Biomedical subjects

C M Braun

Publications and source records attributed to C M Braun.

At least 19 recordsLinked to original sources

PubMed2001

Cancer care in Nepal: variables that affect diagnosis, treatment, and prognosis: a case study.

This manuscript presents a case study of a Nepalese woman experiencing breast cancer. Six themes were identified to have an impact on the diagnosis, treatment, and prognosis. They include: cultural impact on women's roles, socioeconomic status and education, surgical oncologist-patient relationship, surgical oncologist-nurse relationship, nurses' lack of oncology knowledge, and lack of a cancer screening and prevention program in Nepal. Cancer care is on the rise in Nepal. However, many of the variables identified above are not considered in the cancer care provided. Nepal has just opened its first national cancer center with the intent to improve cancer care throughout the country.

Adult↗

PubMed2001

Liver lipid accumulation in duck embryos and hatchlings change with parental age.

The purpose of this study was to investigate the effects of duck breeder age on liver lipid accumulation and yolk absorption and utilization in duck embryos (day 25 of incubation) and newly hatched ducklings. One breeder flock was monitored at 24 (young breeders), 31 (mature breeders and near peak egg production) and 47 (post peak egg production) weeks of age. Electron microscopy images of duck embryo liver slices revealed a significant change in hepatic lipid accumulation as a function of breeder age. More specifically, as breeder age increased both the relative number of liver lipid droplets as well as the size of the lipid droplets increased in duck embryos (day 25 of incubation). At hatch, however, newly hatched ducklings from 31-week-old breeders exhibited the lowest number as well as the smallest sized lipid droplets when compared to ducklings from 24 or 47-week-old breeders. The trend in yolk absorption at day 25 as a function of breeder age paralleled that in liver lipid accumulation. That is, day 25 maintained a higher percentage of unabsorbed yolk when compared to embryos from 31- or 47-week-old breeders. In contrast to breeder age, time of incubation (day 25 vs. day 28 or hatch) had little effect on yolk fatty acid profiles when compared to breeder age. Although there were no clear trends in yolk fatty acid usage among the various ages of breeders, newly hatched ducklings from 31-week-old breeders did have a significantly higher proportion of 18:2 n6 compared to those from breeders at 24 or 47 weeks of age. These data would suggest that breeder age subsequently affects the relative number and size of liver lipid droplets in embryos and newly hatched ducklings.

Aging↗

PubMed2000

Right body side performance decrement in congenitally dyslexic children and left body side performance decrement in congenitally hyperactive children.

OBJECTIVE: Simple and complex visuomotor performance of the right and left sides of the body was investigated in 37 children with left hemisphere lesions, 35 children with right hemisphere lesions, 53 developmentally dyslexic children, 29 developmentally hyperactive children, and 35 "normal" children who had endured a very mild head injury with no sequelae. BACKGROUND: Lateralized soft signs, EEG topography, metabolic brain imaging, and neuropsychological test profiles suggest a predominance of left hemisphere dysfunction in dyslexia and right hemisphere dysfunction in hyperactivity. METHOD: Nine measures of lateralized performance were drawn from the Purdue pegboard, Letter cancellation, Rey complex figure, Wechsler Intelligence Scale for Children (WISC) Mazes, and WISC Picture completion tests. RESULTS: The children with left hemisphere lesions manifested significantly weaker performance on test components involving the right body side, relative to the normal controls, on the Purdue pegboard, Rey complex figure (delayed recall condition), and WISC Picture completion tests, and the dyslexic children on the former two. The children with right hemisphere lesions manifested significantly weaker performance on test components involving the left body side, relative to the normal controls, on the WISC Mazes test, as did the hyperactive children. CONCLUSIONS: We propose that (1) contralateral performance decrement results from a unilateral cortical lesion in children, and (2) developmental dyslexia may comprise a slight predominance of left hemisphere dysfunction and developmental hyperactivity of right hemisphere dysfunction.

Attention↗

PubMed1999

Topography of averaged electrical brain activity relating to interhemispheric dynamics in normal humans: where does the critical relay take place?

Interhemispheric relay time (IHRT) was investigated using a 16-electrode montage in 10 normal subjects during a simple visual reaction time task (Poffenberger paradigm). The P1 latency was the dependent measure. Response-locked components were separated from the stimulus-locked components based on the reaction times using a Woldorff-like filter. The issues of theoretical interest were the following: (1) does the responding hand modulate IHRT estimates as a function of electrode site, or stimulated field?; (2) what are the respective advantages of various pairs of symmetrical across-midline electrode sites for tracking IHRT?; and (3) what are the respective advantages of symmetrical vs. asymmetrical across-midline electrode site-pair configurations for tracking IHRT? There were significant lags attributable to IHRT in both evoked potential P1 latencies and in reaction times--but these were uncorrelated. The responding hand was not found to significantly modulate IHRT estimates derived from the P1 peak latency of response-corrected ERPs. Anterior sites yielded more precocious components and briefer estimates of IHRT which were closer to those observed in reaction time estimates. However, posterior leads yielded more reliable estimates. Various analyses suggested that IHRT can be tracked, very vaguely, with asymmetric configurations as well as symmetric ones, each for different reasons.

Adult↗

PubMed1999

Components of an optimal exercise program for the treatment of patients with claudication.

Research in vascular exercise has demonstrated remarkable improvement in symptoms of claudication without more expensive and invasive interventions. During the past 5 years, 86 patients have graduated from The Brown University Supervised Vascular Exercise Program. Patients demonstrate a threefold improvement in maximum walking distance after 12 weeks of training. Information available on 22 patients at 1-year and 2-year follow-ups show walking distance is improved or maintained with continued training. Components of the program are presented in 3 phases. Phase 1 addresses the comprehensive nursing assessment, cardiac screening, and progressive treadmill testing. Phase II includes specific method of exercise prescription and educational needs of peripheral vascular disease patients. Phase III discusses the importance of maintenance and motivating patients to continue.

Aged↗

PubMed1999

Topographical analysis of homotopic interhemispheric "relay" asymmetries in visual evoked potentials.

Brown and colleagues (1994) found that most evoked potential studies provide evidence of faster interhemispheric relay from the right to the left hemisphere, as determined from N160 latencies derived from parietal and occipital electrode sites. The experiment reported here was designed to complement those findings by 1) analyzing more electrode sites (several frontal, temporal, and central sites in addition to the previously investigated sites) and more waveforms (P1 and P2 waves); 3) introducing analysis of amplitude data; 4) carrying out site-specific and experiment-wise inference tests of putative interhemispheric relay asymmetry. We found that all of the conclusions of Brown and colleagues, regarding latency effects, could be extended to the ensemble of electrode sites and waveforms. However, amplitude effects were significantly compatible with stronger (though slower) relay from the left to the right hemisphere.

Adult↗

PubMed1999

Mania, pseudomania, depression, and pseudodepression resulting from focal unilateral cortical lesions.

OBJECTIVE: This consecutive multiple case study was designed to determine whether cortical lesion sites can predict occurrence of mood or psychomotor disorders in adults and children. BACKGROUND: Most of a large body of research supports the contention that left hemisphere lesions result more often than right ones in depression, and that the inverse occurs in mania. However, it is not clear how psychomotor status fits into this picture, nor whether children respond to the same lesions in a similar manner. METHOD: Published (n = 88) and unpublished (n = 31) cases of school-aged child and adult patients with focal unilateral cortical lesions and psychomotor agitation or lethargy with or without corresponding mania or depression were reviewed systematically to determine whether lesion location relates systematically to any of those psychiatric conditions. No patients had symptoms prior to detection of their lesion. Manic-depressives and agitated depressives were also excluded. RESULTS: Patients with mania and/or psychomotor agitation had predominantly right hemisphere lesions. Postlesion hyperactivity (without mania) in children was common but was not more related to lesions in one or the other hemisphere. Adult and child patients with depression and/or psychomotor lethargy had predominantly left hemisphere lesions. The intrahemispherical site of the lesion did not significantly predict the type of mood or psychomotor disorder. Nevertheless, the nonsignificant trend was for right posterorolandic lesions to predict mania or agitation and for left frontal lesions to predict depression or psychomotor lethargy. CONCLUSIONS: These findings support the neuropsychiatric approach to mood and psychomotor disorder in children and adults.

Adult↗

PubMed1998

Co-regulation of antigen-specific T lymphocyte responses by type I and type II cyclic AMP-dependent protein kinases (cAK).

While a differential sensitivity to cyclic AMP (cAMP)-mediated signaling between Th1 and Th2 cells has been hypothesized, differential activity of downstream signaling through cAMP-dependent protein kinase (cAK) isoforms remains unexplored. We herein report the effects of type 1- and type 2-specific cAK agonists and antagonists on proliferative responses and cytokine generation from ragweed-driven peripheral blood mononuclear cells (PBMCs) and Amb a 1-specific Th1 and Th2 clones. Rp-8-Cl- and Rp-8-CPT-cAMP were utilized as single agent antagonists of cAKI and cAKII, respectively; 8-AHA-cAMP, with and without 8-PIP-cAMP, and 8-CPT-cAMP, with and without 6-Bnz-cAMP, were used as synergistic agonist pairs specific for the cAKI and cAKII, respectively. Activation of either cAKI or cAKII individually was ineffective in down-regulating proliferative responses of PBMCs or T cell clones; concentration-response curves for the Th1 and Th2 clones were identical. Moreover, inhibition of either cAKI or cAKII individually was ineffective in overcoming the down-regulatory effects of phosphodiesterase inhibition. Activation of either cAKI or cAKII individually was ineffective in down-regulating proinflammatory cytokine generation from T cell clones (interleukin-4 from Th2; interferon-gamma from Th1). However, concurrent activation of both cAKI and cAKII produced down-regulatory effects equivalent to those of the phosphodiesterase inhibitor on both proliferation and cytokine generation. These data suggest a critical role for concurrent activation of cAKI and cAKII in the functional efficacy of antigen-driven downstream signaling due to elevations of intracellular cAMP and argue against differential regulation of Th1 and Th2 responses by cAK subtypes.

Allergens↗

PubMed1998

Effects of peptide therapy on ex vivo T-cell responses.

BACKGROUND: Peptide therapy targets T cells directly with short peptides containing multiple T-cell receptor epitopes. Murine studies suggest T-cell anergy as the mechanism of action; however, changes in T-cell cytokine profiles may be more relevant in human beings. OBJECTIVE: We sought to study the effects of peptide therapy on ex vivo antigen-specific T-cell responses. METHODS: Antigen-specific T-cell lines were generated from subjects enrolled in a double-blind, placebo controlled, two-dose study of the ALLERVAX CAT therapeutic, containing Fel d 1 peptides (ImmuLogic Pharmaceutical Corp., Waltham, Mass.) (n = 7, 8, and 7, respectively, for groups receiving placebo, 75 microg, or 750 microg). Each subject had three lines propagated before and after receiving peptide therapy; antigens used were cat hair extract, Fel d 1 peptides, and tetanus toxoid (negative control). Proliferative responses and cytokine generation from each line were assessed after two restimulations with antigen and autologous antigen-presenting cells. RESULTS: The Fel d 1 peptide lines showed a dose-dependent decrease of IL-4 production (p = 0.02 and 0.025, respectively, for the 750 microg group vs both the 75 microg and placebo groups). IL-4 production from the cat hair allergen extract lines and interferon-gamma production from both the Fel d 1 peptide lines and cat hair allergen extract lines showed no statistically significant changes. The control tetanus toxoid lines showed no changes in cytokine production; there were no significant changes in proliferation with any of the antigens in any of the treatment groups. In the clinical arm of the trial, only the 750 microg dose of peptides produced a significant response. CONCLUSIONS: Peptide therapy induces a significant, dose-dependent decrease in peptide-stimulated IL-4 production, consistent with either a shift in T-cell phenotype or peptide-specific T-cell tolerance.

Allergens↗

PubMed1998

Dissociation of hemispheric exploitation of rods and cones for simple detection.

Sergent (1982a, 1982b, 1982c) proposed that stimuli carrying high luminous energy will be better detected in the right field (left hemisphere) and stimuli carrying low energy in the left visual field (right hemisphere). A photoreceptor-based model could explain the same effects as well as several others (eccentricity effects, retinal adaptation effects). Braun, Mailloux, and Dufresne (1995) suggested that cones might favor right field stimuli and rods might favor left field stimuli. We implemented a series of near-threshold simple detection experiments comprising stimuli varying along four dimensions (color, eccentricity, duration, and size) in dark-adapted subjects. Consistent and significant right field advantages accrued for near-meridianal foveal red stimuli, but there were no field effects for eccentric blue stimuli. An alternative to Sergent's stimulus energy model and the photoreceptor-based model, namely a parvocellular-magnocellular model, is proposed.

Adult↗

PubMed1998

Pseudoakathisia from a acquired lesion.

Akathisia, "inability to remain seated", is a common condition in patients medicated with neuroleptics, and also occurs in other medication regimens. Only a few cases of akathisia resulting from focal lesions have been published. These cases suggest that differing lesion sites are sufficient for producing objective or subjective akathisia. The authors present a patient with akathisia who had no subjective complaints, suggesting that a combined basal ganglia and frontal lobe lesion may lead to objective akathisia (pseudoakathisia).

Adolescent↗

PubMed1997

The "Poffenberger" and "Dimond" paradigms: interrelated approaches to the study of interhemispheric dynamics?

Brown and Jeeves (1993) found that an evoked potential estimate of interhemispheric transfer time, from the left to the right hemisphere, correlated negatively with a bilateral field advantage (BFA) in a response-choice letter matching task. We implemented a go no-go dot size matching task to determine whether the crossed-uncrossed difference (CUD) in reaction time, commission errors and omission errors (estimates of the "cost" of interhemispheric transfer) would correlate with BFAs in data from the same experiment and whether the type of decision ("same" versus "different") would modulate the CUDs and/or BFAs. Sixteen normal right-handed subjects were tested. The CUDs were negatively correlated with the BFAs. Canonical correlation analysis of this set of relations was highly significant (r = .95). Estimates of left-to-right relay were far more strongly related to BFA (p = .0001) than were estimates of right-to-left relay (p = .03). "Same" decisions yielded a unilateral field advantage and "different" decisions a bilateral field advantage in omission error data, this crossed interaction reaching significance. More efficient interhemispheric relay favored BFAs, i.e., strongly suggesting in such cases an advantage of interhemispheric over intrahemispheric integration. This effect appeared to be markedly asymmetric. Furthermore, resource sharing within and between the hemispheres was a function of the "same" versus "different" dimensions of the decision to be made, especially in omission errors. The opposite dissociation occurred less markedly in the reaction times, this double dissociation reaching significance, revealing presence of a subtle speed-accuracy trade-off in interhemispheric dynamics.

Adult↗

PubMed1997

Corticosteroid modulation of human, antigen-specific Th1 and Th2 responses.

Corticosteroids are potent antiinflammatory agents that modulate human T-lymphocyte responses. Controversy remains as to their possible differential effects on Th1 and Th2 subsets. This study explores the kinetics and efficacy of these agents in human, antigen-driven peripheral blood mononuclear cells (PBMCs) and in nontransformed, antigen-specific Th1 and Th2 clones. Ragweed- and tetanus toxoid-driven proliferative responses of PBMCs from dually sensitized individuals were downregulated equally by dexamethasone (inhibitory concentration of 50% [IC(50)] = 3 x 10(-9) and 2 x 10(-9) mol/L, respectively). The addition of dexamethasone as late as 36 hours after ragweed stimulation still resulted in more than 75% inhibition of the proliferative response, whereas the efficacy of dexamethasone was less than 50% when added 24 hours after tetanus toxoid stimulation. Antigen-induced gene expression for proinflammatory cytokines (IL-4, IL-5, IL-13, and interferon-gamma) from PBMCs was also downregulated by dexamethasone. Proliferation of antigen-specific Th1 and Th2 clones was inhibited by several corticosteroids (hydrocortisone < budesonide < dexamethasone; IC(50) = 10(-6) to 10(-8) mol/L), but no significant differences between Th1 and Th2 clones were evident. IC(50) values in the clones were 10-fold greater than in PBMCs. Gene expression and protein secretion for IL-4, IL-13, and interferon-gamma were downregulated in a concentration-dependent manner by each of the corticosteroids in Th1 and Th2 clones. These data suggest that Th1 and Th2 responses are equally affected by corticosteroids.

Adrenal Cortex Hormones↗

PubMed1997

Differential regulation of human, antigen-specific Th1 and Th2 responses by the B-7 homologues, CD80 and CD86.

A selectivity of B7.1 (CD80) for promoting Th1 responses and B7.2 (CD86) for promoting Th2 responses in the murine system has recently been suggested. The present study explores this hypothesis, using human PBMCs and antigen-specific Th1 and Th2 clones. Proliferative responses of peripheral blood mononuclear cells (PBMCs) from ragweed-allergic, tetanus toxoid-immunized individuals were downregulated by treatment with anti-CD86 in ragweed- and tetanus toxoid-driven cultures (% Inhibition = 55 +/- 4 and 61 +/- 12, respectively; P < 0.03 relative to untreated cultures). Gene expression in PBMCs for interleukin (IL)-4, IL-5, and interferon gamma (IFNgamma), assessed by reverse-transcriptase polymerase chain reaction, was also downregulated by treatment with anti-CD86 in both the ragweed- and tetanus toxoid-driven systems. Neither independent efficacy nor synergy with anti-CD86 was apparent with anti-CD80 treatment; two different anti-CD80 blocking antibodies yielded identical results. Conversely, antigen-specific Th1 and Th2 clones were insensitive to treatment with either anti-CD80, anti-CD86, or a combination of the two. Unaffected parameters included proliferative response (P < 0.14 and 0.33, respectively, for Th1 and Th2), proinflammatory cytokine gene expression, and cytokine protein secretion into culture supernatants (P < 0.44 and 0.16, respectively, for IL-4 and IFNgamma). We conclude that CD86 is the primary B7 signaling homologue in human PBMC responses, and that second signal pathways through the B7 homologues have no effect on phenotypically differentiated T helper cells in humans.

Antigens, CD↗

PubMed1996

Intermanual transfer of somaesthetic information: a two-point discrimination experiment.

Twenty-four men and 24 women, all university students, judged whether two-point aesthesiometric applications, either both to the same palm (intramanual condition) or one to each palm (intermanual condition) were of the "same" or "different" spans. The main question was to determine the extent to which there is a loss of accuracy during intermanual comparisons, and by inference, interhemispheric relay. A second question, the extent to which this loss is a function of the difficulty of the task, was to be answered by the inclusion of span-differences above, at, and below threshold. Difficult trials were associated with a highly significant intramanual advantage of 4.74%, and easy trials with a non-significant intramanual advantage of 1.16%. For both intra- and intermanual conditions, subjects made more errors as a function of decreasing "span-difference". The two hands performed equally well, and the order of stimulation between the two hands made no difference in the results. The intramanual advantage could not be construed as an effect of response set (i.e., an artefact of subject's inherent bias for "same" or "different" judgements), nor as a scaling effect (e.g., of span scales relating to receptive field properties, relating in turn to interhemispheric relay). There was no evidence of a sex difference in basic ability, nor in the cost of hemispheric relay. It was concluded that there is a loss of precision in interhemispheric relay of somaesthetic discrimination, but this can only be detected close to threshold.

Adult↗

PubMed1995

Ventral frontal deficits in psychopathy: neuropsychological test findings.

The hypothesis of prefrontal dysfunction in psychopathy has been pursued for many years, without convincing results. It is proposed here that this approach in previous studies was far too global. The present investigation was carried out in order to test a more specific hypothesis of orbitofrontal and/or frontal ventromedial deficits in psychopathy. Psychopathic criminals were compared to non-psychopathic criminals with measures related to orbitofrontal or frontal ventromedial functioning, as well as with control measures more associated with frontodorsolateral and posterorolandic functions. All subjects provided urine samples for drug assay. It was found that, while the two groups performed similarly on all the control measures, including the drug tests, the psychopaths were significantly impaired on all the orbitofrontal-ventromedial tasks. The psychopaths were significantly impulsive on several tests as well as significantly dysosmic [corrected]. The latter finding is particularly important in the sense that it cannot readily be explained socioculturally, thus presenting a new and convincing argument for brain-based etiology of this disorder. The results are discussed in relation to other psychiatric disorders characterized by impulse dyscontrol as well as in relation to other putative neurobiological etiological factors in psychopathy.

Adult↗

PubMed1995

Neuropsychological correlates of violence in schizophrenia.

Thirty-one outpatient men with schizophrenia were assessed with various measures of lifelong history of physical violence as well as psychopathology, neuropsychological performance, and neurological intactness. Most of the results consisted of nonsignificant positive relationships between physical aggression and neuropsychological performance in these schizophrenia subjects. Some neuropsychological test performances did show significant positive correlations with levels of aggressivity. In contrast with previous studies that have established a relation between neuropsychological impairment (as opposed to performance) and violence in schizophrenia, subjects of the present study were high-functioning outpatients who may not have attained a level of neurological impairment inducing constant uncontrollable outbursts of irritative aggression in their daily living. The importance of defining in detail the clinical characteristics of the subjects studied and the type of violence assessed is discussed, and an ecological interpretation of these counterintuitive results is provided.

Activities of Daily Living↗

PubMed1995

[Vocal and respiratory diadochokinesia in Friedreich's ataxia. Neuropathological correlations].

Acoustic analysis of unvoiced diadochokinetic respiratory cycles helped identify two kinds of impairments in ten Friedreich's ataxia patients. Four patients manifested moderate problems maintaining regularity in the repetition of unvoiced respiratory cycles, and also showed moderate articulatory dysarthric problems in a syllabic repetition task. Six patients had severe respiratory insufficiency in the inspiration/expiration repetition task, and exhibited very important amplitude and fundamental frequency disturbances and a much slower rate of syllabic utterances. This respiratory insufficiency and aggravated speech disorders were linked to presence of pontine and medullary atrophy, sites comprising the respiratory centers of the brain stem.

Adult↗