Cholesterol is an essential component of the cell, but excessive blood levels are a major risk factor for the development of atherosclerotic plaques that can lead to heart disease and stroke, the foremost cause of premature death in Western societies. Policosanol, a mixture of very long chain alcohols derived from sugarcane, has gained considerable attention among the public as safe and effective means to reduce blood cholesterol levels, a belief based on some early clinical studies. My research investigates one possible mechanism by which policosanol might decrease blood cholesterol levels: the inhibition of cholesterol synthesis in the liver. Previous studies with cultured hepatoma cells have indicated that policosanol suppresses HMG-CoA reductase activity, the regulatory step in cholesterol synthesis, by activation of AMP-kinase, which then inactivates HMG-CoA reductase by phosphorylation. My studies have confirmed this activation of AMP-kinase both in hepatoma cells and in whole animals after intragastric administration of policosanol. The present studies were also undertaken to identify the upstream signaling mechanism by which policosanol activates AMP-kinase. Treatment of rat hepatoma cells with policosanol increased the amount of phosphorylated CaMKK, which can directly activate AMP-kinase, but had only a small effect on LKB1, the principal activator of AMP-kinase. Intragastric administration to mice similarly activated CaMKK, but not LKB1, in the liver. To determine if metabolism of policosanol was necessary for activation of AMP-kinase, siRNA-mediated suppression of fatty aldehyde dehydrogenase, fatty acyl CoA synthase-4, or β-ketothiolase in hepatoma cells prevented the phosphorylation of AMP-kinase and HMG-CoA reductase by policosanol, indicating that metabolism of these very long chain alcohols to fatty acids and subsequent peroxisomal β-oxidation is necessary for the suppression of cholesterol synthesis. As the principal product of fatty acid -oxidation is acetyl-CoA, further studies demonstrated that addition of acetate to cells similarly activated AMP-kinase and inactivated HMG-CoA reductase. This finding argues that the activation of AMP-kinase by policosanol results from the generation of excess acetyl-CoA via peroxisomal metabolism. Finally, although the intestine is a significant source of circulating cholesterol, policosanol was unable to activate AMP-kinase in the small intestine. These findings open new perspectives for the control of cholesterol synthesis by activators of AMP-kinase.

A retrospective study of invasive pneumococcal disease in patients from Greater Göteborg in 1964- 1980 identified 125 cases of meningitis, 305 of pneumonia, 61 of septicemia with unknown focus, and 17 with other manifestations, all verified by cultures from normally sterile body fluids. The incidence was several times higher in infants and in the elderly than in any other age-group. A wide variety of underlying conditions were present in 23% of the infants, 34% of the children, and 81% of the adults. In adults alcoholism was known in one third of the cases. The case fatality rate was 24% among patients with underlying conditions and 9% among previously healthy individuals. The case fatality rate was 50% in patients with hospital-acquired infection. Twohundred-fifteen pneumococcal strains, isolated from blood or CSF from 1971 to 1983 at the laboratories of clinical bacteriology of Göteborg, Malmö, and Umeå were serotyped by coagglutination (COA). Of all isolates, 89% belonged to serotypes represented in the 23-valent vaccine. In a separate study COA was compared with counterimmunoelectrophoresis (CIE). COA was found to have several advantages; rapidity, lower cost, and ability to disclose serotypes with neutral charge, which constituted 19% of all strains. In a prospective study the etiology was determined in 196 hospitalized patients with pneumonia, most of them community-acquired. Culture of specimens from blood, transtracheal aspirate (TTA), sputum, and nasopharynx, assays of antigen in sputum, urine, and TTA, and assays of pneumococcal antibodies to capsular polysaccharide, C-polysaccharide, and pneumolysin in paired sera were performed. The etiology was established in 64% of the patients. Streptococcus pneumoniae was the most common agent (32%). In a serological study of patients with pneumococcal infection, diagnosed by culture of CSF, TTA, or blood, IgG antibodies against C-polysaccharide and pneumolysin were determined by ELISA. The diagnostic sensitivity was only 51% and 60%, respectively. In conclusion, invasive pneumococcal disease is strongly overrepresented at tender and high age and in patients with concomitant conditions, notably alcoholism. S. pneumoniae remains a predominant causative agent of community-acquired pneumonia in adults needing hospitalization. Due to the low sensitivity and/or specificity of individual microbiological techniques, a combined use of several techniques is necessary when trying to assess the relative importance of pneumococci and other agents in pneumonia. Extended use of the currently available pneumococcal vaccine and development of improved pneumococcal vaccines seem highly warranted. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1993, härtill 5 uppsatser.</p> / digitalisering@umu.se

Evidence suggests that there is an immunological response of the recipient to xenograft bioprosthetic heart valves. Information on the impact of HMG-CoA reductase inhibitors (statins) and their anti-inflammatory properties on bioprosthetic valve failure remains limited. We sought to examine the efficacy of statin therapy in a rodent model of bioprosthetic valve implantation. To mimic the human scenario, fresh or glutaraldehyde-fixed aortic valve root conduits from Lewis rats or Hartley guinea pigs were microsurgically implanted intravascularly into the infra-renal aorta of Lewis rats. The syngeneic control group consisted of a fresh rat valve conduit implanted into a rat. The xenogeneic control group consisted of a glutaraldehyde-fixed guinea pig valve conduit implanted into a rat. Treatment groups consisted of xenogeneic groups treated with either daily steroids or statins. Overall, steroid treatment attenuated the inflammatory response observed within the xenogeneic glutaraldehyde-fixed valve conduits. Treatment with statins did not decrease this inflammatory response.

Methylmalonic aciduria results from defects in the enzyme methylmalonyl-CoA mutase and from defects in the synthesis of the enzyme's cofactor adenosylcobalamin. Two patients who excrete methylmalonic acid have been shown to have a homozygous nonsense mutation in the methylmalonyl-CoA epimerase gene (MCEE). To further understand the causes of methylmalonic acid excretion, the MCEE gene was sequenced in 229 patients who excreted methylmalonic acid for which no cause was known. Mutations were detected in five patients. Fusion of fibroblast lines from two patients with a homozygous nonsense mutation in MCEE did not result in correction of [14C]propionate incorporation toward control values while the defect in these fibroblasts was complemented by mut, cblA, and cblB fibroblasts. Transfection with wild-type MCEE cDNA resulted in correction of the biochemical phenotype in cells from both patients. These experiments support the hypothesis that a defective epimerase enzyme can be a cause of elevated methylmalonic acid excretion.

Tuberculosis, caused by the pathogenic bacteria Mycobacterium tuberculosis, is one of the most widespread and deadly infectious diseases today. Treatment of tuberculosis relies on antibiotics that were developed more than 50 years ago. These are now becoming ineffective due to the emergence of antibiotic resistant strains of the bacteria. The aim of the research in this thesis was to develop new antibiotics for tuberculosis treatment. To this end, we targeted enzymes from two essential biosynthetic pathways in M. tuberculosis for drug development. The methylerythritol phosphate (MEP) pathway synthesizes a group of compounds called isoprenoids. These compounds have essential roles in all living organisms. The fact that humans utilize a different pathway for isoprenoid synthesis makes the MEP pathway enzymes attractive targets for drug development. We have determined the structures of two essential enzymes from this pathway by X-ray crystallography: 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) and 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (IspD). These are the first structures of these enzymes from M. tuberculosis. Additionally, structures of the IspD enzyme from the related bacteria Mycobacterium smegmatis were determined. We have characterized these enzymes and evaluated the efficiency of a number of inhibitors of the DXR enzyme by biochemical methods. Crystal structures of DXR in complex with some of these inhibitors were also determined. The second pathway of interest for drug development is the universal pathway for Coenzyme A biosynthesis. Enzymes in this pathway have essential roles in all living organisms. However, the bacterial enzymes have little similarity to the human homologues. We have determined a number of structures of the M. tuberculosis pantothenate kinase (PanK), the regulatory enzyme of this pathway, in complex with two new classes of inhibitory compounds, and evaluated these by biochemical methods. The structures and biochemical characterization of these enzymes provide us with detailed information about their functions and broadens our knowledge of these bacteria. Biochemical and structural information about new inhibitors of these enzymes serve as a starting point for future development of antibiotics against tuberculosis.

Thesis (Ph. D.)--Case Western Reserve University, 2007. / [School of Medicine] Department of Neurosciences. Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: 100-110.

Thesis (Ph.D. in Epidemiology) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 83-102).

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains ix, 175 p. : ill. Includes abstract. Includes bibliographical references.