Evaluation of swallowing safety with fiberoptic endoscope: comparison with videofluoroscopic technique

Videofluoroscopy has long been viewed as the "gold standard" of swallowing examination for the comprehensive information it provides. However, it is not very efficient and accessible in some practical situations. In this study, we tried to use a modified technique of fiberoptic endoscopic examination of swallowing (FEES) in evaluating dysphagic patients. For each examination, a spoonful of pudding and dyed water were fed in sequence three times. The pharyngeal swallowing events were observed with fiberscope panoramically and videotaped. Twenty-eight chronic dysphagic patients underwent both videofluoroscopy and FEES in 2 weeks. Comparison of the results revealed that disagreements in premature oral leakage to the pharynx, pharyngeal stasis, laryngeal penetration, aspiration, effective cough reflex, and velopharyngeal incompetence were 39.3%, 10.7%, 14.3%, 14.3%, 39.3%, and 32.1%, respectively. FEES was found to be more sensitive in detecting these risky features of swallowing, except with respect to premature leakage. Possible causes of the discrepant results are discussed, and the limitation of videofluoroscopy in practical usage is discussed. FEES is conclusively a safer, more efficient, and sensitive method than videofluoroscopy in evaluating swallowing safety.

Palytoxin-induced single-channel currents from the sodium pump synthesized by in vitro expression

Palytoxin, the most potent animal toxin, is proposed to convert Na+/K(+)-ATPase into a cation-selective ion channel. Because of the ubiquity of pumps and channels in the living tissues used to study its mechanism of action, it is difficult to rule out that another site may be involved. In order to show that palytoxin selectively acts on Na+/K(+)-ATPase, two entirely in vitro methods were employed: (1) a cell-free expression system to synthesize the rat alpha 3 and beta 1 subunit proteins, and (2) single-channel recording of the synthetic Na+/K(+)-ATPase reconstituted in a planar lipid bilayer. Upon addition of palytoxin, single-channel currents were induced which had a conductance of 10 pS, in agreement with previous studies. In control experiments, when the cDNAs for Na+/K(+)-ATPase subunits were omitted, no single-channel currents were induced with palytoxin. Thus, the results show unambiguously that the Na+/ K(+)-ATPase is the site of action for palytoxin. Because palytoxin turns the Na+/K(+)-ATPase into a channel which can be detected by the exquisitely sensitive single-channel recording technique, the present results are the first to demonstrate the activity of in vitro synthesized Na+/K(+)-ATPase.

Design and preparation of a multimeric self-cleaving hammerhead ribozyme

The activity of a ribozyme can be impaired by additional sequences at the 5' and 3' termini of the catalytic sequence. To approach this problem, a system was designed that minimizes sequences upstream and downstream from active regions of a hammerhead ribozyme and allows delivery of a large number of active molecules. A self-cleavable multimeric molecule was prepared by placing a ribozyme target sequence (derived from the core region of the hepatitis B virus [HBV]) upstream and downstream from the catalytic sequence. This construct was cloned in tandem into in vitro expression vectors. 32P-UTP-labeled transcripts of the multimeric construct, as well as non-self-cleaved monomeric ribozyme controls, and substrate were synthesized. The multimeric ribozyme molecule efficiently self-cleaved to release monomeric ribozymes lacking any extra upstream and downstream sequences. In addition, monomers were substantially more active against the HBV target RNA than the non-self-cleavable ribozymes. Up to 80% degradation of the target RNA was achieved by a tenfold molar excess of a pentameric construct. We conclude that ribozymes can be produced as a multimeric tandem of self-cleavable molecules, the monomers of which are more active than monomeric ribozymes and highly efficient in cleavage of target transcripts.

Molecular cloning and nucleotide sequencing of bioF (7-keto-8-amino pelargonic acid synthetase), bioC and bioD (dethiobiotin synthetase) genes of Erwinia herbicola

The biotin operon of Erwinia herbicola Eho 10 was cloned and characterized by complementation of E. coli biotin mutants. The operon was found to contain five genes arranged in the order, bioABFCD. The nucleotide sequences of bioF (7-keto-8-aminopelargonic acid synthetase), bioC and bioD (dethiobiotin synthetase) were determined and analyzed. The nucleotide sequences and deduced amino acid sequences of bioFCD were compared with the corresponding sequences from Escherichia coli, Bacillus sphaericus, Serratia marcescens and Brevibacterium flavum.

Response of amoeboid and ramified microglial cells to lipopolysaccharide injections in postnatal rats--a lectin and ultrastructural study

The present study describes the response of amoeboid and ramified microglial cells in the corpus callosum to intraperitoneal lipopolysaccharide injections in postnatal rats as examined by lectin histochemical staining and electron microscopy. In 1 day old rats receiving endotoxin injections and sacrificed at various time intervals, the lectin labelling of amoeboid/ramified microglia was greatly enhanced. The increased labelling persisted in some ramified microglia in rats killed at 14 and 21 days of age; otherwise in normal or control animals of the corresponding stages, the same cells were very weakly stained. In rats killed at 2 days of age after intraperitoneal lipopolysaccharide injection, the number of microglia appeared to increase, but this was reduced at 7 days of age. The lectin-labelled amoeboid/ramified microglia were frequently seen adherent to the outer walls of the callosal blood vessels where infiltrated lymphocytes were also observed. Ultrastructurally, some lectin-labelled microglial cells underwent degeneration and were engulfed by other lectin-positive cells. After endotoxin injections, microglial cells, notably the amoeboid form, showed extensive ruffling at their cell membrane, massive accumulation of lysosomes and increased staining of lectin at their Golgi apparatus. A similar lectin labelling pattern was also observed in ramified microglia of lipopolysaccharide-injected rats. It is concluded that both amoeboid and ramified microglial cells in postnatal rats responded to endotoxin injections as reflected by their enhanced lectin labelling at the surface membrane, lysosomes and Golgi apparatus. It is suggested that such changes may be involved in synthesis and/or modification of galactosyl glycoconjugates probably for the increased production of membranous glycoproteins or lysosomal enzymes.

Enhanced high-level Petri nets with multiple colors for knowledge verification/validation of rule-based expert systems

Exploring the properties of rule-based expert systems through Petri net models has received a lot of attention. Traditional Petri nets provide a straightforward but inadequate method for knowledge verification/validation of rule-based expert systems. We propose an enhanced high-level Petri net model in which variables and negative information can be represented and processed properly. Rule inference is modeled exactly and some important aspects in rule-based systems (RBSs), such as conservation of facts, refraction, and closed-world assumption, are considered in this model. With the coloring scheme proposed in this paper, the tasks involved in checking the logic structure and output correctness of an RES are formally investigated. We focus on the detection of redundancy, conflicts, cycles, unnecessary conditions, dead ends, and unreachable goals in an RES. These knowledge verification/validation (KVV) tasks are formulated as the reachability problem and improper knowledge can be detected by solving a set of equations with respect to multiple colors. The complexity of our method is discussed and a comparison of our model with other Petri net models is presented.

Sequencing and immunochemical characterization of the American cockroach per a 3 (Cr-PI) isoallergenic variants

Two additional members of the American cockroach (Periplaneta americana) Per a 3 (Cr-PI) allergen, C13 and C28, were isolated and sequenced. They encoded proteins of 470 and 393 amino acids with two and no potential N-glycosylation sites, respectively. The molecular weights for C13 and C28 cloned proteins are 56,200 and 46,7000, with PI values of 7.06 and 6.54. C13 and C28 display 95.4% identity with several overlapping predicted central antigenic determinants. Both allergens were also found to have a 95% sequence homology with previously cloned C20 and share similar antigenic determinants, as defined by the structural prediction and ELISA analysis. However, the recombinant C13 and C28 allergens showed 26.3 and 94.7% skin reactivities on asthmatic patients while C20 elicited 47.4%. While no sequence similarity was found to other known allergens, these two aromatic amino acid-rich allergens were highly related to insect hemolymph proteins (28.7-36.5%), as with C20 cloned protein. Results suggest that these two are isoallergenic variants of C20. Sequence variations among isoforms, resulting a significant difference in skin reactivities, will be useful in elucidating the allergenic determinants.

Intracellular cleavage of hepatitis C virus RNA and inhibition of viral protein translation by hammerhead ribozymes

To determine the effects of hammerhead ribozymes against hepatitis C virus (HCV) RNA on viral protein translation, a luciferase reporter gene vector, pCMV/T7-NCRCdelta-luc, was constructed containing the 5'-noncoding region (5'-NCR) and part of the core region of HCV. Four ribozymes, Rz1-Rz4, were designed to cleave at nucleotide positions 136-160, 313-337, 496-520, and 373-388, respectively. Each ribozyme cleaved the target RNA at expected positions under cell-free conditions. Rz2 and Rz4 significantly suppressed translation of NCRCdelta-luc RNA by 71 and 49%, respectively. Translation of control luciferase mRNA lacking viral elements was not affected by the ribozymes. Furthermore, when NCRCdelta-luc RNA and ribozymes were cotransfected into cells, Rz2 and Rz4 significantly suppressed expression by 73 and 56%, respectively. In contrast, cleavage-deficient ribozymes with a point mutation in the hammerhead domain had no significant effect. To determine the effects of endogenously produced ribozymes, eukaryotic expression vectors for Rz2 and Rz4 were constructed. Cotransfection of the vectors with CMV/T7-NCRCdelta-luc showed suppression of luciferase activities to 50 and 61%, respectively. Moreover, transfection of pCMV/T7-NCRCdelta-luc into stable Rz2 and Rz4 producer cells also showed substantial inhibition of luciferase activity. Ribozymes directed against the HCV genome can substantially and specifically inhibit viral gene expression under intracellular conditions.

Peritoneal nitric oxide is a marker of peritonitis in patients on continuous ambulatory peritoneal dialysis

Nitric oxide plays an important role in mediating the inflammatory process. The aim of this study was to evaluate if nitric oxide production was increased during peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD), and the association with the prognosis. The study population comprised 21 patients with 22 episodes of peritonitis. Fifteen patients without peritonitis were controls. Nitrate was measured by HPLC and nitrite by the Griess method, to reflect nitric oxide production. Peritoneal dialysate effluent and plasma were collected from six patients during peritonitis and 1 week after treatment to study changes in dialysate:plasma ratio. In 15 patients, nitrite was measured during peritonitis and every 3 days for 2 weeks or until normalized for evolutional changes. The dialysate:plasma ratios of nitrate and nitrite during peritonitis were reduced 26% and 41.5%, respectively, after 1 week of treatment, indicating the peritoneal production of nitric oxide during peritonitis. In the evolutional study, a 5.1-fold increase of peak nitrite levels in bacterial peritonitis (n = 13) and a 2.5-fold increase in fungal peritonitis (n = 3) were observed compared to controls. Nitrite gradually declined to control levels (9.3 +/- 7.2 days) after effective antibiotic treatment, but took longer than to normalize leukocyte count in the peritoneal dialysate effluent (3.9 +/- 1.9 days). In four patients with refractory peritonitis (Candida infection in three, Acinetobacter infection in one), the nitrite levels remained elevated 2-fold despite treatment, and the catheters were removed. It is concluded that nitrite levels in peritoneal dialysate effluent may serve as a marker to assess treatment efficacy in CAPD patients with peritonitis.

Delivery of a hammerhead ribozyme specifically down-regulates the production of fibrillin-1 by cultured dermal fibroblasts

The hammerhead ribozyme is a small catalytic RNA molecule. Potential hammerhead ribozymes that possess a catalytic domain and flanking sequence complementary to a target mRNA can cleave in trans at a putative cleavage site within the target molecule. We have investigated the potential of hammerhead ribozymes to down-regulate the product of the fibrillin-1 gene (FBN1). Fibrillin is a 347 kDa glycoprotein that is a major constituent of the elastin-associated microfibrils. Mutations in the FBN1 gene are responsible for Marfan syndrome (MFS), a common systemic disorder of the connective tissue. Many FBN1 mutations responsible for MFS appear to act in a dominant-negative fashion, raising the possibility that reduction of the amount of product from the mutant FBN1 allele might be a valid therapeutic approach for MFS. A trans-acting hammerhead ribozyme (FBN1-RZ1) targeted to the 5' end of the human FBN1 mRNA has been designed and synthesized, and shown to cleave its target efficiently in vitro. FBN1-RZ1 cleavage is magnesium dependent and efficient at both 37 and 50 degrees C. Delivery of the FBN1-RZ1 ribozyme into cultured dermal fibroblasts, by receptor-mediated endocytosis of a ribozyme-transferrin-polylysine complex, specifically reduces both cellular FBN1 mRNA and the deposition of fibrillin in the extracellular matrix. These results suggest that the use of hammerhead ribozymes is a valid approach to the study of fibrillin gene expression and possibly to the development of a therapeutic approach to MFS.

Immunohistochemical study of amoeboid microglial cells in fetal rat brain

The present study examined the expression of different antigens in amoeboid microglial cells (AMC) in fetal rat brain extending from 12 to 20 d postconception (E12-E20) using a panel of monoclonal antibodies which recognised the major histocompatibility complex (MHC) class I (OX-18) and class II (OX-6) antigens, leucocyte common antigen (OX-1), CD4 receptor (OX-35), complement type 3 receptor (OX-42) or macrophage antigens of unknown function (ED1 and ED2). Of the above-mentioned antigens, ED1 and ED2-labelled AMC were observed in the neuroepithelia as early as embryonic day 12 (E12); other antigens were not detected at this stage. At E14, except for MHC class I antigen, all other antigens were expressed by AMC distributed predominantly in the developing white matter. At E16, AMC in the intermediate zone lateral to the striatum were endowed with all the above-mentioned antigens including MHC class I. At E18, the immunoreactivities of AMC stained with OX-6, OX-18, OX-35 and OX-42 antigens were noticeably reduced when compared with those cells at E16. At E20, amoeboid microglial cells exhibited full complement of antigen expression similar to those cells at E16; some of the labelled cells emitted a variable number of cytoplasmic processes. It is suggested that the successive and differential expression of various macrophage related antigens on AMC in fetal brain is related to the specific requirement of local environment in different stages of development.

The association of periventricular echodensity with cerebral palsy in preterm infants

The purpose of this study was to investigate the risk factors of development of cerebral palsy (CP) in preterm infants who had periventricular echogenic abnormalities with or without cyst formation. During a period of 66 months, 332 newborns of 34 weeks gestation or less born at our hospital received serial brain ultrasound scans. Sixty-six of the 332 infants, 36 males and 30 females, were detected increased periventricular echodensity (PVE) during admission period. Subsequently, serial brain ultrasound scans were done for the 66 preterm infants at our follow-up clinic. Their neurodevelopment outcomes were then followed up for 10-48 months. The degree of periventricular echodensity (PVE) was graded as mild; or moderate to severe, according to the extent of the echodensity. Periventricular echodensity with cyst formation was classified by the size of the cyst at its widest diameter as either large (3 mm or multiple) or small (< 3 mm) in the parasagittal image. Eighteen of 66 (27.3%) infants developed cerebral palsy (CP). Infants with PVE with large cystic formation were at significantly higher risk for development of cerebral palsy (P < 0.005). Nine of 16 (56.3%) patients in the CP group had a longer duration of PVE than the non-CP group (8 of 46 patients: 17.4%) (p < 0.005). It is concluded that large cystic periventricular echodensity and long duration of PVE are associated with later development of cerebral palsy.

Sympathetic effects on the steroidogenesis and proliferation of adrenocortical cells in vitro

Recent evidence supports the hypothesis that sympathetic neurons play a significant role in the regulation of adrenocortical cell proliferation and steroidogenesis. Co-cultures of rat adrenocortical and sympathetic ganglion cells have been established to study sympatho-adrenal interactions. In these studies we have compared differentiation, growth and secretion of adrenocortical cells grown in co-culture with those grown alone. Adrenocortical cells were identified using 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) histochemistry or immunocytochemistry; sympathetic neurons were identified using immunocytochemical localization of tyrosine hydroxylase. The sympathetic neurons usually form clusters of 3-10 cells, and extend neurites to adrenocortical cells. Adrenocortical cells continue to proliferate, express 3 beta HSD and sequester lipid droplets. In the co-cultures, the adrenocortical cells are smaller, form larger clusters and show denser 3 beta HSD staining than the adrenocortical cells alone. The presence of the sympathetic neurons enhances adrenocortical cell proliferation as shown by a 2 fold increase in the number of 3 beta HSD(+) cells as well as increased BrdU incorporation after 48 hrs. Steroidogenesis appeared to be enhanced in the presence of sympathetic neurons as demonstrated by 3 beta HSD(+) staining and a 2-fold greater corticosterone and aldosterone secretion. However, when secretion is expressed per number of adrenocortical cells, the rates are comparable, indicating that secretion rate per cell remains unaltered by the presence of neurons. The effects of sympathetic neuron activation on adrenocortical cells remain to be determined.

Isolation and characterization of the Erwinia herbicola bio operon and the sequences of the bioA and bioB genes

The biotin operon of Erwinia herbicola was cloned and characterized. The operon consists of five genes arranged in the order, bioABFCD. The operon is negatively regulated via the interaction of a proposed biotin repressor with an operator sequence that lies between the bioA and bioB genes. The nucleotide sequences of bioA (7,8-diaminopelargonic acid transferase), bioB (biotin synthetase) and the regulatory region were determined and analyzed. The deduced amino acid sequences of bioA and bioB are also aligned with currently available homologs to obtain the UPGMA (unweighted pair group method with arithmetic mean) evolutionary tree.

Detection of k-ras point mutations in codons 12 and 13 in non-small cell lung cancers

Point mutations of the K-ras gene have been reported in a wide variety of human tumors. By using polymerase chain reaction followed by direct DNA sequencing, we screened for point mutations at codons 12 and 13 of the K-ras gene in specimens obtained from fresh frozen tumors in 38 patients with non-small cell lung cancers. Point mutations were detected in two of 38 (5.3%) resected non-small cell lung cancers. Both of them were G to T transversions. One patient was found to have a K-ras codon 13 point mutation (GGC to TGC, gly to cys), while the other had a codon 12 point mutation (GGT to GTT, gly to val). Based on the limited numbers in this study, we found that the frequency of K-ras point mutations in codons 12 and 13 among Asian patients with lung adenocarcinomas was lower than that detected among Caucasian patients.

The Sm binding site targets U7 snRNA to coiled bodies (spheres) of amphibian oocytes

Using cytoplasmic and nuclear injection assays, we show that U7 snRNA constructs are targeted rapidly and specifically to the coiled bodies (spheres) in the germinal vesicle (GV) of the amphibian oocyte, including those coiled bodies attached to the lampbrush chromosomes at the histone gene loci. Because the U7 snRNP is required for removing the 3' end of histone pre-mRNA, we suggest that a major function of coiled bodies is to recruit U7 snRNPs to the histone gene loci, before they associate with the pre-mRNA. Targeting to coiled bodies requires the specific U7 Sm binding site; replacement of the U7 Sm site by that of U2 snRNA reduces this targeting dramatically. No other part of the molecule is required, and the U7 Sm binding site alone is sufficient to direct nuclear import of an unrelated RNA sequence and its specific targeting to coiled bodies. Injected U7 constructs displace the endogenous U7 in the coiled bodies, the amount of injected U7 that ends up in coiled bodies being roughly equal to the amount of endogenous U7 snRNA.

Sequencing analysis of cDNA clones encoding the American cockroach Cr-PI allergens. Homology with insect hemolymph proteins

A previous article described the isolation of several lambdagt22A cDNA clones expressing the American cockroach (Periplaneta americana) Cr-PI allergens recognized by both human atopic IgE antibodies and anti-Cr-PI monoclonal antibodies (Wu, C. H., Lee, M. F., and Liao, S. C.(1995) J. Allergy Clin. Immunol. 96, 352-359). This article presents the nucleotide and deduced amino acid sequences of two cDNA clones encoding major allergens of P. americana. Clones C12 and C20 encode proteins of 685 and 631 amino acids with two potential N-glycosylation sites each. The predicted molecular weights for C12 and C20 cloned proteins are 79,300 and 75, 500 with isoelectric point values of 6.26 and 6.63, which are compatible with the determined sizes (Mr 78,000 and 72,000) and isoelectric point value (6.2) of the Cr-PI allergens of P. americana. A high degree of identity (69.1%), including several overlapped predicted central antigenic determinant residues, was found between two allergens. The anti-fusion protein antibody-based enzyme-linked immunosorbent assay was able to detect crude American cockroach extract, Cr-PI, recombinant proteins, and commercial cockroach extracts, which provides further evidence that two allergens share common antigen determinants. Recombinant allergens of clones C12 and C20 both showed 47.4% skin reactivities on 19 cockroach-sensitive asthmatic patients. Unexpectedly, although no sequence similarity was found to other known allergens, two aromatic amino acid-rich allergens were found to have a striking sequence identity to insect storage proteins (20.1-33.9%), insect juvenile hormone-suppressible proteins (30.9-36.4%), and arthropod hemocyanins (29.7-34.6%). Results suggested that two prominent allergens of P. americana are ancestrally related to these insect hemolymph proteins and represent a new group of proteins in the hemocyanin superfamily. These data will now facilitate epitope-mapping studies, and the recombinant allergens may be valuable for diagnostic and therapeutic purposes.

Quantitative comparison of multiple myeloma tumor contamination in bone marrow harvest and leukapheresis autografts

Autologous transplantation is increasingly being used to treat patients with multiple myeloma (MM). Recently, peripheral blood progenitor cell (PBPC) harvest have been preferred over autologous bone marrow (BM) harvests due to reduced engraftment time, ease of attainment, and presumptive reduction of occult tumor involvement. To resolve this latter assumption quantitatively, we have used the unique immunoglobulin (Ig) heavy chain variable region sequence of the patient's myeloma cell as a marker of clonality. Samples from PBPC collections and 'back-up' BM harvests were obtained from 13 patients with MM and analyzed for tumor contamination using patient-specific oligonucleotide primers and the polymerase chain reaction. As expected, the percentage of tumor cells contaminating the BM harvest (median, 0.74%) was higher than in the PBPC specimens (median, 0.0024%). Because of the increased total number of cells required for PBPC transplantation, the increase in total number of contaminating cells in the BM vs PBPC autografts was less pronounced, (BM:PBPC tumor contamination ratios ranging from 0.9 to > 4500; median, 14). This confirms that in most but not all cases unmanipulated PBPC products are preferable over BM harvests as a method of reducing myeloma autograft tumor contamination.

Inhibition of hepatitis B virus replication by targeted pretreatment of complexed antisense DNA in vitro

We have shown that antisense oligonucleotides can be targeted to hepatitis B virus (HBV)-infected cells, resulting in specific inhibition of viral protein synthesis and replication in vitro. The targeting system was based on the internalization of DNA complexes by highly selective receptors for galactose-terminal glycoproteins, asialoglycoproteins, on the surface of hepatocytes. Our objective in this study was to determine whether antisense DNA could be targeted to hepatocytes to prevent subsequent infection by HBV. A 21-mer phosphorothioate-linked oligo DNA complementary to the HBV polyadenylation signal and 5'-upstream sequences was complexed to a targetable DNA carrier consisting of asialoglycoprotein coupled to polylysine. Pretreatment of Huh7, asialoglycoprotein receptor (+) cells, with antisense complexes before lipofection with an HBV-plasmid at a level of 6.5 x 10(6) copies of plasmid per cell inhibited the amount of newly synthesized, core-associated viral DNA in Huh7 cells to undetectable levels, less than 0.1 pg, as assessed by quantitative polymerase chain reaction (PCR). Hepatitis B viral RNA transcripts were decreased by 60% compared with controls as detected by RNase protection assays, and HBV surface antigen (HBsAg) accumulation was inhibited by 97%. The inhibition lasted for 6 days and was dose dependent. Controls consisting of antisense alone and a random oligo complex showed no significant effect on any of the parameters under identical conditions. We conclude that preexposure of cells to targeted complexed antisense DNA can substantially block viral gene expression and viral replication after transfection of HBV DNA.

Analysis of outpatient referral failures

BACKGROUND

The purpose of this study was to measure the rate at which outpatient referrals failed to be completed, and to analyze predisposing factors for referral failure in the family practice of a medical center.

METHODS

Structured questionnaires were completed by referring physicians whenever a referral was initiated during a 4-month period. On the 60th day after referral, an investigator contacted the referred patients by telephone and also reviewed their charts.

RESULTS

During the 4-month period, 604 referrals (2.28%) were made from 26,476 encounters at the study clinic. Sixty-four patients (10.6%) failed to complete the referral processes within a 60-day period. The most frequent reasons for referral failure were administrative factors, ie, too long a wait (59.4%), and the patient's belief that the referral was not necessary (23.4%). The physician's or patients's opinion of referral necessity, the level of experience of the referring physician, and the method of contact with the consultant all had significant influence on the referral failure rate.

CONCLUSIONS

Improving administrative efficiency, enhancing communication between physicians and between physicians and patients, assessing the willingness of patients to follow through on a referral, and the method used to initiate the referral by the physician may reduce the referral failure rate.

Circulating soluble intercellular adhesion molecule-1 in type C viral hepatitis

BACKGROUND/AIMS

Intercellular adhesion molecule-1 (ICAM-1) is one of the members of the immunoglobulin supergene family; it expresses in response to inflammatory mediators and activation. Circulating soluble ICAM-1 (sICAM-1) levels in acute and chronic viral hepatitis C virus infection were studied.

MATERIALS AND METHODS

Thirty blood samples from 10 patients with acute hepatitis C, and 36 blood samples from 25 patients with chronic hepatitis C were compared with those from 10 healthy volunteers, using the enzyme immunoassay method.

RESULTS

The mean circulating sICAM-1 activities in healthy volunteers was 339 +/- 93 ng/ml. Maximum values of sICAM-1 activities in acute (1394 +/- 502 ng/ml, P = 0.004) and chronic (662 +/- 477 ng/ml, P = 0.047) hepatitis C were increased. Acute hepatitis had a higher maximum circulating sICAM-1 activity than chronic hepatitis (P = 0.009). Longitudinal circulating sICAM-1 activities roughly correlated with the serum aminotransferase (ALT) activities. In acute viral hepatitis C, three patients developed an increase in circulating sICAM-1 activities before the manifestation of abnormal ALT activity. Circulating sICAM-1 activities showed a positive correlation with serum ALT activities (P < 0.001) and serum total bilirubin levels (P = 0.001) and a negative correlation with serum albumin levels (P = 0.01).

CONCLUSIONS

The present study suggested that ICAM-1 plays a role in the hepatocellular injury during viral hepatitis C infection.

VH gene usage is multiple myeloma: complete absence of the VH4.21 (VH4-34) gene

The immunoglobin heavy chain variable region (VH) gene usage in multiple myeloma (MM) has not been reported, although a few studies have incidentally identified the VH gene rearranged in small cohorts of MM patients. We used a reverse transcriptase-polymerase chain reaction based technique to analyze the VH gene usage in MM. The VH sequences were obtained after amplification of bone marrow cDNA using the seven VH family-specific and constant region primers. The VH sequences of 72 patients were successfully identified. The frequency of VH family usage in decreasing order was VH3>VH4>VH1>VH5>VH2>VH6>VH7 and corresponded to the functional germline complexity of the VH families. Individual VH genes (VH1-69, VH3-9, VH3-23, and VH3-30) were overrepresented in our cohort of MM patients; some VH genes [VH3-49, VH3-53, and VH4.21 (VH4-34)], which are rearranged with increased frequency in normal circulating B cells, autoimmune diseases, and other B-cell malignancies, were not detected in any MM patient. Compared with germline sequences, an average of 8.8% (range, 2.7% to 16.5%) of the nucleotides had evidence of mutation within each VH sequence. Based on these results, we conclude that (1) the VH gene usage in MM is unique compared with other malignant and nonmalignant B-cell populations, (2) the physiologic process of clonal deletion functions to remove clones that have rearranged VH genes (VH4.21) capable of expressing antibodies, which recognize self-antigens, and (3) the complete lack of VH4.21 gene rearrangement may help to partially explain the paucity of autoimmune phenomena in MM.

Motif identification neural design for rapid and sensitive protein family search

A new method, the motif identification neural design (MOTIFIND), has been developed for rapid and sensitive protein family identification. The method is an extension of our previous gene classification artificial neural system and employs new designs to enhance the detection of distant relationships. The new designs include an n-gram term weighting algorithm for extracting local motif patterns, an enhanced n-gram method for extracting residues of long-range correlation, and integrated neural networks for combining global and motif sequence information. The system has been tested and compared with several existing methods using three protein families, the cytochrome c, cytochrome b and flavodoxin. Overall it achieves 100% sensitivity and > 99.6% specificity, an accuracy comparable to BLAST, but at a speed of approximately 20 times faster. The system is much more robust than the PROSITE search which is based on simple signature patterns. MOTIFIND also compares favorably with BLIMPS, the Hidden Markov Model and PROFILESEARCH in detecting fragmentary sequences lacking complete motif regions and in detecting distant relationships, especially for members of under-represented subgroups within a family. MOTIFIND may be generally applicable to other proteins and has the potential to become a full-scale database search and sequence analysis tool.

American cockroach Cr-PI allergen induces lymphocyte proliferation and cytokine production in atopic patients

BACKGROUND

Previous studies have shown cockroach-induced antigen-specific IgE-mediated asthma. In cockroach-infested areas, more then 50% of asthmatic subjects may have positive skin reactions to this allergen. Partial purified Cr-PI allergen from American cockroaches contains allergens with molecular weights of 72 and 78 kDa; however, little is known about its effect on the lymphocyte proliferation and cytokine production.

OBJECTIVE

IgE synthesis is known to be regulated by interleukin-4 (IL-4) and interferon gamma (IFN gamma). Therefore, we studied Cr-PI allergen-induced cytokine production in atopic patients and healthy normal controls to understand each factors' role in the disease.

METHODS

Peripheral blood mononuclear cells (PBMC) from cockroach skin-sensitive patients and controls were stimulated with mitogen and Cr-PI for proliferative response and cytokine production. Cr-PI antigen-specific T-cell cultures of atopic patients and healthy normal controls were used to test Cr-PI-induced proliferation and cytokine mRNA expression.

RESULTS

PMBC of atopic subjects showed a significantly (P < 0.01) higher stimulation index for Cr-PI induced proliferation (SI = 11.8 +/- 3.7) when compared with that of non-atopic subjects (SI = 4.1 +/- 0.8) and cord bloods (SI = 2.1 +/- 0.4). Cr-PI-induced IL-4 was observed only in the PBMC of atopic patients, whereas Cr-PI-induced IFN gamma was detected in both atopic patients and normal controls. Likewise, Cr-PI-induced IL-4 mRNA expression in T-cell cultures was detected in all atopics but only one of nine controls.

CONCLUSION

IL-4 mRNA expression and IL-4 production in PBMC and T-cell cultures of atopic patients showed good correlation with clinical symptoms, skin-reactivity, specific IgE and proliferative response to Cr-PI. These results suggests that cockroach allergen may be a hidden cause of asthma and other atopic diseases.