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Biomedical subjects

C Diaz

Publications and source records attributed to C Diaz.

At least 73 records · Page 4Linked to original sources
PubMed1996

Neuropsychiatric Syndromes in Neurodegenerative Disease: Frequency and Signficance.

Neurodegenerative diseases have neuropsychological, neuropsychiatric, and neurological effects manifested as cognitive, emotional, and physical alterations. These primary effects have secondary consequences on activities of daily living, patient and caregiver distress, and quality of life. Neuropsychiatric manifestations are products of brain dysfunction that are associated with institutionalization, vulnerability to abuse by the caregiver, and use of medications and restraints. Behavioral alterations can often be ameliorated by psychotropic drugs, and the effects of medications contribute to understanding the mechanisms of behavioral changes. Allocation of health service resources for dementia patients is partially determined by the neuropsychiatric dimension of these diseases, and the importance of the neuropsychiatric aspects of degenerative disorders has been underemphasized.

Journal Article↗
PubMed1996

After AIDS clinical trial 076: the changing pattern of zidovudine use during pregnancy, and the subsequent reduction in the vertical transmission of human immunodeficiency virus in a cohort of infected women and their infants. Women and Infants Transmission Study Group.

To determine the impact of the AIDS Clinical Trials Group (ACTG) Protocol 076 results on the subsequent use of zidovudine during pregnancy and the transmission rate of human immunodeficiency virus (HIV) in a cohort of mother-infant pairs (Women and Infants Transmission Study), a retrospective analysis was done. Transmission rates were calculated by simple proportion for infants with at least 6 months of follow-up, stratified by date of birth (n = 453 born on or before 1 March 1994; n = 103 born after 1 March 1994). Transmission rates decreased from 19% to 8% (P = .005, Fisher's exact test). Zidovudine use increased during pregnancy (22% vs. 89%) and in newborns (1% vs. 79%). Both cohorts were similar with respect to maternal immunosuppression, mode of delivery, and demographics. In summary, in a perinatal HIV observational study, the release of results of ACTG Protocol 076 was associated with an increase in zidovudine use during pregnancy and a concomitant decline in HIV transmission from mothers to infants.

Adult↗
PubMed1996

Association of maternal drug use during pregnancy with maternal HIV culture positivity and perinatal HIV transmission.

OBJECTIVE: To evaluate the relationship of drug use with maternal HIV culture positivity at delivery and perinatal HIV transmission. DESIGN: Multicenter prospective cohort study. SETTING: Obstetric and pediatric clinics in five cities in the United States. PARTICIPANTS: Five hundred and thirty HIV-infected pregnant women and their infants. MAIN OUTCOME MEASURES: Multivariate logistic regression was used to evaluate the association of 'hard drug' use (one or more of the following: cocaine, heroin/opiates, methadone, injecting drug use) assessed by self-report and urine toxicology with positive maternal HIV culture at delivery and perinatal HIV transmission. RESULTS: Forty-two per cent of women used hard drugs during pregnancy. Increased probability of a positive maternal delivery HIV culture was significantly associated with prenatal hard drug use [odds ratio (OR), 3.08] and maternal cocaine use (OR, 2.98) among HIV-infected women with > 29% CD4+ lymphocytes. After adjusting for maternal culture positivity at delivery, CD4+ lymphocyte percentage and gestational age, significantly greater transmission risk was observed with hard drug use among women with membrane rupture > 4 h. CONCLUSIONS: On the basis of self-report and urine toxicology, overall maternal hard drug use and cocaine use in the WITS cohort were associated with maternal HIV culture positivity at delivery, and maternal hard drug use was associated with perinatal transmission.

Alcohol Drinking↗
PubMed1996

Complications of supraglottic laryngectomy for carcinomas of the supraglottis and the base of the tongue.

The medical records of patients with either a supraglottic carcinoma (n = 193) or a base of tongue carcinoma (n = 56) who underwent a supraglottic laryngectomy were studied. Because of aspiration total laryngectomy was required in 9.8% and 21.4% of patients with supraglottic and base of tongue carcinomas, respectively, being related to locally advanced stage of disease in the base of tongue and to an age older than 65 years in the case of supraglottic carcinomas. The non-decannulation rates were 23.8% and 50% in supraglottic and base of tongue tumours respectively. Post-operative radiotherapy did not influence the decannulation rate, but advanced local disease and age did. Post-operative mortality in the first month after the operation was 2.6% in supraglottic tumours and 3.6% in base of tongue tumours.

Adult↗
PubMed1996

Primary intraosseous meningiomas.

PURPOSE: A retrospective study was performed to evaluate the clinical, radiological and histological findings of 14 intraosseous meningiomas. MATERIAL AND METHODS: 14 histologically proved intraosseous meningiomas were studied with plain skull film and CT. Pathological records were reviewed. RESULTS: We found 9 calvarial cases and 5 spheno-orbital ones. The most common symptom in the calvarial cases was a lump in the scalp, and in the spheno-orbital lesions it was exophtalmos. Hyperostosis was present in all 5 spheno-orbital cases and in 3 out of the 9 calvarial ones; in the other 6 cases it had a mixed pattern. Enhanced dura was present in 3 calvarial cases and in 2 sphenoidal ones. Dura was involved in 5 cases: 2 with inflammatory changes, 2 with a minimal intradural tumour and one with a subdural tumour. CONCLUSION: CT better detected both the bony reaction and the intraosseous extension of the tumour. The dural changes were not specific of tumoural involvement. The differential diagnosis comprises: fibrous dysplasia, osteoma, blastic metastasis and mainly meningioma en plaque (MEP). Comparing our findings with other series, we noticed that in some cases the term MEP was used for similar cases. As the name MEP is merely descriptive and both entities share a larger number of similarities than differences, we believe that a differentiation between hyperostotic en plaque meningioma and intraosseous meningioma can hardly be made.

Adult↗
PubMed1996

Peritoneal dialysis in liver disorders.

The purposes of this paper is to review the specific role of peritoneal dialysis (PD) in patients with liver disorders. We will pay attention to the confluence of liver diseases and situations for which chronic dialysis treatment is required. Hemodialysis (HD) and peritoneal membranes are safe barriers against the passage of the hepatitis C virus; consequently, while peritoneal effluent or HD ultrafiltrate drained from hepatitis B patients/carriers is infective, that from hepatitis C patients does not appear to present this risk. An important issue is horizontal transmission, which appears to occur with both viruses in HD units, and which is absent in peritoneal dialysis units. The incidence of hepatitis C among continuous ambulatory peritoneal dialysis (CAPD) patients is quite low, while it may reach almost 50%-60% of HD patients in some units. While hepatitis C transmission mechanisms are not completely understood and a vaccine is not available, PD provides some degree of protection when compared with HD, for and-stage renal disease patients. In summary, our experience and that of others, with a total of 19 PD-treated chronic liver disease patients, supports CAPD as the treatment of choice for cirrhotic patients with ascites who require chronic dialysis. Data on peritoneal diffusion of low molecular weight substances revealed a marked increase in most patients. The ultrafiltration capacity was clearly augmented with respect to noncirrhotic patients, making the use of hypertonic bags unnecessary. Hemodynamic tolerance was excellent. Complications and death were mainly related to liver disease complications. Spontaneous bacterial peritonitis (SBP), caused by gram-negative germs, is the most important complication directly related to ascites and may have some points in common with PD-related peritonitis. However, and in contrast to most PD peritonitis, two pathogenetic mechanisms have been suggested for SBP: (1) translocation of bacteria from the gut to the mesenteric lymph nodes, and (2) bacteremia in these patients is secondary to the general abnormal host defense mechanisms. Local factors such as intrahepatic shunting and the impairment of bactericidal activity in ascitic fluid favor the bacteria ascites. The hypothesis of a direct transmural contamination from bowel to ascitic fluid has been relegated to secondary bacterial peritonitis. Would cirrhotic patients with temporal or permanent renal function compromise benefit from peritoneal catheter placement and other PD practices to perform repetitive small ascitic drainages at home? Perhaps the time has arrived when hepatologists and PD nephrologists begin to work shoulder to shoulder in this particular field, as we have a common problem, the peritoneal cavity filled with fluid.

Ascitic Fluid↗
PubMed1995

Adaptive predictive control of dissolved oxygen concentration in a laboratory-scale bioreactor.

We present an algorithm for the adaptive control of dissolved oxygen concentration in a bioreactor, based on the agitation rate. The dynamics are represented by an incremental first-order model with variable dead-time and parameters. These are estimated on-line by a recursive least-squares identification method with a forgetting factor and a constant sensitivity. The model is employed to predict the behaviour of the dissolved oxygen concentration over a finite horizon, using an original method which requires little computation. Then, a Generalized Predictive Control optimisation strategy computes the agitation rate from the predictions and the desired set point, while gradually updating the controller smoothness. This algorithm, which requires little preliminary knowledge, has been implemented on a laboratory-scale fed-batch bioreactor for which the use of conventional controllers showed limited performance, due to the unpredictable and evolutive nature of the dynamics. The new controller proved to be robust and effective over a wide range of operating conditions, while requiring no operator adjustments.

Algorithms↗
PubMed1995

Mycobacterium tuberculosis infection in pregnant and nonpregnant women infected with HIV in the Women and Infants Transmission Study.

BACKGROUND: Prevalence of Mycobacterium tuberculosis (TB) infection and anergy were evaluated in a cohort of pregnant and nonpregnant women infected with the human immunodeficiency virus who were enrolled in a prospective natural history study (the Women and Infants Transmission Study) conducted in New York, NY; Boston and Worcester, Mass; Chicago, Ill; and San Juan, Puerto Rico. METHODS: One hundred eighty-three women (65 pregnant, 118 nonpregnant) were evaluated for TB. The TB history and risk factors were assessed by interview and medical record review. Intradermal skin testing with tuberculin, mumps, and tetanus antigens and CD4+ lymphocyte count were performed. RESULTS: Overall prevalence of TB infection or disease by documented medical history and/or a tuberculin skin test induration of 5 mm or more was 14% (26 of 183). History of TB infection or disease was documented in 11% of the women who were interviewed. Tuberculin and anergy skin test results were evaluable for 124 women; 6% (seven of 124) had tuberculin skin test induration of 5 mm or more, including 11% (five of 46) of the pregnant women who were tested. Induration between 2 and 5 mm was observed in four more women, three of whom were pregnant. Anergy was observed in 42% (52 of 124); prevalence of anergy was higher in nonpregnant women (38 [49%] of 78) than in pregnant women (14 [30%] of 46). While anergy was more common in women with a CD4+ cell count of 0.5 x 10(9)/L or less, 27% of those with a CD4+ cell count of more than 0.5 x 10(9)/L were also anergic. CONCLUSION: These data support current Public Health Service recommendations for tuberculin skin testing in persons infected with the human immunodeficiency virus, and emphasize that evaluation should include pregnant as well as nonpregnant women. The prevalence of anergy does not appear increased in pregnancy in women infected with the human immunodeficiency virus. Health care providers should include tuberculin and anergy skin testing as part of the standard prenatal care for women infected with the human immunodeficiency virus.

Adult↗
PubMed1995

Differential regulation of endogenous endonuclease activation in isolated murine fibroblast nuclei by ras and bcl-2.

Transfection of a murine fibroblast cell line with an activated form of the Harvey ras oncogene conferred sensitivity to apoptosis induced by various agents. This intrinsic sensitivity to apoptosis correlated with the expression of endogenous endonuclease activity in isolated nuclei that was undetectable in the untransfected parental cell line. Subsequent transfection with the human bcl-2 oncogene prevented the morphological and biochemical features of apoptosis in whole cells, although it failed to confer complete protection against cell death. Furthermore, transfection of the bcl-2 oncogene also inhibited the enhanced endonuclease activity in isolated nuclei. Our results indicate that some of the effects of Ha-ras and bcl-2 and potentially other oncogenes, are exerted on the biochemical machinery of apoptosis at the level of the nucleus.

Animals↗
PubMed1995

[Trichoblastoma. A tumor with follicular differentiation].

The purpose of this article is to inform about neoplasms with follicular differentiation, particularly trichoblastoma. In 1970 Headington divided neoplasms of the hair germ (trichogenic tumours) into four groups: purely epithelial without inductive changes (trichoblastomas), mixed epithelial-mesenchymal with inductive changes (trichoblastic fibromas), mixed epithelial-mesenchymal with inductive changes and advanced hair follicle formations (trichogenic trichoblastomas), and predominantly mesenchymal with an abortive dermal hair papilla (trichogenic myxoma). Meanwhile a new classification of neoplasms with follicular differentiation has been presented, according to which every neoplasm with follicular differentiation, benign structure (symmetrical, circumscribed, with vertical growth), and predominance of follicular germinative cells is called a trichoblastoma. Whether this neoplasm is malignant and if so to what degree is under discussion. This classification is gaining in acceptance among histopathologists but has not been accepted in the field of clinical dermatology.

Basal Cell Carcinoma↗
PubMed1995

Seroreversion in human immunodeficiency virus-exposed but uninfected infants.

The goal of this study was to describe seroreversion (SR) in a cohort of human immunodeficiency virus-exposed but uninfected infants. Groups of patients who seroreverted very early or late were examined for salient clinical and immunologic characteristics of the mother or infant. The mean time (+/- s.d.) to seroreversion by enzyme-linked immunoabsorbent assay (ELISA) was 50.1 +/- 14.8 weeks, or 11.6 months (n = 84); the range of times to antibody loss by ELISA was 17.9 to 82.0 weeks. The mean time to seroreversion by Western blot was 68.3 +/- 12.6 weeks, or 15.8 months (n = 51), with a range of 44.9 to 94.1 weeks. Initial anti-human immunodeficiency virus titer as measured by cord blood ELISA optical density (OD) was found to relate significantly to mean time to seroreversion. No relationship to time to seroreversion was demonstrated for gestational age, maternal or neonatal serum immunoglobulin concentrations, maternal CD4 cell counts, maternal alcohol consumption, infantile diarrhea or failure to thrive. The lengthy time to seroreversion seen here demonstrates the 1994 revised Centers for Disease Control and Prevention definition of human immunodeficiency virus infection (based on seropositivity by both ELISA and confirmatory tests persisting beyond 18 months of age) to be accurate in our population. We recommend Western blot testing be used as confirmation for positive ELISAs only after 18 months of age.

AIDS Serodiagnosis↗
PubMed1995

Appearance of drug-resistant tuberculosis in rural Tennessee.

Drug-resistant tuberculosis (DRTB) is a growing national health concern in both urban populations and rural areas and is exacerbated by the growing epidemic of human immunodeficiency virus (HIV) infection. Between 1989 and 1992, 7 cases of DRTB (5 with multidrug-resistance) were diagnosed in an eight-county region of East Tennessee. During 1990 and 1991 alone, 5 of 100 patients with tuberculosis had drug-resistant strains (5%). All 7 patients with DRTB had 100% resistance to isoniazid; 5 also had resistance to streptomycin, 2 to rifampin, and 1 to pyrazinamide and ethambutol. All patients were white, U.S.-born, and without evidence of HIV infection. Contact investigation revealed that more contacts of patients with DRTB (13 of 74, 18%) were infected than were contacts of patients with drug-sensitive tuberculosis (46 of 290, 16%). Our study demonstrates that DRTB is not confined to geographically distinct areas, but may be a subtle and easily missed diagnosis in presumably low-risk rural populations.

Adult↗
PubMed1995

Rapid reocclusion of left primary bronchus by fibrinomucinous cast in a case of large cell lung cancer.

This report describes a case of large cell carcinoma of the lung in a patient whose left primary bronchus became completely occluded by a fibrinomucinous cast that recurred within 24 hours despite extensive lavage and removal of the cast via flexible bronchoscopy. The primary tumor involved the aortopulmonary window and was affixed to the pulmonary artery and the aorta, arising from the left upper lobe and extending to the left primary bronchus. The occurrence of a large fibrinous endobronchial cast removed by flexible bronchoscopy forceps, such as we report here, is extremely rare.

Airway Obstruction↗
PubMed1995

Evaluation of palpable breast masses with 201Tl scintigraphy.

39 female patients (age range: 31-84 years) with palpable breast masses detected by physical examination, underwent 201Tl scintigraphy in order to assess its value in the detection of breast carcinomas and to differentiate them from benign breast masses. Planar images were carried out at 20-30 min and 2-3 h after intravenous administration of 111-185 MBq (3-5 mCi) of 201Tl chloride. In 12 patients single photon emission tomography (SPET) studies were also performed. In 18 patients the scintigraphic studies were positive and in 17 of these cases, breast carcinomas were confirmed. Tumour sizes ranged from 1.3 to 6 cm in diameter. In the remaining patient a false positive result was obtained where there was benign breast change. In three of seven cases, malignant axillary nodes were also detected. All 21 patients with negative scintigraphy had benign breast lesions. There were no differences between images obtained at 20-30 min and 2-3 h or between planar images and SPET studies. In 10 patients there was disagreement between mammography and 201Tl scans. 201Tl scans confirmed the presence of carcinoma in three cases and discarded malignancy in the other six cases. In the remaining case, 201Tl scan was false positive. 201Tl scintigraphy is useful in distinguishing malignant from benign breast masses, even when compared with mammography.

Adult↗