Subarachnoid hemorrhage from intracranial dissecting aneurysms of the anterior circulation. Two case reports

Two rare cases of intracranial dissecting aneurysms of the anterior circulation associated with subarachnoid hemorrhage (SAH) are described. A 56-year-old female presented with a dissecting aneurysm in the proximal segment of the left middle cerebral artery. Proximal occlusion of the affected artery and a superficial temporal artery-middle cerebral artery anastomosis were performed, but the outcome was poor. A 61-year-old male presented with a dissecting aneurysm in the proximal segment of the left anterior cerebral artery. Clipping was enhanced by a piece of fascia lata, allowing patency of the affected artery with a satisfactory outcome. Dissecting aneurysm of the carotid system should be considered in a patient with SAH but no evidence of berry aneurysm.

Nucleotide sequence of a cDNA encoding a common precursor of disintegrin flavostatin and hemorrhagic factor HR2a from the venom of Trimeresurus flavoviridis

The venom of Trimeresurus flavoviridis has three disintegrins that act as platelet aggregation inhibitors by binding to integrin alphaIIb beta3 on platelets through its Arg-Gly-Asp sequence. We isolated the cDNA encoding the flavostatin precursor that is one of the disintegrins in T. flavoviridis venom. The open reading frame consisted of four regions, a pre-peptide region, a metalloprotease region, a spacer region and a disintegrin region, indicating that the flavostatin precursor belongs to the metalloprotease/disintegrin family. Surprisingly, the deduced amino acid sequence of the metalloprotease region was completely consistent with that of hemorrhagic metalloprotease HR2a, which indicated that this metalloprotease released from the flavostatin precursor functions as a hemorrhagic factor. These observations indicated that a disintegrin and a hemorrhagic metalloprotease were synthesized as a common precursor. Thus, our results support the hypothesis that a disintegrin is synthesized as a metalloprotease/disintegrin precursor and matures by cleavage from the precursor molecule.

The effects of a walking exercise program on physical function and emotional state of elderly Korean women

Exercise is an important strategy for preventing chronic diseases and promoting the health of older adults. The purpose of this research was to evaluate the effects of an outdoor walking exercise program on the cardiorespiratory function, the flexibility, and the emotional state of elderly Korean women. A nonequivalent control group, pretest-posttest design was used to measure the effects of the exercise program. The subjects were 27 females between the ages of 60 to 75 years. The intensity of the walking program was 40-60% of the target heart-rate with a duration of 50-60 min, 3 times per week at an outdoor track for 8 weeks. The effects of the program were assessed by maximal oxygen uptake (VO2max), resting pulse rate, blood pressure Forced Vital Capacity (FVC), Forced Expiratory Volume per 1 second (FEV1) for cardiorespiratory function, the "sit and reach test" for flexibility, and by the Profile of Mood States (POMS) for emotional state. The physical function and the emotional state of the experimental group improved significantly more than that of the control group except FEV1 and the anger factor of POMS. The VO2max and the flexibility of elderly women in the experimental group progressively improved as the duration of the exercise period continued. The results of this study suggest a practical and easy method of exercise to enhance the health of older women.

Signal transduction pathways mediated by glycoprotein Ia/IIa in human platelets: comparison with those of glycoprotein VI

Human platelets were activated either by glycoprotein (GP) Ia/IIa agonist (rhodocytin) or by a GPVI agonist (collagen-related peptide, CRP), and the intracellular signal transduction pathways were compared in the presence of various inhibitors. Rhodocytin isolated from Calloselasma rhodostoma venom was verified as a GPIa/IIa agonist, based on the inhibitory effects of three mAbs directed against GPIa. Platelet activation mediated by GPIa/IIa led to overt platelet aggregation, elevation of intracellular Ca2+, and tyrosine phosphorylation of several proteins, similar to that of GPVI. p72(syk) and phospholipase Cgamma2 (PLCgamma2) tyrosine phosphorylation were also observed with GPIa/IIa-mediated platelet aggregation, although they peaked slightly later than that of GPVI. In contrast to GPVI-mediated platelet activation, most of these phenomena induced by GPIa/IIa activation were markedly suppressed by acetylsalicylic acid (ASA) or cytochalasin D. These findings suggest that the requirements for thromboxane A2 (TXA2) production and actin polymerization, which are the characteristics of collagen-induced platelet activation, are derived from the GPIa/IIa-mediated signal transduction, but not from that of GPVI.

Clinical course of atopic dermatitis in Japanese patients

We conducted a questionnaire study of 117 patients, who had first consulted the Department of Dermatology Kumamoto University Hospital 20 or 30 years ago, regarding the clinical course of atopic dermatitis (AD). Forty-one patients responded to the questionnaire. Seventeen patients (41.4%) had recovered and 24 patients (58.6%) still had AD. The AD had resolved in 12 of 13 (92.2%) with mild disease severity, four of 18 (22.2%) with moderate severity and one of ten (10%) with severe disease. The outcome was significantly better in the mild group than in the moderate or severe group (chi2=15.5, P=0.0008/chi2=14.8, P=0.00012, respectively). The resolution of the disease was not correlated with the sex of patient, age at onset, period of disease or family history.

Structural modification of an orally active thrombin inhibitor, LB30057: replacement of the D-pocket-binding naphthyl moiety

An amidrazonophenylalanine derivative LB30057 (2) was identified as a potent (Ki = 0.38 nM), selective, and orally active thrombin inhibitor. As a continuation of studies into benzamidrazone-based thrombin inhibitors, we have structurally modified compound 2 by replacing the naphthyl group with a variety of hydrophobic moieties. This study led to discovery of several compounds with significantly enhanced potency in thrombin inhibition without sacrificing selectivity against trypsin and oral absorption. The highest activity was obtained with compound 23 (Ki = 0.045 nM).

Rhodocytin, a functional novel platelet agonist belonging to the heterodimeric C-type lectin family, induces platelet aggregation independently of glycoprotein Ib

We isolated and characterized a functionally novel platelet agonist, designated as rhodocytin, from the Calloselasma rhodostoma venom. Rhodocytin was a disulfide-linked heterodimer consisting of 18- and 15-kDa subunits. The respective N-terminal amino acid sequences of both subunits were homologous to each other and to those of the carbohydrate-recognition domains (CRD) of C-type lectins. Rhodocytin alone induced platelet aggregation. Platelet agonists and antagonists constructed with CRD-like subunits from snake venoms bind to glycoprotein Ib directly or indirectly. However, rhodocytin induced platelet aggregation not by binding to glycoprotein Ib, because rhodocytin-induced platelet aggregation was not influenced by echicetin, a glycoprotein Ib-binding protein, that completely inhibits platelet agglutination by bovine von Willebrand factor. These findings indicate that rhodocytin is a novel protein structurally related to heterodimers of CRD-like subunits, but functionally distinct from venom proteins that induce platelet aggregation via glycoprotein Ib.

Photoaffinity labeling of D1 and D5 dopamine receptors

Although human D1 and D5 dopamine receptors are encoded by distinct genes and share only 50% sequence homology at the amino acid level, their pharmacological properties are identical. Using a selective D1 receptor photoaffinity radioligand, (+/-)-7-[125I]iodo-8-hydroxy-3-methyl-1-(4-azidophenyl)-2,3,4,5-tetrahyd ro-1H-3-benzazepine ([125I]MAB), we have further probed the molecular properties of these receptors in transfected GH4C1 rat pituitary cells. Under reversible, non-covalent binding conditions, [125I]MAB bound to both the D1 and the D5 receptors with identical affinities, dopaminergic selectivity and stereospecificity. Upon photoactivation of the bound [125I]MAB, the label was incorporated into a approximately 64,000 mol. wt protein corresponding to the D1 dopamine receptor. However, there was no specific photoincorporation of the ligand observed in D5 receptors. The lack of [125I]MAB photolabeling of D5 receptors was independent of the cell line chosen, since similar results were obtained using other transfected cells. The data suggest that although both D1 and D5 receptors share structurally similar binding sites, the protein domains around the sites are different. Thus, although there are currently no specific compounds which bind preferentially to D1 or D5 receptors, these receptors can be distinguished from one another by the inability of [125I]MAB to photolabel D5, but not D1, receptors. Such selective targeting of a specific receptor may be useful in understanding the functional importance and/or interaction between closely related members of the same receptor family when co-expressed in the same cell.

Discovery of LB30057, a benzamidrazone-based selective oral thrombin inhibitor

Systematic variation of the so-called P-pocket moiety of benzamidrazone-based selective thrombin inhibitors led to the discovery of LB30057. It is potent (Ki = 0.38 nM for human thrombin), selective (Ki = 3290 nM for bovine trypsin), and orally bioavailable (58% oral bioavailability in dogs). LB30057 was efficacious in thrombosis animal models.

Loperamide: a positive modulator for store-operated calcium channels?

The depletion of inositol trisphosphate-sensitive intracellular pools of calcium causes activation of store-operated calcium (SOC) channels. Loperamide at 10-30 microM has no effect on intracellular calcium levels alone, but augments calcium levels in cultured cells when SOC channels have been activated. In HL-60 leukemic cells, the apparent positive modulatory effect of loperamide on SOC channels occurs when these channels have been activated after ATP, thapsigargin, or ionomycin-elicited depletion of calcium from intracellular storage sites. Loperamide has no effect when levels of intracellular calcium are elevated through a mechanism not involving SOC channels by using sphingosine. Loperamide caused augmentation of intracellular calcium levels after activation of SOC channels in NIH 3T3 fibroblasts, astrocytoma 1321N cells, smooth muscle DDT-MF2 cells, RBL-2H3 mast cells, and pituitary GH4C1 cells. Only in astrocytoma cells did loperamide cause an elevation in intracellular calcium in the absence of activation of SOC channels. The augmentation of intracellular calcium elicited by loperamide in cultured cells was dependent on extracellular calcium and was somewhat resistant to agents (SKF 96365, miconazole, clotrimazole, nitrendipine, and trifluoperazine) that in the absence of loperamide effectively blocked SOC channels. It appears that loperamide augments influx of calcium through activated SOC channels.

Screening for galactosaemia in Greece

Galactosaemia appears to be one of the most appropriate disorders for routine newborn screening as almost normal outcome can be achieved in most of the identified cases. Galactose and galactose-1-phosphate were determined using Guthrie cards in a commercial kit based on a colorimetric microassay. Among 199,642 newborns, nine cases with classic galactosaemia, three with epimerase deficiency, six with compound Duarte2/heterozygotes for galactosaemia and four with compound2 Duarte homozygosity were found. Even though the number found among the screened neonates is small because it is such a rare disease, our results indicate one of the highest frequencies of the disease ever reported.

Tissue reactions to various percutaneous materials with different surface properties and structures

Tissue responses to various percutaneous materials with different surface properties and structures were investigated. Dense hydroxyapatite (HA), tricalcium phosphate (TCP), glassy carbon (GC), and 2 types of porous HA were used. Cutaneous and subcutaneous tissues were tightly attached to the surface of the penetrating portion of an HA percutaneous device (PD). Neither bacterial infection nor serious epidermal downgrowth were observed in the area surrounding the shaft of the HA-PD. At the margin of the epidermis, fibroblasts and collagen fibrils of fibrous connective tissue were well oriented and formed perpendicular to the shaft. The tissue response to the TCP was mild and nearly the same as that to the HA. The GC induced serious epidermal downgrowth and inflammatory cell infiltration. In contrast to dense HA-PD, the insertion of both types of porous HA-PDs, 1 with a spongy structure and 1 with close pores was followed by acute infection within 1 month. Based upon these results, it was concluded that the dense HA was the best percutaneous material of those tested.

A high-risk group for prostatism: a population-based epidemiological study in Korea

OBJECTIVE

To evaluate the effect of sociodemographic, dietary and physical factors on prostatism in Korean men aged 50 and over.

SUBJECTS AND METHODS

A community-based cross-sectional epidemiological study was performed in Yonchon County, Korea. The Korean version of the International Prostate Symptom Score (IPSS) was used to assess the severity of prostatism. Data on occupation, marital status, education, smoking habits, alcohol intake, daily consumption of nutrients, body mass index, abdominal circumference, waist-to-hip ratio, blood pressure, serum glucose, cholesterol, triglyceride and high-density lipoprotein (HDL) levels were analysed. The age-adjusted relative risk of these factors was calculated for moderate to severe prostatism (IPSS > or = 8). A multivariate analysis of all significant factors was performed to examine the joint effect of risk factors.

RESULTS

Of 514 subjects, 119 (23.2%) had moderate to severe prostatism, the risk for which was related to age and alcohol consumption; waist-to-hip ratio (which represents the degree of abdominal obesity) and the serum level of HDL showed a biphasic association with prostatism in the multivariate analysis.

CONCLUSION

In addition to previously reported risk factors, these data suggest that there might be an association between the development of prostatism and abnormal lipid metabolism.

Escherichia coli F1-ATPase subunit interactions: beta and gamma subunit peptides inhibit in vitro reconstitution of the active alpha beta gamma complex

For biochemical analysis of subunit interactions in the proton-translocating ATPase, a new approach with in vitro reconstitution of the Escherichia coli alpha beta gamma complex and the peptides derived from the subunits was established. Various portions of the beta or gamma subunits were used for in vitro reconstitution of the alpha beta gamma complex from the purified subunits. For the beta subunits, peptides corresponding to residues 226-459, 254-459, and 226-365 inhibited reconstitution, while those corresponding to residues 1-105, 1-146, and 295-459 did not. For the gamma subunits, peptides corresponding to residues 1-192 and 74-286 exhibited inhibitory effect on reconstitution, but the peptide containing residues 191-286 did not. Only inhibitory peptides blocked the assembly of the alpha beta gamma complex which was detected by nondenaturing polyacrylamide gel electrophoresis. These inhibitory peptides bound to the alpha or beta subunit on the filter, but the noninhibitory peptides did not. These results suggested that regions beta 254-294 and gamma 74-190 have sequences important for subunit interactions which interfered with those in the reconstitution mixtures. Based on comparison between X-ray crystallographic data of bovine alpha beta gamma complex and the present results, we discussed here the significance of the biochemical approach adopted in this study.

Spiropyrrolizidines: a new class of blockers of nicotinic receptors

The spiropyrrolizidine oximes 236 and 222 and a related spiropyrrolizidine alkaloid, nitropolyzonamine, block nicotinic receptor channels in rat pheochromocytoma PC12 cells and in human medulloblastoma TE671 cells. In PC12 cells with an alpha 3 beta 4(5)-nicotinic receptor, both the spiropyrrolizidine oxime 236 and nitropolyzonamine had IC50 values of about 1.5 microM, while spiropyrrolizidine oxime 222 had an IC50 value of 2.6 microM versus carbamylcholine-elicited sodium-22 influx. In TE671 cells with an alpha 1 beta 1 gamma delta nicotinic receptor, the spiropyrrolizidine oximes 236, 222, and nitropolyzonamine had IC50 values of 9.5, 14, and 67 microM, respectively. The inhibitions by the spiropyrrolizidine oxime 236 and nitropolyzonamine appeared to be noncompetitive in nature in both cell lines. In rat cerebral cortical membranes, binding of [3H]nicotine to alpha 4 beta 2 nicotinic receptors was not inhibited significantly by 10 microM concentrations of the spiropyrrolizidine oxime 236, or by nitropolyzonamine, as expected for a noncompetitive blocker. Both compounds at 10 microM had marginal effects on a variety of central receptors, but did inhibit binding of [3H]1,3-di(2-tolyl) guanidine to sigma receptors in mouse brain membranes with IC50 values of about 0.5 microM. The spiropyrrolizidine oxime 236 at 10 microM had no effect on batrachotoxin-elicited sodium influx in guinea pig cerebral cortical synaptoneurosomes or on ATP-elicited calcium influx in PC12 cells. Such spiropyrrolizidines represent a new structural class of blockers of nicotinic receptor channels with selectivity for ganglionic-type receptors.

Interactions of the F1-ATPase subunits from Escherichia coli detected by the yeast two-hybrid system

Subunit interactions among the F1-ATPase subunits were studied by the yeast two-hybrid system. Various pairwise combinations of genes encoding alpha, beta, gamma, delta and epsilon subunits of Escherichia coli H+-ATPase fused to the DNA-binding or activation domain of the yeast GAL4 gene were introduced into yeast and expression of a reporter gene encoding beta-galactosidase was detected. Combinations of the alpha and beta subunit genes, and of the epsilon and gamma subunit genes showed high levels of reporter gene expression, while those of alpha and delta, beta and delta, gamma and delta, and delta and epsilon demonstrated weak but significant reporter gene expression. However, combinations of alpha and gamma, beta and gamma, alpha and epsilon, and beta and epsilon did not induce reporter expression. None of the fused genes alone induced reporter gene expression. These results suggested that specific and strong interactions between the alpha and beta, gamma and epsilon, and weak interactions between the alpha and delta, beta and delta, and gamma and delta subunits occurred in yeast cells in the two-hybrid system. Effects of previously identified mutant beta subunits with Leu-40 to Pro. Glu-41 to Lys or Pro-332 to Gln substitutions which caused defects in molecular assembly of F1-ATPase were analyzed with regard to alpha-beta interactions. No interaction of the alpha and beta subunits was observed in this system using the beta subunit with mutation of Pro-332 to Gln. However, for the other two mutations, alpha-beta interactions were observed. This system may be useful for isolating mutants which have defects in interaction of F1-ATPase subunits.

Reconstitution of the F1-ATPase activity from purified alpha, beta, gamma and delta or epsilon subunits with glutathione S-transferase fused at their amino termini

Systems for overexpression and purification of active alpha, beta and gamma subunits of Escherichia coli H(+)-ATPase were established. The alpha and beta subunits recovered as soluble form were purified by hydroxyapatite column chromatography. Since the gamma subunit was overexpressed as the insoluble form, this subunit was purified by polyacrylamide gel-electrophoresis containing sodium dodecyl sulfate. By subsequent denaturation of this subunit with guanidine hydrochloride and renaturation, the active gamma subunit for reconstitution of the F1-ATPase activity with the purified alpha and beta subunit was obtained. The delta and epsilon subunits which were fused to the carboxy terminus of glutathione S-transferase (GST) were overproduced and purified by affinity chromatography. These fused proteins (delta-GST and epsilon-GST) were incubated with the purified alpha, beta and gamma subunits and applied to affinity chromatography. The alpha beta gamma delta-GST and alpha beta gamma epsilon-GST complex were eluted specifically by addition of glutathione and exhibited high and low ATPase activity, respectively, with a subunit stoichiometry similar to that in the native F1-ATPase, indicating that active complexes could be reconstituted with the fused proteins. These results suggested that the amino-terminal ends of the delta and epsilon subunits are not involved in formation of the active complex. The fused epsilon-GST bound the gamma subunit strongly, and the alpha subunit weakly. The delta-GST bound the gamma subunit significantly, and the alpha and beta subunits very weakly.

A new variant of type IV glycogenosis with primary cardiac manifestation and complete branching enzyme deficiency. In vivo detection by heart muscle biopsy

Type IV glycogenosis (polyglucosan body disease) is a rare congenital autosomal recessive inherited disorder, caused by lack of the branching enzyme (amylo-1,4-1,6 transglucosidase). This deficiency leads to storage of abnormal glycogen (polyglucosan bodies) in the liver and other tissues. The clinical onset of the disease is insidious with non-specific gastrointestinal symptoms followed by progressive hepatic failure. Usually patients die due to hepatic cirrhosis within 4 years. Sometimes myopathy of the heart and skeletal muscle is also present. In these cases, the clinical onset is often later than in typical cases. We report on two brothers with primarily cardiac manifestation and late onset of the disease. The older one started to suffer from progressive dilated cardiomyopathy at the age of 18 years, presenting with severe heart failure, hepatosplenomegaly, ascites and peripheral oedema. He also demonstrated myopathy and muscular atrophy especially of the shoulder and lower limbs. Initially he improved on medical therapy, but one year later severe heart failure recurred followed shortly afterwards by sudden cardiac death. Right heart and skeletal muscle biopsies were performed while he was alive. These, as well as the autopsy, revealed massive accumulation of polyglucosan bodies. In both heart and skeletal muscle, complete branching enzyme deficiency could be proven. His 14-year-old brother showed similar clinical findings of mild dilated cardiomyopathy. His muscle biopsy also revealed polyglucosan body myopathy. Thus, in young patients presenting with congestive cardiomyopathy, type IV glycogenosis has to be considered in the differential diagnosis.

Maitotoxin-elicited calcium influx in cultured cells. Effect of calcium-channel blockers

Maitotoxin elicited a marked influx of 45Ca2+ into NIH 3T3 fibroblast cells. The influx was blocked by imidazoles (econazole, miconazole, SKF 96365, clotrimazole, calmidazolium) with IC50 values from 0.56 to 3 microM. Phenylalkylamines (verapamil, methoxyverapamil) and nitrendipine were less potent, and diltiazem was very weak. Among other calcium blockers, the diphenylbutylpiperidines fluspirilene and penfluridol, the diphenylpropylpiperidine loperamide, and the local anesthetic proadifen were quite active with IC50 values of 2-4 microM. The pattern of inhibition of maitotoxin-elicited calcium influx did not correspond to the ability of the agents to block elevation of calcium that ensues through calcium-release activated calcium (CRAC) channels after activation of phosphoinositide breakdown by ATP in HL-60 cells. The imidazoles did block CRAC channels, but fluspirilene, penfluridol, loperamide and proadifen were ineffective. Loperamide actually appeared to enhance influx of calcium via the activated CRAC channels. The imidazoles, in particular calmidazolium, caused an apparent influx of calcium and caused a stimulation of phosphoinositide breakdown in HL-60 cells.

A new inherited muscular disorder in Japanese quails (Coturnix coturnix japonica)

Thirteen adult mutant (LWC strain) Japanese quails (Coturnix coturnix japonica), between the ages of 8 and 60 weeks were examined for a progressive muscular disorder. The disorder, inherited as an autosomal dominant trait, was clinically apparent as early as 28 days of age; it was characterized by generalized myotonia, muscle stiffness, and muscle weakness. Affected birds were identified by their inability to lift their wings vertically upward and by their inability to right themselves when placed on their dorsum. Electromyographic studies in two mutant quails showed high-frequency repetitive discharges comparable to those of myotonic runs. These discharges persisted after nerve resection. The distinctive histopathologic changes in the various muscles examined were ring fibers, sarcoplasmic masses, and internal migration of sarcolemmal nuclei. A slight decrease in the size of type IIB muscle fibers and a slight increase in the size of type IIA fibers were observed in the M. pectoralis thoracicus of affected quails. In older affected birds, inter- and intrafascicular fatty infiltration with replacement of type IIB fibers by fat cells was seen in the pectoral muscles. Single fiber necrosis, nonspecific lymphorrages, and variations in the muscle fiber size and shape were also noted. The typical muscle lesions and multisystem involvement, which was manifested by testicular degeneration and atrophy in the male LWC specimens and bilateral lenticular cataracts in 6 of 13 affected mutant quails, suggest resemblance of this new inherited muscular disorder to myotonic dystrophy in man.

Detection of canine distemper virus nucleocapsid protein gene in canine peripheral blood mononuclear cells by RT-PCR

For a rapid diagnosis of canine distemper virus (CDV) infection, the reverse transcription-PCR (RT-PCR) was carried out to detect CDV nucleoprotein (NP) gene from canine peripheral blood mononuclear cells (PBMCs). Two sets of primers were targeted to two regions of NP gene of CDV Onderstepoort strain. The NP gene fragments were well amplified by the RT-PCR in each of the RNA extracts from Vero cells infected with 6 laboratory strains of CDV including Onderstepoort strain, and from PBMCs of a dog experimentally infected with CDV. The amplified NP gene was detected in 17 of 32 samples from dogs which were clinically suspected for CDV infection at veterinary hospitals. No RT-PCR product was found in 52 samples from healthy dogs including 40 specific pathogen free beagles vaccinated with an attenuated live virus-vaccine for CDV and 12 stray dogs. The RT-PCR provides a fast, sensitive, and supplementary method for the diagnosis of CDV infection in dogs.

Prevalence of diabetes and IGT in Yonchon County, South Korea

OBJECTIVE

To determine the prevalence of diabetes and impaired glucose tolerance (IGT) in Yonchon County of South Korea and to investigate their associated factors.

RESEARCH DESIGN AND METHODS

We performed a population-based cross-sectional study with random cluster sampling of residents > or = 30 years of age. Among the 3,804 residents sampled, a total of 2,520 participants had a standard 75-g oral glucose tolerance test and answered a detailed questionnaire. We also collected standard anthropometric data.

RESULTS

If the data for participants in the age range of 30-64 years were adjusted to the standard world population, the prevalence of diabetes was 7.2% and the prevalence of IGT was 8.9%. It was observed that the significant factors associated with diabetes were waist-to-hip circumference ratio, serum triglyceride levels, age, systolic blood pressure, family history of diabetes, and locality.

CONCLUSIONS

The prevalence of diabetes in Yonchon County was substantially higher than was previously suggested. The risk of diabetes increased with the increased central obesity and metabolic disturbances associated with insulin resistance.

Enhancement of Escherichia coli H(+)-ATPase caused by binding of monoclonal antibodies is attributed to structural changes of Leu-456 and Ser-440 in the alpha subunit

Five monoclonal antibodies against the alpha subunit of F1-ATPase from Escherichia coli alpha 104, alpha 105, alpha 107, alpha 109, and alpha 110 were prepared. The monoclonal antibodies alpha 104 and alpha 110 enhanced the F1-ATPase activity maximally to 1.6- and 1.7-fold that of the wild-type, respectively, while alpha 105 did not. Both antibodies bound to a peptide corresponding to the region between residues 354 and 513. Mutations in this region which caused reduced binding of the alpha subunit to the antibodies were identified at residues Ser-440, Leu-456, Leu-471, Leu-482, Met-483, and Ser-506 for alpha 104 and residues Ser-440, Leu-456, Leu-471, Asp-476, Leu-482, Met-483, and Ser-506 for alpha 110. These residues are possibly involved in the epitopes for the antibodies and are located close together on the surface of the alpha subunit. Among the mutations, Leu-456 to Pro and Ser-440 to Pro mutations caused increase of the F1-ATPase activity up to 1.9 and 1.2 times that of the wild-type, respectively, while Leu-471 to Pro mutation caused a defect in assembly of the F1-ATPase on the membrane. The other mutations caused no significant change in ATPase activity. These results suggested that Ser-440 and Leu-456 have an important role in regulating catalysis by the F1-ATPase, but that the neighboring residue Leu-471 has an important role in assembly of the F1-ATPase complex. It was also suggested that binding of the monoclonal antibodies alpha 104 and alpha 110 to residues Ser-440 and Leu-456 caused local conformational changes, leading to enhancing effects on F1-ATPase activity similar to the Ser-440 to Pro and Leu-456 to Pro mutations.

The health insurance system in Korea and its implications

The national health insurance system was introduced in Korea in 1977 and achieved universal coverage in July 1989. This article briefly describes the general features of the insurance scheme: coverage, management, benefit package, financing provision of medical services and method of reimbursement. Generally speaking, the system mirrors that of the German and Japanese experiences. Although the Korean health insurance system achieved universal coverage during a remarkably short time-span, there is much room for improvement. In this regard, the article also highlights the problems related to Korea's health insurance system and the attempts to improve equity and efficiency in both financing and provision of services.

Effects of the amphiphilic peptides mastoparan and adenoregulin on receptor binding, G proteins, phosphoinositide breakdown, cyclic AMP generation, and calcium influx

1. The amphiphilic peptide mastoparan is known to affect phosphoinositide breakdown, calcium influx, and exocytosis of hormones and neurotransmitters and to stimulate the GTPase activity of guanine nucleotide-binding regulatory proteins. Another amphiphilic peptide, adenoregulin was recently identified based on stimulation of agonist binding to A1-adenosine receptors. 2. A comparison of the effects of mastoparan and adenoregulin reveals that these peptides share many properties. Both stimulate binding of agonists to receptors and binding of GTP gamma S to G proteins in brain membranes. The enhanced guanyl nucleotide exchange may be responsible for the complete conversion of receptors to a high-affinity state, complexed with guanyl nucleotide-free G proteins. 3. Both peptides increase phosphoinositide breakdown in NIH 3T3 fibroblasts. Pertussis toxin partially inhibits the phosphoinositide breakdown elicited by mastoparan but has no effect on the response to adenoregulin. N-Ethylmaleimide inhibits the response to both peptides. 4. In permeabilized 3T3 cells, both adenoregulin and mastoparan inhibit GTP gamma S-stimulated phosphoinositide breakdown. Mastoparan slightly increases basal cyclic AMP levels in cultured cells, followed at higher concentrations by an inhibition, while adenoregulin has minimal effects. 5. Both peptides increase calcium influx in cultured cells and release of norepinephrine in pheochromocytoma PC12 cells. The calcium influx elicited by the peptides in 3T3 cells is not markedly altered by N-ethylmaleimide. 6. Multiple sites of action appear likely to underlie the effects of mastoparan/adenoregulin on receptors, G proteins, phospholipase C, and calcium.

Angiotensin and ANP secretion during chronically controlled increments in atrial pressure

The primary objective of this study was to determine whether angiotensin II (ANG II) has direct effects on the atrium to chronically stimulate the secretion of atrial natriuretic peptide (ANP) by actions that are independent of its vasoconstrictor and fluid-retaining effects that increase ANP secretion indirectly by raising atrial pressure. In five dogs, right atrial pressure (RAP) was controlled at approximately 5.5 mmHg above control levels for 8 days by employing an externally adjustable occluder around the pulmonary artery and a servo-control system, and plasma levels of ANG II were fixed at either normal (days 1-3 and 7-8) or high (days 4-6) physiological concentrations by chronic infusion of captopril+ANG II. When plasma ANG II was maintained at normal levels during servo-control of RAP, plasma ANP concentration increased five- to sixfold and sodium balance was achieved at a reduced arterial pressure (-14 mmHg). In contrast, despite increased plasma levels of ANP, the high rate of ANG II infusion produced marked sodium retention during the initial 24 h; however, the antinatriuresis was not sustained because the servo-control system partially deflated the pulmonary artery occluder to prevent fluid-induced increments in RAP. Moreover, in the absence of a change in RAP, high plasma levels of ANG II did not influence plasma ANP concentration. These findings indicate that the plasma levels of ANP achieved in heart failure increase renal excretory capability and allow fluid balance to be achieved at a substantial fall in mean arterial pressure as long as there is minimal involvement of the renin-angiotensin system.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ATP and UTP in pheochromocytoma PC12 cells: evidence for the presence of three P2 receptors, only one of which subserves stimulation of norepinephrine release

1. In pheochromocytoma PC12 cells ATP and, to a lesser extent, 2-methylthioATP stimulate phosphoinositide breakdown, release of intracellular calcium, and influx of external calcium, leading to stimulation of norepinephrine release. In contrast, although UTP also stimulates phosphoinositide breakdown, release of intracellular calcium, and influx of external calcium, there is no stimulation of norepinephrine release. 2. 2-MethylthioATP, presumably acting at P2y receptors, and UTP, presumably acting at P2u receptors, in combination elicit a phosphoinositide breakdown greater than that elicited by either alone. Intracellular levels of calcium measured with Fura-2 increase to greater levels with ATP than with UTP and are sustained, while the UTP intracellular levels of calcium rapidly return to basal values. Both ATP and UTP cause a similar influx of 45 Ca2+ presumably by stimulation of a P2 receptor directly linked to a cation channel. 3. It is proposed that PC12 cells contain two distinct G protein-coupled P2 receptors that activate phospholipase C and a P2 receptor linked to a cation channel. The P2y receptor sensitive to ATP (and to 2-methylthioATP) causes the depletion of a pool of intracellular calcium, sufficient to activate so-called "receptor-operated calcium entry". The sustained elevation of intracellular calcium after ATP treatment is proposed to result in stimulation of norepinephrine release and activation of calcium-dependent potassium channels and sodium-calcium exchange pathways. 4. The P2u receptor sensitive to UTP (and to ATP) causes only a transient elevation in levels of intracellular calcium, perhaps from a different pool, insufficient to activate so-called receptor-operated calcium entry. Further sequelae do not ensue, and the functional role of the UTP-sensitive P2u receptor is unknown.

Halogen-substituted trimetoquinol analogs as thromboxane A2 receptor antagonists in platelets and aorta

Trimetoquinol (TMQ) is a non-prostanoid compound that blocks prostaglandin H2/thromboxane A2 (TXA2) receptor-mediated responses initiated by a prostaglandin (PG) H2 analog, U46619, in human platelets and rat aorta. Ring fluorine-substituted TMQ analogs selectively antagonized PG-dependent human platelet activation induced by U46619, arachidonic acid, collagen, ADP or epinephrine; and were about 300-fold less potent as inhibitors of PG-independent responses mediated by thrombin or bacterial phospholipase C. For each inducer of the PG-dependent pathway, the rank order of inhibitory potency was identical (TMQ > 8-fluoro-TMQ > 5-fluoro- TMQ). Iodine substitution yielded a similar rank order of antagonism against U46619-induced platelet activation (TMQ > 8-iodo-TMQ > 5-iodo-TMQ), and all TMQ analogs inhibited platelet aggregation in whole blood as well as in platelet-rich plasma. Inhibition of specific [3H]SQ 29,548 binding by TMQ analogs was highly correlated with inhibition of functional responses to U46619. Radioligand binding experiments using TMQ analogs with rat platelets showed no interspecies difference in comparison with human platelets. The rank order of inhibitory potencies for the fluorinated (but not iodinated) TMQ analogs changed in rat thoracic aorta with 8-fluoro-TMQ > TMQ > or = 5-fluoro-TMQ as antagonists of U46619-induced vascular contraction. These findings demonstrate that the primary mechanism of antiplatelet action of TMQ analogs is related to a blockade of TXA2 receptor sites, and ring-halogenated TMQ analogs distinguish between TXA2-mediated functional responses in vascular smooth muscle and platelets.

Interactions of nonprostanoid trimetoquinol analogs with thromboxane A2/prostaglandin H2 receptors in human platelets, rat vascular endothelial cells and rat vascular smooth muscle cells

Trimetoquinol (TMQ), a nonprostanoid compound, inhibits thromboxane A2 agonist-induced responses in platelets and vascular smooth muscle. Sixteen TMQ analogs were used to examine the stereochemical requirements of the interaction with thromboxane A2/prostaglandin H2 (TP) receptor sites in human platelets (HP), and cultured rat vascular endothelial (RVEC) and smooth muscle (RVSMC) cells. [3H]SQ 29548 was used as the ligand for TP receptors. The receptor binding affinities of these TMQ analogs for TP receptors in HP, RVEC and RVSMC were highly correlated with each other, and to their reported inhibitory potency values against U46619-induced HP aggregation and serotonin secretion, and contraction of rat aorta. TP receptor binding affinities of TMQ and 8-fluoro TMQ isomers were highly stereoselective (R-isomer > S-isomer), and only the 8-fluoro TMQ isomers gave qualitatively different functional responses in rat aorta. The affinity of TMQ for TP receptors was increased by addition of iodine and fluorine atoms at the 5- and 8-positions of the catechol ring or by replacement of the methoxy groups with iodine atoms on the 1-benzyl ring system. The results indicate that: 1) the stereochemical requirements of TMQ analogs for interaction with TP receptors in these cell systems are the same; 2) although TMQ analogs act as TP receptor antagonists, differences in functional responses by 8-fluoro TMQ isomers in platelets and aorta are not explained by their relative binding affinities to TP receptors; and 3) asymmetric halogenated TMQ analogs should be useful as affinity probes for further characterization of TP receptors.

Long-term outcome in 134 patients with galactosaemia

In a retrospective study 134 galactosaemic patients, born between 1955 and 1989 in the Federal Republic of Germany were traced and their long-term outcome evaluated. We investigated 83 galactosaemic patients (78 homozygotes, 5 compound heterozygotes) by clinical, psychometric and laboratory testing; 31 patients were evaluated by medical history, the remaining 20 patients had died due to sequelae of the underlying disease. In 48 out of 78 classical galactosaemia patients galactose-free therapy had been started before the 15th day, in 19 between days 15 and 56 and in 11 patients after the 56th day. Physical findings revealed that puberty was delayed in 1 out of 18 males and 6 out of 11 females. Neurological abnormalities included ataxia (n = 6), intention tremor (n = 11) and microcephaly (n = 10). Speech abnormalities were found in 43 out of 66 patients over 3 years of age and disturbance of visual perception and/or arithmetic deficits in 29. Intelligence declined with age, i.e., a DQ or IQ less than 85 was found in 4 out of 34 patients less than 6 years of age (12%), in 10 out of 18 between 7 and 12 years (56%) and in 20 out of 24 older than 12 years (83%). Metabolite patterns (RBC galactose-1-phosphate and UDP-galactose, plasma and urinary galactitol) did not correlate with DQ or IQ. Dietary compliance was good in almost all patients. Compound heterozygotes (n = 5) had normal mental and growth development and all laboratory parameters were in the normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Spatially invariant image sequences

The authors define linearly additive spatially invariant image sequences and present an explicit mathematical model for describing them. In such a sequence, all objects are positionally invariant in each image of the sequence but have varying gray-scale contributions to the successive images of the sequence. The various components (features or processes) of the scene or object contribute additively to each image of the sequence, but each component has a characteristic variation (signature) from image to image due to the variation of the function, parameter or spectral band over the sequence. Objects with different spectral characteristics will have different image sequence signatures which can be used to distinguish them. Also presented are the general formulation, derivation, and explicit expression for the linear filter, called the simultaneous diagonalization (SD) filter, that calculates a single new image from the sequence such that a desired process is emphasized and any number of undesired processes is suppressed in the filtered image.

Hormonal and circulatory responses to chronically controlled increments in right atrial pressure

To study the time-dependent changes in the secretion of atrial natriuretic peptide (ANP) in response to chronic stimulation by controlled increments in atrial pressure, we developed methodology for precise control of right atrial pressure (RAP) in dogs by employing an externally adjustable occluder around the pulmonary artery and a servo-control system. During 7 days of servo-control of RAP at 6.3 +/- 0.1 mmHg above control levels (1.3 +/- 0.1 mmHg), the 24-h coefficient of variation in RAP was 1/45 the variation that occurred under control conditions. After 30 min of increased RAP, mean arterial pressure (MAP) was reduced from 101 +/- 4 to 84 +/- 3 mmHg in association with increments in plasma renin activity (PRA) from 0.6 +/- 0.1 to 2.5 +/- 0.9 ng angiotensin I (ANG I).ml-1.h-1 and in the plasma concentrations of ANP, arginine vasopressin (AVP), and epinephrine from 93 +/- 18 to 484 +/- 61 pg/ml, from 0.5 +/- 0.1 to 9.2 +/- 2.4 pg/ml, and from 82 +/- 27 to 585 +/- 133 pg/ml, respectively. In comparison, on day 7 of servo-control of RAP, sodium balance was achieved and MAP remained depressed (82 +/- 4 mmHg) along with sustained increments in both plasma ANP concentration (482 +/- 67 pg/ml) and PRA (1.7 +/- 0.6 ng ANG I.ml-1.h-1); on the other hand, the plasma concentrations of AVP and epinephrine returned to control levels. This quantitative study indicates that ANP secretion does not chronically adapt to stimulation by increased atrial pressure and suggests that the plasma levels of ANP achieved in heart failure markedly increase renal excretory capability and allow fluid balance to be achieved at a substantial fall in renal perfusion pressure.

Pharmacologic antagonism of thromboxane A2 receptors by trimetoquinol analogs in vitro and in vivo

Although (-)-(S)-trimetoquinol [1-(3,4,5-trimethoxy-benzyl)- 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline; TMQ] is recognized as a potent bronchodilator, (+)-(R)-TMQ is a selective antagonist of human platelet aggregation and serotonin secretion induced by thromboxane A2 (TXA2) agonists. To confirm the pharmacological actions of TMQ analogs, the interaction of the drugs with TXA2 receptors was examined in human platelets and in a mouse sudden death model. The inhibitory potencies of TMQ analogs (pIC50 values) for displacement of [3H]SQ 29,548 binding to platelets showed excellent correlation with the respective pIC50 (-log IC50) values for U46619-induced aggregation (r = 0.99, P less than 0.01) and serotonin secretion (r = 0.99, P less than 0.01) in human platelet-rich plasma and for whole blood aggregation (r = 0.99, P less than 0.01). In each system, the rank order of inhibitory potencies was rac-iodoTMQ greater than or equal to (+)-(R)-TMQ greater than rac-TMQ much greater than (-)-(S)-TMQ. Antithrombotic effects of TMQ analogs were evaluated in a mouse sudden death model. In vivo antithrombotic potencies of these compounds were consistent with the in vitro potencies as TXA2 receptor antagonists in platelet systems. Administration of rac-iodoTMQ, (+)-(R)-TMQ and rac-TMQ 15 min before the injection of U46619 (800 micrograms/kg, iv) protected mice against U46619-induced sudden death. On the other hand, (-)-(S)-TMQ did not protect animals against death. Protection of U46619-induced cardiopulmonary thrombosis by TMQ analogs was seen at doses of 3-100 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic effects of a physiological dose of ANP on arterial pressure and renin release

To determine the long-term effects of a physiological dose of atrial natriuretic peptide (ANP) on renin release, the renin response to reductions in renal arterial pressure (RAP) was studied during 1) control conditions and 2) acute and 3) chronic (5 days) intravenous infusion (5 ng.kg-1.min-1) of alpha-human ANP in conscious dogs maintained on a normal sodium intake. Renal perfusion pressure was servo controlled at reduced levels with an inflatable occluder placed around the abdominal aorta just above the renal arteries. Under control conditions, reducing RAP by 30 and 40 mmHg increased plasma renin activity (PRA) 4- to 5- and 9- to 10-fold, respectively. Acute ANP infusion had no significant effect on either basal levels of PRA or the PRA response to reduced RAP. During chronic ANP infusion there was a two- to threefold increment in plasma ANP concentration and approximately a twofold increase in urinary sodium excretion on day 1; however, there were no significant long-term changes in mean arterial pressure, basal PRA, or the levels of PRA achieved during reductions in RAP. These findings indicate that the changes in plasma ANP concentration that occur under normal physiological conditions do not appreciably alter either basal PRA or renin release in response to renal hypotension in conscious sodium-replete dogs studied under resting conditions.