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Showing papers by "Eli Lilly and Company published in 1990"


Journal ArticleDOI
01 Jun 1990-Science
TL;DR: Direct protein structural analyses showed that constitutive processing in human embryonic kidney 293 cells cleaves APP in the interior of the A Beta P, thus preventing A beta P deposition.
Abstract: The amyloid beta peptide (A beta P) is a small fragment of the much larger, broadly distributed amyloid precursor protein (APP). Abundant A beta P deposition in the brains of patients with Alzheimer's disease suggests that altered APP processing may represent a key pathogenic event. Direct protein structural analyses showed that constitutive processing in human embryonic kidney 293 cells cleaves APP in the interior of the A beta P, thus preventing A beta P deposition. A deficiency of this processing event may ultimately prove to be the etiological event in Alzheimer's disease that gives rise to senile plaque formation.

1,449 citations


Journal Article
TL;DR: DFdCyd demonstrated good to excellent antitumor activity in eight of the eight murine tumor models evaluated and is an excellent candidate for clinical trials in the treatment of cancer.
Abstract: A new pyrimidine antimetabolite, 2',2'-difluorodeoxycytidine, Gemcitabine (LY188011, dFdCyd) has been synthesized and evaluated in experimental tumor models. dFdCyd is a very potent and specific deoxycytidine analogue. The concentration required for 50% inhibition of growth is 1 ng/ml in the CCRF-CEM human leukemia cell culture assay. Concurrent addition of deoxycytidine to the cell culture system provides about a 1000-fold decrease in biological activity. The inhibition of growth of human leukemia cells in culture led to the in vivo evaluation of this compound as a potential oncolytic agent. Maximal activity in vivo was seen with dFdCyd when administered on an every third day schedule. 1-beta-D-Arabinofuranosylcytosine, administered on a daily for 10-day schedule, was directly compared to dFdCyd in this evaluation. dFdCyd demonstrated good to excellent antitumor activity in eight of the eight murine tumor models evaluated. 1-beta-D-Arabinofuranosylcytosine was substantially less active or had no activity in these same tumor models. This in vivo activity against murine solid tumors supports the conclusion that dFdCyd is an excellent candidate for clinical trials in the treatment of cancer.

700 citations


Journal ArticleDOI
TL;DR: The advent of new pharmacological tools, in particular the selective agonist trans-ACPD, has now allowed this receptor to be distinguished pharmacologically, and the new data can be correlated to functional responses and linked with physiological and pathological conditions.

490 citations


Journal Article
TL;DR: It was observed that P450IIIA5 was detected in a statistically significantly higher percentage of children and adolescents (19 years old and under), as compared with the remaining population (8 of 17, 47%, versus 11 of 46, 24%, respectively).
Abstract: The human P450III family has been shown to be composed of at least four members, P450IIIA3 (HLp), P450IIIA4 (P450NF), P450IIIA5 (HLp3), and P450IIIA6 (HLp2). Due to the lack of probes that specifically recognize the individual members of this family, little is known about their relative expression. We prepared a form-specific antibody to P450IIIA5 by immunoabsorption of anti-P450IIIA5 IgG against Sepharose 4B upon which microsomes that did not contain P450IIIA5 or purified P450IIIA3 had been bound. Immunoblot analyses demonstrated that P450IIIA5 was expressed at detectable levels in only 19 of 66 (29%) human livers. The expression of P450IIIA5 was not influenced by the gender or medical history of the patients. When the expression of P450IIIA5 in different age groups was examined, it was observed that P450IIIA5 was detected in a statistically significantly higher percentage of children and adolescents (19 years old and under), as compared with the remaining population (8 of 17, 47%, versus 11 of 46, 24%, respectively). Furthermore, P450IIIA5 was detected in 1 of 10 human fetal livers. Of the large number of compounds identified as substrates of P450III family members, P450IIIA5 was found to actively metabolize nifedipine, testosterone, estradiol, dehydroepiandrosterone 3-sulfate, and cortisol, whereas it metabolized poorly or did not metabolize erythromycin, quinidine, 17 alpha-ethynylestradiol, and aflatoxins. The acetylenic steroid gestodene was found to be an effective mechanism-based inhibitor of both P450IIIA4 and P450IIIA5. Immunoblots of microsomes isolated from untreated and dexamethasone-, phenobarbital-, or 3-methylcholanthrene-treated HepG2 cells that were developed with an antibody that recognizes all the P450III family members demonstrated that no proteins in the P450III family were expressed by the HepG2 cells. In conclusion, our studies indicate that P450IIIA5 is polymorphically expressed at all stages of human development and is more limited in its metabolic capabilities than is P450IIIA4.

422 citations


Journal ArticleDOI
TL;DR: The studies in animals suggest that while there are certain similarities in the behavioral effects of PCP-like and competitive antagonists, there are also differences that have implications for the development of NMDA antagonists with less likelihood for producing PCp-like side-effects.

321 citations


Journal ArticleDOI
TL;DR: In this article, a theoretical analysis of the collapse temperature of moxalactam di-sodium with 12% mannitol is presented, and a quantitative model based on these concepts is developed with key parameters being evaluated by experimental studies.

277 citations


Journal ArticleDOI
TL;DR: The transport of the orally absorbed cephalosporin, cephalexin, was examined in the human epithelial cell line, Caco-2 that possesses intestinal enterocyte-like properties when cultured to represent a cellular model for future studies of the dipeptide transporter.

223 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of temperature and chamber pressure on secondary drying were analyzed using a vacuum microbalance and by Karl Fischer assay of vials sealed at selected times during secondary drying experiments conducted in a laboratory scale freeze dryer.

213 citations


Journal Article
TL;DR: It is concluded that a dose rate of greater than 400 mg/m2/h was required to achieve plasma dFdC levels that supported the maximum rate of dFDCTP accumulation in leukemia cells.
Abstract: The objective of this study was to determine the dose rate of 2',2'-difluorodeoxycytidine (dFdC) that maximizes the accumulation of the active 5'-triphosphate (dFdCTP) in circulating leukemia cells during therapy. The investigational approach was to evaluate the relationship between plasma dFdC and the accumulation of dFdCTP by circulating leukemia cells during infusion of different dFdC dose rates in the same individuals. Four patients with relapsed leukemia were treated weekly with two or three consecutive infusions of 800 mg/m2, the first administered over 1 h, the second over 2 h, and the third over 3 h. Two patients, one with acute myelogenous leukemia and one with acute lymphocytic leukemia, received all three infusions, but thrombocytopenia prohibited infusion of the third dose to two patients with chronic lymphocytic leukemia. The average steady-state plasma dFdC levels, achieved within 15 min after the infusion began, were 43.8 microM during infusion of 800 mg/m2/h, 9.4 microM during infusion of 400 mg/m2/h, and 5.6 microM at 267 mg/m2/h. The median area under the concentration times time curve of dFdCTP in leukemia cells during infusion was increased 2.3- and 5.1-fold for the 2- and 3-h infusions, respectively. In vitro incubations of leukemia cells from the four patients with 2.5-100 microM dFdC for 1 h showed that the maximum cellular accumulation of dFdCTP was produced by 15-20 microM dFdC. We conclude that a dose rate of greater than 400 mg/m2/h was required to achieve plasma dFdC levels that supported the maximum rate of dFdCTP accumulation in leukemia cells.

207 citations



Journal ArticleDOI
TL;DR: The r65- kD protein appears to produce an antigen-specific protection against arthritis induced by bacterial cell walls containing the 65-kD protein, suggesting that protection occurs by preventing clonal proliferation of autoreactive T lymphocytes that are induced by the adjuvant properties of mycobacterial cell walls.
Abstract: A recombinant (r)65-kD protein from Mycobacterium leprae, at levels far in excess of those present in whole mycobacteria, was unable to induce arthritis. Even when combined with a synthetic adjuvant, CP20961, to mimic the peptidoglycan adjuvant component of the mycobacterial cell wall, the r65-kD protein failed to induce arthritis. Pretreatment with as little as 1 microgram r65-kD protein protected rats against arthritis induced by M. tuberculosis, but this r65-kD protein was markedly less able to protect against arthritis induced by the synthetic adjuvant, CP20961, or type II collagen. The r65-kD protein appears, therefore, to produce an antigen-specific protection against arthritis induced by bacterial cell walls containing the 65-kD protein. Such protection can be overcome, however, by arthritogenic T lymphocytes, suggesting that protection occurs by preventing clonal proliferation of autoreactive T lymphocytes that are induced by the adjuvant properties of mycobacterial cell walls. How the r65-kD protein abrogates this particular adjuvant activity, and the nature of the arthritogenic self antigen(s), remain to be elucidated.

Journal ArticleDOI
TL;DR: Some serotonin uptake inhibitors are finding therapeutic uses in mental depression and other psychiatric disorders and in treating obesity and bulimia; other therapeutic applications continue to be evaluated.
Abstract: Serotonin uptake carriers occur on serotonin neurons, on glial cells and on blood platelets. The uptake carrier on serotonin neurons inactivates serotonin that has been released into the synaptic cleft by transporting it back into the nerve terminal. The serotonin uptake carrier is the means by which blood platelets acquire serotonin, since they do not synthesize it. The function of the serotonin uptake carrier on glial cells is poorly understood. Selective inhibitors of serotonin uptake enhance neurotransmission via serotonergic neurons and have been useful pharmacologic tools for studying physiologic roles of serotonin neurons. Some serotonin uptake inhibitors are finding therapeutic uses in mental depression and other psychiatric disorders and in treating obesity and bulimia; other therapeutic applications continue to be evaluated.

Patent
04 Apr 1990
TL;DR: In this article, a multi-dose syringe with a window through which only a segment of the dose-indicating scale on said portion is visible, the visible portion indicating the amount of liquid selected for injection.
Abstract: Two embodiments of a multi-dose syringe both include structure for indicating the selected amount of liquid to be injected. A first element and a second element coupled respectively to the syringe housing and the plunger rod are adapted for calibrated movement with respect to each other, one of the first and second elements includes an outer portion having dose-indicating scale thereon, and another of the first and second elements surrounding said outer portion includes a window through which only a segment of the dose-indicating scale on said portion is visible, the visible portion indicating the amount of liquid selected for injection.

Journal ArticleDOI
TL;DR: It is demonstrated that both the γ-carboxyglutamate and glycosyl contents affect the functional activities of rHPC, and the critical dependence of full γ -carboxylation on the function of this protein is demonstrated.
Abstract: Human Protein C (HPC), an antithrombotic factor with potential clinical utility, is a vitamin K-dependent protein that has several complex post-translational modifications. In an effort to define the functional roles of these modifications, recombinant HPC (rHPC) was expressed in and characterized from 3 adenovirus-transformed cell lines. The rHPC in crude culture medium from the 3 cell lines displayed anticoagulant activities that were either higher, slightly lower or much lower than that of plasma HPC. The rHPC from each cell line was purified and characterized using a novel, but simple chromatographic method, termed "pseudo-affinity", capable of resolving molecules differing by only very slight modifications. We demonstrate the critical dependence of full gamma-carboxylation on the function of this protein. In addition, our data indicate that both the gamma-carboxyglutamate and glycosyl contents affect the functional activities of rHPC.

Journal ArticleDOI
TL;DR: In this paper, transcardiac shocks of up to 30 J or pacing stimuli were delivered to myocardial tissue at different times in the electrical cycle, and there was a positive correlation between both the shock energy and timing and the amount of delay.
Abstract: In pentobarbital-anesthetized dogs, transcardiac shocks of up to 30 J or pacing stimuli were delivered to myocardial tissue at different times in the electrical cycle. When delivered midway or later into electrical systole, shocks, but not pacing stimuli, greatly extended the refractory period as determined by left ventricular pacing. There was a positive correlation between both the shock energy and timing and the amount of delay. A 30-J shock given 10 msec before the end of the refractory period extended the refractory period by 63 +/- 15 msec (p less than 0.001), whereas the same shock given 40 msec earlier produced only 25 +/- 10 msec (p less than 0.001) of extension. By comparison, a 5-J shock given at those times produced 36 +/- 18 (p less than 0.005) and 10 +/- 8 msec (p less than 0.001) of extension, respectively. When delivered early into electrical systole, both a pacing stimulus and a shock had no substantial effect on the tissue refractory period. Because the tissue that is late in electrical systole would otherwise be the first to repolarize if no shock were given, the selective refractory period extension may create a period after the shock during which no tissue is repolarized to a level sufficient for wavefront propagation. Thus, the energy- and time-dependent refractory period extension may help explain the mechanism by which ventricular defibrillation occurs during transcardiac shocks.

Journal ArticleDOI
TL;DR: A series of diarylsulfonylureas with exceptionally broad-spectrum activity against syngeneic rodent solid tumors in vivo is described, and one compound from the series has progressed to Phase I clinical trials as an antitumor drug.
Abstract: A series of diarylsulfonylureas with exceptionally broad-spectrum activity against syngeneic rodent solid tumors in vivo is described. Their discovery resulted from a program dedicated to in vivo screening for novel oncolytics in solid tumor models, rather than traditional ascites leukemia models. The structures, oral efficacy, side-effect profile, and mechanism of action of these sulfonylureas appear to be distinct from previously known classes of oncolytics. An extensive series of analogues was prepared to probe structure-activity relationships (SAR), with particular focus on the substituent patterns of each aryl domain. Quantitative analysis of these substituent SARs, using the method of cluster significance analysis, showed the lipophilicity of the substituents to be the dominant determinant of activity. One compound from the series, LY186641 (104, sulofenur), has progressed to Phase I clinical trials as an antitumor drug.

Journal ArticleDOI
TL;DR: Both electrical resistance and Jv data indicate changes in transport properties occur when HMS is subjected to an electric field, consistent with a small negative charge on the membrane at mid pH's and charge reversal around pH 4.3.
Abstract: Previous studies suggest that bulk fluid flow by electroosmosis is a significant factor in iontophoresis and may provide an explanation for the observed enhanced transport of neutral species. In a charged membrane, the solution carries a net charge and thus experiences a volume force in an electric field, which causes volume flow (Jv in the direction of counterion flow. Jv data were obtained for hairless mouse skin (HM) as a function of pH, concentration of NaCl, current density, and time. Volume flow was measured by timing fluid movement in horizontal capillary tubes attached to the anode and cathode (Ag/AgCl) compartments. By convention, the sign of Jv is taken as positive when the volume flow is in the same direction as positive current flow. Experimental mean values were in the range 0 to + 37 µl/cm2 hr, depending on the experimental conditions. Volume flow of this magnitude is large enough to have significant impact on flow of both ions and neutral species. The positive sign for Jv indicates that HMS is negative in the pH range studied (3.8–8.3). Jv decrease with time, decrease with increasing NaCl concentration, are much lower at pH 3.8 than at the higher pH's, and increase with current density. Effective transference numbers, determined from membrane potential measurements, showed significant pH dependence, consistent with a small negative charge on the membrane at mid pH's and charge reversal around pH 4. Both electrical resistance and Jv data indicate changes in transport properties occur when HMS is subjected to an electric field.


Journal ArticleDOI
TL;DR: This research develops a detailed theoretical model which allows the effect of volume flow on flux enhancement to be evaluated and results are consistent with data in the literature.
Abstract: Bulk fluid flow or volume flow in the direction of counterion flow is a probable mechanism for enhanced flux of uncharged species by iontophoresis. Both the electrical volume force effect, resulting from the interaction of the “ion atmosphere” and the electric field, and an induced osmotic pressure effect produce volume flow in the same direction as counterion flow through the membrane. Since each of these effects is proportional to the membrane charge and the imposed electric field, we classify both as electroosmotic flow. This research develops a detailed theoretical model which allows the effect of volume flow on flux enhancement to be evaluated. A detailed theoretical result for the electroosmotic flow coefficient also results from the analysis. The model assumes that transport occurs in three types of aqueous pores: positively charged, neutral, and negatively charged. For hairless mouse skin (HMS), pore size, charge, and number are evaluated from transference number, volume flow, and electrical resistance data. The flux enhancement ratio is J1/J1D= ΣAiαi/[l –exp( –αi)], where i = pore type, and the summation runs over the three pore types. Ai is the area fraction of pore type i effective for transport; J1 and J1D are flux of species 1 with and without the electric field, respectively; and αi is given by αi = F(–ΔΦ/RT)[ z1 + (−zmi)Bari2Cmi(Gi + F)]. Here F = Faraday's constant; −ΔΦ = voltage drop; R = gas constant; T = absolute temperature; zmi = charge of pore i; Cmi = charge concentration in membrane pore of radius, ri; B is a known collection of constants; a is the Stokes radius of the transported solute; Gi, is a function of membrane charge and pore radius coming from the electrical volume force effect; and F is a function of membrane charge and ion mobility arising from the induced osmotic pressure effect. For transdermal iontophoresis, F 0) or a neutral species (z1 = 0) in a negatively charged pore. The theoretical results are consistent with data in the literature.

Journal ArticleDOI
01 Oct 1990-Matrix
TL;DR: An enzyme-linked absorbent assay for the determination of hyaluronan (HA) has been developed and is based on a microtitre plate format and involves fewer experimental steps and is simpler to perform than other methods.

Journal ArticleDOI
TL;DR: In vitro transport data was provided to clarify the relative importance of permeability increase and electroosmotic flow in flux enhancement via iontophoresis, and agreement between theory and experiment was only qualitative in several cases, most of the data are predicted quantitatively by the theory.
Abstract: The objective of this research was to provide in vitro transport data designed to clarify the relative importance of permeability increase and electroosmotic flow in flux enhancement via iontophoresis, Iontophoretic fluxes were measured with both anode and cathode donor cells, and passive fluxes were measured both before iontophoresis (Passive 1) and after iontophoresis (Passive 2). Data were generated for three uncharged low molecular weight solutes (glycine, glucose, and tyrosine) and two high molecular weight anionic species (carboxy inulin and bovine serum albumin). Flux enhancement is greater for anodic delivery than for cathodic delivery, even for the negatively charged molecules, and anodic flux of glucose decreases as the concentration of NaCl increases. Both observations are consistent with a mass transfer mechanism strongly dependent on electroosmotic flow. Steady-state anodic flux at 0.32 mA/cm2, expressed as equivalent donor solution flux (in µl/hr cm2), ranged from 6.1 for glycine to about 2 for the large anions. As expected, iontophoretic flux is higher at 3.2 mA/cm2 than at 0.32 mA/cm2, and passive flux measured after iontophoresis is about a factor of 10 greater than the corresponding flux measured before the skin was exposed to electric current. There are two mechanisms for flux enhancement relative to passive flux on “fresh” hairless mouse skin: (1) the effect of the voltage in increasing mass transfer over the passive diffusion level, the effect of electroosmotic flow dominating this contribution in the systems studied in this report; and (2) the effect of prior current flow in increasing the “intrinsic permeability” of the skin. Both effects are significant. Based on theoretical results given elsewhere, theoretical values for flux were calculated and compared with the experimental data. While agreement between theory and experiment was only qualitative in several cases, most of the data are predicted quantitatively by the theory.

Journal Article
TL;DR: L-2-amino-3-phosphonopropionic acid is a stereoselective inhibitor of metabotropic excitatory amino acid receptors with little affinity for ionotropic receptors.
Abstract: DL-2-Amino-3-phosphonopropionic acid, a phosphonate-substituted derivative of aspartic acid, has been shown to be an inhibitor of excitatory amino acid-stimulated phosphoinositide hydrolysis in rat brain slices. In this study, the enantiomers of 2-amino-3-phosphonopropionic acid were synthesized and used to further characterize the stereoselectivity and mechanism of interaction of this compound for inhibiting phosphoinositide-coupled (metabotropic) excitatory amino acid receptors. L-2-Amino-3-phosphonopropionic acid was 3-5 times more potent than D-2-amino-3-phosphonopropionic acid as an inhibitor of ibotenate-stimulated [3H]inositol monophosphate formation in slices of the rat hippocampus or quisqualate-stimulated [3H]inositol monophosphate formation in neonatal rat cerebral cortical slices. Carbachol-stimulated phosphoinositide hydrolysis was not inhibited by L-2-amino-3-phosphonopropionic acid, and L-2-amino-3-phosphonopropionic acid had no appreciable affinity for ionotropic excitatory amino acid receptors at concentrations required to inhibit metabotropic excitatory amino acid responses. The inhibitory effects of L-2-amino-3-phosphonopropionic acid or L-2-amino-4-phosphonobutyric acid on phosphoinositide hydrolysis were not competitive, because they could not be surmounted by increasing concentrations of ibotenate or quisqualate. L-2-Amino-3-phosphonopropionic acid inhibition also could not be prevented by washing the tissue before incubation with ibotenate. Thus, L-2-amino-3-phosphonopropionic acid is a stereoselective inhibitor of metabotropic excitatory amino acid receptors with little affinity for ionotropic receptors. However, the inhibitory effects of L-2-amino-3-phosphonopropionic acid or L-2-amino-4-phosphonobutyric acid were not readily reversed, and the site at which they act to inhibit metabotropic excitatory amino acid receptors remains to be determined.

Book ChapterDOI
TL;DR: In this article, different methods of producing and characterizing crosslinked polymers are presented, and mathematical analyses are given to calculate the degree of swelling, molecular weight between crosslinks, and other characteristics of neutral and ionic polymers based upon such values as the polymer/solvent interaction parameter, dissociation constant of the pendant chains within the polymer and number average molecular weight before crosslinking.
Abstract: SUMMARY In preparing and evaluating polymers for use as absorbent materials, it is critical to know those parameters which will govern the nature of the final polymer. This chapter presents different methods of producing and characterizing crosslinked polymers. Mathematical analyses are given to calculate the degree of swelling, molecular weight between crosslinks, and other characteristics of neutral and ionic polymers based upon such values as the polymer/solvent interaction parameter, dissociation constant of the pendant chains within the polymer and number average molecular weight before crosslinking. Typical values of these parameters and appropriate references are given for some of the more common polymers such as poly(2-hydroxyethyl methacrylate) and Polyacrylamide.

Journal ArticleDOI
TL;DR: This article will attempt to answer three questions that are central to adenosine research that are also relevant to the extracellular actions of ATP, and in fact analogous questions can be framed for ATP.
Abstract: Adenosine is the final product of the stepwise dephosphorylation of ATP. Like ATP, adenosine has numerous pharmacodynamic actions mediated by cell surface receptors. Because of its close structural and metabolic relationship to ATP, adenosine has a role that is closely intertwined with the roles of intracellular and extracellular ATP. This article will attempt to answer three questions that are central to adenosine research. These questions are also relevant to the extracellular actions of ATP, and in fact analogous questions can be framed for ATP. Because the field of extracellular ATP research is still relatively young, clear answers to most of these questions are not yet available for ATP, and in fact these questions may form an agenda for ATP research in the 1990s.

Journal Article
TL;DR: The results demonstrate that the immunosuppressive effects observed after morphine pellet implantation are naltrexone reversible and suggest that activation of the adrenal is one potential mechanism for this effect.
Abstract: Chronic morphine treatment elicits a variety of immunosuppressive effects in mice. Most of the work describing this immuno-suppressive activity of the opioid is based on in vitro assessments of the performance of certain components of the immune system in morphine-treated animals. Relatively little has been done by way of tracking the effects of chronic morphine treatment on immunologic parameters in the intact animal. Therefore, this study used several classic in vivo determinations of immune function in mice treated chronically with morphine. Morphine pellet (75 mg) implantation led to a significant inhibition (91%) of paw swelling in a picryl chloride-induced delayed type hypersensitivity response. Uptake of iododeoxyuridine in an in vivo lymphocyte proliferation assay and splenomegaly in a graft vs. host reaction were also significantly suppressed by morphine pellet implantation (34 and 52%, respectively). Coimplantation of a naltrexone pellet (10 mg) completely reversed the suppressive responses to morphine in each assay. Naltrexone alone had no significant effect in any of the assays. The suppressive effects of morphine were less pronounced in adrenalectomized mice in the graft vs. host assay (51% vs. 9% reduction in morphine-pelleted shams relative to morphine-pelleted adrenalectomized mice). These findings indicate the pathophysiologic significance of the previously reported suppression of in vitro correlates of immune function in morphine-pelleted mice. The results further demonstrate that the immunosuppressive effects observed after morphine pellet implantation are naltrexone reversible and suggest that activation of the adrenal is one potential mechanism for this effect.

Journal ArticleDOI
TL;DR: Cloned cDNAs encoding a 35-kilodalton cysteine protease that is a major component of protective extracts isolated from blood-feeding Haemonchus contortus adult worms and displays an overall 42% sequence identity with the human lysosomal thiol protease cathepsin B.

Journal ArticleDOI
TL;DR: Results suggest that a stable local structure is formed at the CA junction, which influences insulin-specific packing interactions, and it is proposed that this structure (designated the "CA knuckle") provides a recognition element for type II proinsulin endopeptidase.
Abstract: The proinsulin-insulin system provides a general model for the proteolytic processing of polypeptide hormones. Two proinsulin-specific endopeptidases have been defined, a type I activity that cleaves the B-chain/C-peptide junction (Arg{sup 31}-Arg{sup 32}) and a type II activity that cleaves the C-peptide/A-chain junction (Lys{sup 64}-Arg{sup 65}). These endopeptidases are specific for their respective dibasic target sites; not all such dibasic sites are cleaved, however, and studies of mutant proinsulins have demonstrated that additional sequence or structural features are involved in determining substrate specificity. To define structural elements required for endopeptidase recognition, the authors have undertaken comparative {sup 1}H NMR and photochemical dynamic nuclear polarization (photo-CIDNP) studies of human proinsulin, insulin, and split proinsulin analogues as models or prohormone processing intermediates. The overall conformation of proinsulin is observed to be similar to that of insulin, and the connecting peptide is largely unstructured. In the {sup 1}H NMR spectrum of proinsulin significant variation is observed in the line widths of insulin-specific amide resonances, reflecting exchange among conformational substrates; similar exchange is observed in insulin and is not damped by the connecting peptide. The aromatic {sup 1}H NMR resonances of proinsulin are assigned by analogy to the spectrum of insulin, and assignments are verifiedmore » by chemical modification. These results suggest that a stable local structure is formed at the CA junction, which influences insulin-specific packing interactions. They propose that this structure (designated the CA knuckle) provides a recognition element for type II proinsulin endopeptidase.« less

Journal ArticleDOI
TL;DR: The serum corticosterone concentration in rats was increased by injection of quipazine, a relatively nonselective serotonin agonist, or 8-hydroxy-2-(di-n- propylamino)tetralin (8-OH-DPAT), a serotonin agonists selective for the 5-HT1A subtype of receptor.
Abstract: The serum corticosterone concentration in rats was increased by injection of quipazine, a relatively nonselective serotonin (5-hydroxytryptamine; 5-HT) agonist, or 8-hydroxy-2-(di-n-propylamino)tetral

Journal ArticleDOI
TL;DR: In this article, the synthesis of LY248686 (1), a potent inhibitor of serotonin (5HT) and norepinephrine (NE) uptake has been established by single crystal x-ray analysis.

Journal Article
TL;DR: Data pooled from two large, fixed-dose trials support the efficacy of a fixed 20 mg/day dose of fluoxetine in the treatment of depression and suggest a dose relationship for adverse events during fluoxettine therapy.
Abstract: Data from two large, fixed-dose trials support the efficacy of a fixed 20 mg/day dose of fluoxetine in the treatment of depression. Data pooled from these two studies suggest a dose relationship for adverse events during fluoxetine therapy. At a fixed 20 mg/day dose, only nausea and insomnia were reported by a significantly greater percentage of patients (p less than .05) than those treated with placebo. However, at 60 mg/day, nausea, anxiety, dizziness, and insomnia were reported by a significantly greater percentage of patients (p less than .05) than those treated with placebo. The potential relationship of response rate [Hamilton Rating Scale for Depression (HAM-D) total decrease greater than or equal to 50%] to plasma concentrations of fluoxetine, norfluoxetine, and fluoxetine plus norfluoxetine was evaluated in one study which excluded early responders (less than or equal to 3 weeks of therapy). No significant relationship was found. Furthermore, adverse events were not related to plasma concentrations.