Granular corneal dystrophy with homozygous mutations in the kerato-epithelin gene

PURPOSE

To report a family with several members affected with granular corneal dystrophy Groenouw type 1. Three members of the family were affected with a severe placoid type of corneal dystrophy. To determine the relationship between gene mutations and phenotypic variations of the disease, we analyzed the kerato-epithelin gene.

METHODS

The pedigree included a consanguineous marriage of two affected individuals. The three family members affected with a severe form of corneal dystrophy were offspring of these parents. However, the phenotype of other affected family members was typical granular corneal dystrophy. We isolated genomic DNA from leukocytes of the family members. Exons of the keratoepithelin gene were amplified by the polymerase chain reaction and were analyzed using the single-strand conformation polymorphism technique. Mutations were identified by direct sequencing method and restriction digestion analysis.

RESULTS

The three severely affected family members exhibited homozygous mutations at codon 555 (arginine to tryptophan) in the keratoepithelin gene, whereas those with typical granular corneal dystrophy had the heterozygous mutation at the same codon. Unaffected family members did not have the mutation.

CONCLUSIONS

We determined that the severe phenotype of granular corneal dystrophy is caused by homozygous mutations in the kerato-epithelin gene. Clinical manifestation of the severe phenotype is a placoid type of corneal dystrophy and early recurrence after surgery. Granular corneal dystrophy appears to be the first ophthalmic disease in which homozygosity for a dominant allele has been genetically identified.

Protective and preventive effects of teprenone on gastric mucosal lesions in rats

We have reported that neutrophil infiltration into gastric mucosa is closely related to gastric mucosal lesion development in rats with water immersion restraint stress. In this study, we examined the effect of teprenone, which is known to prevent gastric mucosal injury through stimulation of gastric mucus synthesis and secretion, on neutrophil infiltration into the gastric mucosa of rats with water immersion restraint stress. Pre- and post-administration of teprenone (200 mg/kg, p.o.) significantly attenuated the neutrophil infiltration into the gastric mucosa and the lesion development found at 6 h of water immersion restraint stress with preservation of gastric mucosal hexosamine and adherent mucus levels. These results indicate that teprenone exerts protective and preventive actions against water immersion restraint stress-induced gastric mucosal lesions in rats and suggest that these actions could be related to the preservation of gastric mucus synthesis and secretion and inhibition of neutrophil infiltration into the gastric mucosal tissue.

Gab1 acts as an adapter molecule linking the cytokine receptor gp130 to ERK mitogen-activated protein kinase

Gab1 has structural similarities with Drosophila DOS (daughter of sevenless), which is a substrate of the protein tyrosine phosphatase Corkscrew. Both Gab1 and DOS have a pleckstrin homology domain and tyrosine residues, potential binding sites for various SH2 domain-containing adapter molecules when they are phosphorylated. We found that Gab1 was tyrosine phosphorylated in response to various cytokines, such as interleukin-6 (IL-6), IL-3, alpha interferon (IFN-alpha), and IFN-gamma. Upon the stimulation of IL-6 or IL-3, Gab1 was found to form a complex with phosphatidylinositol (PI)-3 kinase and SHP-2, a homolog of Corkscrew. Mutational analysis of gp130, the common subunit of IL-6 family cytokine receptors, revealed that neither tyrosine residues of gp130 nor its carboxy terminus was required for tyrosine phosphorylation of Gab1. Expression of Gab1 enhanced gp130-dependent mitogen-activated protein (MAP) kinase ERK2 activation. A mutation of tyrosine 759, the SHP-2 binding site of gp130, abrogated the interactions of Gab1 with SHP-2 and PI-3 kinase as well as ERK2 activation. Furthermore, ERK2 activation was inhibited by a dominant negative p85 PI-3 kinase, wortmannin, or a dominant negative Ras. These observations suggest that Gab1 acts as an adapter molecule in transmitting signals to ERK MAP kinase for the cytokine receptor gp130 and that SHP-2, PI-3 kinase, and Ras are involved in Gab1-mediated ERK activation.

Transforming growth factor beta2 in the vitreous in proliferative diabetic retinopathy

OBJECTIVE

To evaluate the hypothesis that transforming growth factor beta2 (TGF-beta2) is involved in the cause of proliferative diabetic retinopathy (PDR).

METHODS

We assayed TGF-beta2 levels in the vitreous of patients with PDR and other vitreoretinal disorders. Forty-nine vitreous specimens were obtained from eyes of patients with PDR undergoing vitrectomy, and 19 vitreous specimens from nondiabetic subjects served as controls. We assessed TGF-beta2 levels using an enzyme-linked immunosorbent assay. Both mature and total TGF-beta2 levels were quantified.

RESULTS

The mean (+/- SD) total levels of TGF-beta2 were 2634 (+/- 1652) pg/mL in the patients with PDR and 1305 (+/- 972) pg/mL in controls. The mean (+/- SD) levels of mature TGF-beta2 were 244 (+/- 316) pg/mL in patients with PDR and 79 (+/- 81) pg/mL in controls. Total and mature TGF-beta2 levels were significantly greater in patients with PDR (total TGF-beta2, P <.001; mature TGF-beta2, P <.01). Mature TGF-beta2 levels were higher in the vitreous of patients who had severe fibrous proliferation.

CONCLUSION

The results indicate increased levels of both total and mature TGF-beta2 in the vitreous of patients with PDR, suggesting that TGF-beta2 plays an important role in the pathogenesis of PDR.

Inhibitory effect of Oren-gedoku-to (Huanglian-Jie-Du-Tang) extract on hepatic triglyceride accumulation with the progression of carbon tetrachloride-induced acute liver injury in rats

The inhibitory effect of Oren-gedoku-to (Huanglian-Jie-Du-Tang) extract (TJ-15) on hepatic triglyceride (TG) accumulation with the progression of acute liver injury was examined in rats intoxicated with carbon tetrachloride (CCl4). TJ-15 at a dose of 100, 250 or 500 mg/kg body weight (BW) was orally administered to male Wistar rats aged 7 weeks, 6 h after the intraperitoneal injection of CCl4 (1.0 ml/kg BW) at which time apparent liver injury and hepatic TG accumulation occurred. TJ-15 significantly prevented not only the progression of liver injury but also inhibited hepatic TG accumulation with the progression of the injury in a dose-dependent manner when these effects were examined 24 h after CCl4 injection. In CCl4-untreated rats with oral administration of TJ-15 at a dose of 100, 250 or 500 mg/kg BW, liver and serum TG concentrations decreased depending on the dose of the herbal medicine. These results indicate that in rats intoxicated once with CCl4, orally administered TJ-15 can inhibit hepatic TG accumulation with the progression of acute liver injury by its decreasing action on serum and liver TG levels, leading to a prevention of the progression of the liver injury.

Changes in nitric oxide production with lesion development in the gastric mucosa of rats with water immersion restraint stress

In rats with gastric mucosal lesions induced by water immersion restraint (WIR) stress over a 6 h period, increases in the serum and gastric mucosal concentrations of nitrite/nitrate, the breakdown products of NO, occurred with a drastic increase in inducible NO synthase (iNOS) activity in the gastric mucosa. Pretreatment with aminoguanidine (100 mg/kg), a relatively selective iNOS inhibitor, attenuated not only gastric mucosal lesion development, but also increases in serum and gastric mucosal nitrite/nitrate concentrations with inhibition of increased gastric mucosal iNOS activity in rats with 6 h of WIR stress. A good positive correlation between either serum or gastric mucosal nitrite/nitrate concentration and gastric mucosal iNOS activity in all rats used (r = 0.741 or 0.842, respectively, p < 0.001) was found. These results suggest that in WIR-stressed rats, an increase in NO production via iNOS in the gastric mucosa could contribute to gastric mucosal lesion development.

Impact of coronary risk factors on contribution of nitric oxide and adenosine to metabolic coronary vasodilation in humans

OBJECTIVES

The contribution of nitric oxide (NO) and adenosine to the increase in coronary blood flow (CBF) induced by cardiac pacing was investigated in 28 subjects with angiographically normal coronary arteries with and without one or more risk factors for atherosclerosis.

BACKGROUND

NO and adenosine are important in the regulation of coronary circulation, and the inhibition of NO synthesis increases adenosine production during cardiac pacing in experimental models.

METHODS

Coronary artery diameters and CBF were assessed by quantitative coronary arteriography and Doppler flow velocity measurement. Plasma levels of nitrites and nitrates (NOx) (stable end products of NO), adenosine and lactate were measured, and blood gas analysis was performed.

RESULTS

The extent of CBF response to cardiac pacing did not differ between the 14 subjects with and the 8 subjects without risk factors for atherosclerosis. NOx (12.0+/-0.9 vs. 14.9+/-1.1 ,amol/liter [mean+/-SD], p < 0.05), but not adenosine (50.8+/-7.2 vs. 50.8+/-6.5 nmol/liter), levels in coronary sinus blood increased in the subjects without risk factors. In contrast, adenosine (58.9+/-7.5 vs. 77.4+/-9.8 nmol/liter, p < 0.05), but not NOx (11.1+/-1.1 vs. 12.2+/-1.1 micromol/liter), levels increased in subjects with risk factors. Aminophylline, an antagonist of adenosine receptors, blunted CBF response to cardiac pacing in six subjects with risk factors. The number of risk factors showed a negative correlation (p < 0.05) with NOx production and a positive correlation (p < 0.05) with adenosine production during cardiac pacing, respectively.

CONCLUSIONS

NO and adenosine are increased during metabolic coronary vasodilation induced by cardiac pacing. Adenosine production may be a compensatory mechanism when NO production is reduced.

Probucol improves endothelial-dependent relaxation and decreases vascular superoxide production in cholesterol-fed rabbits

Recent data indicate that hypercholesterolemia increases endothelial superoxide anion (.O2-) production, and that this diminishes the bioactivity of nitric oxide produced in the endothelium. Probucol, a drug commonly employed for treatment of hypercholesterolemia, has antioxidant properties and inhibits oxidation of low density lipoproteins in vitro. We tested the hypothesis that probucol would decrease vascular .O2- production and improve endothelium-dependent relaxations in cholesterol-fed rabbits. Rabbits were divided into four groups: 1) a control group fed a standard diet; 2) a probucol group fed a standard diet containing 0.3% probucol; 3) a hypercholesterolemic group fed a diet containing 0.5% cholesterol; 4) a hypercholesterolemia-probucol group fed a diet containing 0.5% cholesterol and 0.3% probucol. The cholesterol-rich diet markedly increased plasma total cholesterol level and lipid peroxidation in the plasma, as reflected by thiobarbituric acid-reactive substances (TBARS). This concentration of probucol did not lower plasma cholesterol, but markedly reduced TBARS in the plasma of cholesterol-fed rabbits. Aortic segments from cholesterol-fed rabbits produced 1.8-fold more .O2- (assessed by lucigenin-enhanced chemiluminescence) and decreased endothelium-dependent vascular relaxations to acetylcholine compared to vessels from normal rabbits. In cholesterol-fed rabbits, probucol treatment normalized both .O2- production and endothelium-dependent relaxations to acetylcholine. In control rabbits, probucol had no effect on either of these parameters. We conclude that probucol treatment may prevent .O2(-)-induced inactivation of endothelium-derived nitric oxide and reduce vascular oxidant stress via reducing the level of .O2-.

Preventive effect of gamma-glutamylcysteinylethyl ester on carbon tetrachloride-induced hepatic triglyceride accumulation in mice

The effect of gamma-glutamylcysteinylethyl ester (gamma-GCE), which is a precursor of reduced glutathione (GSH), on carbon tetrachloride (CCl4)-induced hepatic triglyceride (TG) accumulation in mice was investigated in comparison with that of GSH. Administration of gamma-GCE (160 micromol/kg), but not GSH (160 micromol/kg), to mice at 3 h after CCl4 injection (1 ml/kg, i.p.) significantly attenuated an increase in hepatic TG concentration at 6, 12, and 24 h after the CCl4 injection. A decrease in hepatic GSH concentration after the CCl4 injection was significantly diminished by the gamma-GCE administration, but not by the GSH administration. The correlation coefficient between hepatic TG concentration and hepatic GSH concentration was -0.627 (P < 0.001) when the results of all mice were grouped together. These results indicate that gamma-GCE can attenuate CCl4-induced hepatic TG accumulation in mice through the maintenance of hepatic GSH level.

Contribution of NO synthases to neutrophil infiltration in the gastric mucosal lesions in rats with water immersion restraint stress

A decrease in constitutive NO synthase (cNOS) activity and an increase in inducible NO synthase (iNOS) activity occurred with an increase in myeloperoxidase (MPO) activity, an index of neutrophil infiltration, in the gastric mucosa of rats with water immersion restraint (WIR) stress. This increase in gastric mucosal MPO activity was enhanced by pretreatment with NG-monomethyl L-arginine, a non-selective NOS inhibitor, but was prevented with maintenance of gastric mucosal cNOS activity by pretreatment with aminoguanidine, a selective iNOS inhibitor. The MPO activity was negatively correlated with the cNOS activity in all WIR-stressed rats used (r=-0.723). These results suggest that a decrease in cNOS activity could contribute to an increase in neutrophil infiltration in the gastric mucosa of WIR-stressed rats.

Group I introns found in Chlorella viruses: biological implications

More than 80 group I introns were detected and characterized in Chlorella viruses isolated from various locations in Japan; the overall average frequency of viruses containing the group I intron was 8.0%. Although most of these introns were inserted in the gene for either transcriptional elongation factor TFIIS (approximately 60%) or URF 14.2 (unidentified open reading frame coding for a 14.2-kDa polypeptide) (approximately 40%), in a few cases, the gene for the major capsid protein Vp52 contained an intron. These introns were biologically active (self-splicing) both in vivo and in vitro. Viruses that contained introns almost usually contained only one, but more than two introns coexisted in several virus isolates. Nucleotide sequence analysis showed that the intron sequences have diverged under strong constraint of the exon genes: introns in the same gene showed more than 99% sequence identity, whereas introns in different genes were only 72-78% identical. Phylogenetic analysis suggested relatedness of these introns to those found in the rRNA genes of a variety of organisms including green algae, red algae, red algae, yeasts, fungi, and protozoa.

Histopathology of recurrent gelatinous drop-like corneal dystrophy

PURPOSE

To elucidate more fully the histopathology of gelatinous drop-like corneal dystrophy in a case that recurred and was operated on 7 years after the original surgery.

METHODS

Transmission electron microscopy, including the use of cuprolinic blue to image sulfated proteoglycans, and horseradish peroxidase as a marker for in vitro epithelial permeability.

RESULTS

Our patient's epithelium was often abnormally thick, and many intercellular spaces were present at all levels, although cell-cell contact via desmosomes was also evident. Horseradish peroxidase, when used as an in vitro tracer, was able to penetrate the most superficial tight junctions of the corneal epithelium. Basal epithelial cells were not columnar, and numerous spike-like projections protruded into the underlying amyloid/collagenous tissue from the basal epithelium. Beneath this, duplication of a discontinuous epithelial basement membrane was noted. In this region, collagen often coexisted with amyloid, the deposition of which was extensive. As in some other corneal pathologies, long-spacing collagen was detected. The association of small proteoglycans with collagen was unremarkable, although some abnormally large, sulfated proteoglycan filaments were interspersed with the amyloid and underlying stroma.

CONCLUSION

Recurrent gelatinous drop-like corneal dystrophy shares several histopathologic features with its primary counterpart, although some features, such as the presence of abnormally large, sulfated proteoglycans and long-spacing collagen, the permeability of the epithelial tight junctions, and the duplication of the epithelial basement membrane, have not been reported previously.

Gamma-glutamylcysteinylethyl ester attenuates progression of carbon tetrachloride-induced acute liver injury in mice

We examined the effect of gamma-glutamylcysteinylethyl ester (gamma-GCE), which is readily transported into hepatocytes and increases hepatocellular reduced glutathione (GSH) levels, on the progression of carbon tetrachloride (CCl4)-induced liver injury in mice in comparison with that of GSH. Administration of more than 160 micromol/kg of gamma-GCE, but not GSH, to mice at 3 h after intraperitoneal injection of CCl4 (1 ml/kg) significantly attenuated increases in serum aspartate aminotransferase and alanine aminotransferase activities at 24 h after the CCl4 injection. Increases in hepatic lipid peroxide (LPO) concentrations and decreases in hepatic GSH concentrations after the CCl4 injection were significantly diminished by the gamma-GCE (160 micromol/kg) administration, but not by the same dose of GSH. Gamma-GCE, gamma-glutamylcysteine, and cysteine acted as substrates for glutathione peroxidases much less efficiently than GSH in the post-mitochondrial fraction of normal mouse liver cells. These results indicate that gamma-GCE attenuates the progression of CCl4-induced acute liver injury in mice through the maintenance of hepatic GSH levels, leading to inhibition of hepatic LPO formation, which could be due to an efficient utilization of GSH converted from gamma-GCE in the liver cells.

Mast cells in osteoarthritic and rheumatoid arthritic synovial tissues of the human knee

The distribution and density of mast cells in the normal and diseased synovial membranes were investigated. The mast cell count (MCC) in the osteoarthritic (OA) synovium (36.9 +/- 26.9 cells/mm2) was significantly higher than that in the rheumatoid arthritic (RA) synovium (18 +/- 12.3 cells/mm2). There was a marked positive correlation between the MCC and the volume of joint fluid in OA (r = 0.544). There was a marked negative correlation between the MCC and the volume of joint fluid in RA (r = -0.478). The synovial inflammatory score had a poor correlation with the MCC in OA (r = 0.377) and RA (r = 0.305). No correlation was noted between MCC and age, sex, roentgenographic grades, disease duration, C-reactive protein or leucocyte number in synovial fluid. Our data suggests, thus, that mast cells could be involved in the pathogenesis of inflammatory diseases of the synovium, especially in the mechanism of hydroarthrosis.

Fibrous structure and connection surrounding the metacarpophalangeal joint

The fibrous components of the metacarpophalangeal (MP) joint including the palmar plate, the collateral ligament and the dorsal plate were studied with particular attention paid to the fibrous structure of the fibrous tendon sheath and the deep transverse metacarpal ligament. The tough fibrillar structure around the MP joint, especially the force nucleus, consisted of three types of mixed fibers: the fibrous tendon sheath of the A1 pulley, the deep transverse metacarpal ligament, and the palmar plate. The tendon sheath was located on the ulnar side in the index and middle fingers, on the central position in the ring finger, and on the radial side in the little finger. These fibrous connections among the fingers formed a transverse arch in the hand. The palmar plate of the MP joint was relatively rigid and appears to function as a cushion when flexed. A fold-like protrusion of the synovial layer of the palmar plate of the MP joint had a meniscoid function, which was larger than that of the proximal interphalangeal joint. The capsule of the MP joint was thicker at the dorsal area, forming a dorsal plate, which is a sliding floor of the extensor mechanism and has a meniscoid function for joint congruity. The main lateral stabilizer consisted of collateral ligaments and accessory collateral ligaments anchored to the palmar plate. These structures act together as a "phalangeal cuff", connecting the proximal phalanx to the metacarpal head and stabilizing the MP joint.

Expression of interleukin-12 in synovial tissue from patients with rheumatoid arthritis

OBJECTIVE

To examine the importance of interleukin-12 (IL-12) as a factor in the interferon-gamma (IFNgamma)-dominant T cell cytokine response in the synovial tissue of patients with rheumatoid arthritis (RA).

METHODS

The expression of IL-12 in synovial tissue samples from patients with chronic RA (> or = 2 years) was compared with that in samples from osteoarthritis (OA) patients by detection of IL-12 p40 messenger RNA (mRNA) using reverse transcriptase-polymerase chain reaction, measurement of IL-12 p70 protein in culture supernatants of tissue cells by immunoassay, and immunostaining of tissue sections with anti-IL-12 p70. The production of IFNgamma by RA synovial tissue cells cultured with or without IL-12 was determined. In addition, T cells were obtained 14 days after culturing RA synovial tissue cells with IL-2 alone or with IL-2 plus IL-12, neutralizing anti-IL-12, or IL-4, and cytokine patterns (i.e., IFNgamma and IL-4 levels) were determined by stimulating cells for 24 hours with anti-CD3 plus phorbol myristate acetate.

RESULTS

Synovial tissues from RA patients more strongly expressed IL-12 p40 mRNA than did OA tissues. Dissociated tissue cells from 21 of 37 RA patients spontaneously released detectable amounts of IL-12 p70 (> or = 12.5 pg/ml) in culture, whereas production of IL-12 by OA tissues was limited. By immunohistochemical analysis, IL-12-producing cells were localized mainly in the sublining layer of RA synovium, and mostly expressed the CD68 antigen. Levels of IFNgamma production by RA synovial tissue cells were potently and selectively enhanced by IL-12. The ability of IL-2-expanding synovial T cells to produce IFNgamma was augmented by costimulation with IL-12 and diminished by anti-IL-12, while it was not affected by IL-4.

CONCLUSION

These data suggest that IL-12, produced mainly by macrophage-lineage cells, may be involved in IFNgamma-dominant cytokine production by infiltrating T cells in joints with chronic RA.

Closed-loop subcutaneous insulin infusion algorithm with a short-acting insulin analog for long-term clinical application of a wearable artificial endocrine pancreas

Considering the management and safety of the insulin delivery route when a wearable artificial endocrine pancreas is applied to ambulatory diabetic patients on a long-term basis, we developed a s.c. insulin infusion algorithm by analyzing the dynamics of a s.c. injected short-acting insulin analog (Insulin Lispro) by a three-compartment model. Principally the insulin infusion algorithm was developed as a transfer function with the first-order delay in both proportional and derivative actions to blood glucose concentrations. The parameters for this algorithm were calculated to simulate a physiological plasma insulin profile as closely as possible. By applying this algorithm with regular insulin, diabetic patients showed a 2 h postprandial hyperglycemia and a delayed hyperinsulinemia, followed by hypoglycemic episodes 4-5 h after oral glucose load, just as observed in the computer simulation study. However, using Insulin Lispro, a near-physiological glycemic control (postprandial blood glucose of 153.1 +/- 8.3 mg/100 ml at 60 min and 90.3 +/- 7.1 mg/100 ml at 180 min, respectively) could be achieved without showing any delayed hyperinsulinemia or hypoglycemia. Daily glycemic excursions were also controlled near-physiologically and although the daily insulin requirement (731.7 +/- 160.5 mU/kg/day) was slightly higher, it was not significantly different from that with i.v. insulin infusion (622.3 +/- 142.6 mU/kg/day). These results indicate that the application of s.c. insulin infusion algorithm with Insulin Lispro is feasible for long-term glycemic control with a wearable artificial endocrine pancreas in ambulatory diabetic patients.

Analysis of urinary albumin, transferrin, N-acetyl-beta-D-glucosaminidase and beta2-microglobulin in patients with impaired glucose tolerance

We investigated the changes in urinary albumin and urinary transferrin as glomerular proteins, and in urinary N-acetyl-beta-D-glucosaminidase and urinary beta2-microglobulin as tubular proteins, in patients with impaired glucose tolerance. We attempted to compare the proteins of normal subjects to those of diabetics with pre-nephropathy. Transferrin and N-acetyl-beta-D-glucosaminidase levels were significantly increased in patients with impaired glucose tolerance, while albumin and beta2-microglobulin levels were only slightly increased. In addition, there was no significant difference in transferrin levels between patients with impaired glucose tolerance and type 2 diabetics with pre-nephropathy. In our observation, although albumin levels were only slightly increased in patients with impaired glucose tolerance, a sharp increase in transferrin levels was reflected in patients with glomerular disorders. In addition, since N-acetyl-beta-D-glucosaminidase levels varied markedly, tubular disorders were suspected. It should be stressed that increased parameters for both glomerular and tubular disorders in group C--patients who showed abnormal levels in three proteins--had already been observed in some patients with impaired glucose tolerance. Therefore, the evaluation of the mutual relationships between various urinary protein components in patients with impaired glucose tolerance will become a more important assessment tool than that of single urinary protein components.

A case of infectious crystalline keratopathy occurring long after penetrating keratoplasty

PURPOSE

To report a 64-year-old woman's case of infectious crystalline keratopathy (ICK) that occurred 9 years after the penetrating keratoplasty (PKP).

METHODS

This study includes clinical history and histopathologic findings of the case.

RESULTS

As historic background, the patient underwent PKP for lattice dystrophy and later, persistent epithelial defect occurred on the graft. Topical steroid treatment and a therapeutic soft contact lens were applied; however, ICK developed and second PKP was performed. In the ICK region, yeasts were cultured and histologically, degenerated keratocytes containing yeast particles surrounded the intralamellar plaques of yeasts without accompanying inflammatory cells.

CONCLUSION

This case is possibly the first to develop ICK long after PKP. Histologically, ICK presumably occurred based on the immunologically incompetent condition, and, by verifying the previous reports, the neurotrophic background after PKP may partially be involved in the development of ICK.

Pharmacokinetic models to evaluate radiolabeling reagents for protein radiopharmaceuticals

Pharmacokinetic models were constructed to further estimate the hepatic radioactivity levels derived from bifunctional chelating agents used for radiolabeling of proteins. Both galactosyl-neoglycoalbumin (NGA) and mannosyl-neoglycoalbumin (NMA) were labeled with (111)In using two benzyl-EDTA derivatives. Time-activity profiles for the liver with gallbladder, intestine, and blood after administration of (111)In-labeled NGAs in mice were simultaneously fitted to a multi-compartment model, and the first-order rate constants representing the disappearance from parenchymal cells were obtained. Similarly, a model composed of the blood and liver compartment was constructed, and the disappearance rate constants from nonparenchymal cells were calculated from the biodistribution studies following administrations of (111)In-labeled NMAs. Fitting curves showed good agreements with the experimental data. Each rate constant clearly distinguished the elimination rate of the respective radiometabolite from the liver cells. Thus, quantitative estimations of radiolabeling reagents were performed only by animal biodistribution studies, and the present pharmacokinetic analyses would be useful for screening of newly designed reagents for protein radiopharmaceuticals.

Enhanced, simplified glucose sensors: long-term clinical application of wearable artificial endocrine pancreas

At present, 2 major problems should be solved before long-term application of the wearable artificial endocrine pancreas, the development of a reliable and stable glucose monitoring system and the development of a subcutaneous insulin infusion algorithm. With either a miniaturized extracorporeal glucose monitoring system based on microdialysis sampling method or a ferrocene-mediated needle-type glucose sensor covered with highly biocompatible membrane, poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (poly[MPC-co-BMA]) membrane, subcutaneous glucose concentrations could be monitored for 7 days without any in vivo calibrations, followed by 14 days with one point calibration. Considering the management and safety of the insulin delivery route, subcutaneous insulin infusion is obligatory. With the subcutaneous insulin infusion algorithm using a short acting insulin analogue (Insulin Lispro), near physiological glycemic control could be established in diabetic patients without showing any delayed hyperinsulinemia or hypoglycemia. The wearable artificial endocrine pancreas is now recognized as an excellent therapeutic tool for regulating blood glucose excursions physiologically in ambulatory diabetic patients on a long-term basis.