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Biomedical subjects

R A Matthews

Publications and source records attributed to R A Matthews.

15 recordsLinked to original sources
PubMed1999

Ichthyophthiriasis in carp Cyprinus carpio: infectivity of trophonts prematurely exiting both the immune and non-immune host.

Ichthyophthirius multifiliis exposed to naturally immunised carp established short-term infections, the majority of parasites actively emerging within 2 h of entering the epidermis. A small, but significant, number of these expelled parasites were shown to retain theront-like properties with the capacity to directly re-invade a further fish host. Infectivity fell rapidly with time in the host and was comparable to that of trophonts of a similar age artificially induced to emerge from non-immune hosts with the aid of MEM (minimal essential medium). Trophonts recovered with MEM from immune carp 2 to 8 h post infection rarely established infections upon exposure to susceptible new hosts and no infections resulted from older trophonts recovered after 8 to 24 h exposure; older trophonts, however, represented only a small percentage of the original parasite population. A low level of infectivity was recorded in trophonts collected with the aid of MEM from non-immune carp after up to 24 h of infection. The results are discussed in relation to theront transformation and evasion of the host immune response.

Animals↗
PubMed1995

Quality team approach in evaluating three automated hematology analyzers with five-part differential capability.

Three modern hematology analyzers (Abbott Cell-Dyn 3000, Coulter STKS, and Sysmex NE-8000) with high throughput and 5-part differential capability were evaluated using a protocol designed by a quality team. Effective use of the team process to evaluate instrumentation empowers laboratory personnel to share in decision-making activities, improves job satisfaction, and produces the best purchasing decision. Instruments were compared using a combination of statistical analysis and written evaluations provided by team members. Tools and concepts from this study provide a comprehensive model for an effective multi-instrument evaluation.

Automation↗
PubMed1994

A standardized method for the in vivo maintenance of Cryptocaryon irritans (Ciliophora) using the grey mullet Chelon labrosus as an experimental host.

Experimental primary infections with Cryptocaryon irritans were successfully established in mullet following exposure to theronts and maintained for up to 34 successive cycles in this host. Fish were exposed to measured numbers of theronts collected within 4 hr of excystment. Free-swimming trophonts and reproductive cysts were maintained in wells of tissue culture plates containing sterilized seawater and subjected to a photoperiod of 12 hr light:12 hr dark. Excystment was found to be asynchronous over a period from 84 hr to 35 days. The procedure provided at least a 10-fold yield of parasite material per cycle of transmission.

Animals↗
PubMed1993

Localized leucocyte response to Ichthyophthirius multifiliis establishment in immune carp Cyprinus carpio L.

O-group carp (Cyprinus carpio) which had been immunized against Ichthyophthirius multifiliis by controlled infections were challenged by topical application of theronts to the caudal fin. The parasites which established were examined ultrastructurally, and host leucocyte responses were compared with those observed in primary infections. In the primary exposure group eosinophils and (to a lesser extent) basophils were the predominant cells infiltrating infection sites. In contrast, parasite development in immunized fish initiated localized leucocytic infiltrations which were dominated by eosinophilic granular cells (EGCs) and basophils. Greater localized phagocytosis was recorded in immunized fish by neutrophils, macrophages and resident epidermal filament cells. In vitro studies indicated that pronephric leucocytes from immunized fish displayed enhanced non-specific phagocytosis. In the skin, leucocytes were observed in close proximity to the trophozoite surface in both immunized and primary exposure fish, often undergoing lysis and release of cellular contents. However, there was no evidence of active cell adherence nor of any cell-mediated damage incurred to the parasite in either case. These observations are discussed in relation to the possible role of leucocytes in mediating pathogenesis and immune responses.

Animals↗
PubMed1993

Cryptocotyle lingua in mullet, Chelon labrosus; significance of metacercarial excretory proteins in the stimulation of the immune response.

'O' group mullet, Chelon labrosus, were experimentally infected with Cryptocotyle lingua (Heterophyidae) by tail dip in a suspension of cercariae. Metacercariae were excised after 1 and 24 hours and prepared for TEM and post-embedding immunogold labelling. Antisera to cercariae of C. lingua were raised in adult mullet by natural infection via the skin and by intra-peritoneal injection of sonicate. The membrane-bound vesicles within the syncytial lining of the metacercarial excretory vesicle were found to be intensely antigenic with both antisera; the epidermal secretory bodies type 5 within the cystogenous glands gave a positive response. Penetration gland contents were not found to be antigenic with either antiserum. Discharge of the membrane-bound vesicles coinciding with both the reorganization of the lining of the metacercarial excretory vesicle and with cyst wall formation appears to be of significance in the initiation of the host immune response. That the term 'excretory vesicle' in Digenea may be a misnomer is discussed in the light of current information regarding the wide range of functions attributed to this structure.

Animals↗
PubMed1991

Lecithochirium furcolabiatum (Jones 1933), Dawes 1947: the miracidium and mother sporocyst.

Experimental infections of the marine topshell Gibbula umbilicalis with Lecithochirium furcolabiatum (Digenea: Hemiuroidea) have allowed the development of a model system which will enable further studies of the molluscan host response. The long-lived intertidal prosobranch host is easily maintained in the laboratory, and experimental infection rates of 98% were consistently achieved. The miracidium and mother sporocyst have been studied at both light and ultrastructural levels, providing the first account of the morphology of these stages in Hemiuridae. The ingested egg hatches within the host intestine, treatment with L-cysteine and alkaline pH stimulating miracidial emergence in vitro. The general body surface of the miracidium is devoid of spines or cilia, the latter being restricted to four plates near the anterior extremity. The miracidium swims actively prior to penetration of the gut wall, the sporocyst being released from the miracidial epidermal coat within the haemocoel. Within 5 weeks of infection, the filamentous mother sporocyst contains 1 to 3 oval germ balls, daughter sporocysts being recorded free within the digestive gland haemocoel 7 weeks later. Twenty three weeks after ingestion of eggs, the daughter sporocyst extends into the host gill filaments, containing cystophorous cercariae ready for emergence.

Animals↗
PubMed1989

Computer aided manual leucocyte differential counting.

Over the last two decades numerous ways have been devised for automating the recording of the results of the leucocyte differential, ranging from computer-readable cards to very costly automated cell counters. The growing availability of inexpensive personal computers makes it possible to improve the counting and reporting of the manual differentials which still account for the bulk of these counts. This report describes the development of a system using a personal computer, either as a standalone device or integrated into a larger laboratory system, to assist the technologist in performing the differential count and in completely describing the results. It permits complete flexibility in function assignments and in information structuring to match the constraints of the laboratory host computer system.

Clinical Laboratory Information Systems↗
PubMed1986

Immunosuppression of carp (Cyprinus carpio L.) to ichthyophthiriasis using the corticosteroid triamcinolone acetonide.

The immune response of juvenile mirror carp (Cyprinus carpio L.) has been investigated in relation to protective immunity and immunosuppression to the disease ichthyophthiriasis. Protective immunity was induced by exposing juvenile carp to approximately 2,000 theronts per fish for 3 hours at a concentration of approximately 80 theronts cm-3 in dechlorinated water pH 7.0-7.2, 20 +/- 2 degrees C in the dark, on three separate occasions of 14 day intervals. Following each exposure, re-infection was prevented by transferring fish to clean aquaria twice daily from day 5-10. Fish were challenged 4 weeks following exposure to the third immunising infection with a potentially lethal dose of approximately 8,000 theronts per fish for 3 hours at a concentration of approximately 320 theronts cm-3. All immunised fish survived although 19% showed initial signs of invasion, the parasites in these instances being confined to periphery of fins. Mortalities of 100% were recorded in non-immunised controls, first deaths occurring 5 days after challenge. Fourteen days following challenge, immune fish received one of the following treatments; intraperitoneal injection of the corticosteroid triamcinolone acetonide at a dose of 200 micrograms g-1 body weight, intraperitoneal injection of 0.85% saline or left untreated; non-immunised fish were subjected to similar procedures. On challenge 6 days later, all fish developed heavy infection with up to 100% mortalities with the exception of immunised fish administered saline or left untreated. Repeat experiments gave comparable results. The results indicate that immunosuppression can be induced by administration of high levels of synthetic corticosteroid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

The cellular proliferative response, humoral antibody response, and cross reactivity studies of Tetrahymena pyriformis with Ichthyophthirius multifiliis in juvenile carp (Cyprinus carpio L.).

The immune response of 10-12-week-old juvenile carp to T. pyriformis [CCAP 1630/w, 1939 (w)] was investigated. The humoral antibody response following one and two intraperitoneal injections of whole live T. pyriformis (protein concentration of 25 micrograms/g body weight), separated by an interval of 4 weeks, was monitored over 12-16 weeks. Peak antibody titres were detected 6 weeks following antigen administration. Antibody titres were elevated following the second injection, and relatively high levels were still maintained by week 16. Proliferative responses measured by autoradiography following intraperitioneal injection of methyl 3H thymidine (1-2 microCi/g body weight) were recorded in the pronephros, opisthonephros, and spleen at weekly intervals for 4 weeks following each injection of T. pyriformis. Immunised fish had higher counts than nonimmunised controls, with the greatest counts occurring at 2 and/or 3 weeks following one injection of antigen and 2 weeks following two injections. Activity was recorded prior to peak antibody production with the pronephros and opisthonephros having greater proliferative responses than the spleen. Cross antigenicity studies to examine protection of carp against I. multifiliis following administration of T. pyriformis, showed little evidence in support of protection using this strain of T. pyriformis. Further, antisera raised in either carp, rabbits, or rats failed to show any cross antigenicity between these two species of protozoa.

Animals↗