Langmuir films from antibodies based on amphiphilic polyelectrolytes

A technique for forming Langmuir films from antibodies based on an amphiphilic polyelectrolyte was developed. The physicochemical and immunochemical properties of the Langmuir films obtained were studied. The interaction of HBsAg with the films was found to be described by a model with one binding site, whereas that of HBsAg with antibodies adsorbed on a polystyrene plate, by a model with a positive cooperativity. The use of the novel Langmuir films from antibodies increases the sensitivity of the immunoenzyme assay.     

Factors influencing the selection of analgesia in spontaneously labouring nulliparous women at term

It is the purpose of this study to compare the prognostic value of the Herring classification (lateral pillar) with that of the Catterall classification. The material is constituted by 45 patients affected with Perthes' disease and reviewed an average of 24 years after onset. At follow-up the hips were divided into three classes based on joint congruency as suggested by Stulberg. The Catterall classification demonstrated overall a better predictive value for the Herring system. Instead, the most satisfactory reproducibility seems to be that of Herring: 80% as compared to 42% for the Catterall classification.     

TNF-alpha-induced corticosterone elevation but not serum protein or corticosteroid binding globulin reduction is vagally mediated

OBJECTIVE: Growth deficiency is commonly seen in polytransfused beta-thalassaemia patients, especially in adolescence. It is not completely dependent on the lack of their pubertal growth spurt. GH impairment at different levels (hypothalamic or pituitary) and/or a reduced IGF-1 synthesis have been suggested the main causes of stunted growth in these patients. We evaluated the relationship between GH reserve and growth in short beta-thalassaemia patients. PATIENTS: Twenty-nine short patients (height < -1.8 SDS for chronological age) were divided into two groups (low and normal responders) on the basis of their GH peak during insulin and clonidine tests (< or = and > 20 mU/l, respectively). All but one low responders underwent the GHRH test to exclude the impairment of somatotroph function and in eight of them an IGF-1 generation test was also performed. The two groups were compared with each other with respect to growth (height deficiency, height velocity, bone age and bone delay), haematological characteristics (serum ferritin levels, age at the start both of low (subcutaneous) s.c. infusion of desferrioxamine and of transfusional therapy) and serum IGF-1 and IGF-1 binding protein 3 levels. RESULTS: Thirteen patients (45%) (11 males, two females) were low responders, all but two having serum IGF-1 < 5th centile (< 0.1 centile in 42%); the GHRH test excluded the impairment of somatotroph function in 8/12. Height deficiency, serum ferritin levels, and age at the start of s.c. chelating therapy did not differ in low compared to normal responders. Height was negatively correlated both with the age at the start of s.c. chelating therapy and with serum ferritin levels. CONCLUSION: The reduction of GH reserve, more frequently due to a hypothalamic than to a pituitary dysfunction, is frequent in polytransfused beta-thalassaemia patients, especially in males. The height function is not related to the GH reserve, given the current methods for testing GH reserve. Late start of s.c. chelating therapy as well as haemosiderosis seem to play a role in the height deficiency, but not in GH reserve. Impairment of GH secretory reserve, therefore, cannot be considered the main cause of height deficiency in these patients.     

The practice of health education in acute care settings in Hong Kong: an exploratory study of the contribution of registered nurses

A multiple case study design was used to explore the practice of health education in acute care settings in Hong Kong. Two case studies, a medical ward and a surgical ward, were selected to reflect the real setting in which nurses carry out health education in acute care. Data collection methods involved the use of non-participant observation and semi-structured interviews. Seven nurses and eight patients were interviewed to explore their understanding of health education concepts, the use made in the wards of health education and the factors influencing such practice in the acute settings. Individual and cross-case analysis showed that respondents' understanding of the concept of health education was limited to patient information-giving. Although the importance of health education in acute patient care was acknowledged, the degree to which health education featured in nurses' practice was minimal. Many available opportunities for health education were missed and factors such as nurses' busy-ness and the associated lack of time and staff were identified as influencing health education practice in these acute care settings. Implications for practice and future studies were discussed in the light of these findings.     

Disposable contact lenses and their complications

Disposable soft contact lenses (DSCLs) have been marketed as a safer alternative to conventional soft lenses. Extended-wear DSCLs are designed for one or two weeks of continuous use before disposal. Those for daily wear are designed for use as conventional daily wear soft lenses, with daily removal and storage for 2 to 4 weeks before disposal. Beside minor complications, such as corneal abrasion, giant papillary conjunctivitis and toxic epithelial reactions to contact lens solutions, the most serious complication occurring in contact lens users is ulcerative keratitis. Several case-control studies performed over the last years, demonstrated that disposable contact lenses were associated with a 14-fold excess risk of ulcerative keratitis compared with that for patients wearing conventional daily-wear soft contact lenses and a 13-fold excess risk compared with that for wearers of rigid gas permeable contact lenses. However, the major risk factor for corneal ulceration in contact lens wearers is overnight lens wear of 1 to 3 nights. It was estimated that 49 to 74% of cases of contact lens associated ulcerative keratitis could be prevented by eliminating overnight wear.     

Homologous down-regulation of growth hormone-releasing hormone receptor messenger ribonucleic acid levels

Repeated stimulation of pituitary cell cultures with GH-releasing hormone (GHRH) results in diminished responsiveness, a phenomenon referred to as homologous desensitization. One component of GHRH-induced desensitization is a reduction in GHRH-binding sites, which is reflected by the decreased ability of GHRH to stimulate a rise in intracellular cAMP. In the present study, we sought to determine if homologous down-regulation of GHRH receptor number is due to a decrease in GHRH receptor synthesis. To this end, we developed and validated a quantitative RT-PCR assay system that was capable of assessing differences in GHRH-R messenger RNA (mRNA) levels in total RNA samples obtained from rat pituitary cell cultures. Treatment of pituitary cells with GHRH, for as little as 4 h, resulted in a dose-dependent decrease in GHRH-R mRNA levels. The maximum effect was observed with 0.1 and 1 nM GHRH, which reduced GHRH-R mRNA levels to 49 +/- 4% (mean +/- SEM) and 54 +/- 11% of control values, respectively (n = three separate experiments; P < 0.05). Accompanying the decline in GHRH-R mRNA levels was a rise in GH release; reaching 320 +/- 31% of control values (P < 0.01). Because of the possibility that the rise in medium GH level is the primary regulator of GHRH-R mRNA, we pretreated pituitary cultures for 4 h with GH to achieve a concentration comparable with that induced by a maximal stimulation with GHRH (8 micrograms GH/ml medium). Following pretreatment, cultures were stimulated for 15 min with GHRH and intracellular cAMP accumulation was measured by RIA. GH pretreatment did not impair the ability of GHRH to induce a rise in cAMP concentrations. However, as anticipated, GHRH pretreatment (10 nM) significantly reduced subsequent GHRH-stimulated cAMP to 46% of untreated controls. These data suggest that GHRH, but not GH, directly reduces GHRH-R mRNA levels. To determine whether this effect was mediated through cAMP, cultures were treated with forskolin, a direct stimulator of adenylate cyclase. Forskolin (10 microM) significantly reduced GHRH-R mRNA concentrations (37 +/- 6% of control values) indicating that GHRH acts through the cAMP-second messenger system cascade to regulate GHRH-R mRNA. The somatostatin analogue, octreotide (10 nM), which has been previously reported to decrease adenylate cyclase activity, did not affect GHRH-R mRNA levels. Taken together, these results indicate that GHRH inhibits the production of its own receptor by a receptor-mediated, cAMP-dependent reduction of GHRH-R mRNA accumulation.     

Pharmacological evaluation of iodo and nitro analogs of delta 8-THC and delta 9-THC

One aspect of cannabinoid structure-activity relationships (SARs) that has not been thoroughly investigated is the aromatic (A) ring. Although halogenation of the side chain enhances potency, our recent observation that iodination of the A ring also enhanced activity was surprising. The purpose of this investigation was to establish the steric and electrostatic requirements at these sites of the cannabinoid molecule via molecular modeling, while determining pharmacological activity. Molecular modeling was performed using the Tripos molecular mechanics force field and the semiempirical quantum mechanical package AM1. The Ki values for novel cannabinoids were determined in a [3H]CP-55,940 binding assay and ED50 values generated from four different evaluations in a mouse model. The present studies underscore the increase in potency produced by a dimethylheptyl (DMH) side chain. Trifluoro substitutions on the pentyl side chain, or bromination of the DMH side chain, had little effect on the pharmacological activity. Any substitution at the C4 position of the aryl ring resulted in a loss of activity, which appears to be due to steric hindrances. Nitro, but not iodo, substitution at the C2 position essentially produces an inactive analog, and the drastic alteration of the electrostatic potential appears to be responsible. The altered pharmacological profile of the 2-iodo analog seems to be related to an alteration in the highest occupied molecular orbital because there is no alteration in the electron density map compared to delta 8-tetrahydrocannibinol.     

The influence of medium formulation on phosphomonoester and UDP-hexose levels in cultured human colon tumor cells as observed by 31P NMR spectroscopy

High-resolution 31P NMR spectroscopy at 11.7 T was used to examine the influence of medium formulation (medium and serum type, and concentrations of glucose and inositol) on the cellular phosphate metabolism of CX-1 cells, a human colon cancer cell line derived from HT-29 cells. Striking differences in the 31P spectra of harvested CX-1 cells were observed. The largest variation was seen in the phosphocholine and UDP-hexose levels (up to seven-fold changes), with smaller differences in the levels of other phosphate metabolites. The major UDP-hexose species were found to be UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine (ca 2:1 ratio), which have been proposed in the literature to be markers of cell differentiation status. Medium-induced alterations in metabolite levels were much greater than the normal variations seen in CX-1 control samples grown under identical conditions. They even exceeded the characteristic differences observed between different human tumor cell lines grown under one set of culture conditions. The remarkable sensitivity of CX-1 cellular phosphate metabolism to the culture environment has implications for the comparison of in vitro vs in vivo spectra, and for the interpretation of effects due to growth and therapy.     

Localised neuronal migration disorder and intractable epilepsy: a prenatal vascular aetiology

Localised neuronal heterotopias are an increasingly recognised cause of intractable focal epilepsies. The aetiology of these circumscribed disorders of neuronal migration is often unknown although in some instances proximity to areas of prenatal infarction suggests that severe ischaemia was responsible. A patient is described with intractable complex partial seizures associated with heterotopic grey matter and cerebral hypoplasia confined to the territory of the left posterior cerebral artery; the left hippocampus was spared. Angiography showed a normal left anterior choroidal artery but a hypoplastic left posterior cerebral artery, implicating prenatal ischaemia without frank infarction as the aetiology of the malformation.     

Pain characteristics and their management in persons with AIDS

Discussion of pain problems in persons with AIDS has been limited in medical and nursing literature, yet pain is a major source of suffering and concern for patients. Common pain characteristics are described in 100 persons with CDC-defined AIDS, using the 1987 definition. The two most frequently cited types of pain for both drugs users and nondrug users with AIDS were abdominal pain and neuropathic pain. Drug users experienced pain due to esophagitis and headaches more frequently than nondrug users, while nondrug users experienced Kaposi's sarcoma-related pain more often. Treatment responses were individualized, with drug users requiring more frequent use of opiates. General treatment strategies are suggested with special emphasis on the unique needs of PWAs.