Nutritional aspects of manganese from experimental studies.

In experimental animals, dietary manganese deficiency can result in numerous biochemical and structural abnormalities. Deficient animals can be characterized by impaired insulin production, alterations in lipoprotein metabolism, an impaired oxidant defense system, and perturbations in growth factor metabolism. If the deficiency occurs during early development, there can be pronounced skeletal abnormalities and an irreversible ataxia.

Inhibitory effects of combinations of HER-2/neu antibody and chemotherapeutic agents used for treatment of human breast cancers.

Previous studies have demonstrated a synergistic interaction between rhuMAb HER2 and the cytotoxic drug cisplatin in human breast and ovarian cancer cells. To define the nature of the interaction between rhuMAb HER2 and other classes of cytotoxic drugs, we applied multiple drug effect/combination index (CI) isobologram analysis to a variety of chemotherapeutic drug/rhuMAb HER2 combinations in vitro. Synergistic interactions at clinically relevant drug concentrations were observed for rhuMAb HER2 in combination with cisplatin (CI=0.

A sensitive fluorometric enzyme-linked immunosorbent assay that measures vascular endothelial growth factor165 in human plasma.

A specific and sensitive fluorometric enzyme-linked immunosorbent assay (ELISA) was developed to measure endogenous levels of vascular endothelial growth factor (VEGF165) in human plasma. The ELISA can be performed in 10% human EDTA plasma, yielding a neat plasma sensitivity of 10 pg/ml or 0.2 pM.

A His19 to Ala mutant of melanoma growth-stimulating activity is a partial antagonist of the CXCR2 receptor.

Melanoma growth stimulating activity (MGSA) and IL-8 are related chemokines that are potent chemoattractants and activators of neutrophils both in vitro and in vivo. Increasing evidence suggests that these molecules play an important role in inflammation; thus, antagonists of their action could be useful therapeutically as antiinflammatory agents. We have generated an MGSA mutant, H19A, that shows a dissociation between receptor binding and biologic activity.

The influence of manganese deficiency on serum IGF-1 and IGF binding proteins in the male rat.

Young male rats subjected to a dietary manganese (Mn) deficiency respond to the deficiency by reducing their growth rate. The growth hormone (GH)/insulin-like growth factor (IGF) axis is critical for linear growth; this system is exquisitely sensitive to the nutritional state of the animal. In this study, we examined circulating GH, IGF-1, and insulin levels in Mn-deficient (-Mn; fed a 0.

Phase II study of receptor-enhanced chemosensitivity using recombinant humanized anti-p185HER2/neu monoclonal antibody plus cisplatin in patients with HER2/neu-overexpressing metastatic breast cancer refractory to chemotherapy treatment.

Purpose: To determine the toxicity, pharmacokinetics, response rate, and response duration of intravenous (i.v.) administration of recombinant, humanized anti-p185HER2 monoclonal antibody (rhuMAb HER2) plus cisplatin (CDDP) in a phase II, open-label, multicenter clinical trial for patients with HER2/neu-overexpressing metastatic breast cancer.

Transforming growth factor-beta 1, macrophage inflammatory protein-1 alpha, and interleukin-8 gene expression is lower in stimulated human neonatal compared with adult mononuclear cells.

Hematopoiesis is developmentally immature in the newborn compared with the adult. Diminished gene expression of several positive hematopoietic regulators has been observed in activated cord compared with adult peripheral blood mononuclear cells (MNC; Cairo et al. Pediatr Res, 30:362, 1991 and Cairo et al, Pediatr Res, 31:574, 1992).

Effect of chronic IL-1 beta infusion on glucose homeostasis and pancreatic insulin secretion.

The present studies examined the effects of chronic interleukin-1 (IL-1 beta) infusion on glucose homeostasis and insulin secretion in male Sprague Dawley rats. IL-1 beta (4 micrograms per day) or saline was infused over a six day period using mini-osmotic pumps, surgically inserted under light ether anesthesia. Saline-infused rats were fed the amount of food consumed by their respective pair in the IL-1 beta group on the previous day.

Quantitative two-site enzyme-linked immunosorbent assays for inhibin A, activin A and activin B.

We have developed three specific enzyme-linked immunosorbent assay (ELISA) formats which quantitate inhibin A in conditioned media and serum. The assays are sensitive in a range 0.078-5.

Development of a specific and sensitive two-site enzyme-linked immunosorbent assay for measurement of inhibin-A in serum.

A polyclonal chicken antiserum against purified 32-kilodalton (kDa) recombinant inhibin-A (rh-InhA) and two monoclonal antibodies (mAb) against either rh-InhA (11B5) or 28-kDa recombinant activin-A (rh-ActA; 9A9) were used to develop three sensitive InhA enzyme-linked immunosorbent assays (ELISAs). The sensitivity of an ELISA using affinity-purified chicken anti-rh-InhA (Ck) for both coat and capture (Ck/Ck) averaged 78 +/- 3 pg/ml, while the mAb/Ck ELISAs (11B5/Ck or 9A9/Ck) averaged 100 +/- 6 pg/ml in a 10% serum matrix, with intra-and interassay coefficients of variation of 2-5% and 8-10%, respectively, for all assays. The ELISA formats did not cross-react with purified rh-ActA or recombinant human transforming growth factor-beta 1 or detect any immunoreactive proteins in medium conditioned by cell lines expressing rh-ActA or recombinant human transforming growth factor-beta 1.

Pharmacokinetic profile of recombinant human (rh) inhibin A and activin A in the immature rat. I. Serum profile of rh-inhibin A and rh-activin A in the immature female rat.

The serum pharmacokinetics of recombinant human inhibin A (rh-inhibin A) and rh-activin A were examined in immature female Sprague Dawley-derived rats after iv and sc injection of the drugs. After iv administration of rh-inhibin A (120 micrograms/kg), the serum concentrations were described by a biexponential equation. The weight-normalized clearance was 21.

Identification and characterization of binding proteins for inhibin and activin in human serum and follicular fluids.

Inhibins and activins are produced by a variety of tissues and may have important endocrine and paracrine roles in development, reproduction, and hematopoiesis. However, little is known regarding the physical properties or concentrations of inhibin and activin in biological fluids. Binding proteins for inhibin or activin in serum or at production or target sites may have important implications for restricting the bioactivity of these hormones and may alter the immunoreactivity of these molecules in biological fluids.

Interleukin-1 stimulates glucose transport in rat adipose cells. Evidence for receptor discrimination between IL-1 beta and IL-1 alpha.

The effect of interleukin 1 (IL-1) on glucose transport activity in isolated rat adipose cells was examined. IL-1 beta stimulated 3-O-methylglucose (3OMG) transport in a time and dose dependent manner. This effect appears to be due to increased maximal transport velocity (Vmax) of the carrier.

Effect of manganese deficiency on insulin binding, glucose transport and metabolism in rat adipocytes.

The effect of manganese deficiency on insulin binding, glucose transport and metabolism in isolated adipose cells from Sprague-Dawley rats was investigated. Offspring from Mn-sufficient female rats fed 45 micrograms Mn/g diet (control) and from Mn-deficient (Mn-) female rats fed 1 microgram Mn/g diet were used in these studies. Both basal and insulin-stimulated 3-O-methylglucose transport in isolated adipose cells was significantly lower in Mn- rats, averaging 40% and 50% of control values, respectively.

Mechanism of decreased insulinogenesis in manganese-deficient rats. Decreased insulin mRNA levels.

Manganese-deficient rats exhibited seven-fold lower preproinsulin mRNA levels compared to control, as detected by dot blot hybridization of both total and poly(A)+ RNA using a preproinsulin cDNA probe. No differences in the size of the insulin mRNA were observed. Thus, decreased mRNA levels may be a major contributing factor to the decreased insulinogenesis observed in manganese-deficient rats.

Dissociation of insulin-stimulated glucose transport from the translocation of glucose carriers in rat adipose cells.

Cycloheximide, a potent inhibitor of protein synthesis, has been used to examine the relationship between recruitment of hexose carriers and the activation of glucose transport by insulin in rat adipocytes. Adipocytes were preincubated +/- cycloheximide for 90 min then +/- insulin for a further 30 min. We measured 3-O-methylglucose uptake in intact cells and in isolated plasma membrane vesicles.

Effects of manganese deficiency on pyruvate carboxylase and phosphoenolpyruvate carboxykinase activity and carbohydrate homeostasis in adult rats.

The activities of two liver gluconeogenic enzymes, pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK), as well as liver glycogen and plasma glucose, insulin, and glucagon were measured in first- and second-generation, manganese-sufficient (control) and manganese-deficient (Mn-) adult rats. Pyruvate carboxylase activity of first generation male Mn- rats was higher than that of controls in both the fed and fasted states. In contrast, PC activity in second generation male Mn- rats was lower than control levels.

Rapid and effective transfer of integral membrane proteins from isoelectric focusing gels to nitrocellulose membranes.

A method describing the rapid and effective transfer of integral membrane protein from isoelectric focusing gels to nitrocellulose is described. Initial experiments were carried out with detergent-solubilized extracts of human erythrocyte membrane proteins. The effectiveness of the transfer was demonstrated by assaying for erythrocyte glucose transporter, an integral membrane protein, using specific antibodies followed by 125I-protein A and autoradiography.

Biochemical and functional heterogeneity of rat adipocyte glucose transporters.

We have studied the biochemical mechanism of insulin action on glucose transport in the rat adipocyte. Plasma membranes and low-density microsomes were prepared by differential ultracentrifugation of basal and insulin-stimulated cells. The photochemical cross-linking agent hydroxysuccinimidyl-4-azidobenzoate was used to covalently bind [3H]cytochalasin B to the glucose transporter which migrated as a 45-50-kDa protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Pyruvate carboxylase and phosphoenolpyruvate carboxykinase activity in developing rats: effect of manganese deficiency.

The activities of two liver gluconeogenic enzymes, pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) as well as plasma glucose were measured in manganese-sufficient and manganese-deficient rats from birth to 30 d of age. Initial (d 0) PC activity was similar in the two groups. PC activity increased 1.

Dynamics of insulin and glucagon release in rats: influence of dietary manganese.

The effect of manganese on endocrine pancreatic function was examined in manganese-sufficient (control) and manganese-deficient (Mn-) Sprague-Dawley rats. Pancreatic insulin release was lower (P less than 0.05) in Mn- rats than in controls in response to both a 300 mg/dl and a 100 mg/dl glucose stimulus.

Effects of high doses of manganese on carbohydrate homeostasis.

The effects of manganese (Mn) toxicity on carbohydrate homeostasis was examined in Sprague-Dawley and Osborne-Mendel rats. Mn injection was followed by increases in Mn concentration in both liver and pancreas. Concentrations of Mn in the pancreas increased more rapidly than in the liver.