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Biomedical subjects

M Morgan

Publications and source records attributed to M Morgan.

At least 91 records · Page 5Linked to original sources
PubMed2000

Prognostic factors in malignant gastrointestinal stromal tumors.

Gastrointestinal stromal tumors are a heterogeneous group of mesenchymal neoplasms of the gastrointestinal tract in which routine histopathological evaluation fails to reveal definitive evidence of differentiation. Given the heterogeneity in clinical presentation and the frequent morphological overlap, the biological behavior of these neoplasms is difficult to predict. We have evaluated, by Cox Proportional Hazards Regression Analysis, the clinicopathological features of 51 malignant gastrointestinal stromal tumors to identify predictors of survival. In the univariate analysis, survival inversely correlated with size, number of mitoses, and patient's age. In the multivariate analysis, only the degree of necrosis and phenotypic differentiation toward smooth muscle were found to be indicators of poor prognosis. Based on these results, a simple classification scheme for gastrointestinal stromal tumors is proposed. This classification appears to have great prognostic value for these tumors, and may be useful in guiding therapeutic management.

Adult↗
PubMed2000

Antibiotic resistance patterns of group B streptococcus in antenatal genital cultures.

OBJECTIVE: To identify the antibiotic susceptibility patterns of group B streptococcus (GBS) isolated from antenatal genital screening cultures. STUDY DESIGN: One hundred thirty-five sequential GBS isolates underwent susceptibility testing by Kirby-Bauer disk diffusion to a variety of commonly used antibiotics. RESULTS: All isolates were susceptible to cefazolin, chloramphenicol and vancomycin. Resistance to clindamycin and erythromycin, the currently recommended alternative antibiotics for intrapartum GBS prophylaxis in penicillin-allergic women, was found in 8.2% and 9.6% of GBS isolates tested, respectively. CONCLUSION: These findings raise concerns regarding the need for both confirmation of a history of penicillin allergy in pregnant women and performance of antibiotic susceptibility testing on GBS isolated in genital screening cultures from penicillin-allergic patients.

Anti-Bacterial Agents↗
PubMed2000

Dental laser identifies early stages of caries.

In conclusion, the various methods of caries detection used, including visual inspection, radiographs, and tactile sensation, have a significant subjective component. The Diagnodent allows clinicians to add a more objective test to their armamentarium. Should the doctor choose to "watch" a suspected lesion and treat with topical fluoride, the area can be monitored for the progression or regression of decalcification. For more information, call KaVo at (888) KaVo-USA.

Adult↗
PubMed1999

Hormones, genes and the structure of sexual arousal.

Despite the inherent difficulty of connecting individual genes with integrated mammalian behaviors, it has been determined that a series of genes are turned on by estrogenic hormones acting in forebrain. Their products are, in turn, facilitatory for female reproductive behaviors such as lordosis. The causal routes by which two genes contribute to the control of lordosis behavior, the classical estrogen receptor gene (ER-alpha) and a thyroid hormone (TH) receptor gene (TR-beta), have been delineated. Beyond the mechanisms underlying the expression of concrete, specific natural behaviors, lies the question of sexual motivation. Required as an intervening variable to explain fluctuations in natural behaviors in the face of constant stimuli, motivational states have both general and specific features. Most theoretical and experimental approaches toward the general aspects of motivation have depended heavily on concepts of 'arousal.' Sexual arousal is likely to depend both on very general, broadly distributed neuronal influences and on specific affiliative and sexual tendencies. Is 'general arousal' a monolithic, undifferentiated process? In no way can a review at this time settle such issues, but the reasons behind six new experimental approaches to these questions are described.

Animals↗
PubMed1999

Effects of dark-rearing on triphenyl phosphate-induced neuropathy in the visual system of the developing European ferret (Mustela putorius furo).

Results of a previous study in our lab (Tanaka et al., 1994) suggested that the onset of susceptibility to the organophosphorus compound triphenyl phosphite (TPP) in the developing ferret visual system might be closely related to eye opening and the onset of light stimulation. In order to explore this idea further, TPP was administered to ferret kits that had been raised for varying periods of time in total darkness to assess whether a delay in the onset of light stimulation to the visual system might also result in a delay in its susceptibility to TPP. Ferret kits were raised from birth either in total darkness or in open-sided sheds exposed to ambient light, injected subcutaneously with TPP (888 mg/kg body weight) at 5.5, 7.5, 9.5, or 21.5 wk of age, euthanized, and perfused transcardially with a 10% formalin-saline solution 4 d after injection. Brains were sectioned parasagittally at a thickness of 40 microm and subsequently processed with the Fink-Heimer silver impregnation technique to reveal the presence of degenerating axons and terminals, and with cresyl violet stain to delineate nuclear boundaries and cell soma morphology. Comparisons among degeneration patterns present in light-reared and dark-reared kits at the four ages examined revealed that the time of onset, extent, and density of TPP-induced axonal and terminal degeneration seen in the lateral geniculate nucleus and primary visual cortex did not differ significantly between light- and dark-reared groups, with the possible exception of dark-reared kits exposed to TPP at 7.5 wk of age. In addition, neurons in the primary visual cortex showed shrinkage and increased packing densities in kits exposed to TPP in both light and dark environments, as well as in dark-reared non-injected kits. The results of this study indicate that dark-rearing does not delay the onset or lessen the severity of TPP-induced axonal and terminal degeneration in the developing visual system of the ferret. Data suggest that light activation and stimulation of the retino-geniculo-striatal visual pathway is not a necessary prerequisite for the onset of visual system susceptibility to the axonopathic effects of triphenyl phosphite.

Animals↗
PubMed1999

The use of regenerable, affinity ligand-based surfaces for immunosensor applications.

The regeneration of antibody-binding surfaces is of major importance for re-usable sensor formats such as required for direct 'real-time' biosensing technologies and is often difficult to achieve. Antibodies commonly bind the antigen with high avidity and may themselves be sensitive to regeneration conditions. The interaction of polyclonal anti-chlorpyriphos antibody with an immobilised chlorpyriphos-ovalbumin (chlor-oval) conjugate and the interaction of soluble recombinant CD4 with covalently immobilised anti-CD4 IgG are presented in order to highlight these difficulties. Affinity-capture is suggested as an alternative format as it facilitates surface regeneration, directed immobilisation and the attainment of interaction progress curves that conform to the ideal pseudo-first-order kinetic interaction model. Protein A, protein G and polyclonal anti-mouse Fe-coated surfaces were used to observe the interaction of captured anti-GST monoclonal antibody with glutathione-s-transferase (GST). It was shown that a protein A affinity-capture surface produced ideal interaction progress curves while both protein G and polyclonal anti-mouse Fe resulted in systemic deviations.

Affinity Labels↗
PubMed1999

Sensory perception: supernormal hearing in the blind?

A recent experimental study suggests that blind individuals may compensate for their lack of vision with better-than-normal hearing. This provides support for a view dating back to 18th century philosophers, but the data raise as many problems as they solve.

Auditory Threshold↗
PubMed1999

Lack of efficacy of 24-h infusional topotecan in platinum-refractory ovarian cancer: A Gynecologic Oncology Group trial.

BACKGROUND: The aim of this study was to evaluate the efficacy of a more convenient topotecan administration schedule in the second-line treatment of advanced platinum-refractory ovarian cancer. METHODS AND MATERIALS: The Gynecologic Oncology Group conducted a Phase II trial of 24-h infusional topotecan (8.5 mg/m(2)), repeated every 3 weeks in 26 patients with platinum-refractory ovarian cancer (failure to respond to initial platinum-based treatment or development of recurrent disease within 6 months of completion of chemotherapy). RESULTS: Grade 4 neutropenia (85% of patients) and thrombocytopenia (12%) were the major toxicities encountered. Of the 25 patients evaluable for response, only a single patient experienced an objective response (4%). CONCLUSIONS: When employed at this dose and schedule (24-h infusion every 3 weeks), topotecan has minimal second-line activity in platinum-refractory ovarian cancer.

Adult↗
PubMed1999

All Wales surveillance of methicillin-resistant Staphylococcus aureus (MRSA): the first year's results.

Over the last five years, hospitals in Wales have experienced difficulties with increasing numbers of isolates of methicillin-resistant Staphylococcus aureus (MRSA). Continuous total population surveillance of MRSA was introduced with the objectives of gaining an understanding of the extent and variation in time and place of its occurrence, the burden of disease and possible risk factors associated with its isolation and resistance to other antibiotics. All first isolates of MRSA from both hospital and community settings and all isolates of methicillin-sensitive Staphylococcus aureus (MSSA) associated with bacteraemia and cerebrospinal fluid (CSF) isolates detected in medical microbiology laboratories in Wales were collected via CoSurv, a set of interconnected data-base modules for communicable disease control. A data set was collected on each isolate and the patient associated with that isolate and compiled centrally at CDSC (Wales) for all-Wales analysis of the MRSA situation. Surveillance started in January 1996 and at the end of the first year, 2700 new isolates of MRSA had been reported from hospital and community settings, giving a rate of 92.43/100,000 population. The incidence of MRSA from bacteraemias and CSF was 5.20/100,000 compared with 12.70/100,000 for MSSA. MRSA from bacteraemia and CSF was significantly more commonly associated with male patients than MSSA. MRSA patients were significantly older. For all MRSA isolates, the highest reporting rate was in men aged 75+ (647.21/100,000). The highest incidence of invasive disease was also in men aged 75+ (45.69/100,000). Isolates from post-surgical patients were more likely to be involved in invasive disease (OR = 2.59), P < 0.001) than strains from other sources. The majority of isolates were resistant to at least two antibiotics in addition to methicillin, most frequently erythromycin and the fluoroquinolones. Very little resistance to fusidic acid, mupirocin or rifampicin was reported. Continuous total population surveillance has provided a minimum incidence of MRSA in Wales and has allowed a simple and intelligible picture of the problem to be determined, which has been fed back to hospitals to assist decisions on control.

Adolescent↗
PubMed1999

The information superhijack.

Infection control teams are not alone in their need to manipulate data. How best can such manipulation be achieved and what tools are available to turn information into knowledge. The workshop included discussion and demonstration of some methods currently being used by infection control teams. While the workshop did not aim to produce all the answers, participants were able to question, discuss and learn new ways that they might take their own practice in the future.

Cross Infection↗
PubMed1999

Promoting self-care in epilepsy: the views of patients on the advice they had received from specialists, family doctors and an epilepsy nurse.

The aim of the study was to examine patients' satisfaction with information and advice on epilepsy and self-care provided by medical specialists, general practitioners and a special nurse. We interviewed patients following a trial of nurse-run clinics for epilepsy in general practice. 44 patients, two-thirds of whom had at least one epilepsy attack in the prior 6 months were seen in their homes in the south of England. A recurring theme from interview data was that patients perceived the doctors' time as too limited to explain the condition and how to manage it, whilst the nurse had the time and expertise to do so. Overall the nurse trained in epilepsy care was valued highly for providing advice and support, especially in explaining the social aspects of epilepsy. Patients expressed the belief that they would have benefited most by seeing a special nurse at the time when epilepsy was first diagnosed.

Adolescent↗
PubMed1999

Attachment tests of Pasteuria penetrans to the cuticle of plant and animal parasitic nematodes, free living nematodes and srf mutants of Caenorhabditis elegans.

Populations of Pasteuria penetrans isolated from root-knot nematodes (Meloidogyne spp.) and cyst nematodes (Heterodera spp.) were tested for their ability to adhere to a limited selection of sheathed and ex-sheathed animal parasitic nematodes, free living nematodes, including Caenorhabditis elegans wild type and several srf mutants, and plant parasitic nematodes. The attachment of spores of Pasteuria was restricted and no spores were observed adhering to any of the animal parasitic nematodes either with or without their sheath or to any of the free living nematodes including C. elegans and the srf mutants. All spore attachment was restricted to plant parasitic nematodes; however, spores isolated from cyst nematodes showed the ability to adhere to other genera of plant parasitic nematodes which was not the case with spores isolated from root-knot nematodes. The results are discussed in relationship to cuticular heterogeneity.

Animals↗
PubMed1999

Chemical labyrinthectomy and cochlear implantation for Menière's disease--an effective treatment or a last resort?

The surgical management of Menière's disease presents a difficult and controversial problem and includes various procedures ranging from 'placebo operations' to vestibular nerve section. The situation is even more complex in the case where the only hearing ear is affected. We present a case of severe debilitating vertigo due to Menière's disease that was treated by chemical labyrinthectomy and cochlear implantation. This unique management strategy allowed restoration of useful hearing and relief of vertigo.

Audiometry, Pure-Tone↗
PubMed1999

Resistance to methicillin in isolates of Staphylococcus aureus from blood and cerebrospinal fluid in Wales, 1993-1997.

Surveillance data for organisms isolated from blood cultures and cerebrospinal fluid (CSF) specimens has been gathered electronically in Wales since 1993. Over this period the proportion of total reported organisms from blood cultures and CSF represented by methicillin-resistant staphylococci (MRSA) has risen steadily. This has corresponded to a rise in rates of methicillin resistance amongst Staphylococcus aureus isolated from blood cultures and CSF from 4 to 43%. In certain age/gender groups in 1997, more than 50% of isolates of S. aureus were resistant to methicillin, suggesting that a change in empirical treatment may be necessary for suspected staphylococcal sepsis.

Adolescent↗
PubMed1999

p53, mdm-2, and p21 waf-1 in the porokeratoses.

The etiology of the porokeratoses is unknown. Overexpression of the p53 tumor suppressor protein and disregulated cell cycle control have been pathogenically implicated. The p53 tumor suppressor gene product is regulated by mdm2 and both gene products influence cell cycle progression through the cyclin-dependent kinase inhibitor p21. Thirty-three cases of the various types of porokeratosis were immunohistochemically studied for p53, mdm2, and p21 proteins. Each of the cases showed increased p53 and decreased mdm2 and p21 expression within keratinocytes underlying cornoid lamella. This study confirms the previous findings of increased p53 staining and expands the potential roles of mdm2 and p21 in the pathogenesis of the porokeratoses.

Cyclin-Dependent Kinase Inhibitor p21↗