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Biomedical subjects

J Muñoz

Publications and source records attributed to J Muñoz.

At least 19 recordsLinked to original sources
PubMed1997

Diagnostic imaging of tibial periosteal ganglion.

A case of a soft tissue tumor situated in the anterior surface of the proximal end of the tibia in an adult patient is demonstrated by conventional radiographs, CT, and MRI. The lesion was well defined with respect to the adjacent soft tissue. The CT exam showed a soft tissue mass with external cortical erosion and thick spicules by periosteal reaction. On T1-weighted images the mass was homogeneous and of low signal intensity, whereas on T2-weighted images it showed a high signal intensity, with some septa in the mass. The differential considerations include a periosteal chondroma, a lipoma, a subperiosteal hematoma, an inflammatory process, a giant cell tumor of tendon sheath, and a parosteal osteosarcoma. The CT and MR features of these entities are reviewed as an aid in differential diagnosis of the periosteal ganglion.

Adult↗
PubMed1997

Accuracy of portal and forearm blood flow measurements in the assessment of the portal pressure response to propranolol.

BACKGROUND/AIMS: The portal pressure response to propranolol varies significantly in individual patients with cirrhosis. At present, propranolol responders can be identified only by measuring the hepatic venous pressure gradient. The aims of this study were: 1) to investigate whether the noninvasive monitoring of portal blood flow by pulsed Doppler ultrasound and forearm blood flow by strain-gauge plethysmography can predict the hepatic venous pressure gradient response to propranolol in patients with cirrhosis, and 2) to analyze the factors that may influence this response. METHODS: Hemodynamic measurements were undertaken in 80 patients with cirrhosis before and after receiving propranolol (0.15 mg/kg i.v., n = 60) or placebo (n = 20). RESULTS: No changes were observed in the placebo group. Propranolol lowered (p < 0.01) hepatic venous pressure gradient from 17.6 +/- 3.8 to 14.7 +/- 3.8 mmHg, portal blood flow from 1122 +/- 363 to 897 +/- 332 ml/min and forearm blood flow from 7.52 +/- 3.1 to 6.12 +/- 2.3 ml/min%. Changes in hepatic venous pressure gradient were correlated (p < 0.01) with those of portal blood flow (r = 0.82) and forearm blood flow (r = 0.54). The reduction in hepatic venous pressure gradient was > 20% in 23 patients ("responders"). The accuracy of portal Doppler flowmetry in identifying responders was higher than that of forearm plethysmography (88.3 vs. 68.3%, p < 0.05). Multivariate analysis proved that previous variceal bleeding was the only factor independently associated with a lack of response to propranolol (relative risk 3.42, 95% CI 1.5-7.4, p < 0.01). Hepatic venous pressure gradient reduction by propranolol was higher in non-bleeders than in bleeders (-19.9 +/- 9.4 vs. -11.3 +/- 8.6%, p < 0.01). CONCLUSIONS: Portal Doppler ultrasound can be used as a reliable surrogate indicator of the hepatic venous pressure gradient response to acute propranolol administration. In addition, our study indicates that this response is mainly influenced by previous variceal hemorrhage.

Adrenergic beta-Antagonists↗
PubMed1997

Photosensitive polyurethanes applied to the development of CHEMFET and ENFET devices for biomedical sensing.

Chemical microsensors based on ion-selective field effect transistor (ISFET) transducers with ion-selective and enzymatic membranes have been fabricated. In this case, photolithographically patterned membranes based on acrylated urethanes have been developed and applied onto the gate area of ISFET chips. Aliphatic urethane diacrylate has been used for K+ and NH+4 membranes, while a photocurable hydrogel formulation based on other type of acrylated urethane has been optimized for urea-FET sensors. Resulting potassium and ammonium sensors show similar performances to those found when PVC membranes are employed. An integrated packaging process for ISFET-based sensors has been developed giving the possibility of carrying out most of the encapsulation on wafer level. For this purpose, a photocurable polyurethane encapsulant formulation has been optimized to be microstructured by photolithography. Finally, a preliminary study of biocompatibility of photosensitive formulations containing urethane oligomers has been performed in order to examine future applications in biomedical and clinical analysis.

Biosensing Techniques↗
PubMed1997

Use of subdiaphragmatic bupivacaine instillation to control postoperative pain after laparoscopic surgery.

Although postoperative pain has been reduced significantly since the advent of laparoscopic surgery, many patients still complain of moderate abdominal and shoulder pain during the first 48 to 72 h after surgery. In this study, the effect of subdiaphragmatic instillation of bupivacaine after laparoscopic cholecystectomy was investigated. The evaluation of postoperative pain was done according to a numerical verbal scale and the dose of analgesia required. The results showed a considerable reduction of postoperative pain during the first 48 h after surgery in patients who received bupivacaine instillation. Although the literature shows certain controversy as to the effects of similar methods, our study concludes that instillation of a long-acting anesthetic, such as bupivacaine, into the subdiaphragmatic space after laparoscopic procedures is effective in postoperative pain reduction.

Adult↗
PubMed1997

[Contribution of thalamic somatosensory evoked potentials to stereotaxic thalamometry].

INTRODUCTION: In order to use short latency somatosensory thalamic evoked potentials (PES) to locate therapeutic targets in functional surgery, thalamic PES were recorded during stereotactic thalamotomy in 25 patients with Parkinson's disease, using a concentric bipolar semi-micro-electrode, 4 mm in diameter. In the 72 trajectories planned. 628 registers were made, obtaining 314 PES in 55 trajectories. These recordings were divided into 5 groups, according to the electrical variables evaluated in each case (absolute latency, inter-peak latency, absolute amplitude and number of phases). MATERIAL AND METHODS: The electrophysiological characteristics of the PES groups obtained, and the spatial representation of these in a tridimensional system of coordinates, is shown. We analyze the sequence of the groups of potentials in each of the trajectories followed. CONCLUSIONS: We consider that the limit between adjacent nuclear edges, ventral intermediate (Vim)-ventro-caudal (Vc), may be represented by the transition of potentials in group 1 to potentials in group 4 and/or potentials of group 3 to those of group 2. This study shows that thalamic PES are useful for locating targets during stereotactic thalamotomy.

Adult↗
PubMed1997

[Historical cohort study on bacterial pneumonias as predictors of the progression of the human immunodeficiency virus disease].

BACKGROUND: Recognition of the importance of bacterial pneumonias in the context of HIV infection has continuously grown throughout the pandemia. It has recently been suggested that these may be predictors of progression of the disease. PATIENTS AND METHODS: The evolution of an historic cohort of patients with HIV infection who were studied in 1989 with pneumonia regarding the presentation of AIDS or death was investigated. A control cohort was established, being age matched for sex, CD4 lymphocyte count, previous HIV disease and the use of zidovudine. Kaplan-Meier curves of survival without AIDS were made and compared by the logarythmic range test. Other predictors of progression were studied by the Cox models. RESULTS: Forty-nine patients were studied in each group, with a total of 121 and 153 patients/year of follow up. Final events were counted in 33 and 27 cases, respectively (p = 0.11). The relative risk of progression was 1.55 (confidence interval of 95%, 0.93 to 2.56) for the group of pneumonias. The estimated relative risk (hazard) performed by a Cox model of proportional risks was however 1.85 (confidence interval of 95%: 1.05 to 3.25, p < 0.05) when the lymphocyte count adjustment was carried out according to the real values rather than by categories. CONCLUSIONS: The results of this historic cohort study support the existence of an association between history of bacterial pneumonia and the risk of HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Human granulocytic ehrlichiosis: a case series from a medical center in New York State.

BACKGROUND: Human granulocytic ehrlichiosis (HGE) is a newly described illness with few reports in the literature. OBJECTIVE: To describe the clinical and laboratory feature of HGE. DESIGN: Case series. SETTING: Tertiary care facility in New York State. PATIENTS: 18 adult patients with HGE. MEASUREMENTS: Epidemiologic, clinical, and laboratory features; treatment; and outcome of patients with HGE. RESULTS: Patients presented with such symptoms as fever (94%) and myalgia or arthralgia (78%). Thirteen patients (71%) recalled being bitten by a tick before onset of symptoms. Leukopenia or thrombocytopenia was seen in 82% of patients, and abnormal liver enzyme levels were seen in 81%. Results of polymerase chain reaction were positive in 9 of 12 patients (75%); morulae were seen in 3 of 12 patients (25%); and the agent that causes HGE was cultured from 2 patients. All but one patient (94%) developed antibodies to Ehrlichia equi. Five patients (28%) were briefly hospitalized, and none died. All patients were successfully treated with doxycycline. CONCLUSIONS: The illness associated with HGE in these patients from the northeastern United States was more mild than that originally described in reports of HGE in the midwestern United States.

Adult↗
PubMed1996

Overexpression of the 67-kD laminin receptor correlates with tumour progression in human colorectal carcinoma.

The high affinity 67-kD laminin receptor (67LR) is a cell surface protein whose expression is increased in a number of human carcinoma models. To date, 67LR expression in colorectal carcinomas has been examined in a small number of cases. 67LR expression has been immunohistochemically analysed in a large series of human colorectal neoplasms, using the MLuC5 monoclonal antibody. The study included 59 samples of non-neoplastic mucosa, 45 polyps (11 hyperplastic, 34 adenomas), 196 carcinomas, and lymph node metastases of 87 carcinomas. Epithelial cells of normal mucosa and hyperplastic polyps were negative or showed weak positivity in the paranuclear and apical areas of the cytoplasm. In adenomas and carcinomas, the staining was stronger, with a membranous or cytoplasmic pattern. The expression of 67LR correlated significantly with the progression from normal mucosa (22 per cent) to adenoma (44 per cent), carcinoma (61 per cent), and lymph node metastasis (75 per cent) (P < 0.0001). Expression of the laminin receptor showed a tendency to be more frequently positive in advanced stage (III+IV; 67 (III+IV; 67 per cent) when compared with early stage (I+II) carcinomas (54 per cent). The difference, however, was not statistically significant (P = 0.058). In addition, 14 out of 28 (50 per cent) primary carcinomas without 67LR expression became positive in lymph node metastases, while most (86 per cent) of the MLuC5-positive primary carcinomas were also immunoreactive in metastases. In conclusion, these results indicate that 67LR is up-regulated in the progression of human colorectal carcinomas and may play a role in the local and metastatic progression of these tumours.

Adenocarcinoma↗
PubMed1996

Stunned myocardium after thrombolytic treatment. Identification by dobutamine echocardiography and role of the residual stenosis in the infarction artery.

UNLABELLED: The aim of this study was to identify post-thrombolysis stunned myocardium using low dose (10 micrograms/kg/min) dobutamine echocardiography, and to elucidate the role of the residual stenosis in the infarction artery in wall motion recovery. Forty-seven consecutive patients treated with thrombolytic agents for a first non-complicated myocardial infarction were included. An early dobutamine echocardiogram was performed 7 +/- 2 days after thrombolysis to calculate a wall motion score index at baseline and with dobutamine. A late resting echocardiogram 36 +/- 7 days and a coronariography 41 +/- 8 days after thrombolysis were also performed. In 12 patients no baseline regional dysfunction was observed in the early echocardiogram (Group I), whereas 35 patients (Group II) presented regional dysfunction which improved with dobutamine in 11 cases (Group IIA), but not in 24 (Group IIB). Maximum creatine kinase peak was smaller in Group I (458 +/- 162, P < or = 0.01) and in Group IIA (931 +/- 593, P < or = 0.05) than in Group IIB (1547 +/- 886). Late resting echocardiogram was performed in 44 patients: all 12 from Group I, 10 from Group IIA and 22 from Group IIB; all patients from Group I persisted with normal wall motion, while the baseline score index improved in seven patients (70%) from Group IIA vs. three patients (14%) from Group IIB (P < or = 0.01). Quantitative angiographic parameters in the infarction artery failed to differentiate the subgroup of patients in whom wall motion improved in the late echocardiogram. By simple regression, smaller creatine kinase peak (P < or = 0.05) and a positive response to dobutamine in the early echocardiogram (P < or = 0.001) correlated with wall motion recovery, but the minimum lumen diameter in the infarction artery did not correlate; by multiple logistic regression, only a positive response to dobutamine in the early echocardiogram independently predicted late wall motion improvement (P < or = 0.001). CONCLUSIONS: (1) Low dose dobutamine echocardiography early after thrombolytic treatment identifies dysfunctional myocardium with potential late spontaneous improvement (stunned myocardium). (2) Myocardial stunning tends to occur in small infarctions. (3) Late wall motion improvement can occur despite severe residual stenosis in the infarction artery.

Anistreplase↗
PubMed1996

Ventricular tachycardia in Duchenne's muscular dystrophy.

We report a case of a 31-year-old man with severe Duchenne's muscular dystrophy and sustained ventricular tachycardia. Serial electrophysiologic studies demonstrated the inefficiency of antiarrhythmic drugs in our patient who died after the implant of an automatic cardioverter defibrillator. A literature review is made.

Adult↗
PubMed1996

Differences in voice quality between men and women: use of the long-term average spectrum (LTAS).

The goal of this study was to determine if there are acoustical differences between male and female voices, and if there are, where exactly do these differences lie. Extended speech samples were used. The recorded readings of a text by 31 women and by 24 men were analyzed by means of the Long-Term Spectrum (LTAS), extracting the amplitude values (in decibels) at intervals of 160 Hz over a range of 8 KHz. The results showed a significant difference between genders, as well as an interaction of gender and frequency level. The female voice showed greater levels of aspiration noise, located in the spectral regions corresponding to the third formant, which causes the female voice to have a more "breathy" quality than the male voice. The lower spectral tilt in the women's voices is another consequence of this presence of greater aspiration noise.

Adult↗
PubMed1996

The long-term average spectrum as a measure of voice stability.

This paper aims at providing a methodological answer to the topic of voice stability. Seventeen experimental subjects read a standard text 5 times during a 2-week period. The data were obtained through the Long-Term Average Spectrum and were analyzed with a twofold procedure: (i) analysis of the absolute energy values at different frequency points throughout the length of the spectrum, and (ii) analysis of the relative values obtained by subtraction of each of two consecutive frequency values analyzed. The results obtained with the first procedure indicate that the differences that exist between the various sessions are centered mainly in the frequencies below 0.6 kHz and in the area of 4 kHz, following a linear tendency. The fact that the differences between sessions disappear when employing relative measures may indicate that the utilization of these measures eliminates the sources of systematic or aleatoric error can be introduced during a recording or in the period of time between two consecutive recording sessions.

Adult↗
PubMed1996

[Cardiac angiosarcoma].

We report a case of a 29-year-old patient with recurrent hemorrhagic pericardial effusion secondary to a right atrial mass detected by transthoracic echocardiography. A more detailed anatomic study was provided by transesophageal echocardiogram and nuclear magnetic resonance imaging. During surgery, a biopsy confirmed the diagnosis of angiosarcoma. We discuss the contribution of echocardiography and other noninvasive methods to evaluate intracardiac tumors. A brief review of treatment and prognosis is made.

Adult↗