Nitric oxide relaxes bovine ciliary muscle contracted by carbachol through elevation of cyclic GMP

It is generally accepted that nitric oxide relaxes vascular smooth muscles by activating guanylyl cyclase, which in turn increases cyclic 3':5' guanosine monophosphate level. Despite the physiological significance of nitric oxide, very few studies have attempted to characterize the mode of action of this mediator in ciliary muscles. Therefore, the present experiments were designed to investigate whether or not the relaxation induced by sodium nitroprusside as a donor of nitric oxide is accompanied by the increase in cyclic 3':5' guanosine monophosphate level in the bovine ciliary muscle, and these responses are affected by methylene blue as an inhibitor of guanylyl cyclase and 3-isobutyl-1-methylxanthine as an inhibitor of phosphodiesterases. The relaxation activity of exogenous 8-bromo-cyclic 3':5' guanosine monophosphate was also determined. Sodium nitroprusside produced a concentration-dependent relaxation in the bovine ciliary muscle strips which had been contracted by carbachol as a cholinergic agonist. Relaxation in response to sodium nitroprusside was accompanied by a significant (P<0.05 and P<0.005) increase in cyclic 3':5' guanosine monophosphate level. The relaxation response and the increase in cyclic 3':5' guanosine monophosphate caused by sodium nitroprusside were significantly (P<0.01 and P<0.05) augmented by the pretreatment with 3-isobutyl-1-methylxanthine, and were significantly (P<0.005 and P<0.05) attenuated in the presence of methylene blue. The exogenously applied 8-bromo-cyclic 3':5' guanosine monophosphate relaxed the ciliary muscle strips in a concentration-dependent manner. These results suggest that nitric oxide causes relaxation of the bovine ciliary muscle through the activation of guanylyl cyclase and an increase in cyclic 3':5' guanosine monophosphate level.

Uptake of Rhodnius heme-binding protein (RHBP) by the ovary of Rhodnius prolixus

The uptake of RHBP (Rhodnius heme-binding protein) by the ovaries of Rhodnius prolixus was characterized. RHBP purified from occyte was labeled with 125I and used to study the process of uptake by the ovary in vivo and in vitro. After injection, the [125I]RHBP was readily removed from the hemolymph and accumulated especially in the ovary. The capacity of the ovary to take up [125I]RHBP from the hemolymph varied during the days following blood meal. It increased up to day 2, remained stable until day 5, and then decreased up to the end of oogenesis. In vitro, the uptake of [125I]RHBP was linear at least up to 60 min. The uptake was dependent on [125I]RHBP concentration and showed to be a saturable process. The addition of a molar excess of non-related proteins such as Vitellin (Vt), Lipophorin (Lp), and Bovine Serum Albumin (BSA) did not reduce [125I]RHBP uptake. Using immunogold technique the RHBP was localized at the microvilli, coated pits, and yolk granules. The main yolk protein, Vt, did not compete with RHBP for the uptake. Thus, it is discussed here that they bind to independent binding sites of the oocytes, and are directed later on to the same compartment. The need of both proteins for the completion of mature oocyte was verified in vivo. The reduction of heme-RHBP in the hemolymph, by changing the diet, decreased the number of eggs laid. Increasing the concentration of heme-RHBP in the hemolymph, the number of eggs produced increased in a dose dependent manner. In vitro, both apo-RHBP and heme-RHBP can be taken up by the oocyte. Since the mature oocyte contains only heme-saturated RHBP, the possible fate of apo-RHBP is also discussed.

Usage of T cell receptor (TCR) V beta gene in ulcerative colitis

Ulcerative colitis (UC) is an inflammatory disease of unknown etiology. In this study, the expression of TCRV beta gene in UC patients was examined. The present study included 11 consecutive Japanese patients with UC. The control group comprised 10 healthy people. The usage of T Cell Receptor (TCR) V beta chain gene segments in peripheral blood was examined using RT-PCR. In addition, HLA-DR DNA typing was performed for the 11 patients with UC. The average of the positive expression rates in the UC group was 0.617 +/- 0.126, which was significantly higher than that of the control group (0.829 +/- 0.080) (p < 0.01). In the UC group, the usage of V beta chain gene in the active phase was almost same as that in the inactive phase. No specific distribution of V beta repertoire was observed in the UC group. In UC patients, no distinct correlation was found between any certain HLA-DR type and TCRV B gene usage. UC patients had a significantly lower rate of the expression of TCR V beta genes compared to normal controls. There is a possibility that the restricted usage of TCR V beta repertoire is possibly related to the existence of oligoclonal TCR repertoire in UC patients.

[A clinicopathological study of 218 patients with bladder carcinoma treated by radical cystectomy]

Between 1986 and 1995, 218 patients with primary carcinoma of the bladder were treated with radical cystectomy at our hospitals. Clinicopathological specimens and the relative value of prognostic factors were analyzed with both the univariate and multivariate method. Univariate analysis indicated that age, sex, pathological tumor stage, grade, vessel involvement, tumor infiltrating type and positive nodes were predictive of poor cancer-specific survival. Multivariate analysis demonstrated that female patients were predictive of poor cancer-specific survival. As for the risk ratio, the prognostic factors in lymphatics involvement and tumor infiltrating type were 2.77 and 2.47, respectively.

Effects of growth hormone-releasing hormone (GRF) analogs, bovine and rat GRF on growth hormone secretion in cattle in vivo

Effects of bovine and human growth hormone-releasing hormone (GRF) analogs (bGRF(1-29)-NH2: bGRF-29, [D-Ala2, Ala15]-bGRF-29, [D-Ala2]-hGRF(1-29)-NH2: [D-Ala2]-hGRF-29), bovine GRF (bGRF(1-44)-NH2: bGRF-44), as well as rat GRF (rGRF) on GH release were studied in female calves. Intravenous (i.v.) bolus injections of 0.25 microg/kg BW of bGRF-29, [D-Ala2, Ala15]-bGRF-29, and [D-Ala2]-hGRF-29 stimulated GH release. Plasma GH levels began to rise 10 min after the injection of each peptide, and significant increases in GH concentrations were obtained at 60, 180 and 150 min after the injection of bGRF-29, [D-Ala2, Ala15]-bGRF-29 and [D-Ala2]-hGRF-29, respectively. The concentrations of GH 80 min after the injection of [D-Ala2, Ala15]-bGRF-29 were significantly higher than those after the injection of [D-Ala2]-hGRF-29 (except at 80 and 90 min) or bGRF-29. The i.v. bolus injections of 0.25 microg/kg BW of bGRF-44 and rGRF stimulated GH release, and the GH-releasing potency of rGRF was approximately equal to that of bGRF-44. The plasma GH responses to the repeated i.v. injection of bGRF-29 or [D-Ala2, Ala15]-bGRF-29 at 2-h intervals were examined. bGRF-29 acutely increased plasma GH levels after each injection, and the high GH levels decreased to the basal values within 2 h. In contrast, high GH levels induced by [D-Ala2, Ala15]-bGRF-29 were gradually decreased but not lowered to basal values throughout the experiment. These results show that [D-Ala2, Ala15]-bGRF-29 has longer-lasting and greater GH-releasing activity than the other GRF analogs in female calves, and the GH-releasing potency of rat GRF is approximately equal to that of bovine GRF in cattle in vivo.

Nitric oxide-induced ciliary muscle relaxation during contraction with endothelin-1 is mediated through elevation of cyclic GMP

PURPOSE

Nitric oxide (NO) relaxes ciliary smooth muscle, and endothelin-1 (ET-1) is reported to regulate ciliary muscle tone. Despite the physiological significance of nitric oxide and ET-1, very few studies have attempted to characterize the mutual modes of action of these mediators in this tissue. Thus, the present experiments were designed to investigate a possible relaxation mechanism of nitric oxide in bovine ciliary muscle that has been contracted by ET-1.

METHODS

The effects of sodium nitroprusside (SNP), as a nitric oxide donor, methylene blue, as an inhibitor of guanylate cyclase, and 8-bromo-cyclic GMP on the bovine ciliary muscle contracted with ET-1 were examined. The changes in cyclic GMP level and relaxation, in response to SNP alone or in combination with 3-isobutyl-1-methylxanthine (IBMX) as a nonselective inhibitor of phosphodiesterases, were also determined.

RESULTS

Sodium nitroprusside (SNP) produced a concentration-dependent relaxation, which was significantly (p < 0.005) augmented by 10(-5) M 3-isobutyl-1-methylxanthine (IBMX) and significantly (p < 0.005) attenuated by 3 x 10(-5) M methylene blue as an inhibitor of guanylate cyclase. The relaxation in response to SNP was accompanied by an increase in the cyclic 3':5' guanosine monophosphate (cyclic GMP) level, which was again significantly (p < 0.05) augmented by 10(-5) M IBMX and significantly (p < 0.005) attenuated by 3 x 10(-5) M methylene blue. The exogenously applied 8-bromo-cyclic GMP relaxed the ciliary muscle strips during the contraction caused by ET-1.

CONCLUSIONS

These results lead us to assume that NO generated from SNP is closely related to cyclic GMP production via the activation of guanylate cyclase and, in turn, causes a relaxation response in the bovine ciliary muscle contracted with ET-1.

A localized fibrous tumor (mesothelioma) in the mediastinum: report of a case

We report herein the rare case of a 51-year-old Japanese woman who underwent thoracotomy for a mass in the mediastinum which was found to be a benign localized fibrous tumor, otherwise known as a mesothelioma. The clinical behavior of this tumor is thought to be unpredictable, and therefore we emphasize that long-term follow-up of patients with localized fibrous tumors is necessary, even if the histological features are benign.

Loss of arterial dilation in the reendothelialized area of the flow-loaded rat common carotid artery

We have investigated regenerated endothelial cells and their possible contribution to arterial dilation in response to increased blood flow in rat common carotid artery (CCA). After endothelial denudation using a balloon catheter in the left CCA, an arteriovenous shunt was constructed between the left CCA and the left external jugular vein at 20 mm distal from the orifice in the denuded group. Animals that were given the arteriovenous shunt without denudation were used to form the nondenuded group. The blood flow rate in the left CCA was increased by sixfold after operation in the denuded group. We observed that endothelial cells were gradually regenerated from the orifice to the distal area and that the reendothelialized area after 4 to 8 weeks was approximately one third of the left CCA (5.31 +/- 1.49 mm at 4 weeks, 5.47 +/- 1.56 mm at 8 weeks). In the reendothelialized area of the left CCA after 4 to 8 weeks, the lumen diameter was significantly smaller than that of the nondenuded group and showed no significant difference from age-matched nonsurgical animals. The intimal and medial thickening, which would result in arterial stenosis in the reendothelialized area, was not observed in the denuded group, although the denuded control showed significant intimal thickening. From these results, we conclude that regenerated endothelial cells reduce intimal thickening but do not respond to increased blood flow to dilate the artery.

[Composite valve graft replacement in patients with type A aortic dissection--a modified cabrol procedure]

Composite valve graft replacement of the ascending aorta and aortic valve is indicated for a variety of conditions affecting the aortic root. However, a major drawback in this operation is bleeding from the proximal suture line and coronary anastomosis especially in patient with friable root tissue involved by aortic dissection. We describe here a modified technique to take advantage of the aortic button and cabrol techniques to reattach the coronary artery ostia. We have experienced seven patients with the aortic root replacements for type A dissection using the described technique over the past two years. In view of our favorable experience, we recommend this technique especially for patient with acute dissection involving nondilated aortic annulus, in addition to the patients with Marfan syndrome or annulo-aortic ectasia.

Bone mass loss due to estrogen deficiency is compensated in transgenic mice overexpressing human osteoblast stimulating factor-1

Osteoblast stimulating factor-1 (OSF-1) stimulates in vitro proliferation and differentiation of osteoblastic cells, and its gene is expressed in the bone and brain tissues in mammals and amphibians. To evaluate the in vivo function of OSF-1 in bone metabolism, transgenic mice overexpressing the human osf-1 gene driven by the osteocalcin promoter were generated. Femoral bone mineral content was increased in transgenic mice relative to wild-type controls as estimated by ash assay, depending on the transgene copy number per cell. In ovariectomized mice, bone mass loss due to estrogen deficiency was observed in both transgenic and control mice but bone mass was still higher in transgenic mice than in controls. Bone mass in ovariectomized transgenic mice was comparable to that in wild-type mice without ovariectomy. These observations indicate that OSF-1 may direct in vivo appositional bone formation by increasing osteoblast activity rather than decreasing osteoclast activity, suggesting a new way to treat osteoporosis with OSF-1.

Role of phospholipids in the protein stability of an insect lipoprotein, lipophorin from Rhodnius prolixus

Lipophorin (Lp) is the major lipoprotein in insect hemolymph. The structural organization proposed for Lp is basically the same as that suggested for vertebrate lipoproteins, consisting of a hydrophobic core containing neutral lipids, stabilized in the aqueous environment by surrounding polar moieties of protein and phospholipids at the particle surface. After complete removal of phospholipids from Lp by phospholipase A2, the particle remains soluble [Gondim, K. C., Atella, G. C., Kawooya, J. K., & Masuda, H. (1992) Arch. Insect Biochem. Physiol. 20, 303-314]. However, studies on the roles of phospholipid on the structural stability of Lp are still lacking. In the present work, we have studied the structure and stability of dephospholipidated lipophorin (d-Lp). Trypsinolysis of d-Lp indicated no exposure of new cleavage sites on the protein when compared to Lp. However, an enhanced rate of proteolysis of the apoproteins (especially apolipophorin II) was observed in d-Lp. Circular dichroism analysis indicated that the secondary structure of Lp was not significantly affected by phospholipid removal. Furthermore, the exposure of tryptophan residues to the aqueous solvent in d-Lp was the same as in Lp, as indicated by intrinsic fluorescence emission spectra and fluorescence quenching experiments. Interestingly, d-Lp was more resistant to denaturation by guanidine hydrochloride than Lp. d-Lp was also found to be less sensitive than Lp to structural changes induced by hydrostatic pressure. Taken together, these results indicate that, although changes in its structural organization were subtle, dephospholipidated lipophorin may have additional protein-protein and/or protein-neutral lipid interactions that are responsible for the observed increase in stability. Therefore, phospholipids are not only not essential for Lp stability, but their presence in the particle seems to result in a less stable structure in the aqueous environment.

Cerebellar myeloblastoma formation in CD7-positive, neural cell adhesion molecule (CD56)-positive acute myelogenous leukemia (M1)

We present a first report of a CD7+ acute myelogenous leukemia patient who developed intracranial myeloblastomas. The patient was neurologically normal on physical examination at presentation. The peripheral leukocyte count was extremely high (203.6 x 10(9)/l). The blasts expressed CD7 and CD56 (neural cell adhesion molecule) in addition to CD13, CD33, CD34, and HLA-DR. The karyotype of bone marrow cells was normal. The patient was diagnosed as having acute myelogenous leukemia (AML, M1). Following a short period of complete remission, bone marrow relapse and meningeal leukemia occurred, and the patient died of respiratory failure. Autopsy revealed that blasts had invaded the subarachnoid space and cerebellum, and two myeloblastomas were found in the cerebellar hemisphere. Both CD7+ and CD56+ AML have been reported to have a high incidence of central nervous system involvement. CD7+ CD56+ AML calls for prophylaxis of central nervous system leukemia.

Non-lethal junctional epidermolysis bullosa in a dog

We report a 4-year-old female mongrel dog with a history since birth of erosions and atrophic skin, with pigmentation and alopecia on the face, trunk and extremities, together with dystrophic nails. Light microscopy revealed subepidermal blisters with minimal inflammation and electron microscopy confirmed that the ultrastructural site of separation site was at the lamina lucida. Indirect immunofluorescence of the dog's skin detected the positive expression of laminin 5, BPAG2, integrin-alpha 6 and type VII collagen. These clinical, ultrastructural and immunohistochemical features suggested that the dog had a non-lethal subtype of junctional epidermolysis bullosa (JEB). This is the first confirmed case of non-lethal JEB in a dog and presents a possible candidate for an animal model of gene therapy. Further study should provide important information of the phenotype, pathophysiology and prognosis of non-lethal JEB in humans.

[Advances in clinical laboratory tests for diabetes mellitus]

Advances in clinical laboratory tests for diabetes mellitus have been reported. 1) Examinations for diagnosis of diabetes mellitus: Assay of autoantibody to glutamic acid decarboxylase was commercially developed recently. This is useful for distinguishing insulin-dependent diabetes mellitus (IDDM) from non-autoimmune diabetes and for predicting the prognosis in IDDM. 2) Examinations for assessment of glycemic control: New methods of assessing glycemic control in patients with diabetes mellitus (glycated albumin, 1,5-anhydroglucitol) have been developed. It is important to be familiar with the characteristics of each test and to use each one properly. Because of the large interlaboratory difference in glycohemoglobin (GHb) measurement has been an issue of greatest importance, standardization of GHb measurement was required. To reduce this difference, it is recommended to remove unstable GHb and to correct the value using the JDS GHb standard. Currently, the difference has been reduced to a clinically permissible level (the fourth report of the GHb standardization committee). 3) Examinations for chronic complications in diabetes: Disturbances of the central nervous system may occur as diabetic neuropathy in patients with diabetes mellitus. Progress in thermology has revealed latent aortic occlusive disease in the legs and autonomic disturbance that lead to abnormal vascular responses. 4) Examinations for self-monitoring of blood glucose: The technology used for noninvasive blood glucose monitoring involves either radiation or fluid extraction. Each method has features predicting commercial viability.

Autoregulation of portal circulation: a correlative study of circulation and vascular morphology

To investigate the mechanism of portal circulation and the genesis of portal hypertension, an in vivo model was made to increase portal venous flow (PVF) by forming a bypass shunt between the femoral artery to the splenic venous branch in pigs and dogs via a regulatable pump. Using this model, an autoregulatory hemodynamics of the portal circulation and corresponding morphological changes of the intrahepatic vascular system were determined. Immediately after blood flow increase (100 mL/min) to the portal vein, PVF increased to the baseline level plus bypass shunt flow. But, PVF returned to the baseline level within 1 h for both animals. Portal venous resistance (PVR) at 1 h was significantly higher than the baseline level (P < 0.05). By histometric analysis of the cross-sectional area of the portal and hepatic venous branches (CSA-PV, CSA-HV) using the biopsized liver, CSA-HV at 1 h was 27.6% of the CSA-HV of the baseline level in dog, which showed narrowing and contractive changes of the hepatic venous branches, and CSA-PV at 1 h was 36.4% of the CSA-PV of the baseline level in pig, which showed narrowing and contractive changes of the portal venous branches. It is suggested that a tone of the intrahepatic vascular system has an important role in the portal autoregulatory hemodynamics.

Disseminated intra-abdominal cystic lymphangiomatosis with severe intestinal bleeding. A case report

We describe cystic lymphangiomatosis with intestinal bleeding developing multiple lymphangiomas in the small intestine, mesentery, mesocolon, omentum, retroperitoneum, and spleen. Small intestinal fluorography showed multiple polypoid lesions, mainly in the jejunum. Ultrasonography, computed tomography, and magnetic resonance imaging showed diffuse cystic tumors in the mesentery and spleen. Cystic lymphangiomatosis was proved by histologic findings of the biopsied specimen at laparotomy.

Predictive value of serum immunosuppressive acidic protein for staging renal cell carcinoma: comparison with other tumour markers

OBJECTIVE

To examine the usefulness of serum immuno-suppressive acidic protein (IAP) as a predictor for staging renal cell carcinoma (RCC), using receiver-operator characteristic (ROC) analysis, and to compare IAP with other tumour markers.

PATIENTS AND METHODS

From September 1983 to December 1995, serum IAP was measured in 133 untreated patients with RCC (mean age 60.1 years, SD 11.4. range 31-84). The erythrocyte sedimentation rate (ESR), the levels of fibrinogen, C-reactive protein (CRP), and alpha 2-globulin were also measured. To compare these markers as predictors of local involvement of the renal capsule, lymph node and distant metastasis, the area under the corresponding ROC curve was calculated. Tumour size at the time of resection was added in this analysis for comparison with the levels of these tumour markers.

RESULTS

The final pathological stage was T1 or T2 in 101 patients and T3 or T4 in 32, while it was N0 in 122 patients, N1-3 in seven, M0 in 114 patients and M1 in 19. The area of the ROC curve for tumour size was greatest (0.843) for staging of the local extent (T1/T2 versus T3/T4) and that for IAP was 0.714, similar to the values for fibrinogen, ESR and CRP. For predicting lymph node metastasis, IAP and fibrinogen were the most important (0.864). However, IAP alone (0.894) was the most important predictor of distant metastasis. Using an IAP threshold of 600 micrograms/mL gave a high sensitivity and specificity for detecting lymph node and distant metastasis.

CONCLUSION

IAP is a valuable predictor of lymph node and distant metastasis in patients with RCC, although it is inferior to tumour size in predicting local involvement of the renal capsule. The appropriate threshold value of IAP for detecting lymph node and distant metastasis is 600 micrograms/mL.

Transition zone ratio and prostate-specific antigen density as predictors of the response of benign prostatic hypertrophy to alpha blocker and anti-androgen therapy

OBJECTIVE

To determine whether transrectal ultrasonography (TRUS) can predict the clinical response of patients with benign prostatic hypertrophy (BPH) to alpha 1-blocker and anti-androgen therapy.

PATIENTS AND METHODS

From April 1994 to July 1995, 128 patients with BPH were randomized to treatment for 6 months with either tamsulosin (a long-acting selective alpha 1-blocker) or allylestrenol (an anti-androgen), with 64 patients receiving tamsulosin (0.2 mg/day) and 64 receiving allylestrenol (50 mg/day). The results of TRUS, uroflowmetry and the American Urologic Association (AUA) symptom score were compared before and after treatment. TRUS was used to calculate the transition zone (TZ) volume, transition zone ratio (TZ ratio = TZ volume/total prostate volume), total prostate volume and prostate-specific antigen density (PSAD).

RESULTS

Both groups showed a statistically significant improvement in the AUA symptom score, quality-of-life (QOL) score and peak urinary flow rate (Qmax) at 6 months (P < 0.001). In the tamsulosin group, there was a significant negative correlation between the pretreatment PSAD and the percentage change in Qmax (r = -0.640, P < 0.001), while there was a positive correlation between PSAD and the percentage change in the AUA symptom score (r = 0.589, P < 0.001). On the other hand, the allylestrenol group showed a significant positive correlation between PSAD and the percentage change in Qmax (r = 0.397, P < 0.01) and a negative correlation between PSAD and the AUA symptom score (r = -0.313, P < 0.01).

CONCLUSION

Patients with a high pretreatment PSAD responded well to anti-androgen therapy, while those with a low PSAD responded better to alpha 1-blocker therapy.

[Cerebral cytochrome oxidase monitoring by near infrared spectroscopy during selective cerebral perfusion]

To evaluate selective cerebral perfusion (SCP) for brain protection, the redox state of cytochrome oxidase (Cyt. aa3) in brain tissue were studied in 27 patients with thoracic aortic repair. The redox state of Cyt. aa3 was monitored by near infrared spectroscopy (NIRS) (OM-110, Shimazu). There were no significant changes in the Cyt. aa3 redox state in 13 (Group I), the oxidation state of Cyt. aa3 decreased then recovered to control levels in 12 (Group II), and the oxidation state decreased but did not recover in 2 patients (Group III). Postoperative cerebral damage was observed in 5 patients; blindness occurred in one patient in Group I (8.3%), 2 patients developed hemiplegia in Group II (15.4%), and the 2 patients in Group III failed to reawaken (100%). The incidence of cerebral damage was significantly higher in Group III than in Groups I and II (p < 0.05). We conclude that monitoring the redox state of Cyt. aa3 using NIRS is useful in predicting postoperative cerebral damage. However, it is necessary to increase the number of measurement sites since NIRS can reflect the state in only a small area of the brain.

Liver metastasis rare in colorectal cancer patients with fatty liver

BACKGROUND/AIMS

As no reports in terms of the relationship between fatty liver and liver metastasis of colorectal cancer clinicopathological analysis of colorectal cancer patients with fatty were found a liver was carried out.

PATIENTS AND METHODS

Among 839 patients with single colorectal carcinoma who underwent operations at our department between 1985 and 1994, 121 patients were designated as fatty liver using ultrasonography (FL group). The remaining 718 non-fatty liver patients with colorectal cancer (NFL group) were compared to the FL group regarding clinicopathological aspects.

RESULTS

(1) There were only two patients who had liver metastasis in the FL group (1.7%), while the NFL group included 115 patients with liver metastasis (16.0%) (p < 0.01). (2) The five-year survival rate of the FL group was 95.7%, which was significantly higher than that in the NFL group (9.8%) (p < 0.001). (3) In the multivariate analysis, the fatty liver was identified as an independent prognostic factor.

CONCLUSIONS

The FL group had a much better prognosis compared to the NFL group. Especially, liver metastasis was extremely rare in the FL group. We believe that these results will lead to the clarification of the liver metastasis mechanism.

Structure and expression of the human SM22alpha gene, assignment of the gene to chromosome 11, and repression of the promoter activity by cytosine DNA methylation

To investigate the molecular mechanisms that control expression of smooth muscle cell (SMC) differentiation genes, we have isolated the human SM22a gene, which is composed of five exons and four introns, spanning an approximately 6-kilobase (kb) genomic DNA at chromosome region 11q23.2. Expression of the SM22a messenger RNA was detected in serum-stimulated cell cultures including SMC, undifferentiated skeletal muscle-lineage cells, and fibroblasts, and it was down-regulated in SMC of balloon-injured atheromatous human vessels. A major transcription start site of the SM22alpha gene is located at 75 base-pairs (bp) upstream of the ATG start codon. Analysis of the 2.6 kb 5'-upstream sequence demonstrated that two CArG/SRF-boxes and two GC-box/Sp1-binding sites were present at bp -147 and -274, and at bp -233 and -1635, respectively. The nucleotide sequences of the two CArG/SRF-boxes and the proximal GC-box/Sp1 binding site are 100% conserved with those of the murine SM22alpha genes [Solway, J., Seltzer, J., Samaha, F.F., Kim, S., Alger, L.E., Niu, Q., Morriesey, E.E., Ip, H.S., and Parmacek, M.S. (1995) J. Biol. Chem. 270, 13460-13469; Kemp, P.R., Osbourn, J.K., Grainger, D.J., and Metcalf, C. (1995) Biochem. J. 310, 1037-1043]. Cell transfection assays using a luciferase reporter gene construct containing the 455-bp 5'-flanking region (positions -26 to -480) showed that methylation of the CpG dinucleotides within this segment reduces its transcriptional activity. The results imply a novel mechanism for transcriptional control of the SMC differentiation-specific gene promoter.