Immunodominant antigens of Porphyromonas gingivalis in patients with rapidly progressive periodontitis

W studied 4 isolates of Porphyromonas gingivalis, ATCC 33277, 381, A7A1-28, and W50, to identify major cell surface antigens and select the best strain from which to obtain antigen for a test vaccine. Immunoglobulin G (IgG) titers measured by enzyme-linked immunosorbent assay using whole-cell sonicates as antigen were significantly elevated for the sera of 64 rapidly progressive periodontitis patients relative to sera of 30 normal control subjects for each of the 4 strains studied. Western blots were prepared for all 4 strains and developed using sera from 22 patients and 20 control subjects to identify and determine the frequency of antibody-binding components. The intensity of binding by patient sera was greatest for the 75-kDa and 55-kDa components. The 43-kDa component was also widely recognized. Strains ATCC 33277 and 381 appeared to be antigenically similar. Because of the higher serum antibody titers, the larger proportion of seropositive patients and higher frequency of binding to specific protein components in Western blots, our efforts were focussed on strain ATCC 33277. Whole-cell sonicates, proteinase K-digested sonicate, lipopolysaccharide, capsular polysaccharide, and whole-cell protein fractions were prepared and evaluated for antigenic activity. By dot immunoblot, most of the antibody binding activity was found in the whole-cell protein fraction, with much lesser amounts in lipopolysaccharide and none in capsular polysaccharide. The antibody-binding activity was accessible on the cell surface, since 98.9% of P. gingivalis-specific antibody, including antibody binding to the 43-kDa, 55-kDa components on Western blot, was removed by whole-cell adsorption. Furthermore, the 43-kDa and 55-kDa but not the 75-kDa component on intact cells were accessible for labeling with 125I, confirming their cell surface location and accessibility.

Response of guinea pigs to a vaccine containing a new adjuvant (SAF) and gram-negative bacteria

Porphyromonas gingivalis is a gram-negative pathogen associated with severe periodontitis in man and other animals. A vaccine against P. gingivalis infection may improve resistance to such infection and disease progression in susceptible individuals. A vaccine composed of formalin-killed P. gingivalis and Syntex adjuvant formulation or saline was tested in guinea pigs. Blood was drawn before and at 2, 4, 6, 8, 24, and 27 weeks after immunization. There was no morbidity or mortality as a result of vaccination, and necropsy revealed no organ abnormalities or residual injection site granulomas. Serum immunoglobulin G (IgG) antibody titer and avidity were measured by enzyme-linked immunosorbent assay, and Western blots were done to determine the immunodominant antigens. The IgG titer increased more rapidly and reached higher values in the animals receiving SAF plus P. gingivalis vaccine than in those receiving saline plus P. gingivalis. Antibody titer decreased by 27 weeks, but avidity was twofold greater at 27 than at 8 weeks. Western blots indicated that protein and carbohydrate antigens are recognized.

Characteristics of HIV-positive chronically mentally ill inpatients

The growing population of chronically mentally ill persons who are HIV-positive or who have AIDS has not yet been adequately studied. We describe the entire population of known HIV-positive inpatients in a state psychiatric center in New York City. In this sample, the typical patient with known HIV infection is as likely to be a man as a woman and is a member of an ethnic minority group. HIV-positive patients had multiple risks for HIV infection including injecting drug use (IDU), sex with IDU partners, prostitution and male homosexual activity. Most patients were at a late stage of HIV-infection, typically with CD4+ cell counts of 400. Discharge plans were complicated by HIV illness and most HIV-positive patients had a longer length of hospital stay than non HIV-positive patients. We discuss the need to plan for the management of increasing numbers of HIV-positive patients in inpatient, outpatient, and residential facilities.

Immunization against Porphyromonas gingivalis inhibits progression of experimental periodontitis in nonhuman primates

Periodontitis is a common infectious disease in which the attachment tissues of the teeth and their alveolar bone housing are destroyed, resulting in tooth loss. The gram-negative anaerobic microorganism Porphyromonas gingivalis has been closely linked to severe forms of the disease. We show for the first time that immunization of the primate Macaca fascicularis with killed P. gingivalis in Syntex Adjuvant Formulation-M inhibits progression of periodontal tissue destruction.

Significance of antibodies against human sperm FA-1 antigen in immunoinfertility

A fertilization antigen (FA-1) has been identified on human sperm cells that is involved in human fertilization. To better explain the participation of FA-1 in human infertility, the relationship of anti-FA-1 antibodies with the presence of general antisperm antibodies and with sperm function was examined in the sera of 30 men and women. None of the sera from fertile men and women (n = 10) reacted with FA-1. In contrast, 55% of the immunoinfertile sera (n = 20) that were positive for antisperm antibodies detected by OPTI-BEAD (immune-labeled microsphere) tested positive with FA-1 (p < .05). In these sera, penetration of hamster oocytes was reduced and was inversely related to monospecific anti-FA-1 absorbance values determined by an ELISA and with heterospecific general antisperm antibody binding to sperm in the OPTI-BEAD test (p < .05). Anti-FA-1 activity approached significance with antisperm antibody binding to the sperm head (p = .052). It is concluded that immunoinfertile sera have antibodies reacting with the FA-1 sperm antigen and their presence is significantly related to results of other functional tests, such as the SPA and the OPTI-BEAD test. The association of anti-FA-1 antibodies with antibody binding site (sperm head) may be relevant to the diagnosis and treatment of immunoinfertility.

Effect of treatment on titer, function, and antigen recognition of serum antibodies to Actinobacillus actinomycetemcomitans in patients with rapidly progressive periodontitis

Although periodontal treatment by scaling and root planing (SCRP) is known to induce bacteremia, the effect of this procedure on the host immune response is not known. We have determined pre- and post-SCRP immunoglobulin G antibody titers to antigens of Actinobacillus actinomycetemcomitans in the sera of 22 patients with rapidly progressive periodontitis. We also assessed the ability of these sera to enhance phagocytosis and killing of A. actinomycetemcomitans by human polymorphonuclear leukocytes by using a polymorphonuclear leukocyte chemiluminescence (CL) assay. Specific anti-A. actinomycetemcomitans antibody titers were significantly increased at 6 and 12 months after beginning treatment, and CL values were significantly increased at 12 months, whereas mean interproximal pocket depths were significantly decreased at 12 months after beginning treatment. When patients were classified as either seropositive (twice the median titer of control subjects; n = 10) or seronegative (n = 12), both median titers and CL values were significantly increased for the seronegative group at 6 and 12 months after treatment. In the seropositive group, only the median titer was significantly increased at 12 months. Western blot (immunoblot) patterns for six seronegative and six seropositive patients differed remarkably at the baseline. Before treatment, all of the seropositive patients recognized high-molecular-mass lipopolysaccharide (LPS) and a large number of protein components. Patterns were virtually unaffected by therapy. Before treatment, only one of the seronegative patients recognized the LPS smear and none reacted strongly with protein components. Following treatment, slight LPS staining was observed for five of six seronegative patients and detection of protein bands was enhanced in all cases. We conclude that treatment by SCRP induces a humoral immune response, especially in seronegative patients, and that response may play a role in the observed beneficial effects of periodontal treatment.

Serum antibody opsonic activity against Actinobacillus actinomycetemcomitans in human periodontal diseases

Actinobacillus actinomycetemcomitans is frequently associated with severe periodontitis. Many periodontitis patients have elevated levels of serum IgG antibodies to A. actinomycetemcomitans, but the role of these antibodies is unknown. This study evaluated the functional capacity of anti-A. actinomycetemcomitans IgG antibody to enhance phagocytosis of A. actinomycetemcomitans by polymorphonuclear leukocytes. Chemoluminescence assays were done using sera from 64 subjects, 61 of whom had severe periodontitis; results were compared with the subject's anti-A. actinomycetemcomitans IgG titer and avidity. There was a strong correlation between chemoluminescence and antibody log titer (P < .00001) and a weak correlation between chemoluminescence and antibody avidity (P < .05). The results support the hypothesis that anti-A. actinomycetemcomitans IgG antibodies are important in promoting phagocytosis and killing of A. actinomycetemcomitans. Subjects who develop high levels of highly avid antibodies against A. actinomycetemcomitans may have greater resistance to continued or repeated infection by this pathogen.

Fimbria damage and removal of adherent bacteria after exposure to acoustic energy

The physical effects of low-frequency acoustic energy on Actinomyces viscosus were studied with electron microscopy to explore both acoustically induced damage to fimbriae on the surface of these bacteria and acoustic removal of bacteria from saliva-treated hydroxyapatite disks. A bacterial suspension was exposed to acoustic energy from a laboratory acoustic generator (50 kPa, 200 Hz) and from a new electronic toothbrush, the Sonicare. The exposed bacteria were examined with electron microscopy after negative staining. A decrease in both the percentage of bacterial surface covered with fimbriae and the fimbria length was observed after acoustic exposure. To study the acoustic effects on adherent bacteria, A. viscosus bound to hydroxyapatite disks were exposed to acoustic energy and examined with scanning electron microscopy. Quantitative evaluation of the micrographs for the number of bacteria present after exposure revealed that acoustic energy removed both bacteria adherent to the hydroxyapatite surface and adherent to each other. The results support the concept that an electronic toothbrush employing low-frequency acoustic energy may help prevent and control periodontal diseases by altering bacterial adherence.

Safety testing of a new electronic toothbrush

While there have been major advances in understanding the causes and treatments of the inflammatory periodontal diseases in the past decade, there is still high reliance on the patient to prevent progression of disease through daily oral hygiene, primarily toothbrushing and flossing. A new electronic toothbrush, which produces mild fluid cavitation as well as rapid fluid streaming, has been developed and has shown promise in the ease and efficacy with which it removes plaque. In order to determine the safety of frequent and prolonged use of this device, the gingival tissues of 6 mongrel dogs were exposed to excessively long daily exposures to this toothbrush for up to 2 months. Each quadrant of each dog's mouth was randomly assigned a different treatment: no brushing, manual brush 1.0 minute, electronic brush 1.0 minute, or electronic brush 7.5 minutes. The dogs were examined weekly by a periodontist who was blinded to the treatments. Plaque scores and bleeding on probing scores were calculated, and possible gingival irritation was monitored carefully. At the end of the trial gingival biopsies taken from all the test areas. These were processed for conventional histopathologic evaluation and examined by an oral pathologist who was also blinded as to the treatments. The results showed that brushing a single posterior segment of teeth for 7.5 minutes daily for 2 months with the electronic brush did not result in any clinically or histologically evident damage to the gingiva. Rather, the areas so treated showed excellent health as determined by both clinical and histologic criteria.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased proliferative capacity of CD4+ and CD8+ T lymphocytes from mutant sphha/sphha mice is associated with increased IL-2 receptor expression

We previously discovered that mutant anemic mice (sphha/sphha) show increased numbers of cycling lymph node T lymphocytes when analyzed by pulse and continuous infusion of tritiated thymidine. We have now further analyzed this in vivo phenomenon by evaluating the in vitro proliferative response of anti-CD3 activated lymphocytes from anemic mice using flow cytometric cell cycle analysis with 5'-bromodeoxyuridine and Hoechst dye. We determined that sorted CD4+ and CD8+ T lymphocytes from anemic mice have significantly greater proliferative capacity when compared with syngeneic control (+/+) mice (P < 0.001). In order to explain this increased growth capacity, we examined whether these cells exhibit differences in cell-surface phenotype (Pgp-1 and IL-2 receptor expression), activation state, or transmembrane signaling, or alterations in accessory cells or cytokines. Increased proliferation of T cells from anemic mice was associated with a larger percentage of T cells expressing IL-2R (p55 or CD25) at 24 and 48 hr after activation. Increased proliferative capacity was not associated with differences in activation state, Pgp-1 phenotype, transmembrane signaling, accessory cells, or cytokines. The mechanism for the abnormally high proliferative rate of T cells from anemic mice remains unclear, but we suggest that this mutant mouse may provide an important model for further studies on the molecular basis of T-cell replication.

Opsonic antibody activity against Actinobacillus actinomycetemcomitans in patients with rapidly progressive periodontitis

Actinobacillus actinomycetemcomitans has been closely associated with early-onset, severe periodontitis, and such patients often have serum immunoglobulin G (IgG) antibodies reactive with antigens of this gram-negative pathogen. We examined the functionality and potential importance of these antibodies. The opsonic activity against A. actinomycetemcomitans of sera from 30 patients with rapidly progressive periodontitis (RPP) and from 28 periodontally normal subjects was tested by using polymorphonuclear leukocyte (PMN) chemiluminescence and bactericidal assays. Peak chemiluminescence values correlated strongly with killing observed in the PMN-dependent bactericidal assay (r = 0.88; P < 0.001). Neither the mean IgG titer nor the mean peak chemiluminescence differed significantly between the two groups. However, when the relationship between chemiluminescence and titer was examined, regression analysis showed that antibodies present in low-titer normal sera were significantly more effective at opsonizing A. actinomycetemcomitans than antibodies present in low-titer RPP patient sera (P = 0.04). Thus, periodontally normal individuals may be better able than RPP patients to clear A. actinomycetemcomitans in early stages of colonization, and anti-A. actinomycetemcomitans antibodies in RPP patients may be relatively ineffective in preventing infection by this organism.

[AIDS counseling in social welfare for prostitutes in the rural area]

Prostitute welfare and AIDS counselling are in the hands of one person in the rural area of the Westerland district. This offers the opportunity of continuously preventing this disease and giving guidance and the "human touch" in close care in case of a possible infection, especially in view of the lower number of cases examined and advised compared with the figures in the big cities. An anonymous poll among 41 prostitutes shows that they approve of and are satisfied with the concept of the "G-welfare". It also shows that the prostitutes themselves are hardly aware of the HIV-risk, that their customers only rarely accept condoms and that there are problems in the use and the toleration of condoms. These difficulties are the main aspects of the preventive work, as well as the psycho-social care and the personal relationship to those examining.

Serum immunoglobulin G antibody to Porphyromonas gingivalis in rapidly progressive periodontitis: titer, avidity, and subclass distribution

Porphyromonas gingivalis is a suspected pathogen in rapidly progressive periodontitis (RPP). We have determined the anti-P. gingivalis serum immunoglobulin G (IgG) isotype response and avidity and the subclass titer distributions for 30 RPP patients and 30 age-, sex-, and race-matched healthy subjects by using enzyme-linked immunosorbent assay technology. Patients and control subjects were classified as seropositive if their total IgG response to P. gingivalis was twofold or more than the median response in healthy subjects. The predominant antibody responses for both patients and healthy subjects were IgG2 and IgG3, with a subclass order of IgG2 greater than IgG3 greater than IgG1 greater than IgG4. The avidity of the IgG response was highest for the seropositive healthy subjects and was no different between seronegative and seropositive RPP patients. The subclass antibody responses did not depend on gender, and there were no correlations between titer, avidity, or subclass with disease severity in the RPP patients as measured by pocket depth or bone loss on dental X rays. The seronegative RPP patients exhibited antibody responses that were greater than the responses of seronegative healthy subjects for all four subclasses, while the seropositive RPP patients had higher IgG1 and IgG4 levels than seropositive healthy subjects. These findings are consistent with the hypothesis that both carbohydrate and protein antigens are important in the IgG response to P. gingivalis. The relative predominance of IgG2, a subclass which lacks strong complement fixation and opsonic properties, and the low avidity of patient anti-P. gingivalis IgG antibodies suggest that humoral responsiveness to infection with P. gingivalis may be ineffective in clearing this organism.

Reduction in adherence of Actinomyces viscosus after exposure to low-frequency acoustic energy

The ability of low-frequency (200 Hz) acoustic energy to reduce the adherence of Actinomyces viscosus T14V to saliva-treated hydroxyapatite (SHA) disks was studied. An acoustic pressure range between 0 and 65 kPa and exposure durations between 0 and 8 min were used to study the levels necessary to significantly alter adherence. The effects of acoustic exposure on both bacteria in liquid and bacteria already adhering to SHA disks were studied. A modified enzyme-linked immunosorbent assay was used to assess bacterial adherence. For bacterial suspensions exposed prior to addition to SHA disks, it was found that reductions in adherence were greater for lower bacterial concentrations. Exposure of bacteria already adhering to SHA disks resulted in a decrease in adherence that was independent of the bacterial concentration and linearly related to the logarithm of the exposure duration. In addition to affecting adherence, acoustic energy also dispersed bacterial aggregates. Our results support the concept that low-frequency sonic energy applied orally may be of therapeutic value in reducing adherence and colonization of teeth by plaque bacteria.

Activated lymphocyte subsets in adult periodontitis*

The activation state of T and B lymphocytes in the peripheral blood of periodontitis patients may be a reflection of disease activity. We have utilized 2- and 3-color flow cytometric analyses using a new chromophore, peridinin chlorophyll A protein, and conventional dyes, fluorescein isothiocyanate and phycoerythrin, conjugated to monoclonal antibodies against activated lymphocyte surface markers to measure blood lymphocyte subsets from 18 periodontitis patients and 16 periodontally healthy control subjects. Two-color flow cytometric analysis demonstrated that the frequency of CD4+ and CD5+ T cells, CD20+ B cells, and CD16+ NK (natural killer) cells were increased in periodontitis patients. Of particular interest, CD4+ activated "memory" T cells, CD5+ B cells, and CD56+ NK effector cells were increased significantly in periodontitis patients (p less than 0.05). While the relationship of lymphocyte activation to periodontal disease activity remains unclear, there may be potential for using 2- and 3-color flow cytometry to subcategorize periodontitis patients into high- and moderate-risk groups.

Altered lymphocyte populations in sphha/sphha mice with chronic hemolytic anemia

Lymphocyte kinetics and phenotype were examined in mutant anemic sphha/sphha mice that manifest a lifelong lymphocytosis which accompanies their chronic hemolytic anemia. Anemic mice have significant increases in CD4+, CD8+, and sIgM+ lymphocytes in peripheral blood. Pulse and continuous infusion studies with [3H]TdR suggest that this apparent lymphoid expansion is not due to increased production of lymphocytes in bone marrow or thymus but rather to a redistribution of lymphocytes from the spleen to other peripheral lymphoid tissue sites as well as increased proliferation of T and B lymphocytes in lymph nodes. This murine model could be useful to examine lymphocyte perturbations that may accompany chronic hemolytic anemia in humans.

Humoral immune responses to Porphyromonas gingivalis before and following therapy in rapidly progressive periodontitis patients

We have performed studies aimed at elucidating the nature of the humoral immune response in rapidly progressive periodontitis (RPP). We analyzed the sera of 36 periodontally normal subjects and 36 RPP patients for titers and avidities of IgG antibodies reactive with the antigens of Porphyromonas gingivalis using ELISA, prior to and following treatment. We used whole-cell sonicate, purified lipopolysaccharide (LPS), and total extractable protein as plate antigens. Twelve of the patients had antibody titers at least 2-fold greater than the median of the controls and were designated as seropositive. The remaining 24 patients had titers that did not exceed twice the median titer of the controls and were designated as seronegative. For both patient groups, antibody titers were highest when whole-cell antigen was used, intermediate for LPS, and lowest for the protein fraction. Following treatment, median titer for seropositive patients decreased from pretreatment values of 241.7 to 76.5, while median titer for seronegative patients increased from 39.5 to 80.1. Avidities of pretreatment sera from both patient groups for all 3 antigen preparations were lower than the median avidities of the control sera. Avidity significantly increased following treatment to levels greater than those for control sera in both patient groups. Thus, some young adults with severe periodontitis mount a humoral immune response and produce high levels of serum IgG antibodies reactive with antigens of P. gingivalis, while others do not. The antibodies produced are of relatively low avidity, and may therefore be relatively ineffective biologically. Therapy, which greatly reduces antigen load, appears to stimulate production of higher avidity IgG antibodies in both patient groups; in the seropositive group, low avidity antibodies appear to be replaced by antibodies of higher avidity. Both the purified LPS and protein fractions contain reactive antigen(s), although LPS binds more antibody. Our data are consistent with the idea that many RPP patients do not produce protective levels of biologically functional antibody during the course of their natural infection, but they may be stimulated to do so by treatment.

Transplantation studies in mice with congenital hemolytic anemia

Sphha/sphha anemic mice have an abnormality in the erythroid membrane protein, alpha spectrin, and exhibit multiple related clinical abnormalities, including spherocytosis, shortened red cell survival, chronic hemolysis, hemosiderosis, and extramedullary hematopoiesis. In addition, these mutant mice exhibit a granulocytosis and lymphocytosis, lymph node hyperplasia, elevated serum immunoglobulins, membranoproliferative glomerulonephritis, and decreased lifespan--abnormalities that are less clearly attributable to a spectrin defect. In order to further elucidate the mechanisms of disease in these animals, we undertook a series of bone marrow transplantation experiments. Transplantation of anemic marrow into lethally irradiated congenic +/+ mice resulted in chronic spherocytosis, hemolytic anemia, peripheral leukocytosis, and extramedullary hematopoiesis. Additionally, transplant recipients of anemic marrow which had received a higher radiation dose (12 Gy) had increased numbers of peripheral blood CD4+ and CD8+ lymphocytes, a hypocellcular thymus, and a severe pneumonitis characterized by nodular areas of consolidation and edema. Mice receiving congenic +/+ marrow and irradiated with the same radiation dose exhibited minimal pulmonary abnormalities. Anemic mice transplanted with congenic +/+ marrow usually died, but the survivors exhibited reversal of some clinicopathological changes. These results would suggest that the clinical abnormalities of sphha/sphha mice are in part attributable to abnormalities of hematopoietic stem cells but may also involve defects in other cell types. The pathogenesis of the accompanying lymphoid abnormalities observed in this mutant anemic mouse and any correlation with the erythroid spectrin defect are presently unknown. The pulmonary disease that develops in the transplant recipients of anemic marrow needs to be characterized further but may represent a unique model of lung injury.

Polyclonal B-cell activation in periodontitis

The evidence that periodontitis-associated bacteria contain potent PBA factors is very strong. Clearly, antibodies directed against non-oral antigens are produced in the inflamed periodontal lesion, and PBA appears to contribute to that production. It is also clear that B cells and plasma cells are the major cell types in the periodontal lesion. Furthermore, alterations in the regulation of B-cell responses to PBA factors are associated with severe periodontal disease. However, evidence demonstrating that activated B cells and plasma cells are directly involved in the pathogenic mechanisms leading to destruction of the periodontal support is still circumstantial. Polyclonal B-cell activation and potential pathways by which PBA-stimulated cells could be involved in periodontal destruction remain largely hypothetical. It appears that IL-1 is an important osteoclast-activating agent, and that LPS, which is a potent PBA factor in many systems, can elicit IL-1 production by B cells as well as by the monocyte/macrophage lineage. Recent data indicating that IL-1 is produced by numerous malignant B-cell lines lend support for the idea that B-cell IL-1 could be important in bone resorption. It is also likely that polyclonal activation may lead to production of autoantibody such as anti-type I and anti-type III collagens, and the destruction of self tissues through ADCC reactions, immune complex formation, and complement activation. Further research is needed to determine how the B cell/plasma cell may participate in tissue injury in periodontitis, and how the B-cell response to PBA factors is regulated.

Oral mucosal lesions: association with the presence of antibodies to the human immunodeficiency virus

To assess the relationship between oral lesions and antibodies to the human immunodeficiency virus, oral examinations of 803 homosexual males were conducted at the time of serologic testing. Nineteen percent were HIV seropositive. Thirty percent of antibody-positive subjects had one or more oral lesion(s), as compared with 7% of antibody-negative subjects (p less than 0.001). The presence of oral lesions was significantly associated with HIV seropositivity: a subject was 5.7 times as likely to have serum antibodies if he had one or more oral lesions (95% confidence interval, 3.5 to 9.1; p less than 0.001). This significant association with HIV seropositivity was only partially explained by cigarette smoking (adjusted odds ratio 3.1; 1.4-6.8; less than 0.006). Specific conditions that were significantly associated with seropositivity included candidiasis, hairy leukoplakia, periodontal disease, and Kaposi's sarcoma. Other diseases identified included acute necrotizing ulcerative gingivitis, mucocutaneous ulcerations, and oral warts. Oral findings may occur earlier in the natural history of infection than previously reported.

Clinicopathologic features of young and old sphha/sphha mice. Mutants with congenital hemolytic anemia

A colony of mice with congenital hemolytic anemia, sphha/sphha, were evaluated over a 3-year period. Prominent findings included decreased survivability, reticulocytosis, increased peripheral blood leukocytes, extramedullary hematopoiesis in liver and spleen, lymphoid hyperplasia and membranoproliferative glomerulonephritis. Older (12 to 21 months) anemic animals had elevated serum levels of IgG1 and IgA. There was deposition of C3, IgG, IgM, and IgA in renal glomeruli of both control and anemic mice, but deposition of IgM and IgA was more prominent and widely distributed in anemic animals and correlated with mesangial expansion and the presence of electron dense deposits in the mesangium and in glomerular capillary walls. Prominent renal tubular hemosiderosis was noted in young and old anemic mice. The relation between the hemolytic anemia and glomerular disease is unclear but these mice may be an animal model useful for exploration of changes attendant with chronic hemolysis and evaluation of renal disease that accompanies hemolytic anemia.

Epidemiology of acute necrotizing ulcerative gingivitis

In the last 60 years, there have been approximately 50 studies of various suspected risk factors associated with acute necrotizing ulcerative gingivitis. Two thirds of these studies have been either surveys or case reports; nearly all the rest have been case-control studies. There have been only a few longitudinal and population-based studies, most of which were in high-risk populations. The findings of many studies pertain to gingivitis in general rather than in acute necrotizing ulcerative gingivitis in particular; the findings of other studies are based on small numbers or solely on case histories without the inclusion of control subjects. There are comparisons between the epidemiology of acute necrotizing ulcerative gingivitis as it occurs in military populations and the epidemiology of meningococcal meningitis (98-103). Both diseases have been reported in closed communities such as in young recruits away from home and in new surroundings. A temporal trend upward in disease frequency was described for both infections during World War II. Both infections appear to be characterized by low communicability, with no documented transmission by fomites or vectors. Furthermore, active disease in both cases is associated with markedly increased numbers of normally indigenous flora: B. intermedius in the case of acute necrotizing ulcerative gingivitis and Neisseria meningococcus in the case of epidemic meningococcal meningitis. Risk factors associated with both diseases include crowding, physical fatigue, increased stress, low socioeconomic status, and failure of host defense mechanisms. In general, there is potential for longitudinal studies of young people such as new military recruits and college students who are undergoing the transition from dependence to independence. It is intriguing that these young adults are suddenly at increased risk of this disease in late adolescence when they should be at peak fitness and, just as suddenly, at decreased risk after their early thirties. It appears that the dynamic tension between bacterial agents, environmental stressors, and host defense mechanisms is abruptly altered in certain young people, allowing the characteristic lesions to develop. Furthermore it appears that, in the United States at least, the disruption is limited primarily to white people relative to black people. It is possible that disease develops because young adults are brought together from diverse locations and perhaps exposed to a new microbial agent. However, acute necrotizing ulcerative gingivitis has not been demonstrated clearly to be transmissible, and if it is, the mode of transmission is not known.(ABSTRACT TRUNCATED AT 400 WORDS)

Deionization of formamide with Biorad AG501-X(D)

We have studied different conditions of the deionization of formamide with Biorad mixed bed resin AG501-X(D) and find that contrary to the popular usage, drying the resin before deionization produces the best results. In a typical deionization procedure, conductivity initially goes down, reaches a minimum plateau and finally goes up again. The initial rate of deionization, the minimum conductivity reached at the plateau and the rate of final rise in conductivity depend on whether the resin is dry or wet (i.e., straight from the bottle) and on the amount of resin used. In general, wet resin produced faster initial deionization, higher minimum conductivity and quicker final rise in conductivity. Surprisingly, a smaller amount (5%) of resin worked better than a larger amount (20%). With smaller amount of resin, although initial deionization was slower, the minimum conductivity achieved was lower and the final rise in conductivity was slower. This was partly due to the fact that the conductivity of formamide increases faster with increasing amount of water in it.