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Biomedical subjects

S Nand

Publications and source records attributed to S Nand.

At least 37 records · Page 2Linked to original sources
PubMed1990

Leukemic transformation in polycythemia vera: analysis of risk factors.

Forty-eight patients with polycythemia vera (PV) were retrospectively studied for incidence of acute leukemia over a 12 year period. Initial clinical features, hemogram, RBC mass, B12 levels, neutrophil alkaline phosphatase (NAP), and therapy given were studied for association with development of acute leukemia. There were 25 males and mean age at diagnosis was 61.4 years. Initial Hg was 18.38 +/- 1.86 g/dl, WBC 16.44 +/- 12.92 (x 1,000/mm3), platelets 632.94 +/- 303.81 (x 1,000/mm3), B12 1,030.93 +/- 445.20 pg/ml, and neutrophil alkaline phosphatase (NAP) score 136.63 +/- 55.14. Twenty-three patients were treated with phlebotomy alone and 25 received additional myelosuppressive therapy as follows--2 received p32 alone, 4 alkylating agents alone, 8 hydroxyurea (HU) alone, and 11 received 2 or more (multiple) of these agents. None of those treated with phlebotomy alone but 6 of 25 (24%) patients given myelosuppressive therapy developed acute leukemia (P = .03) after a mean period of 46.8 months from start of myelosuppressive therapy. Four of the 11 patients (36%) receiving multiple agent therapy developed acute leukemia (P = .019). Initial hemoglobin levels, but not the other clinical parameters, were significantly higher in patients who developed acute leukemia (P = .002), and this difference persisted in various subgroups receiving myelosuppressive therapy. Thus, high initial hemoglobin and use of any myelosuppressive therapy are associated with an increased risk of leukemic transformation in polycythemia vera. This risk becomes substantial with the use of two or more myelosuppressive agents. Since myelosuppressive therapy does not prolong survival, its role in the management of polycythemia vera should be reexamined.

Acute Disease↗
PubMed1990

Hemostasis in malignancy.

Hemostatic abnormalities are present in a majority of patients with metastatic cancer. These abnormalities can be categorized as 1) increased platelet aggregation and activation, 2) abnormal activation of coagulation cascade, 3) release of plasminogen activator, and 4) decreased hepatic synthesis of anticoagulant proteins like Protein C and antithrombin III. The abnormal activation of coagulation cascade is mediated through release of Tissue Factor, Factor X activators, and other miscellaneous procoagulants from the plasma membrane vesicles of tumor cells. Macrophages of a tumor-bearing host also produce increased amounts of Tissue Factor. Production of Factor X activators and macrophage Tissue Factor is decreased by warfarin. The ability of the tumor cells to produce platelet-aggregating activity and plasminogen activator parallels their metastatic potential in animal and experimental systems. These studies also show that antiplatelet agents and antibodies against plasminogen activator can suppress the metastatic process. One or more laboratory abnormalities of hemostasis can be shown in up to 95% of patients with metastatic cancer. These abnormalities, however, are unable to predict subsequent development of thromboembolic or hemorrhagic complications. Clinical complications occur in 9-15% of the patients in the form of thrombotic or hemorrhagic disorders. The therapy of tumor-related coagulopathy should be guided by its clinical expression. Subclinical DIC should not be treated. Coumadin is generally ineffective for therapy of thrombosis in cancer patients. There is no consensus regarding the use of heparin in acute promyelocytic leukemia (APL). The defibrination in APL may be from disseminated intravascular coagulation as well as systemic fibrinolysis, as shown by decreased alpha 2 antiplasmin levels. In such cases, epsilon aminocaproic acid plus heparin therapy may be of benefit.

Antithrombin III↗
PubMed1990

Therapeutic plasmapheresis and protein A immunoadsorption in malignancy: a brief review.

Plasmapheresis is being used with considerable frequency in the management of malignant and non-malignant disorders. More recently, staphylococcal Protein A immunoadsorption has been employed in similar clinical situations. In patients with malignancy, plasmapheresis has been shown to produce alterations in plasma proteins, decrease circulating immune complexes, remove "specific" and "non-specific" blocking factors, change immune reactivity, and affect monocyte function. Partial responses have been reported in a small number of patients with carcinoma of lung, colon, and breast following plasmapheresis. In addition, there are reports of favorable responses in patients with melanoma, head and neck tumors, lymphomas, leukemias, and Kaposi's sarcoma in acquired immune deficiency. All these responses were partial and brief, and the treatment did not alter the course of the disease. Plasmapheresis has been useful in the management of hyperviscosity and occasionally of paraneoplastic syndromes. It may also have a role in the treatment of thrombotic thrombocytopenic purpura associated with mitomycin-C therapy. Protein A immunoadsorption, by which circulating immune complexes are selectively removed, can activate the complement system, increase blastogenic responses, and increase the natural killer cell activity. It has been shown to produce partial responses in breast and colon cancer, as well as Kaposi's sarcoma in acquired immune deficiency. It may have a useful role to play in the management of mitomycin-C-associated thrombotic thrombocytopenic purpura. Both plasmapheresis and Protein A immunoadsorption should be considered investigational interventions at this time. Toxicity of plasmapheresis, though uncommon, can be serious and may rarely be fatal. Toxicity of Protein A immunoadsorption is mild, consisting mainly of influenza-like symptoms and rash.

Combined Modality Therapy↗
PubMed1989

POEMS syndrome associated with polycythemia vera.

POEMS syndrome is a multisystem disorder associated with polyneuropathy, organomegaly, endocrinopathy, a monoclonal protein (M-protein), and skin changes. The authors describe a patient with POEMS syndrome who has polyneuropathy of the upper and lower extremities, splenomegaly, impotence, IgA-lambda monoclonal protein (M-protein), and marked thickening of his skin. In addition, he has polycythemia vera. Although myeloproliferative disorders have been reported to occur in association with multiple myeloma, they have not been described with POEMS syndrome. The possible etiology of this association is discussed. This patient was successfully treated with melphalan and prednisone at the time of his initial diagnosis, but relapsed 10 years later. The relapse was treated with pulse doses of prednisone alone with complete resolution of his polyneuropathy and skin changes. This was accompanied by a fall in his IgA levels and improvement of his polycythemia.

Adult↗
PubMed1988

Hypoplastic myelodysplastic syndrome.

Over a period of 8 years 11 of 64 patients seen at Loyola University Medical Center with the diagnosis of myelodysplastic syndrome (MDS) also exhibited bone marrow hypoplasia (marrow cellularity of 25% or less) at presentation. The other 53 had normocellular or hypercellular marrow. Clinical features, hemograms, chromosome analysis, incidence of progression to acute leukemia or aplastic anemia, and survival in each group were compared. Using the French-American-British (FAB) classification, there were seven patients with refractory anemia (RA), one refractory anemia with ringed sideroblasts (RARS), and three refractory anemia with excess blasts (RAEB) in the hypoplastic MDS group. Those with normocellular or hypercellular marrow included 22 with RA, nine with RARS, 12 with RAEB, three with chronic myelomonocytic leukemia, and four with RAEB in transformation; one had chronic diGuglielmo syndrome and two patients were not classified. Patients with hypoplastic MDS had lower hemoglobin levels (median, 8 g/dl versus 9 g/dl), more severe leucopenia (median 3100/microliter versus 4200/microliter) and thrombocytopenia (median, 28,000/microliter versus 75,000/microliter), and marked macrocytosis (mean corpuscular volume (MCV), 107 mu 3 versus 97 mu 3). Nine patients with hypoplastic MDS had a chromosome analysis of the bone marrow, and all were normal. In those with normocellular or hyperplastic bone marrow, 22 such analyses were done, and seven (23%) were abnormal. One patient (11%) from the hypoplastic group and 11 (23%) from the normocellular or hyperplastic MDS transformed into acute leukemia. None progressed to aplastic anemia. With a mean follow-up time of 33 months in the hypoplastic MDS, eight patients (72%) are alive. In the group with normal or hyperplastic MDS, the mean follow up was 47 months, and 27 patients (50%) have survived. The two groups differ significantly in leukocyte count (P less than 0.0015), platelet count (P less than 0.0001), and MCV (P less than 0.0023). There may be a possible difference between these groups related to abnormal karyotype, but it is not statistically significant (P = 0.06). Therapy with pyridoxine, folic acid, prednisone, anabolic steroids, retinoids, or low-dose cytosine arabinoside was not beneficial in hypoplastic MDS. Hypoplastic MDS appears to be a distinct clinicopathologic entity characterized by marrow hypoplasia, macrocytosis, severe leucopenia and thrombocytopenia, low incidence of progression to acute leukemia, and unresponsiveness to conventional therapy.

Adult↗
PubMed1988

Plasmapheresis in the management of heparin-associated thrombocytopenia with thrombosis.

Heparin-associated thrombocytopenia with thrombosis (HATT) is fatal in 29% and leads to limb amputation in another 21% of patients. Patients with arterial thrombosis do worse than do those with venous thrombosis alone. Heparin-associated thrombocytopenia is mediated through IgG or IgM immunoglobulin fractions and is believed to be an immune phenomenon, with heparin acting as a hapten. In addition, endothelial injury may be responsible for the development of thrombosis. Heparin-induced platelet aggregation persists for weeks to months after its withdrawal in these patients. Acute management of HATT includes surgical thrombectomy, thrombolytic therapy, dextran, ancrod, low-molecular-weight heparin, and antiplatelet agents, but overall results remain unsatisfactory. We report the use of plasmapheresis, along with aspirin and dextran, in a patient with HATT. The patient experienced pain relief in 1 day; the heparin-associated platelet aggregation test became negative in 5 days, and there was functional salvage of the affected limb. We suggest that plasmapheresis may be an effective therapy in the management of HATT.

Amputation, Surgical↗
PubMed1987

Hemostatic abnormalities in untreated cancer: incidence and correlation with thrombotic and hemorrhagic complications.

Over a 2-month period, 40 patients with untreated malignancy were studied for protein-C (PRC), antithrombin-III (AT-III), fibrinopeptide A (FPA), routine hemostatic screens, and presence of liver metastases to determine pretreatment changes of hemostasis and relate them to subsequent development of thrombotic or hemorrhagic complications. These patients were observed for a mean period of 18 months. There were 23 males and 17 females with a median age of 64 years. Nine patients had lung carcinoma, 8 colon carcinoma, 7 lymphoma, 5 breast carcinoma, 5 head and neck carcinoma, 2 acute leukemia, 2 prostate carcinoma, 1 adenocarcinoma of unknown primary, and 1 sarcoma. Eight patients had liver metastases. PRC was measured by ELISA, AT-III by radial immunodiffusion, and FPA by RIA. Four patients had decreased AT-III, 28 had decreased levels of PRC, and 39 had elevated levels of FPA. All patients with liver metastases had low PRC. Albumin levels were lower in patients with low PRC (mean 3.3 g/dL v 4.0 g/dL for others). Eight patients, five with liver metastases, developed thrombotic (4), hemorrhagic (3), or both (1) complications. Statistically significant associations were found between (1) presence of liver metastases and development of thrombotic and hemorrhagic complications (P less than .001), (2) presence of liver metastases and decreased PRC (P = .001), and (3) lower albumin levels and decreased PRC (P = .0001). Our study documents early changes of hemostasis in untreated malignancy. We extend previous observations that decreased PRC levels in malignancy may be due to poor synthetic functions of liver. Presence of liver metastases was the only factor associated with subsequent development of thrombotic and hemorrhagic complications. Biochemical markers of hemostatic abnormalities, even though encountered frequently at the time of presentation, are of little predictive value for development of thrombotic and hemorrhagic complications.

Adult↗
PubMed1986

Neurotoxicity associated with systemic high-dose cytosine arabinoside.

High doses of cytosine arabinoside (ara-C) have been used in the treatment of refractory forms of acute nonlymphoblastic leukemia (ANLL) and ANLL occurring after previous antineoplastic therapy. In addition to the usual toxicities associated with antimetabolites, neurotoxicity, mainly in the form of cerebellar dysfunction, develops in a significant proportion of patients receiving high-dose cytosine arabinoside HDara-C. This study was performed to determine the incidence of cerebellar dysfunction in our patients and to determine any factors that predict its development. In this series of 30 consecutive patients receiving HDara-C, confusion with cerebellar signs and symptoms developed in seven (23%). Factors that appear to predispose patients to the development of neurotoxicity are (1) past history of neurologic dysfunction and (2) preexisting and progressive hepatic dysfunction. No peripheral neuropathy was seen. In contrast to previous reports, we did not find neurotoxicity to be dose related. Prophylactic use of pyridoxine does not prevent neurotoxicity.

Acute Disease↗
PubMed1985

Transient Passovoy defect during a febrile illness.

The Passovoy defect is a recently characterized hemorrhagic diathesis. We describe a patient with a febrile illness, possibly from Epstein-Barr (EB) virus, who acquired this defect transiently. Prothrombin time; assays for factors VIII, IX, XI, XII; and Fletcher (prekallikrein) and Fitzgerald (high molecular weight kininogen) factors were normal. No definite circulating inhibitor could be demonstrated. The transient Passovoy defect could possibly be ascribed to the infectious process or sulfisoxazole, which the patient had received.

Adult↗
PubMed1985

Red cell fragmentation syndrome with the use of subclavian hemodialysis catheters.

The red cell fragmentation syndrome can occur due to abnormalities of the heart or the blood vessels or vascular malformations. We describe three patients who developed symptomatic hemolytic anemia due to red cell fragmentation with the use of single-lumen subclavian hemodialysis catheters. Retrospective analysis of 75 other patients who had undergone dialysis through this catheter disclosed five additional cases. Red cell fragmentation appears to be associated with partial catheter occlusion by thrombus or development of a clot at the catheter tip or both. The fragmentation resolved in all cases on withdrawal of the catheter. All patients with this catheter should be closely monitored for the red cell fragmentation syndrome, and the catheter should be withdrawn if it develops. White cell fragmentation was also seen in one patient.

Adult↗
PubMed1976

Fatigue fracture of the femoral neck.

Fatigue fractures in the necks of femurs removed from fresh cadavers were produced experimentally by applying repeated compression and rotational stresses. We found that a load applied once in a physiological direction may be within the ultimate strength of the bone, but may produce a fracture if applied repeatedly. With increased age, chances of fatigue failure increased age, chances of fatigue failure increased and loads of even physiological magnitude produced fatigue fractures. This may also happen during life. The subcapital fractures produced in these specimens were similar to those seen in patients in a clinical practice. This has been reported many times in new young military recruits. In individuals undergoing unusually strenuous exercises, the stress concentrations can be unusually high.

Adult↗