MR Imaging Detection of CNS Lesions in Tuberous Sclerosis Complex: The Usefulness of T1WI with Chemical Shift Selective Images.

BACKGROUND AND PURPOSE: CNS lesions of tuberous sclerosis complex are diagnosed mainly by T2WI, FLAIR, and sometimes T1WI with magnetization transfer contrast. The usefulness of T1WI with chemical shift selective images was recently reported in focal cortical dysplasia type IIb, which has histopathologic and imaging features similar to those of tuberous sclerosis complex. We investigated the usefulness of the T1WI with chemical shift selective images in detecting CNS lesions of tuberous sclerosis complex. MATERIALS AND METHODS: We retrospectively reviewed 25 consecutive patients with tuberous sclerosis complex (mean age, 11.9 [SD, 8.9] years; 14 males) who underwent MR imaging including T1WI, T1WI with magnetization transfer contrast, T1WI with chemical shift selective, T2WI, and FLAIR images. Two neuroradiologists assessed the number of CNS lesions in each sequence and compared them in 2 steps: among T1WI, T1WI with magnetization transfer contrast and T1WI with chemical shift selective images, and among T2WI, FLAIR, and T1WI with chemical shift selective images. We calculated the contrast ratio of the cortical tubers and of adjacent normal-appearing gray matter and the contrast ratio of radial migration lines and adjacent normal-appearing white matter in each sequence and compared them. RESULTS: T1WI with chemical shift selective images was significantly superior to T1WI with magnetization transfer contrast for the detection of radial migration lines and contrast ratio of radial migration lines. There was no significant difference between T1WI with chemical shift selective images and T1WI with magnetization transfer contrast for the detection of cortical tubers and the contrast ratio of the cortical tubers. Both T2WI and FLAIR were statistically superior to T1WI with chemical shift selective images for the detection of cortical tubers. T1WI with chemical shift selective images was significantly superior to T2WI and FLAIR for the detection of radial migration lines. CONCLUSIONS: The usefulness of T1WI with chemical shift selective images in detecting radial migration lines was demonstrated. Our findings suggest that the combination of T1WI with chemical shift selective images, T2WI, and FLAIR would be useful to evaluate the CNS lesions of patients with tuberous sclerosis complex in daily clinical practice.

Microhardness and Roughness of Infiltrated White Spot Lesions Submitted to Different Challenges.

A white spot lesion is the first clinical sign of a caries lesion and represents mineral loss from the enamel subsurface. The purpose of this study was to evaluate the microhardness and surface roughness of white spot lesions after application of a resin infiltrant and subjection to different challenges. Caries-like lesions were induced in bovine enamel discs (n=50), and the specimens were randomly divided into five study groups (n=10): demineralized enamel (negative control, G1), infiltrated enamel (G2), infiltrated enamel submitted to brushing (G3), infiltrated enamel submitted to pH cycling (G4), and infiltrated enamel submitted to artificial aging (G5). Half of each enamel surface was used as its own positive control. Roughness data were analyzed using the Kruskal-Wallis test followed by the Dunn test. Results from microhardness were analyzed by two-way analysis of variance, followed by the Tukey test for multiple comparisons. The level of significance was set at 5%. Microhardness and roughness values obtained from the test side of the specimens were significantly lower compared with the sound enamel for all groups. Microhardness values obtained for G2, G3, and G5 were not significantly different. Values found for G1 were significantly lower compared with those for G2, G3, and G5. The lowest microhardness values were observed for G4, which was significantly different from the other groups. Surface roughness was not significantly different between G2 and G3. The resin infiltrant presented superiority over the unprotected white spot lesions, as they were more resistant to mechanical and aging challenges. However, resin infiltration was not able to reestablish the properties of sound enamel and was not resistant to a new cariogenic challenge.

Renin-angiotensin system and fibronectin gene expression in Dahl Iwai salt-sensitive and salt-resistant rats.

OBJECTIVE: The tissue renin-angiotensin system and extracellular matrix are involved in the cardiovascular hypertrophy and remodeling induced by hypertension. In this study, we examined the gene expression of the tissue renin-angiotensin system and fibronectin in inbred Dahl Iwai salt-sensitive and salt-resistant rats. MATERIALS AND METHODS: Eight pairs of 6-week-old male Dahl Iwai salt-sensitive and salt-resistant rats were fed either a low- or high-salt diet (0.3% or 8% NaCl, respectively) for 4 weeks. Activities of the circulating renin-angiotensin system were measured by radioimmunoassay and the gene expression of tissue angiotensinogen, the angiotensin II type 1 receptor (AT1) and fibronectin were analyzed by Northern blot analysis. RESULTS: Salt loading significantly increased blood pressure and produced cardiovascular hypertrophy and nephrosclerosis in the salt-sensitive rats. Activities of the circulating renin-angiotensin system were lower in salt-sensitive rats than in salt-resistant rats fed the low-salt diet, and salt loading lowered these activities in salt-resistant rats but not in salt-sensitive rats. In salt-resistant rats, salt loading increased renal, cardiac and aortic angiotensinogen, AT1 and fibronectin messenger (m)RNA expression except for aortic fibronectin mRNA expression. In contrast, in the salt-sensitive rats, salt loading stimulated the expression of cardiac fibronectin and aortic angiotensinogen, AT1 and fibronectin mRNAs. Furthermore, the cardiac and aortic fibronectin mRNA levels in salt-sensitive rats were higher than those in salt-resistant rats when both strains were fed the high-salt diet. CONCLUSIONS: These results demonstrate that the expression of tissue angiotensinogen, AT1 and fibronectin mRNAs is regulated differently in Dahl Iwai salt-sensitive and salt-resistant rats, and indicate that salt-mediated hypertension activates the cardiac fibronectin gene independently of the tissue renin-angiotensin system and stimulates the aortic fibronectin gene with activation of the tissue renin-angiotensin system.

Tissue-specific changes of type 1 angiotensin II receptor and angiotensin-converting enzyme mRNA in angiotensinogen gene-knockout mice.

This study examined whether type 1 angiotensin II receptor (AT1) and angiotensin-converting enzyme (ACE) mRNAs are regulated during dietary salt loading in angiotensinogen gene-knockout (Atg-/-) mice which are genetically deficient in endogenous production of angiotensin II. Wild-type (Atg+/+) and Atg-/- mice were fed a normal-salt (0.3% NaCl) or a high-salt (4% NaCl) diet for 2 weeks. The mRNA levels were measured by Northern blot analysis. In Atg+/+ mice, concentrations of plasma angiotensin peptides were decreased by salt loading, whereas the treatment increased the brainstem, cardiac, pulmonary, renal cortex, gastric and intestinal AT1 mRNA levels. Salt loading also enhanced renal cortex ACE mRNA levels in Atg+/+ mice. Although plasma angiotensin peptides and urinary aldosterone excretion were not detected in Atg-/- mice, salt loading increased blood pressure in Atg-/- mice. In Atg-/- mice, pulmonary, renal cortex, gastric and intestinal AT1, and renal cortex and intestinal ACE mRNA levels were higher than those in Atg+/+ mice. However, salt loading upregulated AT1 mRNA expression only in the liver of Atg-/- mice, and the treatment did not affect ACE mRNA levels in Atg-/- mice. Furthermore, although the levels of ACE enzymatic activity showed the same trend with the ACE mRNA levels in the lung, renal cortex and intestine of both Atg-/- and Atg+/+ mice, the results of radioligand binding assay showed that cardiac expression of AT1 protein was regulated differently from AT1 mRNA expression both in Atg-/- and Atg+/+ mice. Thus, expression of AT1 and ACE is regulated by salt loading in a tissue-specific manner that appears to be mediated, at least partly, by a mechanism other than changes in the circulating or tissue levels of angiotensin peptides.

Angiotensin II receptors in cardiac left ventricles of Dahl rats.

1. Dahl Iwai salt-sensitive (DS) rats have been reported as becoming hypertensive with left ventricular hypertrophy (LVH) and heart failure when on a high-salt diet. Their circulating renin-angiotensin system (RAS) has been reported to be suppressed. To evaluate the role of angiotensin II (AngII) type 1 and type 2 receptors (AT1 and AT2, respectively) in LVH, we compared cardiac AT1 and AT2 receptors in 10-week-old DS rats and Dahl Iwai salt-resistant (DR) rats. 2. Seven pairs of 6-week-old male DS and DR rats were fed either a low- or high-salt diet (0.3 or 8% NaCl, respectively) for 4 weeks. Left ventricular AngII receptors were measured by radioligand binding assays using [125I]-[Sar1,Ile8]-AngII in plasma membrane fractions from these four groups. The AT1 and AT2 receptors were distinguished using their specific antagonists CV 11974 and PD 123319, respectively. 3. The high-salt diet increased blood pressure and the left ventricle:bodyweight ratio in DS rats. However, neither Bmax for AT1 and AT2 receptors nor Kd for [125I]-[Sar1,Ile8]-AngII differed between the groups. These results are different from those of other reports of pressure-overload LVH, such as spontaneously hypertensive rats or renovascular hypertension rats, in which AT1 and AT2 receptors were reported to be up-regulated.

Relationship between hepatic angiotensinogen mRNA expression and plasma angiotensinogen in patients with chronic hepatitis.

Recent association and linkage studies suggested that angiotensinogen may play an important role in the pathogenasis of essential hypertension. However, there is little information in human concerning a relationship between plasma angiotensinogen levels and the angiotensinogen mRNA expression in the liver, which is the main production site of angiotensinogen. Therefore, the aim of this study was to examine whether hepatic angiotensinogen gene expression determines the level of circulating angiotensinogen and the activity of the renin-angiotensin system in humans. The subjects were 36 patients with chronic hepatitis. Blood was collected from each patients for estimation of plasma renin activity, plasma angiotensinogen and angiotensin II concentrations and several parameters of liver function. In addition, total RNA was isolated from liver biopsy specimens, which were then used to measure angiotensinogen mRNA with Northern blot analysis. Levels of angiotensinogen mRNA were detected easily in the liver biopsy specimens in all of the patients. Hepatic angiotensinogen mRNA levels were positively correlated with plasma angiotensinogen levels (r=0.41, P=0.013). In contrast, hepatic angiotensinogen mRNA levels did not show any significant relationship with plasma renin activity, plasma angiotensin II concentration, histological subgroup of hepatitis, histological activity index and parameters of liver function tests. The present study demonstrated, for the first time, that hepatic angiotensinogen mRNA levels correlated with plasma angiotensinogen concentration in humans.

[Treatment outcome of 288 cases of renal cell carcinoma].

The clinical outcome was analyzed on 288 patients with renal cell carcinoma who were admitted to the Niigata Cancer Center Hospital during the 33 years from 1961 to 1993; 254 patients had had nephrectomy and 244 of them had undergone curable operations. The survival rate was calculated by the Kaplan-Meier method. The 3-, 5- and 10-year survival rates by all causes of death in all 288 patients were 64.8, 55.9 and 36.4%, respectively. According to the stage based on the general rules for clinical and pathological studies on renal cell carcinoma (The 2nd Edition), the 5-year survival rate was 89.5, 78.7, 51.1 and 13.7% for stages I (n = 31), II (n = 128), III (n = 38) and IV (n = 83), respectively. The 5-year survival rate for the patients (n = 88) from 1961 to 1985 was 40.9%, while the rate for the patients (n = 200) from 1986 to 1993 was 64.3%. This improvement of survival rate for the patients after 1986 was brought by the increase of the stage I or II cases and by the improvement of the survival in the stage III cases after 1986. The 5-year disease-specific survival rate for the patients over 50 years old was 55.5%, while the rate for the patients under 50 years old was 83.6%. Female, low pT, low grade and small tumor size were proven to be favourable prognostic factors in renal cell carcinoma.

Central diabetes insipidus caused by pituitary metastasis of lung cancer.

Tumor metastasis to the hypophyseal system has rarely been reported with either clinical or radiographic evidence. A 52-year-old woman presented with polydipsia, polyuria, and loss of appetite. She was diagnosed as having diabetes insipidus caused by pituitary micrometatasis of lung adenocarcinoma. After she had been treated with radiation therapy to the pituitary gland, the gland size was reduced as confirmed by magnetic resonance imaging, and her urine volume decreased. However, meningitis carcinomatosa appeared later. This was a rare case of secondary diabetes insipidus due to pituitary metastasis of lung cancer.

[Effects of cross-linking agent on the bond strength of 4-META/MMA-TBB resin].

A cross-linking agent was added to increase the bonding strength of Superbond C & B by improving its cohesiveness. PMMA powder, which was copolymerized with 0.5% (w/w) neopentylglycol dimethacrylate as a cross-linking agent, was used for the preparation of Superbond C & B. The bonding of Superbond C & B to which the cross-linking agent had been added was then examined by the pull-out test using an alloy with different levels of surface roughness prepared by two surface-processing methods (polishing with #600 waterproof abrasive paper or 50 microns sandblast processing). The results were as follows: 1. Superbond C & B had a bonding strength of 205 kgf/cm2 after polish processing of the alloy with #600 waterproof abrasive paper and 199 kgf/cm2 after 50 microns sandblast processing. The t-test showed no significant difference between the two types of processing. 2. Superbond C & B to which the cross-linking agent had been added showed a bonding strength of 285 kgf/cm2 in the material processed with #600 waterproof abrasive paper and 347 kgf/cm2 in that processed with 50 microns sandblast processing. 3. Among various combinations of bonding agents and surface processing methods, the combination of Superbond C & B with the cross-linking agent and 50 microns sandblast processing showed the highest values under all conditions.

[Studies on thermal stimulation accompanying visible-light irradiation].

Visible-light-cured composite resin is one of the most frequently used materials in clinical practice. The use of this material inevitably involves dental pulp stimulation, i.e., thermal stimulation due to visible-light irradiation, during the restoration procedure. To determine the variations of temperature involved in visible-light irradiation, the author examines differences in temperature generated by various types of visible-light curing units. Changes in the temperature under varying conditions of irradiation were also examined. The results were as follows: 1) Among the visible-light curing units used in the present study, the highest temperature was obtained from Translux CL (a rise of 17 degrees C) whereas Hiliomat showed the lowest value (a rise of 7 degrees C). 2) The temperature increased with prolongation of irradiation time, reaching a maximum level (a rise of 15 degrees C) at 60s. 3) The temperature increased with shortening of irradiation distance, reaching a maximum level (a rise of 20 degrees C) at 3mm.

[Temporary restoration using light-cured resin].

In spite of various problems involved in chemically cured resin (self-curing resin), e.g., irritability, and heat and shrinkage at polymerization, it has traditionally been the material of choice in the production of temporary restorations. However, light-cured resin, which does not have the disadvantages of chemically cured resin, has recently been developed and applied to clinical treatment. The present study was conducted to examine the clinical application of light-cured resin to temporary crowns. Two types of light-cured resin and one type of chemically cured resin were examined for their mechanical properties. The properties involved in handling and setting, and the methods of producing crowns were also studied. The results were as follows: 1) In the tensile strength test, there was no significant difference between the two types of light-cured resin, i.e., Triad and Unifast LC. The tensile strength of Unifast, a chemically cured resin, was slightly greater than the others, the difference being significant. 2) The Vickers hardness test showed no significant differences between the three types of resin. 3) The mechanical properties of Triad were not influenced by differences in the curing unit (the unit for general oral use or exclusive use) used for polymerization. 4) The test of setting properties revealed that Unifast LC needed longer than Unifast from the 2nd through the 4th clinical stage. In particular, Unifast LC required about 2.5 times the duration needed by Unifast at the 2nd stage in the tray method. 5) The heat generation test showed that the exothermic temperature in Unifast was significantly higher than in the two types of light-cured resin. 6) Heat generation associated with light curing was noted during the use of a light-curing unit for oral use.

[Studies on bond strength and hardness of base materials].

Since base materials are used in the construction of abutment teeth and the cavity walls of the teeth with healthy pulp, they need considerable bonding and mechanical strength depending on the site of application. In the present study we examined bonding strength, Martens-Mayer hardness and Vickers hardness of base materials in comparison with natural dentin in order to reevaluate them in terms of prosthetic materials and to provide assessment criteria for their application to prosthetic treatment. The results were as follows: 1) The bonding test showed the lowest value (4.6kgf/cm2) in calcium hydroxide FR (HFR) and the highest (47.9kgf/cm2) in HY-Bond polycarboxylate cement (CHC), a type of polycarboxylate cement. 2) In the test of bonding strength with various types of cement, calcium hydroxide preparations and zinc phosphate cement showed low values (4.6-23.5kgf/cm2) while polycarboxylate cement and glass-ionomer cement showed relatively high values (17.8-40.5kgf/cm2). 3) The Martens-Mayer hardness test showed the highest value (10.82 x 10(4] in dentin cement (GDE) and the lowest (1.09 x 10(4] in propack (EPR). 4) The Vickers hardness test showed the highest value (82) in neo-protect cement (ZPR) and the lowest (1) in propack (EPR). 5) In both Martens-Mayer and Vickers hardness tests with various types of cement, zinc phosphate cement and glass- ionomer cement showed high values, while low values were obtained in calcium hydroxide preparations and zinc-oxide eugenol cement. 6) Zinc phosphate cement and glass-ionomer cement showed no statistically significant differences from natural dentin in either Martens-Mayer hardness or Vickers hardness.

[Statistical analyses on over ten years survivals in Hokkaido under chronic dialysis therapy].

In Hokkaido, there were 305 chronic dialysis patients surviving more than ten years as of July 31, 1985. All patients except for one (CAPD) have been placed under hemodialysis. About 73% of them were introduced into a dialysis therapy in their thirties and chronic glomerulonephritis was extremely predominant as for the underlying disease. 93.2% of the cases possessed internal AV-fistulae using own vessels and other types of blood access remained only 6.8%. Hematocrit (Hct) was 27.5% on average of 305 cases. The value was fairly satisfactory but it must be noted that Hct of 33 patients (10.8% of all) was less than 20%. Severe anemia is still one of major complication in chronic dialysis patients. Characteristic complications, which have been increasing in frequency in parallel with prolonged dialysis length, became clarified: renal osteodystrophy, secondary hyperparathyroidism, carpal tunnel syndrome, persistent hypotension and so on. The former two are strongly related to Ca & P metabolism and some of the long-term survivals require parathyroidectomy. It is now estimated that carpal tunnel syndrome is induced by accumulation and deposition of beta 2-microglobulin, which increases in blood progressively if used Cuprophane membrane dialyser. Patients with CTS must be placed under surgical intervention, which relieves the symptoms effectively and the prophylaxis might require protein-permeating dialyser.

Kinetic study of the polymorphic transformations of phenylbutazone.

The polymorphic transformations of phenylbutazone from metastable forms alpha and beta to stable form delta were studied quantitatively at four temperature and five humidity levels by X-ray powder diffractometry. The transformation of form alpha conformed with the Avrami-Erofe'ev kinetic model and form beta conformed with apparent first-order kinetics. In the two transformation systems, the induction periods depended on the storage conditions and were prolonged with lowering of temperature and humidity. The transformation rate of form alpha was not affected by humidity, whereas that of form beta increased according to a rise in humidity. The temperature dependency of the transformation rate constant was remarkable. The Arrhenius treatment was applicable to the beta----delta transformation at low temperatures. The overall half-life, including induction period, revealed that form alpha was more stable than form beta under any storage condition. A good linear relationship existed between the induction period and the transformation rate constant, irrespective of the storage conditions. The scanning electron photomicrographs of forms alpha and beta demonstrated that acicular crystals of form delta grew as the transformation progressed. This could be confirmed as the change in particle diameter of the samples.