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Biomedical subjects

M Thompson

Publications and source records attributed to M Thompson.

At least 73 records · Page 4Linked to original sources
PubMed1998

Protein adsorption to organosiloxane surfaces studied by acoustic wave sensor.

Surfaces of the two organosiloxanes, polymercaptopropylmethylsiloxane and octaphenylcyclotetrasiloxane, were prepared on the gold electrodes of thickness-shear mode acoustic wave sensors. Compounds containing the siloxane bond are important in the fabrication of medical implants. The flow-through adsorption of the proteins: human serum albumin, alpha-chymotripsinogen A, cytochrome c, fibrinogen, hemoglobin, immunoglobulin G and apo-transferrin to the two siloxane surfaces and a gold electrode were detected by acoustic network analysis. With the exception of minor wash-off by buffer flow, the adsorption of all proteins to the three surfaces is irreversible. Differences observed for the magnitudes of adsorption for the various cases are ascribed to the role played by molecular interactions at the liquid/solid interface. The results confirm that changes in series resonant frequencies caused by macromolecular adsorption differ significantly from the widely accepted "mass based" model usually employed to characterize the response of this type of acoustic wave device.

Adsorption↗
PubMed1998

Hybridization of complementary strand and single-base mutated oligonucleotides detected with an on-line acoustic wave sensor.

The hybridization of a biotinylated 25-mer oligonucleotide probe with complementary, non-complementary and single-base mutated 25-mer targets at the liquid-solid (neutravidin-modified) interface of a thickness-shear mode acoustic wave device was studied. The sensor was incorporated into an on-line configuration capable of both variable flow and stop-flow experiments. Under ambient temperature conditions different signals were obtained for the complementary and non-complementary cases. At higher temperatures, the former system exhibits behaviour characteristic of the production of intermediate duplexes which are decomposed by the re-introduction of buffer solution. The use of these conditions allows the distinction of binding events involving a set of single-base mutated 25-mers. Different responses were obtained depending on both the nature of the instigated mismatch in base pairing and on the location of mutation.

Biosensing Techniques↗
PubMed1998

Pantoprazole-based 10-day triple therapy is effective in Helicobacter pylori eradication.

AIM: To investigate the efficacy of a short course of pantoprazole-based triple therapy in Helicobacter pylori eradication in a single-centre pilot study. METHODS: Patients with active or healed duodenal ulcer or with gastric erosions or gastritis, all of whom were H. pylori-positive, received 10 days of twice-daily open treatment with pantoprazole 40 mg, plus clarithromycin 250 mg and tinidazole 500 mg. H. pylori was assessed at entry and 28-35 days after the end of treatment by rapid urease test (at entry only), culture and antimicrobial sensitivity, histology and 13C urea breath test. The criterion for eradication was a negative result in all three tests. RESULTS: Seventy patients were treated, of whom four were excluded from analysis due to major deviations from the study protocol. Eradication of H. pylori was achieved in 57/66 patients (per protocol analysis 86% (95% CI: 78-95%)) and was higher in patients with organisms sensitive to nitroimidazole before treatment (sensitive: 47/53 (89%), insensitive: 10/13 (77%)). There was marked reduction in acute gastritis throughout the stomach while chronic gastritis decreased only in the corpus. Healing was achieved in all 24 patients with active duodenal ulcer. Treatment was complied with; only one patient missed one of the 20 doses. Adverse events were of mild or moderate intensity and did not require withdrawal from treatment. CONCLUSION: A short course of pantoprazole-based triple therapy is well tolerated and effective in eradicating H. pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

Techniques to evaluate elderly human muscle function: a physiological basis.

Elderly persons appear to exhibit muscle weakness and a slowing in their speed of muscle movement. Objective quantification of these characteristics requires reliable and practical tests to assess the muscle contractile characteristics of elderly people. This review discusses the advantages and limitations of voluntary and electrically stimulated muscle testing techniques used to assess the strength, speed, and fatigability of elderly muscle with a brief explanation of the physiological basis. This review presents the practice and theory underlying the scientific measurement of elderly human muscle function, bridging the gap between the practical issues of measurement and the physiological significance of such measurements.

Adult↗
PubMed1998

The effects of nursing case management on the utilization of prenatal care by Mexican-Americans in rural Oregon.

This quasi-experimental, retrospective study used birth certificate and medical record data to evaluate the effectiveness of the Rural Oregon Minority Prenatal Program (ROMPP) in improving patterns of prenatal care utilization by rural-dwelling, low-income, Mexican-American women at risk of poor pregnancy outcomes. The ROMPP intervention provided nursing case management services and peer outreach to pregnant Mexican-American women in a rural Oregon community. The intervention group had more prenatal visits in months 2, 3, 4, 5, 6, and 7 than the comparison group (P < 0.05). The intervention group had a similar number of emergency room (ER) visits, but had more respiratory diagnoses and fewer urinary tract infections. ROMPP women had more inpatient admissions and longer lengths of stay. No differences were found in the initiation of prenatal care or the total number of prenatal care visits, nor in the timing of screening serum glucose tests. The intervention should be expanded to address the persistent attitudinal, financial, transportation and language barriers to adequate prenatal care. Nurses should increase their cultural competency and sharpen their clinical focus on advocacy, marketing, facilitation of relationships between community groups, and community organizing.

Adolescent↗
PubMed1998

Behavioral risk factors in emergency department patients: a multisite survey.

BACKGROUND: Many people rely on EDs for routine health care. Often, however, screening and counseling for health risks are not provided. OBJECTIVE: To determine prevalence rates of chronic disease and injury risk factors and access to routine health care in a random sample of ED patients in 3 cities. METHODS: A prospective survey was conducted at 3 hospital EDs in Akron, OH, Boston, MA, and Denver, CO. A modified version of the national Behavioral Risk Factor Surveillance Survey was administered by trained researchers to a convenience sample of non-critically ill patients during randomly selected shifts. RESULTS: Of 1,143 eligible patients, 923 (81%) agreed to participate. Their mean age was 39 (range = 17-96) years. Most were female (58%), white (60%), and unmarried (68%). Thirty-eight percent had no access to primary care. Injury-prone behaviors were prevalent: 53% of the respondents did not wear seat belts regularly; 15% had no working smoke detector; 3% kept loaded, unlocked handguns in their homes; 11% had attempted suicide; 23% had a positive CAGE screen for alcoholism; 3% had operated a motor vehicle in the preceding month while alcohol-intoxicated; and 11% had ridden in an automobile with an intoxicated driver. Cancer and chronic disease risks were also common: 48% smoked; 16% had not received a blood pressure check in the preceding year; and 4% reported unsafe sexual practices. Among women aged > 50 years, 42% had not received a Pap test in the prior 2 years and 14% had never had mammography. Many prevalence rates and access to care varied among the 3 sites. However, for most risk factors, prevalence rates did not differ in patients with and without access to primary health care. CONCLUSIONS: ED patients have high rates of injury and chronic disease risks, and many have no other source of routine health care. Research is needed to determine whether ED-based programs, designed to reduce injury and chronic disease risks, are feasible and cost-effective.

Adolescent↗
PubMed1998

The flat electrocardiogram--systole or asystole?

A case of stone heart syndrome is reported in a pregnant 27 year old West African patient, who suffered syncopal symptoms shortly before cardiac arrest. The electrocardiographic features were those of asystole, but direct examination of the heart at emergency thoracotomy in the A&E department revealed tetanic contracture of the organ. At necropsy, the heart was of normal weight but showed areas of fibrosis surrounding the bundle of His. The discrepancy between the ECG features and the physiological state of the heart raises the possibility that other cases of apparent asystole may not be what they seem.

Adult↗
PubMed1998

Erosive oesophagitis: outcome of repeated long term maintenance treatment with low dose omeprazole 10 mg or placebo.

AIMS: To investigate the efficacy of daily maintenance treatment with omeprazole 10 mg in reducing the relapse rate of healed erosive oesophagitis. METHODS: Three hundred patients with erosive oesophagitis (grade 2 or greater) received omeprazole 20 mg daily for 12 weeks, followed by 40 mg daily for a further 12 weeks if required. After healing, patients were randomised to double blind treatment with omeprazole 10 mg daily or placebo for up to 18 months. On relapse the treatment cycle was repeated. RESULTS: The cumulative healing rate at 12 weeks in the initial healing period was 95%, and 96% and 98% on rehealing courses after relapse in the first and second maintenance periods respectively. After 12 weeks of treatment, 98% of patients were free from heartburn and 97% were free of all reflux related symptoms. Relapse in the subgroup of patients who relapsed in both maintenance periods was infrequent on omeprazole 20 mg daily: only 9% at two years. Gastrin concentrations rose above normal in one third of patients. One patient had linear hyperplasia of endocrine cells and another had micronodular hyperplasia. There were no side effects definitely attributable to omeprazole. CONCLUSION: Maintenance treatment with omeprazole 10 mg daily keeps about 60% of patients with erosive oesophagitis in prolonged remission. Patients relapsing once are likely to do so again; they can subsequently be treated effectively with omeprazole 20 mg daily.

Anti-Ulcer Agents↗
PubMed1998

A novel interaction between inhibitory melatonin receptors and protein kinase C-dependent signal transduction in ovine pars tuberalis cells.

This study revealed an important and unexpected finding: namely, that inhibitory melatonin receptors can inhibit a phorbol 12,13 myristate acetate (PMA)-induced, protein kinase C (PKC)-dependent increase in c-fos messenger RNA expression in ovine pars tuberalis (PT) cells. PMA induces dose-dependent stimulation of c-fos expression that is attenuated by melatonin in a dose-dependent and pertussis toxin-sensitive manner. The effect of 100 nM PMA is blocked by Ro31-8220 (1 microM), yet is not mimicked by 4alpha-PMA (100 nM). PMA (100 nM) induces PKC activity in PT cells (P < 0.05) within 5 min, but melatonin has no effect on this response. PMA (100 nM) stimulates both phospholipase D and mitogen-activated protein kinase (MAPK) (p42/44) activities in PT cells, but melatonin has no effect on these responses. The results indicate that neither of these second-messenger activities contribute to the melatonin-sensitive pathway of c-fos activation. The MEK (MAPK kinase) inhibitor, PD98059 (50 microM), does not block the induction of c-fos by PMA, although at the same dose it inhibits PMA-mediated activation of p42/44 MAPK by 50-70%, and activation by forskolin or insulin-like growth factor-I by 100%. These data suggest that p42/44 MAPK may not be the primary mediator of PKC-dependent c-fos induction. In contrast to the effect of melatonin on PMA-mediated c-fos induction in PT cells, in L cells stably transfected with the sheep Mel1 alphabeta receptor, melatonin potentiates the c-fos response in a pertussis toxin-sensitive manner. These data indicate the tissue-specific nature of melatonin receptor signaling, and reveal that a pertussis toxin-sensitive pathway can block PKC-mediated c-fos induction in PT cells.

Animals↗
PubMed1998

Chorionic morphology of eggs of the Psorophora confinnis complex in the United States. II. Pre- and postdeposition studies of Psorophora Columbiae (Dyar and Knab) eggs.

Scanning and transmission electron microscopic techniques were used to determine the morphology of the exochorion and endochorion of Psorophora columbiae eggs as found in the ovary and after deposition. In the ovary, the outer chorionic reticulations and tubercles of the eggs are ornately developed below the follicular epithelium. Expansion of the eggs after deposition causes the outer chorionic reticuli and sculpturing (i.e., minor and major tubercles) to form the characteristic spinose appearance of Psorophora eggs. Transmission electron microscopic micrographs of cross and sagittal sections of the chorionic layers of Ps. columbiae eggs indicate that the major outer chorionic tubercles have 3 distinct regions. The 3rd region was found only on the dorsum of the tubercle. Elevation of major tubercles appears to be regulated, at least in part, by ambient moisture conditions, and one function of these tubercles seems to be adhesion of the egg to an oviposition surface.

Animals↗
PubMed1998

The contribution of classical (beta1/2-) and atypical beta-adrenoceptors to the stimulation of human white adipocyte lipolysis and right atrial appendage contraction by novel beta3-adrenoceptor agonists of differing selectivities.

The role of beta3- and other putative atypical beta-adrenoceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta3-adrenoceptor (beta3AR) agonists with varying intrinsic activities and selectivities for human cloned betaAR subtypes. The ability to demonstrate beta1/2AR antagonist-insensitive (beta3 or other atypical betaAR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta3AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta1/2AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta3AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta1/2AR antagonism, despite it having very low efficacies at cloned beta1- and beta2ARs. A component of the response to another phenylethanolamine selective beta3AR agonist (SB-215691) was insensitive to beta1/2AR antagonism in some experiments. Because no [corrected] novel aryloxypropanolamine had a beta1/2AR antagonist-insensitive inotropic effect, these results establish more firmly that beta3ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta4ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned betaARs which betaARs will mediate responses to agonists in tissues that have a high number of beta1- and beta2ARs or a low number of beta3ARs.

Adipose Tissue↗
PubMed1998

Molecular biology of septic shock.

Septic shock is a complex pathophysiologic state which often leads to multiple organ dysfunction, multiple organ failure, and death. This review summarizes current views on the molecular biology of three aspects of septic shock: recognition of bacterial invasion and induction of the cytokine response; genetic variability among humans and their predispositions toward pathologic inflammatory responses; and the signal transduction mechanisms which account for the transfer of molecular signals from cytokine receptors on the plasma membrane to cytokine-responsive genes in the nucleus. In particular, the review summarizes the pathway involved in tumor necrosis factor signaling through nuclear factor-kappaB, and elucidates the molecular signals involved in inflammatory responses and apoptosis.

Apoptosis↗
PubMed1998

Antibacterial activity of antibiotic coated silicone grafts.

PURPOSE: Postoperative infection remains one of the most serious complications of implantation of penile prostheses. Attempts to reduce the rate of infection by spraying the prosthesis with an antibiotic solution prior to implantation, along with perioperative antibiotics, have failed to eradicate infection. No published studies have evaluated the effect of antibiotic coating of penile prostheses. In this study, we evaluate the antibacterial effect of antibiotic-coated silicone strips as a surrogate for the penile prosthesis. MATERIALS AND METHODS: Strips coated with several different antibiotics were dipped in bacterial solutions containing Staphylococcus epidermidis or S. aureus and implanted subcutaneously in adult Sprague-Dawley rats. After a week, the strips were removed, and the number of bacteria on the strips and in the surrounding tissue were determined. The in vitro antibiotic activity of the antibiotic-coated strips against the same organisms was also determined. RESULTS: In the group of rats that received silicone strips contaminated in vitro with S. epidermidis, six of nine control rats yielded strips and tissues containing heavy bacterial growth. None of six strips coated with rifampin/minocycline yielded bacterial growth, nor did any of the seven strips coated with vancomycin. One of seven rats that received amikacin-coated strips had infection of the strip. The tissue results were similar to the strip results. In the group using S. aureus as the contaminating bacterium, the strips and tissues from eight of nine control rats yielded bacteria. None of the six rifampin/minocycline-coated strips yielded bacteria, while two of seven vancomycin-treated strips and two of six amikacin-coated strips were infected with S. aureus. The difference in bacterial growth between controls and antibiotic-coated strips reached a level of statistical significance for the rifampin/minocycline and vancomycin groups and was highly significant for the rifampin/minocycline groups. CONCLUSION: The experimental results presented here suggest that coating silicone graft material with antibiotics, particularly rifampin/minocycline, can reduce the incidence of graft colonization in contaminated wounds in rats, even in the absence of systemic antibiotics. These graft materials may prove useful in preventing the infection of penile prostheses.

Animals↗