Capnographic documentation of nasoesophageal and nasogastric feeding tube placement in dogs

Objective: To evaluate the ability of capnography to document proper placement of nasoesophageal (NE) and nasogastric (NG) feeding tubes. This study was conducted in 3 phases. Phase I of this study was designed in order to test the efficacy of capnography to distinguish placement of a feeding tube in the alimentary tract versus the respiratory tract. Phase II was designed in order to document that carbon dioxide (CO₂) could be measured through a polyvinyl chloride (PVC) feeding tube. Phase III was performed in order to evaluate the technique of continuous monitoring during insertion of the feeding tube into the esophagus and stomach as would be performed during a clinical‐tube placement. Design: Prospective study. Setting: Research laboratory. Animals: 24 adult dogs. Interventions: In Phase I, sedated dogs were instrumented with an intratracheal catheter and an 8 French feeding tube placed nasally into the distal esophagus and later advanced into the stomach. In Phase II, dogs were anesthetized and an 8 French feeding tube was placed down the endotracheal tube, then into the esophagus and later advanced into the stomach. In Phase III, sedated dogs were instrumented with an 8 French feeding tube inserted intranasally and then advanced to the level of the nasopharynx, distal esophagus and, lastly, the stomach. Fluoroscopy was used in order to determine location of the feeding tube. Measurements and main results: Phase I measurements included respiratory rate and CO₂ from the trachea, esophagus, and stomach and pH of gastric fluid sample. Phase II measurements included respiratory rate and CO₂ from the endotracheal tube, feeding tube in the endotracheal tube, feeding tube in the distal esophagus, and feeding tube in the stomach. Phase III data collection included respiratory rate and CO₂ as the tube was passed through the nasal cavity, nasopharynx, esophagus and stomach. Phase I fluid samples were collected from 5 of the 9 dogs and had pH values from 1.68 to 4.20. In both phases, values for the respiratory rate and CO₂ from the esophagus and stomach were 0 ± 0, significantly lower (P < 0.001) than the values from the trachea. In Phase II, there was no significant difference between the respiratory rates (P = 0.886) and CO₂ (P = 0.705) readings obtained from the endotracheal tube compared to readings from the feeding tube in the endotracheal tube. In Phase III, there was a significant difference (P < 0.001) between the respiratory rates and CO₂ readings obtained from the nasal cavity and the nasopharynx when compared to those readings obtained from the esophagus and stomach. Measurement of CO₂ and respiratory rate resulted in a reading of 0 every time the feeding tube was in the esophagus or stomach. Conclusions: Capnography may be used in order to detect airway placement of NE and NG tubes.     

Determination of serum organic acids in puppies with naturally acquired parvoviral enteritis

The purpose of the present study was to investigate the acid-base status and the serum concentration of organic acids in puppies with naturally occurring canine parvoviral enteritis. Between July 1999 and July 2000, 25 client-owned puppies admitted to the St. Louis Animal Emergency Clinic South for treatment of enteritis caused by parvovirus infection were used in our study. Control blood samples were collected from 22 healthy puppies less than 9 months of age. Serum organic acid concentrations were quantitatively determined by HPLC. Puppies infected with parvovirus had significantly lower plasma concentrations of sodium, potassium, chloride, and bicarbonate than controls. Although serum L-lactate tended to increase in some puppies with canine parvoviral enteritis, our study demonstrated that most affected puppies developed only mild compensated metabolic acidosis. None of the affected puppies had an elevated serum D-lactate concentration at admission.     

Comparison of unilateral versus bilateral nasal catheters for oxygen administration in dogs

Objective: To determine the effect of bilateral nasal oxygen supplementation on tracheal airway and arterial blood gas parameters. Design: Original research. Setting: Research Laboratory. Animals: Eight normal dogs. Interventions: None. Measurements: Intra‐tracheal oxygen concentration and arterial oxygen partial pressure at three different oxygen flow rates given through either unilateral or bilateral nasal catheters. Main results: F_IO₂ and PaO₂ were significantly increased with higher total oxygen flow rates, but the increase was the same whether the higher flow was delivered through one nasal catheter or divided and administered though two nasal catheters. The use of bilateral nasal catheters allowed a tracheal F_IO₂ as high as 0.60 with minimal patient discomfort. Conclusions: The benefit of bilateral nasal catheters for oxygen supplementation is the ability to provide high total oxygen flows with decreased risk of patient discomfort. If the desired oxygen flow can be achieved with a unilateral nasal catheter, then the only benefit of bilateral catheters is increased patient comfort. The use of bilateral nasal oxygen catheters for oxygen supplementation can result in an F_IO₂ that is high enough to produce oxygen toxicity with prolonged administration.     

Evaluation of the formulated diet MySpat for feeding hatchery‐reared spat of the green‐lipped mussel,Perna canaliculus (Gmelin, 1791)

As with most bivalves, a high cost component of hatchery and nursery culture of the green‐lipped mussel (Perna canaliculus) is the raising of live micro‐algae feeds. To remedy this, artificial feeds have been developed, however, these have had mixed success for this species. In this experiment, we tested the formulated diet MySpat (sourced from INVE Aquaculture) on P. canaliculus spat of approximately 1 mm in size. Performance measures under study were mussel spat growth and survivorship after 21 days feeding on varying proportions of MySpat. The experimental diets tested, consisted of a mix of T‐Isochrysis galbana, Pavlova lutheri and Tetraselmis suecica micro‐algae that were replaced with increasing proportions of MySpat, i.e. 25%, 50%, 67%, 75%, 90% and 100% MySpat replacement. Our results revealed no significant increase in spat mortality with increasing MySpat diet levels, and growth was equivalent to the micro‐algae only dietary control in all diets except the 90% and 100% MySpat replacement diets. Such results highlight the role MySpat could have for P. canaliculus hatchery operations, particularly with regard to reducing the costs of raising micro‐algae when producing seed for industry. A greater understanding of the particle selection process of this species would be beneficial for future studies seeking to employ artificial diets.     

Cell-directed assembly of lipid-silica nanostructures providing extended cell viability

Amphiphilic phospholipids were used to direct the formation of biocompatible, uniform silica nanostructures in the presence of Saccharomyces cerevisiae and bacterial cell lines. The cell surfaces organize multilayered phospholipid vesicles that interface coherently with the silica host and help relieve drying stresses that develop with conventional templates. These host structures maintain cell accessibility, addressability, and viability in the absence of buffer or an external fluidic architecture. The cell surfaces are accessible and can be used to localize added proteins, plasmids, and nanocrystals. Prolonged cell viability combined with reporter protein expression enabled stand-alone cell-based sensing.     

Cis-trans isomerism in naphthoquinones: interconversion and participation in oxidative phosphorylation

Synthetic phylloquinone was resolved into cis and trans isomers by thin-layer chromatography. The two isomers had identical ultraviolet spectra characteristic of vitamin K(1) and were differentiated by nuclear-magnetic-resonance spectroscopy on the basis of the displacement of the peak corresponding to the olefinic methyl group in the naphthoquinone side chain. Studies on the restoration of electron transport coupled to phosphorylation in irradiated preparations of Mycobacterium phlei showed that only the trans isomer was active with substrates linked to nicotinamide-adenine dinucleotide. The purified trans phylloquinone was enzymatically converted to the cis isomer. Under similar conditions, cis vitamin K(1) gave rise to the trans-naphthoquinone. The natural naphthoquinone of M. phlei vitamin MK(9)(II-H) was similarly resolved into cis and trans isomers.     

Selective particle feeding by the Chilean oyster, Ostrea chilensis; implications for nursery culture and broodstock conditioning

Hatchery broodstock conditioning and nursery culture of the Chilean flat oyster Ostrea chilensis have been hampered by the poor performance of oysters fed typical microalgal hatchery diets. To determine the feeding capabilities of this species the selective removal and consumption of natural planktonic assemblages and artificial inert particles (polystyrene beads) by juvenile and adult oysters were examined experimentally. The arrangement of the eulaterofrontal cirri of the ctenidia was also examined to infer their potential efficiency of particle selection for feeding. Polystyrene beads of 45 and 15 μm in diameter had high rates of removal from suspensions by both juvenile (45 μm = 70%, 15 μm = 73%) and adult (45 μm = 88%, 15 μm = 87%) oysters. In contrast, beads of 6 μm diameter had lower rates of removal (adults = 68%, juveniles = 53%), while 1 μm beads were not removed at all. Both adult and juvenile oysters feeding upon natural plankton assemblages removed only microphytoplankton (20-75 μm in size) despite the presence of nanophytoplankton (2-20 μm), picophytoplankton (< 2 μm), cyanobacterium Synechoccocus spp. (< 2 μm), and bacterial cells (< 75 μm) in the experimental suspensions. Eulaterofrontal cirri of both juvenile (15.2 μm ± 0.9 SE) and adult oysters (18.9 μm ± 0.3 SE) are the shortest that have been reported for any ostreid species which helps to explain the inability of this species to retain small food particles. The clearance rates for oysters feeding on microphytoplankton only were 1.49 (± 0.05 SE) and 7.1 (± 1.2 SE) l h^− 1g^− 1 for juveniles and adults respectively. These values are much higher than previously reported for this species being fed smaller sized cultured microalgae. Our results strongly suggest that the difficulties in the nursery and broodstock hatchery culture of this oyster may be due to inappropriate phytoplankton diets. We recommend the provision of cultured microalgae of 20-75 μm in diameter for improving the performance of hatchery maintained juvenile and adult O. chilensis.     

Recurrence rate of presumed thoracolumbar intervertebral disc disease in ambulatory dogs with spinal hyperpathia treated with anti-inflammatory drugs: 78 cases (1997–2000)

Objective: To determine the recurrence rate of clinical signs in dogs with spinal hyperpathia and mild neurological deficits due to presumed Hansen Type 1 thoracolumbar intervertebral disc disease (IVDD) that were managed medically with anti‐inflammatory agents, and to compare the recurrence rates between dogs treated with corticosteroids and those treated with nonsteroidal anti‐inflammatory drugs (NSAIDs). Design: Retrospective study. Setting: Private veterinary emergency clinic in a large metropolitan area. Animals, interventions, and measurements: Medical records were used to ascertain study eligibility, record patient signalment and condition severity, and document medical treatment regimen. Each dog was assigned a severity score: (1) spinal hyperpathia with no neurological deficits, (2) spinal hyperpathia with conscious proprioceptive deficits only, or (3) spinal hyperpathia with ataxia but still retaining ambulatory motor function. Owners of 78 dogs weighing less than 16 kg presented from 1997 through 2000 were sent a questionnaire to determine recurrence rate. Main results: All dogs recovered from the initial episode; 39 experienced recurrence and 39 did not. There was no statistically significant relationship between gender, age, or severity score and recurrence rate. Dogs treated with NSAIDs or methylprednisolone sodium succinate (MPSS) were less likely to experience recurrence than dogs treated with corticosteroids other than MPSS. Conclusion: A 50% recurrence of presumed IVDD occurred in this population of dogs after treatment with NSAIDs or corticosteroids. Those treated with NSAIDs or MPSS were less likely to experience a recurrence.     

IN VITRO EVALUATION OF CONTRAST MEDIUM CONCENTRATION AND DEPTH EFFECTS ON THE RADIOGRAPHIC APPEARANCE OF SPECIFIC CANINE UROLITH MINERAL TYPES

Nine pure mineral types of canine uroliths (bladder or urethral origin only) identified in a chronologic sample from the Minnesota Urolith Center were compared to sequential dilutions of iodinated radiographic contrast medium in vitro. The uroliths studied were those composed of 100% magnesium ammonium phosphate, calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate appatite, calcium hydrogen phosphate dihydrate (brushite), ammonium acid urate, sodium acid urate, cystine, and silica. The radiopacity of the uroliths was classified as radiolucent, isopaque, or radiopaque, as compared to the radiopacity of the contrast medium solutions in which they were placed, using 2.0 mm and 5.0 mm depths in petri dishes radiographed using a table-top technique. A statistically significant relationship was found between the effective atomic number of the uroliths and the effective atomic number of the contrast medium solutions to which they were compared for the endpoints of isopacity, first luceney (in increasing iodine concentration sequence), and optimal visualization of internal architecture. In general, uroliths isopaque or radiolucent in contrast medium solutions weaker than 23.5 mgI₂/ml are most likely ammonium acid urate or sodium acid urate. Uroliths isopaque or radiolucent in contrast medium solutions between 23.5 mgI₂/ml and 44.4 mgI₂/ml are probably magnesium ammonium phosphate, cystine, or silica. Uroliths that remained radiopaque in solutions stronger than 44.4 mgI₂/ml, and particularly those radiopaque in contrast medium solutions stronger than 80 mgI₂/ml, almost always contained calcium. This relative opacity assessment is proposed for use in double contrast cystography as an aid in differentiating urolith mineral types clinically to facilitate appropriate use of medical protocols to dissolve uroliths or to prevent their growth or recurrence.