Stimulation of inositol phosphate production and GTPase activity by compound 48/80 in rat peritoneal mast cells

Phospholipase C activity, GTPase activity and cytosolic-free calcium concentration in mast cells were stimulated by compound 48/80. Accumulation of inositol phosphates in rat mast cells was stimulated by guanosine 5'-[gamma-thio]-triphosphate. Guanosine 5'-[gamma-thio]triphosphate, however, exhibited no effect upon the purified phospholipase C activity and upon phospholipase C in the mast cell homogenate. The stimulatory effect of compound 48/80 upon phospholipase C activity of intact mast cells was observed to have been well correlated with that on GTPase activity of mast cell homogenate. Compound 48/80 exhibited no effect upon the binding of radioactive guanosine 5'-[gamma-thio]triphosphate to mast cell homogenate. Phospholipase C activity was verified by the above results to become affected by compound 48/80 through guanine nucleotide-binding regulatory protein.

Neonatal hearing impairment complicated by neonatal pneumonia. Application of auditory evoked potentials in neonatology

A group of 433 neonates with pneumonia were studied through the monitoring of audiology on the basis of epidemiology in perineonatal hearing impairment and applied auditory evoked potentials. The results showed that 29 cases had a threshold of more than 30 dBnHL in primary auditory brainstem response test (6.7%), and 19 cases with threshold, more than 40 dBnHL in primary 40Hz-auditory event related potential (40Hz-AERP) test (4.4%). The follow-up between the 3rd and 12th month after the initial test demonstrated that 12 cases had hearing impairment to various degrees.

Acute fatty liver of pregnancy: a report of two cases

In the past two years, two women with acute fatty liver of pregnancy have presented at this hospital. Both patients survived, but their babies died; published rates for both mother and fetus are up to 85% mortality with this condition. Both patients presented with symptoms and signs of impending hepatic failure including jaundice, elevated aminotransferases, leukocytosis, hepatic encephalopathy and disseminated intravascular coagulation during the third trimester. Diagnosis was established by liver biopsy in both cases. The unusual good outcome for both women can be attributed to early recognition and prompt delivery, once diagnosis was considered.

Multifocal thoracic actinomycosis simulating lymphoma

Thoracic actinomycosis is rare in the pediatric age group. We report the unusual case of a 10-year-old girl who presented with prolonged fever and weight loss with a neck mass and multiple pulmonary nodules resembling lymphoma. Open lung biopsy confirmed the diagnosis of actinomycosis and the symptoms and signs improved after treatment with cephalosporin. The pathogenesis and radiographic manifestations are briefly discussed.

Expression, regulation and function of human Fc epsilon RII (CD23) antigen

CD23, also known as the low affinity receptor for IgE (Fc epsilon RII), belongs to a novel superfamily of type-II integral membrane proteins. Fc epsilon RII expression was originally described on B cells but subsequent studies showed that CD23 is expressed on a variety of hematopoietic cells and is regulated by several cytokines (i.e., interleukin-4, interferons) in a tissue-specific manner. In some pathological conditions such as B-chronic lymphocytic leukemia, the CD23 gene is abnormally regulated resulting in CD23 overexpression. CD23 is not only an IgE receptor but also a membrane-bound precursor of soluble molecules that still bind IgE (sCD23 or IgE-binding factors). The functions of membrane CD23 are IgE-dependent and vary according to the cell types on which it is expressed. In contrast, sCD23, in addition to being an IgE regulatory molecule, displays multiple cytokine activities that are IgE-independent.

Differential effect of transforming growth factor beta on the synthesis of Th1- and Th2-like lymphokines by human T lymphocytes

(TGF)-beta is a pluripotent cytokine exerting differential effects on distinct components of the immune response. The present report, based on lymphokine determination in culture supernatants and Northern blot analysis of lymphokine mRNA, demonstrates that TGF-beta 2 markedly inhibits interleukin (IL)-4 and IL-5 synthesis by polyclonally activated human T cells in the absence of any significant effect on (IFN)-gamma, lymphotoxin or IL-2, suggesting a modulatory effect of TGF-beta 2 on the interferon Th1/Th2) balance of immune responses. The inhibitory effect of TGF-beta on IFN-gamma production by unfractionated peripheral blood mononuclear cells is likely to reflect the blunting of natural killer cell activation by TGF-beta.

Kinetic analysis of duck epsilon-crystallin with L-lactate dehydrogenase activity: determination of kinetic constants and comparison of substrate specificity

A systematic analysis of the kinetic properties of duck lens epsilon-crystallin with lactate dehydrogenase [LDH, (E.C. 1.1.1.27)] activity was carried out by employing some 19 different alpha-keto acids as substrates for this NADH-dependent LDH-catalyzed reaction. The steady-state Michaelis and catalytic constants (Km, kcat) were determined for a broad range of organic compounds. The results provide important insights regarding the binding and affinity of substrates to active sites of this enzyme crystallin and indicate a great potential for the application of the stable epsilon-crystallin as a catalyst to the synthesis of some important chiral alpha-hydroxyacids in a convenient and efficient way. It is also demonstrated for the first time that in addition to the enzymatic activity of lactate dehydrogenase, duck epsilon-crystallin also possesses the enzymatic activity of malate dehydrogenase.

Detection of methicillin-resistant staphylococci by using the polymerase chain reaction

A polymerase chain reaction (PCR)-based test was developed for the detection of mecA in staphylococci. To facilitate this process, a rapid cell lysis procedure was established for the release of DNA from staphylococcal strains. Primers based on the DNA sequence of the mecA gene from Staphylococcus aureus were used in PCRs to screen for the presence of this gene in a total of 98 staphylococcal isolates. Fifty-one isolates were mecA positive (17 S. aureus strains and 34 coagulase-negative staphylococci including S. epidermidis, S. haemolyticus, and S. simulans). Results obtained with PCRs were generally consistent with those of standard microbiological assays. PCRs designed to detect the femA gene (factor essential for methicillin resistance) revealed the presence of the gene in all S. aureus strains examined regardless of the susceptibility profiles of the strains to methicillin. In contrast, femA could not be detected in coagulase-negative staphylococci by PCR with the same primers. Low-stringency hybridization suggested the presence of a gene structurally related to femA in S. epidermidis and other coagulase-negative staphylococci examined.

Facile synthesis of chiral 2-hydroxy acids catalyzed by a stable duck epsilon-crystallin with endogenous L-lactate dehydrogenase activity

Duck epsilon-crystallin, an abundant structural protein in lenses of some avian species, was shown to possess a genuine and stable L-lactate dehydrogenase (L-LDH; EC 1.1.1.27) activity suitable for the application to enzyme technology as a catalyst for the synthesis of chiral alpha-hydroxy acids. Two pharmaceutically important intermediates, 2-hydroxy acids (S)-2-hydroxybutanoic acid (S)-2-hydroxypentanoic acid have been synthesized in high yields and optical purity utilizing an in situ NADH regeneration system of duck epsilon-crystallin coupled with formate/formate dehydrogenase. This enzyme system is also shown to offer some advantages over the conventional L-LDH sources from several mammalian species.

Cloning and characterization of a gene required for the secretion of extracellular enzymes across the outer membrane by Xanthomonas campestris pv. campestris

Nonpathogenic mutants of Xanthomonas campestris pv. campestris, generated from transposon mutagenesis, accumulated extracellular polygalacturonate lyase, alpha-amylase, and endoglucanase in the periplasm. The transposon Tn5 was introduced by a mobilizable, suicidal plasmid, pSUP2021 or pEYDG1. Genomic banks of wild-type X. campestris pv. campestris, constructed on the broad-host-range, mobilizable cosmid pLAFR1 or pLAFR3, were conjugated with one of the mutants, designated XC1708. Recombinant plasmids isolated by their ability to complement XC1708 can be classified into two categories. One, represented by pLASC3, can complement some mutants, whereas the other, represented by a single plasmid, pLAHH2, can complement all of the other mutants. Restriction mapping showed that the two recombinant plasmids shared an EcoRI fragment of 8.9 kb. Results from subcloning, deletion mapping, and mini-Mu insertional mutation of the 8.9-kb EcoRI fragment suggested that a 4.2-kb fragment was sufficient to complement the mutant XC1708. Sequence analysis of this 4.2-kb fragment revealed three consecutive open reading frames (ORFs), ORF1, ORF2, and ORF3. Hybridization experiments showed that Tn5 in the genome of XC1708 and other mutants complemented by pLASC3 was located in ORF3, which could code for a protein of 83.5 kDa. A signal peptidase II processing site was identified at the N terminus of the predicted amino acid sequence. Sequence homology of 51% was observed between the amino acid sequences predicted from ORF3 and the pulD gene of Klebsiella species.

Modulation of human IgE synthesis by transforming growth factor-beta

Exogenous transforming growth factor-beta 2 (TGF-beta 2) markedly inhibits the interleukin 4 (IL4)-stimulated synthesis of human IgE in three models where the B cell co-stimulation signals are contact dependent. This concerns T cell-dependent IgE production by (i) unfractionated peripheral blood mononuclear cells (PMBC) cultured with IL4 and (ii) highly purified B cells cocultured with irradiated EL4 thymoma cells in the presence of IL4 and phorbol myristate acetate, as well as monocyte-dependent IgE production by rigorously T cell-depleted PBMC cultured with IL4 and hydrocortisone. The suppression is not isotype specific. TGF-beta exerts its effect by inhibiting the proliferation of B cells and perhaps also the differentiation of proliferating B cells. However, at a later stage of differentiation, IgE B cells are refractory to the inhibitory effect of TGF-beta, as shown by the slight but significant increase of the spontaneous secretion of IgE by PBMC of atopic patients. This enhancement is due to the suppression of endogenous interferon-gamma production. Most interestingly the synthesis of IgE by highly purified B cells costimulated with IL4 and Epstein-Barr virus is unaffected by TGF-beta. It is concluded that TGF-beta mainly acts by inhibiting IL4-supported B cell proliferation; however, its effects depend upon the B cell costimulation signals that are required together with IL4 for the induction of IgE synthesis.

Construction of a water-soluble form of penicillin-binding protein 2a from a methicillin-resistant Staphylococcus aureus isolate

The mecA gene from methicillin-resistant Staphylococcus aureus 27r, which encodes the membrane-bound penicillin-binding protein 2a (PBP 2a), was cloned, sequenced, and expressed in Escherichia coli. PBP 2a is the major factor that mediates methicillin resistance in staphylococci. The DNA sequence of the mecA gene from strain 27r was greater than 99% identical to the DNA sequence of other S. aureus mecA genes and the mecA gene from Staphylococcus epidermidis. Analysis of the deduced amino acid sequence of PBP 2a from strain 27r revealed a hydrophobic region at the amino terminus that possessed characteristics of an uncleaved signal peptide such as those found in type II integral membrane proteins. Site-specific mutagenesis was used to modify the strain 27r mecA gene to permit removal of the region encoding the putative transmembrane region (amino acids 2 to 22). When it was expressed in E. coli, the modified mecA gene from strain 27r encoded a water-soluble form of PBP 2a that was detectable in the cytoplasm of transformants. The water-soluble form of PBP 2a protein from S. aureus 27r retained the same binding efficiency for beta-lactam antibiotics as the unmodified membrane-bound PBP 2a from S. aureus 27r.

Specific peptide-bond cleavage by microwave irradiation in weak acid solution

A rapid and selective peptide-bond cleavage in weak acid, induced by microwave irradiation, has been developed. The specific cleavage sites of peptide bonds located only at the carboxyl- and amino-terminal ends of aspartyl residues along the peptide chain. A systematic study including the time course for the cleavage of various aspartyl-containing peptides, the effect of the acidity of the reaction solution on the completeness of peptide-bond cleavage, and the relationship between the power of microwave irradiation and the reaction time of cleavage are studied.

Profile of nonnurse college graduates enrolled in accelerated baccalaureate nursing programs

Accelerated baccalaureate nursing programs have been found to be a feasible way of increasing the supply of professional nurses at a time of declining enrollments in schools of nursing. This study explored the sociodemographic characteristics of nonnurse college graduates who pursue baccalaureate degrees in nursing. Students' gender, age, income, previous education, occupation, work setting, and nursing experience were studied. Data were collected from 166 nursing students (71 per cent) from the 10 (100 per cent) schools of nursing in the United States that offered the accelerated baccalaureate nursing programs in 1988. The findings of this study have important policy implications for nursing administrators, educators, and recruiters for planning of this type of nursing education program.

Glucocorticoids suppress the production of interleukin 4 by human lymphocytes

Given that glucocorticoids (GCS) were reported to increase the production of interleukin 4 (IL4) by mouse T cells and that GCS are widely used to treat allergic diseases it was important to examine the effect of these agents on IL4 production by human lymphocytes. We here demonstrate that the production of IL4 by human lymphocytes is markedly inhibited by small concentrations of hydrocortisone. The suppression is observed at the protein and at the mRNA levels and it is not secondary to the GCS-induced inhibition of IL2 production.

Changes in plasma active and inactive renin and prekallikrein during hemodialysis

To investigate the physiologic role of plasma inactive renin and its relationship to plasma kallikrein, we measured the changes in plasma active renin, inactive renin and prekallikrein levels in 14 uremic patients before and after hemodialysis. Blood was collected before, during and after hemodialysis, and prior to the next dialysis session. Plasma active renin was measured by radioimmunoassay of generated angiotensin I after addition of an exogenous substrate. Plasma inactive renin was activated by trypsin. Plasma prekallikrein was measured by the kallikrein-like activity on synthetic substrate S-2302 after activation of prekallikrein. The results showed that there was no change in blood pressure before, during or after dialysis, whereas the change in body weight after dialysis was significant. There was also no significant difference in the plasma active renin, inactive renin and prekallikrein levels for any of the collection periods. Plasma active renin was significantly correlated with inactive renin. The correlation between the active renin/total renin ratio and the plasma prekallikrein level was also not significant. These results suggest that in uremic patients undergoing chronic hemodialysis, the response of the renin system to acute plasma volume change is blunted. These data only provide evidence that plasma active renin is linked with inactive renin, but provide no evidence to support the idea that plasma inactive renin is a precursor of active renin or that plasma kallikrein is related to activation of inactive renin in vivo.

Synthesis and antimicrobial evaluation of dirithromycin (AS-E 136; LY237216), a new macrolide antibiotic derived from erythromycin

Dirithromycin is a 9-N-11-O-oxazine derivative which is formed by condensation of 9(S)-erythromycylamine with 2-(2-methoxyethoxy)acetaldehyde. Dirithromycin is hydrolyzed, either under acidic conditions or in vivo, to its major active metabolite, 9(S)-erythromycylamine. The antimicrobial spectrum of dirithromycin is similar to that of erythromycin; both antibiotics are active against gram-positive bacteria, Legionella spp., Helicobacter pylori, and Chlamydia trachomatis. Comparable results were obtained for each antibiotic in MIC and MBC determinations and in the potential development of resistance in vitro. The effects of human serum, bacterial growth media, test methodology, and inoculum size on MICs were similar for each antibiotic. In standard mouse protection studies, dirithromycin was more efficacious than erythromycin against experimental infections after subcutaneous administration of antibiotic. These results were consistent with pharmacokinetic studies in rodents, which showed that dirithromycin gave more persistent concentrations of antibiotic in serum and tissues than were achieved with erythromycin. These studies indicate that dirithromycin possesses antimicrobial activity comparable to that of erythromycin in vitro but is more active than erythromycin in vivo, which may be attributable to the persistence of antimicrobial activity in the tissue(s) of the test animals.

Protein Synthesis in Isolated Mitochondria of Rice (Oryza sativa L.) Seedlings

For studies of in organello mitochondrial protein synthesis in rice, Oryza sativa L., conventional surface-sterilization procedures were demonstrated to be ineffective. Because of the over-whelmingly efficient [(35)S]methionine utilization by contaminating bacteria, even "essentially bacteria-free" rice mitochondria were shown to be unsuitable for the study of in organello protein synthesis. We developed a procedure to obtain a bacteria-free preparation of rice mitochondria. Such mitochondria favored a membrane-dependent ATP-generating system over an external ATP-generating system as the energy supplement for in organello protein synthesis. Two distinct classes of [(35)S]methionine-labeled, cycloheximide-insensitive products were detected: an electrophoretically unresolved population and a set of some 22 to 27 discrete polypeptide species, each with a characteristic electrophoretic mobility and relative abundance.

Glucocorticoids increase the synthesis of immunoglobulin E by interleukin 4-stimulated human lymphocytes

This study indicates that hydrocortisone (HC) markedly increases the synthesis of immunoglobulin E (IgE) by interleukin 4 (IL-4)-stimulated human lymphocytes. The effect is glucocorticoid specific and is obtained with low concentrations of HC (0.1-10 microM). In both the early and the late phase of the IL-4-induced response HC exerts its effects which are respectively IL-4 dependent and IL-4 independent. The IgE potentiation cannot be explained by the inhibition of interferon-gamma (IFN-gamma) production since it is observed in the absence of endogenous secretion of IFN-gamma. HC inhibits the production of IgE-binding factors (soluble CD23) and the expression of the low-affinity receptor for IgE, also known as the (Fc epsilon RII) CD23 antigen; however, the residual expression of Fc epsilon RII by IL-4- and HC-treated peripheral blood mononuclear cells (PBMCs) is important since the IgE response of these cells is markedly inhibited by anti-CD23 monoclonal antibody. HC acts mainly by amplifying the cellular interactions between monocytes and lymphocytes; indeed, HC has no effect on monocyte-depleted PBMCs, and moreover, monocytes cannot be replaced by soluble factors. Most importantly, T cells are not required for the induction of IgE synthesis by costimulation with IL-4 and HC. However, the IgE response of rigorously T cell-depleted PBMCs may be further increased by the addition of T cells. Further analysis of the permissive effect of HC on the synthesis of IgE by T cell-depleted PBMCs suggests that HC acts in synergy with IL-4 to trigger the activation and the differentiation of B cells into IgE-producing cells.

Fetal tissue grafts for cerebellar atrophy

It has been shown in a rat model that surgical injury to the right cerebellum with resultant ataxia can be corrected by implantation of embryonic cerebellar tissue into the injured cerebellum. Histological examinations of the cerebellar tissue revealed that mitoses of Purkinje cells of the implanted group were increased substantially over the control group's. The surgically induced ataxia resolved more rapidly in the cerebellar implant group than the control group. Based on this experimental data, a similar technique was applied in 6 patients with severe hereditary cerebellar degenerative ataxia. The preliminary results in these 6 surgically implanted patients with heredity degenerative cerebellar disease show 2 with marked improvement, 3 with moderate improvement and 1 with improvement for 2 months followed by mild deterioration but still better than presurgery. We also studied immunological markers in the blood and CSF in an attempt to determine whether rejection of implanted tissue occurs.

Complexity in evolved regulatory variation for alcohol dehydrogenase genes in Hawaiian Drosophila

The alcohol dehydrogenase gene (Adh gene) of Drosophila affinidisjuncta is expressed at a higher level in the larval midgut and Malpighian tubules than the homologous gene from Drosophila hawaiiensis. This study analyzed the cis-acting sequences responsible for these regulatory differences in larval tissues of Drosophila melanogaster transformants. A series of 10 chimeric and deleted Adh genes was introduced into the germ line of D. melanogaster, and tissue-specific expression levels were quantified by gel electrophoresis of tissue extracts. Sequences in the upstream region of the two genes had the strongest influence on enzyme production in the midgut and Malpighian tubules. Other sequence elements also showed effects, some of which were tissue specific. Most gene fragments displayed context-dependent effects, thus supporting the proposed model of polygenic regulation of Adh gene expression.