The origin of phospholipids of the enveloped bacteriophage phi6

The phospholipid class and molecular species compositions of bacteriophage phi6 and its host Pseudomonas syringae were determined quantitatively using TLC and liquid-chromatography/electrospray ionization mass-spectrometry. In addition, the fatty acid compositions of the phospholipids were analyzed by gas-chromatography/mass-spectrometry. The phage contained significantly more phosphatidylglycerol (PG) and less phosphatidylethanolamine (PE) than the host cytoplasmic (CM) and outer (OM) membranes. In addition, the phospholipid molecular species composition of the viral membrane differed from those of the host membranes, but resembled that of CM more than OM as shown by principal component analysis (PCA). The membrane of phi6 contained more 34:1 and 34:2, and less 32:1 PE and PG molecular species than the host CM or OM. Also, phi6 contained negligible amounts of saturated phospholipid molecular species. These data provide the first biochemical evidence suggesting that phi6 obtains its lipids from the CM. This process is not unselective, but certain phospholipid species are preferentially incorporated in the phage membrane. Common factors leading to similar enrichment of PG in every membrane-containing bacterial virus system studied so far (phi6, PM2, PRD1, PR4, Bam35) are discussed.     

Adhesion of soluble fibronectin,vitronectin, and collagen type IV to intraocular lens materials

PURPOSE: To evaluate soluble fibronectin, vitronectin, and collagen type IV adhesion to poly(methyl methacrylate) (PMMA), fluorine-surface-modified PMMA, silicone, hydrophobic and hydrophilic acrylate, and hydrogel intraocular lenses (IOLs) and determine whether hydrophobic and hydrophilic acrylate materials have different fibronectin-adhesion properties. SETTING: Department of Medical Biochemistry, University of Oulu, Oulu, Finland. METHODS: One hundred fifty IOLs were incubated for 1 week at 37 degrees C with radioactive-iodine-labeled soluble fibronectin, vitronectin, or collagen type IV. Fifty IOLs were analyzed for each protein, 5 from each of 10 different IOL models (PMMA, Alcon MC60BM; fluorine-surface-modified PMMA, Chiron Fluorilens Centra-55F; silicone, Allergan Medical Optics SI-40NB and Pharmacia and Upjohn CeeOn 911A; hydrophobic soft acrylate, Alcon AcrySof MA60BM and SA30AL and AMO Sensar; hydrophilic soft acrylate, Ioltech Stabibag and Bausch and Lomb BL27; and hydrogel, Bausch and Lomb Hydroview. The amount of adherent protein was measured with a gamma counter at 1 and 7 days and expressed as counts per minute. RESULTS: At 1 week, significantly more fibronectin was bound to the hydrophobic acrylate IOLs than to the 2-hydroxyethyl methacrylate (HEMA) containing hydrophilic acrylate IOLs (P <.05 to.0001). Significantly more vitronectin was bound to the 2 silicone IOLs than to any other IOL (P <.01 to.0001) at 7 days. Collagen type IV adhered best to the hydrophilic acrylate IOLs, which were significantly different (P <.01 to.0001) than the other IOLs at 1 and 7 days. CONCLUSIONS: Each IOL material had a different affinity to each protein. Significant binding to 1 protein does not indicate that the IOL will bind significantly to all proteins; instead, each protein should be studied separately. Fibronectin bound significantly better to hydrophobic acrylate IOLs than to hydrophilic acrylate IOLs, suggesting that the HEMA-containing IOLs should be classified with the hydrogel IOL group.     

Alternative materials to improve total hip replacement tribology

An improvement in tribology of bearing surfaces is an effective means of increasing the longevity of total hip replacement (THR). Currently, 3 approaches are available to achieve this aim: first, use of highly cross-linked UHMWPE; second, aluminum oxide ceramic bearings, and third, metal-on-metal bearings. Cross-linking reduces the wear resistance of UHMWPE markedly without impairment of other significant properties of the material. Simulator studies and some clinical long-term (10-22 years) follow-up surveys suggest an almost immeasurable wear of the highly cross-linked UHMWPE-based acetabular components during an expected clinical life span. Bioinert alumina ceramic (aluminum oxide) was introduced 3 decades ago for THR-bearing surfaces to improve performance and longevity. Alumina ceramic is entirely biostable and bioinert and has good mechanical properties. For correctly positioned alumina-on-alumina bearings, the annual linear wear rate has been reported to be 3.9 microm. Alumina heads have been successfully used in combination with polyethylene sockets, but as regards wear, the best results have been obtained with alumina-on-alumina bearings. In ceramic THR bearings, precise manufacture and contact surface geometry, including optimal clearance, are most important. For the currently available products, the component fracture risk is almost nonexistent (less than 1 per 1000). Metal-on-metal bearings were used in the early stage of THR surgery, although not all old designs were successful. More recent analyses of the early series have shown the advantages of metal-on-metal to be better and have led to a renaissance of this articulation. Initially, stainless steel was used because it was easy to manufacture and polish. Current metal-on-metal bearings are based on cobalt-chromium-molybdenum alloys with varying carbon contents. Such bearings are self-polishing. Linear wear rates remain at the level of a few microm a year. An improvement in technology has increased the life span of the above three THR-bearing systems. Although the technical solutions differ considerably, they all seem to improve clearly the tribology and longevity of the THR. Each of these bearing concepts will probably permit the use of larger head sizes, to reduce the risk of impingement and luxations.     

Effects of Aroclor 1242 and different fish-based diets on vitamins A1 (retinol) and A2 (3,4-didehydroretinol), and their fatty acyl esters in mink plasma

The effects of a 21-week exposure to Aroclor 1242 (1mg per day in feed) on plasma concentrations of vitamins A(1) (retinol) and A(2) (3,4-didehydroretinol) and their principal fatty acyl esters (A(1)-16:0, A(2)-16:0 (palmitates), A(1)-18:1n-9; A(2)-18:1n-9 (oleates), and A(1)-18:0; A(2)-18:0 (stearates)) were studied in young female mink (Mustela vison) fed a diet based on freshwater smelt. These vitamin levels were also examined in mink fed diets containing Baltic herring or fatty marine fish. In the Aroclor-exposed smelt-fed mink, the plasma concentrations of A(1) and A(2) esters were significantly lower than the levels in controls fed the uncontaminated smelt diet. In addition, the A(2) esters reacted more sensitively to the polychlorinated biphenyls than did A(1) esters. In contrast, in the plasma of the exposed mink the level of alcoholic A(1) was normal, and transport of thyroxine (T(4)) and nonspecific lipoprotein transport of major lipids were not impaired. Despite the large dietary supply of vitamin A(2) and high levels of plasma A(2) esters, the mink fed freshwater smelt had only trace amounts of alcoholic vitamin A(2) in their plasma. The concentrations of A(1) and A(2) esters in the plasma of all the mink studied correlated with the hepatic total concentrations of the vitamins. Thus, in carnivores that have nonspecific lipoprotein transport of vitamin A esters, determination of plasma levels of the esterified vitamins may be a useful nondestructive way to estimate stores of the vitamin A analogs in the body and to assess the organochlorine-induced decrease in the vitamin stores.     

DEMENTIA IN PARKINSON'S DISEASE

The occurrence of dementia in patients with Parkinson's disease was studied in a Parkinsonian population consisting of all traceable patients residing in a defined area. the prevalence of dementia was found to be 29 per cent in 444 patients studied. the frequency of dementia increased with advancing age and the patients showing signs of clinical arteriosclerosis were more often demented than the patients without arteriosclerosis. There was, however, an evident association between the stage of the disease and the frequency of dementia. the most severely disabled patients displayed dementia more often than the mildly affected, both among the patients with and without arteriosclerosis. the demented patients showed significantly more severe rigidity and hypokinesia when compared with the non-demented. Increasing severity of rigidity and hypokinesia, in particular, was found to have a positive correlation with the degree of dementia. the association between dementia and the degree of motor involvement is considered to suggest the role of subcortical structures in the pathophysiology of dementia in Parkinson's disease.     

Long-term effect of pharyngeal flap surgery on craniofacial and nasopharyngeal morphology in patients with cleft palate

The craniofacial morphology of 48 consecutive adult males with isolated cleft palate was studied by means of lateral cephalograms at the mean age of 18.8 years. Twelve of the patients had received pharyngeal flap surgery between 4 and 12 years of age (mean age 6 years) to improve speech. No significant differences were noticed in craniofacial cephalometric relations between the patients who had not had velopharyngeal flap surgery (VPF-) and those who had (VPF+), although the latter showed a tendency toward a more vertical growth direction. In the pharynx, the VPF+ group showed larger sagittal depths of nasopharyngeal airway but smaller depths of oropharyngeal airway. The differences were significant at the levels of the upper nasopharynx and lower oropharynx. According to the hospital records, none of the patients demonstrated persistent airway obstruction. Cephalometry may be useful in evaluating the changes in pharyngeal airway dimensions that may be related to velopharyngeal flap surgery.     

Lipid-lowering response to statins is affected by CYP3A5 polymorphism

Individuals expressing the polymorphic CYP3A5 enzyme might show a more than average efficiency in the metabolism of lovastatin, simvastatin and atorvastatin. We studied whether the expression of CYP3A5 is associated with an impaired lipid-lowering response to statins in 69 Caucasian patients. Lovastatin, simvastatin and atorvastatin were significantly less effective in CYP3A5 expressors than in non-expressors. The mean serum total cholesterol concentration at 1 year was 23% higher (P = 0.0014) and the mean serum low-density lipoprotein cholesterol concentration was 24% higher (P = 0.036) in subjects possessing the CYP3A5*1 allele (CYP3A5 expressors, n = 7) than in subjects homozygous for the CYP3A5*3 allele (non-expressors, n = 39). The mean percentage reduction in serum total cholesterol from baseline was significantly smaller in CYP3A5 expressors than in non-expressors (17% versus 31%, P = 0.026). No association between hypolipidemic efficacy and CYP3A5 polymorphism was observed among 23 subjects taking statins that are not dependent on CYP3A5 (fluvastatin, pravastatin). These findings suggest that CYP3A5 may be a genetic determinant of interindividual differences in response to certain statins.