Search PubMed⌕ Search

Biomedical subjects

S M Carroll

Publications and source records attributed to S M Carroll.

At least 55 records · Page 3Linked to original sources
PubMed1985

Scanning electron microscopy of Ancylostoma ceylanicum and its site of attachment to the small intestinal mucosa of the dog.

The relationship between the hookworm Ancylostoma ceylanicum and the host intestinal mucosa in situ has been examined by using an in vivo fixation technique and scanning electron microscopy. Heads of the adult worms were buried deeply in the mucosa of the dog's small bowel. At some sites of attachment there was severe atrophy and ulceration of the immediately surrounding villi. Superficial deposits of fibrillar material with many enmeshed erythrocytes were associated with these attachment sites. When adult worms became removed after fixation, large numbers of erythrocytes could be seen at the base of the ulcers. Examination of the morphological details of adult A. ceylanicum revealed the characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functi characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functi characteristic mouthparts of large outer ventral teeth and smaller inner teeth. The distance between adjacent transverse cuticular striations was measured as 5.2 microns. The wide separation of the externolateral ray from the closely related mediolateral and posterolateral rays was illustrated together with the functional relationship of male and female copulating worms.

Ancylostoma↗
PubMed1985

Ancylostoma ceylanicum: immunization with soluble worm extract and responses to challenge infection of dogs.

When dogs were immunized with soluble extract of adult Ancylostoma ceylanicum antigen, they were partially resistant to challenge infection in this model of human hookworm infection. Two immunizing doses, each of 1 mg protein suspended in Freund's complete adjuvant, were administered to one group of animals 1 and 3 weeks prior to infection with 5000 larvae. When compared with control dogs given the same infective dose, fecal egg excretion and intestinal adult worm burden in the immunized animals were reduced by 59 and 74%, respectively. Infection had no significant effect on hemoglobin concentrations, mean red cell volumes, total white cell counts, platelet levels, or spontaneous and phytohemagglutinin-induced lymphocyte transformations in both control and immunized animals. Both groups developed an eosinophilia, and lymphocytes from the immunized dogs responded transiently to stimulation with both larval and adult worm antigens. Specific IgM antibodies were transitory in both groups of dogs following infection. IgG antibodies developed significantly 2 weeks after infection in the immunized group; however, they did not appear until 4 weeks after infection in the control group. Both groups developed IgA antibodies 1 week after infection. They were maintained in the control dogs, in contrast to the levels in immunized animals which subsided rapidly 4 weeks after infection. Therefore, when animals are injected with soluble adult worm antigen prior to infection, specific protective immunity is acquired.

Ancylostoma↗
PubMed1985

Resistance of dogs to reinfection with Ancylostoma ceylanicum following anthelmintic therapy.

A model of human hookworm infection has been developed which shows that dogs with chronic hookworm infection are considerably resistant to reinfection one month after the termination of the primary infection with anthelmintics. Challenge and control dogs were infected with 1,800 larvae and the infection was followed for six weeks. When compared with control dogs, faecal egg excretion and intestinal adult worm burdens in challenge dogs were reduced by 85% and 77%, respectively. Infection had no significant effect on haemoglobin concentrations, total white cell counts, platelet levels or spontaneous and phytohaemagglutinin-induced lymphocyte transformations in both control and previously infected dogs. Both groups of dogs developed an eosinophilia and lymphocytes responded transiently to stimulation with both larval and adult worm antigens, although there were no significant differences between the two groups of animals. Specific IgM antibodies were transient in both groups of animals following infection. Specific IgG antibodies were present at high levels before infection in challenge dogs when compared with control dogs, and fell transiently after challenge; three weeks after infection, IgG antibodies appeared in the control animals and titres continued to rise during the period of observation. Challenge dogs also developed specific IgA antibodies three weeks after infection, and these remained at high levels, but these antibodies were not detected in control dogs. Thus, dogs infected with this strain of the hookworm, Ancylostoma ceylanicum, which has been shown to infect man, develop functional protective immunity. These findings improve prospects for vaccine development.

Ancylostomiasis↗
PubMed1985

Differential infection of receptor-modified host cells by receptor-specific influenza viruses.

Influenza viruses of contrasting receptor specificity have been examined for their ability to infect receptor-modified MDCK cells containing sialyloligosaccharide receptor determinants of defined sequence. Cells were treated with sialidase to remove sialic acid and render them resistant to infection and were then incubated with sialyltransferase and CMP-sialic acid to restore sialic acid in the SA alpha 2,6Gal or SA alpha 2,3Gal linkages. The viruses A/RI/5 + /57 and A/duck/Ukraine/1/63, previously shown to exhibit preferential binding of SA alpha 2,6Gal and SA alpha 2,3Gal linkages, respectively, were found to exhibit differential infection of the receptor-modified cells in accord with their receptor specificity. Coinfection of SA alpha 2,3Gal derivatized cells with a mixture of the two viruses resulted in selective propagation of the SA alpha 2,3Gal-specific A/duck/Ukraine/1/63 virus. The results demonstrate the potential for cell surface receptors to mediate selection of receptor-specific variants of influenza virus.

Adsorption↗
PubMed1984

The anticoagulant effects of the hookworm, ancylostoma ceylanicum: observations on human and dog blood in vitro and infected dogs in vivo.

Extracts of adult Ancylostoma ceylanicum prolonged the prothrombin time (PT) and partial thromboplastin time with kaolin ( PPTK ) of both human and dog plasmas in vitro. Excretory/secretory (E/S) products of these worms had similar effects while larval extract prolonged the PTTK only. Thus, the anticoagulant activities of this parasite are dependent upon the stage of the worm's life cycle. Collagen- and ADP-induced platelet aggregation were inhibited by adult and larval extracts. When the peripheral blood and bleeding times of dogs with varying worm burdens were examined, the only abnormality was shortening of the PTTK in the most heavily infected animals. Homogenates of dog small bowel subjacent to adult hookworms prolonged the PT of dog plasma and electron microscopical examination of this tissue revealed aggregation of platelets in blood venules without fibrin deposition. Thus, this study provides evidence that the anticoagulant properties of hookworms may have biological significance in infected animals.

Ancylostoma↗
PubMed1984

Transmission electron microscopical studies of the site of attachment of Ancylostoma ceylanicum to the small bowel mucosa of the dog.

The host-parasite interaction at the site of attachment of the adult hookworm, Ancylostoma ceylanicum, to the small bowel mucosa of the dog has been examined by transmission electron microscopy. The lamina propria around the heads of the worms showed intense infiltration with neutrophilic and eosinophilic leucocytes, and plasma cells were also prominent. Erythrocytes were extravasated within the lamina propria while the portions of mucosa engulfed into the buccal cavities of the worms were necrotic and included aggregates of collagen fibres. Within the lumina of the worms were erythrocytes in varying stages of lysis together with other necrotic debris. The mucous membrane adjacent to the heads of the worms was ulcerated while more distant enterocytes were small, distorted and displayed various degrees of microvillar loss. Many mucosal blood vessels had platelet aggregates within their lumina but no fibrin deposition was observed. Vessels were often seen in the bases of the ulcers and were prone to rupture. Erythrocytes and leucocytes were seen in the dog intestinal lumen in close proximity to the bodies of the worms.

Ancylostoma↗
PubMed1984

Parasitological, hematologic, and immunologic responses in acute and chronic infections of dogs with Ancylostoma ceylanicum: a model of human hookworm infection.

A model of human hookworm infection has been defined with a strain of Ancylostoma ceylanicum that is known to be infective for humans. In the first experiment, dogs were infected with between 150 and 12,150 filariform larvae and followed up for six weeks. A direct relation was found between the size of infecting dose, fecal egg excretion, intestinal adult worm burden, and worm distribution in the bowel. Dogs with heavy infection developed bloody diarrhea and iron-deficient anemia. In the second experiment, dogs infected with 2,000 larvae excreted ova until autopsy 36 weeks after infection. Normocytic anemia and blood eosinophilia coincided with maximal egg excretion. Transitory lymphocyte stimulation was seen with adult worm antigen. The specific IgM antibody response was transient, but IgG antibodies persisted indefinitely. Marked skin immediate hypersensitivity and Arthus (but no delayed) hypersensitivity reactions were seen to injected larval and adult antigens. Thus, dogs develop both hookworm disease and chronic infections similar to those seen in humans.

Acute Disease↗
PubMed1984

Plasma somatomedin activity after injury in man and its relationship to other hormonal and metabolic changes.

Plasma somatomedin activity was measured in 12 patients who had sustained non-fatal musculo-skeletal injuries. It was depressed for 2-3 d after injury, but this depression bore no relationship to the catabolic response to injury which, as judged by urinary nitrogen excretion, was maximal at about one week. The depression of somatomedin activity may have been related to the high plasma cortisol concentrations observed during the first few days after injury. Plasma growth hormone concentrations were high acutely after injury but rapidly returned to normal. The changes in plasma somatomedin activity were thus unrelated to those in growth hormone, but were very similar to those in plasma insulin concentrations. A marked positive relationship was observed between plasma insulin concentrations and urinary nitrogen excretion, indicating unresponsiveness of protein metabolism to the normal anabolic effects of insulin. The study showed, however, that this was not as a result of low somatomedin activity.

Adolescent↗
PubMed1984

Kinetics of intestinal lamina propria mast cells, globule leucocytes, intraepithelial lymphocytes, goblet cells and eosinophils in murine strongyloidiasis.

The changes in numbers of 6 cell populations in the intestine of mice at various intervals after primary and challenge infections with Strongyloides ratti have been quantified. The number of lamina propria mast cells increased 8 days after primary infection and reached a peak at 12 days. After secondary infection, there was a transient fall in mast cell numbers followed by a slow increase. Globule leucocytes showed a similar trend early in the primary infection and had reached normal levels after 28 days. After challenge infection, there was an early and rapid increase in their numbers. Granular intraepithelial lymphocytes did not alter significantly during the first 14 days, but were significantly greater 28 days after primary infection; they did not vary significantly after challenge infection. However, numbers of non-granular intraepithelial lymphocytes increased 10 days after infection, were elevated prior to the secondary infection at 28 days, then declined in numbers nearly 2 weeks after challenge infection. Goblet cells increased significantly 12 days after primary infection then declined rapidly. After challenge infection, there was an accelerated increase in numbers. Eosinophil numbers increased 4 days after infection, reached a peak at 12 days and then declined. After challenge infection, there was an augmented and accelerated increase in eosinophil numbers followed by rapid decline. The role of the various cells types in host defences against worms or in containment of the inflammatory responses evoked by these parasites are discussed.

Animals↗
PubMed1984

Investigation of the haemolytic effects of Ancylostoma ceylanicum: observations on infected dogs in vivo and human and dog blood in vitro.

Investigations into the probable role of haemolysins in the causation of hookworm anaemia have been undertaken in living infected dogs. Secondly, the effects of living hookworms and various worm products on erythrocytes in vitro have been assessed. In dogs infected with varying numbers of A. ceylanicum, severe microcytic anaemia developed in the most heavily infected animals six weeks after infection. Erythrocytes from the latter animals showed significantly greater autohaemolysis in the presence of added glucose. When serum bilirubin and methaemalbumin, plasma haemoglobin, urinary urobilinogin and osmotic fragility of their red cells were measured, however, no evidence of haemolysis was detected. Erythrocytes from these animals appeared normal under scanning electron microscopy. In in vitro studies varying concentrations of adult worm extract had no effect on the haemolysis of either dog or human erythrocytes in the presence or absence of glucose nor on their mechanical fragility. There was no increase in 51Cr release from dog or human labelled red cells when incubated with either adult worm extract or excretory/secretory products of worms. Living adult worms caused an increase in 51Cr release from human but not dog labelled erythrocytes. Thus, the role of haemolysins in the genesis of hookworm anaemia is minimal.

Ancylostoma↗
PubMed1983

Diarrhoea associated with Clostridium difficile in a hospital population.

The incidence of disease associated with Clostridium difficile was investigated in a general hospital population over a period of six months. In 26 (14.5%) of 179 patients studied, C. difficile was either isolated or faecal cytotoxin was detected. The incidence of other enteropathogenic bacteria, except Aeromonas hydrophila, was low. Faecal cytotoxin was not detected in nine patients (35%), and non-cytotoxigenic strains of C. difficile were isolated from these patients. In seven patients, a selective broth was required to isolate C. difficile, suggesting their presence in low numbers. Although some C. difficile diarrhoeal disease which was not associated with antibiotic therapy was recorded, prior exposure to antibiotic agents still appears to be the major predisposing factor in this population. Faecal cytotoxin detection, sigmoidoscopy, and rectal biopsy were not reliable investigations for disease associated with C. difficile; hence, we advocate increased emphasis on isolation of the causative organism. Routine culturing for C. difficile in a hospital population appears to be warranted.

Australia↗
PubMed1983

Infections with a Malaysian dog strain of Ancylostoma ceylanicum in outbred, inbred and immunocompromised mice.

The course of infection with a Malaysian dog strain of Ancylostoma ceylanicum was investigated in 15 inbred strains of mice, in outbred and inbred mice immunosuppressed with prednisolone, and in immunodeficient hypothymic mice. Oral, percutaneous and subcutaneous routes of infection, in both sexes of mice, were assessed. In only one instance was a single small adult male worm found. Following oral infection, larvae migrated from the stomach to the large bowel and then a proportion of worms penetrated the perianal skin. This was followed by the appearance of larvae in the lungs. Living 3rd-stage larvae were seen in the anterior small intestine, perianal skin and lungs for the 6 weeks of the study, with peak recoveries being at 12 h, 8 days and 3 weeks, respectively. It is clear that systemic migration of larvae occurs after oral infection, and it is possible that recirculation may occur. Only a small percentage of larvae penetrated the abdominal skin after being administered percutaneously. In subcutaneous infections, a small proportion of larvae moved rapidly from the site of injection and were recovered from the lungs 2 h after infection. Most larvae, however, migrated from the injection site over the ensuing few days. Living 3rd-stage larvae were seen in the lungs and in the small intestine for the 4 weeks of observation. The strain of A. ceylanicum employed does not complete its development in mice. Nevertheless, this model offers significant potential for studying the immune responses, as well as investigating the means by which these parasites evade host defences.

Ancylostoma↗
PubMed1983

A selective broth for Clostridium difficile.

A selective broth for the isolation of Clostridium difficile from stool specimens is described. The broth contains gentamicin, cycloserine and cefoxitin (GCC broth) and gives rapid presumptive evidence of the presence of C. difficile using gas-liquid chromatography. The broth may also be used for the detection of cytotoxin. Final recovery of C. difficile was significantly improved with an increase in isolation rate of 20% in patients in whom fecal cytotoxin could be detected and 125% in patients where fecal cytotoxin could not be detected. Until the pathogenesis of C. difficile-associated diseases is more clearly defined we would stress the importance of isolating the organism, and we advocate the use of a selective broth such as GCC to improve the isolation rate.

Cefoxitin↗
PubMed1982

Humoral and cell-mediated immune responses in murine strongyloidiasis.

The immunological changes occurring after primary and challenge infections with Strongyloides ratti in C57B1/6 mice are described. Serum IgM and IgG antibodies against Strongyloides antigen appeared one week after primary infection. The levels of antibody in both immunoglobulin classes increased markedly after secondary infection and persisted for at least 6 weeks. Immediate hypersensitivity (15 min footpad) reactions were transient after a primary infection, but were marked and persistent after a secondary infection. Arthus (5 h footpad) reactions were mild and very transient after a primary infection, but a persistent anamnestic response was seen after challenge infection. Cell-mediated immune (24 h footpad) reactions were marked 1 week after both primary and secondary infections but were not sustained in either case. Antigen-reactive cells were present in the mesenteric lymph nodes 1 week after primary infection and 1-4 weeks after challenge infection. No antigen-reactive cells were noted in the spleen. Mesenteric lymph node (MLN) cells and spleen cells from infected or uninfected animals were stimulated with phytohaemagglutinin (PHA) or lipopolysaccharide (LPS) but did not differ significantly in their 3H thymidine incorporation. A transient eosinophilia was observed after primary infection and an anamnestic response was noted after challenge infection. The possible roles of these immunological responses to worm rejection and immunopathology are considered.

Animals↗
PubMed1981

Different cell-surface receptor determinants of antigenically similar influenza virus hemagglutinins.

Two influenza virus substrains, A/RI/5-/57 and A/RI/5+/57, with antigenically similar hemagglutinins and neuraminidases but with different properties of elution from erythrocytes, have been examined for the specificity of their interaction with cell surface sialyloligosaccharides. This was accomplished by using erythrocytes treated with Vibrio cholerae neuraminidase to remove sialic acids, and then modified with CMP-NeuAc and three purified sialyltransferases to contain either the NeuAc alpha 2,3Gal, NeuAc alpha 2,6Gal, or NeuAc alpha 2,6GalNAc linkages on cell-surface glycoproteins. Each virus was tested for its ability to adsorb to and hydrolyze sialic acid from the derivatized cells. The hemagglutinins of the A/RI/5-/57 and A/RI/5+/57 viruses were found to have totally different specificities, binding respectively to the NeuAc alpha 2,3Gal and NeuAc alpha 2,6Gal linkages as preferred receptor determinants. In contrast, the neuraminidases of the two viruses exhibited similar specificities, efficiently hydrolyzing only the NeuAc alpha 2,3Gal linkage. The results suggest that the difference in the ability of the A/RI/5-/57 and A/RI/5+/57 viruses to elute from erythrocytes resides in the different receptor specificities of their hemagglutinins. Indeed, it appears that A/RI/5-/57 virus elutes because its receptor determinant, NeuAc alpha 2,3Gal, is rapidly hydrolyzed by the viral neuraminidase, while the A/RI/5+/57 virus fails to elute because its preferred receptor determinant NeuAc alpha 2,6Gal is largely resistant to hydrolysis.

Epitopes↗
PubMed1981

Serodiagnosis of human strongyloidiasis by an enzyme-linked immunosorbent assay.

The sensitivity specificity of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of strongyloidiasis has been investigated. 45 men with long-standing strongyloidiasis were compared with the same number of age- and sex-matched control subjects. The ELISA detected antibody in 84% of patients with parasitologically proven strongyloidiasis. When the technique was compared with an indirect immunofluorescent assay (IFA), a high correlation coefficient was obtained. Specificity was demonstrated by observing a marked fall in optical density of pooled positive serum after prior incubation with Strongyloides ratti soluble antigen but not after incubation with antigens derived from Ascaris suum or Dirofilaria immitis. The test is simple and offers a useful method for the diagnosis of strongyloidiasis. In these patients it was more reliable than a single parasitological examination of faeces or duodenal contents.

Antibody Specificity↗
PubMedDate not supplied

Facial fractures in Gaelic football and hurling.

A one year, retrospective, epidemiological study of all facial fractures, sustained whilst playing the GAA sports of football and hurling, treated in the Cork Regional Hospital was undertaken. The results have been analysed and compared to a similar study performed in this unit in 1975. Of 332 patients treated for facial fractures, 110 (33%) were injured whilst playing sport and 47% of these occurred when playing Gaelic football or hurling (52 injuries in all). Eighty per cent of Gaelic football and hurling patients required operative treatment. All surgery was performed under general anaesthetic. The numbers of hurling fractures have more than halved since 1975-76. This coincides with an increase in the numbers hurling, an increase in the use of protective headgear and vastly improved coaching. This study demonstrates that improved safety can be achieved without diluting sporting enjoyment.

Adolescent↗