Search PubMed⌕ Search

Biomedical subjects

M Brown

Publications and source records attributed to M Brown.

At least 289 records · Page 16Linked to original sources
PubMed1996

Complexity of age-related change in skeletal muscle.

Age-related changes in skeletal muscle mass, fiber area, and contractile function were examined in pathogen-free rats at 6, 12, 28 and 36 mos of age. The intent of this study was to clarify age-related decline, particularly in contractile force, and to determine if the decline in contractile tension with age is due to alterations at the neuromuscular junction. A variable amount of age-associated reduction in muscle mass was noted for the soleus (18%), extensor digitorum longus (EDL-16%), plantaris (37%), and gastrocnemius (38%) muscles. The decline in fiber area for these four muscles was between 5 and 16% greater than the loss in muscle wet weight. A variable amount of change in peak contractile force between 6 and 36 mos was observed for the soleus (62%), EDL (48%), and plantaris (34%). For soleus and EDL, the decline in peak tetanic tension exceeded the decline in muscle mass and fiber area. Most of the declines for the animals used in this study did not become significant until after the age of 28 mo. The marked reduction in peak tetanic tension, fiber area, and muscle mass between 28 and 36 mos indicates an accelerated age-related decline in this time period. The reduced peak twitch and peak tetanic tension in the oldest animals was not due to likely age-related changes at the neuromuscular junction. Peak values for tetanic tension were similar, whether tension was elicited via direct muscle stimulation or through stimulation of the nerve. Results underscore the complexity of age-related change and suggest that multiple mechanisms contribute to the decline of skeletal muscle.

Aging↗
PubMed1996

Detection of group C rotavirus in infants with extrahepatic biliary atresia.

The purpose of this retrospective study was to examine liver tissue from patients with cholestatic disease for the presence of group C rotavirus RNA. The reverse transcriptase-polymerase chain reaction (PCR) for genes 5 and 6 was used, and the PCR products were subjected to liquid hybridization with a 32P-labeled probe. A second amplification with nested primers was also used. Samples from 32 subjects (20 with biliary atresia or choledochal cyst and 12 controls) were tested. Ten of 20 biliary atresia patients were positive for group C rotavirus RNA; no controls were positive (P < .003). Three of the positive patients were positive for both genes 5 and 6. Six of the 10 had > 1 sample that was positive. These data suggest a possible relationship between group C rotavirus and extrahepatic biliary atresia in the 10 patients in whom virus RNA was detected.

Autoradiography↗
PubMed1996

I-131 localization in acute megakaryocytic leukemia.

A case of acute megakaryocytic leukemia in a 13-month-old infant was encountered in whom an abnormal bone scan was associated with abnormal I-131 MIBG uptake in the femoral bone marrow. The normal platelet will take up MIBG and thus, uptake of this radiopharmeceutical by the malignant megakaryocyte, a platelet precursor, may be caused by the same mechanism.

3-Iodobenzylguanidine↗
PubMed1996

Common epitope on protein VI of enteric adenoviruses from subgenera A and F.

Western blot analysis with monoclonal antibodies, produced in response to immunization with gradient-purified adenovirus 41 (Ad41) virions, identified two epitopes of interest on protein VI of enteric adenoviruses. One epitope is unique to subgenus F adenoviruses (Ad40 and Ad41); the other epitope is common to subgenus A (Ad12, 18 and 31) and subgenus F(Ad40, 41) adenoviruses but is not shared by representative serotypes of subgenera B (Ad3 and 7), C(Ad1, 2 and 5), D(Ad8) or E (Ad4). Alignment of the deduced amino acid sequence of the genes encoding the protein VI precursor (pre-VI) of Ad40 and Ad41 (subgenus F), Ad12 and Ad31 (subgenus A), Ad2 and Ad5 (subgenus C) shows that the N-terminal one-third and C-terminal 23 amino acids of pre-VI are highly conserved. Within the central domain, pre-VI of subgenus F serotypes is more closely related to that of subgenus A serotypes than to pre-VI of the non-enteric subgenus C adenoviruses (Ad2 and Ad5). By expressing random oligonucleotide fragments of the Ad41 protein VI gene as part of a T7 gene 10 fusion protein, the two epitopes of interest were mapped to within the same 14 amino acid region in the central domain of protein VI. Given the association of subgenera A and F adenoviruses with paediatric gastroenteritis, the epitope shared by these serotypes may be functionally significant with respect to gut tropism. In addition, this epitope is potentially valuable as a target for the detection of enteric adenoviruses in clinical specimens.

Adenoviruses, Human↗
PubMed1996

Analysis of the relationship between the decrease in pH and accumulation of 3-phosphoglyceric acid in developing forespores of Bacillus species.

Analysis of the pH decrease and 3-phosphoglyceric acid (3PGA) accumulation in the forespore compartment of sporulating cells of Bacillus subtilis showed that the pH decrease of 1 to 1.2 units at approximately 4 h of sporulation preceded 3PGA accumulation, as observed previously in B. megaterium. These data, as well as analysis of the forespore pH decrease in asporogenous mutants of B. subtilis, indicated that sigma G-dependent forespore transcription, but not sigma K-dependent mother cell transcription, is required for the forespore pH decrease. Further analysis of these asporogenous mutants showed an excellent correlation between the forespore pH decrease and the forespore's accumulation of 3PGA. These latter results are consistent with our previous suggestion that the decrease in forespore pH results in greatly decreased activity of phosphoglycerate mutase in the forespore, which in turn leads to 3PGA accumulation. In further support of this suggestion, we found that (i) elevating the pH of developing forespores of B. megaterium resulted in rapid utilization of the forespore's 3PGA depot and (ii) increasing forespore levels of PGM approximately 10-fold in B. subtilis resulted in a large decrease in the spore's depot of 3PGA. The B. subtilis strain with a high phosphoglycerate mutase level sporulated, and the spores germinated and went through outgrowth normally, indicating that forespore accumulation of a large 3PGA depot is not essential for these processes.

Acids↗
PubMed1996

Acute day hospitalization as an alternative to inpatient treatment.

OBJECTIVE: This paper describes the administrative process by which the Ottawa General Hospital (OGH) closed 6 beds and used the staff and space resources thus released to set up an acute day hospital (ADH) for the treatment of 8 acutely ill psychiatric patients. Outcome data are presented on the first 160 patients admitted to the ADH. METHODS: Demographic and clinical information including diagnostic (DSM-III-R; Global Assessment of Functioning [GAF]) and questionnaire data (Symptom Checklist-90 Revised [SCL-90R]; Beck Depression Inventory [BDI]; State-Trait Anxiety Inventory [STAI]; patient satisfaction) were obtained from 160 ADH patients at admission and discharge. Forty-two of these patients provided follow-up data 3 to 6 months postdischarge. The outcome of ADH patients was compared with that of a retrospectively obtained random sample (n = 100) of inpatients on selected diagnostic and demographic variables. RESULTS: On clinician-rated and self-report clinical scales, ADH patients showed significant clinical improvement reflected in higher GAF scores and less psychological distress, depression, and anxiety at discharge relative to admission. There were no significant group differences in outcome indices except for shorter length of stay in the ADH group compared with inpatients. The ADH group rated the program highly in help received and quality of service. Short-term follow-up showed that gains made during treatment were maintained 3 to 6 months later. CONCLUSIONS: These results show that a time-limited day hospital program is clinically effective for acutely ill psychiatric patients and leads to a more efficient use of inpatient resources. We believe that partial hospitalization for the treatment of acute psychiatric disorders may have wide application in psychiatric hospital practice.

Acute Disease↗
PubMed1996

Measurement of dynamic pressures at the shoe-foot interface during normal walking with various foot orthoses using the FSCAN system.

Foot orthoses are routinely used in clinical practice to redistribute pressure at the shoe-foot interface, although there is very little scientific evidence to support the efficacy of their use. In this study, the FSCAN sensor (an ultrathin in-shoe transducer) was used to determine the efficacy of pressure redistribution with a Plastizote, Spenco, cork, and a plastic foot orthosis as compared with control (no orthosis). Measurement variations of up to 18% occurred between sensors, and changes in stance time of up to 5% occurred between the orthoses and the control conditions. In spite of these potentially confounding variables, statistically significant differences in peak pressure between the orthotic types and the control condition (range, 9-146%) were noted. We conclude that Plastizote, cork, and plastic foot orthoses can be beneficial in relieving pressure in certain regions of the shoe-foot interface, but that they may do so at the cost of increasing pressure in other areas of the plantar surface.

Adult↗
PubMed1996

Mechanisms responsible for dominant expression of human growth hormone gene mutations.

Point mutations of the donor splice site of intron 3 of the human GH-1 gene cause autosomal dominant inherited isolated growth hormone deficiency (IGHD II). The mechanism by which a defect in one GH-1 allele results in GH deficiency is obscure. Previously reported reverse transcription-nested PCR data suggested an overexpression of the mutant GH-1 allele. We employed alternative methods to determine the relative expression of mutant (C for G at +1 of intron 3) and normal GH-1 allele. The use of a second round PCR primer bridging exons 2 and 3 and specific for normal GH-1 messenger ribonucleic acid (mRNA) indicated equal quantities in mutant and control cells. Large scale messenger RNA extraction from Epstein-Barr virus-transformed lymphoblasts permitted assay by ribonuclease protection. In normal pituitary, there were three GH-1 mRNA species. The variant lacking exon 3 comprised 5% of the total GH-1 mRNA. The proband's lymphoblasts contained equal amounts of mRNA with and without exon 3. Only normal GH-1 mRNA was detected in controls. Secreted GH, measured by enzyme-linked immunosorbent assay was present in equal concentrations in media from normal and mutant cells. Thus, GH-1 mRNA lacking exon 3 was expressed in proportion to the dosage of the mutant gene, and dominant effects on GH secretion were not observed in lymphoblasts. These findings are compatible with a dominant negative mechanism involving interaction between normal and mutant proteins in secretory vesicles of somatotropes.

Adolescent↗
PubMed1996

Health care 2015: flight of the butterfly.

Projecting out to the year 2015 sounds presumptuous. Who can predict that far ahead? Perhaps no one can. Social and organizational arrangements come slowly. It takes five years or so to implement simple concepts, sometimes decades for more radical changes. Once you have the ideas in tangible form, it can take another five years to get it working right. Early adopters bring others into the movement and, over 15-25 years, new directions dominate. It takes at least a generation of new practitioners to take on the new values and methods so what is likely to dominate in 2015 is beginning to be taken somewhat seriously as the successor movement to our current fad with externally imposed managed care. Put another way, entire generations of people will resist new ideas, making implementation unlikely until their control fades and a new generation takes the helm. The exciting challenge for the observer is to address the issue of where health is and should be going. Both are difficult challenges. Agreeing on what is important and what is not represents a competitive challenge. How do we perceive the world? Surely our value sets will color what we see. Who is not predisposed to select a future where they fit and their pet theories are likely to become reality. For these and other reasons, it is probably easier to agree on what we would like to see happen in the future than on what is happening. Unfortunately, unless we see the world as it is, we are less likely to be able to shift it in a direction we would like to see.

Delivery of Health Care↗
PubMed1996

Mergers, networking, and vertical integration: managed care and investor-owned hospitals.

This article links the forces of managed care and investor-owned firms as major factors driving the industry toward consolidation into vertically integrated, merged firms, often financed with investor capital. This relentless pressure to build regional systems of health services has transformed the industry from a charitable, community orientation to one of business, market shares, and profits.

Community Networks↗
PubMed1996

RNA pseudoknot modeling using intersections of stochastic context free grammars with applications to database search.

A model based on intersections of stochastic context free grammars is presented to allow for the modeling of RNA pseudoknot structures. The model runs relatively fast, having the same order running time as stochastic context free grammar parsers. The model is shown to be able to perform database searches and find RNA sequences which resemble RNA pseudoknots which bind biotin. The problem domain of RNA biotin binders has significance in the support of the RNA world model of early life on earth.

Base Sequence↗