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Biomedical subjects

M Grossman

Publications and source records attributed to M Grossman.

At least 55 records · Page 3Linked to original sources
PubMed2000

Response of males and females to high-force eccentric exercise.

It has previously been shown that females incur less muscle damage than males after strenuous exercise, but limited data are available for humans. To determine possible differences between the sexes in humans, the response to high-force eccentric exercise was examined in a large sample of women (n = 83) and men (n = 82). The participants performed a bout of eccentric exercise of the elbow flexors consisting of 70 maximal repetitions. Isometric strength, resting elbow angle and muscle soreness were measured before, immediately after (except soreness) and then daily for 7 days after exercise. There was a significant loss in strength among both groups (69% for women and 63% for men) (P < 0.01) immediately after exercise; at 168 h post-exercise, women still had a 27% strength loss and men had a 24% strength loss. No significant difference in strength loss or recovery rate was found between men and women. Soreness reached peak values 32-48 h post-exercise (P < 0.01), with no significant difference between men and women. Range of motion decreased significantly until 3 days after exercise (14.6 degrees or 0.255 rad loss for women; 12.2 degrees or 0.213 rad loss for men) (P < 0.01); at 168 h post-exercise, the women and men still showed a loss of 4.8 degrees (0.084 rad) and 4.0 degrees (0.07 rad), respectively. There was a significant interaction of sex x time (P < 0.01); a post-hoc test indicated that the women experienced a greater loss in range of motion at 72 h than men and this difference was maintained to 168 h post-exercise (P < 0.01). Thus, our results do not support the contention that women have a lower response to eccentric exercise than men.

Adult↗
PubMed2000

Immunohistochemical and biochemical studies demonstrate a distinct profile of alpha-synuclein permutations in multiple system atrophy.

Although alpha-synuclein (alpha-syn) has been implicated as a major component of the abnormal filaments that form glial cytoplasmic inclusions (GCIs) in multiple system atrophy (MSA), it is uncertain if GCIs are homogenous and contain full-length alpha-syn. Since this has implications for hypotheses about the pathogenesis of GCIs, we used a novel panel of antibodies to defined regions throughout alpha-syn in immunohistochemical epitope mapping studies of GCIs in MSA brains. Although the immunostaining profile of GCIs with these antibodies was similar for all MSA brains, there were significant differences in the immunoreactivity of the alpha-syn epitopes detected in GCIs. Notably, carboxy-terminal alpha-syn epitopes were immunodominant in GCIs, but the entire panel of antibodies immunostained cortical Lewy bodies (LBs) in dementia with LBs brain with similar intensity. While the distribution of alpha-syn labeled GCIs paralleled that previously reported using silver stains, antibodies to carboxy-terminal alpha-syn epitopes revealed a previously undescribed burden of GCIs in the MSA hippocampal formation. Finally, Western blots demonstrated detergent insoluble monomeric and high-molecular weight alpha-syn species in GCI rich MSA cerebellar white matter. Collectively, these data indicate that alpha-syn is a prominent component of GCIs in MSA, and that GCIs and LBs may result from cell type specific conformational or post-translational permutations in alpha-syn.

Aged↗
PubMed2000

A model for persistency of egg production.

The objectives of our study were to propose a new definition for persistency of egg production and to develop a mathematical model to describe the egg production curve, one that includes a new measure for persistency, based on the proposed definition, for use as a selection criterion to improve total egg production. Persistency of egg production is an important determining factor for total egg production. Hens with the same total production, however, can exhibit different egg production curves because of differences in persistency. We propose a new definition for persistency of egg production: the number of weeks during which a level of constant production is maintained. No egg production model exists that includes a measure of persistency in terms of duration of time or that allows this measure of persistency to be derived from model parameters. It was necessary, therefore, to develop a new model to describe an egg production curve for a flock: equation [see text] and for an individual: equation [see text] where y(t) = egg production at time t, t1 and t2 = times at transition, r = duration of transition, y(p) = level of constant production, b4 = rate of decline in production, and P = persistency of constant production. These parameters measure directly the important biological characteristics of an egg production curve. To illustrate the model, six data sets were used: two from flocks (one pullet flock and one hen flock) and four from two pairs of individuals. The proposed definition of persistency should be important for genetic selection because it might be desirable to select for increased persistency. The novel approach to the definition and measure of persistency presented here should provide a better understanding of the relationship between the new measure of persistency and other characteristics of egg production.

Animals↗
PubMed2000

Nutrient flows for poultry production in The Netherlands.

Government targets for ammonia emission and for N and P loss per hectare (ha) of agricultural land were used to assess carrying capacity for poultry production in The Netherlands with data from 1990. In addition, the effect of alternative management strategies on carrying capacity was determined. Ammonia emission from poultry production in 1990 [20.5 gigagrams (Gg) N] exceeded the target for 2000 (i.e., 6.9 Gg N). Targets defined for 2000 and 2010 (i.e., 4.6 Gg N) can be achieved, however, without reducing poultry numbers, assuming national introduction of measurements studied. Measures that reduced ammonia emission directly, i.e., introduction of low-emission housing or manure application techniques, were most effective. In 1990, N and P losses equalled 215 kg/ha for N and 31 kg/ha for P. The N loss was slightly lower than the target for 2000 (219 kg N/ha) but exceeded the target for 2010 (144 kg N/ha). Reduction of application of artificial N fertilizer, however, reduced N loss effectively from 215 to 22 kg/ha. National P loss in 1990 exceeded the target for 2000 (15.3 kg P/ha). Reduction of application of artificial P fertilizer reduced P loss most effectively from 31 to 14 kg/ha. To achieve the target for 2010 (8.7 kg P/ha), additional reduction in P excretion by poultry is required. This reduction can be achieved by use of phytase in layer and broiler feed and by use of a coarse Ca source in layer feed. Unlike pig production, carrying capacity for poultry production in The Netherlands is not limited by governmental targets for acidification, eutrophication, or drinking water contamination.

Ammonia↗
PubMed2000

Regional cerebral distribution of [Tc-99m] hexylmethylpropylene amineoxine in patients with progressive aphasia.

Progressive aphasia is a prominent clinical feature of several neurodegenerative disorders. This study used hexylmethylpropylene amineoxine (HMPAO) single photon emission computed tomography (SPECT) to estimate blood flow in areas of the brain that mediate language in patients with progressive aphasia and matched control subjects. The patient population consisted of four men and 12 women with a mean +/- SD age of 69.1 +/- 7.6. Of these, eight were classified as having a nonfluent form of aphasia, whereas the other eight had a fluent form. The patients were compared to 16 healthy volunteers who were studied with an identical protocol. The SPECT images of the brain were acquired with 740 MBq (20 mCi) of Tc-99m-labeled HMPAO on a triple-headed gamma camera equipped with fan beam collimators. The images were analyzed with a set of standardized templates. Mean counts per pixel in 33 regions of interest were compared to the mean counts in the whole supratentorial brain. A laterality index was determined for homotopic regions using the equation 100 x (R - L)/(1/2 x (R - L)). Patients with progressive aphasia had several regions of significantly decreased HMPAO uptake in the left cortex when compared to the homotopic regions on the right. The most prominent deficit in the nonfluent group, as determined by the laterality index, were found in the left dorsolateral prefrontal region (p < 0.05), whereas the most prominent deficits in the group with fluent aphasia were found in the left temporal and parietal language centers (p < 0.05). The left subcortical nuclei were differentially affected, particularly in patients with nonfluent aphasia. The HMPAO SPECT indicates that multiple regions of the left hemisphere are dysfunctional in patients with progressive aphasia. The pattern of perfusion deficits in patients with fluent aphasia appears to be distinct from the pattern in patients with nonfluent aphasia.

Aged↗
PubMed2000

Assessment of cerebral blood flow in Alzheimer's disease by spin-labeled magnetic resonance imaging.

To evaluate the utility of arterial spin-labeled blood flow magnetic resonance imaging for the detection of cerebral blood flow abnormalities in Alzheimer's disease, arterial spin-labeled blood flow images in 16 contiguous 5-mm axial sections were acquired in 18 patients diagnosed with probable Alzheimer's disease and 11 age-matched controls. Blood flow images from all subjects were transformed to a standard anatomical space for voxel-by-voxel statistical analysis. High quality blood flow images were obtained from all but 1 subject. Statistical analysis demonstrated significant flow decreases relative to control subjects in temporal, parietal, frontal, and posterior cingulate cortices. Increased severity of disease, as measured by Mini-Mental State Examination, correlated with posterior parietal and posterior cingulate decreases but not temporal decreases. Arterial spin-labeled magnetic resonance imaging was found to be an effective tool for characterizing flow decreases accompanying Alzheimer's disease. The absence of ionizing radiation or injection and the ability to obtain high quality anatomical images within the same scanning session make arterial spin labeling an attractive technique for the study of Alzheimer's disease, for the evaluation of pharmacological therapies, and, possibly, for early diagnosis.

Aged↗
PubMed2000

Calcinosis cutis following the administration of intravenous calcium therapy.

Calcinosis cutis, the cutaneous deposition of calcium salts in the dermis, can occur through a variety of pathogenetic mechanisms, and can be associated with both normal and elevated calcium levels. Iatrogenic causes of calcinosis cutis include extravasation of intravenously administered calcium chloride or calcium gluconate, and traumatic deposition of calcium in the skin, subsequent to electromyography or electroencephalography. We report two cases of calcinosis cutis following intravenous infusion of a calcium-containing salt.

Adult↗
PubMed2000

A nonlinear model for mammary gland growth and regression in lactating sows.

The objective was to propose an empirical mathematical model to describe mammary gland growth and regression in lactating sows. A nonlinear dynamic model based on the logistic function was constructed, and data from 61 sows were used to illustrate the model. Sows were fed four diets with two levels of energy and of protein during lactation, and individuals were slaughtered over a 30-d period to produce a cross sectional data set on weight and composition variables from suckled mammary glands. Data (y(x)) were obtained for each day of lactation (x) and fitted by nonlinear regression. The logistic distribution function was modified for different durations of growth (f; days/gram of weight or composition) and regression (g; days/gram of weight or composition): [formula in text] where y(max) is maximum weight or composition and x(max) is day of lactation at maximum. Based on results for wet weight, for example, individually suckled mammary glands grow until between Day 21 and 28 of lactation and reach a maximum of about 500 to 600 g, depending on diet. Growth pattern of mammary glands can be described well with an asymmetric nonlinear model, using different durations for growth and regression. From this model, it was possible to estimate directly biologically important parameters: maximum weight or composition, day of lactation at maximum weight or composition, and durations of growth and regression. This model can be applied to describe mammary gland growth patterns for other species and to describe similar growth or production patterns.

Animals↗
PubMed1999

Sentence processing in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative condition that is associated with the depletion of dopamine (DA)-containing neurons in specific brain regions. This article reviews one consequence of this defect-sentence comprehension difficulty in nondemented patients with PD. The first section describes the pattern of cognitive deficits seen in patients with PD, focusing specifically on their difficulties with language processing. Subsequent sections relate the profile of cognitive impairments in PD to studies investigating compromised DA metabolism in fronto-striatal brain regions. The findings suggest that the sentence comprehension deficit in PD is due in large part to limitations in the strategic distribution of cognitive resources such as selective attention that contribute to the processing of complex material. The physiological basis for this deficit appears to be associated with the disruption of a fronto-striatal cerebral network that is compromised following degradation of the DA projection system.

Cognition Disorders↗
PubMed1999

Emotional distress in critically-injured patients three months after a potentially life-threatening accident.

A case-control study was carried out to determine why some critically-injured patients remained emotionally distressed while other critically-injured patients were found to be minimally distressed three months after a potentially life-threatening accidental injury. Cognitive processing and meaning theories suggest that psychological adjustment following a traumatizing event depends on the successful integration of the event into current or modified cognitive schema and the restoration of a sense of meaning in life. These cognitive processes may be facilitated by coping strategies that share concerns, mobilize support and reframe disturbing elements. The Global Severity Index was used to identify critically-injured patients as either emotionally distressed or minimally distressed. Bradburn's Psychological Well-Being Scale, Impact of Events Scale, the Meaning-of-Illness Questionnaire and Family Crisis-Oriented Personal Evaluation Scale were used to collect cross-sectional data from 51 critically-injured patients during face-to-face interviews 8-12 weeks after the accident. Twenty-seven emotionally distressed patients and 24 minimally distressed patients were compared on the variables of psychological well-being, cognitive processing efforts, restoring a sense of meaning in life and use of coping strategies. Descriptive statistics, ANOVA and MANOVA were used to test for significant differences between the two groups. The findings showed that emotionally distressed patients scored significantly higher on efforts to cognitively process what happened, share concerns and mobilize support. They also had difficulty acknowledging the negative effects of the accident on the self and a poorer sense of psychological well-being. In contrast, minimally distressed patients evidenced a significantly greater ability to acknowledge the negative effects on the self and a higher level of psychological well-being. The potential differences between the two groups in the magnitude of the relationships of meaning, cognitive processing and coping strategies on psychological well-being were assessed by hierarchical regression equations. Psychological well-being of minimally distressed patients was characterized by a significantly higher perception of their capabilities and strengths and by an ability to acknowledge a change in their relations with family and friends.

Adaptation, Psychological↗
PubMed1999

Persistency of lactation yield: a novel approach.

The objectives of our study were to propose a new, simple, and easy-to-understand definition for persistency of lactation yield and to develop a new mathematical model to describe a lactation curve, one that includes a measure for persistency of lactation yield according to the proposed definition. Our definition of persistency is the number of days during which the level of constant yield is maintained. No lactation model exists that includes a measure of persistency in terms of duration of time or that allows this measure of persistency to be derived from model parameters. It was necessary, therefore, to develop a new model to describe the lactation curve: [formula: see text] where yt = yield at time t, t1 = time at transition from increased yield to constant yield, yP = level of constant yield, b3 = rate of decline in yield from the end of constant yield to the end of lactation, and P = persistency of constant yield. These four parameters measured directly the important biological characteristics of a lactation curve. Two test day data sets, one for individual records from a high-producing cow and one for average records from 17,607 cows, were used to illustrate the model and to estimate persistency. The proposed measure of persistency should be important for genetic selection because it might be desirable to select for increased persistency (e.g., for extended lactations) without increasing peak yield and, hence, subjecting the cow to undesirable stress.

Animals↗
PubMed1999

Phases of alcohol problem prevention research.

We build on precedents from other health research to present a phases model of research for alcohol problem prevention that accommodates the special characteristics of this research. We propose a five-level model, in which research moves along a series of relevant continua: from basic to more and more applied research; from descriptive hypothesis-generating pilot studies to full-fledged, methodologically sophisticated, hypothesis-testing studies; from smaller to larger samples for testing; from greater to lesser control of experimental conditions; from more artificial "laboratory" environments to real-world geographically defined communities; from testing the effects of single prevention strategies to more complex studies of multiple strategies integrated into intervention systems; and from research-driven outcome studies to "demonstration" projects that evaluate the capacity of various types of communities to implement prevention programs based on prior evaluations. The five phases of research are: (1) foundational research to define and determine the prevalence of specific alcohol-involved problems, establish causal factors and processes that yield the specific problems or increase the risk of a problem, and provide the foundations for the development of effective prevention interventions; (2) developmental (preliminary effectiveness) studies to develop and test the likely effectiveness, safety, and costs of new interventions or to assess the effectiveness, safety, and costs of an existing intervention; (3) efficacy studies to determine the effects, safety, and costs of an intervention under optimal conditions of implementation (or availability or enforcement) and acceptance (or adoption at the community, organizational, or group level; or participation, compliance, or adherence at the individual level); (4) effectiveness studies of the real-world effectiveness of preventive interventions with purposeful or natural variation in implementation and acceptance; and (5) demonstration studies of the effects of interventions when widely disseminated. The proposed phases model for alcohol problem prevention research presented herein differs in significant ways from the models established by other National Institutes of Health agencies. Greater emphasis is placed on natural experiments, on methods development along the whole research continuum, on collapsing or combining research phases when appropriate, on recognizing the critical importance of behavioral parameters early as well as late in the research sequence, and on extending the research continuum to embrace diffusion and dissemination (i.e., technology transfer) studies. We also include examples of phased research in existing alcohol studies and a discussion of relevant issues, including cost, special populations, methods, and dissemination. If systematically followed, this model has the potential to contribute to wider testing and dissemination of prevention interventions of known effectiveness.

Alcohol Drinking↗
PubMed1999

MR imaging quantitation of gray matter involvement in multiple sclerosis and its correlation with disability measures and neurocognitive testing.

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) is the most common inflammatory disease of the central nervous system and manifests both physical and neurocognitive disabilities. Although predominantly a disease of the white matter, MS is also characterized by lesions in the gray matter. Previous pathologic studies have found that cortical and deep gray matter lesions comprised 5% and 4%, respectively, of total lesions. Using software for lesion detection and quantitation, our study was designed to determine MS involvement in the cortical and deep gray matter and to correlate gray matter lesion load with neurocognitive function and the Kurtzke Expanded Disability Status Scale. METHODS: Using a semiautomated segmentation algorithm that detected and delineated all possible brain MS lesions on MR images, we investigated gray matter lesion volume in 18 patients with untreated relapsing-remitting MS. Cortical and deep gray matter lesions then were correlated with the neurocognitive and physical disability measurements. RESULTS: We found that cortical gray matter lesions comprised approximately 5.7% of the total lesion volume, whereas deep gray matter lesions comprised another 4.6% in this patient cohort. No strong correlations were found between gray matter lesions and disability status or neurocognitive function. CONCLUSION: These results are similar to those found in previous pathologic studies. The cortical lesion load in cases of relapsing-remitting MS, as measured by MR imaging, represents less than 6% of the total lesion volume and does not correlate with disability measures or neurocognitive tests.

Adult↗
PubMed1998

A study of the efficacy of a comprehensive memory enhancement program in healthy elderly persons.

Well educated, high functioning older adults (ages 60-90) were given a comprehensive memory enhancement training program to determine the effectiveness of the program in increasing cognitive performance and positively influencing self-assessments of memory efficacy. The 68 subjects who participated in the memory enhancement training were compared to 74 subjects who were enrolled in a video control group. Between subject differences were analyzed prior to the interventions and at three time points following the interventions (immediately post, 3 months and 6 months). Only one cognitive measure, assessing verbal memory, revealed a significant difference between the groups, with participants in the memory enhancement group showing less decline from baseline than the video control group immediately following the intervention but with no difference between groups at 6 months post-intervention. Several self-report measures showed that the memory enhancement training subjects experienced improved memory functioning and decreased memory concerns relative to the video control group. The self-reported effects of the training were sustained over the 6-month follow-up period.

Adult↗
PubMed1998

Cognitive, neuroimaging, and pathological studies in a patient with Pick's disease.

We conducted cognitive, imaging, and neuropathological studies on a patient with Pick's disease. The patient was impaired at interpreting sentences with complex grammatical constructions, differing significantly from control subjects and patients with Alzheimer's disease (AD). Evaluation of regional brain functioning at rest, with positron emission tomography, revealed reduced left frontal activity compared with control subjects and AD patients. Autopsy demonstrated the classic pathology of Pick's disease, including massive neuron loss and gliosis in the frontal and cingulate cortex as well as numerous tau-positive hippocampal Pick bodies. The abnormal tau proteins were phosphorylated at the same amino acid residues as AD paired helical filament tau (PHFtau), but they exhibited a unique migration profile on western blot. Our observations support the hypothesis that a distinct variety of hyperphosphorylated tau in Pick's disease compromises the long-term viability of selectively vulnerable populations of neurons in frontal cortices that contribute to sentence processing.

Aged↗
PubMed1998

Sentence comprehension in Alzheimer's disease.

We asked 22 patients with Alzheimer's disease (AD) to respond to simple probes of sentences where we manipulated grammatical factors, semantic factors, and cognitive resource demands associated with a sentence. The results demonstrated limitations in the cognitive resources needed to appreciate atypical syntactic-thematic mapping relations and difficulty processing selection restrictions associated with a verb. By comparison, comprehension in AD was not influenced by the active or passive voice of a sentence. These findings are consistent with the hypothesis that impaired sentence comprehension in AD is multifactorial in nature, including difficulty processing cognitive resource and semantic aspects of sentences.

Aged↗