Comparison of risk factors for SARS-CoV-2 infection among healthcare workers during Omicron and Delta dominance periods in Japan

BACKGROUND

The risk factors for coronavirus disease (COVID-19) among healthcare workers (HCWs) might have changed since the emergence of the highly immune evasive Omicron variant.

AIM

To compare the risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among HCWs during the Delta- and Omicron-predominant periods.

METHODS

Using data from repeated serosurveys among the staff of a medical research centre in Tokyo, two cohorts were established: Delta period cohort (N = 858) and Omicron period cohort (N = 652). The potential risk factors were assessed using a questionnaire. Acute/current or past SARS-CoV-2 infection was identified by polymerase chain reaction or anti-nucleocapsid antibody tests, respectively. Poisson regression was used to calculate the risk ratio (RR) of infection risk.

FINDINGS

The risk of SARS-CoV-2 infection during the early Omicron-predominant period was 3.4-fold higher than during the Delta-predominant period. Neither working in a COVID-19-related department nor having a higher degree of occupational exposure to SARS-CoV-2 was associated with an increased infection risk during both periods. During the Omicron-predominant period, infection risk was higher among those who spent ≥30 min in closed spaces, crowded spaces, and close-contact settings without wearing mask (≥3 times versus never: RR: 6.62; 95% confidence interval: 3.01-14.58), whereas no such association was found during the Delta period.

CONCLUSION

Occupational exposure to COVID-19-related work was not associated with the risk of SARS-CoV-2 infection in the Delta or Omicron period, whereas high-risk behaviours were associated with an increased infection risk during the Omicron period.

Colonoscopic features and malignant potential of sessile serrated adenomas: comparison with other serrated lesions and conventional adenomas

AIM

Sessile serrated adenomas/polyps (SSA/Ps) have been proposed as precursors of colorectal cancer. The aims of this investigation were to compare the endoscopic findings of SSA/Ps with those of other serrated lesions and to compare the histological findings of SSA/Ps with those of conventional adenomas.

METHOD

We retrospectively reviewed colonoscopy records at our institution from 1984 to 2013 and identified cases of endoscopically or surgically resected conventional adenomas and serrated lesions, including SSA/Ps, hyperplastic polyps (HPs) and traditional serrated adenomas (TSAs). The colonoscopic findings of SSA/Ps were compared with those of the other two serrated lesions and histological findings were compared among all groups of lesions.

RESULTS

There were 79 HPs in 68 patients, 77 SSA/Ps in 63 patients, 167 TSAs in 145 patients and 6324 conventional adenomas in 4129 patients. The inverted type and flat-elevated type were more frequent among SSA/Ps than among the other two types of serrated lesions. Magnifying colonoscopy revealed that a round and open pit pattern, expanded crypt openings and varicose microvascular vessels were more frequently observed among SSA/Ps than among the other types. The incidence of high-grade dysplasia or carcinoma among SSA/Ps (13.0%) was significantly higher than that among HPs (0%, P < 0.001) and equivalent to that among conventional adenomas (12.3%).

CONCLUSION

SSA/Ps have colonoscopic features distinct from those of HPs and TSAs. The malignant potential of SSA/Ps seems to be equal to that of conventional adenomas.

Soft Drugs VI. The Application of the Inactive Metabolite Approach for Design of Soft β-Blockers1?2

The "inactive metabolite approach" was used to design β-blockers. The acidic inactive metabolite of metoprolol [4-(2-hydroxy-3-isopropylamino) propoxyphenylacetic acid] was used as the lead compound. Its esters (alkyl and cycloalkyl) were found active in vivo while reverting quantitatively to the same inactive metabolite in plasma. The cyclohexyl ester showed the best activity, which was cardioselective, similar to the parent compound metoprolol. Although most esters had a plasma half-life of approximately 1 min, their activity (antagonism of isoproterenol induced increase in heart rate) following intravenous administration lasted 45-90 minutes, and the maximum β-blockade was observed at 45-60 minutes in both rats and dogs.

Prognostic relevance of the lymph node ratio in surgical patients with extrahepatic cholangiocarcinoma

AIM

Few studies have investigated the influence of the lymph node ratio (LNR), the ratio of the number of lymph nodes harboring metastatic cancer to the total number of lymph nodes removed, on the outcome after surgery for extrahepatic cholangiocarcinoma. This study was conducted to examine the prognostic impact of LNR in patients undergoing resection for extrahepatic cholangiocarcinoma.

PATIENTS AND METHODS

We retrospectively analyzed a total of 60 consecutive patients who underwent resection for extrahepatic cholangiocarcinoma. We focused on the LNR, which was classified as 0 in 34 patients, between 0 and 0.2 in 13 patients, and greater than 0.2 in 13 patients.

RESULTS

The overall five-year survival rates for patients with LNRs of 0, 0 to 0.2, and ≥0.2 were 44%, 10%, and 0%, respectively (p = 0.023). LNR was an independent predictive factor for estimated survival by both univariate (p = 0.016) and multivariate (p = 0.022) analyses including LNR, the sites of the primary tumors, and surgical margin as the variables. There were no statistically significant differences between patients who had less than 12 lymph nodes removed and those who had 12 or more lymph nodes removed (p = 0.484).

CONCLUSION

LNR was a powerful, independent predictor of estimated survival in patients undergoing surgical resection for extrahepatic cholangiocarcinoma. LNR should be considered when stratifying patients for future clinical trials.

Distinct patterns of brain activity evoked by histamine-induced itch reveal an association with itch intensity and disease severity in atopic dermatitis

BACKGROUND

Little is known about brain mechanisms supporting the experience of chronic puritus in disease states.

OBJECTIVES

To examine the difference in brain processing of histamine-induced itch in patients with active atopic dermatitis (AD) vs. healthy controls with the emerging technique of functional magnetic resonance imaging (fMRI) using arterial spin labelling (ASL).

METHODS

Itch was induced with histamine iontophoresis in eight patients with AD and seven healthy subjects.

RESULTS

We found significant differences in brain processing of histamine-induced itch between patients with AD and healthy subjects. Patients with AD exhibited bilateral activation of the anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), retrosplenial cingulate cortex and dorsolateral prefrontal cortex (DLPFC) as well as contralateral activation of the caudate nucleus and putamen. In contrast, healthy subjects activated the primary motor cortex, primary somatosensory cortex and superior parietal lobe. The PCC and precuneus exhibited significantly greater activity in patients vs. healthy subjects. A significant correlation between percentage changes of brain activation was noted in the activation of the ACC and contralateral insula and histamine-induced itch intensity as well as disease severity in patients with AD. In addition, an association was noted between DLPFC activity and disease severity.

CONCLUSIONS

Our results demonstrate that ASL fMRI is a promising technique to assess brain activity in chronic itch. Brain activity of acute itch in AD seems to differ from that in healthy subjects. Moreover, the activity in cortical areas involved in affect and emotion correlated to measures of disease severity.

Repetitive scratching and noxious heat do not inhibit histamine-induced itch in atopic dermatitis

BACKGROUND

Repetitive scratching is the most common behavioural response to itch in atopic dermatitis (AD). Patients with chronic itch often report that very hot showers inhibit itch. We recently reported that scratching and noxious heat stimuli inhibit histamine-induced itch in healthy subjects. However, no psychophysical studies have been performed in AD to assess the effects of repetitive heat pain stimuli and scratching on histamine-induced itch.

OBJECTIVES

To examine the effects of repetitive noxious heat and scratching on itch intensity in patients with AD using quantitative sensory testing devices.

METHODS

Itch was induced with histamine iontophoresis in 16 patients with AD in both lesional and nonlesional skin as well as in 10 healthy subjects. Repetitive noxious heat and scratching were applied 3 cm distal to the area of histamine iontophoresis. Subjects rated their perceived intensity of histamine-induced itch with a computerized visual analogue scale.

RESULTS

Our results demonstrate that repetitive noxious heat and scratching do not inhibit itch intensity in lesional and nonlesional AD skin but do so in healthy skin. Of note, both these stimuli increase itch intensity in lesional AD skin.

CONCLUSIONS

Our results strongly suggest that scratching and noxious thermal stimuli have a different effect upon histamine-induced itch perception in patients with AD when compared with healthy controls. This difference may be associated with both peripheral and central sensitization of nerve fibres in AD.

Even distribution of BK polyomavirus subtypes and subgroups in the Japanese Archipelago

BK polyomavirus (BKV) is ubiquitous among humans, infecting children asymptomatically and then persisting in renal tissue. BKV has four subtypes (I-IV) that can be identified by serological and genotyping methods. Subtypes I and IV are most prevalent in all countries examined to date. Based on nucleotide sequence variation, subtype I is further classified into four subgroups (Ia, Ib-1, Ib-2 and Ic), each of which have a close relationship to a particular human population. To clarify the relationships between BKV and human populations, we investigated the distribution patterns of BKV subtypes and subgroups in the modern Japanese population, which was formed from two distinct ethnic groups. Urine samples were collected from immunocompetent elderly patients in six regions along the Japanese Archipelago. The 287-bp VP1 region of the viral genome from these samples was amplified using the polymerase chain reaction. The amplified VP1 regions were sequenced and a neighbor-joining phylogenetic tree was reconstructed to classify the BKV isolates. We observed a similar pattern of subtype distribution throughout the Japanese Archipelago, with subtype I always detected at high rates (67-75%), followed by subtype IV (19-31%), with rare or no detection of subtypes II and III. Based on phylogenetic and single nucleotide polymorphism analyses, the subtype I isolates were divided into subgroups; the percentage of the Ic subgroup was high in all geographic regions (88-100%). These results suggest that BKV subtypes and subgroups are evenly distributed in the Japanese Archipelago. We discuss the implications of these findings for the relationships between BKV and human populations.

Diagnostic utility of brain-natriuretic peptide for left ventricular diastolic dysfunction in asymptomatic type 2 diabetic patients

AIM

Left ventricular (LV) diastolic dysfunction has been reported to be prevalent in diabetic subjects, but this recognition could often be missed. We evaluated prevalence of LV diastolic dysfunction and diagnostic utility of brain-natriuretic peptide (BNP) in asymptomatic patients with type 2 diabetes mellitus.

RESEARCH DESIGN AND METHODS

Plasma BNP levels and LV geometry and diastolic filling indices, including the ratio of peak early transmitral Doppler flow (E) over flow propagation velocity (Vp) measured by colour M-mode Doppler echocardiography, were analysed in 98 consecutive asymptomatic patients with type 2 diabetes mellitus and 51 age-matched controls.

RESULTS

The LV mass index and relative wall thickness were higher in diabetic groups than controls without any differences in LV systolic function. The frequency of diastolic dysfunction defined as E/Vp > or = 1.5 were 31% in diabetic groups and 15% in controls (chi(2) = 4.364, p = 0.037). By receiver-operating characteristic (ROC) curve analysis, a BNP cutoff value of 19.2 pg/ml in controls had a 53.1% positive predictive value (53.1%) and a high negative predictive value (94.4%) for E/Vp >/= 1.5, whereas a BNP cutoff value of 18.1 pg/ml in diabetic groups had a 61.8% positive and 97.3% negative predictive values.

CONCLUSIONS

The frequency of E/Vp > or = 1.5 was higher in asymptomatic diabetic patients, suggesting that LV diastolic dysfunction was prevalent. The plasma concentration of BNP could be used to depict LV diastolic dysfunction in such population.

Vitamin B6 deficiency augments endogenous oxalogenesis after intravenous l-hydroxyproline loading in rats

The effects of an intravenous hydroxyproline load on endogenous oxalogenesis were compared in rats fed a standard diet or a vitamin B6-deficient diet. Twelve male Wistar rats were randomized to two groups and were fed either a standard diet (control group) or a vitamin B6-deficient diet for 3 weeks. Then the animals were intravenously administered 100 mg (762.6 micromol)/ml hydroxyproline. In the control group, infusion of hydroxyproline increased the 5-h urinary oxalate and glycolate excretion above baseline to 0.27% (2.02 +/- 1.11 micromol) and 0.32% (2.43 +/- 1.60 micromol) of the administered dose (mol/mol), while it was respectively 2.01% (15.24 +/- 2.13 micromol) and 0.00% (-0.02 +/- 0.19 micromol) of the dose in the vitamin B6-deficient group. Therefore, vitamin B6 deficiency augmented endogenous synthesis of oxalate from hydroxyproline by 7.56-fold (15.24/2.02) compared with that in the control group. Urinary citrate excretion was significantly lower at baseline and all other times in the vitamin B6-deficient group compared with the control group. In conclusions, L-hydroxyproline loading augmented endogenous oxalogenesis in the vitamin B6-deficient group without causing hyperglycolic aciduria, and also led to significant hypocitraturia. These findings suggest that hydroxyproline is not metabolized to oxalate via glycolate, but rather via the 4-hydroxyglutamate to glyoxylate pathway (usually requiring vitamin B6-dependent enzymes) even in the presence of vitamin B6 deficiency.

Prevalence of hepatitis C virus infection in cases of B-cell lymphoma in Japan

AIMS

To determine the prevalence of hepatitis C virus (HCV) infection in B-cell lymphoma in Japan. HCV infection and type II (monoclonal IgM) cryoglobulinaemia (CG) may be involved in the pathogenesis of low-grade B-cell lymphoma (ML) in southern Europe.

METHODS AND RESULTS

Forty-five (11.3%) of 400 B-cell ML cases were HCV antibody (Ab) positive, which was significantly (P < 0.01) higher than the blood donors (2.5%). Among them, 28 diffuse large B-cell lymphoma (DLBCL) cases were included. In the primary sites, 10 (47.6%) of 21 splenic DLBCL and seven (23.3%) of 30 gastric DLBCL were HCV Ab positive, which were significantly (P < 0.05) higher than the myeloma cases (4.9%). HCV infection was rarely (4.2%) detected in 24 lymphoplasmacytic and salivary gland low-grade B-cell ML cases. Type II CG was detected in one myeloma case (3.5%) of 29 HCV+ B-cell ML. By real-time polymerase chain reaction, HCV RNA was detected in fresh tumour tissues of all 11 B-cell ML cases examined. Lymphoma cells were positive for the envelope HCV non-structural (NS)3 and envelope (E2) proteins in six of eight examined B-cell ML cases.

CONCLUSIONS

The rare incidence of type II CG is characteristic of Japanese HCV+ ML patients and may influence the low incidence of low-grade B-cell ML. HCV infection may play a role in lymphomagenesis of splenic and gastric DLBCL.

Changes in Helicobacter pylori status in patients with rheumatoid arthritis under non-steroidal anti-inflammatory drugs

BACKGROUND

The role of Helicobacter pylori infection in rheumatoid arthritis (RA) patients during treatment with non-steroidal anti-inflammatory drugs (NSAID) is still unclear.

METHODS

By means of endoscopy and biopsy, gastroduodenal lesions and H. pylori status were repeatedly examined in 88 RA patients at intervals ranging from 26 to 49 months. Histology and culture were applied to determine H. pylori status. Serial changes in gastroduodenal lesions and histologic score for mucosal atrophy were compared among groups classified by initial and second H. pylori status.

RESULTS

There were 28 patients with continuously positive H. pylori infection (CP group), 33 patients with continuously negative H. pylori infection (CN group), 7 patients in whom H. pylori status became negative (PN group), and 20 patients in whom H. pylori status could not be determined (UD group). Age, duration and species of NSAID, disease activity of RA, gastroprotective drugs applied and the prevalence of gastroduodenal mucosal lesions were not different among the groups at either the initial or the second examination. In the PN group, the score for mucosal atrophy at the second examination was significantly lower than at the initial examination, whereas no difference was found for the CP, CN and UD groups. Overall, histologic score for mucosal atrophy was higher in H. pylori-positive patients than in H. pylori-negative patients at both initial and second examination.

CONCLUSIONS

In RA patients using NSAIDs, H. pylori infection may not affect the course of gastroduodenal lesions and activity of RA, but the infection contributes to mucosal atrophy.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm

AIMS

Only a few reports on renal cell carcinoma with rhabdoid features have been published. This study was performed to investigate the clinicopathological characteristics of renal cell carcinomas with rhabdoid features.

METHODS AND RESULTS

Among 253 cases of renal cell carcinoma in adults, eight cases with rhabdoid features were detected. Rhabdoid areas ranged from 10% to 90% of each of the cases. Seven of the eight cases were TNM stage III or IV, and four of the eight cases died within 8 months of surgery. Immunohistochemically, the rhabdoid areas were positive for CAM 5.2 (4/8), AE1/AE3 (6/8), epithelial membrane antigen (6/8) and vimentin (8/8), and negative for myogenetic markers (0/8). The mean MIB-1 labelling index in the rhabdoid areas was higher than that in the definite carcinomatous areas. Ultrastructurally, perinuclear whorls of intermediate filaments were demonstrated in three of the eight cases using paraffin-embedded blocks.

CONCLUSIONS

The rhabdoid areas in renal cell carcinoma have histological, immunohistochemical and ultrastructural similarities to malignant rhabdoid tumours. Renal cell carcinoma with rhabdoid features is a highly aggressive neoplasm and its malignant behaviour may be due to the high cell-proliferative activity of the rhabdoid areas. Rhabdoid features in renal cell carcinoma may represent the endpoint of clonal evolution of renal cell carcinoma (especially in clear cell type cases).

Calponin and h-caldesmon expression in atypical fibroxanthoma and superficial leiomyosarcoma

To evaluate smooth muscle differentiation, myogenic markers [desmin, alpha-smooth muscle actin (SMA), and muscle-specific actin (HHF35)] have been widely used. Calponin and h-caldesmon, which are cytoskeleton-associated actin-binding proteins, have been reported to be more specific myogenic markers, especially since myofibroblasts express a small amount of h-caldesmon. Atypical fibroxanthoma (AFX) occurs in the sun-exposed skin of the elderly and follows a benign clinical course. Histologically, AFX, which is a pleomorphic spindle cell tumor and considered to be a superficial variant of malignant fibrous histiocytoma, also mimics leiomyosarcoma. AFX has been thought to differentiate along pathways with fibrohistiocytic and myofibroblastic phenotypes. AFX ( n=10), superficial leiomyosarcoma (S-LMS) ( n=17) and benign fibrous histiocytoma (BFH) ( n=17) were analyzed for myofibroblastic and smooth muscle differentiation immunohistochemically from the viewpoint of comparison. AFX and BFH showed immunoreactivities respectively for calponin (3/10, 11/17), desmin (3/10, 1/17), SMA (3/10, 13/17), and HHF35 (1/10, 5/17), but failed to express h-caldesmon (0/10, 0/17). S-LMS had a high immunoreactive rate of calponin (17/17), desmin (13/17), SMA (16/17), and HHF35 (16/17), while also expressing caldesmon (11/17). The results reveal that AFX and BFH have immunoreactivities for several myogenic markers, with myofibroblastic differentiation (calponin: +/-, h-caldesmon: -), but without the smooth muscle differentiation seen in S-LMS (calponin:+, h-caldesmon: +/-). In addition, calponin and h-caldesmon are considered to be useful markers for distinguishing AFX from S-LMS.

Clinicopathological prognostic factors in soft tissue leiomyosarcoma: a multivariate analysis

AIMS

Prognostic factors affecting survival in cases of leiomyosarcoma of soft parts were investigated in this study.

METHODS AND RESULTS

A retrospective study of 267 patients was carried out. This group comprised 142 females (53%) and 125 males (47%), whose ages ranged from 7 to 95 years (median 58 years). One hundred and five cases were superficially situated (arising from the skin or subcutis), while the remaining 162 cases were deeply situated (subfacial). Nineteen were cases of pleomorphic leiomyosarcoma where the diagnosis had been amended from malignant fibrous histiocytoma to leiomyosarcoma whilst under review. Of the 167 patients with follow-up data, 83 died of leiomyosarcoma. In univariate analysis, depth, tumour size (>or=50 mm), mitotic rate of >20 per 10 high-power fields (HPF), tumour necrosis of >50% and a high stage according to the most recent American Joint Committee on Cancer (AJCC) staging for soft tissue sarcoma were found to lessen significantly the rate of survival (log rank test; P < 0.05). However, in multivariate analysis (Cox's proportional hazards model), tumour size and high AJCC stage were the only factors that were correlated independently with decreased survival.

CONCLUSIONS

This study indicates that the most reliable prognostic parameters are tumour size and AJCC stage in leiomyosarcoma.

CD3- bone marrow cells augment the generation of cytotoxic T lymphocytes showing a preference for the X-chromosome linked gene product of stimulator cells

Responder cells, composed of both a limited number of nylon wool-passed lymph node (NW-LN) cells and an excess number of CD3+ cell-depleted bone marrow (CD3- BM) cells from the same strain of mice, were stimulated with allogeneic spleen cells in vitro. The CD3- BM cells augmented the generation of allogeneic major histocompatibility complex (MHC) class I specific cytotoxic T lymphocytes (CTL) from NW-LN cells. C3H/He (H-2k, C3H background) responder cells were stimulated with either B10.D2 (H-2d, B10 background) or BALB/c (H-2d, BALB background) spleen cells. In the former stimulation, the CTL induced lysed B10.D2 target cells more efficiently than the BALB/c cells. Furthermore, these CTL lysed more (B10.D2 x BALB/c) F1 male target cells than (BALB/c x B10.D2) F1 male. In the latter stimulation, the CTL lysed more BALB/c than B10.D2 cells, and more (BALB/c) x B10.D2) F1 male than (B10.D2 x BALB/c) F1 male. The reciprocal mixed lymphocyte cultures (MLC) were carried out, in which BALB/c responder cells were stimulated with either C3H/He or B10.BR (H-2k, B10 background) spleen cells. In the former stimulation, the CTL induced lysed more C3H/He or (C3H/He x B10.BR) F1 male target cells than B10.BR or (B10.BR x C3H/He) F1 male, and in the latter, the reciprocal results were obtained. These results suggested that the CTL induced had a preference for the X-chromosome linked gene products (Xlgp), besides the specificity for the allogeneic MHC class I, of the mice used as stimulator.

Morphological transformation of Syrian hamster embryo cells at pH 6.7 by bemitradine, a nongenotoxic carcinogen

Bemitradine is a compound that was intended for use as a diuretic antihypertensive drug. In the preclinical safety assays, it was found to be nongenotoxic in five in vitro assays (Ames, mouse lymphoma, CHO/HGPRT, CHO chromosome aberration, and UDS) and in one in vivo assay (mouse bone marrow micronucleus). In a subsequent long-term bioassay using Sprague-Dawley rats, this compound was found to be a rodent carcinogen at multiple sites. Because of the carcinogenicity, further development of this compound as a drug was halted. Because the Syrian hamster embryo (SHE) cell transformation assay at pH 6.7 has been demonstrated to be a good predictor of carcinogenic activity in animals, this nongenotoxic compound was used to determine if this in vitro assay system could be utilized to predict the potential for the carcinogenicity in rodents. The SHE cell transformation assay was validated initially for use in this laboratory using genotoxic and nongenotoxic carcinogens including benzo(a)pyrene, 20-methylcholanthrene, 2-acetylaminofluorene, methapyrilene, and phenobarbital. Each of these chemicals induced a statistically significant increase in morphological transformation frequency. Bemitradine was initially tested in a range-finding cytotoxicity assay at 10-250 microg/mL for treatment periods of 7 days. Doses used in the 7-day treatment transformation assay were 1.25, 2.5, 5.0, 7.5, and 10.0 microg/mL. Statistically significant increases in morphological transformation frequencies were observed at 1.25, 2.5, and 7.5 microg/mL, indicating a positive response. The experiment was repeated with similar results confirming the previous conclusion. These data provide additional evidence that the pH 6.7 SHE cell transformation assay may be a valuable in vitro tool to detect nongenotoxic rodent carcinogens.

Antidepressant-like responses to the combined sigma and 5-HT1A receptor agonist OPC-14523

The antidepressant-like activity of a novel compound, OPC-14523, was investigated in comparison with the conventional antidepressants, fluoxetine and imipramine. OPC-14523 bound with nanomolar affinities to sigma receptors (IC(50)=47-56 nM), the 5-HT(1A) receptor (IC(50)=2.3 nM), and the 5-HT transporter (IC(50)=80 nM). OPC-14523 inhibited the in vitro reuptake of 3H-5-HT (IC(50)=27 nM), but it showed very weak inhibitory activity on 3H-NE and 3H-DA reuptake. OPC-14523 did not inhibit MAO A or B activities or muscarinic receptors. A single oral administration of OPC-14523 produced a marked antidepressant-like effect in the forced swimming test (FST) with rats (ED(50)=27 mg/kg) and mice (ED(50)=20mg/kg) without affecting the general locomotor activity. In contrast, fluoxetine and imipramine each required at least four days of repeated dosing to show this activity. The acute activity of OPC-14523 was blocked by pretreatment with the sigma receptor antagonist NE-100 or the selective 5-HT(1A) receptor antagonist WAY-100635. The induction of flat body posture by OPC-14523 was blocked by the selective 5-HT(1A) receptor antagonist NAN-190, and forebrain 5-HT biosynthesis was attenuated by OPC-14523 at behaviorally effective doses. In contrast, OPC-14523, unlike fluoxetine, failed to inhibit 5-HT reuptake at oral doses below 100mg/kg. Thus, the acute antidepressant-like action of OPC-14523 is achieved by the combined stimulation of sigma and 5-HT(1A) receptors without inhibition of 5-HT reuptake in vivo.

Immunoexpression of neurofibromin, S-100 protein, and leu-7 and mutation analysis of the NF1 gene at codon 1423 in osteofibrous dysplasia

The NF1 (neurofibromatosis type 1, or von Recklinghausen disease) gene, is a tumor-suppressor gene, and its product, neurofibromin, down-regulates ras protein by its guanosine triphosphatase-activating protein (GAP)-related domain. Osteofibrous dysplasia (OFD) is characterized by fibroblast-like spindle cells and osseous tissue and is generally seen in the tibia or fibula during childhood. The precise nature of OFD remains controversial. Cosegregations of OFD and NF1 have been reported, and it has been surmised that OFD is associated with the NF1 gene. We studied the expressions of NF1 gene product (neurofibromin) and so-called Schwann cell markers (S-100 protein, Leu-7) in 17 cases of OFD immunohistochemically. Ten cases of fibrous dysplasia (FD) were also used for the purpose of comparison. Five OFD and 7 FD cases were analyzed for NF1 gene mutation at codon 1423, which is a GAP-related domain, by single-strand conformation polymorphism. Fibroblast-like cells of OFD showed the expression of neurofibromin (5 of 17), S-100 protein (9 of 17), and Leu-7 (5 of 17), and those of FD did not show these expressions, with the exception of 1 case that showed Leu-7 expression. Regarding the OFD cases, significant correspondence was found between cases showing expression of neurofibromin and S-100 protein, between cases showing expression of neurofibromin and Leu-7, and between cases showing expression of S-100 protein and Leu-7 (P < .01). NF1 gene mutation at codon 1423 was not detected in either the OFD (0 of 5) or FD (0 of 7) cases. These results seem to suggest the possible involvement of neurofibromin in the development of OFD, which is associated with the expression of Schwann cell markers (S-100 protein and Leu-7). Furthermore, NF1 gene mutation at codon 1423 did not seem to be related to OFD.

Cilazapril prevents cardiac hypertrophy and postischemic myocardial dysfunction in hyperthyroid rats

We evaluated the effects of hyperthyroidism on cardiac structural changes and postischemic myocardial function, and also studied how an angiotensin-converting enzyme (ACE) inhibitor, cilazapril, can alter these changes. Hyperthyroidism was induced by daily intraperitoneal injection of thyroxine (T4) (600 microg/kg) with or without cilazapril (10 mg/kg per day, orally), and control rats were given by vehicle. After 2 weeks of treatment, T4-treated rats showed increases in blood pressure and heart weight to body weight ratio (HW:BW). Cilazapril decreased blood pressure to control values and reduced HW:BW. In the isolated working heart preparation, T4-treated rats showed a poor postischemic recovery of left ventricular pressure-rate product (14% of baseline at 30 minutes of reperfusion vs. vehicle 85%) and cardiac work (6% vs. 71%). Cilazapril recovered both values to 49% and 43%. Propranolol (500 mg/L in drinking water) decreased blood pressure to the same extent as cilazapril in hyperthyroid rats, but changed neither HW:BW nor the postischemic myocardial dysfunction. Percent recovery of cardiac work was inversely well correlated with HW:BW (R2 = 0.998, p < 0.001). Results indicate that T4-induced cardiac hypertrophy enhances postischemic cardiac dysfunction. Results also indicate renin-angiotensin system (RAS), but not sympathetic nerve activation, is involved in cardiac hypertrophy and postischemic myocardial dysfunction in hyperthyroid rats.

H-, K-, and N-ras gene mutation in atypical fibroxanthoma and malignant fibrous histiocytoma

Atypical fibroxanthoma (AFX) which is histologically similar to malignant fibrous histiocytoma (MFH), occurs in the sun-exposed skin. The presence of mutations at codons 12 and 13 of the H- and K-ras genes and in exons 1 and 2, which include codons 12, 13, and 61, of the N-ras gene was studied in 8 cases of AFX and 8 cases of storiform-pleomorphic-type MFH using polymerase chain reaction (PCR)-restriction fragment length polymorphism and PCR-single-conformation polymorphism. Two of the 8 cases of MFH showed ras mutations in the H-ras gene at codon 12 (GGC-AGC) and in the K-ras gene at codon 13 (GGC-GAC). H- and K-ras gene mutations were not seen in any of the cases of AFX (0 of 8). N-ras gene mutation was not detected in either the AFX (0 of 8) or MFH (0 of 8) cases. In conclusion, although the number of cases in this study was small, H- and K-ras genes were present in some of the MFH cases and accordingly may play an important role in the pathogenesis of MFH. In addition, the finding that H-, K-, and N-ras gene mutations are not present in AFX may indicate why AFX has a more favorable behavior than MFH.

Triiodothyronine concomitantly inhibits calcium overload and postischemic myocardial stunning in diabetic rats

Acute effects of triiodothyronine (T3) on postischemic myocardial stunning and intracellular Ca2+ contents were studied in the isolated working hearts of streptozotocin-induced diabetic rats and age-matched controls. After two weeks of diabetes, serum T3 and T4 levels were decreased to 62.5% and 33.9% of control values. Basal preischemic cardiac performance did not differ between diabetic and control rats. In contrast, during reperfusion after 20-min ischemia, diabetic rats exhibited an impaired recovery of heart rate (at 30-min reperfusion 57.5% of baseline vs. control 88.5%), left ventricular (LV) systolic pressure (44.1% vs. 89.5%), and cardiac work (23.1% vs. 66.0%). When 1 and 100 nM T3 was added before ischemia, heart rate was recovered to 77.2% and 81.8% of baseline, LV systolic pressure to 68.3% and 81.9%, and cardiac work to 50.8% and 59.0%, respectively. Diabetic rat hearts showed a higher Ca2+ content in the basal state and a further increase after reperfusion (4.96+/-1.17 vs. control 3.78+/-0.48 micromol/g, p<0.01). In diabetic hearts, H+ release was decreased after reperfusion (5.24+/-2.21 vs. 8.70+/-1.41 mmol/min/g, p<0.05). T3 administration caused a decrease in the postischemic Ca2+ accumulation (lnM T3 4.66+/-0.41 and 100 nM T3 3.58+/-0.36) and recovered the H+ release (lnM T3 16.2+/-3.9 and 100 nM T3 11.6+/-0.9). T3 did not alter myocardial O2 consumption. Results suggest that diabetic rat hearts are vulnerable to postischemic stunning, and T3 protects the myocardial stunning possibly via inhibiting Ca2+ overload.

Subcellular distribution of cytokeratin and vimentin in malignant rhabdoid tumor: three-dimensional imaging with confocal laser scanning microscopy and double immunofluorescence

Malignant rhabdoid tumor (MRT) is a highly aggressive neoplasm that mostly occurs in childhood, characterized histologically by rhabdoid cells as shown by eosinophilic intracytoplasmic inclusions. Although it is known that rhabdoid cells co-express cytokeratin (CK) and vimentin, the distribution patterns of these two kinds of intermediate filaments and structural relationship between them are still not known. We investigated the subcellular distribution of CKs 8 and 18 and vimentin in MRT cell lines (Tm87-16, STM91-01, TTC549, and TC289) using confocal laser scanning microscopy and double immunofluorescence, in addition to ultrastructural examination. Vimentin was diffusely expressed in the cytoplasm of MRT cells, focally forming a filamentous network. In contrast, CKs 8 and 18 were partially expressed in the cytoplasm of MRT cells, forming globules or a few vague agglomerates. Three-dimensional images in TC289 cells revealed distinct distribution patterns of cytokeratin and vimentin, showing agglomerates of cytokeratins within the vimentin filament network. We conclude that these globules and agglomerates of CKs 8 and 18 correspond with the characteristic ultrastructural finding, showing cytoplasmic bundles of intermediate filaments concentrated in whorled arrays.

Pleomorphic leiomyosarcoma: clinicopathologic and immunohistochemical study with special emphasis on its distinction from ordinary leiomyosarcoma and malignant fibrous histiocytoma

Pleomorphic leiomyosarcoma (PLMS) was recently described as a morphologic variant of leiomyosarcoma; however, its diagnostic criteria, as shown by morphologic features and biologic behavior, remain controversial. We describe 28 cases of pleomorphic sarcoma with pleomorphic areas in more than two thirds of the tumor and an ordinary leiomyosarcomatous fascicular area covering less than one third as PLMS. PLMS comprised 8.6% of all the leiomyosarcomas (322 cases) registered in our institute. Patients ranged in age from 31 to 89 years (average, 57.9 years). Seventeen patients (60.7%) were male and 11 were female. Tumor location was as follows: the extremities in 17 cases, the retroperitoneum or abdominal cavity in 7 cases, the chest/abdominal wall in 3 cases, and the scalp in 1 case. Histologically, all cases showed at least small foci of fascicles consisting of smooth muscle tumor cells, in addition to pleomorphic areas mimicking storiform-pleomorphic malignant fibrous histiocytoma. The border between pleomorphic and leiomyosarcomatous fascicular areas was sharp in 3 cases, gradual in 2 cases, and blending in 23 cases. Sixteen cases (57.1%) showed a typical storiform pattern, 6 cases revealed extensive stromal hyalinization, 6 cases showed a chronic inflammatory infiltrate, 2 cases had the foci of foamy xanthomatous cells, and 7 cases contained myxoid malignant fibrous histiocytoma-like areas covering less than 50% of the tumor. The tumors had a tendency to be of a morphologically higher grade (10 tumors were French Federation of Cancer Centers grade 2, 18 were grade 3). Five of 28 cases (18%) showed rhabdoid features. Immunohistochemically, all of the 28 tumors examined showed a positive reactivity for at least one smooth muscle marker (desmin, muscle-specific actin, and alpha-smooth muscle actin) in the leiomyosarcomatous fascicular areas. In the pleomorphic areas the expression of smooth muscle markers (desmin 10 of 28, muscle-specific actin 13 of 28, and alpha-smooth muscle actin 14 of 28) was significantly reduced, compared with that in leiomyosarcomatous fascicular area (desmin 18 of 28, muscle-specific actin 26 of 28, and alpha-smooth muscle actin 24 of 28). No significant difference was observed between the MIB-1 labeling index in the leiomyosarcomatous fascicular areas (26.10 on average) and that in the pleomorphic areas (26.17 on average). However, the MIB-1 labeling index in PLMS was significantly higher than that in ordinary leiomyosarcoma (n = 20, 12.86 on average) or storiform-pleomorphic malignant fibrous histiocytoma (n = 16, 16.63 on average). In 23 patients follow-up data were available with a duration of 1-239 months. Eleven patients developed metastases, and lung accounted for the most common site of metastasis (9 cases). Fifteen of 23 patients (65.2%) died of disease. Our results indicate that PLMS should be differentiated from ordinary leiomyosarcoma because of its high proliferative activities and rather aggressive biologic behavior.

Mutations of the p53 gene in malignant rhabdoid tumors of soft tissue and the kidney: immunohistochemical and DNA direct sequencing analysis

Malignant rhabdoid tumor (MRT) is characterized by the presence of intracytoplasmic eosinophilic inclusions composed of whorls of intermediate filaments. This tumor was originally described as an entity of the abortive type of Wilms' tumor in childhood. Recently, it has been proved that these rhabdoid cells can be observed in various types of malignant tumors, including soft tissue sarcoma or carcinoma. To investigate the oncogenesis of this tumor, we examined the p53 gene alteration by means of immunohistochemical analysis and DNA direct sequencing in three cases of malignant rhabdoid tumor (MRT) of the soft tissue and three cases of MRT of the kidney. All the cases of MRT of the soft tissue and two of the cases of MRT of the kidney showed immunopositivity for p53 protein. Among them, one of the cases of MRT of the soft tissue and two of the cases of MRT of the kidney showed missense mutations of the p53 gene. These results strongly suggest that p53 gene alterations may have an important role to play in the aggressive biological behavior and poor prognosis of this tumor.

Expression of intercellular adhesion molecules in epithelioid sarcoma and malignant rhabdoid tumor

We clinicopathologically evaluated 31 cases of epithelioid sarcoma (ES; 25 'classical' type and six 'proximal variant' type) and six cases of malignant rhabdoid tumor (MRT; three extrarenal and three renal). We also did immunohistochemical studies on 12 classical and three proximal variant cases of ES, and six cases of MRT, to clarify the differences in biological behavior in these tumors. E-cadherin, beta-catenin and CD34 expression was evaluated. We also carried out mutational analysis of exon 3 of the beta-catenin gene by polymerase chain reaction-single-strand conformation polymorphism analysis. In ES, the 5- and 10-year survival rates were 71.1 and 55.3%, respectively. A high mitotic rate (>15/10 high-power fields) was significantly correlated with a poor overall survival rate in ES (P = 0.0248). E-cadherin expression was observed in nine cases (69.2%) of ES and in four cases (66.7%) of MRT. Most of these tumors showed aberrant E-cadherin expression. Seven cases (46.7%) of ES were positive for CD34, although none of the cases of MRT were CD34 positive. Eleven cases (73.3%) of ES were positive for beta-catenin, which was localized to the cellular membrane, whereas all of the cases of MRT were beta-catenin negative. Mutational analysis for the beta-catenin gene was done in nine cases of ES and six cases of MRT, however, genetic alteration was not found. From our results, we conclude that beta-catenin membranous expression could be a useful marker for distinguishing ES, including the proximal variant, from MRT.

Immunoexpression of ultraviolet photoproducts and p53 mutation analysis in atypical fibroxanthoma and superficial malignant fibrous histiocytoma

p53 mutation is one of the major results of ultraviolet (UV) radiation. UV photoproducts of cyclobutane pyrimidine dimers (CPDs) and pyrimidine-pyrimidone (6-4) photoproducts (64PPs) also play an important role in skin cancer development. Atypical fibroxanthoma (AFX), which mimics malignant fibrous histiocytoma (MFH) histologically, occurs in the sun-exposed skin of the elderly, and therefore, an association with UV has long been suspected. Eighteen fibrohistiocytic skin lesions comprising AFX (n = 7), storiform-pleomorphic type MFH centered in the subcutis (superficial MFH; S-MFH; n = 4) and benign fibrous histiocytoma (BFH; n = 7) were used for immunohistochemical and molecular analysis. Eight cases of deep MFH (D-MFH) were also analyzed for UV photoproduct expression for the purposes of comparison. Immunohistochemically, the CPD scores of AFX (3.6 +/- 0.4) were significantly higher than those of S-MFH (1.3 +/- 0.8), D-MFH (0.8 +/- 0.5), or BHF (1.4 +/- 0.7); however, the 64PP scores were extremely low in all these tumors (AFX, 0.1 +/- 0.1; S-MFH, 0.0 +/- 0.0; D-MFH, 0.0 +/- 0.0; and BHF, 0.0 +/- 0.0). AFX, S-MFH, and BFH showed immunoexpression for p53 (2/7, 2/4, and 0/7), respectively. p53 mutations were detected in AFX (4/6; 67%) and S-MFH (1/4; 25%), but not in BFH (0/5; 0%) using polymerase chain reaction-single-strand conformation polymorphism, and all of the mutations in AFX were either C-T transitions or at dipyrimidine sites. In conclusion, AFX and S-MFH are both similar fibrohistocytic lesions; however, AFX has high immunoreactivity for CPDs compared with S-MFH, D-MFH, or BFH. These data suggest that CPDs may play an important role in the pathogenesis of AFX.

Micronucleus formation in mouse bone marrow cells in vivo in response to trans, trans-muconaldehyde

Benzene is a human leukemogen, and a bone marrow toxin and carcinogen in experimental animals. The reactive intermediates involved in benzene toxicity and their mechanism(s) of action have not been clearly delineated. We have investigated the clastogenic and cytotoxic effects of trans,trans-muconaldehyde (MUC), a reactive ring-opened benzene metabolite, in mouse bone marrow cells in vivo. Micronucleus formation was significantly increased when CD-1 mice were treated ip with MUC at 4 and 6 mg/kg/day for two days. These results suggest that leukemogenesis by benzene may be attributable, in part, to MUC-related clastogenic and cytotoxic effects in the bone marrow cells.