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Biomedical subjects

J Young

Publications and source records attributed to J Young.

At least 91 records · Page 5Linked to original sources
PubMed2001

Decreased fibrinolytic potential in South Asian women with ischaemic cerebrovascular disease.

To investigate gender differences in conventional, coagulation and fibrinolytic factors in South Asian ischaemic stroke patients, we compared these variables in 50 South Asian females (SAFP) with 90 South Asian males (SAMP) with ischaemic stroke and in 52 females (SAFC) and 38 males (SAMC) without stroke. Plasminogen activator inhibitor-1 (PAI-1) antigen levels were significantly higher in SAFP compared with SAMP (18.2 vs. 13.3 U/ml, P = 0.04) even after adjustment for known covariates, but there was no difference in PAI-1 antigen levels between males and females in the control group. South Asian females exhibited higher levels of factor VII antigen and FVII:C activity in both stroke patients (114 vs. 99% in males, P = 0.01; 116 versus 104% in males, P = 0.04) and controls (116 vs. 97% in males, P = 0.004; 115 vs. 93% in males, P = 0.01). There were no significant differences in the levels of fibrinogen (3.8 vs. 3.7 g/l), FXIIa (2.2 vs. 2.4 ng/ml), von Willebrand factor (1.8 vs. 1.9 IU/ml) and tissue plasminogen activator (11.4 vs. 12.0 ng/ml) in SAMP and SAFP respectively. These results suggest that South Asian females have increased FVII levels and that females with a history of ischaemic stroke have a decreased fibrinolytic potential in comparison with males.

Adult↗
PubMed2001

Conductive hearing loss in preterm infants with bronchopulmonary dysplasia.

OBJECTIVE: To determine the risk of conductive hearing loss in preterm infants with bronchopulmonary dysplasia (BPD) and preterm controls. METHODOLOGY: The study population consisted of 78 infants with BPD of 26-33 weeks gestation and 78 controls of similar gestational age matched for broad-based birthweight categories. An auditory brainstem response (ABR) audiology was performed shortly before hospital discharge. Visual reinforcement orientation audiometry (VROA) and impedance audiometry were performed at 8-12 months corrected for prematurity. Infants with persistent audiological abnormalities were referred for evaluation to paediatric ENT surgeons. RESULTS: Infants with BPD had a significantly higher rate of ABR abnormalities (BPD: 22%, controls: 9%; P = 0.028). On VROA and impedance audiometry, the infants with BPD also had a higher rate of persistent abnormalities. Following ENT assessment, 22.1% of infants with BPD and 7.7% of controls had persistent conductive dysfunction requiring myringotomy and grommet tube insertion (P = 0.03). Most of these infants had normal ABR audiometry at hospital discharge. CONCLUSIONS: Preterm infants with BPD are at high risk of persistent conductive hearing loss late in the first year of life compared to controls. An ABR audiology conducted at the time of hospital discharge does not predict accurately later conductive hearing problems. Infants with BPD should have routine audiological evaluation toward the end of the first year of life.

Audiometry↗
PubMed2001

Unbuffered highly acidic gastric juice exists at the gastroesophageal junction after a meal.

BACKGROUND & AIMS: Gastroesophageal reflux typically occurs after meals. During dual gastric and esophageal pH monitoring, we observed that postprandial refluxate was often more acidic than the gastric contents. This study aimed to investigate this phenomenon. METHODS: Dual gastric and esophageal pH tracings were analyzed from 40 dyspeptic patients. Dual pH electrode pull-through studies were performed in healthy volunteers to document regional variation in intragastric pH under both fasting and postprandial conditions. The squamocolumnar junction was identified using radio-opaque endoscopic clips. We also examined in vitro partitioning of gastric juice added to a homogenized fatty meal. RESULTS: The dual pH traces confirmed that esophageal refluxate was frequently more acidic than the body of the stomach after meals but not during fasting. The pull-through studies showed a pocket of acid at the gastroesophageal junction that escaped the buffering effect of meals, remaining highly acidic (median pH 1.6) compared with the body of the stomach (pH 4.7; P < 0.001). This proximal acid pocket extended from the cardia across the squamocolumnar junction 1.8 cm into the distal esophagus. The in vitro studies showed that acidic gastric juice could partition on top of a homogenized fatty meal. CONCLUSIONS: After eating, highly acidic unbuffered gastric juice is present at the gastroesophageal squamocolumnar junction and is likely to contribute to the high prevalence of disease at this site.

Adult↗
PubMed2001

Performance evaluation of the microPET P4: a PET system dedicated to animal imaging.

The microPET Primate 4-ring system (P4) is an animal PET tomograph with a 7.8 cm axial extent, a 19 cm diameter transaxial field of view (FOV) and a 22 cm animal port. The system is composed of 168 detector modules, each with an 8 x 8 array of 2.2 x 2.2 x 10 mm3 lutetium oxyorthosilicate crystals, arranged as 32 crystal rings 26 cm in diameter. The detector crystals are coupled to a Hamamatsu R5900-C8 PS-PMT via a 10 cm long optical fibre bundle. The detectors have a timing resolution of 3.2 ns, an average energy resolution of 26%, and an average intrinsic spatial resolution of 1.75 mm. The system operates in 3D mode without inter-plane septa, acquiring data in list mode. The reconstructed image spatial resolution ranges from 1.8 mm at the centre to 3 mm at 4 cm radial offset. The tomograph has a peak system sensitivity of 2.25% at the centre of the FOV with a 250-750 keV energy window. The noise equivalent count rate peaks at 100-290 kcps for representative object sizes. Images from two phantoms and three different types of laboratory animal demonstrate the advantage of the P4 system over the original prototype microPET. including its threefold improvement in sensitivity and a large axial FOV sufficient to image an entire mouse in a single bed position.

Animals↗
PubMed2001

Community hospitals and older people.

Recent health care policy has promoted the community hospital as one remedy for the contracted district general hospital. Unfortunately, a literature review reveals a weak evidence-base to support this policy. Although descriptive studies demonstrate the flexible, multi-purpose role of community hospitals, there is a worrying paucity of clinical outcome studies and no robust health economic evaluation. An important potential role for community hospitals is in the post-acute care of older people. However, evaluation by randomized trial is required to demonstrate effectiveness and cost effectiveness of community hospital transfer compared to alternatives such as remaining in a district general hospital.

Aged↗
PubMed2001

Neural correlates of dual task interference can be dissociated from those of divided attention: an fMRI study.

When people perform two tasks simultaneously, the tasks are often executed slower and with more errors than when they are carried out as single tasks. This is called dual task interference. With functional magnetic resonance imaging (fMRI), we show that concurrently performed visual and somatosensory reaction time (RT) tasks engage almost identical volumes of cortical and subcortical motor structures. Moreover, dual RT tasks engaged additional cortical regions that are not activated by the component RT tasks had they been performed as single tasks. When the inter-stimulus interval was <300 ms, the first task interfered with the second, and a field in the right inferior frontal gyrus (RIFG) appeared with activity correlated with the increased RT to the second stimulus. This activation was spatially distinct from the cortical activity of the main effect of dual task performance. Thus, the performance of single RT tasks, dual RT tasks and dual RT tasks that interfere differ psychophysically and in the brain structures subserving these tasks. A short occupancy of the common motor structures can explain the interference effect. The increased activity of the RIFG correlated with the interference effect is very likely to be a specific outcome of situations where two concurrent tasks interfere with each other. The brain appears to recruit the RIFG for a subsequent (delayed) response when there is interference between dual tasks.

Adult↗
PubMed2001

Hyperplastic polyposis: association with colorectal cancer.

Hyperplastic polyposis is a loosely defined syndrome initially thought not to confer a clinically important predisposition to colorectal cancer. The aim of the current study was to examine the clinical, histologic, and molecular features of a prospective series of cases meeting a strict definition of the condition. Twelve patients were identified, seven of whom had developed colorectal cancer. Most polyps were hyperplastic, but 11 patients also had polyps containing dysplasia as either serrated adenomas. mixed polyps, or traditional adenomas. The mean percentage of dysplastic polyps in patients with cancer was 35%, and in patients without cancer, 11% (p < 0.05). Microsatellite instability (MSI) was present in 3 of 47 hyperplastic polyps and two of eight serrated adenomas. Kras was mutated in 8 of 47 hyperplastic polyps and two of eight serrated adenomas. No polyps showed loss of heterozygosity of chromosomes 5q, 1p, or 18q. Two of seven cancers showed a high level of MSI. It is concluded that hyperplastic polyposis is associated with a high risk of colorectal cancer. Hyperplastic polyps are the dominant type of polyp, but most cases have some dysplastic epithelium. A higher proportion of dysplastic polyps is associated with increased cancer risk. Clonal genetic changes are observed in some hyperplastic polyps and serrated adenomas.

Adenocarcinoma↗
PubMed2001

Contribution of age and gender to outcome of blunt splenic injury in adults: multicenter study of the eastern association for the surgery of trauma.

BACKGROUND: The purpose of this study was to examine the contribution of age and gender to outcome after treatment of blunt splenic injury in adults. METHODS: Through the Multi-Institutional Trials Committee of the Eastern Association for the Surgery of Trauma (EAST), 1488 adult patients from 27 trauma centers who suffered blunt splenic injury in 1997 were examined retrospectively. RESULTS: Fifteen percent of patients were 55 years of age or older. A similar proportion of patients > or = 55 went directly to the operating room compared with patients < 55 (41% vs. 38%) but the mortality for patients > or = 55 was significantly greater than patients < 55 (43% vs. 23%). Patients > or = 55 failed nonoperative management (NOM) more frequently than patients < 55 (19% vs. 10%) and had increased mortality for both successful NOM (8% vs. 4%, p < 0.05) and failed NOM (29% vs. 12%, p = 0.054). There were no differences in immediate operative treatment, successful NOM, and failed NOM between men and women. However, women > or = 55 failed NOM more frequently than women < 55 (20% vs. 7%) and this was associated with increased mortality (36% vs. 5%) (both p < 0.05). CONCLUSION: Patients > or = 55 had a greater mortality for all forms of treatment of their blunt splenic injury and failed NOM more frequently than patients < 55. Women > or = 55 had significantly greater mortality and failure of NOM than women < 55.

Adult↗
PubMed2001

The protein non-folding problem: amino acid determinants of intrinsic order and disorder.

To investigate the determinants of protein order and disorder, three primary and one derivative database of intrinsically disordered proteins were compiled. The segments in each primary database were characterized by one of the following: X-ray crystallography, nuclear magnetic resonance (NMR), or circular dichroism (CD). The derivative database was based on homology. The three primary disordered databases have a combined total of 157 proteins or segments of length.30 with 18,010 residues, while the derivative database contains 572 proteins from 32 families with 52,688 putatively disordered residues. For the four disordered databases, the amino acid compositions were compared with those from a database of ordered structure. Relative to the ordered protein, the intrinsically disordered segments in all four databases were significantly depleted in W, C, F, I, Y, V, L and N, significantly enriched in A, R, G, Q, S, P, E and K, and inconsistently different in H, M, T, and D, suggesting that the first set be called order-promoting and the second set disorder-promoting. Also, 265 amino acid properties were ranked by their ability to discriminate order and disorder and then pruned to remove the most highly correlated pairs. The 10 highest-ranking properties after pruning consisted of 2 residue contact scales, 4 hydrophobicity scales, 3 scales associated with.-sheets and one polarity scale. Using these 10 properties for comparisons of the 3 primary databases suggests that disorder in all 3 databases is very similar, but with those characterized by NMR and CD being the most similar, those by CD and X-ray being next, and those by NMR and X-ray being the least similar.

Amino Acids↗
PubMed2001

Determinants of social outcome measured by the Frenchay Activities Index at one year after stroke onset.

We report an investigation to identify patient factors which influence social outcome measured by the Frenchay Activities Index at 12 months after a disabling stroke. Using data from a previous randomised trial a logistic regression model identified gait speed, prestroke Frenchay Activities Index, the Abbreviated Mental Test score, sensory neglect, chronic obstructive airways disease and left hemiplegia as significantly associated with 12-month social outcome scores. The model correctly predicted the social outcome for 78% of the study population and, when tested on a second data set, correctly predicted 76% of cases. These patient factors provide insight into social activity recovery after stroke and could be considered as stratification factors in future community stroke randomised trials.

Activities of Daily Living↗
PubMed2001

Insulin resistance and elevated levels of tissue plasminogen activator in first-degree relatives of South Asian patients with ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: South Asians in the United Kingdom suffer from an increased mortality from cerebrovascular disease compared with whites. Evidence suggests that the relatives of white stroke patients are at increased risk of vascular disease. The aim of this study was to investigate atherothrombotic risk factors in the first-degree relatives of South Asian patients suffering from ischemic cerebrovascular disease and to compare them with South Asian subjects free from clinically detectable cerebrovascular disease. METHODS: We compared 143 relatives of South Asians with ischemic stroke (South Asian relatives group) with 146 South Asian control subjects from West Yorkshire, UK. RESULTS: The ages and ethnic and sex distributions of South Asian relatives and South Asian controls were similar. There were no significant differences in body mass index, waist-hip ratio, number of current smokers, and past medical history of hypertension, diabetes mellitus, or myocardial infarction between the 2 groups. Fasting blood glucose, glycosylated hemoglobin (HbA(1c)), total cholesterol, triglycerides, and HDL cholesterol were similar in the 2 groups. Fasting insulin (South Asian relatives, 12.0; South Asian controls, 8.5 mU/L; P<0.0001) (independent of tissue plasminogen activator) and insulin resistance (derived by Homeostasis Model Assessment) (South Asian relatives, 2.7; South Asian controls, 1.9; P=0.001) were significantly raised in stroke relatives. Stroke relatives showed elevated levels of tissue plasminogen activator (South Asian relatives, 11.6; South Asian controls, 8.4 ng/mL; P<0.0001), which was independent of plasma insulin. There were no differences in plasminogen activator inhibitor antigen or activity between the groups. CONCLUSIONS: South Asians stroke relatives exhibit hyperinsulinemia, increased insulin resistance, and increased tissue plasminogen activator levels. These observations might account for increased susceptibility to atherothrombotic disease in this ethnic group.

Adolescent↗
PubMed2001

Patterns of hemiparesis recovery in lacunar and partial anterior circulation infarct stroke syndromes.

OBJECTIVE: To investigate patterns of hemiparesis recovery in lacunar (LACI) and partial anterior circulation infarct (PACI) stroke syndromes. DESIGN: Prospective observational study. SETTING: District general hospital and stroke rehabilitation ward. SUBJECTS: Forty-seven patients (25 LACI and 22 PACI) with a first-ever stroke causing a hemiplegia. Average age 76.4 years (range 59-88). MEASURES: Outcome measures assessed disability (Barthel Index), limb power (Motricity Index) and mobility (Rivermead Mobility Index) at baseline and 3, 6, 9, 12, 16 and 24 weeks post stroke onset. RESULTS: The time to maximum recovery, time to 50% recovery and area under the recovery curve was determined for each of the outcome measures. There were no statistical differences between these recovery parameters between the PACI and LACI stroke syndromes. CONCLUSION: Classification of hemiplegic stroke into PACI or LACI syndromes does not distinguish distinctive recovery patterns.

Aged↗
PubMed2001

A survey of physiotherapy and occupational therapy provision in UK nursing homes.

BACKGROUND: Nursing homes in the UK are increasingly regarded as potential rehabilitation facilities for disabled older people. OBJECTIVE: To determine the current physiotherapy and occupational therapy provision to UK nursing homes. SAMPLE: Four hundred private nursing homes in England, Scotland and Wales were selected by stratified proportional random sampling and surveyed by postal questionnaire. RESULTS: The response rate for the effective sample was 346/355 (97%). Only 10% of residents were in current receipt of physiotherapy, mostly through private physiotherapists employed by the nursing homes. Occupational therapy was being provided to only 3.3% of residents. CONCLUSION: Older people in nursing homes in the UK currently receive little physiotherapy and occupational therapy input and are particularly isolated from National Health Service (NHS) services.

Aged↗
PubMed2001

The postmenopausal ovary is not a major androgen-producing gland.

It is currently believed that the postmenopausal ovary remains a gonadotropin-driven, androgen-producing gland. However, the adrenal contribution to circulating androgen levels may explain some conflicting results previously reported. In addition, the steroidogenic potential and gonadotropin responsiveness of the postmenopausal ovary have not been recently reassessed. Plasma T, bioavailable T, free T, androstenedione (Adione), and dehydroepiandrosterone sulfate levels were measured in postmenopausal or ovariectomized women with complete adrenal insufficiency, compared with women with intact adrenals. A stimulation human chorionic gonadotropin test (on d 0, 3, and 6) was performed in postmenopausal women with adrenal insufficiency. Dexamethasone was administered for 4 d in postmenopausal women with intact adrenals. Intraovarian T and androstenedione were also measured in homogenates of ovarian tissue from postmenopausal women. Immunocytochemistry was performed on postmenopausal ovaries and premenopausal controls to detect the presence of steroidogenic enzymes (P-450 aromatase, P-450 SCC, 3beta HSD, and P-450 C17) and gonadotropin receptors. Plasma androgen levels were below or close to the limit of the assay in all women with adrenal insufficiency. They were similar in postmenopausal and oophorectomized women with normal adrenals. No hormonal changes were observed after human chorionic gonadotropin injections in women with adrenal insufficiency. In contrast, a dramatic decrease of all steroids was observed after dexamethasone administration in postmenopausal women with intact adrenals. Intraovarian T and androstenedione levels were negligible in postmenopausal ovarian tissue. P-450 aromatase was absent from the 17 ovaries studied, and the enzymes for androgen biosynthesis were either absent (n = 13) or present in very low amounts (n = 4). In all the postmenopausal ovaries, FSH and LH receptors were completely absent. In the absence of adrenal steroids, postmenopausal women have no circulating androgens. This result is consistent with the immunocytochemical studies showing the almost constantly absent steroidogenic enzymes and LH receptors in the postmenopausal ovary. Thus, the climacteric ovary is not a critical source of androgens. The arrest of androgen secretion after menopause may impact significantly on women's health.

Adrenal Glands↗
PubMed2001

Normal pituitary hypertrophy as a frequent cause of pituitary incidentaloma: a follow-up study.

Enlargement of the pituitary gland is a frequent cause of incidentaloma and of referrals to endocrinologists for hormonal evaluation and therapeutic advice. In neuroradiological series, 25-50% of healthy women who are 18-35 yr old have a convex superior pituitary contour, but pituitary height exceeds 9 mm in less than 0.5% of cases. This study was performed to provide thorough clinical and hormonal data and long-term endocrinological and imaging follow-up data on subjects with incidentally discovered pituitary hypertrophy (height > 9 mm). Seven eugonadal nulliparous women, 15-27 yr old, referred between 1989 and 1998 with incidentally diagnosed pituitary gland enlargement (height > 9 mm) and a suspected pituitary tumor, were studied. At presentation and at yearly intervals, PRL plasma levels and corticotropic, somatotropic, and thyrotropic pituitary function were measured; and pituitary dimensions and signal on magnetic resonance imaging (MRI), before and after iv gadolinium-diethylene-triamine-pentaacetic acid injection, were assessed. PRL plasma levels were normal; and corticotropic, somatotropic, and thyrotropic pituitary function was considered normal in all cases. In all the women, the upper boundary of the pituitary was convex, on MRI, and touched the optic chiasm in four cases. The width and anteroposterior diameter of the gland were normal. The pituitary itself seemed normal, with a homogeneous signal, on plain and dynamic studies with iv contrast injection. Despite normal initial hormone values, two women underwent surgery, by the transsphenoidal approach, in another center. During surgery, the pituitary seemed normal in both cases, with no evidence of tumoral or inflammatory processes. Biopsy specimens showed the morphologic characteristics of a normal, nonhyperplastic pituitary gland. All seven women were seen at yearly intervals for 2-8 yr (median, 4 yr). Clinical and hormonal status remained stable, as did the structure and size of pituitary, on serial MRI. No tumor formation occurred, supporting the diagnosis of physiologic hypertrophy of the pituitary gland. In conclusion, these observations suggest that careful examination of MRI results may help to distinguish physiologic pituitary hypertrophy from pituitary tumors and infiltrating lesions. The former diagnosis is confirmed by normal baseline pituitary function in extensive hormonal tests. Correct identification of such patients is important to avoid unnecessary pituitary surgery and costly MRI surveillance.

Adenoma↗