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Biomedical subjects

M Leblanc

Publications and source records attributed to M Leblanc.

At least 73 records · Page 4Linked to original sources
PubMed1995

Bicarbonate dialysate for continuous renal replacement therapy in intensive care unit patients with acute renal failure.

Lactate-buffered peritoneal solution traditionally has been used as dialysate for continuous renal replacement therapy (CRRT) in the United States because no bicarbonate solution is commercially available. Since 1994, the Cleveland Clinic Foundation Dialysis Unit has prepared a bicarbonate solution (sodium 144 +/- 3 mEq/L, HCO3 37 +/- 2 mEq/L, potassium 3 or 4 mEq/L, calcium 3.0 +/- 0.3 mEq/L, and magnesium 1.4 +/- 0.3 mg/dL) replicating the dialysate for chronic intermittent hemodialysis. No solute precipitation, as calcium or magnesium salts, were observed, and several cultures of the solution, performed at various time periods, remained negative. Fifty critically ill acute renal failure patients have been treated with bicarbonate-CRRT. All patients were in multiple organ failure and required mechanical ventilation; 37 were receiving vasopressors. Forty-four continuous venovenous hemodialysis sessions and eight continuous arteriovenous hemodialysis sessions were performed with a mean duration of 7.8 +/- 6.1 days. The mean inflow dialysate rate was 1,249 +/- 225 mL/hr and the mean outflow rate (dialysate plus ultrafiltration) was 1,399 +/- 237 mL/hr; the inflow rate was constantly kept lower or equal to the outflow rate to avoid an enhanced potential for backfiltration. No related fever spikes or sepsis episodes were noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1995

Methodological issues in assessing reproducibility--a comparative study of various indices of reproducibility applied to repeat ELISA serologic tests for Lyme disease.

This study applies and evaluates a variety of different measures of reproducibility. As an example, repeat enzyme-linked immunosorbent assays (ELISA) for antibodies to Borrelia burgdorferi, the etiologic agent of Lyme disease, are used. These repeat tests were part of the 1991 Quality Control Assessment of provincial laboratories that was carried out by the Laboratory Centre for Disease Control (Ottawa). Twenty-seven sera from cases and non-cases were tested by three laboratories, and two laboratories repeated the tests once. Methodological issues discussed include: different methods of assessing reproducibility in the continuous scale; whether reproducibility should be assessed with data in continuous or categorical form; problems assessing the reproducibility of data that has been standardized using a calibration-regression line; and problems with external generalizability of reproducibility studies of rare diseases. The authors conclude that the statistical method used to assess the reproducibility of a test must be adjusted to suit individual study designs and data, and the usage of the test.

Antibodies, Bacterial↗
PubMed1995

Reproducibility and validity of a food-frequency questionnaire designed for use in girls age 7 to 12 years.

This study focused on a food-frequency questionnaire (FFQ) designed to measure nutrient intake in girls aged 7 to 12 years, inclusive. The instrument's reproducibility and validity were assessed using food records (FRs) as gold standards of measurement. Log-transformed nutrient intake estimates were compared from two FFQs and between FFQs and FRs. Intraclass correlation coefficients measuring the reproducibility of the FFQ ranged from 0.11 (starch) to 0.69 (fiber). Intraclass correlation coefficients measuring agreement between FFQ and 14l-day FR data varied between 0.15 (starch) and 0.68 (vitamin B2) for the first, and between 0.06 (starch) and 0.95 (vitamin B1) for the second FFQ. FFQs were in the best agreement with FRs for the following nutrients: fiber, vitamin B1, vitamin B2, vitamin C, and beta-carotene. Joint classifications revealed that overall, 36% of subjects were similarly categorized by FFQ and FR, and 70% of those in the lowest or highest FR quartiles were were found in the lowest or highest FR quartiles were found in the lowest or highest two FFQ quartiles, respectively.

Ascorbic Acid↗
PubMed1995

What dialysis dose should be provided in acute renal failure? A review.

Increased dialysis dose has been shown to improve morbidity and survival in chronic hemodialysis patients. Despite improvement in care and technological aspects of renal replacement therapy, mortality rates of acute renal failure (ARF) have remained essentially unchanged for over two decades, exceeding 50% in most studies. The occurrence of ARF in older patients with more complicated medical and surgical conditions has contributed to this lack of outcome amelioration, and death of ARF patients is now more frequently caused by underlying disease than ARF itself. A recent prospective survey at this institution found a mortality rate of 79.1% among a total of 363 ARF medical and surgical intensive care unit patients, with a mean age near 60 years and a mean admission APACHE II score of over 20, who were treated by intermittent hemodialysis and continuous renal replacement therapy (CRRT). Nonsurvivors had a mean of over four failed systems, in addition to the renal failure, compared with survivors who had less than four. The standards for dialysis adequacy in ARF are not currently defined. Increased catabolism seen in ARF patients in the intensive care unit may justify large dialysis dose delivery. An apparent influence of delivered dialysis dose on the outcome of ARF intensive care unit patients has been recently observed at our institution. Compared with nonsurvivors, survivors had received significantly higher dialysis dose, as assessed by Kt/V and urea reduction ratio. In ARF patients, the discrepancy between delivered versus prescribed dialysis dose may be particularly important and contributed to by the following: reduced blood flow rate and dialysis time consequent to patient intolerance; lower dialyzer in vivo clearances, particularly in heparin-free dialysis; blood recirculation when using temporary vascular access; and postdialysis urea rebound. Prolonging the course of renal failure is one of the risks attributed to frequent dialysis; hypotension and ultrafiltration combined with a deficient renal autoregulation can result in further renal damage. The detrimental effects of bioincompatible membranes have been demonstrated with an induced-delay of renal function recovery. A recent study has reported benefits of biocompatible membranes in terms of potential for renal recovery and maintenance of urine output during dialytic support when compared with bioincompatible membranes. CRRT offers many advantages over intermittent hemodialysis for ARF intensive care unit patients: better hemodynamic tolerance, avoidance of solute rebound, and removal of serum sepsis mediators. However, CRRT have not yet been firmly shown to improve survival rates. Recently, urea kinetics have been used to estimate dialysis dose provided by CRRT.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Kidney Injury↗
PubMed1995

Quantitative measures of human immunodeficiency virus-specific antibodies predict progression to AIDS.

Studies examining specific antibodies directed against antigenic components of human immunodeficiency virus (HIV), as potential markers of progression to AIDS, have reported inconsistent results. We used reflectance densitometry and survival analysis to determine whether single quantitative measures of HIV-specific antibodies predicted progression to AIDS in a prospective cohort of 159 HIV-infected homosexual men. Lowered baseline levels of p24 antibody and p24/gp41 antibody ratio were independent predictors of progression to AIDS and retained statistical significance after simultaneously controlling for CD4:CD8 ratio, age, use of zidovudine, and clinical symptoms. Quantitative measures of p24 antibody and p24/gp41 antibody ratio warrant further study with regards to their clinical application as markers of HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Is body powered operation of upper limb prostheses feasible for young limb deficient children?

The investigators measured efficiencies of body powered prehensors and cable control components of prostheses available for young children. Results indicated that the cable control systems and hook type prehensors have moderate to high efficiencies, but children's body powered hands have very low efficiencies. Measures of arm and shoulder strength of 3-5 year-old limb deficient children, both on the limb deficient and sound sides, were less than that reported in the sound sides, were less than that reported in the literature for normal children. The findings were examined in relation to children's strength available compared with prosthesis strength requirements. The comparison demonstrates a way to establish measurable efficiency targets for new prehensor designs. The article includes detailed findings on children's strength, and findings on efficiencies of the prehensors and cable control systems of children's upper limb prosthses. Sample calculations may be useful to future designers of body powered prehensors for young children. A more efficient body powered hand is especially needed. Preliminary calculations indicate that the use of currently available children's voluntary opening (VO), body powered hands is not feasible, given the low strength of young limb deficient children and the low efficiencies of the VO hands. The use of voluntary closing (VC) hands may be feasible but remains to be tested.

Age Factors↗
PubMed1995

[Parvovirus B19 infection and pregnancy].

Parvovirus B19 was identified in 1975. It causes infections megalerythemia in adults associated with skin eruptions and joint pain (about 50% of the adult population is immunized). The risk of contamination in case of an epidemia is high in school teachers and school personnel. In 1984, the parvovirus B19 was implicated as the cause of fetal anasarca. The risk of transplacental contamination is estimated at 33% in case of maternal infection. Pregnant women with parvovirus B19 infection and confirmed serology should have an echography every 15 days. Fetal anasarca can be complicated by in utero fetal death related to erythroid stem-cell anaemia. The diagnosis of fetal infection is based on PCR techniques on fetal blood. Symptomatic antenatal treatment with in utero transfusion was proposed as early as 1988. This method does not however appear to be necessary in all cases as the outcome in several reports of untreated fetuses was delivery of a normal child. There is the possibility of myocardial damage caused by parvovirus B19 which would make in utero transfusion difficult and limit its beneficial effect. Finally associated thrombopenia is often severe and increased fetal risk.

Erythema Infectiosum↗
PubMed1995

Determinants of late allograft nephrectomy.

When loss of graft function occurs more than six months after transplantation, allograft nephrectomy is not routinely performed at the time of graft failure. It is usually performed only on those patients who subsequently develop specific complications. However, little is known about the characteristics that make patients more likely to require allograft nephrectomy. The purpose of our study was to identify risk factors for the subsequent need for allograft nephrectomy in patients with graft failure occurring more than 6 months after transplantation. Forty-one patients were studied. Inclusion criteria were: loss of graft function > or = 6 months after transplantation, resumption of dialysis and initiation of weaning from immunosuppression. Thirty patients were treated with cyclosporine + prednisone +/- azathioprine and 11 with azathioprine + prednisone. Mean follow-up time was 17.8 months, ranging from 6 months to 6.1 years. Recipient age, sex and race, original renal disease, donor, donor source (cadaveric vs living related), HLA compatibility, levels of panel reactive antibodies, occurrence of initial delayed graft function, causes of graft failure and tapering of immunosuppression were similar in patients with and without allograft nephrectomy. Using univariate analysis, allograft nephrectomy was found to be significantly more frequent in patients with a history of 2 or more episodes of acute rejection than in patients with no rejection episode: 83% vs 30% (p = 0.03). In addition, allograft nephrectomy was found to be significantly more frequent if the immunosuppressive regimen included cyclosporine (62% vs 27.3%; p = 0.04). Using multivariate analysis however, the number of previous episodes of rejection was found to be the only significant predictor for allograft nephrectomy. None of the other variables considered in the multivariate analysis, including the type of immunosuppressive therapy, was identified as a significant predictor for the need to perform allograft nephrectomy. In summary, the need for late allograft nephrectomy was correlated with the number of previous episodes of acute rejection. Patients with a history of numerous rejection episodes should thus be considered more likely to require allograft nephrectomy once immunosuppression is withdrawn. Possible interventions to reduce or prevent the need for nephrectomy include more gradual tapering of immunosuppression at the time of graft failure or indefinite low-dose immunosuppressive therapy.

Adult↗
PubMed1994

High dialysate flow rate continuous arteriovenous hemodialysis: a new approach for the treatment of acute renal failure and tumor lysis syndrome.

A continuous dialysis technique such as continuous arteriovenous hemodialysis (CAVHD) could be an interesting alternative to frequent intermittent hemodialysis to treat acute renal failure (ARF) secondary to tumor lysis syndrome (TLS). However, because of massive release of intracellular solutes in TLS, CAVHD clearances need to be increased to treat this syndrome. Continuous arteriovenous hemodialysis using a high dialysate flow rate at 4 L/hr was assessed in TLS and ARF associated with severe hyperphosphatemia. A 0.6-m2 hollow-fiber polyacrylonitrile dialyzer (Multiflow 60; Hospal, St-Léonard, Québec, Canada) was used. Blood urea nitrogen and serum creatinine levels decreased, respectively, from 102.5 to 27.2 mg/dL and from 3.1 to 1.8 mg/dL during the 36 hours of treatment. Serum urate concentration was normal at the beginning of treatment (4.5 mg/dL) and decreased to 2.1 mg/dL by the end of CAVHD. Serum phosphorus decreased from 16.7 to 4.4 mg/dL after the 36 hours of treatment. The calcium x phosphorus product decreased from 111.1 to 42.1 by 28 hours and remained under 50 thereafter. Serum potassium was easily controlled with the addition of 2.5 mEq/L of KCl in dialysate and replacement solutions. No rebound increases in phosphorus or potassium were noted after cessation of therapy. Continuous arteriovenous hemodialysis clearances of urea, creatinine, phosphorus, and urate were measured at 2-hour intervals for the first 24 hours and at 4-hour intervals for the remaining 12 hours. They were 53.0 +/- 2.3 mL/min, 43.7 +/- 2.2 mL/min, 40.4 +/- 1.9 mL/min, and 39.3 +/- 1.9 mL/min (n = 15), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1994

Severe skin necrosis associated with heparin in hemodialysis.

Skin necrosis is a well-recognized although rare complication of continuous heparin therapy. We report the case of a 66-year-old diabetic woman with end-stage renal failure who received intermittent intravenous heparin during hemodialysis. She developed severe necrotic cutaneous ulcers over both legs, with typical histological findings. Thrombocytopenia never occurred but platelet studies demonstrated enhanced aggregation when heparin was added in vitro. Platelet-aggregating immunoglobulins produced in response to heparin can lead to thrombotic events. Thrombocytopenia usually develops prior to the onset of cutaneous lesions, but as in this case, may be absent. Heparin should be discontinued when the condition is recognized. Unfortunately, a poor outcome is frequently observed.

Aged↗
PubMed1992

Early disruptive behavior, poor school achievement, delinquent behavior, and delinquent personality: longitudinal analyses.

Three alternative models concerning the causal links between early disruptive behavior, poor school achievement, and delinquent behavior or antisocial personality were tested with linear structural equation modeling. Subjects were boys and girls followed from first grade to age 14. Disruptive behavior was assessed in Grade 1; school achievement was assessed in Grades 1 and 4; delinquent behavior and antisocial personality were assessed at age 14. With regard to self-reported delinquent behavior at age 14, results indicate that the best model for boys was a direct causal link between Grade 1 disruptive behavior and delinquent behavior. Poor school achievement was not a necessary causal factor. For girls, none of the tested models were a good fit to the delinquent behavior data. As for delinquent personality, results indicate that, for both boys and girls, poor school achievement was a necessary component of the causal path between Grade 1 disruptive behavior and age 14 delinquent personality.

Achievement↗
PubMed1992

Behavioural and cognitive characteristics of conduct disordered-hyperactive boys from age 6 to 11: a multiple informant perspective.

Three subgroups of kindergarten boys (stable conduct disordered-hyperactive (SCDH), stable conduct disordered (SCD), stable non-deviant control (SC)) were defined and followed up three, four and five years later in primary school. Using assessments from multiple informants (teachers, mothers, peers, self), the results showed that SCDH boys were more hyperactive (i.e. overactive/inattentive) and displayed a greater diversity of conduct problems in school and home at follow-up compared to the other groups. These results and the fact that during early adolescence SCDH boys tend to develop a worse prognosis than SCD boys suggest that they should be distinguished.

Antisocial Personality Disorder↗