Spontaneous apoptosis in the intra-ductal component's stroma of breast invasive carcinoma

Spontaneous apoptosis by in situ detection of DNA fragmentation (DNAf) was investigated in breast invasive ductal carcinoma (IDC) frozen samples removed from 61 untreated patients. The incidence of DNAf was low in carcinoma cells and was mainly detected in the stroma. In the stroma at a distance from carcinoma cells, DNAf was inversely related to estradiol plasma level variations (p=0.01), indicating that it probably remained under physiological hormonal regulation. In the stroma adjacent to carcinoma cells, DNAf was correlated to tumor progression parameters such as the presence of a comedo intra ductal carcinoma (DCIS) component (p=0.001) and axillary lymph node metastasis (p=0.002), suggesting that this stromal compartment more probably represented a tumoral component closely associated to epithelial tumor cells. Therefore, the detection of DNAf in the adjacent stroma of breast carcinoma could help to predict progression in non invasive tumors and also in invasive tumors in those patients without lymph node invasion.

Physiological, biochemical and molecular analysis of sugar-starvation responses in tomato roots

Two-month-old tomato plants were submitted to day/night cycles and to prolonged darkness in order to investigate the physiological and biochemical response to sugar starvation in sink organs. Roots appeared particularly sensitive to the cessation of photosynthesis, as revealed by the reduction of the growth rate and the decline of the carbohydrate and protein content. Therefore, excised tomato roots were used as a model to deepen the characterization of sugar starvation symptoms. In excised roots, the endogenous sugars were rapidly exhausted and significant degradation of protein was observed. Glutamine and asparagine accounted for most of the nitrogen released by protein breakdown. Respiration declined and proliferation- and growth-associated genes were repressed soon after the beginning of the sugar depletion. Among the genes studied, only the gene encoding asparagine synthetase was strongly induced. All the starvation symptoms were reversible when the roots were resupplied with sugar. When the culture conditions deteriorated, the metabolic and molecular changes led to the triggering of apoptosis of the root cells.

Time-course of tomato whole-plant respiration and fruit and stem growth during prolonged darkness in relation to carbohydrate reserves

To evaluate the relevance of a simple carbon balance model (Seginer et al., 1994, Scientia Horticulturae 60: 55-80) in source-limiting conditions, the dynamics of growth, respiration and carbohydrate reserves of tomato plants were observed in prolonged darkness. Four days prior to the experiments, plants were exposed to high or low light levels and CO(2) concentrations. The concentration of carbohydrates in vegetative organs was 30-50 % lower in plants that were exposed to low carbon assimilation conditions compared with those exposed to high carbon assimilation conditions. During prolonged darkness, plants with low carbohydrate reserves exhibited a lower whole-plant respiration rate, which decreased rapidly to almost zero after 24 h, and carbohydrate pools were almost exhausted in leaves, roots and flowers. In plants with high carbohydrate reserves, the whole-plant respiration rate was maintained for a longer period and carbohydrates remained available for at least 48 h in leaves and flowers. In contrast, fruits maintained fairly stable and identical concentrations of carbohydrates and the reduction in their rate of expansion was moderate irrespective of the pre-treatment carbon assimilation conditions. The time-course of asparagine and glutamine concentrations showed the occurrence of carbon stress in leaves and flowers. Estimation of source and sink activities indicated that even after low carbon assimilation, vegetative organs contained enough carbohydrates to support fruit growth provided their own growth stopped. The time of exhaustion of these carbohydrates corresponded grossly to the maintenance stage simulated by the model proposed by Seginer et al. (1994), thus validating the use of such a model for optimizing plant growth.

Intrasinusoidal bone marrow infiltration: a common growth pattern for different lymphoma subtypes

We report a retrospective immunohistochemical study on bone marrow biopsies of 43 patients with different types of lymphomas showing unusual intrasinusoidal infiltration. Most of these patients presented with splenomegaly (74.4%) and peripheral lymphocytosis (83%). In 20/43 patients, lymphoid infiltrates were not detectable on haematoxylin-eosin sections. After immunohistochemistry on bone marrow biopsies and blood and bone marrow smear examinations, the following diagnoses were made: splenic marginal zone lymphoma with villous lymphocytes (SLVL) in 24 patients, large granular lymphocyte (LGL) leukaemia in 14 patients, hepatosplenic T-cell lymphoma in two patients, anaplastic large cell lymphoma in two patients and intravascular large B-cell lymphoma in one patient. In the presence of intrasinusoidal infiltrates of small lymphocytes, a B-cell phenotype (CD20+, CD76/DBA44+/-) was associated with splenic marginal zone lymphoma whereas intrasinusoidal CD3/CD45RA-positive T-cell infiltrates were strongly suggestive of LGL leukaemia. Intrasinusoidal bone marrow infiltration appears to be a common feature of distinct lymphoma subtypes. Immunohistochemical analysis is essential to detect intrasinusoidal medullary infiltrates (which may be minimal) and should be systematically performed in patients with splenomegaly and peripheral lymphocytosis.

Anaplastic lymphoma kinase (ALK) protein expressing lymphoma after liver transplantation: case report and literature review

Most post transplantation lymphoproliferative disorders (PTLDs) are Epstein-Barr virus (EBV) associated B cell proliferations. We report a case of aggressive anaplastic large cell lymphoma expressing the anaplastic lymphoma kinase (ALK) protein in a 58 year old man who had previously undergone liver transplantation. A definite diagnosis was not possible on histopathological examination. Immunostaining clearly showed a predominant population of small irregular lymphocytes, admixed with large cells strongly positive for CD30, epithelial membrane antigen, and the ALK protein. Neoplastic cells were of the T/cytotoxic phenotype. In situ hybridisation with EBV encoded early RNA probes showed only a few scattered positive non-neoplastic small lymphocytes. Polymerase chain reaction analysis of immunoglobulin and T cell receptor rearrangements was negative. The NPM-ALK fusion transcript associated with the t(2;5) translocation was detected by reverse transcription polymerase chain reaction. A review of the literature revealed 76 cases of T cell PTLD, showing a broad spectrum of morphological features and clinical behaviour. Most of these cases were EBV negative (61 of 76) and occurred after renal transplantation (48 of 76). To our knowledge, this is the first case of ALK positive lymphoma occurring in the setting of organ transplantation. This observation stresses the need for accurate immunostaining for diagnosing this rare, apparently aggressive, lymphoma in immunosuppressed patients.

A fruit-specific phospho enolpyruvate carboxylase is related to rapid growth of tomato fruit

Malic and citric acids accumulate in cherry tomato (Lycopersicon esculentum Mill.) fruit during the period of rapid growth, from the end of cell division to the onset of ripening. The involvement of phospho enolpyruvate carboxylase (PEPCase, EC 4.1.1.31) in organic acid accumulation and tomato fruit development was investigated. Two PEPCases, named LYCes;Ppc1 and LYCes;Ppc2 and mapped to chromosomes 12 and 7, respectively, were shown to be differentially expressed during tomato fruit development. LYCes;Ppc1 mRNA was present in all fruit tissues and in all other plant organs examined. In contrast, LYCes;Ppc2 was strongly and specifically expressed in fruit from the end of cell division to ripening. No LYCes;Ppc2 expression was detected by northern blot in other plant tissues. In fruit, the increase in LYCes;Ppc2 mRNA was closely followed by an increase in fruit PEPCase protein and activity, and was coincident with the increased accumulation of malate and citrate during the initial period of rapid growth rate, from 8 to 20 days post anthesis. Localization of LYCes;Ppc2 mRNA in young tomato fruit by in situ hybridization revealed that LYCes;Ppc2 is preferentially expressed in large cells of the pericarp and in enlarging cells of the gel surrounding the seeds. Examination of the kinetic and regulatory properties of the PEPCases of growing and ripening fruit further showed that PEPCase in growing fruit is less sensitive to low pH and malate inhibition, indicating a high phosphorylation state and/or the presence of a PEPCase isoform with these characteristics. Taken together, these results indicate that in developing tomato fruit PEPCase is probably important in permitting the synthesis of organic acids to provide the turgor pressure necessary for cell expansion.

[Germ cell tumors of testis, current concepts]

Histological pleomorphism of testicular germ cell tumors complicates diagnosis. These tumors share highly specific differentiation properties ranging from intra-tubular neoplasia to classical infiltrating lesions. This general review presents the histopathological features and diagnostic criteria of typical forms and atypical variants. In current practice, distinction between seminoma and non-seminomatous germ cell tumors is fundamental for treatment. Histological typing of non-seminomatous tumors may be problematical, especially in "mixed" forms. Vitelline tumor variants and atypical embryonic carcinoma are described. Unlike scattered isolated syncytiotrophoblastic cells, true chorio-carcinoma is rare and must be carefully identified. Such cells are frequently associated with seminoma, embryonic carcinoma and vitelline tumors. Intra-tubular germ-cell neoplasia and gonadoblastoma, are pre-invasive lesions associated with cryptorchidism and gonadal dysgenesis. Teratomatous elements usually occur in mixed germ cell tumors. Rare pure teratoma are benign in children. On the contrary, post-pubertal forms have an unpredictable evolution.

Form I Rubiscos from non-green algae are expressed abundantly but not assembled in tobacco chloroplasts

Non-green algae have Rubiscos that are phylogenetically distinct from their counterparts in green algae and higher plants. Some non-green-algal Rubiscos are more specific for CO2, relative to O2, than higher-plant Rubiscos, sometimes coupled with lower Michaelis constants for CO2. If these Rubiscos could be substituted for the higher-plant enzyme, and if they functioned successfully in the higher-plant chloroplast and were regulated appropriately, they would improve the CO2 use and quantum efficiency of higher-plant photosynthesis. To assess the feasibility of expressing non-green algal Rubiscos in higher-plant chloroplasts, we inserted the rbcLS operons from the rhodophyte Galdieria sulphuraria and the diatom Phaeodactylum tricornutum into the inverted repeats of the plastid genome of tobacco, leaving the tobacco rbcL gene unaltered. Homoplasmic transformants were selected. The transgenes directed the synthesis of abundant amounts of transcripts and both subunits of the foreign Rubiscos. In some circumstances, leaves of the transformants with the P. tricornutum Rubisco contained as much foreign Rubisco protein as endogenous tobacco Rubisco (>30% of the soluble leaf protein). However, the subunits of the foreign Rubiscos were not properly folded and/or assembled. All the foreign large subunits and most of the foreign small subunits were recovered in the insoluble fractions of leaf extracts. Edman sequencing yielded the expected N-terminal sequences for the foreign small subunits but the N-termini of the foreign large subunits were blocked. Accumulation of large amounts of denatured foreign Rubisco in the leaves, particularly of the P. tricornutum transformants, caused a reduction in the amount of tobacco Rubisco present, with concomitant reductions in leaf CO2 assimilation and plant growth.

Unlikely role of Epstein-Barr virus in the pathogenesis of primary cutaneous CD30+ anaplastic large cell lymphoma

BACKGROUND

Primary cutaneous CD30+ anaplastic large cell lymphoma (ALCL) is a rare subset of cutaneous lymphoma, with a much better prognosis than its nodal counterpart. The pathogenesis of both nodal and primary cutaneous CD30+ ALCL is largely unknown but experimental data support the hypothesis that the Epstein-Barr virus could play a role in the nodal subset.

OBJECTIVE

To evaluate the involvement of Epstein-Barr Virus (EBV) in primary cutaneous CD30+ ALCL by searching for both nucleic acids and EBV proteins in cutaneous lesions.

SETTING

Two University Hospitals in Southern France (secondary referral hospitals).

PATIENTS

Eight consecutive patients with typical primary cutaneous CD30+ anaplastic large cell lymphoma were studied.

METHODS

Search for the presence of DNA, RNA and EBV proteins in cutaneous lesions by PCR, in situ hybridization and immunohistochemistry.

RESULTS

EBV DNA and RNA was identified in only one lesion of primary cutaneous CD30+ ALCL and in none of the normal adjacent skin samples. In situ hybridization and immunohistological studies were consistently negative in all samples.

CONCLUSION

These results do not support an early role of EBV in the oncogenetic pathogenesis of primary cutaneous CD30+ ALCL.

[Actinomycosis after renal transplantation: apropos of 1 case and review of the literature]

Actinomycosis is a suppurative infection usually due to a facultative anaerobic bacteria, actinomyces israelii. This rare infection has been reported in immunocompetent individuals, with buccal or pharyngeal mucosal erosions. Paradoxically, few cases have been observed after solid organ transplantation: 2 cases after lung, 1 case after heart-lung transplantation and 1 case after renal transplantation. We report on a renal transplant recipient who developed a tongue and oropharynx suppurative abscess, looking like an epithelioma. Histological examination showed granulomatous inflammation with an angiofibroblastic reaction; few colonies of actinomyces were also observed by the pathologist. This lesion disappeared easily and totally after tetracycline treatment.

Decreased expression of estrogen receptor beta protein in proliferative preinvasive mammary tumors

To understand the significance of estrogen receptor beta (ERbeta) in mammary carcinogenesis, we evaluated the expression of ERbeta in preinvasive mammary tumors. The percentage of ERbeta-positive epithelial or tumoral cells was assayed by quantitative immunohistochemistry using an image analyzer in 130 lesions of varying histological risk from 118 patients [71 with benign breast disease (BBD) and 59 with carcinoma in situ (CIS)] and compared with 118 adjacent histologically normal glands. Five groups of lesions with an increasing risk of invasive cancer, from BBD without hyperplasia to high-grade CIS, were studied. Results were compared with ERalpha and Ki67 immunostaining. The percentage of ERbeta-positive cells was high (median, 85%) in "normal" mammary glands and in nonproliferative BBD and decreased significantly (P < 0.0001) in proliferative BBD without atypia and in CIS, contrasting with an inverse progression for the ERalpha level. In normal mammary glands, the ERbeta level did not vary according to the nature of the lesion at the periphery and was significantly higher (P < 0.007) than in adjacent preinvasive lesions, except in nonproliferative BBD. The ERbeta level decreased in proliferative BBD, anticipating the ERalpha increase, which was significant in BBD with atypia. In high-grade ductal carcinoma in situ, both ER levels were low. The ratio between ERbeta and ERalpha was high in normal glands, and decreased significantly in proliferative lesions. ERbeta staining was inversely correlated with Ki67 (r = -0.333; P < 0.001), more particularly in high-grade ductal carcinoma in situ (r = -0.57; P < 0.02). The marked and early decreased level of ERbeta protein associated with other criteria of cell proliferation suggests a protective effect of ERbeta against the mitogenic activity of estrogens in mammary premalignant lesions. Knowledge of the ERbeta and ERalpha content in each preinvasive lesion should help to rationalize antiestrogen preventive therapy adapted to each individual patient.

[Association of Kaposi sarcoma--multiple myeloma. A new case]

INTRODUCTION

Kaposi's disease is an angiogenic multifocal cancer process that has several forms, namely Mediterranean, African, HIV-associated, and secondary to a preexisting immunodepressive state (hematological disorder, corticosteroid therapy, immunodepressive treatment). Whatever its form, Kaposi's sarcoma is probably associated with a chronic viral human herpes type 8 infection (HHV8).

EXEGESIS

This virus has been implicated in the pathogenesis of multiple myeloma (17 cases recorded to date). In the present study, a further case of Kaposi's sarcoma associated with multiple myeloma has been reported. However, Epstein-Barr virus, cytomegalovirus, hepatitis B and C, HIV and HHV8 serologies were negative. Radiotherapy on the lower limbs was initiated.

CONCLUSION

It is concluded that HHV8 does not appear to play a pathogenic role in cases of multiple myeloma, given the rarity of the association between Kaposi's sarcoma/multiple myeloma/HHV8.

Dissociated overexpression of cathepsin D and estrogen receptor alpha in preinvasive mammary tumors

The role of estrogen as a promoter agent of sporadic breast cancer has been considered by assaying, in benign breast disease (BBD) and in situ carcinomas (CIS), 2 markers, the estrogen receptor alpha (ERalpha) and cathepsin D (cath-D) involved in estrogen action on mammary tissue. ERalpha and cath-D were assayed by quantitative immunohistochemistry using an image analyzer in 170 lesions of varying histological risk (94 BBD and 76 CIS), and in "normal" glands close to these lesions. The ERalpha level increased significantly in proliferative BBD with atypia (P < .001), in non-high-grade CIS (P < .001), and in adjacent "normal" glands. ERalpha level was decreased in high-grade ductal CIS (DCIS) and also in adjacent "normal" glands. Cath-D level increased in ductal proliferative BBD (P < or = .01) and in high-grade DCIS (P < or = .003), but not in the other lesions. After menopause, ERalpha level was increased (P = .012) but not cath-D level. According to Mac Neman test, the high-grade DCIS were predominantly ERalpha negative and cath-D positive (P = .0017), and the other CIS were predominantly ERalpha positive and cath-D negative (P = .0002). The 2 markers are overexpressed early in premalignant lesions, but independently. This dissociation suggests a branched model of mammary carcinogenesis involving 1 estrogen-independent pathway with high cath-D and low ERalpha levels (including high-grade DCIS) and 1 estrogen-dependent pathway, with high ERalpha level (including proliferative BBD with atypia and low-grade DCIS). We propose that ERalpha-negative breast cancers may develop directly from high-grade DCIS and that ERalpha assay in preinvasive lesions should be considered in prevention trials with antiestrogens.

[Urogenital amyloidosis: clinico-pathological study of 8 cases]

Amyloidosis of the genito-urinary tract is uncommon. We report 8 cases, often misdiagnosed as a neoplastic process (6/8). Amyloidosis was localized in the bladder (3 cases), in the ureter (1 case) and in the prostate and/or seminal vesicles (4 cases). The amyloid protein was characterized in 7 cases by immunohistochemistry. Among the bladder and ureter amyloidosis, 2 cases were classified as AL lambda amyloidosis and one case as AA amyloidosis in a patient with long history of chronic arthritis. In the fourth case, the deposits could not be identified. Nevertheless an AL amyloidosis might be suggested. Two cases of prostate and/or seminal vesicles amyloidosis were stained with an anti-B2M antibody, in hemodialyzed patients. The 2 others, positive with the anti-Transthyretina antibody, were classified as senile amyloidosis. This small series illustrated the heterogeneous pathogenic types of amyloidosis in the urogenital tract and emphasized the interest of immunohistochemistry to identify the chemical composition of these deposits.

The Mi15 monoclonal antibody (anti-syndecan-1) is a reliable marker for quantifying plasma cells in paraffin-embedded bone marrow biopsy specimens

Plasmocyte selective monoclonal antibodies (MAb) recognizing syndecan-1 have recently been described. They belong to a new cluster, CD138. Using the MAb MI15, we investigated the expression of syndecan-1 in routinely paraffin-embedded tissues. Nontumoral lymph nodes (25 cases) and bone marrow biopsy specimens (63 cases) showed strong membrane staining of plasma cells only, allowing accurate analysis of the nuclear structure. The MI15 positivity correlated with kappa and lambda light chain expression in the cytoplasm. The percentages of plasma cells calculated in bone marrow biopsy specimens after MI15 staining were, respectively, 2.1% (range, 1% to 4%) in normal bone marrows, 8.5% (range, 5 to 17) in reactive plasmocytosis, and 4.66% in monoclonal gammapathy of undetermined significance (MGUS) patients (range, 1 to 13), in the same range but slightly higher than those obtained on smears or on hematoxylin and eosin (H&E)-stained sections. In multiple myeloma (40 cases), all plasma cell types were marked, and Mi15 MAb gave additional information in 8 of 40 (20%) patients. In lymph nodes, Mi15 MAb reacted with Reed-Sternberg cells of classical Hodgkin's disease in 23 of 31 cases (74%) with variable intensity. In contrast, nodular lymphocyte predominance Hodgkin's disease (10 cases), most B cell lymphomas (88 of 107 cases) and all T cell lymphomas (30 cases) were negative. In B cell lymphomas, plasmocytomas (8 cases), plasmocytic lymphomas (2 cases), and 5 of 13 cases of immunoblastic lymphoma with plasmocytoid differentiation were stained. In lymphoplasmocytoid lymphomas (4 lymph nodes and 20 bone marrow biopsy specimens), only mature plasma cells were positive. Moreover, a wide distribution of syndecan-1 was observed in normal and tumoral epithelial tissues. Finally, Mi15 MAb appears to be a reliable marker for identifying and quantifying normal and tumoral plasma cells in paraffin-embedded bone marrow and lymph node samples.

[Sinus histiocytosis (Destombes-Rosai-Dorfman disease) revealed by extranodal spinal involvement]

BACKGROUND

Sinus histiocytosis with massive cervical lymphadenopathy (Rosai-Dorfman disease) is a non-neoplastic lymphoproliferative disorder. Extranodal involvement, especially of the nervous system, is unusual. We report a case revealed by neurological symptoms.

CASE REPORT

A 10-year-old girl presented with paraparesis due to a dural extramedullary mass on magnetic resonance imaging. Massive cervical lymphadenopathy appeared secondarily. Radiological investigations showed mediastinal, paranasal sinus and lower eyelid involvement. The diagnosis of Rosai-Dorfman disease was established histologically and by immunohistochemical studies of nodal lesions by the demonstration of characteristic sinus histiocytosis with sheets of S-100 protein and CD-68 positive large histiocytes displaying lymphocyte phagocytosis. A dramatic response occurred with complete resolution of all clinical findings after treatment with corticosteroids and etoposide, although neurological lesions were unchanged on magnetic resonance imaging.

CONCLUSION

Despite its rarity, this case underlines the unknown pathogenesis of this disease (immune dysfunction?) and the difficulties of treatment (choice of chemotherapeutic agents, duration).

Hepatitis C virus genotypes and quantification of serum hepatitis C RNA in liver transplant recipients. Relationship with histologic outcome of recurrent hepatitis C

The reasons for wide variations in the severity of recurrent hepatitis C after liver transplantation are unclear. We studied liver transplant recipients to assess the effect of hepatitis C virus (HCV) genotype and HCV RNA quantification on histologic progression of recurrent hepatitis C after transplantation. Twenty-five patients underwent transplantation for HCV cirrhosis and were followed up with virologic and histologic assessments for a mean of 51 months. HCV genotype was determined by line probe assay. HCV RNA was quantitated in serum samples by nested polymerase chain reaction. The HCV genotype 1 was detected in 17 patients and other genotypes in 8. Acute lobular hepatitis developed in 17 patients 162 days posttransplantation on average. Long-term biopsy specimens (mean, 51 months after the date of liver transplantation; range, 24-86 months) showed chronic hepatitis in 19 patients (mild, 5; moderate, 9; and severe, 5, 2 with extensive scarring). The serum alanine aminotransferase level was correlated with hepatocyte necrosis (piecemeal and lobular) but not with portal inflammation or fibrosis. Patients infected with genotype 1 had a higher Knodell score, and the 5 patients with severe hepatitis C all were infected with genotype 1. HCV RNA levels were significantly higher in patients with genotype 1 than in patients with other genotypes, as were the severity of histologic recurrence and levels of viral replication.

[Vaginal metastases of breast cancer]

Metastases to the vagina from breast carcinoma are uncommon, and are most often detected during autopsies of patients who have died from a breast cancer or from metastases to the genital tract. A case of symptomatic vaginal metastasis secondary to bilateral breast carcinoma is reported. The potential routes of dissemination include lymphatic and vascular spread. Their respective frequencies vary in the literature. Lymphatic spread in this case is suggested by demonstrable ovarian, myometrial, and lymph node involvement associated with massive submucosal vaginal involvement. This observation of concomitant visceral and lymphatic spread improves our knowledge of metastatic spread from breast cancer to the female genital tract by the lymphatic route.

Increased immunostaining of fibulin-1, an estrogen-regulated protein in the stroma of human ovarian epithelial tumors

Fibulin-1, an extracellular matrix protein, is secreted by human ovarian metastatic cancer cell lines under estrogen stimulation. Fibulin-1 expression was quantified by immunohistochemistry and computer-aided image analysis in 44 human ovarian epithelial tumors and 14 normal ovaries. The fibulin-1 staining intensity in proximal stroma, close to the surface of epithelial cells and tumor cells, progressively increased from normal ovaries to serous carcinomas. In all lesions, excluding cystadenomas, fibulin-1 accumulation was higher in proximal stroma than in distant stroma. In situ hybridization demonstrated strong fibulin-1 gene expression in epithelial cells of serous ovarian carcinomas and some cysts. The weak expression of fibulin-1 RNA in some stromal cells of these tumors could not explain the strong fibulin-1 protein accumulation in tumor stroma, which was therefore mostly produced by tumor epithelial cells. In carcinomas, fibulin-1 staining was not correlated with the percentage of estrogen receptor-alpha (ERalpha)-stained nuclei but was inversely correlated with the progesterone receptor. However, in cystadenomas and borderline tumors, both fibulin-1 and ERalpha protein levels increased, in comparison with normal ovaries, suggesting an effect of estrogens in the early steps of tumorigenesis. This fibulin-1 overexpression, demonstrated in vivo in ovarian carcinomas, might be a useful indicator for predicting cancer risk and/or aggressiveness.

Tophaceous gout of the navicular bone as a cause of medial inflammatory tumor of the foot

A case of tophaceous gout of the navicular bone in a 24-year-old woman is reported. Emphasis is placed on the conditions that might have been precipitating, i.e., anorexia nervosa and alcoholism, and the mechanisms by which increased uric acid level may be explained. The main radiographic patterns of tophaceous gout of the foot are recalled to avoid unnecessary surgery in future cases.

Biotin synthesis in higher plants: purification and characterization of bioB gene product equivalent from Arabidopsis thaliana overexpressed in Escherichia coli and its subcellular localization in pea leaf cells

Biotin synthase catalyses the final step in the biotin biosynthetic pathway and is encoded by the bioB gene in Escherichia coli. To investigate the conversion of dethiobiotin to biotin in the plant kingdom, the cDNA encoding the bioB gene product equivalent from Arabidopsis thaliana was used to construct an E. coli overexpression strain. The purified A. thaliana bioB gene product is a homodimer (100 kDa) with a reddish color and has an absorbance spectrum characteristic of protein with [2Fe-2S] clusters. Its intracellular compartmentation in pea leaves discloses a unique polypeptide of 39 kDa within the matrix of mitochondria.