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Biomedical subjects

R MacDonald

Publications and source records attributed to R MacDonald.

At least 73 records · Page 4Linked to original sources
PubMed1994

The endometrial ablator: a new instrument.

A thermal balloon and control system designed to produce endometrial ablation blindly is described. A latex balloon on a plastic catheter is inserted into the uterus and connected to a control unit. The unit monitors the pressure and temperature of 5% dextrose in water, which has been injected into the balloon to make it conform to the size and shape of the endometrial cavity. The balloon contains a shielded heating element that is activated to heat the liquid in the balloon to a temperature of 92C. The pressure control deactivates the heating element if the pressure falls below 45 mmHg or rises above 165 mmHg. A timer controls and measures the elapsed interval of heating. The device was tested in human uterine specimens for the potential for uterine perforation, uterine rupture, and thermal effects. Subsequently, the device was tested in six patients in Mexico and four patients in London during hysterectomy just after the abdomen was opened. Thermistor probes were placed at various loci in the uterus to monitor temperature during activation of the thermal balloon. Serosal temperatures were unchanged and endometrial temperatures rose to about 90C. The extent of uterine tissue damage was determined in Mexico City by the zone of visible coagulation of the cut wall of the uterus following removal. In London, tissue diaphorase was measured to determine the depth of destruction of the cellular oxidative enzymes. These measurements varied from 3.3-10 mm under the conditions of time and temperature used. The safety features and the potential for clinical application are discussed.

Catheter Ablation↗
PubMed1993

Characterization of a transglutaminase expressed in human pancreatic adenocarcinoma cells.

A soluble tissue type transglutaminase (TGases; R-glutaminylpeptide:amine gamma-glutamyltransferase, E.C.2.3.2.13) belonging to a group of widely distributed enzymes which catalyze the reaction between a gamma-carboxyamide group of a protein-bound glutamine residue and various amino groups was characterized in cell lines derived from human pancreatic carcinoma. The enzyme activity was measured by incorporation of [3H]putrescine into N,N-dimethylcasein. It showed a strong dependency on Ca2+, which could not be replaced by Mg2+ but was 80% inhibited by 0.7 mM Mg2+ in the presence of optimal Ca2+ concentration (7 mM). The Km-value in regard to putrescine was 2.6 mM. After centrifugation of cell homogenates at 105,000g 95% of the enzyme activity was found in the supernatant indicating that the TGase in pancreatic tumor cells is soluble. This was further substantiated by immunohistochemistry showing a homogeneous cytoplasmic distribution of the TGase in pancreatic tumor cells. Molecular sieve chromatography and Western blot analysis using an antibody against TGase II from human erythrocytes revealed a molecular mass of 80 kDa. In Northern blots with a cDNA of TGase II from mouse macrophages a single transcript approximately 3.4 kbp in size was detected. Polymerase chain reaction analysis using primers for the coding and 3'-non-coding regions showed in each case a single product with the size expected from the human cDNA of TGase II. Taken these data together, we conclude that human pancreatic adenocarcinoma cells express the soluble tissue type TGase II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Antenatal care of low risk obstetric patients by midwives. A randomised controlled trial.

OBJECTIVES: To assess the practicality, acceptability to patients and salary costs of the antenatal care of low risk obstetric patients by midwives. DESIGN: A randomised controlled trial. SETTING: The antenatal clinic at Westmead Hospital, a teaching hospital of the University of Sydney in western Sydney. PATIENTS: From January 1989 until November 1990, 89 women booking for full antenatal care at Westmead Hospital and classified as low risk were randomly allocated to one of two groups. Group 1 (43 patients) had their antenatal care provided by registered midwives. Group 2 (46 patients) had their antenatal care provided by an obstetrician (either Visiting Medical Officer or Staff Specialist) in a routine hospital antenatal clinic. INTERVENTIONS: Patients in the midwives' clinic were seen by an obstetrician at their first visit to the antenatal clinic and again at 30 weeks and at 40 weeks. MAIN OUTCOME MEASURES: These were the salary costs of each clinic and the patients' levels of satisfaction. Maternal and neonatal indicators, delivery details and analgesic requirements were also considered. These indicators were planned before data collection commenced. RESULTS: The major differences found were a 28% to 68% salary cost saving and that patients cared for by midwives showed appreciation of the continuity of care and information given at the midwives' clinic. CONCLUSIONS: The care of low risk obstetric patients by midwives in a midwives' clinic showed salary cost savings and high patient acceptance.

Continuity of Patient Care↗
PubMed1992

Diclofenac for analgesia after caesarean section.

The analgesic efficacy of a single intramuscular dose of 75 mg diclofenac given after elective Caesarean section was studied in 50 women in a double-blind randomised manner using a patient-controlled analgesia system. The mean 18 h papavaretum consumption of the placebo group was significantly greater (91.4 mg compared to 61.4 mg). Subjective experience of pain and observed sedation were significantly greater in the control group up to 6 h after operation.

Adult↗
PubMed1992

Patterns of substance use among students meeting lifetime DSM-II criteria for alcohol misuse.

A cross-sectional survey of 989 college students was conducted to investigate substance use patterns between students meeting lifetime DSM-III alcohol misuse criteria and students not meeting misuse criteria. Students meeting alcohol misuse criteria (n = 294) reported a significantly greater history of lifetime substance use and were more likely to have used marijuana in the 6 months prior to the receipt of the questionnaire. No significant differences in the frequency of substance use within the 6-month period were indicated between the two student groups with the exception of marijuana. Students meeting lifetime DSM-III alcohol misuse criteria also reported having experimented with marijuana at an earlier age.

Adolescent↗
PubMed1992

Normal birthweight at Port Moresby General Hospital: a retrospective survey of normal term births to determine birthweight distribution.

A retrospective survey was carried out of term babies born to Papua New Guinean parents at the Port Moresby General Hospital. Only babies of known gestational age from uncomplicated pregnancies who were delivered after 37 and before 42 completed weeks were included in the study. The purpose of the study was to determine the birthweight distribution at term of uncomplicated pregnancies for Papua New Guineans at the Port Moresby General Hospital. The sources of the data were the patients' case records and the labour ward register. The Epi Info V5 (CDC and WHO) statistical software package was used for the analysis. 404 subjects were studied; 116 of these were nulliparae before the index delivery. For the whole study population some of the findings were as follows: mean birthweight 3251g, standard deviation 403.5, mode 3100g, median 3250g, 10th percentile 2713g, 90th percentile 3750g. Birthweight at 41-42 weeks was significantly greater than at 37-38 completed weeks. The height and parity of the mother and sex of the baby also had significant effects on birthweight but the latest birth interval had no significant influence. Babies of highland mothers were significantly heavier than babies of Papuan mothers.

Age Factors↗
PubMed1991

Spotlight on lasers. A look at potential benefits.

Before lasers can be highly integrated into clinical practice, further research must prove the efficacy, efficiency, consistency and safety of this new technology. Currently, increased caries prevention and rapid laser etching are two potential benefits of laser technology.

Acid Etching, Dental↗
PubMed1991

Risk factors associated with alcohol abuse in college students.

A survey of 989 college students was conducted to investigate risk factors--gender, family history of alcohol abuse, family history of depression and mental illness, childhood hyperactivity, and antisocial personality-associated with alcohol abuse. Two hundred ninety-four subjects (29%) completing the alcohol subscale of the Diagnostic Interview Schedule met lifetime DSM-III criteria for alcohol abuse. Utilizing a loglinear model, expression of childhood and early adolescent deviant behavior, family history of depression, and gender were shown to be significantly associated with alcohol abuse among students.

Adult↗
PubMed1991

The alcohol use disorders identification test (AUDIT) in a college sample.

This study was conducted to estimate the psychometric properties of the questionnaire section of the Alcohol Use Disorders Identification Test (AUDIT) in a college sample using DSM-III criteria for alcohol abuse as the criterion standard. This alcohol screening test was developed for the 10 country AMETHYST project. In this young adult sample the instrument exhibited a sensitivity of .84 and specificity of .71 when utilizing the recommended cut-off score of 11. The 10-item questionnaire section of the AUDIT appears to have important advantages over other alcohol screening instruments such as the CAGE and the MAST.

Adult↗
PubMed1990

Effects of diazepam on approach, self-reported fear and psychophysiological responses in snake phobics.

The effects of diazepam was assessed on a number of measures of phobic anxiety. Snake-phobic subjects underwent two sessions on either diazepam or placebo in a crossover design. In addition to a habituation series, a slide with the phobic object was displayed as well as a live snake which subjects were asked to approach. The anxiolytic effect of diazepam was manifest in only one measure of fear, namely self-rated fear at the point of closest approach when it also attained the highest level. The result would indicate that diazepam has an anxiolytic only on high levels of subjective anxiety. The magnitude of the phasic cardiac reaction to the slide was highly and positively correlated with self-rated fear of the slide.

Adolescent↗
PubMed1990

Laser laparoscopic adhesiolysis.

Carbon dioxide laser laparoscopy offers a safe, effective, and relatively easy means of performing intraabdominal adhesiolysis. Sixty-five patients suffering from chronic lower abdominal pain have undergone laser laparoscopic adhesiolysis during the past 6 years. Fifty-three patients (84%) experienced symptomatic relief. The controversial association between abdominal pain and intraabdominal adhesions can be resolved only by performing a controlled prospective laser laparoscopic adhesiolysis study.

Abdominal Pain↗
PubMed1990

The emerging role for lasers in endodontics and other areas of dentistry.

This article focuses on the emerging role of lasers in endodontic therapy, a discipline where lasers could significantly change the way we practice. The use of the CO2 laser in caries prevention therapy and laser etching is also discussed to illustrate how the same laser can be used for other important procedures in dental practice by simply varying the exposure parameters. Lasers will have a definitive place in dentistry in the future, but to be practical, one dental laser will have to be applicable to a number of therapeutic procedures. This article discusses just such a situation relating to a wide variety of endodontic procedures, caries preventive procedures, and laser etching of enamel. Due to its very favorable absorption on dental hard tissues, the CO2 laser will also undoubtedly be useful for many other procedures in dental practice.

Carbon Dioxide↗