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Biomedical subjects

J C Byrd

Publications and source records attributed to J C Byrd.

151 records · Page 9Linked to original sources
PubMedDate not supplied

Outpatient consultation: interaction between the general internist and the specialist.

To define the process of outpatient consultation, the authors conducted a prospective study of 716 consecutive outpatient consultations in a university-based primary care internal medicine practice. The overall consultation rate was 11.9 per 100 patient visits, with 78% of the referrals to other physicians and 22% to non-physician specialists. Consultation rates and patterns of referral varied little between physicians with different levels of experience. Eighteen per cent of the consultations resulted in a no-show by the patient to the consultant. Referring physicians received communications from the consultants 80.5% of the time when appointments were kept. By multivariate regression two variables were shown to be most important in determining the internist's overall satisfaction: 1) how well the consultant aided the internist in his ongoing management of the patient's problem, and 2) how well specific questions were addressed by the specialist. Other statistically significant variables were the clarity and promptness of the consultant's reply, the educational value of the consultation, and specific management recommendations made by the consultant. To improve the consultation process no-shows must be minimized, communication from the consultant maximized, and the interaction between the internist and the consultant bolstered.

Ambulatory Care↗
PubMedDate not supplied

Informed consent for patient transfers to a Veterans Affairs medical center.

OBJECTIVE: To evaluate whether informed consent was obtained prior to transfers of patients from a community hospital to a Veterans Affairs medical center. DESIGN: Cross-sectional study. SETTING: A Department of Veterans Affairs medical center. PARTICIPANTS: Eighty-six consecutive interhospital-transferred patients. Nearly all were white men, with a median age of 62.5 years. Fifty percent had three or more active medical problems and 17% had been transferred from intensive care units. MEASUREMENTS AND MAIN RESULTS: The authors defined informed consent as a discussion of benefits, risks, and alternatives to transfer. Following transfer, patients and physicians were interviewed using standardized parallel questionnaires. Physician-patient communication regarding the benefits and risks of transfer was infrequent. Informed consent was reported for none of the transfers by patient interview, compared with 11% of the transfers assessed by physician interview. Risks of transfer were discussed infrequently according to both physicians (17%) and patients (13%). Physicians perceived a risk to the patient in 21% of patient transfers, and in 36% of transfers defined by objective criteria as high-risk. Physicians recalled discussing benefits of transfer more frequently than did patients (80% vs. 42%,t test, p less than 0.001). Physicians also recalled discussing alternatives to transfer more frequently than did patients (61% vs. 18%, t test p less than 0.001). CONCLUSIONS: Verbal informed consent is obtained infrequently prior to interhospital transfer of patients. Risks of transfer are seldom perceived and discussed with patients.

Aged↗
PubMedDate not supplied

Rat brain PCP receptors: alterations in binding parameters following chronic administration of opiate agonists and antagonists.

Phencyclidine (PCP) is a widely abused drug of the arylcyclohexylamine class which is capable of producing symptoms of acute psychosis in man. PCP interacts with a specific CNS receptor, for which a putative endogenous peptide ligand has been identified. We have investigated whether PCP receptor binding parameters are modulated by activity in central opiate pathways. We have found that chronic administration of both an opiate agonist (etonitazene) and an opiate antagonist (naloxone) are able to decrease the affinity of the PCP receptor for TCP, a thienyl derivative of PCP. Furthermore, naloxone, but not etonitazene, resulted in a significant increase in the Bmax of TCP binding to the PCP receptor. These results suggest that neural activity mediated by CNS opioids systems is capable of affecting the binding parameters of the PCP receptor.

Animals↗
PubMedDate not supplied

Carboxyamido-triazole (CAI)--a novel "static" signal transduction inhibitor induces apoptosis in human B-cell chronic lymphocytic leukemia cells.

Signal transduction is a key mechanism by which both proliferative and apoptotic processes of B-cell chronic lymphocytic leukemia (CLL) cells are mediated. Carboxyamido-triazole (CAI) is a cytostatic signal transduction inhibitor currently being tested in phase II clinical trials. Based on this, we investigated the in vitro activity of CAI in mononuclear cell isolates from patients with B-CLL (n=11). Viability, utilizing the MTT assay, was assessed at varying concentrations (0.01-100 microM) of CAI for 4 days. The CAI concentration required for 50% inhibition of cell viability (LC50), determined by the tetrazolium dye (MTT) assay, at 4 days was 53.5 microM (range 29-74.6; 95% CI+/-14.8). Cells from 6 of 11 patients (3 of whom were clinically fludarabine refractory) had a 27 percent (range 11-43) mean decline in viability at 10 microM after a 4 day drug exposure, a concentration readily attainable in humans. To assess if loss of viability was due to apoptosis, we incubated cells from 4 additional CLL patients with media or CAI (10 microM) for 4 days. Annexin-V/propidium iodine labeling subsequently demonstrated CAI significantly (p=0.049) induces apoptosis (40.1%; 95% CI+/-18.1) as compared to media matched control cells (18.3%; 95% CI+/-11.2). These data provide evidence that CAI can induce apoptosis in human CLL cells in vitro at drug concentrations attainable in vivo. These findings justify phase II studies of CAI in patients with B-CLL.

Antineoplastic Agents↗
PubMedDate not supplied

CD20-directed antibody-mediated immunotherapy induces responses and facilitates hematologic recovery in patients with Waldenstrom's macroglobulinemia.

Waldenstrom's macroglobulinemia (WM, lymphoplasmacytic lymphoma) is a B-cell lymphoproliferative disorder in which CD20 is expressed on tumor cells from most patients. Several small studies have suggested a benefit from the anti-CD20 monoclonal antibody rituximab (Rituxan, MabThera) in patients with WM. In this retrospective study, we examined the outcome of 30 previously unreported patients with WM who received treatment with single-agent rituximab (median age 60; range 32-83 years old). The median number of prior treatments for these patients was 1 (range 0-6), and 14 patients (47%) received a nucleoside analogue before rituximab therapy. Patients received a median of 4.0 (1-11.3) infusions of rituximab (375 mg/m2). Three patients received steroids with their infusions for prophylaxis of rituximab-related infusion syndrome. Overall, treatment was well tolerated. Median immunoglobulin M (IgM) levels for all patients declined from 2,403 mg/dL (range 720-7639 mg/dL) to 1,525 mg/dL (range 177-5,063 mg/dL) after rituximab therapy (p = 0.001), with 8 of 30 (27%) and 18 of 30 (60%) patients demonstrating >50% and >25% decline in IgM, respectively. Median bone marrow lymphoplasmacytic (BM LPC) cell involvement declined from 60% (range 5-90%) to 15% (range 0-80%) for 17 patients for whom pre- and post-BM biopsies were performed (p < 0.001). Moreover, 19 of 30 (63%) and 15 of 30 (50%) patients had an increase in their hematocrit (HCT) and platelet (PLT) counts, respectively. Before rituximab therapy, 7 of 30 (23.3%) patients were either transfusion or erythropoietin dependent, whereas only 1/30 (3.3%) patients required transfusions (no erythropoietin) after rituximab. Overall responses after treatment with rituximab were as follows: 8 (27%) and 10 (33%) of the patients achieved a partial (PR) and a minor (MR) response, respectively, and an additional 9 (30%) of patients demonstrated stable disease (SD). No patients attained a complete response. The median time to treatment failure for responding (PR and MR) patients was 8.0 months (mean 8.4: range 3-20+ months), and 5.0 months (mean 6.1; range 3-12+ months) for patients with SD. These studies therefore demonstrate that rituximab is an active agent in WM. Marked increases in HCT and PLT counts were noted for most patients, including patients with WM who had MR or SD. A prospective clinical trial to more completely define the benefit of single-agent rituximab in patients with WM has been initiated by many of our centers.

Adult↗
PubMedDate not supplied

Monoclonal antibodies against partially deglycosylated colon cancer mucin that recognize Tn antigen.

In order to develop reagents that can detect the exposed core carbohydrate antigens of mucins, we have prepared monoclonal antibodies against partially deglycosylated LS174T human colon cancer mucin. The three monoclonal antibodies, 10F4, 15D3a, and 91S8, stained cancers of the colon, pancreas, stomach, breast, prostate, and lung to a greater extent than corresponding normal tissues. There was no staining of normal pancreas or breast, suggesting that these antibodies may be particularly useful for detecting cancers in these two organs. In homogenates of cultured cancer cells, antigen was detectable in three colon cancer cell lines, but not in a variety of other epithelial cancers. The epitope specificity of all three monoclonal antibodies appears to be for Tn antigen, i.e. GalNAc-alpha-Ser/Thr, based on their recognition of alpha-linked GalNAc, but not T antigen, sialyl Tn, or a range of other structures. However, the three anti-Tn antibodies differed in tissue staining specificity and in relative binding to different mucins. These monoclonal antibodies, prepared against deglycosylated colon cancer mucin, appear to be useful reagents for the immunohistochemical detection of epithelial cancers, especially pancreatic cancer and breast cancer.

Antibodies, Monoclonal↗