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Biomedical subjects

J A Alvarez

Publications and source records attributed to J A Alvarez.

At least 37 records · Page 2Linked to original sources
PubMed1996

Primary intrinsic brainstem oligodendroglioma in an adult. Case report and review of the literature.

Primary intrinsic oligodendrogliomas of the brainstem are exceedingly unusual. The authors report the case of an intraaxial brainstem oligodendroglioma in an adult. In an extensive review of oligodendrogliomas, only six (0.4%) of 1593 cases recorded could be identified as intrinsic brainstem tumors. Five of these cases were found in children. This report documents a 25-year-old woman with a pontomedullary oligodendroglioma. An analysis of the world literature on this tumor type finds that posterior fossa oligodendrogliomas present at an earlier age and appear to be more aggressive biologically than their supratentorial counterparts. The overall prognosis for patients harboring an intrinsic brainstem oligodendroglioma remains unclear, with significant variability between patients.

Adult↗
PubMed1995

Sensitivity of monoclonal antibodies to carcinoembryonic antigen, tissue polypeptide antigen, alpha-fetoprotein, carbohydrate antigen 50, and carbohydrate antigen 19-9 in the diagnosis of colorectal adenocarcinoma.

PURPOSE: This study was designed to establish the sensitivity of monoclonal antibodies to carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), tissue polypeptide antigen (TPA), carbohydrate antigen 50 (CA 50), and carbohydrate antigen 19-9 (CA 19-9) and the efficacy of the joint determination of several tumor markers, as well as the dynamics of postoperative normalization of each marker in the absence of recurrence. MATERIALS AND METHODS: A prospective study was carried out in 100 patients subjected to surgical resection of colon adenocarcinoma. Serum concentrations of these markers were determined the day before surgery and seven days, two months, and six months after surgery. RESULTS: The results demonstrate that sensitivity increased as the disease spread and that CA 19-9 was the most sensitive tumor marker. The rate of false negatives was 40 percent for Dukes Stage A lesions, 19 percent for Dukes Stage B, 7 percent for Dukes Stage C, and 0 percent for Dukes Stage D. Determination of two markers (CA 19-9 and CEA) provided the greatest sensitivity in Stages A and D tumors (60 percent and 100 percent, respectively); the incidence did not change when measurements of other antigens were associated. For Stages B and C, determination of at least three markers was necessary, the association of CEA, TPA, and CA 19-9 being that which showed the greatest sensitivity, 78 percent and 91 percent, respectively. CONCLUSIONS: It would be advisable to include monoclonal antibody determination of CEA, TPA, and CA 19-9 in the diagnosis of adenocarcinoma, despite the fact that ultimate sensitivity will depend on the degree of tumor extension or on the presence of metastasis.

Adenocarcinoma↗
PubMed1995

[Carcinosarcoma of the gallbladder].

The authors present a case of carcinosarcoma of the gallbladder, discussing its possible histological origin, clinical picture, and recommended therapeutic approaches. Only 30 cases have so far been reported. The case described was seen because of a painless large volume mass in the right hypochondrium. She was surgically treated with a complete resection of the gross tumor including a portion of choledochus, followed by chemotherapy. The survival was of 20 months.

Carcinosarcoma↗
PubMed1993

Use of multiplex polymerase chain reaction-based assay to conduct epidemiological studies on bovine hemoparasites in Mexico.

A study was conducted to test the applicability of a Polymerase Chain Reaction (PCR)-based approach for the simultaneous detection of the bovine hemoparasites Babesia bigemina, B. bovis and Anaplasma marginale. Bovine blood samples from cattle ranches of a previously determined enzootic zone in the Yucatan Peninsula of Mexico, were collected from peripheral blood and processed for PCR analysis. Blood samples were subjected to DNA amplification by placing an aliquot in a reaction tube containing oligonucleotide primers specific for DNA of each hemoparasite species. The PCR products were detected by Dot-Blot nucleic acid hybridization utilizing nonradioactive, species-specific, digoxigenin PCR-labeled DNA probes. Four hundred twenty one field samples analyzed by the multiplex PCR-DNA probe assay showed 66.7%, 60.1% and 59.6% prevalence rates for B. bigemina, B. bovis and A. marginale, respectively. The multiplex PCR analysis showed that animals with single, double or triple infection could be detected with the parasite specific DNA probes. The procedure is proposed as a valuable tool for the epidemiological analysis in regions where the hemoparasite species are concurrently infecting cattle.

Animals↗
PubMed1992

Evaluation of a colorimetric Babesia bigemina-DNA probe within an epidemiological survey.

An epidemiological survey was conducted in southeast Mexico, in an effort to establish the serological reactivity and carrier status to Babesia bigemina of an indigenous cattle population. The prevalence was obtained through the Indirect Fluorescent Antibody Test (IFAT), using an in vitro culture-derived B. bigemina antigen. A specific, digoxigenin-coupled, approximately 6 Kb B. bigemina-DNA probe (BBDP), was used to indicate the presence of the parasite. Serum samples from 925 animals of all ages, were obtained within the three regions (I, II, III) of the state of Yucatan and tested by IFAT. In addition, whole blood samples drawn from 136 of the same animals of region II were analyzed using the BBDP. Positive IFAT (IFAT+) reactions were observed in 531 sera for a 57% overall prevalence. Regional values were: I = 157+ (56%), II = 266+ (68%) and III 108+ (42%). Only 32 (23%) of the blood samples tested with BBDP showed distinctive hybridization signal, in contrast with 100 (73%) IFAT+ animals. The response distribution for IFAT vs. BBDP was: +/+ 23, +/- 77, -/+ 9 and -/- 27 respectively. It was found that the analytical sensitivity of BBDP appears to be low for its utilization in widespread epidemiological surveys. It was considered, however, that the colorimetric probe might be useful to safely detect transmission prone carriers, since it is able to detect parasitemias as low as 0.001%.

Age Factors↗
PubMed1992

Localization of basic fibroblast growth factor and vascular endothelial growth factor in human glial neoplasms.

Fibroblast growth factors (FGFs) are widely recognized as a family of molecules that can influence cell proliferation and tissue neovascularization. Although the basic form of FGF (bFGF) has been found to enhance the growth of primary cell cultures made from human glial tumors, its exact role in vivo has been unclear. Likewise, vascular endothelial growth factor (VEGF) is a newly discovered addition to the growing list of angiogenic factors but, unlike bFGF, VEGF has a unique specificity for endothelial cells and possesses the properties required for secretion. In this study, we localized both basic FGF and VEGF in human gliomas to assess their possible role in the pathogenesis of these neoplasms. Retrospective analysis was performed using glial neoplasms that were fixed in 10% neutral buffered formalin and embedded in paraffin. The immunocytochemical procedures were performed using specific polyclonal antibodies raised against the amino terminus of bFGF and VEGF, respectively. Immunoreactive (IR) basic FGF was localized in normal, reactive, and neoplastic astrocytes as well as selected populations of normal neurons. IR VEGF, in contrast, was present primarily in neurons of normal brain, but was also found in both reactive and neoplastic astrocytes. In adjacent 4-microns tissue sections, strong immunoreactivity for VEGF and bFGF was found within the same populations of cells. In areas of endothelial proliferation, the strongest immunoreactivity for both growth factors was found within large anaplastic astrocytes that surrounded abnormal blood vessels. Our data support the hypothesis that VEGF may complement the actions of basic FGF in glial neoplasia.

Astrocytoma↗
PubMed1991

Transseptal left heart catheterization: usefulness of the intracavitary electrocardiogram in the localization of the fossa ovalis.

One of the major difficulties in left heart catheterization through the interatrial septum is to ensure that the Brockenbrough needle tip is correctly laid on the fossa ovalis floor (FOF), which is the only area where the puncture must be done. The difficulties may be enhanced in patients with atrial enlargement and subsequent distortion of the anatomical structures. In order to reduce the hazards of the septal puncture, an electrocardiographic mapping of the right atrial endocardium was performed using the Brockenbrough needle as an exploratory electrode in a group of 20 patients. When the tip of the needle was laid against the FOF, the endoatrial electrocardiogram (EAE) registered a slight or no injury curve, even when the pressure was tight enough to perforate the septum. On the contrary, the pressure on any other area of the muscular septum or atrial walls elicited a bizarre monophasic injury curve. The peculiar electrocardiographic response of the FOF to the pressure exerted by the Brockenbrough needle tip was a valuable aid to identify the area where the transseptal puncture must be done. In addition, the sudden changes in the P wave morphology immediately after the septal perforation, provided the first clue that the left atrium has been reached.

Animals↗
PubMed1990

[Salmonella enterica in the Avilés health district (Asturias). Microbiological, clinical, and epidemiological aspects].

The results of the follow up of the Salmonella enterica infections seen in the Hospital San Agustin in Avilés (Asturias) from 1984 through 1987 are reported. The incidence was 19.49% of the overall number of fecal cultures and 0.47% of the overall number of blood cultures. 326 patients were involved: acute gastroenteritis (314 cases, with bacteremia in 10), typhoid fever (7 cases) and other infections (5 cases); 172 patients required hospital attention and 115 antimicrobial therapy. The morbidity rate was 47.94 per 10(5) and 44 outbreaks were recorded. 19% of strains were resistant to antibiotics, particularly Typhimurium and Virchow serotypes.

Adolescent↗
PubMed1989

Acute arsenic intoxication.

The diagnosis of acute arsenic poisoning should be considered in any patient presenting with severe gastrointestinal complaints. Signs and symptoms include nausea, vomiting, colicky abdominal pain and profuse, watery diarrhea. Hypotension, fluid and electrolyte disturbances, mental status changes, electrocardiographic abnormalities, respiratory failure and death can result. Quantitative measurement of 24-hour urinary arsenic excretion is the only reliable laboratory test to confirm arsenic poisoning. Treatment includes gastric emesis or lavage, chelation therapy, electrolyte and fluid replacement, and cardiorespiratory support.

Acute Disease↗
PubMed1986

Abdominoscrotal hydrocele.

Abdominoscrotal hydrocele is a very rare finding, especially in infants. The authors describe the case of a 7-month-old boy presenting an abdominoscrotal mass, the diagnosis of which was made by sonography and which was excised totally through an extensive inguinal incision.

Abdomen↗
PubMed1984

Spontaneous hematomas caused by microangiomatosis of the basal ganglia. Presentation of two cases in the newborn period.

We present 2 cases of tumors of the gray basal nuclei with intraventricular hemorrhage and secondary hydrocephalus. Because of the patients' ages, the absence of traumatic antecedents and the angiographic characteristics, the findings were diagnosed as gliomas. In both cases, the existence of hematomas provoked by microangiomatosis was proved after the operation. The differential diagnostic between these two entities is discussed.

Angiomatosis↗