Biomedical subjects

C Flores

Publications and source records attributed to C Flores.

At least 73 records · Page 4Linked to original sources

PubMed1991

The clinical and immunologic response of Chilean infants to Haemophilus influenzae type b polysaccharide-tetanus protein conjugate vaccine coadministered in the same syringe with diphtheria-tetanus toxoids-pertussis vaccine at two, four and six months of age.

The safety and immunogenicity of a vaccine against Haemophilus influenzae type b consisting of purified polyribosylribitolphosphate conjugated to tetanus toxoid (PRP-T) was evaluated in 278 Chilean infants who were randomly assigned to one of three treatment groups: Group A, PRP-T mixed with diphtheria-tetanus toxoids-pertussis (DTP) vaccine in a single syringe and given as a single inoculation in one arm and placebo in the other arm; Group B, PRP-T given in one arm and DTP in the other arm; Group C, DTP given in one arm and placebo in the other. Infants were immunized at 2, 4 and 6 months of age and examined daily for 4 days after each immunization; serum PRP antibodies were measured at baseline and 2 months after each dose. The only adverse systemic reaction attributable to PRP-T beyond that caused by DTP alone was a 7 to 20% increase in febrile responses in the first 24 hours after the first and second doses of vaccine; the fevers were largely low grade and not accompanied by increased irritability, diminished activity or loss of appetite, compared with the group who received DTP without PRP-T. After the first dose 72% of infants who received PRP-T combined with DTP and 67% who received it in a separate arm attained antibody concentrations greater than or equal to 0.15 micrograms/ml. After two doses of PRP-T, 93 and 95%, respectively, had concentrations greater than or equal to 0.15 microgram/ml and after three doses 100% of infants who received PRP-T had such titers.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗

PubMed1990

DNA sequence analysis of five genes; tnsA, B, C, D and E, required for Tn7 transposition.

A region of DNA sequence of the bacterial transposon Tn7, which is required for transposition, has been determined. This DNA sequence completes an 8351 base pair (bp) region containing five long open reading frames (ORF's) that correspond to the genetically defined genes, tnsA, B, C, D and E, required for Tn7 transposition. All of the ORF's are oriented in the same direction, ie. inward from the element's right end. The genes are in a very compact arrangement with the presumed initiation codons never more than two bases beyond the preceding termination codon. Domains with similarity to the helix-turn-helix genre of Cro-like, sequence specific DNA binding sites occur within the deduced amino acid (a.a.) sequence of the TnsA, TnsB, TnsD and TnsE proteins. Translation of the tnsC ORF reveals strong homology to a consensus sequence for nucleotide binding sites as well as a region of similarity to a transcriptional activator (MalT). No striking a.a. sequence similarity to other DNA recombinases is observed. The possible roles of these proteins in Tn7 transposition is discussed in light of the analysis presented.

Amino Acid Sequence↗

PubMed1990

Reversal of the toxic effects of cyclosporine on male reproduction and kidney function of rats by simultaneous administration of hCG + FSH.

We have shown earlier that the administration of cyclosporine impairs testicular function and causes a decrease in sperm counts, sperm motility and fertility. In order to determine whether or not the deleterious effects of CsA could be reversed by hormonal therapy, we injected sexually mature male Sprague Dawley rats with cremaphor + saline or CsA (40 mg./kg./d) alone or in combination with human chorionic gonadotropin (hCG; five micrograms./d/rat) and follicle stimulating hormone (FSH; five micrograms./d/rat). The injections were given subcutaneously for 14 days. As expected, CsA administration decreased the body and reproductive organ weights, testicular and epididymal sperm counts, sperm motility and fertilizing ability. Serum levels of LH were elevated and testosterone was decreased. The administration of FSH + hCG to the CsA treated rats restored the body and reproductive organ weights, sperm counts and motility. Seventy five percent of gonadotropin treated males were fertile as compared to 25% in the CsA treated group. In the hormone treated group, the blood levels of CsA were 50% of that of CsA treated group. In order to verify whether or not the decline in the blood levels of CsA was the cause for the amelioration of CsA-induced changes in the reproductive function, we compared the CsA + hormone treated group with another group treated with five mg./kg./d CsA which had blood levels of CsA comparable to the former group. In the five mg./kg./d group the reproductive functions were significantly lower than the CsA + hormone treated group suggesting, therefore, that the restoration of reproductive functions in the CsA + hormone treated group is a result of hormonal treatment. Administration of CsA (40 mg./kg./d) reduced the kidney weight and increased the levels of serum creatinine: these changes were also ameliorated by the administration of hCG + FSH.

Animals↗

PubMed1990

Evaluation of the effect of experimental cyclosporine toxicity on male reproduction and renal function. Reversal by concomitant human chorionic gonadotropin administration.

Administration of cyclosporine to rats has been shown to impair testicular function, resulting in a decrease in sperm counts and fertility. In order to determine whether or not the deleterious effects of CsA could be reversed by hormonal therapy, mature male Sprague Dawley rats were treated with CsA (40 mg/kg/day, s.c.) alone or in combination with human chorionic gonadotropin (hCG) (5 micrograms/day/r; s.c.) for 14 days. Cyclosporine administration decreased the body weight (290 +/- 5.30 vs. 339 +/- 8.7 g; P less than 0.05) and reproductive organ weights (testis 1.49 +/- 0.42 vs. 1.60 +/- 0.03 g; epididymis 0.41 +/- 0.02 vs. 0.49 +/- 0.002 g; seminal vesicle 0.61 +/- 0.09 vs. 1.60 +/- 0.05 g; prostate 0.28 +/- 0.04 vs. 0.60 +/- 0.06 g; P less than 0.05) testicular sperm counts (5.80 +/- 0.42 vs. 8.49 +/- 0.48 x 10(7)/100 mg tissue; P less than 0.05) and epididymal sperm counts, (28.2 +/- 0.95 vs. 51 51.62 +/- 2.17 x 10(7)/100 mg tissue; P less than 0.05) and fertility (25% vs. 100%). Serum levels of LH were elevated (101.98 +/- 21.48 vs. 25.6 +/- 5.18 ng/ml; P less than 0.05) and testosterone was decreased (0.48 +/- 0.07 vs. 2.06 +/- 0.56 ng/ml; P less than 0.05). The administration of hCG to the CsA-treated rats restored the reproductive organ weights (testis 1.56 +/- 0.043 g; seminal vesicle 1.04 +/- 0.05 g; prostate 0.70 +/- 0.06 g) and sperm counts (testicular 7.88 +/- 1.0 x 10(7)/100 mg tissue; epididymal 59.86 +/- 4.16 x 10(7)/100 mg tissue; P less than 0.05) Serum levels of testosterone (18.63 +/- 4.45 ng/ml) and LH (431.65 +/- 31.41 ng/ml) were significantly elevated, as compared with control and CsA-treated groups (P less than 0.05). All the rats in the gonadotropin-treated group were fertile, as compared with 25% in the CsA-treated group. CsA reduced the kidney weight (1.17 +/- 0.02 vs. 1.27 +/- 0.03 g; P less than 0.05) and increased the levels of serum creatinine (0.97 +/- 0.07 vs. 0.59 +/- 0.03 mg/dl; P less than 0.05): these changes were ameliorated by the administration of hCG (kidney weight 1.35 +/- 0.03 g; creatinine 0.76 +/- 0.09 mg/dl).

Animals↗

PubMed1989

Menstrual patterns and progesterone circulating levels following different procedures of tubal occlusion.

This study was undertaken to assess the effects of different tubal occlusion procedures on ovarian function. Three groups of subjects randomized to tubal occlusion by laparoscopy and Yoon ring (24 subjects), minilaparotomy and Yoon ring (19 subjects) and minilaparotomy and Pomeroy (22 subjects), and one separate control group of 26 healthy subjects not using any form of contraception were studied in a prospective design. The characteristics of the menstrual patterns were studied for one year after sterilization. Determination of the circulating progesterone levels were made on days 15, 20 and 25 of menstrual cycles initiated 1, 3, 6 and 12 months following the tubal ligation. In the analysis of the bleeding pattern there was a statistically significant difference in the mean segment length and in the longest bleeding-free interval in the subjects who had been sterilized by minilaparotomy with Yoon ring, when compared to the other two study groups and to the control group. However, the magnitude of this difference in number of days was not considered clinically significant. There was no statistically significant difference in the percentage of ovulatory cycles within the study and the control groups, or when the results of the study groups were compared with each other or to the control group.

Adult↗

PubMed1988

A new and sensitive method for measuring thermal nociception in cutaneous hyperalgesia.

A method to measure cutaneous hyperalgesia to thermal stimulation in unrestrained animals is described. The testing paradigm uses an automated detection of the behavioral end-point; repeated testing does not contribute to the development of the observed hyperalgesia. Carrageenan-induced inflammation resulted in significantly shorter paw withdrawal latencies as compared to saline-treated paws and these latency changes corresponded to a decreased thermal nociceptive threshold. Both the thermal method and the Randall-Selitto mechanical method detected dose-related hyperalgesia and its blockade by either morphine or indomethacin. However, the thermal method showed greater bioassay sensitivity and allowed for the measurement of other behavioral parameters in addition to the nociceptive threshold.

Animals↗

PubMed1988

Detection of nucleic acid hybridization by nonradiative fluorescence resonance energy transfer.

Three approaches were used to study hybridization of complementary oligodeoxynucleotides by nonradiative fluorescence resonance energy transfer. (i) Fluorescein (donor) and rhodamine (acceptor) were covalently attached to the 5' ends of complementary oligodeoxynucleotides of various lengths. Upon hybridization of the complementary oligodeoxynucleotides, energy transfer was detected by both a decrease in fluorescein emission intensity and an enhancement in rhodamine emission intensity. In all cases, fluorescein emission intensity was quenched by about 26% in the presence of unlabeled complement. Transfer efficiency at 5 degrees C decreased from 0.50 to 0.22 to 0.04 as the distance between donor and acceptor fluorophores in the hybrid increased from 8 to 12 to 16 nucleotides. Modeling of these hybrids as double helices showed that transfer efficiency decreased as the reciprocal of the sixth power of the donor-acceptor separation R, as predicted by theory with a corresponding R0 of 49 A. (ii) Fluorescence resonance energy transfer was used to study hybridization of two fluorophore-labeled oligonucleotides to a longer, unlabeled oligodeoxynucleotide. Two 12-mers were prepared that were complementary to two adjacent sequences separated by four bases on a 29-mer. The adjacent 5' and 3' ends of the two 12-mers labeled with fluorescein and rhodamine exhibited a transfer efficiency of approximately 0.60 at 5 degrees C when they both hybridized to the unlabeled 29-mer. (iii) An intercalating dye, acridine orange, was used as the donor fluorophore to a single rhodamine covalently attached to the 5' end of one oligodeoxynucleotide in a 12-base-pair hybrid. Under these conditions, the transfer efficiency was approximately 0.47 at 5 degrees C. These results establish that fluorescence modulation and nonradiative fluorescence resonance energy transfer can detect nucleic acid hybridization in solution. These techniques, with further development, may also prove useful for detecting and quantifying nucleic acid hybridization in living cells.

Chromatography, High Pressure Liquid↗

PubMed1988

Potentiation of neuromuscular blocking agents by calcium channel blockers in rats.

The effect of calcium channel blockers (Ca-antagonists) on the potency and reversibility of muscle relaxants (MR) was investigated in the in vitro phrenic nerve-hemidiaphragm and in vivo sciatic nerve-tibialis anterior preparation of rats. To increase the relevance of the experimental findings to the clinical situation, the [Ca++] and [Mg++] in vitro were the same as in the plasma of rats and humans and the stimulation parameters used in vitro and in vivo were similar to those that elicit voluntary movements of the muscles used. Both verapamil and nifedipine significantly decreased the I50 and I90 of d-tubocurarine (d-Tc), pancuronium, vecuronium, and atracurium in vitro and those of the first three MR in vivo (P less than 0.001). In vitro, the depression of the force of contraction of the diaphragm (P) caused by all the Ca-antagonist-MR combinations could be reversed only partially by washout, neostigmine, or 4-aminopyridine. In vivo, because of limitations imposed by their cardiovascular depressant effect, the muscles were exposed to lower concentrations of Ca-antagonists for shorter periods. Under these circumstances the decrease of P caused by all Ca-antagonist-MR combinations recovered spontaneously close to control levels. This study indicates that acute administration of verapamil during anesthesia may increase MR potency, but it is unlikely that spontaneous recovery or reversibility of the residual neuromuscular (NM) block at the end of anesthesia will be significantly affected. However, long-term administration of Ca-antagonists may make difficult the reversal of the residual NM block.

Anesthesia↗

PubMed1987

Norethisterone contraceptive microspheres.

Two formulations of polylactic and polyglycolic acid microcapsules containing 75 and 100 mg of NET respectively were studied for a 90-day period of anticipated contraceptive effect in two groups of five women. A 200 mg dose of NET preparation was also studied for a 180-day period of anticipated contraceptive effect in 19 women. Alteration in menstrual cycle, with tendency to short bleeding episodes, spotting days, and amenorrhea were the most important collateral effects. In the majority of cases, ovulation was inhibited. No cases of pregnancy were presented. The obtained NET circulating levels were very stable during the period of anticipated contraceptive effect.

Contraception↗

PubMed1987

Chronic effects of an alpha-glucosidase inhibitor (Bay o 1248) on intestinal disaccharidase activity in normal and diabetic mice.

Bay o 1248 is a potent alpha-glycosidase inhibitor that reduces postprandial hyperglycemia when administered p.o. with sucrose or maltose. The compound binds to and competitively inhibits the alpha-disaccharidases and is also readily absorbed across the intestinal mucosa. To evaluate its effect on the activity of disaccharidases and on metabolic control, groups of obese diabetic mice (C57BLKsJ db/db) were given the drug for periods of 3, 7 and 84 days as a drug food mixture (5 or 10 mg/100 g of food). Nondiabetic mice of the same strain were dosed for 3 and 7 days. The drug did not influence body growth, food intake or fasting blood glucose. However, urine glucose excretion was significantly decreased at the higher dose in the diabetic mice. The drug had no effect on the protein content of jejunum (proximal and middle thirds) or ileum (distal third) of the small intestine. The activity of sucrase and maltase was significantly decreased in practically all segments of the small intestine in both diabetic and nondiabetic mice. These changes were evident after 3 days of drug administration. Lactase was not affected by the drug. The mechanism underlying these changes, although unclear, is of significant interest and deserves further investigation.

1-Deoxynojirimycin↗

PubMed1986

The effect of age, gender, and sexual maturation on the caffeine breath test.

This study demonstrated the feasibility of utilizing the (3-13C-methyl) caffeine breath test (CBT) in children and adolescents, and examined the effect of gender, age, and puberty on the CBT. The CBT, expressed as the 2-hour accumulative exhalation of labeled CO2 (2-hour CO2), was compared to the CBT results in the adult. The 2-hour CO2 values were higher in the children than the adult, and the decrease in the CO2 values occurred in males during late puberty and in females during early puberty.

Adolescent↗

PubMed1985

A Tn3 lacZ transposon for the random generation of beta-galactosidase gene fusions: application to the analysis of gene expression in Agrobacterium.

The construction and use of a Tn3-lac transposon, Tn3-HoHo1, is described. Tn3-HoHo1 can serve as a transposon mutagen and provides a new and useful system for the random generation of both transcriptional and translational lacZ gene fusions. In these fusions the production of beta-galactosidase, the lacZ gene product, is placed under the control of the gene into which Tn3-HoHo1 has inserted. The expression of the gene can thus be analyzed by monitoring beta-galactosidase activity. Tn3-HoHo1 carries a non-functional transposase gene; consequently, it can transpose only if transposase activity is supplied in trans, and is stable in the absence of this activity. A system for the insertion of Tn3-HoHo1 into sequences specifically contained within plasmids is described. The applicability of Tn3-HoHo1 was demonstrated studying three functional regions of the Agrobacterium tumefaciens A6 Ti plasmid. These regions code for octopine catabolism, virulence and plant tumor phenotype. The regulated expression of genes contained within each of these regions was analyzed in Agrobacterium employing Tn3-HoHo1 generated lac fusions.

Amino Acid Sequence↗

PubMed1985

The effect of verapamil and EGTA on the rat phrenic nerve-hemidiaphragm preparation.

Relatively high concentrations of verapamil or EGTA [ethylene glycol-bis (beta-aminoethyl ether) N, N, N',N'-tetra acetic acid] inhibit contraction (P) of the rat phrenic nerve-hemidiaphragm preparation elicited by direct or indirect stimulation. The inhibitory effect of verapamil is greater (P less than 0.002) with direct (I50 = 26.3 +/- 1.7 microM) than indirect = I50 = 37.6 +/- 1.9 microM) stimulation. For EGTA the reverse is true: I50 is 1320 +/- 80 microM with direct and 1100 +/- 60 microM with indirect stimulation. The greater than 90% verapamil-induced depression of P can only be partially reversed by washout. Increasing the [Ca2+] or the addition of 4-aminopyridine (4AP) has insignificant antagonist effect. Except for the antagonism by 4AP during direct stimulation, the EGTA-induced depression of P is better antagonized by washout, increase of the [Ca2+], or the addition of 4AP than that caused by verapamil. Neostigmine did not antagonize the depression of P caused by either verapamil or EGTA. The findings presented indicate that the primary site of action of verapamil is postjunctional and that of EGTA is prejunctional.

4-Aminopyridine↗

PubMed1985

[Drug metabolism in the septic liver: conclusions about the pharmacokinetics of chloramphenicol].

In nine patients in anaerobic septic shock, five of them with hepatic injury compatible with sepsis liver failure, hematic chloramphenicol concentration was determined at 5 minutes, 1, 2, 3 and 6 hours after intravenous administration of the first of three daily dose (50 mg/k/day); in the hepatic failure group the procedure was repeated with the next dose, previous attempt of haemodynamic compensation with two hours dopamine (3-10 mcg/k/min.) infusion. Starting from experimental data computation adjustment of time-concentration curve and lineal regression with a p = 0.0001 adjustment was done, determining half live (HL), distribution volume (DV), constant of elimination (K) and clearance (CL). In septic shock without hepatic injury patient group, there was noticed a uniform behavior in time-concentration graphic, withdrawn from chloramphenicol bone-marrow depression levels and pharmacokinetics parameters quite near the normal ones, with a reasonable extension of (DV). When attempting hepatic injury patient group, though an individual variability, drug concentration reach bone marrow depression levels and there was a significant lowering of Cl (p = 0.001) and a reasonable one of DV. Dopamine haemodynamic compensation attempt results in an increase of chloramphenicol hematic concentration in the sepsis liver group and the pharmacokinetics levels bear new deterioration. Practical meaning of the methodology used in drug handling in severe hepatic failure is stressed, to allow mathematic valuation of different pathogenic compounds. Though each patient should be individually evaluated, in septic shock without liver injury chloramphenicol dosification should not been any changes but in presence of sepsis liver doses should be diminished to half and administration interval extended to 11.5 hours.

Chloramphenicol↗

PubMed1984

Nucleotide sequence of the tms genes of the pTiA6NC octopine Ti plasmid: two gene products involved in plant tumorigenesis.

The nucleotide sequence of the tumor morphology locus, tms, from pTiA6NC has been determined. The sequence analysis indicates that each of two polyadenylylated transcripts encoded by this locus contains an open reading frame; the predicted transcript 1 gene product has a molecular size of 83,769 daltons, and the predicted transcript 2 gene product, of 49,588 daltons. The precise start and stop positions of the transcript 2 RNA have been mapped with S1 nuclease. Several insertion mutations have been constructed. One of these localizes the transcript 2 promoter within the 72 base pairs 5' to transcription initiation. Significant homology was observed between the protein encoded by transcript 1 and the adenine binding region of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens, suggesting that the transcript 1 protein binds adenine either as substrate or cofactor.

Amino Acid Sequence↗

PubMed1984

Nucleotide sequence and transcript mapping of the tmr gene of the pTiA6NC octopine Ti-plasmid: a bacterial gene involved in plant tumorigenesis.

The nucleotide sequence of a tumor morphology gene, tmr, from the Agrobacterium tumefaciens Ti-plasmid, pTiA6NC, and its flanking 5' region was determined by M13 "dideoxy" procedures. The DNA sequence reveals an open reading frame capable of encoding a 240 amino acid protein. We have identified the polyadenylated transcript initiation and termination sits by S1 nuclease mapping. The extent of the sequence required for transcription 5' to the start of transcription has been delimited by two transposon insertions. The first of these maps at -- 121 with respect to transcription initiation and results in the wild-type phenotype, the second insertion maps at about -85 and results in a tmr phenotype.

Arginine↗

PubMed1984

The use of biodegradable norethisterone implants as a 6-month contraceptive system.

The effects of a 6-month contraceptive system of biodegradable norethisterone (NET) implants on the menstrual cycle, estradiol and progesterone levels, the presence of side effects, its contraceptive effectiveness, and the NET levels achieved were studied in a group of nine women. There was practically no disruption of the menstrual cycle and no important side effects. Ovulation was inhibited in four subjects, and another four subjects remained ovulatory. In all the subjects a cyclic secretion of estradiol was maintained. No pregnancies occurred. The circulatory levels of NET were very stable throughout the 6-month period of implant use.

Adult↗

PubMed1982

[Massive aortic thrombosis of newborn. One case (author's transl)].

The authors report a case of aortic massive thrombosis complicating dehydration and neonatal infection in a 30 days old boy. This thrombosis seems have began in ductus arteriosus. Discussion of etio-pathogenesis of such aortic thrombosis is based upon literature review.

Aorta, Thoracic↗