PubMed Health⌕ Search

Biomedical subjects

P G Cachia

Publications and source records attributed to P G Cachia.

18 recordsLinked to original sources
PubMed2001

Timing of the appearance of multipotential and committed haemopoietic progenitors in peripheral blood after mobilization in patients with lymphoma.

The pattern of emergence of multipotential (CFU-A) and committed (CFU-GM and BFU-E) progenitor cells in peripheral blood has been examined in patients with Hodgkin's disease and non-Hodgkin's lymphoma. Mobilization protocols used chemotherapy with or without granulocyte colony-stimulating factor (n=8 and n=5, respectively). In all patients, the numbers of CFU-A, CFU-GM and BFU-E peaked simultaneously, rather than sequentially, suggesting that marrow regeneration after these mobilization protocols occurred from progenitors at all stages of differentiation. We conclude that peripheral blood stem cell harvest strategies based on peak values for total progenitor numbers will also capture maximum numbers of multipotential progenitors. However, the variable relationship between CFU-A and CFU-GM numbers suggests that overall progenitor cell numbers can give only a broad estimate of the absolute numbers of multipotential progenitors in an individual harvest.

Adult↗
PubMed2000

Direct antiglobulin test negative, non spherocytic autoimmune haemolytic anaemia.

We report a case of direct antiglobulin test (DAT) negative warm autoimmune haemolytic anaemia (AIHA). At initial presentation our patient had compensated haemolysis and was DAT positive for complement only. Severe haemolytic anaemia developed some years later with a negative DAT. Spherocytes were not a feature of the blood film and osmotic fragility studies were negative. Immune mediated haemolysis was confirmed by fluorescent activated cell sorter (FACS) analysis using antihuman IgG immunoglobulin. Response to immunosuppression was transient but a good response was achieved following splenectomy. Repeat FACS analysis post splenectomy demonstrated a marked rise in IgG coated red cells. Techniques used in establishing the diagnosis and possible mechanisms for this presentation are discussed.

Aged↗
PubMed1998

Accuracy and precision of the TAS analyser for near-patient INR testing by non-pathology staff in the community.

AIMS: To assess the accuracy and precision of INR measurement by trained practice and district nursing staff using the Thrombolytic Assessment System (TAS) analyser. METHODS: Seventeen nurses from four practices were trained to measure INR using the TAS analyser on citrated capillary blood samples. Quality control (QC) consisted of: daily internal QC using normal and abnormal commercial plasmas; monthly local external QC scheme using fresh citrated venous blood; and registration of all analysers in the NEQAS (national external quality assessment scheme) main users scheme. RESULTS: Analysis of internal QC results demonstrated satisfactory interanalyser and intra-analyser precision with no evidence of analytical drift in any of the four practice analysers over an eight month period. Local and national external QC results confirmed the interanalyser precision but INR was underestimated by the TAS analysers compared with the CA 1000 using either Diagen rabbit brain thromboplastin or Innovin, and with other NEQAS users. CONCLUSIONS: The TAS analyser has many features to commend it for use by nonpathology staff to determine INR. Local internal and external QC and entry into the NEQAS main users group are possible because the TAS analyses citrated plasma or blood. The TAS analyser underestimates INR when the geometric mean normal prothrombin time (GMNPT) is determined by conventional methods. A local correction factor can be introduced by adjusting the normal PT to give INR results comparable with the local laboratory. This is particularly desirable when INRs are measured using both near-patient and laboratory analytical systems on different occasions.

Anticoagulants↗
PubMed1996

Recurrent septicaemia in a neutropenic patient with typhlitis.

We report a case where life threatening gram negative sepsis developed in a patient with CLL in association with post chemotherapy neutropenia on three occasions. Bacterial typhlitis or neutropenic enterocolitis, which is a well described entity of bowel necrosis seen in immunosuppressed patients, was demonstrated at colonoscopy and was the probable portal of entry of micro-organisms. After spontaneous resolution of the typhlitis, further chemotherapy has been given without recurrent sepsis. Typhlitis should be considered as a cause of recurrent septicaemia in neutropenic patients.

Enterocolitis↗
PubMed1995

Lupus anticoagulant in patients with peripheral vascular disease: a prospective study.

OBJECTIVE: To assess the incidence of lupus anticoagulant (LAC) in patients with peripheral vascular disease. DESIGN: Prospective clinical study. SETTING: University Hospital. MATERIALS: 20 patients with claudication (group 2), 20 patients with critical ischaemia (group 3) and 20 patients prior to elective abdominal aortic aneurysm surgery (group 4) were compared to 20 general surgical controls (group 1). CHIEF OUTCOME MEASURES: Venous blood samples for coagulation assay. MAIN RESULTS: Positive results for LAC by the Dilute Russell's viper venom time (DRVVT) with the platelet neutralisation procedure were present in 26 out of 60 vascular patients compared with none of the 20 general surgical controls. The three vascular groups showed a similar prevalence of LAC and this differed significantly from that in the control group (chi 2 = 10.94, p = 0.0009). Of the 26 positive results only three were associated with an abnormal activated partial thromboplastin time (APTT), which has previously been used as a marker for the presence of LAC activity. Fibrinogen levels were raised in seven of 20 patients in group 2 but were normal in the remaining vascular groups (p = 0.001). The mean factor VII level (124.1 units dl-1) in group 2 was higher than the mean of the remaining vascular patients (109.3 units dl-1, p < 0.05). CONCLUSIONS: The high prevalence of LAC in patients with peripheral vascular disease and the associated increased risk of early graft thrombosis may justify routine testing by DRVVT prior to reconstructive vascular surgery. Treatment of these patients with antiplatelet agents or formal anticoagulation perioperatively should be considered.

Aged↗
PubMed1995

A novel CSF-1 binding factor in a patient in complete remission following cytotoxic therapy for lymphoma.

A novel colony stimulating factor-1 (CSF-1) binding factor present in the serum from a patient in remission from lymphoma is described. Radioimmunoassay (RIA) repeatedly failed to detect circulating levels of CSF-1 in the peripheral blood system of this patient. Molecular analysis showed a normal CSF-1 gene structure by Southern blot analysis and a 46,XX karyotype by cytogenetic analysis. CSF-1 mRNA expression in peripheral blood leucocytes was confirmed using reverse transcriptase polymerase chain reaction analysis. Morphological analysis of bone marrow cells was normal and peripheral blood progenitor cell colony assays showed a pattern of growth within the normal range in response to CSF-1 alone and in combination with other cytokines. Analysis of the patient's plasma and conditioned media prepared from peripheral blood mononuclear and granulocytic cell fractions for their ability to bind 125Iodine-labelled CSF-1 revealed the presence of a plasma CSF-1 binding factor. This binding factor was not present in the patient's urine, because CSF-1 was detected by RIA and production of the binding factor by the patients peripheral blood white cells could not be demonstrated in vitro. To our knowledge, this is the first reported case of a soluble CSF-1 binding factor.

Antineoplastic Agents↗
PubMed1994

Non-dysplastic myelodysplasia?

Patients successfully treated for a malignancy with cytotoxic therapy have an increased risk of developing secondary myelodysplasia (MDS) and acute myeloid leukemia (AML). We report a patient in remission from Hodgkin's disease (HD) who remains hematologically normal 4 years after combination chemotherapy, but who has biological and genetic abnormalities characteristic of myelodysplasia. X-inactivation analysis using a 5' phosphoglycerate kinase (PGK) probe demonstrates polyclonal hematopoiesis, but cytogenetic analysis reveals a clonal population with a minority of metaphases having a 7q-deletion. NRAS mutations are not detectable 1 year after treatment, but are present in two separate clones (at codons 12 and 15) analyzed by single-stranded conformational polymorphism (SSCP), followed by cloning and sequencing 4 years after treatment. The presence of an activated NRAS with the same codon 12 mutation was independently confirmed by the nude mouse tumorigenicity assay. In vitro peripheral blood granulocyte-macrophage colony-forming units (CFU-GM) have changed from normal to undetectable levels while erythroid burst forming units (BFU-E) were significantly reduced on two occasions during the period of observation. These abnormalities are characteristic of MDS. Continued clinical follow-up will determine whether these evolving genetic and biological abnormalities pre-date the onset of clinical and morphological features of MDS.

Adult↗
PubMed1993

Expression of the colony-stimulating factor 1 receptor in B lymphocytes.

The FMS proto-oncogene encodes for the colony-stimulating factor 1 receptor (CSF-1R), whose expression within the haematopoietic system has previously been thought to be restricted to cells of the mononuclear phagocyte lineage. We have studied the expression of the CSF-1R in peripheral blood mononuclear cells by indirect immunofluorescence and flow cytometry. FMS expression was detected on both monocytes and B lymphocytes from all samples analysed, including 14 haematologically normal individuals and 31 patients (23 in remission following cytotoxic therapy for lymphoma, six with B-cell chronic lymphocytic leukaemia and two with chronic myelomonocytic leukaemia). The level of FMS expression on B lymphocytes was lower than the level of expression detected on monocytes isolated from the same sample. FMS mRNA expression in B lymphocytes has been confirmed by a reverse transcription-polymerase chain reaction (RT-PCR)-based technique and Northern blot analysis. Thus, FMS may play a role in the normal function of B lymphocytes and, because of its potential oncogenic activity, may contribute to the pathogenesis of malignancies of this cell type.

B-Lymphocytes↗
PubMed1993

Clonal haemopoiesis following cytotoxic therapy for lymphoma.

Patients successfully treated for lymphoma by conventional cytotoxic therapy are at increased risk of developing treatment-related myelodysplasia and acute myeloid leukaemia. In this study we have investigated a group of haematologically normal females in remission from lymphoma for evidence of clonal haemopoiesis as a possible marker for the development of clonal haemopoietic disorders. Unilateral X-inactivation, and hence clonality, can be determined in females heterozygous for X-linked restriction fragment length polymorphisms by differences in methylation between active and inactive X-chromosomes. We have studied methylation patterns at the DXS255 locus and the phosphoglycerate kinase (PGK) gene in 25 females in remission from lymphoma and compared them to 35 normal females. Unilateral X-inactivation was detected in 4/15 patients in remission from lymphoma versus 2/27 normals at the DXS255 locus and in 4/13 treated lymphoma patients versus 0/11 normals at the PGK locus. Six individuals were analysed by both techniques with complete concordance. Unilateral X-inactivation was more common following cytotoxic therapy for lymphoma (7/25) than in normals (2/35) (p < 0.025) and in the lymphoma cohort was associated with increasing time from the end of therapy (p = 0.03). Patients in remission from lymphoma have an increased incidence of clonal haemopoiesis compared to normal individuals. This may be due to either the clonal expansion of an abnormal genetically damaged stem cell or a variation of normal haemopoiesis. Prospective studies will establish whether this finding is associated with an increased risk of developing treatment-related myelodysplasia and acute myeloid leukaemia.

Base Sequence↗
PubMed1992

Methylation of the DXS255 hypervariable locus 5' CCGG site may be affected by factors other than X-chromosome activation status.

Differences in the methylation status of certain cytosine residues between active and inactive X chromosomes can be used to determine X-inactivation in females heterozygous for X-linked restriction fragment length polymorphisms. We have studied methylation patterns in 105 females heterozygous at the DXS255 locus by Southern blotting of PstI and MspI or HpaII double digests and hybridization with the probe M27B. Unequivocal patterns of unilateral or bilateral X-inactivation were obtained in 15/64 and 49/64 cases, respectively. In the remaining 41 cases the results were unclear due to the absence of HpaII digestion of one or both PstI fragments. In 7 samples an unequivocal digestion pattern was demonstrated on repeat analysis, suggesting that the initial ambiguous pattern was due to incomplete HpaII digestion. In certain individuals, methylation at the 5' CCGG DXS255 locus may be affected by factors other than X-inactivation, making analysis of clonality with the M27B probe impossible. These individuals should be clearly identified in studies of clonality.

Blotting, Southern↗
PubMed1989

Distribution of a set of idiotopes detected by a monoclonal antibody panel in 42 cases of chronic lymphocytic leukaemia: definition of potential targets for immunotherapy.

Using a panel of 14 monoclonal V region reactive antibodies generated against a single IgG1 lambda paraprotein we have identified shared idiotopes in a group of 42 patients with chronic lymphocytic leukaemia (CLL). The specificity of cellular staining by indirect immunoperoxidase was confirmed in the majority of cases by an ELISA assay using secreted idiotypic immunoglobulin. In a few cases weak cellular binding by the panel antibodies could not be confirmed as specific for immunoglobulin. Four monoclonal antibodies specific for lambda chain determinants reacted with 5-29% of lambda expressing CLLs but the significance of this is uncertain as the antibodies may be recognizing one of the commoner V lambda subgroups. Two antibodies, which are only weakly reactive with normal serum immunoglobulin, detected heavy chain associated idiotopes which were expressed by 7% and 14% of CLL cases. One of these antibodies detects an idiotope which was expressed significantly more frequently by CLL associated immunoglobulin than by a panel of paraproteins. Such preferentially expressed idiotopes may be useful in investigating the biology of this disorder as well as providing attractive targets for immunotherapy.

Antibodies, Monoclonal↗
PubMed1989

Quantitation of expression of idiotopes recognized by a panel of monoclonal antibodies in normal serum immunoglobulin: use of a novel 4-stage ELISA assay.

This paper describes the application of a sensitive ELISA assay detecting as little as 10 ng/ml of a specific idiotope. Using this assay we were able to divide monoclonal anti-idiotypic antibodies generated using a single IgG1 lambda paraprotein as the immunogen into three distinct groups. Seven antibodies detected determinants which were expressed only by the immunogen. The remaining seven antibodies all reacted with normal serum immunoglobulin. Four antibodies reacted with "public" idiotopes which were strongly expressed by serum immunoglobulin, and three antibodies reacted with "restricted public" idiotopes which were only weakly expressed by serum immunoglobulin. This last group may be of significant interest as agents for the immunotherapy of B-cell malignancies. The conservation of expression of these idiotopes in many individual sera suggests that they have a physiological role in immune regulation and would therefore be excellent targets for immunotherapy of B-cell tumours while their quantitatively low expression by circulating immunoglobulin is unlikely to interfere with tumour cell specific binding in vivo.

Animals↗
PubMed1988

T-cell lymphoma: morphology, immunophenotype and clinical features.

The histology, immunophenotype and clinical presentation of 43 cases of T-cell lymphoma are described. Cases were classified into nine types; T-lymphocytic lymphoma (three), mycosis fungoides (six), Sézary syndrome (two), T-zone lymphoma (13), angioimmunoblastic lymphadenopathy (AIL)-like T-cell lymphoma (five), pleomorphic medium cell (one), large cell immunoblastic (four), large cell polylobated (five) and lymphoblastic (four). The patients comprised 26 males and 17 females aged between 15 and 86 years. The majority showed disseminated disease at the time of diagnosis (18 stage IV, nine stage III, five stage II, eight stage I and three cases not staged). Thirty-one patients showed lymph node involvement. Cutaneous involvement was a common finding (18 cases, 10 cases excluding mycosis fungoides and Sézary syndrome). Details of therapy and clinical follow-up were obtained in 37 cases. With simple chemotherapy only one complete response (7%, 1/16) was obtained. With aggressive therapy 48% (13/27) of patients showed complete responses. Twenty patients died during the follow-up period. Life table analysis showed a 58% probability of surviving 1 year and 36% probability of surviving 3 years. There was a significant difference in survival probability between low/intermediate-grade (lymphocytic, Sézary syndrome, mycosis fungoides and T-zone lymphoma including AIL-type) lymphomas and high-grade (large cell immunoblastic and polylobated and lymphoblastic) lymphomas (P less than 0.025). However, when survival of T-zone and AIL-like T-cell lymphoma was compared with survival of large cell immunoblastic and polylobated lymphomas no significant difference was detected. Age (less than 50 years) and stage I or II disease were associated with significantly better survival (P less than 0.005 and P less than 0.05).

Adolescent↗
PubMed1988

Characterization of a new non-Hodgkin's lymphoma cell line (NCEB-1) with a chromosomal (11:14) translocation [t(11:14)(q13;q32)].

A new cell line, NCEB-1, was established by Epstein-Barr virus (EBV) transformation of peripheral blood mononuclear cells from a patient with centroblastic-centrocytic diffuse lymphoma expressing IgM lambda. The transformed cells were lymphoblastoid, with many cells showing a plasmacytoid morphology. The NCEB-1 cells had cytoplasmic Ig (CyIg), with loss of the surface Ig (SIg) expression. Cytogenetic analysis of the cell line demonstrated two clones with variations: a hypodiploid clone, with a complex karyotype including a t(11;14)(q13;q32) similar to the original tumor cells, and a near tetraploid clone with the same markers. Southern blot analysis of DNA from the patient's neoplastic cells and NCEB-1 demonstrated identical Ig heavy chain gene rearrangement, confirming the origin of the cell line. The cell line was not tumorigenic when tested in an in vitro assay using immunosuppressed mice. NCEB-1 has been in continuous culture for 9 months and will be valuable for the in vivo study of non-Hodgkin's lymphoma and EBV transformation.

Cell Line↗
PubMed1987

Prostatic infiltration in chronic lymphatic leukaemia.

Forty six men with chronic lymphatic leukaemia (CLL) were studied for up to seven years. Six patients required surgery for prostatic outlet obstruction. Histological examination of the prostatic chippings showed variable degrees of infiltration with small mature lymphocytes in all six patients, suggestive of a leukaemic origin for the cells. Patients with chronic lymphatic leukaemia who undergo prostatectomy may have a higher incidence of leukaemic infiltration than has been previously recognised.

Aged↗