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Biomedical subjects

M Horvat

Publications and source records attributed to M Horvat.

At least 19 recordsLinked to original sources
PubMed1998

The relative cost of children's physical play.

There has been a long-standing debate regarding the functions of play during childhood. An important, but neglected, first step in this debate entails documenting the costs associated with play. In this study we analysed energetic costs (expressed in terms of caloric expenditure) associated with physical play in four field experiments of play in primary school children. Experiment 1 established the concurrent validity of an observational check list to estimate caloric expenditure of children's physical play. Experiment 2 compared caloric expenditure of the play (defined as all behaviour exhibited during play time) for two age groups of children during playtime outdoors and during indoor sedentary activity; caloric expenditure of outdoor activity was greater and was significantly correlated with ambient temperature. In experiment 3, children were observed during indoor play to control for the influence of ambient temperature. Outdoor physical play was more energetically costly than indoor physical play. In experiment 4, children's behaviour was observed outdoors and caloric expenditure for play, games and other activities was compared. Physical play was more costly than other forms of behaviour and games. Estimates of total energetic costs of play ranged from 6 to 15%. Results are discussed in terms of the relatively low caloric costs of play. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Profound circulatory shock following heroin overdose.

A 17-year-old previously healthy girl with profound circulatory shock following a heroin overdose is reported. Except for opiates no other substances and specifically no cocaine were found in the blood and urine samples. Even though the mechanism of shock is not completely understood, severe depression of left ventricular contractility seems to be the predominant reason. Acute right heart failure with decreased pulmonary capillary wedge pressure and arterial vasodilatation resulting in maldistribution of cardiac output cannot be ruled out as possible contributing factors. The shock was successfully reversed with volume loading and a high dose of dobutamine. The recovery was uneventful and the patient was discharged with normal cardiac function.

Adolescent↗
PubMed1998

Treatment of out-of-hospital cardiac arrest in Ljubljana: outcome report according to the 'Utstein' style.

We investigated survival of patients with out-of-hospital cardiac arrest in Ljubljana according to the 'Utstein' style. Ljubljana consists of urban, suburban and semi-rural communities which encompass an area of 1615 km2 with 397306 residents. The area is served by a single response emergency medical system and local family practitioners. Between January 1, 1995 and December 31, 1997 cardiac arrest was confirmed in 966 patients. Cardiopulmonary resuscitation was attempted in 454 patients (47%). Collapse of presumed cardiac etiology (337 patients) was either bystander-witnessed (89%), un-witnessed (9%) or EMS personnel-witnessed (2%). Asystole was documented in 55%, ventricular fibrillation or tachycardia in 36% and other non-perfusing rhythms in 9% of these patients. Lay-bystander basic life support was performed in 19%. Nineteen patients (5.6%) survived to hospital discharge and 12 of them were independent in daily life. The survival of subgroups with bystanders-witnessed collapse and bystanders-witnessed ventricular fibrillation was 6.4 and 13%, respectively. Collapse of non-cardiac etiology (117 patients) was preceded by either respiratory failure (41), politrauma (22), circulatory shock (19), cerebrovascular incident (ten), intoxication (nine), strangulation (seven), electrocution (five) or drowning (four patients). Only five patients (4.2%) survived to hospital discharge. Hospital treatment of patients after successful initial cardiopulmonary resuscitation was associated with high mortality and required considerable resources.

Activities of Daily Living↗
PubMed1998

Positive biochemical effects of a bioartificial liver support system (BALSS) in a porcine fulminant hepatic failure (FHF) model.

This study describes biochemical changes in the plasma and blood of pigs with devascularised livers treated in a bioartificial liver support system (BALSS). Porcine hepatic cells were incubated with collagen-coated dextran microspheres (CDM) for 3 hours and the medium tested to determine cellular metabolic activity. Incubation continued for a further 18 hours during which the hepatic cells attach to the CDM. The CDM-attached cells were inoculated into a hollow fibre bioreactor which was part of an extracorporeal support system. Hepatic cell content of the bioreactor was 6 x 10(9) cells. The system was tested in a controlled trial in pigs prepared in a surgical model of fulminant hepatic failure (FHF). When plasma from FHF pigs was circulated through the device containing hepatic cells, there was significantly less increase in the accumulation of ammonia and most amino acids, together with a decrease in plasma lactate and of one amino acid, compared to control experiments when hepatic cells were excluded. We conclude that primary porcine hepatocytes can contribute beneficial metabolic function in a BALSS.

Adenosine Triphosphate↗
PubMed1997

Influence of hemodynamic changes on neuroendocrine response in acute heart failure.

We studied 15 patients with acute deterioration of chronic left ventricular heart failure. We compared the influence of reduction of ventricular filling pressures with glyceryl trinitrate versus reduction of ventricular filling pressures with diuretics on plasma concentration of epinephrine, norepinephrine, aldosterone and renin activity. Reduction of ventricular filling pressures with glyceryl trinitrate had no influence on plasma concentrations of epinephrine, norepinephrine, aldosterone and renin activity. After reduction of ventricular filling pressures with diuretics plasma concentrations of epinephrine, norepinephrine and aldosterone decreased, while plasma renin activity did not change. We conclude that there is a difference in the influence of reduction of ventricular filling pressures with glyceryl trinitrate versus reduction of ventricular filling pressures with diuretics, on neuroendocrine response in patients with acute deterioration of left ventricular heart failure. Thus some of the neuroendocrine effects of glyceryl trinitrate are likely to be different from those of diuretics, though that they both produce a reduction in left ventricular filling pressure.

Acute Disease↗
PubMed1997

Heart conduction disturbances and cardiovascular collapse after disopyramide and low-dose metoprolol in a patient with hypertrophic obstructive cardiomyopathy.

Disopyramide as an antiarrhythmic can be prescribed to patients with atrial fibrillation and, owing to its negative inotropic effect, to patients with hypertrophic obstructive cardiomyopathy. It is known that in patients with cardiac conduction disturbances and heart failure, disopyramide can adversely affect heart rhythm and conduction and induce cardiovascular collapse. A patient with hypertrophic obstructive cardiomyopathy and paroxysms of atrial fibrillation is described who was treated with disopyramide and also, during the 5 days before admission, with metoprolol. In spite of normal cardiac conduction and function before disopyramide, this treatment was followed by hypotension, bradycardia, and cardiac conduction disturbances. Our case shows the potential for disopyramide, especially when combined with metoprolol, to induce grave adverse effects even in patients with normal cardiac conduction and ventricular function.

Anti-Arrhythmia Agents↗
PubMed1997

Isokinetic torque, average power, and flexion/extension ratios in nondisabled adults and adults with mental retardation.

For successful placement of individuals with mental retardation into community environments, a minimal amount of functional strength is required to promote self-independence. Since muscular strength and power are commonly deficient in these groups, the purpose of this study was to compare isokinetic elbow flexion and extension peak torque (Nm), average power (W), and corresponding flexion/extension ratios of adults males with Down syndrome, with mental retardation without Down syndrome, and sedentary adult males without mental retardation. Subjects with Down syndrome (N = 9), mental retardation without Down syndrome (N = 13), and without mental retardation (N = 13) were tested for elbow flexion and extension peak torque and average power at 60 and 90 degrees/sec on a Cybex 340 isokinetic dynamometer. Results indicated: 1) subjects without mental retardation displayed significantly greater ( p < 0.01) peak torque and average power elbow flexion and extension than subjects with Down syndrome and subjects with mental retardation without Down syndrome at speeds of 60 and 90 degrees/sec, and 2) there were no significant differences between groups in peak torque and average power elbow flexion/extension ratios at both angular velocities. The results of the data analysis support the premise that adults with mental retardation are in need of exercise programs to improve muscular strength.

Adult↗
PubMed1996

Peak torque, average power, and hamstrings/quadriceps ratios in nondisabled adults and adults with mental retardation.

OBJECTIVE: To compare isokinetic hamstring and quadriceps peak torque (Nm), average power (watts), and corresponding hamstring/quadriceps (HQ) ratios (as percentages) of adult men with Down syndrome(DS), with mental retardation without Down syndrome (NDS), and nondisabled sedentary controls (SC). DESIGN: Repeated measures analysis of variance. SETTING: Subjects were tested at a university exercise science laboratory. SUBJECTS: Volunteer sample of 35 subjects: SC(n=13), DS(n=9), and NDS (n=13). INTERVENTION: Subjects performed isokinetic strength tests at 60 degrees /sec and 90 degrees/sec using gravity effected torque procedures. Subjects with DS and NDS performed the test on two separate days with best results selected for statistical comparisons. Sedentary controls performed the test once. MAIN OUTCOME MEASURES: Isokinetic hamstring and quadriceps peak torque and average power, and corresponding HQ ratios on a Cybex 340 isokinetic dynamometer. RESULTS: In all isokinetic parameters measured, sedentary controls demonstrated significantly higher scores than subjects with DS and NDS. There was no significant difference between subjects with DS and NDS, although mean peak torque and average power scores were greater in subjects with NDS. Finally, there were no significant differences in peak torque and average power HQ ratios across groups (p> .01), although group mean peak torque HQ ratios were greatest for sedentary controls (range=61% to 63%) and approximated accepted HQ ratio norms, and lowest for subjects with DS(range=40% to 46%). CONCLUSIONS: Individuals with mental retardation are in need of progressive resistance exercise programs to improve hamstring and quadriceps strength and normalize HQ strength and power ratios.

Adult↗
PubMed1996

Preclinical trial of a bioartificial liver support system in a porcine fulminant hepatic failure model.

BACKGROUND: This study describes the pre-clinical trials of an extracorporeal bioartificial liver support system (BALSS). It includes the biochemical changes which occur in the plasma and blood of pigs with devascularized livers when the plasma is treated in a BALSS, and the testing of the system for presence or absence of infective agents, pyrogens and for toxicity. METHODS: Hepatic cells were prepared from littermate juvenile white landrace pigs with a double-step collagenase digest technique. The cell preparations were incubated with collagen-coated dextran microspheres (CDM) for 3 h and the medium was tested to determine cellular metabolic activity. Incubation continued for a further 20 h during which the hepatic cells attach to the CDM. The CDM-attached cells were inoculated into a hollow fibre bioreactor which was part of an extracorporeal liver support system. RESULTS: Hepatic cell content of the bioreactor was 6 x 10(9) +/- 3 x 10(8) cells, equivalent to those present in half a pig's liver. The system was tested in a controlled trial with the plasma of pigs with fulminant hepatic failure (FHF) due to devascularized livers. When plasma from FHF pigs was circulated through the device there was significantly less of an increase in the accumulation of ammonia, lactate and most amino acids when hepatic cells were included in the circuit compared with those in control experiments when they were excluded. Similar changes occurred in procine blood. There were few infections diagnosed and an absence of pyrogens, endotoxins and toxicity in the bioreactor contents or in the terminating reservoir or animal blood samples. CONCLUSIONS: We believe that the results, demonstrating function of the porcine hepatic cells in the circuit, together with low risks, justify a clinical trial of use of the BALSS in Australia.

Amino Acids↗
PubMed1996

Subacute rupture of the left ventricular free wall after acute myocardial infarction. Three cases of long-term survival without emergency surgical repair.

Rupture of the left ventricular free wall after acute myocardial infarction (AMI) has been regarded as uniformly fatal unless emergency surgical repair is performed. Among 2,862 patients admitted with AMI to our ICU during the last 8 years, 107 patients developed rupture of the left ventricular free wall. Twenty-nine patients had a subacute course and three of them survived for prolonged periods without having to have emergency surgical repair. At the onset of rupture on day 1 through 7 after AMI, the three survivors developed sudden hypotension accompanied by a new pericardial effusion. They were initially managed with hemodynamic support. Two patients had elective open-heart surgery 2 to 3 months after AMI, whereas one patient did nt require surgery. All three survived 1 1/2 to 8 1/2 years after AMI. This report indicates that a small subset of patients with subacute ventricular free wall rupture has a benign course that may allow for prolonged survival without having to have emergency surgical repair.

Aged↗
PubMed1996

Augmented feedback for enhanced skill acquisition in individuals with traumatic brain injury.

Coincident timing by individuals who exhibit traumatic brain injury was measured under conditions of no knowledge of results (no KR; n = 12), KR on every trial (n = 14), summary KR (n = 13), and average KR (n = 12). Following acquisition trials, groups performed immediate and longer retention trials without KR. Absolute constant error and variable error, analyzed in separate repeated-measures analyses of variance, indicated that during acquisition trials subjects receiving KR on every trial were the most accurate and the most consistent in their responses; however, subjects in groups receiving summary and average KR were the most accurate during immediate retention, with the group receiving summary KR being the most accurate during longer retention.

Adolescent↗
PubMed1995

Dietary mercury intake and human exposure in an Adriatic population.

A study was conducted to examine human exposure to mercury through dietary mercury intake in a population living in an industrially non-polluted area of the Adriatic Sea. The results have shown that approximately 20% of the subjects had a weekly dietary mercury intake above the provisional tolerable weekly intake (PTWI), primarily those consuming fish and other seafood > 6 times/week. The estimated seafood consumption corresponding to a mean intake of PTWI of 300 micrograms total mercury was 1559 g, and 1365 g for a PTWI of 200 micrograms methylmercury. However, the total mercury content in hair in individuals consuming total mercury above the PTWI was in the range of 1.3-12.9 micrograms/g, whereas the methylmercury content in hair in subjects consuming methylmercury above the PTWI was between 1.1-10.8 micrograms. Thus, the mercury content in hair did not reach the critical level at which toxic effects of mercury could be expected. The results, particularly those related to methylmercury exposure, did not differ significantly from data reported earlier from an industrially polluted area, thus indicating that the mercury content of fish and consequent human exposure to mercury reflects primarily the general ecological characteristics of the Adriatic, rather than the impact upon a specific local pollution.

Adolescent↗
PubMed1995

Coincident timing by nondisabled, mentally retarded, and traumatic brain-injured individuals under varying target-exposure conditions.

Coincident timing by 15 nondisabled individuals, 15 mentally retarded and 15 traumatically brain injured was measured under varying target-exposure conditions. Absolute constant error, constant error, and variable error were analyzed in separate repeated-measures analyses of variance for early performance (first block of practice), late performance (last block of practice), and retention (last block of retention). Subjects with mental retardation displayed the least accurate and most variable coincident-timing responses. Nondisabled subjects were most influenced by target-exposure time; subjects with traumatic brain injury were most influenced by target-viewing distance; and subjects with mental retardation were most influenced by a combination of target velocity and target-viewing distance. Subjects with mental retardation displayed a too-early response bias, while nondisabled subjects tended to have a too-late response bias. Individuals with traumatic brain injury had a variable response bias.

Acceleration↗
PubMed1994

No indication of in vivo methylation of inorganic mercury in chloralkali workers.

It has been shown in vitro that human oral and intestinal bacteria are able to methylate inorganic mercury (Hg) to methylmercury (MeHg). In vivo methylation has been reported for guinea pigs, and several studies have found higher levels of organic Hg in blood of workers exposed to inorganic Hg. In search for indications of in vivo methylation of Hg, we determined total Hg in urine (U), plasma (P), and erythrocytes (Ery), and MeHg in erythrocytes, in 22 chloralkali workers exposed to inorganic Hg, and in 22 age-matched referents. The subjects in both groups ate fish not more than once a week. MeHg was determined using ion exchange separation and cold vapor atomic absorption spectrometry. The mean concentrations of total mercury in chloralkali workers and referents were 26 vs 2.3 micrograms/g creatinine (U-Hg), 9.7 vs 1.8 ng/g (P-Hg), and 11.4 vs 5.6 ng/g (Ery-Hg). The mean Ery-MeHg concentrations were 3.0 vs 3.7 ng/g, and there were no correlations between Ery-MeHg on the one hand and U-Hg or P-Hg on the other. Our results indicate no significant in vivo methylation of inorganic Hg in man. Contradictory results from previous studies may be due either to bias owing to fish consumption or to analytical shortcomings.

Alkalies↗