Excess iodide and the accumulation of 125i by the thyroid,plasma and developing oocytes of the Japanese quail 1

1. Developing oocytes of the Japanese quail accumulated 0.lb44 μg of each 1 μg of 125I‐labelled iodide after intra‐muscular injection of doses up to 500 μg iodide as Nal but only 0.lb007 μg after injection of more than this: the abrupt change in the rate of accumulation was attributed to saturation of the iodide transport mechanism.

2. The proportion of available iodide transferred into the oocytes appeared to be more dependent on the amount of iodide injected and the total weight of growing oocytes than on a requirement for either a store of iodide for the embryo or an iodide excretory pathway for the hen.

3. The thyroid was about four times more active in accumulating iodide than the oocyte.

4. The percentage of iodide accumulated by the plasma was the same at all dose rates.     

Ovarian iodide uptake and triiodothyronine generation in follicular fluid. The enigma of the thyroid ovary interaction

Since 1928, the iodine concentration in the ovary has been known to be higher than in every other organs except the thyroid. The ovarian iodide uptake varies with sexual activities, is enhanced by estrogens and a hypothyroid state and blocked by goitrogens. The recent discovery of a sodium iodide symporter (NIS) in ovaries has offered a possible mechanism for ovarian iodide uptake and other functional similarities to its thyroid counterpart. Nevertheless, the physiological significance of ovarian iodine uptake and accumulation remains unknown. The presence of thyroid hormones (TH) in follicular fluid (FF) has been established recently. Our preliminary studies on TH in FF (1996-1998) in rabbits, pigs, horses showed that the concentration of T4 is generally lower than that in serum and that for T3 is within the normal range or higher. A positive correlation exists between the T4 levels in FF and serum but not between the corresponding T3 levels. These studies revealed, for the first time, the presence of the ovarian 5'-monodeiodinase system in FF capable of generating T3 (ovary-born T3) by outer ring deiodination of T4. In mares, seasonal polyestrus, ovarian 5'-monodeiodinase (MD) activity and FF T3 levels have been found to be higher during the ovulatory period than in the anovulatory one. The exact physiological significance of this system generating T3 and coexisting with isoforms of TH receptors in granulosa cells has not been elucidated. A direct role of T3 for the early follicular development, differentiation and for the steroidogenic capability of granulosa cells, although strongly suggested by data obtained from in vitro studies, has to be elucidated.     

Bovine monoclonal antibodies to the F5 (K99) pilus antigen of E. coli, produced by murine/bovine hybridomas

Lymph node cells from calves immunized with purified pilus antigen of K99+ enterotoxigenic E. coli (ETEC) were fused with mouse myeloma (NSO) cells, and with non-Ig producing mouse/calf hybridomas or with a bovine Ig-producing mouse/calf/calf secondary hybridoma. Lines secreting bovine monoclonal IgG1 specific for K99 pilus antigen in an ELISA were obtained in each case. The two lines derived from xenohybridoma fusion partners have been secreting anti-K99 bovine monoclonal antibody for over one year in continual passage. None of the antibodies cross-reacted with other pilus types including K88, CFAI, CFAII, 987P or CP; they all inhibited agglutination of horse RBC (which have a K99 receptor) in the presence of K99 antigen; they showed positive fluorescence in an indirect binding assay on K99+ ETEC and inhibited K99+ ETEC adhesion to piglet enterocytes. These antibodies have potential prophylactic and therapeutic use in control and treatment of diarrhoea.     

Modification by 6-hydroxydopamine (6-OHDA) of the inhibition of extrinsic rumen contractions in sheep produced by beta-endorphin

In sheep, beta-endorphin (1 and 2 micrograms/kg) administered into the third cerebral ventricle caused a significant inhibition of the frequency of rumen contractions. The amplitude of the first rumen contractions, following immediately after the end of infusion, and the average amplitude of primary rumen contractions, were inhibited. Beta-endorphin caused general psychomotor excitability. These results suggest that an inhibitory mu and delta opioid system is involved in the control of forestomach motility and general behaviour in sheep. All effects of beta-endorphin were completely prevented by i.c.v. 6-hydroxydopamine (6-OHDA, 18.2 micrograms/kg) pre-treatment. These results suggest that beta-endorphin-induced inhibition of rumen motility is due to central noradrenergic system activation. The exact location of this noradrenergic system remains to be determined.     

Effect of recombinant human TSH on the uptake of radioactive iodine (I) by the thyroid gland in healthy beagles

In human medicine, recombinant human thyroid-stimulating hormone (rhTSH) increases thyroid radioactive iodine uptake (RAIU), allowing radioiodine-131 (¹³¹I) dose reduction and greater efficacy in the treatment of differentiated thyroid cancer and multinodular goiter. The goal of this study was to evaluate the effect of rhTSH, administered 24 h and 48 h before radioiodine-123 (¹²³I), on the thyroid RAIU in healthy dogs. Seven healthy euthyroid beagles were randomly allocated to 3 groups (2 groups of 2 dogs and 1 group of 3 dogs) in a prospective, blinded, crossover study. At Week 1, 1 group received ¹²³I for a baseline RAIU; 1 group received 100 μg of rhTSH IV 24 h before ¹²³I, and 1 group received 100 μg of rhTSH IV 48 h before ¹²³I. All dogs received 37 MBq of radioactive ¹²³I IV, and thyroid RAIU was determined 8 h, 24 h, and 48 h thereafter. The study was designed in such a manner that each dog received the 3 treatments and a wash-out period of 3 wk was respected in between. Blood samples were taken for measurement of serum total thyroxine (TT4) and thyrotropin (TSH) concentrations at baseline and 6 h, 12 h, 24 h, and 48 h after rhTSH administration. Recombinant human TSH caused no significant change on thyroid RAIU. The overall mean thyroid RAIU significantly decreased during the study independent of the treatment. Recombinant human TSH significantly increased serum TT4 concentration, which peaked 6 h after rhTSH administration. Compared to baseline, serum TSH concentration remained higher at 6 h, 12 h, 24 h, and 48 h. However, a statistically significant difference was reached only at 6 h and 12 h after rhTSH administration. No adverse effects of rhTSH were observed during the study. Further studies are needed to determine the best timing and dosage of administration of rhTSH in healthy and thyroid carcinoma dogs.     

Dicoumarol as the cause of abortion in mink (author's transl)

The use of discoumarol for causing abortion in mink is discussed. D icoumarol affects the coagulation mechanism of the blood. Coumarol derivatives are very similar to the Vitamin-K complex and are assimilated into the enzyme system in the place of Vitamin-K, inactivating the enzyme system. Depending on dosage, dicoumarol can serve as a poison, an anticoagulant, or a means of inducing abortion. In an experiment involving 15 mink, it was found that .2-.6 mg. of dicoumarol/kg of body weight, given through an 8-10 day period resulted in abortion. Doses of 1.2-1.3 mg/kg of body weight given through a 4-6 day period can cause fatal hemorrhaging.     

Status of the 1805 strain of Mycoplasma iowae (K component of serovar I,J,K, N,Q,R) and the SA strain of M. gallopavonis (serovar F)

Contrary to historical evidence, recent biochemical and serological studies have suggested that the 1805 strain of M. iowae (K component of serovar I,J,K,N, Q,R) and the SA strain of M. gallopavonis (serovar F) were members of the species M. gallinaceum. After examining three seeds of strain 1805 and an original seed of the SA strain, we present evidence to indicate that 1805 and SA are indeed valid members of the species M. iowae and M. gallopavonis, respectively. However, some seeds of strains 1805 and SA may contain M. gallinaceum. In the case of strain 1805, it is possible that the original seed may have contained M. gallinaceum.     

Enteritis as a cause of mortality in the western bluebird (Sialia mexicana)

Increased mortalities in adult western bluebirds utilizing nestboxes were noted in western Oregon during 1998 and 1999. A necrohemorrhagic enteritis was found in 8 of 10 birds submitted for necropsy. Acanthocephalan parasites were present in four of eight birds with enteritis. Microscopic changes consistent with necrotic or ulcerative enteritis were commonly present. Anaerobic culture of the intestine yielded Clostridium perfringens in three of three birds. Genotype analysis of two of these isolates revealed them to be C. perfringens type A. Bacterial enteritis is believed to be the cause of the increased mortality rate, but further investigation is required to prove a definitive link to a clostridial agent.     

Prevalence and macro- and microscopic lesions produced by Gasterophilus nasalis (Diptera: Oestridae) in the Botucatu Region, SP, Brazil.

The objective of the present study was to investigate the prevalence of Gasterophilus nasalis larvae in Botucatu, the central west region of S?o Paulo State, Brazil, and to describe the lesions caused by the parasite. The climate of Botucatu is warm and rainy during the months of December through March and cool and dry during the months of May through August. The prevalence of G. nasalis was 16.84%, and the period of peak infestation corresponded to the months of cold and dry weather. The lesions detected at the sites of larval attachment were examined macro- and microscopically. Erosions and ulcerations of the gastric mucosa and proximal duodenum were the major macroscopic lesions detected. Microscopically, the lesion spectrum ranged from mild inflammatory reactions to extensive necrosis and ulceration.     

Characterization of the renal portal system of the common green iguana (Iguana iguana) by digital subtraction imaging.

Digital subtraction angiography was used to map the venous blood flow from the pelvic limb and the tail in the common green iguana (Iguana iguana). The majority of blood returning from the pelvic limb bypassed the kidney and entered the general circulation, whereas venous blood flow from the tail entered the renal portal circulation. No evidence was found of a renal portal valve.     

Genotypic prevalence of the fimbrial adhesins (F4, F5, F6, F41 and F18) and toxins (LT, STa, STb and STx2e) in Escherichia coli isolated from postweaning pigs with diarrhoea or oedema disease in Korea

A PCR was used to determine the genotypic prevalence of five fimbrial adhesins (F4, F5, F6, F41 and F18), two heat-stable enterotoxins (STa and STb), the heat-labile enterotoxin (LT), and the shiga toxin 2e (Stx2e) in 230 isolates of Escherichia coli from postweaning pigs with diarrhoea or oedema disease. Ninety-four (40.9 per cent) of the isolates carried genes for at least one of the fimbrial adhesins or toxins. Genes for the F18 fimbrial adhesin were detected in 18.3 per cent, and genes for F4, F6, F5 and F41 were detected in 10.0 per cent, 4.3 per cent, 1.7 per cent and 0.8 per cent of the isolates, respectively. Genes for STa, STb and LT were detected in 25.7 per cent, 15.2 per cent and 8.7 per cent of the isolates, respectively. Genes for Stx2e were detected in 36 (15.6 per cent) of the isolates, and among them 24 also contained the gene for F18ab and four also contained the gene for F18ac.