Superoxide anions in the pathogenesis of talc-induced cerebral vasocontraction

We have recently reported that sustained contraction of the canine basilar artery induced by the intrathecal injection of talc (crystallized hydrous magnesium silicate) mimicked delayed vasospasm following subarachnoid haemorrhage. The present study aims to examine the pathomechanism underlying talc-induced vasocontraction, from the viewpoint of free radical theory, which has been established as a cause of delayed vasospasm. We estimated the effects of a prolonged intrathecal infusion of human recombinant Cu/Zn superoxide dismutase (hr SOD) on the contraction of the basilar artery caused by the intrathecal injection of talc in beagle dogs, which were assigned to the three groups: G1, sham operation with saline treatment; G2, talc injection with saline treatment; and G3, talc injection with 2 ml of hr SOD (7 x 10(4) U/ml) treatment. Talc administration resulted in the reduction in the angiographic calibre of the basilar artery by 63 and 61% on days 3 and 7 (G2). The treatment with hr SOD (G3) led to a significant attenuation of talc-induced contraction of the basilar artery on days 3 (P < 0.05 vs. G2) and 7 (P < 0.05 vs. G2). In the basilar artery wall of days 3 and 7 in G2, pathological changes such as myonecrosis, cytoplasmic vacuolation and detached intercellular junctions were observed. However, these pathological changes almost disappeared in G3. The present findings suggest that superoxide anions may initiate and/or mediate talc-induced vasocontraction and subsequent structural damage of the basilar artery.

Suppression of episodic growth hormone secretion in streptozotocin-induced diabetic mice: time-course studies on the hypothalamic pituitary axis

To elucidate the roles of the hypothalamic peptides, GH-releasing hormone (GRH) and somatostatin (SRIH), potentially responsible for altered GH dynamics in diabetes, we studied the time courses of their changes in level associated with altered GH secretion in streptozotocin (STZ)-induced diabetic mice. Diabetic mice were used at 4, 7, and 14 days after STZ injection for analyses of 1) GH secretion in vivo, 2) hypothalamic GRH and SRIH messenger RNA (mRNA) levels, 3) pituitary GH mRNA and protein contents, and 4) pituitary GH response to GRH in vitro. GH secretion was completely suppressed 7 and 14 days after STZ injection. The hypothalamic GRH mRNA level was reduced to 59.8%, 61.2%, and 48.5% of control values at 4, 7, and 14 days, respectively. In contrast, the hypothalamic SRIH mRNA level was not altered at all of these time points. Pituitary GH mRNA and protein contents were significantly reduced to 70.2% and 61.5% of those in controls, respectively, only at 14 days. Pituitary GH responses to GRH at three doses (10, 50, and 250 nM) in vitro were remarkably increased at 4, 7, and 14 days. These findings indicate that the diabetic state rapidly and primarily inhibits hypothalamic GRH gene expression without affecting SRIH. A persistent decrease in hypothalamic GRH tone has been suggested to result in inhibition of GH synthesis in the pituitary. Enhancement of GH responsiveness to GRH may be due to the up-regulation of GRH receptors in the pituitary.

Selection of absorption lines for I(2)-planar laser-induced fluorescence measurement of temperature in a compressible flow

It is very important for I(2)-planar laser-induced fluorescence measurement of temperature in a compressible flow to choose a pair of absorption lines appropriate to the temperature range. The method for selection of suitable pairs of absorption lines of I(2) in the transition of B(3)II(ou) + (ν' = 43) ? X(1)Σ(g) + (ν" = 0)is described. By the use of many pairs of absorption lines, the temperature dependence of the ratio between the fluorescence signals is calculated theoretically and is also investigated in experiments in which several pairs are applied to determination of the temperature distribution of a supersonic free jet.

Inhibitory effects of interleukin-1 on growth hormone secretion in conscious male rats

Although various pathophysiological effects of interleukin (IL) on the CRF-ACTH-adrenal axis and gonadotropin secretion have been studied extensively, the effects of IL on GH secretion still remain to be elucidated. We investigated the possible effects of IL on GH secretion in six groups of conscious rats. In four groups, IL was administered by continuous iv infusion and in the other two, by intracerebroventricular injection. Saline-treated rats served as controls for these groups. Sequential blood sampling was performed every 20 min in all groups, and the plasma GH concentration was determined by RIA. The expression of hypothalamic c-fos protein in a separate group was examined by immunohistochemistry. Continuous infusion of both IL-1 alpha and IL-1 beta (10 ng/min) significantly inhibited GH surges. The plasma IL-1 level was elevated to 2-3 ng/ml. Continuous iv infusion of IL-2 and IL-6 had no effect on GH secretion. The intracerebroventricular injection of both IL-1 alpha and IL-1 beta significantly inhibited GH surges, and the inhibitory effect was much greater for IL-1 beta than for IL-1 alpha. Continuous iv infusion of IL-1 beta markedly stimulated c-fos expression in specific hypothalamic nuclei, particularly in the paraventricular nucleus. These findings suggest that, in the rat, IL-1 inhibits GH secretion through its peripheral and central actions.

Gene expression of hypothalamic growth hormone (GH)-releasing hormone and somatostatin does not correlate with pulsatile secretion of GH in the adult mouse

The secretion of growth hormone (GH) shows a pulsatile pattern in many mammalian species, and depends on the interaction of two hypothalamic hormones, GH-releasing hormone (GHRH) and somatostatin (SRIH). A surge of GHRH secretion into the hypophysial portal blood induces peak secretion of GH from the anterior pituitary. To study whether the rhythmic and reciprocal oscillation in secretion of GHRH and SRIH are associated with changes in synthesis of these peptides, we examined the expression of hypothalamic GHRH and SRIH mRNA by Northern blotting during trough and peak phases of GH secretion in male mice. Hypothalamic GHRH and SRIH mRNA levels did not differ between trough and peak phases of GH secretion. This result suggests that changes in GHRH and SRIH secretion have little association with changes in the synthesis of these peptides at the hypothalamus in the male mouse.

(S)-C alpha-ethyl, C alpha-benzylglycine [(S)-(alpha Et)Phe] peptides fold in left-handed helical structures

The first x-ray diffraction structure analysis of a C alpha-ethyl, C alpha-benzylglycine [(alpha Et)Phe]-containing peptide, N alpha-benzyloxycarbonyl-alpha-aminoisobutyryl-alpha-amino-isobutyr yl-(S)- C alpha-benzylglycyl-alpha-aminoisobutyric acid (methanol solvate), has been performed. In the crystal state the N alpha-protected tetrapeptide is folded in an incipient, left-handed 3(10)-helical structure. This finding confirms that the relationship between (alpha Et)Phe alpha-carbon chirality and screw sense of the helix that is formed is opposite to that exhibited by protein amino acids, including Phe.

Enhancement of aromatic amino acid-nucleic acid base stacking interaction by metal coordination to base: fluorescence study on a tryptophan-Pt(II)-guanine ternary complex

In order to investigate the effect of the Pt(II) ion on the stacking interaction between tryptophan and a guanine base, the quenching of Trp fluorescence was monitored for some systems in the absence and presence of the metal ion, and the association constants were obtained by the analysis of Eadie-Hofstee plots. All spectral data suggested that the stacking interaction is enhanced by the Pt(II) coordination to the guanine N7 atom. The result indicates the importance of the metal ion as a bookmark in the specific recognition of a nucleic acid base by an aromatic amino acid residue.

Design of noncovalent trypsin inhibitor based on the X-ray crystal structure of the complex

The inhibitory mechanism of trans-4-aminomethylcyclohexanecarbonyl-L-phenyl-alanine-4-carbo xymethylanilide (1), a noncovalent serine protease inhibitor synthesized based on previous structure-activity studies, was clarified based on the X-ray crystal structure of the complex (2.2 A resolution, R = 0.175), where the amino group of the aminomethylcyclohexane moiety was bifurcately hydrogen-bonded to the carboxyl oxygens of Asp 189 side group (specificity pocket), and the hydrogen bonds of the cyclohexanecarbonyl oxygen to NHs of Gly 193 and Ser 195 residues (oxyanion hole) and of Phe NH to Ser 195 O gamma atom (catalytic triad) were observed. In contrast, the Phe benzene moiety and terminal carboxymethylanilide of 1 were not well located on the electron density map, suggesting the conformational freedom of these P1' and P2' sites at the binding pocket. Based on these insights, trans-4-aminomethylcyclohexanecarbonyl-4-nitro-L-phenylalanine-4-+ ++benzoylanilide (2) was designed, in which the P1' and P2' sites were modified so as to effectively interact with the amino acid residues of trypsin binding pocket via hydrogen bonding and van der Waals interactions, respectively. Consequently, 2 showed 40 times higher inhibitory activity against trypsin than 1.

Characteristics of non-small cell lung cancer 3 cm or less in diameter

We retrospectively investigated 308 cases of non-small cell lung cancer of < or = 3 cm diameter. There were 204 adenocarcinomas, 78 squamous cell carcinomas, 15 large cell carcinomas, and 11 other carcinomas. According to TNM staging, there were one case stage 0, 208 stage I, 22 stage II, 49 stage IIIA, 15 stage IIIB, and 13 cases stage IV. T1 disease was seen in 262 cases, T2 in 19, T3 in 10, T4 in 16, and Tis in 1. N0 disease was seen in 217 cases, N1 in 30, N2 in 60, and N3 in 1. The 5-year survival rate of all cases was 63%. There were statistically significant differences among T status (T1 vs. T3, T4), N status (N0 vs. N1, N2), and M status (M0 vs. M1) (P < 0.01). The 5-year survival rates of cases with adenocarcinoma and squamous cell carcinoma were 60% and 64%, respectively. In 204 cases of adenocarcinoma, T3 disease was found in one case, T4 disease in 15 (7%), and nodal involvement (N1 + N2) was present in 69 (34%). In 78 cases of squamous cell carcinoma T3 was seen in 6 (8%), T4 in 1, and nodal involvement in 14 (18%). The incidence of T3 disease, T4, and N(+) varied significantly according to histology (P < 0.05). Our investigation suggested that cases of small-sized lung cancer were often at an advanced stage at detection, and that the spread of disease differed according to histology. The patient with small-sized lung cancer should be offered a standard operation regardless of histology.

[A clinical study of six cases of toxic shock-like syndrome by group A Streptococcus]

We have encountered six cases with toxic shock-like syndrome (TSLS) by Group A Streptococcus since 1978. Every patient had from the onset flu-like symptoms or high fever and immediately developed some of the following clinical signs: hypotension, acute renal failure, disseminated intravascular coagulation (DIC), and adult respiratory distress syndrome (ARDS). Three of the six patients died with rapid clinical courses and three survived. As for the surviving patients, early administration of antibiotics and anti-DIC therapy were effective. Streptococcus pyogenes were isolated from the blood in five of the patients, ascites from another, and necrotizing tissue in one patient. The serovars of the isolated strains were typed as T1/M1 in three, T8 in one, and T28 in another. The toxin-type of the strains were typed as B in four and B + C in one. Though there have been few reports of TSLS before 1992 in Japan, it is supposed that many TSLS cases may have potentially occurred.

[Audiologic evaluation in a family showing diabetes mellitus and deafness associated with a mutation in mitochondrial DNA]

An A to G transition at nucleotide 3,243 in the tRNA(Leu)(UUR) gene of mitochondrial DNA has recently been identified as a pathogenic point mutation which is associated with diabetes mellitus and sensorineural deafness in several pedigrees. We have also reported a family showing the association of deafness and diabetes mellitus as the predominant clinical features with this mutation. Audiologic data from two patients in this family are presented. Both had a bilaterally symmetrical sensorineural hearing loss at all frequencies. As is often the case with deafness associated with a mitochondrial disorder, the pure-tone threshold values were maximal at high frequencies in both patients. The audiologic work-up presented not only cochlear characteristics but also signs suggestive of retrocochlear disturbance with poor speech discrimination scores as compared to pure-tone thresholds, although auditory brain-stem responses showed neither wave delay nor prolonged interpeak latencies.

The close relationship between growth factors and the nucleolar organizer regions in adenocarcinoma of the lung

We examined immunohistochemically 111 cases of primary adenocarcinoma of the lung, for transforming growth factor alpha (TGF alpha) or epidermal growth factor (EGF), and argyrophilic nucleolar organizer regions (AgNORs). The presence of more than 75% positive cells for both growth factors was designated as a high-GF, while all others were considered to be a low-GF. If AgNORs counts were more than 5.00, it was considered to be a high-AgNORs group, while less than 5.00 was designated as a low-AgNORs group. In our 111 examined specimens, there were 51 (46%) cases of high-GF, and 64 (58%) with high AgNORs. The 5-year survival rates of the patients with a high-GF and low-GF were 34% and 57% (P < 0.05) respectively, while those with high-AgNORs and low-AgNORs were 21% and 81% (P < 0.001), respectively. In the cases of high-AgNORs, the 5-year survival rates of the patients with high-GF and low-GF were 0% and 36% (P < 0.05), respectively. However, in the cases of low-AgNORs, the 5-year survival rates of the patients with high-GF and low-GF were 83% and 79%, respectively. These data suggest that growth factors might be related to the biological malignancy of tumours with a high cell proliferation.

Solution conformation of mu-selective dermorphin and delta-selective deltorphin-I in phospholipid micelles, studied by NMR spectroscopy and molecular dynamics simulations

Complete proton resonance assignments of the naturally occurring mu-selective dermorphin (H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2) and delta-selective deltorphin-I (H-Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2) were carried out by two-dimensional 1H-NMR techniques to investigate the conformational features in the membrane-mimetic micelles of perdeuterated dodecylphosphocholine. Fifty possible three-dimensional structures for respective peptides were generated by means of distance geometry calculations, all of which satisfy the proton-proton distances derived from NOE measurements within the allowable range, and 25 of them were subjected to the molecular dynamics simulations for 10 ps, in which the NOE distances were included as the energetic constraints. Although conformers simulated for dermorphin showed relatively large conformational variations because of the limited NOE data, most of them were characterized as an entirely folded structure bent at the Gly4 residue, where each of the N- and C-terminal tetrapeptides took an extended conformation. On the other hand, most conformations of deltorphin-I showed the common feature that the N-terminal Tyr-D-Ala-Phe-Asp and C-terminal Val-Val-Gly-NH2 sequences took respective folded conformations, and these were almost at right angles on the border of the Asp-Val sequence. These conformational characteristics are discussed in terms of the possible relationship with the mu/delta-opioid receptor selectivity.

Beneficial effect of thromboxane A2 synthetase inhibitor (OKY-046) on 24-hr simple hypothermic preservation of the canine pancreas graft

This study was performed to investigate the potential protective effect of OKY-046, an inhibitor of thromboxane A2 synthetase, on the viability of 24-hr preserved canine segmental pancreas graft. Each graft was preserved in either cold Euro-Collins (E-C) solution (control group; n = 5) or E C+OKY-046(10(-4)M) solution (OKY-046 group; n = 5). In both groups, grafts were preserved for 24 hr and calculated the total levels of 6keto-prostaglandin F1 alpha (6ket-PGF1 alpha) and thromboxane B2(TxB2) in the preservation solution per pancreas graft weight at the time point of 0,3,7,12,24 hr after preservation. The efficacy of OKY-046 in protecting ischemically stressed grafts was examined by histological findings of the grafts before transplantation and blood flow of the transplanted pancreas graft. During 24-hr preservation time, increased production of 6ket-PGF1 alpha and decreased production of TxB2 were found in OKY-046 group. Histologically ischemic damage of the acinar cells was observed in the control group, but it was milder in the OKY-046 group. The blood flow of the transplanted pancreas in the OKY-046 group were higher than that in control group. In the OKY-046 group, all dogs survived with functioning grafts, although some grafts were lost in the control group. These results suggest that there is a possibility that OKY-046 may contribute to the improvement of the survival rate in segmental pancreas transplantation.

A unified model for cell-killing by heat: interpretation of continuous, step-down, step-up and split heating

We have already proposed a model for the lethal effects of heat on cells. In the model, a three-step process for cellular inactivation was hypothesized: 1) heating produces sublethal damage; 2) the damage is repaired in a certain time period; 3) the cell is inactivated when it undergoes cumulative sublethal damage to the extent that it cannot be repaired. Using the previous model, we investigated the modifications of the survival curve in 1) continuous heating, 2) step-down heating, 3) step-up heating, and 4) recovery from the thermal injury by split heating. These four phenomena were explained well with the mathematical model.

CT assessment of postirradiation changes in the rectum and perirectal region

Postirradiation changes in the rectum and perirectal tissue were assessed by computed tomography (CT) in 55 patients (total of 60 examinations) and correlated with radiation dose and time elapsed. Thickening of the perirectal fascia, increased density of the perirectal fat, and swelling of the rectal wall occurred in 48, 60, and 8% of patients, respectively, regardless of radiation dose within 30 Gy. However, widening of the presacral space was seen in 8% of patients receiving a rectal dose of less than 45 Gy, a percentage that increased to 16% for patients receiving 45 Gy or more. Thickening of the perirectal fascia, increased density of the perirectal fat, widening of the presacral space, and muscular changes were seen regardless of the time from the start of therapy. CT does not appear to be reliable enough in detecting residual or recurrent tumor in the rectum. However, knowledge of the CT features of postirradiation changes is helpful for diagnosis in patients with pelvic malignancies.

[Detection of a mutation in mitochondrial DNA in a family with sensorineural deafness and diabetes mellitus as the predominant clinical features]

An A to G transition at nucleotide 3,243 in the tRNA(Leu(UUR)) gene of mitochondrial DNA (mtDNA) has been suggested to be the disease-related mutation for MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). Recently, the same mutation has also been found in several pedigrees with maternally inherited diabetes mellitus and sensorineural deafness. We report here a family showing the association of deafness and diabetes mellitus, as the predominant clinical features, with this mutation. The mutation was detected by restriction-enzyme analysis of the relevant PCR-amplified segment of the mtDNA, in two generations. In this family, it is noteworthy that two members with the mutation had some symptoms of MELAS such as short stature, seizures and mental retardation and that one had no clinical symptoms though the mtDNA mutation was identified in his blood. The findings in this family demonstrate the diversity of clinical expression of the mtDNA mutation and suggest that a combination of sensorineural deafness and diabetes mellitus is only one typical presentation of the various phenotypic features caused by the 3,243 mutation.

Establishment and characterization of human fetal liver epithelial cell line transfected with SV40 T antigen

The aim of the present study was to establish a stable cell line useful for the study of growth and differentiation of human fetal liver cells. We have established an immortalized human fetal liver cell line (designated NFL/T) by transfection with simian virus 40 (SV40) large T antigen, without any culture crisis. The cells showed growth properties similar to normal cells, including density-dependent cell growth. Electron microscopy demonstrated liver-specific differentiated morphological properties. Moreover, positive albumin and cytokeratin 7 production was detected immunologically. Thus, the NFL/T cell line is less transformed than the other fetal liver cell lines established by this method, and might be useful to study the growth and differentiation of human fetal liver cells.

Survival following resection for lung cancer as a second primary cancer

A second operation was done on 59 patients with lung cancer (7.4% of all those with lung cancer) as a second primary (double primary), during 1974-1991. There were 16 synchronous tumors (interval less than one year) and 43 metachronous tumors (interval over one year). The criteria for diagnosing lung cancer as a second primary from intrapulmonary metastases were any of the following: 1) different histologic type; 2) origin from carcinoma in situ; 3) gross appearance suggestive of primary lung cancer. The initial operation was in the stomach in 14 patients and in the lung in 10. The overall 5-year survival rate in the double primaries was 57.8%, and the prognosis was similar to those in the single primaries of the lung. Nineteen patients died from the second tumor following the second operation, compared with 5 from the initial tumor. The incidence of primary lung cancer increases, and close follow-up after resection for malignant neoplasms detects a new shadow in the chest roentgenogram. It offers a chance of early detection of primary lung cancer and subsequent resection with acceptable results.

Orosomucoid phenotyping with monoclonal antibodies:polymorphic occurrence of ORM1*Q0 in aboriginal Taiwanese populations

Three monoclonal antibodies (OR35, OR40 and OR48) against orosomucoid (ORM) were prepared for the phenotyping of the human ORM system. The OR35 and OR48 antibodies recognized ORM1 and ORM2 products, respectively. OR40 reacted strongly to the products of ORM1 but poorly to those of ORM2. With the help of these monoclonal antibodies, ORM phenotyping was performed on 658 individuals from nine subpopulations of aboriginal Taiwanese, with close attention to two individuals with an ORM1 Q0 homozygous phenotype. The ORM1*Q0 allele was found to be at a polymorphic frequency in eight of the nine subpopulations.

Involvement of annexin-I in glucose-induced insulin secretion in rat pancreatic islets

Annexin-I was demonstrated to specifically present in islets and not in exocrine tissues of the rat pancreas and to have a diffuse and homogeneous distribution in all islet cells in our previous study. In the present report, to clarify the functions of annexin-I in rat pancreatic islets, especially in beta-cells, we investigated the role of annexin-I in insulin secretion. Immunoelectron microscopic analysis of pancreatic beta-cells demonstrated that immunogold particles reactive to annexin-I were almost exclusively observed on most of the insulin-containing granules (approximately 90%) and less frequently located in cytosol and other organelles, such as the endoplasmic reticulum and mitochondria. The number of annexin-I gold particles located on insulin granules after oral glucose administration was significantly increased compared with that observed in fasted rats. Moreover, when the isolated islets were stimulated by a high concentration of glucose (20 mM), the phosphorylation of annexin-I was markedly enhanced, and it was synchronized to insulin secretion. This phosphorylation mainly occurred on serine residues. H-7 (100 microM), a potent inhibitor of protein kinase-C, inhibited the phosphorylation to about 90%. These findings suggest that annexin-I might be involved in the regulatory mechanism of glucose-induced insulin secretion in rat pancreatic islets via phosphorylation-dephosphorylation processes.

p53 expression and DNA ploidy of cartilage lesions

The aim of this study was to investigate the expression of a tumor suppressor gene (p53) in cartilage lesions of bone and its relationship to their histological grade and DNA ploidy. An immunohistochemical assay for p53 and Feulgen-stained DNA preparations was subjected to computerized image analysis. Enchondromas, synovial chondromatosis, and low grade (grade I and II) chondrosarcomas were diploid. High grade (grade III) chondrosarcomas and high grade sarcomatous components of dedifferentiated chondrosarcomas were aneuploid. Well differentiated cartilaginous components of dedifferentiated chondrosarcomas were diploid. Microscopic examination showed weak focal positivity for p53 in one of 10 enchondromas one of six examples of synovial chondromatosis, and three of four low grade (grade I and II) chondrosarcomas. All three high grade (grade III) chondrosarcomas were strongly positive for p53. The high grade sarcomatous component of all four dedifferentiated chondrosarcomas was strongly positive for p53, whereas only focal weak positivity was noted in the well differentiated cartilaginous areas. These results were confirmed by quantitative computer-assisted image analysis, which showed that high grade aneuploid cartilage tumors demonstrated strikingly higher levels of p53 than did diploid low grade malignant tumors or benign cartilage lesions.

Tophaceous pseudogout (tumoral calcium pyrophosphate dihydrate crystal deposition disease)

Most cases of calcium deposition seen radiologically in soft tissues are caused by calcium hydroxyapatite and occur either as a complication of trauma with associated necrosis (eg, fat necrosis), generalized connective tissue diseases (eg, scleroderma), metabolic disturbances (eg, hyperparathyroidism, familial hyperphosphatemia), sarcoidosis, myeloma, or metastases. Hydroxyapatite deposits are seen at many soft tissue sites, including joint capsules, ligaments, blood vessels, dermis, etc. On the other hand, deposits of calcium pyrophosphate are seen typically in the meniscus, articular cartilage, ligamentum flavum, and intervertebral disc. They usually are punctate or linear in distribution within the meniscus or parallel to the subchondral bone end plate. We report seven cases of massive focal calcium pyrophosphate dihydrate (CPPD) crystal deposition disease (tophaceous pseudogout) that occurred in atypical locations for CPPD. The ages of the patients ranged from 31 to 86 years (average, 60.7 years). One patient was male and six were female. The temporomandibular joint was involved in three patients and the metatarsophalangeal joint of the great toe was involved in two patients. The hip joint and cervical spine were involved in one patient each. A mass or swelling with or without pain was a common symptom. None of the patients in our series had clinical or radiographic evidence of CPPD crystal deposition disease in any other joints. Roentgenograms showed calcified lesions with a granular or fluffy pattern. Histologically, the lesions showed small or large deposits of intensely basophilic calcified material containing needle shaped and rhomboid crystals with weakly positive birefringence characteristic of CPPD. Foreign body granulomatous reaction to the CPPD deposition was constantly found. Chondroid metaplasia around and in the areas of CPPD deposition was observed commonly. Some of the chondroid areas showed cellular atypia in chondrocytes suggestive of a malignant cartilage tumor. It is important to recognize this rare form of CPPD crystal deposition disease and to identify the CPPD crystals in the calcified deposits, thus avoiding the misdiagnosis of benign or malignant cartilaginous lesions.

[Gene expression of human eukaryotic initiation factor-4E for protein synthesis and study of its recognition mechanism of mRNA cap structure]

Being stimulated by the insights from model studies that (i) the intimate combination of hydrogen-bonding pairing and aromatic stacking interactions is important for the specific binding of guanine base by peptide and (ii) the pi-pi stacking force of Trp is significantly strengthened by the guanine N7-methylation (m7G), this research project was started, because (a) the mRNA cap structure is characterized by the existence of m7G and (b) an eukaryotic initiation factor-4E (eIF-4E), a protein which specifically recognizes the mRNA cap structure and opens the protein biosynthesis, contains 8 Trp residues irrespective of its relatively low molecular weight of about 25 kDa. In order to prepare the sufficient amount of sample for carrying out the analysis of the recognition mechanism of mRNA cap structure by eIF-4E at the atomic level, firstly, the expression of human eIF-4E gene in Escherichia coli was attempted. An artificial gene encoding for human eIF-4E was chemically synthesized and succeeded in the expression with two different forms, i.e., as a fusion protein with human growth hormone and a direct expression of soluble protein. The isolation of eIF-4E and its purification procedure using the m7GTP affinity chromatography were accomplished. It was shown by spectroscopic methods that the recombinant eIF-4E exhibits essentially the same tertiary structure as the native one and the binding ability with mRNA cap analog was identical with each other. In order to analyze the functional amino acid residues which are essential for specific recognition of mRNA cap structure, next a series of eIF-4E mutants were prepared by the site-directed mutagenesis, and His37, His200, Trp102 and Glu103 were suggested to be important for binding of mRNA cap structure, as judged from comparison of the binding abilities of respective mutants with a m7GTP affinity column. Since the crystals of recombinant eIF-4E-m7GTP complex suitable for X-ray crystallography are now in preparation, the detailed interaction mode between them will be opened in near future.