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Biomedical subjects

A Zaritsky

Publications and source records attributed to A Zaritsky.

At least 55 records · Page 3Linked to original sources
PubMed1997

Extended screening by PCR for seven cry-group genes from field-collected strains of Bacillus thuringiensis.

An extended multiplex PCR method was established to rapidly identify and classify Bacillus thuringiensis strains containing cry (crystal protein) genes toxic to species of Lepidoptera, Coleoptera, and Diptera. The technique enriches current strategies and simplifies the initial stages of large-scale screening of cry genes by pinpointing isolates that contain specific genes or unique combinations of interest with potential insecticidal activities, thus facilitating subsequent toxicity assays. Five pairs of universal primers were designed to probe the highly conserved sequences and classify most (34 of about 60) genes known in the following groups: 20 cry1, 3 cry2, 4 cry3, 2 cry4, 2 cry7, and 3 cry8 genes. The DNA of each positive strain was probed with a set of specific primers designed for 20 of these genes and for cry11A. Twenty-two distinct cry-type profiles were identified from 126 field-collected B. thuringiensis strains. Several of them were found to be different from all published profiles. Some of the field-collected strains, but none of the 16 standard strains, were positive for cry2Ac. Three standard and 38 field-collected strains were positive by universal primers but negative by specific primers for all five known genes of cry7 and cry8. These field-collected strains seem to contain a new gene or genes that seem promising for biological control of insects and management of resistance.

Animals↗
PubMed1997

Mosquito larvicidal activity of transgenic Anabaena strain PCC 7120 expressing combinations of genes from Bacillus thuringiensis subsp. israelensis.

Various combinations of the genes cryIVA (cry4A), cryIVD (cry11A), and p20 from Bacillus thuringiensis subsp. israelensis were introduced into the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 by means of Escherichia coli-Anabaena shuttle vector pRL488p and were expressed under control of two tandem strong promoters, a cyanobacterial promoter (PpsbA) and an E. coli T7 promoter (PA1). Two of the clones carrying cryIVA plus cryIVD, one with p20 and one without p20, displayed toxicity against third-instar larvae of Aedes aegypti at levels greater than any level previously reported for transgenic cyanobacteria.

Aedes↗
PubMed1997

Gene transcription and chromosome replication in Escherichia coli.

Transcript levels of several Escherichia coli genes involved in chromosome replication and cell division were measured in dnaC2(Ts) mutants synchronized for chromosome replication by temperature shifts. Levels of transcripts from four of the genes, dam, nrdA, mukB, and seqA, were reduced at a certain stage during chromosome replication. The magnitudes of the decreases were similar to those reported previously ftsQ and ftsZ (P. Zhou and C. E. Helmstetter, J. Bacteriol. 176:6100-6106, 1994) but considerably less than those seen with dnaA, gidA, and mioC (P. W. Theisen, J. E. Grimwade, A. C. Leonard, J. A. Bogan, and C. E. Helmstetter, Mol. Microbiol. 10:575-584, 1993). The decreases in transcripts appeared to correlate with the estimated time at which the genes replicated. This same conclusion was reached in studies with synchronous cultures obtained with the baby machine in those instances in which periodicities in transcript levels were clearly evident. The transcriptional levels for two genes, minE and tus, did not fluctuate significantly, whereas the transcripts for one gene, iciA, appeared to increase transiently. The results support the idea that cell cycle timing in E. coli is not governed by timed bursts of gene expression, since the overall findings summarized in this report are generally consistent with cell cycle-dependent transient inhibitions of transcription rather than stimulations.

Bacterial Proteins↗
PubMed1996

Calf's lung surfactant extract in acute hypoxemic respiratory failure in children.

OBJECTIVE: Open-label trial of the safety and short-term efficacy of calf's lung surfactant in pediatric respiratory failure. DESIGN: Multi-institutional, uncontrolled, observational trial. SETTING: Six pediatric intensive care units of tertiary medical centers. PATIENTS: Twenty-nine children with acute hypoxemic respiratory failure, characterized by diffuse, bilateral, pulmonary infiltrates, need for ventilator support, and an oxygenation index of > or = 7. INTERVENTIONS: Up to four doses of intratracheal surfactant (80 mL/m2). MEASUREMENTS AND MAIN RESULTS: Ventilator parameters, arterial blood gases, and derived oxygenation and ventilation indices were recorded before, and at intervals after, surfactant administration. Complications and outcome measures were also noted. There was immediate improvement in oxygenation and moderation of ventilator support associated with surfactant administration in 24 of 29 patients. A modest but statistically insignificant effect was seen with subsequent doses. The only complications occurred in three patients who developed airleaks, two of which were coincident with surfactant administration. The overall mortality rate was 14%, which compares favorably with other published series. CONCLUSIONS: Administration of calf's lung surfactant appears to be safe and is associated with rapid improvement in oxygenation and moderation of ventilator support in children with acute hypoxemic respiratory failure. These results set the stage for a randomized, controlled study.

Acute Disease↗
PubMed1996

Restriction map of the 125-kilobase plasmid of Bacillus thuringiensis subsp. israelensis carrying the genes that encode delta-endotoxins active against mosquito larvae.

A large plasmid containing all delta-endotoxin genes was isolated from Bacillus thuringiensis subsp. israelensis; restricted by BamHI, EcoRI, HindIII, KpnI, PstI, SacI, and SalI; and cloned as appropriate libraries in Escherichia coli. The libraries were screened for inserts containing recognition sites for BamHI, SacI, and SalI. Each was labeled with 32P and hybridized to Southern blots of gels with fragments generated by cleaving the plasmid with several restriction endonucleases, to align at least two fragments of the relevant enzymes. All nine BamHI fragments and all eight SacI fragments were mapped in two overlapping linkage groups (with total sizes of about 76 and 56 kb, respectively). The homology observed between some fragments is apparently a consequence of the presence of transposons and repeated insertion sequences. Four delta-endotoxin genes (cryIVB-D and cytA) and two genes for regulatory polypeptides (of 19 and 20 kDa) were localized on a 21-kb stretch of the plasmid; without cytA, they are placed on a single BamHI fragment. This convergence enables subcloning of delta-endotoxin genes (excluding cryIVA, localized on the other linkage group) as an intact natural fragment.

Animals↗
PubMed1996

Raising activity of Bacillus thuringiensis var. israelensis against Anopheles stephensi larvae by encapsulation in Tetrahymena pyriformis (Hymenostomatida:Tetrahymenidae).

Toxicity of Bacillus thuringiensis var israelensis (B.t.i.) against surface-feeding mosquito larvae of Anopheles stephensi was enhanced by encapsulation in the protozoan Tetrahymena pyriformis. In the laboratory, larvae died about 8 times faster when exposed to protozoan cells filled with B.t.i. than when exposed to the same concentrations of B.t.i. alone. Best larvicidal activities were achieved with ratios of 1:200-1:500 T. pyriformis cells to B.t.i. spores. The concentration of B.t.i. needed to kill 50% of exposed populations was 4-fold lower with T. pyriformis than with B.t.i. alone in 100 ml-test cups. Toxicity enhancement is very likely a consequence of concentrating B.t.i. insecticidal crystal proteins in T. pyriformis cells and floating them to the water surface in the larval feeding zone. Reduction in the exposure time of B.t.i. to unfavorable field conditions, as a result of the decrease in larval mortality time, might improve the persistence of this biological control agent in nature.

Animals↗
PubMed1995

Recommended guidelines for uniform reporting of pediatric advanced life support: the pediatric Utstein Style. A statement for healthcare professionals from a task force of the American Academy of Pediatrics, the American Heart Association, and the European Resuscitation Council. Writing Group.

This consensus document is an attempt to provide an organized method of reporting pediatric ALS data in out-of-hospital, emergency department, and in-hospital settings. For this methodology to gain wide acceptance, the task force encourages development of a common data set for both adult and pediatric ALS interventions. In addition, every effort should be made to ensure that consistent definitions are used in all age groups. As health care changes, we will all be challenged to document the effectiveness of what we currently do and show how new interventions or methods of treatment improve outcome and/or reduce cost. Only through collaborative research will we obtain the necessary data. For these reasons, and to improve the quality of care and patient outcomes, it is the hope of the task force that clinical researchers will follow the recommendations in this document. It is recognized that further refinements of this statement will be needed; these recommendations will improve only when researchers, clinicians, and EMS personnel use them, work with them, and modify them. Suggestions, emendations, and other comments aimed at improving the reporting of pediatric resuscitation should be sent to Arno Zaritsky, MD, Eastern Virginia Medical School, Children's Hospital of the King's Daughter, Division of Critical Care Medicine, 601 Children's Lane, Norfolk, VA 23507.

Child↗
PubMed1995

Recommended guidelines for uniform reporting of pediatric advanced life support: the Pediatric Utstein Style. A statement for healthcare professionals from a task force of the American Academy of Pediatrics, the American Heart Association, and the European Resuscitation Council.

This consensus document is an attempt to provide an organized method of reporting pediatric ALS data in out-of-hospital, emergency department, and in-hospital settings. For this methodology to gain wide acceptance, the task force encourages development of a common data set for both adult and pediatric ALS interventions. In addition, every effort should be made to ensure that consistent definitions are used in all age groups. As health care changes, we will all be challenged to document the effectiveness of what we currently do and show how new interventions or methods of treatment improve outcome and/or reduce cost. Only through collaborative research will we obtain the necessary data. For these reasons, and to improve the quality of care and patient outcomes, it is the hope of the task force that clinical researchers will follow the recommendations in this document. It is recognized that further refinements of this statement will be needed; these recommendations will improve only when researchers, clinicians, and EMS personnel use them, work with them, and modify them. Suggestions, recommendations, and other comments aimed at improving the reporting of pediatric resuscitation should be sent to Arno Zaritsky, MD, Eastern Virginia Medical School, Children's Hospital of The King's Daughter, Division of Critical Care Medicine, 601 Children's Lane, Norfolk, VA 23507.

Child↗
PubMed1995

Recommended guidelines for uniform reporting of pediatric advanced life support: the pediatric Utstein style.

This statement is the product of a task force meeting held June 8, 1994, in Washington DC in conjunction with the First International Conference on Pediatric Resuscitation and a follow-up task force writing group meeting held September 18, 1994, in Chicago. Draft versions of the statement were circulated for comment to all members of the task force, the American Heart Association Subcommittee on Pediatric Resuscitation, and several outside reviewers. This statement and the International Conference on Pediatric Resuscitation were cosponsored by the American Academy of Pediatrics and the American Heart Association. The development of this statement was authorized by the American Academy of Pediatrics; the American Heart Association National Subcommittees on Pediatric Resuscitation, Basic Life Support, and Advanced Cardiac Life Support, the Committee on Emergency Cardiac Care, the Science Advisory Committee; and the European Resuscitation Council. In addition to the writing group, members of the Pediatric Utstein Task Force are Paul Anderson, M Douglas Baker, Jane Ball, Desmond Bohn, Dena Brownstein, J Michael Dean, Niranjan Kissoon, Bruce Klein, Patrick Malone, Karin McCloskey, James McCrory, P Pearl O'Rourke, Mary Patterson, Charles Schleien, James Seidel, Joseph J Tepas III, and Becky Yano.

Child↗
PubMed1995

On microbial states of growth.

It is crucial to the reproducibility of results and their proper interpretation that the conditions under which experiments are carried out be defined with rigour and consistency. In this review we attempt to clarify the differences and interrelationships among steady, balanced and exponential states of culture growth. Basic thermodynamic concepts are used to introduce the idea of steady-state growth in open, biological systems. The classical, sometimes conflicting, definitions of steady-state and balanced growth are presented, and a consistent terminology is proposed. The conditions under which a culture in balanced growth is also in exponential growth and in steady-state growth are indicated. It is pointed out that steady-state growth always implies both balanced and exponential growth, and examples in which the converse does not hold are described. More complex situations are then characterized and the terminology extended accordingly. This leads to the notion of normal growth and growth that can be synchronous or otherwise unbalanced but still reproducible, and to the condition of approximate steady state manifested by growth in batch culture and by asymmetrically dividing cells, which is analysed in some detail.

Bacteria↗
PubMed1995

Mosquito larvicidal activity of Escherichia coli with combinations of genes from Bacillus thuringiensis subsp. israelensis.

The genes cryIVA and cryIVD, encoding 134- and 72-kDa proteins, respectively, and the gene for a regulatory 20-kDa polypeptide of Bacillus thuringiensis subsp. israelensis (serovar H14) were cloned in all seven possible combinations by the Escherichia coli expression vectors pT7 and pUHE. The four combinations containing cryIVA (cryIVA alone, with cryIVD, with the 20-kDa-protein gene, and with both) displayed high levels of mosquito larvicidal activity in pUHE. The toxicity of the combination of cryIVA and cryIVD, with or without the 20-kDa-protein gene, was higher than has ever been achieved with delta-endotoxin genes in recombinant E. coli. Fifty percent lethal concentrations against third-instar Aedes aegypti larvae for these clones decreased (i.e., toxicity increased) continuously to about 3 x 10(5) cells ml-1 after 4 h of induction. Larvicidal activities, obtained after 30 min of induction, were lower for clones in pT7 and decreased for an additional 3.5 h. Induction of either cryIVD or the 20-kDa-protein gene alone resulted in no larvicidal activity in either pT7 or pUHE20. Cloned together, these genes were slightly toxic in pT7 but not in pUHE20. Five minutes of induction of this combination (cryIVD with the 20-kDa-protein gene) in pT7 yielded a maximal mortality of about 40%, which decreased rapidly and disappeared completely after 50 min. CryIVD is thus apparently degraded in E. coli and partially stabilized by the 20-kDa regulatory protein. Larvicidal activity of the combination of cryIVA and cryIVD was sevenfold higher than that of cryIVA alone, probably because of the cross-stabilization of the polypeptides or the synergism between their activities.

Animals↗
PubMed1995

Recommended guidelines for uniform reporting of pediatric advanced life support: the pediatric Utstein style. A statement for healthcare professionals from a task force of the American Academy of Pediatrics, the American Heart Association, and the European Resuscitation Council.

This consensus document is an attempt to provide an organized method of reporting pediatric ALS data in out-of-hospital, emergency department, and in-hospital settings. For this methodology to gain wide acceptance, the task force encourages development of a common data set for both adult and pediatric ALS interventions. In addition, every effort should be made to ensure that consistent definitions are used in all age groups. As health care changes, we will all be challenged to document the effectiveness of what we currently do and show how new interventions or methods of treatment improve outcome and/or reduce cost. Only through collaborative research will we obtain the necessary data. For these reasons, and to improve the quality of care and patient outcomes, it is the hope of the task force that clinical researchers will follow the recommendations in this document. It is recognized that further refinements of this statement will be needed; these recommendations will improve only when researchers, clinicians, and EMS personnel use them, work with them, and modify them. Suggestions, emendations, and other comments aimed at improving the reporting of pediatric resuscitation should be sent to Arno Zaritsky, MD, Eastern Virginia Medical School, Children's Hospital of The King's Daughter, Division of Critical Care Medicine, 601 Children's Lane, Norfolk, VA 23507.

Child↗
PubMed1994

A statewide evaluation of pediatric prehospital and hospital emergency services.

OBJECTIVE: To evaluate the extent of pediatric emergency training and the availability of pediatric equipment and patient care protocols in the prehospital and hospital settings. DESIGN: Statewide surveys developed by the North Carolina Provisional Committee on Pediatric Emergency Medical Services and by the Office of Emergency Medical Services. SETTING AND PARTICIPANTS: Surveys were mailed to all 572 prehospital Emergency Medical Service (EMS) agencies and separately to all 125 acute-care hospitals in North Carolina. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Surveys were returned by 335 (58.6%) of the prehospital providers, including all 45 paramedic and 14 advanced-intermediate provider agencies. One hundred (80%) of the acute-care hospitals returned surveys. Only 10.8% of the prehospital EMS agencies provided more than 10 hours of basic training in pediatric emergency care; 18% provided more than 5 hours of continuing education in pediatric emergencies over a 3-year period. Pediatric-specific equipment was available in many prehospital vehicles, although some deficiencies were noted. Written pediatric management, bypass, and helicopter transport protocols were absent in most prehospital programs. Paramedic programs generally were much better in all areas, although deficiencies were present. Only 14% of the responding hospitals had more than 20 pediatric beds; 13% reported seeing more than 100 patients per day in the emergency department. Deficiencies were identified in pediatric patient care protocols, triage and transport agreements, pediatric training of nurses and physicians, and equipment. Equipment deficiencies were more marked in the intensive care units than in the emergency departments. CONCLUSIONS: These survey data are inexpensive to obtain and demonstrate EMS system deficiencies. The survey information provides a baseline measurement that can lead to measurable, targeted changes in the state's EMS system for children.

Child↗
PubMed1994

Protozoan-enhanced toxicity of Bacillus thuringiensis var. israelensis delta-endotoxin against Aedes aegypti larvae.

The toxicity of Bacillus thuringiensis var. israelensis (Bti) in mosquito larvae was enhanced by encapsulation in the protozoan Tetrahymena pyriformis. Aedes aegypti larvae which fed on T. pyriformis loaded with Bti died about three times faster than when fed on the same concentrations of Bti alone due to ingestion of higher toxin concentrations, reflected by shorter death times of exposed populations. The best larvicidal activities were achieved at ratios of cell/spore numbers in the range of 1:200 to 1:500. This enhancement of mortality by preincubation with T. pyriformis was higher at low Bti concentrations or in late third-instar larvae. Ninety minutes of preincubation yielded the best enhancement effect. Toxicity enhancement is very likely a consequence of concentrating large quantities of Bti spores and crystals (containing delta-endotoxin) by T. pyriformis cells and delivering them to the larvae. Shortening larval mortality time by encapsulation in T. pyriformis should reduce the exposure time of Bti to unfavorable field conditions that inactivate its larvicidal activity. Whether this method will indeed improve Bti efficacy is still to be determined.

Aedes↗
PubMed1994

Pancreatitis in patients with organic acidemias.

STUDY OBJECTIVE: The discovery of pancreatitis in two children with methylmalonic acidemia led us to review the experience with pancreatitis in a large number of patients with organic acidemias to determine whether pancreatitis is an important complication of these disorders. DESIGN: Case series. SETTING: Pediatric metabolism services at five tertiary care centers. PATIENTS: Records of all patients with organic acidemias followed at the five institutions during the past 10 years were reviewed. Pancreatitis was recognized by symptoms and laboratory findings and confirmed by imaging studies, surgery, or autopsy. At three institutions all cases of pancreatitis in children younger than 10 years were reviewed. MEASUREMENTS AND RESULTS: Nine children with pancreatitis (seven with acute and two with chronic cases) were identified among 108 children with branched-chain organic acidemias. They ranged in age from 13 months to 9 years. Five had methylmalonic acidemia, three had isovaleric acidemia, and one had maple syrup urine disease. There were three deaths; acute hemorrhagic pancreatitis occurred in two children, and chronic pancreatitis was found at autopsy in a third. All three patients with isovaleric acidemia and pancreatitis were identified after the occurrence of pancreatitis. The survey of pancreatitis at three institutions found 57 other patients (none with an inborn error) in addition to three patients with inborn errors included in this study. CONCLUSIONS: Acute or chronic pancreatitis may complicate branched-chain organic acidemias and must be considered in the assessment of patients with these disorders who have acute clinical deterioration and vomiting, abdominal pain, encephalopathy or shock, or milder symptoms. Conversely, an inborn error of organic acid metabolism should be considered in children with pancreatitis of unknown origin.

Acute Disease↗