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J Figueroa

Publications and source records attributed to J Figueroa.

At least 73 records · Page 4Linked to original sources
PubMed1989

The major component of the rat sperm fibrous sheath is a phosphoprotein.

The fibrous sheath from rat epididymal sperm was isolated by sequential extraction, first with Triton X-100 and dithiothreitol, and then with 6 M urea and dithiothreitol. The latter extraction procedure solubilized most of the sperm components, leaving the head and the fibrous sheath as the only intact structures. This material was purified by sucrose gradient centrifugation. Electron microscopy confirmed the purity of the isolated material and revealed the characteristic structural features of the fibrous sheath. Polyacrylamide gel electrophoresis (in the presence of sodium dodecyl sulfate) of the fibrillar material, showed a complex polypeptide composition. The polypeptides with molecular weights of 80,000, 24,000, and 11,500 accounted for about 65% of the total protein of the fibrous sheath. Peptide map analyses indicated that the components of molecular weights of 80,000 and 24,000 are unrelated to the polypeptides of similar size of the outer dense fibers. On the other hand, it appears that the fibrous sheath and the outer dense fibers share the polypeptide of 11,500 daltons. The component of 80,000 daltons contains on the average about 3 mol of phosphoserine per mol of polypeptide, indicating that the most abundant polypeptide of the fibrous sheath is a phosphoprotein.

Amino Acids↗
PubMed1989

Intracellular distribution of poly(ADP-ribose) synthetase in rat spermatogenic cells.

The highest activity of poly(ADP-ribose) synthetase was found in the testis among several rat tissues tested. Subcellular fractionation of the testis demonstrated that the synthetase was localized primarily in the nucleus and partially in the microsomal-ribosomal fraction. This result was confirmed by immunocytochemical staining with the enzyme-specific antibody. The synthetase was localized in the nuclei of interstitial cells, Sertoli cells, spermatogonia, and spermatocytes. In addition, round spermatids showed a granular staining in the cytoplasm, which was comparable in intensity with that in the nucleus. The cytoplasmic synthetase had a molecular weight of 115,000 and synthesized oligomers of ADP-ribose on itself (automodification). The synthetase activity in the isolated cytoplasmic fraction was stimulated about threefold by the addition of DNA and depressed by treatment with DNase I, suggesting the presence of endogenous activator DNA. A candidate DNA for such an activator was isolated from the microsomal-ribosomal fraction, and identified tentatively as mitochondrial DNA on the basis of its size and restriction fragment patterns.

Animals↗
PubMed1989

Vasotocin and isotocin precursors from the white sucker, Catostomus commersoni: cloning and sequence analysis of the cDNAs.

The nucleotide sequences of cloned cDNAs encoding the precursors for vasotocin and isotocin have been elucidated by analyzing a lambda gt11 library constructed from poly(A)+ RNA from the hypothalamic region of the teleost fish Catostomus commersoni. Screening of the library was carried out with synthetic oligonucleotide probes deduced from the amino acid sequences of the nonapeptides vasotocin and isotocin. The cDNA nucleotide sequences predict isotocin and vasotocin prohormone precursors each consisting of a signal peptide, a hormone moiety, and a neurophysin-like molecule. However, in comparison to their mammalian counterparts, both fish neurophysins are extended at their C termini by an approximately 30 amino acid sequence with a leucine-rich core segment. These extensions show striking similarities with the glycopeptide moiety (the so-called copeptin) present in mammalian vasopressin precursors, except that they lack the consensus sequence for N-glycosylation. These data suggest that mammalian copeptin is derived from the C terminus of an ancestral neurophysin.

Amino Acid Sequence↗
PubMed1987

The effect of mild hypoxemia maintained for twenty-four hours on maternal and fetal glucose, lactate, cortisol, and arginine vasopressin in pregnant sheep at 122 to 139 days' gestation.

The effects of prolonged mild hypoxemia on the fetus have received little attention. We investigated the response to a decrease in fetal arterial Po2 of 5 mm Hg or less sustained for a period of 24 hours in the chronically instrumented fetal lamb. Hypoxemia was induced by an infusion of nitrogen via the maternal trachea for 24 hours in 13 pregnant sheep at 122 to 139 days' gestation. Two control periods of air infusion via the maternal trachea for 24 hours were alternated with hypoxemia. Fetal hypoxemia was not associated with any change in fetal pH. During the first and second exposures to hypoxemia, there was an increase in fetal plasma lactate of 22.8 +/- 22.3 and 15.3 +/- 14.6 mg.dl-1 (mean +/- SD) above preliminary values (p less than 0.05) compared with the control period. Fetal plasma cortisol also increased by 5.7 +/- 6.1 and 9.5 +/- 5.4 ng.ml-1 (mean +/- SD) (p less than 0.05) compared with the control period. These results suggest that the fetal lamb at 122 to 139 days' gestation is highly sensitive to small decrements in Po2 of 5 mm Hg or less.

Animals↗
PubMed1986

Effect of hydralazine on intrapulmonary shunt.

We compared the acute effects of bilateral arteriovenous may be related to levels of PvO2. The hydralazine-associated (p less than .05) decrease in resistance. Mixed venous oxygen fistulas to those of hydralazine infusion on hemodynamics and pulmonary gas exchange in dogs with pulmonary edema induced by administration of oleic acid. Oleic acid significantly (p less than .01) increased intrapulmonary shunt (Qsp/Qt) and pulmonary and systemic vascular resistance, and reduced cardiac output. Once the lesion stabilized, both opening the fistula and infusing hydralazine produced a similar and significant (p less than .01) increase in cardiac output, and a significant (p less than .05) decrease in resistance. Mixed venous oxygen tension (PvO2) closely followed the changes in cardiac output; however, PaO2 did not change. Qsp/Qt significantly (p less than .01) increased with the fistulas open and with hydralazine infusion. Closure of the fistulas or bleeding the animal at the end of the experiment reversed the changes in cardiac output and Qsp/Qt. The comparable increases in cardiac output and Qsp/Qt produced by opening the fistulas or infusing hydralazine may be related to levels of PvO2. The hydralazine-associated PvO2 increase indicates that this drug increased oxygen transport to the tissues even as Qsp/Qt became larger.

Animals↗
PubMed1986

Digoxin-like substance in term pregnancy, newborns, and renal failure.

Digoxin-like substance (DLS) is detected in pregnant women near term, newborns, and in patients with renal failure using RIAs for digoxin. We made "digoxin" measurements in such patients using three digoxin RIA kits (Nuclear Medical Laboratories (N), Clinical Assays (C), and Corning Magic (M]. At term mother DLS (micrograms/l digoxin) was 0-0.19 (N), 0.09-0.24 (C), 0.07-0.24 (M); cord blood DLS was 0.35-0.75 (N), 0.46-0.90 (C), 0.42-0.90 (M); infant DLS was 0.5-1.1 (N), 0.28-0.98 (C) and was not measured by M. DLS was detected at term in mothers and was essentially undetectable by 24 hr postdelivery. Cord levels fell in eight of ten infants to significantly lower levels by the second day of life. DLS in renal hemodialysis patients not receiving digoxin was 0.04-0.41 (N), 0.01-0.34 (C), 0.03-0.40 (M). While postdialysis levels by N tended to be lower than predialysis, they rose by C and M. Dilutions of cord blood yielded similar results by N, nonlinear decreases by C, and more nearly parallel decreases by M. In renal failure patients, dilutions yielded similar results by N and marked nonparallel results by M. Digoxin results obtained with immunoassays may be inaccurate in these patient populations. Digoxin immunoassays must be individually characterized as to the expected results.

Digoxin↗
PubMed1983

Poly(ADP-ribose) synthetase associated to cytoplasmic structures of meiotic cells.

An active poly(ADP-ribose) synthetase has been found to be associated to mitochondria of frog oocytes and of testis from various species. The enzyme was also found in association with the microsomal-ribosomes fraction of the testis. Both enzymes are strongly inhibited by nicotinamide, thymidine, and theophylline, and they synthesize oligomers of ADP-ribose of an average chain length of 2-6 residues. The apparent km for NAD+ of the mitochondrial enzyme is 22 micro M which contrasts with the corresponding value of the chromatin-bound enzyme, 210 micro M NAD+. Treatment of the isolated mitochondria with Triton X-100 revealed that the enzyme is associated to a polydisperse structure. The higher specific activity of the enzyme associated to mitochondria was found in testis of 20 to 30 days old rats. This development study suggest that the maximal activity of the enzyme is associated to mitochondria belonging to primary spermatocytes. Poly(ADP-ribose) synthetase was also found in association of the microsome-ribosome fraction of rat, mouse, carp, and bull testis. This activity is 20 to 30 times higher than in the same fraction of the liver. Contrary to the chromatin-bound enzyme, the microsome-ribosome enzyme activity is stimulated 3 to 4 times by DNA, but it is slightly inhibited by histone H1. The enzyme seems to be associated to ribonucleoproteins of a very polydisperse nature. The possible relationship of poly(ADP-ribose) synthetase with the intermitochondrial cement and with the chromatoid body will be discussed. These are very unique structures only present in germinal cells.

Animals↗
PubMed1981

The effects of targeting improvements in urine glucose on metabolic control in children with insulin dependent diabetes.

A treatment program designed to increase the percentage of negative urine tests was implemented using a multiple-baseline across groups design in a sample of 19 families of children with insulin dependent diabetes. The treatment involved instruction in insulin adjustment, decrease in intake of simple sugars and saturated fats, and increase in exercise, along with teaching the parents to support improvements in children's self-regulatory behaviors using a point economy and praise. New procedures designed to measure and reinforce adherence to the urine testing regimen were developed. Results showed significant increases in percentage of negative urines consistent with implementation of treatment across the three treatment groups, which were maintained over the follow-up period. Metabolic measures of control, including glycosylated hemoglobin and serum glucose did not show improvements even though the relationship between the percentage of negative urine tests and glycosylated hemoglobin was very high during treatment.

Behavior Therapy↗
PubMed1980

Zymosan-induced experimental hypersensitivity pneumonitis in rabbits.

An experimental model of hypersensitivity pneumonitis is presented. New Zealand white rabbits, previously immunized against yeast-derived zymosan, reacted to intratracheal challenge developing extensive pneumonitis. The lesions healed in a few weeks. Control animals challenged with inert particulate material (latex beads) or suspending fluid (PBS-Mg++) did not show pulmonary inflammation. Nonimmunized rabbits developed only transient pneumonitis after zymosan challenge. This reaction was clearly different from that seen in the group of immunized animals. The model reveals that biologically active substances such as zymosan, which is able to activate the alternate pathway of complement and mononuclear phagocytes, requires an active immune state in order to cause significant tissue damage. Isolated exposure to this kind of substance may not be sufficient to cause lung disease.

Alveolitis, Extrinsic Allergic↗
PubMed1977

Treatment of typhoid fever with fosfomycin alone and associated to chloramphenicol or ampicillin.

Treatment with fosfomycin alone and associated to subtherapeutic doses of chloramphenicol or of ampicillin, has been tried on 50 patients with typhoid fever and on four carriers of S. typhi in the Hospital del Rey. 15 patients were treated with fosfomycin alone, 22 with fosfomycin plus chloramphenicol and 13 with fosfomycin plus ampicillin. The treatment lasted 15-20 days. The results have been evaluated clinically and bacteriologically, haemo- and coprocultures being carried out. The sensitivity of the isolated germs has been studied, including MIC and the synergism in vitro between fosfomycin-chloramphenicol and fosfomycin-ampicillin. Fosfomycin, chloramphenicol and ampicillin determinations have been carried out on the blood. The cures obtained were 67, 82 and 92% respectively with fosfomycin, fosfomycin-chloramphenicol and fosfomycin-ampicillin. We believe that this antibiotic can be useful in the treatment of typhoid fever, associating it to chloramphenicol or ampicillin, due to the synergism existing between them and given the results we have obtained.

Administration, Oral↗
PubMedDate not supplied

Preparation of monoclonal antibodies that differentiate between Histoplasma capsulatum variant capsulatum and H. capsulatum variant duboisii.

The immunosuppressive drug cyclophosphamide was used to facilitate the production of monoclonal antibodies (Mabs) which differentiated between the yeast phase of the two variants of the dimorphic fungus Histoplasma capsulatum by both enzyme-linked immunosorbent assay and Western blot. Two Mabs are described, identifying epitopes on a 70-75 kDa molecule, which are specific to H. capsulatum var. capsulatum and which do not identify epitopes of H. capsulatum var. duboisii. These Mabs have potential use in the epidemiology and serodiagnosis of histoplasmosis in areas where both classical and African forms of the disease occur.

Animals↗
PubMedDate not supplied

Murine monoclonal antibodies recognizing a non-capsular antigen that distinguishes between Cryptococcus neoformans var. neoformans and C. neoformans var. gattii.

A panel of 4 monoclonal antibodies (mabs) of the IgG1 subclass have been made against a cytoplasmic antigen of Cryptococcus neoformans. Mab 4E2 recognized isolates of C. neoformans var. gatti by enzyme-linked immunosorbent assay (ELISA), whilst the other antibodies did not recognize these antigens. By Western blot 4E2 recognized determinants at 110-125, 65-70, 45-50 and 36-38 kDa. Mabs 9E6, 7C7 and 5D9 recognized bands at 36-38 and approximately 30 kDa. All 4 mabs (4E2, 9E6, 7C7 and 5D9) recognized both non-encapsulated and encapsulated isolates of C. neoformans var. neoformans by ELISA, and in addition showed reactivity to only the cytoplasm and cell membrane of yeasts by immunofluorescence. Mab 7C7 recognized antigens of the closely related fungus Trichosporon beigelii by ELISA but did not recognize any other fungal antigens. The other 3 mabs showed no recognition of T. beigelii or any other fungal pathogens tested.

Animals↗
PubMedDate not supplied

Effects of enhanced conventional therapy on metabolic control in children with insulin-dependent diabetes mellitus.

We implemented a three-phase, 32-wk program to improve both self-regulation of adherence behaviors and insulin delivery in children with diabetes. Twenty children, aged 8-12 yr (mean duration 3.6 yr), enrolled. Phase 1 (wk 1-12) used behavior modification to improve diet, exercise, urine testing, and insulin adjustment, targeting an increased percentage negative urines. Feedback training and parent checks were used to improve reliability; adherence was measured using Clinitest placebos. Phase 2 (wk 13-20) was a stabilization period. Phase 3 (wk 21-32) studied the effect of insulin dose adjustment, comparing once-versus twice-daily shots in 10 pairs of children matched for %GHb. GHb, fasting plasma glucose, and lipids were measured at baseline and at the end of each phase. Results revealed a significant and sustained increase in negative urine tests, but no change in % GHb or FBG. Reliability of and adherence to urine tests were 83% and 76%, respectively. During phase 3, no significant differences were noted between groups receiving once- or twice-daily insulin injections. Thus, behavior modification resulted in increased reliability and adherence to routines, associated with a reliable increase in negative urines. This did not, however, produce changes in other control measures. Furthermore, no differences between those receiving 1 or 2 daily shots were evident.

Behavior Therapy↗