Biomedical subjects

J Salinas

Publications and source records attributed to J Salinas.

At least 73 records · Page 4Linked to original sources

PubMed1992

The distribution of 5-methylcytosine in the nuclear genome of plants.

We have determined the 5-methylcytosine (5mC) content in high molecular weight DNA, from two dicot (tobacco and pea) and two monocot (wheat and maize) plant species, fractionated according to base composition. The results show that the proportion of 5mC in the genomic fractions increases linearly with their guanine + cytosine (G + C) content while the proportion of non-methylated cytosine remains almost constant. This can be interpreted as a consequence of a difference in mutation pressure related to spontaneous deamination of 5mC to thymine between the different compartments of plant genomes.

5-Methylcytosine↗

PubMed1992

Two G-box-related sequences confer different expression patterns in transgenic tobacco.

We have analyzed the expression patterns conferred by two G-box-related motifs, a perfect palindromic sequence (PA, 5'-GCCACGTGGC-3') and motif I (Iwt, 5'-GTACGTGGCG-3'), in transgenic tobacco plants. A mutant version of motif I, Imu, was used as a negative control. PA is present in the promoters of several different genes, whereas Iwt is a conserved sequence found in abscisic acid-inducible promoters. Previously we have demonstrated that PA and Iwt, but not Imu, can bind to the tobacco transcription activator TAF-1 in vitro, with the PA sequence showing a 70-fold higher affinity as compared to Iwt. We found that tetramers of PA and Iwt, which differ by only 2 bp per 10-bp repeat, confer very different tissue-specific and expression patterns in transgenic tobacco plants. PA confers preferential expression in root tissues with a low level of activity in leaves, whereas Iwt directs developmentally regulated expression in seeds beginning 15 days after petals have fully expanded until seed maturation. Imu appears to be inactive because it gives the same expression pattern as the -90 cauliflower mosaic virus 35S promoter control. RNA gel blot analysis showed that the expression pattern of TAF-1 mRNA is similar to that directed by PA, suggesting that TAF-1 may be involved in the transcriptional regulation of PA.

Agrobacterium tumefaciens↗

PubMed1992

Importance of the active component of the detrusor muscle in bladder compliance.

An appropriate experimental study was designed and carried out in mongrel dogs, in order to evaluate the active muscle and cholinergic participation on bladder compliance. The filling bladder pressure was measured at 100 ml of bladder volume, in 50 dogs distributed into five groups of 10 dogs each: (1) control group, (2) group which received atropine (cholinergic antagonist), (3) group which received verapamil (extracellular Ca2+ blocker), (4) group which received nitroprusside (intracellular Ca2+ antagonist), and (5) group which received EGTA (Ca(2+)-chelating agent). Furthermore, the following was demonstrated. (1) The greatest decrease of the bladder filling pressure was observed in the group which was treated with EGTA. (2) A significant decrease of the bladder filling pressure was also seen in the group which was given nitroprusside. (3) The decrease of bladder filling pressure in the verapamil group tended towards statistical significance. (4) There was no decrease in the atropine group. Thus, it was concluded that the active muscle component has an important role in the bladder compliance (through the intracellular calcium fraction), and the cholinergic component does not participate in the bladder compliance.

Animals↗

PubMed1992

A study on the viscoelastic properties of the urinary bladder in dogs.

This experimental study was designed and carried out in order to investigate the participation of the collagen and muscular tissues on the viscoelastic properties of the bladder wall. Sixty-five adult male mongrel dogs were utilized. These animals were divided into 5 groups: control group (n = 10); dogs (n = 10) receiving 2.5 mg/kg atropine (cholinergic antagonist); dogs (n = 10) receiving 0.7 mg/kg verapamil (calcium extracellular inflow blocker); dogs (n = 10) receiving 0.1 mg/kg/min nitroprusside (intracellular calcium blocker), and dogs (n = 25) receiving EGTA (a calcium-chelating agent) at increasing doses from 90 to 450 mg/kg. Based on a mathematical model, we have demonstrated that: (1) the collagen component is responsible for the elastic properties; (2) the muscle component is responsible for the viscoelastic properties; (3) the viscoelastic properties have an active element which is affected by calcium total depletion, and (4) such viscoelastic properties are not dependent on cholinergic stimulation.

Animals↗

PubMed1992

[High pressure filling bladder].

A complete urodynamic study was carried out on 41 consecutive patients presenting in the cystomanometry a vesical filling pressure at maximum capacity higher than 30 cm H2O. Two groups were evident: group I with neurogenic etiology, and group II without an obvious neurogenic etiology. From its results it can be seen that a diminished vesical accommodation is not a urodynamic fact restricted to vesicourethral neurogenic dysfunction, but it happens in several non-neurogenic conditions. Within the neurogenic group, the urodynamic element most frequently associated to a diminished vesical accommodation was an inferior motor neuron-like vesicourethral dysfunction. An increased vesical filling pressure was not enough to produce urinary incontinence, being also necessary an added factor to prompt involuntary loss of urine.

Adolescent↗

PubMed1992

Induction chemotherapy with carboplatin and ftorafur in advanced head and neck cancer. A randomized study.

From 1987 to 1989, 42 patients with locally advanced squamous cell carcinoma of the head and neck (Stages III-IV, Mo) were randomized to receive radiotherapy (Group A) or three courses of induction chemotherapy followed by radiotherapy (Group B). There were 36 evaluable patients, 17 in Group A and 19 in Group B. The radiotherapy regimen was the same for both groups, 66-74 Gy total tumor doses with standard fractionation scheme of 2 Gy/day. The chemotherapy regimen was a combination of carboplatin 400 mg/m2 by intravenous bolus injection on day 1, and Ftorafur 1,000 mg/m2 orally once a day for 14 days. Cycles were given every 4 weeks. The complete response rate in Group A was 65%; in group B it was 31.5% after induction chemotherapy and 84% after radiotherapy. The 42-month actuarial overall survival rates were 34% for Group A and 47% for Group B (P = NS). Patients from both groups with a complete response had a significantly longer survival time than those with a partial response (P less than 0.001). No significant differences in disease-free survival were found between the two treated groups. The chemotherapy regimen was well tolerated, with moderate hematologic and gastrointestinal toxicity. Increased in radiation toxicity by chemotherapy was not observed.

Adult↗

PubMed1992

Placenta membranacea, previa and accreta. A case report.

A case of placenta membranacea, previa and accreta was managed conservatively and resulted in delivery of a mature fetus. The diagnosis of placenta membranacea and previa was obtained with ultrasound. The placenta previa and accreta necessitated a cesarean delivery and hysterectomy.

Adult↗

PubMed1992

[Carcinoma of the penis. Our experience with 22 cases].

The penis carcinoma is a neoplasia representing 0.7% of all male neoplasias, with an annual incidence between 1 and 2 cases per 100,000 inhabitants/year. The present study compiles the authors' experience in treating 22 patients presenting this neoplasia in the period between 1977-90. The procedures carried out included local resection, partial amputation, radical penectomy with lymphadenectomy plus radiotherapy, and palliative surgery plus radiotherapy all based on staging made following TNM grading. Therapy complications, follow-up, and survival results are explained. There were 5 occasions of spinocellular carcinoma co-existing with other neoplasias: 1 colon adenocarcinoma, 1 prostate carcinoma, 1 cleaved small cell centrocytic diffuse lymphoma, and 2 skin epithelioma in other sites, and relevant literature was reviewed. A background of psoriasis treated with psoralens plus UV was present in 4 cases, and caution was advised towards genital protection in patients undergoing UV radiations whether for therapeutic, recreational or cosmetic reasons.

Adult↗

PubMed1991

A tobacco bZip transcription activator (TAF-1) binds to a G-box-like motif conserved in plant genes.

Tobacco nuclear extract contains a factor that binds specifically to the motif I sequence (5'-GTACGTGGCG-3') conserved among rice rab genes and cotton lea genes. We isolated from a tobacco cDNA expression library, a partial cDNA clone encoding a truncated derivative of a protein designated as TAF-1. The truncated TAF-1 (Mr = 26,000) contains an acidic region at its N-terminus and a bZip motif at its C-terminus. Using a panel of motif I mutants as probes, we showed that the truncated TAF-1 and the tobacco nuclear factor for motif I have similar, it not identical, binding specificities. In particular, both show high-affinity binding to the perfect palindrome 5'-GCCACGTGGC-3' which is also known as the G-box motif. TAF-1 mRNA is highly expressed in root, but the level is at least 10 times lower in stem and leaf. Consistent with this observation, we found that a motif I tetramer, when fused to the -90 derivative of the CaMV 35S promoter, is inactive in leaf of transgenic tobacco. The activity, however, can be elevated by transient expression of the truncated TAF-1. We conclude from these results that TAF-1 can bind to the G-box and related motifs and that it functions as a transcription activator.

Amino Acid Sequence↗

PubMed1990

Gene distribution and isochore organization in the nuclear genome of plants.

The genomic distribution of 23 nuclear genes from three dicotyledons (pea, sunflower, tobacco) and five monocotyledons of the Gramineae family (barley, maize, rice, oat, wheat) was studied by localizing these genes in DNA fractions obtained by preparative centrifugation in Cs2SO4/BAMD density gradients. Each one of these genes (and of many other related genes and pseudogenes) was found to be located in DNA fragments (50-100 Kb in size) that were less than 1-2% GC apart from each other. This definitively demonstrates the existence of isochores in plant genomes, namely of compositionally homogeneous DNA regions at least 100-200 Kb in size. Moreover, the GC levels of the 23 coding sequences studied, of their first, second and third codon positions, and of the corresponding introns were found to be linearly correlated with the GC levels of the isochores harboring those genes. Compositional correlations displayed increasing slopes when going from second to first to third codon position with obvious effects on codon usage. Coding sequences for seed storage proteins and phytochrome of Gramineae deviate from the compositional correlations just described. Finally, CpG doublets of coding sequences were characterized by a shortage that decreased and vanished with increasing GC levels of the sequences. A number of these findings bear a striking similarity with results previously obtained for vertebrate genes.

Animals↗

PubMed1990

[Xanthogranulomatous pyelonephritis. Retrospective study].

The incidence of PGX in our setting is low (0.67%). Middle-aged women comprise most of our cases. This disease process is usually unilateral; 53.2% of the present series had right-sided renal involvement. Over the past 17 years, 135 cases of histopathologically-documented XGP have been recorded at our hospital. Sixty-three cases were studied retrospectively. Patient history, symptoms and signs, and data gleaned from physical examination are presented. Similarly, patient outstanding pathogenetic features are described. Preoperative diagnosis of XGP is difficult. The availability of high resolution imaging techniques has enhanced diagnostic accuracy. Urinary cytology permits preoperative diagnosis with an accuracy rate of 80%. The postoperative prognosis is excellent.

Aged↗

PubMed1990

[Treatment of bladder instability using intravaginal electric stimulation (intrarectal)].

Fourteen patients (13 females, 1 male) with urinary incontinence from bladder instability were treated with intravaginal (intrarectal) electrical stimulation. Good results were achieved in 57.1% of the cases. The foregoing finding shows that intravaginal (intrarectal) electrical stimulation may constitute a therapeutic option in urinary incontinence from bladder instability.

Adolescent↗

PubMed1989

The isochore organization and the compositional distribution of homologous coding sequences in the nuclear genome of plants.

The isochore structure of the nuclear genome of angiosperms described by Salinas et al. (1) was confirmed by using a different experimental approach, namely by showing that the levels of coding sequences from both dicots and Gramineae are linearly correlated with GC levels of the corresponding flanking sequences. The compositional distribution of homologous coding sequences from several orders of dicots and from Gramineae were also studied and shown to mimick the compositional distributions previously seen (1) for coding sequences in general, most coding sequences from Gramineae being much higher than those of the dicots explored. These differences were even stronger for third codon positions and led to striking codon usages for many coding sequences especially in the case of Gramineae.

Cell Nucleus↗

PubMed1989

Chromosome localization-dependent compositional bias of point mutations in Alu repetitive sequences.

The Alu repetitive sequence family originated from a common ancestor. Its members, apparently free from functional constraints, are interspersed throughout primate genomes. We have found that base substitutions occurring during the evolution of primates caused a decrease in the average G + C content of those members of the family that are located in an A + T-rich region of the genome. The family members that are located in a G + C-rich genomic region have not changed their, already high, G + C content. This suggests that the regional differences in G + C content, which are responsible for chromosomal banding, are caused by an accumulation of mutations that, although selectively neutral in the majority, show different compositional bias in different regions of the vertebrate chromosome.

Animals↗

PubMed1989

Fetal vascular responses to maternal nicardipine administration in the hypertensive ewe.

Calcium channel blockers such as nicardipine act as arterial vasodilators and are effective in the treatment of hypertension. Although they are also effective tocolytic agents, fetal effects have not been fully studied. Fifteen chronically catheterized near-term ewes were studied. Maternal and fetal cardiorespiratory parameters were measured in the control period and again 15 minutes after maternal venous infusion of angiotensin II. Nicardipine 20 micrograms/kg/min was given over 2 minutes and maternal and fetal cardiorespiratory parameters and fetal blood flow were measured 5.30 and 60 minutes later. Nicardipine reversed maternal hypertension and produced transient tachycardia. Fetuses responded initially with transient bradycardia and then developed hypercapnia and acidemia (p less than 0.03) by 60 minutes after nicardipine. Fetal placental blood flow decreased and vascular resistance increased by 5 minutes after nicardipine but returned toward control values after 30 minutes. Unexpectedly we observed the death of five fetuses by 65 minutes after nicardipine. We conclude that the administration of nicardipine in the hypertensive ewe results in significant alterations of fetal cardiorespiratory status and placental function that may lead to acidemia.

Angiotensin II↗

PubMed1989

Placental vascular responses to nicardipine in the hypertensive ewe.

Calcium channel blockers are arterial vasodilators effective in the treatment of hypertension. Therefore nicardipine, a dihydropyridine calcium channel blocker, should modulate angiotensin II-induced vasoconstriction. Regional blood flows were measured with radioactive microspheres in five chronically catheterized near-term ewes both before and 15 minutes after maternal infusion of angiotensin II at 5 micrograms/min. Nicardipine was then administered intravenously at 20 micrograms/kg/min over 2 minutes while the angiotensin II infusion was maintained. Blood flows were measured after 5 minutes. Maternal blood pressure levels were increased by angiotensin II from 83 +/- 4 mm Hg to 114 +/- 5 mm Hg, and were decreased to 70 +/- 4 mm Hg by nicardipine (p less than 0.05). Nicardipine also reversed angiotensin II-induced vasoconstriction in the renal and endomyometrial vascular beds (p less than 0.05). Unexpectedly, however, nicardipine worsened placental vasoconstriction caused by angiotensin II, as placental blood flow fell from 242 +/- 32 ml.min-1.kg-1 fetal weight to 128 +/- 7 ml.min-1.kg-1 fetal weight (p less than 0.05), and placental resistance increased from 0.48 +/- 0.04 mm Hg.ml-1.min.kg-1 fetal weight to 0.55 +/- 0.05 mm Hg.ml-1.min.kg-1 fetal weight (p less than 0.05). Nicardipine reverses angiotensin II-induced vasoconstriction systemically and in the kidney and uterus of the pregnant ewe, but does not reverse placental vasoconstriction and may significantly alter fetal cardiorespiratory status.

Angiotensin II↗

PubMed1989

[Participation of bladder dysfunction in urinary incontinence after prostatectomy].

Twenty-four patients with post-prostatectomy urinary incontinence were submitted to clinical and urodynamic evaluation. The clinical evaluation analyzed urinary symptoms and included rectal examination of the prostate lodge, neurourologic examination (perineal sensitivity, anal tone, bulbocavernous reflex, voluntary control of anal sphincter). The urodynamic study consisted of flowmetry, cystomanometry, detrusor pressure/micturition flow test and videocystography. An unstable bladder was demonstrated in 62.5% of the cases. Bladder dysfunction was recognized in 75% of the cases. Involvement of the striated periurethral sphincter was demonstrated in no patient. The clinical data did not provide orientation. No relation was observed between the urodynamic data, type of surgery, and amount of prostate removed. The urodynamic data appear to have a prognostic significance.

Aged↗

PubMed1989

[Dysfunction of the contractile capacity of the detrusor muscle in post-prostatectomy urinary retention].

We report on 23 consecutive patients with urinary retention following prostatectomy for benign prostatic hypertrophy. The patients were clinically and urodynamically evaluated. Urodynamic work-up included flowmetry, cystomanometry, detrusor pressure-micturition flow test, and videocystography. The involvement of detrusor contractility in urinary retention was observed in 60.87% of the cases and was ascribable to lower urinary tract obstruction in 39.19%. These data permitted instituting correct treatment.

Aged↗