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Biomedical subjects

L Stern

Publications and source records attributed to L Stern.

At least 91 records · Page 5Linked to original sources
PubMed1982

The value of effectiveness of neonatal intensive care: its relationship to perinatal mortality and morbidity.

Evidence has accumulated from a number of sources regarding the efficacy of neonatal intensive care in effecting overall reductions in neonatal mortality. Such effectiveness is in direct proportion to the degree of organization of the systems that are used to provide it and their relationship to the regional organization and distribution of such neonatal intensive care centers. The expectations that such neonatal intensive care practices would, however, result in an increased morbidity, particularly in relationship to handicap and developmental delay, is not supported by any concrete evidence. On the contrary there is an increasing suggestion that the effectiveness of such practices and the centers in which they are carried out is reflected in an overall decline in the incidence of severity of morbidity and that the practices themselves have resulted not only in greater numerical survivors but in a better overall quality of those infants as well. This relationship is certainly for surviving newborn infants born at term and for low birthweight infants in excess of 1500 grams. It needs to be more critically evaluated in the smaller low birth weight infant in whom survival after protracted illness is associated in greater frequency with a variety of major and minor handicapping conditions.

Birth Weight↗
PubMed1981

In vivo assessment of the teratogenic potential of drugs in humans.

The difficulties in assessing the teratogenic potential of drugs used during pregnancy have been made evident by experiences with thalidomide and diethylstilbestrol (DES). In the case of thalidomide, the drug's ability to cause phocomelia tended to be species specific, and thus animal studies were unreliable indicators of teratogenicity in humans. With DES, the delayed appearance of injury, almost a generation after birth, indicates that short-term studies may fail to reveal serious effects. In both cases only the otherwise rare occurrence of the condition led to the suspicion of a cause-and-effect relationship. Although wide-spread use of drugs such as LSD, heroin, and marijuana has necessitated assessment of their teratogenic potential, a controlled investigation of their effects has so far been impossible to conduct. Both tobacco and alcohol have been associated with adverse effects on the fetus and neonate, but the precise mechanisms by which these effects occur are as yet unclear. There is also reason for concern about the teratogenic potential of environmental pollutants such as organic mercury compounds, lead, and radiation. Furthermore, the fetus may potentially be harmed if a particular drug is not administered (eg, insulin for diabetes during pregnancy). In the final analysis, any potential benefits of therapy for the mother must be weighed against known and unknown risks to the infant. Rational management requires an understanding of the physiologic and pharmacologic principles involved in each case and careful and judicious selection of drug therapy.

Abnormalities, Drug-Induced↗
PubMed1980

Effect of selective coronary arteriography on left ventricular volumes and ejection fraction in man.

This study was performed to assess the influence of selective coronary arteriography on left ventricular volumes and ejection fraction in man. In 30 patients with assorted cardiac diseases, left ventricular end-diastolic and end-systolic volumes and ejection fraction were quantitated immediately before and after selective coronary arteriography. In 19 patients (Group A), contrast left ventriculography was performed immediately before and after selective coronary arteriography. In the remaining 11 patients (Group B), multigated equilibrium blood pool imaging was performed just before and after coronary arteriography. In both groups, mean systemic arterial pressure and heart rate did not change from just before the first to immediately before the second assessment of left ventricular volumes and ejection fraction, but left ventricular end-diastolic pressure increased. End-diastolic and end-systolic volume indexes, and ejection fraction did not change from just before to immediately after selective coronary arteriography. Therefore, selective coronary arteriography (1) consistently causes an increase in left ventricular end-diastolic pressure but (2) exerts no effect on left ventricular volumes and ejection fraction, even in patients with severely compromised left ventricular function.

Adult↗
PubMed1980

Altered protein synthesis and creatine kinase in breast muscle cell cultures from dystrophic chick embryos.

The total protein synthesis (TPS), myosin synthesis (MS) and creatine kinase (CK) levels in muscle cell cultures obtained from 400 normal (strain 454) and 400 dystrophic chick embryos (strain 455) were investigated. The cultures were obtained from breast muscles of 12 day chick embryos by dissociation in 0.25% trypsin, preplating and plating of 5 x 10(5) floating cells on gelatin coated dishes in Minimal Essential Medium, 10% horse serum and 2% chick embryo extract. After 6 days, when electron-microscopic studies demonstrated good muscle differentiation, cell cultures were labeled with [3H]leucine. TPS and MS, respectively, showed 85% and 65% increases in breast muscle cell cultures from dystrophic chick embryos. The half-life times for total protein and myosin from dystrophics were 19 and 32 hr, respectively as compared with 36 and 48 hr from controls. Noncollagen protein content (NCP) showed 27% decrease in postfusion stage (12 days) of cell cultures from dystrophics. The CK level showed 30% lower values in the cells from dystrophics but 50% higher values in their culture medium. The addition of leupeptin plus pepstatin (50 microgram/ml) to these cultures resotred NCP content, total protein and myosin turnover to normal values and significantly increased TPS and MS. The addition of diphenylhydantoin (DPH) (20 microgram/ml) to cell cultures from dystrophics did not change the NCP content nor the turnover for total protein and myosin but significantly increased TPS, MS and CK while medium CK significantly decreased. The addition of leupeptin plus pepstatin or DPH to muscle cell cultures from normal chick embryos also significantly stimulated TPS and MS.

Animals↗
PubMed1980

Motor nerve conduction in intravenous regional anaesthesia with bupivacaine hydrochloride.

Motor nerve conduction (MNC) from proximal and distal points of the median and ulnar nerve was examined in 14 patients receiving a total of 29 i.v. regional anaesthetics (IRA) with bupivacaine hydrochloride in doses ranging from 100 to 300 mg. Conduction was tested during and following vascular obstruction, until MNC returned to pre-IRA value. After 20 min of obstruction, MNC was unobtainable in most patients, an effect which was dose-related. The action of bupivacaine on MNC persisted for up to 3 h after cuff release, depending on the dose, and paralleled voluntary movements. MNC block began at the proximal point of both nerves, the median nerve being affected earlier. Based on the clinical and electrical findings, bupivacaine 200 mg proved to be optimum dose for producing safe and prolonged IRA.

Anesthesia, Conduction↗
PubMed1980

Prolonged effect of bupivacaine hydrochloride after cuff release in i.v. regional anaesthesia.

Bupivacaine hydrochloride 0.25% and 0.50% solutions, were administered 115 times by the i.v. regional route to 64 surgical patients and in 38 subjects suffering from pain syndromes. The clinical effects were limb numbness up to 20 h following cuff release, while analgesia and weakness of the limb muscles were evident 5 h after the tourniquet. Clinical and electrophysiological findings revealed a dose relationship of the effects. Toxic signs were noted in three patients in whom the cuff was released in a one-step fashion. In 11 patients, mean arterial plasma concentrations of bupivacaine reached 3.7 micrograms ml-1 after administration of 0.5% bupivacaine 40 ml, 5 min after final cuff release, and decreased gradually thereafter. In selected conditions which do not require a bloodless field and in certain intractable pain states, i.v. regional anaesthesia with high-dose bupivacaine (200 mg of 0.5% solution) may be a simple and effective technique.

Adult↗
PubMed1980

Contribution of radio-electrocardiography in the rehabilitation of CVA patients.

Seventy-eight patients with cerebrovascular accidents (CVA) underwent radio-electrocardiographic evaluation (RECG) and blood pressure measurements, together with clinical observation during physical therapy and rehabilitation. Twenty-six out of 78 CVA patients had pathological RECG. Of the total, 20 (25.6%) patients had a history of ischemic heart disease prior to CVA, 11 of them manifested abnormalities on the radio-electrocardiography, suggesting myocardial ischemia, arrhythmia, or severe heart rate changes. Out of 58 patients without any cardiac history or complaints before CVA, 15 (25.9%) showed pathological tracings during active therapy. In 20 patients out of 26 with pathological RECG, marked improvement was seen in repeated telemetric evaluation after drug and/or physical therapy was changed. In 42 hypertensive patients, 12 (28,5%) were found to suffer from marked elevation of the diastolic blood pressure during active physical training. Since the energy cost of ambulation in hemiplegics is much higher than in people without motor disabilities, RECG helps us in the detection of cardiac disorders, assessement of myocardial performance, and prescription of optimal physical and/or drug therapy in CVA patients.

Aged↗
PubMed1979

Effect of ethane-1-hydroxy-1,1-diphosphonate and vitamin D on bone mineralization.

Administration of large quantities of ethane-1-hydroxy-1,1-diphosphonate to growing chicks resulted in a decrease in percent bone ash and an increase in percent osteoid. The degree of inhibition of bone mineral accumulation was a function of both duration and quantity of ethane-1-hydroxy-1,1-diphosphonic acid administration. The inhibition of bone mineral accumulation could be partially corrected with administration of 1,25-dihydroxyvitamin D3. Administration of high levels of ethane-1-hydroxy-1,1-diphosphonate also resulted in inhibition of intestinal calcium absorption. This could be reversed or prevented by the administration of 1,25-dihydroxyvitamin D3.

Animals↗
PubMed1979

Assessment of ventilation-perfusion inequality by aADN2 in newborn infants.

The contribution (Qo/Qt) of gas-filled air spaces with reduced ventilation-perfusion ratio (VA/Qc) to the production of total venous admixture in nondistressed premature infant and newborn infants with transient tachypnea was assessed by the aADN2 and AaDo2. The mean value for Qo/Qt in both nondistressed prematures and infants with transient tachypnea was 0.08. In both groups this represented about 30% of total venous admixutre.

Carbon Dioxide↗