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Biomedical subjects

M J Smith

Publications and source records attributed to M J Smith.

At least 271 records · Page 15Linked to original sources
PubMed1989

Twenty-five years of renal trauma at a teaching hospital.

In a study of 535 patients with renal trauma admitted to the Medical College of Virginia Hospitals from 1962 to 1988, the authors found indications of a decrease in the rate of total nephrectomy in patients with blunt trauma, due in part to advances in diagnostic technology. In the cases of gunshot wounds, however, a persistently high rate of nephrectomy prevailed, reflecting, the authors believe, the proliferation of increasingly lethal weaponry.

Humans↗
PubMed1989

Altered filtrability of white blood cells after myocardial infarction.

Abnormal white blood cell rheological behaviour has been implicated as a cause of blood flow disturbances under conditions of ischaemia and reduced perfusion pressure. Accordingly, we have tested the mechanical properties of white cells following myocardial infarction by measuring the rate at which suspension of these cells cause plugging of Nuclepore filters. The number of clogging particles in a standard white cell suspension increased by the third day after infarction but subsequently decreased to the control levels. Since white cells can cause blockage of narrow blood vessels, it is assumed that such changes in cellular properties may influence the eventual extent of infarction.

Aged↗
PubMed1988

Histone genes in three sea star species: cluster arrangement, transcriptional polarity, and analyses of the flanking regions of H3 and H4 genes.

The arrangement of core histone genes and their transcriptional polarity has been determined for three species of sea stars (Pisaster ochraceus, P. brevispinus, and Dermasterias imbricata) representing two orders which diverged over 500 million years ago. Each species has approximately 500 core histones cluster repeats per haploid genome. The close phylogenetic relationship between the Pisaster species is evident from the correspondence of restriction sites in the repeat element, identical arrangement of core histones, and high degree of sequence homology in both the coding and spacer regions of the H3 gene. The Dermasterias repeat has the same gene order and transcriptional polarity of core histones, but its restriction map is significantly different. Moreover, the Dermasterias H3 gene has the same amino acid sequence, but in comparison to Pisaster nucleotide sequences, shows a high level of silent substitutions. Analyses of the nucleotide sequence of the 5' and 3' regions surrounding the H3 gene from each species demonstrate the presence of appropriately spaced consensus and processing signal segments. The 3' spacer segment of the Dermasterias H4 gene contains an unusual, threefold tandemly repeated, 21-nucleotide, AT-rich sequence. No similar sequence is seen in the P. brevispinus H4 3' region, but these two species show a striking regularity of distribution of five different homologous oligomers in the 3' spacer.

Animals↗
PubMed1988

Pelvic lipomatosis: 35-year experience.

From 1950 through 1985, 18 patients 26 to 65 years old (mean age 44.5 years) presented with pelvic lipomatosis. Followup ranged from 6 months to 17 years, with a mean of 7.5 years. Of these 18 patients 16 (89 per cent) are alive, 1 (6 per cent) died of uremia and 1 (6 per cent) was lost to followup after 6 months. During this period 7 patients (39 per cent) required operative procedures for urinary obstruction. Although pelvic lipomatosis is a benign proliferation of fat in the true pelvis that is known to lead to urinary tract, fecal and even vena caval obstruction, it also may remain dormant and cause no significant symptoms for many years.

Adult↗
PubMed1988

Role of vasopressin in regulation of sodium excretion.

It has been proposed that arginine vasopressin (AVP) contributes to the regulation of renal sodium excretion by direct intrarenal actions, by neural-hormonal interactions, and via secondary effects of fluid volume retention. The present studies were designed to determine the extent to which the natriuretic effects of AVP are secondary to volume expansion. Three groups of dogs were studied: the first was infused with AVP for 2 weeks in amounts that increased plasma levels from 3 to 15 pg/mL, while water intake was maintained constant by intravenous (iv) water infusion. The second group received the same amount of AVP and was permitted to drink ad libitum. The third group was infused with the same amount of AVP, while total body weight and volume were maintained at a constant level by use of an electronically servo-controlled water infusion system. The results showed a large increase in total body weight (+1.5 kg) and arterial pressure (mean arterial pressure (MAP); +40 mm Hg) in dogs receiving a fixed water intake. This was accompanied by a continuing natriuresis over a 2-week period and severe hyponatremia (115 mEq/L). Dogs allowed ad libitum drinking retained much less fluid (+0.5 kg). MAP was not significantly elevated, and natriuresis did not occur in this group, but hyponatremia was observed (130 mEq/L), and plasma renin activity (PRA) was suppressed. Servo-controlled dogs exhibited no change in MAP, plasma sodium, or PRA, and only a small (-15 mEq) natriuresis occurred on day 1 of AVP infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The arthropathy of cystic fibrosis.

Musculoskeletal symptoms are frequent in cystic fibrosis (CF). Here the clinical features of 29 patients with CF who had significant arthropathy are described. Twelve had episodic arthritis (EA) characterised by repeated short attacks of severe, incapacitating polyarthritis, which in seven was associated with fever and erythema nodosum. Ten patients had hypertrophic pulmonary osteoarthropathy (HPOA). The onset of symptoms in the group with HPOA was usually later (mean age 20 years v 16 years for EA) and was associated with significantly worse lung function than in patients with CF, either without arthropathy or with EA. Seven patients had arthropathies which could not be classified as EA or HPOA.

Adolescent↗
PubMed1988

The role of home care service in family care of developmentally disabled children: an exploratory study.

Recent concern about the needs of developmentally disabled children living at home has led to increased attention to family support programs. Home care service is one family support option which should be viewed as a basic fundamental support strategy. An exploratory study of a small number of families caring for developmentally disabled children in New York City indicates that publicly-funded home care produces a great number of benefits for this special population.

Adolescent↗
PubMed1987

Two regions downstream of AATAAA in the human antithrombin III gene are important for cleavage-polyadenylation.

We have investigated the sequence requirements for the cleavage-polyadenylation reaction in the human antithrombin III (ATIII) gene. A series of 5'-3' and 3'-5' deletions were produced around the AATAAA site using Bal31 nuclease. Ligation of appropriate pairs of such mutations resulted in the generation of varying sized deletions or duplications of sequences either upstream of, downstream of, or within the region encompassing the poly(A) site. Whereas a large deletion 3' to the AATAAA signal abolished cleavage and polyadenylation of ATIII transcripts, smaller deletions, all of which were subsets of the large one, did not. This indicated that the ATIII gene contains at least two independently acting poly(A)-cleavage signals 3' of AATAAA. When one of these signals was eliminated and the other was partially deleted at its 3'-end, we were able to disrupt the normal spacing between AATAAA and the cleavage site without substantially affecting the efficiency of the cleavage reaction. This suggested that the distance between AATAAA and the cleavage site is determined by the same sequence which, along with AATAAA, specifies cleavage and polyadenylation. The duplication of regions either upstream or downstream of AATAAA affected neither the efficiency nor the site of cleavage of the ATIII transcript. When a duplication included a large region containing AATAAA as well as downstream sequences, both sites were chosen for cleavage reactions. With a more delimited duplication, which included AATAAA but not the downstream cleavage signals, both sites were again used. However, two new cleavage sites were now detected. These results suggested that the distance between AATAAA sites and critical downstream cleavage-spacing sequences may also be important in determining the site of cleavage. This may in part stem from spatial constraints imposed by RNA-protein complexes which have been postulated to be critical in catalyzing the cleavage-polyadenylation reaction.

Antithrombin III↗