PubMed Health⌕ Search

Biomedical subjects

N Okun

Publications and source records attributed to N Okun.

12 recordsLinked to original sources
PubMed2003

Is maternal obesity a predictor of shoulder dystocia?

OBJECTIVE: To explore the relationship between maternal obesity and shoulder dystocia while controlling for the potential confounding effects of other variables associated with obesity. METHODS: We performed a case-control study of provincial delivery records audited by the Northern and Central Alberta Perinatal Outreach Program. Risk factors evaluated were selected based on previously published studies. Cases and controls were drawn from 45,877 live singleton cephalic vaginal deliveries weighing more than 2500 g between January 1995 and December 1997. There were 413 cases of shoulder dystocia (0.9% incidence). Controls (n = 845) were randomly chosen from the remainder of the target population to create a 1:2 case/control ratio. Univariate analysis with calculation of odds ratios (ORs) was used to determine which of the chosen risk factors were significantly related to the incidence of shoulder dystocia. Multivariable regression analyses were then used to determine the independently associated variables, and the adjusted ORs were obtained for each relevant risk factor. RESULTS: Maternal obesity was not significant as an independent risk factor for shoulder dystocia after adjusting for confounding variables (adjusted OR 0.9; 95% confidence interval [CI] 0.5, 1.6). Fetal macrosomia was the single most powerful predictor. The adjusted ORs were 39.5 (95% CI 19.1, 81.4) for birth weight greater than 4500 g and 9.0 (95% CI 6.5, 12.6) for birth weight between 4000 and 4499 g. CONCLUSION: The strongest predictors of shoulder dystocia are related to fetal macrosomia. For obese nondiabetic women carrying fetuses whose weights are estimated to be within normal limits, there is no increased risk of shoulder dystocia.

Comorbidity↗
PubMed2001

Asymmetric sandwich-type polyoxoanions. Synthesis, characterization, and x-ray crystal structures of diferric complexes [TM(II)Fe(III)(2)(P(2)W(15)O(56))(P(2)TM(II)(2)W(13)O(52))](16-), TM = Cu or Co.

Reaction of the diferric sandwich-type polyoxometalate (NaOH(2))(2)Fe(III)(2)(P(2)W(15)O(56))(2)(16-)(1) with excess aqueous Cu(II) or Co(II) yields a new type of d-electron-metal substituted polyoxometalate, [TM(II)Fe(III)(2)(P(2)W(15)O(56)) (P(2)TM(II)(2)W(13)O(52))](16-), TM = Cu (2), Co (3), respectively. The structure of the sodium salt of 2 (Na2), determined by single-crystal X-ray diffraction analysis (a = 13.4413(9) A, b = 21.2590(15) A, c = 25.5207(18) A, alpha = 80.475(2) degrees, beta = 85.555(2) degrees, gamma = 89.563(2) degrees, triclinic, P(-)1, R1 = 5.42%, based on 43097 independent reflections), consists of a defect Fe(2)Cu central unit sandwiched between two different trivacant Wells-Dawson-type units, P(2)W(15) and P(2)Cu(2)W(13), where the latter unit has two octahedral Cu(II) ions substituted for two adjacent belt W(VI) atoms. The CuO(5)OH(2) octahedron in the central unit shows pronounced Jahn-Teller distortion. A low-resolution X-ray structure of Na3 is included in the Supporting Information. UV-visible, infrared, (31)P NMR, cyclic voltammetric, and elemental analysis data are all consistent with the structure determined from the X-ray analysis. Cyclic voltammograms of 2 and 3 exhibit multiple electron-transfer processes under ambient conditions, and copper or cobalt incorporation into the framework of 1 results in a substantial pertubation of the electrochemical properties of the polyoxotungstate framework. The tetra-n-butylammonium salts of 2 and 3 (readily prepared by metathesis) are stable and effective catalysts for the oxidation of some alkenes with high yields based on H(2)O(2).

Journal Article↗
PubMed1999

Polytopic anomalies with agenesis of the lower vertebral column.

We describe clinical, pathological and radiological findings in 15 cases of sporadic and familial lower spine agenesis with additional anomalies of the axial skeleton and internal organs and speculate about the cause and pathogenesis of this malformation complex. We show that all of these findings are defects of blastogenesis, originate in the primary developmental field and/or the progenitor fields, thus representing polytopic field defects. This concept appears applicable in our cases and makes such terms such as "caudal regression syndrome" or "axial mesodermal dysplasia spectrum" redundant.

Abnormalities, Multiple↗
PubMed1999

Technical factors in early amniocentesis predict adverse outcome. Results of the Canadian Early (EA) versus Mid-trimester (MA) Amniocentesis Trial.

The purpose of this study was to identify risk factors for fetal loss and other pregnancy complications associated with genetic amniocentesis. Data were acquired in the Canadian Early Amniocentesis Trial (CEMAT), a multicentered (12) prospective, randomized trial comparing continuous ultrasound-guided early amniocentesis (EA) and mid-trimester amniocentesis (MA) (CEMAT Group, 1998). Details of the procedure were recorded and analysed by allocation (EA versus MA), operator and centre, and correlated with pregnancy outcome. A total of 62 spontaneous pregnancy losses occurred between the procedure and 20 weeks' gestation among the 3691 patients who received their procedures within the allocated window (EA=53/1916, MA=9/1775). Technical factors correlating with these losses included procedures 'judged to be difficult' by the operator, and post-procedure amniotic fluid leakage or bleeding. Maternal risk factors included maternal hypertension (fetal loss 11. 1 per cent, compared with non-hypertensive women, 2.6 per cent) increased body mass index (BMI) and gravidity of three or greater. Allocation to EA was predictive of fetal loss, as well as failed procedure, multiple needle insertions, amniotic fluid leakage, failed culture and talipes equinovarus, in excess compared with MA. In conclusion, in this large prospective randomized trial evaluating amniocentesis, specific maternal, fetal and procedural variables were found to be predictive of fetal loss and adverse pregnancy outcome. Performing amniocentesis before 13 weeks' gestation (EA) was the major predictive factor for adverse outcome. These data suggest that first-trimester chorionic villus sampling (CVS) and MA will likely remain the invasive procedures of choice for evaluation of fetal karyotype.

Abortion, Spontaneous↗
PubMed1998

Pregnancy in chronic dialysis: a review and analysis of the literature.

UNLABELLED: Pregnancy is uncommon in end-stage renal failure, particularly in patients requiring dialysis. We reviewed the literature from 1965 to date, seeking an optimal way of dialyzing pregnant women after encountering one such patient METHODS: We searched the English literature by cross-referencing "pregnancy" with "hemo-" or "peritoneal dialysis" and "renal failure". Eighty-six pregnancies worldwide were found to which we added one case of our own. Various independent factors were studied against gestational age at delivery using uni- and multivariate analysis. These factors included mother's age, previous delivery, diagnoses of renal disease, dialysis duration prior to pregnancy, gestational age at onset of dialysis, dialysis type, level of hemoglobin during pregnancy, BUN and creatinine targets, BUN/creatinine ratio, dialysis intensity at the beginning and end of pregnancy, influence of erythropoietin and dialysis complications. RESULTS: Of the 87 pregnancies, 12% resulted in stillbirths, 9% of neonates died prior to discharge. The mean gestational age at delivery was 32 +/- 5 weeks, and the mean birth weight 1604 +/- 652 g. Two congenital abnormalities and one twin pregnancy were reported. 48% of deliveries were premature. Pre-eclampsia was reported in 11%, and worsening hypertension in 17%. CAPD was used in 25 and hemodialysis in 62 patients. Fetal survival was similar in both cases (72% vs 82%), although incidence of various dialysis complications differed. The conventional dialysis goals of a low target BUN level and hemoglobin for pregnant patients were not factors in predicting fetal outcome. The number of hemodialyses/week were negatively correlated (R = -0.35, P = 0.061), but the hours of dialysis positively correlated (R = 0.42, p = 0.035) to gestational age. Fetal survival was independently influenced by creatinine level [564 micromol/L when baby survived vs 788 micromol/L when baby died (p = 0.021)], BUN/creatinine ratio (50 vs 30, p = 0.053), and hours of dialysis (5.6 hrs vs 3.6 hrs, p = 0.013). There was no relation of either frequency or volume of peritoneal dialysis exchanges to gestational age or fetal survival. CONCLUSIONS: Greater attention to a high intake of protein (>1.5 g/kg) and higher dose of hemodialysis, achieved by longer, every other day dialysis, may be the optimal approach to pregnant patients on hemodialysis. Our first attempt to define the goal of hemodialysis is to keep the predialysis creatinine below 600 mmol/L and the protein intake high enough so the predialysis BUN level is >25 mmol/L. There are no clear guidelines on how to best perform CAPD.

Analysis of Variance↗
PubMed1997

Primitive reflexes and the determination of fetal presentation at birth.

Ninety term breech-presenting singletons with birth weights greater than 2500 g and no congenital anomalies were matched with similar cephalic-presenting infants on gender and mode of delivery (n = 180). Thirteen primitive reflexes were examined at birth, 6 weeks and 3 and 5 months. No significant differences in the intensity of the asymmetrical tonic neck, symmetrical tonic neck, positive support tonic labyrinthine (prone and supine), segmental rolling (head-on-body and body-on-body), Galant, Moro, upper and lower extremity grasp, lower extremity placing and stepping reflexes were observed between these two groups of infants. Infants delivered vaginally, regardless of presentation, had weaker Moro reflexes at 5 months than infants delivered by cesarean section. The popular notion that precursors to early motor behaviors, such as the placing and stepping reflexes, are determinants of fetal presentation at the end of pregnancy is not supported by these results. Instead, spontaneously generated active whole body movements may be more significant influences of fetal orientation at the time of birth.

Adult↗
PubMed1997

A randomized controlled trial of strict glycemic control and tertiary level obstetric care versus routine obstetric care in the management of gestational diabetes: a pilot study.

OBJECTIVES: The purpose of this study was to determine whether strict maternal glycemic control for the treatment of gestational diabetes lessened the risk of fetal macrosomia, birth trauma, neonatal hypoglycemia, and operative delivery. The aim of the pilot study was to prepare for a multicenter trial by assessing patient acceptance of the study, by determining realistic accrual rates, and by detecting any major adverse outcomes in the control group that received routine obstetric care. STUDY DESIGN: The study was a prospective randomized controlled trial comparing fetal-neonatal and maternal outcomes in 300 women with gestational diabetes. Women randomized to the treatment arm were managed by strict glycemic control and tertiary level obstetric care, and women in the control arm received routine obstetric care. RESULTS: Three hundred women with gestational diabetes mellitus were studied. There was no difference in maternal age, weight, or length of gestation between groups. The treatment mean birth weight was 3437 +/- 575 gm compared with 3544 +/- 601 gm in the control group, a difference of 107 gm (not significant). Macrosomia rates were similar. There was no birth trauma in either group. The frequency of neonatal hypoglycemia and other metabolic complications was the same. The mode of delivery also showed similar patterns. The treatment group had significantly lower preprandial and postprandial glucose levels by 32 weeks' gestation, which continued to term. CONCLUSION: This pilot study suggests that intensive treatment of gestational diabetes mellitus may have little effect on birth weight, birth trauma, operative delivery, or neonatal metabolic disorders. It has demonstrated the safety of proceeding to a multicenter trial of sufficient sample size to confirm these findings.

Adult↗
PubMed1997

Gestational diabetes mellitus. Unresolved issues and future research directions.

OBJECTIVE: To summarize the controversial aspects of gestational diabetes (GDM) and introduce readers to possible relevant research questions that could be examined to provide clinicians with good-quality data on which to base decisions about this relatively common pregnancy-related issue. DATA SOURCES AND STUDY SELECTION: Ongoing review of the English literature related to GDM. Sources were not restricted to prospective, controlled trials, as these are severely limited in number. SYNTHESIS: Controversial issues include the relevance of GDM to clinically meaningful outcomes in the index pregnancy, the effectiveness of current therapy in altering these outcomes, and the resultant questionable relevance of routine screening and diagnosis of an entity with as yet uncertain significance in pregnancy. CONCLUSIONS: Suggested questions to be addressed in multicentre controlled trials include randomization with respect to screening and with respect to treatment. Until such trials are completed, continuing with a standard approach to screening, diagnosis, and treatment, such as that suggested by the third international workshop on GDM, is recommended.

Cost-Benefit Analysis↗
PubMed1980

The cytoskeleton in Chediak-Higashi syndrome fibroblasts.

The Chediak-Higashi syndrome (CHS) trait is expressed in cultured human skin fibroblasts as an abnormal perinuclear concentration of moderately enlarged lysosomes. The cytoskeleton of CHS fibroblasts appears intact. Microtubules are normal in number and morphology, as assessed by colchicine binding studies, antitubulin immunofluorescence, and electron microscopy. Deformability by shear force is unaltered and microfilaments are abundant. However, CHS lysosomes appear to interact abnormally with the cytoskeleton, since the perinculear aggregation partially disperses after depolymerization of cell microtubules with colchicine. These results suggest that CHS is associated with a defect of either the lysosomal membrane itself or of lysosomal membrane-microtubule interaction.

Acridine Orange↗
PubMedDate not supplied

Relative importance of maternal constitutional factors and glucose intolerance of pregnancy in the development of newborn macrosomia.

The purpose of this case-control study was to determine the relative importance of various predictors of newborn macrosomia, with particular reference to maternal constitutional factors and glucose intolerance of pregnancy. Macrosomia was defined by both absolute birthweight > or = 4,000 g and birthweight > or = 90th centile for gestational age. One thousand mother/newborn pairs [209 macrosomic (cases) and 791 non-macrosomic newborns (controls)] were recruited. Mothers with pre-gestational diabetes mellitus were excluded. Data on pregnancy and pregnancy variables were collected by review of prenatal, labour, and delivery and newborn assessment records and interview with the mother. Predictors that entered the stepwise multiple regression model in order of significance were: previous history of macrosomia, increasing maternal weight, nonsmoking status, multiparity, male newborn gender, gestational age of 40-42 weeks, North American Aboriginal ethnicity, maternal birthweight > 4,000 g, maternal height and maternal age < 17 years. Glucose screen positive/100-g oral glucose tolerance test (GTT) negative status was a significant predictor for macrosomia as defined by birthweight greater than the 90th percentile for gestational age, but not for absolute birthweight over 4,000 g. It was the least significant of all the factors examined. Treated gestational diabetes was not a significant predictor. By multivariate analysis, maternal constitutional factors are more powerful predictors of newborn macrosomia than maternal mild glucose intolerance. Treatment of mothers with GDM may be masking the effect of more pronounced carbohydrate intolerance.

Adolescent↗