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Biomedical subjects

M Dudley

Publications and source records attributed to M Dudley.

15 recordsLinked to original sources
PubMed1992

Youth suicide in New South Wales: urban-rural trends.

OBJECTIVE: The study tested the hypotheses that (i) the rate of suicide by firearms among youth (aged 10-19 years) is increasing at a greater rate than rates of suicide by other methods; (ii) the rate of youth suicide in rural New South Wales is significantly higher than those in urban areas; and (iii) the increase in youth suicide by means of firearms is occurring at a greater rate in rural males aged 15-19 years than in other groups. DESIGN: Data were obtained from the NSW Office of the Australian Bureau of Statistics concerning 735 youth suicides in NSW between 1964 and 1988. These were reviewed for information concerning residential area and method of death. Five five-year periods were used, and rates were calculated with population figures obtained in the census years for the same age and sex group. RESULTS: From 1964 to 1988, suicide by firearms has risen most substantially, from 3.4 to 5.6 per 100,000 per year in 15-19-year-old males. There has also been a substantial increase in 15-19-year-old male suicides by hanging (0.7 to 3.4 per 100,000 per year). Poisoning suicides have declined among females and males in the past 15 years. Suicide rates in Sydney, Newcastle and Wollongong have remained stable. In rural cities, they have increased from 1.5 to 4.7 per 100,000 per year (F = 4.9, P less than 0.02) while in rural municipalities and shires they have increased from 1.3 to 6.4 (F = 14.6, P less than 0.0001). The suicide rate of 15-19-year-old males has shown a modest increase in Sydney and no change in Newcastle or Wollongong, but the rate for 15-19-year-old males in rural cities has more than doubled, from 5.1 to 12.5 (F = 7.7, P less than 0.003), while in rural municipalities and shires, the rate has increased more than fivefold, from 3.9 to 20.7 (F = 9.3, P less than 0.001). There has been no significant change in the suicide rates of 15-19-year-old females, or in 10-14-year-olds. The rate of suicide by firearms among 15-19-year-old males has not risen significantly in rural cities, but in rural municipalities and shires the rates have risen fivefold from 2.8 to 14.8 (F = 5.6, P less than 0.01). CONCLUSIONS: Each hypothesis was confirmed. An increase of this magnitude is not an artefact of coroners' verdicts. The findings are believed to be due to ready access to firearms, the use of alcohol and drugs (particularly in firearms suicides) and increasing socioeconomic, health, and identity problems for rural youth, especially males.

Adolescent↗
PubMed1991

Serum concentrations and safety of single daily dosing of amikacin in children undergoing bone marrow transplantation.

The serum concentrations and safety of single daily dosing of amikacin were studied in 16 episodes of fever and granulocytopenia in children undergoing bone marrow transplantation. Amikacin (20 mg/kg) was administered as a 20 min iv infusion once daily for 7 to 19 days; all patients received concomitant therapy with ceftazidime. Peak amikacin concentrations measured immediately after infusion on day 1 and 4 of therapy averaged 72.29 +/- 11.6 mg/l and 74.02 +/- 19.29 mg/l respectively. A slight but statistically significant increase 30 minute post-infusion concentrations was observed in most patients during therapy. Serum amikacin were less than 3 mg/l in all trough samples and within 6 h post-infusion in most patients. A significant increase in serum creatinine was observed in one patient, who was also receiving cyclosporin A. Auditory function was evaluated in 10 patients and showed no changes. Although other drugs were added to cover Gram-positive or fungal pathogens, all patients survived. These data combined with the recent experience of single daily dose amikacin in adults supports further evaluation of novel dosage regimens of aminoglycosides in children.

Adolescent↗
PubMed1991

The effect of a heterochronic mutation, Teopod2, on the cell lineage of the maize shoot.

Teopod2 (Tp2) is a semi-dominant mutation of maize that prolongs the expression of characteristics normally confined to the juvenile phase of development. Two of the many dramatic morphological effects of this mutation are an increase in the number of vegetative nodes, and a reduction in the overall size of the shoot. To determine the cellular basis of these phenotypes, the technique of clonal analysis was used to compare the cell division patterns of wild-type and Tp2 plants. Our results indicate that Tp2 increases the number of vegetative nodes produced by the apicalmost cells in the meristem but does not affect the cell lineage of the basal, juvenile, part of the shoot. This result demonstrates that Tp2 does not act uniquely in a 'juvenile' domain of the meristem, but instead causes cells that are normally destined to produce adult structures to express juvenile traits inappropriately. Clonal analysis also demonstrates that Tp2 does not affect the size of the meristem prior to germination, nor does it affect the cell lineage of the basic structural unit of the stem, the phytomer. Thus the effects of this mutation on the size of the shoot are the result of changes in cell fate late in development.

Cloning, Molecular↗
PubMed1989

Altered methadone pharmacokinetics in pregnancy: implications for dosing.

Lower plasma methadone levels have been reported in pregnant women receiving methadone maintenance for heroin addiction. Methadone pharmacokinetics was examined in a 24-year-old woman 8 months pregnant with twins, who experienced severe withdrawal symptoms beginning 10-12 hours after her daily 30 mg methadone dose. Methadone plasma concentration-time data were fit to a one-compartment pharmacokinetic model by extended least-squares regression. Estimated half-life for methadone was 8.1 hours, which is much shorter than the usual methadone half-life (greater than 24 hours). Plasma methadone concentrations were estimated for the cases of a) increasing the 30 mg methadone dose by 50% and administering it once daily and b) continuing the 30 mg methadone dose but administering it at 12-hour intervals. Although the model is derived from a single subject, the simulations performed clearly suggest a need for altered methadone dosing in pregnancy. More sustained plasma methadone levels are achieved with twice-daily dosing of methadone than are achieved by administering an increased methadone dose once daily. Twice-daily dosing would be expected to produce fewer withdrawal symptoms and, ultimately, improved compliance with treatment.

Adult↗
PubMed1988

Psychological dysfunction in psychiatric and general nurse trainees.

The often held belief that psychiatric professionals are more psychologically disturbed than similar non-psychiatric professionals was not supported by the present study. Indeed in a comparison of two groups of nurse trainees, general nurse trainees showed a small but significantly greater degree of psychopathology than psychiatric nurses. When confounding variables and social desirability response set was taken into account, general nurse trainees had significantly higher scores on neuroticism, trait and state anxiety and depression. The groups did not differ on psychoticism (antisocial traits), extraversion, hypochondriasis or, work or social impairment. In terms of use of illicit drugs, the psychiatric nurses used only more cannabis than general nurses which was accounted for by females alone.

Adaptation, Psychological↗
PubMed1986

In vitro models for the study of combination antibiotic therapy in neutropenic patients.

Neutropenic patients are at risk of serious infection caused by gram-negative bacilli and staphylococci. The mortality rate associated with gram-negative bacteremia in these patients is extremely high, especially in those with persistent and profound granulocytopenia. In these latter patients, the best results have been obtained by administering combinations of antibiotics in which both agents are active and/or show in vitro synergism against the infecting organism. Most combinations include an aminoglycoside such as amikacin and a broad-spectrum beta-lactam antibiotic, such as azlocillin, mezlocillin, piperacillin, or ceftazidime. The International Antimicrobial Therapy Project Group of the European Organization for Research and Treatment of Cancer has completed several studies evaluating various antibiotic combinations in the empiric treatment of febrile neutropenic patients. These trials have evaluated cephalothin plus gentamicin, carbenicillin plus gentamicin, and cephalothin plus carbenicillin; carbenicillin plus amikacin and carbenicillin plus amikacin plus cefazolin; azlocillin plus amikacin, ticarcillin plus amikacin, and cefotaxime plus amikacin; and azlocillin plus amikacin versus ceftazidime plus long- or short-course amikacin. The preclinical evaluation of antibiotic combinations usually involves the in vitro testing of antibiotics alone and in combination by the checkerboard method or with the use of time-kill curves. However, these methods expose the bacterial culture to a static or constant concentration of the drugs. During the in vivo treatment of infections, bacteria are exposed to changing concentrations of antibiotics, which are contingent on the individual pharmacokinetics of these drugs. We have designed a two-compartment in vitro pharmacokinetic model that allows the simultaneous study of the activity of two antibiotics with similar or different half-lives against a number of bacteria. Amikacin and azlocillin have been studied alone and in combination in this model against Pseudomonas aeruginosa, a frequent cause of bacteremia in neutropenic patients. In pharmacologically relevant doses, amikacin alone produced rapid bacterial killing, followed by regrowth of resistant subpopulations. Azlocillin alone produced a more gradual reduction of the bacterial inoculum, with ultimate bacteriostasis. Amikacin plus azlocillin produced rapid and complete eradication of the organism. In vitro pharmacokinetic models may prove to be more predictive of clinical outcome than are traditional static in vitro methods used to study antibiotic combinations.

Agranulocytosis↗
PubMed1984

Group cognitive/anxiety management.

A report on recent clinical work in group anxiety management was carried out by nurse therapists whilst undertaking the Joint Board of Clinical Nursing Studies Course 650, Adult Behavioural Psychotherapy (Short Term) in the Plymouth area, England. The group treatments described were based upon a three systems model of anxiety, and aimed to modify cognitive, behavioural and physiological deficits and excesses. The methods used and some collation of measures is shown, followed by discussion of the difficulties encountered. This discussion will relate to: the uses of measures; style of presentation of material, particularly in relation to cognitive change; and adaptability and scope of such groups.

Adult↗
PubMed1983

Clinical evaluation of new AMS GSC plus card.

The AutoMicrobic System GSC Plus Card was compared to a broth microdilution reference method. Of 1660 minimum inhibitory concentration pairs, 86.1% were within 1 log2 dilution range. A total of 89.2% of the GSC Plus results agreed qualitatively (susceptible, moderately susceptible, resistant). If chloramphenicol data are excluded, agreement is 88.8% and 89.9%, respectively. A total of only 0.90% results were very major or major discrepancies. This is significantly fewer major discrepancies than reported with other systems.

Anti-Bacterial Agents↗