Localization of the Usher syndrome type ID gene (Ush1D) to chromosome 10

The Usher syndromes (USH) are a group of autosomal recessive diseases characterized by progressive pigmentary retinopathy and sensorineural hearing loss. Five USH genes have been mapped and at least one additional gene is known to exist. By homozygosity mapping in a consanguineous family, a sixth USH gene has been localized. Clinical findings in the four affected children are consistent with established diagnostic criteria for Ush1. Linkage to known USH loci was excluded, and using two genomic DNA pools, one from the affected children and the other from the parents, 161 polymorphic markers evenly spaced across the autosomal human genome were screened. The location of the Ush1D gene was defined by the only region showing homozygosity by descent in the affected siblings, a 15 cM interval on chromosome 10q bounded by D10S529 and D10S573.     

A novel electrochemical heparin sensor

Heparin is one of the most important clinical drugs, and is employed universally during surgical procedures and extra-corporeal therapies to prevent blood from clotting. Its clinical use, however, is often associated with serious hemorrhagic complications. Because of this life threatening bleeding risk, there is a need for a simple sensing device that can rapidly and directly monitor heparin levels during extra-corporeal therapies to provide a safeguard during these procedures. Current heparin assays are all based on the measurement of blood clotting time, and none of them are suitable for direct and rapid determination of heparin. We describe applying conventional ion selective electrode (ISE) polymer membrane technology and using a specifically formulated membrane doped with tridodecylmethylammonium chloride (TDMAC) as the heparin complexing agent, to devise the first electrochemical sensor for heparin measurement. The sensor is capable of detecting directly and rather selectively the free heparin concentrations in both physiologic saline and undiluted plasma samples. In addition, the clinical utility of the sensor has been demonstrated by monitoring the levels of heparin in undiluted whole blood specimens obtained from patients undergoing open heart operations. It is envisioned that the sensor could be configured as an in-line device within extracorporeal blood loops to monitor current extracorporeal therapy, or as a convenient single use disposable device for rapid bedside or laboratory measurements of heparin in small discrete samples of undiluted whole blood. Preliminary studies concerning the feasibility of designing a mass fabricated, solid state, disposable heparin sensor also have been conducted.     

Cervical length at 23 weeks of gestation: relation to demographic characteristics and previous obstetric history

OBJECTIVES: To examine the feasibility of introducing routine measurement of cervical length at 23 weeks of gestation, to establish the distribution of cervical lengths in a routine population of singleton pregnancies and to examine the relation between cervical length and demographic characteristics and previous obstetric history. METHODS: Cervical length was measured by transvaginal sonography at 23 weeks of gestation in women with singleton pregnancies attending for routine antenatal care. The distribution of cervical lengths was established and the significance of differences in median cervical length between subgroups according to maternal age, ethnic origin, maternal ponderal index, cigarette smoking, alcohol drinking, drug abuse and previous obstetric history was calculated. In addition, 100 women were asked to complete a questionnaire aimed to assess the degree of discomfort, pain or embarrassment caused by the scan. In 100 pregnancies, cervical length was measured in each patient by two of four operators to determine intraobserver and interobserver variabilities. RESULTS: During the study period, 2702 (80%) of the 3358 women attending for a 23-week scan agreed to participate in the study and, in all cases, the cervical length was measured successfully. The median cervical length was 38 mm and in 1.6% of cases the length was 15 mm or less. More than 90% of the women reported that the procedure was associated with no or only mild discomfort and embarrassment, whilst 85% found the ultrasound scan to be equally or less uncomfortable than a speculum examination. Measurement of cervical length was highly reproducible and, on 95% of occasions, the difference between two measurements by the same observer and by two observers was < or = 3.5 mm and < or = 4.2 mm, respectively. Cervical length was significantly shorter in women of Afro-Caribbean origin compared to Caucasians, those aged less than 20 years, those with a low ponderal index, those with a history of previous miscarriage or preterm delivery and in drug abusers. CONCLUSIONS: Transvaginal sonographic measurement of cervical length is highly reproducible and it is associated with a minimal degree of discomfort to the patients. At 23 weeks, the median cervical length is 38 mm and, in 1.6% of the population, the length is 15 mm or less. There is an association between cervical length and demographic characteristics and previous obstetric history.     

A comprehensive human linkage map with centimorgan density. Cooperative Human Linkage Center (CHLC)

In the last few years there have been rapid advances in developing genetic maps for humans, greatly enhancing our ability to localize and identify genes for inherited disorders. Through the collaborative efforts of three large groups generating microsatellite markers and the efforts of the 110 CEPH collaborators, a comprehensive human linkage map is presented here. It consists of 5840 loci, of which 970 are uniquely ordered, covering 4000 centimorgans on the sex-averaged map. Of these loci, 3617 are polymerase chain reaction-formatted short tandem repeat polymorphisms, and another 427 are genes. The map has markers at an average density of 0.7 centimorgan, providing a resource for ready transference to physical maps and achieving one of the first goals of the Human Genome Project--a comprehensive, high-density genetic map.     

Oestrogenic, anti-oestrogenic and fertility effects of some triphenylethanes and triphenylethylenes related to ethamoxytriphetol (MER 25)

The myocardial content of digoxin 60 min after intravenous administration in open-chest dogs correlated with heart rate controlled in individual dogs between 64 and 215 beats/min. In other dogs, increasing right ventricular mechanical work by constriction of the pulmonary artery resulted in greater right ventricular digoxin uptake. Increase in myocardial blood flow per se could not explain these findings since, in further dogs, increasing regional myocardial blood flow by adenosine infusion did not much affect digoxin uptake. Active uptake of cardiac glycosides is probably influenced by myocardial mechanical and metabolic activity.     

Thermal spreading of MoO3 in H–ZY

This work provides a structural, optical and kinetics approach to the molybdenum oxo-species formed during thermally driven migration on H–ZY starting from mechanical mixtures with MoO₃. The samples were characterized as a function of time of treatment by UV–vis diffuse reflectance, X-ray diffraction, N₂ adsorption and scanning transmission electron microscopy (STEM). Local analysis of elemental compositions obtained from linear scan of characteristic X-ray signal show a direct evidence of molybdenum presence into the zeolite crystals. Ultraviolet absorption spectra were used to determine both the kinetics of the spreading and the speciation of MoO_x in the H–ZY. Besides MoO₃, three surface molybdenum oxo-species were identified according to the edge energy (E_g) values of bulk molybdenum oxide reference compounds. This study shows that the tetrahedral species prevailed on H–ZY. This is consistent with limitations in the migration and growth of MoO_x in the channel structure of the zeolite. Kinetic study suggest that migration of MoO_x in the H–ZY at low temperature (ca. 723 K) occurs across the formation and diffusion of hydrated species such as MoO₂(OH)₂, which interact with the zeolite and form monomeric and dimeric structures (like (MoO₄)²⁻ and (Mo₂O₇)²⁻). Migration of MoO_x species in the H–ZY studied is significant even at 723 K and after very short periods of treatment (<5 min).     

phnE and glpT genes enhance utilization of organophosphates in Escherichia coli K-12

Wild-type Escherichia coli K-12 strain JA221 grows poorly on low concentrations (< or = 1 mM) of diisopropyl fluorophosphate and its hydrolysis product, diisopropyl phosphate (DIPP), as sole phosphorus sources. Spontaneous organophosphate utilization (OPU) mutants were isolated that efficiently utilized these alternate sources of phosphate. A genomic library was constructed from one such OPU mutant, and two genes were isolated that conferred the OPU phenotype to strain JA221 upon transformation. These genes were identified as phnE and glpT. The original OPU mutation represented phnE gene activation and corresponded to the same 8-bp unit deletion from the cryptic wild-type E. coli K-12 phnE gene that has been shown previously to result in phnE activation. In comparison, sequence analysis revealed that the observed OPU phenotype conferred by the glpT gene was not the result of a mutation. PCR clones of glpT from both the mutant and the wild type were found to confer the OPU phenotype to JA221 when they were present on the high-copy-number pUC19 plasmid but not when they were present on the low-copy-number pWSK29 plasmid. This suggests that the OPU phenotype associated with the glpT gene is the result of amplification and overproduction of the glpT gene product. Both the active phnE and multicopy glpT genes facilitated effective metabolism of low concentrations of DIPP, whereas only the active phnE gene could confer the ability to break down a chromogenic substrate, 5-bromo-4-chloro-3-indoxyl phosphate-p-toluidine (X-Pi). This result indicates that in E. coli, X-Pi is transported exclusively by the Phn system, whereas DIPP (or its metabolite) may be transported by both Phn and Glp systems.