Prenatal diagnosis and genetic analysis of X chromosome polysomy 49, XXXXY

We report on the prenatal diagnosis, genetic analysis and clinical manifestations of a 49,XXXXY fetus. A 31-year-old, primigravida woman was referred for genetic counselling at 17 weeks' gestation with the sonographic findings of intrauterine growth retardation, generalized oedema, a large septated cystic hygroma colli measuring 5x4 cm, and abnormal posturing of the lower extremities. Quantitative fluorescent polymerase chain reaction (QF-PCR) with small tandem repeat (STR) markers specific for chromosome X and a pentanucleotide marker X22 for the Xq/Yq pseudoautosomal region PAR2 rapidly detected the X-chromosome polysomy from amniotic fluid cells. This abnormality appeared to arise from successive non-disjunction during maternal meiosis I and meiosis II. Cytogenetic analysis revealed a karyotype of 49,XXXXY. Our case shows that a 49,XXXXY fetus in the second trimester may demonstrate hydrops fetalis and a large septated cystic hygroma colli by prenatal ultrasound. Our case also shows that QF-PCR assays with sex chromosome specific STR markers provide rapid prenatal diagnosis of numerical sex chromosome aneuploidy as well as its genetic cause in fetal cystic hygroma.

Tomographic 3D reconstruction of quick-frozen, Ca2+-activated contracting insect flight muscle

Motor actions of myosin were directly visualized by electron tomography of insect flight muscle quick-frozen during contraction. In 3D images, active cross-bridges are usually single myosin heads, bound preferentially to actin target zones sited midway between troponins. Active attached bridges (approximately 30% of all heads) depart markedly in axial and azimuthal angles from Rayment's rigor acto-S1 model, one-third requiring motor domain (MD) tilting on actin, and two-thirds keeping rigor contact with actin while the light chain domain (LCD) tilts axially from approximately 105 degrees to approximately 70 degrees. The results suggest the MD tilts and slews on actin from weak to strong binding, followed by swinging of the LCD through an approximately 35 degrees axial angle, giving an approximately 13 nm interaction distance and an approximately 4-6 nm working stroke.

Interaction and functional cooperation of PEBP2/CBF with Smads. Synergistic induction of the immunoglobulin germline Calpha promoter

Smads are signal transducers for members of the transforming growth factor-beta (TGF-beta) superfamily. Upon ligand stimulation, receptor-regulated Smads (R-Smads) are phosphorylated by serine/threonine kinase receptors, form complexes with common-partner Smad, and translocate into the nucleus, where they regulate the transcription of target genes together with other transcription factors. Polyomavirus enhancer binding protein 2/core binding factor (PEBP2/CBF) is a transcription factor complex composed of alpha and beta subunits. The alpha subunits of PEBP2/CBF, which contain the highly conserved Runt domain, play essential roles in hematopoiesis and osteogenesis. Here we show that three mammalian alpha subunits of PEBP2/CBF form complexes with R-Smads that act in TGF-beta/activin pathways as well as those acting in bone morphogenetic protein (BMP) pathways. Among them, PEBP2alphaC/CBFA3/AML2 forms a complex with Smad3 and stimulates transcription of the germline Ig Calpha promoter in a cooperative manner, for which binding of both factors to their specific binding sites is essential. PEBP2 may thus be a nuclear target of TGF-beta/BMP signaling.

Prenatal diagnosis of a fetus with distal 10q trisomy

Distal 10q trisomy is a well-defined but rare syndrome. Most cases are diagnosed in infancy or in childhood and rarely include prenatal findings. We present a case of fetal distal 10q trisomy with abnormal prenatal sonographic findings. A 19-year-old primigravida was referred for genetic counselling at 18 gestational weeks because her husband had a familial history of congenital anomalies. Genetic amniocentesis was thus performed and showed fetal distal 10q trisomy (10q24.1-->qter), 46,XX,der(22)t(10;22)(q24.1;p11.2)pat, resulting from paternal t(10;22) reciprocal translocation. Level II ultrasonograms further demonstrated bilateral hydronephrosis, ventricular septal defect and facial dysmorphism ascertained by three-dimensional ultrasound. The pregnancy was terminated at 22 gestational weeks. Post-mortem autopsy confirmed the sonographic findings. We suggest that abnormal prenatal sonographic findings such as cardio-vascular, renal and facial malformations should alert cytogeneticists to search for subtle chromosomal abnormalities.

A WW domain-containing yes-associated protein (YAP) is a novel transcriptional co-activator

A protein module called the WW domain recognizes and binds to a short oligopeptide called the PY motif, PPxY, to mediate protein-protein interactions. The PY motif is present in the transcription activation domains of a wide range of transcription factors including c-Jun, AP-2, NF-E2, C/EBPalpha and PEBP2/CBF, suggesting that it plays an important role in transcriptional activation. We show here that mutation of the PY motif in the subregion of the activation domain of the DNA-binding subunit of PEBP2, PEBP2alpha, abolishes its transactivation function. Using yeast two-hybrid screening, we demonstrate that Yes-associated protein (YAP) binds to the PY motif of PEBP2alpha through its WW domain. The C-terminal region of YAP fused to the DNA-binding domain of GAL4 showed transactivation as strong as that of GAL4-VP16. Exogenously expressed YAP conferred transcription-stimulating activity on the PY motif fused to the GAL4 DNA-binding domain as well as to native PEBP2alpha. The osteocalcin promoter was stimulated by exogenous PEBP2alphaA and a dominant negative form of YAP strongly inhibited this activity, suggesting YAP involvement in this promoter activity in vivo. These results indicate that the PY motif is a novel transcription activation domain that functions by recruiting YAP as a strong transcription activator to target genes.

The capacity of polyomavirus enhancer binding protein 2alphaB (AML1/Cbfa2) to stimulate polyomavirus DNA replication is related to its affinity for the nuclear matrix

The nuclear matrix is thought to play an important role in the DNA replication of eukaryotic cells, although direct evidence for such a role is still lacking. A nuclear matrix-associated transcription factor, polyomavirus (Py) enhancer binding protein 2alphaB1 (PEBP2alphaB1) (AML1/Cbfa2), was found to stimulate Py replication through its cognate binding site. The minimal replication activation domain (RAD) was identified between amino acid (aa) 302 and aa 371 by using a fusion protein containing the GAL4 DNA binding domain (GAL4-RAD). In addition, the region showed affinity for the nuclear matrix and, on the basis of competition studies, binding activity for one or more proteins involved in the initiation of Py DNA replication. A leukemogenic chimeric protein, AML1/ETO(MTG8), which does not contain this region of PEBP2alphaB1/AML1, was also localized in the nuclear matrix fraction and competed for nuclear matrix association with PEBP2alphaB1 and GAL4-RAD. Moreover, AML1/ETO inhibited Py DNA replication stimulated by PEBP2alphaB1 and GAL4-RAD. The inhibition was specific for replication mediated by PEBP2alphaB1 and GAL4-RAD, and proportional to the degree of loss of these activators from the nuclear matrix, suggesting a requirement for nuclear matrix targeting in the stimulation of Py DNA replication by RAD. These results are the first to suggest a molecular link between the initiation of DNA replication and the nuclear matrix compartment.

Prenatal diagnosis of de novo interstitial 16q deletion in a fetus associated with sonographic findings of prominent coronal sutures, a prominent frontal bone, and shortening of the long bones

De novo interstitial 16q deletion diagnosed in utero has not previously been reported. We present a case of fetal de novo interstitial 16q deletion associated with the sonographic findings of prominent coronal sutures, a prominent frontal bone, and shortening of the long bones. Genetic amniocentesis at 23 weeks' gestation revealed a de novo deletion of 16q13-q22. At birth, the fetus manifested a dysmorphic phenotype correlated with monosomy 16q syndrome. Linkage analysis of the family confirmed the maternal origin and the extent of the deletion. We suggest that prenatal detection of a prominent frontal bone with prominent cranial sutures and shortening of the long bones should prompt cytogenetic analysis looking for a deletion in the long arm of chromosome 16.

Intrinsic transcriptional activation-inhibition domains of the polyomavirus enhancer binding protein 2/core binding factor alpha subunit revealed in the presence of the beta subunit

A member of the polyomavirus enhancer binding protein 2/core binding factor (PEBP2/CBF) is composed of PEBP2 alphaB1/AML1 (as the alpha subunit) and a beta subunit. It plays an essential role in definitive hematopoiesis and is frequently involved in the chromosomal abnormalities associated with leukemia. In the present study, we report functionally separable modular structures in PEBP2 alphaB1 for DNA binding and for transcriptional activation. DNA binding through the Runt domain of PEBP2 alphaB1 was hindered by the adjacent carboxy-terminal region, and this inhibition was relieved by interaction with the beta subunit. Utilizing a reporter assay system in which both the alpha and beta subunits are required to achieve strong transactivation, we uncovered the presence of transcriptional activation and inhibitory domains in PEBP2 alphaB1 that were only apparent in the presence of the beta subunit. The inhibitory domain keeps the full transactivation potential of full-length PEBP2 alphaB1 below its maximum potential. Fusion of the transactivation domain of PEBP2 alphaB1 to the yeast GAL4 DNA-binding domain conferred transactivation potential, but further addition of the inhibitory domain diminished the activity. These results suggest that the activity of the alpha subunit as a transcriptional activator is regulated intramolecularly as well as by the beta subunit. PEBP2 alphaB1 and the beta subunit were targeted to the nuclear matrix via signals distinct from the nuclear localization signal. Moreover, the transactivation domain by itself was capable of associating with the nuclear matrix, which implies the existence of a relationship between transactivation and nuclear matrix attachment.

Prenatal diagnosis of de novo isochromosome 13q associated with microcephaly, alobar holoprosencephaly and cebocephaly in a fetus

We report on the prenatal diagnosis, genetic studies, and pathology of a case with de novo isochromosome 13q. A 31-year-old primigravida was referred for genetic counselling at 26 weeks' gestation due to the sonographic findings of intrauterine growth retardation and microcephaly. Level II ultrasonograms further demonstrated alobar holoprosencephaly, hypotelorism, polydactyly, a ventricular septal defect, and a single nostril. A diagnosis of cebocephaly was made. Genetic amniocentesis and cord blood sampling revealed translocation trisomy 13 with a de novo t(13q13q) rearrangement. Chromosomal analysis using G- and C-banding techniques and fluorescence in situ hybridization (FISH) showed an apparent monocentric isochromosome. Molecular analyses using polymorphic molecular markers showed that the rearrangement was consistent with an isochromosome of maternal chromosome 13q[46,XX,i(13)(q10)]. Necropsy confirmed cebocephaly and the prenatally detected anomalies.

Prenatal diagnosis of de novo proximal interstitial deletion of 14q associated with cebocephaly

We report on the prenatal diagnosis of a case of cebocephaly, alobar holoprosencephaly, and microcephaly associated with a de novo proximal interstitial deletion of the long arm of chromosome 14: del(14)(q13q21.1) or (q13q21.2). This is the third case of holoprosencephaly in association with a deletion in this region. The present report concerns the association between prenatal craniofacial development, a holoprosencephaly locus, and the chromosomal segment 14q13.

Measurement of polyethylene wear in cementless total hip arthroplasty

We made a clinical study of polyethylene wear in 240 hips of 187 patients having primary total hip arthroplasties from 1989 to 1990, using uncemented Osteonics components, with a head size of 26 mm. We excluded cups with anteversion of over 20 degrees and measured linear wear by a new method using a digitiser and special software of our design. Follow-up was from two to five years (mean 4.3). The mean age at operation was 50.3 years, with more men than women (1.4:1). The mean linear wear per year was 0.15 mm; this did not increase with the longevity of the prosthesis (p = 0.54). In 59 hips showing evidence of osteolysis, the mean linear wear rate was significantly higher at 0.23 mm/year (p <0.001). The mean linear wear rate also correlated significantly with age at the time of operation (p = 0.008), but we found no significant correlations with body-weight, gender, aetiology of the disease, thickness of polyethylene, or cup position. Our new method of measurement is time-saving and reproducible. The results confirm the greater rate of linear wear of polyethylene in patients showing osteolysis and in those who are younger.

Identification and purification of a spinach chloroplast DNA-binding protein that interacts specifically with the plastid psaA-psaB-rps14 promoter region

We have previously shown the presence in chloroplasts of sequence-specific DNA-binding proteins that interact specifically with two regions located downstream and upstream from the 5'-transcription start site of the plastid psaA-psaB-rps14 operon. As part of an effort to elucidate the regulatory mechanism of plastid transcription during plant development, we report here the purification and characterization of the chloroplast DNA-binding protein from spinach (Spinacia oleracea L. var. spinosa Ashers et Graeden) leaves that specifically recognizes sequences between positions +64 to +83 relative to the transcription start site. This DNA-binding protein has been highly purified from chloroplasts by using a combination of high-salt extraction, ammonium sulfate precipitation, heparin-agarose chromatography, and sequence-specific DNA-affinity chromatography. The protein exhibited an apparent molecular weight of 59-60 kDa on the basis of gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by Southwestern blot analysis further indicated that this DNA-binding protein is dimeric and composed of two approximately 31-kDa subunits. We discuss the properties of this protein in relation to the known chloroplast DNA-binding factors for plastid gene expression.

Introduction and expression of foreign DNA in isolated spinach chloroplasts by electroporation

An electroporation-mediated method for the study of foreign gene expression within chloroplasts has been developed. The chloroplast expression vector pHD203-GUS, which consists of coding regions for beta-glucuronidase (GUS) and chloramphenicol acetyltransferase (CAT) separated by a double psbA promoter fragment from pea (in opposite orientation) was electroporated into spinach chloroplasts and the transient gene expression was examined. Conditions for the expression of the reporter genes have been optimized. Both CAT and GUS activities were detected in chloroplasts electroporated with pHD203-GUS, but not with nuclear expression vector pBI221 or negative control pUC18. No GUS activity was detected when pHD203-GUS was electroporated into spinach protoplasts. Dot immunoblot analysis using anti-GUS antibody confirmed the existence of GUS protein in chloroplasts electroporated with chloroplast-specific vector but not the negative controls, excluding the possibilities of endogenous GUS or bacterial contamination. The expression of GUS protein in treated chloroplasts was further confirmed by Western blot analysis.

Characterization of the light-responsive promoter of rice chloroplast psbD-C operon and the sequence-specific DNA binding factor

The transcription of rice plastid psbD-psbC genes encoding photosystem II reaction center protein D2 and chlorophyll alpha-binding protein CP43 is closely regulated by light. To elucidate the sequence requirement for the light-responsive promoter of psbD-psbC operon, transcriptional analysis of the rice promoter was performed with deleted mutants and site-directed mutants in vitro. Deletion of -546 approximately -100 upstream sequences resulted in 4- to 5-fold decrease in the transcription rate. Further deletion of -99 approximately -40 conserved region of repeated sequences resulted in 2-fold decrease in the transcription rate. The core light-responsive promoter requires "-10" element but not "-35" element for accurate initiation of basal transcription. No downstream promoter element was found in the +4 approximately +111 region. The competitive gel-retardation experiments revealed the presence of DNA-binding protein in the rice chloroplasts, which interacts specifically with the -60 approximately -37 repeated sequences. Southwestern blot analysis further demonstrated that the binding factor is composed of 36-kDa polypeptide(s).

[Myocardial perfusion studies during exertion and rest performed at the Hospital Militar Gorgas (HMG)]

We report the experience at Gorgas Army Hospital with myocardial perfusion studies by single-photon emission tomography. We describe the technique, the specificity and sensitivity, and its use in the diagnosis, evaluation of extension and prognosis of coronary artery disease.

The effect of cell density on the production of xylitol from D-xylose by yeast

The rate of xylitol production from D-xylose increased with increasing yeast cell density. The optimal temperature for xylitol production is 36 degrees C, and the optimal pH range is from 4.0 to 6.0. At high initial yeast cell concentration of 26 mg/mL, 210 g/L of xylitol was produced from 260 g/L of D-xylose after 96 h of incubation with an indicated yield of 81% of the theoretical value.

A method of dynamic analysis of iodine-123-metaiodobenzylguanidine scintigrams in cardiac mechanical overload hypertrophy and failure

Cardiac sympathetic neuronal degeneration accompanies mechanical overload heart failure. We hypothesized that sympathetic nerve and myocyte failure share a common etiology and that 123I-metaiodobenzylguanidine (MIBG) might provide a precise method of detecting failure in chronic mechanical overload. Our aim was to develop a method for the dynamic analysis of 123I-MIBG scintigrams which could yield a quantitative index of myocardial sympathetic neuronal function in this condition. We performed serial 123I-MIBG scintigraphy in 33 volunteers, 10 orthotopic cardiac transplant recipients and 26 patients with chronic mechanical overload of the left ventricle. We constructed a compartmental model in which total heart activity represents the sum of cardiac sympathetic vesicular and cytosolic pools. Patients with antecedent mechanical overload heart failure or myocardial dysfunction had accelerated myocardial egress of tracer that we ascribed to a specific impairment in vesicular storage rather than to a more rapid turnover of an intact vesicular pool.

An improved method for disruption of microbial cells with pressurized carbon dioxide

Disruption of microbial cells by pressurized carbon dioxide at both subcritical and supercritical temperatures has been previously investigated. This method differs in principle from other disruption techniques and was found to have potential applications for rupture of a variety of microorganisms. However, it is not as effective for some of the microbial cells, including yeast, of which the cell walls are extremely robust and rigid. This work suggests an alternative operation to improve the disruption rates of cells by repeatedly releasing the applied fluid pressure within the cells in the midst of a disruption process. The improvement is substantial at all the experimental conditions studied.

Porous-coated acetabular component. Quantitative assessment of normal radiophosphate uptake as a function of implant age

A computer-assisted quantitative analysis was undertaken of normal radiophosphate bone uptake adjacent to the porous-coated acetabular component in asymptomatic patients. Implants ranged from 1.6 to 49 months of age. In 62 hips, it was found that implants newer than 12 months of age had uptakes that were significantly greater than those 12 months or older. Between 12 and 49 months, there was no correlation with age, indicating a stabilization of the remodeling process.