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Biomedical subjects

H L Cohen

Publications and source records attributed to H L Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1991

Power spectral analysis of the baroreflex in neonatal swine.

The baroreflex was observed in neonatal swine as young as 4 h of age. Bolus injections of Na nitroprusside (NP) and phenylephrine (PE), induced changes in blood pressure and elicited changes in both heart rate and in cervical sympathetic and splanchnic discharge; changes in sympathetic discharge were reflected in altered power spectral magnitude. Measures of heart rate showed that the magnitude of the PE-induced decreases was positively correlated with increasing postnatal age. The results indicate that the baroreflex, as indicated by changes in sympathetic discharge and heart rate, is present in early neonatal swine.

Aging↗
PubMed1991

The swallowed toothbrush: a radiographic clue of bulimia.

Swallowed toothbrushes were noted in the esophagus of one teenager and the stomach of two others with bulimia. The presence of a toothbrush in the lumen of the gastrointestinal tract should make the radiologist suspicious of bulimia/anorexia nervosa. A toothbrush shows a characteristic radiographic image with parallel rows of short metallic radiodensities due to the metallic plates that hold the bristles in place.

Adolescent↗
PubMed1991

EEG characteristics in males at risk for alcoholism.

Baseline EEG activity was recorded with eyes closed in 15 males, aged 19 to 24 at risk (HR = high risk) for the development of alcoholism and 15 matched controls (LR = low risk). Four EEG frequency bands were examined: slow alpha (7.5-10 Hz), fast alpha (10.25-12.75 Hz), slow beta (13-19.5 Hz) and fast beta (19.75-26 Hz). The HR and LR groups were compared on four measures of EEG activity for each frequency band: band power, absolute and relative area and laterality differences. Statistical analysis of the data via ANOVA revealed no significant difference between the HR and LR groups for any comparison. The results indicate that EEG measures prior to alcohol administration do not effectively discriminate between individuals at high and low risk for alcoholism.

Adult↗
PubMed1991

Respiratory modulation of sympathetic activity in neonatal swine.

Spontaneous efferent sympathetic activity (cervical sympathetic and splanchnic nerves) was recorded simultaneously with efferent phrenic discharge, with aortic pressure, and with the electrocardiogram in less than 1- to 51-day-old neonatal swine anesthetized with Saffan (alfaxalone). Power spectral analyses of sympathetic discharge revealed a frequency range of 4-36 Hz, with peaks distributed in four regions of the spectrum (4-6 Hz, 8-15 Hz, 16-22 Hz, and 28-36 Hz). Inspiratory modulation was readily apparent since sympathetic power spectral energy was greatest during the time of phrenic activity. Alterations in pulmonary afferent inputs (e.g., lung inflation tests and/or vagotomy) altered both phrenic and sympathetic activity. Use of the respiratory-cardiac modulation ratio indicated that respiratory modulation of sympathetic activity was greater than cardiac modulation. Complex afferent inputs, i.e., fictive Valsalva maneuver, indicated an immaturity of integration within the cardiovascular regulatory system. The adult patterns of blood pressure changes and heart rate responses were delayed until approximately 1 mo of age. Calculations of Valsalva ratios (ratio of maximal R-R interval to minimal R-R interval) indicated delayed onset of heart rate responses, reflecting the maturation of cardiovascular reflexes during the neonatal period.

Aging↗
PubMed1991

Normal length of fetal kidneys: sonographic study in 397 obstetric patients.

This study was done to measure normal lengths of fetal kidneys sonographically during pregnancy. Knowledge of these measurements may allow earlier diagnosis of a variety of abnormalities. The greatest length of each of 498 kidneys in 397 consecutive fetuses between 18 and 41 weeks gestation was measured on sonograms. Gestational ages were determined by last menstrual period and biometry; significant discrepancies led to case exclusion. Abnormal fetuses, twins, offspring of diabetic mothers, and fetuses with renal pelvic dilatation of 4 mm or greater were excluded to avoid any questionable measurements. The results show that mean lengths are greater and confidence intervals are wider than previously reported. Renal lengths are similar to those reported in premature and full-term neonates. Strong correlation exists between renal length and gestational age, determined by biparietal diameter, femoral length, and abdominal circumference, and an average of the three. No significant difference was found between right and left renal lengths in fetuses in whom both kidneys were imaged. Average renal lengths are significantly different when compared across the range of gestational ages (p less than .001). No correlation is seen (r = .00) between parental height or weight and fetal renal length. Our results show that fetal renal lengths are longer than previously reported.

Female↗
PubMed1990

Effects of anesthesia on efferent phrenic activity in neonatal swine.

The effects of two levels of Saffan anesthesia (standard recording level: 2-4 mg/kg/min, and 10X recording level) and a single level of pentobarbital (5 mg/kg) on the power spectral density of efferent phrenic discharge were investigated in piglets aged from less than 1 day to 50 days. The phrenic high frequency oscillation (HFO) was present in decerebrate, unanesthetized piglets and in piglets anesthetized with Saffan, albeit reduced at 10 times recording level, but was absent under pentobarbital. The results indicate that Saffan does not have a significantly depressant effect on the phrenic HFO in developing swine.

Alfaxalone Alfadolone Mixture↗
PubMed1990

Calcified neonatal renal vein thrombosis demonstration by CT and US.

Two cases of calcified renal vein thrombosis (RVT) were diagnosed, incidentally, within the first weeks of life. The CT images present the virtually diagnostic branching pattern of calcification that has been previously noted on pathology specimen radiographs. The CT and US images show peripheral renal vein, central renal vein and inferior vena cava calcification conforming to the two theoretical origins of intravascular calcification. The patients had normal laboratory results and no symptoms related to renal vein or inferior vena cava thrombi.

Calcinosis↗
PubMed1990

Ovarian volumes measured by US: bigger than we think.

Authors have disputed the classic normal ovarian volume measurement of 6 cm3 without reference to a study with a large number of patients. To determine normal sonographic measurements, 762 consecutive female patients were examined. Satisfactory measurements of 1,157 ovaries in 725 of these patients were obtained. Average ovarian volumes of 9.8, 5.8, and 3.0 cm3 were obtained for the menstruating, postmenopausal, and premenarchal groups, respectively. These volumes were significantly different for these three menstrual groups (P less than .0001). Significant volume differences were noted when measurements were grouped by decade of life. Volumes peaked in the 3rd decade and declined over the subsequent four decade groups. A significant average volume difference was noted between pregnant (11.1 cm3) and non-pregnant (9.4 cm3) menstruating patients (P less than .0001). No significant differences in volume were noted between right and left ovaries or when the variables of weight, presence of a leiomyomatous uterus, or phase of the menstrual cycle were evaluated.

Adolescent↗
PubMed1990

Ultrasound of the septum pellucidum. Recognition of evolving fenestrations in the hydrocephalic infant.

Fenestrations of the septum pellucidum may be noted in hydrocephalic infants. This finding and its changing image was noted in six premature infants evaluated by neurosonography over time periods ranging from weeks to months. Breaks in the septum were noted to occur from 14 days to 23 weeks after the sonographic diagnosis of hydrocephalus. Some of these fenestrations were noted to increase in size and/or become bilateral over time. The awareness of evolving fenestrations and their late-stage images helps avoid confusion with partial and complete agenesis of the septum pellucidum and their possible associated neuroanatomical abnormalities.

Cerebral Hemorrhage↗
PubMed1990

Unusual observations on hypermagnesemic levels and cardiorespiratory effects in neonatal swine.

Mg is being used as a therapeutic agent in different clinical conditions, i.e. preeclampsia or eclampsia, and as a tocolytic agent to prevent premature delivery. For these reasons we decided to systematically investigate the cardiovascular and respiratory effects of excess Mg in 25 piglets less than 1 day to 3 months of age, lightly anesthetized with Saffan, tracheotomized, paralyzed with C-10 and artificially ventilated on 100% O2. A 1.0 M infusion of MgCl2 was given for 15-60 min, and arterial plasma samples were drawn before and at the end of the infusion for the determination of plasma Mg and Ca levels. Phrenic nerve activity was recorded monophasically simultaneously with arterial blood pressure, electrocardiogram, end-tidal CO2 and intratracheal pressure on a dynograph and on analog tape. In a subset of experiments (n = 6), spontaneous ventilation was monitored in piglets of different ages to determine the Mg concentration at which spontaneous ventilation ceased. Blood gases were measured at 45-min intervals, as well as both immediately before and after the MgCl2 infusion, and pCO2 and pH were maintained within normal limits. As a consequence of the high plasma concentration of Mg, mean arterial pressure and heart rate declined, and the inspiratory duration significantly decreased. Our results indicate that young piglets can survive high levels of plasma Mg (greater than 14 mM).

Animals↗