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Biomedical subjects

R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 127 records · Page 7Linked to original sources
PubMed1995

Sudden cardiac death and polymorphous ventricular tachycardia in patients with normal QT intervals and normal systolic cardiac function.

This study delineates the clinical spectrum of 15 patients with polymorphic ventricular tachycardia and normal QT intervals in the absence of apparent structural heart disease, adverse drug effects, or electrolyte disturbances. Patients presented with either palpitations (n = 2), presyncope (n = 5), syncope (n = 4), no symptoms (n = 1), or aborted sudden death (n = 3). Mean age was 41 years (range 20 to 64), and mean follow-up 38 months (range 4 to 109). Left ventricular function was normal as determined by either echocardiogram (n = 9) or left ventriculography (n = 9). Episodes of polymorphic ventricular tachycardia (VT) were analyzed in terms of the preceding interval, and the relation of the initiating coupling interval to the QT interval (coupling interval/QT interval = polymorphic VT index). The mean QT for the group as a whole was 0.41 +/- 0.02 second. Patients could be separated into 3 distinct groups. Four patients had polymorphic VT reproducibly induced by exercise and initiated by late-coupled beats (mean polymorphic VT index 1.27 +/- 0.21). Isoproterenol induced polymorphic VT in 3 of 4 patients, and all 4 responded to chronic beta blockade. Two patients had polymorphic VT during episodes of coronary artery spasm, and both responded to calcium channel blockade. Polymorphic VT unrelated to exertion or coronary vasospasm occurred in 9 patients. Tachycardia onset was initiated by closely coupled beats (mean polymorphic VT index 0.95 +/- 0.16), and was preceded by a pause in 4 patients, and no pause in 5 patients. Sudden death occurred in 5 of 9 patients with the shortest polymorphic VT indexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Circulating alpha-actin in non-insulin-dependent diabetics with autonomic dysfunction.

Silent myocardial ischemia in non-insulin-dependent diabetic patients occurs frequently in association with autonomic dysfunction, suggesting that diabetic neuropathy may be involved in the development of this disorder. Repeated episodes of silent myocardial ischemia can induce myocardial necrosis. Recently, actin was detected with Western blotting in the serum of patients with acute myocardial infarction and angina pectoris. We found that a large proportion of non-insulin-dependent diabetic patients with neuropathy also have detectable circulating concentrations of alpha-actin, and therefore suggest that the determination by immunoblotting of serum alpha-actin in such patients is an effective method to detect myocardial cell suffering and to identify patients that may need special consideration.

Actins↗
PubMed1995

Seromuscular colocystoplasty lined with urothelium: experience with 16 patients.

OBJECTIVES: Report of initial clinical experience with seromuscular colocystoplasty lined with urothelium (SCLU), a new operation to increase bladder capacity and compliance without incorporating intestinal mucosa into the urinary tract. We have previously reported the technique and results of this procedure in a canine model. METHODS: Sixteen patients underwent SCLU at two institutions. Their charts were reviewed retrospectively. The patients have been observed for a mean of 12 months. RESULTS: Postoperatively, the bladder capacity increased an average of 2.4-fold from a mean of 139 mL (+/- 23.7 SEM) to 335 mL (+/- 38.9 SEM) in 14 patients (P < 0.001). Two patients required reaugmentation. Preoperative and postoperative bladder end filling pressures were available in 13 patients and decreased from a mean of 51.6 cm H2O (+/- 4.2 SEM) to 27.7 cm H2O (+/- 2.4 SEM) (P < 0.001). Of the 16 patients, 13 were incontinent preoperatively; 5 had renal insufficiency. Three patients have undergone renal transplantation following SCLU. After SCLU, 13 patients were dry day and night, 1 incontinent at night only, and 2 remained incontinent. Ten patients have undergone postoperative bladder biopsy. Seven demonstrate urothelium covering the augmented portion of the bladder, 2 have regrowth of colonic mucosa, and 1 shows a mixture of colonic mucosa and urothelium. CONCLUSIONS: The results presented suggest that SCLU is a viable alternative to the more conventional forms of bladder augmentation in selected patients.

Adolescent↗
PubMed1995

Phase II trial of piritrexim and DTIC using an alternating dose schedule in metastatic melanoma.

A Phase II trial was conducted in patients with metastatic malignant melanoma with DTIC 250 mg/m2 intravenously for 5 days alternating monthly with Piritrexim (PTX) using an intermittent, low-dose oral administration schedule. PTX was administered at a starting dose of 25 mg orally three times per day for 5 days weekly for 3 weeks followed by 1 week of rest. Twenty-one patients were entered into the study. Among the 17 patients assessable for response, 1 patient had a minor response, and 3 patients had stable disease. No partial or complete response were observed. Toxicity was tolerable and consistent mainly of myelosuppression. Using this alternating dose schedule, PTX and DTIC produced little response in metastatic melanoma.

Administration, Oral↗
PubMed1995

Endoscopic intrasphincteric injection of botulinum toxin for the treatment of achalasia.

Three patients with achalasia were treated with endoscopic injection of botulinum toxin (BoTx). BoTx (80 U) was injected via a sclerotherapy needle into the lower esophageal sphincter (LES). One patient complained of transient heartburn that resolved after omeprazole treatment. Two patients reported sustained symptomatic improvement. They were able to eat normally 48 h after treatment and have remained symptom free for 5 and 6.5 months, respectively. In these patients, esophageal manometry 4 months after treatment showed a marked reduction of resting LES pressure and the appearance of a previously absent LES relaxation after swallowing. The third patient had only a transient clinical improvement, with occasional dysphagia beginning 3 months after treatment. All patients showed unchanged aperistalsis of the esophageal body. Its less invasive nature compared with other therapeutic alternatives may give BoTX injection a role in the treatment of some patients with achalasia.

Adult↗
PubMed1995

Functional evaluation of the results of hypospadias surgery with uroflowmetry.

To determine the role of uroflowmetry in the evaluation of the functional results of hypospadias repair we retrospectively reviewed the records of 32 patients who underwent hypospadias repair with urethral reconstruction (mean age 2.4 years and mean followup 3.6 years). Patients with a plateau pattern and a maximum flow rate 2 standard deviations below the mean for age, body surface and voided volume on more than 1 determination were considered to have urethral obstruction. Urethroplasty had been performed with a meatal based flap in 11 cases, an onlay preputial flap in 5 and a tubularized preputial island flap in 16. Two of 11 patients with a meatal based flap, 5 of 16 with a tubularized preputial island flap and none with an onlay preputial flap had uroflow evidence of urethral stenosis. The 2 patients in the meatal based flap group responded to dilation with a normal flow. Of the tubularized preputial island flap group 3 patients required urethroplasty to correct a stricture and 2 had improvement with dilation alone. Three patients in the tubularized preputial island flap group had normal flow after treatment and 2 had improvement. Only 2 of the 7 patients with strictures were symptomatic. We conclude that uroflow examination is an important noninvasive tool to evaluate the functional results of urethroplasty in children and detect asymptomatic strictures.

Child↗
PubMed1995

Potential dangers of oxygen supplementation during facial surgery.

The use of local anesthesia and intravenous sedation has made same-day outpatient surgery a viable option for many aesthetic and reconstructive procedures. These procedures often include the use of supplemental oxygen. Oxygen-enriched environments increase the combustibility of most materials, and "oxygen pooling" has been suspected to play an integral role in intraoperative fires. A personal experience with an intraoperative explosion and fire during a cosmetic blepharoplasty compelled us to explore the potential danger inherent in the use of supplemental oxygen as well as potential strategies to minimize that danger. This study systematically examines the microenvironment created by the use of oxygen both in the operative field and beneath the surgical drapes under conditions simulating routine facial surgery and various recommended modifications of its delivery. With the use of oxygen supplementation, oxygen concentration beneath the drapes was found to be consistently elevated when compared with ambient air (20.9 percent) and reached levels as high as 53.5 percent. Oxygen concentration in the operative environment was mildly but not significantly elevated. Although criteria for the use of oxygen supplementation are not clear, when administration is deemed necessary, the use of a posterior pharyngeal catheter for its delivery had no advantage over nasal prongs. However, appropriate alternatives include the use of "open face" draping techniques, the use of compressed air beneath the drapes as a substitute for oxygen supplementation in unsedated patients, and cessation of oxygen supplementation for 60 seconds prior to the use of a possible ignition source with oxygen flow rates of less than 3 liters per minute.

Accidents↗
PubMed1995

The bgl1 gene of Trichoderma reesei QM 9414 encodes an extracellular, cellulose-inducible beta-glucosidase involved in cellulase induction by sophorose.

We have investigated the effect of disruption of the bgl1-(beta-glucosidase l-encoding) gene of Trichoderma reesei on the formation of other beta-glucosidase activities and on the induction of cellulases. To this end the bgl1 locus was disrupted by insertion of the Aspergillus nidulans amdS (acetamidase-encoding) gene. The bgl1-disrupted strain did not produce the 75 kDa extracellular beta-glucosidase on cellulose or lactose, but still formed beta-glucosidase activity on glucose, cellobiose, xylan or beta-1,3-glucan, suggesting that the enzyme(s) exhibiting this beta-glucosidase activity is (are) not encoded by bgl1. The cellulase-inducer sophorose induced the bgl1-encoded beta-glucosidase, whereas the remaining beta-glucosidase activity was induced by methyl-beta-D-glucoside. The bgl1-gene product was mainly secreted into the medium, whereas the other beta-glucosidase activity was mainly associated with the cells. A bgl1-multicopy strain formed higher amounts of cellulases than the parent strain. Nonsaturating concentrations of sophorose efficiently induced cellobiohydrolase l formation in the bgl1-multicopy strain, but less efficiently in the bgl1-disrupted strain. The multicopy strain and the parent strain were comparably efficient at saturating sophorose concentrations. The beta-glucosidase inhibitor nojirimycin strongly inhibited induction in all strains. These data suggest that the bgl1-encoded beta-glucosidase is not identical to the plasma-membrane-bound, constitutive, methyl-beta-glucoside inducible beta-glucosidase, but represents an extracellular cellulose-induced enzyme. Both enzymes contribute to rapid induction of cellulases by modifying the inducer sophorose.

Base Sequence↗
PubMed1995

Gentamicin formation in Micromonospora purpurea: stimulatory effect of ammonium.

The effect of ammonium on the fermentative production of gentamicin in Micromonospora purpurea has been studied using a chemically defined medium. Ammonium chloride concentrations ranging from 20 to 150 mM resulted in a proportional stimulation of growth and antibiotic formation. The use of other ammonium salts exerted a similar effect. Among the products of ammonium assimilation, glutamate and glutamine were able to exert the stimulatory effect. In addition, both amino acids reproduced the stimulation in resting cell systems of this microorganism and this result was not modified by the presence of chloramphenicol, eliminating a possible inductive action as the cause of this effect. The use of a glutamine synthetase inhibitor prevented antibiotic formation. This inhibition was reverted only by glutamine, suggesting that this amino acid was responsible of ammonium stimulation. Glutamine stimulation seems to be due to its ability to produce 2-deoxystreptamine and glucosamine, intermediates of the gentamicin biosynthetic pathway.

Ammonium Chloride↗
PubMed1995

Pyeloplasty improves renal function and somatic growth in children with ureteropelvic junction obstruction.

We studied the systemic effects of pyeloplasty in 38 children with unilateral ureteropelvic junction obstruction. Mean patient age at surgery was 2.5 years and 22 patients were age 1 year or younger. Mean followup was 18 months. We recorded serum creatinine levels, glomerular filtration rate calculated by the Schwartz formula body growth, the degree of dilatation and the excretory curve of the diuresis renogram. Pyeloplasty was effective in decreasing the degree of ultrasonographic dilatation and the excretory curve of the renogram in 36 cases. Two patients required reoperation. Individual renal function improved significantly in children younger than 1 year with preoperative differential function less than 45% but not in older children. Serum creatinine level decreased significantly after pyeloplasty in all children. Likewise, glomerular filtration rate improved significantly in all children. Preoperatively, 72% of children younger than 1 year were below the 50th percentile in height. The distribution of heights became normal after surgery. Overall, percentile rank for height increased in a significant number of patients of all ages. We conclude that unilateral hydronephrosis systemically affects body growth and overall renal function, the salutary effect of pyeloplasty goes beyond the affected kidney and pyeloplasty may be of greater benefit when performed in infancy. These parameters must be considered in protocols designed to compare outcomes in children with hydronephrosis treated surgically with those who are simply observed.

Body Height↗
PubMed1995

Cardiovascular magnetic resonance imaging goes beyond anatomy.

Magnetic resonance imaging (MRI) provides noninvasive functional information as well as a three-dimensional anatomic display of the cardiovascular system. MRI of protons, phosphorus, or sodium nuclei is currently being investigated to characterize cardiovascular pathology, and the potential benefits of paramagnetic contrast agents are becoming apparent. Finally, techniques to quantitate blood flow, vascular pressures, chamber volumes, ventricular ejection fractions, and cardiac output are being developed.

Contrast Media↗
PubMed1994

Amniotic fluid prostanoid concentrations increase early during the course of spontaneous labor at term.

OBJECTIVE: The purpose of this study was to determine whether amniotic fluid concentrations of prostanoids increase during spontaneous labor at term. STUDY DESIGN: Amniotic fluid was retrieved transabdominally from 168 patients in spontaneous labor and from 82 patients not in labor. Prostaglandin E2, prostaglandin F2 alpha, 13, 14-dihydro-15-keto-prostaglandin F2 alpha, thromboxane B2, and 6-keto-prostaglandin F1 alpha concentrations were measured with sensitive and specific radioimmunoassays previously validated for amniotic fluid. Statistical analysis was conducted with Kruskal-Wallis analysis of variance, followed by Dunn's test for multiple comparisons. RESULTS: (1) Amniotic fluid concentrations of all prostanoids were significantly higher in patients in early labor (cervical dilatation of < or = 3 cm) than in patients not in labor. (2) The magnitude of the increase in amniotic fluid prostanoid concentrations during early labor was significantly greater for prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha than for prostaglandin E2, thromboxane B2, and 6-keto-prostaglandin F1 alpha. (3) Patients in the active phase of labor with cervical dilatations between 4 and 7 cm did not have higher prostanoid concentrations than those in early labor (cervical dilatation of < or = 3 cm). (4) A significant increase in amniotic fluid concentrations of prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha was found in patients with advanced cervical dilatation (8 to 10 cm) in comparison with those in early labor (< 3 cm). CONCLUSION: Amniotic fluid prostanoid concentrations increase early during the course of spontaneous labor at term.

Amniotic Fluid↗
PubMed1994

Stimulation of phosphoinositide hydrolysis by glyceraldehyde-3-phosphate in electroporated HIT-T15 cells.

HIT-T15 cells labeled with myo-[3H] inositol were permeabilized by electroporation and subsequently stimulated with various glycolytic intermediates in the presence of 20 mM LiCl in a buffer mimicking cytosolic ionic composition. Of the various glycolytic intermediates tested, only D-glyceraldehyde-3-phosphate (G3-P) stimulated the formation of labeled inositol phosphates. The half-maximal response to G3-P occurred at a concentration of 0.75 mM. Formation of inositol phosphates in electroporated cells was also observed in response to GTP. G3-P further potentiated the formation of inositol phosphates in response to GTP, however, the interaction between G3-P and GTP was additive rather than synergistic, indicating that G3-P stimulates phosphoinositide hydrolysis in a manner different than the receptor mediated GTP-dependent activation of phospholipase C. The potentiation of the GTP response by G3-P did not appear to involve inhibition of the GTPase activity of a phosphoinositide-specific G protein, since G3-P also potentiated the formation of inositol phosphates in response to GTP-gamma-S or NaF in a nearly additive manner.

Analysis of Variance↗
PubMed1994

Malignant melanoma: from subcutaneous nodule to brain metastasis.

A thirteen-year-old patient, diagnosed with melanoma was followed cytogenetically using short-term cultures of specimens from a subcutaneous nodule, lymph node, and brain metastases. Simple hypodiploid karyotypes with loss of heterozygosity for chromosomes 5, 9, 10, 16 and 17 and two structural changes in 3 and between 13 and 21 increased in complexity to near triploid in the lymph node. Two cell types of the lymph node showed a progression of structural rearrangements prior to metastasis to the brain. Translocation of 6p to chromosome 2, deletions of 8, and a translocation (2;19) preceded p and q arm deletions of both chromosomes 9 and 11 in the lymph node. Cells metastasizing to the brain showed the accumulation of all previous aberrations and had acquired a direct duplication of distal 17 long arm. Whether or not elevated levels of protein kinase C, located on chromosome 17q contribute to tumor adhesion and growth on the brain remains to be elucidated. Identification of most chromosomes undergoing rearrangement was carried out using whole chromosome painting probes in in situ hybridizations. Some of these rearrangements would have been impossible to identify by standard karyotyping.

Aneuploidy↗