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Biomedical subjects

P J Matthews

Publications and source records attributed to P J Matthews.

At least 19 recordsLinked to original sources
PubMed2005

Functional abdominal pain.

Functional abdominal pain or functional abdominal pain syndrome (FAPS) is an uncommon functional gut disorder characterised by chronic or recurrent abdominal pain attributed to the gut but poorly related to gut function. It is associated with abnormal illness behaviour and patients show psychological morbidity that is often minimised or denied in an attempt to discover an organic cause for symptoms. Thus the conventional biomedical approach to the management of such patients is unhelpful and a person's symptom experience is more usefully investigated using a biopsychosocial evaluation, which necessarily entails a multidisciplinary system of healthcare provision. Currently the pathophysiology of the disorder is poorly understood but is most likely to involve a dysfunction of central pain mechanisms either in terms of attentional bias, for example, hypervigilance or a failure of central pain modulation/inhibition. Although modern neurophysiological investigation of patients is promising and may provide important insights into the pathophysiology of FAPS, current clinical management relies on an effective physician-patient relationship in which limits on clinical investigation are set and achievable treatment goals tailored to the patient's needs are pursued.

Abdominal Pain↗
PubMed2000

A ketogenic diet has different effects upon seizures induced by maximal electroshock and by pentylenetetrazole infusion.

The purpose of these experiments was to determine whether a ketogenic diet previously shown to elevate seizure threshold also reduced seizure severity. Seizure threshold was tested by intravenous infusion of pentylenetetrazole (PTZ) whereas seizure severity was determined from measuring the hindlimb extension to flexion (E/F) ratio after seizures were evoked by maximal electroshock stimulation (MES). Surprisingly, seizures evoked by MES were more severe in animals fed a calorie-restricted ketogenic diet. Controls fed an isocaloric, calorie-restricted normal diet also exhibited more severe seizures than did animals fed the same diet ad libitum. When seizure threshold was evaluated in the same animals, those animals fed a calorie-restricted ketogenic diet exhibited a significant increase in seizure resistance compared to animals fed a ketogenic diet ad libitum, a calorie-restricted normal diet or a normal diet ad libitum. These findings suggest that both the amount and type of food affect seizures in rats and show that diet-related seizure protection depends upon the method by which seizures are provoked.

3-Hydroxybutyric Acid↗
PubMed1994

A comparison of postoperative analgesia following spinal or epidural anaesthesia for caesarean section.

Postoperative analgesia, using a patient-controlled analgesia system, was studied in 32 women after elective Caesarean section performed under either spinal or epidural anaesthesia. Patients who had spinal anaesthesia had significantly higher pain scores and morphine consumption during the first 4 h postoperatively than patients who had epidural anaesthesia. This situation was reversed between 4 to 8 h postoperatively with patients who had had epidurals having significantly higher pain scores despite higher morphine consumption. After 8 h there was little difference in pain scores or morphine use between the two groups. Total morphine consumption in the first 24 h postoperatively was not significantly different between the two groups.

Analgesia, Patient-Controlled↗
PubMed1991

Methods for detection and frequency of contamination of fetal calf serum with bovine viral diarrhea virus and antibodies against bovine viral diarrhea virus.

Methods used by the National Animal Disease Center to test fetal calf serum for contamination with bovine viral diarrhea virus (BVDV) and antibodies against BVDV are described. Using those methods, virus was isolated from 332 of 1,608 (20.6%) lots of raw fetal calf serum obtained specifically for the Center and 93 of 190 (49%) lots of commercially available fetal calf serum. Virus neutralization and immunoperoxidase staining tests were used to detect antibodies against BVDV in 224 of the 1,608 (13.9%) lots of raw fetal calf serum. Both BVDV and antibodies against BVDV were detected in 50 lots of raw serum. The molecular specificity of antibodies against BVDV was determined by radioimmunoprecipitation. Lots of fetal calf serum that contained BVDV-specific antibodies that did not neutralize virus were identified.

Animals↗
PubMed1990

Antibodies to bovine parvovirus acquired by neonatal pigs through ingestion of virus and antibody in the diet.

The ability of pigs to respond immunologically to ingestion of bovine parvovirus (BPV) was tested by feeding 4 cesarean-derived, colostrum-deprived (CDCD) pigs a live virus-contaminated, liquid diet for the first 4 weeks of life. Virus-neutralizing (VN) antibodies were detected in the serum of 2 of the 4 pigs when they were 4 weeks old. Antibody titer remained at about the same level for several weeks, then decreased during the remainder of the 29-week interval of testing. The relative reactivity of these sera based on results of indirect immunofluorescence paralleled the corresponding VN titer. Neither of the other 2 pigs exposed to BPV had any appreciable immune response. The potential for passive acquisition of antibody from the diet was tested by feeding 4 other CDCD pigs bovine colostrum containing antibodies to BPV and bovine viral diarrhea virus (BVDV) for the first 2 days of life. All had serum VN antibodies for both viruses when they were tested at 2 days of age. The decay rate of the heterologous, passively acquired antibody was approximately linear; however, antibody half-life was relatively short, about 3.5 days, and titers were no longer detectable when pigs were 4 weeks (BPV) and 6 weeks (BVDV) old. An additional 4 CDCD pigs fed a liquid diet without virus or antibody remained free of any appreciable serum reactivity for either BPV or BVDV. Results supported the hypothesis that antibodies for BPV previously detected in the serum of pigs and people may reflect ingestion of virus-contaminated bovine milk or milk products.

Animals↗
PubMed1989

Aminergic and peptidergic modulation of motor function at an identified neuromuscular junction in Helisoma.

Electrophysiological studies suggest that motoneurone B19 in the buccal ganglia of Helisoma makes monosynaptic, cholinergic connections with the supralateral radular tensor (SLT) muscle of the buccal mass. Serotonin (5-HT) and small cardioactive peptide B (SCPB) were found to have peripheral modulatory effects on this motor pathway that are consistent with their previously described central facilitatory effects. Both neurotransmitters, when applied exogenously (10(-6) mol l-1) to isolated buccal ganglion-buccal muscle preparations, potentiated the magnitude of motoneurone B19-evoked muscle contractions (6.3 and 2.7 times, respectively) without affecting excitatory junctional potential (EJP) amplitudes. When applied to single dissociated SLT muscle fibres in cell culture, these modulators had similar effects on acetylcholine (ACh)-evoked muscle fibre shortening, demonstrating that these neuromodulators exert direct actions on the muscle cells. The cardioactive peptide FMRFamide (10(-6) mol l-1), although slightly potentiating muscle contractions in reduced neuromuscular preparations, significantly decreased both ACh-evoked muscle fibre shortening and depolarizing potentials in cultured SLT muscle cells. The differential effects of FMRFamide may, in part, be due to the elimination of interactive effects between multiple neurotransmitters that might exist in semi-intact preparations and in vivo. These results demonstrate that 5-HT, SCPB and FMRFamide in Helisoma can directly modulate the peripheral muscle targets of buccal motoneurones involved in the generation of cyclical feeding behaviour.

Acetylcholine↗
PubMed1989

The causal prophylactic activity of the novel hydroxynaphthoquinone 566C80 against Plasmodium berghei infections in rats.

The influence of the novel hydroxynaphthoquinone 566C80 on exoerythrocytic development of Plasmodium berghei was examined in Brown Norway rats. The procedure employed was designed to identify residual activity of the drug against tissue merozoites emerging into the bloodstream and to distinguish this from any observed causal prophylactic activity against the liver stages. Single oral doses of 10 and 1 mg/kg of 566C80 administered 3 hours after sporozoite-inoculation were effective in preventing the appearance of a patent parasitaemia, while a dose of 0.1 mg/kg significantly reduced the severity of the ensuing blood infection. There was a pronounced residual effect of 566C80 against the blood forms at a dose of 10 mg/kg, a slight residual effect at a dose of 1 mg/kg, but no apparent residual effect at 0.1 mg/kg. At the time when EE merozoites would normally emerge into the bloodstream, an aliquot of blood was sub-inoculated into mice from sporozoite-infected, 566C80-treated rats. This procedure confirmed that 566C80 is active against the exoerythrocytic stages of Plasmodium berghei.

Animals↗
PubMed1986

Effects of microbial and host variables on the interaction of rotavirus and Escherichia coli infections in gnotobiotic calves.

Naturally occurring mixed infections with Escherichia coli and rotavirus have been associated with fatal diarrhea of calves about 1 week old. Experiments were designed to reproduce this syndrome in gnotobiotic calves. Clinical, microbiological, and pathologic data were used to assess severity of disease and mechanisms of the interaction between the 2 infections. An initial study involved 5- to 8-day-old gnotobiotic calves inoculated with a strain of enterotoxigenic E coli (ETEC) and a strain of rotavirus. Calves were observed for 2 days after they were inoculated; fatal diarrhea was not produced. In later studies, variables were tested to identify those that might contribute to fatal diarrhea. Variables which did not result in fatal or severe diarrhea or which did not cause disease that was more severe in dually inoculated calves than that in monoinoculated calves were increasing feed to 2 times base line, increasing dose of ETEC to 10 times base line, inoculating calves when they were 2 days old, using a strain of E coli that causes colisepticemia, and using a different strain of rotavirus. When the observation period was extended from 2 days to 6 days after calves were inoculated, severe, watery, fatal diarrhea occurred in 6 of 12 calves by 32 to 72 hours after dual inoculation was given. Fatal diarrhea was associated with intensive colonization by the ETEC in the caudal half of the small intestine. Microscopic lesions were similar between dually inoculated and rotavirus-monoinoculated calves, except there was more severe atrophy of ileal villi of dually inoculated calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Susceptibility of colostrum-deprived swine of various ages to streptococcic lymphadenitis.

The effect of age on susceptibility of young pigs to streptococcic lymphadenitis was investigated. Twenty-nine cesarean-derived, colostrum-deprived pigs were allotted to 7 groups exposed to type IV group E Streptococcus (GES) at 5, 14, 28, 35, 56, 70, and 84 days of age. Four cesarean-derived, colostrum-deprived pigs were maintained as nonexposed controls. Six naturally farrowed, susceptible controls were exposed to GES at 63 to 84 days of age. All exposed pigs were killed and necropsied 28 days after exposure. Lesions of streptococcic lymphadenitis were not observed in pigs exposed at 5 or 14 days of age, except for 1 microabscess in a mandibular lymph node in a pig exposed at 14 days, but GES was recovered from 11% of lymph nodes examined from pigs of those age groups. Lesions and GES-positive lymph nodes were frequent in cesarean-derived, colostrum-deprived pigs exposed at 28 days and older and in susceptible controls. Serologic response to exposure, as determined by microtitration agglutination test and bactericidal test, was observed only in pigs exposed at 14 days and older. The absence of abscess development in pigs exposed at 5 or 14 days of age was not caused by antibody or failure of infecting organisms to reach the target organs.

Animals↗
PubMed1981

Production of lesions in gnotobiotic mice by inoculation with Treponema hyodysenteriae.

Treponema hyodysenteriae was established in the ceca of gnotobiotic mice in the absence of other organisms. Superficial mucosal lesions characteristic of swine dysentery were present in the ceca of mice inoculated with T. hyodysenteriae in combination with viable Bacteroides vulgatus. Deep crypt necrosis was detected in the ceca of mice inoculated with T. hyodysenteriae alone.

Animals↗
PubMed1979

Pathogenic synergism between Treponema hyodysenteriae and other selected anaerobes in gnotobiotic pigs.

Gnotobiotic pigs were orally exposed to various anaerobes at 6 to 9 days of age and similarly inoculated with Treponema hyodysenteriae B204 3 to 6 days later. Watery diarrhea and fecal excretion of large quantities of mucus and some fibrin clots were observed 4 to 20 days after inoculation with B204 if other anaerobes were present. Colonic lesions characteristic of swine dysentery were observed when B204 was present with Fusobacterium necrophorum, three strains of Bacteroides vulgatus, a Clostridium species, and Listeria denitrificans individually and when some of these microbes were present in various combinations, but not when B204 was present alone. These results are consistent with the conclusion that T. hyodysenteriae is the primary pathogen in the etiology of swine dysentery and that the presence of one or more other anaerobes is a prerequisite for expression of pathogenicity of T. hyodysenteriae. This prerequisite can be met by a variety of anaerobes.

Anaerobiosis↗
PubMed1978

Swine dysentery: studies of gnotobiotic pigs inoculated with Treponema hyodysenteriae, Bacteroides vulgatus, and Fusobacterium necrophorum.

Transmission experiments were carried out in gnotobiotic pigs to determine whether lesions typical of swine dysentery could be produced by oral inoculation of Treponema hyodysenteriae in combination with Bacteroides vulgatus or Fusobacterium necrophorum, or both. Each of the organisms had been isolated from swine with early lesions of the disease. Lesions were not found in 6 pigs inoculated with T hyodysenteriae alone, in 4 pigs given F necrophorum and T hyodysenteriae, or in 4 pigs given B vulgatus and F necrophorum. Lesions typical of swine dysentery developed in 8 pigs given B vulgatus, F necrophorum, and T hyodysenteriae as well as in 3 of 4 pigs given B vulgatus and T hyodysenteriae. In both of these groups, the inoculated bacteria were recovered from the colon, and T hyodysenteriae was demonstrated in the colonic crypts, epithelium, and lamina propria. The pathogenicity of the T hyodysenteriae was shown by the development of characteristic signs and lesions of swine dysentery in 12 of 14 naturally farrowed pigs inoculated with T hyodysenteriae alone.

Animals↗