Modulation of the intestinal microflora by the non-absorbable antibiotic vancomycin leads to a reduction of the tumor load in liver and spleen in a leukemic rat model.

Based on previous studies where it was shown that non-absorbable antibiotics can influence the normal hematopoiesis via changes in factors related to the intestinal microflora, the influence of vancomycin on the progression of acute myeloid leukemia was investigated in the BNML rat model. Oral vancomycin, which selectively reduces Gram-positive bacteria in the gut, leads to diminution of the leukemic load in liver and spleen by 30-60%. This 'antileukemic effect' is not dependent on Gram-negative bacteria as source for endotoxin. The presumed mechanism is a decrease of the leukemic growth fraction caused by alterations in the absorption of substances from intestinal Gram-positive bacteria.

Changes of buoyant density during the S-phase of the cell cycle. Direct evidence demonstrated in acute myeloid leukemia by flowcytometry.

Studies with synchronized or exponentially growing bacteria and mammalian cell lines are not able to demonstrate small changes in buoyant density during the cell cycle. Flowcytometric analysis of density separated acute myeloid leukemia cells, a system not dependent on time-related variables, shows that the cellular buoyant density increases slightly with up to 0.008 g/ml during the S-phase, at least in cryo-preserved cells used in this study. This contrasts with the generally accepted belief that S-phase cells have a lower or constant buoyant density. A practical implication is that separation of cell (sub)populations based on differences in buoyant density could be flawed to the extent that these populations contain S-phase cells.

Neutrophil granulation stained with May Grunwald Giemsa or pure Azure B-eosin Y quantified by image analysis.

Neutrophil granulation was quantified after staining with May Grunwald Giemsa or with the pure dyes Azure B and eosin Y. Spinner slides of the buffy coat of 3 normal subjects and 14 persons with different grades of toxic granulation were studied. Morphometric parameters were measured using an image analysis computer (Texture Analysis System, Leitz Wetzlar, FRG). The parameters for granulation varied over a wider range in Azure B (AzB) than in May Grunwald Giemsa (MGG) stained granulocytes. This is in accordance with the visual microscopy observation, that granulation is more pronounced after staining with AzB than MGG. The predominant shade of the nucleus was similar in both stains, whereas considerable and variable differences in the shade of the cytoplasm were found.

Stability of azure B-eosin Y staining solutions.

The stability of azure B-eosin Y staining solutions of varying composition and of a routine May Grunwald Giemsa (MGG) stain were studied by analysis of the density histogram of white blood cells obtained by an image analysis computer. The stability appeared to be variable and depended on the concentration of the dyes, the molarity of the buffer solutions and the presence of dimethylsulfoxide (DMSO) as a stabilizer. Although most staining solutions including the routine MGG stain showed marked loss of staining capacity soon after preparation, it was possible to obtain an azure B-eosin Y mixture with very satisfactory staining properties which did not decrease during 8 h after its preparation.

Pseudothrombocytopenia due to agglutinins.

Pseudothrombocytopenia may have any of a number of causes, one of which is agglutination in vitro. This phenomenon was found in samples of blood from six patients. A serum factor responsible for the agglutination was demonstrated. The factor was dependent upon the presence of EDTA and was more active at room temperature than at 37 C. It could be identified as an IgM immunoglobulin in four cases. In the other two cases definite characterization was not possible, but there was some evidence in favor of an IgM factor. All six patients had elevated serum IgM levels, but they had different and unrelated clinical disorders.

A commercially available interactive pattern recognition system for the characterization of blood cells: description of the system, extraction and evaluation of simple geometrical parameters of normal white cells.

A programmable system, the Textur Analyse System (T.A.S.) of E. Leitz, is described for use in interactive work on pattern recognition of white blood cells. The system appears well suited for the task of finding new parameters for the characterization of normal and abnormal blood cells. Hardware advantages such as speed of operation are coupled with software flexibility. The first application of the machine has been the extraction of some of the ordinary parameters for characterization of leucocytes. The value of each parameter has been analysed with the interactive statistical pattern analysis program (ISPAHAN). A separation in the five normal classes of peripheral white blood cells can be achieved, in which the nuclear/cell area ratio and nuclear area together with the density histograms proved to be the most important parameters. The interesting feature of the system is, however, the possibility of finding new data for the recognition of normal and abnormal blood cells.