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Biomedical subjects

F Diaz

Publications and source records attributed to F Diaz.

At least 73 records · Page 4Linked to original sources
PubMed1991

Diagnosis of cysticercosis in endemic regions. The Cysticercosis Working Group in Peru.

Taenia solium cysticercosis is a frequent cause of neurological disease in developing countries. Specific diagnosis of cysticercosis is difficult. We obtained serum and/or CSF samples from 204 consecutive patients admitted to a neurological ward in Lima, Peru, and looked for antibodies specific for T solium with the enzyme-linked immunoelectrotransfer blot (EITB) assay. 21 (12%) of 173 serum samples from these patients were EITB-positive. In contrast, only 2 (1.5%) of 135 patients attending a public endoscopy clinic and 1 (1%) of 88 patients attending a private endoscopy clinic were seropositive. 1 (1%) of 98 pregnant women living in a Lima shanty town was EITB-positive. 15 (58%) of 26 neurology patients diagnosed clinically as having cysticercosis were seronegative. Routine screening by EITB of all patients with neurological symptoms from areas of endemic cysticercosis would avoid misdiagnosis of this common and treatable disease.

Adolescent↗
PubMed1991

Propionyl-CoA condensing enzyme from Ascaris muscle mitochondria. I. Isolation and characterization of multiple forms.

The condensation of two propionyl-CoA units or a propionyl-CoA with acetyl-CoA is required for the synthesis of 2-methylvalerate or 2-methylbutyrate, respectively, two of the major fermentation products of Ascaris anaerobic muscle metabolism. An enzyme that preferentially catalyzes the condensation of propionyl-CoA rather than acetyl-CoA has been purified from the mitochondria of the parasitic intestinal nematode Ascaris lumbricoides var. suum. The purified enzyme is over 10 times more active with propionyl-CoA than with acetyl-CoA as substrate. It also catalyzes the coenzyme A-dependent hydrolysis of acetoacetyl-CoA at a rate four times higher than the propionyl-CoA condensation reaction. The purified Ascaris condensing enzyme preferentially forms the 2-methyl-branched-chain keto acids rather than the corresponding straight chain compounds. The native molecular weight of the purified enzyme was estimated to be 160,000 by gel filtration chromatography and 158,000 by high pressure liquid chromatography. The enzyme migrated as a single protein band with Mr 40,000 during sodium dodecyl sulfate-polyacrylamide electrophoresis, indicating that the enzyme is composed of four subunits of the same molecular weight. Chromatography on CM-sephadex resulted in the isolation of two separate peaks of activity, designated as A and B. Both A and B had the same molecular weight and subunit composition. However, they differed in their specific activities and isoelectric points. The pIs of condensing enzymes A and B were 7.6 and 8.4, respectively. Propionyl-CoA was the best substrate for the condensation reaction with both enzymes. However, the specific activity of enzyme B for both propionyl-CoA condensation (3.4 mumol/min/mg protein) and acetoacetyl-CoA thiolysis (13.8 mumol/min/mg protein) was 2.4 times higher than that obtained with enzyme A. Similarly, chromatography on phosphocellulose resolved the Ascaris condensing enzyme activity into one minor and two major peaks. All of these components had the same molecular weight and subunit composition, but differed in their specific activities. The two major phosphocellulose peaks cross-reacted immunologically when examined by the Ouchterlony double immunodiffusion technique. In addition, antiserum against the phosphocellulose most active form cross-reacted with forms A and B isolated by chromatography of the enzyme on CM-Sephadex, indicating that all forms were immunochemically related.

Alcohol Oxidoreductases↗
PubMed1991

A cyclic AMP-activated K+ channel in Drosophila larval muscle is persistently activated in dunce.

Single-channel recording from longitudinal ventrolateral Drosophila larval muscle reveals the presence of a potassium-selective channel that is directly and reversibly activated by cAMP in a dose-dependent fashion. Activation is specific and it cannot be mimicked by a series of agents that include AMP, cGMP, ATP, inositol trisphosphate, and Ca2+. Channel current records obtained from larval muscle in different dunce mutants possessing abnormally high levels of cAMP show that, in the mutants, the channel displays an increased probability of opening.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1991

Evaluation of brain SPECT in the diagnosis and prognosis of the normal pressure hydrocephalus syndrome.

From January 1989 to September 1990 fourteen patients with the Normal Pressure Hydrocephalus (NPH) syndrome were diagnosed in our Service. All patients were studied by CT-Scan, Radionuclide Cisternography and brain Single Photon Emission Computed Tomography (SPECT). In this series, the predictive value of the brain SPECT was assessed. A statistically significant relationship between SPECT patterns and clinical outcome was found. The patients who showed a Dementia Alzheimer Type (DAT) pattern on SPECT had worse results. The results are discussed and compared with those reported by other authors.

Aged↗
PubMed1991

Spontaneous dissecting aneurysm of the common iliac artery.

A 52-year-old man sought medical advice for sudden onset of intermittent claudication of the left lower limb after 50 meters walking. Aortography documented a dissecting aneurysm limited to the left common iliac artery. After resection, a prosthetic graft was inserted. Pathology showed that the cause of the dissection was atheroma. Spontaneous dissecting aneurysm of the common iliac artery is rare. Rupture represents the principal hazard. A high index of suspicion should lead to diagnosis as soon as signs of lower limb ischemia, occasionally transient, appear.

Aortic Dissection↗
PubMed1991

Psychological aspects of insulin-induced thirst.

Fifteen normal volunteers received one insulin injection or saline in two nonconsecutive days. At 0', 30', 60' and 90' water intake was measured. Simultaneously subjective thirst and hunger were recorded by running a set of psychological tests. Water intake was higher after insulin than saline at 60' and 90'. Insulin increases thirst sensation even before the sensation of hunger.

Adult↗
PubMed1991

Histochemical study of RNA content of neurones in the dorsal lateral geniculate nucleus during postnatal development.

Nuclear and cytoplasmic dLGN neurons were investigated by cytophotometric measurements of RNA. This study has been carried out in rats from birth to adulthood. In order to quantify the RNA content a cytophotometer was used. Extinction mean values were obtained which indicated RNA concentrations per surface unit. The nuclear and cytoplasmic surface were calculated simultaneously and from the product of the mean extinction and the surface the RNA total content was calculated. Our results have suggested that the changes are age-related. From day 1 to day 21 the neuronal size and RNA content increase; this may somehow be involved with the differentiation process. Around post-natal day 21 neuronal maturation may begin, reaching its optimal phase around day 42, on which the RNA concentration per surface unit, surface neuronal content and RNA total content are stable.

Analysis of Variance↗
PubMed1991

The effects of sleep posture and sleep stage on apnea frequency.

The Apnea Plus Hypopnea Index (A + HI) of 60 male positional sleep apneics was analyzed by sleep stage to determine if positional differences are limited to NREM sleep. Differences in apnea severity by sleep position were found to persist in REM sleep and to be of equal extent to those differences found in NREM sleep, despite the fact that there is also a significant increase in the frequency of apneic events associated with REM sleep. The positional effect persists in REM sleep, making treatments to control sleep posture a viable option.

Adult↗
PubMed1991

A comparative study of treatments for positional sleep apnea.

Sixty male patients all with apnea plus hypopnea indices (A + HI) above 12.5, who met a criterion of positionality by having two or more times the rate of these events during supine sleep in comparison to their lateral sleep rate, were randomly assigned to one of four treatments for 8 weeks. All were restudied for two nights, one with and one without treatment devices. On treatment more than half the patients in each group reduced their A + HI to within normal limits and a third remained WNL without the use of devices. Half of those trained to sleep in the lateral position with the help of an alarm maintained this learning without the alarm as did half of those who were encouraged to learn this sleep posture on their own. There is an additive effect for the positional patient from wearing a tongue retaining device (TRD) if they continue to sleep in the supine position. Factors associated with successful treatment include overall severity, severity in the lateral position, weight, weight change, nasal patency and motivation to help their condition.

Behavior Therapy↗
PubMed1991

Effect of cigarette smoking on the humoral immune response in pigeon fanciers.

Tobacco smoking is associated with increased prevalence of various diseases. In this study, we have used an indirect enzyme-linked immunosorbent assay (ELISA) to investigate the specific IgG response to pigeon serum and its relationship to tobacco smoking. In a large group of pigeon fanciers the development of pigeon breeder's disease and some of the clinical features were also investigated. We found a sensitization rate of 31.9%, a lower degree than that found by other authors, in spite of using a less specific antigen. We also found that fanciers who are current cigarette smokers had significantly lower levels of IgG antibody to pigeon serum (P less than 0.001). Finally, 11.9% of the population had chronic bronchitis as their only manifestation of possible pigeon-related disease. 19.6% of the sensitized fanciers had chronic bronchitis, were non-smokers and had no other risk factor for developing chronic bronchitis.

Adolescent↗
PubMed1990

Prevalence and etiology of respiratory distress in infants of diabetic mothers: predictive value of fetal lung maturation tests.

The purpose of this study was to investigate the prevalence of respiratory distress syndrome attributable to surfactant deficiency in infants of diabetic mothers tested for fetal lung maturation. Three tests were assessed: (1) lecithin/sphingomyelin ratio, (2) phosphatidylglycerol concentration, and (3) optical density at 650 nm. From January 1987 through June 1989, 526 diabetic gestations were delivered within 5 days of fetal lung maturation testing. Surfactant-deficient respiratory distress syndrome was present in five infants (0.95%); all were less than 34 weeks' gestational age. Other causes of respiratory distress were transient tachypnea of the newborn (n = 5), hypertrophic cardiomyopathy (n = 4), pneumonia (n = 2), polycythemia (n = 1), and meconium aspiration syndrome (n = 1). The use of standard maturity values of lecithin/sphingomyelin ratio greater than or equal to 2.0, phosphatidylglycerol greater than 2% to 5%, and optical density at 650 nm greater than or equal to 0.150 were evaluated. Each test had a 100% sensitivity in identifying surfactant-deficient respiratory distress syndrome and a 100% negative predictive value in identifying the absence of disease. All three tests had a low positive predictive value: 15% for lecithin/sphingomyelin ratio, 9% for phosphatidylglycerol, and 3% for optical density at 650 nm. We concluded that most cases of respiratory distress in the infants of diabetic mothers were unrelated to surfactant deficiency. The standard maturity values used in fetal lung maturation tests were valid in the diabetic gestation. The optical density at 650 nm was useful as a first-line test to predict the absence of surfactant-deficient respiratory distress syndrome.

Cardiomegaly↗
PubMed1990

Insulin stimulation of water intake in humans.

Drinking response to the intravenous administration of insulin (0.1 U/kg) was studied in 15 volunteers (eight males and seven females). Water intake was significantly higher after insulin than after saline administration during the 90-min period studied. Plasma glucose decreased significantly in individuals receiving insulin and the time of the maximum decrease (30 min) was concurrent with the beginning of water intake. Haematocrit values in the insulin-treated group were also significantly higher at that time. Plasma renin activity (PRA) after insulin administration was higher than under basal conditions or after saline injection. On the other hand, psychological responses indicated that insulin probably elicits thirst prior to the hunger which appears with hypoglycaemia. A possible role of endogenous insulin in meal-related thirst is hypothesized.

Adult↗
PubMed1990

MRI and diabetic foot infections.

The role of magnetic resonance imaging and plain radiographs in evaluating osteomyelitis in the diabetic foot was studied. Fifty patients were prospectively examined by magnetic resonance imaging and plain radiographs to determine the extent of infection. Thirty-seven patients had positive MRI for osteomyelitis and 19 were positive with conventional radiography. Thirteen patients had negative MRI healed with short course of antibiotics. Five patients with positive MRI received four weeks' course of intravenous antibiotics with two still having persistent infection in the six weeks follow-up. Thirty-two patients underwent surgery with favorable results. Sixty-two bone specimens were obtained for histologic evaluation of osteomyelitis. In cases with histologic proof of diagnosis, magnetic resonance sensitivity was 99%, specificity was 81%, and accuracy was 94%. Thus magnetic resonance imaging was shown to have a high sensitivity, specificity, and accuracy in detecting osteomyelitis.

Adult↗
PubMed1990

Metals and the liver in Alzheimer's disease. An investigation of hepatic zinc, copper, cadmium, and metallothionein.

Significant alterations of tissue metal levels have been reported in Alzheimer's disease (AD). Because the liver is intimately involved in metabolism and storage of metals, it may provide a useful site for study of these metals in AD. This study compares livers in AD and controls in their concentrations of zinc, copper, cadmium, and metallothionein, a metal-binding protein important in regulation of metal metabolism. Liver tissue was obtained from 17 patients with AD and 17 age- and sex-matched controls within 12 hours of death and stored at -70 degrees C. Neuropathologic confirmation of diagnosis was available in all cases. Liver homogenates (20%) were used for metal analysis by atomic absorption spectroscopy after wet digestion. Cytosolic metallothionein levels were quantitated by the cadmium or silver saturation method. A significant decline in body and liver weight was found in patients with AD, with no significant change in liver protein or DNA concentration. Total hepatic cadmium (P less than .001) and zinc (P less than .030) concentrations were significantly elevated in AD. The Sephadex G75 chromatographic profile was altered in AD with reduction in zinc bound to metallothionein fractions and increased binding to high molecular weight fractions. These data suggest that the metabolism of cadmium and zinc is altered in AD.

Aged↗
PubMed1990

Islet transplantation restores normal serum amylase levels in diabetic rats.

Diabetes is associated with a diminution in exocrine pancreatic function. The goal of our study was to investigate whether the altered exocrine pancreatic function of streptozotocin-induced diabetic rats could be ameliorated by islet transplantation. Diabetic rats received either more than 1,000 syngeneic islets intraportally (islet transplantation group) or pancreatic, nonviable insular tissue (sham transplantation group). Plasma amylase and insulin levels in diabetic rats were significantly lower than in normal rats. The exocrine pancreas of streptozotocin-induced diabetic rats showed alterations (decrease of zymogen granules, diminution of endoplasmic reticulum, clusters of ribosomes without organization) in the structure of acinar cells at the electron microscopic level. After islet transplantation, plasma glucose levels were restored to normal values, and those of amylase and insulin gradually increased to normal values. A positive correlation between plasma levels of amylase and insulin was found. Three months after islet transplantation, the islet-transplanted rats did not show morphologic alterations of the acinar cells which were still found in the sham-transplanted rats. It is concluded that alterations of exocrine pancreas in streptozotocin-induced diabetic rats are ameliorated by islet transplantation.

Amylases↗
PubMed1990

[Occult tumors of the parotid gland and facial paralysis. A diagnostic problem].

The facial palsy produced by a parotid tumour, could be misdiagnosed due to the absence of a palpable mass or other any signs in the computerized axial tomography or nuclear magnetic resonance. However there are data derived from the facial anatomy, course and clinical characteristics from the palsy that could make us thinking on the presence of a parotid tumour. The objective of this article is to present this characteristics, together with a serial of clinic cases which coursed in the beginning with a facial palsy and had problems in their diagnostic. It's also remarked the significance of the presence or not of perineural infiltration to the parotid tumours that will condition not only the prognosis but also the clinic course.

Aged↗
PubMed1989

Effects of inhibitors of the renin-angiotensin system on water intake after insulin administration.

Male wistar rats drank in a dose-related manner, in response to 1 to 40 U/kg of i.p. insulin. Maximum intakes took place during the first 30 min after i.p. insulin administration, coinciding with the period of maximal drop of blood glucose. Plasma renin activity (PRA) in rats treated with i.p. insulin was higher than in basal conditions or after saline injection. Nephrectomy and adrenalectomy did not abolish insulin-induced drinking. A low dose of captopril (0.1 mg/kg s.c.) did not modify insulin-induced drinking, but a higher dose (10 mg/kg s.c.), or enalapril (0.5 mg/microgram s.c.), significantly increased insulin-induced drinking. Enhancement of insulin-induced drinking by s.c. captopril was not secondary to an increased diuresis. Captopril (50 micrograms i.c.v.) significantly reduced the cumulative water intake after i.p. insulin (20 U/kg i.p.) plus s.c. captopril (10 mg/kg). The blockade of central receptors for angiotensin II with sarile-AII (5 micrograms) significantly diminished insulin-induced drinking. It appears that the peripheral renin angiotensin system is not necessary for insulin-induced drinking but central angiotensin II plays an important role.

1-Sarcosine-8-Isoleucine Angiotensin II↗