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Biomedical subjects

S J Goldberg

Publications and source records attributed to S J Goldberg.

At least 19 recordsLinked to original sources
PubMed1995

Contractile properties of the tongue muscles: effects of hypoglossal nerve and extracellular motoneuron stimulation in rat.

1. Stimulation of the whole hypoglossal (XIIth) nerve or its medial or lateral branch in the rat produced two major movements of the tongue as measured with a single force transducer attached to the tip of the tongue. Stimulation of the whole XIIth nerve or the lateral branch produced a retrusion of the tongue, whereas stimulation of the medial branch produced a protrusion. 2. The average retrusive twitch tension evoked by stimulation of the XIIth nerve (11.25 g) or the lateral branch (12.02 g) was significantly greater (P < or = 0.0001) than the protrusive twitch tension (1.05 g) elicited by medial branch stimulation. The tetanic tension produced by lateral branch stimulation (36.82 g) was significantly greater (P < or = 0.007) than the whole nerve tetanic tension (28.23 g). The greater tension elicited by stimulation of the lateral branch of the nerve when compared with the tension elicited by stimulation of the whole XIIth nerve was probably due to the absence of protrusive axons in the lateral branch of the nerve. Stimulation of the whole XIIth nerve activates axons innervating both protrusive and retrusive muscles, resulting in a weaker net retrusive force. 3. The contraction time of the tongue in response to medial branch stimulation (10.94 ms) was significantly faster than when the whole XIIth nerve (15.68 ms, P < or = 0.007) or lateral branch (13.36 ms, P < or = 0.05) was stimulated. The twitch contraction time of the tongue in response to whole XIIth nerve or lateral branch stimulation was not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Extraocular motor units: type classification and motoneuron stimulation frequency-muscle unit force relationships.

Extracellular and intracellular techniques were used to study single motor units of the abducens nucleus and lateral rectus muscle in the cat. Using a combination of two motor unit properties, the fusion frequency and an index of fatigability, the population of twitch motor units could be separated into 4 subgroups: fast fatigable (FF), fast fatigue resistant (FR), slow fatigable (SF) and slow fatigue resistant (S). Nontwitch motor units, a fifth subgroup (NT), formed 10% of the total studied population. The twitch tension and the maximum tetanic tension of the FF motor unit type were significantly stronger than all other motor unit types. The use of frequency varying stimulation patterns did not further differentiate the motor unit types. The relation between a series of single motoneuron stimulation frequencies and the resultant single muscle unit forces generated a slope defined as a motor unit's kt value. Motor units with low kt values had higher twitch tensions, higher maximum tetanic tensions, higher fusion frequencies and lower fatigue indices than motor units with high kt values. Motoneuron recruitment was tested by electrical stimulation of the medial rectus subdivision of the contralateral oculomotor nucleus. No correlations were seen between recruitment order and the mechanical parameters of the single abducens motor units.

Animals↗
PubMed1992

Enduring suppression of hippocampal long-term potentiation following traumatic brain injury in rat.

This study investigated changes in synaptic responses (population spike and population EPSP) of CA1 pyramidal cells of the rat hippocampus to stimulation of the Schaffer collateral/commissural pathways 2-3 h after traumatic brain injury (TBI). TBI was induced by a fluid percussion pulse delivered to the parietal epidural space resulting in loss of righting responses for 4.90-8.98 min. Prior to tetanic stimulation, changes observed after the injury included: (1) decreases in population spikes threshold but not EPSP thresholds; (2) decreases in maximal amplitude of population spikes as well as EPSPs. TBI also suppressed long-term potentiation (LTP), as evidenced by reductions in post-tetanic increases in population spikes as well as EPSPs. Since LTP may reflect processes involved in memory formation, the observed suppression of LTP may be an electrophysiological correlate of enduring memory deficits previously demonstrated in the same injury model.

Animals↗
PubMed1992

Mild dehydration induces echocardiographic signs of mitral valve prolapse in healthy females with prior normal cardiac findings.

This study was designed to investigate the hypothesis that mitral valve prolapse (MVP) can be induced after diuresis in women without the abnormality who have characteristic body habitus. Fifteen tall, slim, healthy female volunteers with a normal cardiac findings, echocardiogram, and history were investigated after mild diuresis with furosemide and after placebo. All subjects lost weight after furosemide and placebo administration; but mean weight loss was significantly greater after furosemide administration than after placebo administration. Echocardiography showed MVP in none of the 15 patients before treatment, in seven after administration of placebo, and in seven after administration of furosemide. Coaptation point prolapsed superior to the anulus in seven subjects with echocardiographically determined MVP. Left ventricular end-diastolic dimensions decreased significantly after placebo or furosemide administration in subjects in whom MVP developed compared with the measurement in those in whom MVP did not develop. Murmurs characteristic of MVP disappeared in all four rehydrated subjects and echocardiographic changes resolved in two of the five rehydrated subjects. Thus echocardiographically determined MVP can be induced by mild dehydration in women with phenotypic body habitus of MVP; changes may resolve with rehydration. Results suggest an explanation for variable physical examination findings in persons with MVP.

Adult↗
PubMed1992

Dobutamine stress echocardiography: a sensitive indicator of diminished myocardial function in asymptomatic doxorubicin-treated long-term survivors of childhood cancer.

Doxorubicin is an effective anticancer chemotherapeutic agent known to cause acute and chronic cardiomyopathy. To develop a more sensitive echocardiographic screening test for cardiac damage due to doxorubicin, a cohort study was performed using dobutamine infusion to differentiate asymptomatic long-term survivors of childhood cancer treated with doxorubicin from healthy control subjects. Echocardiographic data from the experimental group of 21 patients (mean age 16 +/- 5 years) treated from 1.6 to 14.3 years (median 5.3) before this study with 27 to 532 mg/m2 of doxorubicin (mean 196) were compared with echocardiographic data from 12 normal age-matched control subjects. Graded dobutamine infusions of 0.5, 2.5, 5 and 10 micrograms/kg per min were administered. Echocardiographic Doppler studies were performed before infusion and after 15 min of infusion at each rate. Dobutamine infusion at 10 micrograms/kg per min was discontinued after six studies secondary to a 50% incidence rate of adverse symptoms. The most important findings were that compared with values in control subjects, end-systolic left ventricular posterior wall dimension and percent of left ventricular posterior wall thickening in doxorubicin-treated patients were decreased at baseline study and these findings were more clearly delineated with dobutamine stimulation. End-systolic left ventricular posterior wall dimension at baseline for the doxorubicin-treated group was 11 +/- 1.9 mm versus 13.1 +/- 1.5 mm for control subjects (p less than 0.01). End-systolic left ventricular posterior wall dimension at the 5-micrograms/kg per min dobutamine infusion for the doxorubicin-treated group was 14.1 +/- 2.4 mm versus 19.3 +/- 2.6 mm for control subjects (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Cardiac teratogenicity of dichloroethylene in a chick model.

Trichloroethylene (TCE) and dichloroethylene (DCE) are related halogenated aliphatic hydrocarbon industrial solvents that are frequently found as drinking water contaminants. TCE has been implicated as a cardiac teratogen in an epidemiologic study and in a chick model. The purpose of this study was to determine whether DCE was also a cardiac teratogen in the chick embryo. Fertilized White Leghorn chick eggs (n = 418) were inoculated just above the embryo with 30 microL of a test solution on d 3 of incubation. Two control groups were studied: normal saline (n = 96) and the diluent for the DCE, mineral oil (n = 108). DCE was studied at three doses: 5, 20, and 25 microM (n = 76, 62, and 76, respectively). Eggs were coded with a seven-digit number to mask identity. Chicks were terminated on d 18 of incubation, and, after external inspection, hearts and great vessels were dissected macroscopically according to a detailed protocol. Abnormal hearts were reviewed and the diagnosis was agreed upon by three investigators before decoding the seven-digit number and photographing the abnormality. Some embryo death and subsequent tissue autolysis occurred in all groups, but, compared to controls, it was not significantly greater in the treatment group. However, combining all controls and all experimentals, significantly more (p = 0.02) embryonic death occurred in the experimental group. Noncardiac anomalies occurred in 17 embryos and were highest in the saline (four), 5 microM (four), and 20 microM (seven) DCE groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

High-frequency septal stimulation suppresses long-term potentiation (LTP) in the CA1 region of rat hippocampus.

The effects of high-frequency stimulation (HFS) of the medial septum/diagonal band (MSDB) on long-term potentiation (LTP) of CA1 extracellular field potentials were assessed in anesthetized rats. Ten rats received HFS of the Schaffer collateral pathway alone, and 10 received MSDB HFS 10 min prior to hippocampal HFS. Septal HFS suppressed LTP development assessed by change in population spike (PS) amplitude 60 min after hippocampal HFS (ANOVA, P less than 0.03). Septal inhibition of LTP development was most prominent when septal HFS had little direct effect on the CA1 PS. These results provide a novel demonstration of the functional heterogeneity of septohippocampal pathways and in vivo modulation of hippocampal LTP by HFS of natural afferent inputs.

Animals↗
PubMed1990

Increased birth prevalence of cardiac defects in Yuma, Arizona.

A systematic study was undertaken to estimate the birth prevalence of congenital heart disease because there was a clinical impression that a disproportionate number of cases occurred in Yuma, Arizona. Control data were obtained from Sierra Vista, Arizona, a region with similar demographic characteristics, and from the Baltimore-Washington Infant Study. Patients with chromosomal or syndromal associations were excluded. In the Baltimore-Washington Infant Study only echocardiographic and invasively documented cases were included. From 1983 to 1988 the birth prevalence was significantly higher in Yuma (10.5/1,000) than in Sierra Vista (5.4/1,000, p less than 0.0001). As assessed only by invasive or echocardiographic diagnosis, there was a higher birth prevalence of congenital heart disease in the study population (6.7/1,000) compared with both the Baltimore-Washington Infant Study (3.7/1,000, p = 0.0008) and Sierra Vista (4.6/1,000, p = 0.04). Families were interviewed to exclude cases in which the mother did not spend the month before conception and the first trimester in Yuma or Sierra Vista. The birth prevalence for Yuma (6.0/1,000) remained significantly greater than that for Sierra Vista (3.8/1,000, p = 0.03). The exclusion of cases in which the mother resided elsewhere suggests, but does not prove, that an environmental influence may have played a role in the increased birth prevalence of congenital heart disease in this community.

Arizona↗
PubMed1990

An association of human congenital cardiac malformations and drinking water contaminants.

During an informal study in 1973 it was noted that approximately one third of patients with congenital heart disease lived in a small area in the Tucson Valley. In 1981 groundwater for a nearly identical area was found to be contaminated with trichloroethylene and to a lesser extent with dichloroethylene and chromium. Contamination probably began during the 1950s. Affected wells were closed after discovery of contamination. This sequence of events allowed investigation of the prevalence of congenital heart disease in children whose parents were exposed to the contaminated water area as compared with children whose parents were never exposed to the contaminated water area. The contaminated water area contained 8.8% of the Tucson Valley population and 4.5% of the labor force. Using their case registry, the authors interviewed parents of 707 children with congenital heart disease who, between 1969 and 1987, 1) conceived their child in the Tucson Valley, and 2) spent the month before the first trimester and the first trimester of the case pregnancy in the Tucson Valley. Two random dialing surveys showed that only 10.5% of the Tucson Valley population had ever had work or residence contact, or both, with the contaminated water area, whereas 35% of parents of children with congenital heart disease had had such contact (p less than 0.005). The prevalence of congenital cardiac disease (excluding syndromes, children with atrial tachycardia or premature infants with patent ductus arteriosus) in the Tucson Valley was 0.7% of live births and with syndromes was calculated to be 0.82%. The odds ratio for congenital heart disease for children of parents with contaminated water area contact during the period of active contamination was three times that for those without contact (p less than 0.005) and decreased to near unity for new arrivals in the contaminated water area after well closure. The proportion of infants with congenital heart disease as compared with the number of live births was significantly higher for resident mothers in the contaminated water area than for mothers with no exposure. No other environmental agent could be identified that was localized to the contaminated water area, but one could have been missed. The data show a significant association but not a cause and effect relation between parental exposure to the contaminated water area and an increased proportion of congenital heart disease among live births as compared with the proportion of congenital heart disease among live births for parents without contaminated water area contact.

Adult↗
PubMed1990

Cardiac teratogenesis of trichloroethylene and dichloroethylene in a mammalian model.

Recent epidemiologic studies have demonstrated a greater than expected number of pediatric patients with congenital heart disease in areas where drinking water was contaminated by halogenated aliphatic hydrocarbons. Trichloroethylene, trichloroethane and dichlorethylene were the principal contaminants in the groundwater. A previous study of chick embryos demonstrated that when injected into the air sacs of fertilized eggs trichloroethylene produced more than three times the number of cardiac defects that are found in control embryos. This mammalian study demonstrates similar effects of trichloroethylene and dichloroethylene when applied under provocative circumstances (that is, solutions delivered through a catheter into the gravid uterus from an intraperitoneal osmotic pump) to the developing rat fetus in utero during the period of organ differentiation and development. Furthermore, the effect is dose dependent for both agents. Although only a very small number of congenital heart anomalies (3%) were found in the control group, 9% and 12.5% were found in the lower dose trichloroethylene and dichloroethylene groups and 14% and 21% in the higher dose groups, respectively (p less than 0.05). A variety of cardiac defects were found. Dichloroethylene appears to be at least as great a cardiac teratogen as trichloroethylene even though it was administered at a 10-fold lower concentration. These agents appear to be specific cardiac teratogens because only a single noncardiac anomaly was found. This study in a rat model demonstrates a dose-dependent relation between fetal exposure to trichloroethylene and dichloroethylene in utero during the period of organogenesis and the appearance of a variety of congenital cardiac defects.

Abnormalities, Drug-Induced↗
PubMed1990

Treatment of Kawasaki syndrome: a comparison of two dosage regimens of intravenously administered immune globulin.

Because intravenously administered immune globulin (IVIG) is effective in reducing the incidence of coronary artery aneurysms in Kawasaki syndrome when given at a dose of 400 mg/kg daily for 4 days, we undertook a multicenter clinical trial comparing two dosage regimens of IVIG. Patients were randomly assigned to receive IVIG at either 400 mg/kg daily for 4 days (22 patients) or 1 gm/kg as a single dose (22 patients). All patients received aspirin therapy, and all were enrolled within 7 days of onset of fever. The presence of coronary artery aneurysms was evaluated by means of two-dimensional echocardiography before infusion; at days 4 to 6, 14 to 21, and 42 to 49 after infusion; and at 1 year. Coronary artery aneurysms were detected in 3 of the 44 patients, including one patient receiving 400 mg/kg and two patients receiving 1 gm/kg (p value not significant). No giant aneurysms were detected. No major side effects occurred with either dosage regimen. Patients receiving the 1 gm/kg dose had a faster resolution of fever and were discharged from the hospital approximately 1 day sooner than the 400 mg/kg group (p = 0.01). Although the relatively small sample size in this trial does not allow for a more definitive statement regarding the occurrence of coronary artery aneurysms, it appears that the 1 gm/kg dose is associated with a more rapid clinical improvement and a shorter hospital stay.

Aspirin↗