A rare nonsense variant of the X-gene in a paediatric patient with severe peripheral pulmonary stenosis

Background

Most cases of peripheral pulmonary stenosis (PPS) associated with William's syndrome are usually very mild or resolve spontaneously. However, we encountered a paediatric case of William's syndrome (WS) with severe PPS. In this case, we investigate whether the patient's genetic background was responsible for the severity of the PPS.

Case presentation

Shortly after birth, the male patient was suspected as WS because of his peculiar facial appearance and PPS. Fluorescence in situ hybridization identified microdeletion in the 7q11.23 region, and he had a confirmed diagnosis of WS. PPS became worsened subsequently, and a cardiac catheterization was performed at the age of 7 years. Due to severe multiple PPS, the right ventricular pressure exceeded the left ventricular pressure. At the age of 12, he had haemoptysis, which required ventilatory management. A pseudoaneurysm of the right pulmonary artery was identified and a right middle lobectomy was performed.

Methods and results

First, we performed multiplex ligation-dependent probe amplification and whole exome sequencing, considering the possibility of homozygous mutations in the region responsible for WS (7q11.23) or a larger deletion of this region in the patient. The deletion was confirmed to be a heterozygous deletion with a typical range for WS. Therefore, we hypothesized that the causative gene of severe PPS may exist separately from the region responsible for WS. After reviewing the result of the whole exome sequencing, we identified a rare nonsense variant of the “X”-gene as the disease-causing gene. The X-gene is involved in the suppression of vascular smooth muscle cell proliferation and the generation of pulmonary arteriolar dilator “Y”. The X-gene has been reported as a disease-causing gene in patients with pulmonary arterial hypertension. Based on these previous reports, we assumed that the X gene variant could be a cause of PPS; therefore, we performed functional analysis. We first introduced a mutant X-gene construct into human pulmonary arterial endothelial cells (hPAECs) and human pulmonary arterial smooth muscle cells and found that the mutant significantly reduced the production of Y compared to the wild-type X-gene. When transfected into hPAECs, the mutant X gene significantly increased cell proliferation compared to the wild-type X-gene. The hPAECs also showed reduced caspase 3/7 activity and reduced apoptosis compared to wild-type X-gene transfected cells. In the patient's own lung pathology specimens, irregular fibrous thickening of the intima of the intrapulmonary arteries was observed, which supported the results of the functional analysis.

Conclusion

Our study showed that an X-gene variant could lead to reduced Y production in the pulmonary arteries, abnormal proliferation of hPAECs, and the development of severe PPS. As Y-replenishing drugs are already in clinical use, the results may lead to the development of medical treatments for severe PPS.

Funding Acknowledgement

Type of funding sources: None.

Advanced pathologic study for definite diagnosis of mitochondrial cardiomyopathy

 

Mitochondrial cardiomyopathy (MCM) is usually recognized as one of the phenotypes of systemic mitochondrial disease. However if there are no cardiac symptoms, it is difficult to make a definite diagnosis because of various cardiovascular phenotypes and no diagnostic criteria in pathological examination. To add myocardial pathology to the diagnostic criteria for mitochondrial respiratory chain disorders, which is the gold standard in the diagnosis of mitochondrial diseases, we performed quantitative analysis of mitochondria using electron microscopy and immunohistopathologic analysis with respiratory chain enzyme antibodies. Ten patients with hypertrophic or restrictive cardiomyopathy who had undergone endomyocardial biopsy were studied. Respiratory chain enzymatic assay and genetic study were performed and four patients were diagnosed with MCM. Using electron microscopy with quantitative analysis, volume density of mitochondria within cardiac muscle cells was significantly increased in the MCM group compared to the non-MCM group (p=0.013). Immunohistopathologic results were compatible with the result of the respiratory chain enzymatic assay. These advanced pathological tests can distinguish MCM from other cardiomyopathies.

Results of immunopathologic study

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Practical Research Project for Rare/Intractable Diseases from the Japan Agency for Medical Research and Development, AMED.

[Present state of countermeasure to AIDS in the world today]

1.

INTRODUCTION

Only about 10 years have passed since HIV was discovered but WHO presumes that there will be 30 to 40 million infected cases by the year 2,000. This then possesses the possibility of more frequent contact with such persons and thus means we must look for how to protect ourselves. I would like to discuss the present state of AIDS, particularly in eastern European countries such as Bulgaria, Hungary, Romania and Russia, based on recent data I have compiled. 2. AIDS-related laws at present in various countries. (1) Comparison of major laws (17 countries) including 1) patient (17 countries) and infected person (13 countries) notification, 2) protection of privacy (9 countries), 3) prohibiting infected person discrimination (3 countries) and 4) other matters including restraint on behavior to spread infection (6 countries). (2) Entry laws from foreign country (10 countries) applicable to patient and infected person for 1) entry (3 countries) and 2) long period of stay (8 countries). 3. Present countermeasures to AIDS. (1) Data for 8 countries including Japan, U.S.A. U.K., France, Germany and three eastern European countries with regard to 1) budgets, 2) examinations, 3) medical care, 4) consultation and guidance and 5) education. I shall also discuss the following 2 countermeasures in Japan. I have proposed to the Diet: 1) Examination to detect HIV-antibodies in donated blood. This measure is present in effect since Nov. 1st, 1986, as a result of my proposal made to the Diet on March 14th, 1986. 2) For person infected by transfusion of the blood products without heat treatment, I proposed that expenses should be defrayed according to the CD4 level at either CD4 < or = 200 or CD4 < or = 500. (2) Present situation in eastern European countries. Common features are as follows: 1) Infected person and patient are quarantined if they request, since they know their condition which was disclosed based on data from past mass screening test under communism. 2) At present infected persons are few in number. 3) This number will rapidly increase with greater active interchange with western countries following elimination of the Berlin Wall. 4) AIDS countermeasures such as blood and blood products examinations are inadequate due to insufficient funds. In Bulgaria, the government has conducted AIDS tests on more than half the population and in Romania, there is the tragic situation. (3) Guidelines for WHO-ILO countermeasures to AIDS at work places. 4. Present situation in research. The development of effective medicines and vaccines is the primary objective of AIDS research. Research programs may be enumerated as follows; 1) In the U.S.A., NIH and CDC are major organizations which lead research around the world. The major objective is synthetic medicine. 2) In U.K., the development of vaccines for monkey and cat is being sought. 3) In China, herb medicine is administrated to patients in Un-nan-sho where AIDS patients are quite numerous. 4) In Japan, a recombinant vaccine is being sought through use of BCG, vaccinia viruses and the like. 5. Topics related to AIDS include 1) informed consent to be treated by a AIDS-infected doctor, 2) suits against doctors who fail to make infected person known infection and 3) government control laws for AIDS in Russia.

Tissue factor in plasma of patients with disseminated intravascular coagulation

Recently it has been shown that tissue factor (TF), an important trigger for initiating blood coagulation, is present in the circulating plasma. In order to assess the clinical implications of TF in plasma, plasma concentration of TF was quantitated in 65 patients with disseminated intravascular coagulation (DIC). The mean concentration of plasma TF was elevated in patients with DIC at presentation as compared with healthy subjects (446 +/- SD 536 pg/ml vs. 138 +/- 51 pg/ml, P < 0.001). Abnormally high levels were found only in 46.2% of the patients, predominantly in patients with non-hematological solid tumors and acute leukemia. Plasma TF did not correlate with hemostatic markers of DIC such as thrombin-antithrombin III complex, prothrombin fragment 1 + 2, plasma-alpha 2-plasmin inhibitor complex, FDP, D-dimer, or fibrinogen. Serial determinations of plasma TF demonstrated that plasma TF changes roughly in parallel with the course of DIC in most patients with elevated TF at presentation of DIC. These findings suggest that plasma TF is potentially valuable for monitoring the progress of DIC in a limited population of patients.

Evaluation of oral anticoagulant therapy by measuring plasma prothrombin fragment 1 + 2

To assess the degree of haemostatic system activation, plasma levels of prothrombin fragment 1 + 2 (F1 + 2), a direct indicator for thrombin generation in vivo, were measured in 49 patients with thrombotic disease undergoing long-term warfarin therapy (Thrombotest values < or = 40%). In these patients, vitamin K dependent coagulation factors (factors II, VII, IX and X) were decreased together with the anticoagulant proteins C and S, but the mean plasma concentration of F1 + 2 was significantly decreased compared with 48 healthy subjects. In warfarin-treated patients, F1 + 2 was positively correlated with the Thrombotest value, factors II, VII, IX and X. When analysed according to the intensity of anticoagulation, patients with Thrombotest values less than 30% showed a significant decrease in F1 + 2, but the mean F1 + 2 level was normal in patients with Thrombotests higher than 30%. These findings indicate that long-term oral anticoagulant therapy suppresses thrombin generation approximately in parallel to the decrease in coagulation factors, and levels of F1 + 2 lower than healthy subjects are observed when Thrombotest values are less than 30%.

Plasma von Willebrand factor proteolysis in patients with chronic myeloproliferative disorders: no possibility of ex vivo degradation by calcium-dependent proteases

Patients with chronic myeloproliferative disorders (CMPD) frequently have abnormalities of plasma von Willebrand factor (vWf) multimers. The pathogenesis of this phenomenon is still unknown. In order to evaluate the possibility of ex vivo degradation of vWf during blood processing, we compared vWf antigen, ristocetin cofactor and the multimeric composition of vWf in plasmas obtained in the presence of trisodium citrate with or without calcium-dependent protease inhibitors (leupeptin, N-ethylmaleimide and Na2EDTA). The subjects included 20 patients with CMPD, 11 with other diseases and 8 normal subjects. In patients with CMPD and normal subjects, the values of vWf antigen, ristocetin cofactor, ristocetin cofactor/vWf antigen ratio and the relative amount of large multimers of vWf did not significantly differ from each other in plasma samples with and without protease inhibitors. In other diseases, especially in a patient with disseminated intravascular coagulation, a somewhat higher amount of large multimers were found in plasma with protease inhibitors than without inhibitors. These findings indicate that the ex vivo proteolysis during blood processing is negligible in patients with CMPD, and that the observed abnormalities in vWf is an in vivo phenomenon.

Plasma levels of protein C and vitamin K-dependent coagulation factors in patients on long-term oral anticoagulant therapy

Plasma levels of protein C (PC) and vitamin K-dependent coagulation factors (factors II, VII, IX and X) were measured in 100 specimens from patients on long-term warfarin therapy. Both activities and antigens of these coagulation factors were decreased, depending on the thrombotest values. Factor II activity/antigen ratio and factor X activity/antigen ratio were correlated well with thrombotest values, indicating that the concentration of inactive molecules (PIVKAs) relative to normal proteins increases with increasing intensity of anticoagulation. Although PC antigen (PC:Ag) was also decreased, the ratios between PC:Ag and vitamin K-dependent coagulation factor antigens remained constant, being independent of the intensity of warfarin therapy. These findings indicate that long-term oral anticoagulant therapy results in the suppression of the synthesis of both vitamin K-dependent coagulation factors and PC, but the production of the coagulant and anticoagulant proteins is well-balanced.

Protein C levels in disseminated intravascular coagulation and thrombotic thrombocytopenic purpura: its correlation with other coagulation parameters

Protein C was measured by means of enzyme-linked immunosorbent assay (ELISA) in plasmas from 58 normal subjects, 39 patients with disseminated intravascular coagulation (DIC) and 5 patients with thrombotic thrombocytopenic purpura (TTP). Protein C levels ranged from 69.7 to 163.6% (95% confidence limits) in normal subjects. In patients with DIC, protein C concentrations were significantly decreased, with a geometric mean value of 42.1%. Protein C concentration was positively correlated with plasma prothrombin, antithrombin III and serum pseudocholinesterase, and was negatively correlated with von Willebrand factor antigen (vWF:Ag) and vWF:Ag/factor VIII ratio. These findings suggest that low protein C concentrations in DIC mean a consumption of protein C probably due to its activation by thrombin and/or impaired liver synthetic function. In patients with TTP, protein C levels were normal with a geometric mean value of 116.7%, indicating that the pathophysiology of TTP is quite different from that of DIC.

[A study on application of the function of maintaining concentration (TAF) for chronic schizophrenia]

The function of maintaining concentration (TAF) is the new method of the evaluation of fatigue that has been devised by Takakuwa. Chronic schizophrenia are observed in everyday affairs, as if they have "fall of work will and lowering of work sufficiency". Reasonable approaches to the evaluation of these state of chronic schizophrenia may be provided by TAF test. The patients who are grasped by TAF test as lowering of their ability are recovered by prescription of the apt dose of an antipsychotics. The interruption or overdose of the medicine leads again to a lowering of TAF. No change of TAF after the interruption of the medicine is considered as the remission. The all 3 cases may be indicated that TAF test has clinical application.

[Studies on the items for diagnosis of the vibration disease. Part 1. Examination of healthy workers using vibratory tools]

1,215 male workers using bush cleaners in Hokkaido were examined by the method based on the notification of the Labor Standard Bureau. The results obtained from clinically normal 548 workers among them were analysed especially on the finger skin temperature, vibratory sense threshold, maximum grip strength. 1) Data of the vibratory sense threshold, maximum grip strength and endurable grip strength showed normal distributions. Data of the finger skin temperature, however, showed a skewed distribution. 2) In parallel with aging, the vibratory sense threshold increased, in other words, lowered in function, and the maximum grip strength lowered. 3) The endurable grip strength measured by the five-time repetition method decreased along with aging. 4) Values of one-tail limit of the finger skin temperature were calculated in all 548 workers, and those of the vibratory sense threshold, maximum grip strength and endurable grip strength were done in each age group. The values were compared with the already proposed criteria and discussed.

[Studies on the change of spontaneous locomotor activities in rats due to forced exercise (author's transl)]

The authors have devised an apparatus for monitoring the spontaneous locomotor activity of rats, with which the patterns of locomotor activity under the condition of light-dark cycle (light period: twelve hours from 6 a.m., dark period: the other half of the day) were analysed. In addition, changes in locomotor activities due to forced exercise (swimming) were recorded. The results obtained were as follows: 1. The patterns of locomotor activities in rats recorded by the monitor showed the same patterns as reported already by other researchers. The authors believe that this new apparatus can be used practically as a locomotor activity monitor. 2. Due to exhaustive exercise by swimming, changes of the ultradian rhythm in rats were observed. 3. By loading of swimming, locomotor activities in rats decreased significantly, especially in the dark period. These results suggest that this newly devised apparatus is useful as a locomotor activity monitor, and that the fatigue in rats caused by physical load can be shown as the change in locomotor activities.

Effect of physical exercise on the activity of GOT isozyme in human plasma

Untrained healthy male volunteers were subjected to the study on the effects of exercise (bicycle ergometer, 920 kpm/min for 30 min) upon GOT isozyme (supernatant GOT, s-GOT and mitochondrial GOT, m-GOT) activities in plasma. Significant increases in the levels of both s-GOT and m-GOT activity were observed after the exercise (p less than 0.001). After 30 min of rest m-GOT activity almost returned to its preexercise value. However, s-GOT activity did not return to its preexercise activity. The changes in the activity of GOT isozyme after physical exercise are discussed.

A study on the toxicity of natural food dyes--toxicity and enzyme inhibition in Paramecium caudatum

The toxicity of 14 commercial natural dyes which are widely used as food additives in Japan was studied on Paramecium caudatum. Laccaic acid and capsanthin were found to be very toxic to Paramecium caudatum. Some of the commercially available carminic acid and crocin were also toxic. The inhibitory effect of natural food dyes on leucine aminopeptidase, acid phosphatase and esterase in vitro was proportional to the toxic effect of the dyes on the survival time of Paramecium caudatum. Analyses of the commercial natural food dyes by high performance liquid chromatography failed to identify the toxic components.

Effect of thyroid hormone on the levels of erythrocyte carbonic anhydrase isozymes and 2,3-diphosphoglycerate in rabbits

Levels of rabbit erythrocyte carbonic anhydrase B and C isozymes were determined in experimental hyperthyroidism using a quantitative immunologic technique. Levels of erythrocyte 2,3-diphosphoglycerate and protein binding iodine were simultaneously determined. Thyroxine and 3,5,3'-triiodothyronine were administered to rabbits orally for 30 days. A significant decrease in carbonic anhydrase B type was observed after 30 days, although no significant change was observed in carbonic anhydrase C type. These findings suggest that the steady state level of carbonic anhydrase B type in red cells is affected by thyroid hormone more readily than that of carbonic anhydrase C type. The level of red cell 2,3-diphosphoglycerate increased markedly after 10 days of treatment, corresponding to the increase of protein binding iodine. The clinical or pathologic significances were discussed in relation to the changes in the levels of these isozymes and 2,3-diphosphglycerate in red cells.

[Work load due to stamping task as a simple repetitive hand work (author's transl)]

An experimental study was carried out on stamping task using no conveyers with short work cycle which was taken as featuring simple repetitive hand work. Each phase of this work was allowed to each subject. Seventeen healthy adults, 8 males and 9 females, were engaged in the 120 minutes, stamping task. They were tested by their function of concentration maintenance (TAF), by flicker frequency and 30 items of subjective symptoms as advocated by the Japan Association of Industrial Health. Quantities of work for each 10 minutes were calculated. The results obtained were as follows: 1) Number of stamped cards by male subjects was more than that by female subjects. 2) Pace of work performance in the female subjects was being kept more in balance with their capacity in comparison with the male subjects. 3) The results of TAF and FF tests showed that the body load in the male subjects were greater than in the female subjects.

Gamma-glutamyltransferase from azo dye induced hepatoma and fetal rat liver. Similarities in their kinetic and immunological properties

Some properties of gamma-glutamyltransferase ((gamma-glutamyl)-peptide: amino-acid gamma-glutamyltransferase EC 2.3.2.2) from azo dye induced hepatoma and fetal rat liver were studied using kinetic and immunological criteria. There was no significant difference between the hepatoma enzyme and fetal rat liver enzyme in some of their catalytic properties. Antisera against the purified hepatoma enzyme also reacted to the fetal rat liver enzyme in the inhibition test and the precipitin reaction. A structural similarity between the hepatoma enzyme and fetal rat liver enzyme was observed and the acquirement of fetal characteristics in hepatoma was discussed.

Estimations of active and inactive carbonic anhydrase isozyme B in human red cells

Human erythrocyte carbonic anhydrase isozyme B was measured by a specific and immunological method. The levels of carbonic anhydrase B were determined in normal subjects, patients with hyperthyroidism, and patients with chronic obstructive lung disease and patients with epilepsy under treatment with acetazolamide, using the rapid assay method of single radial immunodiffusion. The levels of carbonic anhydrase B showed a decrease in hyperthyroidism, and increased in chronic obstructive lung diseases and epilepsies. Closely negative correlations were observed between carbonic anhydrase B and T3 resin sponge uptake or protein bound iodine (PBI) levels in hyperthyroidism. Simultaneously, carbonic anhydrase B-dependent esterase activity (active carbonic anhydrase B enzyme) was determined kinetically using the immunoadsorbent method in the above-mentioned patients. The results were compared with the total enzyme protein (active and inactive carbonic anhydrase B enzyme), estimated by the single radial immunodiffusion technique. In patients treated with acetazolamide, the "true" specific activity of the carbonic anhydrase B (carbonic anhydrase B-dependent esterase activity/total carbonic anhydrase B protein) decreased remarkably. In chronic obstructive lung disease, no remarkable changes were observed. On the other hand the specific activity was elevated in hyperthyroidism to 2 times higher than that of normal subjects. The clinical significance of these active enzymes is discussed.