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Biomedical subjects

V Owen

Publications and source records attributed to V Owen.

10 recordsLinked to original sources
PubMed2003

Comparison of morphologic features of intact and ruptured aneurysms of infrarenal abdominal aorta.

INTRODUCTION: Endovascular aneurysm repair (EVAR) has been suggested as a technique to improve outcome of ruptured abdominal aortic aneurysm (AAA). Whether this technique becomes an established treatment will depend, in part, on the anatomy of ruptured AAA. METHODS: The anatomy of intact and ruptured AAA seen in a university department of vascular surgery over 5 years was reviewed. Aneurysm anatomy was assessed with spiral computed tomographic angiography. Suitability for EVAR was assessed from the dimensions of the proximal neck and common iliac arteries. Neck length less than 15 mm, neck width greater than 30 mm, and common iliac artery diameter greater than 22 mm were declared unsuitable for EVAR. RESULTS: Three hundred sixty-three patients with intact AAA and 46 with ruptured AAA were identified. Larger intact aneurysms were significantly associated with longer renal artery-bifurcation distance and more complex proximal neck architecture. In this sample, patients with ruptured AAA were more likely to have larger aneurysms with shorter and narrower proximal necks. Significantly more intact aneurysms were morphologically suitable for endovascular repair compared with ruptured AAA (78% vs 43%; P <.001). CONCLUSIONS: Ruptured AAA are less likely to be suitable for endovascular repair than are intact AAA, most probably because of larger diameter at presentation. Open repair will likely remain the treatment of choice in most patients with ruptured AAA, because of current morphologic constraints of endovascular repair.

Aged↗
PubMed2002

More siblings, less hay fever: more evidence.

The prevalence of allergic rhinitis is increasing. Many authors have noted the prevalence of hay fever is less in children from large families and the 'hygiene hypothesis' has been suggested as an explanation. We looked at the association of sibling number and other variables on the prevalence of hay fever and perennial rhinitis. From 26100 households selected at random, 34362 questionnaires were returned from individuals over 14 years of age; 19.3% had symptoms of hay fever and a further 6.0% had symptoms of perennial rhinitis. A logistic regression analysis showed that for individuals with two or more siblings, the odds of suffering from hay fever are less than the odds for people with no siblings and that these odds decrease as the number of siblings increases. This effect was not found in subjects with perennial rhinitis. This study adds weight to the 'hygiene hypothesis'.

Adolescent↗
PubMed2001

Quantitative myocardial cytokine expression and activation of the apoptotic pathway in patients who require left ventricular assist devices.

BACKGROUND: Molecular mechanisms underlying the deterioration of patients undergoing LV assist device (LVAD) implantation remain poorly understood. We studied the cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta and IL-6 and the terminal stage of the apoptotic pathway in patients with decompensating heart failure who required LVAD support and compared them with patients with less severe heart failure undergoing elective heart transplantation. METHODS AND RESULTS: Myocardial and serum samples from 23 patients undergoing LVAD implantation were compared with those from 36 patients undergoing elective heart transplantation. Myocardial TNF-alpha mRNA (1.71-fold; P<0.05) and protein (3.43+/-0.19 versus 2.95+/-0.10 pg/mg protein; P<0.05) were elevated in the LVAD patients. Immunocytochemistry demonstrated TNF expression in the myocytes. Serum TNF-alpha was also elevated (12.5+/-1.9 versus 4.0+/-0.4 pg/mL; P<0.0001) in the LVAD patients. IL-6 mRNA (2.57-fold higher; P<0.005) and protein (27.83+/-9.35 versus 4.26+/-1.24 pg/mg protein; P<0.001) were higher in the LVAD candidates, as was serum IL-6 (79.3+/-23.6 versus 7.1+/-1.6 pg/mL; P<0.0001). Interleukin-1beta mRNA expression was 9.78-fold higher in the LVAD patients (P<0.001). iNOS mRNA expression was similar to that in advanced heart failure patients and was not further elevated in the LVAD patients. Levels of procaspase-9 (8.02+/-0.91 versus 6.16+/-0.43 oligodeoxynucleotide [OD] units; P<0.01), cleaved caspase-9 (10.02+/-1.0 versus 7.34+/-0.40 OD units; P<0.05), intact and spliced DFF-45 (4.58+/-0.75 versus 2.84+/-0.23 OD units; P<0.05) were raised in LVAD patients, but caspase-3 and human nuclease CPAN were not. CONCLUSIONS: Elevated TNF-alpha, IL-1beta, and IL-6 and alterations in the apoptotic pathway were found in the myocardium and elevated TNF-alpha and IL-6 in serum of deteriorating patients who required LVAD support. These occurrences may have therapeutic implications and influence the timing of LVAD insertion.

Adolescent↗
PubMed2001

Contralateral suppression of transient evoked otoacoustic emissions in patients with cerebello-pontine angle tumor.

OBJECTIVE: During measurement of transient evoked otoacoustic emissions (TEOAEs), acoustic stimulation of the contralateral ear reduces or suppresses TEOAE amplitude. This is thought to be due to the inhibitory control that the medial efferent auditory nerve exerts on outer hair cell (OHC) function. The main aim of this study was to investigate the effect of cerebello-pontine angle (CPA) tumor on the medial efferent nerve pathways to both tumor and non-tumor ears by examining alterations in TEOAE amplitude that result from contralateral acoustic stimulation. DESIGN: Contralateral suppression of TEOAEs using broadband noise was measured preoperatively in 17 patients with unilateral CPA tumor and 17 normally hearing controls, matched for age and gender. RESULTS: The control ears demonstrated significantly more suppression than the tumor and non-tumor ears in the patient group. There was, however, no significant difference in suppression between the tumor and non-tumor ears, and the statistical correlation for suppression between them was high. There was no effect of gender, hearing threshold levels, or size and type of tumor on suppression, although there was an effect of age on suppression in both the control and patient groups where suppression reduced as age increased. Four of the 17 patients had TEOAEs, which were clearly present in the tumor ear despite substantial hearing loss, three of which had no measurable hearing. CONCLUSIONS: It is hypothesized that neural compression by CPA tumor disrupts the medial efferent nerve control mechanism to the OHCs of tumor ears. It also is hypothesized that neural compression reduces transmission of afferent nerve impulses from the tumor ear, which cross over to the medial olivo-cochlear complex and reduce the inhibitory control of OHC function in the non-tumor cochlea.

Acoustic Impedance Tests↗
PubMed2000

Activation of apoptotic and inflammatory pathways in dysfunctional donor hearts.

BACKGROUND: Myocardial dysfunction is common after brain death, but the mechanisms remain unclear. Apoptosis is tightly regulated by enzymes termed the caspases. We have investigated the caspases involved in the terminal part of the apoptotic pathway in dysfunctional (nontransplanted) donor hearts and their relation to inflammatory markers and compared them to hearts with good ventricular function (transplanted donors). METHODS: Thirty-one donor hearts assessed for transplantation were examined. Western blotting was used to measure pro-caspase-9, caspase-3, DFF45, the activated nuclease CPAN and poly (ADP-ribose) polymerase, a DNA repair enzyme inactivated by caspase-3. Caspase-3 activity was also measured. Histologic and immunocytochemical analysis for HLA Class II and Real Time polymerase chain reaction for tumor necrosis factor-alpha and interleukin 6 were performed to detect inflammatory activation. RESULTS: Cleaved caspase-9 was higher (5.53+/-0.6 vs. 3.64+/-0.4 O.D. units, P<0.01) in nontransplanted compared with transplanted donors and there was a trend for higher pro-caspase-9 (5.20+/-1.0 vs. 4.22+/-0.4 O.D. units, P=NS). Levels of pro-caspase-3 were higher in nontransplanted (9.66+/-0.5 vs. 5.15+/-0.5 O.D. units, P<0.00001) donors and cleavage products of caspase-3 were elevated in 14 of 14 nontransplanted and 2 of 17 transplanted donors. Intact DFF-45 (8.94+/-0.36 vs. 6.14+/-0.30 O.D. units, P<0.000005), its spliced product (2.38+/-0.35 vs. 0.4+/-0.21 O.D. units, P=0.0001) and the nuclease caspase-activated nuclease (2.01+/-0.3 vs. 0.66+/-0.16 OD units, P=0.001) were higher in nontransplanted donors. The caspase-3 substrate poly (ADP-ribose) polymerase was higher in nontransplanted (1.16+/-0.13 vs. 0.61+/-0.22 O.D. units, P=0.57) donors. CONCLUSIONS: The caspases are elevated in dysfunctional donor hearts compared with hearts with good ventricular function with a possible link to inflammatory activation supporting the concept that brain death causes inflammatory activation which can lead to apoptosis with a possible important effect on function.

Adult↗
PubMed2000

Elevated tumor necrosis factor-alpha and interleukin-6 in myocardium and serum of malfunctioning donor hearts.

BACKGROUND: Myocardial dysfunction is a common and important problem in donor hearts. The mechanisms responsible remain unclear. We have studied the cytokines tumor necrosis factor (TNF)-alpha and interleukin-6 (IL-6) in the myocardium and serum from donors with myocardial dysfunction (unused donors) and compared them with donors with good ventricular function (used donors) and patients with advanced heart failure (HF). METHODS AND RESULTS: Clinical details and ventricular function were assessed in 46 donors (31 used, 15 unused). Real-time reverse transcription-polymerase chain reaction, Western blotting, and immunocytochemistry were performed on myocardium and immunoassays on serum. TNF-alpha mRNA was 1.6-fold higher in unused than in used donors (P:<0.005) and 1.74-fold higher than in 36 patients with HF. IL-6 mRNA was 2.4-fold higher in unused than in used donors (P:<0.0001) and 4.67-fold higher than in HF (P:<0.0001). Western blotting showed higher TNF-alpha in unused (218. 3+/-6.4, n=4 versus 187.3+/-5.4, n=3 OD units) than used donors (P:<0.05). TNF-alpha expression was localized to cardiac myocytes. Serum TNF-alpha was higher in unused (8.72+/-1.3 pg/mL, n=13) than in used (6.12+/-0.8 pg/mL, n=25, P:<0.05) donors and HF (4.0+/-0.4 pg/mL, n=17, P:<0.005). Serum TNF-alpha receptors did not differ between unused (4.3+/-0.8 and 8.6+/-1.6 ng/mL, n=10) and used (3. 5+/-0.4 and 6.5+/-1.1 ng/mL, n=24) donors. There was a trend for higher serum IL-6 in unused (16.5+/-2.9 pg/mL, n=9) compared with used (13.9+/-1.6 pg/mL, n=26, P:=NS) donors. CONCLUSIONS: This study documented an increase in the expression of TNF-alpha and IL-6 in the myocardium of all donor hearts that was more marked in the dysfunctional (unused) donor hearts. This was accompanied by similar changes in the serum. This might have important therapeutic implications.

Adult↗
PubMed1994

Postmortem changes in blood amitriptyline concentration.

Detailed toxicological studies were undertaken on two suicides by amitriptyline overdose, one with salicylate also. In the first case, 10 initial blood samples taken 21 h after body discovery and an estimated 28 1/2 h after overdose had drug concentration (mg/L) ranges of 2.5-12 for amitriptyline (AM), 0.7-3.1 for nortriptyline (NOR), and 81-244 for salicylate (SAL). Ten blood samples taken 42 h later showed corresponding ranges of 1-39 AM, 0.6-7.0 NOR, and 86-310 SAL. Sample haemoglobin concentrations (range, 8.7-23.5 g/dl) did not correlate with drug concentrations. Postmortem increase in pulmonary vein AM concentration occurred more rapidly than in the pulmonary artery, likely reflecting relative ease of diffusion across the vessel walls from lung (AM, 60 mg/kg). In nine tissue samples, drug concentrations (mg/kg) were highest in the liver: AM, 301; and SAL, 670. Considerable drug residue was present in gastric contents, duodenal contents, and seven sequential small bowel contents. In both cases, sanguineous putrefactive pleural fluid showed higher AM concentrations on the left than on the right (2.0 vs 1.4 and 23 vs 16), likely reflecting diffusion from gastric drug residue. The detailed case data illustrate the intensity and complexity of postmortem drug diffusion from reservoirs in solid organs, such as the lungs, and unabsorbed gastric residue, into the blood and putrefactive fluids.

Adult↗
PubMedDate not supplied

The effects of unilateral pulvinar damage in humans on reflexive orienting and filtering of irrelevant information.

The effects of damage to the pulvinar nucleus of the thalamus in humans on reflexive orienting and selective attention were investigated. In a spatial orienting task three patients with unilateral pulvinar damage determined the location of a visual target that followed a cue that was not informative as to the targets location. Contralesional targets were responded to more slowly than ipsilesional targets. Also, at long cue target intervals patients responses to contralesional targets that appeared at previously cued locations were slower than to non-cued locations indicating that pulvinar damage does not affect inhibition of return. In the selective attention task two of the patients identified a target that appeared at one level of a global-local hierarchical stimulus while ignoring a distractor present at the other level. The distractor indicated either the same response as the target or a different response. Response times to targets in both visual fields were similar as were interference effects from the ignored distractors. These data indicate that engaging attention contralesionally is not impaired in discrimination tasks and that filtering of irrelevant information was not impaired contralesionally.

Attention↗