Molecular diagnosis of mitochondrial respiratory chain disorders in Japan: focusing on mitochondrial DNA depletion syndrome

BACKGROUND

Although mitochondrial respiratory chain disorders (MRCD) are one of the most common congenital metabolic diseases, there is no cumulative data on enzymatic diagnosis and clinical manifestation for MRCD in Japan and Asia.

METHODS

We evaluated 675 Japanese patients having profound lactic acidemia, or patients having symptoms or signs of multiple-organ origin simultaneously without lactic acidemia on respiratory chain enzyme activity assay and blue native polyacrylamide gel electrophoresis. Quantitative polymerase chain reaction was used to diagnose mitochondrial DNA depletion syndrome (MTDPS). Mutation analysis of several genes responsible for MTDPS was also performed.

RESULTS

A total of 232 patients were diagnosed with a probable or definite MRCD. MRCD are common, afflicting one in every several thousand people in Japan. More than one in 10 of the patients diagnosed lacked lactic acidemia. A subsequent analysis of the causative genes of MTDPS identified novel mutations in six of the patients. A 335 bp deletion in deoxyguanosine kinase (DGUOK; g.11692_12026del335 (p.A48fsX90)) was noted in two unrelated families, and may therefore be a common mutation in Japanese people. The proportion of all patients with MTDPS, and particularly those with recessive DNA polymerase γ (POLG) mutations, appears to be lower in Japan than in other studies. This is most likely due to the relatively high prevalence of ancient European POLG mutations in Caucasian populations. No other significant differences were identified in a comparison of the enzymatic diagnoses, disease classifications or prognoses in Japanese and Caucasian patients with MRCD.

CONCLUSION

MTDPS and other MRCD are common, but serious, diseases that occur across all races.

[Diagnostic accuracy of carotid ultrasonography in screening for coronary artery disease]

OBJECTIVES

This study investigated the diagnostic accuracy of carotid ultrasonography in screening for significant coronary artery disease (% diameter stenosis > or = 75%).

METHODS

Five hundred sixty patients (342 males, 218 females, mean age 66.4 years) underwent both coronary angiography and carotid ultrasonography. Gensini's coronary score was calculated as a quantitative parameter of coronary atherosclerosis. The most hypertrophic intimal-medial complex thickness (IMT) of the bilateral common carotid arteries (distal and proximal to the echo probe in each artery) was measured within 2 or 3 cm from the carotid bifurcation. The mean IMT (mean of these 4 sites), the maximum IMT (maximum of these 4 sites), and number of plaques (localized hypertrophy of IMT > or = 1.1 mm) were calculated as a quantitative parameter of carotid atherosclerosis.

RESULTS

The screening parameters were determined as 0.85 mm mean IMT, 1.1 mm maximum IMT, and at least 2 sites of plaque. The sensitivity, specificity and accuracy rate for the detection of coronary artery disease were 57.3%, 61.6% and 59.6% for mean IMT, 43.5%, 71.1% and 58.6% for maximum IMT, and 60.8%, 70.5% and 66.1% for number of plaques. Furthermore, the overall results (except maximum IMT) were 73.3%, 49.2% and 60.2%.

CONCLUSIONS

These results suggest that carotid ultrasonography is useful as a non-invasive and easy screening method for coronary artery disease. Furthermore, carotid ultrasonography will allow routine observations to follow the progression of coronary atherosclerosis.

Long-term effects of LDL apheresis on carotid arterial atherosclerosis in familial hypercholesterolaemic patients

OBJECTIVES

To assess the long-term effect of LDL apheresis on carotid arterial atherosclerosis in severe familial hypercholesterolaemic (FH) patients.

DESIGN

Changes in existing plaque, new plaque formation and annual progression rate of carotid early plaque were evaluated by B-mode ultrasonography.

SUBJECTS

LDL apheresis group: two homozygous FH and nine heterozygous FH patients received a combination of LDL apheresis and cholesterol-lowering drug therapy for a mean of 7.8 years.

CONTROL GROUP

10 heterozygous FH patients were maintained by medication only for a mean of 5.5 years.

RESULTS

As a result of LDL apheresis treatment, LDL cholesterol levels reduced from 16.0+/-3.60 to 6.43+/-0.07 mmol L(-1) in homozygous FH patients and from 11.5+/-2.46 to 4.32+/-1.2 mmol L(-1) in heterozygous FH patients. During the long-term treatment period, the existing plaque tended to progress and new plaque formation in carotid arteries was also observed in both groups. The annual progression rate of mean maximum intima-media thickness in the common carotid artery was a mean of -0.0023+/-0.0246 mm year(-1) in heterozygous FH patients in the LDL apheresis group, suggesting regression. This was significantly lower when compared with the control group, which had a mean of 0.0251+/-0.0265 mm year(-1) CONCLUSION: The results suggest that the long-term treatment with combined LDL apheresis and drugs may delay the progression of the atherosclerotic process and prompt the stabilization of atheromatous plaque in severe FH patients.

Synovitis in rheumatoid arthritis: scoring of characteristic histopathological features

Synovial tissue specimens obtained from the knee joints of 40 patients with rheumatoid arthritis (RA) and from 22 patients with osteoarthritis (OA) were examined histologically. The histopathological features of RA synovitis and OA synovitis were then compared. Seven criteria items of histopathological features characteristic to RA synovitis were given a score of 1-3 points each in order to evaluate the histological severity of the seven items. Their total scores were then calculated. A comparison of the total RA synovitis score and the total OA synovitis score revealed that RA synovitis showed more than 11 points (maximum 20 points), while OA synovitis showed less than 10 points in all but two cases. Furthermore, the total scores of RA synovitis were then determined in the same manner for other joints, where it was confirmed that five other joints had scores of more than 11 points as well; that is, the intercarpal, wrist, elbow, ankle and hip joints in 52 patients with RA. From these results, it was concluded that in the histological examination of biopsied synovial tissue of RA, if the total score for synovitis is more than 11 points (maximum 20 points), an histological diagnosis of RA synovitis can be confirmed.

Experimental granulomatous vasculitis induced by sensitization with Ascaris suum antigen in mice

Experimental sensitization by repeated intramuscular injection of Ascaris suum antigen (Ag-As) supplemented with Freund's incomplete and complete adjuvants was carried out in 50 BALB/c CrSl c male mice (sensitized group) for 24 weeks, and the results were compared with those in a control group of 25 mice. At the injection sites of the sensitized group, granulomatous angiitis with eosinophil infiltration was observed in all mice, and fibrinoid angiitis in only four. By light and electron microscopic examinations pulmonary granulomatous vasculitis with a few eosinophils was observed at a high frequency (80%) after 12 experimental weeks. Immunohistochemical examination revealed pulmonary vascular and perivascular infiltration of L3/T4 (CD4) positive cells, B cells, IgG and C3 positive cells in addition to activated macrophages, Thy-1 T cells, IgE positive cells, and IgM positive cells after 12 experimental weeks. There were significant increases in the eosinophil cell count of the peripheral blood, the hemagglutination titers of the sheep erythrocytes, IgE and IgM antibodies to Ag-As by ELISA and Western blotting after 8 experimental weeks. After 12 experimental weeks the IgG antibody to the Ag-As was low, but it increased significantly, and the sera showed multiple precipitation lines to the Ag-As by the Ouchterlony method. In conclusion, the pulmonary granulomatous vasculitis in this study is considered to consist of allergic reactions of type IV and probably type III based on type I.

[Quadricuspid aortic valve: a case report and the review of the literature]

We report a case of rare congenital anomaly of quadricuspid aortic valve and coexisting right coronary displacement. A 70-year-old man was admitted to our hospital for heart murmur and ECG abnormality. The trans-esophageal echocardiography and aortography showed moderate aortic stenosis and regurgitation. At the operation, a quadricuspid aortic valve with three equal cusps and one smaller cusp that showed marked calcification and displacement of right coronary orifice were noted. Successful aortic valve replacement and coronary artery bypass grafting were performed and postoperative course was uneventful.

[Survival of bacteria, and release of the endotoxin from the bacterial cells in the dialysates]

Survival of bacteria and release of the endotoxin from the bacteria with and without ultraviolet irradiation in three kinds of dialysate were investigated. The results obtained are as follows: (1) No growth of S. aureus, E. coli, P. aeruginosa, Aspergillus and C. albicans in the saturated dialysates tested were observed. (2) All of the bacterial cells tested here is gradually, and naturally spontaneously inactivated in all the dialysates. (3) Among the dialysates tested, the saturated dialysate, AF-2, is the most effective for inactivating P. aeruginosa ATCC, but the effect depends upon the isolates of P. aeruginosa. (4) The inactivating effect was somewhat decreased when the saturated AF-2 solution was diluted, but the killing effect was still maintained. (5) The bacterial cells are constantly and significantly inactivated by UV irradiation, especially by the direct irradiation. The indirect irradiation, i.e., through glass, has remarkably less effective than the direct one. However, a tendency of the decrease of bacterial cells by the indirect irradiation is maintained with the killing effect of the dialysated, especially in the case of AF-2 solution. (6) No significant increase of endotoxin was observed, even when the bacterial cells were killed by UV irradiation. Therefore, it is recommended to use UV irradiation for inactivating the bacteria. From the results obtained here, it is indicated that there is no possibility of the growth of naturally contaminated bacteria in the dialysates, and is an effectiveness of the use of UV irradiation for inactivating the bacteria cells, in terms of release of the endotoxin from the dead cells.

Reversibility of the inhibitory effect of rhodamine B on the proliferation of cultured human lip fibroblasts

To investigate the reversibility of rhodamine B inhibition of cell proliferation, human lip fibroblast KD cells were cultured for 3 days in the presence of 25 or 50 micrograms/ml of the dye and the effect of removal of the dye from the culture medium on cell histology and on incorporation of [3H]thymidine into the acid-insoluble fraction of the cell layer was investigated. Removal of rhodamine B on the last 1 or 2 days resulted in an increase in cell number, and incorporation of [3H]thymidine was also restored after removal of the dye; [3H]thymidine incorporation by the cells treated with the dye for only the 1st day was the same as that by the control cells cultured without the dye. In conclusion, it was shown that the decrease in KD cell proliferation caused by rhodamine B can be reversed by removal of the dye.

Rat CINC, a member of the interleukin-8 family, is a neutrophil-specific chemoattractant in vivo

Rat cytokine-induced neutrophil chemoattractant (CINC) is a member of the IL-8 family and its human counterpart is MGSA/gro. Rat neutrophil responses in vitro to rat CINC, human IL-8, and human MGSA/gro were studied. CINC concentrations as low as 1 nM induced apparent chemotaxis of rat neutrophils, but human IL-8 and MGSA/gro required concentrations one or two orders higher than that of CINC to attract neutrophils. These data indicate that human IL-8 and MGSA/gro cannot sufficiently substitute for rat counterparts such as CINC in rats. Therefore, the effect of rat CINC on rats was studied. Intradermally injected 10(-10)-10(-7) M CINC dose-dependently caused infiltration of neutrophils. Significant migration of neutrophils appeared by 30 min, and maximum infiltration was observed around 1-2 hr after the injection. CINC induced quick and transient neutrophil accumulation without lymphocyte and monocyte migration or edema formation. CINC, a member of the IL-8 family but a counterpart of human MGSA/gro-related proteins, is a specific neutrophil chemoattractant and can be distinguished from IL-8, which is a chemotactic factor for lymphocytes and neutrophils.

Inhibitory effect of rhodamine B on the proliferation of human lip fibroblasts in culture

The effect of the cosmetic dye rhodamine B on the proliferation of human lip fibroblasts (KD cells) was investigated in a culture system. Rhodamine B at 25 micrograms/ml and above significantly decreased the number of the cells after a 72 h culture. A time course study revealed that 50 micrograms/ml of rhodamine B-induced decrease in the cell number occurred after 48 h and longer, suggesting that the dye inhibited cell proliferation without a decrease in cell attachment. The detachment of [3H]thymidine-labeled cells from the monolayer was unaffected by rhodamine B at 100 micrograms/ml and below. The incorporation of [3H]thymidine and [14C]leucine into the acid-insoluble fraction of the cell layer was significantly inhibited by 50 micrograms/ml rhodamine B treatment. Histologically, the damage of KD cells was not marked, however, a degenerative change of nuclei and an irregular shape of the cells as well as a decrease in the cell number were caused by 50 micrograms/ml rhodamine B. Rhodamine 6G caused a severe damage of the cells, and rhodamine B significantly decreased the cell number; rhodamine 123 had no significant effect; rhodamine 116 significantly increased the cell number. Furthermore, rhodamine B decreased the number of both vascular endothelial cells from bovine aorta and vascular smooth muscle cells from murine aorta after a 72 h culture. It is concluded that rhodamine B inhibits the proliferation of human lip fibroblasts. This rhodamine B effect may be a warning sign for the dye toxicity.

A suitable culture medium for ossification of embryonic chick femur in organ culture

To establish a culture medium which allows ossification in organ culture, 9-day-old embryonic chick femurs were cultured in variously supplemented BGJb-HW2 media. Changes of Ca and Pi concentrations in the BGJb-HW2 medium or the 10% addition of chick embryo extract (CEE) did not induce ossification. Furthermore, combinations of the 10% CEE with a high Ca x Pi product or with 5 mM beta-glycerophosphate (beta-GP) or with 10% horse serum plus a high Ca x Pi product often caused pathological abnormalities in the periosteum. On the other hand, BGJb-HW2 medium supplemented with 5 mM beta-GP induced development of ossification. The Ca content of femurs and the diaphysial hydroxyproline content were markedly increased. Histological observation showed a formation of a thick and active periosteum, numerous osteoblastic cells, a sufficient amount of osteoid tissue and well developed calcified trabeculae without any pathological changes. Thus, the organ culture system using this medium was considered to be an appropriate one for studies on osteogenesis in vitro.

Role of zinc in protection against cadmium-induced toxicity in formation of embryonic chick bone in tissue culture

To clarify a possible mechanism of zinc (Zn)-induced tolerance to cadmium (Cd) toxicity on bone formation, femurs from 9-day-old chick embryos were cultured for 6 days by the roller-tube method in the presence of Cd (2, 4 or 9 microM) and/or Zn (60 microM). Zn prevented a decrease in bone growth caused by Cd at 4 and 9 microM. An increase in calcium (Ca) content of diaphysis was inhibited by Zn in both the presence and absence of Cd. Histologically, Zn protected a Cd-induced degenerative change of mesenchymal cells in the periosteum and that of osteoblasts around the trabecula at each Cd level. At 60 microM Zn, Cd accumulated less in the bone at 2 microM but more at 9 microM. From these results, it was concluded that Zn prevented Cd-induced toxicity in the process of ossification except calcification in a culture system by two different mechanisms, i.e. a decreasing Cd accumulation at a low level of Cd and probably an induction of metallothionein (MT)-like protein at a high level of Cd.

Quantitative study on phagocytosis of human tonsillar adherent cells by the flow cytometric and immunocytochemical methods

An in vitro phagocytosis assay of adherent cells of 12 palatine tonsils (7 children's and 5 adults' cases with persistent angina) was performed by use of flow cytometry (FCM), using fluorescent latex particles (FLP). The mean value of the percentages of phagocytic cells in the children's group (81.4%) was higher than that in the adults' group (64.0%). In addition, separate immunocytochemical stainings with each antibody--Anti-Leu-M5, OKDR, OKT6, S-100, and lysozyme--were made on smear preparations of a child's and an adult's tonsillar adherent cells after incubation with FLP. By use of the light microscope, the percentages of phagocytic cells in relation to positive cells for each antibody were calculated. The lysozyme positive cell proved to have the highest percentage of phagocytic cells. Then, the average number of phagocytized FLP in one positive cell for each antibody were calculated. With regard to the lysozyme positive cell, this cell proved to have the highest average number of FLP.

Multinucleated giant cells in the palatine tonsil of three patients with pustulosis palmaris et plantaris

In a histopathological analysis of the palatine tonsils resected in 70 patients (28 adults and 42 children) with persistent angina, several Langhans'-type giant cells without epithelioid granuloma were detected in the serial specimens of all tonsils from 3 adult patients with pustulosis palmaris et plantaris. By contrast, in the tonsils of the other 67 patients, without pustulosis palmaris et plantaris, only a few atypical multinucleated giant cells including those of foreign body type were found, in the serial specimen of 4 cases. On the basis of these results, the appearance of Langhans'-type giant cells in the tonsil should be noted in persistent angina with pustulosis palmaris et plantaris.