In-depth limitation of the Lamma 500 for the in situ localization of organic compounds in biological embedded tissue samples

The objective of this study was exploration of the potential, offered by the laser microprobe mass spectrometer (LAMMA), for the in situ localization of organic targets in embedded tissues by means of structurally relevant ions. A series of model systems was designed to evaluate stepwise the analytical problems involved. A preliminary screening pointed to the position of the target in comparison to the actual sample surface as a determining parameter. Refined simulations were carried out with sandwich samples, consisting of an epon carrier (thickness 1 micron), coated with microcrystalline targets and covered with a layer between 5 and 50 nm of different materials (epon, carbon, formvar). In addition to the stimulated conversion of molecular into fragment ions, the presence of a barrier leads to a drastic loss of sensitivity (20-50 x) and unacceptable degradation of the mass spectrometric quality (resolution, calibration).

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.

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.

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%.

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++.

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.

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.

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.

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].

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.

The regional registry of gastro-intestinal cancer North Baden (2.2 million inhabitants)

The advantages of a population-based registry are discussed. It is shown that a registry for gastro-intestinal cancer in a district with expert medical care based upon histo-pathological diagnosis, has the principal advantage that it limits the sites of material collection to a few effective contributors, thus providing highly accurate data. The disadvantage of collecting data by two separate steps should be tolerated. The geographic situation and the organization of the regional registry for gastro-intestinal cancer in North Baden are described and the incidences for these cancers for the years 1971-1975 are given for the population of 2.2 million.

[The patho-anatomical Regional Cancer Registry of North Baden]

Since the middle of 1976, after approximately one year of preparation, the regional cancer registry of gastrointestinal tumors in the district of North Baden has been fully in operation. Meanwhile approximately 15,000 cases of cancer have been registered retrospective including 1971. Reasons for the maximum size of a population-based registry and the method of efficiently procuring the necessary data are shown.

Spontaneous glomerular basement membrane changes in the golden Syrian hamster (Mesocricetus auratus): a light and electron microscope study

Changes in apparently healthy hamsters, consistent with proteinuria, are reported, but no IgG deposits or amyloid in the glomeruli were detected. Further investigation is required into the significance and the aetiology of these, as yet, obscure alterations.

Anti-A agglutinin from Helix pomatia as a marker for L cells

By means of fluorescein-labeled anti-AHP agglutinin isolated from the albumen gland of the snail Helix pomatia L. L cells were detected in air dried and fixed monolayer preparations, smear preparations or cryostat sections of tumours induced in two different host systems. The tumours consisting of L cells could be clearly distinguished from the surrounding normal host tissues, and also single tumour cells lying separtely in the host tissued were identified in the same unequivocal manner. The cells were marked by characteristic granular fluorescence caused by specific agglutinin binding within the cell membrane. With these results the previously expressed thesis that anti-AHP agglutinin might be used as a marker for L cells is confirmed for L cells grown in suitable host systems, too.

Cytochemical evidence for aerobic pathways in Mycobacterium lepraemurium

Three enzymes of aerobic pathways (cytochrome c oxidase, peroxidase and catalase) and one key enzyme of the tricarboxylic acid cycle (succinate dehydrogenase) were investigated for their ultrastructural localization in M. lepraemurium in infected mouse liver and in cultures of M. fortuitum as a control. All four enzymes were localized in M. fortuitum. To M. lepraemurium only cytochrome c oxidase and peroxidatic activity were detected. The localization of the latter enzyme activity was different compared with M. fortuitum. Succinate dehydrogenase was not detected in M. lepraemurium but rather surprisingly was found in the membrane of the phagosomes containing the bacteria. It is concluded that M. lepraemurium can function aerobically and has either a glyoxalate pathway or is an obligate autotroph.