Milk flow and udder health in cows after treatment of covered teat injuries via theloresectoscopy: 52 cases (2000-2002)

OBJECTIVE: To determine milk flow, somatic cell counts (SCCs), and the incidence of clinical mastitis in cows that had undergone theloresectoscopy for treatment of teat stenosis caused by mucosal detachment in the region of the streak canal or Fürstenberg's rosette. DESIGN: Retrospective study. ANIMALS: 52 cows with teat stenosis that were treated via theloresectoscopy. PROCEDURE: Medical records of eligible cows were reviewed. Additional data regarding milking ease, SCC, development of clinical mastitis of the affected gland, and whether the cow remained in the herd were collected via owner-completed questionnaires. RESULTS: 49 of 52 questionnaires were completed. At referral, teat sinusitis was diagnosed in 29 of 52 cows. Milk flow was normal in 38 of 41 treated teats at discharge and in 24 of 40 during the next lactation. Thirteen of 49 cows were culled during the next lactation because of abnormal udder health. High SCC and teat sinusitis at referral and development of clinical mastitis during the 10-day period after surgery resulted in high SCCs in the remainder of the current lactation. The incidence of clinical mastitis during the remainder of the current and during the next lactation was higher in cows that had teat sinusitis at the time of surgery, compared with those that did not. CONCLUSIONS AND CLINICAL RELEVANCE: Teat stenoses resulting from mucosal lesions in the region of the streak canal or Fürstenberg's rosette may be successfully treated via theloresectoscopy. Inflammation of the teat sinus and gland at the time of surgery may adversely affect udder health.     

Immunoglobulin E-bearing cells and mast cells in skin biopsies of horses with urticaria

The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the staining methods. No chymase-positive cells were found. In all groups of horses, cells staining with toluidine blue and for tryptase and IgE were found in the epidermis and hair follicle papilla and significantly more positively staining cells were observed in the subepidermal dermis compared with the deep dermis. Horses with urticaria had significantly more IgE-bearing cells in the subepidermal dermis than control horses. However, horses with urticaria had significantly fewer toluidine-blue-stained mast cells in both subepidermal and deep dermis compared with the insect bite hypersensitivity and pemphigus foliaceus groups. This study suggests that IgE-mediated reactions play a role in the pathogenesis of urticaria.     

Dermatophilus congolensis bovine dermatophilosis in the French West Indies. III. A comparison between infected and non-infected cattle

The determination of the distinctive features between infected and uninfected cattle by Dermatophilus has been performed among 93 bovine stock in La Martinique, and 120 in La Guadeloupe and Saint-Martin Islands. Nearly half of the herds had been or were infected. Morbidity rates reach 33 per cent in La Martinique and 29 per cent in La Guadeloupe with a mortality ratio of 15 per cent and 5 per cent respectively. No frequency difference could be observed with respect to the season or the geographical area. Similarly, differences are little or nil as regards animal exposure toward aggressive factors such as sun, soil moisture, thorns, etc. On the other hand, the presence of Amblyomma variegatum is a determining factor considering the prevailing situation in La Martinique, where all breeds of cattle are sensitive to the disease. In this case, 63 per cent of the tick infested cattle develops dermatophilosis versus 2.5 per cent for the still uninfected animals. Conversely, in La Guadeloupe were Creole zebus are highly resistant (as a consequence of their natural selection), only 27 per cent of the infected stock suffers from this illness. In these two islands, regular dipping measures have proved to be beneficial in that it reduces the disease frequency. The study also reveals an underlying typology of the various rearing systems, thus allowing their classification as for their behaviour and response when meeting illness. In La Martinique, whatever they may be, quite none of them is infected in the tick free area. In the tick infested zones, the traditional small breeders rearing a sensitive cattle and who do not care with prophylactic rules, are mostly stricken, while more structured ones have succeeded in controlling the disease, owning to some appropriate measures together with a fair animal management. On the other hand, in La Guadeloupe where this tick is cosmopolitan, the small breeders who run a resistant Creole cattle, are not concerned, despite a rudimentary prophylactic behaviour. Conversely, the intensive rearing system, based upon improved imported breeds, meets great difficulties to master the infection.     

Crystal structure of a divalent metal ion transporter CorA at 2.9 angstrom resolution

CorA family members are ubiquitously distributed transporters of divalent metal cations and are considered to be the primary Mg2+ transporter of Bacteria and Archaea. We have determined a 2.9 angstrom resolution structure of CorA from Thermotoga maritima that reveals a pentameric cone-shaped protein. Two potential regulatory metal binding sites are found in the N-terminal domain that bind both Mg2+ and Co2+. The structure of CorA supports an efflux system involving dehydration and rehydration of divalent metal ions potentially mediated by a ring of conserved aspartate residues at the cytoplasmic entrance and a carbonyl funnel at the periplasmic side of the pore.     

Is the decline of birds and amphibians in a steppe lake of northern Patagonia a consequence of limnological changes following fish introduction?

• 1. Laguna Blanca, in Laguna Blanca National Park, is a lake in Patagonia which has been designated as a Ramsar site since 1971 because of bird diversity and abundance and importance for nesting, particularly for the black neck swan, Cygnus melanocoryphus. It is also valued for its populations of endemic amphibians, Atelognathus patagonicus and Atelognathus praebasalticus.
• 2. Avian and amphibian populations have decreased dramatically in recent years. Percichthys colhuapiensis, Percichthys trucha (Pisces, Percichthyidae), Salmo trutta and Oncorhynchus mykiss (Pisces, Salmonidae) were introduced into Laguna Blanca in 1965. Since 1986, no Atelognathus frogs have been found. The abundance of swans and coots, which are strongly associated with macrophytes for nesting and feeding, has diminished drastically, whereas piscivorous birds have increased.
• 3. The fishless condition of some neighbouring small lakes with abundant pond weeds, aquatic birds and endemic amphibians, was assessed in order to compare the physical and chemical characteristics and the quantitative composition of the benthos among lakes. Fish presence at Laguna Blanca and its absence at El Burro, Antiñir and Jabón lakes, were confirmed. Compared with previous results, it seems that the abundance of Amphipoda (Hyalella), Copepoda and Cladocera at Laguna Blanca has decreased, while Acari has increased and Notostraca has disappeared. Water transparency has diminished in Laguna Blanca and now is lower than that of fishless lakes.
• 4. P. colhuapiensis were captured only in Laguna Blanca, with the highest captures in the littoral zone. The population shows rapid individual growth in the early years and an absence of fish older than 6 years. The preponderance of benthos and the presence of macrophytes in the gut contents of adult P. colhuapiensis appear to indicate that they are important consumers of these resources.
• 5. This paper concludes that fish introduction in Laguna Blanca led to a complex trophic cascade effect (fish predation on tadpoles, fish competition for avian food, bottom disturbance, zooplankton reduction) producing deleterious effects on the amphibian and bird populations.

Copyright © 2006 John Wiley & Sons, Ltd.     

The fern sporangium: a unique catapult

Various plants and fungi have evolved ingenious devices to disperse their spores. One such mechanism is the cavitation-triggered catapult of fern sporangia. The spherical sporangia enclosing the spores are equipped with a row of 12 to 13 specialized cells, the annulus. When dehydrating, these cells induce a dramatic change of curvature in the sporangium, which is released abruptly after the cavitation of the annulus cells. The entire ejection process is reminiscent of human-made catapults with one notable exception: The sporangia lack the crossbar that arrests the catapult arm in its returning motion. We show that much of the sophistication and efficiency of the ejection mechanism lies in the two very different time scales associated with the annulus closure.