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Biomedical subjects

R Aguirre

Publications and source records attributed to R Aguirre.

At least 19 recordsLinked to original sources
PubMed1996

Changes in renal function in primary hypothyroidism.

Renal function impairment and electrolyte disorders in hypothyroidism are frequently subtle and rarely observed in clinical practice. To assess the extent of these defects, serum concentration of electrolytes and glomerular filtration rate were estimated before and after thyroid replacement therapy in 41 patients with primary hypothyroidism. All patients had decreased glomerular filtration rates and 22 patients had increased serum creatinine levels. Although a relationship between creatinine clearance and serum thyrothropin-stimulating hormone was not found, a weak correlation between age and serum creatinine concentration was observed. Hyponatremia was documented in 45% of 22 patients with elevated serum creatinine but in only 21% of 19 patients with normal creatinine. All these defects were corrected by treatment with thyroid hormone. We conclude that creatinine clearance was slightly decreased in all patients with hypothyroidism, this decrease being more noticeable in elderly patients. The greater the impairment in renal function, the more common was the occurrence of hyponatremia.

Creatinine↗
PubMed1995

Fluconazole treatment of candida peritonitis with delayed removal of the peritoneal dialysis catheter.

Candida peritonitis was treated with fluconazole in ten continuous ambulatory peritoneal dialysis (CAPD) patients without immediate removal of the peritoneal catheter. Shortly prior to diagnosis, six patients (60%) had received broad-spectrum antibiotics. Gram stain of peritoneal fluid detected yeast in 70% of cases. In eight patients the peritoneal dialysis catheter was removed within one week of diagnosis because of clinical deterioration. In the majority of cases (90%), candida peritonitis resolved only after catheter removal in spite of ongoing fluconazole therapy. Fluconazole was well tolerated by all patients.

Antifungal Agents↗
PubMed1995

[Paternity study applying DNA polymorphism: evaluation of methods traditionally used in Chile].

Simultaneous detection of several VNTR loci using a single DNA probe is the basis of the technique called "DNA fingerprint" (DNAfp) of increasing application in parenthood identification. According to the data gathered by different laboratories worldwide, father exclusion can be made in a larger number of cases when compared with the customary tests based on erythrocyte antigens. The question could then be whether DNAfp will completely replace erythrocyte antigens tests. We report here our experience in applying DNAfp to 92 samples corresponding to 34 paternity cases and comparing these with the results obtained with the antigens of the systems ABO, Rh, MNSs, Duffy and Kidd. Most of the HaeIII/digested DNA samples produced 13 to 16 bands larger than 4.3 Kb (average 14,0761 +/- 2,205). Average band sharing between pairs of unrelated individual was 1,9107 +/- 1,083. Two cases presenting an a posteriori probability of being the father of 80.7% and 76.5% by erythrocyte antigens were clearly excluded by DNAfp. All exclusions made by antigens were confirmed by DNAfp. In the cases reported as father "rather probable" (28 cases) by DNAfp, these shared with the child 6,7407 +/- 1.7 bands on average. Because of time, cost and simplicity we favor a procedure starting with the antigens test and continuing with DNAfp only when an exclusion is not possible. Economy will increase as the number of exclusions increases.

Blood Grouping and Crossmatching↗
PubMed1994

High flow peritoneal dialysis.

We have developed a catheter extension/continuous ambulatory peritoneal dialysis (CAPD) set (ANDY high flow set) of larger lumen (minimum internal diameter 3.25 mm), and compared peritoneal dialysate flow rates in two groups of 6 stable CAPD patients of comparable age, sex distribution, and time on dialysis according to type of catheter. Both groups were studied with two different extension/sets, standard ANDY and ANDY high flow set. The shortest infusion time was observed with the combination Cruz catheter/ANDY high flow set. The switch to a high flow set decreased significantly the inflow time of both types of catheter, and the infusion time of the Tenckhoff catheter/ANDY high flow combination approximated that of the Cruz/ANDY combination. Likewise, the dialysate outflow rates were highest with the Cruz catheter/ANDY high flow set than with any other catheter/set combination (p = 0.005). This was apparent, not only in the total outflow time, but also in the vol/min during the first 4 min (p = 0.005). None of the patients experienced discomfort during the dialysis exchanges with the high flow system. This combination of Cruz catheter/high flow set effectively reduces the dialysis exchange time and is very much appreciated by the patients.

Catheters, Indwelling↗
PubMed1993

Calcium mass transfer in CAPD: the role of convective transport.

One hundred and fifty calcium (Ca) balance studies were performed in 50 patients treated with CAPD using dialysate with a 1.75 mmol/l (7 mg/dl) Ca content, in order to calculate the peritoneal balance of Ca by measuring the Ca in all the effluent for a 24-h period, and looking at the influence of serum ionized Ca and the ultrafiltration rate in the calcium balance. Of the 150 balance studies, 77 were made using four exchanges of dialysate per day and 73 using three exchanges per day. The serum ionized Ca was 1.17 +/- 0.09 mmol/l, the ultrafiltration 844 +/- 723 ml/day and the peritoneal Ca transfer 39 +/- 46 m/day. The net Ca abortion with four exchanges was less than that with three exchanges per day. There was a strong negative correlation between the peritoneal Ca absorption and the ultrafiltration (r = -0.7, P < 0.00001) and with the ionized Ca (r = -0.49, P < 0.0001). Thirty-three peritoneal balance studies showed a negative Ca balance and in all 33 cases ultrafiltration was greater than 350 ml/day. We conclude that the peritoneal balance of Ca depends not only on the serum ionized Ca, but also on ultrafiltration. The lesser Ca gain observed with four dialysis exchanges per day is due to greater ultrafiltration rates present in this setting.

Calcium↗
PubMed1992

Albendazole therapy for giant subarachnoid cysticerci.

Albendazole is considered to be the drug of choice for treatment of parenchymal brain cysticercosis. Its efficacy, however, for treatment of subarachnoid cysticerci has not been established, to our knowledge. In this study, we treated four patients who had giant subarachnoid cysticerci with albendazole at daily doses of 15 mg/kg of body weight for 8 days. Computed tomographic studies showed that all cysts disappeared 3 months after the end of treatment. This was associated with marked clinical improvement in every case. Our results indicated that albendazole is highly effective for treatment of this form of the disease.

Adult↗
PubMed1992

Epilepsy due to neurocysticercosis: analysis of 203 patients.

We reviewed clinical, EEG, and CT findings of 203 patients with epilepsy due to neurocysticercosis. Seizures were generalized in 121 patients and partial in 82. Thirty-two patients had focal signs and eight had papilledema. Eighty-one had generalized and 16 had focal EEG abnormalities. CT showed parenchymal brain calcifications in 53 patients and cysts in 150. There was an increased rate of focal signs in patients with single cysts as compared with patients with multiple cysts, and focal EEG abnormalities were present only in patients with single cysts. Fifty patients were lost to follow-up. The remaining 153 patients were followed for 28 +/- 6 months; of these, 31 had calcifications and 122 had cysts. Anticonvulsants were started after the first visit in every patient. The 31 patients with calcifications remained free of seizures. Ninety-five of the 122 patients with cysts were also treated with anticysticercal drugs; of these, 79 (83%) had control of seizures. In contrast, only seven (26%) of 27 patients who did not receive anticysticercal drugs had control of seizures, indicating a strong correlation between the use of anticysticercal drugs and seizure control. Finally, of the 21 patients in whom anticonvulsants were withdrawn, 16 had relapses.

Adult↗
PubMed1992

[Paternity study in Chilean families using DNA fingerprints and erythrocyte blood markers].

In the last decade, the electromorphic phenotype corresponding to extremely polymorphic zones of DNA, that include variable number of tandem repeat loci (VNTR) of oligonucleotide sequences, have been added to classical markers to elucidate the problems of parenthood identification and ascription in human beings. Using VNTR of several loci, a band profile practically unique for each individual is obtained (DNA-fingerprints). Since the pattern of VNTR electrophoretic bands is inherited from parents in a proportion of 50% from each one, this system is extremely useful for paternity ascription or exclusion. Nine nuclear families were studied, randomly selected from a group of 170 families that were analyzed using 5 erythrocyte genetic markers and with VNTRs detected using the multi locus probe (CAC)5, aiming to explore the concordance of both methods. Results were similar for both methods; however for VNTR, there is no information available on population frequency of polymorphisms.

Blood Group Antigens↗
PubMed1991

Bilateral internuclear ophthalmoplegia after smoking "crack" cocaine.

A previously healthy 35-year-old man developed sudden diplopia after smoking "crack" cocaine. Neuroophthalmologic examination revealed findings consistent with a tegmental mesencephalic lesion which correlated closely with the computed tomographic documentation of a small midbrain hemorrhage. Cocaine abuse is a recognized cause of intracranial hemorrhage. In most patients, however, the bleeding is localized in the subarachnoid space or the subcortical white matter. To our knowledge, this is the first case of isolated midbrain hemorrhage secondary to cocaine abuse.

Adult↗
PubMed1990

[Gastric cancer in the province of Valdivia (Chile) 1977-1987].

The pathologic records of Hospital Kennedy in Valdivia include 391 cases of gastric cancer between 1977 and 1987, with a yearly incidence of 35 cases. Mean age was 58 years; 97% of males and 93% of females were 40 years or older. Surgery had been undertaken in 70%, with resection performed in 63%. Advanced lesions were found in 83% of cases, with a mean size of 35 cm (vs 15 for early lesions). Complete resection of the first lymph node barrier was performed in 83% of patients, of the second in 7%; and of the third in none. Curative surgery was felt to have been performed in 37% of patients. These data suggest the need for earlier detection of gastric cancer in our population.

Adult↗
PubMed1989

Characterization of the ethenoadenosine diphosphate binding site of myosin subfragment 1. Energetics of the equilibrium between two states of nucleotide.S1 and vanadate-induced global conformation changes detected by energy transfer.

The fluorescence decay of 1,N6-ethenoadenosine diphosphate (epsilon ADP) bound to myosin subfragment 1 (S1) was studied as a function of temperature. The decay was biexponential, and the two lifetimes were quenched relative to the single lifetime of free epsilon ADP. The temperature dependence of the fractional intensities of the decay components showed two states of the S1.epsilon ADP complex. At pH 7.5 in 30 mM TES, 60 mM KCl, and 3 mM MgCl2, the equilibrium constant for the conversion of the low-temperature state (S1L.epsilon ADP) to the high-temperature state (S1H.epsilon ADP) was 40 at physiological temperatures, and delta H degrees = 13 kcal.mol-1 and delta S degrees = 49 cal.deg-1.mol-1. At 10 degrees C the equilibrium constant of S1 for epsilon ADP was 5, indicating that S1H.epsilon ADP was the dominant state, and that for the vanadate complex epsilon ADP.Vi was 0.7, suggesting that in S1.epsilon ADP.Vi the dominant state of the S1-nucleotide complex was converted from S1H.epsilon ADP to S1L.epsilon ADP. The single rotational correlation time of bound epsilon ADP at 10 degrees C decreased from 107 ns in S1.epsilon ADP to 74 ns in S1+.epsilon ADP.Vi. Conversion of the binary complex to the ternary vanadate complex resulted in a 3-A decrease in the energy transfer distance between bound epsilon ADP and N-[4-(dimethylamino)-3,5-dinitrophenyl]maleimide attached to SH1 and a decrease of the average distance between bound epsilon ADP and bound Co2+ from 12.6 to 8.3 A.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed1989

Differential scanning calorimetric study of the thermal unfolding of myosin rod, light meromyosin, and subfragment 2.

The thermal unfolding of myosin rod, light meromyosin (LMM), and myosin subfragment 2 (S-2) was studied by differential scanning calorimetry (DSC) over the pH range of 6.5-9.0 in 0.5M KCl and either 0.20 M sodium phosphate or 0.15M sodium pyrophosphate. Two rod samples were examined: one was purified by Sephadex G-200 without prior denaturation (native rod), and the other was purified by a cycle of denaturation-renaturation followed by Sephacryl S-200 chromatography (renatured rod). There were clearly distinguishable differences in the calorimetric behavior of these two samples. At pH 7.0 in phosphate the DSC curves of native rod were deconvoluted into six endothermic two-state transitions with melting temperatures in the range of 46-67 degrees C and a total enthalpy of 4346 kJ/mol. Under identical conditions the melting profile of LMM was resolved into five endothermic peaks with transition temperatures in the range of 45-66 degrees C, and the thermal profile of long S-2 was resolved into two endotherms, 46 and 57 degrees C. Transition 4 observed with native rod was present in the deconvoluted DSC curve for long S-2, but absent in the DSC curve for LMM. This transition was identified with the high-temperature transition detected with long S-2 and attributed to the melting of the coiled-coil alpha-helical segment of subfragment 2 (short S-2). The low-temperature transition of long S-2 was attributed to the unfolding of the hinge region. The smallest transition temperatures observed for all three fragments were 45-46 degrees C. It is suggested that the most unstable domain in rod (domain 1) responsible for the 46 degrees C transition includes both the hinge region, which is the C-terminal segment of long S-2, and a short N-terminal segment of LMM. This domain, accounting for 21% of the rod structure, contains the S-2/LMM junction, and upon proteolytic cleavage yields the C-terminal and N-terminal ends of long S-2 and LMM, respectively. Over the pH range of 6.5-7.5, the observed specific heat of denaturation of rod was approximately equal to the sum of the specific heats of LMM and S-2. This finding provides an additional argument for the existence of independent domains in myosin rod.

Animals↗
PubMed1989

[Obstetric and perinatal management of myasthenia gravis].

Three new cases of patients with myasthenia gravis during pregnancy are presented. The unpredictable course of myasthenia gravis (MG) in pregnancy is discussed. The course of labor in patients with MG is normal. The effects of certain drugs on the course of diseases are assessed. In our group of patients only one patient had an exacerbation of her MG after using an aminoglycoside. There were 7 live births. None of the newborns developed neonatal myasthenia.

Adult↗
PubMed1989

[Gestation of 42 weeks or longer. Management protocol].

We have evaluated, in a prospective approach to the perinatal results of 98 patients with gestation of 42 weeks and more. The patients with an uncertain gestation age were excluded. The vigilance of the fetus was realized by electronic monitorization, sonographic examination and amnioscopy 55.1% of patients begin labor spontaneously 44.9% were interrupted. The principals causes of interruption were pelvic score of bishop > 7 points and condition that suggest fetal injury. In 31.6% of patients a cesarean section was made. Neonatal morbidity was a 19.4% and we don't have mortality.

Adult↗
PubMed1986

Interaction of fluorescently labeled myosin subfragment 1 with nucleotides and actin.

Isolated myosin heads (subfragment 1) were modified by covalent attachment of 5-(iodoacetamido)fluorescein or 5-(iodoacetamido)salicylic acid to the essential sulfhydryl group SH1. The extrinsic fluorescence of the modified proteins was sensitive to binding of nucleotides and F-actin. With the fluorescein derivative [subfragment 1 (S1) modified with 5-(iodoacetamido)fluorescein (IAF) at SH1 (S1-AF)], association with MgADP decreased the probe fluorescence by 30%, whereas binding to actin increased the emission by a factor of 2. In the ternary complex acto-S1-AF X MgADP, the effect of nucleotide on the intensity of the attached fluorescein canceled the effect of actin. The fluorescence state of this ternary complex was similar to that of S1-AF X MgADP. The emission of S1-AF was resolved into two components with lifetimes of 4.3 and 0.6 ns and relative contributions of 33% and 67%, respectively. Interaction of S1-AF with nucleotides and actin did not alter the lifetimes but significantly shifted their fractional contributions. Quenching studies showed that the short lifetime likely arose from the fluorescein moiety statically quenched by internal groups. Binding of MgADP to the salicylate derivative [S1 modified with 5-(iodoacetamido)salicylic acid at SH1 (S1-SAL)] induced a 25% enhancement of the probe fluorescence, whereas formation of acto-S1-SAL decreased the emission by 10% regardless of whether MgADP was bound to the protein. Both labeled S1 species bound MgADP with a similar affinity, comparable to that of unmodified S1 previously reported by other investigators.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1986

Appearance of gas in renal tissue after therapeutic embolization.

We present a case of therapeutic embolization in a patient with adenocarcinoma who demonstrated the presence of gas in the renal infarcted tissue on the second day. The pattern of air distribution was intravascular. There was no sign of abscess clinically or radiographically. To the syndrome of postembolization we add a new sign--the presence of postembolization air.

Adult↗