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Biomedical subjects

G Juan

Publications and source records attributed to G Juan.

At least 55 records · Page 3Linked to original sources
PubMed1994

A fast kinetic method for assessing mitochondrial membrane potential in isolated hepatocytes with rhodamine 123 and flow cytometry.

Rhodamine 123 (Rh123) is widely used as a flow cytometric probe for mitochondrial membrane potential (MMP) in metabolic, pharmacologic, and toxicological studies. However, the use of relatively high concentrations of Rh123 (up to 10 micrograms/ml) and prolonged incubation times (up to 1 h), including washing steps, may be inconvenient for certain applications in which labile cells are used or which demand rapid or repeated analysis. In this paper we describe a rapid kinetic assay of MMP in isolated rat hepatocytes, based upon the quantitation of the initial rate of Rh123 uptake by living cells, selected by their scattering properties. The results indicate that at an appropriate dye-to-cell ratio (in our experiments, 50 ng Rh123/ml for 250,000-300,000 cells/ml), the initial rate of Rh123 uptake is a highly reproducible and sensitive parameter for estimation of MMP, as demonstrated by the effects of substrates and inhibitors of the glycolytic pathway and mitochondrial respiration. Because of its simplicity, rapidity (about 5 min) and metabolic implications, this assay would be also suitable for the routine evaluation of metabolic state of cell suspensions, as a complementary test to the standard dual-staining tests of viability. Other possible applications in screening pharmacologic and toxicological analysis are discussed.

Animals↗
PubMed1994

[Effects of CO2 on the rat diaphragm in vitro].

Acidosis produced by an increase in CO2 concentration decreases contractility and increases the tendency to fatigue in striated muscle. It is not clear a what levels of CO2 this effect takes place, or in what experimental models it can be observed. In this study we examine the effect of increasing concentrations of CO2 on contractility and fatigue in strips of rat diaphragm in vitro. Six strips of diaphragm from a rat of low-weight were kept in organ bath and supramaximal stimuli of 1, 10, 50 and 100 Hz were applied while CO2 concentration was changed from 5% (29 mmHg), to 10% (48.3 mmHg) to 20% (102 mmHg). To study fatigue we applied 45 series of 50 Hz stimuli per minute for 15 minutes. We obtained these results: a) Contractility. Force of contraction was less with 20% CO2 than with 5% under a stimulus of 1 Hz. No significant differences were found for other concentrations or frequencies. b) Fatigue. Force of contraction decreases as CO2 concentration increased and significant differences were found for all 3 concentrations. The conclusions were: a) an increase in CO2 from 5% to 20% produces a significant decrease in force of contraction under conditions of low-frequency stimuli and b) increases in CO2 concentration from 5% to 10 to 20% increase the muscle's susceptibility to fatigue.

Acidosis↗
PubMed1994

[The primary ciliary dyskinesia syndrome. A frequent pathology].

The prevalence of primary ciliary dyskinesia syndrome (PCDS) in Western countries is of 1/40,000 but is 13% in patients with bronchiectasis. The aim of this study was to determine the prevalence of PCDS in patients with bronchiectasis and sinusitis, including whether or not these patients present specific clinical signs. Eighteen patients with these two conditions from an area with 750,000 inhabitants in Valencia (Spain), were studied for 2 years. Radiologic and clinical information was recorded and mucociliary motility was measured with albumin marked with radioactive technetium. The structure of the nasal mucosa cilia was also studied. In 14 patients (77%) mucociliary motility was suppressed and in 13 ultrastructural changes typical of PCDS were observed. Only male infertility and situs inversus were more frequent in patients with PCDS; other clinical signs were equally severe and frequent in patients with PCDS and in those in whom no cause for bronchiectasis and sinusitis could be found. We conclude that 1) the prevalence of PCDS in patients with bronchiectasis and sinusitis is 77%; 2) in these patients a test of mucociliary motility is sufficient for diagnosis (structural study not being required); 3) the prevalence of PCDS in our population seems to be greater than that described; and 4) clinical signs are similar in patients with PCDS and in those with bronchiectasis of unknown genesis.

Adult↗
PubMed1994

Immotile cilia syndrome: nasal mucociliary function and nasal ciliary abnormalities.

We present 17 patients with a typical symptomatology of immotile cilia syndrome, seven of them with complete situs inversus. Firstly, a study of the nasal mucociliary transport was made by means of the radioisotopic technique with serum albumin-Tc99m. In all cases there was absence of transport. Secondly, we studied the ultrastructure of the nasal cilia. Defects in the dynein arms were frequently found (65%). In two cases (11%) there were no cilia; in two other cases the cilia were normal, and in another two cases alterations of the central pair of microtubules were seen. Ciliary complexes were detected in all cases. We conclude that in patients with chronic or recurrent infections of the airways without known cause we must initiate a study of the nasal mucociliary transport. If this is absent or decreased, study of ciliary ultrastructure should be carried out. If mucociliary transport is normal, immotile cilia syndrome is ruled out and ultrastructural study of the cilia is not required.

Adolescent↗
PubMed1993

[Tuberculosis and human immunodeficiency virus infection. A prospective study of 215 patients].

We analyze the cases of 215 adult patients affected from tuberculosis (TB) and infection due to human immunodeficiency virus (HIV) in the study period from December 6th, 1986 to January 31st of 1992. Disease affected specially the group of drug addict patients (DAP) with a 74.88%, followed by paid plasma donors (PPD) from our city with a 12.09%. Sexual transmission was the route of contamination with the HIV in 16 cases. In five cases atypical mycobacteria were detected. First-line anti-tuberculostatics drugs activity against Mycobacterium tuberculosis was excellent. A total of 17 cases with toxicity to any of these drugs were described. TB was located in the lung in 108 cases (50.23%), in 74 cases out of the lung (34.41%) and in 33 cases there was intrapulmonary as well as extrapulmonary affectation (15.34%). TB was diagnosed at the same time that a disease which met AIDS criteria in 13.49% of cases, TB was diagnosed first in 32.55% of cases, and AIDS was diagnosed before TB in only 7.91% of cases. Fever was the predominant symptom (88.84%), together with toxic status at admittance (80.47%) and deteriorated immune situation with lymphocytes count decrease (mean 1240/mm) and CD4 (mean value 134.5/mm) together with a mean raised IgA (492.85 mg/dl). Thorax radiography was normal in 34.88%. In 33 of these patients TB was localized in the lung, in 27.91% primary radiologic types were observed while in 31.16% reactivation types. In 51 cases (23.72%) tuberculosis was detected in patients (DAP) who were forwarded from the penitentiary system.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1992

Flow-cytometric enumeration of reticulocytes with the new fluorochrome 1,3'-diethyl-4,2'-quinolylthiacyanine (correction of 1',3'-diethyl-4,2'-quinolylthiacyanine)

Several flow-cytometric methods for reticulocyte enumeration in whole blood have been developed, with different degrees of practical use. Recently, a new fluorochrome, 1,3'-diethyl-4,2'-quinolylthiacyanine (corrected) (DEQTC) was proposed in a brief report, as an alternative to thiazole orange for reticulocyte counting. We have evaluated the usefulness of this fluorescent stain by assessing the optimal conditions for the flow-cytometric analysis, and by comparing in double-blind assays the quantitative results of this technique with those obtained by manual counting with brilliant cresyl blue. Our results show that flow cytometry with DEQTC is highly correlated to the manual method (r = 0.95-0.99), supporting the interest of this particular stain and of flow cytometry for routine laboratory work in hematology.

Anemia↗
PubMed1991

[Pulmonary tuberculosis with normal chest radiography and infection by human immunodeficiency virus].

We report 16 cases of pulmonary tuberculosis with normal chest x-ray film associated with infection by the human immunodeficiency virus (HIV). These patients belong to a sample of 125 cases of tuberculosis and HIV infection observed during the same study period. The clinical features and the diagnostic methods are described. The unusual character of the finding and its relevance are discussed, as the presentation of pulmonary tuberculosis with normal chest x-ray film was relatively common in patients with HIV infection (12.8%) in our series. This possibility should be considered in the whole population of patients with HIV infection.

False Negative Reactions↗
PubMed1985

Arterial CO2 partial pressure affects diaphragmatic function.

The purpose of this study was to examine in an in vivo preparation acute variations of PCO2 on diaphragmatic contractility. Plaster casts were snugly fit around the abdomen of six open-chested dogs, moving the abdominal contents rostrally. Diaphragmatic contractions against this very fixed load in response to phrenic nerve stimulation (supramaximal voltage at 1, 20, 50, and 80 Hz) or during spontaneous inspiratory efforts were virtually isometric (quasi-isometric). Transdiaphragmatic pressure (Pdi) measured by an abdominal balloon was used as an index of diaphragmatic contractility. Arterial PCO2 (PaCO2) was reduced by hyperventilation and raised by increasing PICO2. Pdi values in response to stimulation at 1, 20, 50, and 80 Hz in ranges I (PaCO2 = 0-19 Torr) and II (PaCO2 = 20-34 Torr) did not differ statistically from the control Pdi values (range III; PaCO2 = 35-45 Torr). In range IV (PaCO2 = 46-70 Torr) Pdi values for stimulations of 20, 50, and 80 Hz were significantly lower than control. In range V (PaCO2 = 71-90 Torr), VI (PaCO2 = 91-101 Torr), and VII (PaCO2 greater than or equal to 102 Torr) Pdi values were significantly less than those in range IV at all frequencies of stimulation. In the four dogs measured during spontaneous inspiratory efforts the integrated diaphragmatic electromyogram (Edi) was correlated with the Pdi. As PaCO2 rose (range III to VII), the Pdi values observed at 25, 50, 75, 100% of the maximum Edi (of range III) were significantly lower than the Pdi value of range III.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkalosis, Respiratory↗
PubMed1984

Effect of carbon dioxide on diaphragmatic function in human beings.

We studied the effects of acute changes in the partial pressure of arterial carbon dioxide on diaphragmatic contractility and performance in four normal men. To study contractility we measured the ability of the diaphragm to generate pressure at a given level of excitation by determining the relation between the electrical activity of the diaphragm and transdiaphragmatic pressure during a voluntary quasi-isometric inspiratory effort carried out at different levels of end-tidal carbon dioxide. Our results show that contractility was reduced with hypercapnia (when end-tidal carbon dioxide was 7.5 per cent or higher), although hypocapnia (end-tidal carbon dioxide, 3 per cent) had no effect on diaphragmatic contractility. We also studied the development of diaphragmatic fatigue before and during carbon dioxide breathing. Subjects were studied at the same diaphragmatic tension-time index, a value analogous to the more familiar myocardial tension-time index, while the same inspiratory flow was maintained. Electromyographic signs of fatigue appeared at a lower tension-time index during hypercapnia than during normocapnia, indicating that endurance is diminished during hypercapnia. These findings show that acute respiratory acidosis equivalent to an arterial carbon dioxide tension of about 54 mm Hg decreases the contractility and endurance time of the diaphragm in human beings.

Carbon Dioxide↗
PubMedDate not supplied

Influence of low temperature on bronchodilatation induced by terbutaline administered by metered dose or dry powder inhalers in asthmatics.

Low temperatures may affect dose delivery efficacy and clinical effectiveness of medication aerosols. In this study we examine the effect of cold ambient temperature on the bronchodilatation produced by terbutaline delivered from a chlorofluorocarbon pressurized metered dose inhaler (pMDI) compared to a multi-dose dry powder inhaler (DPI). Fourteen stable asthmatics were studied on two consecutive days. On day 1, after measuring FEV1 at room temperature (22 degrees C), each patient was randomized to receive 500 microg of terbutaline delivered from pMDI or DPI stored for 24 h at 22 degrees C with FEV1 recorded 20 min post-dose; then, patients were placed in a chamber at -10 degrees C, and after obtaining FEV1, each patient received 500 microg of terbutaline delivered from pMDI or DPI (same formulation as previously administered) stored for 24 h at -10 degrees C, and FEV1 was obtained 20 min post-dose. On day 2, a similar protocol was followed but each patient received terbutaline as the alternative to the formulation administered on day 1. Pairwise comparisons of the FEV1 (% predicted) values obtained on day 1 and day 2 at 22 degrees C and -10 degrees C (pre-dose) showed no significant differences. Similar bronchodilatations were observed for terbutaline DPI administration at 22 degrees C and -10 degrees C (24.85 +/- 11.72 and 20.08 +/- 6.27% increase of FEV1; P > 0.05). By contrast, the bronchodilatation obtained for terbutaline pMDI at 22 degrees C (21.07 +/- 8.55% increase in FEV1) was not reproduced at -10 degrees C (0.72 +/- 2.84%; P < 0.05 from 22 degrees C). In five asthmatics a cumulative dose-response curve for terbutaline pMDI was obtained. This part of the study showed that a higher dose of terbutaline pMDI was necessary at -10 degrees C to obtain a bronchodilator response (10.04 +/- 6.75% increase of FEV1 after 2,000 microg) that remained lower than the bronchodilatation for 500 microg terbutaline pMDI at -10 degrees C. In conclusion, the clinical effectiveness of terbutaline delivered from chlorofluorocarbon pMDIs is compromised by cold storage while DPIs are not affected.

Administration, Inhalation↗
PubMedDate not supplied

[Brachytherapy results in prostatic cancer].

OBJECTIVE: To analyze the 15-year results of external irradiation combined with radioactive gold grain implantation (Au198) in the treatment of adenocarcinoma of the prostate and to discuss the therapeutic perspectives. METHODS: The present study was conducted on 23 patients with localized prostate carcinoma (17 stage B; 6 stage C) that had been diagnosed and treated at our department from February 1981 to October 1986. The mean patient follow-up was 90.96 months. Au198 implantation (mean dose 3347.6 cGy) was performed through the abdominal approach prior to external irradiation (mean dose 39 Gy) with Co-60 (19 patients) or the 18-MV photon linear accelerator (4 patients). The mean fractionated dose was 180.43 cGy/day. RESULTS: Overall the 15-year locoregional control rate was 61% and disease-free survival was 38%. The overall survival rate was 25%, regardless of the cause of death. The tumor control rate was 61% for stage B and 83% for stage C lesions at 15 years. The disease-free survival rate was 40% for stage B and 50% for stage C tumors. The local control and disease-free survival rates were worse for patients in whom the diagnosis had been made by TUR (p = not significant). CONCLUSIONS: The locoregional tumor control and disease-free survival rates for this group of 23 patients who received combined therapy with external irradiation and radioactive gold grain implantation (Au198) were slightly lower than those obtained in another group of 104 patients treated at our Service of Radiotherapeutic Oncology with radical external radiation therapy and can be ascribed mainly to poor patient selection and inadequate radiation dose.

Adenocarcinoma↗