Preferential expression of RB1-inducible coiled-coil 1 in terminal differentiated musculoskeletal cells

RB1-inducible coiled-coil 1 (RB1CC1) is a nuclear DNA-binding protein that can induce RB1 (retinoblastoma 1) expression. RB1CC1 is abundantly expressed in human musculoskeletal and cultured osteosarcoma cells. The present study analyzed the expression of RB1CC1 and RB1 in osteosarcoma cells and in musculoskeletal cells of human embryos to evaluate the contribution of both genes to the maturational process of musculoskeletal cells. The amount of RB1CC1 message was closely related to RB1 expression in various osteosarcoma cell lines. RB1CC1 expression was difficult to detect in immature proliferating chondroblasts or myogenic cells in human embryos, but became obvious and prominent concomitantly with the maturation of osteocytes, chondrocytes, and skeletal muscle cells. RB1CC1 expression in these musculoskeletal cells increased with RB1 expression, which is linked to the terminal differentiation of many tissues and cells. In addition, the introduction of wild-type RB1CC1 decreased the formation of macroscopic colonies in the cell growth assay. Accordingly, both RB1CC1 and RB1 genes preferentially co-expressed and contributed to the maturation of human embryonic musculoskeletal cells, and may regulate the proliferative activity and maturation of tumor cells derived from these tissues.     

Case report of de novo dup(18p)/del(18q) and r(18) mosaicism

This is a report of a 27-year-old woman with an unusual de novo chromosomal abnormality. Mosaicism was identified in peripheral blood cells examined by standard G-bands by trypsin using Giemsa (GTG) analysis and fluorescence in situ hybridization (FISH) analysis with chromosome-18 region-specific probes, 46,XX,del(18)(pter → q21.33:)[41], 46,XX,r(18)(::p11.21 → q21.33::)[8], and 46,XX,der(18)(pter → q21.33::p11.21 → pter)[1]. On the other hand, the karyotype of periodontal ligament fibroblasts was nonmosaic, 46,XX, der(18)(pter → q21.33::p11.21 → pter)[50]. All cell lines appeared to be missing a portion of 18q (q21.33 → qter). The pattern of the dup(18p)/del(18q) in the rod configuration raises the possibility of an inversion in chromosome 18 in one of the parents. However, no chromosomal anomaly was detected in either parent. The most probable explanation is that de novo rod and ring configurations arose simultaneously from an intrachromosomal exchange. The unique phenotype of this patient, which included primary hypothyroidism and primary hypogonadism, is discussed in relation to her karyotype.     

Activation dependence of isotonic transient in response to step tension reduction in cardiac muscle segment during barium contracture

Summary To clarify the activation-dependence of dynamic mechanical characteristics of contracting cardiac muscle, we analysed the healthy central segment length (SL) response to step decrease in tension at two different levels of barium contracture (0.2 mM and 0.5 mM Ba²⁺) in rat papillary muscles with a fixed initial SL. The time course of this response is thought to reflect the kinetics of actin-myosin interaction. The muscle was released stepwise from the steady contracture tension (T_c) to new steady tension levels (T_r) of varying magnitudes at 22° C. The SL responses consisted of four phases at T_r/T_c > 0.3. The amplitude of shortening in the second phase, after the initial rapid and minute shortening in the first phase, increased with an increase in amplitude of step tension reduction, and was greater at the higher activation level when compared at an identical amount of T_r/T_c. The fourth phase, after the remarkable lengthening in the third phase, was an extremely slow and minute shortening toward a new steady SL under the new tension. The duration of the second and third phase was quite insensitive to activation level at T_r/T_c > 0.85, but became longer at the higher activation level with larger amounts of tension reduction. The velocity measured from the initial quasi-steady SL shortening in the second phase increased significantly with the increase in activation level. These results are discussed in terms of cross-bridge kinetics underlying the isotonic SL transients at two different activation levels.     

ARK5 expression in colorectal cancer and its implications for tumor progression

A novel member of the human AMPK family, ARK5, was recently discovered to be a key molecule in mediating cancer cell migration activity in human pancreas cancer cell line PANC-1, and its activation was found to be induced by Akt-dependent phosphorylation at Ser 600. DNA array analysis with 241 paired cDNAs from 13 different types of tumors and corresponding normal tissues derived from cancer patients revealed ARK5 overexpression in the samples of colorectal cancer. ARK5 expression was measured and an in vitro invasion assay was performed in six human colorectal cancer cell lines, WiDr, HCT-15, DLD-1, SW620, LoVo, and SW480, and since high invasion activity was concordant with higher ARK5 expression, ARK5 expression was examined in relation to tumor progression and metastatic activity in clinical samples. In 56 clinical samples of primary colorectal cancers and their liver metastases, higher ARK5 expression was observed in the samples from more advanced cases, and much higher expression was observed in the liver metastases. In situ hybridization analysis showed ARK5 overexpression in tumor cells. Based on these findings, we propose that ARK5 overexpression is involved in tumor progression of colon cancer clinically.     

Usefulness of continuous air tonometry for evaluation of splanchnic perfusion during cardiopulmonary bypass

Although gastric mucosal tonometry has been reported as a useful method to assess splanchnic perfusion during cardiovascular surgery, the conventional discontinuous method of tonometry (saline tonometry) was cumbersome and prone to systematic errors. A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 10 minutes) measurement of gastric regional CO2 (PrCO2) and may be more suitable as a monitoring system in cardiac patients. We evaluated the usefulness of continuous air tonometry as a marker of splanchnic perfusion during cardiopulmonary bypass (CPB). In 19 patients (53-79 years, mean 63 years) who underwent cardiovascular surgery under standard CPB with mild hypothermia (32 degrees C) from January 2001 to May 2002, the PrCO2 and calculated intramucosal pH (pHi) of gastric tonometry was monitored using Tonocap, and their relation to postoperative visceral organ function was evaluated. The pHi significantly increased after initiation of CPB from 7.32 +/- 0.07 to 7.43 +/- 0.10 (p < 0.05) and then consistently decreased in all patients to 7.39 +/- 0.09 at the end of CPB. The value of PrCO2 significantly (p < 0.01) correlated with the value of pHi. The lowest value of pHi during CPB was significantly related to blood urea nitrogen (r = -0.75, p < 0.05), serum creatinine (r = -0.78, p < 0.05), creatinine clearance (r = 0.68, p < 0.05) on postoperative day 1, and blood urea nitrogen (r = -0.84, p < 0.01) on day 3. In contrast, arterial blood lactate level, venous oxygen saturation, and routinely measured hemodynamics (e.g., pump flow, arterial pressure) during CPB were unrelated to the postoperative visceral organ function. These results suggest that continuous monitoring of gastric regional CO2 and pHi by air tonometry system is useful for the evaluation of splanchnic perfusion during CPB and may contribute to improve CPB technique by allowing the early detection of visceral malperfusion.     

Lung Infection Caused by Gordona aurantiaca (Rhodococcus aurantiacus)

We report that Gordona aurantiaca (Rhodococcus aurantiacus) caused a lung infection in humans. The case of a 50-year-old male farmer is shown. This is the first report of infection by this organism.     

Two closely related ubiquitin C-terminal hydrolase isozymes function as reciprocal modulators of germ cell apoptosis in cryptorchid testis

The experimentally induced cryptorchid mouse model is useful for elucidating the in vivo molecular mechanism of germ cell apoptosis. Apoptosis, in general, is thought to be partly regulated by the ubiquitin-proteasome system. Here, we analyzed the function of two closely related members of the ubiquitin C-terminal hydrolase (UCH) family in testicular germ cell apoptosis experimentally induced by cryptorchidism. The two enzymes, UCH-L1 and UCH-L3, deubiquitinate ubiquitin-protein conjugates and control the cellular balance of ubiquitin. The testes of gracile axonal dystrophy (gad) mice, which lack UCH-L1, were resistant to cryptorchid stress-related injury and had reduced ubiquitin levels. The level of both anti-apoptotic (Bcl-2 family and XIAP) and prosurvival (pCREB and BDNF) proteins was significantly higher in gad mice after cryptorchid stress. In contrast, Uchl3 knockout mice showed profound testicular atrophy and apoptotic germ cell loss after cryptorchid injury. Ubiquitin level was not significantly different between wild-type and Uchl3 knockout mice, whereas the levels of Nedd8 and the apoptotic proteins p53, Bax, and caspase3 were elevated in Uchl3 knockout mice. These results demonstrate that UCH-L1 and UCH-L3 function differentially to regulate the cellular levels of anti-apoptotic, prosurvival, and apoptotic proteins during testicular germ cell apoptosis.