Association of Statin Use with Dementia Risk Among Older Adults in Japan: A Nested Case-Control Study Using the LIFE Study.

Background: Previous studies have shown a possible association between statin use and a decreased risk of dementia, but the association has not been sufficiently established, especially in the super-aging society of Japan. Objective: This study aimed to determine the association between statin use and the risk of dementia among Japanese participants aged> =65 years old. Methods: Data from the Longevity Improvement and Fair Evidence (LIFE) Study were utilized, including medical and long-term care (LTC) claim data from 17 municipalities between April 2014 and December 2020. A nested case-control study was conducted with one case matched to five controls based on age, sex, municipality, and year of cohort entry. We used a conditional logistic regression model to calculate the odds ratios (ORs) and 95% confidence intervals (95% CIs). Results: This study included 57,302 cases and 283,525 controls, with 59.7% of the participants being woman. After adjusting for potential confounders, statin use was associated with a lower risk of dementia (OR, 0.70; 95% CI: 0.68-0.73) and Alzheimer's disease (OR: 0.66; 95% CI: 0.63-0.69). Compared with non-users, the ORs of dementia were as follows: 1.42 (1.34-1.50) for 1-30 total standardized daily dose (TSDD), 0.91 (0.85-0.98) for 31-90 TSDD, 0.63 (0.58-0.69) for 91-180 TSDD, and 0.33 (0.31-0.36) for >180 TSDD in dose-analysis. Conclusions: Statin use is associated with a reduced risk of dementia and Alzheimer's disease among older Japanese adults. A low cumulative statin dose is associated with an increased risk of dementia, whereas a high cumulative statin dose is a protective factor against dementia.

Postdischarge functional outcomes in older patients with acute heart failure in Japan: the Longevity Improvement & Fair Evidence study.

BACKGROUND: The association between care needs level (CNL) at hospitalisation and postdischarge outcomes in older patients with acute heart failure (aHF) has been insufficiently investigated. METHODS: This population-based cohort study was conducted using health insurance claims and CNL data of the Longevity Improvement & Fair Evidence study. Patients aged ≥65 years, discharged after hospitalisation for aHF between April 2014 and March 2022, were identified. CNLs at hospitalisation were classified as no care needs (NCN), support level (SL) and CNL1, CNL2-3 and CNL4-5 based on total estimated daily care time as defined by national standard criteria, and varied on an ordinal scale between SL&CNL1 (low level) to CNL4-5 (fully dependent). The primary outcomes were changes in CNL and death 1 year after discharge, assessed by CNL at hospitalisation using Cox proportional hazard models. RESULTS: Of the 17 724 patients included, 7540 (42.5%), 4818 (27.2%), 3267 (18.4%) and 2099 (11.8%) had NCN, SL&CNL1, CNL2-3 and CNL4-5, respectively, at hospitalisation. One year after discharge, 4808 (27.1%), 3243 (18.3%), 2968 (16.7%), 2505 (14.1%) and 4200 (23.7%) patients had NCN, SL&CNL1, CNL2-3, CNL4-5 and death, respectively. Almost all patients' CNLs worsened after discharge. Compared to patients with NCN at hospitalisation, patients with SL&CNL1, CNL2-3 and CNL4-5 had an increased risk of all-cause death 1 year after discharge (hazard ratio [95% confidence interval]: 1.19 [1.09-1.31], 1.88 [1.71-2.06] and 2.56 [2.31-2.84], respectively). CONCLUSIONS: Older patients with aHF and high CNL at hospitalisation had a high risk of all-cause mortality in the year following discharge.

Statin use and risk of Parkinson's disease among older adults in Japan: a nested case-control study using the Longevity Improvement and Fair Evidence study.

The association between statin use and the risk of Parkinson's disease remains inconclusive, particularly in Japan's super-ageing society. This study aimed to investigate the potential association between statin use and the risk of Parkinson's disease among Japanese participants aged ≥65 years. We used data from the Longevity Improvement and Fair Evidence Study, which included medical and long-term care claim data from April 2014 to December 2020 across 17 municipalities. Using a nested case-control design, we matched one case to five controls based on age, sex, municipality and cohort entry year. A conditional logistic regression model was used to estimate the odds ratios with 95% confidence intervals. Among the 56 186 participants (9397 cases and 46 789 controls), 53.6% were women. The inverse association between statin use and Parkinson's disease risk was significant after adjusting for multiple variables (odds ratio: 0.61; 95% confidence interval: 0.56-0.66). Compared with non-users, the dose analysis revealed varying odds ratios: 1.30 (1.12-1.52) for 1-30 total standard daily doses, 0.77 (0.64-0.92) for 31-90 total standard daily doses, 0.62 (0.52-0.75) for 91-180 total standard daily doses and 0.30 (0.25-0.35) for >180 total standard daily doses. Statin use among older Japanese adults was associated with a decreased risk of Parkinson's disease. Notably, lower cumulative statin doses were associated with an elevated risk of Parkinson's disease, whereas higher cumulative doses exhibited protective effects against Parkinson's disease development.

Development of a Conversion Table Linking Functional Independence Measure Scores to International Classification of Functioning, Disability, and Health Qualifiers: Insights from a Survey of Healthcare Professionals.

In clinical practice, patient assessments rely on established scales. Integrating data from these scales into the International Classification of Functioning, Disability, and Health (ICF) framework has been suggested; however, a standardized approach is lacking. Herein, we tested a new approach to develop a conversion table translating clinical scale scores into ICF qualifiers based on a clinician survey. The survey queried rehabilitation professionals about which functional independence measure (FIM) item scores (1-7) corresponded to the ICF qualifiers (0-4). A total of 458 rehabilitation professionals participated. The survey findings indicated a general consensus on the equivalence of FIM scores with ICF qualifiers. The median value for each item remained consistent across all item groups. Specifically, FIM 1 had a median value of 4; FIM 2 and 3 both had median values of 3; FIM 4 and 5 both had median values of 2; FIM 6 had a median value of 1; and FIM 7 had a median value of 0. Despite limitations due to the irreconcilable differences between the frameworks of existing scales and the ICF, these results underline the ICF's potential to serve as a central hub for integrating clinical data from various scales.

Intestinal Bacteria Fluctuating in Early-Stage Colorectal Cancer Carcinogenesis are Associated with Diet in Healthy Adults.

This hospital-based, cross-sectional study aimed to explore the association between diet and fluctuating intestinal bacteria in early-stage colorectal cancer (CRC) (Atopobium parvulum, Actinomyces odontolyticus, Solobacterium moorei, and Bifidobacterium longum). Healthy participants (n = 212) who underwent total colonoscopy at National Cancer Center Hospital (Tokyo, Japan) were divided into two groups according to the relative abundance of bacteria in their feces: those in the top 25% of relative bacterial abundance as cases and the bottom 25% as controls. The participants were divided into three groups (low, medium, and high) according to their intake of food groups associated with CRC. Multivariable logistic regression analysis was conducted to estimate the association between dietary intake and higher relative abundance of bacteria. Dairy products were inversely associated with a higher relative abundance of A. parvulum, A. odontolyticus, and S. moorei, with odds ratios (high vs. low) and 95% confidence interval as follows: 0.16 (0.06-0.44), 0.25 (0.08-0.82), and 0.29 (0.11-0.78), respectively. Additionally, dietary fiber was inversely associated with a higher relative abundance of S.moorei (0.29 [0.11-0.78]). No association was observed between diet and B.longum. In conclusion, healthy adults with a higher intake of dairy products and fiber had lower odds of having a higher relative abundance of CRC-associated microbiota.

Association of anticholinergic drug exposure with the risk of dementia among older adults in Japan: The LIFE Study.

OBJECTIVES: Several studies have investigated that anticholinergic drugs cause cognitive impairment. However, the risk of dementia associated with anticholinergics has not been extensively investigated in the super-aging society of Japan. We conducted this study to assess the association between anticholinergic drugs and the risk of dementia in older adults in Japan. METHODS: This nested case-control study used data from the Longevity Improvement & Fair Evidence Study, which includes claim data in Japan from 2014 to 2020. We included 66,478 cases of diagnosed dementia and 328,919 matched controls aged ≥65 years, matched by age, sex, municipality, and cohort entry year. Primary exposure was the total cumulative anticholinergic drugs prescribed from cohort entry date to event date or matched index date, which was the total standardized daily doses for each patient, calculated by adding the total dose of different types of anticholinergic drugs in each prescription, divided by the World Health Organization-defined daily dose values. Odds ratios for dementia associated with cumulative exposure to anticholinergic drugs were calculated using conditional logistic regression adjusted for confounding variables. RESULTS: The mean (standard deviation) age at index date was 84.3 (6.9), and the percentage of women was 62.1%. From cohort entry date to event date or matched index date, 18.8% of the case patients and 13.7% of the controls were prescribed at least one anticholinergic drug. In the multivariable-adjusted model, individuals with anticholinergic drugs prescribed had significantly higher odds of being diagnosed with dementia (adjusted odds ratio, 1.50 [95% confidence interval, 1.47-1.54]). Among specific types of anticholinergic drugs, a significant increase in risk was observed with the use of antidepressants, antiparkinsonian drugs, antipsychotics, and bladder antimuscarinics in a fully multivariable-adjusted model. CONCLUSIONS: Several types of anticholinergic drugs used by older adults in Japan are associated with an increased risk of dementia. These findings suggest that the underlying risks should be considered alongside the benefits of prescribing anticholinergic drugs to this population.

Association of pneumococcal vaccination with cardiovascular diseases in older adults: The vaccine effectiveness, networking, and universal safety (VENUS) study.

The protective effect of the 23-valent pneumococcal polysaccharide vaccine (PPSV23) against cardiovascular disease has been investigated in the United States and Europe; however, its effect has not been fully established. This study aimed to investigate the protective effect of PPSV23 on cardiovascular events in adults aged ≥ 65 years. This population-based nested case-control study was conducted using the claims data and vaccine records between April 2015 and March 2020 from the Vaccine Effectiveness, Networking, and Universal Safety (VENUS) Study. PPSV23 vaccination was identified using vaccination records in each municipality. The primary outcome was acute myocardial infarction (AMI) or stroke. The adjusted odds ratios (aORs) with 95% confidence intervals (CIs) for PPSV23 vaccination were calculated using conditional logistic regression. Among 383,781 individuals aged ≥ 65 years, 5,356 and 25,730 individuals with AMI or stroke were matched with 26,753 and 128,397 event-free controls, respectively. Individuals who were PPSV23 vaccinated, compared with the unvaccinated individuals, had significantly lower odds of AMI or stroke events (aOR, 0.70 [95% CI, 0.62-0.80] and aOR, 0.81 [95% CI, 0.77-0.86], respectively). More recent PPSV23 vaccination was associated with lower odds ratios (AMI, aOR 0.55 [95% CI, 0.42-0.72] for 1-180 days and aOR 1.11 [95% CI, 0.84-1.47] for 720 days or longer; stroke, aOR 0.83 [95% CI, 0.74-0.93] for 1-180 days and aOR 0.90 [95% CI, 0.78-1.03] for 720 days or longer). Among Japanese older adults, individuals who were PPSV23 vaccinated, compared with unvaccinated individuals, had significantly lower odds of AMI or stroke events.

Cholesterol and breast cancer risk: a cohort study using health insurance claims and health checkup databases.

PURPOSE: This study aimed to investigate the association between serum cholesterol and triglyceride levels and breast cancer risk in Japanese women. METHODS: We retrospectively evaluated the association between the levels of low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) and the incidence of breast cancer in a cohort study by using the health insurance claims and health checkup data from a database provided by JMDC Inc. We included 956,390 women who were insured between April 2008 and June 2019, identified breast cancer cases by using validated definitions, and estimated the risk of breast cancer by using multivariable Cox proportional hazards regression models adjusted for potential confounders. RESULTS: During the 2,832,277 person-years observation period (median 2.4 years), 6284 participants were diagnosed with breast cancer. There was marginally significant association between LDL-C and breast cancer risk when comparing the highest and lowest quintiles and at the clinical cutoff values for diagnosing hyperlipidemia. HDL-C was not associated with breast cancer. However, when stratified by age groups (< 50 and ≥ 50), HDL-C was inversely associated with breast cancer risk in women over 50 years old. TG was not associated with breast cancer risk. CONCLUSION: In this population, there was a modest association of LDL-C at the clinical cutoff values for diagnosing hyperlipidemia (140 mg/mL), and there were no associations of HDL-C and TG with breast cancer risk.

The interaction effect between physical and cultural leisure activities on the subsequent decline of instrumental ADL: the Fujiwara-kyo study.

BACKGROUND: Maintenance of instrumental activities of daily living (IADL) and social role (SR) is crucial to keep independent life because the decline in SR and IADL was a significant predictor of dependence in basic ADL in later. The independent effect of physical and cultural leisure activities and their effect modification on the IADL remains unknown. METHODS: We prospectively observed 3241 elderly with intact IADL at baseline for 5 years. Higher level functional capacity such as IADL and SR was assessed using the Tokyo Metropolitan Institute of Gerontology Index of competence (TMIG index). RESULTS: The mean age of the participants was 72.3 years (standard deviation 5.1), and 46.9% were male, and 90.9% of them received a follow-up assessment. Of the participants, 10.4% developed an IADL decline. Engagement in leisure physical activity was associated with a significantly lower risk of IADL decline (adjusted risk ratio, 0.73; 95% confidence interval [CI], 0.60 to 0.89), and cultural leisure activity was also associated with lower risk of IADL decline (adjusted risk ratio, 0.77; 95% CI, 0.63 to 0.95) independent of potential confounders. We also found significant and positive interaction between physical and cultural leisure activities at risk for IADL decline (P = 0.024) and SR decline (P = 0.004). CONCLUSIONS: We found an independent association of physical and cultural leisure activities with a lower risk for functional decline in IADL and SR with positive interaction. Combined engagement in physical and cultural activities may effectively prevent from IADL decline and SR decline.

Bodily pain, social support, depression symptoms and stroke history are independently associated with sleep disturbance among the elderly: a cross-sectional analysis of the Fujiwara-kyo study.

OBJECTIVE: To investigate independent effects of various factors associated with sleep disturbance among community-dwelling elderly individuals. METHODS: We analyzed data obtained from 3732 individuals aged ≥65 years who responded to a self-administered questionnaire and participated in a structured interview which assessed the Pittsburgh Sleep Quality Index (PSQI), subjective bodily pain, the Jichi Medical School Social Support Scale, the Geriatric Depression Scale (GDS-15), health status, and demographic characteristics. Sleep disturbance was defined as a global PSQI score >5.5, which was used as a dependent variable in multiple logistic regression analysis to determine adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) of related factors. RESULTS: We identified a significant increase in the adjusted ORs for female (OR 1.56, 95 % CI 1.34-1.83), age ≥80 years (1.31, 1.01-1.69), history of stroke (1.44, 1.08-1.92), and a GDS-15 score ≥6 as compared to 0-2 (2.29, 1.86-2.81), with regard to sleep disturbance. Participants with severe or very severe bodily pain had the highest adjusted OR (3.00, 2.15-4.19), and those with very mild bodily pain also had a relatively high OR (1.30, 1.06-1.60), relative to those without subjective bodily pain. In addition, compared with participants with strong social support from spouse or family, those with weak social support had significantly increased adjusted ORs (1.21, 1.01-1.44, 1.44, 1.23-1.70, respectively). CONCLUSIONS: The present study indicates that sleeping disturbances among the elderly are closely associated with social support from a spouse and family. They are also associated with pain, even at stages in which subjective bodily pain is very mild.

High-grade fetal adenocarcinoma of the lung is a tumour with a fetal phenotype that shows diverse differentiation, including high-grade neuroendocrine carcinoma: a clinicopathological, immunohistochemical and mutational study of 20 cases.

AIMS: High-grade fetal adenocarcinoma (H-FLAC) is a rare variant of pulmonary adenocarcinoma; this study aims to elucidate its clinicopathological features and genetic abnormalities. METHODS AND RESULTS: Clinicopathological, immunohistochemical and mutational analyses were performed on 20 surgically resected lung cancers that showed H-FLAC histology in various proportions. These tumours predominantly occurred in elderly males and in 10 patients who were heavy smokers. Four cases were pure H-FLAC, and 16 cases were mixed H-FLAC, which were found to be combined with conventional-type adenocarcinoma (15 cases), large-cell neuroendocrine carcinoma (three cases), small-cell carcinoma (one case), enteric adenocarcinoma (two cases), choriocarcinoma (two cases), and a solid-clear cell pattern (seven cases). The fetal phenotype and diverse differentiation were supported by the immunoexpression of α-fetoprotein (95%), thyroid transcription factor-1 (TTF-1) (50%), neuroendocrine markers (30-45%), proneural markers (50-69%), and CDX2 (40%). Except for TTF-1 expression (pure H-FLACs, 0%; mixed H-FLACs, 63%), there were no significant differences in histological or immunohistochemical findings between pure and mixed H-FLACs. EGFR, KRAS, BRAF and PIK3CA mutations were identified in 20%, 0%, 0% and 7% of the tumours, respectively. CONCLUSIONS: Lung adenocarcinomas with H-FLAC features possess the potential for multidirectional differentiation, and are not strongly associated with known major driver gene mutations.

Health-related quality of life (HRQOL) decreases independently of chronic conditions and geriatric syndromes in older adults with diabetes: the Fujiwara-kyo Study.

BACKGROUND: Very few studies have investigated the association between diabetes and impaired health-related quality of life (HRQOL) in older adults, independent of chronic conditions and geriatric syndromes. METHODS: We conducted a self-administered questionnaire survey and structured interviews with 3946 people aged 65 years or older to obtain medical histories of diabetes, chronic conditions, and geriatric syndromes. Blood tests were performed to measure glycated hemoglobin (HbA1c) and plasma glucose levels. HRQOL was evaluated using the Medical Outcomes Study 36-Item Short-Form General Health Survey (SF-36), and multiple logistic regression analysis was used to calculate adjusted odds ratios and 95% CIs for low HRQOL. RESULTS: A total of 3521 participants had not received a physician diagnosis of diabetes. Of these, 2345 participants with an HbA1c less than 5.7% were defined as the referent group. As compared with the referent group, 1029 participants with an HbA1c of at least 5.7% but less than 6.5% showed no significant decrease in QOL on the SF-36 physical, mental, and role component summaries, after adjustment for chronic conditions, geriatric syndromes, and other potential confounders. However, 572 patients who had received a physician diagnosis of diabetes and/or had an HbA1c of 6.5% or higher had a significantly higher adjusted odds ratio (1.48; 95% CI, 1.18-1.84) for the low physical component summary. No significant differences in relation to glycemic control, treatment regimen, or diabetes duration were found in any of the 3 component summaries among the 425 participants who were undergoing diabetes treatment. CONCLUSIONS: Older Japanese adults with diabetes had decreased physical QOL, independent of chronic conditions and geriatric syndromes.

[Factors associated with activities of daily living (ADL) in independently living elderly persons in a community: a baseline examination of a large scale cohort study, Fujiwara-kyo study].

OBJECTIVES: To investigate factors associated with activities of daily living in independently living elderly persons in a community. SUBJECTS AND METHODS: The potential subjects were 4,472 individuals aged 65 years and older who voluntarily participated in a large cohort study, the Fujiwara-kyo study. We used self-administered questionnaires consisting of an activities of daily living (ADL) questionnaire with the Physical Fitness Test established by the Ministry of Education, Culture, Sports, Science and Technology (12 ADL items) to determine the index of higher-level physical independence, demographics, Geriatric Depression Scale, and so on. Mini-mental state examination, measurement of physical fitness, and blood tests were also carried out. A lower ADL level was defined as having a total score of the 12 ADL items (range, 12-36 points) that was below the first quartile of a total score for all the subjects. Factors associated with a low ADL level were examined by multiple logistic regression. RESULTS: A total of 4,198 remained as subjects for analysis. The male, female and 5-year-old groups showed significant differences in the median score of 12 ADL items between any two groups. The highest odds ratio among factors associated with lower ADL level by multiple logistic regression with mutually adjusted independent variables was 4.49 (95%CI: 2.82-7.17) in the groups of "very sharp pain" or "strong pain" during the last month. Low physical ability, self-awareness of limb weakness, a BMI of over 25, low physical activity, cerebrovascular disorder, depression, low cognitive function, unable "to see normally", unable "to hear someone", "muscle, bone and joint pain" were independently associated with lower ADL level. CONCLUSION: Multiple factors are associated with lower ADL level assessed on the basis of the 12 ADL items.

Clear cell papillary cystadenocarcinoma of the epididymis: a case report and immunohistochemistry of markers for renal cell carcinoma.

Neoplasms of the epididymis are uncommon, and malignant tumors are extremely rare. We report a case of clear cell papillary cystadenocarcinoma of the epididymis presenting with a long history of painless scrotal mass on the left side. Immunohistochemical markers for clear cell renal cell carcinoma (RCC) were examined to distinguish between clear cell papillary cystadenocarcinoma of the epididymis and metastatic clear cell renal cell carcinoma. The present case was positive for cytokeratin-7, PAX2, vinculin, vimentin and carbonic anhydrase IX. Expression of CD10 was focally observed. In contrast, no immunoreactivities for α-methylacyl-CoA racemase, RCC marker, glutathione S-transferase α or C-KIT were detected. The immunophenotypic profile of clear cell papillary cystadenocarcinoma of the epididymis closely resembles that of clear cell papillary RCC, although the immunohistochemical markers tested in this study are useful to make a differential diagnosis between clear cell papillary cystadenocarcinoma of the epididymis and metastatic clear cell RCC.

[A case of neuroendocrine carcinoma of esophagus with a remarkable response to chemo-radiotherapy].

A 69-year-old man visited our hospital with complaints of hoarseness and dysphagia. Computed tomography showed wall thickening in the middle thoracic esophagus, tracheal invasion, and para-aorta lymph node swelling. An esophagoscopy revealed an elevated lesion in the middle portion of the esophagus, which was pathologically diagnosed as neuroendocrine carcinoma, stage IV: T4N3M1. Two courses of concurrent chemoradiotherapy using cisplatin and etoposide were performed, followed by 4 courses of combined chemotherapy with carboplatin and etoposide. The patient showed clinical complete remission.

A case of hepatocellular carcinoma with bleeding gingival metastasis treated by transcatheter arterial embolization.

The patient was a terminally ill 80-year-old man with multiple lung metastases from hepatocellular carcinoma, that had developed following hepatitis-C virus-associated cirrhosis. He was admitted to our hospital with gingival bleeding, and we diagnosed gingival metastasis from hepatocellular carcinoma, based on histological examination. The bleeding could not be controlled, and the patient became dyspneic. After transcatheter arterial embolization, his bleeding was successfully controlled until his death due to respiratory failure. Transcatheter arterial embolization was a safe and effective treatment in our case.

Weaving hypothesis of cardiomyocyte sarcomeres: discovery of periodic broadening and narrowing of intercalated disk during volume-load change.

To investigate how cardiomyocytes change their length, echocardiographic and morphological studies were performed on rabbit hearts that were subjected to volume overload, overload removal, and repeated cycles of overload and overload removal. These conditions were created by arterio-venous fistula between the carotid artery and jugular vein, closure of the fistula, and cycles of repeatedly forming and closing fistula, respectively. After overload, hearts dilated and myocytes elongated. Intercalated disks repeatedly broadened and narrowed with a 2-day cycle, which continued for 8 weeks in many animals. The cycle consisted of shifts between five modes characterized by two interdigitation elongation-and-shortenings as follows: (I) flat with short ( approximately 1/4 to approximately 1/3 sarcomere long) interdigitations; (II) flat with long (one sarcomere long) interdigitations; (III) grooved with short interdigitations; (IV) grooved with long interdigitations; (V) flat with short interdigitations intermingled by sporadic long interdigitations; and return to (I). After overload removal, hearts contracted and myocytes shortened with similar 2-day broadening and narrowing cycle of intercalated disks, in which the five modes were reversed. Repeated overload and overload removal resulted in the repetition of myocyte elongation and shortening. We hypothesize that a single elongation-and-shortening event creates or disposes one sarcomere layer, and the two consecutive elongation-and-shortenings occur complementarily to each other so that the disks return to their original state after each cycle. Our hypothesis predicts that intercalated disks weave and unravel one sarcomere per myocyte per day.

Sebaceous epithelial-myoepithelial carcinoma of the salivary gland: clinicopathologic and immunohistochemical analysis of 6 cases of a new histologic variant.

Epithelial-myoepithelial carcinoma (EMC) of the salivary glands is an uncommon, low-grade malignant tumor. A recent report demonstrates sebaceous differentiation in this tumor even though its significance has never been documented as a precise histologic variant. Six cases of EMC exhibiting sebaceous differentiation (sebaceous EMC) of the parotid gland were analyzed for their clinicopathologic features and immunohistochemical characteristics. In addition, primary salivary sebaceous carcinomas were also examined for comparison. In our series, the incidence of sebaceous EMC was 0.2% among 3012 cases of parotid gland tumors and 14.3% of all EMC cases. The 6 patients comprised 2 men and 4 women, age ranging from 77 to 93 years (mean, 83.7 y). Neither cervical lymph node nor distant organ metastases were found in any cases of sebaceous EMC and no patients died of disease, though local recurrences developed in 1 patient. Conversely, cervical lymph node metastasis was detected in 2 of 3 patients with sebaceous carcinoma, 1 of whom died of disease at 12 months. Histologically, all 6 tumors had an area of sebaceous differentiation admixed with features of bilayered ductal structures typical of EMC. A component of sebaceous differentiation was distributed diffusely in 4 tumors and focally in 2. Cytologic atypia of sebaceous EMCs was lesser than that of sebaceous carcinomas. Immunohistochemically, putative myoepithelial markers such as alpha-smooth muscle actin, calponin, p63, cytokeratin 14, S-100 protein, and vimentin were highly expressed in sebaceous EMC. However, the expression of the latter 4 markers was also observed in primary sebaceous carcinomas, whereas these tumors were all negative for alpha-smooth muscle actin and calponin. Positive immunoreactivity for epithelial membrane antigen, adipophilin, and perilipin confirmed sebaceous differentiation in EMC. These results indicate that sebaceous EMC is a low-grade malignancy, similar to conventional EMC. Our data also suggest that immunohistochemical examination of specific myoepithelial markers is helpful in distinguishing sebaceous EMC from sebaceous carcinoma, which may occasionally be associated with an aggressive clinical course.

Intermittent short-duration exposure to low wall shear stress induces intimal thickening in arteries exposed to chronic high shear stress.

We sought to determine whether intermittent short-duration exposure to low wall shear stress could induce intimal thickening in arteries chronically exposed to high shear stress. An arteriovenous fistula (AVF) was created between the left common carotid artery and the corresponding external jugular vein in 20 Japanese white male rabbits. After 4 weeks, blood flow was increased 10-fold to 182 +/- 39 ml/min and shear stress was increased to 33.4 +/- 13 dyn/cm(2). The AVF was then occluded for 1 h by finger compression with an 85% reduction in carotid artery blood flow (27 +/- 7 ml/min) and a reduction in wall shear stress to 4.9 +/- 1.7 dyn/cm(2) (P < 0.0001). Release of finger compression restored flow to the AVF and high shear stress to the carotid artery. This procedure was repeated at weekly intervals with a cumulative total of 4 h of low shear stress exposure. Arteries exposed to intermittent low shear stress developed a layer of intimal thickening which consisted of 3-4 layers of smooth muscle cells lined with thin elastic fibers and medial hyperplasia. Control arteries exposed to 8 weeks of continuous high shear had no intimal thickening. Transient exposure to low shear stress upregulated TGF-beta1, MMP-2, -14, and TIMP-2 gene expression while MMP-9 expression was downregulated. We conclude that repeated, intermittent short-duration exposure to low shear stress in the setting of high flow and high shear stress can induce arterial intimal thickening. Short-duration alterations in hemodynamic forces can induce rapid vascular cell message expression, which may effect arterial remodeling. This experiment suggests that a threshold value of 5 dyn/cm(2) may be needed in order to initiate and sustain the intimal thickening response.

Arterial enlargement, tortuosity, and intimal thickening in response to sequential exposure to high and low wall shear stress.

We investigated the effects of sequential and prolonged exposure to high and low wall shear stress on arterial remodeling using a rabbit arteriovenous fistula (AVF) model. Blood flow was increased by approximately 17-fold to 20-fold when the AVF was open, and returned to normal when the AVF was occluded. Repeated opening and closing of the AVF resulted in sequential exposure of the artery to high and low wall shear stress. High flow and high wall shear stress induced arterial dilatation, elongation, and tortuosity, without intimal thickening. The common carotid artery was elongated 37% after 4 weeks of high flow, and was shortened 10% after 6 weeks of normal flow. Subsequent cycles of high flow induced less elongation, with less shortening after return to normal flow. Enlargement of the distal segment was more dramatic than in the proximal segment, despite exposure to the same volume of flow and the same initial high wall shear stress after creation of the AVF. The distal carotid segment enlarged more than did the proximal segment during each exposure to high flow. In segments of carotid artery exposed to low wall shear stress (<5 dynes/cm(2)) intimal thickening developed. These changes were maximal in the distal carotid segment, just before the AVF. Each cycle of low wall shear stress induced intimal thickening accompanied by medial hyperplasia. Intimal thickening was inhibited during periods of high flow when wall shear stress was high. Three cycles of flow alteration induced three layers of intimal thickening in the distal arterial segment, two layers of intimal thickening in the middle segment, and one layer of intimal thickening in the proximal segment. Long-term exposure to low wall shear stress induced severe intimal thickening and medial hyperplasia in different segments. Thus the response of the carotid artery afferent to an AVF varies along the length of the artery, with maximum enlargement, elongation, and tortuosity in the distal segment, just proximal to the AVF. Similarly, intimal thickening in response to low wall shear stress is maximal in the distal carotid artery. It appears that intimal thickening is related to local levels of low wall shear stress, and occurs when wall shear stress chronically falls to less than 5 dynes/cm(2).