Search PubMed⌕ Search

Biomedical subjects

S Mir

Publications and source records attributed to S Mir.

At least 19 recordsLinked to original sources
PubMed2004

Revisiting the accuracy of peak flow meters: a double-blind study using formal methods of agreement.

BACKGROUND: There is widespread use of peak flow meters in both hospitals and general practice. Previous studies to assess peak flow meter accuracy have shown significant differences in the values obtained from different meters. However, many of these studies did not use human subjects for peak flow measurements and did not compare meters of varying usage. In this study human subjects have been used with meters of varying usage. METHODS: Participants were tested using two new (meters A and C) and one old peak flow meter (meter B) in random order. The study was double-blinded. Participants were recruited from the university campus. RESULTS: Four hundred and nine individuals participated. The difference between peak flow means of A and B was -9.93 l/min (95% CI: -12.37 to -7.48, P<0.0001). The difference between peak flow means of B and C was 20.08 l/min (95% CI: 17.85-22.29, P<0.0001). The difference between peak flow means of A and C was 10.15 l/min (95% CI: 7.68-12.61, P<0.0001). CONCLUSION: There was a significant difference between the values obtained from the new and old peak flow meters and also between the two new peak flow meters. We conclude that there is need for caution in interchangeably using flow meters in clinical practice.

Adult↗
PubMed2002

Novel ATP6V1B1 and ATP6V0A4 mutations in autosomal recessive distal renal tubular acidosis with new evidence for hearing loss.

Autosomal recessive distal renal tubular acidosis (rdRTA) is characterised by severe hyperchloraemic metabolic acidosis in childhood, hypokalaemia, decreased urinary calcium solubility, and impaired bone physiology and growth. Two types of rdRTA have been differentiated by the presence or absence of sensorineural hearing loss, but appear otherwise clinically similar. Recently, we identified mutations in genes encoding two different subunits of the renal alpha-intercalated cell's apical H(+)-ATPase that cause rdRTA. Defects in the B1 subunit gene ATP6V1B1, and the a4 subunit gene ATP6V0A4, cause rdRTA with deafness and with preserved hearing, respectively. We have investigated 26 new rdRTA kindreds, of which 23 are consanguineous. Linkage analysis of seven novel SNPs and five polymorphic markers in, and tightly linked to, ATP6V1B1 and ATP6V0A4 suggested that four families do not link to either locus, providing strong evidence for additional genetic heterogeneity. In ATP6V1B1, one novel and five previously reported mutations were found in 10 kindreds. In 12 ATP6V0A4 kindreds, seven of 10 mutations were novel. A further nine novel ATP6V0A4 mutations were found in "sporadic" cases. The previously reported association between ATP6V1B1 defects and severe hearing loss in childhood was maintained. However, several patients with ATP6V0A4 mutations have developed hearing loss, usually in young adulthood. We show here that ATP6V0A4 is expressed within the human inner ear. These findings provide further evidence for genetic heterogeneity in rdRTA, extend the spectrum of disease causing mutations in ATP6V1B1 and ATP6V0A4, and show ATP6V0A4 expression within the cochlea for the first time.

Acidosis, Renal Tubular↗
PubMed2001

Inferior vena cava indices determine volume load in minimal lesion nephrotic syndrome.

The pathogenesis of edema in nephrotic syndrome has not been entirely understood. We investigated the value of the echographic parameters [inferior vena cava index (IVCI), inferior vena cava collapsibility index (IVCCI), and left atrium diameter (LAD)] to determine the volume load in children with minimal lesion nephrotic syndrome (MLNS). Twelve children with MLNS (seven boys, five girls) were included in this study. The patients were classified into three different stages (stage A: edematous; stage B: 50% decrease in weight gain; stage C: edema free) following measurement of their ideal weights. The ideal weight of patients in stage A was increased 13 +/- 7%. Serum total protein, albumin and urine sodium levels were found to be low in these patients. Plasma renin activity (PRA) and serum aldosterone levels in stage A were significantly different from those of the control group (P<0.05). PRA and serum aldosterone levels were not different from those of the control group in stage B (P>0.05). However, the increase in PRA was significant in stage C. Although a significant weight decrease was found in stages B and C, it had no effect on IVCI, LAD, and cardiothoracic index. We consider IVCI, IVCCI, and LAD measurements by echocardiography (ECHO) to be easy and reliable clinical methods for assessing the intravascular volume load in patients with MLNS.

Adult↗
PubMed2001

Hemodiafiltration for vancomycin overdose in a patient with end-stage renal failure.

A 17-year-old anuric female patient with end-stage renal failure received a massive overdose of vancomycin and was treated with high-flux hemodiafiltration, as described in this report. The hemodiafiltration procedure with a polysulfone membrane was performed 3 times. The vancomycin concentration was decreased from 101 mg/l to 16.59 mg/l at the end of the procedure. No adverse effects were noted from either vancomycin or hemodiafiltration. Hemodiafiltration with a high-flux polysulfone membrane is a novel and safe treatment modality for vancomycin overdose in pediatric patients.

Adolescent↗
PubMed2001

Atypical antipsychotics and hyperglycaemia.

Hyperglycaemia is known occasionally to occur with conventional neuroleptics, but has more recently been associated with atypical antipsychotics especially clozapine and olanzapine. This article examines more closely this association. A review of relevant published literature from 1970 to date was undertaken following Medline and Embase searches in June 2000. Hyperglycaemia with clozapine was widely reported: spontaneous reports of either hyperglycaemia or ketoacidosis were described in a total of 17 people. In a five-year naturalistic study, 30.5% of patients taking clozapine were eventually diagnosed with Type 2 diabetes. With olanzapine, a total of 10 cases of hyperglycaemia and 5 cases of ketoacidosis have been published. Reports of hyperglycaemia with other atypicals are relatively scarce. The association of hyperglycaemia or ketoacidosis with clozapine and olanzapine appears to be a true drug-induced effect. Risk factors may include male gender, age of around 40 years and being non-Caucasian. The management of hyperglycaemia depends on the causative agent. With clozapine, treatment with oral hypoglycaemics has been successful. With olanzapine, other atypical antipsychotics may be considered. Blood glucose monitoring is essential for all patients starting clozapine or olanzapine.

Adult↗
PubMed2000

Potential prophylactic use of benzodiazepines for hemodialysis-associated seizures.

Hemodialysis-associated seizure (HAS) is a common complication of hemodialysis. The efficiency of anticonvulsant drugs in treating or preventing seizures is poorly defined. In this study, children on long-term hemodialysis were examined for HAS and the effect of diazepam prophylaxis on HAS was investigated. Nine patients with a mean age of 14.1 + 2.8 years had HAS and 4 with a mean age of 13.0 +/- 4.4 years had never experienced HAS. The patients with HAS had tonic-clonic seizures. Four patients had focal slow-wave paroxysms, especially in the parieto-occipital regions; 2 had subcortical epileptiform discharges by electroencephalography. No correlation was observed between HAS and patient age, primary disease, prior history of seizures, type of dialysis, duration of hemodialysis, anemia, hyperparathyroidism, and administration of erythropoietin. Hypertension due to hypervolemia may also play a role in the development of HAS. Five patients with HAS first treated with phenobarbital (PB) had recurrence of seizures. As a dialyzable antiepileptic PB may be associated with an increased risk for HAS. In a preliminary study, we gave diazepam as a prophylactic therapy to 4 patients with HAS. During 6 months of follow-up, these patients had no seizures. The number of HAS was significantly different between the groups receiving PB and diazepam (z=-2,58, P=0.009). In conclusion, administration of diazepam per os to patients with HAS may be of value for preventing recurrence of HAS.

Adolescent↗
PubMed1999

Clinicopathologic correlations of Henoch-Schönlein nephritis in Turkish children.

BACKGROUND: In this study, 66 patients with Henoch-Schönlein nephritis (HSN) were investigated clinicopathologically. METHODS: The patients were classified according to their initial presentation, histologic findings, recurrences of purpura, type of treatment and clinical outcome. Logistic regression analysis was performed. RESULTS: Sixty-eight percent of patients were hospitalized with mild renal disease. Most patients were evaluated as class I and II according to light microscopy. In addition to IgA deposition alone, 33% of patients showed IgA + C3 and 27% had IgA + IgG + C3 depositions. After the follow-up period of 3.3 years, 15 patients had minor urinary findings, 4 had active renal disease and 1 had renal insufficiency. Recurrences occurred in 37.9% of patients and 37.1% of patients with recurrences had persistent pathologic findings. Symptomatic treatment was given to 51.5% of patients, while 27.2% were given corticotherapy. CONCLUSIONS: Clinical presentation was found to be correlated with outcome. Recurrence of the disease and the type of the treatment also affected the outcome. It was also thought that mesangial IgG and C3 depositions may have a role in the pathogenesis of renal damage in HSN.

Adolescent↗
PubMed1998

Effect of enalapril on proteinuria, phosphaturia, and calciuria in insulin-dependent diabetes.

Elevated urinary calcium and phosphate excretion have been observed in children with insulin-dependent diabetes mellitus (IDDM). This may be related to a defect in tubular reabsorption. It is well known that converting enzyme inhibition decreases microalbuminuria and may prevent or retard diabetic nephropathy. We investigated whether enalapril also improves the defect in calcium and phosphate reabsorption. We studied 16 children and young adults (age 12-21 years) with IDDM and persistent microalbuminuria before and during 12 weeks of enalapril treatment. Before treatment microalbuminuria, urinary calcium excretion, and fractional tubular phosphorus reabsorption (TPR) were 153+/-53 microg/min, 5.5+/-0.9 mg/kg per day, and 71.4+/-3.6%, respectively. At the end of the 12th week, microalbuminuria had decreased to 20.3+/-7.9 microg/min and calcium excretion to 3.3+/-0.4 mg/kg per day (P<0.01), while the TPR increased to 80.1+/-3.8% (NS). The renal threshold phosphate concentration increased from 1.8+/-0.15 to 2.92+/-0.23 mg/dl (P<0.01). The fasting serum glucose and hemoglobin Alc levels did not change significantly during the study. Systolic and diastolic blood pressures were 120.4+/-2.2 / 79.3+/-1.4 mm Hg and 110.5+/-1.8 / 71.3+/-0.9 mm Hg before and after 12 weeks, respectively. We conclude that enalapril treatment improves not only microalbuminuria but also abnormal calcium and phosphate excretion in microalbuminuric children with IDDM.

Adolescent↗
PubMed1998

Plasma and urinary platelet activating factor concentrations and leukotriene releasing activity of leukocytes in steroid sensitive nephrotic syndrome of childhood.

Platelet activating factor (PAF) is synthesized and secreted by glomerular mesangial and endothelial cells. It increases glomerular basement membrane permeability and induces proteinuria. Leukotrienes (LT) are mediators released by either leukocytes or glomerular cells under the PAF effect. The possible role of PAF in steroid sensitive nephrotic syndrome (SSNS) of childhood was studied in 8 children with SSNS in the acute stage, 5 children in remission and 8 healthy controls. The PAF concentrations in urine and plasma were determined. Leukocytes were stimulated in vitro and the LT release in response to stimulation was determined. The urinary and plasma concentrations of PAF were significantly higher in the acute phase than in remission and in control patients. Children with SSNS were found to have peripheral leukocytes with increased LT releasing activity in vitro. These results are in accordance with clinical and experimental observations indicating that PAF originates in the kidney and plays a role in normal kidney physiology. Urinary PAF concentrations may be related to proteinuria because they were strongly correlated in the present study. Elevated plasma PAF concentrations in the acute stage of SSNS could result from either its secretion from the circulating leukocytes or decreased acetyl hidrolase activity needed for its hydrolysis in plasma. The increased LT release in vitro suggests that these cells might have been activated by PAF secreted from glomeruli. It is proposed that PAF and different LT in systemic and glomerular circulation are important mediators in childhood SSNS.

Adolescent↗
PubMed1998

Pindolol augmentation of antidepressant therapy.

BACKGROUND: Antidepressant therapy is not always effective and is slow to take effect. In theory, these shortfalls may be caused by induction of neuronal negative feedback via pre-synaptic 5-HTIA receptors. Pindolol, an antagonist at somatodentritic pre-synaptic 5-HTIA receptors has been investigated as a potential accelerator and augmentor of antidepressant response. METHOD: A Medline search was conducted in November 1997. RESULTS: Six open-label studies and six controlled studies were identified for review. CONCLUSIONS: Open-label studies strongly suggest that pindolol may accelerate and augment antidepressant response, but controlled studies do not wholly support these findings: only three of six studies clearly demonstrate benefit. Larger, well-designed, controlled trials are needed to determine definitively the effectiveness of pindolol in this context.

Adrenergic beta-Antagonists↗
PubMed1998

Does immunologic status predict peritonitis in children treated with CAPD?

The purpose of this study was to evaluate whether immunologic status could predict the development of peritonitis in children on continuous ambulatory peritoneal dialysis (CAPD). Twenty-one patients (12 boys, 9 girls) aged 10.1 +/- 4.32 years (range: 23 months to 14 years) were studied. The mean duration of CAPD treatment was 12.88 +/- 6.69 months (range: 2-22 months). Twelve healthy children (mean age 11.5 years) were selected as a control group. Lymphocyte subpopulations (CD3, CD4, CD8, CD19, NK, and IL-2R) were determined by double-color flow cytometry (Becton-Dickinson). Statistical evaluation was made by Student's t-test. CD4 (38.4 +/- 7.1% vs. 28.0 +/- 5.4%), CD4/CD8 ratio (1.30 +/- 0.4 vs. 0.96 +/- 0.3), and B lymphocyte (19.9 +/- 8.9% vs. 12.0 +/- 3.2%) levels were significantly higher in CAPD patients compared with controls. CAPD patients showed significantly lower natural killer (NK) cell values than controls (12.7 +/- 7.0% vs. 27.3 +/- 8.3%). Apart from CD19 values (21.9 +/- 10.4% vs. 12.0 +/- 3.2%) there were no significant differences between CAPD patients without infection and the control group in the laboratory parameters studied. On the other hand, CD3 (66.3 +/- 7.9% vs. 55.9 +/- 9.7%), CD4 (38.4 +/- 7.1% vs. 28.0 +/- 5.4%), and CD19 (6.3 +/- 3.3% vs. 12.0 +/- 3.2%) levels were significantly higher in CAPD patients with infection compared with the controls. CAPD patients with infection showed significantly lower NK activity (12.7 +/- 7.1% vs. 27.3 +/- 8.3%) than those in the control group. In conclusion, these results can explain the increased vulnerability to peritonitis in CAPD patients compared with healthy subjects. Additionally, immunologic status can predict the development of peritonitis in children treated with CAPD.

Adolescent↗
PubMed1998

A comparative histologic study of the fibrillin microfibrillar system in the lens capsule of normal subjects and subjects with Marfan syndrome.

PURPOSE: To gain a better understanding of the pathogenesis of ectopia lentis and myopia in Marfan syndrome, studies were performed to determine the distribution and structure of fibrillin microfibrils in the lens capsule of normal subjects and of subjects with Marfan syndrome. METHODS: Frozen sections and/or flat mounts of lens capsules were prepared from six autopsy eyes, nine surgical capsulotomy specimens obtained at the time of cataract extraction, and five capsules from patients with Marfan syndrome obtained at intracapsular lens extraction. Avidin-biotin-peroxidase complex (ABC) immunoperoxidase or immunofluorescence staining with monoclonal antifibrillin antibody was used to localize fibrillin in lens capsules. Image analysis was also performed to compare the amount of fibrillin expression in normal and Marfan syndrome capsules. RESULTS: Based on fibrillin staining patterns, we identified three distinct zones in the equatorial and periequatorial regions of the normal lens capsule. Zone I, a 0.75-mm-wide peripheral ring of the anterior capsule, contained radial bundles of fibrillin fibers. In Zone II, a 1-mm-wide meshwork of fibrillin-rich fibers encircled the equator and served as an insertion platform for zonular fibers. Zone III was composed of radial, 0.1-mm-wide bands arranged in a periodic fashion in the most peripheral part of the posterior capsule. Fibrillin fibers were abnormal and disrupted in all three zones in patients with Marfan syndrome. The amount of fibrillin staining per unit area was significantly reduced in Marfan capsules compared with normal capsules (16-26% versus 49-56% per unit area, respectively; P < 0.001). CONCLUSIONS: Fibrillin was a major constituent of the peripheral and equatorial areas of the lens capsule. Zonular fibers, also rich in fibrillin, insert into the equatorial region, primarily in Zone II. Possibly, fibrillin played a role in the ability of the lens to change its configuration during accommodation. The observed qualitative and quantitative abnormalities in fibrillin expression in the lens capsule of patients with Marfan syndrome supported a causal relationship to lens abnormalities in these patients.

Actin Cytoskeleton↗
PubMed1996

The adjustment of post-dialysis dry weight based on non-invasive measurements in children.

BACKGROUND: The clinical criteria to assess hydration status are not always reliable. Hence, the development of techniques to estimate more accurately post-dialysis dry weight (DW) remains a major challenge. The present study evaluates the value of the inferior vena cava (IVC) diameter, plasma concentration of atrial natriuretic peptide (ANP), and plasma renin activity (PRA) in determining the DW in chronic haemodialysis children. METHODS: Twelve overhydrated haemodialysis patients (4 girls, 8 boys) with a mean age of 12.8 were admitted to the study. Clinical, electrocardiographic, telecardiographic and echocardiographic findings, IVC and collapsibility indices and plasma concentrations of ANP and PRA were investigated before and after ultrafiltration (UF) therapy. Twelve age-matched normal children were studied as controls. Analysis of variance and Dunnett's test were applied for comparisons between patients and controls. RESULTS: Following UF therapy the patients' mean IVC collapsibility index was increased from 42.3 to 53.6% and IVC index was decreased from 1.08 to 0.81 cm/m2, both statistically significant. The pre-UF therapy collapsibility and IVC indices of the patient group were significantly different from those of the control group (56.9% and 0.70 cm/m2 respectively). The patients' mean plasma concentrations of ANP were 171 +/- 47.4 pg/ml before UF, 129 +/- 51.3 pg/ml after UF and 102 +/- 38.7 pg/ml in the control group. The ANP levels of the patients showed a significant decrease following the UF therapy. PRA was measured as 0.82 ng/ml/h before UF and 1.08 ng/ml/h after UF, but the increase was not statistically significant. CONCLUSIONS: Our findings revealed increased diameter of the IVC and plasma ANP concentrations and decreased collapsibility due to overhydration. Echography of IVC may be a promising non-invasive tool to estimate the DW in haemodialysis children. Further studies providing normative values for the IVC indices in both haemodialysis and normal children are required.

Adolescent↗
PubMed1995

Image-directed and color Doppler ultrasonography in the diagnosis of postbiopsy arteriovenous fistulas of native kidneys.

Using image-directed and color Doppler ultrasonography (ICDUS), we examined 65 patients with single kidney biopsy and diagnosed one arteriovenous fistula (AVF) in each of 8 kidneys. Three of them were associated with pseudoaneurysms. Three of the patients with AVF who presented with macrohematuria underwent angiography. Therapeutic percutaneous embolization was performed in 2 of them. The remaining 6 patients were followed up with ICDUS. All the lesions had disappeared at the end of a 6-month period. We conclude that ICDUS is an easy and noninvasive imaging technique in the diagnosis of postbiopsy native renal AVFs.

Adolescent↗
PubMed1995

Lymphocyte subpopulations in children with vitamin D deficient rickets.

Recent studies have shown 1,25(OH)2D3-mediated modulation of the immune system. We examined lymphocyte subpopulations of 16 children with nutritional rickets. Most of the patients suffered more frequent infection episodes than the control group of 15 healthy children and low serum levels of 25OHD and 1,25(OH)2D, such as 38.2 +/- 8.6 ng/mL and 15.7 +/- 2.6 pg/mL respectively. This decrease correlated with a significant decrease in total T lymphocytes and an increase in B lymphocytes expressing surface IgA, IgM, IgG molecules. These results suggest that vitamin D plays an important role in the impaired functions of T lymphocytes which may lead to frequent infection episodes in nutritional rickets.

Child, Preschool↗