Estimation of ocular perfusion: a practical oriented comparison of different methods

BACKGROUND: Ocular haemodynamics play a prominent part in many ocular diseases. This leads to the need to determine ocular perfusion. Several studies reveal advantages of colour Doppler imaging (CDI) in ophthalmologic diagnostics. Little is known about correlation of CDI results with other methods. PATIENTS AND METHODS: N = 56 eyes were examined with CDI, laser Doppler flowmetry (LDF) and Langham-OBF (LOBF). Correlations between the methods were identified by the Spearman correlation coefficient (R). RESULTS: LDF correlated with time average maximum (TAMx) and mean (TAMn) velocity assessed by CDI in the long posterior ciliary artery (TAMx: R = 0.466, p = 0.038, n = 20; TAMn: R = 0.462; p = 0.040, n = 20), but not in the short posterior ciliary artery. LOBF correlated with pulsatility index (PI) and resistive index (RI) of CDI in short (PI: R = 0.514, p = 0.002, n = 35; RI: R = 0.438, p = 0.008, n = 35) and long posterior ciliary arteries (PI: R = 0.436, p = 0.009, n = 35; RI: R = 0.506, p = 0.002, n = 35). DISCUSSION: Methods strengthen each other by partial correlation. CDI allows a more detailed insight into ocular perfusion than the other methods.     

Posterior cerebral artery Wada test: sodium amytal distribution and functional deficits

Inadequate sodium amytal delivery to the posterior hippocampus during the intracarotid Wada test has led to development of selective tests. Our purpose was to show the sodium amytal distribution in the posterior cerebral artery (PCA) Wada test and to relate it to functional deficits during the test. We simultaneously injected 80 mg sodium amytal and 14.8 MBq ^{99 m}Tc-hexamethylpropyleneamine oxime (HMPAO) into the P2-segment of the PCA in 14 patients with temporal lobe epilepsy. To show the skull, we injected 116 MBq ^{99 m}Tc-HDP intravenously. Sodium amytal distribution was determined by high-resolution single-photon emission computed tomography (SPECT). In all patients, HMPAO was distributed throughout the parahippocampal gyrus and hippocampus; it was also seen in the occipital lobe in all cases and in the thalamus in 11. Eleven patients were awake and cooperative; one was slightly uncooperative due to speech comprehension difficulties and perseveration. All patients showed contralateral hemianopia during the test. Four patients had nominal dysphasia for 1–3 min. None developed motor deficits or had permanent neurological deficits. Neurological deficits due to inactivation of extrahippocampal areas thus do not grossly interfere with neuropsychological testing during the test. Received: 16 May 2000 Accepted: 21 November 2000     

Cell surface engineering using glycosylphosphatidylinositol anchored tissue inhibitor of matrix metalloproteinase‐1 stimulates cutaneous wound healing

The balance between matrix metalloproteinases and their endogenous tissue inhibitors (TIMPs) is an important component in effective wound healing. The biologic action of these proteins is linked in part to the stoichiometry of TIMP/matrix metalloproteinases/surface protein interactions. We recently described the effect of a glycosylphosphatidylinositol (GPI) anchored version of TIMP‐1 on dermal fibroblast biology. Here, cell proliferation assays, in vitro wound healing, electrical wound, and impedance measurements were used to characterize effects of TIMP‐1‐GPI treatment on primary human epidermal keratinocytes. TIMP‐1‐GPI stimulated keratinocyte proliferation, as well as mobilization and migration. In parallel, it suppressed the migration and matrix secretion of dermal myofibroblasts, and reduced their secretion of active TGF‐β1. Topical application of TIMP‐1‐GPI in an in vivo excisional wound model increased the rate of wound healing. The agent positively influenced different aspects of wound healing depending on the cell type studied. TIMP‐1‐GPI counters potential negative effects of overactive myofibroblasts and enhances the mobilization and proliferation of keratinocytes essential for effective wound healing. The application of TIMP‐1‐GPI represents a novel and practical clinical solution for facilitating healing of difficult wounds.     

Effects of the selective bisindolylmaleimide protein kinase C inhibitor GF 109203X on P-glycoprotein-mediated multidrug resistance.

Inhibition of protein kinase C (PKC) is discussed as a new approach for overcoming multidrug resistance (MDR) in cancer chemotherapy. For evaluation of this concept we applied the bisindolylmaleimide GF 109203X, which shows a highly selective inhibition of PKC isozymes alpha, beta 1, beta 2, gamma, delta and epsilon in vitro. The efficacy of this compound in modulation of MDR was examined using several P-glycoprotein (P-gp)-overexpressing cell lines including a MDR1-transfected HeLa clone, and was compared with the activities of dexniguldipine-HCI (DNIG) and dexverapamil-HC1 (DVER), both of which essentially act via binding to P-gp. As PKC alpha has been suggested to play a major role in P-gp-mediated MDR, cell lines exhibiting different expression levels of this PKC isozyme were chosen. On crude PKC preparations or in a cellular assay using a cfos(-711)CAT-transfected NIH 3T3 clone, the inhibitory qualities of the bisindolylmaleimide at submicromolar concentrations were demonstrated. At up 1 microM final concentrations of the PKC inhibitor GF 109203X, a concentration at which many PKC isozymes should be blocked substantially, no cytotoxic or MDR-reversing effects whatsoever were seen, as monitored by 72 h tetrazolium-based colorimetric MTT assays or a 90 min rhodamine 123 accumulation assay. Moreover, depletion of PKC alpha by phorbol ester in HeLa-MDR1 transfectants had no influence on rhodamine 123 accumulation after 24 or 48 h. MDR reversal activity of GF 109203X was seen at higher final drug concentrations, however. Remarkably, [3H]vinblastine-sulphate binding competition experiments using P-gp-containing crude membrane preparations demonstrated similar dose dependencies as found for MDR reversion by the three modulators, i.e. decreasing efficacy in the series dexniguldipine-HCl > dexverapamil-HCl > GF 109203X. Similar interaction with the P-gp in the micromolar concentration range was revealed by competition of GF 109203X with photoincorporation of [3H]azidopine into P-gp-containing crude membrane preparations. No significant effect of the PKC inhibitor on MDR1 expression was seen, which was examined by cDNA-PCR. Thus, the bisindolylmaleimide GF 109203X probably influences MDR mostly via direct binding to P-gp. Our work identifies the bisindolylmaleimide GF 109203X as a new type of drug interacting with P-gp directly, but does not support the concept of a major contribution of PKC to a P-gp-associated MDR, at least using the particular cellular model systems and the selective, albeit general, PKC inhibitor GF 109203X.     

First clinical experience with beta-trace protein (prostaglandin D synthase) as a marker for perilymphatic fistula

A diagnosis of perilymphatic fistula is still controversial. Recently, a case report indicated that beta-trace protein (prostaglandin D synthase) might be a potential marker for perilymphatic fluid. In this multicentre clinical case series study beta-trace protein was used as a marker for perilymphatic fluid fistula. Fifteen fluid samples were collected during diagnostic tympanoscopy. In addition, five samples were collected from patients with tympanic membrane perforation for use as as negative controls. Samples were obtained using precision glass capillaries and were analysed for beta-trace protein using laser nephelometry. The diagnosis of perilymphatic fistula was defined by the patient's history, the audiological and vestibular investigation and the findings at tympanoscopy. The cut-off level of beta-trace protein for perilymph-positive samples was chosen at 1.11 mg/l. The sensitivity and specificity were calculated using a 2 x 2 contingency table. There was no false positive result, but in two cases a false negative result was found. The specificity was 1 and the sensitivity was 0.81. The material of this first clinical study is small owing to the rarity of patients undergoing diagnostic tympanoscopy for perilymphatic fluid fistula. However, according to these preliminary results beta-trace protein might be a promising marker in the diagnosis of perilymphatic fluid fistulas.     

PYY3-36 reinforces insulin action on glucose disposal in mice fed a high-fat diet

Peptide YY(3-36) (PYY(3-36)) is released by the gut in response to nutrient ingestion. It modulates the activities of orexigenic neuropeptide Y (NPY) neurons and anorexigenic proopiomelanocortin (POMC) neurons in the hypothalamus to inhibit food intake. Because both NPY and POMC have also been shown to impact insulin action, we wondered whether PYY(3-36) could improve insulin sensitivity. To address this question, we examined the acute effect of intravenous PYY(3-36) on glucose and free fatty acid (FFA) flux during a hyperinsulinemic-euglycemic clamp in mice maintained on a high-fat diet for 2 weeks before the experiment. We also evaluated the effects of PYY(3-36) infusion on glucose uptake in muscle and adipose tissue in this experimental context. Under basal conditions, none of the metabolic parameters were affected by PYY(3-36). Under hyperinsulinemic conditions, glucose disposal was significantly increased in PYY(3-36)-infused compared with vehicle-infused mice (103.8 +/- 10.9 vs. 76.1 +/- 11.4 micromol.min(-1).kg(-1), respectively; P = 0.001). Accordingly, glucose uptake in muscle and adipose tissue was greater in PYY(3-36)-treated animals, although the difference with controls did not reach statistical significance in adipose tissue (muscle: 2.1 +/- 0.5 vs. 1.5 +/- 0.5 micromol/g tissue, P = 0.049; adipose tissue: 0.8 +/- 0.4 vs. 0.4 +/- 0.3 micromol/g tissue, P = 0.08). In contrast, PYY(3-36) did not impact insulin action on endogenous glucose production or FFA metabolism. These data indicate that PYY(3-36) reinforces insulin action on glucose disposal in mice fed a high-fat diet, through a mechanism that is independent of food intake and body weight. In contrast, it leaves glucose production and lipid flux largely unaffected in this experimental context.     

Allergies in adults

Only few epidemiological studies have assessed allergic diseases in adults. In a follow-up study of the MONICA survey S3 (1994/95), which was performed 1997-1999, a total of 1,537 persons were interviewed and tested by skin prick and patch test. Furthermore data of the MONICA survey (RAST, cholesterol, food diaries) could be used. Within survey S4 (1999/2001) a total of 4,261 subjects were interviewed concerning their personal history of atopic diseases and the corresponding history of their partners. In survey S3 the prevalence of allergic sensitisation was 20.5 % for persons without formal graduation from school and 48.1 % for those with a university degree. 20.8 % reported a hypersensitivity to food and about one quarter exhibited a positive reaction in skin prick test. Atopic eczema and hay fever increased over quartiles of HDL cholesterol. Similar, allergic sensitisation (RAST) increased over quartiles of uptake of unsaturated fatty acids in men. 40 % of those who were patch tested exhibited a positive reaction, with perfume mix, nickel, thimerosal and balsam of Peru being the most prominent allergens. Inhabitants of the City of Augsburg were sensitised more often (34.0 % overall, 23.9 % pollen) than inhabitants of villages with (29.4 %, 17.0 %). Full time farmers were sensitised less frequently (22.0 %, 8.4 %). In survey S4 the lifetime prevalence of atopic diseases diagnosed by doctors was 5.1 % for atopic eczema, 6.1 % for asthma and 13.7 % for hay fever. Subjects who lived together with a partner who suffered from hay fever were affected in 19.6 % whereas 13.1 % had hay fever when the partner was not affected. Future studies will offer an unique opportunity to analyse the incidence and remission of manifestations of atopy in adults.     

Radioanalytical data interpretation when the ratio reading/median is lognormally distributed

The purpose of this paper is to assist those who might be confronted by non-normal and non-homoscedastic error distributions representable by continuous probability density functions. Methods are presented to demonstrate how mathematical algorithms can be developed to obtain a "best fit" calibration line and how uncertainty ranges in interpretations of unknowns can be obtained from the calibration. The data used to demonstrate these methods were obtained from Brookhaven National Laboratory fission track analysis data for plutonium in urine. Examination of the variability in the fission track analysis data, during the period of time that the demonstration data were collected, revealed that the deviations from the mean were neither normal nor lognormal, but the ratios of tracks divided by the median at each plutonium level were lognormally distributed. Consequently, the differences between the logarithms of observed tracks and the median were normally distributed. The new "best fit" line was obtained by minimizing a reduced chi-square statistic made up of the squared differences in logarithms, divided by the variance in logarithms and degrees of freedom. Thus, to detect a worker urine sample to be above the 58-person "control" population 95 percentile [about 3.2 microBq (85 aCi)] at the 95% probability level (0.05 Type H error) would now require an average of about 11 microBq (300 aCi) per sample, compared to 5 microBq per sample (132 aCi per sample) in a previous paper. This paper presents the algorithms used to obtain the new calibration line and the uncertainty distributions of interpretations at various analyte levels. The importance of maintaining process control over the statistical interpretation of bioassay data as well as for the radiochemical procedures for achieving the lowest feasible level of detection is demonstrated.