Partial lobectomy of bovine liver: a new biopsy technique.

A surgical technique has been developed for partial lobectomy of the bovine liver to obtain greater than 25 gram liver samples. Vertical mattress sutures, backed with plastic tubing, were replaced in the liver near the incision line to provide hemostasis. Hemostasis of the cut surface of the liver was adequate in each case. Postoperative recovery was uneventful and only minor adhesions were found later by laparotomy and at necropsy.     

Partial purification and characterization of proteins with growth promoting activities from ovine mammary gland secretions.

Developmental regulation of growth promoting activities in mammary secretions of pregnant Awassi ewes was defined, and growth factors contained in these secretions were partially purified and characterised. Mammary secretions from pregnant ewes enhanced fibroblast cell (AKR-2B) and mammary cell (CID-9 cell strain) proliferation to levels comparable to that induced by 10% Foetal calf serum. Major milk proteins in mammary secretions collected from pregnant ewes one month prior to lambing up to one week after lambing, were resolved by SDS-PAGE, while gelatinases were resolved by zymography. Gelatinase activity was noted prior to P134 and decreased thereafter to reach a minimum during lactation. This decrease was concomitant with the onset of casein production. It is during this critical developmental period that highest growth promoting activity in mammary secretions was detected.Secretions with highest growth promoting activity were fractionated by ion exchange and gel filtration chromatography. Two heat-resistant, trypsin/chymotrypsin sensitive, growth-promoting activities were characterised. The first, designated ovine mammary derived growth factor-1 (oMDGF-1), had around a 30 kDa molecular weight and eluted at 0.65 M NaCl gradient on cation ion exchange chromatography. The second, oMDGF-2, eluted under gel filtration conditions at a molecular weight of 50 kDa and 150 kDa. oMDGF-1 induced changes in Connexin 43, but not in beta-casein mRNA expression by CID-9 mammary cells.In conclusion, growth factor activities in ewe mammary secretions peak during gestation at a period that overlaps maximal gelatinase expression and precedes milk protein synthesis. The factors modulate mammary cell function and may play a role in mammary gland development.     

Partial purification of a serum fraction from fasted pigs that inhibits proliferation of cultured myogenic cells

Sera from pigs fasted as little as 24 h appears to contain a factor(s) that inhibits proliferation of myogenic cells in culture. An inhibitor of myogenic cell proliferation has been partially purified from this sera by using a combination of gel filtration and immunoaffinity chromatography. The inhibitory activity elutes from a Sephacryl S-300 column at a Kav (elution minus void volume divided by total minus void column volume) between .41 and .59. Proteins banding at 76 and 67 kilodaltons appear to predominate on sodium dodecyl sulfate polyacrylamide gels of this fraction. Small quantities of each of these proteins were electrophoretically purified and used to elicit production of anti-76 and anti-67 immunoglobulin G in rabbits. These antibodies were used to prepare anti-76 and anti-67 column was particularly useful in isolating the inhibitor because it removed mitogens that made detection of the inhibitory activity difficult. The partially purified inhibitor inhibits proliferation of L6 myogenic cells in a concentration-dependent manner. On sodium dodecyl sulfate polyacrylamide gels, the predominant proteins in the inhibitor fraction band at approximately 63 and 61 kilodaltons. Inhibitors of myogenic cell proliferation may play an important role in balancing the effects of positive growth factors.     

Partial purification and characterization of a protein in porcine follicular fluid which restricts sperm-egg interaction in vitro.

An attempt was made to isolate and characterize a component in preovulatory porcine follicular fluid (pFF) which has a restricting effect on sperm-egg interaction in vitro. Using the zona-free hamster ova (eggs) penetration assay as an in vitro test system, it was shown previously that the numbers of porcine spermatozoa attached to or penetrated into each egg and the number of eggs with sperm attached or penetrated decreased significantly as the concentration of pFF was increased in the culture medium. In the present study, the component in pFF having these effects was shown to be a heat stable, nonsteroidal substance which retained its activity after dialysis, lyophilization and gel filtration chromatography. The activity was also found to be present in preovulatory homologous serum. Separation of the material on protein type gel filtration columns with detection at 280 nm, together with the banding seen with Coomassie staining on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), suggests that it is a protein. Based on high pressure liquid chromatographic separation (HPLC) and SDS-PAGE analyses, the bioactivity could be due to a single protein of 87 kD or to one or more of three smaller proteins, possibly disaggregated products of the 87 kD protein, in the range of 26-28 kD.     

Muscle degeneration and liver necrosis in the pig: Report of a natural outbreak

Extract

Over the last 3 years four dogs with lesions on the neck have been referred by veterinarians to the Department of Veterinary Pathology and Public Health, Massey University and the Palmerston North Animal Health Laboratory.     

Establishment of Ascaris suum in the pig: development of immunity following a single primary infection

Development of immunity after a single primary infection of Ascaris suum in pigs was investigated with regard to the worm population dynamics of a superimposed A. suum infection, host immune response and gross liver pathological changes. Group A was given a primary infection of 60,000 infective A. suum eggs and group B was left uninfected. Four weeks later both groups A and B were inoculated with 1,000 A. suum eggs, and subgroups were slaughtered 7, 14 and 21 days post challenge infection (p.c.i.). An uninfected control group C was slaughtered on day 21 p.c.i. The challenge worm recovery in group A was reduced compared to group B by 12%, 50% and 75% on day 7, 14 and 21 days p.c.i., respectively. In both groups was the expulsion of worms initiated between day 14 and 21 p.c.i. However, in group A the worms were recovered more posteriorly in the small intestine and 21 days p.c.i. the mean worm length was significantly shorter than in group B (p = 0.01). The results above were associated with significantly higher (p < 0.05) antibody response and higher eosinophil counts in group A compared to group B. The present results suggest that the larval growth and survival of a challenge infection are decreased, probably due to higher antibody and eosinophil attack during the migratory phase.     

Viral susceptibility of a cell line derived from the pig oviduct.

Seventeen of 24 RNA viruses and eight of nine DNA viruses replicated in a cell line derived from a pig fallopian tube. The following RNA viruses grew poorly in it: the virus of transmissible gastroenteritis of pig and the swine-influenza, Sendai and bovine para-influenza type 3 viruses. Among other RNA viruses an untyped swine para-myxovirus and some picornaviruses, rhabdoviruses and togaviruses attained high titers and produced an extensive cytopathic effect. Among the DNA viruses a porcine adeno, equine rhinopneumonitis, infectious bovine rhinotraceheitis, pseudorabies and porcine cytomegalo viruses replicated in pig fallopian tube cells as well as in other cells generally used to grow them.     

Immunochemical analyses of serum antibodies from pig herds in a Salmonella non-endemic region.

In a large comparative survey of Danish and Swedish slaughter pig herds performed prior to this work, it was unexpectedly found that some Swedish herds harbored seropositive pigs. Serum samples from the Swedish herds had moderate responses in the Salmonella mix-ELISA (detecting serogroup B and C1 infections) compared to the Danish herds classifying some of them as seropositive using a cut-off value at 40 OD%. In Sweden, extensive Salmonella control is carried out by bacteriological screening of feces and lymph nodes, and the overall prevalence has been proven to be below 0.1%. The serological positive results were therefore unexpected; hence the reactivities of the Swedish sera were studied by a number of immunochemical analyses (Western blot, indirect ELISA, inhibition ELISA, avidity ELISA) and compared to sera from Danish pig herds with verified Salmonella infections ("the reference sera").In Western blot, the Swedish sera had high binding reactivities against Salmonella Typhimurium LPS of different molecular weights, and gave binding patterns similar to that of the reference sera. Pre-incubation with free S. Typhimurium LPS or PS (the polysaccharide part of LPS) was able to inhibit the reactivity of the Swedish sera in the mix-ELISA. Reactivities against other related bacterial LPS such as Citrobacter freundii LPS and Yersinia enterocolitica O:3 LPS were observed in the Swedish sera, but these LPS antigens were unable to inhibit the reactivities in the mix-ELISA as efficiently as S. Typhimurium LPS. Furthermore, the Swedish sera did not bind Salmonella LPS of another serogroup (S. Meleagridis LPS, serogroup E1) or rough Salmonella LPS, both lacking the specific O-antigenic parts of S. Typhimurium LPS. The avidity of the Swedish sera was much lower than the avidity of the reference sera, which could indicate the presence of transient low-dose infections or stimulation by inactivated bacteria in feed. The results obtained in this investigation strongly indicate that the Swedish sera contain antibodies directed against the O-antigenic part of LPS from S. Typhimurium or possibly on as yet unknown bacterium.     

Evidence of a mixed population from uterine tube epithelium in a continuous line of pig cells.

The pig uterine tube (PFT) cell line is composed of a mixed population which is undifferentiated. However, specific markers indicating the original tissue of the uterine tube were shown if cells differentiated into epithelial cells forming spheroids in the 254th subculture. Ciliated and secretory cells, and cells with a basal lamina and interstitial collagen were observed in the spheroids. Microlumina found in the spheroids appeared morphologically similar to the lumen of the uterine tube. These observations indicate that undifferentiated cells can multiply in vitro and keep their potentiality of differentiation for future expression. It is proposed that the PFT cell line was partly derived from epithelial cells originally harvested from the PFT.     

The isolation and identification of Leptospira interrogans serovar bratislava from a pig in Germany.

During a study on the improvement of selective media for the isolation of leptospires from clinical material, leptospires were isolated from the kidneys of a pig. Test material was cultured in EMJH-medium containing 0.4% rabbit serum and 3 inhibitory substances (Rifampicin 10 micrograms/ml, Amphotericin B 2 micrograms/ml, 5-Fluorouracil 100 micrograms/ml). The cultured leptospira-strain (Berlin 406) was identified to serogroup level using the cross agglutination method and it was further typed to serovar level by MAB's, factor analysis and restriction endonuclease analysis (REA). MAB typing of Berlin 406 gave an agglutination pattern profile typical of serovar bratislava. Factor serum identification clearly identified this strain as serovar bratislava. On REA examination, Berlin 406 gave a profile identical to that of the serovar bratislava type strain Jez Bratislava i.e. genotype B1. This is the first report of a confirmed isolate of Leptospira interrogans serovar bratislava from domestic animals in Germany. There exist a number of possibly important implications as this agent is being incriminated in the cause of clinical disease not only in pigs, but also in horses and dogs in other countries.     

Heterogeneity of human lymphocyte Fc receptors: Studies using heat-aggregated and antigen-complexed IgG from human, rabbit, guinea pig, horse and goat

We have studied the ability of human peripheral blood lymphocytes (HuPBL)⁴ to interact with IgG from several animal species. Three functions or activities that are reported to depend on an interaction between complexed IgG and HuPBL receptors (R) for the Fc piece of IgG (FcγR) were compared: (1) antibody-dependent cell-mediated cytotoxicity (ADCC); (2) binding of heat-aggregated IgG (aggG); and (3) rosette formation with IgG-sensitized erythrocytes [RBC-A(γ)]. IgG (and IgM) antibodies to chicken erythrocytes (CRBC) were purified from the sera of the following species after injection with CRBC stroma: (1) horse (Ho); (2) goat (Go); (3) rabbit (Ra); and (4) guinea pig (Gp). Good IgG-agglutinating antibody titers were obtained from each injected species.

Using ⁵¹Cr-labeled CRBC targets and HuPBL effector cells, only Ra anti-CRBC IgG gave good ADCC at high dilutions. Ho and Go anti-CRBC (IgG) failed to give A C , and p anti-CRBC (IgG) gave approx. 30% of the level of kill as Ra. Ra Fab'₂ fragments of IgG antibody failed to produce ADCC.

Treatment of HuPBL with Ra anti-lymphocyte serum (ALS) almost totally ablated ADCC, whereas HoALS failed to alter ADCC. Pretreatment of HuPBL with aggG showed that Ra or Hu aggG gave essentially equal inhibition of ADCC, Gp gave approx. 30% of the degree of inhibition as Hu and Ra, and Ho or Go aggG had essentially no effect of ADCC. These results confirmed the following order of ability of IgG to interact with HuPBL ADCC killer (K) cells: (Hu )Ra > Gp Ho, Go. The data suggest that Gp IgG interacts with only a subpopulation (≈ 30%) of HuPBL K cells.

The binding of aggG to total HuPBL failed to strictly correlate with the ADCC results or with the results of rosette formation between total HuPBL and CRBC-A(γ). The observations suggest that there is a heterogeneity of FcγR between K and non-K cell subpopulations of HuPBL both in terms of the type of complexed IgG they are able to bind, and in terms of the species of origin of the IgG. The data also support contentions that FcγR that bind RBCA(γ) complexes differ from those that bind aggG.     

某猪场仔猪大肠杆菌的分离鉴定与药敏试验

采集大竹县某养猪合作社疑似发生黄、白痢的仔猪直肠拭子病料,通过病原分离、培养及生化鉴定,得出分离菌为致病性大肠杆菌,是引起该场仔猪腹泻的主要病原。采用E.coli标准抗O型血清凝集试验进行血清型鉴定,得出分离菌株的优势血清型分别为O20、O101、O141;通过对30种抗生素类药物进行敏感性试验,得出分离的E.coli对复达欣(头孢他啶)、多粘霉素B高度敏感,对其余药物中度敏感或耐药。