Subcellular distribution of malathion,phenthoate, and diethylsuccinate carboxylesterases in rat lungs

The subcellular distribution of malathion, phenthoate, and diethylsuccinate carboxylesterases was determined in the lungs of male Sprague-Dawley rats and in rats administered lung toxic doses of bromobenzene and paraquat. In control with the former two substrates, the highest activity was encountered in the 6500g and 12,000g pellets. In addition, significant activity was found in the 100,000g supernatant. These fractions hydrolyzed diethylsuccinate very slowly, and the major diethylsuccinate carboxylesterase activity was recovered in the 100,000g pellet. The bromobenzene treatment had no effect on these carboxylesterases; however, the paraquat treatment significantly decreased the phenthoate and diethylsuccinate carboxylesterases in the 100,000g pellet without altering the activity in the other fractions. The present study suggested that the subcellular distribution of malathion and phenthoate carboxylesterases is different from that in liver. The present study revealed that, in the lungs, the highest total activity for malathion and phenthoate carboxylesterases was found in the 100,000g supernatant, in comparison with liver, where the 100,000g pellet contains a much higher activity of these enzymes. The decrease in specific activities of diethylsuccinate and phenthoate carboxylesterases following the treatment with a pneumotoxicant may serve as an indicator of lung damage.     

Non-invasive determination of heart rate in newly hatched chicks.

1. Using a flexible piezoelectric probe, we detected non-invasively the cardiogenic precordial movements of domestic fowl chicks and measured heart rate (HR) daily over the first week after hatching (day 0) for comparison with previously measured embryonic HR. 2. HR of the hatchlings was much more variable than embryonic HR. The mean HR at a given age also varied among the 5 chicks measured. 3. The overall mean HR was 280 +/- 20 (SD, n = 5) bpm on day 0. This value was similar to the prepipping HR and lower than that of externally pipped embryos. It increased to 342 +/- 39 bpm 3 days later.     

Chitin synthase 1 (Chs1) gene sequences of Microsporum equinum and Trichophyton equinum

Chitin synthase 1 (Chs1) genes from Microsporum equinum and Trichophyton equinum were compared with those of the other dermatophytes. The Chs1 nucleotide sequences of these dermatophytes from horses showed more than 80% similarity to those of Arthroderma benhamiae, A. fulvum, A. grubyi, A. gypseum, A. incruvatum, A. otae, A. simii, A. vanbreuseghemii, Epidermophyton floccosum, T. mentagrophytes var. interdigitale (T. interdigitale), T. rubrum and T. violaceum. Especially high degree of nucleotide sequence similarity of more than 99% was noted between the Chs1 gene fragments of M. equinum and A. otae, and those of T. equinum, T. interdigitale and A. vanbreuseghemii, respectively. The phylogenetic analysis of their sequences revealed that M. equinum was genetically very close to A. otae and T. equinum to A. vanbreuseghemii. A molecular analysis of Chs1 genes will provide useful information for the genetic relatedness of M. equinum and T. equinum and confirm the value of DNA sequencing in identification of these two dermatophytes.     

Nine cases of granular cell tumors in B6C3F1 mice

The histological characteristics of 9 cases of granular cell tumors (GCTs) observed in B6C3F1 mice were examined to determine their cellular origin. Seven of the 9 cases were found in the uterus and other 2 cases were in the subcutaneous tissue. Tumor cells had abundant granules in the cytoplasm which were stained with PAS and were resistant to diastase treatment. Ultrastructurally, the granules were identified as lysosomes. The cell surface had cytoplasmic processus showing interdigitation with adjacent cells. A character feature of the tumor cells was the presence of a desmosome-like structure on their cell surface but no basal lamina was demonstrated. Although GCTs have been considered to be derived from Schwann cells on the basis of their ultrastructural features and S-100 protein-immunopositive findings, the absence of basal lamina in the present cases may raise a controversy as to their origin.     

Decreased apoptotic polymorphonuclear leukocyte rate in dogs with pyometra

Polymorphonuclear neutrophil (PMN) apoptosis was examined in three dogs with pyometra by TUNEL assay in a 24-hr incubation period and compared with that in healthy control dogs (n=5). The incidence of apoptotic PMNs in dogs with pyometra was 26.4 +/- 5% and that in healthy dogs was 54.3 +/- 7%. The results indicated that apoptotic PMN rates in dogs with pyometra were significantly lower than those in control dogs (p<0.05), suggesting the prolongation of PMN survival.     

Molecular cloning of canine thrombomodulin cDNA and expression in normal tissues

Thrombomodulin (TM) is a glycoprotein localized mainly on endothelial cell surfaces, and is a major regulator of vascular thromboresistance. The entire open reading frame of canine TM cDNA comprises 1737 bp, encoding 578 amino acid residues. Comparison of the deduced amino acid sequence from canine TM with those of human, mouse, rat, rabbit and bovine (partial) TM sequences revealed 73.1%, 69.1%, 65.8%, 74.3% and 69.5% identity, respectively. Canine TM mRNA expression was confirmed by RT-PCR analysis in lung, liver, spleen, kidney, pancreas and lymph node, and was relatively low in heart, cerebrum, urinary bladder and uterus. The present results provide valuable data for research into canine coagulation disorders.     

Positive reactions to common allergens in 42 atopic dogs in Japan

Clinically important allergens for the diagnosis and treatment of atopic dermatitis vary geographically. In order to identify the most prevalent allergens in atopic dogs in Japan, 42 dogs with a clinical diagnosis of atopy were tested using both in vivo (intradermal skin test (IDST)) and in vitro (antigen-specific IgE assay) allergy tests. Allergens used for IDST included 26 allergen extracts from eight allergen groups: trees, weeds, grasses, house dust mites (HDM), molds, foods, epithelia, and arthropods. Immunodot assay was used to measure antigen-specific IgE against 24 allergens from these eight groups and against fish such as cod and sole. In the 42 dogs, the most common positive allergen reaction was to HDM on both IDST (29/42 dogs or 69%) and in vitro testing (23/42 or 54.8%). The second most frequent positive allergen reaction was to Japanese cedar pollen (21/42 or 50.0% for IDST and 7/42 or 16.7% for in vitro testing). In both tests, less than 20% of dogs had positive reactions to molds or foods. Positive reactions to cat epithelia were frequently found on IDST, but rarely found on in vitro testing. Agreement between the two tests was found in 26 instances: HDM (21 dogs), Japanese cedar pollen (five dogs) and wheat (one dog). In this study, the two most common allergens involved in atopic dermatitis in dogs in Japan were HDM and Japanese cedar pollen.