Erosive polyarthritis in two greyhounds

Clinical signs of disease, treatment, laboratory findings, and gross and microscopic changes of erosive polyarthritis in 2 Greyhounds are described. A microscopic feature that may help distinguish this condition from other types of arthritis is extensive necrosis of deep articular cartilage zones, with relative sparing of the more superficial surface cartilage. We believe that the disease in the 2 dogs of this report was identical to that encountered previously in Britain and Australia. Bacteriologic culture and serologic investigation failed to reveal the causative agent.     

SPONTANEOUS PNEUMOPERITONEUM SUBSEQUENT TO GASTRIC VOLVULUS IN TWO DOGS

In two dogs spontaneous pneumoperitoneum developed following gastric volvulus. The pneumoperitoneum resulted from splenic necrosis and Klebsiella pneumoniae peritonitis in one and from a gastric perforation near the gastroesophageal junction in the other. The first dog was successfully treated by splenectomy, abdominal lavage, and systemic antibiotic therapy; the other was treated by closure of the perforation, tube gastrostomy, abdominal lavage, and systemic antibiotic therapy. One dog was euthanized four weeks after surgery because of metastatic cancer, and the other was euthanized six weeks after surgery due to recurrence of abdominal distention and peritonitis.     

Microscopical studies on the peroxide bleaching of Douglas fir wood

Summary The effect of alkaline hydrogen peroxide on Douglas fir sapwood and heartwood was investigated by ultraviolet microscopy and reflectance spectrophotometry. It was found that the high absorbance of the heartwood elements around 300 nm which was attributed to the flavanone dihydroquercetin was readily eliminated by the action of peroxide. It is also proposed that the brightening effect of hydrogen peroxide is due in part to the destruction of coniferaldehyde groups which occurs to the same extent in both sapwood and heartwood and in all the morphological elements. A correlation between the concentration of chromophoric groups and the concentration of lignin is demonstrated.Paper presented at the Fifth Plenary Meeting of the International Academy of Wood Science in Copenhagen, Denmark, June 17–19, 1976.     

Lamellation in the S2 layer of softwood tracheids as demonstrated by scanning transmission electron microscopy

Summary Ultrathin cross sections of the tracheid wall in black spruce and silver fir have been examined at high resolution by scanning transmission electron microscopy (STEM) and by conventional transmission electron microscopy (TEM). For both softwoods, lamellation of the S2 layer was evident but the lamellae were seen more clearly in the STEM photomicrographs. The interlamellar distance was 7.1 nm in the case of spruce and 8.4 nm for silver fir.     

CONTRAST RHINOGRAPHY IN THE RADIOGRAPHIC EVALUATION OF DISEASES AFFECTING THE NASAL CAVITY, NASOPHARYNX, AND PARANASAL SINUSES IN THE DOG

Positive-contrast rhinography is a simple noninvasive procedure that can be used for radiographic evaluation of the nasal cavity, nasopharynx, and paranasal sinuses in the dog. After assuring the safety of the procedure, it was employed for evaluation of six dogs with nasal and paranasal disease. Contrast rhinography contributed to the identification and assessment of the disease and aided in the diagnosis in dogs where survey radiography was not helpful. This paper proposes the use of positive-contrast rhinography for radiographic evaluation of diseases affecting the nasal cavity, nasopharynx, and paranasal sinuses in the dog.     

Comparative studies on lignin distribution by UV microscopy and bromination combined with EDXA

Summary In order to elucidate a previously reported discrepancy in the ratio of the lignin concentration in the middle lamella to that in the secondary wall as determined by ultraviolet (UV) microscopy and bromination combined with EDXA, the ultraviolet absorptivity of the lignin and the lignin reactivity towards bromination were compared for black spruce wood (Picea mariana Mill.). In addition, UV microscopy and EDXA techniques were applied to the determination of lignin distribution in the tracheids in order to establish the relationship between the two techniques. The results indicated that, although the ultraviolet absorptivity in different morphological regions is essentially the same, the secondary wall lignin was 1.70 times more reactive towards bromination than the middle lamella lignin. By applying the value of 1.70 as a correction to the EDXA results, the estimated lignin distribution by EDXA was in fairly good agreement with that from UV microscopy.The authors would like to thank Dr. J.-F. Revol and Dr. M. Tsuji for their assistance during this study     

Relationship between ball milling and the susceptibility of wood to digestion by cellulase

Summary Aspen wood was ball milled for times as long as 10 days. The change in wood morphology was examined in the ultraviolet microscope. The accessibility of the milled wood to cellulase was also determined. Soon after the commencement of the milling, part of the wood took on a characteristic appearance in which the cell wall material was completely broken down. The proportion of this disordered wall material (DWM) increased with increased time of milling. The accessibility to cellulase increased with the proportion of DWM produced by the milling.The authors wish to acknowledge the interest and valuable advice of Dr. B. A. Pethica throughout the conduct of this research     

Structural studies on the chemical bonds between lignins and carbohydrates in spruce wood

Summary A lignin-carbohydrate material from black spruce (Picea mariana) was treated with a hemicellulase mixture. The carbohydrates in the remaining material were studied by the following methods. a) Treatment with 0.1 M NaOH in the presence of sodium borohydride followed by selective hydrolysis of the furanosidic bonds, b) Smith degradation (periodate oxidation followed by mild acid hydrolysis). The results obtained indicate that lignin is bound to all types of sugar units in the hemicelluloses. For arabino-4-O-methylglucuronoxylan, linkages to the side-chain units seem to dominate. The links to the 4-O-methylglucuronic acid units are ester bonds, probably benzyl ester bonds. Those to the other sugar units in the hemicelluloses are ether bonds, probably benzyl ether bonds. The results suggest, furthermore, that fractions of cellulose are linked to lignin.The authors are indebted to Dr. H. H. Brownell, Ottawa, Canada, for a gift of extracted black spruce wood meal, and to Professor Bengt Lindberg, Stockholm, Sweden, for the use of glc equipment in his laboratory     

Seroprevalence of Borrelia burgdorferi, Anaplasma phagocytophilum, Ehrlichia canis, and Dirofilaria immitis among dogs in Canada

The seropositivity of dogs to Borrelia burgdorferi, Anaplasma phagocytophilum, and Ehrlichia canis antibodies, and Dirofilaria immitis antigen was assessed in Canada. Borrelia burgdorferi had the highest seroprevalence, while that of Dirofilaria immitis has not changed significantly in the past 20 y. The risk for these vector-borne infectious agents in Canadian dogs is low but widespread with foci of higher prevalence.