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Biomedical subjects

J McFarland

Publications and source records attributed to J McFarland.

At least 19 recordsLinked to original sources
PubMed1997

One-tube method for complete HPA-1 genotyping by PCR using sequence-specific primers.

Human platelet antigens (HPA) can be targets for antibody responses that cause life-threatening thrombocytopenia following platelet transfusions or pregnancy. As an aid to diagnosis and prevention, serologic and DNA-based methods have been developed to type HPA. Of the DNA-based strategies, those using the polymerase chain reaction (PCR) are very sensitive, but often require processing of amplification products. Sequence-specific primers (SSP) in the PCR eliminate the need for extensive handling of reaction products beyond gel electrophoresis. However, current methods require a separate reaction for each allele being typed. In this report we describe a method to simultaneously and completely genotype both alleles of HPA-1 in a single PCR. In addition, because the absence of an amplification product might also show the failure of a SSP, we introduced a recombinant template that can only be amplified by the SSP, thus ensuring primer performance and the identified genotype.

Alleles↗
PubMed1996

Leucovorin and high-dose fluorouracil in metastatic prostate cancer. A phase II trial of the piedmont Oncology Association.

We performed a Phase II trial of oral leucovorin and high-dose fluorouracil (5FU) in hormone refractory patients with metastatic prostate cancer who had not had prior chemotherapy. 5FU was given as a 24-hour infusion at a dosage of 4 g/m2 and oral leucovorin at a dosage of 50 mg every 6 hours for four doses, starting with the infusion of 5FU. Fifteen patients were treated and three were not evaluable for response. There were no complete (CR) or partial responses (PR) in 12 evaluable patients (95% confidence interval for CR+PR of 0 to 26%). Three patients had stable disease and the remainder progressed. Toxicities were generally mild to moderate, but one patient died of sepsis while neutropenic. This dose and schedule of leucovorin and 5FU is not better than single-agent 5FU in patients with metastatic prostate cancer.

Aged↗
PubMed1994

Vincristine with high-dose etoposide in advanced breast cancer: a phase II trial of the Piedmont Oncology Association.

Vincristine (VCR) and etoposide (VP-16) have been shown to be synergistic in a murine model, and this combination was studied in a phase II trial. Eligibility required measurable disease, a performance status of 0-2, a life expectancy of > or = 2 months, an interval of at least 3 weeks since the receipt of previous radiation therapy or chemotherapy and recovery from related toxicity, no prior treatment with VCR or VP-16, and no more than two prior chemotherapy regimens (only one for treatment of metastatic disease). Treatment consisted of 0.5 mg i.v. (bolus) VCR followed by 200 mg/m2 VP-16 given over 2 h. Both drugs were given daily for 3 consecutive days every 3 weeks (total dose: VCR, 1.5 mg; VP-16, 600 mg/m2). A total of 18 patients with metastatic breast cancer were accured; 14 had adjuvant chemotherapy and 8 had chemotherapy for advanced disease. As judged by International Union Against Cancer (UICC) criteria, one complete response (CR) and three partial responses (PR) were obtained, for a CR + PR rate of 22% (95% confidence interval, 6%-48%). All responders had soft-tissue involvement only. Six patients had stable disease and 8 showed progression. The median time to treatment failure was 3.5 months, and the median survival from study entry was 8.3 months. The major toxicity was myelosuppression, with 9 patients (50%) experiencing a total WBC of < 1,000/mm3. Grade 2-3 neurologic toxicity was noted in 6 patients (33%) and grade 3 nausea and vomiting was noted in 5 (28%). The combination of VCR and VP-16 is active in advanced breast cancer but is not convincingly superior to either of these agents used alone.

Adult↗
PubMed1992

Diagnosis of hepatitis C virus (HCV) infection using an immunodominant chimeric polyprotein to capture circulating antibodies: reevaluation of the role of HCV in liver disease.

Structural and nonstructural regions of the HCV-encoded polyprotein have been expressed in recombinant yeast, bacteria, or insect cells and used to capture and measure reactive antibodies circulating in different individuals. The putative nucleocapsid protein (C) and nonstructural proteins 3-5 (NS3-NS5) were found to contain the most immunodominant epitopes. The NS3, NS4, and C regions were expressed in yeast in the form of a fused, chimeric polyprotein (C25) and a capture assay for reactive antibody was developed. This anti-C25 assay detects all previously identified HCV-seropositive cases and provides a substantially more sensitive diagnostic for both acute and chronic HCV infections than the current anti-C100-3 (NS4) assay. Anti-C25 was detected more frequently than anti-C100-3 in chronic, transfusion-associated non-A, non-B hepatitis patients from the United States (95% vs. 71%) and Japan (98% vs. 82%), in cryptogenic cirrhosis patients from the United States (62% vs. 28%), and in hepatitis B surface antigen-negative cases of hepatocellular carcinoma from Japan (83% vs. 63%). These data indicate that HCV has a greater role in these liver diseases than was previously thought. In volunteer United States blood donors sampled following the introduction of anti-C100-3 screening, the prevalence of anti-C25 and anti-C100-3 was 0.5% and 0.08%, respectively.

Antigens, Viral↗
PubMed1992

Antivinculin antibodies in sera of patients with immune thrombocytopenia and in sera of normal subjects.

We have characterized a 120-Kd antigen that frequently reacts with serum antibodies from patients with immune thrombocytopenia or normal subjects. Immunoblots made after two-dimensional nonreduced/reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or two-dimensional isoelectric focusing/SDS-PAGE demonstrated that this 120-Kd protein has the same molecular weight under nonreduced or reduced conditions, is not a surface protein, and has an isoelectric point (pl) of 6.4 to 6.5. From these data, one likely candidate is the intracellular platelet protein, vinculin. Monoclonal antivinculin antibody reacts with this 120-Kd protein, and purified human platelet vinculin is bound by antibodies that recognize the 120-Kd protein. Therefore, we conclude that this 120-Kd protein is identical to vinculin. Data obtained from a sensitive enzyme-linked immunosorbent assay demonstrate the presence of naturally occurring antivinculin antibodies in many normal sera. However, the incidence of antivinculin antibodies in patient sera (67%; 55 of 82 sera) is significantly (P less than .01) higher than that in normal sera (40%; 32 of 80 sera), and there is a significant difference (P less than .05) between the mean levels of antivinculin antibodies in patient and normal sera. Whereas the levels of these antibodies in patient and normal sera overlap, 2 of 82 sera from patients with thrombocytopenia express unusually high levels of such antibodies. The pathologic significance of these antibodies remains to be determined.

Autoantibodies↗
PubMed1991

Recommendations for the evaluation and treatment of neonatal autoimmune and alloimmune thrombocytopenia. The Working Party on Neonatal Immune Thrombocytopenia of the Neonatal Hemostasis Subcommittee of the Scientific and Standardization Committee of the ISTH.

The following recommendations of the Neonatal Hemostasis Subcommittee of the Scientific and Standardization Committee of the ISTH for the management of neonatal immune thrombocytopenia were prepared by the working party on neonatal immune thrombocytopenia. Evaluation, diagnosis, and treatment of the mother and neonate with alloimmune and autoimmune thrombocytopenia are discussed and current recommendations provided. This document is likely to require frequent future revision(s).

Autoimmune Diseases↗
PubMed1991

Localization of human platelet autoantigens to the cysteine-rich region of glycoprotein IIIa.

The object of this study was to further localize autoantigenic structures on IIb-IIIa and, if possible, to precisely identify the epitopes recognized by human autoantibodies. In this paper, we identify a 50-kD chymotryptic fragment of IIIa that is recognized by a high percentage of human autoantibodies, typified by the prototype IgG autoantibody RA, which binds to IIIa on intact platelets as well as in an immunoblot assay under nonreduced conditions. Using an immunoblot assay, a carboxy-terminal region of this fragment (33 kD) that contains the cysteine-rich domains of IIIa was found to carry the epitope(s) recognized by the prototype autoantibody RA. The amino-terminal amino acid sequence of the reduced 33-kD fragment, the smallest fragment that retains the RA epitope, is XPSQQDEXSP, and that of the reduced 50-kD fragment is IVQVTFD. This indicates that the 33-kD fragment consists of approximately 175 amino acids beginning at residue 479 and extending at least through residues 636-654, while the 50-kD fragment spans the same region but begins at residue 427. It is apparent that the 33-kD fragment is generated from the 50-kD fragment by additional chymotryptic hydrolysis but remains associated because of the multiple disulfide bonds that are characteristic of this cysteine-rich domain. Sera from 48% of patients with chronic ITP and 2 of 8 patients with acute ITP contain antibodies that bind to the 50-kD fragment in an ELISA. Antibodies of the same specificity are also found in one-third of patients with either secondary immune thrombocytopenia or apparent non-immune thrombocytopenia. We conclude that the 50-kD cysteine-rich region of IIIa is a frequent target of autoantibodies in ITP, but that such antibodies may also be present in cases of thrombocytopenia that cannot be linked to an apparent autoimmune process.

Autoantibodies↗
PubMed1988

Comparison of a totally implantable access device for chemotherapy (Port-A-Cath) and long-term percutaneous catheterization (Broviac).

Because of the difficulty in maintaining vascular access in patients receiving aggressive parenteral chemotherapy, a growing number of patients have had implantation of either percutaneous or subcutaneous devices allowing permanent intravenous access. In our study, between July 1980 and July 1985, 110 patients had placement of a Broviac catheter, while 100 patients had placement of a subcutaneous device via a subclavian venous approach. Both groups of patients were identical regarding age, primary malignancy, chemotherapy, and nutritional status. Catheter-related sepsis occurred in 15% and thrombotic occlusion in 22% of those patients with Broviac catheters, compared with 3% and 1%, respectively, in patients having subcutaneous reservoirs. Although the initial cost of the subcutaneous reservoir is greater, overall cost of maintenance of the percutaneous catheter far exceeds that of the reservoir because of the need for daily catheter care and heparin flushing of the Broviac device, which is unnecessary for the subcutaneous port. Our experience favors the use of the subcutaneous reservoir in patients receiving prolonged chemotherapy.

Antineoplastic Agents↗
PubMed1986

Floppy eyelid syndrome and blepharochalasis.

Floppy eyelid syndrome and blepharochalasis may represent a spectrum of one underlying disease. Two patients with floppy eyelid syndrome and one with blepharochalasis shared important clinical similarities. All three patients displayed eyelid laxity associated with papillary conjunctivitis and ocular surface abnormalities. Histopathologic findings were similar in the three cases, characterized by chronic conjunctival inflammation with normal tarsal collagen. In all three patients surgical horizontal eyelid shortening led to improvement in symptoms and findings.

Adult↗
PubMed1986

Quantitative determination of platelet surface alloantigens using a monoclonal probe.

A monoclonal antibody with specificity for the Fc portion of IgG was used to determine the number of IgG alloantibody molecules bound at saturation to alloantigens of the PlA1 and HLA systems on normal human platelets. In preliminary studies, it was found that the number of cell-bound IgG molecules recognized by this probe correlates well with the number measured by electroimmunoassay, an independent measure of alloantibody binding. PlA1-positive platelets could be divided into two groups binding 34,000-43,000 or 19,000-24,000 alloantibody molecules. Family studies and studies with a cytolytic assay showed that the former group is homozygous and the latter heterozygous for PlA1. Because the number of glycoprotein IIIa (GPIIIa) molecules carrying the PlA1 determinant on the surface of normal platelets is thought to be about 40,000, these findings suggest that each GPIIIa molecule carries one PlA1 determinant. The number of class I HLA molecules expressed on normal platelets was considerably smaller than the number of PlA1 determinants, ranging from 4400 to 10,000 (HLA-A2), 870 to 8400 (Bw4), and 1300 to 5800 (Bw6). Preliminary analysis indicates that stronger or weaker expression of Bw4 and of Bw6 correlates with certain "private" HLA-B determinants carried on the HLA-B molecule as found in previous studies using an indirect method to measure alloantigen density. These findings appear to explain why antibodies reactive with platelet-specific antigens such as PlA1 react more strongly with platelets than HLA-specific antibodies in most serologic tests. The weak expression of HLA determinants on platelets of some subjects may account for the less than perfect correlation between in vitro compatibility tests and post-transfusion platelet survivals observed in most studies.

Antibodies, Monoclonal↗
PubMed1982

A comparison of morphine and methadone disposition in the maternal-fetal unit.

The extent of fetal exposure to a drug is a function of placental and fetal clearances of the drug. We have compared the placental and fetal clearances of morphine and methadone under steady-state conditions in the chronic pregnant ewe preparation. Morphine and methadone were infused at constant rates to the mother and fetus, and steady-state maternal and fetal plasma concentrations of the drugs were determined by radioimmunoassay. At steady state after maternal infusion of the drugs, the maternal: fetal free drug concentration ratios were 7.6 +/- 0.6 for morphine and 2.9 +/- 0.6 for methadone. The clearance of morphine from mother to fetus (24.9 +/- 3.0 ml/min) was fifteenfold less than that of methadone (390.3 +/- 92.8 ml/min). Fetal nonplacental clearance of methadone (381 +/- 89.1 ml/min) was higher than that of morphine (125.6 +/- 15.3 ml/min). Fetal clearance accounted for 67.4 +/- 3.9% of total morphine clearance from the fetal compartment, but only 42.8 +/- 4.9% of total methadone clearance. Fetal clearance of methadone increases with age in the early third trimester. The lower extent of fetal exposure to morphine compared to methadone is due primarily to a slower clearance of morphine across the placenta from mother to fetus rather than a more rapid clearance of morphine by the fetus.

Animals↗
PubMed1982

Combination chemotherapy-radiotherapy with and without the methanol-extraction residue of Bacillus Calmette-Guerin (MER) in small cell carcinoma of the lung: a prospective randomized trial of the Piedmont Oncology Association.

The effect of addition of the nonspecific immunostimulant, MER, to combined treatment with chemotherapy and radiotherapy in small cell carcinoma of the lung was evaluated in a prospective randomized trial involving 102 evaluable patients. Chemotherapy consisted of cyclophosphamide, Adriamycin, vincristine, methotrexate, and CCNU; and radiotherapy was administered to the primary lesion, mediastinum, supraclavicular areas, and whole brain. Of 47 patients administered MER 400 mcg intradermally every six weeks, 12 (26%) attained complete remission with a median survival of 22.9 months. Complete remission was observed in 17 (31%) of 55 patients who received no MER with a median survival of 20.0 months (P greater than 0.05). Survival greater than or equal to 2 years has been observed in five patients who received MER and two patients who did not receive MER. The response rate and duration, survival, and toxicity of the two treatment arms were similar with the exception of cutaneous and occasional systemic reaction to MER. MER as used in this study has not influenced the overall results of a combined modality treatment program for patients with small cell carcinoma of the lung.

Adult↗