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Biomedical subjects

J A Herrero

Publications and source records attributed to J A Herrero.

At least 19 recordsLinked to original sources
PubMed2006

Electromyostimulation and plyometric training effects on jumping and sprint time.

This study compared the effects of four-week training periods of electromyostimulation (EMS), plyometric training (P), or combined EMS and P training of the knee extensor muscles on 20 m sprint time (ST), jumping ability (Squat jump [SJ] and Countermovement jump [CMJ]), maximal isometric strength (MVC), and muscle cross-sectional area (CSA). Forty subjects were randomly assigned to one of the four treatment groups: electromyostimulation (EG), plyometric (PG), combined EMG, and P (EPG), that took place 4 times per week, and a control group (CG). Subjects were tested before and after the training program, as well as once more after 2 wk of detraining. A significant improvement (p < 0.05) in ST was observed after training (2.4 %) in EG while a significant slowing (p < 0.05) was observed (- 2.3 %) in EPG. Significant increases in EPG (p < 0.05) were observed in SJ (7.5 %) and CMJ (7.3 %) after training, while no significant changes in both jumps were observed after training and detraining for EG. A significant increase (p < 0.05) in MVC was observed after training (9.1 %) and after detraining (8.1 %) in EG. A significant increase (p < 0.05) in MVC was observed after training (16.3 %) in EPG. A significant increase (p < 0.01) in CSA was observed after training in EG (9.0 %) and in EPG (7.1 %). EMS combined with plyometric training increased the jumping height and sprint run in physically active men. In addition, EMS alone or EMS combined with plyometric training leads to increase maximal strength and to some hypertrophy of trained muscles. However, EMS training alone did not result in any improvement in jumping explosive strength development or even interfered in sprint run.

Adult↗
PubMed2005

The validation of a new method that measures contact and flight times during vertical jump.

The aim of this study was to design and validate a vertical jump assessing system based on flight time measurements. Hence, the first phase of this study consisted of programming the software SportJumpv-1.0 and adapting a contact mat and a computer mouse in order to record the flight and contact times of a jump test. In the second phase, 9 subjects made 12 maximal and submaximal vertical single and rebound jumps. Thus 108 flight times and 36 contact times were simultaneously obtained with five different systems: ErgoJump Bosco System (PS), SportJump-v1.0 (SJ), Force Plate (FP), High-speed camera (HSC), and a Led (LED) filmed with a high-speed camera; FP was considered as the reference system. No significant differences were found either between SJ and LED, or between FP and HSC systems. SJ and LED overestimate flight time (9 ms and p < 0.001) and underestimate contact time in respect to FP values. PS underestimates flight time regarding FP values (4 ms and p < 0.01). In spite of the differences obtained between the systems, the errors found are constant. Those slightly depend on the subject's body mass for the systems that are connected to a contact mat. A high correlation between all of them was obtained (r approximately 1 and p < 0.001). The SJ system was validated for an accuracy of 500 Hz, and it was shown to be a useful tool in measuring flight and contact times during jumping. The differences and correlations found between the five systems show that it is necessary to take into account which system is being used when analyzing vertical jump performance.

Adolescent↗
PubMed2005

[Vascular access guidelines for hemodialysis].

Quality of vascular access (VA) has a remarkable influence in hemodialysis patients outcomes. Dysfunction of VA represents a capital cause of morbi-mortality of these patients as well an increase in economical. Spanish Society of Neprhology, aware of the problem, has decided to carry out a revision of the issue with the aim of providing help in comprehensión and treatment related with VA problems, and achieving an homogenization of practices in three mayor aspects: to increase arteriovenous fistula utilization as first vascular access, to increment vascular access monitoring practice and rationalise central catheters use. We present a consensus document elaborated by a multidisciplinar group composed by nephrologists, vascular surgeons, interventional radiologysts, infectious diseases specialists and nephrological nurses. Along six chapters that cover patient education, creation of VA, care, monitoring, complications and central catheters, we present the state of the art and propose guidelines for the best practice, according different evidence based degrees, with the intention to provide help at the professionals in order to make aproppiate decissions. Several quality standars are also included.

Arteriovenous Shunt, Surgical↗
PubMed2002

Pulmonary diffusing capacity in chronic dialysis patients.

Patients with end-stage renal disease treated by hemodialysis with bioincompatible membranes are exposed during the dialysis period to acute effects on lung microcirculation, which may result in pulmonary fibrosis and diffusion defects in long-standing dialysis. To investigate the occurrence of these possible chronic pulmonary alterations, we determined lung function in patients with chronic renal failure not undergoing hemodialysis and in patients who had been receiving regular hemodialysis both for short and long periods of time. Forty-three patients divided into three groups were studied: 17 patients before dialysis with a mean (SD) creatinine clearance of 14.1 (6.8) ml/min 11.73 m2, 10 patients receiving regular hemodialysis for a period of less than 12 months (mean 6.4 +/- 3.5 months), and 16 patients receiving regular hemodialysis for more than 5 years (mean 8.3 +/- 3.6 years). First-use bioincompatible cellulosic dialysis membranes were used in all the cases. The following parameters were recorded: forced vital capacity (FVC), forced expiratory volume in 1s (FEV1), total lung capacity (TLC), residual volume (RV), carbon monoxide transfer factor (TLCO), accessible lung volume (VA), carbon monoxide transfer factor/accessible lung volume (KCO- that is, TLCO/VA), and arterial blood gases. Patients receiving regular hemodialysis for more than 5 years showed significantly lower values of TLCO and KCO than patients before dialysis and patients receiving regular hemodialysis for less than 12 months. Seventy-five percent of patients on long-term hemodialysis had markedly reduced TLCO or KCO values (below 80% of the reference value) as compared with 17% of patients before dialysis and 10% of patients dialyzed for less than 12 months (P < 0.001). Differences among groups for the remaining parameters were not observed. In conclusion, patients undergoing long-term regular hemodialysis with a bioincompatible membrane showed a selective reduction in pulmonary diffusing capacity possibly due to chronic pulmonary fibrosis.

Aged↗
PubMed2001

Incidence of renal artery stenosis in pediatric en bloc and adult single kidney transplants.

BACKGROUND: The incidence, time of onset, and outcome of transplant renal artery stenosis (TRAS) in pediatric en bloc (PT) and adult single-kidney (AT) transplants were reviewed. METHODS: Forty-three cases (7 PT and 36 AT) of suspected TRAS were selected out of 367 functioning grafts (35 of them PT). Diagnosis was performed by digital subtraction arteriography. Percutaneous transluminal angioplasty (PTA) was performed when needed. RESULTS: Seven (20%) PT and 24 (7.1%) AT presented TRAS. Time of onset was 7+/-1 months in PT and 18+/-17 months in AT (P<0.05). PTA was performed in all cases of TRAS in PT and in 19 AT. One PT and 7 AT had re-stenosis. There was no significant difference in renal function after treatment. Control of blood pressure improved in both groups. CONCLUSIONS: Recipients of PT grafts showed a higher incidence and earlier onset of TRAS. Re-stenosis was more frequent in AT.

Adolescent↗
PubMed2001

Long-term experience with the Thomas shunt, the forgotten permanent vascular access for haemodialysis.

BACKGROUND: Vascular access complications are the main cause of hospitalization in dialysis patients. The difficulty in creating and maintaining vascular access after several years on haemodialysis (HD) remains the primary problem in these patients. The femoro-femoral Thomas shunt is a permanent vascular access that was used in the 1970s and is all but forgotten at present. We analysed our experience with the Thomas shunt since 1979 in patients with no other possibility of regular vascular access. METHODS: We retrospectively studied 27 Thomas shunts implanted in 10 patients, aged 27-75 years at the time of first shunt implantation. Prior to implantation of the Thomas shunt, these patients had experienced 80 failed vascular accesses (plus four patients on CAPD), with an average of 8.6 accesses per patient. All Thomas shunts were implanted in femoral vessels. Clinical data were extracted from hospital and dialysis unit records and were analysed for efficacy, complications, and duration of patency. RESULTS: Total follow-up was 1176 months, with an average shunt duration of 43.7 months (range 3-151 months). One-, 2-, 3- and 6-year survival rates were 85, 57, 49 and 25% respectively. Five patients spent more than 10 years on HD using the Thomas shunt, and one patient had the same unit for 12.5 years. A high blood flow (450 ml/min) was obtained, without recirculation, due to the characteristics of this shunt. Efficacy, measured as percentage urea reduction (PRU), was high (on average 77.8+/-1.5%). The infection incidence was one episode every 37.5 patient-months, Staphylococcus species being the most commonly isolated. There were no shunt removals because of infection. The most important cause of shunt withdrawal was thrombosis, with an incidence of one episode every 7 patient-months. Percutaneous angioplasty was successful in the majority of stenosis episodes. CONCLUSIONS: This study indicates that the Thomas shunt provides a good permanent vascular access for HD patients who have no other possibility of a regular vascular access. This shunt offers high dialysis efficacy without recirculation and an access duration comparable to AV fistulae. For these reasons the Thomas shunt should continue to be used as a vascular access in HD.

Adult↗
PubMed1998

[Invasive fungal infections in liver transplant recipients: analysis of 21 cases].

BACKGROUND: Invasive fungal infections (IFI) are one of the most important causes of mortality in liver transplant (LT) recipients. The aim of this study was to describe the characteristics of IFI in the LT program of our institution with an special emphasis in the differences between Candida infections (CI) and that caused by other fungi (NCI). PATIENTS AND METHODS: Retrospective analysis of the hospital charts of 21 patients who underwent a LT from February 1987 to December 1995. The diagnosis of IFI required the histological evidence of tissue invasion or a positive culture in a tissue sample or in an usually sterile fluid. Esophageal candidiasis was not considered as IFI. Antifungal prophylaxis was performed either with nystatin or fluconazole. RESULTS: Twenty-one of 356 patients (6%) developed a total of 23 episodes of IFI. Pathogens were Candida spp. (n = 10), Aspergillus (n = 8), Zygomicetes (n = 4) and Cryptococcus (n = 1). Fifty-seven percent of the episodes of IFI (80% of those caused by Candida and 38% of those produced by other fungi; p < 0.05) developed in the first 3 months after transplantation and only 5 episodes appeared after the sixth month. The diagnosis of IFI was done at autopsy in 6 patients (29%). Overall, NCI (13 episodes) predominated over CI (10 episodes), being the later the cause of the 54% of the episodes in the first 178 recipients but only the 30% in the last 178 patients (p = 0.09). No differences were found in the distribution of the risk factors amongst those patients with CI or NCI. Seventeen of the 21 patients (71%) died and 15 of these deaths (72%) were attributable to fungi; 15 patients who died either did not receive amphotericin (n = 6) or received a cumulative dose lower than 500 mg. Six patients received a cumulative dose of more than 1.5 g (mean, 3.2 g) and four of them were cured. Mortality in the nonfungal infection group was 26% (p < 0.001). CONCLUSIONS: IFI was a rare but severe complication in our LT recipients. The relative frequency of CI was progressively decreasing during the study period, being NCI the predominant infections. Amphotericin therapy was effective only when a high cumulative dose could be administered.

Adult↗
PubMed1998

Functional glomerular reserve in recipients of en bloc pediatric transplant kidneys.

BACKGROUND: The transplantation of an adequate renal mass is increasingly recognized to be of importance. The improved graft survival is probably due to a lesser risk of developing hyperfiltration-associated lesions. METHODS: We have reviewed the glomerular reserve in our recipients of en bloc pediatric transplant kidneys after an intravenous amino acid overload and compared them to single adult kidney transplant recipients. RESULTS: En bloc transplants evidenced increased glomerular filtration rate as compared with baseline as from the second hour of amino acid infusion (from 71+/-14 to 84.9+/-17 ml/min, 1.73 m2, P<0.05) and increased renal plasma flow as from the third hour (from 335+/-116 to 402+/-155 ml/min, 1.73 m2, P<0.05). In the single adult kidney recipient group, no change was seen either in the glomerular filtration rate (from 62.5+/-13 to 58.1+/-13 ml/min, 1.73 m2, P=NS) nor in renal plasma flow (from 354+/-125 to 304+/-98 ml/min, 1.73 m2, P=NS). CONCLUSIONS: These results show that patients receiving en bloc pediatric kidney transplantations have a greater renal functional reserve and show a lesser risk of hyperfiltration.

Adult↗
PubMed1997

Clinical presentation and outcome of tuberculosis in kidney, liver, and heart transplant recipients in Spain. Spanish Transplantation Infection Study Group, GESITRA.

BACKGROUND: Tuberculosis is unusual in transplant recipients. The incidence, clinical manifestations, and optimal treatment of this disease in this population has not been adequately defined. The present study was undertaken to assess the incidence, clinical features, and response to therapy of Mycobacterium tuberculosis infection in solid-organ transplant recipients. METHODS: We evaluated retrospectively the incidence, clinical characteristics, diagnostic procedures, antituberculous treatment, clinical course, and factors influencing mortality in 51 solid-organ transplant recipients who developed tuberculosis after transplantation. We also reviewed the world literature on tuberculosis in solid-organ transplantation. RESULTS: The overall incidence of tuberculosis was 0.8%. The localization was pulmonary in 63% of the cases, disseminated in 25%, and extrapulmonary in 12%. Tuberculosis developed from 15 days to 13 years after surgery (mean, 23 months). In one third of the cases, diagnosis was not suspected initially, and in three cases, diagnosis was made at necropsy. Fever was the most frequent symptom, followed by constitutional symptoms, cough, respiratory insufficiency, and pleuritic pain. Fifteen patients (33%) developed hepatotoxicity during treatment; hepatotoxicity was severe in seven cases. Hepatotoxicity was higher in patients receiving four or more antituberculous drugs (50%) than in patients receiving three drugs (21%; P=0.03). Serum levels of cyclosporine decreased in the 26 patients under the simultaneous use of rifampin. Nine of them (35%) developed acute rejection, and five (56%) died, in comparison with 3 of 17 patients (18%) who did not develop rejection after the use of cyclosporine and rifampin (P=0.03). Although microbiological response was favorable in 94% of the 35 patients who completed 6 or more months of treatment, 16 other patients (31%) died before diagnosis or in the course of treatment. None of the patients treated for more than 9 months died as a consequence of tuberculosis, whereas the mortality rate was 33% among those treated for 6 to 9 months (P=0.03). Use of antilymphocyte antibodies or high doses of steroids for acute rejection before tuberculosis was associated with a higher mortality rate. CONCLUSIONS: M tuberculosis causes serious and potentially life-threatening disease in solid-organ transplant recipients. Treatment with at least three drugs during 9 months or more, avoiding the use of rifampin, appears to be appropriate.

Adult↗
PubMed1997

Cardiovascular effects of recombinant human erythropoietin in predialysis patients.

Treatment with recombinant human erythropoietin (rHuEPO) has solved the problem of anemia in patients on dialysis. However, its application to predialysis patients has raised some doubts about its effects on the progression of renal disease and on blood pressure (BP) and hemodynamic regulation. We have prospectively studied over at least 6 months a group of 11 predialysis patients receiving rHuEPO treatment (initial dose, 1,000 U subcutaneously three times a week). Clinical assessment and biochemical and hematologic measurements were made once every 2 weeks. Twenty-four-hour ambulatory BP monitoring, echocardiography, and determination of neurohumoral mediators of hemodynamics were performed once every 3 months. An adequate hematologic response was found (hemoglobin, 11.7 +/- 0.4 g/dL v 9 +/- 0.3 g/dL) without changes in the progression of renal disease. A decrease in cardiac output and an increase in total peripheral resistance was seen as anemia improved. A trend toward decreased left ventricular (LV) thickness and a significant decrease in LV mass index (from 178.2 +/- 20.6 g/m2 to 147.3 +/- 20.6 g/m2) were observed. Blood pressure control did not improve; moreover, in some patients an increase in systolic values was detected by ambulatory BP. Casual BP remained seemingly stable. Sequential determinations of neurohumoral mediators of hemodynamic substances (endothelin, renin, norepinephrine, epinephrine, dopamine) failed to explain these results. Ambulatory BP reveals a worse control in some patients who were previously hypertensive and confirms the utility of this technique in the assessment of patients under erythropoietin treatment. The trend toward LV hypertrophy regression without improved BP control confirms the role of anemia among the multiple factors leading to LV hypertrophy in end-stage renal disease (ESRD), and opens therapeutic possibilities. Better control of BP may avoid a potential offsetting of beneficial effects that correcting anemia would have on the cardiovascular system.

Adult↗
PubMed1997

Calcium salts of keto-amino acids, a phosphate binder alternative for patients on CAPD.

Control of hyperphosphoremia is crucial to the prevention of secondary hyperparathyroidism. Calcium salts of keto-amino acids (KAA) were employed as phosphate binders in hemodialysis patients. We wanted to assess the efficacy of these substances as quelating agents in patients under continuous ambulatory peritoneal dialysis (CAPD). Also, as an amino acid supplement, we determined their possible effect on some parameters related to nutritional status. We studied 13 patients (7 M; 6 F) with a mean age of 45.2 +/- 17 years and a mean time on CAPD of 18.4 +/- 11.4 months. None had severe secondary hyperparathyroidism and/or clinically relevant aluminium intoxication. They were not receiving calcitriol and none were using low-calcium peritoneal dialysis fluids. All were under aluminum hydroxide (AlOH3) treatment and 8 patients also received calcium carbonate. These quelating agents were withdrawn and after 21 days (wash-out period) KAA were initiated. We analyzed serum levels of bone metabolism parameters (calcium, phosphate, osteocalcin [OC], intact parathyroid hormone [iPTH], alkaline phosphatase [AP]) and nutritional parameters (total protein, albumin, pre-albumin, transferrin) in four periods: (A) during AlOH3; (B) immediately after the washout period; (C) after 1.5 months; and (D) after 3 months of KAA therapy. In 5 patients serum aluminum level was also measured in periods (A) and (D). The serum phosphate level at period (B) was significantly higher than in other periods. After 3 months of treatment phosphate levels decreased significantly (A = 1.77 +/- 0.3 mmol/l vs D = 1.48 +/- 0.2; p < 0.05). Serum calcium levels increased, while iPTH and OC decreased (p = ns). AP remained stable during the study. All nutritional parameters increased at the end of the study (p = ns). Calcium salts of keto-amino acids showed to be an effective alternative to aluminum-containing phosphate binders. They were well tolerated, without relevant side-effects. These compounds could also represent an additional source of oral amino acid supplementation with improvement of nutritional status.

Administration, Oral↗
PubMed1996

Double renal transplant from infant donors. A good alternative for adult recipients.

Several groups have reported technical complications and poor graft survival rates in kidney transplants from pediatric donors to adult recipients. Increased incidences of acute rejections, vascular thrombosis, and early glomerulosclerotic lesions have led many groups to abandon this graft combination. Over the last 4 years, we have set up a program of two-kidney transplantation from cadaveric infant donors under age 3 years, which to date includes 15 adult recipients. Thirteen of these grafts are currently functioning at least as well as those from adult donors, after a mean follow-up of 1.5 years. Our surgical and therapeutic procedures have led to a minimization of the early complications reported by other groups. With this transplantation procedure, the patients receive double the number of nephrons, which will probably give them better long-term function. The encouraging results achieved by our group may help change the current consideration of pediatric donors as "suboptimal" ones.

Adolescent↗