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Biomedical subjects

M A Roberts

Publications and source records attributed to M A Roberts.

At least 55 records · Page 3Linked to original sources
PubMed1996

Assessing olfaction following pediatric traumatic brain injury.

A brief procedure for screening the olfactory function in elementary-age children was developed in the present investigation When the performance of pediatric patients with mild traumatic brain injury (TBI) was compared with that of a matched sample with severe TBI, the severe TBI sample was one and one-half times as likely to exhibit an impaired sense of smell of formal testing (p<0 05) Subsequent analyses demonstrated that patients with olfactory deficits were three times as likely to manifest executive dysfunction as reported by their parents on a behavior rating scale In contrast to formal testing, individual interview revealed that TBI subjects and their parents were seldom aware of olfactory deficits Thus, formal testing of olfaction following pediatric head trauma should not be deferred.

Journal Article↗
PubMed1996

The prevalence of joint contractures in residents in NHS continuing care.

A group of 222 residents in NHS continuing care were studied in order to assess the prevalence of joint contractures in the very disabled elderly and to establish whether there was an association between the presence of contractures and functional ability; 121 (55%) had at least one contracted joint. There was no clear linear relationship between length of stay in continuing care and the presence of contractures. Those with upper limb contractures were nearly twice as likely to be unable to feed themselves as those without contractures (p < 0.0001). The presence of at least one lower limb contracture was significantly associated with reduced mobility (p < 0.0001). An association was also demonstrated between the presence of lower limb contractures and frequency with which the patient walked. The role of disease and immobility in the development of contractures is discussed as well as the potential for the prevention and treatment of contractures.

Activities of Daily Living↗
PubMed1995

Investigation of liposome-based immunomigration sensors for the detection of polychlorinated biphenyls.

The use of immunospecific liposome migration offers many advantages for the extralaboratory detection of environmental contaminants. Devices utilizing this technique are fast, easy to use, and robust and respond to the presence of analyte at low-parts-per-billion concentrations. Investigations have been carried out that determine optimal interactions for key components of these assays, and techniques are presented for the development of generalized liposome immunoassays. Two complementary prototype liposome-based immunomigration techniques have been developed for the detection of polychlorinated biphenyls (PCBs). The liposome immunocompetition assay format measures the competitive reaction between analyte-tagged liposomes and the sample analyte for immobilized antibodies and can detect 0.4 nmol of PCB in less than 8 min. A more sensitive format, the liposome immunoaggregation (LIA) assay detects the inhibition of immunospecific liposome aggregation in solution and can detect 2.6 pmol of PCB in less than 23 min. Laser diffraction particle sizing has been used to study LIA-induced increases in liposome size over time and to determine optimal conditions for the application of this technique. Both formats utilize capillary action to transport liposome-containing solutions along strips of nitrocellulose. Measurement of color intensity is then carried out visually or with a desktop scanner.

Animals↗
PubMed1995

External validation of oppositional disorder and attention deficit disorder with hyperactivity.

Validity of the distinction between oppositional disorder (OD) and attention deficit disorder with hyperactivity (ADDH) was examined in a sample of 6- to 12-year-old boys with behavior problems. Problem identification, cognitive/attentional, family context, and behavioral symptom differences were examined among nine boys with OD only, 20 with ADDH, 40 with comorbid OD and ADDH, and 28 with neither disruptive behavior disorder. Systematic comparisons of groups including and excluding the OD and ADDH diagnoses were undertaken to determine the existence of pure OD and pure ADDH disorder effects. The most consistent result was the lack of evidence for either pure OD or pure ADDH effects. Most of the significant findings reflected differences between the nondisruptive (neither) and comorbid groups. The results support the importance of comorbidity, but they provide little support for disorder-specific distinctions between oppositional and attention deficit disorders.

Attention Deficit Disorder with Hyperactivity↗
PubMed1995

Energy intake and expenditure in elderly patients admitted to hospital with acute illness.

Studies on hospitalized elderly subjects have demonstrated that negative energy balance is common during hospitalization, but have concentrated primarily on long-stay and psychogeriatric patients. There is little information on energy balance in elderly patients admitted with acute illness from the community, despite the importance of this patient group and the presence of a number of factors likely to predispose such patients to negative energy balance. In the present study energy balance was quantified in twenty patients (eight males, mean age 82 (SD 5) years; twelve females, mean age 84 (SD 6) years) admitted from the community with acute illness, and predicted basal metabolic rate (BMR) was compared with measured resting metabolic rate (RMR). Most patients were in negative energy balance during hospitalization, and median measured energy intake (EI): measured RMR ratio was 1.0 (range 0.7-1.8). The mean difference between measured EI and estimated total energy expenditure was -1.3 MJ/d (range -3.4 to +2.5 MJ/d). Estimated total energy expenditure exceeded measured EI in fifteen of the patients and there was a significant decline in mid-arm muscle circumference (paired t, P < 0.05) during hospitalization. We conclude that moderate negative energy balance is common in this patient group, and that these patients are at risk of undernutrition during their hospital stay.

Acute Disease↗
PubMed1995

Neurobehavioural dysfunction following mild traumatic brain injury in childhood: a case report with positive findings on positron emission tomography (PET).

The present case study describes the neurobehavioural, neurodiagnostic, and positron emission tomography (PET) scan findings in a child who sustained a whiplash-type injury in a motor vehicle accident. Although neck and back pain were reported immediately, neurobehavioural symptoms, such as staring spells, gradually increased in frequency over a 2-year period following the accident. At 4 years after the accident the patient's symptoms persisted, as reported by teachers and parents, and more extensive diagnostic work-up was initiated. Standard EEG was normal while two ambulatory EEGs were abnormal and interpreted as epileptiform. A PET scan showed evidence of marked hypometabolism in both temporal lobes. Neuropsychological findings were consistent with PET findings and reflected verbal and visual memory deficits in the context of high average intelligence. Treatment with carbamazepine, verapamil, and fluoxetine greatly improved the patient's symptoms. The present case illustrates an example of a poor outcome in a paediatric case of mild traumatic brain injury, the importance of PET in demonstrating definitive evidence of brain dysfunction, and the child's positive response to anticonvulsant medication.

Accidents, Traffic↗
PubMed1994

Structure of malhamensilipin A, an inhibitor of protein tyrosine kinase, from the cultured chrysophyte Poterioochromonas malhamensis.

A new chlorosulfolipid, malhamensilpin A [1] was isolated from the cultured chrysophyte Poterioochromonas malhamensis. Malhamensilipin A was demonstrated to be a modest inhibitor of pp60v-src protein tyrosine kinase. The structure was determined by detailed spectral analysis to be a novel C24 hexachloro lipid containing a vinyl sulfate ester (2,11,12,13,15,16-hexachloro-14-hydroxy-n-tetracos-1E-enol-1-sulfa te).

Bacteria↗
PubMed1994

Yet another short-form of the Wechsler scales for use in neuropsychological assessment.

The general purpose of the present study was to make Hamsher's seven subtest short-form of the WAIS-R (or WAIS) more accessible to neuropsychologists. Formulas are presented for both instruments which permit calculation of Verbal-Conceptual, Attention-Concentration, Perceptual-Organizational, and Full Scale deviation quotients. Results from two samples of psychiatric patients suggest that this abbreviated approach to using the Wechsler IQ batteries provides reasonably accurate estimates of traditional IQ scores. A case example illustrates how analysis of the various deviation quotients can contribute to neuropsychological reasoning at the level of the individual patient.

Journal Article↗
PubMed1994

The Dichotic Word Listening Test: preliminary observations in American and Canadian samples.

The present article describes observations of 670 American and Canadian child and adult control subjects on the recently developed Dichotic Word Listening Test (DWLT). The task was also administered to a sample of American children with traumatic brain injuries (n=21) of varying severity and a sample of American adults with mild traumatic injuries (n=36). The conceptual focus in this line of research was on using normative observations to identify clinically defective channels of auditory processing among patients. The principal findings were as follow: 1) the DWLT was sensitive to the effects of cerebral dysfunction following traumatic brain injury; 2) differences among normal samples with different demographic backgrounds were frequently observed, arguing for the development of local norms; 3) a shorter form of the DWLT task (DWLT30) can be used for screening purposes with relatively little reduction in sensitivity to cerebral dysfunction; 4) there appeared to be considerable improvement of DWLT performance between the ages of five and seven, due largely to higher scores from the left auditory channel; and 5) there were indications that use of French (rather than English) as one's native language before age six can negatively influence performance in adulthood on an English version of the DWLT. In general, the present findings suggest that the DWLT is likely to have relatively broad applicability for neuropsychological assessment across the life-span.

Journal Article↗
PubMed1994

Outbreaks of syphilis in rural Texas towns, 1991-1992.

Between 1986 and 1990, rates of primary and secondary syphilis increased 134% in rural counties in the South. Reasons for the increases are speculative. During the 14 months ending in October 1992, outbreaks in four eastern Texas counties provided an opportunity to characterize syphilis in rural Texas. We reviewed records for 118 patients and 339 sex partners. Three outbreaks were concentrated in neighborhoods where crack cocaine dealers conducted business and exchange of sex for drugs or money was common; the fourth outbreak involved out-of-town prostitutes who visited undocumented alien workers. Among the 118 syphilis cases, 15 (13%) were primary, 35 (30%) were secondary. Most patients were black (105, 89%); the male-female ratio was 1:1. One woman gave birth to an infant with congenital syphilis. Almost half of the sex partners were infected. HIV pretest counseling was completed for only 55 patients (47%), and only 23 (19%) were tested for the human immunodeficiency virus. These four rural outbreaks of syphilis associated with crack cocaine and the exchange of sex for drugs or money mirror recent urban syphilis outbreaks. Patients in these rural syphilis outbreaks are at risk for HIV infection, but HIV testing has not been emphasized by public health workers.

Adult↗
PubMed1994

The diurnal variation of stroke in Ghana.

In 68 patients presenting with stroke in Ghana a significant (P < 0.001) peak in onsets occurred between 0600 h and 1000 h. There were no significant differences in time of onset between men and women or hypertensive and non-hypertensive patients. Reasons for the peak of onsets are discussed. A similar diurnal pattern of stroke has been described in temperate countries: any benefits such as timing of prophylactic measures that ensue from research on stroke in temperate climates are likely to be of benefit if also applied to those at risk of stroke in a tropical climate.

Adult↗
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↗