Alterations of vascular smooth muscle function have been implicated in the development of vascular complications and circulatory dysfunction in diabetes. However, little is known about changes in smooth muscle contractility and the intracellular mechanisms contributing to altered responsiveness of blood vessels of diabetic patients. Therefore, smooth muscle and endothelial cell function were assessed in 20 patients with diabetes and compared with 41 age-matched control subjects. In rings from uterine arteries, smooth muscle sensitivity to K+, norepinephrine (NE), and phenylephrine (PE) was enhanced by 1.4-, 2.3-, and 9.7-fold, respectively, and endothelium-dependent relaxation was reduced by 64% in diabetic patients, as compared with control subjects. In addition, in freshly isolated smooth muscle cells from diabetic patients, an increased perinuclear Ca2+ signaling to K+ (30 mmol/l >73%; 60 mmol/l >68%) and NE (300 nmol/l >86%; 10 micromol/l >67%) was found. In contrast, subplasmalemmal Ca2+ response, which favors smooth muscle relaxation caused by activation of Ca2+-activated K+ channels, was reduced by 38% in diabetic patients as compared with control subjects, indicating a significant change in the subcellular Ca2+ distribution in vascular smooth muscle cells in diabetic patients. In contrast to the altered Ca2+ signaling found in freshly isolated cells from diabetic patients, in cultured smooth muscle cells isolated from control subjects and diabetic patients, no difference in the intracellular Ca2+ signaling to stimulation with either K+ or NE was found. Furthermore, production of superoxide anion (*O2-) in intact and endothelium-denuded arteries from diabetic patients was increased by 150 and 136%, respectively. Incubation of freshly isolated smooth muscle cells from control subjects with the *O2- -generating system xanthine oxidase/hypoxanthine mimicked the effect of diabetic patients on subcellular Ca2+ distribution in a superoxide dismutase-sensitive manner. We conclude that in diabetic subjects, smooth muscle reactivity is increased because of changes in subcellular Ca2+ distribution on cell activation. Increased *O2- production may play a crucial role in the alteration of smooth muscle function.

Action potential recordings from isolated guinea pig ventricular cells in the whole-cell recording mode were used to study the toxic and photodynamic properties of the voltage-sensitive fluorescent dye di-4-ANEPPS. Staining of the cardiomyocytes with di-4-ANEPPS (30 or 60 microM; 10 min) did not alter the action potential shape. When the stained cells were illuminated (1W/cm2) severe effects on the action potential were observed. There was a prolongation of the action potential duration, occurrence of early afterdepolarizations, reduction of the membrane resting potential and eventually inexcitability. Addition of the antioxidant catalase (100 IU/ml) to the extracellular solution delayed the onset of these effects, suggesting that reactive-oxygen-intermediates take part in di-4-ANEPPS induced photodynamic damage. Since di-4-ANEPPS is a very important tool for optical membrane potential recordings in heart tissue and single cardiomyocytes catalase might be useful in suppressing photodynamic damage during optical potential recordings.

1 We used single human atrial myocytes to study I f occurrence, properties and pharmacological modulation. Cells were obtained by chunk enzymatic digestion from samples of right atrial appendages of patients undergoing corrective cardiac surgery. 2 Patch-clamped cells in the whole-cell con®guration were superfused with a modi®ed Tyrode solution to reduce contamination by interfering currents and to amplify I f . The average cell membrane capacitance was 85.06+2.41 pF (n=531). Data were consistent with the geometrical dimensions of the cells (length 94.2+1.89 mm, width 17.9+0.42 mm, n=126). 3 When hyperpolarizing to 7120 mV from a holding potential of 740 mV, 252 of 306 tested cells (82%) expressed a hyperpolarization-activated inward current (I f density =3.77+0.25 pA pF 71 ); the current was considered to be present in a given cell if its density at 7120 mV was larger than 0.5 pA pF 71 . 4 Current activation was sigmoidal and ®tted a Boltzmann model; the average activation curve (n=25) showed a maximum current amplitude of 205.97+19.94 pA, corresponding to 3.87+0.63 pA pF 71 , voltage of half-maximal activation (V 1/2 ) at 786.68+2.19 mV and a slope of 711.39+0.69 mV. The reversal potential of I f measured by tail-current analysis was 713.07+1.92 mV (n=6). The addition of CsCl (5 mM) fully and reversibly blocked the current. 5 In the presence of the b-adrenoceptor agonist isoprenaline (Iso, 1 mM), V 1/2 was signi®cantly shifted toward less negative potentials by 6.06+1.96 mV (n=16, P=0.0039). The selective A 1 -adenosine receptor agonist cyclopentyladenosine (CPA, 1 mM) caused a statistically signi®cant shift of V 1/2 toward more negative potentials with respect to the control curve, both in the absence (77.37+1.83 mV, P=0.0005, n=11) and in the presence of 1 mM Iso (74.97+1.78, P=0.031, n=6). 6 These results demonstrate that a current with the properties of I f described in cardiac primary and secondary pacemakers occurs in the majority of human atrial cells. While the pathophysiological relevance of I f in human atrial tissue remains to be de®ned, our data clearly show that it is modulated through stimulation of b-adrenoceptors and A 1 -adenosine receptors.

all 10 cities including the rural areas of the province of Kerman. All data were finally analyzed by SPSS software (version 11.5). Results On the basis of recorded statistical analysis, the mortality cases of human rabies in the province of Kerman during one decade was 10 persons (eight males and two females). One-half of them (50%) were bitten by dogs and the others (50%) by foxes. Among the reported deaths, 40% were from Kahnooj county (Jiroft region). The reported data indicated that 21,546 persons were bitten by animals during 10 years in the province of Kerman. The mean of age of the people who were bitten by dogs was 24.80 years (SD = ±14.6), while the mean age of the people who were bitten by foxes was 57.25 years (SD = ±1.50). There was a significant difference between the mean age of these two groups of the people (P < 0.05). The most frequent rate of injured people was reported in the age group 10-19 years old and the frequency rate of males (76.00%) was more than females (24.00%). Therefore, there was a statistically significant difference between males and females in this study (P < 0.01). About 60% of all persons that were bitten by animals were from rural areas and 40% of them were from urban areas (P < 0.05). Among the people who were bitten and injured by animals during one decade in the province of Kerman, 85.70% of them were not treated by the rabies prophylaxis treatment regimen. Among all of them who were bitten by animals, 50% were injured through hands and feet, 40% of them through heads and faces, and 10% of them through trunks, cervical regions and other organs of the bodies. In the persons who were bitten by animals in the head region, the mean latency period for rabies was 33 days (SD = ±12.2 days), while the mean latency period in the persons who were bitten through hands and feet was 77 days (SD = ±45.8 days). The P value was <0.1. The results of this study showed that there is a significant reciprocal correlation between annual raining level and the frequency rate of animal bites in the province of Kerman (r = 0.5, P < 0.01). Conclusions According to this study, the role of foxes in the epidemiology of human rabies in the province of Kerman, located in the southeast of Iran, seems very important. Since most of the animal bite individuals, during the one-decade survey in this region of Iran, did not seem aware of the risk of exposure to the viral infection of rabies through animal bites, the public education of preventive measurements of rabies seems imperative by the public health authorities as well as vaccination of animals against rabies, especially dogs and cats, as well as mass vaccination of wild animals by means of distribution of oral vaccines in the vast and scattered forests by helicopters belonging to Veterinary Organization Authorities being recommended. Collaboration of intersectional public health relationships of medical science universities of the province of Kerman as well as all related authorities to control rabies prevalence in the regional and interregional provi...

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