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Michael Kaplan

Publications and source records attributed to Michael Kaplan.

36 records · Page 2Linked to original sources

Understanding and preventing severe neonatal hyperbilirubinemia: is bilirubin neurotoxity really a concern in the developed world?

Although rare, extreme neonatal hyperbilirubinemia and its dreaded complication, kernicterus, continue to occur. Hyperbilirubinemia develops when bilirubin production exceeds the body's capacity to excrete it, primarily by conjugation. Genetic, environmental, and racial factors affecting the equilibrium between these processes are discussed. Adjuncts to the interpretation of the serum total bilirubin concentration are suggested. Prevention and management of severe hyperbilirubinemia should be based on American Academy of Pediatrics guidelines, with individualization including earlier institution of treatment and delayed discharge from the hospital for neonates with risk factors for kernicterus.

Bilirubin↗

Glucose-6-phosphate dehydrogenase deficiency: a hidden risk for kernicterus.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, a commonly occurring enzymatic defect, is an important risk factor in the pathogenesis of severe neonatal hyperbilirubinemia. Many of the recently reported cases of kernicterus, even in countries with a low overall incidence of the G-6-PD deficiency such as the United States and Canada, have been found to be enzyme deficient. In many cases the hyperbilirubinemia may be due to acute hemolysis precipitated by exposure to an identifiable chemical trigger, or to infection. In other cases the hemolysis may be mild, the hyperbilirubinemia being due to diminished bilirubin conjugation. An interaction between G-6-PD deficiency and promoter polymorphism for the gene encoding the bilirubin conjugating enzyme, UDP-glucuronosyltranferase 1A1, associated with Gilbert syndrome, has been implicated in the pathogenesis of hyperbilirubinemia. Neonates whose families originated in areas at high risk for G-6-PD deficiency should be vigilantly observed for jaundice. Phototherapy is the mainstay of treatment, with exchange transfusion being performed in those unresponsive to phototherapy. A high degree of physician awareness is essential in the identification and follow-up of these high-risk neonates.

Glucosephosphate Dehydrogenase Deficiency↗

Hyperbilirubinemia among African American, glucose-6-phosphate dehydrogenase-deficient neonates.

BACKGROUND: Although glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is prevalent in African Americans, their risk of associated neonatal hyperbilirubinemia has not been prospectively studied. OBJECTIVE: To compare hemolysis and the risk of hyperbilirubinemia among African American, G-6-PD-deficient neonates (study group) and G-6-PD-normal control subjects. METHODS: Consecutive, healthy, term and near-term, male neonates born to African American mothers comprised the patient cohort. G-6-PD testing was performed with umbilical cord blood samples. Routine management included measurement of the end tidal carbon monoxide level corrected for ambient carbon monoxide level (ETCOc) within 4 hours after delivery (assessment of hemolysis), > or =1 predischarge bilirubin determination, and additional bilirubin testing as clinically indicated. Indications for phototherapy were identical for study patients and control subjects. Neonates were monitored for the first 1 week of life. ETCOc results, the incidence of hyperbilirubinemia (defined as a transcutaneous or plasma total bilirubin concentration of > or =95th percentile for the hour of life), and the need for phototherapy were compared between the G-6-PD-deficient and G-6-PD-normal groups. RESULTS: Five hundred male patients were enrolled, of whom 64 (12.8%) were G-6-PD-deficient. ETCOc values (median and interquartile range) were higher among G-6-PD-deficient neonates than among control neonates (2.4 ppm [2.0-2.9 ppm] vs 2.1 ppm [1.7-2.5 ppm]). More G-6-PD-deficient neonates developed hyperbilirubinemia than did control subjects (14 of 64, 21.9%, vs 29 of 436, 6.7%; relative risk: 3.27; 95% confidence interval: 1.83-5.86), whereas 13 (20.3%) met the criteria for phototherapy, compared with 25 control subjects (5.7%) (relative risk: 3.53; 95% confidence interval: 1.91-6.56). No cases of kernicterus were observed. CONCLUSIONS: Within the African American neonatal population, there is a subgroup of G-6-PD-deficient infants with elevated rates of hemolysis, a higher incidence of hyperbilirubinemia, and a greater requirement for phototherapy, compared with G-6-PD-normal control subjects. These newborns should be monitored vigilantly for the development of hyperbilirubinemia.

Bilirubin↗

Comparison of treatment plans using intensity-modulated radiotherapy and three-dimensional conformal radiotherapy for paranasal sinus carcinoma.

PURPOSE: To compare intensity-modulated radiotherapy (IMRT) treatment planning with three-dimensional conformal radiotherapy (3D-CRT) planning for paranasal sinus carcinoma. MATERIALS AND METHODS: Treatment plans using traditional 3-field technique, 3D-CRT planning, and inverse planning IMRT were developed for a case of paranasal sinus cancer requiring adjuvant radiotherapy. Plans were compared with respect to dose conformality, dose-volume histograms, doses to critical normal tissues, and ease of treatment delivery. RESULTS: The inverse-planned IMRT technique was more conformal around the tumor target volume than conventional techniques. The dose-volume histograms demonstrated significantly better critical normal-tissue sparing with the IMRT plans, while able to deliver a minimum dose of 60 Gy to the clinical tumor volume and 70 Gy to the gross tumor volume. Acute toxicities in our analysis were minimal. CONCLUSIONS: IMRT planning provided improved tumor target coverage when compared to 3D-CRT treatment planning. There was significant sparing of optic structures and other normal tissues, including the brainstem. Inverse planning IMRT provided the best treatment for all paranasal sinus carcinomas, but required stringent immobilization criteria. Further studies are needed to establish the true clinical advantage of this modality.

Aged↗

Somatic growth of preterm infants during skin-to-skin care versus traditional holding: a randomized, controlled trial.

We performed this randomized trial to determine whether infants receiving skin-to-skin care (SSC) grew more rapidly and had a shorter duration of hospital stay compared with infants held by their parents in a traditional way. Infants who met eligibility criteria (<or=32 wk of gestation, <or=1500 g, minimal ventilatory support, and hemodynamically stable) were randomized to traditional holding (TH) or SSC groups. Parents in both groups were allowed to hold infants for a total of 8 hours per day (periods of up to 4 hr, twice/d). During the study, infants in the TH group were held 4.8 +/- 3.5 times per week and 76 +/- 39 minutes per day, and infants in the SSC group were held 4.0 +/- 2.8 times per week and 79 +/- 40 minutes per day. No significant differences were observed in weight accretion or linear growth. However, exposure to SSC was associated with greater head growth, even after controlling for head circumference at birth (p =.03). SSC may increase the likelihood of successful breastfeeding.

Breast Feeding↗

Hemolysis and bilirubin conjugation in association with UDP-glucuronosyltransferase 1A1 promoter polymorphism.

Hemolysis may contribute to hyperbilirubinemia in Gilbert's syndrome. The authors examined blood carboxyhemoglobin corrected for inspired CO (COHbc) to index heme catabolism and serum conjugated bilirubin fractions to reflect bilirubin conjugation. Both parameters were related to UDP-glucuronosyltransferase 1A1 (UGT) promoter polymorphism, associated with Gilbert's syndrome, in term male newborns. COHbc was expressed as percentage of total hemoglobin, and total conjugated bilirubin (TCB) value as a percentage of serum total bilirubin (STB), (TCB/STB[%]). A production/conjugation index, COHbc/(TCB/STB[%]), represented bilirubin production divided by conjugation. UGT promoter genotype was designated according to the number of promoter TA insertions in each allele: 6/6, homozygous normal; 6/7, heterozygous; 7/7, homozygous variant. STB and COHbc values were higher in the 7/7 subgroup than the other counterparts (P <.01). The COHbc/(TCB/STB[%]) was higher in the 7/7 than either the 6/6 or 6/7 subsets (1.93 [1.31-2.88] vs. 0.85 [0.51-1.72] and 0.84 [0.53-1.87], respectively; P <.01). In conclusion, 7/7 UGT promoter polymorphism was associated with increased blood COHbc values (unexpected finding) as well as diminished serum total conjugated bilirubin ratios (expected finding). The increased hemolysis may contribute to the pathogenesis of increased STB values seen in Gilbert's syndrome, and exacerbate neonatal hyperbilirubinemia associated with the promoter polymorphism.

Bilirubin↗

Glucose-6-phosphate dehydrogenase deficiency: a potential source of severe neonatal hyperbilirubinaemia and kernicterus.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is a commonly occurring enzyme defect that can lead to severe neonatal hyperbilirubinaemia and kernicterus. Both increased haemolysis, sometimes due to an identifiable chemical trigger or to infection, and diminished bilirubin conjugation, the result of an interaction between G-6-PD deficiency and Gilbert's syndrome, contribute to the pathogenesis of the jaundice. Phototherapy is the mainstay of treatment, with exchange transfusion held in reserve for those neonates who do not respond to phototherapy. Pharmacological agents such as Sn-mesoporphyrins, which prevent bilirubin production by inhibiting the enzyme heme oxygenase, can limit hyperbilirubinaemia and possibly prevent the need for exchange transfusion. Predischarge serum total bilirubin screening is useful in predicting which neonates are at high risk for developing hyperbilirubinaemia. Migration patterns make G-6-PD deficiency a condition which may nowadays be encountered in virtually any corner of the globe and a high degree of physician awareness is essential.

Bilirubin↗

Imbalance between production and conjugation of bilirubin: a fundamental concept in the mechanism of neonatal jaundice.

OBJECTIVE: The objective of this study was to evaluate the roles of production and conjugation of bilirubin, individually and in combination, in the mechanism of neonatal jaundice. METHODS: A cohort of healthy, term male newborns was sampled on the third day of life, coincident with routine metabolic screening, for blood carboxyhemoglobin determination, a reflection of heme catabolism, and for serum unconjugated and conjugated bilirubin fractions, reflecting bilirubin conjugation. The former was determined by gas chromatography, corrected for inspired CO (COHbc), and expressed as percentage of total hemoglobin. Serum bilirubin fractions were quantified by alkaline methanolysis and reverse phase high performance liquid chromatography. The sum of all bilirubin fractions comprised serum total bilirubin (STB). Total conjugated bilirubin (TCB) was comprised of the sum of the conjugated fractions and was expressed as percentage of STB (TCB[%]). A "bilirubin production/conjugation index" (COHbc/[TCB(%)] represented the combined roles of these modalities in the mechanism of bilirubinemia. Relationships between STB concentrations on the one hand, and COHbc values, TCB(%) proportions, and the production/conjugation index on the other, were determined by applying a best-fit regression analysis methodology. RESULTS: Mean (+/- standard deviation) STB concentration at the time of sampling was 114 +/- 48 micro mol/L (range: 8-263 micro mol/L). Mean COHbc value was 0.77 +/- 0.19%, and median (interquartile range) TCB(%) was 0.737 (0.465-1.260)%. COHbc values correlated directly with STB concentrations (r = 0.38; s = 46.1), and TCB(%) correlated inversely with STB (r = 0.40; s = 45.8). The production/conjugation index correlated positively with STB values (r = 0.61; s = 45.8), the r value for the index being higher than that of either COHbc or TCB(%), individually. The bilirubin production/conjugation index seemed to have a biphasic relationship to STB: STB values rose steeply in concert with increasing index values in the lower range of the index, and subsequently plateaued in the higher range of the index. CONCLUSIONS: Within the range of STB concentrations encountered, both increasing bilirubin production and diminishing bilirubin conjugation contributed to STB. The production/conjugation index confirmed that imbalance between production and conjugation of bilirubin plays an important role in the mechanism of neonatal bilirubinemia. alkaline methanolysis, bilirubin, bilirubin conjugation, carbon monoxide, carboxyhemoglobin, gas chromatography, hemolysis, high performance liquid chromatography, physiologic jaundice.

Bilirubin↗

Anterior cruciate ligament replacement: comparison of bone-patellar tendon-bone grafts with two-strand hamstring grafts. A prospective, randomized study.

BACKGROUND: The purpose of this investigation was to evaluate replacement of a torn anterior cruciate ligament with either a bone-patellar tendon-bone autograft or a two-strand semitendinosus-gracilis autograft to compare the results of clinical testing, patient satisfaction, activity level, functional status, and muscle strength. METHODS: Fifty-six patients with a torn anterior cruciate ligament were enrolled in a prospective, randomized, controlled study. Twenty-eight underwent reconstruction with a bone-patellar tendon-bone autograft, and twenty-eight were treated with a two-strand semitendinosus-gracilis autograft. Patients were followed for an average of thirty-nine months (range, thirty-six to fifty-seven months). At the time of final follow-up, twenty-two patients in each group were evaluated in terms of clinical test findings, patient satisfaction, activity level, functional status, and isokinetic muscle strength. RESULTS: The objective outcome of replacement of the torn anterior cruciate ligament with a bone-patellar tendon-bone graft was superior to that obtained with a two-strand semitendinosus-gracilis graft. At the three-year follow-up interval, the patients in whom a hamstring graft had been used had an average of 4.4 mm of increased anterior knee laxity compared with the laxity of the contralateral, normal knee, whereas the patients in whom a bone-patellar tendon-bone graft had been used had an average of 1.1 mm of increased knee laxity. Fourteen percent (three) of the twenty-two patients with a hamstring graft had a mild pivot shift, and 27% (six) had a moderate pivot shift. Only 14% (three) of the twenty-two patients with a bone-patellar tendon-bone graft had a mild pivot shift, and none had a moderate pivot shift. At the same follow-up interval, the patients in whom a hamstring graft had been used had significantly lower peak knee-flexion strength than those who had a bone-patellar tendon-bone graft (p = 0.039). In contrast, the two treatments produced similar outcomes in terms of patient satisfaction, activity level, and knee function (ability to perform a one-legged hop, bear weight, squat, climb stairs, run in place, and duckwalk). CONCLUSIONS: After three years of follow-up, the objective results of anterior cruciate ligament replacement with a bone-patellar tendon-bone autograft were superior to those of replacement with a two-strand semitendinosus-gracilis graft with regard to knee laxity, pivot-shift grade, and strength of the knee flexor muscles. However, the two groups had comparable results in terms of patient satisfaction, activity level, and knee function.

Adolescent↗

Hemolysis and hyperbilirubinemia in an African American neonate heterozygous for glucose-6-phosphate dehydrogenase deficiency.

Despite recent case reports of bilirubin encephalopathy in African American glucose-6-phosphate dehydrogenase (G6PD)-deficient neonates, there is a misconception that, in African Americans, G6PD deficiency need not be considered in the differential diagnosis of hyperbilirubinemia. We present a case of a hyperbilirubinemic African American female neonate in whom coexisting G6PD deficiency in the heterozygous state, and Gilbert's syndrome, were confirmed by DNA analysis. Hemolysis, predictive of the subsequent icterus, was documented by end-tidal carbon monoxide determinations at two time periods within the first 25 hours of life. A diagnosis of G6PD deficiency should be considered in African American neonates, females as well as males, with unexplained hemolysis or hyperbilirubinemia.

Black People↗

Expectant management of midtrimester premature rupture of membranes: a plea for limits.

OBJECTIVE: Our aim was to assess neonatal and maternal complications of the expectant management of pregnancies with preterm premature rupture of membranes (P-PROM) prior to 24 weeks of gestation and to delineate a patient consult strategy. STUDY DESIGN: We included all consecutive cases of early midtrimester P-PROM (16-24 weeks gestation). Information coded in our perinatal database was analyzed. Descriptive statistics, Student's t-test and Mann-Whitney test, and a logistic regression model were built accordingly. RESULTS: A total of 28 women presented with P-PROM at 16-24 weeks (mean 22.7+/-1.0 weeks). Two patients declined conservative management and one was lost to follow-up (10.7%). In all, 25 (89.2%) were followed until the onset of labor or development of chorioamnionitis. Overall, 8/25 (32%) Of the neonates survived. Pulmonary hypoplasia accounted for three deaths (3/25, 12%). Of 10 pregnancies with P-PROM before 22 weeks gestation, two (20%) neonates survived. The amount of amniotic fluid and gestational age at the time of diagnosis were crucial independent factors determining overall survival. Pulmonary hypoplasia (12%) and skeletal deformities (0%) were infrequent. The 21-day mean maternal antenatal hospital stay was further complicated by a high cesarean rate delivery (33.7%) and by postpartum infectious morbidity (32%). CONCLUSION: In cases of early midtrimester P-PROM (<24 weeks) expectantly managed, neonatal survival is positively associated with the amount of amniotic fluid present and with the gestational age at the time of diagnosis. The mothers are at increased risk of prolonged antenatal hospitalization, cesarean delivery, preterm birth, and postpartum infection. In very early midtrimester P-PROM (<22 weeks), the maternal complication rate outweighs the poor neonatal outcome and expectant management should be reconsidered.

Adult↗

Is there a causal link between maltreatment and adolescent pregnancy? A literature review.

CONTEXT: Despite a sizable amount of research addressing the relationship between violence and women's reproductive health, it has not been shown whether there is sufficient evidence of a causal link between childhood maltreatment and subsequent adolescent pregnancy. METHODS: Three databases (Medline, PsychiNFO and SocioFile) were searched for studies published between 1980 and 2000 relating maltreatment and adolescent pregnancy. The review was limited to empirical studies; theoretical articles and those with no women who were aged 21 or younger during the research period or when they experienced maltreatment were excluded. RESULTS: Fifteen articles on the topic were found All were published after 1989; all but one were cross-sectional, were retrospective and relied on recall. All of the studies dealt with sexual maltreatment, either alone or in combination with other types of maltreatment; few covered emotional abuse or neglect. The studies lacked consistent definitions of the various types of maltreatment. Only one examined adolescent mothers' relationships with men, and none examined relationships with perpetrators. Few dealt with racial and ethnic differences related to violence. All lacked a specific theoretical approach. Ten of the studies supported a link between maltreatment and adolescent pregnancy, and five eitherdid not support a link or qualified the relationship. Substance abuse, poor mental health and promiscuity were among the mediating variables examined. CONCLUSIONS: Because recent studies have reached conflicting findings, had methodological weaknesses and lacked theoretical grounding, whether a causal link exists between maltreatment and adolescent pregnancy remains an unanswered question.

Adolescent↗