Multidimensional flow cytometric blood cell differentiation without erythrocyte lysis.

Forward light scattering, orthogonal light scattering, and the fluorescence intensities of unlysed peripheral blood cells, labeled with CD45-phycoerythrin and the nucleic acid dyes LDS-751 and thiazole orange, were measured simultaneously, utilizing a flow cytometer. Erythrocytes, reticulocytes, platelets, neutrophils, eosinophils, basophils, monocytes, lymphocytes, nucleated erythrocytes, and immature nucleated cells occupied unique positions in the five-dimensional space created by the listmode storage of the five independent parameters. A software program was developed which identified and enumerated each of these cell populations. Platelets in this study were identified by LDS-751 staining, in addition to their forward and orthogonal light-scattering characteristics. Validation of this approach was obtained by demonstrating that all CD41- or CD42-expressing platelets also stained with LDS-751. Furthermore, the staining by LDS-751 did not change following platelet activation with ADP. The quantification of erythrocytes, platelets, neutrophils, eosinophils, monocytes, and lymphocytes correlated well with data obtained with a commercial hematology whole blood analyzer (H-1). Reproducibility of the identification of these populations was shown by repeated measurement of the same sample and by staining and analysis of multiple aliquots of identical blood samples. Stability studies demonstrated that 8 hours after blood collection, the number of damaged cells increased. This could be measured by a greater thiazole orange uptake by the damaged cells. This investigation demonstrates the feasibility of multidimensional flow cytometric blood cell differentiation for an automated whole blood cell analysis without the necessity of erythrocyte lysis. The ability to simultaneously identify reticulocytes, nucleated erythrocytes, and immature nucleated cells in one measurement is unique and promises to be a powerful tool for the assessment of abnormal blood samples.     

Pulmonary dirofilariasis diagnosed by fine needle aspiration biopsy. A case report

A case of pulmonary dirofilariasis in a 62-year-old female was diagnosed by fine needle aspiration biopsy. A review of the literature revealed this to be the first reported case diagnosed by this method. The presence of bilateral lesions in this patient is an uncommon finding for this entity.     

15N-labeled Escherichia coli tRNAfMet, tRNAGlu, tRNATyr, and tRNAPhe. Double resonance and two-dimensional NMR of N1-labeled pseudouridine

The N1 imino units in Escherichia coli tRNAfMet, tRNAGlu, tRNAPhe, and tRNATyr were studied by 1H-15N NMR using three different techniques to suppress signals of protons not attached to 15N. Two of the procedures, Fourier internuclear difference spectroscopy and two-dimensional forbidden echo spectroscopy permitted 1H and 15N chemical shifts to be measured simultaneously at 1H sensitivity. The tRNAs were labeled by fermentation of the uracil auxotroph S phi 187 on a minimal medium containing [1-15N]uracil. 1H and 15N resonances were detected for all of the N1 psi imino units except psi 13 at the end of the dihydrouridine stem in tRNAGlu. Chemical shifts for imino units in the tRNAs were compared with "intrinsic" values in model systems. The comparisons show that the A X psi pairs at the base of the anticodon stem in E. coli tRNAPhe and tRNATyr have psi in an anti conformation. The N1 protons of psi in other locations, including psi 32 in the anticodon loop of tRNAPhe, form internal hydrogen bonds to bridging water molecules or 2'-hydroxyl groups in nearby ribose units. These interactions permit psi to stabilize the tertiary structure of a tRNA beyond what is provided by the U it replaces.     

Nucleotide sequence encoding the biosynthetic dehydroquinase function of the penta-functional arom locus of Aspergillus nidulans.

The nucleotide sequence of a 1.9 Kb HindIII fragment of DNA derived from the arom locus of A.nidulans and encoding the biosynthetic dehydroquinase activity has been determined. The sequences encoding the biosynthetic and catabolic dehydroquinase enzymes of A.nidulans show no detectable homology, strongly suggesting convergent evolutionary pathways. The messenger RNA specified by the arom locus was detected as a 5.3 Kb RNA species.     

Tetanus toxin as a tool for studying epilepsy

The use of tetanus toxin, injected into the hippocampus of the rat, to produce an "animal model" of chronic limbic epilepsy is described. This model has yielded information complementary to that derived from other animal models and has several important advantages: while it involves spontaneous seizures, it occurs without gross damage to the brain ; it is eventually reversible in terms of fits and the overall reappearance of the EEG. It can therefore be used to look both at the effects of ongoing epilepsy and also at the long-term changes in brain function induced by previous epilepsy. Evidence is presented that the toxin probably remains localised at the site of injection. The information which has so far been obtained with this model on the relation between epilepsy and abnormal behaviour is summarised. In particular, it appears that the epilepsy produces long-term deficits in the animals' ability to learn and remember of a sort which suggest that an enduring malfunction has been induced in the hippocampus. The significance of the findings for clinical research and for future investigation of the nature of epilepsy are described. It is emphasised that the neurotoxins may be usefully exploited not only for investigating the molecular basis of neuronal mechanisms but also for inducing long-lasting plastic changes in integrated brain function.     

A population genetic study of the Banks and Torres Islands (Vanuatu) and of the Santa Cruz Islands and polynesian outliers (Solomon Islands)

As part of a multidisciplinary survey of populations in the Banks and Torres Islands of Vanuatu and the Southern and Central Districts of the Solomon Islands, nearly 2,400 persons have been tested for ABO blood groups and a number of serum protein and red cell enzyme genetic marker systems. For the ABO system, the populations are characterized in general by high gene O and low gene B frequencies except in two of the Polynesian Outlier Islands, Rennell and Bellona, which have high frequencies of B. Among the serum proteins, several alleles have distributions indicating significant movement of people between islands. These include Albumin ^{New Guinea} and the transferrin alleles Tf, and Tf, and Tf. Similar specific alleles for red cell enzymes also show distributions reflecting interisland population movement as well as contact with persons from outside the southern Pacific region. Examples are ACP in the acid phosphatase system, PGM and PGM, PGM and PGM, PGK⁴ and also HbJ^Tongariki. The data available for 11 polymorphic systems were used to generate genetic distances. Of the four Polynesian Outlier Islands, Anuta is most remote genetically, with Rennell and Bellona also relatively isolated. The fourth Polynesian Outlier, Tikopia, occupies a position genetically close to the Melanesian populations of the Banks and Torres Islands and the southern Solomons. The history of early European contact and voyaging in the Pacific, as well as archaeological and linguistic evidence and local legends, indicate that significant movements of people occurred between islands and provided opportunities for genes to be introduced from Europeans, Africans, and Asians. The genetic marker studies give evidence for genes from all these sources, though at a low level. Despite this admixture, the Polynesian Outlier and Melanesian populations have preserved their own distinctive genetic patterns.     

Scanning electron microscope study of Candida albicans invasion of cultured human cervical epithelial cells

The invasion of monolayer cultures of epithelial cells from the human uterine cervix by clinical isolates of Candida albicans was observed. Blastospores settle on the epithelial cells and produce germ tubes within 2 h. Hyphae penetrate the epithelial cell walls and destroy the cells, weaving in and out of the cytoplasm. No phagocytosis of yeast cells by epithelial cells was seen.     

The corrected nucleotide sequence of yeast leucine transfer ribonucleic acid

The nucleotide sequence of “Renaturable” leucine transfer RNA from Baker's yeast has been re-investigated. The results showed that (i) this tRNA has a sequence of DCD at positions 19–21, (ii) it has an anticodon m⁵CAA and (iii) it has a pseudouridine at position 40.