Fine needle aspiration cytology of primary and metastatic gastrointestinal stromal tumour.

AIM: To explore the cytological spectrum of the gastrointestinal stromal tumour (GIST) including its metastatic sites. MATERIAL AND METHODS: A total of 42 patients (45 sites) diagnosed with GIST or its metastases on fine needle aspiration cytology were studied over a period of 5 years. May-Grünwald Giemsa- and haematoxylin and eosin-stained smears were reviewed and analysed for the cytomorphological spectrum of GIST. RESULTS: Primary GIST alone was seen in 24 cases, E-GIST in eight cases and metastasis in 11 cases (one patient showing metastasis at two distinct sites), whereas concurrent primary and metastatic lesions were noted in two cases. Amongst primary sites, the most commonly affected location was stomach (n = 22), followed by ileum (n = 2), duodenum (n = 1) and rectum (n = 1). Extra-GIST was seen in retroperitoneum and pelvis (n = 3 each), omentum and mediastinum (n = 1 each). Fine needle aspiration cytology was done from 11 metastatic sites of GIST which included liver, gall bladder fossa, chest wall, and thigh. The classic spindle cell arrangement was the predominant cytological pattern. About 8.8% cases showed predominant epithelioid cell morphology and 15.5% cases had a mixed cytomorphology comprising of both spindle cell and epithelioid cell patterns. Nuclear pseudoinclusions, perinuclear vacuoles and multinucleation were seen in four cases. Immunocytochemistry on cell-block sections for confirmation was performed in 18 cases and all these cases showed strong c-KIT positivity. CONCLUSION: In this largest case series of cytomorphological diagnosis of GIST, we describe the cytomorphology and immunocytochemistry of primary and metastatic GIST. GISTs with predominant epithelioid cell morphology may pose a diagnostic dilemma therefore in all suspected cases of GIST, immunocytochemistry for c-KIT and/or DOG1 should be employed on cell-block preparations to confirm the diagnosis of GIST.

Synthesis of C-terminal glycopeptides via oxime resin aminolysis.

Natural glycopeptides have been shown to possess interesting biological activities. In this work, we have developed a general solid-phase approach to C-terminal glycopeptides. Taking advantage of oxime resin ester bond nucleophile susceptibility, we optimised the nucleophilic cleavage step with glycosylamines and demonstrated the generality and scope of this method. In addition, this reaction has high functional group tolerance and can be used for the preparation of longer C-terminal glycopeptides, demonstrated with the synthesis of a glycododecapeptide in one single step. The results pave the way to access efficiently novel medically relevant compounds.

Marcadores tumorales séricos en pacientes asintomáticos / Serum tumour markers in asymptomatic patients

No disponible

Radiosynthesis of the tumor hypoxia marker [18F]TFMISO via O-[18F]trifluoroethylation reveals a striking difference between trifluoroethyl tosylate and iodide in regiochemical reactivity toward oxygen nucleophiles.

The MRI hypoxia marker trifluoromisonidazole (TFMISO) [1-(2-nitro-1H-imidazol-1-yl)-3-(2,2,2-trifluoroethoxy)propan-2-ol] was successfully labeled with (18)F to expand its role into a bimodal PET/MRI probe. (18)F-Labeling was achieved via a three-step procedure in which 2,2,2-[(18)F]trifluoroethyl p-toluenesulfonate prepared by (18)F-(19)F exchange served as the [(18)F]trifluoroethylating agent. The O-[(18)F]trifluoroethylation reaction proceeded efficiently to give the intermediate 1,2-epoxy-3-(2,2,2-[(18)F]trifluoroethoxy)propane, with approximately 60% of (18)F incorporated from the tosylate precursor, which was condensed with 2-nitroimidazole to yield [(18)F]TFMISO. Approximately 40% of the [(18)F]trifluoroethyl tosylate precursor was converted into the final product. In stark contrast, 2,2,2-[(18)F]trifluoroethyl iodide failed to produce [(18)F]TFMISO, giving instead 1,1-[(18)F]difluoro-2-iodoethoxy and 1-[(18)F]fluoro-2-iodovinyloxy analogs of [(18)F]TFMISO. Thus, this investigation has identified 2,2,2-[(18)F]trifluoroethyl tosylate as an excellent [(18)F]trifluoroethylating agent, which can convert efficiently an alcohol into the corresponding [(18)F]trifluoroethyl ether.

Synthesis and structural characterization of the peptide epitope of the ovarian cancer biomarker CA125 (MUC16).

A highly conserved region of 21 amino acids flanked by cysteine residues, contained within a larger repeated domain, has been proposed to be the antibody-binding site in the ovarian cancer biomarker CA125 (MUC16). In this study solid-phase peptide synthesis with Fmoc protection chemistry was used to assemble a 21-mer peptide corresponding to the most frequently occurring antibody binding sequence in CA125. Potentially significant sequence variants were also synthesized. Peptide secondary structure was investigated using Fourier transform infrared spectroscopy, revealing the consensus sequence peptide to be largely unstructured at physiological pH whether the cysteine residues were reduced or were oxidized to form an intramolecular disulfide bond. Substitution of serine for proline at position 8 (P8S) results in ß-sheet formation in peptides involved in intramolecular disulfide bonds. This ß-sheet structure does not persist in peptides incapable of intramolecular disulfide bonding because of sequence nor in peptides treated with the reducing agent dithiothreitol. In CA125, P8S is predicted to occur in ∼25% of repeat domains, suggesting that this structural motif is a non-negligible contributor to overall structure and function. These findings suggest that future structural characterization efforts of CA125 should be especially mindful of the amino acid sequence and oxidation state of the protein.

Synthesis, radiofluorination, and hypoxia-selective studies of FRAZ: A configurational and positional analogue of the clinical hypoxia marker, [18F]-FAZA.

The current work evaluates 1-alpha-d-(2-deoxy-2-fluororibofuranosyl)-2-nitroimidazole (FRAZ), a novel azomycin nucleoside that is a potential radiosensitizer of tumor hypoxia. FRAZ is a ribose analogue of 1-alpha-d-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole ([(18)F]-FAZA), a clinically used hypoxia marker. Preliminary assessment of the cytotoxicity and hypoxia-specific in vitro binding in HCT-110 colorectal cancer cells indicate that the radiosensitization properties of FRAZ are similar to that of FAZA, with a sensitizer enhancement ratio (SER) of approximately 1.8. An automated radiosynthesis of [(18)F]-FRAZ using a commercial automated synthesis unit (ASU) was established (synthesis time approximately 32 min; radiochemical yield (decay uncorrecetd) approximately 22%) to facilitate its application in PET-based diagnosis of hypoxic tumors.

Design, synthesis, and characterization of fluorescent cobalamin analogues with high quantum efficiencies.

Cobalamin tethered to fluorescein or Rhodamine 6G has been synthesized and characterized. The fluorophore is conjugated to the ribose-5'-OH of cobalamin through a rigid linker to prevent the fluorophore from folding back through space and interacting with the corrin ring of cobalamin. This increases the fluorescence quantum yield. This new family of cobalamin analogues may be suitable for use as tumor markers to tag cancer cells for surgical resection.

Variabilidad de las concentraciones séricas de CA 125 en mujeres sanas en función de la edad, situación hormonal y otras condiciones / Variability of CA 125 serum concentrations in healthy women according to age, hormonal status and other factors

Los conocimientos relativos a los factores que influyen en las concentraciones de CA 125 ha conducido a cuestionarse la validez de un único valor límite. Los objetivos del trabajo fueron valorar los valores de CA 125 en función de la edad, presencia o ausencia de menopausia, índice de masa corporal (IMC), hábito tabáquico, paridad, variabilidad durante el ciclo menstrual, variabilidad biológica, índice de individualidad y diferencia crítica. Se incluyó a 65 mujeres sanas distribuidas en 2 grupos: sin y con menopausia. Los principales resultados demuestran que existe una clara relación entre las concentraciones de CA 125 y la edad, que en mujeres sin menopausia la concentración de CA 125 fue superior respecto a las mujeres con menopausia, con p95 de 30,52 y 18,30 U/ml, respectivamente. No encontramos variaciones durante el ciclo menstrual, aunque existe la probabilidad de encontrar valores superiores al valor límite convencional durante la fase folicular. La variabilidad biológica intra e interindividual en mujeres sin menopausia fue del 14,23 y el 43,57%, respectivamente, mientras que la variabilidad biológica interindividual en mujeres con menopausia fue del 36,25%. La diferencia crítica fue del 42,73% y el índice de individualidad de 0,11. No encontramos diferencias en función de la paridad ni del hábito tabáquico. Tampoco encontramos una relación respecto al IMC. En conclusión, el conocimiento de factores que influyen en las concentraciones séricas de CA 125, así como la adaptación de valor límite en función de diferentes situaciones fisiológicas y clínicas puede permitir una mejor interpretación e identificación de subgrupos con un riesgo de presentar cáncer de ovario (AU)

Knowledge of the factors influencing serum concentrations of CA 125 have led the validity of a single cut-off value to be questioned. The aims of the present study were to evaluate CA 125 levels according to age, menopause, body mass index (BMI), smoking, parity, variability during the menstrual cycle, biological variation, index of individuality (II), and critical difference (CD). Sixty-five healthy women distributed in 2 groups, non-menopausal and menopausal, were included. The main results of the study demonstrate that there is a clear relationship between CA 125 levels and age: serum levels of CA 125 were significantly lower in menopausal women than in non-menopausal women, with 95th percentiles of 30.52 U/ml and 18.30 U/ml, respectively. No variations were found during the menstrual cycle, although a CA 125 value higher than the conventional cut-off value was observed during the follicular phase. In non-menopausal women, intra- and interindividual biological variations were 14.23% and 43.57%, while in menopausal women interindividual biological variation was 36.25%. CD was 42.73% and II was 0.11. No significant differences were found between smokers and nonsmokers or according to parity. No relationship was found between CA 125 levels and BMI. In conclusion, knowledge of the factors influencing serum concentrations of CA 125 according to different physiologic and clinical factors and careful adjustment of cut-off values could improve interpretation and identification of subgroups at risk for ovarian carcinoma (AU)

Diagnosing lymphoproliferative disorders involving the cerebrospinal fluid: increased sensitivity using flow cytometric analysis.

Flow cytometric immunophenotypic analysis (FCA) can be performed to evaluate lymphoid cells in cerebrospinal fluid (CSF). We compared this method with conventional cytologic diagnosis to determine its utility. A retrospective comparison of 35 consecutive CSF flow cytometry results with the corresponding cytologic diagnoses was undertaken. Twenty-five of 35 CSFs (71%) were successfully analyzed by flow cytometry. The 10 samples which could not be analyzed were either too old (greater than 3 days) or had an insufficient number of cells. A total of 9 lymphomas was detected: 4 by both flow cytometry and cytology; 2 by cytology alone; and 3 by flow cytometry alone. This represents a 50% increase in the detection of lymphoproliferative disorders in CSF by a combination of flow cytometry and cytology vs. cytology alone. Furthermore, in 3 cases with follow-up where the cytologic diagnosis was "atypical cells of undetermined significance" and the flow cytometric findings were negative for malignancy, the clinical course confirmed a benign pleocytosis in all three. We conclude that flow cytometric analysis markedly improves sensitivity when used in combination with cytology in the evaluation of lymphoid cells in CSF.

Receptor-mediated targeting of 67Ga-deferoxamine-folate to folate-receptor-positive human KB tumor xenografts.

The radiochemical synthesis and stability of 67Ga-deferoxamine-folate ([67Ga]Ga-DF-Folate) were examined as a function of DF-Folate concentration. Optimal labeling occurred at DF-Folate concentrations > or =2.5 microg/mL. To define the possible biological significance of variations in product formulation, the biodistribution of [67Ga]Ga-DF-Folate was examined as a function of administered deferoxamine-folate dose in an athymic mouse KB tumor model. The folate-receptor-positive KB tumors were found to concentrate the 67Ga radiolabel in a dose-dependent fashion, consistent with saturable involvement of the folate receptor in mediating tumor accumulation of the radiopharmaceutical.

Synthesis of alpha- and beta-biotinylated T-antigen.

The T-antigen [beta-D-Gal-(1-->3)-D-Ga1NAc] has been linked to biotin through a C6 spacer arm for the detection of a specific 'T-antigen-lectin' complex at the surface and/or on the migration pathway of melanoma cells. When 4,6-di-O-acetyl-2-azido-2-deoxy-3-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-alpha- or -beta-D-galactopyranosyl halides were treated with N-benzyloxycarbonyl or N-fluorenylmethoxycarbonyl protected aminohexanols (used as the spacer arm), unusual stereoselectivities were observed for the synthesis of the alpha and beta anomers. The synthesis of the alpha anomer could only be achieved, in reasonable yields, with the Schiff base of aminohexanol.