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Biomedical subjects

S O'Brien

Publications and source records attributed to S O'Brien.

At least 325 records · Page 18Linked to original sources
PubMed1991

Guinea-pig alveolar macrophages kill Mycobacterium tuberculosis in vitro, but killing is independent of susceptibility to hydrogen peroxide or triggering of the respiratory burst.

Alveolar macrophages from the lungs of guinea-pigs that had been vaccinated, boosted and then intravenously challenged with Mycobacterium microti or Mycobacterium bovis BCG killed tubercle bacilli phagocytosed in vitro. The killing was modest, about 40% of phagocytosed bacilli were killed in a day, but alveolar macrophages from animals that had been vaccinated and boosted but had not received the intravenous challenge did not kill bacilli. Different strains of tubercle bacilli had different degrees of susceptibility to these activated macrophages but there was no correlation between killing by macrophages and mycobacterial susceptibility to killing by hydrogen peroxide. The different strains of tubercle bacilli triggered peroxide release from these macrophages but there was no correlation with susceptibility to killing by macrophages or with virulence in the guinea-pig. However, phagocytic uptake of these strains by the activated macrophages was inversely correlated with virulence, and uptake by activated macrophages was less than uptake by normal macrophages.

Animals↗
PubMed1991

A comparative study of the electrocardiographic effects of tranylcypromine and amitriptyline when prescribed singly and in combination.

The authors treated 53 in-patients aged between 18 and 65 years who were suffering from major depression with either tranylcypromine, amitriptyline or a combination of tranylcypromine and amitriptyline. Electrocardiograms taken before and after treatment were compared. In clinically effective doses amitriptyline gave rise to a significant increase in heart rate when prescribed alone and in combination with tranylcypromine. Single tranylcypromine treatment had little effect on heart rate and gave rise to no change in cardiac conduction as measured by the electrocardiogram. Amitriptyline when prescribed in combination with tranylcypromine was associated with significant lengthening of the PR interval. None of the patients developed pathological changes in their electrocardiograms under the carefully monitored treatment conditions of the study.

Adolescent↗
PubMed1991

Differential dose-related haematological effects of GM-CSF in pancytopenia: evidence supporting the advantage of low- over high-dose administration in selected patients.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a multifunctional haematopoietin which can promote production of several blood cell lineages, though the predominant target cells are neutrophils, monocytes, and their precursors. Occasional undesirable clinical effects include eosinophilia, an increase in blasts, or thrombocytopenia. Here, we describe four patients who were treated with GM-CSF, at subcutaneous doses significantly lower than are conventional, and experienced an unusual response pattern. Three patients had severe pancytopenia associated with chronic lymphocytic leukaemia (CLL) or myelodysplastic syndrome (MDS) and exhibited an unexpected switch in the responsive lineage on high- versus very low-dose therapy. The two CLL patients developed marked eosinophilia (up to 10.0 x 10(9) cells/l) without an increase in neutrophils on 125-300 micrograms/m2/d of GM-CSF. In contrast, when the dose was lowered to 10 micrograms/m2/d, the neutrophils rose to physiological levels, without significant eosinophilia. The MDS patient showed a rapid rise in peripheral blasts (baseline level = 0; post-therapy level = 5.0 x 10(9)/l), without a change in other cell types, when receiving 60 micrograms/m2/d of GM-CSF. After GM-CSF was held, blasts returned to baseline levels; reinstituting therapy at the very low dose of 6 micrograms/m2/d was followed by an increase in platelet counts from 50 to 185 x 10(9)/l with only a minor increase in blasts. The fourth patient, who suffered from severe aplastic anaemia complicated by recurrent gastrointestinal haemorrhage, was only treated with the low-dose regimen. He showed a predominant platelet effect with counts rising from 9 to 169 x 10(9)/l. Very low-dose GM-CSF therapy was devoid of constitutional side effects. The biological implications of these GM-CSF responses are discussed. Our results indicate that, in some patients, GM-CSF may stimulate different target cells depending on the dose. Therefore, in contrast to the results of administration of many classical drugs, there may not always be a direct relationship between the amount of GM-CSF given and the optimal effect.

Adult↗
PubMed1991

Effects of low doses of recombinant human granulocyte-macrophage colony stimulating factor (GM-CSF) in patients with myelodysplastic syndromes.

There has been no previously published experience with granulocyte-macrophage colony stimulating factor (GM-CSF) doses less than 12 micrograms/m2 daily in patients with myelodysplastic syndromes, and most observations have been made at doses greater than or equal to 120 micrograms/m2 daily. We administered 5 micrograms/m2 daily by subcutaneous injection to 29 such patients increasing the dose in patients who did not show a haematologic response. Doses of 5 or 10 micrograms/m2 ('low-dose GM-CSF') produced an increase in neutrophils in 14/29 patients. Response was significantly (P = 0.03) more frequent in patients who had a higher pre-treatment neutrophil count (e.g. 11/16 in patients with greater than or equal to 0.5 x 10(9)/l). A rise in blasts followed administration of low-dose GM-CSF in five patients, all with either refractory anaemia with excess blasts (RAEB) or refractory anaemia with excess blasts in transformation (RAEBT). Platelets decreased in five patients, four of whom had no change in blasts, reverting to baseline when GM-CSF was discontinued. We and others have previously observed similar rises in blasts or decreases in platelets at doses of 120 micrograms/m2 daily. Low-dose GM-CSF produced no constitutional side effects. Our results suggest that low doses of GM-CSF might be initially employed in neutropenic patients with myelodysplastic syndromes who present with pretreatment neutrophil counts greater than 0.5 x 10(9)/l. Increasing the dose, and hence the risk of extramedullary toxicity, only in patients who do not respond to the low dose. Patients who present with lower pre-treatment neutrophil counts might begin treatment at doses above 10 micrograms/m2, but below the 120 micrograms/m2 commonly employed, which may be necessary in relatively few patients.

Aged↗
PubMed1991

Pediatric feeding disorders.

Feeding problems occur in children who have normal development, who have failure to thrive, and who have developmental disabilities. This article focuses on the latter two groups. The characteristics and developmental concerns include family characteristics, parent-child interactions, cognitive development, and oral-motor development. The evaluation process for children with feeding problems should include an interdisciplinary approach with a medical, nutritional, occupational therapy, and behavioral evaluation. The behavioral treatments include the Premack principle, time-out plus reinforcement, and negative reinforcement. Future research should focus on the parent-child interaction process in both mealtime and nonmealtime situations, along with demonstrating parents' and teachers' ability to implement mealtime treatment protocols.

Behavior Therapy↗
PubMed1991

Fludarabine: a new agent with marked cytoreductive activity in untreated chronic lymphocytic leukemia.

Thirty-three patients with chronic lymphocytic leukemia (CLL) with advanced Rai stage (III-IV) or progressive Rai stage (0-II) disease were treated with fludarabine as a single agent. Eleven patients (33%) obtained a complete remission (CR), 13 (39%) a clinical CR with residual nodules as the only evidence of disease (nodular partial remission [PR]), and two patients (6%) achieved a PR for a total response rate of 79%. Response was rapid, usually occurring after three to six courses of treatment. The major morbidity was infection. Febrile episodes occurred in 13% of the courses (pneumonia 6%, minor infection 4%, and transient fever of undocumented cause 3%). Fludarabine appears to be the most cytoreductive single agent so far studied in CLL.

Adult↗
PubMed1991

Clozapine in the treatment of psychotic mood disorders, schizoaffective disorder, and schizophrenia.

BACKGROUND: Although growing research indicates that the atypical antipsychotic agent clozapine is effective in patients with schizophrenia, little is known about the efficacy of clozapine in patients with schizoaffective disorder or psychotic mood disorders. The purpose of this study was to assess whether or not clozapine is effective in some patients with schizoaffective disorder or psychotic mood disorders. METHOD: By surveying treating clinicians and chart data, we assessed treatment response in 85 consecutive patients, including 39 with schizophrenia, 25 with schizoaffective disorder, and 14 with bipolar disorder with psychotic features, who received clozapine for at least 6 weeks at our center. RESULTS: All patients were either inadequately responsive to or unable to tolerate standard somatic therapies. Compared to patients with schizophrenia, patients with schizoaffective disorder and bipolar disorder with psychotic features displayed significantly higher response rates to clozapine. CONCLUSION: Clozapine may be a useful drug in the treatment of patients with schizoaffective disorder or psychotic mood disorders who are treatment resistant or intolerant of side effects.

Adult↗
PubMed1991

Erythropoietin treatment in patients with myelodysplastic syndrome and anemia.

Hematological disorders are commonly complicated by anemia, and the symptoms of red cell deficiency adversely affect the quality of life. Erythropoietin is a glycoprotein which controls red blood cell production. Recombinant human erythropoietin, 50 U/kg/day, was given subcutaneously to 16 patients with myelodysplastic syndrome and anemia. All but one patient was transfusion dependent. Diverse pretreatment endogenous serum erythropoietin levels were noted and ranged from 17 to 3616 IU/l. Two patients (12.5%) demonstrated an improvement in hemoglobin levels obviating the need for transfusions. Their responses lasted 5+ and 7 months with maintenance erythropoietin treatment. The responders had endogenous serum erythropoietin levels of 44 and 170, respectively. Treatment was generally tolerated without constitutional side-effects. However, three patients developed thrombocytopenia and one developed joint pain and leukocytosis on treatment. Overall, six patients showed changes in non-erythroid cells: two patients had an increase in platelet counts; three patients, a decrease in platelet counts; and one patient, an increase in white blood cell counts. Most of these changes reversed rapidly once erythropoietin was stopped. It is concluded that (a) serum erythropoietin levels are extremely variable in anemia patients with myelodysplastic syndrome, (b) only a minority of patients benefit from treatment with recombinant human erythropoietin, and (c) erythropoietin can affect cells of the myeloid and megakaryocytic lineage in a small proportion of patients.

Aged↗
PubMed1991

Efficacy of fludarabine, a new adenine nucleoside analogue, in patients with prolymphocytic leukemia and the prolymphocytoid variant of chronic lymphocytic leukemia.

PURPOSE: To describe the results of fludarabine therapy in patients with prolymphocytic leukemia (PLL) and the prolymphocytoid variant of chronic lymphocytic leukemia (CLL-Pro). PATIENTS AND METHODS: Seventeen patients with a diagnosis of PLL or CLL-Pro received fludarabine 30 mg/m2 over 30 minutes daily for 5 days every 4 weeks alone (12 patients), or with prednisone (five patients). Previously defined criteria for response were used. Differences in response rates according to various characteristics were evaluated by chi-square test. RESULTS: Three patients (18%) achieved complete remission, and three (18%) had a partial remission, for an overall response rate of 35%. Responses were durable and occurred in all involved organ sites. Lower response rates were observed in patients with anemia, thrombocytopenia, advanced Rai stages, and primary resistance to prior therapy. Toxicities were minimal except for febrile episodes associated with therapy. CONCLUSION: Fludarabine has shown encouraging results in these patients and deserves further investigation in combination with other active agents, and in the setting of front-line therapy.

Aged↗
PubMed1990

Mitoxantrone and high-dose cytosine arabinoside for the treatment of refractory acute lymphocytic leukemia.

Twenty-five adult patients with refractory acute lymphocytic leukemia received salvage therapy with mitoxantrone 5 mg/m2 intravenously over 1 hour daily for 5 days and cytosine arabinoside 3 g/m2 intravenously over 2 hours every 12 hours for six doses. Overall, nine patients (36%) achieved complete remission, eight (32%) died during induction, and eight (32%) had resistant disease. No significant associations were found between pretreatment patient characteristics and remission. Remission durations toxic effects were related to myelosuppression. Febrile episodes requiring hospitalization occurred in 23 patients (92%), including five episodes of fever of unknown origin (20%) and 18 episodes of documented infections (72%). The authors conclude that the combination of mitoxantrone and high-dose cytosine arabinoside has significant activity in adults with refractory acute lymphocytic leukemia. The addition of colony-stimulating growth factors to the intensive chemotherapy, and the use of the combination regimen as part of front-line maintenance intensification therapy may further improve the prognosis in these patients.

Adolescent↗
PubMed1990

Results of the vincristine, doxorubicin, and dexamethasone regimen in adults with standard- and high-risk acute lymphocytic leukemia.

One hundred five untreated adult patients with acute lymphocytic leukemia (ALL) were entered on the vincristine, Adriamycin (doxorubicin; Adria Laboratories, Columbus, OH), and Decadron (dexamethasone; Merck Sharp and Dohme, West Point, PA) (VAD) regimen. Induction therapy with VAD and VAD plus cyclophosphamide (CVAD) was followed by a 2-year rotating maintenance program with multiple antileukemic combinations, and included early intensifications with Adriamycin and high-dose cytarabine (ara-C) and a late intensification with cyclophosphamide, carmustine (BCNU), and etoposide (VP-16) (CBV) followed by autologous bone marrow transplantation (BMT). Duration of therapy was 24 to 30 months. Eight-eight patients (84%) achieved complete remission (CR) with VAD-CVAD, and 94 (90%) ultimately had CR with continuation of the maintenance as planned. Induction mortality was 3%; only half of the patients required prolonged hospitalization of 1 week or longer, or intravenous antibiotics. Maintenance therapy was given to 79 patients, while nine with histocompatibility locus antigen (HLA)-matched related donors underwent allogeneic BMT. The median remission duration was 22 months, and the median survival was 19 months. Factors associated with significantly worse CR rates were older age, the presence of hypoalbuminemia or hyperbilirubinemia, L2 or L3 morphology, and myeloid markers on leukemic cells. Those associated with significantly worse remission durations were the presence of elevated leukocyte or absolute peripheral blast counts, Philadelphia chromosome (Ph)-positive or B-cell ALL, L2 morphology, and more than one course to achieve CR. Patients could be divided into standard-risk ALL (28% of patients) and high-risk ALL (72% of patients) with long-term remission rates of 70% versus less than 30%. The 26 patients who underwent CBV autologous BMT had similar long-term outcome compared with 21 patients who did not (older age, medical contraindications, or socioeconomic problems). The presence or absence of myeloid markers on leukemic cells did not affect long-term prognosis. We conclude that VAD therapy is a well-tolerated effective induction regimen. High-risk ALL patients require alternative maintenance investigational approaches.

Adolescent↗
PubMed1990

Cholesterol education at the worksite.

1. Risk factors for coronary heart disease include age, sex, family history, high cholesterol, blood pressure, smoking, and severe obesity. The last four risk factors can be modified with lifestyle changes. 2. Occupational health nurses who provide primary care to workers can assist employees in detecting and treating their elevated cholesterol. Cholesterol screening at the workplace is an effective means for employees to learn their cholesterol level or monitor their dietary progress in lowering their cholesterol. 3. Employees can modify their eating behaviors by developing the skills to make wise dietary choices. Simple dietary self assessment and self monitoring tools will aid employees in monitoring and evaluating their efforts. 4. To successfully implement a cholesterol education program and counsel employees, occupational health nurses need to increase their knowledge of nutrition, specifically the composition of a diet that will help reduce the risks associated with heart disease.

Decision Making↗
PubMed1989

Recombinant interferon-alpha therapy of Philadelphia chromosome-negative myeloproliferative disorders with thrombocytosis.

PURPOSE: The clinical course of patients with myeloproliferative disorders and excessive thrombocytosis may be complicated by serious hemorrhagic or thrombotic events. We have previously reported that interferon-alpha can control severe refractory thrombocytosis in patients with advanced chronic myelogenous leukemia. Therefore, we treated a group of thrombocythemic patients with Ph-negative myeloproliferative disorders, including polycythemia vera and essential thrombocythemia, with recombinant interferon-alpha (rIFN-alpha 2a). PATIENTS AND METHODS: Eight patients with profound elevations in platelet counts received a median induction dose of 5.4 X 10(6) U/day (range, 5.0 to 10.0 X 10(6) U/day) of rIFN-alpha 2a administered intramuscularly or subcutaneously. RESULTS: We observed a significant decline in platelet counts from a median baseline value of 1,929 X 10(9)/L (range, 960 to 2,960 X 10(9)/L) to a median posttreatment value of 431 X 10(9)/L (range, 71 to 1,150 X 10(9)/L) (p less than 0.01). Concomitantly, white blood cell counts declined from a median baseline value of 20.8 X 10(9)/L (range, 10.5 to 40.8 X 10(9)/L) to a median posttreatment value of 6.1 X 10(9)/L (range, 2.9 to 29.0 X 10(9)/L) (p less than 0.02). Correction of thrombocytosis was rapid, with a median of only eight days from the start of therapy to the achievement of a platelet count less than 1,000 X 10(9)/L. Six of eight patients have shown an ongoing response with a median follow-up period of 11 months (range, one to 30 months). There have been no bleeding or thrombotic events during the study. Side effects of rIFN-alpha 2a therapy consisted of fever and flu-like symptoms, with tachyphylaxis developing after one to two weeks of therapy. CONCLUSION: Our observations suggest that alpha interferon may be a promising therapeutic agent for myeloproliferative disorders characterized by thrombocytosis.

Adult↗
PubMed1989

A glutaminase (gis) gene maps to mouse chromosome 1, rat chromosome 9, and human chromosome 2.

A rat cDNA clone encoding a portion of phosphate-activated glutaminase was used to identify DNA restriction fragment length polymorphisms (RFLPs) in sets of somatic cell hybrids and between wild-derived and inbred strains of mice. Segregation of rat and mouse chromosomes among somatic cell hybrids indicated assignment to rat chromosome 9 and mouse chromosome 1. Analysis of chromosome 1 alleles for several genes in an interspecific cross between Mus spretus and C3H/HeJ-gld/gld mice indicates that glutaminase can be positioned within 5.5 +/- 2.0 cM proximal to Ctla-4. Similarly, human-hamster somatic cell hybrids were examined for RFLPs, and four human EcoRI restriction fragments were found to hybridize with the rat glutaminase probe. Two of these restriction fragments cosegregated and mapped to human chromosome 2 in a region that is syntenic with mouse chromosome 1 and rat chromosome 9.

Animals↗
PubMed1989

Genetic characterization of FLA, the cat major histocompatibility complex.

The major histocompatibility complex (MHC) of the domestic cat (termed FLA) has been refractile to genetic and serological definition largely because of repeated failure to detect cytotoxic antibodies in multiparous cats or to elicit antibody following allogeneic lymphocyte immunization. We have developed a protocol for producing cytotoxic alloantisera in the cat following rejection of multiple surgical skin grafts. Of 59 cats subjected to grafting, 13 produced lymphocytotoxic antisera which had varying specificities among a panel of outbred cat cells. A population cluster analysis of the 13 alloantisera permitted the identification of six clusters of overlapping FLA specificities. Serological analysis of cells from 12 cat kindreds led to the definition of 24 allogeneic haplotypes, which segregate as a single Mendelian complex. Feline FLA antisera were characterized as class I or class II specific by immunoprecipitation of FLA gene products on lymphocyte cell surfaces. Abundant antigenic polymorphisms for both class I and class II MHC determinants were discovered, a result consistent with precedence in other species and the common expectation of the adaptive value of MHC variation. Development of feline MHC typing reagents and the definition of haplotypes for the cat hold promise for experimental analysis of valuable feline models for virus-induced immune deficiencies.

Animals↗
PubMed1989

Association of granulocytosis with poor prognosis in patients with acute myelogenous leukemia and translocation of chromosomes 8 and 21.

Forty-three patients with acute myelogenous leukemia (AML) and a translocation 8;21 were reviewed. The patients' median age was 30 years, and 62% were men. Twenty-three patients (53%) had loss of a sex chromosome and ten (23%) had other chromosomal abnormalities in addition to the 8;21 translocation. Complete remission (CR) with induction chemotherapy was achieved in 40 patients (93%). The median CR duration was 18 months (range, 1 to 137+ months). Median survival time was 17 months (range, 0.5 to 138+ months) with a 3-year survival rate of 31%. Twenty-three patients (53%) relapsed between 1 and 58 months after entering remission with reinduction therapy resulting in 8 CRs (35%). Thirteen characteristics were examined for an effect on survival. The most striking finding was a significant association between elevated absolute granulocyte count and poor survival (P = .002). WBC count greater than 10,000/microL was also associated with shorter survival (P = .05). Patient age, albumin level, and platelet count showed trends for survival association. Although patients with AML and t(8;21) are regarded as a favorable group with respect to survival, we found a subset of patients who do very poorly. Intensive or more investigational approaches in first remission should be considered for these patients.

Adolescent↗