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Biomedical subjects

J Hernandez

Publications and source records attributed to J Hernandez.

At least 109 records · Page 6Linked to original sources
PubMed1994

Consanguineous matings in an Israeli-Arab community.

OBJECTIVE: To determine the frequency of consanguineous marriages and the inbreeding coefficient in Israeli Arabs. DESIGN: Cohort survey. SETTING: General community in 70 settlements in Israel. PARTICIPANTS: Nine thousand three hundred Israeli-Arab students in the second grade were sent questionnaires to be filled out by their fathers, with 8521 completed questionnaires returned. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Of the 8521 completed questionnaires, 1156 (14%) were from urban areas, 2267 (27%) were from suburban areas, and 5098 (60%) were from rural areas. The prevalence of consanguineous matings in the studied group was 44.3%, with a mean inbreeding coefficient of .0192. This prevalence is high and was highest in the rural areas. Marriages between first cousins occurred more often than marriages between other relatives in all locations. CONCLUSION: The frequency of consanguineous marriages is quite high among Israeli Arabs, approaching 50%.

Consanguinity↗
PubMed1994

Influence of topically applied cyclosporine A in olive oil on corneal epithelium permeability.

The effect that topically administered cyclosporine A (CsA) dissolved in olive oil has on corneal epithelial permeability was determined by fluorophotometry. Twenty-six healthy volunteers, who had no ocular or general disease and were not receiving any topical or systemic treatments, were studied. A Fluorotron Master fluorophotometer was used. Measurements were taken before and 45 min after the instillation of 40 microliters of a 2% aqueous solution of sodium fluorescein without preservatives. Basal corneal epithelial permeability, as well as the permeability 24 h after the instillation of 2% CsA-olive oil and of the solvent alone, were calculated. Under sterile conditions, the Sandimmun oral solution (Sandoz, Basel, Switzerland) was used to prepare the topical 2% CsA. Immediately after the 2% CsA-olive oil or the solvent alone were instilled, the volunteers complained of itching for approximately 1 h and developed punctate keratopathy, which improved the next day. Epithelial permeability 24 h after instillation of 2% CsA-olive oil increased 7.03 times (p < 0.001), and that of the solvent alone increased 6.68 times (p < 0.001). No differences in corneal permeability were found between CsA-olive oil and the vehicle (p = 0.651). We concluded that the olive oil used to dissolve CsA is responsible for the increased corneal epithelial permeability.

Administration, Topical↗
PubMed1994

Evidence for a cooperation between adenosine A2 receptors and beta 1-adrenoceptors on cardiac automaticity in the isolated right ventricle of the rat.

1. The effects of the adenosine receptor agonists, 5'-N-ethyl-carboxamidoadenosine (NECA) and 2-[4-(2-carboxyethyl)phenethylamino]-5'-N-ethylcarboxamidoadenosin e (CGS-21680) on ventricular automaticity induced by a local injury in the isolated right ventricle of the rat were studied. 2. In concentrations ranging from 0.1 to 100 nM, NECA significantly increased ventricular automaticity. This effect was more reproducible when the adenosine receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) was present at 5 nM, a concentration that blocks A1 adenosine receptors. 3. The excitatory effect of NECA was not observed when DPCPX was present at a concentration of 10 microM, which antagonizes both A1 and A2 adenosine receptors, as well as when rats were reserpinized. 4. In reserpinized rats, NECA increased ventricular automaticity in the presence of isoprenaline and the beta 2-adrenoceptor antagonist, ICI-118,551, but not in the presence of the beta 1-adrenoceptor antagonists, bisoprolol or atenolol. 5. The A 2s-selective adenosine receptor agonist, CGS-21680 (0.1 nM-10 microM) was devoid of excitatory effect on ventricular automaticity. Binding studies of this compound to the rat ventricular membranes revealed that in the preparation there was no specific binding. 6. These results suggest that the excitatory effect of NECA on ectopic ventricular automaticity is dependent on endogenous catecholamines and is mediated by an A2 adenosine receptor which is in some way 'linked' to the beta 1-adrenoceptor. These A2 receptors do not appear to be of the A2a adenosine receptor subtype.

Adenosine↗
PubMed1994

Human cytomegalovirus elevates levels of the cellular protein p53 in infected fibroblasts.

Human cytomegalovirus (HCMV), like other DNA tumor viruses, induces morphological transformation of cells in vitro and stimulates host cell macromolecular synthesis in infected cells. Since other DNA tumor viruses, such as simian virus 40 and adenovirus, have previously been shown to interact with cellular protein p53, we investigated whether infection of cells by HCMV would modulate cellular p53 levels. Our results indicate that HCMV elevates cellular p53 levels on the order of 10- to 20-fold in infected fibroblasts. The induction of elevated p53 levels was dependent upon the presence of active virus and was prevented by neutralizing antibody. The induction of elevated p53 levels was determined not to be due to virus-receptor interactions or HCMV late events. The induction of elevated p53 levels commenced at immediate-early times of the HCMV multiplication cycle (6 h postinfection) and reached maximal levels by 24 h postinfection, before most of the HCMV DNA synthesis was initiated. HCMV immediate-early proteins were clearly shown to be responsible for elevating p53 levels in infected fibroblasts; expression of HCMV immediate-early region 1 and 2 proteins resulted in elevation of p53 levels in transfected human fibroblasts. This is the first report of increased p53 levels caused by HCMV in infected fibroblasts.

Antigens, Viral↗
PubMed1994

Regulation of metallothionein concentrations in rat brain: effect of glucocorticoids, zinc, copper, and endotoxin.

The effects of known inducers of liver metallothionein (MT) synthesis on MT concentrations in the rat brain have been determined using antibodies that are specific for MT I and II and do not cross-react with MT III. There were substantial differences in the MT concentrations in different areas of the brain. Dexamethasone increased MT levels after 24 h in the frontal cortex, cortex, medulla oblongata plus pons, midbrain, striatum, hippocampus, and cerebellum but not in the hypothalamus. Corticosterone produced similar results except in the hippocampus. Long-lasting adrenocorticotropic hormone increased MT concentrations after 12 h in midbrain and striatum but not in the liver. Adrenalectomy decreased MT concentrations after 6 days in the medulla oblongata plus pons, striatum, hippocampus, and hypothalamus but increased concentrations in the liver and kidneys; these effects were reversed by corticosterone. The role of glucocorticoids in the regulation of MT levels therefore differs between tissues and within specific areas of the brain. Injection of zinc or copper intracerebroventricularly and the use of a zinc-deficient diet increased and decreased MT levels, respectively, in some but not all brain areas. Endotoxin increased liver MT but not brain MT I levels after 8 h.

Adrenalectomy↗
PubMed1994

Spontaneous pneumothorax. Long-term results with tetracycline pleurodesis.

The aim of this prospective study was to determine the rate of recurrence for spontaneous pneumothorax (SP) after tetracycline pleurodesis (TCP), using that of observation, tube thoracostomy alone, and thoracotomy as references. From 1985 to the end of 1991, 78 patients were treated with tetracycline pleurodesis and 135 patients served as control subjects. Pleurodesis was induced by instillation of tetracycline and ascorbic acid through the pleural drain. The indication was any SP treated with tube thoracostomy, without active pulmonary infection. Follow-up period was from 13 to 95 months (mean, 45 months); follow-up rate was 94 percent. Post-therapy surgery was necessary for eight patients in whom pleurodesis failed due to presence of a persistent air leak. The ipsilateral recurrence rate of patients treated with TCP was 9 percent (6/66) and recurrence time ranged from 2 days to 9 months. The recurrence rate for patients treated with observation was 36 percent, 35 percent for those having chest tube alone, and none for those undergoing surgery. No death occurred as a direct result of this procedure and all patients could be released from the hospital. Eleven subjects died during the follow-up period; the mean follow-up until death was 37 months (range, 2 to 87 months). Five deaths were due to respiratory causes and six were due to extrapulmonary causes. Tetracycline pleurodesis has been shown to be a good alternative for the prevention of recurrence of SP. Its recurrence rate is lower than that of tube drainage but higher than that of surgical treatment.

Adolescent↗
PubMed1993

PCR-based restriction fragment length polymorphism analysis of DNA sequence diversity of flagellin genes of Campylobacter jejuni and allied species.

Genotypes were analysed within 29 geographically diverse strains of Campylobacter jejuni mainly from human enteritis cases and four strains representing C. coli, C. lari and C. helveticus. A 1723 bp DNA fragment, amplified by the polymerase chain reaction (PCR) from the flagellin (fla) genes, was used to probe genomic Southern blots for restriction site variation at homologous loci. Internal Hin fl restriction fragment length polymorphisms (RFLP) of the fla gene PCR amplification product were also used to characterize isolates. Copy number and polymorphisms in and around the fla genes were detected, and strains were grouped into 10 genotypes on the basis of fla restriction site similarities. Campylobacter jejuni had a fla gene copy number of two and the majority (64%) of strains in the species had common internal fla gene sequences as indicated by Hin fl restriction analysis. A greater degree of diversity was detected around the fla loci in Hae III and Bgl II genomic Southern blots. The results showed that analysis of fla genes provided a novel and fundamental approach to grouping strains and offered a basis for defining a predominant clonal evolutionary line within C. jejuni.

Base Sequence↗
PubMed1993

Effect of stress, adrenalectomy and changes in glutathione metabolism on rat kidney metallothionein content: comparison with liver metallothionein.

Eighteen hours of immobilization stress, accompanied by food and water deprivation, increased liver metallothionein (MT) but decreased kidney MT levels. Food and water deprivation alone had a significant effect only on liver MT levels. In contrast, stress and food and water deprivation increased both liver and kidney lipid peroxidation levels, indicating that the relationship between MT and lipid peroxidation levels (an index of free radical production) is unclear. Adrenalectomy increased both liver and kidney MT levels in basal conditions, whereas the administration of corticosterone in the drinking water completely reversed the effect of adrenalectomy, indicating an inhibitory role of glucocorticoids on MT regulation in both tissues. Changes in glutathione (GSH) metabolism produced significant effects on kidney MT levels. Thus, the administration of buthionine sulfoximine, an inhibitor of GSH synthesis, decreased kidney GSH and increased kidney MT content, suggesting that increased cysteine pools because of decreased GSH synthesis might increase kidney MT levels through an undetermined mechanism as it appears to be the case in the liver. However, attempts to increase kidney MT levels by the administration of cysteine or GSH were unsuccessful, in contrast to what is known for the liver. The present results suggest that there are similarities but also substantial differences between liver and kidney MT regulation in these experimental conditions.

Adrenal Glands↗
PubMed1993

Molecular subtyping by genome and plasmid analysis of Campylobacter jejuni serogroups O1 and O2 (Penner) from sporadic and outbreak cases of human diarrhoea.

Ribosomal RNA gene patterns, randomly amplified polymorphic genomic DNA (RAPD) profiles and plasmid profiles were used to discriminate between 28 strains of Campylobacter jejuni serogroups O1 and O2 (Penner). Most isolates were biotype I (Lior). The strains were representative isolates from a UK school outbreak of enteritis (7 cases) and from 21 sporadic human cases of enteritis in 4 countries. The molecular techniques discriminated to various degrees between strains in each of the serogroups. The outbreak strains were homogeneous in most molecular features but a variety of types was detected amongst the isolates from the sporadic cases. Five groups of two or more strains with identical ribopatterns were identified and within each, strains from different patients were homogenous with respect to serogroup. RAPD profile typing based on numerical analysis generally matched ribotyping. Plasmid profiling overall gave least discrimination but was useful in separating some strains similar in other features. We concluded that optimal discrimination of C. jejuni could best be achieved using a combination of phenotypic and genotypic properties. Hae III ribotyping was the single most discriminatory and reproducible technique investigated. Several strains of C. jejuni from sporadic infections had similar molecular profiles which have potential for general typing purposes.

Bacterial Typing Techniques↗
PubMed1993

Iatrogenic diseases in the surgery of the ear.

We made a retrospective study of 419 cases, who had undergone otological surgery for different reasons. In 55 of them we judged, that the pathology, may have been due to the previous surgery carried out in different hospitals. The disease encountered may have been iatrogenic. We have proceeded analyse of the probable cause and to suggest some techniques for dealing with the problem. We have also suggested criteria for the surgery and for the prevention of this occurrence.

Cholesteatoma↗
PubMed1992

Ribosomal RNA gene restriction fragment diversity amongst Lior biotypes and Penner serotypes of Campylobacter jejuni and Campylobacter coli.

Diversity based on ribosomal RNA gene-restriction endonuclease digest patterns was detected amongst 42 strains of Campylobacter jejuni and 18 strains of C. coli including representatives of 53 different Penner serotypes. HaeIII ribopatterns were coded for numerical analysis which showed that all except two were different including those of several strains of the same serotype (P2 and P20). At the 30% similarity level, four groupings were formed in the analysis of which three corresponded to C. jejuni, C. coli and C. lari phenotypes respectively. Eight strains (13%) were atypical as their phenotypic and ribopattern associations did not correspond. Ribopattern fragments of 3.0, 5.0 and 9.3 kb were characteristic of the majority of C. jejuni, whereas 1.5, 2.2-, 2.3- and 4.7-kb fragments were commonly present in C. coli. These fragments provided novel species-specific markers. We conclude that HaeIII ribotyping was as discriminatory as Penner serotyping of C. jejuni and C. coli and may even provide a basis for distinguishing between strains of the same serotype and for identifying new groups within the thermophilic campylobacters.

Bacterial Typing Techniques↗
PubMed1992

Characterization of the effects of human placental HGF on rat hepatocytes.

Hepatocyte growth factor (HGF) also known as hepatopoietin A (HPTA) (Michalopoulos, FASEB J., 4:176-187, 1990) is a heparin-binding growth factor whose characterization and tissue distribution have been reported elsewhere. This growth factor was recently cloned and its amino acid sequence determined under the name of hepatocyte growth factor (HGF) (Miyazawa et al., Biochem. Biophys. Res. Commun., 163:967-973, 1989; Zarnegar et al., Biochem. Biophys. Res. Commun., 163:1370-1376, 1989; Nakamura et al., Nature, 342:440-443, 1989). Human placenta is one of the tissues that contains significant amounts of HGF. We isolated HGF from human placenta and characterized its biologic effect on rat hepatocytes. Human placenta HGF was isolated in high purity as a single chain molecule. Single chain HGF stimulated DNA synthesis in primary rat hepatocyte cultures in serum-free medium. The maximal effect was seen at 5-10 ng/ml. The maximal response occurred at 25-48 hours after plating of the hepatocytes. Protein synthesis was also stimulated by HGF in primary rat hepatocyte cultures. There were peak responses at 19-24 and 37-42 hours after plating of the hepatocytes. TGF beta 1 inhibited more than 95% of HGF-induced DNA synthesis but only 25% of HGF-induced protein synthesis. HGF interacted in an additive manner with EGF, a well-known hepatocyte mitogen. There was not an additive interaction between HGF and aFGF. Regenerating liver hepatocytes obtained from rats which underwent two-thirds partial hepatectomies (PHX) also responded to HGF in a dose-dependent manner as the hepatocytes from normal liver.

Animals↗
PubMed1992

Frequency domain models of the EEG.

The structure of the normal resting EEG crosspectrum SVV(omega) is analyzed using complex multivariate statistics. Exploratory data analysis with Principal Component Analysis (PCA) is followed by hypothesis testing and computer simulations related to possible neural generators. The SVV(omega) of 211 normal individuals (ages 5 to 97) may be decomposed into two types of processes: the xi process with spatial isotropicity reflecting diffuse, correlated cortical generators with radial symmetry, and processes that seem to be generated by more spatially concentrated, correlated sources. The latter are reflected as spectral peaks such as the process. The eigenvectors of the xi process are the Spherical Harmonic Functions which explains the recurring pattern of maps characteristic of the spatial PCA of qEEG data. A new method for estimating sources in the frequency domain which fits dipoles to the whole crosspectrum is applied to explain the characteristics of the localized sources.

Age Factors↗
PubMed1992

The arterial wall response to intimal injury in an experimental model.

Repair of occult arterial injuries is advocated to prevent thrombosis, arteriovenous fistula, and pseudoaneurysm formation. However, recent clinical series describe the healing of arterial intimal injuries and recommend nonoperative therapy. To investigate the arterial wall response to intimal injury, we created intimal flaps in 46 canine femoral arteries. The intimal flaps were imaged by arteriography, angioscopy, and intravascular ultrasound acutely, and at one and three weeks and five months post-injury. Lumen area was measured using caliper techniques (arteriography) and computerized video planimetry (angioscopy, intravascular ultrasound). Intimal and medial thickness were measured by intravascular ultrasound prior to harvest for histologic evaluation by light microscopy. Analysis of 32 patent arteries was performed after exclusion of 14 thrombosed arteries. Residual lumen area (mm2) correlated closely among the imaging modalities at one week (8.7 +/- 1.1, 7.3 +/- 2.0, 6.9 +/- 1.8), three weeks (4.2 +/- 0.9, 2.9 +/- 1.0, 2.7 +/- 0.8), and five months (5.3 +/- 0.9, 5.0 +/- 0.5, 5.0 +/- 0.9). Maximal intimal and medial thickness occurred three weeks post-injury, coincident with the maximal reduction in lumen area. Although intimal injuries can cause acute and delayed arterial thromboses, observation may be appropriate in selected cases. The evaluation of those patients chosen for nonoperative therapy should extend beyond three weeks, as this is the time of maximal arterial wall response with a continued potential for adverse clinical events.

Analysis of Variance↗