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ThesisItem Open Access Processed aortic allografts for oesophagoplasty in dogs(Department of Surgery, College of Veterinary and Animal Sciences, Mannuthy, 1998) Balagopalan, T P; KAU; Muraleedharan Nayar, K NThe study was conducted with the objectives of a. Preparation, preservation and evaluation of chrome/ glutaraldehyde cross linked aortic tissue of dogs and to compare the relative acceptability and efficacy of them for cervical oesophagoplasty in dogs, and b. Evaluation of modified pharyngostomy feeding method and its effect on healing at cervical oesophagoplasty site in dogs. The experiment was conducted in thirty, apparently healthy, adult, nondescript dogs of either sex weighing 9-13 kg. The animals were randomly divided into three groups viz.,, group I, II and III. Group II and III were subdivided into two subgroups each, namely IIA, IIB and iilA, IIIB. Group I and the subgroups consisted of six animals each. Animals of group I were subjected to sham operation. Cervical oesophagoplasty using chrome processed aortic allograft and glutaraldehyde processed aortic allograft were performed in animals of group II and III respectively. Pharyngostomy tube feeding was instituted in three animals of group I and all animals of subgroups IIB and IIIB. Tissue samples of thoracic aorta harvested from dogs, processed and crosslinked with chromic sulfate and glutaraldehyde were used as graft materials. Chrome processed aorta showed better biomechanical qualities except for tensile strength than glutaraldehyde processed aorta. The grafts had fairly good handling qualities and shelf life. All the animals were premedicated with triflupromazine hydrochloride and anaesthetized using thiopentone sodium to effect. Wound, oval in shape measuring 3-4 cm long and l/3rd of the circumference of the oesophagus was created in all experimental animals. Oesophagoplasty was performed by fixing the graft material over the defect using 5-0 braided silk thread and continuous lock stitch sutures. Left side' pharyngostomy was performed in 15 dogs. Suitably designed siliconised catheter made up of modified polyvinyl chloride with an attached X-ray opaque line was used as pharyngostomy tube. The tube was kept in situ for a period of 15 days postoperatively for administration of fluid diet. The animals were kept under observation for varying periods of 15, 30 and 60 days postoperatively. The animals of subgroups IIB and IIIB became alert and active earlier than that of IIA and IIIA. At the cervical region, the operated site showed mild inflammatory reaction by 1-2 days postoperatively in all animals. The sutures were removed after normal healing by 7-8th day in all animals except one each in subgroup IIA and IIIB, where it was removed on the 10th day. Mild bleeding while performing pharyngostomy (one dog) and moderate pain and slight swelling around the pharyngostomy tube entrance site (3 dogs) were observed in subgroup IIB. One animal in subgroup IIIB showed severe inflammatory oedema around the tube entrance site. Tolerance of pharyngostomy tube was excellent in 13 dogs. The pharyngostomy wound healed completely by 14-15th day after removal of the tube in all the dogs. All the animals started feeding on liquid food by seventh day postoperatively in subgroups IIA and IIIA following hyperalimentation via intravenous route and by 15th day in subgroups IIB and IIIB following hyperalimentation via pharyngostomy tube. They maintained normal apetite and feeding habits thereafter during the period of observation. Mild swelling at the operated site while swallowing (3 dogs) and vomiting (one dog) were noticed among the animals of subgroup IIA and IIIA. Initial tube obstruction during first feeding (6 dogs), vomiting after first feeding (2 dogs) and mild diarrhoea (one dog) were observed among animals of subgroup IIB and IIIB.ThesisItem Open Access General anasthesia in dogs with Tiletamine-Zolazepam(Department of Surgery, College of Veterinary and Animal Science, Mannuthy, 1995) Rajankutty, K; KAU; Muraleedharan, Nair K NThe present study was undertaken to findout the efficacy of tiletamine – zolazepam alone and with xylazine premedication for anaesthesia in dogs and to evaluate the systemic changes consequent on the administration of these drugs. The experimental study was conducted on 36 adult non- descript dogs of either sex. The animals were randomly divided into two groups, (Group I and II ) consisting of 18 animals each. Each group was further divided into three subgroups, viz A, B and C, consisting of six animals each. Atopine sulphate (0.04 mg/kg bodyweight) was administered IM 15 minutes prior to the administration of the experimental drugs in all the dogs. Tiletamine – zolazepam (T-Z) combination was administered IM at the rate of 5mg, 10 mg and 15 mg/kg bodyweight in the subgroups IA, IB and IC respectively. Xylazine at the rate of 0.5 mg/kg bodyweight and 15 later, T-Z combination at the rate of 5 mg, 10 mg and 15mg/kg bodyweight were administered IM in the subgroups IIA , IIB and IIC respectively. The induction time was 6.17 + 1.01 min, 4.33 + 0.21 min and 4.33 + 0.49 min in subgroups IA, IB and IC respectively, and 3.33 + 0.62 min, 3.17 + 0.48 min and 2.83 + 0.54 min in subgroups IIA, IIB and IIC respectively. Increase in the dose of T-Z reduced the induction time and premedication with xylazine further reduced the induction time and induction was smooth. The onset of effect of tiletamine – zolazepm was characterized by the winking of eyes, yawning, licking and protrusion of tongue. The eyes remained open and pupils were slightly dilated. The palpebral and pedal reflexes and swallowing movements were not abolished. Salivation was scanty in both the groups. In the animals of group II the eyes were partially closed and palpebral and pedal reflexes were abolished but the swallowing movements were not. Protrusion of tongue, though present, was not to the extent that was observed in the animals of group I. Rhythmic side to side head movements were noticed during induction in all the animals of group I but not in animals of Group II. The duration of anaesthesia was 33.67 +5.88 min, 57.83 + 6.17 min, and 89.00 +2.86 min in subgroups IA, IB and IC respectively, whereas it was for 49.67 + 6.643 min, 105.17 + 10.31 min AND 125.83 + 10.78 min in subgroups IIA, IIB and IIC respectively. An increase in the dose of tiletamine – zolazepam had prolonged the duration of anaesthesia and premedication with xylazine produced still longer duration of anaesthesia. The jaw musculature maintained the tonus with the lower doses of tiletamine – zolazepm, but at 15 mg/kg bodyweight, the jaw muscles, though not fully relaxed, permitted endotracheal intubation. Administration of tiletamine – zolazepam with xylazine resulted in relaxation of the jaw muscles and permitted endotracheal intubation. Relaxation of the abdominal muscles was moderate to good when tiletamine – zolazepam alone was administered, whereas it was excellent with xylazine premedication. Administration of tiletamine – zolazepam alone was found insufficient for carrying out surgical procedures, but with xylazine premedication muscle relaxation and analgesia was satisfactory. The recovery time was 111.50 + 14.53 min, 116.50 + 10.46 min and 180.33 + 10.57 min in subgroups IA,IB and IC respectively, and it was 160.00 + 17.70 min, 180.00 + 14.94 min and 181.06 + 12.82 min in subgroups IIA, IIB and IIC respectively. Increase in the dose of tiletamine – zolazepam had delayed recovery and xylazine premedication delayed it still further. During recovery, paddling and vocalization were common in dogs of group I but not in dogs of group II. Reduction in rectal temperature was observed only in animals of subgroups IB and IC and in all the animals of Group II. Marked increase in pulse rate was observed in group I than in Group II. Respiration rate was decreased in both the groups. A mild increase in diastolic pressure was observed in Group I. The systolic and diastolic pressure were seen decreased in Group II. The changes in the coagulation time of blood was within the normal limits in both the groups. Increase in heart rate with depression of T-wave, biphasic T-wave and spiking of T-wave were the changes in electrocardiogram. But the changes were corrected spontaneously. There was slight decrease in the erythrocyte sedimentation rate in animals of group I but there was no change in Group II. Reduction in the packed cell volume was observed in both the groups, but it was more, after xylazine premedication. Slight decrease in haemoglobin concentration was noticed in subgroup IC. But there was no change in Group II. Decrease in total erythrocyte count was noticed in both the group and the decrease was more when premedicated with xylazine. The total leukocyte count was seen increased in subgroup IA and IB but it was seen decreased in subgroup IC, but there was no change in group II. Decrease in lymphocyte count with increase in neutrophil count was observed in subgroups IA and IIA. In subgroups IB and IC there were increase in lymphocyte count with decrease in neutrophil count, but in subgroups IIB and IIC a decrease or no alteration in the count of lymphocytes was observed. Monocyte and eosinophil counts were increased and the basophil count remained insignificant. There was marked increase in the serum glucose value following the the administration of tiletamine – zolazepam and with xylazine premedication the increase was more. No significant change was observed in the serum electrolytes (Na+, K+, and Cl-), total serum protein content and serum urea nitrogen value in both the groups. Slight increase in serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) values were observed in Group I,and in Group II there was increase in AST value, but the ALT value decreased initially and was followed by an increase. Histopathological examination of liver revealed cloudy swelling and mild fatty changes and kidney revealed cystic dilation of the renal tubules along with focal areas of nephrosis.ThesisItem Open Access Evaluation of the efficacy of diaphragmatic and omental transplants at the gastroesophageal junction in dogs(Department of Surgery, College of Veterinary and Animal Sciences, Mannuthy, 1998) Sarada Amma, T; KAU; Muraleedharan Nayar, K NThe study was undertaken with the objectives of designing a surgical approach to the gastroesophageal region in dogs and to evaluate the efficacy of diaphragmatic and omental grafting at the gastroesophageal myotomy site. The study was conducted in 30 adult dogs of either sex divided into five groups of six animals each. The animals were premedicated with atropine sulphace (0.04 mg/kg body weight) and xylazine (0.5 mg/kg body weight) IM. Anaesthesia was induced and maintained with five per cent solution of thiopentone sodium to effect. Induction of anaesthesia and recovery was smooth and uneventful and the duration was satisfactory. Respiratory arrest observed in a few animals could be corrected except in one and respiration was maintained with respiration pump or Boyles' Tec anaesthetic apparatus. Gastroesophageal myotomy was performed through left side thoracotomy with resection of eighth rib in animals of Group I and by laparotomy, through the 12th intercostal space with resection of 12th rib in animals of Group 11, to study the suitability of surgical approaches. Abdominal approach adopted in Group II was found suitable for experimental approach and was adopted in animals of Groups III, IV and V. In the animals of Groups III, IV and V gastroesophageal myotomy was performed and the myotomy edges were sutured to the overlying portion of diaphragm in Group III, to a deflected portion of diaphragmatic pedicle graft in Group IV and to a deflected portion of omental pedicle graft in Group V. The animals were kept under observation for 21 days post operatively and observed for physiological changes, clinical signs, haematologic, radiographic and electrocardiogram changes. Physiological parameters showed a significant decrease in rectal temperature upto 90th min after surgery and significant increase in pulse and respiration rate upto 24 h. All the animals were alert and active throughout the period of observation. Feed intake and swallowing was normal. Skin wound had healed without complications in all the animals. Haemogram showed normal haemoglobin concentration, erythrocyte sedimentation rate and packed cell volume throughout the period of observation in all the animals. Erythrocyte count was within normal range in all the animals except for a transient decrease in Group I and leucocyte count showed an increase in Group V. An increase in neutrophil count was observed on the 7th and 14th day in Groups III and V with a corresponding decrease in lymphocyte count. Monocyte count was normal in all the animals and oesinophil count showed a decrease in Group I. The values returned to normal range by 21st day in all the animals. The electrocardiogram changes observed during surgery and in post operative period were spontaneously corrected. Contrast radiography of the oesophagus and stomach revealed normal emptying and absence of leakage. Narrowing' of the caudal end of thoracic oesophagus along with dilatation of the stomach was observed in one animal and dilatation of stomach alone was observed in two animals. Contrast radiography of the autopsy specimen of oesophagus and stomach of one animal each from Group I and 11 revealed increased width of gastroesophageal region and an outpouching of the stomach at the greater curvature. Gross morphological examination on autopsy in Group I revealed adhesion of lung with thoracic wall, diaphragm and oesophagus, congestion and consolidation of lung, collapse of the lung lobes and mediastinial pleuritis in a few animals. Fibrous tissue covering over the caudal end of thoracic oesophagus was also seen in two animals. Adhesion of omentum with abdominal wall and diaphragm was the autopsy changes noticed in Group 11. Oesophagus was normal in size in all the animals except in one animal where slight narrowing at the caudal end was observed. Increased width at the gastroesophageal region was evident in all the animals. An outpouching at the greater curvature of the stomach was seen in all animals except three where slight dilation and flaccidity of the stomach was noticed. The myotomy site was thin in Groups I, II and V. In Groups III, the portion of diaphragm sutured to the myotomy wound was firmly adherent with it and in Group IV, the diaphragm pedicle graft sutured to the myotomy wound has healed and was firmly adherent to the myotomy site. In Group V, the omental pedicle graft sutured to the myotomy site has healed completely and was indistinguishable. On histological examination no sign of inflammation was noticed in the mucosa and submucosa. . At the myotomy site fibrovascular connective tissue proliferation was observed in all the groups. In Groups III and IV peripheral to the fibrovascular connective tissue,the fascicles of diaphragmatic muscle fibrils were observed. In Group V beneath the thin fibrovascular layer infiltration of plasma cells, lymphocytes, macrophages and a few neutrophils were observed extending into the stroma and lamina propria. A layer of fibrous connective tissue was observed as the outermost layer over the thin fibrovascular layer and contained a few fat cells in one animal.