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Biomedical subjects

C Bailey

Publications and source records attributed to C Bailey.

At least 73 records · Page 4Linked to original sources
PubMed1994

Phenotypic variability in X-linked ocular albinism: relationship to linkage genotypes.

One hundred nineteen individuals from 11 families with X-linked ocular albinism (OA1) were studied with respect to both their clinical phenotypes and their linkage genotypes. In a four-generation Australian family, two affected males and an obligatory carrier lacked cutaneous melanin macroglobules (MMGs); ocular features were identical to those of Nettleship-Falls OA1. Four other families had more unusual phenotypic features in addition to OA1. All OA1 families were genotyped at DXS16, DXS85, DXS143, STS, and DXS452 and for a CA-repeat polymorphism at the Kallmann syndrome locus (KAL). Separate two-point linkage analyses were performed for the following: group A, six families with biopsy-proved MMGs in at least one affected male; group B, four families whose biopsy status was not known; and group C, OA-9 only (16 samples), the family without MMGs. At the set of loci closest to OA1, there is no clear evidence in our data set for locus heterogeneity between groups A and C or among the four other families with complex phenotypes. Combined multipoint analysis (LINKMAP) in the 11 families and analysis of individual recombination events confirms that the major locus for OA1 resides within the DXS85-DXS143 interval. We suggest that more detailed clinical evaluations of OA1 individuals and families should be performed for future correlation with specific mutations in candidate OA1 genes.

Albinism, Ocular↗
PubMed1993

Bone lead content assessed by L-line x-ray fluorescence in lead-exposed and non-lead-exposed suburban populations in the United States.

Measurements of lead (Pb) in bone reflect cumulative Pb exposure, whereas blood Pb levels are indices of absorption during the previous 21-30 days. This study was undertaken to estimate bone Pb concentrations by L-line x-ray fluorescence (LXRF) in a United States suburban population which was exposed to unusually high levels of Pb in emissions from an adjacent factory during 1963-1981, compared with concentrations similarly estimated in a matched suburban community without unusual Pb exposure. The mean bone Pb value in 269 residents of the highly exposed suburb (15 ppm) was 3-fold greater than that of the reference suburb (5 ppm). LXRF estimates of bone Pb identified those individuals at risk for adverse effects of Pb, whereas blood Pb levels were uninformative. Average LXRF-estimated bone Pb concentrations in residents of the unusually exposed suburb approximated estimated values in workers at Pb-processing factories.

Adolescent↗
PubMed1993

Biotin uptake and transport across bovine brain microvessel endothelial cell monolayers.

Primary cultures of bovine brain microvessel endothelial cells (BMECs) were used to characterize blood-brain barrier (BBB) uptake and transport of biotin. Both the uptake and the transcellular transport of either radiolabeled or fluorescein-conjugated biotin by confluent monolayers of BMECs were measured. Biotin uptake (Km = 123 microM) and bidirectional transport across BMEC monolayers was a saturable process and could be competed for by unlabeled biotin, biocytin, and biotinmethyl ester. Pantothenic and nonanoic acid were found not to be effective competitors for either biotin uptake or transport. The metabolic inhibitor, 2-deoxyglucose, had only small effects on the saturable apical-to-basolateral transport and apical uptake of biotin by BMECs. In contrast, basolateral-to-apical transport of biotin was substantially attenuated by 2-deoxyglucose pretreatment. Results supported the existence of specific and saturable uptake and efflux carrier systems for biotin in BMEC monolayers. The function of these systems was dependent to some degree on the metabolic status of the BMECs. Our findings confirm the existence of a biotin uptake system at the BBB in vivo and provide the first indication of an efflux system for biotin in BMECs.

Animals↗
PubMed1992

Bone marrow transplantation for high-risk childhood lymphoblastic leukaemia in first remission: experience in MRC UKALL X.

Bone marrow transplantation (BMT) has been recommended for children with high-risk acute lymphoblastic leukaemia (ALL) in first remission. The recent MRC UKALL X trial was designed to facilitate a non-randomised comparison between BMT and chemotherapy in children deemed to be at high risk of treatment failure. 198 children aged 1-15 had a presenting leucocyte count of more than 100 x 10(9)/l. All received induction and early intensification therapy. Children with an HLA-compatible sibling donor were eligible for BMT in first remission. All other children received cranial irradiation at 24Gy, late intensification, and two years of continuous treatment. 183 children achieved a stable remission of whom 111 were HLA typed; these tended to be older and to have T-cell ALL. A donor was identified in 41 cases, of whom 34 proceeded to BMT at a median time of 17 weeks; there was no difference in distribution of age, sex, or leucocyte count between the groups receiving BMT and chemotherapy. Comparison of the 144 children who were in remission at 17 weeks and received chemotherapy with the 34 proceeding to BMT showed no significant difference in event-free survival at five years (69% for BMT and 52% for chemotherapy). There were significantly more treatment-related deaths in the marrow transplant group (6 vs 4) and more relapses in the chemotherapy group (59 vs 4). There was no significant difference in event-free survival between children who were HLA typed and had a donor and those without a donor, although there were fewer relapses among the former. BMT can be evaluated in the context of a multicentre trial for paediatric ALL but the number of children with donors is too small to make a significant impact on overall survival. However, marrow transplantation was associated with a much lower relapse rate than that with the UK ALL protocol, and with better definition of higher risk patients BMT may be of benefit in some children with high-risk ALL in first remission.

Adolescent↗
PubMed1992

Purification and identification of bovine liver gamma-carboxylase.

The microsomal gamma-carboxylase catalyzes modification of a limited set of glutamyl residues to gamma-carboxyglutamyl residues in a vitamin K-dependent reaction that also utilizes O2 and CO2. We report the purification to apparent homogeneity of the bovine liver microsomal carboxylase. Affinity chromatography exploiting the association of the carboxylase with prothrombin precursor and carboxylase binding to the propeptide sequence were combined with ion-exchange chromatography and fractionation using immobilized lectins. A 3.5 x 10(5)-fold purification was obtained, which is the highest purification, by a factor of 35, yet reported for this enzyme. A single 98-kDa protein is obtained from this isolation. Carboxylase activity is associated with this protein by two different criteria. Antibodies prepared against the carboxylase detected the 98-kDa protein when used in Western analysis. In addition, the single 98-kDa protein was shown to comigrate with activity when electrophoresed in a nondenaturing gel system. The availability of purified preparations of carboxylase will facilitate an increased understanding of the complex biochemical reaction carried out by this protein.

Animals↗
PubMed1992

Cation-dependent transition between the quadruplex and Watson-Crick hairpin forms of d(CGCG3GCG).

The DNA oligonucleotide d(CGCG3GCG) can form either a Watson-Crick (WC) hairpin or a parallel-stranded quadruplex structure containing six G-quartet base pair assemblies. The exchange between these forms and single strands can be monitored using circular dichroism (CD). NMR results verified the assignment of specific CD bands to quadruplex and hairpin species, respectively. Cations stabilize the quadruplex in the order K+ greater than Ca2+ greater than Na+ greater than Mg2+ greater than Li+ and K+ greater than Rb+ greater than Cs+, indicating that K+ has an optimum ionic radius for complex formation and that ionic charge affects the extent of ion-induced stabilization. The quadruplex is stable in the presence of 40 mM K+ at micromolar DNA concentration and can be kinetically trapped as a metastable form when prepared at millimolar DNA concentration and then diluted into buffer containing 40 mM Na+. The concentration of K+ required to reverse the equilibrium from the hairpin to the quadruplex decreases sharply with increased DNA concentration. The quadruplex has an unusual pKa of ca. 6.8, indicating that C.C+ base pairs are probably forming. This system provides insights into some of the detailed structural characteristics of a ["G4-DNA".ion] complex and an experimental model for the recently proposed "sodium-potassium conformational switch" [Sen, D., & Gilbert, W. (1988) Nature 334, 364-366; Sen, D., & Gilbert, W. (1990) Nature 344, 410-414]. These results may help to explain the lack of cytidine residues in G-rich telomeric DNAs and suggest that methylation of GC-rich duplex DNAs in "GpC islands" may induce quadruplex formation within heterochromatin domains, resulting in reversible chromosomal condensation.

Base Sequence↗
PubMed1992

Intrapartum fetal stimulation testing.

Intrapartum vibroacoustic stimulation testing (VAST) had a sensitivity of 100%, a specificity of 59.6% and a positive predictive value of 27.6% for the detection of fetal acidosis in this study of 60 cases. The use of VAST could significantly reduce the requirement for fetal capillary blood sampling. However, fetal scalp stimulation (FSS) was found to be an unreliable test to exclude fetal acidosis.

Acidosis↗
PubMed1992

Measurement of dopamine, HVA and HMMA in untimed urine samples: establishment of age-related reference data in children.

We describe assays for homovanillic acid, hydroxymethylmandelic acid and dopamine that have proven practical and reliable during 3 years of routine use. Homovanillic and hydroxymethylmandelic acids were measured as trimethyl silyl derivatives by capillary gas chromatography. Dilution of samples prior to extraction was found to be necessary to achieve consistent recoveries of these acidic metabolites. Dopamine was assayed by high pressure liquid chromatography with electrochemical detection using an optimized method of catecholamine isolation that involved both ion exchange and alumina extraction. Untimed urine samples were collected from 140 hospitalized children. Age related reference data for the excretion of all three metabolites are reported. We suggest certain precautions that should be observed when using untimed samples and relating the results to creatinine excretion.

Adolescent↗
PubMed1991

Comparison of the structure of the genes for outer membrane proteins P1 and P2 of Haemophilus influenzae type b.

Size and antigenic heterogeneity have been recognized in both outer membrane protein P1 and outer membrane protein P2 of Haemophilus influenzae type b. To determine the molecular basis for these differences, we have cloned and sequenced the structural genes for OMPs P1 and P2 from prototype isolates with the OMP subtypes 1H, 3L and 6U. The nucleotide and derived amino acid sequences of the P1 genes are characterized by three variable regions dispersed between highly conserved regions. The nucleic acid and derived amino acid sequences of the P2 genes are also highly conserved. The P2 genes from OMP subtype 1H and 3L isolates are identical. The sequence of the 6U gene differs by 13 nucleotides, resulting in 10 amino acid changes.

Bacterial Outer Membrane Proteins↗
PubMed1991

Effects of recombinant methionyl bovine somatotropin (sometribove) in high producing cows milked three times daily.

Effects of daily sometribove administration on milk yield and composition, body condition score, BW, and SCC were evaluated in Holstein cows milked three times daily. Lactating cows (n =104) were assigned randomly to control or sometribove-treated (25 mg/d) groups. The experimental period was 16 wk, consisting of 2-wk pretreatment, 12-wk treatment, and 2-wk posttreatment periods. All cows were injected once daily starting at 53 to 180 d postpartum, housed in free stalls, and fed one of five total mixed rations according to milk production. Body weights were measured weekly, and body condition was scored biweekly. Milk yield was recorded daily, and weekly milk samples were analyzed for fat, protein, lactose, total solids, and SCC. Milk yield and milk protein were increased 18.8% (38.6 vs. 32.5 kg/d) and 3.3% (3.1 vs. 3.0%), respectively, whereas percentage of milk fat, lactose, SNF, SCC, and BW were unaffected by treatment. Overall average body condition scores were lower for the sometribove-treated group versus control (2.2 vs. 2.4). No apparent differences in the number of cows treated for mastitis, foot rot, displaced abomasum, or lameness were observed between treatment groups. Sometribove treatment significantly enhanced milk yield (6.1 kg/d) with no apparent negative effects on health in high producing cows milked three times per day.

Animals↗
PubMed1990

The impact of the amended Ontario Mental Health Act (Bill 7) on patients discharging themselves from hospital against medical advice (AMA): a preliminary study.

Bill 7, the most recent amendment to the Ontario Mental Health Act was introduced in December 1986. It has resulted in some major changes to the practice of psychiatry, especially in provincial hospitals. We compared patients who had discharged themselves against medical advice (AMA) during the six months before the Bill was enacted, with those who discharged themselves AMA in the 12 months following. Significantly more patients discharged themselves AMA in the post- than the pre-Bill period. The majority of these were potentially treatable, acutely ill individuals with schizophrenia or affective disorder. We argue that Bill 7 has largely failed in its objective to improve the overall "quality of care" to psychiatric patients, at least in the short term.

Commitment of Persons with Psychiatric Disorders↗
PubMed1990

Establishing a neonatal resuscitation team in community hospitals.

Recent national guidelines for neonatal resuscitation state that personnel trained in resuscitation skills should be immediately available for every delivery. Meeting this standard is a challenge for small community hospitals with limited staff and few 24-hour in-house physicians. We have developed a strategy for organizing neonatal resuscitation teams in community hospitals and describe our experience with establishing such teams in our region. Suggestions for implementation include: identifying a project organizer, involving all relevant staff in the decision making, writing a formal protocol, and planning a schedule for implementation. Often team members will be nurses or other professionals in expanded roles, the only stipulation being that they be immediately available and well trained. Recommendations are made for training and scheduling of neonatal resuscitation team members and for the contents of the resuscitation protocol. Barriers to successful implementation are discussed, including liability concerns or lack of confidence among team members, nonacceptance of expanded roles by other professionals, and difficulties with scheduling, equipment maintenance, and risk assignment. Nevertheless, successful establishment of a neonatal resuscitation team can effectively reduce the risk of neonatal asphyxia in small community hospitals.

Hospitals, Community↗
PubMed1989

Origin of the autoreactive anti-type II collagen response. II. Specificities, antibody isotypes and usage of V gene families of anti-type II collagen B cells.

Autoantibodies play an important role in the pathogenesis of type II collagen-induced arthritis in mice. We have earlier reported a high frequency of cells producing anti-CII autoantibodies and a low frequency of cells producing multispecific antibodies, in regional lymph nodes 9 to 11 days after primary immunization with CII. It is shown here that anti-CII antibodies produced during primary immune response are IgG-antibodies mainly of IgG2a, IgG1 and IgG2b subclasses while IgM antibodies dominate primary responses elicited by OVA and denatured CII as analyzed with a large panel of hybridomas. Anti-CII antibodies generated during the primary response recognize at least five different epitopes on the CII molecule. The specificities of these antibodies for various epitopes result from combinational association of products encoded by genes derived from various VH and VK families and/or by the occurrence of somatic mutations. It is suggested that the primary anti-CII autoantibody response involves activation of memory B cells and is in this aspect different from the origin of "natural" autoantibodies.

Animals↗
PubMed1989

Diversity of the outer membrane protein P2 gene from major clones of Haemophilus influenzae type b.

In previous studies, it has been demonstrated that outer membrane protein P2 from Haemophilus influenzae type b has porin activity and that antibody directed against P2 is protective in an infant rat bacteraemic model. Outer membrane protein subtyping has been employed to subclassify type b Haemophilus isolates. Strain MinnA has the outer membrane protein subtype 1H and is representative of the dominant clonal group of disease-producing isolates in the United States. In the present study, the P2 gene from strain MinnA was employed to probe EcoRI- and Pvull-digested chromosomal DNA from 24 Haemophilus influenzae type b isolates representative of the common outer membrane protein subtype groups observed throughout the world. Restriction fragment length polymorphisms were identified for the members of the outer membrane protein subtype 3L group, but not for the other subtypes examined. The P2 gene from each of four prototype isolates was then cloned, sequenced and compared to the previously reported sequence of the strain MinnA gene. The P2 gene from each of two isolates with the outer membrane protein subtype 3L was identical to the MinnA P2 sequence. The P2 gene from a subtype 2L isolate differed by a single nucleotide and the gene from a subtype 6U isolate differed by 13 nucleotides. Thus, the P2 protein is highly conserved among type b isolates.

Amino Acid Sequence↗