PubMed Health⌕ Search

Biomedical subjects

M Porter

Publications and source records attributed to M Porter.

At least 55 records · Page 3Linked to original sources
PubMed1988

The Sheehan total knee arthroplasty. A retrospective review.

Sixty Sheehan total knee arthroplasties (TKA) in 44 patients were reviewed 3.5 years following surgery. Patient mobility was improved, but only 29 knees were completely free of pain. In 18 knees there was a complaint of pain localized to the patellofemoral joint, and in five knees the pain was severe enough to require further surgery. Complications included three knees with presumed deep infection and three knees with tibial stud fractures. Aseptic loosening did not occur, although sinkage of the tibial component was observed. Revision arthroplasty was not successful mainly because of poor residual bone stock. Salvage surgery included three successful arthrodeses. The high incidence of patellofemoral problems and violation of bone stock make the current surface replacements attractive alternatives for TKA.

Adult↗
PubMed1987

Fractures of the distal radius. Intermediate and end results in relation to radiologic parameters.

The purpose of this study was to quantify the functional impairment following distal radial fractures and to identify the factors affecting prognosis. One hundred fifteen patients were assessed six months and two years following initial injury. On final assessment, subjectively, 56% had good, 39% had fair, and 5% had poor results. Median grip strength improved from 51% to 78%, range of movement from 87% to 94%, and wrist torque from 93% to 100%. Redisplacement occurred in 59%; only 33% clinically and 19% radiologically had perfect cosmetic results. Radial malunion was important functionally. Only when the dorsal angle exceeded 20 degrees or the radial angle fell below 10 degrees with a 30 degrees mean was there reduction in grip strength (p = 0.05). Comminution and intraarticular involvement predisposed to a median loss of movement of 15% and 11%, respectively (p = less than 0.05). Patients requiring physiotherapy formed a poor prognostic group. A combination of factors is responsible for poor results. Attention should be directed toward early and adequate rehabilitation of the injured hand and wrist.

Adolescent↗
PubMed1985

Clobetasol propionate versus fluocinonide creams in psoriasis and eczema.

A double-blind, parallel comparison was made of the short-term efficacy and safety of three times daily regimens of 0.05% clobetasol propionate cream and 0.05% fluocinonide cream in 114 adolescent and adult patients with psoriasis and 113 with eczema. After 2 weeks of topical applications, patients were assessed according to (1) investigators' overall judgment of clinical response, (2) degree of severity of specific signs and symptoms, and (3) patients' evaluation of improvement. In all three response categories in psoriasis, and in two of three in eczema, clobetasol was statistically significantly superior to fluocinonide (p less than 0.05-p less than 0.001). Healing commenced more rapidly with clobetasol and there was no indication of tachyphylaxis. In contrast, the healing rate with fluocinonide slowed noticeably after the first week, and there was a greater tendency to relapse following fluocinonide treatment. Both regimens were safe: drug-related side effects were generally mild and occurred most commonly with fluocinonide therapy in eczema patients. Overall, drug-related effects occurred in 4% of patients receiving clobetasol and 12% receiving fluocinonide (p less than 0.05). Transient morning plasma cortisol reductions below 5 micrograms/dl occurred in 6% of clobetasol-treated patients, reverting to normal within 1 week of the end of treatment.

Administration, Topical↗
PubMed1984

What is, must be best: a research note on conservative or deferential responses to antenatal care provision.

During a study of innovations in antenatal care it was found that overall levels of satisfaction with care were high. Pregnant women appeared to assume that whatever arrangements they had experienced were the best arrangements possible and to be negative about innovations until they had experienced them. This response, which may be due to conservatism or deference, is examined in relation to aspects of general practice and hospital care, and its implications for the evaluation of health care are discussed.

Abdomen↗
PubMed1984

An altered beta-adrenoreceptor-mediated modulation of noradrenaline-induced vasoconstriction in spontaneously hypertensive rat mesenteric arteries.

Pressor responses to bolus injections of noradrenaline (NA) were analysed, in the isolated perfused spontaneously hypertensive (SHR) rat mesenteric arterial bed, in an attempt to investigate the beta-adrenoreceptor-mediated modulation of catecholamine-induced vasoconstriction. NA-induced responses were potentiated in the presence of timolol (10(-7) M) and suppressed by (-)isoprenaline (10(-4) M), indicating the presence of a vasodilator beta-adrenoreceptor population. The suppressant effect of (-)isoprenaline (10(-4) M) was antagonised by timolol (10(-7) M). Lower doses of (-)isoprenaline (10(-7) M - 10(-5) M) potentiated the NA-induced pressor responses, while (+)isoprenaline (10(-5) M - 10(-4) M) suppressed the NA-induced responses. It is concluded that although a vasodilator beta-adrenoreceptor population exists in the SHR mesenteric vasculature, its vasodilator function is compromised when compared to that found in normotensive rats.

Animals↗
PubMed1983

Beta-adrenoreceptor-mediated modulation of vasoconstriction in rat isolated perfused mesenteric arteries.

Pressor responses to bolus injections of noradrenaline (NA) were studied, in the isolated perfused rat mesenteric arterial bed, in the presence of beta-adrenoreceptor agonists and antagonists, in an attempt to identify a possible beta-adrenoreceptor mediated modulation of catecholamine-induced vasoconstrictor effects. NA-induced responses were potentiated in the presence of timolol and (-)propranolol and suppressed in the presence of (-)isoprenaline; (+)isoprenaline was less effective against the NA-induced responses. Timolol attenuated the effects of (-)isoprenaline on NA-induced responses but not those of the stereoisomer (+)isoprenaline. It is concluded that the NA-induced pressor effect in the rat mesenteric vasculature is the net result of vasoconstrictor alpha- and vasodilator beta-adrenoreceptor activation and that the interaction of the two opposing adrenoreceptor-mediated effects represents a 'physiological antagonism'.

Animals↗
PubMed1981

Benign coital cephalalgia. Differential diagnosis and treatment.

Benign coital cephalalgia is an acute headache that is time related to sexual intercourse. It is often confused with more serious conditions such as subarachnoid hemorrhage due to ruptured intracranial aneurysm. We describe eight patients with benign coital cephalalgia who were successfully treated with propranolol hydrochloride. We suggest that these patients have a variant of migraine.

Acute Disease↗
PubMed1981

Vesicular stomatitis virus mRNA and inhibition of translation of cellular mRNA--is there a P function in vesicular stomatitis virus?

Infection of animal cells by vesicular stomatitis virus (VSV) results in inhibition of translation of cellular mRNA. We showed previously that, in BHK cells infected by the Glasgow isolate of VSV Indiana, this is due to competition during the initiation step of protein synthesis of viral and cellular mRNA for a constant, limiting number of ribosomes. We show here that infection of the same cells with the San Juan isolate of VSV resulted in a more rapid shutoff of host protein synthesis and that this was paralleled by a more rapid accumulation of viral mRNA. Extending our conclusion that shutoff is due to mRNA competition, we show further that the average size of polysomes translating viral and cellular mRNA was threefold smaller in cells infected by VSV San Juan than by VSV Glasgow, which, in turn, was about one-half that of uninfected cells. In all cases, cellular and viral mRNA's which encoded the same-sized polypeptides were found on the same-sized polysomes, a result indicating that the efficiency of translation of both types of mRNA's is about the same in the infected cell. Also, there was no preferential sequestration of viral or cellular mRNA's in ribonucleoprotein particles. Additional correlations between the levels of viral mRNA's and the inhibition of protein synthesis came from studies of three other wild-type VSV strains and also from studies with Vero and L cells. In particular, the rate of shutoff of L-cell protein synthesis after infection by any VSV isolate was slower than that in BHK cells, and this was correlated with a slower rate of accumulation of viral mRNA. VSV temperature-sensitive mutants which synthesized, at the nonper-missive temperature, no VSV mRNA failed to inhibit synthesis of cellular proteins. Stanners and co-workers (C. P. Stanners, A. M. Francoeur, and T. Lam, Cell 11:273-281, 1977) claimed that VSV mutant R1 inhibited synthesis of L cell protein synthesis less rapidly than did its parent wild-type strain HR. They concluded that this effect was due to a mutation in an unspecified VSV protein, "P." We found, in both L and BHK cells, that R1 infection resulted in a slightly slower inhibition of cellular mRNA translation than did HR infection and that this was correlated with a slightly reduced accumulation of VSV mRNA. The level of VSV mRNA, rather than any specific VSV protein, appeared to be the key factor in determining the rate of shutoff of host protein synthesis.

Animals↗
PubMed1980

Mutants of vesicular stomatitis virus blocked at different stages in maturation of the viral glycoprotein.

Maturation of the vesicular stomatitis virus (VSV) glycoprotein (G) to the cell surface is blocked at the nonpermissive temperature in cells infected with temperature-sensitive mutants in the structural gene encoding for G. We show here that these mutants fall into two discrete classes with respect to the stage of post-translational processing at which the block occurs. In all cases the mutant glycoproteins are inserted normally into the endoplasmic reticulum membrane, receive the two-high-mannose oligosaccharides, and apparently lose the NH2-terminal signal sequence of 16 amino acids. In cells infected with one class of mutants, no further processing of the glycoprotein occurs, and we conclude that the mutant protein is blocked at a pre-Golgi stage. In cells infected with ts L511(V), however, addition of the terminal sugars galactose and sialic acid occurs normally. Thus the maturation of G proceeds through several Golgi functions but is blocked before its appearance on the cell surface. The oligosaccharide chain of ts L511(V) G, accumulated at either the permissive (where surface maturation occurs) or the nonpermissive temperature, lacks one saccharide residue, probably fucose. In addition, no fatty acid residues are added to the ts L511(V) G protein at the nonpermissive temperature, although addition does occur under permissive conditions.

Animals↗
PubMed1980

Heterogeneity of vesicular stomatitis virus particles: implications for virion assembly.

Vesicular stomatitis virus (VSV) particles formed at early times after infection contain only one-third the amount of viral glycoportein (G protein), relative to the major internal structural proteins M and N, as is found in particles released later. These "early" particles also have a lower density in equilibrium sucrose gradients than do those formed later; however, the sedimentation velocity and specific infectivity of these two classes of particles are the same. VSV-infected cells also release virus-like particles which sediment considerably faster than authentic virions and contain a higher-than-normal proportion of the VSV G protein relative to internal VSV proteins. These particles have a reduced specific infectivity but a normal density in sucrose gradients. All classes of VSV virions contain a constant proportion of M and N polypeptides. The ratio of G protein to M or N protein, in contrast, can vary over a sixfold range; this implies that an interaction between a precise number of surface G proteins with either of the underlying M and N proteins is not a prerequisite for budding of infectious viral particles from the cell surface.

Animals↗