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Biomedical subjects

D Taylor

Publications and source records attributed to D Taylor.

At least 199 records · Page 11Linked to original sources
PubMed1997

Risk factors for adult paternity in births to adolescents.

OBJECTIVE: To examine the risk factors for adult (aged 20 years and older) paternity in births to teenagers (14-17 years of age). METHODS: This was a population-based, retrospective cohort analysis of 27,215 adolescent mothers residing in California who had a live singleton birth during 1993. Adjusted risks for adult paternity by paternal and maternal characteristics were derived from comparisons of adult-teen and teen-teen couples. RESULTS: Adult fathers, who were responsible for 49.2% of births to teenage mothers, were a mean of 6.4 years older than the mother. The most important risk factors for adult paternity were as follows: father's (odds ratio [OR] 5.19; 95% confidence interval [CI] 4.43, 6.08) or mother's (OR 1.33; 95% CI 1.14, 1.55) educational attainment of at least 3 years lower than expected for their age, two or more previous live births (OR 3.34; 95% CI 2.48, 4.53), mother's birthplace outside the United States (OR 2.33; 95% CI 2.11, 2.58), father's (OR 2.16; 95% CI 1.98, 2.36) or mother's (OR 1.28; 95% CI 1.15, 1.42) educational attainment 1-2 years lower than expected for their age, one previous live birth (OR 1.92; 95% CI 1.75, 2.12), and Asian (OR 1.29; 95% CI 1.04, 1.62) or African American race (OR 1.25; 95% CI 1.06, 1.46) of the father. CONCLUSIONS: Teenage pregnancy prevention programs must address adult paternity, which contributed to almost half of the births in our study. These programs should consider education adequacy, cultural beliefs and practices, previous live births, and race and ethnicity when designing programs to decrease the number of adults involved in teenage births.

Adolescent↗
PubMed1997

Umbilical cord blood interleukin-6 levels and neonatal morbidity.

OBJECTIVE: To study umbilical cord interleukin-6 levels and the occurrence of neonatal sepsis, congenital pneumonia, necrotizing enterocolitis, and grade II-IV intraventricular hemorrhage. METHODS: Umbilical cord blood was collected from 133 preterm newborns. The study population was divided according to the presence or absence of neonatal complications. Interleukin-6 levels and clinical characteristics were compared by univariate and multivariate analyses. RESULTS: Sixteen neonates had adverse outcomes, and 117 were unaffected. The median interleukin-6 level was significantly higher in affected than in unaffected infants (145 pg/mL versus 0 pg/mL, P = .002). Elevated interleukin-6 levels were associated independently with neonatal morbidity in multiple logistic regression modeling that included gestational age, birth weight, and antenatal steroid exposure. CONCLUSION: Umbilical cord blood interleukin-6 levels are elevated in neonates who subsequently develop sepsis, congenital pneumonia, necrotizing enterocolitis, or grade II-IV intraventricular hemorrhage.

Adult↗
PubMed1997

Computer prediction of adaptive bone remodelling around noncemented femoral prostheses: the relationship between damage-based and strain-based algorithms.

Several mathematical models to predict tissue adaptation have been derived since Julius Wolff proposed a function-form relationship for bone. These can be formulated as computational procedures (algorithms) to predict bone adaptation around implants. The objective of this paper was to further develop the damage-adaptive algorithm, to test its validity, and to determine the relationship between it and algorithms based on strain energy. This was achieved using finite element models of the proximal femur, one for the intact case and another for the case where a noncemented hip prosthesis is implanted. The finite models were generated using CT scan data. Initial bone resorption patterns around a femoral prosthesis following total hip arthroplasty were computed for both damage-adaptive and strain-adaptive adaptation rules. It is found that the damage-adaptive algorithm can successfully predict the bone's adaptive behaviour in response to altered mechanical loading provided that account is taken of the nonlinear nature of damage accumulation. Predictions are made using a strain energy stimulus for comparison with the damage stimulus, and a theoretical relationship between the two is proposed. It is shown that an advantage of the damage approach over the strain-based approach is that the nonlinearity required to replicate clinically observed resorption patterns can be derived theoretically, whereas for strain-adaptive remodelling, empirical relationships are assumed.

Adaptation, Physiological↗
PubMed1997

Thrombopoietin measurement in thrombocytosis: dysregulation and lack of feedback inhibition in essential thrombocythaemia.

Essential thrombocythaemia (ET), a myeloproliferative disorder (MPD) manifested by excessive platelet production, lacks a specific diagnostic test to facilitate differentiation from other thrombocytoses. We studied thrombopoietin (TPO) levels in 41 patients with thrombocytosis: 25 ET patients, eight with other MPD, and eight with reactive thrombocytosis. Mean age and platelet counts for these groups were comparable. TPO levels for 96 healthy individuals provided a reference range for normal. The majority of ET patients (19/25 or 76%) had normal TPO levels. No patient with ET had a TPO level below 75 pg/ml, compared with 57% of healthy donors and 8/16 (50%) patients with other thrombocytoses (P<0.05). TPO levels in ET are not appropriately down-regulated, as occurs with cytokines relevant to other MPD. In thrombocytosis, a TPO level <75 pg/ml indicates that ET is unlikely.

Adolescent↗
PubMed1997

Successful control of Clostridium difficile infection in an elderly care unit through use of a restrictive antibiotic policy.

Toxin-producing Clostridium difficile is the commonest bacterial cause of nosocomial diarrhoea and is a well recognized cause of hospital outbreaks in elderly care units. High C. difficile disease rates have been associated with the use of broad-spectrum antibiotics, especially cephalosporins. An outbreak of C. difficile infection in the elderly care unit at Gloucestershire Royal NHS Trust continued despite increased ward cleaning and strict implementation of infection control measures. A restrictive antibiotic policy that would maintain colonization resistance in the gastrointestinal tract was introduced throughout this unit. Patients admitted with suspected infection were prescribed intravenous (i.v.) benzylpenicillin 1.2-1.8 g every 6 h to cover streptococcal infections and i.v. trimethoprim 200 mg twice daily to cover urinary tract pathogens and Haemophilus influenzae. If the patient had septic shock a single iv dose of gentamicin was given (120-180 mg) to cover more resistant gram-negative bacilli. The following were monitored before and after the policy change. The number of cases of C. difficile toxin-positive diarrhoea; cefuroxime and total antibiotic use on the elderly care wards; patient mortality rates; and length of hospital stay: two hundred and fifty-two and 234 patients respectively with a discharge diagnosis of infection were admitted before and after the antibiotic policy change. Mortality rates and length of hospital stay were unchanged. Cefuroxime prescribing and total antibiotic prescribing costs fell by 5150 pounds sterling and 8622 pounds sterling respectively in the 7 month period after the change. Thirty-seven cases of C. difficile diarrhoea occurred in the period before and 16 in the period after the policy change. The incidence of C. difficile diarrhoea and of cefuroxime use has remained low since then. The use of narrow-spectrum antibiotics for hospital treatment of community-acquired infections in the elderly should be encouraged. Outbreaks of C. difficile diarrhoea should be managed with the combined approach of infection control and strict antibiotic policies.

Aged↗
PubMed1997

Smooth pursuit development in infants.

PURPOSE: We set out to assess the development of pursuit eye movements in normal infants in an objective, longitudinal fashion. We asked whether smooth pursuit (SP) was present under 2 months of age and how the saccade ratio changed with increasing infant age. METHODS: Smooth pursuit was recorded longitudinally from 25 infants aged 1-7 months, using DC electro-oculography, in a clinically practical manner. Four uninstructed adults acted as controls. RESULTS: Smooth pursuit was present under 2 months of age. The gain of SP increased with increasing infant age. However, it had still not reached adult levels by 6 months of age. Latency decreased with increasing infant age. Monocular SP asymmetry was present in the younger infants. CONCLUSIONS: Smooth pursuit is present under 2 months of age, but at 6 months SP has still not reached adult levels. The traditional model of SP development is questionable.

Child Development↗
PubMed1997

Demography of assault in a provincial Victorian population.

The study examined the frequency and patterns of assault within a large regional population of Victoria. The records of 860 victims of physical assault who presented to the Geelong Hospital emergency department during 1993 and 1994 were analysed retrospectively. The policy data on 1427 reported cases of physical assault, from the same catchment area and over a similar period of time, were also examined. The hospital data revealed that 65 per cent of assault victims were males aged from 15 to 34 years, that 58 per cent of presentations were within four hours of midnight, and 68 per cent were on Friday, Saturday or Sunday. Most assaults occurred on the streets, on footpaths, in open spaces or within dwellings, and the highest incidence was during the summer months. The police data showed similar patterns but from a different population of victims. It also showed an upward trend in the rates of assault in Victorian regional areas. The award-winning Geelong 'Local Industry Accord', a police and community intervention program, may have contributed to the decline in violence, particularly within the Geelong city centre, and has been suggested as a model for other community-based intervention programs. For intervention programs to be successful, the demography of assault within communities must be established and target groups identified. Hospital, police and victim surveys data do not identify accurately the population of assault victims. Improved methods of data collection and compatibility between databases already in existence may provide more accurate statistics upon which intervention programs may be based and their success evaluated.

Adolescent↗
PubMed1997

Comparison of the Gyro C1E3 and BioMedicus centrifugal pump performances during cardiopulmonary bypass.

The compact eccentric inlet port (C1E3) centrifugal blood pump was developed as a cardiopulmonary bypass (CPB) pump. The C1E3 pump incorporated a sealless design with a blood stagnation free structure. The pump impeller was magnetically coupled to the driver magnet in a sealless manner. To develop an atraumatic and antithrombogenic centrifugal pump without a shaft seal junction, a double pivot bearing system was introduced. Recently, a mass production model of the C1E3 was fabricated and evaluated. The ratio of the normalized index of hemolysis (NIH) of the C1E3 was 0.007 g/ 100 L, in comparison to the NIH of the BP-80, 0.018 g/ 100 L, each in a CPB condition of 5 L/min against 325 mm Hg. Both pumps were compared in identical in vitro circuits. To further evaluate the pumps during cardiopulmonary bypass for reliability and function, 6 h of CPB was performed on each of 8 bovines using either the C1E3 or BP-80 centrifugal pump. The BP-80 and C1E3 provided pump flows of 50-60 ml/kg/min without incident. The hemodynamics were stable, and the hematology and biochemistry data were within normal ranges. There were no statistically significant differences between the 2 groups. Concerning the plasma free hemoglobin values, a mass production model of the C1E3 pump had the same hemolysis levels as the BP-80. Our preliminary studies reveal that the C1E3 pump is reliable. Also, the C1E3 will satisfy clinical requirements as a cardiopulmonary bypass pump.

Alanine Transaminase↗
PubMed1997

Assessment of the humoral immune response against Plasmodium falciparum rhoptry-associated proteins 1 and 2.

Naturally occurring antibody responses to Plasmodium falciparum rhoptry-associated proteins 1 and 2 (RAP-1 and RAP-2) were measured with recombinant and parasite-derived forms of the antigens. For comparative purposes, responses to multiple forms of three other malarial antigens were also examined. The sera of 100 Papua New Guineans were screened for antibodies. Eighty-six and 82% of individuals over 30 years of age had antibodies that recognized parasite-derived RAP-1 and RAP-2, respectively. Importantly, we found that recombinant and native antigens share linear epitopes seen by the human immune system; thus, the recombinant proteins may be adequate human immunogens. However, antibodies affinity purified on recombinant RAP-1 reacted with other antigens in addition to parasite-derived RAP-1. Thus, the antigenicity of RAP-1 may have been overestimated previously. The recognition of RAP-1 and RAP-2 correlated with age and with the recognition of recombinant forms of the ring-infected erythrocyte surface antigen, merozoite surface protein 1, and merozoite surface antigen 2 (MSA2) antigens. Antibodies to these antigens appear to be generated in response to the total exposure to malaria of the host. Antibodies to conserved regions of MSA2 had stronger correlations with both age and the recognition of other antigens than did the full-length recombinant MSA2 molecule. In contrast to results with the other antigens, there was no significant difference in the ages of individuals with a certain antibody titer to the full-length recombinant or parasite-derived MSA2 molecule, but antibodies to these two antigens did correlate with parasitemia. For all antigens tested, antibody levels after two infections can approach the peak levels of antibodies obtained in immune individuals.

Adolescent↗
PubMed1997

The scalability of the Rivermead Motor Assessment in acute stroke patients.

OBJECTIVE: To examine the scalability of the Rivermead Motor Assessment with hospitalized acute stroke patients. DESIGN: This was a prospective study of hospitalized stroke patients. SUBJECTS: Fifty-one selected stroke patients, including those over the age of 65, were assessed at one, three and six weeks post-stroke using the Rivermead Motor Assessment. Coefficients of scalability and reproducibility were calculated for each of the three sections of the Rivermead Motor Assessment at each assessment. RESULTS: The items in the gross function and arm sections met scaling criteria at all three assessments which meant that they were in appropriate order of difficulty. There was an overall increase in the proportion of subjects passing each item at successive assessments, suggesting that patients in the study were recovering. The leg and trunk section did not meet scale criteria with these acute stroke patients. CONCLUSIONS: We recommend that only the gross function and arm sections should be used as hierarchical scales with selected acute stroke patients. The leg and trunk section should only be used as an assessment checklist.

Activities of Daily Living↗
PubMed1997

Acute disturbed or violent behaviour: principles of treatment.

Acute disturbed or violent behaviour has a number of organic, iatrogenic and psychological precipitants and is commonly encountered. Various models have been used to define such behaviour and to suggest non-pharmacological treatments. However, drugs are frequently used and a wide variety of regimens are employed. Robust research into the use of drugs in acute, disturbed behaviour is scant. Nevertheless a treatment protocol is presented based on primary research, review articles and clinical experience.

Acute Disease↗
PubMed1997

Pharmacokinetic interactions involving clozapine.

BACKGROUND: Metabolism of clozapine is complex and not fully understood. Pharmacokinetic interactions with other drugs have been described but, in some cases, their mechanism is unknown. METHOD: Published trials and case reports relevant to the human metabolism of clozapine and to suspected pharmacokinetic interactions were reviewed. RESULTS: Metabolism of clozapine appears to be largely controlled by the function of the hepatic cytochrome p450IA2 (CYPIA2). Compounds which induce CYPIA2 activity (carbamazepine, tobacco smoke) may reduce plasma clozapine levels. Inhibitors of CYPIA2 (caffeine, erythromycin) have the opposite effect. Drugs which inhibit the hepatic cytochrome p4502D6 (CYP2D6) have also been reported to elevate plasma clozapine levels. The mechanism of this interaction is unclear. CONCLUSIONS: The co-administration of clozapine and compounds reported to alter its metabolism should be avoided where possible. A host of other interactions can be predicted and so caution should be exercised when co-administering drugs which affect the function of CYPIA2 and CYP2D6. The pharmacokinetics of clozapine require further investigation so that its safe use can be assured.

Anti-Bacterial Agents↗
PubMed1997

A model for fatigue crack propagation and remodelling in compact bone.

The process of fatigue in bone is of interest for a number of reasons. Fatigue damage in vivo can eventually lead to stress fracture, and may also act as a stimulus for bone remodelling and adaptation. The aim of this paper is to develop a theoretical model which describes the growth of fatigue cracks, especially of microcracks. The growth behaviour of microcracks is complicated by their interactions with the surrounding microstructure. This problem has been identified by researchers working on fatigue in engineering materials. Their work can be adapted to develop an equation in which the growth rate of cracks is related to applied stress conditions and also to a microstructural parameter, d, which is defined as the spacing of barriers to crack growth. The model can be used to generate stress/life data for comparison with in vitro fatigue experiments. It can also be used to investigate two hypotheses: that microcracking stimulates repair and that the level of fatigue damage can act as a signal to initiate adaptation processes of deposition or resorption.

Adaptation, Physiological↗
PubMed1997

Seeing the forests for the more than the trees.

Assessing the health effects of deforestation is difficult because of the rate at which the world's forests are disappearing. From 1990 to 1995 alone, the world lost a total area of forest cover nearly twice the size of Italy. Deforestation, which is caused by human population growth and encroachment, clearance for agricultural production, and the growing worldwide demand for wood products, has been linked with effects ranging from local changes in climatic and disease patterns to global climate change and biodiversity loss. Deforestation is responsible for about 25% of net annual releases of carbon dioxide into the atmosphere and also lessens the amount of forest available to absorb greenhouse gas emissions. Deforestation also causes a tremendous loss of biodiversity worldwide. It is estimated that over the next 50 years deforestation will rank as the single greatest cause of species loss.

Communicable Diseases↗