Inhibitory effect of a proline-to-alanine substitution at codon 12 of peroxisome proliferator-activated receptor-gamma 2 on thiazolidinedione-induced adipogenesis.

Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a member of the nuclear hormone receptor superfamily of transcription factors and appears to be a key regulator of adipogenesis. Members of the thiazolidinedione class of insulin-sensitizing agents act as high-affinity ligands for PPARgamma, indicating that PPARgamma is also important in systemic insulin action. To determine whether Pro(12) --> Ala (P12A) mutation in PPARgamma gene contributes to the development of obesity or insulin sensitivity, we examined the effects of the P12A mutation on the function of PPARgamma by expression of the mutant protein in COS or 3T3-L1 cells. The abilities of the P12A mutant of PPARgamma to mediate both transcriptional activation of a luciferase reporter gene construct containing the peroxisome proliferator response element and adipogenesis induced by a thiazolidinedione drug were reduced compared with those of the wild-type protein. These results suggest that the P12A substitution in PPARgamma gene may be associated with abnormalities of adipose tissue formation and insulin sensitivity.

Inhibition of adipogenesis by a COOH-terminally truncated mutant of PPARgamma2 in 3T3-L1 cells.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear receptor that is thought to be an important regulator of adipocyte differentiation. This ligand-dependent transcription factor is also activated by thiazolidinediones, a new class of synthetic antidiabetic drugs, resulting in a marked adipogenic response in cultured cells and enhanced insulin sensitivity in vivo. The importance of the COOH-terminal region of PPARgamma2 in thiazolidinedione-induced adipogenesis has now been investigated by expression of a mutant protein (PPARgamma2-DeltaC) that lacks the COOH-terminal 16 amino acids of full-length PPARgamma2. The mutant protein failed to bind a thiazolidinedione ligand, but its ability to bind the peroxisome proliferator response element was similar to that of the wild-type protein. Expression of PPARgamma2-DeltaC inhibited the thiazolidinedione-induced increase in trans-activation activity of endogenous PPARgamma in CV-1 cells. Furthermore, the mutant protein prevented thiazolidinedione-induced adipogenesis in 3T3-L1 cells, whereas expression of recombinant wild-type PPARgamma2 promoted adipogenesis. These data show not only that the COOH-terminal region of PPARgamma2 is indispensable for thiazolidinedione-induced adipogenesis mediated by this protein in 3T3-L1 cells, but also that the PPARgamma2-DeltaC mutant acts in a dominant negative manner by interfering with the access of endogenous PPARgamma to the peroxisome proliferator response element of target genes.

[A case of MPO-ANCA positive progressive systemic sclerosis with status epileptics].

A 37-year-old female, who had been suffering from progressive systemic sclerosis (PSS) with long-term renal failure, was diagnosed as MPO-ANCA positive PSS in active stage. She had systemic scleroderma, normotensive renal failure and pulmonary fibrosis. Respiratory management and steroid therapy under the control of CVVH were done for her treatment. She developed hemolytic anemia and thrombocytopenia during the treatment. She was diagnosed as microangiopathic hemolytic anemia, and was treated with plasma exchange treatment. About eight weeks after her admission, she developed status epileptics. Cerebral computed tomography and lumbar puncture did not reveal any abnormal sign. The case reported herein is a MPO-ANCA positive PSS with normotensive renal failure. Generally, PSS rarely reveals neurological sign. This case suggests possibility of association between MPO-ANCA and systemic vasculitis in PSS.

Inhibition of the binding of SNAP-23 to syntaxin 4 by Munc18c.

SNARE proteins have been implicated in the insulin-induced translocation of vesicles containing the GLUT4 glucose transporter to the plasma membrane of adipocytes. The role of the target SNARE SNAP-25 or its homologs in this process was investigated by screening a mouse adipocyte cDNA library with rat SNAP-25 and human SNAP-23 cDNA probes. Both positive clones isolated encoded a protein with 87% sequence identity to human SNAP-23, and which was therefore designated mouse SNAP-23. Immunoblot and immunofluorescence analyses revealed that SNAP-23 is located predominantly in the plasma membrane of 3T3-L1 adipocytes incubated in the absence or presence of insulin. Of syntaxins 1 to 5, SNAP-23 bound with the highest affinity to syntaxins 1 and 4 in the yeast two-hybrid system. Expression of SNAP-23, syntaxin 4, and the syntaxin-binding protein Munc 18c in COS cells revealed that Munc18c reduced the amount of SNAP-23 bound to syntaxin 4 in a concentration-dependent manner. These results suggest that the binding of SNAP-23 to syntaxin 4 is inhibited by Munc18c in adipocytes.

Combination chemotherapy for malignant paraganglioma.

Treatment with a combination chemotherapeutic regimen consisting of cyclophosphamide, vincristine, and dacarbazine for malignant paraganglioma with hepatic metastasis is reported. A 51-year-old male presented with tumors in the retroperitoneal space and liver. The patient was diagnosed as having paraganglioma based on elevated levels of serum neuron-specific enolase, urinary catecholamine and vanillylmandelic acid, and on histological findings of the liver specimen. The patient was treated with this combination chemotherapy in repeated 21-day cycles. Temporary improvement in laboratory findings and a 20% reduction in the size of the hepatic masses were observed without severe adverse effects.

Human obese gene: molecular screening in Japanese and Asian Indian NIDDM patients associated with obesity.

The mouse obese (ob) gene has recently been isolated through the positional cloning technique and has been proved to result in the obese and NIDDM phenotype in mice when mutated (Nature 372:425-432, 1994). More recently, it has been demonstrated, by experiments with recombinant ob protein, that ob gene product can cause mice, including ob/ob mice, diet-induced obesity mice, and normal mice, to lower their food intake and body weight (Science 269:540-549, 1995). To investigate the genetic and/or environmental influences underlying the development of NIDDM associated with obesity, we isolated and partially sequenced the human obese (OB) gene. The human OB gene isolated in this study encoded 167 amino acids and its open reading frame was revealed to be divided into two parts with an intermediate intron of approximately 2.4 kb. Using the single-strand conformation polymorphism (SSCP) technique, we screened Japanese and Asian Indian subjects for mutations in the protein coding regions of the OB gene. A total of 75 NIDDM patients with obesity (54 Japanese and 21 Asian Indians), 40 NIDDM patients without obesity (34 Japanese and 6 Asian Indians), and 34 Japanese patients with simple obesity showed no abnormal SSCP patterns in either component of the coding sequences. These results suggested that mutations in the coding regions of the OB gene are not likely to be commonly identifiable and that there would likely be a kind of obesity-associated NIDDM not caused by mutations of the OB gene.

Pigmentary retinopathy with nephrotic syndrome, Ménétrier's disease, and diabetes mellitus.

A patient with pigmentary retinopathy, nephrotic syndrome, Ménétrier's disease, and diabetes mellitus is presented. Other complications were congestive heart failure, hypothyroidism, hypertension, and hypertriglyceridemia. Hypogenitalism was also suspected. Pigmentary retinopathy is known to associate with many systemic diseases, which are classified into several syndromes. This case superficially resembles Alström's disease due to the common characteristics of pigmentary retinopathy, diabetes mellitus, renal disease, and hypogenitalism. But clinically and histologically, there are distinct differences. To our knowledge, this association has never been reported.

A case of Behçet's disease with multiple longitudinal ulcers all over the colon.

We experienced a rare case of intestinal Behçet's disease simulating Crohn's colitis. A 70-yr-old female presented oral and genital ulcers, erythema nodosum, arthralgias, and abdominal pain. Regardless of our efforts, she died of septic shock. Autopsy showed punched-out ulcers in the terminal ileum and multiple longitudinal ulcers with inflammatory polyposis spreading from the ascending to the descending colon. The differential diagnosis of intestinal Behçet's disease versus Crohn's disease was difficult. However, microscopic findings showed nonspecific ulceration, and no evidence of Crohn's disease could be found. Clinically, the patient met the criteria of Behçet's disease, and punched-out ulcers in the ileocecal region, which is characteristic of intestinal Behçet's disease, confirmed the diagnosis of Behçet's colitis. Although rarely encountered, multiple longitudinal ulcers can involve all of the colon in Behçet's disease, like Crohn's disease.

Combination of ascorbic acid and methylprednisolone pulse therapy in the treatment of idiopathic thrombocytopenic purpura.

Ascorbic acid, reported in 1988 to be effective for idiopathic thrombocytopenic purpura (ITP), is an attractive drug because of its lack of toxicity. Further studies are necessary in order to improve its effectiveness without increasing secondary effects. We present a chronic ITP patient treated with a combination of ascorbic acid and methylprednisolone pulse (MP) therapy who was previously treated with MP therapy alone. The effect of this combination therapy seems to be better than MP therapy alone. This therapy is worth further examination as another therapeutic choice due to its fewer secondary effects than the usual regimen of corticosteroids, splenectomy, and other immunosuppressive drugs.