Results of clinical evaluation of a new screening method for determining the individual normal level of intraocular pressure

The paper presents the results of practical application of a new screening method for determining tolerant intraocular pressure (TIOP) on a Blood Flow Analyzer (Paradigm, USA). Studies were conducted on 331 eyes (205 subjects). Group 1 consisted of 80 patients (126 eyes) without glaucoma being found, with intraocular pressure (IOP) in the average normal range, but with a TIOP excess of 1-8 mm Hg (a risk group); Group 2 included 15 subjects (20 eyes) without glaucoma with normal IOP in whom TIOP exceeded the existing IOP by 1-7 mm Hg; Group 3 comprised 110 patients (185 eyes) with Stage I-III primary open-angle glaucoma (POAG) with compensated IOP. Morphofunctional studies revealed glaucoma in 95 (75%) eyes in the risk group: Stages II and I in 61 and 30%, respectively; and advanced glaucoma in 9%. At the same time, there was a close correlation of the probable detection of glaucoma with the existing degree of a TIOP excess. No cases of glaucoma were observed in Group 2. The determination of TIOP and morphofunctional changes over time in Group 3 revealed a stable glaucomatous process in 99% of cases in which IOP was lower than or equal to TIOP, as well as progressive glaucomatous neuropathy in 91% in which compensated LOP exceeded TIOP. The results of the study in Group 3 suggest that the index TIOP may be used as a guide of IOP in the treatment and monitoring of POAG. The presented data indicate that the determination of the level of TIOP is a required element of both standard ophthalmological examination and monitoring of glaucoma.     

Comparative estimation of a new empirical formula for the calculation of the focal power of intraocular lenses in the short anteroposterior axis of the eye

This comparative clinical study has indicated the importance of correctly choosing a formula to calculate the focal power of an intraocular lens (IOL) in the short ocular anteroposterior axis (APA). The most accurate and comparable formulas SRK II and SRK/T at the mean ocular APA values have significant errors at an APA of less than 21 mm. The new empirical formula allows the accuracy of calculation of the focal power of IOL to be increased in the short ocular APA as compared with other currently used formulas.     

The role of tear acidity and Cu-cofactor of lysyl oxidase activity in the pathogenesis of keratoconus

Detailed analysis of copper compounds migration in the corneal stroma are presented. The biochemical conditions of the middle periphery of the cornea is found to inhibit copper ions movement to the center in patients with keratoconus due to increased tear alkalinity. Low concentration of dichlorocuprate (I) ion in the center of cornea results in inactivation of lysyl oxidase, an enzyme that catalyzes collagen cross-linking, and thus promotes keratoconus. Revealed association of tear acidity and copper distribution in cornea offers new opportunities in pathogenic treatment of keratoconus.     

A method of surgical correction of myopia by fashioning a new optically active epithelial surface: keratoepitheliomileusis.

A new form of refractive keratoplasty for the correction of myopia was developed using a new approach to the problem. The midperipheral annular area of the recipient cornea was deepithelialized, and Bowman's layer was removed using a special bore coated with diamond crumbs. A cryolathed annular graft was placed on this prepared midperipheral area of the recipient cornea concentrically with its center. As a result of subsequent reepithelialization inside the transplanted ring, a regular optically active surface was formed. The refractive effect gradually appeared eight to ten weeks after surgery This new optically active surface acted as a lens, consisting of epithelial cells on top of the host cornea. The method required neither cutting of the stroma nor any manipulation in the optical zone of the cornea. A new term "keratoepitheliomileusis" was coined for this new procedure. Eleven patients (12 eyes) with high myopia ranging from 7.5 to 22.0D underwent keratoepitheliomileusis. The refractive and visual results found after four to 16 months of follow-up are presented. Emmetropic refraction occurred in three patients. In the other nine eyes, the deviation from emmetropia ranged from 0.75 to 2.5D. In all patients, uncorrected visual acuity was improved considerably (up to 0.3 to 1.OD) without loss in their best-corrected vision.     

短期的脱氢表雄酮治疗增加中年男性受试者的血小板cGMP产生

目的临床和人群研究提示,脱氢表雄酮和它的硫酸盐在抗动脉粥样硬化和冠心病中起保护作用。然而,这种作用的机制仍不清楚。最近报道,硫酸脱氢表雄酮通过增加一氧化氮的生成来延缓动脉粥样硬化的形成。方法24岁的男性受试者(年龄65.4±0.7岁;范围58.2~67.6岁)经盲法安慰剂对照研究,使用脱氢表雄酮(每天50 mg睡前口服)或安慰剂2个月。2个月前和2个月后评价血小板环一磷酸鸟苷(cGMP)浓度(作为一氧化氮产生的标记)和血清中硫酸脱氢表雄酮钠、脱氢表雄酮、胰岛素样生长因子1、胰岛素、葡萄糖、雌二醇、睾酮、纤溶酶原激活物抑制剂1抗原、高半胱…     

Carbonyl iron therapy for iron deficiency anemia

To determine if elemental carbonyl iron powder is safe and effective therapy for iron deficiency anemia, 20 nonanemic and 32 anemic volunteers were studied. Single doses of 1,000 to 10,000 mg of carbonyl iron (15 to 150 times the 65 mg of iron in the usual dose of ferrous sulfate) were tolerated by nonanemic volunteers with no evidence of toxicity and only minor gastrointestinal side effects. Anemic volunteers (menstruating women who had previously donated blood) were treated with several regimens providing 1,000 to 3,000 mg of carbonyl iron daily in one to three doses for 8 to 28 days. After 12 weeks anemia was corrected in 29 of 32 patients, and serum ferritin was greater than 12 micrograms/L in 14. Hemoglobin regeneration proceeded at a rate similar to that described for therapy with oral iron salts and parenteral iron dextran. There was no evidence of hematologic, hepatic, or renal toxicity, but mild gastrointestinal side effects occurred in a majority of anemic volunteers. Carbonyl iron is an effective, inexpensive treatment for iron deficiency anemia, is accompanied by tolerable side effects and may have an advantage over therapy with iron salts by substantially reducing or eliminating the risk of iron poisoning in children.     

Mechanisms involved in the regulation of bovine pulmonary vascular tone by the 5-HT1B receptor

Background and purpose:

5-HT_1B receptors may have a role in pulmonary hypertension. Their relationship with the activity of BK_Ca, a T-type voltage-operated calcium channel (VOCC) and cyclic nucleotide-mediated relaxation was examined.

Experimental approach:

Ring segments of bovine pulmonary arteries were mounted in organ baths in modified Krebs–Henseleit buffer (37^oC) under a tension of 20 mN and gassed with 95% O₂/5% CO₂. Isometric recordings were made using Chart 5 software.

Key results:

Contractile responses to 5-HT (10 nM–300 µM) were inhibited similarly by the 5-HT_1B receptor antagonist SB216641 (100 nM) and the T-type VOCC blockers mibefradil (10 µM) and NNC550396 (10 µM) with no additive effect between SB216641 and mibefradil. Inhibition by SB216641 was prevented by the potassium channel blocker, charybdotoxin (100 nM). 5-HT_1B receptor activation and charybdotoxin produced a mibefradil-sensitive potentiation of responses to U46619. Bradykinin (0.1 nM–30 µM), sodium nitroprusside (0.01 nM–3 µM), zaprinast (1 nM–3 µM), isoprenaline (0.1 nM–10 µM) and rolipram (1 nM–3 µM) produced 50% relaxation of arteries constricted with 5-HT (1–3 µM) or U46619 (30–50 nM) in the presence of 5-HT_1B receptor activation, but full relaxation of arteries constricted with U46619, the 5-HT_2A receptor agonist 2,5 dimethoxy-4 iodoamphetamine (1 µM) or 5-HT in the presence of 5-HT_1B receptor antagonism. Enhanced relaxation of 5-HT-constricted arteries by cGMP-dependent pathways, seen in the presence of the 5-HT_1B receptor antagonist, was reversed by charybdotoxin whereas cAMP-dependent relaxation was only partly reversed by charybdotoxin.

Conclusions and implications:

5-HT_1B receptors couple to inhibition of BK_Ca, thus increasing tissue sensitivity to contractile agonists by activating a T-type VOCC and impairing cGMP-mediated relaxation. Impaired cAMP-mediated relaxation was only partly mediated by inhibition of BK_Ca.