Prenatal diagnosis of oculocutaneous albinism two mutations located at the same allele

A pregnant woman accepted amniocentesis on account of the previous birth of type 1 oculocutaneous albinism (OCA1). PCR revealed that the fetus had two mutations (862delTT, Arg 299His). The father had one missense mutation (Arg 299Ser) and the mother had the same mutations as the fetus. Two mutations of the fetus located at the same allele were suspected. Postpartal follow-up confirmed his carrier status. For recessive disorders, faced with a fetus with two mutations, the importance of performing segregation analysis of mutation on both parents is emphasized. This could exclude two mutations located at the same allele and prevent the unnecessary termination of a fetus with carrier status.

Sequences at the 3' untranslated region of bamboo mosaic potexvirus RNA interact with the viral RNA-dependent RNA polymerase

The 3' untranslated region (UTR) of bamboo mosaic potexvirus (BaMV) genomic RNA was found to fold into a series of stem-loop structures including a pseudoknot structure. These structures were demonstrated to be important for viral RNA replication and were believed to be recognized by the replicase (C.-P. Cheng and C.-H. Tsai, J. Mol. Biol. 288:555-565, 1999). Electrophoretic mobility shift and competition assays have now been used to demonstrate that the Escherichia coli-expressed RNA-dependent RNA polymerase domain (Delta 893) derived from BaMV open reading frame 1 could specifically bind to the 3' UTR of BaMV RNA. No competition was observed when bovine liver tRNAs or poly(I)(C) double-stranded homopolymers were used as competitors, and the cucumber mosaic virus 3' UTR was a less efficient competitor. Competition analysis with different regions of the BaMV 3' UTR showed that Delta 893 binds to at least two independent RNA binding sites, stem-loop D and the poly(A) tail. Footprinting analysis revealed that Delta 893 could protect the sequences at loop D containing the potexviral conserved hexamer motif and part of the stem of domain D from chemical cleavage.

Molecular analysis of Wilson disease in Taiwan: identification of one novel mutation and evidence of haplotype-mutation association

Wilson disease (WND) is caused by a deficiency of the copper-transporting enzyme, P-type ATPase (ATP7B). Twelve different mutations have previously been identified in Taiwan Chinese with Wilson disease. We, herein, report another 4 missense mutations, 1 of which is novel. We did haplotype analysis of Taiwanese WND chromosomes, using three well characterized short tandem repeat markers (haplotype was assigned in the order of D13S314-D13S301-D13S316). Association correlation was found between the mutations and their respective haplotypes. Haplotype-deduced pedigree analysis was shown to be helpful in the mutation analysis of WND chromosomes and in the molecular assessment of both pre-symptomatic WND patients and carriers. Given the complexity and heterogeneity of the mutation spectrum of ATP7B, we suggest that haplotype analysis should be performed before full-scale mutation analysis.

Longitudinal survey of blood flow at three different locations in the middle cerebral artery in normal fetuses

OBJECTIVES

To assess vascular impedance at three different locations in the middle cerebral artery (MCA) in normal fetuses throughout gestation.

MATERIALS AND METHODS

Uncomplicated singleton pregnancies at 15-40 weeks' gestation in which Doppler surveys of both MCAs could be obtained were recruited. The pulsatility index (PI) and resistance index (RI) of the proximal, mid and distal sites of both MCAs were measured. The five gestation periods at which the Doppler surveys were performed were (i) 15-19 completed weeks; (ii) 20-24 completed weeks; (iii) 25-29 completed weeks; (iv) 30-34 completed weeks; (v) 35-39 completed weeks.

RESULTS

A total of 42 fetuses were recruited. The average PI/RI values of the proximal, mid and distal MCA were 1.61/0.82, 1.77/0.82, and 1.84/0.84, respectively. The PI value of the proximal MCA was lower than that of the mid and distal MCA. The PI values of the mid and distal MCA showed no difference. The RI value of the MCA from the three locations also showed no difference. The PI/RI values of MCA for each gestational phase were: (i) 1.81/0.87; (ii) 1.79/0.86; (iii) 1.78/0.86; (iv) 1.70/0.81; (v) 1.62/0.77, respectively. Decreased PI/RI values were observed after 30 weeks' gestation.

CONCLUSIONS

The PI values of the proximal MCA are lower than those of the mid and distal MCA. A marked decrease in PI/RI values was observed after 30 weeks' gestation.

Reversal caused by n-butylidenephthalide from the deficits of inhibitory avoidance performance in rats

The present study was designed to investigate the mechanism of action of n-butylidenephthalide on the deficits of inhibitory avoidance performance induced by drugs in rats with piracetam as a positive control. n-Butylidenephthalide attenuated the scopolamine-induced and mecamylamine-induced acquisition impairment, and also attenuated the acquisition impairment induced by scopolamine plus mecamylamine. Furthermore, scopolamine methylbromide, a peripheral cholinergic muscarinic receptor antagonist, did not block the counteracting effect of n-butylidenephthalide on the scopolamine-induced acquisition impairment. n-Butylidenephthalide attenuated the impairment of inhibitory avoidance performance induced by the central acetylcholinergic neurotoxin AF64A administered intracisternally. From the above results, we suggest that n-butylidenephthalide attenuated the deficits of inhibitory avoidance performance induced by drugs, which are the effects related to activating the central but not the peripheral cholinergic neuronal system via muscarinic and nicotinic receptors.

Rapid monitoring assay of congenital adrenal hyperplasia with microbore high-performance liquid chromatography/electrospray ionization tandem mass spectrometry from dried blood spots

17-hydroxyprogesterone (17OHP) is the most important plasma parameter for diagnosing and monitoring congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency. A rapid, simple, and specific method based on microbore high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (micro-HPLC/ESI-MS/MS) was developed to determine the presence of 17OHP on dried filter-paper blood samples from patients with CAH caused by 21-hydroxylase deficiency. 17OHP from dried blood spots formed by the action of Girard reagent P (GirP) turned out to be a water-soluble hydrazone complex. Derivatization with GirP led to higher ESI sensitivity for 17OHP. The LC/MS/MS detection of GirP-derivatized 17OHP (GirP-17OHP) was rapid (<3 min). The method is repeatable and reproducible, with CVs <7% and 12%, respectively. This new method was used for direct determination of 17OHP in dried blood specimens obtained from abnormal children and infants of various ages with a detection limit of 10 ng/mL ( approximately 12 microL blood). The method described allows for rapid and reliable measurements of 17OHP in dried blood specimens from patients affected by CAH.

Distension of urinary bladder induces exaggerated coronary constriction in smokers with early atherosclerosis

Distension of the urinary bladder causes an increase in efferent sympathetic activity, which can precipitate myocardial ischemia. Smoking has been shown to modulate activities of afferent nerves from the distended urinary bladder and to impair endothelial function in response to sympathetic activation. To assess the effect of bladder distension on coronary dynamics in smokers, we measured epicardial and microvascular responses in 24 patients with early atherosclerosis (< 50% diameter stenosis). Patients were classified into habitual smokers (group 1, n = 14) and nonsmokers (group 2, n = 10). Habitual smokers were randomized into two subgroups on the basis of the use of doxazosin, as follows: subgroup 1A (n = 7), without administration of doxazosin before catheterization; subgroup 1B (n = 7), with dosing doxazosin. In response to bladder distension (mean intravesical pressure 21.5 mmHg), bladder distension significantly decreased coronary diameter at the stenotic segments, coronary blood flow, and increased coronary resistance compared with baseline values, in subgroup 1A patients. In subgroup 1B patients during bladder distension, coronary diameter, coronary blood flow, and coronary resistance did not show significant changes compared with baseline values. There were significant differences of coronary diameter at the stenotic segments, coronary blood flow, and of changes of coronary vascular resistance between subgroup 1A and group 2 during bladder distension, despite similar changes in rate-pressure product. The present study showed that urinary bladder distension caused an abnormal vasomotor response of epicardial vasoconstriction and a concomitant increased coronary resistance, which leads to reduction in coronary blood flow in patients with early atherosclerosis. Smoking may further impair the response, implying that smoking has exaggerated response to sympathetic stimulation of conduit and resistance vessels. The abnormal response was abolished by pretreated administration of doxazosin, suggesting that the involved mechanisms are related to alpha(1)-adrenoceptors.

Genetic risk factors of sporadic Alzheimer's disease among Chinese in Taiwan

To evaluate the genetic factors for AD among a Chinese population in Taiwan, we studied the polymorphisms of six candidate genes of Alzheimer's disease (AD), including the regulatory region of apolipoprotein E (Apo-E, G-186T), the promoter of apolipoprotein E (Apo-E, A-491T), the bleomycin hydrolase gene (BH, A1450G), a mutation of alpha(2)-macroglobulin gene (A2M G2998A), low-density lipoprotein receptor-related protein gene (LRP, C766T), and alpha(1)-antichymotrypsin gene (ACT, -15Ala/Thr) in AD patients and non-affected elder individuals among Taiwanese Chinese. Eighty-two AD patients and 110 non-affected individuals were recruited for this study. We used polymerase chain reaction (PCR) and restriction enzyme digestion to identify their genotypes. The statistical examination was performed by combining the results of our previous reports - apolipoprotein E epsilon4 (ApoE-4), presenilin-1 intronic polymorphism (PS-1, allele 1/2), and the five-nucleotide deletion of alpha(2)-macroglobulin gene (A2M). Among these nine candidate genes of AD, the ApoE-4 allele is the only independent genetic risk factor for AD. The other candidate genes in this study were not associated with the occurrence of AD. In addition, there are no gene-gene interactions.

An additional H-bond in the alpha 1 beta 2 interface as the structural basis for the low oxygen affinity and high cooperativity of a novel recombinant hemoglobin (beta L105W)

Site-directed mutagenesis has been used to construct three recombinant mutant hemoglobins (rHbs), rHb(beta L105W), rHb(alpha D94A/betaL105W), and rHb(alpha D94A). rHb(beta L105W) is designed to form a new hydrogen bond from beta 105Trp to alpha 94Asp in the alpha(1)beta(2) subunit interface to lower the oxygen binding affinity by stabilizing the deoxy quaternary structure. We have found that rHb(beta L105W) does indeed possess a very low oxygen affinity and maintains normal cooperativity (P(50) = 28.2 mmHg, n(max) = 2.6 in 0.1 M sodium phosphate at pH 7.4) compared to those of Hb A (P(50) = 9.9 mmHg, n(max) = 3.2 at pH 7.4). rHb(alpha D94A/beta L105W) and rHb(alpha D94A) are expressed to provide evidence that rHb(betaL 105W) does form a new H-bond from beta 105Trp to alpha 94Asp in the alpha(1)beta(2) subunit interface of the deoxy quaternary structure. Our multinuclear, multidimensional nuclear magnetic resonance (NMR) studies on (15)N-labeled rHb(beta L105W) have identified the indole nitrogen-attached (1)H resonance of beta 105Trp for rHb(beta L105W). (1)H NMR studies on Hb A and mutant rHbs have been used to investigate the structural basis for the low O(2) affinity of rHb(beta L105W). Our NMR results provide evidence that rHb(beta L105W) forms a new H-bond from beta 105Trp to alpha 94Asp in the alpha(1)beta(2) subunit interface of the deoxy quaternary structure. The NMR results also show that these three rHbs can switch from the R quaternary structure to the T quaternary structure in their ligated state upon addition of an allosteric effector, inositol hexaphosphate. We propose that the low O(2) affinity of rHb(beta L105W) is due to the formation of a new H-bond between alpha 105Trp and alpha 94Asp in the deoxy quaternary structure.

Novel recombinant hemoglobin, rHb (beta N108Q), with low oxygen affinity, high cooperativity, and stability against autoxidation

Using our Escherichia coli expression system, we have constructed rHb (beta N108Q), a new recombinant hemoglobin (rHb), with the amino acid substitution located in the alpha(1)beta(1) subunit interface and in the central cavity of the Hb molecule. rHb (beta N108Q) exhibits low oxygen affinity, high cooperativity, enhanced Bohr effect, and slower rate of autoxidation of the heme iron atoms from the Fe(2+) to the Fe(3+) state than other low-oxygen-affinity rHbs developed in our laboratory, e.g., rHb (alpha V96W) and rHb (alpha V96W, beta N108K). It has been reported by Olson and co-workers [Carver et al. (1992) J. Biol. Chem. 267, 14443-14450; Brantley et al. (1993) J. Biol. Chem. 268, 6995-7010] that the substitution of phenylalanine for leucine at position 29 of myoglobin can inhibit autoxidation in myoglobin and at position 29 of the alpha-chain of hemoglobin can lower NO reaction in both the deoxy and the oxy forms of human normal adult hemoglobin. Hence, we have further introduced this mutation, alpha L29F, into beta N108Q. rHb (alpha L29F, beta N108Q) is stabilized against auto- and NO-induced oxidation as compared to rHb (beta N108Q), but exhibits lower oxygen affinity at pH below 7.4 and good cooperativity as compared to Hb A. Proton nuclear magnetic resonance (NMR) studies show that rHb (beta N108Q) has similar tertiary structure around the heme pockets and quaternary structure in the alpha(1)beta(1) and alpha(1)beta(2) subunit interfaces as compared to those of Hb A. The tertiary structure of rHb (alpha L29F, beta N108Q) as measured by (1)H NMR, especially the alpha-chain heme pocket region (both proximal and distal histidyl residues), is different from that of CO- and deoxy-Hb A, due to the amino acid substitution at alpha L29F. (1)H NMR studies also demonstrate that rHb (beta N108Q) can switch from the R quaternary structure to the T quaternary structure without changing ligation state upon adding an allosteric effector, inositol hexaphosphate, and reducing the temperature. On the basis of its low oxygen affinity, high cooperativity, and stability against autoxidation, rHb (beta N108Q) is considered a potential candidate for the Hb-based oxygen carrier in a blood substitute system.

Bacterial infection in patients with transfusion-dependent beta-thalassemia in central Taiwan

The microorganisms, outcome of infections and the risk factors were evaluated in 39 patients with beta-thalassemia who received frequent blood transfusions. Among these patients, thirteen developed 22 episodes of infections, and bacteremia accounted for 72.7% (16/22) of all infections. Three patients developed meningitis, two patients had liver abscesses, three patients had soft tissue infections, one patient had a urinary tract infection and one patient had lobar pneumonia. Interestingly, a large proportion of the patients were infected by Gram-negative bacteria. Patients who were implanted with intravascular catheters were most susceptible to bacterial infection (1.70 episodes/patient) (P = 0.0069). So were patients with ferritin levels over 2,000 ng/mL (1.18 episodes/patient) (P = 0.028). The frequency of bacterial infections in patients with splenectomies (1.08 episode/patient) was also significantly higher than that of the average patient (P = 0.025). In conclusion, three major risk factors for bacterial infection were identified in this group of patients: intravascular catheterization, high serum ferritin levels (> or = 2,000 ng/mL) and splenectomy. The infection rate of these patients (0.45 episode/100 patient-year) is about 20-fold higher than that of general pediatric patients (0.023 episode/100 patient-year).

Lewis (FUT3) genotypes in Taiwanese, Thai, and Filipino populations

The Lewis (Le) blood type comprises two major antigens, Le(a) and Le(b), which are encoded by alpha (1,2)-fucosyltransferase (FUT2) and a (1,3/1,4)-fucosyl-transferase (FUT3). In this study, we analyzed the mutations of FUT3 in Taiwanese, Thai, and Filipino populations and correlated these with serologic phenotypes. One hundred and thirty-seven Taiwanese, 71 Thai, and 125 Filipino were studied unselectively. The frequency of the normal and four other mutant alleles for Taiwanese, Thai, and Filipino, respectively, were as follows: 187/274 (68.2%), 87/142 (61.3%), and 160/250 (64.0%) were wild type (Le); 14/274 (5.1%), 1/142 (0.7%), and 1/250 (0.4%) were a T202C/C314T mutation (le202,314); 35/274 (12.8%), 15/142 (10.6%), and 22/250 (8.8%) had the G508A mutation (le508); and 38/274 (13.9%), 39/142 (27.4%), and 67/250 (26.8%) carried the T1067A mutation (le1067). The le445 and le1007 were not detected in this study. Our result provided the first genetic data of the FUT3 gene in these three populations, and the frequency distribution of mutant alleles among Taiwanese, Thai, and Filipinos demonstrates a significant difference (P<0.001). In our study, the le202,314 mutation had considerable frequency in the Taiwanese, but the le1067 mutation had a higher frequency in Thai and Filipinos.

Breech deformation complex in neonates

OBJECTIVE

To demonstrate the association of minor anomalies and breech-presenting newborns with breech deformation complex.

STUDY DESIGN

A total of 3,345 newborns with singleton, term delivery were examined based on a list of 67 items of major and minor anomalies. All infants were divided into two groups: group 1, vertex presentation (3,107 infants); group 2, breech presentation (224 infants). The prevalence of anomalies between both groups was compared.

RESULTS

There were 1,495 (44.9%) infants with one or more minor anomalies, which included 1,313 infants (42.3%) in group 1 and 182 (81.3%) in group 2 (P < .005). The prevalence of anomalies in groups 1 and 2 were: frontal bossing (1.8% vs. 51%), prominent occiput (0.8% vs. 42%), upward slant (11.6% vs. 23.7%) and low-set ears (0.3% vs. 20.5%). Torticollis (0.3% vs. 1.78%) and congenital dislocation of the hip (CDH) (0.06% vs. 0.9%) (all P < .005) were related to breech presentation.

CONCLUSION

Breech-presenting newborns had a higher risk of combining breech deformation complex, torticollis and CDH. The criteria for breech deformation complex included frontal bossing, prominent occiput, upward slant and low-set ears. The prevalence of breech deformation complex, torticollis and CDH was not related to the delivery method.

Cryogen free automated gas chromatography for the measurement of ambient volatile organic compounds

An automated gas chromatographic system was constructed for measuring ambient volatile organic compounds (VOCs). Preconcentration of the VOCs was performed by using two separated sorbent traps of different combinations with each designated for either low or high boiling VOCs. Both traps and their associated valve systems were integrated as a complete system sharing a common sample inlet. Precise temperature controls for desorption relied on the use of a process controller with proportional-integral-derivative algorithm to throttle the current supply. No additional cryo-focusing stage prior to the column was needed owing to the flash heating capability for desorption. Other than the cryogen free preconcentration and focusing, the separation of VOCs of large volatility difference was also performed without cryogen. The system employed an Al2O3/KCl porous-layer open tubular column for separating C3-C7 compounds; and a DB-1 column for C6-C12. This automated GC system has been deployed in a Taiwan Environmental Protection Agency urban air quality monitoring station of Taiwan for continuous measuring C3-C7 ozone precursors. Excellent correlation between the car exhaust type of compounds measured by our GC system and carbon monoxide measured by a non-dispersive infrared spectrometer was observed, suggesting the automated GC system was robust and reliable.

Outbreak investigation of nosocomial enterobacter cloacae bacteraemia in a neonatal intensive care unit

Over a period of 7 months, 23 patients hospitalized in a neonatal intensive care unit (NICU) developed nosocomial Enterobacter cloacae bacteraemia. Contaminated saline for preparing heparin solution was initially identified as the common source of E. cloacae bacteraemia. Although environmental sanitation was enforced, the outbreak continued. E. cloacae has always been isolated from various cultures of the environmental specimens, from the hands of personnel and from the faeces of patients. All of the 23 bacteraemic isolates and 8 stool isolates from infected infants, as well as the 17 isolates from environmental specimens were found to be of the same genotype using the polymerase chain reaction-based DNA fingerprinting method. After various infection control methods were instituted, the outbreak eventually came under control. For epidemiological investigation, 23 neonates without E. cloacae bacteraemia were matched for case-control study. Nineteen (83%) of the case-patients were premature. The significant risk factors leading to E. cloacae bacteraemia in the NICU included small gestation age, low birthweight, exposure to personnel with contaminated hands and the presence of E. cloacae in the stool carriage (p=0.003, 0.007, 0.018 and 0.040, respectively). The gastrointestinal tracts of the patients and environmental surfaces appeared to be the principal sites of bacterial reservoir. In conclusion, the outbreak of E. cloacae bacteraemia was caused by a particular strain and possibly via multiple modes of transmission, including a bottle of contaminated saline as an initial common source, endogenous spread from the gastrointestinal tract and successive cross-infections between patients, hands of personnel and the environment. Effective infection control requires a multidisciplinary approach and reinforcement of infection control procedures, including aseptic technique, hand washing, proper isolation and disinfection of environmental surfaces.

Polymorphisms of the parkin gene in sporadic Parkinson's disease among Chinese in Taiwan

The role of genetics in Parkinson's disease (PD), previously controversial, is now documented by several studies. A major breakthrough has been the discovery of two single-gene defects in familial PD. A single base pair change at position 209 from G to A (G209A) in the fourth exon of the alpha-synuclein gene has been identified in cases of autosomal dominant familial PD. Mutations in the Parkin gene can induce autosomal recessive juvenile parkinsonism. A polymorphism of R/W366 in the Parkin gene was found to be associated with a protective factor for sporadic PD. We surveyed the polymorphisms of the Parkin gene, including S/N167, R/W366 and V/L380, in 92 cases of sporadic PD and 98 nonaffected individuals in Taiwanese Chinese. The allele frequencies of these polymorphisms are not significantly different between PD and nonaffected controls. We conclude that polymorphisms of the Parkin gene, S/N167, R/W366, V/L380, are not genetic factors for sporadic PD among Chinese in Taiwan.

Age-related alteration of gap junction distribution and connexin expression in rat aortic endothelium

We investigated endothelial gap junctions and their three component connexins, connexin37 (Cx37), Cx40, and Cx43, during growth and senescence in rat aorta by en face immunoconfocal microscopy and electron microscopy. Gap junction spots labeled by specific antisera against Cx37, Cx40, and Cx43 were quantified at 1 day, 7 days, 28 days, 16 months, and > or =20 months of age, and the relationship between the connexins was examined by co-localization analysis. At birth, all three connexins were abundantly expressed; the number and total area of connexin spots then declined within 1 week (p<0.05 for each connexin). From 1 week, each connexin showed a distinct temporal expression pattern. Whereas Cx43 signal decreased progressively, Cx37 signal fluctuated in a downward trend. By contrast, Cx40 maintained an abundant level until > or =20 months of age (> or =20 months vs. 28 days, p<0.05 for number and total connexin signal area). These patterns were associated with changes in endothelial cell morphology. Double-label analysis showed that the extent of co-localization of connexins to the same gap junctional spot was age-dependent [>70% at birth and 28 days old; <70% at later stages (p<0.05)]. We conclude that expression of the three connexins in aortic endothelium is age-related, implying specific intercellular communication requirements during different stages after birth.

Identification and characterization of a structural protein of hepatitis B virus: a polymerase and surface fusion protein encoded by a spliced RNA

The hepatitis B virus (HBV) genome is known to contain four conserved and overlapped open reading frames (ORFs) encoding the viral core, polymerase (P), surface (S), and X proteins. Whether HBV encodes other proteins has long been a major interest in the field. Using (32)P-labeling of an introduced protein kinase A site attached to the N- or C-terminus of the HBV polymerase gene, a 43-kDa P-S fusion protein was detected in cell lysate, secreted virions, and 22-nm subviral particles. Immunobiochemical studies showed that the 43-kDa protein contains the epitopes of the N-terminus of polymerase and most parts of the surface proteins. This 43-kDa protein was shown to be a glycoprotein, similar to the surface protein. RT-PCR and sequence analyses identified a spliced mRNA which was derived from pregenomic RNA with a deletion of 454 nucleotides (nt) from nt 2447 to 2902. This splice event creates a P-S fusion ORF. This finding is consistent with the result obtained from an immunobiochemical study. Mutations at the splice donor or acceptor site on the HBV genome abrogated the production of the 43-kDa protein. These mutants had no effect on viral replication in transfected HuH-7 cells. However, this P-S fusion protein is able to substitute for the LS protein in virion maturation. On the basis of these results, we conclude that the 43-kDa protein is a polymerase-surface fusion protein encoded by a spliced RNA. Similar to the LS protein, the 43-kDa P-S fusion protein is a structural protein of HBV and might play a role in the HBV life cycle.