Profile of cytokine expression in nasopharyngeal carcinomas: a distinct expression of interleukin 1 in tumor and CD4+ T cells

Nasopharyngeal carcinoma (NPC) is an epithelial cancer that is causally associated with Epstein-Barr virus (EBV) infection. NPC tumor biopsies are characterized histopathologically by an abundant infiltration of nonmalignant lymphocytes. We analyzed the expression of various cytokines in NPC tissues to investigate the interaction of the infiltrating lymphocytes and tumor cells. Analysis using reverse transcriptase-PCR revealed the expression of a panel of cytokines in the NPC biopsies: interleukin (IL)-1alpha, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-10, IFN-gamma, tumor necrosis factor-alpha, transforming growth factor-beta, and IL-1 receptor types I and II. Elevated expression of IL-1alpha and IL-1beta was observed in primary tumors and NPC metastases compared to control tissues. Interestingly, this increased expression correlated with the EBV-encoded viral IL-10 transcript. To determine which cells were responsible for producing IL-1, we determined the cellular constituents of NPC biopsies by immunoflow cytometric analysis. On the basis of data from these analyses, the three major specific cell populations, epithelial cells, CD4+ T cells, and CD8+ T cells, were selected from five NPC tumors using specific, antibody-coated paramagnetic beads. Reverse transcriptase-PCR of RNA from these fractionated cells showed that transcripts of IL-1alpha and IL-1beta were present not only in the malignant epithelial cells but also in CD4+ T cells infiltrating the tumor, a finding confirmed by immunohistochemical staining. We hypothesize that the unusual synthesis of IL-1alpha and IL-1beta by EBV-positive epithelial cells as well as by CD4+ T cells might contribute to lymphocyte infiltration and/or tumor growth during NPC development.

Sufficient length of a poly(A) tail for the formation of a potential pseudoknot is required for efficient replication of bamboo mosaic potexvirus RNA

RNAs transcribed from a full-length infectious cDNA clone of the bamboo mosaic potexvirus (strain O) genome, pBaMV-O, were infectious to Nicotiana benthamiana plants. Mutant genomes in which the poly(A) tail is absent or replaced by a 3' tRNA-like structure from turnip yellow mosaic virus RNA failed to amplify detectably in N. benthamiana protoplasts. No amplification was detected in protoplasts inoculated with transcripts containing 4, 7, or 10 adenylate residues at the 3' end, whereas transcript inocula with 15 adenylate residues resulted in coat protein accumulation to a level 26% of that resulting from inoculation with transcripts with 25 adenylate residues (designated as wild type). Coat protein accumulation levels of 69 and 98% relative to wild type were observed after inoculation of protoplasts with transcripts bearing poly(A) tails 18 and 22 nucleotides long, respectively. The presence of a putative 3' pseudoknot structure including at least 13 adenylate residues of the 3'-terminal poly(A) tail was supported by enzymatic and chemical structural analysis. The functional relevance of this putative pseudoknot was tested by mutations that affected basepairing within the pseudoknot. These results support the existence of functional 3' pseudoknot that includes part of the 3' poly(A) tail.

Prenatal diagnosis of dyssegmental dysplasia. A case report

BACKGROUND

Since the first use of sonography, most fetal dwarfism has been detectable prenatally. The correct differentiation of the subtype of dwarfism is difficult at times. Dyssegmental dysplasia is probably an exception to these subtypes because the vertebral disorganization and occipital encephalocele at times permits prenatal diagnosis.

CASE

A 34-year-old woman, gravida 3, para 1, elective abortion 1 for dwarfism, was referred at 27 weeks' gestation for cystic hygroma. Further sonographic findings included: cystic hygroma with massive ascites, micromelia, occipital encephalocele, spinal disorganization and hydramnios. The fetus and both parents appeared to have a normal karyotype. Later the pregnancy was terminated with vaginal delivery. The fetus had micromelia, camptomelia, cystic hygroma, a flat face, short neck, short trunk, narrow thorax with protuberant abdomen, scoliosis and clubfeet.

CONCLUSION

Sonography is effective in prenatal diagnosis of dyssegmental dysplasia. With sonography, diagnosis of dyssegmental dysplasia becomes possible as early as the first trimester.

Influence of perinatal factors on limit of viability in extremely low birth weight infants

This retrospective study investigated the influence of perinatal factors on the limit of viability in extremely low birth weight (ELBW) infants. From January 1997 to May 1998, all infants weighing less than 1000 gm admitted to NICU of China Medical College Hospital were enrolled in this study. Still-born infants and infants with congenital anomaly were excluded. The end outcome was survival of the infants (defined as alive at discharge). Eighty-four infants were included in this study. Their mean gestational age (GA) was 25.8 +/- 1.76 weeks, mean birth weight (BW) was 772 +/- 114 gm, and overall survival rate was 48.8%. The smallest intact survival was a female infant of GA 23 weeks and BW 530 gm. Early neonatal mortality rate (< 7 days) was 26.2% (23/84). The cut off levels, below which mortality significantly increased, were GA < 24 weeks and BW < 700 gm (odds ratio, 6.11, confidence interval, 2.01 to 18.63 for GA; odds ratio, 2.65, confidence interval, 1.09 to 6.39 for BW). The two most significant factors which independently affected neonatal survival were GA < 24 weeks and early neonatal dexamethasone treatment for the prevention of chronic lung disease (odds ratio, 9.24, confidence interval, 2.53 to 33.76 for GA; odds ratio, 35.83, confidence interval, 7.03 to 183 for dexamethasone treatment). We conclude that in order to further reduce neonatal mortality, efforts should be made in the areas of prenatal care and women's health to prevent extreme prematurity and low birth weight infants. In the case of an impending delivery of an ELBW infant, an active plan of management for all gestations > or = 24 weeks seems appropriate. Finally, unless it is proven to be safe, early neonatal dexamethasone treatment for prevention of chronic lung disease should not be routinely used in ELBW infants.

The significance of early subtle coronary arterial lesions on echocardiogram in Kawasaki disease

Intensive echocardiographic studies were undertaken in 37 patients with Kawasaki disease (KD) and 12 febrile controls during the acute stages. Video-tape recordings were read doubly-blinded by 3 pediatric cardiologists at 2 hospitals. Three characteristics of subtle coronary arterial lesions, including contour of lumen, smoothness of endothelium and sono-homogeneity of the surrounding tissue were particularly described. Seven of the 37 KD patients (19%) were found to have coronary arterial aneurysms (CAA) at the end of the convalescent stage. The 3 cardiologists agreed in the diagnosis of the subtle lesions by 72%. More patients with Kawasaki disease were found to have an irregular endothelium than the controls (P < 0.001). KD patients later complicated with CAA were more likely to have had the three characteristics of subtle coronary lesions during the acute stage than the KD patients without aneurysms (P < 0.001). Also, the coronary arterial size measured during the acute stage were found to be positively correlated with their largest dilatation at the convalescent stage (P = 0.0001, r = 0.61). We conclude that early subtle coronary arterial lesions can herald the development of coronary arterial aneurysms.

Kawasaki disease complicated by peripheral gangrene

An 8.5-month-old male infant with Kawasaki disease (KD) received high-dose intravenous immunoglobulin (IVIG) therapy on the fifth day after fever onset. However, multiple peripheral limb ischemias occurred 2 days later. Accordingly, heparin followed by dipyridamole was administered. Aside from a small amputation at the tip of the right middle finger, all other digital ischemias resolved. This presentation demonstrates that early recognition and management of peripheral gangrene in KD may keep its sequela to a minimum.

Different race, different face: minor anomalies in Chinese newborn infants

OBJECTIVE

To define the nature and incidence of minor anomalies in Chinese newborn infants and to evaluate the validity of the hypothesis that infants with three or more minor surface anomalies will also have a major malformation.

METHODS

A total of 3,345 Chinese newborn infants were examined based on a list of 67 items of minor anomalies.

RESULTS

About 44.9% of the newborn infants had at least one minor anomaly that was unrelated to gender, maternal age, or gestational age, but significantly associated with fetal presentation. Breech-presented newborn infants had double the risk of minor anomalies. Simian crease, upward slant and frontal bossing could be considered normal variants for Chinese newborn infants, because the incidence of each was higher than 4%.

CONCLUSIONS

Although some studies have shown that approximately 90% of infants having three or more minor anomalies are associated with a major malformation, we found only a 10.1% predictive value based on this study. Nevertheless, we suggest that infants with three or more minor anomalies be carefully evaluated for the possibility of major malformation in order to provide early management.

Child with velocardiofacial syndrome and del (4)(q34.2): another critical region associated with a velocardiofacial syndrome-like phenotype

We report on a child with congenital heart disease (atrial septal defect, ventricular septal defect, pulmonic stenosis), submucosal cleft palate, hypernasal speech, learning difficulties, and right fifth finger anomaly manifestations, consistent with velocardiofacial syndrome (VCFS); however, cytogenetic analysis demonstrated a small terminal deletion of the segment 4q34.2 to 4qter. Fluorescent in situ hybridization did not identify a deletion of the critical region associated with VCFS. In previously reported 4q deletions with a breakpoint distal to 4q34.2, no cardiac defects or cleft of palate were reported. Our patient has a deletion of 4q34.2 to 4qter and has palate and cardiac involvement and minor learning difficulties, which implies that genes involved in heart and palate development lie distal to 4q34.2, and that the critical region for more severe mental retardation on 4q may reside proximal to 4q34.2. These results suggest that a distal 4q deletion can lead to a phenotype similar to VCFS and emphasizes the importance of searching for other karyotype abnormalities when a VCFS-like phenotype is present and a 22q deletion is not identified.

Cutaneous telangiectasias, sparse hair, and type I membranoproliferative glomerulonephritis

We report the unusual association of normocomplementemic type I membranoproliferative glomerulonephritis in a 10-year-old girl with sparse red hair, absent eyebrows and eyelashes, cutaneous telangiectasias, and an atrial septal defect.

Hepatic abscess due to gastric perforation by ingested fish bone demonstrated by computed tomography

Perforation of the gastrointestinal tract by ingested foreign bodies is rare. Preoperative diagnosis of complications due to foreign bodies in the gastrointestinal tract can rarely be achieved because the conventional radiographic appearance is nonspecific. This report describes a 69-year-old woman who presented with vague clinical manifestations, intermittent abdominal pain, and low-grade fever. Hepatic abscess, secondary to a foreign body penetrating the gastric wall, was diagnosed preoperatively using computed tomography findings. On exploration, the foreign body turned out to be a fish bone. The abscess was confirmed and drained during surgery and a partial gastrectomy was performed. This case illustrates the value of CT in the evaluation of this condition.

The major immunogenic epitopes of Epstein-Barr virus (EBV) nuclear antigen 1 are encoded by sequence domains which vary among nasopharyngeal carcinoma biopsies and EBV-associated cell lines

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) is a protein expressed consistently in EBV-infected cells and EBV-associated malignant tissues. A panel of monoclonal antibodies (MAbs) was generated against the C terminus of EBNA-1 and evaluated for the detection of EBNA-1 in different cell lines. The epitopes recognized were mapped. Since sequence variations of EBNA-1 have been reported in nasopharyngeal carcinoma (NPC) tissues and in infected healthy individuals, the ability of these MAbs to recognize a recombinant protein derived from an NPC biopsy was also analysed. MAb 4H11 appeared to react with EBNA-1 sequences from different sources, whereas MAbs 5C11, 5F12 and 8F6 failed to recognize a recombinant EBNA-1 protein cloned from an NPC patient. Using different recombinant EBNA-1 fragments in an immunoblot format, this study demonstrates that the domain bounded by amino acids 408 and 498 is very immunogenic in mice in that epitopes in this region are recognized by various MAbs. Amino acid sequences of EBNA-1 were also deduced from nucleotide sequences amplified from three Burkitt's lymphoma cell lines, two spontaneous lymphoblastoid cell lines, two NPC biopsies and one NPC hybrid cell line, NPC-KT, and compared to the sequence from B95-8. The amino acid sequence of EBNA-1 in Akata is almost identical to that in an NPC biopsy, except for amino acid 585. The results of this study indicate that the immunogenic epitopes of EBNA-1 are highly variable.

Apoptosis in primary cutaneous amyloidosis

Amyloid deposits in primary cutaneous amyloidosis (PCA) may be initially derived from cytokeratin. possibly after keratinocyte death. However, the mechanism of keratinocyte death remains obscure. To investigate the potential role of apoptosis in the pathogenesis of PCA, a retrospective study was conducted on the skin tissues from 20 Chinese patients with PCA. We used a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) method for detecting the apoptotic cells. Immunohistochemical staining was performed to examine the expression of the B-cell leukemia/lymphoma-2 gene (bcl-2) and Fas. Apoptotic cells were shown in 11 of 20 cases (55%) by TUNEL. Histological sections showed that dyskeratotic cells and vacuolar alteration of the basal cells were more commonly observed in the TUNEL-positive group. In all cases of PCA, epidermal expression of bcl-2 was minimal, while expression of Fas was observed on keratinocytes in the basal to granular layers: however, these findings were not different from those in normal skin. Our results suggest that the keratinocyte destruction in PCA may occur as an initial result of apoptosis, which in turn leads to the amyloid formation.

In vitro elution of vancomycin from biodegradable beads

The current antibiotics delivery system for orthopedic infection treatment uses polymethylmethacrylate (PMMA) beads as a drug release. However the nonbiodegradable nature of the PMMA necessitates a second operation to remove the beads. This article explores the alternative of using biodegradable polymers as antibiotic beads for a long-term drug release. The effect of different processing factors on the release rate of the beads was investigated. To manufacture an antibiotic bead, polylactide-polyglycolide copolymers were mixed with vancomycin. The mixture was compressed and sintered at 55 degrees C to form beads of different sizes. An elution method was employed to characterize the release rate of antibiotic over a 35-day period at 37 degrees C. Biodegradable beads released high concentrations of antibiotic (well above the breakpoint sensitivity concentration) in vitro for the period of time needed to treat bone infection; i.e., 4-6 weeks. A bacterial inhibition test was carried out to determine the relative activity of the released antibiotics. The diameter of the sample inhibition zone ranged from 6.5-10 mm, which is equivalent to 12.5-100% of relative activity. By changing the processing parameters, we were able to control the release rate of the beads. This provides advantages of meeting the specific antibiotics requirement for patients with various surgical infections.

Molecular diagnosis of Apert syndrome in Chinese patients

Apert syndrome is a clinically distinct condition characterized by craniosynostosis and severe syndactyly of the hands and the feet. Apert syndrome results from either of two specific nucleotide substitutions, both C-to-G transversions, in the fibroblast growth factor receptor 2 (FGFR2) gene. To determine if Chinese Apert syndrome patients carry the same mutations, fifteen unrelated Apert syndrome patients and a fetus from a mother with Apert syndrome were studied by the use of restriction analysis and direct sequencing. The results demonstrated that 13 had the Ser252Trp mutation and 2 had the Pro253Arg mutation. Prenatal diagnosis of the fetus was successfully made.

Molecular diagnosis of patients with beta-thalassemia major in central Taiwan by amplified created restriction site analysis

beta-Thalassemia, a hematologic disorder characterized by the deficiency or the absence of beta-globin production, is the most widespread inherited disorder in the world; it is also common in Taiwan. We studied 38 patients in central Taiwan with beta-thalassemia major, using amplified created restriction site analysis for detection. On analysis, six different point mutations were found among 76 chromosomes, of which 32 chromosomes (42.1%) had a C to T substitution at nucleotide 654, 30 (40%) had frameshift codons 41/42 with four nucleotides (TCTT) deletion, 7 (9.2%) had an A to T substitution at codon 17, 3 (3.9%) had frameshift codons 71/72 (insertion of A), 2 (2.6%) had an A to G substitution at position -28, and 2 (2.6%) had frame-shift codons 27/28 (insertion of C). The first two mutations accounted for 62 of the 76 beta-thalassemia mutations in this study. As to mutations in each individual with beta-thalassemia major, the incidence of compound heterozygotes of two different mutations was higher than that of homozygotes of a single mutation (60% vs 40%). Compound heterozygotes of C to T substitution at nucleotide 654 of IVS-2 and frameshift codons 41/42 with four-nucleotide deletion was the most common pattern of beta-thalassemia mutations in each individual (23.7%). Our results were unique compared with those from similar studies performed in southern China. Frequencies of beta-thalassemia mutations found in the current study were assessed and compared with frequencies found in previous studies conducted in northern and southern Taiwan.

Video-assisted endoscopic saphenous vein harvesting for coronary artery bypass grafting

Saphenous vein grafts for coronary artery bypass can be harvested by means of the traditional long incision method, the skin bridge method, or a newly developed endoscopic technique. We applied the endoscopic technique to reduce the length of leg incision and to decrease the frequency of complications. Between September and December 1996, 47 patients underwent coronary artery bypass grafts, 17 of whom volunteered to undergo saphenous vein harvest with the Endopath video-assisted endoscopic saphenous vein harvest (ESVH) system; the other 30 patients underwent the traditional long incision harvest procedure. A total of 22 saphenous veins were harvested from the 17 patients who underwent ESVH. The mean length of the leg wound was 5.8 +/- 1.3 cm and the mean length of the vein harvested was 32.9 +/- 3.4 cm (wound/vein length ratio 17.6%). The wound/vein length ratio of the 30 patients who underwent the traditional open harvest method was 91.5% (30.8 +/- 2.2 cm/34.1 +/- 3.0 cm). ESVH failed and was converted to the conventional method in two cases. The mean time required to harvest the saphenous vein was 72.7 +/- 20.8 minutes in the ESVH group and 45.8 +/- 12.5 minutes in the open surgery group. No wound complications were noted in the ESVH group, except for ecchymosis in three cases. Five patients in the open surgery group had wound discharge (17%). The length of hospital stay was shorter (10.5 +/- 2.6 days vs 15.8 +/- 4.2 days) and fewer analgesics were used in the ESVH group. The rate of cardiac complications was not different between the two groups. Examination of the vein graft under light microscopy also did not reveal any differences. We conclude that the endoscopic technique can provide adequate vein grafts for use in coronary artery bypass grafting and reduce the leg wound complication rate, hospital stay, and use of analgesics.

Opioid receptor independent effects of morphine on membrane currents in single cardiac myocytes

We have examined the effects of morphine, a mu-opioid receptor agonist, on various membrane ionic currents in rat ventricular and human atrial myocytes, using patch-clamp techniques in the whole-cell configuration. Morphine produced a concentration-dependent reduction in peak transient sodium current. When the sodium current (INa) was evoked at 5-s intervals the estimated IC50 for morphine was approximately 30 mumol litre-1. Morphine 10 mumol litre-1 inhibited INa with a 5-mV shift in the potential-dependent inactivation curve to negative potentials and retarded the INa recovery rate from the inactivated state. Use-dependent INa block was not observed when INa was elicited at frequencies varying from 0.2 to 20 Hz. Morphine did not significantly affect the inward calcium current (ICa), transient outward current (Ito) or the inwardly rectifying potassium current (IK1) at a concentration of 30 mumol litre-1. The inhibitory effect of morphine on INa could not be prevented or reversed by treatment with the opioid antagonist naloxone. Therefore, we suggest that morphine can directly inhibit the Na+ inward current and bind to inactivated Na+ channels.

Identification and characterization of the Escherichia coli-expressed RNA-dependent RNA polymerase of bamboo mosaic virus

Bamboo mosaic virus (BaMV), a member of the potexvirus group, infects primarily members of the Bambusoideae. The open reading frame 1 (ORF1) of BaMV encodes a 155-kDa polypeptide that was postulated to be involved in the replication and the formation of cap structure at the 5' end of the viral genome. To characterize the activities associated with the 155-kDa viral protein, it was expressed in Escherichia coli BL21(DE3) cells with thioredoxin, hexahistidine, and S. Tag fused consecutively at its amino terminus, and the fusion protein was purified by metal affinity chromatography. Several RNA fragments, prepared by in vitro transcription, were tested as substrates for the RNA-dependent RNA polymerase (RdRp) activity. Among them, the expressed fusion enzyme was able to generate a 32P-labeled RNA product when 3'-end RNA fragments of the positive strand or negative strand of BaMV were included in the assay mixture. Dot hybridization assay revealed that the reaction products are complementary to their RNA substrates. Taken together, the evidence suggests that the 155-kDa protein encoded by ORF1 of BaMV has an RdRp activity and should be involved in the replication of BaMV. Mutational analyses demonstrate the importance of the GDD motif in the polymerase activity, and deletion studies suggest that the polymerase activity resides in the carboxyl terminus of the 155-kDa viral protein.

Nasopharyngeal swab and PCR for the screening of nasopharyngeal carcinoma in the endemic area: a good supplement to the serologic screening

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer in Taiwan. Early detection is the best way to improve survival for this disease. A prospective study was designed to assess the feasibility of a new screening method for NPC by use of polymerase chain reaction (PCR) based on the close association of NPC and Epstein-Barr virus (EBV).

METHODS

One hundred thirty-three different tissues from nasopharynx, nose, and sinus were investigated by use of PCR to check for the presence of EBV genome. Subsequently, from April 1996 to March 1997, 55 patients were enrolled in a prospective screening study. All patients underwent nasopharyngeal swabs before biopsy. Polymerase chain reaction detection of EBV genome was conducted on swab samples. Anti-EBV viral capsid antigen (VCA) in IgA and IgG class were checked at the same visit.

RESULTS

The EBV genome was present in 91.4% (85/93) of NPC tissues and in 25.0% (10/40) of non-NPC tissues (p < .001, chi2 test). Of the 55 swabs, 49 (89.1%) specimens obtained enough cells for PCR examination. Thirty of these 49 patients were pathologically proved NPC. The presence of EBV were 86.7% (26/30) in NPC group and 42.1% (8/19) in non-NPC group. The sensitivity and specificity were 86.7% and 57.9%, respectively, which were similar to those of serologic method (87.5% and 43.5%) when the cut-off point was set at anti-VCA IgG > or = 160 and IgA > or = 10. Combining both methods elevates the specificity to 84.2%.

CONCLUSIONS

The sensitivity of this PCR screening method is similar to that of the serologic method. Combining both methods can greatly increase the specificity, indicating this new method is a good supplement to the serologic screening of this endemic disease.

Evolution of bamboo mosaic virus in a nonsystemic host results in mutations in the helicase-like domain that cause reduced RNA accumulation

A mutant population of bamboo mosaic potexvirus (BaMV) was isolated after serial passage using Chenopodium quinoa plants. While the wild type inoculum induced indistinct chlorotic lesions, the mutant produced obvious lesions on C. quinoa although RNA accumulation of the mutant in Nicotiana benthamiana protoplasts was significantly reduced compared to wild type. Mutations were identified in the helicase-like domain. One RT-PCR-generated cDNA clone (designated pL1-33) representing the helicase-like region showed four nucleotide mutations encoding three amino acid changes that were shown to result in dramatically decreased viral accumulation. Independent analyses of the effects of these substitutions showed that nucleotide changes at position 1722 resulting in a leucine to proline switch and position 2129 resulting in a histidine to tyrosine switch had the greatest effect on viral accumulation. Combination of these two mutations resulted in a undetectable viral accumulation. We have identified that amino acids within the helicase domain but outside the universally conserved helicase-like motifs that play an important role in viral amplification.

Harlequin ichthyosis: report of one case

Harlequin ichthyosis, or harlequin fetus, is a relatively rare, severe form of congenital ichthyosis. Although the clinical features have been well described, very little is known about the pathogenesis, clinical course, appropriate treatment and prognosis of harlequin ichthyosis because most of these babies with harlequin ichthyosis die within a few weeks of life. We herein report a case of harlequin ichthyosis, which we believe is the first such case in Taiwan.

Association of increased QT dispersion with coronary atherosclerosis in patients with aortic stenosis

To evaluate correlates between electrocardiographic QT dispersion and coronary atherosclerosis in patients with aortic stenosis before aortic valve replacement, 39 consecutive patients >40 years old with symptomatic aortic stenosis and coronary diameter narrowing > or =50% measured by digital angiographic study were included. An additional matched group with insignificant coronary lesions (<50%) consisted of 39 patients for comparisons. Matching by age, sex heart rate and incidence of chest pain resulted in two comparable groups with identical baseline characteristics. Preoperative transthoracic echocardiography and electrocardiograms were performed in all subjects. 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. No subject had fewer than nine measurable leads. There were no significant differences of risk factors of coronary artery disease between the two groups. From a conditional multivariate logistic regression analysis, independent predictors of development of coronary artery disease in aortic stenosis were only QTc dispersion (odds ratio= 1.255, P=0.01). A wide QTc dispersion > or =70 ins) correlated with the presence of angiographically significant coronary artery disease with a sensitivity and specificity of 72% and 79%. The positive accuracy of having significant coronary artery disease in the presence of QTc dispersion > or =70 ms was 78%. The negative predictive value was 74%. In conclusion, electrocardiographic QTc dispersion may provide important clinical information. A wide QTc dispersion in patients with aortic stenosis is associated with a high incidence of coronary artery disease. These findings warrant further investigation in a large trial.

Primary hyperparathyroidism in pregnancy--report of 3 cases

Three cases of primary hyperparathyroidism in pregnancy are described. Patient 1 developed left thigh pain and lower abdominal pain at 34 weeks' gestation. Patient 2 had right flank pain and lower abdominal pain at 32 weeks' gestation. Both patients accepted medical therapy initially, which resulted in poor control of hypercalcemia. Patient 1 delayed her parathyroidectomy until the postpartum period; she had maternal hypercalcemia and neonatal hypocalcemia. Patient 2 accepted parathyroidectomy at 32 weeks' gestation with an uneventful outcome for both mother and baby. Patient 3 was asymptomatic; her hyperparathyroidism was diagnosed postpartum after neonatal hypocalcemia and agreed to parathyroidectomy. All 3 patients had a parathyroid adenoma.

Electrophysiological mechanisms for the antiarrhythmic activities of naloxone on cardiac tissues

It has been reported that naloxone, an opioid antagonist, has antiarrhythmic activity in vivo. In Langendorff perfused rat hearts, we found that ischemia-reperfusion-induced ventricular tachyarrhythmia reverted to normal sinus rhythm after the treatment with naloxone (3 approximately 10 microM). The method of voltage and current clamp were used to study the underlying mechanism of its antiarrhythmic activity on isolated cardiac myocytes. In isolated rat ventricular and in guinea-pig and human atrial myocytes, naloxone prolonged the action potential duration reversibly. In rat ventricular myocytes, naloxone (1 approximately 30 microM) inhibited sodium current (I(Na)), transient outward potassium current (I(to)), and calcium current (I(Ca)). On the contrary, the addition of naloxone significantly increased inward rectifier potassium current (I(K1)). For the effect on I(Na), naloxone did not shift the inactivation curve of I(Na) but retarded the I(Na) recovery rate from inactivation state. Naloxone suppressed I(to) with a significant left-shift of the inactivation curve, however, the time course of I(to) recovery from inactivation was not affected. In guinea pig atrial myocytes, naloxone (10 microM) decreased the delayed rectifier K+ current (IK). These results show that naloxone exert various extent of inhibition on I(Na), I(to), IK and I(Ca). The prolongation of cardiac action potential is related to the inhibition of I(to) and IK. The antiarrhythmic activity of naloxone is more closely related to the inhibition of Na+ and K+ currents rather than the blockade of myocardial opioid receptors.