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Biomedical subjects

M Majd

Publications and source records attributed to M Majd.

At least 19 recordsLinked to original sources
PubMed1997

Imaging in pediatric urology.

A multitude of disorders of the genitourinary tract can occur in children. Although some entities may be diagnosed clinically, radiologic imaging is often necessary for diagnosis and management. The radiologic work-up has been discussed using a problem-oriented approach in five clinical situations: urinary tract infection, hydronephrosis or hydroureter, trauma, swollen scrotum, and hematuria. This discussion provides some general guidelines, although the evaluation of each child may need to be individualized depending on their specific clinical symptomatology.

Acute Disease↗
PubMed1997

In-111 pentetreotide scintigraphy in patients with neuroblastoma. Comparison with I-131 MIBG, N-Myc oncogene amplification, and patient outcome.

OBJECTIVE: 1. To evaluate the relative efficacy of In-111 pentetreotide and 1-131 radioiodinated meta-idobenzyl guanidine (MIBG) for detection of primary and metastatic neuroblastoma. 2. To assess the prognostic value of In-111 pentetreotide uptake. METHODS AND MATERIALS: Seven In-111 pentetreotide and seven I-131 MIBG scans were obtained in six patients with stage IV neuroblastoma and 1 with stage III ganglioneuroblastoma. Three scans were obtained at initial staging and four were obtained during therapy. Correlation was made with concomitant computed tomography scans, bone scans, N-myc oncogene amplification, and clinical outcome. RESULTS: Primary tumor was present in six patients and had been resected in 1. In-111 pentetreotide uptake was seen in two of six primary tumors, I-131 MIBG scan was positive in five of six. In-111 pentetreotide scan was positive in two of four patients with bone metastases, I-131 MIBG scan was positive in three of four. Both showed liver metastases in one patient and did not show bone marrow metastases in another. Overall sensitivity for primary or metastatic disease was 57% (four of seven) for In-111 pentetreotide and 86% (six of seven) for MIBG. Correlation between N-myc oncogene and In-111 pentetreotide uptake was seen in four of seven patients. In-111 pentetreotide uptake correlated with the clinical outcome in six patients with more than 1 year follow-up. Two patients with negative In-111 pentetreotide scans had unfavorable outcome. One patient died, and the other had local recurrence 15 months after diagnosis. Four patients with a positive scan are alive without disease on follow-up at 13-31 months after diagnosis. CONCLUSION: In-111 pentetreotide scintigraphy is less sensitive than I-131 MIBG for detecting active neuroblastoma. In-111 pentetreotide uptake on scintigraphy may correlate with the prognosis. However, a larger series of patients is needed for further evaluation.

3-Iodobenzylguanidine↗
PubMed1996

The role of 131 iodine-metaiodobenzylguanidine scanning in the correlative imaging of patients with neuroblastoma.

OBJECTIVE: Metaiodobenzylguanidine (MIBG) scans were studied to determine the impact of the scan results on the clinical treatment of pediatric patients with neural crest tumors. METHODS: Serial scans were reviewed retrospectively for 27 patients with neural crest tumors: 25 with initial diagnoses of neuroblastoma (NB), 1 with ganglioneuroblastoma, and 1 with ganglioneuroma (GN). Results were compared with bone scans and computed tomography scans, as well as surgical pathologic findings. RESULTS: At initial diagnosis, when compared with bone and computed tomographic scans, MIBG imaging did not identify any unsuspected lesions that resulted in a change in staging. Thirteen patients with NB who had initially positive MIBG scan results had serial studies that normalized during therapy. However, after completion of therapy, 8 of 13 had relapses of the disease. Although areas of active disease were well delineated by other standard imaging modalities for all 8, only 4 (50%) had MIBG study results that were positive in sites of relapse. There were 4 cases of GN (1 at diagnosis and 3 after therapy for NB) demonstrating an uptake of MIBG that was similar in appearance to that in NB. CONCLUSIONS: MIBG imaging did not change the staging or alter treatment during therapy for any patient. Normalization of positive study results was an unreliable indicator of outcome for children with NB. Furthermore, when relapse occurred, MIBG scans identified only 50% of those with active NB. The uptake of MIBG in GN was indistinguishable from that in NB. In this series, the results of serial MIBG studies did not have a significant impact on patient treatment.

3-Iodobenzylguanidine↗
PubMed1996

Technetium-99m-DMSA renal cortical scintigraphy to detect experimental acute pyelonephritis in piglets: comparison of planar (pinhole) and SPECT imaging.

UNLABELLED: The purpose of this study was to directly compare the sensitivity and specificity of SPECT and pinhole imaging for the detection of acute pyelonephritis using histology as the standard of reference. METHODS: Bilateral vesicoureteral reflux of infected urine was induced in 16 piglets (32 kidneys) by unroofing the intravesical ureter and subsequently instilling a broth culture of E. coli into the bladder. DMSA scans were obtained by both pinhole and SPECT techniques at 24 hr (4 piglets), 48 hr (5 piglets), 72 hr (4 piglets) and 10 days (3 piglets) after instillation of bacteria into the bladder. Kidneys were harvested immediately after scintigraphy for histopathologic examination. Results of the SPECT images, pinhole images and histologic findings were interpreted independently in a blinded fashion. The images of each kidney were classified as positive or negative for pyelonephritis regardless of the severity and number of lesions. To evaluate accuracy of SPECT and pinhole imaging for the detection of individual lesions, each kidney was arbitrarily divided into three zones (upper, middle and lower). Image findings were then compared with the pathology results for the presence or absence of pyelonephritis in each zone. RESULTS: Histopathology revealed pyelonephritis in 24 of 32 kidneys (58 of 96 zones). The sensitivity of the DMSA scan for detection of affected kidneys was 92% for SPECT and 83% for pinhole; overall accuracy was 88% for both. The sensitivity of SPECT for the detection of affected renal zones was slightly better than pinhole imaging (91% compared with 86%), but its specificity was lower (82% compared with 95%) resulting in a similar accuracy. Excluding four piglets where scans were obtained within 24 hr after instillation of bacteria into the bladder, the sensitivity of SPECT and pinhole for the detection of affected kidneys were 95% and 90%, respectively. Their overall accuracy were 96% and 92%. In this subgroup, the sensitivity, specificity and accuracy of SPECT for the detection of involved zones were 96%, 95% and 96%, respectively. The corresponding values for pinhole imaging were 90%, 95% and 92%, respectively. CONCLUSION: Although the sensitivity of SPECT for the detection of acute pyelonephritis is slightly better than pinhole DMSA scan, the overall accuracy of these two imaging techniques is essentially the same.

Acute Disease↗
PubMed1995

Relationship of asymptomatic bacteriuria and renal scarring in children with neuropathic bladders who are practicing clean intermittent catheterization.

OBJECTIVE: To determine whether untreated asymptomatic bacteriuria is associated with renal scarring in children with neuropathic bladders managed with clean intermittent catheterization (CIC). DESIGN: Retrospective study of 207 patients aged 1 to 30 years (mean 11.9 +/- 5.5 years) treated with CIC for a mean duration of 6.6 +/- 3.9 years by the spina bifida program at Children's National Medical Center. All patients were examined for renal scarring with dimercaptosuccinic acid (DMSA) renal scans. Catheterized urine cultures were obtained annually, but bacteriuria ( > 10,000 colony-forming units of a single organism per milliliter) was treated only if the patients had symptoms or if vesicoureteral reflux (VUR) was present. RESULTS: Of 207 children, 176 (85%) had one or more episodes of untreated asymptomatic bacteriuria and 72 (35%) had one or more febrile episodes associated with positive urine culture results. Biannual DMSA scans detected 54 new scarring episodes in 42 patients. Of newly recognized scars, 55% were preceded within 1 year by a febrile infection, 26% were detected in patients with VUR and asymptomatic bacteriuria, and 19% were detected in new patients during their initial examination. Univariate analysis revealed that new scarring was present in 35 of 176 patients with asymptomatic bacteriuria compared with 7 of 31 patients without (p = 809). Logistic regression analysis revealed that factors associated with scarring were febrile infections (adjusted odds ratio [OR] = 30.6, 95% confidence interval [CI] = 9.8 to 95.8), age more than 20 years (OR = 4.3, CI = 1.01 to 18.5), the presence of bladder trabeculation (OR = 2.7, CI = 1.0 to 7.6), and VUR (OR = 58.8, CI = 6.3 to 547.3), but asymptomatic bacteriuria was not associated with scarring. CONCLUSION: In the absence of VUR, asymptomatic bacteriuria in patients undergoing CIC is not a significant risk factor for scarring and does not require antibiotic therapy.

Adult↗
PubMed1995

Outcome analysis of pediatric pyeloplasty as a function of patient age, presentation and differential renal function.

PURPOSE: We retrospectively reviewed a consecutive series of patients who underwent pyeloplasty. In all cases preoperative and postoperative isotope renal scans were performed to assess the surgical outcome with particular emphasis on the change in renal function postoperatively. MATERIALS AND METHODS: The clinical records of 108 consecutive children with ureteropelvic junction obstruction were reviewed. Individual renal function was evaluated and obstruction was confirmed by diuretic assisted 99mtechnetium diethylenetriaminepentaacetic acid or mercaptoacetyltriglycine renography. A total of 100 pyeloplasties in 98 children between 5 days and 16 years old was included. Results were analyzed by groups according to patient age and symptoms at presentation. RESULTS: Drainage half-times improved in 98% of patients and only 1 required reoperation. Improved renal function greater than 5% was noted in about a third of each age group. Function remained stable in 68% of the kidneys and decreased in only 1. Of the improved kidneys 77% had impaired function preoperatively (40% or less of the total contribution). Those presenting with a renal mass had the greatest improvement in function. There was no statistically significant difference in improvement in renal function by age group or patient presentation. Regression analysis revealed that preoperative differential renal function was the only statistically significant predictor of improvement in renal function after pyeloplasty. CONCLUSIONS: Pyeloplasty in children is safe and renal functional improvement can be expected in the majority of kidneys with impaired function at presentation. However, there was no indication that early pyeloplasty in infants is more likely to result in improved function than in older children.

Adolescent↗
PubMed1994

Blunt renal trauma in children: healing of renal injuries and recommendations for imaging follow-up.

Initial CT grading of renal injury was correlated with the frequency of complications and the time course of healing in 35 children. All renal contusions (grade 1, 8) and small parenchymal lacerations (grade 2, 8) healed without complications. All lacerations extending to the collecting system (grade 3, 9) resulted in mild to severe loss of renal function with progressive healing over 4 months. One of four segmental infarcts (grade 4A), and five of six vascular pedicle injuries (grade 4B) resulted in severe loss of renal function. Complications, including urinoma (2), sepsis (1), hydronephrosis (1), and persistent hypertension (2), were limited to grade 3 and 4 injuries. Our results suggest that mild renal injuries do not require follow-up imaging. Major renal lacerations and vascular pedicle injuries, however, often result in loss of renal function and should be followed up closely due to the risk of delayed complications. Follow-up examinations should continue for 3-4 months until healing is documented.

Adolescent↗
PubMed1994

Association of Lewis blood group phenotypes with urinary tract infection in children.

Many blood group antigens, genetically controlled carbohydrate molecules, are found on the surface of uroepithelial cells and may affect bacterial adherence and increase the frequency of urinary tract infection (UTI) in adults. Sixty-two children aged 2 weeks to 17 years (mean, 2.3 years) who were hospitalized with fever in association with UTIs caused by Escherichia coli had complete (n = 50) or partial (n = 12) erythrocyte antigen typing to determine the role of erythrocyte antigens and phenotypes in UTI in children; 62 healthy children undergoing nonurologic elective surgery, matched 1 to 1 for age, sex, and race to the patient group, formed the control group. In univariate tests, patients and control subjects did not differ in ABO, Rh, P, Kell, Duffy, MNSs, and Kidd systems by the McNemar test of symmetry (p > 0.05). The frequency of the Lewis (Le) (a-b-) phenotype was higher (16/50 vs 5/50; p = 0.0076) and the frequency of the Le(a + b +) phenotype was lower (8/50 vs 16/50; p = 0.0455) in the patient population than in the control subjects. A stepwise logistic regression model to predict UTI with the explanatory variables A, B, O, M, N, S, s, Pl, Lea, and Leb showed that only the Lea and Leb antigens entered the model with p < 0.1. The Le(a-b-) phenotype was associated with UTI in this pediatric population. The relative risk of UTI in children with the Le(a-b-) phenotype was 3.2 (95% confidence interval, 1.3 to 7.9). Specific blood group phenotypes in pediatric populations may provide a means to identify children at risk of having UTI.

Adolescent↗
PubMed1994

Pediatric pyeloplasty: is routine retrograde pyelography necessary?

To evaluate the necessity for retrograde pyelography in the preoperative evaluation of children undergoing pyeloplasty, we reviewed the records of 108 consecutive patients (age range 5 days to 18 years, median 1 year) who underwent pyeloplasty at our institution during a 6-year period. The routine preoperative evaluation consisted of a renal/bladder sonogram, furosemide renal scan (99mtechnetium-diethylenetriaminepentaacetic acid or 99mtechnetium-mercaptoacetyltriglycine) and voiding cystogram. No other imaging studies were obtained in 95 patients (88%). Other upper tract studies usually performed before referral included excretory urography in 9 cases and computerized tomography in 5. Preoperative retrograde pyelography was only performed in 1 symptomatic patient before referral to our institution. Surgical findings confirmed obstruction at the ureteropelvic junction in all patients. Undetected ureteral dilatation, which might suggest undiagnosed distal obstruction, was not encountered. After pyeloplasty 2 patients were lost to followup, renal drainage improved in 104 (98%) and drainage failed to improve in 2 of whom 1 (0.9%) required reoperation. All patients who presented with symptomatic uretero-pelvic junction obstruction experienced postoperative resolution of the presenting complaints. Our series demonstrates that routine retrograde pyelography to define the level of obstruction is not necessary for successful primary pyeloplasty. In experienced hands and with careful attention to detail, the combination of renal/bladder sonography and diuretic renography can reliably exclude the possibility of distal obstruction in children with hydronephrosis before pyeloplasty.

Adolescent↗
PubMed1994

Urinary N-acetyl-beta-glucosaminidase and beta-2-microglobulin in the diagnosis of urinary tract infection in febrile infants.

Urinary N-acetyl-beta-glucosaminidase (NAG) and beta-2-microglobulin (B2M) concentrations were measured in 24 pediatric patients with febrile urinary tract infection (UTI) and compared with the technetium-99m-labeled dimercaptosuccinic acid (DMSA) renal scan results, in order to evaluate a noninvasive means to localize the site of UTI. Increased urinary B2M and NAG were not associated with renal inflammation (pyelonephritis), as defined by positive dimercaptosuccinic acid scan. Median NAG concentrations were 114.2 mumol/hour/mg creatinine (CR) (range, 5.7 to 305.4) in 17 febrile UTI patients vs. 13.8 (range, 3.4 to 104.3) in 17 age and sex-matched febrile controls with negative urine cultures, P = 0.0001. The sensitivity and specificity of NAG > or = 40 mumol/hour/mg of CR in predicting UTI in febrile patients, regardless of the site of infection, were 88 and 88%, respectively. Increased urinary NAG is associated with UTI in febrile patients regardless of the level of infection (scan status), and may be an informative indicator of UTI.

Acetylglucosaminidase↗
PubMed1994

The value of urinalysis in differentiating acute pyelonephritis from lower urinary tract infection in febrile infants.

There is an ongoing debate on the best way to screen febrile infants for urinary tract infection. We examined the urinanalysis (UA) findings on admission among infants less than 16 weeks old, with and without acute pyelonephritis (APN), as defined by the dimercaptosuccinic acid (DMSA) renal scan findings, performed during a 57-month period. Forty-nine cases with a positive DMSA scan were compared with 79 negative study cases. A negative UA for leukocytes (< 5 white blood cells/high power field) was found in 4 of 49 (8.1%) cases with APN by DMSA, and in 34 of 79 (43%) cases with a negative DMSA (odds ratio 10.88 (95% confidence interval, 2.31 to 70.3; P < 0.001)). Three of the 4 infants not suspected to have APN by their UA findings would have been admitted for a full sepsis workup based on their clinical presentation and/or their laboratory findings on admission. We conclude that a fresh UA may be a sufficient screening method for the exclusion of APN in infants assessed for fever of no obvious origin.

Acute Disease↗
PubMed1993

Mineral balance and bone turnover in adolescents with anorexia nervosa.

We evaluated seven female adolescents with anorexia nervosa to determine whether calcium metabolism was affected by their disorder. We measured calcium absorption, urinary calcium excretion, and calcium kinetics, using a dual-tracer, stable-isotope technique during the first weeks of an inpatient nutritional rehabilitation program. Results were compared with those from a control group of seven healthy adolescent girls of similar ages. The percentage of absorption of calcium was lower in subjects with anorexia nervosa than in control subjects (16.2% +/- 6.3% vs 24.6% +/- 7.2%; p < 0.05). Urinary calcium excretion was greater in subjects with anorexia nervosa than in control subjects (6.4 +/- 2.5 vs 1.6 +/- 0.7 mg.kg-1 x day-1; p < 0.01) and was associated with bone resorption rather than calcium hyper-absorption. Calcium kinetic studies demonstrated a decreased rate of bone formation and an increased rate of bone resorption. These results suggest marked abnormalities in mineral metabolism in patients with anorexia nervosa. From these results, we hypothesize that improvement in bone mineralization during recovery from anorexia nervosa will require resolution of hormonal abnormalities, including hypercortisolism, in addition to increased calcium intake.

Absorption↗
PubMed1993

Diuretic renography in the evaluation of neonatal hydronephrosis: is it reliable?

Arguments against the use of diuretic renography in the assessment of newborn hydronephrosis include immature function of neonatal kidneys, previously reported poor diuretic response and nonreproducible drainage patterns. To address these concerns we reviewed the initial and followup renal scans of 17 neonates with hydronephrosis without ureterectasis diagnosed by perinatal ultrasonography. All patients were evaluated with an initial diuretic renal scan up to the age of 28 days, and all had normal cystograms. A total of 19 dilated kidneys was studied of which 13 ultimately required pyeloplasty and 6 were managed nonsurgically. Patient study parameters included age and weight at the time of each renal scan, side of hydronephrosis, differential function of each kidney, pre-diuretic and post-diuretic urine output, and drainage half-time of each kidney. The diuretic renal scans followed a standardized protocol. There was no statistically significant difference between neonatal and followup differential function (p > 0.05), and the correlation coefficient was highly significant (r = 0.968). Comparison of response to diuretic stimulation (ml./kg. per minute) revealed no statistically significant difference as the patients aged with brisk urine output 3 to 5 times greater than previously reported. The distribution and mean drainage half-times for normal nonhydronephrotic kidneys were similar when comparing those performed as neonates and at followup. Hydronephrotic kidneys managed nonsurgically maintained almost identical patterns. Those repaired surgically demonstrated appropriate improvement in drainage but function remained unchanged. These results refute each of the criticisms against the use of diuretic renography to evaluate neonatal hydronephrosis and demonstrate its reliability in neonates.

Furosemide↗
PubMed1992

Renal cortical scintigraphy in the diagnosis of acute pyelonephritis.

Comparative clinical studies have shown renal cortical scintigraphy, using technetium-99m (99mTc)-labeled glucoheptonate or dimercaptosuccinic acid (DMSA), to be significantly more sensitive than either intravenous pyelography or renal sonography in the diagnosis of acute pyelonephritis. However, due to uncertainties about the diagnostic accuracy of the clinical and laboratory parameters used in these studies, true sensitivity of renal cortical scintigraphy was unknown. Therefore, we evaluated the accuracy of [99mTc]DMSA scintigraphy in the diagnosis of experimentally induced acute pyelonephritis in piglets using strict histopathologic criteria as the standard of reference. The sensitivity and specificity of the DMSA scan for the diagnosis of acute pyelonephritis were 91% and 99%, respectively, with an overall 97% agreement between the scintigraphic and histopathologic findings. Based on the results of this experimental study, we used the [99mTc]DMSA scan as the standard of reference for the diagnosis of acute pyelonephritis, and conducted a prospective clinical study of 94 children hospitalized with the diagnosis of acute febrile urinary tract infection (UTI). The aims of this study were (1) to determine the relationship among vesicoureteral reflux, P-fimbriated Escherichia coli, acute pyelonephritis, and renal scarring, and (2) to evaluate the diagnostic reliability of the clinical and laboratory parameters commonly used in the diagnosis of acute pyelonephritis. We documented acute pyelonephritis in 62 (66%) of 94 patients. Vesicoureteral reflux was demonstrated in 29 (31%) of the total group and in only 23 (37%) of 62 patients with acute pyelonephritis. The prevalence of P-fimbriae in the E coli isolates was 64% in the patients with acute pyelonephritis and 78% in those with a normal DMSA scan. Even in patients without reflux, P-fimbriae were found in 71% of isolates from the patients with acute pyelonephritis and in 75% of those with a normal renal scan. Follow-up DMSA scans were obtained in 33 patients with acute pyelonephritis in 38 kidneys. We found complete resolution of the acute inflammatory changes in 58% of the involved kidneys and renal scarring in the remaining 42%, including 40% of the kidneys associated with reflux and 43% of those without reflux.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1992

Pyelonephritis in male infants: how important is the foreskin?

We investigated the association of the uncircumcised foreskin and pyelonephritis in male infants less than 6 months old. During a 21-month prospective study 94 children (age range 2 weeks to 18.9 years) were hospitalized for febrile urinary tract infection. The male-to-female ratio for 35 patients less than 6 months old was 2.2:1. Of 59 patients older than 6 months the male-to-female ratio was reversed at 0.25:1 (p less than 0.001). In 13 of 24 infants (54%) less than 6 months old and in 8 of 12 boys (67%) older than 6 months a dimercaptosuccinic acid renal scan documented acute parenchymal damage (p = 0.72). Vesicoureteral reflux or other genitourinary abnormalities were found in only 3 of 24 patients (12.5%) less than 6 months old compared with 6 of 12 boys (50%) older than 6 months (p = 0.036). Of 24 infants less than 6 months old 22 (92%) were uncircumcised compared with 6 of 12 boys (50%) older than 6 months (p = 0.009). We then retrospectively compared the circumcision status of the infants who had febrile urinary tract infection with a control group of 63 infants matched for age, race and socioeconomic status hospitalized with febrile upper respiratory infection during a similar period. The frequency of uncircumcised infants in the control group with febrile upper respiratory infection was only 44% (28 of 63) compared with 91% of infants with febrile urinary tract infection (p less than 0.001). Overall the findings of the male predominance among patients less than 6 months old with febrile urinary tract infection, the disproportionately high frequency of infants with febrile urinary tract infection who were not circumcised, and the disproportionately low occurrence of vesicoureteral reflux and other genitourinary abnormalities in infants with febrile urinary tract infection strongly support an association between circumcision status and the risk for febrile urinary tract infection and pyelonephritis in male infants.

Acute Disease↗