Fully enzymatic method for determining 1,5-anhydro-D-glucitol in serum

We have developed a fully enzymatic method to measure 1,5 anhydro-D-glucitol (1,5-AG) in serum through use of pyranose oxidase (PROD: EC 1.1.3.10), glucokinase (EC 2.7.1.2), and an ATP-regenerating system. In a previous report (Clin Chem 1989;35:2039-43) the glucose interfering with the measurement of 1,5-AG was removed with a minicolumn. In the method used here, glucokinase and an ATP-regenerating system efficiently convert glucose to the unreactive compound, glucose 6-phosphate, making the method selective for 1,5-AG. The hydrogen peroxide produced in the oxidation of 1,5-AG by PROD is detected with a standard enzymatic color-developing system. The within-run and day-to-day precision (CV) of this method was 0.52-1.29% and 1.17-4.48%, respectively. The correlation (r) between the results obtained with our proposed method (y) and those obtained with the mini-column method (x) was 0.998 (y = 1.007x + 0.493 mg/L; n = 100; Sy/x = 0.641 mg/L). This newly developed method allows quicker and easier measurement of serum 1,5-AG than previously described methods.

Diaphragmatic electrical activity during controlled and assisted mechanical ventilation in conscious human subjects

Breathing during mechanical ventilation was analyzed in 8 conscious healthy volunteers by application of intermittent positive pressure ventilation through a mouthpiece. In controlled mechanical ventilation (CMV), the respiratory rate and tidal volume were fixed at 110 and 120% of the subject's corresponding spontaneous breathing parameters. The diaphragmatic electromyogram (EMGdi) decreased significantly but become synchronous with the rhythm of the CMV. In assisted mechanical ventilation (AMV), the EMGdi response developed prior to and during the inspiratory phase of AMV. Application of an unexpected mechanical breath elicited the EMGdi. As the triggering sensitivity was decreased, the EMGdi prior to and during a mechanical breath was augmented, however, its rate of rise was unaffected. Our results suggest that the EMGdi during mechanical ventilation in conscious subjects is initiated by the respiratory center, however, this activity is modulated strongly by input from the pulmonary afferents and from the cerebral cortex.

Fully enzymatic method for determining 1,5-anhydro-D-glucitol in serum

We have developed a fully enzymatic method to measure 1,5 anhydro-D-glucitol (1,5-AG) in serum through use of pyranose oxidase (PROD: EC 1.1.3.10), glucokinase (EC 2.7.1.2), and an ATP-regenerating system. In a previous report (Clin Chem 1989;35:2039-43) the glucose interfering with the measurement of 1,5-AG was removed with a minicolumn. In the method used here, glucokinase and an ATP-regenerating system efficiently convert glucose to the unreactive compound, glucose 6-phosphate, making the method selective for 1,5-AG. The hydrogen peroxide produced in the oxidation of 1,5-AG by PROD is detected with a standard enzymatic color-developing system. The within-run and day-to-day precision (CV) of this method was 0.52-1.29% and 1.17-4.48%, respectively. The correlation (r) between the results obtained with our proposed method (y) and those obtained with the mini-column method (x) was 0.998 (y = 1.007x + 0.493 mg/L; n = 100; Sy/x = 0.641 mg/L). This newly developed method allows quicker and easier measurement of serum 1,5-AG than previously described methods.

[A trial of setting of the reference intervals of thrombin antithrombin III complex and fibrin.fibrinogen degradation products in pregnant women]

Activity of coagulation and fibrinolysis during pregnancy differed greatly from that during a nonpregnant period. We examined the reference intervals by mean +/- 2 standard deviations for thrombin antithrombin III complex (TAT), total FDP (T-FDP), FDP-E, D-dimer before and after delivery. The reference intervals obtained were as follows: TAT (micrograms/l): 1.0-4.8 for 1st trimester, 2.0-10.2 for 2nd trimester, 2.8-14.2 for 3rd trimester, 2.6-16.3 for full term pregnancy, 0-10.5 for post partum. T-FDP (micrograms/ml): 1.5-4.2 for 1st trimester, 1.8-5.6 for 2nd trimester, 1.9-8.5 for 3rd trimester, 2.9-9.7 for full term pregnancy, 2.4-9.0 for post partum. FDP-E(ng/ml): 26.4-98.0 for 1st trimester, 42.4-176.7 for 2nd trimester, 53.1-222.5 for 3rd trimester, 82.4-297.9 for full term pregnancy, 56.9-240.6 for post partum. D-dimer (micrograms/ml): 0.2-2.0 for 1st trimester, 0.6-3.8 for 2nd trimester, 0.6-4.3 for 3rd trimester, 0.7-6.8 for full term pregnancy, 0.6-5.7 for post partum. Further studies are needed to determine the borderline values to determine the clinical abnormality, with a comparison of the reference intervals with the pathologic laboratory data.

[Differential effects of morphine and non-steroidal anti-inflammatory drugs on somatic and visceral pain in rats]

We studied the differential effects of morphine and non-steroidal anti-inflammatory drug (NSAIDs) on behavioral responses to tail-flick (TF) and colorectal distension (CD) in rats. Animals were randomly divided into three groups; morphine groups (4 mg.kg-1), flurbiprofen axetil groups (30 mg.kg-1) and aspirin DL-lysin groups (100 mg.kg-1). After determining control TF and CD values, animals received each analgesic intraperitoneally, and each procedure was repeated every 10 minutes for 30 or 40 minutes. NSAIDs produced a statistically significant increase in pain threshold for CD, but not for TF. In contrast, almost similar patterns of increase in pain thresholds for CD and TF were observed in morphine groups. The present study demonstrates that NSAIDs have a powerful antinociceptive effect on visceral pain evoked by CD.

[Assay of circulating thyroid stimulator determined by I- efflux]

The thyroid stimulating antibodies (TSAb) have been widely used as a clinical marker for diagnosis of hyperthyroidism due to Graves' disease. Immunoglobulins (IgG) of Graves' patients as well as TSH is known to stimulate cAMP production in FRTL-5 cells, a cell-line derived from normal rat thyroid. On the other hand, it has been shown that TSH-induced I- efflux in these cells is associated with production of inositolphosphate as well as intracellular Ca2+ increase. An attempt was made to determine whether Graves' IgG also can mimic such TSH action as a cause of Graves' disease. Polyethyleneglycol precipitated serum fraction of Graves' patients were prepared. The cells grown in the presence of TSH were incubated for 3 weeks in a Ham's 10 medium containing 1% calf serum, insulin and hydrocortisone for TSH depletion. After preincubation with 125I-iodide for 50 min to label intracellular iodide, the cells were challenged by serum samples for 1 min. The addition of normal pooled serum hardly affected the I- efflux. The Graves' immunoglobulin G fractions stimulated I- efflux dose-dependently. The mean potency of 12 patient's sera relative to the values of the pooled serum as 100% was 217 +/- 56.4%, which was significantly higher (p < 0.001) than that for 8 normal subjects (110 +/- 16.1%). The results obtained herein indicate that IgG of Graves' patients activate both adenylate aclase-cAMP system and a phospholipid-Ca2 system. I- efflux stimulating immunoglobulins (IESI) activity is a useful marker in making a diagnosis or determining a remission of hyperthyroidism due to Graves' disease.

Studies of diabetic nephropathy. I. Effects of storage time and temperature on microalbuminuria

The effect of storage time and temperature on the immunological turbidimetric measurement of a low concentration of albumin in urine was investigated. In storage at -20 degrees C, the albumin level decreased, but the rate of this decrease differed considerably among specimens. However, under storage at room temperature for 2 weeks, or at 4 degrees C for 5 weeks albumin levels did not show significant changes. At -40 degrees C and -80 degrees C there were only slight decreases. At -40 degrees C decreases were slightly greater than at -80 degrees C. Therefore, -80 degrees C was found to be the optimal temperature for long-term storage of urinary albumin. Some of the specimens showed a 50% decrease in albumin level after storage for 9 weeks at -20 degrees C, but remained unchanged after storage for the same period at -80 degrees C. A pair of specimens preserved at -20 degrees C and -80 degrees C were isolated by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). After electrophoresis, urinary proteins were stained by silver staining to observe bands, and albumin content was determined by immunoblotting. A decrease in albumin concentration was also observed by densitometric detection.

Homology-associated nonhomologous recombination in mammalian gene targeting

Nonhomologous (illegitimate) recombination of DNA underlies many changes in the genome. It involves no or little homology between recombining DNAs and has been considered unrelated with homologous recombination, which requires long homology. In mouse cells, however, we found recombination products whose sequences suggest that homologous interaction between DNAs caused nonhomologous recombination with another DNA. The intermediates of homologous recombination were apparently trapped at various stages and shunted to nonhomologous recombination. In one product, the nonhomologous recombination disrupted gene conversion. In another, it took place exactly at the end of long homology shared between two DNAs. This finding explains why gene targeting needs long uninterrupted homology and why mammalian homologous recombination is often nonconservative. We discuss possible consequences and roles of this type of homology-driven gene destruction mechanism.

[The measurement of insulin antibodies and insulin autoantibodies by enzyme-linked immunosorbent assay using recombinant human insulin antigen and its clinical application]

Insulin antibodies (IA) are detectable in the sera of most insulin-treated patients with diabetes mellitus. Antibodies to exogenous insulin sometimes cause clinical symptoms of insulin resistance, allergy, and local lipoatrophy. Although the frequency of these complications has diminished with the use of highly purified porcine insulin or recombinant human insulin, there are some patients with high titer of IA. Autoantibodies to insulin (IAA) are also described. IAA has been reported to be in association with both insulin-dependent diabetes mellitus (IDDM) and polyendocrine autoimmune disease. For many years these antibodies have been measured by radiobinding assay (RBA) in which the complexes are precipitated non-specifically by polyethylene glycol. In the present study we developed a rapid and quantitative enzyme-linked immunosorbent assay (ELISA) method for measuring IA and IAA using recombinant human insulin antigen. We applied this method to the samples obtained from patients with diabetes mellitus and autoimmune thyroid disease and then compared the results with those obtained from the RBA method. The calibration curve for ELISA was derived from the dilution curve of a single serum from a patient positive for insulin antibody, and the results were expressed arbitrarily as ELISA UNIT. The calibration curve was approximately linear on the log-log scale within the range of 0.1-2.0 at optical density (OD)450nm, (6.25-200 ELISA UNIT). The intra-assay (CV = 2.3-3.1%) and inter-assay (CV = 2.8-7.2%) precisions were acceptable. Recovery rate varied from 74.5% to 118.5% and dilution experiments showed good linearity. Specificity was demonstrated by substituting purified human IgG for the test serum and glucagon for insulin. Except for hemoglobin, coexisting substances in serum had almost no effect on ELISA. The range of ELISA UNIT (Mean +/- SD) of 83 normal sera was 12.7 +/- 4.6. Positivity for IA by ELISA (> normal Mean + 3SD) was 11 out of 58 (19.0%) and 26 out of 55 (47.3%) in patients with IDDM and with non-insulin-dependent diabetes mellitus (NIDDM) who were treated with insulin, respectively. Positivity for IAA by ELISA was 5 out of 173 (2.8%) and 1 out of 20 (5.0%) in patients with NIDDM without insulin therapy and hyperthyroidism due to Graves' disease, respectively. However, by RBA, we detected 4 other cases positive for IAA in NIDDM without insulin therapy and one case in Graves' disease. The present study demonstrates that the newly developed method of ELISA using recombinant human insulin antigen is clinically useful for measuring IA and IAA.

Inhibition by dexamethasone of retinoic acid-induced enhancement of leukotriene C4 synthesis in rat basophilic leukemia-1 cells

We investigated inhibitory actions of dexamethasone (DEX) on retinoic acid (RA)-induced enhancement of leukotriene C4 (LTC4) synthesis in rat basophilic leukemia-1 (RBL-1) cells. Cultured cells were preincubated with RA for 16 h with or without DEX, and generation of LTC4 was measured by high performance liquid chromatography in cell-free and intact cell systems. RA (0.1 microgram/ml) significantly potentiated calcium ionophore-stimulated production of LTC4 synthesis. DEX inhibited the RA-induced enhancement of LTC4 synthesis by up to approximately 95% in intact cells when stimulated with calcium ionophore. RA-induced LTC4 synthase activity, which was determined by enzyme assay, was also inhibited by DEX by 65% in a cell-free system. This discrepancy of inhibition between the intact and cell-free systems was due to a partial inhibition of phospholipase A2 activity by DEX in the intact cells. These results indicate that the production of LTC4 is predominantly regulated at a level of LTC4 synthase. The induction of new LTC4 synthase activity by RA and inhibition of the RA-induced activity by DEX are important regulatory mechanisms of LTC4 synthesis.

[Completely thrombosed large aneurysm of the distal middle cerebral artery: a case report]

A 19 year old male was admitted for evaluation after a seizure. Physical and neurological examination was normal. CT demonstrated an enlarged, high density mass in the right parietal lobe. MRI showed a homogeneous high intensity T1 weighted mass, surrounded by a low intensity T2 weighted rim in the right parietal lobe. Angiography did not show any abnormal findings. A diagnosis of cavernous angioma with primary bleeding in the subcortical region of the right parietal lobe was made after radiological examination. Histological examination showed a completely thrombosed aneurysm. The mechanism of the complete thrombosis and the growth of this large aneurysm and the shortcomings of radiological examination are discussed.

Microcirculatory dynamics of neuropeptide Y

We used the hamster cheek pouch microcirculation to investigate by intravital microscopy the effects of neuropeptide Y (NPY) on arteriolar diameter, leukocyte adhesion to microvascular endothelium, and postcapillary venular permeability. We applied NPY topically for 3 min at concentrations of 10(-7), 10(-9), and 10(-11) M. We quantified arteriolar diameter and permeability changes by digital image analysis. We used the mass of fluorescein isothiocyanate-Dextran 150 accumulated around postcapillary venules (10-30 microns) to calculate extravasation rates of macromolecules. We also measured the number of adhering white cells per 100-microns length of postcapillary venules using acridine orange to label white blood cells. At the applied doses, NPY did not alter either microvascular permeability to macromolecules or leukocyte adhesion to microvascular walls. NPY, in a dose-dependent manner, constricted arterioles ranging in control diameter from 10 to 60 microns. Vasoconstriction was strongest in arterioles ranging in diameter from 30 to 39 microns at a concentration of NPY of 10(-7) M. The Y1-type NPY receptor agonist, Leu31, Pro34-NPY, was as potent as NPY, whereas the carboxy-terminal fragment NPY 13-36 had no activity, indicating that the hamster cheek pouch microvasculature expresses the Y1 type of NPY receptor. We also blocked alpha-adrenergic receptors to test whether norepinephrine is required for NPY-induced vasoconstriction. This blockade did not inhibit the vasoconstriction caused by exogenous NPY. Our results demonstrate that (1) NPY modulates microvascular hemodynamics by changes in arteriolar diameter, (2) the NPY receptor on the hamster cheek pouch microvasculature is of the Y1 type, and (3) exogenous NPY-induced vasoconstriction is independent of the activity of endogenous norepinephrine.

[Enterococcus faecium obtained from surveillance cultures of the stool of the patients with hematological malignancies]

Surveillance cultures of the stool were obtained from 55 patients with hematological malignancies, who have been receiving norfloxacin or tosufloxacin during their neutropenic periods, from May, 1991 to September, 1992. Cultures were performed using 5% blood agar with piperacillin 300 micrograms/ml and amikacin 20 micrograms/ml and bacteria resistant to these antibiotics were analyzed further. Thirty-four over 55 patients were positive for enterococci and 22 strains of 23 examined were Enterococcus faecium. They are resistant to quinolones, aminoglycosides, cephalosporins and penicillins but not to vancomycin. Eighteen of them were also resistant to high-dose gentamicin. Appropriate measures should be used to prevent intrahospital spread of these resistant isolates.

[Alteration of serotype and drug susceptibility of some Pseudomonas aeruginosa isolates by exposure to human serum and polymorphonuclear leukocytes]

In the presence of 40% human serum plus polymorphonuclear leukocytes (PMNs, 10(7) cells/ml), changes in the surface properties of clinical isolates of P. aeruginosa were investigated by determining their serotypes and pyocin types as the markers. Furthermore, three isolates were tested for their susceptibility to anti-pseudomonal drugs and profiles of outer membrane proteins by the SDS-PAGE analysis. P. aeruginosa No. 21 which did not change in serotype and pyocin type after exposure to serum plus PMNs did not alter their susceptibility to all the drugs tested or their profiles of OMPs. In the case of P. aeruginosa No. 1-S, the variants with different serotypes were formed after the exposure, and increased their susceptibilities to some beta-lactams and norfloxacin which could penetrate into the bacterial cells through the porin channels of the outer membrane. Furthermore, two of the three type variants formed decreased their susceptibilities to gentamicin and polymyxin B which penetrated into the cells by the self-promoted uptake pathway. P. aeruginosa No. 1-R formed the serotype A and G variants with different pyocin types, only when exposed to serum plus PMNs for 24 hours, and the results were accompanied by the appearance of the porin D2 which was not detected in the parent cells. A small number of P. aeruginosa formed the variants with different serotypes and pyocin types owing to the alteration of their surface structures, when the cells were exposed to serum plus PMNs. The alterations were accompanied by the changes in some outer membrane proteins and the drug susceptibility to anti-pseudomonal drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

High prevalence of Neisseria gonorrhoeae strains with reduced susceptibility to fluoroquinolones in Japan

OBJECTIVE

To study the antibiotic susceptibility of Neisseria gonorrhoeae strains isolated in Japan and, in particular, to examine the possibility of emerging fluoroquinolone resistance.

MATERIALS AND METHODS

Sixty-nine strains of Neisseria gonorrhoeae isolated in 1992 were tested for susceptibility to 15 antibiotics including fluoroquinolones and were seroclassified. Twenty-seven strains isolated from 1981 to 1984 were also evaluated as controls.

RESULTS

The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1992 were 2.0, 1.0, and 0.5 microgram/ml, respectively. The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1981-84 (controls) were 0.25, 0.125, and 0.063 microgram/ml, respectively. These results indicate that the MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the strains from 1992 were 8-fold higher than those against the strains from 1981-84. However, there were no significant differences in susceptibility to beta-lactams, tetracyclines, macrolides, and spectinomycin between the isolates from 1992 and those from 1981-84. The majority of the isolates belonged to the WII/WIII serogroup. There was no relationship between fluoroquinolone resistance and serogroup.

CONCLUSIONS

Fluoroquinolones have been used frequently as first-line therapy and have provided excellent clinical efficacy for gonococcal infections for the last several years in Japan. However, our data indicate that a rapid decrease in the susceptibility of Neisseria gonorrhoeae to fluoroquinolones is occurring in our country.

Surgery for tumor thrombi in the right atrium and inferior vena cava of patients with recurrent hepatocellular carcinoma

This is a report on a 42-year-old woman with a tumor thrombus in the inferior vena cava and the right atrium caused by recurrent hepatocellular carcinoma. The tumor thrombus, which extended from the retrohepatic inferior vena cava into the right atrium close to the tricuspid valve was successfully resected using a cardiopulmonary bypass and total hepatic vascular exclusion. The cardiopulmonary bypass was established by cannulating the ascending aorta, the superior vena cava and the infrarenal vena cava, and was performed under moderate hypothermia and ventricular fibrillation. To reduce the duration of ventricular fibrillation, after the tumor thrombus had been removed from the right atrium into the suprahepatic inferior vena cava through the atriotomy, the atriotomy was closed. The intrapericardial or suprahepatic vena cava was then clamped. The caval tumor thrombus was removed using the total hepatic vascular exclusion technique through a vena cava incision. To reduce total hepatic vascular exclusion time the suprahepatic vena caval clamp was released after the caval tumor had been removed from the suprahepatic vena caval. The infrahepatic vena cava just below the hepatocaval junction was then clamped and the entire tumor thrombus was removed. The vena caval incision was closed without a prosthesis. The total hepatic vascular exclusion and vena caval exclusion times were 10 and 30 minutes, respectively. The ventricular fibrillation and total cardiopulmonary bypass times were 15 and 52 minutes, respectively. The operating time was 9 hours and 30 minutes and the total blood loss was 4,000 ml.

Role of endothelin 1 in hemorrhagic shock-induced gastric mucosal injury in rats

BACKGROUND/AIMS

Gastric microcirculatory disturbances are involved in the pathogenesis of stress ulcers; however, vasomodulators regulating this process are not fully understood. This study was conducted to investigate the role of endothelin 1 (ET-1) in hemorrhagic shock-induced gastric mucosal damage in rats.

METHODS

ET-1 contents in plasma and gastric mucosa were measured and gastric mucosal damage was evaluated during a control period, 60 minutes of ischemia, 15 minutes of reperfusion, and 30 minutes of postreperfusion. Next, effects of BQ-123, an endothelinA receptor antagonist, on the gastric mucosal damage and hemodynamics were studied.

RESULTS

Both plasma and mucosal ET-1 significantly increased after ischemia and reperfusion compared with the control values, but only mucosal ET-1 continued to increase after reperfusion, leading to the development of gastric mucosal damage. BQ-123, administered just before reperfusion, reduced mucosal damage in the postreperfusion period dose-dependently and improved mean gastric mucosal blood flow and mucosal hemoglobin oxygen saturation during the 30-minute postreperfusion period.

CONCLUSIONS

These results suggest that endogenous ET-1 plays an important role in the pathogenesis of hemorrhage shock-induced gastric mucosal damage through impairment of mucosal microcirculation. Further, endothelinA antagonists may have therapeutic benefits for shock-induced gastric mucosal damage.

Platelet-activating factor modulates microvascular transport by stimulation of protein kinase C

To investigate the possible involvement of protein kinase C (PKC) in platelet-activating factor (PAF)-stimulated microvascular responses, PKC inhibitors, sphingosine (SPH), 1-(5-isoquino-linylsulfonyl)-3-methylpiperazine (iso H-7), and calphostin C, were applied topically to the hamster cheek pouch, and PAF-elicited changes in microvascular permselectivity and arteriolar constriction were evaluated. Pretreatment with 10(-6) M SPH, 10(-5) M SPH, or 10(-10) M iso H-7 significantly reduced 10(-7) M PAF-induced increase in fluorescein isothiocyanate-Dextran 150 clearance (2,677.3 +/- 397.3, 2,985.3 +/- 350.7, and 2,689.3 +/- 256.0 vs. 4,784.0 +/- 474.7 nl.60 min-1.g-1, respectively). Calphostin C at 10(-7) M attenuated 10(-8) M PAF-induced increase in clearance (2,156.9 +/- 353.3 vs. 3,841.6 +/- 260.9 nl.60 min-1.g-1). Permeability changes were also measured by integrated optical intensity (IOI). Pretreatment with 10(-6) M SPH, 10(-5) M SPH, or 10(-10) M iso H-7 attenuated the maximal increment in IOI induced by 10(-7) M PAF (2,024.0 +/- 364.4, 1,690.0 +/- 525.2, and 2,432.8 +/- 655.3 vs. 4,255.9 +/- 695.6 U, respectively). Direct stimulation of PKC by phorbol dibutyrate increased clearance in dose-dependent fashion. Similarly, activation of PKC with phorbol myristate acetate increased IOI values. The PAF-induced arteriolar constriction was not blocked by the PKC inhibitors. Our results suggest that PKC represents a biochemical pathway involved in the PAF modulation of microvascular permeability but not of arteriolar constriction.

Clinical value of electrophysiologic study in patients with nonsustained ventricular tachycardia

Electrophysiologic study (EPS) was performed in 68 consecutive patients with nonsustained ventricular tachycardia (VT) detected by ambulatory monitoring. The study group consisted of 11 patients with coronary artery disease, 11 patients with idiopathic cardiomyopathy or myocarditis, 2 patients with valvular heart disease, 1 patient with post atrial septal defect repair and 43 patients with a normal heart. Syncope or presyncope was found in 34 percent of these patients. EPS was performed after all antiarrhythmic drugs were withdrawn for more than 5 days. Nonsustained VT, sustained VT, and ventricular fibrillation were induced in 21%, 4%, and 4% respectively. VT was induced more frequently in patients with organic heart diseases but it was not related to the history of syncope. Ejection fraction in the inducible patients was not different from that of the noninducible patients. During the mean follow up period of 31 months, there was no cardiac death. The results suggest that the prognosis of patients with nonsustained VT is good and the clinical significance of their EPS findings seems to be limited.

Ultrastructure of the neuromuscular junction of vasomotor nerves in the microvasculature of human dental pulp

Vasomotor nerves in human dental pulp were more closely related to arterioles than to venules. Most were composed of unmyelinated fibres, which were mainly adrenergic. They appeared close to arterioles that were surrounded by a few layers of contractile smooth-muscle cells. The smaller arterioles with a diameter of 10-15 microns received a more intimate innervation by vasomotor nerves than did the larger. These vessels occasionally showed much narrower neuromuscular junctions than previously reported. Most of these nerve fibres were identified as adrenergic by the presence of chromaffin-positive synaptic vesicles detected by ultrastructural enzyme histochemistry. Their function appeared to be to regulate the blood flow and/or the blood pressure by stimulating smooth-muscle cells, resulting in contraction and a change in the calibre of the vessels. Capillaries and venules, which have a higher permeability, received weaker innervation by the vasomotor nerves than did arterioles. The intimate relation between vasomotor nerves and arterioles is related to the function of dental pulp in normal and pathological conditions.

[Formation of drug-induced serotype variants of Pseudomonas aeruginosa: changes in biochemical properties, drug susceptibility and outer membrane proteins]

The serotype variants were formed in some isolates of Pseudomonas aeruginosa in the presence of anti-pseudomonal drugs in vitro. Pyocin type, various biochemical properties and drug susceptibility of these variants were compared with those of the parent cells. Furthermore, the patterns of outer membrane proteins were also examined for some respective parent and variant cells by the SDS-PAGE and compared with their drug susceptibilities. In P. aeruginosa No. 1-S (serotype E) and No. 1-R (serotype C), simultaneously isolated from the identical specimen of the infectious patient, the serotype variants were formed by anti-pseudomonal drugs and accompanied by changes in pyocin types, some biochemical properties and susceptibilities to various kinds of anti-pseudomonal drugs. When the profiles of outer membrane proteins of P. aeruginosa No. 1-R parent and two variant cells were evaluated by the SDS-PAGE, the quantitative differences of the porin proteins between the parent and variant cells were well related to their drug susceptibilities. Although eight variant cells with other serotype were formed from the parent cells (serotype A) of P. aeruginosa No. 13, four variants with serotype M and one non-typable variant showed changes in drug susceptibility such as resistance to imipenem only and no changes in biochemical properties. On the other hand, three other variants showed marked changes in two kinds of biochemical properties and in susceptibilities to various kinds of anti-pseudomonal drugs. From the results of SDS-PAGE, it was found that the porin protein profiles of outer membranes of these parent and variant cells except a few cells which corresponded to their drug susceptibility.

DNA double-strand break repair: genetic determinants of flanking crossing-over

Whether or not homologous interaction of two DNA molecules results in crossing-over of the flanking sequences is an important decision in view of genome organization. Several homologous recombination models, including the double-strand break repair models, explain this decision as choice between two alternative modes of resolution of Holliday-type intermediates. We have demonstrated that a double-strand gap can be repaired through gene conversion copying a homologous duplex, as predicted by the double-strand break repair models, in the RecE pathway of Escherichia coli. This gap repair is often accompanied by crossing-over of the flanking sequences. Mutations in ruvC and recG, whose products interact with Holliday structures in vitro, do not block double-strand gap repair or its association with flanking crossing-over. However, two mutations in the recJ gene, which encodes a single-strand 5'-->3' exonuclease, severely decrease association of flanking crossing-over. Two mutations in the recQ gene, which encodes a helicase, moderately decrease association of flanking crossing-over by themselves and suppress the severe effect of a recJ mutation. Similar relationships of recJ and recQ mutations are observed in cell survival after ultraviolet light irradiation, gamma-ray irradiation, and H2O2 treatment. We discuss how cooperation of the recQ gene product and the recJ gene product brings about double-strand break repair accompanied by flanking crossing-over. We also discuss how this reaction is related to repair of chromosome damages.

[Advanced breast cancer with remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy: a case report]

A 67-year-old advanced breast cancer patient with multiple bone metastases showed a remarkable response to the combination therapy of mitoxantrone (MIT) and medroxyprogesteron acetate (MPA) after failure of anthracycline therapy. Eight course of CTF (cyclophosphamide, THP-adriamycin, 5-fluorouracil) and subsequent 4'-epi-adriamycin were performed for locally advanced breast cancer and multiple bone metastases, but the ulcerated breast cancer enlarged. Then the combination therapy of MIT (10 mg/day) and MPA (1,200 mg/day) was carried out. Seven months after treatment, the ulcerated breast cancer disappeared completely and the serum levels of CA 15-3, TPA and CEA decreased within the normal range. These results suggest that combination therapy with mitoxantrone may well be effective against the anthracycline-resistant breast cancer.