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Biomedical subjects

M Mendez

Publications and source records attributed to M Mendez.

At least 55 records · Page 3Linked to original sources
PubMed1990

Development of a somatic cell hybrid mapping panel and molecular probes for human chromosome 3.

A somatic cell hybrid mapping panel and molecular probes have been developed for human chromosome 3. This panel defines 11 regions for the short and long arms of the chromosome. Four hundred thirty-two probes have been mapped using these hybrids. One hundred thirty-one of these probes were derived from EcoRI and HindIII flow-sorted libraries. The remaining 301 probes were isolated from NotI boundary and random (partial MboI) libraries constructed from a hybrid that provided a relative enrichment in 3p DNA sequences. For some regions of the chromosome, significant differences in the distribution of probes were noted. This was observed for both the unique sequence flow-sorted and NotI probes. These differences are in agreement with previous suggestions that Giemsa light bands are GC-rich, and therefore gene-rich (especially housekeeping genes), and that the Giemsa dark bands may contain DNA that is more highly condensed. The isolation of probes from different types of libraries, or by different screening strategies, appears to reduce deficiencies that might arise from the use of probes derived with a more limited approach. These hybrids and probes should facilitate the construction of physical and genetic linkage maps to identify various disease loci involving chromosome 3.

Animals↗
PubMed1989

Tricuspid regurgitation associated with mitral valve disease: repair and replacement.

Between January 1975 and June 1988, 156 patients with combined mitral and tricuspid valve disease underwent mitral and tricuspid valve repair or replacement. There were 127 (81%) patients with tricuspid valve repair and 29 (19%) patients with tricuspid valve replacement. Hospital mortality was 14% and was strongly influenced by preoperative pulmonary hypertension (systolic pressure greater than 65 mm Hg) and poor left ventricular function (ejection fraction less than 0.4). Five-year survival for the entire series was 57% +/- 5%; 12-year survival was 44% +/- 9%. Ejection fraction was the only age-adjusted risk factor for long-term survival. Of the patients who underwent tricuspid annuloplasty, 91% +/- 4% were free from reoperation after 10 years, indistinguishable from valve replacement (90% +/- 7%). Our tricuspid annuloplasty is simple and effective, and exhibits excellent long-term durability as well as immediate hemodynamic improvement.

Adolescent↗
PubMed1989

Pyroglutamyl peptidase II inhibition specifically increases recovery of TRH released from rat brain slices.

Pyroglutamyl peptidase II (EC 3.4.19-) is a highly specific membrane-bound thyrotropin releasing hormone (TRH) degrading enzyme. To study the functional significance of pyroglutamyl peptidase II in TRH degradation, we synthesized the reversible inhibitor N-1-carboxy-2-phenylethyl (Nimbenzyl)-histidyl-beta-naphthylamide (CPHNA). CPHNA inhibited the enzyme with a Ki of 8 microM, but had no effect no TRH receptors or no prolyl endopeptidase (EC 3.4.21.26). It weakly inhibited cytosolic pyroglutamyl peptidase I (EC 3.4.19.3). CPHNA at a concentration of 10(-4) M increased both the basal and potassium stimulated recovery of TRH released from hypothalamic slices by approximately two-fold. An even higher recovery was observed in slices from brain regions with relatively high levels of pyroglutamyl peptidase II. CPHNA had no effect on the basal recovery of gamma-aminobutyric acid or Met-enkephalin released from brain slices but decreased the potassium stimulated recovery of both Metenkephalin and gamma-aminobutyric acid. These data further support the involvement of pyroglutamyl peptidase II in the extracellular inactivation of brain TRH.

Aminopeptidases↗
PubMed1988

Alzheimer's disease and Parkinson's disease: comparison of speech and language alterations.

Speech and language alterations were assessed in 51 patients with Parkinson's disease (PD) and 10 patients with dementia of the Alzheimer type (DAT). Thirty-five of the PD patients had no evidence of intellectual impairment on a conventional mental status questionnaire and 16 of the PD patients had dementia syndromes of comparable severity to the DAT patients. DAT produced significantly greater language disturbances, including anomia, decreased information content of spontaneous speech, and diminished word list generation. PD patients had significantly decreased phrase length, impaired speech melody, dysarthria, and agraphia. The results suggest that the dementia of PD is distinguishable from that of DAT:PD patients have prominent motor speech abnormalities, whereas DAT patients exhibit more profound language alterations.

Aged↗
PubMed1987

Regional distribution of the membrane-bound pyroglutamate amino peptidase-degrading thyrotropin-releasing hormone in rat brain.

The brain regional distribution of membrane-bound pyroglutamate aminopeptidase-degrading thyrotropin-releasing hormone (TRH) in rat was studied using a specific radiometric assay. The distribution was not homogeneous: a 10-fold difference was observed between regions. The highest activity was detected in olfactory bulb while the lowest was in the cervical part of spinal cord. There was no correlation with the regional distribution of enzyme activity vs TRH levels, previously reported TRH receptors or in vitro TRH release. The differential distribution of this enzyme is consistent with the hypothesis that it is responsible for extracellular degradation of neuroactive peptides.

Aminopeptidases↗
PubMed1986

Mitral valve repair for mitral regurgitation secondary to coronary artery disease.

Mitral regurgitation secondary to ischemic heart disease carries a significant mortality in the untreated patient. We report on 141 patients with mitral regurgitation secondary to ischemic heart disease who underwent complete coronary revascularization and correction of mitral regurgitation by either repair (101 patients) or replacement (40 patients). Good long- and short-term palliation was obtained. Left ventricular function (ejection fraction) and recent myocardial infarction were important preoperative determinants of outcome. Repair of the mitral apparatus rather than valve replacement was associated with better long- and short-term survival, especially in the patient with a low ejection fraction. The repaired valve is durable and repair minimizes the risks of thromboembolism, hemolysis, anticoagulation, and intracardiac infection associated with prosthetic valve replacement. Mitral valve repair was possible in 70% of the patients in this series. The benefit to the patient, especially the patient with compromised ventricular function, compensates the surgeon for any extra effort involved in conservation of the mitral apparatus.

Adult↗
PubMed1984

Prolonged high-frequency jet ventilation.

A 26-yr-old woman with bilateral staphylococcal pneumonia developed respiratory failure. Conventional ventilation failed and high-frequency jet ventilation (HFJV) was successfully instituted. Bronchopleural fistulas required prolonged (73 days) support with HFJV. A bronchoscopy performed after 37 days of mechanical support showed no abnormalities. Computed tomography (CT) of the chest demonstrated severe cystic abnormalities. Pulmonary function tests performed 1 and 6 months after recovery showed small-airway dysfunction. HFJV proved safe for prolonged use.

Adult↗
PubMed1982

Treatment of small cell lung cancer with a combination of VP16-213 and cyclophosphamide with cisplatin or radiotherapy.

Fifty five patients with small cell lung cancer with treated with VP16-213 combination chemotherapy regimen in two consecutive series. The first series included 24 patients; 10 with limited and 14 with extensive disease were treated with VP16-213, 120 mg/m2 p.o. daily for 5 consecutive days, Cyclophosphamide 600 mg/m2 i.v. and Cisplatin 80 mg/m2 i.v. with hydratation and manitol induced diuresis. The cycle was repeated every 3 weeks. The second series included 31 similar patients, 16 limited, and 15 extensive disease, treated with VP16-213 at the same dose and Cyclophosphamide at 1,200 mg/m2 i.v. also repeated every 3 weeks; after three cycles the patients were treated with radiotherapy to the primary tumor and regional lymph nodes with 4,000 rads in a split course of three weeks interval, followed by the same combination chemotherapy. Response rate was 75% for the first series with 6 of 24 (25%) of complete responses in four limited and two extensive disease and a median survival time of 24 weeks. In the second series of patients there were 26 of 31 (83.8%) responses with 10 of 31 (32%) complete responses in nine limited and one extensive disease and a median survival time of 33 weeks for responders. Duration of response for complete responders was 36.8 weeks for the first series and 51 weeks for the second. Toxicity was mild and includes nausea and vomiting, myelosupression, alopecia in both series, with one toxic death in the second series. Both regimens are active with a low complete response rate, which was increased in the second series by the addition of radiotherapy, which did not increase overall survival.

Adult↗
PubMed1982

Epstein-barr virus VCA IgM and EBNA IgG antibodies titered by immunofluorescence in microplates. A semi-automated method based on microtiter system.

We describe methods of immunofluorescence in microplates for titration of EBV VCA-IgM and EBNA-IgG antibodies and compare the sensitivity of the methods with glass slides and with microplates, showing the reproducibility of the methods. Results of VCA-IgM and -IgG, EA and EBNA titers obtained in four groups of patients are given, comprising cases of infectious mononucleosis, renal graft recipients, lymphoproliferative diseases and controls.

Acute Disease↗
PubMed1981

Ventricular septal rupture secondary to myocardial infarction. Clinical approach and surgical results.

Twenty-four patients underwent operation for ventricular septal rupture secondary to acute myocardial infarction. There were 14 hospital survivors (58%) and two late deaths (8%). There were eight hospital deaths (62%) of 13 patients referred in cardiogenic shock, but only two deaths (18%) of 11 patients not in shock at time of referral. All 12 current survivors showed clinical improvement, and 11 of them are in New York Heart Association functional class I or II. Eleven patients had bedside catheterization with a balloon catheter and were operated on immediately thereafter, and eight survived (73%) with no late deaths at five years. With formal heart catheterization followed by operation, there were only six survivors of 13 operated on (46%).

Acute Disease↗
PubMed1981

Aortic valve replacement in patients with poor ventricular function-early and late results with long-term follow-up.

A series of 62 consecutive patients with an ejection fraction of 0.4 or less (mean 0.28 with a range from 0.10 to 0.40; 22 between 0.10 and 0.20, 18 between 0.21 and 0.30, and 22 between 0.31 and 0.40) who underwent aortic valve replacement from January 18, 1972 to December 20, 1976 was reviewed. Preoperatively two patients were in Class II, 35 in Class III and 25 in Class IV of the New York Heart Association functional classification (N.Y.H.A.). Thirty-nine patients (Group 1) underwent isolated aortic valve replacement and 23 patients (Group 2) underwent aortic valve replacement with associated procedures including aortocoronary bypass in 15. The operative mortality was 8 percent in Group 1, 17 percent in Group 2, and 11 percent overall. In the group of 15 patients with coronary artery disease, the operative mortality of aortic valve replacement and aorto-coronary bypass was 27 percent. Since January 1974, isolated aortic valve replacement was performed with no operative deaths in 25 consecutive patients in Group 1 including 10 patients with an ejection fraction of 0.2 or less. Five-year survival rates were 70 percent in Group 1, 64 percent in Group 2 and 68 percent overall. In the 38 currently living patients, 32 showed clinical improvement and 27 are in Class I or II of N.Y.H.A. In conclusion, isolated aortic valve replacement can be performed with a low mortality and a high survival rate in patients with impaired left ventricular function.

Adult↗