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Biomedical subjects

M Roberts

Publications and source records attributed to M Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1998

"Saturday night fever": ecstasy related problems in a London accident and emergency department.

OBJECTIVES: To report on the extent and nature of acute MDMA (ecstasy) related problems presenting to a large London hospital's accident and emergency (A&E) department. METHOD: The computerised attendance records for all patients attending the A&E department over a 15 month period were retrospectively screened. Potential cases thus identified had their case notes systematically reviewed to confirm the history of MDMA use and to extract other relevant data. RESULTS: Forty eight consecutive MDMA related cases were identified. All were in the 15-30 year age group with the majority presenting in the early hours at weekends and having consumed the drug at a night club. The mean number of tablets consumed was two and almost 40% had taken MDMA before. Polydrug use was common with half of the sample having concurrently taken another illicit substance--most commonly other stimulants (amphetamines and cocaine). A wide range of adverse clinical features was found. The most common symptoms were vague and non-specific such as feeling strange or unwell, however many patients had collapsed or lost consciousness. The most common signs elicited were related to sympathetic overactivity, agitation/disturbed behaviour, and increased temperature. The more serious complications of delirium, seizures, and profound unconsciousness (coma) were commoner when MDMA was used in combination with other substances. CONCLUSIONS: For young adults presenting late at night at weekends and exhibiting symptoms of sympathetic overactivity, disturbed behaviour, and increased temperature ("Saturday night fever") the use of stimulant dance drugs especially MDMA should be suspected. As MDMA use does not appear to occur in isolation, the clinical picture is likely to be complicated by multiple rather than single drug ingestion. This poses increased diagnostic and management challenges for A&E staff who typically represent the front line response to dance drug related problems.

Adolescent↗
PubMed1998

Hypersensitivity pneumonitis due to humidifier disease: seek and ye shall find.

STUDY OBJECTIVES: This study reports a classic case of hypersensitivity pneumonitis (HP) with classic histologic changes in lung tissue and the research used to identify the causative antigens. DESIGN: A patient with clinical, radiographic, pulmonary function abnormalities and a lung biopsy consistent with HP had no identifiable antigen exposure. SETTING: Evaluation of the patient's activities provided no suggestion of antigen exposure. Her home was evaluated. It was found that her humidifier ran continually without being cleaned but water was added periodically. MEASUREMENTS: Serologic analysis demonstrated precipitating antibodies against her humidifier water and ten antigens in the hypersensitivity lung disease serologic panel. CONCLUSION: Removal of the humidifier, cleaning of the house, and a course of prednisone resulted in the return of the patient to a normal state.

Aged↗
PubMed1998

IPS Empress: a standard of excellence.

For 10 years, clinicians have been able to provide patients with a proven aesthetic and functional restoration that exhibits wear-compatibility, durability, and marginal integrity. This leucite-reinforced, pressed ceramic (IPS Empress, Ivoclar Williams, Amherst, NY) presents to patients and dentists the option of a metal-free alternative which retains the functional advantages of a porcelain-fused-to-metal restoration. This article illustrates the importance of sound laboratory communication in the utilization of this restorative material, focusing upon three aspects: midline and incisal edge inclination, elimination of open gingival embrasures, and incisal edge translucency. Techniques are also presented in order to efficiently communicate details of each case presented to the laboratory.

Aluminum Silicates↗
PubMed1997

Salmonella typhimurium infections in mice deficient in interleukin-4 production: role of IL-4 in infection-associated pathology.

Mice harboring mutations in the IL-4 gene (IL-4(-/-)) were infected with a range of Salmonella typhimurium HWSH derivatives using different routes of infection. Compared with IL-4(+/+) mice, IL-4(-/-) mice exhibited a delayed time to death following infection with wild-type S. typhimurium HWSH. Groups of IL-4(+/+) mice infected with S. typhimurium HWSH purE, a less virulent derivative, showed sporadic deaths and harbored micro- or macroabscesses in their tissues, particularly associated with the liver. However, IL-4(-/-) mice infected with similar doses of S. typhimurium HWSH purE bacteria were resistant to killing and failed to develop detectable abscesses. Abscess formation in IL-4(-/-) mice could be induced by i.v. administration of rIL-4 during the S. typhimurium HWSH purE infection. The immune response in both IL-4(-/-) and IL-4(+/+) mice was of the Th1-type. Viable salmonella bacteria could be found associated with abscesses. Both IL-4(-/-) and IL-4(+/+) mice were resistant to killing by S. typhimurium aroA.

Animals↗
PubMed1997

Centromeric sites and cereal chromosome evolution.

Comparative genome analysis enables the sites of centromeres, telomeres and nucleolar organiser regions to be aligned with borders that define the sets of linked genes conserved across the cereal genomes. This provides a basis for studying cereal genome evolution.

Biological Evolution↗
PubMed1997

Immunization of mice with DNA encoding fragment C of tetanus toxin.

Immunization of mice with Fragment C protein, the non-toxic C-terminal domain of tetanus toxin, will protect mice against lethal challenge with tetanus toxin. A plasmid, pcDNA3/tetC, which encodes a synthetic tetC gene expressed under the control of the human cytomegalovirus major intermediate early promoter/enhancer region, was constructed. Fragment C expression was observed in Chinese hamster ovary cells following transfection with pcDNA3/tetC. The immune response induced by intramuscular immunization with pure pcDNA3/tetC DNA was evaluated in a murine model. Anti-Fragment C serum immunoglobulin and proliferative responses in splenocytes were observed following two immunizations with pcDNA3/tetC. The major IgG subclass that recognized Fragment C was IgG2a and the stimulated splenocytes secreted high levels of interferon-gamma. Sufficient anti-Fragment C serum immunoglobulins were induced by DNA-mediated immunization to protect mice against lethal challenge with tetanus toxin.

Animals↗
PubMed1997

Value of a supervised exercise program for the therapy of arterial claudication.

PURPOSE: This study was performed to test the effectiveness of a formal supervised exercise program against a home-based exercise program for both walking ability and quality of life endpoints. METHODS: Patients with arterial claudication were randomized to either a 12-week supervised exercise program (SUPEX) with weekly lectures relating to peripheral vascular disease or to a home exercise group (HOMEX) who attended an identical lecture program and received weekly exercise instruction. The study population included 29 men and 26 women, with a mean age of 69.1 +/- 8.1 years. Forty-seven patients completed the 12-week program, 46 were available for testing at completion, and 38 for 6-month testing. Claudication pain time (CPT) and maximum walking time (MWT) on a progressive treadmill exercise test were assessed at baseline, program completion, and 6 months. The Medical Outcomes Study Short Form-36 (SF-36) was administered at these intervals to assess effects on quality of life. RESULTS: Each group improved (p < 0.001) in both CPT and MWT at the completion of the 12-week program, which was sustained at the 6-month follow-up. Increase in HOMEX CPT from baseline (3.6 +/- 2.73 minutes) to 6-month follow-up (6.6 +/- 3.17 minutes) was less than for the SUPEX group (3.8 +/- 2.74 to 11.2 +/- 4.02 minutes, respectively); similar results were obtained for MWT. At both completion and 6 months, there was a significant intergroup difference for CPT and MWT (p < 0.004) favoring SUPEX. For both groups, measures of health perception based on the SF-36 demonstrated improvement (p < 0.002) in Physical Function Subscale, Bodily Pain Subscale, and Physical Composite Score. There were no between-group differences on the subsets of the SF-36 at the three assessment intervals. CONCLUSIONS: Supervised exercise programs provide superior increased walking ability in the noninterventional therapy of arterial claudication, and both supervised and home based exercise therapy result in improved SF-36 functional measures. The lack of intergroup differences in these measures may be a result of the high degree of interaction with healthcare providers in the HOMEX group. Although a supervised program results in optimal walking benefits, a highly structured home-based program provides similar functional improvement and may be a satisfactory alternative for patients with lesser walking requirements.

Aged↗
PubMed1997

Analysis of p53 gene deletions in patients with non-Hodgkin's lymphoma by dual-colour fluorescence in-situ hybridization.

The most common tumour suppressor gene altered in human cancers is p53, which is located on the short arm of chromosome 17. Structural abnormalities of the short arm and loss of chromosome 17 have been reported to confer resistance to chemotherapy in patients with non-Hodgkin's lymphoma (NHL). Therefore we studied the incidence and prognostic value of p53 deletions in patients with NHL by fluorescence in-situ hybridization using a 40 kb cosmid probe. Specimens obtained from 79 patients with NHL were studied. 46 patients were untreated, and 33 were previously treated. 40 tumours had indolent and 39 had aggressive histologies. p53 deletions were observed in 14 specimens (18%) in 32-90% of the cells. No statistically significant difference in the incidence of p53 deletion was observed between indolent and aggressive NHLs or between untreated and previously treated patients. However, p53 deletions were observed in three of four patients with transformed lymphoma. In the untreated patients, p53 deletion had no effect on response to therapy, time to treatment failure, or survival. We conclude that p53 deletions are uncommon in NHL, and may be frequent in patients with transformed lymphoma. In this study, p53 deletions did not influence treatment outcome or prognosis of NHL. Because monosomy 17 and 17p abnormalities have been reported to confer poor prognosis in NHL, other tumour suppressor genes on 17p should therefore be studied.

Aneuploidy↗
PubMed1997

Liaison psychiatric nursing in an inner city accident and emergency department.

The Mental Health Nursing Review Team recommend research to examine the potential of liaison mental health nursing. This paper describes a study into the work of two emergency psychiatric nurses (EPN) attached to a central London accident and emergency (A&E) department. A semi-structured interview schedule was employed to generate data on role development and purpose, and a retrospective survey of clinical activity was carried out over a 94-day period. Specific attributes and working practices, which promoted integration within the A&E department, are identified as are the reasons for referring patients to the EPNs, patients' primary problems on assessment, assessment outcome and the staff involved in each assessment. Findings are considered in relation to the various models of psychiatric consultation and liaison found in the literature. The scope and quality of the available data is also assessed and recommendations are made to enable a more robust prospective study to be undertaken.

Emergency Nursing↗
PubMed1997

Preliminary evaluation of a sensory and psychomotor functional test battery for carpal tunnel syndrome: Part 2--Industrial subjects.

This study evaluated the Wisconsin functional sensory and psychomotor test battery for carpal tunnel syndrome (CTS). Subjects were 27 employees recruited from a food processing plant. Both hands of all subjects were examined and categorized by presence or absence of symptoms and nerve conduction study (NCS) findings (Symptom-/NCS-, Symptom+/NCS-, Symptom-/NCS+, and Symptom+/NCS+). Symptom-/NCS- category hands had significantly better performance (15-60%) for most of the functional test battery variables than Symptom+/NCS+ category hands. A significant gap detection threshold difference (32%) was observed between NCS+ and NCS- hands regardless of symptoms, with NCS- having impaired performance. No significant effect of CTS symptoms on performance was observed. Stepwise discriminant analysis was used to select the best variables to differentiate between groups. The ratio of the change in pinch rate with respect to required pinch force differentiated NCS+ from NCS- hands, with a sensitivity of 0.71 and a specificity of 0.68. The same variable had a sensitivity of 0.74 and specificity of 0.83 for distinguishing Symptom-/NCS- hands from all other categories. Pinch rate had a sensitivity of 0.82 and a specificity of 0.81 for separating Symptom+/NCS+ hands from all other categories. Use of both gap detection threshold and the ratio of the change in pinch rate with respect to required pinch force could best differentiate Symptom+/NCS+ from Symptom-/NCS- cases for a sensitivity of 0.91 and specificity of 0.87. Outcomes could not be generalized to a specific work population but demonstrate that the non-invasive test battery may be useful for providing objective measures of deficits associated with CTS symptoms and electrophysiological parameters.

Adult↗
PubMed1997

Mechanisms of action of anti-GM1 and anti-GQ1b ganglioside antibodies in Guillain-Barré syndrome.

Anti-GM1 and anti-GQ1b ganglioside antibodies are found in association with acute and chronic peripheral neuropathies, including Guillain-Barré syndrome. They are believed to arise as a result of molecular mimicry with immunogenic microbial polysaccharides. Although anti-ganglioside antibodies are suspected to play a causal role in neuropathy pathogenesis, the details of this have yet to be proven. The approach in this laboratory to solving this issue has been to generate anti-GM1 and anti-GQ1b monoclonal antibodies from peripheral blood lymphocytes of affected patients and to study their immunolocalization in peripheral nerve and their electrophysiologic effects in animal models in which peripheral nerve sites are exposed to anti-ganglioside antibodies. These data show that anti-ganglioside antibody-reactive epitopes are widely distributed in peripheral nerve and can cause electrophysiologic abnormalities in a variety of model systems; thus, these data support the view that anti-ganglioside antibody-reactive epitopes may directly contribute to neuropathy pathogenesis.

Animals↗
PubMed1997

Laboratory evaluation of the I-NOvent nitric oxide delivery device.

The "I-NOvent delivery system" (Ohmeda Inc., Madison, WI, USA) is a device designed to add nitric oxide to a ventilator breathing system so that the inspired nitric oxide concentration remains constant in spite of changes in minute ventilation. In a laboratory study the device maintained the inspired nitric oxide concentration delivered to a model lung in the range 10.2-10.7 parts per million (ppm) when set to deliver 10 ppm, and in the range 40.5-42 ppm when set to deliver 40 ppm, for tidal volumes of 500, 700 and 900 ml, ventilator rates of 10, 15 and 20 bpm, peak inspiratory flow rates of 30, 40 and 50 litre min-1, and square, sine and decelerating ramp flow waveforms.

Drug Administration Schedule↗
PubMed1997

Utrophin abundance is reduced at neuromuscular junctions of patients with both inherited and acquired acetylcholine receptor deficiencies.

Congenital myasthenic syndromes are a heterogeneous group of conditions in which muscle weakness resulting from impaired neuromuscular transmission is often present from infancy. One form of congenital myasthenic syndrome is due to a reduction of the number of acetylcholine receptors (AChRs) at the neuromuscular junction. We describe four new cases of AChR deficiency, characterized by a reduction in both miniature endplate potential amplitude and AChR abundance accompanied by elongation of the neuromuscular junction and some decrease in postsynaptic folding. A number of cytoplasmic proteins are normally associated with the postsynaptic membrane and may contribute to the clustering of AChRs at the neuromuscular junction. We therefore investigated the expression of several of these proteins in these AChR-deficiency patients. In each patient, immunolabelling of the neuromuscular junction for rapsyn, dystrophin, beta-dystroglycan and a form of beta-spectrin was strong but that for utrophin was markedly reduced or absent. This suggested that a defect in utrophin expression might underlie the congenital AChR deficiency. However, a reduction in utrophin labelling was also seen in three patients with adult acquired autoimmune myasthenia gravis in whom AChR loss results directly from the extracellular binding of autoantibodies. We conclude that the loss of AChRs in AChR deficiency does not result from the absence of rapsyn or beta-dystroglycan and that reduction of utrophin is probably secondary to the loss of AChRs. The possible role of AChRs and/or utrophin in determining the extent of postsynaptic folding is discussed.

Action Potentials↗
PubMed1997

Detailed comparative mapping of cereal chromosome regions corresponding to the Ph1 locus in wheat.

Detailed physical mapping of markers from rice chromosome 9, and from syntenous (at the genetic level) regions of other cereal genomes, has resulted in rice yeast artificial chromosome (YAC) contigs spanning parts of rice 9. This physical mapping, together with comparative genetic mapping, has demonstrated that synteny has been largely maintained between the genomes of several cereals at the level of contiged YACs. Markers located in one region of rice chromosome 9 encompassed by the YAC contigs have exhibited restriction fragment length polymorphism (RFLP) using deletion lines for the Ph1 locus. This has allowed demarcation of the region of rice chromosome 9 syntenous with the ph1b and ph1c deletions in wheat chromosome 5B. A group of probes located in wheat homoeologous group 5 and barley chromosome 5H, however, have synteny with rice chromosomes other than 9. This suggests that the usefulness of comparative trait analysis and of the rice genome as a tool to facilitate gene isolation will differ from one region to the next, and implies that the rice genome is more ancestral in structure than those of the Triticeae.

Chromosome Mapping↗
PubMed1997

Iron-regulated excretion of alpha-keto acids by Salmonella typhimurium.

Excretion of alpha-keto acids by clinical isolates and laboratory strains of Salmonella typhimurium was determined by high-performance liquid chromatography analysis of culture supernatants. The levels of excretion increased markedly with increasing iron stress imposed by the presence of alpha,alpha'-dipyridyl or conalbumin in the medium. The major product was pyruvic acid, but significant concentrations of alpha-ketoglutaric acid, alpha-ketoisovaleric acid, and alpha-ketoisocaproic acid were also observed. Maximal excretion occurred at iron stress levels that initially inhibited bacterial growth; the concentration of alpha,alpha'-dipyridyl at which this was observed differed between strains depending on their ability to secrete and utilize siderophores, suggesting that the intracellular iron status was important in determining alpha-keto acid excretion. However, prolonged incubation of the siderophore-deficient S. typhimurium strain enb-7 under conditions of high iron stress resulted in significant delayed bacterial growth, promoted by tonB-dependent uptake of iron complexed with the high accumulated levels of pyruvic acid and other alpha-keto acids. Strain RB181, a fur derivative of enb-7, excreted massive amounts of alpha-keto acids into the culture medium even in the absence of any iron chelators (the concentration of pyruvic acid, for example, was >25 mM). Moreover, RB181 was able to grow and excrete alpha-keto acids in the presence of alpha,alpha'-dipyridyl at concentrations threefold greater than that which inhibited the growth of enb-7.

2,2'-Dipyridyl↗