Serotonin Content of the Lungs, Brains, and Blood of Mice Exposed to 0.45 ppm Nitrogen Dioxide

Young adult male Swiss Webster mice were exposed to 0.45 ppm of nitrogen dioxide (NO2) for 7 hours per day for 4 weeks. The lungs and brains were assayed for serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) content by high-performance liquid chromatography. Lung 5-HT content for the exposed animals was 13.1% less than that for the control group, but this difference was not statistically significant. Brain 5-HT and 5-HIAA were significantly elevated, +17.3% (P < 0.005) and +47.3% (P 0.001), respectively, and the ratios of 5-HIAA to 5-HT were also higher (P 0.005). The results suggest that further exploration of lung and brain serotonin alterations by air pollutants may offer useful discriminates for the evaluation of air quality.

Effects of increased image noise on image quality and quantitative interpretation in brain CT perfusion

BACKGROUND AND PURPOSE

There is a desire within many institutions to reduce the radiation dose in CTP examinations. The purpose of this study was to simulate dose reduction through the addition of noise in brain CT perfusion examinations and to determine the subsequent effects on quality and quantitative interpretation.

MATERIALS AND METHODS

A total of 22 consecutive reference CTP scans were identified from an institutional review board-approved prospective clinical trial, all performed at 80 keV and 190 mAs. Lower-dose scans at 188, 177, 167, 127, and 44 mAs were generated through the addition of spatially correlated noise to the reference scans. A standard software package was used to generate CBF, CBV, and MTT maps. Six blinded radiologists determined quality scores of simulated scans on a Likert scale. Quantitative differences were calculated.

RESULTS

For qualitative analysis, the correlation coefficients for CBF (-0.34; P < .0001), CBV (-0.35; P < .0001), and MTT (-0.44; P < .0001) were statistically significant. Interobserver agreements in quality for the simulated 188-, 177-, 167-, 127-, and 44-mAs scans for CBF were 0.95, 0.98, 0.98, 0.95, and 0.52, respectively. Interobserver agreements in quality for the simulated CBV were 1, 1, 1, 1, and 0.83, respectively. For MTT, the interobserver agreements were 0.83, 0.86, 0.88, 0.74, and 0.05, respectively. For quantitative analysis, only the lowest simulated dose of 44 mAs showed statistically significant differences from the reference scan values for CBF (-1.8; P = .04), CBV (0.07; P < .0001), and MTT (0.46; P < .0001).

CONCLUSIONS

From a reference CTP study performed at 80 keV and 190 mAs, this simulation study demonstrates the potential of a 33% reduction in tube current and dose while maintaining image quality and quantitative interpretations. This work can be used to inform future studies by using true, nonsimulated scans.

Mutations in monoamine oxidase (MAO) genes in mice lead to hypersensitivity to serotonin-enhancing drugs: implications for drug side effects in humans

A possible side effect of serotonin-enhancing drugs is the serotonin syndrome, which can be lethal. Here we examined possible hypersensitivity to two such drugs, the serotonin precursor 5-hydroxy-L-tryptophan (5-HTP) and the atypical opioid tramadol, in mice lacking the genes for both monoamine oxidase A (MAOA) and MAOB. MAOA/B-knockout (KO) mice displayed baseline serotonin syndrome behaviors, and these behavioral responses were highly exaggerated following 5-HTP or tramadol versus baseline and wild-type (WT) littermates. Compared with MAOA/B-WT mice, baseline tissue serotonin levels were increased ∼2.6-3.9-fold in MAOA/B-KO mice. Following 5-HTP, serotonin levels were further increased ∼4.5-6.2-fold in MAOA/B-KO mice. These exaggerated responses are in line with the exaggerated responses following serotonin-enhancing drugs that we previously observed in mice lacking the serotonin transporter (SERT). These findings provide a second genetic mouse model suggestive of possible human vulnerability to the serotonin syndrome in individuals with lesser-expressing MAO or SERT polymorphisms that confer serotonergic system changes.

Isolation, identification, and characterization of a feather-degrading bacterium

A feather-degrading culture was enriched with isolates from a poultry waste digestor and adapted to grow with feathers as its primary source of carbon, sulfur, and energy. Subsequently, a feather-hydrolytic, endospore-forming, motile, rod-shaped bacterium was isolated from the feather-degrading culture. The organism was Gram stain variable and catalase positive and demonstrated facultative growth at thermophilic temperatures. The optimum rate of growth in nutrient broth occurred at 45 to 50 degrees C and at pH 7.5. Electron microscopy of the isolate showed internal crystals. The microorganism was identified as Bacillus licheniformis PWD-1. Growth on hammer-milled-feather medium of various substrate concentrations was determined by plate colony count. Maximum growth (approximately 10 cells per ml) at 50 degrees C occurred 5 days postinoculation on 1% feather substrate. Feather hydrolysis was evidenced as free amino acids produced in the medium. The most efficient conditions for feather fermentation occurred during the incubation of 1 part feathers to 2 parts B. licheniformis PWD-1 culture (10 cells per ml) for 6 days at 50 degrees C. These data indicate a potential biotechnique for degradation and utilization of feather keratin.

Purification and Characterization of a Keratinase from a Feather-Degrading Bacillus licheniformis Strain

A keratinase was isolated from the culture medium of feather-degrading Bacillus licheniformis PWD-1 by use of an assay of the hydrolysis of azokeratin. Membrane ultrafiltration and carboxymethyl cellulose ion-exchange and Sephadex G-75 gel chromatographies were used to purify the enzyme. The specific activity of the purified keratinase relative to that in the original medium was approximately 70-fold. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis and Sephadex G-75 chromatography indicated that the purified keratinase is monomeric and has a molecular mass of 33 kDa. The optimum pH and the pI were determined to be 7.5 and 7.25, respectively. Under standard assay conditions, the apparent temperature optimum was 50 degrees C. The enzyme is stable when stored at -20 degrees C. The purified keratinase hydrolyzes a broad range of substrates and displays higher proteolytic activity than most proteases. In practical applications, keratinase is a useful enzyme for promoting the hydrolysis of feather keratin and improving the digestibility of feather meal.

Genetic evaluation and management of fetal chylothorax: review and insights from a case of Noonan syndrome

Fetal chylothorax is one of a very few syndromes that can be treated in utero with thoracoamniotic shunting or pleurodesis by OK-432 as two major therapeutic modalities. We report on a fetus with Noonan syndrome and a missense mutation c.182A > C (p.Asp61Ala) of PTPN11 who responded poorly to antenatal pleurodesis by OK-432. Based on our previous publication and this case study, we propose that fetal chylothorax of a distinct genetic origin may respond poorly to OK-432 pleurodesis.

Role of three-dimensional power Doppler in the antenatal diagnosis of placenta accreta: comparison with gray-scale and color Doppler techniques

OBJECTIVE

To assess the role of three-dimensional (3D) power Doppler in the antenatal diagnosis of placenta accreta and compare its diagnostic performance with gray-scale and color Doppler ultrasonography.

METHODS

One hundred and seventy pregnant women with persistent placenta previa totalis (after 28 weeks' gestation) were prospectively enrolled into this study. Gray-scale transabdominal ultrasound examination was performed to detect loss of the subendometrial echolucent zone and other abnormalities suggestive of placenta accreta. Color flow mapping was used to scan the whole placenta to detect any newly formed vessels at the serosa-bladder border or the presence of abnormal lacunae. Finally a targeted examination of angioarchitecture in the basal and lateral views of the placenta was carried out using 3D power Doppler. The ultrasound findings were analyzed with reference to the final diagnosis made during Cesarean delivery.

RESULTS

Placenta accreta and its variants (including increta and percreta) were confirmed in 39 patients at the time of Cesarean delivery. Based on receiver-operating characteristics analysis, 'numerous coherent vessels' visualized using 3D power Doppler in the basal view was the best single criterion for the diagnosis of placenta accreta, with a sensitivity of 97% and a specificity of 92%. If we considered the presence of at least one criterion to be diagnostic when using each ultrasound technique, then 3D power Doppler would have the best positive predictive value (76%), followed by gray-scale (51%) and color Doppler (47%). The majority of patients with placenta accreta showed multiple characteristic features on ultrasound imaging. In contrast, those patients with a false-positive diagnosis (i.e. the final diagnosis was placenta previa alone) tended to show isolated ultrasound markers of the condition.

CONCLUSION

3D power Doppler may be useful as a complementary technique for the antenatal diagnosis or exclusion of placenta accreta.

'Big-eyed frog' sign on spatiotemporal image correlation (STIC) in the antenatal diagnosis of transposition of the great arteries

OBJECTIVE

To determine the value of simultaneous visualization of the cross-sectional view of both atrioventricular (AV) valves, the pulmonary artery and the aorta (en-face view of the AV valves and great vessels) in the identification of fetuses with transposition of the great arteries (TGA).

METHODS

This was a retrospective analysis of volume datasets obtained with the spatiotemporal image correlation (STIC) technique from 56 fetuses with and 30 fetuses without congenital heart defects. Volume datasets were reviewed offline to compare the en-face view of the AV valves and great vessels between fetuses with normal echocardiography and those with TGA.

RESULTS

The en-face view of both AV valves and great vessels in fetuses with TGA displayed the main pulmonary artery situated side-by-side with the aorta ('big-eyed frog' sign). In contrast, fetuses with normal hearts did not have this characteristic sonographic sign. This novel sonographic sign also helped to identify additional cases of TGA in 17 fetuses with complex heart defects.

CONCLUSION

The big-eyed frog sign may prove helpful in the prenatal diagnosis of TGA.

Stellate transformation of invasive trophoblast: a distinct phenotype of trophoblast that is involved in decidual vascular remodelling and controlled invasion during pregnancy

BACKGROUND

Successful implantation relies on the tightly regulated invasion of extravillous trophoblasts (EVTs). However, little is known about their phenotypic differentiation and relevant motile behaviour. Furthermore, the cell-cell interactions between EVTs and decidual arterioles during physiological transformation are also poorly understood.

METHODS

A total of 128 decidual specimens from early and late gestations containing components of EVTs and spiral arterioles were investigated using immunohistochemistry and periodic acid-Schiff reaction.

RESULTS

Unipolar, tadpole-like EVTs are observed throughout the interstitial area, with a tendency to decrease along the invasive pathway. The stellate differentiation of the EVTs is identified around and inside decidual arterioles or in the third-trimester myometrium. Furthermore, stellate transformation of EVTs precedes its interactions with the decidual arteriole. These specialized stellate trophoblasts invade and infiltrate the tunica media, accompanying lacuna formation inside the vessel wall and perturbation of actin fibre alignment of the tunica media.

CONCLUSION

Stellate transformation of trophoblasts may explain controlled invasion of EVTs and probably plays a key role in initiating cell-cell interaction in decidual vascular remodelling.

Prenatal three-dimensional ultrasound and magnetic resonance imaging evaluation of a fetal oral tumor in preparation for the ex-utero intrapartum treatment (EXIT) procedure

Recent attempts at predelivery management of obstructed fetal airways have focused on the EXIT (ex-utero intrapartum treatment) procedure, which allows sufficient time to secure the fetal airway through preservation of uteroplacental gas exchange. We report a fetus with an exophytic oral tumor noted at 34 weeks of gestation. In this case, three-dimensional (3D) ultrasound allowed a complete and interactive evaluation of the tumor and related facial anatomy, and confirmed that access to the fetal airway was unlikely during delivery. Fetal magnetic resonance imaging (MRI) further demonstrated that the tumor originated in the nasopharynx and obstructed the upper airway. Both imaging results led to a final decision to offer an EXIT procedure for the neonate. At 36 weeks' gestation, a successful EXIT procedure was performed to reduce the risk of respiratory distress immediately after birth. This report highlights the value of 3D ultrasound and MRI as essential prerequisites for optimization of the triage process in selecting EXIT candidates.

Regulation of MAO-A and MAO-B gene expression

MAO A and B genes are made of 15 exons with identical exon-intron organization. They are located on X-chromosome organized in opposite direction, tail to tail with 24 kb apart. Both promoters are GC-rich and regulated by transcription factor Sp1. However, they have distinctly different features. MAO B gene, but not MAO A gene, has TATA box. MAO B promoter contains two clusters of overlapping Sp1 sites, the CACCC repressor element. Transcription factors Sp1 and Sp4 can activate MAO B promoter activity through the proximal cluster of Sp1 sites and its activation can be repressed by the over-expression of Sp3 and a related family member, BTEB2. Decreased methylation and transcription repressor Sp3 upregulate human MAO B, but not MAO A, gene expression during Caco-2 differentiation. MAO B, but not MAO A gene, could be activated by PMA (phorbol 12-myristate 13-acetate) by protein kinase C, MAPkinase signal transduction pathway involves cJun and Egr-1. The differences in MAO A and B gene regulation may explain the different tissue-specific expression and functions of these two important isoenzymes.

Quantitative three-dimensional power Doppler ultrasound predicts the outcome of placental chorioangioma

The relationship of large and vascularized chorioangiomas to adverse pregnancy outcome is well recognized. We present a patient with a large placental tumor and signs of impending fetal cardiac failure. The angioarchitecture of the tumor depicted by three-dimensional (3D) power Doppler ultrasound enabled us to accurately diagnose a placental chorioangioma. During the follow-up period, quantitative flow data obtained using 3D power Doppler indicated altered hemodynamics in the tumor and concomitant improvement in the condition of the fetus, enabling us to manage the mother conservatively. Spontaneous delivery occurred at 38 weeks without any complications. This report demonstrates the potential value of 3D power Doppler in prenatal diagnosis and monitoring of pregnancies complicated by large, vascularized chorioangioma.

MAO-B knockout mice exhibit deficient habituation of locomotor activity but normal nicotine intake

Low levels of monoamine oxidase-B (MAO-B) activity, such as those observed in smokers, are also associated with behavioral traits such as a heightened responsiveness to novelty. However, the exact mechanism by which low MAO-B activity influences smoking and heightened responsiveness to novelty is still poorly understood. We used MAO-B knockout (KO) mice to test the hypothesis that MAO-B concomitantly affects locomotor responses in a novel inescapable open field and nicotine intake. Male wild-type (WT) and MAO-B KO mice were placed in an inescapable open field and their horizontal locomotor activity was measured for 30 min per day for 5 days. MAO-B KO mice exhibited impaired within-session habituation of locomotor activity, as compared to WT mice. Separate groups of male WT and MAO-B KO mice were individually housed in their home cages with two water bottles. One of the bottles contained tap water and the other contained nicotine (0, 3.125, 6.25, 12.5, 25, 50 or 100 micro g/ml). The total amount of water and nicotine solution consumed was measured every three days for 16 days. MAO-B KO mice and WT mice consumed equal amounts of nicotine and exhibited comparable concentration-dependent nicotine preference and aversion over a period of 16 days. The data suggest that the absence of MAO-B impairs the ability of mice to habituate in the inescapable environment, but does not alter their nicotine intake.

Three-dimensional ultrasound diagnosis of Larsen syndrome with further characterization of neurological sequelae

Larsen syndrome consists of skeletal dysplasia with multiple joint dislocations and a characteristic facies. The basis of this abnormality is a generalized mesenchymal disorder involving connective tissues. We describe our findings in a woman who was referred at 28 weeks' gestation due to multiple fetal anomalies suspected initially at an 18-week ultrasound examination. On three-dimensional (3D) ultrasound we found the fetus had bilateral genu recurvatum. Further 3D examination at 36 weeks confirmed the lower limb anomaly and revealed facial anomalies that led to the diagnosis of Larsen syndrome. An elective Cesarean section was performed at 38 weeks' gestation to minimize neurological sequelae. Magnetic resonance imaging was performed postnatally and showed pachygyria, colpocephaly and agenesis of the corpus callosum. In this case, 3D ultrasound facilitated the prenatal diagnosis of Larsen syndrome. A careful prenatal investigation for other associated anomalies such as those of the cardiovascular or neurological systems is warranted with this diagnosis. These associated lesions are likely to have a greater impact on prognosis than the classic symptoms of Larsen syndrome and a collaborative approach is necessary to optimize delivery and postnatal management of an affected fetus.

Heart rate dynamics in monoamine oxidase-A- and -B-deficient mice

Heart rate (HR) dynamics were investigated in mice deficient in monoamine oxidase A and B, whose phenotype includes elevated tissue levels of norepinephrine, serotonin, dopamine, and phenylethylamine. In their home cages, spectral analysis of R-R intervals revealed more pronounced fluctuations at all frequencies in the mutants compared with wild-type controls, with a particular enhancement at 1-4 Hz. No significant genotypic differences in HR variability (HRV) or entropies calculated from Poincaré plots of the R-R intervals were noted. During exposure to the stress of a novel environment, HR increased and HRV decreased in both genotypes. However, mutants, unlike controls, demonstrated a rapid return to baseline HR during the 10-min exposure. Such modulation may result from an enhanced vagal tone, as suggested by the observation that mutants responded to cholinergic blockade with a decrease in HRV and a prolonged tachycardia greater than controls. Monoamine oxidase-deficient mice may represent a useful experimental model for studying compensatory mechanisms responsible for changes in HR dynamics in chronic states of high sympathetic tone.

Increased baroreceptor response in mice deficient in monoamine oxidase A and B

The recent development of mice doubly deficient for monoamine oxidase A and B (MAO-A/B, respectively) has raised questions about the impact of these mutations on cardiovascular function, in so far as these animals demonstrate increased tissue levels of the vasoactive amines serotonin, norepinephrine, dopamine, and phenylethylamine. We recorded femoral arterial pressures and electrocardiograms in adult MAO-A/B-deficient mice during halothane-nitrous oxide anesthesia as well as 30 min postoperatively. During both anesthesia and recovery, systolic, diastolic, and mean arterial pressures were 10-15 mmHg lower in MAO-A/B-deficient mice compared with normal controls (P < 0.01). Mutants also showed a greater baroreceptor-mediated reduction in heart rate in response to hypertension after intravenous pulses of phenylephrine or angiotensin II. Tachycardia elicited in response to hypotension after nitroprusside was greater in mutants than in controls. Heart rate responsiveness to changes in arterial pressure was abolished after administration of glycopyrrolate, with no differences in this phenomenon noted between genotypes. These data suggest that prevention of hypertension may occur in chronic states of catecholaminergic/indoleaminergic excess by increased gain of the baroreflex.

Modulation of [3H]quinpirole binding at striatal D2 dopamine receptors by a monoamine oxidaseA-like site: evidence from radioligand binding studies and D2 receptor- and MAO(A)-deficient mice

[3H]Quinpirole is a dopamine agonist with high affinity for the D2 and D3 dopamine receptors. A variety of monoamine oxidase inhibitors (MAOIs) inhibit equilibrium binding of [3H]quinpirole binding in rat striatal membranes suggesting that MAOIs interact with a novel binding site that is labeled by [3H]quinpirole or that allosterically modulates [3H]quinpirole binding. To determine whether the D2 receptor is essential for [3H]quinpirole binding and/or modulation of [3H]quinpirole binding by MAOIs, D2 receptor-deficient mice were studied. [3H]Quinpirole binding was decreased in D2 receptor-deficient mice to 3% of that observed in wild-type controls indicating that [3H]quinpirole binding is associated with the D2 dopamine receptors. Then, in an attempt to label the site mediating the modulation of [3H]quinpirole binding, binding of the MAOI [3H]Ro 41-1049 was characterized in rat striatal membranes. [3H]Ro-41-1049 labeled a single binding site with a pharmacological profile with respect to MAOIs that was similar to both [3H]quinpirole binding (Spearman r=0.976) and MAO(A) activity. To determine whether MAO(A) plays a role in the modulation of [3H]quinpirole binding by MAOIs, MAO(A)-deficient mice were examined. In these mice, [3H]Ro-41-1049 binding was decreased to 7% of wild-type control. [3H]Spiperone binding was unaltered. Spiperone-displaceable [3H]quinpirole binding was decreased to 43% of wild-type control; however, the remaining [3H]quinpirole binding in MAO(A)-deficient animals was inhibited by Ro 41-1049 similar to wild-type. [3H]Ro-41-1049 binding was not decreased in D2 receptor-deficient mice. These data suggest that [3H]Ro-41-1049 labels multiple sites and that MAOIs modulate [3H]quinpirole binding to the D2 receptor via interactions at a novel, non-MAO binding site with MAO(A)-like pharmacology.

Biochemical, behavioral, physiologic, and neurodevelopmental changes in mice deficient in monoamine oxidase A or B

The availability of mutant mice that lack either MAO A or MAO B has created unique profiles in the central and peripheral availability of serotonin, norepinephrine, dopamine, and phenylethylamine. This paper summarizes some of the current known phenotypic findings in MAO A knock-out mice and contrast these with those of MAO B knock-out mice. Differences are discussed in relation to the biochemical, behavioral, and physiologic changes investigated to date, as well as the role played by redundancy mechanisms, adaptational responses, and alterations in neurodevelopment.

Yang-gan-wan protects mice against apoptosis induced by anti-Fas antibody (Jo2)

We investigated the protective effect of yang-gan-wan (YGW, Pro-Liver pill), a Chinese herbal remedy, against liver apoptosis (programmed cell death) induced by anti-Fas antibody (Jo2). Mice were pretreated daily with 200 mg/kg YGW for 14 days before treatment with 10 microg/20 kg body weight Jo2. YGW significantly reduced the elevated activity of alanine aminotransferase (ALT) and also reduced the elevated activity of sorbitol dehydrogenase (SDH) produced 4 hrs after treatment with Jo2. YGW also increased the survival of mice treated with Jo2 by about 1 hr in 11 out of 16 mice (69%). Most of the mice died 9 hrs after Jo2 injection. This study demonstrates that YGW has protective effects against liver apoptosis induced by Jo2.

Effects of carboxyl-terminal truncations on the activity and solubility of human monoamine oxidase B

Monoamine oxidase is an outer mitochondrial membrane protein that catalyzes the deamination of a number of neurotransmitters and dietary amines. To determine the roles of the carboxyl-terminal amino acids on the activity and solubility of human monoamine oxidase (MAO B), 10 sequential mutants were made with stop codons at amino acid positions 511, 504, 498, 492, 486, 481, 476, 467, 417, and 397, respectively. All truncated mutants were expressed in Sf21 insect cells using baculovirus, and the enzyme kinetic parameters were determined. Truncations at amino acid positions 511, 504, and 498 slightly decreased MAO B catalytic activity and had no significant changes on deprenyl inhibition. Further deletions up to amino acid 417 decreased the specific activity 10--100-fold without significant changes of the K(m) for phenylethylamine or dopamine or the IC(50) for deprenyl and clorgyline. The truncation mutant C397, which lacks covalently attached FAD, was inactive. Progressive carboxyl-terminal truncations up to position 481 were correlated with increased solubility of MAO B mutants. 47% of the activity of the truncated C481 was found in the 105,000 x g supernatant in the absence of detergent. However, further truncated mutants, C476, C467, and C417, remained associated with the membrane fraction. In contrast to crude homogenate, the water-soluble C481 mutant was rapidly inactivated at 4 degrees C and 37 degrees C, which indicates that the membrane environment is required for the stability of MAO B. Expression of the green fluorescent protein-MAO B C481 fusion protein revealed that this mutant was located in the cytoplasm, whereas its counterpart in MAO A, truncated mutant C490, was located on the mitochondria. These results suggest that the carboxyl-terminal amino acid residues 417--520 of MAO B are not directly involved in the active site but are required for maintaining the appropriate conformation and interaction with the outer mitochondrial membrane. The different solubilities of the various carboxyl-terminal truncation mutants indicate that the interaction of MAO B with mitochondrial membrane is not simply anchoring through the carboxyl-terminal hydrophobic tail. Further, our results suggest that the carboxyl-terminal of MAO A and B plays different roles in mitochondrial attachment.

In utero progressive pulmonary stenosis successfully treated with transcatheter intervention after delivery

It is unclear whether pulmonary stenosis with intact ventricular septum is a secondary cardiac malformation. We report an infant with pulmonary stenosis (diagnosed by fetal echocardiography) with progressive obstruction in late gestation who presented with increasing transvalvular pressure gradients (15 mm Hg at 22 weeks' gestation to 47 mm Hg at 35 weeks). The tricuspid/mitral valve annulus ratio decreased from 1.25 at 24 weeks' gestation to 0.96 at 33 weeks. At 38 weeks' gestation, a male infant weighing 3,524 g, with Apgar scores of 9 and 9 at 1 and 5 minutes, respectively, was delivered by cesarean section. Critical pulmonary stenosis was confirmed by postnatal catheterization. These findings support the postulation that pulmonary stenosis is a progressive disorder. After percutaneous balloon dilatation, the transvalvular pressure gradient decreased and the right ventricular cavity increased gradually. The transvalvular pressure gradient had decreased to 15 mm Hg and the tricuspid/mitral valve annulus ratio was 0.93 at the age of 2 years.

Regulation of human monoamine oxidase B gene by Sp1 and Sp3

The human monoamine oxidase (MAO) B plays a major role in the degradation of biogenic and dietary amines such as phenylethylamine, benzylamine, dopamine, and tyramine. We previously showed that the -246/-99 MAO B promoter region exhibited the highest activity and contained two clusters of overlapping Sp1 sites, a CACCC element and a TATA box. Here, using a series of 10 deletion constructs of the 2-kilobase pair 5'-flanking sequence, we identified additional potential regulatory elements, including activator proteins 1 and 4, CAAT, GATA, upstream stimulatory factor (USF), estrogen receptor (ER), and sex-determining region Y-box 5 (SOX5). Analysis of nine site-directed mutations of -246/-99 region reveals that both clusters of Sp1 sites contribute positively whereas the CACCC element contributes negatively to the transcriptional activity. Gel shift analysis demonstrates that in addition to Sp1, Sp3 can interact with both clusters of Sp1 sites. Cotransfection experiments show that Sp1 and its closely related family member Sp4 can trans-activate MAO B promoter activity through the proximal cluster of Sp1 sites and its activation can be repressed by the over-expression of Sp3 and a related family member BTEB2. These results suggest that the binding to the overlapping Sp1 sites by various members of Sp family is important for the regulation of the MAO B gene expression.

First-trimester Down's syndrome screening by fetal nuchal translucency measurement in Taiwan

BACKGROUND

Fetal nuchal translucency (NT) measurement is now widely used in many Western countries as a screening tool for Down's syndrome during the first trimester. However, at present there is no data on its use in Taiwan. The purpose of the present study was to evaluate the efficacy of NT measurement in first-trimester Down's syndrome screening in Taiwan.

METHODS

We conducted a prospective study from October 1997 to May 1999. Sonographic measurement of fetal NT was performed in 1,249 fetuses at 9-14 weeks of gestation. Transabdominal ultrasound scanning was performed to obtain a sagittal section of the fetus for measuring the crown-rump length (CRL) and the maximum thickness of the subcutaneous translucency between the skin and the soft tissue overlying the cervical spine. Two different cut-off points were used for screening: a fixed cut-off point of at least 2.5 mm and a CRL-related cut-off point. In the latter method, fetuses with an NT measurement in the 95th percentile were considered at high risk for Down's syndrome.

RESULTS

Three fetuses had Down's syndrome, with NT measurements of 2.1 mm, 2.7 mm, and 4.0 mm. The false positive rates for the fixed cut-off point and CRL-related cut-off point were 6.3% and 4.6%, respectively. Both methods had a sensitivity of 66.7%. However, the screening program using the CRL-related cut-off point had two advantages: a higher specificity (95.5% vs 93.8%) and a more reasonable distribution pattern for screening.

CONCLUSION

This study showed that NT measurement is a potential screening tool for Down's syndrome during the first trimester in Taiwan. Using CRL-related cut-off points for screening is more reasonable than using a fixed cut-off point.

Substrate and inhibitor specificities for human monoamine oxidase A and B are influenced by a single amino acid

Monoamine oxidase (MAO) is responsible for the oxidation of biogenic and dietary amines. It exists as two isoforms, A and B, which have a 70% amino acid identity and different substrate and inhibitor specificities. This study reports the identification of residues responsible for conferring this specificity in human MAO A and B. Using site-directed mutagenesis we reciprocally interchanged three pairs of corresponding nonconserved amino acids within the central portion of human MAO. Mutant MAO A-I335Y became like MAO B, which exhibits a higher preference for beta-phenylethylamine than for the MAO A preferred substrate serotonin (5-hydroxytryptamine), and became more sensitive to deprenyl (MAO B-specific inhibitor) than to clorgyline (MAO A-specific inhibitor). The reciprocal mutant MAO B-Y326I exhibited an increased preference for 5-hydroxytryptamine, a decreased preference for beta-phenylethylamine, and, similar to MAO A, was more sensitive to clorgyline than to deprenyl. These mutants also showed a distinct shift in sensitivity for the MAO A- and B-selective inhibitors Ro 41-1049 and Ro 16-6491. Mutant pair MAO A-T245I and MAO B-I236T and mutant pair MAO A-D328G and MAO B-G319D reduced catalytic activity but did not alter specificity. Our results indicate that Ile-335 in MAO A and Tyr-326 in MAO B play a critical role in determining substrate and inhibitor specificities in human MAO A and B.

Biochemical effects of the monoamine neurotoxins DSP-4 and MDMA in specific brain regions of MAO-B-deficient mice

Previous studies reported that drugs acting as monoamine oxidase (MAO)-B inhibitors prevented biochemical effects induced by the neurotoxins N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) and 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy"). In this study, we administered DSP-4 (50 mg/kg) or MDMA (50 mg/kg x 2, 2 h apart) to MAO-B deficient mice. Monoamine content in various brain regions (cerebellum, frontal cortex, hippocampus, hypothalamus, striatum, substantia nigra) was assayed 1 week after neurotoxin administration. Injection of DSP-4 to wild-type mice caused a marked norepinephrine (NE) loss in specific brain regions. Unexpectedly, DSP-4 caused similar effects in MAO-B-deficient and in wild-type mice in all brain regions investigated. These results suggest that MAO-B is not involved in DSP-4 toxicity. In wild-types, the neurotoxin MDMA induced both serotonin (5HT) and dopamine (DA) depletion in specific brain areas. In MAO-B-deficient mice, 5HT depletion observed in wild-types did not occur. In contrast, MDMA produced a more pronounced DA loss in knockout mice compared with wild-types. The present findings, together with previous data obtained using selective enzyme inhibitors, suggest that MAO-B is not involved in the mechanism of action of DSP-4, whereas it plays opposite roles in MDMA-induced DA and 5HT depletions.

Yang-Gan-Wan protects mice against experimental liver damage

The hepatoprotective effect of Yang-Gan-Wan (YGW, Pro-Liver pill), a Chinese herbal remedy, was investigated in mice that were treated with allyl alcohol (AlOH), acetaminophen (AA) or carbon tetrachloride (CCl4). Mice were pretreated daily with 200 mg/kg YGW for 10, 14 and 18 days before treatment with 85 mg/kg AlOH, 475 mg/kg AA or 20 microl/kg CCl4, respectively. YGW dramatically abolished the elevated activities of alanine aminotransferase (ALT) and sorbitol dehydrogenase (SDH) and reduced the necrosis induced by AlOH. YGW also decreased the elevated activities of ALT and SDH and reduced the necrosis induced by AA and CCl4. This study demonstrates that YGW has protective effects against liver damage induced by AlOH, AA, and CCl4.

2-Naphthylamine, a compound found in cigarette smoke, decreases both monoamine oxidase A and B catalytic activity

Cigarette smokers exhibit a lower monoamine oxidase (MAO; EC 1.4.3.4) activity than nonsmokers. MAO is located in the outer membrane of mitochondria and exists as two isoenzymes, MAO A and B. MAO A prefers 5-hydroxytryptamine (serotonin), and MAO B prefers phenylethylamine (PEA) as substrate. Dopamine is a substrate for both forms. 2-Naphthylamine is a carcinogen found in high concentrations in cigarette smoke. The results of this study show that 2-naphthylamine has the ability to inhibit mouse brain MAO A and B in vitro by mixed type inhibition (competitive and non-competitive). The Ki for MAO A was determined to be 52.0 microM and for MAO B 40.2 microM. The inhibitory effect of 2-naphthylamine on both MAO A and B catalytic activity, supports the hypothesis that smoking decreases MAO activity in vivo, instead that smokers with lower MAO activity are more prone to become a smoker.

Prenatal diagnosis and genetic analysis of type I and type II thanatophoric dysplasia

Thanatophoric dysplasia (TD) is one of the most common neonatal lethal skeletal dysplasias. Prenatal sonographic and molecular genetic diagnoses of three cases of TD type I (TD1) and one case of TD type II (TD2) are presented here. Two fetuses of TD1 were characterized by polyhydramnios, macrocephaly, short limbs, a narrow thoracic cage and curved short femora, but without a cloverleaf skull at 27 and 31 weeks' gestation, respectively. The third fetus with TD1 was, however, not associated with macrocephaly, polyhydramnios, chest narrowing and severe femoral bowing on prenatal ultrasound at 18 weeks' gestation. The TD2 fetus was characterized by polyhydramnios, short limbs, a narrow thoracic cage, straight short femora, hydrocephalus and a cloverleaf skull at 24 weeks' gestation. Three-dimensional ultrasound was able to enhance the visualization of thickened, redundant skin folds and craniofacial and limb deformities associated with TD. Molecular analysis of the fibroblast growth factor receptor 3 (FGFR3) gene by restriction enzyme digestion analysis and direct sequencing using cultured amniotic fluid cells or cord blood cells revealed a missense mutation of 742C-->T (Arg248Cys) in all cases with TD1 and a missense mutation of 1948A-->G (Lys650Glu) in the case with TD2. The present report shows that adjunctive applications of molecular genetic analysis of the FGFR3 gene and three-dimensional ultrasound are useful for prenatal diagnosis of TD.

Three-dimensional ultrasonography in early pregnancy

Three-dimensional ultrasound was introduced into clinical use over a decade ago. Early attempts on three-dimensional ultrasound were primitive and limited to experimental use only. Recently, it was used as a powerful tool to display three-dimensional fetal appearance and assess normal and pathological conditions. Because of the improvement in image resolution and reconstruction speed, three-dimensional ultrasound is now more and more popular in many centers, and used commonly as an adjunct in prenatal diagnosis. Indeed, a skillful sonographer may usually make the correct diagnosis of fetal anomaly with simply two-dimensional ultrasound. Nonetheless, the situation is gradually changing, because some anomalies have been diagnosed only based on the findings of three-dimensional ultrasound. In spite of that, the application of three-dimensional ultrasound is still less discussed in early pregnancy. In this article, the authors clarify the capability of three-dimensional ultrasound in different anatomic areas, and catalog its clinical merits in the early pregnancy to date. We also present the safety guidelines for its use in the first trimester.

Current awareness in prenatal diagnosis

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of prenatal diagnosis. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General Interest; 3 Normal Fetal Development; 4 Gametogenesis and Pre-implantation Diagnosis; 5 First Trimester Diagnosis; 6 Second Trimester Diagnosis; 7 Fetal Diagnosis by Ultrasound and Other Imaging; 8 Maternal Screening; 9 Screening for Carriers of Genetic Abnormality; 10 Technological Developments; 11 Confined Placental Mosaicism and Uniparental Disomy; 12 Molecular Cytogenetics; 13 Fetal Cells in Maternal Circulation; 14 Fetal Therapy; 15 Psychosocial Aspects; 16 Epidemiology and Environmental Factors; 17 Developmental Pathology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted.

Analysis of the pharmacological and molecular heterogeneity of I(2)-imidazoline-binding proteins using monoamine oxidase-deficient mouse models

The I(2) subgroup of imidazoline-binding sites was identified as monoamine oxidases (MAOs), but it is unclear whether there are I(2)-binding sites located on proteins distinct from MAOs. To address this issue, we characterized I(2)-binding proteins in liver and brain of wild-type and MAO A- and MAO B-deficient mice. I(2)-binding sites were identified using [(3)H]idazoxan and the photoaffinity adduct 2-[3-azido-4-[(125)I]iodophenoxyl]methylimidazoline ([(125)I]AZIPI). [(3)H]Idazoxan labeled binding sites with ligand recognition properties typical of I(2) sites in both brain and liver of wild-type mice. High-affinity, specific [(3)H]idazoxan binding were not altered in MAO A knockout (KO) mice. In contrast, [(3)H]idazoxan binding was completely abolished in both liver and brain of MAO B KO mice. In wild-type mice, [(125)I]AZIPI photolabeled three proteins with apparent molecular masses of approximately 28 (liver), approximately 61 (brain), and approximately 55 kDa (liver and brain). The photolabeling of each protein was blocked by the imidazoline cirazoline (10 microM). Photolabeling of the approximately 61- and approximately 55-kDa proteins was not observed in MAO A and B KO mice, respectively. In contrast, photolabeling of the liver approximately 28-kDa protein was still observed in MAO-deficient mice, indicating that this protein is unrelated to MAOs. These data indicate that I(2) imidazoline-binding sites identified by [(3)H]idazoxan reside solely on MAO B. The binding sites on MAO A and the liver approximately 28-kDa protein may represent additional subtypes of the family of the imidazoline-binding sites.

Phe(208) and Ile(199) in human monoamine oxidase A and B do not determine substrate and inhibitor specificities as in rat

It has been reported previously that reciprocally switching Phe(208) and Ile(199) in rat monoamine oxidase (MAO) A and B, respectively, was sufficient to switch their substrate and inhibitor preferences. In this study, the same mutants were made in the human forms of MAO. When compared with MAO A, MAO A-F208I showed a sixfold decrease in the specificity constant k(cat)/K(m) for both the MAO A- and the MAO B-preferring substrates 5-hydroxytryptamine and beta-phenylethylamine, respectively. The reciprocal point mutant MAO B-I199F had no effect on substrate affinity. To investigate if the region neighboring these two residues is responsible for conferring preferences, we have also made chimeric constructs by reciprocally switching the corresponding amino acid segments 159-214 in MAO A and 150-205 in MAO B. Chimerics MAO AB(159-214)A and MAO BA(150-205)B had small changes in K(m) and IC(50) values when compared with MAO A and B, respectively, but did not exhibit a preference switch. The results suggest that Phe(208) in MAO A and amino acid segments 159-214 and 150-205 in MAO A and B, respectively, influence the enzyme active site. However, substrate and inhibitor preferences of human MAO A and B are not determined by the respective residues Phe(108) and Ile(199) as in rat MAO nor by their neighboring regions.

Antenatal diagnosis of congenital hepatoblastoma in utero

A fetus with a huge hepatic tumor was detected by sonography at 36 weeks of gestation. The mass appeared as a single, solid and polylobular tumor located in the right lobe of the liver. Foci of hemorrhage, necrosis and some tiny calcifications were seen. The adjacent right kidney appeared normal but was displaced. The right adrenal gland was not visualized. Three-dimensional power Doppler sonography further depicted the corresponding vascular anatomy of the tumor, including its vascularization pattern and blood supply. The tumor was situated to the right of the umbilical vein and portal sinus, possibly deriving its blood supply from the portal circulation. The fundamental findings suggested the diagnosis of hepatoblastoma by exclusion of other possibilities. The baby was delivered by Cesarean section at 36 weeks' gestation, due to signs of fetal distress. Unfortunately, hypotension, tachycardia, and tachypnea developed shortly after birth. Surgical intervention was performed, but intractable bleeding occurred intra-operatively. The infant died at 6 days of age. Autopsy confirmed the diagnosis of hepatoblastoma. We believe this is the first reported case of the antenatal diagnosis of congenital hepatoblastoma.

Prenatal depiction of angioarchitecture of an aneurysm of the vein of Galen with three-dimensional color power angiography

A fetus with a large supratentorial cyst and cardiomegaly was encountered at 33 weeks of gestation. The cyst appeared as an aneurysmal, fluid-filled structure extending posteriorly with a finger-like appendage. Using color flow mapping, we disclosed rapid in-and-out blood flow with marked turbulence within the cyst. For evaluation of its blood supply and venous drainage of the vascular malformation, a three-dimensional reconstruction of the power Doppler image was conducted. The results revealed that the vascular malformation was supplied by a small contralateral aneurysm from the branches of Willis' circle, draining posteriorly into an abnormal falcine sinus and then into the superior sagittal sinus. No other fetal abnormality such as hydrocephalus or hydrops was discovered. The prenatal diagnosis of an aneurysm of the vein of Galen was made on the basis of the gray-scale, color Doppler findings, and also the angioarchitecture obtained by three-dimensional power Doppler imaging. The woman was admitted at 37 weeks of gestation due to labor onset and delivered the baby via the vaginal route without complication. Postnatal angiography and magnetic resonance imaging confirmed the diagnosis of an aneurysm of the vein of Galen, and the angioarchitecture depicted it before birth. We suggest that three-dimensional power Doppler ultrasonography may assist in the diagnosis of an aneurysm of the vein of Galen, and precisely delineate the complicated corresponding vasculature. This may guide postnatal management and predict the prognosis more accurately.

Maternal serum screening for down syndrome by using alpha-fetoprotein and human chorionic gonadotropin in an asian population. a prospective study

The purpose of the present study is to evaluate the efficacy of second-trimester maternal serum screening program by using alpha-fetoprotein (AFP) and total human chorionic gonadotropin (hCG) in an Asian population. During June 1994 to July 1998, we conducted a prospective study of serum screening protocol for Down syndrome. The cut-off point for a positive result in this analysis was a risk of >/=1/270. A total of 17,742 pregnant women with singleton pregnancy were screened, and 1,153 (6.5%) had positive result. Sixteen of the 17,742 pregnancies had Down syndrome, and 10 of them had positive result. The positive rate and detective rate for Down syndrome were 6.5 and 62.5%, respectively. However, the detective rate will reduce to 47.6% after being adjusted by age-specific risk. It is indicated that the double-marker test using AFP and total hCG is an effective screen strategy for second-trimester detection of Down syndrome in Asian women.

Second trimester maternal serum hCG level in an Asian population: normal reference values by ultrasound dating

OBJECTIVE

To establish normative data of maternal serum chorionic gonadotropin (hCG) during the second trimester in an Asian population.

METHODS

We measured the maternal serum hCG levels in 17,955 normal singleton pregnancies between 15 and 21 weeks of gestation. The gestation age was estimated by measurement of fetal biparietal distance (BPD) in all cases. Median values of hCG at various gestational weeks were calculated and the values of hCG were converted to multiple of median (MoM). The incidences of low MoM value and high MoM value were also calculated.

RESULTS

The mean and median values of hCG were 57,153 mIU/ml and 50,120 mIU/ml, respectively, at 15 weeks of gestation and then decreased to 30,898 mIU/ml and 26,226 mIU/ml, respectively, at 21 weeks. We found 8.6% and 9.4% of normal singleton pregnancies have hCG MoM values >2.0 MoM and <0.5 MoM, respectively.

CONCLUSIONS

Our report provides a normal reference data of second trimester maternal hCG levels by ultrasound dating in an Asian population.

Ginkgo biloba abolishes aggression in mice lacking MAO A

Mice deficient in monoamine oxidase A (MAO A) have increased brain levels of serotonin (5-HT) and norepinephrine and show enhanced aggression. We used MAO A knock-out (KO) mice as a model to study the effect of ginkgo biloba (EGb) on aggression. When EGb was administered to MAO A KO mice, their aggressive behavior in resident-intruder confrontations was reduced to levels seen in wild types. EGb did not affect the locomotive behavior of MAO A KO mice, which suggests that its effects on aggression were not due to sedation. EGb caused a significant 16.9% decrease in [3H]ketanserin binding to 5-HT2A receptors in the frontal cortex of MAO A KO mice but did not change the receptor affinity for [3H]ketanserin. This suggests that the antiaggressive effect of EGb may be mediated by 5-HT2A receptors and that EGb may be developed as a novel antiaggressive agent.