PubMed Health⌕ Search

Biomedical subjects

J A Lorente

Publications and source records attributed to J A Lorente.

At least 73 records · Page 4Linked to original sources
PubMed1994

Analysis of short tandem repeat (STR) HUMVWA in the Spanish population.

Amplification by polymerase chain reaction (PCR) of variable number of tandem repeat (VNTR) loci and subsequent typing by electrophoresis and silver staining has become a useful tool for identity testing. One viable group of genetic markers amenable to amplification by PCR is the short tandem repeat (STR) loci. A horizontal discontinuous polyacrylamide gel electrophoresis (PAGE) method was used to type the amplified products of the STR HUMVWA. Typing for VWA of 120 unrelated Spanish Caucasians was done. Six alleles were observed with frequencies in the range 0.096-0.242. The genotype distribution meets Hardy-Weinberg expectations (0.25 < P < 0.50). The heterozygosity was 73.3% and the discrimination power (DP) 0.94. Simultaneously, in a small sample of families (n = 24) no new mutations could be found.

Alleles↗
PubMed1994

Sequential multiplex amplification (SMA) of genetic loci: a method for recovering template DNA for subsequent analyses of additional loci.

A method called Sequential Multiplex Amplification (SMA) has been developed whereby a limited amount of DNA extracted from a sample can be reutilized for several single polymerase chain reaction (PCR) amplifications. The method involves recovery of genomic template DNA by microfiltration of PCR-amplified samples. Up to 5 different loci have been typed, each in a single system PCR-based assay, beginning with a test quantity of 5 ng template DNA. Genotypes of the DNA donors were compared with those obtained from individual amplifications and shown to be identical. This could be a useful technique for typing a number of loci from a limited amount of DNa and to recover template DNA from samples previously subjected to PCR. Obviously, when small quantities of template DNA are available, this technique can prove quite useful.

Base Sequence↗
PubMed1994

Inhibition of nitric oxide synthesis improves the vasoconstrictive effect of noradrenaline in sepsis.

BACKGROUND: Septic shock is characterized by systemic vasodilation and an impaired reactivity to vasoconstrictor agents. It has been suggested that an excessive release of nitric oxide has a role in this hemodynamic derangement. OBJECTIVE: To investigate whether inhibition of nitric oxide synthesis by the administration of N omega-nitro-L-arginine (LNNA), improves the vasoconstrictor effects of catecholamines in sepsis. MATERIAL AND METHODS: Mechanically ventilated and pentobarbital-anesthetized sheep received either no treatment (n = 6) or LNNA (100 mg/kg IV bolus, n = 4). Other sheep (septic group) received live Escherichia coli (E coli) (1,5* 10(9) micro-organisms/kg over 30 min) followed 1 hour later by either no treatment (n = 5) or LNNA (100 mg/kg IV bolus, n = 7). After those interventions, all sheep were given noradrenaline in a continuous IV infusion at three different doses (0.5, 1.5, and 4.5 micrograms, kg-1, min-1). Cardiovascular parameters were recorded at maximal blood pressure response achieved with each dose. RESULTS: The administration of live E coli to the septic group resulted in systemic hypotension, high cardiac output, and hyperlactatemia. The LNNA caused a significant systemic and pulmonary vasoconstriction in both septic and nonseptic sheep. In nonseptic sheep, noradrenaline induced a significant increase in systemic vascular resistance (from 2,973 +/- 637 to 4,561 +/- 1,287 dyn/s/cm-5/m-2), whereas the increase caused in those that received LNNA was nonsignificant (5,562 +/- 3,489 to 6,693 +/- 2,871 dyn, s, cm-5, m-2). Septic sheep showed a nonsignificant vasoconstriction during the infusion of noradrenaline (from 1,438 +/- 1,132 to 2,244 +/- 1,391 dyn/s/cm-5/m-2). However, treatment with LNNA markedly improved the vasoconstrictor effect of noradrenaline (from 2,804 +/- 2,317 to 4,894 +/- 3,435 dyn/s/cm-5/m-2). The dose-response curve of systemic vascular resistance in these LNNA-pretreated septic sheep became very similar to the corresponding curve obtained in nonseptic animals. CONCLUSIONS: Inhibition of nitric oxide synthesis by the administration of LNNA significantly improves the vasoconstrictor effect of noradrenaline in septic sheep, allowing an increase in systemic vasomotor tone similar to that observed in nonseptic sheep. It is concluded that increased synthesis of nitric oxide contributes to the depressed vascular reactivity to vasoconstrictor agents characteristic of sepsis.

Animals↗
PubMed1994

[The clinical and prognostic value of inversion of the PSA/PAP ratio in prostatic cancer].

The inversion of PSA/PAP ratio is not common in patients with prostate cancer. Of 215 patients, 7 showed PSA levels below those of PAP (3.2%). All patients had metastatic disease at the time of diagnosis, 57% in multiple organs and tissues, with a Gleason value in all cases 4. Forty-three percent showed no early response to hormone therapy; mean survival interval recorded in these 7 patients was 21 months. Such a situation may suggest a poor prognosis for this neoplasia.

Acid Phosphatase↗
PubMed1994

[Prostate-specific antigen as an evaluation method in the treatment of hormone-refractory cancer of the prostate].

Out of 62 patients with hormone-refractory metastatic prostate cancer, 34 received rescue treatment with estramustine phosphate and 28 received non-steroidal symptomatic treatment. All patients undergoing symptomatic treatment experienced increased PSA levels while in 16 (47%) patients treated with estramustine phosphate, PSA decreased between 13-96%. In 11 cases (32.3%) the decline in PSA was higher than 50%. In 5 (14.7%) the decline was lower than 50% and in 18 cases (53%) PSA levels were increased. SCR rate was 82%, 60% and 6% respectively while OCR were 36.4%., 0% and 0% respectively. No clinical response was seen in patients undergoing symptomatic treatment. A decline in PSA levels higher than 50% 12 weeks after treatment appears to be a "good prognosis" factor related to the best clinical response rates and survival.

Estramustine↗
PubMed1994

[The concept of biologic progression in metastatic cancer of the prostate hormonally treated].

A total of 110 patients with hormone-treated metastatic prostate cancer were monitored quarterly with serial PSA determinations. At the first control, 6 patients had progressed clinically, 5 of which had decreased PSA ranging between 9-77%. After a period of response, 69 patients progressed clinically, of which 1 showed no elevation of PSA levels, 14 showed progression concurrent with PSA increase, and 54 showed a period of gradual elevation of PSA over a range of 2-31 months. The probability of biological progression when the first rise occurred ranged between 72-96%, which after a second increase ranged between 92-100%, and all patients with three consecutive increases progressed clinically.

Androgen Antagonists↗
PubMed1994

Analysis of the HUMTH01 allele frequencies in the Spanish population.

Genetic marker typing based on DNA amplification by the polymerase chain reaction (PCR) increasingly is being employed in forensic casework and for paternity testing. The allele frequencies were determined using PCR for 120 unrelated Spanish Caucasians for the locus HUMTHOH1. Six alleles were observed, with frequencies ranging from 0.013 (allele 11) to 0.254 (allele 10). The observed heterozygosity was 75.8%, and the power of discrimination is 0.92. The genotype distribution meets Hardy-Weinberg expectations.

Alleles↗
PubMed1993

Composite PAGE: an alternate method for increased separation of amplified short tandem repeat alleles.

Genetic typing of short tandem repeat (STR) loci may require electrophoretic separation techniques which, depending on the locus, can resolve alleles differing in size by only 2, 3 or 4 base pairs (bps). Many such loci can be separated by horizontal, discontinuous polyacrylamide gel electrophoresis (hd-PAGE). However, some loci present particular separation challenges. A composite (or step) gel system consisting of 2 zones, anodal and cathodal, which differ by pore size and ionic strength, has been developed to augment resolution of DNA fragments without a need for additional electrophoretic equipment. Depending on pore size, as well as ionic strength, initial migration can be increased or decreased to effect resolution. When compared with hd-PAGE, this composite gel electrophoretic system can result in enhanced resolution of PCR amplified STR alleles.

Actins↗
PubMed1993

Cathepsin D as a vitality marker in human skin wounds.

This paper shows the results obtained by studying the lysosomal enzyme Cathepsin D as a potential marker for the vitality of wounds in human specimens. We have analyzed 53 samples using enzymological and histological techniques. Our results show the ability of Cathepsin D to establish the vital origin of wounds inflicted 5 minutes or less before death, where the specific activity of cathepsin D reached 0.055 units at the wound edge and 0.01 units in their respective controls (P < 0.001). As previously demonstrated in an experimental series, Cathepsin D seems to be a very useful marker of high forensic interest in especially difficult cases. Further studies are in progress to check the influence of different factors such as drugs intake and clinical conditions on Cathepsin D activity.

Adolescent↗
PubMed1993

Role of nitric oxide in the hemodynamic changes of sepsis.

OBJECTIVE: To study the role of nitric oxide in the hemodynamic changes of sepsis. DESIGN: Prospective, randomized, controlled, intervention study. SUBJECTS: Twenty-five sheep randomized to four groups: Group A (n = 8, nonseptic sheep) received NG-nitro L-arginine (20 mg/kg i.v.) followed 15 mins later by L-arginine (200 mg/kg i.v.); group B (n = 4, nonseptic sheep) received L-arginine followed 15 mins later by NG-nitro L-arginine; group C (n = 7, septic sheep) received NG-nitro L-arginine (20 mg/kg i.v.) alone; group D (n = 6, septic sheep) received L-arginine (200 mg/kg i.v.) followed by NG-nitro L-arginine (20 mg/kg i.v.). INTERVENTIONS: Sheep were anesthetized with pentobarbital, mechanically ventilated and monitored with a pulmonary artery catheter, a peripheral artery catheter, and a Miller catheter in the left ventricle. Sepsis was induced by the intravenous administration of live Escherichia coli (1.5 x 10(9) microorganisms/kg over 30 mins), which resulted in systemic hypotension, pulmonary hypertension, high cardiac output, and hyperlactatemia. Acetylcholine was administered before and after each intervention. MEASUREMENTS AND MAIN RESULTS: In nonseptic sheep (groups A and B) NG-nitro L-arginine induced an increase in mean blood pressure (BP), pulmonary arterial pressure, and systemic and pulmonary vascular resistances, accompanied by a decrease in cardiac index and the first derivative of left ventricular pressure. L-arginine administered to normal sheep induced systemic vasodilation. In the sepsis groups (groups C and D), the increases in BP and systemic vascular resistances induced by NG-nitro L-arginine were significant but less marked than in nonseptic sheep. Pretreatment of septic sheep with L-arginine totally abolished the NG-nitro L-arginine induced increases in systemic and pulmonary vascular resistances in this group. The administration of L-arginine in these animals induced both systemic and pulmonary vasodilation. Acetylcholine-mediated vasodilation was severely impaired in sepsis. In this condition, pretreatment with L-arginine improved the response to acetylcholine. CONCLUSIONS: These data support the view that nitric oxide plays a significant role in modulating systemic and pulmonary vasomotor tone in normal and septic sheep. L-arginine produced systemic vasodilation in normal sheep, whereas both systemic and pulmonary vasodilation were observed in septic animals. The impaired response to an endothelium-dependent vasodilator in sepsis was improved by the previous administration of L-arginine.

Acetylcholine↗
PubMed1993

L-arginine pathway in the sepsis syndrome.

OBJECTIVE: To investigate the role of nitric oxide in the regulation of vascular tone in patients with the sepsis syndrome. DESIGN: Prospective, intervention study. SETTING: Tertiary care hospital. PATIENTS: Fifteen patients admitted to our medical intensive care unit with the diagnosis of sepsis syndrome by defined criteria. INTERVENTIONS: Eight patients received N omega-nitro-L-arginine (20 mg/kg, iv bolus) followed by L-arginine (200 mg/kg, iv bolus). Seven patients received L-arginine alone (200 mg/kg). MEASUREMENTS AND MAIN RESULTS: In the first group, hemodynamic and oxygen transport variables were recorded at baseline, during 45 mins after the injection of N omega-nitro-L-arginine, and during 45 mins after the administration of L-arginine. In the second group, hemodynamic parameters were recorded at baseline and during 15 mins after the administration of L-arginine. Data are mean +/- SEM. The administration of N omega-nitro-L-arginine was followed by hypertension (mean blood pressure increased from 89 +/- 8 to a maximum of 140 +/- 12 mm Hg) accompanied by a decrease in cardiac index (from 3.51 +/- 0.39 to a minimum of 2.65 +/- 0.21 L/min/m2) and an increase in right atrial and pulmonary artery occlusion pressure. Systemic vascular resistance index increased from 1871.1 +/- 302.3 to 3825.6 +/- 244.4 dyne.sec/cm5.m2, and pulmonary vascular resistance increased from 533.2 +/- 125.8 to 816.0 +/- 117.3 dyne.sec/cm5.m2. These changes induced by N omega-nitro-L-arginine were reversed by the administration of L-arginine. The administration of L-arginine to another group of patients caused transient hypotension (from 103 +/- 6 to 81 +/- 10 mm Hg) and an increase in cardiac index (from 3.57 +/- 0.15 to 4.74 +/- 0.54 L/min/m2). Both systemic and pulmonary vascular resistance indices decreased (from 1987.6 +/- 163.9 to 1251.4 +/- 231.5 dyne.sec/cm5.m2, and from 486.1 +/- 65.2 to 380.5 +/- 70.3 dyne.sec/cm5.m2). Parallel to the increase in oxygen transport due to the increase in cardiac output, oxygen consumption index increased significantly 1 min after L-arginine (from 127.0 +/- 19.0 to 182.5 +/- 37.3 mL/min/m2). All mentioned changes were statistically significant (p < .05). CONCLUSIONS: A continuous basal release of nitric oxide plays a role in the regulation of systemic and pulmonary vascular tone in patients with sepsis syndrome. L-arginine has systemic and pulmonary vasodilatory actions.

Aged↗
PubMed1993

Effects of blood transfusion on oxygen transport variables in severe sepsis.

OBJECTIVE: To investigate whether increasing oxygen delivery (DO2) by increasing hematocrit results in increases in oxygen uptake (VO2) in septic patients with an abnormal DO2/VO2 relationship. DESIGN: Prospective, randomized, interventional crossover study. SETTING: Tertiary care hospital. PATIENTS: A consecutive sample of 16 patients admitted to the intensive care unit, who were diagnosed as having severe sepsis by defined criteria and who had a hemoglobin concentration of < 10 g/dL. INTERVENTIONS: Patients received, in random order, an infusion of dobutamine (10 micrograms/kg/min) and a blood transfusion (800 mL of packed red blood cells in 90 mins). Hemodynamic and oxygen transport variables were determined before and after each treatment, allowing at least 20 mins during the infusion of dobutamine to achieve the steady state. MEASUREMENTS AND MAIN RESULTS: Changes in DO2 and VO2 induced by each intervention were measured. Dobutamine significantly increased DO2 (48.5 +/- 6.9%; p = .0001) and VO2 (21.7 +/- 3.3%; p = .0001). Blood transfusion increased DO2 (21.4 +/- 4.3%; p = .005) but VO2 did not change significantly (2.2 +/- 4.1%). Correlation coefficients for the percent changes of DO2 and VO2 (r2 = .67, p = .001 for dobutamine; and r2 = 21, p = .07 for blood transfusion) were significantly different for each treatment (p = .0001). CONCLUSIONS: In patients with an abnormal DO2-dependent VO2, as shown by increases in VO2 brought about by an infusion of dobutamine, blood transfusion does not significantly increase VO2, despite significant changes in DO2. The VO2, in some critically ill patients, depends more on blood flow than on global DO2.

Blood Gas Analysis↗
PubMed1993

Time course of hemostatic abnormalities in sepsis and its relation to outcome.

OBJECTIVES: To investigate the time course and the relation to prognosis of coagulation and fibrinolytic abnormalities in patients with septic shock. PATIENTS AND METHODS: Forty-eight consecutive patients admitted to the medical ICU with the diagnosis of septic shock (diagnosed by defined criteria) were studied. Mortality was 25 of 48. Mean age was 57 +/- 7.3 years. Blood samples were obtained on days 1, 4, and 7 after hospital admission to measure tissue-type plasminogen activator antigen (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitor antigen (PAI-1), plasminogen, alpha 2-antiplasmin, fibrinogen, antithrombin III, protein C, protein S, thrombin-antithrombin complexes (TAT), D-dimer, and von Willebrand factor-related antigen (vWF:Ag). RESULTS: All patients showed marked abnormalities in both the coagulation and fibrinolytic systems. There were signs of coagulation activation and elevation of both activators and inhibitors of fibrinolysis. Nonsurvivors showed lower levels of protein C and antithrombin III and higher concentration of TAT than survivors. While both t-PA and PAI-1 concentrations were high in survivors and nonsurvivors, only survivors showed a progressive normalization of both parameters during the study period. Low plasminogen levels and plasminogen/alpha 2-antiplasmin ratio were found in both groups, presenting a trend toward normalization only in survivors. The differences reported were not apparent at the time of hospital admission. CONCLUSIONS: Septic shock is characterized by coagulation activation and fibrinolysis activation and inhibition. Nonsurvivors present a particular hemostatic profile characterized by a more marked activation of coagulation and a more intense inhibition of fibrinolysis. None of the abnormalities studied was significantly different between survivors and nonsurvivors at the time of hospital admission. In the presence of fibrin formation, nonsurvivors present a maintained imbalance in the fibrinolytic response determined by higher PAI-1 plasma concentration, probably contributing to their poor outcome.

Antithrombin III↗
PubMed1993

Hemodynamic effects of oxygen therapy in patients with acute exacerbations of chronic obstructive pulmonary disease.

The effects of oxygen therapy in patients with stable COPD have been previously reported; however, the hemodynamic changes induced by oxygen therapy in patients during acute exacerbations of COPD are less well known. To investigate the hemodynamic effects of controlled oxygen therapy in patients with acute exacerbations of COPD shortly after arriving at the hospital, we studied 15 consecutive patients who came to the emergency room with acutely decompensated COPD that did not require mechanical ventilation. Patients were monitored with a pulmonary artery catheter and a radial artery catheter. Oxygen uptake was calculated by the modified Fick equation. Arterial and venous blood gas levels and hemodynamic parameters were measured while breathing room air (baseline) and after 30 min on oxygen therapy via face mask. Measurements were repeated after 24 and 48 h. The fractional concentration of oxygen in the inspired gas (FIO2) administered was adjusted to keep the PaO2 above 55 mm Hg. All patients had a PaO2 below 45 mm Hg at the beginning of the study. After 30 min of oxygen therapy, there was a significant (p < 0.05) increase in arterial oxygen saturation (from 62 +/- 16 to 87 +/- 9 percent), mixed-venous oxygen pressure (from 25 +/- 5 to 43 +/- 11 mm Hg), and oxygen delivery (from 11.1 +/- 3.7 to 19.3 +/- 8.9 ml/kg.min). Oxygen uptake did not change significantly (from 4.1 +/- 1.2 to 4.3 +/- 1.6 ml/kg.min). The oxygen extraction ratio decreased from 37.5 +/- 10.1 to 25.3 +/- 9.6 percent. These changes were maintained during the following 48 h. There were no significant changes in cardiac output and systemic vascular resistance. A trend toward lower values of pulmonary vascular resistance did not reach statistical significance. We conclude that oxygen therapy in patients with acute exacerbations of COPD that do not require mechanical ventilation increases oxygen delivery without changes in cardiac output or oxygen uptake.

Acute Disease↗
PubMed1992

[The effects of prostacyclin on oxygen transport in adult respiratory distress syndrome].

BACKGROUND: Patients with the adult respiratory distress syndrome (ARDS) present a deficit of tissue oxygenation which may be unmasked if increases in oxygen uptake (VO2) are observed when increases in oxygen delivery (DO2) are induced. Prostacyclin is a drug to which microvasodilator effects have been attributed and it has been proposed as an efficient agent for increasing histic enhancement of oxygen. METHODS: An infusion of prostacyclin was administered to 13 patients diagnosed with ARDS at doses of 10, 20, and 30 ng/kg per minute monitored with a Swan-Gatz catheter. RESULTS: The values are expressed as the percentage median of the increase with p less than 0.05 being considered as statistically significant. Prostacyclin significantly increased DO2 (10, 18 and 15% at the different doses). The VO2 rose significantly only following the first dose (13%). There was a correlation between the increase of DO2 and that of VO2 following the administration of the first dose (r = 0.70, p = 0.017. An important systemic vasodilator and pulmonary effect was observed accompanied by increases in the pulmonary (20, 56 and 59%) and reductions of PaO2 (-33.5, -40 and -48%) which may have been due to inhibition of hypoxic vasoconstriction. CONCLUSIONS: Prostacyclin is efficient for unmasking a lack of oxygen in patients with adult respiratory distress syndrome. The deleterious effects of this drug on systemic hemodynamics and on gaseous interchange makes not only the monitorization of arterial pressure but also of the parameters of gaseous interchanges necessary in these patients.

Adult↗