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Biomedical subjects

Y Katz

Publications and source records attributed to Y Katz.

At least 37 records · Page 2Linked to original sources
PubMed2001

Changes in effective and lethal doses of intravenous anesthetics and lidocaine when used in combination in mice.

We studied the interactions between a local anesthetic agent, lidocaine, and two general anesthetic drugs, propofol and ketamine, in mice. We used two end points: hypnosis, reflected by loss of the righting reflex, and death. The ED50 for hypnosis and the LD50 were determined for each drug separately, and a dose-response curve was prepared for each drug, using combinations of propofol-lidocane and ketamine-lidocaine at three different dose ratios. Probit and isobolographic analyses revealed supra-additive (synergistic) interactions between lidocaine and each of the other anesthetic agents regarding both the effective dose and the lethal dose. No significant difference was found between propofol and ketamine regarding the supraadditive effect.

Anesthetics, Dissociative↗
PubMed2000

Four applications of the anesthetic cut-off effect.

This article presents and analyses several cases in which the use of the cut-off effect is useful. It starts from the fact that an anesthetic effect of homologous agents is always expressible as a function of their chain lengths and that the cut-off point is a point at which the function vanishes. We then investigate four categories of results: (i) whole body effects. (ii) Cases in which the anesthetics affect the Hodgkin-Huxley parameters of a nerve. (iii) Molecular mechanisms of anesthetic action. (iv) The physical chemistry of the anesthetic process. Our discussion shows that it is possible to incorporate these apparently remote results into one framework. It also shows how to compare results that were gathered by independent measuring methods. In some instances we suggest an interpretation, in others we suggest a further gathering of experimental data. One of the deductions indicates that a weakness exists in the lipid theories of anesthesia.

Alcohols↗
PubMed2000

Fiberoptic bronchoscopy in children using the laryngeal mask airway.

We describe our experience using the laryngeal mask airway (LMA) in children to facilitate diagnostic procedures in fiberoptic bronchoscopy (FOB). Two cases of stridor, two cases of protracted pneumonia, and one case of laryngotracheomalacia were studied. Intravenous atropine (0.02 mg/kg) was given, and induction was carried out by either inhalation of a mixture of halothane-nitrous oxide-oxygen (n = 3) or IV injection of propofol (n = 2). After an adequate depth of anesthesia was obtained, a LMA was introduced. A 2.7-mm-OD flexible fiberoptic bronchoscope was introduced through the LMA and the diagnostic procedure was performed. Ventilation and oxygenation were maintained, and no serious morbidity was associated with the procedure. We found the use of the LMA to facilitate FOB to be useful, easy to perform, and safe, avoiding nasal trauma and providing a patent airway.

Bronchoscopy↗
PubMed2000

Pectoralis major muscle flap for deep sternal wound infection in neonates.

BACKGROUND: Deep sternotomy wound infections during the neonatal period, their management utilizing the pectoralis major muscle flap (PMF), and their follow-up are reported. METHODS: Seven hundred-twenty consecutive pediatric cardiac operations performed from 1995 to mid 1998 in 108 neonates and 612 infants are reviewed. Nine children (1.25%), 6 neonates and 3 infants, developed deep sternotomy wound infections and underwent PMF reconstruction. The 6 neonates are reviewed. Their follow-up includes growth and development reports, physical examination, and computerized tomographic scans of the chest. RESULTS: The incidence of sternal wound complications in our neonatal patients (5.5%, 6 of 108) was significantly higher than in the infantile group (0.5%, 3 of 612), (p = 0.0001, odds ratio = 11.94). Five neonates were treated with a unilateral, turnover PMF reconstruction. One patient was treated by a bilateral rotational PMF. All sternal wounds healed successfully, and all patients survived. In a follow-up period, ranging from 6 to 31 months (mean 16.5 months), the growth and development of all operated neonates was as expected for their age. There were no signs of chronic sternal infection in any of them. CONCLUSIONS: Early recognition of sternal wound complications should facilitate surgical treatment. Utilizing the PMF promotes rapid wound healing and preservation of life in these severely ill neonates, with minimal developmental problems.

Adolescent↗
PubMed2000

Decrease in asthma mortality rate in Israel from 1991-1995: is it related to increased use of inhaled corticosteroids?

BACKGROUND: Asthma mortality rates (AMRs) during the last several decades increased in many countries with developed medical services, including Israel. The reasons for this trend were never established. Recent data suggested that this trend is changing. OBJECTIVES: We sought to compare the AMR in Israel during 1991-1995 with that of the previous decade and to investigate a possible correlation between mortality rates and use of inhaled corticosteroids (ICSs) and beta(2)-agonists. METHODS: Statistical data on the AMR in Israel during 1981-1995 were extracted. Data were analyzed for 5- and 10-year periods (1981-1990) and compared with a 5-year period (1991-1995). Data on ICS and beta(2)-agonist sales were extracted from the marketing companies' official reports. RESULTS: The mean AMR per 100,000 population per year during 1981-1990 in the 5- to 34-year-old group was 0.393 +/- 0.055 and decreased to 0.202 +/- 0. 046 during the 1991-1995 period (P =.03). There was no significant difference between changes in mean AMR in the 35- to 64-year-old or in the 5- to 64-year-old group during the same periods (4.568 vs 4. 063 and 2.480 vs 2.133). The mean ICS unit sales rates (per 100,000 population per year) between 1982-1990 and 1991-1995 were 21.70 and 190.45, respectively (P <.05). The correlation between ICS sales and AMR was -0.631 (P =.016). Sales of beta(2)-agonists did not change significantly during the study period. CONCLUSIONS: We identified a trend of decreased AMRs in Israel during 1991-1995. The decline in AMRs paralleled the increase in ICS sales, whereas the sales of inhaled beta(2)-agonists did not change significantly. One may speculate that the decrease in AMR may be the result of better anti-inflammatory treatment, as reflected by the increased use of ICSs. The feasibility of reducing AMRs in a country such as Israel, with low AMRs to start with, by improving medical treatment is encouraging.

Administration, Inhalation↗
PubMed2000

IL-17 regulates gene expression and protein synthesis of the complement system, C3 and factor B, in skin fibroblasts.

Human IL-17 is a cytokine secreted by CD4+-activated memory T cells with the profile of effects of a Th1 cytokine. The effects of IL-17 on many cellular constituents of joints suggest that it may participate in inflammatory joint diseases. Proteins of the complement system are known to be regulated by pro- and anti-inflammatory cytokines. The purpose of this work was to study the effect of IL-17 alone and combined with tumour necrosis factor (TNF) on the expression and synthesis of factor B and C3. Fibroblasts were stimulated with the relevant cytokine or cytokines, pulse labelled with 35S-methionine, and the newly synthesized proteins were immunoprecipitated and subjected to SDS-PAGE. Gene expression was determined by Northern blot analysis. IL-17 10 ng/ml induced increases in gene expression and protein synthesis of C3, 2.25 +/- 0.26- and 2.7 +/- 0.7-fold, respectively with concomitant non-significant effects on factor B, 1.5 +/- 0.45- and 2.2 +/- 1. 2-fold, respectively. When both IL-17 and TNF were present simultaneously, the synthesis of factor B increased by 85% more than the expected additive effects of these cytokines separately, while for C3 the effect of both cytokines was 19% lower than the expected additive effect (observed/expected = 0.81). IL-4 reduced the synergistic effect by 50%. We conclude that IL-17 has a regulatory role on C3 expression and synthesis and an amplifying effect on TNF-induced factor B synthesis. Taken together with the evidence that TNF is a major cytokine involved in the inflammation of rheumatoid arthritis, it suggests that IL-17 has a proinflammatory role in the inflammation process of joints. The distinct effects of IL-4, IL-17 and TNF on the synthesis of factor B in fibroblasts suggest that factor B and the alternative pathway of the complement system may play an important role in joint inflammation.

Adolescent↗
PubMed2000

CNS penetration by noninvasive viruses following inhalational anesthetics.

The effects of inhalational anesthetics on brain penetration by the neurovirulent noninvasive West Nile virus (WN-25) were studied in mice. WN-25 injected intracerebrally causes encephalitis and kills adult mice, but when injected intraperitoneally (i.p.) it is unable to invade the brain and kill. Under stress conditions, this strain causes encephalitis and death even after i.p. inoculation. In the study described in this paper, we used two inhalational anesthetics, a single short-term exposure to 2% halothane for 10 min in oxygen, or 70% nitrous oxide (N2O) for 30 min in air. Both inhalational anesthetics induced WN-25 encephalitis and death in 33% and 20% of the tested mice, respectively. Exposure of inoculated mice to halothane for prolonged periods or for repeated exposures (two or three times) markedly increased the mortality rate (up to 75%). Exposure to 30% CO2, a known modulator of blood-brain barrier (BBB) activity, was used as a positive control (80% mortality). No death was observed in the control non-exposed injected mice. Virus levels were found to be more than 10(7) plaque-forming units (PFU)/brain in all moribund mice. Additional parameter demonstrating the "stressor-like" nature of inhalation anesthetics was the induction of a significant decrease in weight of the lymphoid organs of inoculated mice. We suggest that inhalational anesthetics induces BBB breaching with subsequent entrance of the noninvasive WN-25 virus into the brain, causing encephalitis and death.

Anesthetics, Inhalation↗
PubMed2000

Adverse reactions triggered by dental local anesthetics: a clinical survey.

One hundred and seventy-nine patients completed a questionnaire focusing on adverse reactions to dental local anesthetics as manifested by 16 signs and symptoms. Twenty-six percent of the participants reported having at least 1 adverse reaction. It was found that most of the adverse reactions occurred within the first 2 hours following the injection of local anesthetics. Pallor, palpitations, diaphoresis, and dizziness were the most common adverse reactions reported in the study. The results pointed to a significant relationship between anxiety, gender, injection technique, and procedure with a higher incidence of adverse reactions.

Adolescent↗
PubMed1999

Distinction between processing of normal and mutant complement C3 within human skin fibroblasts.

Inherited C3 deficiency may result from mutations in the C3 gene affecting transcription or translation (type I deficiency). We described a type II C3 deficiency caused by a mutation yielding an abnormal non-secreted C3. The post-translational processing of mutant and normal C3 was analyzed in fibroblasts grown from skin biopsies. Mutant C3 is located mainly in the endoplasmic reticulum (ER), whereas normal C3 is seen evenly distributed throughout the cytoplasm. Most of the mutant C3 is degraded within the cell, and only a small fraction (around 8%) is secreted after 20 h chase. Processing of C3 at 19 degrees C was reduced in normal fibroblasts but completely blocked in mutant fibroblasts. ATP depletion blocked processing of normal proC3 to C3. In contrast, the mutant proC3 was partly degraded in ATP-depleted cells, yet its complete degradation and secretion were blocked. Intracellular degradation of the mutant C3 was not inhibited by NH4Cl, thus excluding cleavage within lysosomes. These results demonstrate that the type II mutant C3 studied here is retained in the ER probably by a quality contol machinery that identifies abnormal protein folding. Consequently, it is destined to undergo a two-step intracellular degradation; an initial ATP-independent step followed by an ATP-dependent step.

Cells, Cultured↗
PubMed1999

Indoor survey of moulds and prevalence of mould atopy in Israel.

BACKGROUND: Moulds are ubiquitous indoor as well as outdoor allergens and therefore potential candidates for indoor environmental control measures. However, very few studies have been performed to examine the significance of indoor moulds in allergic diseases and the effectiveness of measures to reduce the quantity of indoor moulds has not been established. OBJECTIVE: To determine the significance and the contribution of moulds to allergic manifestations. METHODS: Prevalence of allergic rhinitis and asthma in 395 members of a rural community were examined by questionnaire and examination of medical files. The atopic status in general and allergy to moulds was determined by skin-prick tests (SPTs) to a panel of aeroallergens including Aspergillus, Penicillium, Alternaria and Cladosporium. A study of indoor mould levels was performed by placing SDA plates in 59 houses. The type of fungi and the number of colonies from each species were recorded. RESULTS: Forty-two subjects, comprising 10.9% of the study group had positive SPT to moulds, 61.9% of those were classified as symptomatic. When taking into account individuals with a borderline positive SPT to moulds, an additional 23 had positive results. Of the 65 mould-positive subjects, 48% were symptomatic and of the 13 who were allergic to moulds alone, only two had allergic symptoms. Viable moulds were recovered from all 59 houses examined. The most common isolated genus was Aspergillus, followed by Penicillium, Alternaria and Cladosporium. Aspergillus was also the most abundant mould in houses. There was no significant correlation between the abundance of moulds, positive SPT to that mould and symptomatology. CONCLUSIONS: Viable moulds are common in houses in temperate climates. Allergy to moulds itself has a low predictive value to development of allergic symptoms, but allergy to moulds in otherwise atopic subjects increases the risk of symptomatic allergic disease.

Adolescent↗
PubMed1999

Complement factor H gene mutation associated with autosomal recessive atypical hemolytic uremic syndrome.

Atypical hemolytic uremic syndrome (HUS) presents with the clinical features of hypertension, microangiopathic hemolytic anemia, and acute renal failure. Both dominant and recessive modes of inheritance have been reported. This study describes the genetic and functional analysis of a large Bedouin kindred with autosomal recessive HUS. The kindred consists of several related nuclear families in which all parent unions of affected children are consanguineous. A previous report demonstrated that a dominant form of HUS maps to chromosome 1q and that complement factor H (CFH), a regulatory component of the complement system, lies within the region and is involved in the dominant disorder. Early-onset and persistent hypocomplementemia in this Bedouin kindred prompted us to evaluate the CFH gene. Linkage analysis was performed, demonstrating linkage between the disorder and the markers near the CFH gene. Mutation analysis of the CFH coding region revealed a single missense mutation. Functional analyses demonstrate that the mutant CFH is properly expressed and synthesized but that it is not transported normally from the cell. This is the first study reporting that a recessive, atypical, early-onset, and relapsing HUS is associated with the CFH protein and that a CFH mutation affects intracellular trafficking and secretion.

Age of Onset↗
PubMed1999

Midazolam/ketamine sedative combination compared with fentanyl/propofol/isoflurane anaesthesia for oocyte retrieval.

Assisted reproduction may be associated with repeated occasions of surgical intervention. Propofol, which is frequently used for induction of anaesthesia in such procedures, has been suspected of damaging oocytes. We compared in a randomized prospective design the use of general anaesthesia with fentanyl 0.017 mg/kg, propofol 2.5 mg/kg and isoflurane to that of sedation with midazolam 0.06 mg/kg and ketamine 0.75 mg/kg for transvaginal oocyte retrieval in 50 patients with no premedication. Overall, patient satisfaction was not different between the groups. Sedated patients were more arousable than anaesthetized patients during the procedure and experienced less postoperative abdominal pain at 30 min. Despite some movement in response to pain, oocyte retrieval was conveniently feasible in all sedated patients, of which none required a switch to general anaesthesia. A comparable number of oocytes was retrieved per cycle, 10.8 (+/-7.8) versus 9.6 (+/-10.9) with sedation and anaesthesia respectively. No patient recalled any pain sensation during the procedure. The rate of embryo transfers and pregnancies were not different between the two groups. We conclude that the sedative combination of midazolam and ketamine for oocyte retrieval may serve as an alternative for general anaesthesia.

Adult↗
PubMed1998

Hypocomplementemic autosomal recessive hemolytic uremic syndrome with decreased factor H.

We describe the clinical course, complement components, and pathological findings of 10 infants with autosomal recessive hemolytic uremic syndrome (HUS). All patients were members of one extended highly inbred Bedouin kindred. The median age of presentation was 2 weeks (range 1-20 weeks). Eight patients died, 2 patients are alive, on dialysis. Renal biopsies revealed thrombotic microangiopathy with a predominant early arteriolar involvement and subsequent development of ischemic glomerular changes. Immunofluorescence was positive for C3 in glomeruli. All patients had low complement components levels during and between relapses, and in some this was evident soon after birth and prior to the onset of symptoms. This deficiency could not be normalized by repeated plasma transfusions. Biosynthetic labelling of patients' fibroblasts demonstrated normal rates of C3 protein synthesis. Serum factor H levels were greatly decreased or absent in 4 patients tested and moderately decreased in 15 of 23 healthy unaffected siblings and patients. This defect may cause complement activation and consumption, possibly at the endothelial cell level.

Arabs↗