Search PubMed⌕ Search

Biomedical subjects

D Cohen

Publications and source records attributed to D Cohen.

At least 325 records · Page 18Linked to original sources
PubMed1994

Identification of alpha 2 adrenergic receptor gene expression in sympathetic neurones using polymerase chain reaction and in situ hybridization.

alpha 2 Adrenergic receptors are involved in mediating pre- and postsynaptic responses in the sympathetic nervous system. In this study, the expression of alpha 2 genes was examined by the amplification of mRNA, extracted from adult rat superior cervical ganglion through reverse transcription and subsequent amplification of appropriate target sequence using polymerase chain reaction and sequence specific oligonucleotide primers for the three alpha 2 receptor genes. Results from these studies have shown that the major alpha 2 adrenergic mRNA transcript was the one that encodes the alpha 2A receptor. Nucleotide sequence of the 312 base-pair (bp) alpha 2A cDNA was homologous to the RG20 adrenergic receptor, the rat homologue of the human alpha 2A receptor. The 312 bp alpha 2A cDNA was used as a probe in Northern blot analysis of the mRNA from superior cervical ganglion and brain. A 3.9 kb mRNA transcript was present in these extracts. To confirm that the alpha 2A gene expression was in the sympathetic neurones we have used the 312 bp alpha 2A cDNA, biotinylated, as a probe for in situ hybridization studies and have demonstrated that the alpha 2A mRNA was found only in the cell bodies of sympathetic neurones.

Animals↗
PubMed1994

Safety and immunogenicity of the oral E. coli K12-S. flexneri 2a vaccine (EcSf2a-2) among Israeli soldiers.

A double-blind placebo-controlled study was carried out on the safety and immunogenicity of the oral Shigella flexneri (EcSf2a-2) vaccine among Israeli soldiers. Sixty volunteers received the vaccine and 59 received placebo. Fifty-three were given the full vaccine regimen (four doses). Doses ranged between 4.1 x 10(8) and 1.1 x 10(9) c.f.u. Visits to the unit clinic for mild gastrointestinal symptoms were common after the first dose in vaccinees (13%) as compared with placebo recipients (5%), but the difference was not significant, p = 0.12. Similarly, there was no difference between the groups for either gastrointestinal or non-gastrointestinal complaints reported by questionnaire. The vaccine strain was excreted by 69% and 67% of the vaccinees one day after receiving the second and the fourth doses, respectively. As judged by antibiotic susceptibility, phage typing and restriction fragment length polymorphism (RFLP), the vaccine strain emerged as genetically stable after replication in human gut and shedding. There was neither bacteriological nor serological evidence of transmission of the vaccine from vaccinees to placebo recipients. Eighteen of 26 (69.2%) and 11 of 30 (36.7%) vaccinees had significant IgA secreting cell responses 7 and 21 days after the first dose, respectively. Significant IgA or IgG serum antibody response to S. flexneri 2a LPS was detected in 30% of the vaccinees. These results support further evaluation of EcSf2a-2 vaccine protective efficacy in field studies.

Administration, Oral↗
PubMed1994

Four-year follow-up of the immune status of young adults given a single booster dose of trivalent oral poliovaccine.

In 1988 an outbreak of type 1 paralytic poliomyelitis occurred in Israel. Almost the entire population in the age group 0-40 years received a single dose of trivalent oral polio vaccine. We examined the serological responses to the vaccine at 2 weeks and 4 years later, in a group of 17 vaccines. Geometric mean antibody titres (GMTs) against both the type 1 epidemic and Mahoney strains had declined by about 50% from the levels found at 2 weeks after vaccination. However, they were still more than five times higher than the prevaccination levels. All vaccines had neutralizing antibody titres against both the type 1 strains of at least 1:64, well above the 1:8 titre regarded as protective. The GMTs against the type 2 and 3 strains declined to about one-third of the 2-week postvaccination levels but were also well above protective levels. These findings indicate that antibody titres against both the Mahoney and epidemic type 1 strains remained at very adequate levels over a period of at least 4 years. Thus the immunity resulting from a single booster dose of oral poliovaccine in young adults is likely to be long-lasting, a finding of particular importance for travellers on extended visits to endemic areas.

Adolescent↗
PubMed1994

Urinary free cortisol values in children under stress.

Children with adrenocortical insufficiency are commonly instructed to increase their baseline glucocorticoid replacement doses by three to five times during periods of stress such as surgery or febrille illness. We conducted this to determine whether these recommendations reflect the actual change in urinary free cortisol (UFC) output during stress. The 24-hour UFC excretion was determined in 78 children who were admitted to a general pediatric department or intensive care unit with temperature > 38.7 degrees C, after major surgery, or during status epilepticus; we reevaluated 43 of the patients 2 weeks after recovery. In addition, the 24-hour UFC levels were determined in 127 healthy children aged 1.8 to 17 years. The UFC level positively correlated with age (r = 0.254; p < 0.001). The amount of UFC per gram of creatinine was inversely correlated with age (r = 0.255; p < 0.001). The amount of UFC per surface area was independent of age. The mean change in the level of UFC per square meter surface area was highest among children who had cardiothoracic surgery and those with multiple trauma. The increase in UFC level during bacterial infection was significantly greater than that during viral infection. The current recommendation to increase the dose to three to five times the baseline glucocorticoid dose during times of stress may underestimate the changes in UFC found in some patients with major surgery, trauma, or certain serious bacterial infections. Production rate studies are needed to prove this point.

Abdomen, Acute↗
PubMed1994

A primary care checklist for effective family management.

After briefly reviewing the risks of caregiving, this article describes guidelines for practical clinical management of patients and family members in primary care settings. Much can be done to enhance the health and quality of life of patients with dementia and their families. Patients need to know that their physician is a resource who is there for them, who will listen to the story of their illness, and who knows where to send them for more information and help.

Aged↗
PubMed1994

Genetic associations with human longevity at the APOE and ACE loci.

In an effort to dissect the genetic components of longevity, we have undertaken case-control studies of populations of centenarians (n = 338) and adults aged 20-70 years at several polymorphic candidate gene loci. Here we report results on two genes, chosen for their impact on cardiovascular risk, encoding apolipoprotein E (ApoE), angiotensin-converting enzyme (ACE). We find that the epsilon 4 allele of APOE, which promotes premature atherosclerosis, is significantly less frequent in centenarians than in controls (p < 0.001), while the frequency of the epsilon 2 allele, associated previously with type III and IV hyperlipidemia, is significantly increased (p < 0.01). A variant of ACE which predisposes to coronary heart disease is surprisingly more frequent in centenarians, with a significant increase of the homozygous genotype (p < 0.01). These associations provide examples of genetic influences on differential survival and may point to pleiotropic age-dependent effects on longevity.

Adult↗
PubMed1994

Identification of two nuclear protein binding sites and their role in the regulation of the murine multidrug resistance mdr1a promoter.

Multidrug resistance genes (mdr) that encode P-glycoproteins (P-gp) are transcriptionally regulated in normal tissues and in some multidrug-resistant (MDR) cells. Several lines of evidence suggest that regulation of P-gp overexpression at the transcriptional level is also important in human tumors. In murine MDR cells, mdr1a and/or mdr1b genes are overexpressed and P-gp isoforms are overproduced. To identify the mdr1a promoter regions that are required for transcription, the promoter has been linked to the chloramphenicol acetyltransferase (CAT) gene in transient expression vectors. 5'-Deletions of the promoter sequences have demonstrated that the region between -155 to +89 bp is crucial for basal activity of the mdr1a gene. DNase I footprinting, methylation interference, and gel retardation assays identified two nuclear protein binding sites within these sequences. One of the nuclear protein binding sites contains an 11-bp DNA sequence that interacts with nuclear protein(s) and is conserved in the promoters of the murine mdr1a and mdr1b, hamster pgp1, and human MDR1 genes. The conserved SP1 site (5'-GGGCGGG-3') that is present further downstream was shown to interact with its nuclear factor. These observations suggest that at least part of mdr gene transcriptional regulation is mediated by conserved mdr cis-regulatory elements and common nuclear factors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Construction of a YAC contig and a STS map spanning at least seven megabasepairs in chromosome 5q34-35.

We have constructed a YAC contig containing 54 clones and a minimum of 7 Mbp of human DNA, that maps to bands q34-35 on chromosome 5. The contig was nucleated using FISH mapped cosmid clones shown to flank the t(2;5)(p23;q35) translocation breakpoint in a CD30-positive large cell lymphoma cell line. Thirty of the 54 YAC clones are non-chimeric and six span the translocation breakpoint, as determined by FISH analysis. A total of 28 YAC clone end fragments, 14 non-polymorphic YAC end STS probes and 13 polymorphic microsatellite STS markers have been used to order clones within the contig. The most distal genetic markers (D5S498 and D5S619) are separated by 15 cM based on multipoint linkage analysis. This map of overlapping clones and the set of densely spaced physical markers will promote our understanding of the 5q34-35 region and its associated genes.

Base Composition↗
PubMed1994

Sex differences in the humoral antibody response to live measles vaccine in young adults.

BACKGROUND: Following vaccination of children using high-titre live measles vaccine, excess non-specific mortality was reported, particularly among females. Since vaccination with live measles virus results in a temporary depression of the immune response to other antigens, the female predominance in subsequent non-measles mortality may be due to sex differences in response to live measles vaccines. METHODS: In this study, the immunogenicity of standard titre live Schwarz strain measles vaccine was examined 2 and 4 weeks post-vaccination in 223 males and 66 female aged 18-20 years in Israel in 1991. RESULTS: Females had higher post-vaccination geometric mean titre (GMT) at all levels of pre-vaccination titres at both 2 and 4 weeks. Furthermore, after controlling for differences in pre-vaccination titres, overall the post-vaccination GMT for females was about 50% higher than for males (P < 0.001). CONCLUSIONS: These findings indicate that females exhibit a stronger humoral immune response to measles vaccine. Possible sex differences in immunosuppression following measles vaccination should be explored.

Adolescent↗
PubMed1994

Epidemiology of acute diarrheal diseases in children in a high standard of living rural settlement in Israel.

Epidemiologic patterns of acute diarrheal diseases in a high standard of living communal settlement, situated in a region endemic for enteric diseases, were evaluated by a historical prospective study of 284 children (12,064 child months) from August, 1988, through July, 1992. Three hundred eighty-three episodes of acute diarrhea were identified, yielding a rate of 0.38 episode per 12 child months. One hundred and children (35.6%) were reported to have 1 to 4 diarrheal episodes and 29 (10.2%) children had 5 or more diarrheal episodes during the follow-up period. The mean number of episodes of acute diarrhea per 12 child months in children ages 0 to 2 years was 2.28, in 2- to 6-year-olds 0.44, in 6- to 13-year-olds 0.12 and in 13- to 18-year-olds 0.03 (P < 0.001). Children less than 12 months of age had a lower incidence of acute diarrheal diseases during the months they were being breast-fed than children that were fed with formula during the same period (1.22 vs. 3.06 episodes per 12 child months, respectively; P < 0.001). Enteropathogens were isolated in 40% of diarrheal episodes in which stool cultures were obtained. The identification rates of the various enteropathogens were: diarrheagenic Escherichia coli, 11%; Shigella spp., 10%; Giardia lamblia, 10%; Salmonella spp., 4%; Staphylococcus aureus, 3%; Campylobacter jejuni, 1%. Potential interventions against acute diarrhea in this set up of a high standard of living rural community are education of caretakers and parents on hygienic practices that can prevent transmission of pathogens among the young children and encouraging mothers to breast-feed their children.

Acute Disease↗
PubMed1994

Enhancement of anti-Shigella lipopolysaccharide (LPS) response by addition of the cholera toxin B subunit to oral and intranasal proteosome-Shigella flexneri 2a LPS vaccines.

Addition of the cholera toxin B subunit to oral and intranasal proteosome-Shigella flexneri 2a lipopolysaccharide vaccines improved their immunogenicities. Enhancement of anti-O-Shigella immunoglobulin A levels was most evident in lung lavages following oral immunization and in lung and intestinal fluids when suboptimal doses were used with either immunization route.

Administration, Intranasal↗
PubMed1994

Epidemic spread of Shigella sonnei shigellosis and evidence for development of immunity among children attending day-care centers in a communal settlement (Kibbutz).

An investigation of two Shigella sonnei shigellosis outbreaks that occurred in a communal settlement indicated that the transmission of the pathogen was restricted to day-care classes and secondary infection of family members was minimal. Development of serotype-specific immunity following S. sonnei infection was observed among infected children.

Bacteriophages↗
PubMed1994

Assessment of injury in transplanted and nontransplanted lungs after 6 h of cold storage with glutathione.

Single-lung transplantation after 3 h of hypothermic storage produces bilateral lung injury [pulmonary reimplantation response (PRR)]. We hypothesized that glutathione (GSH) hypothermic storage would protect both lungs from PRR for extended preservation times and that differences in injury and protection would be realized between the graft and the nontransplanted lung. Mongrel dogs underwent left single-lung autotransplantation after preservation for 5-6 h in Euro-Collins (EC) solution, EC plus exogenous GSH (EC+GSH), or Viaspan (VIA) at 4 degrees C. Lung injury was measured in both lungs after 1 h of reperfusion. EC dogs demonstrated significant increases in lung edema, lipid peroxidation, and alveolar neutrophil recruitment in the lung graft and to a less extent in the nontransplanted right lung compared with control dogs (P < 0.05). Edema, lipid peroxidation, and alveolar neutrophils were significantly reduced in both lungs from EC+GSH and VIA dogs compared with lungs from EC dogs (P < 0.05). An increase in large-pore permeability was measured in the lung graft from EC dogs compared with all other lungs. Bronchoalveolar lavage fluid lactate dehydrogenase and total protein concentrations were elevated in both lungs from all three groups of tranplanted dogs compared with those of control dogs (P < 0.05). These data suggest that GSH-containing solutions attenuate the PRR after 6 h of ischemic hypothermic storage but that the protection is incomplete. Mechanisms of injury affecting the lung graft during the PRR appear to differ from those affecting the nontransplanted lung.

Animals↗
PubMed1994

Insulin secretory abnormalities in subjects with hyperglycemia due to glucokinase mutations.

Pancreatic beta-cell function was studied in six subjects with mutations in the enzyme glucokinase (GCK) who were found to have elevated fasting and postprandial glucose levels in comparison to six normoglycemic controls. Insulin secretion rates (ISRs) were estimated by deconvolution of peripheral C-peptide values using a two-compartment model and individual C-peptide kinetics obtained after bolus intravenous injections of biosynthetic human C-peptide. First-phase insulin secretory responses to intravenous glucose and insulin secretion rates over a 24-h period on a weight maintenance diet were not different in subjects with GCK mutations and controls. However, the dose-response curve relating glucose and ISR obtained during graded intravenous glucose infusions was shifted to the right in the subjects with GCK mutations and average ISRs over a glucose range between 5 and 9 mM were 61% lower than those in controls. In the controls, the beta cell was most sensitive to an increase in glucose at concentrations between 5.5 and 6.0 mM, whereas in the patients with GCK mutations the point of maximal responsiveness was increased to between 6.5 and 7.5 mM. Even mutations that resulted in mild impairment of in vitro enzyme activity were associated with a > 50% reduction in ISR. The responsiveness of the beta cell to glucose was increased by 45% in the subjects with mutations after a 42-h intravenous glucose infusion at a rate of 4-6 mg/kg per min. During oscillatory glucose infusion with a period of 144 min, profiles from the subjects with mutations revealed reduced spectral power at 144 min for glucose and ISR compared with controls, indicating decreased ability to entrain the beta cell with exogenous glucose. In conclusion, subjects with mutations in GCK demonstrate decreased responsiveness of the beta cell to glucose manifest by a shift in the glucose ISR dose-response curve to the right and reduced ability to entrain the ultradian oscillations of insulin secretion with exogenous glucose. These results support a key role for the enzyme GCK in determining the in vivo glucose/ISR dose-response relationships and define the alterations in beta-cell responsiveness that occur in subjects with GCK mutations.

Adolescent↗
PubMed1994

Similar levels of mRNA from the W1282X and the delta F508 cystic fibrosis alleles, in nasal epithelial cells.

The effect of nonsense mutations on mRNA levels is variable. The levels of some mRNAs are not affected and truncated proteins are produced, while the levels of others are severely decreased and null phenotypes are observed. The effect on mRNA levels is important for the understanding of phenotype-genotype association. Cystic fibrosis (CF) is a lethal autosomal recessive disease with variable clinical presentation. Recently, two CF patients with mild pulmonary disease carrying nonsense mutations (R553X, W1316X) were found to have severe deficiency of mRNA. In the Jewish Ashkenazi CF patient population, 60% of the chromosomes carry a nonsense mutation, W1282X. Patients homozygous for this mutation have severe disease presentation with variable pulmonary disease. The presence of CF transcripts in a group of patients homozygous and heterozygous for this mutation was studied by reverse transcriptase PCR of various regions of the gene. Subsequent hybridization to specific CF PCR probes and densitometry analysis indicated that the CF mRNA levels in patients homozygous for the W1282X mutation are not significantly decreased by the mutation. mRNA levels were compared for patients heterozygous for the W1282X mutation. The relative levels of mRNA with the W1282X, and the delta F508 or the normal alleles, were similar in each patient. These results indicate that the severe clinical phenotype of patients carrying the W1282X mutation is not due to a severe deficiency of mRNA. In addition, the severity, progression, and variability of the pulmonary disease are affected by other, as yet unknown factors.

Alleles↗
PubMed1994

Higher maternal than paternal inheritance of diabetes in GK rats.

Results from crosses between Goto-Kakizaki (GK) rats, which exhibit spontaneous non-insulin-dependent diabetes mellitus (NIDDM), and outbred nondiabetic Wistar rats have demonstrated an effect of maternal inheritance on diabetes in offspring of the first generation (F1). At 6 weeks of age, F1 offspring of sex-directed crosses exhibited plasma glucose values intermediate between GK and Wistar parents. Hyperglycemia in F1 rats born of female GK rats (F1GK) was more marked than in those born of female Wistar (F1W) rats. At 3 months of age, F1 rats showed a marked impairment of both glucose tolerance and insulin secretion, which was intermediate between GK and Wistar rats. Glucose intolerance was more pronounced in F1GK rats than in F1W. By contrast, insulin secretion in F1W rats was more deteriorated than in F1GK rats. No deletion in mitochondrial DNA was observed in the GK rats, which decreased the possibility of a mitochondrial inheritance effect as an explanation of our findings. These data support a polygenic model in diabetes inheritance of NIDDM and suggest that, in addition to genetic factors, a perturbed maternal metabolism can contribute to its inheritance.

Animals↗