[Evaluation of preoperative chemotherapy for colorectal cancer]

Patients who underwent curative resection for colorectal cancer between January 1987 and June 1989 were divided into two groups, to assess the usefulness of preoperative chemotherapy (400 mg UFT therapy daily for 10 days more) and to analyze changes in the proliferative activity of tumor cells. Fifty-five cases were included in the study. Thirty-three had received no preoperative chemotherapy (Group A), and 22 had received the preoperative chemotherapy (group B). The five-year cumulative survival rate was 81.1% for group A and 90.2% for Group B. The proportion of patients with no recurrence was 75.7% in Group A and 85.7% in Group B. Both parameters thus tended to be better in patients who had received preoperative chemotherapy. When PCNA labeling before UFT therapy was compared with that after UFT therapy in 13 cases, the PCNA labeling rate decreased after UFT therapy in 9 (69%) of the 13 cases. These results suggest that preoperative chemotherapy using UFT is useful in treating colorectal cancer, and that the proliferative activity of colorectal cancer can sometimes be reduced by such preoperative adjuvant therapy.

Interleukin-6 and soluble interleukin-6 receptors in the synovial fluids from rheumatoid arthritis patients are responsible for osteoclast-like cell formation

Chronic immune responses and inflammatory reactions in rheumatoid arthritis (RA) often cause severe destruction of cartilage and bone, but its mechanism is still a matter of controversy. We reported that interleukin-6 (IL-6) alone does not induce osteoclast formation, but soluble interleukin-6 receptors (sIL-6R) triggered the formation in the presence of IL-6 in cocultures of murine osteoblastic cells and bone marrow cells. In this study, we examined the involvement of sIL-6R and IL-6 in joint destruction in patients with RA. Although the frequency of patients having osteoclast-like multinucleated cells in synovium derived from the knee joint was not significantly different between RA (65%) and osteoarthritis (OA) patients (43%), the number of osteoclast-like cells found in the synovium was greater in the former than in the latter. Multinucleated cells obtained from RA synovium expressed the osteoclast-specific phenotype such as tartrate-resistant acid phosphatase, carbonic anhydrase II, vacuolar proton-ATPase and vitronectin receptors at similar levels to those from a human giant cell tumor of bone. The concentration of both IL-6 and sIL-6R was significantly higher in the synovial fluids from patients with RA than with OA. The concentration of IL-6 and sIL-6R correlated well with the roentgenologic grades of joint destruction. Dose-response curves for human IL-6 and human sIL-6R in inducing osteoclast-like cell formation in cocultures indicated that the RA synovial fluids contained sufficient IL-6 and sIL-6R to induce osteoclastogenesis. When synovial fluids from RA and OA patients were added to the cocultures, some of the RA synovial fluids containing high levels of IL-6 and sIL-6R stimulated osteoclast-like cell formation, which was strikingly inhibited by adding anti-IL-6R antibody simultaneously. These results suggest that IL-6 in the RA synovial fluids is at least in part responsible for joint destruction in the presence of sIL-6R through osteoclastogenesis.

Extracellular processing of bone and dentin proteins in matrix mineralization

There are two steps in the process of matrix-mediated bone and dentin mineralization. First, as in other soft tissues, osteoblasts/odontoblasts synthesize collagenous matrices and second, mineral deposits in these matrices at a location distant from the cells that synthesized the matrices. We suggest a sequence of events that lead the matrix to mineralization: the phosphoproteins of bone and dentin are posttranslationally processed by limited proteolysis, then they are extracellularly processed into a more phosphorylated species that, we believe, facilitates mineralization. Our in situ phosphorylation experiments done with [gamma-32P] GTP suggest the existence of extracellular phosphorylation by a casein kinase II (CKII)-like enzyme, the enzyme known to phosphorylate most of the phosphate residues in dentin phosphophoryn and bone sialoproteins (osteopontin and BSP II).

Chemical synthesis of novel biodegradable polyesters

Distannoxane complexes catalyze the ring-opening polymerization of optically active β-butyrolactone (β-BL) to afford a high molecular weight poly(3-hydroxybutyrate). When 1-ethoxy-3-chlorotetrabutyldistannoxane was used as a catalyst (catalyst/(R)-β-BL = 1/8000 at 100 °C for 4 h), poly((R)-3-hydroxybutyrate) was obtained from (R)-β-BL in a yield of 99%. The copolymerizations of (R)-β-BL with racemic β-BL in several ratios gave corresponding stereocopolymers. The copolymerizations of (R)-β-BL with ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone, and L-lactide afforded novel optically active and biodegradable polyesters of high molecular weights, comprising (R)-3-hydroxybutyrate (3HB). The polymerization of (R)-β-BL catalyzed by the distannoxane complexes proceeded by bond breaking between the carbonyl carbon and oxygen atom of the lactone ring (acyl cleavage) with retention of the configuration and little or no racemization. Polymers that have over 80 mol% of the (R)-3HB unit were found to have almost the same degree of biodegradability as the copolyester of 3-hydroxybutyrate and 11% 3-hydroxyvalerate produced by the microbial method.Key words: distannoxane, ring-opening polymerization, poly(3-hydroxybutyrate), poly(3-hydroxyalkanoates), biodegradable polymer.

Bone and brain involvement in a case of diffuse large B cell lymphoma associated with t(2;3)(p12;q27)

We report a 57-year-old male with non-Hodgkin's lymphoma (NHL) associated with t(2;3)(p12;q27). The patient showed bone lesions at presentation and brain involvement at relapse in addition to systemic lymph node swelling. Histological diagnosis was malignant lymphoma, diffuse, large cell, immunoblastic, plasmacytoid. Chromosome analysis revealed t(2;3) which is a variant type of t(3;14)(q27;q32). Fluorescence in situ hybridization (FISH) analysis disclosed splits of signals of BCL-6 gene. Among the cases reported in the literature, the common feature of t(2;3)(p11 or p12;q27) was diffuse, large cell lymphoma of B cell, kappa phenotype and four patients immunosuppressive state before lymphoma.

[Cerebral infarction after the cardiovascular operation]

From January, 1990 through July 1994, 615 adult patients were undergone cardiovascular operation under the cardiopulmonary bypass. Sixteen patients were suffered perioperative cerebral infarction. The etiology of the cerebral infarction was evaluated on the pre and postoperative brain CT findings by the neurologists. In the 283 coronary artery bypass operations, 4 patients suffered watershed infarction (WS) and 4 cerebral embolism. In the 252 valve operations, one WS and one embolism. In the 80 thoracic aortic operations, 5 WS and one embolism, respectively. The risk factors of WS were the elderly, emergency, the longer operative period, and the longer cardiopulmonary bypass period. The risk factor of the embolism were male, preoperative cerebral infarction, the calcified finding of the ascending aorta by the chest CT. It is important to take preventive strategies against the watershed infarction.

[A study of hierarchical structure in personality traits: asymmetry judgments in category breadth and class inclusion]

Many personality theorists postulate a hierarchical structure in trait words. However, most evidences are indirect, mainly because the theorists rely on factor-analytic methods. Assuming a global structure, the factor approach is not necessarily adequate to investigate concrete relationship among trait words. In this study, we used two direct measures to study the hierarchical structure: direct comparison of breadth and asymmetry class-inclusion judgment on trait concepts. Results of three experiments in general confirmed robustness of the hierarchical structure in the domain of personality traits. Traits were organized in the structure at several different levels of abstractness. But the structure was fuzzy in nature, unlike the taxonomy in biology. It was also found that inter-relations among traits could vary considerably from individual to individual. Cognitive complexity may be one of the variables that explain such an individual difference.

Expression of CD44 variant exons 8-10 in gastric cancer

The expression of CD44 variant containing variant exons 8-10 product (CD44v8-10) was studied by western blot analysis and immunohistochemistry in gastric cancers using a monoclonal antibody, 44-1V. On western blots, a single band of 130 kD was recognized in stomach cancer cell lines. CD44v8-10 expression, with reactivity localized in the cell membrane, was found in 65 (33.5%) of the 194 advanced gastric cancers. There was no correlation between CD44v8-10 immunoreactivity and serosal, lymphatic, or lymph node invasion. However, there was significant correlation with CD44v8-10 immunoreactivity and venous invasion. CD44v8-10-positive cancers were more frequently associated with hematogenous metastasis than those which were immunonegative. There was an inverse association between CD44v8-10 immunoreactivity and peritoneal dissemination, especially in diffuse type adenocarcinomas. These observations indicate that CD44v8-10 may play a role in the metastasis of gastric cancer.

Are region-specific changes in fibre types attributable to nonuniform muscle hypertrophy by overloading?

Muscle fibre composition was compared among the proximal (25%), middle (50%) and distal (75%) regions of the muscle length to investigate whether compensatory overload by removal of synergists induces region-specific changes of fibre types in rat soleus and plantaris muscles. In addition, we evaluated fibre cross-sectional area in each region to examine whether fibre recruitment pattern against functional overload is nonuniform in different regions. Increases in muscle mass and fibre area confirmed a significant hypertrophic response in the overloaded soleus and plantaris muscles. Overloading increased the percentage of type I fibres in both muscles and that of type IIA fibres in the plantaris muscle, with the greater changes being found in the middle and distal regions. The percentage of type I fibres in the proximal region was higher than that of the other regions in the control soleus muscle. In the control plantaris muscle, the percentage of type I and IIA fibres in the middle region were higher than that of the proximal and distal regions. With regard to fibre size, type IIB fibre area of the middle and distal regions in the plantaris increased by 51% and 57%, respectively, with the greater changes than that of the proximal region (37%) after overloading. These findings suggest that compensatory overload promoted transformation of type II fibres into type I fibres in rat soleus and plantaris muscles, with the greater changes being found in the middle and distal regions of the plantaris muscle.

Association of HLA-B39 with HLA-B27-negative ankylosing spondylitis and pauciarticular juvenile rheumatoid arthritis in Japanese patients. Evidence for a role of the peptide-anchoring B pocket

OBJECTIVE

To investigate the characteristics of HLA-B27 that render susceptibility to seronegative spondylarthropathies.

METHODS

Serologic HLA class I typing of Japanese patients with ankylosing spondylitis (AS), juvenile rheumatoid arthritis (JRA), and healthy controls, was performed. HLA-B39 subtypes were determined by polymerase chain reaction-sequence-specific oligohybridization.

RESULTS

HLA-B27 was present in 40 of 48 patients with AS (83%), and in only 1 of 210 healthy controls (0.5%). Three of 8 patients (37.5%) who were negative for HLA-B27 were positive for HLA-B39, which was significantly higher compared with the HLA-B27-negative controls (6.2%; P = 0.01). Significant association with HLA-B39 was also noted in the JRA patients (16.7%; P < 0.01), especially in those patients with pauciarticular-onset disease (33.3%; P < 0.01). Ten of 13 HLA-B39-positive patients had subtype B*3901 and 3 had B*3902.

CONCLUSION

Because HLA-B27 and HLA-B39 share Glu at position 45 and Cys at position 67, both of which constitute components of the peptide-anchoring B pocket, and because they possess similar peptide-ligand motifs, our results may support either the role of the peptides presented by class I antigens or the importance of Cys at position 67, in the development of spondylarthropathies and pauciarticular-onset JRA.

[Successful valvuloplasty for isolated tricuspid regurgitation due to traumatic ruptured papillary muscle]

A 44-year-old man suffered from an traffic accident on May 27, 1994. He was transferred to a hospital because of emergent operation for a laceration of liver, right-sided hemothorax and pneumothorax. After surgical treatment for these lesions, he was doing well. However, systolic murmur appeared from August, 1994. By echocardiography and cardiac catheterization, he was diagnosed of isolated tricuspid regurgitation due to traumatic ruptured papillary muscle. Because right heart failure was progressive, an operation was recommended. At operation, annular dilatation of tricuspid valve and ruptured papillary muscle of anterior leaflet were found. And the ruptured end of right ventricular aspect was recognized. Therefore, we performed tricuspid valvuloplasty and annuloplasty. Postoperative course was uneventful. And residual regurgitation was not detected by right ventriculography. Especially, in patients with tricuspid regurgitation due to ruptured papillary muscle, symptoms usually begin soon after trauma. Therefore, an operation should be recommended promptly in the presence of right heart failure not relieved by medical treatment. And an earlier operation could increase the feasibility of tricuspid valvuloplaty, and the possibility of maintaining sinus rhythm.

Reciprocal regulation by cyclic nucleotides of the differentiation of rat osteoblast-like cells and mineralization of nodules

The effects of cAMP and cGMP on the differentiation of osteoblast-like cells derived from rat calvariae and on the formation of bone in vitro were studied. Continuous culture of osteoblast-like cells in the presence of 8-bromo-cyclic AMP (8-Br-cAMP) resulted in the dose-related inhibition both of the synthesis of cellular alkaline phosphatase (ALPase), which is known as a marker of osteoblastic differentiation, and of the formation of mineralized nodules, which is a model of the formation of bone in vitro. By contrast, 8-bromo-cyclic GMP (8-Br-cGMP) promoted the synthesis of ALPase and the formation of mineralized nodules. Northern blot analysis revealed that these cyclic nucleotides modulated the steady-state levels of mRNAs for ALPase and osteocalcin, a bone-matrix protein that is specifically produced by osteoblast. The present results indicate that cAMP and cGMP act reciprocally to regulate osteoblastic differentiation and the subsequent formation of mineralized nodules.

Reconstitution of the metal-tetracycline/H+ antiporter of Escherichia coli in proteoliposomes including F0F1-ATPase

The tetracycline resistance gene (tetA) was cloned downstream of the lac promoter. When expression of the tetA gene in E. coli cells carrying the lac Iq gene was induced with isopropyl beta-D-thiogalactopyranoside, the tetracycline resistance protein (TetA) was overproduced, amounting to about 30% of the integral cytoplasmic membrane protein. Essentially pure TetA protein could be obtained by solubilization with 1.25% n-octyl-beta-D-glucopyranoside and one-step purification by DEAE Sepharose CL-6B column chromatography. The TetA protein was incorporated into proteoliposomes with F0F1-ATPase. The proteoliposomes exhibited [3H]tetracycline transport dependent on ATP hydrolysis. The specific activity was about 2 nmol/mg protein/min. The proteoliposomes also showed H+ efflux coupled with tetracycline influx. Tetracycline/H+ antiport by proteoliposomes reconstituted with the Ser-65-->Cys mutant TetA protein was inhibited by N-ethylmaleimide. These results proved for the first time that the tetracycline/H+ antiport is only mediated by the TetA protein.

[A case of coronary artery bypass grafting using arterial grafts in a patient with Buerger's disease]

A 50-year-old male with Buerger's disease underwent coronary artery bypass grafting (CABG) using left and right internal thoracic arteries (LITA and RITA). In our case, his saphenous veins could not be used because of migrating thrombophlebitis, and we could not use right gastroepiproic artery because he had undergone gastrectomy for gastroduodenal ulcer. He underwent CABG with LITA-left anterior descending artery and free RITA-right coronary artery. Postoperative coronary angiogram showed good patency of both grafts, and his postoperative course has been uneventful for 42 months. To our knowledge, there is no report of CABG in a patient with Buerger's disease, but we think the use of arterial grafts is useful in such cases.

Left ventricular end-systolic volume index in patients with ischemic cardiomyopathy predicts postoperative ventricular function

BACKGROUND

We investigated the usefulness of the preoperative left ventricular end-systolic volume index (LVESVI) as a predictor of postoperative ventricular function.

METHODS

We retrospectively reviewed the records of 310 patients who underwent coronary artery bypass grafting and identified 20 patients with ischemic cardiomyopathy with a preoperative ejection fraction less than 0.30. We determined the preoperative and postoperative ejection fraction, LVESVI, and left ventricular enddiastolic volume index using biplane left cineventriculography. Patients were divided into groups depending on whether their preoperative LVESVI was less than 100 mL/m2 (group A, n = 10) or greater than 100 mL/m2 (group B, n = 10).

RESULTS

The mean ejection fraction increased significantly after coronary artery bypass grafting in group A from 0.25 +/- 0.05 to 0.40 +/- 0.09 (p < 0.01), but did not change significantly in group B (0.26 +/- 0.05 versus 0.23 +/- 0.06). The mean LVESVI decreased significantly in group A from 83.2 +/- 13.7 to 61.7 +/- 20.4 mL/m2 after operation (p < 0.05), but did not change significantly in group B (124.7 +/- 21.0 versus 121.5 +/- 37.6 mL/m2). In group B, 4 patients had signs of congestive heart failure during the follow-up period and had to be rehospitalized.

CONCLUSIONS

The mean ejection fraction improved significantly after coronary artery bypass grafting in patients with a preoperative LVESVI less than 100 mL/m2, despite the presence of a global left ventricular ejection fraction less than 0.30. Our results suggest that the preoperative LVESVI predicts the postoperative status and left ventricular function in patients with ischemic cardiomyopathy.

Second-site suppressor mutations for the Asp-66-->Cys mutant of the transposon Tn10-encoded metal-tetracycline/H+ antiporter of Escherichia coli

Asp66 is the only essential acidic residue in the putative hydrophilic loop2-3 region of the transposon Tn10-encoded metal-tetracycline/H+ antiporter [TetA(B)] [Yamaguchi, A., Nakatani, M., & Sawai, T. (1992a) Biochemistry 31, 8344-8348]. Escherichia coli cells producing a D66C mutant of TetA(B) showed no tetracycline resistance. A spontaneous second-site revertant was isolated from the cells carrying the D66C mutant gene, which showed moderate resistance to tetracycline [minimum inhibitory concentration (MIC), 50 micrograms/mL]. The entire sequencing of the revertant genes revealed two secondary mutations, i.e., the codon 40 of GCT (Ala)-->GAT (Asp) and T-->G at 17 bases upstream from the initiation codon of the tetA gene. There was a T-->G mutation at position -17, which was a mutation in the tet promoter/operator region, which caused a decrease in TetA(B) production. The full expression of the A40D/D66C double and the A40D single mutants, which were constructed by site-directed mutagenesis, was deleterious for cell growth. The -17T-->G mutation mitigated the deleterious effect of these mutants through reduction of expression. The -17T-->G single mutation introduced into the wild-type tet gene did not affect the level of resistance, although the expression was significantly reduced. Intact cells carrying the A40D/D66C and -17T-->G/A40D/D66C mutant plasmids showed a reduced level of tetracycline accumulation due to active efflux, whereas no significant tetracycline uptake was observed in inverted membrane vesicles prepared from these mutant-producing cells. The A40D mutation is located at opposite side of the membrane to the D66C mutation in the putative secondary structure of TetA(B). The second-site mutation might mediate its effects through a structural perturbation propagated along the polypeptide backbone.

[Clinical significance of selective cerebral perfusion with cold blood on the brain protection]

In 42 patients with thoracic aortic disease, a selective cerebral perfusion with 16 degrees C cold blood was applied for the brain protection during the repair of the thoracic aorta. The surgical repair consisted of the replacement of the ascending aorta (9 cases), the ascending aorta and aortic arch (12 cases), the aortic arch (18 cases), and the aortic arch and descending aorta (3 cases). Twenty-two patients of them (52%) required emergency surgery and four patients died due to postoperative complications including visceral organ ischemia (2 cases) and multiple organ failure (2 cases). The mortality rate of this group was 18.2% (4/22 cases). In elective surgical classes, one patient died due to intraoperative coronary embolism. The mortality rate of this group was 5.0% (1/20 cases). No postoperative obvious brain defect was observed except one old patient (85-year-old female) with ruptured aortic arch who already had the brain infarction preoperatively. She died due to multiple organ failure with unconsciousness. Other patients including the patients with long cerebral perfusion (> 180 min) recovered well and returned to normal daily life. The selective cerebral perfusion with cold blood was easy to prepare and demonstrated the superb efficacy of brain protection in the patient.

[Successful surgical treatment of mitral regurgitation associated with anti-phospholipid syndrome and systemic lupus erythematosus]

A 39-year-old woman with the diagnosis of mitral regurgitation was admitted to our hospital for surgical treatment. Cerebral thromboembolism and spontaneous abortion had been repeated in her past history. She was suffered from chronic renal failure associated with systemic lupus erythematosus (SLE) and anti-phospholipid syndrome (APS). An operative procedure was recommended because of the progressive heart failure due to mitral regurgitation. For renal failure, continuous ambulatory peritoneal dialysis (CAPD) was introduced at one month before operation. As the operative procedure, valve replacement using Carpentier-Edwards bioprosthesis (27 mm) was done rather than valve reconstruction, because chordal rupture of posterior leaflet and severe hypertrophy of both leaflets were recognized. During operation, uncontrollable bleeding was not observed. However, platelet transfusion was needed. We use warfarin and antiplatelet agents jointly as postoperative anticoagulant therapy. Thromboembolic episodes have not been observed 4 years postoperatively. Relationship between SLE with APS and cardiac valvular lesions has been focused. The present case was considered to be the interesting case which various devices were necessary to operative management including chronic renal failure, cardiopulmonary bypass, selection of prosthetic heart valve, and postoperative anticoagulant therapy for preventing thrombus formation.

[Re-replacement of Starr-Edwards mitral valve (model 6320) for prosthetic valve endocarditis 22 years after replacement]

The patient was a 43-year-old woman who had undergone mitral valve replacement with Starr-Edwards ball valve (model 6320) 22 years ago. Perivalvular mitral leakage due to prosthetic valve endocarditis and tricuspid regurgitation were found. She underwent re-replacement of the mitral valve. The operative findings revealed almost intact valvular function of the ball valve. As far as we know, 22 years is the longest follow-up for the Starr-Edwards ball valve which has maintained normal function.

Evaluation of the antithrombogenicity of a new microdomain structured copolymer

A new antithrombogenic material was studied, fluorine-acryl-styrene-urethane-silicone (FASUS) copolymer, the theoretical basis of which attributed to its hydrophilic and hydrophobic microdomain structure. In this series of experiments, the blood compatibility of this copolymer was evaluated in vitro and ex vivo. For the in vitro evaluation, a whole blood clotting test and the microsphere column test were performed. For the ex vivo evaluation, two series of shunt tests in rabbits were performed, one was the arterioartery (A-A) shunt model, and the other was the arteriovenous (A-V) shunt model. The antithrombogenicity was assessed by measuring the shunt obstructive time in the A-A shunt experiment. The A-V shunt experiment was assessed by measuring the circulating platelet counts, platelet aggregability, activated partial thromboplastin time (APTT), and prothrombin time (PT). In the whole blood clotting test, FASUS revealed the significantly longer blood clotting time than that of the control glass tubings (19.7 +/- 1.0 versus 6.5 +/- 0.7 min, p < 0.001). In the microsphere column test, the coated group had a 30% reduction of the platelet number in the eluted blood in contrast with a marked decrease of 70% in the control group (p < 0.05). In the ex vivo A-A shunt experiment, the occlusion time for the FASUS-coated group was significantly longer than that of the control (109.7 +/- 17.3 versus 3.0 +/- 0.4 min, p < 0.05). The A-V shunt experiment showed that the FASUS copolymer suppressed the decrease in platelet counts and tended to improve prolonged APTT compared with that of the control. Clinically, in 25 patients, we placed coated FASUS copolymer into the cannulas for use in percutaneous cardiopulmonary support (PCPS) procedures. There was no evidence of thrombus on the blood contacting surface and no thromboembolism in major organs clinically or upon postmortem examination. In summary, this new copolymer may be effective in preventing thrombus formation in vitro, ex vivo, and in clinical situations.

[The role of CD44 adhesion molecules]

CD44 is a transmembrane glycoprotein involved in the interaction between cells and extracellular matrix. CD44 is ubiquitously expressed on cells, and has been thought to be a cell adhesion molecule with proposed functions in extracellular matrix binding, cell migration and lymphocyte homing. In 1991, Stamenkovic et al. showed the existence of two forms of CD44: a hematopoietic (standard) and an epithelial form which was highly expressed by carcinomas. The alternative splicing of 10 variant exons encoding the membrane proximal portion of the external domain of CD44, in particular, results in many variant isoforms. These may play a critical role in malignant behavior and in determining organ specificity in metastasis.

Proinflammatory cytokine levels in patients undergoing cardiopulmonary bypass. Does lung reperfusion influence the release of cytokines?

Proinflammatory cytokines have been implicated in mediating tissue injury after cardiopulmonary bypass. Causative factors of inflammatory response after cardiopulmonary bypass include contact of the blood with the extracorporeal circuit and heart-lung reperfusion injury when discontinuing bypass. To evaluate proinflammatory cytokine release during cardiopulmonary bypass, plasma levels of interleukin-6, 8, and monocyte chemoattractant factor were measured in the radial artery (for systemic blood) and left atrium before and after cardiopulmonary bypass. A total of 13 patients were studied, with no deaths or complications. In both radial artery and left atrium, interleukin-6, 8, and monocyte chemoattractant factor rose significantly after cardiopulmonary bypass (p < 0.05 versus before cardiopulmonary bypass). These changes may have been caused by removal of the aortic cross clamp and recommencement of artificial ventilation, which result in reperfusion of the pulmonary capillary beds. There were no differences in cytokine levels after cardiopulmonary bypass in the radial artery and left atrium. This result suggested that lung reperfusion injury after cardiopulmonary bypass may not be the major causative factor of the release of proinflammatory cytokines.

A possible role of vitamin D receptors in regulating vitamin D activation in the kidney

The vitamin D endocrine system is regulated reciprocally by renal 25-hydroxyvitamin D3 1 alpha- and 24-hydroxylases. Previously, we reported that renal proximal convoluted tubules, the major site of 1 alpha, 25-dihydroxyvitamin D3 production, have vitamin D receptors. In the presence of vitamin D receptors, renal proximal convoluted tubules cannot maintain the state of enhanced production of 1 alpha, 25-dihydroxyvitamin D3. To clarify this discrepancy, we proposed a working hypothesis for the reciprocal control of renal 25-hydroxyvitamin D3 1 alpha- and 24-hydroxylase activities. In rat models of enhanced renal production of 1 alpha, 25-dihydroxyvitamin D3, expression of vitamin D receptors and 25-hydroxyvitamin D3 24-hydroxylase mRNAs was strikingly suppressed in renal proximal convoluted tubules but not in the cortical collecting ducts. In vitamin D-deficient rats with up-regulated renal 25-hydroxyvitamin D3 1 alpha-hydroxylase activity, expression of vitamin D receptor mRNA in renal proximal convoluted tubules was also down-regulated, indicating that the down-regulation of vitamin D receptor mRNA is not the result of the enhanced production of 1 alpha, 25-dihydroxyvitamin D3. In Japanese quail models with up-regulated renal 25-hydroxyvitamin D3 1 alpha-hydroxylase activity by sex steroids, expression of vitamin D receptor mRNA was also down-regulated in the kidney but not in the duodenum. These results suggest that the down-regulation of vitamin D receptors plays a critical role in production of 1 alpha, 25-dihydroxyvitamin D3 in renal proximal convoluted tubules.

Microgravity generated by space flight has little effect on the growth and development of chick embryonic bone

Seven days' space flight of fertilized chicken eggs pre- incubated for 7 and 10 days on earth caused no differences in the morphology of osteoblasts, osteoclasts, and osteocytes of humerus and tibia from those of control embryos. Bone-resorbing and -forming activities of the femur were not different between control and flight groups. As a consequence, calcium and phosphorus contents of the femora between control and flight groups were not changed. Alkaline phosphatase activity of 3 different regions (resting cartilage, growth cartilage, and cortical bone) of tibia showed no significant difference between control and flight groups. No significant difference of gene expressions of hepatocyte growth factor and receptors of fibroblast growth factor was observed in perichondrium, trabecula, and skeletal muscles and tendons of hind limbs between control and flight groups. Unlike the results of previous space flight experiments in which young growing mammals were used, these morphological and biochemical results indicate that microgravity has little effect on bone metabolism of the chick embryo.

[Intermediate to late results of aortic or mitral valvuloplasty by rasping procedure]

We have proposed Rasping procedure as one of the methods of aortic valvuloplasty (A-Rasping) and defined as debridement of the thickened surface of the rheumato-degenerative aortic valve using an electric rasper since 1986. Furthermore, we have extended this technique to mitral valvuloplasty (M-Rasping). The purpose of this study is to evaluate intermediate to late results of valvuloplasty by Rasping procedure. From 1986 to 1994, this method was carried out on 14 patients with mild-to-moderate aortic valve disease in severe mitral valve disease or coronary artery disease, and on 6 patients with mitral stenosis. In A-Rasping group, aortic regurgitation was found in 10 patients and aortic stenosis was found in 4 patients. The degree of regurgitation, the transvalvular pressure gradient, and the pre- and postoperative cardiac function in both group were investigated chronologically by echocardiography. In this series of patients, no hospital mortally including operative death was observed. Furthermore, reoperation for repaired aortic or mital valve was not required. In A-Rasping group, 2 late deaths (14.2%) occurred at 1 year and 4 years after operation. Cause of 2 late deaths was prosthetic valve endocarditis in mitral position. In A-Rasping group, at 1 year after operation, regurgitation was reduced to degree I or less in all patients. However, at the 3rd postoperative year, regurgitation increased to degree II in 2 patients. As compared with the preoperative values, the transvalvular pressure gradient significantly decreased in 4 patients (29.5 +/- 7.6 mmHg vs 12.5 +/- 5.0 mmHg, p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)