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K M Townsend

Publications and source records attributed to K M Townsend.

41 records · Page 3Linked to original sources
PubMed1980

Giant lysosomes, a cytoplasmic marker in osteoclasts of beige mice.

The beige mouse (bg/bg) is an analogue of the Chediak-Higashi syndrome (CHS) in man. The disorder is characterised by the presence of enlarged cytoplasmic granules, said to be lysosomes, in many cell types. The present report describes giant lysosomes defined as lysosomes greater than 1.0 micrometers in diameter, in osteoclasts of beige mice. The giant lysosomes contained both acid phosphatase and aryl sulphatase and were present in osteoclasts of beige mice aged from at least 4 days to 3 months. There is some evidence that the giant lysosomes form by fusion of smaller structures. Since giant lysosomes were also seen in osteoclasts from mouse strains not suffering from CHS, e.g., CBA mice, a quantitative survey was carried out. It was shown that osteoclasts from beige mice aged from 4 days to 3 months contain significantly increased numbers of giant lysosomes when compared with osteoclasts from CBA mice and CBAXbg/bg F1 hybrids. The giant lysosomes of the beige mouse osteoclast are currently being used as cytoplasmic markers in experiments on the cell of origin of the osteoclast.

Acid Phosphatase↗
PubMedDate not supplied

REP-PCR analysis of Pasteurella multocida isolates that cause haemorrhagic septicaemia.

Amplification of multiple P multocida genomic DNA fragments by outwardly-directed primers based on the repetitive extragenic palindromic (REP) consensus sequence, generated complex profiles in a PCR-based fingerprinting method known as REP-PCR. Polymorphisms within REP-PCR profiles were used to characterise 38 isolates of P multocida. The high degree of homogeneity observed among haemorrhagic septicaemia (HS) strains of serotype B and E provided evidence of a disease-associated REP profile that may serve as a novel method for the identification of HS strains regardless of serotype. REP-PCR profiles of other P multocida serotypes were highly variable, illustrating the potential of this technique for the molecular fingerprinting of fowl cholera or atrophic rhinitis isolates. A specific amplified REP fragment was isolated and used to probe membrane-bound digested P multocida genomic DNA. Hybridisation patterns not only distinguished HS-causing isolates from non-HS P multocida, but also demonstrated a degree of relatedness between HS and HS-like strains.

Animals↗
PubMedDate not supplied

Intracellular particle dissolution in macrophages isolated from the lung of the Fischer (F-344) rat.

Alveolar macrophages were removed from male F-344 rats by bronchoalveolar lavage and maintained in vitro for 14 days. Over this period the macrophages remained viable as judged by propidium iodide exclusion, lysosomal uptake of acridine orange, and phagocytosis of 1.75-microns latex beads. After 7 and 14 days of culture the cells contained lipid droplets. The macrophages were shown to ingest and dissolve monodisperse 57Co3O4 particles, which were relatively insoluble in extracellular medium. The fraction of 57Co3O4 dissolved intracellularly was determined at intervals during the culture period. The mean dissolution rate (+/- SEM) was 0.36 +/- 0.02% per day for the F-344 rat. This was lower than 1.4 +/- 0.05% per day estimated by Kreyling in macrophages from the beagle dog. The significance of this difference is discussed.

Animals↗
PubMedDate not supplied

Osteoclasts derive from hematopoietic stem cells according to marker, giant lysosomes of beige mice.

To ascertain the origin of multinucleated osteoclasts from hematopoietic stem cells, giant lysosomes peculiar to cells of beige mice (bg bg) were used as marker cells of that provenance. Radiation chimeras were established reciprocally between bg bg mice and osteopetrotic mi mi mice with defective osteoclasts. As a result, all the derivative cells of the hematopoietic stem cell would depend on the donor's cell line, whereas osteogenesis would remain the province of the host. It was affirmed in the chimeras mi mi/bg bg that the osteopetrosis was cured within six weeks. Thereafter the definitive osteoclasts of the chimeras contained giant lysosomes attributable to the beige cell line. However, the cure was well advanced before donor osteoclasts were prominent, for which several reasons are offered. In the mouse chimeras, bg bg/mi mi, there was a delay of some six weeks before osteopetrosis became evident, histologically before radiologically, at the major metaphyseal growth centers. During the period one to two months after establishment, osteoclasts appeared to be a mixture of two cell lines according to quantitative assessments for giant lysosomes. Assessments consisted of measurements of the percentage area of osteoclasts occupied by lysosomes over 1 micrometer diameter. The means were 0.018% +/- 0.008% for nonbeige stock and 2.09% +/- 0.58% for beige stock.

Animals↗