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Biomedical subjects

M Allen

Publications and source records attributed to M Allen.

At least 163 records · Page 9Linked to original sources
PubMed1993

Association of insulin-dependent diabetes mellitus in Taiwan with HLA class II DQB1 and DRB1 alleles.

The allelic constitution at HLA class II DRB1, DQB1, DQA1, and DPB1 loci of IDDM patients from Taiwan was compared with that of ethnically matched nondiabetic individuals by PCR-based DNA typing. Of the three haplotypes found to be positively associated with IDDM in Taiwan, two (DRB1*0301-DQA1*0501-DQB1*0201 and DR4-DQA1*0301-DQB1*0302) appear to be identical to the susceptible haplotypes in Caucasian and black populations, whereas the third haplotype (DR4-DQA1*0301-DQB1*04) has been reported to be positively associated with IDDM only in the Japanese population. The three haplotypes, DRB1*1502-DQA1*0102-DQB1*0601 and DRB1*1201 (or 1202)-DQA1*0501-DQB1*0301 and DRB1*0803-DQA1*0103-DQB1*0601, were negatively associated with IDDM in Taiwan; a protective effect of the last haplotype has not been reported previously. Neither DQ beta non-Asp-57 nor DQA1*0301 alone appears sufficient to account for the HLA-associated susceptibility to IDDM in Taiwan. Also, the DQ alpha beta heterodimer encoded by the alleles DQA1*0301/DQB1*0201, DQA1*0301/DQB1*0302, or DQA1*0501/DQB1*0201 does not explain the susceptibility of a larger fraction of the IDDM patients than the residue at position 57 of the DQ beta chain or DQA1*0301. Finally, the DRB1 alleles appear to affect IDDM susceptibility, although for most haplotypes the effect of individual loci cannot be assessed due to the linkage disequilibrium between the DQ and the DR region.

Adult↗
PubMed1993

Nocturnal desaturation and serum erythropoietin: a study in patients with chronic obstructive pulmonary disease and in normal subjects.

1. To clarify the relationship between nocturnal oxygen desaturation and erythropoietin production in patients with chronic obstructive pulmonary disease, we determined arterial oxygen saturation and serum immunoreactive erythropoietin levels over 24 h in eight patients with chronic obstructive pulmonary disease and in nine normal subjects. 2. In the normal subjects, there was a significant circadian variation in serum erythropoietin levels with the highest mean deviation from the geometric mean at 22.00 hours and the nadir at 05.00 hours. 3. The three patients with chronic obstructive pulmonary disease with the most marked nocturnal desaturation (lowest arterial oxygen saturation < 57%) and most marked daytime hypoxaemia (daytime arterial partial pressure of oxygen < 6 kPa) had raised nocturnal serum erythropoietin levels. In two of these patients, the serum erythropoietin level was raised throughout the 24 h and erythrocyte mass was also raised. In the other patient, the serum erythropoietin level was not raised in five daytime samples and erythrocyte mass was normal. 4. The other five patients with chronic obstructive pulmonary disease with less severe nocturnal hypoxaemia (lowest arterial oxygen saturation range 78-86%) had serum erythropoietin levels (range 14-36 m-i.u./ml) which were indistinguishable from normal (range 12-44 m-i.u./ml) and showed circadian changes which were not significantly different (P = 0.35) from those in the normal subjects. 5. Thus, mild nocturnal oxygen desaturation is not associated with elevation of serum erythropoietin levels, whereas daytime hypoxaemia with associated severe nocturnal desaturation is associated with increased serum erythropoietin levels both by day and by night.

Aged↗
PubMed1993

Insights from latent partition analysis into categories inherent in wellness-illness.

How health-disease is perceived or conceptualized is important for nursing research. There is increasing evidence that individual representations are important in constructing the experience of health-disease. What is the personal saliency of health-disease for the individual? To explore the patterns of meaning inherent in health-disease, a card sort was undertaken among 15 healthy individuals and 15 individuals with chronic renal disease. Both groups were given 28 cards to sort twice: once for when they felt 'well' and again for when they felt 'ill'. The theoretical basis underlying the items of the card sort was a model of wellness-illness being developed. Latent partition analysis was used to cluster the concepts from each data set followed by multi-dimensional scaling to analyse the structure of the intercategory probability estimates. A possible unidimensional pattern of meaning (harmony) emerged for the 'well' data and a two-dimensional pattern (disharmony and optimism) for the 'ill' data. This represents a preliminary step in the development of a theoretical model that would permit assessment of the meaning of health-disease for the individual.

Adult↗
PubMed1993

Four-state MVR-PCR: increased discrimination of digital DNA typing by simultaneous analysis of two polymorphic sites within minisatellite variant repeats at D1S8.

Minisatellite variant repeat mapping by PCR (MVR-PCR) provides a digital approach to DNA typing that can reveal huge levels of variation at minisatellite loci. MVR-PCR has so far been applied to three human minisatellites, including the hypervariable locus D1S8. Previous analysis at D1S8 was based on the discrimination of repeat unit types that differ by a single base substitution. We now show that a second polymorphic site within D1S8 repeats may be assayed simultaneously with the first to define four classes of repeat units ('four-state MVR-PCR'). This approach can also be applied to the other end of D1S8 alleles in 'reverse four-state MVR-PCR'. Both of these procedures substantially increase the informativeness of MVR analysis at D1S8 and should prove useful in studies of minisatellite biology and potentially in forensic DNA typing.

Alleles↗
PubMed1993

Multicentre survey of the comparative in-vitro activity of piperacillin/tazobactam against bacteria from hospitalized patients in the British Isles.

Twenty-nine British and Irish hospitals each collected up to 300 bacterial isolates from in-patients. The organisms were identified by an appropriate API system or, for staphylococci, by their Gram and coagulase reactions. Disc susceptibility tests were performed. Isolates that gave zones < or = 25 mm to piperacillin/tazobactam (75 micrograms + 10 micrograms) discs were sent to a central laboratory for re-examination and determination of MIC, together with a sample of the more susceptible organisms. Results were evaluated for 6724 isolates. Over 95% of the isolates of Escherichia coli, klebsiellae, Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus, Moraxella and Bacteriodes, spp. streptococci, pneumococci and Enterococcus faecalis were susceptible to piperacillin/tazobactam (defined as giving a zone > or = 22 mm to a 75 micrograms + 10 micrograms disc), as were 86% of Acinetobacter spp. and 82% of the Citrobacter, Enterobacter, Morganella and Serratia group. Tazobactam particularly extended the activity of piperacillin against E. coli isolates (96% susceptible cf. 61% to piperacillin alone) klebsiellae (95% cf. 70%), P. mirabilis (99% cf. 86%), and Acinetobacter spp. (86% cf. 53%). Occasional (18%) resistance in Enterobacter, Serratia and Citrobacger spp. was probably caused by stable depression of Class I beta-lactamases, which are inhibited poorly by tazobactam. High resistance frequencies (> 25%) were found for Enterococcus faecium and Xanthomonas maltophilia. Tazobactam potentiated piperacillin against beta-lactamase-producing methicillin-susceptible Staphylococcus aureus, but the mode inhibition zone of piperacillin/tazobactam discs was only 26 mm, compared to 38 mm for beta-lactamase-negative isolates. Nevertheless, fewer than 5% of the enzyme producers appeared resistant to 8 + 4 mg/L piperacillin/tazobactam in MIC tests. Similar behaviour was noted for coagulase-negative staphylococci. Amongst the eleven comparator drugs, ceftazidime, gentamicin and ciprofloxacin were as active as piperacillin/tazobactam against most enterobacteria. However, Acinetobacter and Bacteroides spp. and enterococci were resistant to ceftazidime, and Bacteroides spp., enterococci, pneumococci and other streptococci were inherently resistant to ciprofloxacin and gentamicin. Cefuroxime, ampicillin and co-amoxiclav had narrower spectra. Only imipenem showed a consistently wider spectrum and lower frequency of resistance than piperacillin/tazobactam.

Bacteria, Anaerobic↗
PubMed1993

Wellness: the dialectic of illness.

From a review of empirical and theoretical work, a model of wellness-illness evolved. The unfolding of events associated with wellness-illness is depicted as a generic paradigm with health, disease, wellness and illness existing in a dialectical relationship. Although distinct, health-disease and wellness-illness are neither mutually exclusive nor polar opposites. Rather, they are one in the same process, acknowledging the changing person in the changing world. Wellness-illness is the human experience of actual or perceived function-dysfunction through the interaction of cognitive-affective dimensions. This experience arises out of intrapersonal, interpersonal, health-disease-related and extra-personal factors.

Disease↗
PubMed1993

Evaluation of whiplash injuries by technetium 99m isotope scanning.

Despite the frequency with which whiplash injuries present to accident and emergency (A&E) departments, there lacks an objective investigation to define the severity of the initial injury or the morbidity that may ensue. Following reports on the effectiveness of isotope bone scanning for soft tissue and ligament injuries a study was undertaken of isotope scanning of whiplash injuries. The objectives of the study were to isolate the anatomic site of the injury and to quantify the severity of the injury with relation to the concentration of isotope uptake and subsequent morbidity.

Adolescent↗
PubMed1993

Use of psychopathology vignettes by patients with schizophrenia or schizoaffective disorder and by mental health professionals to judge patients' insight.

OBJECTIVE: The goal of this study was to clarify more precisely where patients with psychotic disorders and the mental health professionals who care for them disagree regarding whether the patient is ill or needs treatment. METHOD: The authors prepared brief vignettes in everyday descriptive language that provided examples of the classical positive and negative psychopathological features of schizophrenia. Fifteen men and 11 women diagnosed as having schizophrenia or schizoaffective disorder and one physician used these vignettes as a common frame of reference to rate 1) the degree to which the patients demonstrated the features described in each vignette and 2) the degree to which the features signified the presence of mental illness. RESULTS: Disagreements between the physician's and patients' ratings, indicating deficits in insight, were associated with the recognition of the presence of conceptual disorganization, avolition-apathy, and affective blunting in the patients by the physician but not the patients and with the conceptualization of hallucinatory behavior and suspiciousness as signs of mental illness by the physician but not the patients. CONCLUSIONS: The authors conclude that the failure to acknowledge conceptual disorganization, avolition-apathy, and affective blunting and the failure to view hallucinatory behavior and suspiciousness as signs of mental illness, which proved to be additive in this study, contribute to deficits in insight.

Adult↗
PubMed1993

Submucous resection: is it a simple procedure?

With the need to cut costs in the health care system, there has been a rapid increase in the number of surgical procedures performed on an outpatient basis. It is therefore important that patients have enough information to enable them to cope at home. To determine the informational needs of patients undergoing several surgical procedures and examine their postoperative course, a telephone survey was conducted. The results from one group, those undergoing a submucous resection (SMR), stood out. When compared with the 292 patients in the overall study, the 33 SMR patients complained of considerably more discomfort, tiredness, and nausea. Sixty percent of these patients were not satisfied with the information they received. Most would have liked more information about how they would feel postoperatively and how they could cope with their various concerns and problems. The teaching materials and approach to postoperative care for these patients may need to be altered.

Adult↗
PubMed1993

AccuMeter noninstrumented quantitative assay of high-density lipoprotein in whole blood.

A novel noninstrumented technology (ChemTrak AccuMeter) for the quantitative measurement of analytes in biological fluids was reported at the 1990 Oak Ridge Conference (Clin Chem 1990;36:1591-7). This instrument-free technology has been adapted for the quantitative measurement of high-density lipoprotein (HDL). An in situ lipoprotein separation method has been developed and incorporated into the test for HDL determination. The sensitivity of the assay system has been adjusted so that HDL is measured over a clinically significant range of 250 to 1000 mg/L. This compares to a range of 1000 to 4000 mg/L for the total cholesterol in the earlier reported assay. Like the AccuMeter total cholesterol test, the Accumeter HDL test system is self-contained and consolidates blood separation, lipoprotein separation, and specimen measurement into a single step. The test procedure is simple, and the results are accurate.

Blood Chemical Analysis↗
PubMed1993

A clinical study monitoring low-intensity anticoagulant therapy with a standard-sensitivity thromboplastin.

The ability of the prothrombin time to measure the anticoagulant effect of warfarin sodium varies depending on the particular tissue thromboplastin used in performing the test. Based on studies using sensitive thromboplastins, lower therapeutic ranges of anticoagulation are recommended. The adequacy of monitoring therapy in this lower range with the relatively insensitive thromboplastins commonly used in North America is unestablished. This 16-month prospective study used a standard North American thromboplastin to monitor 157 anticoagulated patients treated in a low therapeutic range. Of the 1734 prothrombin times generated, 876 (56%) were therapeutic, with 400 (23%) below and 458 (26%) above the therapeutic range. These results are comparable with those published in trials in which more sensitive thromboplastins were used in a similar therapeutic range. We conclude that standard North American thromboplastins are adequately suited to monitor therapy in this lower range.

Aged↗
PubMed1993

Genetic typing of HLA class II genes in Swedish populations: application to forensic analysis.

In an attempt to determine the value of DNA based typing of HLA class II loci to forensic analysis, allele and genotype frequencies at DQA1, DQB1, DPB1, and DRB1 were determined in samples from two Swedish populations using hybridization with sequence specific oligonucleotides to PCR amplified DNA. Significant allele frequency differences were observed at the DQB1 and DRB1 loci between the two populations, as well as between one of the Swedish and a Norwegian population. The average heterozygosity varies between 0.74 to 0.91 and the power of discrimination between 0.90 to 0.98, with the highest values obtained for the DRB1 locus. The probability of genotype identity by chance differs on average 2% between the populations. When applied to a paternity case with one parent deceased and a criminal case, typing of class II loci proved in both cases informative. Analyses of DR and DQ genes does not increase the power of discrimination, due to strong linkage, but offers through the reconstruction of putative haplotypes an internal control for the consistency of the typing results at several loci. Typing of the DRB1 and DPB1 loci was found to result in an approximate combined average probability of genotype identity by chance of one in a thousand.

Alleles↗
PubMed1992

Solar control of the upper atmosphere of Triton.

If the upper atmosphere and ionosphere of Triton are controlled by precipitation of electrons from Neptune's magnetosphere as previously proposed, Triton could have the only ionosphere in the solar system not controlled by solar radiation. However, a new model of Triton's atmosphere, in which only solar radiation is present, predicts a large column of carbon atoms. With an assumed, but reasonable, rate of charge transfer between N2(+) and C, a peak C+ abundance results that is close to the peak electron densities measured by Voyager in Triton's ionosphere. These results suggest that Triton's upper atmospheric chemistry may thus be solar-controlled. Measurement of key reaction rate constants, currently unknown or highly uncertain at Triton's low temperatures, would help to clarify the chemical and physical processes occurring in Triton's atmosphere.

Atmosphere↗