MR imaging findings of enteroviral encephaloymelitis: an outbreak in Taiwan

BACKGROUND AND PURPOSE

An outbreak of enterovirus infection occurred in Taiwan from late spring to early fall of 1998. Most of the pediatric infections presented as hand-foot-mouth disease (HFMD) and herpangina. A small portion of patients had symptoms of polio-like encephalitis and paralysis. The purpose of this study was to review the MR imaging findings in CNS involvement of enterovirus infection.

METHODS

Twenty patients who had HFMD and clinical encephalitis were examined with MR imaging. T1-weighted and T2-weighted MR images were obtained. From the rectum, throat, CSF, and peripheral blood, the presence of enterovirus 71 (EV 71) was determined by virus culture, immunofluorescent microscopy, immunologic dot blotting, and reverse-transcription polymerase chain reaction.

RESULTS

MR imaging studies of 20 patients showed hyperintensity in the brain stem and spinal cord in 15 patients, as seen on T2-weighted images. The major CNS lesions were in the medulla oblongata, pons, midbrain, and the dentate nuclei of the cerebellum. In some cases, the lesions involved the spinal cord (three cases) as well as the thalamus (two cases) and putamina (one case). Five patients had normal MR imaging results. After the appropriate management for tachycardia and tachypnea, 18 patients recovered within 1 to 2 weeks. In the follow-up MR imaging examination of five patients, the lesions completely disappeared within 2 weeks to 2 months. In two patients who were still respirator-dependent, MR imaging showed the tissue destruction in the posterior portions of the medulla, pons, and the ventral horns of cervical spinal cord. In one patient, most of midbrain was damaged. The presence of EV 71 was detected in specimens from 18 patients.

CONCLUSION

Because EV 71 was identified in 18 patients, and no other virus was detected, EV 71 was determined to be the major causative agent of this encephalomyelitis. Brain stem and cervical spinal cord involvement are characteristic findings of enteroviral encephalomyelitis.

3-hydroxy-3-methylglutaric aciduria presenting with Reye like syndrome: report of one case

We report the case of a patient with 3-hydroxy-3-methylglutaric aciduria who presented with a repeat attack of Reye like syndrome clinically. Vomiting and somnolence, generalized tonic and clonic convulsions with hepatomegaly, hyperammonemia, liver function impairment, and mild metabolic acidosis were the presenting signs. 3-hydroxyisovaleric, 3-methylglutaric, 3-methylglutaconic and 3-hydroxy-3-methylglutaric acids were detected in the urine by gas chromatography-mass spectrometry. 3-methylglutarylcarnitine was also identified in the urine by fast atom bombardment and tandem mass spectrometry. Therefore, the possibility of metabolic disease should be considered in neonates and infants with repeat attacks of Reye like syndrome and a history of similarly affected siblings.

Agnathia in one of heterozygous twins

Agnathia is a rare developmental field complex in humans with the structural defects limited to the craniofacial region. This rare complex can occur in combination with holoprosencephaly and situs inversus. Here we report on a pair of twins. The female infant had characteristic malformation complex of agnathia, while her twin brother showed normal appearance eventually. This case is the first reported case of isolated agnathia in twins.

Requirement for cell-to-cell contact in Epstein-Barr virus infection of nasopharyngeal carcinoma cells and keratinocytes

Two nasopharyngeal carcinoma (NPC) cell lines and one keratinocyte cell line could be infected with Epstein-Barr virus (EBV) by cocultivation with virus-producing cells but not by cell-free virus. Using porous culture inserts to manipulate the cell-to-cell contact, we demonstrated that contact between EBV donor B cells and EBV recipient epithelial cells was required for the infection. Cell-to-cell contact not only provided a CR2-independent route of infection but also enhanced CR2-mediated infection in a synergistic manner. Activity of two EBV promoters (Cp and Wp) and expression of EBNA2 were detected in the infected population. A small proportion of the infected cells spontaneously entered an EBV lytic state, which could be induced prominently by chemical treatment. This study provides information on how EBV may infect epithelial cells in vivo, such as at the onset of NPC development.

Molecular characterization of secretor type alpha(1, 2)-fucosyltransferase gene deficiency in the Philippine population

We analyzed the seven mutations which are responsible for the deficiency of the secretor type alpha(1,2)-fucosyltransferase gene product, Se enzyme, in the Philippine population. One hundred and one unrelated Filipinos in Taiwan were studied. A new mutation, a 3-base pair deletion from nt 688 through 690, was found in two (0. 1%) of 202 chromosomes. The frequencies of six other mutated alleles were as follows: 71/202 (35.2%) were cDNA 385 A-->T missensed mutation (se2), 28/202 (13.9%) were C571T nonsense mutation (se3), 16/202 (7.9%) were G849A nonsense mutation (se4), 4/202 (1.9%) were G428A nonsense mutation (se1), and 81/202 (40.1%) were wild-type allele (Se). No C628T nonsense mutations (se5) or fusion genes of pseudogene and FUT2 gene (se 6) were found in this population. For the molecular basis of phenotype Le(a+ b-): eight cases had se2/se2, six cases had se2/se3, two cases had se3/se4, one case was homozygous of se4, one case was se3/se1, and two cases were se2/se7. For the Le(a+ b+) phenotype: four cases had se2/se2, two cases had se2/se3, one case was se3/se3, and one case was se2/se4. For the Le(a- b+) phenotype: 16 cases were Se/Se, 21 cases were Se/se2, six cases were Se/se3, five cases were Se/se4, and two cases had Se/se1. Our results suggest that the genotypes of the alpha(1, 2)-fucosyltransferase gene in phenotypes Le(a+ b+) and Le(a+ b-) are the same. Other factors that play important roles may cause the differences between these two phenotypes. Several hotspot mutations in the alpha(1,2)-fucosyltransferase gene are responsible for the nonsecretor phenotype.

Effects of veratrine and paeoniflorin on the isolated rat aorta

The interactions and mechanisms between veratrine and paeoniflorin on the isolated rat aorta were studied. Veratrine (1x10(-6) to 1x10(-4) g/ml) could induce contraction on the isolated rat aorta in a concentration-related manner. Paeoniflorin had no effect on the isolated rat aorta. Pretreatment with prazosin (1x10(-6) M) and nifedipine (1x10(-6) M) but not yohimbine (1x10(-5) M) could decrease the tension of contraction induced by veratrine (1x10(-4) g/ml). Sodium nitroprusside (1x10(-4) M) could inhibit the contraction induced by veratrine (1x10(-4) g/ml) with or without endothelium, whereas methylene blue (5x10(-5) M) could increase the contraction induced by veratrine (1x10(-4) g/ml). Treatment with veratrine (1x10(-4) g/ml) could decrease the tension of contraction induced by norepinephrine (1x10(-6) M) or phenylephrine (1x10(-4) M). The inhibition of veratrine on norepinephrine-induced contraction was potentiated by L-arginine (1x10(-4) M) and reversed by L-NAME (1x10(-5) M). Paeoniflorin (1x10(-4) M) could decrease the tension of contraction induced by veratrine (1x10(-4) g/ml) and methylene blue (5x10(-5) M). The inhibition of paeoniflorin on veratrine was more potent on rat isolated aorta with endothelium than without endothelium. Ryanodine (1x10(-5) M) and Ca2+ -free medium could inhibit methylene blue-induced contraction. From the above results, the relaxation of veratrine on the norepinephrine-induced contraction might be related to the increase of NO and cGMP. The contraction of veratrine on the isolated rat aorta was via the increase of intracellular calcium which was inhibited by paeoniflorin.

Molecular analysis of secretor type alpha(1,2)-fucosyltransferase gene mutations in the Chinese and Thai populations

BACKGROUND

The human Lewis histo-blood group system belongs to a family of structurally related oligosaccharides. The mutations of fucosyltransferase genes alpha(1,2)-fucosyltransferase (FUT2 or Se) and alpha(1,3/1,4)-fucosyltransferase (FUT3 or Le), are responsible for the polymorphism of Lewis blood group phenotypes. However, a population study of the FUT2 mutation in Chinese and Thais has not yet been done, and there is some controversy about the phenotypes of Le(a+b+) and Le(a+b-).

STUDY DESIGN AND METHODS

One hundred twentyfour Chinese and 70 Thais were phenotyped for Lea and Le(b). DNA samples were studied by polymerase chain reaction and then by a restriction enzyme digestion method to distinguish wild-type and six known mutations. Direct sequencing was done for controls and some uncertain cases.

RESULTS

A new mutation, C302T mutation, was found in 2 of 136 chromosomes in the Thai population; none were discovered in Chinese. The frequencies of the normal and six mutant alleles among Chinese and Thais, respectively, were as follows: 134 (54.0%) of 248 and 58 (41.4%) of 140 were wild-type (Se); 0 of 248 and 2 of 140 (both 1.4%) had the G428A mutation; 120 (48.4%) of 248 and 75 (53.6%) of 140 had the A385T mutation; 2 (0.81%) of 248 and 0 of 140 had the C571T mutation; and 1 (0.4%) of 248 and 3 (2.2%) of 140 had the G849A mutation. Only 1 Chinese (0.4%) of 248 had the C628T mutation, and none had fusion gene mutation.

CONCLUSION

The FUT2 genes encoding for the phenotypes Le(a+b+) and Le(a+b-) are the same. The function and character of the mutant enzyme may play an important role in the phenotype. The methods used in this study are clinically applicable in population studies of the FUT2 gene polymorphism to explore relationships among different ethnic groups and correlations between phenotype and genotype.

Early dexamethasone therapy and blood cell count in preterm infants

OBJECTIVE

To assess the effects of early postnatal dexamethasone therapy on hematologic values in preterm infants.

MATERIALS AND METHODS

We reviewed the hematologic data of 179 preterm infants who participated in a double-blind clinical trial of early postnatal dexamethasone therapy (<12 hours after birth) for the prevention of chronic lung disease. One group (86 infants) received saline and the other group (93 infants) received dexamethasone. Dexamethasone was given intravenously every 12 hours in tapering doses: 0.25 mg/kg on days 1 to 7, 0.12 mg/kg on days 8 to 14, 0.05 mg/kg on days 15 to 21, and 0.02 mg/kg on days 21 to 28. Blood samples were obtained on days 0, 3, 7, 10, 14, 21, and 28. None of the infants received prenatal steroid therapy.

RESULTS

Multiple regression analysis revealed significant differences in the values versus time curves of the white blood cell, neutrophil, lymphocyte, basophil, and eosinophil counts between the two groups. The white blood cell count was significantly higher in the dexamethasone group on days 7 through 14, and this was associated with significantly higher numbers of segmented neutrophils and band forms and significantly lower numbers of lymphocytes and eosinophils. The hematocrit and platelet counts were similar in the two groups throughout most of the trial. Except for platelet count, steroid therapy did not alter the hematologic values for infants with bacteremia.

CONCLUSION

Dexamethasone affects white blood cell, segmented neutrophil, lymphocyte, basophil, and eosinophil counts in neonates. This should be taken into consideration when evaluating preterm infants who are receiving dexamethasone.early dexamethasone therapy; neonatal blood count; preterm infant; respiratory distress syndrome.

P53 codon 72Arg polymorphism is not a risk factor for carcinogenesis in the chinese

The potential association of distinct polymorphism of the tumor suppressor gene p53, with an increased susceptibility to malignant transformation has been reported for various cancers. A polymorphism at codon 72 of p53 results in translation to either arginine (p53Arg) or proline (p53Pro), and recent study showed that Caucasian women with arginine form of p53 are more susceptible to HPV-associated carcinoma of the cervix. To examine whether arginine 72 could be a significant risk factor for tumor development, we used a PCR-based assay to analyze p53 genotypes of patients for several types of carcinoma. No significant difference in the frequency of p53Arg was found between normal and cancer patients, the results showed that the individuals homozygous for arginine variant were not at increased risk for cancer.

Glucose and insulin infusion versus kayexalate for the early treatment of non-oliguric hyperkalemia in very-low-birth-weight infants

Forty very low birth weight (VLBW) infants with non-oliguric hyperkalemia in the first few days after birth were enrolled in this study. They were randomly divided into 2 groups, regular insulin (RI) infusion group and kayexalate resin enema group. Therapy was administered when serum potassium level was greater than 6 mEq/L. None of these infants received blood transfusion during this study course. In RI group (n = 20), the ratio of infusion glucose to regular insulin was 10-15 gm glucose to 1 unit RI, and the glucose infusion rate was maintained at least 6 mg/Kg/min. In Kayexalate group (n = 20), the dose of Kayexalate was 1 gm/Kg body weight given rectally every four hours. All treatment discontinued after the serum potassium level returned to normal for 6 hours. The mean gestational ages were 27.4 +/- 1.8 weeks in RI group and 28.4 +/- 2.4 weeks in Kayexalate group, respectively. Mean birth weights were 935 +/- 259 gm (RI) and 1065 +/- 214 gm (Kayexalate). The ages at onset of hyperkalemia were 24.6 +/- 8.2 (RI) and 22.2 +/- 8.1 (Kayexalate) hours after birth. The mean urine outputs during the 8-hour interval prior to development of hyperkalemia were 5.4 +/- 1.3 (RI) and 5.5 +/- 0.9 (Kayexalate) ml/kg/min. The durations of hyperkalemia were 26.4 +/- 14.9 (RI) and 38.6 +/- 13.3 (Kayexalate) hours. The peak serum potassium levels during therapy were 7.3 +/- 0.9 and 7.4 +/- 0.6 mEq/L. The incidences of grade II and above intraventricular hemorrhage (IVH) were 15% (3/20) and 50% (10/20). The incidences of cardiac dysrhythmia were 5% (1/20) and 10% (2/20). Significantly shorter duration of non-oliguric hyperkalemia and lower incidence of IVH were noted in RI group, but there were no differences in the peak potassium level or the incidence of cardiac dysrhythmia between these two groups. We conclude that to use early continuous regular insulin infusion therapy for the treatment of non-oliguric hyperkalemia in VLBW infants is more effective than kayexalate in decreasing the duration of hyperkalemia and reducing the incidence of intraventricular hemorrhage.

Rapid diagnosis of common aneuploidies by quantitative fluorescent polymerase chain reaction

The most frequent autosomal aneuploidies in newborns involve chromosomes 21, 18, and 13. The pre- and postnatal detection of chromosome abnormalities has been almost exclusively performed by cytogenetic analysis. In this paper, we assess the diagnostic value of fluorescent polymerase chain reaction (PCR) using polymorphic small tandem repeats (STR). PCR products are distinguished via both size and fluorescence intensity to confirm the trisomy by either triallelic signals with similar fluorescence intensities or diallelic pattern with double-dose response. Compared with the relatively time-consuming and laborious classic cytogenetic analysis, this technique is rapid, inexpensive, and sensitive for the detection of trisomies 21, 18 and 13, particularly when the numbers of cells obtained from the prenatal diagnosis is limited or where cell culture fails. With greater samples tested and more STR markers available, this method will become more reliable. This study investigates the detection of aneuploides involving chromosomes 21, 18, and 13 by comparing quantitative fluorescent PCR with karyotyping performed by conventional cytogenetics. The results obtained by the two techniques were concordant in all trisomy cases of this study.

No association of alpha-2 macroglobulin gene five-nucleotide deletion with AD in Taiwan Chinese

The alpha-2 macroglobulin five-nucleotide deletion (A2M-2) allele frequency was not significantly higher in the AD group than the control group (0.062 versus 0.101, p > 0.1). The odds ratio for AD in individuals with the A2M-2 allele was 0.582 (95% CI, 0.25 to 1.40). These results do not support the association between A2M-2 and AD in the Chinese population, although the allele frequency of A2M-2 is lower than that found in the Caucasian population. Therefore, A2M-2 might not be a significant risk factor of AD among Taiwan Chinese.

Postoperative short-term sedation with propofol in cardiac surgery

We conducted a randomized double-blind study to assess the safety and effectiveness of short-term sedation with propofol in adult patients immediately after cardiac surgery. Sixty hemodynamically stable adult patients who underwent cardiac surgery were randomly assigned to receive propofol postoperatively or no postoperative sedation. The propofol group (n = 30) received propofol infusion (1 mg.kg-1.hr-1) immediately after they awoke postoperatively. The infusion rates were adjusted to maintain a sedation level (Ramsay score) of 3. Nurses assessed the effectiveness of the sedation according to Ramsay scores; the patients also subjectively evaluated sedation. Postoperative pulmonary oxygenation dysfunction (PaO2/FiO2 < 300 mm Hg) was noted in 10 patients receiving propofol and in eight patients in the control group. The dysfunction was greatly improved after overnight ventilator support, and this improvement was not affected by propofol sedation. The propofol group received an average of 13.6 +/- 5.3 hours of propofol infusion, at an average infusion rate of 0.96 +/- 0.16 mg.kg-1.hr-1. Patients receiving propofol remained well sedated (Ramsay score > or = 2) during 99.3% of the study period, while the control patients remained anxious or agitated (Ramsay score, 1) during 12% of the study period. Patients receiving propofol were successfully extubated 9 +/- 4 minutes after cessation of propofol infusion, without complications. The turnover of intensive care unit beds was not delayed by propofol sedation. Subjective evaluations (scored on an analog scale: 0 = nil, 10 = extreme) revealed that patients receiving propofol felt less pain than those in the control group (2.3 +/- 2.7 vs 4.7 +/- 3.1, p < 0.05), had better sleep quality (7.8 +/- 2.9 vs 5.1 +/- 2.9, p < 0.05), and were more satisfied with the care they received (8.3 +/- 2.2 vs 5.8 +/- 3.9, p < 0.05). These findings suggest that propofol infusion is effective for short-term sedation of cardiac surgery patients postoperatively and that an infusion rate adequate to maintain a Ramsay score of 3 may be ideal. Postoperative sedation should be considered for all cardiac surgery patients, not only those with outward signs of anxiety or agitation.

Expression of Fas ligand in Langerhans' cell histiocytosis: A case report of a boy with multisystem involvement

Previous reports of patients with Langerhans' cell histiocytosis have shown characteristics of osteolytic lesion, visceral involvement and organ dysfunction. We report a 2-year-old boy who was diagnosed as Langerhans' cell histiocytosis with a prominent hepatomegaly. X-Radiogram, computed tomography and magnetic resonance imaging revealed the osteolysis of the right iliac bone, the absence of the left eighth rib as well as the right mandible, and an enhancing mass in the left cerebellum. The data of radiography were highly suggestive of Langerhans' cell lineage. The presence of large CD1a-positive mononuclear cells associated with inflammatory cells in peripheral blood smear and bone marrow aspirate further confirmed the diagnosis. In addition, expressions of S100, CD25, CD68, CD80, CD86, and Fas ligand were identified on these cells by immunocytochemical staining. The results indicate that although these cells are activated Langerhans' cells, progression of the disease and the bone destruction could be mediated by the overt FasL expression of the cells.

Prenatal diagnosis of thoracopelvic dysplasia. A case report

BACKGROUND

Thoracopelvic dysplasia, a variant of asphyxiating thoracic dysplasia (Jeune syndrome), is an uncommon skeletal disorder characterized by a small thorax, pelvic abnormalities and other complex, combined anomalies, including hypomelia, polydactyly and renal anomalies.

CASE

A 32-year-old woman, gravida 1, para 0, was referred at 27 weeks' gestation due to polyhydramnios. Sonography revealed hydramnios, low fetal thoracic circumference (TC) and abdominal circumference (AC) ratio (0.78), skull and skin edema, increased nuchal translucency (7 mm), micrognathia, low-set ears, left cardiac deviation (66 degrees), overriding fingers, and club and rock-buttock feet. Amniocentesis revealed a normal karyotype (46, XY). Asphyxiating thoracic dysplasia was considered. At 40 weeks' gestation, a male infant was delivered vaginally. Besides the prenatal findings, cryptorchidism and high-arched palate were noted. Radiography of the infant revealed a narrow, funnel-shaped thorax and small pelvis with short, flared iliac bones; poorly developed acetabulum; and small, shallow sciatic notch. No dyspnea was observed at five months postpartum.

CONCLUSION

Thoracopelvic dysplasia should be considered when a low TC/AC ratio (< 0.8) is observed. In this case the final diagnosis was made after detailed exclusion of other disorders combined with observation of a small thorax. Prenatal diagnosis of thoracopelvic dysplasia is possible.

Regression of ventricular repolarisation inhomogeneity after aortic bileaflet valve replacement in patients with aortic stenosis

BACKGROUND

Aortic valve replacement relieves mechanical outflow obstruction in patients with aortic stenosis. However, there is limited information on whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity.

OBJECTIVES

To determine whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity in patients with aortic stenosis after bileaflet aortic valve replacement.

METHODS

We studied the changes of electrocardiographic QT or QTc intervals and QT or QTc dispersions of 71 patients with severe aortic stenosis and angiographically insignificant coronary lesions (<50% in diameter) before and after valve replacement (6+/-3 days after operation). Seventy-one healthy control subjects, matched for age and sex, served as control subjects. Twelve-lead electrocardiograms and echocardiographic examinations were measured before and after surgery. The QT interval was corrected for heart rate using the standard Bazett formula. QT dispersion was defined as the difference between maximal and minimal QT interval measurements occurring among any of the 12 leads on a standard electrocardiogram. QTc dispersion was calculated in a manner similar to QT dispersion. No subject had fewer than nine measurable leads.

RESULTS

Left ventricular systolic blood pressure, pressure gradient across aortic valve, left ventricular mass index, and systolic wall stress were significantly reduced after valve replacement compared with before valve replacement. The QT interval significantly decreased from 425+/-38 ms to 398+/-32 ms after replacement (P<0.0001). The QTc dispersion significantly decreased from 62+/-25 ms to 32+/-13 ms after replacement (P<0.0001). The value of QT or QTc dispersion after replacement was similar to that in controls. Univariate analysis revealed that QTc dispersion was significantly only correlated with left ventricular mass index (r=0.236, P=0.05). Multivariate analysis revealed that the best predictor of QTc dispersion was sex and left ventricular mass index (P=0.008 and 0.005, respectively).

CONCLUSIONS

Our study demonstrated a favorable consequence of aortic valve replacement distinct from hemodynamic improvement. Patients with aortic stenosis before valve replacement have abnormal prolonged QT or QTc intervals and increased QT or QTc dispersions. After successful valve replacement left ventricular mass index regressed and QT or QTc intervals and QT or QTc dispersions were normalized. These findings warrant further investigation in a large trial and long-term follow-up for clinical implications.

Effects of substitutions of lysine and aspartic acid for asparagine at beta 108 and of tryptophan for valine at alpha 96 on the structural and functional properties of human normal adult hemoglobin: roles of alpha 1 beta 1 and alpha 1 beta 2 subunit interfaces in the cooperative oxygenation process

Using our Escherichia coli expression system, we have produced five mutant recombinant (r) hemoglobins (Hbs): r Hb (alpha V96 W), r Hb Presbyterian (beta N108K), r Hb Yoshizuka (beta N108D), r Hb (alpha V96W, beta N108K), and r Hb (alpha V96W, beta N108D). These r Hbs allow us to investigate the effect on the structure-function relationship of Hb of replacing beta 108Asn by either a positively charged Lys or a negatively charged Asp as well as the effect of replacing alpha 96Val by a bulky, nonpolar Trp. We have conducted oxygen-binding studies to investigate the effect of several allosteric effectors on the oxygenation properties and the Bohr effects of these r Hbs. The oxygen affinity of these mutants is lower than that of human normal adult hemoglobin (Hb A) under various experimental conditions. The oxygen affinity of r Hb Yoshizuka is insensitive to changes in chloride concentration, whereas the oxygen affinity of r Hb Presbyterian exhibits a pronounced chloride effect. r Hb Presbyterian has the largest Bohr effect, followed by Hb A, r Hb (alpha V96W), and r Hb Yoshizuka. Thus, the amino acid substitution in the central cavity that increases the net positive charge enhances the Bohr effect. Proton nuclear magnetic resonance studies demonstrate that these r Hbs can switch from the R quaternary structure to the T quaternary structure without changing their ligation states upon the addition of an allosteric effector, inositol hexaphosphate, and/or by reducing the temperature. r Hb (alpha V96W, beta N108K), which has the lowest oxygen affinity among the hemoglobins studied, has the greatest tendency to switch to the T quaternary structure. The following conclusions can be derived from our results: First, if we can stabilize the deoxy (T) quaternary structure of a hemoglobin molecule without perturbing its oxy (R) quaternary structure, we will have a hemoglobin with low oxygen affinity and high cooperativity. Second, an alteration of the charge distribution by amino acid substitutions in the alpha 1 beta 1 subunit interface and in the central cavity of the hemoglobin molecule can influence the Bohr effect. Third, an amino acid substitution in the alpha 1 beta 1 subunit interface can affect both the oxygen affinity and cooperativity of the oxygenation process. There is communication between the alpha 1 beta 1 and alpha 1 beta 2 subunit interfaces during the oxygenation process. Fourth, there is considerable cooperativity in the oxygenation process in the T-state of the hemoglobin molecule.

Effect of estrogen on ventricular repolarization in menopausal patients with syndrome X and effects of nicorandil

Syndrome X may exhibit myocardial ischemia and is associated with estrogen deficiency. We sought to assess the possible role of estrogen in modulating the characteristics of ventricular repolarization by measurement of QT interval and QT dispersion in patients with syndrome X. We prospectively used 12-lead electrocardiograms and echocardiograms to study 52 consecutive menopausal patients with syndrome X (group subdivided into subgroup 1a, 32 patients who received nicorandil, an adenosine triphosphate-sensitive potassium ion channel opener; subgroup 1b, 20 patients without dosing nicorandil). For comparisons, a control group consisted of age-matched and echocardiographic left ventricular mass index-matched 20 healthy menopausal women. Baseline QT intervals and QT dispersion were similar between the 2 groups (subgroup 1a and controls). After administration of estrogen, there was significant prolongation of maximal QTc intervals and reduction in QT or QTc dispersion compared with baseline in patients with syndrome X. The changes returned to baseline after nicorandil administration. Control subjects had no changes with administration of estrogen. Thus, estrogen modulates characteristics of ventricular repolarization, which appears to be mediated by blocking adenosine triphosphate-sensitive potassium ion channel. The effects of estrogen on QT intervals may be different between menopausal women with or without syndrome X.

Community-acquired Pseudomonas aeruginosa bacteremia and sepsis in previously healthy infants

Pseudomonas aeruginosa bacteremia, or sepsis, often occurs in hospitals, affecting mainly children with underlying problems. However, it can also appear in communities, and affects infants and children without underlying diseases. We report eight cases of Pseudomonas aeruginosa bacteremia, or sepsis, in previously healthy infants over a three-year period. All patients were less than twelve months old and the majority presented with sepsis, diarrhea, ecthyma gangrenosum, and neutropenia. The infection route may have been the gastrointestinal tract. Concomitant gastrointestinal infections may have played a role in pathogenesis.

Twin vs. singleton pregnancy. Clinical characteristics and latency periods in preterm premature rupture of membranes

OBJECTIVE

To compare the clinical characteristics and latency periods (latencies) of preterm premature rupture of the membranes (PPROM) in twin vs. singleton pregnancy.

STUDY DESIGN

Between January 1986 and December 1996, data on all women with singleton and twin gestations complicated by PPROM were reviewed. Perinatal morbidity, mortality and latencies between singleton and twin pregnancies were compared. A further division according to PPROM at < 30 and > or = 30 weeks' gestation was made in both groups. Their latencies were compared.

RESULTS

A total of 131 singleton and 48 twin pregnancies with PPROM between 20 and 36 weeks' gestation were included in this series. Regardless of the gestational age at PPROM, the mean latencies of singleton and twin pregnancies were statistically similar (4.4 +/- 3.3 vs. 3.4 +/- 2.9 days, nonsignificant). When PPROM occurred at > or = 30 weeks, the latency of twin pregnancies was shorter than that of singleton pregnancies (2.5 +/- 1.9 vs. 3.7 +/- 2.6 days, P < .05). In both groups, the latencies of PPROM at < 30 weeks were longer than that at > or = 30 weeks (singleton, 5.6 +/- 4.0 vs. 3.7 +/- 2.6 days, P < .005; twin, 4.8 +/- 3.5 vs. 2.5 +/- 1.9 days, P < .05). We also observed a higher percentage of deliveries within the initial 48 hours in twin pregnancies: 50% of women delivered within 48 hours after PPROM and 91.7% within 7 days. In contrast, 26.7% and 85.5% of singleton pregnancies with PPROM were delivered within 48 hours and 7 days, respectively. Perinatal and neonatal outcomes in both groups were similar.

CONCLUSION

This investigation provides the basis for patient counseling and management in twin pregnancies with PPROM. In general, singleton and twin pregnancies with PPROM had similar latencies. Latency in PPROM at < 30 was longer than that of PPROM at > or = 30 weeks' gestation in both singleton and twin pregnancies. When PPROM occurred at < 30 weeks' gestation, both groups appeared to have similar latencies. In pregnancies with PPROM at > or = 30 weeks' gestation, latency in twins was shorter than in singleton pregnancies. In twin pregnancies with PPROM after 30 weeks' gestation, prompt steroid administration for fetal lung maturity should be considered.

An R248C mutation of FGFR3 leading to thanatophoric dysplasia type I

Thanatophoric dysplasia (TD) is the most common form of lethal neonatal dwarfism with micromelic shortening of the limbs, macrocephaly, platyspondyly, and reduced thoracic cavity. R248C mutation in the extracellular domain of fibrobast growth factor receptor 3 (FGFR3) was common in TD type I. Two TD type I patients were examined for R248C mutation by use of restriction digestion and direct sequencing. The results showed that both patients carried R248C mutation. Because of the homogeneity of R248C mutation among different ethnic populations, all TD patients should be analysed using this PCR-based method presented in this work.

Prenatal prediction of spinal muscular atrophy in Chinese

We used linkage analysis, non-isotope SSCP (single-strand conformation polymorphism) and PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) for prenatal diagnosis of spinal muscular atrophy (SMA). A total of 26 cases from 20 SMA families (16, type 1 and 4) were evaluated. 5 out of 26 fetuses were affected and, following genetic counselling, the parents decided to terminate the pregnancies. Aborted fetal tissues were examined and the diagnosis was confirmed in each case. The 21 unaffected cases were either normals (12 cases) or carriers (9 cases). These children have been followed for six months to two and a half years. No false-negative or false-positive results on prenatal testing were found. We conclude that prenatal diagnosis of SMA is reliable and accurate.

Measurement of funny current (I(f)) channel mRNA in human atrial tissue: correlation with left atrial filling pressure and atrial fibrillation

INTRODUCTION

The funny current (I(f)) contributes to phase IV spontaneous depolarization in cardiac pacemaker tissue. Enhanced I(f) activity in myocardial tissue may lead to increased automaticity and therefore tachyarrhythmia. We measured the amount of I(f) activity in the messenger ribonucleic acid (mRNA) in human atrial tissue and correlated the mRNA amount to left atrial filling pressure and atrial fibrillation (AF).

METHODS AND RESULTS

A total of 34 patients undergoing open heart surgery were included (15 men and 19 women, aged 55+/-10 years). Atrial tissue was obtained from the right atrial free wall, the right atrial appendage, the left atrial free wall, and the left atrial appendage, respectively. The mRNA amount of the I(f) channel was measured by reverse transcription polymerase chain reaction and was normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase. We found that the I(f) channel mRNA was present at all the atrial sampling sites. A higher left atrial filling pressure, an indicator of congestive heart failure, was associated with a higher I(f) mRNA level (r2 = 0.446, P < 0.01 by linear regression). We also found that the mRNA amount was significantly higher in patients with AF than in patients without AF (1.68+/-0.49 vs 1.27+/-0.43; P < 0.05). Age, sex, right atrial filling pressure, left atrial dimension, and left ventricular ejection fraction had no significant effect on the mRNA level.

CONCLUSION

The mRNA of the I(f) channel is present in the free-wall area and appendage area from both atria. Increased left atrial filling pressure and clinical AF are associated with increased I(f) mRNA level.