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Biomedical subjects

W Jacob

Publications and source records attributed to W Jacob.

At least 55 records · Page 3Linked to original sources
PubMed1985

The prevention of Ca2+ overload in vascular smooth muscle by flunarizine as detected by Laser Microprobe Mass Analysis (LAMMA).

In vitro exposure of depolarized caudal artery preparations of the rat to a high calcium concentration resulted in a strong contraction of the smooth muscle cells. This muscle contraction was suppressed by flunarizine. It was shown cytochemically, using the combined oxalate-pyroantimonate method for the localization of calcium, that a considerable amount of electron-dense precipitate was seen over the depolarized muscle cells after incubation in a calcium containing medium. On the other hand this precipitate was not present on the smooth muscle cells when flunarizine was added to this incubation medium. The reaction product was only present in the extracellular space. These results were controlled by Laser Microprobe Mass Analysis. By evaporating and ionizing small parts of the smooth muscle cells (+/- 1 micron), it was confirmed that the cytochemical method indeed demonstrated calcium, with negligible interference of other cations.

Animals↗
PubMed1984

Effect of hypnorm, chloralosane and pentobarbital on the ultrastructure of the inner membrane of rat heart mitochondria.

Rat heart mitochondria were isolated from four groups of animals treated in a different way. The animals of the first group were killed after decapitation (D-group) without previous anaesthesia. The three other groups of animals were anaesthetised with different anaesthetics. The second group (N-group) was anaesthetised with nembutal (sodium pentobarbital), the third group with chloralosane (C-group) and the fourth group with hypnorm (H-group). From these three anaesthetics only nembutal is known to interact with mitochondria. After retrograde perfusion and excision of the heart, mitochondria were prepared from the ventricles by standard methods. After freeze-fracturing the mitochondrial suspension, the intramembrane particle dimension and density on both fracture faces of the inner mitochondrial membrane were measured. The intramembrane particle diameter on the P-face of the inner membrane of the N-group mitochondria was significantly different from D-, C- and H-group mitochondria. Also the density and diameter of the intramembrane particles on the mitochondrial inner membrane of D-group mitochondria compared to C- and H-group mitochondria were significantly different at the 95% level of confidence. Between C- and H-group mitochondria no differences of these parameters were observed. From these results it is clear that, depending on the pretreatment of the animals, a different substructure of the inner membrane of heart mitochondria is obtained.

Animals↗
PubMed1984

A new image analysis method for the quantification of neovascularization.

In a foregoing paper, an attempt has been described to quantify the neovascularization in the chorioallantoic membrane (CAM) by using the method of automatic image analysis. In this case 5 to 10 min were necessary to measure the neovascular response of one CAM preparation (i.e. to obtain a value for the degree of angiogenesis). The accuracy of reproducibility of the measurements was about +/- 20%. In this paper, we describe a new method which only requires about 55 seconds for the measurement of one specimen with an accuracy of about +/- 12%.

Allantois↗
PubMed1983

Influence of econazole and 5-fluorocytosine on the ultrastructure of Aspergillus fumigatus and the cytochemical localization of calcium ions as measured by laser microprobe mass analysis.

The ultrastructural changes and the localization of Ca++ ions have been investigated in Aspergillus fumigatus after exposure in vitro to econazole (50 micrograms ml-1) and to 5-fluorocytosine (100 micrograms ml-1) for 24 h. The changes obtained with econazole concerned the cell periphery, necrotization of mitochondria and hyperactivity of the central vacuole. After cytochemical Ca++ localization a marked increase in precipitate was observed on mitochondria, vacuoles and collapsed membranes, compared to the control. Laser microprobe mass analysis confirmed that the measured amount of Ca++ ions corresponded to the degree of precipitate formation in the different cellular compartments. After exposure to 5-fluorocytosine, abnormal behaviour of the nuclei and internal lipidification of the mitochondria and of the cytoplasm were seen. No discernible Ca++ activity was present on the cellular structures by cytochemical localization. Assay by laser microprobe mass analysis, however, showed a slight increase in Ca++ which points to a structural bonding of the Ca++.

Aspergillus fumigatus↗
PubMed1983

[Typology, place, time].

The conception of the kinetic typology (H. Tellenbach ) represents a substantial extension of the genetically and peristatically , that means the constitutionally referred typology. By the characteristics of the " Typos " which became traditional form the antiquity one can gain important dimensions concerning the patient's existance and way of living to the purely clinical-phenomenologic exposition of the type of disease. In this correlation Typos , Topos and Chronos prove to be categories related to each other on principle within the frame of a kinetic typology.

Depressive Disorder↗
PubMed1982

Characterisation of an unusual bacterium isolated from genital ulcers.

The preliminary characterisation of an unusual gram-negative bacillus isolated from genital ulcers in Swaziland is reported. Like Haemophilus ducreyi, it is an oxidase positive, nitrate-reductase-positive gram-negative rod that forms streptobacillary chains in some circumstances; it was therefore called the "ducreyi-like bacterium" (DLB). Distinguishing features of DLB are production of alpha-haemolysis on horse-blood agar, stimulation of growth by a microaerophilic atmosphere and by a factor produced by Staphylococcus aureus, a strongly positive porphyrin test, and a remarkable ability to undergo autolysis. DLB had a guanine + cytosine value of c. 50 mole% but it cannot be classified, even at the genus level, until more taxonomic data are obtained.

Bacteria↗
PubMed1981

Biophysical characterization of Artemia salina (L.) extracellular haemoglobins.

Sedimentation coefficients (s0 20,w) of 11.57 +/- 0.10 S and 11.52 +/- 0.09 S were assigned for Artemia salina (L.) extracellular haemoglobins II and III respectively. These values are not significantly different. The molecular weights, M0w and M0z, of the native haemoglobins as determined by the high-speed sedimentation-equilibrium method were for haemoglobin II 239 400 +/- 7200 and 240 400 +/- 2600 respectively, and for haemoglobin III 216 300 +/- 6500 and 219 300 +/- 4500 respectively. The observed increase of Mapp. with concentration suggested that association was occurring over the concentration range investigated. Exposure of haemoglobin II to either 6 M-guanidinium chloride or to low pH (pH 4) resulted in dissociation to units of approximately half the size of the native protein, with molecular weights approx. 115 000. Electron-microscopic observations indicated a molecular structure composed of two stacked lobed discs. These results strongly support the dimeric model for Artemia haemoglobins proposed by Moens & Kondo [(1978) Eur. J. Biochem. 82, 65-72].

Animals↗
PubMed1981

Some modifications of freeze-fracture replica preparation.

Freeze-fracture replicas are freed from lipid material by saponification in a hot sodium hydroxide solution and subsequently rinsed with 10% ethanol in distilled water. All manipulations are carried out with a glass bead fashioned onto a pasteur pipette. A stable, two-layered plastic support film has been developed to allow the use of grids with larger openings so that more of the specimen is observable.

Freeze Fracturing↗
PubMed1981

Renal disease in chronic experimental Trypanosoma gambiense infections.

Two recently isolated stocks of Trypanosoma brucei gambiense of human origin gave rise to a moderate to severe proliferative or membranoproliferative glomerulonephritis in 40 or 44 NMRI and C57BL/6J mice infected for 7-22 weeks. Extensive granular deposits of C3, IgG1 and IgG3 were found in the mesangium, together with smaller quantities of IgG2a, IgG2b, and IgM. No trypanosomal antigen could be detected in the deposits though specific anti-trypanosoma antibodies were found in kidney eluates. By electron microscopy, a conspicuous proliferation of mesangial and endothelial cells was observed and electron-dense deposits were seen in a mesangial and subepithelial localization. With one of these trypanosome stocks, four of seven Wistar rats infected for 9-15 weeks developed morphologically similar glomerular lesions. Four other trypanosome stocks did not evoke renal alterations in 17 other rats infected for 13-56 weeks. Experimental infection in mice or rats appears to be a suitable model for the study of renal disease in chronic African sleeping sickness.

Animals↗
PubMed1979

Regular, rodlike, macromolecular structures in Artemia salina.

Artemia salina of different origins and in different developmental stages contains regular, rodlike, macromolecular structures. The particles were visualized by electron microscopy after negative staining. They can be purified from the postmitochondrial supernatant by sucrose gradient centrifugation in the presence of EDTA. Their size distribution has been measured from electron micrographs. The particles are probably nucleoprotein complexes.

Animals↗