Possible role for calmodulin in calcium paradox-induced heart failure

Several phenothiazines were found to provide significant protection against loss of tissue creatine phosphokinase caused by the calcium paradox. The concentration of phenothiazine required for protection lies within the range generally attributable to their calmodulin inhibition properties. Moreover, the order of effectiveness in protecting the calcium overloaded myocardium is consistent with their potency as calmodulin inhibitors (trifluoperazine greater than chloropromazine greater than promethazine). The most potent calmodulin inhibitor was shown to dramatically reduce the amount of creatine phosphokinase loss from calcium depleted hearts exposed to buffer containing calcium under anoxic conditions. On the other hand, the drug failed to alter the oxygen-dependent component of the calcium paradox. It also failed to prevent the proteolytic conversion of xanthine dehydrogenase to xanthine oxidase. The possibility that calmodulin activation promotes cellular damage by activating either directly or indirectly specific membrane cellular phospholipases is discussed. Also discussed is the hypothesis that oxygen-dependent damage may be linked to the generation of superoxide anion by the enzyme xanthine oxidase.

Virus-like particles, 45 to 65 nm, in intestinal contents of neonatal calves

Enveloped virus particles 45 to 65 nm in diameter, tentatively called minicorona virus, were detected by electron microscopy in the intestinal contents of one normal and seven diarrheic calves in Quebec dairy herds. The agent was shown to be antigenically unrelated to the Nebraska calf diarrhea coronavirus and to the bovine viral diarrhea virus by counterimmunoelectrophoresis and fluorescent-antibody techniques. Antibodies against these particles were demonstrated in the serum of affected calves using immunoelectron microscopy. The agent could not be isolated in cell cultures and its possible role as etiological agent in calf diarrhea is still to be determined.

The pathophysiology of superoxide: roles in inflammation and ischemia

The superoxide radical plays major roles in the neutrophil-medicated acute inflammatory response and in postischemic tissue injury, although the sources and actions of the radical are quite different in these two pathological states. While neutrophils produce superoxide for the primary purpose of aiding in the killing of ingested microbes, a second useful function has evolved. The superoxide released from actively phagocytosing neutrophils serves to attract more neutrophils by reacting with, and activating, a latent chemotactic factor present in plasma. Superoxide dismutase, by preventing the activation of this superoxide-dependent chemotactic factor, exerts potent anti-inflammatory action. During ischemia, energy-starved tissues catabolize ATP to hypoxanthine. Calcium transients in these cells appear to activate a calmodulin regulated protease which attacks the enzyme xanthine dehydrogenase, converting it to a xanthine oxidase capable of superoxide generation. When the tissue is reperfused and reoxygenated, all the necessary components are present (xanthine oxidase, hypoxanthine, and oxygen) to produce a burst of superoxide which results in extensive tissue damage. Ischemic tissues are protected by superoxide dismutase or allupurinol, an inhibitor of xanthine oxidase.

Coronavirus-like Particles in the Feces of a Cat with Diarrhea

Coronavirus-like particles were visualized in the feces of a young domestic shorthair female cat with diarrhea. On the surface projections, these particles could be distinguished from the enteric coronavirus-like particles of human, dog, cattle and monkey origin. They appeared morphologically similar to a feline enteric coronavirus recently described by other authors. A precipitin antigen was detected in the cat feces by counterimmunoelectroosmophoresis using a rabbit antibovine coronavirus serum.

Antigenic variations among calf diarrhea coronaviruses by immunodiffusion and counterimmunoelectrophoresis

The antigenic relationship among five bovine coronavirus isolates was studied using the counterimmunoelectrophoresis (CIE) and immunodiffusion (ID) techniques. By CIE, two precipitating antigens were observed for each coronavirus isolate. One antigen identified as the "M" coronaviral antigen was found to be common to the five isolates while the second antigen identified as the "m" coronaviral antigen differed between the isolates. Considering the later antigen, the isolates studied were placed in two antigenic groups, members of the same group being indistinguishable for the two antigens. By ID, reactions of partial identity were noted between viruses of the different groups.

A simple technique for preparation of chicken-embryo-skin cell cultures

A simple, rapid technique was developed for preparing chicken-embryo-skin cell cultures utilizing trypsinization of the skin of intact 12-day-old chicken embryos. When cell cultures were inoculated with fowl pox virus, those that consisted of at least 80% epithelial cells yielded a higher virus titer than fibroblast cell cultures.

Interferon, fluorescent antibody, and neutralizing antibody responses in sera of calves inoculated with bovine respiratory syncytial virus

Interferon, fluorescent antibody, and neutralizing antibody responses were studied in sera of 9 calves inoculated with bovine respiratory syncytial virus, in relation to viral shedding and clinical signs of disease. The calves (5.5 to 6.5 weeks of age) were assigned to 3 groups. Group I was inoculated once with the virus, and groups II and III were challenge exposed at postinoculation day (PID) 15 or 37. Serum-neutralizing and indirect fluorescent antibody techniques were used to measure antibody responses. The plaque-inhibition technique, using vesicular stomatitis virus, was applied to measure serum interferon titers. The virus was recovered by inoculation of nasal secretions onto cell cultures. Fluorescent antibody was detected in all calves on PID 3, with maximum titers appearing approximately on PID 10. Low neutralizing antibody was detected in most animals on PID 3, and titers peaked approximately 4.5 weeks after inoculation and then decreased. Interferon titers were high in all calves during the early stage of infection, dropped to undetectable amounts by PID 6, and reappeared in low amounts at least 1 week later. All infected calves manifested clinical signs of disease by PID 4 to 9. Clinical signs of disease were not observed after challenge exposure at PID 15 or 37, and anamnestic responses were not detected. Virus was recovered after challenge exposure at PID 15, but not at PID 37.

[Calf coronavirus neonatal diarrhea. A literature review (author's transl)]

Calf coronavirus neonatal diarrhea. A literature reviewThe importance of the calf coronavirus in the etiology of neonatal diarrhea of calves has been reported many times from various countries. A literature review concerning this virus is presented in this paper. A detailed description of the pathogenesis, clinical signs and lesions of the disease, as well as the morphological, physicochemical, biological and antigenic characteristics of the virus are presented. The immunity of the calf against this virus and the principal diagnosis technics are also discussed.

Bovine herpesvirus type 1 in the sperm of a bull from a herd with fertility problems

A herd of 125 Holstein cows manifested fertility problems for two years. The number of services per pregnancy was 2.97, conception rate was 33% after the first service, and the average number of open days was 127. Abortions occurred in four cows over the last 12 months. The herd was not vaccinated against any disease. Natural service by a bull and artificial insemination were used for breeding the cows. Bovine herpesvirus type 1 was demonstrated in sperm heads from the bull by direct and indirect fluorescent antibody techniques, and the virus was isolated on cell cultures. The virus was also isolated from the uterine secretions of some cows and from two aborted fetuses.

Experimental infection of calves with bovine respiratory syncytial virus (Quebec strain)

An experiment was designed to evaluate the clinical, haematological, viral and serological aspects of bovine respiratory syncytial virus infection in calves. Eleven calves were inoculated intranasally with bovine respiratory syncytial virus (Quebec strain) in aerosol. Clinical, haemotological and serological responses of the calves and virus shedding were monitored. The experimentally infected animals manifested moderate to severe signs of respiratory disease. The parameters used to evaluate the severity of the disease included ocular discharge, conjunctivitis, lung sounds, nasal discharge, pyrexia and leukopenia. The animals were scored accordingly (scale infected 70.8-148.5, control 22-29.3). Highest disease scores were observed between day 6-9 after infection. Virological and serological assessment demonstrated that the observed clinical picture was due to bovine respiratory syncytial virus infection.

Bovine respiratory syncytial virus in Quebec: antibody prevalence and disease outbreak

The prevalence of antibody to bovine respiratory syncytial virus in Quebec and the role of the virus in a respiratory disease outbreak was investigated. The indirect immunofluorescent, neutralization and haemagglutination inhibition techniques were used to carry out this study. Of the 1,444 adult animals examined 519 (35.9%) had antibody to bovine respiratory syncytial virus. These positive reactors were found in each agricultural region of Quebec. The highest (53.0%) and the lowest (21.8%) prevalence was observed in the sera collected by the laboratories of St. Hyacinthe and Sherbrooke. During a respiratory disease outbreak affecting 77 calves on a farm, bovine respiratory syncytial virus was shown to be associated with infectious bovine rhinotracheitis, bovine parainfluenza type 3, bovine viral diarrhea viruses and bovine adenovirus type 3 as detected by seroconversion. Of the 38 seroconverted animals 14 were seropositive to bovine respiratory syncytial virus.

[Influenza viruses in man and animals. A literature review (author's transl)]

Influenza viruses in man and animals. A literature reviewA literature review on the influenza viruses is presented in this paper. A description of the disease in man and domestic animals, as well as general considerations on morphological, physicochemical and antigenic properties of these viruses is given. Emphasis is put on the role of the antigenic changes of these viruses with regard to the epidemiology of the disease, as well as on the possible origin of the pandemic and epidemic strains.

Counterimmunoelectroosmophoresis for detection of neonatal calf diarrhea coronavirus: methodology and comparison with electron microscopy

A counterimmunoelectroosmophoresis (CIE) technique is described for the detection of calf diarrhea coronavirus antigens in intestinal contents. The antibody reagent was prepared in rabbits against the Nebraska calf diarrhea coronavirus adapted to Vero cells and purified by density gradient centrifugation. The method was applied to intestinal contents of diarrheic and normal calves and compared with electron microscopy (EM). Calf coronavirus antigens were detected in intestinal contents of 44% (21/48) of the diarrheic calves and 24% (4/17) of the normal calves. Two precipitin lines could be observed in the majority of the positive samples. When compared with EM, CIE detected more positive animals. In only two cases (2/20) CIE was negative despite the visualization of coronavirus particles by EM.

Morphological and quantitative study of spirochetes in the feces of normal and infected SPF pigs during the incubation period of swine dysentery

Spirochetes found in feces of normal and infected pigs during the eight days preceding the onset of the clinical signs of swine dysentery have been studied using electron and phase contrast microscopy. According to their dimensions, diameter, length and pitch, three morphological groups have been described: small, intermediate and large spirochetes. On the basis of their axial filaments arrangement, eight types have been observed. Compared to the control pigs, there was no increase in the total number of spirochetes in infected pigs, except at day 6 before the onset of clinical signs. However, infected pigs have shown a wide spectrum of different morphological types of spirochetes in comparison to control, uninfected pigs, which showed only the type "1-2-1" spirochete of axial filaments arrangement. This last type was predominant in infected swine during the entire incubation period as compared to other spirochete types described.

Effects of endotoxin on carbohydrate metabolism in inbred mice

Effects of endotoxin on carbohydrate metabolism were studied in A/HeJ (endotoxin-sensitive) and C3H/HeJ (endotoxin-resistant) inbred mice. A/HeJ mice developed hypoglycemia within two hours after endotoxin injection, yet liver glycogen content did not differ from controls. Similarly treated C3H/HeJ mice did not develop significant hypoglycemia. Administration of glucagon to endotoxin-treated A/HeJ mice failed to elevate their blood glucose concentrations, while endotoxin-treated mice of the same strain did respond to dibutyryl cyclic AMP with a significant elevation of blood glucose. C3H/HeJ mice on the other hand responded to glucagon and dibutyryl cyclic AMP with elevated blood glucose. Endotoxin-treated C3H/HeJ but not A/HeJ mice were able to carry out gluconeogenesis induced by prednisolone, while both inbred strains showed active glycogenesis after administration of an exogenous glucose load. Administration of glucagon resulted in diminished liver glycogen concentrations in A/HeJ endotoxin-treated mice suggesting no impairment of glycogenolysis. The inability of endotoxin-treated A/HeJ mice to respond to glucagon could be due to impairment of gluconeogenesis. Although endotoxin interfered with the capacity of both inbred strains to respond to glucagon administration with elevation of liver cyclic AMP, the effect was significantly more severe in A/HeJ mice. The susceptibility of A/HeJ mice to the lethal effect of endotoxin may be related to the apparent sensitivity of carbohydrate metabolic pathways to disturbance by endotoxin.

[An experimental study on the variation of serum antibody levels relative to the life cycle of the horsefly]

The changes of antibody titers in the sera of colts infested naturally or artificially with Gasterophilus have been determined in relation to the life cycle of this arthropod using passive hemagglutination, complement fixation, double diffusion techniques and saline extracts of antigens from the third larval stages of Gasterophilus intestinalis and G. nasalis.In the sera of the infected animals the hemagglutinating antibodies were present at low titers at the third week post-infestation by using somatic extract of G. intestinalis and at the seventh week in case of G. nasalis. At eight weeks post-infestation the antibody titers reached their maximum 1:8192 (G. intestinalis) and 1:4096 (G. nasalis), then dropped at 12 weeks post-infestation. The complement fixing antibodies were present occasionally between the seventh and 11th weeks after infestation. Precipitating antibodies were absent in all sera.

Concentration of IgG in serum and large intestine of dysenteric swine

Radial immunodiffusion tests employing swine IgG monospecific antiserum have permitted the determination of the IgG concentration in the serum and large intestine of healthy and dysenteric 12 week old boars. Specific and significant increases in IgG were observed in serum and colon during the acute from of the disease, but in the cecum only, during the subacute phase of the disease.

A preliminary study on the intestinal flora of cecum and colon of eight, ten and 12 week old swine

Using a replica-plating method and differential culture media, members of the Enterobacteriaceae and Pseudomonaceae were determined quantitatively in the colon and cecum content of pigs from different litters, born on the same farm and kept under the same environmental conditions, from the age of six weeks. The bacterial flora in pigs of eight, ten and 12 weeks of age showed little significant quantitative variation. Pigs of 12 weeks of age differed significantly from younger ones with respect to Aeromonas, Edwardsiella, staphylococci and molds. The existence of a variable flora is underlined as well as the fact that Vibrio coli represents an important member of the intestinal flora at that age. No significant variation in the pH of the chyme of the colon and cecum was recorded.

[Quantitative study of the bacterial flora of the large intestine of dysenteric swine]

The bacterial flora and the pH of the large intestine of dysenteric swine during acute subacute and chronic phases have been submitted to quantitative and qualitative studies. The methods used are based on primary isolation and differentiation of the bacteria by the use of selective media and the subsequent differentiation using the replica plating technique. The most characteristic changes are the following:1. A significant increase of the pH of the chyme in the large intestine during acute dysentery2. A significant increase of Vibrio, Escherichia coli and Staphylococcus in the colon and cecum during acute dysentery.3. A significant increase of Shigella in the colon and cecum during subacute dysentery.4. The almost total disappearance of Aeromonas and of the yeasts in the large intestine during acute, subacute and chronic dysentery.5. A significant decrease of Klebsiella, in the cecum, during acute dysentery and of the fungi during subacute dysentery.6. Decrease of Streptococcus in the colon during acute dysentery.7. The total quantitative flora of the large intestine do not change very much.

Endotoxin sensitivity of inbred mouse strains

Inbred mouse strains show characteristic susceptibility to S. typhimurium infections. The sensitivity of the same strains to endotoxin is not parallel. While C3H/He J and C57B1/6J mice were highly susceptible to infection they showed more resistance to purified endotoxin than A/J, a mouse strain relatively resistant to infection. These findings suggest that the death of mice during S. typhimurium infection is not due only to toxic effects of its lipopolysaccharide.

A simple procedure for the preliminary identification of aerobic gram negative intestinal bacteria with special reference to the Enterobacteriaceae

A useful procedure is described for rapid identification of some Gram negative bacteria during quantitative studies of the intestinal flora from various species. The methods used are based on primary isolation and differentiation of the bacteria by the use of MacConkey agar and the subsequent differentiation according to definite procedure using the replica plating technique.