Diffusion-weighted magnetic resonance imaging in Wernicke's encephalopathy

OBJECTIVE

To report diffusion-weighted imaging (DWI) findings and postulate the pathogenic mechanism of Wernicke's encephalopathy (WE).

PATIENT

A 47-year-old-woman presented with altered consciousness, ophthalmoplegia, and ataxia. DWI revealed the abnormal signal changes in periaqueductal gray matter, mamillary bodies and bilateral medial thalami. Apparent diffusion coefficient (ADC) map revealed the high signal intensity lesions in bilateral medial thalami, suggestive of vasogenic edema. The abnormal signal intensity lesions disappeared on follow-up imaging with clinical improvement.

CONCLUSIONS

Vasogenic edema plays an important role in the pathogenesis of WE and can be reversed by proper management. DWI findings in the early stage of WE may provide useful information about the prognosis.

Liquid chromatographic resolution of biphenyl dimethyl dicarboxylate (DDB) and its analogues on a chiral stationary phase

Racemic biphenyl dimethyl dicarboxylate (DDB) and its analogues have been successfully resolved on a commercial HPLC chiral column, (3R,4S)-Whelk-O 1. In general, cyclic amide analogues of DDB, which were derived from pyrrolidine or piperidine, showed greater enantioselectivity and greater retention than the corresponding N,N-dialkyl amide or N-alkyl amide or ester analogues. From these results, it was concluded that the carbonyl oxygen of the DDB analogues plays an important role as a hydrogen bond acceptor, though the steric bulkiness of the amide functionality of DDB analogues may be another factor governing chiral recognition. The conformational stability of the two enantiomers of DDB and its analogues was also found to be high enough for the two enantiomers to be resolvable on (3R,4S)-Whelk-O 1.

Synergy of Bacteroides fragilis and Escherichia coli in the induction of KC gene expression in mouse peritoneal tissues

B. fragilis induces cytokine expression, which can serve as a host signal leading to inflammatory reaction and abscess formation in the peritoneal cavity. We assessed the hypothesis that enteric bacteria may alter the B. fragilis-induced expression of KC genes in mouse peritoneal tissues (MPT). After C57BL/6 mice were inoculated with abscess-forming mixture containing B. fragilis in the presence or absence of E. coli, RNA was extracted from MPT. Expression of KC mRNA was quantified using reverse-transcription polymerase chain reaction and standard RNA. KC and TNFalpha proteins were measured by enzyme-linked immunosorbent assay. KC mRNA in MPT was upregulated following inoculation of B. fragilis and this was paralleled by increased KC protein secretion. When the mice were co-infected with E. coli and B. fragilis intraperitoneally, there was a synergistic increase in the expression of KC of MPT. Co-infection with L. acidophilus and B. fragilis downregulated KC mRNA expression, but co-infection with E. faecalis and B. fragilis synergistically increased KC expression in the infected MPT. Inhibition of TNFalpha production could downregulate KC expression in mixed infected MPT. These results suggest that enteric bacteria may significantly affect the KC signal produced by the host peritoneal cavity in response to B. fragilis infection.

A case of primary adenosquamous carcinoma of the liver presented with liver abscess

Primary adenosquamous carcinoma of the liver is a very rare type of cholangiocarcinoma and is defined as a cancer containing both squamous and adenomatous components in the same lesion. Recently, we experienced a primary adenosquamous carcinoma of the liver presented as liver abscess. A 63-year-old man was presented with a 4-day history of fever and chill. The radiologic study showed a 4 cm-sized, central hypoattenuated mass with peripheral rim enhancement in the left lobe of the liver. Ultrasonography-guided aspiration and biopsy suggested an adenocarcinoma with abscess in the liver. At laparotomy, the tumor occupied the left lobe of the liver and invaded the right diaphragm. An extended left lobectomy and a partial excision of the involved diaphragm were done. Grossly, the tumor was 6 x 5 x 5 cm in size and had an eccentric necrosis. Microscopically, the tumor was composed of adenocarcinoma and squamous cell carcinoma with a transitional area.

Nuclear factor-kappa B plays a major role in the regulation of chemokine expression of HeLa cells in response to Toxoplasma gondii infection

Toxoplasma gondii infection results in an infiltration of immune cells. The mechanisms responsible for triggering inflammatory cell infiltration in T. gondii infection are not fully understood. We report that T. gondii-infected HeLa cells induced nuclear factor-kappa B (NF-kappaB) activation and increased the expression of interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) mRNA. An inhibitor of NF-kappaB activation, calpain-1 inhibitor, blocked the chemokine secretion induced by live T. gondii. Activation of the IL-8 and NF-kappaB transcriptional reporters was suppressed in cells co-transfected with IkappaB kinase beta and the IkappaBalpha super-repressor plasmids. Moreover, the addition of IL-1alpha increased NF-kappaB activation and IL-8 mRNA expression in T. gondii-infected HeLa cells. These results suggest that NF-kappaB is a central regulator of the chemokine response in T. gondii-infected human epithelial cells and that chemokine IL-8 and MCP-1 secretion might be involved in the pathogenesis of T. gondii, via the recruitment of neutrophils, monocytes, and lymphocytes.

Association of p53 and BCL-2 expression with Epstein-Barr virus infection in the cancers of head and neck

BACKGROUND

Reports that have both evaluated the site-specific Epstein-Barr virus (EBV) infection and compared it with the expression of the EBV-related proto-oncogenes and tumor suppressor genes in the various cancers of head and neck are scarce.

METHODS

Thirty-eight nasopharyngeal carcinoma (NPC) cases, 32 oropharyngeal or hypopharyngeal carcinoma (OPC/HPC) cases, and 93 laryngeal carcinoma (LC) cases were evaluated with in situ hybridization on EBV-encoded small RNA (EBER) and immunohistochemical assessments of the p53, bcl-2, and epidermal growth factor receptor (EGFR) by use of formalin-fixed paraffin-embedded tissue array slides.

RESULTS

The expression of viral EBERs was observed in more than two thirds (71.1%) of the NPC cases. In contrast, only 1 case of OPC and none of the HPC or LC cases exhibited EBV positivity. In the nonkeratinizing NPC, the EBV positivity was significantly associated with both frequent p53 overexpression (p =.033) and bcl-2 expression (p =.001). In the EBV-positive nonkeratinizing NPC, a correlation between p53 overexpression and the tumor infiltration lymphocyte (TIL) density was noted (p =.012).

CONCLUSIONS

A site-specific expression of viral EBER was demonstrated in the head and neck cancers, which suggests an important role for both p53 and bcl-2 in the carcinogenesis of an EBV-infected NPC. The correlation between p53 overexpression and the TIL density in the EBV-infected NPC suggests that the product of a lymphoepithelial interaction, such as A20, can induce a dysfunctional p53 protein.

Requirement of de novo protein synthesis for aminopterin-induced apoptosis in a mouse myeloma cell line

Cells synthesize nucleotides through de novo and salvage pathways that require the activities of dihydrofolate reductase (DHFR) and hypoxanthine-guanine phosphoribosyltransfease (HGPRT), respectively. Aminopterin, an inhibitor of dihydrofolate reductase, has been demonstrated to allow HGPRT(-) cells to be negatively selected. However, the pathway by which aminopterin leads to cell death remains to be clarified. In this study, we characterized features of cellular responses induced by aminopterin treatment in P3-X63-Ag8.653, a mouse HGPRT(-) myeloma cell line. Upon treatment with aminopterin, the cells readily underwent an apoptotic process, as assessed by DNA fragmentation assay and electron microscopic analysis. Aminopterin-induced apoptosis was drastically reduced by addition of actinomycin D and cycloheximide, indicating that active RNA and protein synthesis is required for the apoptotic effect of aminopterin. Interestingly, the induction of c-myc gene expression preceded the activity of DNA fragmentation in aminopterin-treated cells. Taken together, these results suggest that cells deficient in the salvage pathway of purine biosynthesis are susceptible to aminopterin-induced apoptosis that requires de novo synthesis of proapoptotic factors, including Myc oncoprotein.

Differential display analysis of gene expression altered by ras oncogene

The goal of the signal transduction pathways, such as those controlled by Ras, is in large part to ensure highly stringent regulation of the target genes in the nucleus, which are collectively responsible for the signal output, or phenotypes, of the cell. Understanding of the Ras effect ultimately requires the identification of these downstream target genes. Reverse genetic approaches would trace back the pathways by which they are regulated by Ras. While newer methods such as DNA microarray are emerging, differential display has allowed the identification of a greater number of differentially expressed genes than have been cloned by all the other methods combined, based on Medline search. Much of this success has been attributed to its simplicity (RT-PCR and DNA-sequencing gel) and versatility (compare more than two RNAs for both up- and downregulated genes). It has become obvious that finding the genes by either differential display or DNA microarray is only the first step toward the understanding of biological problems under investigation. It is hoped that finding the right genes through careful experimental designs, such as outlined here, will narrow down the number of relevant genes and increase the odds for solving the puzzles of nature, such as ras.

Sequence variations of hepatitis B virus promoter regions in persistently infected patients

The HBV in the sera of two chronic active hepatitis patients were analyzed for the promoter sequence heterogeneity. In most cases, the proportion of any particular clone in the total viral populations was less than 50%, showing high mutation rates. In contrast, promoter sequences of HBV from asymptomatic carriers revealed only a few point mutations with no deletions. HBV in chronic patient harbored variants with multiple mutations throughout promoters including 1762 (A-to-T), 1764 (G-to-A) double mutation in C promoter and deletions near CCAAT site in S promoter. Unlike other three promoter regions, C, pre-S1 and S, of HBV which revealed a high level of sequence heterogeneity, the X promoter region (from nt985 to 1430) showed little sequence heterogeneity within a patient. However, the predominant viral clones in two patients were quite different from each other. In addition to mutations in promoter regions, a deletion mutation in the translation start codon was also found in pre-S1 gene. The results in this report indicate that the mutation rates are not the same in all four promoters and that one of the strategies for maintaining persistent infection could be through mutations in viral promoters which then impair the balance of viral gene expressions.

In situ hybridization of Epstein-Barr virus in tumor cells and tumor-infiltrating lymphocytes of the gastrointestinal tract

Unlike gastric carcinoma, associations of the Epstein-Barr virus (EBV) with carcinomas of other sites in the gastrointestinal tract have not yet been clarified. To elucidate these associations, we investigated the presence of EBV in 142 cases of esophageal carcinoma, 107 cases of ampulla of Vater carcinoma, and 274 cases of colorectal carcinoma in Korean patients using EBV-encoded small RNAs (EBER)-in situ hybridization (ISH). In all cases, none of the tumor cells showed a positive signal, indicating that EBV is not generally related to the carcinogenesis of these cancers. Some EBV-positive tumor-infiltrating lymphocytes (TILs) were found in 8 of 142 cases (5.6%) of esophageal carcinoma, 8 of 107 cases (7.5%) of ampulla of Vater cancer, and 35 of 274 cases (12.8%) of colorectal carcinoma. For comparison, EBER-ISH was performed in consecutive gastric carcinomas; the EBER signal on tumor cells was observed in 17 of 306 cases (5.6%), and EBV-positive TILs were seen in 31 of the 289 cases (10.7%). There was no statistically significant difference in the frequencies of cases with EBV-positive TILs among the gastrointestinal tract cancers. We suggest that the reservoir lymphocytes carrying EBV, like other inflammatory cells, are able to reach anywhere, and that the chance for an epithelial cell to be exposed to EBV is similar at different sites of the gastrointestinal tract, regardless of its carcinogenic effect on the epithelial cell. HUM PATHOL 32:297-301.

Polarized secretion of CXC chemokines by human intestinal epithelial cells in response to Bacteroides fragilis enterotoxin: NF-kappa B plays a major role in the regulation of IL-8 expression

Enterotoxigenic B. fragilis, which produces a approximately 20 kD heat-labile toxin (BFT), has been associated with diarrhoeal diseases and mucosal inflammation. To determine if epithelial cells can contribute to BFT-induced inflammation, we assessed the expression of CXC chemokines by BFT-stimulated human intestinal epithelial cells. BFT stimulation increased expression of the neutrophil chemoattractant and activators ENA-78, GRO-alpha, and IL-8. Up-regulated chemokine mRNA expression was paralleled by increased protein levels. Activation of the IL-8 and NF-kappa B transcriptional reporters was inhibited in cells cotransfected with the I kappa B kinase beta and IkB alpha superrepressor plasmids. Whereas lactate dehydrogenase, which was used to monitor cell lysis, was released predominantly from the apical surface, CXC chemokines were predominantly secreted from the basolateral surface of BFT-treated epithelial cells. The basolateral secretion of CXC chemokines from BFT-stimulated colon epithelial cells suggests that these chemokines can contribute to the inflammatory cell infiltrate in the underlying intestinal mucosa.

Multicolor fluorescent differential display

Differential display and DNA microarray have emerged as the two most popular methods for gene expression profiling. Here, we developed a multicolor fluorescent differential display (FDD) method that combines the virtues of both differential display in signal amplification and DNA microarray in signal analysis. As in DNA microarray, RNA samples being compared can be labeled with either a red or green fluorescent dye and displayed in a single lane, allowing convenient scoring and quantification of the differentially expressed messages. In addition, the multicolor FDD has a built-in signal proofreading capability that is achieved by labeling each RNA sample from a comparative study with both red and green fluorescent dyes followed by their reciprocal mixings in color. Thus, the multicolor FDD provides a platform upon which a sensitive and accurate gene expression profiling by differential display can be automated and digitally analyzed. It is envisioned that cDNAs generated by the multicolor FDD may also be used directly as probes for DNA microarray, allowing an integration of the two most widely used technologies for comprehensive analysis of gene expression.

Preparation and evaluation of biphenyl dimethyl dicarboxylate microemulsions for oral delivery

To improve the solubility and bioavailability of poorly water-soluble biphenyl dimethyl dicarboxylate (BDD), a drug used in treating liver diseases, a premicroemulsion concentrate composed of oil, surfactant, and cosurfactant for oral administration of BDD was prepared, and its physicochemical properties and the pharmacokinetic parameters of BDD were evaluated. Among the non-ionic surfactants and oils studied, Tween 80, which led to the highest solubility of BDD (109.7 microg/ml), and Neobee M-5((R)) were chosen for preparing a premicroemulsion concentrate. At the 2:1 ratio of Tween 80 to Neobee M-5((R)), the solubility of BDD increased 7-fold compared with that at the ratio of 1:4. The solubility of BDD was further improved by the addition of triacetin used as a cosurfactant. Droplet size of BDD microemulsion comprising Tween 80 and Neobee M-5((R)) at the ratio of 2:1, and 35% of triacetin, was kept constant both in distilled water and artificial gastric fluid without pepsin (pH 1.2) throughout 120-min incubation period. BDD in premicroemulsion concentrate rapidly dissolved whereas the mixture of BDD and calcium-carboxymethylcellulose (Ca-CMC) (2:1) and BDD powder hardly dissolved during 120-min incubation. About 50% of BDD in premicroemulsion concentrate dissolved within 10 min. AUC(0-->24 h) and the mean maximum plasma level (C(max)) of BDD after oral administration of premicroemulsion concentrate in rats were 5- and 9.8-fold higher, respectively, than those of BDD with Ca-CMC. These results demonstrate that premicroemulsion concentrate of BDD composed of Tween 80 and Neobee M-5((R)) at the ratio of 2:1, and 35% of triacetin, greatly enhances the bioavailability of BDD after the dose, possibly due to the increase in solubility and immediate dispersion of drug in the gastrointestinal tract. Thus, this system may provide a useful dosage form for oral intake of a water-insoluble drug, BDD.

Naturally acquired antibody responses to the C-terminal region of merozoite surface protein 1 of Plasmodium vivax in Korea

We expressed a protein in Saccharomyces cerevisiae in order to evaluate the humoral immune responses to the C-terminal region of the merozoite surface protein 1 of Plasmodium vivax. This protein (Pv200(18)) had a molecular mass of 18 kDa and was reactive with the sera of individuals with patent vivax malaria on immunoblotting analysis. The levels of immunoglobulin M (IgM) and IgG antibodies against Pv200(18) were measured in 421 patients with vivax malaria (patient group), 528 healthy individuals from areas of nonendemicity (control group 1), and 470 healthy individuals from areas of endemicity (control group 2), using the indirect enzyme-linked immunosorbent assay (ELISA) method. To study the longevity of the antibodies, 20 subjects from the patient group were also tested for the antibody levels once a month for 1 year. When the cutoff values for seropositivity were determined as the mean + 3 x standard deviation of the antibody levels in control group 1, both IgG and IgM antibody levels were negative in 98.5% (465 of 472) of control group 2. The IgG and IgM antibodies were positive in 88.1% (371 of 421) and 94.5% (398 of 421) of the patient group, respectively. The IgM antibody became negative 2 to 4 months after the onset of symptoms, whereas the IgG antibody usually remained positive for more than 5 months. In conclusion, indirect ELISA using Pv200(18) expressed in S. cerevisiae may be a useful diagnostic method for vivax malaria.

Factors affecting insertion time and patient discomfort during colonoscopy

BACKGROUND

Successful colonoscopy depends on insertion of the instrument to the cecum, precise observation, and minimal patient discomfort during the procedure. The aim of this prospective study was to determine whether certain variables are associated with insertion time and patient discomfort during colonoscopy.

METHODS

Nine hundred nine consecutive colonoscopic examinations performed by a single endoscopist in patients without obstructive disease of the colorectum were analyzed. Four liters of Colonlyte (Taejun, Seoul, Korea) were used for bowel cleansing, and meperidine (25 mg) was administered intramuscularly 10 minutes before the procedure. The degree of patient discomfort was assessed using a 5-level Likert scale.

RESULTS

Among 909 study patients, colonoscopy was completed to the cecum in 876 patients (96.4%). The adjusted completion rate was 98% and mean insertion time for complete colonoscopy was 6.9+/-4.2 minutes. Colonoscopy caused less patient discomfort than barium enema or esophagogastroduodenoscopy. Multivariate logistic regression analysis demonstrated that inadequate bowel cleansing, advanced age, and constipation as an indication are independent factors associated with prolonged insertion time (>10 minutes). Female gender was the only independent factor associated with significant discomfort (> or = level 4) during colonoscopy.

CONCLUSIONS

Among the factors affecting insertion time and patient discomfort during colonoscopy, unsatisfactory bowel preparation was the only correctable factor.

Hydrocortisone enhances allergen-specific IgE production by peripheral blood mononuclear cells from atopic patients with high serum allergen-specific IgE levels

BACKGROUND

Although there is convincing evidence that human B cells can be induced to produce IgE by a combination of interleukin 4 (IL-4) and hydrocortisone (HC) in atopic subjects, it is still uncertain if this performs the same functions in allergen-specific IgE synthesis.

OBJECTIVE

This study was designed to investigate the differences of IgE regulation between atopics and nonatopics, interactions of HC with IL-4, and the correlation between in vitro total IgE, allergen-specific IgE synthesis and serum IgE levels.

METHODS

Peripheral blood mononuclear cells (PBMCs) from 16 atopic asthma patients sensitive to Dermatophagoides farinae and seven nonatopic controls were cultured with IL-4 and/or HC. Total IgE and D. farinae-specific IgE in culture supernatant were measured by ELISA and FAST.

RESULTS

IL-4 increased total IgE synthesis in PBMCs from both atopics and nonatopics, whereas, HC had this effect only in some atopics who showed spontaneous IgE production in vitro. HC acted synergistically with IL-4 in total IgE synthesis. Their effects were more remarkable in cases with lower total serum IgE levels. PBMCs from eight of 16 atopics produced D. farinae-specific IgE in vitro either spontaneously or by IL-4 and/or HC. HC had more profound effects than IL-4 in these patients. They also showed higher total IgE synthesis by HC, and higher specific serum IgE levels than the others. IL-4 and/or HC did not induce any D. farinae-specific IgE synthesis by PBMCs from nonatopics.

CONCLUSION

HC had a more profound effect than IL-4 on the induction of D. farinae-specific IgE synthesis in atopic patients with high serum allergen specific IgE levels. Further studies to determine the causes of these effects, such as the presence of long lived allergen specific B cells as the result of the priming effect of IL-4 in vivo, may be needed.

Hemophilic pseudotumor of the ulna treated with low dose radiation therapy: a case report

We report a case of hemophilic pseudotumor in the ulna of a 6-year-old boy treated with radiation therapy. A total dose of 900 cGy in 6 fractions was given in 6 consecutive days. Progression of cystic changes was halted within a month. New bone formation and trabeculation were found on the 4th month. Complete healing of the lesion and bony replacement were found on the 12th month. The patient was followed up to 72 months and there was no evidence of recurrence and no bone growth disturbance. Radiation therapy can be an effective alternative modality in treating hemophilic pseudotumor.

Mutations and amplification of oncogenes in endometrial cancer

Alterations in oncogenes are critical steps in the development of endometrial cancer. To investigate the potential clinical relevance of the amplification of the oncogenes c-erbB2, c-myc, and int-2 and the mutation of K-ras in endometrial cancer, 112 tumors were examined using PCR-based fluorescent DNA technology. Amplification of the three oncogenes and the mutation of K-ras were correlated with age, tumor size, lymph node status, metastases, stage, histological types, grade, steroid hormone receptor expression (estrogen receptor, ER; progesterone receptor, PgR), family history of cancer, previous history of cancer or precursor lesions, and previous history of hormone replacement therapy. Oncogene amplification of c-erbB2 was detected in 18.9%, of c-myc in 2.7% and of int-2 in 4.2%, and K-ras mutation in 11.6%. No significant correlations could be detected between amplification of c-erbB2 and any of the other parameters. Mutation of K-ras is associated with positive expression of PgR. This might indicate that mutation and activation of K-ras are involved in the development of hormonal independence in endometrial cancer.

Adenosine triphosphate-induced heterologous desensitization of endothelin-1- and glutamate-evoked calcium increases in cultured rat cortical astrocytes

In rat cortical astrocytes, we investigated the occurrence of cross-talks between purinoceptor and endothelin (ET) receptor, or glutamate receptor. The treatments of adenosine triphosphate (ATP), ET-1, and glutamate induced the increase of intracellular calcium level in the astrocytes. In repetitive additions of ATP to astrocytes, the second application of ATP exhibited comparable amplitude of calcium response, but the stimulation with ATP completely blocked subsequent ET-1- or glutamate-evoked calcium responses showing complete heterologous desensitization. In contrast, ET-1 and glutamate failed to desensitize the response elicited by ATP. Preincubation with sphingosine, a protein kinase C (PKC) inhibitor, reversed the ATP-induced desensitization of ET-1- and glutamate-evoked calcium responses. Taken together, these results demonstrate the resistance of purinoceptor to homologous desensitization, and unidirectional desensitization between ATP and other receptors such as ET and glutamate receptors, suggesting a dominant role of purinoceptor in modulating calcium signal of astrocytes.

Building a common feature hypothesis for thymidylate synthase inhibition

A set of 21 highly flexible competitive inhibitors of thymidylate synthase (TS; EC 2.1.1.45) covering a wide activity range (IC50 = 6 nM-100 microM) has been investigated by three-dimensional quantitative structure-activity relationship (3D-QSAR). CATALYST was used to generate three-dimensional hypotheses to study the common interaction features among a set of thymidylate synthase inhibitor. The verification of the hypothesis was achieved by using the molecules outside the training set.

The influence of gastrectomy on the change of bone metabolism and bone density

OBJECTIVES

Abnormalities of bone metabolism could be followed in gastrectomized patients as a late complication. Nowadays, many biochemical and radiologic measurements are applied to detect these abnormalities. The aim of our study is to determine the valuable parameter as an appropriate screening test during long-term follow-up periods and define the usefulness of new biochemical markers for bone metabolism by comparing with traditional markers.

METHODS

Fifteen patients who had undergone partial gastrectomy were chosen randomly and fifteen healthy controls were compared. Then, several biochemical and radiologic tests were measured. We excluded subjects who proved to have other causes of bone metabolism abnormalities. Ten patients and 10 controls were finally selected.

RESULTS

Comparing the data with those of a corresponding control group, the lumbar bone density measured by quantitative computed tomography (QCT) was statistically significantly lower in the patient group (p < 0.01). The urinary deoxypyridinoline, a biochemical marker for bone resorption, was statistically higher in the patient group (p < 0.025). Osteocalcin, Procollagen I C-terminal peptide (PICP) and Type I collagen C-terminal telopeptide (ICTP) were slightly but not significantly higher in the patient group. The serum parathyroid hormone (PTH) and 25-hydroxy vitamin D levels were similar in both groups.

CONCLUSION

We could suggest that urinary deoxypyridinoline and QCT are appropriate parameters as screening tests for the detection of bone metabolism abnormalities in gastrectomized patients during long-term follow-up. Urinary deoxypyridinoline may be a simple and rapid test which could replace cumbersome 24-hour urinary hydroxyproline.

Mechanism of silica- and titanium dioxide-induced cytotoxicity in alveolar macrophages

Particles can cause cytotoxicity in pulmonary alveolar macrophages (AM). Several mechanisms to explain this cytotoxicity have been suggested. However, the exact mechanism of particle-induced cytotoxicity in AM remains to be established. Silica and TiO2 produced a concentration-dependent cytotoxicity as evidenced by loss of cell viability and fall in ATP levels. While silica induced a greater cytotoxicity, TiO2 produced a higher reduction in ATP levels. Silica increased the release of LDH, but TiO2 did not affect enzymatic release. TiO2 suppressed succinate-triggered oxygen consumption, whereas silica did not markedly change the effect of succinate on oxygen consumption. Polyinosinic acid (PI), a ligand of the scavenger receptor, inhibited the TiO2-induced fall in ATP content, but could not prevent the effect of silica on cellular ATP content. Data suggest that silica and TiO2 can induce cytotoxicity in AM, probably through different mechanisms.

Rapid degradation of PrxI and PrxII induced by silica in Rat2 cells

Peroxidases of the peroxiredoxin (Prx) family catalyze the reduction of H(2)O(2) and lipid peroxides. The effects of H(2)O(2), 12-O-tetradecanoylphorbol 13-acetate (TPA), and silica on the abundance of two cytosolic isoforms of Prx (PrxI and PrxII) were examined in Rat2 cells. TPA induces the production of reactive oxygen species (ROS) in various mammalian cell types, and silica induces the production of ROS in Rat2 cells. Whereas H(2)O(2) and TPA did not affect the concentration of PrxI or Prx II, silica triggered a rapid degradation of both Prx enzymes. Silica also induced degradation of the NF-kappaB inhibitor IkappaB-alpha. N-Acetylcysteine and diphenyleneiodonium, both of which inhibit the accumulation of intracellular ROS, each blocked silica-induced degradation of IkappaB-alpha but had no effect on that of the Prx enzymes, suggesting that ROS do not contribute to Prx proteolysis. The silica-induced degradation of Prx enzymes was also insensitive to the proteasome inhibitors MG132 and lactacystin, whereas IkappaB-alpha proteolysis was completely blocked by these inhibitors. Experiments with the Ca(2+) ionophore A23187 indicated that a Ca(2+)-dependent protease such as calpain might contribute substantially to silica-induced degradation of PrxII, but only moderately to that of PrxI. These results indicate that silica increases cellular oxidative stress not only by inducing ROS production, but also by triggering the degradation of Prx enzymes that are responsible for elimination of cellular ROS. Such aggravated oxidative stress might be important in the initial pathogenesis of silica-associated pulmonary diseases.

Phenidone attenuates oxygen/glucose deprivation-induced neurotoxicity by antioxidant and antiapoptotic action in mouse cortical cultures

The abrupt elevation in the levels of cyclooxygenase or lipoxygenase metabolites of arachidonic acid during cerebral ischemia contributes to neuronal injury. Recently, evidence has accumulated that both excitotoxic and apoptotic features can coexist in ischemia models in vitro and in vivo. In this study, we evaluated whether phenidone, an inhibitor of both cyclooxygenase and lipoxygenase, can provide protection against excitotoxin- or ischemia-induced neurotoxicity, including the staurosporine apoptosis model, in mouse cortical cultures. We examined the protective effect of phenidone against free radical injuries induced by arachidonic acid, hydrogen peroxide, xanthine/xanthine oxidase, Fe2+/ascorbic acid. Pre- and post-treatment with phenidone (300 microM for 24 h) moderately attenuated the neuronal injury induced by 50 microM kainate and oxygen/glucose deprivation (45 min) by 33% and 50%, respectively. It had no effect on NMDA induced injury (150 microM for 5 min). The maximum dose of phenidone (300 microM) reduced the oxidative injury induced by arachidonic acid (71% inhibition), hydrogen peroxide (95% inhibition), xanthine/xanthine oxidase (57% inhibition), and Fe2+/ascorbic acid (99% inhibition) neurotoxicity. Phenidone (300 microM) decreased staurosporine (100 nM)-induced apoptosis to 30%. These results suggest that phenidone may contribute to neuronal survival by modulating oxidative stress, which is involved in the excitotoxic and apoptotic processes occurring under ischemic conditions.

Silica-induced generation of reactive oxygen species in Rat2 fibroblast: role in activation of mitogen-activated protein kinase

Exposure to silica has been associated with progressive pulmonary inflammation and fibrosis. While the fibroblasts play an important role in the pathogenesis of silicosis, the direct interaction between silica and fibroblasts is poorly understood. We observed that silica particles stimulated intracellular ROS generation in Rat2 fibroblast, evidenced by DCFH oxidation. Silica-induced DCFH oxidation was inhibited by catalase and DPI, a flavoenzyme inhibitor. Additionally, the time course of elevation of the intracellular ROS was paralleled by the increases of MEK and ERK phosphorylation. Silica-induced ERK phosphorylation was also effectively attenuated by catalase and DPI. However, SOD enhanced the silica-induced ERK phosphorylation, indicating a role for H(2)O(2) in ERK activation. Furthermore, ERK and MEK phosphorylation are reproduced by H(2)O(2) treatment. Taken together, these results demonstrate that silica stimulates ROS production via flavoenzyme-dependent mechanism in Rat2 fibroblasts and the H(2)O(2), in turn, serves as a signal transduction element in activating MEK-ERK pathway.

Molecular interactions in ribose transport: the binding protein module symmetrically associates with the homodimeric membrane transporter

The Escherichia coli high-affinity ribose transporter is composed of the periplasmic ribose-binding protein (RBP or RbsB), the membrane component (RbsC) and the ATP-binding protein (RbsA). In order to dissect the molecular interactions initiating the transport process, RbsC suppressors for transport-defective rbsB mutations were isolated. These suppressors are localized in two regions of RbsC, which are allele-specific to N- or C-terminal domain mutations of RBP, suggesting that there are two distinct regions of RbsC, each interacting with one of the two domains of RBP. To demonstrate that these two regions provide a homodimeric binding surface for RBP we constructed a dimeric rbsC in which two genes are joined tandemly from head to tail with the addition of a linker. The dimeric RbsC protein is stable and functional in growth and ribose uptake. By exploiting the allele specificity between the domain-specific mutations and their suppressors, we generated all mutation-suppressor combinations in a single rbsB plus the dimeric rbsC genes. Their phenotypes are consistent with the proposal that the binding protein module interacts symmetrically with homodimeric RbsC. The mode of association proposed here for the ribose transport components could be extended to other ABC transporters with similar structural organizations.

Negative conversion of antimitochondrial antibody in primary biliary cirrhosis: a case of autoimmune cholangitis

Autoimmune cholangitis is a clinical constellation of chronic cholestasis, histological changes of chronic nonsuppurative cholangitis and the presence of autoantibodies other than antimitochondrial antibody (AMA). It is uncertain whether this entity is definitely different from AMA positive primary biliary cirrhosis (PBC), though it shows some differences. We report a case of autoimmune cholangitis in a 59-year-old woman, who had been previously diagnosed as AMA-positive PBC associated with rheumatoid arthritis, has been converted to an AMA-negative and anticentromere antibody-positive PBC during follow-up. The response to ursodeoxycholic acid treatment is poor except within the first few months, but prednisolone was dropping the biochemical laboratory data.

Human immune response to a Pseudomonas aeruginosa outer membrane protein vaccine

In order to evaluate in humans the safety and immunogenicity of a Pseudomonas aeruginosa vaccine composed of outer membrane proteins (OMPs), CFC-101, we carried out a phase I/IIa clinical trial in healthy male volunteers. Groups of six volunteers were immunized either subcutaneously (s.c.) or intramuscularly (i.m.) with three dosages of the vaccine three times at 7-day intervals. The vaccine was well tolerated by volunteers. Local reactions in the injection sites were generally mild and transient. Significant increases in OMP-specific antibody were observed in both route groups after vaccinations but was higher in the i.m.-immunized group, where vaccination with 0.5 or 1.0 mg doses yielded 100% seroconversion. The specificity of the induced antibodies to P. aeruginosa OMP was demonstrated by western blot analysis and immunoprecipitation assay. An increase in Clq-binding capacity and ability to confer mice protection from lethal challenges with P. aeruginosa indicated the protective efficacy of the elicited antibodies. Based on these data, we concluded that the P. aeruginosa OMP vaccine is safe and effective in humans with an optimal dose of 0.5 and 1.0 mg and that i.m. is the better route than s.c. for this vaccine.

Chondrocyte differentiation in a rat mesenchymal cell line

We used a combination of morphologic and histochemical methods to demonstrate that rat calvaria-derived mesenchymal cells, RCJ 3.1C5. 18, in culture progress through the differentiation pathway exhibited by chondrocytes in the endochondral growth plate. The cells were grown either as monolayer or suspension cultures. Subconfluent monolayer cultures did not express markers typical of chondrocyte phenotypes. However, after reaching confluency the cells formed nodules of chondrocytic cells separated by cartilage-appearing matrix and encapsulated by fibroblast-like cells. Suspension culture produced cell aggregates with similar characteristics. Matrix in both the nodules and aggregates stained for collagen Types II and XI and aggrecan, and some cells displayed a distinctive pericellular matrix that stained for Type X collagen. Mineralization was evident in older cultures. By electron microscopy, most cells in the aggregates appeared as typical chondrocytes. However, some larger cells were surrounded by a "mat" of matrix comprised of hexagonal arrays of dense nodules interconnected by a filamentous network. Immunogold localization confirmed the presence of collagen Type X in this matrix. Analysis of markers of chondrocyte differentiation and terminal differentiation over time showed that these markers were acquired sequentially over 2 weeks of culture. This model system will be useful to study the regulation of various steps in the chondrocyte differentiation pathway.

Distributional patterns of phospholipase C isozymes in rat kidney

As the first step to investigate the physiological function of phospholipase C (PLC), we determined the distribution patterns of PLC isozymes in normal rat kidneys using Western blotting analysis and immunohistochemistry. Western blotting analysis was performed in four regions (cortex, outer stripe and inner stripe of the outer medulla, and the inner medulla). PLC-beta1 and beta3 were detected in the inner stripe of the outer medulla and the inner medulla. PLC-gamma1 was distributed homogeneously along the corticomedullary axis. PLC-gamma2 was observed in the medulla and PLC-delta1 showed a gradual increase from the cortex to the inner medulla. In contrast, no PLC-beta4 was detected in all regions. On immunohistochemistry, the immunoreactivities to PLC antibodies were observed as follows: PLC-beta1, from the thick ascending limb (TAL) to the inner medullary collecting tubule (IMCT); PLC-beta3, in the glomerulus (Glm), the ascending thin limb (ATL) and the collecting tubule; PLC-beta4, Glm, the proximal convoluted tubule (PCT), ATL, the distal convoluted tubule, the connecting tubule, and the collecting tubules; PLC-gamma1, PCT, TAL and IMCT; PLC-delta1, homogeneously from PCT to IMCT. PLC-beta3 immunoreactivities were detected in the nuclei of the TAL, ATL, outer medullary collecting tubule (OMCT) and IMCT. PLC-beta4 and gamma2 were observed in Glm, MTAL, ATL, OMCT and IMCT. These results suggest the intrarenal site-specific existence of PLC isozymes that may regulate kidney functions through the PLC-mediated signal transductions.

Attenuation of renomedullary phospholipase C isozyme, PLC-delta 1, in spontaneously hypertensive rats

The distributional patterns of PLC isozymes within the kidney were investigated using spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats at 4 and 12 weeks of age. PLC-beta 1, PLC-beta 3 and PLC-delta 1 quantified by Western blot analysis, were present in the highest concentrations in the inner medulla of rats at both 4 and 12 weeks of age. On the other hand, PLC-beta 4, PLC-gamma 1 and PLC-gamma 2 were distributed almost equally among the regions for the rats of both ages. When compared with WKY rats at 12 weeks of age, the amounts of PLC-beta 1, PLC-beta 3, PLC-gamma 1, PLC-gamma 2, and PLC-delta 1 in the inner medulla of SHRs were significantly lower, and the amount of PLC-delta 1 in the inner stripe of the outer medulla was also significantly lower. Even at the prehypertensive stage at 4 weeks of age, the inner medullary concentration of PLC-delta 1 was significantly lower in SHRs than WKY rats. These results suggest that PLC-delta 1 would play an important role in the development of hypertension.

Flat depressed early colon cancer--a case report

A flat depressed early colon cancer (FDEC) is characterized by non-polypoid growth pattern, no association of adenomatous tissues and a tendency of even small lesions toward submucosal invasion and lymph node metastasis. It supports de novo carcinogenesis of colorectal cancer, although most colorectal cancers arise in pre-existing adenoma (adenoma-carcinoma sequence). There have been few reports of small depressed cancers because of the difficulty in colonoscopic detection and the rapid development to ulcerating advanced cancers. We report a case of flat depressed early colon cancer confined to mucosa detected by indigo carmine contrast colonoscopy.

Silica-induced oxygen radical generation in alveolar macrophage

Silica is a well-known occupational fibrogenic agent and its primary target cell is alveolar macrophage. Particle-stimulated macrophages are believed to release various mediator which can regulate the inflammation as well as pulmonary fibrosis. Even though oxygen radicals play the major role among these mediators, the mechanisms concerning the stimulation of alveolar macrophages are not clear yet. The present study was carried out to investigate the signal transduction pathway on oxygen radical generation in silica-stimulated alveolar macrophages. Silica induced oxygen radical generation in a dose-response pattern. Extracellular calcium depletion, calcium channel blockers, and calcium release blocker decreased the effect of silica on oxygen radical generation. Silica increased intracellular calcium through the influx of calcium through the calcium channel and the calcium release from the intracellular calcium store. To know the role of protein kinase C (PKC), phospholipase C (PLC), and protein tyrosine kinase (PTK) in silica-induced oxygen radical generation, we pretreated alveolar macrophages with inhibitors of these enzymes. Inhibitors of PKC (sphingosine and staurosporine), PLC (neomycin and U-73122), and PTK (genistein and erbstatin) suppressed the silica-induced oxygen radical generation. Silica increased the PLC activity at the concentration of 5 mg/ml. The inhibitors of PTK and PLC suppressed the action of silica on the PLC activity. From these results, we suggest that silica induces oxygen radical generation through PTK, PLC, and PKC in alveolar macrophages.

Renal potassium wasting and hypocalciuria ameliorated with magnesium repletion in Gitelman's syndrome

A woman aged 45 years was presented with hypokalemic metabolic alkalosis and hypomagnesemia associated with renal potassium and magnesium wasting. Her 24-hour urinary calcium excretion was strikingly low despite normocalcemia and normal creatinine clearance, which is one of characteristic findings of Gitelman's syndrome (GS). She was evaluated for the responses following Mg supplementation for 10 days, which showed marked increments in serum potassium and magnesium as well as improvements of the degree of renal potassium wasting and hypocalciuria. This amelioration of abnormal biochemical pictures in this patient after Mg supplementation proposes that the hypokalemia with renal potassium wasting and hypocalciuria may be caused by abnormal Mg metabolism.

Gallbladder motility change in late pregnancy and after delivery

OBJECTIVES

The incidence of gallstone disease has increased recently in Korea and there seems to be an increased prevalence of gallstones when in association with pregnancy. Although the pathogenesis is incompletely defined, and altered motility of the gallbladder may contribute to the increased risk of gallstones during pregnancy.

METHODS

We measured gallbladder volume using real-time ultrasonography to find out the mechanism for the changes of gallbladder motility during late pregnancy. Eighteen pregnant women took the gallbladder ultrasonography during their last trimester of pregnancy and after delivery; gallbladder volume and ejection fraction were calculated in each patient.

RESULTS

Fasting gallbladder volumes increased significantly in the last trimester of pregnancy (25.28 +/- 14.26ml) compared with postpartum (17.44 +/- 5.82 ml) (p < 0.05). Gallbladder volumes measured after fatty meals showed more increment in pregnant women (10.13 +/- 7.19 ml) than in those after delivery (4.34 +/- 3.36 ml) (p < 0.005). A significantly reduced gallbladder ejection fraction was found in the pregnant group (60.56 +/- 18.80%) compared with those after delivery (77.48 +/- 13.37%) (p < 0.005).

CONCLUSION

Gallbladder motility in late pregnancy shows significant impairment compared with that in postpartum. Thus, we suggest that gallbladder hypomotility may occur during late pregnancy, and this impairment of gallbladder motility may play an important role in gallstone formation.

Pathological changes according to the severity of asthma

BACKGROUND

There have been many studies concerning pathological changes in bronchial mucosa from asthmatics; however, few studies has been carried out to evaluate pathological changes according to the severity of asthma.

OBJECTIVE

This study was designed to evaluate the cellular components in bronchoalveolar lavage fluid (BALF) and histological abnormalities in asthmatics according to the severity of asthma.

METHODS

Bronchoalveolar lavages, bronchoscopic biopsies and ultrastructural examinations were performed in 13 asthmatics and 11 (BAL) or four (biopsies) non-asthmatic controls. The proportions of epithelial cells and correlations with PC20Meth which reflects bronchial hyperresponsiveness. Light microscopic examination revealed loss of epithelium, inflammatory cell infiltrations and thickening of the basement membrane which also showed significant correlation with PC20Meth. Hypertrophy of airway smooth muscles and hyperplasia of mucous glands were prominent in asthmatics but there was no difference according to the severity of asthma. Ultrastructural examination revealed that basement membrane thickening on light microscopic examination is due to the increased subepithelial collagen deposition with normal thickness of basal lamina.

CONCLUSION

These data suggest that loss of epithelial cells, infiltration of inflammatory cells, especially eosinophils, and increased deposition of subepithelial collagen play major roles in determining the severity of asthma and non-specific bronchial hyperresponsiveness.

Properties of analogues of an intermediate in the process of mechanism-based inactivation of carboxypeptidase A

Carboxypeptidase A (CPA), and other zinc-dependent proteases, facilitate an alpha deprotonation of judiciously designed ketones and amides. This adventitious reaction has been used in the development of effective mechanism-based inactivators for this family of enzymes. N-Acryloyl-L-phenylalanine, an intermediate in the process of mechanism-based inactivation of CPA by N-(3-chloropropionyl)-L-phenylalanine, was shown to be an affinity inactivator, but also a very poor substrate for the enzyme. Similarly, O-(acryloyl)-L-3-phenyllactate was shown to be both an affinity inactivator and a poor substrate for CPA. However, consistent with the trend established with other ester and amide substrates for CPA, O-(acryloyl)-L-3-phenyllactate is a better substrate than N-acryloyl-L-phenylalanine. N-(Propiolyl)-L-phenylalanine served only as a poor substrate for the enzyme. To gain insight into enzyme inactivation and the unexpected poor turnover of these molecules, molecular modeling of these compounds with the crystal structure of CPA was carried out. These analyses suggested that the smaller size of these molecules permits a binding mode which is somewhat different in the active site than with typical larger substrates, such that the transition-state species for hydrolysis is not greatly stabilized by the enzyme. The slow turnover of these species, along with their specific binding interactions with the enzyme active site have implications for the inactivation chemistry of CPA and other zinc proteases by this family of mechanism-based inactivators.

Translocation of lipocortin (annexin) 1 to the membrane of U937 cells induced by phorbol ester, but not by dexamethasone

1. Induction of lipocortin 1 secretion by dexamethasone has been demonstrated, although the secretory mechanism is still unknown. We have studied the effects of 12-tetradecanoyl phorbol 13-acetate (TPA) and/or dexamethasone on the expression, translocation, and secretion of lipocortin 1 in U937 cells. 2. The expression of lipocortin 1 and its mRNA increased during TPA-induced differentiation of U937 cells to a maximum of 1.9 fold and 8.2 fold, respectively, after 48 h. Both the protein and the mRNA levels decreased after 48 h. 3. TPA caused the translocation of lipocortin 1 from the cytosol to the membrane of U937 cells in a time-dependent manner, as determined by Western blot analysis. The translocation was concurrent with the differentiation of the cells. After 48 h of TPA treatment, 82.6 +/- 6.5% of lipocortin 1 was present in the membrane fraction compared to 41.6 +/- 1.7% in untreated cells. 4. The amount of lipocortin 1 that was externally bound (associated) with the membrane increased to 3.2 fold as the cytosol to membrane translocation of lipocortin 1 increased. 5. Dexamethasone decreased the externally bound lipocortin 1, but had no effect on the cytosol to membrane translocation. 6. This offers a model system with which the function and the secretion mechanism of lipocortin 1 can be studied. Our data is consistent with the hypothesis that the secretory mechanism is through an unknown pathway, involving the translocation of lipocortin 1 from the cytosol to the internal membranes, and then, its secretion to the external membrane.

[Interleukin-8 gene expression in the human colon epithelial cell line, HT-29, exposed to Entamoeba histolytica]

The protozoan parasite, Entamoeba histolytica, is one of major causative agents of intestinal disease all over the world. In acute experimental infection, the early host response to E. histolytica is characterized by an infiltration of neutrophils. However, the chemotactic signal for this response is not well known. Based on the finding that human epithelial cells produce the potent neutrophil chemoattractant and activator, interleukin-8 (IL-8), IL-8 gene expression was examined thoroughly in human colon epithelial cells exposed to E. histolytica trophozoites. Cellular RNAs were extracted from HT-29 or Caco-2 human colon epithelial cells exposed to E. histolytica trophozoites for 30 minutes, 1 and 3 hours. IL-8 mRNA transcripts were measured by reverse transcriptional polymerase chain reaction (RT-PCR) using synthetic standard RNA. The number of IL-8 mRNA molecules increased from 30 minutes to 3 hours of exposure period, reaching 3.1 x 10(7) molecules/micrograms of total RNA. Expression pattern of IL-8 mRNA transcripts was parallel to the amounts of IL-8 protein measured by enzyme-linked immunosorbent assay (ELISA). Lysates of E. histolytica also induced expression of mRNA for IL-8 in colon epithelial cells. These results suggest that acute inflammatory reaction by E. histolytica may be initially triggered by proinflammatory cytokines such as IL-8 secreted from epithelial cells of the colon.

Evidence suggesting a role for phospholipase C isozyme, PLC-delta 1 in corticomedullary osmotic gradients in rat kidneys

We determined the distributional patterns of phospholipase C isozymes within the rat kidneys. PLC-beta1 was localized in the inner medulla at the highest degree followed by the inner stripe of the outer medulla, the cortex and the outer stripe of the outer medulla. PLC-gamma1 was distributed homogeneously along the corticomedullary axis. PLC-delta1 showed gradual increase from the cortex to the inner medulla. Tissue osmotic gradients were measured using 4 slices, resulting in gradual increase from the cortex to the inner medulla. The pattern of PLC-delta1 appeared very similar to the osmotic gradient in the kidney. The results suggest that the distinct patterns of the PLC isozymes may be associated with different signal transduction pathways along the corticomedullary axis and PLC-delta1 may play a role in the osmoregulation of the medullary region.

Epidermal surface antigen (MS17S1) is highly conserved between mouse and human

A mouse monoclonal antibody ECS-1 raised to human keratinocytes detects a 35-kDa epidermal surface antigen (ESA) and causes keratinocyte dissociation in vitro. ECS-1 stains skin of 16-day mouse embryo and 8- to 9-week human fetus. Mouse Esa cDNA encodes a 379-amino-acid protein that is 99.2% identical to the human, differing at only 3 amino acids. The gene (M17S1) was mapped to mouse chromosome 11, high-lighting the conserved linkage synteny existing between human chromosome 17 and mouse chromosome 11. Although the nude locus has been mapped to the same region of chromosome 11, no abnormalities in protein, mRNA, or cDNA or genomic sequences were detected in nude mice. However, both nude and control mice were found to have a second Esa mRNA transcript that conserves amino acid sequence and molecular weight. The mouse and human 5' and 3' untranslated sequences are conserved. Similar RNA folding patterns of the 5' untranslated region are predicted despite a 91-bp insertion in the mouse. These data suggest that both the function and the regulation of ESA protein are of importance and that Esa (M17S1) is not the nude locus gene.

Acute lung disease after exposure to fly ash

A 48-year-old man with no history of pulmonary disease developed acute lung disease after the intensive exposure of fly ash. He subsequently had progressive worsening of shortness of breath and hypoxemia to the point of requiring mechanical ventilation. Fly ash is a compound consisting of silicon dioxide and various other substances and is used in industrial settings to generate electricity. Exposure to fly ash may cause irritation to the mucous membrane of the respiratory tract and even pulmonary fibrosis in humans. To our knowledge, this is the first case report described in the medical literature of acute lung disease developing after fly ash exposure.

Effects of low density lipoprotein on type IV collagen production by cultured rat mesangial cells

Hyperlipidemia, especially hypercholesterolemia, may contribute to glomerulosclerosis as it does to atherosclerosis. Low density lipoprotein (LDL) stimulates the production of extracellular matrix by mesangial cells in culture as well as the proliferation of mesangial cells. This study was carried out to examine the effects of LDL on the type IV collagen (CIV) production by cultured rat mesangial cells (CRMC). Subconfluent CRMC monolayers which were grown in RPMI with 20% lipid-free fetal calf serum for 48 h were challenged with LDL (0, 50, 100, 150 and 200 micrograms/ml) for another 48 h. LDL was prepared from normal human plasma. Mesangial cell proliferation was examined by [3H]-thymidine uptake. Production of CIV was evaluated as the expression of CIV on the cell surface by flow-cytometric analysis. The collagen synthesis was measured by the [3H]-proline uptake. Total RNA was extracted from CRMC at 6 and 24 h of incubation with 150 micrograms/ml LDL, and Northern blotting and hybridization was performed with cDNAs for alpha 1-CIV, for 72-kD collagenase and for tissue inhibitor of metalloproteinase (TIMP)-2. The amount of total mRNA was corrected with beta-actin mRNA. Mesangial cell proliferation increased in all concentrations studied and had a peak value of 221% with 150 micrograms/ml of LDL. Expression of CIV increased by 30-60% in 100-200 micrograms/ml of LDL. Collagen synthesis also increased by 50-70% in 150-200 micrograms/ml of LDL. The mRNA ratio (procollagen alpha 1(IV)/beta-actin) increased to 133% at 24 h. The mRNA ratio (TIMP-2/beta-actin) increased to 137% at 24 h. mRNA ratios at 6 h showed no change.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular induction pathways for CD23 antigen and surface immunoglobulins in human tonsillar B cells: the roles of protein kinase C and tyrosine kinase-mediated signals

The expression of CD23 on human tonsillar B cells is increased following treatment with interleukin 4 (IL-4) or 12-O-tetradecanoylphorbol 13-acetate (TPA), while that of surface immunoglobulins (sIgs) is increased by IL-4 but decreased by TPA. This suggests that the signaling by these effectors may result from distinct second messenger-generating systems. In this study, we attempted to elucidate the signal transduction pathways responsible for the expression of CD23 and sIgs by using different protein kinase C (PKC) and tyrosine kinase (TK) inhibitors. Our results showed that B cells expressed varying amounts of sIgs depending on different activators and inhibitors. Sphingosine, a PKC inhibitor, almost completely reversed the TPA-induced decrease in sIgM and sIgD expression. Other PKC inhibitors, e.g., H7 and staurosporine, had similar but less profound effects. In comparison, the up-regulation of CD23 by IL-4 and TPA was only partially blocked by these PKC inhibitors. TK inhibitors, such as herbimycin A and genistein, decreased both the IL-4- and TPA-induced CD23 expression by 50-80%, but had modest effects on sIgs expression. These findings indicate that CD23 and sIgs expression is regulated by independent pathways; PKC is important for the regulation of sIgs expression while the signals through TK pathways might play the major role in CD23 expression.

Extraction and simultaneous elution and derivatization of 11-nor-9-carboxy-delta 9-tetrahydrocannabinol using Toxi-Lab SPEC prior to GC/MS analysis of urine

A new sample preparation procedure is described for the extraction and simultaneous elution and derivation of urine for analysis of 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (THC-COOH) by gas chromatography/ion trap mass spectrometry (GC/MS). Urine samples are extracted for THC-COOH and d6-THC-COOH internal standard onto a hydrophobic membrane. Extracts are simultaneously eluted and derivatized with MSTFA while on the membrane to produce the corresponding trimethylsilane derivative. Using results of blank urine, the limits of detection and quantitation were 1.1 and 2.5 ng/mL, respectively. The linearity of the assay was 250 ng/mL. The within-run and day-to-day precision ranged 3-5%. Compared with a solid-phase column extraction procedure, the overall time for sample preparation was decreased from 3 h down to 1. The SPEC extraction procedure with trimethyl derivatization produces a cleaner total ion chromatogram than the solid-phase column extraction system (minicolumn) and does not require the use of any organic solvents.