The role of encapsulation in the pathogenesis of anaerobic gram-positive cocci

The pathogenicity of 22 anaerobic and facultative Gram-positive cocci (AFGPC) was investigated by inoculating them into mice and determining their ability to cause subcutaneous abscesses. Only 11 heavily encapsulated isolates (greater than 50% of the cells were encapsulated) induced abscesses. However, when the other 11 isolates were injected with Bacteroides sp. or facultative and aerobic bacteria, abscesses were formed in 8 of the 11 combinations. The AFGPC recovered from the mixed infections contained many encapsulated cells. Encapsulation also occurred in cocci injected with capsular material or with Formalin-killed cells of Klebsiella pneumoniae or capsule-positive Bacteroides sp. After acquisition of capsules, these strains could induce abscesses on reinoculation in mice.     

Regional localisations and linkage relationships of seven RFLPs and myotonic dystrophy on chromosome 19

Summary We have studied the genetic linkage relationships of seven DNA polymorphisms on chromosome 19, with each other and with the myotonic dystrophy locus. The DNA sequences were localised to various regions of the chromosome using translocations in somatic cell hybrids. These results provide the basis for a linkage map of most of chromosome 19, and suggest that the myotonic dystrophy locus is close to the centromere.     

Further observations on the effect of air ions on influenza in the mouse

In earlier papers we reported that the course of respiratory infections in mice produced by intranasal instillation of measured amounts of: (1) a fungus, COCCIDIOIDES IMMITIS, (2) a bacterium, KLEBSIELLA PNEUMONIAE and (3) a virus, PR8 strain of influenza virus was materially affected by the air ion environment. When the challenge dose of influenza virus was administered as an aerosol, as described here, the cumulative mortality rate was completely uninfluenced by shifts in the concentration of positive and negative air ions in the ambient atmosphere and by the accompanying electrical fields. A hypothetical mechanism accounting for the different results obtained with intranasal and aerosol challenge is presented.

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Zusammenfassung In früheren Arbeiten wurde über den Verlauf von Infektionen der Atemwege von Mäusen nach intranasaler Instillation bekannter Mengen (1) des Fungus COCCIDIOIDES IMMITIS, (2) KLEBSIELLA PNEUMONIAE und (3) PR8 Influenzavirus berichtet, die durch Luftionen beeinflusst waren. Hier wurde die Dosis von Influenzavirus als Aerosol verabreicht. Die kumulative Mortalitätsrate wurde durch den Wechsel der Konzentrationen von positiven und negativen Luftionen in der Umgebungsatmosphäre und begleitenden elektrischen Feldern nicht beeinflusst. Eine Erklärung für die unterschiedlichen Ergebnisse bei intranasaler und Aerosol-Virusapplikation wird diskutiert.

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Resume Dans des travaux précédents, on a montré que l'évolution de maladies du système respiratoire provoquées chez des souris par l'instillation intranasale de doses déterminées d'agents pathogènes était affectée de façon significative par le taux d'ionisation de l'air ambiant. Il s'agissait d'agents cryptogamiques (COCCIDIOIDES IMMITIS), bactériens (KLEBSIELLA PNEUMONIAE) et de virus (lignée PR8 du virus de la grippe). Lorsque la dose minimum de virus grippal est appliquée sous forme d'aérosole — selon la méthode décrite ici — le taux cumulatif de mortalité n'est aucunement influencé par les variations de concentration d'ions positifs ou négatifs de l'air ambiant ni par les champs électriques qui les accompagnent. On développe une hypothèse pour expliquer la diversité des résultats obtenus au moyen des infectations intranasales ou par aérosoles.

     

Low-density lipoprotein derived from atherosclerotic patients enhances macrophage cholesterol accumulation and in vitro platelet aggregation

The aims of our study were to assess the differences between plasma lipoproteins separated from five angiographically normal subjects and five patients with proven CHD. The patients with CHD had significantly higher levels of LDL-cholesterol and apo-B, and reduced levels of HDL-cholesterol and apo-Al. The biological characteristics of LDL and HDL from both groups of patients demonstrated that the LDL from the CHD patients enhanced platelet aggregation and increased cholesterol content and cholesterol esterification in MPM compared to the normal patients. HDL had no significant effect on MPM; however, there was an increased platelet aggregation with HDL derived from the CHD patients, while the HDL from the normal group decreased platelet aggregation. The data suggest that lipoproteins isolated from CHD patients are more atherogenic than lipoproteins from normal patients.     

Randomised controlled trial of lymphoblastoid interferon alfa in Europid men with chronic hepatitis B virus infection.

OBJECTIVE--To confirm the findings of pilot studies that interferon alfa is an effective treatment of Europid men with chronic hepatitis B virus infection. DESIGN--Randomised controlled trial of three months treatment with interferon alfa followed by 12 months of observation. SETTING--Outpatient clinic of a tertiary referral centre. PATIENTS--37 Treated men (six anti-HIV positive) and 34 untreated men (nine anti-HIV positive) who met the criteria for the trial. Four controls failed to complete follow up. INTERVENTIONS--The treated group received subcutaneous injections of 5-10 MU interferon alfa/m2 daily for five days, then 10 MU/m2 thrice weekly for 11 weeks. Follow up continued at monthly intervals for 12 months. Untreated controls were monitored over the same period. MAIN OUTCOME MEASURE--Hepatitis B e antigen and hepatitis B virus DNA state after 15 months of observation. RESULTS--12 Of the 37 treated patients cleared hepatitis B e antigen and hepatitis B virus DNA, whereas only one of 30 untreated controls seroconverted over the same period--an increased response rate of 29% (95% confidence interval 13% to 45%). The life table estimate of response at 15 months was 35% in treated patients, an increase of 32% above controls (95% confidence interval 16% to 48%). The response rates in groups by predictive pretreatment variables were 12 of 31 anti-HIV negative patients (excess response 34%; 95% confidence interval 14% to 54%), 12 of 26 with chronic active hepatitis before treatment (excess response 46%; 27% to 65%), and 12 of 21 with a pretreatment serum aspartate aminotransferase activity greater than 70 IU/l (excess response 46%; 16% to 76%). The combination of these factors predicted response with a sensitivity of 100% and a specificity of 80%. Four of the 12 responders, who had all been infected for less than two years, also lost hepatitis B surface antigen. Treatment was well tolerated. CONCLUSIONS--Interferon alfa is effective in the treatment of a proportion of Europid men with chronic hepatitis B virus infection, who might be identified before treatment. Additional strategies are required to improve the rate of response.