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Biomedical subjects

L M Fink

Publications and source records attributed to L M Fink.

At least 19 recordsLinked to original sources
PubMed1992

Thermospray high-performance liquid chromatography/mass spectrometric determination of cyclosporins.

The cyclic undecapeptides cyclosporin (Csp) A, CspD and dihydro CspC (HCspC) were analyzed by high-performance liquid chromatography/thermospray-mass spectrometry (HPLC/TSP-MS) on line with a UV detector. Positive ion partial (1000-1300 u) mass spectra of these compounds could be obtained with 1-2 pmol injected on column. Mass spectra were characterized by signals corresponding to the [M+H] ions as well as fragment ions derived from the loss of 112 (CspA and CspD) or 44, 114 and 114 + 44 (HCspC) mass units from the parent ion. The same qualitative profile was observed for negative-ion acquisition where the ions were formed by proton abstraction. The application of the technique to the characterization of CspA and its major hydroxylated and dealkylated metabolites in human blood samples is presented.

Chromatography, High Pressure Liquid↗
PubMed1991

Antisperm antibody binding to human acrosin: a study of patients with unexplained infertility.

OBJECTIVE: Antisperm antibody binding to acrosin was investigated by Western Blotting. The clinical significance of this binding specificity was assessed in a 2-year clinical follow-up. DESIGN: Consecutive serum samples positive for antisperm antibodies by both enzyme-linked immunosorbent assay and immunobead testing were evaluated for acrosin-binding specificity. SETTING: The patients were followed in an outpatient setting by private infertility specialists. PATIENTS: Sixty-five consecutive infertile referral patients with positive antisperm antibody were evaluated. Clinical follow-up was obtained on 8 of 9 females with evidence of antibody binding to acrosin and 19 of 26 females with no specific binding to acrosin. INTERVENTIONS: Prednisone therapy was given during six courses of intrauterine insemination with husband's sperm. All treatment decisions were made by private physicians independent of the acrosin-binding result. MAIN OUTCOME MEASURES: Pregnancy status was obtained as part of a 2-year follow-up. RESULTS: Acrosin-binding specificity was demonstrated in 10 (15%) of the 65 patients. Two of the 8 women (25%) with antibody binding to acrosin and 6 of the 19 women (32%) with antisperm antibodies but no specific binding to acrosin delivered normal children. CONCLUSIONS: Although antibody-binding specificity to acrosin could be demonstrated, a 2-year clinical follow-up showed no difference in pregnancy rates when compared with women with antisperm antibodies showing no binding specificity to acrosin.

Acrosin↗
PubMed1991

Rapid preparation of plasma for coagulation testing.

Currently recommended minimum centrifugation of whole blood to produce platelet-poor plasma for routine coagulation assays is 1000g relative centrifugal force for 10 minutes. Many clinical laboratories centrifuge blood for routine coagulation assays from 500g to 2000g, with spin times varying from 20 to 5 minutes. Ninety blood samples, routinely submitted to our coagulation laboratory, were prospectively assayed simultaneously for the prothrombin time, activated partial thromboplastin time, and fibrinogen level, comparing centrifugation at 11,000g for 2 minutes with centrifugation at 1000g for 10 minutes. Routine and readily available equipment and supplies were used. Platelet counts were performed on the supernatant plasma in each sample to determine the efficacy of platelet depletion. Excellent correlation of methods was observed for the prothrombin time, activated partial thromboplastin time, and fibrinogen level. Platelet counts on the plasma supernatant showed no significant difference between the two centrifugation methods. We concluded that high-speed centrifugation at 11,000g with a shortened spin time of 2 minutes and with the use of routinely available equipment and supplies can significantly decrease the specimen preparation time for routine coagulation testing.

Blood↗
PubMed1990

Synchronous diffuse well-differentiated lymphocytic lymphoma and gastric adenocarcinoma presenting as splenomegaly and iron deficiency anemia.

Diffuse well-differentiated lymphocytic lymphoma (D-WDLL) and chronic lymphocytic lymphoma (CLL) represent closely related neoplasms which may have indolent courses. Dating back more than one century, reports of associated second primary malignancies continue to intrigue clinicians. A case of synchronous D-WDLL and gastric adenocarcinoma, presenting as splenomegaly and iron deficiency anemia, is presented. The case and literature are reviewed.

Adenocarcinoma↗
PubMed1987

Collagen-binding of von Willebrand's factor antigen in the classification of von Willebrand's disease.

Analysis of the multimeric structure of von Willebrand's factor (vWf) was compared with vWf-binding to collagen in subjects' plasma. The percentage binding of vWf to collagen was determined by both an enzyme-linked immunosorbent assay (ELISA) method and quantitative immunoelectrophoresis. Normal subjects, type I von Willebrand's disease (vWd), and type II vWd were studied. The authors have found by correlating collagen-binding results with multimeric analysis that normal controls exhibit 85.4 +/- 5.1% collagen absorption of their vWf, patients with type I vWd 80.8 +/- 5.3%, whereas patients exhibiting a deficiency of high molecular weight vWf have 32.3 +/- 16.6% collagen absorption of vWf. The results suggest that this functional assay of vWf can be used in the classification of vWd and in the detection of new dysfunctional forms of vWf.

Antigens↗
PubMed1986

Acid and gastrin levels following pyloric-preserving pancreaticoduodenectomy.

Acid and gastrin production after pyloric-preserving pancreaticoduodenectomy was evaluated in six patients. Five patients had low-normal basal and stimulated acid output; the sixth patient was achlorhydric. Fasting gastrin levels were less than 90 to 105 pg/mL (normal range) in five patients, three of whom had stimulated gastrin levels that remained below this range. Two patients had stimulated gastrin levels of 510 pg/mL and 205 pg/mL, respectively, within 15 minutes of eating; however, both levels returned to normal by 120 minutes' time. The sixth patient had mildly elevated fasting (105 pg/mL) and stimulated gastrin levels (160 to 200 pg/mL) throughout the test period. The results suggest that pyloric-preserving pancreaticoduodenectomy does not lead to either gastric hyperacidity or persistent hypergastrinemia.

Achlorhydria↗
PubMed1979

Analysis of transmembrane proteins from eukaryotic cells.

The topography and properties of plasma membrane proteins from mouse L-929 cells are studied by comparing their availability for enzymatic labeling on the external and internal surfaces of the membrane. In order to study the internal surface, phagolysosomes are prepared from cells after they ingest latex particles. The plasma membrane surrounding these seem to have an "inside-out" orientation. The sugars of the membrane glycoproteins in intact phagolysosomes are not available for interaction with lectins or available for periodate-borotritide labeling. A comparison of the lectin-binding proteins labeled by lactoperoxidase-catalyzed iodination on the external cell surface with those labeled on the internal cell surface suggests that a variety of plasma membrane glycoproteins span the lipid bilayer. Using two-dimensional gel electrophoresis it has been shown that selected proteins are labeled at both the internal and external faces of the plasma membrane. Analysis of the 2-D gel electrophoregrams reveals that there are two distinct prominent proteins at 60,000 and 100,000 daltons which are enzymatically iodinated from both sides of the membrane. The partial hydrolysis of the 100,000 dalton protein reveals that different peptides are iodinated when the iodination is performed on intact cells or on the phagolysosomes. These proteins are extensively phosphorylated in cells incubated with inorganic 32P. We conclude that the phagolysosome is probably oriented in an "inside-out" configuration and that this membrane preparation can be used to study the topographic organization of membrane proteins. The use of oriented membranes, selective labeling of proteins, and affinity separation of proteins in combination with gel electrophoresis to define the position and properties of proteins is discussed.

Animals↗
PubMed1979

Asymmetric distribution of plasma membrane proteins in mouse L-929 cells.

The distribution of plasma membrane-associated proteins was studied by using latex-filled phagolysosomes prepared from cultured mouse L-929 cells as a model of "inside-out" membrane. Proteins from 131I/lactoperoxidase-labeled phagolysosomes, phagolysosomes derived from 131I/lactoperoxidase-labeled cells, and phagolysosomes prepared from [35S]methionine metabolically labeled cells were analyzed by high-resolution two-dimensional gel electrophoresis. The gel patterns of iodinated proteins showed specific differences in the availability of membrane proteins to lactoperoxidase labeling between inside-out and right-side-out membranes. However, at least two prominent [35S]methionine-labeled proteins of approximately 60,000 and 100,000 daltons were available for iodination at both sides of the membrane. Partial proteolysis of the 100,000-dalton protein revealed that different peptides were iodinated when the iodination was performed on intact cells or on phagolysosomes, consisent with the idea that this protein spans the plasma membrane.

Animals↗
PubMed1978

In vitro plasminogen activator activity in human brain tumors.

Cell cultures were prepared from nine human brain tumors. Fibrin plate assays showed plasminogen-dependent fibrinolytic activity in lysates and in material released by these neoplastic cells but not in those from normal adult human white matter. Antibodies against human urokinase caused catalytic inhibition of the urokinase and of the plasminogen activator from WI-38 cells, simian virus 40-transformed WI-38 cells, human prostatic cells, and human ovarian carcinoma cells. However, the anti-urokinase immunoglobulin G did not inhibit the plasminogen activator activity of any of the human brain tumor preparations. These studies indicate that the plasminogen activator produced by human brain tumor cells is antigenically different from the plasminogen activator of other human normal and neoplastic cells.

Brain Chemistry↗