Role of capsaicin-sensitive nerves in gastric and hepatic injury induced by cold-restraint stress

The role of capsaicin-sensitive afferent fibers on cold-restraint stress-induced gastric and hepatic injury was examined at the macroscopic and ultrastructural levels. Wistar albino rats were treated with capsaicin either locally (intragastric, perivagal, and periceliac) or systemically (neonatal, intraperitoneal). Perineural and neonatal treatment with capsaicin was used to denervate afferent fibers, while intragastric capsaicin treatment would have activated mucosal afferent fibers just before the stress exposure. Capsaicin decreased significantly the formation of macroscopic gastric lesions caused by stress in all treatment groups. At the electron microscopic level, however, denervation of vagal afferent fibers with capsaicin was most effective in prevention of cellular injury in gastric mucosa. In the liver, systemic denervation of afferent fibers completely inhibited stress-induced cellular damage, while denervation of afferent fibers in vagus and splanchnic nerve was partially effective. Central neural pathways sensitive to capsaicin may mediate formation of both gastric and hepatic injury resulting from stress.

The effect of endoscopic sinus surgery on mucociliary activity and healing of maxillary sinus mucosa

The aim of this study was to determine histologic findings in the maxilaarysinus mucosa by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and ciliary activity within the nasal cavity by measuring the speed of mucociliary transport and after endoscopic sinus surgery (ESS). Thirty patients were enrolled. Thirty-eight antral mucosae of 24 24 patients were investigated according to ultrastructural changes and 6 patients were accepted as controls. At the 12th week, 12 antral nasal mucosae specimens of 8 patients were evaluated. All the specimens were taken from the medial rear wall of the antrum. The specimens were observed under a SEM and TEM. The mucociliary activity was measured within the nasal cavity by a saccharin test in all patients before the operation and after 12 weeks. Twenty people served as controls. In the specimens of the preoperative mucosa, the ciliated epithelium was heavily deciliated, interdigitation of the cell was loosened. In the samples taken 12 weeks after the operation, the ciliated cells were irregularly seen, the number of goblet cells was about the same as in the preoperative group and in the control, the number of the gland openings was higher than in the preoperative group and in the control. Also the interdigitation of the cells was enhanced. The histological and morphological features of the mucosa had improved. The period of the preoperative saccharin test was 12.15 minutes, whereas the period of the postoperative test was 9.08 minutes. The improvement was significant but both results were also significantly longer compared to the controls. These observations suggest that the histological, morphological and mucocilliary activity of the mucosa have not yet improved completely, it takes more than 12 weeks to recover, and the patients should be closely monitored in the postoperative months.

Comparative evaluation of antibacterial effects of Nd:YAG laser irradiation in root canals and dentinal tubules

The antibacterial effects of the Nd:YAG laser on contaminated root canals and dentinal tubules were observed as the aim of this study. The samples were inoculated with Streptococcus sanguis (NCTC 7853) and Prevotella intermedia (NCTC 93336), and the effects of Nd:YAG laser were tested on these teeth. The specimens were lased with 1.8 W and 2.4 W Nd:YAG laser for 30 s, and the presence of bacteria in tubules was observed under light microscopy. The 1.8 W laser sterilized the tubules in 86.3% of sections inoculated with S. sanguis, whereas 2.4 W laser sterilized in 98.5% of the sections. Both laser powers sterilized all samples inoculated with P. intermedia. The scanning electron microscopic observations supported the light microscopic findings.

In vitro study of the penetration of Streptococcus sanguis and Prevotella intermedia strains into human dentinal tubules

The persistent presence of bacteria in the root canal system often leads to the failure of treatment. The purpose of this study was to determine in vitro penetration of Streptococcus sanguis and Prevotella intermedia into dentinal tubules. Samples obtained from human teeth were inoculated with a strain of S. sanguis (NCTC 7853) and P. intermedia (NCTC 93336) for 20 days. Bacterial penetration into tubules was investigated at scanning electron microscopy and light microscopic level. The results showed that S. sanguis could penetrate into dentinal tubules 382.3 microns, whereas P. intermedia could penetrate 25.9 microns. It was observed that P. intermedia had not penetrated into all dentinal tubules. If penetration occurred the depth was quite limited.

Congenital microvillus atrophy in a 4-month-old girl

Congenital microvillus atrophy is a severe generalized enteropathy with ultrastructural abnormalities of the intestinal brush border. It is a rather new clinicopathological entity which needs to be differentiated from other enteropathies within the spectrum of intractable diarrhea of infancy. The presented case was a four-month-old girl with a chronic, intractable diarrhea, beginning at birth. The diagnosis was established only after the electron microscopic examination of small intestinal mucosa which revealed the characteristic features of the disease. Congenital microvillus atrophy is a rare autosomal recessively inherited disorder and bowel transplantation becomes a realistic option of treatment. Therefore, it should be specifically considered in the differential diagnosis of chronic intractable diarrhea of infancy.

Polymers for sustained release formulations of dipyridamole-alginate microspheres and tabletted microspheres

The preparation of dipyridamole (DIP) alginate (alg) microspheres by different methods or the incorporation of tragacanth (trgh), pectin or Eudragit L-100 55 (Eud) in alg microsphere formulations did not provide a prolonged release of DIP at pH 1.2. Tabletted microsphere formulations containing alg, trgh, pectin, sodium carboxymethyl cellulose (CMC), sodium starch glycolate (SSG), carrageenan (carrg) or Eud as diluents in different ratios, produced tablets with good physical properties which did prolong DIP release. The type, viscosity and the ratio of the diluent polymer, microsphere size and the compression pressure were found to be important factors to produce tablets with desired properties. No advantage of the tablets containing alg microspheres and granulated diluents was observed over the tablets containing powdered diluents.

Preparation and tabletting of dipyridamole alginate-Eudragit microspheres

Dipyridamole alginate-Eudragit microspheres were prepared by the emulsification technique of Monshipouri and Price. After modification of the formulation and process variables of this method it was possible to obtain spherical and discrete particles. Microspheres were free flowing and the release of drug was slow compared to granules and powder. To further control the release rate of the drug, tablets of microspheres were prepared, adding 20% HPMC 90 SH 4000 and 90 SH 100,000 and compressing at 98 mPa or 147 mPa. Increasing the amount of additive and the compression pressure decreased the release rate of drug.

Histological changes following epidural injection of midazolam in the neonatal rabbit

Midazolam can produce antinociceptive effects when used via intrathecal or epidural routes. Neurotoxicity studies are scanty especially for neonates. The aim of this study was to carry out electron microscopic (EM) examinations in the neonatal rabbit to determine the histological effects of epidural midazolam on spinal cord. Twenty white New Zealand neonatal rabbits were randomly assigned to three groups receiving single dose of 0.9% saline (Group I; Control, n = 4), 0.9% saline titrated to pH = 3.9 by addition of hydrochloric acid (Group II; n = 6), midazolam 250 micrograms.kg-1 (Group III; n = 12) epidurally. Half of each group were sacrificed on the second day and the remainder on the seventh day and spinal cord sections were evaluated by EM. Control group displayed normal histology on grids. Group II and II showed a variable degree of neurotoxic effects such as degeneration of vacuoles, cytoplasm and neurofilaments, disruption of myelin sheaths, lysis of cell membranes, perivascular oedema, pyknosis of nuclei. The toxic effects of acidic saline and midazolam are similar, in view of these results the epidural use of acidic midazolam (commercially available preparations) in neonates should be avoided.

Scanning electron microscopic examination of different cleaners: surface contaminant removal from dentures

Dentures were examined by scanning electron microscopy to evaluate removal of surface contaminants. Five complete dentures were obtained during patient appointments. The palatal surface of each denture was divided into eight pieces (1 cm2) then each sample cleaned with Corega, Dentipur, Fittydent, sodium hypochloride, Savlon, Ipanol, brushing methods and one sample was also kept as a control. They were prepared for SEM examination and photographed at x500. One photograph of each sample was evaluated in random order by three judges for a total of 120 observations. Photographs were compared with one of a clean denture sample. Statistical analysis of the results showed that soaking dentures in sodium hypochloride and Savlon removed significantly more contaminants than any of the other methods used in this study.

Intermittent aortic cross-clamping and cold crystalloid cardioplegia for low-risk coronary patients

BACKGROUND

Blood cardioplegic strategies have been shown to increase myocardial oxygen uptake, replenish depleted energy stores, and improve myocardial function and survival in the high-risk subset of patients. However, the superiority of these techniques over intermittent aortic cross-clamping and crystalloid cardioplegia in low-risk patients is still controversial.

METHODS

This study consisted of two parts. In the first part, we assessed the results of a recent cohort of 399 consecutive low-risk patients undergoing their first coronary artery bypass grafting between 1993 and 1995 using cold crystalloid cardioplegia (n = 128) and intermittent aortic cross-clamping (n = 271). In the second part of the study, 40 consecutive low-risk patients undergoing elective first time coronary artery bypass grafting were randomly divided into two equal groups. One group received cold crystalloid cardioplegia and the other group had myocardial management with intermittent aortic cross-clamping. The two groups were compared with respect to hemodynamic, biochemical and ultrastructural changes.

RESULTS

The overall mortality rate, the perioperative myocardial in the need for intraaortic balloon pumps, and the need for inotropic agents were 0.25%, 1.5%, 1%, and 5.8%, respectively. No significant differences were observed between the groups with respect to these clinically defined end points.

CONCLUSIONS

Both intermittent aortic cross-clamping and cold crystalloid cardioplegia techniques may be used safely in low-risk patients undergoing first-time coronary artery bypass grafting.

Cold-restraint- and TRH-induced ulcer models demonstrate different biochemical and morphological manifestations in gastric and hepatic tissues in rats. Role of calcitonin

In the present study, two ulcer models--central thyrotropin-releasing hormone (TRH) injection and cold-restraint stress (CRS) application--were compared. Animals were treated either with salmon calcitonin (sCT) or saline intracerebroventricularly (ICV) before CRS exposure or ICV TRH injection. In both models, besides ultrastructural properties, ulcer indexes and lipid peroxidation (LP) and glutathione (GSH) levels of liver and stomach were determined. While TRH treatment did not affect GSH and LP levels of the stomach and led to a slight decrease in hepatic GSH levels, CRS induced a marked reduction in gastric and hepatic GSH and an increase in LP levels of both tissues. sCT pretreatment prevented the reduction of gastric and hepatic GSH levels and morphological damage of both tissues in the CRS group. However, the same treatment did not prevent the TRH-induced reduction of hepatic GSH levels and, interestingly, it worsened the ultrastructural disturbances in the liver. Although sCT prevented macroscopic ulcer formation in both models, it did not totally reverse the microscopic effects of TRH.

The regeneration of the middle ear mucosa of the rat

The purpose of the study was to investigate the regeneration of middle ear mucosa following surgical removal and to observe the effects of Silastic sheetings on regeneration. Two weeks after the operation the middle ear cavity was covered by moderately differentiated epithelium in the animals which had only the mucosa removed. In animals with inserted Silastic sheeting, infection slowed down the regeneration process. During the 2 months of postoperative observation, the surface of the cavity appeared to be rough, and there was intensive fibrin deposition over the mucosa. It is concluded that normal middle ear mucosa regenerates rapidly after surgical removal. On the other hand and in contrast to the purpose of its usage, Silastic sheeting slows down the process and causes fibrosis.

A murine model of adenomyosis: the effects of hyperprolactinemia induced by fluoxetine hydrochloride, a selective serotonin reuptake inhibitor, on adenomyosis induction in Wistar albino rats

OBJECTIVE

The aim of this study was to investigate whether fluoxetine given to castrated and noncastrated rats caused hyperprolactinemia and its effects with respect to adenomyosis.

DESIGN

Fluoxetine, a serotonin reuptake inhibitor, was given to Wistar Albino rats for 98 days to produce hyperprolactinemia. The drug was given to two groups consisting of castrated and noncastrated rats and compared to two groups of castrated and noncastrated controls. Prolactin levels were measured and the uteri of the rats were removed for histopathological analysis at the end of 98 days.

SETTING

Marmara University School of Medicine, Department of Histology and Embryology, Zeynep Kamil Women and Children's Hospital.

MAIN OUTCOME MEASURES

Serum prolactin levels, uterine histopathology.

RESULTS

The prolactin levels of castrated and noncastrated groups treated with fluoxetine were statistically significantly higher when compared to their respective control groups. Histological studies revealed 11 cases of adenomyosis, all within the noncastrated group receiving fluoxetine.

CONCLUSION

It was suggested that high serum prolactin levels cause degeneration of myometrial cells in the presence of ovarian steroids that results in a myometrial invasion by endometrial stroma. This invasion eventually progresses to adenomyosis.

The effect of endothelin-1 on vena jugularis thrombus model in rabbits

Endothelins (ET) are the most important vasoconstrictors known, and administration results in contraction of vascular strips in man and experimental animals in vitro. We examined the effects of ET-1 on thrombus formation in rabbits. We used vasoconstrictor and thrombus forming agents and we selected an animal model, the vena jugularis thrombus model. In addition, intravascular endothelium was examined ultrastructurally. The ET-1 level is known to be high in patients with hypertension; if these patients also have atherosclerosis, then intravascular thrombus formation may increase. In the vena jugularis thrombus model, thromboplastin and ET-1 act synergistically to increase intravascular thrombus formation. On injection of ET-1 dose dependent vasoconstriction was shown in the vessel wall. Although similar maximal contraction is achieved, a decrease in vessel diameter is associated with increased potency of ET-1 and thromboplastin. The results suggest that ET-1 may regulate vascular tone through constriction of vessels.

Morphological changes in carotid arteries of rabbits induced by defibrotide infusion

Defibrotide is an antithrombotic and profibrinolytic drug which modulates endothelial function. The drug increases prostacyclin and tissue plasminogen activator while it decreases plasminogen activator inhibitor synthesis by endothelial cells. In this study, in vivo effects of defibrotide on the morphology of endothelial cells and vessel wall of the healthy rabbits were investigated by light and electron microscopy. The examination of the carotid arteries of healthy rabbits after infusion of saline or defibrotide (10 mg/kg/hr) in saline solution for three hours revealed that the drug had induced dramatic morphological changes in all the test animals while no change was observed in control group. The changes observed after defibrotide administration, such as the decrease in hill and valley-like appearance of endothelial surface, and thinning of the intimal layer provides evidence for the vasorelaxant effect of the drug, while the decrease in the number of blood cells adhering to the endothelial surface confirms the antithrombotic effect of defibrotide. Finally the decrease in the number of crater-like structures may be due to the cytoprotective effect of the drug.

Root resorption and pulpal changes due to intrusive force

Intrusion has been regarded as a controversial topic in the literature. It is apparent from many studies that excessive forces applied in orthodontic treatment might lead to undesirable results such as circulatory disturbances, pulp degeneration, calcification and even necrosis. This study was performed to observe the reaction of pulp and roots following tooth intrusion. Material consisted of four first premolar teeth of two adult patients. One premolar of each patient was intruded orthodontically and the other premolars were taken as controls. The palatal roots of the experimental teeth were cut and examined in scanning electron microscope (SEM) and the pulps of the teeth were examined in transmission electron microscope (TEM). At SEM examination, root surfaces of intruded teeth showed resorption cavities of different diameters and depths. At TEM examination, vascular degeneration was the main change in the pulps of experimental teeth.

A comparison of two different rapid palatal expansion techniques from the point of root resorption

The aim of this investigation is to compare Haas and Cast Cap Splint devices from the point of root resorption. The material comprised thirty-eight upper and twelve lower premolar teeth derived from nineteen patients who required RME and subsequent removal of the first premolars as part of their full banded orthodontic treatment. Root resorption and repair areas were observed on the buccal surfaces of premolars. Repair tissue was cellular cementum in both groups. There was no significant difference between these two techniques from the point of root resorption amount.

The effect of nordihydroguaiaretic acid on leukotriene C4 and prostaglandin E2 production following different reperfusion periods in rat brain after forebrain ischemia correlated with morphological changes

Leukotriene C4 (LTC4) and prostaglandin E2 (PGE2) are the 5-lipoxygenase and cyclooxygenase metabolites of arachidonic acid (AA). They constrict blood vessels and enhance vascular permeability inducing vasogenic edema that may hurt the ischemic penumbra after cerebral ischemia and reperfusion. Nordihydroguaiaretic acid (NDGA) is known as the most potent inhibitor of 5-lipoxygenase in different tissues. Furthermore, it has considerable inhibitory activity against cyclooxygenase. In this study, after developing a global ischemic model in the rat, the levels of LTC4 and PGE2 in the forebrain were measured, following different reperfusion periods after 10 min ischemia including 8 rats for each reperfused group. Sham operations were performed for each corresponding control group (n = 8). AA metabolites were then correlated with neuropathological findings. In the combined reperfused groups both metabolites increased significantly when compared with 10 min, ischemic group (P < 0.05). In the 8 min reperfused group, PGE2 and LTC4 increased significantly compared with each corresponding control group (P < 0.005). These mediators also increased to high levels compared with the 4 min reperfused group (P < 0.05, P < 0.005). PGE2 and LTC4 were reduced significantly at the 15th and 60th min of reperfusion compared with the 8 min reperfused group (P < 0.05, P < 0.005). NDGA (0.1 mg/kg) reduced both metabolites in the 8 min reperfused group significantly (P < 0.05). Brain cortex specimens were taken for light and electromicroscopical investigations. No significant differences were noted between the structural changes in the 4, 8 and 15 min of reperfusion and NDGA administered groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin E2 and leukotriene C4 levels following different reperfusion periods in rat brain correlated with morphological changes

Prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) are the metabolites of arachidonic acid (AA) that increase in forebrain following global ischemia and reperfusion. These mediators are highly potent vasoconstrictors of cerebral arteries leading to enhanced vascular permeability that induces the formation of vasogenic edema. In this study, after developing an experimental animal model simulating the concept of ischemic penumbra in the rat, the levels of PGE2 and LTC4 produced in the forebrain were measured and the effects of these mediators in short duration and prolonged reperfusion were investigated and then correlated with neuropathological findings. We found statistically significant reduction both in PGE2 and LTC4-like activities after just 10 min ischemia (p less than 0.05, p less than 0.05). PGE2-like activity significantly increased in the 4th and 60th min of reperfusion (p less than 0.05, p less than 0.05). In the 15th min of reperfusion, PGE2 was found to be significantly reduced (p less than 0.005) that may be due to the formation of free oxygen radicals by activation of PG hydroperoxidase reaction that inhibits PGE2 production in the cyclooxygenase pathway. LTs were not significantly increased in any reperfused group. Inhibition of the lipoxygenase pathway of AA metabolism may occur as a result of 15-HPETE (15-hydroperoxyeicosatetraenoic acid) production. Pathologically, edema and degeneration of brain tissue were seen beginning from the 4th min of reperfusion that reached a peak in the 60th min of reperfusion which is in accordance with biochemical changes in the damaged tissue.(ABSTRACT TRUNCATED AT 250 WORDS)