Modification of viral myocarditis in mice by interleukin-6

Inflammatory cytokines play a key role in the myocardial injury produced by viral myocarditis. Although interleukin-6 (IL-6) reportedly possesses antiviral properties, its effect in viral myocarditis is unclear. To investigate the role of IL-6 in viral myocarditis induced by encephalomyocarditis virus (EMCV) in mice, we evaluated (1) the survival rate following IL-6 administration, (2) the viral titer in the heart, (3) viral replication in the heart by in situ hybridization, (4) histopathological changes using immunohistochemical staining, (5) neutralizing antibody against EMCV, (6) circulating interferon and tumor necrosis factor-alpha (TNF-alpha), (7) viral suppression in vitro by IL-6, and (8) natural killer (NK)-cell activity. Eight-week-old C3H/HeJ mice were injected intraperitoneally with EMCV (day 0) and were also injected subcutaneously twice daily for 4 consecutive days with 10 micrograms/0.1 mL of human IL-6 on day -4 (group A), day 0 (group B), or day +4 (group D) for 4 days. As a control, 0.1 mL PBS instead of IL-6 was injected on day 0 for 4 days (group C). Certain mice were killed on day 4. The myocardial virus titers, viral replication in situ, and NK-cell activity in the spleen were determined. Decreased viral titer and viral replication in the heart reduced the titer of circulating TNF-alpha, and lower NK-cell activity was observed in group B versus group C (control group). The titer of neutralizing antibodies against EMCV was significantly (P < .05) increased in group B compared with group C. The remaining mice were killed on days 10 and 30 after infection. The ratio of heart weight (HW) to body weight (BW) and myocardial injury in group B were reduced versus group C on days 10 and 30. The HW of group B on day 30 did not differ from the normal control group. The ratio of splenic weight to BW and the ratio of thymic weight to BW of group B increased on day 10, with expanded follicles observed in the spleen and enlargement of the medulla observed in the thymus. Immunohistochemical study revealed an increased percentage of macrophages in the heart and spleen of group B. In summary, IL-6 reduces myocardial damage in mice with viral myocarditis. Modification of immune responses together with reduction in viral replication appears to be the mechanism of the IL-6 effect. Although IL-6 is likely important in the process of viral antigen presentation, early activation of immune responses and attenuation of viral replication appear most significant, as reflected in the limited time window during which IL-6 is effective in myocarditis.

Bradykinin increases intracellular free Ca2+ concentration and promotes insulin secretion in the clonal beta-cell line, HIT-T15

We have examined the effects of bradykinin (BK) on both the intracellular free calcium concentration ([Ca2+]i) and insulin secretion in the hamster beta-cell line, HIT-T15 cells. BK evoked a rise in [Ca2+]i in a dose-dependent manner. This response was suppressed by neomycin, suggesting that BK mobilizes Ca2+ from intracellular store via promotion of the phosphatidyl inositol turnover. Furthermore, BK also evoked insulin secretion. Both the BK-evoked rise in [Ca2+]i and insulin secretion were suppressed by the BK2 receptor antagonist, but not by the BK1 receptor antagonist. These results indicate that BK increases [Ca2+]i via BK2 receptor, thereby promoting insulin secretion in HIT-T15 cells.

Rush immunotherapy with house dust extract in patients with mild extrinsic asthma

Rush immunotherapy (RIT) with house dust extract was given to 15 patients with mild extrinsic or mixed asthma. Every patient was strongly positive for IgE on the radioimmunosorbent test and sensitive to house dust extract on the scratch skin test. Nine patients were positive on the bronchial provocation test to house dust extract and 6 could not be examined. All patients did not drop out and got to house dust extract solution 10(-1) within 1 week. The symptom-medication scores decreased significantly after RIT. During RIT 1 patient developed a mild asthmatic attack and 3 patients developed generalized skin reaction. Eight weeks later, the threshold for house dust-provoked bronchoconstriction increased in 9 patients, but did not in 3 patients. The blood eosinophil count and blood histamine level significantly decreased. We conclude that RIT is able to raise antigen concentrations for a short periods and effective but not risky for mild asthma.

Computer use in schools for the blind in Japan

In a school for the blind, computer use and feelings toward computers by 34 visually impaired students receiving secondary education and by their 42 teachers were investigated with a questionnaire. Most subjects used computers effectively, but some students who had low vision did not wish to use them to avoid strain on their eyes. The computers allowed use of Kanji (Chinese characters) by the blind students, providing a new tool in their learning of Kanji. In classes, it is necessary to maintain and customize the computers continuously.

[Drug-resistance patterns and biological properties of MRSA isolated from different geographical areas of Japan]

One hundred isolates of methicillin-resistant Staphylococcus aureus (MRSA) collected from hospitals located in different geographical areas of Japan were used in the present study. The susceptibilities of the strains to gentamicin (GM), erythromycin (EM), tetracycline (TC) and ofloxacin (OFLX) were determined and classified into twelve groups according to their differences in the patterns of the resistance to the four drugs. Of the 100 strains tested, 75 belonging to the main four groups were investigated for the relationships between their patterns of the drug-resistance and biological properties such as coagulase, enterotoxin and phage types, TSST-1 and beta-lactamase producibilities, and percentages of the strains carrying plasmids of large size (> or = 20,000 bp). The main four patterns of drug resistance of the 75 strains were as follows: the first group (33 strains resistant to GM, EM, TC and OFLX), the second group (15 strains resistant to EM, TC and OFLX), the third group (11 strains resistant to GM, EM and OFLX) and the fourth group (16 strains resistant to EM and OFLX) and the remaining 25 strains were divided into further groups. A considerable number of the strains in the third group differed markedly in some biological properties from those in the other groups; coagulase typing (III type-50%: the other groups-II type), enterotoxin typing (64%-non-production: the other groups-C type), TSST-1 producibility (36%-production: the other groups-76 to 88%-production) and phage typing (55%-non-typable: the other groups-80 to 97%-non-typable). In beta-lactamase and plasmids of large size, the first group consisted of the strains with beta-lactamase producibility at the ratio of 50:50, but the other groups consisted of most of the strains with the beta-lactamase producibility. Most of the strains belonging to the second and fourth groups carried large size of plasmids, but 36 and 46% of those belonging to the first and third groups did not carry them. On the other hand, our results of the susceptibility test for the 100 strains showed that a considerable number of strains were susceptible to GM (35%) and TC (42%) at therapeutically significant concentrations.

Interleukin-6 secreted from human myxoma reduces murine viral myocarditis

The effect of interleukin-6 (IL-6) secreted by a human atrial myxoma in vitro was investigated in C3H female mice with acute viral myocarditis. A culture medium containing IL-6 (100 ng/ml) and IL-8 (250 ng/ml), was prepared; viral myocarditis was induced by exposure to the encephalomyocarditis virus. Mice were assigned to four groups: 1) intraperitoneal (i.p.) injection of supernatant with IL-6 and IL-8 (0.2 ml/mice) given simultaneously with virus, 500 pfu for 4 days (Group 1); 2) i.p. injection of supernatant with IL-6 starting on Day 4 for 4 days in the same manner (Group 2); 3) i.p. injection of culture medium simultaneously with the virus (Group 3); and 4) i.p. injection of PBS in the same manner (Group 4). Uninfected control mice were administered medium only (Group 5) or supernatant with IL-6 and IL-8 (Group 6) for 4 days without virus. The survival rate on Day 14 in Group 1 was 90% significantly (p < 0.01) prolonged. The ratio of heart weight-to-day weight in the Group 1 was significantly (p < 0.01) lower. Histopathological examination revealed that cardiac necrosis and cellular infiltration in Group 1 was reduced compared with Group 3. Moreover, the radio of spleen weight/body weight in Group 1 was significantly (p < 0.01) higher than that of Group 3 and of Group 4. To confirm the effect of IL-6 or IL-8, mice were treated with recombinant IL-6 to IL-8 simultaneously with virus for 4 days. IL-6 treated mice survived significantly compared with IL-8 treated mice and untreated mice. The viral titer on day 4 of IL-6 treated mice was significantly lower than IL-8 treated or untreated mice. Thus, IL-6 derived from human myxoma improved the survival of murime viral myocarditis and reduced myocardial necrosis when the myxoma-derived IL-6 was administered simultaneously with the virus, due to eliciting cellular immunity in the spleen.

Effects of bradykinin on the intracellular calcium concentration of pancreatic acinar AR42J cells

We examined the effects of bradykinin (BK) on the intracellular free calcium concentration ([Ca2+]i) in rat pancreatic acinar AR42J cells. BK induced a dose-dependent rise in [Ca+2]i in AR42J cells between the concentrations of 10(-12)M and 10(-7)M. The BK-evoked response was not affected by the presence of Co2+ or the absence of extracellular calcium. This response was suppressed by neomycin or the B2 antagonist, but not by the B1 antagonist. The response was also attenuated by treatment with dexamethasone. These results suggest that BK increases [Ca2+]i through the B2 receptors by promoting the phosphatidyl inositol turn-over and that, in the process of azaserine-induced undifferentiation, the pancreatic acinar cells strongly express the BK receptors.

Calcium as a second messenger of the action of transforming growth factor-beta on insulin secretion

In MIN6 insulinoma cells, transforming growth factor-beta (TGF-beta) induced the oscillatory elevation of the cytoplasmic free calcium concentration, [Ca2+]c, in the presence of 5.5 mM glucose. The increase in [Ca2+]c induced by TGF-beta was totally dependent on calcium entry and attenuated by nifedipine or nickel chloride. In contrast, carbachol elevated [Ca2+]c in the presence of nickel chloride. When the plasma membrane was hyperpolarized by diazoxide, TGF-beta did not raise [Ca2+]c, whereas both carbachol and depolarizing concentration of potassium elevated [Ca2+]c under the same conditions. TGF-beta did not affect either the cellular cyclic AMP or inositol trisphosphate levels. In the presence of 5.5 mM glucose, TGF-beta induced a 3-fold increase in insulin secretion and the effect of TGF-beta was blocked by either nifedipine or nickel chloride. TGF-beta did not stimulate insulin secretion in the presence of 100 microM diazoxide, whereas both carbachol and 40 mM potassium chloride significantly increased insulin secretion. These results suggest that TGF-beta induces the oscillatory elevation of [Ca2+]c in MIN6 cells by stimulating calcium entry via voltage-dependent calcium channels. Calcium is an intracellular messenger of the action of TGF-beta on insulin secretion.

Immunohistochemical localization of cathepsins D and E in human gastric cancer: a possible correlation with local invasive and metastatic activities of carcinoma cells

The immunohistochemical localization of cathepsins D and E in 44 cases of human gastric carcinoma, using antibodies specific for each enzyme, were investigated. Cathepsin D- and E- positive carcinoma cells were present in all samples. However, the staining intensity varied from cell to cell in the same carcinoma tissue as well as among samples. The most intense immunostaining of both cathepsins was often found in the cells, which were present at the advancing margin of the carcinoma tissues. The incidence of this peculiar localization of intensely stained carcinoma cells significantly correlated with the progression of the carcinoma tissue (D, P < .05; E, P < .01) and with occurrence of the lymph node metastasis (D and E, P < .05). There was no statistical significance between this localization and the histological type (differentiation) of the carcinoma tissues. Cathepsin-positive inflammatory cells infiltrated in and around the carcinoma tissue, and intensely stained inflammatory cells were often located in the stroma at the border of the carcinoma tissue. However, no statistical correlation was noted between the localization of cathepsin-positive inflammatory cells at the border and the stage of progression or the incidence of metastasis. These results indicated that cathepsins D and E in the carcinoma cells located at the advancing margin play an important role in the invasion and subsequent metastasis of human gastric carcinoma. Meanwhile, cathepsin-positive inflammatory cells seem to be less responsible for the biological behavior of carcinoma cells than those in the carcinoma cells themselves.

Myocardial sympathetic dysinnervation in doxorubicin cardiomyopathy

Single photon emission computed tomography (SPECT) using I-123 metaiodobenzylguanidine (MIBG) was evaluated for the detection of doxorubicin (DXR) cardiomyopathy in seven patients with malignant lymphoma receiving DXR doses ranging from 70 to 530 mg (DXR group), and 20 normal subjects without hypertension, diabetes mellitus or electrocardiographic abnormalities (control group). The ratio of the heart to mediastinal counts (H/M) and the washout rate (WR) in MIBG SPECT images were compared between the two groups. Correlation of total doses of DXR with H/M and the relationship of H/M to WR were investigated. The H/M of the DXR group was lower than that of the control group (3.00 +/- 0.97 vs 4.90 +/- 1.08, p < 0.001). The WR of the DXR group was higher than that of the control group (30.9 +/- 10.5% vs 16.5 +/- 9.1%, p < 0.001). Total DXR doses were inversely correlated with H/M (r = -0.86), H/M correlated inversely with the WR (r = -0.83) only in the DXR group. Pathological findings of one patient, who died of DXR cardiomyopathy, showed atrophic and fibrotic nerve fibers in the apical inferior segment of the left ventricle where MIBG uptake was reduced markedly. DXR cardiomyopathy can be detected with MIBG SPECT as cardiac sympathetic nervous dysinnervation. The pathological findings correspond to the MIBG SPECT findings.

[Development of multi-drug resistant mutants of clinical isolates of Pseudomonas aeruginosa after exposure to fluoroquinolone]

Eight multi-drug resistant mutants (4.94%) were found in 162 clinical isolates of P. aeruginosa after exposure to norfloxacin at different concentrations (1/4, 1/2, 1, 2 and 4 MICs) and were investigated for the mechanisms of drug resistance. All the mutants were eight-times more resistant to norfloxacin than the respective parents, and showed the cross-resistance to the other fluoroquinolones. However, these mutants differed in the drug-resistant patterns; the 94-74 mutant was resistant to carbenicillin, ceftazidime and chloramphenicol, TA-15 mutant was resistant to imipenem, and the 93-183 was resistant to carbenicillin, ceftazidime and gentamicin. TA-16 mutant only showed a marked decrease in the bacterial uptake of norfloxacin. Profiles of the outer membrane proteins of the mutants were analyzed by SDS-PAGE method. The six mutants, except for TA-52 and 93-183 mutants, increased the intensity of bands in the 46 KD region. Three mutants (TA-15, TA-16 and 93-183) decreased the intensity of 44 KD (OMPE) and also the former two decreased the intensity of 22 KD (OMP G). The gryA mutations associated with fluoroquinolone-resistance were investigated for the eight mutants, and the 93-183 mutant showed to have the gyrA mutation caused by the alteration in the amino acid sequence of gyrA; Thr-83 (ACC) to Ile (ATC). The result of the present study indicate that multi-drug resistance of clinical isolates of P. aeruginosa develops through different types of mechanisms, and is not easily explained fully by the present results, and suggest that many factors attributed to the development of the resistances in those mutants remains to be clarified.

IgE and IgG4 antibodies from patients with mite allergy recognize different epitopes of Dermatophagoides pteronyssinus group II antigen (Der p2)

BACKGROUND

Der p 2, composed of 129 amino acids, is one of the major allergens of Dermatophagoides pteronyssinus. Several groups reported epitope mapping of IgE antibody but not of IgG or IgG subclass antibodies in Der p 2.

OBJECTIVE

The purpose of this study was to compare the epitopes recognized by Der p 2-specific IgE antibodies with those recognized by IgG4 antibodies.

METHODS

Recombinant fusion proteins containing a full-length peptide or overlapping five fragments of Der p 2 were prepared and analyzed for their reactivity with IgE and IgG subclass antibodies in sera from patients with mite allergy by means of Western blot procedure.

RESULTS

IgE antibodies in 12 of 13 sera tested bound to full-length Der p 2 (1-129). In 11 of these 12 sera, IgE antibodies bound to one or more of fragments 41-80, 64-105, or 81-129 but not to those of 1-40 or 20-63. Of the 11 sera in which the IgE antibodies to the fragments were detected, only four contained detectable levels of IgG4 antibodies reactive to the fragments. The binding spectra of the IgG4 antibodies against the fragments were rather wide and differed from those of IgE antibodies.

CONCLUSION

Results revealed that there are differences in epitope recognition between IgE and IgG4 antibodies; IgE antibodies recognize restricted parts of Der p 2 antigen compared with IgG4.

Semotiadil improves survival of rats with monocrotaline-induced pulmonary hypertension: comparison with diltiazem

We compared the effects of semotiadil, a novel Ca2+ channel blocker, with those of diltiazem on survival and regression of right ventricular hypertrophy and media thickening of pulmonary arteries in a rat model of pulmonary hypertension. Pulmonary hypertension was induced by a single injection of monocrotaline (80 mg/kg). Four weeks later, after pulmonary hypertension was confirmed, oral administration of semotiadil (10, 30, or 100 mg/kg/day) or diltiazem (100 or 300 mg/kg/day) was initiated. The rats were observed for 3 weeks. Survival was significantly longer in the group that received semotiadil 100 mg/kg/day than in the groups treated with diltiazem 100 or 300 mg/kg/day. Media thickness and smooth muscle area in pulmonary arteries were significantly less in rats treated with semotiadil 100 mg/kg/day than in animals treated with diltiazem 100 mg/kg/day. The right ventricle to left ventricle mass ratio, right ventricular wall thickness, and right ventricular myocardial fiber diameter were equal in these two groups. Semotiadil 100 mg/kg/day improved the survival of rats, which responded with a significant regression of right ventricular hypertrophy and media thickening of pulmonary arteries in comparison with rats treated with diltiazem 100 or 300 mg/kg/day.

Differences in titres of IgE, IgG4 and other IgG subclass anti-Der p 2 antibodies in allergic and non-allergic patients measured with recombinant allergen

BACKGROUND

The mite allergens are recognized as major causes of allergic disease such as bronchial asthma, allergic rhinitis and atopic dermatitis. The functions of allergen-specific IgG subclass antibodies are not defined.

OBJECTIVE

In order to clarify the relationship between IgE and IgG subclasses, we examined serum levels of the Dermatophagoides pteronyssinus group 2 (Der p 2)-specific antibodies of IgE, IgG total and IgG subclasses in children with mite allergy.

METHODS

We prepared a recombinant Der p 2 fusion protein and examined serum levels of Der p 2 antigen-specific antibodies by enzyme-linked immunosorbent assay (ELISA) systems developed in our laboratory using a recombinant Der p 2 as target antigen. Sera from 240 children with mite allergy and 25 controls were measured.

RESULTS

The serum levels of specific IgE and, to lesser degree, IgG4 were higher in allergic children than non-allergic controls, while in the levels of the other IgG subclasses there was no difference between the two groups. There was no correlation between levels of specific IgE and IgG4 or in those between specific IgG4 and other IgG subclasses.

CONCLUSION

Results indicate that the induction of Der p 2-specific IgG4 in allergic diseases is independent to IgE as well as other IgG subclasses.

Amlodipine inhibits the development of right ventricular hypertrophy and medial thickening of pulmonary arteries in a rat model of pulmonary hypertension

This study was designed to evaluate the effects of amlodipine, a new calcium channel blocker, on the development of right ventricular hypertrophy and thickening of the media of the pulmonary arteries in a rat model of pulmonary hypertension. Pulmonary hypertension was induced in rats by administering a single injection of monocrotaline, 80 mg/kg. The oral administration of amlodipine, 3, 10, or 30 mg/kg/day, was initiated 24 hours later (day 1). On day 28 of therapy, we determined the right ventricular systolic pressure (RVSP), the mass ratio of the right ventricle (RV) to the left ventricle, the thickness of the wall of the RV, the diameter of myocardial fibers in the RV, the percent thickness of the media of the pulmonary artery, and the percent area of smooth muscle in the pulmonary arteries. The magnitude of all parameters was significantly less in the rats administered amlodipine, 30 mg/kg/day, vs. the control group given monocrotaline alone. RVSP, the percent medial thickness, and the percent smooth muscle area, were significantly lower in rats administered a dose of amlodipine, 30 mg/kg/day vs. 10 mg/kg/day. The oral administration of amlodipine, 30 mg/kg/day, inhibited the development of RV hypertrophy and medial thickening of the pulmonary arteries in rats exposed to monocrotaline significantly more effectively vs. the untreated control exposed only to monocrotaline.

Biological behavior of human dental pulp cells in response to carious stimuli analyzed by PCNA immunostaining and AgNOR staining

The change in proliferative and metabolic activities of human dental pulp cells responding to carious stimuli was studied by means of immunohistochemical staining for proliferating cell nuclear antigen (PCNA) and silver-binding nucleolar organizer region (AgNOR) staining. We classified the pulp tissues into five groups according to the progression of dental caries, ranging from grade 0 (the pulp of noncarious teeth) to grade 4 (the pulp of perforated carious teeth). PCNA-positive pulp cells were detected only in advanced dental caries (grades 3 and 4), and the difference in immuno-positive rate was significant between the two grades (p <0.001). However, the mean number of AgNORs per nucleus increased even in the early phase of dental caries, significant differences being detected between grades 1 and 2 (p<0.005), 2 and 3 (p<0.005), and 3 and 4 (p<0.001). Our data suggested that the metabolic activity of dental pulp cells was enhanced in the early phase of dental caries. However, proliferation of pulp cells occurred later in small degrees during fully developed caries such as grades 3 and 4. The slow and weak response in cellular proliferation might contribute to the usual fragility of the pulp to various assaults including caries or pulpitis.

Cell biology of early events in the plant resistance response to infection by pathogenic fungi

In addition to passive (or constitutive) defence mechanisms, plants have evolved a range of active (or inducible) responses that occur rapidly on infection with an incompatible (avirulent) pathogen and that are thought to play a major role in the expression of resistance. These defence reactions are only induced if the plant possesses the ability to recognize and respond to the pathogen. Signal reception by the host must initiate a cascade of events that lead to the expression of resistance. Some resistance responses, such as callose deposition, do not require the expression of new genes. Many responses, for example the synthesis and secretion of toxic compounds or molecules that enhance the strength of physical barriers, result from changes in the pattern of gene transcription. Other defence phenomena include hypersensitive cell collapse, intercellular signalling, and the induction of defence gene transcripts in surrounding cells. Changes in cell biochemistry and physiology are accompanied by characteristic structural modifications in the infected cells, such as the redeployment of selected organelles and dramatic modifications of the host cell wall. Recent evidence indicates that microtubules and microfilaments of the plant cytoskeleton facilitate the rapid localization of these and other plant defence responses to the region of infection. Key words: plant resistance, plant cytoskeleton, microtubules, microfilaments, fungal pathogens, polarity of defence response.

Hyperpnoea during and immediately after exercise in man: evidence of motor cortical involvement

1. The neurophysiological basis for the increase in breathing associated with exercise remains obscure. The present study uses positron emission tomography (PET) to measure relative regional cerebral blood flow (rCBF) in order to identify sites of increased neuronal activation during and immediately following exercise. 2. Male volunteers underwent H2(15)O PET scanning during two complementary studies. Firstly, six subjects performed right leg exercise, adequate to increase oxygen uptake 2.5-fold. Secondly, five different subjects were scanned immediately following bicycle exercise (adequate to increase oxygen uptake 5-fold) while breathing was still increased. In each study, as a control, scanning was also performed during matched passive isocapnic positive pressure ventilation; additionally, in the first study, passive right leg movement was performed. 3. Increases in relative rCBF were obtained in each individual and co-registered with their magnetic resonance image of the brain defining individual gyral morphology. 4. During exercise, individual and group analysis revealed significant relative rCBF increases in the left and right superomedial primary motor cortex (the motor cortical 'leg' areas) and also in the left and right superolateral primary motor cortex in areas previously shown to be associated with volitional breathing. After exercise, there was no significant increase in relative rCBF in the superomedial areas but such increases were still present bilaterally in the superolateral areas which had been activated during the exercise. Other relative rCBF increases were also found, both during and after exercise, in cortical and subcortical areas known to be involved in motor control. 5. The results from PET scans during and after exercise, taken together, provide evidence for motor cortical involvement in the exercise-related hyperpnoea in man.

L-type calcium channel blockers modulate the microvascular hyperpermeability induced by platelet-activating factor in vivo

PURPOSE

Platelet-activating factor (PAF) is a potent phospholipid mediator of the microvascular dysfunction associated with ischemia-reperfusion injury. Because changes in cytosolic-free Ca2+ concentration are essential in PAF cellular signaling, we formulated the hypothesis that blockade of Ca2+ entry may inhibit the PAF-induced microvascular dysfunction.

METHODS

To investigate this hypothesis two L-type calcium channel blockers, verapamil and nifedipine, were applied to the hamster cheek pouch before the topical PAF challenge was undertaken. Permeability was assessed by measurement of the plasma clearance of fluorescein isothiocyanate dextran, 150,000 mol wt. The arteriolar diameter was measured simultaneously to evaluate the effects of L-type calcium channel blockers on PAF-induced vasoconstriction.

RESULTS

Baseline clearance was 498.7 +/- 225.0 nl/60 min/gm (mean +/- SE). PAF at 10(-8) mol/L (n = 5) increased clearance to 3753.8 +/- 572.8 nl/60 min/gm (p < 0.01). Pretreatment with verapamil (2 mg/kg; n = 5) significantly reduced the increase in permeability caused by 10(-8) mol/L PAF (1909.1 +/- 620.2 nl/60 min/gm; p < 0.05). Nifedipine (5-10(-6) mol/L; n = 5) also significantly attenuated the impact of 10(-8) mol/L PAF (2037.2 +/- 427.5 nl/60 min/gm; p < 0.05). Neither verapamil nor nifedipine affected PAF-induced vasoconstriction.

CONCLUSION

The significant inhibition of the increase in permeability by the L-type calcium channel blockers suggests that these compounds may be useful in the management of PAF-induced hyperpermeability.

Semotiadil inhibits the development of right ventricular hypertrophy and medial thickening of pulmonary arteries in a rat model of pulmonary hypertension

This study was designed to compare the effects of semotiadil, a novel calcium antagonist, with those of diltiazem on the development of right ventricular hypertrophy and medial thickening of pulmonary arteries in a rat model of pulmonary hypertension. Pulmonary hypertension was induced by a single injection of monocrotaline (80 mg/kg). Twenty-four hours later (day 1), oral administration of semotiadil (10, 30, or 100 mg/kg per day) or diltiazem (100 or 300 mg/kg per day) was initiated. The wall thickness of the right ventricle (RV), the RV myocardial fiber diameter, the percent medial pulmonary artery thickness, and the percent area of smooth muscle in pulmonary arteries were determined on day 28. The magnitude of all parameters was significantly less in the group of seven rats that received semotiadil at 100 mg/kg per day than in the group of seven rats treated with diltiazem at 300 mg/kg per day. Semotiadil at 100 mg/kg per day inhibits the development of RV hypertrophy and medial thickening of pulmonary arteries significantly more effectively than diltiazem at 300 mg/kg per day.

Transient bacteremia after tooth extraction with intravenous cefuroxime prophylaxis

Twenty-four blood samples obtained after tooth extraction with intravenous cefuroxime prophylaxis were cultured on Bactec NR16A and NR 17A (Becton Dickinson, Maryland, U. S. A.). MIC of identified microbes and the serum levels of cefuroxime were also measured. The overall incidence of bacteremia was 16.7% (four out of 24). Although nine strains were isolated, no streptococcal bacteremia occurred. The MICs of cefuroxime varied from 0.05 to 12.5 micrograms/ml, and serum levels ranged from 100 to 233 micrograms/ml, which were satisfactory concentrations for the microorganisms isolated. The results suggested that intravenous cefuroxime prophylaxis for tooth extraction reduced the incidence of bacteremia, as well as the isolation rate of streptococci, significantly.