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Biomedical subjects

R Gomez

Publications and source records attributed to R Gomez.

At least 145 records · Page 8Linked to original sources
PubMed1993

The relationship between spontaneous rupture of membranes, labor, and microbial invasion of the amniotic cavity and amniotic fluid concentrations of prostaglandins and thromboxane B2 in term pregnancy.

OBJECTIVE: The purpose of this study was to examine the relationship between rupture of membranes, labor, and microbial invasion of the amniotic cavity and amniotic fluid concentrations of eicosanoids in patients with spontaneous rupture of membranes at term. STUDY DESIGN: Amniotic fluid was retrieved by transabdominal amniocentesis from patients with rupture of membranes and patients with intact membranes at term. Studies to determine the microbial state of the amniotic cavity included culture for bacteria and mycoplasmas, Gram stain, amniotic fluid white blood cell count, and Limulus amebocyte lysate. Eicosanoids (prostaglandin E2, prostaglandin F2 alpha and its stable metabolite, 6-keto-prostaglandin F1 alpha, and thromboxane B2) were determined with sensitive and specific radioimmunoassays validated for human amniotic fluid. Statistical inference was conducted with analysis of variance and linear contrast. RESULTS: (1) Spontaneous rupture of membranes at term was associated with a significant increase in amniotic fluid concentrations of all eicosanoids measured in this study except 6-keto-prostaglandin F1 alpha. (2) Early labor in patients with rupture of membranes was associated with a significant increase in the amniotic fluid concentration of all eicosanoids. (3) A significant increase in amniotic fluid eicosanoids in women with microbial invasion of the amniotic cavity could not be documented. CONCLUSIONS: Whereas preterm labor in the absence of microbial invasion of the amniotic cavity is not associated with a significant increase in amniotic fluid concentrations of prostaglandins, a clear increase was documented in women with early labor after spontaneous rupture of membranes. These observations suggest that there are fundamental differences in the biochemistry of term and preterm parturition.

Amnion↗
PubMed1993

Genital self-mutilation.

We report a series of 14 patients with 19 self-inflicted genital injuries during a period of 10 years. Of the patients 65% were psychotic and 35% were not psychotic. Repeated attempts at genital self-mutilation occurred in 31% of the cases, mainly in the psychotic group. A history of alcohol and/or drug abuse was present in 55% of the cases. Injuries varied from simple laceration of penile or scrotal skin to actual amputation of the penis or testis. The degree of injury did not differ between the psychotic and nonpsychotic patients. Surgical management and outcome varied according to the severity of the injury, the delay in presentation for treatment, and the degree of alteration in the mental status and behavior. Followup of 9 patients showed good cosmetic results with no immediate or delayed complications related to the injury. The functional results in patients with penile replantation were satisfactory. In 1 patient a urethral stricture developed that was successfully managed endoscopically. Erectile function was difficult to assess because of the marked diversity of sexual behavior in this group.

Adult↗
PubMed1993

Effects of nerve stimulation on blood flow in the urinary bladder, urethra and pelvic floor in the dog.

Pelvic organs have triple innervation from the pelvic, sympathetic and pudendal nerves. Peripheral effects can be studied by neurostimulation of the nerves, whereas the topography of the spinal cord neurons can be determined by horseradish peroxidase tracing. We have evaluated the neurophysiologic effects of the nerves at their target organs by intraoperative electric stimulation and compared the effects to the anatomical innervation areas. These zonal areas were determined by blood flow alterations, measured with nine different microspheres. Pelvic nerve stimulation showed bladder contraction with no significant blood flow changes during stimulation. Sympathetic nerve stimulation caused moderate detrusor contraction and pressure increase in the bladder neck and intraprostatic area. Regional blood flow showed a four-fold increase in the bladder neck area during neurostimulation. Pudendal nerve stimulation revealed an intraurethral pressure increase with a 3.5-fold increase of blood flow in the sphincteric area and in the pelvic floor musculature.

Animals↗
PubMed1993

Endoscopic and bioptic findings in the upper gastrointestinal tract in patients with Crohn's disease.

A prospective study was carried out on 41 patients diagnosed as having Crohn's disease (CD) to evaluate the degree of upper gastrointestinal tract involvement. In 23 patients (56%), endoscopic alterations were found most frequently affecting the antrum and duodenum. Lesions encountered were: Aphthoid erosions, ulcers, thickening of folds, nodules, erythema and stenosis. Granulomas were found in biopsies in 19.5% of the patients: They were more frequent in those demonstrating endoscopic alterations (26%) than in those with normal endoscopic findings (11%). Clinical evolution was favorable with conventional treatment for CD and ranitidine, although the endoscopic lesions did not totally disappear in any cases. We conclude that upper gastrointestinal endoscopy with biopsies is useful in evaluating the extension of disease and can be of diagnostic value in cases of indeterminate colitis.

Adult↗
PubMed1993

A Pathfinder analysis of pedagogical knowledge structures: a follow-up investigation.

This study is an extension of an earlier investigation of undergraduate students' acquisition of key pedagogical concepts in a physical education teaching methodology course. In that study, Pathfinder, a method for eliciting associative memory networks, was used to describe and compare the pedagogical knowledge structures of students to that of the course instructor. After the course, students' pedagogical knowledge structures corresponded more closely with that of the instructor, and students who corresponded the closest performed better in the course. The results raised an interesting issue regarding the acquisition of knowledge in undergraduate students. Did students acquire a generalizable body of pedagogical knowledge applicable beyond the context of the teaching methodology course or a highly contextualized reflection of their course instructor's knowledge base? In the present study the external validity of the pedagogical knowledge base was examined by using Pathfinder to compare the knowledge structures of students from the initial investigation with knowledge structures of five experienced teacher educators from five different teacher education programs. The findings indicated that students' knowledge structures became significantly more correspondent with that of the experienced teachers' structures from the beginning to the end of the course. Also, students' correspondence with teacher educators' structures following instruction was found to be significantly correlated with academic and teaching performance. The findings point to the external validity of the domain of knowledge under study and the robustness of Pathfinder for capturing pedagogical knowledge.

Adult↗
PubMed1993

Ganciclovir prophylaxis decreases frequency and severity of cytomegalovirus disease in seropositive liver transplant recipients treated with OKT3 monoclonal antibodies.

The efficacy of ganciclovir, given prophylactically, to prevent cytomegalovirus-related disease was evaluated in liver transplant recipients, mostly seropositive, under treatment with OKT3 monoclonal antibodies. The incidence of cytomegalovirus disease and visceral involvement was reduced, respectively, from 52 and 36% in the control group to 12 and 8% in the ganciclovir-treated patients. Leukopenia was a frequent (32%) side effect of ganciclovir administration.

Adult↗
PubMed1993

Liver transplantation in patients with a previous portasystemic shunt.

Over a six-year period, 4 patients who had undergone previous portasystemic shunt procedures received an orthotopic liver transplantation (OLTx). The types of shunt used were porta-caval (2 patients), distal splenoral shunt (1 patient), and the Sugiura procedure (1 patient). The mean interval between shunt and transplantation was 3.25 years. There was no statistical difference in blood, plasma, and crystalloid requirements, cold and warm ischemia, duration of the transplantation procedure or postoperative complications between these 4 patients and any of the others.

Adult↗
PubMed1993

Effect of adenosine 5'-triphosphate on secretagogue-stimulated (14C)-aminopyrine accumulation by rabbit isolated gastric glands.

The effect of adenosine 5'-triphosphate (ATP) on gastric acid secretion stimulated by histamine, carbachol and dibutyryl-cAMP (db-cAMP) was studied using glands isolated from rabbit gastric mucosa. The (14C)-aminopyrine (AP) accumulation method was used as an index of acid production by the gastric glands. Histamine-stimulated AP accumulation was significantly inhibited by ATP (10 mumol/l-1 mmol/l). The inhibitory action of ATP appeared to be specific, inasmuch as this nucleotide had no significant effect on basal secretion or secretion stimulated by carbachol or db-cAMP. The antisecretory effect of ATP on histamine-stimulated glands was not affected by the P1-purinoceptor antagonist, theophylline. Pretreatment of glands with indomethacin, a well known prostaglandin synthesis inhibitor, led to a significant reduction of the inhibitory responses to ATP. These results show that ATP inhibits the histamine-stimulated AP accumulation by rabbit isolated gastric glands and suggest that this effect is not due to an ectoenzymatic conversion of ATP into adenosine but to a direct effect of ATP which may be mediated via a P2-purinoceptor subtype linked to prostaglandin production.

Adenosine Triphosphate↗
PubMed1992

Matrix vesicles are enriched in metalloproteinases that degrade proteoglycans.

This study examined the presence of extracellular matrix processing enzymes in matrix vesicles produced by rat costochondral resting zone and growth zone chondrocytes in culture. Optimum procedures for the extraction of each enzyme activity were determined. Enzyme activity associated with chondrocyte plasma membrane microsomes was used for comparison. There was a differential distribution of the enzyme activities related to the cartilage zone from which the cells were isolated. Acid and neutral metalloproteinase (TIMP), plasminogen activator, and beta-glucuronidase were highest in the growth zone chondrocyte (GC) membrane fractions when compared with matrix vesicles and plasma membranes isolated from resting zone chondrocyte (RC) cultures. There was a threefold enrichment of total and active acid metalloproteinase in GC matrix vesicles, whereas no enrichment in enzyme activity was observed in RC matrix vesicles. Total and active neutral metalloproteinase were similarly enriched twofold in GC matrix vesicles. TIMP, plasminogen activator, and beta-glucuronidase activities were highest in the plasma membranes of both cell types. No collagenase, lysozyme, or hyaluronidase activity was found in any of the membrane fractions. The data indicate that matrix vesicles are selectively enriched in enzymes which degrade proteoglycans. The highest concentrations of these enzymes are found in matrix vesicles produced by growth zone chondrocytes, suggesting that this may be a mechanism by which the more differentiated cell modulates the matrix for calcification.

Animals↗
PubMed1992

Matrix vesicles contain metalloproteinases that degrade proteoglycans.

This study explored whether extracellular matrix processing enzymes are present in matrix vesicles produced by rat costochondral resting zone and growth zone chondrocytes in culture. It was found that there was a differential distribution of enzyme activities related to the cartilage zone from which the cells were isolated. There was a 3-fold enrichment of total and active acid metalloproteinase in growth zone chondrocyte (GC) matrix vesicles whereas no enrichment in enzyme activity was observed in resting zone chondrocyte (RC) matrix vesicles. Total and active neutral metalloproteinase were similarly enriched 2-fold in GC matrix vesicles. TIMP, plasminogen activator and beta-glucuronidase activities were highest in the plasma membranes of both cell types. No collagenase, lysozyme, or hyaluronidase activity was found. The data indicate that matrix vesicles are selectively enriched in enzymes that degrade proteoglycans. The highest concentrations of these enzymes are found in matrix vesicles produced by growth zone chondrocytes, suggesting that this may be a mechanism by which the more differentiated cell modulates the matrix for calcification.

Animals↗
PubMed1992

Differential regulation of prostaglandin E2 synthesis and phospholipase A2 activity by 1,25-(OH)2D3 in three osteoblast-like cell lines (MC-3T3-E1, ROS 17/2.8, and MG-63).

Both 1,25-(OH)2D3 and prostaglandin E2 (PGE2) stimulate alkaline phosphatase activity in MC-3T3-E1 cells. Previous studies, demonstrating a correlation between 1,25-(OH)2D3-dependent alkaline phosphatase and phospholipase A2 activities in matrix vesicles isolated from growth cartilage chondrocyte cultures, suggest that one mechanism of vitamin D action may be via autocrine or paracrine action of PGE2. Since most PGE2 is derived from arachidonic acid released by the action of phospholipase A2, we examined whether 1,25-(OH)2D3 stimulates phospholipase A2 activity in three osteoblastic cell lines: ROS 17/2.8 cells, MC-3T3-E1 cells, and MG-63 cells. 1,25-(OH)2D3-dependent alkaline phosphatase and phospholipase A2 activity were correlated with production of PGE2 and PGE1 in the MC-3T3-E1 cells. Alkaline phosphatase specific activity was enriched in the matrix vesicles produced by all three cell types and was stimulated by 1,25-(OH)2D3 at 10(-8) to 10(-7) M. Although phospholipase A2 specific activity was enriched in the matrix vesicles produced only by the ROS 17/2.8 cell cultures, stimulation of this enzyme activity was observed only in the MC-3T3-E1 cell cultures. The effects of 1,25-(OH)2D3 on phospholipase A2 were dose-dependent and were significant at 10(-8) to 10(-7) M. There was a significant increase in PGE2 production in the MC-3T3-E1 cell cultures only. Indomethacin reduced PGE2 production to base line values. Even at baseline, MC-3T3-E1 cells produced ten times more PGE2 than did the ROS 17/2.8 or MG-63 cell cultures. The effects of 1,25-(OH)2D3 on PGE1 were comparable to those on PGE2.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Hematuria as a predictor of abdominal injury after blunt trauma.

Among the 1,484 patients included in the Renal Trauma Project with evidence of blunt trauma and hematuria, 160 patients were found to have both hematuria and a significant intra-abdominal injury not related to the genitourinary system. The incidence of abdominal injury generally increased with the degree of hematuria, approaching 24% in patients with gross hematuria. For each category of degree of hematuria, patients with shock had a significantly higher incidence of abdominal injury (p < 0.05) than patients without shock. The incidence of abdominal injury in patients with microscopic hematuria and shock was 29%, and it was 65% for patients with both gross hematuria and shock. All patients with gross hematuria after blunt abdominal trauma and all patients with microscopic hematuria and a history of shock should be evaluated for both urologic and extra-renal abdominal injuries.

Abdominal Injuries↗
PubMed1992

Human bites to the penis.

Victims of human bites to the penis often do not seek timely medical attention and dangerous progression of infection may ensue. We present 5 cases, 1 of which evolved into necrotizing fasciitis of the lower abdomen. Recommendations for management of these wounds include aggressive local wound care, empiric antibiotics and careful observation for necrotizing complications.

Adult↗
PubMed1992

Major bacterial infections following liver transplantation: a prospective study.

The incidence and characteristics of major bacterial infections were studied prospectively in 50 consecutive adult patients who underwent liver transplantation (LT). All patients received the same protocol of immunosuppression, bowel decontamination, antibiotics prophylaxis, and follow-up. Thirty-two patients (64%) had at least one episode of major bacterial infection. One death was directly related to a bacterial infection, accounting for 13% of postoperative mortality. The most critical period for infection was the first 2 months after surgery, when 69% of the infections occurred. The most frequent clinical presentations were bacteremia, pneumonia and abdominal abscesses. Eighty percent of the bacteremias had an identifiable source, the most frequent being intravascular catheters. Gram-positive microorganisms (69%) predominated over gram-negative rods (26%) and anaerobes (5%). The use of selective bowel decontamination (SBD) with norfloxacin may explain this predominance. Major bacterial infections are an important source of morbidity and mortality after LT. Efforts to prevent these infections and to determine their source and specific treatment, will improve the management and the outcome of these patients in the future.

Adult↗
PubMed1992

Squamous carcinoma of oral tongue: prognostic significance of flow-cytometric DNA content.

Thirty-eight squamous carcinomas of the mobile tongue were flow cytometrically analyzed for their DNA content, and the results correlated with clinicopathologic parameters and patient survival. Tumor size (p = 0.01), depth of invasion (p = 0.05), histologic differentiation (p = 0.03), ploidy pattern (p = 0.01), and S-phase (p = 0.001) showed significant correlation with patients' clinical outcomes in univariate analyses. A multifactorial regression analysis of all significant parameters indicated that S-phase percentage and depth of tumor invasion were independent prognostic factors in this cohort.

Adult↗