Clinical and Histopathological Study of the Effect of Adipose-Derived Mesenchymal Stem Cells on Corneal Neovascularization following Alkali Burn in a Rabbit Model.

The cornea, the transparent part of the eye, performs a significant function in eyesight by refracting the light to focus a visual image. Since the cornea is indispensable for vision, corneal inflammation may induce visual disturbance and blindness. Several investigations have reported that various corneal inflammatory diseases cause visual impairment and chronic inflammation of the cornea, which can lead to blindness. The present study aimed to assess the effect of adipose-derived mesenchymal stem cells (ADMSCs) on corneal healing after alkali injuries. Corneal alkali injuries were induced in the eyes of 20 rabbits. The MSC group (n=10) was treated with subconjunctival injections, while the control group (n=10) was left without any treatment. Rabbits underwent slit-lamp examination and photography and were evaluated for corneal neovascularization. Based on the histological evaluation, the eyes treated with MSCs showed better recovery. Furthermore, the MSC and control groups were significantly different in the degree of corneal neovascularization and re-epithelialization, as well as the elevation of the neovascular tissue at two and four weeks post-surgery.

WITHDRAWN: Incidence and mortality of COVID-19 in Iranian multiple sclerosis patients treated with disease-modifying therapies.

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Gastrointestinal-specific anxiety: an important factor for severity of GI symptoms and quality of life in IBS.

BACKGROUND: Gastrointestinal (GI)-specific anxiety (GSA) has been proposed to influence symptom severity and quality of life (QOL) in patients with irritable bowel syndrome (IBS). The Visceral Sensitivity Index (VSI) is a recently developed, reliable and valid measure of GSA. Our aim was to evaluate the association between GSA, GI symptom severity, and QOL in IBS patients. METHODS: Sixty healthy subjects and 306 patients fulfilling the Rome II criteria for IBS were studied. Demographic and disease-related factors were assessed. Patients completed VSI and GI Symptom Rating Scale (GSRS) and questionnaires to determine psychological symptom severity (Hospital Anxiety and Depression Scale), QOL (Short form 36), and presence of functional GI disorders (Rome II Modular Questionnaire). KEY RESULTS: Compared with healthy subjects, patients with IBS had more severe GSA (34.7 +/- 16.9 vs. 2.2 +/- 4.4 [mean +/- standard deviation]; P < 0.0001). In the IBS group, more severe GSA was seen in patients with more severe GI symptoms (P < 0.0001), general anxiety (P < 0.0001) and depression (P < 0.0001), and with lower socioeconomic status (P < 0.05). In a regression analysis, GSA was the strongest predictor for GI symptom severity (GSRS total score), followed by number of Rome II diagnoses, presence of meal-related IBS symptoms, and gender (R(2) = 0.34). Gastrointestinal-specific anxiety was also, together with general anxiety, depression, socioeconomic status, and gender, found to be independently associated with mental QOL (R(2) = 0.62). CONCLUSIONS & INFERENCES: Gastrointestinal-specific anxiety seems to be an important factor for GI symptom severity and QOL in patients with IBS.

Heightened central affective response to visceral sensations of pain and discomfort in IBS.

BACKGROUND Typically, conventional functional imaging methods involve repeated exposures to sensory stimulation. In rectal distension (RD) studies that involve multiple distensions, however, it is difficult to disambiguate the central response to RD from pathological alterations in peripheral neural responses associated with relaxation and accommodation of the rectum. METHODS This study addressed potential confounders found in previous imaging studies by collecting functional magnetic resonance imaging studies (fMRI) data during a single slow ramp-tonic distension paradigm and analysing fMRI signal changes using independent component analysis. KEY RESULTS Compared with controls, IBS participants showed increased activation of the anterior cingulate cortices, insula and ventral medial prefrontal regions suggesting heightened affective responses to painful visceral stimuli. In addition, the failure by IBS patients to down-regulate activity within ventral medial prefrontal and the posterior cingulate/precuneus regions was suggestive of reduced sensitivity to somatic changes and delayed shifts away from rest in ;default network' activity patterns. Controls showed heightened activation of the thalamus, striatal regions and dorsolateral prefrontal cortex suggesting greater arousal and salience-driven sustained attention reactions and greater modulation of affective responses to discomfort and pain. CONCLUSION&INFERENCES This work points to alterations in the central response to visceral pain and discomfort in IBS, highlighting diminished modulation and heightened internalization of affective reactions.

Depression prevalence and related factors in Iranian students.

This study designed to determine prevalence and related factors of depression in student of Arak, Iran. An analytical cross-sectional study was conducted on 304 undergraduate medical and basic students in Arak Universities, Markazi Province, Iran from May 2008 to July 2008. GHQ-28 questionnaire has been used for data gathering and analyzed by t and Chi square tests. Mean of mental health in students was 26.18 +/- 11.02 and 52.3% of students scored above the threshold of the GHQ- 28, indicating psychiatric disorder. Female sex, uninteresting of major, an uncertain future and positive family history were the most important risk factors of depression. In results didn't observe any significant relationship between age, education major and year. The prevalence of depression was higher than as compared to all population and in female exceed to male students. But there wasn't any difference between medical and non medical students. So attention to financial and occupational future graduated and under graduated students is essential.

Involvement of kappa-opioid receptors in visceral nociception in mice.

It has been shown that the behavioural responses to chemically evoked visceral nociception are increased in transgenic mice lacking the kappa-opioid receptor (KOR). The aim of the present study was to evaluate the contribution of KOR in mechanically evoked visceral pain by performing colorectal distension (CRD) and monitoring the subsequent visceromotor response (VMR) in control mice (KOR(+/+)) and in mice lacking KOR (KOR(-/-)). Pseudo-affective visceral pain responses were evoked in conscious mice using increasing (10-80 mmHg) and repeated (12 x 55 mmHg) phasic CRD paradigms. The resulting VMR was determined by monitoring the electromyographic activity of the abdominal muscle. The increasing and repeated CRD paradigms, respectively, evoked similar responses in both KOR(+/+) and KOR(-/-) mice. The selective KOR-agonists U-69593 (5 and 25 mg kg(-1), s.c.) and asimadoline (25 mg kg(-1), s.c.) significantly decreased the VMR in KOR(+/+) mice, while having no effect in KOR(-/-) mice. In contrast, the selective mu-opioid receptor agonist fentanyl significantly reduced the VMR in both types of mice and appeared more efficacious in KOR(-/-) mice. The opioid receptor antagonist naloxone (0.3-30 mg kg(-1) s.c.) did not affect the response to CRD in C57BL/6 mice at any dose tested. In conclusion, the data confirm that the KOR agonists used in this study inhibit the VMR to CRD in mice by acting via KOR receptors. In addition, the data suggest that the endogenous opioid system is not likely to modulate the VMR to mechanically evoked visceral pain in mice.

Vagal dysfunction in irritable bowel syndrome assessed by rectal distension and baroreceptor sensitivity.

Autonomic nervous system dysfunction has been implicated in the pathophysiology of irritable bowel syndrome (IBS). This study characterized the autonomic response to rectal distension in IBS using baroreceptor sensitivity (BRS), a measure of autonomic function. Rectal bag pressure, discomfort, pain, ECG, blood pressure and BRS were continuously measured before, during and after rectal distension in 98 healthy volunteers (34 +/- 12 years old, 52 females) and 39 IBS patients (39 +/- 11 years old, 35 females). In comparison with the healthy volunteers, IBS patients experienced significantly more discomfort (69 +/- 2.2% vs 56 +/- 3.6%; P < 0.05), but not pain (9 +/- 1.4% vs 6 +/- 2.4%; ns) with rectal distension despite similar distension pressures (51 +/- 1.4 vs 54 +/- 2.4 mmHg; ns) and volumes (394 +/- 10.9 vs 398 +/- 21.5 mL; ns). With rectal distension, heart rate increased in both healthy volunteers (66 +/- 1 to 71 +/- 1 bpm; P < 0.05) and IBS patients (66 +/- 2 to 74 +/- 3 bpm; P < 0.05). Systolic blood pressure also increased in both healthy volunteers (121 +/- 2 to 143 +/- 2 mmHg; P < 0.05) and patients (126 +/- 3 to 153 +/- 4 mmHg (P < 0.05) as did diastolic blood pressure, 66 +/- 2 to 80 +/- 2 mmHg (P < 0.05), compared with 68 +/- 3 to 84 +/- 3 mmHg (P < 0.05) in IBS patients. The systolic blood pressure increase observed in IBS patients was greater than that seen in healthy volunteers and remained elevated in the post distension period (139 +/- 3 mmHg vs 129 +/- 2 mmHg; P < 0.05). IBS patients had lower BRS (7.85 +/- 0.4 ms mmHg(-1)) compared with healthy volunteers (9.4 +/- 0.3; P < 0.05) at rest and throughout rectal distension. Greater systolic blood pressure response to rectal distension and associated diminished BRS suggests a compromise of the autonomic nervous system in IBS patients.

Distension-induced gastric accommodation in functional dyspepsia: effect of autonomic manipulation.

Functional dyspepsia (FD) is associated with impaired gastric accommodation and autonomic dysregulation. The aim of this study was to investigate the effects of autonomic manipulation on distension-induced gastric accommodation in subjects with and without FD, using a newly developed gastric barostat paradigm. Twelve healthy subjects (HS) and 18 subjects with FD had four barostat examinations each: no intervention, intravenous atropine (1 mg), vagal stimulation (mental relaxation with deep breathing) and acute stress stimulation (serial subtraction task). Intrabag pressure increased from 1 to 15 mmHg in 5 min (ramp phase), and was maintained at 15 mmHg for 5 min (tonic phase). Volume responses were analysed using predefined parameters. There were no significant group differences in accommodation variables between HS and subjects with FD. The FD group could be subdivided into two distinct subgroups: subgroup 1 (n = 7, 38%) with low maximum volume and accommodation rate, and subgroup 2 with normal accommodation (n = 11). In subgroup 1, but not in subgroup 2 atropine increased maximum volume and accommodation rate substantially. Neither mental stress nor mental relaxation changed any of the accommodation variables. In a subgroup of subjects with FD, impairment of distension-induced gastric accommodation can be improved by cholinergic blockade, but not by acute physiological autonomic manipulation.

A new intelligent distension system for hollow organs.

Controlled distension of hollow organs is an accepted technique for generating reproducible visceral stimuli. We have constructed a new, flexible and intelligent distension system in which discomfort, pain and autonomic responses are recorded online. These responses can be fed back into the system in a regulatory loop and be used to shape the distension paradigm. Consequently, it is possible to take all subjects to a state of equal, although subjective, level of discomfort or pain, even though pressure, tension and volume might be totally different. By using a variable airflow, this new distension system can be effectively used in all kinds of paradigms, e.g. phasic, tonic, or ramp distensions or customized combinations of them. The system can be used to control pressure, volume or tension. A refinement of the system is that it is possible to automatically change the controlled entity during a distension, e.g. from an isobaric ramp directly into an isovolumetric tonic phase. Furthermore, the distension device allows double distensions with independent distension paradigms.

CRF2 receptor activation prevents colorectal distension induced visceral pain and spinal ERK1/2 phosphorylation in rats.

BACKGROUND AND AIMS: Activation of corticotropin releasing factor 1 (CRF1) receptors is involved in stress related responses and visceral pain, while activation of CRF2 receptors dampens the endocrine and some behavioural stress responses. We hypothesised that CRF2 receptor activation may influence visceral pain induced by colorectal distension (CRD) in conscious rats, and assessed the possible sites and mechanisms of action. METHODS: Male Sprague-Dawley rats were exposed to CRDs (60 mm Hg, 10 minutes twice, with a 10 minute rest interval). Visceromotor responses (VMR) were measured by electromyography or visual observation. Spinal (L6-S1) extracellular signal regulated kinase 1/2 (ERK 1/2) activation following in vivo CRD and CRF2 receptor gene expression in the T13-S1 dorsal root ganglia (DRG) and spinal cord were determined. Inferior splanchnic afferent (ISA) activity to CRD (0.4 ml, 20 seconds) was assessed by electrophysiological recording in an in vitro ISA nerve-inferior mesenteric artery (intra-arterial)-colorectal preparation. RESULTS: In controls, VMR to the second CRD was mean 31 (SEM 4)% higher than that of the first (p<0.05). The selective CRF2 agonist, human urocortin 2 (hUcn 2, at 10 and 20 microg/kg), injected intravenous after the first distension, prevented sensitisation and reduced the second response by 8 (1)% and 30 (5)% (p<0.05) compared with the first response, respectively. RT-PCR detected CRF2 receptor gene expression in the DRG and spinal cord. CRD (60 mm Hg for 10 minutes) induced phosphorylation of ERK 1/2 in neurones of lumbosacral laminae I and IIo and the response was dampened by intravenous hUcn 2. CRD, in vitro, induced robust ISA spike activity that was dose dependently blunted by hUcn 2 (1-3 microg, intra-arterially). The CRF2 receptor antagonist, astressin2-B (200 microg/kg subcutaneously or 20 microg intra-arterially) blocked the hUcn 2 inhibitory effects in vivo and in vitro. CONCLUSIONS: Peripheral injection of hUcn 2 blunts CRD induced visceral pain, colonic afferent, and spinal L6-S1 ERK 1/2 activity through CRF2 receptor activation in rats.

Altered neuroendocrine response and gastric dysmotility in the Flinders Sensitive Line rat.

In the search for animal models that can replicate some features of functional dyspepsia (FD) patients, we turned our interest to the Flinders Sensitive Line (FSL) rat. Gastric motility disturbances prevalent in FD patients as well as urine corticosterone and plasma prolactin were measured following buspirone challenge. Flinders Resistant Line (FRL) rat was used as control. The results show that the FSL rats have a disturbed gastric motility, reflected as both an increased gastric accommodation rate and gastric volume during gastric distension as well as a delayed gastric emptying, the latter possibly as a consequence of the former. Lipid administration resulted in a significant increase in maximal gastric volume only in the FRL rats. Both the corticosterone response to buspirone and the 24-h urinary output of corticosterone were normal in FSL rats. Similar to FD patients, the FSL rat showed supersensitivity to buspirone in the increase in prolactin release. Although FSL rats show some features similar to a subset of FD patients, the increased gastric accommodation contrasts to the reduced accommodation often seen in FD patients. Further studies are warranted to determine the relevance of this rat strain as a model for FD.

A model for chronic quantitative studies of colorectal sensitivity using balloon distension in conscious mice -- effects of opioid receptor agonists.

In the current study, colorectal distension (CRD) was performed in conscious mice, in order to study visceral (colon) sensitivity. Electrodes were chronically implanted into the external oblique muscle to obtain the electromyographic (EMG) response to CRD. CRD was performed using a computerized system, which inflated the balloon with air to the desired pressures. An increasing (10-80 mmHg) and a repeated (12 x 55 mmHg) phasic paradigm with distensions lasting 10 s and with 5-min intervals were used. The EMG recordings were linearly correlated to intracolonic pressures between 10 and 80 mmHg, which are characteristic of the visceromotor response (VMR). Repeated phasic distensions at 55 mmHg resulted in a stable VMR in female mice, but an increasing VMR in male mice. Interestingly, the duration of the VMR was about 5 s, which is shorter than the actual duration of the distension. U-69593 and fentanyl (selective kappa and mu opioid receptor agonists) significantly reduced the VMR at subcutaneous doses of 0.5 and 0.05 mg x kg-1, respectively. In conclusion, a CRD model for repetitive quantitative studies of colorectal sensitivity and evaluation of pharmacological modulation of visceral sensitivity in conscious mice is presented.

Neonatal maternal separation alters stress-induced responses to viscerosomatic nociceptive stimuli in rat.

This study investigated the combined effect of neonatal maternal separation and acute psychological stress on pain responses in adult rats. Long-Evans dams and their male pups were reared under two conditions: 1) 180 min daily maternal separation (MS180) on postnatal days 2-14 or 2) no handling or separation (NH). At 2 mo of age, visceromotor responses to graded intensities of phasic colorectal distension (10-80 mmHg) at baseline as well as following acute 60 min water avoidance stress (WA) were significantly higher in MS180 rats. Both groups showed similar stress-induced visceral hyperalgesia in the presence of naloxone (20 mg/kg ip). MS180 rats had smaller stress-induced cutaneous analgesia in the tail-flick test compared with NH rats, with a residual naloxone-resistant component. MS180 rats showed an enhanced fecal pellet output following WA or exposure to a novel environment. These data suggest that early life events predispose adult Long-Evans rats to develop visceral hyperalgesia, reduced somatic analgesia, and increased colonic motility in response to an acute psychological stressor, mimicking the cardinal features of irritable bowel syndrome.

Osmotic diuretics and hemodilution in postischemic renal failure.

In the acute phase of ischemic renal failure, the severe depression of the glomerular filtration rate (GFR) is due to obstruction of the tubules by cells and cell debris rejected from the proximal tubules, a blockade which can be prevented at least partly, by treatment with osmotic diuretics. The isosthenuria, the second typical sign in ischemic acute renal failure, probably derives from the medullary ischemia that results from an intracapillary trapping of red cells. This, in turn, is suggested to be caused by oxygen-derived free radicals, which via increasing the capillary macromolecular permeability result in a massive extravasation of plasma and hence in hemoconcentration. As expected from this hypothesis, scavengers may ameliorate both the trapping and the consequent medullary ischemia. Unfortunately, however, a therapy using both osmotic diuretics and scavengers fails to improve the long-term outcome. Hemodilution would seem more promising, since it will both prevent the medullary ischemia seen in the acute phase and substantially improve the long-term outcome. At a hematocrit of 0.30, rat kidneys exposed to 45-min ischemia will show a GFR 1 month after the insult of more than 50% of the normal GFR as against 15% in untreated animals.

Oxygen radicals in postischaemic damages in the kidney.

Oxygen radicals in postischaemic damages in the kidney: M. Wolgast, A. Bayati, O. Hellberg, O. Källskog, K. Nygren and G. Ojteg, Inst. of Physiology and Medical Biophysics, University of Uppsala, Sweden; Ischemic acute renal failure is characterized by a severe depression of the glomerular filtration rate (GFR), isosthenuria and deficient potassium secretion, whereas the total renal blood flow may remain largely intact. As to these symptoms, it would seem established that the depression of GFR results from an ischaemia-induced augmented aging and hence rejection of tubular cells, which thence blocks the tubular lumen. As expected this blockade can be prevented by osmotic diuretics. The isosthenuria and the deficient potassium excretion, on the other hand, results probably from a medullary ischaemia, the latter due to the action by oxygen-derived free radicals in the sense the subsequent damage to the capillary membrane leads to a massive extravasation of plasma and consequent intracapillary trapping of red cells. In line with this idea, superoxide-dismutase (SOD) or Allopurinol may ameliorate these changes. In the recovery phase of postischaemic renal failure, the most prominent feature is the blocking of the ascending loop of Henle with Tamm/Horsfall-protein which, if not washed-out during the first week, leads to a complete degeneration of the nephron. Unfortunately, the process would seem to be unaffected by treatment with e.g. osmotic diuretics and SOD or Allopurinol.

The effect of loop diuretics on the long-term outcome of post-ischaemic acute renal failure in the rat.

The effects of continuous treatment with loop-acting diuretics on the long-term functional and histopathological outcome in kidneys subjected to 45 min of warm ischaemia were studied. One month after the primary damage the inulin clearance in the untreated kidneys was 0.44 +/- 0.05 ml min-1, improving significantly to 0.69 +/- 0.11 ml min-1 in furosemide-treated animals and to 0.75 +/- 0.09 ml min-1 in those treated with piretanide. Urine osmolality increased from 986 +/- 89 mosmol kg-1 in the untreated animals to 1479 +/- 195 mosmol kg-1 in the furosemide-treated ones. At the same time the total area of the outer medulla occupied by Tamm-Horsfall protein cylinders decreased from 7.0 +/- 1.2% in the untreated animals to 3.6 +/- 0.52% in the treated ones. It is concluded that by decreasing the number of nephrons blocked by Tamm-Horsfall cylinders an improvement in the function of ischaemically damaged kidneys can be achieved. This blockade, also called secondary damage, is of critical prognostic importance for the long-term outcome of the ischaemic renal failure. Treatment of the animals with loop diuretics decreased the occurrence of these cylinders, leading to an improvement of kidney function I month after the primary damage, this despite the fact that the primary damage seen in the early recirculation period was not treated specifically.

Red cell trapping after ischemia and long-term kidney damage. Influence of hematocrit.

The influence of the hematocrit (Hct) on the trapping of red blood cells (RBC) in the renal microvasculature and its effect on the long-term outcome following unilateral ischemia were investigated in the rat. The results showed that an increase in the duration of ischemia increased the RBC trapping, as measured by 51Cr-labeled erythrocytes, in a dose-dependent manner. At normal Hct (46%) the period of ischemia producing half-maximum RBC trapping was 45 minutes, whereas after hemodilution (Hct = 31%) or hemoconcentration (Hct = 60%) the corresponding periods were 80 and 25 minutes, respectively. Regarding the long-term outcome, 45 minutes of ischemia with a normal Hct was associated with a marked decrease in kidney weight, GFR and urine osmolarity after four weeks of recovery, which could be prevented to a large extent by hemodilution. Conversely, with hemoconcentration there was severe damage after only 25 minutes of ischemia. It is suggested that these long-term effects are attributable to RBC trapping in the microvasculature of the outer medulla, which may cause added ischemia in this area of the kidney. It is also suggested that cortical atrophy is secondary to the medullary injury, and is brought about to avoid extensive water and salt losses.

A study in the maintenance phase of ischaemic acute renal failure in the rat.

The fate of the trapped deformed erythrocytes seen in the early recirculation phase after ischaemia and the generation of long Tamm-Horsfall (TH) cylinders in the renal medulla during the first week after recirculation was studied in rats. In an in-vitro study the effects of different concentrations of TH protein on the permeability to Na+ of a semipermeable membrane were also investigated. The trapping of erythrocytes was found to be a reflow phenomenon, as there was no increase in the capillary area of the medulla in kidneys subjected to ischaemia but with no recirculation. This area increased to a maximum of 34.6 +/- 2.07% 20 min after recirculation and decreased to a normal value of 3.3 +/- 0.74% 1 day after the primary ischaemia. The area occupied by cylinders increased to a maximum of 19.2 +/- 1.4% 2 days after the primary damage and was as large as 16.7 +/- 1.47% after 1 week. It was also shown that the diffusion half-time of Na+ ions across a semipermeable membrane increased from 11.4 +/- 0.45 min to a maximum of 32.2 +/- 2.19 min with a protein concentration of 1 mg ml-1. It was concluded that the trapping of erythrocytes alone could not explain the decrease in renal function 1 week after the primary damage, but that the blockade of the tubules by the long homogeneous TH cylinders could be responsible for this decrease.