Roles of prostaglandin E receptors in mesangial cells under high-glucose conditions.

BACKGROUND: High glucose reportedly stimulates prostaglandin (PG) E2 production and DNA synthesis in mesangial cells (MCs). However, the pathophysiological significance of PGE2 in MCs has remained unclear. METHODS: The effects of prostanoids on [3H]-thymidine uptake and cAMP production in rat MCs cultured with 5.6 mM glucose, 25 mM glucose, or 5.6 mM glucose supplemented with 19.4 mM mannitol were examined. The gene expression of PGE2 receptor (EP) subtypes in MCs was analyzed with Northern blotting techniques. RESULTS: Northern blotting indicated EP1 and EP4 gene expression in MCs. EP1 agonists and PGE2 stimulated [3H]-thymidine uptake in MCs. EP1 antagonists dose dependently attenuated high-glucose-induced [3H]-thymidine uptake, which suggests EP1 involvement, by an increase in intracellular Ca2+, in DNA synthesis of MCs. On the other hand, forskolin, db-cAMP, and 11-deoxy-PGE1, an EP4/EP3/EP2 agonist, significantly decreased DNA synthesis in MCs. These inhibitory effects are thought to be mediated via EP4 as a result of an increase in cAMP synthesis. The effects via EP4 seem to be particularly important because PGE2-induced cAMP synthesis was significantly attenuated in the high-glucose group compared with the mannitol group, in which [3H]-thymidine uptake did not increase in spite of augmented PGE2 production. CONCLUSION: The increase in DNA synthesis in MCs under high-glucose conditions can be explained, at least in part, by the high-glucose-induced inhibition of cAMP production via EP4, which augments EP1 function in conjunction with the overproduction of PGE2.     

Relationship of renal lesions with urinary protein excretion in patients with overt diabetic nephropathy]

We investigated the relationship of renal lesions with the degrees of proteinuria in 57 type 2 diabetic patients with overt proteinuria (urinary protein excretion rate (UP) > 0.5 g/day). Creatinine clearance (Ccr) ranged from 25.4 to 131.0 ml/min/1.73 m2. Kidney specimens were obtained and the diagnosis of diabetic nephropathy was made in all patients. The degree of each of the following histologic changes were evaluated: diffuse or nodular lesion, the type of nodular change, mesangiolysis, arteriolar hyalinosis and interstitial damage. We divided the patients into the following 4 groups according to Ccr and UP: group A with Ccr > 60 and UP > 3 g/day (n = 10), group B with Ccr > 60 and UP < 3 g/day (n = 10), group C with Ccr < 60 and UP > 3 g/day (n = 23) and group D with Ccr < 60 and UP < 3 g/day (n = 14), and compared the histologic parameters among the 4 groups. Diffuse index in group A was greater than those in group B (p = 0.05), while those in groups C and D were not different. Nodular index, percentage of patients with nodular lesion did not differ among the 4 groups, however the percentage of glomeruli with complicated nodules (nodular lesion with mesangiolysis and/or microaneurysm) in group C was greater than those in group D (p < 0.05). Hyalinosis index did not differ between group A and B, nor between group C and D, respectively. Interstitial index in group A and B did not differ, however that in group C was greater than in group D (p < 0.05). In addition, the rate of Ccr decrease between renal biopsy and after 12 months was significantly greater in group A and C than in group B and D, respectively (both p < 0.01). These results suggest that 1) mesangial expansion was associated with the degree of proteinuria in patients with slight impaired renal function, 2) tubulointerstitial involvement was associated with the degree of proteinuria in patients with advanced impaired renal function, and 3) these structural changes might be associated with decrease in renal function in diabetic nephropathy.     

Morphological effects on in-stent restenosis assessed by intravascular ultrasound imaging.

The purpose of this study was to evaluate the rupture and dissection of the vessel wall immediately after balloon dilatation by intravascular ultrasound (IVUS) imaging and to predict restenosis in patients who underwent subsequent coronary stent implantation. Stent implantation improves the long-term results of coronary angioplasty by reducing lesion elastic recoil and arterial remodeling. However, several studies have suggested that neointimal hyperplasia is the cause of instant restenosis. We recruited 60 patients in whom IVUS studies were performed immediately after successful balloon dilatation and just before stent implantation. We compared IVUS parameters with 6-month follow-up quantitative coronary angiography. This was performed in 51 lesions of 51 patients (85%). Qualitative analysis included assessment of plaque composition, plaque eccentricity, plaque fracture and the presence of dissection. In addition, minimal luminal diameter, percent diameter stenosis, percent area stenosis and plaque burden were quantitatively analyzed. Two morphological patterns after balloon dilatation were classified by IVUS. Type I was defined as absence or partial tear of the plaque without disclosure of the media to lumen (22 lesions). Type II was defined as a split in the plaque or dissection of the vessel wall with disclosure of the media to the lumen (29 lesions). At 6 months follow-up, angiographic restenosis occurred in 17 of the 51 lesions (33%). Restenosis was significantly (p < 0.05) more likely to occur in type II (13/29: 45% incidence) than in type I (4/22: 18% incidence). The assessment of plaque morphology immediately after balloon dilatation and before stent implantation provides important therapeutic and prognostic implications.     

Cerebral blood flow responses to somatosensory stimulation are unaffected by scopolamine in unanesthetized rat.

Studies with positron-emission tomography have indicated that muscarinic acetylcholine receptors may be involved in the mechanism of enhancement of cerebral blood flow (CBF) by neuronal functional activation. We examined the effects of muscarinic receptor blockade by scopolamine on the local CBF responses to vibrissal stimulation in the whisker-to-barrel cortex sensory pathway in unanesthetized rats. Local CBF was measured by the quantitative autoradiographic [(14)C]iodoantipyrine method. Scopolamine (0.4 or 0.8 mg/kg) was injected i.v. 30 min before measurement of local CBF; control rats received equivalent volumes of physiological saline. Vibrissae on the left side of the face were stroked continuously throughout the 1-min period of measurement of CBF. Local CBF was determined bilaterally in four structures of the pathway, i.e., spinal and principal sensory trigeminal nuclei, ventral posteromedial thalamic nucleus, and barrel field of the sensory cortex, as well as in four representative structures unrelated to the pathway. The higher dose of scopolamine raised baseline CBF in the two trigeminal nuclei, but neither dose diminished the percentage of increases in local CBF because of vibrissal stimulation in any of the stations of the pathway. These results do not support involvement of muscarinic receptors in the mechanism of enhancement of local CBF by functional neuronal activation, at least not in the whisker-barrel cortex sensory pathway in the unanesthetized rat.     

Prognostic utility of myocardial blood flow assessed by N-13 ammonia positron emission tomography in patients with idiopathic dilated cardiomyopathy.

Previous studies in patients with idiopathic dilated cardiomyopathy (IDC) have suggested that myocardial perfusion is impaired and spatially heterogeneous in such cases. Our objective was to identify any association between an abnormality in myocardial perfusion and the prognosis of patients with IDC. We collected data on N-13 ammonia positron emission tomography (PET) studies performed in 26 patients with IDC (9 nonsurvivors, 17 survivors) and in 8 normal control subjects. Regional myocardial blood flow (rMBF) was quantified using N-13 ammonia positron emission tomography and the Simple flow model. The spatial heterogeneity of myocardial perfusion was assessed by calculating the coefficient of variance of rMBF. Mean rMBF of the survivors was significantly lower (0.54 +/- 0.13 ml/min/g) than that of control subjects (0.66 +/- 0.06 ml/min/g) (p = 0.03 vs control), but did not differ significantly between nonsurvivors (0.58 +/- 0.15 ml/min/g) and control subjects. The coefficient of variance of rMBF was significantly higher in nonsurvivors than in either survivors or control subjects (0.24 +/- 0.08 vs 0.15 +/- 0.08, p = 0.007, and 0.16 +/- 0.05, p = 0.03, respectively). The probability of 3-year survival (Kaplan-Meier method) was 33.0% in subjects whose coefficient of variance of rMBF was above the median compared with 90.0% in subjects whose coefficient of variance of rMBF was below the median (p = 0.01). The probability of 3-year survival did not differ among subjects whose mean rMBF was above versus below the median (61.5% vs 62.9%, respectively). The results suggest that the prognosis of patients with IDC is associated with the spatial heterogeneity of myocardial perfusion, not with initial absolute rMBF.     

Investigation of the time delay between variations in heart rate and blood pressure

Relationships between fast variations in heart rate and blood pressure are known mainly to reflect parasympathetic activity. To assess parasympathetic function, relationships are investigated using a mutual information analysis, by assuming an information channel between blood pressure (BP) and inter-R-wave interval (RR) derived from the electrocardiogram. The differential sequences of BP and RR are coded into ‘alphabets’ for analysing fast variations. The averaged mutual information (AMI) is obtained as a function of delay d (beats) of the differential sequence of RR with reference to BP. The AMIs for supine and standing positions are compared. For 23 patients with renal failure, the AMI against d shows posture-independent and delayed-transfer characteristics from fast variations in BP to those in RR. The closest relationship is found with a 2-beat delay with an out of phase relationship. The 28 control subjects exhibit the 2-beat delayed transfer characteristics in the standing position, but are almost synchronous in the supine position. The mutual information analysis of the delay between fast variations in BP and PR explicitly shows a deficit in the parasympathetic regulation in the patients with renal failure.     

Freehand cryopreserved mitral valve allograft with flexible ring in the pig.

OBJECTIVE: Cryopreserved valve allografts have proven satisfactory in aortic and pulmonary positions but not mitrally because of the difficulty in properly aligning the mitral valve allograft due to the complex subvalvular apparatus. To make the surgical procedure easier, we developed a freehand cryopreserved mitral valve allograft with a flexible ring. METHODS: Whole cryopreserved mitral valve allografts with the papillary muscle, chordae, and leaflets from donor pigs were implanted mitrally in recipient pigs under cardiopulmonary bypass divided into 2 experimental groups; control allografts without the ring (n = 6) (CA group) and allografts with a flexible ring (n = 7) (RA group). Postimplantation hemodynamics and valvular function were evaluated by measuring arterial pressure, left ventricular end diastolic pressure, and left atrial pressure and by evaluating 2-dimensional echocardiography. Allografts were evaluated pathohistologically after cryopreservation and surgery by light microscopy. RESULTS: Hemodynamics did not differ significantly between groups. Aortic cross-clamping and Cardiopulmonary bypass times were significantly shorter in the RA group than the CA group (p < 0.05). Pigs requiring optional procedures with sutured annuloplasty and valvuloplasty numbered more in the CA group than the RA group. Postoperative echocardiography showed satisfactory mitral valve opening in diastole and good leaflet coaptation in systole in both groups. Light microscopic examination of cryopreserved allografts after surgery showed almost normal structures. CONCLUSIONS: Acute hemodynamic function and morphology of freehand cryopreserved valve allografts implanted mitrally in pigs proved acceptable. Adaptation of the flexible ring to allografts might be useful for technical benefit to facilitate accurate positioning of mitral subvalvular apparatus at implantation.     

A case of LGMD2A identified with both western blot analysis and immunostaining of calpain 3 in biopsied muscle]

A 45-year-old housewife had proximal dominant limb muscle weakness from around 25 years of age. Her parents were cousins. None of family members was affected. Progressive muscle weakness and atrophy were prominent at the posterior compartments of legs and trunk. Serum CK was moderately elevated. Muscle pathology revealed variation in fiber size, moderate increase in numbers of internal nuclei and abundant lobulated fibers. On immunostaining using by monoclonal antibody against human calpain 3 (NCL-CALP-2 C4; Novocastra) to the biopsied muscle, calpain 3 was completely absent in the sarcoplasm, while granular debris and in part positive striation were noted in control muscle. By Western blot analysis, a band corresponding to 94 kDa of calpain 3 was not detected. A genetic analysis of calpain 3 revealed homozygous C-565-G mutation (Leu189Val). From the present study. Western blot analysis and immunostaining by using calpain 3 antibody were suggested to be useful to diagnose LGMD2A in LGMD patients.     

Evaluation of topotecan monotherapy for relapsed small-cell lung cancer after amrubicin monotherapy failure

Objective: The utility of topotecan monotherapy for relapsed small-cell lung cancer (SCLC) after failure of amrubicin monotherapy has not been evaluated. We aimed to investigate the efficacy and safety of topotecan monotherapy in patients with relapsed SCLC after amrubicin monotherapy.Patients and Methods: We retrospectively analyzed data from 16 patients with relapsed SCLC who were treated with topotecan monotherapy after amrubicin monotherapy at our hospital.Results: The response rate, progression-free survival, and overall survival were 0%, 32.5 days (95% confidence interval [CI] = 18–51), and 112 days (95% CI = 55–267), respectively. The most common adverse events (grade ≥3) were leukopenia (31.3%) and thrombocytopenia (31.3%), followed by anemia, anorexia, edema, and lung infections.Conclusion: The efficacy of topotecan monotherapy for relapsed SCLC after amrubicin monotherapy is inconclusive. Therefore, further studies are warranted.