Increased expression of human thioredoxin/adult T cell leukemia-derived factor in Sjögren's syndrome

OBJECTIVE

To determine the involvement of human thioredoxin/adult T cell leukemia-derived factor TRX/ADF) in Sjögren's syndrome (SS) and the correlation with Epstein-Barr virus (EBV).

METHODS

Indirect immunohistochemical techniques and reverse transcriptase polymerase chain reaction were utilized to analyze TRX/ADF expression and the presence of EBV, using 6 normal tissues and 23 surgical specimens. The kinetics of expression of TRX/ADF induced by EBV was examined in vitro with peripheral blood B cells from EBV-seronegative donors.

RESULTS

Marked expression of TRX/ADF was found in the infiltrating B cells and the epithelial cells of salivary gland tissues from patients with SS (11 of 12 cases), but not in those from patients with other salivary gland inflammatory conditions (0 of 11 cases) or those of normal individuals (0 of 6 cases). In immunohistologic analyses, a striking topographic correlation between TRX/ADF and EBV was found. The coexistence of TRX/ADF messenger RNA and EBV DNA was detected by polymerase chain reaction (r = 0.75, P < 0.01). Peripheral blood B cells from EBV-seronegative donors showed de novo synthesis of TRX/ADF following in vitro infection with EBV. EBV-infected B cell lines all expressed TRX/ADF. TRX/ADF was not detected in non-EBV-infected cells. Tumors in SCID mice reconstituted with mononuclear cells of salivary glands from SS patients, which were composed of human B cells carrying EBV DNA, were positive for TRX/ADF.

CONCLUSION

These findings suggest that TRX/ADF expression closely reflects the intracellular event of EBV reactivation in SS. This is also the first report to show the ectopic in vivo expression of TRX/ADF in human autoimmune disease.

Borrelia burgdorferi OspA is an arthropod-specific transmission-blocking Lyme disease vaccine

Borrelia burgdorferi, the spirochetal agent of Lyme disease, is transmitted by Ixodes ticks. A vaccine based on B. burgdorferi outer surface protein (Osp) A protects mice from spirochete infection. Here we report on the expression of OspA on spirochetes inside engorging ticks and relate OspA expression to antispirochetal immunity. Spirochetes in the gut of unfed nymphal ticks were stained by an OspA antibody, whereas in feeding ticks, the majority of spirochetes in the gut and salivary glands did not stain with the antibody. Thus, OspA was not expressed on most spirochetes during transmission from the vector to the vertebrate host. To examine the mechanism of protection afforded by OspA antibody, mice were passively immunized with OspA antibody at different times relative to tick attachment. When OspA antibody was administered to mice before or at the time of tick attachment, spirochetal development events in the vector, such as growth and salivary gland invasion, were blocked and the mice were protected from B. burgdorferi infection. When OspA antibody was administered to mice 48 h after tick attachment, spirochetes persisted in the nymphs and the mice were not protected despite the presence of circulating antibodies in the host as well as in the tick blood meal. Thus, OspA immunity appears to be effective only during a narrow window time at the beginning of the blood meal when antibodies bind to OspA-expressing spirochetes in the tick gut and block transmission from the vector to the host.

Mycobacterial disease of the head and neck: current perspective

The worldwide increase in mycobacterial diseases, tuberculous and nontuberculous, and their association with human immunodeficiency virus infection has had and will continue to have an impact on the practice of otolaryngologist-head and neck surgeons. Epidemiologic and ecologic changes in tuberculosis and nontuberculous mycobacterial diseases tend to blur former clinicopathologic distinctions among these groups, especially in immunocompromised hosts. Diagnosis depends on objective identification of the mycobacterium, a process facilitated by molecular diagnostics.

Growth and migration of Borrelia burgdorferi in Ixodes ticks during blood feeding

We have studied the growth of Borrelia burgdorferi in nymphal ticks (Ixodes scapularis) feeding on mice using confocal fluorescence microscopy to follow the distribution of spirochetes. In starved nymphs, the bacteria were only detected in the midgut and each nymph had a mean of 496 spirochetes. Upon attachment of nymphs to the host, the bacteria grew with a doubling time close to 4 hr and reached a mean of 7,848 spirochetes per nymph 15 hr after attachment. During this initial period (36 hr) of rapid growth, the bacteria appeared to be restricted to the gut, but after 48 hr, the spirochetes had disseminated to the salivary glands in the majority of nymphs examined. Thus, a critical event that allows the spirochetes to disseminate and infect the salivary glands takes place 36-48 hr after attachment. A maximum number of 166,575 spirochetes per nymph was noted 72 hr after attachment. Soon after completion of feeding and detachment from the host (96 hr), the mean number of spirochetes decreased to 95,410 per nymph and the spirochetes appeared to be cleared from organs other than the midgut. Thus, dissemination of spirochetes within the vector appears to be a transient phenomenon. These results provide strong evidence in favor of a salivary route of disease transmission while also demonstrating the utility of confocal microscopy to study vector-pathogen interactions in general.

[The frequency of generalized infection in adult fasting ticks of the genus Ixodes in foci of borreliosis in Russia and the USA]

A total of 740 adult Ixodes persulcatus ticks were collected from the vegetation by flagging in Russian foci where Borrelia afzelii and B. garinii circulate, and 156 I. dammini ticks were collected in northwestern USA regions in foci with B. burgdorferi s.str. circulation. Smears prepared from the internal organs of ticks were stained according to Romanovsky-Giemsa and analyzed under a microscope at a x 1125 magnification. All borreliae in 250 microscopic fields were counted, and concentration of microbial bodies per 100 microscopic fields was determined. The general level of infection by Borrelia in both vectors was similar: 26.2 x 3.2 in I. persulcatus and 26.3 +/- 7 in I. dammini. However, the proportions of ticks with generalized infections differ considerably (12.9 +/- 4.8 in I. persulcatus compared with 2.4 +/- 4.8 in I. dammini; significance of difference t = 3.1). We did not reveal any definite increase in the proportion of ticks with borreliae in the salivary glands among ticks with high concentrations of microbial bodies in the gut. In 25 I. persulcatus ticks with generalized infections, series of actual numbers of borreliae (per 100 microscopic fields) found in the gut and salivary glands did not correlate with one another (r = -0.23). These results confirm our previous conclusion (Korenberg, 1994) that frequencies of generalized infection in main vectors of different ixodid tick-borne borrelioses are also different, which is probably due to peculiarities of relationships between spirochetes of each species and corresponding tick vectors. These factors can be responsible for differences in the ways of horizontal and vertical transmission of pathogens belonging to the group under study.

Salivary glands and saliva of Amblyomma variegatum ticks: comparison of immatures and adults in relation to the pathogenesis of dermatophilosis

Salivary glands from immature and adult Amblyomma variegatum were compared for differences in potential components responsible for the systemic aggravation by adult ticks of the skin disease dermatophilosis. Whole salivary glands from adult, nymphal and larval A. variegatum ticks were compared for structural differences by light microscopy and for protein content by gel electrophoresis. Type-2 salivary gland acini from adult ticks at the second stage of feeding contained significantly greater (P < 0.01) proportions of c1 secretory granules than those from either of the immature instars. There was also significantly more area occupied with e secretory granules in the type-3 salivary gland acini from adult ticks compared with larval ticks. Electrophoresis of whole salivary glands showed seven bands present only in the adult material; of these, three were dense bands at 37, 35 and 31 kDA. Electrophoresis of saliva from adult and nymphal A. variegatum obtained by artificial stimulation showed that nine bands were unique to the saliva produced by adults; of these nine bands one was a dense band at 67 kDa. It was concluded that adult salivary material was different from that of immature ticks and that further studies on the relationship between the feeding of adult A. variegatum and dermatophilosis should investigate these components unique to the adults.

[The presence of Borrelia in the intestines and salivary glands of spontaneously infected adult Ixodes persulcatus Schulze ticks during bloodsucking]

A direct microscopic analysis of fixed smears and live preparations was used to reveal whether spirochetes are present in the gut and salivary glands of adult Ixodes persulcatus ticks spontaneously infected with Borrelia garinii and B. afzelii. Unfed ticks collected from a vegetation, partially fed ticks removed from human bodies, and ticks deliberately fed on laboratory animals were studied. In each preparation, all spirochetes were counted in 250 microscopic fields, and their concentration per 100 microscopic fields was determined. A total of 1962 ticks were individually analysed. The methods used on the study allowed a reliable identification of Borrelia in the viscera of not only unfed, but also of partially fed ticks. The infection rate in ticks that started bloodsucking was slightly lower than in the unfed ticks. This was associated with the decreased spirochete concentration in the preparations made from the partially fed ticks. Borrelia were frequently found in the salivary glands of the unfed infected I. persulcatus. During the first two to three days of bloodsucking, neither the proportion of ticks with spirochetes in the salivary glands, nor the spirochete concentrations increase. Borrelia migration from the tick gut into the salivary glands during early bloodsucking is not a prerequisite for or even important for pathogen transmission with saliva. The transmission rate appears to depend on the baseline proportion of the unfed ticks carrying spirochetes in their salivary glands.(ABSTRACT TRUNCATED AT 250 WORDS)

Dispersal of the Lyme disease spirochete Borrelia burgdorferi to salivary glands of feeding nymphal Ixodes scapularis (Acari: Ixodidae)

Salivary gland explant cultures from 3/16 (19%) of unfed nymphal Ixodes scapularis Say contained Lyme disease spirochetes, increasing to a maximum of 14/16 (88%) at 72 h of tick feeding. Homogenates of tick salivary glands did not produce infection in laboratory white mice unless harvested from ticks attached for > or = 60 h. Dispersal of spirochetes to the salivary glands appears to occur during the act of tick feeding, thus affecting the ability of ticks to transmit Borrelia burgdorferi.

Conserved recombinant antigens of Anaplasma marginale and Babesia equi for serologic diagnosis

The competitive inhibition ELISA (CI-ELISA) format overcomes problems associated with antigen purity since the specificity of the CI-ELISA depends solely on the monoclonal antibody (mAb) used. Therefore, the CI-ELISA format is well suited for use with recombinant antigens. Molecular clones expressing a conserved 19 kDa protein of Anaplasma marginale and a 34 kDa protein of Babesia equi were derived and characterized. The 19 kDa A. marginale protein, conserved in all recognized Anaplasma species, and present in the infected tick salivary gland, was reactive with all bovine immune sera tested. The 34 kDa B. equi protein contains a protein epitope bound by antibody in equine immune sera from 19 countries. Monoclonal antibodies reactive with these proteins were derived and applied with recombinant copies of the 19 kDa A. marginale and 34 kDa B. equi proteins in a CI-ELISA format.

Tick salivary gland physiology

The multifunctional, morphologically complex salivary glands are essential to the biological success of ticks and are intricately involved in the transmission of pathogens. They are innervated, and there is convincing evidence that dopamine is a neurotransmitter at the neuroeffector junction controlling fluid secretion. As feeding progresses, the rate of salivary fluid secretion increases greatly, enabling the ixodid tick to concentrate the bloodmeal by returning excess water and ions to the host. Saliva in feeding ticks is rich in bioactive components and exhibits a range of pharmacological properties. Factors identified in saliva or salivary glands include cement to help anchor the mouthparts to the host, various enzymes and inhibitors, histamine agonists and antagonists, prostaglandins, antihemostatic factors, and immuno-modulating factors. A secretion from the salivary glands allows ticks to absorb water from the air during the lengthy periods off their hosts. The physiology of this remarkable organ provides a striking example of strategies that have evolved to meet the challenge of a unique parasitic life style.

Cellular and molecular interrelationships between ticks and prokaryotic tick-borne pathogens

Tick-borne prokaryotic pathogens share a very intimate relationship with the vectors. Ingestion during the bloodmeal places the microbe into the gut lumen whence it must travel to the salivary glands at the right time for transmission during a subsequent feeding. This crucial event requires coordination between pathogen development and arthropod host activities that may be mediated by the expression of genes specific for the vector phase of the pathogen. Invertebrate hormones or factors associated with tick tissues may provide the cues that signal changes in tick physiology that induce necessary steps in the pathogen, such as colonization of ovaries during egg development in preparation for transovarial transmission or dispersion to the salivary glands at the time of a bloodmeal. These hypotheses cannot easily be investigated within the complex environment of the tick, but tick cell culture offers a simplified system with which to examine many of these important interrelationships.

[Laboratory diagnosis of rabies in chiroptera carried out in a metropolitan area of southeastern region Brazil]

Between January, 1988 and December, 1992 the S. Paulo Animal Disease Control Center subjected 289 bats to rabies examinations, utilizing the direct immunofluorescence and biological techniques. Two insectiverous bats belonging to the species Nyctinomops macrotis, representing 0.69% of the total sample, tested positive. Both animals had been captured alive in residential neighborhoods of the city, one in 1988 in the living room of a 7th floor apartment and the other in 1990 on top of a wall surrounding a private house. In the biological tests, the disease showed incubation periods of 13 and 11 days respectively. Although the existence of infected insectiverous bats in urban areas is cause for concern, indiscriminate predatory action against such species can in no way be justified-particularly bearing in mind their importance in preserving the ecological balance of the insect population so prevalent in cities.

Murine cytomegalovirus-associated pneumonitis in the lungs free of the virus

At 4 wk after intraperitoneal inoculation of murine cytomegalovirus (MCMV) in adult BALB/c mice, MCMV remained detectable only in the salivary glands. When T cells of these mice were activated by a single injection of anti-CD3 epsilon monoclonal antibody, mice died of interstitial pneumonitis at 24-48 h after injection, accompanied by elevation of serum levels of TNF-alpha and IFN-gamma. However, MCMV remained undetectable in the lungs during the period. Simultaneous injection of cyclosporin A reduced such effects of anti-CD3. In conclusion, although the presence of MCMV in the host may be required, MCMV-associated pneumonitis is not mediated by virus in the lung but probably by the cytokines released from T cells, of which responsiveness to stimulation via CD3 molecule has been presumably modified by MCMV infection.

The establishment of cytomegalovirus latency in organs is not linked to local virus production during primary infection

Recovery from primary cytomegalovirus (CMV) infection is associated with resolution of the productive infection without clearance of the virus genome from affected organs. The presence of latent CMV genome in multiple organs provides the molecular basis for recurrence of CMV within multiple organs, and explains the diversity in the organ manifestations of recrudescent CMV disease during states of immunodeficiency. As a part of a unifying concept of multifocal CMV latency and recurrence, previous work has demonstrated the importance of primary virus replication for the overall load of latent CMV in organs and the risk of recurrence. In the present report, the establishment of CMV latency was studied in a murine model in which the course of primary infection in the immunocompromised host after syngeneic bone marrow transplantation was modulated by a CD8+ T cell immunotherapy. The antiviral CD8+ effector cells limited virus replication in all organs and protected the recipients from lethal CMV disease, but after resolution of the productive infection virus DNA remained. Interestingly, the copy number of latent virus DNA in tissue did not quantitatively reflect the preceding virus production in the respective organ. Specifically, in contrast to the case in the lungs and the salivary glands, virus replication in the spleen was suppressed by CD8+ T cells to below the limit of detection; yet, virus DNA was also detected in the spleen during latency and accordingly, virus recurrence in the spleen could be induced. These findings demonstrate that the control of virus replication in a particular organ does not prevent the establishment of latency in that organ.

Cervical antibodies in patients with oral herpes simplex virus type 1 (HSV-1) infection: local anamnestic responses after genital HSV-2 infection

Herpes simplex virus (HSV)-specific immunoglobulin A, immunoglobulin G, and secretory-component-containing immunoglobulins were identified in cervical and salivary secretions from six subjects with oral HSV type 1 (HSV-1) infections. Anamnestic cervical and salivary antibody responses were detected in two HSV-1-seropositive women with newly acquired genital HSV-2 infections. These data implicate the common mucosal immune system in antibody responses to HSV.

Effects of UV-B on the resistance against infectious diseases

It is known that ultraviolet-B light (UV-B) affects human health. In addition to deleterious effects on the skin and the eyes, such as erythema, photoageing, keratitis and cataract, UV-B is also able to impair the resistance against skin-associated tumours and infections. Our data implicate that UV-B can impair the resistance against certain non-skin-associated infections in rats, such as Listeria monocytogenes, Trichinella spiralis and Ratcytomegalovirus (RCMV). Rats, infected with T. spiralis, had an increased amount of T. spiralis larvae in their carcasses after UV-B exposure in comparison to control animals, indicating that the resistance to this parasite was decreased by UV-B. Exposure to UV-B caused an increase of RCMV load in the salivary gland 26 days after infection with this virus, indicating that especially the resistance against the second generation of viruses was impaired. In L. monocytogenes-infected rats, UV-B exposure caused an increased number of bacteria in the spleen, coupled to a decreased specific response of T lymphocytes to the bacteria. We conclude that UV-B radiation may affect the resistance against several non-skin-associated infectious diseases, which is probably caused by a defect in the specific lymphocyte response to the antigen.

The secretory cells of mouse salivary glands are nonpermissive for polyomavirus replication

Parotid tumor agent was an early name for polyomavirus due to its ability to induce tumors (myoepitheliomas originating from the myoepithelial glandular tissues) in mice inoculated with polyomavirus (Py) as neonates. It has long been thought that these tumors directly follow productive infection by Py in epithelial cells of the salivary gland, allowing subsequent cellular genetic changes leading to tumor formation. Curiously, the ability of salivary glandular tissue to support Py infection has not been experimentally established. Although Southern analysis for Py DNA has shown virus DNA to be present in whole salivary glands during acute infection, salivary glands are composed of various cell types (myoepithelial glandular cells called serous and mucous cells, fibrocollagenous cells, and interstitial cells), not all of which become transformed. We now use in situ hybridization for Py DNA along with immunohistological and immunohistochemical analyses to show that salivary gland serous and mucous cells are nonpermissive for acute Py infection in Balb/C and C3H mice, but are Py infected, as shown by T-ag expression. Salivary gland fibroblasts and interstitial cells, however, were permissive for Py replication. In addition, isoproterenol and tannin, which induce hypertrophy and hyperplasia of the secretory cells of adult male mice salivary glands, did not make these cells permissive to Py replication.

Expression of sequences homologous to HTLV-I tax gene in the labial salivary glands of Japanese patients with Sjögren's syndrome

OBJECTIVE

To address the question of whether the human T cell leukemia virus type I (HTLV-I) gene is associated with the etiology of Sjögren's syndrome (SS).

METHODS

RNA expression of HTLV-I gag, pol, env, and tax genes in labial salivary glands (LSGs) from SS patients who were seronegative for antibodies to HTLV-I was examined using reverse transcription and polymerase chain reaction techniques.

RESULTS

The HTLV-I tax gene, but not the HTLV-I gag, pol, or env genes, was detected in LSG samples from 4 of 14 patients (29%). The nucleotide sequences of the HTLV-I pXIV region in these 4 patients' LSGs showed 100% homology to the HTLV-I pXIV gene from the MT-2 cell line.

CONCLUSION

These findings suggest that products encoding sequences homologous to the HTLV-I pXIV gene in SS patients' LSGs might be candidates for self-antigen and/or lead to activation of autoreactive T lymphocytes through trans-acting transcriptional activation.

Dissemination and replication of MCMV after supraciliary inoculation in immunosuppressed BALB/c mice

PURPOSE

To study replication and dissemination of murine cytomegalovirus (MCMV) in immunosuppressed (IS) and non-IS BALB/c mice after ocular inoculation via the supraciliary route.

METHODS

BALB/c mice were immunosuppressed by injections of methylprednisolone, and MCMV was injected via the supraciliary route. Ocular and nonocular tissues from both IS and non-IS mice were studied by plaque assay of tissue homogenates. The frequency of virus-positive leukocytes was determined by PCR.

RESULTS

In the inoculated eye, virus replication was significantly higher in both the anterior segment and the posterior segment of IS mice. Virus spread to extraocular sites in both IS and non-IS mice; however, significantly higher titers of virus were recovered from the salivary glands and lungs of IS mice than from non-IS mice, and clearance of virus from these sites was delayed in IS mice. Virus spread from the injected eye via leukocytes, and PCR amplification revealed that the frequency of virus-infected leukocytes was approximately 200-fold higher in IS mice.

CONCLUSIONS

The results of these studies suggest that immunosuppression significantly enhances virus replication in the inoculated eye, salivary glands, and lungs, leads to a higher frequency of virus-positive leukocytes, and delays clearance of virus from ocular and nonocular tissues. These results also suggest that retinitis in the injected eye of IS mice correlates with significantly higher titers of virus in the posterior segment.

The conditions of primary infection define the load of latent viral genome in organs and the risk of recurrent cytomegalovirus disease

Recurrence of cytomegalovirus (CMV) from latency is a frequent cause of disease in immunocompromised patients. To date, there is no explanation for the diversity in the clinical manifestations. Primary infection can occur perinatally or later in life, and inevitably results in latent infection. Seropositivity for antibodies against CMV is indicative of latent infection, but is insufficient as a predictor for the risk of recurrence. As a model for this important medical problem, we compared the risks of murine CMV recurrence from latency established after neonatal primary infection and after infection at adult age. The risk of CMV recurrence was high only after neonatal infection. The copy number of latent viral genome in tissues was identified as the key parameter that determines the overall and organ-specific risks of recurrence. Latent CMV burden and risk of recurrence were related to the extent of virus multiplication during primary infection. The presence of latent CMV in multiple organs provides the molecular basis for stochastic events of recurrence in single organs or in any combination thereof. These findings are discussed as a concept of multifocal CMV latency and recurrence. It provides a rationale for the diversity in the clinical outcome of CMV disease.

Kinetics of infectivity are dissociated from PrP accumulation in salivary glands of Creutzfeldt-Jakob disease agent-inoculated mice

The protease-resistant isoform of prion protein (PrP) has been implicated in the pathogenesis and transmission of Creutzfeldt-Jakob disease (CJD), scrapie and other related diseases, but the relationship between the infectious agent and PrP awaits elucidation. In the present study, we have examined levels of infectivity together with accumulation of the protease-resistant form of PrP (PrPCJD) in various tissues of CJD agent-inoculated mice. Accumulation of PrPCJD occurred only in tissues, including brain, salivary gland and spleen, in which infectivity was readily detectable throughout the course of the experiment. The brain showed the highest levels of both infectivity and PrPCJD accumulation, with well correlated kinetics. On the other hand, the high titres of infectivity detected in salivary gland and spleen early after inoculation of the agent were obviously distinguishable from PrPCJD. Furthermore, in the salivary gland, the kinetics of infectivity and the accumulation of PrPCJD reversed; infectivity declined as PrPCJD accumulated in the tissue. Our findings indicate that PrPCJD accumulation is associated with replication of the agent; however, PrPCJD is unlikely to be the agent itself.

Detection of human T lymphotropic virus type I tax gene in salivary gland epithelium from two patients with Sjögren's syndrome

OBJECTIVE

To investigate whether human T lymphotropic virus type I (HTLV-I) could be involved in the pathogenesis of Sjögren's syndrome (SS).

METHODS

Labial salivary gland (LSG) biopsy specimens from 9 patients with SS (4 with primary SS and 5 with SS secondary to rheumatoid arthritis) and 9 controls were studied for the presence of the tax gene of HTLV-I using in situ hybridization, and for the presence of tax, gag, pol, and env genes of HTLV-I using the polymerase chain reaction (PCR). Testing for antibodies to HTLV-I and examination of lymphocytes on blood smears were performed to determine whether systemic viral infection was present.

RESULTS

Using in situ hybridization and PCR, we detected the tax gene, but not the gag, pol, or env genes, of HTLV-I in LSG sections from 2 of 9 patients with SS and from none of the control subjects. Tax DNA was present mostly in nuclei of epithelial cells, but also in some lymphoid cells. Serum of the 2 affected patients did not contain antibodies to HTLV-I. In 1 patient, examination of blood smears revealed rare convoluted lymphocytes, sometimes with the appearance of "flower cells," as observed in the blood of HTLV-I-infected patients.

CONCLUSION

None of the known endogenous retroviral sequences is homologous to the tax gene. Thus, we suggest that HTLV-I (or another related retrovirus) can infect salivary epithelium. Transactivation properties of the tax protein could be implicated in the pathogenesis of SS. Alternatively, viral infection could cause de novo expression of HLA-DR antigens and favor the presentation of antigens by epithelial cells, leading, in some genetically predetermined subjects, to lymphoid infiltration of the gland.

In vivo effects of fluoride, chlorhexidine and zinc ions on acid formation by dental plaque and salivary mutans streptococcus counts in patients with irradiation-induced xerostomia

Irradiation therapy including major salivary glands may result in xerostomia and enhanced susceptibility to dental caries. The present aim was to assess the ability of mouthrinses with F-, Zn2+, and chlorhexidine (CH), in various combinations, to reduce acidogenic potential of dental plaque and salivary mutans streptococcus counts (SMSC) in 7 patients with xerostomia secondary to irradiation. The patients rinsed twice daily for 3 weeks with the following test solutions: (1) 12 mmol/l NaF (F; control), (2) NaF + 20 mmol/l ZnCl2 (F-Zn), and (3) NaF + 1.1 mmol/l CH (F-CH). Resting periods (F) of varying lengths were incorporated. Acid formation by dental plaque was monitored as plaque pH response to a sucrose mouthrinse, at the end of each test period, 4 h after mouthrinsing with test solution. Plaque pH was measured repeatedly at 2-8 sites in each patient before, and up to 60 min after the sucrose mouthrinse using touch microelectrodes. SMSC were determined using Dentocult SM-Strip mutans. Compared with F, F-CH significantly (P < or = 0.02) reduced acid formation by plaque and SMSC, whereas F-Zn did not affect acid formation or SMSC significantly. Pilot experiments in 4 patients showed mouthrinses with NaF + 0.55 mmol/l CH + 10 mmol/l Zn2+ to be ineffective, whereas NaF + 2.2 mmol/l CH was highly effective, but no better than F-CH. Twice daily mouthrinses with 12 mmol/l NaF in combination with 1.1 mmol/l CH may be an effective regimen to prevent post-irradiation caries.

Cytomegalovirus infection enhances smooth muscle cell proliferation and intimal thickening of rat aortic allografts

Inbred DA (AG-B4, RT1a) and WF (AG-B2, RT1v) rats were used as donors and recipients of aortic allografts. The recipient rats were inoculated i.p. either on day 1 (early infection) or on day 60 (late infection) with 10(5) plaque-forming units of rat cytomegalovirus (RCMV). The control rats were left noninfected. The presence of viral infection was demonstrated by plaque assays from biopsies of the salivary glands, liver, and spleen at sacrifice. The rats received 300 microCi[3H]thymidine by i.v. injection 3 h before sacrifice, and the grafts were removed at various time points for histology, immunohistochemistry, and autoradiography. RCMV infection significantly enhanced the generation of allograft arteriosclerosis. Infection at the time of transplantation had two important effects. First, the infection was associated with an early, prominent inflammatory episode and proliferation of inflammatory cells in the allograft adventitia. Second, the viral infection doubled the proliferation rate of smooth muscle cells and the arteriosclerotic alterations in the intima. In late infection the impact of RCMV infection on the allograft histology was nearly nonexistent. RCMV infection showed no effect in syngeneic grafts. These results suggest that early infection is more important to the generation of accelerated allograft arteriosclerosis than late infection, and that an acute alloimmune response must be associated with virus infection, to induce accelerated allograft arteriosclerosis. RCMV-infected aortic allografts, as described here, provide the first experimental model to investigate the interaction between the virus and the vascular wall of the transplant.