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Biomedical subjects

M Diaz

Publications and source records attributed to M Diaz.

At least 109 records · Page 6Linked to original sources
PubMed1989

Hemolytic uremic syndrome and diarrhea in Argentine children: the role of Shiga-like toxins.

Shiga-like toxin-producing Escherichia coli have been associated with hemorrhagic colitis and the hemolytic uremic syndrome (HUS). Because Argentina has the highest reported frequency of HUS in the world, Argentine children were prospectively studied during the HUS seasons for evidence of Shiga-like toxin-related diseases. On the basis of serology, fecal cytotoxin neutralization, stool cultures, and DNA hybridization of colony lysates, most children with HUS had evidence of infection with Shiga-like toxin-producing organisms. Children with spring-summer diarrhea also commonly (32%, confidence interval 18%-46%) had clear-cut evidence of such infection. No controls (children without gastrointestinal, renal, or hemolytic disease) had free fecal cytotoxin, positive cultures for E. coli O157:H7, or DNA probe-positive organisms; 20% of them had low serum titers of antibodies to Shiga-like toxins. E. coli O157:H7 was not common in either HUS or diarrhea patients. The high frequency of Shiga-like toxin-induced diarrhea in young children in Argentina probably explains the high incidence of HUS in this country and suggests that HUS is a relatively uncommon complication of Shiga-like toxin-related disease.

Argentina↗
PubMed1988

Prenatal lidocaine and the auditory evoked responses in term infants.

We examined the effects of maternal lidocaine hydrochloride anesthesia on the brain-stem auditory evoked responses (BAERs) in neonates born by cesarean delivery. Sixteen term neonates were enrolled in the study. Eight neonates were delivered by cesarean section following lidocaine anesthesia, and eight were delivered by spontaneous vaginal delivery without maternal anesthesia. A BAER was obtained on all of the neonates on the first day of life. A significant delay was noted in the central neural component of the BAER at 90 dB. The wave I through V interpeak latency for both ears was noted to be 5.3 ms for the neonates exposed to lidocaine and 4.9 ms for the controls.

Anesthesia, Epidural↗
PubMed1988

The role of aldosterone in water and electrolyte transport across the colonic epithelium of the lizard, Gallotia galloti.

1. The effects of D-aldosterone on the electrical properties and ionic transport have been analysed (in vitro) in the colonic epithelium of the lizard, Gallotia galloti. 2. The injection of 30 g of D-aldosterone induced a significant rise of plasma aldosterone concentration, sustained for 4 hr after administration. 3. Intraperitoneal injections of D-aldosterone caused a slight reduction of transmural potential difference (PD) and short-circuit current (Isc). 4. Net absorption of Na+ across the colon from aldosterone-treated lizards did not increase when compared to colon from normal lizards. Cl- absorption was increased in treated lizards. 5. Addition of mucosal barium to treated tissues brought about a sustained increase of PD and Isc. 6. The absorption of fluid in normal lizards was reversed to fluid secretion in treated lizards. 7. The effects of D-aldosterone on lizard colon are compared with those reported for the colon of mammals and birds.

Aldosterone↗
PubMed1987

Cytogenetic evaluation of 163 azoospermics.

A constitutional chromosomal aberration was diagnosed in 38/163 (23.3%) azoospermic patients. Whereas the 47,XXY complement was the commonest (31/38 cases), the following abnormal karyotypes were also found: 46,XX; 46,X,del(Y) (q11); 46,X,r(Y); 46,XY,inv(1) (p3500q21.3)mat; and 46,Y,t(X;3) (q26;q13.2)mat (both the deleted and the annular Y were observed twice). Pooled data from the literature showed that the frequency of chromosomal abnormalities is higher in azoospermic (150.4/1000) than in infertile (55.3/1000) males, which in turn is higher than in newborns (less than 6/1000). The observed different frequency between azoospermic and infertile individuals is given by several types of chromosomal abnormalities, mainly by the complement 47,XXY. The analysis also showed that the male infertility secondary to rob translocations and supernumerary marker chromosomes is usually not related to azoospermia. The contrary occurs in certain rcp and gonosome;autosome translocations and in autosome inversions.

Adult↗
PubMed1986

Single-dose pharmacokinetics of oral ciprofloxacin in patients with cystic fibrosis.

The single-dose pharmacokinetics of oral ciprofloxacin were studied in ten patients with cystic fibrosis aged 18 to 34 years. Each patient received three different drug doses (500 mg, 750 mg, and 1,000 mg) at successive one-week intervals. Dosing and drug assays were double blinded. Blood and urine were assayed over the 48 hours following each dose. Ciprofloxacin was absorbed from the gastrointestinal tract. Peak serum concentrations averaged 2.8, 4.5, and 4.6 micrograms/mL respectively at the three doses, well above the mean inhibitory concentrations of most isolates of Pseudomonas aeruginosa. Time to peak concentration was approximately two hours. The range of sputum levels in three patients was 1.1-2.1 micrograms/mL at four hours after the three doses. The serum elimination half-life was 3.7 hours and was independent of dose. Urinary recovery was 26%; greater than 90% of urinary excretion occurred within the first 12 hours. The results of this study indicate that ciprofloxacin has potential for use in the treatment of P aeruginosa infections in patients with cystic fibrosis.

Administration, Oral↗
PubMed1986

Ventilatory responses to carbon dioxide in infants at risk for sudden infant death syndrome.

We examined the ventilatory response to inhaled CO2 in 77 infants at postconceptional ages ranging from 31 to 50 wk, 43 of whom were also evaluated with a 12-h pneumocardiogram (PCG). Infants were tested after sedation with chloral hydrate, and monitored with ECG and transcutaneous oxygen and CO2 monitors. Sleep state was evaluated by visual inspection of the infant's behavior. Among the 43 infants examined with the PCG, 22 had abnormal PCGs. Of these, 27% had significantly (p less than .05) abnormal CO2 response slopes, compared to 9% of those with normal PCGs. Breathing frequency did not change after CO2 inhalation in 82% of the abnormal PCG and in 33% of the normal PCG groups.

Apnea↗
PubMed1985

In vitro study of Fc-receptor function in autoimmune diseases.

A simple test for studying in vitro Fc-receptor function of mononuclear phagocytes is described. Immune phagocytosis is analyzed as a dynamic phenomenon by using nearly pure suspensions of monocytes incubated for diverse times with autologous erythrocytes sensitized with highly purified IgG. In a series of normal volunteers and patients with vasculitis a strict correlation has been found between this in vitro assay and the measure of splenic clearance of IgG-coated red blood cells (RBC), the classical approach for studying in vivo macrophage Fc-receptor function by using sodium chromate 51Cr as tag. The use of this in vitro assay appears to be valuable mainly in cases requiring repeated measurements of Fc-receptor function for monitoring the course of disease or the effects of therapy.

Autoimmune Diseases↗
PubMed1985

Isolation and analysis of the 21q+ chromosome in the acute myelogenous leukemia 8;21 translocation: evidence that c-mos is not translocated.

Acute myelogenous leukemia (AML), subgroup M2, is associated with a nonrandom chromosomal translocation, t(8;21)(q22,q22). The oncogene c-mos also has been localized to the q22 band on chromosome 8. There is also evidence that genes on chromosome 21 may be important in the development of leukemia. To determine whether the c-mos oncogene has been translocated in AML-M2 with this translocation and to isolate DNA sequences and genes from these two chromosomes that may be important in malignancy, we constructed somatic cell hybrids between a Chinese hamster ovary cell (CHO) mutant defective in glycine metabolism and myeloblasts with an 8;21 translocation from a patient with AML. We isolated the 21q+ chromosome of this translocation in a somatic cell hybrid and showed that the c-mos oncogene had not been translocated to chromosome 21, ruling out the possibility that translocation of c-mos to chromosome 21 is necessary for development of AML-M2. In addition, there was no detectable rearrangement of the c-mos locus within a 12.4-kilobase region surrounding the gene, indicating that rearrangement of the coding region of the gene itself or alteration of proximal 5' or 3' flanking sequences is not involved. We used this hybrid to determine whether specific DNA sequences and biochemical markers from chromosomes 8 and 21 had been translocated in this case.

Animals↗
PubMed1982

Bedside blood glucose determinations in critical care medicine: a comparative analysis of two techniques.

The accuracy of a new reagent test strip (Chemstrip BG) for the quantitative estimation of whole blood glucose concentration was compared to that of a widely used test strip (Dextrostix). To perform the comparative study, venous blood specimens were obtained from 133 patients. Interpretations of reagent strip glucose readings were made by three observers who separately recorded their impressions from the two strips on each patient. These estimated levels were compared to quantitative (glucose oxidase) concentrations measured from the same specimen. Although there were significant correlations (p less than 0.001) between both reagent strips and the measured values, the Chemstrip BG results more closely approximately measured values for the range of glucose concentrations encountered (10-600 mg/dl). In addition, Chemstrip BG was easier to read and measured a wider range of values than Dextrostix and, unlike Dextrostix, Chemstrip BG strips could be stored for review at a later time. This new glucose test strip accurately and rapidly determines whole blood glucose concentration at the bedside.

Blood Glucose↗
PubMed1982

Sorbitol dehydrogenase (EC.1.1.1.14) polymorphism in human seminal plasma.

Sorbitol dehydrogenase was electrophoretically determined in 173 different samples of human seminal plasma in cellulose acetate as support media. This method permitted the identification of three phenotypes : one with a slow band, one with a fast band and the third with both slow and fast bands. These findings can be explained either by the presence of two alleles at a different SORD locus determining the enzyme in seminal plasma or by the formation of secondary isozymes.

Electrophoresis, Cellulose Acetate↗
PubMed1981

Temporal lobe epilepsy -- not a consequence of childhood febrile convulsions in Denmark.

Temporal lobe epilepsy in particular has been considered a consequence of childhood febrile convulsions. Previous studies have dealt with populations of epileptic children. This retrospective, follow-up study concerns 362 children with a primary diagnosis of febrile convulsions. 4% developed epilepsy. When followed into early adulthood one half of those remitted. The incidence of temporal lobe epilepsy among the none-remitters did not differ from that of a random population of epileptics.

Adolescent↗
PubMed1981

ADH-dependent nephron heterogeneity in rats with hereditary hypothalamic diabetes insipidus.

Single nephron glomerular filtration rates (SNGFR) were measured by the [14C]sodium ferrocyanide infusion technique in superficial (S) and juxtamedullary nephrons (JM) of anesthetized Brattleboro rats with or without diabetes insipidus (DI and HZ, respectively). Glomerular volumes (GV) and proximal tubular lengths (PTL) were measured in the same nephrons after microdissection. Glomerular volumes were also assessed in Wistar, HZ, and DI rats in Microfil-injected kidneys. The well-known nephron heterogeneity of the mammalian kidney was absent or greatly reduced in DI compared to HZ rats. S/JM ratios for SNGFR, GV, and PTL averaged 0.71, 0.50, and 0.73 in HZ and 1.04, 0.77, and 0.90 in DI rats. This reduced nephron heterogeneity was due only to reduced dimensions and filtration rates in JM nephrons. The chronic administration of antidiuretic hormone (dDAVP or vasopressin tannate), begun at 2 wk of age and maintained until adulthood (8-10 wk), significantly decreased the S/JM ratios, i.e., restored a nearly normal nephron heterogeneity in DI rats. These results suggest that nephron heterogeneity in the rat kidney is dependent on the presence of antidiuretic hormone, and, more specifically, that ADH and/or its functional consequences can selectively induce an increase in size and filtration rate in deep nephrons.

Animals↗
PubMed1979

[Percutaneous cholangiography with the Chiba method (author's transl)].

In 92 patients with cholestasis a percutaneous cholangiography was performed. The bile duct could be visualized in 75 cases (81.5 percent). When the bile ducts were dilatated, the investigation succeeded in 94 percent, whereas in patients with normal bile ducts the rate was 65 percent. Complications occurred only in 2 cases. In one patient surgery was necessary due to biliary peritonitis. In another patient a discrete hemobilia without clinical symptoms could be found during laparotomy.

Adult↗
PubMed1978

Disorganization of myelinogenesis in tissue culture by anti-CNS antiserum.

The presence of decomplemented anti-CNS antiserum profoundly affects myelinogenesis in cultured mouse embryo spinal cord. Light and electron microscope study has shown that oligodendroglia differentiate and produce an abundance of cell processes which surround the oligodendrocytes in a chaotic, disorganized array. Where the cell processes chance to meet, they form a kind of aberrant swollen myelin. Rarely, the oligodendroglial processes ensheath axons. For the most part, the available axons remain unmyelinated. On removal of the decomplemented antiserum, oligodendroglia differentiate and form normal myelin around the available axons. Myelination of peripheral nervous system (dorsal root ganglion) axons in the same preparations is unaffected by the presence of the antiserum. Thus, under these circumstances, the message from the neuron to the oligodendrocyte to make myelin is apparently intact, yet there is interference with the ability of the oligodendroglial cell process to find, attach to and encircle CNS axons with a normal myelin sheath.

Animals↗
PubMed1978

Antiserum-induced dissociation of myelinogenesis in vitro. An ultrastructural study.

Mature, myelinated cultures of mouse spinal cord tissue exposed to heated (decomplemented) sera from animals suffering from experimental allergic encephalomyelitis demonstrate a unique pattern of myelin swelling without demyelination. In the present study, three concentrations of heated experimental allergic encephalomyelitis sera (5, 15, and 25 per cent) were applied to spinal cord cultures from the time of explantation and continued for 33 days therafter. The sera were obtained from rabbits with the exposed cultures, glial cell differentiation occurred at timepoints comparable to those in normal unexposed sister cultures. Oligodendroglia produced a profusion of cytoplasmic processes which compacted to form aberrant myelin with a periodicity double that of normal myelin, containing four leaflets in the position of the normally bilamellar intraperiod line. The degree of the oligodendroglial abnormality was dose dependent, 25 per cent heated experimental allergic encephalomyelitis serum being the most potent. Frequently, in older cultures, large diameter axons, which under normal circumstances would have been well myelinated, were devoid of myelin sheaths although abundant aberrant myelin could be seen around nearby oligodendroglial cells. Rarely similar aberrant myelin was deposited around axons. It appeared, therefore, that the oligodendroglial cells had proliferated myelin which was unable to reach axons, possibly reflecting a failure in recognition between the two.

Animals↗
PubMed1977

Vertical transmission of the virus of hepatitis B and neonatal hepatic cirrhosis in an Argentine family.

In a family in which the mother was a healthy HBsAg and anti HBc carrier, and the father had a chronic persistent hepatitis with anti HBs and anti HBc positive, the development of neonatal cirrhosis in two of the children was proved to be present. One of the girls was an anti HBs carrier (anti HBc was not determined) and the other had positive anti HBs and anti HBc. Both died and the diagnosis of cirrhosis was confirmed. The two healthy daughters were anti HBc carriers.

Antibodies, Viral↗
PubMed1975

Growth in experimental renal failure: role of calorie and amino acid intake.

In order to evaluate the role of calorie and protein intake in growth impairment due to chronic renal failure (CRF), a subtotal nephrectomy was performed in weanling Wistar rats. A two-thirds reduction of renal function was obtained, which induced a marked growth retardation. Growth retardation was identical in nephrectomized and in pair-fed controls, and thus appeared to be entirely due to a deficient food intake. Using low protein diets, administration of a supplement with small amounts of essential amino acids (EAA) resulted in accelerated growth associated with a higher calorie intake, a better utilization of ingested calories for growth and a greater fall of blood urea nitrogen concentration.

Amino Acids, Essential↗