Clinical and familial study of arrhythmogenic right ventricular cardiomyopathy

Objective　To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods　Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results　All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion　Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle.     

Microphthalmia with linear skin defects (MLS) syndrome evaluated by prenatal karyotyping, FISH and array comparative genomic hybridization

OBJECTIVE: To explore the utility of comparative genomic hybridization to BAC arrays (array CGH) for prenatal diagnosis of microphthalmia and linear skin defects syndrome. METHODS: We used karyotype analysis, FISH and array CGH to investigate an X;Y translocation. Replication studies were done on cultured amniocytes and lymphoblasts. RESULTS: We describe a severe case of MLS syndrome that presented prenatally with multiple anomalies including cystic hygroma, microphthalmia, intrauterine growth restriction and a complex congenital heart defect. Cytogenetic analysis of amniocytes revealed an unbalanced de novo translocation between chromosomes X and Y [karyotype 46,X,der(X)t(X;Y)(p22.3;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2 (Tuple1 x 2)]. MLS diagnosis was made at birth and the prenatal karyotype was confirmed. Replication studies showed the derivative X chromosome was the inactive X. Array CGH confirmed the X and Y imbalances seen in the karyotype and also showed twelve BACs in the MLS region were deleted as a result of the translocation. FISH with BAC clones verified the array findings and placed the X breakpoint in Xp22.2, resulting in the amended karyotype, 46,X,der(X)t(X;Y)(p22.2;q11.2).ish der(X)(DXZ1+,DMD+,KAL-,STS-,SRY-),22q11.2(Tuple1 x 2) arr cgh Xp22.33p22.2(LLNOYCO3M15D10 -->GS1-590J6)x 1,Yq11.222q23(RP11-20H21-->RP11-79J10)x 1. CONCLUSION: The sensitivity of array CGH was valuable in detecting monosomy of the MLS critical region. Array CGH should be considered for the prenatal diagnosis of this syndrome.     

Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos

In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture environment differs from in-vivo conditions in that the oxygen concentration is higher, and in such conditions the mouse embryos show a higher concentration of reactive oxygen species (ROS) in simple culture media. ROS are believed to cause damage to cell membranes and DNA fragmentation in somatic cells. This study was conducted to ascertain the level of H2O2 concentration within embryos and the morphological features of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31 fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was obtained from the IVF-embryo transfer programme. The relative intensity of H2O2 concentrations within embryos was measured using 2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence imaging and DNA fragmentation was observed with transmission electron microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/- SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed only in fragmented embryos, and was absent in non-fragmented embryos. Electron microscopic findings confirmed apoptotic bodies and cytoplasmic condensation in the fragmented blastomeres. We conclude that there is a direct relationship between increased H2O2 concentration and apoptosis, and that further studies should be undertaken to confirm these findings.      

Cloning of cDNA coding for connective tissue activating peptide III from a human platelet-derived lambda gt11 expression library

We report here the cloning of the cDNA coding for platelet connective tissue-activating peptide-III (CTAP-III) from a lambda gt11 expression library prepared using messenger RNA (mRNA) isolated from human platelets. The open reading frame of the clone coded for a protein with 128 amino acid residues. Since the precursor of CTAP-III, platelet basic protein (PBP is 94 amino acids long, the 5'-translated region of the cDNA codes for a leader sequence 34 amino acids long. This leader sequence, like the sequence of mature CTAP-III, shows significant homology to the sequence of platelet factor 4 (PF4), the only other platelet specific alpha-granule protein cloned until now, from a human erythroleukemic (HEL) cell line-derived cDNA library. These leader sequences are probably critical for targeting such proteins to the alpha-granule. Northern blot hybridization with platelet and megakaryocyte mRNA shows a single species mRNA of approximately 0.8 kb, suggesting that the corresponding cDNA is full length. The cloning of platelet specific CTAP-III provides additional evidence for the platelet specificity of the cDNA library used.     

Comparison of three methods for the estimation of total nitrogen losses in hospitalized patients

Since the measurement of total nitrogen output (TNO) is not routinely determined in the clinical setting, its level is frequently estimated using formulas based on the urinary urea nitrogen excretion (UUN). We measured TNO in 124 surgical patients over 990 days (TNO, 19.22 +/- 8.72 g N/day; total urinary nitrogen (TUN) 18.17 +/- 8.70 g N/day; UUN, 15.17 +/- 7.70 g N/day; mean gastrointestinal nitrogen (MGIN) 0.68 +/- 0.49 g N/day; integumental nitrogen (ITGN), 0.34 +/- 0.08 g N/day) and compared the results with the daily estimations using three different formulas: formula A, UUN + 4; formula B, UUN x 1.20 + 1.05, where 1.20 is the reciprocal of the mean ratio UUN/TUN and 1.05 the mean extraurinary nitrogen losses; and formula C, UUN x 1.0986 + 2.55, derived from the regression analysis of UUN vs TNO. TNO estimated by these formulas were 19.17 +/- 7.70, 19.26 +/- 9.24, and 19.22 +/- 8.70 g N/day, respectively. The regression analyses of the estimated TNO from the three formulas versus the measured TNO indicated that formulas A, B and C were equally accurate in estimating TNO over the entire range of UUN. However, when only values of UUN greater than or equal to 30 g N were considered, a modified formula A (UUN + 6) was the best predictor of TNO. Daily audits of the differences between the estimated and measured TNO showed comparable results for the three formulas. In 28.4 to 31.1% of the observed days the differences were higher than +/- 2 g N/day, an error which is not acceptable when estimating the protein requirements in many clinical conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ultrastructural findings in spongy degeneration of white matter in silver foxes (Vulpes vulpes)

Summary Spongy degeneration of white matter in silver foxes is a naturally occurring, hereditary disorder. We report ultrastructural findings in the upper cervical cord of five perfusion-fixed foxes that were examined between 5 weeks and 2 1/4 years after the onset of clinical signs. Large cytoplasmic vacuoles in oligodendrocytes were present in the foxes examined 5, 12 and 20 weeks after the onset. Other early features of the disease were severe vacuolation of myelin sheaths, demyelination, expansion of extracellular spaces and hypertrophy of astrocytes. Evidence of partial demyelination as well as demyelination of entire internodes was found. In the later stages of the disease, the vacuolation was largely resolved but a marked astrogliosis persisted and numerous remyelinated axons were present in the gliotic areas. Vacuolation of oligodendrocytes and partial demyelination has not previously been seen together in a single disease process. The relationship between oligodendrocyte vacuolation, myelin sheath vacuolation and demyelination is discussed. It is concluded that the present condition is due to a primary damage to oligodendrocytes; however, the underlying biochemical lesion is not known.A part of this study was performed while G. Hagen had a period of study at the University of Cambridge (Agricultural Research Council of Norway (NLVF), grant No. 555.027)