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Biomedical subjects

J M Milstein

Publications and source records attributed to J M Milstein.

At least 55 records · Page 3Linked to original sources
PubMed1985

Effect of hydration on experimentally induced cerebral edema.

Although fluid restriction is often used to manage cerebral edema, there have been no controlled studies which demonstrate its benefit. We evaluated the effects of dehydration and overhydration on the development of cerebral edema in rats subjected to triethyltin poisoning or anoxic ischemia. Four days after triethyltin poisoning, the brains of control rats receiving maintenance hydration had a mean percentage of water of 79.56%; dehydration (5% of body weight) and overhydration groups were not statistically different at 79.95% and 79.86%, respectively. Forty-seven hours after an anoxic-ischemic insult consisting of unilateral carotid artery ligation and subsequent exposure to a 4% oxygen atmosphere for 30 min, the percentage of water in control rats was 79.12%; dehydration (13% of body weight) and overhydration groups were 79.10% and 79.16%, respectively. Histopathologic analysis of brain sections did not differentiate the hydration groups (triethyltin model only). Thus, cerebral edema was not altered by hydration status in either poisoned or ischemic animals.

Animals↗
PubMed1985

Sleep patterns in nonambulatory boys with Duchenne muscular dystrophy.

Sleep patterns and respiratory function during sleep were studied in five nonambulatory boys with Duchenne muscular dystrophy to clarify why patients with this disease awaken frequently at night. It was hypothesized that hypoxemia during sleep due to severe restrictive lung disease might cause nighttime arousals. Each boy underwent electroencephalography, electro-oculography and electromyography. Also determined were arterial oxyhemoglobin saturation, airflow from the nose and mouth, chest and abdominal excursions, and carbon dioxide tension of exhaled breaths. All five subjects had pulmonary function abnormalities consistent with severe restrictive lung disease and respiratory muscle weakness but none had evidence of respiratory failure or cor pulmonale. The boys awakened three times more frequently than age-matched published norms and experienced sleep stage shifts twice as often as normal children. Rapid-eye movement (REM) sleep as a proportion of total sleep was significantly reduced; sleep stage I was increased compared to normal values. No subject developed oxyhemoglobin desaturation during sleep. End-tidal CO2 tensions rose during sleep stages I, II and V (REM) in association with reduced chest wall excursion, suggesting transient episodes of mild hypoventilation which were not associated with arousals. Sleep fragmentation, frequent arousals and REM sleep deprivation occur in some boys with Duchenne muscular dystrophy but are not associated with significant disorders in breathing during sleep.

Adolescent↗
PubMed1984

Pulmonary vascular response to digoxin in newborn lambs.

The effects of digoxin on pulmonary vascular resistance (PVR) were evaluated in normoxic (N) and hypoxic (H) newborn lambs with normal and elevated PVR, respectively. Lambs were anesthetized and instrumented to enable continuous measurement of mean pulmonary arterial pressure (PPA), mean left atrial pressure (PLA), mean pulmonary blood flow (Qp), and mean aortic pressure (PAO). Digoxin (10-20 micrograms/kg) was injected via central venous catheters in 11 N lambs and 4 H lambs. Under N conditions, baseline PVR was equal to 0.12 mm Hg/ml/min/kg, PPA was 33 mm Hg, PLA was 6 mm Hg, Qp was 235 ml/min/kg, and PAO was 69 mm Hg. Following digoxin, mean PVR increased by 24% (P less than 0.001) and PPA increased by 23% (P less than 0.001) for an average duration of 199 sec while QP increased by 5% (P less than 0.02) and PLA was constant suggesting a direct vasoconstrictive effect. Under H conditions, baseline PVR was equal to 0.26 mm Hg/ml/min/kg, PPA was 58 mm Hg, PLA was 4 mm Hg, Qp was 208 ml/min/kg, and PAo was 65 mm Hg. Following digoxin, mean PVR, Qp, PLA, and PAo did not change appreciably although PPA had a uniform increase of 5% (P less than 0.001). The blunted response may suggest that either the pulmonary vascular bed was maximally constricted or that digoxin and hypoxia share a common mechanism. In conclusion, digoxin has a direct pulmonary vasoconstrictor action in newborn lambs. Because of its short duration, this action probably should not alter the clinical use of this drug in newborn humans.

Animals↗
PubMed1983

Cerebral vascular resistance in premature infants.

The cerebral vascular bed is a low-resistance system in which continuous forward or advancing diastolic blood flow can be demonstrated. This advancing flow increases progressively with vasodilation and decreases or is absent when vessels are constricted. By using the Doppler technique, an indirect assessment of vascular resistance can be made by comparing systolic and diastolic flow amplitudes. We examined nine premature infants and found that respiratory acidosis alone, or hypoxia and acidosis in combination, resulted in significant vasodilation. This effect was reversible when arterial blood gas tensions returned to normal. The results indicate that within a physiologic range of BPs, premature infants with acute respiratory distress can alter their cerebral vascular resistance in response to spontaneous changes in blood gas tensions.

Acidosis↗
PubMed1982

Hypertrophic cardiomyopathy is a component of subacute necrotizing encephalomyelopathy.

Twelve patients, ranging from the neonatal period through adolescence, with subacute necrotizing encephalomyelopathy (Leigh disease) were studied. Autopsies of these patients demonstrated an associated hypertrophic cardiomyopathy in seven; of these, four had asymmetric septal hypertrophy. In two patients, the cardiac lesion was observed by premortem echocardiograms. The common occurrence of a cardiac lesion emphasizes the probable systemic nature of SNEM and may serve to segregate these patients into two groups. Because of the involvement of the two systems, we suggest that SNEM may have some relation to a variety of other cardioneurologic syndromes.

Adolescent↗
PubMed1980

Pulmonary vascular histamine receptors in newborn and young lambs.

Histamine H1- and H2-receptor-mediated pulmonary vascular responses were evaluated in six newborn and three 4-wk-old lambs. Base-line pulmonary vascular resistance (PVR) was elevated via alveolar hypoxia. Changes in PVR were then determined over a range of 0.001-1.0 microgram/kg of histamine. Multiple phases of relaxation of PVR were observed in all lambs. Two distinct plateaus of relaxation occurred between 0.001 and 0.075 micrograms/kg of histamine. The response at the first and major plateau was abolished by the H1-receptor antagonist, diphenhydramine. The second and smaller relaxation appeared to be attenuated by the H2-receptor antagonist, metiamide. Qualitatively similar results were obtained in the older lambs. Larger doses of histamine, 0.1-1.0 microgram/kg, produced further, but variable decreases in PVR as well as changes in systemic blood pressure. Our findings in newborn lambs are in contrast to those in adults where less sensitive H1-receptors mediate pulmonary vasoconstriction.

Animals↗
PubMed1980

Prognosis of intracranial hemnorrhage in neonates.

Eleven of 21 infants with intracranial hemorrhage documented by computerized axial tomography survived and have had serial developmental assessments. Six of nine infants with intraventricular hemorrhage (IVH) are developing normally, as is one of two infants with isolated subtentorial hemorrhage. According to our system for grading the severity of IVH, severe IVH correlated best with mortality and less well with developmental delay in survivors. Contrary to past impressions, IVH, even if severe, does not uniformly lead to a poor developmental outcome in surviving infants.

Age Factors↗
PubMed1979

Increased systemic vascular resistance in neonates with pulmonary hypertension.

The time necessary for aortic diastolic pressure to decrease to 50 percent of an initially selected value after dissipation of the dicrotic notch (T 1/2) was determined in newborn infants with and without pulmonary hypertension. The mean T 1/2 was 671 +/- 167 msec in seven infants with clinical evidence of pulmonary hypertension and documented right to left ductus arteriosus shunting; 849 +/- 243 msec in nine infants with clinical evidence of pulmonary hypertension but no documented right to left ductus arteriosus shunting; and 457 +/- 66 msec in eight infants with hyaline membrane disease and no clinical evidence of pulmonary hypertension or a patent ductus arteriosus. The mean T 1/2 values in the former two groups were significantly different from that in the group with no pulmonary hypertension (P less than 0.01). An evaluation of factors affecting T 1/2 leads to the conclusion that the patients with pulmonary hypertension had increased systemic vascular resistance as well. This finding has important diagnostic, etiologic and therapeutic implications.

Ductus Arteriosus↗
PubMed1979

Assessment of patent ductus arteriosus shunting using diastolic pressure analysis.

Ductal shunting significantly affected the time necessary for aortic diastolic pressure to fall to one-half an initially selected value (t1/2). Fourteen premature infants with clinical evidence of left-to-right ductal shunting had a mean t1/2 of 277 msec (range 133 to 383 msec) compared with a mean t1/2 of 455 msec (range 332 to 567 msec) in 14 neonates with no clinical evidence of ductal shunting (P less than 0.01). Seven older infants with ductal shunting confirmed at cardiac catheterization had a mean t1/2 of 360 msec (range 240 to 392 msec). Infant catheterization data and animal studies are suggestive of an inverse relationship between the magnitude of shunt and the t1/2. The t1/2 determined by diastolic pressure analysis is a useful method for serial evaluation of ductus arteriosus shunting.

Child, Preschool↗
PubMed1979

Pulmonary vasodilator action of tolazoline.

The pulmonary vasodilator action of tolazoline in newborn lambs was shown to be mediated via histamine receptors. Maximal changes in pulmonary vascular resistance, deltaPVR, were calculated as percents of the base line value, %deltaPVR. The mean %deltaPVR after tolazoline, 1 mg/kg, was -25 +/- 4% for eight lambs. Four lambs then received the histamine H1 receptor antagonist, diphenhydramine, and the mean %deltaPVR due to tolazoline was -12 +/- 4%. Four lambs received the H2 receptor antagonist, metiamide, and the mean %delta PVR due to tolazoline was -18 +/- 5%. After both H1 and H2 antagonists, the mean %deltaPVR due to tolazoline was +6 +/- 8%. Therefore, both histamine H1 and H2 receptors were involved in the vasodilator response to tolazoline.

Animals↗
PubMed1977

Computerized axial tomography of the brain in neonates and young infants.

Twenty critically ill infants with abnormal head growth and/or seizures underwent CAT of the brain. Signs of birth asphyxia or respiratory distress were present in all. Six out of ten infants with abnormal size of the head had abnormal CAT scans. Nine out of ten infants with seizures had abnormal scans. Abnormalities included hydrocephalus, intraventricular hemorrhage, cerebral edema, subarachnoid hemorrhage and porencephaly. Six infants required neurosurgical procedures. Development at two to 15 months of age in the 19 surviving infants was normal in nine, suspect in eight, and severely delayed in two patients. Until the prognosis of the various CNS disorders discussed is clearly defined, aggressive management appears indicated.

Asphyxia Neonatorum↗