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R Hernandez

Publications and source records attributed to R Hernandez.

At least 145 records · Page 8Linked to original sources
PubMed1992

Role of oxygen-derived free radicals on rat splanchnic eicosanoid production during acute hemorrhage.

The effect of superoxide dismutase (SOD), an oxygen-derived free radical scavenger, on rat splanchnic eicosanoid synthesis was examined following hemorrhagic shock. Anesthetized male rats were hemorrhaged to 30 mm Hg for 30 minutes (Shock), killed, or treated with the shed blood (Shock plus reperfusion). The Shock plus reperfusion group was treated with saline vehicle or SOD (2500, 5000, 7500, 10,000 or 15,000 U/Kg, i.v.) 15 minutes prior to the reperfusion of the shed blood. The superior mesenteric artery was removed in continuity with the end organ intestine (SV+SI) and perfused in vitro with oxygenated Krebs-Henseleit buffer (3 ml/min at 37 degrees C). Venous effluent was measured for basal release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 at 15, 30, 60 and 90 minutes of perfusion. The SV+SI compensated for acute shock by increased release of 6-keto-PGF1 alpha (300%) (and not PGE2 or thromboxane B2) which was abolished by reperfusion of the shed blood following shock. Prior treatment of the Shock plus reperfusion group with 7500 U/Kg or more of SOD restored the increased release of SV+SI 6-keto-PGF1 alpha found following shock alone (p less than 0.05). These data provided indirect evidence that ODFRs contributed to endogenous SV+SI regulation of PGI2 synthesis and release during hemorrhagic shock and reperfusion of shed blood.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

Mouse genomic DNA sequences homologous to sea urchin TU elements are genetically stable polydispersed repeats useful for analysis of multiple RFLPs.

Segments of the murine genome that hybridize to the inverted repeat regions of the transposable TU elements of sea urchins include tandem repeats of a sequence (CTCC) that encodes the recognition site for the restriction enzyme Mnl1, as do the analogous polypurine/polypyrimidine (pPu/pPy) stretches in humans. The Mnl1-sensitive repeats, which exist as a microsatellite sequence 200-300 bp in length, lack the terminal dyad symmetry characteristic of the TU elements and are structurally and functionally distinct from these elements. DNA fragments containing these repeat units that are isolated from different generations of isogenic (or congenic) mice or from different tissues of genetically identical individuals are indistinguishable by RFLP analysis; however, they show restriction fragment length polymorphism in different strains. This polymorphism appears to reflect DNA sequence changes occurring at sites flanking the repeats rather than variability in the number of repeats. Their genetic stability and occurrence in a wide variety of animal species make the Mnl1 repeats useful in studying genetic variation that has occurred over an evolutionary time scale of greater duration than can be examined conveniently by VNTR analysis.

Animals↗
PubMed1992

Evaluation of a colorimetric Babesia bigemina-DNA probe within an epidemiological survey.

An epidemiological survey was conducted in southeast Mexico, in an effort to establish the serological reactivity and carrier status to Babesia bigemina of an indigenous cattle population. The prevalence was obtained through the Indirect Fluorescent Antibody Test (IFAT), using an in vitro culture-derived B. bigemina antigen. A specific, digoxigenin-coupled, approximately 6 Kb B. bigemina-DNA probe (BBDP), was used to indicate the presence of the parasite. Serum samples from 925 animals of all ages, were obtained within the three regions (I, II, III) of the state of Yucatan and tested by IFAT. In addition, whole blood samples drawn from 136 of the same animals of region II were analyzed using the BBDP. Positive IFAT (IFAT+) reactions were observed in 531 sera for a 57% overall prevalence. Regional values were: I = 157+ (56%), II = 266+ (68%) and III 108+ (42%). Only 32 (23%) of the blood samples tested with BBDP showed distinctive hybridization signal, in contrast with 100 (73%) IFAT+ animals. The response distribution for IFAT vs. BBDP was: +/+ 23, +/- 77, -/+ 9 and -/- 27 respectively. It was found that the analytical sensitivity of BBDP appears to be low for its utilization in widespread epidemiological surveys. It was considered, however, that the colorimetric probe might be useful to safely detect transmission prone carriers, since it is able to detect parasitemias as low as 0.001%.

Age Factors↗
PubMed1992

Molecular characterization of Mexican stocks of Trypanosoma cruzi using total DNA.

Seventeen Mexican Trypanosoma cruzi stocks and five South American reference strains were analyzed by Hind III restriction fragment length polymorphisms associated with ribosomal RNA gene spacers and by HinfI digestion patterns of total DNA. Our findings demonstrate the occurrence of genetic heterogeneity within these stocks. Hierarchic and non-hierarchic clustering of these molecular characters allowed the formation of groups that correlate with the geographic origin of the stocks. The HinfI digestion pattern permitted the identification of DNA fragments from the kinetoplast maxi-circles, and therefore represents a simple and convenient method for conducting epidemiologic surveys in laboratories in developing countries.

Animals↗
PubMed1992

Oxygen free radical regulation of rat splanchnic blood flow.

BACKGROUND: The role of oxygen-derived free radicals on splanchnic prostaglandin (PGI2) synthesis and superior mesenteric artery (SMA) blood flow was examined during acute hemorrhage. METHODS: Sprague-Dawley rats were hemorrhaged to 30 mm Hg for 5, 30, or 45 minutes without (SK5, SK30, and SK45) or with (SK5 + R, SK30 + R, and SK45 + R) blood reperfusion. The SK30 + R and SK45 + R groups were treated with or without superoxide dismutase (10,000 units/kg intravenously). In vivo SMA blood flow was measured continuously for 100 minutes by a transonic flow probe, or in other groups the in vitro-perfused SMA and its end-organ intestine (SV+SI) were assayed for release of PGI2 by radioimmunoassay after 15 and 30 minutes of perfusion. RESULTS: Acute hemorrhage at all time periods increased SV+SI PGI2 release twofold to threefold compared with sham animals (p less than 0.01), which was abolished after blood reperfusion. SMA blood flow was decreased by 79.6% +/- 3.3% and 88.2% +/- 1.4% in the SK30 + R and SK45 + R groups compared with the sham animals (p less than 0.01). Superoxide dismutase treatment restored both SV+SI release of PGI2 after SK and SMA blood flow to control levels. CONCLUSION: Oxygen-derived free radicals locally produced during SK30 + R and SK45 + R inhibited splanchnic PGI2 synthesis, which contributed to decreased splanchnic blood flow.

Acute Disease↗
PubMed1991

Congenital cutaneous candidiasis: report of four cases and review of the literature.

Congenital cutaneous candidiasis (CCC) is a rare disease acquired by an ascending route, liable to affect the offspring of pregnant women suffering from vulvovaginitis. The cutaneous lesions are present at birth or within the first hours of life. Some infants may present with respiratory distress or clinical signs of sepsis during the first 2 days of life. We report four new cases of CCC, three of which presented transient respiratory distress and clinical signs of sepsis with hepatosplenomegaly. The evolution was favourable in all three cases with topical and oral therapy. We emphasize the self-limited character of this disease, although preterm infants may be at risk of systemic spread. Only one infant presented paronychia as a late complication.

Candidiasis↗
PubMed1991

Pharmacokinetics and distribution of ketamine after extradural administration to dogs.

We have studied the pharmacokinetics and distribution of ketamine and its biotransformation products in dogs after extradural administration of ketamine at L4-5. The mean apparent uptake rate constants of ketamine for plasma and CSF were 4.17 (SD 1.84) and 5.15 (2.50) h-1, respectively. The concentrations of ketamine in CSF were greater than those found in plasma. The elimination half-life values of the parent drug for both biological fluids were similar (4.3 (2.96) h and 4.6 (3.31) h for plasma and CSF, respectively). The apparent formation rate constant of norketamine was greater than that of dehydronorketamine. However, the concentrations of the biotransformation products in CSF were smaller than those of the parent drug. These results are similar to the distribution of ketamine and its metabolites in different cerebral structures and tissues. The concentrations decreased in concert with the increase in polarity of the metabolites. A specific distribution for all compounds was observed. Ketamine showed a greater affinity for brainstem, while norketamine and dehydronorketamine were distributed mostly in cerebellum and kidney, respectively.

Anesthesia, Epidural↗
PubMed1991

A double-blind, parallel, comparative evaluation of amlodipine vs. captopril in the monotherapeutic treatment of mild and moderate essential hypertension.

A double-blind, parallel, comparative study of the antihypertensive efficacy and safety of once-daily oral doses of amlodipine (5-10 mg/day) vs. twice-daily oral doses of captopril (25-50 mg twice daily) in adult patients with mild or moderate essential hypertension (supine diastolic blood pressure of 95-115 mm Hg) was undertaken in two hospital centers. Interim analysis of data from 40 patients shows that amlodipine and captopril both significantly (p < 0.05) reduced blood pressure compared with baseline. Nineteen of 21 (90.5%) amlodipine-treated patients and 15 of 19 (78.9%) captopril-treated patients had their diastolic blood pressure "normalized" (< 90 mm Hg) with mean final doses of 8.2 and 76.7 mg/day, respectively. At the final visit, there were no statistically significant differences between the two treatment groups in either mean supine or standing blood pressure. Minor nonsignificant changes in standing heart rate were observed in both treatment groups. Seven of the 21 amlodipine-treated patients and 3 of the 19 captopril-treated patients reported adverse experiences. No patients in either treatment group discontinued due to adverse events; one patient in the amlodipine group required a dose reduction. These interim data indicate that the overall efficacy and safety profiles of these two drugs are comparable.

Adult↗
PubMed1991

Subarachnoid hemorrhage from multiple neurofibromas of the cauda equina: case report.

The authors report a case of spinal subarachnoid hemorrhage caused by neurofibromas of the cauda equina. An examination of the literature revealing 13 similar cases and an analysis of this case showing three neurofibromas of the cauda equina prompted an hypothesis emphasizing the origin of bleeding and the difficulties associated with a correct diagnosis.

Cauda Equina↗
PubMed1990

["Precursor phenomena" as a criterion in the choice of prevention of primary headache of the hemicrania type].

The importance of headache precursors as expression of latent headache is emphasized. The authors report data from a clinical-epidemiological survey of 322 youngster (143 m and 179 f) aged 4-16 with primary headache aimed at assessing latent time between precursors and onset of headache. The appearance of precursors is considered the time appropriate for prophylaxis.

Adolescent↗
PubMed1990

An incentive program to increase revenue in a public hospital.

Using financial reward systems to enhance revenue generation or promote cost savings has been more difficult in public than in private hospitals. The program at the Los Angeles County-University of Southern California Medical Center has demonstrated, however, that it can be done.

Cost Control↗
PubMed1990

[Periodontal treatment needs in a Spanish school population].

The aim of this study was to assess the periodontal treatment needs of the population under 20 years of age in Spain. 1469 young people, aged 7, 12 and 15-19 years, and representing the urban (60%) and rural (40%) population from Spain were evaluated using the Community Periodontal Index of Treatment Needs (C.P.I.T.N.). In the first age group (7 years), 12% presented calculus or overhanging restorations, and 45% had bleeding upon probing only. In the age group of 12 years the proportion of individuals with calculus, overthanging restorations or moderate pocket depths was 39%, while 38% had gingivitis as their highest treatment need. In the oldest group (15-19 years) the number of subjects with bleeding upon probing decreased to 17%, while the percentage of individuals having moderate pockets, calculus or overhanging restorations increased to 67%. 1% of this youngsters had pockets of 6 mm. or over. At age 7, only 30% had "acceptable gingival health", and no more than 15% of the 18 year-olds reached this condition.

Adolescent↗
PubMed1990

Assessment of need for multicompetent allied health practitioners in the midlands of South Carolina.

Recent attention has focused on integration of Multicompetent Allied Health Practitioners (MCAHPs) into the health care labor force to offset future imbalances in supply and demand for allied health practitioners, and to maximize use of existing allied health practitioners. Several recent studies have focused on multicompetency issues. However, there is little that shows the impact of MCAHPs on health care costs. This study was conducted to determine the current usage of MCAHPs, projected future need for them, needs-skill combinations, entry-level salary comparison between MCAHPs and single-skilled practitioners, projected yearly savings in personnel costs to health care organizations employing MCAHPs, and community support for a college-based MCAHP program. Results indicated a large market for MCAHPs, increased entry-level salaries for MCAHPs compared to single-skilled practitioners, and projected savings to health care institutions due to decreased personnel costs.

Allied Health Personnel↗
PubMed1989

Effects of flecainide on defibrillation thresholds in the anesthetized dog.

The effects of flecainide on defibrillation thresholds in 21 open chest, anesthetized dogs were studied. Defibrillation was accomplished using nontruncated exponential pulses delivered through two epicardial patches. Multiple shocks of varying energy were administered after 10 s of ventricular fibrillation in random order. The percent success was plotted against the energy delivered for each dog. A sigmoidal curve was fit to the data and the energy associated with 50% success (E50) calculated. Flecainide (n = 16) or saline solution (n = 5) was then infused and E50 again determined. Flecainide infusion produced mean (+/- standard error of the mean) plasma levels of 610 +/- 111 ng/ml. Defibrillation thresholds were obtainable in 10 of 16 dogs that received flecainide infusion. Flecainide infusion increased E50 by 75% (from 6.5 +/- 1.9 to 11.4 +/- 2.6 J) (P less than 0.05). Infusion of saline solution did not significantly affect defibrillation energy. Of 16 dogs that received flecainide infusion, 12 had one or more complications: 6 had ventricular fibrillation resistant to defibrillation, 6 developed severe hypotension after successful defibrillation and 5 had spontaneous ventricular fibrillation after successful defibrillation. These effects were not seen in any control dogs. Flecainide infusion significantly increases defibrillation threshold and has important adverse arrhythmic and hemodynamic effects in this experimental preparation.

Animals↗
PubMed1989

Bradycardia-dependent block and fatigue phenomenon of the His-Purkinje system manifested during upright tilt.

Atrioventricular (AV) block occurring in the His-Purkinje system may occur sporadically and can be difficult to document. In this article, we describe two patients with spontaneous episodes of AV block, in whom the use of upright tilt during electrophysiological testing led to a diagnosis of His-Purkinje disease. In both cases, testing in the supine position only uncovered mild or no abnormalities of infra-nodal conduction. In the first case, high grade block distal to the His occurred and the mechanism appeared to be bradycardia-dependent block. In this case, increased sympathetic tone due to upright tilt may have enhanced the slope of phase 4 depolarization in abnormal His-Purkinje cells, leading to block. In the second case, high grade block distal to the His was seen with upright tilt and the mechanism of block appeared to be fatigue phenomenon in the His-Purkinje system. These cases emphasize the elusive nature and varied mechanisms of His-Purkinje block and illustrate the utility of electrophysiological testing in the upright position in patients with suspected conduction system disease.

Adult↗