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  • Springer  (291)
  • Nature Publishing Group  (16)
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  • 1
    ISSN: 1573-515X
    Keywords: estuaries ; mercury ; methylmercury ; sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract An overview of a comprehensive study of the behavior and fate of mercury in the estuarine Patuxent River is presented. Total Hg (HgT) and methylmercury (MeHg) exhibited weakly non-conservative behavior in the estuary. Total Hg concentrations ranged from 6 ng L-1 in the upper reaches of the sub-urbanized tidal freshwater river to 〈0.5 ng L-1 in the mesohaline lower estuary. Filterable (0.2 µm) HgT ranged from 0.2 to 1.5 ng L-1. On average, MeHg accounted for 〈5% of unfiltered HgT and 〈2% of filterable HgT. Dissolved gaseous section Hg (DGHg) concentrations were highest (up to 150 pg L-1) in the summer in the mesohaline, but were not well correlated with primary production or chlorophyll a, demonstrating the complex nature of Hg0 formation and cycling in an estuarine environment. Organic matter content appeared to control the HgT content of sediments, while MeHg in sediments was positively correlated with HgT and organic matter, and negatively correlated with sulfide. MeHg in sediments was low (0.1 to 0.5% of HgT). Preliminary findings suggest that net MeHg production within sediments exceeds net accumulation. Although HgT in pore waters increased with increasing sulfide, bulk MeHg concentrations decreased. The concentration of MeHg in sediments was not related to the concentration of HgT in pore waters. These observations support the hypothesis that sulfide affects the speciation and therefore bioavailability of dissolved and/or solid-phase Hg for methylation. Comparison with other ecosystems, and the negative correlation between pore water sulfide and sediment MeHg, suggest that sulfide limits production and accumulation of MeHg in this system.
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  • 2
    ISSN: 1432-1041
    Keywords: tramadol ; intoxication ; cerebral depression ; blood-brain barrier ; cerebrospinal fluid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Accidental intoxication with tramadol of a 6-month old infant was followed by severe cerebral depression. Studies on serum, cerebrospinal fluid, and urine drug levels indicated complete penetration of the blood-cerebrospinal fluid barrier by tramadol.
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  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung In einer quantitativen Studie an 152 männlichen und weiblichen Ratten wurden frühere qualitative Befunde über die Wirkung der Exstirpation endokriner Drüsen auf die alkalische und saure Nierenphosphatase überprüft. Die neuen Resultate stellen sich im einzelnen wie folgt dar: Alkalische Phosphatase. 1. Die Kastration männlicher Tiere bleibt ohne nennenswerten Effekt auf die Enzymaktivität. Bei weiblichen Tieren ist im Gegensatz dazu eine starke Abnahme nach Kastration zu beobachten, die in der Rinde 10 bzw. 25%, im Außenstreifen 44 bzw. 59% beträgt, je nachdem man vom Niveau der Diöstrusoder Östruswerte ausgeht. 2. Nach Adrenalektomie normaler Tiere ist die Enzymaktivität unverändert oder bis um 20% erhöht. Bei adrenalektomierten Kastraten findet sich eine jahreszeitliche Schwankung der Aktivität mit einem Maximum (Rinde 16,0, Außenstreifen 12,0 MKH) im Februar und einem Minimum (Rinde 10,6, Außenstreifen 8,4 MKH) im September. 3. Die Hypophysektomie führt bei Männchen zu einer Verminderung der Enzymaktivität in der Rinde um 20% und im Außenstreifen um mehr als 40%. Saure Phosphatase. Verglichen mit der alkalischen Phosphatase ist die Aktivität der sauren Phosphatase unter den untersuchten Umständen relativ konstant. Mit einer Ausnahme (Rindenregion nach Hypophysektomie) wird eine Abnahme der Enzymaktivität nie beobachtet. Dagegen kommt es in einigen Fällen zu einer Zunahme der Rindenaktivität, am ausgeprägtesten bei der Kastration von Weibchen. Wir sehen in diesen Fällen die Aktivitätszunahme im Zusammenhang mit Umbauvorgängen der Zellen.
    Notes: Summary Earlier histochemical results concerning the effect of the exstirpation of endocrine glands on the alkaline and acid phosphatase of the rat kidney were revised by a quantitative study of 152 female and male rats. The results are as follows: Alkaline phosphatase. 1. No considerable change of enzyme activity was found in male rats after castration. In females, however, castration induced a considerable decrease of 10 and 25% respectively in the cortex and 44 and 59% respectively in the outer stripe of the medulla; these values are on the level obtained during dioestrous and oestrous respectively (control animals). 2. Adrenalectomy either does not change the activity at all or raises it by about 20%. In adrenalectomized and castrated rats an annual fluctuation of the activity is demonstrable with a maximum in February (cortex: 16.0; outer stripe of the medulla: 12.0 MKH) and a minimum in September (cortex: 10.6; outer stripe of the medulla: 8.4 MKH). 3. In male rats hypophysectomy induces a decrease in the activity (cortex: 20%; outer stripe of the medulla: more than 40%). Acid phosphatase. The activity of acid phosphatase appears to be relatively constant. Only in one case there is a decrease in the activity (cortex of hypophysectomized rats). On the other hand there are some cases with an increase in the activity, especially in castrated female rats, which seem to be correlated to structural alterations in the cells.
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  • 4
    ISSN: 1432-1238
    Keywords: Local cerebral blood flow ; Autoradiography ; Hemorrhagic hypovolemia ; Hemorrhagic shock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective Of the animal models of human hemorrhagic shock, the volume-controlled hemorrhage model appears to come closer to the clinical situation than the commonly used pressure-controlled model, since the volumecontrolled model allows regulatory adjustment of blood pressure. The effects of volume-controlled hemorrhage on local cerebral blood flow (LCBF) of conscious animasl are not known. The present study investigates specific reaction patterns of LCBF in comparison to mean cerebral blood flow (CBF) during graded volume-controlled hemorrhagic shock in conscious rats. Methods Conscious, spontaneously breathing, and minimally restrained rats were subjected to different degrees of volume-controlled hemorrhage (taking either 25, 30, 35, or 40 ml arterial blood/kg body weight (b.w.). Thirty minutes after the completion of blood taking, LCBF was determined during hemorrhagic hypovolemia using the autoradiographic iodo (14C) antipyrine method. A group of untreated rats (no hemorrhage) served as controls. LCBF was determined in 34 defined brain structures and mean CBF was calculated. Results During less severe hemorrhage (25 and 30 ml/kg b.w.) mean CBF was significantly higher than in the control group (+19% and +25%). During severe hemorrhage (35 and 40 ml/kg b.w.) mean CBF remained unchanged compared to the control values, although significant increases in LCBF could be detected in many of the brain structures analyzed (maximum +44%). The mean coefficient of variation of CBF was increased, indicating a larger heterogeneity of LCBF values at shed blood volumes of 35 and 40 ml/kg b.w. Conclusions A comprehensive and novel description of the local distribution of CBF during graded volume-controlled hemorrhage in conscious rats shows unexpected increases in LCBF and mean CBF. This “hypovolemic cerebral hyperemia” might be caused by endogenous hemodilution, thus maintaining the blood supply to the brain during hypovolemic shock.
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  • 5
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The availability of ATR devices equipped with a diamond internal reflection element makes it possible to obtain IR absorption spectra of organic substances deposited on inorganic substrates, for example, metals, glass or quartz. The quantitative comparison of these spectra performing mass calibration by Langmuir-Blodgett (LB) layers are reported. The measurements were made in the common configuration with the specimen placed between the internal reflection element and the non-transparent support and in a second configuration with a thin transparent substrate (silicon) placed between the specimen and the internal reflection element. The band areas of the CH2 bands near 2900 cm–1 measured for the two ATR configurations were compared with those obtained from transmission measurements. The results can be partially interpreted by the equation for the effective thickness of thin layers on internal reflection elements. The relative absorbances of several bands of the TSE spectra obtained under different measuring conditions were also investigated.
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  • 6
    ISSN: 1432-1076
    Keywords: Caudal dysplasia ; Femoral hypoplasia ; Unusual facies syndrome ; Maternal diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The Caudal Dysplasia syndrome and the Femoral Hypoplasia-Unusual Facies syndrome have been reported to be more frequent among infants of diabetic mothers. We report a newborn girl who presented with features compatible with both syndromes. The possibility that both conditions represent different manifestations of the same disorder is discussed.
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  • 7
    ISSN: 1432-1076
    Keywords: Rotavirus ; Bradycardia ; Apnoea ; Neonate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rotavirus (RV), a common cause of infectious enteritis in young children including neonates, has not been associated with central nervous symptoms in standard textbooks. However, involvement of the CNS has been reported recently in case reports and small series. From 786 neonatal admissions in 1991 we retrospectively analysed the records of 215 inpatient neonates (68 preterm and 147 term infants) who developed diarrhoea during their stay on the neonatal ward and in whom stools were investigated for RV antigen by ELISA. All 215 neonates were continuously monitored for bradycardia-apnoea-episodes (BAE) at least 2 days before and during the entire diarrhoeal period. In neonates with RV antigen in stools (n=114) we found a higher incidence of BAE compared to neonates with RV negative stools (33% vs 8%,P〈0.001 for bradycardia; 7% vs 0%,P〈0.05 for apnoea). Furthermore, bradycardia episodes of RV positive neonates were more often followed by cyanosis (11 vs 0%,P〈0.05) and intervention was more often necessary (31 vs 14%,P〈0.05) than in the RV negative neonates.
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  • 8
    ISSN: 1432-1106
    Keywords: Key words GABAA-receptor α1-subunit ; Parvalbumin ; Striatum ; Pallidum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The ventral striatum is more closely related to limbic brain regions than the dorsal striatum in spite of the remarkable similarities in the structural organization between these two brain regions. The present study is focused on the comparison of ventral striatopallidal territories and the dorsal striatopallidal system regarding the GABAA-receptor α1-subunit and parvalbumin immunoreactivity, as these markers showed specific distribution patterns and coexpression sites in the more intensely studied dorsal regions. Our investigations revealed that: (1) Parvalbumin single-labeled cells and a moderate number of neurons single-labeled with the GABAA-receptor α1-subunit exist not only in the dorsal but also in the ventral striatum, including the striatal cell bridges. In addition, morphologically similar neurons positive for the α1-subunit were also found in the corpus callosum and anterior commissure. (2) A small number of double-labeled neurons was seen not only in dorsal but also in ventral striatal regions. Such cells were mainly located near the border with the globus pallidus and ventral pallidum. They are likely to represent a further type of striatal neuron. (3) The vast majority of neurons in the entopeduncular nucleus, the homologue of the primate internal globus pallidus segment, coexpressed α1-subunit and parvalbumin immunoreactivity, as reported previously for the other pallidal compartments. (4) The islands of Calleja adjoining the ventral pallidal extensions in the olfactory tubercle exhibited a strong α1-subunit immunoreactivity in the neuropil as well as somata single- or double-labeled for both markers. Our findings indicate that the dorsal and ventral striatopallidal compartments are similarly organized in general with respect to the occurrence and distribution of single- and double-labeled parvalbumin-immunoreactive and GABAA-receptor α1-subunit-immunoreactive neurons.
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  • 9
    ISSN: 1432-1238
    Keywords: Key words Local cerebral blood flow ; Autoradiography ; Hemorrhagic hypovolemia ; Hemorrhagic shock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: Of the animal models of human hemorrhagic shock, the volume-controlled hemorrhage model appears to come closer to the clinical situation than the commonly used pressure-controlled model, since the volume-controlled model allows regulatory adjustment of blood pressure. The effects of volume-controlled hemorrhage on local cerebral blood flow (LCBF) of conscious animals are not known. The present study investigates specific reaction patterns of LCBF in comparison to mean cerebral blood flow (CBF) during graded volume-controlled hemorrhagic shock in conscious rats. Methods: Conscious, spontaneously breathing, and minimally restrained rats were subjected to different degrees of volume-controlled hemorrhage (taking either 25, 30, 35, or 40 ml arterial blood/kg body weight (b.w.). Thirty minutes after the completion of blood taking, LCBF was determined during hemorrhagic hypovolemia using the autoradiographic iodo (14C) antipyrine method. A group of untreated rats (no hemorrhage) served as controls. LCBF was determined in 34 defined brain structures and mean CBF was calculated. Results: During less severe hemorrhage (25 and 30 ml/kg b.w.) mean CBF was significantly higher than in the control group (+19% and +25%). During severe hemorrhage (35 and 40 ml/kg b.w.) mean CBF remained unchanged compared to the control values, although significant increases in LCBF could be detected in many of the brain structures analyzed (maximum +44%). The mean coefficient of variation of CBF was increased, indicating a larger heterogeneity of LCBF values at shed blood volumes of 35 and 40 ml/kg b.w. Conclusions: A comprehensive and novel description of the local distribution of CBF during graded volume-controlled hemorrhage in conscious rats shows unexpected increases in LCBF and mean CBF. This ”hypovolemic cerebral hyperemia“ might be caused by endogenous hemodilution, thus maintaining the blood supply to the brain during hypovolemic shock.
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  • 10
    ISSN: 1432-1076
    Keywords: Key words Purine nucleoside phosphorylase dieficiency  ;   Immunodeficiency  ;  Varicella  ;  non Hodgkin lymphoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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