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Biomedical subjects

J Bennett

Publications and source records attributed to J Bennett.

At least 19 recordsLinked to original sources
PubMed1999

Effect of subclinical infection on maintaining immunity against measles in vaccinated children in West Africa.

BACKGROUND: Despite a high coverage with measles vaccines in parts of west Africa, epidemics of measles occur with reduced severity in an increasing proportion of older children who have been vaccinated. We examined the effect of exposure to natural measles on immunity in vaccinated children. METHODS: Our study was carried out in 1992 during an epidemic of measles in Niakhar, a rural area of Senegal with about 27,000 inhabitants who mostly live in compounds that include several households; within each household people live in different huts. Vaccine coverage in Niakhar was 81% at the time of our study. We measured haemagglutinin-inhibiting antibody at exposure and twice thereafter (after 4-5 weeks and at 6 months) in 36 vaccinated and 87 unvaccinated children. The frequency of measles and subclinical measles--defined as a four-fold or greater rise in antibody titre without clinical signs or symptoms--was related to intensity of exposure according to whether the index case was in the same hut, household, or compound. FINDINGS: Clinical measles occurred in 20 (56%) of 36 unvaccinated children and in one (1%) of 87 vaccinated children. Subclinical measles occurred in 39 (45%) of 86 vaccinated children who were exposed to measles and in four (25%) of 16 unvaccinated children. The frequency was inversely related to pre-exposure antibody concentration (p<0.001 for trend) and directly related to intensity of exposure (p=0.002 for trend). Antibody concentrations in subclinical cases increased on average by 45-fold and remained raised for at least 6 months. INTERPRETATION: Increased antibody titre after subclinical measles may be common in vaccinated children in West Africa where the intensity of exposure is high. As measles vaccination coverage increases, the circulation of wild measles will decrease, and vaccine-induced antibody is less likely to be boosted. Thus, new epidemics, albeit milder in form, may occur in vaccinated areas which should be recognised in campaigns to eradicate measles.

Adolescent↗
PubMed1999

Position of the internal jugular vein in children. A study of the anatomy using ultrasonography.

The relative anatomy of the internal jugular vein (IJV) was studied in 25 patients undergoing cardiac catheterization under general anaesthesia, with the use of a portable ultrasound probe. In 14 of cases the IJV was anterior, 1 anterolateral and in 10 lateral to the carotid artery between the two heads of the sternocleidomastoid muscle. At the level of the cricoid cartilage, in six cases the IJV was anterior, three anterolateral and in 16 of children the IJV was lateral to the carotid artery. When attempting to cannulate the IJV, because of the variability in relationship of the IJV to CA the technique used should be modified depending upon the level at which cannulation is attempted. The position of the IJV in the child appears to be so variable extra care should be taken when cannulating the IJV and it should not be assumed that the techniques used in adults are directly transferable.

Adolescent↗
PubMed1999

Seroconversions in unvaccinated infants: further evidence for subclinical measles from vaccine trials in Niakhar, Senegal.

BACKGROUND: Increases in measles antibodies without rash-illnesses have been documented in previously vaccinated children exposed to measles cases. The phenomenon has been incompletely evaluated in young unvaccinated infants with immunity of maternal origin. METHODS: Monthly cohorts of newborns were prospectively randomized to vaccine and placebo control groups during a trial of high-titre vaccines in Niakhar, Senegal. Measles antibodies were assayed in blood samples of enrolled children collected at 5 months old, when controls received a placebo injection, and at 10 months, when the placebo group was given measles vaccine. Intensive prospective surveillance for measles was conducted throughout the trial. RESULTS: One-fifth (n = 53) of the placebo controls seroconverted, with known exposure to a measles case in only three of them. None of the seroconverters developed a measles-like rash. Sixteen-fold or greater increases in titres were noted in about one-quarter of them. Compared with placebo controls who did not seroconvert, seroconverters were more likely to have had exposure to a measles case and to travel, more likely to be boys than girls, and had significantly lower baseline antibody titres. Measles was endemic in the study area throughout the trial. Seroconversions did not adversely effect subsequent nutritional indices or mortality. CONCLUSIONS: Although laboratory errors and inadvertent injection of vaccine rather than placebo may have played some role, they do not fully explain the above observations, which are consistent with subclinical measles in the seroconverters. The possible role of subclinical measles in occult transmission, its potential effect on the type and duration of subsequent immunity, and its impact on response to primary vaccination need to be determined.

Analysis of Variance↗
PubMed1999

Increased long term mortality associated with rash after early measles vaccination in rural Senegal.

OBJECTIVES: To examine whether clinical symptoms, including rash, were more common after measles immunization compared with placebo and to study the association between postvaccination symptoms and later mortality. DESIGN: Examination of side effects in the 3 weeks after immunization in a trial of high titer and standard titer measles vaccines. PATIENTS: Two hundred twenty-four children randomly selected to be included in the surveillance for diarrhea, fever and rash. RESULTS: There was no difference in fever and diarrhea between recipients of high titer vaccines and recipients of placebo. However, high titer recipients tended to have more measles-like rashes than placebo recipients [relative risk, 2.12 (range, 0.90 to 5.03)]. Among recipients of high titer vaccines, children who presented a rash had higher mortality in the following 5 to 7 years than those who did not develop rash [mortality rate ratio, 3.85 (range, 1.52 to 9.79)]. High titer recipients without a rash had the same mortality as children in the placebo group who were given standard doses of measles vaccine at 10 months of age [mortality rate, 0.76 (range, 0.35 to 1.62)]. CONCLUSIONS: These observations suggest that in this particular study, rash after high titer measles vaccine may identify children who received a particularly high dose of vaccine or children with more severe and persistent postvaccination immunosuppression. Whether high titer vaccine is more likely than standard titer measles vaccine to provoke such reaction is not known, given that we did not compare side effects after different titers of measles vaccine. Future trials of live measles vaccine should monitor the development of rash.

Cause of Death↗
PubMed1999

Poor serologic responses five to seven years after immunization with high and standard titer measles vaccines.

BACKGROUND: Few data exist on the persistence of measles antibodies after vaccination of West African infants. Therefore we examined measles antibody titers 5 to 7 years after children in rural Senegal had received high titer Edmonston-Zagreb (EZ-HT), high titer Schwarz (SW-HT) or standard titer Schwarz (SW-STD) measles vaccines in infancy. METHODS: Children had received either high titer vaccines at 5 months of age or standard titer at 10 months of age. Finger prick blood samples were tested for measles antibody 5 to 7 years later by the hemagglutinin inhibition test. RESULTS: Persistence of antibody after high titer vaccines was poor with the result that 39 and 50% of the EZ-HT and the SW-HT groups had low titers of hemagglutinin inhibition measles antibodies (< or =125 mIU/ml). Nineteen percent of the children in the SW-STD group had low titers which is a lower prevalence than in the high titer groups [relative risk (95% confidence intervals), 0.05 (0.28 to 0.88) vs. EZ-HT; relative risk, 0.38 (0.22 to 0.66) vs. SW-HT]. Geometric mean (95% confidence interval) antibody titers in children with detectable values were 616 (435 to 871) in the EZ-HT, 1106 (616 to 1866) in the SW-HT and 1271 (871 to 1741) mIU/ml in the SW-STD groups, respectively. Multivariant regression analysis showed that mean titers were 2.00 (1.03 to 3.89) times higher for children with low prevaccination antibody titers (< or =125 mIU/ml) and 3.06 (1.90 to 4.94) times higher if blood was collected in the rainy season. INTERPRETATION: Given the rapid decline in antibody titers over a 5- to 6-year period in an area where measles vaccine coverage was high, it seems likely that multiple dose immunization schedules will be needed in the future to maintain protective antibody concentrations (>125 mIU/ml) in West Africa. The role of subclinical boosting by exposure to natural measles and the possible role of malaria, which increases immunoglobulin turnover, in influencing long term antibody persistence after vaccination deserve further investigation.

Antibodies, Viral↗
PubMed1999

Medication adherence in rheumatoid arthritis patients: older is wiser.

OBJECTIVES: To create a profile of individuals nonadherent to their medications in an age-stratified sample (ages 34-84) of community-dwelling rheumatoid arthritis patients. The relative contributions of age, cognitive function, disability, emotional state, lifestyle, and beliefs about illness to nonadherence were assessed. DESIGN: A direct observation approach was used in conjunction with structural equation modeling. All participants were administered a preliminary assessment battery. Medications were then transferred to vials with microelectronic caps that recorded medication events for all medications for the next 4 weeks. PARTICIPANTS AND SETTING: A volunteer sample of 121 community-dwelling rheumatoid arthritis (RA) patients were recruited from newspaper ads, posters, and via informal physician contact from private rheumatology practices in Atlanta and Athens, Georgia. Written verification of the RA diagnosis and a disease severity rating were obtained from personal physicians before patients were enrolled in the study. Patients were tested in a private physician's office, and their medication adherence was monitored electronically for a month in their every-day work and home settings. MEASUREMENTS AND RESULTS: Structural equation modeling techniques were used to develop a model of adherence behavior. Cognitive and psychosocial measures were used to construct latent variables to predict adherence errors. The model of medication adherence explained 39% of the variance in adherence errors. The model demonstrated that older adults made the fewest adherence errors, and middle-aged adults made the most. A busy lifestyle, age, and cognitive deficits predicted nonadherence, whereas coping with arthritis-related moods predicted adherence. Illness severity, medication load, and physical function did not predict adherence errors. Omission of medication accounted for nearly all errors. CONCLUSION: Despite strong evidence for normal, age-related cognitive decline in this sample, older adults had sufficient cognitive function to manage medications. A busy lifestyle and middle age were more determinant of who was at risk of nonadherence than beliefs about medication or illness. Thus, practicing physicians should not assume that older adults have insufficient cognitive resources to manage medications and that they will be the most likely to make adherence errors. Very busy middle-aged adults seem to be at the greatest risk of managing medications improperly.

Adaptation, Psychological↗
PubMed1999

Long-term followup of the North American multicenter UroLume trial for the treatment of external detrusor-sphincter dyssynergia.

PURPOSE: We determine the long-term efficacy and safety of the UroLume stent as minimally invasive treatment for external detrusor-sphincter dyssynergia in spinal cord injured men. MATERIALS AND METHODS: A total of 160 spinal cord injured men with a mean age plus or minus standard deviation of 36.3 +/- 12.1 years (range 16 to 74) were prospectively treated with an endoprosthesis at 15 centers as part of the North American UroLume trial for external detrusor-sphincter dyssynergia. Urodynamic parameters, including voiding pressure, residual urine volume and bladder capacity, were compared before treatment and at 1, 2, 3, 4 and 5 years after treatment. RESULTS: Mean voiding pressure was 75.1 +/- 28.2 cm. water before treatment in the 160 patients, and 37.4 +/- 23.9 at year 1 in 97, 39.5 +/- 22.2 at year 2 in 84, 42.6 +/- 27.3 at year 3 in 61, 46.3 +/- 33.2 at year 4 in 57 and 44.2 +/- 28.9 cm. at year 5 in 41 after stent insertion (p <0.001). Residual urine volume decreased after stent placement and was maintained throughout the 5-year followup (p <0.001). Mean cystometric capacity remained constant from 269 +/- 155 before insertion to 337 +/- 182 ml. 5 years later (p = 0.17). Hydronephrosis and autonomic dysreflexia improved or stabilized in most patients with functioning stents. Stent explant was necessary in 24 patients (15%), of whom 4 (16.7%) had another stent implanted. CONCLUSIONS: The UroLume stent demonstrates long-term safety and efficacy for the treatment of external detrusor-sphincter dyssynergia. The outcome was similar in men with and without previous sphincterotomy.

Adolescent↗
PubMed1998

Surgical correction of an acquired vaginal stricture in a llama, using a carbon-dioxide laser.

An acquired vaginal stricture in a llama secondary to trauma from uterine torsion during gestation was repaired, using a carbon-dioxide laser. The procedure was accomplished by use of epidural anesthesia with the llama in a standing position. Repeated dilation of the vagina was required after surgery; however, the llama subsequently mated and conceived, and a male cria was delivered by cesarean section at the end of a full-term gestation.

Animals↗
PubMed1998

Temporal and spatial regulation of gene expression mediated by the promoter for the human tissue inhibitor of metalloproteinases-3 (TIMP-3)-encoding gene.

A complex interplay between enzymes involved in extracellular matrix formation and their inhibitors is thought to control organogenesis during mammalian development. Disturbance of this balance may result in a wide range of diseases, including macular degeneration, arthritis, and tumor metastases. In order to define elements which may be involved in regulating human tissue inhibitor of metalloproteinase 3 (TIMP3) expression, we isolated and sequenced a clone containing 1315 bp of the 5'-upstream region of the human TIMP-3-encoding gene. A 1.2 kb fragment of this clone, which contains multiple motifs which are binding sites for known transcription factors, was used to drive expression of the lacZ reporter gene in multiple lines of transgenic mice. TIMP3 promoter activity, detected through beta-galactosidase histochemical assay, was observed at high levels in selected tissues, the identity of which varied according to developmental stage. TIMP3 promoter activity was detected at embryonic and early postnatal stages in tissues undergoing extensive remodeling, such as developing somites, bones and joints, choroid plexus, webs between the digits, and the spongiotrophoblastic portion of the placenta. In adulthood, TIMP3 promoter activity was restricted to a few tissues which exhibit high metabolic activity or rapid turnover. These include the retinal pigment epithelium (RPE), cells of the kidney cortex, hair follicles, gingiva, ovarian follicles, and testis. The results suggest that TIMP3 expression plays an active role in developmental patterning and in the maintenance of specific differentiated tissues.

Animals↗
PubMed1998

Developing guidelines for community child health staff and examining the referral pathways and outcomes of care in the support of emotionally and behaviourally disturbed children.

The East Sussex Public Health Commissioners had enquired whether referral guidelines were needed to ensure that the children with the greatest concerns achieved support from the Child and Adolescent Mental Health Services (CAMHS). Community child health doctors and nurses recorded all contacts with children with emotional and behavioural difficulties (EBD) over a one month period. Data on presenting difficulties and on intervention pathways were recorded. The same children were reviewed five months later and the outcome was measured by clinical assessment and by support offered. The work showed that child health staff were managing cases both through single advisory sessions and through planned on-going support. Additionally, the use of the three tier pathways recommended by the Department of Health was demonstrated. Analysis of recorded data was used to describe referral pathways and to give guidance on the characteristics of children who needed referral to CAMHS.

Attention Deficit and Disruptive Behavior Disorder↗
PubMed1998

Adverse impact of infections on antibody responses to measles vaccination.

Antibody titres were determined in 102 Thai infants who were vaccinated at 9-months of age during the respiratory disease season. The symptom densities of illnesses at or following vaccination, including rhinorrhea and diarrhea, were significantly lower among seroconverters, although the simple presence or absence of specific symptoms was not significantly related to seroconversions. Logistic regression indicated that neutralization test antibody titres below the median titre of 1:80 following vaccination were significantly more frequent among those with rhinorrhea when vaccinated and among those with diarrhea after vaccination. Compared with a referent group without these symptoms, titres were lower in those who had rhinorrhea when vaccinated, rhinorrhea during the first week post vaccination, and diarrhea in either of the two follow-up weeks. Illnesses concurrent or subsequent to measles vaccination adversely affected antibody responses in these study objects.

Antibodies, Viral↗
PubMed1998

Incremental bolus versus a continuous infusion of propofol for deep sedation/general anesthesia during dentoalveolar surgery.

PURPOSE: This article compared the use of the traditional incremental bolus technique with the continuous infusion technique for the administration of propofol for deep sedation/general anesthesia. PATIENTS AND METHODS: Patients were sedated with midazolam and fentanyl and then had maintenance of an anesthetic state achieved with propofol administered by either of the two techniques. Data were collected to evaluate the overall surgical/anesthetic procedure, movement of the patient, and his or her hemodynamic status. RESULTS: Both groups received a mean maintenance dose of propofol exceeding 6 mg/kg/hr. However, the patients in the continuous infusion group received a statistically greater maintenance dose (continuous infusion + supplemental vs incremental bolus). All patients were maintained in a deep sedation/general anesthetic state. Respiratory and blood pressure values were comparable in both groups. However, the continuous infusion group showed improved hemodynamic stability manifested as fewer fluctuations in heart rate. Visual analog scale (VAS) questionnaires completed by the surgeon and surgical assistant reported less patient movement and improved surgical/anesthetic conditions with the continuous infusion technique. Recovery of the two groups was comparable. CONCLUSION: This study, although finding advantages in the continuous infusion technique, showed satisfactory conditions associated with both techniques.

Alveolar Process↗
PubMed1998

Subcutaneous administration of midazolam: a comparison of the Bioject jet injector with the conventional syringe and needle.

PURPOSE: The purpose of this study was to compare jet injection to a syringe and needle in terms of the difference in discomfort and pharmacokinetics after the subcutaneous administration of midazolam. PATIENTS AND METHODS: Using a prospective, randomized, double-blinded study design, 14 subjects were administered midazolam on two separate occasions (at least 2 weeks apart). The subjects were randomly distributed into two groups: syringe and needle (saline)/jet injector (midazolam) or syringe and needle (midazolam)/jet injector (saline). The subjects were randomly assigned to receive either EMLA (eutectic mixture of local anesthetics) or a placebo at the injection site for the first administration and the other topical agent on the second visit. Each subject received one subcutaneous injection in the deltoid region per arm per day. Each injection contained the same volume of solution. Subjects completed visual analog scale (VAS) questionnaires assessing the discomfort of the injection. Blood samples were taken at specified intervals over 2 hours for determination of midazolam levels. RESULTS: The discomfort associated with the injection was less with the Biojector 2000 (Bioject Inc, Portland, OR) although this was not statistically significant. However, persistent discomfort was significantly greater at the needle site. The mean peak plasma level of midazolam was achieved more rapidly with the Biojector 2000 than with the syringe and needle (P < .05). However, the peak plasma level after jet injection or injection with a syringe and needle was not statistically different. CONCLUSION: The results of the study show that the Biojector 2000 is a needle-free injection system that can be used for the administration of a premedicant before induction of anesthesia. It has several advantages, including the potential reduction of anxiety associated with the "fear of needles" and occupational injuries.

Adolescent↗
PubMed1998

Laboratory investigation and comparison of Salmonella Brandenburg cases in New Zealand.

An apparent increase in the incidence of S. Brandenburg in New Zealand, coupled with the possibility that the virulence of the organism may also be changing, prompted this study. Three typing methods: macro-restriction fragment length polymorphism (MRFLP) profiling using pulsed field gel electrophoresis (PFGE), plasmid profiling and antimicrobial susceptibility profiling were used to determine strain diversity amongst 115 recent and historical isolates of S. Brandenburg from both human cases and non-human sources. Antimicrobial resistance was noted only in three isolates. Plasmids of varying sizes were found in 31 isolates. MRFLP analysis resulted in 13 different patterns. Combining the three sets of typing data yielded 24 composite types. Comparison of composite type, isolation date and geographical location of case allowed the retrospective recognition of seven potential clusters during the 5-year study period. Composite types of 24 (80%) of the non-human isolates tested were indistinguishable from human isolates, suggesting that human infection may be via a number of vehicles. Although not cost-effective for routine use on all salmonella isolates, the methods used in this study are an important adjunct to serotyping for discrimination within an emerging serotype.

DNA, Bacterial↗
PubMed1998

Adenovirus-mediated delivery of rhodopsin-promoted bcl-2 results in a delay in photoreceptor cell death in the rd/rd mouse.

Gene transfer to retinal cells may provide a means to retard photoreceptor cell death and thus prevent blindness in diseases such as retinitis pigmentosa. We tested the possibility of interfering with apoptotic photoreceptor cell death in the rd mouse through subretinal delivery of a recombinant replication-defective adenovirus containing the human cDNA for bcl-2, Ad.2.5HRPbcl-2. Photoreceptor-specific transgene expression was accomplished through incorporation of the 2.5 kb human rhodopsin upstream fragment (HRP). Ad.2.5HRPbcl-2 was injected alone or in combination with Ad.CMVPDE beta. Ad.CMVPDE beta contains a cDNA encoding the beta subunit of cGMP phosphodiesterase (PDE beta). Recombinant viruses containing lacZ (driven either by the cytomegalovirus (CMV) promoter/enhancer or HRP) and of Ad.CMVPDE beta and vehicle alone were injected in contralateral eyes as control. Injection of Ad.2.5HRPbcl-2 in the rd mouse resulted in histologically detectable rescue lasting 6 weeks after birth. Extent of rescue was not as large as after delivery of wildtype PDE beta, the gene defective in the rd mouse. However, delivery of genes which prevent apoptotic cell death may have broad application to gene therapy of retinal degenerative diseases.

Adenoviridae↗