Thiopalmitic acid-mediated Fe(III)-nitrilotriacetate reduction and lipid peroxidation

The mechanism of the antioxidant action of thiopalmitic acid (SH-Pal) was examined in an in vitro system measuring ferric (Fe(III)-nitrilotriacetate (NTA)- and Fe(III)-NTA/ascorbic acid (AsA)-induced lipid peroxidation of rat liver phospholipid liposomes and microsomes. The extent of lipid peroxidation was determined by measuring thiobarbituric acid reactive substances (TBARS). SH-Pal and glutathione (GSH) scarcely stimulated the Fe(III)-NTA-induced lipid peroxidation in contrast with the mode of action, being similar to those produced by reducing-agent antioxidants such as cysteine and AsA. SH-Pal reduced iron similar to the action produced by AsA and cysteine, but not that of GSH under the same conditions. Also, the reduction of iron by SH-Pal did not exhibit a pH dependency. Similarly, microsomal lipid peroxidation and oxygen consumption induced by Fe(III)-NTA/AsA were inhibited by the addition of SH-Pal in a time and dose dependent fashion, but GSH and cysteine exhibited a lower protective action. Time course studies on TBARS formation and oxygen consumption indicated the ability of SH-Pal to inhibit initiation and propagation reactions. Moreover, the microsomal lipid peroxidation induced by Cumene hydroperoxide (CumOOH) was progressively suppressed by the addition of increasing amounts of SH-Pal. These findings suggest that the antioxidant action of SH-Pal is partly due to complete reduction of iron at a faster rate and inhibition of oxygen consumption during the progress of the peroxidation. Further, SH-Pal has a protective action against free radical damage by hydroperoxy radical.

Modulation of promoter occupancy by cooperative DNA binding and activation-domain function is a major determinant of transcriptional regulation by activators in vivo

Binding of transcriptional activators to a promoter is a prerequisite process in transcriptional activation. It is well established that the efficiency of activator binding to a promoter is determined by the affinity of direct interactions between the DNA-binding domain of an activator and its specific target sequences. However, I describe here that activator binding to a promoter is augmented in vivo by the effects of two other determinants that have not been generally appreciated: (i) the number of activator binding sites present in a promoter and (ii) the potency of activation domains of activators. Multiple sites within a promoter can cooperatively recruit cognate factors regardless of whether they contain an effective activation domain. This cooperativity can result in the synergistic activation of transcription. The second effect is the enhancement of activator binding to a promoter by the presence of activation domains. In this case, activation domains are not simply tethered to the promoter by the DNA-binding domain but instead assist the DNA-binding domain being tethered onto the promoter. This effect of activation domains on DNA binding is instrumental in determining how potent activators can induce steep transcriptional increases at low concentrations.

Localization of Menkes gene expression in the mouse brain; its association with neurological manifestations in Menkes model mice

Menkes gene (Mc1 or MNK, encoding putative copper-transporting ATPase) expression was investigated and compared in normal and macular mutant mouse brain. Northern blot analysis showed a distinct 8.3-kb transcript and no obvious difference in size or extent in normal mice and macular mutants on postnatal days 0, 4, 7, 10 or 13. In situ hybridization revealed that certain specific populations of cells in the brain express Menkes mRNA, and that their localization in normal and mutant mice did not differ and was conserved on days 4, 10 and 13. The most intense hybridization signals were observed in the hippocampal CA1 region and dentate gyrus, the olfactory bulb nuclei, the cerebellar granular cell layer, the choroid plexus and the ependyma, with less intense signals in the hippocampal CA3 region and cerebellar Purkinje cells. In addition, necrotic neuronal cell death was predominantly observed in the CA3 region and the Purkinje cells of macular mice after postnatal day 10. The finding that the regions that had lower expression level of Menkes mRNA corresponded to those showing neuronal necrosis suggests that the Menkes gene may be responsible for the neuronal degeneration in some specific portions of the brain and clinical manifestations in this mutant.

Lipophilic, acid-stable, adenosine deaminase-activated anti-HIV prodrugs for central nervous system delivery. 3. 6-Amino prodrugs of 2'-beta-fluoro-2',3'-dideoxyinosine

A series of 6-substituted amino analogs of 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl) purines (F-ddN) has been synthesized and characterized with the objective of finding compounds which might be superior to existing drugs for the treatment of HIV in the central nervous system. These compounds are intended to be more lipophilic than the currently approved anti-HIV drugs for better blood-brain barrier penetration. Subsequent adenosine deaminase (ADA)-catalyzed hydrolysis of these prodrugs in the brain is expected to produce the anti-HIV agent, 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl)hypoxanthine (F-ddI). The new compounds, synthesized from the corresponding 6-chloro analog, include F-ddN which contain methylamino, ethylamino, dimethylamino, hydroxylamino, methoxyamino, benzyloxyamino, hydrazino, and nitro substituents in the 6-position. The 6-nitro analog was isolated as an unexpected product during the preparation of the 6-chloro derivative. Among the analogs with anti-HIV activity, the ethylamino and dimethylamino compounds are ca. 100 times more lipophilic than ddI or F-ddI. As expected, 2'-fluoro substitution protects the compounds from acid-catalyzed glycosylic cleavage. Only the hydroxylamino and nitro analogs underwent any nonenzymatic hydrolysis at pH 1.0 or 7.4. This reaction, however, results in hydrolysis of the group in the 6-position rather than glycosylic bond cleavage. ADA catalyzes the hydrolysis of the 6-substituents at rates which vary from slightly slower (NO2, 1.7x) to much slower (NHEt, 5000x) than F-ddA. The 6-dimethylamino analog is the only compound which possesses anti-HIV activity (ED50 18 microM) without ADA hydrolysis. With the exception of the two inactive alkoxyamino compounds, the other prodrugs exhibited cellular protection in the HIV-1/PHA-PBM system with IC50 potencies of 7-40 microM.

Haploinsufficiency of parathyroid hormone-related peptide (PTHrP) results in abnormal postnatal bone development

Although apparently phenotypically normal at birth, mice heterozygous for inactivation of the gene encoding parathyroid hormone-related peptide (PTHrP) develop haplotype insufficiency by 3 months of age. In addition to histologic and morphologic abnormalities similar to those seen in homozygous mutants, heterozygous animals demonstrated alterations in trabecular bone and bone marrow. These included metaphyseal bone spicules which were diminished in volume, irregularly distributed, and less well developed than those seen in age-matched controls as well as bone marrow, which contained an inordinate number of adipocytes. A substantial reduction in PTHrP mRNA was detected in heterozygous tissue, while circulating parathyroid hormone (PTH) and calcium concentrations were normal. Thus, while a physiologic concentration of PTH was capable of maintaining calcium homeostasis, it was incapable of compensating for PTHrP haploinsufficiency in developing bone. In normal animals, both PTHrP and the PTH/PTHrP receptor were expressed predominantly in chondrocytes situated throughout the proliferative zone of the tibial growth plate. In the metaphysis, the PTH/PTHrP receptor was identified on osteoblasts and preosteoblastic cells situated in the bone marrow, while PTHrP was expressed only by osteoblasts. These observations indicate that postnatal bone development involves susceptible pathways that display exquisite sensitivity to critical levels of PTHrP and imply that the skeletal effects of PTH are influenced by locally produced PTHrP. Moreover, identification of both the ligand and its N-terminal receptor in metaphyseal osteoblasts and their progenitors suggests an autocrine/paracrine role for the protein in osteoblast differentiation and/or function. Impairment in this function as a consequence of PTHrP haploinsufficiency may critically influence the course of bone formation, resulting in altered trabecular architecture and perhaps low bone mass and increased bone fragility.

Immunohistochemical detection of 4-hydroxynonenal protein adducts in Parkinson disease

There is growing evidence that oxidative stress and mitochondrial respiratory failure with attendant decrease in energy output are implicated in nigral neuronal death in Parkinson disease (PD). It is not known, however, which cellular elements (neurons or glial cells) are major targets of oxygen-mediated damage. 4-Hydroxy-2-nonenal (HNE) was shown earlier to react with proteins to form stable adducts that can be used as markers of oxidative stress-induced cellular damage. We report here results of immunochemical studies using polyclonal antibodies directed against HNE-protein conjugates to label the site of oxidative damage in control subjects (ages 18-99 years) and seven patients that died of PD (ages 57-78 years). All the nigral melanized neurons in one of the midbrain sections were counted and classified into three groups according to the intensity of immunostaining for HNE-modified proteins--i.e., no staining, weak staining, and intensely positive staining. On average, 58% of nigral neurons were positively stained for HNE-modified proteins in PD; in contrast only 9% of nigral neurons were positive in the control subjects; the difference was statistically significant (Mann-Whitney U test; P < 0.01). In contrast to the substantia nigra, the oculomotor neurons in the same midbrain sections showed no or only weak staining for HNE-modified proteins in both PD and control subjects; young control subjects did not show any immunostaining; however, aged control subjects showed weak staining in the oculomotor nucleus, suggesting age-related accumulation of HNE-modified proteins in the neuron. Our results indicate the presence of oxidative stress within nigral neurons in PD, and this oxidative stress may contribute to nigral cell death.

[Serum CA 19-9 levels in rheumatic diseases with interstitial pneumonia]

Serum CA 19-9 (2-3 sialyl Le(a)) is a marker of malignant disorder such as pancreas or gall bladder cancers. It has been reported that sera from patients with interstitial pneumonia show elevated level of CA 19-9. To investigate the relationship between the elevation of serum CA 19-9 (sCA 19-9) and the presence of pulmonary fibrosis, we examined the level of sCA 19-9 in sera from patients with rheumatic diseases with or without interstitial pneumonia (IP). The sCA 19-9 level was determined by enzyme-linked immunosorbent assay (ELISA). Fourteen sera of 129 (10.9%) patients with rheumatic diseases without malignant disorders were positive for sCA 19-9 when normal range was determined as less than 100 U/ml (mean +/- 5 SD), and 26.7% of sera from poly/dermatomyositis (PM/DM) and 11.8% of systemic sclerosis (PSS) were positive for CA 19-9. Whereas only 8.0% of rheumatoid arthritis (RA) was positive. Twelve (28.6%) of 42 rheumatic patients with IP showed positive levels for sCA 19-9 (mean 142.5 +/- 363.0 U/ml), whereas only two (2.3%) of 87 without IP were positive (mean 33.9 +/- 65.8 U/ml; p < 0.05). The correlation between the level of sCA 19-9 and pulmonary diffusing capacity (%DLCO) revealed an inverse correlation in 32 rheumatic patients with IP (r = -0.43, p < 0.05). Furthermore, the elevated sCA 19-9 levels decreased after treatment with corticosteroid and/or cyclophosphamide or cyclosporin A. Therefore, elevation of the level of sCA 19-9 seems to be involved in the pathogenesis of IP and sCA 19-9 will be a useful parameter for IP. It has been reported that the CA 19-9 is produced from the bronchial glands and suggested that during chronic fibrotic process of the lung, the metaplastic change of the bronchial glandular cells occur and the cells produce CA 19-9.

Comparison of mammary gland growth and some physiological parameters in a high mammary tumor strain of SHN mice and ICR, most popular and 'normal' mice

As a possible step in examining the difference between pathological models and most popular and 'normal' models, the mammary gland and some parameters were compared in SHN mice, a high mammary tumor strain, and ICR mice. SHN was lower than ICR in almost all urinary component levels as indicators of general metabolic activity in both the female and the male, and glucose tolerance in the female. Body weight and several organ weights including liver and kidneys were lower in SHN than in ICR. Normal and preneoplastic mammary gland growth and TGF alpha mRNA expression in the glands of the female were much higher in SHN than in ICR. These findings stress the importance of having a right knowledge of the parameters of 'normal' animals, especially for researchers using pathological models.

[A case of SLE with the onset of pleuritis showing eosinophilia and elevation of serum IgE]

A 19 year old female was admitted to our hospital with complaints of fever, dyspnea and chest pain. Chest x-ray film showed a massive right pleural effusion. She was diagnosed to have systemic lupus erythematosus (SLE) because of malar rash, serositis (pleuritis), positive antinuclear antibody and positive anti-DNA antibody. Then she was successfully treated with 50 mg/d prednisolone. This case was unusual and of interest in that she had eosinophilia in the peripheral blood and exudative pleural effusion and a marked elevation of serum IgE level despite no history of allergic diseases and no evidence of parasite infections.

Mucin-hypersecreting tumors of the pancreas: assessing the grade of malignancy preoperatively

BACKGROUND

Mucin-hypersecreting tumor of the pancreas (MHST) is a unique variant of pancreatic tumor, where mucin was excreted from the patulous orifice of the enlarged ampulla of Vater and the main pancreatic duct was dilated with excessive mucin. It is difficult to differentiate preoperatively between benign and malignant variants.

PATIENTS AND METHODS

A total of 18 patients with an MHST were retrospectively reviewed to identify possible indicators of malignancy. The 18 tumors consisted of 9 benign lesions (hyperplasia or adenoma with mild to moderate atypia), 2 borderline disorders (adenoma with severe atypia), and 7 malignant diseases (unequivocal adenocarcinoma).

RESULTS

The age, sex, and site of origin demonstrated no significant difference among the three groups. One of the 9 patients with the benign lesion was diabetic, while 4 of the 7 patients with the malignant variant were diabetic (P<0.05). All 9 benign lesions were confined to the side branch, while 4 of the 7 malignant diseases were located in the main pancreatic duct (P<0.05). The mean greatest diameters of these three variants were 3.2 cm, 3.3 cm, and 6.6 cm, respectively. The mean greatest diameter of the main pancreatic duct in the 7 malignant disorders were larger than in the 9 benign conditions (9.7 versus 5.4 mm, P <0.05). The mean diameter of the mural nodules in the 7 malignant tumors were larger than in the 9 benign lesions (20.5 versus 5.1 mm, P <0.05). The serum and mucin carcinoembryonic antigen and carbohydrate antigen 19-9 levels showed no substantial difference between the benign and malignant variants.

CONCLUSIONS

The presence of diabetes, large tumors (> or = 5 cm), marked dilatation of the main pancreatic duct (> or = 10 mm), main pancreatic duct type, and large mural nodules (> or = 10 mm) is strongly suggestive of a malignant variant of the MHST.

[Efficacy of cefditoren pivoxil in the treatment of acute otitis media due to benzylpenicillin-insensitive Streptococcus pneumoniae]

Clinical and bacteriological studies were carried out on cefditoren pivoxil (CDTR-PI) granule in infantile purulent acute otitis media treated at general practice settings and the following findings were obtained: 1. Two hundred forty eight strains were isolated from 210 patients, almost all of which (81.1%) harbored the following two strains: Streptococcus pneumoniae (42.3%) and Haemophilus influenzae (38.8%). Among S. pneumoniae, benzylpenicillin (PCG)-insensitive S. pneumoniae, (PISP) or PCG-resistant S. pneumoniae (PRSP) was 36.2%, corresponding to 15.3% of all the isolates and found in 18% of all patients. 2. The bacteria in the middle ear discharge and the nasopharyngeal swabs were correlated with conformity rate of more than 80% with regard to Streptococcus pyogenes, S. pneumoniae and H. influenzae but no Staphylococcus aureus was detected simultaneously from the two sources in any of the patients. S. aureus and coagulase-negative staphylococci (CNS) were considered to be contaminants that were originated from the external auditory meatus at the time of sampling. 3. Frequencies of isolation of S. pneumoniae from different age groups were higher in a lower age group between 0 and 4 years and those of PISP or PRSP had the similar tendency. 4. Antibacterial activities were determined for CDTR and related oral antibiotics against the strains of S. pneumoniae and H. influenzae as representative isolates. CDTR had stronger antibacterial activities against both bacteria than the reference antibiotics. CDTR was found to be transferred into the otorrhea at a mean concentration of 0.58 micrograms/ml after single administration of CDTR-PI granule formulation at 3 mg(potency)/kg. 5. As for bacterial eradication efficacies in the middle ear cavity and the nasopharynx, eradication rates were higher than 80% in the middle ear cavity in all cases without large differences among bacterial species but eradication rate of PISP was 30% in the nasopharynx, and it was significantly lower than those of PSSP and other bacteria. 6. In view of clinical effectiveness, the efficacy rate was 89.4% and bacteriological effects was 92.2%; in view of safety, adverse reactions were; observed in 9.5% and the rate of usefulness was 89.4%. 7. From above-stated results, CDTR-PI was considered as a useful oral antibiotic for infantile acute otitis media including PISP infections.

Site-directed mutagenesis at 134/135 in human growth hormone alters its in vivo half-life in the rat

It has been shown that human growth hormone (hGH) is attacked and digested at Arg(134)-Thr(135) by thrombin and plasmin, facilitating its further degradation in the plasma and tissues. To investigate the roles of the amino acids residues on the 134/135 site in the stability and half-life of the hormone in vivo, we have synthesized a mutant hGH, hGH(R134H, T135E), where Arg and Thr are replaced by His and Glu respectively. The mutant hGH showed an altered half-life time (7 min) as compared to that (11 min) for native form hGH, while the biological activity was not affected by the mutation.

Embolization for ruptured superior mesenteric artery aneurysms

Superior mesenteric artery (SMA) aneurysms are very uncommon. They are difficult to detect until they rupture and cause hypovolaemic shock. We performed embolization in four cases of aneurysm of branches of the superior mesenteric artery, succeeding in three cases without the need for surgical treatment. In the first case, the aneurysm was excised because of migration of a microcoil into the left hepatic artery. It was not retrieved because sufficient blood flow to the liver was shown on angiography after migration and no ischaemic change of liver was detected on laparotomy. In the second case, the aneurysm arose from the anterior pancreaticoduodenal artery. In the third case, the patient had two SMA aneurysms; one had been resected at surgery, another was revealed on follow-up angiography and embolized with microcoils. The fourth patient had a jejunal artery aneurysm with extravasation; haemostasis was achieved by packing it. In all four cases, no major complications were observed in the clinical course after embolization. Microcoils were considered to be the desirable embolic material, in order to prevent post-therapeutic ischaemic change. Embolization should be the treatment of choice for SMA aneurysms, because it is less invasive and takes less time than surgical treatment.

Hepatic bile acid synthesis and DNA synthetic rate after partial hepatectomy

The relationship between hepatic DNA synthetic rate and activity of cholesterol 7 alpha-hydroxylase, the rate limiting enzyme for bile acid synthesis, was examined in regenerating liver after partial hepatectomy or sham operation in rats. Hepatic cholesterol 7 alpha-hydroxylase activity was significantly (P < 0.001) suppressed on days 1 and 2, returned to the control level on day 3, and was significantly raised on day 7 after hepatectomy. The rate of DNA synthesis was significantly (P < 0.001) activated during the first 3 days after hepatectomy and returned to the control level on day 7. Enzyme activities regulating hepatic bile acid synthesis and DNA synthesis change inversely during liver regeneration after hepatectomy.

Clinico-pathological findings of asymptomatic intrahepatic cholangiocellular carcinoma: report of two cases and review of the literature

The prognosis of intrahepatic bile duct carcinoma (cholangiocellular carcinoma: CCC) is extremely poor unless detected at an early and curable stage. However, little is known about the clinico-pathological features of CCC resected at a symptom-free stage. We herein report the clinico-pathological findings in two asymptomatic patients who underwent resection. Their liver function tests showed elevated levels of gamma-glutamyl transpeptidase. An intrahepatic mass was first detected by ultrasonography, and subsequent direct cholangiography and cytological examination revealed the presence of carcinoma in both patients. Left or right hepatic lobectomy with caudate lobectomy and lymph node dissection with or without resection of the extrahepatic bile duct was carried out. The lesions were 2.5 and 2.8 cm in maximal size, originating from the intrahepatic bile duct of segment IV and I, respectively. Both were free from extrahepatic bile duct involvement, intrahepatic and lymph node metastases. However, even in a symptom-free stage, perineural invasion, vascular or lymphatic involvements were histologically proved in both cases, which may be an indication of poor prognosis after surgery alone.

Establishment of high- and low-invasion clones derived for a human tongue squamous-cell carcinoma cell line SAS

Distant-organ metastasis and regional lymph node metastasis are still the major cause of mortality of oral-cavity squamous-cell cancer (SCC). However, only a few studies have been undertaken to elucidate the mechanism of invasion and metastasis of oral SCC. In this study, we attempted to establish human oral SCC clones with different invasiveness, defined by endothelial cell monolayer assay, which can be used for the study of invasion and metastasis of oral SCC. We established five clones from the human oral SCC cell line SAS by a limiting-dilution method. Two distinct clones, SAS-L1 with very low invasive potential and SAS-H1 with very high invasive potential, were picked out by rat lung endothelial cell monolayer assay. The number of SAS-H1 that penetrated the rat lung endothelial cell monolayer was six fold higher than the number of SAS-L1. There were no differences of metalloproteinase production and cell adhesiveness to Matrigel of SAS-L1 and SAS-H1. However, SAS-H1 exhibited a higher migration ability than SAS-L1. This pair of clones would be a useful experimental model to help in the study of the invasiveness of human oral SCC.

Effects of intraoperative chemohyperthermia in patients with gastric cancer with peritoneal dissemination

BACKGROUND

The most common cause of noncurative resection and recurrence is gastric cancer is peritoneal seeding. However, the results of treatment of peritoneal dissemination with chemotherapy have been poor with 5-year survival rates of 0%.

METHODS

A new in vitro thermochemosensitivity test was performed on gastric cancer cells obtained from 19 surgically resected specimens by using tetrazolium-based colorimetric assay (MTT assay). A novel treatment of the intraoperative chemohyperthermia was undertaken in 83 patients with gastric cancer with peritoneal dissemination. After aggressive resection of primary tumor, lymph nodes, and peritoneal metastases, warmed saline solution containing mitomycin C 30 mg, etoposide 150 mg, and cisplatin 300 mg was introduced into the peritoneal cavity via a closed circuit continuous hyperthermic peritoneal perfusion (CHPP) for 60 minutes to keep the abdominal temperature at 42 degree to 43 degrees C by means of a heat exchange mechanism.

RESULTS

The in vitro thermochemosensitivity test that 43 degrees C enhanced the cytotoxin effects on gastric cancer cells under clinically achievable drug concentrations. During CHPP, drug concentrations of cisplatin, mitomycin C, and etoposide in the perfusate remained statistically higher than in the peripheral venous circulation. Among 43 evaluable patients with residual peritoneal seeding, eight (19%) and nine (21%) exhibited complete response and partial response, respectively. The overall 1- and 5-year survival rates were 43% and 11%, respectively. Patients who underwent complete resection survived significantly longer than those with residual disease, and those with complete response had a significantly better prognosis than did those with partial response, and nonresponders. One-year survival rates with complete response, partial response or nonresponders were 88%, 27% and 22%, respectively. Five patients survived longer than 5 years.

CONCLUSIONS

Our triple treatment combining surgery and CHPP is an effective therapy for selected patients with gastric cancer with peritoneal dissemination.

Primary B-cell lymphoma of the breast in patient with smoldering type adult T-cell lymphoma

We report a patient with primary B-cell lymphoma of the breast complicated by smoldering type adult T-cell leukaemia (ATL). A 52-year-old Japanese woman complained of a rapidly enlarging lump in her right breast. She had been diagnosed to have smoldering type ATL since the age of 49. Aspiration cytology and subsequent excisional biopsy revealed B-cell type lymphoma of the breast. A gallium-scintigram showed abnormal accumulation in the bilateral breasts. Radiology was adopted because the lesion was localized only in the breasts and associated with smoldering type ATL. The lesions disappeared after the treatment.

Acute hypoxic pulmonary vascular response does not accompany plasma endothelin-1 elevation in subjects susceptible to high altitude pulmonary edema

We have previously shown that high altitude pulmonary edema-susceptible subjects (HAPE-S) have an accentuated pulmonary vascular response to hypoxia. In this study, we investigated the relationship between plasma endothelin-1 (ET-1) levels and the acute hypoxic pulmonary vascular response in HAPE-S and control subjects. In six HAPE-S and seven healthy subjects, we evaluated acceleration time/right ventricular ejection time (AcT/RVET) using Doppler echocardiography, and measured plasma ET-1 levels by radioimmunoassay (RIA) before and after 5 minutes of breathing 10% oxygen. The HAPE-S showed a significantly increased pulmonary vascular response to hypoxia compared with healthy subjects. However, no statistically significant changes of plasma ET-1 levels were observed before and after hypoxia in both groups. We conclude that the increased pulmonary vascular response to acute hypoxia in HAPE-S may not be related to ET-1 release.

Mitochondrial DNA mutations associated with the 11778 mutation in Leber's disease

To clarify the characteristics of possible synergestic mitochondrial DNA (mtDNA) mutations associated with Leber's hereditary optic neuropathy (LHON), we analyzed the entire nucleotide sequences of mitochondrial genome of two Japanese patients from independent pedigrees harboring the 11778 mtDNA mutation, and compared their sequences with those of 47 disease and 6 normal controls. We have detected several unique mutations in the mtDNA in addition to the 11778 mutation. Two nucleotide substitutions, an A-to-G transition at position 856 in the 12S rRNA gene and an A-to-G transition at 14692 in the T psi C loop of the tRNA(Glu) gene, occurred at highly conserved sites among various species. These mutations in combination with the 11778 mutation might synergetically contribute to the pathogenesis of LHON.