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R Robles

Publications and source records attributed to R Robles.

At least 127 records · Page 7Linked to original sources
PubMed1997

Correlation of the suppressive activity of a biological response modifier on the proliferation of peripheral blood mononuclear cells and the reduction of HIV titer.

Activation of CD4+ cells is a prerequisite for infection by the human immunodeficiency virus (HIV). Thus, any agent capable of suppressing CD4+ cell proliferation could create a refractory stage that would impede viral infection. We have reported, in a previous publication, that a biological response modifier (BRM), polyantigenic immunomodulator (PAI) substantially reduces HIV-1 titer (from 20 to 100%) in peripheral mononuclear cells (PBMC) cultures with high viral titer (p24 = 10(2)-10(5) pg/ml). We are presenting data suggesting that the reported reduction in virus titer seems to be associated with a suppressive activity of PAI on the proliferation of PBMC from intravenous drug users (IVDU) infected and non-infected with HIV-1. PAI, a well characterized BRM, is a mixture of inactivated bacterial and influenza virus vaccines. PBMC from healthy donors and IVDU individuals were exposed to PAI, phytohemagglutinin (PHA), interleukin-2 (IL-2) and to combinations of PAI with either PHA or IL-2. Appropriate controls were included. 3H-thymidine pulsing was used as indicator of cell proliferation. The stimulation index and the difference between mean cpm of test sample and control were used to measure proliferative activity. There was a low proliferative response in the PBMC cultures from IVDU and HIV-1 positive patients, but it was substantially lower in the later group. When PBMC cultures from the same group of individuals were exposed to PAI, PHA and IL-2, and to the combination of either PAI plus PHA or IL-2, the response observed in the PAI treated group was uniformly lower than in the other treated cultures. Moreover, when PAI was combined with PHA, it exerted a significant reduction in the measured parameters. The effect of PAI on IL-2 activity was negligible. A suppressive effect of a PAI has been detected on the proliferation of PBMC from IVDA and HIV-1 positive individuals. This activity may be associated with the capacity of PAI to reduce HIV titers in infected PBMC cultures.

Adjuvants, Immunologic↗
PubMed1996

Partial purification and characterization of a protease from human plasma cleaving von Willebrand factor to fragments produced by in vivo proteolysis.

Proteolytic cleavage of von Willebrand factor (vWF) takes place in the circulating blood of healthy subjects and is increased in some patients with von Willebrand disease type 2A. The hemostatically active large vWF multimers are degraded to smaller less active forms. It has been suggested that the polypeptide subunit of vWF is cleaved at the peptide bond 842Tyr-843Met. We purified (approximately 10,000-fold) from human plasma a vWF-degrading protease, using chelating Sepharose, hydrophobic interaction chromatography, and gel filtration. The enzyme was found to be virtually absent in the platelet lysates obtained by repeated freezing and thawing. The proteolytic activity was associated with a high molecular weight protein (approximately 300 kD) as judged by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. vWF was resistant against the protease in a neutral buffer at physiological ionic strength but became degraded at low salt concentration or in the presence of 1 mol/L urea. No degradation of human fibrinogen, bovine serum albumin, of calf skin collagen by the purified protease was noted under the same experimental conditions. Proteolytic activity showed a pH optimum at 8 to 9 and was strongly inhibited by chelating agents, whereas only slow inhibition was observed with N-ethylmaleimide. There was no inhibition by iodoacetamide, leupeptin, or serine protease inhibitors. The best peptidyl diazomethyl ketone inhibitor was Z-Phe-Phe-CHN2. Activation by divalent metal ions was found to increase in the following order: Zn2+ approximately Cu2+ approximately CD2+ approximately Ni2+ approximately Co2+ <Mn2+ <Mg2+ <Ca2+ <Sr2+ <Ba2+. The observed properties of the vWF-degrading enzyme differ from those of all other hitherto described proteases. Purified vWF was incubated with the protease, and the degraded material subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis after disulfide reduction. The size, amino acid composition, and amino terminal sequence of the reduced fragments confirmed that the peptide bond 842Tyr-843Met had been cleaved, ie, the same bond that has been proposed to be cleaved in vivo.

ADAM Proteins↗
PubMed1996

Serum ionized magnesium monitoring during orthotopic liver transplantation.

During orthotopic liver transplantation (OLT) citrate accumulates and magnesium can be chelated, which can lead to ionized hypomagnesemia and cardiovascular dysfunction. Our aim was to study the serum ionized magnesium (Me2+) evolution and establish its relation to serum total Mg and citrate levels during OLT. We studied 58 adult patients undergoing OLT. The serum Me2+ level dropped significantly at the end of the preanhepatic phase, and remained low until the end of the procedure. Furthermore, the Me2+ levels remained below the range of reference from the beginning of the anhepatic phase onward. There was an inverse correlation between Me2+ and citrate for all patients. Me2+, like ionized calcium (Ca2+), is chelated by citrate and its evolution is a mirror image of that of citrate. In our patients, we did not observe any significant dysrhythmias that could be directly attributed to ionized hypomagnesemia. In conclusion, low preoperative levels, together with the massive transfusion of blood products and the increase in renal losses, cause progressive ionized hypomagnesemia in OLT patients. We propose that it he routinely monitored and treated accordingly, as is already done with Ca2+.

Adolescent↗
PubMed1996

Effects of cold ischemia time on the graft after orthotopic liver transplantation. A bile cytological study.

We conducted a daily analysis of bile cellularity in 16 orthotopic liver transplant patients fitted with a T-tube, and correlated the cytological parameters (number of cells per slide, and percentage of difference cell types) with the duration of cold ischemia time (CIT). Two groups were established: one comprised patients whose CIT was less than 7 hr (CIT averaged 345 min) and the other comprised patients with a CIT of more than 7 hr (CIT averaged 505 min). The control group consisted of 15 patients who had received cholecystectomy for biliary lithiasis and were fitted with a T-tube. All 3 groups showed the highest cell density on the 1st postoperative day (control: 53.3 +/- 15.5 cells/slide; short ischemia: 70 +/0 21.4 cells/slide; long ischemia: 158.8 +/- 53.2 cells/slide), which steadily ischemia group showed a higher cell density than did the control group for the first 2 days, although this was not significant. The long ischemia group showed the highest cell density, although only significantly for the first 2 days when compared with the controls, and basically at the expense of a increase in ductal epithelial cells. Our results show that prolonged cold ischemia causes an increase in bile cell density at the expense of ductal epithelial cells: the longer the preservation time, the greater the increase.

Adolescent↗
PubMed1996

Influence of obstetric and perinatal care on perinatal mortality.

OBJECTIVE: Cases of perinatal death attributed to suboptimal perinatal care between 1979 and 1992 inclusive at a large, tertiary care center are reviewed. STUDY DESIGN: The study compared two periods: 1979-1985 and 1986-1992. The perinatal morbidity-mortality committee analyzed patient records for the mothers and neonates, delivery room records, the results of fetal autopsy, and histological sections of the placenta. RESULTS: In the first period, 21.5% of the deaths were found to have received suboptimal care; this figure declined 13.5% in the second period (P < 0.05). During the second period, antenatal, intranatal and postnatal care improved, as shown by the lower suboptimal care rate for antepartum (15.8% versus 9.8%; P < 0.05), intrapartum (49.2% versus 22.1%; P < 0.001) and postpartum death (19.9% versus 8.1%; P < 0.001). During both periods, fetal death during pregnancy made up the largest proportion of deaths attributed to suboptimal care, with 44 cases (43.1%) during 1979-1985, and 36 cases (64.3%) during 1986-1992 (P < 0.01). Of these cases, fetuses with intrauterine growth retardation were the most frequent recipients of suboptimal care (20 cases (45.5%) during the first period; 18 cases (50%) during the second period). CONCLUSION: Despite better prenatal care, the highest suboptimal care rate was due to suboptimal care during pregnancy, when some high risk situations were overlooked by the obstetrician.

Cesarean Section↗
PubMed1995

Clinical improvement after liver transplantation for type I familial amyloid polyneuropathy.

Long-term results of 13 liver transplantations in patients with a previous diagnosis of type I familial amyloid polyneuropathy (FAP) are presented. The diagnosis of type I FAP was based on the presence of a biochemical marker in the plasma (TTR-Met-30 in 11 patients, TTR-Ala-71 in two). Maximum follow-up is 28 months and the survival rate stands at 11 of 13 patients. Two patients died from sepsis at 2 and 6 months. TTR disappeared from plasma in all cases. Neurological status improved in all eight patients undergoing transplantation more than 6 months previously, although electromyographic studies showed a slight improvement only in the six with follow-up of more than 1 year. All 13 patients showed a hyperdynamic haemodynamic pattern with a high incidence (four patients) of the use of venovenous bypass due to haemodynamic intolerance. Two patients also received transplants by the 'piggy-back' technique. In conclusion, liver transplantation may be useful in the treatment of certain patients with FAP to halt and improve the neurological consequences of the disease.

Adult↗
PubMed1995

Laparoscopic cholecystectomy in the treatment of acute cholecystitis.

BACKGROUND: Laparoscopic cholecystectomy has several advantages over traditional cholecystectomy, which make it the treatment of choice for patients with uncomplicated biliary lithiasis. However, in patients with acute cholecystitis, the role of this technique remains controversial and some clinicians regard this condition as a contraindication to laparoscopic cholecystectomy. STUDY DESIGN: Between June, 1991 and July, 1993, a total of 259 patients with cholelithiasis underwent laparoscopic cholecystectomy at the "Virgen de la Arrixaca" University Hospital. Of these patients, 60 underwent laparoscopic cholecystectomy for acute cholecystitis. RESULTS: Conversion to laparotomy was necessary in eight patients (13 percent). Mean operating time was 83 minutes (range, 45 to 180 minutes). Overall mean hospital stay (laparoscopy and conversions) was 3.1 days (range, one to nine days). There was no mortality or injury to the common bile duct in our series. CONCLUSIONS: We believe that laparoscopic cholecystectomy in patients with acute cholecystitis is a safe and effective procedure, in which the patient can benefit from the advantages of laparoscopic surgery without an increase in mortality and morbidity rates.

Acute Disease↗