Intersex in the clam Scrobicularia plana (Da Costa): Widespread occurrence in English Channel estuaries and surrounding areas.

Estuarine clams Scrobicularia plana were sampled from 108 intertidal locations around the English Channel and adjacent areas. Although S. plana is believed to be a strict gonochorist, 58% of the populations sampled included intersexed individuals (described as male clams exhibiting ovotestis). Over the entire region, on average, 8.6% of male clams exhibited intersex, although proportions of affected males ranged from 0% to 53% depending on location. The severity of intersex was assessed using a simple classification scale, with the majority of individuals showing low levels of impact. Sex ratios were significantly skewed at some sites. There were no significant relationships between incidence or severity of intersex; or with size or parasitism of individual clams. Intersex in S. plana is a useful tool to assess endocrine disruptive effects in estuaries, although mechanisms of impact and causative agents remain uncertain.

Recovery from TBT pollution in English Channel environments: A problem solved?

Following recognition of effects in the 1980s, tributyltin (TBT) has been monitored at sites in the English Channel to evaluate the prognosis for biota - spanning the introduction of restrictions on TBT use on small boats and the recent phase-out on the global fleet. We describe how persistence and impact of TBT in clams Scrobicularia plana has changed during this period in Southampton Water and Poole Harbour. TBT contamination (and loss) in water, sediment and clams reflects the abundance and type of vessel activity: half-times in sediment (up to 8y in Poole, 33y in Southampton) are longest near commercial shipping. Recovery of clam populations - slowest in TBT-contaminated deposits - provides a useful biological measure of legislative efficacy in estuaries. On rocky shores, recovery from imposex in Nucella lapillus is evident at many sites but, near ports, is prolonged by shipping impacts, including sediment legacy, for example, in the Fal.

Predictive factors and the effect of phenoxybenzamine on outcome in dogs undergoing adrenalectomy for pheochromocytoma.

BACKGROUND: Some studies in dogs undergoing adrenalectomy for pheochromocytoma suggest that anesthetic complications and perioperative mortality are common. In humans, surgical outcome has improved with the use of phenoxybenzamine (PBZ) before adrenalectomy. HYPOTHESIS: Dogs treated with PBZ before adrenalectomy have increased survival compared with untreated dogs. ANIMALS: Forty-eight dogs that underwent adrenalectomy for pheochromocytoma. METHODS: A retrospective medical record review for dogs that underwent adrenalectomy for pheochromocytoma at a veterinary medical teaching hospital over the period from January 1986 through December 2005. RESULTS: Twenty-three of 48 dogs were pretreated with PBZ (median dosage: 0.6 mg/kg PO q12h) for a median duration of 20 days before adrenalectomy. Duration of anesthesia and surgery, percentage of dogs with pheochromocytoma involving the right versus left adrenal gland, size of tumor, and presence of vascular invasion were similar for PBZ-treated and untreated dogs. Thirty-three (69%) of 48 dogs survived adrenalectomy in the perioperative period. PBZ-treated dogs had a significantly (P = .014) decreased mortality rate compared with untreated dogs (13 versus 48%, respectively). Additional significant prognostic factors for improved survival included younger age (P = .028), lack of intraoperative arrhythmias (P = .0075), and decreased surgical time (P = .0089). CONCLUSIONS AND CLINICAL IMPORTANCE: Results from this retrospective study support treatment with PBZ before surgical removal of pheochromocytoma in dogs.

Magnetic resonance imaging findings in Finnish Spitz dogs with focal epilepsy.

Eleven Finnish Spitz dogs with focal seizures and 3 healthy controls were evaluated. General clinical and neurological examinations, blood examination, urinalysis, cerebrospinal fluid examination, electroencephalography (EEG), and magnetic resonance imaging (MRI) of the brain were performed on all dogs. On EEG examination, focal epileptic activity was found in 7 of 11 dogs (64%), and generalized epileptic activity was observed in 4 of 11 dogs (36%). MRI (performed with 1.5 T equipment) detected changes in 1 epileptic dog. Mild contrast enhancement after gadolinium injection was identified in this dog's right parietal cortex. However, no such changes were observed in repeated magnetic resonance images. Special emphasis was given to seizure history to determine any correlations between seizure intervals and MRI findings. Our results indicate that Finnish Spitz dogs with focal seizures suffer from focal idiopathic epilepsy and have nondetectable findings on MRI or pathology. MRI showed poor sensitivity in detecting epileptogenic areas in our patients with focal seizures. Reversible MRI changes in 1 dog could have been caused by seizures.

Evaluation of a portocaval venograft and ameroid ring for the occlusion of intrahepatic portocaval shunts in dogs.

OBJECTIVE: To evaluate the use of a portocaval venograft and ameroid constrictor in the surgical management of intrahepatic portosystemic shunts (PSS). STUDY DESIGN: Prospective, clinical study. ANIMAL POPULATION: Ten client-owned dogs with intrahepatic PSS. METHODS: Portal pressure was measured after temporary suture occlusion of the intrahepatic PSS. In dogs with an increase in portal pressure greater than 8 mm Hg, a single extrahepatic portocaval shunt was created using a jugular vein. An ameroid ring was placed around the venograft and the intrahepatic PSS was attenuated. Transcolonic pertechnetate scintigraphy was performed before surgery, 5 days after surgery, and 8 to 10 weeks after surgery. Dogs with continued portosystemic shunting were evaluated further by laparotomy or portography. Clinical outcome and complications were recorded. RESULTS: Mean (+/- SD) portal pressure increased from 6 +/- 3 to 19 +/- 6 mm Hg with PSS occlusion; in all 10 dogs, the increase in portal pressure was greater than 8 mm Hg. There were no intraoperative complications, and, after creation of the portocaval shunt, the intrahepatic PSS could be completely ligated in 8 of 10 dogs. The final portal pressure was 9 +/- 4 mm Hg. Postoperative complications included coagulopathy and death (1 dog), ascites (3 dogs), and incisional discharge (3 dogs). Five of 8 dogs had continued portosystemic shunting at 8 to 10 weeks after surgery. Multiple extrahepatic PSS were demonstrated in 4 of these dogs. Clinical outcome was excellent in all 9 surviving dogs. CONCLUSIONS AND CLINICAL SIGNIFICANCE: The surgical technique resulted in a high incidence of multiple extrahepatic PSS. Short-term clinical results were promising, but long-term outcome must be evaluated further.

Periparturient and neonatal anesthesia.

Small animal patients may need to be anesthetized in the periparturient period for emergency, nonobstetric reasons, elective ovariohysterectomy, or cesarean section. In each case, the physiologic changes in the dam must be accounted for in designing an anesthetic protocol, but the requirements of the fetuses will be different. Subsequent to birth, the neonatal animal may need to be anesthetized, and the unique physiology and pharmacology at this age is described.

Neonatal critical care.

The first few minutes after a neonate's birth may determine the quality of its entire life. Immediate care includes prevention of hypothermia, clearing of nasal and oral passages, stimulation of ventilation and oxygenation, and, in a few cases, advanced life support. Any additional stress during the first weeks of life can also result in neonatal morbidity and mortality. Care of the diseased newborn must focus not only on treatment of the underlying disease but on aggressive supportive care. A safe, warm, clean, proper environment and adequate nutrition are essential.

Effects of xylazine hydrochloride during isoflurane-induced anesthesia in horses.

OBJECTIVE: To quantitate dose- and time-related anesthetic-sparing effects of xylazine hydrochloride (XYL) during isoflurane-induced anesthesia in horses and to characterize selected physiologic responses of anesthetized horses to administration of XYL. ANIMALS: 6 healthy adult horses. PROCEDURE: Horses were anesthetized 2 times to determine the minimum alveolar concentration (MAC) of isoflurane in O2 and to characterize the anesthetic-sparing effect (MAC reduction) after IV administration of XYL (0.5 and 1 mg/kg of body weight, random order). Selected measures of cardiopulmonary function, blood glucose concentrations, and urinary output also were measured during the anesthetic studies. RESULTS: Isoflurane MAC (mean +/- SEM) was reduced by 24.8 +/- 0.5 and 34.2 +/- 1.9% at 42 +/- 7 and 67 +/- 10 minutes, respectively, after administration of XYL at 0.5 and 1 mg/kg. Amount of MAC reduction by XYL was dose- and time-dependent. Overall, cardiovascular and respiratory values varied little among treatments. Administration of XYL increased blood glucose concentration; the magnitude of change was dose- and time-dependent. Urine volume increased but not significantly. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of XYL reduced the anesthetic requirement for isoflurane in horses. The magnitude of the decrease is dose- and time-dependent. Administration of XYL increases blood glucose concentration in anesthetized horses in a dose-related manner.

Opioid analgesics.

Opioids are useful and potent drugs for the management of pain in small animal patients. They have a wide therapeutic index and can be given by a number of different routes. Some of these techniques (e.g., epidural and intraarticular) allow for the production of profound analgesia in a localized area of the body while limiting the dose and the side effects, and others provide a noninvasive method for the delivery of continuous analgesia (e.g., transdermal administration).

Perioperative pain management.

The management of perioperative pain starts with the use of approaches to minimize anxiety and distress before the procedure. The administration of analgesics or local anesthetics before the start of surgery reduces the nociceptive input occurring during the procedure and reduces the need for postoperative analgesics. As the animal recovers from anesthesia, it is important to administer analgesics to minimize the patient's experience of pain and to continue this therapy through at least the first 12 to 24 hours. Techniques that provide a continuous level of analgesia are more effective than those that allow the pain to return.

Perioperative risk factors for puppies delivered by cesarean section in the United States and Canada.

The purpose of this study was to evaluate perioperative risk factors affecting neonatal survival after cesarean section. Data from 807 cesarean-derived litters (3,908 puppies) was submitted by 109 practices in the United States and Canada. Survival rates immediately, two hours, and seven days after delivery were 92% (n=3,127), 87% (n=2,951), and 80% (n=2,641), respectively, for puppies delivered by cesarean section (n=3,410) and were 86% (n=409), 83% (n=366), and 75% (n=283), respectively, for puppies born naturally (n=498). Maternal mortality rate was 1% (n=9). Of 776 surgeries, 453 (58%) were done on an emergency basis. The most common breed of dog was bulldog (n=138; 17%). The most common methods of inducing and maintaining anesthesia were administration of isoflurane for induction and maintenance (n=266; 34%) and administration of propofol for induction followed by administration of isoflurane for maintenance (n=237; 30%). A model of cesarean-derived puppies surviving to birth, between birth and two hours, and between two hours and seven days was designed to relate litter survival to perioperative factors. The following factors increased the likelihood of all puppies being alive: the surgery was not an emergency; the dam was not brachycephalic; there were four puppies or less in the litter; there were no naturally delivered or deformed puppies; all puppies breathed spontaneously at birth; at least one puppy vocalized spontaneously at birth; and neither methoxyflurane nor xylazine was used in the anesthetic protocol.

Systemic effects of topical and subconjunctival ophthalmic atropine in the horse.

OBJECTIVE: To identify any systemic effects of topical and subconjunctival administration of atropine sulfate in the horse. Animals studied Six mature grade horses were treated hourly in one eye with topical ophthalmic atropine drops for 24 h. Five horses were treated subconjunctivally in one eye with 3 mg of atropine sulfate. Procedures Pupillary light reflexes, pupil size, electrocardiographic parameters, girth measurements, intestinal motility, and clinical signs of abdominal pain were monitored. RESULTS: Alteration in auscultated gut motility and clinical signs of abdominal pain were the most sensitive indicators of the systemic manifestations of the topically applied atropine. Gut motility was absent in all horses for periods of 2-18 h in all four abdominal quadrants in horses given topically administered atropine. Signs of abdominal pain were observed in four of six horses that received topical atropine. In the subconjunctival test study, gut motility was absent in three horses for periods of 3-7 h. Uniocular subconjunctival injection of 3 mg atropine sulfate produced signs of abdominal pain in one of six horses. Conclusion The ophthalmic administration of atropine can affect gut motility and induce signs of colic in selected horses.

Modification and application of a Pelorus Mark III stereotactic system for CT-guided brain biopsy in 50 dogs.

The Pelorus Mark III Stereotactic System is a commercially available device for CT-guided stereotactic brain biopsy in people. With relatively minor modifications, this device was used to safely and accurately perform CT-guided stereotactic brain biopsies in 50 dogs with intracranial lesions. Modifications were necessary to accommodate a 90 degree shift in orientation of the canine head compared to the human head during the imaging phase of the procedure, and to facilitate other phases of the biopsy procedure that are affected by the uneven and variable topography of the canine skull. Description of a typical CT-guided brain biopsy procedure in dogs using the modified Pelorus Mark III Stereotactic System is provided. Accuracy of biopsy needle placement was determined by comparing the x, y and z coordinates of the biopsy target site with the actual coordinates of the needle tip on CT images. Mean needle placement error was 3.5 +/- 1.6 mm. Needle placement error was not significantly related to operator experience, dog size (body weight), or needle path length, however, needle placement error was significantly affected by lesion location.

Haemodynamic effects of ATP in dogs during hypoxia-induced pulmonary hypertension.

Pulmonary hypertension may result from an increase in vascular resistance caused by persistent hypoxia. We have investigated the effects of adenosine triphosphate (ATP), administered into the pulmonary artery, on haemodynamic changes occurring in anaesthetized adult dogs subjected to acute hypoxic pulmonary vasoconstriction. Hypoxia alone (ventilation with 10% O2/90% N2) caused significant increases in mean pulmonary arterial blood pressure (PAP), central venous pressure (CVP), and cardiac index (CI) by 71, 102 and 38%, respectively. ATP (0.03-3.0 micromol/kg/min approximately 0.02-1.65 mg/kg/min), when infused under hypoxic conditions, significantly reduced both mean PAP and systemic arterial blood pressure (ABP) in a dose-dependent manner. The maximum decrease in mean PAP amounted to 20%; mean ABP, on the other hand, was decreased by up to 52% (P<0.01). Heart rate, CI, CVP and pulmonary occlusion pressure were not dose-dependently affected by ATP. Our data indicate that while pulmonary arterial administration of ATP in mature dogs during hypoxic pulmonary hypertension causes dilation in the pulmonary vascular bed, it is even more effective in dilating the systemic vasculature. This result suggests a need for further evaluation and warrants cautious use of ATP in the treatment of hypoxic pulmonary hypertension in adult dogs.

Anaphase aberrations in the embryos of the marine tubeworm Pomatoceros lamarckii (Polychaeta: Serpulidae): a new in vivo test assay for detecting aneugens and clastogens in the marine environment.

The marine environment receives a wide variety of chemical inputs, many of which have the potential to damage DNA or interfere with the process of cell division. Here we describe a new assay based on the early embryo and larval stages of a planktonic spawning, tube dwelling marine worm, Pomatoceros lamarckii, which for experimental purposes has the advantage of producing large numbers of ripe gametes throughout the majority of the year. One of the most promising end-points is the use of dividing cells to detect anaphase aberrations such as lagging chromosomes, tripolar anaphases, acentric fragments and chromosome bridges. Apart from the reference mutagens mitomycin C and cyclophosphamide and the well-documented spindle poison colchicine, we tested the fungicide carbendazim, a primary metabolite of the fungicide benomyl, and thiabendazole, a pesticide and antihelminthic drug; both of which are known to act as aneugens in other test systems. In addition we tested sodium hypochlorite, a widely used oxidizing agent and disinfectant, di-butylphthalate, a commercial plasticizer and suspected aneugen, and sodium chloride, a recognized non-genotoxin. Significant increases in the frequency of anaphase abnormalities occurred with most test compounds at relatively low concentrations, confirming the sensitivity of the new assay. Sodium chloride yielded a negative response except at the highest non-relevant concentrations, where some chromatid stickiness was observed. In addition, the developmental consequences of exposure to these compounds were assessed in 4-8 cell embryos and at 48 h once the embryos had metamorphosed into free swimming larvae. Mitotic inhibition and anaphase aberrations were found to be a more sensitive indicator of genotoxic exposure than larval development, although there was a suggestion of a possible mechanistic link between aneugenicity/clastogenicity and larval fitness. The new test assay provides a rapid and inexpensive method for screening chemicals and effluents destined for release into the marine environment for potential gamete effects.

Effects of intravenously administered glycopyrrolate in anesthetized horses.

The purpose of this study was to determine the heart rate (HR) and blood pressure (BP) effect of glycopyrrolate in anesthetized horses with low HR (< or = 30 beats/min). The horses were randomly treated with glycopyrrolate (2.5 micrograms/kg body weight (BW)) or saline, intravenously (i.v.) (n = 17). If HR failed to increase (by > 5 beats/min within 10 min), glycopyrrolate (same dose) was administered. Heart rate increased by > 5 beats/min in 3 out of 9 horses following the initial glycopyrrolate treatment. Overall changes in HR and mean BP were not significantly different, while systolic and diastolic BP increased significantly (P < 0.025 using a Bonferroni corrected paired t-test). On the 2nd treatment, 3 out of 7 horses given 2.5 micrograms/kg BW glycopyrrolate, and 4 out of 5 horses given 5.0 micrograms/kg BW (total dose) showed an increase in heart rate of > 5 beats/min, which was significant. A significant increase in BP was produced following treatment with 2.5 micrograms/kg BW, but not following 5.0 micrograms/kg BW. A final increase in HR, of > 5 beats/min, was associated with a significant rise in BP (P < 0.05 using an unpaired t-test). In conclusion, an increase in HR can occur with 2.5 to 5.0 micrograms of glycopyrrolate/kg BW, i.v., and results in improvement in BP in anesthetized horses.

Comparison of two techniques for total intravenous anesthesia in horses.

OBJECTIVE: To characterize responses associated with two 1-hour total intravenous anesthesia techniques in horses. ANIMALS: 6 mature, healthy mares. PROCEDURE: Each horse was anesthetized 3 times. Treatment order was determined by a series of Latin squares. After baseline measurements and instrumentation, horses were given xylazine (XYL) i.v.; anesthesia was induced 5 minutes later with 10% guaifenesin given i.v., then either ketamine (KET) or propofol (PRO) was given i.v. After anesthesia induction, each horse received an infusion of XYL and either KET or a low or high dose of PRO. Cardiopulmonary variables were measured at 20, 40, and 60 minutes after the start of the infusion; arterial blood samples were collected prior to each set of measurements, and blood gas tensions and plasma drug concentration were determined. A noxious stimulus was applied after each of the 3 sets of measurements. RESULTS: Differences in measured cardiopulmonary variables were significant among all treatments at different times. Most notable differences were between KET and high PRO. Times to regaining sternal and standing posture were shortest for KET, and differed significantly from values for low and high PRO. Purposeful responses were not observed for high PRO in horses after noxious stimulation. In contrast, 4 horses given KET responded at all time points and 1 horse given low PRO responded. CONCLUSION: None of the infusion techniques were flawless, but results support continued efforts at technique refinement and selected clinical use.

Perioperative management and mortality rates of dogs undergoing cesarean section in the United States and Canada.

OBJECTIVE: To describe dogs undergoing cesarean section in the United States and Canada, to determine perioperative management, and to calculate survival proportions. DESIGN: Multicenter prospective case series. ANIMALS: 3,908 puppies from 808 dams. RESULTS: Survival rates immediately, 2 hours, and 7 days after delivery were 92, 87, and 80%, respectively, for puppies delivered by cesarean section (n = 3,410) and 86, 83, and 75%, respectively, for puppies born naturally (498). For 614 of 807 (76%) litters, all puppies delivered by cesarean section were born alive. Maternal mortality rate was 1% (n = 9). Of 776 surgeries, 453 (58%) were done on an emergency basis. The most common breeds of dogs that underwent emergency surgery were Bulldog, Labrador Retriever, Boxer, Corgis, and Chihuahua. The most common breeds of dogs that underwent elective surgery were Bulldog, Labrador Retriever, Mastiff, Golden Retriever, and Yorkshire Terrier. The most common methods of inducing and maintaining anesthesia were administration of isoflurane for induction and maintenance (n = 266; 34%) and administration of propofol for induction followed by administration of isoflurane for maintenance (237; 30%). CLINICAL IMPLICATIONS: Mortality rates of dams and puppies undergoing cesarean section in the United States and Canada are low. Knowledge of mortality rates should be useful to veterinarians when advising clients on the likelihood of puppy and dam survival associated with cesarean section.