Compensatory upregulation of myelin protein zero-like 2 expression in spermatogenic cells in cell adhesion molecule-1-deficient mice

The cell adhesion molecule-1 (Cadm1) is a member of the immunoglobulin superfamily. In the mouse testis, Cadm1 is expressed in the earlier spermatogenic cells up to early pachytene spermatocytes and also in elongated spermatids, but not in Sertoli cells. Cadm1-deficient mice have male infertility due to defective spermatogenesis, in which detachment of spermatids is prominent while spermatocytes appear intact. To elucidate the molecular mechanisms of the impaired spermatogenesis caused by Cadm1 deficiency, we performed DNA microarray analysis of global gene expression in the testis compared between Cadm1-deficient and wild-type mice. Out of the 25 genes upregulated in Cadm1-deficient mice, we took a special interest in myelin protein zero-like 2 (Mpzl2), another cell adhesion molecule of the immunoglobulin superfamily. The levels of Mpzl2 mRNA increased by 20-fold and those of Mpzl2 protein increased by 2-fold in the testis of Cadm1-deficient mice, as analyzed with quantitative PCR and western blotting, respectively. In situ hybridization and immunohistochemistry demonstrated that Mpzl2 mRNA and protein are localized in the earlier spermatogenic cells but not in elongated spermatids or Sertoli cells, in both wild-type and Cadm1-deficient mice. These results suggested that Mpzl2 can compensate for the deficiency of Cadm1 in the earlier spermatogenic cells.     

Involvement of AMPK and MAPK signaling during the progression of experimental autoimmune myocarditis in rats and its blockade using a novel antioxidant

There are various reports suggesting the role of angiotensin (Ang) receptor blockers, Ang converting enzyme inhibitors, calcium channel blockers, diuretics and antioxidants against the progression of experimental autoimmune myocarditis (EAM) to dilated cardiomyopathy (DCM). Most of them were reported to be effective during this adverse cardiac remodeling. Recently much attention has been paid to studying the involvement of AMP-activated protein kinase (AMPK) and mitogen activated protein kinase (MAPK) in various cardiovascular ailments. AMPK acts as a master sensor of cellular energy balance via maintenance of lipid and glucose metabolism. Evidences also suggest the relation between AMPK and oxidative stress during physiological and pathological myocardial cellular function. Since, it is of interest to identify the roles of AMPK and MAPK during the progression of EAM to DCM and also the effect of edaravone, a novel free radical scavenger, against its progression. For this, we have carried out western blotting, histopathological staining and immunohistochemical analyses to measure the myocardial expressions of AMPK signaling and oxidative stress related parameters in normal and vehicle or edaravone-treated EAM rats, respectively. We identified the myocardial levels of phospho Akt and phosphoinositide 3-kinase, which are the upstream proteins of AMPK and MAPK activation and both were up-regulated in the vehicle-treated rats, whereas candesartan treatment significantly reversed these changes. We have also measured the myocardial levels of p-AMPKα, different isoforms of protein kinase C and MAPK signaling proteins. All of these protein levels were significantly elevated in the hearts of DCM rats whereas edaravone treatment significantly reversed these changes. In viewing these results, we can suggest that along with MAPK, AMPK signaling also plays a crucial role in the progression of EAM and it can be effectively blocked by the treatment with a novel antioxidant, edaravone.     

Virulence of Mycobacterium avium complex strains isolated from immunocompetent patients

Mycobacterium avium complex (MAC) disease has been increasing worldwide not only in immunocompromised but also in immunocompetent humans. However, the relationship between mycobacterial strain virulence and disease progression in immunocompetent humans is unclear. In this study, we isolated 6 strains from patients with pulmonary MAC disease. To explore the virulence, we examined the growth in human THP-1 macrophages and pathogenicity in C57BL/6 mice. We found that one strain, designated 198, which was isolated from a patient showing the most progressive disease, persisted in THP-1 cells. In addition, strain 198 grew to a high bacterial load with strong inflammation in mouse lungs and spleens 16 weeks after infection. To our knowledge, strain 198 is the first isolated MAC strain that exhibits hypervirulence consistently for the human patient, human macrophages in vitro, and even for immunocompetent mice. Other strains showed limited survival and weak virulence both in macrophages and in mice, uncorrelated to disease progression in human patients. We demonstrated that there is a hypervirulent clinical MAC strain whose experimental virulence corresponds to the serious disease progression in the patients. The existence of such strain suggests the involvement of bacterial virulence in the pathogenesis of pulmonary MAC disease in immunocompetent status.     

N‐myc downstream‐regulated gene 2 protects blood–brain barrier integrity following cerebral ischemia

Disruption of the blood‐brain barrier (BBB) following cerebral ischemia is closely related to the infiltration of peripheral cells into the brain, progression of lesion formation, and clinical exacerbation. However, the mechanism that regulates BBB integrity, especially after permanent ischemia, remains unclear. Here, we present evidence that astrocytic N‐myc downstream‐regulated gene 2 (NDRG2), a differentiation‐ and stress‐associated molecule, may function as a modulator of BBB permeability following ischemic stroke, using a mouse model of permanent cerebral ischemia. Immunohistological analysis showed that the expression of NDRG2 increases dominantly in astrocytes following permanent middle cerebral artery occlusion (MCAO). Genetic deletion of Ndrg2 exhibited enhanced levels of infarct volume and accumulation of immune cells into the ipsilateral brain hemisphere following ischemia. Extravasation of serum proteins including fibrinogen and immunoglobulin, after MCAO, was enhanced at the ischemic core and perivascular region of the peri‐infarct area in the ipsilateral cortex of Ndrg2‐deficient mice. Furthermore, the expression of matrix metalloproteinases (MMPs) after MCAO markedly increased in Ndrg2^?/? mice. In culture, expression and secretion of MMP‐3 was increased in Ndrg2^?/? astrocytes, and this increase was reversed by adenovirus‐mediated re‐expression of NDRG2. These findings suggest that NDRG2, expressed in astrocytes, may play a critical role in the regulation of BBB permeability and immune cell infiltration through the modulation of MMP expression following cerebral ischemia.     

Histopathological studies of a case of cytomegalovirus retinochoroiditis.

A case of cytomegalovirus (CMV) retinochoroiditis initially misdiagnosed as fungal endophthalmitis is reported. An 83-year-old man who was suspected of having cholangiocarcinoma presented uveitis in both eyes. Candida endophthalmitis was suspected on the basis of ophthalmic findings and past history, which included systemic corticosteroid administration and intravenous hyperalimentation. Intravenous treatment with miconazole was not effective. At autopsy, 3 months after the initial ophthalmological examination, the right eye was enucleated and examined histologically and histochemically. Light microscopic examination showed extensive retinal necrosis and numerous cytomegalic cells, so-called owl's eye cells, with intranuclear and intracytoplasmic inclusion bodies. CMV particles were seen by electron microscopy, and CMV-infected cells were observed by immunohistochemical staining by the direct method with fluorescein-labeled antibodies. These findings indicate that in suspected cases of fungal endophthalmitis various tests should also be carried out for CMV.     

Secretion and clinical significance of atrial natriuretic peptide in patients with muscular dystrophy

The plasma concentration of atrial natriuretic peptide was measured in patients with muscular dystrophies to study its relationship with congestive heart failure. In patients with Duchenne muscular dystrophy, the plasma atrial natriuretic peptide concentration was 35.5 +/- 3.3 pg/mL (mean +/- SE), which was higher than that in age-matched normal subjects (9.8 +/- 0.6 pg/mL). It increased with progression of disability and showed significant correlations with the cardiothoracic ratio and the ratio of the preejection period to the left ventricular ejection time. In patients with other types of muscular dystrophy, the plasma atrial natriuretic peptide concentration showed no significant change. Immunohistochemical examination demonstrated many atrial natriuretic peptide-positive cells in atrial muscle of an autopsied patient, indicating preservation of the peptide until the end stage. These findings suggest that measurement of the plasma atrial natriuretic peptide concentration is useful for evaluating heart failure in patients with Duchenne muscular dystrophy.     

Late results after heart valve surgery in the elderly

Heart valve surgery was performed in 133 patients over the age of 60 between 1976 and 1981. There were 54 men and 79 women. Their ages ranged from 60 to 74 years (mean age 64.3 years). In this study, 54 valve prostheses (15 porcine and 39 mechanical) in the aortic position, 79 prostheses (69 porcine and 10 mechanical) in the mitral position and 3 prostheses (3 porcine) in the tricuspid position were implanted in 121 patients. Fifteen patients (11.3%) died in the hospital. The hospital mortality was high in the cases of MVR (14.6%), MVR + TAP (12.5%) and emergency (50%). The mean follow-up was 37.2 months (range 4 to 129 months, total 367.3 patient-years). There were 10 late deaths (8.5%). Actuarial survival for hospital survivors at 5 years was 89.2 per cent. At follow-up, 95.8% of the surviving patients were in New York Heart Association functional class I or II. Valve-related complications were thromboembolism (2.0% pt/year), periprosthetic leak (1.7% pt/year), primary tissue failure (0.5% pt/year) and thrombosed valve (0.3% pt/year). Anticoagulant-related hemorrhage necessitating hospitalization occurred in 2 patients (1.0% pt/year). The freedom from all events at 5 years was 72.8 per cent. This study suggests that heart valve surgery in the elderly can be performed with an acceptable mortality. Advanced age alone should not be a contraindication to surgical management.