Cytodiagnosis of metastatic amelanotic melanomas by fine-needle aspiration biopsy: adjunctival value of immunocytochemistry and electron microscopy

BACKGROUND

The cytologic diagnosis (CD) of metastatic amelanotic melanomas (MAM) is challenging because the tumor cells may mimic those of a carcinoma or a sarcoma in cytologic materials obtained by fine-needle aspiration biopsy (FNAB).

METHODS

Thirty-five well documented cases of MAM at different anatomic sites with cytologic evaluation by FNAB were reviewed.

RESULTS

In 31 cases a correct CD was made based on the cytologic and immunocytochemical (IM) findings. The MAMs were characterized by abundant dyshesive pleomorphic malignant cells containing prominent nucleoli and occasional intranuclear cytoplasmic inclusions. The tumor cells stained positively with S-100 and/ or HMB-45 antibodies. There were four cases with unusual cytologic manifestations and equivocal IM characteristics requiring electron microscopic examination (EME) of the aspirated tumor cells to identify intracytoplasmic melanosomes, pre-melanosomes, or microtubules within cisternae of rough endoplasmic reticulum (MCRER) to establish a diagnosis of MAM.

CONCLUSIONS

A correct CD of MAMs may be made in a large number of cases by routine cytologic findings and IM staining with S-100 protein and HMB-45 antibodies. However, EME is necessary to demonstrate melanosomes, premelanosomes, or MCRER in cases with unusual cytologic and equivocal IM manifestations.

[Detection of MDM 2 and p 53 genes in rhabdomyosarcoma by in situ hybridization]

OBJECTIVE

To observe the correlation between MDM2, p53 genes and the pathogenesis, clinical pathology and prognosis in rhabdomyosarcoma (RMS).

METHODS

Thirty one cases of MRS with follow-up history were covered for this study. MDM2 and p53 genes were detected by digoxigenin labeling in situ hybridization-technique.

RESULTS

The positive rates for MDM2 and p53 genes were 77.4% (24/31) and 66.7% (21/31) respectively, regardless of age, sex and the histological typing of RMS, but there was remarkable difference in the positive rates and intensity between the well and poorly differentiated cases, metastatic and non-metastatic cases as well as one year and three years survival period (P < 0.05).

CONCLUSIONS

The detection of MDM2 and p53 gene is considered valuable in evaluating the malignant degree, predictable metastasis and prognosis of RMS.

The methanogenic archaeon Methanosarcina thermophila TM-1 possesses a high-affinity glycine betaine transporter involved in osmotic adaptation

Methanogenic Archaea are found in a wide range of environments and use several strategies to adjust to changes in extracellular solute concentrations. One methanogenic archaeon, Methanosarcina thermophila TM-1, can adapt to various osmotic conditions by synthesis of alpha-glutamate and a newly discovered compatible solute, Ne-acetyl-beta-lysine, or by accumulation of glycine betaine (betaine) and potassium ions from the environment. Since betaine transport has not been characterized for any of the methanogenic Archaea, we examined the uptake of this solute by M. thermophila TM-1. When cells were grown in mineral salts media containing from 0.1 to 0.8 M NaC1, M. thermophila accumulated betaine in concentrations up to 140 times those of a concentration gradient within 10 min of exposure to the solute. The betaine uptake system consisted of a single, high-affinity transporter with an apparent K3 of 10 microM and an apparent maximum transport velocity of 1.15 nmol/min/mg of protein. The transporter appeared to be specific for betaine, since potential substrates, including glycine, sarcosine, dimethyl glycine, choline, and proline, did not significantly inhibit betaine uptake. M. thermophila TM-1 cells can also regulate the capacity for betaine accumulation, since the rate of betaine transport was reduced in cells pregrown in a high-osmolarity medium when 500 microM betaine was present. Betaine transport appears to be H+ and/or Na+ driven, since betaine transport was inhibited by several types of protonophores and sodium ionophores.

A comparative study on morphology and immunohistochemistry of rhabdomyosarcoma and embryonal skeletal muscles

OBJECTIVE

To investigate the histologic and histogenetic relationship between various types of rhabdomyosarcomas (RMS) and embryonal skeletal muscle (ESM) for further understanding of the histogenesis, classification and pattern of differentiation of RMS.

METHODS

Fifty cases of variant types of RMS and 20 cases of ESM at different gestational ages were available. All specimens were stained with HE, PAS, Van Gieson, Masson, phosphotungstic acid hematoxilin and with antibodies for the demonstration of vimentin, desmin, HHF-35 and myoglobin by ABC method.

RESULTS

The results showed that the order of positive expression and the intensity of positive reaction of the different immunohistochemical staining were consistent with the degree of differentiation of the tumor and the development of the ESM. It is obvious that each type of RMS is composed of tumor cells in different degree of differentiation and is derived from primitive mesodermal cells which are capable of potential differentiation towards mature skeletal muscles.

CONCLUSIONS

Based on the results of this study, an ideal histologic classification of RMS should reflect not only the cell morphology and histologic structures but also the degree of differentiation of the tumor cells.

[The correlation between expression of oncogene protein products p53, p21, p185 and cell differentiation and prognosis in rhabdomyosarcoma]

OBJECTIVE

To study the correlation between expression of oncogene protein products p53, P21, p185 and histological type, cell differentiation and prognosis in rhabdomyosarcoma (RMS).

METHODS

41 RMS cases which had follow-up material were selected for this study. Expression of protein products of oncogene p53, p21 and p185 were synchronously detected and compared by immunohistochemical ABC method.

RESULTS

The positive rates for p53, p21 ras and P185 c-erbB-2 were 72%, 68% and 60% respectively. Positive expression did not relate to age, sex or RMS histological type, but related to the degree of RMS differentiation. The positive rate of p53 ad p21 ras in well differentiated cases were 42.9% and 28.6% while that of the poorly differentiated group was 85% and 80% respectively (P < 0.05). The psoitive rate of p53 in the RMS group with metastasis was 86.6%, significantly higher than that of the non-metastasized group, which was 66.7% (P < 0.05). There was a significant difference between those with one year survival, whose p52 positive rate was 86.7% and those who survived for more than 3 years, whose p53 positive rate was 47.1% (P < 0.05).

CONCLUSION

The results suggest that the irregular expressions of p53 and p21 were related to tumor differentiation and the degree of malignancy. p53 positivity may indicate a poor prognosis.

[A clinicopathological study of small-cell esophageal carcinoma]

Small-cell esophageal carcinoma (SCEC) is not uncommon. From 1979 through 1994, 42 cases of SCEC were diagnosed among 711 patients with cancer of the esophagus, with a relative frequency of 5.9%. Differential diagnosis is difficult according to clinical symptoms and signs. However, SCEC differs greatly from squamous-cell carcinoma of the esophagus in histopathology and biologic behavior but is similar to small-cell lung cancer (SCLC). Surgical treatment alone of SCEC patients has a mean survival period of 11.2 months while patients treated with radiotherapy alone has a longer survival (22.8 months). No case was treated only with chemotherapy in this group of patients. Those received no treatment could survive 6.2 months only. Therefore, SCEC is a very aggressive tumor with poor prognosis. Histochemical and immunohistochemical study revealed both epithelial and neuro-endocrine differentiation potentials suggesting that SCEC probably originates from mulfipotential primitive stem cells in the esophageal mucosa.

Mutant p53 expression in kidney tubules adjacent to renal cell carcinoma: evidence of a precursor lesion

Neoplastic transformation can be associated with mutations of the p53 gene. This leads to stabilization of its protein product and to its accumulation, which allows immunohistochemical detection. Mutant p53 expression has been seen in many neoplasms, including renal cell carcinoma (RCC). We recently described putative precursor lesions of RCC. The lesions were defined as intratubular epithelial dysplasia (IED) of kidney tubules adjacent to RCC. They were seen in one-third of the cases studied. The findings were based only on light microscopic analysis. We hypothesized that neoplastic transformation would be manifested by mutant p53 expression in the kidney tubules adjacent to RCC and not in nonneoplastic kidneys. Immunohistochemical staining for p53 in 24 cases of RCC with adjacent kidneys was performed. We used the DO-7 monoclonal antibody reactive for the N-terminal of the p53 protein on formalin-fixed paraffin-embedded tissue. Sections from 14 kidneys resected for nonneoplastic conditions were used as controls. Twenty-one (87%) of the 24 cases of RCC had nuclear p53 expression in the tumor cells. This included 14 cases (58%) with intense reactivity and 7 cases (29%) with weaker p53 immunoreactivity. Of the 24 cases of RCC, IED was identified in 13 cases (54%). Immunoreactivity for p53 was focally seen in tubules of all the lesions, as well as in the nonlesional areas. Six of the lesions exhibited intense nuclear staining. The kidneys adjacent to the RCC, with no evidence of IED, showed focally intense positive p53 nuclear staining in four cases. None of the control specimens showed p53 expression. Our findings provide supportive evidence that previously described IED in kidneys adjacent to RCC are most likely precursor lesions of the neoplasm. Aberrant expression of p53 in areas without evidence of IED may suggest that neoplastic transformation manifested by p53 mutation in kidney tubules may be seen before the development of the morphologic features of dysplasia and malignancy.

CD45 (leucocyte common antigen) expression in T and B lymphocyte subsets

CD45 is the dominant tyrosine phosphatase in haematopoietic cells and can modulate the effects of many other signaling molecules by dephosphorylation. The extracellular portion of CD45 has considerable variability due to differential splicing and glycosylation. This may allow for interactions with a variety of ligands expressed on interacting cells or on the same cell surface. Monoclonal anti CD45 antibodies that are reactive with epitopes that result from differential splicing and glycosylation can distinguish between cell populations that differ in maturation and function. These reagents can be used in the immunophenotyping of hematopoietic malignancies as well as in immunodeficiencies and autoimmune diseases. Several studies have shown that different anti CD45 reagents have different activating or inhibiting effects in vitro on a variety of T and B cell activation events. There are some indications that anti CD45 reagents can also selectively modify lymphocyte function in vivo. Such applications could potentially allow for the selective upregulation and down regulation of lymphocyte functions in a variety of immunologically mediated diseases.

Modulation of insulin action by vanadate: evidence of a role for phosphotyrosine phosphatase activity to alter cellular signaling

A number of vanadium compounds (vanadate, vanadyl sulfate, metavanadate) have insulin-mimicking actions both in vitro and in vivo. They have multiple biological effects in cultured cells and interact directly with various enzymes. The inhibitory action on phosphoprotein tyrosine phosphatases (PTPs) and enhancement of cellular tyrosine phosphorylation appear to be the most relevant to explain the ability to mimic insulin. We demonstrated that in rat adipocytes both acute insulin effects, e.g. stimulation of IGF-II and transferrin binding and a chronic effect, insulin receptor downregulation, were stimulated by vanadate. Vanadate also enhanced insulin binding, particularly at very low insulin concentrations, associated with increased receptor affinity. This resulted in increased adipocyte insulin sensitivity. Finally vanadate augmented the extent of activation of the insulin receptor kinase by submaximal insulin concentrations. This was associated with a prolongation of the insulin biological response, lipogenesis, after removal of hormone.

IN CONCLUSION

in rat adipocytes vanadate promotes insulin action by three mechanisms, 1) a direct insulin-mimetic action, 2) an enhancement of insulin sensitivity and 3) a prolongation of insulin biological response. These data suggest that PTP inhibitors have potential as useful therapeutic agents in insulin-resistant and relatively insulin-deficient forms of diabetes mellitus.

Postnatal changes of CD45 expression in peripheral blood T and B cells

One known postnatal change of CD45 expression is the decline of the CD45RAhigh CD45ROlow T subsets and the reciprocal increase of the CD45RAlow CD45ROhigh T subsets in the peripheral blood. Using a panel of monoclonal antibodies reactive with either protein or carbohydrate epitopes on the variable regions of CD45, we were able to detect more postnatal changes of CD45 expression. These changes are largely caused by modulation of the CD45 glycosylation, including: (1) lesser sialylation of the CD45RA region on T cells, and (2) differential sialylation of the CD45RB region leading to the distinction of CD45RBhigh and CD45RBlow T and B subsets. In addition, the existence of the CD45RAdim CD45ROdim labelled as transitional T cells is only found during the postnatal life. These changes may reflect the maturation of the immune system.

Psychological implications and acceptability of preimplantation diagnosis

The aim of this study was to ascertain the degree of acceptability of preimplantation diagnosis with blastocentesis in 180 women at risk for beta-thalassaemia awaiting chorionic villus sampling (CVS). The women were asked to fill in a questionnaire some days before sampling. All women who had had previous therapeutic abortion found blastocentesis acceptable. Only 30% of women who had not had previous therapeutic abortion chose blastocentesis, whilst 25% of primigravid women opted for blastocentesis. From these preliminary data it seems that obstetric experience is an important factor in the reproductive choice of women at high genetic risk.