An experimental study was planned to evaluate 99m Tc-citrate, 67 Gacitrate and 99m Tc(V) dimercaptosuccinic acid (DMSA) as agents for the visualization of acute appendicitis. Appendiceal ligation was performed through a midline incision in 24 rabbits. Twenty-four hours later the animals were divided into three equal groups. The rabbits were injected through the aurical vein with 1 mCi (37 MBq) 99m Tc-citrate in group I, 0.5 mCi (18.5 MBq) 67 Ga-citrate in group II and 1 mCi (37 MBq) 99m Tc(V) DMSA in group III. After 3 h, static images of the rabbits were obtained with a gamma camera. There were positive images in seven, six and five rabbits in groups I, II and III respectively. The image quality was better in group I than in the other groups. Also, the mean uptake in group I was significantly higher than those of other two groups ( P < 0.05). There was no significant difference between groups II and III ( P > 0.05). All rabbits had appendicitis confirmed histologically. In conclusion, these results show that 99mTc-citrate is preferable to 67Ga-citrate and 99m Tc(V) DMSA for the differential diagnosis of acute abdominal inflammations such as appendicitis, because of higher concentration ratios, simple and rapid preparation, low cost, excretion mainly through the kidneys and fast blood clearance.
Few studies have pointed out the relationship between ischemia-reperfusion (IR) injury and the coagulation system. Antithrombin III (AT) has anti-inflammatory effects in IR injury. We investigated the effect of AT supplementation on renal IR injury in rats achieved by clamping of the left renal pedicle for 60 min and subsequent 24-h reperfusion after right nephrectomy. Sprague-Dawley rats were divided into three groups: sham-operated (no IR injury), ischemic controls, and an AT-treated group (250 U/kg before reperfusion). Creatinine values, tissue malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, and histopathological damage were investigated after 24 h of reperfusion. In addition, the 7-day survival rates in each group were evaluated. Creatinine and MDA levels and MPO activity were significantly elevated and histopathological damage was more severe in controls than in the sham group (P<0.05). Creatinine and MDA levels and MPO activity were significantly lower and there was less histopathological damage in the AT group than in controls. Accumulation of lipid peroxidation products and neutrophils were significantly inhibited by AT treatment. We conclude that AT may attenuate renal IR injury in rats.
One-lung flooding makes the intraoperative sonography of round pulmonary lesions possible. During the flooded phase, the flooded lung suffers a significant reduction in perfusion. After ischemia and reperfusion, neutrophil granulocytes lead to further tissue injuries. A study was made on four animals to determine whether administration of pentoxifylline — a potent inhibitor of granulocyte adhesion to the endothelium — improves lung function after one-lung flooding. Two animals were subjected to thoracotomy with extended hemodynamic monitoring. Thoracoscopy was performed on two other animals, which were extubated after the flooding liquid was drained and survived for 24°h. A bolus of 1 mg/kg of pentoxifylline was administered at the time of thoracotomy/thoracoscopy, followed by continuous infusion of pentoxifylline at a rate of 1.5 mg/kgper hour until 30°min after reventilation (thoracotomy), or until extubation, respectively. The control group consisted of animals employed in previous experiments. Except for pentoxifylline administration, they were subjected to identical experimental conditions. The control group for the thoracotomy experiment comprised 14 animals, that for the thoracoscopy experiment three animals. The experiments proved that 30°min after the draining of the flooding liquid and reventilation, all four pentoxifylline-treated animals had a higher partial arterial oxygen pressure and a lower pulmonary shunt volume compared with the control animals. In the two animals that survived, a positive effect on lung function was no longer detectable 24°h after extubation. The administration did not lead to a drop in the pulmonary arterial pressure and did not cause any hemodynamic changes other than a moderate tachycardia.
In man and experimental animals, partial and total gastrectomy and gastric vagotomies disturb extracellular mineral homeostasis, osteopenia being among the late outcomes. The sequence of events is complex and insufficiently understood. We report on the long-term effects of gastric fundectomy (FX; FX-1, n=11; sham-operated controls, n=14) sparing gastric vagal fibers at the lesser curvature in the rat, a procedure eliminating gastric acid production but preserving gastric reservoir function. After FX-1 there was a marked increase of gastrinemia [FX-1: 590 (SE 95); controls: 82 (5) pg-equiv/ml; P<0.001], serum 1,25-dihydroxyvitamin D [FX-1: 188 (17); controls: 86 (6) pg/ml; P<0.001], phosphaturia [FX-1: 32 (2); controls 23 (2) μmol/h; P<0.001] due to increased fractional phosphate clearance, elevated urinary net acid [FX-1: 21 (2); controls: 16 (1) μmol/h; P=0.03], and low urinary pH. The urinary excretion of hydroxyproline was increased [FX-1: 137 (15); controls: 99 (8) μmol/h; P=0.01], and crosslinks were also high. These changes were associated with a significant decrease of bone ash calcium, magnesium, and phosphorus. Bone histomorphometry revealed signs of high bone turnover. No signs of hyperparathyroidism were detectable. Acute stimulation of serum gastrin by gastric acid abolishing omeprazole failed to provoke extra-osseous changes, as seen in the long-term after fundectomy. It was concluded that the described type of fundectomy disturbs gastrinemia, acid-base and phosphorus metabolism, thereby initiating osteopenia. This animal model may be suitable for research into post-gastrectomy bone disease.
The localization of annexin V, a calcium binding protein, was immunochemically and immunohistologically studied in experimental rat glomerulonephritis using annexin V polyclonal antibody. Plasma and urinary annexin V levels were measured by a sandwich enzyme-linked immunosorbent assay (ELISA). Urinary annexin V level, which was correlated with urinary l-lactate dehydrogenase activity, N-acetyl-β-d-glucosaminidase activity and protein level, increased time-dependently after the injection of nephritogenic antigen (bovine glomerular basement membrane), progressively increasing to attain a peak level at 4 weeks of 51.5±11.3 ng/h. However, plasma annexin V level showed no increase during the study period. Normal kidneys showed strong staining for annexin V in distal tubules, being particularly strong in tubules of the inner stripe of the outer medulla, but could not be detected in proximal tubules. Annexin V was seen in visceral epithelial cells, Bowman’s capsule of the glomerulus, the vascular endothelium of arterioles and interlobular arteries, and vascular smooth muscle. In nephritis, the lumen of distal tubules and the luminal cell membrane were deeply stained, with leakage of annexin V being observed from tubular cells. In the present study, renal annexin V was markedly excreted into urine, and its urinary level reflected the severity of damage of renal tissue and the progression of nephritis. These changes of annexin V in the distal tubule and visceral epithelial cells may be of significance in cell injury of the kidney.
The aim of this experimental study was to investigate the effect of diclofenac sodium and ketoprofen, two non-steroidal anti-inflammatory drugs (NSAIDs) with different excretion pathways, and the role of other enteric factors during simultaneous administration of these drugs on the development of mucosal lesions of the small intestine in canines. Twenty-five animals were divided into three groups. Group I included 10 canines, 5 with diclofenac sodium (group Ia) and 5 with ketoprofen administration (group Ib). Group II included 5 animals in which a segment of ileum was surgically isolated from the rest of the small intestine. Group III included 10 animals in two subgroups of 5; a segment of ileum was surgically isolated in both subgroups; groups IIIa received diclofenac and group IIIb ketoprofen. Histological examination of the specimens taken revealed macroscopic and microscopic mucosal lesions in 5/5 animals in group Ia, whereas none of the 5 animals in group Ib had any lesions. Group II did not reveal any mucosal lesions. Three out of 5 animals (60%) administered diclofenac in group IIIa had intestinal mucosal lesions, but none of the 5 revealed lesions in the isolated loop of ileum. No lesions were observed in the isolated loop or in the rest of the intestinal mucosa in the animals in group IIIb. Our results suggest that NSAIDs produce intestinal mucosal lesions not only when administered per mouth but also after intramuscular administration. Diclofenac, unlike ketoprofen, was responsible for the development of lesions in the intestinal mucosa. The role of drugs and/or their metabolites in the intestine and certain other factors must still be determined.
Decontamination of the digestive tract with antimicrobial agents has been used for prevention and therapy of bacterial translocation. With regard to the well-described endotoxin-releasing properties of these agents, the question arises as to whether their enteral administration might result in an increased amount of intestinal endotoxins entering the circulation. Immunocompromised Wistar rats were intraduodenally challenged with live E. coli. Control animals received saline solution, decontaminated rats were treated with either tobramycin plus polymyxin B or ciprofloxacin alone through the duodenal tube. Plasma endotoxin activity and blood bacteria count were measured hourly over an observation period of 5 h. The intestinal bacterial count was determined at the end of the experiment. Gut decontamination in both groups receiving antimicrobial agents resulted in elevated plasma endotoxin levels compared with nondecontaminated controls. Maximum endotoxin levels were found to be 5-6 times higher in the ciprofloxacin group than in the control group and 2 times higher than in the tobramycin/polymyxin group. No positive blood cultures were detected. Intestinal bacterial count was similar in both treatment groups. Enterally applied antimicrobial agents bear an elevated risk of endotoxemia during the initial phase of gut decontamination. The amount of endotoxin translocating from the digestive tract to the circulation varies with the agents used. Polymyxin only partially reduced the observed endotoxin leakage from the gut.
The effects of 5-hydroxytryptamine (5-HT) and sumatriptan were investigated on isolated guinea pig gallbladder strips. While 0.1 microM-50 mM of 5-HT exhibited contractile and/or relaxant effects in quiescent preparations, the same concentrations of sumatriptan did not. On the other hand, carbachol-precontracted tissues were relaxed by the same amounts of 5-HT and sumatriptan in a concentration-dependent manner. The relaxant responses to 5-HT were not antagonized or changed by tetrodotoxin, indomethacin, capsaicin, NG-nitro-L-arginine (L-NOARG), GR55562 [(+/-)-propranolol, 3-[3-(N,N-dimethylamino)propyl 1-4-hydroxy-N-[4-(pyridin-4-yl)phenyl]benzamide , S(-)-propranolol, methysergide, ketanserin. tropisetron, GR 113808 ([1-[2-(methylsulphonylamino)ethyl -4-piperidinyl]methyl-1-methyl-1H-indole-3-carboxylate maleate salt). pargyline, and fluvoxamine. The relaxant responses to sumatriptan were antagonized by GR55562 but not by S(-)-propranolol. These results suggest that 5-HT and sumatriptan cause relaxation in carbachol-precontracted isolated guinea pig gallbladder strips by yet undefined mechanisms.
The objective of this study was to determine the effects of mechanical vibration loading on DNA and proteoglycan syntheses in cultured rabbit articular chondrocytes. Chondrocyte culture plates were placed in a vibratory apparatus and subjected to a mechanical vibratory load at various frequencies and periods in culture. Mechanical vibration was applied at a sinusoidal waveform of 1.4 g acceleration with frequencies of 200, 300, 400, 800, and 1600 Hz. H-3-Thymidine and (H2SO4)-S-35 incorporation were used to detect radiolabeled DNA and proteoglycan syntheses, respectively. A frequency of 300 Hz showed a time-dependent augmentation of DNA synthesis and gave a maximal increase at day 3 with periodic vibration (8 h per day) and at 72 h or longer with continuous vibration. It also promoted proteoglycan synthesis in long-term culture (from 3 to 15 days) by periodic vibration. However, frequencies above 400 Hz suppressed biosynthesis. These results suggest that mechanical vibration at: certain frequencies may modulate biosynthetic response of articular chondrocytes.
We determined the effects of intraperitoneally administered vitamin C on the lipid peroxidation (as thiobarbituric acid-reactive substances, TBARS) and vitamin C and E levels and reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) activity in the plasma, red blood cells (RBC), liver, and muscle of rats in relation to oxidative damage associated with diabetes induced by streptozotocin (STZ). One group was used as control and a second as diabetic. A third group received 30 mg vitamin C i.p. every other day. On day 4 after the injection of vitamin C, animals in the second and third groups were made diabetic by i.p. injection of STZ and administered vitamin C for 21 consecutive days, and we determined TBARS, vitamin E, and GSH levels and GSH-Px activities in plasma, RBC, liver, and muscle samples. Vitamin E levels in the plasma and liver were significantly higher (P<0.05) in the control group than in the diabetic group. Also, TBARS levels in the plasma, RBC, liver, and muscle samples were significantly lower (P<0.05) in controls than in the diabetic group. The TBARS levels in the RBC, liver, and muscle samples of the vitamin C group were significantly lower (P<0.05, P<0.01, and P<0.001, respectively). However, GSH-Px and GSH activities in RBC, liver, and muscle and vitamin C levels in liver were not significantly different between control and diabetic groups. Vitamin E levels in plasma (P<0.05, P<0.01) and liver (P<0.001), vitamin C levels in liver (P<0.001), and GSH (P<0.01) and GSH-Px activities in RBC (P<0.05, P<0.01) were significantly higher in the vitamin C group than both the control and diabetic groups. These results indicate that vitamin C has significant protective effects on the blood, liver, and muscle of rats against oxidative damage in diabetes.
Hyperhomocyst(e)inemia is commonly accepted as an independent atherosclerotic risk factor. In most hemodialysis patients, serum homocyst(e)ine is markedly elevated and may contribute to premature atherosclerosis in these patients. Whereas the beneficial effect of folate supplementation on serum homocyst(e)ine has been extensively studied, there are less detailed studies on the effects of cobalamin and pyridoxal phosphate alone, or in combination with folate. We examined the effect of a four-week course of intravenous treatment with folate (1.1 mg), cobalamin (1.0 mg), and pyridoxal phosphate (5.0 mg), administered once (group 1), twice (group 2) or thrice (group 3) weekly in 33 hemodialysis patients divided in three groups of 11 patients. All patients were followed for a further four weeks after treatment was stopped. Serum homocyst(e)ine, cobalamin, folate and pyridoxal phosphate, as well as the metabolites of homocyst(e)ine, methylmalonate, 2-methylcitrate and cystathionine, were determined before, during and after treatment. Baseline serum homocyst(e)ine correlated significantly with serum folate (P=0.0149), cobalamin (P=0.0047) and pyridoxal phosphate (P=0.0408). Correlations independent from the other metabolites or vitamins were found for methylmalonate (P=0.003) and folate (P=0.029). All regimens increased serum cobalamin significantly (in group 1 from 444 +/- 215 to 17,303 +/- 11,989 pg/ml, P<0.01; in group 2 from 542 +/- 633 to 44,896 +/- 15,772 pg/ml, P<0.001; in group 3 from 548 +/- 394 to 77,961 +/- 31,546 pg/ml, P<0.001), but did not increase any of the other vitamin levels. Serum homocyst(e)ine was lowered significantly by 39.8% +/- 31.9% (P<0.05) with two and by 30.1% +/- 26.9% (P<0.05) with three vitamin dosages weekly, but not with one dosage weekly. Since methylmalonate is known to be a sensitive marker of cobalamin deficiency, the data support an important influence of cobalamin levels on baseline homocyst(e)ine levels. Increasing cobalamin levels and additional treatment with folate and pyridoxal phosphate 156 may decrease serum homocyst(e)ine in the same way as high doses of folate alone.
We evaluate the chondrotoxic effects of some nonsteroidal anti-inflammatory drugs (NSAIDs) on articular cartilage in an experimental model of osteoarthritis (OA). Each of 40 Sprague-Dawley rats weighing 0.250 kg and 12 weeks old received weekly injections of sodium iodoacetate (1 mg/0.1 ml NaCl) in the right knees for 8 weeks to induce an experimental model of OA. The left knees served as controls. Four groups were formed of ten rats each. The control group received no medicine. In the other three groups, tiaprofenic acid, diclofenac, and indomethacin were given orally for 12 weeks. At the end of the 20th week, the complete groups were sacrificed and histologic evaluation performed. In the right knees of the control group, specific morphologic changes for OA were observed. Of the three NSAIDs tested, indomethacin was found to have deleterious effects on articular cartilage of both left and right knees. Diclofenac caused a statistically significant increase in the severity of most of the osteoarthritic parameters that were examined in the right knees, whereas tiaprofenic acid was observed to have some beneficial influences on the articular cartilage of right knees. Both diclofenac and tiaprofenic acid displayed the same deleterious effects on articular cartilage of left knees. We conclude that, in the prescription of NSAIDs for OA, it would be appropriate to choose a drug with a protective effect on chondrocytes and articular cartilage.
In an effort. to develop a reproducible model of liver cirrhosis and esophageal varices, we administered phenobarbital (PhB) and carbon tetrachloride (CCl4) in 32 rats that had previously undergone complete devascularization of the left renal vein (DLRV). The operation was conducted to enhance the development of cephalad collaterals mainly responsible for the induction of esophageal varices. Thirty-two rats underwent sham operation and PhB and CCl4 administration, and 24 only sham-operated rats comprised the control group. After the induction of liver cirrhosis, histopathologic examination and morphometric analysis of the lower esophagus were performed to study the submucosal veins. We separately studied number of vessels in the submucosa, mean vessel area, percentage of submucosa occupied by vessels, and area of the single most dilated vein. All variables except the number of vessels were significantly higher in cirrhotic rats that had undergone DLRV (P < 0.001). We conclude that: induction of liver cirrhosis in rats that previously undergo complete DLRV could present a reproducible and reliable model for the induction of liver cirrhosis and esophageal varices.
In isolated working rat hearts, a rapid up- or downward change in perfusate Ca2+ concentration by the factors 2, 4, or 8 in the range between 1.25 and 10 mM resulted within 1 min in the well-known change of left ventricular contractility as evaluated by maximum left ventricular pressure change velocity (LVdP/dtmax) and left ventricular end-diastolic pressure (LVEDP). However, within about 10 min thereafter, contractility showed an adaptive behaviour opposite to the initial change, with t 1/2 values for LVdP/dtmax between 1.45 and 2.8 min. The adaptive LVdP/dtmax reactions amounted to 10–35% of the initial change. With an abrupt fall from 10 mM to 1.25 mM Ca2+ (not tolerated by all hearts), LVdP/dtmax decreased initially by 4.260 mmHg/s (LVEDP +9.7 mmHg) and increased thereafter by 524 mmHg/s (LVEDP −6.8 mmHg). The adaptive inotropic behaviour cannot be related to changes in heart rate or coronary flow and is not affected by thapsigargin (1 µM) or the amiloride derivative benzamil (10 µM). This suggests that sarcoplasmatic Ca2+-ATPase and sarcolemmal Na+-Ca2+ exchange do not play a decisive role in this adaptive behaviour. In conclusion, an intrinsic regulatory mechanism of the myocardium attenuates the inotropic effect of acute changes in Ca2+ concentration. This phenomenon might protect the heart against Ca2+ overload after an acute rise in catecholamine concentration.
Hypothermia of the ischemic organ at 4°C protects hepatic microcirculation from ischemia-reperfusion (IR) injury. The effect of hypothermia during ischemia was investigated in animal models using liver transplantation and storage of the harvested organ in cold preservation solutions. No investigation of the isolated influence of hypothermia at 4°C of the ischemic organ on hepatic IR injury exists, due to the lack of an appropriate animal model. Therefore, the aim of our present study was to develop such a model using intravital video fluorescence microscopy (IVM). In C57BL/6 mice, a reversible isolated ischemia of the left liver lobe was induced for 90 min, followed by 240 min of reperfusion. The temperature of the ischemic organ was adjusted to either 4°C or 37°C by superfusion with 0.9% NaCl. Sham-operated animals without IR served as controls. The hepatic microcirculation was analyzed using IVM at 30 min and 240 min after reperfusion by quantifying sinusoidal perfusion and leukocyte-endothelial cell interaction in postsinusoidal venules. At the end of the experiment, blood and tissue samples were taken for measurement of liver enzyme activities and light and electron microscopy. Mean arterial pressure and body temperature were kept constant throughout the experiment, while the temperature of the ischemic liver lobe was adjusted to predefined levels. After normothermic ischemia, hepatic microvascular perfusion was significantly impaired compared with sham-operated animals. Perfusion failure was significantly reduced in hypothermic livers and did not differ from livers of the sham-group. Liver enzyme activities in the normothermic group were significantly higher than in the sham and hypothermic groups. Light and electron microscopy revealed severe histological alterations at 37°C ischemia, whereas at 4°C ischemia only minimal lesions were encountered. Our novel model allows for isolated adjustment of ischemic liver lobe temperature without changing body temperature and systemic macrohemodynamic parameters. Hypothermia at 4°C largely attenuates postischemic microvascular perfusion injury of the liver.
An increase in oxidative stress may contribute to the development of oxidative protein damage in streptozotocin diabetic rats. In the present study, the influence of alpha-lipoic acid supplementation on plasma protein carbonyl, plasma thiol, and plasma lipid hydroperoxide levels was examined in order to characterize the relationship between the oxidative stress and the oxidative protein damage. Rats were randomly divided into three groups of equal body weight. Chronic hyperglycemia was induced by intravenous streptozotocin injection in both the group of male Wistar rats to be supplemented with alpha-lipoic acid and the group that was not to receive alpha-lipoic acid. Nondiabetic rats formed the control group and received a saline injection. In streptozotocin diabetic rats with and without alpha-lipoic acid supplementation, plasma carbonyl levels were significantly increased, while plasma thiol levels were significantly decreased compared with those of the control group. Plasma lipid hydroperoxide levels were significantly increased in diabetic rats without alpha-lipoic acid supplementation compared with those of the controls, but the lipid hydroperoxide levels in the alpha-lipoic acid supplemented group were no different from those of the controls. In streptozotocin-diabetic rats, oxidative stress was significantly decreased in the alpha-lipoic acid-supplemented group. The results of this study suggest that alpha-lipoic acid, by decreasing oxidative stress, may be effective in preventing oxidative protein damage, which may contribute to the development of diabetic complications.
Impulse Oscillometry is a new, noninvasive method to measure respiratory impedance, i.e. airway resistance and reactance at different oscillation frequencies. These parameters are potentially useful for the monitoring of respiratory mechanics in the critically ill patent with respiratory dysfunction. The endotracheal tube, used to mechanically ventilate these patients, however, represents an additional nonlinear impedance that introduces artifacts into the measurements. The objective of this work was therefore to investigate the effects of clinically available endotracheal tubes on resistance and reactance of an in vitro analogue of the respiratory system. Additionally, the effects of decreasing the compressible gas volume in this experimental model, as a simulation of decreased lung capacity and compliance, was investigated. Impulse oscillometric measurements of the test analogue gave highly reproducible results with and without an endotracheal tube. The tubes had significant influence on the measurement of the test object at all frequencies investigated. Changes of low frequent reactance were negligible - at least if repetitive measurements of the same system are performed - for realistic measurement of airway resistance, a correction of the tube impedance or measurement of the pressure distal of the tube is required. Resistance increased and low frequent reactance decreased significantly with decreasing gas volume. These changes were of magnitudes higher than the variations due to the introduction of the endotracheal tubes. Our results suggest that changes of respiratory reactance measured with impulse oscillometry may be used as a monitoring parameter in intubated patients.
The neuroprotective effect of trimetazidine (TMZ) was tested prospectively in a rabbit spinal cord ischemia model. Ischemia was induced by clamping the aorta just distal to the left renal artery and proximal aortic bifurcation for 20 min. Twenty-five male New Zealand white rabbits were randomized as follows: TMZ group (n=100) receiving 3 mg/kg trimetazidine intravenously before the occlusion of the aorta; control group undergoing occlusion but receiving no pharmacologic intervention (n=10); sham-operation group (n=5) subjected to operative dissections without aortic occlusion. Physiological parameters and somatosensory evoked potentials (SEP) were monitored in animals before the ischemia, during the ischemia and in the 1st, 15th and 60th min of reperfusion. Neurologic status was assessed 24 and 48 h after the operation. The spinal cord, abdominal aorta, and its branches were processed for histopathologic examinations 48 h after the operation. At the end of the ischemic period, the average N1-P1 amplitude was reduced to 22% of the baseline in all ischemic animals. This was followed by a gradual return to 90+/-2% of the initial amplitude in the TMZ group and 81+/-2% in the control group (P<0.05) after 60 min of reperfusion. The average motor function score was significantly higher in the TMZ group than the control group (3.7+/-0.5 vs 3.1+/-0.6 at 24 and 3.5+/-0.7 vs 2.9+/-0.6 at 48 h; P<0.05). Histologic observations were clearly correlated with the neurologic findings. The results suggest that trimetazidine reduces spinal cord injury during thoracoabdominal aortic operations and may have therapeutic utility during high risk operations.
Mast and parietal cells were concomitantly demonstrated in biopsies from corpus mucosa of patients with various forms of chronic gastritis. The ratio of mast/parietal cells and the ratio of maximal and basal acid output were negatively correlated.
