Potential role of vacuolar H-adenosine triphosphatase in neointimal formation in cultured human saphenous vein

OBJECTIVE: Vacuolar H(+)-adenosine triphosphatase plays a pivotal role in pH regulation and molecular transport across the vacuolar membranes and is involved in cell proliferation and transformation. In the present study, possible involvement of vacuolar H(+)-adenosine triphosphatase in neointimal formation was investigated in an organ culture model of human saphenous vein. Methods and results: Cultured saphenous vein segments developed neointimal formation and marked thickening of the media within 14 days. Neointimal formation and medial thickening were completely inhibited by 10 nmol/L bafilomycin A(1), a selective inhibitor of vacuolar H(+)-adenosine triphosphatase, although structurally related macrolide antibiotics FK-506 and erythromycin were without an effect. The neointimal cells were positive for alpha-smooth muscle actin and vimentin but negative for desmin, indicative of myofibroblasts. The emergence of myofibroblasts was inhibited, and endothelial cells were preserved in the saphenous vein segments treated with bafilomycin A(1). Uptake of bromodeoxyuridine, a proliferation marker, by myofibroblasts was abrogated in the saphenous vein segments treated with 10 nmol/L bafilomycin A(1). Detection of apoptotic cells by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling concomitant with identification of desmin-expressing smooth muscle cells demonstrated that neointimal myofibroblasts, but not medial smooth muscle cells, that expressed desmin underwent apoptosis by treatment with bafilomycin A(1). CONCLUSIONS: These results suggest that vacuolar H(+)-adenosine triphosphatase may be involved in myofibroblast growth that contributes to neointimal formation and medial thickening in cultured human saphenous vein. Increased sensitivity of myofibroblasts, but not endothelial cells, and differentiated smooth muscle cells to bafilomycin A(1) may have potential therapeutic implications in the treatment for vein graft disease.     

Case of follicular mucinosis showing brownish yellow and red dots via dermoscopy

We herein describe a 68‐year‐old man with follicular mucinosis. A dermoscopic examination showed multiple, round, brownish yellow dots with a whitish rim in the follicular ostium and red dots in the interfollicular area. This case report is the first to suggest that follicular mucinosis shows these dermoscopic findings.     

Allergic bronchopulmonary mycosis characterized by chest pain and high‐attenuation mucus on computed tomography

A 45‐year‐old woman developed chest pain on the previous day. High‐attenuation mucus in the bronchus was found on the CT examination on admission, which led to a diagnosis of allergic bronchopulmonary mycosis. CT should be checked carefully for high‐attenuation mucus because this finding is highly specific for allergic bronchopulmonary mycosis.     

Involvement of DNase II-like acid DNase in the cataract formation of the UPL rat and the Shumiya cataract rat

The loss of organelles and DNA is important to ensure transparency of the lenses, and DNase II-like acid DNase (also called DNase IIbeta, DLAD) is related to the loss of organelles and DNA in the lenses. We investigated the relation between the degradation of DNA and DLAD mRNA expression in the lenses of two hereditary cataract rats, the UPL rat (UPLR) and the Shumiya cataract rat (SCR), during cataract development. Undigested DNA was detected in the lens cortexes of normal UPLRs and SCRs, and undigested DNA was degraded in the lens nuclei of normal UPLRs and SCRs. DLAD does not affect common cataract formation, since DLAD mRNA expression levels in the lenses of cataractous SCRs were not changed with an increase in age, and undigested DNA was degraded in the lens nuclei of cataractous SCRs. On the other hand, an accumulation of undigested DNA was found in the lens nuclei of cataractous UPLRs at 46 and 53 d of age with opaque lenses, and the decrease in DLAD mRNA expression levels occurred prior to the accumulation of undigested DNA in the lens nuclei. It is possible that UPLRs are a good model for cataract caused by a decrease of DNA degradation in the lenses.     

Adult bone marrow-derived stem cells use R-cadherin to target sites of neovascularization in the developing retina.

Adult bone marrow contains a population of hematopoietic stem cells (HSCs) that can give rise to cells capable of targeting sites of neovascularization in the peripheral or retinal vasculature. However, relatively little is known about the mechanism of targeting of these cells to sites of neovascularization. We have analyzed subpopulations of HSCs for the expression of a variety of cell surface adhesion molecules and found that R-cadherin, a calcium-dependent cell-cell adhesion molecule important for normal retinal endothelial cell guidance, was preferentially expressed by functionally targeting HSCs. Preincubation of HSCs with function-blocking anti-R-cadherin antibodies or novel R-cadherin-specific peptide antagonists effectively prevented targeting of bone marrow-derived cells to the developing retinal vasculature in vivo. Whereas control-injected HSCs targeted to all 3 normal developing retinal vascular layers, blocking R-cadherin-mediated adhesion resulted in mistargeting of the HSCs to the normally avascular outer retina. Our results suggest that vascular targeting of bone marrow-derived HSCs is dependent on mechanisms similar to those used by endogenous retinal vascular endothelial cells. Thus, R-cadherin antagonists may be useful in the treatment of neovascular diseases in which circulating HSCs contribute to abnormal angiogenesis.     

Contractile reserve of valvular heart diseases echocardiographically evaluated by epinephrine loading before and after cardiac surgery

In order to evaluate cardiac contractile reserve, echocardiographic studies were performed on 59 patients with acquired valvular heart disease and 13 patients with atrial septal defect. After epinephrine loading, the 59 patients were classified into three groups. In group I, echocardiographically-obtained left ventricular posterior wall excursion (PWE) remained below 10 mm after the administration of 2 microgram/min epinephrine. This group included patients with PWE below 10 mm after 1 microgram/min epinephrine loading but who could not endure the 2 microgram/min infusion because of significant adverse effects. In group II, PWE was less than 10 mm before the loading, but exceeded 10 mm after the administration of 1 or 2 microgram/min epinephrine loading. In group III, PWE exceeded 10 mm without stress. The conclusions derived from our data are as follows: The PWE and mean left ventricular posterior wall velocity (mPWV) obtained by echocardiography reflect the stroke volume derived from the thermodilution technique. It is possible to estimate the cardiac contractile force in patients who have a paradoxical motion of the interventricular septum, in the preoperative and even in the early postoperative periods. Patients whose PWE and mPWV are less than 10 mm and 35 mm/sec, respectively, after 2 microgram/min loading of epinephrine (group I), are likely to have severe cardiac failure after surgery. Inotropic stimulation is considered to be a very useful indicator for prediction of cardiac contractile reserve. Patients having decreased PWE, mPWV, mVcf and EF before surgery may have arrested recovery in both short- or long-term follow-up. However, surgical treatment is recommended for these patients with low cardiac function, because some improvement can be expected after surgery.     

Involvement of agouti-related protein, an endogenous antagonist of hypothalamic melanocortin receptor, in leptin action.

To understand the role of agouti-related protein (AGRP), an endogenous antagonist of hypothalamic melanocortin receptor, in leptin action, we produced a full-length recombinant AGRP and examined its effect on the satiety effect of leptin. We also studied leptin's regulation of hypothalamic AGRP mRNA expression. A single intracerebroventricular (i.c.v.) injection of AGRP significantly increased cumulative food intake and body weight in a dose-dependent manner in rats. The leptin-induced inhibition of food intake and body weight was reversed by co-injection of AGRP in a dose-dependent manner. Hypothalamic AGRP mRNA expression was upregulated in leptin-deficient ob/ob mice and leptin receptor-deficient db/db mice and downregulated in lethal yellow agouti mice (KKAy mice) with hyperleptinemia. A single i.c.v. injection of leptin reversed the increased AGRP mRNA levels in ob/ob mice but not in db/db mice. In control mice and KKAy mice, AGRP mRNA expression was upregulated during fasting, when plasma leptin concentrations were decreased. No significant increase in AGRP mRNA expression was noted during fasting in control mice and KKAy mice treated with leptin. This study provides the first direct evidence that AGRP is a negative regulator of leptin action, and leptin downregulates hypothalamic AGRP production. Because leptin is shown to increase hypothalamic alpha-melanocyte stimulating hormone (alpha-MSH) production, our data suggest that its action via the hypothalamic melanocortin system is determined by the balance between the levels of its agonist and antagonist, alpha-MSH and AGRP.     

Protein markers in cerebrospinal fluid in experimental nerve root injury. A study of slow-onset chronic compression effects or the biochemical effects of nucleus pulposus on sacral nerve roots

STUDY DESIGN: Measurement of changes in cerebrospinal fluid concentrations of nerve tissue markers, total proteins, and immunoglobulin after compression of nerve root or application of nucleus pulposus in a pig model. OBJECTIVES: To assess whether compression or application of nucleus pulposus to spinal nerve roots may cause increased levels of cerebrospinal fluid markers of nerve tissue damage and total proteins, and whether synthesis of immunoglobulins may be induced in cerebrospinal fluid. SUMMARY OF BACKGROUND DATA: Previous studies have reported that there seems to be a relationship between elevated cerebrospinal fluid total protein concentrations, nerve tissue markers, clinical findings, and compression of the nerve root evaluated by radiologic changes in patients with sciatica. METHODS: Subjects included 41 pigs, including 5 control animals. In two groups of experimental animals (n = 7; n = 5), an ameroid constrictor was slid onto the S1 nerve root. In two other groups (n = 7; n = 5), nucleus pulposus harvested from the L2-L3 disc was applied to the S1 nerve root. Two sham animal groups (n = 7; n = 5) underwent the same laminectomy. Twenty-one pigs underwent reoperation after 1 week, and 15 pigs after 4 weeks. A syringe was used to remove 3 mL of cerebrospinal fluid at L4-L5. Concentrations of total proteins, the light subunit of the neurofilament protein, S-100 protein, neuron-specific enolase, and glial fibrillary acidic protein were measured, and the presence of oligoclonal bands (immunoglobulins) were assayed in cerebrospinal fluid. RESULTS: The pigs with compressed S1 nerve root had considerably higher neurofilament protein and total protein concentrations in their cerebrospinal fluid than the-control animals (P < 0.001 and P < 0.01, respectively) or the sham animals (P < 0.001 and P < 0.05) in the 1-week experiment. Nucleus pulposus did not induce a significant increase in concentrations of the different protein markers. The presence of oligoclonal bands in cerebrospinal fluid in the experimental groups did not differ between the control and sham animals. CONCLUSIONS: The neurofilament protein and total protein concentrations in cerebrospinal fluid may have diagnostic importance in cases wherein clinical findings are not clearly related to the radiologic changes and vice versa. These protein markers also may be useful tools in different experimental models.     

Interposed autologous nerve segment stimulates nerve regeneration in peripheral nerve allografts in a rat model

The ability of autologous nerve segments interposed between allografts, to increase the total nerve-gap distance, was studied. Sciatic nerve allografts were carried out in a rat model. A 15-mm nerve gap was repaired with a 25-mm nerve graft (interposed group: allo-auto-allograft; control group: allo-allo-allograft). Cyclosporin was given for 12 weeks. Nerve regeneration was evaluated using the weight of the anterior tibial muscle and histologic, morphometric and immunohistochemical analyses at 12, 13, 14, 15, 16, 20, and 24 weeks. Nerve regeneration in the interposed group was statistically significantly better than that in the control group. The authors concluded that a nerve allograft with interposed autograft may enhance nerve regeneration in this model, because of the migration of host-derived Schwann cells into the graft from not only the proximal and distal host nerve stumps, but also the interposed autograft.