Computed tomography of testicular torsion in a juvenile dog with unilateral cryptorchidism

A 14-week-old male unilaterally cryptorchid Clumber spaniel was presented for acute lethargy. Physical examination revealed abdominal pain, and a single testis was palpated in the scrotum. Abdominal ultrasound and computed tomography (CT) revealed a poorly vascularized, ovoid structure immediately caudal to the left kidney with scant regional peritoneal effusion. Left intra-abdominal testicular torsion was confirmed at surgery, and routine cryptorchidectomy was performed. The patient recovered uneventfully from anesthesia and surgery.Key clinical message:The most common CT characteristics of testicular torsion were present in this case and correlated well with sonographic findings to allow for rapid, accurate diagnosis and surgical planning of unilateral, non-neoplastic, intra-abdominal cryptorchid testicular torsion in a juvenile dog. Contrast enhanced CT facilitated accurate localization of the undescended testis and evaluation of testicular perfusion and may be a useful alternative to ultrasound for diagnosing testicular torsion, especially in indeterminate cases.     

Effects of ammonium and inorganic carbon enrichment on growth and yield of a hydroponic tomato crop

Effects of varying the proportions of NO₃^— and NH₄⁺ in the growth medium on seedling growth and tomato fruit yield (Lycopersicon esculentum L. cv. Trust F1) were investigated in greenhouse hydroponic experiments. The presence of NH₄⁺ as the sole N source (11 mM) was toxic: it curtailed growth and decreased chlorophyll content of the leaves. However, at low concentration (10 % of total N), the presence of NH₄⁺, with or without added dissolved inorganic carbon (DIC), increased vegetative growth and fruit yield by ˜ 15 %, and enhanced taste/flavor of the fruits. In DIC‐enriched treatment, pH was maintained at 5.8 by addition of KHCO₃ or as CaCO₃. The presence of NH₄⁺, at 10 % of total N, inhibited NO₃^— uptake rates by ˜ 27 %. The rates of uptake of NO₃^— and NH₄⁺ were comparable (13.3 and 14.2 mmol plant^—1 d^—1, respectively, in the presence of DIC, and 14.7 and 14.0 mmol plant^—1 d^—1, respectively, in the absence of DIC), despite such a large difference in their concentrations in the nutrient feed solution. A higher proportion of NH₄⁺ (up to 50 % of total N) had no further significant effect upon early vegetative growth, but in a long‐term experiment resulted in a high incidence of blossom end‐rot (BER) disease, thereby severely curtailing fruit yield. The presence of even 1.1 mM NH₄⁺ reduced Ca²⁺ and Mg²⁺ accumulation in the leaves as well as in fruits.     

A statistical study of seven curves for describing the sorption of phosphate by soil

Seven mathematical models, which have been advanced for describing phosphate sorption by soils, are studied here with respect to their statistical behaviour in estimation. These seven non-linear regression models include the Langmuir equation and two extensions of it, the Freundlich equation and two extensions of it, and Gunary's equation. Measures of non-linear behaviour, such as the Bates & Watts (1980) curvature measure of intrinsic non-linearity and the Lowry & Morton (1983) asymmetry measure of non-linearity, were calculated for each model in combination with each of six data sets. It was found that the Freundlich equation and the extension of it proposed by Sibbesen behaved best, with Gunary's equation also having acceptable statistical properties, whereas the Langmuir equation and its extensions behaved worse, exhibiting properties which indicate that the estimators of their parameters would be severely biased and non-normal in distribution. It is believed that similar conclusions may apply to other processes involving surface adsorption.     

Measurement of glycosaminoglycans and keratan sulphate in canine arthropathies

Glycosaminoglycans (gag) and keratan sulphate (ks) were measured in sera and synovial fluids from dogs with either osteoarthritis (oa) or rupture of the cranial cruciate ligament (ccl) and normal dogs. The dogs with oa had higher synovial fluid gag levels (P<0·002) and serum KS (P<0·03) compared to the normal dogs. No significant differences in serum gag were found in either group. In both oa and rupture of the ccl, gag levels were increased in the synovial fluid from the affected joint compared with the clinically normal (inactive) contralateral joint. Neither gag nor ks measurements correlated with serum and synovial fluid antibodies to collagen type II, synovial fluid white cell count or age of dog. It is unlikely that the measurement of these cartilage breakdown products is of value for diagnostic or prognostic use in canine arthropathies.     

Inheritance and reliability of random amplified polymorphic DNA-markers in two consecutive generations of common carp (Cyprinus carpio L.)

Random amplified polymorphic DNA (RAPD) markers have been used in a variety of genetic studies in fisheries and aquaculture. Most population studies are performed without preliminary data demonstrating the Mendelian inheritance and reproducibility of RAPD markers. In this study, the inheritance and reproducibility of RAPD markers was examined in two consecutive generations of common carp, Cyprinus carpio L. Variability and segregation of RAPD markers were investigated in one F₁ progeny and three F₂ progenies. Seventy-four RAPD markers were generated by five primers using DNA extracted from the initial ornamental (koi) common carp female and wild-type colour common carp male. Fifty-five of these RAPD markers were transmitted to the F₁ progeny and the inheritance patterns were analysed. Twenty RAPD markers were fully reproducible and demonstrated dominant simple Mendelian inheritance patterns in two consecutive generations. Twenty-four RAPD markers were not reproducible in all progenies. Thirteen markers displayed inheritance ratios in the progenies that did not fit simple Mendelian inheritance patterns. Non-reproducibility of RAPD markers and distorted ratios may be caused by the absence of amplification, poor amplification or by the appearance of artefact bands. Random amplified polymorphic DNA markers with poor reproducibility and non-Mendelian inheritance can lead to misinterpretations of data in population studies, resulting in errors in the estimation of genetic diversity within and between individual populations. Therefore, it is recommended to first identify the set of reproducible RAPD markers that demonstrate Mendelian inheritance before application of the RAPD technique in population studies.     

Regulation of urease production in soil by microbial assimilation of nitrogen

Summary Studies of the effects of different forms of N on urease production in soils amended with organic C showed that although microbial activity, as measured by CO₂ production, was stimulated by the addition of NH₄ ⁺ or NO₃ ^- to C-amended soils (200 mol glucose-C g^–1 soil), urease production was repressed by these forms of N. The addition of L-methionine sulfoximine, an inhibitor of inorganic N assimilation by microorganisms, relieved the NH₄ ⁺ and NO₃ ^- repression of urease production in C-amended soil. The addition of sodium chlorate, an inhibitor of NO₃ ^- reduction to NH₄ ⁺ by microorganisms, relieved the NO₃ ^- repression of urease production, but did not eliminate the repression associated with NH₄ ⁺. These observations indicate that microbial production of urease in C-amended soils is not directly repressed by NH₄ ⁺ or NO₃ ^-, but by products formed by microbial assimilation of these forms of N. This conclusion is supported by our finding that the biologically active L-isomers of alanine, arginine, asparagine, aspartate, and glutamine, repressed urease production in C-amended soil, whereas the D-isomers of these amino acids had little or no influence on urease production. This work suggests that urease synthesis by soil microorganisms is controlled by the global N regulon.