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Biomedical subjects

Y Amitai

Publications and source records attributed to Y Amitai.

At least 19 recordsLinked to original sources
PubMed2004

Association of parental consanguinity with congenital malformations among Arab newborns in Jerusalem.

The aim of this work was to determine the impact of parental consanguinity on congenital malformations in a mixed urban and rural Arab community in Jerusalem, Israel. Arab mothers admitted to four hospitals in west Jerusalem were interviewed after delivery. Demographic and obstetric data were recorded. Neonatal data were extracted from the medical records of the nursery. When malformations were suspected, a 4- to 10-month follow up was achieved for confirming the diagnosis. Of 561 infants, 253 (45%) were born to consanguineous couples. The incidence of major congenital malformations in the offspring was 8.7, 7.1 and 2.6% in cases of first cousins, all consanguineous, and non-consanguineous couples, respectively. No association was found between parental consanguinity and prematurity (p = 0.357) or low birth weight (p = 0.589). Parental consanguinity was also associated with an increased incidence of death in previous siblings (p < 0.000). The increased incidence of congenital malformations and infant mortality in cases of inbreeding prompt the necessity of establishing programs to avoid these complications in the offspring.

Adult↗
PubMed2002

Dietary folate and the incidence and prevention of neural tube defects: a proposed triple intervention approach in Israel.

The efficacy of folic acid in the prevention of neural tube defects depends on whether it is administered to women during the period surrounding conception. Optimizing the compliance of women at this critical time is a public health challenge. We assess the need for formulation of public health policy in Israel aimed at enhancing folate intake by women, examine policy implementation strategies, and review policy options regarding the approaches to enhance folic acid intake.

Adult↗
PubMed2001

Five decades of trends in anemia in Israeli infants: implications for food fortification policy.

OBJECTIVE: To describe the secular trends in the prevalence rates of iron-deficiency anemia (IDA) in infants in Israel, identify population group differences and assess the effectiveness of the 1985 Public Health directives on iron supplementation and avoidance of cow's milk in the first year of life. DESIGN: A systematic analysis of published and unpublished cross-sectional studies. METHODS: IDA rates in 1-y-old infants between 1946 and 1997 were assessed from published papers and reports. Rates for Arab infants were available from 1984. Data on routine hemoglobin tests on 1-y-old infants for Arabs and Jews separately were obtained from four health districts for the period 1987 to 1997. Analyses were done for the periods prior to and following the Public Health directives. RESULTS: The prevalence of IDA in Jewish infants declined from 68% in 1946 to 50% in 1985 at an average annual rate of -1.43%. Following the iron supplementation directives, the average annual rate of decline increased to -4.0% and reached a prevalence of about 11% in 1996. IDA rates in Arab infants declined by an annual average of -3.7%, and were consistently almost twice as high as for Jewish infants. CONCLUSIONS: Despite the contribution of the iron supplementation program to the reduction in TDA, the persistently high rates indicate inadequate iron content in the diet. This emphasizes the important role of a national food fortification program, using staple foods commonly consumed.

Anemia, Iron-Deficiency↗
PubMed2001

Thalamocortical synaptic connections: efficacy, modulation, inhibition and plasticity.

The thalamic input to the neocortex is communicated by glutamatergic synapses. The properties and organization of these synapses determine the primary level of cortical processing. Similar to intracortical synapses, both AMPA and NMDA receptors in young and mature animals mediate thalamocortical transmission. Kainate receptors participate in thalamocortical transmission during early development. The shape of thalamocortical synaptic potentials is similar to the shape of intracortical potentials. On the other hand, thalamocortical synapses have on average a higher release probability than intracortical synapses, and a much higher number of release sites per axon. As a result, the transmission of each thalamocortical axon is significantly more reliable and efficient than most intracortical axons. Thalamic axons specifically innervate a subset of inhibitory cells, to create a strong and secure feed-forward inhibitory pathway. Thalamocortical connections display many forms of synaptic plasticity in the first postnatal week, but not afterwards. The implications of the functional organization of thalamocortical synapses for neocortical processing are discussed.

Animals↗
PubMed2001

[Community health services for adolescents in Israel--challenges for the next decade].

Adolescent health issues have become an increasingly important challenge for public health in Israel. Meeting this challenge is difficult because of the special needs of this age group, inadequate training of health professionals, reimbursement policies, and the need for multisectorial cooperation. The past decade has seen a proliferation of community-based health services designed to meet the needs of adolescents. These services are of four basic types: 1) primary care clinics; 2) school health services; 3) multi-disciplinary adolescent health centers; and 4) other services, including reproductive health clinics, mental health and eating disorder units, and informal youth counseling centers. This development has taken place without systematic public health planning, including prioritization and the design of an orderly, integrative network of primary and referral services. We present national health planning goals to meet these challenges. These goals include: 1) defining the roles of each health care sector; 2) providing professional training to meet these roles; 3) facilitating the development of a rational system of community-based health services; and 4) offering a more equitable distribution of services. Implementing these goals should aid in better meeting the unique health needs Israel's adolescent population.

Adolescent↗
PubMed2000

Evidence for proportional synaptic scaling in neocortex of intact animals.

Neocortical neurons in culture can modify their global synaptic strength according to their recent activity level. This process has been termed synaptic scaling. We explored possible effects of synaptic scaling in intact animals by comparing EPSPs of two identified synaptic tracts on single cortical neurons in acute slices. We show that the amplitude and rise-time of unitary thalamocortical and intracortical EPSPs vary among different neurons, but are highly correlated on single cells. Likewise, the AMPA-to-NMDA receptor ratio in EPSPs evoked from the two tracts is correlated in single neurons, although intracortical pathways within layer 5 exhibit a significantly larger NMDA component. These findings demonstrate that, under physiological conditions, cortical neurons actively regulate their own response magnitude, regardless of the input source.

Animals↗
PubMed2000

Poison exposure in children before Passover.

BACKGROUND: Extensive cleaning of homes in Israel before Passover may result in increased exposure of children to cleaning substances. OBJECTIVES: To evaluate the potential danger of Passover cleaning to children, and to study the risk factors in order to identify areas for prevention. METHODS: All cases of poison exposure in Jewish and Arab children under the age of 15 years reported to the Israel Poison Information Center during 1990-95 (n = 5,583) were analyzed for the 6 weeks before and 6 weeks after Passover. Poison exposures in Jewish children < 15 years old were studied in seven pediatric emergency rooms for the 2 weeks before and 6 weeks after Passover (n = 123). RESULTS: The IPIC data showed a highly significant 38% increase in the average weekly poison exposure rate for the 2 weeks before Passover compared with the remaining 10 weeks. Data recorded by the pediatric emergency rooms showed a twofold increase in cleaning substance poisoning during the 2 weeks before Passover compared with the following 6 weeks. The rise in exposures to cleaning substances was observed among children from secular, religious and ultra-orthodox families. In these exposures, the substance was found in open containers in 70% of cases. CONCLUSIONS: The extensive cleaning of homes among Jewish families in preparation for Passover poses the danger to young children of cleaning substance poisoning. Increasing public awareness, closer observation of children, and keeping these substances in closed containers should increase children's safety during this annual cleaning.

Adolescent↗
PubMed1999

Efficacy of thalamocortical and intracortical synaptic connections: quanta, innervation, and reliability.

Thalamocortical (TC) synapses carry information into the neocortex, but they are far outnumbered by excitatory intracortical (IC) synapses. We measured the synaptic properties that determine the efficacy of TC and IC axons converging onto spiny neurons of layer 4 in the mouse somatosensory cortex. Quantal events from TC and IC synapses were indistinguishable. However, TC axons had, on average, about 3 times more release sites than IC axons, and the mean release probability at TC synapses was about 1.5 times higher than that at IC synapses. Differences of innervation ratio and release probability make the average TC connection several times more effective than the average IC connection, and may allow small numbers of TC axons to dominate the activity of cortical layer 4 cells during sensory inflow.

Animals↗
PubMed1999

Prenatal lead exposure in Israel: an international comparison.

BACKGROUND: Prenatal lead exposure (umbilical cord blood lead concentration > 10 (micrograms/dl) may impair cognitive development. Childhood lead poisoning is infrequent in Israel, and there are no data on lead exposure in immigrants to Israel from the former Soviet Union. OBJECTIVES: To evaluate prenatal blood lead concentrations in Israeli newborns whose mothers were born in Israel and in those whose mothers recently immigrated from Russia, and to compare data of prenatal lead exposure in Israel with those reported from other countries. METHODS: We compared the UCBLC of 35 newborns of new immigrants from Russia with a group of 35 newborns whose mothers were born in Israel. Venous BLC was also measured in 50 mothers. Data are compared with similar reports on prenatal lead exposure internationally. RESULTS: The UCBLC in all 70 newborns (mean +/- SD) was 3.53 +/- 1.6 micrograms/dl, and mothers' BLC (mean +/- SD) was 3.90 +/- 1.39 micrograms/dl. UCBLC and BLC in the 50 mother-newborn pairs correlated (r = 0.36, P < 0.01). All newborns except one had UCBLC < 8.0 micrograms/dl. There was no significant difference between UCBLC in the two groups. CONCLUSIONS: Prenatal lead exposure among the study subjects in both groups was low. In this sample the newborns of mothers born in Israel and those whose mothers recently immigrated from Russia were not found to be at risk for lead poisoning. Prenatal lead exposure in this sample was low compared to that reported from various parts of the world.

Adult↗
PubMed1998

Neuropsychological impairment from acute low-level exposure to carbon monoxide.

OBJECTIVE: To investigate the effects of acute low-level exposure to carbon monoxide on higher cognitive functions in healthy humans. DESIGN: An empirical study of the effects of low-level exposure to carbon monoxide on higher cognitive functions in young healthy volunteers and a matched nonexposed control group. SETTING: A dormitory at the Hebrew University campus in Jerusalem, Israel. PARTICIPANTS: Forty-five student volunteers who were exposed to carbon monoxide from residential kerosene stoves for 1.5 to 2.5 hours (air carbon monoxide concentrations of 17-100 ppm; mean +/- SD, 61 +/- 24 ppm) served as the experimental group and 47 nonexposed students served as the control group. MAIN OUTCOME MEASURES: A battery of neuropsychological tests was administered to each participant including digit span, the revised Wechsler Memory Scale for verbal and figural memory, Trail-Making Test parts A and B, digit symbol, block design, and the Rey Auditory Verbal Learning Test. RESULTS: Venous blood carboxyhemoglobin (Hbco) levels in participants of the study group ranged from 0.01 to 0.11 (mean +/- SD, 0.04 +/- 0.03) and correlated with air carbon monoxide concentrations (r = 0.39; P = .01). The experimental group scored significantly lower than controls on the following tests: digit span forward (P = .02), short-term (P = .008) and long-term semantic memory (P = .008), digit symbol (P = .004), block design (P = .009), recall of figural memory (P = .02), and Trail-Making part A (P = .04). No significant differences were found between the experimental and control groups in other tests. CONCLUSIONS: The lower scores on neuropsychological tests indicate dysfunctions in memory, new learning ability, attention and concentration, tracking skills, visuomotor skills, abstract thinking, and visuospatial planing and processing. These dysfunctions correspond with previous reports of carbon monoxide neurotoxic effects in patients with moderate carbon monoxide poisoning. Low-level exposure to carbon monoxide results in impairment of higher cognitive functions. Neuropsychological testing appears to be sensitive in the detection of subtle neurologic dysfunctions resulting from carbon monoxide poisoning.

Adult↗
PubMed1998

Clinical manifestations and management of scorpion envenomation.

The most venomous scorpion species are Buthotus tamulus of India, the Leiurus quinquestriatus and Androctonus crassicauda of North Africa and the Middle East, the Tityus serrulatus of Brazil, and the Centruroides suffussus of Mexico. The severity of scorpion envenomation varies with the scorpion's species, age, and size, and is much greater in children. Systemic intoxication reflects the overstimulation of the CNS, the sympathetic and parasympathetic nervous system. Severity ranges from local pain and paresthesia to fatal cardiotoxicity and encephalopathy. Symptoms include: agitation, tachycardia, vomiting, abdominal pain, salivation, diaphoresis, dehydration, muscle rigidity and twitching, tremor, seizures, coma, pupillary changes, hyperthermia, tachyarrythmias and occasionally bradyarrhythmias, hypertension, and less often hypotension, cardiac failure, and priapism in males. Laboratory abnormalities include: hyperglycemia, leucocytosis, transient elevation of cardiac and pancreatic enzymes, ischemic changes in the ECG, and evidence of cardiac dysfunction on echocardiography. The principles of management are: observation, cardiac monitoring, supportive treatment with intravenous fluids and electrolytes, and a meticulous use of cardiovascular agents: vasodilators, adrenergic antagonists, or calcium channel blockers in the hypertensive phase; and inotropic agents in the event of hypotension. Antiarrhythmics such as lidocaine, may be required. There is increasing evidence for the efficacy of specific antivenom. The advance in supportive care and antivenom efficacy has markedly improved the outcome of patients with scorpion envenomation.

Animals↗
PubMed1997

Differential regulation of neocortical synapses by neuromodulators and activity.

Synapses are continually regulated by chemical modulators and by their own activity. We tested the specificity of regulation in two excitatory pathways of the neocortex: thalamocortical (TC) synapses, which mediate specific inputs, and intracortical (IC) synapses, which mediate the recombination of cortical information. Frequency-sensitive depression was much stronger in TC synapses than in IC synapses. The two synapse types were differentially sensitive to presynaptic neuromodulators: only IC synapses were suppressed by activation of GABA(B) receptors, only TC synapses were enhanced by nicotinic acetylcholine receptors, and muscarinic acetylcholine receptors suppressed both synapse types. Modulators also differentially altered the frequency sensitivity of the synapses. Our results suggest a mechanism by which the relative strength and dynamics of input and associational pathways of neocortex are regulated during changes in behavioral state.

Animals↗