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PubMed1985

Mapping and ultrastructure of serotonin-immunoreactive neurons in the optic lobes of three insect species.

With antibodies to serotonin (5-HT) we have mapped immunoreactive neurons in the optic lobes of three species, the blowfly Calliphora, the desert ant Cataglyphis, and the worker bee Apis. The main emphasis in this investigation is on a system of 5-HT-positive neurons connecting the most peripheral neuropil of the optic lobes, the lamina, to more central neuropil regions. To aid in electron microscopical identification of these neurons we used immunocytochemistry at the EM-level and Golgi-EM for Calliphora and horseradish peroxidase (HRP) labelling for the other two insects. The immunoreactive terminals in Calliphora and the HRP-labelled ones in the other insects contain large (c. 100 nm) granular vesicles and smaller (c.60 nm) clear vesicles. In Cataglyphis and Apis the profiles with granular vesicles are presynaptic to second order neurons of the lamina, whereas in Calliphora no synaptic contacts were found. In this animal the 5-HT-positive terminals are situated distal to the synaptic layer of the lamina, in a region of retinal photoreceptor axons and perikarya of the lamina monopolar neurons. In Catagylphis and Apis the interactions of the 5-HT-neurons with the laminar neurons might occur through chemical synapses, whereas in Calliphora neuroactive substance could be released non-synaptically from varicosities distal to the synaptic layer. The possible involvement of 5-HT in control of neuronal activity in the optic lobes is discussed.

Animals↗
PubMed1995

Yeast aminopeptidase I is post-translationally sorted from the cytosol to the vacuole by a mechanism mediated by its bipartite N-terminal extension.

Transport of aminopeptidase I (API) to the vacuole appears to be insensitive to blockage of the secretory pathway. Here we show that the N-terminal extension of the 61 kDa precursor of API (pAPI) is proteolytically processed in two sequential steps. The first step involves proteinase A (PrA) and produces a 55 kDa unstable intermediate (iAPI). The second step involves proteinase B (PrB) and converts iAPI into the 50 kDa stable, mature enzyme (mAPI). Reversion of the cup1 growth phenotype by a pAPI-CUP1 chimera indicates that pAPI is transported to the vacuole by a post-translational mechanism. Deletion of the first 16 amino acids results in accumulation of the truncated protein in the cytosol, indicating that pAPI is actively transported to the vacuole. The chimera pAPI-myc, constructed by fusing a myc tag to the C-terminus of pAPI, was exploited to dissect the mechanism of pAPI transport. Cell fractionation studies show the presence of iAPI-myc and mAPI in a fraction of vacuoles purified by density centrifugation. This and the sequential conversion of pAPI-myc into iAPI-myc and mAPI lacking the myc tag is consistent with insertion of pAPI into the vacuolar membrane through its N-terminal extension. The specific mechanism of API sorting demonstrates a new pathway of protein transport in vacuolar biogenesis.

Amino Acid Sequence↗
PubMed2004

Measurement of low-dose active pharmaceutical ingredient in a pharmaceutical blend using frequency-domain photon migration.

Frequency-domain photon migration (FDPM) measurements of time-dependent light propagation are conducted to provide the powder absorbance for quantitative prediction of terazosin as the active pharmaceutical ingredient (API) in a low-dose (0.72 wt %) oral tablet formulation. Calibration of the FDPM-derived powder absorbance at discrete wavelengths of 514, 650, 687, and 785 nm was performed for API contents ranging between 0 and 1.5 wt % in mixtures showing maximum sensitivity at 650 nm. The relative standard deviation (RSD) of FDPM absorption coefficient measurement at 650 nm in a well-mixed 1.08 wt % terazosin blend was <1.6%, of which no more than 0.12% arose from FDPM instrumental error and the remainder was attributable to the complete-random-mixture model. The applicability of FDPM as an on-line sensor for powder-blending operations was further evaluated by analyzing grab samples taken directly from five locations of a 2-cu-ft Gallay blender at intervals of 5 min within the blending process. FDPM results indicate that homogeneity was largely achieved in the first 10 min, during which the RSD of API content across five sampling locations decreased from 27% to 8%, and the RSD decreased to 5% after 25 min of blending. Evolution of homogeneity within the blending process assessed through FDPM measurements was fit to the first-order model of particle blending further evidencing applicability for monitoring powder-blending processes.

Calibration↗
PubMed2005

Determination of polymorph conversion of an active pharmaceutical ingredient in wet granulation using NIR calibration models generated from the premix blends.

Near infrared (NIR) spectroscopy was used for quantitatively monitoring polymorph conversion of an active pharmaceutical ingredient (API) in wet granulation. The API under pharmaceutical development has two different polymorphs. Polymorph A is the stable form for drug development and polymorph B is the undesired form produced at elevated temperature and humidity. Because a reference method was not available for quantitation of polymorph B, a calibration set was not readily available for NIR method development. Analysis of NIR spectra of different polymorphs of the API, the premix blend and wet granulation samples revealed narrow spectral regions, which were unique to polymorph B and insensitive to differences in physical properties between the premix blend and wet granulation. Therefore, the premix blend samples spiked with polymorph B were used as the calibration set. The final univariate NIR method can be used for off-line or on-line monitoring of polymorph conversion in the wet granulation process.

Calibration↗
PubMed2006

A process analytical technology approach based on near infrared spectroscopy: tablet hardness, content uniformity, and dissolution test measurements of intact tablets.

Near infrared spectroscopy (NIRS) is a nondestructive analytical technique that enables simultaneous measurements of chemical composition (viz. the content in active pharmaceutical ingredient, API) and various physical properties (viz. tablet hardness and dissolution profile) in pharmaceutical tablets. In this work, partial least squares (PLS) calibration models and discriminant partial least squares (DPLS) classification models were constructed by using calibration sets consisting of laboratory samples alone. The laboratory samples were mixtures of the API and excipients that were pressed into tablets. API content, tablet hardness, and dissolution measurements of intact tablets were made by using three different calibration models that are fast--results can be obtained within a few seconds--, simple and robust--they involve minimal analyst intervention--, and clean--they use no toxic reagent and produce no toxic waste. Based on the results, the proposed NIR method is an effective alternative to current reference methods for the intended purpose. The advantages provided by NIR spectroscopy in this context confirm its potential for inclusion in process analytical technologies in the pharmaceutical industry.

Calibration↗
PubMed2003

Differentiation of isomeric flavone/isoflavone aglycones by MS2 ion trap mass spectrometry and a double neutral loss of CO.

The fragmentation behaviour of seven pairs of isomeric flavone/isoflavone aglycones (solely hydroxylated and/or methoxylated) was studied using ion trap mass spectrometry with atmospheric pressure ionisation (API, both electrospray and APCI) in the positive and negative ion modes. A major difference was found in the neutral loss of 56 u, which was a common feature of all isoflavones in API(+). It was identified as a double loss of CO by accurate mass tandem mass spectrometric (MS/MS) measurements using a hybrid quadrupole time-of-flight (Q-TOF) instrument. Fragmentation of daidzein with (13)C-isotope labelling of the carbon C2 showed that this double loss occurred from the central ring of the molecule. A mechanism for this selective fragmentation is given. Further isoflavone-specific fragmentations were used to develop a guideline for the identification of isoflavone structures. A software-based neutral loss scan of 56 u in the API(+)-MS(2) mode was applied to extracts of leaves of Lupinus albus and to soy flour. The structure elucidation guideline allowed identification of hydroxy and/or methoxy isoflavones. Structures could be confirmed for those available as reference compounds.

Carbon Monoxide↗
PubMed2006

Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry.

The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion scans on most abundant background ions to draw a family tree of the commonly occurring chemical background ions. The possible structures and the origins of the major chemical background noise are clearly revealed in the family trees. In agreement with some suggestions in the literature, the chemical background ions studied so far can be classified mainly as either ions of contaminants (or their degradation fragments) or cluster-related ones. A significant contribution from the contaminants (airborne, from tubing and/or solvents) from plasticizer additives (phthalates, phenyl phosphates, sebacates and adipates, etc.) and silicones is concluded. These ions of contaminants can also serve as nuclei for the clustering of HPLC solvent or additives, such as water and acetic acid, thereby leading to a second family of background ions. This study explains the persistence of some chemical background noise even under fairly strong declustering conditions in API LC/MS. One of the other interesting conclusions is that there is a clear difference in structures between the chemical background ions and the protonated analytes generated under atmospheric pressure ionization. This conclusion will contribute to the on-going research efforts to exclusively remove or reduce the interference of chemical background noise in API LC/MS.

Journal Article↗
PubMed1995

The Apyrase gene of the vector mosquito, Aedes aegypti, is expressed specifically in the adult female salivary glands.

The yellow fever mosquito, Aedes aegypti, expresses a gene, Apyrase (Apy), that encodes an ATP-diphosphohydrolase. The product of this gene is a secreted enzyme that facilitates hematophagy by preventing platelet aggregation in the host. Apy gene expression is limited to the cells of the distal-lateral and medial lobes of the adult female salivary glands. Apyrase protein levels, detectable by antibodies, peak in the salivary glands about 4 days after adult emergence and remain high after a blood meal. Primary sequence analysis of a genomic clone encoding apyrase reveals a unique TAAATA sequence and seven introns, as well as other conserved features of eukaryotic genes. The temporal, sex- and tissue-specific expression of the Apy gene is consistent with its role as encoding a platelet anti-aggregation factor that functions to facilitate hematophagy and decrease probing time.

Aedes↗
PubMed1993

An immunohistochemical study of enteropancreatic endocrine cells in larvae and juveniles of the southern-hemisphere lampreys Geotria australis and Mordacia mordax.

The cell types within the endocrine pancreatic tissue and anterior intestine of larvae and juveniles of representatives of the two southern-hemisphere families (Mordaciidae and Geotriidae) were compared, using immunohistochemistry and antisera against insulin (lamprey, bovine), two somatostatins (SST-14, -34), two PP-family peptides (aPY, NPY), and salmon glucagon and glucagon-like peptide (GLP). Cells of the islets and some anterior intestinal cells in larval Mordacia mordax showed intense immunoreactivity (IR) to the two insulin antisera. In contrast, immunoreactivity to these antisera in the islets of larval Geotria australis was restricted to antibovine insulin and even then the staining was weak. The islet cells did not IR with other antisera, but IR to aPY and NPY antisera was noted in a few intestinal cells of both species and cells in the intestine of G. australis were positively stained with antiSST-14 and/or -34. The single islet organ of adults of both species consisted only of antiinsulin-IR, B cells, and D cells, which were IR with only antiSST-14. Although IR was not seen in islet tissue to antisera against aPY, NPY, glucagon, and GLP, four cell types were identified in the intestinal epithelium in both species based on their IR to these antisera and the two antiSSTs. A fifth cell type IR to the two insulin antisera was recognized in adult M. mordax. The types and IR of endocrine cells in the enteropancreatic system of two southern-hemisphere lamprey families are compared with those of the Petromyzontidae, the single family of holarctic lampreys. Differences are discussed in relation to variations in hormone processing and whether they are a consequence of varied ontogenic and phylogenetic history among the extant Petromyzontiformes.

Animals↗
PubMed1996

Assessing adolescent problems: an overview of the adolescent problems inventory

The Adolescent Problems Inventory (API) and the Problem Inventory for Adolescent Girls (PIAG) are commonly employed in studies of antisocial and delinquent behaviour. This paper offers a review and critique of these inventories. The development and construction of the inventories are detailed, followed by discussion of their psychometric properties. The weight of evidence suggests that the inventories are related to behavioural indices associated with antisocial and delinquent behaviour. More recent studies have considered the factor structure of the API, suggesting several dimensions of social functioning. It is concluded that the API and PIAG are robust instruments that can yield valuable clinical and research data.

Journal Article↗
PubMed1984

Persistently increased intestinal fraction of alkaline phosphatase.

Persistent elevation of the intestinal fraction of the alkaline phosphatase (API) as an isolated finding has to our knowledge not been reported previously. It was found in a boy followed during a period of 5.5 years. The only symptom was transient periodic fatigue observed at home, but not apparent during hospitalization. His blood type was O, RH+, Le (a-, b+) and he was a secretor of H-substance, which may be associated with rising API activity after fat-loading. In this case API was unchanged after fat-loading. Neither intestinal nor liver diseases were found, and no other cause for the elevated phosphatase activity could be demonstrated.

Alkaline Phosphatase↗
PubMed1985

Time-dependent effect of sectioning carotid sinus nerves on the vagally mediated baroreflex.

The purpose of the reported experiments was to examine whether the vagally mediated baroreflex system (V-system) increases its feedback gain with time after sectioning of the carotid sinus nerves (CSN). In 10 dogs anesthetized with Nembutal, we determined the overall open-loop gain (G) of the rapidly acting arterial pressure control system. G was assessed as (delta API/delta APs)-1, where delta API and delta APs represent the immediate and steady-state decreases in arterial pressure at the aortic arch following a fast step-wise reduction in blood volume. delta API, delta APs and GINTACT in the intact condition (30th min before sectioning of the CSN) were -1.8 +/- 0.1 kPa, -0.20 +/- 0.01 kPa and 8.4 +/- 0.3 (mean +/- SE), respectively. The mean values of delta API, delta APs and G after sectioning of the CSN (Gv), first averaged within individual dogs and then averaged for ten dogs, were -2.53 +/- 0.07 kPa, -1.1 +/- 0.05 kPa, and 1.5 +/- 0.1, respectively. Gv did not change with time over about 4 h after sectioning of the CSN. It is concluded that the V-system cannot augment its ability to restore arterial pressure in compensation for the lost function of the carotid sinus baroreflex system over 4 h after sectioning of the CSN in the anesthetized dog.

Animals↗
PubMed1982

Comparison of three methods for identification of Enterobacteriaceae.

This study compares the ability of three commercial overnight methods, API 20E, Minitek and Enteric-Tek, to accurately and completely identify 368 clinically isolated Enterobacteriaceae without supplemental tests. Organisms included Escherichia coli (54 strains), Shigella spp. (7), Edwardsiella tarda (1), Salmonella enteritidis (10), Citrobacter spp. (30), Klebsiella spp. (55), Enterobacter spp. (68), Hafnia alvei (2), Serratia spp. (33), Proteus spp. (64), Morganella morganii (24), Providencia spp. (18), and Yersinia enterocolitica (2). Methods were those of the manufactures without supplemental tests. API 20E correctly identified 93.2% of strains to species and 3.3% to genus level only, with 3.0% as part of a spectrum of identifications, and 0.5% incorrect identifications. Minitek yielded 96.0% correct identifications to species and 0.5% to genus level only, with 2.5% spectrum identifications, and 1.0% incorrect identifications. Enteric-Tek correctly identified 97.0% of strains to species level with 3.0% spectrum identifications. API 20E identification of some Serratia and Citrobacter strains was to genus level only. Problem organisms for Minitek included Enterobacter agglomerans and Serratia marcescens. A comparison of these three commercial methods shows that all three have the ability to identify most clinically isolated Enterobacteriaceae without supplemental tests.

Bacteriological Techniques↗
PubMed1982

Speciation of coagulase-negative staphylococci in the clinical laboratory.

The purpose of this study was to evaluate the efficacy of the API Staph System for the speciation of coagulase-negative staphylococci. Three hundred and seventy-one coagulase-negative clinical isolates were studied; 50% of these could be speciated using the code profiles of the API System. By reference to the Kloos and Schleifer schema, 93% of the isolates could be speciated. The distribution of the various staphylococcal species in clinical specimens was determined. It was concluded that the API Staph System would be a satisfactory method of speciation if the data base could be expanded. Such speciation may at times be helpful in interpreting the significance of coagulase-negative staphylococcal isolates in the clinical laboratory.

Coagulase↗
PubMed1979

Evaluation of a modified dye pour-plate auxanographic method for the rapid identification of clinically significant yeasts. Comparison with two commercial systems.

A modified dye pour-plate auxanographic (DPPA) method for the presumptive identification of medically important yeasts was evaluated, in a comparative study with a conventional procedure, the API 20C clinical yeast system (Analytab Products Inc.), and the Uni-Yeast-Tek (UYT) system. The 174 coded clinical isolates were members of the genera Candida, Cryptococcus, Rhodotorula, Saccharomyces, Torulopsis, and Trichosporon. The identification accuracies with DPPA, API, and UYT were 95%, 93%, and 99% respectively. DPPA and API required more time to inoculate but gave rapid identification profiles. UYT was simple to inoculate and both UYT and DPPA were easy to read. Cost analysis of the three rapid methods demonstrated DPPA to be the most economical making it a feasible alternative for small clinical laboratories as well as large laboratories possessing the facilities to make their own media.

Carbohydrate Metabolism↗
PubMed2000

Comparative evaluation of a commercial system for identification of Candida lusitaniae.

The ability of the API Candida system (bioMérieux, France) to identify Candida lusitaniae isolates was evaluated in comparison to the Auxacolor and ID 32C systems using 52 clinical isolates previously identified on the basis of their morphology and their biochemical reactions in the Auxacolor and ID 32C systems. The API Candida system failed to definitively identify most of the strains tested within 24 h. No beta-maltosidase activity was detected in 28 strains, and supplementary tests were required to discriminate Candida lusitaniae, Candida famata and Candida guilliermondii. The API Candida system is not suitable for identification of Candida lusitaniae. In comparison, the Auxacolor system is easy to use and interpret, allowing rapid identification of this species; however, the ID 32C system is required for identification of atypical strains.

Bacterial Typing Techniques↗
PubMed2007

An integrated approach to a teaching file linked to PACS.

To meet the educational needs of a medical imaging department with a strong teaching commitment, a teaching file that uses digital data supplied by the institutional picture archiving and communications system (PACS) was required. This teaching file had to be easily used by the end users, have a simple submission process, be able to support multiple users, be searchable on all data fields, and implementing the teaching file must not incur any additional software or hardware costs. The teaching file developed to address this problem takes advantage of the database structure and capabilities of several components included in the commercial PACS installed at the hospital. MS Access is used to seamlessly integrate with the digital imaging and communication in medicine (DICOM) database of a normal work station that is part of the PACS. This integration allows relevant patient and study demographics to be copied from images of interest and then to be stored in a separate database as the back-end of the digital teaching file. When images for a particular teaching file case need to be reviewed, they are automatically retrieved and displayed from the main PACS database using an open application programming interface (API) connection defined on the PACS web server. Utilizing this open API connection means the teaching file contains only the relevant demographic information of each teaching file case; no image data is stored locally. The open API connection allows access to imaging data usually not encountered in a teaching file, allowing more comprehensive imaging case files to be developed by the radiologist. Other advantages of this teaching file design are that it does not duplicate image data, it is small allowing simple ongoing backup, and it can be opened with multiple users accessing the database without compromising data access or integrity.

Computer-Assisted Instruction↗
PubMed1994

Structural studies of endopolygalacturonase-resistant fragments of an antiulcer pectin from the roots of Bupleurum falcatum L.

The endo-alpha-(1-->4)-polygalacturonase-resistant fractions (PG-1, PG-2, and PG-3) from an antiulcer pectin (Bupleuran 2IIc), isolated from the roots of Bupleurum falcatum L., were further analysed by lithium degradation. The results indicated that PG-1 contained a small proportion of long, branched arabinosyl chains and a large proportion of short, neutral oligosaccharide chains. GLC-MS analysis showed that, after methylation the short, neutral oligosaccharide fraction consisted of at least 22 kinds of di- to tetra-saccharide alditols, such as Gal-(1-->4)-Rha-ol (a major component), Ara-(1-->4)-Rha-ol, Glc-(1-->4)-Rha-ol, Ara-->Ara-->Ara-ol, and Ara-->Ara-->Ara-->Ara-ol (minor components) in addition to heteroglycosyl alditols. After deesterification, PG-2 and PG-3 were digested with endo-alpha-(1-->4)-polygalacturonase again, and the enzyme-resistant intermediate size fraction (PG-2') was purified. Component sugar analysis indicated that PG-2' contained 2-Me-Fuc, 2-Me-Xyl, apiose (Api), aceric acid (AceA), 3-deoxy-D-lyxo-heptulosaric acid (Dha), and 3-deoxy-D-manno-2-octulosonic acid (Kdo) in addition to Rha, Fuc, Ara, Xyl, Man, Gal, Glc, GalA, and GlcA. Lithium degradation of PG-2' gave mainly a pentosyl-->6-deoxyhexosyl-->6-deoxyhexosyl-->pentitol fragment, with some neutral di- and tri-saccharide alditols, including a pentosyl-->deoxyhexitol. Methylation analysis of these degradation products indicated that they contained terminal Rha, Araf, Fuc, Xyl, and Gal, 4-linked Rha, 3-linked Fuc, 3-linked Ara, and 3'-linked Api. Bupleuran 2IIc was eluted as essentially a single peak on gel filtration on Sepharose CL-6B. The neutral sugar content of the successive fractions increased with increasing molecular weight, but each fraction also contained, in addition to Rha, Ara, and Gal, 2-Me-Fuc, 2-Me-Xyl, and Api.

Animals↗