Search PubMed⌕ Search

Biomedical subjects

J Warren

Publications and source records attributed to J Warren.

At least 37 records · Page 2Linked to original sources
PubMed2000

Phenylethylthiazolylthiourea (PETT) non-nucleoside inhibitors of HIV-1 and HIV-2 reverse transcriptases. Structural and biochemical analyses.

Most non-nucleoside reverse transcriptase (RT) inhibitors are specific for HIV-1 RT and demonstrate minimal inhibition of HIV-2 RT. However, we report that members of the phenylethylthiazolylthiourea (PETT) series of non-nucleoside reverse transcriptase inhibitors showing high potency against HIV-1 RT have varying abilities to inhibit HIV-2 RT. Thus, PETT-1 inhibits HIV-1 RT with an IC(50) of 6 nM but shows only weak inhibition of HIV-2 RT, whereas PETT-2 retains similar potency against HIV-1 RT (IC(50) of 5 nM) and also inhibits HIV-2 RT (IC(50) of 2.2 microM). X-ray crystallographic structure determinations of PETT-1 and PETT-2 in complexes with HIV-1 RT reveal the compounds bind in an overall similar conformation albeit with some differences in their interactions with the protein. To investigate whether PETT-2 could be acting at a different site on HIV-2 RT (e.g. the dNTP or template primer binding site), we compared modes of inhibition for PETT-2 against HIV-1 and HIV-2 RT. PETT-2 was a noncompetitive inhibitor with respect to the dGTP substrate for both HIV-1 and HIV-2 RTs. PETT-2 was also a noncompetitive inhibitor with respect to a poly(rC).(dG) template primer for HIV-2 RT. These results are consistent with PETT-2 binding in corresponding pockets in both HIV-1 and HIV-2 RT with amino acid sequence differences in HIV-2 RT affecting the binding of PETT-2 compared with PETT-1.

Binding, Competitive↗
PubMed2000

Fitting in: maintaining a sense of self during hospitalisation.

In this study the patients' perspective of 'fitting in' was gained through participant observation and interviews. Eleven patients' stories confirmed that while hospitalisation can alleviate the suffering caused by illness, it may cause distress. In order to minimise this threat to self patients adjust to hospital life. They are supported by family, friends and health professionals in interpreting the social rules of the ward by conforming to, circumventing and challenging them.

Adaptation, Psychological↗
PubMed2000

Effects of one year of resistance training on the relation between muscular strength and bone density in elderly women.

OBJECTIVES: There is a paucity of long term studies on exercise training in elderly women. The purpose of this study was to investigate the effects of one year of progressive resistance exercise (PRE) on dynamic muscular strength and the relations to bone mineral density (BMD) in elderly women. METHODS: Forty four healthy sedentary women (mean age 68.8 years) volunteered for this study and were randomly assigned to either an exercise group or a control group. The exercise group were involved in three one hour sessions a week for 52 weeks of supervised PRE to strengthen the large muscle groups of the body, while the control group were instructed to continue their normal lifestyle. The exercise circuit included three sets of eight repetitions at 75% of one repetition maximum focused on the large muscle groups. BMD was measured by dual energy x ray absoptiometry (Lunar DPX) at the lumbar spine and at three sites in the proximal femur. Other selected parameters of physical fitness were also measured. RESULTS: Statistical analyses (analysis of covariance) showed significant strength gains (p < 0.01) in bilateral bench press (> 29%), bilateral leg press (> 19%), and unilateral biceps curl (> 20%). No significant difference between groups was evident in body weight, grip strength, flexibility, waist to hip ratio, or the sum of eight skinfolds. Significant relations (p < 0.05) were recorded between dynamic leg strength and the BMD of the femoral neck, Ward's triangle, and the lumbar spine. CONCLUSIONS: Significant strength changes, after one year of PRE, were evident in elderly women, and the muscle increases may parallel changes in BMD; however, correlation coefficients were moderate.

Aged↗
PubMed1999

Imaging of asteroid 433 eros during NEAR's flyby reconnaissance

During the 23 December 1998 flyby of asteroid 433 Eros, the Near-Earth Asteroid Rendezvous (NEAR) spacecraft obtained 222 images of Eros, as well as supporting spectral observations. The images cover slightly more than two-thirds of Eros (best resolution is approximately 400 meters per pixel) and reveal an elongated, cratered body with a linear feature extending for at least 20 kilometers. Our observations show that Eros has dimensions of 33 x 13 x 13 kilometers. The volume, combined with the mass determined by the NEAR radio science experiment, leads to a density of 2.5 +/- 0.8 grams per cubic centimeter. This relatively high density, and the presence of an extensive linear feature, suggest that Eros may be a structurally coherent body.

Journal Article↗
PubMed1999

Crime scene analysis and the escalation of violence in serial rape.

The current study examines the crime scene behavior manifest by 108 serial rapists responsible for the perpetration of 565 rapes across various cities within the US. The goal of the current study is to identify which aspects of crime scene behavior reported to law enforcement by the victim are most useful in predicting, early in a series of offenses, which rapists are most likely to escalate into higher and, at times, life threatening levels of violence. Using 58 scales that quantify the verbal, physical, and sexual behavior manifest by a rapist in his interaction with his victim during his first reported rape and 36 modal variables that summarized approach, timing, demographics, and weapon usage across the series of rapes, the study attempts to differentiate between those rapists who escalate in their use of blunt force (Increasers) from those who do not (Non-Increasers). A logistic regression indicates that rapists who are white rather than of minority status and who, at the time of their first reported rape, rape their victims for longer periods of time and use more profanity are more likely to escalate in their level of blunt force than those rapists who do not exhibit these behaviors. The relevance of this type of predictive framework for law enforcement in its attempts to prioritize particular investigations is discussed.

Adult↗
PubMed1999

Development and evaluation of a microprocessor-based ergonomic dosimeter for evaluating carpentry tasks.

This portable and self-contained lightweight microprocessor based Ergonomic Dosimeter is designed to collect continuously postural angles of the torso and the upper arm in the sagittal plane and the number of kneeling activities. Up to 4 h of task performance data can be stored in a non-volatile memory of the dosimeter, which can then be downloaded to a lap-top computer. The portable dosimeter was tested for test-retest reliability, compared with posture data obtained with a computer-based video analysis system and evaluated at a carpenter's apprentices school and at a construction site. The dosimeter was shown to be suitable for collecting posture and kneeling data for a prolonged period at construction sites.

Anthropometry↗
PubMed1999

Effect of age and surgical approach on complications and short-term mortality after radical prostatectomy--a population-based study.

OBJECTIVES: To use population-based data to accurately delineate the types and incidence of complications, risk of readmission, and influence of age and surgical approach on short-term mortality after radical prostatectomy. METHODS: Medicare claims from 1991 to 1994 were used to identify and quantify the types and risks of complications, rehospitalization within 90 days, and mortality at 30 and 90 days after perineal or retropubic prostatectomy. Logistic regression was used to determine the relationships between age, surgical approach, and short-term outcomes while adjusting for potential confounders. RESULTS: On the basis of data from 101,604 men, complications affected 25.0% to 28.8% of patients treated with the perineal or retropubic approach. The retropubic approach had a higher risk of respiratory complications (relative risk [RR] = 1.53, 95% confidence interval [CI] 1.37 to 1.71) and miscellaneous medical complications (RR = 1.77, 95% CI 1.60 to 1.97) and a lower risk of miscellaneous surgical complications (RR = 0.86, 95% CI 0.78 to 0.94). Differences in medically related gastrointestinal complications partially accounted for the differences in miscellaneous medical complications. Rectal injury with the perineal approach was only approximately 1% to 2%. Readmission within 90 days was necessary for 8.5% to 8.7% of patients who underwent the retropubic or perineal approach. The 30-day mortality was less than 0.5% for men aged 65 to 69; it approached 1% for men aged 75 and older. CONCLUSIONS: Complications and readmission after prostatectomy are substantially more common than previously recognized. Notable differences exist in the incidence of respiratory and nonsurgical gastrointestinal complications, although many short-term outcomes are comparable for the two approaches. Older age is associated with elevated surgical mortality and complications.

Age Factors↗
PubMed1999

The impact of geographic accessibility on the intensity and quality of depression treatment.

OBJECTIVES: For depression, this research measures the impact of travel time on visit frequency and the probability of receiving treatment in concordance with AHCPR guidelines. METHODS: The medical, insurance, and pharmacy records of a community-based sample of 435 subjects with current depression were abstracted to identify those treated for depression, to determine the number of depression visits made over a 6-month period, and to ascertain whether treatment was provided in concordance with AHCPR guidelines. A Geographic Information System was used to calculate the travel time from each patient to their preferred provider. Poisson and logistic regression analyses were used to estimate the impact of travel time on visit frequency and guideline-concordance, controlling for patient casemix. RESULTS: In the community-based sample, 106 subjects were treated for depression by 105 different preferred providers. About one-third (30.7%) were treated by a mental health specialist. One average, patients made 2.8 depression visits over the 6-month period. One-third (28.9%) of the patients received guideline-concordant treatment for depression. The average number of visits for those receiving guideline-concordant care was significantly greater than for those not receiving guideline-concordant care (P < 0.01). Travel time to the preferred provider was significantly associated with making fewer visits (P < 0.0001) and having a lower likelihood of receiving guideline-concordant care (P < 0.05). DISCUSSION: For depression, both pharmacotherapy and psychotherapy treatment regimens require frequent provider contact to be effective. This study suggests that travel barriers may prevent rural patients from making a sufficient number of visits to receive effective guideline-concordant treatment.

Adult↗
PubMed1999

The organizational context of non-lethal workplace violence: its interpersonal, temporal, and spatial correlates.

This article examines 993 violent incidents involving faculty, students, and staff that occurred at a highly ranked teaching and research university and its affiliated medical center. Violent incidents were included in the sample if they involved faculty, students, or staff, regardless of their specific location or context (i.e., whether they occurred on campus and/or off-campus and whether they occurred within the context of work or some other activity). The theoretical goal of the project was to compare work-related incidents with non-work-related incidents of interpersonal violence occurring in a single, multifunctioning, and professionally hierarchical organization. Data were collected over a 7-year period from three police departments (city, county, and university), university records, and criminal history records obtained from the state police. The coding protocol was developed to capture crime-scene information pertinent to each of the incidents. This included information about the victim, the perpetrator, the relationship between the victim and perpetrator, and the violent incident. The data were examined using nonparametric statistics and logistic regression to model predictive differences between the workplace and non-workplace incidents. The results suggest that the workplace incidents of violence differ from the non-workplace incidents according to their time, victim age, degree of victim injury, and whether the workplace is a medical location. The authors conclude that these differences are better explained by the movement of people in and out of the workplace who bring societal violence with them, rather than by a category or type of workplace violence.

Adult↗
PubMed1999

Risk communication: clinicians' reported approaches and perceived values.

Despite significant conceptual and empirical advances in research on the risk assessment of violence during the last decade, there has apparently been no empirical research in the related area of risk communication. After summarizing the major theoretical and practical justifications for studying risk communication, this article describes the results of two studies of clinicians' risk communication practices. In Study 1, practicing clinicians (psychiatrists and psychologists; n = 55) were surveyed. Only one clinician indicated that he employed numerical probability figures in communicating risk; a total of nine reasons for not using numerical probabilities were cited, in varying combinations, by participants. Risk communication practices that were reportedly employed included a total of 11 approaches, endorsed in varying combinations. In Study 2, a separate sample of clinicians (n = 59) rated (1) the importance of the Study 1 reasons against using numerical probability figures in risk communication and (2) the value of the different forms of risk communication derived in Study 1. These data apparently offer the first empirical description of how clinicians communicate the results of risk assessments of violence and their reasons for communicating in such ways.

Communication↗
PubMed1998

Crystal structures of HIV-1 reverse transcriptase in complex with carboxanilide derivatives.

The carboxanilides are nonnucleoside inhibitors (NNIs) of HIV-1 reverse transcriptase (RT), of potential clinical importance. The compounds differ in potency and in their retention of potency in the face of drug resistance mutations. Whereas UC-84, the prototype compound, only weakly inhibits many RTs bearing single point resistance mutations, inhibition by UC-781 is little affected. It has been proposed that UC-38 and UC-781 may form quaternary complexes with RT at a site other than the known binding pocket of other NNIs. X-ray crystal structures of four HIV-1 RT-carboxanilide complexes (UC-10, UC-38, UC-84, and UC-781) reported here reveal that all four inhibitors bind in the usual NNI site, forming binary 1:1 complexes with RT in the absence of substrates with the amide/thioamide bond in cis conformations. For all four complexes the anilide rings of the inhibitors overlap aromatic rings of many other NNIs bound to RT. In contrast, the second rings of UC-10, UC-84, and UC-781 do not bind in equivalent positions to those of other "two-ring" NNIs such as alpha-APA or HEPT derivatives. The binding modes most closely resemble that of the structurally dissimilar NNI, Cl-TIBO, with a common hydrogen bond between each carboxanilide NH- group and the main-chain carbonyl oxygen of Lys101. The binding modes differ slightly between the UC-10/UC-781 and UC-38/UC-84 pairs of compounds, apparently related to the shorter isopropylmethanoyl substituents of the anilide rings of UC-38/UC-84, which draws these rings closer to residues Tyr181 and Tyr188. This in turn explains the differences in the effect of mutated residues on the binding of these compounds.

Anilides↗
PubMed1998

Time in hospital.

This article is based on research into patients' perceptions of being in hospital. Time, ordinarily taken for granted, becomes a significant problem for people in hospital. Patients seek control over time that they do not seem to have during their stay in hospital. They try to keep track of time and find ways of passing it, while believing that precious personal time is lost to them. The insight gained into differing perceptions of time and how patients coped with these can be used to reduce some of the tensions and negative aspects of the way time is experienced in hospital.

Adaptation, Psychological↗