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T Robinson

Publications and source records attributed to T Robinson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Mapping tsetse habitat suitability in the common fly belt of southern Africa using multivariate analysis of climate and remotely sensed vegetation data.

The distribution of Glossina morsitans centralis, Glossina morsitans morsitans and Glossina pallidipes are described in part of southern Africa, using a range of multivariate techniques applied to climate and remotely sensed vegetation data. Linear discriminant analysis is limited in its predictive power by the assumption of common covariances in the classes within multivariate environment space. Maximum likelihood classification is one of a variety of alternative methods that do not have this constraint, and produce a better prediction, particularly when a priori probabilities of presence and absence are taken into account. The best predictions are obtained when the habitat is subdivided, prior to classification, on the basis of a bimodality detected on the third component axis of a principal component analysis. The results of the predictions were good, particularly for G.m.centralis and G.m.morsitans, which gave overall correct predictions of 92.8% and 85.1%, with a Kappa index of agreement between the prediction and the training data of 0.7305 and 0.641 respectively. For G.pallidipes, 91.7% of predictions were correct but the value of Kappa was only 0.549. Very clear differences are demonstrated between the habitats of the two subspecies G.m.centralis and G.m.morsitans.

Africa, Southern↗
PubMed1997

Cardiopulmonary and arterial baroreflex-mediated control of forearm vasomotor tone is impaired after acute stroke.

BACKGROUND AND PURPOSE: Elevated blood pressure (BP) levels are well recognized after acute stroke and are associated with increased BP variability. The underlying mechanisms producing such changes are unclear but may include abnormalities of baroreceptor-mediated control of heart rate and vasomotor tone. Lower body negative pressure (LBNP) can be used to assess the integrity of "low-pressure" cardiopulmonary and "high-pressure" arterial baroreceptor-derived responses by inducing nonhypotensive and hypotensive stimuli. METHODS: Cardiovascular responses, including BP, heart rate, forearm blood flow, and forearm vascular resistance, to nonhypotensive and hypotensive LBNP were assessed in 13 consecutive stroke patients. Patients were studied within 72 hours of stroke (acute) and again at 10 to 14 days (subacute) and were compared with 13 control subjects individually matched for age, sex, and BP. RESULTS: At an LBNP of -10 mm Hg, BP was unchanged in all groups, but a significant increase in forearm vascular resistance occurred only in the control group (11 U [interquartile range, 7 to 15]; P < .05) compared with stroke patients in the acute (9 U [3 to 14]; P = NS) or subacute phases (7 U [2 to 12]; P = NS). After LBNP at -40 mm Hg, the reductions in systolic BP levels were similar in all groups (control: -9 mm Hg [-16 to -3]; acute stroke: -9 mm Hg [-22 to 3]; subacute stroke: -7 mm Hg [-35 to 20]), as was the associated increase in heart rate (control: 8 bpm ([4 to 11]; acute stroke: 6 bpm ([1 to 12]; subacute stroke: 9 bpm [2 to 19]). However, forearm vascular resistance increased significantly only in control subjects (20 U [9 to 30]; P < .01). CONCLUSIONS: The present study has identified abnormal vasomotor responses to LBNP after acute stroke, with an increase in FVR only being observed in control subjects in response to nonhypotensive and similar hypotensive levels of LBNP. In acute stroke patients, the stimulus of hypotensive LBNP appears to be compensated by an increase in cardiac output since there appears to be no increase in peripheral vascular resistance, unlike the changes seen in control subjects. However, the exact mechanisms for these changes are still unclear and are the subject of further study.

Acute Disease↗
PubMed1996

Neuropsychological, olfactory, and hygiene deficits in men with negative symptom schizophrenia.

Associations between symptom subtypes, life skills, olfactory identification, and neuropsychological ability were investigated in patients with schizophrenia and related to observations of poor personal hygiene and implied functional compromise of orbitofrontal integrity. Twenty-seven men with chronic schizophrenia were assessed using the Positive and Negative Syndrome Scale for Schizophrenia and the Life Skills Profile. Performance on the University of Pennsylvania Smell Identification Test (UPSIT), the Modified Wisconsin Card Sorting Test (MWCST), delayed response/alternation, and memory tasks derived from the Wechsler Memory Scale-Revised (WMS-R) was also compared to that of an age-, sex-, and IQ-matched control group. Patient UPSIT, MWCST, and WMS-R performance was significantly impaired in comparison to controls. Poor UPSIT performance and poor self-care were significantly associated with negative symptoms. Also, UPSIT ability was associated with performance on the MWCST in both patients and controls, whereas an association with performance on the WMS-R was only found in normal subjects rather than in the patients with schizophrenia. The importance of these findings to postulated mechanisms involving prefrontal rather than mediotemporal lobe (MTL) function in schizophrenia are discussed, as is the relevance of the use of smell identification ability to subtype identification and rehabilitative strategies.

Activities of Daily Living↗
PubMed1996

Challenges with Takayasu's arteritis: a case study.

Takayasu's arteritis (TA) is a systemic vasculitis that involves an autoimmune-mediated transmural degeneration of the aorta and its major branches, leading to severe arterial stenoses or occlusions with subsequent cerebral, cardiopulmonary, mesenteric, renal, or limb ischemia. Patient history and physical examination, arteriography, magnetic resonance imaging, and specific laboratory tests facilitate the diagnosis of TA. Major treatments for the condition include the use of corticosteroids, cytotoxic agents, antiplatelet drugs, percutaneous transluminal angioplasty (PTA), and surgical revascularization. Major nursing interventions for TA include teaching the patient and family about the progression and treatments of TA and performing periodic patient assessments for manifestations of systemic vasculitis, alterations in tissue perfusion, and alterations in coping.

Adult↗
PubMed1996

Euthanasia on trial: examining public attitudes toward non-physician-assisted death.

This study investigated the influence of various contextual effects on the decisions of subjects evaluating a case of nonphysician-assisted suicide. Subjects viewed a videotaped deposition of an individual emotionally or nonemotionally describing how he assisted in the death of his terminally ill wife by disconnecting her respirator or shooting her in the head. The deposition was followed by jury instructions that outlined the duties of the subject and, in some cases, was followed by a nullification instruction that informed the subjects of their right to ignore the law in this case if they felt it would culminate in an unfair verdict. After viewing the videotape, subjects were asked to rate the guilt of the individual as well as their confidence in this rating. Results indicate that the means of death and the type of instruction significantly affect guilt ratings. The implications of these findings are discussed.

Adult↗
PubMed1996

Comparative pathogenesis of human WA1 and Babesia microti isolates in a Syrian hamster model.

The pathogenesis of a newly recognized, molecularly and antigenically distinct human babesial isolate (WA1) and Babesia microti, the common cause of human babesiosis in the United States, were compared in a Syrian hamster model. A group of 33 adult female hamsters were inoculated intraperitoneally with either WA1-infected, B. microti-infected, or uninfected hamster erythrocytes. All WA1-infected animals became parasitemic by postinoculation (PI) day 3 or 4 and were severely lethargic and dyspneic by PI days 6 to 10. Death often occurred spontaneously by PI day 10, with parasitemia of 12 to 90%. Hamsters inoculated with B. microti became parasitemic by PI day 7 and developed peak parasitemia (42 to 60%) by PI day 14 that subsequently decreased to low or undetectable values. Although the B. microti-infected hamsters developed severe anemia, they generally remained asymptomatic. Postmortem examination of WA1-infected hamsters revealed intravascular aggregates of large mononuclear inflammatory cells that occasionally occluded small to medium veins, pulmonary leukoclastic phlebitis, thrombosis, and multifocal coagulative necrosis in the heart, spleen, lung, and liver. No vascular lesions or areas of coagulative necrosis were detected in any B. microti-infected or control hamsters. The results of this study suggest that marked leukocytosis followed by acute necrotizing phlebitis resulting in disseminated intravascular coagulation, thromboembolism, and infarction may be central to the pathogenesis of WA1 infections.

Anemia↗
PubMed1996

Neuropsychiatric lupus and hormones.

Neuropsychiatric lupus can present with a broad spectrum of severity, ranging from mild chronic symptomatology to acute life threatening illness. There are no accepted diagnostic or classification criteria, but most agree that the manifestations can be described as representing diffuse CNS insult or a more focal or localized process. The pathogenesis is unknown, but it is likely that there is more than one mechanism given the heterogeneous clinical presentations. It is probable that autoantibody formation, vascular injury, and cytokine production all play a role. There are no randomized controlled trials to help guide therapeutic decision making, but there is data to suggest that treatment of severe NPSLE with IV cyclophosphamide may be of benefit. Additionally, there may be a role for IVGG or synchronized plasmapheresis in cases that fail to respond to IV-CYC. An important role for sex steroids in the etiology of NPSLE is suggested by various observations. Investigational therapy with dehydroepiandrosterone (DHEA) appeared to have benefits with respect to milder symptoms of NPSLE.

Central Nervous System Diseases↗
PubMed1995

Changes in the sweatspot test with ageing and relation to cardiovascular autonomic function.

The sweatspot test assesses the local sweat response to an intradermal injection of acetylcholine. It has been reported as a more sensitive indicator of autonomic dysfunction in important diabetic men than either pupillary or cardiovascular tests, and has been used to establish the presence of autonomic dysfunction in patients with idiopathic chronic constipation. However, the usefulness of this test as a simple and quick method of diagnosing autonomic dysfunction in an elderly population has not been established. This is important given the high prevalence of reduced autonomic function with ageing and hypertension. We compared the age-associated responses in the sweatspot test and its relation to cardiovascular autonomic function in elderly normotensive and hypertensive subjects. We studied eleven normotensive and 24 untreated hypertensive elderly subjects (mean age 75.7 years, range 63-85) and compared the results of the sweatspot test to a young control group (n = 11, mean age 32.0 years, range 25-41), and to a standard battery of cardiovascular autonomic function tests. The median sweatspot score was significantly lower in the elderly compared with young subjects (1.9 vs. 12.0, p < 0.0001) although there was no difference between elderly normotensive and hypertensive subjects (1.6 vs. 2.4, p = 0.8). No correlation was demonstrated between the median sweatspot score and the number of abnormal cardiovascular tests. The sweatspot test was grossly abnormal in all elderly subjects and was not correlated to changes in cardiovascular autonomic function. Its diagnostic use in the elderly is therefore of very limited value.

Acetylcholine↗
PubMed1995

Structure and specificity of T cell receptors expressed by potentially pathogenic anti-DNA autoantibody-inducing T cells in human lupus.

The production of potentially pathogenic anti-DNA autoantibodies in SLE is driven by special, autoimmune T helper (Th) cells. Herein, we sequenced the T cell receptor (TCR) alpha and beta chain genes expressed by 42 autoimmune Th lines from lupus patients that were mostly CD4+ and represented the strongest inducers of such autoantibodies. These autoimmune TCRs displayed a recurrent motif of highly charged residues in their CDR3 loops that were contributed by N-nucleotide additions and also positioned there by the recombination process. Furthermore, Th lines from four of the five patients showed a marked increase in the usage of the V alpha 8 gene family. Several independent Th lines expressed identical TCR alpha and/or beta chain sequences indicating again antigenic selection. 10 of these Th lines could be tested further for antigenic specificity. 4 of the 10 pathogenic anti-DNA autoantibody-inducing Th lines responded to the non-histone chromosomal protein HMG and two responded to nucleosomal histone proteins; all presented by HLA-DR molecules. Another Th line responded to purified DNA more than nucleosomes. Thus, these autoimmune Th cells of lupus patients respond to charged epitopes in various DNA-binding nucleoproteins that are probably processed and presented by the anti-DNA B cells they selectively help.

Amino Acid Sequence↗
PubMed1995

What method should be used to define 'night' when assessing diurnal systolic blood pressure variation in the elderly?

Diurnal blood pressure (BP) variation can be assessed by cusums-derived measures and by the day-night BP difference from time-, activity- and diary-defined 'night' periods. Reproducibility of diurnal systolic BP (SBP) variation by these different methods was studied in 19 active elderly normotensives, mean age 68.5 years. Subjects underwent simultaneous 24 h BP (Spacelabs 90207) and activity (Gaehwiler wrist actigraph) monitoring on two occasions (median interval 70 days). On the first occasion, mean diurnal SBP variation was 15.1 +/- 8.1 mm Hg by fixed-time definition of 'night' (22.07). When compared with 22-07 defined 'night' period, actigraph- and diary-defined 'night-time' was significantly reduced (-60 +/- 49, and -48 +/- 51 min, respectively) and consequently diurnal SBP variation was significantly greater at 18.2 +/- 8.1 mm Hg and 17.6 +/- 8.4 mm Hg, respectively. Actigraph recordings were also used to exclude 'night' BP readings associated with activity, but this did not significantly alter the diurnal SBP variation. Cusums-derived circadian alteration magnitude resulted in the greatest value for SBP variation (23.4 +/- 6.7 mm Hg). However, reproducibility of diurnal SBP variation was poor by fixed-time method with a coefficient of variation (CV) of > 50%, and only improved to 40% with diary use. Actigraph measurements, even if used to exclude BP values associated with disturbed sleep, did not improve this further. Cusums-derived measures of diurnal variation slightly improved reproducibility with a CV of 34.6% and may be a better method in the assessment of diurnal BP variation in the elderly.

Aged↗
PubMed1994

Orbital emphysema: how common, how significant?

STUDY OBJECTIVE: To describe the natural history of orbital emphysema and its management in the emergency setting. DESIGN: Retrospective medical record review. SETTING: Inner-city integrated hospital system (four divisions) including one Level I trauma center. PARTICIPANTS: All cases of orbital floor fracture and orbital emphysema from January 1, 1988, to December 31, 1993. RESULTS: The average patient was aged 33 years, and the male-to-female ratio was 7 to 1. Trauma was the underlying etiology in all patients. Seventy-four percent of patients required hospitalization, and 43% developed significant complications. Eighty-three percent were managed with antibiotics. Orbital emphysema was identified on conventional radiographs in 65% of cases. CONCLUSION: Identification of orbital emphysema in the ED should prompt a careful search for associated injury. Consultation should be sought in the presence of orbital or ocular injury. Antibiotic prophylaxis is not necessary for clean wounds.

Adolescent↗
PubMed1994

Postcopulatory, prezygotic isolation: intraspecific and interspecific sperm precedence in Tribolium spp., flour beetles.

We investigated intraspecific and interspecific patterns of paternity in Tribolium castaneum, the flour beetle, by mating females either to pairs of conspecific males or to one conspecific and one heterospecific male of the closely related species, T. freemani. Females of both species store sperm in the spermatheca after copulation and postcopulatory, prezygotic reproductive isolation has been reported between this pair of species. When conspecific males of contrasting genotype are mated simultaneously to T. castaneum females, we observed extremely high levels of variation among females in the pattern of sperm precedence as shown by the offspring genotypes. In contrast, T. castaneum females mated simultaneously to a conspecific and a heterospecific male produced over 99 per cent conspecific progeny. When conspecific males were mated sequentially to T. castaneum females, within 3-7 days, all offspring were sired by the second male. In contrast, when a conspecific male was replaced with a T. freemani male, most females continued to produce only first-male, conspecific offspring for the next 10 days. When a heterospecific male was replaced with a conspecific male, T. castaneum females changed from producing hybrid to conspecific offspring within 3 days. We discuss the evolutionary implications of these findings.

Animals↗
PubMed1994

The acute effects of a single dopamine infusion in elderly patients with congestive cardiac failure.

1. Dopamine (DA) at low doses (2.5 micrograms kg-1 min-1) produces a measurable increase in glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) in young healthy subjects and has a therapeutic effect in younger patients with congestive cardiac failure (CCF). In elderly healthy subjects, DA increases ERPF but does not increase GFR in all subjects. 2. To determine the potential therapeutic use of DA in elderly subjects with CCF, we studied 17 patients (5 male) aged 79.9 years (range 68 to 93 years) admitted to hospital for inpatient treatment of CCF resistant to diuretic and angiotensin converting enzyme inhibitor therapy. The effects of a single infusion DA at 2.5 micrograms kg-1 min-1 on GFR and ERPF were assessed in a double-blind, placebo controlled prospective study. 3. There were no significant differences in GFR or ERPF between control and DA. A reduction in GFR was seen in some patients. 4. DA at low dosage was not shown to benefit elderly patients with resistant CCF, and in some patients was detrimental. Higher doses or a combination with other inotropes may be necessary for a renal effect in elderly patients.

Aged↗
PubMed1994

In vitro and ex vivo effects of cyclosporin A on phagocytic host defenses against Aspergillus fumigatus.

Because cyclosporin A (CsA) is extensively used as an immunosuppressive agent, its effects on phagocytic defenses against Aspergillus fumigatus were studied in vitro and ex vivo. After incubation with 10 to 250 ng of CsA per ml at 37 degrees C for 60 min, polymorphonuclear leukocytes (PMNs) exhibited unaltered superoxide anion (O2-) production in response to phorbol myristate acetate and N-formylmethionyl leucyl phenylalanine, whereas > or = 500 ng/ml significantly suppressed it (P < 0.01). Moreover, at < 250 ng of CsA per ml, PMNs exhibited no change in their capacity to damage unopsonized hyphae of A. fumigatus compared with controls, whereas at > or = 250 ng/ml, CsA suppressed the function (P < 0.01). Although neither CsA (250 ng/ml) nor hydrocortisone (10 micrograms/ml) suppressed PMN O2- production in response to phorbol myristate acetate and N-formylmethionyl leucyl phenylalanine, combination of the two agents reduced the function compared with that at the baseline (P < 0.05). Incubation of monocytes with 100 ng of CsA per ml for 1 or 2 days suppressed their antihyphal activity. No essential change in phagocytic activity of monocyte-derived macrophages (MDMs) against A. fumigatus conidia, tested as the percentage of phagocytosing MDMs and average number of MDM-associated conidia, was detected after 2 or 4 days of incubation with 10 to 1,000 ng of CsA per ml. Furthermore, in rabbits treated with CsA (up to 20 mg/kg of body weight per day intravenously for 7 days), neither O2- production and hyphal damage caused by PMNs or monocytes against hyphae nor phagocytosis of conidia by pulmonary alveolar macrophages was significantly suppressed. Thus, these results demonstrated that CsA within therapeutically relevant concentrations does not suppress antifungal activity of phagocytes except that of circulating monocytes. However, it may induce significant immunosuppression of phagocytes' antifungal function at relatively high concentrations in vitro, especially when combined with corticosteroids.

Adult↗