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Biomedical subjects

M Mendez

Publications and source records attributed to M Mendez.

67 records · Page 4Linked to original sources
PubMed1981

Long-term results of operations for mitral insufficiency secondary to coronary artery disease.

There are few published reports regarding the long-term results of the operative treatment of significant mitral insufficiency secondary to coronary artery disease. The few available reports deal with mitral replacement and myocardial revascularization. However, we prefer mitral repair to mitral replacement with myocardial revascularization. Eighty-seven patients were operated upon with ejection fractions between 0.1 and normal. In 16 patients it was necessary to replace the mitral valve; however, the valve was repaired in the remaining 71 patients. By actuarial curve the survival rate at 9 years was 60 percent for the entire series, and 18 percent in the 16 patients with mitral valve replacement and revascularization. This contrasted with a 73 percent survival rate for those patients with repair of the mitral valve and revascularization. We feel strongly that if repair is done properly, it is far superior to mitral valve replacement for the patient with mitral insufficiency secondary to coronary artery disease.

Adult↗
PubMed1980

Failure of intravenous and intrathecal cytarabine to modify central nervous system IgG synthesis in multiple sclerosis.

To study the nature of the multiple sclerosis (MS) central nervous system (CNS) immune reaction, cytarabine (ara-C) was administered intravenously to three patients and intrathecally to another seven. Although intravenous administration severely suppressed circulating leukocytes derived fom the bone marrow, there was no change in de novo CNS IgG synthesis (rate or presence of CSF IgG oligoclones). Therefore, the MS CNS immune reaction can persist in the presence of severe granulocytopenia and severe monocytopenia of one to two weeks' duration. In four patients who were given ara-C intrathecally, cytotoxic levels (> 10 micrograms/ml) were present for a least 24 hours. A brief elevation in CSF albumin indicated transient damage to the blood-brain barrier. Leukopenia did not result in the seven patients treated intrathecally, and de novo CNS IgG synthesis did not change or was transiently increased. Assuming that cytotoxic levels in CSF diffused to the CNS sites responsible for synthesizing IgG, results indicate that CNS IgG synthesis does not depend on in situ rapid turnover of immune cells. None of the ten patients demonstrated neurological improvement or persistent adverse effects.

Adult↗
PubMed1980

Multiple sclerosis de novo CNS IgG synthesis: effect of ACTH and corticosteroids.

ACTH gel and corticosteroids were given to 28 clinically definite multiple sclerosis (MS) patients to determine whether de novo central nervous system (CNS) IgG synthesis (rate and cerebrospinal fluid [CSF] IgG oligoclonal bands) could be eradicated. The most effective treatments were ACTH gel and ACTH gel followed by prednisone, all 11 patients had a significant reduction in rate (p < 0.05), which became normal in eight patients (< 3.3 mg per day). In order of effectiveness, the other drugs used were: dexamethasone or prednisone given orally, and hydrocortisone administered intrathecally. For most treatments, reduction of the rate of CNS IgG synthesis occurred within days and persisted for months after cessation of treatment. The MS CNS immune reaction was not eradicated when IgG synthesis rate became normal, because CSF IgG oligoclonal bands persisted. None of the chronic progressive, severely disabled patients demonstrated significant change in neurologic function or persistent adverse effects.

Adrenal Cortex Hormones↗
PubMed1978

Resection of postinfarction left ventricular aneurysm with and without revascularization.

Twenty-four patients had resection of their ventricular aneurysm and 29 had resection plus revascularization. Sixty percent of the patients received no blood in the heart lung machine during surgery or at any time during hospitalization. One of 24 patients with ventricular resection and two of 29 patients with resection plus revascularization died during hospitalization, for an overall mortality of 5.7%. Fifty of the 53 patients had an ejection fraction of 0.4 or less and 23 of these had an ejection fraction of 0.2 or less. Survival rate was 75.5% at four years for all 53 patients compared to only 12% of patients alive at five years with medical treatment. For the patient with a large ventricular aneurysm, resection and myocardial revascularization can be performed with a low risk even for the patient with poorly functioning residual myocardium.

Adult↗
PubMed1978

Surgery for mitral and tricuspid insufficiency associated with secundum atrial septal defect.

Pure mitral insufficiency associated with secundum atrial septal defect is not an unusual finding. Thirteen patients with significant mitral insufficiency and an associated secundum defect were operated upon. Two of these patients also had severe tricuspid insufficiency. The mitral valve was repaired in 12 patients and replaced in one. The tricuspid valve was reapired in the two patients with associated tricuspid insufficiency. There were two early deaths due to mediastinitis and one late death due to a cerebral embolus in the only patient who had valve replacement; this patient died 3 years after the operation. It is concluded that mitral and tricuspid valve repair should be performed for patients with significant mitral and tricuspid insufficiency associated with atrial septal defect of the secundum variety. Replacement of the values should be avoided if possible.

Adolescent↗
PubMedDate not supplied

Specific inhibitors of pyroglutamyl peptidase I and prolyl endopeptidase do not change the in vitro release of TRH or its content in rodent brain.

Pyroglutamyl diazomethyl ketone and N-benzyloxycarbonyl prolyl prolinal, specific inhibitors of pyroglutamyl peptidase I and prolyl endopeptidase respectively, were used to study the possible role of these enzymes in the regulation of thyrotropin releasing hormone turnover. In vitro thyrotropin releasing hormone release by male rat hypothalamic slices was studied. Combined in vitro treatment with 10(-5)M of both inhibitors totally inhibited both enzymatic activities. The treatment did not affect basal or 56 mM K+ induced thyrotropin releasing hormone release or thyrotropin releasing hormone levels in slices. Repeated combined intraperitoneal injections of the two inhibitors for up to 12 hours produced a 70%-95% reduction in mouse brain pyroglutamyl peptidase I specific activity and a 65%-85% reduction in prolyl endopeptidase specific activity. Thyrotropin releasing hormone levels were unaffected by this treatment in all regions tested. The data suggest that these two enzymes are not involved in the intra- or extracellular control of thyrotropin releasing hormone levels in brain or hypophysis.

Aminopeptidases↗
PubMedDate not supplied

Regional distribution of in vitro release of thyrotropin releasing hormone in rat brain.

To increase our knowledge of the TRH functions in brain and the processes of TRH compartmentalization and release, we studied the in vitro release of endogenous TRH in different brain areas. We also determined the correlation between TRH levels and release under both basal and stimulated conditions. TRH concentration was measured in tissues and media by specific radioimmunoassay. TRH-like material detected in olfactory bulb and hypothalamic incubates (basal or K+ stimulated) were shown to be chromatographically identical to synthetic TRH. Different brain regions showed high variability in the basal release of TRH (1-20% of tissue content). This suggests the existence of different pools. The response to depolarizing stimulus (56 mM K+) was significant only in the following regions: median eminence, total hypothalamus, preoptic area, nucleus accumbens-lateral septum, amygdala, mesencephalon, medulla oblongata and the cervical region of the spinal cord. These regions have been shown to contain a high number of receptors, a high concentration of TRH nerve endings and are susceptible to TRH effects. These results support the hypothesis that TRH functions as neuromodulator in these areas.

Animals↗
PubMedDate not supplied

Retroperitoneal feeding tube for peritoneal dialysis patients.

Treatment of the cachetic, hypoalbuminemic, peritoneal dialysis patient represents a vexing patient management problem. In the past, when the cause of inanition was intractable vomiting secondary to gastroparesis, the solution was to create a transperitoneal percutaneous enterogastrostomy. This endoscopic procedure bypassed the nonfunctioning stomach and allowed for adequate nutrition. When hypoalbuminemia is present, the patient is predisposed to the possible complications of peritoneal sepsis, dialysis fluid leak, and wound dehiscence. The authors report a unique, enteric feeding tube that is a solution to the problem of continuing adequate, complication-free dialysis in a cachetic, hypoalbuminemic peritoneal dialysis patient with no available site for either temporary or permanent hemodialysis vascular access. The procedure does not violate the peritoneal cavity and has proven to be effective, acceptable to the patient, apparently safe, and easy for both staff and patient use.

Cachexia↗
PubMedDate not supplied

Route learning performance in Alzheimer disease patients.

OBJECTIVE: To examine performance on an objective measure of route learning in Alzheimer disease (AD) patients. BACKGROUND: Topographic disorientation (TD) is a common problem among AD patients. The underlying cognitive deficits that contribute to TD in AD patients are not well understood. METHOD: This study examined 19 healthy older individuals (controls) and 16 AD patients who were administered a comprehensive neuropsychological battery along with a novel Route Learning Test (RLT). Areas assessed included incidental learning, spatial relations. recall of the walking route, and recognition of landmarks. RESULTS: Despite comparable performance on basic visuospatial ability measures, AD patients performed significantly worse than controls on the RLT and evidenced poor incidental learning for environmental details. A measure of egocentric and allocentric orientation ability was the best predictor of RLT performance in AD patients. Among RLT subtests, AD patients performed best on recognition of landmarks compared with recognition and recall of spatial layout or recognition of incidental items in the environment. CONCLUSIONS: Our findings suggest that poor performance on the RLT in AD patients is characteristic of poor spatial orientation or spatial reasoning. Therefore, episodes of TD in AD patients may occur secondary to poor spatial orientation.

Aged↗