Comprehensive health care reform and managed competition.
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Comprehensive Health Care↗
Biomedical subjects
M A Goldberg
Publications and source records attributed to M A Goldberg.
Effect of inflammatory cytokines on hypoxia-induced erythropoietin production.
The effects of the inflammatory cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-6, transforming growth factor-beta (TGF-beta), and tumor necrosis factor-alpha (TNF-alpha) on erythropoietin (Epo) production in Hep3B cells were examined. The addition of IL-1 alpha, IL-1 beta, or TNF-alpha resulted in a dose-dependent inhibition of hypoxia-induced Epo production by as much as 89%. IL-1 beta was the most effective cytokine tested, demonstrating half-maximal inhibition at 0.4 U/mL compared with 1.0 and 10.0 U/mL for IL-1 alpha and TNF-alpha, respectively. TGF-beta also inhibited hypoxia-induced Epo production, but only by as much as 56%. In contrast to IL-1 alpha, IL-1 beta, TNF-alpha, and TGF-beta, the addition of IL-6 to hypoxic Hep3B cells resulted in a dose-dependent stimulation of hypoxia-induced Epo production by as much as 81%. However, IL-6 did not stimulate Epo synthesis in the absence of hypoxia, and was thus synergistic with hypoxia in inducing Epo production. Combinations of IL-1 alpha, TNF-alpha, and IL-6 were found to be additive in their effects on hypoxia-induced Epo production. By Northern blot analysis, Epo messenger RNA levels in Hep3B cells grown in 1% O2 were decreased when concurrently exposed to either IL-1 alpha or TNF-alpha. The effects that IL-1 alpha, IL-1 beta, TGF-beta, TNF-alpha, and IL-6 have on hypoxia-induced Epo production may provide new insights into the signal transduction pathway by which hypoxia leads to changes in gene expression. In addition, the effects of these inflammatory cytokines on hypoxia-induced Epo production in vitro suggest that in various inflammatory disorders these cytokines may affect Epo production in vivo and may play a significant role in the pathogenesis of the anemia of chronic disease.
Blotting, Northern↗
Neuropsychological correlates of white-matter lesions in healthy elderly subjects. A threshold effect.
The clinical significance of white-matter lesions (WMLs) detected by computed tomography and magnetic resonance imaging in healthy elderly subjects has been controversial, with some studies reporting associated deficits in cognition and others failing to document cognitive disturbance. In our sample of 100 healthy elderly individuals, almost half (n = 46) had no WMLs, approximately one fourth had minimal (less than or equal to 1 cm2; n = 27) or moderate (greater than 1 cm2 but less than or equal to 10 cm2; n = 21) WML areas, and six subjects had large WML areas (greater than 10 cm2). Substantial disturbances in basic attention and selected frontal lobe skills were detected in the six subjects with the large WML areas. These findings suggest that a "threshold" of WML area must be present before cognitive deficits are observed. Surprisingly, no significant relationships between duration of hypertension or cholesterol levels and WMLs were detected, suggesting that factors other than vascular disturbances are involved in the origin of at least some WMLs.
Aged↗
Wallstent metallic biliary endoprosthesis: MR imaging characteristics.
Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia.
Biliary Tract↗
A quantitative MRI study of vascular dementia.
We studied the MRI and clinical factors associated with dementia following stroke by quantifying ventricle-to-brain ratio (VBR), anatomic region of infarction, and cortical, subcortical, and white matter areas of infarction in 24 stroke patients with dementia and 29 nondemented stroke patients. The factors that most strongly correlated with dementia were total white matter lesion (WML) area, left WML, VBR, right WML, age, left cortical infarction area, left parietal infarction area, and total infarction area. Using discriminant analysis, these factors correctly classified 28 of 29 nondemented patients and 18 of 24 demented patients. Both cortical and white matter total infarction area measurements were strongly associated with dementia in stroke patients, suggesting that these factors strongly influenced the development of dementia following stroke. There was a strong association between dementia and left- but not right-hemisphere infarction area. The only demographic factor that strongly associated with dementia was age.
Aged↗
Hydroxyurea and erythropoietin therapy in sickle cell anemia.
Hydroxyurea has been shown to increase fetal hemoglobin (Hb F) production in patients with sickle cell disease and therefore has the potential to alleviate both the hemolytic and vaso-occlusive manifestations of the disease. Preliminary evidence indicates that recombinant human erythropoietin (rhEpo) may also induce Hb F. Three sickle cell anemia patients were treated with escalating doses of intravenous rhEpo and, subsequently, with daily oral hydroxyurea. After the optimal hydroxyurea dose was attained, rhEpo was added again. Two additional patients were treated with hydroxyurea alone. Treatment with rhEp, either alone or in combination with hydroxyurea, had no significant effect on the percentage of F reticulocytes or F cells. In contrast, hydroxyurea treatment was associated with a 1.5-fold to sevenfold increase in F cells and a 2.3- to 27-fold increase in the percentage of Hb F. In the three patients whose response reached a plateau, hydroxyurea treatment was associated with lessened hemolysis, decreased serum bilirubin and lactate dehydrogenase levels, and prolonged 51chromium-labeled RBC survival. Hydroxyurea treatment also resulted in decreased numbers of irreversibly sickled cells and in decreased sickling at partial oxygen saturation, increased oxygen affinity, increased total RBC cation content, and diminished potassium:chloride co-transport. All five patients treated with hydroxyurea experienced a decrease in severity and frequency of painful sickle crises. This study confirms that hydroxyurea therapy increases Hb F production and provides objective evidence of a significant reduction in hemolytic rate and intracellular polymerization. In contrast, rhEpo, either alone or in combination with hydroxyurea, offered no measurable benefit. Based on these encouraging preliminary data, large-scale, controlled clinical trials are warranted to study the safety and efficacy of hydroxyurea in the treatment of sickle cell disease.
Administration, Oral↗
Microbial changes in the ocular environment with contact lens wear.
A group of 30 subjects, each fit with a single disposable or non-disposable soft contact lens, was further randomized to a daily wear or extended wear schedule to determine the effect of lens wear on the normal conjunctival flora. Cultures of the subjects' inferior cul-de-sacs were taken at baseline before any lens wear and after one week of lens wear. Additionally, each subjects' lens was removed in a sterile manner and cultured at the end of the one week wear period. In all subjects, the fellow eye was used as a control. There were no statistically significant differences with respect to bacterial culture results between experimental and control eyes. Also, there were no significant differences between the pre- and post-lens wear groups. And no significant differences were found when the larger groups were broken down into different wear schedules and lens types and compared. The results of this study suggest that the ocular flora is not markedly changed after one week of contact lens wear. Also raised is the question of whether an altered ocular flora is an etiologic factor in the development of infectious keratitis in contact lens wearers.
Bacteria↗
Hypoxia up-regulates the activity of a novel erythropoietin mRNA binding protein.
The mechanisms which control the production of erythropoietin (Epo) remain enigmatic. Recent data suggest that the half-time of Epo messenger RNA (mRNA) is increased by hypoxia in Hep 3B cells, a human hepatoma line. The post-transcriptional regulation of other rapidly degraded mRNAs is mediated by sequence-specific mRNA binding proteins. In order to determine if Epo mRNA specific binding proteins exist, we probed cytosolic lysates from Hep 3B cells and mouse tissues with radiolabeled Epo RNA. A cytosolic protein that binds specifically to Epo RNA was identified in the Epo-producing, hepatoblastoma Hep 3B cell line by gel mobility shift assay. This protein was identified in both normoxic and hypoxic cells and bound specifically to a 120-base fragment of the 3'-untranslated region (3'-UTR) of Epo mRNA. Binding was completed with unlabeled Epo RNA, but not with granulocyte-macrophage colony-stimulating factor RNA. Ultraviolet light cross-linked Epo RNA-protein complexes migrated as two bands of 70 and 135-140 kD on sodium dodecyl sulfate-polyacrylamide gels. Binding activity was markedly increased in brain and spleen lysates from mice subjected to 24 h of hypoxia. Therefore, the post-transcriptional regulation of Epo expression in response to hypoxia may in part be due to the interaction of Epo RNA with its specific binding protein.
Animals↗
Erythropoietin mRNA levels are governed by both the rate of gene transcription and posttranscriptional events.
The human hepatoma cell line, Hep3B, synthesizes large quantities of erythropoietin (Epo) mRNA and protein in a regulated manner in response to hypoxia and cobaltous chloride (CoCl2). To further understand the regulation of Epo gene expression, we studied the effects of hypoxia and CoCl2 on the rate of Epo gene transcription. While Northern blot analyses showed that steady-state Epo mRNA levels increase more than 50-fold in response to hypoxia or CoCl2, nuclear run-off experiments demonstrated only a 10-fold increase in Epo gene transcription in response to these stimuli. In the presence of either actinomycin D (Act D) or cycloheximide, the stability of biologically functional Epo mRNA was much greater than that observed in the absence of these agents and much greater than that which has been reported in vivo. These findings suggest that the stability of Epo mRNA is modulated by the transcription and translation of rapidly turning over gene product(s). Thus, Epo mRNA levels are determined by both the rate of gene transcription and posttranscriptional events. These experiments demonstrate a potential pitfall in estimating mRNA half-lives based on Act D chase experiments alone.
Blotting, Northern↗
Regulatory elements of the erythropoietin gene.
Because the human hepatoma cell line Hep3B produces erythropoietin (Epo) in a regulated fashion, it can be used to investigate the cis-acting regulatory elements of the Epo gene. Comparison of primate and mouse sequences shows strong homology not only in the coding sequence but also within the 5' flanking region, the first intron, and the 3' flanking region. These portions of the Epo gene were inserted 5' and 3' to a reporter gene, human growth hormone (GH). 5A is a 1,192-base pair (bp) HindIII-Xbal fragment that extends from 378 bp 5' to the cap site through the first intron. To obviate the problem of false initiation of translation from the Epo ATG start codon, this site was changed to TAG by site-directed mutagenesis. 3A is a 255-bp Accl-BglII fragment that extends 67 bp upstream from the Epo termination codon and covers most of the 3' noncoding region of homology. The plasmid DNAs were transfected by electroporation into Hep3B cells with RSVCAT as an internal standard to correct for transfection efficiency. One aliquot of cells was exposed to 50 mumol/L CoCl2 or to 1% O2. At the end of the incubations, GH and Epo were measured in the cell media and the cell pellet was assayed for CAT. Production of GH was stimulated 1.7-fold by cobalt or hypoxia. Furthermore, addition of 3A to the GH gene, irrespective of orientation, stimulated GH production 2.6-fold with CoCl2 and 2.3-fold with hypoxia. Stable cell lines were produced by cotransfection of the above constructions, along with the selectable marker pSV-Neo. In two clones, exposure to hypoxia resulted in much more marked (16-fold) induction of GH. Stimulus of both GH and Epo production by hypoxia was partially abrogated by carbon monoxide. These results demonstrate the presence of promoter and enhancer elements within the human Epo gene that are appropriately responsive to hypoxia and cobalt.
Animals↗
Importance of daily rounds by the radiologist after interventional procedures of the abdomen and chest.
A prospective study was performed to evaluate the clinical utility of daily rounds by the radiologist for patients with indwelling catheters in the chest and abdomen, placed during interventional radiologic procedures. The 7-week evaluation included documentation of the number of patients seen, time spent with each per day, number of problems identified, management of these problems, and consultations for new cases generated by interaction with other staff. During the 268 visits to 37 patients, 59 catheter-related problems were identified; 17 (29%) required further intervention in the radiology department, and 42 (71%) were managed at the patient's bedside. Of the patients who were followed up, 22 (59%) had some catheter-related problem identified during their hospital stay. Daily rounds by the radiologist are an essential component of patient care after catheter-related interventional procedures and should be made by those who perform and understand the procedures.
Catheterization↗
Erythropoietin gene regulation: from the laboratory to the bedside.
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Anemia↗
Differentiation between hemangiomas and metastases of the liver with ultrafast MR imaging: preliminary results with T2 calculations.
We studied the efficacy of T2 measurements at high field strength in distinguishing between liver hemangiomas and hepatic metastases when an ultrafast (single-excitation) MR imaging technique is used. Fourteen patients with known liver tumors were imaged in a 2.0-T prototype ultrafast MR scanner with a spin-echo (infinite TR and TE of 30-340 msec) pulse sequence. Each image was obtained with a total data acquisition time of 20 msec. T2 calculations for hepatic metastases (n = 6) showed a mean of 79.3 +/- 13.5 msec, whereas hemangiomas (n = 8) showed a T2 of 139.8 +/- 18.8 msec (p less than .0001). T2 values of lesions had a smaller relative standard deviation than previously reported, and the range of T2 values of hemangiomas (119-181 msec) and metastases (68-103 msec) did not overlap. Our preliminary results suggest that T2 calculations with ultrafast MR imaging may be useful for differentiating hemangiomas from metastases. We hypothesize that T2 values obtained from ultrafast MR images are more reliable than those obtained from conventional MR images, primarily because of the elimination of T1 information and effects of motion on image signal intensity.
Carcinoid Tumor↗
Erythropoietin therapy in cancer patients.
The majority of patients with cancer become anemic during the course of their disease. This anemia appears to be due largely to a blunted erythropoietin (Epo) response and an impaired ability of the bone marrow to respond to endogenous Epo. Both are exacerbated by chemotherapy and radiation therapy. Recombinant human erythropoietin (rhEpo) ameliorates the anemia associated with malignancy. However, we do not yet know whether rhEpo will decrease the need for homologous blood transfusions and improve the quality of life of cancer patients. While rhEpo will greatly alter the treatment of anemia in the 1990s, its precise role in the treatment of oncology patients is still being elucidated.
Anemia↗
Regulation of the erythropoietin gene in Hep 3B cells.
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Animals↗
Serum erythropoietin levels in patients receiving intensive chemotherapy and radiotherapy.
To investigate the potential role of recombinant human erythropoietin (rhEpo) in patients receiving intensive cytotoxic therapy, we measured the endogenous levels of Epo in 31 patients undergoing bone marrow transplantation (BMT). Seventeen patients underwent allogeneic BMT and 14 underwent autologous BMT. On average, 10 +/- 4 units of red blood cells (RBCs) were transfused per patient. The mean RBC transfusion requirement of the autologous BMT patients was significantly greater than that of the allogeneic recipients (12 +/- 3 v 8 +/- 4, P less than .01), although both groups were maintained at comparable hematocrits. Epo levels were measured by radioimmunoassay (RIA). For each patient, baseline serum Epo levels were determined at time of admission to the hospital. Subsequent samples were collected within 24 hours of completing chemotherapy and/or radiotherapy, and on days 7, 14, and 28, after BMT. Hematocrits (Hcts) were measured daily. All patients had an initial serum creatinine less than or equal to 1.5 mg/dL. Despite considerable differences in absolute Epo levels among individuals, a characteristic pattern was observed. Following admission to the hospital and initiation of cytotoxic therapy, the average Hct decreased and the average Epo level initially increased. The mean serum Epo levels peaked on day 7 post-BMT (284 +/- 190 mU/mL) and fell steadily thereafter. While the average Hcts on day 7 and on day 28 post-BMT were not significantly different (28 +/- 4.6% v 29 +/- 3.3%, respectively), the average serum Epo levels decreased fourfold (P less than .01) during this same period. Moreover, day 28 post-BMT mean Epo levels were inappropriately low (P less than .05) when compared with a reference population with bone marrow failure and normal controls who had not received cytotoxic therapy. We conclude that the endogenous Epo response appears to be blunted during the 3 to 4 weeks immediately post-BMT. Therefore, clinical trials assessing the efficacy of the administration of rhEpo in the treatment of anemias associated with cytotoxic therapy are warranted.
Adult↗
Treatment of sickle cell anemia with hydroxyurea and erythropoietin.
BACKGROUND: Hydroxyurea increases the production of fetal hemoglobin (hemoglobin F) in patients with sickle cell anemia and therefore has the potential for alleviating both the hemolytic and vaso-occlusive manifestations of the disease. There is preliminary evidence that recombinant human erythropoietin may also increase hemoglobin F production. METHODS AND RESULTS: We treated five patients with sickle cell disease with escalating doses of intravenous erythropoietin for eight weeks. Three of these patients were subsequently treated with daily doses of oral hydroxyurea. After the optimal dose was determined, erythropoietin was then given along with hydroxyurea for four weeks. Treatment with erythropoietin, either alone or in combination with hydroxyurea, had no significant effect on the percentage of hemoglobin F-containing reticulocytes (F reticulocytes) or red cells (F cells). In contrast, hydroxyurea treatment was associated with a 3-to-25-fold increase in F reticulocytes, a 1.6-to-7-fold increase in F cells, and a 2.3-to-16-fold increase in the percentage of hemoglobin F. In all three patients given hydroxyurea, treatment with this drug was associated with reduced hemolysis, shown by decreases in serum bilirubin and lactic dehydrogenase and prolongation of red-cell survival. Hydroxyurea treatment also resulted in a decrease in the percentage of irreversibly sickled cells and sickling at partial oxygen saturation, an increase in oxygen affinity and total red-cell cation content, and a reduction in potassium-chloride cotransport. All three patients had a decrease in the number of pain crises. CONCLUSIONS: This study confirms that hydroxyurea therapy increases hemoglobin F production and provides objective evidence that hydroxyurea reduces the rate of hemolysis and intracellular polymerization of hemoglobin S. In contrast, recombinant human erythropoietin, whether alone or in combination with hydroxyurea, offers no measurable benefit.
Administration, Oral↗