Search PubMed⌕ Search

Biomedical subjects

D Smith

Publications and source records attributed to D Smith.

At least 757 records · Page 42Linked to original sources
PubMed1991

Purification and characterization of a Coffea canephora alpha-D-galactosidase isozyme.

Exoglycosidases modify carbohydrate epitopes on glycoproteins and glycolipids. The alpha-D-galactosidase from Coffea canephora is an important exoglycosidase which degrades the human blood group B epitope. Although multiple isozymes have been described, they have never been demonstrably purified and thoroughly characterized. We have developed a technique to purify an isozyme to homogeneity. The isolated enzyme has a molecular weight of 36.7 kDa by SDS PAGE and 34.0 kDa by gel filtration. The isozyme is highly selective for alpha-D-galactosides and inactive against other low molecular weight substrates. It hydrolyzes the the terminal alpha-D-galactosyl residue from the blood group B epitope. Protease activity is below detectable limits. The isozyme has a broad pH optima at 6.3, a pl of 7.03, is unaffected by ionic strength, and is stable at 4 degrees C.

Amino Acids↗
PubMed1991

The development of optokinetic nystagmus in strabismic and monocularly enucleated subjects.

Assymmetries of monocular optokinetic nystagmus (OKN) following anomalous visual experience are thought to be due to disruption at the cortical level. Visual disruption usually results from eye suture (in animals), unilateral dense and central cataracts or strabismus (in humans). Many form-deprived animals and humans frequently show a residual strabismus after lid opening (animals) or cataract extraction and optical correction (humans). We wanted to determine whether strabismus was unique in causing monocular asymmetries of OKN. Two independent observers rated eye movement videotapes of 20 normal subjects, the non-deviating eye of 25 unilateral strabismic subjects and 29 unilaterally eye-enucleated subjects, who were watching either a nasally directed square wave grating, a temporally directed square wave grating, or a blank field. Observers rated the proportion of trials where OKN occurred, the duration of OKN in each trial and the number of beats of OKN within each trial. Monocular OKN was symmetrical in normal subjects for the proportion and duration measures, but half the normal group showed small but significant asymmetries for the beats measure. Subjects in both enucleate and strabismic groups showed asymmetries of OKN favouring nasally directed stimulation, but only the early onset strabismics (as a group) showed asymmetries that were significantly greater (P less than 0.05) than the normal group. Asymmetry scores correlated significantly with age of diagnosis of strabismus for the strabismic group but not with age of enucleation for the enucleate group. The results are discussed in terms of binocular competition.

Adolescent↗
PubMed1991

PCR-detected genital papillomavirus infection: prevalence and association with risk factors for cervical cancer.

In an investigation conducted in student health clinic patients, the polymerase chain reaction was used to detect human papillomavirus (HPV) DNA, thereby allowing measurement of the prevalence of HPV infection and study of the association between HPV infection and risk factors for cervical cancer. Of 159 women eligible to participate, 105 (66%) provided a specimen of cervical cells for HPV typing, and also answered an interviewer-administered questionnaire which sought information on risk factors for cervical cancer. Nucleic acid extracted from cervical cells was screened with primers for HPV types 6, 11, 16, 18, 33 and with an HPV Consensus primer. Overall, the prevalence of HPV infection was 18.1%, while for HPV-6/11 it was 2.9% and for HPV-16/18 it was 10.5%. There were statistically significant increases in risk of HPV infection with a history of ever having smoked cigarettes (overall, and for HPV-16 alone) and with a history of usually having sexual intercourse during menstrual periods (overall, but not for HPV-16), and these associations were independent of the effects of age at first sexual intercourse and number of sexual partners. The latter 2 variables, as well as the total number of occasions of sexual intercourse, a history of anal intercourse, and a history of ever having used oral contraceptives, were not associated with statistically significant alterations in risk of HPV infection.

Adult↗
PubMed1991

Apparent Opitz BBBG syndrome with a partial duplication of 5p.

We describe a patient with a paracentric inversion and partial duplication of chromosome 5p. In addition this patient presented with a malformation pattern consistent with Opitz BBBG syndrome. This implies that the gene responsible for this single gene defect may be located within this duplicated region.

Abnormalities, Multiple↗
PubMed1991

Improvement of cyclosporin absorption in children after liver transplantation by means of water-soluble vitamin E.

Many childhood recipients of liver transplantation require massive doses of cyclosporin to achieve therapeutic blood concentrations of the drug. The impaired absorption of this strongly lipophilic drug may be due to reduced intestinal absorptive area, suboptimal mixing of the drug with hepatobiliary secretions, or residual cholestasis. Improvement of cyclosporin absorption was sought by means of oral coadministration of d-alpha-tocopheryl-polyethylene-glycol-1000 succinate (TPGS), a water-soluble form of vitamin E which can form micelles. 25 mg/kg daily of TPGS was given to six paediatric liver transplant recipients and one young adult with severe hepatobiliary graft-vs-host disease after bone-marrow transplantation, who required 29-136 mg/kg cyclosporin daily to achieve therapeutic cyclosporin blood concentrations. Five responded; the oral cyclosporin dose could be reduced by 40-72% within 2 months. In addition, intravenous cyclosporin was stopped in two of the responders. In the two non-responders the cyclosporin doses at entry were similar to those in the responders after TPGS treatment. Oral cyclosporin absorption tests correctly predicted the outcome of treatment in three responders and one non-responder tested. Treatment with TPGS to enhance cyclosporin absorption might be a useful way of reducing the high cost of immunosuppression in paediatric liver transplant recipients.

Adult↗
PubMed1991

Simian varicella virus DNA in dorsal root ganglia.

Clinical, pathological, immunological, and virological evidence suggests that simian varicella virus (SVV) infection of primates is the counterpart of varicella-zoster virus infection of humans. To determine whether these two viruses share similarities in their properties during latency, we analyzed ganglia and brain of an African green monkey experimentally infected with SVV for the presence of viral nucleic acid using the polymerase chain reaction technique. We detected SVV DNA in dorsal root ganglia but not in brain of this monkey, which demonstrated no apparent clinical signs of SVV infection. Our results suggest that SVV becomes latent in monkey ganglia and that latency can develop in the absence of clinical varicella (chickenpox). These studies provide an animal model system to study varicella virus latency.

Animals↗
PubMed1991

Improved speed and accuracy of calculations with a programmable calculator in pediatric emergency scenarios.

Both mathematical and selection errors may occur when ordering drug or fluid therapy in a busy emergency department. In an attempt to improve the speed and accuracy of such calculations, we programmed a hand-held calculator to assist in drug and intravenous fluid therapy dosages and rates for three emergency situations: diabetic ketoacidosis, asthma, and asystole. Performance by 58 subjects at various levels of training was compared when using either the programmable calculator or standard materials and methods. When standard methods were used, an average of 30.6 minutes was needed to complete the three scenarios, with an accuracy of 73%; by contrast, use of programmable calculator resulted in a significant decline in time needed to calculate doses (an average of only 8.5 minutes), with an improved accuracy of 98%. The use of a programmable calculator can result in a significant improvement in both speed and accuracy of drug and fluid selection and dosage and rate calculations, regardless of the level of the subject's medical training.

Age Factors↗
PubMed1991

Study of belching ability in antireflux surgery patients and normal volunteers.

The ability to belch was evaluated by a novel test, after gaseous stomach distension to standard volume, in 16 patients after antireflux surgery and nine healthy volunteers. A structured assessment of dyspeptic symptoms was also carried out in both groups. Repeat studies in volunteers showed acceptable reproducibility for the new test of belching capacity (within-subject coefficient of variance 4.5 per cent). After antireflux surgery, patients had lower volume individual belches (median(range) 27.5(0-104) ml in patients versus 76(15-165) ml in volunteers; P less than 0.02) and belched less gas within 1 h of the stimulus than volunteers (median(range) 205(0-1363) ml in patients versus 456(45-818) ml in volunteers; P less than 0.05). Belching frequency was similar in both groups. The incidence and severity of symptoms were unrelated to belched gas volumes.

Adult↗
PubMed1991

Mucosal function after ileal mucosal fenestration and colonic autotransplantation.

A method of small bowel mucosal augmentation called ileal mucosal fenestration and colonic autotransplantation (IMFCA) was devised and tested in pigs. In this technique, a vascularized mucosal graft was harvested from a 12-cm ileal loop, fenestrated by serial incision and then expanded to 20 cm. A 20-cm colonic loop was isolated and surgical mucosectomy was carried out. The fenestrated ileal mucosal graft was then autotransplanted into the prepared colon and the resulting composite structure was exteriorized as a Thiry-Vella loop. With this technique, ileal mucosal fenestrations healed by lateral epithelial in-growth, giving a new mucosal continuum within the recipient colon. At 60 days after surgery, the surface area of transplanted mucosa exceeded that within the original ileal loop by approximately 85 per cent. At this time, the transplanted mucosa had morphology and capacity for Na(+)-dependent glucose transport which were indistinguishable from those of control ileal mucosa.

Animals↗
PubMed1991

Changes in beta-adrenergic receptor distribution on immunocytes during differentiation: an analysis of T cells and macrophages.

The ability of cells of the immune system, immunocytes, to receive signals from the nervous as well as the endocrine system is dependent on the cells' expression of receptors for neurotransmitters and neurohormones. The number of receptors, especially beta adrenergic receptors (BARs), varies with the functional subset of immunocytes. However, little is known about how receptor number may vary during the life span (stem cell to mature activated immunocyte) of a given cell type. In this study, we have addressed this question by examining the affinities (Kd's) and the changes in receptor number (Bmax) on (1) clones of T cells and macrophages, (2) fresh thymocytes and splenocytes before and after activation with Concanavalin A (Con A) and phorbol myristate acetate (PMA)/Ca2+ ionophore (A23187), and (3) the cloned human monocyte U937 and the murine thymic lymphoma cell BW5147, in the presence and absence of PMA and A23187 ionophore. Drug treatments of fresh and cloned immunocytes alter the number but not the affinity of beta-receptors. Con A increases the number of beta-adrenergic receptors per cell, whereas PMA/ionophore decreases it. Similar decreases in BAR number are induced by PMA on cell lines BW5147 and U937. These data indicate that changes in receptor number can be regulated with different states of cell maturation and function. Thus, the immunological status of a given cell can influence the expression of BARs, thereby modulating its ability to respond to signals from the nervous and endocrine systems.

Animals↗
PubMed1991

Computerised method for acquisition and display of gastrointestinal motility data.

A computerised system is developed for the acquisition and display of gastrointestinal motility data which utilises a purpose developed software program called 'PC-motil', running on an IBM compatible microcomputer. 'PC-motil' displays data during collection, writes data to disk file and compresses all data at the end of a study on to a single monitor screen for convenient overview. Any area of interest, in single or multiple channels, may be selected and expanded for detailed examination. This system is tested by the recording of gastric and jejunal motility patterns of 11 healthy volunteers in fasting and fed states. All antral and jejunal migrating motor complexes (MMCs) in fasting studies, as well as all fed motility patterns were recognisable in both 'compressed' and 'expanded' form. The reproduction of motility patterns by the computer based system was indistinguishable from that of a conventional analogue chart recorder. This computerised system provides a convenient and cost-effective means of acquisition, storage and display of motility data in digital form.

Adult↗
PubMed1991

Adverse psychologic consequences of positive cytologic cervical screening.

Cervical cancer is still widely prevalent in the female population. This study explores the relationship of cervical cancer screening, positive versus negative Papanicolaou's test results, and psychologic status among lower-income minority women. All patients were interviewed 3 months after they had received initial test results. One hundred six women with normal Papanicolaou's test results were compared with 118 women who were referred for colposcopic examination for follow-up of positive test results. Women with positive Papanicolaou's-test results showed statistically significant elevations in worries about cancer and impairments in mood, daily activities, sexual interest, and sleep patterns. More fine-grained analyses revealed that the effects of positive results were most pronounced among those women who did not comply with colposcopy (n = 53). These findings suggest that lack of compliance with follow-up may maintain high levels of uncertainty about disease and may interfere with successful psychologic adaptation. Health education targeted to psychologically vulnerable individuals may reduce psychologic distress and enhance compliance.

Adolescent↗
PubMed1991

Cognitive-behavioral treatment with and without response prevention for bulimia.

We compared cognitive-behavior therapy (CBT) with and without exposure and response prevention (ERP) in the treatment of eating disorder patients who both binged and purged, and reported abnormal attitudes concerning body weight and shape. Both treatments produced significant and comparable reductions in binge-eating and purging, eating patterns, and attitudes about weight and shape at posttreatment. Treatment effects were generalized to improvements in different measures of general psychopathology, and were maintained over follow-ups of 3 and 12 months. The findings are consistent with prior research showing that CBT is an effective treatment for patients with the core features of bulimia nervosa. Furthermore, the data suggest that the addition of in-session exposure and response prevention does not enhance the effectiveness of the basic CBT program.

Adult↗
PubMed1991

Male sexual fantasy: multidimensionality in content.

Sixty-six men provided ratings of the extent to which they regarded fantasies depicting nominated sexual activities as sexually arousing. A Male Sexual Fantasy Questionnaire (MSFQ) with five subscales was constructed following factor analysis of these ratings. The subscales yield separate scores for fantasies representing sensual, genital, public sex, sexual dominance-submission, and sexual aggression themes. Levels of penile tumescence recorded while men engaged in fantasies depicting content represented in the MSFQ correlated with the extent to which these men earlier had rated these same fantasies as sexually arousing. Since ratings on the MSFQ did not correlate substantially or consistently with scores on the Betts Questionnaire Upon Mental Imagery, the Imaginal Processes Inventory, and the Gordon Test of Visual Imagery Control, sexual fantasy may be mediated by processes different from those involved in non-sexual imagery and daydreaming. The need to validate use of the MSFQ in several clinical contexts is noted.

Adolescent↗