the spatial changes in glial fibrillary acidic protein messenger RNA levels in the hippocampus have been mapped four, eight, 12, 16 and 20 days following 10 min of global forebrain ischaemia in the rat and related to changes in [3H]PK11195 binding to peripheral benzodiazepine receptors, a putative marker of activated microglia. Recent studies have suggested that the imidazoline-I2-receptor, one of a class of non-adrenergic receptors related to, but structurally and functionally distinct from alpha 2-adrenoceptors, may have a functional role in controlling the expression of glial fibrillary acidic protein. To explore this possibility further we have also mapped changes in imidazoline-I2-receptor and alpha 2-adrenoceptor binding sites. Following transient ischaemia there was a marked, biphasic increase in glial fibrillary acidic protein messenger RNA levels throughout the vulnerable CA1 region of the hippocampus, peaking four days after ischaemia and then increasing gradually during the remainder of the study period. There was also a sustained increase in [3H]PK11195 binding, however, in contrast to the initial increase in glial fibrillary acidic protein messenger RNA levels that peaked four days after ischaemia the density of [3H]PK11195 binding increased rapidly in all strata of the CA1 region over the first eight days and then increased more slowly throughout days 12 to 20. Despite the marked increase in glial fibrillary acidic protein messenger RNA levels there was no concomitant alteration in imidazoline-I2-receptor binding sites detected using the specific radioligand, [3H]2-(2-benzofuranyl)-2-imidazoline, although alpha 2-adrenoceptor binding was decreased at eight days after ischaemia and did not recover. The time-course and biphasic nature of the changes in the astrocytic marker, glial fibrillary acidic protein messenger RNA, in the hippocampus following ischaemia may reflect different functions of glial fibrillary acidic protein-reactive astrocytes in the post-ischaemic period. Differences in temporal expression of glial fibrillary acidic protein messenger RNA and [3H]PK11195 binding support the proposed localization of peripheral benzodiazepine receptors on activated microglia, as distinct from reactive astrocytes. There was no evidence in the present study that imidazoline-I2-receptors are functionally linked to glial fibrillary acidic protein expression as the reactive astrocytosis in the hippocampus following ischaemia was not associated with changes in imidazoline-I2-receptor binding site density.     

Indications for the surgical repair of unilateral aural atresia in children

OBJECTIVE: This study aimed to clarify the indications for elective surgical repair of unilateral aural atresia in children and to review the rates of successful repair in the literature. DATA SOURCES: A search of the published English language literature, 1966-1997, was conducted using the key words aural atresia. STUDY SELECTION: Articles were selected on the basis of their inclusion of the authors' indications for surgical repair of aural atresia or the inclusion of surgical series that showed outcomes. DATA EXTRACTION: Articles reviewed in the review had to either provide specific guidelines for surgical repair of unilateral aural atresia or provide postoperative pure-tone averages, air-bone gaps, or speech reception thresholds. DATA SYNTHESIS: The authors compiled the relevant data into summary tables and extracted conclusions from these data. CONCLUSIONS: Elective surgical repair of unilateral aural atresia should only be attempted in children who meet specific anatomic criteria that predict that they are the most likely to benefit from the results of surgery. Otherwise, repair should be delayed until the age at which the patient can make an informed decision, knowing the risks, benefits, and consequences of this difficult surgery. Parents and surgeons must have a realistic expectation of the surgical results and the practiced benefit to be expected with a normal, contralateral ear.     

Vesiculobullous Hailey-Hailey disease: successful treatment with oral retinoids

A 56-year-old male presented with a pruritic, generalized vesiculobullous eruption. His past history revealed classical symptoms of limited Hailey-Hailey disease for 34 years. Clinically, vesicles, bullae and occasional pustules were present and multiple biopsies confirmed this to be an unusual presentation of Hailey-Hailey disease. Various therapeutic modalities including topical and oral antibiotics, oral prednisone and dapsone failed to achieve sustained remission. Treatment with low-dose oral etretinate (25 mg daily) produced marked clinical improvement with complete suppression of new vesicle formation after 6 weeks.     

Arylidene polymers XIX: Synthesis and properties of aromatic polyphosphate from diarylidenecycloalkanones

Polyphosphate esters were synthesized by interfacial polymerization of 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzylidene)cyclohexanone, 2,6-divanillylidenecyclohexanone or 2,7-bis(p-hydroxybenzylidene)cycloheptanone with phenyl phosphorodichloridate. The resulting polymers were characterized by elemental analysis, IR spectroscopy, solubility and viscometry measurements. The thermal properties of the polymers were evaluated by TGA measurements and correlated with their structural units. The crystallinity of all the polyphosphate esters was tested by X-ray analysis.     

Studies of the denaturation patterns of bovine alpha-crystallin using an ionic denaturant, guanidine hydrochloride and a non-ionic denaturant, urea

The effects of non-ionic and ionic denaturation and denaturation/renaturation on the native structure of alpha-crystallin at room temperature were examined. Native alpha-crystallin, at concentrations above and below the previously reported critical micelle concentration (CMC) range, was denatured by varying concentrations of urea and guanidine hydrochloride. The resulting denatured samples were examined by gel filtration fast performance liquid chromatography (FPLC), circular dichroism spectropolarimetry (CD), and transmission electron microscopy. Elution peak samples from gel filtration chromatography with sufficiently high concentrations were examined for subunit composition by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The studies presented herein demonstrate that the denaturation and renaturation of alpha-crystallin via non-ionic urea denaturation results in different renaturation species, depending upon the initial concentration of alpha-crystallin which is denatured and the concentration of urea, including certain species which, by gel filtration FPLC, have an apparent molecular weight greater than the native 800 kD aggregate. Transmission electron microscopy has also demonstrated the existence of a high molecular weight aggregate form for denatured samples. Ionic dissociation, in contrast, proceeds much in the same manner above and below the CMC range, the major difference occurring at 2 M guanidine hydrochloride. alpha B-crystallin is preferentially removed from the native alpha-crystallin aggregate upon treatment with 2 M guanidine hydrochloride indicating, once again, differences between the two subunits. Above and below the CMC range, dissociation with guanidine hydrochloride appears to plateau after 4 M guanidine hydrochloride as indicated by the presence of two apparent homotetrameric species and no further dissociation of these species with increasing guanidine hydrochloride concentrations. CD demonstrates that some secondary structure, which is lost with lower concentrations of alpha-crystallin, is still present when concentrations of alpha-crystallin, well above the critical micelle concentration range, are treated with high concentrations of urea at room temperature. In contrast, concentrations both above and below the CMC range demonstrate a significant loss of secondary structure upon treatment with 2 M guanidine hydrochloride. Finally, ionic denaturation and subsequent renaturation results in the formation of a species which is functionally incapable of protecting gamma-crystallin from heat-induced aggregation.     

Saccharide-assisted delivery of cytotoxic liposomes to human malignant cells

The overexpression of lectins by malignant cells was applied for in vitro targeting of liposomes equipped with a saccharide vector and loaded in the lipid phase with a lipid derivative of anticancer agent sarcolysine. The lectin specificity of human leukemia HL-60 and human lung adenocarcinoma ACL cells was revealed by tests with fluorescein-labeled sugar probes. With the help of fluorescent lipid dye it was shown that active saccharide ligands increased the level of the vectored liposome binding to malignant cells by 50-80% as compared to liposomes without vector or with inactive one. The degree of liposome/cell membrane fusion was monitored fluorometrically and was shown to be complete and independent of the vectors. The targeted drug-loaded liposomes had the cytotoxic activity 2-4 times higher as compared to the vector-free ones.     

Changes in dental caries prevalence of school children in Araraquara, SP, Brazil

Previous reports indicate that venous thrombosis is an infrequent problem in patients with HIV infection. Despite this, various HIV-related factors have been proposed as potentially thrombogenic and an HIV-related hypercoagulability has been suggested. At the present time, there exists no consensus of opinion regarding prophylaxis against venous thrombosis for hospitalized patients with HIV. This article aims to provide an overview of venous thrombosis in HIV infection with particular reference to published and personal evidence for possible risk factors and their implications for prophylaxis.     

Conservative management of penetrating and blunt Type III renal injuries

This study examines whether, while controlling for local economic conditions, job design and other organizational factors affect facility aide turnover rates in a sample of 250 nursing homes from 10 states. Facility characteristics were largely based on administrator and director of nursing interviews conducted in 1993 as part of the Health Care Financing Administration's evaluation of the Resident Assessment Instrument (RAI) implementation. Aide turnover was significantly reduced by involvement in interdisciplinary care plan meetings. Turnover rates were higher in for-profit homes. Aide involvement in assessments, aide training and workload, case mix severity, payor source mix, and facility size were not significantly related to aide turnover.