Effect of continuous intravenous administration of a 50% dextrose solution on phosphorus homeostasis in dairy cows

OBJECTIVE: To determine the effect of continuous IV administration of 50% dextrose solution on phosphorus homeostasis in lactating dairy cows. DESIGN: Clinical trial. ANIMALS: 4 multiparous Jersey cows. PROCEDURES: Cows were administered 50% dextrose solution IV (0.3 g/kg/h [0.14 g/lb/h]) for 5 days. Plasma concentrations of glucose, immune-reactive insulin (IRI), and phosphorus were determined before, during, and for 72 hours after dextrose infusion. Phosphorus intake and losses of phosphorus in urine, feces, and milk were determined. Each cow received a sham treatment that included instrumentation and sampling but not administration of dextrose. RESULTS: Plasma glucose, IRI, and phosphorus concentrations were stable during sham treatment. Plasma phosphorus concentration decreased rapidly after onset of dextrose infusion, reaching a nadir in 24 hours and remaining less than baseline value for 36 hours. Plasma phosphorus concentration increased after dextrose infusion was stopped, peaking in 6 hours. Urinary phosphorus excretion did not change during dextrose infusion, but phosphorus intake decreased because of reduced feed intake, followed by decreased fecal phosphorus loss and milk yield. Rapid changes in plasma phosphorus concentration at the start and end of dextrose infusion were temporally associated with changes in plasma glucose and IRI concentrations and most likely caused by compartmental shifts of phosphorus. CONCLUSIONS AND CLINICAL RELEVANCE: Hypophosphatemia developed in response to hyperglycemia or hyperinsulinemia in dairy cows administered dextrose via continuous IV infusion. Veterinarians should monitor plasma phosphorus concentration when administering dextrose in this manner, particularly in cows with decreased appetite or preexisting hypophosphatemia.     

Successful treatment of a pancreatic pseudocyst by omentalisation in a dog

CASE HISTORY A 3-year-old male Labrador retriever was presented with a history of dietary indiscretion followed by vomiting and abdominal pain.

CLINICAL FINDINGS AND TREATMENT: Abdominal ultrasonography revealed the presence of a fluid-filled cystic structure in the region of the pancreas. Flocculent, dark fluid was drained from the cystic structure during exploratory celiotomy prior to resection of the lateral cystic wall. Omentum was sutured into the cystic cavity to provide drainage and enhance immune response. A jejunostomy feeding tube was placed. Post-surgical care consisted of antibiotic therapy. The dog was clinically normal at 1 and 7 months post-operatively and the pancreas appeared normal on final ultrasonographic examination.

CLINICAL RELEVANCE: This case describes the use of omentum to provide physiological drainage of a pancreatic pseudocyst. This surgical technique may help clinicians manage patients with this condition in the future.     

In vivo and in vitro efficacy of zoledronate for treating oral squamous cell carcinoma in cats

BACKGROUND: Feline oral squamous cell carcinoma (OSCC) may cause painful bone destruction. Given the local invasiveness and rapid clinical progression of OSCC, conventional therapies are often palliative. In human cancer patients, zoledronate exerts anticancer effects by inhibiting tumor-induced angiogenesis and malignant osteolysis. HYPOTHESIS: Zoledronate will exert in vitro and in vivo anti-angiogenic and antiresorptive effects in feline OSCC. ANIMALS: Eight cats with OSCC were prospectively treated with zoledronate and conventional treatment modalities. METHODS: In vitro, zoledronate's effects in modulating soluble vascular endothelial growth factor (VEGF) secretion and receptor activator of nuclear factor kappaB (NF-kappaB) ligand (RANKL) expression were investigated in a feline OSCC cell line (SCCF1). In vivo, basal serum C-telopeptide (CTx) concentrations were compared among normal and OSCC-bearing cats, and the biologic effects of zoledronate administration in cats with naturally occurring OSCC were quantified by serially assessing circulating serum VEGF and CTx concentrations. RESULTS: In vitro, zoledronate concentrations greater than 3 microM reduce soluble VEGF secretion in the SCCF1 cell line. The expression of RANKL in the SCCF1 cell line was also modulated by zoledronate, with low concentrations (3 microM) decreasing but higher concentrations (30 microM) increasing RANKL expression in comparison with untreated cells. In vivo, cats with bone-invasive OSCC had greater serum CTx concentrations in comparison with geriatric, healthy controls. Treatment with zoledronate rapidly decreased circulating serum VEGF and CTx concentrations in cats with spontaneously occurring OSCC. CONCLUSIONS AND CLINICAL IMPORTANCE: Zoledronate exerts in vitro and in vivo effects that may favor the slowing of tumor growth and pathologic bone turnover associated with OSCC.     

Reduction in the mRNA expression of sVEGFR1 and sVEGFR2 is associated with the selection of dominant follicle in cows

The vascular endothelial growth factor (VEGF) is essential for follicular development by promoting follicular angiogenesis, as well as for the proliferation and survival of granulosa cells. The biological effects of VEGF are regulated by two membrane receptors, VEGFR1 and VEGFR2, and two soluble receptors, sVEGFR1 and sVEGFR2, which play an antagonistic role. Thus, the objective of this study was to identify the mRNA expression pattern of total VEGF, VEGFR1, VEGFR2, sVEGFR1 and sVEGFR2 in bovine preselected follicles (PRF) and post‐selected follicles (POF). The mRNA expression of these five genes in both granulosa cells (GC) and theca cells (TC) was compared between follicles classified as PRF and POF based on their diameter and on their ratio of estradiol/progesterone (E2/P4). Results showed a lower expression of mRNA of sVEGFR1 and sVEGFR2 in POF than in PRF (p < .05). Regarding the mRNA expression of total VEGF, VEGFR1 and VEGFR2, there was no difference between POF and PRF follicles (p > .05). Our results showed that the mRNA expression of VEGFR2 and sVEGFR1 was more abundant than the expression of VEGFR1 and sVEGFR2, while GC was the main source of mRNA for total VEGF. On the other hand, TC was the follicular compartment where the receptors were most expressed. Our results suggest that non‐dominant follicles maintain a greater concentration of the mRNA expression of both membrane and soluble VEGF receptors. On the other hand, follicular dominance is related to a reduction in the mRNA expression of sVEGFR1 and sVEGFR2, which may favour VEGF binding with VEGFR2 and, hence, improve the follicular health and development.     

Shape transition of germanium nanocrystals on a silicon (001) surface from pyramids to domes

Chemical vapor deposition of germanium onto the silicon (001) surface at atmospheric pressure and 600 degrees Celsius has previously been shown to produce distinct families of smaller (up to 6 nanometers high) and larger (all approximately 15 nanometers high) nanocrystals. Under ultrahigh-vacuum conditions, physical vapor deposition at approximately the same substrate temperature and growth rate produced a similar bimodal size distribution. In situ scanning tunneling microscopy revealed that the smaller square-based pyramids transform abruptly during growth to significantly larger multifaceted domes, and that few structures with intermediate size and shape remain. Both nanocrystal shapes have size-dependent energy minima that result from the interplay between strain relaxation at the facets and stress concentration at the edges. A thermodynamic model similar to a phase transition accounts for this abrupt morphology change.     

Self-oriented regular arrays of carbon nanotubes and their field emission properties

The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology.     

Aspergillus flavus keratomycosis in a cat treated with topical 1% voriconazole solution

An 8-year-old male castrated Domestic Short-haired cat was examined for a 1-week history of blepharospasm and mucoid ocular discharge OS. Examination revealed ulcerative keratitis with stromal loss, stromal infiltrate, corneal edema, perilimbal vascularization and miosis. Cytology of the cornea revealed multiple dichotomously branching, septate fungal hyphae and severe, predominantly neutrophilic inflammation. PCR of the cytology samples confirmed the presence of Aspergillus flavus while fungal and bacterial cultures were negative. Treatment with topical 1% voriconazole solution was successful in resolving the keratomycosis.