Composition of the antigenic material removed from Campylobacter jejuni by heat

The antigenic material removed form Campylobacter jejuni by the boiling of whole cells in saline was examined biochemically. Analyses showed that the extracted material contained 3 micrograms of protein per ml per mg of wet cells and ca. 2.6 micrograms of carbohydrate per ml per mg of wet cells. Further extraction of the material with chloroform-methanol produced about 0.5 microgram of water-insoluble residue per ml per mg of wet cells, suggesting the presence of lipid as well. Additional analyses revealed the presence of hexose, pentose, heptose, hexosamine, and 2-keto-3-deoxyoctonic acid, and the extract was also positive by the Limulus amoebocyte lysate assay for lipopolysaccharide. An examination by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that at least 10 different protein bands could be detected. One of the major bands corresponded to the major outer membrane protein, as determined by comparison with an outer membrane protein preparation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Another major protein in the heated extract corresponded to a band previously shown to be flagellin. An analysis of the time course of the release of material showed that a significant amount was removed after 3 to 10 min at 100 degrees C, but the release of material seemed to be delayed at lower temperatures. These results show that the treatment of C. jejuni with heat produces a complex mixture of components, including cell wall lipopolysaccharide, the major outer membrane protein, and flagellin. It is likely that some cytoplasmic components are present as well. Blebs of outer membrane have been observed with this organism by electron microscopy. Our results confirm this and suggest that the heating of cells accelerates this blebbing process.     

Clinical and genetic features of variegate porphyria in a Chinese patient

Acute porphyria is rare in orientals. We describe a Chinese woman with recurrent generalised tonic-clonic seizures and abdominal pain. Genomic DNA studies identified a heterozygous base substitution from guanine to adenine at nucleotide position 503, resulting in substitution of arginine by histidine at position 168 of the protein (R168H). This genetic abnormality is similar to the mutation reported in Caucasians with variegate porphyria. To the best of our knowledge, this is the first report in the English literature a Chinese patient with variegate porphyria with an identifiable mutation. A brief review of porphyria is presented.     

Mechanisms of delta-hexachlorocyclohexane toxicity: II. Evidence for Ca2+-dependent K+-selective ionophore activity

delta-Hexachlorocyclohexane (delta-HCH) interacts with cardiac ryanodine-sensitive Ca2+ channels (RyR2), accounting in part for altered Ca2+ transients and contractility (reported in companion report). Analysis of channel gating kinetics in the presence of delta-HCH also revealed a nonfluctuating membrane current that remained even after RyR2 channels were blocked. We further elucidated the nature of a direct interaction between delta-HCH and biological membranes by measuring ionic currents across planar lipid bilayers made from defined lipids lacking cellular protein using voltage-clamp. Dimethyl sulfoxide, in the presence or absence of 50 microM gamma-HCH (lindane) or delta-HCH, produced negligible steady-state current with symmetric 100 mM CsCl in the range of +/-50 mV. However, the addition of 50 microM Ca2+ to the bilayer chamber in the presence of delta-HCH induced a profound increase in ionic permeability that was not seen in the presence of gamma-HCH or dimethyl sulfoxide control. Significantly, the permeability increase 1) was proportional with increasing Ca2+ to approximately 600 microM and saturated between 1 and 2 mM Ca2+ regardless of holding potential, 2) occurred only when delta-HCH and Ca2+ were added to the same side of the membrane, and 3) was independent of the order of addition or of the side of the membrane to which delta-HCH and Ca2+ was added. The Ca2+-dependent current produced by delta-HCH was highly selective for monovalent cations (K+ > Cs+ > Na+), with negligible conductance for Ca2+ or Cl-. In symmetric 100 mM K+, the conductance induced with 50 microM concentration each of delta-HCH and Ca2+ was 4.25 pA/mV. The results show that delta-HCH increases the ionic permeability of phospholipid membranes by two distinct Ca2+-dependent mechanisms: one mediated through RyR and the other mediated by a unique ionophore activity.     

Informal caregiving for frail older people at home and in long-term care institutions: who are the key supporters?

This paper describes the extent of the informal caregiving unit for older people who are physically or mentally frail living in private households or resident in long-term care institutions using cross-sectional analysis of survey data. A total of 1444 people aged 65 years or more registered with a general practitioner (GP) in four areas in England and, consenting to the study, were screened for mental or physical frailty. Of 1127 older subjects living at home 7% reported receiving no informal support, 15% had a paid supporter only and 78% nominated a key informal supporter who helped with defined activities of daily living of whom 650 (74%) were interviewed. Only 13% nominated more than one informal supporter. Key supporters were spouses (38%), daughters (30%), sons (9%), daughters-in-law (4%), other relatives (11%) and friends and neighbours (8%). Of 317 frail older people resident in long-term care institutions 175 (55%) received a main visitor at least once a week of whom 132 (75%) were interviewed. Main visitors were spouses (11%), daughters (36%), sons (23%), daughters-in-law (2%), other relatives (24%) and friends (4%). Qureshi & Walker's (1989) hierarchical, decision-making model for selecting informal caregivers was applied to the data and correctly identified 85% of key informal supporters and 79% of main visitors interviewed. This large-scale comprehensive survey of informal care for frail older people supports earlier small-scale localized studies highlighting the key role of spouses and daughters in the provision of informal support. Families of frail older people provide the support to maintain people at home.     

Experimental approach to the pathogenesis of the anomalies of amniotic disease

By intra-adnexal injection of glucose in the rabbit embryo, we were able to stimulate all the anomalies associated with "Amniotic Disease". Since we were even able to obtain amniotic bands, this study provides an excellent experimental model of this disease. Resulting lesions occur early in development, corresponding to the first trimester of human gestation. All of the anomalies can ultimately be explained by the destruction of the most superficial cells: epiblastic cells of the embryo and the amnion, subjacent mesenchyme, and endothelial cells. The subsequent lack of interaction between these cells and the importance of the anatomical localizations of resulting hematomas can lead to the pathogenetic approach to this disease. In light of the present study, the disease appears to be caused by an external factor within the amniotic fluid. The exact nature of the destructive agent(s) remains a mystery in man.     

Fatty acid composition of the human macula and peripheral retina.

The fatty acids in the human retina and the macular region were measured quantitatively (mole percent) by gas chromatography. The major fatty acids of the human retina and macula were palmitic, stearic, oleic, arachidonic, and docosahexaenoic. Surprisingly, there was much less docosahexaenoic acid in the macular region (15.9% of total) than in the peripheral retina (22.3% of total). There was a group of "other fatty acids," not any of the five major fatty acids, that were relatively more abundant in the macula (21.0% of total) than in the peripheral retina (10.7% of total). These results indicate that the human macula has a unique biochemical composition, which differs substantially from the peripheral retina. Establishment of the biochemical composition of the macula may be important for helping recognize possible changes associated with diseases such as age-related macular degeneration.     

Lasthénie de Ferjol syndrome. Apropos of a case]

After a brief review of literature, the authors report a case of the "Lasthénie de Ferjol" syndrome. From clinical observations, they establish theoretical landmarks and underline the necessity for searching the meaning.