Proteins in the early golgi compartment of Saccharomyces cerevisiae immunoisolated by Sed5p

The yeast tSNARE Sed5p is considered to mainly reside in the early Golgi compartment at the steady state of its intracellular cycling. To better understand this compartment, we immunoisolated a membrane subfraction having Sed5p on the surface (the Sed5 vesicles). Immunoblot studies showed that considerable portions (20-30%) of the Golgi mannosyltransferases (Mnt1p, Van1p, and Mnn9p) were simultaneously recovered while the late Golgi (Kex2p) or endoplasmic reticulum (Sec71p) proteins were almost excluded. The N-terminal sequences of the polypeptides detectable by Coomassie blue staining indicated that the prominent components of the Sed5 vesicles include Anp1p, Emp24p, Erv25p, Erp1p, Ypt52p, and a putative membrane protein of unknown function (Yml067c).

Long-term use of preservatives on rat nasal respiratory mucosa: effects of benzalkonium chloride and potassium sorbate

OBJECTIVES

The preservatives benzalkonium chloride (BZC) and potassium sorbate (PS) are widely used, not only for nasal drops, but also for eyedrops and cosmetics. However, there have been many case reports that consider lesions such as dermatitis or conjunctivitis to be the results of irritation induced by BZC or PS.

METHODS

We evaluated the histological changes after the long-term administration of BZC or PS on rat nasal respiratory mucosa. Forty rats were used for the BZC group and 40 rats for PS group. Animals in each group were divided into four subgroups The first subgroup received a low-concentration preservative solution that was commonly used for nasal sprays. The second subgroup received a high-concentration preservative solution that was reported to induce dermatitis in humans. The third and fourth subgroups received a steroid mixed preservative solution of low and high concentrations, respectively. The control group was administrated normal saline. After each group received 1, 2, and 4 weeks of topical administration, the symptomatic and histological changes on H&E stain were observed.

RESULTS

Sneezing and nasal rubbing with forelegs were observed in almost all subgroups by the seventh day of treatment. The preservatives induced nasal lesions, including intraepithelial glandular formation, inflammatory cell infiltration, vascular hyperplasia, and edematous change. The symptomatic and histological changes were pronounced with the prolonged duration of administration. Similar results were observed in the steroid mixed-solution groups. In the PS steroid mixed-solution group, however, symptoms and nasal lesions were reduced with the prolonged duration of administration.

CONCLUSION

It is our finding that even a low-concentration solution of preservative can lead to nasal lesion. Hence there is a strong need to develop both a preservative that can be safely and widely used and a nasal spray without preservatives.

Spontaneous programmed cell death of peripheral blood mononuclear cells from HIV-infected persons is decreased with interleukin-15

Interleukin 15 (IL-15) is an important regulatory cytokine in cellular immunity. In vitro replacement of IL-15 has been shown to enhance immunity in Human immunodeficiency virus type 1 (HIV-1) infected lymphocytes. We evaluated the effect of IL-15 on the survival of peripheral blood mononuclear cells of HIV patients by examining in vitro lymphocyte apoptosis, and correlated the process with Bcl-2 and Fas gene regulation. Peripheral blood mononuclear cells (PBMC) from 21 HIV-infected adults and 24 HIV-seronegative healthy individuals were isolated and cultured to determine the effect of escalating doses of IL-15 (0, 1, 10, 100, 1000 ng/mL) on apoptosis. Lymphocyte proliferation assay with (3H) TdR was measured and Bcl-2 and Fas gene regulation was observed. The results were as follows: 1) IL-15 reduced culture induced lymphocyte apoptosis in HIV patients in a dose dependent manner, and reached a plateau level at a concentration of 100 ng/ml; 2) IL-15 significantly reduced the level of apoptosis after 3 days (14%) and 5 days (15%) of culture in HIV patients, while no difference was observed in HIV (-) donors; 3) The percentage of viable cells among the total number of lymphocytes was significantly enhanced by 25% in HIV patients with IL-15; 4) Bcl-2 expression was decreased in HIV patients (53.9 +/- 12.3%) compared to HIV (-) donors (93.0 +/- 3.7%), and IL-15 increased Bcl-2 expression by 21.2 +/- 5.2% in HIV patients; 5) Fas expression was increased in HIV patients (70.2 +/- 4.6%) compared to HIV (-) donors (32.4 +/- 4.3%), and IL-15 increased Fas expression by 8.4 +/- 1.2% in HIV (-) donors. Our findings indicate that IL-15 may influence immunologic abnormalities in HIV infection, particularly its ability to prevent apoptosis of lymphocytes by suppressing the down-modulation of Bcl-2. This may provide an experimental basis for IL-15 immunotherapy.

Conductimetric membrane strip immunosensor with polyaniline-bound gold colloids as signal generator

For point-of-care examination, an immuno-chromatographic assay system based on conductimetric detection was investigated by utilizing, as signal generator, colloidal gold with polyaniline bound on the metal surface. Although the gold is a widely used label for antibodies to produce colorimetric signals, the tracer does not lend itself for a suitable electric conduction along the gold particles due to the presence of protein barriers (e.g. immunoglobulin and blocking agent) against electron transfer. To overcome this problem, we introduced a conducting polymer, for instance, polyaniline, as a conductivity-modulating agent on the gold surface after immobilizing an antibody specific to human albumin used as model analyte. This novel signal generator amplified the conductimetric signal 4.7 times compared with the plain gold, and the signal was also maximum 2.3-fold higher than that from the photometric system under the same analytical conditions. The latter effect resulted from an exponential pattern in the dose-response curve of the electric signal that was different from the conventional sigmoidal shape.

Activation of p38 mitogen-activated protein kinase and mitochondrial Ca(2+)-mediated oxidative stress are essential for the enhanced expression of grp78 induced by the protein phosphatase inhibitors okadaic acid and calyculin A

We have reported that treatment with okadaic acid, a potent protein phosphatase inhibitor, has the ability to enhance the synthesis of the 78-kDa glucose-regulated protein (GRP78). This article reports our investigation of another protein phosphatase inhibitor, calyculin A, demonstrating the signaling pathways elicited by the protein phosphatase inhibitors that lead to the induction of grp78. Our data showed that the induction process is abolished by SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (p38(MAPK)). Phosphorylation-activation of p38(MAPK) in the treated cells was indicated by its own phosphorylation, as shown by double Western blotting analyses and directly confirmed by the in vitro kinase assay using MAPK-activated protein kinase-2, a well-known downstream effector of p38(MAPK), as a substrate. The involvement of p38(MAPK) in this process is further substantiated by using transient transfection assays with a plasmid, pGRP78-Luc, which contains a 0.72-kbp stretch of the grp78 promoter. By exploiting the same transfection assay, we demonstrated that the up-regulation of the grp78 promoter by the protein phosphatase inhibitors is suppressed in the presence of the cytoplasmic calcium chelator bis(aminophenoxy)ethane N,N'-tetraacetic acid, the mitochondria calcium uniporter inhibitor ruthenium red as well as the antioxidants N-acetyl cysteine and pyrrolidinedithiocarbamate. Taken together, our results lead us to conclude that treatment with the protein phosphatase inhibitors would activate the signaling pathways involving p38(MAPK) and mitochondrial calcium-mediated oxidative stress and that these pathways must act in concert in order to confer the induction of grp78 by okadaic acid and calyculin A.

Angiocentric lymphoma of the head and neck: patterns of systemic failure after radiation treatment

PURPOSE

To investigate the patterns of systemic failure and the clinical outcome in patients with angiocentric lymphoma of the head and neck who were treated with radiation alone, and to discuss the optimal mode of treatment for these patients.

PATIENTS AND METHODS

We reviewed the records of 92 patients with stage I or II angiocentric lymphoma who were treated at Yonsei Cancer Center between 1976 and 1994. All patients were treated with involved-field irradiation. Radiation doses ranged from 40 to 60 Gy (median dose, 50.4 Gy). Treatment response, patterns of treatment failure including systemic failure, and clinical outcome after radiation treatment were analyzed.

RESULTS

The most frequently involved site was the nasal cavity, either alone or in conjunction with other sites. In 16 patients (17.4%), angiocentric lymphoma was accompanied by cervical lymphadenopathy. Disease was classified as stage I in 62 patients (67.4%) and stage II in 30 patients (32.6%). After completion of radiation treatment, 61 patients (66.3%) achieved a complete response and 16 (17.4%) a partial response. Half of the patients (50.0%) ultimately experienced local recurrence with or without other components of failure, whereas regional failure was relatively uncommon (10.9%). Systemic failure occurred in 25.0% of patients during follow-up. Six patients had histologic findings identical to those at the time of the original disease (group I), whereas four patients exhibited morphologic features of frank lymphomas (group II). The majority of patients with systemic relapse had the predilection sites for widespread extranodal involvement, such as the skin, brain, lung, gastrointestinal tract, or testes. In addition, seven patients died from various medical illnesses or immunologic disorders, including hemophagocytic syndrome and second primary cancers (group III). After a median follow-up of 56 months, the overall survival and disease-free survival rates for all patients were 40.1% and 37.8%, respectively. All patients except one with systemic failure died within 1 year.

CONCLUSION

Treatment with radiation alone had suboptimal results, partly because of the occurrence of a variety of systemic failure with diverse clinicopathologic features. Given the frequent occurrence of systemic failure after radiation treatment, we believe that the multimodality treatment approach containing more effective chemotherapeutic agents should be incorporated in the treatment of angiocentric lymphoma confined to the head and neck.

Activation of human neutrophils by a synthetic anti-microbial peptide, KLKLLLLLKLK-NH2, via cell surface calreticulin

We previously reported that a synthetic anti-bacterial peptide, KLKLLLLLKLK-NH2 (L5), showed significant chemotherapeutic activity in methicillin-resistant Staphylococcus aureus-infected mice, and its ability to activate human neutrophils was related to its chemotherapeutic activity. In this study, we found that activation of neutrophils by L5 was inhibited by pertussis toxin, suggesting that GTP-binding protein (G-protein) participates in this process. We isolated an L5-binding protein, which turned out to be human calreticulin, with a molecular mass of 60 kDa from neutrophil membranes. From experiments using an anti-calreticulin antibody, we proposed that calreticulin is partly localized on the surface of neutrophils, and L5-bound calreticulin transmits a signal into cells via G-protein to activate neutrophils to generate superoxide anion.

Low convulsive activity of a new carbapenem antibiotic, DK-35C, as compared with existing congeners

Since carbapenems and cephalosporins have been suggested to induce convulsive side effects through an inhibitory action on the central gamma-aminobutyric acid (GABA)-mediated inhibitory transmission, the present study evaluated the convulsive activity of a new carbapenem antibiotic (1R,5S,6S)-6[(R)-1-hydroxyethyl]-2-[(3S,5S)-5(S-methyl-4thiomorpholin ylcarbonyl)pyrrolidin-3-thio]-l-methylcarbapen-2-em-3- carboxylic acid (DK-35C) in in vitro and in vivo experiments, in comparison with cefazolin, imipenem and meropenem. In in vitro experiments, their abilities to inhibit [3H]muscimol (5 nM) binding to GABA(A) receptors were measured using crude synaptic membranes prepared from the rat cerebral cortex. The concentrations (mM) of the antibiotics which inhibit 50% of the specific binding, were 0.6 for imipenem, 1.8 for cefazolin, 15.4 for DK-35C and 27.6 for meropenem. In in vivo experiments, intracerebroventricular (i.c.v.) injections of cefazolin, imipenem and DK-35C induced convulsions in a dose-dependent manner in rats. The doses (nmol/rat) of the antibiotics which induce convulsions in 50% of rats, were 57 for imipenem, 96 for cefazolin, 377 for DK-35C and >3000 for meropenem. In the mouse pentylenetetrazole (PTZ) convulsive model, intravenous pretreatment with cefazolin (800 mg/kg) or imipenem (200 mg/kg) shifted the dose-response curve of PTZ (i.p.) to the left, indicating enhancement of the convulsive activity of PTZ. However, pretreatment with cefazolin, meropenem or DK-35C at a dose of 400 mg/kg did not produce any marked effects on the convulsive activity of PTZ compared with the saline vehicle-pretreated control. The results clearly demonstrate a good correlation between in vitro GABA(A) receptor binding assay and in vivo i.c.v. convulsive model using rats, and suggest that DK-35C may possess a relatively weak convulsive activity mediated through an interaction with GABA(A) receptors.

Clinical significance of neck node metastasis in squamous cell carcinoma of the maxillary antrum

PURPOSE

To further clarify the clinical significance of neck node metastasis in squamous cell carcinoma of the maxillary sinus (maxillary SCC).

MATERIALS AND METHODS

The medical charts of the 116 patients with maxillary SCC were retrospectively reviewed. Twelve patients (10.3%) presented initially with neck node metastases, and 14 (13.5%) of 104 node-negative patients subsequently developed regional recurrence during the follow-up period. The high-risk factors for neck node metastasis, patterns of regional failure, and survival for node-positive patients were analyzed with the patient cohort that had largely been treated with radiation alone.

RESULTS

Of the various factors, the tumor extension to the nasopharynx or oral cavity was the statistically significant determinants predictive of neck node metastasis at the initial diagnosis. During the follow-up period, regional failure was far less common than local failure (19.0% v 68.1%), and the majority of regional failures were accompanied by local recurrences. The oral cavity extension and control status of local disease were the high-risk factors for subsequent development of regional recurrence in node-negative patients. The overall 5-year survival rate for node-positive patients (16.7%) showed a poorer outcome compared with that for node-negative patients (31.3%), but it was similar to that of T4N0 patients (26.6%). Although patients who subsequently developed neck node recurrence during follow-up represented a dismal prognosis, uncontrolled local diseases in these patients still remained a major problem, resulting in a poor prognosis.

CONCLUSIONS

Despite an unfavorable prognosis of patients with neck node metastasis, an aggressive trial to achieve maximum local control of the primary tumor was considered to be more important than elective neck treatments.

Preventive effects of the heparin-coated stent on restenosis in the porcine model

The coronary stent reduces acute coronary arterial occlusion and late restenosis during and after coronary intervention. However, stent thrombosis and restenosis are still major limitations in the widespread use of the coronary stent. Local drug delivery using the heparin-coated stent may be a new approach, which reduces the incidence of stent thrombosis and restenosis. In order to evaluate the effects of the heparin-coated stent on stent restenosis, heparin-coated stents were compared with control stents in a porcine coronary stent restenosis model. Stent overdilation injury (stent:artery = 1.3:1.0) was performed with bare Wiktor stents (group I, n = 10) and heparin-coated Wiktor stents (group II, n = 20; HEPAMED, Medtronics) in porcine coronary arteries. Follow-up quantitative coronary angiography (QCA) was performed at 4 weeks after stenting, and histo-pathologic assessments of stented porcine coronary arteries were compared in both groups. On QCA, percent diameter stenosis was significantly higher in group I than in group II (16.3% +/- 6.62% vs. 9.6% +/- 5.06%, P < 0.05). The injury score of stented porcine coronary arteries was the same in both groups (1. 26 +/- 0.23 vs. 1.20 +/- 0.22). The area of pathologic stenosis of the stented arteries was higher in group I than in group II (41.6% +/- 12.5% vs. 27.1% +/- 9.9%, P < 0.005). The neointimal area was higher in group I than in group II (4.58 +/- 1.41 mm(2) vs. 2.57 +/- 1.07 mm(2), P < 0.05). By immunohistochemistry, the proliferating cell nuclear antigen (PCNA) index was higher in group I compared with group II (11.2% +/- 6.75% vs. 6.3% +/- 4.14%, P < 0.05). The heparin-coated stent is effective in the prevention of late coronary stent restenosis in a porcine coronary stent restenosis model. This may be related to the inhibition of neointimal cell proliferation.

Discrimination of herbal medicines according to geographical origin with near infrared reflectance spectroscopy and pattern recognition techniques

Herbal medicines have an important role in clinical therapy in Asian countries such as Korea, Japan, and China. The objective of this study is to develop a nondestructive and accurate analytical method to discriminate herbal medicines according to geographical origin. Even though they are the same species, their qualities are different by growing conditions such as climate and soil. Near infrared (NIR) reflectance spectroscopy and a pattern recognition technique were applied for discrimination of herbal medicines according to geographical origin (Korea and China). Astragali Radix (AR), Ganoderma, and Smilacis Rhizoma (SR) were examined. It is shown that the representative NIR reflectance spectra in each group are different according to geographical origin after second derivatization to enhance spectral features. Also, the NIR reflectance spectra of Chinese and Korean samples were differentiated using principal component (PC) score plots. To establish the discrimination rule, Mahalanobis distance and discriminant analysis with PLS2 were utilized.

Size assessment of adenoid and nasopharyngeal airway by acoustic rhinometry in children

Adenoid hypertrophy is known as the most common cause of nasal obstruction in children; thus, adenoidectomy with, or without, tonsillectomy is one of the most commonly performed surgical procedures in the paediatric population. Although many methods have been suggested, few studies have reported on how to assess adenoid size, pre-operatively. Acoustic rhinometry is an objective technique as well as a non-invasive method, which can be easily used in young children. This study confirmed that acoustic rhinometry is a non-invasive and objective technique for assessing the geometry of the nasal cavity and nasopharynx. Forty children were evaluated using symptomology, two different radiological measurements and acoustic rhinometry; the results were compared with endoscopic findings. Clinical symptoms and A/N ratio measured with Fujioka's method significantly correlated with the endoscopic assessment findings (r = 0.769 and 0.604 respectively). Significant increases in the cross-sectional area and volume of the nasopharynx were observed at the adenoid notch after adenoidectomy (p < 0.005 and p < 0.005, respectively). Acoustic rhinometry showed a high degree of correlation of which adenoid occupied the nasopharyngeal airway under endoscopic examination (r = 0.771). Thus, the study concluded that acoustic rhinometry can be as good an objective method for measuring adenoid sizes as endoscopy and can be used as one of the pre-operative examination tools for adenoidectomy.

A case of prominent epicardial fat mimicking a tumor on echocardiography

Epicardial fat may anteriorly produce an echo-free space that can be mistaken for pericardial fluid. We recently experienced a 67-year-old woman with prominent epicardial fat which was presented as an echogenic tumor-like mass. She underwent open pericardiostomy to relieve large amount of pericardial effusion. Operative findings revealed only prominent epicardial fat. Biopsy of the pericardial and fat tissues revealed an inflammation and normal fat cells without any malignant cell infiltration.

Chondroblastoma: MR characteristics with pathologic correlation

PURPOSE

The purpose of this study was to describe the MR findings of chondroblastoma with pathologic correlation.

METHOD

In 22 patients with pathologically proven chondroblastoma, MR signal characteristics were correlated with pathological findings.

RESULTS

On T2-weighted images, 12 (55%) lesions were hyperintense with hypointense areas in 9 lesions, whereas 10 (45%) were hypointense. Therefore, 19 of 22 (86%) lesions with pathologic correlation had hypointense areas entirely (n = 10) or partly (n = 9) on T2-weighted images. On gadolinium-enhanced images, 13 (59%) lesions showed lobular enhancement and 9 (41%) showed marginal and septal enhancement. Low signal intensity on T2-weighted MR images was most strongly associated with an abundance of immature chondroid matrix, hypercellularity of the chondroblasts, calcifications, and hemosiderin on histology.

CONCLUSION

Chondroblastoma was found to show hypointense portions on T2-weighted images. Signal intensity on T1- and T2-weighted MR images in chondroblastoma was dependent on the amounts of histopathological components.

Diagnostic p53 expression in gastric endoscopic mucosal resection

Endoscopic mucosal resection (EMR) has been standardized for the treatment of intestinal type of intramucosal gastric carcinomas, and careful histological examination of the resected specimen is important for further treatment. To evaluate the diagnostic utility of p53 expression in gastric EMR samples, using immunohistochemical staining, we examined 24 gastric carcinomas (22 intestinal types and two diffuse types) and 20 adenomas removed by EMR. Intestinal type of adenocarcinomas revealed strong p53 expression in 13 cases (59%), weak in four cases (18%), and negative in five cases (23%). Resection margins of 11 carcinomas were involved in the carcinoma cells, which showed the same p53 expression pattern with main carcinoma cells. Squeezed carcinoma cells, remaining in resection margins, were definitely identified by strong p53 expression in seven cases of which the main tumor strongly expressed p53. Microscopic in situ carcinoma could be easily detected in p53 immunostaining. Multifocal involvement and submucosal invasion of carcinomas could be demarcated easily and definitely by strong p53 expression of carcinoma cells. All adenomas showed diffuse weak p53 expression. The difference of p53 expression (p< 0.001) could be used as a differential diagnosis between adenomas and carcinomas. According to these results, we propose that for careful histological examination in hospital diagnosis, both histological evaluation and p53 immunostaining are important diagnostic parameters in EMR samples of the intestinal type of gastric carcinomas.

The development of digital library system for drug research information

The sophistication of computer technology and information transmission on internet has made various cyber information repository available to information consumers. In the era of information super-highway, the digital library which can be accessed from remote sites at any time is considered the prototype of information repository. Using object-oriented DBMS, the very first model of digital library for pharmaceutical researchers and related professionals in Korea has been developed. The published research papers and researchers' personal information was included in the database. For database with research papers, 13 domestic journals were abstracted and scanned for full-text image files which can be viewed by Internet web browsers. The database with researchers' personal information was also developed and interlinked to the database with research papers. These database will be continuously updated and will be combined with world-wide information as the unique digital library in the field of pharmacy.

Synthesis and biological activities of C-2, N-9 substituted 6-benzylaminopurine derivatives as cyclin-dependent kinase inhibitor

In this study, C-2, N-9 substituted 6-benzylaminopurine derivatives were synthesized and their inhibitory effects on cyclin-dependent kinase (CDK2) were evaluated. The effect of substituents at the C-2 and N-9 positions of substituted purine was investigated. Among the compounds tested, compound 7b-iii (6-benzylamino-2-thiomorpholinyl-9-isopropylpurine) was the most active inhibitor (IC50 = 0.9 microM). Compound 7b-iii showed 10-fold higher activity compared to olomoucine and almost the same activity as roscovitine. Results from structure-activity relationship studies should allow the design of more potent and selective CDK inhibitors, which may provide an effective therapy for cancer or other CDK dependent diseases.

Analysis of calsequestrin gene expression using green fluorescent protein in Caenorhabditis elegans

The calsequestrin gene of Caenorhabditis elegans is expressed in body-wall muscle cells during muscle development. In order to study the body-wall muscle specific regulation of the calsequestrin gene expression, approximately 2 kb upstream sequences of the calsequestrin gene were analyzed. Transcriptional fusion constructs utilizing green fluorescent protein as a reporter gene were made and microinjected to produce germ-line transformed transgenic C. elegans. The expression of green fluorescent protein was observed in the body-wall muscles of live transgenic animals under fluorescence microscopy. Deletion analyses of upstream sequences have revealed a putative promoter sequence and a regulatory element which appeared to enhance reporter gene expression. Both sequence elements are juxtaposed to constitute a 260 bp regulatory region approximately 260 bp upstream from the putative translational initiation codon. Several possible binding sites for transcription factors were identified including the sites for YY1 and NF-W2, a muscle specific zinc finger transcription factor, and an ubiquitous enhancer binding protein, respectively. Interestingly, this region also contains a 20 bp sequence element identical to those found in the mouse dystrophin gene, which suggests a possible role of this regulatory region in muscle specific gene regulation.

Synthesis and antibacterial activity of 1 beta-methylcarbapenem having a 1,3-diazabicyclo[3.3.0]octan-4-one moiety, Part II

The synthesis of a new series of 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octan-4-one moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria are tested and the effect of substituent on the bicyclic ring was investigated. A particular compound (11 h) having aminoethyl group showed the most potent antibacterial activity.

Variations in meniscofemoral ligaments at anatomical study and MR imaging

PURPOSE

To demonstrate variations in the meniscofemoral ligaments (ligaments of Wrisberg and Humphrey) at anatomical study and magnetic resonance (MR) imaging.

DESIGN

Twenty-eight cadaveric knees were partially dissected for the examination of the meniscofemoral ligaments. One hundred knee MR examinations were reviewed by two experienced musculoskeletal radiologists. Proximal variations in the meniscofemoral ligaments at MR imaging were classified into three types according to the attachment site: type I, medial femoral condyle; type II, proximal half of the posterior cruciate ligament (PCL); type III, distal half of the PCL. Distal variations were classified into vertical or oblique types according to the orientation of the intermediate signal at the interface of the ligament and lateral meniscus.

RESULTS

At anatomical study, six cases showed variations in the proximal insertion site of the meniscofemoral ligaments. At MR imaging 93 cases had one or more meniscofemoral ligaments, giving a total of 107 ligaments: 90 ligaments of Wrisberg and 17 ligaments of Humphrey. Forty-one ligaments of Wrisberg were type I, 28 type II, 19 type III, and with two indeterminate type, while 6 ligaments of Humphrey were type I and the remaining 11 were indeterminate. Seven cases showed no meniscofemoral ligament. Of the 107 meniscofemoral ligaments, the distal insertion orientation was of vertical type in 10 ligaments, oblique type in 70 and unidentified in 27.

CONCLUSION

An understanding of the high incidence of meniscofemoral ligament variations may help in the interpretation of knee MR studies.

Enhanced cellular immunity to hepatitis C virus nonstructural proteins by codelivery of granulocyte macrophage-colony stimulating factor gene in intramuscular DNA immunization

Hepatitis C virus (HCV) nonstructural (NS) proteins appeared to be important targets for HCV vaccine development, since NS-specific T-helper-cell responses are associated with clearance from acute HCV infection. In this report, we have constructed a plasmid, pTV-NS345, that encodes the HCV NS3, NS4 and NS5 proteins (NS345) and a bicistronic plasmid, PTV-NS345/GMCSF, in which the HCV NS345 polyprotein and GMCSF are translated independently. Intramuscular inoculation with pTV-NS345 plasmid DNA into the Buffalo rats generated both antibody and T-cell proliferative responses to each NS protein. The expression of GMCSF, together with HCV NS345 proteins, appeared to significantly increase T-cell proliferative responses. In particular, the inoculation of a bicistronic plasmid generated higher T-cell proliferative responses to each NS protein than did the coinjection of two separate plasmids, pTV-NS345 and pTV-GMCSF. These results demonstrate that the codelivery of GMCSF augmented HCV NS345-specific cellular immunity and that the intensity of the immunity was differed depending on how GMCSF gene is codelivered.

An aural myiasis case in a 54-year-old male farmer in Korea

A 54-year-old male farmer residing in Chunchon, Korea, complaining of blood tinged discharge and tinnitus in the left ear for two days, was examined in August 16, 1996. Otoscopic examination revealed live maggots from the ear canal. The patient did not complain of any symptoms after removal of maggots. Five maggots recovered were identified as the third stage larvae of Lucilia sericata (Diptera: Calliphoridae). This is the first record of aural myiasis in Korea.

An infestation of the mite Sancassania berlesei (Acari: Acaridae) in the external auditory canal of a Korean man

We here report the case of a storage mite, Sancassania berlesei, infestation in the external auditory canal of a 46-yr-old male. He complained of feeling a foreign body and itching in the left external auditory canal for 1 mo, with accompanying otalgia for 3 days. Considering the duration of the patient's complaint and the 8-9-day life cycle of the mite, the mites are believed to have lived in the patient's ear for more than 3 generations.

Effect of Helicobacter pylori infection on antral gastrin and somatostatin cells and on serum gastrin concentrations

OBJECTIVES

Helicobacter pylori infection induces selective reduction of the number of antral D-cells and results in abnormal regulation of serum gastrin secretion. The purpose of this study was to investigate the relationship between H. pylori infection and the numbers of G-cells and D-cells.

METHODS

The numbers of antral G-cells and D-cells, the ratio of G-cells to D-cells and fasting serum gastrin concentrations were compared between 37 patients with (29 with duodenal ulcers and 8 with gastric ulcers) and 33 without H. pylori infection (22 with duodenal ulcers and 11 with gastric ulcers). Serum gastrin concentrations were measured using the radioimmunoassay technique. Antral mucosal biopsy specimens were examined using immunohistochemical staining with antibodies specific for gastrin and somatostatin and the numbers of G-cells and D-cells per gastric gland were counted.

RESULTS

Fasting serum gastrin concentrations were significantly higher in patients with H. pylori infection compared to patients without infection (80.3 +/- 23.5 vs 47.6 +/- 14.1 pg/ml, p < 0.001). The number of G-cells per gastric gland was similar in infected and uninfected patients (7.1 +/- 3.1 vs 7.3 +/- 3.9, respectively, p > 0.5). The number of D-cells was significantly lower in patients with H. pylori infection than in uninfected patients in both duodenal and gastric ulcer patients (1.3 +/- 0.4 vs 2.5 +/- 1.6, respectively, p < 0.001). The ratio of G-cells to D-cells was also significantly higher in infected patients compared with uninfected patients for both gastric and duodenal ulcers (5.7 +/- 2.7 vs 3.5 +/- 1.9, respectively, p < 0.001).

CONCLUSIONS

These results strongly suggest that Helicobacter pylori infection induces reduction of the number of antral D-cells. The resulting relative hypofunction of the inhibitory action of D-cells against G-cells may be responsible for increased serum gastrin secretion.

The effects of antiplatelet agents in the prevention of ventricular tachyarrhythmias during acute myocardial ischemia in rats

Experiments were performed in rat models to study the effectiveness of various antiplatelet agents in the prevention of ventricular tachyarrhythmias during acute myocardial ischemia. The time to the onset of ST-segment elevation and initiating ventricular arrhythmias, frequency and incidence of ventricular arrhythmias, and mortality rates were observed during acute myocardial ischemia (20 minutes) induced by ligation of the proximal left anterior descending coronary artery (LAD) in anesthetized rats. Four groups were studied: Control group (n = 10, not pretreated); Aspirin pretreated group (n = 10, 300 mg/kg p.o. for 1 wk); Ticlopidine pretreated group (n = 10, 200 mg/kg p.o. for 1 wk); and Abciximab (Platelet glycoprotein IIb/IIIa receptor antagonist) pretreated group (n = 10, 2 mg/kg i.v. 10-20 minutes before an experiment). No significant difference was observed in the time to the onset of ST-segment elevation and ventricular arrhythmias between the groups. The incidence of ventricular tachycardia (VT) in the abciximab group was significantly lower than in the control group (p < 0.05) and ventricular fibrillation (VF) in the aspirin and ticlopidine group was significantly lower than in the control group (p < 0.05). The mortality rate in the ticlopidine group was significantly lower than in the control group (p < 0.01). This study suggests aspirin, ticlopidine, and abciximab can effectively prevent VT or VF during acute myocardial ischemia induced by nonthrombotic occlusion and its antiarrhythmic effect may lead to prolonged survival.

A case of AV reentrant tachycardia due to a concealed accessory pathway with retrograde conduction manifested by isoproterenol

Retrograde conduction of the concealed accessory pathway (AP) is a prerequisite for the induction of atrioventricular reentrant tachycardia (AVRT). In patients with AVRT due to a concealed AP, the absence of retrograde conduction of the AP in the baseline state has rarely been reported. We report a case of AVRT due to a concealed left lateral AP, in which the retrograde conduction was absent in the baseline state and manifested by isoproterenol infusion. A 61-year-old man had suffered from intermittent palpitation for 17 years. A narrow QRS complex tachycardia with a retrograde P wave in the ST segment was recorded in 24-h Holter monitoring. An electrophysiologic study was performed while he was in a nonsedated state. No ventriculoatrial conduction over either the normal atrioventricular conduction system or the AP was demonstrated in the baseline state. Isoproterenol was infused at a rate of 1.0 microg/min. Retrograde conduction over the AP became manifest and AVRT was induced. The AP was ablated with radiofrequency energy at the left free wall. After ablation of the AP, no tachycardia was induced. To the authors'best knowledge, only 1 other similar case has been reported in the literature.

Minimizing artifacts caused by metallic implants at MR imaging: experimental and clinical studies

OBJECTIVE

The purpose of this study was to investigate the effect of metallic implant positioning on MR imaging artifacts, to determine the optimal imaging conditions for minimizing artifacts, and to show the usefulness of artifact-minimizing methods in imaging of the knee.

MATERIALS AND METHODS

Using MR images of experimental phantoms (titanium alloy and stainless steel screws), we compared the magnitude of metal-induced artifacts for various pulse sequences, different imaging parameters for the fast spin-echo sequence, and different imaging parameters for several incremental angles between the long axis of the screw and the direction of the main magnetic field. In clinical MR imaging of knees with metallic implants (n = 19), we assessed geometric distortion of anatomic structures to compare the influence of different pulse sequences (n = 19), frequency-encoding directions (n = 7), and knee positions (n = 15).

RESULTS

Titanium alloy screws consistently produced smaller artifacts than did stainless steel screws. In experimental MR studies, artifacts were reduced with fast spin-echo sequences, with a screw orientation as closely parallel to the main magnetic field as possible, and, particularly, with smaller voxels that correlated positively with artifact size (R2 = .88, p < .01). In clinical MR studies, fast spin-echo MR imaging obscured articular structures less than did spin-echo imaging (8/19 patients). In particular, the anterior-posterior frequency-encoding direction (3/7 patients) and the flexion position of the knee (5/15 patients) were effective in reducing artifacts.

CONCLUSION

MR artifacts can be minimized by optimally positioning in the magnet subjects with metallic implants and by choosing fast spin-echo sequences with an anterior-posterior frequency-encoding direction and the smallest voxel size.

American families with Crohn's disease have strong evidence for linkage to chromosome 16 but not chromosome 12

BACKGROUND & AIMS

Two European genome-wide screens for inflammatory bowel disease have identified two significant regions of linkage on chromosomes 16 (IBD1) and 12 (IBD2) and two regions with suggestive levels of significance (chromosomes 3p and 7q). The aim of this study was to determine if there was evidence for linkage to these regions in non-Jewish and Ashkenazi Jewish families multiplex for Crohn's disease from the United States.

METHODS

One hundred forty-eight affected relative pairs, 34% Ashkenazim, were genotyped with 10-14 highly polymorphic markers overlying each candidate region. Nonparametric multipoint and two-point linkage analyses were performed.

RESULTS

Significant evidence for replication of linkage was found only for the chromosome 16 locus, IBD1, maximal at D16S769 (nonparametric linkage score [NPL], 2.49; P = 0.007). Analysis by ethnicity showed stronger evidence for Ashkenazim (D16S769; NPL = 2. 52; P = 0.007) than for non-Jewish white populations (D16S401; NPL = 1.40; P = 0.082). There was no significant evidence for replication on chromosome 12 (IBD2). Minimal evidence for extension of linkage evidence was observed for the chromosomes 3p and 7q regions.

CONCLUSIONS

American families, particularly Ashkenazim, have significant evidence for the Crohn's disease susceptibility locus, IBD1, on chromosome 16, but not for IBD2 on chromosome 12.

Lumbricin I, a novel proline-rich antimicrobial peptide from the earthworm: purification, cDNA cloning and molecular characterization

A novel antimicrobial peptide was isolated and characterized from the earthworm, Lumbricus rubellus. The antimicrobial peptide was purified to homogeneity by a heparin-affinity column and C18 reverse-phase HPLC, and named lumbricin I. Lumbricin I was a proline-rich antimicrobial peptide of 62 amino acids (15% proline in molar ratio; molecular mass, 7231 Da), whose complete sequence was determined by a combination of peptide sequence and cDNA analysis. The peptide and cDNA sequence analysis revealed that lumbricin I was produced as a precursor form consisting of 76 amino acids, with 14 residues in a presegment and 62 residues in mature lumbricin I. Lumbricin I showed antimicrobial activity in vitro against a broad spectrum of microorganisms without hemolytic activity. In addition, a 29-amino acid peptide, named lumbricin I(6-34), which was derived from residues 6-34 of lumbricin I, showed marginally stronger antimicrobial activity than lumbricin I. Northern blot analysis on total RNA revealed that expression of lumbricin I gene was not induced by bacterial infection, but was constitutively expressed. Furthermore, the expression of lumbricin I gene was specific in adult L. rubellus: Lumbricin I mRNA was detected only in adult L. rubellus, but not in eggs and young L. rubellus.

Optimal induction of hepatitis C virus envelope-specific immunity by bicistronic plasmid DNA inoculation with the granulocyte-macrophage colony-stimulating factor gene

In this study, we have constructed various DNA vaccine vectors that carried hepatitis C virus (HCV) envelope genes without and with the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene in several different ways. In Buffalo rats that received plasmids carrying the HCV envelope genes, which encode envelope proteins E1 and E2, both antibody and lymphoproliferative responses against these proteins were induced. These responses were greatly enhanced by the codelivery of the GM-CSF gene. In particular, inoculation with a bicistronic plasmid that independently expressed the GM-CSF gene and the envelope genes in the same construct generated the highest antibody titers and significantly increased lymphoproliferative responses against these proteins. Moreover, strong antibody responses to homologous and heterologous hypervariable region 1 peptides were elicited in the immunized rats.

A novel DNA-binding protein bound to the mitochondrial inner membrane restores the null mutation of mitochondrial histone Abf2p in Saccharomyces cerevisiae

The yeast mitochondrial HMG-box protein, Abf2p, is essential for maintenance of the mitochondrial genome. To better understand the role of Abf2p in the maintenance of the mitochondrial chromosome, we have isolated a multicopy suppressor (YHM2) of the temperature-sensitive defect associated with an abf2 null mutation. The function of Yhm2p was characterized at the molecular level. Yhm2p has 314 amino acid residues, and the deduced amino acid sequence is similar to that of a family of mitochondrial carrier proteins. Yhm2p is localized in the mitochondrial inner membrane and is also associated with mitochondrial DNA in vivo. Yhm2p exhibits general DNA-binding activity in vitro. Thus, Yhm2p appears to be novel in that it is a membrane-bound DNA-binding protein. A sequence that is similar to the HMG DNA-binding domain is important for the DNA-binding activity of Yhm2p, and a mutation in this region abolishes the ability of YHM2 to suppress the temperature-sensitive defect of respiration of the abf2 null mutant. Disruption of YHM2 causes a significant growth defect in the presence of nonfermentable carbon sources such as glycerol and ethanol, and the cells have defects in respiration as determined by 2,3,5,-triphenyltetrazolium chloride staining. Yhm2p may function as a member of the protein machinery for the mitochondrial inner membrane attachment site of mitochondrial DNA during replication and segregation of mitochondrial genomes.

Infection with Helicobacter pylori expressing the cagA gene is not associated with an increased risk of developing peptic ulcer diseases in Korean patients

BACKGROUND

Helicobacter pylori strains possessing the cagA gene have been postulated to have a disease-specific relationship to peptic ulcer. The purpose of this study was to investigate the relationship between the infection with Helicobacter pylori expressing the cagA gene and the development of peptic ulcer diseases in Korean patients.

METHODS

Genomic DNA and bacterial mRNA in the gastric mucosa were amplified by polymerase chain reaction (PCR) and reverse transcription PCR, using synthetic oligonucleotide primers to cagA genes to compare the prevalence of cagA genes in 35 patients with non-ulcer gastritis and 99 patients with gastric or duodenal ulcer disease (53 and 46, respectively). Two different primer sets for the cagA gene were used. The first primer set amplified a 298-bp region (nucleotides 1751-2048), and the second set amplified a 349-bp region (nucleotides 1228-1249).

RESULTS

The expected 298 and 349-bp PCR amplicons were identified as follows: 1) 32 (91.4%) and 30 (85.7%) of 35 non-ulcer gastritis patients; 2) 5 1 (96.2%) and 50 (94.3%) of 53 benign gastric ulcer patients; and 3) 46 (100.0%) and 40 (87.0%) of 46 duodenal ulcer patients, respectively.

CONCLUSION

These results strongly suggest that the cagA gene will not prove to be a useful marker to distinguish disease-specific H. pylori strains in the development of peptic ulcer diseases in Korean patients.

Hepatitis C virus envelope DNA-based immunization elicits humoral and cellular immune responses

The vaccine development for hepatitis C virus (HCV) is highly urgent to prevent non A and non B hepatitis. It was recently shown that the HCV envelope proteins appeared to the key viral antigens to induce protective immunity. To generate immune responses to the HCV envelope proteins on the DNA-based immunization, various envelope gene-containing plasmids were constructed. For efficient expression and secretion of envelope proteins, the signal sequence of each envelope protein was replaced with either herpes simplex virus type-1 (HSV-1) gD or signal sequence of gD and truncated C-terminal hydrophobic regions of envelope proteins. The intramuscular injection of these plasmids generated a significant level of antibody titers to the E1 and E2 proteins, which maximally reached 850 and 25,000 respectively. The secreted form of each envelope protein and the fusion of the highly immunogenic gD proteins were shown to have no significant effect on generating immune responses to the envelope proteins. In addition, immunized rats appeared to generate antibodies directed to the homologous HVR-1 peptide. Splenic lymphocytes from immunized rats were shown to induce significant T-cell proliferative responses with the stimulation of recombinant E1 and E2 proteins. Our results demonstrated that the HCV envelope-DNA based immunization could elicit both humoral and cellular immune responses.

Electroretinographic evaluation in adult diabetics

In cross-sectional fashion, we recorded the maximal combined response and 30-Hz flicker responses in 178 adult diabetics and 40 normal controls according to the recommendations of the International Society of Clinical Electrophysiology of Vision. The oscillatory potentials were extracted from the maximal combined response by high-pass filtering. The clear media and attached retina were criteria for inclusion in this study. The data were statistically analyzed with the expectation that this procedure may provide a new feature that could have some clinical significance. Timing delays occurred more frequently than amplitude reductions in the maximal combined response and flicker responses, while amplitude reductions were more common in the first and second oscillatory potentials. The hypernormal b-wave amplitude was rare. The summed amplitude of the oscillatory potentials was highly correlated with the total power of the oscillatory potentials (the frequency domain). A reduction of the second oscillatory potential amplitude was more common than a reduction of the summed amplitude or total power. The electroretinographic component that demonstrates retinal dysfunction in the earlier stage may be a valuable indicator. In the early stage, a delay in the a-wave time and a reduction in the second oscillatory potential amplitude were the most frequent abnormalities: analysis of variance demonstrated that the summed amplitude of the oscillatory potentials and second oscillatory potential amplitude and time were the most sensitive measures of the diabetic retina. Hence, the second oscillatory potential amplitude may be the most sensitive and valuable indicator representing a quantitative measure of overall retinal dysfunction.

Altered topographic expression of p21WAF1/CIP1/SDI1, bcl2 and p53 during gastric carcinogenesis

The accumulation of wild-type p53 protein results in two pathways, cell cycle G1 arrest by p21WAF1/CIP1/SDI1 and apoptosis inhibited by bcl2, which together carry out the tumor suppressor function. Since genetic alterations of p53 are frequently observed in gastric cancers, the expression of p21 and bcl2 may be altered in gastric carcinogenesis. We therefore analyzed normal mucosa, nondysplastic lesions, hyperplastic polyps, adenomas and carcinomas of the human stomach using immuno-histochemistry, polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing. In normal gastric mucosa, the expression of p21, bcl2 and p53 was topographically restricted: a) p21 expression was limited to foveolar epithelial cells; b) bcl2 and p53 expression was confined to only a few regenerative epithelial cells of the mucous neck region. In chronic gastritis or intestinal metaplasia, topographic expression became more obvious. This topographic expression was altered in hyperplastic polyps and adenomas. Hyper-plastic polyp showed an increased p21 and p53 expression with no bcl2 expression. Where as bcl2 expression increased and extended up parabasal and superficial dysplastic epithelium, p21 expression increased and was limited to surface dysplastic epithelium. Weak p53 expression was in full thickness of dysplastic epithelium. p21 and bcl2 expression in adenoma was higher than in intestinal type of carcinoma. In carcinomas, this topography was abrogated, but p53 mutation (36%) was present. There was no relationship between p53, p21 and bcl2 expression. As a result, in normal gastric epithelial cells, there was a precisely ordered topographic pattern of p21, bcl2 and wild-type p53 expression that becomes disordered during neoplasia. These results suggest that altered cell cycle and apoptosis control by wild-type p53 and its mediators appears to be an early event in gastric carcinogenesis that may facilitate tumor progression.

Identification of novel susceptibility loci for inflammatory bowel disease on chromosomes 1p, 3q, and 4q: evidence for epistasis between 1p and IBD1

The idiopathic inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), are chronic, frequently disabling diseases of the intestines. Segregation analyses, twin concordance, and ethnic differences in familial risks have established that CD and UC are complex, non-Mendelian, related genetic disorders. We performed a genome-wide screen using 377 autosomal markers, on 297 CD, UC, or mixed relative pairs from 174 families, 37% Ashkenazim. We observed evidence for linkage at 3q for all families (multipoint logarithm of the odds score (MLod) = 2.29, P = 5.7 x 10(-4)), with greatest significance for non-Ashkenazim Caucasians (MLod = 3.39, P = 3.92 x 10(-5)), and at chromosome 1p (MLod = 2.65, P = 2.4 x 10(-4)) for all families. In a limited subset of mixed families (containing one member with CD and another with UC), evidence for linkage was observed on chromosome 4q (MLod = 2.76, P = 1.9 x 10(-4)), especially among Ashkenazim. There was confirmatory evidence for a CD locus, overlapping IBD1, in the pericentromeric region of chromosome 16 (MLod = 1.69, P = 2.6 x 10(-3)), particularly among Ashkenazim (MLod = 1.51, P = 7.8 x 10(-3)); however, positive MLod scores were observed over a very broad region of chromosome 16. Furthermore, evidence for epistasis between IBD1 and chromosome 1p was observed. Thirteen additional loci demonstrated nominal (MLod > 1.0, P < 0.016) evidence for linkage. This screen provides strong evidence that there are several major susceptibility loci contributing to the genetic risk for CD and UC.

Pharmacokinetic analysis for assessing developmental toxicity of a new synthetic acetolactate synthase inhibitor, LGC-40863, in rats

Effects of O-[2,6-bis[(4,6-dimethoxy-2pyrimidinyl)oxy]benzoyl]oxime (LGC-40863) on dams and embryonic development were examined at p.o. doses of 500, 1000 and 2000 mg/kg/day on days 6 to 15 of gestation in rats. No significant maternal or embryonic toxicity was observed at any of the doses. However, external fetal anomalies including brachycephaly, microcephaly, micrognathia, agnathia, lordosis and edema were observed at an incidence of 2.2% at the lowest dosage level but not at higher dosages. Because these malformations are not common as spontaneous variations in rats, we carried out a toxicokinetic study to clarify whether the fetal anomalies at 500 mg/kg are related to LGC-40863. During multiple p.o. administrations of LGC-40863 at the same doses used in the developmental toxicity study, LGC-40863 was not detected in the systemic circulation. Moreover, 3 months of multiple dosing did not alter its plasma level. In the pregnant rats receiving 500 mg/kg on 10 consecutive days of gestation, LGC-40863 was also undetectable. However, after i.v. administration, high levels of the drug were found in plasma, and these could be described by a two-compartment model. These results demonstrate that the bioavailability of LGC-40863 is negligible. To investigate a possible relevance of metabolite(s) to the fetal anomalies, we examined excretion of radioactivity after p.o. doses of 500 and 2000 mg/kg of LGC-40863 spiked with [14C]LGC-40863. For both doses, cumulative recovery up to 72 hr was approximately 80% and 9% in feces and urine, respectively, indicating dose linearity in the elimination kinetics. Overall, these toxicokinetic data suggest that the fetal anomalies observed at 500 mg/kg are not associated with LGC-40863 but are spontaneously generated. In conclusion, LGC-40863 had neither significant maternal nor developmental toxicity at any of the doses tested for p.o. exposure.

The role of Müller's muscle reconsidered

It is a traditional teaching that the levator aponeurosis is the main transmitter of the levator palpebrae muscle. However, there are several points that raise doubts in this fundamental concept of the levator aponeurosis as being the primary interconnecting mechanism in upper lid elevation. Despite the structural integrity of the levator complex, drooping of the upper eyelids is seen to develop in situations such as Horner's syndrome and in times of excessive fatigue and sleepiness. Amid the controversy in the literature regarding the specific role of the levator aponeurosis in the lid-elevating mechanism, we have observed that the levator aponeurosis fails to make constant attachment to the tarsal plate. This has led us to speculate on the possible role of the posterior lamella - Müller's muscle - as the primary transmitter of the levator muscle action to the tarsal plate.

Aldosterone stimulates intestinal Na+ absorption in rats by increasing NHE3 expression of the proximal colon

Na+ retention by the colon in response to salt deprivation is mediated in part by the resulting secondary hyperaldosteronism. We show that experimental hyperaldosteronism, to levels seen with salt deprivation, causes an increase in the selective expression and activity of NHE3, an apically located isoform of the Na+/H+ exchange family that functions in transepithelial Na+ absorption. The effect of aldosterone on NHE3 expression is tissue specific, occurring in intestine and not in kidney. Within the intestine, these effects are regional, being observed only in proximal colon, and different in distribution from that observed with glucocorticoids, where the predominant effect occurs in ileum. Although glucocorticoids are well known to exert many effects via regulation of transcript levels, the present study demonstrates that aldosterone stimulates intestinal Na+ absorption by increasing cellular NHE3 expression, a response that is tissue and region specific.

A dynamin-like protein in Arabidopsis thaliana is involved in biogenesis of thylakoid membranes

Dynamin, a GTP-binding protein found in rat brain, plays a role in endocytosis. Suborganellar fractionation studies of Arabidopsis leaf tissue revealed that a dynamin-like protein, ADL1, is localized in the thylakoid membranes of chloroplasts. This notion was supported further by in vivo targeting experiments using an ADL1-green fluorescent fusion protein and immunogold labeling with the anti-ADL1 antibody. Transgenic plants harboring various deletion mutant genes of ADL1 had a yellow leaf phenotype where the cells had very few chloroplasts. In addition, the remaining chloroplasts appeared morphologically not fully developed. The detailed structure of the chloroplasts revealed by electron microscopy showed a greatly reduced amount of thylakoid membranes. Also, the level of thylakoid membrane proteins such as the light-harvesting complex II and CP29 was greatly reduced in these transgenic plants. When we examined the expression of the ADL1 deletion mutant genes, these genes were highly expressed at the transcriptional level. However, the mutant ADL1s were not detectable at the protein level by Western blot analysis. Moreover, the endogenous ADL1 protein level was greatly reduced in these transgenic plants, probably due to a post-transcriptional silencing effect of the transgenes. We propose, therefore, that ADLl is involved in the biogenesis of thylakoid membranes.

Cre/loxP-mediated excision and amplification of large segments of the Escherichia coli genome

The isolation and amplification of large, predetermined segments of a genome from its host have been explored. The prototype of our approach was the excisional replication of some viruses such as the lambda-lysogen. Similar machinery was used to excise and amplify large genomic segments of Escherichia coli in its host. Two loxP sequences for a site-specific recombinase Cre, together with a conditional replication origin (pi-dependent gamma-ori), were inserted into the genome by homologous recombination at predetermined sites, 50-100 kb apart. Cre and pir200 which encodes the site-specific recombinase Cre and an ori-specific replication protein pi, respectively, were also introduced into the genome. The predetermined genomic segments flanked by the loxP sequences were excised and amplified upon induction of the cre and pir200 genes which were under the control of the tet promoter. This excised and amplified DNA could be easily purified as a large plasmid. This procedure can provide an alternative to conventional cloning methods by obtaining predetermined large genomic segments directly from the original organisms. In this study, using the Cre/loxP site-specific recombination and pi/gamma-ori replication system of plasmid R6K, a procedure was devised that could isolate a large segment of the E. coli genome and demonstrated the feasibility of the procedure by excising and amplifying the 50-kb trg-narZ and 100-kb trg-hipA regions of the E. coli W3110 genome.

Expression of HuD (a paraneoplastic encephalomyelitis antigen) mRNA in lung cancer

HuD, one of the Hu antigens (HuD and HuC), was recognized in the sera of small cell lung cancer (SCLC) patients with antibody-associated paraneoplastic encephalomyelitis/peripheral sensory neuropathy (PEM/PSN). Three forms of HuD mRNA, 197, 156, 110 nucleotides are made by alternative splicing at 868-909 residues and an additional 3'-splice site. To determine the diagnostic value of the HuD expression for small cell lung cancer, we examined 4 SCLC cell lines, 9 surgically resected SCLCs, and 12 surgically resected non-SCLCs using the reverse transcriptase-polymerase chain reaction with the HuD-specific primer pairs that spanned the putative alternative 3'-splicing site and direct DNA sequencing. None of the patients were associated with PEM/PSN. A single RNA transcript (156 nucleotides) among three forms (110, 156, 197 nucleotides) of the HuD gene was an alternatively spliced at 868-909 residues in SCLC cell lines. Expression of the HuD gene was stronger in three classic cell lines, but not in a variant cell line. Two of 9 SCLCs (22%) and 3 of 12 non-SCLCs (25%) expressed only the major RNA transcript (156 nucleotides) of the HuD gene, which was alternatively spliced in the same fashion as the cell line. These results revealed that no aberrant alternative splicing occurred in SCLC not associated with PEM/PSN and the expression of HuD gene was not specific for a particular histologic subtype of human lung cancer.

Synthesis and antibacterial activities of new 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octan-2,4-dione moiety

The synthesis of a new series of 1 beta-methylcarbapenems having a 1,3-diazabicyclo[3.3.0]octane-2,4-dione moiety is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bateria are determined and the effect of substituent on the bicyclic ring as well as stereoisomerism was investigated.

Oligomycin inhibits store-operated channels by a mechanism independent of its effects on mitochondrial ATP

Inhibitors of mitochondrial oxidative metabolism have been proposed to interfere with Ca2+ influx mediated by store-operated channels (SOC), secondary to their effects on ATP production. We assessed SOC activity by 45Ca2+ influx and fluorimetric measurements of free Ca2+ or Mn2+ quench in thapsigargin-treated Chinese hamster ovary cells and Jurkat T-cells, and additionally by electrophysiological measurements of the Ca2+-release-activated Ca2+ current (Icrac) in Jurkat T-cells. Various mitochondrial antagonists were confirmed to inhibit SOC. However, the following evidence supported the proposal that oligomycin, in particular, exerts an inhibitory effect on SOC in addition to its known actions on mitochondria and Na+-pump activity: (i) the concentrations of oligomycin required to inhibit SOC-mediated Ca2+ influx or Icrac (half-inhibitory concentration approximately 2 microM) were nearly 50-fold higher than the concentrations that blocked mitochondrial ATP production; (ii) the rank order of potency of oligomycins A, B and C for decreasing SOC-mediated Ca2+ influx or Icrac differed from that known for inhibition of mitochondrial function; (iii) oligomycin blocked Icrac under voltage clamp and with intracellular Na+ and K+ concentrations fixed by dialysis from the patch pipette, arguing that the effect was not secondary to membrane polarization or pump activity; and (iv) fixing the cytosolic ATP concentration by dialysis from the patch pipette attenuated rotenone- but not oligomycin-mediated inhibition of Icrac. Oligomycin also blocked volume-activated Cl- currents, a profile common to some other known blockers of SOC that are not known mitochondrial inhibitors. These findings raise the possibility that oligomycin interacts directly with SOC, and thus may extend the known pharmacological profile for this type of Ca2+-influx pathway.

Chondromalacia of the knee: evaluation with a fat-suppression three-dimensional SPGR imaging after intravenous contrast injection

Twenty-one MRI studies with a fat-suppression three-dimensional spoiled gradient-recalled echo in a steady state (3D SPGR) pulse sequence after intravenous contrast injection were evaluated to assess the accuracy in depicting chondromalacia of the knee. On the basis of MR images, chondromalacia and its grade were determined in each of five articular cartilage regions (total, 105 regions) and then the results were compared to arthroscopic findings. The sensitivity, specificity, and accuracy of MRI were 70%, 99%, and 93%, respectively. MR images depicted 7 of 11 lesions of arthroscopic grade 1 or 2 chondromalacia, and seven of nine lesions of arthroscopic grade 3 or 4 chondromalacia. The cartilage abnormalities in all cases appeared as focal lesions with high signal intensity. Intravenous contrast-injection, fat-suppression 3D SPGR imaging showed high specificity in excluding cartilage abnormalities and may be considered as an alternative to intra-articular MR arthrography when chondromalacia is suspected.