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Biomedical subjects

R Lai

Publications and source records attributed to R Lai.

At least 73 records · Page 4Linked to original sources
PubMed1999

[Fertilization in vitro and microinsemination. 6 years of experience in the Ospedale Microcitemico of Cagliari].

BACKGROUND: In this study the results of six years experience (1993-1998) in IVF, ICSI and assisted hatching on 442 sterile couples for a total of 868 cycles are reported. Since 1997 ICSI has also been carried out in cases of azoospermia extracting mobile spermatozoa from the epididymal (MESA) or from the testicle (TESE). METHODS: Ages ranged from 20 to 48 and mean years sterility was 5.868 cycles were carried out of which 153 (17.62%) were for IVF, 705 (81.22%) for ICSI and 10 (1.15%) for MESA and TESE. Assisted hatching was performed through "partial zona dissection" in 329 cases on a total of 987 embryos. RESULTS: The pregnancy rates per embryo transfer in IVF and ICSI cycles were 22.4 and 19.96% respectively. Results considering patients age were: 33.87% below 35, 29.55% between 35 and 38 and 6.60% above 38. In the group of 189 assisted hatching patients the evolutive pregnancy rate rose from 15.78 to 26.40% and multiple pregnancies from 28.63 to 42%. CONCLUSIONS: ICSI has offered high rates of fertilization and pregnancy even in extreme cases of oligoasthenospermia or cases of azoospermia adopting MESA or TESE techniques. A decisive factor on pregnancy rates is age, very low over 38 years. Assisted Hatching further increased the pregnancy rates.

Adult↗
PubMed1998

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.

Antibodies, Neoplasm↗
PubMed1998

Contributions of the entorhinal cortex, amygdala and hippocampus to human memory.

Recent studies have indicated that, in the monkey, the rhinal cortex (consisting of the entorhinal and perirhinal cortices) is more important to visual recognition memory than the hippocampus or amygdala. The present study investigated the role of the entorhinal cortex in humans using memory scores from surgical epilepsy patients classified according to their mesial temporal lobe pathology. The temporal lobe removals included 4-5 cm of neocortex, amygdala, rhinal cortex and 2-3 cm of the hippocampus and parahippocampal gyrus. Compared to autopsied control subjects, all of the patients showed significant gliosis in the amygdala, but they differed as to whether or not there were entorhinal and/or hippocampal abnormalities. Both preoperatively and one or more years postoperatively, the patients performed tests of verbal recall (Wechsler Memory Scale Logical Memory), visual recall (Rey Figure), verbal recognition and visual recognition (Warrington Recognition Memory Test: Words and Faces, respectively). Preoperatively, patients with hippocampal pathology showed deficits in visual recall. Postoperatively, a significant drop in verbal and visual recall was seen only for patients who lost intact hippocampal tissue, irrespective of the condition of the excised entorhinal cortex. Together, the results argue that the hippocampus is more important than the entorhinal cortex for the recall of newly learned information.

Adolescent↗
PubMed1998

[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.

Adolescent↗
PubMed1998

Immunohistochemical detection of E2F-1 in non-Hodgkin's lymphomas: a survey of 124 cases.

E2F-1 is a transcription factor that mediates cell cycle progression from the G1 to S phase and is normally regulated by a group of proteins, including cyclin D1. Although deregulation of E2F-1 is implicated in neoplastic transformation, in situ examination of this protein has not been performed to date. Using an immunohistochemical technique applied to routinely fixed, paraffin-embedded tissue sections, we evaluated E2F-1 expression in reactive lymphoid tissues and in 124 cases of non-Hodgkin's lymphoma (NHL) of various types. In reactive lymphoid tissues, E2F-1 was expressed predominantly by large noncleaved cells in germinal centers and by a small subset of cortical thymocytes. Mantle zones and splenic marginal zones were negative. Among the NHLs, four types had a relatively high percentage (> 20%) of E2F-1-positive cells: mantle cell lymphoma (19 of 19), lymphoblastic lymphoma (5 of 5), small noncleaved cell lymphoma (4 of 6), and hepatosplenic gammadelta T-cell lymphoma (3 of 3). The consistent detection of many E2F-1-positive cells in mantle cell lymphoma is in contrast to other small B-cell NHLs (n = 29), which had relatively few (< 10%) E2F-1-positive cells. This finding suggests that immunohistochemical staining for E2F-1 as a supplement to the existing markers, such as cyclin D1, might be useful in the differential diagnosis of NHLs composed of small B cells.

Carrier Proteins↗
PubMed1998

Expression of the cell-cycle-related proteins E2F-1, p53, mdm-2, p21waf-1, and Ki-67 in multiple myeloma: correlation with cyclin-D1 immunoreactivity.

Approximately 30% of multiple myelomas (MMs) express cyclin D1 when assessed using immunohistochemical techniques. Cyclin D1 expression correlates with greater tumor burden in MM, because cyclin D1-positive cases are more frequently associated with extensive bone marrow involvement, i.e., high pathologic stage, than are cyclin D1-negative cases. The mechanisms that explain this association are unknown. To explore other differences between cyclin D1-positive and cyclin D1-negative MMs, we assessed 59 MMs immunohistochemically for several G1 cell-cycle regulatory proteins, including cyclin D1, E2F-1, p53, mdm-2, and p21waf-1, using routinely fixed and processed, paraffin-embedded bone marrow specimens. Twenty MMs (34%) were cyclin D1 positive, and 39 (66%) were cyclin D1 negative. Eighteen (90%) of 20 cyclin D1-positive MMs were Stage III, in contrast to 19 (49%) of 39 cyclin D1-negative MMs (P = .003). Cyclin D1-positive MMs were more likely to express E2F-1 (16/20 vs. 4/39, P < .001), p53 (11/20 vs. 10/39, P = .041), and p21waf-1 (12/20 vs. 7/39, P = .003). There was no significant difference in mdm-2 expression between these groups. We also assessed proliferation rate using an antibody specific for the Ki-67 antigen. A relatively high percentage (> 20%) of Ki-67-positive cells was found in cyclin D1-positive MMs compared with cyclin D1-negative MMs (13/20 vs. 3/39, P < 0.001). These results suggest that cyclin D1-positive MMs are more likely to possess additional derangements involving other G1 cell-cycle regulatory proteins. We speculate that these abnormalities might result in increased proliferation, thereby explaining the correlation between cyclin D1 expression and greater tumor burden.

Bone Marrow Cells↗
PubMed1998

Frequency of bcl-2 expression in non-Hodgkin's lymphoma: a study of 778 cases with comparison of marginal zone lymphoma and monocytoid B-cell hyperplasia.

The oncoprotein, bcl-2, is expressed in various types of non-Hodgkin's lymphoma (NHL). Immunodetection of this protein is a useful method for distinguishing follicular hyperplasia from follicular lymphoma. Although bcl-2 might also be a useful marker for distinguishing reactive monocytoid B-cell hyperplasia from its putative malignant counterpart, marginal zone lymphoma, there were no extensive studies to date that tested this. Therefore, we performed a survey of bcl-2 expression in 778 cases of NHL using immunohistochemical techniques applied to routinely processed and paraffin-embedded tissues. Of 20 reactive monocytoid B-cell hyperplasias, none were bcl-2 positive, compared with 118 (79%) of 150 marginal zone lymphomas (P = .001). With respect to the follicular lymphomas in our study, of the 110 Grade I lymphomas, 107 (97%) were bcl-2 positive, 119 (83%) of the 143 Grade II lymphomas were positive, and 71 (74%) of the 96 Grade III lymphomas were positive. The bcl-2 positivity of Burkitt-like high-grade B-cell lymphoma was significantly different from that of Burkitt's lymphoma (4 [67%] of 6 vs. 0 of 5; P = .02). T-cell NHL had a significantly lower bcl-2 positivity than did B-cell NHL (10 [45%] of 22 vs. 627 [83%] of 756; P = .0001). Therefore, bcl-2 is a highly sensitive marker for follicular lymphoma and a useful marker for distinguishing reactive monocytoid B-cell hyperplasia from marginal zone lymphoma The significant difference in bcl-2 positivity between Burkitt-like high-grade B-cell lymphoma and Burkitt's lymphoma suggests an additional diagnostic use for this protein.

B-Lymphocytes↗
PubMed1997

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.

Adaptation, Physiological↗
PubMed1997

[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.

Adolescent↗
PubMed1997

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.

Adolescent↗
PubMed1996

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.

B-Lymphocyte Subsets↗
PubMed1996

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.

Adenocarcinoma↗