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Biomedical subjects

E S Anderson

Publications and source records attributed to E S Anderson.

At least 19 recordsLinked to original sources

Family/media approach to HIV prevention: results with a home-based, parent-teen video program.

We describe the first study with a home-based HIV prevention video program for parents and young teenagers. The objectives of the program are to inform parents and teenagers about the causes and prevention of HIV infection and other sexually transmitted diseases, to increase family problem-solving skills, and to increase teen problem-solving and assertiveness skills. The objectives pertain to the goals of increasing skills needed to help teenagers avoid or manage high-risk behaviors and situations. Forty-five families with at least one 12- to 14-year-old were randomly assigned to either experimental (receive video program) or control (no video) conditions in a pretest-posttest design. After 6 months (Follow-Up 1), the experimental and control families were reassessed. The control families next received the video program, and the control families were assessed again (Follow-Up 2). The results indicate increases in parent and teen knowledge and skills only with video viewing. Approaches to improving the video program, particularly with teenagers, are discussed.

Acquired Immunodeficiency Syndrome

Sleeping position and rectal temperature.

The effects of sleeping position upon body temperature were assessed by continuous monitoring of rectal temperature in 137 babies sleeping at home under conditions chosen by their parents. There were three groups of subjects: (1) normal babies aged 12-22 weeks whose temperature rhythms were developed, (2) normal babies aged 6-12 weeks who were developing their night time temperature rhythms, and (3) babies the night after diphtheria, pertussis, and tetanus immunisation, whose temperature rhythms were disturbed. Sleeping in the prone position was not associated with higher rectal temperatures at any time of night in young babies, nor did it exaggerate the disturbance of rectal temperature rhythm after immunisation. In older normal babies the prone position did not disturb rectal temperature in the first part of the night, though prone sleepers warmed a little faster prior to walking, especially in warm conditions. Prone sleepers were, however, born earlier in gestation and tended to be of lower birth weight. Normal babies can therefore thermoregulate effectively whatever their sleeping posture, even in warm conditions, though the prone position may make it slightly more difficult to lose heat. It is difficult to see how the prone position, even interacting with warm conditions, could induce lethal hyperthermia in otherwise normal babies. Perhaps the prone position is associated with other risk factors for sudden infant death syndrome.

Bedding and Linens

Extending the concept of social validity: behavior analysis for disease prevention and health promotion.

A broader definition of social validity is proposed wherein a socially valid behavior-change intervention is directed to a problem of verifiable importance, the intervention is valued and used appropriately by designated target groups, and the intervention as used has sufficient behavioral impact to substantially reduce the probability of the problem's occurrence in target populations. The verifiable importance of a problem is based on epidemiological data, and the value and appropriate use of an intervention are enhanced through the use of conceptual frameworks for social marketing and behavior change and considerable formative and pilot research. Behavioral impact is assessed through efficacy and effectiveness studies. Thus, the social validity of a behavior-change intervention is established through a number of interactive, a priori steps. This approach to defining social validity is related to critical analysis and intervention issues including individual and population perspectives and "top-down" and "bottom-up" approaches to intervention design. This broader definition of social validity is illustrated by a project to reduce the risk of HIV infection among adolescents. Although the various steps involved in creating socially valid interventions can be complicated, time-consuming, and expensive, following all the steps can result in interventions capable of improving a nation's health.

Adolescent

Neuroleptic malignant syndrome associated with clozapine use.

Clozapine, an atypical antipsychotic drug, is indicated for severely ill schizophrenic patients refractory to treatment with conventional neuroleptics. One advertised advantage of clozapine is the absence of associated neuroleptic malignant syndrome (NMS). On the basis of a clinical case, the authors question this claim. They are concerned that this potentially fatal condition may be misdiagnosed if physicians are not aware of possible NMS associated with the use of clozapine.

Adult

Use of thermographic imaging to study babies sleeping at home.

Two 3 month old infants sleeping under different thermal conditions were found to maintain similar deep body temperatures. Thermographic imaging suggested that though the uncovered head is the main source of heat transfer, other parts of the body such as the hands may be used when necessary.

Body Temperature

Factors influencing the body temperature of 3-4 month old infants at home during the day.

Continuous recordings of rectal temperature were made from 40 normal infants, aged 3-4 months, at home during two days of normal activities. We found that the rectal temperature of a normal, healthy baby may vary from 36.0 degrees C at night to 37.8 degrees C during active periods of the day. During daytime sleep rectal temperature fell, but to a lesser extent, and for less time than during night time sleeps. Feeds raised the temperature unless the baby slept, when they reduced the rate of fall of temperature. Bottle feeds affected temperature more quickly than breast feeds. The changes in temperature during sleep and after feeds were independent of the room temperature or thermal insulation of clothing and wrapping.

Body Temperature

The value of plasmid studies in the epidemiology of infections due to drug-resistant Salmonella wien.

Since 1969 strains of Salmonella wien that are resistant to multiple antibacterial drugs have caused widespread epidemics of enteritis in Europe and North Africa. Of 113 British strains examined between January 1970 and January 1977, 67 were multi-resistant. These strains and 22 strains from six other countries were examined to determine their plasmid content. Two plasmids were found in the vast majority of strains: an FIme factor, conferring resistance to ampicillin, chloramphenicol, kanamycin, streptomycin, spectinomycin, sulfonamides, and tetracyclines (ACKSSpSuT), and a nonautotransferring plasmid of resistance type ASSu. The FIme plasmids have dual incompatibility: they are incompatible with group FI factors and with the MP10 plasmid of Salmonella typhimurium, which belongs to a separate group. Other plasmids found in S. wien included principally a ColIa factor and an autotransferring plasmid that codes for ampicillin resistance and belongs to compatibility group I2. The similarity in plasmid content of strains isolated in widely separated areas suggests that they have a clonal origin.

Ampicillin

Application of agarose gel electrophoresis to the characterization of plasmid DNA in drug-resistant enterobacteria.

A simple gel electrophoresis method has been described for the detection of plasmid DNA in bacteria (Meyers et al., 1976). We investigated further the problems encountered in using this method for the analysis of plasmids in wild enterobacterial strains. The migration of open circular and linear plasmid DNA was examined, since these forms sometimes caused difficulty in the interpretation of the plasmid content of uncharacterized strains. Electrophoresis at different agarose concentrations was employed to resolve clearly plasmid DNA from the chromosomal DNA fragments in the crude preparations. Dissociation of some plasmids occurs in Salmonella typhimurium, and this was detected by electrophoresis. The technique was applied to the study of drug-resistant strains of S. typhimurium phage type 208 from several Middle Eastern countries. The cultures carry a drug resistance plasmid of the FIme compatibility group, and at least two other plasmids which were detected and identified by gel electrophoresis. The studies supported and extended the genetic findings and provided information on the distribution of particular plasmids.

Chromosomes, Bacterial

Correlation of phaga type, biotype and source in strains of Salmonella typhimurium.

A series of 2092 cultures of Salmonella typhimurium isolated from human, animal and other sources in 57 countries were differentiated into 204 phage types and 19 primary and 147 full biotypes. Different biotypes belonged to the same phage type and different phage types to the same biotype, so the combination of typing methods differentiated strains more finely than either method alone: 574 different ;phage type/biotypes' were distinguished in 1937 cultures belonging to the 204 recognized phage types.The combination of biotyping with phage-typing was valuable in studying the phylogeny and spread of epidemic strains by distinguishing clones of different biotype within the same phage type and by confirming the relationship between cultures isolated from widely dispersed clones and that between cultures isolated before and after a clone had undergone variation in phage type, biotype, colicin type or antibiotic-sensitivity pattern.A widespread outbreak of infection with S. typhimurium phage type 141 in Scotland comprised independent dissemination of three clones of different biotypes, 1f, 9f and 31bd. During its epidemic spread in cattle in Britain between 1962 and 1969, another strain underwent variations in phage type (type 44 to type 29), biotype (type 26a to types 26d, 26bd, 26dgi, 26dz and 26i) and antibiotic sensitivity. A group of 275 non-fimbriate, non-inositol-fermenting and non-rhamnose fermenting (FIRN) strains, particularly associated with avian infections and thought to be clonal in origin, contained 27 phage types and 22 full biotypes in the primary biotypes 29-32.

Bacteriophage Typing

Clonal distribution of resistance plasmid-carrying Salmonella typhimurium, mainly in the Middle East.

Strains of Salmonella typhimurium of predominantly Middle Eastern origin, but distributed from England to India, were found to carry at least three types of resistance plasmid. The most important was initially identified as an F(I) plasmid by compatibility tests, but differs from the F factor on the one hand and the F(I) factors R162 and ColV on the other. The three groups of F(I) plasmids can be distinguished by their compatibility reactions with the MP10 plasmid of S. typhimurium (Smith, Humphreys, Grindley, Grindley & Anderson, 1973) and group H(1) factors: the F factor is unilaterally incompatible with group H(1) (Smith, Grindley, Humphreys & Anderson, 1973; Anderson, 1975b); the F(I) factors are compatible with MP10 and group H(1); and F(I)me factors are incompatible with MP10 but compatible with H(1). The majority of S. typhimurium cultures belonged to phage type 208; most of those that did not, belonged to types related to 208. Only a minority of their F(I)me plasmids were autotransferring. The remainder were mobilizable by F-like plasmids, and by group H(1) and H(2) factors, but not by the fi(-) I(1) factor Delta, or by plasmids of the I(2), B, P, W, N and com 7 groups. The compatibility reactions of the autotransferring F(I)me plasmids were identical with those of the non-transferring members of the group, and both were large, single-copy plasmids.The S. typhimurium strains of this series carried A or AK, and SSu resistance determinants: small, probably multicopy, non-transferring plasmids similar to those originally described in phage type 29 of S. typhimurium (Anderson & Lewis, 1965b).These S. typhimurium cultures probably represent a clone of wide geographical distribution. The accurate epidemiological study of such clonal outbreaks requires, in addition to phage typing, precise identification of the plasmids harboured by the epidemic strains, and may have to be carried to the molecular level.F(I)me plasmids were identified in other drug-resistant salmonellas, notably in a strain of S. wien which caused large outbreaks of mainly paediatric infection in Algeria, and also spread to Britain. An F(I)me plasmid was found in S. typhi phage type 44 from Algeria, in which the phage-restricting properties of the plasmid are responsible for the specificity of the type.

Ampicillin

Bacteriophage-typing designations of Salmonella typhimurium.

The phage-typing scheme of Callow (1959) has been extended. The original number of types was 34; this has now risen to 207. Tables are presented which show the provisional type designations and the definitive designations now being introduced.

Bacteriophage Typing

Mutagenesis of plasmid DNA with hydroxylamine: isolation of mutants of multi-copy plasmids.

An investigation of in vitro mutagenesis of plasmid DNA with hydroxylamine is described. The treated plasmid DNA was used to transform Escherichia coli K12. Mutants of the plasmid NTP3, which codes for resistance to ampicillin and sulphonamides, were isolated and characterised. They were classified according to the reduction in level of their beta-lactamase activity. Hydroxylamine-induced mutants of NTP14 were also isolated. This plasmid codes for ampicillin resistance, synthesis of colicin E1, and the EcoRI restriction and modification enzymes. One class of mutants is lethal to the host strain at temperatures above 33 degrees C, but carrier strains grow well at 28 degrees C. There is evidence that these mutants code for a temperature-sensitive EcoRI modification activity: the lethal effect probably results from the cleavage of the host-cell DNA by the restriction enzyme at non-permissive temperatures. The possible genetic uses of the mutant plasmids for the production of hybrid plasmids in the bacterial cell are discussed.

Ampicillin

Characterisation of plasmids coding for the restriction endonuclease EcoRI.

The properties of two plasmids coding for the CcoRI restriction and modification enzymes are described. Both plasmids are non auto-transferring (NTP) but can be mobilised by transfer factors. Strains carrying NTP13 produce colicin E1 and the EcoRI enzymes. This plasmid has a molecular weight of 6 X 10(6) daltons and is present as approximately 12 copies per chromosome. The second plasmid, NTP14, was detected after mobilisation of the EcoRI plasmid with the R factor RI-19. NTP14 codes for ampicillin resistance, synthesis of the EcoRI enzymes and colicin E1. The molecular weight of NTP14 is 10.7 X 10(6) daltons and there are about 14 copies per chromosome. DNA-DNA reassociation experiments were performed to determine the interrelationships of NTP13, NTP14, ColE1 and the R factor R1-19. NTP13 and NTP14 continue to replicate when cellular protein synthesis is inhibited by the addition of chloramphenicol.

Ampicillin

A simple method for the preparation of large quantities of pure plasmid DNA.

Polyethylene glycol quantitatively precipitates plasmid DNA of molecular weight 6-123-10-6, from cleared lysates of plasmid-carrying bacterial strains, After resuspension and density-gradient centrifugation of the precipitated DNA, it is unchanged in length and in transformation efficiency for Escherichia coli K12. Plasmid DNA can be easily prepared in large quantities by including a polyethylene glycol precipitation step in standard plasmid isolation procedures.

Anti-Bacterial Agents

The problem and implications of chloramphenicol resistance in the typhoid bacillus.

Transferable chloramphenicol resistance has become common in the typhoid bacillus in countries such as Mexico, India, Vietnam and Thailand. Situations such as this, and others analogous to it in many parts of the world, are the result of the long-term indiscriminate use of chloramphenicol and other antibiotics in the affected areas. They can be rectified only by more rational antibiotic usage.

Bacteriophage Typing