Loss of Ftsj1 perturbs codon-specific translation efficiency in the brain and is associated with X-linked intellectual disability

FtsJ RNA 2'-O-methyltransferase 1 (FTSJ1) gene has been implicated in X-linked intellectual disability (XLID), but the molecular pathogenesis is unknown. We show that Ftsj1 is responsible for 2'-O-methylation of 11 species of cytosolic transfer RNAs (tRNAs) at the anticodon region, and these modifications are abolished in Ftsj1 knockout (KO) mice and XLID patient-derived cells. Loss of 2'-O-methylation in Ftsj1 KO mouse selectively reduced the steady-state level of tRNA^Phe in the brain, resulting in a slow decoding at Phe codons. Ribosome profiling showed that translation efficiency is significantly reduced in a subset of genes that need to be efficiently translated to support synaptic organization and functions. Ftsj1 KO mice display immature synaptic morphology and aberrant synaptic plasticity, which are associated with anxiety-like and memory deficits. The data illuminate a fundamental role of tRNA modification in the brain through regulation of translation efficiency and provide mechanistic insights into FTSJ1-related XLID.

Pancreatic B-cell function is altered by oxidative stress induced by acute hyperglycaemia

AIMS

Type 2 diabetes is preceded by a symptom-free period of impaired glucose tolerance (IGT). Pancreatic B-cell function decreases as glucose intolerance develops. In many patients with IGT, fasting blood glucose is within normal limits and hyperglycaemia occurs only postprandially. We examined whether pancreatic B-cell function changes during acute hyperglycaemia induced by oral glucose loading.

METHODS

We calculated the insulinogenic index (I.I.) as an indicator of pancreatic B-cell function and measured serum levels of thioredoxin, a marker of cellular redox state, and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of oxidative stress, during a 75-g oral glucose tolerance test (OGTT) in 45 subjects [24 patients with normal glucose tolerance (NGT), 14 with IGT and seven with Type 2 diabetes].

RESULTS

Thioredoxin levels decreased after glucose loading [66.1 +/- 23.7, *59.3 +/- 22.4, *49.3 +/- 21.2 and *37.7 +/- 18.0 ng/ml, fasting (0 min) and at 30, 60 and 120 min, respectively; *P < 0.001 vs. fasting]. In contrast, concentrations of 8-OHdG peaked at 30 min and then gradually decreased (0.402 +/- 0.123, *0.440 +/- 0.120, 0.362 +/- 0.119 and 0.355 +/- 0.131 ng/ml, *P < 0.05 vs. fasting, P < 0.01 vs. 30 min). The insulinogenic index correlated with the change in thioredoxin levels (r = 0.34, P < 0.05). However, there was no relationship with the change in 8-OHdG levels from 0 to 30 min.

CONCLUSIONS

Hyperglycaemia in response to oral glucose impairs pancreatic B-cell function with decreasing thioredoxin levels. The augmented oxidative stress induced by hyperglycaemia may affect the cellular redox state. These findings strongly suggest that repeated postprandial hyperglycaemia may play an important role in the development and progression of diabetes mellitus.

Characterization of 17beta-hydroxysteroid dehydrogenase type 4 in human ovarian surface epithelial cells

The human ovarian surface epithelium (hOSE) is a single layer of mesothelial-type primitive epithelial cells that are potential estrogen targets. It has been reported that hOSE cells can produce estrogen. However, the mechanisms that regulate estrogen level(s) in hOSE cells are not yet known. To elucidate the enzymes involved in these reactions, we examined gene expression of 17beta-hydroxysteroid dehydrogenases (17beta-HSDs) in primary hOSE (POSE) and OSE2a cells using RT-PCR. We found that POSE cells and cells of the immortalized hOSE line, OSE2a, bidirectionally converted estrone (E1) and 17beta-estradiol (E2). Both cell types expressed mRNA for 17beta-HSD type 1 (17beta-HSD1), suggesting that the enzyme is involved in the E1 to E2 conversion. Interestingly, both cells expressed 17beta-HSD4 mRNA but not 17beta-HSD2 mRNA. We prepared an antibody against the carboxyl terminal of 17beta-HSD4 (anti-17beta-HSD4 antibody), which recognized the 80 and 48 kDa proteins in POSE and OSE2a cells based on immunoblot analysis. Furthermore, immunohistochemical study revealed the presence of 17beta-HSD4 in hOSE cells in the human ovary. These results suggest that 17beta-HSD4 is involved in estrogen inactivation and may protect against an excessive accumulation of E2 in hOSE cells.

Clinical results of aortic arch replacement using a four branched prosthetic graft

AIM

The aim of this study was to evaluate the operative techniques of total arch replacement, the clinical results and the survival curves of patients following this procedure.

METHODS

Since December 2001, 92 patients have undergone surgical treatment for aortic dissection and aneurysm. The total aortic arch replacement was performed in 24 of these patients. There were 16 men and 8 women, and the age range was 42 to 81 years with a mean age of 59.4 years. As the operative technique for total arch replacement, we used the 4-branched prosthetic graft, selective cerebral perfusion (SCP), continuous cold blood cardioplegia (CCBC), and open distal anastomosis under circulatory arrest. The combined operations were coronary bypass grafting in 4 patients, aortic valve suspension in 1 patient and a Bentairs procedure in 1 patient. Eleven (73.3%) patients with acute dissection required emergency operation.

RESULTS

The hospital mortality rate was 25% (6 of the 24 patients). The causes of death were multiple organ failure (MOF) due to renal and mesenteric ischemia in 3 patients, cerebral infarction in 2 patients, myonephropathic metabolic syndrome (MNMS) in 1 patient, respectively. The data concerning extracorporeal circulation was 204+/-53 min in total pump time, 136+/-43 min in aortic cross clamp time, 83+/-14 min in SCP time and 48+/-10 min in circulatory arrest time, respectively. The long-term result in actuarial survival rate was 76% for 5 years.

CONCLUSION

We consider the technique of total arch replacement using 4-branched prosthetic graft, SCP, CCBC, and open distal anastomosis is a useful operative method in patients with aortic aneurysm.

Recovery of an impalement and transfixion chest injury by a reinforced steel bar

A 36-year-old man was admitted to our hospital because of impalement injury due to a downwards fall upon some reinforced steel rods. An emergency operation was performed using percutaneous cardiopulmonary support (PCPS). The steel rods were taken out in the operating room. The heart, great vessels, vertebrae, and spinal cord were not involved in the impalement wounds. We performed a bronchoplasty of the torn and separated right main bronchus, and repaired the impaled left lung without any pulmonary resection. He recuperated without sequelae.

Coronary artery bypass grafting in octogenarians

Preoperative profiles, postoperative complications, and the early and late results in 32 patients 80 yrs. of age and older (elderly group) who underwent coronary artery bypass grafting were compared with those in patients under 80 yrs. of age (control group). In the elderly group, the prevalence of patients with preoperative creatinine clearance (Ccr.) <50 l/day (34.4%), unstable angina pectoris (78.1%) and left main trunk disease (40.1%) was significantly higher than those in the control group. The incidences of arrhythmia and intensive care unit(ICU) syndrome were also significantly higher in the elderly group than in the control group, however, there was no death due to these complications. In the elderly group, one patient (3.1%) died in the hospital due to low cardiac output syndrome (LOS), while three patients (2.4%) of the control group died in the hospital. As for the long-term results, the 5-yr. survival rates for the elderly group and the control group were 82.6% and 85.2%, respectively, and the effectiveness of surgery was remarkable, with improved postoperative activity in 96.9% of the elderly group. These findings indicate that although the elderly patients have higher risks by undergoing surgery and have a disadvantage in the rate of postoperative complications, the postoperative improvement in activity and survival rate can be similar to those in the younger patients.

Glomangiopericytoma causing oncogenic osteomalacia. A case report with immunohistochemical analysis

A 47-year-old woman suffered from gait disturbance due to back pain and muscle weakness. Laboratory data showed serum hypophosphatemia, elevated alkaline phosphatase, and a normal level of ionized calcium. Radiological examinations revealed multiple pathologic fractures in the ribs and pubic rami. She had had no episode of familial or any other notable disorder, and so she was initially treated with medication for adult-onset osteomalacia. However, 19 years later (when she was 66 years old), she noticed a soft-tissue tumor in her buttock. The tumor was excised. The histological features were those of glomangiopericytoma characterized by both glomus tumor-like and hemangiopericytoma-like structures. After removal of the tumor, her symptoms disappeared immediately. Laboratory data normalized 8 months later. To our knowledge, this is the first report of oncogenic osteomalacia caused by glomangiopericytoma.

Melting and stone production using MSW incinerated ash

Most of the municipal solid waste (MSW) in Japan is incinerated and the generated ash is landfilled. However, environmental pollution problems have increased and Japan has decreased final disposal sites for landfills. With the application of a melting system, the volume of incinerated ash can be reduced and the effective use of melted slag is being developed for use in civil engineering works. However, the low strength of melted slag as a vitreous structure has limited its effective use. As a solution for this deficiency, a technology to crystallize melted slag into higher strength produced stones was developed. With the joint cooperation of Chiba Prefecture and Kamagaya City, a demonstration plant for melting and stone production with a capacity of 4.8 tons of incinerator ash per day was constructed. The demonstration test was conducted from May 1998 to June 1999 with satisfactory results stated below. Long-term stable operation and performance of the plant have been confirmed and effective applications of produced stones have been demonstrated on a commercial scale. The results are as follows. 1. A stable, continuous operation and good quality produced stones have been confirmed by treating more than 750 tons of MSW incinerated ash. 2. More than 99.9% of dioxins contained in the incinerated ash were decomposed, and the concentration of dioxins in produced stones were less than the detection limit set by Japanese environmental standards. 3. Leaching values of hazardous heavy metals of produced stones sufficiently met the environmental standard on soil pollution of the Environment Agency with superior leaching behavior for the vitreous slag, thus confirming their safe applications. 4. The effective application of produced stones for aggregate was tested based on Japanese Industrial Standards and every figure of test results met the Japanese standard values. The use of produced stones as raw materials for permeable pavement blocks has been confirmed in commercial construction for a park in Chiba Prefecture. Asphalt use was also demonstrated by paving a commercial roadway in Kamagaya City.