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Biomedical subjects

J Hamilton

Publications and source records attributed to J Hamilton.

At least 181 records · Page 10Linked to original sources
PubMed1986

A prospective study of inhibitive casting as an adjunct to physiotherapy for cerebral-palsied children.

The effect of a three-week course of inhibitive casting and neurodevelopmental therapy on the static muscle tonus, developmental skills, passive range of ankle dorsiflexion and gait pattern was determined in 32 cerebral-palsied children. Two weeks after treatment, passive range of ankle dorsiflexion and foot-floor contact in walking had improved significantly but there was no significant change in the static muscle tone or developmental skills. After five months the improvements in ankle dorsiflexion and walking pattern were no longer evident. Further objective studies to determine the effect of 'inhibitive casting' are necessary before the modality is used indiscriminately.

Ankle↗
PubMed1986

Platelet interaction with a pancreatic ascites tumor.

The mechanism leading to the hypercoagulability in pancreatic carcinoma is unclear. The rapid progress of the disease after its diagnosis and the inaccessibility of the tumor make studies on the mechanism difficult in man. With the successful induction of this malignancy and conversion of it into an ascites tumor in Syrian golden hamsters, interactions between isolated tumor cells and individual hemostatic components can be investigated. In this paper, studies on in vitro tumor cell-platelet interactions and some hemostatic changes in hamsters following intravenous injection of isolated tumor cells are described. Freshly isolated tumor cells and tumor-cell sonicates, but not those that had been kept at 4 or -70 C overnight, induced comparable aggregation of human platelets in both heparinized and citrated platelet-rich plasmas (hPRP and cPRP). The aggregation was not followed by clot formation; a specific synthetic thrombin inhibitor had no effect on the aggregation in either hPRP or cPRP. Washed and gel-filtered platelets, even in the presence of 5% of citrated or heparinized platelet-poor plasma (cPPP or hPPP) failed to be aggregated by tumor cells. Tumor-cell-induced platelet aggregation was accompanied by thromboxane formation and serotonin release, both of which were several orders of magnitude greater in cPPP than in hPRP. Aspirin, apyrase, and PGI2 all inhibited tumor-cell-induced platelet aggregation in both PRPs, but the inhibition by aspirin was minimal. Intravenous infusion of isolated tumor cells into normal hamsters resulted in a 50% reduction of platelet count and a 20-30% decline in antithrombin III and fibrinogen. Platelet aggregates and fibrin strands were seen in the lungs of these animals.

Animals↗
PubMed1985

Auditory hallucinations in nonverbal quadriplegics.

When a system for communicating with nonverbal, quadriplegic, institutionalized residents was developed, it was discovered that many were experiencing auditory hallucinations. Nine cases are presented in this study. The "voices" described have many similar characteristics, the primary one being that they give authoritarian commands that tell the residents how to behave and to which the residents feel compelled to respond. Both the relationship of this phenomenon to the theoretical work of Julian Jaynes and its effect on the lives of the residents are discussed.

Adult↗
PubMed1985

Multicenter seroepidemiologic study of the impact of cytomegalovirus infection on renal transplantation.

The effects of cytomegalovirus (CMV) infection on patient and allograft survival were determined in 1245 renal transplant recipients from 46 transplant centers. When an antilymphocyte preparation was administered to cadaveric allograft recipients, those at risk for primary CMV had a worse outcome than similar patients treated with prednisone and azathioprine (53.1% alive at 6 months with a functioning allograft vs. 70.8%, P = .05) or patients at risk for reactivation CMV (53.1% vs. 71.1%, P = .035). Patients at risk for reactivation CMV had a better outcome if they received an antilymphocyte preparation (71.1% vs. 60.8%, P less than .01). The type of immunosuppression had no effect on patients without CMV. Living-related donor transplantation was not significantly influenced by CMV or type of immunosuppression. We conclude that CMV infection is strongly influenced by the form of immunosuppression employed, and that both are important determinants of the outcome of cadaveric renal transplantation.

Age Factors↗
PubMed1985

Carnitine and carnitine transferases in the intestinal mucosa of suckling rats.

Carnitine acetyltransferase and palmitoyltransferase activity in the mucosa of the small intestine of rats rises after birth and falls at the time of weaning. The carnitine contents of the mucosa (free, acetyl-, palmitoyl- and total) decrease postnatally, reaching adult levels at the time of weaning. Orally administered 14C-carnitine is only slowly absorbed so that radioactivity is still high in plasma and organs 6 h later, whereas label given subcutaneously disappears from the plasma and tissues more rapidly. The intestinal mucosa also takes up carnitine from 14C-carnitine administered subcutaneously. It is concluded that carnitine plays an important role in the gut of suckling rats.

Acetyltransferases↗
PubMed1984

Alpha-adrenergic-induced changes in hamster (Mesocricetus) brown adipocyte respiration and membrane potential.

Respiratory rates of brown adipocytes were stimulated by 10 microM phenylephrine, the magnitude of this stimulation being about only one-third that evoked by 1 microM isoproterenol, or norepinephrine. The smaller thermogenic response to phenylephrine did not reflect limited substrate availability as shown by the finding that respiration with phenylephrine plus butyrate was not greater than that with phenylephrine or butyrate alone. These data also imply that the thermogenic response to the alpha-agonist does not involve a significant degree of mitochondrial uncoupling. Examination of in vivo changes in brown adipocyte membrane potentials indicated that phenylephrine and isoproterenol can each elicit multiphasic responses (i.e. depolarization followed by hyperpolarization and a second depolarization), although the magnitude and duration of each phase differed for the two agonists. The initial depolarization occurring within seconds after norepinephrine injection appears to result primarily from activation of alpha-adrenergic receptors, with a small contribution from the beta-pathway. Similarly, the subsequent hyperpolarization and second depolarization primarily reflect events associated with the activated beta-adrenergic pathway, with a modest contribution from alpha-mediated events.

Adipose Tissue, Brown↗
PubMed1984

Withdrawal phenomena in subjects with essential hypertension on clonidine or tiamenidine.

The incidence and pathogenesis of withdrawal phenomena with the centrally acting drugs clonidine (CLON) and tiamenidine (TIAM) were evaluated. Thirty subjects with hypertension on hydrochlorothiazide (HCTZ) were randomized to TIAM or CLON. Blood pressure and integrated plasma catecholamine levels fell equally in response to both drugs. On withdrawal, blood pressure and pulse rose in both groups with no difference between them. Three subjects had symptoms of withdrawal, four had blood pressure overshoot above pretreatment levels of 10 mm Hg or more, and eight had a rise in blood pressure of 30 mm Hg systolic or 20 mm Hg diastolic. There was no difference between TIAM and CLON in these effects. There was a direct correlation between blood pressure rise and increase in integrated plasma norepinephrine levels. We conclude that the incidence of withdrawal phenomena in subjects on TIAM or CLON is infrequent and that there is a direct relationship between the rise in blood pressure and the loss of suppression of catecholamines by these drugs.

Adult↗
PubMed1984

Analysis of emotional status during the hospital treatment of a borderline patient.

This single case study illustrates a methodology for identifying recurrent pathological emotional states in a hospitalized, borderline patient. Parallel therapeutic inputs are delineated and examined in terms of patient-specific responses. The results indicate that ratings of nursing notes recorded across three periods of hospitalization can reliably isolate the patient's most salient and debilitating emotional states. State-specific therapeutic interventions are extracted and their effectiveness noted. The analyses illustrate clinical phenomena which are congruent with what is known about borderline symptomatology. In addition, the study locates therapeutic errors which often occur when working with difficult patients.

Adult↗
PubMed1983

Presleep cognitions and attributions in sleep-onset insomnia.

This research examined the role of cognitive factors (attributions about the causes of sleep difficulties and presleep cognitive activity) in sleep-onset insomnia. Thirty-four subjects, including 13 mild to extreme insomniacs, were interviewed and then spent 5 consecutive nights in a sleep laboratory. In a multiple regression paradigm predictor measures included attribution ratings of sleep difficulty, perceived control of presleep cognitive content, and affect associated with presleep cognitions. Criterion measures included laboratory measured objectives and subjective sleep-onset latency, a score presenting the difference between objective and subjective laboratory measures of sleep-onset latency, interview-measured subjective sleep-onset latency, and degree of overall concern and presleep concern about initiating sleep. The results of multiple regression analyses suggested that the content of presleep cognitions and the attributions of sleep difficulties were significantly associated with several subjective measures of sleep-onset latency or concern with initiating sleep. None of the predictor measures was significantly associated with objectively measured sleep-onset latency. Implications for cognitive theories of sleep-onset insomnia and for the psychophysiologic-subjective dimension of insomnia are discussed.

Adolescent↗
PubMed1983

Cardiac arrhythmias after abrupt clonidine withdrawal.

Abrupt clonidine withdrawal may be associated with sharp marked increases in catecholamine levels, heart rate, and blood pressure, which may induce nausea, vomiting, and palpitations. Relatively little information is available on the incidence of cardiac arrhythmias in this setting. With continuous ambulatory ECG recordings, we determined the incidence of arrhythmias in seven male hypertensive patients (without active heart disease) after abrupt clonidine withdrawal. Serious ventricular arrhythmias, including brief ventricular tachycardia, developed in two patients who had greater increases in mean systolic blood pressure (28 +/- 3 vs 10 +/- 8 mm Hg) and double product (552 +/- 681 vs 333 +/- 195) than the others. The differences were not significant. Ventricular arrhythmias were not related to age, dose, withdrawal symptoms, initial blood pressure, urinary norepinephrine levels, or ECG abnormalities. We conclude that serious ventricular arrhythmias may be relatively common but unpredictable during clonidine withdrawal, even in patients with no clinically apparent heart disease. The triggering of ventricular arrhythmias should be added to the list of components of clonidine withdrawal syndrome.

Adult↗
PubMed1983

Group meetings for parents in a children's burns unit.

Thermal injuries in childhood occur mainly in the first three years of life and often lead to hospital admission: most are due to scalds in the home. The distress and anxiety of parents bears on the management of the young sick child in hospital, on his subsequent recovery at home and on the welfare of the whole family. To help parents, a weekly meeting was held with a small group of staff in the Burns Unit at which there was free and open discussion of all problems and worries connected with the child's accident. This paper describes the working of the group and the contribution it made to the care of 149 children admitted with burns and scalds during one year.

Burn Units↗
PubMed1982

Pulmonary function in hypertensive patients treated with pindolol: a report of two studies.

Pulmonary function was measured serially in two separate randomized trials of pindolol in the treatment of essential hypertension. Patients with overt obstructive airways disease were excluded. In study 1, 131 hypertensive patients were randomized to placebo (31) and 15 mg (33), 30 mg (33), and 60 mg (34) of pindolol. Pulmonary function was measured before and at weeks 8 and 15 of active medication. Bronchospasm--a 20% increase in forced expiratory volume in 1 second (FEV1) after isoprenaline--developed in three patients on active treatment and one on placebo. In eight patients on pindolol and one on placebo, bronchospasm ceased. Compared to placebo, no deterioration in pulmonary function occurred with pindolol and in three tests--maximum voluntary ventilation (MVV) (L/min), MVV%, midexpiratory flow rate (MEFR) (L/min)--significant improvement occurred. In study 2, 14 hypertensive patients were randomized to pindolol (mean dose 50 mg/day), 15 to propranolol (mean 360 mg/day), and 14 to chlorthalidone (mean 107 mg/day). Pulmonary function was measured after 3 weeks of placebo and again after 6 weeks of active treatment. While propranolol produced slight deterioration in pulmonary function, pindolol and chlorthalidone produced slight but significant improvement (p less than 0.05) with maximum MEFR (L/sec). Pulmonary function tests measured after isoprenaline were significantly worse in patients on propranolol compared to those on placebo, but were unchanged in patients on pindolol or chlorthalidone. The conclusions are: (1) Pindolol in antihypertensive doses does not produce airways obstruction and some improvement in pulmonary function may occur. (2) In comparable doses, pindolol has a positive effect on pulmonary function and propranolol a negative effect which, when summated, is statistically significant. (3) Propranolol, but not pindolol, appears to block the bronchodilator effects of isoprenaline. The lack of pulmonary function impairment may be due to intrinsic sympathomimetic activity properties of pindolol.

Chlorthalidone↗