PubMed Health⌕ Search

Biomedical subjects

D Hunt

Publications and source records attributed to D Hunt.

At least 19 recordsLinked to original sources
PubMed1992

Clinical experience with surgery for paroxysmal supraventricular tachycardia: a report of 103 cases.

One-hundred-and-three patients underwent surgery for paroxysmal supraventricular tachycardia (PSVT). In eighty-three patients (81%), PSVT was due to an accessory atrioventricular pathway (Group I) and in 20 (19%) to Atrioventricular Junctional (AV nodal) Reentrant Tachycardia (AVJRT:Group II). Initial surgery successfully divided 77 of 83 accessory pathways, including 58 of 60 left free wall pathways, 12 of 15 posteroseptal pathways, six of seven right free wall pathways and one anteroseptal pathway. Twenty patients had successful surgery for AVJRT. Surgery was performed with low morbidity and no early or late mortality in either group. One patient in each group required permanent pacemaker implantation. Immediate (within one week) postoperative electrophysiological study using epicardial wires was performed in 96% of patients and repeat electrophysiological study six months later was possible in 65/103 (63%) patients. Patients with surgery for accessory pathways were followed-up for a mean 34 +/- 23 months, while those with surgery for AVJRT for a mean of 13 +/- seven months. No patient with successful surgery has had a clinical recurrence of PSVT. Thus the results indicate that surgery is a safe and curative therapy for patients with PSVT.

Adolescent↗
PubMed1992

Immediate and long-term results of percutaneous balloon aortic valvuloplasty: a report of 33 procedures.

The purpose of this study was to evaluate the immediate and long-term clinical and haemodynamic effects of Percutaneous Balloon Aortic Valvuloplasty (PBAV). Thirty-three procedures were performed in 27 patients, 11 males and 16 females with a mean age of 72 years. The peak to peak systolic gradient across the aortic valve decreased by 52%, from 67 +/- 24 mmHg to 31 +/- 15 mmHg (p < 0.0001) and the aortic valve area increased by 35%, from 0.48 +/- 0.16 to 0.67 +/- 0.21 cm2 (p < 0.001) after PBAV. There were no procedural deaths. Minor complications occurred in seven patients. Eighty-one per cent of patients (27 procedures) showed immediate symptomatic improvement, five remained symptomatic and one died in hospital before discharge. In a mean follow-up of 17 +/- 12 months (range six to 38 months), eight patients died due to congestive cardiac failure, six underwent repeat PBAV, three died due to noncardiac causes and three had recurrent symptoms controlled on medical therapy. Event free survival at 15 months was 43%. In conclusion PBAV produces a satisfactory immediate clinical and haemodynamic result, however, considering the high rate of symptom recurrence, this procedure has a beneficial role only in short-term palliation of severely symptomatic patients who are unable to undergo aortic valve replacement.

Actuarial Analysis↗
PubMed1992

Coronary-pulmonary artery fistula arising distal to obstructive coronary lesions.

We report 2 cases of coronary-pulmonary artery fistulae (CPF) arising distal to obstructive coronary artery disease. The fistula in the first patient was in the form of a tortuous dilatation of the distal portion of the right coronary artery and opened into the right pulmonary artery. In the second case, the fistula, a plexus of vessels, arose from the left anterior descending artery and entered the left pulmonary artery. Both the fistulae were successfully ligated at the time of concurrent coronary artery bypass graft surgery.

Aged↗
PubMed1992

Single coronary artery: a report of 2 cases.

An isolated single coronary artery is a rare congenital anomaly. We report 2 patients each of whom had a single coronary artery with an obstructive atherosclerotic lesion in one of its branches. In the first patient angioplasty was successfully performed using a perfusion catheter whilst in the second, the procedure was considered inappropriate as the patient had chronic total occlusion.

Angioplasty, Balloon, Coronary↗
PubMed1991

Heparin-binding serum protein(s) is required for the protection of sialyltransferase released during the incubation of rat jejunal slices.

Incubation of rat jejunal slices in Krebs-Ringer bicarbonate buffer (KRB) required the presence of heat-inactivated horse serum (HHS) in order to show time-dependent release of sialyltransferase into the medium. Sialyltransferase activity could not be detected in the medium when KRB alone or KRB supplemented with either albumin or glycerol was used in the incubations. The viability of the jejunal slices for up to 4 h of incubation was determined by studying the incorporation of glucosamine and leucine into acid-insoluble proteins. Supplementation of KRB with HHS had no beneficial effect on the rate of incorporation of leucine and glucosamine into proteins. KRB medium obtained after different periods of incubation contained higher trypsin-like activity than KRB medium containing HHS. Various antiproteases present as supplements to KRB resulted in the release of sialyltransferase activity from the jejunal slices. Among these antiproteases, alpha 1-proteinase inhibitor (alpha 1-PI) was the most effective. Also, HHS added to KRB immediately following incubation resulted in partial restoration of sialyltransferase activity in the medium, suggesting the presence of anti-proteolytic factors in HHS. The addition of increasing concentrations of heparin to incubations containing HHS caused a decrease in the medium sialyltransferase activity. The heparin-binding fraction (HBF) from HHS, when added to incubations, was able to protect the sialyltransferase released into medium. However, HHS depleted of its heparin-binding fraction by heparin-agarose affinity chromatography was unable to protect the sialyltransferase. HBF was separated into high- and low-molecular-mass fractions (fractions A and B respectively) by gel-filtration chromatography. The capacity to protect the released sialyltransferase was contained in fraction B. Fraction A contained multiple bands on SDS/PAGE and did not protect the enzyme. Fraction B contained a major protein band on the gel which corresponded to the migration of a similar band in human alpha 1-PI. HBF as well as fraction B isolated from HHS showed anti-trypsin-like activity. The results presented indicate that HHS contains a heparin-binding protein(s) similar to human alpha 1-PI which plays a role in the protection of sialyltransferase released from jejunal slices.

Animals↗
PubMed1991

Ventricular dysfunction following direct-current shock atrioventricular junction ablation.

Catheter-induced His bundle ablation for refractory supraventricular arrhythmias is most commonly performed with direct-current shock energy of 200-300 joules. The high energy pulse delivered by direct-current shock produces a lesion in the atrioventricular node by fulguration, with the residual energy being dissipated as a pressure wave. The effect of direct-current shock His bundle ablation on global and regional ventricular function was assessed in 14 consecutive patients by radionuclide ventriculography performed before and after ablation and again three months later. All studies were performed with ventricular pacing at 110 bpm. Global left ventricular ejection fraction was found to be significantly reduced at the three month study (0.43 +/- 0.03 vs 0.50 +/- 0.03, pre ablation, p = 0.02). A significant reduction in wall-motion score was also seen in six of the seven patients who had normal wall motion in pacing rhythm prior to ablation. Deterioration was mainly seen at the left and right ventricular apices. The observed reduction in ventricular function that follows direct-current shock His bundle ablation may result from myocardial damage from electro-coagulation or from barotrauma and supports continued investigation into alternative, less traumatic energy sources for the procedure.

Adult↗
PubMed1991

Stealing and dealing: cocaine and property crimes.

A common thread in all studies of this nature is the level of use of cocaine and/or the concomitant use of other drugs, suggesting that economic necessity plays a role in the decision to commit crimes to help defray the costs of use. While a truly causal link between use and crime activity in marginal income populations is apparent. Whether that association is driven primarily by economics or lifestyle considerations is not answered by simple examination of the numbers. Statistically, the use of cocaine is related to criminal activity as a function of the income level and prior criminal experience of the user. This relationship is better defined by looking at the threshold effect in marginal income groups, where use that goes beyond what the pocket can bear produces a significantly greater chance that illegal sources will be found. However, many occasional users or even regular users with resources are able to fund their use through routine sources and never resort to criminal activity or to unconventional financial resources. A large number of cocaine users probably fall into this middle ground: they are neither the "high rollers" that often make the media nor the traditional heroin/cocaine addicts. For them, criminal activity may surface when use exceeds funds or not at all. For still others, cocaine is part of a criminal lifestyle rather than a motivation for it. Statistically, all these cocaine users look the same, though the relationship between their use and their crime may be quite varied. The descriptions of three cases discussed in an earlier paper (Hunt et al. 1985) clarify this point. The first case was a 32-year-old white male former heroin addict and former drug dealer who reported cocaine use intravenously three to four times a month, smoked marijuana weekly, and used no other drugs. He was married, working, and had a small child. He also reported dealing in stolen merchandise and clothing that he got from someone else to sell. This pattern had been his custom for several years, observed at close hand by the author, and he had not been arrested for many years, though he had a prior history of arrests dating back more than 15 years. This individual did not link his selling stolen merchandise with his cocaine use. He linked it with the need for supplementary funds and was as likely to deal goods for Christmas money as for cocaine.(ABSTRACT TRUNCATED AT 400 WORDS)

Cocaine↗
PubMed1990

Coronary angioplasty for chronic total occlusion reduces the need for subsequent coronary bypass surgery.

Coronary angioplasty was performed in 44 consecutive patients with total occlusion that lasted longer than 1 week. The primary success rate was 59%. Angiographic restudy in 25 of the 26 successful patients (96%) revealed restenosis in 17 patients (65%), which was asymptomatic in seven (44%). Significant correlates of restenosis were mean luminal stenosis at the conclusion of the procedure and symptom recurrence. Clinical follow-up at a mean of 31 +/- 12 months revealed that coronary artery bypass surgery was more frequent in patients who had an unsuccessful initial angioplasty procedure (7/18 vs 3/26; p = 0.04). Nine patients (35%) who had an initially successful procedure required a second angioplasty for symptomatic restenosis. Angioplasty for totally occluded coronary arteries has a high incidence of restenosis that is often asymptomatic. This procedure can, however, lead to a reduction in the need for coronary artery bypass surgery for symptom control.

Angiography↗
PubMed1990

Electrical ablation of posteroseptal accessory pathways.

Electrical ablation of a posteroseptal accessory pathway by delivery of direct current electrical energy at the coronary sinus ostium was attempted in six patients. As a result of 12 procedures in these six patients, the posteroseptal accessory pathway was successfully ablated in one patient. Retrograde conduction only was affected in a further three patients, abolishing paroxysmal supraventricular tachycardia in two and reducing the tachycardia rate in one. One of the six patients developed coronary sinus perforation requiring prompt pericardial aspiration. The procedure is complicated, time consuming, of limited efficacy and coronary sinus perforation is a significant risk. Surgery remains the preferred option as a curative procedure for arrhythmias due to posteroseptal accessory pathway.

Adult↗
PubMed1990

"Pacecare"--a computerized database for pacemaker follow-up.

A computerized database for pacemaker follow-up has been designed to run on IBM compatible hardware and to accept pulse generator and lead models of all manufacturers. Stored data includes patient, physician and implant details, indications for pacing, underlying rhythm, complications and management, program settings, and follow-up measurements. Typing is minimized by the use of "pop-up" lists and prepared pulse generator template displays. At each follow-up visit a patient's file is retrieved by surname or number, a visit record created, and measurements documented. As the template of the previous visit is used, recording of the clinic visit takes less than 1 minute. Changes in pacing rates (base or magnet), pulse widths, lead thresholds, lead impedance, and battery cell impedance can be displayed graphically for immediate recognition of end-of-life parameters or suspected malfunction. The program will print patient, implantation and clinic visit summary reports, clinic appointment lists, letters to patients, and annual reports. Two Melbourne hospitals have now entered over 3,600 patients into the database. Valuable information has been obtained regarding implantation details and trends with pulse generator and lead usage. Pacecare is a sophisticated, yet user friendly, computerized database for pacemaker follow-up. Recording of clinic visits is fast and changes in testing parameters can be recognized immediately.

Computer Systems↗
PubMed1990

Regulation of sialyltransferase activity in intestinal segments of rats.

A differential distribution of sialyltransferase (ST) in different regions of intestine has been shown. Jejunum and ileum homogenates from rats showed almost exclusive presence of alpha-2-3 ST (to Gal in Gal beta-1-4GlcNAc and/or to Gal in Gal beta-1-3GalNAc). In contrast, colon homogenates showed the presence of both alpha-2-3 ST (as above) and alpha-2-6 ST. Incubation of intestinal slices in presence of heat-inactivated horse serum (HHS) showed a time- and temperature-dependent secretion of soluble ST into the medium. Both jejunum and ileum slices showed high rates of secretion of alpha-2-3 ST. Colon slices, though rich in alpha-2-6 ST, secreted only alpha-2-3 ST. Colchicine, an anti-mitotic drug, injected into rats caused about 10-fold increase of the serum ST level. Jejunum slices from colchicine-treated rats showed an increased secretion of alpha-2-6 ST, suggesting that intestine undergoes a change in the expression of normal secretion of alpha-2-3 ST to a secretion of alpha-2-6 ST. The secretion of ST from incubated intestinal slices was inhibited by heparin. Certain protein factors (anti-proteases) in HHS bind to heparin-sepharose column and these protein factors are responsible for causing the secretion of ST into the medium. It has also been found that a supernatant fraction of the colon homogenate activated ST. Gel chromatography on HPLC produced 3-4 protein fractions from the colon cytosol and one of this fraction bearing high molecular weight proteins produced the maximum activation of ST.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Improved prognosis since 1969 of myocardial infarction treated in a coronary care unit: lack of relation with changes in severity.

OBJECTIVE: To study changes from 1969 to 1983 in the prognosis of patients with acute myocardial infarction treated in a coronary care unit. DESIGN: Mortality follow up of all patients with definite acute myocardial infarction. SETTING: The coronary care unit of the Royal Melbourne Hospital, a tertiary referral centre. SUBJECTS: 4253 Patients (3366 men, 887 women) admitted from 1969 to 1983. MAIN OUTCOME MEASURE: Mortality recorded at discharge from hospital and 12 months after admission. RESULTS: Details of clinical findings, history, electrocardiograms, arrhythmias, and radiological findings were recorded on admission. Mean ages were 63 for women and 57 for men, and women had haemodynamically more severe infarcts than men. In the later years patients were older and had less severe infarcts. Overall, hospital mortality in men was 16.7% in 1969-73 and 8.5% in 1979-83 and declined in all grades of the Norris and Killip infarct severity indices compared with a constant 19.2% in women. Even after adjustment for age and severity by logistic regression, hospital mortality fell in men by an average of 8% (95% confidence interval 4% to 11%) a year but remained constant in women. By 1983 male mortality was 60% that of women of similar age and comparable severity of infarction. Mortality of hospital survivors at 12 months declined by 7% (4% to 9%) a year in both sexes, even after adjustment for age and severity, with a male to female mortality ratio of about 0.8. New indices were derived to predict mortality in hospital and at 12 months. CONCLUSION: The observed declines in mortality cannot be explained by changes in severity of infarction or in prognostic characteristics of patients.

Adult↗
PubMed1989

Determinants of restenosis and lack of effect of dietary supplementation with eicosapentaenoic acid on the incidence of coronary artery restenosis after angioplasty.

The effect of an eicosapentaenoic acid-rich encapsulated preparation of fish oil on the incidence of early restenosis after coronary angioplasty was assessed by a randomized double-blind placebo-controlled study. A total of 108 patients received either 10 capsules of fish oil (1.8 g eicosapentaenoic acid, 1.2 g docosahexaenoic acid) or 10 control capsules (50% olive oil, 50% corn oil), commencing the day before angioplasty and continuing for 4 months after angioplasty, in addition to treatment with aspirin and verapamil. In 101 (94%) of the 108 patients, follow-up angiographic or postmortem result was evaluated at a mean (+/- SD) of 100 (+/- 22) days. Angiographic restenosis was observed in 34% of patients (29% of lesions) in the fish oil-treated group and 33% of patients (31% of lesions) in the control group (no significant difference). The overall incidence of angiographic restenosis was significantly higher in patients with 1) recurrent angina pectoris, 2) a positive exercise test at follow-up after angioplasty, 3) residual stenosis greater than 30% immediately after angioplasty, and 4) dilation of the left anterior descending or right coronary artery. Biochemical investigations showed a greater decrease in the serum triglyceride levels in the fish oil-treated group versus the control group (p less than 0.05) but no differences between the two groups in cholesterol levels or platelet counts over the 4 month period. In conclusion, in this study, the administration of fish oil at a dose of 10 capsules/day did not reduce the incidence of early restenosis after coronary angioplasty.

Adult↗
PubMed1989

Blood pressure changes with age in two ethnic groups in Fiji.

Blood pressure was studied in urban and rural samples of the Melanesian and Indian populations of Fiji during a National Cardiovascular Disease and Diabetes Survey in 1980. Mean blood pressures rose with age and tended to be higher in urban than in rural populations, particularly in the middle age range. There was no clear or significant difference between the ethnic groups. When the prevalence of hypertension was studied (using WHO criteria) similar age, geographic and ethnic differences were found. Comparisons with data from 1960 revealed no significant change in mean blood pressures during the 20-year interval. Rural populations were leaner and appeared to consume less salt than did urban groups. There were positive and significant correlations between blood pressure and triceps skinfold thickness in most subgroups.

Age Factors↗
PubMed1989

Early and late results of balloon valvuloplasty for severe aortic stenosis.

Balloon aortic valvuloplasty has been used as treatment for selected patients with severe aortic stenosis. We report our experience of 11 procedures, performed on ten patients between October 1987 and June 1988. The peak aortic systolic gradient was reduced by 53% from 77 +/- 22 to 37 +/- 14 mmHg (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 (p less than 0.0001) whilst cardiac output did not change significantly (4.1 +/- 1.7 to 3.8 +/- 1.6 L/min). Aortic valve area was increased by 50%, from 0.4 +/- 0.2 to 0.6 +/- 0.2 cm2 (p less than 0.0001). Initial symptomatic improvement was achieved in eight patients. Echocardiographically demonstrated aortic regurgitation did not increase after valvuloplasty. There were no deaths during the procedure, no embolic events and no femoral artery complications. The mean follow-up for survivors was 9 +/- 3 months. Five patients died and three had symptom recurrence at an average of 13 weeks (six-24 weeks). Only two patients reported a continued improvement in symptoms. Balloon aortic valvuloplasty produced a small increase in aortic valve area and a satisfactory initial clinical response, but there was a high incidence of symptom recurrence. The procedure may have a role in the short-term palliation of severely symptomatic patients who are unable to have aortic valve replacement.

Acute Disease↗
PubMed1989

Social-psychological environments and cognitive achievement.

Differences in social-psychological environments between parochial and public schools, and between mathematics and English courses, were investigated for 317 boys and girls in Grade 10. Multivariate and univariate analyses of variance produced significant main effects and an interaction of school x subject. Differential validities of environmental variables in predicting achievement using multiple regression suggested that perception of the learning environment for course content substantially predicted achievement in that course content. Incremental validity of the learning environment with achievement when IQ was partialled out was also substantial. Implications for instructional effectiveness and school organization are discussed.

Achievement↗