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PubMed2003

Topology: a novel method to describe branching patterns in Peronospora viciae colonies.

Topology provides a novel means to describe branching patterns and has not been applied to fungal colonies previously. For any branched structure, various topologies are possible, and these lie between two extremes, a herringbone pattern (main axis with primary laterals) and a dichotomous pattern (highly branched system). We applied topological methods to colonies of Peronospora viciae 48 h after inoculation of Pisum sativum leaves. The methods are based on two simulations, one developed for channel networks such as found in river systems and another for biological systems. Although not a true herringbone form, the Peronospora viciae colonies have a strong herringbone element within their growth pattern. All 25 colonies analysed fell into the random distribution according to the confidence limits calculated from simulations for biological systems. These confidence limits, however, represent the percentile distribution of all simulated networks, and only those structures with a perfect herringbone or dichotomous topology fall outside the range. The tendency of P. viciae colonies towards herringbone growth is reflected by the topological indices for altitude and external pathlength (a(obs)/E(a) and pe(obs)/E(pe), where a = altitude, pe = external pathlength, obs = observed for the P. viciae colonies and E = expected values for random growth), and the slope of the regression analysis for a(obs) and pe(obs). We consider this trend as significant because it was consistent for all but one of the colonies, and implies that growth can be envisaged as an intermediate between random and herringbone topology. It is proposed that initial herringbone growth may reflect a strategy that is aimed at overcoming host resistance, achieving rapid colonisation of infected tissue and maximising the potential for nutrient acquisition. This topology would also increase the likelihood of finding a compatible mating type for reproduction between heterothallic isolates.

Models, Biological↗

PubMed2006

Comparison of Luneau SA disposable and Goldmann applanation tonometer readings.

PURPOSE: To test the agreement of intraocular pressure (IOP) measurements made with Luneau SA applanators and Goldmann applanator. MATERIALS AND METHODS: A single-blind crossover trial. IOPs were measured in both eyes of subjects with both applanators. Type of applanator was alternated to eliminate systematic bias. Multiple observers were used. Observers were blind to the scale while performing measurements but not to the type of applanator used. The appearance of the meniscus was assessed semiquantitatively. All measurements were combined and presented in a Bland-Altman plot. RESULTS: A total of 140 eyes of 79 subjects were tested by seven observers. The range of measurements was 6-45 mmHg (mean 17.8 mmHg) for the Goldmann applanator. On average, the Luneau SA applanator (range of measurements 4-36 mmHg) gave a measurement of 2.35 mmHg less than the Goldmann standard. The standard deviation of these differences was 2.13 mmHg, giving an upper 95% confidence limit of 6.53 mmHg and a lower 95% confidence limit of -1.83 mmHg. The measurements agreed in only 24 out of 140 instances. In 28 eyes, the disposable tonometer end point was difficult to assess owing to excessively thick rings. Linear extrapolation suggests an increase in difference with increasing IOP. CONCLUSION: The inter-head inaccuracy, tendency to underestimate IOP, and lack of systematic inaccuracy make a corrective algorithm impossible to formulate. The range of variation between the Luneau SA disposable applanator and the Goldmann standard is sufficiently large to influence clinical management decisions. We speculate that one explanation is the interaction of the tonometer with the tear film, making end point determination difficult. Further research is being undertaken.

Cross-Over Studies↗

PubMed2001

Changes in management of diabetic retinopathy by Australian ophthalmologists as a result of the NHMRC clinical guidelines.

PURPOSE: To document changes in management of diabetic retinopathy by Australian ophthalmologists after release of the National Health and Medical Research Council (NHMRC) clinical guidelines. METHODS: Self-administered questionnaires were mailed to Australian ophthalmologists prior to release of the NHMRC guidelines for the management of diabetic retinopathy, and at one and 2.5 years after release of the guidelines. The questionnaires elicited information about current management practices in relation to diabetic retinopathy RESULTS: The response rate for the baseline and two follow-up surveys was 82%, 81%, and 80%, respectively. More than 85% of the ophthalmologists responded that the guidelines were useful in improving management, were easy to understand, and were already part of their routine clinical practice. A relatively small percentage (12%) felt that the guidelines made recommendations that were not practical or feasible. Contrary to the NHMRC guidelines, at the second follow-up survey, only 50% of the ophthalmologists said that they would almost never perform fluorescein angiography in eyes with mild non-proliferative diabetic retinopathy. The change from baseline to the second follow-up in the percentage of ophthalmologists who would perform cataract surgery after treating clinically significant macular oedema (as advised by the NHMRC guidelines) was statistically significant (baseline = 83.7%, 95% confidence limit = 80.4, 87.0; second follow up = 90.4, 95% confidence limit = 87.3, 93.5). CONCLUSIONS: Distribution of the printed NHMRC Clinical Practice Guidelines: Management of Diabetic Retinopathy and full colour Retinopathy Chart resulted in a significant change in the recommended order of treatment of clinically significant macular oedema. However no significant change in the use of fluorescein angiography was documented.

Australia↗

PubMed1991

Evaluation of the clinical usefulness of capnography curves during a hyperventilation provocation test in the diagnosis of hyperventilation syndrome.

We evaluated the diagnostic usefulness of capnography curves during and following a hyperventilation provocation test (HVPT) in the hyperventilation syndrome (HVS). The diagnosis of HVS was based on the Nijmegen questionnaire and on the reproduction of symptoms during HVPT. Capnography curves of 40 HVS patients, 40 non-HVS patients with psycho-somatic complaints and 26 healthy controls were analyzed. There was no difference in baseline end-tidal CO2-level (FETCO2) between the 3 groups. The spontaneous fall of FETCO2 during the adaptation phase was clearly different in HVS patients versus non-HVS patients or controls: -0.12 mmol/l (95% confidence limits -0.18 to -0.06) versus +0.01 mmol/l (95% confidence limits -0.04 to +0.16) (p = 0.002). The 3 minutes FETCO2 recovery ratio and the 5 minutes ratio were not significantly different between the groups. In conclusion, in this study the spontaneous fall of FETCO2 during the adaptation phase of the HVPT was the only valuable part of the capnography test to discriminate between HVS and non-HVS patients.

Carbon Dioxide↗

PubMed1990

Effect of long-term administration of testosterone oenanthate on sympathetic neurotransmission to rat isolated seminal vesicles.

1. The effects of prolonged administration of testosterone oenanthate (TE) on sympathetic neurotransmission to the rat isolated seminal vesicle were examined. 2. TE was administered at either 1.2 or 2.4 mg/kg subcutaneously (s.c.) thrice weekly for 8 weeks. A separate group of rats was administered the vehicle, sesame oil, 0.5 mL/kg, s.c. at the same regime and used as controls. TE administration increased plasma testosterone and dihydrotestosterone levels and seminal vesicle weights. TE 2.4 mg/kg suppressed fertility in male rats. 3. The mean -log EC50 values of adrenalin and noradrenaline in seminal vesicles from the control group were 5.30 (95% confidence limits: 5.14, 5.58; d.f. = 14) and 4.92 (95% confidence limits: 4.56, 5.49; d.f. = 14) respectively. Neither of these estimates were modified by TE administration. 4. The mean noradrenaline content (microgram/tissue) in seminal vesicles from control rats was 0.88 +/- 0.09 microgram/tissue. This did not change with TE treatment. Tissue noradrenaline concentration (microgram/g tissue), on the other hand, decreased by more than 50% in preparations from rats treated with TE. This was paralleled by a decrease in the density of catecholamine fluorescence. 5. Mean responses to field stimulation (20 pulses, 60 V dial setting, 2 ms, 1-70 Hz) appeared to decrease in preparations from TE treated groups; this decrease was, however, not statistically significant (P greater than 0.05; d.f. = 15). 6. It is concluded that prolonged administration of testosterone oenanthate to rats, at doses sufficient to suppress fertility, decreases the density of sympathetic innervation to the seminal vesicle by increasing smooth muscle mass. Treatment does not, however, modify the responses of this preparation to exogenously added catecholamines.

Animals↗

PubMed1992

Use of a modified shell vial technique to quantitate cytomegalovirus viremia in a population of solid-organ transplant recipients.

A quantitative modification of the shell vial assay was used to investigate cytomegalovirus viremia in solid-organ transplant recipients. The level of viremia detected in 109 of 407 specimens ranged from 0.02 to 28 infectious foci per 100,000 leukocytes. By using a Poisson model, a technique was developed to determine 95% confidence limits for the measured levels of viremia. These confidence limits were used to determine the level of viremia that could be excluded by culturing a given number of cells. Longitudinal assessment of two transplant recipients revealed different patterns of viremia and demonstrated that significant disease sometimes occurred with low-level viremia. On the basis of the results of the studies, culture of at least 4 x 10(6) leukocytes is recommended for the sensitive detection of cytomegalovirus viremia.

Cytomegalovirus↗

PubMed1991

Inability to fully extend the injured elbow: an indicator of significant injury.

Elbow injuries are commonly seen in accident departments. Patients with possible bony injuries to the elbow were assessed to see if inability to fully extend the elbow was a good indicator of bony injury and hence the need for X-ray. The sensitivity of this test was 90.7% (95% confidence limits 80.7-100.7) and the specificity 69.5% (95% confidence limits 60.3-78.7). Use of this simple test would reduce both radiography costs and unnecessary exposure to radiation.

Adolescent↗

PubMed1985

Increased responsiveness to methacholine and histamine after challenge with ultrasonically nebulised water in asthmatic subjects.

Responsiveness to inhaled methacholine was compared before and 40-60 minutes after a challenge with ultrasonically nebulised water (UNH2O) in 16 asthmatic patients. The sensitivity to methacholine increased after UNH2O challenge (p less than 0.001). The mean dose of methacholine producing a 20% fall in forced expiratory volume in one second was 0.4 (95% confidence limits 0.2, 0.8) mumol, compared with 0.9 (95% confidence limits 0.5, 1.6) mumol in the first methacholine challenge. When the study was repeated in six asthmatic patients with histamine substituted for methacholine, five of the patients were significantly more sensitive to histamine after UNH2O challenge. It is concluded that challenge with UNH2O produces an increase in airway responsiveness.

Adult↗

PubMed1981

Scintigraphic diagnosis of gastrointestinal bleeding with 99mTc-labeled blood-pool agents.

Abdominal scintigraphy with 99mTc-labeled albumin or red blood cells was used in 68 patients to localize gastrointestinal bleeding or confirm that it had stopped. Acute, active bleeding was identified in 33 patients; characteristic patterns of bleeding from the stomach, biliary passages, small intestine, and colon are shown. Sensitivity was 0.86 (95% confidence limits, 0.57-0.98) and specificity was 1.0 (95% confidence limits, 0.82-1.0) in 33 patients who had scintigraphy and endoscopy performed in succession. Abdominal scintigraphy appears to be a valuable supplement to conventional diagnostic methods. In upper gastrointestinal bleeding, scintigraphy should be considered when endoscopy fails. In lower intestinal bleeding, scintigraphy should be the method of choice.

Adolescent↗

PubMed1989

Characterization of A1 adenosine receptors in atrial and ventricular myocardium from diseased human hearts.

The purpose of the present study was to characterize adenosine receptors in human atrial and ventricular myocardium. In isolated electrically driven preparations, adenosine produced "direct" negative inotropic effects in atrial myocardium (AT). In ventricular myocardium (VE), it only had negative inotropic properties when force of contraction had been stimulated with isoprenaline ("indirect" effect), but it has no inotropic effect alone. The adenosine receptor antagonist 8-phenyltheophylline antagonized the "direct" and "indirect" effects; these findings indicated that both effects were mediated by adenosine receptors. In cardiac membranes from human AT and VE, adenosine receptors were characterized with [3H]-8-cyclopentyl-1,3-dipropylxanthine (DPCPX) binding. The effects of agonists R-(-)-N6-phenylisopropyladenosine (R-PIA), S-(+)-N6-phenylisopropyladenosine (S-PIA), and 5'-(N-ethylcarboxamido) adenosine (NECA) and the effects of guanine nucleotides [Gpp(NH)p] were studied also. The antagonist affinities as judged from the apparent affinity, Kd, of [3H]DPCPX were similar in AT (2.2 nmol/l; 95% confidence limits, 1.4-3.7) and VE (1.8 nmol/l; 95% confidence limits, 1.0-3.0). The number of adenosine receptors was 1.7 times greater in AT (26.9 +/- 2.33 fmol/mg protein; n = 5) than in VE (16.2 +/- 2.3 fmol/mg protein; n = 5). High and low affinity states of adenosine receptors evaluated with the influence of Gpp(NH)p on agonist competition with R-PIA were similar in AT or VE. The rank orders of potency for agonists (R-PIA greater than S-PIA greater than NECA) and antagonists (DPCPX greater than 8-phenyltheophylline greater than theophylline) were characteristic for the A1 receptor subtype. It is concluded that A1 adenosine receptors exist in the human myocardium. Since binding properties were similar in AT and VE, the same A1 adenosine receptor probably couples to different effectors in a similar guanine nucleotide-dependent way. [3H]DPCPX is the first radiolabeled antagonist ligand that allows detection of A1 adenosine receptors and their coupling in the human myocardium.

GTP-Binding Proteins↗

PubMedDate not supplied

Use of sodium hydroxide solution to clear partially occluded vascular access ports.

Gradual vascular access port or tunneled central venous catheter occlusion during total parenteral nutrition is a common complication of unknown etiology, usually unresponsive to treatment with urokinase, ethanol, or hydrochloric acid. After establishing safety with regard to catheter materials and efficacy in dissolving the occluding substance in vitro, we treated a total of 13 vascular access ports (10 patients) that had occluded gradually during "three-in-one" total parental nutrition by slow perfusion with 10 to 20 mL of 0.1 mmol/mL sodium hydroxide solution. We found a mean increase in flow (results are flow rates under gravity-dependent vascular access port inlet pressure of 1.5 kPa) from 37 microL/s (95% upper confidence limit, 45 microL/s) to 75 microL/s (95% lower confidence limit, 64 microL/s; p < .001). For normal use, a flow of 50 microL/s is sufficient. There were no side effects. Five vascular access ports remained in excellent function during a follow-up period of 9 months. The others had reocclusions, but the partial reocclusions could be treated successfully.

Catheters, Indwelling↗

PubMed1993

Screening for anti-HIV and HBsAg in pooled sera from a clinical chemistry section as a tool for epidemiological survey.

With the aim of estimating the unknown spread of HIV into the general society, a program for testing pooled routine sera from a clinical chemistry laboratory has been tried. Serum samples obtained from the daily inflow of blood tubes at the Clinical Chemistry Laboratory, Malmö General Hospital, and not labelled as risk samples for blood-borne infection(s), were collected and pools of up to ten sera each were constructed according to a special protocol. All serum pools were screened for anti-HIV and HBsAg. During the 32-months period of the study 3,016 serum pools from men and the same number from women were collected and analysed. These pools together contained sera from 26,468 male and 26,891 female patients, respectively. Altogether 33 male and 2 female pools were found anti-HIV positive. Anti-HIV-positive males appeared in all age groups, without significant difference between the groups. Two female pools from the age group 15 to 24 years were anti-HIV positive; these samples were drawn during the last year of testing. HBsAg was detected in 189 male and 129 female pools. From 1989 to the first half of 1991 the mean anti-HIV prevalence among the male samples investigated was 0.10%, with 95% confidence limits from 0 to 0.25%. If the upper confidence limit is exceeded in the future, this could be a warning of increased spread of HIV of in society.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Cell proliferation and Ca(2+)-calmodulin dependent protein kinase activation mediated by alpha 1A- and alpha 1B-adrenergic receptor in HEK293 cells.

AIM: To examine the ability of alpha 1-AR subtypes on proliferation and Ca(2+)-calmodulin dependent protein kinase (CCDPK, formerly called MAPK) activation in transfected human embryo kidney 293 (HEK293) cells. METHODS: pREP8/alpha 1A-AR, pREP4/alpha 1B-AR, and pREP9/alpha 1D-AR were transfected, respectively, into HEK293 cells by calcium phosphate precipitation. The expression of alpha 1-AR was detected by radioligand binding assays. DNA synthesis was measured by [3H]thymidine incorporation. CCDPK activity was determined by immunoprecipitation method and myelin basic protein was used as substrate. RESULTS: Three clonal HEK293 cell lines stably expressing alpha 1A- or alpha 1B- or alpha 1D-AR were chosen and characterized by radioligand binding assay with receptor densities of about 0.6 nmol.g-1. Treatment with norepinephrine (NE) in the presence of propranolol for 24 h increased DNA synthesis in HEK293/alpha 1A- or HEK293/alpha 1B-AR cells concentration-dependently, with EC50 values of 48.8 nmol.L-1 (95% confidence limits 9.7-246 nmol.L-1) and 8.4 nmol.L-1 (95% confidence limits 2.1-32.9 nmol.L-1), respectively. The increase of DNA synthesis induced by NE 10 mumol.L-1 was 201% +/- 28% and 269% +/- 44% of basal, and the activation of CCDPK was 171% +/- 84% and 292% +/- 92% of basal in HEK293/alpha 1A-AR and HEK293/alpha 1B-AR cells, respectively. Preincubation with prazosin completely abolished NE-induced CCDPK activation in HEK293/alpha 1A- and alpha 1B-AR cells. Those changes were not found in HEK293/alpha 1D-AR cells. CONCLUSION: The activation of alpha 1A- or alpha 1B-AR but not alpha 1D-AR induces cell proliferation.

Adrenergic alpha-Agonists↗

PubMed2000

Anti-HIV-1 activity of trichobitacin, a novel ribosome-inactivating protein.

AIM: To determine whether trichobitacin, a novel ribosome-inactivating protein purified from the root tubers of Trichosanthes kirilowii, possesses the anti-HIV activity. METHODS: The inhibition of syncytial cell formation induced by human immunodeficiency virus type 1 (HIV-1) was determined under microscope, reduction of HIV-1 p24 antigen expression level was measured by ELISA, and decrease in numbers of HIV-1 antigen positive cells in acutely and chronically infected cultures were detected by indirect immunofluorescence assay. RESULTS: Trichobitacin was found to greatly suppress syncytial cell formation induced by HIV-1 and to markedly reduce both expression of HIV-1 p24 antigen and the number of HIV antigen positive cells in acutely but not chronically HIV-1 infected culture. The median inhibitory concentration (IC50) in inhibition of syncytial cell formation and HIV antigen positive cells were 5 micrograms.L-1 (95% confidence limits: 1.3-20 micrograms.L-1) and 0.09 mg.L-1 (95% confidence limits: 0.011-0.755 mg.L-1), respectively. CONCLUSION: Trichobitacin is a novel ribosome-inactivating protein with anti-HIV-1 activity.

Anti-HIV Agents↗

PubMed1988

The non-human primate: a possible model for human genetically determined polymorphisms in oxidative drug metabolism.

Genetic polymorphisms of drug oxidation are major determinants of interindividual variations in drug response and toxicity. Many animal models, including rats, have been used for clinical investigations of pharmacogenetics. However, because of large interspecies differences, these data are difficult to extrapolate to humans. We therefore phenotyped 64 non-human primates for debrisoquine and mephenytoin polymorphisms and identified poor metabolizers of both drugs. The frequency of poor metabolizers was 14% for debrisoquine (95% confidence limits, 6.5-25%) and 3% for mephenytoin (95% confidence limits, 0.5-10%). If family studies demonstrate a genetic basis for the two independent defects, this animal species could be used for in vivo and in vitro pharmacogenetic investigations.

Animals↗

PubMed1996

Effects of tetrandrine on cytosolic free calcium in cultured rat myocardial cells.

AIM: To study the effects of tetrandrine (Tet) on myocardium. METHODS: Using Fura 2-AM and AR-CM-MIC cation measurement system, cytosolic free calcium ([Ca2+]i) was examined in cultured rat single myocardial cells. RESULTS: The resting [Ca2+]i was 90 +/- 12 nmol.L-1 in the presence of Ca2+ 1.3 mmol.L-1 in Hanks' solution. Tet 1-100 mumol.L-1 had no effect on the resting [Ca2+]i, but 10-100 mumol.L-1 depressed the [Ca2+]i elevation when extracellular Ca2+ was 5 mmol.L-1. Tet 1-100 mumol.L-1 inhibited KC1 (30 and 60 mmol.L-1) induced [Ca2+]i elevation in a concentration-dependent manner, the IC50 value was 8.8 mumol.L-1 (95% confidence limits: 3.3-23.7 mumol.L-1) and 6.9 mumol.L-1 (95% confidence limits: 2.8-17.4 mumol.L-1), respectively. Norepinephrine (NE) 10 mumol.L-1 caused a rapid increase in [Ca2+]i in the presence or absence of extracellular Ca2+, Tet 30-100 mumol.L-1 only decreased the former. Tet 10-100 mumol.L-1 also decreased ouabain (Oua)-induced elevation in [Ca2+]i. CONCLUSION: Tet had inhibitory effects on Ca2+ transmembrane movement, but it is not a selective calcium channel blocker in rat myocardial cells.

Alkaloids↗

PubMed1998

Combined effect of smoking and human papillomavirus type 16 infection in cervical carcinogenesis.

To study the combined effect of smoking and human papillomavirus (HPV) type 16 infection in high-grade cervical intraepithelial neoplasia, we analyzed data from a Norwegian population-based case-control study including 90 patients and 216 controls, 20-44 years of age. We assessed HPV-16 status both by polymerase chain reaction detecting virus DNA and by enzyme-linked immunosorbent assay detecting antibodies against virus capsid. Smoking was associated with cervical intraepithelial neoplasia grade II-III in HPV-16-positive individuals. Using the jointly unexposed (HPV-16 DNA-negative never-smokers) as the reference group, we determined the risk of cervical intraepithelial neoplasia grade II-III in HPV-16 DNA-positive never-smokers and HPV-16 DNA-positive ever-smokers (odds ratio = 15.7; 95% confidence limits = 3.2, 76.5, and odds ratio = 65.9; 95% confidence limits = 22.3, 194.3, respectively). The estimated proportion of cases among HPV-16-positive smokers that is attributable to the interaction between the two causes is 74%, based on HPV-16 DNA positivity.

Adult↗

PubMed1988

Consistency of circadian blood pressure pattern assessed by non-invasive monitoring and cosinor analysis in hospitalized hypertensive patients.

Non invasive blood pressure monitoring using an automatic Nippon Colin recorder was performed in 20 hospitalized hypertensive patients every 15 min during a 4-day study period. A chronobiologic analysis of the data was performed in order to test the consistency of the whole-day blood pressure pattern. Halberg's method of single cosinor was used to determine the values and the confidence limits of the following parameters of 24-hour rhythmic changes: mesor (rhythm-adjusted 24-hour average), amplitude (24-hour variability estimate), acrophase (clock hour of maximum BP level). The variation of the above parameters during the four 24-hour periods was found to be within 9 mmHg for the systolic mesor, 6 mmHg for the diastolic mesor, 5 mmHg for the systolic amplitude, 4 mmHg for the diastolic amplitude, 55 min for the systolic acrophase, 60 min for the diastolic acrophase. The same parameters were also calculated in 48-hour, 72-hour and 96-hour long time series, and with different sampling periods (30, 60, 120 min). The length of the monitoring span did not influence significantly the values of the rhythm parameters only when 15-min or 30-min sampling periods were used. The widths of the 95% confidence limits of amplitude and acrophase were significantly narrower in the 2-day than in the 1-day series. Further lengthening of the monitoring span from 2 to 4 days resulted in a much smaller additional narrowing of the confidence limits. Sampling periods longer than 30 min caused a loss of sensitivity in rhythm detection.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗