Seasat mission overview.

During some 3 months of orbital operations, Seasat collected a unique set of global synoptic data on ocean winds, waves, temperature, and topography. All indications from a preliminary analysis of these data are that most of the mission's proof-of-concept objective-the demonstration of nearly all-weather microwave surveillance of the world's oceans-will be met.

Mariner 9 celestial mechanics experiment: gravity field and pole direction of Mars.

Analysis of the Mariner 9 radio-tracking data shows that the Martian gravity field is rougher than that of Earth or the moon, and that the accepted direction of Mars's rotation axis is in error by about 0.5 degrees . The new value for the pole direction for the epoch 1971.9, referred to the mean equatorial system of 1950.0, is right ascension alpha= 317.3 degrees +/- 0.3 degrees , declination delta = 52.6 degrees +/- 0.2 degrees . The values found for the coefficients of the low-order harmonics of Mars's gravity field are as follows: J(2)=(1.96+/-0.01)x10(-3), referred to an equatorial radius of 3394 kilometers; C(22) = -(5 +/- 1) x 10(-5); and S(22) = (3 +/- 1) x 10(-5). The value for J(2) is in excellent agreement with the result from, Wilkins' analysis of the observations of Phobos. The other two coefficients imply a value of (2.5 +/- 0.5) x 10(-4) for the fractional difference in the principal equatorial moments of inertia; the axis of the minimum moment passes near 105 degrees W.

Viking first encounter of phobos: preliminary results.

During the last 2 weeks of February 1977, an intensive scientific investigation of the martian satellite Phobos was conducted by the Viking Orbiter-1 (VO-1) spacecraft. More than 125 television pictures were obtained during this period and infrared observations were made. About 80 percent of the illuminated hemisphere was imaged at a resolution of about 30 meters. Higher resolution images of limited areas were also obtained. Flyby distances within 80 kilometers of the surface were achieved. An estimate of the mass of Phobos (GM) was obtained by observing the effect of Phobos's gravity on the orbit of VO-1 as sensed by Earth-based radiometric tracking. Preliminary results indicate a value of GM of 0.00066 +/- 0.00012 cubic kilometer per second squared (standard deviation of 3) and a mean density of about 1.9 +/- 0.6 gram per cubic centimeter (standard deviation of 3). This low density, together with the low albedo and the recently determined spectral reflectance, suggest that Phobos is compositionally similar to type I carbonaceous chondrites. Thus, either this object formed in the outer part of the asteroid belt or Lewis's theory that such material cannot condense at 1.5 astronomical units is incorrect. The data on Phobos obtained during this first encounter period are comparable in quantity to all of the data on Mars returned by Mariner flights 4, 6, and 7.

Seasat altimeter calibration: initial results.

Preliminary analysis of radar altimeter data indicates that the instrument has met its specifications for measuring spacecraft height above the ocean surface (+/- 10 centimeters) and significant wave height (+/- 0.5 meter). There is ample evidence that the radar altimeter, having undergone development through three earth orbit missions [Skylab, Geodynamics Experimental Ocean Satellite 3 (GEOS-3), and Seasat], has reached a level of precision that now makes possible its use for important quantitative oceanographic investigations and practical applications.

Determination of thymosin beta4 and protein in human wound fluid after abdominal surgery.

Wound fluids were collected up to 60 h after abdominal surgery. Immediately after obtaining the wound fluid by Robinson drainage, wound fluid was centrifuged to remove blood cells and inflammatory cells. The concentration of total protein as well as of thymosin beta(4) was determined in the cell-free supernatant solution. Total protein concentration decreased from about 50 g/L to 30 g/L within 60 h after surgery. After surgery we observed a concentration of up to 20 mg thymosin beta(4) per liter decreasing to about 1 mg/L with time. Neither thymosin beta(10) nor oxidized thymosin beta(4) was detected in human wound fluid.

[Characteristics of risk groups with an insufficient demand for dental services - results of the study of health in Pomerania (SHIP)]. / Merkmale von Risikogruppen einer unzureichenden Inanspruchnahme zahnmedizinischer Leistungen - Ergebnisse der Study of Health in Pomerania (SHIP).

AIM: The purpose of this study was to identify risk groups for low dental care utilisation and to highlight adequate determinants for necessary action. METHODS: The database was the "Study of Health in Pomerania" (SHIP), a cross-sectional sample drawn from the adult population (20 - 79 years) in a northeast region of Germany. 4310 of 7008 randomly selected inhabitants participated in the examinations (response rate 68.8 %). The use of dental care in the last year was analysed using logistic regression according to the conceptual model by Andersen and Newman. RESULTS: Multivariate analysis revealed that participation in the bonus scheme system of the statutory sickness funds (OR = 8.2) and participation in the bonus system of the private health insurance companies (OR = 2.6) as "enabling resources" predicted dental care use in the last year. "Objektive need" (OR = 1.02) is weaker associated with dental care utilisation than "subjective need", for instance the attitude towards need of regular dental checkups. Presence of own teeth is a significant predictor for dental care utilization (OR = 3.3), whereas edentulous persons, those with complete denture prosthesis, don't think about possible oral problems and don't visit the dentist at least once a year. Among "predisposing factors" only gender and education were significant determinats for dental care utilization. CONCLUSIONS: The conclusions concerning the significant influence of subjective need and promotional impact of the bonus scheme are important for health care. Financial incentives and motivation for regular prevention should be continued and upgraded. Measures to improve preventive dental care utilization should focus on persons with low educational levels and on men with inadequate dental care utilisation. The mental anchorage of the term "oral health" rather than the conventional term "dental health" is important, so that edentulous persons become conscious of regular prevention pointers to maintain a high quality of life.

A new sympatric region for distinct karyotypic forms of Hoplias malabaricus (Pisces, Erythrinidae).

Specimens of Hoplias malabaricus from Lagoa Carioca, an isolated lake of the Rio Doce State Park (state of Minas Gerais, Brazil), were cytogenetically studied. The diploid number was found to be constant, i.e., 2n = 42 chromosomes, although two karyotypic forms were found: karyotype A, characterized by 22M + 20SM chromosomes, observed only in a male specimen, and karyotype B, characterized by 24M + 16SM + 2ST and 24M + 17SM + 1ST chromosomes in female and male specimens, respectively. This sex difference found in karyotype B is related to an XX/XY sex chromosome system. Another female specimen of H. malabaricus, also carrying karyotype A, had previously been found in the same lake. The available data indicate that two sympatric cytotypes of H. malabaricus exist in the Lagoa Carioca, with cytotype A occurring at a lower frequency and differing from cytotype B by undifferentiated sex chromosomes.

Movement of sodium into human platelets induced by ADP.

1. In normal human platelets the concentrations of Na+ and K+ were 42.1 +/- 4.3 and 98.8 +/- 3.7 mequiv/l of platelet water respectively (mean +/- S.E. of 22 samples). 2. When platelet-rich plasma was incubated with 22Na+ at 37 degrees C for 2-3 h an increase in platelet Na+ concentration was found which was significant after 210 min. Platelet K+ concentration did not change significantly. The platelet 22Na+ radioactivity increased faster than did the total Na+ suggesting a Na+o-Na+ exchange process in unactivated platelets. 3. Addition of ADP to platelet-rich plasma resulted in platelet aggregation and a rapid rise (within seconds) in 22Na+-radioactivity within the platelets and after 300 s this increase diminished toward control levels. 4. Under the same experimental conditions, ADP did not bring about an increase of 36Cl- in the platelets. 5. Ouabain (10-(6) M) added to platelet-rich plasma induced an increase in Na+ concentration and 22Na+ radioactivity in the platelets, as well as a decrease in K+ concentration. ADP produced a further increase in 22Na+, which did not return toward control values, in the presence of ouabain. 6. The association of an increase in 22Na+ but not of 36Cl- accompanying aggregation by ADP suggests a selective mechanism for the movement of Na+ into platelets rather than a movement of NaCl together with water under an osmotic gradient.

Event-related potential correlates of impaired selective attention in children at high risk for schizophrenia.

Auditory event-related potentials (ERPs) associated with selective attention were recorded in 21 children at high-risk for schizophrenia and in 21 matched controls. The subjects performed a selective listening task. For behavioral evaluation, target counts on the selective listening task and on cognitive performance were assessed. Group-specific differences of ERP components could be demonstrated, as reflected by significant amplitude reductions of the frontally located negative difference wave (Nd) and of the P3 component, following selectively attended stimuli, in the high-risk children. P3 latencies tended to be prolonged in the high-risk group. Reduced Nd was found in 14 and reduced P3 in 16 high-risk children among the 21 matched pairs. Significant correlations between the ERP reductions and psychometric deficit (counting accuracy) were observed. Mismatch negativity (MMN), an ERP component associated with automatic processing of physically deviant stimuli, did not differentiate significantly between groups, but was distinctly reduced in the high-risk group. The Nd and P3 reductions suggest deficits of selective attention in a considerable number of the subjects genetically at risk for schizophrenia. The present findings are discussed with respect to their relevance as indicators of a predisposition to schizophrenia.

Improved event-related potential signs of selective attention after the administration of the cholecystokinin analog ceruletide in healthy persons.

Cholecystokinin (CCK) is co-localized with dopamine (DA) in neurons of the mesolimbic-frontocortical dopamine (DA) system, considered essential for the pathology of psychotic behavior and associated attention deficits. The present experiments in 13 healthy men aimed at examining the effects of the CCK analog ceruletide on attention as reflected by event-related brain potentials (ERPs). Subjects were tested according to a double-blind cross-over design on three occasions, following intravenous infusion of placebo, 0.5 microgram ceruletide, and 2.5 micrograms ceruletide. ERPs were recorded during the subject's performance on an auditory selective attention task including the concurrent presentation of frequent standard tones and infrequent deviant tones which the subject had to listen to, or to ignore. The processing negativity (PN) over frontocentral cortical areas, reflecting selective attention, was higher after ceruletide than placebo, this increase being most pronounced after the 2.5 micrograms dose (placebo -1.29 +/- 0.38 microV versus ceruletide -3.02 +/- 0.65 microV, p < .05). ERP signs of a general increase in cortical arousal after ceruletide did not reach significance. Likewise, mismatch negativity, an indicator of preattentive processing of stimulus deviance, was not significantly affected by the peptide. The results indicate that ceruletide affects human brain function primarily by improving selective attention.

Endogenous event-related brain potentials and psychometric performance in children at risk for schizophrenia.

Two independent groups of high-risk children for schizophrenia and their matched control children were submitted to the following experiments: an auditory oddball paradigm registrating late event-related potentials (ERPs) and a psychometric test battery including the assessment of Wechsler Intelligence Scales, reaction times (after regular and irregular preparatory intervals), and the d2-attention test. The study was intended to clarify whether long-latency ERPs and the selected psychometric tests would contribute to reliably differentiating between these groups. The results showed significantly prolonged latencies of the P3 component of the ERPs to rare, task-relevant target stimuli in both high-risk groups compared with the controls. Similarly, the N2 latencies were delayed in both groups. By contrast, ERP patterns to frequent, nontask-relevant stimuli were very similar, with no significant differences between high-risks and normals; nor did any ERP amplitudes show significant differences. The data are interpreted as a reflection of a subtle deficit in maintaining attention and a subsequent impairment of stimulus discrimination in high-risk children. This is consistent with the psychometric findings of higher error scores in target counts and d2-test, and significantly prolonged reaction times after regular preparatory intervals (PIs) in the high-risks. The findings may hint at a vulnerability for schizophrenia in high-risk children. Given the high prevalence of the attentional dysfunctions in both high-risk groups, however, it is hypothesized their presence does not necessarily imply an unequivocal manifestation of schizophrenia.

Comparison of uptake and degradation of low density lipoproteins by arteries and veins of rabbits.

The uptake and degradation of low density lipoproteins were compared in arteries and veins of rabbits in vivo. Rabbits were injected with low density lipoproteins labelled singly with 125I (125I-LDL) or doubly with 131I and with [125I]tyramine cellobiose (TC-LDL) which remains trapped intracellularly. After increasing times up to 24 h the largest vessels were perfused to remove blood, fixed in situ and excised. When the uptake of 125I-LDL by arteries and veins was compared on the basis of luminal surface area, there were no significant differences up to 3.5 h. When degradation rates of double labelled LDL were compared after 24 h on the same basis, the arteries contained significantly more TC label than the veins, but when the comparison was based on dry weights there were no significant differences. These results show that veins, like arteries, take up LDL from the circulating blood; and they suggest that the preferential accumulation of LDL in arteries susceptible to atherosclerosis may be accounted for, at least in part, by more degradation of LDL in arteries than in veins.

Adrenaline increases the uptake of low-density lipoproteins in carotid arteries of rabbits.

The uptake of low-density lipoprotein was compared in carotid arteries of anaesthetized male New Zealand rabbits after infusing alternate carotids with adrenaline, or with saline as a control. The infusions were at approximately 2% of the carotid blood flow, the adrenaline being at approximately 10 nM in the carotid blood. Human low density lipoprotein, methylated to prevent recognition by the high affinity receptor (m-LDL), was labelled with 125I and injected intravenously. Adrenaline infusions for 2 or 4 h significantly increased m-LDL radioactivity in the carotid walls. The radioactivity of reinjected red cells labelled with 51Cr was the same in the walls of both carotids. This excluded the possibility that the excess LDL radioactivity in adrenaline infused carotids was accounted for by increased amounts of blood in the arterial wall. It also made it improbable that the excess LDL resulted from decreased elimination through a vasoconstriction effect of adrenaline on the vasa vasorum, which should have decreased the amount of radioactivity due to red cells. The results, therefore, suggest that adrenaline at its pathophysiological blood concentrations accelerates the uptake of LDL by large arteries in rabbits.

Atherosclerotic plaque caps are locally weakened when macrophages density is increased.

The density of macrophages, identified by the antibody EBMII, in human aortic plaque caps was counted. A contiguous strip of cap tissue was tested mechanically. Aortic plaque caps which had undergone rupture (ulceration) at one end (n = 18) were compared with caps of intact plaques (n = 22). The caps of ruptured plaques showed a significant increase in macrophage density, an increased extensibility and decreased maximum stress (force per unit area) at fracture when compared with caps from intact plaques.

Effects of reserpine on expression of the LDL receptor in liver and on plasma and tissue lipids, low density lipoprotein and fibrinogen in rabbits in vivo.

The effects of administering reserpine (0.1 mg/kg) or 17alpha-ethinyloestradiol (2.5 mg/kg) to New Zealand White rabbits on low density lipoprotein receptors in liver, on plasma low density lipoprotein and fibrinogen and on plasma and tissue lipids were determined. Blood pressure and heart rate were also followed. The drugs were injected subcutaneously into conscious unrestrained rabbits for 5 days. On the 6th day homologous 125I-tyramine cellobiose labelled low density lipoprotein (125I-TC-LDL) was injected intravenously and 24 h later the animals were killed. Compared to controls, reserpine significantly increased LDL receptor expression in the liver by about threefold, and reduced total cholesterol in plasma, aorta and heart, without affecting plasma triglycerides. The reductions in plasma cholesterol and heart were due to decreases in both unesterified and esterified cholesterol. Similar effects were observed with oestrogen, except that there was no change in esterified cholesterol in aorta. In liver, a decrease of 24% in total cholesterol was due mainly to decreased esterified cholesterol. In adrenal glands total cholesterol increased by 25%. Reserpine significantly accelerated the plasma clearance of intravenously injected homologous 125I-TC-LDL and reduced its accumulation in aortic wall. Neither reserpine nor oestradiol affected blood pressure, haematocrit or plasma fibrinogen. The results suggest that reserpine is an affective anti-atherogenic drug capable of decreasing cholesterol in plasma, arteries and heart by increasing high affinity LDL receptors in the liver.

Collagen types I and III, collagen content, GAGs and mechanical strength of human atherosclerotic plaque caps: span-wise variations.

Measurements of total collagen, of the ratio of collagen types III/(I+III) and of sulphated glycosaminoglycans (GAGs) were compared with mechanical strength for individual ulcerated and non-ulcerated human aortic plaque caps and with intima adjacent to the plaques. The distributions of the collagen type ratio were similar for both ulcerated and non-ulcerated plaque caps but different from that of the adjacent intima. The proportions of different collagen types were not related to fracture stress and are thus unlikely to affect the potential to ulcerate. The distributions of the sulphated GAGs showed lower amounts for the plaque caps compared with the nearby intima, with the centres of ulcerated plaque caps having the lowest values. Total collagen had higher values in the peripheries of plaque caps compared with the nearby intima, but was distinctly lower in the centres of ulcerated plaque caps. Plaque caps appeared to require a higher collagen content than adjacent intima to support a given level of mechanical strength, suggesting that while collagen production had occurred in the plaque caps it was not as efficiently organized to resist fracture as a similar amount of collagen in the adjacent intima. Ulcerated plaque caps are notable for much larger transverse (centre vs. periphery) gradients of connective tissue constituents than for non-ulcerated plaque caps. The development of these transverse gradients may be a critical aspect in determining the propensity of a plaque to ulcerate.

The biologic background to some therapeutic uses of aspirin.

The therapeutic success of aspirin as an effective analgesic, antipyretic, and anti-inflammatory drug had been universally established for many decades before its mode of action was discovered in 1971. This mode of action is the prevention, or diminution, of prostaglandin biosynthesis through the inhibition of the enzyme, cyclo-oxygenase. Demonstrations of the major contributions of prostaglandins to pain, fever, and other cardinal features of inflammation provided rational explanations for the well-established therapeutic uses of aspirin. It had been shown earlier that aspirin antagonized two mediators of inflammation by an indirect process. While aspirin's mode of action was being discovered, research on platelets in hemostasis and thrombosis was also being done. It was shown that aspirin inhibited an exocytotic reaction (the release reaction) of platelets. This reaction was regarded as essential for their aggregation as thrombi in, most importantly, coronary and cerebral arteries. This observation was the starting point of an enormous effort, still going on to determine through both fundamental and clinical investigations, the therapeutic potential of aspirin as an antithrombotic drug. Costly clinical trials have provided evidence in favor of aspirin preventing thrombotic events affecting the brain; its effectiveness against coronary thrombosis is not yet definitely established. Possible explanations for this situation will be considered on the basis of rapidly advancing biologic knowledge about the mechanism of thrombosis.

Effect of deoxycorticosterone acetate on blood pressure in relation to accumulation of low-density lipoprotein and fibrinogen by aorta and other tissues of normotensive Wistar rats.

OBJECTIVE: To evaluate the effect of different 4-week doses of deoxycorticosterone acetate (DOCA), together with 0.9% sodium chloride in the drinking water (DOCA-salt) on the blood pressure and on the accumulation of low-density lipoprotein (LDL) and fibrinogen in artery walls ad other tissues in conscious, unrestrained, normotensive Wistar-Kyoto rats. METHODS: The accumulation of LDL labelled with 125I via the adduct tyramine cellobiose ([125I]-TC-LDL) and of fibrinogen similarly labelled with 131I ([131I]-TC-fibrinogen) was compared in aortic walls, heart, liver, kidney, lung. skeletal muscle, and adrenal gland tissues during the final 24 h of a 4-week administration of DOCA-salt, with vehicle-salt and saline as controls. RESULTS: In control and vehicle rats the blood pressure did not change significantly during the last 5 days of treatment. Administration of DOCA-salt produced a dose-dependent increase in blood pressure during the same period. DOCA-salt administration increased LDL accumulation in the aorta and the heart and decreased LDL accumulation in the adrenal gland compared with those in rats of the control and vehicle groups. DOCA-salt administration did not affect fibrinogen accumulation significantly. CONCLUSION: DOCA-salt treatment produces an increase in arterial blood pressure accompanied by an increase in LDL accumulation by the aortic wall and heart and a decrease in LDL accumulation by the adrenal gland. These observations raise the possibility that one mechanism by which hypertension affects atherosclerosis is through increased LDL accumulation in arterial walls.

Plasma separation and bilirubin adsorption after complicated liver transplantation: a therapeutic approach to excessive hyperbilirubinemia.

BACKGROUND: Severe hyperbilirubinemia is known to exert multiple toxic effects. Thus, a reduction in bilirubin by use of various adsorbent columns has been reported for a variety of hepatic disorders, but no experience with liver transplant patients is available as yet. METHODS: Plasma separation and bilirubin adsorption by an anion-exchange adsorbent column (BR-350) were performed in two patients with severe jaundice (total serum bilirubin > 55 mg/dl) and multiple organ failure that had developed after orthotopic liver transplantation. RESULTS: The procedure resulted in an 18% to 35% reduction in total bilirubin after each session, accompanied by a remarkable clinical improvement. Both patients finally recovered and had a favorable outcome. No complications or side effects of bilirubin adsorption were observed during any of the six sessions. CONCLUSIONS: Bilirubin adsorption is a safe and effective treatment. It should be considered as supportive therapy for excessive hyperbilirubinemia after liver transplantation. In selected cases, retransplantation may thus be avoided.

Molecular and biological characteristics of a novel HIV-2 isolate, HIV-2HOM.

In 1991 a new HIV-2 isolate (HIV-2HOM) was isolated first from a German individual most likely infected in West Africa in the beginning of the 1970s. The virus was isolated from both, the plasma and the peripheral blood lymphocytes of the patient by using OKT-3-stimulated cord blood lymphocytes. The recovered viruses could be further propagated on Jurkat cells and exhibited a broad cell tropism. Biochemical and antigenic properties of HIV-2HOM were examined by radioimmunoprecipitations. For a more detailed molecular characterization, a 1520 bp DNA fragment from the env gene and a 722 bp DNA fragment from the pol gene were amplified by polymerase chain reactions, cloned and sequenced. A comparison of both sequences to prototypic HIV-2 and SIV isolates revealed a close relationship to HIV-2ST. This strain originated from an asymptomatic Senegalese individual and is supposed to be of reduced pathogenicity. Taking into account genetic data, it may be assumed that HIV-2HOM and HIV-2ST are closely related strains with different growth characteristics and pathogenic features.