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Biomedical subjects

R D Jones

Publications and source records attributed to R D Jones.

At least 37 records · Page 2Linked to original sources
PubMed2002

Testosterone acts as a coronary vasodilator by a calcium antagonistic action.

T acts as a vasodilator in vitro and in vivo. Supplemental T therapy in humans with angina improves symptoms and reduces objective measures of ischemia. In left anterior descending coronary arteries taken from adult male Wistar rats, T abolishes 100+/-4.2% of calcium-dependent contraction induced by potassium chloride, 82.3+/-6.1% of the mostly calcium-dependent contraction induced by prostaglandin-F-2-alpha, but only 45.3+/-3.4% of the contraction induced by phorbol-12,13-dibutyrate (PDBu) in the presence of extracellular calcium, and 54.5+/-4.5% of the contraction induced by PDBu in the absence of extracellular calcium. These findings suggest that T is primarily inhibiting the calcium-dependent elements of vascular contraction.

Animals↗
PubMed2002

Saccade sequences as markers for cerebral dysfunction following mild closed head injury.

Diffuse axonal injury caused by mild closed head injury (CHI) is likely to affect the neural networks concerned with the planning and execution of sequences of memory-guided saccades. Thirty subjects with mild CHI and thirty controls were tested on 2- and 3-step sequences of memory-guided saccades. CHI subjects showed more directional errors, larger position errors, and hypermetria of primary saccades and final eye position. No deficits were seen in temporal accuracy (timing and rhythm). These results suggest that computerized tests of saccade sequences can provide sensitive markers of cerebral dysfunction after mild CHI.

Adolescent↗
PubMed2001

In situ reverse transcription to detect the cbbL gene and visualize RuBisCO in chemoautotrophic nitrifying bacteria.

AIMS: In situ methodologies targeting the cbbL gene were used to visualize cells of nitrifying bacteria. Both procaryotic in situ PCR (IS-PCR) and in situ reverse transcription (ISRT) protocols were employed to determine gene presence and expression, respectively. METHODS AND RESULTS: Aged-oligotropic seawater samples were inoculated with microbial assemblages containing a mixture of actively growing nitrifying bacteria, starved nitrifying bacteria, and heterotrophic bacteria without cbbL. After the molecular manipulations, we found that while all the nitrifiers (healthy or starved) with the cbbL gene were detected by IS-PCR, only the actively growing autotrophic nitrifiers with detectable levels of carbon fixation and nitrification activity were detected by ISRT analysis. CONCLUSION: These results show how IS-PCR and ISRT supplement each other, and their potential for the analysis of heterogeneous populations where an assortment of healthy and starved/dormant cells are expected.

Bacterial Proteins↗
PubMed2001

Gender differences in the vasomotor effects of different steroid hormones in rat pulmonary and coronary arteries.

It is well recognised that oestrogens possess vasodilatory properties, and similar responses to testosterone have been demonstrated. However, vasomotor effects of other steroid hormones have not been well described. Direct comparisons of the relative vasoactivity of different steroid hormones in different vascular beds in male and female genders have not been made. Coronary and pulmonary arteries from adult Wistar rats were mounted in a wire myograph, loaded to 100 and 17 mmHg respectively, maximally pre-contracted with 1 x 10(-4) M prostaglandin-F-2-alpha, and dose response curves to 1 x 10(-6) to 1 x 10(-3) or 3 x 10(-3) M of 17 beta-oestradiol, testosterone, progesterone, and cortisol dissolved in water were constructed. Addition of each steroid hormone caused acute, dose dependent dilatation in coronary and pulmonary vessels. In coronary arteries the order of activity was testosterone > progesterone > 17 beta-oestradiol > cortisol, p < 0.001. In pulmonary arteries, the order of activity was progesterone > testosterone > cortisol > 17 beta-oestradiol, p < 0.001. Pulmonary arteries from male animals were more sensitive to the effects of testosterone than those from female animals, p = 0.003, whereas coronary arteries from female animals were more sensitive to the effects of 17 beta-oestradiol than those from male animals, p < 0.001. We have demonstrated significant differences in the in vitro vasomotor effects of different steroid hormones in two distinct vascular beds. Gender differences in vasomotor responses to steroid hormones may play a role in the aetiology of vasospastic diseases.

Animals↗
PubMed2001

Severe developmental prosopagnosia in a child with superior intellect.

Developmental prosopagnosia, a lifelong inability to learn and recognize familiar faces, has rarely been reported, and there are even fewer cases that have been studied during childhood. Of the cases studied during childhood, significant "apperceptive" features to the face recognition defect have been noted. We had an opportunity to conduct extensive standard and experimental neuropsychological, psychophysiological, and neuroanatomical studies in a five-year-old child with severe developmental prosopagnosia. The subject was intellectually gifted (FSIQ = 130), but had a marked discrepancy between verbal and nonverbal abilities (VIQ = 140, PIQ = 110). Although some visual perceptual weaknesses were apparent, the subject's face recognition defect was found to cnform most closely to the "associative" type, and he did not have visual recognition deficits for any categories of nonunique entities. A novel finding was that the child's covert recognition of familiar faces based on an autonomic index was normal, suggesting that as in some adult-onset cases, the brain is capable of acquiring some information about familiar faces, even without conscious recognition. The child also had normal judgments of facial emotional expressions. Our report extends the understanding of the neuropsychological features of developmental prosopagnosia, and may help narrow the search for neuroanatomical correlates of this condition, which have yet to be identified.

Child, Preschool↗
PubMed2001

Dysfluency and involuntary movements: a new look at developmental stuttering.

Studies using modern imaging techniques suggest that, in developmental stuttering, there is dysfunction within the cortical and subcortical areas of the motor control system wider than that pertaining to speech motor control alone. If this is the case, one might expect motor deficits extending beyond and unrelated to the production of speech in people who stutter. This study explored this proposal by investigating the presence and characteristics of involuntary movements accompanying stuttering. Sixteen adults with developmental stuttering and 16 controls matched for age and sex were audio-videotaped during 5 minutes of conversational speech and reading a passage of 350 words. Audio-data were examined for dysfluencies. Movements of the face, head and upper body considered involuntary and not part of normal facial expression or gesture and not part of the mechanics of speech were identified and described from muted video-data. Subjects who stuttered had a higher proportion of classic (within-word) dysfluencies accompanied by involuntary movements (IMs) than controls during speech (24.4% vs. 4.5%, p = .054) and reading (28.6% vs. 4.9%, p = .033). There was no difference in proportion of classic dysfluencies accompanied by IMs between speech and reading for either group. IMs were also seen in both groups during fluent speech, with a similar incidence during free speech (3.9% vs. 3.0%, NS) but a greater incidence in the subjects who stuttered during reading (2.4% vs. 0.8%, p = .03). In contrast, there was no difference between the two groups for IMs accompanying normal (between-word) dysfluencies. This suggests that classic and normal dysfluency and their accompanying IMs have different etiologies. The notion that stuttering and IMs are due to altered function in a motor control system wider than that of speech motor control alone is supported by a higher incidence of IMs in people who stutter during both classic dysfluencies and fluent speech.

Adolescent↗
PubMed2001

Depression and anxiety in oncology: the oncologist's perspective.

Depression and anxiety frequently occur in oncology patients and have a significant impact on patient quality of life, health care utilization, and even disease outcome. Depression and anxiety are eminently treatable, and therefore psychiatric assessment and appropriate intervention should form an integral component of management strategy in patients with cancer. It is essential that patients are recognized at an early stage, so that resources can be targeted effectively at those most at risk of developing psychiatric morbidity. Evaluation techniques that can identify signs or symptoms of depression and anxiety and can be incorporated into the program of a busy oncology clinic or in the primary care setting are therefore needed. Diagnosis of depression and anxiety may be facilitated by using primary screening tools, such as the Hospital Anxiety and Depression Scale questionnaire, and by considering factors such as family psychiatric history, levels of family support, and degrees of pain suffered by the patient. In this article, the issues surrounding diagnosis of depression and anxiety in cancer patients and the benefits of early intervention are considered from the point of view of the oncologist.

Anxiety Disorders↗
PubMed2000

NADPH oxidase: a universal oxygen sensor?

NADPH oxidase is classically regarded as a key enzyme of neutrophils, where it is involved in the pathogenic production of reactive oxygen species. However, NADPH oxidase-like enzymes have recently been identified in non-neutrophil cells, supporting a separate role for NADPH-oxidase derived oxygen species in oxygen sensitive processes. This article reviews the current literature surrounding the potential role of NADPH oxidase in the oxygen sensing processes which underlie hypoxic pulmonary vasoconstriction, systemic vascular smooth muscle proliferation, carotid and airways chemoreceptor activation, erythropoietin gene expression, and oxytropic responses of plant cells.

Animals↗
PubMed2000

The effect of the nitric oxide synthase inhibitor N-gamma-nitro-L-argine methyl ester on hypoxic pulmonary vasoconstriction.

We studied the role of nitric oxide in the regulation of pulmonary arterial tone and hypoxic pulmonary vasoconstriction. Rat pulmonary arteries (n=65, diameter=440+/-12 microm) were loaded to 17.5 mm Hg in a wire myograph and incubated with the nitric oxide synthase inhibitor N-gamma-nitro-L-argine methyl ester (L-NAME; 1, 10 or 100 microM) or distilled water (50 microl) prior to preconstriction with either 100 microM prostaglandin F(2 alpha) followed by acetylcholine (0.1-100 microM) or 5 microM prostaglandin F(2 alpha) followed by hypoxia. Concentrations of L-NAME (10 and 100 microM) which attenuated acetylcholine dilatation, elevated basal tone from 0. 2+/-0.5% to 9.4+/-2.1% (P<0.01) and 18.3+/-3.2% (P<0.001), respectively, potentiated contraction to 5 microM prostaglandin F(2 alpha) from 35.9+/-3.1% to 56.2+/-6.8% (P<0.05) and 66.4+/-5.8% (P<0.001), respectively, but had no significant effect on hypoxic pulmonary vasoconstriction. This suggests basal pulmonary nitric oxide release occurs, as well as in response to agonist-induced contraction, but not hypoxic pulmonary vasoconstriction.

Animals↗
PubMed2000

Gas chromatographic determination of organomercury following aqueous derivatization with sodium tetraethylborate and sodium tetraphenylborate. Comparative study of gas chromatography coupled with atomic fluorescence spectrometry, atomic emission spectrometry and mass spectrometry.

Several hyphenated analytical techniques, including gas chromatography (GC) coupled with atomic fluorescence spectrometry (AFS), microwave-induced plasma atomic emission spectrometry (AES), and mass spectrometry (MS), have been evaluated for methylmercury and ethylmercury analysis following aqueous derivatization with both sodium tetraethylborate and sodium tetraphenylborate. Both GC-AFS and GC-AES were shown to be excellent techniques with detection limits in the range of sub-picogram levels (0.02-0.04 pg as Hg). Both techniques have wide linear ranges, although setting of the AFS sensitivity has to be selected manually based on the concentration of mercury in the sample. Phenylation seems to be more favorable in this study because of its capability of distinguishing between ethylmercury and inorganic mercury, and low cost compared to ethylation. Although sensitivity of GC-MS is poor with detection limits ranging from 30 to 50 pg as Hg, it is an essential technique for confirmation of the derivatization products.

Borates↗
PubMed2000

Capture ELISA and flow cytometry methods for toxicologic assessment following immunization and cyclophosphamide challenges in beagles.

The purpose of this subacute 22-day study was to evaluate methods for canine circulating immunoglobulins (IgM, IgG, and IgE) and select B- and T-lymphocyte populations (CD4-helpers, CD8-suppressors, pan-T and pan-B) for immunotoxicity testing using an organ system (concordance) approach. The challenge substance for immunoglobulin testing was repeated immunization with six-way distemper vaccination (DHLAPP), while the challenge substance for leukocyte subpopulations was treatment with cyclophosphamide. Immunoglobulin measurements were made by capture enzyme-linked immunosorbent assay (ELISA), and leukocyte immunophenotyping by fluorescein isothiocyanate/phycoerythrin conjugation (flow cytometry). A battery of parameters that would be used in a typical regulatory study were taken to aid interpretation of the data generated by these methods. Body weights, food consumption, clinical observations, complete clinical chemistry and urinalysis measurements were taken. Gross pathology and micropathology of sternal bone marrow, spleen, mesenteric and retropharyngeal lymph nodes, thymus, liver and kidney were completed. The ELISA method demonstrated acceptable intra-assay reproducibility for IgM, IgG and IgE, with values in good agreement as reported for radial immunodiffusion. The immunologic challenge demonstrated a biological trend of an increase in IgM that preceded an increase in IgG with no discernible trend in IgE response, and no abnormalities in lymphocyte subpopulations. Principle flow cytometry findings related to cyclophosphamide were that the relative percent of B cells decreased dramatically and progressively after compound administration; being statistically decreased in males on day 22 compared with day -5. The relative percent CD4 and CD8 contribution increased, but the CD4/CD8 ratio remained relatively unchanged as total white blood cells decreased progressively. The increase in relative percent CD4 (males only) was statistically significant according to a two-sample t-test on days 17, 20 and 22 when compared with the pre-treatment day -5. There was a relative percent increase in CD5-panT, but absolute numbers were dramatically decreased. We conclude that an organ system approach to assessment of the immune system which incorporates humoral antibody, enumeration of lymphocyte populations and pathologic evaluation of the lymphoreticular organs assists in the interpretation of an adverse toxicological response. The ELISA method for measurement of Igs detected the expected levels of IgG, IgM and IgE due to repeated vaccinations and to cyclophosphamide treatment. The flow cytometry method was acceptable for measuring select canine lymphocyte populations and detecting the expected decrease in B cells due to cyclophosphamide treatment. Both methods may be added to a testing battery for assessing immunotoxicityl in canine regulatory studies.

Adenoviridae↗
PubMed2000

The effect on sound generation of varying both gas flow rate and the viscosity of sputum-like gel in a simple tubular model.

Gas flows of 2, 3, and 4 L/min were directed through a sputum-like gel with viscosities of 100, 150, and 200 P and placed in a tube similar in diameter to a human segmental bronchus (4 mm), which was immersed in a bath of water. The sound produced by gas flow through the gel was recorded with a hydrophone. Sound data were subjected to time-expanded waveforms and fast Fourier transform (FFT) analysis. This study demonstrated that the number of crackles generated was directly related to the flow rate and inversely related to gel viscosity. The initial deflection width (IDW), two-cycle duration (2 CD), and peak-to-peak amplitude of crackles were significantly affected by the gas flow rate but not the viscosity of the gel. A lower gas flow rate generated crackles with longer IDW and 2 CD, but higher gas flow rates generated crackles with higher amplitude. Peak sound intensity measured from FFT increased as flow rate increased but decreased as the viscosity of the gel increased. At low gas flows, no gel-induced crackle sound was generated within the data capture window when the most viscous gel was examined. A digital video image of gas flow through the gel was captured, and this confirmed the absence of bubbles or slug formation at low flows through 200 P gel during the 3 seconds of data acquisition. This study describes some characteristics of crackles generated from different combinations of gas flow and gel viscosity and suggests that "coarse crackles" results from the explosion of gas bubbles in pulmonary secretions. Health care practitioners should consider the combined effect of rate of inspiratory gas flow and sputum viscosity during auscultation of patients' lungs.

Bronchi↗
PubMed2000

Moisturizing alcohol hand gels for surgical hand preparation.

With the use of novel formulary technology, unique moisturizing hand gels have been developed that offer significant advantages in perioperative and other health care settings. These advantages include the time-saving capabilities of a waterless formulation, the persistence and effectiveness of a surgical scrub, and the moisturization and protective properties of a lotion. Extensive laboratory and clinical studies, involving in vivo antimicrobial activity against resident and transient flora, skin moisturization on normal and dry skin, and compatibility with latex gloves, have supported these advantages. Nondrying alcohol hand gels can be used for antiseptic hand washing, hand scrubs between procedures (i.e., reentry scrubs), brushless surgical scrubs, moisturizers, and glove-donning aids.

Antisepsis↗
PubMed2000

Suppression of displacement in severely slowed saccades.

Severely slowed saccades in Spinocerebellar ataxia have previously been shown to be at least partially closed-loop in nature, their long duration means that they can be modified in-flight in response to intrasaccadic target movements. In this study, a woman with these pathologically slowed saccades could modify them in-flight in response to target movements, even when saccadic suppression of displacement (SSD) prevented conscious awareness of those movements. Thus, SSD is not complete, in that it provides perceptual information that is sub-threshold to consciousness but which can still be effectively utilised by the oculomotor system.

Adolescent↗
PubMed2000

Hydrogen peroxide--an intracellular signal in the pulmonary circulation: involvement in hypoxic pulmonary vasoconstriction.

Hypoxic pulmonary vasoconstriction (HPV) is a regulatory feature of the pulmonary circulation that ensures consistent matching of perfusion to ventilation in the normal lung. However, under pathophysiological conditions, HPV contributes to the elevated pulmonary arterial pressure inherent to numerous disease states. Consequently, control of HPV is an avenue of potential therapy for such conditions. This review discusses the role of hydrogen peroxide (H(2)O(2)) as an intracellular signal in the pulmonary circulation, concentrating on the potential involvement of H(2)O(2) in HPV and in the control of pulmonary arterial tone. Sites of hypoxic pulmonary arterial H(2)O(2) production include the mitochondrial electron transport chain, a microsomal electron transport chain containing an NADH oxidoreductase and alternatively, a membrane-bound NADPH oxidase. Each of these sources of H(2)O(2) and the effect of hypoxia on the production of reactive oxygen species are considered. The review also discusses the variance in vascular reactivity of H(2)O(2), which is described to elicit both pulmonary arterial vasoconstriction and dilatation at varying concentrations. The redox capabilities of H(2)O(2) are also considered. The relevance of all of these actions of H(2)O(2) are also assessed as potential pharmacological targets for the future development of therapy for lung diseases that are characterised by some degree of HPV and in the pathogenesis of pulmonary diseases in which reactive oxygen species are implicated.

Humans↗
PubMed2000

Tenoxicam i.v. in major gynaecological surgery--pharmacokinetic, pain relief and haematological effects.

This study compared postoperative analgesic dispensation and measures relating to haemostasis following intravenous administration, in a randomized double-blinded manner, of either placebo or tenoxicam 20 mg to 30 women presenting for major gynaecological oncology surgery under a standardized, combined epidural/general anaesthetic technique. Pharmacokinetic disposition of tenoxicam in this patient cohort was also described. There was no objective or subjective alteration in haemostatic function or increase in blood loss, nor any deviation from the normal range of values. Postoperative analgesia during the first 48 hours was delivered to achieve a VAS endpoint of less than five on leg-raising, by a combination of a nurse-controlled low-dose background epidural infusion and patient-administered epidural bolus. Greater VAS variability was observed during the first four postoperative hours (P = 0.08). The tenoxicam group self-administered significantly fewer epidural bolus doses to maintain satisfactory analgesia compared with the placebo group during the first 24 hours (P = 0.004) and 48 hours (P = 0.01) postoperatively. Similar differences between the groups in the total dose of the epidural bupivacaine/fentanyl mixture delivered were described (4 h: P = 0.148; 24 h: P = 0.033; 48 h: P = 0.001) (Figure 2). Despite surgery, transfusion and the use of a renal protective fluid administration strategy, tenoxicam disposition was not greatly different from that widely described for healthy volunteers. There were no significant side-effects and no adverse events attributable to tenoxicam. In this small study we have shown that tenoxicam administered preoperatively reduced the epidural analgesic requirements during the first 48 hours following major gynaecological surgery. There was no clinical or pathological evidence of haematological impairment following a single i.v. administration of tenoxicam 20 mg.

Aged↗