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Biomedical subjects

D L Wilkinson

Publications and source records attributed to D L Wilkinson.

13 recordsLinked to original sources
PubMed2005

The emergency department approach to violently injured patient care: a regional survey.

OBJECTIVE: Since the early 1990s public health workers have challenged healthcare practitioners to take an active role in violence prevention with patients aged 10-24 years. Emergency department (ED) clinicians are uniquely positioned to identify, assess, and refer youth involved in violent events. The objective of this study was to describe ED directors' estimate of the number of violently injured youth seen, the presence of established protocols or guidelines for handling youth violence, and the type of training programs offered to ED physicians regarding this issue. METHODS: The authors conducted a survey of EDs (n = 64) in the Philadelphia metropolitan region to determine the standard of ED care for violently injured youths. Half of the EDs were in urban areas and half in suburban. RESULTS: A total of 41 out of 64 (64.1%) ED directors completed and returned the written questionnaire. In addition to treating the specific injuries sustained, ED responses to youth violence primarily involved talking with patients about the events surrounding the injury. The estimated number of violently injured youth seen per month varied considerably. Twenty four directors (58.5%) estimated that their institution treated fewer than 10 per month; 10 (24.4%) reported 11-30, and seven (17.1%) mostly large urban hospitals, saw more than 30 per month. Although most hospitals reported that the staff counsels patients about safety concerns, only 17% offered their staff formal training programs on youth violence. CONCLUSIONS: To address the prevention of youth violence, EDs need specific training programs for ED staff, as well as systematic risk assessment and referral resources for structured intervention and follow up.

Adolescent↗
PubMed2001

Diverse heteroleptic ytterbium(III) thiocyanate complexes by oxidation from bis(thiocyanato)ytterbium(II).

The new ytterbium(II) thiocyanate complex [Yb(NCS)2(thf)2] (1), synthesised by redox transmetallation between [Hg(SCN)2] and ytterbium metal in THF at room temperature, gave monomeric, eight coordinate [Yb-(NCS)2(dme)3] (2, dme = 1,2-dimethoxyethane) on crystallisation from DME, and is a powerful, synthetically useful reductant. Thus, oxidation of 1 with Hg(SCN)2, Hg(C6F5)2/HOdpp (HOdpp = 2,6-diphenylphenol), TlCp (Cp = C5H5 or CH3C5H4), Tl(Ph2pz) (Ph2pz = 3,5-diphenylpyrazolate) and CCl3CCl3 in THF yielded the ytterbium(II) complexes [Yb(NCS)3(thf)4] (3), [Yb-(NCS)2(Odpp)(thf)3](4), [Yb(NCS)2Cp-(thf)3] (Cp = C5H5 (5), CH3C5H4 (6)), [Yb(NCS)2(Ph2pz)(thf)4] (7) and [Yb(NCS)2Cl(thf)4] (8). In the solid state, complexes 4, 6 and 7 were shown by X-ray crystallography to be six, eight and eight coordinate monomers, respectively. Exclusively terminal, N-bound transoid thiocyanate bonding is observed with eta1-Odpp (4), eta5/-C5H4Me (6) and eta2-Ph2Pz (7) ligands attached approximately perpendicular to the N...N vector. The chloride complex 8 is not a molecular species, but consists of discrete, seven coordinate [YbCl2(thf)5] cations and [Yb(NCS)4(thf)3] anions. By contrast, oxidation of 1 with TlO2CPh gave a mixture of [[Yb(NCS)-(O2CPh)2(thf)2]2] (9) and 3 through rearrangement of an initially formed [Yb(NCS)2(O2CPh)] species. The X-ray structure of 9 indicates a dimeric complex with a (Yb(mu-O2CPh)4Yb] core that contains both bridging bidentate and bridging tridentate benzoate groups, and with a terminal N-bound thiocyanate and two THF ligands on each ytterbium. Reduction of Ph2CO with 1 in THF yielded the dinuclear complex [[Yb(NCS)2(thf)3]2(mu-OC(Ph)2C(Ph)2O)] (10), in which two octahedral Yb centres are bridged by a 1,1,2,2-tetraphenylethane-1,2-diolate ligand, derived from reductive coupling of the benzophenone reagent.

Journal Article↗
PubMed2001

What we know about gun use among adolescents.

The current generation of American teenagers has grown up surrounded by gun violence. Guns have played a significant role in shaping the developmental trajectories and behaviors of many inner-city youths. In this essay, we examine the role of guns in the lives of young people, and especially in the social and symbolic construction of violent events among adolescents, primarily focusing on males. First, we review studies of gun attitudes and behaviors as well as several epidemiological studies of firearm experiences and risk factors for violence among youth. Second, we summarize several recent studies on the trends in youth violence in relation to firearms. Next, we review findings from our original research based on in-depth interviews with 377 active gun offenders from two socially isolated inner-city neighborhoods. We present descriptive counts for the sample on variables relating to gun acquisition and use. Data on the use of guns in violent events among adolescents are generally lacking in prior research. We attempt to fill that knowledge gap by presenting a summary of our more detailed analysis of gun and nongun use in violent events reported by our respondents.

Adolescent↗
PubMed1994

Polynuclear aromatic hydrocarbon contaminants in oysters from the Gulf of Mexico (1986-1990).

Polynuclear aromatic hydrocarbon (PAH) contaminant concentrations in 870 composite oyster samples from coastal and estuarine areas of the Gulf of Mexico analyzed as part of National Oceanographic and Atmospheric Administration's (NOAA's) National Status and Trends (NS&T) Mussel Watch Program exhibit a log-normal distribution. There are two major populations in the data. The cumulative frequency function was used to deconvolute the data distribution into two probability density functions and calculate summary statistics for each population. The first population consists of sites with lower PAH concentration probably due to background contamination (i.e. stormwater runoff, atmospheric deposition). The second population are sites with higher concentrations of PAHs associated with local point sources of PAH input (i.e. small oil spills, etc.). The temporal pattern for the mean concentration of the populations from the Gulf of Mexico is consistent with large-scale climatic factors such as the El Niño cycles which affect the precipitation regime.

Journal Article↗
PubMed1993

National status and trends mussel watch program: chlordane-related compounds in Gulf of Mexico oysters, 1986-1990.

The National Oceanic and Atmospheric Administration's National Status and Trends (NS&T) Program has been monitoring the chemical contamination in bivalve tissues from the US coastal waters since 1986. alpha-Chlordane, trans-nonachlor, heptachlor and heptachlor epoxide, components of technical chlordane, are among the chlorinated pesticides measured. The geographical distribution of these chlordane compounds in oyster samples from the US Gulf of Mexico is well-established. For example, highest residue levels, predominantly alpha-chlordane and trans-nonachlor, were encountered in samples collected near highly populated areas in contrast with the concentrations measured in predominantly agricultural areas. Data collected during 5 years of bivalve sampling are used to evaluate temporal trends in residue concentrations at most NS&T sites. Minor decreases can be observed in the concentrations of alpha-chlordane and trans-nonachlor. Heptachlor and its epoxide concentrations, in contrast, have been increasing since 1987.

Journal Article↗
PubMed1991

Ultrasonographic diagnosis of symptomatic deep venous thrombosis in pregnancy.

Color flow imaging combined with compression ultrasonography were used to prospectively evaluate symptomatic patients first seen with suspected deep vein thrombosis during pregnancy. The incidence of symptomatic deep vein thrombosis (7 of 10,000 deliveries) shown prospectively by ultrasonography was similar to that of historic controls who had a diagnosis confirmed by venography (11 of 26,191 deliveries). A preferential pattern of proximal left-sided iliac or femoral vein involvement was common to both cohorts, being seen in five of the seven cases diagnosed by ultrasonography and eight of the eleven cases diagnosed by venography. We conclude that ultrasonography, consisting of compression ultrasonography and color flow imaging, can replace venography in the diagnosis and evaluation of the extent of symptomatic deep vein thrombosis during pregnancy.

Adolescent↗
PubMed1991

Predicting the solubility of recombinant proteins in Escherichia coli.

We have studied the cause of inclusion body formation in Escherichia coli grown at 37 degrees C using statistical analysis of the composition of 81 proteins that do and do not form inclusion bodies. Six composition derived parameters were used. In declining order of their correlation with inclusion body formation, the parameters are charge average, turn forming residue fraction, cysteine fraction, proline fraction, hydrophilicity, and total number of residues. The correlation with inclusion body formation is strong for the first two parameters but weak for the last four. This correlation can be used to predict the probability that a protein will form inclusion bodies using only the protein's amino acid composition as the basis for the prediction.

Amino Acids↗
PubMed1986

Vagal involvement in the pressor responses to cranial artery infusions of bradykinin in anaesthetised greyhounds.

In anaesthetised greyhounds, vertebral and carotid artery infusions of bradykinin increased blood pressure whereas intravenous infusions caused a decrease. With each route of administration, heart rate and cardiac output increased while total peripheral resistance fell. With cranial artery infusions, the consecutive pretreatments of propranolol, phentolamine and vagal cooling resulted in a progressive reduction in the heart rate responses and conversion of the pressor to depressor responses. The responses to intravenous infusions of bradykinin were little changed. In contrast, when the initial pretreatment was interruption of vagal transmission, cranial artery infusions of bradykinin were at once depressor and the depressor response to intravenous infusions immediately enhanced. Subsequent propranolol and phentolamine were without further effect on the blood pressure responses although propranolol did reduce the tachycardia responses. It is concluded that while the tachycardia induced by cranial artery infusions of bradykinin has both cardiac sympathetic and vagal withdrawal components, the hypertensive action is mediated by an increase in cardiac output due largely to withdrawal of cardiac vagal tone.

Anesthesia↗
PubMed1986

The effect of naloxone on pressor responses to angiotensin II in anaesthetized greyhounds.

In greyhounds anaesthetized with morphine and chloralose, vertebral artery infusions of angiotensin II resulted in a similar pressor response but smaller tachycardia than in greyhounds anaesthetized with chloralose alone. The pressor responses to intravenous infusions of angiotensin II were significantly larger in the morphine premedicated greyhounds. In greyhounds anaesthetized with morphine and chloralose, pressor responses to vertebral artery angiotensin II were potentiated following the administration of naloxone via either a vertebral artery or intravenously although the effect was more consistent with the former route. No such effect was seen in greyhounds anaesthetized with chloralose alone. Naloxone had no effect on the pressor responses to intravenous angiotensin II or carotid artery occlusion. The heart rate responses to vertebral artery angiotensin II in greyhounds anaesthetized with morphine and chloralose were potentiated by naloxone such that they were not significantly different from the responses obtained in greyhounds anaesthetized with chloralose alone before naloxone. As was observed with the pressor responses, the potentiation was more apparent with the vertebral artery route of administration of naloxone. There was no potentiation of the heart rate responses in the chloralose group of greyhounds. It is suggested that morphine premedication may repress the vagal withdrawal mechanism while potentiating the sympathetic vasomotor mechanism mediating the central cardiovascular actions of angiotensin II.

Anesthesia, General↗
PubMed1985

Role of prostaglandins and the areas postrema in the central pressor action of bradykinin.

Vertebral and carotid artery infusions of bradykinin increased blood pressure and heart rate in anaesthetised greyhounds. Indomethacin pretreatment abolished the pressor response to vertebral infusion and reduced that to carotid infusion. Areas postrema ablation abolished the pressor response to bradykinin with both routes of administration. The tachycardia responses to cranial artery infusions and the entire cardiovascular response to intravenous infusion were unaffected by either treatment. It is concluded that intact areas postrema and normal prostaglandin synthesis are essential for the full expression of the central pressor action of bradykinin.

Angiotensin II↗
PubMedDate not supplied

Purification by immobilized metal affinity chromatography of human atrial natriuretic peptide expressed in a novel thioredoxin fusion protein.

A fusion protein that contains human atrial natriuretic peptide (ANP) at its carboxy terminus has been genetically engineered with the objective of being able to produce the peptide in a process with a relatively simple purification procedure. The fusion protein also includes a (His)6 metal affinity binding site at the amino terminus, followed by Escherichia coli thioredoxin, a factor Xa protease recognition site, and ANP. With induction of the tac promoter at 30 degrees C, the expression level of the fusion protein was high (10% of total cell protein as measured by densitometry) and it was almost completely (92%) expressed as a soluble protein in the cytoplasm. A step gradient elution with imidazole of a column of Ni2+ chelated to iminodiacetic acid-agarose saturated with proteins in crude cell extract gave a very nearly pure fusion protein. After digestion of the purified fusion protein with factor Xa protease, ANP of exactly the correct size (to within 2 Da) was observed by coupled HPLC/mass spectrometry.

Amino Acid Sequence↗