Biomedical subjects

D Chitayat

Publications and source records attributed to D Chitayat.

At least 91 records · Page 5Linked to original sources

PubMed1996

Nicotine and cotinine in maternal and neonatal hair as markers of gestational smoking.

OBJECTIVE: To determine the extent of fetal exposure to cigarette smoke, which cannot be clearly extrapolated from maternal reports, the authors measured concentrations of nicotine and cotinine in maternal and neonatal hair and corroborated these measures with maternal history and measures of pregnancy outcome. DESIGN: Prospective study of 94 mother-infant pairs. SETTING: Newborn nurseries of two hospitals in Toronto. PARTICIPANTS: 93 mothers, including active smokers, passive smokers and nonsmokers, and their newborns (including one set of twins). INTERVENTIONS: Hair collected from mothers and neonates shortly after birth was analysed by radio-immunoassay. MAIN OUTCOME MEASURES: Maternal data on demographic variables, obstetric history, diseases, drugs taken and smoking; infant data on demographic variables and birth indicators (gestational age, method of delivery, weight, head circumference, length, presence of meconium, need for resuscitation, need for special care and congenital malformations); hair concentrations of nicotine and cotinine. RESULTS: Neonates of active smokers had more adverse outcomes than other infants, including lower birth weight, smaller head circumference, shorter length and more perinatal complications. The difference was statistically significant. Amounts of cotinine extracted from mothers' and infants' hair showed significant differences among active smokers, passive smokers and non-smokers. When other people in the household and the mother smoked, neonatal hair concentrations of nicotine and cotinine in the infants were threefold higher than those in the infants of mothers who were the only smokers in their households. CONCLUSIONS: Hair concentrations of nicotine and cotinine are a powerful biological marker of the extent of intrauterine exposure to tobacco smoke.

Adolescent↗

PubMed1995

Prenatal diagnosis of retinal nonattachment in the Walker-Warburg syndrome.

We report on the prenatal ultrasonographic diagnosis of Walker-Warburg syndrome based on cerebral and ocular findings. The ultrasound study done at 37 weeks gestation documented hydrocephalus and retinal nonattachment consistent with this syndrome. The ability to detect retinal nonattachment prenatally may have implications for the prenatal diagnosis of other conditions which have early retinal nonattachment as one of their findings. However, it is uncertain how early in pregnancy this defect can be detected.

Abnormalities, Multiple↗

PubMed1995

Prenatal diagnosis and fetopathological findings in five fetuses with trisomy 9.

Five male fetuses with trisomy 9 are discussed. Three were detected prenatally and terminated, 1 aborted spontaneously, and the fifth delivered prematurely and died soon after. Multiple congenital abnormalities characteristic of trisomy 9 were detected in all 5 cases and are compared to those of previous reports.

Abnormalities, Multiple↗

PubMed1995

Syndrome of proximal interstitial deletion 4p15: report of three cases and review of the literature.

We report on two boys and a girl with interstitial deletion in the short arm of chromosome 4 including the segment p15.2p15.33. All had normal growth with psychomotor retardation, multiple minor congenital anomalies, and a characteristic face distinct from that of the Wolf-Hirschhorn syndrome. One of the patients had congenitally enlarged penis. These patients resemble some of the previously reported patients with similar cytogenetic abnormalities and suggests the recognition of a specific clinical chromosome deletion syndrome.

Abnormalities, Multiple↗

PubMed1995

The prognostic factors in the prenatal diagnosis of the echogenic fetal lung.

The prenatal diagnosis of an echogenic fetal lung (EFL) is now often made in the early second trimester using high-resolution ultrasound. This ultrasound appearance is usually caused by a congenital cystic adenomatoid lung malformation (CCAM), an intrapulmonary lung sequestration or obstruction of a major airway. In order to provide prognostic guidelines to parents who may be considering termination of a fetus with these findings, we have analysed a series of 11 cases diagnosed in our centre over the past 2 years in conjunction with 60 cases from major published series. The data suggest that in the absence of non-immune hydrops fetalis (NIHF) or other anomalies, the outcome for the fetuses is excellent, with over 90 per cent survival. Neither early diagnosis (24 weeks) nor the presence of mediastinal shift is a poor prognostic indicator. In addition, it appears that if NIHF is absent at diagnosis, the chance that it will develop as the pregnancy continues is small (6 per cent). Furthermore, there is a significant (up to 30 per cent) chance that this ultrasound finding will resolve in utero. The development of in utero fetal surgical techniques may be the only hope for those hydropic fetuses who appear to have a dismal prognosis.

Bronchopulmonary Sequestration↗

PubMed1995

Genetic homogeneity of cartilage-hair hypoplasia.

Cartilage-hair hypoplasia (CHH) is an autosomal recessive metaphyseal chondrodysplasia characterized by short stature and hypoplasia of the hair. Associated pleiotropic features include deficient erythrogenesis, impaired T-cell mediated immunity, Hirschsprung's disease, and an increased risk of malignancies. CHH is most prevalent among the Old Order Amish in the United States and among the Finns, but sporadic families have been described among many other populations. We have previously mapped the gene for CHH to the short arm of chromosome 9 in Finnish and Amish families. The CHH locus resides close to D9S163 within an interval of 1.5 cM flanked by D9S165 and D9S50. In order to investigate the genetic homogeneity of CHH in various populations, we studied nine families with no genealogical connections to either Amish or Finns. No recombinants were detected between the CHH gene and any of the three closest marker loci studied, suggesting that CHH in these families results from mutation(s) at the same locus as in the Amish and Finnish families.

Canada↗

PubMed1995

Spectrophotometry of amniotic fluid: a simple and rapid method for distinguishing between gestational sacs in second-trimester amniocentesis of twin pregnancies.

OBJECTIVE: To evaluate the use of an alternative and simple spectrophotometric method that could replace the intraamniotic injection of dye in the second-trimester amniocentesis of twins. METHODS: Optical densities (OD) of amniotic fluid (AF) obtained at second-trimester genetic amniocentesis were measured at 360 nm. Comparison was made between 36 twin pregnancies and 60 singleton controls. RESULTS: The mean difference in OD between two samples taken from the same sac of singleton pregnancies was very small (mean 0.004, standard deviation [SD] 0.003). However, samples drawn from each of the twin pairs' amniotic sacs varied widely (raw mean 0.176, SD 0.223; median 0.096, range 0.011-0.943). The difference between the groups was highly significant statistically (P < .001). CONCLUSION: Our preliminary experience with spectrophotometry of AF in twin amniocentesis suggests that this simple test may be useful in ascertaining that the AF samples were obtained from each of the two gestational sacs.

Amniocentesis↗

PubMed1995

The 13q- syndrome: the molecular definition of a critical deletion region in band 13q32.

Patients with interstitial deletions of the long arm of chromosome 13 may have widely varying phenotypes. From cytogenetic analysis, we have postulated that there is a discrete region in 13q32 where deletion leads to a syndrome of severe malformations, including digital and brain anomalies. To test this hypothesis at the molecular level, we have studied the deletions in 17 patients; 5 had severe malformations, while the remaining 12 had only minor malformations. Our results indicate that the deletions in the severely affected patients all involve an overlapping region in q32, while the deletions in the mildly affected patients include some, but not all, of this overlapping region. Our findings are consistent with the hypothesis that the severely malformed 13q- phenotype results from the deletion of a critical region in 13q32. This region is presently defined as lying between D13S136 and D13S147 and is on the order of 1 Mb in size.

Abnormalities, Multiple↗

PubMed1994

Familial Dandy-Walker malformation associated with macrocephaly, facial anomalies, developmental delay, and brain stem dysgenesis: prenatal diagnosis and postnatal outcome in brothers. A new syndrome?

Brothers are reported with an apparently new constellation of manifestations including Dandy-Walker complex (DWC), migrational brain disorder, macrocephaly, and facial anomalies. The first brother presented at birth, the second was detected prenatally with DWC and the pregnancy terminated. Fetal brain histopathology showed DWC associated with brainstem dysgenesis. Inheritance is likely autosomal or X-linked recessive. An extensive review of the differential diagnosis of DWC is provided.

Adult↗

PubMed1994

Hair concentrations of nicotine and cotinine in women and their newborn infants.

BACKGROUND: To date, no biological markers have been identified that can predict the extent of fetal exposure to the toxic constituents of cigarette smoke. A variety of xenobiotic agents have been shown to accumulate in growing hair. PATIENTS AND METHODS: We measured maternal and neonatal hair concentrations of nicotine and cotinine in 94 mother-infant pairs. Mothers who were active smokers, nonsmokers, and passive smokers and their infants were included. RESULTS: Mothers who were active smokers (n = 36) had mean (SEM) hair concentrations of 19.2 (4.9) ng/mg for nicotine and 6.3 (4.0) ng/mg for cotinine, significantly higher than concentrations in nonsmokers (n = 35) (1.2 [0.4] ng/mg for nicotine and 0.3 [0.06] ng/mg for cotinine, P < .0001). Infants of smokers had mean hair concentrations of 2.4 (0.9) ng/mg for nicotine (range, 0 to 27.3 ng/mg) and 2.8 (0.8) ng/mg for cotinine (range, 0 to 12.2 ng/mg), significantly higher than concentrations in infants of nonsmokers (0.4 [0.09] ng/mg for nicotine and 0.26 [0.04] ng/mg for cotinine, P < .01). Mothers with passive smoke exposure and their infants (n = 23) had significantly higher hair concentrations of nicotine (3.2 [0.8] ng/mg for mothers and 0.28 [0.05] ng/mg for infants) and cotinine (0.9 [0.3] ng/mg for mothers and 0.6 [0.15] ng/mg for infants) than nonsmoking mothers and their infants (P < .01). There was a significant correlation between maternal and neonatal hair concentrations of nicotine (r = .49, P < .001) or cotinine (r = .85, P = .0001). CONCLUSIONS: This is the first biochemical evidence that infants of passive smokers are at risk of measurable exposure to cigarette smoke. Hair accumulation of cigarette smoke constituents reflects long-term systemic exposure to these toxins and therefore may be well correlated with perinatal risks.

Adult↗

PubMed1994

Penoscrotal transposition: a case report and review.

We report on a boy born with complete penoscrotal transposition, normal scrotum, twisted penile shaft with hypoplastic penile urethra, meatal stenosis, normal bladder, and bilateral cystic dysplastic kidneys. The patient died of renal failure at 2.5 months. This is the 13th reported case of complete penoscrotal transposition with normal scrotum. The possible pathogenesis is discussed and the literature is reviewed.

Abnormalities, Multiple↗

PubMed1994

Recurrent missense mutations at the first and second base of codon Arg243 in human lipoprotein lipase in patients of different ancestries.

Mutations in the lipoprotein lipase (LPL) gene are the most common cause of familial chylomicronemia. Here we define the molecular basis of LPL deficiency in four patients of German, French, Dutch, and Chinese descent. We show that two of the probands of Dutch and Chinese origin have a previously described Arg243His mutation while the patients of German and French descent have a novel Arg243Cys substitution in their LPL gene. Haplotype analysis is in favour of two separate origins for the Arg243Cys substitution which together with the Arg243His mutation would implicate three recurrent mutations involving the first and second nucleotides of the codon encoding Arg243 of the LPL gene. The recurrent mutations affecting the first and second nucleotide of CGC coding for the normal Arg residue are support for the high mutability of CpG dinucleotides within the LPL gene.

Adult↗

PubMed1994

Hb FM-Fort Ripley: confirmation of autosomal dominant inheritance and diagnosis by PCR and direct nucleotide sequencing.

We describe a normal neonate who presented at four days of age with asymptomatic cyanosis. There was no evidence of cardiac or pulmonary abnormality and an extended family history included 13 other affected family members with asymptomatic cyanosis lasting one to three months. Polymerase chain reaction (PCR) amplification and direct nucleotide sequencing of the proband's G gamma chain gene revealed the mutation at codon 92 (CAC-->TAC) previously shown in haemoglobin FM-Fort Ripley (alpha 2 gamma G gamma 92 (F8) His-->Tyr). This is the first family with Hb FM-Fort Ripley reported so far. It demonstrates autosomal dominant inheritance of this condition and incomplete penetrance.

Amino Acid Sequence↗

PubMed1994

Regional expression of CFTR in developing human respiratory tissues.

Morbidity and mortality in cystic fibrosis (CF) patients is strongly related to their respiratory disease. We have analyzed, by means of in situ hybridization, the localization and levels of CFTR mRNA in fetal, newborn, and infant respiratory tissues. Measurable levels of CFTR transcript are present in the fetal primordial epithelium of the pseudoglandular stage lung. During the following stages of lung development, CFTR expression decreases in cells of the future alveolar spaces and is gradually limited to the epithelium of the small airways. After birth, expression decreases in the small airways and is not detected in alveolar epithelia. In trachea and large bronchi, a differential pattern of expression is also observed. No CFTR expression is found in fetal submucosal glands during fetal development, but appears gradually in the newborn period. Since CFTR codes for a secretory Cl- channel, these data probably reflect the changes that occur in the lung transition from a fluid-secreting to an absorbing organ. The pattern of expression seems paradoxical in view of the clinical-pathological manifestations of CF. Although CFTR is expressed in the normal fetus and lung development is influenced by the amount of fetal lung liquid, newborns affected with CF have normal lungs. In addition, the earliest pathologic change described in CF lungs in hyperplasia of the submucosal glands, yet expression in these structures is seen only after birth. An improved understanding of the factors that alter the expected relationship between CFTR expression and pathologic lesions in the fetal lung may provide important insights into the pathogenesis and potential treatment of lung disease in CF patients.

Child, Preschool↗

PubMed1994

Differential cellular expression of cystic fibrosis transmembrane regulator in human reproductive tissues. Clues for the infertility in patients with cystic fibrosis.

Cystic fibrosis (CF) is characterized by a wide spectrum of clinical manifestations, including reproductive problems. Practically all males affected by the disease are infertile due to azoospermia associated with pathology of the male ducts, whereas females with CF have reduced fertility. To study the mechanism of reproductive pathology in CF patients, we analyzed the levels and localization of expression of the cystic fibrosis transmembrane regulator (CFTR) gene in relevant postnatal tissues. Significant expression was detected in the epithelium of the epididymis and vas deferens. Minimal expression, not associated with specific cell types, was seen in the mature testis. In female genitalia, variable levels of expression were seen in the cervical epithelium and fallopian tube. The endometrial epithelium and glands expressed CFTR at high levels only after puberty. No expression was seen in ovaries. Deficient secretory function of CFTR in males but not in females may lead to organ damage probably as a consequence of excessive concentration of viscid luminal contents.

Adult↗

PubMed1993

Evidence for multi-site closure of the neural tube in humans.

Four separate initiation sites for neural tube (NT) fusion have been demonstrated recently in mice and other experimental animals. We evaluated the question of whether the multisite model vs. the traditional single-site model of NT closure provided the best explanation for neural tube defects (NTDs) in humans. Evidence for segmental vs. continuous NT closure was obtained by review of our recent clinical cases of NTDs and previous medical literature. With the multi-site NT closure model, we find that the majority of NTDs can be explained by failure of fusion of one of the closures or their contiguous neuropores. We hypothesize that: Anencephaly results from failure of closure 2 for meroacranium and closures 2 and 4 for holoacranium. Spina-bifida cystica results from failure of rostral and/or caudal closure 1 fusion. Craniorachischisis results from failure of closures 2, 4, and 1. Closure 3 non-fusion is rare, presenting as a midfacial cleft extending from the upper lip through the frontal area ("facioschisis"). Frontal and parietal cephaloceles occur at the sites of the junctions of the cranial closures 3-2 and 2-4 (the prosencephalic and mesencephalic neuropores). Occipital cephaloceles result from incomplete membrane fusion of closure 4. In humans, the most caudal NT may have a 5th closure site involving L2 to S2. Closure below S2 is by secondary neurulation. Evidence for multi-site NT closure is apparent in clinical cases of NTDs, as well as in previous epidemiological studies, empiric recurrence risk studies, and pathological studies. Genetic variations of NT closures sites occur in mice and are evident in humans, e.g., familial NTDs with Sikh heritage (closure 4 and rostral 1), Meckel-Gruber syndrome (closure 4), and Walker-Warburg syndrome (2-4 neuropore, closure 4). Environmental and teratogenic exposures frequently affect specific closure sites, e.g., folate deficiency (closures 2, 4, and caudal 1) and valproic acid (closure 5 and canalization). Classification of NTDs by closure site is recommended for all studies of NTDs in humans.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1993

Hydrops-ectopic calcification-moth-eaten skeletal dysplasia (Greenberg dysplasia): prenatal diagnosis and further delineation of a rare genetic disorder.

An offspring of consanguineous parents of East-Indian origin was found prenatally to have hydrops fetalis, short limb dwarfism, polydactyly and chondro-osseous changes consistent with Greenberg hydrops-ectopic calcification-moth-eaten skeletal dysplasia (HEM) dysplasia. The radiological changes include platyspondyly with multiple extra ossification centers, extraneous calcification in the ribs, sternum, pelvis, and epiphysis, and moth-eaten long bones. The histopathological changes included chondrocytes with dilated rough endoplasmic reticulum and inclusion bodies with homogeneous material of intermediate electron density. These findings further delineate the spectrum of this rare autosomal recessive skeletal dysplasia.

Abnormalities, Multiple↗

PubMed1993

Trisomy 22 and facioauriculovertebral (Goldenhar) sequence.

We report on an infant girl born with complete trisomy 22 and left hemifacial microsomia, ear anomaly, and limbal and epibulbar complex choristoma. Trisomy 22 was confirmed by prometaphase chromosome analysis and in situ hybridization. This patient extends the list of chromosome abnormalities associated with apparent Golenhar sequence and emphasizes the importance of chromosome analysis in the investigation of patients with this condition. A detailed ophthalmopathological investigation is reported.

Abnormalities, Multiple↗