Birt‐Hogg‐Dubé syndrome‐associated renal cell carcinoma: Histopathological features and diagnostic conundrum

Birt‐Hogg‐Dubé (BHD) syndrome is associated with the development of hereditary renal cell carcinoma (RCC) and is caused by a germline mutation in the folliculin gene. Most cases of BHD syndrome‐associated RCC (BHD‐RCC) are less aggressive than sporadic clear cell RCC and multifocal. Therefore, it is critical to distinguish BHD‐RCC from its sporadic counterparts to identify and monitor affected families and to preserve renal function for as long as possible. The World Health Organization/International Society of Urological Pathology consensus classification defined distinct entities for certain hereditary RCC; however, BHD‐RCC was not included in this classification. Although the clinical features and molecular mechanisms of BHD‐RCC have been investigated intensively over the last two decades, pathologists and urologists occasionally face difficulties in the diagnosis of BHD‐RCC that require genetic testing. Affected patients usually have miscellaneous benign disorders that often precede renal carcinogenesis. In the present review, we summarize the current understanding of the histopathological features of BHD‐RCC based on our epidemiological studies of Japanese families and a literature review. Pathological diagnostic clues and differential diagnosis of BHD‐RCC from other hereditary RCC are also briefly discussed.     

Urine screening for patients with developmental disabilities detected a patient with creatine transporter deficiency due to a novel missense mutation in SLC6A8

Creatine transporter deficiency (CTD) is an example of X-linked intellectual disability syndromes, caused by mutations in SLC6A8 on Xq28. Although this is the second most frequent genetic cause of intellectual disabilities in Europe or America after Fragile X syndrome, information on the morbidity of this disease is limited in Japan. Using the HPLC screening method we have established recently, we examined samples of urine of 105 patients (73 males and 32 females) with developmental disabilities at our medical center. And we have found a family with three ID boys with a novel missense mutation in SLC6A8. This is the second report of a Japanese family case of CTD. A systematic diagnostic system of this syndrome should be established in Japan to enable us to estimate its frequency and treatment.     

Differential hormonal profiles of adrenomedullin and proadrenomedullin N-terminal 20 peptide in patients with heart failure and effect of treatment on their plasma levels

BACKGROUND: Adrenomedullin (AM) is a potent vasodilatory peptide discovered in human pheochromocytoma tissue. Proadrenomedullin N-terminal 20 peptide (PAMP) processed from an AM precursor is also a novel hypotensive peptide which inhibits catecholamine secretion from sympathetic nerve endings. HYPOTHESIS: The present study sought to examine the relationships between the two peptides and other clinical parameters by measuring the plasma AM and PAMP concentrations in 98 patients with heart failure. METHODS: In all, 98 patients [65 men and 33 women, aged 58.2 +/- 11.0 years, mean +/- standard deviation (SD)] with heart failure and 26 healthy volunteers (12 men and 14 women, aged 54.1 +/- 8.6 years) were examined in this study. Heart failure was secondary to previous myocardial infarction in 58 patients, valvular disease in 28, cardiomyopathy in 9, and congenital heart disease in 3. All patients were classified into two groups of class I or II (Group 1) and class III or IV (Group 2) according to the New York Heart Association (NYHA) functional classification. RESULTS: Both plasma AM and PAMP concentrations in the patients were significantly higher than those in healthy volunteers. In addition, plasma AM and PAMP concentrations in patients in class III or IV of New York Heart Association (NYHA) classification were significantly higher than those in NYHA class I or II. The elevated plasma concentrations of these peptides in patients in NYHA class III or IV significantly decreased in response to the treatment for 7 days. There was a significant correlation between plasma AM and PAMP, though the plasma concentration of PAMP was one-fifth to one-seventh of that of AM in patients and controls. The plasma AM concentration correlated significantly with the plasma concentrations of atrial and brain natriuretic peptides, epinephrine, and right atrial pressure, whereas such a relationship was not noted for the plasma PAMP concentration. CONCLUSIONS: Judging from the difference in not only the biological actions but also the hormonal profiles between AM and PAMP, they may differentially modulate the cardiovascular system in patients with heart failure, although they are processed from the same precursor.     

Oral administration of taurine improves experimental pancreatic fibrosis

Background and Aim: The mechanism of pancreatic fibrosis is unclear. Taurine is used in the clinical treatment of a wide variety of diseases, but its effect on improving pancreatic fibrosis is unknown. We examined whether a diet with added taurine improves pancreatic fibrosis induced by dibutyltin dichloride (DBTC) in an experimental chronic pancreatitis rat model. In addition, we examined the influence of taurine on pancreatic stellate cells. Methods: Pancreatic fibrosis was induced by DBTC. Rats were fed a taurine‐containing diet or a normal diet and were killed at 4 weeks. Pancreatic stellate cells were isolated from male Wistar rats. Cultured pancreatic stellate cells were incubated with or without taurine chloramine. Type I collagen and transforming growth factor‐β1 secretion was evaluated by ELISA, and matrix metalloproteinase activity was assessed by gelatin zymography. Interleukin‐6, interleukin‐2, and transforming growth factor‐β1 levels in the supernatants of pancreatic tissue homogenates were measured. Results: Pancreatic fibrosis induced by DBTC was improved remarkably by the oral administration of the taurine‐containing diet. Taurine chloramine decreased type I collagen, transforming growth factor‐β1, and matrix metalloproteinases 2 of the pancreatic stellate cell culture supernatant. Increased interleukin‐6 and decreased interleukin‐2 were found in the supernatants of the pancreatic tissue homogenates of DBTC‐induced pancreatitis rats compared with other groups. Conclusion: The oral administration of taurine improves pancreatic fibrosis. Taurine chloramine inhibits transforming growth factor‐β1 produced from activated pancreatic stellate cells and improves pancreatic fibrosis.     

Niflumic acid inhibits goblet cell degranulation in a guinea pig asthma model

Background: Human Ca^2 +-activated Cl ion channel 1 (hCLCAl) is expressed in goblet cell hyperplasia in the airway of asthmatics, and murine CLCA3 is associated with antigen-sensitized and IL-13-induced goblet cell metaplasia in mice. However, the role of CLCA in goblet cell degranulation is not fully investigated. Niflumic acid (NFA), a relatively specific CLCA inhibitor, inhibits goblet cell metaplasia, but the effect of NFA on goblet cell degranulation has not been determined in an asthma model.Methods: Guinea pigs were sensitized with ovalbumin (OA) twice and then challenged with saline, OA, histamine, and one of the Ca^2 + -dependent secretagogues, UTP. The PAS/AB-stained mucus area in the tracheal epithelium was measured with a computer image analysis system, and the morphology of mucus granules was examined by transmission electron microscopy. In the in vitro experiment, goblet cells cultured with IL-13 at the air-liquid interface were stimulated with UTP in the presence or absence of NFA, and the MUC5AC level in cell lysates was measured by ELISA.Results: The mucus areas were smaller in the OA-, histamine-, and UTP-challenged animals than in the saline-challenged animals. NFA inhibited the decrease in mucus area and morphological changes in mucus granules. UTP caused swelling and exocytosis of mucus granules and MUC5AC secretion by cultured goblet cells, and NFA inhibited these changes.Conclusions: NFA inhibited the secretory response of mucus granules in an asthma model, suggesting that CLCA may be associated with goblet cell degranulation and that CLCA inhibitors may be useful for the treatment of hypersecretion in asthma.     

Sensory neurite outgrowth on white matter astrocytes is influenced by intracellular and extracellular S100A4 protein

The central nervous system (CNS) is considered a nonpermissive environment for axonal regeneration because of the presence of myelin and associated repulsive molecules. However, neural cells transplanted to the CNS preferably migrate and extend their fibers in white matter areas. We previously showed that white matter astrocytes in vivo express the calcium-binding protein S100A4, which is strongly up-regulated in areas of white matter degeneration. To investigate the role of white matter astrocytes and their specific protein S100A4 in axonal regeneration, we developed white matter astrocyte cultures with strong S100A4 expression and grew dissociated adult dorsal root ganglion (DRG) cells on top of astrocytes for 24 hr. By using small interfering S100A4 RNA, we were able to eliminate S100A4 expression and compare growth of DRG cell neurites on S100A4-silenced and S100A4-expressing astrocytes. In addition, we studied whether extracellular S100A4 has an effect on neurite growth from adult DRG cells cultured on S100A4-expressing white matter astrocytes. Our data show that white matter astrocytes are permissive for neurite growth, although high levels of S100A4 in white matter astrocytes have a negative effect on this growth. Extracellular application of S100A4 induced extensive growth of DRG cell neurites on white matter astrocytes. These findings suggest that white matter astrocytes are able to support axonal regeneration and, furthermore, that administration of extracellular S100A4 provides strong additional support for axonal regeneration.     

Transcorneal electrical stimulation of retina to treat longstanding retinal artery occlusion

Purpose To report the outcome of transcorneal electrical stimulation (TES) of the visual system on long-standing retinal artery occlusion (RAO). Design Open labeled, case series. Patients and methods Two patients with central RAO (15 and 33 months respectively) and one with branch RAO (26 months) underwent TES therapy. Subjective and objective ophthalmological evaluations were performed before and after the TES. The ages of the patients were 38, 49, and 63 years. The TES (20 Hz biphasic pulses, 30 minutes, up to 1100 uA) was delivered by a bipolar contact lens electrode once a month for 3 months. Perimetric and/or electrophysiological examinations were performed as outcome measures. Results The visual acuity improved by more than 0.2 logMAR units in two cases, and the visual fields were improved in all three cases. The multifocal ERGs which had been reduced in the loci corresponding to the ischemic retinal area were improved after the treatment in two cases. Neither ocular nor systemic adverse effects were observed except for transient superficial keratitis. Conclusions TES of the retina can improve retinal function in eyes with long-standing RAOs. None of the authors have any financial or proprietary interest in any material or methods mentioned. This study was supported by Researches on Sensory and Communicative Disorders from the Ministry of Health, Labor, and Welfare, Japan.