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Biomedical subjects

S Sarnaik

Publications and source records attributed to S Sarnaik.

At least 19 recordsLinked to original sources
PubMed2001

Characterization of pica prevalence among patients with sickle cell disease.

OBJECTIVE: To determine the prevalence of pica and its characteristics among children with sickle cell disease. DESIGN: Retrospective, observational study. SETTING: An urban, ambulatory care, interdisciplinary center. PATIENTS: The medical records of all 480 patients who visited the center from March 1, 1998, to June 30, 1999, were reviewed. Patients were excluded for history of stroke, long-term transfusions, pregnancy, acute illness, or age younger than 3 years. MAIN OUTCOME MEASURES: Sex, age, weight, height, Tanner stage, complete blood cell count, sickle cell genotype, pica history, and levels of iron, zinc, lead, and fetal hemoglobin (Hb). RESULTS: Of 395 study patients, 134 (33.9%) reported pica. Ingested items included paper, foam, and powders. There was a significantly higher prevalence of pica among patients homozygous for Hb S (Hb SS, sickle cell anemia) compared with the combined group of double heterozygous patients with Hb SC, Hb SD, and Hb Sbeta thallasemia (Sbeta(+)or Sbeta(0)) (35.6% vs 25.5%; P =.03). Within genotype, mean Hb levels were significantly lower and reticulocyte counts were significantly higher in the patients with pica. Overall, the mean age of patients with pica was significantly lower; however, the prevalence was 23.3% (27/116) among those aged 10.0 to 14.9 years and 14.8% (8/54) among those aged 15.0 to 19.0 years. Within age groups, patients with pica weighed significantly less. CONCLUSIONS: Pica appeared to have an unusually high prevalence in patients with sickle cell disease and a correlation with lower Hb levels. It is unclear whether pica is a specific marker of disease severity, because our review did not show a relationship to increased number and duration of hospitalizations. The association between pica and low body weight suggests a nutritional effect on its prevalence.

Adolescent↗
PubMed1999

Imaging of sickle cell disease.

Sickle cell disease is an important health care issue in the United States and in certain areas in Africa, the Middle East and India. Although a great deal of progress has been made in understanding the disease at the molecular and pathophysiologic level, specific treatment which is safe and accessible for most patients is still elusive. Going into the next millennium, the management of this disease is still largely dependent on early diagnosis and the treatment of complications with supportive care. Thus, diagnosis and evaluation of the complications of the disease are crucial in directing clinical care at the bedside. Modern imaging modalities have greatly improved, and their application in the patient with the sickling disorders has enhanced the decision - making process. The purpose of this article is to review the clinical aspects of common complications of the disease and to discuss imaging approaches which are useful in their evaluation.

Anemia, Sickle Cell↗
PubMed1999

Biodegradation of methyl violet by Pseudomonas mendocina MCM B-402.

Pseudomonas mendocina MCM B-402 was found to utilize a triphenylmethane dye, methyl violet as the sole source of carbon when incorporated in synthetic medium. Almost complete decolorization of methyl violet by P. mendocina was observed within 48 h of incubation at ambient temperature (28 +/- 2 degrees C) under aerated culture conditions, when the bacteria were inoculated into Davis Mingioli's synthetic medium at a concentration of 100 mg/l medium. Methyl violet was mineralized to CO2 through three unknown intermediate metabolites and phenol. The decolorization of the dye involved demethylation.

Biodegradation, Environmental↗
PubMed1999

Low frequency of meperidine-associated seizures in sickle cell disease.

Pain control measures in sickle cell diseases are not uniform. Most clinicians use parenteral morphine or meperidine for severe pain. Reports of seizures associated with meperidine have led to a growing reliance on intravenous morphine, usually with patient-controlled devices. Acceptance of morphine has been poor among patients, and many prefer meperidine. The aim of this retrospective study was to determine the incidence of meperidine-associated seizures in a large, mostly pediatric population with sickling disorders. The results suggest that the incidence of seizures with meperidine is extremely small (0.4% of patients; 0.06% of admissions). The risk of seizures should not dissuade clinicians from using this drug.

Adolescent↗
PubMed1998

Prevalence of microalbuminuria in children with sickle cell disease.

Renal involvement is common in homozygous sickle cell disease (HbSS), including glomerular hypertension and hypertrophy similar to that seen in rodent models of ablative nephrectomy and stage I diabetic nephropathy (DN). The proteinuria in the rodent models is attenuated by angiotensin converting enzyme inhibition (ACEI). Microalbuminuria (MA) is a sensitive marker for renal involvement in DN prior to the development of proteinuria, and is also attenuated with ACEI. Elevated urinary microalbumin/creatinine ratios (U Alb/Cr) >20 mg/g Cr are reported in 39%-43% of adults with HbSS, and studies are ongoing in this age group to assess the effect of attenuated proteinuria by ACEI on long-term renal function. The purpose of this study was to prospectively investigate the prevalence of MA in children with HbSS and determine factors which affect its expression. U Alb/Cr values were measured on spot urine samples in 102 children (aged 2-18 years, mean 9.47+/-4.62, M:F=53:49) by rate nephelometry. Children with prior known proteinuria, hypertension, or fever/pain episode in the last 15 days were excluded. MA was present in 26.5% of all children with HbSS. However, in children between the ages of 10 and 18 years, the prevalence was 46% (similar to the prevalence in adults). There was a strong correlation between patient age and prevalence of MA (P<0.0001) by both univariate and multivariate analysis. However, pain frequency, hospitalization, transfusion program, ferritin levels, and Cr clearance (C(Cr)) did not correlate with prevalence, although C(Cr) (as estimated by Schwartz formula) was elevated in all. We conclude that the prevalence of MA in the 2nd decade of life is similar to that in adults.

Adolescent↗
PubMed1996

Hematology.

Explore the source record for details and available documents.

Blood Coagulation Factors↗
PubMed1996

Priapism associated with sickle cell hemoglobinopathy in children: long-term effects on potency.

PURPOSE: Children with sickle cell priapism have traditionally been treated conservatively with surgery done as a last resort. Only sparse subjective data are available on the long-term assessment of potency in these patients. MATERIALS AND METHODS: We retrospectively reviewed the charts of all pediatric patients with sickle cell priapism who presented to Children's Hospital of Michigan between 1972 and 1992, and subsequently assessed erectile capabilities subjectively by questionnaire and objectively by RigiScan. RESULTS: Of the 15 patients interviewed 5 had undergone shunt procedures. The return of potency tended to vary inversely with patient age at onset and duration of priapism. CONCLUSIONS: Shunts performed within 48 hours, especially in postpubertal children, seemed more likely to preserve potency.

Adolescent↗
PubMed1995

Blood transfusions and immunophenotypic alterations of lymphocyte subsets in sickle cell anemia. The Transfusion Safety Study Group.

Transfusions purportedly induce dysfunction of cell-mediated immunity in sickle cell anemia (SCA). We studied hematologic and lymphocytic indices in 173 human immunodeficiency virus (HIV)-negative subjects with SCA and 131 black controls. Children aged 1 to 7 years with SCA had leukocyte counts and percentages of granulocytes, monocytes, natural killer cells, and T-cell markers (CD2+CD11b+, CD4+CD26+, CD4+CD29+) that were significantly higher than those for control children. Percent total lymphocytes was decreased for this age group, but the total number of lymphocytes and T and B cell counts were similar to controls. Platelets were not increased. Adolescents (aged 8 to 17 years) and adults (aged > or = 18 years) with SCA had increased total leukocytes and monocytes and lymphocytes counts that remained level instead of decreasing, as did comparably aged controls. Lymphocyte subsets typically increased in count, but their percentage remained similar to children. The exception was CD56+ cell counts, which were increased in adolescents and adults. No lymphocytic subset change suggested impaired cellular immunity, and none could be related to transfusion. Prophylactically transfused patients had higher granulocyte counts, but these may arise from the complications of SCA itself.

Adolescent↗
PubMed1994

Bepridil as an antisickling agent: membrane internalization and cell rigidity.

The calcium channel antagonist, bepridil, beta-(2-methylpropoxy)methyl-N-phenyl-N-(phenylmethyl)-1-pyrrol idineethanamine monochloride monohydrate, inhibits the sickling of deoxygenated sickle (SS) erythrocytes, as determined by light microscopy. The anti-sickling effect was seen only in dilute suspensions of red cells. In concentrated erythrocyte suspensions, sickling was not inhibited and measurements of hematocrit and cell density were unchanged by bepridil. The determination of cell volume in dilute suspensions was complicated by bepridil's tendency to aggregate, but rapid measurements by electronic sizing also indicated no increase in cell volume, up to a bepridil concentration of 200 microM. Ektacytometry of dilute sickle cell suspensions suggested an explanation for the anti-sickling action of bepridil. Osmotic scan ektacytometry disclosed that bepridil initially increased the surface area of the red cell, as shown by a shift in the low osmolality minimum. This change was complete in 10 sec, the shortest time that could be measured. Subsequently, at concentrations that were observed to inhibit the sickling of deoxygenated sickle cells (100 microM or greater), red cells underwent a loss in surface area that was complete in 1 min. There was a concomitant loss of cell deformability. Light and scanning electron microscopy has previously shown that bepridil is a stomatocytic agent. Using transmission electron microscopy, we verified that the loss of surface area was a consequence of endocytosis, presumably as the end stage of the stomatocytic transformation induced by bepridil. Bepridil did not inhibit intracellular hemoglobin S polymerization even at 200 microM, as shown by oxygen scan ektacytometry. Bepridil thus appears to inhibit the sickling of deoxygenated SS cells by inducing endocytosis and lowering cell deformability. This mechanism may explain the anti-sickling effect of other basic amphiphiles, such as chlorpromazine.

Anemia, Sickle Cell↗
PubMed1990

Mechanical properties of sickle cell membranes.

The mechanical properties of sickle erythrocyte membranes were evaluated in the ektacytometer. When ghosts from the total red blood cell population were examined, the rigidity of the resealed ghosts and their rate of fragmentation by shear stress (t1/2) were normal. However, fractionation on Stractan density gradients revealed that sickle cells were heterogenous in their membrane mechanical properties. The ghosts from dense cell fractions exhibited both increased rigidity and decreased stability. Presumably, these altered mechanical properties are a reflection of the well-documented biochemical damage found in irreversibly sickle cell membranes. Nevertheless, neither of the alterations in mechanical properties are likely to be significant elements in the hemolysis of sickle cell anemia. Earlier studies of abnormal erythrocytes suggest that increases in membrane rigidity per se do not increase hemolysis, and they are, therefore, unlikely to do so in this case. The stability of membranes from the dense cell fractions was reduced to about two thirds of the control value. Comparison with the results of studies of red blood cell membranes with genetically defective or deficient spectrin suggests that a reduction in t 1/2 of 50% is not associated with significant increases in the rate of hemolysis. Although altered ghost stability and flexibility can be demonstrated in dense sickle cells, these changes in membrane mechanical properties are not likely to be significant factors in the hemolytic process.

Anemia, Sickle Cell↗
PubMed1990

Studies on Pneumococcus vaccine alone or mixed with DTP and on Pneumococcus type 6B and Haemophilus influenzae type b capsular polysaccharide-tetanus toxoid conjugates in two- to five-year-old children with sickle cell anemia.

Pneumococcus vaccine, injected alone or mixed with diphtheria-tetanus toxoid-pertussis, did not elicit significant concentrations of pneumococcus type 6 antibodies in 2- to 5-year-old sickle cell anemia patients (n = 22). Reinjection 5 months later failed to elicit a booster response to pneumococcus type 6. We then injected conjugates of pneumococcus type 6B and of Haemophilus influenzae type b (Hib), each bound to tetanus toxoid (TT), alternatively at monthly intervals into sickle cell anemia patients of the same age group (n = 25); most received 3 injections of each vaccine. Pneumococcus vaccine was administered to 19 patients and Hib to 1 at approximately 1 year of age. Blood samples were taken before each and approximately 6 months after the last injection. Infrequent and minimal local reactions and only 6 episodes of fever (3%) occurred after injection of the conjugates. Pneumococcus type 6B-TT elicited a rise in the geometric mean concentration of pneumococcus type 6 antibodies (Ab) from 104 ng of antibody nitrogen (AbN)/ml in preimmunization sera to 385 ng of AbN/ml after the first injection (P less than 0.01). There were further increases after the 2 subsequent injections; 6 months after the third injection, the mean concentration was 940 ng of AbN/ml and 15 of 16 (94%) had greater than 300 ng of AbN/ml. Hib-TT elicited a 160-fold increase of Hib antibodies to a geometric mean concentration of 39.0 micrograms of Ab/ml after the first injection. These levels rose approximately 2-fold following 2 additional injections to 71.7 micrograms/ml and declined to 10.7 micrograms/ml at the 6-month sampling.(ABSTRACT TRUNCATED AT 250 WORDS)

Anemia, Sickle Cell↗
PubMed1990

Delayed intracranial hemorrhage following cerebral infarction in sickle cell anemia.

Clinical and necropsy findings in 11 patients with sickle cell anemia (SS) indicate that intracranial hemorrhage (IH) is a delayed sequela of the same vasculopathy that causes cerebral infarction during childhood. Evidence of prior cerebral infarction during childhood included hemiparesis, seizures, an episode of coma, or mental retardation. Computerized tomography (CT) scans showed cerebral infarcts with lucent areas and dilated ventricles or cerebral atrophy. CT or magnetic resonance imaging (MRI) scans after the intracranial hemorrhage demonstrated intraventricular or intracerebral hemorrhages. Angiography or autopsy in seven patients showed widespread vascular occlusion and narrowing of arterial vessels. Moyamoya with internal carotid artery occlusion was identified in two cases. At the time of the IH, three patients were being treated with prophylactic transfusion regimens. We hypothesize that the central nervous system vasculopathy progresses over time and that arterial narrowing in both large and small vessels secondary to endothelial hyperplasia is followed by neovascularization and hemorrhage. Recognition of this pattern of delayed intracranial hemorrhage following cerebral infarction should encourage more intensive evaluation aimed at developing rational interventional therapy prior to a terminal intracranial hemorrhage.

Adolescent↗
PubMed1986

Sickle-cell nephropathy: MR imaging.

To study the nephropathy associated with sickle-cell disease (SCD), spin-echo magnetic resonance (MR) imaging of the kidneys was performed in 19 SCD patients, six with beta-thalassemia major (BTM), and ten healthy individuals as controls. Eleven SCD patients had decreased relative cortical signal, most evident on T2-weighted images. No correlation with serum ferritin, urine-concentrating ability, serum blood urea nitrogen, or creatinine levels was established. Iron deposition in the renal cortices of sickle-cell nephropathy patients may, at least in part, be responsible for the relatively diminished cortical signal intensity. No BTM patients, all of whom were clinically and biochemically in iron overload from frequent transfusions, demonstrated diminished renal cortical signal intensity. This suggests that renal changes in SCD seen on MR images are not due simply to systemic iron overload per se but perhaps reflect abnormalities of iron metabolism in the renal cortex peculiar to SCD nephropathy.

Adolescent↗
PubMed1986

Revaccination with polyvalent pneumococcal vaccine in children with sickle cell anemia.

To determine if revaccination improves levels of antibodies to pneumococcal polysaccharide types 6A, 14, and 19, 86 subjects with sickle cell anemia between 4 and 23 years old were given a booster injection of a polyvalent pneumococcal vaccine 37 to 53 months after primary immunization. Most subjects had mild local reactions similar to those seen after primary immunization. Only two subjects, both young adults, had severe local and systemic reactions. The percentages of subjects with protective antibody levels to types 6A, 14, and 19 increased from 74%, 44%, and 79% respectively before boosting, to 92%, 66%, and 92% respectively after boosting. Revaccination of children and young adults with sickle cell anemia appears to result in increased protective levels of antibody, and is associated with a low prevalence of severe reactions.

Adolescent↗
PubMed1984

Diminished helper/suppressor lymphocyte ratios and natural killer activity in recipients of repeated blood transfusions.

Immunologic abnormalities qualitatively similar to those seen in acquired immunodeficiency syndrome (AIDS), including a low helper/suppressor lymphocyte ratio and low natural killer (NK) activity, have been observed in many hemophiliacs receiving clotting factor concentrates. To determine whether these changes also occur after repeated blood transfusion, we measured helper/suppressor (T4/T8) ratios and NK activity in four groups of test subjects: (A) 30 subjects with sickle cell anemia (SCA) receiving monthly transfusions, (B) 30 nontransfused sickle cell anemia subjects, (C) 87 individuals with hemophilia or severe von Willebrand's disease, and (D) 30 normal controls. Like the hemophiliacs, transfused SCA subjects had low T4/T8 ratios and low NK activity compared to controls. Nontransfused SCA subjects had normal values. These findings suggest that a modest decrease in T4/T8 ratio and NK activity may be part of the normal immune response to repeated transfusion.

Adolescent↗