Inverse genetics tracing the differentiation pathway of human chondrocytes.

OBJECTIVE: Mammalian somatic cells can be reprogrammed into induced pluripotent stem cells (iPSCs) via the forced expression of Yamanaka reprogramming factors. However, only a limited population of the cells that pass through a particular pathway can metamorphose into iPSCs, while the others do not. This study aimed to clarify the pathways that chondrocytes follow during the reprogramming process. DESIGN: The fate of human articular chondrocytes under reprogramming was investigated through a time-coursed single-cell transcriptomic analysis, which we termed an inverse genetic approach. The iPS interference technique was also employed to verify that chondrocytes inversely return to pluripotency following the proper differentiation pathway. RESULTS: We confirmed that human chondrocytes could be converted into cells with an iPSC phenotype. Moreover, it was clarified that a limited population that underwent the silencing of SOX9, a master gene for chondrogenesis, at a specific point during the proper transcriptome transition pathway, could eventually become iPSCs. Interestingly, the other cells, which failed to be reprogrammed, followed a distinct pathway toward cells with a surface zone chondrocyte phenotype. The critical involvement of cellular communication network factors (CCNs) in this process was indicated. The idea that chondrocytes, when reprogrammed into iPSCs, follow the differentiation pathway backward was supported by the successful iPS interference using SOX9. CONCLUSIONS: This inverse genetic strategy may be useful for seeking candidates for the master genes for the differentiation of various somatic cells. The utility of CCNs in articular cartilage regeneration is also supported.

Proteinase 3-antineutrophil cytoplasmic antibody-(PR3-ANCA) positive necrotizing glomerulonephritis after restarting sulphasalazine treatment.

A 59-year-old woman with ulcerative colitis developed red eyes, pleural effusion, eosinophilia and urinary abnormalities after restarting of sulphasalazine treatment. Light microscopy of a kidney biopsy revealed segmental necrotizing glomerulonephritis without deposition of immunoglobulin or complement. Proteinase 3-antineutrophil cytoplasmic antibody (PR3-ANCA) titer was elevated at 183 ELISA units (EU) in sera (normal range less than 10 EU), myeloperoxidase-ANCA was negative. PR3-ANCA titer was 250 and 1,070 EU in pleural effusions on right and left side, respectively. Although cessation of sulphasalazine treatment resulted in improvements in fever, red eyes, chest pain, titer of C-reactive protein and volume of the pleural effusions, we initiated steroid therapy, because PR3-ANCA titer rose to 320 EU, eosinophil count increased to 1,100 cells/microl, and the pleural effusion remained. One month after steroid therapy, the pleural effusion disappeared, and PR3-ANCA titer normalized 3 months later. This case suggests that sulphasalazine can induce PR3-ANCA-positive necrotizing glomerulonephritis.

A non-acromegalic case of multiple endocrine neoplasia type 1 accompanied by a growth hormone-releasing hormone-producing pancreatic tumor.

Cases of acromegaly due to GHRHproducing pancreatic endocrine tumors have been reported. Here we present a case of a 31-yr-old nonacromegalic man with hyperparathyroidism and elevated serum IGF-I with normal serum GH levels. Serum GH was not suppressed below 1 ng/ml by the glucose tolerance test and increased in response to TR H and GHRH administration. Magnetic resonance imaging (MRI) revealed pituitary hyperplasia and an abdominal computed tomography (CT ) scan showed a tumor in the pancreatic tail. Plasma concentration of GHRH was elevated. Based on these clinical data, multiple endocrine neoplasia (MEN) type 1 was suspected. Three enlarged parathyroid glands were removed and a distal pancreatectomy was performed. Pathological examination of the parathyroid glands and pancreatic tumor showed nodular hyperplasia and a well-differentiated endocrine tumor, respectively, both compatible with MEN features. Immunohistochemistry revealed positive immunoreactivity for GHRH, SS , insulin, glucagon, chromogranin A, and pancreatic polypeptide in the pancreatic tumor. After pancreatic surgery, elevated levels of GHRH and IGF-I were normalized and pituitary hyperplasia definitely decreased in size. In cases of pituitary hyperplasia with elevated IGF-I, ectopic GHRH syndrome must be considered even if physical features of acromegaly are absent. It is also important to measure plasma GHRH concentrations in order to give a diagnosis.

Cloning and characterization of benzoate catabolic genes in the gram-positive polychlorinated biphenyl degrader Rhodococcus sp. strain RHA1.

Benzoate catabolism is thought to play a key role in aerobic bacterial degradation of biphenyl and polychlorinated biphenyls (PCBs). Benzoate catabolic genes were cloned from a PCB degrader, Rhodococcus sp. strain RHA1, by using PCR amplification and temporal temperature gradient electrophoresis separation. A nucleotide sequence determination revealed that the deduced amino acid sequences encoded by the RHA1 benzoate catabolic genes, benABCDK, exhibit 33 to 65% identity with those of Acinetobacter sp. strain ADP1. The gene organization of the RHA1 benABCDK genes differs from that of ADP1. The RHA1 benABCDK region was localized on the chromosome, in contrast to the biphenyl catabolic genes, which are located on linear plasmids. Escherichia coli cells containing RHA1 benABCD transformed benzoate to catechol via 2-hydro-1,2-dihydroxybenzoate. They transformed neither 2- nor 4-chlorobenzoates but did transform 3-chlorobenzoate. The RHA1 benA gene was inactivated by insertion of a thiostrepton resistance gene. The resultant mutant strain, RBD169, neither grew on benzoate nor transformed benzoate, and it did not transform 3-chlorobenzoate. It did, however, exhibit diminished growth on biphenyl and growth repression in the presence of a high concentration of biphenyl (13 mM). These results indicate that the cloned benABCD genes could play an essential role not only in benzoate catabolism but also in biphenyl catabolism in RHA1. Six rhodococcal benzoate degraders were found to have homologs of RHA1 benABC. In contrast, two rhodococcal strains that cannot transform benzoate were found not to have RHA1 benABC homologs, suggesting that many Rhodococcus strains contain benzoate catabolic genes similar to RHA1 benABC.

Multiplicity of aromatic ring hydroxylation dioxygenase genes in a strong PCB degrader, Rhodococcus sp. strain RHA1 demonstrated by denaturing gradient gel electrophoresis.

To address the multiplicity of aromatic ring hydroxylation dioxygenases, we used PCR amplification and denaturing gradient gel electrophoresis (DGGE). The amplified DNA fragments separated into five bands, A to E. Southern hybridization analysis of RHA1 total DNA using the probes for each band showed that band C originated from a couple of homologous genes. The nucleotide sequences of the bands showed that bands A, C, and E would be parts of new dioxygenase genes in RHA1. That of band B agreed with the bphA1 gene, which was characterized previously. That of band D did not correspond to any known gene sequences. The regions including the entire open reading frames (ORFs) were cloned and sequenced. The nucleotide sequences of ORFs suggested that the genes of bands A, C, and E may respectively encode benzoate, biphenyl, and polyhydrocarbon dioxygenases. Northern hybridization indicated the induction of the gene of band A by benzoate and biphenyl, and that of the gene of band C by biphenyl and ethylbenzene, supporting the above notions. The gene of band E was not induced by any of these substrates. Thus the combination of DGGE and Southern hybridization enable us to address the multiplicity of the ring hydroxylation dioxygenase genes and to isolate some of them.

[Three cases of severe hyponatremia under taking selective serotonin reuptake inhibitor (SSRI)].

The association between selective serotonin reuptake inhibitors(SSRIs) and hyponatremia has been documented throughout the world. In Japan, since SSRIs have recently come into use for patients with depression, there are only a few reports of hyponatremia associated with SSRIs. We present here three cases of the syndrome of inappropriate secretion of antidiuretic hormone(SIADH) associated with the administration of fluvoxamine for depression. They were admitted to our hospital because of deep coma, and revealed severe hyponatremia. Their serum sodium levels were 103-112 mEq/l, serum osmolalities were 227-241 mmol/kg, urine sodium levels were 38-107 mEq/l, and urine osmolalities were 352-781 mmol/kg. These patients were started on fluvoxamine 3 days-3 months previously. The diagnosis of SIADH in these patients was made based on hyponatremia, and low serum and high urine osmolalities. The fluvoxamine treatment was discontinued, and hypertonic saline was infused. Their serum sodium levels and osmolalities were subsequently normalized. None of the other known causes of hyponatremia, including diuretic therapy, tumors, and respiratory and central nervous system diseases, were present. High plasma AVP levels observed in the two cases suggest that SSRIs stimulate AVP secretion, thereby causing SIADH. Many reports have shown that people older than 70 years were at a particularly high risk of developing hyponatremia when SSRIs were used. In the future, since the use of SSRIs will be increasing, the water and electrolyte balance of elderly patients should be monitored carefully during SSRIs therapy.

Novel germline RET proto-oncogene mutations associated with medullary thyroid carcinoma (MTC): mutation analysis in Japanese patients with MTC.

Germ-like and somatic mutations in the RET proto-oncogene are associated with inherited and sporadic medullary thyroid carcinoma (MTC). The majority of patients with multiple endocrine neoplasia type 2A (MEN2A) and familial medullary thyroid carcinoma (FMTC) carry germ-line point mutations that result in the substitution of one of five cysteine residues. We investigated exons 10, 11, 13, 14 and 16 of the RET proto-oncogene in 33 unrelated Japanese patients with MTC. Eleven of the 33 cases (33%) were found to have germ-line mutations. Three previously unreported mutations in exon 10 and 11 were identified: one in codon 620, (TGC-->GGC), resulting in a cysteine to glycine substitution, and two in codon 630, (TGC-->TCC) and (TGC-->TAC), resulting in cysteine to serine and cysteine to tyrosine changes, respectively. The new mutations were present in the germ-line DNA of four unrelated patients for whom a family history of MTC had not been documented. Because the new RET alleles described here involve cysteine residues in a region of protein previously associated with FMTC and MEN2A, it is very likely that they represent mutations that predispose to the development of MTC.

Thyroid carcinoma metastasized to the sternum: resection of the sternum and reconstruction with acrylic resin.

Recently we resected and reconstructed the sternum in two female patients with thyroid carcinoma metastatic to the sternum. Histological diagnosis of the metastatic lesion was follicular carcinoma in the first case and papillary carcinoma in the second case. Reconstruction of the sternum was accomplished by using an acrylic resin plate alone in the first case and an acrylic resin plate sandwiched between layers of Marlex mesh (Marlex sandwich procedure) in the second case. In the first case the acrylic resin plate was directly fixed to the ribs with metallic wires, most of which snapped off later, and a small amount of exudate accumulated around the plate for a short period of time. In contrast, the postoperative course in the second case was uneventful and the Marlex sandwich procedure seemed superior in the chest wall reconstruction following resection of the sternum.

Clinicopathological study of clear-cell tumors of the thyroid: an evaluation of 22 cases.

Twenty-two cases of partial or wholly composed clear-cell thyroid tumors were reviewed to differentiate between a primary nodule and metastatic clear-cell renal carcinoma in the thyroid. Pathological reevaluation of HE-stained specimens, immunohistochemical observation using anti-thyroglobulin (TG) antibody, and periodic acid-Schiff (PAS) staining were performed. The pathological characteristics in metastases from the kidney have a greater tendency to demonstrate a strikingly clear cytoplasm with small nuclei, rich vascularization, and a trabecular arrangement of tumor cells than do primary thyroid cases. The immunohistochemical TG staining in conjunction with PAS staining for the recognition of follicular colloid could provide much more reliable information of primary cases compared to that using TG staining alone. Clinically, in primary cases, the female:male ratio is substantially higher while the mean age is lower than in metastatic cases reflecting differentiated thyroid carcinoma. In conclusion, immunohistochemical staining for TG with PAS staining for the recognition of follicular colloid proved to be the most sensitive method for identifying primary clear cell thyroid tumors. In addition, a careful assessment of past and/or present kidney disorders to rule out metastatic renal cell carcinoma is advisable. Age, gender, and physiological findings are also informative when differentiating between them.

[Arterial supply of the thyroid gland in the human fetuses].

Thyroid arteries were studied in 37 Japanese fetuses from 4 months to 9 months old. The results were as follows: (1) The occurrence of pyramidal lobe was 48.6%. (2) The patterns of the branches arising from the aortic arch were classified into four types. Type A was the most common type and was found in 91.9%. Anomalous types C, G and CG were found in only one each (2.7%). (3) In Type A, the arterial distribution to the thyroid gland was as follows; 1) The superior thyroid artery was found to be a single branch from the parent artery in 100% of cases on the right and in 94.1% on the left, in 2 cases it was found to be a thyro-lingual trunk on the left side. 2) The superior thyroid artery arose from the external carotid artery in 61.8% of cases on the right and in 47.0% on the left, from the divergent portion of the internal and external carotid arteries in 26.5% on both sides and from the common carotid artery in 11.7% on the right and in 26.5% on the left. 3) The inferior thyroid artery arose from the thyrocervical trunk in 93.9% on the right and in 84.8% on the left. The inferior thyroid artery was found to be absent in 2 cases (6.1%) on the right and in 5 cases (15.2%) on the left. 4) The thyroid ima artery was found in 15.2%. It arose from the brachiocephalic trunk in 4 cases and from the right common carotid artery in 1 case. (4) In the 3 anomalous types C, G and CG, the arterial distribution to the thyroid gland was as follows; 1) Type C was found in a 8-month-old fetus. The superior thyroid artery originated from the external carotid artery. The right inferior thyroid artery was absent and the left inferior thyroid artery was derived from the thyrocervical trunk. The thyroid ima artery branched from the brachiocephalic trunk. 2) Type G was found in a 7-month-old fetus. The superior thyroid artery originated from the external carotid artery. The inferior thyroid artery arose from the thyrocervical trunk. The thyroid ima artery branched from the right common carotid artery. 3) Type CG was found in a 8-month-old fetus.(ABSTRACT TRUNCATED AT 400 WORDS)