The Kinetics of Hematopoiesis in the Light Horse I. The Lifespan of Peripheral Blood Cells in the Normal Horse

Three Standardbred horses were given 0.2 mg (1 mCi) of ⁷⁵selenomethionine intravenously and a second group of three were given 10 mCi of tritiated diisopropylfluorophosphate (0.5 mg) intravenously. Observations on labeled cells were continued for 250 days after radioselenium injection and 160 days after tritium injection.

The lifespan of erythrocytes using ⁷⁵selenmethionine was 155 ± 10 days and 148 ± 7.8 days using tritiated diisopropylfluorophosphate. There was no significant difference at the 10% level between the lifespans, using these labels. The uptake of radioselenium into erythrocytes reached a mean maximum of 11.5% at 82 ± 18.9 days after injection of the label. There was an elution of from 17.6% of the injected dose of tritium label down to 7.5% eight days after injection of this isotope. From this study both of these labels appear to be satisfactory for determining the erythrocyte lifespan of the horse.

The mean time of the curve of mean radioselenium activity of peripheral blood leukocytes for the three horses was 5.54 days and the lifespan of these cells was seven days. The mean lifespan of peripheral blood leukocytes of the three horses after in vivo labelling with tritiated diisopropylfluorophosphate was 17.3 hours. No specific labelling was found in bone marrow or peripheral blood cells at this level of tritium labelling by dipping emulsion autoradiography.

The mean lifespan of equine platelets for three horses using radioselenomethionine was 9.2 days and the mean lifespan of equine platelets using tritiated diisopropylfluorophosphate was 6.6 days in a group of three horses.

     

Hyperbilirubinemia in sick cattle.

Hyperbilirubinemia was present in 387 out of 1279 sick cattle admitted to the clinic of the Ontario Veterinary College. One hundred and ninety five of these had a total serum bilirubin of 17 mumol/L or greater. Clinical records, laboratory data and when available, pathology reports from these 195 animals were examined in an attempt to explain the reason for the high bilirubin levels. The hyperbilirubinemia in 187 of these was mainly due to an increase in unconjugated bilirubin. Jaundice, liver disease or anemia was not a feature and alkaline phosphatase was not elevated. The 195 animals with hyperbilirubinemia suffered from a variety of diseases that seemingly were unrelated to the increased bilirubin. The most frequently described signs were anorexia and rumen stasis. Liver disease was diagnosed in eight animals and in these clinical jaundice, and increased conjugated bilirubin and alkaline phosphatase was a feature. It was concluded that hyperbilirubinemia occurred in many diseases of cattle and in most instances was related to a failure of the liver to remove unconjugated bilirubin from the serum rather than to a failure of the liver to excrete conjugated bilirubin.     

A computer-derived protocol to aid in selecting medical versus surgical treatment of horses with abdominal pain

In order to determine which variables are useful in identifying horses with abdominal pain requiring surgery, data were analysed from 219 horses presented at one veterinary teaching hospital. Using multiple stepwise discriminant analysis with a recursive partitioning algorithm, we obtained a decision tree that identifies surgical and non-surgical patients. The prevalence of surgical patients was 79 per cent in this population. The sensitivity, specificity, and positive and negative predictive values of this decision tree were 99 per cent, 55 per cent, 90 per cent and 99 per cent respectively. Compared to the clinical decision, this decision tree yielded more false positives (11 per cent) but almost eliminated false negatives (1 per cent). This decision tree was validated by the jack-knife method and also by evaluation using a new sample in a second veterinary teaching hospital in which the prevalence of surgical patients was 55 per cent. This led to sensitivity, specificity and positive and negative predictive values of 93 per cent, 73 per cent, 81 per cent and 89 per cent respectively.     

Fungi isolated from bovine udders,and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources.

METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi.

RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats.

CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi.

CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance.     

Subepiglottic cysts in 15 horses

Subepiglottic cysts (SECs) are an infrequent cause of upper respiratory tract noise and exercise intolerance in horses. They may also be associated with no clinical signs and be an incidental finding during routine upper airway endoscopy. The aim of this study was to assess the effect on performance of horses undergoing surgical removal of SECs. The case records of 15 horses (1995–2009) diagnosed with SECs were retrieved. Eleven (73%) of the 15 horses included in the study were Thoroughbred racehorses. Eleven (73%) of the 15 horses had no preoperative clinical signs related to the SECs, with the remaining 4 (27%) having a respiratory noise (n = 4), nasal discharge (n = 1), difficulty swallowing (n = 1) or a cough (n = 1). Endoscopic examination in the standing horse was diagnostic in 93% (n = 14) of horses. Nine (82%) of the 11 Thoroughbred horses were yearlings, of which only one horse (11%) presented with clinical signs consisting of a respiratory noise and nasal discharge. Four of the 11 (36%) Thoroughbred horses were found to have concurrent epiglottic entrapment. Surgical removal was successful in all cases. Eight of the 11 (73%) Thoroughbred horses in this study raced following SEC removal. The majority of SECs are identified during routine endoscopic examinations and are not associated with clinical signs. The prognosis following surgical removal of SECs is good and future performance does not appear to be affected.     

A case of "watery mouth" in a New Zealand Romney lamb

Watery mouth was diagnosed as the cause of illness and subsequent death in a 3-day-old Romney lamb which had not received early colostrum. The history, clinical signs and post-mortem findings were typical of the disease as seen in other countries, including Great Britain. The diagnosis was based on the clinical signs and was supported by an absence of post-mortem findings of other specific neonatal diseases. The potential importance of watery mouth under conditions of intensive husbandry in New Zealand is discussed.     

Synthesis of large arrays of well-aligned carbon nanotubes on glass

Free-standing aligned carbon nanotubes have previously been grown above 700 degreesC on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666 degreesC by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas was used as the carbon source and ammonia gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0. 1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication.     

Localization of metastable atom beams with optical standing waves: nanolithography at the heisenberg limit

The spatially dependent de-excitation of a beam of metastable argon atoms, traveling through an optical standing wave, produced a periodic array of localized metastable atoms with position and momentum spreads approaching the limit stated by the Heisenberg uncertainty principle. Silicon and silicon dioxide substrates placed in the path of the atom beam were patterned by the metastable atoms. The de-excitation of metastable atoms upon collision with the surface promoted the deposition of a carbonaceous film from a vapor-phase hydrocarbon precursor. The resulting patterns were imaged both directly and after chemical etching. Thus, quantum-mechanical steady-state atom distributions can be used for sub-0.1-micrometer lithography.     

An approximately 15,000-year record of El Nino-driven alluviation in southwestern ecuador

Debris flows have deposited inorganic laminae in an alpine lake that is 75 kilometers east of the Pacific Ocean, in Ecuador. These storm-induced events were dated by radiocarbon, and the age of laminae that are less than 200 years old matches the historic record of El Nino events. From about 15,000 to about 7000 calendar years before the present, the periodicity of clastic deposition is greater than or equal to 15 years; thereafter, there is a progressive increase in frequency to periodicities of 2 to 8.5 years. This is the modern El Nino periodicity, which was established about 5000 calendar years before the present. This may reflect the onset of a steeper zonal sea surface temperature gradient, which was driven by enhanced trade winds.