Observations on the transmissibility of lentogenic strains of Newcastle disease virus: significance of variables

Virus strain and age of chicken influenced the transmissibility of lentogenic strains of Newcastle disease virus (NDV). The ability of LaSota, B1, V4, CT, F, and Ulster strains to spread from cages of oronasally inoculated chickens to adjacent cages of susceptible chickens was assessed by virus isolation, serology, and immunity to challenge with virulent NDV. Although all inoculated chickens were immune to challenge, the immunity of contact chickens ranged from 100% for LaSota and CT strains to 0% for Ulster strain. The transmissibility of B1 and V4 strains for chickens 1, 4, 8, and 16 weeks old was assessed by within-cage contact infection, exposure to contaminated food and water containers, and exposure to air from infected chickens. Serology and immunity to challenge with virulent virus were used as criteria. Differences in transmissibility were observed for the strain of virus used, route of exposure, and age of chickens. Care must be used in interpreting the significance of strain differences until the effect of variables can be minimized by further improvements in design of the test procedure.     

Changes in gene expression following traumatic brain injury in the rat

1. The relationship between immunoreactive inhibin and follicle-stimulating hormone (FSH) was studied in male and female chickens from hatch to sexual maturity. Plasma inhibin was estimated by a heterologous radioimmunoassay validated for use in the chicken. FSH was measured by a recently developed homologous radioimmunoassay. 2. In a cross-sectional study, blood samples and gonads were collected from chickens of both sexes at 1, 3, 5, 7, 14, 21 and 28 d after hatching and subsequently at 14-day intervals until 182 d of age. 3. In the female, plasma progesterone concentration (P4) progressively increased during sexual development. The plasma luteinising hormone (LH) concentration rose during the first week after hatching, and fluctuated thereafter, with troughs at 6 and 14 weeks and peaks at weeks 10 and 18. The plasma inhibin and FSH concentrations remained low until the start of puberty and increased simultaneously thereafter. However, from week 18 on, plasma inhibin continued to rise while plasma FSH fell. Hence, FSH and inhibin were positively correlated before puberty, but developed a negative correlation during sexual maturation. 4. In the male, plasma testosterone and LH concentrations increased 38- and 3.7-fold respectively over the period studied. Inhibin and FSH followed similar time courses and were consequently positively correlated. 5. These results suggest sex differences in the role of inhibin in regulating FSH secretion during development. The FSH-inhibin feedback loop may become operational at the onset of sexual maturity in the hens. In male chickens, the similar pattern of inhibin and FSH secretion suggests that inhibin secretion is driven by FSH.     

Studies on genetic and vaccination-induced resistance of chickens to lymphoid tumor transplants 2. Transmissible lymphoid tumor of Olson

Transmissible lymphoid tumor (TLT) was inoculated in wing webs of five-week-old chickens of 6 strains. About half of the chickens of each strain had been vaccinated with turkey herpesvirus (HVT) one week before challenge in the wing web with TLT. Tumors which developed at the site of inoculation usually reached maximum size within 2 weeks and then regressed. In some chickens, however, tumors developed in visceral organs and caused death in the 2nd through 5th weeks postinoculation. Comparisons among strains of chickens in Expt. 1 revealed no differences in mortality. Vaccination with HVT reduced mortality and also the incidence of wing-web tumors (WWT) in all strains of chickens. A lymphoid leukosis virus and a Marek's disease (MD) virus of low virulence were detected in preparations of TLT, and it is suggested that the immunity induced by vaccination may have been directed against tumor antigens associated with MD virus.     

Association of serum hemolytic complement levels with the major histocompatibility complex in chickens

The total hemolytic complement (C) levels in inbred line 7 chicks and adults were lower than C levels in inbred lines 2 and 3 and in outbred chickens of the same age. In all birds, adult levels of C were obtained in 5- to 6-wk-old chickens. Analysis of F1 and F3 generations clearly showed that the C level in chickens was determined by a dominant gene(s) associated with the major histocompatibility complex. Finding this association in a nonmammal strengthens the importance of the relationship between closely linked genes controlling histocompatibility, immune responsiveness, mixed leukocyte reaction, and C activity.     

Efficacy of a novel infectious bursal disease virus immune complex vaccine in broiler chickens

Two experiments were conducted to test the efficacy of a novel infectious bursal disease virus (IBDV) vaccine in broiler chickens with maternal IBDV immunity. The IBDV vaccine was formulated by mixing IBDV strain 2512 with bursal disease antibodies (BDA) to produce the IBDV-BDA complex vaccine. In Expt. I, 1-day-old Cobb x Cobb broiler chickens were vaccinated subcutaneously with either IBDV-BDA or commercial live intermediate IBDV vaccine (vaccine A) or were left unvaccinated. In Expt. 2, the vaccine A group was not included; instead, IBDV strain 2512 was included. Chickens were maintained in isolation houses. On day 28 (Expt. 1) and day 32 (Expt. 2) of age, chickens from each group were challenged with a standard USDA IBDV (STC strain) challenge. Challenged and unchallenged chickens were evaluated for their bursa/body weight ratios and antibody titers 3 days post-challenge. Bursae collected from Expt. 2 were examined histologically to evaluate bursal lesions and confirm gross examination. None of the unvaccinated chickens was protected against the challenge virus as evidenced by the presence of acute bursal lesions (edema/hemorrhage). All chickens receiving the IBDV-BDA complex or the IBDV strain 2512 (Expt. 2) were protected from the challenge virus as evidenced by no acute bursal lesions. Additionally, chickens receiving the IBDV-BDA complex vaccine or the IBDV strain 2512 had antibody titers to IBDV, indication the presence of an active immune response. In Expt. 1, chickens vaccinated with vaccine A and challenged had bursal lesions similar to those observed in the unvaccinated, challenged chickens. These chickens also showed no indication of active immunity against the virus. These results suggest that the 1-day-of-age-administered IBDV-BDA complex vaccine can induce active immunity and protection against a standard IBDV challenge in the face of variable levels of maternal IBDV immunity.     

Effect of vaccination of hens with an avirulent strain of Salmonella typhimurium on immunity of progeny challenged with wild-Type Salmonella strains

The avirulent Salmonella typhimurium chi3985 was used to vaccinate white leghorn chickens at 16 and 18 weeks of age, and the effect of maternal antibody on Salmonella colonization of progeny of vaccinated hens was assessed with S. typhimurium F98 or chi3985. Progeny of hens that had been vaccinated at 1 and 3 or 2 and 4 weeks of age with chi3985 were used to determine the effect of maternal immunity on vaccine efficacy. Vaccination of hens induced long-lasting Salmonella-specific antibodies which were transferred into eggs and were detected as immunoglobulin G (IgG) in the egg yolk. Maternal antibody was detected in the progeny of vaccinated birds as IgG and IgA in serum and intestinal fluid, respectively. The titer of maternally transmitted IgG or IgA was highest in the first week of life of the progeny and declined with age. Maternal antibodies prevented colonization of the chicks by S. typhimurium chi3985 and reduced colonization by S. typhimurium F98. Overall, chicks from vaccinated hens had significantly higher antibody responses than did the progeny of nonvaccinated hens after oral infection with Salmonella strains. Maternal antibody reduced the efficacy of vaccination of progeny with chi3985 at 1 and 3 weeks of age. But vaccination at 2 and 4 weeks of age induced excellent protection against challenge with S. typhimurium F98 or S. enteritidis 27A PT 8 in birds from vaccinated hens and in specific-pathogen-free chickens. Vaccination of chickens at 2 and 4 weeks of age has been shown to protect the birds against challenge with homologous and heterologous Salmonella serotypes. A combination of vaccination of adult animals and use of the progeny of vaccinated birds will enhance effective control of Salmonella infections in the poultry industry. This will complement the present control of Salmonella-associated food poisoning caused by Salmonella enteritidis in eggs because the avirulent S. typhimurium vaccine strain chi3985 induced excellent protection against S. enteritidis in chickens.     

Demonstration of chicken B alloantigens by the Cytotoxicity test

The activity of complements from various sources was compared in the complement-mediated cytotoxicity test, using chicken alloantisera. The highest cytotoxicity index was obtained with a pool of complements from fresh guinea pig serum and chicken serum. No difference in activity between complements from chickens of the different inbred lines was found. Using the above test, we demonstrated the B-F antigen on lymphoid cells, whereas the B-G antigen was not present.     

The susceptibility of chickens to Trypanosoma brucei subspecies

Chickens were susceptible to infection with three different stocks of the subgenus Trypanozoon: two of presumptive Trypanosoma b. brucei and one of T. b. rhodesiense. Two groups of chickens were used: the first hatched following inoculation with either T. b. brucei or T. b. rhodesiense during embryonic development, and the second were infected as adult birds. In both experimental groups, parasitaemia persisted for prolonged periods, but was mostly subpatent and detectable only by subinoculation of blood into mice. In chickens infected as embryos, parasitaemias were patent for five weeks after hatching, but subpatent thereafter (to weeks 13 to 17). Quantitative estimations of the parasitaemias of seven of the birds hatched from embryos inoculated with T. b. brucei revealed fluctuations in the number of circulating trypanosomes, with an initial peak between days 2 to 9 after hatching. Between weeks 13 to 17 after hatching the chickens appeared to have recovered spontaneously from the trypanosome infections. Homologous challenge at week 20 failed to produce a recrudescence of parasitaemia, indicative of a possible acquired immunity. The infections of ten chickens inoculated with either T. b. brucei or T. b. rhodesiense as adult birds were microscopically subpatent throughout the observation period of six weeks, but subinoculation of blood into mice showed the chickens were parasitaemic from week one and thereafter. Different aspects of infection of avian hosts by the Trypanozoon subspecies are discussed.     

B cells and T-lymphocyte subsets of the head-associated lymphoid tissues of the chicken

The head-associated lymphoid tissues of the chicken, composed of the harderian gland and the conjunctiva-associated lymphoid tissue (CALT), were studied to determine whether changes occurred in lymphocyte subpopulations as chickens age from 1 week to 8 weeks. The B cells and subpopulations of T-lymphocytes of the head-associated lymphoid tissues were identified using in situ immunohistochemical staining. Monoclonal antibodies specific for various lymphocyte surface antigens were used. The concentration of T-lymphocytes, particularly CD3+ and CD4+ cells, within the harderian gland increased with age, whereas the concentration of B cells remained the same. B-lymphocytes were observed within the germinal centers of the CALT of 4-week-old birds. The T-lymphocytes within the CALT surrounded the B-cell-rich germinal centers. CD3+ T-lymphocytes were the predominant cell population in all age groups examined. Increasing concentrations of CD3+, CD4+, and CD8+ T-lymphocytes were observed within the CALT as chicks developed from 1 week to 4 weeks of age. Finally, no changes were observed in lymphocyte populations within the CALT as chicks developed from 4 weeks to 8 weeks of age.     

Evaluation of the efficacy of Eimeria maxima oocyst immunization with different strains of day-old broiler and roaster chickens

The performances of three different strains of male and female broiler or roaster chickens immunized at 1 day of age with a drug-resistant field isolate of Eimeria maxima were evaluated in battery and floorpen immunization trials. No difference in immunization potential was seen between these strains or sexes of day-old chickens immunized with 2500 oocysts/bird of E. maxima and challenged at 10 days of age with 25,000 oocysts/bird of the same isolate in two separate battery trials. All immunized birds showed significant protection for the parameters of weight gain and midintestinal lesion scores at 7 days post challenge (PC) when compared with nonimmunized challenged controls. In two separate floorpen trials, one broiler bird strain (designated strain 2) immunized by the same procedure and challenged at 21 days of age with the equivalent of 25,000 oocysts/bird of the same isolate showed significant protection for weight gain and lesion scores at 7 days PC when compared with nonimmunized controls. Birds in these same floorpen experiments immunized with E. maxima and then fed three different anticoccidial shuttle diets (narasin and nicarbazin 90 grams/ton (g/t) in starter feed and narasin 72 g/t + roxarsone 45.4 g/t in grower feed; nicarbazin 113 g/t in starter feed and narasin 72 g/t + roxarsone 45.4 g/t in grower feed; and monensin 100 g/t in starter and grower feed) showed no interference with elicited immunity with E. maxima challenge for the same parameters measured. No significant difference was seen between any floorpen immunized bird groups for total weight gain at trial terminations (49 days of age).     

Nonbursal origin of humoral immunity: immune capacity and cytomorphological changes in chickens bursectomized as 52- to 64-hours-old embryos

Chickens sham-bursectomized as 52- to 64-hours-old embryos (SBx), chickens bursectomized at hatching (NeoBx) and chickens from which the bursal primordium was removed at 52-64 h of embryonation (EBx) were immunized with guinea pig red blood cells when 21 days old. Following the second injection of antigen, EBx chickens were found to elaborate ME-sensitive and ME-resistant hemagglutinins, to produce direct and indirect plaque-forming cells, and to contain lymphocytes bearing a specific bursa (Bu) antigen. These immune properties were more often expressed in sham-bursectomized and neonatally bursectomized chickens. Cytomorphological changes in the spleen, bone marrow and cecal tonsil of EBx chickens were typical for birds lacking the bursa. The number of lymphocytes and plasma cells in the bone marrow and liver of SBx, NeoBx and EBx chickens was very low. These results suggest that a very early embryonic bursectomy of chickens does not abolish humoral immunity completely and does not prevent the differentiation of Bu antigen-bearing lymphocytes.     

Factors affecting the bacteriological contamination of commercial washing machines

Mycoplasma gallisepticum- and Mycoplasma synoviae-free chickens were infected with 0.2 ml broth culture of M. gallisepticum strain 1226 intra air sac at 3, 14, 18, 28, 42, 49 and 65 days of age. Blood samples were taken 0-5 weeks before infection and 1-6 weeks after infection (depending on age of infection). The antibody response was examined by Western blot. As a control of infection, serum plate agglutination test (SPA), pathological lesions, and presence of Mycoplasma in air sacs were used. Antibodies to p64-67 kDa appeared in all groups of birds on the first week post-infection. Antibodies to p56 were detected from the second week post-challenge if infection was performed at 3 or 14 days of age, while on first week if challenge was done at 18, 28, 42, 49 or 65 days of age. Antibodies to p200, p120, p98, p80, p75, p72, p60, p50, p45, p40, p35, p33, p31, p28, p26, p24 and p22 were also detected.     

Developmental study of alpha-methyl-D-glucoside and L-proline uptake in the small intestine of the White Leghorn chicken

Development changes in alpha-methyl-D-glucoside and L-proline accumulation were studied using everted sleeves from the duodenum, jejunum, and ileum of chickens. Six age groups of chickens were used: 1 d and 1, 2, 3, 5 to 6, and 12 to 14 wk. Our results showed the presence of a Na+-dependent mechanism of sugar and amino acid uptake that is already fully developed at hatch. The intestinal transport activity undergoes substantial changes with age and region studied. Intracellular accumulation of alpha-methyl-D-glucoside and L-proline was greater in newly hatched chicks and then declined with age in the three regions of the small intestine, except for L-proline transport in ileum, which remained constant during the period studied. The transport mechanisms for each nutrient followed separate developmental patterns along the small intestine during the period studied.     

Synthesis and antiparasitic activities of amidinic azolated derivatives

The natural immunity status in different age groups was investigated. The positive rate of HI antibody under the age of 4 was less than 25%. The natural immunity level increased gradually with age and the positive rate of the antibody reached 80% among the group aged 13-25. Rate of seroconversion was 100% in any age group one month after immunization, and GMT rose from 13.33 to 243.16. It was suggested that immunogenicity of domestic attenuated live rubella vaccine BRD II was satisfactory. For the population with positive-antibody before immunization, the total GMT rose from 189.59 to 259.00 after vaccination and the difference between immunization before and after was highly significant. According to the above result, we suggested that the vaccination strategy for rubella among young children and women of child-bearing age should be implemented.     

The ABC Schizophrenia Study: a preliminary overview of the results

The ABC Schizophrenia Study, a large-scale epidemiological and neurobiological research project commenced in 1987, initially pursued two aims: (1) to elucidate the possible causes of the sex difference in age at first admission for schizophrenia and (2) to analyse the early course of the disorder from onset until first contact and its implications for further course and outcome. First, transnational case-register data (for Denmark and Germany) were compared, second, a population-based sample of first-episode cases of schizophrenia (n = 232) were selected and third, the results obtained were compared with data from the WHO Determinants of Outcome Study by using a systematic methodology. A consistent result was a 3-4 years higher age of onset for women by any definition of onset, which was not explainable by social variables, such as differences in the male-female societal roles. A sensitivity-reducing effect of oestrogen on central D2 receptors was identified as the underlying neurobiological mechanism in animal experiments. Applicability to humans with schizophrenia was established in a controlled clinical study. A comparison of familial and sporadic cases showed that in cases with a high genetic load, the sex difference in age of onset disappeared due to a clearly reduced age of onset in women, whereas in sporadic cases it increased. To analyse early course retrospectively, a semistructured interview, IRAOS, was developed. The early stages of the disorder were reconstructed in comparison with age- and sex-matched controls from the same population of origin. The initial signs consisted mainly of negative and affective symptoms, which accumulated exponentially until the first episode, as did the later emerging positive symptoms. Social disability appeared 2-4 years before first admission on average. In early-onset cases, social course and outcome, studied prospectively over 5 years, was determined by the level of social development at onset through social stagnation. In late-onset cases, decline from initially high social statuses occurred. Socially negative illness behaviour contributed to the poor social outcome of young men. Symptomatology and other proxy variables of the disorder showed stable courses and no sex differences. Further aspects tested were the sequence of onset and the influence of substance abuse on the course of schizophrenia, primary and secondary negative symptoms, structural models and symptom clusters from onset until 5 years after first admission.     

Fetal steroid levels at delivery

The purpose of this study was to investigate cortisol levels in the circulation of neonates following spontaneous onset of labor. There was no significant difference of values between primigravidas and multigravidas, male and female babies, or normal and preeclamptic pregnancies. There was no significant change in mean cord plasma cortisol values with advancing gestational age, after the 33rd week. It is conceivable that spontaneous labor in humans may be preceded by a release of cortisol into the fetal circulation, and when a critical "parturient" level is reached labor becomes established.     

Effects of early cyclophosphamide treatment on lymphoid organs and its immune response in ducks

Cyclophosphamide treatment of newly hatched White Pekin ducks significantly reduced the weight of their lymphoid organs and almost completely eliminated the formation of bursal lymphoid follicles at one week of age. There after the thymus and spleen of these ducks completely recovered in weight at 7 weeks of age. The bursa, however, retained its light weight and morphological defects, such as the absence of lymphoid follicles. The specific antibody producing-capability to Salmonella pullorum was also eliminated. The total dosage of cyclophosphamide was smaller than that employed in chickens, which makes effective chemical bursectomy in ducks possible.     

The mode of onset of rheumatoid arthritis and seasonal variations

The aim of the study was to establish age and sex distribution, seasonal variations, and mode, of onset in a sample of patients with rheumatoid arthritis. One hundred eighty nine patients (146 women and 43 men), whose age ranged from 18 to 77 yrs. (mean age 49.1, SD 12.93) were included in the survey. In majority of patients the disease started between 31-50 years, whereas in the age group from 21-30 it occurred more frequent in women, and in the age group from 51-60 in men. The onset of rheumatoid arthritis was in almost equal proportions acute or insidious, regardless sex. No difference was found concerning onset of the disease and seasonal variations. However there was a statistically significant correlation between mode of the onset and seasonal variations (P < 0.05). Rheumatoid arthritis started abruptly more often in springtime, and more insidiously in autumn, whereas in summer and winter there was an equal number of patients with acute or insidious onset of the disease.     

Effects of combined treatment with recombinant bovine somatotropin and immunization with live oocysts on performance of broiler chicks raised in coccidia-seeded floor pens

In our laboratory, preliminary studies have indicated that recombinant bovine somatotropin (rbST) can stimulate protective immunity against coccidia infection. A floor pen trial on coccidia-seeded litter was run to further test its activity as an adjuvant during immunization of chicks with a live oocyst vaccine. Five hundred day-old male broiler strain chicks were randomly assigned to five experimental Treatments: 1, medicated controls; 2, unimmunized, not treated with rbST; 3, unimmunized, rbST-treated; 4, immunized, not treated with rbST; 5, immunized, rbST-treated. Each treatment consisted of four pens of 25 chicks each. At the end of the growout period (7 wk), the chicks in Treatment 1 (medicated controls) had the highest mean BW, but mean BW of chickens in Treatment 3 (rbST treatment only) were not significantly less. On the other hand, the mean weights of chicks in Treatments 4 (immunized only) and 5 (immunized plus rbST) were significantly reduced, and not different from those of the untreated chickens (Treatment 2). However, when challenged at 3 wk, the chicks in Treatment 5 had a mean combined total lesion score that was significantly lower than that from Treatment 3, indicating that they had developed a higher degree of specific immunity, but of the expense of weight gain. The results suggest that rbST has a potential for use as an adjuvant with live oocyst vaccination, but that the ratio between rbST dose and numbers of oocysts in the live vaccine needs to be carefully controlled.     

Hematocrit values in weight-selected and relaxed lines of White Rock chickens

Hematocrits (PCV) were measured at 29 and 106 d of age (PCV1 and PCV2, respectively) in male and female White Plymouth Rocks. Four lines were used, two of which had undergone 40 generations of divergent selection for 8-wk BW (HWS, LWS), and two respective sublines (HWR, LWR), in which selection had been relaxed for five generations. At both ages, males and females did not differ for PCV in lines HWR, LWR, and LWS. For line HWS there was an age by sex interaction that resulted from an age effect for males but not for females, and from a sex effect at each age. At both ages, PCV was higher for the HW than the LW lines. Initially, there was no difference between the selected and their respective relaxed lines, but by 106 d, HWR chickens had a higher PCV than HWS chickens. In lines HWR and LWR, PCV increased with age. There was a negative correlation in HWS males for PCV1 with 28 and 56 d BW. The HWR males also had a negative correlation for PCV1 with BW at 28 d, but not between PCV2 and BW. The correlation for PCV1 with PCV2 was high and positive for HWR males and females.