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Biomedical subjects

R J Gilbert

Publications and source records attributed to R J Gilbert.

At least 91 records · Page 5Linked to original sources
PubMed1987

Effect of cisapride, a new prokinetic agent, on esophageal motor function.

In this study, we assessed by a double-blinded, cross-over design the effect of intravenous and oral cisapride on esophageal motor activity during the late fed state in normal subjects. For the intravenous study, subjects were given placebo or 10 mg cisapride randomly, while in the oral study, they randomly received placebo or cisapride at 5, 10, or 20 mg. Cisapride given intravenously or orally caused a significant increase in resting LES pressure. The increase in LES pressure after oral administration was significant only after the 20 mg dose. Esophageal-body peristaltic amplitude, determined for all smooth-muscle sites, showed a modest but significant increase of approximately 10 mm Hg after intravenous cisapride, whereas no significant increase occurred after oral cisapride. Propagation time of peristalsis was unaffected by intravenous or oral cisapride. Side effects of treatment were minimal and at no time necessitated cessation of the study. We conclude that in healthy subjects during the late fed period, (1) cisapride at 10 mg intravenously or 20 mg orally increased resting LES pressure and (2) at 10 mg intravenously, but at no oral dose, cisapride increased peristaltic amplitude without affecting propagation time. The potentiating effect of cisapride on LES pressure suggests that cisapride could have an ancillary role in the therapy of gastroesophageal reflux disease.

Adult↗
PubMed1987

Subtypes of muscarinic receptors in vagal inhibitory pathway to the lower esophageal sphincter of the opossum.

We assessed the characteristics of muscarinic neural transmission in the vagal inhibitory pathway to the lower esophageal sphincter (LES) of anesthetized opossums. LES relaxation was induced by electrical stimulation of the cervical vagus. Measurements were made of LES relaxation before and after intravenous administration of nicotinic (hexamethonium), serotonergic (5-Meo-DMT), nonselective muscarinic (atropine), and selective muscarinic (pirenzepine-M1 and 4-DAMP-M2) antagonists. The latency of LES relaxation was increased substantially by pirenzepine and atropine, increased slightly by hexamethonium, but was not affected by 4-DAMP or 5-Meo-DMT. Given as concurrent intravenous infusions, hexamethonium, 5-Meo-DMT and 4-DAMP added to pirenzepine or atropine did not significantly increase LES relaxation latency above that caused by pirenzepine or atropine alone. None of the antagonists alone had a significant effect on percent LES relaxation. The combination of pirenzepine or 4-DAMP with hexamethonium and 5-Meo-DMT did not affect percent LES relaxation. The combination of atropine with hexamethonium and 5-Meo-DMT reduced LES relaxation to 18%. The combination of pirenzepine and 4-DAMP with hexamethonium and 5-Meo-DMT, however, had no effect on percent LES relaxation. We conclude that muscarinic participation in vagally induced LES relaxation exhibits two functional receptor subtypes: (1) M1 receptors that determine LES relaxation latency and are antagonized by pirenzepine or atropine, and (2) non-M1, non-M2 receptors (Mx receptors) that contribute to the magnitude of LES relaxation and are antagonized by atropine, but not by pirenzepine or 4-DAMP.

Animals↗
PubMed1987

Assessment of an enzyme immunoassay for the detection of salmonellas in foods and animal feeding stuffs.

The Salmonella Bio-EnzaBead Screening Kit, in its modified form with both the MOPC 467 and the 6H4 antibodies, was used for the detection of salmonellas in naturally contaminated foods and animal feeding stuffs in parallel with a traditional cultural procedure. Initial results showed an 82% agreement between the enzyme immunoassay (EIA) and cultural methods when using the criterion recommended by the manufacturer as a cut-off for all types of foods. By adjusting the cut-off for each type of food, the number of EIA positive, culture negative samples was reduced although the number of EIA negative, culture positive samples increased. The EIA may be more sensitive than the cultural methods as in many cases the EIA positive, culture negative results could be real positives which were not detected by the cultural methods. The screening kit provides a simple and convenient method for the detection of salmonella in foods and feeds and a presumptive positive result can be reported within 48 h. The advantages and disadvantages of the method are discussed.

Animal Feed↗
PubMed1987

Scombrotoxic fish poisoning in Britain: features of over 250 suspected incidents from 1976 to 1986.

Between 1976 and 1986, 258 incidents of suspected scombrotoxic fish poisoning were reported in Britain. Histamine analysis was carried out on 240 fish samples from these incidents, and 101 were found to contain greater than 5 mg histamine/100 g fish. The symptoms most consistently reported were rash, diarrhoea, flushing and headache. In recent years there has been a decrease in the number of confirmed scombrotoxic outbreaks and a trend towards more sporadic incidents. Of fish samples with greater than 20 mg histamine/100 g, 94% were from incidents in which scombrotoxic symptoms were characteristic, but where fish had 5-20 mg/100 g only 38% of incidents were clinically distinctive. Guidelines are presented based on the interpretation of quantitative histamine analysis of fish samples from scombrotoxic poisoning incidents.

Animals↗
PubMed1987

The oral retention and antiplaque efficacy of triclosan in human volunteers.

An antiplaque toothpaste containing 0.2% (w/w) triclosan significantly inhibited overnight plaque growth in 12 human volunteers. After use of a 1 g quantity of the toothpaste containing 0.2% (w/w) [3H]-triclosan, 36.3 +/- 1.4% of the triclosan was retained. The mean concentration (+/- s.d.) achieved in saliva 5 min after toothpaste use was 8.16 +/- 2.50 micrograms g-1. The saliva decay curve for triclosan was consistent with a two phase model with t1/2 values of 0.45 h and 2.42 h, respectively. Triclosan was present in bacterial plaque for at least 8 h after dosage and in the oral mucosa for at least 3 h.

Adult↗
PubMed1987

The oral clearance of zinc and triclosan after delivery from a dentifrice.

Oral delivery and retention of zinc and triclosan were measured in man after use of an anti-plaque dentifrice containing these antibacterial agents. Triclosan (25% of the dose) and zinc (24%) were retained in the mouth immediately after toothbrushing and a single mouthrinse. Salivary concentrations fell from 7.5 micrograms g-1 (triclosan) and 7.0 micrograms g-1 (zinc) after 5 min to 0.5 micrograms g-1 (triclosan) and 1.2 micrograms g-1 (zinc), 2 h after brushing.

Adult↗
PubMed1987

Effect of morphine on electrophysiological properties of circular and longitudinal muscles.

We have measured the effects of morphine on the intracellular electrophysiological properties of smooth muscle cells from the circular and longitudinal muscle layers of the canine jejunum. Morphine hyperpolarized the circular muscle membrane by approximately 12 mV and increased the electrical control activity (ECA) amplitude and dV/dt. Morphine had no significant effect on the electrical properties of the longitudinal muscle cells. The morphine-induced hyperpolarization of the circular muscle membrane was blocked by tetrodotoxin (TTX) and naloxone, but not by atropine and hexamethonium, propranolol, or phentolamine. Morphine significantly increased the slope of the resting membrane potential vs. the log of the potassium concentration in bathing medium from 38 to 50 mV/decade. The sodium permeability to potassium permeability ratio, calculated from the Goldman constant field equation, was reduced by morphine from 0.13 to 0.07 at mM of K+. The above results suggest that when measured by intracellular techniques, morphine hyperpolarizes the circular muscle membrane by release of a nonadrenergic, noncholinergic neurotransmitter. The mechanism of this hyperpolarization is consistent with an increase in potassium conductance.

Animals↗
PubMed1987

Treatment of the congenital vertical talus: a retrospective review of 36 feet with long-term follow-up.

To ascertain whether one type of treatment of the congenital vertical talus was superior to others, we conducted a retrospective analysis of 36 congenital vertical tali in 21 patients whose average follow-up of 14 years was considered to be unusually lengthy. Ten patients (48%) had an underlying primary diagnosis, and 13 patients (62%) had at least one other secondary congenital abnormality. None of the surgical techniques produced significantly better results than any other one according to criteria involving shoewear, range of motion, and degree of pain. Subtalar and talotibial motion were frequently restricted, with or without prior arthrodesis. Pain generally was not an immediate or long-term problem. To maintain maximal foot mobility, we recommend a one-stage soft tissue correction alone in the child under 3 years of age. In older, untreated children or those in whom conservative treatments have failed, a subtalar or triple arthrodesis may be necessary.

Adolescent↗
PubMed1986

International outbreak of staphylococcal food poisoning caused by contaminated lasagne.

An outbreak of staphylococcal food poisoning in Europe caused by contaminated lasagne was detected and monitored by both national and international surveillance systems. The common source was a pasta-producing factory in Italy and high levels of Staphylococcus aureus were detected in packets of dried lasagne distributed in Luxembourg, the UK, France and Italy. Forty-seven cases were reported in the UK. Outbreaks of staphylococcal food poisoning attributed to mishandling during the food processing stage are uncommon and pasta as the food vehicle is rare. Prompt recognition of the outbreak and rapid identification of the food vehicle enabled most of the consignment to be withdrawn from the market.

Europe↗
PubMed1986

Effect of selective muscarinic antagonists on peristaltic contractions in opossum smooth muscle.

In this study we examined the role of M1- and M2-muscarinic receptors in the mediation of circular smooth muscle esophageal contractions elicited by pharmacological cholinergic stimulation and during peristalsis in anesthetized opossums. Esophageal-body contractions were induced by bethanechol administration, whereas peristalsis was elicited by pharyngeal stroking or cervical vagal stimulation. Contractions were measured by a low-compliance manometric recording system. The incidence and amplitude of bethanechol-induced contractions were antagonized by 4-diphenylacetoxy-n-methylpiperidine (4-DAMP) and atropine but not pirenzepine. 4-DAMP and atropine caused an increased velocity, decreased amplitude, and preferential reduction of the incidence of primary peristaltic contractions in the proximal smooth muscle esophagus. During long-train vagal stimulation, intra-stimulus A-waves had a velocity similar to primary peristalsis, whereas poststimulus B-waves showed a velocity considerably faster than primary peristalsis. Short-train vagal stimulation produced a contraction sequence, termed an "S-wave," that had a velocity similar to that of the A-wave. At low doses 4-DAMP increased the velocity and decreased the amplitude of A-wave and S-wave contractions, and at high doses 4-DAMP abolished both the A-wave and S-wave contractions. B-wave contractions were minimally affected by 4-DAMP. Pirenzepine had no effect on contractions induced by swallows or vagal stimulation. We conclude that M2-muscarinic receptors mediate esophageal contractions in the circular smooth muscle during primary peristalsis and during A-waves and S-waves induced by vagal stimulation, and M1-receptors do not have any important role in the excitatory neural pathway to the esophagus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The first complete enumeration of Papua New Guinea--the 1980 population census.

"The 1980 Population Census of Papua New Guinea was the first complete enumeration of the population of the country. It was also the first census to be designed and processed within the country. This paper gives the background to the census and outlines the development and implementation of the project, concentrating on the problems encountered and the procedures developed to overcome them in this (in many ways) unique environment. The census project was a thorough exercise and recommendations are also given for the future."

Censuses↗
PubMed1985

Dissemination of Bacillus cereus in a maternity unit.

During a period of 4 months, 54 of 1059 (5%) specimens received for bacterial culture from neonates in a maternity unit yielded Bacillus cereus. Of the strains isolated, 48 originated from 259 umbilical cord swabs examined. Furthermore, 88% of the isolates belonged to a single, previously undescribed serotype. Strains of the same serotype were also found to be widely distributed in the environment throughout the maternity unit. The primary source of the organism, however, could not be established.

Bacillus cereus↗
PubMed1985

The use of a sandwich ELISA for the detection of staphylococcal enterotoxin A in foods from outbreaks of food poisoning.

Foods from outbreaks of food poisoning were examined for the presence of staphylococcal enterotoxin A (SEA) by a sandwich ELISA using microtitre trays as the solid phase and SEA antibodies raised in sheep. The presence of SEA was confirmed by neutralization tests. The toxin was detected in 12 of 15 foods from separate outbreaks of staphylococcal food poisoning; all 15 foods contained a strain of Staphylococcus aureus which produced SEA. For most foods a simple extraction procedure without a concentration step was sufficient to detect the toxin. The method was semi-quantitative and recoveries of SEA added to control foods varied from 30 to 80%. The foods from outbreaks contained between 1 and 10 micrograms of SEA/100 g. SEA was not found in foods from 21 outbreaks in which an SEA-producing strain of Staph. aureus was not isolated.

Disease Outbreaks↗
PubMed1985

Faecal carriage of Clostridium perfringens.

The numbers and serotypes of Clostridium perfringens present in the faeces of three groups of hospital patients and young healthy laboratory workers were examined in studies lasting between 10 and 13 weeks. In one hospital some long-stay geriatric patients carried relatively high numbers of C. perfringens (greater than 10(7)/g) most of the time and it was not unusual in any one week for the majority of these patients to carry the same serotype(s). However, the numbers of C. perfringens in the faeces of young long-stay patients in the same hospital were in the range of 10(3)-10(4)/g and carriage of common serotypes was not observed. These results were similar to the findings with the young laboratory workers. This investigation indicates that two of the laboratory criteria often used in the investigation of C. perfringens food poisoning, i.e. faecal counts of greater than or equal to 10(5) C. perfringens/g and patients carrying the same serological type need to be interpreted with caution with suspected outbreaks involving some groups of geriatric long-stay hospital patients.

Clostridium perfringens↗
PubMed1985

Development and application of an enzyme linked immunosorbent assay for Clostridium perfringens type A enterotoxin.

An enzyme linked immunosorbent assay (ELISA) has been developed to quantitate faecal Clostridium perfringens enterotoxin in the investigation of C perfringens food poisoning. The sandwich ELISA could be carried out in 24 h and was sensitive enough to detect as little as 5 ng/g of enterotoxin in faeces. Specificity of the assay was shown by comparing results with those obtained from other standard toxin assays, such as double gel diffusion and counterimmunoelectrophoresis, and by the assay of faecal material from control groups. By means of the ELISA method, 515 faecal samples from 50 separate outbreaks of C perfringens food poisoning were examined, together with 21 food samples from 12 of the outbreaks. A clear distinction was noted between faecal samples collected on the first two days of an outbreak, where 77% were enterotoxin positive, and those specimens collected later than the second day, when only 33% had detectable enterotoxin. The ELISA is recommended as a valuable tool in the investigation of C perfringens foodborne illness.

Clostridium perfringens↗