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Biomedical subjects

M J Bennett

Publications and source records attributed to M J Bennett.

At least 253 records · Page 14Linked to original sources
PubMed1984

Simpler liquid-chromatographic screening for organic acid disorders.

We describe an isocratic cation-exchange chromatographic technique, with ultraviolet detection, for determination of urinary organic acids. The method is useful for screening urines from neonates and infants suspected of having an organic aciduria, prior to confirmatory analysis by gas chromatography-mass spectrometry. Advantages of this technique over conventional gas chromatography include ease of sample preparation and the simultaneous detection of volatile fatty acids; limitations include its lack of an identification system like that of mass spectrometry, the presence of nonultraviolet-absorbing fatty acids, and the relatively long retention times of phenolic compounds. Chromatograms for patients with methylmalonic aciduria, propionic aciduria, isovaleric aciduria, beta-ketothiolase deficiency, lactic aciduria, and glutaric aciduria type II are compared with those for a normal infant.

Adult↗
PubMed1983

Induction of labour in pregnancy complicated by heart disease.

Thirty-seven patients whose pregnancies were complicated by heart disease and who required induction of labour were given 4 mg of prostaglandin E2 (PGE2) oral tablets per vaginam. Thirty-one patients (84%) went into labour and delivered within 24 hours, 28 of them vaginally. Although 3 infants had an Agpar score of less than 7 at birth, 2 having been delivered vaginally, all were discharged from hospital thriving and in good condition. No side-effects of PGE2 were observed and although these women had a wide range of functional disabilities, none developed deterioration in cardiac status. Vaginal administration of PGE2 for induction of labour is a safe and simple method of achieving elective delivery in patients with pregnancies complicated by heart disease.

Dinoprostone↗
PubMed1983

Focal psychotherapy--terminable and interminable.

Despite evidence that many patients use psychotherapy intermittently at times of need, most treatment is structured as though it had a clear beginning, middle, and end. The aim is to treat an identified area of psychopathology. This article presents an alternative model, in which the patient is seen as evolving, receptive to and needing different interventions at different times. Treatment consists of episodes of focal therapy within the framework of an enduring helping relationship, akin to the practice of primary medical care. Since he can call upon the therapist repeatedly if necessary, it is the patient who determines, empirically, the ultimate pattern of care. The person of the therapist serves to bridge the discontinuous contacts, allowing some patients who require the presence of a therapist in their lives over an extended period of time (a transitional phase or longer) to assure this advantage without incurring the risks or costs of uninterrupted extended treatment.

Female↗
PubMed1983

Osmotic blood-brain barrier modification: clinical documentation by enhanced CT scanning and/or radionuclide brain scanning.

Results of initial clinical trials of brain tumor chemotherapy after osmotic blood-brain barrier disruption are promising. In general, the procedure is well tolerated. The major complication has been seizures. In this report, data are presented which indicate that the etiology of these seizures is related to the use of contrast agent (meglumine iothalamate) to monitor barrier modification. A series of 19 patients underwent a total of 85 barrier modification procedures. Documentation of barrier disruption was monitored by contrast-enhanced computed tomographic (CT) scanning, radionuclide brain scanning, or a combination of both techniques. In 56 procedures (19 patients) monitored by enhanced CT, seizures occurred a total of 10 times in eight patients. Twenty-three barrier modification procedures (in nine of these 19 patients) documented by nuclear brain scans alone, however, resulted in only one focal motor seizure in each of two patients. In eight of the 19 patients who had seizures after barrier disruption and enhanced CT scan, four subsequently had repeat procedures monitored by radionuclide scan alone. In only one of these patients was further seizure activity noted; a single focal motor seizure was observed. Clearly, the radionuclide brain scan does not have the sensitivity and spatial resolution of enhanced CT, but at present it appears safer to monitor barrier modification by this method and to follow tumor growth between barrier modifications by enhanced CT. Four illustrative cases showing methods, problems, and promising results are presented.

Adult↗
PubMed1983

Anesthesia for laser surgery.

Laser surgery offers several advantages to the surgeon and patient: microscopic precision, a bloodless operative field, and complete sterility. While the majority of procedures pose few problems beyond protection of the eyes of operating room personnel and patients, microlaryngeal surgery with the CO2 laser requires very careful anesthetic management. A preoperative visit to determine the degree of existing airway obstruction is mandatory in deciding the safest anesthetic technique. Continued communication and cooperation between the surgeon and anesthesiologist throughout the procedure will help minimize the conflicting needs for airway access and ventilation. We feel the best approach to the anesthetic management of patients undergoing laser airway surgery is to have several alternatives available at the time of induction of anesthesia. For adult patients wrapped tubes, metal tubes, and a jet injector should be on hand. The options are more limited in children. The smallest metal tubes available have external diameters of 6 mm (Norton tube) or 7 mm (Porch tube), which are too large to use in these younger patients. Small wrapped, uncuffed tubes or Venturi ventilation through a small-gauge needle are most often used. Regardless of the technique, constant vigilance throughout the procedure is required to detect complications early. Wrapped tubes, metal tubes, insufflation using no tube, and jet ventilation using a needle or metal tube reduce the fire hazard but each method substitutes its own set of problems. Before adopting any approach, we strongly recommend that the equipment selected be tested for flammability with the laser before its use in patients. If, in spite of precautions, ignition of equipment does occur, immediately interrupt the flow of oxygen and nitrous oxide as most materials do not burn readily in air. Then remove the offending material. We have reviewed selected aspects of the management of the patient undergoing laser surgery, outlined the principles of laser technology, and listed the many surgical procedures employing lasers. Also, recommendations on anesthetic management of microlaryngeal surgery with the CO2 laser with emphasis on currently available measures to prevent problems were reviewed in light of our own experience with this technique along with a summary of the literature on laser surgery. An understanding of the fundamental principles and applications of lasers will hopefully lead to safer patient care.

Anesthesia↗
PubMed1982

Radioimmunoassay of thyroxine and 3,3',5'-triiodothyronine (reverse T3) in human amniotic fluid.

Measurement of amniotic fluid iodothyronine concentrations may enable antenatal detection of fetal thyroid abnormalities; however, the delineation of normal ranges is complicated by methodological problems associated with strong and highly variable protein-binding, and specificity of antisera. Improved radioimmunoassays of thyroxine (T4) and 3,3',5-triiodothyronine (reverse T3, rT3) have been developed to overcome these problems. In normal pregnancy, mean rT3 concentrations at less than 17 weeks, 17-22 weeks and 35-42 weeks gestation were 3.6 nmol/l (n = 21), 6.1 nmol/1 (n = 14) and 0.66 nmol/1 (n = 39) respectively; corresponding mean T4 concentrations were 2.4 nmol/1, 6.5 nmol/1 and 3.6 nmol/1. rT3 concentrations showed a strong positive correlation with T4 concentration in each age range; however, the molar ratio of rT3:T4 decreased progressively with gestational age, from 1.69 at less than 17 weeks to 0.19 at 35-42 weeks. In both mid- and late gestation, rT3 and T4 concentrations were strongly correlated with total amniotic fluid protein concentrations.

Amniotic Fluid↗
PubMed1982

T-lymphoblastic leukaemia and aspartate aminotransferase.

AST levels from 11 untreated children with T-ALL were found to be significantly higher than those from 74 children with non-T disease. The enzyme was not related to haemoglobin or bilirubin levels nor to the presence of hepatosplenomegaly in any of the patients. It was correlated with the white cell count, but only in the T-cell group and not the remainder. It was also correlated with a parallel (but lesser) rise in ALT, but again only in the T-cell group. The blast cells themselves contained little or no transaminase activity, so it is probable that T-ALL produces more extramedullary tissue damage than non-T disease.

Alanine Transaminase↗
PubMed1982

Newborn acoustic reflexes to noise and pure-tone signals.

A variable-frequency probe-tone acoustic-impedance bridge has been developed to enable an artifact-free pure-tone acoustic reflex study to be carried out on neonates. Contralateral reflex thresholds for pure tones, broadband noise, and filtered noise were measured in 28 newborns aged 4-8 days. The mean reflex threshold for the broadband noise was 73 dB SPL, 4 dB lower than the reflex threshold for the 2600-Hz low- and high-pass noise bands. Reflex activation at 500, 1000, 2000, and 4000 Hz gave responses that closely followed the normal adult pattern although reflex thresholds were approximately 10 dB higher. Two infants failed to demonstrate reflexes. One of these failed a behavioral-response test using the Auditory Response Cradle and was found to have mild jaundice. The second infant passed the behavioral test and had measurable reflexes 5 weeks later. A third baby with elevated reflex thresholds also was jaundiced but had normal behavioral responses and was discharged. Discussion of these results emphasizes their value to those engaged in neonatal auditory assessment.

Hearing Tests↗
PubMed1982

Medical teaching--help or hindrance?

This paper describes an ongoing research study into the learning practices of medical students. Responses from structured interviews for forty-four (20%) first-year students at the University of New South Wales indicate that they work long hours, use few resources, consult little with teaching staff, co-operate a lot with each other and see themselves as responsible for their own learning. It is suggested that teacher training activities should take more notice of the actual learning practices of students if teachers and students are not to become confused and disillusioned.

Australia↗
PubMed1982

Predictive value of ultrasound measurement in early pregnancy: a randomized controlled trial.

Early fetal biparietal diameter (BPD) measurements were obtained with ultrasound in 1062 women attending for antenatal care; a random half had the results withheld from the obstetricians. Of the 1026 women who were sure of the dates of their last normal menstrual period, 829 (81%) were found to have appropriate biparietal diameter measurements, in 3% the pregnancy was more than 2 weeks further advanced and in 14% more than 2 weeks less than calculated. In 30% of the women whose results were intended to be withheld, the code had to be broken because of clinical concern. There were no differences in fetal outcome (birthweight centile, Apgar score at 1 min and perinatal mortality) in the women whose BPD results were known compared with those whose results were withheld from the obstetrician. But a significantly larger number of labours were induced for suspected growth retardation when the gestational age was known.

Clinical Trials as Topic↗