A high-performance liquid chromatographic assay for the determination of itraconazole concentration using solid-phase extraction and small sample volume

Itraconazole has been shown to be highly effective against a broad spectrum of fungi, particularly aspergillus. In order to achieve the desired pharmacological effect, the itraconazole plasma concentration should be > 250 ng/ml. We developed a high-performance liquid chromatography assay for the rapid determination of plasma itraconazole concentration using solid-phase extraction and small sample volume. The assay possessed linearity up to 5,000 ng/ml, sensitivity of 50 ng/ml, average recovery of 100.8%, and run-to-run precision (n = 10) for concentrations of 100, 200, and 500 ng/ml of 12, 6.6, and 5.8%, respectively. Furthermore, the assay proved to be free of interference from 48 commonly prescribed and some over-the-counter medications. We conclude that the method described here is ideally suited for the therapeutic monitoring of itraconazole.

Serotonergic cells in nucleus raphe pallidus provide tonic drive to posterior cricoarytenoid motoneurons via 5-hydroxytryptamine2 receptors in cats

Microinjection of serotonin and 5-hydroxytryptamine2 (5-HT2) agonist 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) in nucleus ambiguus caused excitation of posterior cricoarytenoid (PCA) muscles of the larynx in anesthetized, spontaneously breathing cats. Intravenous administration of 5-HT2 antagonist ketanserin produced complete block of excitatory effect of DOM injection. Electrical stimulation of nucleus raphe pallidus caused excitation of PCA activity, that was blocked by pretreatment of ketanserin. These results indicate that serotonergic cells in the raphe pallidus provide tonic drive to medullary PCA motoneurons through 5-HT2 receptors.

Intraoperative risk factors associated with hepatic resection

Risk factors associated with complications following hepatic resection were investigated retrospectively in 121 patients between January 1987 and April 1992. Fifty-seven patients recovered uneventfully, but 64 suffered post-operative complications and 15 died within 3 months. All those who died had suffered from hyperbilirubinaemia or bleeding and/or coagulopathy, which were considered critical complications after hepatic resection. Risk factors following hepatic resection were investigated statistically. Stepwise logistic regression analysis showed that serum levels of cholinesterase, the histology of the remaining liver and the volume of intraoperative blood loss were significantly associated with major complications (odds ratio 0.02, 5.14 and 4.97 respectively). Coexisting liver cirrhosis, deterioration of liver protein synthesis and massive intraoperative blood loss are important risk factors following hepatic resection.

Stimulation of cultured vascular smooth muscle cell proliferation by thrombospondin is potentiated by zinc

The interaction of zinc sulfate with thrombospondin (TSP) derived from bovine platelets, on the proliferation of bovine aortic smooth muscle cells was investigated using cell culture. Zinc alone has no effect but potentiates the stimulatory effect of TSP on the incorporation of [3H]thymidine into the acid-insoluble cell fraction. Other heavy metals including copper, lead, manganese and nickel did not exhibit a similar effect. In bovine aortic endothelial cells, [3H]thymidine incorporation was stimulated by zinc alone and suppressed by TSP alone; the stimulation by zinc was significantly reduced by TSP. In human fibroblastic IMR-90 cells, [3H]thymidine incorporation was stimulated by either zinc or TSP; a simultaneous treatment with zinc and TSP showed an additive effect. The present data suggest that zinc may be a unique heavy metal that potentiates the proliferation of vascular smooth muscle cells stimulated by TSP; in addition, such an interaction was observed selectively in this cell type. Since a large amount of TSP is released from alpha-granules of aggregated platelets, zinc may augment TSP activity which is involved in the physiology of vascular tissues.

Clinical study on prognosis of metastatic prostate cancer based on extent of disease on pretreatment bone scintigraphy

The pretreatment bone scintigrams of 58 patients with prostate cancer with bone metastasis were reviewed and the prognostic value of the initial extent of bone involvement was compared with that of other pretreatment characteristics. The extent of bone metastasis revealed by the scan was related to survival. The serum level of alkaline phosphatase at pretreatment and pathological grade also had some predictive value. Although the pathological grade of primary tumours was related to prognosis, the survival of patients with the same histological grade differed according to the initial extent of disease; patients with extensive disease along with raised serum alkaline phosphatase (twice or more as high as the cut-off value) had poorer prognosis than did those with lower alkaline phosphatase or smaller extent of disease. The extent of bone involvement in combination with serum alkaline phosphatase level therefore apparently has higher prognostic value than does disease extent alone.

Induction of metallothionein by thrombin in cultured vascular endothelial and smooth muscle cells

Metallothionein induction by thrombin was investigated using a culture system of vascular endothelial and smooth muscle cells. It was found that the protease induced metallothionein in endothelial cells derived from human aorta and umbilical vein as well as bovine aorta in a concentration-dependent manner. Thrombin also induced metallothionein in vascular smooth muscle cells derived from bovine aorta but not in cells derived from human, rabbit and rat aortas. In bovine aortic endothelial and smooth muscle cells, induction of metallothionein by thrombin was unaffected by the protein kinase C inhibitor staurosporine; in addition, a protein kinase C activator, phorbol 12-myristate 13-acetate, failed to induce metallothionein, suggesting that the induction by thrombin occurred through pathway(s) other than protein kinase C activation. It is suggested that metallothionein may be induced during hemostasis in the vascular tissue through protein kinase C-independent pathway(s).

[Predicting renal stone fragility against ESWL]

BACKGROUND

The mineral content (MC) and mineral density (MD) of renal stones, measured by dual energy X-ray absorptiometry, were compared with the experimental and clinical results of stone disintegration by shock wave.

METHODS AND RESULTS

In the experimental study, the MC and MD values correlated significantly with the total shock wave energy used, with a correlation coefficient (r) for MC being 0.814 and for MD, 0.706 (n = 46). The mean MC and MD values were 0.521 +/- 0.387g and 0.317 +/- 0.121 g/cm2 (n = 14) respectively in patients undergoing clinically successful ESWL, while those were 4.27 +/- 6.19g and 0.626 +/- 0.302 g/cm2 (n = 6) respectively in patients undergoing clinically unsuccessful ESWL. Those values differed significantly between the two groups (p < 0.05, p < 0.01, respectively). The combination of MC, MD and area values of a stone was shown to be the best predictor of treatment outcome, with a predictive value of incorrect discrimination being 17% and that of correct discrimination, 85% using linear discriminant analysis.

CONCLUSION

The mineral content and mineral density, measured by dual energy X-ray absorptiometry, may provide the best prediction of outcome of patients undergoing ESWL treatment.

Solitary renal melanoma? A case with long survival after initial treatment

A case of a solitary melanocytic renal tumor with no apparent primary lesion or metastasis is reported. Pathologically the tumor was composed of cells with brown pigmentation that strongly reacted to monoclonal antibody HMB-45 immunohistochemically. Few mitotic figures, mild nuclear atypia and nucleolar prominence were observed. These findings confirmed that the tumor cells were melanogenetic but the malignant potential of the tumor was low in comparison to that of typical malignant melanoma. The patient is doing well 44 months after partial resection of the renal tumor and postoperative chemotherapy. The interesting pathological feature may account for the unique clinical course.

Cerebral ATP-sensitive potassium channels during acute reduction of carotid blood flow

The ATP-sensitive potassium channels (KATP) are activated either by a decrease in intracellular ATP content or by a lowering of the ATP-ADP ratio such as during stroke. We studied the role of cerebral KATP on arterial pressure during acute reduction of cerebral blood flow in 12-week-old male Wistar rats anesthetized with urethane by recording arterial pressure and heart rate continuously. After bilateral ligation of the common carotid arteries, glibenclamide, a specific blocker of KATP, was injected intracerebroventricularly into the cerebral lateral ventricle. Glibenclamide elicited a sustained vasopressor response in a dose-dependent manner in rats with bilateral carotid artery ligation (10 nmol, +15 +/- 2 mm Hg; 1 nmol, +5 +/- 1 mm Hg, P < .01 versus vehicle), but hemodynamic alterations were barely recorded with glibenclamide in sham-operated control rats. The abdominal sympathetic discharge was not increased significantly enough to explain the pressor mechanism. Similarly, pretreatments with intravenous injections of bunazosin, an alpha 1-adrenoceptor antagonist, did not affect the pressor response of intracerebroventricular glibenclamide. To investigate the vasopressor mechanism further, we measured plasma and pituitary concentrations of arginine vasopressin and determined the effects of vasopressin receptor antagonists. The intracerebroventricular injections of glibenclamide significantly increased the plasma concentration of vasopressin (P < .05) and significantly decreased the pituitary concentration of vasopressin (P < .05) in rats with bilateral carotid artery ligation. Intravenous pretreatment with the vasopressin V1 receptor antagonist OPC-21268 abolished the vasopressor response to intracerebroventricular glibenclamide (+16 +/- 2 versus +1 +/- 1 mm Hg, P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of the neonatal vitamin A exposure on behaviors of adult rats

The effects of neonatal vitamin A exposure on six behavioral parameters in adult Wistar rats were investigated. Newborn male rats were injected intraperitoneally with 80,000 IU/kg/day of retinol palmitate (vitamin A) dissolved in physiological saline or vehicle alone (controls) during 1-5 days after birth. The animals were examined using the open field test (at 36 weeks of age), the rotarod test (38 weeks), the Biel water-maze test (40 weeks), the conditioned avoidance test (42 weeks), the running-wheel activity with pentobarbital challenge test (44 weeks), and the tail flick test (45 weeks). The vitamin A-exposed rats made significantly more errors and took significantly longer times in the Biel water-maze test, and showed significantly slower responses in the tail flick test than the controls. No significant effects of treatment with vitamin A were observed in any of the other behavioral tests. These results indicate that a long-lasting defect in learning in water-maze task and depression of the heat-pain response are induced in rats exposed neonatally to vitamin A.

Stimulatory effect of lead on the proliferation of cultured vascular smooth-muscle cells

The effect of lead nitrate on the DNA synthesis of cultured bovine aortic smooth-muscle cells has been studied. Lead at 0.5-10 microM stimulated the incorporation of [3H]thymidine into the acid-insoluble fraction of the cells in a dose-dependent manner. However, other heavy metals including zinc, copper, manganese and nickel did not show such a stimulatory effect. Stimulation of [3H]thymidine incorporation by basic fibroblast growth factor was additive to that by lead. However, stimulation by either platelet-derived growth factor or acidic fibroblast growth factor was reduced by the metal. The leakage of lactate dehydrogenase into the medium from smooth-muscle cells, a marker of cell death, was not changed by the metal. Calcium ionophore A23187 inhibited [3H]thymidine incorporation in vascular endothelial cells but stimulated it in vascular smooth-muscle cells. These results suggest that lead may stimulate the proliferation of cultured vascular smooth-muscle cells probably via a calcium-dependent pathway; the metal may mimic calcium within the cells.

Oral administration of clotrimazole and blockade of human erythrocyte Ca(++)-activated K+ channel: the imidazole ring is not required for inhibitory activity

The Ca(++)-activated K+ (Gardos) channel of erythrocytes plays a crucial role in K+ loss and dehydration of sickle erythrocytes; a potential therapeutic strategy would be to prevent dehydration by specifically blocking this channel. The authors report here on the activity of the clotrimazole (CLT) metabolite, 2-chlorophenyl-bis-phenyl-methanol, which accounts for a portion of the blockade of the erythrocyte Gardos channel when CLT is given orally to normal volunteers. Administration of a single oral dose of 1 g of CLT to four normal healthy volunteers (approximately 15 mg/kg of body weight) resulted in 51% to 92% peak inhibition of the Gardos channel measured in whole blood 2 to 4 hr later. Inhibition remained detectable for 24 to 34 hr. Inhibition of the Gardos channel correlated best with the summed levels of CLT plus its two major metabolites (P < .002; apparent IC50 = 0.65 +/- 0.19 microM). In vitro experiments with 2-chlorophenyl-bis-phenyl-methanol revealed dose-dependent inhibition of K transport and displacement of specifically bound 125I-charybdotoxin. Thus, the imidazole ring of CLT, which is required for antimycotic activity and associated with most of the historically observed toxicity, is not necessary for inhibition of the Gardos channel.

CT diagnosis of early hepatocellular carcinoma: sensitivity, findings, and CT-pathologic correlation

OBJECTIVE

The purpose of this study was to determine the sensitivity of CT in detecting early hepatocellular carcinoma and to evaluate its CT appearance. An early hepatocellular carcinoma is a nodular lesion with no fibrous capsule composed of well-differentiated tumor histologically. It differs from a small hepatocellular carcinoma, which is an overt tumor that is moderately to poorly differentiated and has a fibrous capsule. Size is not a criterion for distinguishing between early and small hepatocellular carcinomas.

MATERIALS AND METHODS

Thirty-one patients with 39 histopathologically proved early hepatocellular carcinomas (mean diameter, 1.7 cm) found by sonography, MR imaging, and/or intraoperative sonography were included in a retrospective study. We reviewed unenhanced CT scans of the entire liver in 30 patients (37 lesions) and early and late (35 sec and 5 min after the beginning of injection of contrast material) contrast-enhanced CT scans of the entire liver in all 31 patients (table incremental CT in 21; helical CT in 10; 39 lesions). Eighteen histologically proved small hepatocellular carcinomas (< or = 3 cm; mean diameter, 2.3 cm), present in the same patients, served for comparison. Histopathologically, nine patients had chronic hepatitis, and 22 had cirrhosis.

RESULTS

The overall sensitivity of CT in detecting early hepatocellular carcinoma was 56%. These tumors were usually isodense with respect to surrounding liver on unenhanced, early enhanced, and late enhanced CT scans (iso-iso-iso). This pattern was seen in 17 (46%) of 37 lesions; thus, these 17 histologically proved early hepatocellular carcinomas were not detected with CT. An iso-iso-low density pattern was recognized in eight (22%), a low-low-low pattern in seven (19%), and several different patterns in five (13%) of the 37 lesions. Only two (5%) of 39 early hepatocellular carcinomas had a high-density appearance on early enhanced CT scans. In comparison, the most common pattern of small overt hepatocellular carcinomas on CT scans was low-high-low, seen in 17 lesions (94%) detected with CT. When the density of lesions on unenhanced CT scans was compared with the histopathologic appearance of the masses, low-density lesions showed mild to moderate fatty change and isodense lesions showed no or minimal fatty change (p = .006).

CONCLUSION

The sensitivity of CT in detecting early hepatocellular carcinoma is poor (56%). However, the diagnosis of early hepatocellular carcinoma should be considered if CT scans show a small lesion with an iso-low or low-low density enhancement pattern on early and late contrast-enhanced CT scans, respectively, in patients with chronic liver disease.

Antioxidant effects of "beta catechin"

The free radical scavenging effect of "beta catechin", an antioxidant preparation containing green tea extract, ascorbic acid, sunflower seed extract, dunaliella carotene and natural vitamin E, was evaluated. Two techniques were used: electron spin resonance (ESR) spectrometry to measure radical-scavenging activity, and measurement of its effect on iron-induced lipid peroxidation in brain. A 0.05% solution of "beta catechin" completely scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (6.1 x 10(15)spins/ml). A 10% solution of "beta catechin" completely scavenged superoxide (4.2 x 10(15) spins/ml) generated by the hypoxanthine-xanthine oxidase system. An undiluted solution of "beta catechin" scavenged about 90% of hydroxyl radicals (3.5 x 10(15) spins/ml) generated by the Fenton reaction. "beta catechin"s effect on the accumulation of thiobarbituric acid-reactive substances (TBARS) was evaluated from tissue obtained from the ipsilateral cortex of FeCl3-induced epileptic rats. Oral administration of "beta catechin" (1 or 2ml/kg body weight) both inhibited TBARS formation and increased the activity of superoxide dismutase (SOD) in the ipsilateral cortex 30 min after iron-salt injection into the left sensory motor cortex. These data suggest that "beta catechin" has an antioxidant effect and may have a prophylactic effect against aging and other neurological diseases related to free radical mechanisms.

Cholangiocarcinoma arising in bile duct adenoma with focal area of bile duct hamartoma

A 59-year-old male with history of sigmoid colon cancer had a high serum-CEA level and was referred for the evaluation of metastatic liver disease. Ultrasonography and computerized tomography showed two tumours in the liver. Macroscopically, these were in segment 4 (S4) and 2 (S2). Histologically, the tumour in S4 showed a number of bile ductules with variable amounts of stroma, an appearance compatible with bile duct adenoma (BDA). There were markedly atypical ductules of various sizes, the epithelium of which had coarsely granular/hyperchromatic large nuclei, in some areas of the lesion. These atypical ductules showed invasive growth into the liver parenchyma. Some cystically dilated ductules with bile plugs resembling bile duct hamartoma (BDH) were also seen. The other tumour in S2, was a metastatic adenocarcinoma from sigmoid colon and showed strongly positive staining for CEA. Since the lesion in S4 of our case is solitary and most of histological features are similar to those of BDA with markedly atypical bile ductules, we consider that this may be the first case of cholangiocarcinoma associated with BDA with focal area of BDH. It is possible that the adenoma-carcinoma sequence occurs in biliary tumours.

HPLC measurement, blood distribution, and pharmacokinetics of oral clotrimazole, potentially useful antisickling agent

Clotrimazole (CLT) has recently been shown to be a potent and specific inhibitor of the Ca(2+)-activated K+ channel and to thereby prevent K+ loss and cellular dehydration of sickled erythrocytes. This evidence suggests that oral CLT may be a useful new therapy for sickle cell disease. Here, we describe the development of an HPLC assay to measure CLT, a method we used to study the pharmacokinetics and transport of CLT in normal volunteers. The assay's linear range extended to 10 mumol/L; the detection limit was 0.1 mumol/L, analytical recovery 97.7%, and run-to-run imprecision (CV) &lt; 4.7%. In unaffected subjects, CLT concentration peaked within 6 h of oral administration and returned to close to baseline by 24 h. High-density lipoproteins appear to be the main carriers of this drug in both normo- and hypertriglyceridemic plasma. We conclude that the method described here is ideally suited for therapeutic monitoring of CLT concentrations.

HPLC measurement, blood distribution, and pharmacokinetics of oral clotrimazole, potentially useful antisickling agent

Clotrimazole (CLT) has recently been shown to be a potent and specific inhibitor of the Ca(2+)-activated K+ channel and to thereby prevent K+ loss and cellular dehydration of sickled erythrocytes. This evidence suggests that oral CLT may be a useful new therapy for sickle cell disease. Here, we describe the development of an HPLC assay to measure CLT, a method we used to study the pharmacokinetics and transport of CLT in normal volunteers. The assay's linear range extended to 10 mumol/L; the detection limit was 0.1 mumol/L, analytical recovery 97.7%, and run-to-run imprecision (CV) < 4.7%. In unaffected subjects, CLT concentration peaked within 6 h of oral administration and returned to close to baseline by 24 h. High-density lipoproteins appear to be the main carriers of this drug in both normo- and hypertriglyceridemic plasma. We conclude that the method described here is ideally suited for therapeutic monitoring of CLT concentrations.

Longitudinal investigation of epidemiologic feature of adenovirus infections in acute respiratory illnesses among children in Yamagata, Japan (1986-1991)

Using human embryonic fibroblast (HEF) and HEp-2 cell cultures, adenoviruses were isolated from 989 (3.7%) out of 26,793 pediatric patients with ARI in Yamagata, Japan from January, 1986 to December, 1991. All isolates were identified as types 1 (Ad1)-6 and no other serotypes were identified. Epidemiologic feature was different depending on the subgenus group. Ad1, 2, 5 and 6 (group C) were endemic and the infections occurred frequently in the summer season. Ad3 (group B) was epidemic in the autumn to winter season, although the virus was isolated every month in non-epidemic season. No seasonal distribution of Ad4 (group E) could be determined because the number of patients was limited. Neutralizing antibody positive ratio for group C were more than 40% at 1-2 years of age and almost 100% by 10 years of age but those for Ad3 (group B) were 40% by 10 years of age. The neutralizing antibodies for Ad4 (group E) or Ad7 (group B) became negative by 10 years of age. With group C infections, most cases were infants and young children less than 2 years of age, but Ad3 infections were older children with the peak at 4 and 5 years of age.

Postcentral neurons of alert monkeys activated by the contact of the hand with objects other than the monkey's own body

In the caudal postcentral finger region near or in the anterior bank of the intraparietal sulcus of alert monkeys, we found neurons that were activated selectively by the contact of the hand to certain common objects such as bottle brushes, acrylic plates, parts of the stabilized monkey's chair, etc. All of these neurons were not activated when the monkey's hand was contacted with the monkey's own body. We concluded that these neurons are concerned with the haptic discrimination of common objects with the selectivity to one of various material variables of objects, and that the process involves differentiation of the object from the animal's own body.

Intratumoral DNA heterogeneity of small hepatocellular carcinoma

BACKGROUND

Intratumoral DNA heterogeneity provides important information regarding biologic and clinical behavior. The purpose of this study was to evaluate the incidence of DNA heterogeneity in small hepatocellular carcinoma (HCC) nodules.

METHODS

The DNA content of 28 surgically resected small HCC nodules (< or = 3.0 cm) was measured using flow cytometry of fresh or frozen samples taken from different parts of each nodule with reference to the macroscopic features.

RESULTS

Of the 28 small HCC nodules, 14 (50.0%) had only DNA diploid stemline characteristics. Five nodules (17.9%) manifested DNA diploid and DNA aneuploidy within the same tumor. Of the remaining nine nodules (32.1%) that showed only DNA aneuploidy, two contained tumor tissues with apparently different DNA content. Thus, DNA heterogeneity was found in 7 (25.0%) of 28 nodules. DNA heterogeneity correlated well with macroscopic histologic features. All four early HCC were composed of only DNA diploid cells, whereas three of six nodule-in-nodule lesions were composed of DNA heterogeneous cells, in which the inner obviously cancerous nodule showed DNA aneuploidy and the outer well differentiated HCC portion demonstrated DNA diploid. Four of 18 overt HCC nodules showed DNA heterogeneity; 2 of these 4 nodules showed both diploid and aneuploid peaks, and the other 2 two showed different aneuploid peaks within the same nodule.

CONCLUSIONS

DNA heterogeneity correlating with macroscopic features is found frequently even in small HCC nodules. Therefore, multiple sampling based on macroscopic features is required for the accurate assessment of DNA ploidy, particularly when the information about DNA ploidy is used as a prognostic indicator.

Prognostic factors of vision in patients with Behçet disease

BACKGROUND

Behçet disease is a chronic, recurrent, inflammatory disorder characterized by the triad of oral and genital ulcers and ocular lesions. The etiology is unknown. Although many of these patients become blind, some have good vision all their life.

METHODS

To attain more accurate data on the prognosis of these patients, the authors studied 52 Japanese patients (101 eyes) seen at Kyushu University Hospital between 1980 and 1990. At the first visit, patients ranged in age from 21 to 61 years; at onset, they ranged in age from 17 to 55 years; and the disease duration at first visit was from 0 to 22 years. Thirty-five of the 101 eyes had a visual loss of more than five lines or the patients became blind. The authors divided the subjects into two groups--favorable group and unfavorable group. If an eye had more than five lines of visual loss or the patient became blind 3 years after the first visit, it was placed in the unfavorable group, and if not, it was classed in the favorable group. Thirty-two factors determined from clinical records were used to select statistically significant risk factors for visual loss, using univariate analysis and multivariate logistic regression analysis.

RESULTS

Univariate analysis showed the following four factors that were significantly different between favorable and unfavorable groups: sex, disease interval, other complications, and skin lesions (first year). Multivariate analysis showed that the following seven factors had mutually independent contributions to visual loss: skin lesions; arthritis; posterior attacks; other complications (experienced), including gastrointestinal, vascular, and central nervous system lesions; female sex; disease interval; and anterior attacks. The first four factors have effects of losing vision, whereas the others are related to vision retention.

CONCLUSION

The authors find that skin lesions, arthritis, posterior attacks, and other complications are linked to loss of vision, whereas female sex, disease interval, and anterior attacks are related to retention of vision.

[A case of sepsis due to Escherichia coli isolated from blood, transtracheal aspiration and urine]

We reported a 53-year-old female who was admitted due to partial loss of consciousness. She had been diagnosed as old pulmonary tuberculosis and diabetes mellitus. She was diagnosed as diabetic keto-acidosis on admission. We isolated Escherichia coli in the blood, transtracheal aspiration (TTA) and from the urine. We have experienced 6 cases where the same bacteria was isolated from the blood and TTA at the same time. In all 6 cases, we have found single bacteria in the blood and a few other bacteria in TTA. Blood culture is the most certain method to detect the origin of infectious diseases. But the compromised host, as in this case, has multifocal infections in many cases. In order to understand the pathological aspects of the infection, we must obtain many kinds of samples and as many as possible.

Analysis of the neurofibromatosis 2 gene in human breast and hepatocellular carcinomas

The neurofibromatosis 2 gene (NF2) mapped to chromosome 22q is a recently isolated tumor suppressor gene that participates in the tumorigenesis of cells of embryonic neural crest origin. The structural similarities between the NF2 product, merlin-schwannomin, and the band 4.1 family raise the possibility that merlin may participate in a wide range of cell activities, in which the cytoskeleton latticework has important roles to play. In order to examine the significance of NF2 in general carcinogenesis, comprehensive analyses of 68 cases of breast carcinoma, which shows frequent loss of heterozygosity at chromosome 22, and 48 hepatocellular carcinomas of different histological grade were performed. No mutation was detected by the polymerase chain reaction-single-strand conformation polymorphism method for six exons of NF2 in any of the cases examined, suggesting that NF2 may be less important in the tumorigenesis of breast and liver cancers than in that of cancers originating from the neural crest.