Richter's syndrome: report of a case

A 42-year-old male presented with generalized massive lymphadenopathy, fever, weight loss and numerous cutaneous nodules. Peripheral blood examination showed lymphocytosis with small lymphocytes, and immunophenotyping revealed B-cell chronic lymphocytic leukemia (CLL). Cytogenetic analysis of bone marrow aspirate revealed a clonal abnormality of chromosome 11. Lymph node biopsies showed a B-immunoblastic lymphoma. A diagnosis of Richter's syndrome (RS) was made. The patient did not respond to doxorubicin, cyclophosphamide, vincristine and prednisolone (CHOP) and died of progressive disease with pneumonia and respiratory failure 9 months later. CLL is not common among Chinese people and RS is extremely rare.

Recurrence of Fusarium solani abscess formation in an otherwise healthy patient

Fusarium spp. are usually considered opportunistic fungi in humans. A case of Fusarium solani abscess formation of the foot in an immunocompetent patient in whom recurrence occurred even after intravenous amphotericin B treatment is presented here.

Clear cell papulosis: report of three cases of a newly recognized disease

BACKGROUND

Clear cell papulosis is a newly described disease. Since the first report in 1987, no other cases have been reported.

OBJECTIVE

Our purpose was to describe three more newly identified cases that further characterize this disease.

METHODS

Formalin-fixed and paraffin-embedded biopsy specimens were used for histochemical and immunohistochemical studies.

RESULTS

The three patients included two boys and, for the first time, a girl. All three had multiple white papules on the lower part of the abdomen, with or without scattered lesions along the milk lines bilaterally. The main histopathologic finding was the presence of clear cells scattered mainly among the basal cells of the acanthotic epidermis. The clear cells were variably stained by mucicarmine, colloidal iron, alcian blue (pH 2.5), periodic acid-Schiff, the anticytokeratin antibody AE1, carcinoembryonic antigen, epithelial membrane antigen, and gross cystic disease fluid protein-15.

CONCLUSION

Clear cell papulosis is a unique clinicopathologic entity. The clear cells were confirmed to be sweat gland secretory cells by their positive immunostaining with gross cystic disease fluid protein-15. The latter was also present in eccrine sweat gland coil cells. However, whether the clear cells were eccrine or apocrine secretory cells could not be determined.

Kimura's disease and angiolymphoid hyperplasia with eosinophilia: new observations from immunohistochemical studies of lymphocyte markers, endothelial antigens, and granulocyte proteins

Kimura's disease (KD) typically presents as large subcutaneous masses in young Oriental males. It is characterized by deep inflammation with vascular proliferation, lymphocytic nodules with subcutaneous germinal centers, fibrosis, and edema. In comparison, angiolymphoid hyperplasia with eosinophilia (AHLE) occurs in all races and the lesions usually are smaller and more superficial. The causes of these two diseases are debated. We compared histologic features of 4 cases of KD with 22 cases of ALHE and studied expression of endothelial antigens and lymphocyte markers as well as localization of eosinophil, mast cell, and neutrophil granule proteins in lesional tissue. T-cell lymphoid aggregates with well-formed B-cell germinal centers occurred in KD, and nodular and diffuse T-cell infiltration with small B-cell clusters occurred in ALHE. Endothelial proliferation was more pronounced in KD, lacking the atypical histiocytoid endothelial cells characteristic of ALHE. Many intact eosinophils infiltrated lesions in both diseases, although KD had less extracellular granule protein deposition than ALHE. Intact mast cells were seen in both diseases. There was neutrophil elastase staining of occasional scattered intact cells but no extracellular deposition. Compared with KD, ALHE is more varied in its clinical, histopathologic, and immunohistochemical features.

Kikuchi's disease (histiocytic necrotizing lymphadenitis). A clinicopathologic study of 79 cases with an analysis of histologic subtypes, immunohistology, and DNA ploidy

We conducted a clinicopathologic study of 79 cases of Kikuchi's disease. Our results confirmed that Kikuchi's disease is a distinctive type of necrotizing lymphadenitis that affects primarily the cervical lymph nodes of young adults and has a self-limited clinical course. However, female predominance was not as striking as heretofore reported. A low, but possible, recurrence rate of 3.3% was documented. Extranodal cutaneous involvement occurred in one patient who had a more severe and protracted clinical course. Classification of the histopathologic changes into three histologic types was proposed: proliferative, necrotizing, and xanthomatous types. These three types differed in certain aspects of their clinical features. Immunohistologic analysis revealed that the predominant cells of the lesions were various types of histiocytes, including the enigmatic plasmacytoid monocytes. A variable number of CD8(+) T cells correlating with the duration of the disease was detected. B cells were nearly absent, and only an insignificant number of OPD4(+) T cells was present. Eight cases studied by the flow cytometric DNA analysis all showed a diploid DNA content. Although the histologic changes of Kikuchi's disease were variable, the findings were sufficiently distinctive to permit accurate diagnosis. Malignant lymphoma and especially lupus lymphadenitis can be mistaken for Kikuchi's disease; thus differentiation is crucial.

Absence of p53 gene mutation and infrequent overexpression of p53 protein in hepatoblastoma

Ten cases of hepatoblastoma were studied for overexpression of p53 protein by immunohistochemistry and for possible p53 gene mutation by single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing of the polymerase chain reaction products. Only one case of the macrotrabecular type at stage IV showed overexpression of p53 protein. No DNA mobility shift was found in any of these cases studied by SSCP analysis. DNA sequencing performed on the case showing overexpression of p53 protein revealed no mutation within exons 5 to 8. The associated adrenal cortical carcinoma of the same case also showed overexpression of p53 protein, but no mutation of the p53 gene. These results indicate that mutation of the p53 gene is infrequent in hepatoblastoma. This observation supports the view that mutation of the p53 gene is not as important in the oncogenesis of childhood neoplasms as in adult cancers.

Characterization of an open reading frame involved in site-specific integration of filamentous phage Cf1t from Xanthomonas campestris pv. citri

Cf1t is a single-stranded DNA filamentous phage; a 1.9-kb segment of DNA from Cf1t was found to be responsible for site-specific integration into Xanthomonas campestris pv. citri (XW47), in the absence of any Xanthomonas origin of replication. Deletion analysis and introduction of amber stop codons into this fragment from Cf1t revealed an open reading frame (ORF344) which was involved in the integration function. The predicted amino-acid sequence of ORF344 bears no homology with conserved sequences of the integrase family.

Abnormal growth induced by expression of HBsAg in the secretion pathway of S. cerevisiae pep4 mutants

The toxicity of HBsAg in the secretion pathway of pep4 strains can be progressively reduced in modified SD media containing lower concentrations of ammonium sulphate. A procedure, combining a reduction of ammonium sulphate concentration in SD media with the disruption of the PEP4 gene of the host strain, was developed to enrich transformants which are not inhibited by HBsAg expressed in the secretion pathway. Abnormal growth of these non-inhibited transformants is characterized by the enlargement of cell morphology, a transition to pseudohyphal-like growth in nitrogen-starved media, an increase in HBsAg particle production, and the enhancement of growth rate in liquid media. This suggests a new approach to overcoming the toxicity of heterologous protein in the yeast secretion pathway.

Prolongation of intraventricular conduction time associated with fatal [correction of fetal] impairment of defibrillation efficiency during treatment with class I antiarrhythmic agents

To test whether fatal deterioration of defibrillation efficiency during antiarrhythmic therapy can be prevented by avoiding extreme decrease in ventricular prevented by avoiding extreme decrease in ventricular conduction or toxic plasma drug levels, we determined the defibrillation threshold (DFT) before and during infusion of incremental doses of disopyramide (n = 8), mexiletine (n = 9), or flecainide (n = 9) in anesthetized dogs. Disopyramide did not alter DFT [from 4.4 +/- 1.5 to 4.4 +/- 1.6 J (3.1 +/- 1.2 micrograms/ml)]. Mexiletine tended to increase DFT [from 4.6 +/- 1.2 to 6.1 +/- 2.0 J (1.8 +/- 0.6 micrograms/ml); p < 0.05], and defibrillation eventually was unsuccessful in 3 of the 9 dogs. Although the plasma mexiletine level before refractory fibrillation was far beyond the human therapeutic range, prolongation of intraventricular conduction time (CT) was moderate (16 +/- 3%). Flecainide increased DFT from 4.2 +/- 1.3 to 6.1 +/- 1.5 J at a plasma level of 1.04 +/- 0.37 micrograms/ml (p < 0.0005). In 3 of 5 dogs that developed refractory fibrillation, plasma flecainide level before terminal ventricular fibrillation (VF) was not toxic, but prolongation of CT in the 5 dogs was remarkable (30 +/- 9%). Thus, VF resistant to defibrillation is not necessarily associated with both toxic plasma drug level and remarkably decreased conduction. Reliability of these valuables as indicators of fatally deteriorated defibrillation efficiency may vary among antiarrhythmic agents.

Attenuation of antifibrillatory effects of lidocaine by its metabolite, glycylxylidide: application of modulated receptor hypothesis

Lidocaine, one of the drugs effective in treating ventricular arrhythmias in acute myocardial infarction (AMI), sometimes loses its efficacy after prolonged administration, possibly owing to the counteraction of glycylxylidide, one of the metabolites of lidocaine, through modulation of binding of lidocaine to sodium channels. To determine whether glycylxylidide interferes with the antiarrhythmic action of lidocaine, we compared the antifibrillatory effects of lidocaine, glycylxylidide, and their combination in 14 anesthetized open-chest dogs. Although glycylxylidide alone prolonged intraventricular conduction time (CT) and did not affect ventricular effective refractory period (VERP), it had different effects when added to lidocaine; i.e., it had no effect on intraventricular conduction time but shortened VERP. Although glycylxylidide alone did not change ventricular fibrillation threshold (VFT), the increase in VFT induced by lidocaine was decreased by addition of glycylxylidide, possibly as a result of competition for the same cardiac sodium channels between lidocaine and glycylxylidide with similar onset but different offset kinetics, which may explain, at least in part, the drug-resistance phenomena that ensue from prolonged lidocaine administration.

Immunohistochemical analysis of dermal mononuclear cell infiltrates in cutaneous lupus erythematosus, polymorphous light eruption, lymphocytic infiltration of Jessner, and cutaneous lymphoid hyperplasia: a comparative differential study

Cutaneous lupus erythematosus (LE), polymorphous light-eruption (PMLE), lymphocytic infiltration of Jessner (LIJ), and cutaneous lymphoid hyperplasia (CLH) are often difficult to differentiate from one another by light microscopic examination. We conducted an immunohistochemical analysis of the mononuclear cell infiltrates in 13 LE, 12 PMLE, 10 LIJ, and 13 CLH with various antibodies. Antibodies L26, UCHL1, and S100 achieved statistically significant differences among the four diseases, but because of the overlaps in the number of UCHL1(+) T cells and S100 protein (+) cells in individual cases, these two antibodies were not useful. Only CLH could be distinguished from LE, PMLE, and LIJ by a greater number of CD20(+) B cells. The latter three conditions could not be differentiated. Contrary to previous reports, plasmacytoid-monocytes were not found to be increased in LIJ for the differentiation of the latter from LE and PMLE. Our results support the conclusion that CLH is a reactive lymphoid hyperplastic process with proliferation of both B and T cells, whereas the T cell was the predominant cell type in the infiltrates of LE, PMLE, and LIJ, indicating that they were related to T cell disorders. The histiocyte was only a minor component cell. The plasmacytoid monocyte in general was not significantly present in all four conditions, but relatively more plasmacytoid monocytes were present in CLH.

A long lytic cycle in filamentous phage Cf1tv infecting Xanthomonas campestris pv. citri

In this study the lytic cycle of a filamentous phage is reported. Under normal laboratory cultivation conditions a virulent form could spontaneously and easily arise from a temperate phage. The virulent one could superinfect cells containing Cf1t lysogen. Therefore, we have named it Cf1tv. In a colony formation assay using cells from an infected culture, two types of colonies were observed, small and large. It could be proven that the formation of small colonies is the result of killing during Cf1tv infection. The number of small colony forming units (cfu) increased with infection time and reached a maximum at 16 h after infection, then dropped to the initial cell concentration at 28 h after infection; 28 h were required to kill all infected cells. Large colonies contained uninfected or phage-resistant cells, but no lysogenic cells. Bacterial death was further confirmed by a microculture assay. At 2 h after infection, normal-dividing cells (cfu giving large colonies) contained about 40% of Cf1tv-infected cells, then the percentage decreased with infection time. Slow-dividing cells (infected cfu giving small colonies) initially contained 55% of cells; this percentage increased slightly at 4 h after infection, then decreased at 8 h after infection. Non-dividing cells initially contained 5% of infected cells, then their numbers rapidly increased with time after infection. The cell division was seriously affected and finally stopped. During one-step growth, the latent period was 30 min and there was no burst; phages were released at 30 min after infection and the rate of release increased gradually with time after infection. Phage DNA integration into host chromosome could not be observed.

Anticentromere antibodies (ACA): clinical distribution and disease specificity

Sera from 3528 patients with autoimmune disease, and non-autoimmune disease, and 500 normal individuals were studied for the presence of anticentromere antibodies (ACA) by indirect immunofluorescence on HEP-2 cells. Sixty-seven specimens were identified showing discrete speckled staining: 55 (82.1%), 11 (16.4%), and one (1.5%), were from patients with autoimmune disease, non-autoimmune disease and normal control subjects, respectively. These ACA were present frequently in CREST syndrome (55%), Raynaud's disease (29.6%) and primary biliary cirrhosis (30%). Only 16.4% of the antibody positive patients carried a clinical diagnosis of CREST, which means that ACA are not specific for CREST syndrome. High antibody titre persisted irrespective of whether or not the patients had active disease. The ACA were present infrequently in Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, immune thrombocytopenic purpura, Graves' disease, immune haemolytic anaemia, and vitiligo. Sera from 107 patients with various other autoimmune diseases were negative for ACA.

Primary small-intestinal lymphomas in Taiwan: immunoproliferative small-intestinal disease and nonimmunoproliferative small-intestinal disease

PURPOSE

The clinicopathologic findings in 45 adult Chinese patients with primary small-intestinal lymphoma (PSIL) are described and compared with those in Western countries and in underdeveloped nations. The efficacy of combination chemotherapy is also assessed.

PATIENTS AND METHOD

Six patients had immunoproliferative small-intestinal disease (IPSID) indicated by the presence of alpha-heavy chain protein (alpha-CP) in body fluids or tumor tissues. Thirty-nine patients had non-IPSID, including one with postrenal transplant lymphoma. Thirty-three non-IPSID patients received a minimum of four cycles of combination chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP).

RESULTS

All IPSID patients presented with the clinical and laboratory features of severe intestinal malabsorption, and all had diffuse lymphoplasmacytic infiltration in the mucosa of the small bowel. Lymphomas were localized mainly in the jejunum and mesenteric nodes. The histologic subtypes were diffuse large cell in two, immunoblastic in three, and diffuse mixed in one. All patients responded poorly to chemotherapy, with a median survival duration of 10.5 months. The common presenting symptoms of the 39 non-IPSID patients included abdominal pain (90%), weight loss (31%), abdominal mass (26%), obstruction (26%), and perforation (23%). Diffuse large-cell and immunoblastic lymphomas constituted 82% of cases. Four patients had stage IE, 19 stage II 1E, and 16 stage 112E disease according to the Musshoff's criteria; 22 had bulky tumors and 19 had multiple tumors. The tumors were completely resected in 14 patients. Of 33 patients treated with combination chemotherapy, 73% achieved a complete remission. With a median follow-up duration of 90 months, there have been four relapses, with only one at the primary tumor site. The overall 5-year survival and disease-free survival rates for non-IPSID patients who were treated with chemotherapy were 59% and 54%, respectively.

CONCLUSION

Intensive chemotherapy produces long-term disease-free survival in locally advanced non-IPSID PSIL.

Pancreatic tuberculosis mimicking pancreatic head carcinoma: a case report and review of the literature

A 24-year-old man presented with vague abdominal fullness and a mild epigastric dull pain for about 3 months was found to have a pancreatic head tumor at a medical center 2 months ago. He came to our hospital for further treatment. Ultrasonography, endoscopic retrograde cholangiopancreatography (ERCP) and abdominal computed tomography (CT) all revealede a pancreatic head tumor. Laparotomy was performed because pancreatic head carcinoma was highly suspected. Indurated mass in the pancreatic head, enlarged lymph nodes and white tubercles on the intestine proved to be tuberculosis on histological examination of a frozen section. Acid fast bacilli were also found. The patient was given antituberculous therapy and is now doing well. To avoid unnecessary laparotomy, CT, echo-guided percutaneous aspiration cytology or biopsy and culture of the tissue for mycobacteria should be done in a patient with pancreatic mass, especially in a region where pulmonary and abdominal tuberculosis are common.

Sweet's syndrome: clinicopathologic study of eleven cases

BACKGROUND

The clinicopathologic manifestations of Sweet's syndrome associated with malignancy have been rarely studied in a large series.

METHODS

We describe the clinical features of Sweet's syndrome in 11 patients seen during the past 12 years. Histopathologic findings of these patients are discussed. The clinicopathologic manifestations of 249 cases of Sweet's syndrome reported in the literature were reviewed.

RESULTS

The clinicopathologic manifestations of Sweet's syndrome associated with hematologic disorders (HSS) were more severe and characterized by bullous pyoderma with more pronounced epidermal changes and ulceration, anemia, giant platelets and abnormal platelet counts. Approximately 40% of the Sweet's syndrome reported in the literature were associated with hematologic malignancy, and the other 7% of patients had solid tumors.

CONCLUSIONS

Sweet's syndrome can be classified into three types: (1) association with hematologic disorders (HSS); (2) association with solid tumors (SSS); and (3) idiopathic or associated with various other disorders (ISS).

Specific protein phosphorylation induced in Xanthomonas campestris pv. oryzae by bacteriophage Xp12

We have investigated the endogenous phosphorylation patterns of phosphorylated proteins of Xanthomonas campestris pv. oryzae induced by its bacteriophages. For bacteriophage Xp12-infected cells, at least three phosphoproteins with apparent molecular weights of 28, 28.5 and 45 kDa were detected by in vitro labeling with [gamma-32P]-ATP. These Xp12-specific phosphoproteins only occurred with Xp12 infection, and were not shown in uninfected or Xp10-infected cells. The protein kinase(s) responsible could use either ATP or GTP as the nucleotide substrate with nearly the same efficiency. Magnesium was proved to be an essential factor for the phosphorylation. EGTA treatment excluding the possibility that the presumed protein kinase was calcium-dependent. Under our reaction conditions, the optimal phosphorylation occurred at pH 7 to 8, for 30 to 40 min at 25 to 37 degrees C. The Xp12-specific protein phosphorylation hint the existence of a physiological regulation mechanism involved in the life cycle of bacteriophage Xp12. Furthermore, the presumed protein kinase was shown to be encoded by the genome of Xp12 rather than indirectly induced by Xp12 infection.

Cutaneous manifestations of non-01 Vibrio cholerae septicemia with gastroenteritis and meningitis

A 58-year-old man with diabetes had fever and chills 5 days after ingestion of raw seafood. Nausea, vomiting, watery diarrhea, bilateral calf pain, and neck stiffness subsequently developed. Generalized edema and ecchymotic patches with a vesiculobullous eruption appeared on the extremities. Four blood cultures were positive for Vibrio cholerae non-01. The patient was successfully treated with antibiotics. This is the first documented case of V. cholerae non-01 septicemia with cutaneous lesions and meningitis in Taiwan.

Ossifying dermatofibroma with osteoclast-like giant cells

Dermatofibroma or cutaneous fibrous histiocytoma is a common cutaneous tumor. Rare histologic variants have been described. We report another variant of dermatofibroma characterized by osteoclast-like giant cells with metaplastic bone formation. Clinically the lesion was a small, brown, hard papule of several months' duration on the left anterior leg of a 58-year-old woman.

Carcinoid tumor of the thymus with divergent sarcomatoid differentiation: report of a case with histogenetic consideration

An anterior mediastinal tumor resected from a 54-year-old man without paraneoplastic symptoms was found to be an unusual biphasic thymic tumor composed of carcinoid tumor in sarcomatous stroma characterized by fibrosarcoma-like spindle cells with areas of chondroid and osseous differentiation. Immunohistochemical and ultrastructural studies verified that the tumor described was a carcinoid tumor with divergent sarcomatoid differentiation rather than a mixed carcinoid tumor and sarcoma. The chondroid and osseous differentiations observed were unique features. This tumor is rare and provides an opportunity for understanding tumors with divergent components. The sarcomatoid transformation of thymic carcinoid tumor might denote highly malignant clinical behavior as illustrated by this case.

University of Wisconsin solution extends lung preservation after prostaglandin E1 infusion

University of Wisconsin (UW) solution has been demonstrated to enhance and extend the preservation of the hepatic, pancreatic, renal, and cardiac allografts. Prostaglandin E1 (PGE1), which has been used to produce pulmonary vasodilatation, has improved preservation in lung transplantation. Experiments were designed to evaluate their potential role in 24-h preservation of the allografts in lung transplantation. Thirty-six dogs underwent left lung transplantation. The donor lungs (n = 6 in each group) were flushed with UW solution (group 1 and 2) or modified Euro-Collins (EC) solution (group 3) after PGE1 infusion (500 micrograms). In group 1, donor lungs were transplanted immediately. Lung allografts of group 2 and 3 were cold stored (4 degrees C) in the same preservation solution for 24 h in the inflated state and then transplanted. The right pulmonary artery and right main bronchus were ligated 1 h after completion of the transplantation, forcing the recipient dogs to survive with the transplanted left lung. The recipients were ventilated with an inspired oxygen fraction of 0.4 and end-expiratory pressure 10 cm H2O. Two dogs died prematurely in group 3, whereas all dogs in group 1 and 2 survived the experimental period. The arterial oxygen tension and saturation and dynamic lung compliance were significantly higher in dogs of group 1 and 2. Transplanted lungs of group 1 and 2 had significantly lower pulmonary vascular resistance, alveolar-arterial oxygen difference, and wet/dry lung weight ratio. Histologically, pulmonary edema, congestion, sloughing of bronchial mucosa, and peribronchial and peripulmonary arterial hemorrhage were shown in lungs of group 3, but not in those of group 1 and 2. Airway mucosa and pulmonary vascular structure were well preserved in lungs of group 1 and 2. There was no significant difference between group 1 and 2 in lung functions, hemodynamics, or morphologic features. We concluded that PGE1 and UW solution could effectively extend lung preservation up to 24 h in this in vivo canine lung allotransplantation model.

DNA flow cytometric study of thymic epithelial tumors with evaluation of its usefulness in the pathologic classification

A DNA flow cytometric study was performed on 64 thymic epithelial tumors using the modified Hedley method with formalin-fixed, paraffin-embedded tissues to evaluate whether ploidy analysis can be a useful aid in differentiating invasive thymoma (IT) from non-invasive thymoma (NT) and in understanding the ploidy pattern of various histologic types of thymic carcinomas (TCs). The IT group was further subdivided into macroinvasive thymoma (macro-IT) and microinvasive thymoma (micro-IT). Six cases were excluded due to a coefficient of variation greater than 6. Aneuploidy with a DNA index greater than 1.05 was found in every group: two of 16 NTs, two of nine micro-ITs, 11 of 13 macro-ITs, and 12 of 20 TCs were aneuploid. However, the proportions of aneuploidy of macro-IT and TC were statistically significantly higher than those of NT and micro-IT (P < .001). Similarly, the DNA indexes of macro-IT and TC were significantly higher than those of NT and micro-IT (P < .004). Therefore, micro-ITs were cytometrically similar to NTs and could be grouped with the NTs. Although ploidy analysis cannot predict whether an individual thymoma is invasive, aneuploidy and a high DNA index would favor a macro-IT, which also has a significantly higher S-phase fraction. Thymic carcinoma and IT cannot be differentiated by DNA flow cytometry. No definite ploidy pattern was observed for various histologic types of TC, but transition from diploid to aneuploid was demonstrated in thymomas undergoing malignant transformation into TC.

Thymoma: a study of the pathologic classification of 71 cases with evaluation of the Muller-Hermelink system

A pathologic study of 71 consecutive cases of thymoma was conducted to determine the value of histologic classification for predicting the invasive potential of thymomas. The traditional and newly proposed Muller-Hermelink classification systems were studied for correlation with thymomas of the three clinicopathologic stages identified as noninvasive thymoma, microinvasive thymoma, and macroinvasive thymoma. None of the histologic types classified by the traditional system were correlated specifically with invasive growth. In contrast, the cortical-type thymoma of the Muller-Hermelink system correlated strongly with both microinvasive thymoma and macroinvasive thymoma (P < .001 for both). Although not all cortical thymomas manifested invasive growth and not all invasive thymomas were of the cortical type, the statistical data suggested that cortical thymomas should be regarded as potentially malignant tumors with the propensity for invasive growth. Spindle-cell thymoma of the traditional system or medullary thymoma of the Muller-Hermelink system, on the other hand, was not associated with invasiveness and behaved as a benign tumor. All other thymomas that were not purely spindle cell or medullary cell in nature had a potential for invasion and aggressive behavior, and this potential seemed to be inversely proportional to the percentage of fusiform cells in such neoplasms. Nevertheless, the results of this study support the usefulness of the Muller-Hermelink classification system in predicting the aggressive potential of thymomas. A group of microinvasive thymomas was identified as a separate group for analysis in this study. Although no recurrences were observed during the follow-up period, microinvasive thymomas deserve further study as a separate group because they correlated strongly with cortical thymoma. The association of thymoma with myasthenia gravis was rather high (63.4%) in this study. Both the mixed-type thymoma of the traditional classification system and the cortical-type thymoma of the Muller-Hermelink system showed statistically significant correlation with myasthenia gravis (P = .002 and .001, respectively).

alpha-Amylase as a marker for evaluating the stability of recombinant yeast in long-term cultivation

We describe here a simple method for analyzing the stability of recombinant yeast. The mouse salivary alpha-amylase gene was used in this system as a marker since the stability of recombinant yeast can be detected easily by a halo zone-for-ming assay on starch-supplemented plates. We used this method to evaluate the stability of recombinant yeast harbouring a 2 mu directed episomal plasmid and of yeast harbouring the r-DNA directed integrative vector. Our results demonstrated clearly that the alpha-amylase gene was a convenient and reliable marker for evaluating the stability of recombinant yeasts in long-term cultivation.

A simple and rapid method for the preparation of gram-negative bacterial genomic DNA

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Study of Epstein-Barr virus early RNA 1 (EBER1) expression by in situ hybridization in thymic epithelial tumors of Chinese patients in Taiwan

Forty-one thymic epithelial tumors from Chinese patients in Taiwan, including 14 noninvasive thymomas, seven invasive thymomas, and 20 thymic carcinomas, were investigated for the presence of Epstein-Barr virus transcripts by in situ hybridization using digoxigenin-labeled riboprobes for EBER1 expressions. None of the 14 noninvasive thymomas or seven invasive thymomas had detectable EBER1. Only one of 20 thymic carcinomas was positive for EBER1. This positive tumor was a lymphoepithelioma-like carcinoma found in a 19-year-old patient. Four different cases of lymphoepithelioma-like carcinoma were negative. Of note, the present case and all previously reported cases of Epstein-Barr virus-associated thymic carcinomas were lymphoepithelioma-like carcinomas. These results are consistent with those of several Western studies and do not support the view that there are geographic or racial differences affecting the role of Epstein-Barr virus in the pathogenesis of thymic epithelial tumors.

Acinar cell carcinoma of the pancreas. Report of two cases with complex histomorphologic features causing diagnostic problems

Two pancreatic acinar cell carcinomas with distinctive morphologic features are described. Both tumors showed a variable combination of different histomorphologic patterns formed by tumor cells in different degrees of acinar differentiation. They caused diagnostic problems involving differential diagnosis from normal pancreas and from mixed acinar-endocrine tumor. The presence of mitosis, nuclear atypia, and tumor necrosis are helpful for recognizing its neoplastic nature, and the ultrastructural finding of zymogen-like but not neurosecretory granules prevented the misdiagnosis of a mixed acinar-endocrine tumor. Immunohistochemical studies revealed variable immunostaining patterns corresponding to different types of tumor cell present. Both tumors were found to be aneuploid by flow cytometric DNA study. Our study confirmed previous observations that pancreatic acinar cell carcinomas are highly malignant tumors in spite of the fact that they can differentiate into highly differentiated acinar cells.

Intrathoracic extramedullary hematopoietic tumor in hemoglobin H disease

We report a Chinese patient with hemoglobin H (Hb H) disease who developed intrathoracic extramedullary hematopoiesis (EMH) 17 years following splenectomy for a blunt abdominal injury. The patient initially presented with extreme hyperbilirubinemia and multiple intrathoracic tumors. Hb H disease was diagnosed after investigation, and the marked jaundice, which declined gradually after supportive treatment, was attributed to his chronic hemolysis superimposed on an acute hepatitis C virus infection. A biopsy of the intrathoracic tumors revealed an EMH. Intrathoracic EMH, which is usually encountered in patients with beta-thalassemia and hereditary spherocytosis, has never been reported in Hb H disease. In areas where thalassemia is prevalent, EMH should be considered in the differential diagnosis of patients who have chronic anemia with asymptomatic intrathoracic tumor to avoid unnecessary surgical interventions.

New observations in a child with angiofollicular lymph node hyperplasia (Castleman's disease) originated from the mesenteric root

Localized plasma cell type Castleman's disease (CD) is an unusual pathologic entity. It is frequently associated with clinical and laboratory characteristics and rarely occurs in children. Total surgical excision results in cure in all aspects. To make early diagnosis of mesenteric CD is not easy, especially for children. An 11-year-old Taiwanese boy was recently evaluated for anemia and delayed growth. His clinical findings included a syndrome of severe hypochromic microcytic anemia, neutropenia, thrombocytosis, hypoferremia, hypergammaglobulinemia, and growth failure. Radiological examinations (abdominal ultrasound, small intestinal series, and computerized tomography) identified hepatosplenomegaly, nephromegaly, and huge masses in the middle abdomen with precaval, celiac, and paraaortic lymph nodal enlargement. However, detailed physical examination failed to detect a mass. At laparotomy a double-fist-sized confluent mass was found arising from the mesenteric root. Most masses were discrete and were excised individually. The pathologic diagnosis was plasma-cell type angiofollicular lymph node hyperplasia (Castleman's disease). Seven weeks after surgery, he had an episode of acute hepatitis B. Postoperatively, he exhibited a dramatic growth spurt; the hemoglobin, red blood cell indices, serum iron, and immunoglobulins returned to normal in 2 months. Neutropenia, which has not been previously related to mesenteric CD, was an unexpected finding in our case; however, it resolved spontaneously 3 months after the surgery, suggesting its causal relationship with the tumor.

Prognosis of thymic carcinoma: analysis of 16 cases

Primary thymic carcinoma is a rare malignant neoplasm which arises from the thymic epithelium. Between May 1982 and September 1990, 16 patients with thymic carcinomas, diagnosed at Chang Gung Memorial Hospital, were reviewed. Their ages ranged from 19 to 75 years, with a median of 40 years. Males predominated (male to female ratio was 11:5). The most common presenting symptoms were chest pain, cough, body weight loss and dyspnea. No paraneoplastic syndromes were seen. Chest roentgenograms of 15 patients revealed a mediastinal mass, but a definitive diagnosis could not be made until surgery. Adjacent mediastinal tissues were invaded, or adhered to, by all the tumors. Six distinct histologic types were found, squamous cell carcinoma being the most common (seven cases). The primary treatment of surgical resection was attempted in 14 patients, but only in five cases could the tumors be completely resected; two had a biopsy only. Radiotherapy, with or without chemotherapy, given postoperatively, achieved additional local control in seven of the nine partially resected patients (77%). Distant metastasis occurred in nine of 16 patients (56%). Lymph nodes, bone and lung were the most common metastatic sites. Chemotherapy with cisplatin and/or adriamycin-based regimens was given to patients who had distant metastasis, but the responses were unsatisfactory. The overall survival at one, three and five years was 88%, 51% and 31%, respectively. The median survival was 30 months. The median survival of patients with pure squamous cell carcinoma (> 49 months) was superior to that of patients with other histologic types (18 months; p < 0.01).

Primary osteosarcoma of the skin

Primary cutaneous osteosarcoma is extremely rare. An extraskeletal osteosarcoma of the skin occurring in the popliteal region of a 51-year-old woman is described. There were no associated predisposing conditions.

Role of anisotropy in determining the selective action of antiarrhythmics in atrial flutter in the dog

OBJECTIVE

The aim was to clarify the electrophysiological and anatomical features of the preferential site of action of antiarrhythmic drugs in the re-entrant circuit of canine atrial flutter.

METHODS

Electrophysiological and anatomical findings were correlated in 17 anaesthetised adult mongrel dogs with atrial flutter associated with an intercaval anatomical obstacle, before and after intravenous administration of disopyramide (2 mg.kg-1) and flecainide (2 mg.kg-1).

RESULTS

Before drug injection, a rate dependent prolongation of conduction time occurred in the low right atrium where the conduction was slow during atrial flutter. Disopyramide (n = 8 dogs) and flecainide (n = 9 dogs) terminated atrial flutter, with conduction block occurring in this slow conduction area in the low right atrium. Although the degree of drug induced prolongation of refractoriness in this particular area was similar to those in other areas of the right atrium, conduction was depressed to a greater extent in this region. Anatomical study revealed that a thick pectinate muscle that branched from the crista or crista terminalis itself ran perpendicular to the wavefront of the pacing impulse and atrial flutter in this slow conduction area.

CONCLUSIONS

These data indicated that slow conduction might be attributed, at least in part, to anisotropic conduction over the thick muscle bundle in the low right atrium, and that antiarrhythmic drugs preferentially produced conduction block in this area. Anisotropic conduction in the low right arium is an anatomical substrate for slow conduction in the re-entrant circuit and for the site preference of antiarrhythmic drugs in the present canine model.

Kinetic study of alterations in the host RNA polymerase and protein synthesis during phage Xp 10 infection

We monitored the compositional change of host RNA polymerase in Xp 10 infected cells by one-step immunoprecipitation with core enzyme-specific antiserum. Results showed a rapid loss of sigma subunit from the RNA polymerase complex by 3 min after infection. In addition, some putative binding proteins were reduced to various extents. In contrast, increasing levels of several other polypeptides were detected. The de novo host protein synthesis was inhibited within 1 min after Xp 10 infection. On the other hand, a sequential expression of phage specific proteins was found and can be categorized as early, middle, and late stage. The alteration of host RNA polymerase and the shutdown of early class proteins took place in parallel.

Functional expression of rat M5 muscarinic acetylcholine receptor in yeast

We have produced the rat M5 muscarinic acetylcholine receptor, an integral membrane protein, in the yeast Saccharomyces cerevisiae. This was achieved by placing an M5 gene in the yeast vector under the control of the yeast alpha-factor promoter and leader sequence. Northern blotting revealed the presence of M5 transcripts in yeast transformed with the M5 plasmid constructs. Crude extract prepared from the transformant yeasts showed saturable binding of the muscarinic antagonist [3H]-N-methyl scopolamine ([3H]NMS) with a kd of 22.77 nM and Bmax of 134.76 fmole per mg protein. Results deduced from saturation binding assay of intact cell demonstrated clearly that the M5 receptor was translocated across the membrane of the endoplasmic reticulum using the secretion signal on alpha-leader sequence and its binding site was still functional. Yeast expressing M5 receptor did not exhibit cell-cycle arrest in the presence of carbachol, a acetylcholine agonist, indicating that the recombinant M5 receptor could not couple directly to the endogenous yeast pheromone signaling G-protein.

HTLV-I-positive and HTLV-I-negative peripheral T-cell lymphomas in Taiwan Chinese

The clinico-pathologic features of 107 adult Chinese patients with peripheral T-cell lymphoma (excluding primary cutaneous lymphoma) are described and a comparison between HTLVI+ and HTLV-I- patients is made. There were 27 HTLV-I+ and 80 HTLV-I- patients. The virus-positive and -negative groups both had a male predominance and an identical median age of 48. Most patients in both groups presented with stage-IV disease, B symptoms, lymphadenopathy and hepatosplenomegaly. The HTLV-I+ group had a significantly higher incidence of skin and pulmonary lesions, bone marrow and peripheral blood involvement, hypercalcemia, and elevated LDH level compared to the HTLV-I- group. Sinonasal lesions (10), mediastinal mass (5), and GI tract involvement (6) were only seen in the HTLV-I- group. Leukocytosis with the presence of circulating pleomorphic lymphoid cells was characteristic of HTLV-I+ cases, while cytopenia was more frequently present in HTLV-I- cases. All of the 24 HTLV-I+ patients tested were CD4+CD8-; of the 67 HTLV-I- patients tested, 46 were CD4+CD8-, 9 were CD4-CD8 , 5 were CD4-CD8- and 7 were CD4+CD8+. Phenotypic studies revealed significant differences in the expression of CD7 and CD25 between virus-positive and -negative groups. Both groups responded poorly to therapy. The median survival of HTLVI+ and HTLV-I- patients was 4 months and 13.5 months, respectively. Apart from the presence of more than 3 extranodal lesions, none of the other clinical features or histologic subtypes had prognostic significance in the entire group or either of the subgroups. This series of peripheral T-cell lymphomas in Taiwan indicate that HTLV-I+ and HTLV-I- patients had many features in common, but presented several distinct differences.

One-step transformation of yeast in stationary phase

A fast yeast-transformation technique has been developed by adding thio compounds to alkali-ion based protocols and incubating at 45 degrees C. This procedure is especially recommended for cells from stationary phase at a density up to 2.5 x 10(8) cells/ml. It involves only one step for the preparation and transformation of competent cells within 30 min. The yield was more than 10(4) transformants/microgram plasmid DNA. This protocol is easy to scale up for many DNA samples and is also applicable for yeast cells from different types of storages.

Atrophie blanche. A clinicopathological study of 27 patients

Twenty seven patients (8 males and 19 females) with atrophie blanche were observed in the past 7-years. The mean age at onset was 32 years (ranging from 23 years to 57 years) and 19 years (ranging from 11 years to 36 years) for male and female patient, respectively. The mean disease duration was 2.5 years (ranging from 2 months to 16 years) prior to their consultation. Sixty-three percent of them had summer exacerbation. Four patients had essential cryoglobulinemia, one of whom also developed bilateral iliofemoral artery stenosis one year later. Twelve patients also manifested concurrent purpura pigmentosa chronica (PPC)-like lesions. The observation of the natural course and clinical morphology, being divided into white atrophy-predominant and ulcer-predominant type, led to the impression that atrophie blanche and livedo vasculitis are synonyms with the same disease spectrum. Furthermore, white atrophy is not ulcer scars but lesions de novo suggesting dermal vasculopathy. An attempt was made to explain the uniqueness of clinical morphology. First line treatment included local wound care, bed rest and low-dose aspirin plus dipyridamole. Thirteen patients responded to these treatment either at the first attack or the recurrent episodes. Heparin (5000 units subcutaneous injection once daily) was effective for control of intractable painful ulceration in active stage in 70% of the remaining patients.

Expression of perforin by natural killer cells within first trimester endometrium in humans

The lymphocyte pore-forming protein (PFP)--perforin, also named cytolysin--is a potent mediator of cytotoxicity found in the granules of cytotoxic T lymphocytes and natural killer (NK) cells. Granulated metrial gland (GMG) cells found in the pregnant mouse uterus express perforin and are thought to be highly activated cytolytic lymphocytes related to NK cells. Their role in pregnancy is unknown. Human endometrial granulocytes (EGs) are phenotypically similar to murine GMG cells and, like them, express NK cell markers. However, up to now it was not known whether EGs also express perforin. By means of immunohistochemical analysis, using antisera specific for perforin and monoclonal antibodies to CD56 (NKH-1), CD2 (T11), CD3 (Leu-4), CD4 (Leu-3a), and CD8 (OKT-8), we demonstrated that perforin is present in EGs in the decidualized endometrial stroma and decidual tissue of first-trimester gestational endometrium. In fact, double immunohistochemical labeling demonstrated the co-expression of perforin and NKH-1. This population also expressed some T-cell surface antigens (Leu-4 and T11), but not Leu-3a or OKT-8. Chorionic villi, in contrast, lack perforin+ cells. The presence of a potent cytolytic mediator in NK-like cells in both murine and human pregnant uterus raises the issue of the function of such cells in pregnancy.