Search PubMed⌕ Search

Biomedical subjects

K Ornstein

Publications and source records attributed to K Ornstein.

At least 19 recordsLinked to original sources
PubMed2001

Development of an adaptive multimedia program to collect patient health data.

BACKGROUND: Direct entry of personal health survey information into a computer by patients could streamline clinical data collection, improve completeness and accuracy of health information available to providers, and provide data for tailoring health education messages. Few computerized programs, however, have been developed to adapt the interface to diverse literacy levels, language, computer skills, and health literacy levels of the broad spectrum of patient populations. METHODS: To develop such a program, we conducted cognitive response interviews with a diverse sample of 21 adult participants from two North Carolina health clinics. Participants were placed into one of three interview categories: (1) low reading skill level, low computer skills; (2) high reading skill level, low computer skills; and (3) high reading skill level, high computer skills. The "think-aloud" technique was employed to elicit feedback on a series of computer interface screens and health risk assessment questions. RESULTS: Interface-related findings showed that preference for touchscreen versus keyboard data entry was not strongly related to computer skill level but was related to question type. Respondents with limited education indicated that they would not click on a "help" or hyperlink option to get more information and that frequent reminders of directions on the screen were needed. Content-related findings showed numerous misperceptions regarding meanings of common health questions and terminology (e.g., seat belt use and intravenous drugs). CONCLUSIONS: These findings have implications for health literacy and may have an impact on the accuracy of information obtained. Study results will be incorporated into the development and testing of an innovative, adaptive multimedia program.

Adult↗
PubMed2001

Mechanisms of action of beta-glucan in postprandial glucose metabolism in healthy men.

OBJECTIVE: To assess whether beta-glucan (which is fermented in the colon) lowers postprandial glucose concentrations through mechanisms distinct from a delayed carbohydrate absorption and inhibits de novo lipogenesis. DESIGN: Administration of frequent small meals each hour over 9 h allows a rate of intestinal absorption to be reached which is independent of a delayed absorption. A group of 10 healthy men received either an isoenergetic diet containing 8.9 g/day beta-glucan or without beta-glucan for 3 days. On the third day, the diet was administered as fractioned meals ingested every hour for 9 h. SETTING: Laboratory for human metabolic investigations. SUBJECTS: Ten healthy male volunteers. MAIN OUTCOME MEASURES: Plasma glucose and insulin concentrations, glucose kinetics, glucose oxidation, de novo lipogenesis. RESULTS: On the third day, plasma glucose and free fatty acid concentrations, carbohydrate and lipid oxidation, and energy expenditure were identical with beta-glucan and cellulose. Plasma insulin concentrations were, however, 26% lower with beta-glucan during the last 2 h of the 9 h meal ingestion. Glucose rate of appearance at steady state was 12% lower with beta-glucan. This corresponded to a 21% reduction in the systemic appearance rate of exogenous carbohydrate with beta-glucan, while endogenous glucose production was similar with both diets. De novo lipogenesis was similar with and without beta-glucan. CONCLUSION: Administration of frequent meals with or without beta-glucan results in similar carbohydrate and lipid metabolism. This suggests that the lowered postprandial glucose concentrations which are observed after ingestion of a single meal containing beta-glucan are essentially due to a delayed and somewhat reduced carbohydrate absorption from the gut and do not result from the effects of fermentation products in the colon.

Blood Glucose↗
PubMed2001

Characterization of Lyme borreliosis isolates from patients with erythema migrans and neuroborreliosis in southern Sweden.

Southern Sweden is an area of Lyme borreliosis (LB) endemicity, with an incidence of 69 cases per 100,000 inhabitants. The most frequent clinical manifestations are erythema migrans (77%) and neuroborreliosis (16%). There was no record of human Borrelia strains being isolated from patients in this region before the prospective study reported here. Borrelia spirochetes were isolated from skin and cerebrospinal fluid (CSF) from LB patients living in the region. A total of 39 strains were characterized by OspA serotype analysis, species-specific PCR, and signature nucleotide analysis of the 16S rRNA gene. Of 33 skin isolates, 31 (93.9%) were Borrelia afzelii strains and 2 (6.1%) were Borrelia garinii strains. Of six CSF isolates, five (83.3%) were B. garinii and one (16.7%) was B. afzelii. Neither Borrelia burgdorferi sensu stricto strains nor multiple infections were observed. The B. afzelii isolates were of OspA serotype 2. Three B. garinii strains were of OspA serotype 5, and the remaining four strains were of OspA serotype 6. All of the B. garinii strains belonged to the same 16S ribosomal DNA ribotype class. Our findings agree with earlier findings from other geographic regions in Europe where B. afzelii and B. garinii have been recovered predominantly from skin and CSF cultures, respectively. To further study the possible presence in Sweden of the genotype B. burgdorferi sensu stricto, which is known to be present in Europe and to occur predominantly in patients with Lyme arthritis, molecular detection of Borrelia-specific DNA in synovial samples from Lyme arthritis patients should be performed.

Antigens, Surface↗
PubMed1997

Preexercise feeding in untrained adolescent boys does not affect responses to endurance exercise or performance.

The effects of preexercise feeding on responses to endurance exercise and performance were investigated. Untrained adolescent boys (N = 13, age 14.9 +/- 0.5 years) completed three endurance test sessions separated by a minimum of 72 hr. Each session consisted of 75 min of cycling at 60% of VO2 max followed by a high-intensity performance test. Dietary conditions were a candy bar (C1: 280 kcal, 36 g CHO), fat-free fig bars (C2: 200 kcal, 44 g CHO), and a nonnutritive sweetened drink (C3: placebo), ingested 10 min prior to exercise. Respiratory gases, heart rate, blood glucose, and lactate concentrations were measured throughout the test. ANOVA results revealed significant time effects for all variables; however, no differences were seen among the conditions. Performance times, 311.9 +/- 38.5 s in C1, 316.2 +/- 37.3 s in C2, and 328.1 +/- 46.4 s in C3, were not significantly different among conditions. Thus, preexercise feeding did not affect responses to endurance exercise or performance in adolescent boys.

Adolescent↗
PubMed1995

An epidemiologic study of Lyme disease in southern Sweden.

BACKGROUND: Lyme disease is the most common vector-borne infection in some temperate regions of the Northern Hemisphere. However, for most areas of endemic disease reliable epidemiologic data are sparse. METHODS: Over a one-year period, we conducted a prospective, population-based survey of cases of Lyme disease in southern Sweden. The diagnosis was made on the basis of the presence of erythema migrans at least 5 cm in diameter or characteristic clinical manifestations such as arthritis, neuroborreliosis, and carditis. RESULTS: We identified 1471 patients with Lyme disease, for an overall annual incidence of 69 cases per 100,000 inhabitants. The incidence varied markedly according to geographic region, and there were several areas where disease was widely prevalent. The incidence varied according to age, with the highest rates among people 5 to 9 and 60 to 74 years of age, but not according to sex. The most frequent clinical manifestation was erythema migrans (seen in 77 percent of all cases), followed by neuroborreliosis (16 percent) and arthritis (7 percent). Carditis was rare. A preceding tick bite was reported by 79 percent of the patients. Bites in the head and neck region were more common among children than among adults and were associated with an increased risk of neuroborreliosis. CONCLUSIONS: Lyme disease is very common in southern Sweden, with a relatively high frequency of neurologic complications and arthritis. With the exception of the low incidence of carditis, the pattern of disease we found in Sweden was similar to that reported in the United States.

Adolescent↗
PubMed1987

Biochemical and radioautographic evidence for dopaminergic afferents of the locus coeruleus originating in the ventral tegmental area.

The dopamine (DA) content of the locus coeruleus (LC) and the uptake of tritiated DA in the presence of desmethylimipramine into fresh vibratome sections of the LC-area were determined in control rats and in rats whose ventral tegmental area (VTA) had been destroyed by local application of 6-hydroxydopamine (6-OHDA). Destruction of the VTA reduced the DA content and the number of dopaminergic fibers visualized by radioautography in the LC area. This indicates that the DA containing afferents of the LC originate, at least partly, in the VTA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1985

The morphogenesis of stereotyped behavior induced by the dopamine receptor agonist apomorphine in the laboratory rat.

The seemingly unrelated stereotyped locomotor "acts" reported in the literature to be produced by apomorphine in rats are shown to be composites, whose form and sequence are determined by the particular values of a few component variables which form a common denominator in each of the behaviors. Three variables, continuous snout contact, forward progression and turning, account for much of the behavior. In the course of the drug's action these emerge in succession and vary in amount, the latter two successively reaching a peak and subsiding. The interaction between forward progression and turning yields in sequence, forward walking, circling, revolving, tight pivoting and finally side-to-side movements of the forequarters around the relatively stationary hindquarters. Later behaviors in this list are gradually incorporated into the sequence as earlier ones are eliminated. The course of change in forward progression and turning is also reflected in changes in the sequence and in the direction of stepping of each of the four legs. The order in which the behavior unfolds under the drug is opposite to that manifested in ontogeny and in recovery from lateral hypothalamic damage, suggesting that at the particular high dose used, apomorphine is acting not only to activate the behavior but also to shut it down.

Animals↗
PubMed1984

Self-stimulation in the brain stem after ipsilateral precollicular decerebration.

Rats were tested for self-stimulation after unilateral removal of the entire forebrain anterior to the superior colliculus. The stimulating electrodes were situated in the peribrachial region, just lateral to the superior cerebellar peduncle. Of 27 animals tested, 8 still self-stimulated after ipsilateral decerebration. Self-stimulation was exhibited from as early as a few hours to as long as 119 days after decerebration. The results are discussed in the context of the search for neural elements that subserve reinforcing brain stimulation.

Animals↗
PubMed1982

Snout contact fixation, climbing and gnawing during apomorphine stereotypy in rats from two substrains.

Apomorphine, at doses greater than or equal to 10 mg/kg (intraperitoneally), produced two patterns of stereotypy. In rats from one supplier it induced predominantly gnawing while in those from another predominantly climbing, suggesting that the response to the drug is influenced by genetic and/or experimental factors. At lower doses, apomorphine induced climbing in both groups (ED50 = 1.4 mg/kg in each group) but oral behavior in only one of them (ED50 = 1.3 mg/kg in one, and 8 mg/kg in the second group). Thus, at a given dose of apomorphine, different patterns of stereotypy may result from an interaction between two phenomena: the relative setting of the thresholds to mouth and to climb, and an inverse relation between oral activity and climbing. Analysis of climbing suggests that this response is comprised of two (previously unidentified) fundamental effects of apomorphine: snout contact fixation and bodywise forward progression.

Animals↗
PubMed1981

Spreading depression induced by microinjection of enkephalins into the hippocampus and neocortex.

The opioid peptides Leu-enkephalin, Met-enkephalin and D-Ala2-Met-enkephalinamide were injected at various concentrations into the neocortex and hippocampus of rats to examine their effects on EEG activity and DC potentials. All three compounds were found to elicit spreading depression (SD) in both structures. Higher doses of Met-enkephalin were required to elicit SD as well as seizure activity. In the hippocampus the wave of SD was frequently preceded by seizure activity which was antagonized by naloxone pretreatment (40 mg/kg i.p.). Naloxone also prevented Leu-enkephalin-induced SD in the neocortex (but not in the hippocampus) and Met-enkephalin-induced SD in the hippocampus (but not in the neocortex). It failed to block SD elicited by D-Ala2-Met-enkephalinamide in both structures. Some of the various reported behavioral effects of intracranial injections of enkephalins could be artefacts of hippocampal and/or cortical spreading depression.

Animals↗
PubMed1981

Pinch-induced catalepsy in mice.

Pinch-induced catalepsy was readily obtained in five strains of mice following repeated administration of strong pinches at the scruff of the neck. This catalepsy outlasted the pinch by minutes and was more easily induced on retests 48 hr after the initial acquisition tests. Repetitive tail pinches and/or exposure to the testing procedure without pinches also resulted in immobility; however, this was weak in magnitude and short in duration. Treatments designed to prevent immobility between trials (swimming in water or housing in the home cage with normally behaving littermates) failed to block or modify pinch-induced catalepsy. Spacing the trials up to one pinch per 10 min did not affect the emergence of pinch-induced catalepsy, but at one pinch per 30 min it was abolished. Pinch-induced catalepsy is strikingly similar to the behavior elicited in mice when attacked by a cat. In both cases, immobility is produced by pinches or bites at the scruff of the neck, and it outlasts the duration of the stimulus. These results support the notion of pinch-induced catalepsy as an adaptive coping strategy, increasing the chance of survival in predator/prey confrontations.

Animals↗
PubMed1977

Interaction between morphine and reinforcing lateral hypothalamic stimulation.

The interaction between morphine and lateral hypothalamic self-stimulation in rats was investigated in three experiments. In nonaddicted animals injections of moderate doses of morphine (8 mg/kg) resulted in a short-lasting increase in the self-stimulation threshold. Injections of low doses (2 mg/kg) did not alter the self-stimulation threshold significantly. In addicted animals self-stimulation thresholds were significantly lower 2 h compared to 22 h after injection of 200 mg/kg morphine hydrochloride (calculated as the salt). A 16 mg/kg injection of morphine in non-addicted rats suppressed self-stimulation. However, when the animals were administered noncontingent priming stimulation and were hand-shaped toward the lever whenever they left it, they continued to lever-press throughout the entire 90-min postinjection testing period. The animals that were neither primed nor shaped (and therefore remained unstimulated), however, showed a significantly better recovery when tested 90 min after the injection; i.e., their response rate was higher than that of the primed and shaped animals, which were engaged in bar-pressing throughout the entire testing procedure.

Animals↗