The pitch of a mistuned harmonic: evidence for a template model

A harmonic of a periodic complex tone can be heard out as a separate entity if the harmonic is slightly mistuned from its correct frequency. Pitch matching experiments show that the pitch of such a mistuned harmonic differs systematically from its frequency. The shift in pitch is found to be an exaggeration of the frequency mistuning. This article considers two classes of model for the pitch shift. In the first class are tonotopically local interaction models which attribute the pitch shift to interactions between the mistuned harmonic and neighboring harmonics, where the neighborhood is established by peripheral filtering. The second class of model attributes the pitch shift to a contrast between the mistuned harmonic and a broadband harmonic template. This article describes six pitch matching experiments using complex tones having spectral gaps, strategically chosen to compare local interaction and template models. The results show that when a competition is set up between local interactions and a template, the template proves to be dominant. A parallel between the pitch shifts of mistuned harmonics and periodicity pitch, also attributed to a harmonic template, is seen as the frequency range of the mistuned harmonic is changed. Tonotopically local influences are evident in several experiments, but they are of secondary importance.

Bioactive kaurane diterpenoids from Annona glabra

Phytochemical analysis of the fruits of Annona glabra yielded two new kaurane diterpenoids, annoglabasin A (methyl-16 beta-acetoxy-19-al-ent-kauran-17-oate)(1) and annoglabasin B (16 alpha-hydro-19-acetoxy-ent-kauran-17-oic acid)(2), along with 11 known kaurane derivatives (3-13). The structures of the new compounds were established by spectral and chemical evidence. Among these, methyl-16 alpha-hydro-19-al-ent-kauran-17-oate (11) exhibited mild activity against HIV replication in H9 lymphocyte cells, and 16 alpha-17-dihydroxy-ent-kauran-19-oic acid (4) showed significant inhibition of HIV-reverse transcriptase.

Evidence for the ability of nucleophosmin/B23 to bind ATP

By taking advantage of its ability to be retained by ATP-agarose, we have demonstrated that nucleophosmin/B23 is capable of binding ATP. The specificity of the binding was confirmed by the absence of significant binding to AMP-agarose and by its loss when nucleophosmin/B23 in nuclear extracts was preincubated with ATP. Preincubation of the nuclear extracts with other ribonucleotide triphosphates (GTP, CTP, UTP) did not compete for the binding of nucleophosmin/B23 to ATP-agarose. The purified recombinant nucleophosmin/B23 was also able to be retained by ATP-agarose. The Kd for binding of ATP to the purified recombinant nucleophosmin/B23, on the basis of retention on a nitrocellulose membrane, was 86.5+/-8.3 microM; the number of binding sites was 0.68 per nucleophosmin/B23 protein molecule. To determine the possible ATP-binding site of nucleophosmin/B23, various deletion clones including the two mutants in which the putative ATP-binding sequence had been deleted were constructed. Deletion of the portions of the molecule (residues 83-152 and 185-240) had little effect on the ATP binding. The C-terminal deleted mutant (residue 242 to the C-terminus deleted) lost most of its ability to be retained by ATP-agarose and to bind [alpha-32P]ATP on a nitrocellulose membrane. The results indicate that the C-terminal portion (residues 242-294) contains the essential ATP-binding site of nucleophosmin/B23.

A 1 log N parallel algorithm for detecting convex hulls on image boards

By finding the maximum and minimum of {yi-mxi|1=or<i=or<N} for certain slopes m, we propose here a simple and fast parallel algorithm to obtain the convex hull of N arbitrarily given points on an image board, The mathematical theory needed is included, and computation time is 1 log N.

Regional gene mapping using mixed radiation hybrids and reverse chromosome painting

We describe a new approach for low-resolution physical mapping using pooled DNA probe from mixed (non-clonal) populations of human-CHO cell hybrids and reverse chromosome painting. This mapping method is based on a process in which the human chromosome fragments bearing a complementing gene were selectively retained in a large non-clonal population of CHO-human hybrid cells during a series of 12- to 15-Gy gamma irradiations each followed by continuous growth selection. The location of the gene could then be identified by reverse chromosome painting on normal human metaphase spreads using biotinylated DNA from this population of "enriched" hybrid cells. We tested the validity of this method by correctly mapping the complementing human HPRT gene, whose location is well established. We then demonstrated the method's usefulness by mapping the chromosome location of a human gene which complemented the defect responsible for the hypersensitivity to ionizing radiation in CHO irs-20 cells. This method represents an efficient alternative to conventional concordance analysis in somatic cell hybrids where detailed chromosome analysis of numerous hybrid clones is necessary. Using this approach, it is possible to localize a gene for which there is no prior sequence or linkage information to a subchromosomal region, thus facilitating association with known mapping landmarks (e.g. RFLP, YAC or STS contigs) for higher-resolution mapping.

Dimerization of the N-terminal amphipathic alpha-helix domain of the fungal immunomodulatory protein from Ganoderma tsugae (Fip-gts) defined by a yeast two-hybrid system and site-directed mutagenesis

A fungal immunomodulatory protein (Fip-gts) was purified from Ganoderma tsugae. The DNA encoding Fip-gts was isolated from a cDNA library of G. tsugae by reverse transcriptase-polymerase chain reaction. The complete amino acid sequence of Fip-gts, deduced from the nucleotide sequence of the cDNA, was the same as LZ-8 isolated from Ganodermn lucidum. Recombinant Fip-gts was expressed as a glutathione S-transferase fusion protein in Escherichia coli with a yield of 20 mg/liter of culture. Recombinant Fip-gts, purified to homogeneity, had the same blast formation stimulatory activity to human peripheral blood lymphocytes as native Fip-gts. The yeast two-hybrid system and site-directed mutagenesis were used to determine whether dimerization of Fip-gts occurred. Deletion analysis of the N-terminal amphipathic alpha-helix domain of Fip-gts identified a sequence of about 10 amino acids responsible for inducing immunomodulatory activity. Non-functional Fip-gts deletion mutants did not form dimers, whereas wild type Fip-gts did as determined by gel filtration. A mutant with deletions at Leu-5, Phe-7, and Leu-9 lost the amphipathic characteristics of the N-terminal domain and the ability to form dimers as well as its immunomodulatory activity. Fusion of Fip-gts with the DNA binding and the transactivation domains of GAL4 resulted in the activation of the lacZ activator gene, indicating the interaction of Fip-gts with it itself. The dimerization domain was further defined by analyzing the ability of the N-terminal 13 amino acids or Leu-5, Phe-7, and Leu-9 deletion mutants of Fip-gts to interact with the wild type Fip-gts. These experiments confirmed the N-terminal amphipathic alpha-helix as the dimerization domain and suggest that the dimerization of Fip-gts may play an important role in Fip-gts immunomodulatory activity.

A phase I feasibility and pharmacokinetic study of intrapleural paclitaxel in patients with malignant pleural effusions

To evaluate the feasibility and pharmacology of intrapleural (IP(L)) administration of paclitaxel, 18 patients with malignant pleural effusions were entered onto a phase I clinical study, 13 were caused by lung cancer. Following an effusion drainage rate of less than 100 ml/24 h and full expansion of the lung, patients were treated with a single instillation of pacilitaxel administered IP(L) in 500 ml of normal saline and retained for a maximum of 96h when tolerated. No systemic chemotherapy or ipsilateral thoracic irradiation was given for 4 weeks before and after the IP(L) treatment. The starting dose was 82.5 mg/m2 with the dose escalation schedule of 125, 175, 225 and 300 mg/m2. There were minimal local or systemic toxicities, such as local chest pain or myelosuppression, even when the paclitaxel dose reached 225 mg/m2. The pharmacological advantages of the IP(L) administration of paclitaxel were demonstrated by the mean exposure of the pleural cavity (area under the concentration time curve) to paclitaxel after IP(L) delivery exceeding that of the plasma by approximately 370-fold (range 55-684) and by the extraordinarily slow IP(L) clearance of paclitaxel (mean +/- SE 0.49 +/- 0.07 l/m2/day; range 0.08-1.16 l/m2/day) with significant concentrations of paclitaxel persisting within the cavity for more than 48-96 h after a single IP(L) instillation. In patients with detectable plasma paclitaxel levels, the plasma levels achieved exceed the minimal concentrations that are required to induce cytotoxic effects in vitro. Four patients had progressive dyspnea during IP(L) retention of paclitaxel solution because of treatment failure and needed drainage of effusion. One of these patients who was at the dose level of 225 mg/m2 originally had severely chronic obstructive lung disease, developed acute respiratory failure, refused mechanical ventilation support and succumbed to respiratory failure. No further patients were included after this event. Antitumor effect was shown by four of the 15 evaluable patients having no recurrence of effusion on chest radiograph at 1 month. Most of these responders had a good performance status, normal pretreatment pleural pH and/or glucose compared with the non-responders. We conclude that paclitaxel at a dose level of 175 or 225 mg/m2 is feasible for use intrapleurally. It could be considered for incorporation into treatment programs for patients with less advanced thoracic tumors with carcinomatous pleuritis or with IP(L) tumors following surgical debulking.

Molecular cloning and expression of a fungal immunomodulatory protein, FIP-fve, from Flammulina velutipes

FIP-fve, a fungal immunomodulatory protein, was isolated from the fruiting bodies of the edible mushroom, Flammulina velutipes. FIP-fve was shown to stimulate blast-forming activity of human peripheral blood lymphocytes and gene expression of interleukin-2, interferon-gamma and tumor necrosis factor-alpha. Repeated administration of FIP-fve to mice inhibits the Arthur and systemic anaphylaxis reactions. FIP-fve cDNA was cloned and sequenced, and the amino acid sequence of FIP-fve deduced from the nucleotide sequence is identical to that previously determined by protein sequencing. FIP-fve cDNA was amplified by polymerase chain reaction, ligated into the expression vector, pGEX-2T, and expressed in Escherichia coli as a fusion protein of glutathione S-transferase (GST) and FIP-fve. The GST-FIP-fve fusion protein was soluble, and the yield of recombinant FIP-fve was about 5 mg/L of induced culture. The recombinant FIP-fve was obtained by cleaving the GST-FIP-fve fusion protein with thrombin and purifing to homogeneity. The recombinant FIP-fve had about 50% of the immunomodulatory activity of the native FIP-fve.

Identification of amino acid residues of abrin-a A chain is essential for catalysis and reassociation with abrin-a B chain by site-directed mutagenesis

Abrin is a toxic protein consisting of two subunits, an enzymatic A chain (ABRaA) and a lectin-active B chain (ABRaB), linked by a disulfide bond. Site-directed mutagenesis was performed using PCR to study how the conserved amino acid residues, Tyr74, Tyr113, Glu164 and Trp198, around the active site of ABRaA are involved in enzyme catalysis, enzyme-substrate recognition and reassociation of ABRaA with ABRaB. The protein biosynthesis inhibitory activities of Y74F, Y113F and W198F were decreased moderately to that of wild type reABRaA, while that of E164Q decreased dramatically. Kinetic analysis showed that the kat of Y74F, Y113F and W198F resembled that of wild type, while the Km increased significantly. W198F did not reassociate with ABRaB to form heterodimers, while Y74F, Y113F and E164Q did. SDS-PAGE analysis of ABRaA treated with trypsin showed that reABRaA, Y74F, Y113F and E164Q survived digestion, whereas W198F was not protected from digestion. CD spectra revealed that W198F showed significant conformational changes. These observations suggest that E164 is directly involved in catalysis, and Tyr74, Tyr113 and Trp198 in substrate binding, while Trp198 also plays an important role in maintaining the conformation of ABRaA required for its reassociation with ABRaB.

Fip-vvo, a new fungal immunomodulatory protein isolated from Volvariella volvacea

A new fungal immunomodulatory protein (Fip) has been purified from the edible mushroom, Volvariella volvacea, and designated Fip-vvo. Analysis of the purified protein by SDS/PAGE followed by Coomassie Blue staining demonstrated that Fip-vvo is a single polypeptide with an apparent molecular mass of 15 kDa. Periodic acid/Schiff staining showed that this single polypeptide lacks carbohydrates. Using an in vitro bioassay measuring blast-formation stimulatory activity, Fip-vvo was shown to stimulate the maximum proliferation of human peripheral blood lymphocytes at a concentration of 5 microg/ml. Fip-vvo was capable of agglutinating rat red blood cells. Neither haemagglutination nor mitogenic activities were inhibited by mono- or dimeric sugars. In vivo, repeat administration of Fip-vvo greatly reduced the production of BSA-induced Arthus reaction in mice, whereas little effect was observed on the prevention of systemic anaphylaxis reactions. The selectively enhanced transcriptional expression of interleukin (IL)-2, IL-4, interferon-gamma, tumour necrosis factor-alpha, lymphotoxin and IL-2 receptor by Fip-vvo was also demonstrated by reverse transcriptase-PCR. This finding suggests that Fip-vvo exerts its immunomodulatory effects via cytokine regulation. In addition, the complete amino acid sequence of Fip-vvo was obtained by direct protein sequencing. This protein consists of 112 amino acid residues with a blocked N-terminal end and has a calculated molecular mass of 12667 Da not including the N-terminal blocking group. By gel filtration analysis, Fip-vvo exhibited a molecular mass of 26 kDa for the native molecules in PBS. This result indicates that native Fip-vvo is most likely a non-covalently associated homodimeric molecule.

On the Duifhuis pitch effect

An effect discovered by Duifhuis [J. Acoust. Soc. Am. 48, 888-893 (1970)], wherein an omitted high harmonic of a periodic complex tone is found to have an audible pitch, is extended to a variety of new broadband signal conditions. The effect is found to exist for flat spectra and spectra decreasing at 6 dB/octave, independent of phases as long as they are constant. The effect exists for alternating phases and Schroeder phases. It can generate a missing-fundamental pitch. Pitch and loudness matching experiments support the status of the omitted harmonic as an objective tone in the signal. Further experiments using narrower bands challenge the traditional explanation for the effect, which attributes it to short-term frequency analysis by peripheral auditory filters. Instead, the experiments suggest that different peripheral channels must be combined, maintaining some phase information, to generate the effect.

An ionizing radiation-sensitive CHO mutant cell line: irs-20. IV. Genetic complementation, V(D)J recombination and the scid phenotype

The genetic defect responsible for hypersensitivity of Chinese hamster ovary (CHO) irs-20 cells to ionizing radiation was found to be recessive in nature and could be complemented to produce wild-type radiosensitivity in irs-20/human hybrids. The radiosensitivities of six hybrid clones were determined based on their colony-forming ability under continuous irradiation at 6 cGy/h. A parallel cytogenetic analysis revealed a concordance between the presence or absence of human chromosome 8 and the resistant or sensitive phenotype. Confirming evidence was obtained using human chromosome 8-specific PCR primers. Positive amplification was obtained in hybrids with wild-type radiosensitivity, while no amplification was obtained in sensitive hybrids. Complementation analysis between radiosensitive CHO irs-20 and murine scid cell lines was carried out to determine whether the defects leading to their ionizing radiation hypersensitivity could be corrected by genetic complementation in the hybrids. Complementation did not occur. A transient V(D)J recombination assay after the introduction of the RAG1 and RAG2 genes indicated that the V(D)J recombination ability of the CHO irs-20 cells was about 10% of that for the CHO wild-type cells for signal join formation with an 80% joining fidelity and only 3% of the parental level for coding join formation. These data show that murine scid and irs-20 mutant hamster cells fall into the same complementation group and show similar defects in V(D)J recombination.

Establishment and characterization of an abrin-resistant cell line

An abrin-resistant cell line, CHOR 3-4, was isolated from CHOK1 cells which were resistant to a high concentration of abrin (160 ng/ml), and had a 1,000-fold higher resistance to abrin that of CHOK1 cells. CHOR 3-4 cells were about 25-fold more resistant than CHOK1 cells to the N-glycosidase activity of abrin, which was measured by hydrolyzing the N-glycosidic bond of adenine 4324 nucleotide from 3' end of mammalian 28S rRNA. However, the isolated polysomes of CHOR 3-4 cells had the same sensitivity to abrin as those of CHOK1 cells. On measuring the binding of 125I-abrin to CHOR 3-4 cells, it was decreased to about 20% that of CHOK1 cells. This indicates that the mechanism of the resistance of CHOR 3-4 to abrin is due to the alteration of glycoproteins or glycolipids of cell membrane.

Inhibitory effect of dopamine on dorsomedial arcuate neurons in rat brain slices: potentiation by coadministration of cocaine

Whether dopamine (DA) can have a direct effect on the tuberoinfundibular dopaminergic neurons has been a controversial issue. The present report used single-unit recording of neurons in dorsomedial region of the arcuate nucleus, where most tuberoinfundibular dopaminergic neurons are located, to study this question. By focusing our recording in this region, we found that DA in 25-250 nmol ranges inhibited a significant number of arcuate neurons tested (74.2% of 182 units). The inhibitory effect of DA was not only prominent in most cases, it also persisted in low Ca2+, high Mg2+ solution in several trials. Cocaine, a drug of abuse whose main effect is due to its inhibition of DA transporters and increasing the DA concentration in synaptic clefts, also inhibited a significant number of arcuate neurons by itself (51.5% of 97 units), although its effects were lesser than those of DA. Nevertheless, when coadministered with DA, cocaine significantly potentiated the inhibitory effect of DA in 82% of DA-responsive units (n = 39). These results clearly demonstrate that DA exhibits a predominantly inhibitory effect on presumed DA neurons in dorsomedial arcuate nucleus. The effects of cocaine further support this notion.

Endoscopic sympathectomy treatment for craniofacial hyperhidrosis

OBJECTIVE

To present endoscopic T-2 sympathectomy as a minimally invasive therapy for craniofacial hyperhidrosis (CH).

DESIGN

Follow-up study of 30 patients with CH treated by the new method in a 4-year period. The duration of follow-up was from 8 to 44 months (mean, 15 months).

SETTING

University hospital.

PATIENTS

Thirty consecutive patients with CH (18 men, 12 women) treated by the new method. All patients were essentially in good health except that they suffered from distressing CH to the extent that their daily activities were often disturbed. Their ages ranged from 7 to 63 years (mean age, 42.8 years).

INTERVENTION

Endoscopic sympathectomy on both sides was carried out in a 1-stage operation for all patients.

MAIN OUTCOME MEASURES

The patients were interviewed 1 week and then 3 months after surgery and then followed up by telephone interview about the alleviation or recurrence of CH and complications.

RESULTS

All of the treated patients obtained a satisfactory alleviation of CH. One case was complicated by a mild and transient ptosis of the left eye. No recurrence of CH was noticed during the follow-up period.

CONCLUSIONS

This therapeutic procedure is minimally invasive and effective. It causes minimal discomfort and was associated with no major complications in this series. The patients require only an overnight hospital stay and the operation scars are small. Endoscopic sympathectomy has proven to be an effective method in treating patients with distressing CH.

The importance of the helix 2 region for the cis-cleaving and trans-cleaving activities of hepatitis delta virus ribozymes

The sequence, secondary structure, and size requirements of the helix 2 region (H2) of a cis-acting hepatitis delta virus ribozyme Rz 1 were examined in this study. Mutational analysis was performed, and the cleavage rate of each H2 mutant of Rz 1 was assayed. We found that H2 could be elongated to twice its original size without affecting ribozyme folding while the shortening of H2 by one base pair severely decreased autolytic activity. In addition, the maintenance of the Watson-Crick base-pairing interactions of the last base pair of H2 (A16U58) was not critical for cis-cleavage reaction. Nevertheless, mutants with an AA, an AG, an AC, or a GG pair at the bottom of H2 were less active, and the sequence of the H2/H3 interface might affect the stability of the catalytic core. The negative effects on ribozyme folding, such as the destabilization of H2, the unfavorable sequences at the last base pair of H2 as well as the disruption of the continuity of H2 and H3, could be compensated for by elongating the H2 region of the corresponding mutants. The extension of H2 may alter the conformation of ribozyme molecules; in addition, it stabilized the catalytic core and enhanced the resistance to formamide. Finally, for a trans-acting ribozyme and its substrate that require the formation of H1, H2, and H4 to reconstitute the autocatalytic domain of HDV RNA, the extension of H2 stabilized the substrate/ribozyme complex and speeded up the cleavage rate but hindered the product release process.

Probing the Domain Structure of Abrin-a by Tryptic Digestion

Abrin-a is a potent plant toxin that consists of A and B chains linked by a disulfide bond. The abrin-a A chain (AaTA) has N-glycosidase activity while the abrin-a B chain (AaTB) has galactose-binding activity. By partial tryptic digestion, the domain structure of abrin-a was investigated. Seven tryptic fragments with molecular masses greater than 3500 Da were isolated and characterized. One fragment, designated T-21 and consisting of 153 amino acid residues, contained the major part of the second domain of AaTB and, after cross-linking of T-21 with glutaraldehyde, the reaction product had the same level of hemagglutinating activity as native abrin. When the T-21 fragment was conjugated with AaTA, the conjugate inhibited protein biosynthesis in HeLa cells. This suggests that the T-21 fragment is able to bind specifically to cells; its conjugate facilitates membrane translocation of AaTA into cells and consequently inhibits protein biosynthesis. T-21, with a molecular mass less than AaTB, is therefore a potentially useful substance for the preparation of immunotoxins.

Minimally invasive surgery: video endoscopic thoracic sympathectomy for palmar hyperhidrosis

Palmar hyperhidrosis (PH) is a common disorder in Taiwan. It often causes social embarrassment and occupational handicaps. So far, there has been no satisfactory treatment for PH. In 1990, we first developed a minimally invasive technique: video endoscopic sympathectomy to treat PH. The procedure has subsequently proven to be a standard treatment for PH. In this study, a survey of 9988 cases of PH patients from 17 hospitals in Taiwan treated by this method during the past 5 years is presented. Although there were some variations in the model of anaesthesia, technique and extent of sympathectomy, the postoperative results were generally satisfactory. Both sides of sympathectomy were mostly accomplished within half an hour in one stage. The operative scars were tiny and concealed in the axillary region. The patients were discharged from the hospital after an overnight stay. Complications such as pneumothorax, haemothorax (0.3%) or Horner's syndrome (0.1%) were rare. There was no surgical mortality in this series. The most common complication was compensatory hyperhidrosis which was usually mild to moderate and tolerable after reassurance. The recurrence rate of PH was approximately 1% in the first year and less than 3% during the 3 years of follow up. Intraoperative monitoring of palmar skin temperature (PST) was advocated to confirm an adequate sympathectomy warranting a definite result. En bloc ablation of T2 segment invariably resulted in a rise of PST to about 2 degrees C and was considered as an adequate extent of sympathectomy for PH. The refined technique was extended to treat young children with PH and patients with craniofacial hyperhidrosis. The therapeutic results were generally excellent with minimal morbidity and rare recurrence. It is concluded that video endoscopic en bloc T2 sympathectomy is a simple, minimally invasive and effective treatment for both adults and children with PH and also for patients with craniofacial hyperhidrosis.

Prolonged pertussis toxin treatment affects morphine's action on tuberoinfundibular dopaminergic neuron activity and on prolactin secretion

The effects of pertussis toxin (PTX) pretreatment on basal and morphine-affected changes of tuberoinfundibular dopaminergic (TIDA) neuron activity and serum prolactin level were tested in this study. Adult female Sprague-Dawley rats, ovariectomized and treated with a long-acting estrogen (polyestradiol phosphate, 0.1 mg/rat, s.c.), were used. The activity of TIDA neurons was determined by measuring the turnover rate of dopamine (DA), and the concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) or 3,4-dihydroxyphenylalanine (DOPA) in the median eminence. Acute (30-90 min) treatment of PTX had no significant effect on any of the parameters measured. Prolonged (24 h) treatment of PTX significantly reduced morphine's inhibitory effect on TIDA neuron activity (using DOPA, but not DOPAC as the index), and stimulatory effect on PRL release. Basal TIDA neuron activity as determined by median eminence DOPAC concentration, DOPA accumulation, or DA rate constant was not significantly altered by PTX. Median eminence DA level, however, was significantly reduced. These results suggest that a pertussis toxin-sensitive GTP-binding protein may be responsible for the maintenance of TIDA neurons, and for mediation of the inhibitory effect of morphine on TIDA neuron activity, and in turn, the stimulation of prolactin secretion.

Epicutaneous exposure of protein antigen induces a predominant Th2-like response with high IgE production in mice

Hapten-induced contact hypersensitivity has been well-characterized in humans as well as in animal models. However, it is not clear whether or not protein Ag can directly sensitize epicutaneously and induce a primary immune response. We demonstrated in this study, for the first time, that through epicutaneous exposure protein Ag in the absence of adjuvant sensitizes animals and induces a predominant Th2-like response. Furthermore, mice receiving repeated protein Ag sustained elevated levels of specific IgE. This animal model can be used to investigate the molecular mechanism controlling the differential Th1/Th2 development in skin diseases.

Epicutaneous exposure of protein antigen induces a predominant Th2-like response with high IgE production in mice

Hapten-induced contact hypersensitivity has been well-characterized in humans as well as in animal models. However, it is not clear whether or not protein Ag can directly sensitize epicutaneously and induce a primary immune response. We demonstrated in this study, for the first time, that through epicutaneous exposure protein Ag in the absence of adjuvant sensitizes animals and induces a predominant Th2-like response. Furthermore, mice receiving repeated protein Ag sustained elevated levels of specific IgE. This animal model can be used to investigate the molecular mechanism controlling the differential Th1/Th2 development in skin diseases.

The association between lung innate immunity and differential airway antigen-specific immune responses

The mechanisms involved in the differential regulation of airway immune responses in atopic versus non-atopic individuals are poorly understood. In this study, the association between non-specific immunity and the differential airway antigen-specific immune responses was examined in a murine model. The disparity in antigen-specific IgE and IgG2a productions between the two strains of mice was observed to be significant. C57BL/6J mice were much more efficient than BALB/cJ mice in making IgE antibody to inhaled ovalbumin (OVA) antigen. On the contrary, BALB/cJ mice did make more IgG2a antibodies than C57BL/6J mice to inhaled OVA. These findings suggest that in C57BL/6J mouse strain a predominant Th2 type of immune response develops in response to inhaled OVA antigen. In contrast, BALB/cJ mice mount a Th1 type of immune response to aerosolized OVA antigen. Furthermore, after lipopolysaccharide (LPS) stimulation, the IL-12 mRNA expression of lung-derived cells from BALB/cJ mice was higher than that from C57BL/6J cells. However, the lung-derived cells of C57BL/6J mice stimulated by LPS produced higher levels of IL-10 and prostaglandin E2 than BALB/cJ lung-derived cells did. Therefore, our study demonstrated that the difference of lung-derived cells in their ability to produce cytokine and prostaglandin between BALB/cJ and C57BL/6J mice correlates well with the type of the airway antigen-specific immune effector functions.

Effects of circular permutation on the cis-cleavage reaction of a hepatitis delta virus ribozyme: application to trans-acting ribozyme design

In this study we investigated the effects of the relocation of the wild type termini on the folding of a cis-cleaving RNA Rz 1 that was modified from the autolytic domains of hepatitis delta virus (HDV) RNA. Ten circularly permuted (CP) isomers of this ribozyme were synthesized. The structure homogeneity of RNA molecules, the molar ratio of the active species that undergoes cis-cleavage, and the rate of cis-cleavage were examined for each construct. CP isomers with new termini in H1 or at the junction of H2-H3, H1-J1/4, J1/4-H4, or H4-J4/2 of the proposed pseudoknot-like structure were inactive. The single breaks of phosphodiester bond in H2, J1/2, Lp4, and at the 3'-end of Lp3 decreased but did not abolish autolytic activity. The structural heterogeneity of RNA molecules may account for the limited cis-cleavage of the latter three isomers. The findings of circular permutation analysis were used as the basis for designing an active trans-cleaving ribozyme by dividing the cis-cleaving ribozyme into two subdomains at J1/2 and Lp4. The ribozyme subdomain catalyzed the site-specific cleavage of the circularly permuted composite substrate RNA in trans. Thus, the structure of HDV autolytic domain could be re-formed after two subdomains were associated through the base-pairing interactions of H1, H2, and H4.

Crystallization and preliminary x-ray analysis of volvatoxin A2 from Volvariella volvacea

Volvatoxin A2, an ion channel disturbed cardiotoxic and hemolytic protein from the edible mushroom, Volvarilla volvacea, has been crystallized by the vapor diffusion method using polyethylene glycol 4000 and ammonium sulfate in sodium acetate buffer pH 4.6. The best crystals belong to the monoclinic space group C2 with unit cell dimensions a = 155.25 angstroms, b = 58.06 angstroms, c = 116.92 angstroms, and beta = 119.5 degrees. These crystals diffract to at least 2.2 angstroms and there are four molecules of molecular weight 24 kDa per asymmetric unit with a solvent content of 48%.

Home care for the urban chronically ill elderly in the People's Republic of China

This study examines the home care situation of seventy-five urban chronically ill men and women and their caregivers in three cities in the People's Republic of China. It documents the type of home care provided, the severity of illness, and the dependency in activities of daily living in order to appreciate the complexity of these care situations. The findings reveal that women serve as the caregivers in the majority of the cases and often they are elderly spouses with health problems of their own. The physical, social, psychological, and financial problems experienced by these patients create an enormous burden for the caregivers whether spouses or younger family members coming home from work to a second shift. If alternatives to home care, such as nursing homes, were available, 54 percent of these caregivers would be willing to institutionalize their elderly relative. All caregivers express the need for more assistance in providing home care. This study raises questions regarding the role of the family, the state, and specifically the health care system in caring for the elderly chronically ill in light of their increasing numbers in the population.

Growth suppression of human colorectal carcinoma in nude mice by monoclonal antibody C27-abrin A chain conjugate

PURPOSE

The aim of this study was to assess an immunotoxin, monoclonal antibody C27-abrin A chain conjugate (MAAAC), that might be effective in the treatment of colorectal carcinoma.

METHODS

The immunotoxin was prepared by a specific monoclonal antibody against carcinoembryonic antigen (CEA), monoclonal antibody C27, linked to N-succinimidyl-3-(2-pyridyldithio)propionate and then coupled covalently to the toxic abrin-A chain to synthesize MAAC. The therapeutic role of this immunotoxin in suppressing the in vitro and in vivo growth of CEA-secreting human colorectal cancer cells (LS174T) was assayed by methods of protein biosynthesis inhibition, cell colony proliferation, and treatment of tumor cells before and after inoculation in nude mice.

RESULTS

We found that MAAC effectively suppressed the growth of LS174T in culture medium and completely eradicated cells in inoculated nude mice. In contrast, irrelevant immunotoxin antiferritin-abrin A chain conjugate and isotype-matched monoclonal immunoglobin (MOPC21IgG1)-abrin A chain conjugate did not cause such effects. The in vitro toxicity was highly specific because the conjugate (MAAC) inhibited de novo protein biosynthesis, impeded growth, and caused death of cells possessing surface CEA determinants. The 50 percent inhibition dose values of the conjugate for colonogenic survival and for protein biosynthesis in LS174T cells were 0.09 microgram/ml and 0.06 microgram/ml, respectively. Colon survival was inhibited 96.3 percent after prolonged MAAC treatment. MAAC showed selective cytotoxicity; the inhibitory effect of MAAC to the CEA-secreting LS174T cells over the CEA-nonsecreting human embryonic kidney cells was 16-fold.

CONCLUSION

These results indicate that MAAC may be of benefit in therapy during or soon after resection of colorectal carcinoma or in patients who have micrometastasis.

Native and/or asialo-Tamm-Horsfall glycoproteins Sd(a+) are important receptors for Triticum vulgaris (wheat germ) agglutinin and for three toxic lectins (abrin-a, ricin and mistletoe toxic lectin-I)

The binding properties of human Tamm-Horsfall Sd(a+) urinary glycoprotein (THGP) and asialo-THGP with Triticum vulgaris agglutinin(WGA) and three toxic lectins (abrin-a, ricin, and Mistletoe toxic lectin-I) were investigated by quantitative precipitin and precipitin inhibition assays. Both glycoproteins reacted strongly with abrin-a, precipitating over 80% of the lectin nitrogen tested. THGP also bound well to mistletoe toxic lectin-I and precipitated 86% of this lectin added, while the precipitability of its asialo product decreased by 28%. The native glycoprotein completely precipitated the WGA added, but its reactivity was reduced dramatically after desialylation. On the contrary, the poor reactivity of THGP with ricin increased substantially after removal of sialic acid and completely precipitated the lectin added. The glycoprotein-lectin interactions were inhibited by one or several of the following haptens, p-NO2-phenyl alpha GalNAc, p-NO2-phenyl beta GalNAc, Gal beta 1-->4GlcNAc, Gal beta 1-->4Glc, GlcNac beta 1-->4GlcNAc and/or GlcNAc. From the above results, it is concluded that native and/or Tamm-Horsfall glycoproteins serve as important receptors for these three toxic lectins and for WGA.

Differential inhibition of reverse transcriptase and cellular DNA polymerase-alpha activities by lignans isolated from Chinese herbs, Phyllanthus myrtifolius Moon, and tannins from Lonicera japonica Thunb and Castanopsis hystrix

Two lignans, phyllamycin B and retrojusticidin B isolated from Phyllanthus myrtifolius Moon have been demonstrated to have a strong inhibitory effect on human immunodeficiency virus-1 reverse transcriptase activity (HIV-1 RT), but much less inhibitory effect on human DNA polymerase-alpha (HDNAP-alpha) activity. Fifty percent inhibitory concentrations of phyllamycin B and retrojusticidin B were determined to be 3.5 and 5.5 microM for HIV-1 RT, and 289 and 989 microM for HDNAP-alpha, respectively. The mode of inhibition was found to be non-competitive inhibition with respect to template-primer and triphosphate substrate. Several tannins such as caffeoylquinates (CQs) isolated from Lonicera japonica Thunb, galloylquinates (GQs) and galloylshikimates (GSs) purified from Castanopsis hystrix were shown to have a much less selective inhibitory effect on HIV-1 RT.

Crystal structure of abrin-a at 2.14 A

The crystal structure of abrin-a, a type II ribosome-inactivating protein from the seeds of Abrus precatorius, has been determined from a novel crystalline form by the molecular replacement method using the coordinates of ricin. The structure has been refined at 2.14 A to a R-factor of 18.9%. The root-mean-square deviations of bond lengths and angles from the standard values are 0.013 A and 1.82 degrees, respectively. The overall protein folding is similar to that of ricin, but there are differences in the secondary structure, mostly of the A-chain. Several parts of the molecular surface differ significantly; some of them are quite near the active site cleft, and probably influence ribosome recognition. The positions of invariant active site residues remain the same, except the position of Tyr74. Two water molecules of hydrogen-bonded active site residues have been located in the active site cleft. Both of them may be responsible for hydrolyzing the N-C glycosidic bond. The current abrin-a structure is lactose free; this is probably essential for abrin-a crystallization. The B-chain is a glycoprotein, and the positions of several sugar residues of two sugar chains linked to earlier predicted glycosylation sites were determined. One of the sugar chains is a bridge between two neighboring molecules, since one of its mannose residues is connected to the galactose binding site of the neighboring molecule. Another sugar chain covers the surface of the B-chain.

Transforming growth factor-beta 1 primes macrophages for enhanced expression of the nitric oxide synthase gene for nitric oxide-dependent cytotoxicity against Entamoeba histolytica

Nitric oxide (NO) produced by activated macrophages is the major cytotoxic molecule for in vitro cytotoxicity against Entamoeba histolytica trophozoites. Transforming growth factor-beta 1 (TGF-beta 1) is a potent negative regulator of several macrophage functions, including NO production. In this study, we investigated the effect of TGF-beta 1 on macrophage nitric oxide synthase (mac-NOS) mRNA expression and NO production for macrophage cytotoxicity against E. histolytica trophozoites. TGF-beta 1 by itself was incapable of inducing mouse bone marrow-derived macrophage (BMM) amoebicidal activity and NO production (as measured by nitrite). In contrast, TGF-beta 1 pretreatment (4 hr) primed BMM for an enhanced amoebicidal activity of 15% and 23% in response to (interferon-gamma) IFN-gamma+tumour necrosis factor-alpha (TNF-alpha) or IFN-gamma+lipopolysaccharide LPS, concomitant with increased NO production of 85% and 27%, respectively. TGF-beta 1 pretreatment increased NO production in response to IFN-gamma+TNF-alpha/LPS stimulation in a time- and dose-dependent manner. By Northern blot analysis, the increased NO production of TGF-beta 1-pretreated BMM was preceded by markedly enhanced expression of mac-NOS mRNA. The priming effect of TGF-beta 1 on NO production was critically dependent on both a TNF-alpha (> or = 100 U) and a LPS (> or = 100 ng) triggering dose in the presence of IFN-gamma. TGF-beta 1 pretreatment enhanced TNF-alpha mRNA expression, but had no effect on TNF-alpha production in culture supernatants after 4 hr of stimulation with IFN-gamma+TNF-alpha/LPS; however, at a later time-point (16-48 hr), even though the levels of TNF-alpha mRNA expression were unaffected, TNF-alpha production was reduced. These data demonstrate that TGF-beta 1 priming for increased mac-NOS mRNA expression for NO-dependent cytotoxicity against E. histolytica in response to IFN-gamma+TNF-alpha/LPS stimulation may be involved in the modulation of a TNF-alpha triggering signal by TGF-beta 1.

Amino acid sequences of trypsin inhibitors from the melon Cucumis melo

Two squash family trypsin inhibitors, CMeTI-A and CMeTI-B, were isolated from the melon (Cucumis melo) seeds, by ion exchange chromatography, gel filtration, affinity chromatography, and high-performance liquid chromatography, and their amino acid sequences were determined. All inhibitors contain 29 amino acid residues including 6 half-cystine residues. They differ by twelve amino acid residues. These polypeptides are strong inhibitors of bovine trypsin, with Ki values of 1.6 x 10(-10) M (CMeTI-A) and 4.7 x 10(-10) M (CMeTI-B). The products of CMeTI-A and CMeTI-B cleaved at their reactive sites by tryptic digestion during the purification by trypsin-Sepharose 4B affinity column chromatography are active against trypsin activity, but a molar ratio of inhibitor to trypsin of 2:1 for trypsin-treated CMeTI-B or 1:1 for trypsin-treated CMeTI-A is required.

A new fungal immunomodulatory protein, FIP-fve isolated from the edible mushroom, Flammulina velutipes and its complete amino acid sequence

A new fungal immunomodulatory protein (FIP-fve) has been isolated and purified from the edible golden needle mushroom (Flammulina velutipes). The apparent molecular mass of FIP-fve determined by SDS/PAGE agrees well with the value of 12704 Da calculated from its amino acid composition and sequence. The complete amino acid sequence of FIP-fve was elucidated by protein sequencing techniques. FIP-fve consists of 114 amino acid residues with an acetylated amino end, and lacks methionine, half-cystine and histidine residues. FIP-fve was able to hemagglutinate human red blood cells. The immunomodulatory activity of FIP-fve was demonstrated by its stimulatory activity toward human peripheral blood lymphocytes, and its suppression of systemic anaphylaxis reactions and local swelling of mouse footpads. FIP-fve was found to enhance the transcriptional expression of interleukin-2 and interferon-gamma.

A sheep hydatid cyst glycoprotein as receptors for three toxic lectins, as well as Abrus precatorius and Ricinus communis agglutinins

The binding properties of a glycoprotein with blood group P1 specificity isolated from sheep hydatid cyst fluid with Gal and GalNAc specific lectins was investigated by quantitative precipitin and precipitin inhibition assays. The glycoprotein completely precipitated Ricinus communis agglutinin (RCA1), Abrus precatorius agglutinin (APA) and Mistletoe toxic lectin-I (ML-I). Only 1.0 microgram of P1 glycoprotein was required to precipitate 50% of 5.1 micrograms ML-I nitrogen. It also reacted well with abrin-a and ricin, precipitating over 73% of the lectin nitrogen added, but poorly or weakly with Dolichos biflorus (DBL), Vicia villosa (VVL, a mixture of A4, A2B2 and B4), VVL-B4, Arachis hypogaea (PNA), Maclura pomifera (MPL), Bauchinia purpurea alba (BPL) and Wistaria floribunda (WFL) lectins. When an inhibition assay in the range of 5.1 micrograms N to 5.9 micrograms N of lectins (ML-I, abrin-a; ricin, RCA1, and APA, and 10 micrograms P1 active glycoprotein interaction was performed; from 76 to 100% of the precipitations were inhibited by 0.44 and 0.52 mumol of Gal alpha 1-->4Gal and Gal beta 1-->4GlcNAc, respectively, but not or insignificantly with 1.72 mumol of GlcNAc. The Gal alpha 1-->4Gal disaccharide found in this P1 active glycoprotein is a frequently occurring sequence of many glycosphingolipids located at the surface of mammalian cell membranes, especially human erythrocytes and intestinal cells for ligand binding and microbial toxin attachment. The present finding suggests that the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in this P1 active glycoprotein is one of the best glycoprotein receptors for three toxic lectins (ricin, abrin-a, and ML-I) as well as for APA, and RCA1, and the result of inhibition assay implies that these lectins are recognizing part or all of the Gal alpha 1-->4Gal beta 1-->4GlcNAc sequence in the P1 active glycoprotein.

TNF-alpha expression by resident microglia and infiltrating leukocytes in the central nervous system of mice with experimental allergic encephalomyelitis. Regulation by Th1 cytokines

The inflammatory cytokines IFN-gamma and TNF-alpha have been demonstrated in various autoimmune diseases, and are thought to participate in the induction and pathogenesis of disease. TFN-alpha is a cytopathic cytokine that is cytotoxic for oligodendrocytes in vitro and has been implicated in the pathology of multiple sclerosis and its animal model experimental allergic encephalomyelitis (EAE). We used reverse transcriptase (RT)-PCR to study the kinetics, cellular source, and regulation of cytokine gene expression in the central nervous system (CNS) of SJL/J mice with myelin basic protein-induced EAE at different stages of the disease. The expression of CD3, IL-2, IFN-gamma, and TNF-alpha mRNA was barely detectable in the CNS of unmanipulated mice or mice that were immunized with adjuvant but showed no symptoms. These mRNAs were readily detectable in the CNS of mice during peak disease, then coordinately dropped to background levels during remission. Analysis of cells isolated from the CNS of mice with acute EAE showed that the Th1 cytokines, IL-2 and IFN-gamma, were produced by infiltrating CD4+ T cells. In contrast, TNF-alpha was predominantly transcribed by non-T mononuclear CNS cells, the majority of which were identified as microglia and macrophages by their Mac-1 phenotype. Microglia could be discriminated by their low expression of CD45. Incubation of freshly derived, adult microglia from normal, uninfiltrated, CNS with activated Th1 supernatant induced the production of TNF-alpha mRNA. Therefore, TNF-alpha is made by both CNS-resident microglia and infiltrating macrophages during EAE, and this production is tightly controlled by cytokines secreted by infiltrating CD4+ T cells.

TNF-alpha expression by resident microglia and infiltrating leukocytes in the central nervous system of mice with experimental allergic encephalomyelitis. Regulation by Th1 cytokines

The inflammatory cytokines IFN-gamma and TNF-alpha have been demonstrated in various autoimmune diseases, and are thought to participate in the induction and pathogenesis of disease. TFN-alpha is a cytopathic cytokine that is cytotoxic for oligodendrocytes in vitro and has been implicated in the pathology of multiple sclerosis and its animal model experimental allergic encephalomyelitis (EAE). We used reverse transcriptase (RT)-PCR to study the kinetics, cellular source, and regulation of cytokine gene expression in the central nervous system (CNS) of SJL/J mice with myelin basic protein-induced EAE at different stages of the disease. The expression of CD3, IL-2, IFN-gamma, and TNF-alpha mRNA was barely detectable in the CNS of unmanipulated mice or mice that were immunized with adjuvant but showed no symptoms. These mRNAs were readily detectable in the CNS of mice during peak disease, then coordinately dropped to background levels during remission. Analysis of cells isolated from the CNS of mice with acute EAE showed that the Th1 cytokines, IL-2 and IFN-gamma, were produced by infiltrating CD4+ T cells. In contrast, TNF-alpha was predominantly transcribed by non-T mononuclear CNS cells, the majority of which were identified as microglia and macrophages by their Mac-1 phenotype. Microglia could be discriminated by their low expression of CD45. Incubation of freshly derived, adult microglia from normal, uninfiltrated, CNS with activated Th1 supernatant induced the production of TNF-alpha mRNA. Therefore, TNF-alpha is made by both CNS-resident microglia and infiltrating macrophages during EAE, and this production is tightly controlled by cytokines secreted by infiltrating CD4+ T cells.

Use of the urine-to-blood carbon dioxide tension gradient as a measurement of impaired distal tubular hydrogen ion secretion among neonates

To evaluate the utility of the urinary-minus-blood partial pressure of carbon dioxide (U-B PCO2) gradient for the diagnosis of distal renal tubular acidosis in neonates, we measured the U-B PCO2 gradient corresponding to different urinary bicarbonate concentrations in 40 neonates. The U-B PCO2 gradient in these neonates had a significant linear relationship to the urinary bicarbonate concentration. When the urinary bicarbonate concentration was > 10 mmol/L, in all the neonates the U-B PCO2 could be increased above the 20 mm Hg level. We conclude that it is appropriate to determine the U-B PCO2 gradient as an index of distal urinary acidification and that it is a necessary test for diagnosis of distal renal tubular acidosis in neonates.

Effects of endogenous opioid peptides and their analogs on the activities of hypothalamic arcuate neurons in brain slices from diestrous and ovariectomized rats

Various endogenous opioid peptides and some of their analogs were used in this study to test their effects on the membrane activities of hypothalamic arcuate neurons in brain slices. Both ovariectomized and diestrous rats were used in the study, and freshly prepared brain slices from these animals were used for extracellular single-unit recording studies. All of the opioids exhibited potent inhibitory effects on the firing of arcuate neurons, viz., beta-endorphin inhibited 55% (n = 33), DAGO 62% (n = 21), dynorphin A 55% (n = 11), U50,488 36% (n = 39), Met-enkephalin 35% (n = 54), and DPDPE 50% (n = 8) of tested arcuate neurons from ovariectomized rats. Significantly higher percentage of inhibition was observed in slice preparations from diestrous rats for DAGO 86% (n = 22), and slightly higher for dynorphin A 59% (n = 22) and U50,488 53% (n = 15). Pretreatment with naloxone prevented most of the actions by beta-endorphin and DAGO, and nor-binaltorphimine prevented those by dynorphin A and U50,488. Most of the effects of Met-enkephalin could also be blocked by nor-binaltorphimine (67%, n = 6), but less by naltrindole (25%, n = 8). Naltrindole, however, seemed to be more effective in blocking the action of [D-Pen2,5]-enkephalin (100%, n = 2). In summary, all opioids tested exerted potent inhibitory effects upon the firing of arcuate neurons possibly through multiple opioid receptors, and the presence of ovarian hormones may have an effect on the neuron's responsiveness to opioid acting on mu type receptors.

Inactivation of Acacia confusa trypsin inhibitor by site-specific mutagenesis

Native Acacia confusa trypsin inhibitor (ACTI) contains two disulphide bonds; one is an intrachain disulphide bond (Cys40-Cys86), located in the A-chain, while the other is an interchain disulphide bond (Cys133-Cys141) connecting the A- and B-chain; the inhibitor consists of 175 amino acid residues, 136 residues in the A-chain and 39 residues in the B-chain. The putative reactive site of ACTI is located at Lys64, while for all other Kunitz family trypsin inhibitors it is at Arg64. When the Lys64 residue of ACTI was converted into Ile or Arg by site-specific mutagenesis, the K64I mutant completely lost its inhibitory activity but the K64R mutant retained most of its inhibitory activity. The C133G mutant lost its inhibitory activity while the C40G mutant did not. This suggests that the interchain disulphide bond (Cys133-Cys141) linking two beta-strands of the six-strand beta-barrel is essential for ACTI inhibitory activity, while the intrachain disulphide bond (Cys40-Cys86) connecting the two loops is non-essential.

Fluorescent spot test method for specific detection of beta-lactamases

A simple, sensitive fluorescent spot test method for specific detection of microbial beta-lactamases has been developed, based on the modification of a previously disclosed method (K. C. S. Chen, October 23, 1990, U.S. Patent 4,965,193). The new fluorescence developer used in the present study consisted of 0.5 mM HgCl2, in 0.5 M sodium citrate buffer, pH 4.5, prepared in 0.5% formaldehyde aqueous solution. A beta-lactam substrate solution consisting of a beta-lactam antibiotic with an acyl side chain containing an alpha-amino group and an alpha-phenyl group, or its derivatives, was incubated with a beta-lactamase-producing organism. One volume of the fluorescence developer was added to 4 vol of the incubated beta-lactam substrate solution, followed by heating the mixture at 45 degrees C for 10 min. The mixture was spotted on filter paper. Production of fluorophore indicated beta-lactamase activity. Each fluorophore was analyzed by TLC and its chemical identity was determined. Using ampicillin as the penicillinase substrate and cephalexin as the cephalosporinase substrate, the new method can be conveniently carried out by using dropping bottles for storing and dispensing the substrate solutions and the fluorescence developer. This modified method also provided more favorable conditions for the penicillinases to remain active during fluorescence development. Therefore, the sensitivity of the test was increased.

Tumor necrosis factor alpha augments nitric oxide-dependent macrophage cytotoxicity against Entamoeba histolytica by enhanced expression of the nitric oxide synthase gene

Nitric oxide (NO measured as nitrite, NO2-) is the major effector molecule produced by activated macrophages for in vitro cytotoxicity against Entamoeba histolytica trophozoites. In this study, we determine whether tumor necrosis factor alpha (TNF-alpha) produced by activated bone marrow-derived macrophages (BMM) is involved in the induction of the inducible NO synthase gene (mac-NOS) for NO-dependent amebicidal activity. TNF-alpha alone did not directly induce macrophage NO2- production to kill amebae; however, in combination with increasing concentrations of TNF-alpha and gamma interferon (IFN-gamma), BMM amebicidal activity and NO2- production progressively increased and showed a significant linear correlation. Antiserum to TNF-alpha and the NO synthase inhibitor NG-monomethyl L-arginine (L-NMMA) inhibited the synergistic effects of TNF-alpha and IFN-gamma. BMM activated with increasing concentrations of lipopolysaccharide (LPS) and IFN-gamma showed a significant linear correlation between TNF-alpha release and NO2- production. Antiserum to TNF-alpha suppressed TNF-alpha release, NO2- production, and amebicidal activity by 93, 53, and 86%, respectively. L-NMMA diminished NO2- production by 74% and macrophage amebicidal activity by 83% but had no effect on TNF-alpha release. Quantification by Northern (RNA) blot analyses demonstrated that IFN-gamma in combination with TNF-alpha or LPS increased markedly the accumulation of mac-NOS and TNF-alpha mRNAs in a time-dependent manner with a concomitant increase in NO and TNF-alpha production. Peak induction of mac-NOS occurred after 24 h, whereas TNF-alpha mRNA was rapidly expressed after 4 h and remained stable for 48 h. Taken together, these data argue that TNF-alpha augments NO-dependent macrophage cytotoxicity against E. histolytica via elevated levels of mac-NOS mRNA expression which may be associated with the accumulation of TNF-alpha mRNA.

Early detection of unilateral occlusion of duplicated müllerian ducts: the use of serial pelvic sonography for girls with renal agenesis

For early detection of unilateral occlusion of duplicated müllerian ducts, serial pelvic sonography was performed in 215 girls with known renal agenesis, especially following menarche, during the last 6 years. To date, 16 girls with unilateral occlusion of duplicated müllerian ducts were detected. We stress the value of this modality, which can lead to a prompt diagnosis, and allow for early and appropriate surgical intervention.

Ethical reasoning concerning the feeding of severely demented patients: an international perspective

Structured interviews were held with 149 registered nurses in seven countries in America, Asia, Australia and Europe concerning the feeding of severely demented patients who do not accept food. The most common reasons for nurses being willing to change their decision to feed or not to feed were an order from the medical head, a request from the patient's husband and/or the staff meeting. There was a connection between the willingness to feed and the ranking of ethical principles. Nurses who were most prone to feed the patient most often gave a high rank to the ethical principle of sanctity of life, while those who primarily chose not to feed the patient gave a high rank to the ethical principle of autonomy. All nurses stressed the ethical principle of beneficence.

A new crystal form of abrin-a from the seeds of Abrus precatorius

A new crystal form of abrin-a from the seeds of Abrus precatorius has been obtained by vapor diffusion method. The abrin-a crystals belong to monoclinic space group P2(1) with cell dimensions a = 84.58 A, b = 73.07 A, c = 48.23 A, beta = 96.20 degrees. An asymmetric unit contains one protein molecule of molecular weight 65 kDa and has a solvent content of approximately 46%.

Cloning and expression of three abrin A-chains and their mutants derived by site-specific mutagenesis in Escherichia coli

DNAs encoding of three abrin A-chains were obtained from the cDNA library of Abrus precatorius by polymerase chain reaction and ligated into the expression vector, pGEX-2T. The mature A-chains of abrins a, b and d have been expressed in the cytoplasm of Escherichia coli, and the yield of the soluble recombinant proteins was 7 mg/l induced culture. Three recombinant abrin A-chains were purified to be homogeneity and their N-glycosidase ability to inhibit protein biosynthesis in a cell-free system and to depurinate 28S rRNA in rat liver ribosomes was demonstrated in vitro. The recombinant abrin-a A-chain had the highest N-glycosidase activity among three recombinant abrin A-chains while the recombinant abrin-b A-chain, the least. Three mutants, glutamic-acid-to-alanine replacement (E164A), arginine to leucine (R167L) or double mutation (E164A and R167L) were constructed and expressed. The protein-biosynthesis-inhibitory activity of mutant (E164A), mutant (R167L) and the double mutant was found to be 25-fold, 625-fold and 1250-fold lower than that of wild type, respectively. The results indicated that Arg167 was essential for abrin toxin A-chain catalysis.

Stimulatory effects of bombesin-like peptides on hypothalamic arcuate neurons in rat brain slices

The effects of bombesin, gastrin-releasing peptide, neuromedin C, ranatensin, and neuromedin B on hypothalamic arcuate neurons were tested in this study using extracellular single-unit recording in fresh brain tissue slices. Adult ovariectomized Sprague-Dawley rats were used for preparation of brain slices. All bombesin-like peptides in pmol ranges exhibited potent stimulatory effects on the firing of arcuate neurons, i.e., gastrin-releasing peptide stimulated 90.9% (n = 22), bombesin 78.0% (n = 41), neuromedin C 63.2% (n = 19), ranatensin 58.0% (n = 22), and neuromedin B 50.0% (n = 6) of arcuate neurons tested. Pretreatments with either [Leu13-psi(CH2NH)-Leu14]-bombesin or [D-Phe6,Des-Met14]-bombesin6-14 ethylamide, two bombesin antagonists, significantly blocked most of the actions of bombesin-like peptides tested. The present results further support the notion that bombesin-like peptides may play a significant role in the arcuate nucleus.