Determination of site of infection in endocarditis

Medical-surgical treatment of antibiotic refractory endocarditis requires determination of the site of infection, which is not always possible with conventional cardiac catheterization. The cases of two patients with right-sided endocarditis who survived after combined medical-surgical therapy are presented. One had persistent Pseudomonas aeruginosa bacteremia and three possible sites of infection. Multiple quantitative blood cultures proximal and distal to each suspected site indicated the pulmonary valve alone was infected. The second had sustained bacteremia with three enteric organisms and no apparent valvular abnormality. Quantitative cultures excluded the abdomen as the continuing source of bacteremia and suggested the tricuspid valve was infected. This was confirmed by a second catheterization using multiple cultures in conjuction with dye dilution studies, intracardiac phonocardiography, and angiography. These bacteriologic and cardiologic techniques may be especially useful in detecting right-sided endocarditis and may also be helpful in detecting concomitant infection of both sides of the heart.

Rapid onset of hyporesponsiveness to interferon induction on re-exposure to polyribonucleotide

Only doses of complexed polyriboinosinic: polyribocytidylic acids sufficient to induce interferon, stimulated hyporesponsiveness to re-induction in rabbit kidney cells. Results of experiments designed to delineate the earliest time of appearance of hyporesponsiveness suggested the time of onset was less than i h after the end of a i h exposure to the inducer. The duration of hyporesponsiveness was about 24 h. Interferon itself did not produce hyporesponsiveness. Hence hyporesponsiveness must be related to an event or a substance synthesized before interferon production. The best candidate is a control protein inhibiting interferon production which is rapidly synthesized following exposure to an inducer.

Adhesive tape: potential source of nosocomial bacteria

During a 7-day period, a variety of bacteria, including opportunistic ones, were recovered from 23 rolls of adhesive tape being used in a 16-bed intensive care unit. All rolls of tape were sterile when received from the manufacturer. Mixed flora was recovered from a total of 15 rolls, whereas eight rolls yielded pure cultures. Organisms recovered included Staphylococcus aureus, Pseudomonas aeruginosa, and various species of Enterobacteriaceae. Although no illness or infection arising directly from contaminated adhesive tape has been documented, we feel that a potential source of infection has been identified. Most important is the fact that such tape may contaminate the hands of personnel who handle it. Also, the adhesive tape may directly contaminate a patient since it is widely used to secure artificial airways and various drainage tubes which results in the tape coming into close contact with the mucous membranes lining the patient's respiratory and urogenital tracts.

Interferon administered in the cerebrospinal space and its effect on rabies in rabbits

Because combined administration of intramuscular and intravenous interferon has been partially successful in the incubationary treatment of rabies, the effect of direct interferon administration into the cerebrospinal fluid space was tested. After injecting 1,800 U of interferon into the cisterna magna or the lateral ventricle, periodic samples, obtained by cisternal taps, showed that 1 to 5% remained after 24 h, as opposed to the known clearance of interferon from the bloodstream to this level within minutes. The distributions of interferon and (131)I-labeled albumin were similar as demonstrated by kinetics of clearance monitored over 24 h. Beginning with and after experimental infection of rabbits, daily intraventricular injections of one million units of interferon were given for as long as 3 weeks. Interferon was prepared from cell culture fluids after pressure dialysis and chromatography on Sephadex G-100. This intensive treatment did not prevent encephalitis, but prolonged the length of the incubation period by one- to two-thirds. The outcome after intraventricular administration was not as favorable as when one million units equally divided between intramuscular and intravenous injections were given at the time of challenge. Interferon administered in the subarachnoid space in this fashion is apparently inadequate to protect the rabbit against rabies. Its role as an adjunct measure, or other methods of administration in the nervous system, remains to be examined.

Effect of Aging of Serum on Quantitation of Complement Component C3

Concentrations of the third component of complement (C3, β1C globulin) in serum may vary considerably in patients with certain diseases. Its accurate measurement is therefore important medically. For some time it has been recognized that the C3 in serum stored at room temperature breaks down into two proteins, β1A and α2D. Monospecific antisera have been made to the three antigenic determinants of C3, designated A, B, and D. An anti-C3 supplied commercially is monospecific for the A determinant, which is shared by C3 and its breakdown product β1A. With C3 breakdown and formation of β1A, depletion of antibody to the A determinant is increased to 1.6 times the depletion by native C3. Therefore, the previous history of a serum can affect the "apparent" concentration of C3, with values spuriously increased to a variable degree, in serum that has been stored. The effect of time, temperature, and conditions of storage on this increase are discussed.

A histochemical study of the developing tibiotarsus in Malathion-treated chick embryos

Chick embryos were exposed to a teratogenic dose of Malathion at 5 days of incubation. The treated tibiotarsi developed micromelia, an asymmetrical deposition of bone spicules, and sites of reduced matrix within the cartilage model. The major histochemical differences occurred in the areas of reduced cartilage matrix. These included a reduction in sulfated mucopolysaccharide and ribonucleic acid content and an increased glycogen storage. Calcification was more extensive in the treated tissues and premature centers of mineralization appeared within the epiphyses. Alkaline phosphatase was associated with sites of ossification and calcification and was, therefore, more extensively distributed in the treated tissues.

Histogenesis of the tibiotarsus in malathion-treated chick embryos

Chick eggs were injected with 0.1 ml of 2% Malathion in corn oil on the 5th day of incubation, and its effect on skeletogenesis, particularly the development of the tibiotarsus, was studied throughout the incubation period. Anatomically, the treated embryos showed a generalized reduction in body size, delayed patterns of mineralization in certain of the endochondral bones, and micromelia. The treated tibiotarsi consistently exhibited a reduced growth rate and an angulation at the junction of the diaphysis and distal epiphysis. The rate of periosteal ossification, cartilage resorption, and marrow cavity formation progressed more rapidly in the tibiotarsi of the treated embryos. The striking feature of the treated tibiotarsi was degenerative necrosis of the cartilage within both proximal and distal epiphyses. This necrotic zone exhibited a reduced matrix and progressive degeneration of the chondrocytes.

Regulation of cellular interferon production: enhancement by antimetabolites

Cycloheximide, at a protein-inhibitory concentration, when given to rabbit kidney cell cultures that had been exposed either to UV-irradiated Newcastle Disease virus or to a complex of polyinosinic and polycytidylic acids (poly I.poly C), enhanced the production of interferon. The enhancement was greater if, in addition to cycloheximide, the cells were also treated with actinomycin D. On the basis of these findings, a mechanism, consisting primarily of the production of a control protein which normally checks interferon production, is postulated for interferons stimulated by these two substances.

Characterization of virus- and endotoxin-induced interferons obtained from the serum and urine of rabbits

Interferons induced in the rabbit by Newcastle disease virus or by endotoxin have been further characterized as to their physicochemical stability and molecular size by Sephadex G-100 gel filtration. Endotoxin-induced interferon obtained from serum was more labile than virus-induced interferon. Both endotoxin and virus induced interferons obtained from serum contained two peaks: a minor high molecular weight (>100,000) peak and a major lower molecular weight peak. The molecular weight of the major peak induced by endotoxin was 54,000, and that induced by Newcastle disease virus was 46,000. The gel filtration pattern of interferon recovered from the urine of animals inoculated with virus reflected faithfully the pattern found in serum except that there was proportionately less of the high molecular weight peak. However, the urine interferon from endotoxin-inoculated animals contained only one broad peak with a molecular weight of 35,000. This was not the peak fraction present in the serum of such animals. It is postulated that this may represent the basic unit of endotoxin-induced interferon, and that the serum components are either polymers or conjugates of this basic unit.