PubMed Health⌕ Search

Biomedical subjects

L Lombardi

Publications and source records attributed to L Lombardi.

At least 91 records · Page 5Linked to original sources
PubMed1987

Inhibitory activity of a synthetic pentapeptide on leukaemic myelopoiesis both in vitro and in vivo in rats.

The synthetic pentapeptide pGlu-Glu-Asp-Cys-Lys has recently been proposed as the active component of a granulocyte-derived inhibitor of normal haematopoiesis. We investigated its biological activity on leukaemic myelopoiesis both in vitro and in vivo in rats. Three different human permanent myeloid leukaemic cell lines (HL60, KG1, ML3) and a rat transplantable acute myeloid leukaemia (Shay leukaemia) were studied. Neither HL60 nor KG1 were sensitive to the peptide whereas a consistently reproducible inhibition of 3H-TdR uptake was observed in ML3 cells. This effect was not due to a unspecific toxic action on target cells and was spontaneously reversible. When injected i.p. twice daily at an appropriate concentration in rats bearing Shay leukaemia, the peptide caused a significant increase in survival. Our results therefore indicate that the synthetic pentapeptide studied inhibits not only normal but also leukaemic myelopoiesis.

Animals↗
PubMed1987

Plasma cyclic nucleotide levels in acute leukemia patients.

To verify the clinical usefulness of extracellular cyclic nucleotide determination as a tumor marker, plasma cyclic AMP (cAMP) and cyclic GMP (cGMP) levels were measured in 70 normal subjects and 173 acute leukemia patients studied in different stages of their disease. Mean plasma cAMP levels were similar in leukemic and normal subjects, although in 48 patients in the active stage of the disease, first diagnosis, or relapse, the cAMP values were below the normal range, and most of these patients failed to respond to chemotherapy. Plasma cGMP levels were markedly elevated in untreated patients, normalized in all patients who attained complete remission, and increased promptly to pretreatment values in patients who relapsed, suggesting that their determination may be useful to monitor the patients' response to treatment.

Acute Disease↗
PubMed1986

A light microscopic and ultrastructural study of two cases of fibrolamellar hepatocellular carcinoma.

We describe two cases of fibrolamellar hepatocellular carcinoma of the liver in two young women. Both patients presented with diffuse intra-abdominal metastases; nevertheless they had a survival of 28 and 32 months, respectively, which sustains the better prognosis of this neoplasm. Electron microscopy of one case confirmed the oncocytic features of the neoplastic cells and showed intra- and intercellular duct-like vacuoles with numerous microvilli containing a microfilament core that terminated in a terminal web, which represents an unusual aspect in the spectrum of differentiation of fibrolamellar hepatocellular carcinoma.

Adolescent↗
PubMed1986

Inhibition of proliferation of human leukaemic cell populations by deferoxamine.

Deferoxamine is a hydroxylamine which binds ferric ions to form a highly stable complex. Since iron is thought to be required at a critical stage for cell proliferation, we investigated the effect of deferoxamine on the proliferative activity of human leukaemic cell populations in vitro by means of 3 permanent cell lines, HL60, U937 and 8402. We found deferoxamine to be a potent inhibitor of DNA synthesis and proliferation of leukaemic cells, acting by accumulating treated cells at the early S phase of the cell cycle. Suppression of leukaemic proliferation was obtained at deferoxamine concentrations in the range usually achieved in the treatment of patients for iron overload. Deferoxamine might therefore warrant further investigation as a potentially useful agent for leukaemia chemotherapy.

Cell Division↗
PubMed1986

The new AN69 membrane in biofiltration (BF): 18 month's follow-up.

BF is a dialytic procedure employing the new AN69 polyacrylonitrile membrane, which is more permeable to both water and solutes than the traditional AN69. A postdilutional bicarbonate infusion is necessary in BF. The treatment time is 3 hours. Six patients, previously on regular acetate (HD) or bicarbonate dialysis (BHD) with AN69 were treated for 18 months with BF. Biochemical and hematological parameters (BUN, creatinine, uric acid, CA, P, K, Na, blood pH, HCO3, hematocrit) and clinical signs were evaluated in BF, and compared to those of HD and BHD. An improvement in biochemical and hematological parameters accompanied by better clinical signs was seen in BF as compared to HD and BHD. In our opinion this is due both to better removal of small and middle molecules and the bicarbonate infusion, and to the shorter dialytic session.

Acidosis↗
PubMed1985

Adenosine deaminase and terminal deoxynucleotidyl transferase in human lymphomas: an aid to the diagnosis and subclassification of lymphoblastic lymphomas.

Adenosine deaminase (ADA) and terminal deoxynucleotidyl transferase (TdT) activities were determined on 97 biopsy specimens obtained from patients with non-neoplastic diseases (12 cases), Hodgkin (30 cases), and non-Hodgkin lymphomas (55 cases). Thirty additional cases were tested only for TdT. TdT was positive in 10 out of 13 lymphoblastic lymphomas (LL) examined and negative in all the other specimens, including the ten cases of the immunoblastic type. Levels of ADA above 350 U/mg of protein were found in 10 out of 12 LL tested, but not in any other specimen. The 3 TdT- LL had high contents of ADA. Therefore, all LL can be detected using both ADA and TdT markers. The 3 TdT- LL had a heterogeneous phenotype and their possible origin is discussed in view of the possibility that they constitute a rare entity distinct from the more common TdT+ LL. Very low levels of ADA (below 100 U/mg of protein) were found in chronic lymphocytic leukemia and immunocytoma, and in Burkitt's lymphoma. In other B-cell non-Hodgkin lymphomas, intermediate values between 100 and 350 U were often found, and this finding could be relevant to the different cellular origin of the various B-cell neoplasias. We conclude that ADA distribution is solid lymphoid tumors reflects the cellular origin of these neoplasias. Adenosine deaminase alone and in combination with TdT can be useful in the diagnosis and classification of childhood lymphomas in which the immature hystotypes predominate.

Adenosine Deaminase↗
PubMed1985

Angiosarcomas arising in edematous extremities: immunostaining for factor VIII-related antigen and ultrastructural features.

Immunostaining for Factor VIII-related antigen was seen in deparaffinized sections from 19 of 20 postmastectomy angiosarcomas and from four of four sarcomas that arose in chronically edematous tissue unrelated to breast carcinoma. Staining was also seen in sections from two malignant hemangioendotheliomas, four capillary hemangiomas, and one granulation tissue specimen. Sections from two lymphangiomas were immunonegative for Factor VIII-related antigen in the endothelium of lymphatic channels, whereas staining was observed in the surrounding normal blood vessels. Electron microscopic study of four postmastectomy angiosarcomas disclosed ultrastructural features (fenestrae, intense pinocytotic activity, cell junctions, and Weibel-Palade bodies) supporting the blood vascular endothelial nature of the neoplastic cells. It is concluded that a neoplastic blood vessel component is present in sarcomas that arise in chronically edematous tissues. It is questionable whether a lymphatic component is also present. These tumors, therefore, should be regarded as angiosarcomas rather than lymphangiosarcomas.

Adult↗
PubMed1985

Speed of processing in normal aging: effects of speech rate, linguistic structure, and processing time.

Young and elderly adults heard three types of speech materials varying in both length and degree of semantic and syntactic constraints. Time compression was used to vary speech rates systematically to test a speed of processing hypothesis as one explanation of performance deficits associated with normal aging. In addition to segment length effects, the elderly participants showed significantly steeper rates of performance decline with increasing speech rate, with slope constants dependent on the structural constraints of the speech materials. The results are discussed in terms of processing rate hypotheses and context utilization.

Adolescent↗
PubMed1985

Plasma cyclic nucleotide levels in patients with homozygous beta-thalassaemia.

To investigate the possibility that a proliferative non-neoplastic process influences extracellular cyclic nucleotide concentrations, we measured plasma cyclic AMP and cyclic GMP levels in 38 patients with homozygous beta-thalassaemia. This group consisted of 20 patients with thalassaemia major transfused regularly (mean pre transfusion Hb levels, 11 g/dl), and 18 patients with thalassaemia intermedia who did not require regular blood transfusion (mean Hb levels, 8.7 g/dl). In the patient group, plasma cyclic AMP levels were similar to those of 37 normal subjects matched for age and sex, whereas plasma cyclic GMP levels were markedly higher. Moreover, in the thalassaemic patients there was a significant negative correlation between plasma cyclic GMP levels and haemoglobin concentrations, suggesting that their marked erythroid hyperplasia may play a role in determining alterations in extracellular cyclic GMP levels.

Adolescent↗
PubMed1985

Plasma cyclic nucleotide levels in monitoring acute leukemia patients.

To verify the clinical usefulness of plasma cyclic nucleotide determination as a tumor marker, levels were measured in 52 normal subjects and in 106 acute leukemia patients. In untreated patients plasma cyclic GMP (cGMP) levels were markedly elevated, whereas cyclic AMP levels did not significantly differ from those of normal subjects. Plasma cGMP levels normalized in all patients who attained complete remission and remained in the normal range during all the remission period. In the patients who relapsed, an early increase in cGMP levels to the pretreatment values was observed, thus suggesting that their determination may be of clinical relevance in monitoring the patients' response to treatment.

Acute Disease↗
PubMed1984

Plasma and urine cyclic nucleotide levels in patients with neoplastic diseases.

Plasma and/or urine cyclic adenosine 3',5'-monophosphate (cAMP) and cyclic guanosine 3',5'-monophosphate (cGMP) levels were measured in 67 normal subjects, 55 patients with nonneoplastic diseases, and 324 patients with ten different types of cancer. There were no significant differences in plasma and urine cyclic nucleotide levels between normal subjects and patients with non-neoplastic diseases. In untreated cancer patients, plasma and urine cAMP levels were similar to those of normal subjects, whereas plasma and urine cGMP levels were markedly higher. This pattern was common to all the cancer groups studied. Chemotherapy per se did not seem to influence cyclic nucleotide levels in cancer patients. However, plasma and urine cGMP levels normalized in all patients who attained complete remission. Moreover, in acute leukemia patients who relapsed, plasma cGMP levels increased significantly with respect to the complete remission values, thus suggesting that this parameter may be useful in monitoring the response of cancer patients to treatment.

Adolescent↗
PubMed1984

Multienzymatic analyses of human malignant lymphomas. Correlation of enzymatic data with pathologic and ultrastructural findings in Burkitt's and lymphoblastic lymphomas.

Enzyme activity measurements are of great relevance to the classification and biochemical characterization of the various types of leukemias, but they have been much less studied in solid lymphoid tumors. The authors report investigations in human lymphomas. The levels of the following enzymes were determined: terminal deoxynucleotidyl transferase (TdT), deoxyribonucleic acid polymerase alpha (DP alpha), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), thymidine and uridine kinases (TK and UK, respectively), and thymidine phosphorylase (ThPh). Moreover, cytochemical investigations were done in the group of Burkitt's lymphoma (BL) and lymphoblastic lymphoma (LL), and ultrastructural studies were performed in seven of the nine LL of this series. These results were obtained: (1) TdT (90 cases) was highly specific for LL; eight of nine LL were positive, and all other histologic types were negative; the only TdT-, acid esterase (AcE) positive, nonconvoluted LL was probably related to TdT- normal medullary thymocytes, and had an unfavorable clinical course with resistance to a vincristine-and-prednisone-including treatment; (2) ADA (61 cases) could distinguish clearly between the high levels of LL and the low levels found in any other group of lymphomas; among LL, the highest values were found in T-cell-derived neoplasias, and the lowest value in a periodic acid-Schiff (PAS) positive, acid phosphatase negative case that showed the presence of large nucleoli at the ultrastructural analysis, a finding that is unusual for LL and possibly related to a more immature differentiation stage; (3) PNP (39 cases) values alone were not clinically relevant, but together with ADA levels, a subset of T-LL with high ADA:PNP ratio could be selected among LL; (4) DP alpha (61 cases), and TK and UK (37 cases) were found in concentrations reflecting the malignancy of the non-Hodgkin's lymphoma, and were more elevated in the high-grade malignant lymphomas; (5) ThPh (34 cases) was always elevated in Hodgkin's disease, but low in Burkitt's lymphoma and LL; thus, they had a high TK:ThPh ratio that could be useful in predicting clinical response to thymidine treatment. The authors think that taken together, multiple enzyme determinations could be useful in the characterization of human lymphomas.

Adenosine Deaminase↗
PubMed1984

Prosodic features and the intelligibility of accelerated speech: syntactic versus periodic segmentation.

An experiment is reported in which subjects heard paragraph-length samples of time-compressed speech which were interrupted for intermediate reports either on a simple periodic basis or at points corresponding to sentence and major clause boundaries. The passages were spoken in a normal prosodic pattern, in list intonation, or were electronically processed to produce otherwise normal speech specifically deprived of pitch variation. Decrease in intelligibility scores with increasing speech rate was accompanied by a significant effect of place of interruption for report and of the prosodic pattern in which the passages were heard. Interactions among these variables were interpreted to suggest ways in which prosody ordinarily facilitates the determination of syntactic structure in connected speech.

Humans↗
PubMed1984

Ultrastructural similarities and differences of synovial sarcoma, epithelioid sarcoma, and clear cell sarcoma of the tendons and aponeuroses.

The ultrastructural features of synovial sarcoma, epithelioid sarcoma, and clear cell sarcoma of the tendons and aponeuroses were compared to identify differential markers and similarities. A continuous spectrum of modulation of morphologic features of synovial and epithelioid sarcomas was observed. Biphasic synovial sarcoma with pseudoglandular and stromal components represents one extreme of this spectrum. The gradual disappearance of the pseudoglands and the formation of nests of epithelial-like cells, which are characteristic of epithelioid sarcoma, were observed. The cells of clear cell sarcoma, as well as those of synovial and epithelioid sarcomas, form epithelial-like islands; however, the presence of premelanosomes in the former is a feature of neural crest derivatives.

Humans↗