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Biomedical subjects

I Arad

Publications and source records attributed to I Arad.

At least 19 recordsLinked to original sources
PubMed2004

The effect of wool vs. cotton head covering and length of stay with the mother following delivery on infant temperature.

Rectal temperature of 126 term infants was measured on admission to the nursery following variable periods of stay with the mother in the delivery room. Fifty-nine infants who wore woolen hats after delivery had higher rectal temperature than 67 infants whose head was covered by loosely applied cotton diapers (36.5+/-0.5 degrees C vs. 36.3+/-0.5 degrees C, respectively; p=0.03). Among them there were fewer infants who were admitted with rectal temperature 36 degrees C (12 vs. 26, respectively; p=0.03). In multiple regression analyses accounting for head covering with woolen hats, birth weight, gender, delivery room temperature and length of stay with the mother, only birth weight and head covering with woolen hats were significantly associated with rectal temperature at arrival in the nursery (p=0.002 and 0.03, respectively), and only head covering with cotton diapers was significantly associated with rectal temperature 36 degrees C (p=0.03). Our data imply that covering heads of term newborns with simple woolen hats may reduce or prevent heat loss following delivery, and that adequate warming of infants is achieved during prolonged stay with the mother.

Animals↗
PubMed2002

Cluster of neonatal infections in Jerusalem due to unusual biochemical variant of Enterobacter sakazakii.

Reported here is a cluster of infections due to a nitrate-negative variant of Enterobacter sakazakii, which occurred among premature neonates at the Hadassah Hospital, Mount Scopus, Jerusalem, in December 1999-January 2000. Pulsed-field gel electrophoresis showed cluster isolates to be identical but unrelated to previous systemic isolates recovered in 1993 and 1998. The organism was not isolated from infant formula powder, but it was recovered from prepared formula and from a kitchen blender. Elimination of the environmental focus, a change to factory-prepared infant formula, and isolation of affected infants terminated the event. Faecal carriage of Enterobacter sakazakii was observed for up to 18 weeks, emphasising the potential for cross-infection.

Bacteremia↗
PubMed2001

Statistical conservation laws in turbulent transport.

We address the statistical theory of fields that are transported by a turbulent velocity field, both in forced and in unforced (decaying) experiments. With very few provisos on the transporting velocity field, correlation functions of the transported field in the forced case are dominated by statistically preserved structures. In decaying experiments we identify infinitely many statistical constants of the motion, which are obtained by projecting the decaying correlation functions on the statistically preserved functions. We exemplify these ideas and provide numerical evidence using a simple model of turbulent transport. This example is chosen for its lack of Lagrangian structure, to stress the generality of the ideas.

Journal Article↗
PubMed2001

Spectrum of anisotropic exponents in hydrodynamic systems with pressure.

We discuss the scaling exponents characterizing the power-law behavior of the anisotropic components of correlation functions in turbulent systems with pressure. The anisotropic components are conveniently labeled by the angular momentum index l of the irreducible representation of the SO(3) symmetry group. Such exponents govern the rate of decay of anisotropy with decreasing scales. It is a fundamental question whether they ever increase as l increases, or they are bounded from above. The equations of motion in systems with pressure contain nonlocal integrals over all space. One could argue that the requirement of convergence of these integrals bounds the exponents from above. It is shown here on the basis of a solvable model (the "linear pressure model") that this is not necessarily the case. The model introduced here is of a passive vector advection by a rapidly varying velocity field. The advected vector field is divergent free and the equation contains a pressure term that maintains this condition. The zero modes of the second-order correlation function are found in all the sectors of the symmetry group. We show that the spectrum of scaling exponents can increase with l without bounds while preserving finite integrals. The conclusion is that contributions from higher and higher anisotropic sectors can disappear faster and faster upon decreasing the scales also in systems with pressure.

Journal Article↗
PubMed2001

Does parity affect the neonatal outcome of very-low-birth-weight infants ?

OBJECTIVE: To evaluate the impact of parity on the neonatal outcome (survival, bronchopulmonary dysplasia and severe intraventricular hemorrhage) of very-low-birth-weight infants, accounting for sociodemographic, obstetric and perinatal variables. STUDY DESIGN: One hundred and eleven singleton premature infants with birth weights of 750--1250 grams, delivered between 1990 and 1994 and treated in the Hadassah University Hospitals in Jerusalem, were evaluated. In the analyses, variables with statistically significant association with the outcome variables were identified and entered together with parity as explanatory variables in a logistic regression. The results were analyzed with and without the inclusion of respiratory distress syndrome, representing an index of initial illness severity, in the multivariate model. RESULTS: Neonatal mortality was higher in the 2--11 parity group when compared with first born infants. This association was of borderline statistical significance (OR=3.3; P=0.09), and was evident only upon exclusion of respiratory distress syndrome from the equation. There was no association between parity and the development of bronchopulmonary dysplasia. The risk for developing severe intraventricular hemorrhage was higher in offsprings of multiparous women (OR=4.6; P=0,08 for parity 2-4, and OR=7.6; P=0.03 for parity 5--11). Respiratory distress syndrome was significantly associated with all the outcome variables and, to some extent, masked the relevance of pregnancy duration. A short hospitalization period before delivery was associated with increased mortality and with higher incidence of severe intraventricular hemorrhage. High initial Apgar scores appeared protective against severe intraventricular hemorrhage and bronchopulmonary dysplasia. CONCLUSION: Our results demonstrate a trend for increased survival of first born premature infants when compared with offsprings of subsequent deliveries, and an association between advanced parity and the development of severe intraventricular hemorrhage. Confirmation of these data by other studies is required before resultant implications are considered.

Birth Weight↗
PubMed2001

Ectopic liver tissue within the umbilical cord.

A solid mass in the umbilical cord is a very rare finding. A neonate with isolated ectopic liver tissue found in the umbilical cord is reported. This is the first known such reported case.

Choristoma↗
PubMed2001

Neonatal bacteremia: patterns of antibiotic resistance.

OBJECTIVE: To determine the incidence and evaluate the antimicrobial-susceptibility patterns of bacterial infections in our neonatal units. DESIGN: Retrospective surveillance study. SETTING: The neonatal units of the Hadassah University Hospitals, Jerusalem, Israel. PATIENTS: All newborns admitted from January 1994 through February 1999. METHODS: The records of all patients with positive blood and cerebrospinal fluid cultures were reviewed. Bacteremia was considered early-onset (vertical) when occurring within the first 72 hours of life and late-onset (nosocomial) when occurring later. The prevalence and antibiotic-resistance patterns of vertically transmitted and nosocomially acquired strains were compared and studied over time. RESULTS: 219 of 35,691 newborn infants had at least one episode of bacteremia (6.13/1,000 live births). There were 305 identified organisms, of which 21% (1.29/1,000 live births) were considered vertically transmitted and 79% nosocomially acquired. The most common organism causing early-onset disease (29.2%) was group B streptococcus (0.38/1,000 live births), whereas coagulase-negative staphylococci (51%) were the most prevalent in late-onset disease. All gram-positive bacteria were susceptible to vancomycin. Most gram-positive organisms other than staphylococci were susceptible to ampicillin. Gram-negative organisms represented 31% of all isolates. Generally, there was a trend of increasing resistance to commonly used antibiotics among nosocomially acquired gram-negative organisms, compared to those vertically transmitted, with statistically significant differences for ampicillin and mezlocillin (P<.05 and P<.01, respectively). Over the years, a trend toward an increasing resistance to antibiotics was observed among gram-negative organisms. CONCLUSIONS: The trend of increasing bacterial resistance to commonly used antibiotics necessitates the implementation of a rational empirical treatment strategy, based on local susceptibility data, reserving certain agents for emerging resistant pathogens.

Cross Infection↗
PubMed2001

Early plasma creatinine values in discordant twins.

It has been suggested that impairment of placental perfusion prior to delivery may manifest in early postnatal increase of creatinine values. We hypothesized that the smaller of a discordant set of twins would have a higher initial plasma creatinine value and decided to measure early plasma creatinine levels in discordant twins in order to evaluate whether this value may serve as an index of impaired placental perfusion. Plasma creatinine, urea nitrogen and blood hematocrit values were simultaneously measured in 35 sets of twins during the first day of life. The sets of twins were divided into 2 groups according to birth weight difference. Thus, 18 sets of discordant twins with birth weight difference greater than 15% comprised the GT group and 17 sets of twins with birth weight difference less than or equal to 15% comprised the LE group. The differences between the values obtained within each group were analyzed using the Wilcoxon Signed Rank test. In the GT group the mean plasma creatinine level of the smaller twins was significantly higher than the level of the larger ones (p = 0.03), but there was no statistically significant difference between values obtained in twins of the LE group. The mean plasma urea level was higher in the larger twins of both groups, however only the difference in the GT group was statistically significant (p = 0.01). The mean hematocrit of the smaller twins was higher in both groups, but only the difference in the LE group was statistically significant (p = 0.02). Generally, there was a negative correlation between gestational age and early creatinine values. These results apparently support the notion that prenatal exposure to impaired placental perfusion may compromise the creatinine clearance of the fetus and result in higher early creatinine values. Since the creatinine values in our growth-retarded twins were within the normal range, no distinguishing line for evidence of a uterine-placental compromise could be drawn. Whether a certain early plasma creatinine value is suggestive or indicative of an intra-uterine hypoxic-ischemic insult, should be determined by documented instances of severe fetal compromise prior to delivery.

Birth Weight↗
PubMed2001

Enterobacter sakazakii infection in the newborn.

UNLABELLED: Enterobacter sakazakii, a Gram-negative bacillus, previously known as "yellow pigmented Enterobacter cloacae", is a rare cause of neonatal infection. We describe the detailed clinical presentation of two cases in whom E. sakazakii was isolated in our neonatal service during the course of 1 mo. These include one case of sepsis and meningitis complicated by cerebral infarction, and one case of sepsis. In addition, three cases of intestinal colonization were identified. The source of the organism was thoroughly sought and was found to be a blender in the milk kitchen that was used for preparation of the reconstituted powdered milk formula. CONCLUSION: Our paper adds clinical and laboratory information about the disease spectrum caused by this relatively rare organism and emphasizes the importance of a thorough search for the source of the infection.

Central Nervous System Infections↗
PubMed2000

Anomalous scaling in the anisotropic sectors of the kraichnan model of passive scalar advection

Kraichnan's model of passive scalar advection in which the driving (Gaussian) velocity field has fast temporal decorrelation is studied as a case model for understanding the anomalous scaling behavior in the anisotropic sectors of turbulent fields. We show here that the solutions of the Kraichnan equation for the n-order correlation functions foliate into sectors that are classified by the irreducible representations of the SO(d) symmetry group. We find a discrete spectrum of universal anomalous exponents, with a different exponent characterizing the scaling behavior in every sector. Generically the correlation functions and structure functions appear as sums over all these contributions, with nonuniversal amplitudes that are determined by the anisotropic boundary conditions. The isotropic sector is always characterized by the smallest exponent, and therefore for sufficiently small scales local isotropy is always restored. The calculation of the anomalous exponents is done in two complementary ways. In the first they are obtained from the analysis of the correlation functions of gradient fields. The theory of these functions involves the control of logarithmic divergences that translate into anomalous scaling with the ratio of the inner and the outer scales appearing in the final result. In the second method we compute the exponents from the zero modes of the Kraichnan equation for the correlation functions of the scalar field itself. In this case the renormalization scale is the outer scale. The two approaches lead to the same scaling exponents for the same statistical objects, illuminating the relative role of the outer and inner scales as renormalization scales. In addition we derive exact fusion rules, which govern the small scale asymptotics of the correlation functions in all the sectors of the symmetry group and in all dimensions.

Journal Article↗
PubMed1999

Neonatal outcome of inborn and transported very-low-birth-weight infants: relevance of perinatal factors.

OBJECTIVE: To compare the neonatal outcome (survival, intraventricular hemorrhage and bronchopulmonary dysplasia) of inborn and outborn very-low-birth-weight infants accounting for sociodemographic, obstetric and perinatal variables. STUDY DESIGN: Ninety-one premature infants with birth weights of 750-1250 g delivered between 1990 and 1994 in a hospital providing neonatal intensive care were compared with 76 premature babies delivered in a referring hospital. In the statistical analysis, variables with a statistically significant association with the outcome variables and dissimilar distributions in the two hospitals were identified and entered together with the hospital of birth as explanatory variables in a logistic regression. RESULTS: No statistically significant differences between the outcome variables of the two populations examined were observed, whether before or after accounting for the covariates. The odds ratios (outborns relative to inborns) were 1.18 for mortality, 1.25 for bronchopulmonary dysplasia and 1.53 for severe intraventricular hemorrhage. In the multivariate analyses, respiratory distress syndrome was significantly associated with mortality; both low birth weight and the presence of respiratory distress syndrome were associated with the development of bronchopulmonary dysplasia; the evolvement of severe intraventricular hemorrhage was associated with respiratory distress syndrome, initial low Apgar score, advanced multiparity and delivery at the 28-29th week compared to the 23rd-27th week. Antenatal steroid administration had a protective effect. CONCLUSION: Our results concur with the notion that a tertiary center is the optimal location for delivery of the high risk neonate. Improvement in medical and nursing care prenatally and at delivery and transportation, including frequent administration of antenatal steroids and earlier administration of surfactant prior to transportation, may minimize the disadvantage of delivery in a referring hospital.

Hospitals, General↗
PubMed1999

Correlation functions in isotropic and anisotropic turbulence: the role of the symmetry group.

The theory of fully developed turbulence is usually considered in an idealized homogeneous and isotropic state. Real turbulent flows exhibit the effects of anisotropic forcing. The analysis of correlation functions and structure functions in isotropic and anisotropic situations is facilitated and made rational when performed in terms of the irreducible representations of the relevant symmetry group which is the group of all rotations SO(3). In this paper we first consider the needed general theory, and explain why we expect different (universal) scaling exponents in the different sectors of the symmetry group. We exemplify the theory context of isotropic turbulence (for third order tensorial structure functions) and in weakly anisotropic turbulence (for the second order structure function). The utility of the resulting expressions for the analysis of experimental data is demonstrated in the context of high Reynolds number measurements of turbulence in the atmosphere.

Journal Article↗
PubMed1999

Premature singleton versus a twin or triplet infant death: parental adjustment studied through a personal interview.

Parental adjustment following the death of a premature singleton or multiple birth infant has hitherto been studied by mailed questionnaires or telephone survey. In the present study, using an in-depth personal interview, grief reactions and adjustment patterns of nine families who lost a singleton premature infant ('Single Group') were compared with those of nine families who lost one of a premature multiple birth cohort ('Multiple Group'). The interview was conducted 1-4 years after the death of the infant and evaluated specific areas or 'scales' of life adjustment, including individual feelings, relationship between husband and wife, and functioning at home and at work. There was no significant difference between the paternal and maternal level of adjustment of the two groups in any of the studied scales. A positive correlation was found between maternal and paternal grief reaction of the same family in the scales of individual feelings (r = 0.65), relationships between husband and wife (r = 0.70), and functioning at home (r = 0.57). Comparing the father's scale with the mother's scale revealed a significant difference only in the area of 'individual feelings'. The gestational age, maternal bonding during hospitalisation of the infant and the parental attendance at the event of death were significantly associated with the process of parental adjustment. The results of this study support previous reports of similar parental reactions following the demise of a premature singleton or multiple birth infant. Since societal environment may not recognise the need for consolation of these families, care, compassion, and sensitivity should be encouraged in dealing with these parents at the time of their infant' death, and for a long time thereafter.

Adaptation, Psychological↗
PubMed1999

Low frequency spontaneous fluctuations in tissue blood volume in neonates.

Low frequency spontaneous fluctuations in tissue blood volume (BV) which originate from the activity of the autonomic nervous system were studied in the toes of healthy adults and in the feet of preterm and full-term neonates. Fluctuations of cardiac-induced blood volume changes (AM) were also investigated using photoplethysmography, the measurement of changes in light absorption by tissue and its constituents. Both fluctuations showed right-left correlations, which indicates mediation of central origin. The average right-left correlation coefficient for adults was significantly higher than that for neonates, probably due to incomplete maturation of the autonomic nervous system for some of the neonates.

Adolescent↗
PubMed1998

Coma in a premature infant associated with the transdermal absorption of propylene glycol.

A case of propylene glycol intoxication in a premature infant is reported. The infant went into a state of coma after treatment for burns with antiseptic dressings. Cessation of the topical treatment resulted in complete recovery. An exceptionally high level of the dressings' solvent, propylene glycol, found in the urinary chromatogram, was believed to be the causative agent. It is suggested that topical preparations containing propylene glycol should not be used in premature infants during the first weeks of life.

Coma↗
PubMed1997

Late-appearing diaphragmatic hernia following resolution of right pleural effusion.

A case of late-appearing congenital diaphragmatic hernia in a premature infant with previously normal chest X-ray is reported. Pleural effusion accumulation and resolution preceded herniation of the liver to the right hemithorax and development of respiratory symptoms. Chest X-ray, ultrasound and computed tomography of the chest were useful in establishing the correct diagnosis. Pleural effusion without obvious cause should alert the paediatrician to the possibility of this rare condition.

Female↗