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Biomedical subjects

J W Yarbro

Publications and source records attributed to J W Yarbro.

At least 37 records · Page 2Linked to original sources
PubMed1989

Bone marrow biopsy in the initial staging of Hodgkin's disease.

Results of bone marrow biopsy were retrospectively evaluated in 120 previously untreated patients with Hodgkin's disease. The incidence of bone marrow involvement was 13%. All patients with marrow invasion had B symptoms and/or clinically advanced disease. When patients with bone marrow involvement were compared to those without there were significant differences in the incidence of B symptoms, the clinical stage, hemoglobin levels, leukocyte counts, platelet counts, and serum levels of lactate dehydrogenase and alkaline phosphatase. None of 59 patients with clinical stage IA and IIA had evidence of marrow invasion. This study demonstrates that trephine bone marrow biopsy is of value in detecting marrow involvement in specific subgroups of untreated patients with Hodgkin's disease, i.e., those patients with constitutional symptoms and/or clinical stage III or IV. However, bone marrow biopsy adds little to the initial staging of patients with clinical stage IA and IIA. Routine use of this procedure in such patients may be unnecessary.

Adolescent↗
PubMed1989

Computer-assisted instruction in cancer for third-year medical students using the Physician Data Query (PDQ) system.

During the third-year medicine clerkship, students were instructed in online computer Physician Data Query (PDQ) searches. Each student completed computer searches in at least one of five tumor topics. Students assigned to selected tumor topics performed significantly better on test questions in their assigned topic as compared to the scores of students who were not assigned that topic. Although students were encouraged to use the PDQ ad libitum, within three months of completing the clerkship, only 22 students (20%) had conducted additional searches. We conclude that PDQ instruction may enhance students' knowledge about cancer. Student instruction can be effectively completed with minimal computer time. The results from our program evaluation and the limited student use following completion of the clerkship suggest that we should identify another user group, such as senior housestaff, to generate greater interest and more frequent use of the PDQ.

Clinical Clerkship↗
PubMed1989

Myelodysplastic syndrome: prospective evaluation of fifty-one patients using the Dutcher scoring system.

Fifty-one patients with primary myelodysplastic syndrome were prospectively evaluated using a scoring system based on the presentation blood and bone marrow findings. Twenty-four patients (47%) evolved to acute nonlymphocytic leukemia. Stepwise regression model showed that the scoring system was the only significant variable for predicting transformation to acute leukemia (p = 0.0007, sensitivity 70.8%, specificity 77.8%). Seventy-six percent of patients with a score of 14 or greater developed acute leukemia compared to 19% with a score of 13 or less. Median survival of the entire group was 10 months. The most important prognostic factor for predicting survival was the scoring system (p = 0.0001). Survival correlated inversely with the score. This scoring system may be useful in the management of patients with myelodysplasia.

Acute Disease↗
PubMed1989

Acanthocytosis associated with myelodysplasia.

Dysplastic hematopoiesis associated with erythrocyte macrocytosis is a morphologic hallmark of myelodysplasia. We report the cases of six patients with myelodysplasia in which acanthocytosis was the predominant red blood cell (RBC) abnormality. In each case acanthocytes represented 5% to 10% of circulating RBC forms and was the primary reason for referral in two cases. None of the patients had comorbid conditions known to be associated with acanthocyte formation. Myelodysplasia should be considered in the differential diagnosis of acanthocytosis, particularly in the anemic, elderly individual. Acanthocytosis may be a harbinger of an unrecognized, hematologic stem-cell disorder.

Acanthocytes↗
PubMed1989

The new biology of cancer: future clinical applications.

Our recognition that cancer evolves by clonal selection and that the basis for this selection is the growth advantage provided by the inappropriate expression or suppression of genes present in all normal cells allows us to anticipate that the pathways of this evolutionary process may be discovered. If a finite number of such pathways exist with some commonality between various tumors, there is the possibility to anticipate the mechanisms that cell clones might use for both carcinogenesis and tumor progression and to deal with evolving clones before their survival potential becomes overwhelming. As our biochemical understanding increases we may develop the capability to do the following: to identify individuals who have inherited or acquired defective cancer suppressor genes; to identify precursor lesions more exactly; to characterize the degree of progression of a newly diagnosed tumor (has the metastatic phenotype evolved?); to develop antibodies against cell membrane proteins necessary to tumor progression; to produce immune probes that carry cytotoxins or isotopes to specific cell populations; and to take advantage of cell signals to modify tumor growth. The potential for application of the New Biology to cancer medicine seems endless.

Antibodies, Monoclonal↗
PubMed1988

Breast cancer examination experience of medical students and residents.

A survey of fourth-year medical students and residents at three institutions revealed a low experience in examining patients with primary breast cancer. Although the experience was low, there was high confidence in their ability to examine the breast. Changes in learning experiences are necessary.

Breast Neoplasms↗
PubMed1988

Hematologic effects of heavy metal poisoning.

Heavy metal poisoning can cause a variety of hematologic disorders. Exposure to heavy metals is ubiquitous in the industrial environment and must be considered in the differential diagnosis of many types of anemia. The heavy metals most commonly associated with hematologic toxicity are arsenic and its derivative arsine, copper, gold, lead, and zinc. A few distinctive clinical features characterize the hematologic manifestations of many occult heavy metal poisonings. These features have a limited differential diagnosis. A knowledge of these clinical features can assist the astute clinician in making the correct diagnosis.

Anemia↗
PubMed1988

Management of cancer during pregnancy.

Although cancer during pregnancy is infrequent, its management is difficult for patients, their families, and their physicians. When termination of the pregnancy is unacceptable, decisions regarding the use of irradiation and chemotherapy are complicated by the well-known high risks of abortion and fetal malformation. This risk is concentrated in the first trimester and varies with the choice of chemotherapeutic agents or combinations of agents. There is only minimal evidence of increased risk of malformation or abortion in the second or third trimester. Recent progress in cancer therapy has made cure a reasonable goal, and for some malignant neoplasms, cure is still possible even when initial therapy is modified or delayed. When cure is a reasonable goal, curative therapy should not be compromised by modification or delay. When treatment for cure or significant palliation is not possible, however, the goal should shift to protection of the fetus from damage by the injudicious use of teratogenic cancer therapy. This report will review the available data that may assist in these difficult decisions.

Abnormalities, Drug-Induced↗
PubMed1987

Evans' syndrome associated with microcystic adenoma of the pancreas.

A case of autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura (Evans' syndrome), associated with a microcystic adenoma of the pancreas is reported. Early recognition of this rare entity is important, as corticosteroids and splenectomy are usually ineffective, whereas removal of the tumor may be a cure for this condition. Possible mechanisms of the hemolytic anemia and thrombocytopenia are also discussed.

Adenoma↗
PubMed1987

Diagnosis and treatment of malignant pleural effusion.

Pleural effusion is a common and important complication of malignancy which may at times be difficult to diagnose or treat. Its well recognized association with numerous diseases plus the limitations of our usual diagnostic tests may occasionally cause difficulty. In the oncology patient there are a number of common medical problems associated with the development of pleural effusion which frequently coexist with the malignancy. Pleural effusion may be a presenting or late sign of cancer, and when recurrent can be a vexing symptomatic problem. Fortunately, an increasing number of effective diagnostic and therapeutic modalities are available which, when judiciously applied, facilitate our approach.

Amylases↗
PubMed1987

Bleomycin increases superoxide production in the most active alveolar macrophage subpopulation.

Pig alveolar macrophages were separated into three subpopulations by density centrifugation. The most dense subpopulation of macrophages had the greatest rate of superoxide anion production of 4.4 +/- 2.6 nmol/1 x 10(6) cells/min. Bleomycin had its greatest effect on this subpopulation by increasing the rate by nearly 100% in cells stimulated with phorbol myristate acetate or phorbol dibutyrate. Bleomycin increased the maximum rate of superoxide production without changing the apparent Km of 0.012 microgram/ml. Bleomycin did not quantitatively effect phorbol dibutyrate binding to alveolar macrophages. The cells have 9.1 +/- 1.0 x 10(5) sites/cell with a KD of 16 nmol. Results indicate that bleomycin may enhance superoxide production by effecting steps distal to protein kinase C in the superoxide anion production pathway.

Animals↗
PubMed1987

Collecting cancer registry data with a Cancer Patient Questionnaire.

Tumor registries provide a valuable source of treatment, survival, and epidemiologic data but have been faulted for incomplete and insufficient collection of data. An eight page, 38-item Cancer Patient Questionnaire (CPQ) was developed to collect more extensive information for the tumor registry. The CPQ identified significantly more patients with a family history of cancer than had previously been detected by chart review by the tumor registrar. The CPQ agreed with data collected by the tumor registry in 96% of cases for place of birth, 84% of cases for occupational history, 91% of cases for tobacco use, and 88% of cases for number of pregnancies or live births. The Cancer Patient Questionnaire is complete and easy to use and may replace the chart review in the collection of these data.

Data Collection↗
PubMed1987

Functional hyposplenism.

In the past 15 years, it has become increasingly evident that diverse conditions may be linked with hyposplenism and that hyposplenic individuals are susceptible to overwhelming infection, particularly by the encapsulated organisms such as pneumococci, meningococci, and Haemophilus influenzae. Identification of Howell-Jolly bodies in the peripheral blood smear is the most important clue to the diagnosis. Associated diseases include gastrointestinal disorders, hemoglobinopathies, autoimmune disorders, amyloidosis, neoplasms, circulatory disturbances, and other diseases. Hyposplenic patients should be instructed to report immediately to their physician if they suspect any infection. These patients should receive empiric treatment with antibiotics on an emergency basis at the earliest sign or symptom of infection, and they should also receive prophylactic vaccination against pneumococcal microorganisms.

Bacterial Infections↗
PubMed1986

Vascular toxicity associated with antineoplastic agents.

Vascular complications associated with antineoplastic agents are being reported with increasing frequency. Such vascular toxicity is clinically heterogeneous, ranging from asymptomatic arterial lesions to a fatal thrombotic microangiopathic syndrome. Mitomycin is most commonly implicated in the thrombotic microangiopathic syndrome, while bleomycin, either alone or in combination with a vinca alkaloid or cisplatin, appears to be an important cause of Raynaud's phenomenon. Acute arterial ischemic events, ie, myocardial infarction and cerebrovascular accidents, occur most frequently after cisplatin-based combination chemotherapy. Putative mechanisms for such toxicity include drug-induced endovascular damage, perturbation of the clotting system, platelet activation, an abnormality of thromboxane-prostacyclin homeostasis, autonomic dysfunction, vasculitis, and stimulation of fibroblasts. More than one mechanism may be operative in an individual patient. Better documentation of the incidence and types of vascular toxicity and studies to help elucidate the pathogenesis and management of such toxicity are needed.

Antineoplastic Agents↗
PubMed1986

Bleomycin increases superoxide anion generation by pig peripheral alveolar macrophages.

Pulmonary fibrosis is the major toxic effect of bleomycin chemotherapy; however, the molecular mechanisms of the pathological process are unknown. Since alveolar macrophages produce toxic oxygen metabolites and these can damage lung cells, the effect of bleomycin on superoxide anion production was investigated in subpopulations of pig alveolar macrophages. Cells were lavaged from the lung and separated into three subpopulations according to their density. Their capacity to generate superoxide anions increased the more distally they were located. Bleomycin (5.0 milliunits/ml) increased the rate of superoxide production by 75 +/- 24% in dense alveolar macrophages located in the lung periphery. Hydrocortisone (10.0 micrograms/ml) inhibited this superoxide production by 33 +/- 10%. Results from this study suggest that an excess production of superoxide anions by alveolar macrophages may be the underlying cause of bleomycin pulmonary toxicity.

Animals↗