Initial metal-metal bond breakage detected by fs X-ray scattering in the photolysis of Ru3(CO)12 in cyclohexane at 400 nm.

Using femtosecond resolution X-ray solution scattering at a free electron laser we were able to directly observe metal-metal bond cleavage upon photolysis at 400 nm of Ru3(CO)12, a prototype for the photochemistry of transition metal carbonyls. This leads to the known single intermediate Ru3(CO)11(µ-CO)*, with a bridging ligand (µCO) and where the asterisk indicates an open Ru3-ring. This loses a CO ligand on a picosecond time scale yielding a newly observed triple bridge intermediate, Ru3(CO)8(µ-CO)3*. This loses another CO ligand to form the previously observed Ru3(CO)10, which returns to Ru3(CO)12via the known single-bridge Ru3(CO)10(µ-CO). These results indicate that contrary to long standing hypotheses, metal-metal bond breakage is the only chemical reaction immediately following the photolysis of Ru3(CO)12 at 400 nm. Combined with previous picosecond resolution X-ray scattering data and time resolved infrared spectroscopy these results yield a new mechanism for the photolysis of Ru3(CO)12.

Microduplications encompassing the Sonic hedgehog limb enhancer ZRS are associated with Haas-type polysyndactyly and Laurin-Sandrow syndrome.

Laurin-Sandrow syndrome (LSS) is a rare autosomal dominant disorder characterized by polysyndactyly of hands and/or feet, mirror image duplication of the feet, nasal defects, and loss of identity between fibula and tibia. The genetic basis of LSS is currently unknown. LSS shows phenotypic overlap with Haas-type polysyndactyly (HTS) regarding the digital phenotype. Here we report on five unrelated families with overlapping microduplications encompassing the Sonic hedgehog (SHH) limb enhancer ZPA regulatory sequence (ZRS) on chromosome 7q36. Clinically, the patients show polysyndactyly phenotypes and various types of lower limb malformations ranging from syndactyly to mirror image polydactyly with duplications of the fibulae. We show that larger duplications of the ZRS region (>80 kb) are associated with HTS, whereas smaller duplications (<80 kb) result in the LSS phenotype. On the basis of our data, the latter can be clearly distinguished from HTS by the presence of mirror image polysyndactyly of the feet with duplication of the fibula. Our results expand the clinical phenotype of the ZRS-associated syndromes and suggest that smaller duplications (<80 kb) are associated with a more severe phenotype. In addition, we show that these small microduplications within the ZRS region are the underlying genetic cause of Laurin-Sandrow syndrome.

Genetic heterogeneity in Pakistani microcephaly families.

Autosomal recessive primary microcephaly (MCPH) is caused by mutations in at least eight different genes involved either in cell division or DNA repair. Most mutations are identified in consanguine families from Pakistan, Iran and India. To further assess their genetic heterogeneity and mutational spectra, we have analyzed 57 consanguine Pakistani MCPH families. In 34 MCPH families, we detected linkage to five out of the eight well-characterized disease loci and identified mutations in 27 families, leaving seven families without mutations in the coding exons of the presumably underlying MCPH genes. In the MCPH cohort 23 families could not be linked to any of the known loci, pointing to remarkable locus heterogeneity. The majority of mutations were found in ASPM followed by WDR62, CENPJ, CEP152 and MCPH1. One ASPM mutation (p.Trp1326*) was found in as many as eight families suggesting a Pakistani founder mutation. One third of the families were linked to ASPM followed by WDR62 confirming previous data. We identified three novel ASPM mutations, four novel WDR62 mutations, one novel MCPH1 mutation and two novel CEP152 mutations. CEP152 mutations have not been described before in the Pakistani population.

Guest-host interactions investigated by time-resolved X­ray spectroscopies and scattering at MHz rates: solvation dynamics and photoinduced spin transition in aqueous Fe(bipy)3(2+).

We have studied the photoinduced low spin (LS) to high spin (HS) conversion of [Fe(bipy)(3)](2+) in aqueous solution. In a laser pump/X-ray probe synchrotron setup permitting simultaneous, time-resolved X-ray diffuse scattering (XDS) and X-ray spectroscopic measurements at a 3.26 MHz repetition rate, we observed the interplay between intramolecular dynamics and the intermolecular caging solvent response with better than 100 ps time resolution. On this time scale, the initial ultrafast spin transition and the associated intramolecular geometric structure changes are long completed, as is the solvent heating due to the initial energy dissipation from the excited HS molecule. Combining information from X-ray emission spectroscopy and scattering, the excitation fraction as well as the temperature and density changes of the solvent can be closely followed on the subnanosecond time scale of the HS lifetime, allowing the detection of an ultrafast change in bulk solvent density. An analysis approach directly utilizing the spectroscopic data in the XDS analysis effectively reduces the number of free parameters, and both combined permit extraction of information about the ultrafast structural dynamics of the caging solvent, in particular, a decrease in the number of water molecules in the first solvation shell is inferred, as predicted by recent theoretical work.

Comparative performance of obstetric comorbidity indices within categories of race and ethnicity: an external validation study.

BACKGROUND: Existing obstetric comorbidity adjustment indices were created without explicitly accounting for sociodemographic diversity in the development populations, which could lead to imprecise estimates if these indices are applied to populations different from the ones in which they were developed. The objective of this study was to validate two obstetric comorbidity indices (one using severe maternal morbidity [SMM] and one using end-organ injury or mortality) within categories of race/ethnicity. METHODS: Delivery hospitalizations from the State Inpatient Databases for Florida, Maryland, Kentucky, Washington (2015-2018) and New York (2015-2016) were analyzed. Outcomes were modeled using logistic regression by category of race/ethnicity and overall, with each model having its respective index value as the covariate. Discrimination and calibration were assessed. RESULTS: There were 1 604 203 delivery hospitalizations, among which 1.6% experienced SMM and 0.4% had SMM excluding blood transfusions. Maternal end-organ injury or mortality was identified in 0.5% of cases. For the entire patient population, the area under the receiver operating curve (AUROC) was 0.72 (95% CI 0.71 to 0.72) and 0.75 (95% CI 0.75 to 0.76) for SMM and non-transfusion SMM, respectively. The AUROC for maternal end-organ injury or death was 0.65 (95% CI 0.65 to 0.66). All scores exhibited poor calibration across racial/ethnic groups. There was no substantial variation within categories of race/ethnicity in terms of index performance. CONCLUSION: Users of these indices should consider performance data in totality when choosing a measure for obstetric comorbidity adjustment. There were no marked differences in model performance observed across race/ethnicity groups within each index.

Obstructive sleep apnea is associated with adverse maternal outcomes using a United States multistate database cohort, 2007-2014.

BACKGROUND: Obstructive sleep apnea affects approximately 11% of women of reproductive age, although it is often undetected and untreated. Previous studies suggest an association between obstructive sleep apnea and adverse maternal outcomes. Herein, we aim to better characterize the relationship between obstructive sleep apnea and maternal outcomes. METHODS: Using the State Inpatient Databases, we performed a retrospective analysis of parturients ≥18 years old having inpatient deliveries in Florida, New York, California, Maryland, and Kentucky from 2007 to 2014. Outcomes included maternal pre-existing conditions, in-hospital mortality, maternal-fetal conditions and complications, and hospital length of stay >5 days. RESULTS: Our cohort consisted of 6 911 916 parturients of whom 4326 (0.06%) had obstructive sleep apnea. Women with obstructive sleep apnea were more likely to present with pre-existing conditions, such as obesity and pre-pregnancy diabetes. After adjusting for patient- and hospital-level confounders in our multivariate analysis, obstructive sleep apnea status was associated with an increased odds of maternal-fetal conditions and complications, including pre-eclampsia (aOR 2.05, 95% CI 1.87 to 2.26), pulmonary edema (aOR 4.73, 95% CI 2.84 to 7.89), cesarean delivery (aOR 1.96, 95% CI 1.81 to 2.11), early onset delivery (aOR 1.28, 95% CI 1.17 to 1.40), and length of stay >5 days (aOR 2.42, 95% CI 2.21 to 2.65). Obstructive sleep apnea was not significantly associated with a higher risk of in-hospital mortality. CONCLUSIONS: Pregnant women with obstructive sleep apnea have a significantly higher adjusted risk of adverse maternal outcomes compared with women without obstructive sleep apnea.

Crystallinity of the double layer of cadmium arachidate films at the water surface.

A crystalline counterionic layer at the interface between an electrolyte solution and a charged layer of insoluble amphiphilic molecules was observed with grazing incidence synchrotron x-ray diffraction. Uncompressed arachidic films spread over 10(-3) molar cadmium chloride solution (pH 8.8) spontaneously form crystalline clusters with coherence lengths of approximately 1000 angstroms at 9 degrees C. Ten distinct diffraction peaks were observed, seven of which were attributed to scattering only from a crystalline Cd(2+) layer and the other three to scattering primarily from the arachidate layer. The reflections from the Cd(2+) layer were indexed according to a 2 x 3 supercell of the arachidate lattice with three Cd(2+) ions per cadmium unit cell.

A Synchrotron X-ray Study of a Solid-Solid Phase Transition in a Two-Dimensional Crystal.

A measurement and interpretation on a molecular level of a phase transition in an ordered Langmuir monolayer is reported. The diagram of surface pressure (pi) versus molecular area of a monolayer of chiral (S)-[CF(3)-(CF(2))(9)-(CH(2))(2)-OCO-CH(2)-CH (NH(3)(+))CO(2)(-)] over water shows a change in slope at about pi(s)= 25 millinewtons per meter. Grazing-incidence x-ray diffraction and specular reflectivity measurements indicate a solid-solid phase transition at pi(s). The diffraction pattren at low pressures reveals two diffraction peaks of equal intensities, with lattice spacings d of 5.11 and 5.00 angstroms; these coalesce for pi >/=pi(s). Structural models that fit the diffraction data show that at pi> pi(s) the molecules pack in a two-dimensional crystal with the molecules aligned vertically. At pi < pi(s) there is a molecular tilt of 16 degrees +/- 7 degrees . Independent x-ray reflectivity data yield a tilt of 26 degrees +/- 7 degrees . Concomitant with the tilt, the diffraction data indicate a transition from a hexagonal to a distorted-hexagonal lattice. The hexagonal arrangement is favored because the -(CF(2))(9)CF(3) moiety adopts a helical conformation. Compression to 70 millinewtons per meter yields a unit cell with increased crystallinity and a coherence length exceeding 1000 angstroms.

Control of structure and growth of polymorphic crystalline thin films of amphiphilic molecules on liquid surfaces.

The spontaneous formation and coexistence of crystalline polymorphic trilayer domains in amphiphilic films at air-liquid interfaces is demonstrated by grazing incidence synchrotron x-ray diffraction. These polymorphic crystallites may serve as models for the early stages of crystal nucleation and growth, helping to elucidate the manner in which additives influence the progress of crystal nucleation, growth, and polymorphism and suggesting ways of selectively generating and controlling multilayers on liquid surfaces. Auxiliary molecules have been designed to selectively inhibit development of the polymorphs, leading primarily to a single phase monolayer.

Langmuir-blodgett films of a functionalized molecule with cross-sectional mismatch between head and tail.

A functionalized surfactant has been investigated as floating monolayers by synchrotron x-ray diffraction and as bilayers transferred to solid supports by the Langmuir-Blodgett technique through atomic force microscopy. The transfer process is accompanied by an increase of the unit cell area (about 17 percent) and by an increase of the average domain diameter of nanometer-scale domains (about three times). The unit cell area of the floating monolayer corresponds to close packing of the head groups and a noncharacteristic packing of the tifted alkyl chains. The larger unit cell area of the bilayer film is consistent with a particular ordered packing of the alkyl chains, leaving free space for the head groups.

Hydrated cholesterol: phospholipid domains probed by synchrotron radiation.

X-ray scattering experiments on mixed films of cholesterol and phospholipids at air-water and Si solid-water interfaces were undertaken to glean information on pathological crystallization of cholesterol bilayers. Grazing-incidence X-ray diffraction patterns at the air-water interface of various cholesterol:dipalmitoyl-phosphatidylcholine (Ch:DPPC) monolayer mixtures compressed beyond monolayer collapse yielded the established 10 x 7.5 Ų Ch bilayer motif, for Ch:DPPC molar ratios higher than 2.5:1. Attempts to obtain a diffraction signal from various Ch:phospholipid film mixtures at the Si solid-water interface, indicative of the presence of the Ch bilayer motif, were unsuccessful. Only after removal of sufficient water from the cell was a weak diffraction signal obtained suggestive of a cholesterol film two bilayers thick. Off-specular X-ray reflectivity measurements made on a 1.75:1 mixture of Ch and bovine cardiac phosphatidylcholine (BCPC) deposited as a bilayer on a Si wafer and placed in a cell filled with water yielded positive results. The derived electron density profile showed the presence of a bilayer mixture consistent with a phase separation of cholesterol and BCPC, and possible formation of a crystalline cholesterol bilayer within the hydrated mixed bilayer, but not a proof thereof.

A mutation in the receptor binding site of GDF5 causes Mohr-Wriedt brachydactyly type A2.

BACKGROUND: Brachydactyly type A2 (OMIM 112600) is characterised by hypoplasia/aplasia of the second middle phalanx of the index finger and sometimes the little finger. BDA2 was first described by Mohr and Wriedt in a large Danish/Norwegian kindred and mutations in BMPR1B were recently demonstrated in two affected families. METHODS: We found and reviewed Mohr and Wriedt's original unpublished annotations, updated the family pedigree, and examined 37 family members clinically, and radiologically by constructing the metacarpo-phalangeal profile (MCPP) pattern in nine affected subjects. Molecular analyses included sequencing of BMPR1B, linkage analysis for STS markers flanking GDF5, sequencing of GDF5, confirmation of the mutation by a restriction enzyme assay, and localisation of the mutation inferred from the very recently reported GDF5 crystal structure, and by superimposing the GDF5 protein sequence onto the crystal structure of BMP2 bound to Bmpr1a. RESULTS: A short middle phalanx of the index finger was found in all affected individuals, but other fingers were occasionally involved. The fourth finger was characteristically spared. This distinguishes Mohr-Wriedt type BDA2 from BDA2 caused by mutations in BMPR1B. An MCPP analysis most efficiently detected mutation carrier status. We identified a missense mutation, c.1322T>C, causing substitution of a leucine with a proline at amino acid residue 441 within the active signalling domain of GDF5. The mutation was predicted to reside in the binding site for BMP type 1 receptors. CONCLUSION: GDF5 is a novel BDA2 causing gene. It is suggested that impaired activity of BMPR1B is the molecular mechanism responsible for the BDA2 phenotype.

Breakpoints around the HOXD cluster result in various limb malformations.

BACKGROUND: Characterisation of disease associated balanced chromosome rearrangements is a promising starting point in the search for candidate genes and regulatory elements. METHODS: We have identified and investigated three patients with limb abnormalities and breakpoints involving chromosome 2q31. Patient 1 with severe brachydactyly and syndactyly, mental retardation, hypoplasia of the cerebellum, scoliosis, and ectopic anus, carries a balanced t(2;10)(q31.1;q26.3) translocation. Patient 2, with translocation t(2;10)(q31.1;q23.33), has aplasia of the ulna, shortening of the radius, finger anomalies, and scoliosis. Patient 3 carries a pericentric inversion of chromosome 2, inv(2)(p15q31). Her phenotype is characterised by bilateral aplasia of the fibula and the radius, bilateral hypoplasia of the ulna, unossified carpal bones, and hypoplasia and dislocation of both tibiae. RESULTS: By fluorescence in situ hybridisation, we have mapped the breakpoints to intervals of approximately 170 kb or less. None of the three 2q31 breakpoints, which all mapped close to the HOXD cluster, disrupted any known genes. CONCLUSIONS: Hoxd gene expression in the mouse is regulated by cis-acting DNA elements acting over distances of several hundred kilobases. Moreover, Hoxd genes play an established role in bone development. It is therefore very likely that the three rearrangements disturb normal HOXD gene regulation by position effects.

Distinct CDH3 mutations cause ectodermal dysplasia, ectrodactyly, macular dystrophy (EEM syndrome).

BACKGROUND: EEM syndrome is the rare association of ectodermal dysplasia, ectrodactyly, and macular dystrophy. METHODS: We here demonstrate through molecular analysis that EEM is caused by distinct homozygous CDH3 mutations in two previously published families. RESULTS: In family 1, a missense mutation (c.965A-->T) causes a change of amino acid 322 from asparagine to isoleucine; this amino acid is located in a highly conserved motif likely to affect Ca2+ binding affecting specificity of the cell-cell binding function. In family 2, a homozygous frameshift deletion (c.829delG) introduces a truncated fusion protein with a premature stop codon at amino acid residue 295, expected to cause a non-functional protein lacking both its intracellular and membrane spanning domains and its extracellular cadherin repeats 3-5. Our mouse in situ expression data demonstrate that Cdh3 is expressed in the apical ectodermal ridge from E10.5 to E12.5, and later in the interdigital mesenchyme, a pattern compatible with the EEM phenotype. Furthermore, we discuss possible explanations for the phenotypic differences between EEM and congenital hypotrichosis with juvenile macular dystrophy (HJMD), which is also caused by CDH3 mutations. CONCLUSIONS: In summary, we have ascertained a third gene associated with ectrodactyly and have demonstrated a hitherto unrecognised role of CDH3 in shaping the human hand.

X-ray diffraction from a single layer of purple membrane at the air/water interface.

X-ray diffraction patterns have been recorded from a single layer of purple membrane ( approximately 50 A thickness) at the air/water interface in a Langmuir trough. Grazing-incidence X-ray diffraction is demonstrated to be a promising method for obtaining structural information on membrane proteins under physiological conditions. The method is so sensitive that diffraction can be measured from samples with only 10(13) protein molecules in the beam. Diffraction from hexagonal crystals of purple membrane with a lattice constant of 61. 3 A was observed up to the order {h,k}={4,3}, corresponding to a resolution of approximately 9 A. The work reported here is a first step towards a new way of protein crystallography using grazing-incidence X-ray diffraction at the air/water interface.

Brain serotonin1A receptor binding measured by positron emission tomography with [11C]WAY-100635: effects of depression and antidepressant treatment.

BACKGROUND: Pharmacological and postmortem investigations suggest that patients with major depressive disorder have alterations in function or density of brain serotonin1A (5-HT1A) receptors. The aim of the present study was to use positron emission tomography with the selective 5-HT1A receptor antagonist [11C]WAY-100635 to measure 5-HT1A receptor binding in depressed patients before and during treatment with selective serotonin reuptake inhibitors. METHODS: Positron emission tomographic scans with [11C]WAY-100635 were performed on 25 patients with major depressive disorder. These included 15 unmedicated depressed patients. Ten of these unmedicated patients were scanned again during selective serotonin reuptake inhibitor treatment. A further 10 patients with major depressive disorder were scanned on one occasion only while taking selective serotonin reuptake inhibitors. Comparisons were made with [11C]WAY-100635 positron emission tomographic scans in 18 healthy volunteer subjects. Region of interest analysis and statistical parametric mapping were performed on binding potential images generated using a reference tissue model. RESULTS: Binding potential values were reduced across many of the regions examined, including frontal, temporal, and limbic cortex in both unmedicated and medicated depressed patients compared with healthy volunteers. Binding potential values in medicated patients were similar to those in unmedicated patients. CONCLUSIONS: Major depressive disorder is associated with a widespread reduction in 5-HT1A receptor binding. This reduced 5-HT1A receptor binding was not changed by selective serotonin reuptake inhibitor treatment.

Neutron and X-ray scattering studies of cholera toxin interactions with lipid monolayers at the air-liquid interface.

Using neutron/X-ray reflectivity and X-ray grazing incidence diffraction (GID), we have characterized the structure of mixed DPPE:GM(1) lipid monolayers before and during the binding of cholera toxin (CTAB(5)) or its B subunit (CTB(5)). Structural parameters such as the density and thickness of the lipid layer, extension of the GM(1) oligosaccharide headgroup, and orientation and position of the protein upon binding are reported. Both CTAB(5) and CTB(5) were measured to have approximately 50% coverage when bound to the lipid monolayer. X-ray GID experiments show that both the lipid monolayer and the cholera toxin layer are crystalline. The effects of X-ray beam damage have been assessed and the monolayer/toxin structure does not change with time after protein binding has saturated.

Contraception in women with IDDM. An epidemiological study.

OBJECTIVE: To study whether suitable contraceptive methods to women with diabetes mellitus in fact are applied. RESEARCH DESIGN AND METHODS: A questionnaire survey on the use of contraceptives in all 18-to-49-yr-old women (n = 261) with IDDM in Funen County, Denmark, and an age-comparable control group, (n = 287) was performed. Data were collected from 1987 to 1990. Response was achieved from 94% diabetic women and 88% control subjects. RESULTS: The overall use of contraception in diabetic women (77.1%) was almost identical to that of control subjects (73.6%). Compared with control subjects, significantly fewer diabetic women were using the OCP (P < 0.005) and partner sterilization (P < 0.05), whereas more diabetic women were sterilized (P < 0.0005). Among diabetic contraceptive users, the IUD, female sterilization, condoms, and the OCP each accounted for roughly 20%. Diabetic women using the OCP were predominantly young, and most had never been pregnant; approximately 20% of them used high-dose formulations. Sterilization was frequently used by older diabetic women, and most of these women had 2 or more children; 27% of the diabetic women using an IUD were nulligravidae. Further, 18% used a method with an unsuitable high failure rate. CONCLUSIONS: Our study demonstrates that diabetic women are not sufficiently advised concerning use of contraception.

Epidemiology of menarche and menstrual disturbances in an unselected group of women with insulin-dependent diabetes mellitus compared to controls.

To describe the age at menarche and the prevalence of menstrual disturbances in an unselected group of women with insulin-dependent diabetes mellitus compared to controls, we identified all women having debut of diabetes mellitus before the age of 30 yr and living in the County of Funen, Denmark on July 1, 1987 and being between 18 and 49 yr old. The women received a structured questionnaire inquiring information concerning menstrual conditions. An age comparable group of nondiabetic women was used as controls; 245 (94%) diabetic women and 253 (88%) controls answered the questionnaire. Among women with debut of diabetes before the age of 10 yr, the age at menarche was delayed 1 yr when comparing to controls (P less than 0.0001). During the past 6 months before answering the questionnaire, 8.2% of the diabetic women and 2.8% of the controls had experienced episodes of secondary amenorrhea (P less than 0.01). Corresponding figures for oligomenorrhea were 10.6% and 4.8% (P less than 0.02), for polymenorrhea 7.3% and 5.2% (NS), and for all types of menstrual disturbances 21.6% and 10.8%, respectively (P less than 0.005). Episodes of secondary amenorrhea occurring more than 6 months before answering the questionnaire had been experienced by 10.7% of the diabetic population vs. 4.8% of the controls (P less than 0.05); corresponding figures for primary amenorrhea were 4.9% and 1.2%, respectively (P less than 0.05). We conclude that the age at menarche among women having developed insulin-dependent diabetes mellitus before the age of 10 yr was delayed by 1 yr when compared to controls. The overall prevalence of menstrual disturbances is increased in diabetic women compared to nondiabetic controls.