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Biomedical subjects

R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 343 records · Page 19Linked to original sources
PubMed1983

Cholesterol accumulation in heterotransplanted renal cell cancer.

To date there have been no in vivo studies of the known propensity of human renal cell cancer (RCC) to accumulate large amounts of cholesterol. Caki-1, a human RCC line, was grown in the cheek pouches of immunosuppressed golden Syrian hamsters. Analysis of cholesterol levels revealed 2 to 4 times as much cholesterol in the heterotransplants as in any of the host tissues. After intraperitoneal injection of tumor-bearing hamsters with 4-14C-cholesterol, the tumors accumulated less radioactivity than did hamster liver and no more radioactivity than did hamster kidney or cheek pouch. It appears that accumulation of cholesterol by human RCC is not dependent on extensive uptake of extracellular cholesterol. Instead, an intrinsic defect in the cellular regulation of cholesterol synthesis and efflux is more likely to be responsible.

Adenocarcinoma↗
PubMed1983

Microsurgical vasovasostomy: an outpatient procedure under local anesthesia.

We performed microsurgical vasovasostomy on 25 outpatients using spermatic cord block anesthesia, an infrapubic incision and the 1 1/2-layer anastomosis technique. The average operating time was 2 hours 18 minutes and patients usually were discharged home after approximately 1 hour in the recovery room. Of the 21 patients who have had sperm counts performed 3 or more months postoperatively 19 have counts equal to or more than 20 million per ml., with an average motility of 43 per cent. Exclusive of the surgeon's fee, which is the same for inpatient and outpatient vasovasostomies, the average cost of the operation was +650, a savings of 41 per cent over the cost of an outpatient microsurgical vasovasostomy under general anesthesia and of 61 per cent over the cost of the procedure done on an inpatient basis under general anesthesia. The operation as described is safe and economical with minimal morbidity and has results comparable to those obtained with more complex and extensive vasovasostomy techniques.

Adult↗
PubMed1983

Sensitivity of preincubated lymphocytes to suppressor regulation.

DNA synthesis of human peripheral blood lymphocytes increases if Con A is added to the culture after 24 h preincubation at 37 degrees C. During preincubation the mitogen reactive lymphocytes lose their sensitivity to the suppressive effect of autologous mitomycin-treated mononuclear leukocytes, and of supernatants of autologous preincubated cells. The reactive lymphocytes preincubated at 4 degrees C retain their sensitivity to the suppressive effect of regulatory cells and their supernatants. It is assumed that the enhancement of mitogen response after preincubation at 37 degrees C is caused by a decrease of suppressor regulation of human lymphocytes. Prostaglandins may be regarded as one of the mediators of the suppression.

Alprostadil↗
PubMed1982

Catheter-induced ablation of the atrioventricular junction to control refractory supraventricular arrhythmias.

Five patients with recurrent bouts of supraventricular tachycardia proved resistant or became intolerant of both conventional and experimental drugs. These patients were subjected to a new procedure involving delivery of DC shocks to an electrode catheter positioned adjacent to the His bundle. Complete atrioventricular (AV) block was produced in all, one patient died suddenly six weeks after shock therapy, and the remainder had complete AV block with follow-up intervals ranging from four to 12 months. Shock therapy was associated with mild elevations of creatine phosphokinase MB (31 +/- 18 units), but there was no hemodynamic evidence of tricuspid insufficiency. If this new technique proves safe and effective, it should supplant the need for open heart surgical procedures for His-bundle ablation.

Adult↗
PubMed1982

Reentry confined to the atrioventricular node: electrophysiologic and anatomic findings.

A patient with recurrent disabling, paroxysmal supraventricular tachycardia refractory to drug treatment underwent electrophysiologic studies. The paroxysmal supraventricular tachycardia was found to be due to atrioventricular (A-V) nodal reentry. The patient died shortly after surgical His bundle section and detailed anatomic studies were performed. These showed fatty infiltration of the approaches to the sinoatrial node, atrial preferential pathways, and A-V node and common bundle. The A-V node was mechanically damaged and the common His bundle was completely severed. These abnormalities were clearly delineated and there was no evidence of an atrio-His bundle bypass tract to an accessory A-V node. Specifically, the central fibrous body and pars membranacea were defined and no atrial muscular fibers pierced these structures to joint the A-V bundle. It is concluded that paroxysmal supraventricular tachycardia due to A-V nodal reentry can be confined to the A-V node.

Atrioventricular Node↗
PubMed1982

Artificial sphincters in children with neurogenic bladders: long-term results.

Inflatable bladder sphincters (models AS 721 and AS 792) were implanted in 10 boys and 5 girls, between 5 and 17 years old, who had neurogenic bladders without residual urine or reflux and with normal renal function. Of the boys 9 are continent with an average followup of 51.5 months, whereas only 1 of the girls is continent. The incidence of mechanical failures is lower with the new AS 792 sphincter (2 of 11 versus 7 of 13 devices), and the 2 erosions occurred in girls whose bladder necks were opened during implantation. The artificial sphincter is useful in boys with neurogenic bladders without residual urine if bladder spasticity is controlled. We use the device in girls only when pharmacological methods and intermittent catheterization have failed. We have been satisfied with the long-term results even if reoperations were needed.

Adolescent↗
PubMed1982

Electrophysiologic effects of disopyramide in patients with atrioventricular nodal dysfunction.

Seventeen patients with first-degree or Mobitz I atrioventricular (AV) block and narrow QRS complexes underwent electrophysiologic drug testing before and after i.v. administration of disopyramide. Disopyramide did not significantly change the mean sinus cycle length (895 +/- 131 vs 877 +/- 119 msec), mean maximal sinus node recovery time (1134 +/- 160 vs 1133 +/- 13 msec), mean atrial effective refractory period (314 +/- 72 vs 307 +/- 54 msec), mean AV nodal conduction time (187 +/- 79 vs 180 +/- 73 msec) or the mean paced cycle length at which AV nodal Wenckebach conduction occurred (545 +/- 144 vs 497 +/- 130 msec) after disopyramide. The mean AV nodal effective refractory period decreased significantly (from 535 +/- 137 to 521 +/- 122 msec), and both infranodal conduction time and the paced ventricular cycle length producing ventriculoatrial block increased significantly (from 56 +/- 12 to 63 +/- 13 msec and from 625 +/- 158 to 655 +/- 157 msec, respectively). We conclude that i.v. disopyramide administered in a dose resulting in therapeutic blood levels showed no adverse effects on AV nodal conduction in patients with AV nodal dysfunction. In contrast, i.v. disopyramide depressed retrograde AV conduction.

Aged↗
PubMed1982

Sonography of splenic abscess.

Gray-scale sonographic examination was performed in seven cases of splenic and parasplenic abscess. The splenic abscesses appeared as irregular, poorly defined anechoic masses with varying internal echogenicity and acoustical transmission. Increased echogenicity and distal acoustical shadowing due to gas within the abscess were also noted. Gray-scale sonography was instrumental in the diagnosis of splenic abscess in this group of patients whose symptomatology was of uncertain etiology.

Abscess↗
PubMed1982

High-density lipoproteins and the proliferation of human tumor cells maintained on extracellular matrix-coated dishes and exposed to defined medium.

The ability of high-density lipoprotein (HDL) to support the growth of an established tumor cell line exposed to defined medium supplemented with transferrin has been examined. Low-density A-431 carcinoma cells maintained on extracellular matrix- or fibronectin-coated dishes proliferated actively when exposed to a synthetic medium supplemented with HDL, 500 micrograms protein per ml. Epidermal growth factor added at concentrations above 0.5 ng/ml inhibited cell growth, while at concentrations above 5 ng/ml it was cytotoxic. Among the various substrata tested for their ability to support the active proliferation of low-density A-431 cells when exposed to transferrin and HDL, plastic was the least efficient. On fibronectin-coated dishes, cells ceased to proliferate after 8 population doublings, while on extracellular matrix-coated dishes cells could be passaged for 50 population doublings. In the case of colon carcinoma, rhabdomyosarcoma, and Ewing's sarcoma cells exposed to medium supplemented with transferrin, the addition to the cultures of HDL alone resulted in a growth rate and final cell density which were similar to those observed when cells were exposed to serum-supplemented medium. In the case of the mammary carcinoma cell lines MCF-7 and ZR-75-1, HDL also supported cell growth, although to a lesser extent than did serum. The present study therefore indicates that HDL is capable of supporting, either totally or partially, the in vitro proliferation of tumor cells.

Blood↗
PubMed1982

Free latissimus dorsi muscle flap coverage of an electrical burn of the lower extremity.

High-voltage electrical injury results in progressive deep tissue necrosis after debridement, often resulting in amputation when the extremity is involved. Early debridement and coverage with a vascularized free muscle flap, when local flaps are unsuitable, may protect partially devitalized structures, preserve function, and reduce the incidence of amputation. A successful case of free latissimus dorsi muscle flap coverage of an electrical burn to the lower extremity is presented.

Adult↗