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J Pearson

Publications and source records attributed to J Pearson.

At least 91 records · Page 5Linked to original sources
PubMed1995

Evolution of spinal bone loss and biochemical markers of bone remodeling after menopause in normal women.

The main objective of this study was to describe longitudinal patterns of spinal bone loss in normal women who undergo a natural menopause. The second objective was to determine if a proportion of women suffer excessively rapid postmenopausal bone loss from the spine. If this was the case it was the aim to devise a means of predicting the woman at excess risk; but if all women lost bone at similar rates, the aim was to document changing loss rates over the first 5-8 postmenopausal years. Responding women in six suburban general practices recalled for cervical smears who had their last menstrual period 9- 36 months previously were invited to participate in a longitudinal study of bone loss and the biochemical markers plasma osteocalcin and urinary hydroxyproline. Sixty-four subjects agreed to participate, a response rate of 80%. In the ensuing 5 years, six received hormone replacement therapy and are not reported on. The main outcome measures were rates of spinal bone loss over 5 years, measured by dual photon absorptiometry, and radial bone loss over the first 2 years measured to quantitative computed tomography. Spinal bone loss was similar between individuals, with 94% of the variability in the data being accounted for by a statistical model that assumed parallel rates of bone loss. A less restrictive model allowing women to have different rates of spinal bone loss accounted for 12% more of the remaining variance in the data than the previous model. However, rates of radial bone loss were more dissimilar between women than rates of spinal loss. The results of the biochemical data collected serially showed that the plasma osteocalcin rose slowly to a plateau at 5 years postmenopause; in contrast, the hydroxyproline fell progressively with time over the whole period of study. These results were interpreted as being consistent with diminishing rates of bone destruction which gradually reequilibrated with bone formation as time passed after menopause.

Absorptiometry, Photon↗
PubMed1995

Household family structure and children's aggressive behavior: a longitudinal study of urban elementary school children.

The relationship between contemporary household family structures at fourth-grade and sixth-grade parent- and teacher-rated aggression was examined in an epidemiologically defined population of urban school children. The relationship between family structure and aggression varied by child gender and by parent and teacher ratings in the home and school, respectively. After taking into account family income, urban area, and fourth-grade aggressive behavior, boys in both mother-father and mother-male partner families were significantly less likely than boys in mother-alone families to be rated as aggressive by teachers. No significant relations between family structure and teacher- or parent-rated aggression were found for girls.

Aggression↗
PubMed1995

European semi-anthropomorphic spine phantom for the calibration of bone densitometers: assessment of precision, stability and accuracy. The European Quantitation of Osteoporosis Study Group.

Up to now it has not been possible to reliably cross-calibrate dual-energy X-ray absorptiometry (DXA) densitometry equipment made by different manufacturers so that a measurement made on an individual subject can be expressed in the units used with a different type of machine. Manufacturers have adopted various procedures for edge detection and calibration, producing various normal ranges which are specific to each individual manufacturer's brand of machine. In this study we have used the recently described European Spine Phantom (ESP, prototype version), which contains three semi-anthropomorphic "vertebrae" of different densities made of stimulated cortical and trabecular bone, to calibrate a range of DXA densitometers and quantitative computed tomography (QCT) equipment used in the measurement of trabecular bone density of the lumbar vertebrae. Three brands of QCT equipment and three brands of DXA equipment were assessed. Repeat measurements were made to assess machine stability. With the large majority of machines which proved stable, mean values were obtained for the measured low, medium and high density vertebrae respectively. In the case of the QCT equipment these means were for the trabecular bone density, and in the case of the DXA equipment for vertebral body bone density in the posteroanterior projection. All DXA machines overestimated the projected area of the vertebral bodies by incorporating variable amounts of transverse process. In general, the QCT equipment gave measured values which were close to the specified values for trabecular density, but there were substantial differences from the specified values in the results provided by the three DXA brands. For the QCT and Norland DXA machines (posteroanterior view), the relationships between specified densities and observed densities were found to be linear, whereas for the other DXA equipment (posteroanterior view), slightly curvilinear, exponential fits were found to be necessary to fit the plots of observed versus specified densities. From these plots, individual calibration equations were derived for each machine studied. For optimal cross-calibration, it was found to be necessary to use an individual calibration equation for each machine. This study has shown that it is possible to cross-calibrate DXA as well as QCT equipment for the measurement of axial bone density. This will be of considerable benefit for large-scale epidemiological studies as well as for multi-site clinical studies depending on bone densitometry.

Absorptiometry, Photon↗
PubMed1995

Physiological indicators and susceptibility of plants to acidifying atmospheric pollution: a multivariate approach.

Plant susceptibility to acidifying atmospheric pollution was investigated for a wide range of plant species under normal environmental conditions. Physiological and biochemical parameters were recorded for each plant species. Multivariate analysis using hierarchical clustering, principal component analysis ordination, as well as regression analysis were used to interpret the data. Analysis of the data separated plants into pioneer tree species, ruderal herbaceous species and climax, slow growing species. Pioneer and ruderal species showed higher potential for foliar nitrate assimilation coupled with higher base cation content and a tendency to a more neutral leaf pH than climax species. Acidic buffering capacities for leaf tissue from pioneer and ruderal species were higher than those of climax species. Nitrate assimilation produces hydroxyl ions, which in conjunction with high base cation content and more neutral leaf pH, provides better metabolic buffering and therefore make pioneer and ruderal species less susceptible to acidifying inputs. Climax species are less able to buffer against acidifying inputs and are subsequently more prone to acidifying air pollution damage.

Journal Article↗
PubMed1995

Dual X-ray absorptiometry--cross-calibration and normative reference ranges for the spine: results of a European Community Concerted Action.

Bone density measurements by dual X-ray absorptiometry (DXA) of the spine can now be made precisely, but there is no uniformity in reporting results and in presenting reference data. A European Union Concerted Action therefore devised a uniform procedure for cross-calibrating and standardizing instruments, using the European spine phantom (ESP) prototype. This phantom differs in a number of respects from the final version of the ESP. Eighteen centers in nine countries obtained 1619 records (1035 women) from Caucasian subjects, aged 20-80 years, drawn from normal populations. The DXA machines used were made by the Hologic, Lunar, and Norland companies. Highly statistically significant differences were evident between populations, both in apparent rates of bone loss with age and in the spread of values about the age-adjusted means. There were small residual differences in the results obtained with the three machine brands which could have been due to the relatively large between-center population differences we observed. The alternative or additional explanation that they were attributable, in part, to the design differences between the ESP prototype and the definitive ESP, which became available after this study was completed, was shown to be a valid possibility. Results from postmenopausal women reported in relation to the years that have elapsed since menopause showed reduced population variance when compared with conventional reporting in relation to age. After cross-calibration, the center with the highest age-adjusted normal density value averaged 23% more than the center with the lowest. It is therefore crucially important to select appropriate reference data in clinical and epidemiological studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Integrated clinical database in a health maintenance organization.

This paper describes the development and implementation of the first phase of a comprehensive clinical information system in the Kaiser Permanente Northwest Region. This system integrates information from disparate departmental systems into a single clinical database. By using periodic batch downloads of patient data from departmental systems into the clinical database, rather than requiring real-time updates, we have been able to implement this system with relative ease and speed. It contains patient demographics, lab, outpatient pharmacy, radiology, pathology, dictated consults, admission histories and physicals, discharge summaries, and other dictated reports for over 380,000 Health Plan Members. The system is fast, intuitive, reliable, and user-friendly. In March 1994, there were approximately 1,600 active users. These individuals accounted for approximately 410,000 transactions in the month, with an average daily transaction volume of 11,450. Quantifiable cost-savings, in terms of decreased chart pulls and decreased phone calls for information, have offset the cost of development and implementation to some extent. Less quantifiable improvements in the quality of care and the associated cost-savings may eclipse the quantifiable benefits. This system lays the foundation for our clinical information system efforts.

Health Maintenance Organizations↗
PubMed1994

Fluorine-19 nuclear magnetic resonance spectroscopic study of fluorophenylalanine- and fluorotryptophan-labeled avian egg white lysozymes.

We report the 470-MHz (11.7 T) 19F solution nuclear magnetic resonance (NMR) spectra of 2-, 3-, and 4-fluorophenylalanine incorporated into the egg white lysozymes (EC 3.2.1.17) of chicken, pheasant, and duck, as well as spectra of 4-fluorotryptophan incorporated into chicken, California valley quail, and Bob White quail and 5- and 6-fluorotryptophan-labeled chicken lysozyme. The 19F solution NMR spectrum of [4-F]Phe hen egg white lysozyme (HEWL) consists of three sharp resonances, which span a total chemical shift range of 4.8 ppm (at p2H = 6.1). For [3-F]Phe HEWL, the chemical shift range is much smaller, 1.0 ppm (at p2H = 5.9), due presumably to the occurrence of fast phenyl ring flips about the C beta-C gamma bond axis. For [2-F]Phe HEWL, six resonances are observed, spanning a chemical shift range of 7.4 ppm (at p2H = 5.8), due to slow C beta-C gamma ring flips, i.e., both ring-flip isomers appear to be "frozen in" because of steric hindrance. Rotation of the [2-F]Phe residues remains slow up to 55 degrees C (p2H = 4.7). With the [F]Trp-labeled proteins, we find a maximal 14.6-ppm shielding range for [4-F]Trp HEWL but only a 2.8- and 2.4-ppm range for [5- and 6-F]Trp HEWL, respectively, due presumably to increased solvent exposure in the latter cases. Guanidinium chloride denaturation causes loss of essentially all chemical shift nonequivalence, as does thermal denaturation. Spectra recorded as a function of pH show relatively small chemical shift changes (< 1.4 ppm) over the pH range of approximately 1.2-7.8.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Abnormal bacterial colonisation of the genital tract and subsequent preterm delivery and late miscarriage.

OBJECTIVE: To find out whether women with bacterial vaginosis detected early in pregnancy are at increased risk of preterm delivery. DESIGN: Prospective description cohort study. SETTING: Antenatal clinic in a district general hospital. SUBJECTS: 783 women examined during their first antenatal clinic visit and screened for recognised risk factors for preterm delivery and the presence of bacterial vaginosis or intermediate abnormal flora detected by examination of a vaginal smear stained by Gram's method. MAIN OUTCOME MEASURES: Gestational age at delivery classified as late miscarriage (16-24 weeks' gestation), preterm delivery (24-37 weeks' gestation), term delivery (> or = 37 weeks' gestation). RESULTS: Multiple logistic analysis showed that there was an increased incidence of preterm delivery in women with a previous preterm delivery (9/24; odds ratio 25; 95% confidence interval 9 to 70; P < 0.001) and bacterial vaginosis (9/115; 2.8; 1.1 to 7.4; P = 0.04). A further logistic analysis of data from women recruited before 16 weeks' gestation showed that preterm deliveries or late miscarriages occurred more often in women with bacterial vaginosis (12/77; 5.5; 2.3 to 13.3; P < 0.001). CONCLUSIONS: Late miscarriage and preterm delivery are associated with the presence of bacterial vaginosis in early pregnancy. This is independent of recognised risk factors such as previous preterm delivery.

Abortion, Spontaneous↗
PubMed1994

Prognostic factors in upper gastrointestinal bleeding.

In this study we examined factors of possible prognostic value about outcome in a consecutive series of 2217 patients with hematemesis and melena. Death occurred in 189 (8.5%) patients, and 243 (11%) patients experienced rebleeding. Death was significantly associated with rebleeding, age over 60 years, and the finding of blood in the stomach at endoscopy. Rebleeding was significantly associated with melena, identification of a gastric or duodenal ulcer, endoscopic stigmata of hemorrhage such as blood, clot, and active bleeding, and the finding of shock at admission. However, female gender, previous history of ulceration, or indigestion of ulcerogenic drugs, especially nonsteroidal antiinflammatory drugs, were poor predictors of either death or rebleeding. We conclude that the identification of patients at a high risk could contribute to improved management of patients with gastrointestinal bleeding, including early therapeutic intervention.

Aged↗
PubMed1994

An evaluation of a new teenage clinic and its impact on teenage conceptions in Nottingham from 1986 to 1992.

A new contraceptive clinic for teenagers was developed in the centre of Nottingham from 1987 to 1992 and provided care for over 1500 young people in its first three years. Twenty-five percent of clients were aged 16 years and 32% aged 15 or younger. Sixty-seven percent were in full-time education and young unemployed people were under-represented. The majority were young women, who came for routine contraception, usually the oral contraceptive or condom. Seventeen percent came for emergency contraception and 8% for abortion counselling and referral. Over the period 1986 to 1992, data on conceptions for teenage women and women aged over 20 years, who were resident in Nottingham Health district, were compared and when corrected for the estimated population showed that there had been no reduction in teenage conception rates; reasons for this are discussed. The value of conception rates as a measure of quality of sexual health care for teenagers is questioned and other more qualitative methods suggested.

Abortion, Induced↗
PubMed1994

Protection from high pressure induced hyperexcitability by the AMPA/kainate receptor antagonists GYKI 52466 and LY 293558.

The neurophysiological effects of 2 novel AMPA/kainate receptor antagonists, GYKI 52466 and LY 293558, on the high pressure neurological syndrome have been investigated in the rat and baboon (GYKI 52466) and rat (LY 293558). Rats were exposed to increasing ambient pressures of helium and oxygen at 3 ATA/min, on one occasion each. GYKI 52466 at 20 mumol/kg i.v. immediately before, followed by 70 mumol/kg/hr i.v. during compression delayed tremor by 85% and myoclonus by 30%, compared with control vehicle, and no side effects were observed. Seizure activity was not affected by any of the doses used. LY 293558 at 36 mumol/kg i.p. delayed tremor and myoclonus (44% and 12%), LY 293558 72 mumol/kg additionally delayed seizure activity (21%). Side effects, principally tranquilization at the higher dose, were also noted. Six baboons were exposed to a maximum pressure of 91 ATA at 0.3 ATA/min, in the same environment, on two occasions. One exposure was treated with an i.v. infusion of GYKI 52466 15.2 mumol/kg/hr, the other with the same volume of control vehicle. Limb and face tremor and myoclonus were delayed and the severity of signs reduced. No seizures were observed in the drug treated group before 91 ATA. EEG changes associated with exposure to pressure were not affected. It is concluded that antagonism at the AMPA/kainate receptor by GYKI 52466 and LY 293558 beneficially alters HPNS signs but in a manner which is dependent on both the drug and species being studied.

Animals↗