Search PubMed⌕ Search

Biomedical subjects

D J Jones

Publications and source records attributed to D J Jones.

At least 19 recordsLinked to original sources
PubMed2005

The effects of chemical or surgical deafferentation on [3H]-acetylcholine release from rat spinal cord.

Cholinergic modulation of nociceptive transmission through both nicotinic and muscarinic receptors in the spinal cord represents an important mechanism in pain signaling. However, what neuronal elements release acetylcholine and how release might change in response to deafferentation are unclear. The present studies demonstrated Ca++- and K+-dependent release of [3H]-acetylcholine from slices of regional areas of rat spinal cord. That [3H]-acetylcholine was synthesized from [3H]-choline was demonstrated by the lack of [3H]-acetylcholine release following incubation with either the choline uptake inhibitor hemicholinium or the choline acetyltransferase inhibitor bromoacetylcholine. Rats treated neonatally with capsaicin or with spinal nerve ligation as adults showed a significantly decreased K+-stimulated release of [3H]-acetylcholine from dorsal horn but not ventral horn lumbar spinal cord slices. In rats subjected to dorsal rhizotomy, while basal release from lumbar dorsal spinal cord slices was reduced, K+-stimulated [3H]-acetylcholine release, while decreased, was not significantly different compared with controls. The data presented here show that there are regional differences in the release of acetylcholine from spinal cord and that this release can be modulated by chemical or surgical deafferentation. These results also indicate that the source of acetylcholine in the dorsal cord originates mainly from resident somata and their collaterals, interneurons and/or descending terminals, with only very minor contributions coming from primary afferents. The present data help to further elucidate the role of acetylcholine in spinal signaling, particularly with respect to the effects of nerve injury and nociceptive neurotransmission.

Acetylcholine↗
PubMed2005

The effects of ractopamine hydrochloride on lean carcass yields and pork quality characteristics.

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P < 0.05) with increasing dietary concentrations of RAC, but feed intake did not differ (P > 0.05). Dressing percentage was higher (P < 0.05) for RAC-treated pigs. Subjective color, firmness, marbling scores, and Minolta L* reflection of the LM were not different (P > 0.05) among treatments. Carcass weights were heavier (P < 0.05) for pigs treated with RAC compared with control pigs and were higher for R20 than for R10. The RAC-fed pigs had greater (P < 0.05) yields (actual and percentage of HCW) of the following Institutional Meat Purchase Specification (IMPS) cuts than control pigs: trimmed, boneless ham (IMPS-402C and IMPS-402G), loin (IMPS-414), sirloin, and Boston butt (IMPS-406A). Pigs treated with RAC had a greater (P < 0.05) percentage of fat-free lean trimmings (IMPS-418) than did control pigs. Pigs treated with the R20 concentration had increased (P < 0.05) water-holding capacity compared with control pigs. Purge loss decreased linearly (P < 0.05) with increasing RAC compared with control for 14-d aged, non-enhanced loins. Warner-Bratzler shear (WBS) force values measured for nonenhanced chops were greater for RAC-treated pigs than for control pigs with a low dose response (P = 0.001). Enhanced chop (salt and phosphate injection) WBS values did not differ (P > 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor.

Adrenergic beta-Agonists↗
PubMed2004

Experimental implementation of optical clockwork without carrier-envelope phase control.

We demonstrate optical clockwork without the need for carrier-envelope phase control by use of sum-frequency generation between a continuous-wave optical parametric oscillator at 3.39 microm and a femtosecond mode-locked Ti:sapphire laser with two strong spectral peaks at 834 and 670 nm, a spectral difference matched by the 3.39-microm radiation.

Journal Article↗
PubMed2004

Carrier-envelope phase-controlled quantum interference of injected photocurrents in semiconductors.

We demonstrate quantum interference control of injected photocurrents in a semiconductor using the phase stabilized pulse train from a mode-locked Ti:sapphire laser. Measurement of the comb offset frequency via this technique results in a signal-to-noise ratio of 40 dB (10 Hz resolution bandwidth), enabling solid-state detection of carrier-envelope phase shifts of a Ti:sapphire oscillator.

Journal Article↗
PubMed2003

Adsorption of a cationic gemini surfactant from aqueous solution onto aluminosilicate powders of the MCM-41 type: effect of pore size and co-adsorption of phenol.

The adsorption of cationic gemini dodecanediyl-alpha,omega-bis(dodecyldimethylammonium) bromide (i.e., C12C12C12) from aqueous solution onto aluminosilicate powders of the MCM-41 type (referred to as SiAl32dx, where x is the mean pore diameter in A) has been studied at 298 K under the conditions of free pH of the aqueous phase. Macroporous silica gel XO15M was used for comparative purposes. The discussion was based on the interpretation of experimental adsorption isotherms and differential enthalpies of displacement obtained on various solid samples. For the hydrogen-exchanged SiAl32d28 sample (i.e., H+-SiAl32d28), the adsorption of bromide counterions Br- at the solid-solution interface, the isotherm of the pH evolution in the equilibrated supernatant liquid, and the electrophoretic mobility of the solid particles coated with the adsorbed C12C12C12 were additionally measured. The uptake of phenol (PhOH) by a surfactant-solid system from a 1.5 mmolkg(-1) PhOH solution and the related thermal effect of displacement onto SiAl32d50 were quantified with the use of the solution depletion technique combined with UV spectrophotometry and the titration calorimetry technique. Titration calorimetry was also used to determine the molar enthalpy change accompanying micellization of C12C12C12 in pure deionized water and in a 1.5 mmolkg(-1) PhOH solution at 298 K. The adsorption of C12C12C12 occurs simultaneously on the external surface and on the pore walls and it is a strongly co-operative phenomenon. Surfactant aggregates forming at adsorption saturation are thought to be composed of the adsorbed surfactant units having their cationic head groups mostly oriented outward with respect to the solid surface. Therefore, they can provide co-adsorption sites for polarisable phenol molecules. On average, there is one phenol molecule retained for one gemini cation adsorbed. Transfer of phenol from the aqueous phase to either the bulk micelles or to the interfacial aggregates is enthalpically favourable.

Journal Article↗
PubMed2002

The influence of histological diagnosis on the postoperative complication rate following trans-urethral resection of prostate (TURP).

BACKGROUND: A number of studies have shown that the early mortality following TURP is higher for patients with prostate cancer than those with benign disease. This study examines the effect of the histological diagnosis on the predischarge complication rate following TURP. METHODS: Information on the postoperative, predischarge complications of 3036 patients, who underwent TURP over the last decade at our institution, was collated from the urology department database (AuditBase for Windows). The information on this database is collected prospectively, at the point of care and validated at monthly audit meetings. Statistical analyses were performed using chi2 and difference of proportion where n > 60. Statistical significance was taken as P < 0.05. RESULTS: The postoperative, predischarge major complication rate for patients with benign disease was 2.1%. This was not statistically different from the 2.3% complication rate seen in patients with malignant disease. Patients suffering a postoperative complication stayed in hospital significantly longer than those who had a straightforward postoperative course (P < 0.001); however, patients with malignant histology suffering a postoperative complication did not stay statistically significantly longer than those with benign histology suffering a postoperative complication (P < 0.1). CONCLUSIONS: Patients undergoing TURP for prostate cancer do not suffer more postoperative, predischarge complications or stay in hospital longer than patients undergoing TURP for benign disease.

Aged↗
PubMed2001

Characterization of metabolites of the chemopreventive agent curcumin in human and rat hepatocytes and in the rat in vivo, and evaluation of their ability to inhibit phorbol ester-induced prostaglandin E2 production.

Curcumin, the yellow pigment in turmeric, has been shown to prevent malignancies in a variety of tissues in rodents, especially in the intestinal tract. Pharmacological activities of curcumin in cells in situ germane to chemoprevention, such as inhibition of expression of cyclooxygenase-2 (COX-2), require drug concentrations in the 10(-5) - 10(-4) M range. The systemic bioavailability of curcumin is low, so that its pharmacological activity may be mediated, in part, by curcumin metabolites. To investigate this possibility, we compared curcumin metabolism in human and rat hepatocytes in suspension with that in rats in vivo. Analysis by high-performance liquid chromatography with detection at 420 and 280 nm permitted characterization of metabolites with both intact diferoylmethane structure and increased saturation of the heptatrienone chain. Chromatographic inferences were corroborated by mass spectrometry. The major metabolites in suspensions of human or rat hepatocytes were identified as hexahydrocurcumin and hexahydrocurcuminol. In rats, in vivo, curcumin administered i.v. (40 mg/kg) disappeared from the plasma within 1 h of dosing. After p.o. administration (500 mg/kg), parent drug was present in plasma at levels near the detection limit. The major products of curcumin biotransformation identified in rat plasma were curcumin glucuronide and curcumin sulfate whereas hexahydrocurcumin, hexahydrocurcuminol, and hexahydrocurcumin glucuronide were present in small amounts. To test the hypothesis that curcumin metabolites resemble their progenitor in that they can inhibit COX-2 expression, curcumin and four of its metabolites at a concentration of 20 microM were compared in terms of their ability to inhibit phorbol ester-induced prostaglandin E2 (PGE2) production in human colonic epithelial cells. Curcumin reduced PGE2 levels to preinduction levels, whereas tetrahydrocurcumin, previously shown to be a murine metabolite of curcumin, hexahydrocurcumin, and curcumin sulfate, had only weak PGE2 inhibitory activity, and hexahydrocurcuminol was inactive. The results suggest that (a) the major products of curcumin biotransformation by hepatocytes occur only at low abundance in rat plasma after curcumin administration; and (b) metabolism of curcumin by reduction or conjugation generates species with reduced ability to inhibit COX-2 expression. Because the gastrointestinal tract seems to be exposed more prominently to unmetabolized curcumin than any other tissue, the results support the clinical evaluation of curcumin as a colorectal cancer chemopreventive agent.

Adult↗
PubMed2001

HIV infection and depressive symptoms: an investigation of African American single mothers.

Risk for depressive symptoms among HIV-infected African American single mothers (n = 96), relative to demographically matched non-infected single mothers (n = 120), was examined, using both self-report and clinician-rated scales of depression. Assessment of depressive symptoms occurred at two points separated by one year. Findings revealed that HIV-infected mothers were at greater risk for depressive symptoms at both assessments, regardless of method of assessment. Moreover, HIV-infected mothers remained at greater risk when analyses were limited to cognitive and affective symptoms of depression, decreasing the likelihood that the difference between the two groups was due to greater endorsement of somatic symptoms of depression by the HIV-infected group.

Adult↗
PubMed2001

Disease status in African American single mothers with HIV: the role of depressive symptoms.

The association between depressive symptoms and 2 measures of HIV disease status in 73 African American single mothers was examined. Hierarchical multiple regression analyses revealed that clinician-rated depressive symptoms predicted subjective, but not objective, parameters of disease status 12 to 14 months later. More symptoms of depression at the 1st assessment predicted an increase in physical complaints over the course of the study. Results suggest that researchers and clinicians interested in enhancing quality of life among African American single mothers with HIV infection, an understudied population within the HIV-AIDS literature, should consider both subjective and objective measures of the disease.

Adult↗
PubMed2000

SFC/FTIR, SFC/APCI-MS and MALDI-TOF-MS for the analysis of siloxane-ethylene oxide copolymers.

Polydimethylsiloxanes (PDMSs) modified by introducing ethylene oxide units with the aim of forming sufficiently water-soluble siloxane compounds were characterized using supercritical fluid chromatography (SFC) coupled with Fourier transform infrared (FTIR) spectroscopy and atmospheric pressure chemical ionization mass spectrometry (APCI-MS), and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS). SFC has a domain in analyzing oligomers. Hyphenated techniques enable elucidation of the components. Remarkable is the resolution and short analysis time of MALDI-TOF-MS. SFC also allows quantification of the basic and reaction products.

Chromatography↗
PubMed2000

Endogenous lipid pneumonia in cats: 24 cases (1985-1998).

OBJECTIVE: To determine clinical signs, radiographic and histologic abnormalities, and concurrent diseases in cats with endogenous lipid pneumonia (EnLP) and to determine the pathologic importance of EnLP in cats. DESIGN: Retrospective study. ANIMALS: 24 cats. PROCEDURE: Medical records of cats in which EnLP was confirmed by histologic examination of necropsy specimens were reviewed. Information collected from the medical records included signalment, body weight, clinical signs, and results of clinicopathologic tests. Thoracic radiographs were reviewed by a radiologist; histologic specimens were reviewed by a pathologist. RESULTS: All cats had nonspecific clinical abnormalities, such as lethargy, anorexia, or weight loss; 16 had signs of respiratory tract disease. All cats had concurrent systemic diseases, and clinicopathologic abnormalities were reflective of these conditions. Nonspecific abnormalities were detected on thoracic radiographs from 9 of 11 cats. Most cats had macroscopic, multifocal, subpleural lesions; inflammatory infiltrates, cholesterol clefts, and multinucleated giant cells were common. Ten cats had an underlying obstructive pulmonary disease that was the likely cause of EnLP. Lesions of EnLP were not considered to be severe enough or extensive enough to be the cause of death in any of these cats. CONCLUSIONS AND CLINICAL RELEVANCE: EnLP is an uncommon respiratory tract disorder of cats with no pathognomonic clinical, laboratory, or radiographic findings. Although EnLP was not the cause of death in any of these cats, results of the present study do suggest that EnLP may be a marker for potentially severe underlying obstructive pulmonary disease.

Animals↗
PubMed2000

Surveillance for bladder cancer: the management of 4.8 million people. South-west Urologists.

OBJECTIVE: To document the workload of bladder cancer surveillance on the British urologist. Methods Thirty-one consultant urologists serving a population of 4.8 million were sent postal questionnaires eliciting their views on the management of superficial bladder cancer. The number, type and outcome of cystoscopies performed over a 6-week period throughout the region was then assessed prospectively. Results One person in 1450 in the South-west region is undergoing follow-up for bladder cancer. Of the responding consultants, 36% would give a single dose of intravesical chemotherapy within 24 h of resection for a G1/2 pTa tumour and 84% would perform the first check cystoscopy at 3-4 months. Over the 6-week period of the study, 696 cystoscopies were performed; there was considerable variation among centres in the choice of cystoscopy type, with 3-80% being rigid cystoscopies. Overall, there was a positive finding in 31% of the assessments. CONCLUSION: This study documents the practice of a significant number of UK urologists in the management of superficial bladder cancer. There are considerable variations among individuals in the type and timing of check cystoscopy.

Cystoscopy↗
PubMed2000

Maternal and paternal parenting during adolescence: forecasting early adult psychosocial adjustment.

This study investigated the relationship of maternal and paternal parenting behavior (acceptance and firm control) during adolescence to four domains of early adult functioning (internalizing problems, externalizing problems, prosocial competence, and cognitive competence). Twenty-one females and 29 males from intact families, along with their mothers and fathers, participated. Assessments were conducted in adolescence and early adulthood, separated by approximately five and one-half years. Higher levels of maternal firm control during adolescence were associated with more secure early adult romantic attachment and lower levels of educational achievement. There were no main effects for fathers, but paternal parenting behavior interacted with maternal parenting behavior to predict both early adult romantic attachment and delinquency. Clinical implications and directions for future research are discussed.

Adaptation, Psychological↗
PubMed1999

An audit of positive findings in flexible and rigid check cystoscopy.

Both flexible and rigid cysto-urethroscopy are routinely used in the surveillance of transitional cell bladder tumours. This study addressed the issue of patient selection for either rigid or flexible cystoscopy. What proportion of positive findings at flexible cystoscopy and negative findings at rigid cystoscopy are acceptable? Standards were set of 10% for the former and 50% for the latter and our practice was then audited. A retrospective analysis of 800 patients undergoing check cystoscopy revealed a positive finding rate of 8.3% using the flexible instrument and 48.1% using the rigid instrument.

Carcinoma, Transitional Cell↗
PubMed1998

Breast masses in women treated for childhood cancer: incidence and screening guidelines.

BACKGROUND: The authors' aims were to define the frequency, characteristics, and methods of detection of breast masses in young women treated for childhood cancer and to develop screening guidelines for the growing population of long term survivors. METHODS: The authors reviewed medical records of all female patients treated for malignancy at a childhood cancer center over a 34-year period to identify those who developed a breast mass and to determine the cumulative incidence of breast cancer as a second primary cancer. RESULTS: A breast mass was identified in 66 patients who had been diagnosed with a malignancy at a median age of 13.8 years (range, 0.4-24.4 years). Masses were initially detected by breast self-detection in 32 and clinical examination in 28; the method of detection was unknown in 6 cases. Breast lesions were benign in 41 patients and malignant in 26; 1 patient had both a benign and a malignant lesion. Of the 26 malignant masses, 14 represented metastases of the primary malignancy and 12 were primary breast cancers as second primary cancers. The median interval to a primary breast cancer as a second primary cancer was 13.6 years (range, 9.2-24.4 years), and the median age at detection was 27.7 years (range, 12.5-43.1 years). The 25-year cumulative incidence of primary breast cancer as a second primary cancer in this cohort was 1.7% (95% CI, 0.4%-2.9%). This represented a 20-fold increase (95% CI, 10-36) over the expected incidence in age-matched and race-matched controls. CONCLUSIONS: Young women treated for childhood cancer have a significantly increased risk of breast cancer compared with age-matched controls. For this group of patients, the authors recommend patient education regarding this risk and the importance of properly conducted self-examination as the foundation of breast cancer screening. In addition, clinical and mammographic screening should be instituted at a younger age and performed more frequently than recommended for the general population of women.

Adolescent↗
PubMed1998

Pleasure and pain in doing well, together: an investigation of performance-related affect in close relationships.

In a series of four studies, the self-evaluation maintenance (SEM) model is used to predict peoples' self-reported affective responses to doing better or worse than their partners. Both self-protective reactions to comparison (i.e., those predicted by the original SEM model) and empathic reactions to the partner's response (i.e., those predicted by the extended SEM model) were obtained. In addition, as predicted on the basis of both models, comparisons with romantic partners resulted in a different pattern of self-reported affect than did comparisons with strangers. Unexpectedly, it appeared that empathic effects were minimal or absent among dating partners when comparisons were in areas of high self-relevance.

Achievement↗