[Dry eye syndrome]

Dry eye syndrome is a multifactorial disorder of the tear film and ocular surface that results in eye discomfort, visual disturbance, and often ocular surface damage. Studies suggest that the prevalence of clinically diagnosed dry eye syndrome [DES] is 0.4%. to 0.5%, which is highest among women and the elderly. The burden of DES can be substantial, affecting visual function, daily activities, social and physical functioning, work place productivity and quality of life. This article discusses the normal anatomy and physiology of the lacrimal functional unit and tear film; pathophysiology of DES; DES etiology; classifications and risk factors; and DES diagnosis and management

Inhibitory effects of thymoquinone, the major component of Nigella sativa l. seeds, on spontaneous and evoked contractions of guinea pig isolated ileum

It has been recently shown that essential oil of Nigella sativa seeds and its major constituent, thymoquinone [TQ], possess relaxant activity on isolated trachea and ileum. Several mechanisms have been suggested to explain the smooth muscle relaxant effects of the essential oil of Nigella sativa seeds. But, only in one study, it has been shown that TQ exerts its relaxant activity probably through the inhibition of histaminergic and serotonergic receptors. Objective: This study was carried out in order to further evaluating the mechanism [s] of muscle relaxant activity of TQ. Tension recording technique using an isometric transducer connected to a physiograph in an organ bath set up was used. The spontaneous contractions of isolated ileum and contractile responses evoked by acetylcholine [Ach], histamine [His], potassium chloride [KC1], and repetitive electrical field stimulation [EFS], were recorded. ACh [10 pM], His [100 HM], KC1 [10 mM], and EFS [20 Hz, 0.2 ms, 130 V], were applied before and after adding TQ [10, 20, 40, 80,100 micro M]. Moreover, in order to evaluate the role of Ca[2+]-channels in TQ-induced relaxation of ileum, the amplitude of contractions evoked by EFS were recorded in the presence and absence of TQ [80 micro M], in Ca[2+]-free Krebs solution, as well as following adding of cumulative concentrations of CaCl[2] [0.1, 0.2, 0.4,1,2 mM]. The results showed that TQ at the minimum concentration of 20

decreased the amplitude of spontaneous contractility [p<0.01] and His- and EFS- evoked contractions [p<0.05]. Also, the amplitude of ACh- and KC1 - evoked contractions were decreased by TQ at the minimum concentration of 40 micro M [p<0.01 and p<0.001, respectively]. The maximum inhibitory effects of TQ against ileum contractility were achieved by the concentration of 100 micro M. Furthermore, the cumulative concentrations of CaCl[2] in the presence of TQ [80 micro M], failed to increase the amplitude of contractions induced by EFS, which were suppressed in Ca[2+]-free medium. These findings indicated that TQ possesses inhibitory effects on contractility of guinea pig isolated ileum, and that effects may be responsible for the smooth muscle relaxant activity of Nigella sativa seeds. The mechanism by which TQ relaxes ileum contractility was exerted, at least in part, through an antagonistic activity on calcium channels in guinea pig ileum smooth muscle cells

[ case of tuberous sclerosis with ocular involvement]

To report multiple astrocytic hamartomas in a patient with tuberous sclerosis [TS]. A 16-year-old girl with TS without any ocular complaint was referred for ophthalmologic examination. She had popular rash on her face and other skin lesions elsewhere in the body which were specific for TS. Multiple well-circumscribed elevated lesions characteristic of astrocytic hamartoma were seen in the retina of both eyes. Two larger nodular and calcified masses, one in inferotemporal retina of the left eye and another in superotemporal retina of the right eye were also detected. One of these lesions was located in far periphery. One of the retinal masses in our patient was located in the far periphery of the retina which is in contrast to previous reports that mention a maximum of 2 disc diameter distance from the optic disc for such lesions. Because of high probability of eye involvement, all cases of TS should undergo a thorough ocular examination

[Cardiovascular effects of five native plants from southern of Khorasan state]

Traditionally, medicinal plants have been used to treat many diseases. To investigate the effects of different plants extract on cardiovascular system, five native southern Khorasan plants were used. Different concentration from the decoction of ziziphora, achillea millefolium [A.M] and aqueous extract of valeriana officinalis [V.O], viola and peganum harmala [P.H] were made]. Animals, Male Sprague Dawley rats [200-250 g, n=25] were anaesthetized with sodium thiopental [30 mg/kg, i.p.], then systemic arterial blood pressure [systolic, diastolic and mean] was measured. Mean arterial blood pressure was 140 +/- 5 mmHg. Intravenous administration of extract reduced the arterial blood pressure [eg. Administration of 0.03 mg/kg of aqueous extract of valeriana officinialis changed the blood pressure from 140 +/- 5 to 77 +/- 10 mmHg, P<0.0001]. There was a non-significant bradycardia with the administration of this extract. These results show that extract of ziziphora, V.O and A.M have hypotensive effects in the control rats and the most potent is V.O. By attention to non significant effect of these extract on heart rate, it is suggested that their hypotensive effect is induced by depletion in peripheral vascular resistance. For investigate of possible mechanism on vascular resistance, the isolated thorasic aorta rings in male rat were used. Therefore in another sets of experiments, after measuring blood pressure, chest was expanded and thoracic aorta was removed and cut into rings [3-4 mm]. Aqueous extract of V.O, in isolated aortic rings which was contracted by phenyl ephrin relaxed. Incubation of tissue with L-NAME [10[-5] molar] for 20 minutes significantly increased the response to different concentration of extract. Thus the vasodilatory mechanism of V.O is nondependent endothelium manner but it accomplish by vascular smooth muscle relaxation. In future, the effects of these extracts will be studied in the hypertensive rats, so that in case obtaining the same results and safety proof, these studied in the hypertensive rats, so that in case obtaining the same results and safety proof, these extracts on other systems, we can recommend take of these plant accompaniment by other treatment

[Effects of protein kinase C inhibitor on the responses to the vasodilator agents in the isolated aorta and mesenteric bed from hypertensive rats]

Numerous in vitro studies indicate that endothelium-mediated relaxation is reduced with development of hypertension. Considering the role of protein kinases in many metabolic processes of phosphate transferring and its importance in the cell communication and function [in the physiological and pathological states] and also the absence of any reports on the effects of these enzymes in the mediating responses to vasodilators during hypertension, this study became of interest. The objectives of this study were to measure the vascular responses to acetylcholine [ACh] and sodium nitroprusside [SNP] in the isolated rat aorta and mesenteric bed removed either from hypertensive or control rats and also to investigate the role of protein kinase C in these responses. Hypertension was induced in the male Sprague-Dawley rats [200-250 g] by DOCA-salt injection [20 mg/kg, twice weekly, for 5 weeks, s.c.] and NaCl [1%] was added to their drinking water. Control rats received saline injection [0.5 ml/kg, twice weekly, for 5 weeks, s.c.]. 5 weeks later, animals were anaesthetized with thiopental [30 mg/kg, i.p.], and arterial blood pressure was directly measured. Mean arterial blood pressure in control and hypertensive rats were: 98+/-7.5, 163 +/- 3.5, mmHg, respectively [P < 0.0001]. In in vitro studies, rings of descending aorta were cut and mounted for isometric tension recording in an organ chamber containg Krebs solution. After 1 h of stabilization, rings were precontracted with phenylephrine [5 x or 1 0-6 or 10-6 M], then concentration response curve to acetylcholine [ACh,-10-6 - 10-3 M] and SNP -10-8 - 10-4 M] were constructed. There was a significant decrease in response to Ach and also a reduction in the maximal response in rings isolated from hypertensive rats. Mesenteric beds were also removed either from control or hypertensive rats and perhsed with Krebs solution. After 1 h of stabilization, tissue were precontracted with norademalin M], then concentration-response curve to ACh [l0-8 - 10-4 M] and SNP [l0-8 - 10-4 M] were constructed. Responses to ACh but not to SNP were significantly reduced in tissue removed from hypertensive rats [eg. in response to l0-6 M of ACh: control: 41.6 +/- 4.9 hypertensive: 17.2 +/- 3.6 mmHg, P < 0.05]. However, addition of chelerythrine [l0 micro M], a protein kinase C [PKC] inhibitor, to the organ bath significantly restored these impaired responses. These results suggest that protein kinase C is involved in the endothelial dysfunction induced by hypertension

[ effects of genistein, a tyrosine kinase inhibitor, on acute and chronic inflammation in diabetic mice]

The effects of tyrosine kinases on acute and chronic inflammation during diabetes are not fully determined. Therefore, the present study focuses on investigating the effects of genistein, a tyrosine kinase inhibitor, on acute and chronic inflammation in diabetic mice. The mice either received normal saline [control, 0.1 ml, i.p., n=144] or were injected with streptozotocin [diabetic, STZ, 200 mg kg -1, i.p., n=144]. By injecting carrageenan and implanting 2 cotton pellets [a week after the injection of saline or STZ] we induced acute and chronic inflammation. Before injecting carrageenan or 5 day after implantation, 9 mice from each group [control or diabetic] received genistein [10 mg kg -1, i.p.], indomethacin [2 mg kg -1, i.p.] or L-NAME [0.1 mg kg -1, i.p.]. Paw edema and the weight of cotton pellets were significantly higher in diabetic mice. Pretreatment with either indomethacin or L NAME significantly reduced the acute and chronic inflammation in the diabetic group. Genistein reduced chronic inflammation significantly [P<0.0001]. These results suggest that activation of tyrosine kinases as well as prostaglandins and nitric oxide pathways are involved in the increased chronic inflammatory responses observed in the diabetic animals

[ comparative study on the dentin thickness under proximal carious in bitewing radiographs and tooth structure]

Background and aim: carious lesions are generally Sound by dentists, using bitewing, [B.W] radiographs and according to the observed depth of lesions, the treatment plan is designed. Although this Technique is presently the most accepted and common one, due to the use of new high speed films with broad density and high voltages, there are some errors in determining the depth of proximal carious lesions. The goal of this study was to compare dentin thickness under proximal caries in bitewing radiography and tooth structure

Materials and Methods: twenty - five tooth samples, consisting of 20 proximal carious lesions, were selected. Prior to and after caries removal, B.W radiographs were taken. Then, radiographs were investigated by two specialists, [Radiology and Operative Dentistry] and dentin thickness under caries were measured using a probe. Each tooth was then sectioned occluso gingivally and the thickness of dentin under proximal caries, on B.W radiographs and tooth structure, were measured by computer. Five healthy teeth were used as controls and 2 bitewing radiographs, before and after cavity preparation, were taken and dentin thickness were also measured. The data were subjected to t-test

Results: mean dentin thickness in tooth structure was % 57 of its mean thickness in bitewing radiography, showing a %42 reduction

Conclusion: more care should be paid while applying bitewing standard technique and its interpretation. Clinical examinations should also be performed under ideal conditions