Immunonblot technique for early diagnosis of sheep scab.
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Animals↗
Biomedical subjects
M G Varma
Publications and source records attributed to M G Varma.
Local excision of rectal carcinoma.
HYPOTHESIS: Selected clinicopathologic characteristics of locally treated rectal cancers are predictive of recurrence. DESIGN: Case series review with median follow-up of 6 years. SETTING: University medical center. PATIENTS: Fifty-eight patients with rectal cancer who underwent local excisions from February 1, 1982, to December 31, 1998. MAIN OUTCOME MEASURES: Local and distant recurrence rates and overall survival. RESULTS: Overall local recurrence rate was 14% (8 patients). There were no local recurrences among patients treated with chemotherapy or radiation. Of patients not treated, local recurrence rates were 33%, 5%, 45%, and 25% for T0, T1, T2, and T3 tumors, respectively. No clinicopathologic factor predicted local recurrence. Two patients developed distant recurrence. Overall survival was 98%, 93%, and 84% at 1, 3, and 5 years, respectively. CONCLUSION: In selected patients, outcomes for local excision combined with additional therapy may be equivalent to those for radical resection.
Adenocarcinoma↗
Antigens of the sheep scab mite Psoroptes ovis.
Sheep scab caused by the mite Psoroptes ovis (Hering) is a highly contagious disease of sheep. As a first step in developing a mite-derived vaccine for controlling the disease, the soluble antigens in mite extracts which induce an immune response in sheep were identified by electrophoretic and immunoblotting techniques. At least 22 proteins were present in P. ovis extracts as revealed by Coomassie Blue staining. Mite-infested sheep serum recognised six antigenic bands in the extracts with approximate relative molecular weights ranging from 12 to 183 kDa. A deeply staining band at 31.2 kDa and another at 41.8 kDa are of particular diagnostic value. Immunoblotting studies showed that there was no cross reactivity between P. ovis and two other ectoparasites of sheep in the UK, the sheep louse Bovicola ovis (Schrank) and the sheep tick Ixodes ricinus L.
Animals↗
Resistance and cross-resistance in rabbits to adults of three species of African ticks (Acari: Ixodidae).
Resistance to Rhipicephalus appendiculatus, Amblyomma variegatum and Amblyomma hebraeum was investigated in the laboratory by infesting rabbits with adults of each of the three species followed by homospecific or heterospecific secondary infestations. Significantly lower female engorged weights and egg mass weights were taken as evidence of protective immunity. Following a single infestation with adults, rabbits developed homospecific protective immunity (resistance) to only R. appendiculatus and A. hebraeum; primary infestation with A. variegatum did not protect against secondary infestation with the same species. There was no cross-resistance (heterospecific protective immunity) between the species except for one-way protection between R. appendiculatus and A. variegatum; primary infestation with R. appendiculatus protected against secondary infestation with A. variegatum, but not vice versa. The results from ELISA did not indicate any correlation between serum antibodies to soluble antigens from salivary gland extracts and protective immunity. Post-infection sera from rabbits infested with each of the three species reacted strongly to their respective salivary gland extracts. Despite the high reactivity of A. variegatum serum with salivary gland antigens from all three species, A. variegatum-infested rabbits did not show any homospecific or heterospecific-immunity; on the other hand, although R. appendiculatus serum did not react positively to A. variegatum antigens, infestation with R. appendiculatus protected against a subsequent A. variegatum infestation.
Animals↗
The role of Rhipicephalus appendiculatus and R. evertsi evertsi males in inducing resistance in laboratory animals: preliminary studies.
Guinea-pigs infested with male ticks of the species Rhipicephalus appendiculatus, and rabbits infested with R. evertsi evertsi, acquired immunity to conspecific female ticks. The hosts were first infested with male ticks and thereafter were challenged with males and females of the same species. The mean weight of the engorged females of R. appendiculatus fed on guinea pigs previously infested with male ticks was 509.0 (+/- 41.4) mg compared with that of females fed on control guinea pigs (651.2 +/- 31.8 mg). Similar weight differences were observed for R.e. evertsi females which fed on rabbits previously infested three times with male ticks. The mean weight of the female ticks which fed on these rabbits was 520.1 (+/- 29.8) mg compared with 640.7 (+/- 30.2) mg of R.e. evertsi females which fed on control hosts. The concentration of gammaglobulins in the sera of rabbits was monitored at various intervals after the first infestation. It was found, for the first time, that infestation of laboratory animals with male ticks conferred immunity, but to a lesser degree than infestation with both sexes. It was also shown that the level of gammaglobulins increased from 3.4 +/- 0.28 g l-1 to 7.3 +/- 0.24 g l-1 in sera of rabbits hosts as a result of the feeding activity of males, but to a lesser extent than in sera of rabbits on which both sexes had fed (10.8 +/- 2.4 g l-1).
Animals↗
The conditions required for the maintenance of Onchocerca lienalis microfilariae in vitro.
Microfilariae of the bovine parasite Onchocerca lienalis were maintained in vitro using a tick cell line as a feeder layer, and under the conditions provided would develop to the sausage stage. A number of media supported this achievement with CMRL 1066 producing the highest yields, particularly when used in conjunction with either medium 199, HAM's F-12, RPMI 1640 or Mark's M20. The addition of inactivated foetal calf serum (iFCS) suppressed development; on the other hand, the addition of tryptose phosphate broth (TPB) enhanced it. The pH range of the medium preferred by the developing worms was 7.35-7.85, and the most favourable osmolality lay in the range 360 to 390 mosM/kg. Insect-derived hormones did not improve yields of developed larvae nor promote moulting to the second larval stage. The culture conditions described in this work, which favour parasite survival and development, provide further insights into the physiological requirements of filariae as well as guide lines to achieving successful in vitro maintenance of Onchocerca sp. A morphological examination of the developing larvae was carried out at electron microscopical level.
Animals↗
Immunization of guinea-pigs against Rhipicephalus appendiculatus adult ticks using homogenates from unfed immature ticks.
Guinea-pigs immunized with homogenates of unfed larvae and nymphs of the tick Rhipicephalus appendiculatus developed significant levels of protective immunity to infestation with adults of this species. The mean engorged weight of female ticks feeding on immunized animals (181.96 +/- 05.63 mg and 170.11 +/- 11.54 mg) was reduced by an average of 46% and 51%, respectively, compared to that of female ticks feeding on control guinea-pigs, although in some individual animals the reduction was as high as 86%; the mean egg mass weight was also significantly reduced. Electrophoretic separation of the homogenates followed by immunostaining with post-infestation sera revealed several antigen bands common to all stages. Two bands of 36,500 and 23,000 molecular weight (MW) were recognized in all homogenates by post-adult infestation serum, but not by post-larval or post-nymphal infestation sera, suggesting that these may be antigens specifically involved in feeding by adult ticks, and are either not presented to the host's immune system or presented only in minimal amounts during feeding by immature stages. Sera from animals immunized with the homogenates did not recognize either of these antigens. Post-immunization sera did, however, stain two bands of 84,000 and 60,000 MW in the homogenates which were not recognized by post-infestation sera.
Animals↗
Delayed-type hypersensitivity test for assessing tick-immune status of cattle in Zambia.
Delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of Tonga calves in Zambia. The antigen used in the tests was a homogenate of unfed nymphal Rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female R appendiculatus. There was a significant negative correlation between the intensity of the reactions and the total number of ticks (Amblyomma variegatum, R appendiculatus, Hyalomma truncatum, Boophilus decoloratus and Rhipicephalus species) on the animals.
Animals↗
Changes in the concentration of globulins in naive guinea pigs during feeding by the immature stages of Rhipicephalus evertsi evertsi (Acari: Ixodidae).
The weight of Rhipicephalus evertsi evertsi Neumann nymphs, which as larvae and nymphs completed the entire blood meal on the same individual guinea pig, was significantly lower than the weight of those that as larvae and nymphs fed on two separate naive hosts. Nymphs of the latter category spent 1 wk (from unfed larvae to unfed nymphs) on one animal before their transfer to the second host to complete the blood meal. The albumin concentration of the host blood decreased and was related to the time that the immature ticks spent on the hosts. The albumin/globulin ratio also decreased. The alpha 1 globulin fraction increased soon after the guinea pigs were infested with ticks. No further changes in the levels of the alpha 1 globulin fraction were observed with time. The concentration of serum beta globulins increased only in guinea pigs infested with immature ticks for the entire larval and nymphal feeding period. A second infestation of those guinea pigs with larvae of R. e. evertsi resulted in further increases in the levels of serum beta globulins. The relationships among serum beta globulin levels, the weight of engorged nymphs, and host immunity are discussed.
Animals↗
Resistance and cross-resistance in guinea-pigs and rabbits to immature stages of ixodid ticks.
Infestation of guinea-pigs and rabbits with larvae of any one of five species of ticks, Rhipicephalus appendiculatus Neumann, Rhipicephalus evertsi evertsi Neumann, Amblyomma hebrauem Koch, Amblyomma variegatum Fabricius and Ixodes ricinus L., conferred resistance in the animals when exposed to subsequent infestations with the same tick species. Resistance to infestations by other tick species was not observed.
Animals↗
Expression of acquired immunity to immature stages of the tick Rhipicephalus evertsi evertsi by rabbits and guinea-pigs.
Acquired immunity in guinea-pigs and rabbits to immature stages of the two-host tick Rhipicephalus evertsi evertsi Neumann was demonstrated. Repeated infestations of both hosts with larvae resulted in a significant reduction in the weight of later engorged nymphs. A sharp decline in the numbers of nymphs which successfully fed on both hosts was also observed. This study provides evidence for a gradual decrease in the mean weight of engorged nymphs towards the end of the detachment period suggesting that, in two-host ticks, the onset of nymphal feeding acts as an immune booster in a host already primed by the larval feed and that this results in a reduced feeding performance.
Animals↗
Examination of the immunological relationships between flaviviruses using yellow fever virus monoclonal antibodies.
Monoclonal antibodies prepared against vaccine strains of yellow fever (YF) virus were initially characterized by fluorescence microscopy of Vero cells infected with YF virus strain 17D. When similarly tested against representatives of all flavivirus subgroups, the antibodies produced a wide spectrum of reactions ranging from the monospecific to the broadly cross-reactive; at least five antigenic domains in the YF virus envelope glycoprotein were identified. Monoclonal antibodies differentiated between YF virus vaccine strains (17D, 17DD, FNV), wild-type viruses and plaque variants selected from a 17D pool. One isolate from a patient with YF was antigenically similar to the Brazilian vaccine strain 17DD. Several of the antibodies reacting with the YF viral envelope glycoprotein in biological tests identified the 54K envelope glycoprotein; 45K and 26K polypeptides in YF 17D virus-infected cells were also identified by radioimmunoprecipitation and polyacrylamide gel electrophoresis. Neither of these polypeptides was found in uninfected cells. They may represent short-lived precursors of the 54K protein, post-translational cleavage or breakdown products. Other antibodies reacted with a 48K polypeptide in virus-infected cell lysates. This may be the non-structural NV3 protein described for YF virus. Its appearance on the surface of unfixed infected cells, but not on released virions, was demonstrated by fluorescence microscopy.
Animals↗
The effect of Trypanosoma congolense infection on acquired immunity to the tick Rhipicephalus appendiculatus.
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Animals↗
Immunofluorescence studies on the antigenic interrelationships of the Hughes virus serogroup (genus Nairovirus) and identification of a new strain.
Titrations of hyperimmune antisera by indirect immunofluorescence using each virus of the Hughes serogroup (Hughes, Zirqa, Punta Salinas, Soldado and Farallon) demonstrated their individual antigenic identities. Furthermore, an antigenically related virus, designated Puffin Island (PI) virus, was shown both by indirect immunofluorescence and by neutralization in XTC cells to be distinguishable from the other viruses. These viruses readily established persistent infections in Vero cells after producing only moderate cytopathic effects. Treatment of persistently infected cultures with either fluorodeoxyuridine or bromodeoxyuridine made no significant difference to the percentage of immunofluorescent cells. Attempts to demonstrate haemagglutination by Zirqa virus were unsuccessful.
Antigens, Viral↗
Monoclonal antibodies to Sindbis virus glycoprotein E1 can neutralize, enhance infectivity, and independently inhibit haemagglutination or haemolysis.
Two monoclonal antibodies raised against Sindbis virus were shown to be specific for the envelope glycoprotein E1 by radioimmunoprecipitation (RIP). They had a number of contrasting biological properties. One of them was capable of neutralizing virus infectivity and inhibiting haemagglutination, while the other had no significant neutralizing or haemagglutination-inhibiting capability, but did inhibit virus-mediated haemolysis. Both monoclonal antibodies could enhance virus infectivity of Fc receptor-bearing macrophage-like cells when present at suitable dilutions.
Animals↗
The ultrastructures of dengue type 1 virus in the Aedes pseudoscutellaris mosquito cell line.
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Aedes↗
Investigation of the ecology of Soldado virus on Puffin Island, North Wales.
The prevalence of Soldado (SOL) virus and SOL virus antibodies was investigated on immature sea birds and the argasid tick Ornithodoros (Alectorobius) maritimus collected on Puffin Island, North Wales. No SOL virus was recovered from 133 bird sera, but 2 of the birds exhibited neutralizing antibodies against SOL virus. Nine of 27 tick pools (226 individuals) and 34 of 173 ticks tested individually proved to be infected with SOL virus.
Animals↗
Isolation of dengue viruses in mosquito cell cultures under field conditions.
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Aedes↗