Stress fractures of the lateral tibial plateau after open wedge high tibial osteotomy could be delayed type III lateral hinge fractures.

PURPOSE: To examine the condition and triggers of stress fractures of the lateral tibial plateau (LTP) similar to type III lateral hinge fractures (LHFs) after open wedge high tibial osteotomy (OWHTO). METHODS: OWHTO was performed in 118 knees. They were examined for LHFs by computed tomography (CT). Patients were divided into the stress fracture group (Group SF) if they showed fracture lines on CT performed after starting weight-bearing walking and the normal group (Group N) for others. RESULTS: The mean age was significantly older in Group SF (P = 0.022). Preoperatively, Group SF showed a significantly higher tibio-femoral angle (TFA, P = 0.014). No significant differences were observed in TFA and weight-bearing line ratio after surgery. Correction angle was significantly higher in the SF group. And all of the SF were more than 13 degrees. There was no significant difference in LHF incidence between groups, whereas stress fracture incidence differed significantly for each type of LHF (chi-squared test, P = 0.0001): 14.6% of type I cases, 100% of type II cases, 0% of type III cases, and 6.1% of those without LHF. DISCUSSION: The load on the LTP is assumed to act as a shearing force in type II fractures, which may contribute greatly to stress fractures. In type III, stress fractures may not occur because of the load dispersed at the fracture part. The stress fracture site is similar to type III LHF, and this kind of fracture is thought to be a delayed type III because it occurs after patients start weight-bearing walking. Moreover, they are observed in type I cases with a stable hinge and in 6% of cases without LHF. This study showed that high varus knees corrected with a large correction angle may develop stress fractures. OWHTO requires attention to stress fractures of the LTP, which can be regarded as delayed type III, in those developing LHFs postoperatively or having a high varus knee preoperatively. CONCLUSION: These results indicated the possibility of stress fracture in LTP during weight-bearing exercise after OWHTO, which was regarded as a delayed type III fracture. The results showed that Correction angle was more than 13 degrees, and lateral hinge fracture type II of the Takeuchi classification was an inducement of this stress fracture. LEVEL OF EVIDENCE: Level IV.

Factors related to stress fracture after unicompartmental knee arthroplasty.

BACKGROUND/OBJECTIVE: Unicompartmental knee arthroplasty (UKA) is a low-invasive knee surgery that enables early recovery. Stress fracture of the medial tibial plateau (MTP) is a complication of UKA that prolongs treatment once it has occurred. We investigated factors affecting its occurrence. METHODS: The study subjects were 167 patients who underwent fixed-bearing UKA between 2009 and 2016 (45 men and 122 women of mean age 77 years, including 134 with osteoarthritis of the knee and 33 with spontaneous osteonecrosis). We measured bone mineral density, installation angle of the tibial component, and leg alignment in those patients who developed stress fracture within 3 months after UKA. RESULTS: Stress fracture did not occur in 155 patients (N group, 45 men and 110 women) and did occur in 12 (SF group, 12 women). The bone mineral density (BMD) of the proximal femur was significantly lower in the SF group, indicating that bone fragility may have contributed to stress fractures at this site. There was no significant difference in the preoperative tibio-femoral angle (TFA), however, postoperative TFA was larger and the magnitude of the change in the valgus direction (ΔTFA) was smaller in the SF group. DISCUSSION: In usual UKA for medial compartment, the leg is more extroverted postoperatively than preoperatively, and leaving the knee in the genu varus position, which places a greater load on the tibial component, may raise the risk of stress fracture. Although there was no difference between the two groups in the varus angle of the tibial component, in a scatter plot of postoperative TFA and the installation angle of the tibial component members of the SF group were concentrated in the region of high TFA and low varus angle. Varus of the leg and a low varus angle of the tibial component may thus be factors in the occurrence of stress fracture. CONCLUSION: Our results suggested that low BMD in the affected femur, large postoperative TFA, and a combination of large postoperative TFA and small varus angle of the tibial component may contribute to stress fracture of the MTP following UKA.

Screening and evolution of a novel protist xylose isomerase from the termite Reticulitermes speratus for efficient xylose fermentation in Saccharomyces cerevisiae.

BACKGROUND: The yeast Saccharomyces cerevisiae, a promising host for lignocellulosic bioethanol production, is unable to metabolize xylose. In attempts to confer xylose utilization ability in S. cerevisiae, a number of xylose isomerase (XI) genes have been expressed heterologously in this yeast. Although several of these XI encoding genes were functionally expressed in S. cerevisiae, the need still exists for a S. cerevisiae strain with improved xylose utilization ability for use in the commercial production of bioethanol. Although currently much effort has been devoted to achieve the objective, one of the solutions is to search for a new XI gene that would confer superior xylose utilization in S. cerevisiae. Here, we searched for novel XI genes from the protists residing in the hindgut of the termite Reticulitermes speratus. RESULTS: Eight novel XI genes were obtained from a cDNA library, prepared from the protists of the R. speratus hindgut, by PCR amplification using degenerated primers based on highly conserved regions of amino acid sequences of different XIs. Phylogenetic analysis classified these cloned XIs into two groups, one showed relatively high similarities to Bacteroidetes and the other was comparatively similar to Firmicutes. The growth rate and the xylose consumption rate of the S. cerevisiae strain expressing the novel XI, which exhibited highest XI activity among the eight XIs, were superior to those exhibited by the strain expressing the XI gene from Piromyces sp. E2. Substitution of the asparagine residue at position 337 of the novel XI with a cysteine further improved the xylose utilization ability of the yeast strain. Interestingly, introducing point mutations in the corresponding asparagine residues in XIs originated from other organisms, such as Piromyces sp. E2 or Clostridium phytofermentans, similarly improved xylose utilization in S. cerevisiae. CONCLUSIONS: A novel XI gene conferring superior xylose utilization in S. cerevisiae was successfully isolated from the protists in the termite hindgut. Isolation of this XI gene and identification of the point mutation described in this study might contribute to improving the productivity of industrial bioethanol.

Healing period after open high tibial osteotomy and related factors: Can we really say that it is long?

High tibial osteotomy (HTO) is a general procedure for the treatment of degenerative gonarthrosis. In recent years, it has been reported that opening wedge high tibial osteotomy (OWHTO) has become widespread with good results. Despite these facts, HTOs tend to be avoided due to the need for long-term postoperative treatment. To investigate the treatment period for total recovery (healing period) after OWHTO and the factors affecting it. There were 47 cases of medial type degenerative gonarthrosis who underwent OWHTO from 2008 through 2011. The definition of the healing period was based on the time-dependent changes of the Japanese Orthopaedic Association score, focusing especially on pain on walking and pain on ascending/descending stairs. This score was defined as the Ability score. In this study, the healing period ended when the Ability score reached its maximum or when it showed a perfect score. Patients' characteristics were examined to determine their effect on the healing period. The Ability score was 36.7 ± 10.1 (mean ± SD) before surgery and 51.6 ± 5.4 12 months after OWHTO. The healing period was 6.3 ± 3.9 months. Factors correlated with a longer healing period included female sex (correlation coefficient -0.35) and high BMI (correlation coefficient 0.33). Our study suggested that the healing period after OWHTO is approximately 6 months, and patients' BMI and sex appear to be related to this period. This information is expected to be helpful for counseling patients undergoing treatment for gonarthrosis. Level of evidence Therapeutic study, Level IV.

[Clinical efficacy of travoprost-timolol fixed combination on ocular hypotensive agents and ocular surface agents in Japanese glaucoma patients].

PURPOSE: To investigate the clinical effects of travoprost-timolol fixed combination on ocular hypotensive agents, ocular surface agents and adherence in Japanese glaucoma patients. METHODS: 28 Japanese glaucoma patients, who had used topical prostaglandin F2alpha analogue (28 eyes; PG group), were assigned to treatment with travoprost-timolol fixed combination. Reduction of intraocular pressure (IOP), grades of conjuctival follicle, conjuctival injection and keratoepitheliopathy, as well as interviews for topical administration, were evaluated. 38 patients, who switched from the topical prostaglandin F2alpha analogue and a beta-blocker to travoprost-timolol fixed combination (38eyes: PG+BB group) were also evaluated in the same manner. RESULTS: While IOP was significantly reduced in the PG group, IOP was not changed in the PG+BB group. Both groups showed no significant changes in scores for conjuctival follicle, keratoepitheliopathy, or interview. CONCLUSION: These results suggest that travoprost-timolol fixed combination reduces IOP and produces low toxicity on the ocular surface.

[Case of primary malignant lymphoma of the liver treated by R-CHOP therapy].

A 75-year-old man was admitted to our hospital because of right hypochondralgia. Computed tomography (CT) revealed a large tumor in the right lobe of the liver. Ultrasonography (US) showed vessels in the tumor. Needle biopsy specimens showed malignant lymphoma (Diffuse large B cell lymphoma). Ga scintigraphy and FDG-PET did not demonstrate other lesions and the definitive diagnosis was primary malignant lymphoma of the liver. CHOP with Rituximab therapy (R-CHOP therapy) was performed. After 8 courses of therapy the FDG-PET results were negative and we considered complete remission. We describe a case of primary malignant lymphoma of the liver treated successfully by R-CHOP therapy.

Double mutation of the PDC1 and ADH1 genes improves lactate production in the yeast Saccharomyces cerevisiae expressing the bovine lactate dehydrogenase gene.

Expression of a heterologous L: -lactate dehydrogenase (L: -ldh) gene enables production of optically pure L: -lactate by yeast Saccharomyces cerevisiae. However, the lactate yields with engineered yeasts are lower than those in the case of lactic acid bacteria because there is a strong tendency for ethanol to be competitively produced from pyruvate. To decrease the ethanol production and increase the lactate yield, inactivation of the genes that are involved in ethanol production from pyruvate is necessary. We conducted double disruption of the pyruvate decarboxylase 1 (PDC1) and alcohol dehydrogenase 1 (ADH1) genes in a S. cerevisiae strain by replacing them with the bovine L: -ldh gene. The lactate yield was increased in the pdc1/adh1 double mutant compared with that in the single pdc1 mutant. The specific growth rate of the double mutant was decreased on glucose but not affected on ethanol or acetate compared with in the control strain. The aeration rate had a strong influence on the production rate and yield of lactate in this strain. The highest lactate yield of 0.75 g lactate produced per gram of glucose consumed was achieved at a lower aeration rate.

Human leukocyte antigen DR status and clinical features in Japanese patients with type 1 autoimmune hepatitis.

AIM: Human leukocyte antigen (HLA) DR status affects the clinical features of autoimmune hepatitis. In Caucasians, patients with DR3 have poorer outcomes. In Japan, the relationship between HLA DR status and clinical features has yet to be fully examined. METHODS: We investigated 79 patients with type 1 autoimmune hepatitis who underwent liver biopsy and were screened for HLA DR status by the polymerase chain reaction sequence specific oligonucleotide hybridization method. RESULTS: Fifty-five patients had DR4 and 23 had DR2. Thirteen patients had both DR2 and DR4. None had DR3. Of patients aged <30 years, 70% did not have DR4. A tendency toward higher serum levels of immunoglobulin G was seen in patients with DR4 compared to those without, while patients with neither DR2 nor DR4 had lower serum levels of immunoglobulin G than those with only DR2 and those with only DR4. Patients with DR2 had a lower frequency of concurrentautoimmune disease. Concurrence of thyroid disease was seen only in patients with DR4. The cumulative incidental rate of the normalization of serum alanine aminotransferase levels within six months after the introduction of corticosteroid treatment was not associated with HLA DR status. CONCLUSION: HLA DR status is considered to affect the clinical features of Japanese patients with type 1 autoimmune hepatitis. Japanese patients with DR2 may have different clinical features from others. In addition, diagnoses of type 1 autoimmune hepatitis should be made carefully in Japanese patients with neither DR2 nor DR4 and in those aged <30 years.

Clinical features of Japanese type 1 autoimmune hepatitis patients with zone III necrosis.

AIM: In Caucasians in northern Europe and North America, type 1 autoimmune hepatitis is characterized by susceptibility to human leukocyte antigens DR3 and DR4, and patients with zone III necrosis more frequently have an acute onset of the disease and a lower frequency of cirrhosis than those without. In Japanese patients, however, type 1 autoimmune hepatitis is primarily associated with DR4, and there are almost no DR3-positive patients. Thus, the clinical features of Japanese patients with type 1 autoimmune hepatitis and zone III necrosis may be different from those reported previously for Caucasians. METHODS: We investigated 160 consecutive patients with type 1 autoimmune hepatitis (20 males and 140 females; median age, 55 years; range, 16-79 years). RESULTS: Forty-seven patients (29%) had zone III necrosis, and these patients had lower serum levels of albumin and higher serum levels of total bilirubin, aspartate aminotransferaseand alanine aminotransferase. Histologically, zone III necrosis was found more frequently in patients with acute hepatitis than in those with chronic hepatitis. However, there was no difference in the frequency of cirrhosis between patients with and without zone III necrosis. In addition, normalization of serum alanine aminotransferase levels within six months after the introduction of corticosteroid treatment was slightly more frequent in patients with zone III necrosis (95% vs. 88%). CONCLUSION: In Japanese patients, zone III necrosis may reflect not only acute autoimmune hepatitis, but also acute exacerbation of pre-existing chronic disease. Furthermore, patients with zone III necrosis may respond better to corticosteroid treatment than those without.

[Case report of asymptomatic arteriovenous malformation (AVM) of the pancreas; diagnostic advantage of three-dimensional computed tomography].

A 72-year-old man with diabetes mellitus and hypertension was admitted for further examination and therapy of diabetes. In order to evaluate his pancreas, abdominal computed tomography (CT) was performed, showing a space-occupying lesion (SOL) in the pancreatic uncus. He did not show any symptoms related to the pancreas or gastro intestinal tract. Three-dimensional CT (3D-CT) indicated that the SOL was not a solid tumor but a vessel fistula, fed by the superior mesenteric artery and the gastro duodenal artery, drained by the superior mesenteric vein. Abdominal angiography also showed its peculiar vessel structure, confirming arterio-venous (A-V) malformation in the pancreas. Pancreatic A-V malformation is a rare condition but should not be forgotten in the differential diagnosis of pancreatic SOL. Our case showed the advantages of 3D-CT with its low invasiveness and convenience for the diagnosis of A-V malformation in the pancreas.

The effect of pyruvate decarboxylase gene knockout in Saccharomyces cerevisiae on L-lactic acid production.

A plant- and crop-based renewable plastic, poly-lactic acid (PLA), is receiving attention as a new material for a sustainable society in place of petroleum-based plastics. We constructed a metabolically engineered Saccharomyces cerevisiae that has both pyruvate decarboxylase genes (PDC1 and PDC5) disrupted in the genetic background to express two copies of the bovine L-lactate dehydrogenase (LDH) gene. With this recombinant, the yield of lactate was 82.3 g/liter, up to 81.5% of the glucose being transformed into lactic acid on neutralizing cultivation, although pdc1 pdc5 double disruption led to ineffective decreases in cell growth and fermentation speed. This strain showed lactate productivity improvement as much as 1.5 times higher than the previous strain. This production yield is the highest value for a lactic acid-producing yeast yet reported.

D-lactic acid production by metabolically engineered Saccharomyces cerevisiae.

Poly D-lactic acid is an important polymer because it improves the thermostability of poly L-lactic acid by the stereo complex formation. We constructed a metabolically engineered Saccharomyces cerevisiae that produces D-lactic acid efficiently. In this recombinant, the coding region of pyruvate decarboxylase 1 (PDC1) was completely deleted, and two copies of the D-lactate dehydrogenase (D-LDH) gene from Leuconostoc mesenteroides subsp. mesenteroides strain NBRC3426 were introduced into the genome. The D-lactate production reached 61.5 g/l, the amount of glucose being transformed into D-lactic acid being 61.2% under neutralizing conditions. Additionally, the yield of free D-lactic acid was also shown to be 53.0% under non-neutralizing conditions. It was confirmed that D-lactic acid of extremely high optical purity of 99.9% or higher. Our finding obtained the possibility of a new approach for pure d-lactic acid production without a neutralizing process compared with other techniques involving lactic acid bacteria and transgenic Escherichia coli.

IGFBP-3 expression in hepatocellular carcinoma involves abnormalities in TGF-beta and/or Rb signaling pathways.

Insulin-like growth factor binding protein-3 (IGFBP-3) is a mediator of growth suppression signals and a putative tumor suppressor gene. The growth suppression mechanisms of IGFBP-3 have not been well clarified. We examined the expression of IGFBP-3 transcripts in human hepatocellular carcinoma (HCC) and the relationship between IGFBP-3 expression and the transforming growth factor-beta (TGF-beta) and/or retinoblastoma (Rb) signaling pathways. In situ hybridization revealed IGFBP-3 transcripts in cancer cells in 6 of 57 (10%) HCCs, including moderately and poorly differentiated HCCs with intrahepatic metastasis. In contrast, all lung metastatic nodules of 4 HCCs showed IGFBP-3 transcripts in cancer cells. The cDNA microarray showed that genes for the TGF-beta pathway and Rb were up-regulated in IGFBP-3-expressing HCCs. In 6 HCCs presenting IGFBP-3, immunohistochemical analyses showed abnormalities in the TGF-beta and/or Rb pathways; the loss of phosphorylated-Smad2 was observed in 2, and overexpression of phosphorylated-Rb was observed in the remaining 4 HCCs. The present study suggests that IGFBP-3 mediates growth suppression signals via the TGF-beta and/or Rb pathways in HCC.

Genetically engineered wine yeast produces a high concentration of L-lactic acid of extremely high optical purity.

For mass production of lactic acid, we newly constructed a transgenic wine yeast strain that included six copies of the bovine L-lactate dehydrogenase gene on the genome. On fermentation in inexpensive cane juice-based medium, L-lactate production of this recombinant reached 122 g/liter and the optical purity was 99.9% or higher.

Cellular distribution of telomerase reverse transcriptase in human hepatocellular carcinoma.

BACKGROUND AND AIM: Telomerase is the enzyme that synthesizes telomeric DNA, and the activation of telomerase is closely related to cellular immortality. Telomerase activity has been reported in many human cancer tissues and is regulated by the expression of human telomerase reverse transcriptase (hTERT). The aim of the present study was to identify hTERT-expressing cells in human liver tissues and evaluate the feasibility of the hTERT promoter for gene therapy of hepatocellular carcinoma (HCC). METHODS: The authors examined the cellular distribution of hTERT transcripts in surgically resected HCC by in situ hybridization. RESULTS: Among 20 samples, hTERT expression was observed in 15 HCC. Transcripts of hTERT were homogenously distributed in the cytoplasm of HCC cells in nine of 15 cases; six of 15 cases displayed a heterogeneous staining pattern. All poorly differentiated HCC that expressed hTERT showed a homogenous pattern of staining. None of the non-cancerous hepatocytes were positive for the transcripts, but infiltrating lymphocytes were faintly stained. The homogenous expression of hTERT was also observed in the vascular invasion of HCC. CONCLUSIONS: The results indicate that most HCC cells express hTERT RNA and that the promoter is a good candidate as a target for gene therapy. However, careful consideration must be taken concerning the potential effects on lymphocytes.

Reduced expression of insulin-like growth factor binding protein-3 and its promoter hypermethylation in human hepatocellular carcinoma.

Insulin-like growth factor binding protein-3 (IGFBP-3) is postulated to be a mediator of growth suppression signals. Reduced expression of the IGFBP-3 was observed in nine out of 12 human hepatocellular carcinomas (HCC) (75%). Promoter hypermethylation of the IGFBP-3 was detected in four out of 12 HCCs (33%) although mutations were not identified. The expression of IGFBP-3 was restored by the demethylating agent 5-aza-2'-deoxycytidine in HCC cell line with promoter hypermethylation (HepG2). As IGFBP-3 functions like a tumor suppressor gene, it may be used as a therapeutic target for HCC.