Nitric oxide synthesis is decreased in periodontitis.

OBJECTIVES: In order to study the possible role of nitric oxide (NO) in the development of periodontitis, we measured the concentration of its stable metabolite nitrite (NO2-) in the saliva of patients with periodontitis and healthy subjects. MATERIALS AND METHODS: We have analysed salivary NO2- concentrations in 25 subjects with rapidly progressive periodontitis (RPP), 25 with adult periodontitis (AP) and in 25 periodontally-healthy persons. The concentrations of NO2- were determined by the Griess reaction in microtitration plates. Periodontal tissue destruction was determined by measuring the attachment level loss using standard methods. RESULTS: Subjects with periodontitis had significantly less NO2- in saliva than healthy subjects. Subjects with RPP had lower NO2- concentrations than those with AP Parotid gland saliva contained less NO2- than sublingual gland or total saliva. CONCLUSIONS: Local NO production is decreased in patients with periodontitis. This effect is more pronounced in those with severe types of disease.

Effects of smoking and Helicobacter pylori on prostaglandin concentrations in gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis.

The aim of this study was to determine the level of endogenous prostaglandin E2 (PGE2), prostaglandin F1 alpha (6-keto-PGF1 alpha) and thromboxane B2 (TXB2) in the gastric and duodenal mucosa of patients with duodenal ulcer and duodenitis. Besides, the investigation aimed at determining the effect of smoking and infection by Helicobater pylori on prostaglandin synthesis. The investigation comprised 62 patients with duodenal ulcer, 46 patients with duodenitis and 44 controls. The results of our investigation indicate that the decreased prostaglandin synthesis in gastric and duodenal mucosa determined in patients with duodenal ulcer may have a considerable role in development of duodenal ulcer. Furthermore, the harmful effects of smoking on the gastric and duodenal mucosa may be mediated by the decreased prostaglandin synthesis in the gastric and duodenal mucosa. However, Helicobacter pylori seems to affect the development of duodenal ulcer through other mechanisms.

Serum angiotensin-converting enzyme activity in patients with endemic nephropathy.

Serum angiotensin-converting enzyme was measured in 60 patients with endemic nephropathy and in 30 healthy individuals. According to the arterial blood pressure, the patients with endemic nephropathy were further divided into groups with arterial hypertension (n = 30) and without arterial hypertension (n = 30). The activity of angiotensin-converting enzyme was determined by a spectrophotometric method using hippuryl-l-histidyl-l-leucine as a substrate. The serum activity of angiotensin-converting enzyme was significantly increased in the patients with endemic nephropathy (28.51 +/- 1.64 U/l) as compared with healthy individuals (20.83 +/- 1.33 U/l). The level of the enzyme was further increased if the endemic nephropathy was accompanied by arterial hypertension (37.09 +/- 1.45 U/l). The possible mechanisms of the increase in the angiotensin-converting enzyme activity are discussed.

Arachidonic acid metabolites and sinonasal polyposis. I. Possible prognostic value.

PURPOSE: The etiology of sinonasal polyps is sometimes obscure. This study was undertaken to evaluate the potential role of arachidonic acid metabolites (AAm) on recurrent polyposis. MATERIALS AND METHODS: Tissue production of prostaglandin E2 (PGE2), 6-keto-prostaglandin F1-alpha (PGI2), thromboxane A2 (TxA2), and leukotriene C4 (LTC4) by nasal mucosa was determined by radioimmunoassay in 27 patients with sinonasal polyposis (SNp) and in 10 volunteers. RESULTS: The group of patients with SNp with the evidence of recurrences in postoperative period (Group 1) showed significantly lower PGE2 concentrations than group of patients with SNp recurrences (Group 2). The differences in concentrations of PGI2 in mentioned groups were insignificant. In comparison with other groups, a group of patients who underwent surgery several times for SNp (Group 4) had a higher mean TxA2 concentration. The LTC4 concentrations were the highest in groups of patients where SNp recurrences were observed. When the incidence of polyposis recurrences (within 18 months after surgery) was correlated with the level of LTC4 production at the time of surgery, the rate of recurrence was significantly higher in patients with increased LTC4 level than in those with normal LTC4 levels. CONCLUSIONS: LTC4 might have a prognostic value. The possible role of AAm in occurrence of SNp is apparent and suggests possible role for medical intervention.

Effect of cyclophosphamide on tumor cell sensitivity to the action of immunological effectors.

A single sublethal dose of cyclophosphamide (CY) given to mice with Ehrlich ascites carcinoma (EAC) kills tumor cells and inhibits tumor growth for the first five days after its administration. From day 7 on, treated tumor cells reassume their growth, but their transplantability in normal recipients is greatly reduced for further three weeks more. On the other hand, the transplantability of untreated (control) and CY-treated cells in T cell-deficient mice is similar. Experiments with criss-cross immunization and challenge have shown that CY-treated cells are equally, or even less, immunogenic than un-treated cells. On the other hand, CY-pretreated cells are several times more sensitive to immunological attack of passively transferred immune spleen cells. These data show that CY does not increase the tumor cell immunogenicity but only increases its sensitivity to immunological attack.

Ketoconazole inhibits acetaminophen-induced hepatotoxicity in mice.

OBJECTIVE: To investigate the effect of ketoconazole on acetaminophen (AAP)-induced hepatotoxicity in mice. MATERIALS AND METHODS: Mice were given AAP intragastrically (300 mg/kg) and treated with ketoconazole (100 mg/kg intraperitoneally) or saline either 30 min before or 2-3 h after AAP administration. Mortality was recorded for 48 h, during which all mice given saline either died or recovered fully. Serum alanine and aspartate transaminase levels were determined 24 h after administration of AAP. Prostaglandin E2, thromboxane A2 and leukotriene C4 production was determined 6 h after AAP administration in the supernatants from the short-term culture of liver fragments by radioimmunoassay. RESULTS: Ketoconazole significantly decreased mortality and transaminase levels when given to mice either 30 min before or 2 h after AAP. Liver fragments from mice with AAP hepatitis produced greater quantities of prostaglandin E2, thromboxane A2 and leukotriene C4 than fragments from normal liver. Pretreatment of mice with ketoconazole or its addition to liver fragments ex vivo further increased the production of prostaglandin E2 and reduced the production of thromboxane A2. The effect of ketoconazole on leukotriene C4 synthesis was different in vivo (synthesis stimulation) from in vitro (synthesis inhibition). CONCLUSION: The protective effect of ketoconazole in AAP hepatitis is most probably mediated by modulation of eicosanoid synthesis by liver cells.

Multiple choice question tests in physiology: a preliminary attempt to apply the minimum pass level.

At the mid-term test in Part I Physiology at the University of Zagreb the students (n = 280) were graded by our standard pass level (SPL) arbitrarily set at 54% correct answers (SPL = 0.54). The test consisted of 50 items of the one best answer type. Items were selected from the pool by one examiner to conform, by his judgement, to the predetermined SPL. Post hoc the minimum pass level (MPL) was assessed independently by eight examiners and an MPL value of 0.60 for the whole test was obtained. The original Nedelsky scale was used in assessment of MPL but for statistical analysis the data was expressed as log(1/MPL) to linearize the scale of measurements and to reduce the variances. The data showed a large difference between examiners in their assessment of MPL. Nevertheless, the average log(1/MPL) value of individual items showed a significant negative linear relationship with the item difficulty indices as calculated from student's answers, indicating that despite the large heterogenity in assessment the average item log(1/MPL) may be acceptable as a reasonable prediction of item difficulty. Finally, 'subtests' were formed from the whole test by grouping items according to their log(1/MPL) value. The passing rate at these subtests was found to be identical despite the fact that they considerably differed in their MPL values. Therefore, the MPL value seems to be useful in setting objective standards for the decision of pass or fail, even when the MPL was assessed in a very heterogenous way.

Acute upper respiratory tract infections and indications for tonsillectomy in children. I. Immunoglobulin synthesis in the palatine tonsil tissue.

Current viewpoints and practice concerning indications for tonsillectomy are presented. The annual specific risk for upper respiratory infection in children aged up to 15 is 1.1. The risk is higher in the youngest age group, in whom it rises to 1.8, decreasing with age and being lowest among children aged 12-15 years (0.5). The proportion of tonsillitis among acute upper respiratory tract infections is highest in the age group up to 3 years (36.9%); at the age of 4-5 years it is 37.1%, and is lowest among children aged 12-15 years (21.9%). The risk of tonsillitis caused by streptococci is highest among children aged up to 5 years. Statistical significance of differences in the synthesis of immunoglobulins (G, M, A and sA) and lysozymes in the palatine tonsil tissue of tonsillectomized children and healthy volunteers was tested by non-parametric tests for independent samples. Significant differences of the above mentioned syntheses were found in all entities studied. Any contribution to the documentation on the nature and cause of each tonsillitis in childhood is of great clinical value, because it is the only basis for rational consideration of indications for tonsillectomy.

Gonadectomy abrogates sex differences in the effectiveness of chemical carcinogenesis in mice.

Sham-gonadectomized and gonadectomized male and female mice were given methylcholanthrene s.c. to assess the influence of sex hormones on carcinogenesis. Gonadectomy decreased the concentration of the respective sex hormone and increased the concentration of the opposite sex hormone. The results showed that androgens enhanced the effectiveness of carcinogenesis, while estrogens had the opposite effect. Gonadectomy effectively abrogated the sex differences in tumor induction.

The effect of interleukin 1 alpha on acetaminophen-induced hepatotoxicity.

The protective effect of interleukin 1 alpha (IL-1 alpha) in mice with acetaminophen (AAP)-induced hepatitis was investigated. IL-1 alpha had a significant protective effect if given 2 or more hours (up to 24 hours) before AAP; it significantly reduced mortality of mice and decreased serum transaminase level. The maximal effect was obtained with the dose of 1000 U (166 ng/kg) IL-1 alpha. Pretreatment with IL-1 significantly increased the synthesis of prostaglandin E2 (PGE2) in samples of liver tissue from AAP-treated mice, but had no effect on the synthesis of leukotriene C4 (LTC4). Pretreatment with indomethacin (IMC) did not abrogate significantly the protective effect of IL-1. Thus, the hepatoprotective effect of IL-1 alpha can not be entirely explained by the stimulation of prostaglandin (PG) synthesis.

Effect of three biological response modifiers on chemical carcinogenesis in mice.

The modulation of chemical carcinogenesis by three biological response modifiers was assessed in a mouse model. CBA mice given 20-methylcholanthrene s.c. were treated with peptidoglycan monomer, azure B and indomethacin for one month, either from day 0 or 75 after methylcholanthrene injection to assess their effects on tumor incidence (on days 150 and 300), time of tumor appearance, time of death, and duration and dynamics of tumor growth. All three agents significantly influenced some of the parameters of tumor growth, except tumor incidence on day 300. Highly significant sex differences in tumor appearance and growth were observed. Tumors with late appearance grew faster in comparison to tumors with early appearance. The data presented indicate that the effectiveness of anti-cancer body defense mechanisms can be best defined by the time of tumor appearance.

The influence of cyclophosphamide on antitumor immunity in mice bearing late-stage tumors.

Spleen cells from mice bearing late-stage methylcholanthrene-induced tumor did not show any tumor activity when mixed with tumor cells in Winn's assay. Treatment of these mice with cyclophosphamide (CY) induced a tumor-inhibitory activity in spleen, occurring on day 7 after treatment, reaching its maximum on day 11 and disappearing by day 21. This antitumor activity could not be induced in control, tumor-free or T-deficient tumor-bearing mice. CY-induced tumor-inhibitory activity was immunologically specific, and mediated by Thy-1+, L3T4-, Ly-2+ cells. Contrary to spleen cells from untreated tumor-bearing mice, spleen cells from CY-treated tumor-bearing mice did not suppress the antitumor activity of immune spleen cells in Winn's assay. However, in contrast to immune spleen cells, CY-induced tumor-inhibitory cells did not manifest antitumor activity when transferred systemically (i.v.) into T-cell-deficient tumor-bearing mice. Even more, spleen cells from CY-pretreated mice, harvested 7-15 days after the drug administration, partially suppressed the antitumor activity of concomitantly transferred spleen cells from specifically immune mice. Nevertheless, CY-pretreated mice manifested concomitant immunity, i.e. these mice exhibited higher resistance to a second inoculum of the same tumor than did nontreated mice or even mice with excised primary tumor.

Lipid-bound sialic acid, prostaglandin E and histamine in head and neck cancer.

Blood concentration of lipid-bound sialic acid (LBSA), prostaglandin E (PGE) and histamine were determined in 37 patients with carcinoma of hypopharynx and larynx (supraglottic and glottic), in 12 non-cancer patients and in 10 healthy subjects. The concentration of LBSA was significantly increased in 94.4% cancer patients preoperatively and fell to somewhat lower levels within 1 month after tumour resection. In patients with complete tumour resection and no tumour recurrences within 2 years, it steadily decreased thereafter, reaching normal levels within 6-24 months after surgery, whereas in patients with tumour recurrences or incomplete tumour resection it rose again within 6 months after tumour resection. Similarly, the concentration of PGE was significantly increased in about two thirds of cancer patients (67.6%) preoperatively, dropped significantly within 1 month after tumour resection and rose again in patients with tumour recurrences. Preoperative histamine concentration was decreased in 24.3% of cancer patients and postoperatively it rose both in patients with or without tumour recurrences.

Prognostic significance of plasma prostaglandin E concentration in patients with head and neck cancer.

Plasma prostaglandin E (PGE) levels were determined by radioimmunoassay in 53 patients with various stages (II, III, and IV) of hypopharyngeal and laryngeal squamous cell carcinoma, in 12 non-cancer patients and in 10 healthy volunteers. The mean PGE concentration was somewhat higher in non-cancer patients (mean +/- SD = 34.6 +/- 5.37 pg/ml) than in healthy subjects (28.1 +/- 4.96 pg/ml). In spite of a high data variability, the mean preoperative PGE levels in cancer patients were proportional to the stage of the disease and higher than in non-cancer patients (41.2 +/- 19.7 pg/ml, 52.8 +/- 26.7 pg/ml and 82.0 +/- 34.9 pg/ml in stages II, III and IV respectively). The mean plasma PGE concentration significantly decreased for all tumour stages 15-30 days after surgical removal of the tumour, but rose again in some patients within 6-18 months after surgery. The incidence of tumour recurrences 6 and 18 months after surgery was significantly higher in patients with an increased preoperative PGE level (greater than 43.3 pg/ml) than in those patients with a PGE level within the normal range (less than 43.3 pg/ml). The mortality was also higher in the former group, but the difference did not reach the level of significance. Similarly, the mean preoperative and most postoperative concentrations of PGE were significantly higher in patients in whom tumour recurred within 18 months than in tumour-free patients.

Production of prostaglandin E by squamous carcinoma of the head and neck and adenocarcinoma of gastrointestinal tissue.

The production of prostaglandin E ex vivo was studied in samples of 31 squamous cell carcinomas of the head and neck (SCCHN) and 12 adenocarcinomas of gastrointestinal tract (ACGI). As a control, the PGE production was measured in 22 samples of noninvolved mucosa in patients with SCCHN and 12 samples of gastrointestinal mucosas. The mean PGE production by SCCHN was significantly higher than in normal mucosa. Furthermore, the PGE production by tumors which recurred or spread to regional lymph node within 18 months after surgery was higher than in tumors which did not recur within that interval. Also, production of PGE by noninvolved mucosa was significantly higher in patients in which tumor recurred after surgery than in patients which were tumor free. On the other hand, the mean production of PGE by ACGI was not different from that of normal mucosa. These data show that determination of PGE production might have prognostic significance in SCCHN.

Anti-tumoral and anti-inflammatory effects of biological stains.

The biological stains, methylene blue and its metabolite azure B, were evaluated as anti-tumor and anti-inflammatory agents. Azur B, administered in drinking water to tumor-bearing mice, inhibited the growth of transplanted tumors and the growth of primary tumors induced by methylcholanthrene. Inhibition of growth of primary tumors was observed only in female mice. Azure B also reduced the wet weight of carrageenin-induced granulomas in rats. Azure B, given intravenously to BCG-sensitized mice 15 minutes prior to challenge with lipopolysaccharide, decreased TNF production (to 10% of control values) and prevented death from endotoxic shock. Methylene blue decreased TNF production (to 50% of control values) but did not protect the animals from endotoxic shock. Our results suggest that some of the effects previously ascribed to methylene blue are probably mediated via its metabolite, i.e. azure B. Low toxicity and easy administration of the dyes explain their use in clinical settings.

[Histamine levels in the blood in patients with malignant tumors]. / Razina histamina u krvi kod bolesnika s malignim tumorom.

The concentration of histamine in blood was determined in 22 patients with solid malignant tumors, 16 hospitalized non-cancer patients and 9 healthy subjects. Patients with cancer (mainly carcinomas of the breast and gastrointestinal tract) were divided into two groups: patients with resected primary tumor without known metastases (group I) and patients with present primary tumor with or without metastases (group II). In comparison with the healthy subjects (histamine concentration 69.0 +/- 6.03 ng.ml-1), cancer patients in both groups had significantly decreased levels of histamine in blood. Also, the concentration of histamine in patients with present tumor (group II; 40.1 +/- 3.48 ng.ml-1) vas significantly lower than in patients with resected primary tumor (49.9 +/- 3.14 ng.ml-1). Furthermore, hospitalized non-cancer patients had lower, but not statistically significant, concentration of histamine (59.7 +/- 6.13 ng.ml-1) than healthy subjects. These findings, together with similar data of other authors, suggest that decreased level of histamine in blood might be a good nonspecific marker for onset and progression of solid malignant tumors.

The effectiveness of intravenously administered immune lymphoid cells against intraperitoneally growing tumor correlates with their homing in the recipients' lymphoid organs.

Intraperitoneally growing Ehrlich ascites tumor (EAT) was eradicated by both i.p. and i.v. injection of serum, and by i.p. injection of spleen cells from mice immune to EAT. However, the i.v. injected immune spleen cells were completely ineffective unless the recipients had been pretreated with cyclophosphamide. The analysis of immune response in mice cured by the combination of cyclophosphamide and cell transfer revealed that they developed a humoral-type immunity to EAT and that the transferred spleen cells did not penetrate into their abdominal cavity. The effect of cyclophosphamide correlated with the extent of seeding of the donor-type cells in the recipients' lymphoid organs. Inasmuch as homing in cyclophosphamide-pretreated mice surpassed that in normal mice three to four times, it appeared that the beneficial effect of cyclophosphamide was primarily founded on its enhancement of seeding of the transferred lymphoid cells, implying that homing of these cells is a prerequisite for their anti-tumor activity.