Analysis of a decreased Na+ conductance by tumor necrosis factor in identified neurons of Aplysia kurodai.

The ionic mechanisms of the effect of extracellularly ejected recombinant human tumor necrosis factor-alpha (rhTNF-alpha) on the membrane of identified neurons R9 and R10 of Aplysia kurodai was investigated with conventional voltage-clamp, micropressure ejection, and ion substitution techniques. Micropressure-ejected rhTNF caused a marked hyperpolarization in the unclamped neuron. Clamping the same neuron at it resting potential level (-60 mV) and reejecting rhTNF-alpha with the same dose produced a slow outward current [Io (TNF)] associated with a decrease in input membrane conductance. Io (TNF) was decreased by depolarization and increased by hyperpolarization. The extrapolated reversal potential of Io (TNF) was approximately +10 mV. Ion substitution and pharmacological experiments suggest that Io (TNF) in identified neurons R9 and R10 of A. kurodai is due to a decreased Na+ conductance but not due to an activation of the Na(+)-K+ pump. Our results demonstrate that the immunomodulator TNF can act directly on the nervous system as well as on the immune system.     

An acetylcholine-induced potassium current in tail sensory neurons in the pleural ganglion of Aplysia

Acetylcholine (ACh) induces a hyperpolarization during current clamp and an outward current during voltage clamp in tail sensory neurons of Aplysia kurodai. This response was proved to be produced by a specific increase in membrane permeability toward potassium ions, the cholinergic antagonists, d-tubocurarine chloride (d-TC), and atropine mildly reduced the ACh response, while tetraethylammonium (TEA) most effectively blocked this response. These findings provide evidence that tail sensory neurons have the inhibitory ACh receptor in addition to the known receptors for serotonin (5-HT), small cardioactive peptide B (SCPB), and neuropeptide Phe-Met-Arg-Phe-NH2 (FMRFamide).     

The effect of calcium ion concentration on osteoblast viability, proliferation and differentiation in monolayer and 3D culture

Our research group aims to develop an osteochondral composite using type II collagen gel with hydroxyapatite (HAp) deposited on one side. Soaking gels in Ca2+ and phosphate solution is indispensable to HAp deposition, so relationships between cell behavior and Ca2+ concentration were examined in two- and three-dimensional cultures. The present results indicate that 2-4 mM Ca2+ is suitable for proliferation and survival of osteoblasts, whereas slightly higher concentrations (6-8 mM) favor osteoblast differentiation and matrix mineralization in both 2- and 3-dimensional cultures. Higher concentrations (>10 mM) are cytotoxic. Purely from the perspective of calcium deposition, higher concentrations lead to increased accumulation of Ca2+. Culturing cells in phosphate-containing gel in media with Ca2+ also leads to time-dependent formation of HAp in the gel. Considering the viability of embedded cells, culturing scaffolds in media with Ca2+ concentrations around 5mM is useful for both HAp deposition and osteoblast behavior.     

Effects of exogenous interferon on L cells persistently infected with Sendai virus

Summary A carrier culture of L cells persistently infected with Sendai virus (steady state) designated as L-Sendai_ts cells was established with a temperature-sensitive strain of the virus. When interferon was added to culture fluids from the start of the cultures at permissive (35° C) or non-permissive temperature (38° C), cell-associated infectivity was unaffected at 35° C, while it was unexpectedly enhanced at 38° C, although the cell-associated infectivity was titrated after further incubation at 32° C for 2 days. The titer of cell-associated infectivity was increased by subculturing in the continuous presence of interferon at 38° C. The effect of interferon on the paradoxical enhancement of cell-associated infectivity was shown to be dose dependent. When L-Sendai_ts cells were successively subcultured 6 times at 38° C in the continuous presence or absence of interferon, more than 95 per cent of the cells contained a detectable amount of nucleocapsid (NP) antigen in the presence of interferon, whereas the antigen could be detected in only 30–40 per cent of the cells subcultured in the absence of interferon. Only when the cells subcultured at 38° C in the presence of interferon were transferred to permissive temperature, could the distinct hemadsorbing and cell-associated hemagglutinating activities and the release of virus particles, as measured by hemagglutinating activity in the culture fluids, be detected. Cells subcultured in the presence of interferon accumulated more virus polypeptides than in the absence of interferon. Accumulation of virus specific RNA in the cells subcultured in the presence of interferon was about twice as much as that in the absence of interferon. Larger sized RNA (probably 50S) was the major species and two smaller RNAs could be detected in both the treated and untreated cells.When L-Sendai_ts cells were cultured at 38° C in the presence of interferon, their multiplication was clearly inhibited. However, the cells which were subcultured twice at 38° C in the continouos presence of interferon acquired resistance to the anti-cell proliferative action of interferon. Interestingly, the conversion of the sensitive state to resistant state of the cells was reversible.With 3 Figures     

Causes of visual field defects after vitrectomy]

PURPOSE: An inferotemporal visual field defect sometimes occurs following vitreous surgery for idiopathic macular hole. There is a possibility that this visual field defect is due to damage to the superonasal retina by fluid or air irrigation through an inferonasal infusion port. We tested this hypothesis by placing the infusion port in the inferonasal sector during vitreous surgery. CASES AND METHOD: We performed vitreous surgery on 31 eyes with idiopathic macular hole. The infusion port was placed in the inferonasal sector. The vitreous cavity was replanced either by 20% SF6 or 12% C3F8. We did not abrade the retinal pigment epithelium within the hole. The visual field was assessed before and 1 month after surgery using a Goldmann perimeter. FINDINGS: Three eyes developed a wedge-shaped visual field defect in the inferonasal sector. No visual field defect developed in the other 28 eyes. CONCLUSION: The findings show that visual field defect following surgery for idiopathic macular hole is dependent upon the site of the infusion port. We presume that the visual field defect is consequent to retinal damage caused by the flow of air or fluid during surgery.     

Balloon Dilatation of the Pulmonary Valve in a Patient with Pulmonary Atresia and Intact Ventricular Septum Using a Commercially Available Radiofrequency Catheter

Using a commercially available 5F deflectable radiofrequency catheter, we have succeeded in percutaneous valvotomy of an imperforate pulmonary valve and consecutive balloon dilatation in a baby with pulmonary atresia and intact ventricular septum. After the procedure, right ventricular systolic pressure fell from 125 mmHg to 65 mmHg, and right ventriculography demonstrated anterograde blood flow into the pulmonary arteries. There were no major complications. Doppler echocardiography at 1 year after the procedure demonstrated a pressure gradient across the pulmonary valve of 20 mmHg with mild pulmonary and tricuspid regurgitations.     

Association of Loss of Heterozygosity at the p53 Locus with Chemoresistance in Osteosarcomas

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite insensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 ( p 53) and 13q14 ( Rb ) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p 53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p 53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss ( P <0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p 53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.     

Repair of full-thickness articular cartilage defects using injectable type II collagen gel embedded with cultured chondrocytes in a rabbit model

BACKGROUND: Recently, tissue-engineered chondrocyte transplantation has been tried to treat full-thickness cartilage defects. We developed an injectable type II collagen gel scaffold by chemically reacting type II collagen with polyethylene glycol crosslinker. This type II collagen was prepared from the nasal septa of cattle. In the present study, chondrocytes embedded in type II collagen gel were injected into rabbit full-thickness cartilage defects without a periosteal graft, and the feasibility for clinical application of the gel was evaluated. METHODS: Chondrocytes were isolated from 1-kg New Zealand white rabbits. A full-thickness articular cartilage defect (5 mm diameter, 4 mm depth) was created on the patellar groove of the femur of 16 male 3-kg New Zealand white rabbits. A type II collagen solution of mixed chondrocytes at a density of 1 x 10(7) cells/ml was injected and transplanted into the defect in the right knee. The controls were the defect only in the left knee. At 4, 8, 12, and 24 weeks after operation, four cases from each group were evaluated macroscopically and histologically. RESULTS: After injection into the cartilage defect, the gel bonded to the adjacent cartilage and bone within several minutes. Macroscopic examination revealed that the surface of the transplanted area was smooth and exhibited similar coloration and good integration with the surrounding cartilage at 12 and 24 weeks after transplantation. Histological examination at 8 weeks revealed favorable hyaline cartilage regeneration with good chondrocyte morphology. At 12 and 24 weeks, reparative cartilage remained rich in type II collagen. According to O'Driscoll histological scores, significant differences between the transplanted and control groups were apparent at 12 and 24 weeks. Immunohistochemical staining indicated sufficient type II collagen synthesis in regenerated cartilage 8 weeks after transplantation, and it was maintained until 24 weeks. CONCLUSIONS: These results indicate that type II collagen gel is suitable for injection into cartilage defects without any covering of a graft and offers a useful scaffold during chondrocyte transplantation.     

经睫状体平坦部行颞上或鼻下Baerveldt青光眼植入术的短期临床疗效比较

目的:研究并探讨Baerveldt青光眼植入术(BGI)的不同植入部位对眼压(IOP)的影响。方法:对日本Toho大学Sakura医疗中心接受BGI治疗的新生血管性青光眼的病例进行回顾性分析。所有患者分为两组:颞上植入组(16例患者18眼,其中男性13例,女性3例;平均年龄62.9±14.4岁)和鼻下植入组(15例患者17眼,其中男性11例,女性4例;平均年龄56.9±10.7岁)。术后12mo随访复查。比较两组术后12mo与术前相比的眼压降低率。结果:颞上植入组:术前平均IOP为31.1±10.0 mmHg,术后平均IOP为14.4±4.5 mmHg;鼻下植入组:术前平均IOP为34.9±9.7 mmHg,术后平均IOP为15.9±3.7 mmHg。颞上植入组IOP降低率为(50.0±19.0)%,鼻下植入组降低率为(51.2±16.3)%。两组间无显著统计学差异(t-test,P=0.590)。结论:经睫状体平坦部行颞上或鼻下BGI的短期临床疗效无差异。