Isolation of a novel agglutinin with complex carbohydrate binding specificity from fresh fruiting bodies of the edible mushroom Lyophyllum shimeiji

A hemagglutinin, with a molecular weight of 30,000 and expressing hemagglutinating activity which could not be inhibited by simple sugars and glycoproteins, was isolated from fresh fruiting bodies of the edible mushroom Lyophyllum shimeiji. The protein was adsorbed on CM-Sepharose even in 20 mM ammonium acetate (pH 5.5) containing 1 M NaCl and was desorbed by 20 mM ammonium bicarbonate (pH 9). The hemagglutinating activity was subsequently adsorbed on Mono S in 20 mM ammonium acetate (pH 5.5) and was desorbed by a linear gradient of 0.2-0.5 M NaCl in ammonium acetate buffer. The hemagglutinin exhibited a novel N-terminal sequence not found in any lectin and hemagglutinin reported so far. It was devoid of antifungal activity.

Antiproliferative and antimitogenic activities in a peptide from puffball mushroom Calvatia caelata

A peptide with a molecular weight of 8 kDa and an N-terminal sequence closely resembling that of ubiquitin was isolated from fruiting bodies of the mosaic puffball mushroom Calvatia caelata. The peptide was purified using a protocol that involved ion-exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, and ion-exchange chromatography on Mono S. The peptide inhibited translation in the cell-free rabbit reticulocyte lysate system and exhibited N-glycosidase activity. It potently inhibited proliferation of spleen cells with an IC(50) of about 100 nM as indicated by the suppression of [methyl-(3)H]thymidine uptake. The viability of breast cancer cells was reduced to half at a ubiquitin concentration of about 100 nM.

A monomeric mannose-binding lectin from inner shoots of the edible chive (Allium tuberosum)

A mannose-binding lectin was isolated from the inner shoots of the chive Allium tuberosum. The procedure involved aqueous extraction, (NH4)2SO4 precipitation, dialysis to remove (NH4)2SO4, affinity chromatography on mannose-agarose, ion exchange chromatography on SP-Sepharose, gel filtration on Superdex 75, and ion exchange chromatography on Mono S. Lectin activity was adsorbed on mannose-agarose, SP-Sepharose, and Mono S. The lectin demonstrated a molecular weight of 13 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, indicating that it is a single-chain protein. N-terminal sequence analysis revealed its remarkable homology to Allium cepa lectin and similarity to a lesser extent to lectins from members of the Amaryllidaceae, Orchidaceae, and Liliaceae. The lectin manifested mitogenic activity in murine splenocytes and inhibitory activity against human immunodeficiency virus type 1 reverse transcriptase.

Branded versus generic clozapine: bioavailability comparison and interchangeability issues

Clozapine has been the treatment of choice for patients with refractory schizophrenia. Generic clozapine has recently become available, because of a waiver of the usual criteria for establishing bioequivalence. However, there are biopharmaceutical, bioavailability, and clinical concerns related to the generic formulation raised by both clinicians and academic researchers. We conducted a prospective, randomized, crossover study to evaluate steady-state pharmacokinetics, pharmacodynamics, and tolerability of generic clozapine (Zenith Goldline Pharmaceuticals) versus Clozaril (Novartis Pharmaceuticals) in schizophrenic patients. A preliminary report of the pertinent bioavailability results is presented here. Despite comparable mean plasma concentration-time curves, significant differences were found in the primary pharmacokinetic parameters of the 2 formulations in almost 40% of patients. Such intraindividual differences raise the issue of average bioequivalence versus individual bioequivalence and the implication for interchangeability of different clozapine formulations. The decision to switch a patient from branded to generic clozapine should be made on an individual basis with special emphasis on clinical outcome, and patients should be monitored closely during the transition.

A robust cysteine-deficient chitinase-like antifungal protein from inner shoots of the edible chive Allium tuberosum

From the inner shoots of the chive Allium tuberosum, a single-chained protein with a molecular weight of 36 kDa and an N-terminal sequence manifesting resemblance to chitinases but lacking in cysteine residues characteristic of a cysteine-rich domain present in chitinases of other Allium species, was purified. The isolation procedure entailed affinity chromatography on Affi-gel blue gel, ion-exchange chromatography on DEAE-cellulose and Mono S, and gel filtration on Superdex 75. The protein was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel and Mono S. It exhibited antifungal activity against Rhizoctonia solani, Fusarium oxysporum, Coprinus comatus, Mycosphaerella arachidicola, and Botrytis cinerea. The IC(50) for its antifungal effect against Botrytis cinerea was 0.2 microM. The antifungal activity was stable after 1 h at pH 1.6 and 12.3, and up to 60 degrees C for 5 min. Incubation of the protein with trypsin or chymotrypsin at an enzyme:substrate ratio of 1:100 and pH 7.6 up to 150 min did not affect its antifungal activity. The protein did not exhibit antibacterial activity. The protein inhibited cell-free translation in a rabbit reticulocyte system with an IC(50) of 0.8 microM, but did not affect the proliferation of mouse splenocytes. It exerted some cytotoxic effect on breast cancer cells and was inhibitory toward HIV-1 reverse transcriptase.

Surface diffusion coefficients for room acoustics: free-field measures

A surface diffusion coefficient is needed in room acoustics to enable the quality of diffusing surfaces to be evaluated. It may also facilitate more accurate geometric room acoustic models. This paper concentrates on diffusion coefficients derived from free-field polar responses. An extensive set of two- and three-dimensional measurements and predictions was used to test the worth of different diffusion coefficient definitions. The merits and problems associated with these types of coefficients are discussed, and past parameters reviewed. Two new coefficients are described. The new measure based on the autocorrelation function is forwarded as the best free-field coefficient. The strengths and weaknesses of the coefficient are defined.

From a profiled diffuser to an optimized absorber

The quadratic residue diffuser was originally designed for enhanced scattering. Subsequently, however, it has been found that these diffusers can also be designed to produce exceptional absorption. This paper looks into the absorption mechanism of the one-dimensional quadratic residue diffuser. A theory for enhanced absorption is presented. Corresponding experiments have also been done to verify the theory. The usefulness of a resistive layer at the well openings has been verified. A numerical optimization was performed to obtain a better depth sequence. The results clearly show that by arranging the depths of the wells properly in one period, the absorption is considerably better than that of a quadratic residue diffuser.

The adaptive beam-tracing algorithm

The most popular models to predict sound propagation in architectural spaces involve the tracing of rays, images, or beams. Most current beam-tracing methods use conical or triangular beams that may produce overlaps and holes in the predicted sound field. Hence a new method has been developed whereby the shape of reflected beams is governed by the shape of reflecting surfaces so as to produce a geometrically perfect description of the sound propagation for halls with occluding surfaces. The method also facilitates the calculation of diffuse sound propagation by managing the energy transfer from a specular model to a diffuse model. This adaptive beam-tracing method compares well with other methods in terms of speed and accuracy.

Imaging membrane potential with voltage-sensitive dyes

Membrane potential can be measured optically using a variety of molecular probes. These measurements can be useful in studying function at the level of an individual cell, for determining how groups of neurons generate a behavior, and for studying the correlated behavior of populations of neurons. Examples of the three kinds of measurements are presented. The signals obtained from these measurements are generally small. Methodological considerations necessary to optimize the resulting signal-to-noise ratio are discussed.

Photoinduced dehydrogenation of defects in undoped a-si:H using positron annihilation spectroscopy

We report changes in variable-energy positron annihilation spectroscopy measurements on undoped hydrogenated amorphous silicon films after light soaking. The change, seen predominantly in the high momentum band of the annihilation radiation, is not reversed by thermal annealing. We suggest, following recent models of the Staebler-Wronski effect, that light exposure induces hydrogen trapped in vacancylike defects to become mobile in the Si network. The observations place constraints on models of hydrogen motion fitting macroscopic Staebler-Wronski effect kinetics and may help to achieve a definitive description of metastability in a-Si:H.

Odors elicit three different oscillations in the turtle olfactory bulb

We measured the spatiotemporal aspects of the odor-induced population response in the turtle olfactory bulb using a voltage-sensitive dye, RH414, and a 464-element photodiode array. In contrast with previous studies of population activity using local field potential recordings, we distinguished four signals in the response. The one called DC covered almost the entire area of the olfactory bulb; in addition, three oscillations, named rostral, middle, and caudal according to their locations, occurred over broad regions of the bulb. In a typical odor-induced response, the DC signal appeared almost immediately after the start of the stimulus, followed by the middle oscillation, the rostral oscillation, and last, the caudal oscillation. The initial frequencies of the three oscillations were 14.1, 13.0, and 6.6 Hz, respectively. When the rostral and caudal oscillations occurred together, their frequencies differed by a factor of 1.99 +/- 0.01. The following evidence suggests that the four signals are functionally independent: (1) in different animals some signals could be easily detected whereas others were undetectable; (2) the four signals had different latencies and frequencies; (3) the signals occurred in different locations and propagated in different directions; (4) the signals responded differently to changes in odor concentration; (5) the signals had different shapes; and (6) the rostral and caudal signals added in a simple, linear manner in regions where the location of the two signals overlapped. However, the finding that the frequency of the rostral oscillation is precisely two times that of the caudal oscillation suggests a significant relationship between the two. The location of the caudal oscillation in the bulb changed from cycle to cycle, implying that different groups of neurons are active in different cycles. This result is consistent with the earlier findings in the olfactory system of the locust (). Our results suggest an additional complexity of parallel processing of olfactory input by multiple functional population domains.

Clinical pharmacology of dopamine agonists

With the availability of newer dopamine agonists selective for dopamine (D2) receptor subtypes, medical management of Parkinson's disease has progressed substantially. These agents can decrease the frequency of ergot-related side effects and dyskinesias. Also, when given as adjunctive therapy with levodopa, they can allow the levodopa maintenance dosage to be reduced without loss of symptom control. Based on early clinical experience, dopamine agonists can also be prescribed as initial monotherapy and can delay therapy with levodopa. Their therapeutic roles will be defined further by long-term studies.

CYP2D6 inhibition by fluoxetine, paroxetine, sertraline, and venlafaxine in a crossover study: intraindividual variability and plasma concentration correlations

The authors report the CYP2D6 inhibitory effects of fluoxetine, paroxetine, sertraline, and venlafaxine in an open-label, multiple-dose, crossover design. Twelve CYP2D6 extensive metabolizers were phenotyped, using the dextromethorphan/dextrorphan (DM/DX) urinary ratio, before and after administration of fluoxetine 60 mg (loading dose strategy), paroxetine 20 mg, sertraline 100 mg, and venlafaxine 150 mg. Paroxetine, sertraline, and venlafaxine sequences were randomized with 2-week washouts between treatments; fluoxetine was the last antidepressant (AD) administered. Comparing within groups, baseline DM/DX ratios (0.017) were significantly lower than DM/DX ratios after treatment (DM/DXAD) with fluoxetine (0.313, p < 0.0001) and paroxetine (0.601, p < 0.0001) but not for sertraline (0.026, p = 0.066) or venlafaxine (0.023, p = 0.485). Between groups, DM/DXAD ratios were significantly higher for fluoxetine and paroxetine compared to sertraline and venlafaxine. No differences between DM/DXAD ratios were found for fluoxetine and paroxetine although more subjects phenocopied to PM status after receiving the latter (42% vs. 83%; chi 2 = 4.44, p = 0.049, df = 1). Similarly, no differences between DM/DXAD ratios were found for sertraline and venlafaxine. Of note, the DM/DXAD for 1 subject was much lower after treatment with paroxetine (0.058) compared to fluoxetine (0.490), while another subject exhibited a much lower ratio after treatment with fluoxetine (0.095) compared to paroxetine (0.397). Significant correlations between AD plasma concentration and DM/DXAD were found for paroxetine (r2 = 0.404, p = 0.026) and sertraline (r2 = 0.64, p = 0.002) but not fluoxetine or venlafaxine. In addition, DM/DXAD correlated with baseline isoenzyme activity for paroxetine, sertraline, and venlafaxine groups. These results demonstrate the potent, but variable, CYP2D6 inhibition of fluoxetine and paroxetine compared to sertraline and venlafaxine. CYP2D6 inhibition may be related, in part, to dose, plasma concentration, and baseline isoenzyme activity, and these correlations merit further investigation.

CYP2D6 status of extensive metabolizers after multiple-dose fluoxetine, fluvoxamine, paroxetine, or sertraline

The aim of this study was to evaluate the CYP2D6 inhibitory effects of four selective rerotonin re-uptake inhibitors (SSRIs). Thirty-one healthy subjects were phenotyped as extensive metabolizers using the dextromethorphan/dextrorphan (DM/DX) urinary ratio as a marker for CYP2D6 activity before and after 8 days of administration of fluoxetine 60 mg (loading dose strategy), fluvoxamine 100 mg, paroxetine 20 mg, or sertraline 100 mg in a parallel-group design. Statistical analysis was performed on log-transformed DM/DX ratios because of variability within and between treatment groups. DM/DX ratios before (DM/DX(BL)) and after (DM/DX(SSRI)) were compared within and between the four SSRI groups. DM/DX(BL) ratios were not significantly different between the four SSRI treatment groups. Comparing within groups, significant differences between DM/DX(BL) and DM/DX(SSRI) were found for the fluoxetine (p < 0.001; ratio values, 0.020 vs. 0.364) and paroxetine (p = 0.0005, ratio values 0.029 vs. 1.085) but not for the fluvoxamine or sertraline groups. Comparing between groups, significant differences in DM/DX(SSRI) ratios were found for fluoxetine versus sertraline (p = 0.0019, DM/DX = 0.364 vs. 0.057), fluoxetine versus fluvoxamine (p < 0.0001, DM/DX = 0.364 vs. 0.019), paroxetine versus sertraline (p = 0.0026, DM/DX = 1.085 vs. 0.057), and paroxetine versus fluvoxamine (p < 0.0001, DM/DX = 1.085 vs. 0.019). No significant differences were noted between the two potent CYP2D6 inhibitors, fluoxetine and paroxetine, or the two weakest inhibitors, fluvoxamine and sertraline. Five subjects in the fluoxetine and four subjects in the paroxetine groups changed to poor metabolizer phenotype (DM/DX > or = 0.3) after treatment. Although CYP2D6 inhibitory effects of fluvoxamine and sertraline did not yield significant differences from baseline, some subjects exhibited DM/DX ratio increases of 150 to 200%. One paroxetine-treated subject did not exhibit any CYP2D6 inhibition. SSRI dose and plasma concentration may be correlated with the extent of CYP2D6 inhibition and should be further investigated.

Reversible metabolism of clozapine and clozapine N-oxide in schizophrenic patients

1. To characterize the interconversion process between clozapine and its metabolite clozapine N-oxide (CNO), eight healthy male schizophrenics were administered a single dose of clozapine or CNO in a randomized crossover manner. 2. Using a general pharmacokinetic model for the interconversion process, the mean total clearances of clozapine and CNO were 28.45 L/hr and 45.30 L/hr, respectively. These values were similar to the values obtained by the usual model-independent method of pharmacokinetic analysis. 3. When administered clozapine, mean CNO plasma concentrations of 17.7 +/- 16.4 ng/ml were slightly lower than the other clozapine metabolite-desmethylclozapine (DCLOZ) plasma levels of 24.4 +/- 8.6 ng/ml at the 12 hour time point. When CNO was administered, plasma concentrations at the 12 hour time point of clozapine were twice the amount of CNO (28.1 +/- 8.9 ng/ml vs 14.4 +/- 8.8 ng/ml). 4. DCLOZ plasma concentrations were detected in all patients upon clozapine administration. Upon CNO administration, only one patient had detectable plasma DCLOZ levels. 5. The interconversion process of clozapine and CNO could partially account for the wide interpatient variability reported for clozapine plasma concentrations in schizophrenic patients.

Voltage-sensitive dyes for monitoring multineuronal activity in the intact central nervous system

Optical monitoring of activity provides new kinds of information about brain function. Two examples are discussed in this article. First, the spike activity of many individual neurons in small ganglia can be determined. Second, the spatiotemporal characteristics of coherent activity in the brain can be directly measured. This article discusses both general characteristics of optical measurements (sources of noise) as well as more methodological aspects related to voltage-sensitive dye measurements from the nervous system.

Principles of drug administration in renal insufficiency

Normal renal function is important for the excretion and metabolism of many drugs. Renal diseases which affect glomerular blood flow and filtration, tubular secretion, reabsorption and renal parenchymal mass alter drug clearances and lead to the need for alterations in dosage regimens to optimise therapeutic outcome and minimise the risk of toxicity. Renal disease is increasing and the cost of care has risen progressively over the past decade. Part of these costs is related to inappropriate drug therapy and excessive drug use. Although there are a variety of methods for evaluating the various aspects of renal function, the most practical and commonly used clinical measure of renal function is estimated creatinine clearance (CLCR) as a marker for glomerular filtration. This is useful since alterations in drug clearance are proportional to alterations in CLCR, and this relationship is used as the basis for changing doses and dosage intervals for drugs which are largely renally excreted. Two populations, neonates and the elderly, are at risk of inappropriate drug dosage due to physiological changes in renal function. Estimated CLCR may not be the best method of evaluating renal function in these patients, and dosage regimens should be carefully considered. Renal insufficiency and concurrent drug therapy used in these populations can either increase or decrease drug absorption, depending on the particular agent. Drug distribution may be altered in renal insufficiency due to pH-dependent protein binding and reduced protein (primarily albumin) levels. Interestingly, renal disease may affect hepatic as well as renal drug metabolism; the exact mechanisms for these changes are not well understood. The most important quantitative pharmacokinetic change is excretion. Glomerular filtration and tubular process may both be affected but not to the same extent, and the type of renal disease may differentially affect filtration and excretion. Drug removal by dialysis is dependent on a number of factors, including the characteristics of a particular drug and the type of dialysis and equipment used. Therapeutic outcomes may be evaluated using end-points such as plasma concentrations, patient outcomes such as reduction in fever or negative cultures, and system-wide changes such as drug-use or laboratory-use patterns.

Plasma alpha-one acid glycoprotein and haloperidol concentrations in schizophrenic patients

Thirty six schizophrenic patients were randomly assigned to placebo or haloperidol treatment for 6 weeks. Blood samples to measure plasma alpha-one acid glycoprotein (AAG), haloperidol and reduced haloperidol concentrations were obtained at baseline and weeks 2, 4, and 6. Blood samples were obtained 10-12 h after the evening dose and prior to the morning dose. Haloperidol and reduced haloperidol was assayed by HPLC with electrochemical detection. Plasma AAG levels were assayed by radial immunodiffusion. Patients were clinically assessed by the Brief Psychiatric Rating Scale (BPRS) and Abnormal Involuntary Movement Scale at baseline and weeks 2, 4, and 6. BPRS scores did not significantly decrease during placebo treatment, although a slight drop in plasma AAG levels was found. Haloperidol produced a significant decrease in BPRS scores and plasma AAG levels. Mean plasma haloperidol levels were 12.9 +/- 14.7 ng/ml at week 6. Significant correlations between decreasing BPRS scores and plasma AAG levels were not found with only a strong trend at week 2 (r = 0.445, p = 0.073). The role of AAG and psychotropic drug disposition in psychiatric patients requires further evaluation.

Lack of pharmacokinetic interaction between buspirone and haloperidol in patients with schizophrenia

The pharmacokinetic interaction between buspirone and haloperidol was evaluated in schizophrenic patients in two different groups. In both groups, haloperidol doses (10-40 mg/day) remained constant for 6 weeks before the addition of buspirone 10 mg three times daily. Serial blood samples were obtained from the 11 patients in group I at baseline (before addition of buspirone) and after administration for 24 hours. The pharmacokinetic parameters of haloperidol were determined alone and with coadministration of buspirone. In group II, buspirone 10 mg three times daily was added to treatment with haloperidol in 27 patients. Blood samples were obtained before addition of buspirone and at weeks 2 and 6 of treatment with buspirone. Samples were obtained 10 to 12 hours after administration of the evening dose and before the morning dose. Haloperidol and its metabolite, reduced haloperidol (RH), were assayed by means of high-performance liquid chromatography with electrochemical detection. Significant changes in the pharmacokinetic parameters of haloperidol were not found in group I; a mean increase in the half-life (t1/2) of haloperidol from 21.5 to 28.1 hours was observed, but this finding was not statistically significant. Under steady-state conditions, plasma levels of haloperidol in the patients in group II did not change significantly from baseline to week 6. Plasma concentrations of RH remained unaltered in both groups. The results indicate that coadministration of buspirone does not markedly affect the pharmacokinetics or plasma concentrations of haloperidol.

Conditioned enhancement of the early component of the rat eyeblink reflex

Conditioned enhancement of the rat eyeblink reflex was studied using as a response measure the electromyogram (EMG) in the orbicularis oculi (oo) muscle, which is responsible for the active force generating eyelid closure. During a reflex eyeblink, the EMG evidences both a short-latency (R1) and a long-latency (R2) component, mediated by different circuits. The R2 response exhibits several experience- or use-dependent modifications. We were interested in the modifiability of the neurophysiologically simpler R1 response. Experiments were designed to determine whether the R1 response can be enhanced by a conditioned stimulus (CS) that has been explicitly paired with an aversive unconditioned stimulus (US). The R1 response was elicited by electrical stimulation of the supraorbital branch of the trigeminal nerve. Following long-delay conditioning, the CS produced a significant R1 enhancement and latency decrease that were dependent upon explicit CS-US pairings. The CS by itself produced no significant EMG response, consistent with a modulatory rather than additive effect. This is the first demonstration that the R1 response can be associatively modulated. Based on other evidence, we hypothesize that the CS-produced enhancement results from a relatively direct projection from the amygdala to the R1 circuit. As an index of aversive conditioning, R1 enhancement may prove to be a useful expression system because it offers high temporal resolution and the underlying circuitry is relatively simple-the shortest path from the fifth nerve to the muscle consisting of only two central synapses.

Disposition of remoxipride in Chinese schizophrenic patients

The disposition of remoxipride was evaluated in 13 male chronic schizophrenic patients. A single 150 mg dose of remoxipride was administered and blood sampling performed over the following 48 hours. The mean (SD) oral clearance and half-life of remoxipride were 74.46 (25.9) ml/min and 5.46 (0.87) hours, respectively. The mean (SD) AUC for remoxipride was 25,320 (9,820) ng.h/ml. A wide interpatient variability was observed. Compared to Caucasian studies there were no significant differences in the disposition of remoxipride.