[Clinical, microbiological and therapeutic aspects of oral candidiasis (candidosis)]

Exogenic, prosthetical and endogenic factors that may influence and facilitate fungal infections of the oral cavity are summarized. The clinical classification of the oral candidiasis is based on the criteria accepted in the international literature. The main points for the classification are the clinical appearances, the histopathological alterations and the possible manifestation of an underlying disease. In the last part of the review a brief summary is given on the antifungal agents such as polyenes, azole-derivatives and DNA analogs available for candidiasis.

[Molecular pathogenesis of oral candidiasis (candidosis)]

Candida species are the most important pathogenic fungi in the oral cavity with the predominance of Candida albicans. In this review the authors summarise the most important cell-surface bound pathogenical factors such as fibrinogen, fibronectin, thrombin, collagen, laminin and vitronectin-binding proteins and extracellular virulence enzymes of Candida albicans and some microbiological aspects of oral candidiasis (candidosis). Adherence to both artificial and mucosal surfaces is mediated by hydrophobic interactions and by ligand-receptor attachment. Surface bound proteins on Candida cells bind to mucosal surface proteins. Broad spectrum antibacterial treatment liberates binding sites for Candida colonisation by means of reducing the number of bacterial normal flora in the oral cavity. Non immune humoral factors such as iron, lysosyme, hystidine-rich-polypeptides, lactoferrin, lactoperoxidase and immune globulins such as s-IgA, moreover, elements of cellular immunity, especially polymorphonuclear leucocytes contribute to preventing the establishment of Candida infection. A disbalance in these constituents may result in colonisation and biofilm production of Candida. The biofilm consist of serum proteins mainly fibrin, desquamated epithelial cells, dead leukocytes, living and multiplying candida cells, pseudohyphae and extracellular matrix excreted by candida cells. Living candida cells are deeply embedded in the biofilm, thus protected from defence mechanisms of the host. Continuous destruction of mucosal surfaces beneath the biofilm may create a portal of entry for systematic candidal infections.

Risk group assessment of oral precancer attached to X-ray lung-screening examinations

The mortality rate of oral tumours in Hungary, as in some other countries, is increasing. In order to assess risk groups for oral cancer and precancer, oral examinations were carried out as part of the X-ray screenings for lung cancer in the 3rd district of Budapest, Hungary. There were 5,034 adults who participated voluntarily in these investigations. After completing a questionnaire with 23 questions, a short oral examination was performed. Males comprised 57.7% of the group, and the age-distribution among men and women was similar. Oral precancerous lesions were found in 3.7% of the whole group, in 3.3% of those with leukoplakia, and in 0.4% of those with oral lichen planus. The prevalence of leukoplakia in men was 5.8%, and in women 1.5%, with significantly higher prevalences in men and women over 40. Among the examined persons there were 31% who were smokers, and 6% reported that they were regular consumers of alcohol. Fifty-four percent of those examined reported that they did not visit the dentist regularly. Oral complaints came mostly from those with lichen planus. The described model, where the oral screening examinations are done in conjunction with other examinations, in a so-called multiphasic screening system, seems to be a worthwhile approach for early diagnosis of oral cancer and precancer.

Identification of CRAM, a novel unc-33 gene family protein that associates with CRMP3 and protein-tyrosine kinase(s) in the developing rat brain

Four members of collapsin response mediator proteins (CRMPs) are thought to be involved in the semaphorin-induced growth cone collapse during neural development. Here we report the identification of a novel CRMP3-associated protein, designated CRAM for CRMP3-associated molecule, that belongs to the unc-33 gene family. The deduced amino acid sequence reveals that the CRAM gene encodes a protein of 563 amino acids, shows 57% identity with dihydropyrimidinase, and shows 50-51% identity with CRMPs. CRAM appears to form a large complex composed of CRMP3 and other unidentified proteins in vivo. Indeed, CRAM physically associates with CRMP3 when co-expressed in COS-7 cells. The expression of CRAM is brain-specific, is high in fetal and neonatal rat brain, and decreases to very low levels in adult brain. Moreover, CRAM expression is up-regulated during neuronal differentiation of embryonal carcinoma P19 and PC12 cells. Finally, immunoprecipitation analysis of rat brain extracts shows that CRAM is co-immunoprecipitated with proteins that contain protein-tyrosine kinase activity. Taken together, our results suggest that CRAM, which interacts with CRMP3 and protein-tyrosine kinase(s), is a new member of an emerging family of molecules that potentially mediate signals involved in the guidance and outgrowth of axons.

Distinctive functions of Syk N-terminal and C-terminal SH2 domains in the signaling cascade elicited by oxidative stress in B cells

Syk plays a crucial role in the transduction of oxidative stress signaling. In this paper, we investigated the roles of Src homology 2 (SH2) domains of Syk in oxidative stress signaling, using Syk-negative DT40 cells expressing the N- or C-terminal SH2 domain mutant [mSH2(N) or mSH2(C)] of Syk. Tyrosine phosphorylation of Syk in cells expressing mSH2(N) Syk after H(2)O(2) treatment was higher than that in cells expressing wild-type Syk or mSH2(C) Syk. The tyrosine phosphorylation of wild-type Syk and mSH2(C) Syk, but not that of mSH2(N), was sensitive to PP2, a specific inhibitor of Src-family protein-tyrosine kinase. In oxidative stress, the C-terminal SH2 domain of Syk was demonstrated to be required for induction of tyrosine phosphorylation of cellular proteins, phospholipase C (PLC)-gamma2 phosphorylation, inositol 1,4, 5-triphosphate (IP(3)) generation, Ca(2)(+) release from intracellular stores, and c-Jun N-terminal kinase activation. In contrast, in mSH2(N) Syk-expressing cells, tyrosine phosphorylation of intracellular proteins including PLC-gamma2 was markedly induced in oxidative stress. The enhanced phosphorylation of mSH2(N) Syk and PLC-gamma2, however, did not link to Ca(2)(+) mobilization from intracellular pools and IP(3) generation. Thus, the N- and C-terminal SH2 domains of Syk possess distinctive functions in oxidative stress signaling.

Purification of a 72-kDa protein-tyrosine kinase from rat liver and its identification as Syk: involvement of Syk in signaling events of hepatocytes

Syk protein-tyrosine kinase (PTK) has been implicated in a variety of hematopoietic cell responses including immunoreceptor signaling. However, so far, there has been no evidence of the expression of Syk or Syk-related PTK in non-hematopoietic tissues. In this study, we have purified from blood cell-depleted rat liver a 72-kDa cytoplasmic PTK which shows cross-reactivity with anti-Syk antibody. Partial amino acid sequence analysis revealed that this 72-kDa PTK is identical to Syk. Immunohistochemical and RT-PCR analyses demonstrated that Syk is expressed in human hepatocytes and two rat liver-derived cell lines, JTC-27 and RLC-16. Furthermore, Syk is significantly tyrosine-phosphorylated in response to angiotensin II in JTC-27 cells, and angiotensin II-induced MAP kinase activation is blocked by the treatment of cells with a Syk-selective inhibitor, piceatannol. These results suggest that Syk plays an important role in signaling events of hepatocytes, such as signaling steps leading to MAP kinase activation by G-protein-coupled receptors. This is the first report of the expression of Syk in non-hematopoietic tissue.

The vitronectin receptor and its associated CD47 molecule mediates proinflammatory cytokine synthesis in human monocytes by interaction with soluble CD23

The vitronectin receptor, alphavbeta3 integrin, plays an important role in tumor cell invasion, angiogenesis, and phagocytosis of apoptotic cells. CD47, a member of the multispan transmembrane receptor family, physically and functionally associates with vitronectin receptor (VnR). Although vitronectin (Vn) is not a ligand of CD47, anti-CD47 and beta3 mAbs suppress Vn, but not fibronectin (Fn) binding and function. Here, we show that anti-CD47, anti-beta3 mAb and Vn, but not Fn, inhibit sCD23-mediated proinflammatory function (TNF-alpha, IL-12, and IFN-gamma release). Surprisingly, anti-CD47 and beta3 mAbs do not block sCD23 binding to alphav+beta3+ T cell lines, whereas Vn and an alphav mAb (clone AMF7) do inhibit sCD23 binding, suggesting the VnR complex may be a functional receptor for sCD23. sCD23 directly binds alphav+beta3+/CD47(-) cell lines, but coexpression of CD47 increases binding. Moreover, sCD23 binds purified alphav protein and a single human alphav chain CHO transfectant. We conclude that the VnR and its associated CD47 molecule may function as a novel receptor for sCD23 to mediate its proinflammatory activity and, as such, may be involved in the inflammatory process of the immune response.

OX40 costimulation enhances interleukin-4 (IL-4) expression at priming and promotes the differentiation of naive human CD4(+) T cells into high IL-4-producing effectors

Th2 cell development is critically dependent on the presence of interleukin-4 (IL-4) at priming. The cellular origin and the mechanisms regulating this early production of IL-4 at the site of naive T-cell priming are extensively investigated. We previously reported that anti-CD3-activated and CD28-costimulated naive human CD4(+) T cells themselves release very low but sufficient levels of IL-4 to support their development into high IL-4-producing cells. We show here that ligation of OX40 Ag, a member of the tumor necrosis factor receptor (TNF-R) family, on activated umbilical cord blood CD4(+) T cells upregulates IL-4 production at priming and thereby promotes their development into effector cells producing high levels of the type 2 cytokines IL-4, IL-5, and IL-13. OX40 ligation increases four times the expression of IL-4 mRNA after 48 hours of anti-CD3/B7.1 activation and significantly augments the release of IL-4 and IL-13 in primary cultures. The effects of OX40 costimulation on Th cell differentiation are observed in the presence of optimal and suboptimal CD28 stimulation. Because OX40 ligand is expressed on dendritic cells, the OX40 costimulation pathway may be involved in the physiological regulation of Th cell development by augmenting the differentiation of IL-4-producing cells.

IFN-alpha priming of human monocytes differentially regulates gram-positive and gram-negative bacteria-induced IL-10 release and selectively enhances IL-12p70, CD80, and MHC class I expression

Administration of IFN-gamma and IFN-alpha may protect or induce autoimmune diseases. Although the in vitro regulation of monokine secretion by IFN-gamma have been extensively studied, the regulatory function of IFN-alpha has not yet been elucidated. We compared IFN-alpha and IFN-gamma, added alone or simultaneously before bacterial stimulation, for the control of monokine release and the expression of costimulatory molecules by human monocytes. Our data show that: 1) IFN-alpha primes monocytes for increased production of IL-10 in response to Staphylococcus aureus Cowan I strain (SAC) but not to LPS, leading to a lack of IFN-alpha priming for TNF-alpha secretion; 2) pretreatment of monocytes with IFN-alpha inhibits LPS- or SAC-induced IL-12p40 production but unexpectedly enhances the release of the biologically active form of IL-12 (IL-12p70); 3) IFN-alpha and IFN-gamma exert an antagonistic effect on LPS- and SAC-induced IL-10 as well as IL-12p40 release, whereas they further enhance IL-12p70 production when added simultaneously; 4) in contrast to IFN-alpha, IFN-gamma primes monocytes to enhance LPS- or SAC-induced TNF-alpha and IL-12 production, but surprisingly, it increases IL-10 production by monocytes following LPS but not SAC stimulation; and finally, 5) IFN-alpha pretreatment selectively up-regulates CD80 and MHC class I expression on monocytes. It is proposed that the outcome of the immune response at the site of inflammation may depend on both the type of bacterial injury (gram-positive or -negative) and of locally produced IFNs, and that the differential and opposite effects of type I and type II IFNs on monocytes may account for the beneficial or detrimental effects of IFN-alpha therapy.

Blood and cerebral concentrations of the new potential analgesic UP 26-91 measured in vivo by microdialysis after toxic doses

The concept of proportionality between the pharmacological effects of drugs and their dosage has been questioned since the discovery of saturable phenomenon for some drug dispositions, either during their absorption or their elimination. Such saturation may also occur during the distribution phase in the tissues. This phenomenon, however, is often difficult to demonstrate and microdialysis is a powerful technique to assess precise changes in drug concentrations in tissue. This technique has been used to compare brain and blood concentrations of a potential analgesic, UP 26-91 (3-¿[2-[4-(2,4-difluorophenyl)piperazin-1-yl]ethyl]thio¿ -1,2,4-triazolo[4,3-a]pyrioline, citrate salt, CAS 115762-17-9 for the base), at different intravenous doses. Microdialysis probes were surgically implanted in the cerebral cortex and the jugular vein of male Sprague-Dawley rats (about 350 g). A single dose of radiolabelled 14(C) UP 26-91 mixed with unlabelled drug was injected into the animal's tail vein. Three doses of drug (2.5, 12.5 and 22.5 mg.kg-1) were tested, with three rats for each dose. All the doses consisted of the same amount of radiolabelled product, used as a tracer, supplemented by the amount of non-radiolabelled UP 26-91 necessary to reach the desired concentration. The rats were conscious, freely moving and had free access to food and water. Microdialysis samples were collected at the rate of 1 microliter.min-1, and sampled every 15 min for 16-17 h. The two highest doses were in the range of those used for toxicological studies. Blood UP 26-91 radioactivity concentrations were superimposable independent of the dose. Thus, it can be concluded that there was a linear relationship between blood concentrations and administered doses. By contrast, the brain concentration for the highest administered dose was statistically higher than the two others (p < 0.05), which demonstrated that UP 26-91 exhibited a non-linear pharmacokinetics in the brain. It is therefore likely that a saturable transport mechanism occurs across the blood-brain barrier. This study demonstrates that blood toxicokinetics may not correctly reflect tissue exposure to a drug.

Enterohepatic recirculation of the new antihypertensive drug UP 269-6 in humans. A possible model to account for multiple plasma peaks

Following a single dose of a new antihypertensive drug, UP 269-6 (5-methyl-7-propyl-8-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl)methyl]-1,2,4-triazolo[1,5-c]pyrimidin-2(3H)-one, CAS 148504-51-2), to 12 healthy volunteers, the plasma levels showed at least two secondary peaks. To explain this observation, the data were fitted to a new compartmental model of enterohepatic recirculation, without using a numerical method. Most subjects exhibited two cycles of recirculation. The amount of drug involved in each recirculation was calculated and the AUCs compared. The drug showed high biliary excretion and reabsorption.

CD40 ligand-positive CD8+ T cell clones allow B cell growth and differentiation

A fraction of activated CD8+ T cells expresses CD40 ligand (CD40L), a molecule that plays a key role in T cell-dependent B cell stimulation. CD8+ T cell clones were examined for CD40L expression and for their capacity to allow the growth and differentiation of B cells, upon activation with immobilized anti-CD3. According to CD40L expression, CD8+ clones could be grouped into three subsets. CD8+ T cell clones expressing high levels of CD40L (> or = 80% CD40L+ cells) were equivalent to CD4+ T cell clones with regard to induction of tonsil B cell proliferation and immunoglobulin (Ig) production, provided the combination of interleukin (IL)-2 and IL-10 was added to cultures. CD8+ T cell clones, with intermediate levels of CD40L expression (10 to 30% CD40L+ cells), also stimulated B cell proliferation and Ig secretion with IL-2 and IL-10. B cell responses induced by these CD8+ T cell clones were neutralized by blocking monoclonal antibodies specific for either CD40L or CD40. By contrast, CD40L- T cell clones (< or = 5% CD40L+ cells), only induced marginal B cell responses even with IL-2 and IL-10. All three clone types were able to activate B cells as shown by up-regulation of CD25, CD80 and CD86 expression. A neutralizing anti-CD40L antibody indicated that T cell-dependent B cell activation was only partly dependent on CD40-CD40L interaction. These CD40L- clones had no inhibitory effects on B cell proliferation induced by CD40L-expressing CD8+ T cell clones. Taken together, these results indicate that CD8+ T cells can induce B cell growth and differentiation in a CD40L-CD40-dependent fashion.

Who are the primary caretakers of children born to HIV-infected mothers? Results from a multistate surveillance project

OBJECTIVE

To determine the primary caretakers of children born to women with human immunodeficiency virus (HIV) infection.

METHODS

We interviewed women at least 18 years of age who have been reported with HIV infection or acquired immunodeficiency syndrome to local health departments in 10 cities and states regarding the primary caretaker of their children born since 1977.

RESULTS

Of 541 HIV-infected women who had been pregnant since 1977, 88% had living children. These women comprised 478 family units (mother and children); 234 (49%) of these units consisted of two or more children. The most common primary caretakers for all children within a family unit were the mother alone (46%), grandparents (16%), and both mother and father (15%). When the mother used injection drugs or lived alone, in a shelter, or with friends, almost one quarter of all children were cared for by their grandparents. Only 30% of the mothers knew about child care assistance services, and only 8% had contacted or used these services.

CONCLUSIONS

Mothers with HIV, often alone, are the primary caretakers of their children. Increased provisions for child care assistance and planning for future permanent placement of orphaned children are urgently needed.

THE NEURAL CONTROL OF EGG-LAYING BEHAVIOUR IN THE POND SNAIL LYMNAEA STAGNALIS: MOTOR CONTROL OF SHELL TURNING

Behavioural and neurophysiological techniques were used to study the neuronal control of shell turning during egg-laying in the pond snail Lymnaea stagnalis. Egg-laying consists of three phases: resting, turning and oviposition, and is triggered by an electrical discharge in a group of neuroendocrine cells, the caudodorsal cells. During the discharge, several peptides encoded on two CDCH genes are known to be released. Behavioural experiments in which different combinations of nerves were lesioned indicated that the inferior cervical nerves are necessary for turning behaviour to occur. The right inferior cervical nerve innervates the right dorsal longitudinal muscle and contains axons of neurones that are active just prior to, and during, shell movements in freely behaving animals. These axons are probably the axons of motor neurones. The motor neurones of the dorsal longitudinal muscle were identified in the cerebral A and pedal N clusters. We have demonstrated that there is a correlation between the state of excitability of the caudodorsal cells and the electrical activity of the pedal N motor neurones. Our results indicate that the pedal N motor neurones are involved in executing the turning phase during egg-laying.

[Microbiological study of the correlation between pontics and their mucosal and bone bases]

Authors investigated the possible relationship between different types of ponties and the development of dental plaque. Microbiological examinations revealed, that keeping to the strictest hygiene rules, even the least proposed saddle ponties should be omitted. Attention is called to the utmost importance of motivation and instruction in case of patients wearing bridges.

[Anchoring of partial dentures using OT-CAP precision attachments]

The authors have examined a precision attachment recently invented in Hungary. They are reporting about the experience gained during clinical examination of dentures made in different classes on the basis of the Fábián and Fejérdy classification of partial edentulousness.

Risk behaviors of persons with heterosexually acquired HIV infection in the United States: results of a multistate surveillance project

To describe past risk behaviors among persons with heterosexually acquired human immunodeficiency virus (HIV) infection, we interviewed 497 persons > or = 18 years of age with heterosexually acquired HIV infection reported to 11 state and city health departments in the United States. Thirty-nine percent of persons reported using noninjection drugs in the past 5 years; noninjection drug use was highest among men whose sex partners injected drugs (53%). Sixteen percent of all persons used crack, and 17% were classified as potential alcoholics; among men, 29% were classified as potential alcoholics. Of the 49% of men who reported paying a woman for sex, 86% did so multiple times. Most persons had multiple sex partners in the past 5 years; however, 35% of the women had only one sex partner. Thirty-four percent of the women and 50% of the men had been treated for a sexually transmitted disease in the past 10 years. Seventy-four percent of the women and 68% of the men had never used condoms in the 5 years before they knew they were HIV positive. Among these people with heterosexually acquired HIV, noninjection drug use was common, many men have paid someone for sex, and many women have not had multiple sex partners. These findings have important implications for the types of prevention programs that can most successfully lessen the spread of HIV among heterosexuals.

Socioeconomic differences among people with AIDS: results from a Multistate Surveillance Project

To characterize the socioeconomic status of persons with acquired immunodeficiency syndrome (AIDS), 11 U.S. state and city health departments interviewed 2,898 persons > or = 18 years of age reported with AIDS between June 1, 1990, and January 31, 1993. Among men who have sex with men, white men reported the lowest percentage (9%), and Central/South American (50%) and Mexican men (40%) reported the highest percentages not completing 12 years of school. Among intravenous drug users (IDUs), 35% of white men, 64% of black men, 67% of Puerto Rican men, 29% of white women, and 63% of black women had not completed 12 years of school. Overall, 77% of the men and 90% of the women were unemployed; we also found racial/ethnic differences by employment but to a lesser degree than differences in education. Among women, but not among men, differences in household income by race and ethnicity were marked; 76% of white and 91% of black female IDUs reported a household income of $10,000. Human immunodeficiency virus (HIV) prevention programs must be targeted toward the educational level of the populations served, and HIV services must adapt to the financial circumstances of their clientele.

B cells regulate expression of CD40 ligand on activated T cells by lowering the mRNA level and through the release of soluble CD40

The expression of CD40 ligand (CD40L) on activated T cells (CD4+ T cell clone MT9) is diminished when the T cells are cultured in the presence of B cells. This effect, observed both with normal tonsil B cells and with the B cell line JY, was detected after 6 h and sustained at least until 18 h of co-culture. Analysis of mRNA showed that CD40L mRNA levels were not modified after 6 h, but were significantly down-regulated after 18 h of co-culture with B cells. Although CD40L expression could not be detected by a CD40-Fc chimera, the molecule was still expressed at the membrane as shown with a polyclonal antiserum against CD40L (anti-TRAP). In addition, T cells activated in the presence of B cells were stained by a polyclonal antiserum against CD40, without the appearance of CD40 mRNA. These results indicated that a soluble form of CD40 (sCD40) bound to the expressed CD40L on T cells. The existence of sCD40 was confirmed by detection of sCD40 in B cell supernatants using a specific enzyme-linked immunosorbent assay. Collectively, these data show that B cells can regulate the expression of CD40L on activated T cells at least by two different mechanisms.