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Biomedical subjects

M A Adams

Publications and source records attributed to M A Adams.

At least 163 records · Page 9Linked to original sources
PubMed1982

Regulation of fibrinogen synthesis by plasmin-derived fragments of fibrinogen and fibrin: an indirect feedback pathway.

The effect of plasmin-derived fibrinogen fragments on the biosynthesis of fibrinogen was investigated in cultured monolayers of rat hepatocytes. Incubating the cells with several concentrations of either fibrinogen or fibrin fragment D or E had no effect on the synthesis and secretion of fibrinogen by these cells. However, if the fragments were incubated with isolated peripheral blood leukocytes, they caused these cells to secrete a factor that when added to the hepatocytes caused an increase in fibrinogen synthesis 4- to 6-fold over controls. Moreover, the hepatocyte-stimulating factor also affected the production of several other proteins produced by the hepatocyte. These results demonstrate that both fragments D and E can stimulate hepatic fibrinogen synthesis via an indirect leukocyte-mediated pathway.

Animals↗
PubMed1982

The ethanol withdrawal syndrome in the rat: effects of drug treatment on adrenal gland and urinary catecholamines.

It has been found that a short period of severe intoxication with ethanol produces a marked reduction of adrenal catecholamines. Animals so treated demonstrate moderate to severe withdrawal signs. Accordingly, adrenal and urinary catecholamines were determined in rats undergoing withdrawal after treatment with several drugs known to modify sympathetic function. The depressant diazepam obtained withdrawal severity without altering peripheral catecholamines, propranolol reduced urinary catecholamines and transiently ameliorated withdrawal, whereas hexamethonium elevated urinary catecholamines and enhanced the severity of withdrawal. No drug treatment modified adrenal catecholamine levels. In this model the attenuation of adrenergic function has no consistent influence on the manifestation of withdrawal after ethanol.

Adrenal Glands↗
PubMed1981

An autosomal gene assignment in a marsupial: the gene for LDH-A is on chromosome 5 of the red kangaroo, Macropus rufus.

A number of somatic cell hybrids between red kangaroo (Macropus rufus) and mouse cells, which lose marsupial chromosomes, were found to express the kangaroo form of LDH-A. Concordance between the expression of marsupial LDH-A and the presence of chromosome 5 in the hybrid cells and selected subclones enabled the gene for LDH-A to be assigned to this chromosome. This is the first autosomal gene assignment in a marsupial and should prove important for chromosome mapping in the red kangaroo and in many other species of marsupials.

Animals↗
PubMed1980

The effect of posture on the role of the apophysial joints in resisting intervertebral compressive forces.

Cadaveric lumbar intervertebral joints were loaded to simulate the erect standing posture (lordosis), and the erect sitting posture (slightly flexed). The results show that, after the intervertebral disc has been reduced in height by a period of sustained loading, the apophysial joints resist about 16 per cent of the intervertebral compressive forces in the erect standing posture, whereas in the erect sitting posture they resist none. The implications of this in relationship to degenerative changes and to low backache are discussed.

Adult↗
PubMed1979

Urinary excretion of mecillinam by volunteers receiving film-coated tablets of pivmecillinam hydrochloride.

Mecillinam is a new amidinopenicillin which is taken orally as its ester pivmecillinam. 10 healthy volunteers were each given 200 mg of pivmecillinam hydrochloride four times daily and all urine was collected and cooled to -20 degrees C to minimize antibiotic degradation. 43% of the ingested antibiotic was recovered from the urine in its microbiologically active form, during the first 12 h and 34% during the subsequent 24 h. The corresponding figures for 10 volunteers receiving double this dose of antibiotic was 30 and 34%. The mean half life of mecillinam in urine due to spontaneous breakdown at 37 degrees C was 17 h. There was evidence that stearate-film-coated pivmecillinam hydrochloride tablets may be less likely to cause dyspepsia than gelatine capsules.

Administration, Oral↗
PubMed1978

Helping the parents of children with malignancy.

The parents of children with cancer experience a uniquely stressful situation that poses a profound threat to the equilibrium of the entire family. As health professionals, we recognize, with the parents, that this is a crisis and an ordeal, but that it can be resolved; we mobilize them to broaden their understanding of their situation and find constructive solutions to the problems that develop. For our patients with good prognoses, we hope to ensure a future for the whole family that is as healthy emotionally as it is physically; for those who become fatally ill, we hope to help their families support them and emerge from this experience with new adaptive abilities. Our group program is open to parents of patients who have various diagnoses, with a format that is unstructured and focuses on problems of daily living as well as the possibility of death. We have found that this is an effective approach for the delivery of mental health services to our growing population, early in the course of treatment, and for the identification of families that need ongoing counseling. Our experience with the large number of parents who have participated demonstrates that the program provides the support that the parents need and that it plays a vital role in resolving the problems that confront them as they struggle with this very difficult experience.

Death↗
PubMed1977

Growth properties of mecillinam-resistant bacterial variants in urine.

Resistant variants are often formed when susceptible Enterobacteriaceae are grown in media containing mecillinam. These variants have not yet been detected in patients or identified as a cause of treatment failure in limited clinical trials. Mecillinam-resistant organisms were formed by 5 out of 13 urinary isolates of Enterobacteriaceae incubated in urine containing mecillinam. The mean generation time of these five variants in urine containing therapeutic concentrations of mecillinam was 3.2 times that of normal organisms in antibiotic-free urine. When three of these five resistant variants were subcultured in antibiotic-free urine, the generation time, morphology, and antibiotic susceptibility returned to normal. On antibiotic-free agar medium, all five mecillinam-resistant variants readily reverted to the "susceptible" form and were therefore more likely to be phenotypic rather than genotypic mutants. In a second series of experiments, the flushing effect of the bladder on the clearance of organisms was partly simulated by frequent subculture in urine. Under these conditions, the cell density of cultures of all bacteria remained high during 10 subcultures over 52 h. However, bacterial populations progressively decreased in urine containing mecillinam until none could be detected at 28 h or thereafter. The slow growth rate of mecillinam-resistant variants may explain why detectable numbers of these organisms fail to colonize the urinary tract during treatment. Other factors may reinforce the postulated effect of the reduced growth rate in vivo.

Amdinocillin↗
PubMed1976

The relevance of growth rates in urine to the pathogenesis of urinary-tract infections due to Micrococcus subgroup 3 (Staphylococcus saprophyticus biotype 3).

A novobiocin-resistant "biotype" of Micrococcus subgroup 3 (Staphylococcus saprophyticus) is known to be a primary pathogen of the female urinary tract and to cause infections as severe as those produced by Escherichia coli. The growth characteristics of this virulent biotype were compared in vitro with those of other Micrococcaceae and of E. coli to determine whether rapid growth explains the virulence of the biotype. Nutrient broth was shown to have growth-supporting qualities that differed from those of urine and it was therefore unsuitable for these studies. In urine, the virulent biotype grew more slowly, had a longer lag period, and reached much lower final viable counts than did Escherichia coli. Surprisingly, the virulent biotype also grew more slowly and reached a lower final viable count than did several other Micrococcaceae isolated from the urinary tract of healthy women. Urine from women who had suffered a recent infection with the virulent biotype had growth-supporting properties similar to those of urine from healthy women. Experiments with filtered forestream urine suggested that urethral secretions do not contain a factor determining growth rates of this organism in urine. The possibility that virulent strains adapt to rapid growth in urine was excluded. No evidence was obtained that the virulent biotype inhibits the growth of other Micrococcaceae in urine. Ability to grow rapidly in urine does not therefore explain the virulence of novobiocin-resistant strains of subgroup-3 micrococci.

Adult↗
PubMed1976

A hospital play program: helping children with serious illness.

Children hospitalized with a life-threatening disease are experiencing a severely stressful situation that is often confusing, frightening, and anxiety-provoking. This paper describes a play-therapy program designed to facilitate the expression of these feelings, enhance the sense of mastery, foster adaptive behavior, and increase cooperation with medical treatment.

Adolescent↗
PubMed1976

Comparison of the epidemiology of bacterial resistance to mecillinam and ampicillin.

Mecillinam is a new type of beta-lactam antibiotic (an amidinopenicillanic acid) that is particularly active against Enterobacteriaceae and is taken orally as in the form of an ester, pivmecillinam. Assessment of any new antibiotic should include a survey of levels of bacterial resistance and investigation of its capacity to select resistant organisms or harm the commensal flora. Antibiotic resistance patterns of 2,000 Enterobacteriaceae isolated from the urine of patients with significant urinary tract infections were therefore determined. Mecillinam-resistant Enterobacteriaceae were found to be much less common than ampicillin-amoxycillin-resistant organisms both in the community and in hospital patients. Most ampicillin-resistant Enterobacteriaceae from infected urines were susceptible to mecillinam, but the relatively rare mecillinam-resistant organisms were usually resistant to ampicillin and cephaloridine. The fecal flora of 26 healthy volunteers who served as controls or were given repeated courses of therapeutic doses of either ampicillin or pivmecillinam was studied. Pivmecillinam had only a transient effect on the aerobic fecal flora and in contrast to ampicillin did not increase populations of resistant Enterobacteriaceae, which would be a potential hazard to the patient and contaminate the environment.

Ampicillin↗