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Biomedical subjects

K M Lewis

Publications and source records attributed to K M Lewis.

At least 19 recordsLinked to original sources
PubMed2001

Method for determination of pentobarbital in dry dog food by gas chromatography/mass spectrometry.

A procedure has been developed and validated for measuring the concentration of pentobarbital residues in dry, extruded animal feed in the range of 3-200 ng/g (ppb) with an estimated limit of quantitation of 2 ppb. The method was developed for surveillance purposes: to measure the concentration of euthanizing agent which might be present in feeds incorporating rendered products which themselves might include some fraction of euthanized animals. A previously published qualitative procedure was modified by adding isotopically labelled pentobarbital as an internal standard. Dry feed was ground and extracted with methanol. The extract was loaded on a mixed-mode (C-18, anion exchange) solid-phase extraction cartridge designed for barbiturate residues. Pentobarbital was eluted and derivatized for gas chromatography/mass spectrometry in positive ion chemical ionization mode. Quantitation was based on the ratio of dimethyl-pentobarbital MH+ (m/z 255) vs dimethyl-pentobarbital-d(5) (m/z 260) in standards and extracts. Accuracy ranged from 112% at 3 ppb to 96% at 200 ppb, with relative standard deviations ranging from 4% at 3 ppb to 2% at 200 ppb.

Animal Feed↗
PubMed1999

Glycosylated hemoglobin as a predictor of fetal pulmonic maturity in insulin-dependent diabetes at term.

In insulin dependent diabetic (IDDM) gestations, fetal pulmonary maturity is delayed in the presence of suboptimal glycemic control. Serum glycosylated hemoglobin (HbA1c) provides a means of assessing glycemic control. We evaluated maternal HbA1c in IDDM pregnancies at term undergoing amniocentesis for lung maturity to establish if euglycemia is associated with improved fetal lung maturity. Between July 1995 and June 1996, IDDM patients undergoing amniocentesis at term for lung maturity studies had a maternal serum sample analyzed for HbA1c. Fetal lung maturity was established by the presence of phosphatidylglycerol (PG) in amniotic fluid. HbA1c was considered elevated if >6.2%. Mean HbA1c level was 6.8% (range 4.4 to 9.9%). PG was present in 54% of patients with elevated HbA1c (7/13) versus 80% of those with normal HbA1c (8/10) (p = 0.4). Although birth weight was higher in the elevated than in the normal HbA1c group (3770 +/- 514 vs. 3215 +/- 610 g), no association was present between birth weight and HbA1c level (r = 0.22, p = 0.4). The rate of a mature pulmonic profile at term is not significantly different between IDDM women with good or poor glycemic control. HbA1c values should not be used to predict the presence or absence of amniotic fluid PG.

Adult↗
PubMed1999

Association of sex of the fetus in isolated fetal choroid plexus cysts.

We sought to determine if an association exists between sex of the fetus and the finding of isolated fetal choroid plexus cysts. Of 131 fetuses, 62 were male (47.3%) and 69 were female (52.7%). No statistically significant differences were found in the maternal demographic parameters studied (age, race, gravidity, parity, sonogram timing) or descriptive cyst information obtained (location, number, dimensions, resolution), although bilaterality was more common in male fetuses. The determination that isolated choroid plexus cysts are seen equally frequently in male and female fetuses adds to basic information about such a common sonographic finding.

Brain Diseases↗
PubMed1998

Complications of intrauterine placement of a vesicoamniotic shunt.

BACKGROUND: Fetal obstructive uropathies complicated by severe oligohydramnios can cause neonatal death due to renal dysplasia and pulmonary hypoplasia. CASE: A 31-year-old multigravida was referred at 19.6 weeks with sonographic evidence of fetal megacystis and bilateral hydroureteronephrosis, and severe oligohydramnios. A vesicoamniotic shunt was placed for urinary diversion. Complications included shunt migration, intestinal evisceration, amniorrhexis, preterm labor, and preterm delivery. Bowel characteristics were assessed by measuring the intestinal lumen diameter for evidence of obstruction. The lumen diameter remained stable at 3-5 mm, and the luminal wall remained stable at 2.5 mm. After birth at 31 weeks, the infant underwent exploratory laparotomy and extraction of malpositioned shunts, vesicostomy, and closure of abdominal wall defect. He was discharged at 61 days of life after resolution of neonatal pulmonary and infectious complications. CONCLUSION: Operative management of complete fetal obstructive uropathy is beneficial despite potential complications.

Adult↗
PubMed1998

The risk of infection with HIV and hepatitis B in individuals who inject steroids in England and Wales.

Data on injecting anabolic steroid users, within the national Unlinked Anonymous HIV Prevalence Monitoring Survey of injecting drug users (IDUs) were analysed to determine their risk of acquiring blood borne viruses. One hundred and forty-nine participants who had injected anabolic steroids in the previous month were identified from 1991-6, contributing 1.4% of all participation episodes in the survey. Rates of needle and syringe sharing by steroid users were low. Three of the 149 (2.0%) had anti-HBc and none had anti-HIV in their salivary specimens. The prevalence of anti-HBc in steroid injectors was significantly lower than in heroin injectors, 275/1509 (18%) (P < 0.001), or in amphetamine injectors, 28/239 (12%) (P < 0.001). The risk of blood borne virus transmission amongst these steroid injectors is low, probably due to hygienic use of injecting equipment and low levels of sharing. It is important to distinguish steroid injectors from other IDUs because they are a distinct group in terms of lifestyle and injecting practice.

Adolescent↗
PubMed1996

Mid-trimester prenatal sonographic diagnosis of a pericardial cyst.

Prenatal diagnosis of pericardial masses are infrequent and usually consist of intrapericardial teratomas or haemangiomas. We present the first report of prenatal diagnosis of a suspected pericardial cyst at 14 weeks' gestation which was subsequently confirmed by neonatal computed tomography.

Adult↗
PubMed1996

Prenatal diagnosis of an infant with mosaic trisomy 16 of paternal origin.

We present the first case of an infant with paternally-derived mosaic trisomy 16. Amniocentesis following an elevated maternal serum alpha-fetoprotein level and early fetal growth restriction at 19 weeks detected a high level of mosaicism with 25/33 colonies demonstrating trisomy 16 and 8/33 colonies with a normal 46,XX karyotype. Molecular studies revealed a paternal origin of the trisomy which was present in amniotic fluid cells, representing either a post-zygotic error or a meiosis II non-disjunction without crossing-over. In addition, there was normal biparental inheritance in the normal cell line. The symmetrically growth-restricted fetus was closely monitored for the remainder of the gestation. Decreased fetal movements at 36 weeks in conjunction with electronic fetal monitoring showing evidence of fetal distress necessitated abdominal delivery. Severe growth restriction, mild facial dysmorphism, and cardiac anomalies were identified. Microsatellite analysis demonstrated biparental inheritance in skin fibroblasts with a paternal origin for the trisomy in the placenta. Follow-up cytogenetic studies of additional tissues revealed 85 per cent trisomy 16 mosaicism in the placenta, yet only cytogenetically normal cells in lymphocytes and fibroblasts.

Amniocentesis↗
PubMed1996

Prenatal color and pulsed Doppler sonographic documentation of intrathoracic umbilical vein and ductus venosus, confirming extensive hepatic herniation in left congenital diaphragmatic hernia.

Prenatal sonographic diagnosis of an unusual case of a large left congenital diaphragmatic hernia is presented. The fetal stomach was located within the right thorax, posterior to the dextropositioned heart. Color and pulsed Doppler ultrasonography documented intrathoracic umbilical vein and ductus venosus vessels and respective waveforms, confirming extensive herniation of the left hepatic lobe.

Adult↗
PubMed1985

Monoclonal antibodies against a component related to soluble estrogen receptor.

Mice were immunized with 1 to 3 micrograms of cytoplasmic estrogen receptor fragment purified from human myometrium by affinity chromatography. Two RE-antibody-secreting clones were detected from one fusion that were capable of precipitating cytosol RE. Monoclonal antibody D5 (subclass IgG1) reacts with an antigen that is related to RE from immunoprecipitation studies but which can be separated from the hormone binding unit. In the presence of anti-mouse serum, D5 precipitates labeled human cytoplasmic RE complexes from breast tumor, fibroid, myometrial, and endometrial preparations but does not react with nuclear RE from human endometrium or cytoplasmic RE from other species tested. Conversely, antibody C3 (Class IgM) precipitates human cytoplasmic RE and nuclear RE complexes as well as labeled cytoplasmic RE from rat and calf uterus and chick oviduct. Neither antibody reacts with progesterone receptor or androgen receptor from human breast tumor, SHBG from human plasma, or rat alpha-fetoprotein. With D5, steroid labeling of cytoplasmic RE at 25 degrees increased the RE immune complex precipitated. D5 precipitates molybdate-stabilized RE from myometrial cytosol when labeled at 25 degrees but not at 4 degrees. C5 precipitates molybdate-stabilized RE whether cytosol was steroid-labeled at 4 degrees or 25 degrees. For D5, optimal precipitation of RE from human breast tumor was observed when cytosol was steroid-labeled at 25 degrees in buffers of pH range 5 to 6. Immunochemical studies indicate that D5 is associated with a Mr 29,000 component in RE-positive cytosols. Electrofocusing and sucrose density gradient analysis confirmed that D5 antigen is a non-hormone-binding component related to cytosolic RE from breast tumor and myometrium.

Animals↗
PubMed1985

Immunoradiometric studies with monoclonal antibody against a component related to human estrogen receptor.

A human specific monoclonal antibody (D5) raised against a Mr 36,000 cytosolic estrogen receptor component (RE) partially purified from human myometrium was used to develop a simple, rapid, and sensitive solid-phase immunoradiometric assay (IRMA) for the reactive antigen in tissue cytosols from breast tumors, myometrium, endometrium, and endometrial carcinomas. The IRMA did not detect antigen in RE-negative cytosols from human breast tumors and endometrial carcinomas. RE-positive cytosols from chick oviduct and calf and rat uteri failed to produce an IRMA response. A pilot study indicated a significant correlation (P less than 0.001) between D5 IRMA value and RE sites in breast tumors assayed by [3H]estradiol binding sites. The presence of D5 antigen was dependent on the presence of cytosolic RE but not progesterone receptor. RE-positive patients age 50 years and over demonstrated significantly higher D5 assay values than did patients under 50 years. The data suggest that the D5 antigen is a component of the estrogen receptor or coordinately regulated with the receptor in human cells and that the assay method may have clinical use.

Adult↗
PubMed1979

pKa values of estrone, 17 beta-estradiol and 2-methoxyestrone.

The acid ionization constants of estrone (10.77), 17 beta-estradiol (10.71) and 2-methoxyestrone (10.81) have been determined spectrophotometrically and shown to be consistent with the additivity of substituent effects of the phenol ring. Previously published values for estrone (10.914) and 17 beta-estradiol (10.078) are shown to be incorrect, at variance with the established trend for phenols, and inconcsistent with the similarity of the compounds.

Estradiol↗