Biomedical subjects

P Fuentes

Publications and source records attributed to P Fuentes.

At least 55 records · Page 3Linked to original sources

PubMed1997

The effect of neomycin on the kidney function of the horse.

The toxic effect of neomycin on the horse kidney was studied. Twelve horses were used, and were divided at random into three groups of four. The first group was treated twice a day with 10 mg/kg I.M. for 15 days and then euthanised; kidney and liver samples were studied and no histopathological changes were observed. Group 2 was treated with neomycin sulphate as in group 1, and group 3 was used as control. Blood samples were taken at 8.00 h and 20.00 h daily from both neomycin treated and control horses. Serum creatinine, potassium, sodium and urinary creatinine remained without change. On day 6 of treatment plasma urea (Urea)p decreased to 5.6 +/- 2.0 mmol/L (P < 0.001) as compared with controls (8.0 +/- 2 mmol/L). Urinary excretion of GGT increased on the third day of treatment to 118.6 +/- 1 IU/L for treated and 89 +/- 8 IU/L for controls (P < 0.001). Thereafter, GGT continued to be elevated significantly for the duration of the experiment, as compared with controls. The (GGT)/(Cr)u ratio increased significantly on the 9th day of treatment, and continued to be elevated for 6 days after treatment. Neomycin kinetics were similar during treatment. It was concluded that neomycin, in the dose used, was not harmful to kidney function in the horse.

Animals↗

PubMed1997

[Endosonography in the preoperative evaluation of cancers of the esophagus].

OBJECTIVE: To assess the diagnostic accuracy of endoscopic ultrasonography (EUS) for the local and regional staging of esophageal cancer, and its possible alteration resulting from the performance of preoperative chemoradiation. METHODS: Prospective study of 85 consecutive patients with esophageal cancer evaluated by EUS and operated on between January 1992 and December 1995. 28 of these patients had received previous induction therapy. In all cases, EUS examination was performed by the same physician not informed about the results of previous morphological explorations. Histopathological analysis of all operative specimens was performed by the same pathologist, not informed about the results of EUS. Data were collected by another independent observer. RESULTS: EUS examination resulted in incomplete staging in 8 patients (9.5%) with severe stenosis precluding endoscope passage. The accuracy, specificity and sensitivity of EUS in detecting the depth of esophageal involvement (T0-2 vs. T3-4) were 82.3%, 78%, and 86% respectively, and 72%, 70%, and 73% respectively for lymph node metastasis. The overall accuracy of EUS in identifying the preoperative stage was 67%, with a clear-cut alteration when patients had received induction therapy (61% vs 72%). On the other hand, 7 (64%) of the 11 patients thought to have a complete response at endosonography had no residual tumor. CONCLUSION: EUS provides precise information for the preoperative identification of locally advanced esophageal tumor, even after induction therapy. The latter alters the diagnostic accuracy of EUS, although complete responders could be identified in two-thirds of cases.

Adult↗

PubMed1997

Changing patterns and surgical results in adenocarcinoma of the oesophagus.

BACKGROUND: Prognosis of oesophageal adenocarcinoma is notoriously dismal. To examine the changing patterns of and treatment strategies for this disease, the longitudinal experience of a single institution over 16 years is reported. METHODS: The study comprised a retrospective review of 551 consecutive patients operated on for oesophageal cancer between 1979 and 1995, of whom 164 had adenocarcinoma. There were 13 women and 151 men whose mean age was 61 (range 17-82) years. RESULTS: The prevalence of adenocarcinoma (P = 0.002), that of early tumours (P < or = 0.10), and the resectability rate (P < or = 0.05) increased throughout the period whereas operative mortality rate decreased (P < or = 0.10). Surgical approach changed without influence on long-term survival. Patients referred from endoscopic surveillance programmes for Barrett's oesophagus (n = 16) had an improved survival rate compared with that of non-surveyed patients (P < or = 0.01). Overall 5-year survival after oesophagectomy (17 per cent) improved for the period 1991-1995 when compared with 1979-1982 (P < or = 0.02). Univariate analysis identified tumour node metastasis (TNM) stage, number of diseased lymph nodes, invasion of the oesophageal stump and occurrence of a postoperative complication as significant prognostic variables (P < or = 0.05). Multivariate analysis demonstrated that T stage (P = 0.0002) was the main independent predictor. CONCLUSIONS: Recent improvement of results reflects patient selection, increased prevalence of early tumours, and dramatic reduction of the risks from oesophagectomy. New therapeutic directions should be investigated for locally advanced tumours.

Adenocarcinoma↗

PubMed1997

[Severe bronchial stenosis with upstream bronchiectasis in an arc welder: causal relation or epiphenomenon?].

This case concerns an arc welder who presented suppurative bronchiectasis and episodes of purulent left side pleurisy in relation to cystic bronchiectasis of the left lower lobe and a very severe stenosis at the origin of the main left bronchus. The medicolegal problem was to assess the causal relationship between these lesions and occupational exposure. They do not come under the heading of table 44 of the General List and we made this the aim of discretionary award in front of a regional committee of compensation for occupational disease.

Bronchial Diseases↗

PubMed1997

[Recurrence after surgical treatment of epidermoid cancers of the esophagus. Therapeutic approach in 19 patients].

OBJECTIVES: The aim of this study was to report the management of 19 patients with recurrence of esophageal squamous cell carcinoma after surgical treatment. PATIENTS-METHODS: Nineteen patients with loco-regional recurrent invasion (n = 13) or metastasis (n = 6) of esophageal squamous cell carcinoma were included. Four of the 13 patients with loco-regional recurrent invasion had tracheal involvement. The treatment of the recurrence was a combined radiochemotherapy (n = 12) for loco-regional recurrent invasion in 11 cases and for metastasis in 1 case, associated with a tracheal prosthesis in 1 patient. The other treatments were chemotherapy alone (n = 5), esophageal prosthesis (n = 1) and surgical treatment (n = 1). RESULTS: There were 7 objective responses among the 12 patients treated with combined radiochemotherapy and none in the group treated with chemotherapy alone. Grade 3-4 toxicity was noticed in 2 cases (severe mucositis). Survival rate of the 19 patients was 52.6% at 1 year and 13.1% at 2 years; it was linked with general health (P = 0.09) and with tracheal involvement (P = 0.04). Survival rate of the 12 patients treated by combined radiochemotherapy was higher: 66% at 1 year and 22.2% at 2 years (median survival time = 16 months). CONCLUSION: Active medical treatment of recurrence of esophageal squamous cell carcinoma by combined radiochemotherapy can provide a median survival time of 16 months, with a moderate toxicity.

Adult↗

PubMed1997

Regional differentiation of the blood-epididymis barrier in stallion (Equus caballus).

The occurrence, localization and ultrastructural characteristics of a blood-tissue barrier throughout the stallion proximal seminal excurrent duct system were studied by the exclusion of electron-dense tracers and freeze-fracture techniques. Striking differences were observed in the distribution of lanthanum tracer and in the geometrical organization of the zonulae occludentes along the ductus efferentes, epididymides and vas deferens. The zonulae occludentes domain, the principal structural component of the blood-epididymis barrier, differed in permeability, width and strand numbers along the ductus. The flow of tracer was not impeded by the vascular endothelium, the peritubular myoid layer or other surface membrane specialization. The tight junctions of the ductuli efferentes are poorly developed but unlike those of rats, guinea pigs or man they are not associated with gap junctions. The result of the tracer experiments and the low number of tight junctional strands in the ductuli efferentes suggests that the barrier of the ductuli efferentes corresponds to the 'leaky type'. In the epididymis the zonulae occludentes are well developed throughout the duct. The greatest number of strands, especially in the cauda epididymidis regions, correlates well with a decreased junctional permeability in this area. Another evidence for the existence of the stallion blood-epididymis barrier are the differences in the proteins electrophoretic profiles between blood plasma as compared with the fluid inside the seminal ductus. This junctional complexes contribute to create a highly defined luminal fluid microenvironment that ensures the sperm maturation and survival.

Animals↗

PubMed1997

[Induction treatment of locally advanced operable cancers of the esophagus. Prognostic significance of the histologic response].

OBJECTIVE: The purpose of this study was to determine the prognostic significance of the histopathological response to preoperative radio-chemotherapy in patients with locally advanced oesophageal cancer. METHODS: Among the 57 patients included in this open prospective study, the disease-free survival of 48 patients (8 females 40 males; mean age: 56.6 years +/- 8.4) who underwent an oesophagectomy after induction therapy for oesophageal squamous cell (n = 38) or adenocarcinoma (n = 10) was correlated with the histopathological findings. Chemoradiation included 2 cycles associating continuous 5 FU from D1 to 5 and from D22 to 26, cisplatyl on D1 and D22, 15 Gy/5d from D1 to 5 and from D22 to 26. Histopathological response was assessed on the operative specimens by routine examination of serial thin sections each 5 mm along the full oesophageal length, the resection margins and the lymph node dissection. RESULTS: A wide interindividual variability was seen regarding tissue changes related to induction therapy, with a grading in tumor regression and the possibility of dissociated effects on the various treatment targets: tumor, adenopathy and vessel invasion. The 5-year probability of disease-free survival was 22% for the 48 resected patients. The presence of a complete histopathological response (n = 12) did not preclude metastatic spread in half the cases. Furthermore, it did not result in improved survival when compared to that of non-responder patients. Survival of patients who had a complete or major oesophageal response (n = 29, 35% at 5 years) was significantly lower than that of patients who were operated on during the same period for a superficial oesophageal cancer at presentation (n = 29, 57% at 5 years; P = 0.03). After multivariate analysis according to the Cox model, downstaging of the primary tumor was not identified as an independent predictor of disease-free survival. CONCLUSIONS: Pathologic assessment of tumor regression on the operative specimen provides little prognostic information.

Adenocarcinoma↗

PubMed1997

[Endocrine function of the testicle in the Mexican crossbred ram at different times of the year and its opioidergic control during anoestrus].

This work was carried out with the objective of studying the endocrine function of the testes in the Mexican Crossbred Ram (Suffolk x Hampshire) during the different seasons of the year in a latitude of 19 degrees 13' N. Also studied was the opioidergic control of this gland during anoestrus. For this purpose 8 rams were used, from which 3 ml of jugular blood were obtained three times a week to study the seasonal fluctuations in plasma testosterone. The experiment was carried out from May 1993 until June 1994. The androgen was determined by radioimmunoassay. To study the opioidergic control of androgen secretion during seasonal anoestrous (May-June) four of the rams were selected at random and treated with 0.5 mg naloxone at 12 h intervals during 3 continuous weeks. It was observed that blood testosterone was lowest during long days, and concentration was highest during the breeding season. Chronic naloxone medication during anoestrus resulted in a significant increase in blood testosterone (P < 0.001), an effect that was evident after the first week of treatment. When naloxone administration was discontinued, blood testosterone levels returned to basal. With this experiment it was demonstrated that an opioid antagonist such as naloxone administered in low doses, is capable of altering plasma testosterone concentration in the anoestrus ram, giving further support to endogenous opioids as important modulators of reproduction in seasonal breeders such as sheep.

Anestrus↗

PubMed1997

[Esophageal perforations and ruptures: a plea for conservative treatment].

OBJECTIVES: To identify the determinants and results on conservative management of oesophageal perforations and ruptures. METHODS: Retrospective clinical review of 34 consecutive patients (mean age: 62 years) treated for cervical (n = 10) or thoracic (n = 24) oesophageal disruption between 1985 and 1996. Causes were: spontaneous rupture (n = 10), instrumental perforation (n = 16), alimentary foreign body (n = 6), and blunt (n = 1) or penetrating trauma (n = 1). The diagnostic delay exceeded 24 hours in 15 cases. RESULTS: A nonoperative management was achieved in 8 patients with no mortality. A conservative surgical treatment was attempted in 23 patients, primary repair in 21 and open drainage in 2, with a 17.4% mortality. Resection (n = 2) or exclusion (n = 1) was performed in 3 patients with no early mortality, but one of them died as result of the subsequent reconstructive operation to restore oesophageal continuity. Overall morbidity was linked to the spontaneous cause of the perforation. Outcome of patients undergoing primary repair was not influenced by the diagnostic delay nor the surrounding sepsis. CONCLUSION: Conservative management should be advocated for the treatment of oesophageal perforations and ruptures, even in case of delayed diagnostiqiagnosis, regardless of the surrounding sepsis and cause of disruption.

Adult↗

PubMed1997

[Pulmonary Wegener's disease mimicking tuberculosis].

We report a case of early Wegener's disease mimicking tuberculosis in a 36 year old man. Lungs are solely affected for 6 months. Unusual appearance of radiographic features with large apical excavations explain the delai for the diagnosis. We discuss morphological features in the lungs and kidney.

Adult↗

PubMed1996

Esophageal cancer resection in the elderly.

OBJECTIVE: Esophageal cancer is a disease whose prognosis is dismal and its surgery involves considerable risks, consequently the opportunity of esophageal resection in elderly patients with esophageal cancer is questionnable. The aim of this study was to analyze, with respect to their age, the outcome of 386 consecutive patients who underwent esophagectomy and simultaneous replacement for cancer. METHODS: A chart review of all patients with esophageal carcinoma admitted to our institution was undertaken for the period January 1979-December 1994. RESULTS: The portion of patients of 70 years of age and older (14.5%) has slightly increased during the period. Location to the lower third of the esophagus and adenocarcinoma type were prevalent in the 56 elderly patients (group I), but their postsurgical TNM staging was identical to that of the 330 younger patients (group II). Other clinical features, i.e. preoperative weight loss and the presence of co-morbid diseases, however, were comparable in the two groups. Pulmonary function, as assessed by spirometry, was significantly worse among the older patients, but blood gas determinations were not different. Operative mortality was comparable, between the two groups (10.7% vs 11.2%). Major morbidity included anastomotic leak (10.7% vs 13.6%) and pulmonary complications (17.9% vs 20.6%) in both groups. Excellent palliation of dysphagia was achieved in 92% of the 50 group I patients who survived the operation. Long-term survival was not different in elderly patients (5-year rate: 17%) when compared with that of younger patients (18.9%). CONCLUSION: These data suggest that esophagectomy can be performed safely in selected septuagenarian patients, thus allowing a substantial survival with excellent functional status in a portion of these patients.

Adenocarcinoma↗

PubMed1996

Human sperm coating antigen from seminal plasma origin.

Sperm surface glycoproteins may be involved in sperm-zona pellucida recognition. Some of these coating proteins are of seminal plasma origin and their expression may change in the process of capacitation and acrosome reaction. Sperm specific monoclonal antibodies (mAb) define the presence and role of sperm membrane associated proteins. We have isolated a monoclonal antibody (SEM-12) specific for human sperm that shows, by indirect immunofluorescence, a discontinuous distribution of the antigen on the head and tail surfaces of non capacitated sperm. This antigen is also present in human seminal plasma as detected by ELISA. The antigen is detectable in sperm of goat, ram, and mouse. Two proteins in the range of 80-84 kDa have been isolated by affinity chromatography with SEM-12 mAb. The same result is obtained by immunoprecipitation. This antibody inhibits sperm motility and acrosome reaction (spontaneous and A23187 ionophore induced.

Acrosin↗

PubMed1996

Balance between alveolar macrophage IL-6 and TGF-beta in lung-transplant recipients. Marseille and Montréal Lung Transplantation Group.

Acute inflammation in the lung is characterized by a phase of tissue injury followed by a phase of tissue repair. When the latter is excessive, fibrosis occurs. Alveolar macrophages (AM) can produce cytokines involved in both phases of acute lung inflammation, notably interleukin-6 (IL-6), involved in injury and transforming growth factor-beta (TGF-beta), mediating repair. We hypothesized that AM were activated in both phases, and studied IL-6 and TGF-beta production by AM during complications of lung transplantation, acute rejection (AR), and cytomegalovirus pneumonitis (CMVP). In addition, we analyzed these cytokines in bronchiolitis obliterans (BO), a fibrotic complication of lung transplantation linked to previous AR and CMVP. At the onset of AR and CMVP, IL-6 secretion increased, whereas AM TGF-beta content was increased, but not its secretion. In contrast, with time, IL-6 reached control value whereas TGF-beta secretion rose significantly. In BO, IL-6 was not oversecreted, but TGF-beta increased, notably before functional abnormalities occurred. These results show that during acute complications of lung transplantation, AM display an early activation with oversecretion of IL-6, which is involved in tissue injury, counterbalanced by a late activation in which TGF-beta predominates, mediating tissue repair. The results provide new insights into the pathogenesis of BO, which is linked to acute complications of lung transplantation through this biphasic AM activation.

Adolescent↗

PubMed1996

[Hemiballismus heralding thrombosis of the basilar artery].

We present a patient with top-of-the-basilar syndrome that was preceded by hemiballismus and progressed to coma and tetraplegia. Magnetic resonance imaging showed extensive infarction in the basilar artery territory. Cerebral angiography confirmed basilar artery obstruction. The patient died in spite of anticoagulation therapy.

Aged↗

PubMed1996

[Technique and results of colonic esophagoplasties].

From 1985 to 1995, 60 patients with a mean age of 52 +/- 12 years [24-78] underwent colon interposition for esophageal replacement. Indications were esophageal cancer (n = 37), benign stricture (n = 13), iatrogenic esophageal fistula (n = 5), achalasia with megaesophagus (n = 3), and necrosis of a previous substitute (n = 2). Colon interposition represented only 18.5% of all operations performed for oesophageal replacement during the same period. The colon was selected because of inadequate stomach in 33 cases (55%). Long-segment conduit based on the ascending branch of the left colonic artery was the preferred method and could be used in 52 patients (86.7%). The colon was placed in the esophageal bed in 38 patients (63.3%), substernally in 21 (35%), and subcutaneously in 1. Overall operative mortality and morbidity were 8.3% and 65% respectively. Five-year survival rate was 9% in the 37 patients with esophageal cancer. Seven patients (13.5%) required one or more dilatations of the esophagocolonic anastomosis. At last follow-up, 34 patients (65.4%) had no difficulty eating. Multivariate analysis identified the conduit position in the posterior mediastinum as an independent predictor of good functional result (p = 0.0018). We conclude that colon interposition for esophageal replacement provides satisfactory and durable function; however, early mortality and morbidity are substantial.

Adult↗

PubMed1996

[Surgical treatment of esophageal cancer in patients over 70 years of age].

As the population continues to age, septuagenarian patients with esophageal cancer are frequently referred for surgical treatment. The aim of this study was to analyze with respect to their age the outcome of 386 patients who underwent esophagectomy and simultaneous reconstruction from 1979 to 1994. The portion of patients of 70 years of age and older (14.5%) has slightly increased during the period. Location to the lower third of the esophagus and adenocarcinoma type were prevalent in the 56 elderly patients (Group I), but postsurgical TNM staging was identical to that of the 330 younger patients (Group II). Other clinical features, i.e., preoperative weight loss and presence of co-morbid diseases, however, were comparable in both groups. Pulmonary function, as assessed by spirometry, was significantly worse among the older patients, but blood gas determinations were not different. Operative mortality was comparable among the 2 groups (10.7% vs 11.2%). Major morbidity included anastomotic leak (10.7% vs 13.6%) and pulmonary complications (17.9% vs 20.6%) in both groups. Long term survival was not different in elderly patents (5-year rate: 17%) when compared with that of younger patients (18.9%). These data suggest that 1) esophagectomy can be performed in selected septuagenarian patients with an acceptable risk, and 2) long-term survival with excellent functional status is attainable in this age group in a portion of these patients.

Age Factors↗

PubMed1995

Structural domains of streptokinase involved in the interaction with plasminogen.

Two fragments of recombinant streptokinase, comprising amino acids Val143-Lys293 (17-kDa rSK) or Val143-Lys386 (26-kDa rSK), were cloned and expressed in Escherichia coli, purified to homogeneity and their interactions with plasmin(ogen) were evaluated. Both 17-kDa rSK and 26-kDa rSK bound to plasminogen with a 1:1 stoichiometry and with affinity constants of 3.0 x 10(8) M-1 and 12 x 10(8) M-1, respectively, as compared to 6.3 x 10(8) M-1 for the binding of intact recombinant streptokinase to plasminogen. Binding of 17-kDa rSK to plasminogen-Sepharose was displaced by addition of increasing concentrations of recombinant streptokinase, whereas bound recombinant streptokinase was not displayed by 17-kDa rSK. In equimolar mixtures of plasminogen and 26-kDa rSK, the appearance of amidolytic activity as monitored with a chromogenic substrate, was significantly delayed compared to the equimolar mixture with recombinant streptokinase (60% of the maximal activity after 30 min, compared to maximum activity within < or = 2 min). In contrast, no amidolytic activity was generated in equimolar mixtures of plasminogen and 17-kDa rSK. Plasminogen was rapidly activated by catalytic amounts (1:100 molar ratio) of recombinant streptokinase (60-70% within 10-15 min), whereas only 4% of the plasminogen was activated within 60 min with 26-kDa rSK, and no plasmin was generated with 17-kDa rSK. Complexes of plasmin with 17-kDa rSK or with 26-kDa rSK were very rapidly inhibited by alpha 2-antiplasmin (apparent second-order inhibition rate constant of approximately 2 x 10(7) M-1 s-1), whereas the complex with recombinant streptokinase was resistant to inhibition. With 26-kDa rSK, inhibition by alpha 2-antiplasmin resulted in dissociation of the complexes and recycling of functionally active 26-kDa rSK to other plasminogen molecules; 17-kDa rSK, in contrast, remained associated with the plasmin-alpha 2-antiplasmin complex. These findings suggest that different regions of the streptokinase molecule are involved in binding to plasminogen, in active-site exposure, and in impairment of the inhibition of plasmin by alpha 2-antiplasmin. Thus, the 17-kDa region spanning Val143-Lys293 in streptokinase mediates its binding to plasminogen but does not induce activation. Furthermore, this region does not interfere with the inhibition of the complex with plasmin by alpha 2-antiplasmin.

Amino Acid Sequence↗

PubMed1995

In vitro evaluation of donor liver preservation fluids on human hepatocyte function.

Successful liver transplantation depends on adequate preservation of cellular function. We therefore tested the effects of two currently used liver preservation fluids, Euro-Collins (EC) solution and University of Wisconsin (UW) solution, on the viability and some functional activities of hepatocytes isolated from human livers. Cells in primary culture were maintained under hypoxic (95% N2/5% CO2) and hypothermic (4 degrees C) conditions for 24 h, either in EC or UW solution. This treatment did not result in significant hepatocyte damage, as judged by phase contrast microscopy, intracellular LDH release, and the MTT mitochondrial test. However, neutral red uptake indicated that lysosomal functions were slightly affected (35% decrease) when compared to control conditions. At the end of the hypoxia/hypothermia period, hepatocyte monolayers were incubated at 37 degrees C under normoxic conditions for 24 h, in order to simulate the reperfusion of a transplanted liver. Three drugs--midazolam, diazepam, zidovudine--were used as diagnostic substrates to check the metabolic abilities of human hepatocytes replaced in normal conditions. Both phase I (hydroxylation, demethylation) and phase II (glucuronidation) metabolic reactions were affected by the hypoxia/hypothermia shock. Indeed, a 30%-50% decrease in these activities was observed as compared to values obtained in control hepatocytes. No difference could, however, be found at the cellular level regarding the solution used for cold storage. These results suggest that the superiority of UW over EC solution, already reported in clinical practice after transplantation of preserved human livers, was not due to a better preservation of the hepatocytes.

Antimetabolites↗