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Biomedical subjects

S Stephens

Publications and source records attributed to S Stephens.

89 records · Page 5Linked to original sources
PubMed1978

Stimulation of the development of bacteriostatic activity of guinea-pig milk against Escherichia coli.

The bacteriostatic activity of guinea-pig milk against various strains of Escherichia coli has been examined. Milk collected from sows suckling normal young was usually inactive, but the activity of milk from sows suckling young which had been orally infected with Esch. coli was significantly increased. The increase occurred in 2 phases: the first was found as early as 24 h after infection, suggesting stimulation via the teat canal (diathelic), but lasted only 2-3 days; the second occurred from 10 days post-infection onwards, and lasted until the end of lactation. The occasional bacteriostatic activity of milk from sows with normal young was not correlated with the presence in the faeces of naturally occurring Enterobacteriaceae, including Esch. coli.

Animals↗
PubMed1977

Bacteriostasis of Escherichia coli by milk. II. Effect of bicarbonate and transferrin on the activity of infant feeds.

Fresh human and bovine milk are bacteriostatic in vitro for only some (milk-sensitive) strains of E. coli. The addition of bicarbonate to the test system potentiates the bacteriostasis so that otherwise milk-resistant strains are inhibited. By titration of the bicarbonate in the milk, it is possible to determine the minimum concentration that will activate milk aganinst a milk resistant strain but be ineffective in boiled milk, i.e. it potentiates a heat-labile system in milk and does not merely exert a direct toxic effect. This concentration is lower for human milk than for cow's milk and can be reduced even further by the addition of more iron-binding protein. Lactoferrin and bicarbonate may be present in the gut of the newborn. In an attempt to imitate conditions in the infant gut, we therefore reinvestigated, in vitro and in the presence of added bicarbonate and transferrin, the bacteriostatic activity against E. coli of fresh breast-milk, commercial bottle-milk, and mixtures of these as fed to infants in the study. The results, and information about events in vivo deduced from the ratio of milk-sensitive to milk-resistant strains of E. coli isolated from babies' stool suggest that neonatal intestinal secretions may contribute to the bacteriostatic activity of their feeds so that (1) in fully breastfed babies all strains of E. coli are inhibited to the same extent; there is no selection on the basis of milk sensitivity and equal numbers of strains resistant and sensitive to milk are found in the stools; (2) in fully bottle-fed babies E. coli is not inhibited since the milk is non-bacteriostatic and again there is no selection; (3) in babies fed at the breast but bottle-milk supplemented, only milk-sensitive strains are inhibited; milk-resistant strains are not, and preferentially colonize the large intestines.

Animals↗
PubMed1973

Pertussis antibodies in the sera of children exposed to Bordetella pertussis by vaccination or infection.

Low agglutinin titres to pertussis suspensions were found in 99% of sera from a group comprising healthy adults and non-vaccinated, non-infected infants of 1-6 months of age. These are attributable to agglutinins to heat-stable antigens and/or heat labile agglutinogen 1, and cross-absorption tests must be done on the sera in order to distinguish between the two. Agglutinins to agglutinogens 2 and 3 were found in only about 20% of adult sera. Bactericidal antibody was low in titre or absent in all sera from non-exposed individuals.Raised bactericidal antibody titres and the presence of agglutinins 2 and 3 were attributed to exposure to Bordetella pertussis antigens, either as vaccine or as infection. The variation, amongst both vaccinated and infected children, was very great. A vaccinated child who became ill responded to the infection in much the same way as a non-vaccinated child. We were unable to relate the immunity of the child to the titres either of agglutinins or of the bactericidal antibody.The protective ability of sera from vaccinated or infected children measured in mice against small, lethal brain infections was also unrelated to the state of immunity in the children, but this protective ability was correlated with the complement-mediated bactericidal antibody titres of the sera.The distribution of agglutinins, bactericidal antibody, and anti-haemagglutinin in serum IgG and IgM was different in vaccinated and infected children.

Adolescent↗
PubMedDate not supplied

Levels of tumour necrosis factor and soluble TNF receptors during malaria fever episodes in the community.

The pyrogenic cytokine, tumour necrosis factor (TNF), is a mediator of malaria fever. Since high plasma levels of TNF are sometimes found in afebrile individuals with Plasmodium falciparum parasitaemia, it has been suggested that soluble forms of TNF receptors (sTNF-R55 and sTNF-R75) in the plasma may act to inhibit the pyrogenic effect of TNF. We have investigated plasma levels of TNF, sTNF-R55 and sTNF-R75 in relation to episodes of malaria fever detected in a cross-sectional study of 313 rural Gambian children during the malaria transmission season. Levels of TNF were significantly higher in the 20 children who had parasitaemia associated with fever than in 120 children who were afebrile despite malaria infection and 173 who had no detectable parasitaemia. In contrast, soluble TNF receptor levels did not differ between these clinical groups and, in a logistic regression model which included level of parasitaemia, we found TNF but not soluble TNF receptor levels to be associated with the presence of fever. These data support the role of TNF in malaria fever but suggest that soluble TNF receptors are not a major factor in modulating the fever.

Child, Preschool↗
PubMedDate not supplied

Health care professionals referred for treatment of alcohol and drug problems.

This study reports on 62 health care professionals referred to a specialist drug and alcohol treatment service. Most patients used more than one type of substance. Health problems were common, but were seldom reasons for referral. Self-referral was infrequent. Referral was often subsequent to intoxication at work or persistent absenteeism. Just over half of admissions completed treatment. Multiple drug use was a poor prognostic indicator with fewer multiple drug users engaging with, or completing, treatment.

Adult↗
PubMedDate not supplied

MR imaging using a rampable system.

A series of cranial images obtained at three magnetic field strengths in a volunteer on a fast ramp magnetic resonance system is presented. This study was undertaken in the space of 5 h.

Brain↗
PubMedDate not supplied

Use of learning contracts in a RN-to-BSN leadership course.

Educating RN-to-BSN students can be challenging and rewarding. The diversity of these students can make designing courses quite difficult. In addition, the RN with experience in nursing practice may resent being put in the traditional role of student. Nominal group process and use of learning contracts in a leadership course in one RN completion program are described as two means of meeting the unique learning preferences of working, adult learners. Houle (1984) identified the learning contract as one means of assisting the adult learner seeking continuing professional education. Accordingly, examples of use of these two strategies in continuing nursing education and staff development are described.

Attitude of Health Personnel↗
PubMedDate not supplied

Therapy with attitude.

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Community Mental Health Services↗
PubMedDate not supplied

Fast forward.

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Community Mental Health Services↗