Long-term immunogenicity of an inactivated virosome hepatitis A vaccine

The aim of this study was to predict the long-term protection induced after immunisation with inactivated, aluminium-free virosome hepatitis A vaccine. The study population consisted of adult volunteers enrolled in four different clinical trials. Lower 95% confidence interval limits and seroconversion rate were calculated by using a linear mixed model to estimate the persistence of serum antibodies over time. To assess the robustness of the mathematical model, several sensitivity analyses were performed with more conservative protective threshold (20 mIU/ml vs. 10 mIU/ml), higher yearly decline rate, and exclusion of volunteers who had increasing titres over time. Based on 190 volunteers with at least two valid assessments of titres from year 3 onward, the median duration of protection was 55.5 years, with a lower limit of the 95% CI of 48.7 years. Duration below 25.3 years was predicted for only 5% of the subjects. Women tended to have higher titres to start with, but their rate of decline was higher, resulting in similar duration of protection overall. The use of a more conservative threshold, higher yearly decline rate, and exclusion of volunteers with increasing titres over time did not affect these results. According to this model, 95% of the volunteers should have anti-HAV titres above the minimum protective threshold for 20 years or more following immunisation with two doses of this aluminium-free vaccine.

Clustering of CD40 ligand is required to form a functional contact with CD40

Receptor clustering is a key event in the initiation of signaling by many types of receptor molecules. Here, we provide evidence for the novel concept that clustering of a ligand is a prerequisite for clustering of the cognate receptor. We show that clustering of the CD40 receptor depends on reciprocal clustering of the CD40 ligand (gp39, CD154). Clustering of the CD40 ligand is mediated by an association of the ligand with p53, a translocation of acid sphingomyelinase (ASM) to the cell membrane, an activation of the ASM, and a formation of ceramide. Ceramide appears to modify preexisting sphingolipid-rich membrane microdomains to fuse and form ceramide-enriched signaling platforms that serve to cluster CD40 ligand. Genetic deficiency of p53 or ASM or disruption of ceramide-enriched membrane domains prevents clustering of CD40 ligand. The functional significance of CD40 ligand clustering is indicated by the finding that clustering of CD40 on B lymphocytes upon co-incubation with CD40 ligand-expressing T cells depends on clustering of the CD40 ligand and is abrogated by inhibition of CD40 ligand clustering.

Actinomycin D-induced apoptosis involves the potassium channel Kv1.3

Several cytostatic agents are known to induce apoptosis in T-leukemic cells. Although a variety of studies show the central role of apoptosis in cytostatic drug-induced cell death, many molecular details require definition. Here, we demonstrate that cells genetically deficient for the potassium channel Kv1.3 are resistant to apoptosis initiated by the cytostatic drug actinomycin D. Retransfection of Kv1.3 restores sensitivity of the cells to actinomycin D. Cells lacking Kv1.3 fail to respond to actinomycin D with DNA fragmentation, release of cytochrome c, and loss of mitochondrial membrane potential (Delta Psi(m)), while cells functionally expressing Kv1.3 rapidly undergo those changes indicative for apoptosis. The data indicate a central role of the ion channel Kv1.3 in actinomycin D-triggered apoptosis.

Ceramide-rich membrane rafts mediate CD40 clustering

Many receptor systems use receptor clustering for transmembrane signaling. In this study, we show that acid sphingomyelinase (ASM) is essential for the clustering of CD40. Stimulation of lymphocytes via CD40 ligation results in ASM translocation from intracellular stores, most likely vesicles, into distinct membrane domains on the extracellular surface of the plasma membrane. Surface ASM initiates a release of extracellularly oriented ceramide, which in turn mediates CD40 clustering in sphingolipid-rich membrane domains. ASM, ceramide, and CD40 colocalize in the cap-like structure of stimulated cells. Deficiency of ASM, destruction of sphingolipid-rich rafts, or neutralization of surface ceramide prevents CD40 clustering and CD40-initiated cell signaling. These findings indicate that the ASM-mediated release of ceramide and/or metabolites of ceramide regulate clustering of CD40, which seems to be a prerequisite for cellular activation via CD40.

Saquinavir and ritonavir pharmacokinetics following combined ritonavir and saquinavir (soft gelatin capsules) administration

AIMS

To investigate the influence of combined ritonavir (RTV) and saquinavir (soft-gelatin capsule formulation; SQV) on systemic exposure to SQV with a view to optimizing the dosing regimen of combined RTV and SQV antiretroviral therapy.

METHODS

In this open labelled, randomized, parallel group study, SQV and RTV were administered twice daily for 14 days to groups of eight healthy subjects. The two antiretrovirals were either administered alone (800 mg SQV, regimen A, and 400 mg RTV, B) or in combination at various dose levels (RTV : SQV: 400 : 400 mg, C; 300 : 600 mg, D; 200 : 800 mg, E; 300 : 800 mg, F; 400 : 800 mg, G; and 400 : 600 mg, H). Pharmacokinetic parameters of saquinavir and ritonavir were determined and adverse events, vital signs, and clinical laboratory variables recorded.

RESULTS

RTV substantially increased the plasma concentration of saquinavir for all dose combinations, compared with SQV alone. Based on the primary statistical analysis there was an overall 17-, 22-, and 23-fold increase in saquinavir AUC(0,24 h) on day 14 with regimens E, F, and G, respectively (with confidence intervals of 10-30, 13-37, and 13-39). The lowest combination dose of RTV (200 : 800 mg; E) significantly increased the saquinavir AUC(0,24 h) from below 5 to 57 microg ml(-1) h, which was higher than the exposure obtained with the 400 : 400 mg twice daily regimen (i.e. 36 microg ml(-1) h). RTV also reduced intersubject variability in AUC(0,24 h) for saquinavir from 105% to 32-68%, and C(max)(0,24 h) from 124% to 30-49%. In contrast, SQV showed no clinically significant effect on the pharmacokinetics of ritonavir. The combination regimens were well tolerated, with the least number of adverse events recorded for the 200 : 800 mg (RTV : SQV) combination regimen.

CONCLUSIONS

RTV significantly increases saquinavir exposure as a consequence of inhibiting SQV metabolism and possibly P-glycoprotein efflux. Pharmacokinetic and safety profiles obtained in the current study indicate that the use of a combination with a lower dose of RTV and a higher dose of SQV than the 400 : 400 mg combination frequently used in clinical practice should be further explored.

Expression of cell volume-regulated kinase h-sgk in pancreatic tissue

Transcript levels of the human serine/threonine kinase h-sgk have been found to be highest in pancreas. In the present study, localization and regulation of h-sgk transcription in pancreatic tissue were elucidated. As was apparent from radioactive in situ hybridization, most pancreatic acinar cells expressed high levels of h-sgk mRNA. h-sgk mRNA-positive cells were also found in ductal epithelia but not in pancreatic islets. In biopsy specimens from patients with pancreatitis, h-sgk mRNA levels were decreased in acinar cells but abundant in numerous mononuclear interstitial cells within areas of pancreatic necrosis and fibrosis. As shown by Northern blotting, h-sgk transcription in DAN-G pancreatic tumor cells is upregulated by osmotic cell shrinkage, serum, phorbol esters (phorbol 12,13-didecanoate), and Ca(2+) ionophore A-23187 and decreased by staurosporine and cAMP. In conclusion, h-sgk transcription is regulated not only by cell volume but also by serum, protein kinase C stimulation, cAMP, and increase of intracellular Ca(2+) activity. The kinase may participate not only in normal function of exocrine pancreas but also in fibrosing pancreatitis.

Inhibition of Jurkat-T-lymphocyte Na+/H+-exchanger by CD95(Fas/Apo-1)-receptor stimulation

Mitogenic factors are known to stimulate the Na+/H+-exchanger (NHE), leading to cytosolic alkalinization and/or cell swelling. Conversely, a hallmark of apoptosis is cell shrinkage and CD95-induced apoptosis has been reported to be paralleled by cytosolic acidification. To assess whether the CD95-receptor regulates NHE activity in Jurkat T-lymphocytes, we performed conventional BCECF fluorescence measurements and SNARF flow cytometric analysis (FACS). The recoveries from acidifications following application of butyrate or a NH3 pulse were both abolished by a specific NHE-inhibitor, HOE694, indicating that they fully depend on NHE activity. Thus they were taken as a measure of NHE activity. CD95-receptor stimulation caused a cytosolic acidification and blunted the recovery from acidification following application of butyrate or a NH3 pulse. Moreover, the NHE-dependent alkalinization following osmotic cell shrinkage was almost abolished by CD95-receptor stimulation. As apparent from the effect of osmotic cell shrinkage, inhibition of the NHE by CD95-receptor stimulation was absent in Lck56-deficient J-CaM1.6 cells and restored by retransfection of J-CaM1.6-cells with Lck56. CD95-receptor stimulation led within 4 h to a decrease of cellular ATP which could contribute to NHE inhibition. Treatment of Jurkat cells with the NHE inhibitor HOE694 accelerated CD95-induced DNA fragmentation. In conclusion, CD95-receptor stimulation inhibits NHE activity through a mechanism that depends directly or indirectly on the activation of the Src-like kinase Lck56. This effect contributes to CD95-induced cytosolic acidification, DNA fragmentation and cell shrinkage.

Acid sphingomyelinase is involved in CEACAM receptor-mediated phagocytosis of Neisseria gonorrhoeae

The interaction with human phagocytes is a hallmark of symptomatic Neisseria gonorrhoeae infections. Gonococcal outer membrane proteins of the Opa family induce the opsonin-independent uptake of the bacteria that relies on CEACAM receptors and an active signaling machinery of the phagocyte. Here, we show that CEACAM receptor-mediated phagocytosis of Opa(52)-expressing N. gonorrhoeae into human cells results in a rapid activation of the acid sphingomyelinase. Inhibition of this enzyme by imipramine or SR33557 abolishes opsonin-independent internalization without affecting bacterial adherence. Reconstitution of ceramide, the product of acid sphingomyelinase activity, in imipramine- or SR33557-treated cells restores internalization of the bacteria. Furthermore, we demonstrate that CEACAM receptor-initiated stimulation of other signalling molecules, in particular Src-like tyrosine kinases and Jun N-terminal kinases, requires acid sphingomyelinase. These studies provide evidence for a crucial role of the acid sphingomyelinase for CEACAM receptor-initiated signalling events and internalization of Opa(52)-expressing N. gonorrhoeae into human neutrophils.

Filial imprinting in domestic chicks is associated with spine pruning in the associative area, dorsocaudal neostriatum

Juvenile emotionally modulated learning events are fundamental for the normal development of socio-emotional competence and intellectual capabilities. Filial imprinting in the domestic chick provides a suitable model to investigate the neural mechanisms underlying such juvenile learning events. The forebrain area dorsocaudal neostriatum (Ndc), a multimodal integration area and presumed equivalent to mammalian parietotemporal association cortices, has been shown to be critically involved in this learning process. We investigated whether filial imprinting is associated with changes of synaptic connectivity in the Ndc. Quantitative measurements of spine densities of a large neuron type in the Ndc revealed a massive pruning of spine synapses after filial imprinting. Compared with 7-day-old naive control chicks, imprinted chicks displayed significantly lower spine frequencies on all dendritic segments. Since the average length of the dendritic segments did not change during imprinting, these results can be interpreted as a reduction of the absolute number of spine synapses on this neuron type. In a control region, the primary sensory forebrain area ectostriatum, spine density and dendritic length remained unchanged. These results indicate that synaptic pruning may represent a mechanism of selective synaptic reorganization in higher associative forebrain areas as a fundamental feature of juvenile learning events.

Prevention of radiocontrast-media-induced nephropathy in patients with pre-existing renal insufficiency by hydration in combination with the adenosine antagonist theophylline

BACKGROUND

Radiographic contrast media (CM) application causes a decline in renal function, especially in patients with pre-existing renal dysfunction. In addition to hydration, several vasodilating substances have been evaluated for their ability to prevent renal damage after CM application. In a prospective, double-blind, placebo-controlled study we investigated the effect of the oral administration of theophylline, an adenosine receptor antagonist, on changes in renal haemodynamics and tubular injury induced by CM in well-hydrated patients with mild-to-moderate renal insufficiency.

METHODS

We studied 80 patients with pre-existing chronic renal insufficiency (creatinine > 1.5 mg/dl) who received more than 100 ml iopromide. Hydration (either oral or intravenous) started at least 24 h before and lasted until 24 h after CM application. In addition, patients were randomly assigned to receive either theophylline (810 mg daily) or placebo. Serum creatinine and creatinine clearance were measured before and for 3 days after CM application. Urine was collected to measure N-acetyl-beta-glucosaminidase (NAG) enzymuria for the same period. Sixty-four patients completed the entire study protocol (theophylline, n = 35 and placebo, n = 29).

RESULTS

During the study period serum creatinine concentration and creatinine clearance did not change significantly in either group. Acute renal failure (increase of serum creatinine of at least 0.5 mg/dl) could be observed in two patients from the theophylline group (5.7%) and one from the placebo group (3.4%). The increase in NAG excretion reached statistical significance (P < 0.05) in the placebo group on days 2 and 3 after CM application.

CONCLUSIONS

Our results indicate a role for adenosine in CM-induced tubulotoxicity. However, the glomerular filtration rate is preserved by hydration alone in these patients. The application of theophylline did not bring an additional benefit. The use of adenosine antagonists may be beneficial in patients where sufficient hydration may be impossible or in patients with a concomitant decrease in renal blood flow (e.g. congestive heart failure).

Blockade of N-methyl-D-aspartate receptor activation suppresses learning-induced synaptic elimination

Auditory filial imprinting in the domestic chicken is accompanied by a dramatic loss of spine synapses in two higher associative forebrain areas, the mediorostral neostriatum/hyperstriatum ventrale (MNH) and the dorsocaudal neostriatum (Ndc). The cellular mechanisms that underlie this learning-induced synaptic reorganization are unclear. We found that local pharmacological blockade of N-methyl-D-aspartate (NMDA) receptors in the MNH, a manipulation that has been shown previously to impair auditory imprinting, suppresses the learning-induced spine reduction in this region. Chicks treated with the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid (APV) during the behavioral training for imprinting (postnatal day 0-2) displayed similar spine frequencies at postnatal day 7 as naive control animals, which, in both groups, were significantly higher than in imprinted animals. Because the average dendritic length did not differ between the experimental groups, the reduced spine frequency can be interpreted as a reduction of the total number of spine synapses per neuron. In the Ndc, which is reciprocally connected with the MNH and not directly influenced by the injected drug, learning-induced spine elimination was partly suppressed. Spine frequencies of the APV-treated, behaviorally trained but nonimprinted animals were higher than in the imprinted animals but lower than in the naive animals. These results provide evidence that NMDA receptor activation is required for the learning-induced selective reduction of spine synapses, which may serve as a mechanism of information storage specific for juvenile emotional learning events.

A comparative study of CD34+ cells, CD34+ subsets, colony forming cells and cobblestone area forming cells in cord blood and bone marrow allografts

Cord blood (CB) has become an alternative source of hematopoietic progenitor cells (HPCs) for allogeneic transplantation. We have developed a new efficient protocol for CB collection. Using this method an average of 17.7 x 10(8) [range (6.8-29.6) x 10(8), n = 13] total nucleated cells (TNCs) were harvested. Based on recent Eurocord data, which have shown safe engraftment using a threshold dose of 0.37 x 10(8) CB TNCs/kg body weight (BW), we calculated that six out of thirteen CB grafts collected by this method were sufficient to engraft adults. The CB derived CD34+ population contained two-fold higher numbers of committed HPCs (CFU-GM, BFU-E) and six-fold higher numbers of pluripotent HPCs [CD34+/CD38- cells, wk 5 and wk 8 cobblestone area forming cells (CAFCs)] than the CD34+ population of BM. Extrapolation revealed that BM grafts providing the threshold dose for allogeneic transplantation of 2 x 10(8) TNCs/kg BW contained nearly 3 times more pluripotent HPCs than CB grafts providing the Eurocord threshold dose. The assessment of CD34+/CD38(-) cell numbers in CB grafts was highly reproducible and correlated well with the in vitro performance of pluripotent HPCs, i.e. numbers of CAFCs. We conclude that CB grafts providing high numbers of TNCs have the potential to engraft adults and that the enumeration of pluripotent HPCs by flow cytometry may be a useful tool to define the ultimate threshold dose for CB transplantation.

The dorsocaudal neostriatum of the domestic chick: a structure serving higher associative functions

The dorsocaudal neostriatal (dNC) complex consists of at least three functionally distinct subregions and is part of an 'imprinting' pathway, which interconnects several forebrain regions that are known to be involved in juvenile learning. Based on its anatomical features, at least one subregion of the dNC complex, the neostriatum dorsocaudale (Ndc) may be considered as the equivalent of the mammalian polysensory association cortices. Several lines of evidence point to a role for this forebrain region in learning and memory formation. After auditory or visual imprinting changes of stimulus-evoked metabolic activities and of synaptic densities have been measured in the Ndc. Pharmacological behavioral studies revealed that the activation of NMDA receptors plays a critical role during this learning process and that NMDA receptor activation is required for the associated metabolic and synaptic changes. In addition to glutamatergic afferents, anatomical studies revealed a massive input from monoaminergic and peptidergic pathways into the dNC complex, suggesting a modulatory role for these systems during imprinting. The results presented here together with data from other avian species support the view that the dNc complex, and in particular the Ndc, plays an important role in juvenile and adult learning.

Toward prediction of physiological state signals in sleep apnea

A recurrent connectionist model is described to predict dynamic respiratory state in the apneic sleeping patient. The time-domain model of nonlinear time-lagged interactions between heart rate, respiration, and oxygen saturation was developed to implicitly embed the dynamics of the respiration and cardiovascular control systems. Multiple future time scales were enforced on the network during training to explore the limits of the prediction horizon and produce a global representation of dynamic state trajectory. Predicted apneic respiration state results are presented in terms of invariant geometric statistics (largest Lyapunov exponent lambda L and correlation dimension Dc). The lambda L prediction error was 13%, while Dc error was within 9% of the true time series value. The magnitude of these errors may fall within experimental noise levels. This methodology may eventually be useful in dynamic control of continuous positive airway pressure (CPAP) therapy devices, and may lead to increased patient compliance with this therapy.

Differential emotional experience leads to pruning of dendritic spines in the forebrain of domestic chicks

Auditory filial imprinting induces quantitative changes of synaptic density in the forebrain area mediorostral neostriatum/hyperstriatum ventrale of the domestic chick. The aim of the present study was to examine the time window and the extent and quality of experience that is required for the induction of these synaptic changes. We found that a brief (30 min) experience with the imprinting situation (tone stimulus + mother surrogate) is sufficient to induce spine elimination, which is detectable on postnatal day 7, but not 80 min after the presentation of the imprinting stimuli. This synaptic reorganization requires the association of the acoustic imprinting tone with an emotional reward (mother surrogate); acoustic stimulation alone does not lead to detectable synaptic changes. The results of the present study provide further evidence that juvenile emotional learning events, such as filial imprinting, lead to a selective synaptic reorganization.

Role of the dorso-caudal neostriatum in filial imprinting of the domestic chick: a pharmacological and autoradiographical approach focused on the involvement of NMDA-receptors

Newly hatched domestic chicks were either acoustically imprinted on 400 Hz tone pulses or visually imprinted on a rotating red light. Compared to naive control animals, both groups of imprinted chicks expressed significantly enhanced stimulus evoked 2-fluoro-2-deoxyglucose (2-FDG) uptake in circumscribed areas of the dorso-caudal neostriatum (Ndc). This enhanced excitability after imprinting seems not to be related to changes of NMDA-receptor densities as measured by quantitative receptor autoradiography. However, pharmacological blockade of NMDA-receptors in the dorso-caudal neostriatum leads to a marked suppression of stimulus-evoked 2-FDG uptake in the dorso-caudal neostriatum and also in the interconnected imprinting relevant forebrain area, medio-rostral neostriatum/hyperstriatum ventrale (MNH). Furthermore, chicks which received bilateral Ndc injections of the competitive NMDA antagonist DL-2-amino-5-phosphono valeric acid (APV) during the imprinting experiments showed a dose-dependent decrease of imprinting success compared to vehicle-injected controls. These results indicate that the dorso-caudal neostriatum may represent a polysensory associative brain region in which visual and acoustic features of imprinting objects may be integrated. The activation in this area evoked by the imprinting stimulus during and after imprinting is critically dependent on NMDA-receptor activation, which appears to be required for this learning process.

Influence of the N-methyl-D-aspartate receptor antagonist DL-2-amino-5-phosphonovaleric acid on auditory filial imprinting in the domestic chick

Newly hatched domestic chicks were injected uni- or bilaterally into the imprinting relevant forebrain region mediostral neostriatum/ hyperstriatum ventrale (MNH) with different concentrations (1, 3, 12.5, 50 nmol) of the competitive NMDA antagonist DL-5-amino-5- phosphonovaleric acid (APV) prior to exposure to the imprinting stimulus (400-Hz tone pulses). In both APV-injected experimental groups there was a dose-dependent decrease of imprinting rates compared to that seen in controls, suggesting an APV-induced blockade of the learning process. In order to find out how the injected APV interferes with the stimulus-evoked enhanced metabolic activity in imprinting-relevant brain regions and to gain information about the spatial extent of its physiological effect, 2-fluorodeoxyglucose (2-FDG) experiments were performed. Chronically APV-treated chicks which failed in the imprinting tests showed similarly low 2-FDG uptake in imprinting relevant areas as naive untreated controls, further suggesting that no learning process has occurred in these animals. In imprinted chicks acute APV injections into the MNH led to a suppression of the stimulus-evoked 2-FDG uptake in this region. This pharmacologically induced reduction extended beyond the MNH region to adjacent regions. Furthermore, unilateral injections into the MNH always resulted in a bilateral reduction of 2-FDG uptake in this area. The results suggest that NMDA-mediated mechanisms in restricted telecephalic areas such as the MNH play a crucial role in the process of auditory filial imprinting.

Comparative pharmacodynamics of Ro 41-3696, a new hypnotic, and zolpidem after night-time administration to healthy subjects

In a double-blind, six-way crossover study the effects on psychomotor performance and memory of single doses of Ro 41-3696 (1, 3, 5 and 10 mg), a novel non-benzodiazepine partial agonist at the benzodiazepine receptor, zolpidem (10 mg) and placebo were compared after night-time administration to 12 healthy young male subjects. Psychomotor performance tests (tracking and attention as part of a standardized task battery) were conducted just before and at 1.5 and 8 h after drug intake. The memory test consisted of the recall of a list of 15 words at 8 h after drug intake which had been learned at 1.5 h after intake. At 1.5 h after drug intake 10 mg zolpidem induced markedly larger psychomotor effects than any dose of Ro 41-3696. The effects of 5 and 10 mg Ro 41-3696 and zolpidem were significantly greater than those of placebo (P < 0.05). The following morning, 8 h after drug intake, the slight residual effects of 5 and 10 mg Ro 41-3696 were statistically significantly greater than placebo, whereas zolpidem effects did not differ from placebo. The results of the memory test showed that learning as well as recall were most clearly impaired by zolpidem. An influence of Ro 41-3696 on these variables was not observed for doses up to 5 mg. In conclusion, Ro 41-3696 at all doses tested induced less effects on psychomotor performance and memory than 10 mg zolpidem at 1.5 h after intake. However, the effects of Ro 41-3696 appeared to be of longer duration.

Gonadotropin-releasing hormone agonist suppression of ovarian tumorigenesis in mice of the Wx/Wv genotype

Although many investigations have shown a correlation between elevated gonadotropin levels and ovarian tumors (the gonadotropin theory), the ovarian response to a specific suppression of the gonadotropins has not been elucidated. The ovaries of (C57BL/6J x C3H/HeJ)F1-Wx/Wv mice, which contain 1% of the normal oocyte count at birth, rapidly lose the follicular apparatus and develop a 100% incidence of bilateral complex tubular adenomas from the surface germinal epithelium, which is also the origin of 90% of human ovarian carcinomas. Plasma levels of LH and FSH are known to rise fourfold during the period of tumorigenesis. We compared tumor development in Wx/Wv mice after either injecting a GnRH agonist (3.6 mg slow-release goserelin depot, Zoladex Depot) or administering a sham injection every 28 days from the age of 7 days up to 245 days. All 15 Wx/Wv mice that received sham injections developed bilateral ovarian tubular adenomas from the surface germinal epithelium. In none of the 11 mice receiving the GnRH agonist was any tumor found (p < 0.00005), and a significant suppression of the gonadotropins was demonstrated (p < 0.00005).

Ovarian carcinoma serum markers and ovarian steroid activity--is there a link in ovarian cancer? A correlation of inhibin, tetranectin and CA-125 to ovarian activity and the gonadotropin levels

In a previous study, we have demonstrated that inhibin-production may be associated with improved survival and, also, that tetranectin (TN) is a valuable prognostic marker in ovarian epithelial cancer. We investigated the possible correlation between inhibin, tetranectin, CA-125, ovarian steroid activity and the gonadotropin levels. Preoperative serum levels of the tumor markers inhibin, tetranectin (TN) and CA-125 were measured and related to ovarian steroid function and the pituitary-gonadal axis (gonadotropin levels) in 28 postmenopausal ovarian cancer patients. The following median levels and 95% confidence limits were demonstrated for the tumor markers: Inhibin 0.4 U/l (0.2-0.9), TN 8.9 mg/l (6.8-9.2), CA-125 160 kU/l (75-687). A significant inverse correlation was demonstrated between inhibin and the gonadotropins. The Spearman correlation coefficients showed a highly significant correlation of inhibin with the examined ovarian steroid hormones except DHEAS which also has a suprarenal component. This indicates a synthesis of inhibin and the steroid hormones from the same cell compartment as known from the normal ovary and an apparently intact negative feed back mechanism. Inhibin may be produced in the normal ovary as a defense mechanism against an elevated gonadotropin level and inhibin acts by lowering the gonadotropins or by altering their biological activity. Elevated values of the tumor markers TN and CA-125 due to gonadotropin stimulation could not be demonstrated but a significant inverse correlation between TN and CA-125 was confirmed.

EFFECT OF STOKES’ LAW SETTLING ON MEASURING OIL DISPERSION EFFECTIVENESS

Industry laboratory tests to measure dispersion effectiveness for oil spills on water measure only the volume percentage of oil dispersed and not the dispersed particle size. The effect of particle size on settling behavior is particularly pronounced in tests that use long settling times to superimpose a dispersion stability criterion on the effectiveness rating.

The authors have studied the effect of settling time on the volume cumulative particle size distribution measured by the Coulter Multisizer II. Using Stokes’ law settling to analyze the results, we have demonstrated the effects of settling flask geometry and sample volume on measured effectiveness. These arbitrary test variables control the settling path height and vary markedly from test to test. The intrinsic variables that control settling vs time—initial particle size distribution, aqueous viscosity, and aqueous and oil densities—are functions of aqueous, oil, and dispersant compositions; temperature; and dispersion energy.

The author's analysis shows that the effect of settling variables is to cut off the initial cumulative particle size distribution above a certain particle size, thereby fixing measured effectiveness. Stokes’ law provides a measure of this cutoff size. Experimental data have been developed to support this theoretical analysis. This analysis points to the variables that must be considered with different laboratory tests to rank dispersants when settling is part of the test procedure. Even with a single test, ranking may change with settling time given an initially large fraction of large particles and a sufficiently large difference between the densities of water and oil.

DISPERSION AND BIODEGRADATION OF OIL SPILLS ON WATER

Published literature indicates that oil spill dispersion by chemical dispersants will enhance biodegradation because of the increase in interfacial area. However, some of the literature is contradictory concerning whether the use of surfactants will enhance or temporarily inhibit biodegradation, suggesting that more than one mechanism is at work.

We set out to study the correlation between the area of dispersed oil droplets and the rate and extent of microbial oil degradation using sorbitan surfactants. We varied the surfactant blend hydrophile-lipophile balance (HLB) and treat level in a statistically designed experiment. Both dispersed area and percent oil degraded at a given time were shown to depend on surfactant HLB and treat level, but to different degrees. The difference was accounted for by demonstrating that percent oil degraded depended on both dispersed area and percent sorbitan in the dispersant treat. The quantitative finding that both dispersed area and surfactant chemistry control microbial growth and oil biodegradation explains the apparent contradiction that some good dispersants enhance, while others temporarily inhibit, degradation. Corexit 9500 dispersant was observed to have a positive influence on biodegradation of oil on water.

Time dependency of the antihypertensive efficacy of the new renin inhibitor Ro 42-5892

The objective of this study was to assess the antihypertensive efficacy of the new renin inhibitor Ro 42-5892 in patients with essential hypertension treated with 100 mg once daily orally. This was a double-blind, placebo-controlled, parallel group trial. After three weeks of wash-out and one week of single-blind placebo run-in periods, 25 patients with mild to moderate essential hypertension (sitting DBP between 95 and 114 mmHg) were randomised to receive either placebo (n = 12) or 100 mg of Ro 42-5892 (n = 13) once daily for eight days. On the eighth day, four hours after the oral administration, patients were randomised to receive intravenously either placebo or 10 mg of Ro 42-5892. BP and heart rate were measured repeatedly (hourly for eight hours and at the 24th hour post-dose) on the first and last days of active treatment. Compared with the placebo group, a slight decrease in sitting DBP was observed after the first dose in the Ro 42-5892 group. The decrease in sitting DBP reached significant levels only at six to eight hours post-dosing. In contrast, on the last day of active treatment, a larger, faster and longer decrease in sitting DBP was observed in the Ro 42-5892 group. Thus, the peak effect (-8.9 +/- 1.9 vs. -2.9 +/- 1.3 mmHg, P < 0.01) was reached 1.5 hours post-dosing and the trough effect (24 hours post-dosing) was slightly but significantly lower when compared with the placebo group (-3.0 +/- 1.0 vs -0.3 +/- 0.8 mmHg, P < 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Hormonal factors and prognosis in epithelial ovarian cancer: a multivariate analysis

When a significantly lower follicle stimulating hormone (FSH) level was found in patients with epithelial ovarian carcinoma, it was decided to analyze the influence of hormonal factors on prognosis. Thirteen factors were tested for prognostic significance in 35 women with epithelial ovarian carcinoma. Age, FIGO-stage, histopathological grade, residual tumor, treatment, gonadotrophins and steroid hormones were tested. By univariate log-rank testing a significantly shorter survival time was found for patients with ascending FIGO-stage, residual tumor mass, estradiol < 0.10 nmol/l, progesterone < 2.0 nmol/l and DHEAS < 1300 nmol/l. In the Cox model the independently significant prognostic factors found were residual tumor mass (P < 0.001) with a risk estimate of 2.65, progesterone (P < 0.05) with a risk estimate of 0.29 for a progesterone level > 2.0 nmol/l and total testosterone (P < 0.03) with a risk estimate of 0.29 for a total testosterone level > 1.15 nmol/l. The present findings, together with the assumption that an elevated gonadotrophin level may induce ovarian tumor growth (the gonadotrophin theory), earlier findings of estrogen and progesterone receptors in human ovarian cancer, and the in vitro demonstration of gonadotrophin-growth-stimulation of human malignant epithelial tumors, justify a thorough investigation of the interaction between steroid hormones and receptors, gonadotrophins, tumor bulk and survival in future research protocols.

Effects of an orally active renin inhibitor, Ro 42-5892, in patients with essential hypertension

Ro 42-5892 (Ro) is a new renin inhibitor that has been shown to be an orally effective compound in primates and in the first exploratory studies in humans. However, no firm conclusions could be drawn from the human trials and therefore the present study was designed to evaluate the antihypertensive efficacy of the compound in a double-blind, placebo-controlled trial. After a 3 week wash-out period and a 1 week single-blind placebo period, 24 patients were randomized to receive once daily orally either placebo or 600 mg Ro 42-5892 (N = 12/group) for 8 days. On the last day of treatment, an intravenous infusion of placebo or 100 mg Ro was given in a double-blind fashion, 4 h after the oral administration. Blood pressure (BP), heart rate (HR), plasma renin activity (PRA), immunoreactive renin (IRR), and plasma Ro levels were measured repeatedly on the first and last days of treatment. After the first oral intake of Ro, sitting diastolic BP dropped significantly from 30 min to 24 h post-dose when compared to placebo (-10.2 +/- 1.2 mm Hg v - 0.4 +/- 2.0 mm Hg at peak and -6.9 +/- 1.8 mm Hg v 1.7 +/- 0.9 mm Hg at trough; P < .01 respectively). The trough effects of Ro and placebo after the 7th and 8th doses were -5.1 +/- 1.6 mm Hg v -0.2 +/- 1.0 mm Hg; P < .05 and -5.4 +/- 1.3 mm Hg v 2.3 +/- 1.2 mm Hg; P < .01, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

CA-125, placental alkaline phosphatase and tissue polypeptide antigen as preoperative serum markers in ovarian carcinoma

Blood samples were drawn before laparotomy in 42 cases of benign, 17 cases of borderline, and 53 cases of malignant epithelial ovarian neoplasms. The concentrations of CA-125, tissue polypeptide antigen, and placental alkaline phosphatase (PLAP) were determined. No significant difference was found between the levels of CA-125 and TPA. No significant correlation was seen between tumour type and these two markers; however, both were significantly correlated to tumour malignancy and clinical stage, and CA-125 was also correlated to tumour grade. No correlation was found between PLAP and the other markers or any of the above-mentioned parameters. If at least one of two or three markers was requested to be positive, a moderate increase in the 'detection rate' of malignant tumours was found. However, the rate of positive benign samples increased to as much as 41%. Requesting at least two markers out of two or three to be positive certainly reduced the number of 'false-positive' benign tumours, but the sensitivity for malignant tumours was reduced concomitantly to levels where marker determinations would be of little use. The study demonstrated a possible, but limited role for preoperative determinations of the markers. A combination of two or three markers was not superior to single markers. The results indicate that neither of these markers will be of significant value in a screening context.

[Maternal serum AFP determination in the 2d trimester: a suitable screening method for detection of fetuses with Down's syndrome in young females?]

The frequency distributions of maternal serum alpha-fetoprotein levels in pregnancies with fetal Down syndrome (n = 84) and in unaffected pregnancies (n = 9982) were fitted to extreme value distributions. The risk of an individual woman having a pregnancy associated with Down's syndrome was estimated depending on age and serum AFP level (MOM). A risk of Down's syndrome greater than 1:384 corresponding to the risk of a greater than or equal to 35-year-old woman was chosen to the lowest risk indicating referral for amniocentesis. The retrospective analysis of our data showed an age depending sensitivity of the maternal serum AFP screening. Only five of twenty-one cases in younger women (less than 35-year-old) but all of the thirteen cases in older women (38-40 years old) could have been detected based on low AFP levels. By calculating the sensitivity of the AFP Screening it seems to be impossible to reduce clearly the risk of Down's syndrome in young women.

Human placental lactogenic hormone as a parameter for placental function in renal transplanted women

In 13 pregnant women with renal transplants the serum concentration of placental hormones were determined in order to show their ability to predict fetal problems especially placental insufficiency. It is shown that the hPL values were increased because of reduced elimination of hPL, presumably in the renal tubuli. In this study the weight of only one newborn was over the 50th percentile in spite of the fact that all but one had hPL values over the 50th percentile and in even 8 pregnancies the values were over the 95th percentile. In most of the growth-retarded fetus's the ratio between hPL and the weight of the newborns was more complex. It is concluded that in renal transplanted pregnant women, hPL as a parameter for the placental function must be used with reservation and is not able to predict placental insufficiency.