Effects of Endogenous and Exogenous Prostaglandin E2on the Proliferation and Differentiation of a Mouse Cementoblast Cell Line (OCCM-30)

BACKGROUND

Cementum formation is considered to be a critical event for successful regeneration of periodontal tissues. Cementoblasts share many characteristics with osteoblasts. Prostaglandin E(2) (PGE(2)) is an important local factor in bone metabolism. Although the effects of PGE(2) on osteoblasts are well known, its effects on cementoblasts have not yet been established. We examined the effects of PGE(2) on proliferation and differentiation in a mouse cementoblast cell line, OCCM-30 cells.

METHODS

OCCM-30 cells were treated with three concentrations of PGE(2) (10, 100, and 1,000 ng/ml). Cell number, alkaline phosphatase (ALP) activity, and expression for mineralization-related genes were determined. Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa B (NF-kappaB) ligand (RANKL) expression were also examined by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The addition of PGE(2) at the highest dose used in this study suppressed cell proliferation of OCCM-30 cells. The expression of mineralization-related marker mRNA, such as type 1 collagen, ALP, bone sialoprotein (BSP), and osteocalcin (OCN), was constitutively detected in OCCM-30 cells. PGE(2) dose dependently stimulated ALP activity and BSP-mRNA expression in OCCM-30 cells at day 3. Transcripts for OPG and RANKL and the protein level of OPG in culture media were upregulated with PGE(2) stimulation.

CONCLUSION

These results demonstrate that PGE(2) suppressed cementoblast proliferation but stimulated ALP activity and the BSP-mRNA level, suggesting a role of PGE(2) in controlling cementoblast differentiation, and further indicate that PGE(2) modulates RANKL and OPG expression in cementoblasts; the increase of OPG secreted from cementoblasts with PGE(2) stimulation may be essential to protect the root surface from resorption.

Periostin is frequently overexpressed and enhances invasion and angiogenesis in oral cancer

Oral squamous-cell carcinoma (OSCC) is one of the most common types of human cancer. Typically OSCC cells show persistent invasion that frequently leads to local recurrence and distant lymphatic metastasis. We previously identified Periostin as the gene demonstrating the highest fold change expression in the invasive clone by comparing the transcriptional profile of parent OSCC cell line and a highly invasive clone. Here, we demonstrated that Periostin overexpression enhanced invasiveness in oral cancer cell lines. To know the role of Periostin in invasion, angiogenesis and metastasis in OSCC cases, we first examined the expression of Periostin mRNA in 31 OSCC cases by RT-PCR and Periostin protein in 74 OSCC cases by immunohistochemistry. Then, we compared the Periostin expression with invasion pattern, metastasis and blood vessel density. Periostin mRNA and protein overexpression were frequently found in OSCC cases and Periostin expression was well correlated with the invasion pattern and metastasis. Moreover, blood vessel density of Periostin-positive cases was higher than those of Periostin-negative cases. Interestingly, recombinant Periostin enhanced capillary formation in vitro in a concentration-dependant manner. In summary, these findings suggest that Periostin may promote invasion and angiogenesis in OSCC, and that Periostin can be a strong marker for prediction of metastasis in oral cancer patients.

Apoptosis-independent Poor Morphology of Bovine Embryos Produced by Multiple Ovulation

In multiple ovulation and embryo transfer (MOET) programmes in cattle, a considerable number of morphologically poor-quality embryos continue to be produced; this is one of the limiting factors of the technique. Apoptosis has often been implicated in developmental arrest and fragmentation; these are regarded as poor traits of embryonic quality in mammalian pre-implantation embryos. In the present study, apoptosis was assessed in morphologically poor-quality embryos in comparison with good-quality embryos that were recovered from a MOET programme. Retarded embryos (two to 16 cell stage), morulae with severe fragmentation and morphologically good-quality morulae recovered from superstimulated cows at day 7 post-insemination were subjected to TdT-mediated dUTP nick-end labelling (TUNEL) and Hoechst staining. Cell nuclei that showed both TUNEL staining and apoptotic morphology were considered to be apoptotic. Apoptotic index (AI) was calculated as the percentage of apoptotic cells per embryo. Fifteen of 17 retarded embryos and 10 of 15 morphologically poor-quality morulae did not show signs of apoptosis. The mean AIs in the morphologically poor-quality embryos (two to 16 cell stage, 2.2%; poor morulae, 1.3%) were as low as that in the good-quality embryos (2.9%). These results suggest that another mode of developmental arrest and/or fragmentation that is independent of apoptosis occurs in morphologically poor-quality embryos recovered from MOET programmes.

MRI findings of haematomyelia in a dog with spontaneous systemic haemorrhage

A 7-year-old female cross-breed dog was brought to Nihon University Animal Medical Center for investigation of tetraplegia. Lameness in the pelvic limbs, that had developed 2 weeks previously, had progressed to tetraplegia. On magnetic resonance imaging of the spinal cord, isointensity was detected from C2 to C4 and T12 to T13, isointensity and hyperintensity were intermingled from L3 to L4, and hyperintensity was detected from L5 to L7 by T1-weighted imaging. On T2-weighted imaging, hyperintensity was detected in all regions described above. The dog recovered from anaesthesia, but died during the day from systemic bleeding as the result of a coagulopathy of unknown aetiology. Histopathological examination revealed haematomyelia in these regions of the spinal cord. This is the first report of magnetic resonance imaging findings of haematomyelia in canine spontaneous systemic haemorrhage. It appeared that the differences in the findings of T1-weighted imaging along the spinal regions reflected time-lags in the occurrence of bleeding.

Two-year follow-up of chronic stimulation of the posterior subthalamic white matter for tremor-dominant Parkinson's disease

OBJECTIVE

To determine the efficacy and safety of unilateral deep brain stimulation on the posterior subthalamic white matter, including the zona incerta (ZI) and the prelemniscal radiation (PRL), for tremor-dominant parkinsonian patients and to determine the exact location of electrodes that were most effective.

METHODS

Eight parkinsonian patients with severe resting tremor underwent unilateral stimulation of the ZI/PRL by use of stereotactic guidance. Electrophysiological targeting was obtained by macrostimulation and by somatosensory evoked potentials recorded directly through a quadripolar deep brain stimulation lead. Postoperative computed tomographic scans and magnetic resonance images were performed to confirm anatomic location of the electrode. Parkinsonian motor disabilities were evaluated by use of the Unified Parkinson's Disease Rating Scale in the medication-off state before surgery and every 6 months after electrode implantations.

RESULTS

The mean location of the clinically effective contacts was in the posterior subthalamic white matter, including the ZI and the PRL (mean, 5.6 +/- 1.2 mm posterior to the midcommissural point, 3.2 +/- 1.1 mm inferior to the anterior commissure-posterior commissure line, and 10.5 +/- 1.2 mm lateral to the midline). At 24 months after operation, ZI/PRL stimulation resulted in significant improvement in mean Unified Parkinson's Disease Rating Scale motor score by 44.3%, contralateral tremor by 78.3%, contralateral rigidity by 92.7%, and contralateral akinesia by 65.7% above the "off-stimulation" scores. Handwriting, posture, and gait were also improved. There were no or only mild adverse events.

CONCLUSION

Unilateral ZI/PRL stimulation is a reliable and long-term therapeutic modality and can be considered another surgical target for the treatment of tremor-dominant Parkinson's disease.

Ubiquitin-dependent degradation of SnoN and Ski is increased in renal fibrosis induced by obstructive injury

Transforming growth factor-beta (TGF-beta) plays a critical role in the progression of renal fibrosis. The activity of TGF-beta is tightly controlled by various mechanisms, among which antagonizing Smad-mediated gene transcription by co-repressors represents one of the important components. We investigated the expression, degradation, and ubiquitination of Smad transcriptional co-repressors SnoN (ski-related novel gene N) and Ski (Sloan-Kettering Institute proto-oncogene) in renal fibrogenesis. We also studied the involvement of Smad-ubiquitination regulatory factor 2 (Smurf2) in ubiquitination of SnoN protein. The kidneys of mice with unilateral ureteral obstruction (UUO) and those of sham-operated mice were used. Renal lesions and the expression of TGF-beta1, type I collagen, SnoN, Ski, and Smurf2 were examined by immunohistochemistry, Western blot, and/or real-time reverse transcriptase-polymerase chain reaction. Degradation and ubiquitination of SnoN/Ski proteins were also investigated. The obstructed kidneys of UUO mice showed progressive tubulointerstitial fibrosis, high expression levels of TGF-beta1, type I collagen, SnoN and Ski mRNAs, and low levels of SnoN and Ski proteins. Both degradation and ubiquitination of SnoN/Ski proteins were markedly increased in the obstructed kidneys, in which Smurf2 expression was increased. Smurf2 immunodepletion in extracts of obstructed kidneys resulted in reduced ubiquitination of SnoN. Our results suggest that the reduction of SnoN/Ski proteins resulting from increased ubiquitin-dependent degradation is involved in the progression of tubulointerstitial fibrosis.

Characteristics of periodontal ligament subpopulations obtained by sequential enzymatic digestion of rat molar periodontal ligament

Periodontal ligament (PDL) consists of different cell populations in various differentiation stages. In the present study, we isolated cell populations from rat molar PDL by sequential enzymatic digestion and characterized growth potential and mineralization activity of the PDL subpopulations (PDL-SP) to throw light on the mechanism of PDL remodeling and, in its turn, periodontal tissue regeneration. PDL attached to extracted rat molars was digested 2 mg/ml collagenase and 0.25% trypsin at 37 degrees C for 30 min. Then four consecutive digestions were performed for 20 min each in a fresh digestive solution. The solutions were centrifuged to collect released cells and 5 PDL subpopulations (30M-, 50M-, 70M-, 90M-and 110M-PDL-SP) were obtained. Light microscopic observation showed that about a half of PDL in width attached on the root surface of extracted teeth and 30M-PDL-SP was considered to contain cells mainly from middle portion of PDL. Scanning electron microscopic examination indicated that 110M-PDL-SP was enriched by root lining cementoblastic cells. 30M-PDL-SP showed a high level of proliferative activity. Although the growth potential of a subpopulation decreased in PDL-SP toward the root surface, 110M-PDL-SP had a high proliferative activity equivalent to that of 30M-PDL-SP. Analyses of alkaline phosphatase (ALP) and mineralization activities showed that higher activities in PDL-SP toward the surface of roots and that 110M-PDL-SP had the highest activity of ALP and the largest number of mineralization nodules. The present study shows as supposed by previous studies on cell kinetics in PDL that subpopulations with larger growth potential were generally located in the middle portion of PDL and those with higher mineralization activities toward the surface of the roots. It is suggested, however, that a possible pathway of PDL cell turnover may exist within the PDL-SP on the root surface in addition to the generally recognized pathway from the middle area of PDL to root surface.

The clinical significance of cerebrospinal fluid lipid peroxides in central nervous system disease

Forty-four dogs were referred to our hospital presenting with neurological symptoms such as seizure or paraparesis. Magnetic resonance imaging (MRI) revealed abnormal results in 21 (abnormal MRI group) and normal results in 23 dogs (normal MRI group). Cerebrospinal fluid (CSF) (normal MRI group, n = 22; abnormal MRI group, n = 21) and serum lipid peroxide (LP) concentrations (normal MRI group, n = 11; abnormal MRI group, n = 15) were measured in a number of these dogs, and revealed a significant difference in the CSF/serum LP values (normal MRI group, n = 10; abnormal MRI group, n = 14) between the abnormal and the normal MRI groups (t-test and Mann-Whitney U-test p < 0.05). No other significant differences were observed. CSF/serum LP values exceeding 1.0 were exhibited in 10 of 14 dogs (71%) in the abnormal MRI group, and in 1 of 10 dogs (10%) in the normal MRI group. In the remaining animals, 4 dogs of the abnormal MRI group showed CSF/serum values lower than 1.0, 3 dogs had morphological abnormalities but no abnormal MRI signals in the central nervous system, and 1 dog had an abnormal MRI signal but no pathological abnormality. In the CSF analysis, 3 of 16 dogs (19%) of the abnormal MRI groupshowed abnormal cell counts and/or protein content. We conclude that the CSF/serum LP value can be used for the detection of neurological lesions such as oedema, inflammation and tumour.

Three-dimensional dynamic hip contact area and pressure distribution during activities of daily living

Estimation of the hip joint contact area and pressure distribution during activities of daily living is important in predicting joint degeneration mechanism, prosthetic implant wear, providing biomechanical rationales for preoperative planning and postoperative rehabilitation. These biomechanical data were estimated utilizing a generic hip model, the Discrete Element Analysis technique, and the in vivo hip joint contact force data. The three-dimensional joint potential contact area was obtained from the anteroposterior radiograph of a subject and the actual joint contact area and pressure distribution in eight activities of daily living were calculated. During fast, normal, and slow walking, the peak pressure of moderate magnitude was located at the lateral roof of the acetabulum during mid-stance. In standing up and sitting down, and during knee bending, the peak pressures were located at the edge of the posterior horn and the magnitude of the peak pressure during sitting down was 2.8 times that of normal walking. The peak pressure was found at the lateral roof in climbing up stairs which was higher than that in going down stairs. These results can be used to rationalize rehabilitation protocols, functional restrictions after complex acetabular reconstructions, and prosthetic component wear and fatigue test set up. The same model and analysis can provide further insight to soft tissue loading and pathology such as labral injury. When the pressure distribution on the acetabulum is inverted onto the femoral head, prediction of subchondral bone collapse associated with avascular necrosis can be achieved with improved accuracy.

Prenatal diagnosis of fetal hydrometrocolpos secondary to a cloacal anomaly by magnetic resonance imaging

Fetal female urogenital anomalies are often difficult to evaluate by ultrasonography, especially in late gestation. We report a case of fetal hydrometrocolpos detected at 35 weeks of gestation. Ultrasonography revealed a large retrovesical septate hypoechogenic mass in the fetal abdomen, however the sonographic findings were inconclusive. Magnetic resonance imaging (MRI) confirmed that the abdominal mass was fluid-filled with a mid-plane septum in the midline posterior to the bladder, and showed a connection to the dilated uterus that was duplicated. These findings were consistent with a diagnosis of hydrometrocolpos with septate vagina and uterus didelphys. The neonate showed abdominal distension, ambiguous genitalia and anal atresia with a single perineal opening. Hydrometrocolpos was secondary to a urethral type of cloacal anomaly. Aspiration of the mass and a colostomy were performed on the first postnatal day, followed by anorectoplasty at 19 months of age. MRI is a useful complementary tool for assessing fetal urogenital anomalies when ultrasonography is inconclusive.

Low-dose levodopa therapy in Japanese patients with Parkinson's disease: a retrospective study

OBJECTIVE

To investigate the efficacy and the rate of adverse events of chronic low-dose levodopa-carbidopa therapy in Japanese patients with Parkinson's disease (PD).

PATIENTS AND METHODS

A total of 92 Japanese PD patients treated with low doses of levodopa from the outset were studied. Both disease-specific motor disabilities and quality of life (QOL) in the patients were evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS) and the Parkinson's Disease 39 Quality of Life Questionnaire (PDQ39), respectively.

RESULTS

In the overall patient group, the mean duration of treatment, the mean daily dose of levodopa, the disability scores and the motor scores of UPDRS were 6.2 years, 186.4 mg, 8.0 and 19.2, respectively. The rates of motor fluctuations, dyskinesias and hallucinations were 8.7%, 6.5% and 14.1%, respectively. The mean summary index of PDQ39 scores was 23.1. Patients with motor fluctuations showed a significantly earlier disease onset. Dose of levodopa, age at onset, and treatment duration were not associated with the occurrence of dyskinesias. Patients with hallucination had higher doses of levodopa and dopamine agonist.

CONCLUSIONS

Our results demonstrate that chronic administration of a low-dose levodopa preparation can provide satisfactory benefit with a low incidence of motor complications, and can result in good QOL in Japanese patients with PD. The concomitant use of a small amount of dopamine agonist and amantadine from the outset has partly contributed to a reduced dose of levodopa and the lesser occurrence of motor complications.

[Current situation and future of gastric cancer screening examinations: from the viewpoint of gastric X-ray screening]

In Japan, screening examinations for gastric cancer have been conducted for 50 years because of the high prevalence of this type of cancer. Gastric X-ray screening examinations have contributed to the detection early gastric cancer. In 2001, Hisamichi et al. reported that X-ray examination is a valid technique in gastric cancer screening. However, they indicated that problems in the uncertainty of accuracy and the risk of radiation exposure at a young age. On the other hand, endoscopic screening examination, pepsinogen-method and H. pylori method are not acceptable because of incident risk. Our future goals are to improve the precision of gastric X-ray examinations in cancer screening nationwide and to advocate for annual gastric screening examinations in higher risk groups. As a result, it is hoped that gastric cancer X-ray screening examinations can contribute to preventive medicine.

Subdural accumulation of fluid in a dog after the insertion of a ventriculoperitoneal shunt

A dog with hydrocephalus as a result of aqueduct stenosis and cerebellar herniation underwent ventriculoperitoneal shunting. Magnetic resonance images and computed tomography scans taken after the surgery revealed subdural accumulations of haemorrhagic fluid and cereberocortical collapse caused by overshunting and leakage of cerebrospinal fluid from the site of insertion of the shunt. However, the degree of cerebellar herniation was reduced after the shunt was inserted, and the dog did not develop any neurological signs and made good progress.

Cytological basis for enhancement of radiation-induced mortality by Friend leukaemia virus infection

PURPOSE

To analyse the cytological basis for enhancement of radiation-induced mortality by Friend leukaemia virus infection.

MATERIALS AND METHODS

Cellularity in haematopoietic tissues of C3H mice infected with FLV and/or whole-body irradiation was examined.

RESULTS

When mice were treated with a sublethal dose (3 Gy) of irradiation at 1 week after virus infection, most manifested a severe loss of cellularity in the spleen, bone marrow and peripheral blood 2 weeks after irradiation. More than 90% of the mice died within 1 month post-irradiation. However, this deleterious effect of virus infection on the survival of irradiated mice was observed only when they were irradiated at around 1 week after virus inoculation. Strain differences in the sensitivity to this effect were observed among virus-sensitive strains of mice.

CONCLUSIONS

The results indicate that Friend leukaemia virus infection can cause enhancement of radiation sensitivity of haematopoietic cells in host animals in a restricted manner in terms of genetic background and the interval between infection and irradiation.

Determination of di(2-ethylhexyl)phthalate and mono(2-ethylhexyl)phthalate in human serum using liquid chromatography-tandem mass spectrometry

Concentrations of mono(2-ethylhexyl)phthalate (MEHP), and di(2-ethylhexyl)phthalate (DEHP), in serum of healthy volunteers were determined by high performance liquid chromatography (HPLC) with tandem mass spectrometry (LC/MS/MS). The serum was extracted with acetone, followed by hexane extraction under acidic conditions, and then applied to the LC/MS/MS. Recoveries of 20 ng/ml of MEHP and DEHP were 101+/-5.7 (n=6) and 102+/-6.5% (n=6), respectively. The limits of quantification (LOQ) of MEHP and DEHP in the method were 5.0 and 14.0 ng/ml, respectively. The concentration of MEHP in the serum was at or less than the LOQ. The concentration of DEHP in the serum was less than the LOQ. Contaminations of MEHP and DEHP from experimental reagents, apparatus and air during the procedure were less than the LOQ and were estimated to be <1.0 and 2.2+/-0.6 ng/ml, respectively. After subtraction of the contamination, the net concentrations of MEHP and DEHP in the serum were estimated at or <5 and <2 ng/ml, respectively. To decrease contamination by DEHP, the cleanup steps and the apparatus and solvent usage were minimized in the sample preparation procedures. The high selectivity of LC/MS/MS is the key for obtaining reliable experimental data from in the matrix-rich analytical samples and for maintaining a low level contamination of MEHP and DEHP in this experimental system. This method would be a useful tool for the detection of MEHP and DEHP in serum.

Expression of IAP family proteins in colon cancers from patients with different age groups

Members of the inhibitor of apoptosis protein (IAP) family including survivin, are expressed in many tumors. However, age-related changes in their expression in cancer have not been clarified. Thus, we investigated the expression of mRNA-coding for IAP family proteins in colon cancer samples from young (<70 years of age) and elderly (>70 years) patients by real-time quantitative RT-PCR. Samples were collected from cases with well-differentiated adenocarcinoma or moderately differentiated adenocarcinoma and their adjacent normal epithelial tissue. Well-differentiated adenocarcinoma tended to express higher levels of survivin than normal mucosa, and expression in moderately differentiated adenocarcinoma was significantly greater than in normal mucosa in samples from both groups of patients ( p<0.05, respectively). When samples were compared between the different age groups, the normal mucosa exhibited similar levels of survivin expression. However, samples from older patients showed a significantly higher level of expression than those from younger patients in well and moderately differentiated adenocarcinomas ( p<0.05, respectively). In contrast, the levels of expression of cIAP1, cIAP2, and NAIP in the cancerous tissues were lower than those found in normal mucosa regardless of age. As for age-related changes, the expression of cIAP2 in normal mucosa and moderately differentiated adenocarcinoma was stronger in the elderly group than the young group ( p<0.05, respectively), and NAIP expression in well-differentiated adenocarcinoma was higher in the young group than the elderly group ( p<0.05). XIAP expression was similar in normal and cancerous tissues in both the young and elderly groups. These results suggest that the expression of IAP family proteins, especially survivin, is associated with the age-related biological characteristics of colon cancer.

Cerebellar Focal Granulomatous Meningoencephalitis in a Dog: Clinical Findings and MR Imaging

The authors encountered a dachshund dog, presenting vestibular disorder. On magnetic resonance (MR) imaging, a mass showing isointensity on the T1- and T2-weighted images and enhanced by contrast medium, was observed in the right cerebellum. In addition, the periphery of the mass showed isointensity on the T1-weighted image and hyperintensity on the T2-weighted image, suggesting sever oedema. Although the dog underwent surgery, it died. The mass was diagnosed pathologically as a granulomatous meningoencephalitis.

Electrical stimulation of the posterior subthalamic area for the treatment of intractable proximal tremor

OBJECT

Tremors, including its proximal component, are often refractory to standard thalamic surgery. In the 1960s the posterior part of the subthalamic white matter was reported to be a promising target in treating various forms of tremor, but was also found to be associated with adverse effects. Advances involving a less invasive method, that is, deep brain stimulation (DBS), has led to a reappraisal of this target.

METHODS

Eight patients with severe essential tremor involving the proximal arm were treated using unilateral stimulation of the posterior part of the subthalamic white matter. The tentative target was situated in the area lateral to the red nucleus and posteromedial to the subthalamic nucleus. Macrostimulation was used to find the optimal site to suppress tremor. Through a quadripolar DBS lead, somatosensory evoked potentials (SSEPs) were recorded. Improvement of tremor was evaluated based on a modified clinical tremor rating scale. Anatomical locations of all contacts were assessed using stereotactic guidance and represented on the Schaltenbrand-Wahren atlas.

CONCLUSIONS

A characteristic diphasic pattern of SSEPs reaffirmed the electrophysiological endorsement of this target. Tremors, both proximal and distal, were remarkably improved in all patients. The rate of improvement, as indicated by the total tremor score, was a mean of 81%. Axial tremors in the legs and head were also improved. Most of the contacts associated with remarkable improvement were located in the posterior part of the subthalamic white matter (the zona incerta and prelemniscal radiation). Neither major complications nor neurological deterioration was observed. The authors concluded that DBS of the posterior part of the subthalamic white matter together with SSEP recording is a safe and effective method to ameliorate severe intractable tremors.

In vivo distribution of receptor for ecotropic murine leukemia virus and binding of envelope protein of Friend Murine leukemia virus

Ecotropic infection by Murine leukemia virus (MuLV) infection is initiated by the interaction between the receptor-binding domain of the viral surface glycoprotein (SU) and the cell-surface receptor, mCAT-1. To study the in vivo localization of viral binding site in mice, green fluorescence protein (GFP)-tagged Friend SU (F-SU/GFP) was incubated with tissue sections. Lymphohematopoietic organs and a part of the glandular tissues of C3H as well as C57BL/6 mice revealed positive signals for F-SU/GFP binding on the cell surface. In contrast, C4W mice, which is a partial congenic mouse strain carrying the Fv-4 (r) gene on a BALB/c genetic background, exhibited negative signals in most of the organs except for a very weak binding in the pancreas. The expression of mCAT-1 mRNA determined by reverse transcriptase (RT)-polymerase chain reaction (PCR) revealed a similar distribution in C3H, C57BL/6 and C4W mice. Most of the organs including lymphohematopoietic organs and glandular organs revealed significant expression of mRNA for mCAT-1 gene, while the liver, heart and muscle did not. The results from binding assay were consistent with the fact that Friend MuLV-induced pathogenesis was usually associated with lymphohematopoietic systems, although mRNA expression for mCAT-1 was rather ubiquitous. The discrepancy between F-SU/GFP binding and mRNA expression for mCAT-1 in lymphohematopoietic organs of C4W mice would support the receptor interference effect by the Fv-4 (r) gene causing the resistance of C4W mouse to Friend MuLV infection.