The binding of tissue prokallikrein to isolated human neutrophils.

We have investigated the binding of human tissue kallikrein and the corresponding proenzyme to isolated human lymphocytes and neutrophils, respectively, by the means of steady-state binding assays. It was demonstrated that only prokallikrein bound to washed neutrophils in a time-dependent, specific and saturable manner, whereas in vitro binding of activated kallikrein to neutrophils or lymphocytes could be excluded. Our data provide strong evidence for the specific interaction of prokallikrein with intact human neutrophils and indicate a neutrophil surface binding site for the tissue kallikrein precursor which could be involved in kallikrein endocytosis and selective prokallikrein-to-kallikrein conversion.

Efficacy of injectable anticholinergic drugs against soman-induced convulsive/subconvulsive activity.

Six FDA approved, injectable compounds [benztropine (BZT); biperiden (BIP); dicyclomine (DCL); l-hyoscyamine (HYO); orphenadrine (ORP); scopolamine (SCP)] were each compared to diazepam (DZ, the standard) in male guinea pigs against ongoing soman-induced convulsive or sub-CV (CV/sub-CV) activity. Three trained graders concurrently assigned CV/sub-CV scores to each animal based on signs of intoxication at various times post-soman. Animals received (im) pyridostigmine (26 micrograms/kg) 30 min before soman (56 micrograms/kg; 2 x LD50), atropine (2 mg/kg) admixed with 2-PAM (25 mg/kg) at one min after soman, and the candidate drug preparation at 5.

Genes involved in Haemophilus influenzae type b capsule expression are frequently amplified.

The genes involved in Haemophilus influenzae type b capsule expression are present as a duplication of an approximately 18-kb DNA segment (the Cap b locus). It has been shown previously that recombination occurs between the two copies of the repeat, resulting in deletion of one copy and loss of capsule expression at frequencies of 0.1%-0.

Low power laser irradiation alters the rate of regeneration of the rat facial nerve.

Low power laser irradiation has been reported to cause biological effects due to the photochemical and/or photophysical action of the radiation. This study determined quantitatively if transcutaneous low power laser irradiation can affect the regeneration of the rat facial nerve. The facial nerve was crushed unilaterally in anesthetized rats and transcutaneously irradiated daily with a laser beam directed at the area of the crush injury.

Planar Rayleigh scattering results in helium-air mixing experiments in a Mach-6 wind tunnel.

Planar Rayleigh scattering measurements with an argon-fluoride excimer laser are performed to investigate helium mixing into air at supersonic speeds. The capability of the Rayleigh scattering technique for flow visualization of a turbulent environment is demonstrated in a large-scale, Mach-6 facility. The detection limit obtained with the present setup indicates that planar, quantitative measurements of density can be made over a large cross-sectional area (5 cm x 10 cm) of the flow field in the absence of clusters.

Microbeam laser-injured neurons increase in vitro astrocytic gap junctional communication as measured by fluorescence recovery after laser photobleaching.

An important aspect of the neuronal-astrocyte relationship is the interaction of reactive astrocytes with injured and/or dying neurons. Few studies have focused on the signaling of astrocytes by injured neurons or on the possibility that neurons can alter astrocytic gap junctional communication. The purpose of this study was to determine whether the presence of injured neurons could alter astrocytic gap junctional coupling by establishing an in vitro method of microbeam laser neuronal injury and coculturing these neurons with astrocytes.

A developmental comparison of the effectiveness of encoding tasks.

In Experiment 1, the free-recall performance of young children, college students, and older adults was examined. Subjects encoded words by simply learning them, by studying them in either base or elaborate sentence frames, or by constructing sentences. Overall recall was better for the college students than for the children or for the older adults, and the college students recalled best in the simple learning condition.

Mutation in the Escherichia coli htpR locus results in stabilization of recombinant expression products that are susceptible to proteolytic degradation.

We compared the expression and degradation of three cloned malarial proteins in a pair of isogeneic strains of Escherichia coli that differed at the htpR locus. The htpR locus encodes an alternate sigma factor necessary for the transcription of heat shock promoters. Plasmodium sequences were cloned from polymerase chain reaction-amplified DNA initiated by oligonucleotide primers that were specific for the gene coding regions to be expressed.

Bovine mitochondrial ribosomes possess a high affinity binding site for guanine nucleotides.

Mammalian mitochondrial ribosomes possess a binding site for guanine nucleotides. GTP binds in unit stoichiometry and with high affinity (Kd = 15.3 +/- 2.

The translation system of mammalian mitochondria.

Oligoribonucleotides and mRNA were used to define properties of the bovine mitoribosomal mRNA binding site. The RNA binding domain on the 28 S subunit spans approx. 80 nucleotides of the template, based on ribosome protection experiments, but the major interaction with the ribosome occurs over a 30 nucleotide stretch.

Response of rat cerebral cortical astrocytes to freeze- or cobalt-induced injury: an immunocytochemical and gap-FRAP study.

Astrocytic response in the immediate vicinity of freeze- and cobalt-induced lesions has been examined at the light and ultrastructural level. However, the temporal and spatial distribution of astrocytic reactivity throughout the rat cerebral cortex, using glial fibrillary acidic protein (GFAP) immunolabeling, has not been examined. The first purpose of this study was to establish the chronological distribution of astrocytic reactivity, as measured by changes in GFAP immunoreactivity, following freeze- or cobalt-induced injury to the rat cerebral cortex.

Transection of the rat olfactory nerve increases glial fibrillary acidic protein immunoreactivity from the olfactory bulb to the piriform cortex.

Astrocytic glial fibrillary acidic protein (GFAP) immunoreactivity in response to retrograde changes of motoneurons after axotomy has been the subject of a number of reports. In contrast, this study examined the astrocytic GFAP immunoreactivity in response to axotomy in a sensory system, the adult rat olfactory system. The purpose of this study was to determine, by immunolabeling GFAP, the extent and transience of astrocytic reactivity in the olfactory system.

Transection or electrical stimulation of the hypoglossal nerve increases glial fibrillary acidic protein immunoreactivity in the hypoglossal nucleus.

Glial fibrillary acidic protein (GFAP) immunoreactivity within rat hypoglossal (XIIth) nuclei was examined 1-50 days following either unilateral nerve transection or modest electrical stimulation using indirect immunofluorescence and PAP immunohistochemistry. Both nerve transection and stimulation provoked an increase in the immunodetected GFAP within the XIIth nucleus.

Meningeal cells increase in vitro astrocytic gap junctional communication as measured by fluorescence recovery after laser photobleaching.

The presence of meningeal cells is necessary for the normal development of the glia limitans. Astrocytes comprising the adult glia limitans have several unique features, including many more gap junctions than is typical for astrocytes in the underlying molecular layer. This study examines the possible influence of meningeal cells on the establishment and maintenance of specific characteristics of astrocytes in the glia limitans.

Morphological changes in the junctional complex of cells in the arachnoid layer of the rat after cold injury.

The junctional complexes of cells in the outer arachnoid layer overlying the cerebral cortex of 2-week-old rats were examined with freeze-fracture electron microscopy up to 60 min after transcranial cold injury to the dorsal surface of the brain. Within 30 min after injury, areas of gap and tight junctions with morphological features characteristic of junction formation and/or junction disruption were found scattered among normal junctional complexes in some arachnoid cells. Within 60 min after injury, tight junctions with features typical of less leaky zonulae occludentes were present in all arachnoid cells examined.

Methemoglobin formation resulting from administration of candidate 8-aminoquinoline antiparasitic drugs in the dog.

In vivo methemoglobin (MHb) formation caused by five 8-aminoquinoline compounds was tested in beagle dogs. Male beagle dogs were dosed orally once per day at 0.0116 mmol/kg for 4 consecutive days with primaquine (8-[4-amino-1-methylbutyl)amino]-6-methoxyquinoline, diphosphate), three candidate 8-aminoquinoline antimalarial drugs (WR 225,448 5-(3-trifluoromethyl)phenoxy-4-methyl primaquine, succinate); WR 238,605 2,6-dimethoxy-5-(3-trifluoromethyl)phenoxy-4-methyl primaquine, succinate; or WR 242,511 5-hexoxy-4-methyl primaquine, diphosphate dihydrate), or a candidate 8-aminoquinoline antileishmanial drug WR 6026 (8-[(6-diethylamino)amino]-6-methoxy-4-methyl quinoline, dihydrochloride).

Lactic acid inhibition of gap junctional intercellular communication in in vitro astrocytes as measured by fluorescence recovery after laser photobleaching.

Lactic acid can permeate plasma membranes, causing intracellular acidosis. Gap junctions are sensitive to pHi and can be reversibly uncoupled by weak acids. In this study, dye coupling between in vitro astrocytes, presumably mediated by gap junctions, was measured in the absence and presence of lactic acid.

Analysis of artesunic acid and dihydroqinghaosu in blood by high-performance liquid chromatography with reductive electrochemical detection.

A new high-performance liquid chromatography (HPLC) method using reductive electrochemical detection has been developed for the analysis of the antimalarial drugs artesunic acid (ARTS) and dihydroqinghaosu (DQHS) in blood. Presently, this method has been validated to 4 micrograms/ml for ARTS and 200 ng/ml for DQHS. Pharmacokinetic studies in the rabbit show that after intravenous administration (100 mg/kg) ARTS is metabolized rapidly to DQHS and has a t1/2 of 1.

Phototoxicity from systemic agents.

Phototoxicity caused by systemic agents has been well described in the literature for only a handful of medications. Diagnosis rests initially upon the clinical recognition of a photodistributed eruption. Thereafter, histopathology and light testing with the patient on and off of the suspected medication should confirm the clinical suspicion.

Freeze-fracture studies of plasma membranes of astrocytes in freezing lesions.

Epileptic foci are frequently associated with a proliferation and hypertrophy of fibrous astrocytes. Such proliferating astrocytes, which are involved in scar formation and are referred to as reactive, have been characterized by a number of morphological changes involving the cytoplasmic organelles and nucleus. With the development of freeze-fracture techniques, which allow for the splitting and analysis of the macromolecular structure of biological membranes, another morphological characteristic could be used to define reactive astrocytes.

Structure-activity relationships of putative primaquine metabolites causing methemoglobin formation in canine hemolysates.

A rapid and reproducible in vitro test system was developed to measure the methemoglobin (MHb)-forming properties of various 8-aminoquinoline derivatives. Initial rates and extents of reaction were measured spectrophotometrically with either canine hemolysates from which ferrihemoglobin reductase was removed, or with purified human oxyhemoglobin (Hb). The results demonstrate that primaquine derivatives that can be oxidized to quinones or iminoquinones (5-hydroxy,6-desmethyl primaquine; 5-hydroxyprimaquine; 5,6-dihydroxy-8-aminoquinoline; and 5-hydroxy, 6-methoxy-8-aminoquinoline) are potent MHb-forming compounds.

High-performance liquid chromatographic method for the analysis of a candidate 8-aminoquinoline antileishmanial drug using oxidative electrochemical detection.

An analytical method was developed for the quantitation of a candidate antileishmanial drug, 6-methoxy-8-(6-diethylaminohexylamino)-4-methylquinoline, dihydrochloride, in canine plasma. The assay utilized internal standard technique with a structural similar 8-aminoquinoline, 6-methoxy-8-(7-diethylaminoheptylamino)-4-methylquinoline, dihydrochloride, as the internal standard. The method employs a liquid-solid extraction procedure with prepackaged silica gel columns upon which the drug and internal standard are adsorbed, then selectively washed and eluted.