Patients with diabetes in pay-for-performance programs have better physician continuity of care and survival

OBJECTIVES

This study investigated the effects of physician continuity, measured as the Continuity of Care Index (COCI) score, on the survival of patients with diabetes, including both pay-for-performance (P4P) participants and nonparticipants.

STUDY DESIGN

This was a retrospective, nationwide population-based analysis of 396,838 patients with diabetes, with 198,419 subjects each in the P4P participant and nonparticipant groups, from 1997 to 2009, in Taiwan.

METHODS

The data presented in this study are secondary data obtained from the 1997 to 2009 National Health Insurance Research Database published by the Taiwan National Health Research Institute. Survival status and physician continuity were the dependent variables. Multiple regression analysis was used to examine the factors related to physician continuity among patients with diabetes. The Cox proportional hazard model was used to explore the related factors that affected the survival status of the patients with diabetes.

RESULTS

After controlling for the other related factors, the COCI score of the P4P participants was 0.227 higher than that of the nonparticipants (P <.05). Compared with patients with a low COCI score (≤50%), the hazard ratio (HR) of mortality of patients with a high COCI score (>50%) was 0.47 (95% confidence interval [CI], 0.46-0.48). Compared with nonparticipants, the HR of mortality of P4P participants was 0.43 (95% CI, 0.41-0.44).

CONCLUSIONS

Patients with diabetes with higher physician continuity had a lower HR of mortality. P4P participants had higher physician continuity and a lower HR of mortality.

A novel bioprinting method and system for forming hybrid tissue engineering constructs

Three dimensional (3D) bioprinting is a promising approach to form tissue engineering constructs (TECs) via positioning biomaterials, growth factors, and cells with controlled spatial distribution due to its layer-by-layer manufacturing nature. Hybrid TECs composed of relatively rigid porous scaffolds for structural and mechanical integrity and soft hydrogels for cell- and growth factor-loading have a tremendous potential to tissue regeneration under mechanical loading. However, despite excessive progress in the field, the current 3D bioprinting techniques and systems fall short in integration of such soft and rigid multifunctional components. Here we present a novel 3D hybrid bioprinting technology (Hybprinter) and its capability enabling integration of soft and rigid components for TECs. Hybprinter employs digital light processing-based stereolithography (DLP-SLA) and molten material extrusion techniques for soft and rigid materials, respectively. In this study, poly-ethylene glycol diacrylate (PEGDA) and poly-(ε-caprolactone) (PCL) were used as a model material for soft hydrogel and rigid scaffold, respectively. It was shown that geometrical accuracy, swelling ratio and mechanical properties of the hydrogel component can be tailored by DLP-SLA module. We have demonstrated the printability of variety of complex hybrid construct designs using Hybprinter technology and characterized the mechanical properties and functionality of such constructs. The compressive mechanical stiffness of a hybrid construct (90% hydrogel) was significantly higher than hydrogel itself (∼6 MPa versus 100 kPa). In addition, viability of cells incorporated within the bioprinted hybrid constructs was determined approximately 90%. Furthermore, a functionality of a hybrid construct composed of porous scaffold with an embedded hydrogel conduit was characterized for vascularized tissue engineering applications. High material diffusion and high cell viability in about 2.5 mm distance surrounding the conduit indicated that culture media effectively diffused through the conduit and fed the cells. The results suggest that the developed technology is potent to form functional TECs composed of rigid and soft biomaterials.

Biomechanical analysis of acromioclavicular joint dislocation treated with clavicle hook plates in different lengths

PURPOSE

Clavicle hook plates are frequently used in clinical orthopaedics to treat acromioclavicular joint dislocation. However, patients often exhibit acromion osteolysis and per-implant fracture after undergoing hook plate fixation. With the intent of avoiding future complications or fixation failure after clavicle hook plate fixation, we used finite element analysis (FEA) to investigate the biomechanics of clavicle hook plates of different materials and sizes when used in treating acromioclavicular joint dislocation.

METHODS

Using finite element analysis, this study constructed a model comprising four parts: clavicle, acromion, clavicle hook plate and screws, and used the model to simulate implanting different types of clavicle hook plates in patients with acromioclavicular joint dislocation. Then, the biomechanics of stainless steel and titanium alloy clavicle hook plates containing either six or eight screw holes were investigated.

RESULTS

The results indicated that using a longer clavicle hook plate decreased the stress value in the clavicle, and mitigated the force that clavicle hook plates exert on the acromion. Using a clavicle hook plate material characterized by a smaller Young's modulus caused a slight increase in the stress on the clavicle. However, the external force the material imposed on the acromion was less than the force exerted on the clavicle.

CONCLUSIONS

The findings of this study can serve as a reference to help orthopaedic surgeons select clavicle hook plates.

Effects of multidisciplinary team care on the survival of patients with different stages of non-small cell lung cancer: a national cohort study

In Taiwan, cancer is the top cause of death, and the mortality rate of lung cancer is the highest of all cancers. Some studies have demonstrated that multidisciplinary team (MDT) care can improve survival rates of non-small cell lung cancer (NSCLC) patients. However, no study has discussed the effect of MDT care on different stages of NSCLC. The target population for this study consisted of patients with NSCLC newly diagnosed in the 2005–2010 Cancer Registry. The data was linked with the 2002–2011 National Health Insurance Research Database and the 2005–2011 Cause of Death Statistics Database. The multivariate Cox proportional hazards model was used to explore whether the involvement of MDT care had an effect on survival. This study applied the propensity score as a control variable to reduce selection bias between patients with and without involvement of MDT care. The adjusted hazard ratio (HR) of death of MDT participants with stage III & IV NSCLC was significantly lower than that of MDT non-participants (adjusted HR = 0.87, 95% confidence interval = 0.84-0.90). This study revealed that MDT care are significantly associated with higher survival rate of patients with stage III and IV NSCLC, and thus MDT care should be used in the treatment of these patients.

Displacement of the distal radioulnar joint of clinically symptom-free patients

There are three methods for evaluation of dislocation of the distal radioulnar joint using computed tomography: the radioulnar line method, the epicenter method, and the congruity method. However, some patients who are clinically symptom-free have abnormal findings from computed tomography of the distal radioulnar joint according to the aforementioned criteria. In addition, these methods are qualitative, not quantitative definitions. Forty patients were included in this study. Computed tomography scans of the wrists were done. The variation of displacement of the distal radioulnar joint was measured. By the epicenter method, the 95% confidence interval (mean +/- 1.96 standard error) was from 0.0026 to 0.1114 in supination and from -0.1171 to 0.0446 in pronation. By the radioulnar line method, the 95% confidence interval was from 0.0026 to 0.0479 in supination and from -0.0065 to 0.0745 in pronation. By the modified radioulnar line method, the 95% confidence interval was from 0.1778 to 0.2752 in supination and from 0.0990 to 0.2310 in pronation. There was a wide range of the displacement of the distal radioulnar joint in patients with clinically normal wrists. The results can be regarded as reference points for normal variation of the distal radioulnar joint. This can help to differentiate the causes of internal derangement of the wrist.

Influence of 3D-CRT pelvic irradiation on outcome in prostate cancer treated with external beam radiotherapy

PURPOSE

The role of pelvic irradiation (PRT) in the treatment of prostate cancer remains unclear. We reviewed our institution's experience with three-dimensional conformal external beam radiotherapy (3D-CRT) during the prostate-specific antigen era to determine the influence of PRT on the risk of biochemical recurrence in patients who have a predicted risk of lymph node involvement.

METHODS AND MATERIALS

Between March 1985 and January 2001, 1832 patients with clinically localized prostate cancer were treated with definitive 3D-CRT. All treatments involved CT planning to ensure coverage of the intended targets. Treatment consisted of prostate-only treatment, prostate and seminal vesicle treatment, or PRT of lymph nodes at risk followed by a boost. To create relatively homogenous analysis groups, each patient's percentage of risk of lymph node (%rLN) involvement was assigned by matching the patient's T stage, Gleason score, and initial prostate-specific antigen level to the appropriate value as described in the updated Partin tables. Three categories of %rLN involvement were defined: low, 0-5%; intermediate, >5-15%; and high, >15%. Biochemical recurrence was defined as the first occurrence of either the American Society for Therapeutic Radiology and Oncology consensus definition of prostate-specific antigen failure or the initiation of salvage hormonal therapy for any reason.

RESULTS

The risk status (%rLN) could be determined for 709 low-risk, 263 intermediate-risk, and 309 high-risk patients. The actuarial freedom from biochemical recurrence (bNED) and the log-rank test for the similarity of the control and treatment survival functions are reported for each risk group. Multivariate analysis demonstrated a statistically significant benefit for the entire population treated with PRT, with a relative risk reduction of 0.72 (95% confidence interval 0.54-0.97). Although the multivariate analysis could not determine the patient population that would most benefit from PRT, the beneficial effect appeared to be most pronounced within the intermediate-risk group. Univariate analysis revealed that the intermediate-risk patients treated with PRT had an improved 2-year bNED rate, 90.1% vs. 80.6% (p = 0.02), and both low-risk and high-risk patients treated with PRT had statistically similar 2-year bNED rates compared with those who did not receive it.

CONCLUSION

Pelvic 3D-CRT appears to improve bNED in prostate cancer patients. Additional studies are needed to elucidate the %rLN population for which this treatment should be recommended.

Thymoma is associated with an increased risk of second malignancy

BACKGROUND

An association between thymoma and second malignancy has been suggested but has not been validated. Whether the relation is due to treatment or to other thymoma-associated conditions is unclear.

METHODS

The authors studied 192 consecutive patients with thymoma and compared the incidence of second malignancies with those of 206 patients who underwent thymectomy for nonthymomatous conditions and 1426 patients with nasopharyngeal carcinoma (NPC). Detailed clinicopathologic features of thymoma patients with second malignancies were described.

RESULTS

Additional malignancies were detected in 15 of 192 patients (8%) during their clinical courses. The risk for those patients was significantly greater compared with the risk for patients with nonthymomatous conditions (adjusted odds ratio [OR], 3.81; 95% confidential intervals [95%CI], 1.05-13.81; P = 0.042) and patients with NPC (adjusted OR, 4.89; 95%CI, 2.26-10.53; P < 0.0001) after adjustment for age, gender, length of follow-up, myasthenia gravis, and radiation therapy. The occurrence of second malignancies did not correlate with histologic type or stage of thymoma, radiation therapy, or myasthenia gravis.

CONCLUSIONS

Thymoma is associated with an increased risk of second malignancy. The association cannot be attributed to the effect of thymectomy or radiation therapy. Patients with thymoma, even if it is benign, should be followed regularly to facilitate the early detection of other malignancies.

High failure rate using allograft fascia lata in pubovaginal sling surgery for female stress urinary incontinence

OBJECTIVES

To present our unfavorable experiences using allograft fascia lata. Allograft fascia lata is an attractive sling material providing less pain, a shorter operation time, and a reported effectiveness equal to autologous fascia.

METHODS

A total of 18 women (mean age 51.7 years, range 37 to 76) underwent pubovaginal sling surgery for stress urinary incontinence between March 1999 and July 1999 and were enrolled in this study. Solvent dehydrated gamma-irradiated human fascia lata with a size of 7 x 2 cm was used as the sling. The results were collected with a questionnaire survey.

RESULTS

All patients were followed up for a mean of 9.2 months (range 6.9 to 11.6). Thirteen patients considered the surgery successful or to have provided improvement, with a mean of 82.5% (range 50% to 100%) subjective improvement. Five patients (27.8%) had significant failure with full recurrence of incontinence within 3 to 6 months.

CONCLUSIONS

Solvent dehydrated gamma-irradiated allograft fascia is not reliable in pubovaginal sling surgery. The high failure rates within a short period prohibit its use in the operative management of stress urinary incontinence.

Thymoma is associated with an increased risk of second malignancy

BACKGROUND

An association between thymoma and second malignancy has been suggested but has not been validated. Whether the relation is due to treatment or to other thymoma-associated conditions is unclear.

METHODS

The authors studied 192 consecutive patients with thymoma and compared the incidence of second malignancies with those of 206 patients who underwent thymectomy for nonthymomatous conditions and 1426 patients with nasopharyngeal carcinoma (NPC). Detailed clinicopathologic features of thymoma patients with second malignancies were described.

RESULTS

Additional malignancies were detected in 15 of 192 patients (8%) during their clinical courses. The risk for those patients was significantly greater compared with the risk for patients with nonthymomatous conditions (adjusted odds ratio [OR], 3.81; 95% confidential intervals [95%CI], 1.05-13.81; P = 0.042) and patients with NPC (adjusted OR, 4.89; 95%CI, 2.26-10.53; P < 0.0001) after adjustment for age, gender, length of follow-up, myasthenia gravis, and radiation therapy. The occurrence of second malignancies did not correlate with histologic type or stage of thymoma, radiation therapy, or myasthenia gravis.

CONCLUSIONS

Thymoma is associated with an increased risk of second malignancy. The association cannot be attributed to the effect of thymectomy or radiation therapy. Patients with thymoma, even if it is benign, should be followed regularly to facilitate the early detection of other malignancies.

Comparative analysis of sampling methods for grossing radical prostatectomy specimens performed for nonpalpable (stage T1c) prostatic adenocarcinoma

Scant data are available comparing sampling methods of radical prostatectomy specimens performed for clinical stage T1c (nonpalpable) cancer. Seventy-eight stage T1c radical prostatectomies that had 1 or more of the following adverse pathologic findings-Gleason score > or = 7, positive margins, and extraprostatic extension-were compared using 10 different sampling techniques. Of the 78 entirely submitted cases, 52 had Gleason score > or = 7, 14 had positive margins, and 54 had extraprostatic extension (mean 34 slides). Of the partial sampling methods, we favor the following two methods. The first is submitting every posterior section plus 1 midanterior section from right and left sides; if either of these anterior sections show sizeable tumor, all ipsilateral anterior slides are examined. This method detects 98% of tumors with Gleason score > or = 7, 100% of positive margins, and 96% of cases with extraprostatic extension (mean 27 slides). The second method is to use the above method but restrict it to sections ipsilateral to the previous positive needle biopsy. This method detects 92% of tumors with Gleason score > or = 7, 93% of positive margins, and 85% of cases with extraprostatic extension (mean 17 slides). Partial sampling can detect important prognostic parameters. By balancing the extra expense and time involved to process and examine additional sections with the risk of missing important prognostic parameters, pathologists can decide which sampling method to use.

Real-time dynamic telepathology through the Internet: evaluation of a new and economic technology at Taipei Veterans General Hospital

BACKGROUND

Computer-aided, digitalized telepathology was introduced about 10 years ago and is gaining acceptance as a mode of providing pathology to remote site. The usefulness of telepathology for remote diagnosis of histology, cytology and frozen section has been evaluated in USA, Europe and Japan. In Taiwan, the use of telepathology for pathological diagnosis is still rare. In order to evaluate the potential use of this technique, we undertook the study using commercialized and low-cost microscopy, personal computer and software on routine biopsy material.

METHODS

Sixty prostatic sextant transrectal needle biopsies, including 30 cases of adenocarcinoma and 30 cases of benign lesions, were retrieved retrospectively. The real-time dynamic images were transmitted to the remote site via internet and reviewed by a senior uropathologist who was unaware of the diagnosis. The diagnoses made at the remote site were correlated to the final diagnoses of the cases.

RESULTS

All malignant specimens (30/30) were correctly diagnosed by this method. Only one benign case (1/31) of nonspecific granulomatous prostatitis was misdiagnosed as poorly differentiated carcinoma.

CONCLUSIONS

Our results show that this method is a good way for teleconsultation. Further studies on other types of specimen worth encouragement for both intra- and inter-institutional consultation.

Expression of cyclooxygenase-2 in prostate adenocarcinoma and benign prostatic hyperplasia

Elevated expression of cyclo-oxygenase (COX)-2 has been found in several human cancers, including prostate adenocarcinoma. To evaluate the potential prognostic role of COX-2 in prostate cancer, we assessed the expression of COX-2 in benign prostatic hyperplasia (BPH) and prostate cancer samples employing immunohistochemistry. COX-2 was over-expressed in 15 out of 18 (83%) prostate cancer samples whereas it was detected in only 22% (4 of 18) paired benign tissues. The intensity of immunostaining correlated with the tumor grading. In addition, COX-2 was expressed in 7 of the 22 (32%) BPH samples examined. The significance a COX-2 expression in the BPH samples is not known at present. This data suggest that COX-2 is over-expressed in prostate cancer and COX-2 inhibitors may be useful in combination chemotherapy or chemoprevention for prostate cancer.

Spindle cell and mixed spindle/lymphocytic thymomas: an integrated clinicopathologic and immunohistochemical study of 81 cases

Forty-three cases of spindle cell thymoma (medullary, WHO type A) and 38 cases of mixed spindle/lymphocytic thymoma (WHO type AB) were studied for their clinicopathologic and immunohistochemical characteristics. Three histologic patterns of spindle cell thymoma were observed: short-spindled (57%), long-spindled (31%), and micronodular (12%). The short-spindled variant was composed of oval to short spindle cells commonly arranged in a hemangiopericytic or microcystic pattern. The long-spindled variant chiefly consisted of fibroblast-like epithelial cells mimicking fibrohistiocytic neoplasms. The micronodular variant was characterized by small nests of short spindle cells dispersed among a lymphoid stroma with frequent germinal centers. All kinds of spindle cell could be admixed with lymphocyte-rich "cortex"-like areas to constitute mixed spindle/lymphocytic thymomas. Immunohistochemically, the epithelial cells in up to 70% of the short-spindled and long-spindled variants of spindle cell thymoma and 90% of mixed spindle/lymphocytic thymomas were positive for CD20, whereas the epithelial cells in all micronodular spindle cell thymomas were negative. All of the spindle cell thymomas and most of the mixed spindle/lymphocytic thymomas in this study were found in stages I and II. Follow up of the patients did not disclose relapse or mortality directly resulting from the tumors. However, the prognosis of stage I and II spindle cell and mixed spindle/lymphocytic thymomas did not significantly differ from those of stage I and II thymomas of other types by a stage-matched survival analysis. Our data showed that spindle cell and mixed spindle/lymphocytic thymomas are distinctive in histologic pattern and immunohistochemical profile. When interpreted within the context of staging, spindle cell and mixed spindle/lymphocytic thymomas presenting in stages I and II most likely behave in an indolent fashion.

Tubulocystic clear cell adenocarcinoma arising within the prostate

Neoplasms resembling ovarian common epithelial-type tumors, including clear cell adenocarcinomas, rarely occur in the lower urinary tract of men. When they do, they develop in the urethra or urinary bladder. We report a case of such a tumor arising within the prostate of a 47-year-old man. The tumor was a cystic mass in the left posterolateral region of the prostate. Histologically, the tumor was chiefly composed of tubulocystic and papillary glands lined by glycogen-rich, cuboidal or hobnail cells with clear to eosinophilic cytoplasm. The tumor cells were strongly positive for pan-cytokeratin, low molecular weight cytokeratin, and epithelial membrane antigen, and focally positive for high molecular weight keratin. The tumor did not immunohistochemically express prostate-specific antigen (PSA) and prostatic acid phosphatase. Serologically, the patient had increased levels of CA125 instead of PSA. The clinical as well as the pathologic features are consistent with a clear cell adenocarcinoma as seen in the female genital tract rather than a typical prostatic adenocarcinoma.

The prognostic significance of tertiary Gleason patterns of higher grade in radical prostatectomy specimens: a proposal to modify the Gleason grading system

The Gleason grading system of prostatic adenocarcinoma does not account for the existence of a tertiary (third most prevalent) pattern, and there are no studies concerning the latter's prognostic influence. The authors analyzed 114 radical prostatectomies with small tertiary components, which mostly occupied less than 5% of whole tumors. These specimens were compared with a prostatectomy database comprised of 2,276 cases without a tertiary component. The pathologic stages of "typical" Gleason score 5 to 6 tumors (Gleason scores 2 + 3 = 5, 3 + 2 = 5, 3 + 3 = 6), which contained tertiary patterns 4 or 5, were significantly higher than those of "typical" Gleason score 5 to 6 tumors without pattern 4 (p = 0.018) but lower than those of "typical" Gleason score 7 tumors (p = 0.021; Gleason scores, 3 + 4 = 7, 4 + 3 = 7). Typical Gleason score 7 tumors with a tertiary pattern 5 showed significantly worse pathologic stages than typical Gleason score 7 tumors (p = 0.008) without pattern 5 and were not different statistically from typical Gleason score 8 (Gleason score, 4 + 4 = 8) tumors. Both typical Gleason score 5 to 6 and 7 tumors with tertiary components revealed significantly higher progression rates than typical Gleason score 5 to 6 tumors (p <0.0001) and Gleason score 7 tumors (p = 0.003) without tertiary components, and progressed like typical Gleason score 7 and 8 tumors respectively. Tertiary high-grade components have an adverse impact on biologic behavior. The authors propose that the Gleason system for radical prostatectomy specimens be modified to take into account small volumes of patterns 4 and 5, which are important prognostically.

Transitional cell carcinoma in dialysis patients

OBJECTIVE

The aim of our study was to determine whether there is an increased incidence of urothelial cancer, especially transitional cell carcinoma (TCC), in uremic patients on dialysis.

METHODS

Retrospective chart analyses were completed for 1,910 uremic patients undergoing maintenance dialysis between January 1987 and December 1997. The incidence of urinary tract cancer was assessed. Only the patients with cancers diagnosed after start of dialysis were enrolled in the study.

RESULTS

Of the 1,910 patients, 70 had concomitant urinary tract cancers. Nineteen patients (0.99%), including 17 patients with TCC and 2 patients with renal cell carcinoma, were diagnosed after the initiation of dialysis. The average duration from dialysis to TCC diagnosis was 38.3 (range 2-144) months. Painless gross hematuria was the cardinal symptom in 16 of the 17 patients with TCC. In the 17 patients with TCC, no distant metastases were found at the time of diagnosis. Fourteen patients (82.3%) were stage 0 or A, and 1 patient was stage B1.

CONCLUSIONS

The 0.89% incidence of TCC in our dialysis patients was high as compared with that of the general population. The risks of developing urinary TCC in dialysis patients were examined, and we suggest that immunosuppressive stage, dialysis procedure, and chronic bladder irritation (decreased urinary wash effect) may play a part in the development of urinary TCC in dialysis patients. Early detection of hematuria due to regular visits and decreased exposure of urinary tract epithelium to carcinogens from urine may explain why early-stage TCC was seen in most of our patients.

Evaluation and validation of ureteric jet index by glomerular filtration rate

RATIONALE AND OBJECTIVES

Ureteric jet index (UJI), a newly developed technique derived from color Doppler ultrasonography, may hold promise in evaluating renal function because of its ability to evaluate individual renal function and the use of nonionizing radiation. To assess the usefulness of UJI, the authors in this study analyzed the relation between UJI and the glomerular filtration rate (GFR).

METHODS

Fifteen adult patients with a wide range of renal function were included in this study. Subjects were well hydrated before color Doppler ultrasonography examinations. The UJI formula was: Vmean (average jet velocity) x D (jet duration) x F (jet frequency). GFR was calculated by the radionuclide method. Correlations between UJI, serum creatinine, and GFR were analyzed.

RESULTS

Ureteric jet index had only a fair correlation with GFR. The coefficient of correlation value was 0.61, and the standard error of estimate of GFR was 17.9 mL/min.

CONCLUSIONS

With the measurement of UJI, color Doppler ultrasound can provide both structural images and individual renal function information. It could substitute for a renal scan in determining individual renal function when a radionuclide examination is unavailable. Even if a renal scan were available, UJI can play a valuable role in the ultrasound examination of patients with suspected impaired renal function, providing further assessment of individual renal function.

Argyrophilic nucleolar organizer regions in cells of thymoma and thymic carcinoma: correlation with DNA ploidy and clinicopathologic characteristics

STUDY OBJECTIVES

To evaluate the usefulness of argyrophilic nucleolar organizer region (AgNOR) counting and flow cytometric DNA analysis in the differential diagnosis of thymoma and thymic carcinoma, as well as in the differences among various stages and histologic subtypes of these tumors.

DESIGN AND INTERVENTIONS

Paraffin-embedded blocks of 64 thymic epithelial tumors (20 noninvasive thymomas, 34 invasive thymomas, and 10 thymic carcinomas) were studied by AgNOR counting and flow cytometric DNA analysis. The thymomas were histologically classified as medullary, cortical, or mixed subtype.

MEASUREMENTS AND RESULTS

Invasive thymomas had more AgNORs (-/+ SD) than noninvasive thymomas (7.93+/-2.90 vs 5.97+/-1.77; p < 0.01). The number of AgNORs of thymoma increased progressively with advances in stage (p < 0.01). Cortical thymomas had the highest number of AgNORs among the three subtypes (p < 0.05). Patients with thymoma who presented with myasthenia gravis also had a higher number of AgNORs (8.30+/-3.12 vs 6.50+/-2.03; p < 0.01). The AgNOR number did not correlate with the DNA ploidy of all specimens.

CONCLUSIONS

AgNOR counting is useful in differentiating between invasive and noninvasive thymomas, and in predicting the stage of thymomas. A greater number of AgNORs was observed in patients with cortical thymoma and in those who presented with myasthenia gravis.

Iron-deficient diet reduces atherosclerotic lesions in apoE-deficient mice

BACKGROUND

Iron deposition is evident in human atherosclerotic lesions, suggesting that iron may play a role in the development of atherosclerosis. To test this idea, the correlation between the extent of iron deposition and the severity of atherosclerosis in apolipoprotein E (apoE)-deficient mice was investigated. Furthermore, the effect of a low-iron diet on the progression of atherosclerotic lesions in these animals was evaluated.

METHODS AND RESULTS

Iron deposition in tissues of apoE-deficient mice was examined by Perls' staining method. The results clearly demonstrated that iron deposits are present in atherosclerotic lesions and tissue sections of heart and liver in an age-dependent manner. When the young mice received a low-iron diet for 3 months, the hematocrit, serum iron, hemoglobin, and cholesterol concentrations were not significantly altered compared with those of littermates placed on a chow diet. However, the serum ferritin level of animals in the iron-restricted group was 27% to 30% lower than that of the control group in either sex. Furthermore, the lipoproteins isolated from the iron-restricted group exhibited greater resistance to copper-induced oxidation. Histological examination revealed that atherosclerotic lesions developed in mice fed a low-iron diet were significantly smaller than those found in control littermates. Likewise, the iron deposition as well as tissue iron content was much less in aortic tissues of the iron-restricted animals. Circulating autoantibodies to oxidized LDL and immunostains for epitopes of malondialdehyde-modified LDL detected on lesions were also significantly lower in mice fed a low-iron diet.

CONCLUSIONS

Iron deposition is closely associated with the progression of atherosclerosis in apoE-deficient mice. Restriction in dietary iron intake leads to significant inhibition of lesion formation in these animals. These results suggest that the beneficial effect of a low-iron diet may be mediated, at least in part, by the reduction of iron deposition as well as LDL oxidation in vascular lesions.

The role of interleukin 12 in the development of atherosclerosis in ApoE-deficient mice

The cytokine profile of atherosclerotic aortas from apoE-deficient mice was assessed by reverse transcriptase-polymerase chain reaction. The results clearly showed that the expression of mRNA for IL-12p40 was evident in aortas from 3-month-old apoE-deficient mice. The mRNA for IL-10 was detected in aorta from these mice at the age of 6 months, indicating that expression of IL-12 is earlier than that of IL-10 in these animals. Concurrent with IL-12p40, the mRNA for the T-cell cytokine IFN-gamma, but not IL-4, was detected in aortas of mice at young and old ages. Both in situ hybridization and immunostaining further demonstrated the localization of IL-12 in macrophages of atherosclerotic lesions. Immunohistochemistry also demonstrated the expression of costimulatory molecules B7-1 and B7-2 in macrophages, suggesting that activation of T lymphocytes by macrophages may occur via surface antigens in lesions. When the immunoglobulin isotype of the antioxidized LDL antibodies in sera of apoE-deficient mice was determined, it revealed that both IgM and IgG were present. Furthermore, IgG2a is predominant and comprises approximately 50% of the antioxidized LDL IgG in sera from young mice (3 months), but decreased to lower levels (35%) in older mice (6 months). Daily administration of IL-12 led to an increase in serum levels of antioxidized LDL antibodies and accelerated atherosclerosis in young apoE-deficient mice compared with control mice injected with PBS alone. Taken together, these data suggest that IL-12 plays an active role in regulating the immune response during the early phase of atherosclerosis in apoE-deficient mice.

Ki67 labelling index correlates with stage and histology but not significantly with prognosis in thymoma

AIMS

There have been several cell kinetic studies of thymoma, but the effectiveness of using Ki67 antibody as a tool to measure proliferative activity in this tumour was rarely evaluated. We carried out an immuno-histochemical study using this antibody to assess the clinicopathological correlation and the prognostic significance of this technique.

METHODS AND RESULTS

Ninety-one cases of thymoma were collected. Double immunostaining with Ki67 and cytokeratin KL-1 antibodies was performed on paraffin sections. Ki67 labelling index (LI) was expressed as a percentage of Ki67 immunopositive nuclei by counting at least 1000 epithelial cells. The LIs were correlated with stages, histological subtypes based on both Lattes-Bernatz and Müller-Hermelink-Kirchner classifications, and length of survival. There were statistically significant differences of LIs between stage I and stage III and between stage I and stage IV tumours. Histologically, statistically significant differences were identified between predominantly epithelial thymoma and every other subtype of the Lattes-Bernatz classification and between well-differentiated thymic carcinoma and medullary or mixed thymomas of the Müller-Hermelink-Kirchner classification. Regarding the prognostic implication of Ki67 LI, although there appeared a trend that patients with tumours of higher LIs had slightly worse survival, the difference was not statistically significant in both univariate and multivariate survival analyses.

CONCLUSIONS

We have demonstrated the proliferative potential in thymoma is associated with stage and histology. However, its clinical usefulness is limited on account of the overlap of LIs and lack of prognostic significance.

Colocalization of iron and ceroid in human atherosclerotic lesions

The presence of ceroid, a complex of protein associated with oxidized lipids, is commonly observed in human atherosclerotic lesions. When the human aortic walls were examined by Perls' staining, it was found that the iron deposits were evident in aortas with atherosclerosis. The extent of iron deposition was associated with the severity of the lesion. Furthermore, the iron deposits appeared to be colocalized with ceroids either extracellularly or intracellularly in foam cell-like macrophages or smooth muscle cells. Electron microscopy and X-ray microanalysis revealed that some of the extracellular iron aggregates were present within the ceroids. Likewise, some of the subcellular iron aggregates were found to be located near the lipid droplets or within the ceroids of foam cells. Collectively, these observations support the theory that the lipid oxidation occurring in lipid-laden cells of aortic lesions is facilitated by iron-overload in these cells.

Expression of E-cadherin and alpha- and beta-catenins in thymoma

Expression of the cell adhesion molecules including E-cadherin and its cytosolic binding proteins, alpha- and beta-catenins, has been widely studied in a variety of tumours, but not, to date, in thymic epithelial tumours. To observe the expression pattern of these adhesion molecules, immunohistochemical stains for E-cadherin (E-CD) and alpha- and beta-catenins were performed on 89 cases of thymoma which were classified as cortical (57 cases), mixed (18 cases), and medullary (14 cases), based on the classification of Marino and Müller-Hermelink. The majority of cortical thymomas showed diffuse and homogenous membrane immunoreactivity for these molecules (88 per cent for E-CD; 86 per cent for alpha-catenin; 91 per cent for beta-catenin) and the remaining cases showed heterogeneous immunoreactivity, whereas almost all mixed and medullary thymomas revealed decreased expression or were negative. In each histological subtype of thymoma, the expression did not correlate with invasion or with the presence of myasthenia gravis. These results indicate that the expression of E-CD and alpha- and beta-catenins is more closely associated with the histological subtypes of thymoma than with their biological behaviour.

Lower gastrointestinal bleeding from a hepatocellular carcinoma invading the colon

Bleeding from the gastrointestinal tract due to hepatocellular carcinoma invasion is unusual. We describe a 71-year-old man who had bloody stools caused by a hepatocellular carcinoma that directly invaded the transverse colon. The diagnosis was confirmed by colonoscopy and tissue examination. Our patient is the first with lower gastrointestinal bleeding from a hepatocellular carcinoma during the natural course of the tumor.

Signet-ring cell carcinoma of the rectum with tonsillar metastasis: a case report

A 36-year-old man was diagnosed as a case of mucinous adenocarcinoma of the rectum, Dukes' C. Pathologic examination revealed abundant signet-ring cells in the tumor. He did not receive adjuvant radiotherapy or chemotherapy after resection of the tumor. Two years later, a 3 x 5 cm mass over the right palatine tonsil was found with associated right neck lymphadenopathy. Right tonsillectomy was performed. Metastatic mucinous adenocarcinoma of the tonsil with abundant signet-ring cells similar to the primary tumor of the rectum was found. Signet-ring cell carcinoma of the rectum with tonsillar metastasis is extremely rare. No case has been reported in the English literature. To the best of our knowledge, this is the first case of signet-ring cell carcinoma of the rectum with tonsillar metastasis. The relevant literature on metastatic tonsillar tumors is reviewed.