Diagnosis of metastases from testicular germ cell tumours using fine needle aspiration cytology.

The cytological features of testicular germ cell tumours were established in smears from 15 freshly resected tumours. These features were applied to the fine needle aspiration cytology diagnosis of metastases in 27 patients referred for chemotherapy. There were 16 positive reports in 32 aspirates of which 13 were taken before chemotherapy and three in patients with residual or new masses after chemotherapy. Teratomas and typical seminomas showed certain characteristic morphological features in cytological preparations which when present in fine needle aspiration cytology material enabled tumour types to be diagnosed. Spermatocytic and anaplastic seminoma were not represented in this series. It is unlikely that these could be distinguished from malignant teratoma undifferentiated (MTU) in the fine needle aspiration cytology material. Metastases from carcinomatous areas in MTU and malignant teratoma intermediate (MTI) may not be distinguishable in fine needle aspiration cytology material from metastatic adenocarcinoma or undifferentiated carcinoma from a different primary site. Positive cytological findings are of value to the oncologist in the management of patients with metastases from testicular germ cell tumours; negative cytology does not exclude the presence of viable tumour. The sampling of small foci of viable tumour in large necrotic masses persisting after chemotherapy is a problem for radiologists, cytologists, and histopathologists. This paper does not advocate the use of fine needle aspiration cytology for the diagnosis of primary testicular tumour.     

Inhibition of CDK activity and PCNA-dependent DNA replication by p21 is blocked by interaction with the HPV-16 E7 oncoprotein

p21 inhibits cyclin-dependent kinase (CDK) activity and proliferating cell nuclear antigen (PCNA)-dependent DNA replication by binding to CDK/cyclin complexes and to PCNA through distinct domains. The human papillomavirus (HPV)-16 E7 oncoprotein (16E7) abrogated a DNA damage-induced cell cycle arrest in vivo, despite high levels of p21. Using cell lysates and purified proteins we show that 16E7 prevented p21 both from inhibiting CDK2/cyclin E activity and PCNA-dependent DNA replication, whereas the nononcogenic HPV-6 E7 had reduced effects. Inactivation of both inhibitory functions of p21 was attained through binding between 16E7 and sequences in the carboxy-terminal end of p21 that overlap with the PCNA-binding site and the second p21 cyclin-binding motif. These data imply that the carboxyl terminus of p21 simultaneously modulates both CDK activity and PCNA-dependent DNA replication and that a single protein, 16E7, can override this modulation to disrupt normal cell cycle control.     

Age-related accumulation of ceroid-like pigment in mice with Chediak-Higashi syndrome.

The Chediak-Higashi Syndrome (CHS) is a rare inherited disorder occurring in man and several animal homologs including the beige mouse; it is characterized by pigmentary dilution, susceptibility to pyogenic infections, and the presence of enlarged lysosomes in many cell types. Beige mice 6 months of age and older were found to have darkened livers, kidneys, and spleens, accompanied by splenomegaly. A fluorescence microscopic survey of tissues from beige mice revealed marked accumulations of a microscopic survey of tissues from beige mice revealed marked accumulations of a yellow autofluorescent pigment inhepatocytes, renal proximal tubule cells, and splenic macrophages. Additionally, large amounts of hemosiderin were present in the spleen. In beige mice, the pigment was noted in animals as young as 1 to 2 weeks of age and gradually increased in amount as the animals aged. A histochemical investigation of the pigment showed that it was ceroid-like in nature and contained in lysosomes. Ultrastructurally, the pigment was composed of lipid-like droplets embedded in a dense matrix and surrounded by a limiting membrane. The accumulation of ceroid-like material in beige mice may be a reflection of the metabolic disturbance which underlies CHS.     

A Hereditary Alteration in Kidneys of Mice with Chediak-Higashi Syndrome

The beige mouse is considered to be a homologue of Chediak-Higashi syndrome (CHS). Cytochemical and electron microscopic studies have revealed an inherited lesion in the kidneys of these mice. The alteration was confined to the distal segments (S3) of the proximal tubules and was characterized by the accumulation of numerous massive polysaccharide-rich granules. These granules were reactive for acid phosphatase and β-glucuronidase activities and were therefore considered to be lysosomes. Small numbers of lymphocytes were also observed in the perivascular spaces and within the tubules of the S3 segment. The fine structure of S3 cells was also markedly altered. In addition to the massive lysosomes, dense material was found associated with the brush border and was present in pinocytotic vesicles at the base of the brush border and between basal invaginations of the plasma membranes. Despite these changes, reabsorption of exogeneous peroxidase by S3 cells appeared to be normal. The presence of a congenital defect in the kidney of the beige mouse appears to provide a useful model for studying the morphology and function of the S3 region of the nephron.     

Genetic and cytological characterization of the RecA-homologous proteins Rad51 and Dmc1 of Schizosaccharomyces pombe

The Schizosaccharomyces pombe rad51⁺ and dmc1⁺ genes code for homologues of the Escherichia coli recombination protein RecA. Deletion of rad51⁺ causes slow growth, retardation of cell division and a decrease in viability. rad51 cells have a defect in mating-type switching. The DNA modification at the mating-type locus required for mating-type switching contributes to slow growth in the rad51 mutant. Cell mating is reduced in crosses homozygous for rad51. Ectopic expression of the dmc1⁺ gene allowed us to demonstrate that the reduction in meiotic recombination in dmc1 mutants is not caused by a disturbance of rad24 expression from the dmc1-rad24 bicistronic RNA. We describe the functional defects of terminally epitope-tagged Dmc1 and Rad51 and discuss it in terms of protein interaction. Presumptive Rad51 and Dmc1 foci were detected on spreads of meiotic chromatin.     

Corticoliberin, somatocrinin and amine contents in normal and parkinsonian human hypothalamus

We have compared hypothalamic contents of various neurotransmitters (dopamine (DA), norepinephrine and serotonin) and their metabolites (dihydroxyphenyl acetic acid, homovanilic acid, 5-hydroxyindoleacetic acid) in post-mortem human controls and parkinsonian hypothalami. Neurotransmitters and their metabolites were measured in 0.1 N HCl hypothalami extracts using electrochemical detection after high performance liquid chromatography. Using specific radioimmunoassays we have also measured corticoliberin and somatocrinin contents in these hypothalami. Despite a 50% decrease of DA contents in parkinsonian hypothalami, no variations of corticoliberin and somatocrinin contents were found: 16.6 +/- 1.78 pg/mg tissue in Parkinson disease vs 16.71 +/- 1.89 in controls for human corticotropin-releasing factor (hCRF 1-41) and 37.38 +/- 11 vs 45.16 for human growth-hormone-releasing factor (hGRF 1-44).     

Thrombopoietin receptor (Mpl) expression by megakaryocytes in myeloproliferative disorders

The thrombopoietin receptor (Mpl) is involved in the pathogenesis of chronic myeloproliferative disorders (CMPD). In this study, we determined Mpl expression by bone marrow cells and megakaryocytes in CMPD by applying laser microdissection, real-time RT-PCR, and immunohistochemistry. Mpl mRNA expression was significantly increased up to 9-fold in total bone marrow cells (p < 0.001) and up to 4-fold in megakaryocytes in chronic myeloproliferative disorders (n = 73) compared to normal controls (n = 26, p = 0.01). Immunohistochemistry revealed heterogeneous Mpl expression by megakaryocytes in CMPD with a stronger accentuation in idiopathic myelofibrosis (IMF) in comparison to polycythaemia vera (PV) and essential thrombocythemia (ET). In addition to megakaryocytes, the erythropoietic lineage was prominently labelled by Mpl antiserum, with considerably stronger staining in polycythaemia vera. We conclude that, in CMPD, megakaryocytes and erythroid cells exhibit increased Mpl expression levels which may contribute to the sustained proliferation of both cell lineages in CMPD.     

Giant ragweed specific immunotherapy is not effective in a proportion of patients sensitized to short ragweed: analysis of the allergenic differences between short and giant ragweed

BACKGROUND: Short ragweed and giant ragweed pollen allergens are considered largely cross-reactive, and it is generally believed that 1 species is sufficient for skin testing and immunotherapy. However, in the area north of Milan (a zone widely invaded only by short ragweed), about 50% of patients submitted to injection specific immunotherapy with giant ragweed showed little or no clinical response, but showed an excellent outcome if they were shifted to short ragweed specific immunotherapy. OBJECTIVE: To investigate allergenic differences between short and giant ragweed. METHODS: IgE reactivity to short ragweed of sera from 16 patients allergic to ragweed was assessed by immunoblot before and after absorption with short and giant ragweed. Moreover, 41 ragweed-monosensitive patients underwent skin prick test with both ragweed species. RESULTS: In several cases, preabsorption of sera with giant ragweed extract was unable to inhibit IgE reactivity fully against both a 43-kd allergen and other allergens at different molecular weights in short ragweed. On skin prick test, short ragweed induced larger wheals than giant ragweed in the majority of patients, and 6 of 41 (15%) patients were strongly short ragweed-positive but giant ragweed-negative. The immunoblot with the serum from 1 of these subjects showed a strong IgE reactivity to short ragweed at about 43 kd in the absence of any reactivity to giant ragweed. CONCLUSION: Short and giant ragweed are not allergenically equivalent. Allergenic differences involve both the major allergens Amb a 1-2/Amb t 1-2 and some minor allergens. In patients allergic to ragweed, both diagnosis in vivo and immunotherapy should always be performed by using the ragweed species present in that specific geographic area.     

Epidemiology of extended-spectrum beta-lactamase-producing Enterobacter isolates in a Spanish hospital during a 12-year period

Fifteen Enterobacter clinical isolates (11 Enterobacter cloacae isolates, 3 Enterobacter aerogenes isolates, and 1 Enterobacter gergoviae isolate), representing 0.4% of all Enterobacter isolates recovered in our hospital from 1989 to 2000, were suspected of harboring an extended-spectrum beta-lactamase (ESBL). These isolates were recovered from 14 different patients. ESBLs were transferred by conjugation into an Escherichia coli recipient strain. Pulsed-field gel electrophoresis (PFGE) revealed a single clone of E. aerogenes and six different clones of E. cloacae. Four of these E. cloacae clonal types were represented by only one isolate each, but the other two were represented by three and four isolates, respectively. Isoelectric focusing, susceptibility phenotyping, PCR analysis, and sequencing demonstrated the presence of three different ESBLs. The most frequent was the recently characterized CTX-M-10 ESBL, which was found in the E. gergoviae isolate and in all but one of the E. cloacae isolates. The remaining E. cloacae isolate harbored a TEM-27 ESBL, and the three E. aerogenes isolates harbored a TEM-24 ESBL. PFGE revealed that our E. aerogenes strain was indistinguishable from the French TEM-24-producing E. aerogenes endemic clone. Although a low prevalence of ESBL-producing Enterobacter isolates was found in our institution over a 12-year period, a diversity of nonepidemic E. cloacae clones was detected, as was the persistence of the CTX-M-10 beta-lactamase. The presence of the TEM-24-producing E. aerogenes French clone in our institution also demonstrates the intercountry dissemination of ESBL-producing isolates.