Synthesis and characterization of the sweet protein brazzein

The sweet protein brazzein isolated from the fruit of the African plant, Pentadiplandra brazzeana Baillon is 2000-500 times sweeter than sucrose and consists of 54 amino acid residues with four intramolecular disulfide bonds. Brazzein was prepared by the fluoren-9-yl-methoxycarbonyl solid-phase method, and was identical to natural brazzein by high performance liquid chromatography, mass spectroscopy, peptide mapping, and taste evaluation. The D enantiomer of brazzein was also synthesized, and was shown to be the mirror image of brazzein. The D enantiomer (ent-brazzein) was devoid of any sweetness and was essentially tasteless.

Crystallization and preliminary X-ray analysis of brazzein, a new sweet protein

Brazzein is a sweet protein isolated from a wild African plant Pentadiplandra brazzeana. Brazzein is the smallest (molecular mass = 6473 Da) and the most water-soluble protein sweetener discovered so far and is highly thermostable. Crystals were grown by vapor diffusion using sodium sulfate as a precipitant. They belong to the tetragonal space group I4(1)22 with unit-cell parameters a = b = 61.4, c = 59.6 A and with one molecule in the asymmetric unit. The crystals diffract to 1.8 A resolution using synchrotron radiation.

Assignment of the disulfide bonds in the sweet protein brazzein

The thermostable sweet protein brazzein consists of 54 amino acid residues and has four intramolecular disulfide bonds, the location of which is unknown. We found that brazzein resists enzymatic hydrolysis at enzyme/substrate ratios (w/w) of 1:100-1:10 at 35-40 degrees C for 24-48 h. Brazzein was hydrolyzed using thermolysin at an enzyme/substrate ratio of 1:1 (w/w) in water, pH 5.5, for 6 h and at 50 degrees C. The disulfide bonds were determined, by a combination of mass spectrometric analysis and amino acid sequencing of cystine-containing peptides, to be between Cys4-Cys52, Cys16-Cys37, Cys22-Cys47, and Cys26-Cys49. These disulfide bonds contribute to its thermostability.

Potent inhibitors of acyl-CoA:cholesterol acyltransferase. 2. Structure-activity relationships of novel N-(2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)amides

Novel N-(2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)amide derivatives 1 were synthesized and tested for their ability to inhibit rabbit small intestinal ACAT (acyl-CoA:cholesterol acyltransferase) and lower serum total cholesterol in cholesterol-fed rats. Among the synthesized compounds, N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl)amide derivatives showed potent ACAT inhibitory activity. The synthesis and structure-activity relationships of these compounds are described. A methyl group at position 6 of the 2,3-dihydrobenzofuran moiety was important for potent ACAT inhibitory activity. In the series of N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl) amides, lipophilicity of the acyl moiety was necessary for the potent ACAT inhibitory activity. The highly lipophilic acid amides N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl)-2,2- dimethyldodecanamide (10) and 6-(4-chlorophenoxy)-N-(2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-y l)-2,2-dimethyloctanamide (50) showed potent activity. Introduction of a dimethylamino group at position 5 of the 2,3-dihydrobenzofuran moiety resulted in highly potent activity. The most potent compound, N-[5-(dimethylamino)-2,2,4,6-tetramethyl-2,3-dihydrobenzofuran-7-yl ]-2,2-dimethyldodecanamide (13, TEI-6620), showed highly potent ACAT inhibitory activity (rabbit small intestine IC50 = 0.020 microM, rabbit liver IC50 = 0.009 microM), foam cell formation inhibitory activity (rat peritoneal macrophage IC50 = 0.030 microM), extremely potent serum cholesterol-lowering activity in cholesterol-fed rats (71% at a dose of 0.3 mg/kg/day po), and good bioavailability in fed dogs (Cmax = 2.68 microg/mL at 1 h, 10 mg/kg po).

[Proliferation and differentiation of human salivary gland adenocarcinoma cell line HSG]

The adenocarcinoma cell line derived from an intercalated ductal epithelium of a human salivary gland (HSG) proliferates autonomously mediated by an epidermal growth factor-(EGF)-like molecule with a molecular weight of 46 kDa and an EGF receptor (EGFR). The c-erbB2 protein, a member of EGFR family was also expressed in HSG cells and was involved in the growth signal pathway of HSG cells as well as EGFR. The autocrine growth is regulated by glucocorticoid and retinoic acid (RA) via their receptors. Retinoic acid receptor (RAR) of HSG cells revealed a transcriptional activity in vivo, and the heterodimerization between RAR and 9-cis retinoic acid receptor (RXR) is requisite for the binding with a specific DNA element termed RA response element in vitro. RXR alpha and RXR beta were cloned from HSG cells, and these RXRs, together with RAR, seemed to play a physiological role in RA signaling in vivo.

Proliferative signal transduction by epidermal growth factor (EGF) in the human salivary gland adenocarcinoma (HSG) cell line

We examined the proliferative signal transduction by EGF in HSG-AZA 3, a subclone of HSG cell line. The treatment of cells with EGF resulted in an increase in [3H]thymidine incorporation into DNA depending upon EGF concentrations. In addition, the nuclear proto-oncogene c-fos was rapidly induced by EGF. Moreover, EGF induced transient expression of EGF receptor mRNA followed by the de novo synthesis of EGF receptor protein. On the other hand, treatment of the cells with EGF occurred phosphorylation by tyrosine kinase comprised in the EGF receptor, autophosphorylation, followed by activation of MAP kinase. These results indicate that the proliferative response to EGF is modulated by the phosphorylation cascade mediating EGF receptor-associated tyrosine kinase and MAP kinase, and transient activation of c-fos protein is implicated in the cell proliferation.

Dopamine-derived endogenous 1(R),2(N)-dimethyl-6,7-dihydroxy- 1,2,3,4-tetrahydroisoquinoline, N-methyl-(R)-salsolinol, induced parkinsonism in rat: biochemical, pathological and behavioral studies

Dopamine-derived 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (salsolinol, Sal) and related compounds were examined for their selective neurotoxicity to dopamine neurons by injection into the rat striatum. Among salsolinol analogs examined, only N-methyl-(R)- salsolinol (NM(R)Sal) induced behavioral changes very similar to those in Parkinson's disease: hypokinesia, stiff tail, limb twitching at rest and postural abnormality. Biochemical analysis showed that after NM(R)Sal injection, NM(R)Sal itself and its oxidation product, 1-2-dimethyl-6,7-dihydroxyisoquinolinium ion (DMDHIQ+) accumulated in the striatum, and also in the substantia nigra definite amount of DMDHIQ+ was detected. Dopamine and noradrenaline were reduced in the striatum and more markedly in the substantia nigra, whereas serotonin and its metabolite were not affected. Morphological analysis revealed selective reduction of tyrosine hydroxylase (TH)-containing neurons in the substantia nigra after continuous NM(R)Sal administration in the striatum. These results demonstrate the selective cytotoxicity of NM(R)Sal to the dopamine neurons in the substantia nigra, and the possible involvement of this 6,7-dihydroxy-isoquinoline in the pathogenesis of Parkinson's disease is discussed.

Allele distribution of a VNTR polymorphism at D4S43 locus in the Japanese population

Allele frequencies for the VNTR locus D4S43 were determined in a Japanese population sample by the polymerase chain reaction. Nine different alleles containing 1-15 repeats of the basic 14 bp unit were observed in 156 unrelated Japanese. The most common allele was one repeat unit (62.82%), and the next common alleles were those with 11 (14.42%) and 7 repeat units (12.50%). We estimated that D4S43 locus has a heterozygosity index of 0.56, a mean exclusion chance of 0.32, a discrimination rate of 0.76, and a polymorphic information content of 0.52. No evidence of significant deviations from the Hardy-Weinberg equillibrium was found in the Japanese population data.

Automated DNA typing of ACTBP2: a comparison of allelic ladder with GS 2500 as internal marker

A comparison was made between the size values of the alleles measured by the internal size marker of Genescan (GS 2500) and the size values measured by an allelic ladder constructed by our laboratory in the application of Genescan software for the typing of the ACTBP2 system. The measurement by GS 2500 showed a greater than 2 bp divergence (SD = 0.893) while the measurement by the allelic ladder showed only 0.1 bp divergence (SD = 0.008). Thus in genotyping of ACTBP2 by Genescan software, the method presented here of using the allelic ladder as the size marker instead of GS 2500 is easier and more reliable.

Location of the disulfide bonds of the sweetness-suppressing polypeptide gurmarin

The sweetness-suppressing polypeptide gurmarin has been isolated from the leaves of Gymnema sylvestre and consists of 35 amino acid residues including three intramolecular disulfide bonds. The primary structure has already been determined. The positions of the disulfide bonds were located, by a combination of mass spectrometric analysis and sequencing of cystine-containing peptides obtained by thermolysin-catalyzed hydrolysis of gurmarin, to be at Cys3-Cys18, Cys10-Cys23, and Cys17-Cys33.

Mechanism of dimer formation of the 90-kDa heat-shock protein

This study describes the mechanism of homodimer formation of the 90-kDa heat-shock protein (HSP90). In eukaryotic cells, there are two HSP90 isoforms, alpha and beta, encoded by two separate genes. HSP90 alpha exists predominantly as a homodimer, HSP90 beta mainly as a monomer. Analysis by native PAGE revealed that bacterially expressed HSP90 alpha fused to glutathione S-transferase (GST) existed as a high-molecular-mass oligomer, and was converted to a homodimer following removal of the fusion enzyme by thrombin cleavage. A deletion mutant, HSP90 alpha D44-603, formed a monomer and an N-terminal truncated mutant, HSP90 alpha 533-732, existed as a dimer, indicating that the dimer-forming ability resides somewhere in the C-terminal 200 amino acids. Limited proteolysis of the C-terminal 200 amino acids of HSP90 alpha with chymotrypsin produced the C-terminal 16-kDa fragment (Met628/Ala629-Asp732) and its adjacent more N-terminal 13-kDa fragment (Val542-Tyr627/Met628). Size-exclusion HPLC and two-dimensional PAGE analyses demonstrated that these two chymotryptic fragments bound each other. The C-terminal 198 amino acids as well as the full-length form of HSP90 beta revealed a lower dimer-forming activity than HSP90 alpha. Expression of the chimeric proteins at the C-terminal 198 amino acids of the alpha and beta isoforms further indicated that the 16 amino acid substitutions locating between amino acids 561 and 685 account for the impeded dimerization of HSP90 beta. A leucine zipper motif (Met402-Leu423) was unlikely to be involved in the dimer formation. Taken together, these results indicate that the dimeric structure of HSP90 alpha is mediated by the C-terminal 191 amino acids and consists of duplicate interactions of the C-terminal region (Met628/Ala629-Asp732) of one subunit and the adjacent more N-terminal region (Val542-Try627/Met628) of the other subunit.

[A study on international prostate symptom score in the assessment of therapeutic effects and severity of symptoms due to benign prostatic hyperplasia]

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common disease among elderly men in Japan. Recently, various non-invasive treatment modalities have been developed, however the criteria for the diagnosis and therapeutic effects of BPH have not been established yet. World Health Organization sponsored International Prostate Symptom Score (I-PSS) was devised. The criteria, however, were limited to evaluate the frequency of the subjective symptoms of BPH. In addition, this criteria did not include the quality of life (QOL) score.

PATIENTS AND METHODS

We examined I-PSS and a new by modified symptom score for patients who underwent TUR-P.

RESULTS

The efficacy of TUR-P could be confirmed by I-PSS, however the criteria proposed in I-PSS and in our modified symptom score were shown to be inadequate to evaluate QOL, and to be not specific scale for BPH. It was demonstrated that objective findings such as peak flow rate, residual urine volume and prostate volume did not correlate with the QOL score, however each objective and subjective significantly improved after TUR-P.

CONCLUSION

These results suggested that further effort should be made to establish reliable criteria for the diagnosis and evaluation of therapeutic efficacy considering QOL in BPH patients.

Recurrent reversible rhabdomyolysis associated with hyperthermia and status epilepticus

A 6-year-old boy developed rhabdomyolysis following hyperthermia and status epilepticus with a diagnosis of severe myoclonic epilepsy of infancy. At 2 and 3 years of age, he had similar episodes. Each time he recovered completely in 3-4 weeks with conservative management, in spite of renal insufficiency and marked liver dysfunction. Several cases of recurrent myoglobinuria after intense exercise of generalized tonic-clonic convulsions were reported to have genetic errors of carbohydrate or lipid metabolism of muscle. In our patient, however, the activity of these enzymes was found to be normal. This indicates that status epilepticus may cause recurrent rhabdomyolysis in subjects with normal glycolytic and lipolytic enzyme activity.

Potent inhibitors of acyl-CoA:cholesterol acyltransferase. Structure-activity relationships of novel N-(4-oxochroman-8-yl)amides

Novel N-(4-oxochroman-8-yl)amide derivatives 1 were synthesized and tested for their ability to inhibit rabbit small intestinal ACAT (acyl-CoA:cholesterol acyltransferase) in vitro and to lower serum total cholesterol in cholesterol-fed rats in vivo. Among the synthesized compounds, N-(7-alkoxy-4-oxochroman-8-yl)amide derivatives showed potent ACAT inhibitory activity both in vitro and in vivo. The structure-activity relationships of these N-(4-oxochroman-8-yl)amides and related compounds are discussed on the basis of these two assays. The carbonyl group at position 4 of the 4-chromanone was essential for potent ACAT inhibitory activity. N-(Chromon-8-yl) derivatives were less potent than N-(4-oxochroman-8-yl) derivatives. An alkoxy group at position 7 of the 4-chromanone moiety was important for potent ACAT inhibitory activity. In the N-(7-alkoxy-4-oxochroman-8-yl)amide derivatives, another necessary factor to elicit the potent ACAT inhibitory activity was lipophilicity of the molecules. The highly lipophilic acid amides N-(7-methoxy-4-oxochroman-8-yl)-2,2-dimethyldodecanamide (35) and 4-[[6-(4-chlorophenoxy)hexyl]oxy]-N-(7-methoxy-4-oxochroman-8- yl)benzamide (63) showed potent activity. Introduction of a highly lipophilic alkoxy group at position 7 of the 4-chromanone moiety instead of methoxy group also resulted in potent activity. In this case, highest inhibitory activity was obtained by N-[7-(decyloxy)-4-oxochroman-8-yl]-2,2-dimethylpropanamid e (65). The most potent compound, N-(7-methoxy-4-oxochroman-8-yl)-2,2-dimethyldodecanamide (35, TEI-6522), showed significant ACAT inhibitory activity (rabbit small intestine IC50 = 13 nM, rabbit liver IC50 = 16 nM), foam cell formation inhibitory activity (rat peritoneal macrophage IC50 = 160 nM), and extremely potent serum cholesterol-lowering activity in cholesterol-fed rats (61% at a dose of 0.1 mg/kg/day po).

Immunohistochemical study on collagenous proteins and biophysical analysis of crystals in extraskeletal chondroma

The immunohistological distribution of collagen types I, II, III, and VI in five cases of extraskeletal chondroma was examined and compared with that in six cases of enchondroma. In addition, the composition of crystals deposited in three cases of extraskeletal chondroma were biophysically analyzed with special attention to the relationship between the collagen types of the matrix and the crystal deposition. In extraskeletal chondroma, immunoreactivity of type II collagen in the extracellular matrix and type VI collagen in the pericellular area, which were strongly and diffusely recognized in the normal hyaline cartilage and enchondroma, was diminished. Instead, additional types of collagen, types I and III, were demonstrated in the matrix. Electron roentgenographic microanalysis and infrared light spectroscopic analysis revealed that calcium pyrophosphate dihydrate (CPPD) was included in the crystals of extraskeletal chondroma. CPPD crystals were observed in/around collagen types I and III. The possible relationship between the difference of collagen composition in the matrix and the CPPD crystal deposition is discussed.

Desk-top analysis of the structural stability of various point mutations introduced into ribonuclease H

The structural stability of Escherichia coli ribonuclease HI mutants was analyzed by a pseudo-energy potential developed for evaluating structure-sequence compatibility. From the structure profile, the energy changes of the folding of mutant proteins relative to that of the wild-type, which correspond to the changes of free energy differences, were estimated. They are weakly but significantly correlated with the experimentally determined changes in the melting temperature between the mutant proteins and the wild-type. The correlation coefficient between the experimental data and the computation, estimated for all the known data (96 point mutations) and for the buried site data (32 point mutations), are -0.51 and -0.68, respectively. Experimentally known mechanisms to increase the structural stability are explained by the method: the main contributor to the stability in mutations of Val74 to either Ile or Leu is the side-chain packing energy, and that of Lys95 to Gly is the local conformational energy. This analysis is easy to do on a desk-top computer, and allows one to consider all the sites of possible candidates for point mutations. From the profile, new promising sites to increase the structural stability are suggested.

[A case of multiple liver metastasis from remnant gastric cancer responding to leucovorin.5-FU+UFT therapy]

We report a case of a 67-year-old male patient who experienced multiple liver metastasis 6 months after undergoing an operation for remnant gastric cancer. The histological classification of the cancer in gastric remnant was poorly-differentiated adenocarcinoma. The patient was treated with a low dose of LV.5-FU once a week and oral UFT as an outpatient. As a result, after 3 months of the treatment, CT showed that multiple liver lesions almost disappeared, a condition that lasted about 3 years without relapse. Toxic effects due to this treatment were temporary slight liver disfunction, mild anorexia and stomatitis. This case indicates that the regimen of LV.5-FU+UFT may be effective for multiple liver metastasis from postoperative remnant gastric cancer, enabling the patient to maintain an excellent QOL (quality of life).

[Continuous intraarterial infusion of 5-fluorouracil plus leucovorin for liver metastases from colorectal cancer]

Between September 1990 and August 1994, 11 patients (pts) with liver metastases (mets) from colorectal cancer were treated with continuous hepatic arterial infusion chemotherapy of 5-fluorouracil (FU) plus leucovorin (LV). Eight pts had non-resectable liver mets (H3: 7, H2: 1), and 3 had residual small mets after resection of major mets. Drugs were administered via an extracorporeal infusion device connected to the hepatic arterial infusion port. 5-FU and LV were given through a 5- to 7-day continuous infusion at 500-750 mg/body/day and 30 mg/body/day, respectively, with a 3- to 4-week rest period. In the recent 6 pts, cisplatin was administered as a 2-hour infusion at 25 mg/body, one or two times simultaneously. Grade 2 toxicity was noted in two pts (18%). One was stomatitis and another was uncontrolled ascites in an advanced cirrhotic pt. The response rate in the 9 evaluable pts was 67% with 6 PR and no CR. The duration of the response was 5 to 9 months. One- and two-year survival rates were 75% and 22%, respectively. These results were superior to those of the intermittent bolus injection of 5-FU plus MMC (or epirubicin) in 40 pts from 1977 to 1994. These results suggest that continuous 5-FU plus LV arterial infusion is an effective regimen in pts with liver metastases from colorectal cancer. However, the infusion with an extracorporeal device limits the pts' quality of life. Further investigation is needed for a schedule that can be practiced for a longer period.

Proteus syndrome with renal involvement

We report on a case of an 11 year old girl with Proteus syndrome involving both kidneys morphologically and functionally. The patient had hemihypertrophy, scoliosis, overgrowth of lower extremities, partial macrodactyly, subcutaneous lipoma, and pigmented nevi compatible with the Proteus syndrome. She also had overgrowth of the right kidney with mildly impaired function and a small left kidney with severe dysfunction. Morphological involvement of visceral organs has previously been described; however, deteriorating renal function has not previously been reported in this syndrome.

Reduction of androgen receptor mRNA concentration by testosterone in mouse submandibular gland

In this study, we examine the effect of testosterone on the steady-state concentration of androgen receptor (AR) mRNA of mouse submandibular gland. Northern blot analysis showed the expression of an AR-specific 10-kb transcript in the submandibular glands of both sexes. Quantitative analysis was done by means of reverse transcription-polymerase chain reaction (RT-PCR) with a non-radioactive label of digoxigenin. The RT-PCR demonstrated that the steady-state of AR mRNA concentration was less in males than in females. Moreover, AR mRNA increased in the castrated male mice, while the administration of testosterone reduced the AR mRNA in female mice. In conclusion, the amount of AR mRNA in mouse submandibular gland is reduced by androgen.

[Interferon treatment for chronic hepatitis C--assessment of 3 regimens in patients received more than 500MU interferon treatment and their effect predictive factors for interferon treatment using multivariate analysis with the logistic regression model]

Chronic hepatitis C patients (n = 115) were treated with interferon (IFN). Total dose employed was more than 500 MU. The response rate was assessed among the three treatment groups: 2W continuous+TIW, 4W continuous+TIW, 8W continuous+TIW. The IFN treatment effect predictive factors were also assessed. Complete response (CR) rate, CR with serum HCV-RNA disappearance rate, responders' histology activity index score changes between before and after treatment, and responders' hepatocytes HCV-RNA disappearance rate did not differ among the three treatment regimens. CR to IFN treatment was dependent on serum HCV-RNA and HCV serotype. Patients of low serum HCV-RNA and serotype II were responsive to IFN treatment.