The use of OCT in good visual acuity MOGAD and AQP4-NMOSD patients; with and without optic neuritis.

Myelin oligodendrocyte-antibody-associated disease (MOGAD) often presents with severe optic neuritis (ON) but tends to recover better than in aquaporin-4 antibody neuromyelitis optica spectrum disorder (AQP4-NMOSD). We measured OCT and VEP in MOGAD and AQP4-NMOSD eyes with good visual function, with or without previous ON episodes. Surprisingly, OCT and/or VEPs were abnormal in 84% MOGAD-ON versus 38% AQP4-NMOSD-ON eyes (p = 0.009) with good vision, compared with 18% and 17% respectively of eyes with no previous ON. A sub-group with macular OCT performed as part of a research study confirmed both retinal and macular defects in visually-recovered MOGAD eyes. These findings have implications for investigation and management of MOGAD patients.

Effect of ferrous ion concentration on the kinetics of radiation-induced iron-oxide nanoparticle formation and growth.

Magnetite nanoparticles were formed by γ-radiolysis of solutions containing different initial concentrations of FeSO4 without any other chemical additives. The particles formed in a given [Fe2+]0 had a narrow size distribution and the average size increased with [Fe2+]0. Five hour irradiation at 0.8 Gy s-1 produced an average size ranging from 23 ± 2 nm to 300 ± 40 nm in 0.1 mM or 10 mM [Fe2+]0 solutions, respectively. To ascertain the size-determining mechanism, the kinetics of γ-radiation-induced particle formation and growth were investigated by simultaneously analyzing the [H2(g)] in the headspace, the [FeII] and [FeIII] dispersed in solution, UV-Vis absorbances at 304 nm and 380 nm, and the pH of the solution. The particles formed were characterized by TEM imaging and various spectroscopic analyses. For a given [Fe2+]0 the time-dependent behaviours of different analyses collectively show three distinct kinetic stages of iron oxidation. The [Fe2+]0 affects the oxidation kinetics of different stages and hence, the oxidation yields and the size of particles formed after irradiation. The main processes which cause the observed kinetics and yields in the three stages are proposed.

Characterization of neuropilin-1 structural features that confer binding to semaphorin 3A and vascular endothelial growth factor 165.

Neuropilin-1 (Npn-1) is a receptor for both semaphorin 3A (Sema3A) and vascular endothelial growth factor 165 (VEGF(165)). To understand the role Npn-1 plays as a receptor for these structurally and functionally unrelated ligands, we set out to identify structural features of Npn-1 that confer binding to Sema3A or VEGF(165). We constructed Npn-1 variants containing deletions within the "a" and "b" domains of Npn-1. More than 16 variants were expressed in COS-1 cells and tested for alkaline phosphatase-Sema3A as well as alkaline phosphatase-VEGF(165) binding. Our results indicate that each of the two Npn-1 CUB domains and the amino-terminal coagulation factor V/VIII domain (CF V/VIII) are essential for Sema3A binding, but only the amino-terminal Npn-1 CF V/VIII domain is required for binding to VEGF(165). Guided by the structure of the bovine spermadhesin CUB domain, point mutants targeting defined surfaces of the Npn-1 a1 CUB domain were generated and tested for Sema3A and VEGF(165) binding. One Npn-1 variant, Npn-1(2ABC), exhibits complete loss of Sema3A binding while retaining normal VEGF(165) binding. Moreover, co-immunoprecipitation experiments show that Npn-1(2ABC) can form a signaling complex with the VEGF(165) signaling receptor KDR/VEGFR-2. These results establish the identity of contact sites between Npn-1 and its semaphorin ligands, and they provide a foundation for understanding how Npn-1 functions as a receptor for distinct classes of ligands in vivo.

Vascular endothelial growth factor isoforms display distinct activities in promoting tumor angiogenesis at different anatomic sites.

The gene for the major angiogenic factor, vascular endothelial growth factor (VEGF), encodes several spliced isoforms. We reported previously that overexpression of two VEGF isoforms, VEGF(121) and VEGF(165), by human glioma U87 MG cells induced tumor-associated intracerebral hemorrhage, whereas expression of a third form, VEGF(189), did not cause vessel rupture. Here, we test whether these VEGF isoforms have distinct activities for enhancing vascularization and growth of gliomas in mice. U87 MG cells that overexpressed VEGF(165) or VEGF(189) grew more rapidly than the parental cells in both s.c. and intracranial (i.c.) locations. However, cells that overexpressed VEGF(121) only showed enhancement of i.c. tumor growth but had a minimal effect on s.c. glioma progression. At both anatomical sties, VEGF(165) and VEGF(189) strongly augmented neovascularization, whereas VEGF(121) only increased vessel density in brain tumors. In each type of glioma, expression of VEGF receptors -1 and -2 largely phenocopied the tumor vasculature, because increased VEGF/VEGF receptor-activated microvessel densities were strongly correlated with the angiogenicity and tumorigenicity elicited by the VEGF isoforms at both anatomical sites. One notable difference between the sites was the expression of vitronectin, a prototypic ligand of alpha(v)beta(3) and alpha(v)beta(5) integrins, detected in i.c. but not in s.c., gliomas. Endothelial cell migration stimulated by VEGF(121) was potentiated by vitronectin to a greater extent than that stimulated by VEGF(165). This data demonstrates that VEGF isoforms have distinct activities at different anatomical sites and suggest that the microenvironment of different tissues affects the function of VEGF isoforms.

Vascular endothelial growth factor receptor-2 and neuropilin-1 form a receptor complex that is responsible for the differential signaling potency of VEGF(165) and VEGF(121).

The two most abundant secreted isoforms of vascular endothelial growth factor A (VEGF(165) and VEGF(121)) are formed as a result of differential splicing of the VEGF-A gene. VEGF(165) and VEGF(121) share similar affinities at the isolated VEGF receptor (VEGFR)-2 but have been previously demonstrated to have differential ability to activate VEGFR-2-mediated effects on endothelial cells. Herein we investigate whether the recently described VEGF(165) isoform-specific receptor neuropilin-1 (Npn-1) is responsible for the difference in potency observed for these ligands. We demonstrate that although VEGFR-2 and Npn-1 form a complex, this complex does not result in an increase in VEGF(165) binding affinity. Therefore, the differential activity of VEGF(165) and VEGF(121) cannot be explained by a differential binding affinity for the complex. Using an antagonist that competes for VEGF(165) binding at the VEGFR-2.Npn-1 complex, we observe specific antagonism of VEGF(165)-meditated phosphorylation of VEGFR-2 without affecting the VEGF(121) response. These data indicate that the formation of the complex is responsible for the increased potency of VEGF(165) versus VEGF(121). Taken together, these data suggest a receptor-clustering role for Npn-1, as opposed to Npn-1 behaving as an affinity-converting subunit.

Calcitonin gene-related peptide promotes transient radiocalcium uptake into chick bone in vivo.

We have examined the in vivo effects in chicks of intravenously injected chicken (c-) and rat (r-) calcitonin gene-related peptides (CGRP) on uptake into bone of a simultaneously administered 45Ca label. Both peptides caused transient (10 min) increases in 45Ca uptake into a variety of bone types. In dose-response experiments at 10 min, CGRP doses of 0.26-1.04 nmol/100 g body wt were found to give maximal responses. These were well developed in chicks fasted for 22 h but absent in those which were continuously fed. This contrasts with the hypercalcaemic effect of CGRP which is apparent in fed rather than fasted chicks.

Effects of rat and chicken calcitonin gene-related peptides (CGRP) upon calcium metabolism in chicks.

In vivo effects of intravenously injected chicken(c-) and rat(r-) calcitonin gene related peptide (CGRP) upon plasma total (Cat), ionized (Cai) calcium, inorganic phosphate (Pi) and clearance of an acutely administered 45Ca label have been examined in chicks. Both peptides were hypercalcaemic in fasted chicks, unlike previously reported hypocalcaemic response in mammals. r-CGRP was hypercalcaemic at doses of both 0.26 and 1.31 nmol/100 g body wt, the lower dose produced a significant elevation of Cat one hour after injection into 12-h-fasted chicks, the upper dose had a similar effect at 20 min. Cai was also non-significantly elevated by r-CGRP. Pi was slightly increased by r-CGRP at both doses, 20 and 60 min after injection. c-CGRP produced a dose (0.26-4.17 nmol/100 g body wt) dependent elevation of Cat and Cai in 22-h-fasted chicks. A greater response was however seen in fed animals. Peak responses were observed 45 min after injection. c-CGRP (1.04 nmol/100 g body wt) caused a significant decline in plasma Pi (P less than 0.05) in fasted chicks. Pi was elevated in control fed animals compared with fasted controls. c-CGRP (1.04 nmol/100 g) did not effect plasma Pi in fed chicks. Whilst both peptides elevated plasma Ca, clearance of an acutely administered 45Ca label from plasma was greater in both r-CGRP treated 12-h-fasted chicks and c-CGRP treated 22-h-fasted chicks. In contrast, the rate of 45Ca clearance in fed chicks was not affected by c-CGRP treatment. The differential effects of these peptides upon plasma 45Ca clearance and other plasma parameters of Ca metabolism, suggest a complex mode of action of the peptide upon avian Ca homeostasis, possibly involving direct actions upon kidney and bone.

Disposition of the aromatase inhibitor LY56110 and associated induction and inhibition studies in rats, dogs, and monkeys.

Compound LY56110 was well absorbed but slowly excreted in the rat, dog, and monkey. Oral administration of 5 mg/kg of [14C]LY56110 (5-bis(4-chlorophenyl)methylpyrimidine) to the rat, monkey, and dog resulted in a total excretion of 68, 65, and 30% of the radioactivity within 5 days, respectively. Very low urinary excretion was observed in the rat and dog (2%), with fecal excretion being the predominant mode of elimination in all three species. The plasma radioactivity half-life was 49, 41, and greater than 100 hr in the rat, monkey, and dog, respectively. The plasma half-life of parent compound was 18 hr in the rat and 10 hr in the dog. LY56110 accounted for only 25, 12, and 1% of the plasma radioactivity area under the curve in the rat, dog, and monkey, respectively. High levels of radioactivity were observed in the target tissues of fat, adrenals, and ovaries of rats. LY56110 induced hepatic cytochromes b5 and P-450 and cytochrome c reductase in rats after 14 days of oral dosing at 10 mg/kg but not in monkeys after 10 days of oral dosing at 10 mg/kg. The compound was more potent than aminoglutethimide or cimetidine in inhibiting hepatic ethylmorphine and p-nitroanisole demethylase activity in vitro. LY56110 also inhibited ethinamate-induced sleeping time in rats in vivo. The compound induced a reverse type I binding spectrum with rat ovarian microsomes.

Inhibition of microsomal biotransformation by a series of nitrogen and oxygen heterocyclic histamine H2-antagonists.

A homologous series of potent, long-lasting thiazolo-pyrimidone-pyridine histamine H2-antagonists were examined for their inhibitory effects on rat hepatic ethylmorphine N-demethylation. Inhibitory potency increased in the order: 2-pyridinyl less than 3-pyridinyl less than 4-pyridinyl histamine H2-antagonist. Substitution ortho to the pyridine nitrogen decreased inhibitory potency. Hydroxylation of the pyridine heterocycle decreased inhibitory potency, whereas substituent electronic effects did not appreciably alter the inhibitory potency of these compounds. Antagonists containing oxygen heterocycles were moderately potent inhibitors compared to those containing unsubstituted pyridine as the heterocycle. A 3-(6-methylpyridine) histamine H2-antagonist was shown to be a slightly more potent inhibitor of ethinamate metabolism than cimetidine in rats. However, unlike cimetidine, it did not inhibit the plasma half-life of antipyrine in dogs at doses that were equally efficacious in inhibiting gastric acid secretion.

Dentine is biochemically abnormal in osteogenesis imperfecta.

In osteogenesis imperfecta the bones are brittle but the teeth, whose dentine contains the same genetic collagen as bone (type I), may be clinically normal. To investigate this paradox we have measured the amino acid composition of insoluble dentine collagen from 16 deciduous and 18 permanent teeth in control subjects and in 59 patients with different forms of osteogenesis imperfecta. In 55 of the patient samples significant differences from normal were found, especially in the number of lysine residues, and in the relative amounts of hydroxylysine to lysine. These results demonstrate the high frequency of biochemical abnormalities in osteogenesis imperfecta. They also suggest that classifications of this disorder based on the presence or absence of clinical dentiogenesis imperfecta are likely to be unsound.

Tularemia: emergency department presentation of an infrequently recognized disease.

Tularemia is an uncommon, highly communicable disease occurring with seasonal regularity in endemic parts of the United States. The varied signs and symptoms may confound the unwary physician. Two cases are reported illustrating the ulceroglandular and ingestion forms of the disease. Septic (typhoidal), oculoglandular, pleuropulmonary, glandular, and oropharyngeal forms also are described. Knowledge of the epidemiology and a high index of suspicion should lead the examining physician to ask revealing questions. The diagnosis is presumed upon clinical grounds and confirmed by serological testing. According to published reports delayed diagnosis can result in an overall mortality rate of 7% of cases; however, early diagnosis will lead to uncomplicated recovery in most cases.

The pharmacokinetics of indecainide in mice, rats, dogs, and monkeys.

The pharmacokinetics of indecainide, a new antiarrhythmic agent, were studied in mice, rats, dogs, and monkeys. The drug was well absorbed in all species tested resulting in peak plasma levels of drug within 2 hr. The plasma half-life of indecainide after acute oral administration was 3-5 hr in rats, dogs, and monkeys but considerably shorter in mice. The plasma half-life of indecainide was dose-dependent in dogs and increased slightly with chronic dosing. Peak plasma levels of drug were also dose-dependent in dogs and monkeys. Fecal elimination was the primary route of excretion of the drug in rats and mice after oral dosing. Fifty per cent of the dose was excreted in the bile of rats which was then subject to enterohepatic circulation. Urinary elimination was the predominant excretory route in the dog. Tissue distribution of radioactivity in rats showed that tissues which first encounter the drug have the highest levels of radioactivity. The highest concentrations were found in the stomach, intestine, liver, and kidney, whereas very low levels were observed in the fat and brain. Except for liver and kidney, only very low levels were present after 24 hr.

Metabolism of the antiarrhythmic agent, indecainide, in rats, dogs, and monkeys.

The biotransformation of indecainide, a potent new antiarrhythmic agent, has been studied in rats and dogs. Indecainide was excreted in the urine primarily as the unchanged compound. The major urinary metabolite was desisopropyl indecainide which accounted for approximately 5% of the urinary radioactivity in both species. This metabolite was also detected in the plasma of rats, dogs, and monkeys. Peak plasma levels of the amine metabolite were 15 and 19% of the peak plasma levels of indecainide in rats and dogs, respectively. Loss of isopropylamine resulted in the formation of an aldehyde intermediate which was stabilized as the cyclic acylaminocarbinol. An acidic metabolite presumably derived from oxidation of the aldehyde was detected as well as a cyclic imide metabolite. An additional minor metabolite corresponding to N-formyl indecainide was observed in the urine but the mechanism of its formation is unknown.

Disposition and metabolism of a new benzothiophene antiestrogen in rats, dogs and monkeys.

A new benzothiophene-derived antiestrogen (LY156758) when orally administered was well absorbed in rats and monkeys while approx. 20% was absorbed in dogs. In the rat the compound was subject to first-pass hepatic metabolism which led to low levels of parent drug in the systematic circulation together with a small amount as the glucuronide conjugate. In monkeys the compound occurred primarily as the glucuronide conjugate of parent drug with very little circulating free drug. The systemic bioavailability of free parent drug in plasma was 39% in rats, 17% in dogs and 5% in monkeys. Excretion of the drug in rats and dogs was primarily via the bile. Approx. 1% of the dose was excreted in the urine of rats and dogs after oral dosing. In rats, at least 50% of an oral dose was excreted in bile as the glucuronide conjugate of parent drug.

Saturation of an alpha, beta-unsaturated ketone: a novel xenobiotic biotransformation in mammals.

Reduction of an alpha, beta-unsaturated ketone to the corresponding saturated ketone in a 2-benzylidene-3-ketocoumaran derivative has been investigated. Reductase activity resides in the cytosolic fraction of liver, lung and kidney. Rat and human blood also contain significant reductase activity. Hepatic reductase activity was high in guinea-pigs followed by hamsters, rabbits, rats and mice. The substrate had an apparent Km and Vmax of 5.6 microM and 1.3 nmol/min per mg protein, respectively. The reduction was dependent upon NADPH having an apparent Km of 14.8 microM and a Vmax of 1.0 nmol/min per mg protein. Only the A side hydrogen of NADPH was incorporated into the reduced product. The reaction was inhibited by cyanide, and sulphydryl reagents. Phenobarbital did not induce the activity in rats.

Consensus guidelines for product sterilization.

Sterilization requires a thorough understanding of both technical and regulatory requirements. The development of consensus guidelines has proven to be an effective method of establishing sterilization practices that can meet both regulatory and technical requirements. Regulatory rules prepared without industry participation have proven to be more costly and less effective than consensus guidelines. The AAMI recommended practice, Guideline for Industrial Ethylene Oxide Sterilization of Medical Devices, exemplifies the value of the consensus approach.

Alpha, beta-ketoalkene reduction. A novel reduction pathway in mammalian tissues.

Reduction of an alpha, beta-unsaturated ketone to the corresponding saturated ketone in a 2-benzylidene-3-ketocoumaran derivative has been characterized with respect to subcellular and tissue distribution, species specificity, cofactor requirements, kinetic constants, and effects of inhibitors. In rats, the highest activity was found in the hepatic cytosolic (100,000g supernatant) fraction having an apparent substrate Km and Vmax of 5.6 microM and 1.3 nmol/min/mg protein, respectively. In rat hepatic cytosolic incubations, NADPH supported the reduction reaction having an apparent Km of 15 microM while NADH was 70% less effective in catalyzing the reaction than NADPH. The most effective inhibitors of the reaction were potassium cyanide and sulfhydryl reagents such as p-chloromercuribenzoic acid and iodoacetamide. Glutathione, dithiothreitol, and flavin mononucleotide were without consequential effect. Phenobarbital did not induce the activity in rats. Guinea pig hepatic cytosol was approximately 8 times more active than rat hepatic cytosol in catalyzing the reduction reaction. In rats, whole blood catalyzed the reduction of the substrate in the absence of added NADPH. Hemolysis resulted in a loss of activity which could be restored by addition of NADPH. Cinnamic acid was not reduced by the rat cytosolic fraction. The enzyme utilizes the A-side hydrogen atom at C-4 of NADPH.