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Z Grossman

Publications and source records attributed to Z Grossman.

At least 19 recordsLinked to original sources
PubMed2006

Bayesian network analysis of resistance pathways against HIV-1 protease inhibitors.

Interpretation of Human Immunodeficiency Virus 1 (HIV-1) genotypic drug resistance is still a major challenge in the follow-up of antiviral therapy in infected patients. Because of the high degree of HIV-1 natural variation, complex interactions and stochastic behaviour of evolution, the role of resistance mutations is in many cases not well understood. Using Bayesian network learning of HIV-1 sequence data from diverse subtypes (A, B, C, F and G), we could determine the specific role of many resistance mutations against the protease inhibitors (PIs) nelfinavir (NFV), indinavir (IDV), and saquinavir (SQV). Such networks visualize relationships between treatment, selection of resistance mutations and presence of polymorphisms in a graphical way. The analysis identified 30N, 88S, and 90M for nelfinavir, 90M for saquinavir, and 82A/T and 46I/L for indinavir as most probable major resistance mutations. Moreover we found striking similarities for the role of many mutations against all of these drugs. For example, for all three inhibitors, we found that the novel mutation 89I was minor and associated with mutations at positions 90 and 71. Bayesian network learning provides an autonomous method to gain insight in the role of resistance mutations and the influence of HIV-1 natural variation. We successfully applied the method to three protease inhibitors. The analysis shows differences with current knowledge especially concerning resistance development in several non-B subtypes.

Bayes Theorem↗
PubMed2006

Analysis of HIV-1 pol sequences using Bayesian Networks: implications for drug resistance.

Human Immunodeficiency Virus-1 (HIV-1) antiviral resistance is a major cause of antiviral therapy failure and compromises future treatment options. As a consequence, resistance testing is the standard of care. Because of the high degree of HIV-1 natural variation and complex interactions, the role of resistance mutations is in many cases insufficiently understood. We applied a probabilistic model, Bayesian networks, to analyze direct influences between protein residues and exposure to treatment in clinical HIV-1 protease sequences from diverse subtypes. We can determine the specific role of many resistance mutations against the protease inhibitor nelfinavir, and determine relationships between resistance mutations and polymorphisms. We can show for example that in addition to the well-known major mutations 90M and 30N for nelfinavir resistance, 88S should not be treated as 88D but instead considered as a major mutation and explain the subtype-dependent prevalence of the 30N resistance pathway.

Amino Acid Sequence↗
PubMed2005

How much acetaminophen do paediatricians prescribe? A survey among Israeli paediatricians.

OBJECTIVE: To describe the current practice of Israeli paediatricians regarding acetaminophen dosing. METHODS: A cross-sectional survey among 200 paediatricians. The paediatricians were questioned of the recommended dose of acetaminophen, and whether they give prescriptions for acetaminophen and instruct their patients how to use it. RESULTS: The response rate was 36%. When asked on the recommended dose of acetaminophen, 30 (42%) physicians gave doses different from the dose recommended by the Israeli formulary. Thirty (42%) of the paediatricians answered that they usually or always give prescriptions for antipyretics. CONCLUSIONS: A large percentage of Israeli paediatricians do not provide parents proper instructions regarding the correct dosing of acetaminophen.

Acetaminophen↗
PubMed2004

Drug-resistant HIV infection among drug-naive patients in Israel.

BACKGROUND: In Israel, <0.06% of the general population is infected with human immunodeficiency virus (HIV), with a much higher prevalence among specific groups. These groups are distinguished demographically by risk behavior category and by virus subtype. We investigated transmission of drug resistance within groups to assess the impact of these factors. METHODS: Plasma samples from >15% of all patients with new diagnoses of HIV infection were randomly collected between June 1999 and June 2003. Sequences from 176 drug-naive patients included 20 of subtype A, 20 of subtype AE, 2 of subtype AC, 29 of subtype B, 100 of subtype C, and 5 of subtype F. RESULTS: Major drug resistance mutations (protease: L90M; reverse transcriptase: M41L, K103N, V106M, M184V, Y181S, G190A, L210W, T215Y/F, and K219R) were detected in 1 subject with A subtype, 3 with subtype B, and 9 with subtype C. In addition, 1 subject with A subtypes, 2 with subtype B, and 10 with subtype C had secondary mutations (protease: M46I; reverse transcriptase: A98G, K101Q, and V108I). Only 1 patient had mutations associated with >1 class of drugs. Among subjects who contracted HIV infection in Israel, 16 of 56 (1 of 7 with subtypes A or AE, 4 of 17 with subtype B, and 11 of 32 with subtype C; P=.7-1.0) carried resistant virus--a significantly higher proportion (P<.001) than in subjects infected in other countries (10 of 120 infected). CONCLUSIONS: Drug-resistant virus was detected in 14.8% of patients with new diagnoses of HIV infection but in 28.6% of patients known to have been infected in Israel. The implications include a need for pretreatment resistance testing and for better programs aimed at prevention of transmission, directed particularly at patients. We did not find significant differences in transmission of resistant virus between those infected with subtypes B and C, despite the different demographic background. A conclusive analysis and interpretation should await a more extensive study.

Adult↗
PubMed2004

Comparison of efficiency and preference of metal and plastic spacers in preschool children.

BACKGROUND: The metal NebuChamber valved holding chamber (VHC) has gained wide acceptance among children with asthma. Due to its nonelectrostatic properties and larger volume, the 250-mL, metal NebuChamber delivers a greater mass of aerosol to a filter at the mouth compared with the commonly used 150-mL polypropylene AeroChamber VHC. Such in vitro results have been used to suggest that this may provide increased efficacy with the NebuChamber. No comparative efficacy data exist for preschool children with asthma. OBJECTIVE: To compare efficiency and preference of metal and plastic spacers in preschool children. METHODS: Children with mild-to-moderate persistent asthma received 200 microg of budesonide twice daily by NebuChamber or AeroChamber, both with the mask provided in a randomized, 2-month, crossover trial. Symptom diary cards, beta-agonist use, and preference by children and parents were compared. RESULTS: Thirty children (mean +/- SD age, 4.3 +/- 0.3 years) completed the study. There was no difference between the AeroChamber and NebuChamber in clinical efficacy outcomes. There was no difference between the AeroChamber and NebuChamber in parents' view of ease of use, design, acceptability by the children, and overall satisfaction. CONCLUSIONS: Despite a greater total dose delivered to the mouth, the NebuChamber appears no more effective than the AeroChamber and it is not preferred by patients or parents. More parents chose to continue to use the NebuChamber after the study.

Administration, Inhalation↗
PubMed2004

Epidemiology of adult and adolescent HIV infection in Israel: a country of immigration.

In Israel, the caseload and main modes of transmission have changed dramatically since 1991 after mass immigration from countries with generalized HIV epidemics. The previous annual average (of 60 new cases) has almost quadrupled, and 68% are among heterosexuals (compared with 11.6% before). We verified all HIV/AIDS cases ever documented, redefined (according to UNAIDS/WHO definitions) and analysed those aged 13+. Between 1980-2000, HIV and AIDS were diagnosed, respectively, in 2204 and 682 adults and adolescents (cumulative HIV infection rate = 61/100 000). Of these, 65.2% are male (mean age 35.0 years old; SD = 11.0), 31.5% female (mean age 31.4 years old; SD = 10.5) (and 3.3%, sex unknown). The main modes of HIV transmission were heterosexual (45%), MSM (16.9%) and IDUs (11.5%). Prevention measures must be strengthened, if the currently low-level of HIV epidemic among the Israeli general population is to be sustained.

Adolescent↗
PubMed2003

Safety of inhaled corticosteroids delivered by plastic and metal spacers.

BACKGROUND: Because of its non-electrostatic properties the metal Nebuchamber (NC) valved holding chamber (VHC) delivers a greater mass of aerosol to the mouth than the polypropylene Aerochamber (AC) VHC. Delivery of more aerosol to the lungs may also increase systemic absorption of inhaled corticosteroids (ICS) and hypothalamo-pituitary-adrenal (HPA) suppression. METHODS: Thirty children (mean 4.3 (SD 0.3) years) received 200 micro g budesonide twice daily by NC or AC, both with the mask provided, in a randomised, two month crossover trial. Twenty four hour urinary free cortisol (UFC) was determined as a measure of HPA suppression. RESULTS: UFC decreased from 42.3 (7.8) nmol UFC/nmol creatinine control to 26.2 (2.4) (p = 0.06 v control) after AC, and to 24.5 (2.5) (p = 0.04 v control) after NC (p = 0.4 AC v NC). CONCLUSIONS: Despite a greater total dose delivered to the mouth, NC is not associated with greater HPA suppression when using 400 micro g/day budesonide under real life conditions in young children.

Anti-Inflammatory Agents↗
PubMed2002

Radioimmunoscintigraphy (RIS) with bectumomab (Tc99m labeled IMMU-LL2, Lymphoscan) in the assessment of recurrent non-Hodgkin's lymphoma (NHL).

UNLABELLED: The efficacy of a Tc99m-labeled anti-lymphoma antibody fragment, bectumomab [LymphoScan], was retrospectively examined in the staging of recurrent or newly diagnosed non-Hodgkin's lymphoma (NHL) [7 patients] and to assess targeting before radioimmunotherapy (RIT) [14 patients]. Performance was graded relative to conventional imaging. Tumors included 7 low-grade, 11 intermediate-grade, and 3 high-grade histologic subtypes. Computed x-ray tomography, radiogallium imaging, FDG-PET, and bone marrow biopsy defined 117 sites. Bectumomab revealed 56% of these sites. In 4 patients bectumomab uncovered five sites not evident by conventional imaging. In addition, it uncovered one site in the brain, an area not covered in the standard work-up of asymptomatic patients. Bectumomab imaging most often failed in central abdominal and thoracic locations, and excelled in revealing disease in the head and neck. Relative to Ga67 citrate imaging, the performance of bectumomab was variable, with no clear relation to anatomic location; there was better targeting of low and intermediate grade NHL. Radiogallium out-performed bectumomab imaging in 23 sites, 19 of which were in patients with high or intermediate-grade disease. Bectumomab was superior to radiogallium at six sites, five of which involved low-grade tumor. CONCLUSION: Bectumomab shows promise as a pre-RIT probe for targeting of B-cell NHL. It excelled at defining small volume, low-grade disease. However, as a purely diagnostic agent, its performance was variable.

Antibodies, Monoclonal↗
PubMed2001

Genotypic variation of HIV-1 reverse transcriptase and protease: comparative analysis of clade C and clade B.

OBJECTIVE: To compare drug-resistant variants from untreated (naive) and treated patients infected with clade B or C virus. METHODS: Consecutive samples (165) from patients throughout Israel were analyzed. All those in the treated group were failing highly active antiretroviral therapy. RESULTS: There were 87 clade B (14 naive) and 78 clade C (20 naive) [corrected] with significant differences in the prevalence of known drug-resistance mutations between the clades: in naive patients in the protease region M36I 7% and 95% (P < 0.0001), K20R 0% and 27% (P = 0.063), A71V 18% and 0% (P = 0.063), M46I 0% and 13%, and V77I 18% and 0% (P = 0.063), respectively, and in the reverse transcriptase region A98G/S 0% and 20% (P = 0.12), respectively. Most clade C viruses also showed significant differences from clade B consensus sequence at additional protease sites: R41K 100%, H69K/Q 85%, L89M 95% and I93L 80% (P < 0.0001). There were also significant differences (P < 0.03 to < 0.0001) in treated patients in clades B and C: in the protease region L10I 40% and 12%, M36I 26% and 95%, L63P 67% and 40%, A71I 38% and 7%, G73I and V77I 18% and 0%, I84V 16% and 3%, and L90M 40% and 12%, respectively; in the reverse transcriptase M41L 41% and 17%, D67N 41% and12%, K70R 30% and 7%, T215Y 48% and 29%, K219Q 21% and 7%, and A98G/S 3% and 24%, respectively. CONCLUSION: Significantly differences between clade B and C viruses may be associated with development of differing resistance patterns during therapy and may affect drug utility in patients infected with clade C.

Adolescent↗
PubMed2001

Autoreactivity, dynamic tuning and selectivity.

The immune system adjusts its response to the context in which antigens, including self-antigens, are recognized. Recent observations support a conceptual framework for understanding how this may be achieved at the cellular and cell-population levels. At both levels, 'perturbations' elicit competition between excitation and de-excitation, resulting either in adaptation or in various responses. The responsiveness of individual cells is dynamically tuned, reflecting their recent experience. The tuning of T-cell activation thresholds by self-ligands facilitates positive selection and continuously regulates the level of autoreactivity in the periphery. Autoreactivity appears to be involved in regulation of the immune response, homeostasis, maintaining of the functional integrity of naïve and memory cells, and in other physiological functions.

Adaptation, Physiological↗
PubMed2001

West Nile fever in Israel 1999-2000: from geese to humans.

West Nile virus (WNV) caused disease outbreaks in Israel in the 1950s and the late 1970s. In 1998 an outbreak of WNV in goose farms and evidence of infection in dead migratory birds were reported. Consequently, human diagnostic services for WNV were resumed, including virus isolation, serology, and RT-PCR. Risk factors for infection were assessed by a serological survey in 1999, which revealed a seroprevalence of (a) 86% in people who had close contact with sick geese, (b) 28% in people in areas along bird migration routes, and (c) 27% in the general population. Following two fatal cases in Tel Aviv in September 1999 and one encephalitis case in the southern Eilot region, a regional serological survey was initiated there. The survey revealed two more WNV-associated acute encephalitis cases, an IgG seroprevalence of 51%, and an IgM seroprevalence of 22%. In the summer of 2000, acute cases of WN disease were identified in the central and northern parts of Israel, involving 439 people. The outbreak started in mid-August, peaked in September, and declined in October, with 29 fatal cases, primarily in the elderly. During the outbreak, diagnosis was based on IgM detection. Four virus isolates were subsequently obtained from preseroconverted frozen sera. Sequence and phylogenetic analysis of 1662 bases covering the PreM, M, and part of the E genes revealed two lineages. One lineage was closely related to a 1999 Israeli bird (gull) isolate and to a 1999 New York bird (flamingo) isolate, and the other lineage was closely related to a 1997 Romanian mosquito isolate and to a 1999 Russian human brain isolate.

Adult↗
PubMed2000

Self-tolerance: context dependent tuning of T cell antigen recognition.

Physiological messages to cells are encoded in the magnitude, and in the time- and space-contingencies, of sets of stimuli. In particular, individual T cells continuously integrate antigenic and other signals and respond differentially to the rate of change in the level of stimulation, translated intracellularly into 'metabolic perturbations'. The organization of the immune response at the cell-population level in space and time is also conductive to discriminating the magnitude of 'system perturbations'. In this way, the immune system was 'designed' to respond in a characteristic explosive way mainly to episodes of infection and not to the continuous presence of self-antigens. T cells are selected to be moderately autoreactive, and the degree of autoreactivity that they express is continuously controlled through activation-threshold tuning. Their level of autoreactivity is maintained in a range that facilitates survival and self-renewal and is probably used in performing some immunoregulatory functions and possibly other physiological functions. Autoreactivity and outward-directed immunity are regulated simultaneously and interactively through the interplay of selection, tuning, controlled activation and feedback.

Antigens↗
PubMed2000

Changing epidemiology of dengue fever in travelers to Thailand.

A study was conducted to evaluate the incidence and seasonal pattern of dengue fever occurring among Israeli travelers to Southeast Asia. The illness was diagnosed by Israeli physicians stationed abroad and by serological methods carried out in Israel. Between 1994 and 1998 dengue fever was confirmed in 103 travelers, 80 of whom were diagnosed in Israel. A sharp increase in the incidence was noted in 1998 as compared with the previous 4 years. The attack rate during 1998 in a defined group of travelers was 3.4/1,000 and reached a peak of 5/1,000 during the dry season of 1998.

Dengue↗
PubMed2000

Evaluation of ELISA-based sero-diagnosis of dengue fever in travelers.

Diagnosis of dengue virus infection in travelers is often based on commercially available ELISA-based serological assays and not on the more difficult and costly procedures of Hemagglutination inhibition (HI), virus isolation or RT-PCR. These standard assays are not quantitative and are designed to diagnose primary and secondary dengue virus infections by testing for IgG and IgM antibodies. However, cross reactivity between various flaviviruses and the fact that most travelers today are prevaccinated against Japanese encelphalitis (JE) and yellow fever (YF) create a potential problem in such diagnosis. Our study was aimed at measuring the extent of false positive diagnosis in prevaccinated travelers which we have assessed by testing for dengue IgG and IgM antibodies in a group of prevaccinated healthy travelers using the PanBio indirect IgG ELISA and IgM capture ELISA kits. The IgM test was negative in all healthy vaccinees, thus, being highly specific. However, the kit had a disadvantage, which was recognized in other travelers clinically ill with dengue fever (DF), in which the IgM response was detected only 4-8 days after onset of the clinical symptoms. The IgG test yielded 11-17 and 15-44% positives in healthy travelers vaccinated against JE and YF, respectively. We conclude that the specificity of the IgG-ELISA assay in prevaccinated travelers is much lower than in unvaccinated populations. Thus, an IgG-positive results in a vaccinated traveler and IgM negative result during the 1st week of the illness period, are both inconclusive.

Adult↗
PubMed2000

Resolution of the pathways of poliovirus type 1 transmission during an outbreak.

An outbreak of poliomyelitis with 20 cases occurred in Israel, Gaza, and the West Bank from October 1987 to October 1988. The wild type 1 poliovirus associated with the outbreak was most closely related to viruses found in the Nile Delta. The epidemiologic links among patients involved in the outbreak and patients with community-acquired infections during the outbreak were inferred from the evolutionary relationships among isolates of the outbreak virus. Complete VP1 sequences (906 nucleotides) were determined for 12 clinical and 4 sewage isolates. A total of 58 nucleotide differences were found among the 16 isolates; 74% of all substitutions were synonymous third-position transitions. An evolutionary tree, representing both the pathways of VP1 sequence evolution and the inferred chains of virus transmission during the outbreak, was constructed under the assumption that each substitution had occurred only once. The combined epidemiologic and molecular data suggest that a single founder strain was introduced into Israel from the vicinity of Gaza in the fall of 1987. Poliovirus circulation was apparently localized to southern communities during the winter and spread north by the following summer into the Hadera subdistrict of Israel, where it radiated via multiple chains of transmission into other communities in northern Israel and the West Bank. The close sequence matches (>99%) between clinical and sewage isolates from the same communities confirm the utility of environmental sampling as a tool for monitoring wild poliovirus circulation.

Base Sequence↗
PubMed2000

Evaluation of the approach of primary care physicians to the management of streptococcal pharyngotonsillitis. IPROS Network.

BACKGROUND: Streptococcal pharyngotonsillitis remains a common illness in children and can lead to serious complications if left untreated. OBJECTIVE: To evaluate the diagnostic and management approach of a sample of primary care physicians in the largest sick fund in Israel to streptococcal pharyngotonsillitis in children. METHODS: A questionnaire was mailed to all physicians who treat children and are employed by the General Health Services (Kupat Holim Klalit) in the Jerusalem District. The questionnaire included data on demographics, practice type and size, and availability of throat culture and rapid strep test; as well as a description of three hypothetical cases followed by questions relating to their diagnosis and treatment. RESULTS: Of the 188 eligible physicians, 118 (62.5%) responded, including 65 of 89 pediatricians (73%) and 53 of 99 family and general practitioners (53.5%). Fifty-six physicians (47.4%) had more than 18 years experience, and 82 (70%) completed specialization in Israel. Mean practice size was 950 patients. Fifty-three physicians (43%) worked in Kupat Holim community clinics, 25 (21%) worked independently in private clinics, and 40 (34%) did both. A total of 91 (77%) had access to laboratory facilities for daily throat culture. The time it took for the results to arrive was 48 to 72 hours. For the three clinical scenarios, 90% of the physicians accurately evaluated case A, a 1-year-old with viral pharyngotonsillitis, and 100 (85%) correctly diagnosed case C, a 7-year-old with streptococcal infection. As expected, opinions were divided on case B, a 3-year-old child with uncertain diagnosis. Accordingly, 75 (65.3%) physicians did not recommend treatment for case A, compared to 109 (92.5%) for case C. For case B, 22 (19%) said they would always treat, 43 (36%) would sometimes treat, and 35 (30%) would await the result of the throat culture. For 104 (88%) physicians the antibiotic of choice for case C was penicillin, while only 9 (7.5%) chose amoxicillin. However, the recommended dosage regimens varied from 250 to 500 mg per dose, and from two to four doses daily. For case C, 110 physicians (93%) chose a 10 day duration of treatment. CONCLUSIONS: The primary care physicians in the sample (pediatricians, general practitioners and family physicians) accurately diagnosed viral and streptococcal pharyngotonsillitis. However, there was a lack of uniformity regarding its management in general, and the dosage regimen for penicillin in particular.

Child↗
PubMed1999

[Pediatric research in an office-setting network--a new dimension in pediatric research in Israel].

Pediatric care in the community is gradually replacing traditional care in hospitals. Despite that, research activity in the community setting is minimal due to objective difficulties. These are mainly constraints of time, office work and lack of research-supporting logistics. In the past decade, throughout the world, primary physicians interested in research have grouped together and formed research networks. The aim of such networks is to support and promote research in the community. An Israel Pediatric Research in Office-Setting network (IPROS) was established 2 years ago by the Israel Ambulatory Pediatric Association (IAPA). Today, there are over 140 pediatricians listed in IPROS, representing the heterogeneous composition of pediatricians in Israel. The network's policy is defined by a joint steering committee. The committee is composed of IAPA representatives, senior network members and Schneider Hospital senior investigators. The research subjects are diverse, and represent common practical issues. Effective intra-net communication is vital to the existence of the network, and is accomplished by 3 modalities: 1) semiannual updates by mail, 2) e-mail, using an electronic mailing list to facilitate connection between members, 3) semi-annual meetings. Research budgets are derived from public sources like the Ministry of Health and IAPA, and private sources such as pharmaceutical companies. The administration of the network is supported by Schneider Children's Medical Center, and financed by IAPA.

Ambulatory Care↗