Morphological, chemical and antigenic characterization of M-1 N-acetylmuramidase-digested cell walls of the oral pathogenic bacterium Actinomyces viscosus T14V and T14AV.

The cell walls were enzymically solubilized with M-1 N-acetylmuramidase. The minimum amount of enzyme required for maximum response was 70 micrograms/mg of wall. The action of the enzyme seemed localized, producing holes in the wall structure. Chemistry and morphology suggested that all of the wall was solubilized. Antigenically, anti-T14AV formed precipitates with 11-14 antigens from the solubilized walls, of which 3 are unique to strain T14AV. Many of these antigens have not been observed previously due to the physical and/or chemical degradation associated with the extraction procedures. Antisera prepared against strain T14V whole cells formed precipitates with only a few antigens common to both strains. The results suggest that immunological processing and/or surface localization of these antigens are different.

The mitogenicity for murine splenocytes of specific surface components of the oral periodontopathic bacterium, Actinomyces viscosus.

Many characterized fractions obtained from A. viscosus were examined to identify the macromolecules responsible for mitogenicity for lymphocytes. Spleen-cell suspensions of CBA/J mice were cultured with 50-200 micrograms dry weight of A. viscosus strains T14V and T14AV cellular components. Lipopolysaccharide (LPS) (Escherichia coli) was used as a positive control. Mechanical disruption with a French pressure cell or sonication produced preparations with a stimulation of 69,082 and 45,183 counts above background (CAB), respectively. Mitogenic activity was also present in the culture supernatant (38,000 CAB). Other poorly mitogenic fractions included the peptidoglycan, cell-wall fractions, muramidase digests of cell walls, and the microcapsule extracted from whole cells with 0.5 M MgNO3. The results suggest that mitogenic activity is not associated with the isolated cell-wall structure. The activity was released from the cell surface by physical shearing forces, as well as released into the medium growth.

Breast cancer diagnosis and survival in women with and without breast implants.

The stage at diagnosis and the survival experience of 41 women who developed breast cancer after cosmetic breast augmentation were compared with those of all other patients with breast cancer (n = 13,246) diagnosed in Alberta from 1973 to 1990 (inclusive). The tumors in women with breast implants were smaller (65.9 percent < or = 2 cm) as compared with the tumors in women without implants (34.1 percent < or = 2 cm), but lymph node and distant metastases were equally frequent in the two groups. The distribution of tumor histologic types did not differ significantly between women with or without implants. Women who had an implant were younger at diagnosis of breast cancer compared with women with breast cancer and no breast implants. The relative 5- and 10-year survival rates did not differ significantly between the two groups, and the Kaplan-Meier survival estimate also was similar. It is concluded that women with breast implants in whom breast cancer develops are not diagnosed in a later stage and do not experience an impaired survival as compared with breast cancer patients without implants.

"Staying power"--absorbable vs. nonabsorbable.

An experiment was designed to compare the "holding power" or "staying power" of absorbable (polyglycolic acid and polyglactin 910) and nonabsorbable (nylon) suture. The aim of this experiment was to determine what provides the lasting strength of the bond between soft tissues that are approximated or plicated. When correcting the rectus diastasis during abdominoplasty, we used nylon sutures in 15 patients and absorbable synthetic sutures in 15 other patients. We then marked the closed folds of the rectus sheath with small metal vascular clips. Two days later and approximately 6 months after operation an upright anteroposterior abdominal x-ray was taken and the position of the metal clips was compared in the test groups. Although there was usually slight separation of the clips after 6 months, no significant difference between the two groups was noted, thereby indicating that holding power is not related to type of suture material but more likely to fibroplasia.

Harmful effects of near-ultraviolet radiation used for polymerization of a sealant and a composite resin.

An electronic device used to polymerize a sealant and a composite resin has been found to emit 365-nanometer radiation at levels sufficient to kill the bacterium Escherichia coli rapidly (greater than 14,000 ergs per square millimeter per second). Because of the absence of shielding on the probe, significant amounts of energy (up to 45% of that at the probe tip) were measured at the sides of the probe. These findings--supported by the well-documented findings of biological damage caused by near-ultraviolet radiation, including skin cancer, damage to the lens of the eye, and mutagenic effects--suggest that clinicians take appropriate precautions to avoid potential hazards to themselves and their patients.

Interaction of concanavalin A with the cell wall of Bacillus subtilis.

Interactions between concanavalin A and cell wall digests of Bacillus subtilis 168 resulted in insoluble complexes as observed by double gel diffusion, turbidity, and analysis of the precipitate. The macromolecular constituent of the cell walls complexing with concanavalin A was the polyglucosylglycerol phosphate teichoic acid. The complex exhibited two pH optima: 3.1 and 7.4. The complex could be dissociated by saccharides which bind to concanavalin A. In contrast to concanavalin A-neutral polysaccharide complexes, formation of the concanavalin A-wall complex was inhibited by salts. It was subsequently shown that salts induce conformational changes in cell wall digests. The data suggested that for complex formation to occur a rigid rod conformation in the glucosylated teichoic acid is probably necessary. Concanavalin A can be used as a probe to study structural features of bacterial cell walls.

Cervical spine injury in patients with facial skeletal trauma.

The records of 2,555 patients admitted to hospital with facial fractures were reviewed for concomitant neck injury. Cervical spine injury occurred in 1.3% of all patients with facial fractures, the incidence rising to 5.5% with facial fractures resulting only from MVA's. Neck injuries occurred most frequently in the setting of MVA's (85%) and multisystem trauma (70%) and tended to involve two main levels of the cervical spine: C2 (31%) and the two lower cervical vertebrae C6 and C7 (50%). Examination of the pattern of cervical spine injury with respect to the pattern of facial skeletal injury does not support the premise of a direct causal relation between them.

Langmuir and scatchard parameters do not describe the binding of Actinomyces viscosus to saliva-treated hydroxyapatite.

The binding of Actinomyces viscosus T14V to saliva-treated spheroidal hydroxyapatite (SHA) beads was studied. The association constant (K) and the total number of binding sites (N) obtained from the Langmuir plots were in good agreement with those reported by other workers (approx. 3 X 10(-8) and 3 X 10(8), respectively). The values for N obtained from Scatchard plots differed from those obtained from Langmuir plots by factors of 10(6) or more. These results suggest that either these equations are inappropriate to describe binding or certain assumptions regarding this system are not being met. The use of these models requires, among other constraints, that the process be reversible and that measurements be taken at equilibrium. A method was developed which allowed a close examination of the equilibrium dynamics without perturbation of the system. The results suggest that the adsorption process is only poorly reversible. Adsorption to SHA was not at equilibrium after 1.5 h. Even when bacteria were allowed to adsorb for longer periods, and the system appeared to approach equilibrium, the increased time of adherence did not significantly alter the derived K or N values. Our results suggest that the use of Scatchard and Langmuir plots is inappropriate to describe binding of A. viscosus to SHA.

Organization of teichoic acid in the cell wall of Bacillus subtilis.

The phytohemagglutinin, concanavalin A (Con A), interacts specifically and reversibly with the polyglucosyl glycerol phosphate teichoic acid of Bacillus subtilis 168 cell walls. Advantage has been taken of this interaction to examine the organization of the surface teichoic acid at the ultrastructural level. Con A-treated whole cells and cell walls contain an irregular, fluffy layer 25 to 60 nm thick which is absent in untreated or alpha-methyl glucoside-treated preparations. This discontinuous layer is present only on the outer profile of Con-A-treated cell walls. The surface teichoic acid is proposed to be oriented perpendicular to the long axis of the cell. Fixation and embedment for electron microscopy result in condensation of this layer which then contributes to the stainable portion of the wall. Con A treatment binds adjacent teichoic acid molecules in their native configuration producing the irregular, fluffy layer visualized.

Electron microscopy of antibody-labelled cells of Streptococcus mutans.

Examination of immune complexes between cells of Streptococcus mutans and homologous antiserum by the techniques of thin-sectioning and freeze-etching revealed that the cells were embedded within and extensive matrix 80-90 nm thick with defined boundaries.

Detection of toluenediamines in the urine of a patient with polyurethane-covered breast implants.

Breast prostheses are implanted for augmentation or during reconstructive surgery. One of the more commonly used prostheses is the polyurethane-sponge-covered silicone gel implant. Some clinicians are concerned about the safety of this product because the polyurethane foam disintegrates in vivo, and its subsequent fate is not known. Polyurethane is a polymer formed by reacting diisocyanates and polyols. This study indicates that the polymer sponge breaks down into its reactive monomers, 2,4- and 2,6-toluenediisocyanate, which are converted into their corresponding diamines. We present evidence of the excretion of the diamine metabolites in the urine of a patient implanted with polyurethane-covered prostheses.

Urinary excretion of free toluenediamines in a patient with polyurethane-covered breast implants.

We report the detection of free 2,4-toluenediamine in urine of a patient implanted with polyurethane-covered breast implants. Samples were collected on several dates, ranging from 21 days to seven months after the insertion of the implants, and these samples all showed the presence of free 2,4-toluenediamine at a concentration of about 1 micrograms/L. The chemical was not found in a urine sample collected before implantation. This finding is important for risk assessment of cancer in patients with this type of breast implant because the chemical is a suspected carcinogen. Free 2,6-toluenediamine, an isomer, was also found in all samples from this patient.

Modification of surface composition of Actinomyces viscosus T14V and T14AV.

The morphology and serology of Actinomyces viscosus T14V and T14AV were compared. When grown in supplemented tryptic soy broth, the virulent strain (T14V) possessed an extensive network of cell surface fibrils. In this medium, the avirulent strain (T14AV) possessed a microcapsule, absent on strain T14V, and a comparatively small number of surface fibrils. Mild acid extraction (Lancefield procedure) solubilized common antigenic components on both strains as well as components detectable only in the virulent strain T14V (virulence-associated antigens 1 and 2). When grown in Socransky chemically defined medium or Carlsson complex medium, the avirulent strain possessed increased amounts of surface fibrils and virulence-associated antigens. Whole cells and extracts of avirulent cells grown in Socransky medium absorbed antibodies to virulence-associated antigens with approximately the same efficiency as did whole cells and extracts of strain T14V, suggesting antigenic similarity between the two cell types. The results strongly support the hypothesis that observable differences between A. viscosus strains T14V and T14AV represent quantitative, rather than qualitative, differences in particular cell surface components. In addition, the magnitude of these differences can be modified by changing growth conditions.