Mutations of carnitine palmitoyltransferase II (CPT II) in Japanese patients with CPT II deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency is an inherited disorder involving beta-oxidation of long-chain fatty acids. CPT II deficiency is a wide-spectrum disorder that includes a lethal neonatal form, an infantile form, and an adult-onset form. However, the ethnic characteristics and the relationship between genotype and clinical manifestation are not well understood. We investigated three non-consanguineous Japanese patients with CPT II deficiency and examined cell lines from 4 unrelated patients and 50 healthy donors. The CPT 2 gene was typed by direct DNA sequencing of polymerase chain reaction-amplified gene products. Case 1 (infantile form) was heterozygous for a phenylalanine to tyrosine substitution at position 383 (p.F383Y) and a novel valine to leucine substitution at 605 (p.V605L). Cases 2, 4, and 5 (infantile form) and case 3 (adult-onset form) were heterozygous for a single mutation at F383Y. Case 6 (adult-onset form) was compound heterozygous at the CPT 2 locus, with deletion of cytosine and thymine at residue 408, resulting in a stop signal at 420 (p.Y408fsX420), and an arginine to cysteine substitution at position 631 (p.R631C). Case 7 (adult-onset form) was homozygous for the p.F383Y mutation. In conclusion, we identified p.F383Y mutations in six of seven patients with CPT II deficiency and two novel variants of the coding gene: p.Y408fsX420 and p.V605L. These mutations differ from those in Caucasian patients, who commonly harbor p.S113L, p.P50H, and p.Q413fsX449 mutations; therefore, our data and those of other Japanese groups suggest that the p.F383Y mutation is significant in Japanese patients with CPT II deficiency.

Dystonia, mental deterioration, and dyschromatosis symmetrica hereditaria in a family with ADAR1 mutation

A family with dystonia associated with dyschromatosis symmetrica hereditaria (DSH), mental deterioration, and tissue calcification is described. The proband possessed an adenosine deaminase acting on the RNA 1 gene (ADAR1) mutation Gly1007Arg. This ADAR1 mutation could disturb RNA editing at Q/R sites of glutamate receptor in the brain and increase Ca(2+) influx into neurons, which is thought to induce dystonia and mental deterioration. The observations in our family raise the possibility that the ADAR1 mutation might be a direct cause or a predisposing factor for heredodegenerative dystonia. Further investigation of ADAR1 mutations will shed light on the genotype-phenotype correlation in DSH.

Biopsy-proven tuberculous meningitis mimicking CNS sarcoidosis

We report a 31-year-old man with tuberculous meningitis (TM) mimicking CNS sarcoidosis. Although Mycobacterium tuberculosis (MTB) was not detected in CSF, the level of adenosine deaminase (ADA) in CSF was significantly raised. Brain biopsy showed caseous granuloma and a diagnosis of TM was made. The diagnosis of TM is often difficult and brain biopsy should be considered if MTB is not detected in the CSF. Evaluation of CSF ADA level could also strongly contribute to distinguishing TM from other meningitis. In addition to antituberculosis drugs, corticosteroid therapy was effective in our patient but careful reduction of its dosage was required.

Diflunisal stabilizes familial amyloid polyneuropathy-associated transthyretin variant tetramers in serum against dissociation required for amyloidogenesis

Transthyretin (TTR) tetramer dissociation, misfolding and misassembly are required for the process of amyloid fibril formation associated with familial amyloid polyneuropathy (FAP). Preferential stabilization of the native TTR tetramer over the dissociative transition state by small molecule binding raises the kinetic barrier of tetramer dissociation, preventing amyloidogenesis. Two NSAIDs, diflunisal and flufenamic acid, and trivalent chromium have this ability. Here, we investigated the feasibility of using these molecules for the treatment of FAP utilizing serum samples from 37 FAP patients with 10 different mutations. We demonstrated that the TTR heterotetramer structures in FAP patients serum are significantly less stable than that in normal subjects, indicating the instability of the variant TTR structure is a fundamental cause of TTR amyloidosis. We also demonstrated that therapeutic serum concentrations of diflunisal (100-200 microM) stabilized serum variant TTR tetramer better than those of flufenamic acid (35-70 microM). Trivalent chromium at levels obtained by oral supplementation did not stabilize TTR in a statistically significant fashion. Importantly, diflunisal increased serum TTR stability in FAP patients beyond the level of normal controls.

Ghrelin prevents development of diabetes at adult age in streptozotocin-treated newborn rats

AIMS/HYPOTHESIS

Ghrelin, a stomach-derived hormone, functions in multiple biological processes, including glucose metabolism and cellular differentiation and proliferation. In this study, we examined whether early treatment with ghrelin can regenerate beta cells of the pancreas in an animal model of diabetes mellitus, the n0-STZ model, in which neonatal rats are injected with streptozotocin (STZ) at birth.

METHODS

Following administration of ghrelin to n0-STZ rats from postnatal days 2 to 8, we examined beta cell mass, mRNA expression levels of insulin and of pancreatic and duodenal homeobox 1 (Pdx1) gene, and pancreatic morphology on days 21 and 70. In addition, we investigated the effects of ghrelin on beta cell replication.

RESULTS

By day 21, ghrelin treatment increased pancreatic expression of insulin and Pdx1 mRNA in n0-STZ rats. The number of replicating cells was also significantly increased in the ghrelin-treated n0-STZ model. At day 70, n0-STZ rats exhibited hyperglycaemia, despite slight increases in plasma insulin levels. Ghrelin treatment resulted in the improvement of plasma glucose levels, which were associated with normal plasma insulin levels. Pancreatic insulin mRNA and protein levels were significantly increased in ghrelin-treated n0-STZ model animals.

CONCLUSIONS/INTERPRETATION

These findings suggest that ghrelin promotes regeneration of beta cells in STZ-treated newborn rats. Thus, early administration of ghrelin may help prevent the development of diabetes in disease-prone subjects after beta cell destruction.

Unexpectedly high incidence of visceral AA-amyloidosis in slaughtered cattle in Japan

Experimental mouse AA amyloidosis can be transmissible by dietary ingestion of amyloid fibrils and it is well known that AA amyloidosis occasionally develops in aged cattle. Bovine liver and intestine have conventionally been used in Oriental foods, and the incidence of visceral AA amyloidosis in slaughtered cattle was evaluated. Renal tissues from 302 aged cattle older than 4 years were obtained from a local abattoir. Amyloid deposition was microscopically examined and amyloid protein was immunochemically determined. Renal amyloid deposition was seen in 15 out of 302 cattle with no previous history of diseas, an incidence of 5.0%. Amyloid protein in these cattle was AA and they had pathological findings in their visceral organs on gross examination. The incidence of visceral AA amyloidosis in slaughtered cattle in this study was disturbingly high compared with those (0.4-2.7%) previously reported from Japan and other foreign countries. AA amyloidosis is a life-threatening complication in patients with chronic inflammatory diseases and these patients at risk should avoid ingesting food that may possibly contain AA amyloid fibrils. More detailed information on cattle amyloidosis is required to guarantee the safety of our food.

Skin Metabolism in Transdermal Therapeutic Systems

Skin has at least two barriers with protective functions: the stratum corneum physical barrier and a biochemical barrier in the epidermis and dermis. Numerous chemical and physical enhancers exist for transdermal therapeutic systems; some cause irritation, and possibly influence enzyme deactivation. Knowledge of enzymatic skin reactions is important for developing safe and efficacious transdermal systems for treatment not only of skin diseases but also for systemic application. This paper overviews the effects of (a) chemical enhancers and additives, (b) drug structure, and (c) physical enhancement on skin metabolism.

Multiple brain tumors of diffuse large B cell lymphoma in a patient with Waldenström's macroglobulinemia/ lymphoplasmacytic lymphoma: PCR and DNA sequence analysis show evidence of differences in clonality of the two B cell malignancies

Multiple brain tumors of diffuse large B cell lymphoma (DLBL) were observed in a 75-year-old man with Waldenström's macroglobulinemia (WM). Paravertebral and multiple subcutaneous nodules occurred in succession and he died 4 months after onset. We investigated B cell monoclonality by means of polymerase chain reaction (PCR) analysis and sequencing of the immunoglobulin heavy chain of paraffin-embedded sections. The PCR product of the brain tumors showed a different rearrangement pattern from those of the other sections. The co-occurrence of DLBL with WM is rare, and some investigators have examined the clonality of the two malignancies. This case is important because DLBL brain tumors co-occurred with WM, enabling us to prove that DLBL and WM have different clonality.

Pharmacokinetic model for in vivo/in vitro correlation of intravitreal drug delivery

A pharmacokinetic model of intravitreal drug delivery has been developed for describing the elimination and distribution of ocular drugs in the posterior segments of the eye. The model, based on Fick's second law of diffusion, assumes the cylindrical vitreous body with three major pathways for elimination: the posterior aqueous chamber, the retina/choroids/sclera (RCS) membrane and the lens posterior capsule. The model parameters such as the diffusion coefficient and the partition coefficient of the drug in the vitreous body and its surrounding tissues, the posterior lens capsule and the retina/choroids/sclera membrane, can be determined from in vitro membrane penetration experiments using respective rabbit tissues. The time course of in vivo mean concentration of the drug in the rabbit vitreous body following intravitreal drug delivery well agreed with the profile calculated from the present pharmacokinetic model for both membrane-controlled polymeric devices and biodegradable rod-matrix systems. The pharmacokinetic model suggests that the major route of elimination of drug molecules released from the vitreous implant is through the posterior aqueous humor because of the absence of a barrier membrane. However, the elimination through the RCS membrane cannot be overlooked because of the large diffusion area of the RCS membrane. The vitreous body concentration of the drug released from biodegradable vitreous implants can be predicted from the in vivo release rate-time profile by the present pharmacokinetic model.

Association of Graves' disease with Evans' syndrome in a patient with IgA nephropathy

A 20-year-old woman with IgA nephropathy was admitted to Jikei University Hospital for the treatment of rapid deterioration of renal function after receiving 131I-therapy against hyperthyroidism on October 23,1999, and hemodialysis was started. On admission, she was diagnosed as having Evans' syndrome in addition to known Graves' disease. Renal biopsy revealed end-stage renal damage, then, hemodialysis was maintained. Treatment for Evans' syndrome was also started and her general condition gradually improved. The present case implied that "Graves' disease" and "Evans' syndrome" could represent some of the manifestations of an underlying immunological disorder in the patient.

Coordinate regulation of endothelin and adrenomedullin secretion by oxidative stress in endothelial cells

To elucidate the significance of oxidative stress in the modulation of endothelial functions, we examined the effects of H(2)O(2) on the expression of two endothelium-derived vasoactive peptides, endothelin (ET) and adrenomedullin (Am), and their interaction. H(2)O(2) dose dependently suppressed ET secretion and ET-1 mRNA expression in bovine carotid endothelial cells (ECs). Menadion sodium bisulfate, a redox cycling drug, also decreased ET secretion in a dose-dependent manner. Catalase, a H(2)O(2) reductase, and dl-alpha-tocopherol (vitamin E) significantly inhibited H(2)O(2)-induced suppression of ET secretion. Downregulation of ET-1 mRNA under oxidative stress was regulated at the transcriptional level. In contrast, H(2)O(2) increased Am secretion (and its mRNA expression) accompanied by the augmentation of cAMP production. Am, as well as 8-bromo-cAMP and forskolin decreased ET secretion in a dose-dependent fashion. Furthermore, an anti-Am monoclonal antibody that we developed abolished H(2)O(2)-induced suppression of ET secretion at 6-24 h after the addition of H(2)O(2). H(2)O(2) increased the intracellular Ca(2+) concentration ([Ca(2+)](i)). Moreover, treatment with ionomycin, a Ca(2+) ionophore, and thapsigargin, an inhibitor of endoplasmic reticulum ATPase, decreased ET secretion dose dependently for 3 h. These results suggest that the production of ET was decreased via activation of the Am-cAMP pathway and by the elevation of [Ca(2+)](i) under oxidative stress. These findings elucidate the coordinate expression of two local vascular hormones, ET and Am, under oxidative stress, which may protect against vascular diseases.

An experimental approach to study the binding properties of vitamin E (alpha-tocopherol) during hairless mouse skin permeation

An experimental approach to study the binding properties of vitamin E has been developed. Total vitamin E solubility in the skin was determined by a partition study, followed by in vitro skin permeation studies with whole skin and stripped skin. The amount of freely diffusable vitamin E in the diffusion process was determined from the permeation profiles of whole skin and stripped skin by employing a bi-layer model. The concentrations of vitamin E in the stratum corneum and viable dermis were determined separately. By subtracting this amount from the total concentration of vitamin E in the skin, as determined by the solubility study, the amount of bound vitamin E was determined. After skin permeation reached a steady state, the donor solution was removed and the permeation study continued (desorption study). During the entire period of the desorption experiment, the amount of vitamin E in the receptor solution hardly increased and remained constant. After the desorption experiment, vitamin E still remaining in the skin was determined by extracting with tissue solubilizer, SOLABLE, and is considered as the amount of vitamin E strongly bound in the skin. The concentrations of bound vitamin E determined by permeation and desorption studies coincided relatively well. To further investigate skin binding of vitamin E, a differential scanning calorimetry study was performed. Vitamin E-treated stratum corneum showed phase transitions at 76 and 85 degrees C, associated with lipid transitions. The thermal transitions associated with the lipid transition suggested interactions of vitamin E with lipid components of the skin. During skin permeation, vitamin E forms a very strong reservoir in the skin tissue and this amount of vitamin E, about 30%, exists as a bound-form with the lipid components of the stratum corneum.

Positional dissociation between the genetic mutation responsible for pseudohypoparathyroidism type Ib and the associated methylation defect at exon A/B: evidence for a long-range regulatory element within the imprinted GNAS1 locus

Pseudohypoparathyroidism type Ib (PHP-Ib) is a paternally imprinted disorder which maps to a region on chromosome 20q13.3 that comprises GNAS1 at its telomeric boundary. Exon A/B of this gene was recently shown to display a loss of methylation in several PHP-Ib patients. In nine unrelated PHP-Ib kindreds, in whom haplotype analysis and mode of inheritance provided no evidence against linkage to this chromosomal region, we confirmed lack of exon A/B methylation for affected individuals, while unaffected carriers showed no epigenetic abnormality at this locus. However, affected individuals in one kindred (Y2) displayed additional methylation defects involving exons NESP55, AS and XL, and unaffected carriers in this family showed an abnormal methylation at exon NESP55, but not at other exons. Taken together, current evidence thus suggests that distinct mutations within or close to GNAS1 can lead to PHP-Ib and the associated epigenetic changes. To further delineate the telomeric boundary of the PHP-Ib locus, the previously reported kindred F, in which patient F-V/51 is recombinant within GNAS1, was investigated with several new markers and direct nucleotide sequence analysis. These studies revealed that F-V/51 remains recombinant at a single nucleotide polymorphism (SNP) located 1.2 kb upstream of XL. No heterozygous mutation was identified between exon XL and an SNP approximately 8 kb upstream of NESP55, where this affected individual becomes linked, suggesting that the genetic defect responsible for parathyroid hormone resistance in kindred F, and probably other PHP-Ib patients, is located >or=56 kb centromeric of the abnormally methylated exon A/B. A region upstream of the known coding exons of GNAS1 is therefore predicted to exert, presumably through imprinting of exon A/B, long-range effects on G(s)alpha expression.