Search PubMed⌕ Search

Biomedical subjects

S Young

Publications and source records attributed to S Young.

At least 55 records · Page 3Linked to original sources
PubMed2001

A note on the effect of handling quality prior to mixing on behaviour at mixing in pigs.

Previous research has raised the possibility that levels of aggression between pigs may be influenced by their state of arousal and excitement at the time of mixing. This may, in turn, be affected by factors such as the way in which pigs are handled prior to mixing. We attempted the first systematic test of this idea. Sixty four growing pigs were housed in groups of four for 4 weeks to allow them to become familiar with their group mates. Each pig was then tested in a 10min encounter with another pig in an unfamiliar test pen. Pigs were either handled gently (G) or firmly (F) on their way to the encounter. In addition, pigs either met a familiar (F) or an unfamiliar (U) pig in the test pen. Thus, there were four types of encounter (FF, FG, UF, UG) with N=8 tests of each. Two-way analysis of variance showed no effects of handling quality and no interactions between handling quality and familiarity on behaviour during encounters. Unfamiliar pigs showed higher levels of aggressive behaviour. Any fights were stopped immediately. On a second test day, pigs were handled as previously, but all now encountered a familiar individual. Again, there were no effects of handling quality or interactions between handling quality and familiarity. The results, thus, failed to support the idea that the quality of handling prior to mixing influences the levels of aggression subsequently observed.

Journal Article↗
PubMed2001

A battery-powered notebook thermal cycler for rapid multiplex real-time PCR analysis.

A compact, real-time PCR instrument was developed for rapid, multiplex analysis of nucleic acids in an inexpensive, portable format. The instrument consists of a notebook computer, two reaction modules with integrated optics for four-color fluorescence detection, batteries, and a battery-charging system. The instrument weighs 3.3 kg, measures 26 x 22 x 7.5 cm, and can run continuously on the internal batteries for 4 h. Independent control of the modules allows differing temperature profiles and detection schemes to be run simultaneously. Results are presented that demonstrate rapid (1) detection and identification of Bacillus subtilis and Bacillus thuringensis spores and (2) characterization of a single nucleotide polymorphism for the hereditary hemochromatosis gene.

Bacillus subtilis↗
PubMed2001

Bronchoconstrictor reactivity to NKA in allergic dogs: a comparison to histamine and methacholine.

Airway hyperresponsiveness to neurokinin A (NKA) occurs in inflammatory airway diseases like asthma. In this study, bronchoconstrictor reactivity to NKA was measured in beagle dogs neonatally sensitized to and challenged with ragweed. Comparisons were made to histamine and methacholine. Lung resistance (R(L)) and dynamic lung compliance (C(Dyn)) were measured in anesthetized, spontaneously breathing dogs before and after aerosol challenge with NKA, histamine or methacholine. The concentration of these agents increasing R(L)by 25% above baseline (PC(25)) was calculated before and 24 h after aerosolized ragweed challenge. Before ragweed, the bronchoconstrictor reactivity to NKA was four-fold higher in ragweed-sensitized dogs (PC(25)=0.036+/-0.006%) compared to non-sensitized controls (PC(25)=0.177+/-0.030%, P<0.05). On the other hand, there was no difference in the bronchoconstrictor reactivity to histamine or methacholine between these two groups. Twenty-four hours after ragweed challenge to sensitized dogs, NKA reactivity was unchanged from pre-ragweed values but histamine and methacholine reactivity was increased by 2-3-fold. These results demonstrate airway hyperresponsiveness to NKA, histamine and methacholine in allergic beagle dogs although hyperresponsiveness to NKA exists in these allergic dogs before an antigen challenge. This animal model may prove to be useful to evaluate the role of tachykinins in hyperractive airway diseases.

Administration, Inhalation↗
PubMed2001

Safety and efficacy of intravitreal triamcinolone for cystoid macular oedema in uveitis.

PURPOSE: To report the safety and efficacy of intravitreal triamcinolone in the treatment of inflammatory cystoid macular oedema (CMO) in six patients who were resistant to other forms of therapy. METHODS: An open-label unmasked prospective nonrandomized pilot study of six patients with idiopathic uveitis and visually significant macular oedema, resistant to periocular and/or systemic corticosteroid treatment, was carried out. Baseline examination and investigations were performed, including fundus fluorescein angiography, and the patients were given a single intravitreal injection of triamcinolone (4 mg/0.1 mL). The primary outcome measure was angiographic resolution of CMO. Patients were reviewed at intervals of 2-4 weeks for 12 months. RESULTS: A single intravitreal injection of triamcinolone induced clinical and angiographic resolution of inflammatory macular oedema in all patients for varying periods of time up to 6 months. Five patients experienced increased intraocular pressure to 30 mmHg or greater which required treatment. Two patients developed posterior subcapsular cataract. CONCLUSION: One injection of intravitreal triamcinolone was an effective short-term treatment for resistant CMO in uveitis. As with steroids given by other routes, raised intraocular pressure and cataract may occur. As it was so effective in these eyes with resistant CMO, a larger study is warranted to evaluate this form of therapy.

Adult↗
PubMed2001

Maintaining standard scales of reproduction in patient photography using digital cameras.

The use of standard representational photography of patients and the control of the variables in that process, have long been the factor that separates the professional medical photographer from the DIY enthusiast. The published recommendations on how standard representational photography can be set up and maintained have been based on the use of 35-mm film cameras. The common use of digital cameras in departments of medical illustration have brought with them new problems, one of which is the variability of size of the CCD fitted to these cameras. As CCDs are, at the time of writing, smaller than the 35-mm frame size, established protocols need to be changed. This problem can be compounded if a department uses more than one type of camera, each with a different CCD. This paper sets out a method for calculating and calibrating the new scales of reproduction required for digital cameras.

Analog-Digital Conversion↗
PubMed2001

Impact of breast pumping on lactogenesis stage II after cesarean delivery: a randomized clinical trial.

OBJECTIVE: Women at risk for delayed onset of lactation are often advised to pump their breasts before lactogenesis stage II to hasten the timing of this process. The effectiveness of this clinical practice has not been previously evaluated. This study investigates the effects of breast pumping before the onset of lactation on early milk transfer and subsequent breastfeeding duration among women giving birth by cesarean delivery. METHODOLOGY: Sixty women were randomly assigned to either the pumping group (n = 30), which used a double electric breast pump for six 10- to 15-minute sessions from 24 to 72 hours postpartum, or to the control group (n = 30), which held the pump to their breasts without suction for the same amount of time. Milk transfer was assessed by test weighing infants before and after 3 breastfeeding sessions daily. Test weight data were fitted to a second-order polynomial curve, to predict milk transfer over time. RESULTS: Breast pumping between 24 and 72 hours after cesarean delivery did not improve milk transfer. Participants in the pumping group tended to have lower milk transfer than did controls. Primiparae in the pumping group breastfed for ~5 months less than their counterparts in the control group; however, this difference was not statistically significant. CONCLUSIONS: Breast pumping did not improve milk transfer during the first 72 hours postpartum and may negatively affect breastfeeding duration among primiparous women. lactation, lactogenesis, breast milk, breast pumping, milk expression, breastfeeding, cesarean delivery.

Adult↗
PubMed2001

The thymus gland.

This article reviews the embryology, physiology, and pathophysiology of the thymus. The anatomy of this lymphoid organ, the significance of the presence or absence of the thymus radiographically, and the role of the thymus in immunity are also reviewed. Finally, the pathologic presentation of thymic hypoplasia (DiGeorge syndrome) is discussed. Despite advances in modern science, little was known about the thymus, one of the body's key organs in the immune system, until 1961, when Dr. Jacques Miller performed thymectomies in mice. Then it became evident that the thymus played a key role in the body's defense against infection. Since that time, researchers have continued to examine the role of the thymus from fetal life through adulthood.

Antibody Formation↗
PubMed2001

Isolated sonographic markers for detection of fetal Down syndrome in the second trimester of pregnancy.

OBJECTIVE: To determine whether sonographic "markers" are associated with fetal Down syndrome during the second trimester and to estimate the degree of risk of individual markers using likelihood ratios. METHODS: Second-trimester (14-20 weeks) sonographic findings in 186 fetuses with trisomy 21 were compared with a control group of 8728 consecutive control fetuses. Six markers were evaluated: nuchal thickening, hyperechoic bowel, shortened femur, shortened humerus, echogenic intracardiac focus, and renal pyelectasis. RESULTS: Major or structural abnormalities were observed in 31 fetuses with trisomy 21 (16.7%) and 53 control fetuses (0.6%) (P< .001). Some type of sonographic finding (major abnormality, minor marker, or both) was observed in 68.8% of fetuses with trisomy 21 compared with 13.6% of control fetuses (P < .001). An isolated minor or "soft" marker was the only sonographic finding in 42 (22.6%) of 186 fetuses with trisomy 21 compared with 987 (11.3%) of 8728 control fetuses (P < .001). Nuchal thickening (P < .001; likelihood ratio, 11) and hyperechoic bowel (P < .001; likelihood ratio, 6.7) showed the strongest association with trisomy 21 as isolated markers, followed by shortened humerus (likelihood ratio, 5.1), echogenic intracardiac focus (likelihood ratio, 1.8), shortened femur (likelihood ratio, 1.5), and pyelectasis (likelihood ratio, 1.5). Echogenic intracardiac focus was the single most common isolated marker in both affected fetuses (7.1%) and control fetuses (3.9%) but carried a low risk (P= .046; likelihood ratio, 1.8). CONCLUSIONS: A single soft marker is commonly encountered during the second trimester among fetuses with trisomy 21. The risk of fetal Down syndrome, reflected by likelihood ratios, was determined for 6 individual markers. This information can be combined with the a priori risk to estimate the individual patient risk for fetal Down syndrome.

Adult↗
PubMed2001

Failure of antiretroviral therapy to control Varicella zoster retinitis.

The term necrotizing herpetic retinopathies encompasses a spectrum of diseases which includes cytomegalovirus (CMV) retinitis, acute retinal necrosis (ARN) and Varicella zoster retinitis (VZR). Varicella zoster retinitis is a rapidly progressive, necrotizing condition most commonly reported in patients with AIDS. A case of vitreous biopsy-proven VZR is reported in a patient with AIDS that progressed despite immune recovery on highly active antiretroviral therapy (HAART) to a viral load < 50 copies/mL and a CD4 count of 230 cells/microL. This is in contrast to CMV retinitis in which maintenance therapy appears unnecessary once the CD4 count rises and the viral load falls on HAART. Patients with VZR and AIDS should therefore be monitored for reactivation of retinal disease despite HAART-induced remission.

AIDS-Related Opportunistic Infections↗
PubMed2000

HIV-1 integrase inhibitors that compete with the target DNA substrate define a unique strand transfer conformation for integrase.

Diketo acids such as L-731,988 are potent inhibitors of HIV-1 integrase that inhibit integration and viral replication in cells. These compounds exhibit the unique ability to inhibit the strand transfer activity of integrase in the absence of an effect on 3' end processing. To understand the reasons for this distinct inhibitory profile, we developed a scintillation proximity assay that permits analysis of radiolabeled inhibitor binding and integrase function. High-affinity binding of L-731,988 is shown to require the assembly of a specific complex on the HIV-1 long terminal repeat. The interaction of L-731,988 with the complex and the efficacy of L-731, 988 in strand transfer can be abrogated by the interaction with target substrates, suggesting competition between the inhibitor and the target DNA. The L-731,988 binding site and that of the target substrate are thus distinct from that of the donor substrate and are defined by a conformation of integrase that is only adopted after assembly with the viral end. These results elucidate the basis for diketo acid inhibition of strand transfer and have implications for integrase-directed HIV-1 drug discovery efforts.

Acetoacetates↗
PubMed2000

Patient removals. Sitting pretty.

A survey of GPs in Newcastle and North Tyneside found most respondents removed fewer than three patients a year from their lists. Most practices did not have a policy on removals. More than three-quarters of removals were for violence, rudeness or anti-social behaviour. The survey suggests that practices should keep a record of violent incidents and that a facilitator should be made available to help practices with patients who are repeatedly violent.

England↗
PubMed2000

Parental factors affecting respiratory function during the first year of life.

In a prospective, longitudinal, population-based cohort study of familial and environmental influences on the development of wheezing respiratory illness in early childhood, we identified infant length, weight, gender, and exposure to maternal cigarette smoking as significant determinants of lung function during the first year of life. A cohort of 237 infants (106 females: 131 males) was evaluated, and 496 lung function measurements were made between the ages of 1-12 months. Respiratory function was assessed using the rapid thoracic compression technique to obtain maximum expiratory flow at functional residual capacity (V'maxFRC). Parental history of asthma and smoking habits during pregnancy were obtained by questionnaire. Data were analyzed using a longitudinal random effects model. Infants with a parental history of asthma and/or in utero passive smoke exposure were compared to a reference group of infants who had no parental history of asthma and in whom neither parent smoked pre- or postnatally. Boys were found to have a consistently lower V'maxFRC (-21.05 mL.s(-1)) throughout the first year of life in comparison to girls (P < 0.05). Maternal smoking during pregnancy was associated with a lower V'maxFRC in both genders in comparison to unexposed infants (P < 0.05). V'maxFRC was unaffected by parental history of asthma. Gender-specific normative equations for V'maxFRC throughout the first year of life were derived for the infant cohort as a whole and also for subgroups of infants, based on parental asthma and smoking history. We conclude that lung function during the first year of life differs between genders and is adversely affected by in utero passive tobacco smoke exposure. Gender-specific predictive equations for V'maxFRC should be used during infancy.

Cohort Studies↗
PubMed2000

Comparison of morphometric assessment of prevalent vertebral deformities in women using different reference data.

The semiquantitative assessment of vertebral deformities is based on visual evaluation. The quantitative approach is based on different morphometric criteria. This study is aimed at comparing the impact of different reference groups to define normal vertebral shape on the diagnosis of verterbral deformities. Reference normal values were obtained in three groups of women: French, mixed European, and Argentinian. All these women had normal lumbar spine bone mineral density and no vertebral deformities according to the semiquantitative assessment. In a group of 135 women having vertebral deformities according to Genant's semiquantitative assessment, three different morphometric criteria were applied. Morphometric diagnosis disclosed a good agreement with semiquantitative assessment. Agreement of diagnosis was higher for a given cutoff using thresholds obtained in different reference groups (kappa = 0.84-0.96) and lower when different criteria were compared using thresholds obtained in the same reference group (kappa = 0. 75-0.85). When fracture thresholds obtained in three different cohorts were compared separately for the three morphometric criteria, agreement was the highest when the cutoff was based only on the arithmetical mean of vertebral heights and was independent of its standard deviation (SD). Average vertebral height ratios did not differ between the three reference cohorts, whereas SDs of vertebral height ratios were the highest in the mixed European cohort and the lowest in the French cohort (F = 7.41, p < 0.001). In the three groups of women of different nationality, SDs of vertebral height ratios, but not the arithmetical means, were significantly higher in the radiographs of poor quality compared with those of good quality. Thus, the main source of difference of diagnosis was related to different SDs whereas average height ratios were not different. Differences in SDs between the three groups were found to be related, at least partly, to poor quality of radiographs. The impact of the differences between populations seems less important, however, only three countries were compared. These findings suggest that those techniques that take into account the SD of vertebral height ratios will provide different reference values for vertebral morphometry. Because differences in SDs depend mainly on the quality of radiographs, they can be reduced by improving the X-ray technique and by the use of standardized protocols. This variability will result in the identification of a variable number of vertebral deformities in osteoporotic women. These results may be of importance especially for multicentric studies.

Absorptiometry, Photon↗
PubMed2000

Expression of murine adenosine deaminase (ADA) in transgenic maize.

A murine adenosine deaminase (ADA) gene, driven by the maize ubi-1 promoter and intron region, was transformed into embryogenic maize callus, along with a bar and gusA gene-containing plasmid, using microparticle bombardment. Selection in the presence of either the herbicide Basta or the adenosine analogue 2'-deoxyadenosine resulted in transgenic cultures that expressed GUS and accumulated a 41-kD protein that immunoprecipated with an ADA-specific polyclonal antibody. ADA enzyme activity was observed in extracts from transgenic callus as well as regenerated plants and progeny. Culltures expressing ADA grew in the presence of 200 mg/l 2'-deoxyadenosine, a concentration which completely inhibited the growth of non-transgenic cultures. ADA activity appeared to segregate in progency of regenerated plants as a single, dominant Mendelian trait. These results suggest that ADA, in combination with adenosine analogue selection, represents a potentially viable selectable marker system for transgenic maize production.

Adenosine↗
PubMed2000

Inhibition of pulmonary eosinophilia and airway hyperresponsiveness in allergic mice by rolipram: involvement of endogenously released corticosterone and catecholamines.

This study investigates the role of adrenal-derived catecholamines and corticosterone on the inhibition by rolipram, a phosphodiesterase (PDE)-4 inhibitor, of pulmonary eosinophilia and airway hyperresponsiveness (AHR) in allergic mice. The following experimental groups were studied in mice sensitized and challenged with ovalbumin (OVA): normal, adrenalectomized, propranolol (beta-adrenoceptor antagonist) and metyrapone (corticosterone synthesis inhibitor) treated. These interventions were studied both in the absence and in the presence of rolipram. Eosinophil numbers in the bronchoalveolar lavage (BAL) and AHR to methacholine were measured 24 h after OVA challenge. Treatment of sensitized mice with rolipram (0.3 - 10 mg kg(-1), p.o.), inhibited pulmonary eosinophilia and the AHR to methacholine in OVA-challenged mice. Adrenalectomy increased the number of eosinophils in the BAL of OVA-challenged mice but had no effect on AHR to methacholine. Adrenalectomy attenuated both the rolipram-induced inhibition of BAL eosinophilia and AHR to methacholine in OVA challenged mice. Propranolol (10 mg kg(-1), p.o.) had no effect on the inhibition of eosinophilia by rolipram but attenuated the inhibition of AHR to methacholine in OVA challenged mice. On the other hand, metyrapone (10 mg kg(-1), p.o.) attenuated the inhibition of eosinophilia by rolipram but had no effect on the inhibition of AHR to methacholine in OVA challenged mice. Metyrapone-treatment alone increased the number of eosinophils in the BAL of OVA-challenged mice. These results identify an important role for adrenal-derived catecholamines and corticosterone on the inhibition of pulmonary eosinophilia and AHR by rolipram in allergic mice.

Animals↗