Bacteriophage control of antiphagocytic determinants in group A streptococci.

At least two genes have been shown to be required for the expression of the antiphagocytic M protein molecule in group A streptococci. Evidence for phage involvement in the expression of M protein is that: (a) M- cultures of bacteria can be converted to the M+ state (resistant to phagocytosis) upon lysogenization with appropriate bacteriophages; (b) without those bacteriophages the M- recipient culture could not be detected to revert to the M+ state, even under our most stringent selective conditions; and (c) stable M+ lysogens cured of their bacteriophages returned to the M- state. Immunochemical analysis of lysogenically converted M+ strains demonstrated that they contain precipitating and antiphagocytic determinants of the parental M-76 strain (CS110) rather than M-12 determinants expressed by the phage donor strain.

Bright-flash electroretinography and vitreous hemorrhage. An experimental study in primates.

Serial, bright-flash electroretinograms (ERGs) were recorded from rhesus monkey eyes before and after a standard posterior penetrating ocular injury and injection of 0.5 mL of blood into the vitreous. This procedure resulted in a progressive depression to virtual nonrecordability of the ERG during a period of several weeks, owing to a combined progressive increase in optical density and loss of retinal function.

Pars plana vitrectomy infusion line in retinal detachment surgery.

We used new applications for a pars plana infusion cannula in three patients with retinal and choroidal detachments. Because the cannula maintained intraocular volume and form, it was helpful in treatment bullous retinal detachment and choroidal detachment.

A model of rural health care. Consumer response among users of the Marshfield Clinic.

Comparisons of prepaid, Medicaid and fee-for-service patients using the Marshfield Clinic and affiliated non-Clinic physicians indicate that a well-organized multispecialty group can successfully provide accessible and responsive care to rural populations and integrate varying types of payment systems. Most patients were highly satisfied, but differences in satisfaction among varying subgroups were substantially attributable to access barriers. Patients in the Greater Marshfield Community Health Plan (prepaied patients) were most generally satisfied, but patients using non-Clinic affiliates were higher on socioemotional satisfaction, reflecting certain barriers to personal care in complex organizational settings.

The Caloric Costs of Rope Skipping and Running.

Dr. Getchell has some disappointing news for fitness seekers who believe that jumping rope for ten minutes is equal to 30 minutes of jogging.

Hyaluronic acid capsule: strategy for oxygen resistance in group A streptococci.

Unencapsulated variants of encapsulated, M-protein-positive group A streptococci are oxygen sensitive and secrete inhibitory concentrations of hydrogen peroxide when grown in aerated broth cultures. The organisms were equally sensitive to hydrogen peroxide, and neither exhibited catalase or peroxidase activity, suggesting that differences in oxygen sensitivity reflect dissimilarity in oxygen uptake. The encapsulated parental culture was found to grow in aggregates that take up oxygen more slowly than unencapsulated, oxygen-sensitive derivatives.

Genetic variation in the M antigen of group A streptococci: reassortment of type-specific markers and possible antigenic drift.

The phylogenetic relationships of 73 strains of group A Streptococcus isolated over a six-year period from a population with a high prevalence of streptococcal infections were analyzed with use of four serotype-specific markers: the serum opacity factor (OF), the T antigen, the determinant of the M antigen that precipitates with antibody, and the M antiphagocytic determinant. OF inhibition tests divided the strains into five subtypes: a, b, c, d, and e. Strains within subtypes a, b, and c shared a previously unidentified M precipitin.

Training adaptations in skeletal muscle of juvenile diabetics.

Skeletal muscles from 12 male, juvenile-onset diabetics (JD) and 13 nondiabetics (ND) were studied to determine the effects of endurance training on mitochondrial enzyme activities, lipoprotein lipase (LPL) activity, and the oxidation of lipids (14C-palmityl CoA) in vitro. Ten weeks of endurance running (30 min/day, 5 days/wk) resulted in 11.0 and 12.

Histology of wound, vitreous, and retina in experimental posterior penetrating eye injury in the rhesus monkey.

We performed a histologic study to support our clinical observations on the mechanisms responsible for traction retinal detachment after a penetrating injury in the rhesus monkey eye. The monkey eyes (40 eyes; 40 monkeys) were characterized by intraocular fibrosis with the formation of a cyclitic membrane and epiretinal and subretinal membranes. The progression to a fibrous ingrowth from the wound occurred only in eyes with blood in the vitreous.

Method of production and natural history of experimental posterior penetrating eye injury in the rhesus monkey.

We developed an experimental model for a posterior penetrating eye injury that resulted in traction retinal detachment in 21 rhesus monkey eyes. The standard injury was an incision through the pars plana with vitreous prolapse and incarceration; the wound was then carefully closed with microsurgical techniques. At one to two weeks after injury, detachment of the posterior vitreous occurred and detachment of the retina occurred between seven and 11 weeks.

Experimental posterior penetrating eye injury in the rabbit. II. Histology of wound, vitreous, and retina.

The histological findings of the wound, the vitreous, and the retina in the rabbit eye with experimental posterior penetrating injury are described. Wound healing had just begun at 3 days after injury and was well established by 9 to 12 days. It involved proliferation of cells from the episclera and from the choroid.

Experimental posterior penetrating eye injury in the rabbit. I. Method of production and natural history.

A technique has been developed which produces an experimental posterior penetrating eye injury that reproducibly results in traction retinal detachment in rabbit eyes. The standard injury is an incision through the pars plana with vitreous prolapse and incarceration; the wound is then carefully closed with microsurgical techniques. It appears that blood in the vitreous is an essential factor in the development of vitreous traction and of traction retinal detachment.

Inhibition of alternative complement pathway opsonization by group A streptococcal M protein.

Group A streptococcal M protein is known to be antiphagocytic; however, the exact basis for this property has not been established. In this study the hypothesis was tested that cell wall--associated M protein inhibits phagocytosis by interfering with bacterial opsonization. Two strains of group A Streptococcus pyogenes, CS44 (M+) and CS64 (an M- variant of CS44), were radiolabeled, and after incubation in serum these organisms were exposed to human polymorphonuclear leukocytes.

A standardized estimator of the prevalence of alcoholism based on mortality data.

Death rates from alcohol-related causes correlated with over-all mortality and reflected general health conditions and demographic characteristics as well as the prevalence of alcoholism.

Physical characterization of ten R plasmids obtained from an outbreak of nosocomial Klebsiella pneumoniae infections.

Gentamicin resistance in Klebsiella pneumoniae involved in an outbreak at the Minneapolis Veterans Administration Hospital was due to a transmissible R plasmid. In addition to gentamicin, this plasmid conferred resistance to tobramycin, kanamycin, ampicillin, carbenicillin, cephalothin, chloramphenicol, and sulfathiazole. R plasmids which transferred this complex antibiogram were identified in several clinical isolates, including four different serotypes of K.

Nosocomial multiply resistant Klebsiella pneumoniae: epidemiology of an outbreak of apparent index case origin.

A nosocomial epidemic of multiply resistant (MR) Klebsiella pneumoniae characterized by resistance to gentamicin, tobramycin, kanamycin, cephalothin, chloramphenicol, and ampicillin occurred in a Veterans Administration hospital from 1975 to 1977. A total of 66 infected or colonized patients were observed in a 2-year period; there were 43 urinary tract infections, 13 wound or soft tissue infections, 8 pneumonias, and 6 patients with only asymptomatic stool colonization. Four patients had both pneumonia and a urinary tract infection.