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Biomedical subjects

B Smith

Publications and source records attributed to B Smith.

At least 19 recordsLinked to original sources
PubMed1992

Transglutaminase catalyses the modification of glutamine side chains in the C-terminal region of bovine beta-lactoglobulin.

The transglutaminase-catalysed incorporation of primary amines (putrescine and monodansylcadaverine) into bovine beta-lactoglobulin has been studied. In the presence of 1 mM-dithiothreitol between 1 and 2 mol of amine can be incorporated per mol of beta-lactoglobulin subunit. There is very little incorporation of amines in the absence of reducing agent. By isolating and sequencing the modified peptides, the sites of modification have been identified as Gln-159 (preferred) and Gln-155. C.d. has been used to study the structure of beta-lactoglobulin over a range of pH values and in the presence or absence of dithiothreitol. The results are discussed in terms of the X-ray-crystallographically determined structure of beta-lactoglobulin.

Amino Acid Sequence↗
PubMed1992

Simultaneous separation and purification of mononuclear and polymorphonuclear cells from the peripheral blood of cats.

Peripheral blood mononuclear cells (PBMC) and polymorphonuclear cells (PMNC) play important roles in immunodeficiency diseases and AIDS-like syndromes in cats caused by feline leukemia virus (FeLV) and presumably also when caused by feline immunodeficiency virus (FIV). For comparative or functional studies it is advantageous or necessary to obtain these cells as separate entities from the same sample of an animal. Therefore, we analyzed the technical parameters of obtaining, separating and purifying these cells simultaneously from several blood samples of several cats. Flow cytometric studies with outbred cats indicated that of various cell separation/purification methods, e.g. from lysed whole blood, by Histopaque 1.077 or 1.119 single-density, or by 1.077/1.119 double-density centrifugation, the 1.077/1.119 double-density centrifugation of diluted whole blood is the most consistent, practical and effective method of yielding both highly purified PBMC and PMNC as separate entities from the same sample. The interface between plasma and 1.077 contained an average 86% PBMC vs. 14% PMNC, and the interface between 1.077 and 1.119 an average of 2% PBMC vs. 98% PMNC. Lymphocytes separated by this method had an average CD4/CD8 T-cell ratio of 2.0. These data indicate that Histopaque 1.077/1.119 double-density gradient allows purification and physical separation of lymphocytes and phagocytes from a blood sample, enabling the investigator to examine both cell types from the same sample simultaneously.

Animals↗
PubMed1992

Severe contractures of the proximal interphalangeal joint in Dupuytren's disease: results of a prospective trial of operative correction and dynamic extension splinting.

In a prospective study, 23 proximal interphalangeal joints that were severely contracted (> or = 45 degrees) as a result of Dupuytren's disease underwent operative correction and 6 months of dynamic extension splinting. Proximal interphalangeal joint extension was measured preoperatively and postoperatively at 3-month intervals for 1 year and at 6-month intervals thereafter. Mean follow-up was 2 years (minimum, 1 year). Overall, at 2 years, 44% improvement in proximal interphalangeal joint extension was noted. Mean improvement of 59% in proximal interphalangeal joint extension was noted in patients who complied with the postoperative dynamic extension splinting program. Patients who were noncomplaint demonstrated a 25% improvement in proximal interphalangeal joint extension. The difference in values between patients who were compliant and those who were not was statistically significant. Other factors--severity of contracture, digit involved, and the necessity for capsular release--were not significantly related to outcome. This study suggests that soft tissue responds to continuous dynamic extension stresses and can be remodeled over time.

Adult↗
PubMed1992

Peripheral myelin protein-22 gene maps in the duplication in chromosome 17p11.2 associated with Charcot-Marie-Tooth 1A.

Charcot-Marie-Tooth disease 1A (CMT1A) is a hereditary demyelinating peripheral neuropathy, associated with a DNA duplication on chromosome 17p11.2. A related disorder in the mouse, trembler (Tr), maps to mouse chromosome 11 which has syntenic homology to human chromosome 17p. Recently, the peripheral myelin protein-22 (pmp-22) gene was identified as the likely Tr locus. We have constructed a partial yeast artificial chromosome contig spanning the CMT1A gene region and mapped the PMP-22 gene to the duplicated region. These observations further implicate PMP-22 as a candidate gene for CMT1A, and suggest that over-expression of this gene may be one mechanism that produces the CMT1A phenotype.

Animals↗
PubMed1992

Maternal depression, assessment methods, and physical symptoms affect estimates of depressive symptomatology among children with cancer.

Investigated the incidence of depressive symptoms and their covariates in a sample of 99 children undergoing treatment for cancer and their mothers. Although the prevalence of depressive symptoms falling within the clinical range was low (7 to 8%), classification of these children was highly dependent upon the informant and instrument used. Interrater reliabilities did not differ from chance levels. Separate multiple regression analyses of the mother's and nurse's ratings of the child's level of depression, the child's self-report on the Child Depression Inventory, and the mother's responses to the Child Behavior Checklist depression scales revealed different statistical models for each method of assessment. However, increased severity of the mother's self-report of depressive symptoms on the Beck Depression Inventory, which was predicted by low perceived social support and hospitalization of her child, was associated with higher levels of child depression on all child- and parent-report measures. Parental adjustment, sociodemographic, and medical factors as well as methods of assessment must be addressed by models explaining the etiology of depressive symptoms among pediatric oncology patients.

Adult↗
PubMed1992

Characterization of a glucocorticosteroid-induced inhibitor of interferon-gamma induction of HLA-DR expression.

Interferon gamma (IFN-gamma) induces human leukocyte antigen (HLA)-DR antigen expression on a variety of cell types, and in human skin cells this induction is inhibited by trypsin inhibitors. Recently a trypsin-like protease was characterized whose activity is required for HLA-DR induction in a hybrid epidermal cell line. Glucocorticosteroids also inhibit IFN-gamma-induced HLA-DR expression, and similarities have been noted between the inhibition by trypsin inhibitors and by glucocorticosteroids. To assess the possibility that glucocorticosteroid inhibition of IFN-gamma-induced HLA-DR expression might be due to induction of an inhibitor of trypsin activity that is re-expression, we examined culture medium supernates (CM) of glucocorticosteroid-treated cells for HLA-DR- and trypsin-inhibitory activities. We report here that CM of glucocorticosteroid-treated H12 cells contain inhibitors of HLA-DR expression and of trypsin activity, but that the two inhibitors are not identical. H12 cells constitutively secrete a greater than 30,000 MW, acid- and heat-stable trypsin inhibitor, whose expression is not modulated by glucocorticosteroid or IFN-gamma, and that does not inhibit IFN-gamma-induced HLA-DR expression. The HLA-DR inhibitor, on the other hand, is present only in CM of glucocorticosteroid-treated cells, is distinct from glucocorticosteroid itself, of a MW less than 500 and does not inhibit trypsin. We conclude, therefore, that the glucocorticosteroid inhibition of IFN-gamma-induced HLA-DR expression is by a mechanism other than secretion of a trypsin inhibitor.

Cells, Cultured↗
PubMed1992

Attainments of severely mentally retarded adolescents by aetiology.

Piagetian cognitive level, language abilities, adaptive behaviour and graphic skills were assessed in three groups of adolescents with severe learning difficulties: Down's syndrome (DS), congenital cerebral palsy (CP) and unknown origin (NSP). Results were compared with assessments made seven years earlier. A wide range of scores was observed in each group. Medians of the DS and NSP groups were similar and generally were significantly higher than those of the CP group. When the number and severity of other impairments and disabilities (HDCP) was taken into account, group averages of attainments and progress were very similar. Implications for intervention are discussed.

Achievement↗
PubMed1992

Analysis of the DNA duplication 17p11.2 in Charcot-Marie-Tooth neuropathy type 1 pedigrees: additional evidence for a third autosomal CMT1 locus.

We have restudied two clinically typical Charcot-Marie-Tooth neuropathy type 1 (CMT1; also known as hereditary motor and sensory neuropathy 1) pedigrees that were previously reported to be unlinked to the regions of proximal chromosome 1q and chromosome 17p by multipoint linkage analyses. In these two pedigrees, there is no evidence for linkage to additional DNA markers that flank and span the CMT1A locus on chromosome 17p11.2, and a duplication associated with CMT1A is not present in these pedigrees. These findings confirm that the CMT1 locus in these two pedigrees does not map to chromosome 17p11.2 or 1q, and provide further evidence for the existence of a third autosomal locus for CMT1.

Charcot-Marie-Tooth Disease↗
PubMed1992

Intraforaminal repair of plexus spinal nerves by a posterior approach: an experimental study.

Many spinal nerve roots injured due to stretch or other types of lesions are not reparable. Some spinal nerves might be repaired if they could be exposed in their intraforaminal course. A posterior subscapular approach for a more lateral exposure of the brachial plexus was combined with a facetectomy to expose intraforaminal nerves in a series of Macaca rhesus monkeys. This approach exposed a 6- to 10-mm segment of spinal nerve not approachable by a more classic anterior operation. Sural grafts were placed from the dural exit of the spinal nerves to the cord level of the plexus. Nine surviving animals were followed for 36 to 54 months and observed for clinical evidence of return of function. In each animal at least one electromyogram (EMG) was performed. The plexus was then re-exposed and intraoperative nerve action potentials were recorded across graft sites. Evoked muscle action potential and cortical potentials were recorded in six animals. Despite the proximal level of repair, adequate regeneration was shown by clinical, electrical, and histological studies. Functional return was best to the supraspinatus and biceps muscles and to wrist and finger flexors. Clinical recovery was present, but less effective, for deltoid, wrist, and finger extensors and intrinsic muscles of the hand, despite evidence on EMG of reinnervation. Recovery of the infraspinatus muscle was poor. Nerve action potentials could be recorded across each graft site. Reinnervational activity was recorded by EMG and evoked muscle action potential studies in most of the muscles studied, despite the persistence of some denervational changes 3 years or more after injury and repair. Histological studies confirmed the presence of a large number of axons of moderate size and myelination even at the forearm level.

Action Potentials↗
PubMed1992

CAPD disconnect systems: UK peritonitis experience.

We reviewed peritonitis (P) experience of four UK units using single use Y (Freeline T.M., Baxter UK)(F) and Twinbag (Solo T.M., Baxter UK) (S) disconnect systems, which incorporate the 'Flush Before Fill' principle. We aim to show clinical achievements, in varying circumstances, in the light of previously published in vitro study results. Each unit recorded P data, i.e., rates, causative organisms, and recurrences (R) over a 12 month period (Sept 89-Aug 90). This data was then analysed by system, by unit and in total. Each unit had similar definitions for P and R, but had varying system selection criteria. Unit 1 had a fairly open criteria for F use, then became more selective at the same time as introducing S. In unit 2, F, and then S, were first choice systems for all (inc. blind diabetics). Unit 3 trains every pt. on non-disconnect System 2, then pt. choice determines if they are retained onto a disconnect system. Unit 4 had a more highly selected population. Results, expressed as episodes/patient month, were as follows: [table: see text] We conclude that it is possible to achieve a low incidence of P, especially that caused by S. epidermidis, particularly with S. It would seem the extent is related to pt. to system selection criteria. The effects of R and ES/TI need to be addressed.

Humans↗
PubMed1992

Oral ketamine premedication to alleviate the distress of invasive procedures in pediatric oncology patients.

This study prospectively evaluated the efficacy of oral ketamine in alleviating procedure-related distress in pediatric oncology patients. Ketamine (10 mg/kg) was administered orally to 35 children and adolescents, ranging in age from 14 months to 17 years (mean = 6.5 years). Procedure-related distress was evaluated by using parent/clinician ratings and the Observational Scale of Behavioral Distress (OSBD-R). Eighty-seven percent of children were sedated within 45 minutes. Clinician and parent ratings were similar, with 77% rating procedural distress as low (0 to 3). The OSBD-R scores were low throughout all phases of the study. Although this study was neither randomized nor placebo-controlled, statistical comparison of the OSBD-R scores of the patients who received oral ketamine with those of historical controls (from a study previously performed at the same institution but using intravenous midazolam) showed significantly less distress (P < .001) during the procedure in children who received oral ketamine. Additionally, OSBD-R scores of the patients who received oral ketamine were significantly lower (P < .001) during all phases than those of the saline placebo group in the other study. No cardiorespiratory side effects related to ketamine were noted. The majority of patients showed recovery from sedation within 2 hours following the procedure. In conclusion, oral ketamine effectively alleviated procedure-related distress in pediatric oncology patients.

Administration, Oral↗
PubMed1991

Detection of melanoma cells in peripheral blood by means of reverse transcriptase and polymerase chain reaction.

Only small numbers of cells from solid tumours are needed for haematogenous metastasis. Detection is difficult because existing techniques are not sensitive enough. We have used reverse transcriptase to make complementary DNA from peripheral blood messenger RNA, and the polymerase chain reaction (PCR) to amplify cDNA specific for a gene actively transcribed only in the tumour tissue type. We prepared cDNA from peripheral blood of seven patients with malignant melanoma, four patients with other metastatic cancers, and four healthy subjects, as well as from several melanoma-derived cell lines. PCR was used to amplify the gene for tyrosinase, a tissue-specific gene in melanocytes. Since normal melanocytes are not thought to circulate in peripheral blood, detection of tyrosinase transcription in peripheral blood should indicate the presence of circulating cancer cells. The method was highly sensitive and could detect a single melanoma cell from a cell line in 2 ml normal blood. Blood samples from four of the seven patients with malignant melanoma gave positive results, whereas all eight control subjects gave negative results. This method does not depend on the characterisation of cancer-specific genetic abnormalities and can be applied to any cancer for which tissue-specific genes can be identified, including epithelial cancers. It could prove useful in the diagnosis of primary or metastatic cancers, in assessing prognosis, and in detecting residual disease after treatment.

Amino Acid Sequence↗
PubMed1991

Biochemical characterization of histamine H1 receptors in bovine adrenal medulla.

Bovine adrenal medullary membranes display high affinity and saturable binding to [3H]mepyramine, a selective H1 antagonist, with Kd of 1.5 +/- 0.1 nM and Bmax of 694 +/- 12 fmol/mg protein. [3H]Azidobenzpyramine, an azidobenzamide derivative of mepyramine, was synthesized and used to photolabel the high affinity mepyramine binding sites. Following photolysis, a protein component with an approximate molecular weight of 53-58 kDa was shown to be covalently labeled, as judged by gel filtration and SDS/PAGE; labeling being greatly reduced in the presence of excess unlabeled mepyramine. These results indicate that bovine adrenal medulla expresses a large number of H1 receptors, which are pharmacologically and biochemically indistinguishable from the H1 receptor of many other tissues of various species.

Adrenal Medulla↗