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Prophylaxis of radiation-associated mucositis in conventionally treated patients with head and neck cancer: a double-blind, phase III, randomized, controlled trial evaluating the clinical efficacy of an antimicrobial lozenge using a validated mucositis scoring system.

PURPOSE: Mucositis occurs in almost all patients treated with radiotherapy for head and neck cancer. The aim of this multicenter, double-blind, prospective, randomized trial was to evaluate the clinical efficacy of an economically viable antimicrobial lozenge (bacitracin, clotrimazole, and gentamicin [BcoG]) in the alleviation of radiation-induced mucositis in patients with head and neck cancer. PATIENTS AND METHODS: One hundred thirty-seven eligible patients were randomized to treatment with either antimicrobial lozenge (69 patients) or placebo lozenge (68 patients). The primary end point of the study was the time to development of severe mucositis from the start of radiotherapy. Secondary end points included severity and duration of mucositis, pain measurement, radiation therapy interruption, and quality of life. Mucositis was scored using a validated mucositis scoring system. RESULTS: Toxicity profiles were similar between the two arms of the study. The median time to development of severe mucositis from the start of radiotherapy was 3.61 weeks on BCoG and 3.96 weeks on placebo (P =.61). There were no statistically significant differences between the arms in the extent of severe mucositis as measured by physician, in oral toxicities as recorded by patients, or in radiotherapy delays. CONCLUSION: This study was conducted on the basis of a pilot study that demonstrated the BCoG lozenge to be tolerable and microbiologically efficacious. A validated mucositis scoring system was used. However, in this group of patients treated with conventional radiotherapy, the lozenge did not impact significantly on the severity of mucositis. Whether such a lozenge would be beneficial in treatment situations where rate of severe mucositis is higher (ie, in patients treated with unconventional fractionation or with concomitant chemotherapy) is unknown.

Administration, Oral↗

[A study on pathogenesis of gastric mucosal lesions in hemodialysis patients, with special reference to the gastric mucosal blood flow].

Clinical characteristics of gastric mucosal lesions in hemodialysis patients were studied. The relationships between the occurrence of gastric mucosal lesions and changes of gastric mucosal blood flow were studied in normal subjects and hemodialysis patients to clarify causes of gastric mucosal lesions in them. Erosive gastritis, gastric ulcers and hemorrhagic gastritis were the main manifestations of the lesions in hemodialysis patients. The lesions were mainly localized in the gastric antrum. Hemorrhagic gastritis lesions were also found in the gastric body as well as in the gastric antrum. The gastric mucosal blood flow in the gastric body showed lower values than in healthy controls while gastric mucosal blood flow in the antrum revealed no such significant difference. Therefore, it can be considered that the low value of gastric mucosal blood flow in the gastric body may contribute to the occurrence of gastric mucosal lesions in the gastric body in hemodialysis patients. However, gastric mucosal lesions in hemodialysis patients were localized mainly in the gastric antrum, and, accordingly, the changes in the gastric mucosal blood flow are not supposed to account for the lesions in the gastric antrum. Further studies are, therefore, required to clarify the causes of gastric mucosal lesions in hemodialysis patients.

Adult↗

Validation of a new scoring system for the assessment of clinical trial research of oral mucositis induced by radiation or chemotherapy. Mucositis Study Group.

BACKGROUND: An impediment to mucositis research has been the lack of an accepted, validated scoring system. The objective of this study was to design, test, and validate a new scoring system for mucositis that can be used easily, is reproducible, and provides an accurate system for research applications. METHODS: A panel of experts, convened to design an objective, simple, and reproducible assessment tool to evaluate mucositis with specific application to multicenter clinical trials, developed a scale that measured objective and subjective indicators of mucositis. Nine centers participated in the study's validation. Paired investigators at each center evaluated patients receiving chemotherapy or head and neck radiation. Objective measures of mucositis evaluated ulceration/pseudomembrane formation and erythema. Subjective outcomes of mouth pain, ability to swallow, and function were measured. Analgesia use for mouth sensitivity was recorded. RESULTS: One hundred eight chemotherapy and 56 radiation therapy patients were evaluated. Seventy-eight percent of chemotherapy patients and 64% of radiation therapy patients had clinically significant mucositis. Cumulative daily mucositis scores demonstrated a high correlation among observers. Using area under the curve analysis, it was found that for chemotherapy patients, the highest correlations (correlation coefficient > 0.92) occurred for the scores that selected the three highest daily values over the course of mucositis assessment. High interobserver correlations were noted for patients receiving radiation therapy. Objective mucositis scores demonstrated strong correlation with symptoms. CONCLUSIONS: The scoring system evaluated was easily used, showed high interobserver reproducibility, was responsive over time, and measured those elements deemed to be associated with mucositis. The use of concomitant symptomatic measurements appeared to be unnecessary.

Adult↗

Long-lived cytotoxic T lymphocyte memory in mucosal tissues after mucosal but not systemic immunization.

The induction and maintenance of long-term CTL memory at mucosal surfaces may be a critical component of protection against mucosal pathogens and is one goal towards development of effective mucosal vaccines. In these studies we have functionally evaluated short and long-term CTL memory in systemic and respiratory or genital-associated lymphoid tissues following mucosal or systemic routes of immunization. Our results indicate that shortly after immunizing mice with a recombinant adenovirus vector expressing glycoprotein B (gB) of herpes simplex virus (AdgB8), gB-specific CTL memory responses were observed in systemic and mucosal immune compartments regardless of the route of inoculation. In contrast, several months after immunization, anamnestic CTL responses compartmentalized exclusively to mucosal or systemic lymphoid tissues after mucosal or systemic immunization, respectively. Furthermore, the compartmentalized CTL memory responses in mucosal tissues were functionally observed for longer than 1.5 yr after intranasal immunization, and CTL precursor frequencies one year after immunization were comparable to those seen shortly after immunization. Therefore, to our knowledge, this is the first functional demonstration that the maintenance of anti-viral memory CTL in mucosal tissues is dependent on the route of immunization and the time of assessment. These results have important implications for our understanding of the development, maintenance, and compartmentalization of functional T cell memory and the development and evaluation of vaccines for mucosal pathogens, such as HSV and HIV.

Animals↗

A prospective randomized trial of either famotidine or omeprazole for the prevention of bleeding after endoscopic mucosal resection and the healing of endoscopic mucosal resection-induced ulceration.

BACKGROUND: It has been reported that inhibitors of gastric acid secretion prevent bleeding after endoscopic mucosal resection for mucosal gastric neoplasm. However, uncertain whether an histamine2-receptor antagonist or proton-pump inhibitor is more effective. AIM: To evaluate prospectively the effectiveness of famotidine or omeprazole for ulcer management after endoscopic mucosal resection. METHODS: From July 2003 to October 2004, 57 patients were randomly assigned to famotidine or omeprazole for the management of endoscopic mucosal resection. Both drugs were given intravenously for the first 2 days, thereafter by mouth. The bleeding rates after endoscopic mucosal resection, the effects on the healing of endoscopic mucosal resection-induced ulceration, and cost-benefits were compared. RESULTS: Twenty-eight patients received famotidine and 29 received omeprazole. No significant difference was observed between the two groups in patient characteristics. The bleeding rates after endoscopic mucosal resection were not significantly different (18% vs. 14%) between the groups. Similarly, no differences were seen in the size of the endoscopic mucosal resection-induced ulceration at 1, 30 and 60 days after resection between groups. The total costs of anti-secretory agents demonstrated a significant cost-benefit to those treated with famotidine (10,420 yen vs. 17,782 yen). CONCLUSIONS: Famotidine is suggested as a better alternative to omeprazole for the management of endoscopic mucosal resection, as it showed a clear cost-benefit, and the healing results after endoscopic mucosal resection were similar for the two treatment strategies.

Aged↗

Mucosal adaptation to aspirin induced gastric damage in humans. Studies on blood flow, gastric mucosal growth, and neutrophil activation.

The gastropathy associated with the ingestion of non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin is a common side effect of this class of drugs, but the precise mechanisms by which they cause mucosal damage have not been fully explained. During continued use of an injurious substance, such as aspirin, the extent of gastric mucosal damage decreases and this phenomenon is named gastric adaptation. To assess the extent of mucosal damage by aspirin and subsequent adaptation the effects of 14 days of continuous, oral administration of aspirin (2 g per day) to eight healthy male volunteers was studied. To estimate the rate of mucosal damage, gastroscopy was performed before (day 0) and at days 3, 7, 14 of aspirin treatment. Gastric microbleeding and gastric mucosal blood flow were measured using laser Doppler flowmeter and mucosal biopsy specimens were taken for the estimation of tissue DNA synthesis and RNA and DNA concentration. In addition, the activation of neutrophils in peripheral blood was assessed by measuring their ability to associate with platelets. Aspirin induced acute damage mainly in gastric corpus, reaching at day 3 about 3.5 on the endoscopic Lanza score but lessened to about 1.5 at day 14 pointing to the occurrence of gastric adaptation. Mucosal blood flow increased at day 3 by about 50% in the gastric corpus and by 88% in the antrum. The in vitro DNA synthesis and RNA concentration, an index of mucosal growth, were reduced at day 3 but then increased to reach about 150% of initial value at the end of aspirin treatment. It is concluded that the treatment with aspirin in humans induces gastric adaptation to this agent, which entails the increase in mucosal blood flow, the rise in neutrophil activation, and the enhancement in mucosal growth.

Adaptation, Physiological↗

Mucosal immunization with HIV-1 peptide vaccine induces mucosal and systemic cytotoxic T lymphocytes and protective immunity in mice against intrarectal recombinant HIV-vaccinia challenge.

Mucosal tissues are major sites of HIV entry and initial infection. Thus, the induction of a mucosal cytotoxic T lymphocyte (CTL) response is an important feature for an effective HIV vaccine. However, little is known about approaches to induce such a protective CTL response in the mucosa. Here for the first time we show that intrarectal immunization with a synthetic, multideterminant HIV peptide plus cholera toxin adjuvant induced long-lasting, antigen-specific CTL memory in both the inductive (Peyer's patch) and effector (lamina propria) mucosal sites, as well as in systemic sites (spleen), whereas systemic immunization induced specific CTL only in the spleen. Cholera toxin adjuvant, while enhancing the response, was not essential. The CTL recognized target cells either pulsed with HIV peptide or expressing endogenous whole envelope glycoprotein of Mr 160,000 (gp160). Exploring the requirements for CTL induction, we show that mucosal CTL responses are both interleukin 12 and interferon-gamma dependent by using antibody-treated and knock-out mice. Finally, to determine whether a mucosal response is actually protective against local mucosal challenge with virus, we show that intrarectal immunization with the synthetic HIV peptide vaccine protected mice against infection via mucosal challenge with a recombinant vaccinia virus expressing HIV-1IIIB gp160. These studies provide an approach to development of an HIV vaccine that induces CTL immunity in the mucosal and systemic immune systems and protects against mucosal infection with a virus expressing HIV-1 gp160.

AIDS Vaccines↗

Effects of resuscitation on acute gastric mucosal injury: reperfusion injury versus rapid mucosal restitution.

Gastric mucosal injury after hemorrhagic shock may be a consequence of both ischemia and reperfusion, as toxic oxygen-derived compounds are generated when ischemic tissues are reperfused. The present study was designed to estimate the magnitude of the reperfusion component of gastric mucosal injury, in comparison with the known capacity of the gastric mucosal surface to rapidly restore or restitute its surface after removal of various insults. Twelve dogs were subjected to 2 hr of hemorrhagic shock, with intragastric acid infused to produce gastric mucosal injury. Half were sacrificed 15 min after return of shed blood, while half were fully resuscitated with additional crystalloids and sacrificed 2 hr later. Gross and microscopic injury to the gastric mucosal surface were not increased by resuscitation. Particularly in the antrum, the resuscitated animals had significantly less gastric mucosal injury than unresuscitated animals. The amount of gastric mucosal injury was strongly inversely related to the success of resuscitation after 2 hr, specifically correlating with left ventricular pressure, cardiac index, mean arterial pressure, and systemic pH. Our data suggest that gastric mucosal restitution rather than reperfusion injury may predominant within a few hours of hemorrhagic shock and show that the degree of shock-induced gastric mucosal injury is inversely related to hemodynamic performance after resuscitation.

Animals↗

Influence of mucosal cell origin on the in vitro adherence of Candida albicans: are mucosal cells from different sources equivalent?

The influence of collecting mucosal cells from various anatomical sites, and varying the date of collection and cell donor on adhesion of Candida albicans to human epithelial cells was examined by using an in vitro adherence assay. Examination of buccal mucosal cells from twenty-four donors showed statistically significant differences in the number of attached yeasts between individuals. Sex did not exert a significant influence on adhesion. Examination of buccal mucosal cells from ten donors collected on five different dates revealed that yeast attachment to mucosal epithelial cells varied significantly within subjects across time. Epithelial cells from some donors manifested greater date-to-date variations in yeast adhesion than others. Adherence of Candida to mucosal cells from three anatomical sites (mouth, vagina and urinary tract) collected from ten different donors was also tested. Yeast adherence to buccal cells was highest, lowest using urinary tract cells, while vaginal epithelium was intermediate. Adherence to mucosal cells from three sites was significantly different both within and between individuals although some subjects manifested larger variations than others. These data suggest that the in vitro adherence of Candida albicans is influenced by mucosal cell donor, date of collection and body site of origin. Mucosal cells from different sources do not appear to be equivalent in receptiveness to C. albicans and this might explain some of the discrepancies observed when adhesion studies performed by different investigators are compared. The existing need for a more uniform methodology with which to pursue studies on fungal attachment to mucosal surfaces is emphasized.

Adhesiveness↗

Effect of neutropenia on gastric mucosal integrity and mucosal nitric oxide synthesis in the rat.

UNLABELLED: The present study examined the interaction between neutrophils and gastric mucosal nitric oxide (NO) synthesis in the regulation of gastric mucosal integrity in the rat. Male Sprague-Dawley rats were made neutropenic by intraperitoneal injections of methotrexate (MT; 2.5 mg/kg) or antineutrophil serum (ANS; 100 microliters). Control rats were treated with saline. Neutropenia was confirmed by circulating neutrophil counts and tissue myeloperoxidase activity. Neutropenic or control rats were given 2 ml of ethanol (EtOH; 40% w/v intragastrically). Neutropenic rats were less susceptible to EtOH-induced mucosal damage when compared to control rats. Mucosal NO synthesis was increased in neutropenic rats. EtOH instillation reduced NO synthase in control rats. However, in MT-treated rats the reduced NO synthase activity was not different from that observed in untreated control rats. CONCLUSIONS: (1) EtOH-mediated gastric mucosal injury appears to be a neutrophil-mediated process. (2) Neutropenia results in an increase in mucosal NO synthesis. (3) MT treatment augments the degree of mucosal integrity. The increase in integrity is associated with a reduction in mucosal neutrophil infiltration as well as maintenance of NO synthase activity. ANS appears to influence mucosal integrity primarily by a reduction in circulating neutrophils.

Amino Acid Oxidoreductases↗

[The value of the thermocouple in the measurement of the gastric mucosal blood-flow. The influence of the occlusion of the celiac artery and prostaglandin E1 on the gastric mucosal blood flow. An experimental study in animals (author's transl)].

The study has been carried out to ensure the positive evidence of the measurement of the gastric mucosal blood-flow with the aid of the thermocouple (heat-clearance technique). The experiments have shown that the suction pressure of 600 mm mercury column which was used to fix the Thermocouple to the mucosa was indispensable in order to assess the blood-flow in the entire depth of the mucosa. Changes in the mucosal blood-flow are measuured at the same rate in all quadrants of the gastric corpus. The measuring of the blood-flow of a well circumscribed area of the mucosa is therefore representative for the entire corpus. Vasopressin led to a significant reduction of the gastric mucosal blood-flow measured with heat-clearance as well aminopyrine-clearance. There was a linear correlation between the results of both methods. Vasopressin selectively reduces the blood-flow of the gastric mucosa but not of the submucosa, the muscular layer and the serosa. Therefore it seems to be probable that changes in mucosal blood-flow selectively can be measured with the aid of the thermocouple. After previous stimulation with pentagastrin neither mucosal blood-flow nor acid secretion of the stomach were influenced by the occlusion of the celiac artery by 25 %. The occlusion of the celiac artery by 50 % reduced significantly the pentagastrin-stimulated gastric mucosal blood-flow whereas the acid secretion was not influenced. Prostaglandin E1 at a dose rate of 2 mug/kg-h increased significantly arterial and mucosal blood-flow as well as acid secretion of the stomach. In comparison PGE1 administered at a dose rate of 4 mug/kg-h reduced significantly gastric mucosal blood-flow and gastric secretion. PGE1 at a dose rate of 8 mug/kg-h did not produce any significant changes in blood-flow and secretion. The results suggested that the changes of gastric secretion observed with PGE1 were the consequence of primary changes in the gastric mucosal blood-flow.

Animals↗

Intestinal mucosal uptake of iron and iron retention in idiopathic haemochromatosis as evidence for a mucosal abnormality.

The process of iron absorption has been studied in 23 patients with idiopathic haemochromatosis, in eight with iron-deficiency anaemia, and in 20 control subjects. The initial uptake of iron by the intestinal mucosa was estimated by administering (59)Fe-ferric citrate during a standard meal together with a non-absorbable marker, (51)Cr-chromic chloride. Body iron absorption (iron retained at 14 days) was measured by whole body counting with discriminant analysis to separate the two isotopes. Thus, the fraction of the initial mucosal uptake finally retained in the body was calculated (the mucosal transport index of iron). In control subjects the mean values for mucosal uptake of iron and body iron absorption were 12.0 - SD 4.9% and 3.6 - SD 2.4%, with a mean mucosal transport index of 0.31 - SD 0.21. Mucosal iron uptake and body absorption were both considerably increased in the patients with iron-deficiency anaemia (33.5 - 15.6 and 29.8 - 17.0% respectively) and in the eight patients with idiopathic haemochromatosis treated by venesection therapy until the excess iron stores were removed (27.2 - 12.0 and 26.6 - 14.6% respectively). The mucosal transport index in all these subjects approached 1.0. Eight patients with haemochromatosis were studied before venesection therapy. The mucosal uptake of iron was within the normal range in all (mean 14.0 - 2.8%) but body iron absorption was increased in five (mean 9.1 - 4.8%). The mean mucosal transport index of iron was significantly increased in this group (0.62 - 0.28; p < 0.01). The findings suggest that the increased iron absorption in subjects with idiopathic haemochromatosis results from an abnormality of the intestinal mucosa and not from altered intraluminal factors. However, whether the aberrant mucosal cell function is a primary defect in the cell or an acquired change, dependent on humoral or corporeal factors, is unknown.

Adult↗

The importance of local mucosal HIV-specific CD8(+) cytotoxic T lymphocytes for resistance to mucosal viral transmission in mice and enhancement of resistance by local administration of IL-12.

Although crucial to mucosal vaccine development, the mechanisms of defense against mucosal viral infection are still poorly understood. Protection, cytotoxic T lymphocytes (CTL), and neutralizing antibodies have all been observed, but cause and effect have been difficult to determine. The ability of CTL in the mucosa to mediate protection against mucosal viral transmission has never been proven. Here, we use an HIV peptide immunogen and an HIV-1 gp160-expressing recombinant vaccinia viral intrarectal murine challenge system, in which neutralizing antibodies do not play a role, to demonstrate for the first time that long-lasting immune resistance to mucosal viral transmission can be accomplished by CD8(+) CTL that must be present in the mucosal site of exposure. The resistance is ablated by depleting CD8(+) cells in vivo and requires CTL in the mucosa, whereas systemic (splenic) CTL are shown to be unable to protect against mucosal challenge. Furthermore, the resistance as well as the CTL response can be increased by local mucosal delivery of IL-12 with the vaccine. These results imply that induction of local mucosal CTL may be critical for success of a vaccine against viruses transmitted through a mucosal route, such as HIV.

Animals↗

Mucosal vaccines: non toxic derivatives of LT and CT as mucosal adjuvants.

Most vaccines are still delivered by injection. Mucosal vaccination would increase compliance and decrease the risk of spread of infectious diseases due to contaminated syringes. However, most vaccines are unable to induce immune responses when administered mucosally, and require the use of strong adjuvant on effective delivery systems. Cholera toxin (CT) and Escherichia coli enterotoxin (LT) are powerful mucosal adjuvants when co-administered with soluble antigens. However, their use in humans is hampered by their extremely high toxicity. During the past few years, site-directed mutagenesis has permitted the generation of LT and CT mutants fully non toxic or with dramatically reduced toxicity, which still retain their strong adjuvanticity at the mucosal level. Among these mutants, are LTK63 (serine-to-lysine substitution at position 63 in the A subunit) and LTR72 (alanine-to-arginine substitution at position 72 in the A subunit). The first is fully non toxic, whereas the latter retains some residual enzymatic activity. Both of them are extremely active as mucosal adjuvants, being able to induce very high titers of antibodies specific for the antigen with which they are co-administered. Both mutants have now been tested as mucosal adjuvants in different animal species using a wide variety of antigens. Interestingly, mucosal delivery (nasal or oral) of antigens together with LTK63 or LTR72 mutants also conferred protection against challenge in appropriate animal models (e.g. tetanus, Helicobacter pylori, pertussis, pneumococci, influenza, etc). In conclusion, these LTK63 and LTR72 mutants are safe adjuvants to enhance the immunogenicity of vaccines at the mucosal level, and will be tested soon in humans.

Adjuvants, Immunologic↗

Mucosal immunization with a DNA vaccine induces immune responses against HIV-1 at a mucosal site.

Mucosal immunity is the first defense system in protection against mucosal infection by sexually transmitted diseases and subsequent systemic dissemination of infection. Development of vaccines which can induce protective mucosal immunity would have great promise for preventing sexually transmitted diseases including AIDS. DNA vaccines have recently shown certain advantages over other types of vaccines in safety and elicitation of specific immune responses. We have hypothesized that direct delivery of a DNA plasmid coding the HIV-1 envelope (pcMN160) via mucosal routes will stimulate mucosal immunity against HIV-1. The expression of DNA plasmid inoculated intravaginally was detected in various tissues. Intravaginal inoculation of pcMN160 elicits production of vaginal immunoglobulins which specifically bind to the HIV-1 envelope and neutralize HIV-1 infectivity in vitro. These results indicate the feasibility of inducing mucosal immunity following mucosal inoculation of DNA vaccines. When coupled with systemic inoculation of appropriate DNA constructs, effective mucosal and systemic immunity may be generated.

AIDS Vaccines↗

Both mucosal and systemic routes of immunization with the live, attenuated NYVAC/simian immunodeficiency virus SIV(gpe) recombinant vaccine result in gag-specific CD8(+) T-cell responses in mucosal tissues of macaques.

As most human immunodeficiency virus (HIV) infection occurs via mucosal surfaces, an important goal of vaccination may be the induction of virus-specific immune responses at mucosal sites to contain viral infection early on. Here we designed a study in macaques carrying the major histocompatibility complex class I Mamu-A(*)01 molecule to assess the capacity of the highly attenuated poxvirus NYVAC/simian immunodeficiency virus (SIV) SIV(gpe) vaccine candidate administered by the intranasal, intramuscular, or intrarectal route to induce mucosal immunity. All macaques, including one naive macaque, were exposed to SIV(mac251) by the intrarectal route and sacrificed 48 h after infection. The kinetics of immune response at various time points following immunization with NYVAC/SIV(gpe) and the anamnestic response to SIV(mac251) at 48 h after challenge were assessed in blood, in serial rectal and vaginal biopsy samples, and in tissues at euthanasia with an SIV(mac) Gag-specific tetramer. In addition, at euthanasia, antigen-specific cells producing gamma interferon or tumor necrosis factor alpha from the jejunum lamina propria were quantified in all macaques. Surprisingly, antigen-specific CD8(+) T cells were found in the mucosal tissues of all immunized macaques regardless of whether the vaccine was administered by a mucosal route (intranasal or intrarectal) or systemically. In addition, following mucosal SIV(mac251) challenge, antigen-specific responses were mainly confined to mucosal tissues, again regardless of the route of immunization. We conclude that immunization with a live vector vaccine results in the appearance of CD8(+) T-cell responses at mucosal sites even when the vaccine is delivered by nonmucosal routes.

Administration, Intranasal↗

Induction of mucosal immunity by inactivated poliovirus vaccine is dependent on previous mucosal contact with live virus.

The inactivated poliovirus vaccine (IPV) is used for protection against poliomyelitis in The Netherlands. It is not clear, however, whether IPV vaccination can lead to priming of the mucosal immune system and the induction of IgA. It has been demonstrated that IPV vaccination is able to induce strong memory IgA responses in the serum of persons who have been naturally exposed to wild-type poliovirus. This has led to the hypothesis that IPV vaccination is able to induce poliovirus-specific IgA at mucosal sites in persons who have been previously primed with live poliovirus at mucosal sites. To test this hypothesis, the kinetics of the IgA response in serum and saliva after IPV vaccination were examined in persons previously vaccinated with oral poliovirus vaccine (OPV) or IPV. ELISA and enzyme-linked immunospot assays were used for the detection of poliovirus-specific IgA responses. In addition, B cell populations were separated on the basis of the expression of mucosal (alpha4beta7 integrin) and peripheral homing receptors (L-selectin). Parenteral IPV vaccination was able to boost systemic and mucosal IgA responses in previously OPV-vaccinated persons only. None of the previously vaccinated IPV recipients responded with the production of IgA in saliva. In agreement with this finding, a large percentage of the poliovirus-specific IgA-producing lymphocytes detected in previous OPV recipients expressed the alpha4beta7 integrin. It is concluded that IPV vaccination alone is insufficient to induce a mucosal IgA response against poliovirus. In mucosally (OPV-) primed individuals, however, booster vaccination with IPV leads to a strong mucosal IgA response.

Adult↗

Gastric mucosal blood flow in ethanol-induced mucosal damage in the rat.

Gastric mucosal blood flow in ethanol-induced mucosal damage was studied in urethane-anaesthetic rats by reference to 14C-aminopyrine clearance in the gastric mucosa. Irrigation of the stomach with 30% ethanol in acid saline (100 mM HCl plus 50 mM NaCl) for 40 min broke the gastric mucosal barrier, as indicated by an increased outflow of Na+ and K+ ions and back-diffusion of H+ ions. Gastric mucosal blood flow also increased about 2-fold decreasing after cessation of ethanol irrigation along with the net ion fluxes. The increase in gastric mucosal blood flow occasioned by 10, 20 and 30% ethanol in acid saline was directly proportional to the net fluxes of H+, Na+ and K+ ions. When the stomach was irrigated with 30% ethanol in a less acid medium (10 mM HCl, 90 mM choline chloride plus 50 mM NaCl) there was still a significant increase in the outflow of Na+ and K+ ions, but only a slight-back-diffusion of H+ ions. During this low rate of acid back-diffusion 30% ethanol reduced gastric mucosal blood flow by about 50%. The results suggest that ethanol-induced mucosal damage in the rat is associated with an increase in gastric mucosal blood flow only if combined with back-diffusion of H+ ions.

Animals↗