RADIOGRAPHIC AND COMPUTED TOMOGRAPHIC CHANGES AND CLINICAL PRESENTATION OF SPIROCERCOSIS IN THE DOG

A retrospective study of 39 dogs with spirocercosis is described, emphasizing radiographic and computed tomographic aspects and clinical presentation. Dogs were classified as complicated or uncomplicated, both clinically and radiographically. Besides the expected upper gastrointestinal signs, a high incidence of respiratory (77%) and locomotor (23%) complications were present. All dogs had thoracic radiographs. Esophageal masses were radiographically classified as typical or atypical according to their location. Twenty-seven dogs had a typical caudal esophageal mass. Six dogs had a mass atypically located in the hilar region. These masses were smaller and more difficult to visualize radiographically. The remaining 6 dogs did not have a radiographically detectable esophageal mass. Radiology as an initial diagnostic tool was effective in detecting and localizing the mass and to detect early respiratory abnormalities such as pleuritis, mediastinitis, pneumonia, and bronchial displacement. Endoscopy was the modality of choice to confirm antemortem esophageal masses. In dogs where the mass filled the whole esophageal lumen, endoscopy failed to give essential information necessary for surgical excision of neoplastic masses, such as the extent of esophageal wall attachment. Caudal esophageal sphincter involvement was difficult to determine endoscopically with large caudal esophageal masses. Computed tomography was performed on 3 dogs and did not address the latter problems completely, but was found to be a sensitive tool to detect focal aortic mineralization and early spondylitis, both typical for the disease, and essential in the diagnosis of non- or extramural esophageal abnormalities.     

Effect of serotonergic afferents on quantal release at central inhibitory synapses

Although most examples of modulation of synaptic transmission have been obtained from excitatory rather than from inhibitory connections, serotonin (5HT) is now shown to cause a presynaptic facilitation of release of the inhibitory neurotransmitter glycine. Brief local injections of this amine, or application of a 5HT uptake blocker, produce a long-lasting enhancement of both spontaneous and evoked inhibitory currents in the teleost Mauthner cell. Quantal analysis showed that the probability of release is increased. Focal recording indicated that 5HT acts directly on the inhibitory terminals, possibly reducing potassium conductances. Double staining with specific antibodies demonstrated a morphological substrate for this effect. Nerve endings that contain 5HT contact inhibitory terminals directly apposed to postsynaptic glycine receptors.     

Influence of Land-Surface Evapotranspiration on the Earth's Climate

Calculations with a numerical model of the atmosphere show that the global fields of rainfall, temperature, and motion strongly depend on the land- surface evapotranspiration. This confirms the long-held idea that the surface vegetation, which produces the evapotransporation, is an important factor in the earth's climate.     

Evaluation of selected growth factor expression in canine spirocercosis (Spirocerca lupi)-associated non-neoplastic nodules and sarcomas

The study aims to assess the expression of vascular endothelial growth factor (VEGF)-A, fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF) in the progression of the spirocercosis-induced oesophageal nodule in the dog from early, non-neoplastic, inflammatory nodule to sarcomatous neoplasia. Triplicate 4 μm-thick sections from 62 paraffin blocks containing Spirocerca-induced nodules were treated according to the steptavidin-biotin (LSAB) immunohistochemical method using polyclonal goat-anti-canine VEGF and anti-human FGF and PDGF antibodies. The nodules were classified as early inflammatory (n=15), pre-neoplastic (n=27) and neoplastic (n=20). Additionally, 10 sections of normal distal third of the oesophagus and 21 non-spirocercosis-related sarcomas were evaluated and compared with the Spirocerca-induced nodules. Five non-overlapping high power fields per case were evaluated under the light microscope and the fibroblasts were evaluated for percentage of labelled cells. The intensity of labelling was further classified as weak (score 1) or strong (score 2). The intensity score was multiplied by the percentage of labelled fibroblasts to yield a field score and the final score was obtained by calculating an average of the five fields. Antigen labelling was compared between the different histological grades and the controls using the Kruskal-Wallis test followed by the Mann-Whitney test for comparison between specific groups. The level of significance was set at 0.05. There were significant differences between the groups' score in all the growth factors that were examined. The normal oesophagus showed no labelling for any of the growth factors. FGF scored highest in the non-spirocercosis-related sarcoma group (median 118, 3-194) followed by the spirocercosis-induced sarcoma (34.5, 0-138), pre-neoplastic nodule (8, 0-99) and early nodule (0, 0-30) groups. All the differences among the groups were significant. VEGF scored highest in the non-spirocercosis-related sarcoma group (median 47, 1-110) followed by the spirocercosis-induced sarcoma (26, 0-136), pre-neoplastic nodule (0, 0-62) and early nodule (0, 0-35) groups. PDGF scored highest in the non-spirocercosis-related sarcoma group (median 29.2, 0-70) followed by the pre-neoplastic nodule (23.4, 0-95), early nodule (13.6, 0-132) and spirocercosis-induced sarcoma (0, 0-47) groups. The expression of VEGF and FGF increased as the nodule progressed from early inflammation to sarcoma, but it was not limited to spirocercosis-induced sarcomas. The expression of PDGF in spirocercosis was restricted to the early stages of nodule progression. Further investigation is warranted to establish whether FGF, VEGF or PDGF play a role in the pathogenesis of the malignant transformation in canine spirocercosis or are they simply integral to angiogenesis induction?     

Curvilinear, three-dimensional motion of chromatin domains and nucleoli in neuronal interphase nuclei

The term "nuclear rotation" refers to a motion of nucleoli within interphase nuclei of several cell types. No mechanism or function has been ascribed to this phenomenon, and it was unknown whether nuclear structures in addition to nucleoli participate in this motion. Moreover, it was unclear whether nuclear rotation occurs independent of concurrent motion of juxtanuclear cytoplasm. The work reported here presents quantitative evidence, for three-dimensional intranuclear, tandem motion of fluorescently labeled chromatin domains associated with nucleoli and those remote from nucleoli. The results show that such motion is curvilinear, that it is not restricted to nucleoli, and, moreover, that it occurs independently of motion of juxtanuclear, cytoplasmic structures. These results suggest that this motion represents karyoplasmic streaming and its function is to transpose to nuclear pores those chromatin domains actively transcribed.     

"Intrinsic" immunological tolerance in allophenic mice

Mice experimentally derived from pairs of conjoined, undifferentiated, cleavage-stage embryos of different histocompatibility genotypes can retain cells of each strain, which still produce their characteristic antigenic products. The animals are permanently tolerant of cells of both original types, remain free of runt disease, and display a normal and specific immune response to introduction of a foreign antigen. Absence of autoimmunity in development of ordinary animals is explainable by the "intrinsic" kind of tolerance found here.     

Human beta-globin gene sequences injected into mouse eggs, retained in adults, and transmitted to progeny

Foreign gene sequences were retained in two adult mice (out of 62 analyzed) from fertilized eggs injected with a recombinant plasmid containing the human beta-globin genomic region and the herpes simplex viral thymidine kinase gene. The intact human and viral genes were found in DNA of one of the animals and, in the other, at least part of the human globin gene was present. The latter individual transmitted these sequences to its progeny in a Mendelian ration. Thus, human DNA may be incorporated into the germ line of mice for in vivo studies of regulation of gene expression in development, genetic diseases, and malignancy.     

Seminal vesicle formation and specific male protein secretion by female cells in allophenic mice

The relation of cellular sex genotype to phenotype was examined in seminal vesicles of adult allophenic mice with cellular sex chromosome mosaicism. Each animal originated from conjoined blastomeres of an embryo of female (XX) and one of male (XY) constitution, from different inbred strains. Cells of both sexes were detected in bone marrow and certain other somatic tissues; cellular sex of seminal vesicles was deduced from strain-associated electrophoretic variants of proteins coded for at autosomal loci. Seminal vesicles composed partly or entirely of female cells were found in male and pseudohermaphrodite individuals. In a pseudohermaphrodite, both allelic variants of the tissue-specific normal male seminal vesicle protein (Svp-locus) were present, signifying that female as well as male cells were synthesizing the protein. Male-determining factors on the Y chromosome are thus not required in cells that differentiate into functional seminal vesicles.     

Congenital narrowing of the intrapharyngeal opening in a dog with concurrent oesophageal hiatal hernia

A one-year-old, male, smooth-haired standard dachshund was presented with a history of chronic hypersalivation, dysphagia, puffing of the cheeks on expiration, and inspiratory stridor. Oral examination revealed a moderately thickened tongue radix and that the normal intrapharyngeal opening was obliterated. A 7 mm long, midline palatal slit was the only communication between the naso- and oropharynx. The soft palate was fused to the caudal pharyngeal wall. A concurrent hiatal hernia was diagnosed on thoracic radiographs. The soft palate abnormality was surgically corrected and the hiatal hernia was managed medically. On follow-up evaluations, the clinical signs had markedly improved, and the hiatal hernia was no longer visible on survey thoracic radiographs.