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Biomedical subjects

M A Roberts

Publications and source records attributed to M A Roberts.

At least 19 recordsLinked to original sources
PubMed1992

Genetic variation in the African rodent subfamily Otomyinae (Muridae). II. Chromosomal changes in some populations of Otomys irroratus.

Chromosome-banding studies have been carried out on 31 specimens of Otomys irroratus from six localities. Light-microscope preparations of chromosomes were obtained from cultures of fibroblasts, spleen lymphocytes, peripheral blood lymphocytes, and directly from bone marrow. Karyotypic variability, both numerical and morphological, was detected in three populations. Diploid numbers ranged from 2n = 23 to 2n = 32. Intrapopulation differences were chiefly caused by variation in the number of copies in two pairs of small, biarmed, partly heterochromatic autosomes suggestive of B chromosomes. A major morphological variation in the karyotypes involved the presence of seven pairs of biarmed autosomes with totally heterochromatic short arms in the populations distributed to the west of 26 degrees 57' E. To the east of this longitude, populations of this species exhibited mostly acrocentric autosomes. G-banding patterns of these karyotypes and those of a karyotype from a previous study (Robinson and Elder, 1987) were compared. A chromosome originating from a tandem fusion, possibly leading to partial reproductive isolation, was found in one population. Possible implications of these results for mechanisms of speciation are discussed.

Animals↗
PubMed1992

The roles of general and geriatric medicine in the provision of acute medical care for elderly patients.

To determine whether there are differences between elderly patients admitted acutely to general medicine and those admitted to geriatric medical wards, and whether the patients are appropriately referred, a prospective survey of 426 consecutive patients aged 65 years or over admitted acutely to general medical and geriatric wards over a three month period was performed. A total of 286 patients were admitted to general medicine (GM) and 140 to the geriatric unit (GER). GER patients were older (81.0 v. 75.8 years) and had greater pre-morbid functional impairment and incontinence. Fewer GER patients presented with readily apparent organ specific diagnoses (56% v. 94%). Median length of stay was longer in GER patients (23 days v. 9 days). Variables independently predictive of GER admission were increasing age, increasing duration of illness, poor pre-morbid functional status and prior reliance on a carer. Length of stay was not associated with unit of admission allowing for the variables described above. GER patients are a different population. They have more chronic illness and functional impairment, and are more likely to require multidisciplinary assessment and rehabilitation in addition to treatment of presenting illness. Elderly patients are appropriately referred by General Practitioners (GPs) without a formal admissions policy.

Aged↗
PubMed1991

Immunologic relatedness of extracellular ligninases from the actinomycetes Streptomyces viridosporus T7A and Streptomyces badius 252.

Four isoforms of the extracellular lignin peroxidase of the ligninolytic actinomycete Streptomyces viridosporus T7A (ALip-P1, P2, P3, and P4) were individually purified by ultrafiltration and ammonium sulfate precipitation, followed by electro-elution using polyacrylamide gel electrophoresis. Three of the purified peroxidases were compared for their immunologic relatedness by Western blot analysis using a polyclonal antibody preparation produced in rabbits against pure isoform P3. The anti-P3 antibody was also tested for its reactivity towards a lignin peroxidase from the white-rot fungus Phanerochaete chrysosporium and another ligninolytic actinomycete Streptomyces badius 252. Results showed that peroxidases ALip-P1 through ALip-P3 are immunologically related to one another. The peroxidases of S. badius, but not the peroxidase of P. chrysosporium, also reacted with the antibody, thus indicating that the lignin peroxidases of S. viridosporus and S. badius are immunologically related. Based upon its specific affinity, lignin peroxidase isoform ALip-P3 of S. viridosporus was readily purified using an anti-P3 antibody affinity column.

Blotting, Western↗
PubMed1990

A behavioral observation method for differentiating hyperactive and aggressive boys.

This study employed a playroom observation technique to examine the behavioral differences between hyperactive and aggressive boys. Subjects were clinic-referred boys assigned to Hyperactive, Aggressive, or Hyperactive plus Aggressive groups on the basis of behavior checklists and ratings of psychiatric chart information. While significant discrimination was obtained in all three settings (free play, restricted play, and restricted academic), behavioral differences among the subject groups were most pronounced during the restricted academic period. Discriminant function analysis for the restricted academic period resulted in accurate classification of 86% of the subjects as hyperactive, aggressive, or hyperactive plus aggressive. The present findings suggest that children with externalizing disorders can be distinguished in light of their observed clinic behavior in the restricted academic setting.

Aggression↗
PubMed1990

Axonal guidance of adenosine deaminase immunoreactive primary afferent fibers in developing mouse spinal cord.

This study examined the precision of central fiber growth in a subpopulation of dorsal root ganglion neurons in developing mouse spinal cord. Immunohistochemical techniques using a monospecific, polyclonal antiserum to mouse adenosine deaminase (ADA) were utilized to label a population of primary sensory afferents that have been found to exclusively innervate laminae I and II of the dorsal horn in adult mice. Initial growth of ADA-immunoreactive (ADA-IR) primary afferents occurred very early in development, embryonic day 10 (E10), a time coincident with the earliest settling time of dorsal root ganglion neurons. Adenosine deaminase immunoreactive primary afferents were observed throughout the cross-sectional area of the primordial dorsal funiculus (DF) as early as E10. Immunostained fibers remained quiescent in the DF during its growth and separation into the tract of Lissauer and dorsal column pathway. By E15, the two pathways had formed and ADA-IR fibers were observed exclusively in the tract of Lissauer. This segregation of fibers remained throughout development and reflected the adult pattern. Growth was reinitiated at E16 when the fibers advanced into the dorsal horn and proceeded directly to laminae I and II mimicking their adult distribution. Exuberant fiber growth was not detected throughout their development. These results strongly suggest that ADA-IR fibers exhibit precise fiber guidance to a preferred pathway, the tract of Lissauer, and accurate laminar innervation of the dorsal horn.

Adenosine Deaminase↗
PubMed1990

The contribution of computerized tomography to the differential diagnosis of confusion in elderly patients.

Two hundred and eighty elderly patients who were referred because of a principal problem of confusion were investigated by computerized tomography; 94% were suffering from a 'dementia syndrome' and unrecognized receptive dysphasia was the commonest problem in the remainder. One hundred and twenty-four patients were suffering from senile dementia of the Alzheimer type, and 79 from multi-infarct dementia. Space-occupying lesions (tumour, subdural haematoma or hygroma) were found in 32 (11%). Of the 25 with other intracranial and extracranial causes, 64% had potentially treatable lesions (PTL). In only four cases was no diagnosis made. PTL were found in 31% of 170 patients with a duration of confusion of less than a year compared with 1% of 110 patients with a longer duration. In 48 of the former group, confusion was an isolated phenomenon; 12 of these (25%) had a PTL, as had 27 of 88 with confusion and a focal neurological deficit (31%). All five patients with recognized seizures, and six of 15 of those with reduced alertness had PTL. Twenty of 37 patients with neurosurgical lesions underwent surgery.

Aged↗
PubMed1989

A prospective audit of the use and costs of myelography in a regional neuroscience unit.

A consecutive series of 397 myelograms performed in 385 patients over a six month period at the Mersey Regional Neurosciences Unit is reported. The reasons for performing the myelogram were to identify the cause of a radicular lesion in 54% of patients, a chronic spinal cord lesion in 30%, an acute cord lesion in 9%, suspected disease at the level of the foramen magnum 6%, and for a variety of other conditions in 8%. For the 385 patients undergoing a myelogram in the study period, the median interval from admission to request, request to myelography and from myelography to discharge was nought, one and three days respectively. The proportion of patients submitted to myelography by individual consultants ranged from 7% to 28%. There was a two-fold variation in the delays in the time to requesting and performing myelograms. There was room for improvement in the clinical information supplied on the myelography request form. The role of ancillary investigations and their effect on myelography was unclear. Only 16 of the patients with suspected cord disease had visual evoked responses performed before myelography. Five of them had myelography after an abnormal result. The estimated annual direct cost of myelography in the unit was at least 486,000 pounds. Reorganisation might have yielded hypothetical "savings" of between 30,000 pounds (6%) and 155,000 pounds (32%), though in practical terms these "savings" represented resources which might have been freed for use in other higher priority clinical problems within the unit, rather than true reductions in monetary cost.

Myelography↗
PubMed1988

High-risk factors for cervical cancer. An epidemiological study in SWA/Namibia.

In an epidemiological study conducted in SWA/Namibia to document the prevalence of high-risk factors for cervical cancer 754 women belonging to a number of ethnic groups were examined. The prevalence of cervical intra-epithelial neoplasia and human papillomavirus infection was among the highest reported in the world. There was also an alarming incidence of other sexually transmitted diseases and disturbingly low usage of contraceptive methods. There is an urgent need for a comprehensive, well-organised cytological screening programme if an 'epidemic' of cervical cancer is to be prevented in SWA/Namibia. There was good evidence to suggest that an identical situation exists in the RSA.

Adult↗
PubMed1986

Pyrexia in infection in the elderly.

This prospective study investigated the common belief that pyrexia is frequently absent in elderly patients with infection. Oral temperature was closely monitored using both a mercury and an electronic thermometer in 150 ill elderly patients (mean age 81 years) of whom 80% were new admissions to this Unit. A scoring system was devised, based on investigation results and excluding temperature, to assess objectively the likelihood of infection. Seventy-one patients (47%) had 'definite' infection: 95% were pyrexial. A further eight of the nine patients with probable infection were pyrexial. There were no significant differences in mean temperature or other indices of infection between those who died of their infection and those who survived. Ten per cent of all pyrexias were detected only on the electronic thermometer, not on mercury measurement. In 12% of pyrexial patients, the pyrexia first appeared more than 12 h after temperature measurement started. With effective monitoring, pyrexia is detectable in the vast majority of infected elderly patients.

Age Factors↗
PubMed1985

Comparative evaluation of commercial rubella virus antibody kits.

Comparative evaluation of six commercial rubella virus antibody kits is described. A set of serum samples skewed toward nonreactive and low-positive rubella antibody levels was used because the goal of an immunity screening test is the detection of susceptible individuals. The M. A. Bioproducts Rubastat and the Hynson, Westcott and Dunning Rubascan were superior in achieving high sensitivity, specificity, and reproducibility. They also were the easiest and fastest tests to perform, and they require equipment available in most laboratories.

Antibodies, Viral↗
PubMed1985

Normal pressure hydrocephalus and Paget's disease of bone.

Although senile dementia of Alzheimer type (SDAT) is the commonest cause of dementia in the elderly, it is important to recognise potentially reversible causes such as normal pressure hydrocephalus. This has been reported to occur in association with Paget's disease of the skull, but would appear to be an extremely rare complication of this disease. To date 4 cases of successful surgical intervention in normal pressure hydrocephalus complicating Paget's disease of skull have been reported. We report 3 cases which have presented to one Department of Geriatric Medicine during a 3-year period. Two cases were diagnosed prior to death and both responded well to ventriculo-peritoneal shunting.

Aged↗
PubMed1978

Endogenous prostaglandin synthesis inhibitor in the renal cortex. Effects on production of prostacyclin by renal blood vessels.

1. The capacity of various tissues of the porcine kidney to convert [1-14C]arachidonic acid into radiolabelled prostaglandins was studied. 2. Only after removal from the cortical matrix, were renal blood vessels able to convert arachidonic acid into prostaglandins (primarily prostacyclin). In contrast, convoluted tubules showed a low capacity to metabolize arachidonic acid. 3. The failure to demonstrate prostaglandin synthesis by renal cortical slices is related to the presence of an inhibitor of cyclo-oxygenase. Thus the addition of renal cortical incubate to isolated vascular tissues and ram seminal vesicles inhibited their ability to synthesize prostaglandins. 4. Slices of renal medulla metabolized arachidonic acid primarily to prostaglandin F2alpha; lesser amounts of prostaglandin E2 and prostacyclin were generated. 5. The large capacity of the renal vasculature to generate prostacyclin is consistent with an important role for this prostaglandin in regulation of renin release and renal haemodynamics.

Animals↗