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Biomedical subjects

L J Miller

Publications and source records attributed to L J Miller.

At least 217 records · Page 12Linked to original sources
PubMed1986

Large molecular forms of cholecystokinin circulating in humans.

Molecular heterogeneity between cholecystokinin (CCK) present in humans and that present in the pig has been proposed. We recently demonstrated that CCK-8 exists in humans in form identical to the porcine peptide. The aims of this work were to evaluate the presence in human plasma of CCK forms larger than CCK-8 and to compare them with the well-characterized porcine forms. Antiserum (no. 4899) was raised in a New Zealand white rabbit immunized with porcine CCK-33 that had specificity for the 7 to 21 region of that peptide and that recognized molecules present in human plasma. To characterize these, postprandial human plasma was applied to an immunoaffinity column generated with this antiserum. Adsorbed peptides were eluted, concentrated on an octadecylsilane cartridge, separated by reversed-phase HPLC and gel filtration chromatography, and screened by cross-reacting and specific CCK and gastrin radioimmunoassays and CCK bioassay by quantification of amylase release by rat pancreatic acini. Two peptides were consistently identified that possessed CCK-like but not gastrin-specific immunoreactivity and CCK-like biological activity. These appeared to be similar in size to CCK-33 and intermediate in size between CCK-33 and CCK-8. Though analogous to porcine CCK based on antibody cross-reactivity and biological activity, the human peptides were heterogeneous from the porcine peptides based on differing chromatographic behavior.

Amylases↗
PubMed1986

Hepatic processing of cholecystokinin peptides. I. Structural specificity and mechanism of hepatic extraction.

Since the liver is a target tissue of many biologically important molecules, we have studied the hepatic uptake of cholecystokinin (CCK) with the isolated, perfused rat liver and a series of radioiodinated and unlabeled CCK peptides. Of the naturally occurring forms of CCK, cholecystokinin octapeptide (CCK-8) was extensively extracted (26 +/- 0.7% of Bolton-Hunter-labeled CCK-8, 59% of unlabeled CCK-8) in a single pass through the liver, while CCK-33 was minimally extracted (3.1 +/- 1.2% of Bolton-Hunter-labeled CCK-33). Studies of structural specificity showed that the sulfate ester on the tyrosine residue of CCK-8 decreased its hepatic extraction, that the carboxyl-terminal tetrapeptide region of CCK-8 was more important for this uptake process than was the amino-terminal tetrapeptide region, and that oxidation reduced uptake of CCK. First-pass hepatic extraction of unlabeled CCK-8 was shown to be a high-capacity process; however, uptake of radioiodinated CCK-8 was partially saturable with unlabeled CCK-4. Specific lectins (wheat-germ agglutinin, concanavalin A) and a bile acid (taurocholate) inhibited hepatic extraction of CCK-8 in a concentration-dependent manner. These data are consistent with a highly specific cellular extraction process for CCK in the liver.

Animals↗
PubMed1986

Hepatic processing of cholecystokinin peptides. II. Cellular metabolism, transport, and biliary excretion.

We have shown that radiolabeled cholecystokinin octapeptide (CCK-8), CCK-8-desulfate, and CCK-4 are extracted by the liver in a structurally specific manner. Thus, we studied the fate of the extracted radiolabeled peptides by quantitating biliary excretion and determining the nature of the metabolites in bile. There was rapid biliary excretion of labeled CCK-8, CCK-8-desulfate, and CCK-4 by the isolated, perfused rat liver; greater than 75% of the extracted dose and greater than 20% of the injected dose appeared in bile within 20 min after a single pass across the liver. By means of high-performance liquid chromatography and immunoprecipitation, we showed that CCK-8-desulfate and CCK-4 appeared in bile in completely metabolized forms. In contrast, for CCK-8, approximately 20% of the major forms of the label in bile was intact labeled octapeptide. To gain insight into the subcellular sites of metabolism and transhepatic transport of CCK-8, we also determined the effects of taurocholate, lysosomotropic agents, and microtubule binding agents on biliary excretion. Taurocholate had no effect on the percentage of the extracted label excreted into bile. Neither the percentage of the extracted label excreted into bile. Neither lysosmotropic agent, leupeptin, nor chloroquine affected the percentage of the extracted label or the nature of the metabolites appearing in bile. Two microtubule binding agents, vinblastine and colchicine, also did not affect the percentage of the extracted label appearing in bile.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Management of the Zollinger-Ellison syndrome in patients with multiple endocrine neoplasia type I.

Treatment of the Zollinger-Ellison syndrome (ZES) in patients with multiple endocrine neoplasia type I (MEN I) is controversial. Unlike other patients with ZES who have a single tumor and in whom curative surgical resection is possible and desirable, patients with ZES and MEN I tend to have multiple pancreatic islet cell tumors. Therefore the chances for surgical cure are usually different. A retrospective review of 25 patients with ZES as a manifestation of MEN I seen at our institution between 1960 and 1984, an interval during which histamine type 2 (H2) receptor antagonists were introduced, provided an opportunity to study this problem. Follow-up averaged 6 1/2 years. All patients diagnosed before 1979 (14 patients) underwent surgical exploration. Ten patients (71%) had pancreatic procedures (five enucleation, four partial pancreatectomy, and one enucleation of multiple nodules with subsequent total pancreatectomy). None of these procedures was curative, and all patients required further medical and/or surgical therapy for peptic ulceration. Eighteen patients (72%) underwent gastric surgery. Seven patients had subtotal gastrectomy, five of whom required subsequent total gastrectomy. Thirteen patients ultimately had total gastrectomy. There were no immediate postoperative deaths. All patients with diagnoses since 1979 (11 patients) had H2-antagonist therapy as primary treatment. No significant complications were associated with this approach during a mean treatment period of 26 months. Only one of these patients subsequently has required gastric surgery. The proved efficacy of H2 antagonists, coupled with the recognition of the diffuse nature of the pancreatic disease in these patients, has led to a change in the therapeutic approach over the period reviewed. H2-antagonist therapy should be the initial treatment of choice in patients with MEN I who have ZES.

Adult↗
PubMed1986

p150,95, the third member of the Mac-1, LFA-1 human leukocyte adhesion glycoprotein family.

Monoclonal antibodies specific for p150,95, a third member of the Mac-1 and lymphocyte function-associated antigen-1 (LFA-1) leukocyte adhesion protein family, have been identified and used to study the biochemistry and cellular expression of p150,95. p150,95 is a noncovalently associated heterodimer containing alpha X and beta subunits of Mr = 150,000 and 95,000 respectively. Findings suggest that the p150,95 alpha X beta complex shares a common beta subunit with the alpha L beta LFA-1 and alpha M beta Mac-1 complexes. Co-precipitation experiments demonstrated identity between the p150,95 molecule precipitated by anti-beta MAb and by p150,95-specific MAb. Patients with a previously demonstrated genetic deficiency in Mac-1 and LFA-1 fail to express p150,95. Deficiency of the Mac-1, LFA-1, and p150,95 alpha beta complexes on the surface of patient cells appears due to a defect in the common beta subunit. The lack of cross-reaction of p150,95-specific MAb with LFA-1 and Mac-1, which appear to utilize identical beta subunits, suggests that the determinant is specified by the alpha X rather than the beta subunit of p150,95. The data suggest that alpha X is yet a third member of a family of alpha subunit proteins that associate with a common beta subunit, are differentially regulated in leukocyte differentiation, and function in adhesion reactions. p150,95 is normally expressed on blood monocytes and granulocytes. Chemoattractants such as f-Met-Leu-Phe stimulate a rapid, fivefold increase in surface expression that is not dependent on protein synthesis and appears to reflect mobilization of an intracellular latent pool. The intimate relation between the lack of chemoattractant-stimulated upregulation of p150,95 and Mac-1 by patient granulocytes and their failure to upregulate adhesiveness to these same stimuli in vitro, or to diapedese and migrate into inflammatory sites in vivo, is discussed.

Antibodies, Monoclonal↗
PubMed1985

The severe and moderate phenotypes of heritable Mac-1, LFA-1 deficiency: their quantitative definition and relation to leukocyte dysfunction and clinical features.

An inherited syndrome characterized by recurrent or progressive necrotic soft-tissue infections, diminished pus formation, impaired wound healing, granulocytosis, and/or delayed umbilical cord severance was recognized in four male and four female patients. As shown with subunit-specific monoclonal antibodies in immunofluorescence flow cytometry and 125I immunoprecipitation techniques, in addition to a NaB3H4-galactose oxidase labeling assay, granulocytes, monocytes, or lymphocytes from these individuals had a "moderate" or "severe" deficiency of Mac-1, LFA-1, or p150,95 (or a combination)--three structurally related "adhesive" surface glycoproteins. Two distinct phenotypes were defined on the basis of the quantity of antigen expressed. Three patients with severe deficiency and four patients with moderate deficiency expressed less than 0.3% and 2.5%-31% of normal amounts of these molecules on granulocyte surfaces, respectively. The severity of clinical infectious complications among these patients was directly related to the degree of glycoprotein deficiency. More profound abnormalities of tissue leukocyte mobilization, granulocyte-directed migration, hyperadherence, phagocytosis of iC3b-opsonized particles, and complement- or antibody-dependent cytotoxicity were found in individuals with severe, as compared with moderate, deficiency. It is proposed that in vivo abnormalities of leukocyte mobilization reflect the critical roles of Mac-1 glycoproteins in adhesive events required for endothelial margination and tissue exudation. The recognition of phenotypic variation among patients with Mac-1, LFA-1 deficiency may be important with respect to therapeutic strategies.

Adolescent↗
PubMed1984

Development and validation of a method for measuring the glycine and taurine conjugates of bile acids in bile by high-performance liquid chromatography.

We developed and validated a simple method for measuring the individual glycine and taurine conjugates of bile acids in bile by high-performance liquid chromatography with a C18 reversed-phase column using an isocratic solvent system of acidified methanol--potassium phosphate. Without preliminary derivatization or purification, complete separation of the ten major conjugated bile acids present in bile could be achieved in 65 min. Total bile acid concentrations were identical when measured enzymatically and by summing the individual bile acids determined by high-performance liquid chromatography. Bile acid composition determined by gas-liquid chromatography correlated with results by high-performance liquid chromatography. Finally, measurements of individual glycine and taurine conjugates in human bile and in mixtures of bile acid standards by high-performance liquid chromatography and thin-layer chromatography gave similar results. This high-performance liquid chromatographic system permits simultaneous quantification of total and individual bile acids and their glycine and taurine conjugates in bile.

Bile↗
PubMed1984

Inherited deficiency of the Mac-1, LFA-1, p150,95 glycoprotein family and its molecular basis.

Leukocyte surface glycoproteins that share a common beta subunit have been found to be congenitally deficient in three unrelated patients with recurring bacterial infection. The glycoproteins, Mac-1, LFA-1, and p150,95, have the subunit compositions alpha M beta, alpha L beta, and alpha X beta, respectively. Using subunit-specific monoclonal antibodies, both the alpha M and beta subunits of Mac-1, the alpha L and beta subunits of LFA-1, and at the least the beta subunit of p150,95, were found to be deficient at the cell surface by the techniques of immunofluorescence flow cytometry, radioimmunoassay, and immunoprecipitation. A latent pool of Mac-1 that can be expressed on granulocyte surfaces in response to secretory stimuli, such as f-Met-Leu-Phe, was also lacking in patients. Deficiency was found on all leukocytes tested, including granulocytes, monocytes, and T and B lymphocytes. Quantitation by immunofluorescence cytometry of subunits on granulocytes from parents of these patients and of a fourth deceased patient showed approximately half-normal surface expression, and, together with data on other siblings and a family with an affected father and children, demonstrate autosomal recessive inheritance. Deficiency appears to be quantitative rather than qualitative, with two patients expressing approximately 0.5% and one patient approximately 5% of normal amounts. The latter patient had alpha beta complexes on the cell surface detectable by immunoprecipitation. Biosynthesis experiments showed the presence of normal amounts of alpha'L intracellular precursor in lymphoid lines of all three patients. Together with surface deficiency of three molecules that share a common beta subunit but have differing alpha subunits, this suggests the primary deficiency is of the beta subunit. The lack of maturation of alpha'L to alpha L and the deficiency of the alpha subunits at the cell surface and in latent pools suggests that association with the beta subunit is required for alpha subunit processing and transport to the cell surface or to latent pools. The molecular basis of this disease is discussed in light of adhesion-related functional abnormalities in patients' leukocytes and the blockade of similar functions in healthy cells by monoclonal antibodies.

Adolescent↗
PubMed1984

Stress-induced inhibition of sexual behavior: corticosterone inhibits courtship behaviors of a male amphibian (Taricha granulosa).

When male rough-skinned newts (Taricha granulosa) are exposed to presumptive stressors, the incidence of courtship decreases and plasma corticosterone concentration increases. When sexually active males are injected intraperitoneally with corticosterone (1, 5, 10, 15, 20, or 25 micrograms), the incidence of courtship decreases rapidly and in proportion to the dose of corticosterone. Intracerebroventricular infusion of synthetic corticotropin-releasing factor (CRF) elevates plasma corticosterone levels and suppresses courtship. When male newts receive an injection of metyrapone, a drug that interferes with corticosterone synthesis, the inhibitory effects of stress or CRF infusion on courtship are reduced. These results support the hypothesis that, in this amphibian, elevated levels of corticosterone associated with exposure to stressful stimuli inhibit sexual behaviors.

Adrenocorticotropic Hormone↗
PubMed1984

Characterization of cholecystokinin from the human brain.

Human forms of cholecystokinin have not previously been characterized chemically. In this study, we have extracted and purified the predominant molecular form of cholecystokinin present in human cerebral cortex. The peptide was characterized by amino acid analysis, automated peptide sequencing, and fast atom bombardment mass spectrometry. It appears to be identical to porcine cholecystokinin-octapeptide, with the sequence of Asp-Tyr(SO3)-Met-Gly-Trp-Met-Asp-Phe(NH2). This structural identity is consistent with the observations that the peptide in human brain and porcine cholecystokinin-octapeptide are recognized similarly by a battery of antisera to porcine cholecystokinin; that they coelute from several chromatographic systems, including gel filtration, ion exchange, and reversed-phase; and that they possess similar biological activities.

Brain Chemistry↗
PubMed1984

Characterization of cholecystokinin receptors on human gastric smooth muscle tumors.

Gastric smooth muscle cells are a physiological target for the polypeptide hormone cholecystokinin (CCK). Human tumors arising from this type of cell, leiomyosarcomas, can retain their ability to express a receptor for CCK. To begin to characterize the human CCK receptor, we established a scheme for fractionation of these tumors to yield a membrane preparation enriched in enzyme markers of plasmalemma that saturably binds CCK. In competition-binding studies using 125I-CCK-8, only peptides structurally related to CCK competed for binding, with 50% of binding inhibited by 0.075 nM CCK-8, 0.9 nM CCK-8-desulfate, 0.9 nM gastrin-17, and 2.5 nM CCK tetrapeptide. Specificity of binding was demonstrated by showing that structurally unrelated peptides did not compete for binding. Association and dissociation of binding were temperature dependent. We have also performed affinity labeling studies to define the molecular properties of the CCK binding site. In these, the membranes were incubated with 125I-CCK-33, washed, cross-linked with disuccinimidyl suberate, solubilized, and electrophoretically separated on a polyacrylamide gel. Autoradiography of the dried gel revealed labeling of a major component with Mr 75,000 and minor components with Mr 53,000, Mr 100,000, Mr 120,000, and Mr greater than 200,000. Labeling was inhibited by CCK-8 in a concentration-dependent manner. This was also specific for CCK and structurally related peptides. These results demonstrate that gastric leiomyosarcomas are a very good source of a human CCK receptor and suggest that they may provide an easily cultured tissue with which this receptor can be fully characterized.

Adult↗
PubMed1983

Lysis of inducer T cell clones by activated macrophages and macrophage-like cell lines.

We describe a sequence of reciprocal interactions between cloned inducer T cells and antigen-presenting cells (APC) that results in selective depletion of the antigen-reactive inducer cells. We show that corecognition of antigen and I-A by hapten-reactive inducer T cell clones results in (a) release of macrophage-activating factor (MAF) and other lymphokines, (b) expression of lytic activity by a subset of MAF-sensitized APC after triggering, and (3) lysis (mediated by the activated and triggered macrophage) of the inducer T cell clone and other cells in the vicinity. We suggest that this sequence of steps may limit the extent of macrophage-mediated tissue destruction by depleting the specific inducer T cell clones that initiate the response.

Animals↗
PubMed1983

Issues for informed consent.

Informed consent from a cytapheresis donor is the culmination of a complex decision making process during which the blood collecting agency presents sufficient information to enable the donor to make a free choice whether or not to donate. The institution bears the responsibility for providing all information relevant to the donor's decision, whether favorable or unfavorable. At no other stage of its contact with the donor can a collecting agency discharge its public trust more meaningfully. Thus, informed consent is not only the greatest altruistic expression from the unrelated volunteer donor, or the expression of deepest commitment to the family for the related donor, it is also the fullest expression of the value which the institute places on the autonomy of the donor. The foundation upon which the concept of informed consent rests has been laid by law, medicine, government, ethics, and religion. Although the procedures accompanying the informed consent process appear bureaucratic, they should be viewed as the components of a remarkable, dynamic process. The consent of a donor to undergo cytapheresis is an eloquent statement of the value he or she places on the importance of another human being's life.

Blood Component Removal↗
PubMed1983

Adenocarcinoma of the rectum arising in a hamartomatous polyp in a patient with Peutz-Jeghers syndrome.

The malignant potential of the hamartomatous polyps in Peutz-Jeghers syndrome has been debated. Although this is a very rare event, these polyps can undergo carcinomatous transformation, as demonstrated by this report of a 37-year-old man with well-documented Peutz-Jeghers syndrome who developed an invasive grade 2 adenocarcinoma on the surface of a hamartomatous polyp in the rectum.

Adenocarcinoma↗
PubMed1983

Identification and localization of cholecystokinin-binding sites on rat pancreatic plasma membranes and acinar cells: a biochemical and autoradiographic study.

Using the combined approaches of affinity labeling and light and electron microscopic autoradiography, we investigated the identification and localization of cholecystokinin (CCK)-binding sites on rat pancreatic acinar cells. To define the molecular properties of the CCK-binding site, we incubated rat pancreatic plasma membranes with 125-I-CCK-33 for 15 min at 23 degrees C followed by washing and cross-linking with disuccinimidyl suberate. Specific labeling of a major Mr 85,000 component was revealed as assessed by SDS PAGE under reducing conditions and autoradiography of the dried gels. Components of Mr greater than 200,000, Mr 130,000-140,000, and, Mr 55,000 were labeled under maximal cross-linking conditions. The labeling of all components was specifically inhibited by CCK-8 in a dose-dependent manner (Kd approximately 9 nM). The Mr 85,000 component had identical electrophoretic mobilities under reducing and nonreducing conditions indicating that it likely does not contain intramolecular disulfide bonds. The larger labeled species may be cross-linked oligomers of this binding protein or complexes between it and neighboring polypeptides. For studies on the distribution of CCK-binding sites, pancreatic acini were incubated with 125I-CCK-33 (0.1 nM) in the absence or presence of CCK-8 (1 microM) for 2 or 15 min at 37 degrees C, washed, and fixed in 2% glutaraldehyde. Quantitative autoradiographic analysis indicated that approximately 60% of the total grains were located within +/- 1 HD (1 HD = 100 nm) of the lateral and basal plasmalemma with little or no labeling of the apical plasmalemma. From these data, it was estimated that each acinar cell possesses at least 5,000-10,000 CCK-binding sites on its basolateral plasmalemma. The remaining grains showed no preferential concentration over the cytoplasm or nucleus. Together, these data indicate that CCK interacts with a Mr 85,000 protein located on the basolateral plasmalemma of the pancreatic acinar cell.

Affinity Labels↗
PubMed1983

Effect of graded intraduodenal glucose infusions on the release and physiological action of gastric inhibitory polypeptide.

Gastric inhibitory polypeptide (GIP) is the leading candidate for gut hormonal augmentation of insulin release. The release of its subspecies (mol wt, 5000 and 7500) and the physiological action of total immunoreactive GIP (IR-GIP) were investigated during isotonic glucose infusions at 75, 225, and 465 mg/min in nine volunteers. Each dose was infused intraduodenally and iv in the same volunteer. Intestinal augmentation of insulin release occurred during the high dose intraduodenal glucose infusion (P less than 0.001) but not during the lower doses. An elevation of 17-20 mg/dl in plasma glucose was required before this insulinotropic effect occurred (P less than 0.001). At increments of plasma glucose above 17 mg/dl, the augmentation of gut-mediated insulin release was dependent on the degree of hyperglycemia (r = 0.81; P less than 0.01). At each dose of intraduodenally administered glucose, IR-GIP was elevated within 20-40 min (P less than 0.01), remaining at a steady level until the infusion was stopped. The release of IR-GIP was elevated within 20-40 min (P less than 0.01), remaining at a steady level until the infusion was stopped. The release of IR-GIP was proportional to the intestinal glucose load but was unchanged from the basal level during iv glucose studies. The attained IR-GIP levels remained constant in each study despite large variations over time in plasma glucose and insulin concentrations. During intestinal glucose infusion, 58.7 +/- 4.1% of IR-GIP was accounted for by the 5000 mol wt subspecies and 17.3 +/- 3.5% was accounted for by the 7500 mol wt subspecies, with the remaining immunoreactivity found in the void volume of a Sephadex G-50 column. Relative proportions remained constant throughout the 4-h study. Thus, during glucose stimulation, the total IR-GIP released 1) is proportional to the absorbable luminal stimulus, 2) is independent of ambient plasma insulin and glucose levels, 3) is composed predominantly of the 5000 mol wt form, and 4) requires an elevation in plasma glucose of 17-20 mg/dl before it augments insulin release, but then stimulates insulin release in a fashion linearly dependent upon the increment in plasma glucose.

Adult↗
PubMed1983

A soluble interaction between dibutyryl cyclic guanosine 3':5'-monophosphate and cholecystokinin: a possible mechanism for the inhibition of cholecystokinin activity.

N2,O2'-dibutyryl cyclic guanosine 3':5'-monophosphate has been reported to inhibit the activity of cholecystokinin on several different end organ responses and in several species. Although the mechanism of this inhibition is unclear, competitive antagonism at the level of the receptor has been suggested. We have investigated an alternate possibility, that N2,O2'-dibutyryl cyclic guanosine 3':5'-monophosphate inhibits cholecystokinin action by interacting directly with the peptide while both are in solution. We used antisera with specificities for different regions of cholecystokinin-gastrin peptides and radioiodinated cholecystokinin-33, cholecystokinin-8, and gastrin-17. Our results support the possibility of a soluble interaction between N2,O2'-dibutyryl cyclic guanosine 3':5'-monophosphate and the peptides of cholecystokinin-gastrin family that is specific for the COOH-terminal (receptor binding) region of these peptides, that is dependent on the concentration of N2,O2'-dibutyryl cyclic guanosine 3':5'-monophosphate, and that correlates with concentrations that inhibit biologic activity. The proposed N2,O2'-dibutyryl cyclic guanosine 3':5'-monophosphate-cholecystokinin complex is dispersed by gel filtration chromatography, and is prevented from being formed by certain detergents.

Antigen-Antibody Reactions↗