[Involvement of Src kinase in the down-regulation of ultra-rapid delayed rectifier K(+)current induced by tumor necrosis factor-α in cardiomyocytes].

Objective: To investigate whether inflammatory factor tumor necrosis factor-α (TNF-α) is involved in the electrical remodeling of cardiomyocytes by regulating ultra-rapid delayed rectifier K(+) current (I(kur)) and the role of Src kinase. Methods: H9c2 cells, embryonic cardiomyocytes of rat, were cultured in Dulbecco's modified Eagle's medium (DMEM) and atrium-derived HL-1 cells were cultured in Claycomb medium. Both H9c2 and HL-1 cells were cultured at 37 ℃ with 5% CO(2). Cells cultured in normal conditions without additional treatment served as control group. Experimental groups were treated with different concentration of TNF-α (25 or 50 or 100 ng/ml) for 24 hours. To study whether Src specific inhibitor PP1 could abrogate the effect of TNF-α, cells were pre-treated with 10 µmol/L PP1 for 1 hour, followed by TNF-α (100 ng/ml) for 24 hours. Western blot and the whole cell patch clamp technique were used to detect the protein expression of Kv1.5 and Src and I(kur) in each group. Results: (1) In H9c2 cells, high concentration of TNF-α treatment (100 ng/ml) significantly reduced the Kv1.5 protein expression compared with control group and TNF-α 25 ng/ml group (both P<0.05). Compared with control group, the expression of p-Src protein was higher in 25 ng/ml, 50 ng/ml, 100 ng/ml TNF-α group (all P<0.05), but there was no statistical difference in the expression of Src protein among groups (P>0.05). In addition, the current density of I(kur) was decreased in 50 ng/ml, 100 ng/ml TNF-α group (both P<0.05). Furthermore, the expression of Kv1.5 protein and the current density of I(kur) were increased in PP1+TNF-α group compared with TNF-α 100 ng/ml group (both P<0.05). There was no statistical difference in the expression of Kv1.5 protein and the current density of I(kur) between the control group and PP1+TNF-α group (both P>0.05). (2) In atrium-derived HL-1 cells, the expression of Kv1.5 protein was reduced in 100 ng/ml TNF-α group compared with control group and TNF-α 25 ng/ml group (both P<0.01). In addition, the expression of p-Src protein was increased in TNF-α 100 ng/ml group compared with control group (P<0.05), but there was no statistical difference in the protein expression of Src among groups (P>0.05). The expression of Kv1.5 protein was increased in PP1+TNF-α group compared with TNF-α 100 ng/ml group (P<0.05). Conclusion: TNF-α is involved in the pathogenesis of atrial fibrillation, probably via decreasing I(kur) current density in atrium-derived myocytes through the activation of Src kinase.

Preparation of monoclonal antibody against human m3 receptor.

AIM: To raise monoclonal antibody against human m3 receptor. METHODS: The m3 receptor selective peptide segments deduced from its gene were chemically synthesized, coupled to keyhole limpet hemocyanin carrier protein, and injected to Balb/c mice to raise monoclonal antibody. Antibody was purified by a combination of two-step precipitation methods and ion-exchange chromatography. The specificity of monoclonal antibody was tested by enzyme-linked immunosorbent assay, immunohistochemistry, and radioligand binding assay of receptors. RESULTS: The monoclonal antibody specifically bound to the protein of rat salivary gland and m3 peptide, but not m4 peptide. In radioligand binding assay of receptors, monoclonal antibody inhibited the binding of 3H-QNB to muscarinic receptor in rat salivary gland, but not in rat heart, and could not inhibit the binding of 3H-PZ to rat brain cerebral cortex membrane protein. Immunohistochemical study showed that the human salivary cell surface was strongly stained, whereas the human heart cell surface was not. CONCLUSION: Highly purified (96.3%) monoclonal antibody against the m3 receptor peptide recognized the m3 receptor.

[Laser suture lysis following trabeculectomy].

Trabeculectomies with tightly sutured scleral flap was performed on 49 eyes of 45 patients with angle closure or open angle glaucomas, the experimental group, of which 41 eyes underwent laser suture lysis subsequently. After a mean period of follow-up 14.7 months (12-36 months), the average intraocular pressure was decreased from pre-operative 5.93 kPa (44.5 mmHg) to post-operative 1.96 kPa (14.7mmHg). The experimental group of patients was compared with the control group, 41 eyes of 39 cases at the same period randomly undergoing trabeculectomy without laser suture lysis. The control rate of intraocular pressure is higher (89.8%:73.2%) and the incidence of ocular complications (such as, shallow anterior chamber, choroid detachment, hyphema, lens opacity) is significantly lower in the former group, showing that trabeculectomy with following laser suture lysis is a safe and effective anti-glaucoma surgery. The advantages, points for attention and experiences of laser suture lysis have been introduced in the paper.

[Prevention of IOP rise following laser iridectomy with topical timolol and indomethacin].

Double-masked study on 40 eyes (40 patients) of primary angle-closure glaucoma demonstrated that topical timolol and indomethacin prevented the IOP rise following combined argon and Nd:YAG laser iridectomy. A combination of the 2 drugs was especially effective in that the number of patients who would have an IOP increase over 1.33 kPa (1 kPa = 7.5 mmHg) above the baseline was reduced by 80%. The mechanism of IOP rise following iridectomy and its prevention were discussed.

[Retinitis pigmentosa associated with glaucoma].

Analysis of 1400 cases of retinitis pigmentosa revealed that (1) 32 cases (2.3%) were associated with glaucoma, of which (2) 30 cases were of the angle closure type; (3) the C/D ratio was normal in over one half of the cases, and in 5 cases the optic disk remained normal after 1/2-5 years of persistent IOP elevation; (4) in 31 cases (97%) the blood pressure was below the norm of equivalent age group; and (5) pathologic examination of the trabecular meshwork in 14 cases showed no excessive pigment deposition to obstruct the outflow channels.

[Primary tracheal carcinoma--report of 5 patients].

From 1980 through 1985, 5 patients with primary tracheal carcinoma were admitted to Human Cancer Hospital, comprising 0.024% of total admissions during the same period. The incidence of lung cancer and laryngeal cancer was 386 and 43 times as high as that of tracheal carcinoma. All were proved pathologically. 3 patients were given radical operation, followed by radiotherapy; 1 received radiotherapy plus chemotherapy and the other, chemotherapy alone. All three patients treated by operation plus radiotherapy survived for more than 3 years and 2 of them are still alive. Diagnosis, causes and avoidance of misdiagnosis are discussed.