Osteoporosis of Lumbar Vertebrae and Calcification of Abdominal Aorta in Women Living in Durban

To try to establish whether mechanical stress and muscular activity in earlier life influence the incidence and severity of spinal osteoporosis in old age lateral x-ray films of the lumbar vertebrae were obtained from three matched groups, each of 100 women 50 to 90 years old. Group A was of rural Bantu accustomed to carrying heavy loads on their heads. Group B was of urban Bantu, mainly in domestic service. Group C was of women of European origin.Severe osteoporosis occurred in three cases from group A, two from group B, and 14 from group C. Lesser degrees of osteoporosis could not be assessed precisely enough for inclusion in these figures. Evenly biconcave vertebral bodies, strongly suggestive of osteomalacia, were seen in 10 from group A, five from group B, and one from group C. In many Bantu subjects the fifth lumbar vertebra appeared flattened though of good radiodensity and with no marked changes in the other vertebrae. Twenty-eight of these were from group A, 16 from group B, and none from group C.About a third of each group showed severe degenerative changes in the spine; another third showed milder changes. More cases of spondylolisthesis occurred in the Bantu groups than in the white group. Severe calcification in the abdominal aorta was noted in 24 women in group C. Mild signs occurred in 35 further women from group C, in six from group B, and in only one from group A.     

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New classes of Gram-positive selective antibacterials: inhibitors of MRSA and surrogates of the causative agents of anthrax and tuberculosis

An antimicrobial phenolic stilbene, (E)-3-hydroxy-5-methoxystilbene, 1 was recently isolated from the leaves of Comptonia peregrina (L.) Coulter and shown to possess inhibitory activity against several Gram-positive bacteria, including isolates of methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium bovis BCG, and avirulent Bacillusanthracis (Sterne strain), among others. These results prompted the design and synthesis of two new classes of compounds, phenoxystyrenes and phenothiostyrenes, as analogs of the natural antimicrobial stilbene. These and additional stilbenoid analogs were synthesized using new, efficient, copper-mediated coupling strategies. Minimum inhibitory concentration (MIC) antimicrobial assays were performed on all compounds prepared. These preliminary structure-activity relationship studies indicated that both new classes of synthetic analogs, as well as the stilbenes, show promising activity against Gram-positive bacteria when at least one phenolic moiety is present, but not when absent. The potencies of the phenolic phenoxystyrenes and phenothiostyrenes were found to be comparable to those of the phenolic stilbenes tested.     

Mechanical waves in myelinated axons

Biomechanics and Modeling in Mechanobiology - The propagation of an action potential in nerves is accompanied by mechanical and thermal effects. Several mathematical models explain the deformation...     

Variation and frequency of cytokeratin polypeptide patterns in human squamous non-keratinizing epithelium

The squamous non-keratinizing epithelium of the human upper digestive tract was analyzed for keratin-like cytoskeletal proteins (cytokeratins) by both high resolution one- and two-dimensional gel electrophoresis. The Triton/high salt-insoluble portion of pure epithelial homogenates contains a number of SDS- and urea-extractable polypeptides, whose two-dimensional gel pattern (NEpHG/SDS) typically represents a defined subset of human cytokeratins. The cytoskeletal preparations of epithelial tissue samples obtained from different individuals were found to be uniform with respect to their content of cytokeratin polypeptides 55.0 kD/basic, 52.0 kD/acidic, and 49.0 kD/acidic. However, we have observed that four basic members of apparent molecular weight 60.0, 59.0, 56.5, and 56.0 kD occur at an inconstant rate. Consequently, the cytokeratin polypeptide patterns appeared highly variable as a result of the presence of constant plus compositionally different subsets of inconstant members. From the analysis of cytoskeletal portions of more than 300 individual tissue samples we demonstrate eight different keratin-like polypeptide patterns including their frequencies and propose the existence of no more than nine. These, most probably, encompass all the possible inter-individual variations to which the cytokeratins of this type of epithelium will combine for forming intermediate-sized filaments in vivo. We furthermore hypothesize that the observed variation of cytokeratin patterns may reflect a polymorphism of genes coding for the variable keratin-like polypeptide members.     

A versatile low-cost apparatus for cell electrofusion and other electrophysiological treatments

Instrumentation is described which will generate AC fields and DC square pulses for cell electrofusion, electroporation and other electrophysiological experiments. The equipment can generate a constant or intermittent AC field and a single square pulse, either alone or in combination. It can also generate a train of intermittent square pulses. The components for the instrumentation are commercially available and can be assembled by persons with little or no training in electronics. A design is given for a mass treatment chamber that can be easily constructed and viewed with a microscope.