Reverse Transcriptase-polymerase Chain Reaction Technique Research Articles

An Outbreak of Norovirus Gastroenteritis on an Israeli Military Base

Noroviruses (NVs) are a predominant cause of viral gastroenteritis outbreaks, but they are difficult to identify because they cannot be cultivated in cell culture. Therefore, reverse-transcriptase polymerase chain reaction (RT-PCR) assays are widely used in the testing of clinical stool specimens for NV. However, testing of perianal swabs in the context of an outbreak is considered to be an insensitive method for identification of NV using the RT-PCR technique. An outbreak of acute gastroenteritis involving 159 soldiers on a training base of the Israel Defense Force in December 1999 allowed us to evaluate this identification method. An epidemiologic investigation, a sanitation survey and a case-control study of exposure to different food items served up to 48 h preceding the outbreak were conducted. Stool samples in the form of post-defecation perianal swabs were collected from 24 ill personnel and three non-ill food handlers. Swabs were tested for the presence of NV by RT-PCR assay. Epidemiologic data were consistent with a pointsource food-borne outbreak which was associated with consumption of fresh vegetable salad in the base mess hall (OR = 4.38, 95% CI 1.51-13.35). Both epidemiologic and clinical features were suggestive of gastroenteritis caused by NV, and upon laboratory analysis perianal swabs from four of 24 cases were positive for NV. The combination of practical specimen collection with perianal post-defecation swabs, and the utilization of a molecular epidemiology approach, can simplify the rapid identification of outbreaks caused by NVs.

Detection of Cytokeratin-19 in Peripheral Blood of Breast Cancer Patients: Results from a Systematic Review/Meta-Analysis.

Abstract Background: The identification of occult micrometastatic disease is potentially important in management of breast cancer (BC) patients. Therefore, detection of cytokeratin 19 (CK-19) and others molecular markers using reverse transcriptase polymerase chain reaction (RT-PCR)-based techniques to detect micrometastases could have significant implications in prevention, early detection and treatment of breast cancer. Objective: To assess the diagnostic specificity and sensitivity of detection of CK-19 in the peripheral blood (PB) of BC patients as well as to assess its relation to prognostic factors and implication on survival. Methods: We conducted a systematic review/meta-analysis of all studies that analyzed CK-19 in the PB of BC patients. We searched MEDLINE, LILACS and Cochrane Database of Systematic Reviews (last search June 2004). Studies that had at least 10 BC patients and controls and evaluated the presence of CK-19 in PB using RT-PCR were included in this review. Diagnostic sensitivity was defined as the percentage of detection of CK-19 in patients with histological proven diagnosis of breast cancer. The specificity was defined as the percentage of negative tests for CK-19 in the control group (healthy individuals or non breast cancer patients). Results: Out of 1842 relevant studies that were identified, 26 met our inclusion criteria, enrolling 2398 patients (1176 treatment and 1222 controls). Results showed that PCR had an overall diagnostic sensitivity of 0.39 (95% CI: 0.36–0.42) and diagnostic specificity of 0.83 (95% CI: 0.76–0.87) regardless of the breast cancer stage. Six studies researched the association between CK-19 and well established prognostic factors (i.e. positive axillary lymph nodes, hormonal receptors, tumor size); however data were not available for quantitative synthesis. Survival was poorly reported making impossible to generate any conclusion about the implication of detection of CK-19 on prognosis. When studies were critically appraised, we also identified many methodological weaknesses in the design, conduct and the analysis of these studies (e.g. use of multiple control arms, use of non-consecutive patients, different timing of sample collection, inclusion of all stages of breast cancer and differential work-up in the study & control groups) hence resulting in biased findings due to selection, verification, detection and spectrum bias. Conclusion: The existing body of evidence regarding the assessment and prognostic value of CK-19 using RT-PCR techniques is poor and needs ample improvement before the initiation of its clinical application.

Wertigkeit des Nachweises von in peripherer Blutbahn zirkulierenden Zellen des hepatozellulären Karzinoms mittels RT-PCR

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignancies. Tumor recurrence is, however, frequent and may be due to undetectable tumor cells. Reverse transcriptase polymerase chain reaction (RT-PCR) has been used to detect those tumor cells in peripheral blood but has several disadvantages. METHODS: Peripheral blood from 47 patients (group A, 19 patients with newly diagnosed HCC; group B, 20 control patients with non-HCC liver lesions; Group C, 8 HCC aftercare patients) was tested for the presence of circulating HCC cells by demonstration of alpha-fetoprotein mRNA by the RT-PCR technique. RESULTS: Six patients with newly diagnosed HCC tested positive for circulating HCC cells. No patient in the control group or the aftercare group was positive for alpha-fetoprotein mRNA. CONCLUSIONS: The specificity (100%) of alpha-fetoprotein mRNA as a marker for HCC cells in circulating blood was satisfactory but the sensitivity (31.6%) was disappointing. Our experience is that this method of detecting circulating HCC cells did not provide any clinically relevant information and that we should focus our interest on methods like the isolation by size of epithelial tumor cells for the detection of circulating tumor cells in the future.

Identification of the M‐CSF Receptor in Endometriosis by Immunohistochemistry and RT‐PCR

The aim of this paper is to provide further evidence that the dystopic proliferation of endometriotic epithelia is caused by the stimulation of peritoneal macrophages. It is essential to show that endometriotic epithelial cells express the macrophage colony-stimulating factor receptor (M-CSFR) which binds the M-CSF produced by the peritoneal macrophages. For the detection of M-CSFR, samples of ectopic endometrium (n = 79) and eutopic endometrium (n = 18) were compared. The specimens were gained at operative laparoscopy in the proliferative phase of the cycle. Cryostat sections were used for immunohistochemical detection. For in vitro reverse transcriptase polymerase chain reaction (RT-PCR) tests, the tissue was immediately shock frozen on paraffin sections. For the in situ RT-PCR technique the specimens were placed in a para-formaldehyde solution, embedded in paraffin and later processed. The Gene Amp 1000 in situ PCR system (Perkin Elmer) was used as the thermal cycler. M-CSF and the M-CSF receptor are present in eutopic and ectopic endometrium. Qualitatively, with both PCR techniques we found the M-CSF receptor to be present in all samples examined. Using the histochemical detection technique, the M-CSF receptor was found in nearly 70% of endometriosis patients compared with a statistically significant lower percentage in normal endometrium. The in situ RT-PCR technique and immunohistochemistry elaborated the need to trace the cellular sources of the M-CSF receptor. The identification of the M-CSF receptor in endometriotic tissue and in endometrium is apt to open a new experimental field in endometriosis research.

Gastric cancer cell detection in peritoneal lavage: RT-PCR for carcinoembryonic antigen transcripts versus the combined cytology with peritoneal carcinoembryonic antigen levels

Free cancer cells exfoliated from the serosal surfaces of primary cancers are considered to be responsible for peritoneal dissemination, which are both the most frequent pattern of treatment failure and the most important cause of death in gastric cancer patients. Detection of free cancer cells in the peritoneal cavity at the time of surgery, therefore, is thought to be of great value in predicting peritoneal recurrence and accordingly the prognosis of gastric cancer patients. This study was designed to determine whether free cancer cells in peritoneal lavage fluid from gastric cancer patients could be identified by a reverse-transcriptase polymerase chain reaction (RT-PCR) method specific to carcinoembryonic antigen (CEA) mRNA. Simultaneously, the results from conventional cytological examination were evaluated and the levels of CEA in peritoneal lavage were determined. Of the 40 gastric cancer patients enrolling in this investigation, 11 (27.5%) were positive for CEA mRNA in their peritoneal lavage, whereas only 6 (15%) and 8 (20%) were shown to be positive by cytological examination and peritoneal CEA (pCEA) assay, respectively. Furthermore, RT-PCR positive for CEA mRNA was correlated with the depth of tumor invasion ( P<0.001), lymph node metastases ( P=0.004), the TNM stage ( P<0.001) and peritoneal recurrence ( P<0.001). The technique of RT-PCR was more sensitive than conventional cytological examination and pCEA levels in the detection of peritoneal free cancer cells as well as in the prediction of peritoneal recurrence. In addition, CEA RT-PCR had a high concordance rate (82.5%) with the combination of cytology with pCEA levels. These observations suggest that it is feasible to identify free cancer cells in peritoneal lavage by using a CEA mRNA-specific RT-PCR method, and this assay can be a promising diagnostic modality for evaluating the risk of peritoneal dissemination in gastric cancer patients following operations.

Detection of circulating breast cancer cells in peripheral blood by a two-marker reverse transcriptase-polymerase chain reaction assay.

The aim of this study was to use a two-marker assay for the detection of breast cancer cells circulating in patients' blood. We have applied a PCR-based methodology to follow up the possibility of the development of metastatic disease in stage I and II patients who had undergone curative surgery. Since the number of circulating cancer cells in peripheral blood is very low, the technique for their detection needs to be not only highly sensitive, but also very specific. The reverse transcriptase-polymerase chain reaction (RT-PCR) technique may improve the sensitivity of breast cancer cell detection up to only a few cells per one million. The principle of the RT-PCR assay is to amplify a messenger RNA characteristic for breast epithelial cells in a blood sample. Since we do not expect such cells to be circulating in peripheral blood of healthy subjects, detection of the characteristic mRNA should indicate the presence of circulating breast cancer cells. We analyzed the usefulness of three mRNA markers: cytokeratin 19 (CK19), mammaglobin (hMAM) and beta subunit of human chorionic gonadotropin (beta-hCG) for this test. Blood samples (112) were obtained from 55 patients, in stages I and II, with or without metastasis to regional lymph nodes (N0 or N1). We found that a two-marker assay increases the sensitivity of detection of breast cancer cells in comparison with a single-marker one. Combination of two tumor-specific mRNA markers, hMAM/CK19 or beta-hCG/CK19, allowed the detection of circulating breast cancer cells in 65% of N1 patients and 38% of N0 patients. By comparison, the combination hMAM/beta-hCG allowed the detection of circulating breast cancer cells in the blood of 68% of N1 patients and 46% of N0 patients. Addition of the third marker did not significantly increase the detection sensitivity.

Detection of circulating breast cancer cells in peripheral blood by a two-marker reverse transcriptase-polymerase chain reaction assay.

The aim of this study was to use a two-marker assay for the detection of breast cancer cells circulating in patients' blood. We have applied a PCR-based methodology to follow up the possibility of the development of metastatic disease in stage I and II patients who had undergone curative surgery. Since the number of circulating cancer cells in peripheral blood is very low, the technique for their detection needs to be not only highly sensitive, but also very specific. The reverse transcriptase-polymerase chain reaction (RT-PCR) technique may improve the sensitivity of breast cancer cell detection up to only a few cells per one million. The principle of the RT-PCR assay is to amplify a messenger RNA characteristic for breast epithelial cells in a blood sample. Since we do not expect such cells to be circulating in peripheral blood of healthy subjects, detection of the characteristic mRNA should indicate the presence of circulating breast cancer cells. We analyzed the usefulness of three mRNA markers: cytokeratin 19 (CK19), mammaglobin (hMAM) and beta subunit of human chorionic gonadotropin (beta-hCG) for this test. Blood samples (112) were obtained from 55 patients, in stages I and II, with or without metastasis to regional lymph nodes (N0 or N1). We found that a two-marker assay increases the sensitivity of detection of breast cancer cells in comparison with a single-marker one. Combination of two tumor-specific mRNA markers, hMAM/CK19 or beta-hCG/CK19, allowed the detection of circulating breast cancer cells in 65% of N1 patients and 38% of N0 patients. By comparison, the combination hMAM/beta-hCG allowed the detection of circulating breast cancer cells in the blood of 68% of N1 patients and 46% of N0 patients. Addition of the third marker did not significantly increase the detection sensitivity.

Fluorescence In Situ Hybridization Identifies Cryptic t(16;16)(p13;q22) Masked By del(16)(q22) in a Case of AML-M4 Eo

We report a patient presenting with acute myeloid leukemia (AML)-M4 Eo, in whom conventional cytogenetic analysis revealed a 46, XY, del(16)(q22) karyotype. Molecular analysis of the bone marrow cells using reverse transcriptase polymerase chain reaction (RT-PCR) identified a CBFbeta-MYH11, "type A" fusion transcript. However, despite a thorough reevaluation, a balanced chromosome 16 abnormality could not be definitively identified by cytogenetics. Since there exists a small possibility of obtaining a false-positive PCR result, fluorescence in situ hybridization (FISH) analysis using dual-color, break-apart probes for CBFbeta was performed to elucidate the mechanism of fusion gene formation and thus confirm the RT-PCR results. FISH analysis clearly revealed a cryptic t(16;16), which was probably masked by the del(16)(q22). FISH is the preferred diagnostic procedure to elucidate the CBFbeta-MYH11 fusion in this situation, and resolves the possibility of both false-positive and false-negative results with RT-PCR technique. Due to the improved prognosis of AML associated with the CBFbeta-MYH11 fusion compared to AML generally, we recommend the use of FISH for detection of inv(16)/t(16;16)/CBFbeta-MYH11 in patients with failed, complex, or apparently normal cytogenetics, and in whom the cell morphology indicates the strong possibility of this gene fusion.

Molecular identification, localization and function of platelet-type 12-lipoxygenase in human melanoma progression, under experimental and clinical conditions

As previous studies suggested the expression of a 12-LOX enzyme in murine and human melanoma cell lines, the primary aim of this project was to genetically identify the 12-LOX enzyme (platelet-, leukocyte- or epithelial form). By using reverse transcriptase-polymerase chain reaction, sequencing and various immunological techniques we have demonstrated conclusively the expression of the platelet-type 12-LOX in human melanoma cells of different origin, in their transplanted xenografts and in fresh human skin tumors. Furthermore, we found that p12-LOX is able to provide a survival signal for melanoma cells since inhibition of the enzyme by general LOX or selective 12-LOX inhibitors induced apoptosis in vitro. p12-LOX of human melanoma has been shown to be involved in the control of the metastatic phenotype, since we have detected the upregulation of the 12-LOX protein expression in spontaneously metastasizing xenografts and in thick human skin tumors (> 3.0 mm) characterized by high risk for the development of metastasis. Co-expression of two megakaryocytic genes, p12-LOX and alphaIIb integrin chains, was found to be a frequent phenomenon in human melanoma (approximately 70%) suggesting a common regulatory defect in this tumor.

Association of a high activity of matrix metalloproteinase-9 to low levels of tissue inhibitors of metalloproteinase-1 and -3 in human hepatitis B-viral hepatoma cells

Matrix metalloproteinases (MMPs) play a major role in the turnover of extracellular matrix (ECM) during cancer invasion and metastasis, and tissue inhibitors of metalloproteinases (TIMPs) control MMPs, thus maintaining a balanced ECM catabolism under physiological conditions. The aim of this study was to assess the behavior of some MMPs (FASEB J., 7, 1993, 1434; Cancer Metastasis Rev., 9(4) 1990, 289) and TIMPs (Biochem. Biophys. Res. Commun., 301, 2003, 1069; FASEB J., 7, 1993, 1434; Nature, 370, 1994, 61). Competitive RT-PCR, gelatin-substrate zymography, and ELISA techniques were used for quantification. The hepatitis B virus (HBV)-DNA-containing hepatocellular carcinoma cell lines, Hep3B, HepG2-HBV and HFF-T2 contain highly activated matrix metallproteinase-9 (MMP-9), which is rarely found in normal liver cell lines such as the Chang lines. MMP-9 activities of HFH-T2, HepG2-HBV and Hep3B were significantly higher than that of non-HBV-hepatocellular carcinoma SK-Hep1 and HepG2 (HCC origin, HBV not detected), as assayed by gelatin zymography. Low levels of TIMP-1 and TIMP-3 were observed in HFH-T2, HepG2-HBV and Hep3B, while the TIMP-2 level was high, as evidenced by reverse zymography. In contrast, 3 TIMP-1, -2 and -3 were largely detected in Chang, HepG2 and SK-Hep1 cells. To investigate the nature of the quantitative regulation of MMPs and TIMPs for these cell lines at the transcriptional levels, a reverse transcriptase-polymerase chain reaction (RT-PCR) was carried out. Not only MMP-9 mRNAs of HFH-T2, HepG2-HBV and Hep3B but also MMP-9 mRNA of SK-Hep1 and HepG2 were highly expressed with no major differences among these four cell lines. However, TIMP-1 and TIMP-3 mRNAs of HFH-T2, HepG2-HBV and Hep3B were markedly reduced, while those of SK-Hep1, HepG2 and Chang cells were maintained at high levels. Finally, an invasion assay using matrigel indicated in an increase in invasiveness in HFH-T2, HepG2-HBV and Hep3B cells, but a decrease in invasiveness of Chang, HepG2 and SK-Hep1 cells. These results indicate that the overexpression of MMP-9 mRNAs and the suppression of TIMP-1 and TIMP-3 in HFH-T2, HepG2-HBV and Hep3B were the result of HBV transfection. Based on these results, it is concluded that HBV affects the malignance of hepatocellular cancer by elevating MMP-9 activity, and suppressing TIMP-1 and TIMP-3.

Cyclooxygenases mRNA and protein expression in striata in the experimental mouse model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine administration to mouse

Cyclooxygenases (COX) are associated with complex alteration in many pathologies of the central nervous system (CNS). Increased expression of COX-2 has been shown in injured or degenerated neurons, thus suggesting that COX-2 may contribute to neuronal damage. In this study, we present the expression of COX-1 and COX-2 mRNA and protein in striatum following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration to mice. MPTP causes an acute damage of dopaminergic neurons especially in the nigrostriatal dopaminergic system, thus diminishing dopamine (DA) content in striatum and decreasing the number of dopaminergic cells in the pars compacta of the substantia nigra (SN). C57Bl mice have received 60 mg/kg of MPTP introperitoneally. A group of mice received also rofecoxib 10 mg/kg from the 1st day following MPTP administration. Dopamine content in striatum (high-performance liquid chromatography—HPLC), mRNA expression of COX-1 and -2 (reverse transcriptase-polymerase chain reaction technique—RT-PCR), COX-1 and -2 protein content (immunoblotting) have been measured on day 1st, 3rd, 7th, 14th and 21st after the injury. We have found that COX-1 mRNA expression is not changed following MPTP administration, but COX-2 gene and protein expression in striatum increases from the 3rd to the 7th and 14th days, and diminishes on the 21st day. Production of prostaglandins is augmented only briefly after MPTP treatment and did not correlate with increased COX-2 mRNA and COX-2 protein production. Thus, the increase of COX-2 expression does not follow the acute stage of cell death but rather the recovery period after the injury. We also demonstrate that COX-2 activity inhibition by rofecoxib (10 mg/kg), which has been started 1 day after the injury, has not neuroprotective effect. Our study suggests that COX-2 does not contribute to neurons death following MPTP administration and that the inhibition of COX-2 activity is not beneficial to neurons injured by MPTP. However, COX-2 mRNA and protein expressions increase after MPTP injury; the role of these findings remains obscure.

Clinical relevance of survivin as a biomarker in neoplasms, especially in adult T-cell leukemias and acute leukemias.

Survivin has been identified as one of the top 4 transcripts among 3.5 million human transcriptomes uniformly up-regulated in cancer tissues but not in normal tissues. Therefore, we quantitatively determined the messenger RNA (mRNA) expression profile for survivin by a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) technique in 113 patients with leukemias, such as adult T-cell leukemia (ATL), acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia in crisis, and chronic lymphocytic leukemia (CLL), and in 25 cell lines, including 7 ATL cell lines and 15 solid-tumor cell lines. Furthermore, we examined whether the plasma level of survivin protein as measured by enzyme-linked immunosorbent assay (ELISA) substituted for mRNA expression by PCR quantification. Gene expression was quantitatively confirmed to be up-regulated in approximately 90% of ATL and acute leukemia cases and in all of the cell lines tested, whereas it was down-regulated in almost all cases of CLL. Furthermore, with respect to the interpretation of the gene expression findings, attention was paid to standardization with a housekeeping gene, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), in the real-time PCR quantification, because the variability in GAPDH expression among the different cell types was significant. GAPDH expression was relatively low in ATL cells and high in ALL and AML cells. The rates of increase in the levels of survivin protein in the plasma of ATL patients and in the supernatants from in vitro cultures of solid-tumor cell lines were low compared with rates of increase of the mRNA and protein level in the cells, suggesting that the protein levels in plasma do not always reflect survivin expression in tumor cells. Our findings indicate the potential clinical relevance of survivin quantified by real-time PCR but not for the protein level in plasma as determined by ELISA, especially in cases of ATL and acute leukemias.

The alpha7 nicotinic acetylcholine receptor subunit exists in two isoforms that contribute to functional ligand-gated ion channels.

Fast synaptic transmission in mammalian autonomic ganglia is mediated primarily by nicotinic receptors, and one of the most abundant nicotinic acetylcholine receptor subtypes in these neurons contains the alpha7 subunit (alpha7-nAChRs). Unlike alpha7-nAChRs expressed in other cells, the predominant alpha7-nAChR subtype found in rat intracardiac and superior cervical ganglion neurons exhibits a slow rate of desensitization and is reversibly blocked by alpha-bungarotoxin (alphaBgt). We report here the identification of an alpha7 subunit sequence variant in rat autonomic neurons that incorporates a novel 87-base pair cassette exon in the N terminus of the receptor and preserves the reading frame of the transcript. This alpha7 isoform was detected using reverse transcriptase-polymerase chain reaction techniques in neonatal rat brain and intracardiac and superior cervical ganglion neurons. Immunoblot experiments using a polyclonal antibody directed against the deduced amino acid sequence of the alpha7-2 insert showed a pattern of expression consistent with alpha7-2 subunit mRNA distribution. Moreover, the alpha7-2 subunit could be immunodepleted from protein extracts by solid-phase immunoprecipitation techniques using the anti-alpha7 monoclonal antibody 319. The alpha7-2 subunit was shown to form functional homomeric ion channels that were activated by acetylcholine and blocked by alpha-bungarotoxin when expressed in Xenopus laevis oocytes. This alpha7 isoform exhibited a slow rate of desensitization, and inhibition of these channels by alphaBgt reversed rapidly after washout. Taken together, these data indicate that the alpha7-2 subunit is capable of forming functional alphaBgt-sensitive acetylcholine receptors that resemble the alpha7-nAChRs previously identified in rat autonomic neurons. Furthermore, the distribution of the alpha7-2 isoform is not limited to peripheral neurons.

Telomerase activity and expression of telomerase genes in squamous dysplasia and squamous cell carcinoma of the esophagus.

Telomerase maintains telomere length and is considered to be necessary for the indefinite proliferation of human cells. Activation of telomerase plays a key role in the malignant transformation process. The aim of this study was to study the regulation of telomerase, and to explore the possibility of telomerase as a biomarker in squamous carcinogenesis of the esophagus. Twenty-nine esophageal squamous cell carcinomas (ESCC) and its corresponding adjacent normal tissues, and 47 epithelial squamous dysplasia tissues were analyzed by the reverse transcriptase-polymerase chain reaction (RT-PCR) technique for the mRNA expression of three major telomerase subunits: human telomerase RNA (hTR), telomerase protein component 1 (TP1), and human telomerase reverse transcriptase (hTERT) and by telomeric repeat amplification protocol assay (TRAP) for telomerase activity. For the expression of hTR and TP1 mRNA, there were no significant differences among ESCC, dysplasia and normal tissues (P > 0.05). In contrast, hTERT mRNA expression was detected in 28 of 29 ESCC (96.6%), in 23 of 47 dysplasia (48.9%), and only in two of 29 normal tissues (7.5%). Telomerase activity was positive in 25 of 29 ESCC (86.2%), in 21 of 47 (44.7%) epithelial dysplasia tissues, and in none of normal tissue. All together, 95 of 105 cases (90.48%) were concordant for both results, i.e., telomerase activity positive and hTERT positive or telomerase activity negative and hTERT negative tissues, and telomerase activity correlated with hTERT mRNA expression (P < 0.001). Higher telomerase activity and hTERT mRNA expression were shown during an early stage in the esophageal carcinogenesis. Activation of telomerase activity was strongly correlated with hTERT mRNA expression, suggesting hTERT is a major regulator of telomerase activity, and telomerase activation may play a critical role in esophageal carcinogenesis. Therefore, telomerase, especially hTERT can be used as a potential molecular biomarker of ESCC.

Timing of human insulin-like growth factor-1 gene transfer in reinnervating laryngeal muscle.

The authors have designed a rat laryngeal paralysis model to study gene transfer strategies using a muscle-specific expression system to enhance local delivery of human insulin-like growth factor-1 (hIGF-1). In preliminary studies, a nonviral vector containing the alpha-actin promoter and human hIGF-1 sequence produced both neurotrophic and myotrophic effects 1 month after single injection of plasmid formulation into paralyzed rat thyroarytenoid muscle in vivo. Based on these findings, it is hypothesized that the effects of hIGF-1 will enhance the results of laryngeal muscle innervation procedures. The timing of gene delivery relative to nerve repair is likely to be important, to optimize the results. Prospective analysis. The effects of nonviral gene transfer for the delivery of hIGF-1 were evaluated in rats treated immediately following recurrent laryngeal nerve transection and repair and in rats receiving a delayed treatment schedule, 30 days after nerve transection and repair. Gene transfer efficiency was determined using polymerase chain reaction and reverse transcriptase-polymerase chain reaction techniques. Muscle fiber diameter, motor endplate length, and percentage of motor endplates with nerve contact were examined to assess hIGF-1 trophic effects. Compared with reinnervated untreated control samples, both early and delayed hIGF-1 transfer resulted in significant increase in muscle fiber diameter. Motor endplate length was significantly decreased and nerve/motor endplate contact was significantly increased following delayed gene transfer, but not after early treatment. We infer from results of the study that delayed hIGF-1 gene transfer delivered by a single intramuscular injection will enhance the process of muscle reinnervation. The clinical relevance of these findings supports the future application of gene therapy using nonviral vectors for management of laryngeal paralysis and other peripheral nerve injuries.

Neuronal expression of CD22: novel mechanism for inhibiting microglial proinflammatory cytokine production.

Although considered an immunologically privileged site, the central nervous system (CNS) can display significant inflammatory responses, which may play a pathogenic role in a number of neurological diseases. Microglia appear to be particularly important for initiating and sustaining CNS inflammation. These cells exist in a quiescent form in the normal CNS, but acquire macrophage-like properties (including active phagocytosis, upregulation of proteins necessary for antigen presentation, and production of proinflammatory cytokines) after stimulation with inflammatory substances such as lipopolysaccharide (LPS). Recent studies have focused on elucidating the role of neurons in the regulation of microglial inflammatory responses. In the present study, we demonstrate, using neuron-microglial cocultures, that neurons are capable of inhibiting LPS-induced tumor necrosis factor-alpha (TNF-alpha) production by microglia. This inhibition appears to be dependent on secretion of substances at axon terminals, as treatment with the presynaptic calcium channel blocker omega-conotoxin abolishes this inhibitory effect. Moreover, we show that conditioned medium from neuronal cultures similarly inhibits microglial TNF-alpha production, which provides additional evidence that neurons secrete inhibitory substances. We previously demonstrated that the transmembrane protein-tyrosine phosphatase CD45 plays an important role in negatively regulating microglial activation. The recent characterization of CD22 as an endogenous ligand of this receptor led us to investigate whether neurons express this protein. Indeed, we were able to demonstrate CD22 mRNA and protein expression in cultured neurons and mouse brain, using reverse transcriptase-polymerase chain reaction and antibody-based techniques. Furthermore, we show that neurons secrete CD22, which functions as an inhibitor of microglial proinflammatory cytokine production.

Virus respiratoire syncytial et virus para-influenza : diagnostic virologique

The diagnosis of infection due to the respiratory syncytial virus (RSV) and parainfluenza virus (PIV) rests chiefly on detection of the virus or its antigens in a nasal specimen. The diagnostic yield depends on the number of respiratory cells collected in the specimen. RSV infection can be diagnosed rapidly using immunofluorescent assays and immunoenzymetric assays. Immunofluorescent assays are more difficult technically than immunoenzymetric assays but provide an assessment of the quality of the specimen. Virus isolation in cell cultures and detection of the viral RNA by reverse transcriptase-polymerase chain reaction techniques are possible for both the RSV and the PIV; however, these sophisticated, time-consuming, and costly tests now have a limited role as diagnostic tools.

The prolactin-releasing peptide receptor (GPR10) regulates body weight homeostasis in mice.

To identify new drug targets for the treatment of obesity, we employed a degenerate reverse transcriptasepolymerase chain reaction technique to isolate novel members of the G-protein coupled receptor superfamily from mouse hypothalamus. One of our clones was found to encode a protein with 90% amino acid identity to human GPR10, which was previously identified as the receptor for prolactin-releasing peptide (PrRP) and has been implicated in lactation, the regulation of food intake and other physiological functions. To investigate the role of GPR10 in food intake and body weight homeostasis, we generated mice carrying a targeted deletion of the GPR10 gene. First, using these knockout animals, we confirmed that GPR10 is the principle receptor for PrRP in the mouse hypothalamus because deletion of GPR10 completely abolished PrRP binding to isolated hypothalamic cell membranes. Second, we investigated the effect of normal and high-fat diets on energy intake, body weight, and glucose homeostasis in wild-type and GPR10 knockout mice. After fasting and refeeding, food intake in knockout animals was unchanged relative to control littermates. However, beginning at 16 wk of age on a normal diet, knockout mice became hyperphagic, obese, and showed significant increases in body fat and the levels of leptin and insulin, as well as decreased glucose tolerance. This metabolic profile was similar to the effect of a high-fat diet on wild-type animals. Our findings provide direct evidence that GPR10 is the receptor for PrRP and that it is involved in the regulation of energy balance in mice. GPR10 knockout mice will also prove useful for investigating other proposed activities for PrRP.

Skeletal muscle expression of creatine kinase-B in end-stage renal disease

The tissue specificity of creatine kinase (CK-MB) has been shown not to be absolute for the myocardium. Unexplained increases of plasma creatine kinase (CK-MB) occur in patients with skeletal muscle disease, confounding the diagnosis of myocardial injury. The purpose of this study was to examine the expression of CK-B as well as of the nuclear regulatory factor MyoD by Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) techniques in skeletal muscle biopsies obtained from end-stage renal disease (ESRD) patients. Quantitation of CKMB mass demonstrated a 35-fold greater concentration in skeletal muscle from ESRD patients (n=45) vs normal skeletal muscles (n=10), (p<0.01). In 22 of 45 ESRD skeletal muscles, CK-B expression was detected by Western blot analysis, molecular weight 46 kDa. In the seven CK-B Western blot positive tissues studied, one demonstrated a RT-PCR amplification product at 111 bp. In contrast, no CK-B expression was detected by either Western blot or RT-PCR in normal skeletal muscles. MyoD expression (98 bp) was found in all ESRD and normal skeletal muscles. The intensity of the MyoD expression was greatest in tissues that demonstrated a higher CKMB mass concentration. Our findings demonstrate an increase in CK-B protein expression in human skeletal muscle obtained from patients with ESRD, that may in part be controlled by an increase in expression of mRNA for CK-B. The resulting increase in CKMB mass in skeletal muscle from ESRD patients may also be regulated by alterations in expression of the nuclear regulatory protein MyD.

Measurement of Gene Expression in Archival Paraffin-Embedded Tissues: Development and Performance of a 92-Gene Reverse Transcriptase-Polymerase Chain Reaction Assay

Throughout the last decade many laboratories have shown that mRNA levels in formalin-fixed and paraffin-embedded (FPE) tissue specimens can be quantified by reverse transcriptase-polymerase chain reaction (RT-PCR) techniques despite the extensive RNA fragmentation that occurs in tissues so preserved. We have developed RT-PCR methods that are sensitive, precise, and that have multianalyte capability for potential wide use in clinical research and diagnostic assays. Here it is shown that the extent of fragmentation of extracted FPE tissue RNA significantly increases with archive storage time. Probe and primer sets for RT-PCR assays based on amplicons that are both short and homogeneous in length enable effective reference gene-based data normalization for cross comparison of specimens that differ substantially in age. A 48-gene assay used to compare gene expression profiles from the same breast cancer tissue that had been either frozen or FPE showed very similar profiles after reference gene-based normalization. A 92-gene assay, using RNA extracted from three 10- micro m FPE sections of archival breast cancer specimens (dating from 1985 to 2001) yielded analyzable data for these genes in all 62 tested specimens. The results were substantially concordant when estrogen receptor, progesterone receptor, and HER2 receptor status determined by RT-PCR was compared with immunohistochemistry assays for these receptors. Furthermore, the results highlight the advantages of RT-PCR over immunohistochemistry with respect to quantitation and dynamic range. These findings support the development of RT-PCR analysis of FPE tissue RNA as a platform for multianalyte clinical diagnostic tests.