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Biomedical subjects

M Diaz

Publications and source records attributed to M Diaz.

At least 127 records · Page 7Linked to original sources

Compliance measurement in respiratory distress syndrome: the prediction of outcome.

Dynamic compliance (Cdyn) measurements within the first three days of life predicted survival in 60 preterm infants suffering from respiratory distress syndrome. Cdyn was measured in 47 survivors at 2.3 +/- 1.4 days of life and in 13 nonsurvivors on 2.7 +/- 1.7 days. All nonsurvivors died from respiratory failure within the first two weeks of life. Mean Cdyn of the survivors was 0.83 +/- 0.33 ml/cm H2O and of the nonsurvivors 0.35 +/- 0.19 ml/cm H2O (p less than 0.001). Cdyn values below 0.45 ml/cm H2O predicted 11 of 13 deaths in infants, and Cdyn measurements above this value predicted 45 of 47 survivals, with a specificity of 81% and a sensitivity of 89%. Eleven of the survivors, who subsequently developed bronchopulmonary dysplasia (BPD), had a mean Cdyn of 0.56 +/- 0.23 ml/cm H2O. When these infants were matched with infants of comparable weight without evidence of BPD, the BPD group had a significantly lower Cdyn (p less than 0.05). Cdyn measurements during the first three days of life are useful in predicting outcome of respiratory failure secondary to respiratory distress syndrome.

Airway Resistance↗

Gender, sexuality and communication issues that constitute barriers to the use of natural family planning and other fertility awareness-based methods.

Fertility awareness-based methods of family planning are rarely offered through reproductive health services in Latin America, despite evidence that many women use them. Providers state that clients do not want these methods, but provider-bias is evident. Providers overestimate the difficulty of learning and using fertility awareness-based methods, and they underestimate their efficacy. Both providers and clients have difficulty dealing with sexuality (which is central to fertility awareness-based methods). Many providers lack gender sensitivity, 'worsening' the unequal relationship between providers and clients. Experience has shown that when fertility awareness-based methods are well provided, they can have a positive effect on sexuality, self-understanding, and equality in the couple's relationship.

Awareness↗

Maternal blood lead level during pregnancy in South Central Los Angeles.

Twenty-five years of public health efforts produced a striking reduction in lead exposure; the blood lead average in the United States has decreased to less than 20% of levels measured in the 1970s. However, poor minority groups that live in large urban centers are still at high risk for elevated lead levels. In this study, our data showed that pregnant immigrants (n = 1,428) who live in South Central Los Angeles--one of the most economically depressed regions of California--have significantly higher (p < .0001) blood lead levels (geometric mean = 2.3 microg/dl [0.11 micromol/l]) than 504 pregnant nonimmigrants (geometric mean = 1.9 microg/dl [0.09 micromol/l]). The most important factors associated with lower blood lead levels in both groups were younger age; more-recent date of blood sampling (i.e., decreasing secular trend); and blood sampling in mid-autumn, instead of mid-spring (i.e., seasonal trend). Blood lead levels of immigrants were strongly dependent on time elapsed since immigration to the United States; each natural log increase in years of residence was associated with an approximately 19% decrease in blood lead levels. Although blood lead means for both groups were almost the same as the estimated national average, 25 of the 30 cases of elevated blood lead (i.e., > or = 10 microg/dl [0.48 micromol/l) occurred in the immigrant group. The odds ratio (95% confidence intervals within parentheses) for having elevated blood lead levels (a) was 9.3 (1.9, 45.8) if the immigrant engaged in pica; (b) was 3.8 (1.4, 10.5) if the immigrant had low dietary calcium intake during pregnancy; and (c) was .65 (.43, .98) for every natural log unit increase of years of residence in the United States. The control of pica and dietary calcium intake may offer a means of reducing lead exposure in immigrants.

Adolescent↗

Blood lead level and blood pressure during pregnancy in South Central Los Angeles.

In many studies in which the relationship between blood pressure and blood lead level has been examined, investigators have found significant--but small--associations. There was only one previous report of a significant association of blood lead with blood pressure in pregnant women. We measured blood lead level and sitting blood pressure of 1,627 women in their third trimester of pregnancy. We eliminated subjects with known causes of hypertension. Most women (98.4%) were normotensive. We controlled for body mass index, age, and stress--among other factors--and constructed multiple-regression models of lead association with diastolic and systolic blood pressures. Immigrants (73% of total) had significantly higher blood lead levels and different blood pressures than nonimmigrants, suggesting that analysis be stratified by "immigrant, nonimmigrant" status. Positive relationships between blood lead level and blood pressure were found only for immigrants (p < or = .001). From the 5th to 95th blood-lead percentiles (0.9-6.2 microg/dl) in immigrants, systolic blood pressure increased 2.8 mm Hg, and diastolic blood pressure increased 2.4 mm Hg. Higher prior lead exposure of immigrants (97.7% from Latin countries) than nonimmigrants might explain the differential effect of these low levels of blood lead on blood pressure in nonimmigrants. Perhaps some immigrants are at higher risk than nonimmigrants for lead-associated elevated blood pressure during pregnancy, despite blood lead levels within the currently considered acceptable range.

Adult↗

Therapeutic evaluation of ketoconazole in patients with coccidioidomycosis.

Eleven adult patients (seven men and four nonpregnant women) with coccidioidomycosis were treated orally with ketoconazole (R41,400). Two patients presented with disseminated coccidioidomycosis, six with pulmonary coccidioidomycosis, and three with the chronic cutaneous form of the disease. Diagnosis was established by culture of Coccidioides immitis and/or histopathologic identification of the fungus. All patients received 400 mg of ketoconazole per day for the first 10 days; afterwards four of them received 200 mg per day. Evaluation indicated that nine patients improved, one did not, and one could not be assessed. Treatment of coccidioidomycosis with ketoconazole appears to be reasonably effective and produces fewer adverse effects than does amphotericin B; however, further studies of the efficacy of this new drug are needed.

Adult↗

Toxic effects of capsaicin on keratinocytes and fibroblasts.

Pain management for partial-thickness burns and split-thickness skin graft donor sites remains a persistent problem. Topical capsaicin (trans-b-methyl-N-vanillyl-noneamide) has been successful for pain relief in postherpetic neuralgia, arthritis, and diabetic neuropathy. It is thought to work by inhibiting type C cutaneous factors and by releasing substance P, which is essential for wound healing. To evaluate the effects of topical capsaicin treatment on burn wounds and donor sites, an in vitro study was designed to consider cytotoxic effects of commercial concentrations of capsaicin on keratinocytes and fibroblasts. Human keratinocytes and human fibroblasts were grown in tissue culture and exposed to varying concentrations of capsaicin (0.025% weight/volume to 0.2% weight/volume). In addition, fibroblast-seeded collagen matrixes were exposed to capsaicin to evaluate the compound's ability to cause cytotoxic effects beneath the surface. Keratinocyte growth was reduced 21% to 31% in commercial concentrations of capsaicin 0.025% to 0.20% weight/volume. Fibroblasts were reduced 5% to 10% during the first 6 hours of exposure to capsaicin and 30% after 24 hours across the full range of concentrations tested. At concentrations of at least 0.1% weight/volume, capsaicin penetrated the collagen matrixes, resulting in fibroblast degeneration not only on the surface but also in the inner layers. On the basis of the fact that capsaicin was demonstrated to be cytotoxic to keratinocytes and fibroblasts and on the basis of its known detrimental effect on wound healing, it does not appear that topical capsaicin is indicated for the treatment of burns.

Animals↗

Hemolytic uremic syndrome in children: platelet aggregation and membrane glycoproteins.

PURPOSE: Several mechanisms have been proposed to explain the fibrin-platelet thrombosis at the microcirculation level in the different clinical conditions of hemolytic uremic syndrome (HUS). The relationships between platelet structure and function during the first 4 weeks of evolution of the disease were studied to understand the mechanism of platelet alteration. PATIENTS AND METHODS: Coagulation parameters, platelet counts, and aggregation were studied in 49 children, and membrane glycoproteins (GPs) in 20 of the 49 children (mean age, 17 months) with HUS (Group 2) were studied during the first 4 weeks of evolution of the disease. RESULTS: No disseminated intravascular coagulation was found in patients with recurrent or persistent thrombocytopenia. Platelet aggregation was sequentially performed during the first weeks of evolution. All patients had a functional decrease in the acute period of HUS. Platelet GPs GPIb, GPIIbIIIa, GPIIb, and GPIIIa were evaluated. GPIIbIIIa complex presented low level and never reached normal values during the first 4 weeks of disease. CONCLUSIONS: Platelet alterations are probably caused by multiple mechanisms: "exhausted" platelets, structural membrane alterations caused by arginine-glycine-aspartic peptide blockade, or diminished or nonfunctional membrane GPIb and GPIIbIIIa complexes.

Bacterial Toxins↗

Somatosensory evoked potentials in juvenile myoclonic epilepsy.

We analyzed the somatosensory evoked potentials (SEP) of 35 patients with juvenile myoclonic epilepsy (JME), 26 patients with idiopathic generalized epilepsy (IGE), and a control group consisting of 24 healthy people. The N19-P25 interval was significantly prolonged in the IGE group both as compared with the JME and control groups. This finding may be related to antiepileptic drug (AED) treatment, principally phenytoin (PHT). No differences were noted in N19 amplitude in any group. The P25 and N33 amplitudes were significantly higher in the JME group. In 5 patients of the JME group (14%) "giant SEP" were observed, but no differences were evident in the electroclinical characteristics with respect to the other JME patients. JME is one of the causes of giant-SEP.

Adolescent↗

Safety evaluation of chronic fluconazole therapy. Fluconazole Pan-American Study Group.

The possible adverse effects of chronic, high-dose fluconazole therapy are detailed from analysis of a multicenter, dose-escalating study of the therapy of invasive mycoses. Ninety-three adult patients were studied, 48 of these received > or = 6 months therapy and 20 received > or = 1 year. Fifty-eight patients received > or = 300 mg/day, and 7 received > or = 600 mg/day. One patient received 1,997 g over 86 months. Twenty-seven percent experienced possible symptomatic side effects, which resulted in 2 patients discontinuing therapy, and 42% had asymptomatic laboratory abnormalities, none of which were progressive. Headache, hair loss and anorexia were the most common symptoms experienced (each by 3% of patients), and eosinophilia and aspartate aminotransferase increases were the most common laboratory findings (12 and 10%, respectively). Fluconazole appears well tolerated and safe in these doses and durations.

Adult↗

Alpha-1,4-glucosidase activity and the presence of germinal epithelium cells in the semen for differential diagnosis of obstructive and nonobstructive azoospermia.

Among azoospermics, the activity of seminal alpha-glucosidase (alpha G) is low in obstruction (OBS) cases, but there is no agreement regarding its value in others. With the hypothesis that a more marked decrease in alpha G activity occurs in OBS than in spermatogenesis arrest (SA), the enzyme was measured in the following groups: (1) vasectomized males (n = 15), (2) azoospermics with OBS (n = 7), (3) azoospermics with SA (n = 11), and (4) fertile males (n = 15). Patients within groups 2 and 3 had a testicular volume > or = 15 mL, no clinical evidence of abnormal epididymis, normal serum gonadotropins, and histological diagnosis. alpha G activities (mU/g protein, means +/- SD) by group were (1) 131 +/- 60, (2) 312 +/- 186, (3) 728 +/- 303, and (4) 1176 +/- 374. All between-group differences were significant (t test, p < .01), except for groups 1 vs. 2 comparison (.05 > p > .01). These results support the notion that SA is associated with a decrease in alpha G that is less marked that seen in OBS. The search for germinal epithelium cells in semen also allows discrimination between these two azoospermic groups.

Clinical Enzyme Tests↗