Immunorecognition of Streptococcus mutans secreted proteins protects against caries by limiting tooth adhesion

INTRODUCTION

Childhood caries, a prevalent chronic disease, affects 60-90 % of children in industrialized regions, leading to lesions in both primary and permanent teeth. This condition precipitates hospital admissions, emergency room visits, elevated treatment costs, and missed school days, thereby impeding the child's academic engagement and increasing the likelihood of caries into adulthood. Despite multiple identified risk factors, significant interpersonal variability remains unexplained. The immune system generates a unique antibody repertoire, essential for maintaining a balanced and healthy oral microbiome. Streptococcus mutans is a primary contributor to the development of caries.

METHODS

Employing mass spectrometry, we investigated the S. mutans proteins targeted by antibodies in children both with and without caries, delineating a fundamental suite of proteins discernible by the immune systems of a majority of individuals. Notably, this suite was enriched with proteins pivotal for bacterial adhesion. To ascertain the physiological implications of these discoveries, we evaluated the efficacy of saliva in thwarting S. mutans adherence to dental surfaces.

RESULTS

Antibodies in most children recognized a core set of ten S. mutans proteins, with additional proteins identified in some individuals. There was no significant difference in the proteins identified by children with or without caries, but there was variation in antibody binding intensity to some proteins. Functionally, saliva from caries-free individuals, but not children with caries, was found to hinder the binding of S. mutans to teeth. These findings delineate the S. mutans proteome targeted by the immune system and suggest that the inhibition of bacterial adherence to teeth is a primary mechanism employed by the immune system to maintain oral balance and prevent caries formation.

CONCLUSIONS

These findings enhance our knowledge of the immune system's function in oral health maintenance and caries prevention, shedding light on how immunoglobulins interact with S. mutans proteins.

CLINICAL SIGNIFICANCE

Targeting S. mutans proteins implicated in bacterial adhesion could be a promising strategy for preventing childhood caries.

Beta Elemene induces cytotoxic effects in FLT3 ITD-mutated acute myeloid leukemia by modulating apoptosis

OBJECTIVE: β-Elemene, a sesquiterpene with a broad anti-cancer spectrum, is particularly effective against drug-resistant and complex tumors. It can also be efficient against FLT3-expressed acute myeloid leukemia. This research aims to determine whether β-Elemene has cytotoxic effects on FLT3 ITD-mutated AML cells. MATERIALS AND METHODS: Cytotoxicity, cell morphology, mRNA analysis with apoptotic markers, and analysis of 43 distinct protein markers related to cell death, survival, and resistance were all performed to elucidate its mechanism. Additionally, in order to understand how β-Elemene and FLT3 interact, molecular docking, molecular dynamics simulations, and computational ADME investigations were performed. RESULTS: β-Elemene exhibited cytotoxic activity against FLT3-mutated MV4-11 and FLT3 wild-type THP-1 cells, with an IC50 of around 25 µg/ml. The molecular studies revealed that β-Elemene inhibited cell proliferation by inducing p53, and the involvement of p21, p27, HTRA, and HSPs were also demonstrated. The interactive inhibition in proliferation was confirmed via molecular docking and dynamics analyses. β-Elemene occupied the FLT3 enzymatic pocket with good stability at the FLT3 active site. CONCLUSIONS: We concluded from our observations that β-Elemene causes cell death in ITD mutant AML cells, together with the effects of stress factors and inhibiting cell division.

Single-cell transcriptomic analysis of oral masticatory and lining mucosa-derived mesenchymal stromal cells

AIM

To reveal the heterogeneity of ex vivo-cultured human mesenchymal stromal cells derived from either masticatory or lining oral mucosa.

MATERIALS AND METHODS

Cells were retrieved from the lamina propria of the hard palate and alveolar mucosa of three individuals. The analysis of transcriptomic-level differences was accomplished using single-cell RNA sequencing.

RESULTS

Cluster analysis clearly distinguished between cells from the masticatory and lining oral mucosa, and revealed 11 distinct cell sub-populations, annotated as fibroblasts, smooth muscle cells or mesenchymal stem cells. Interestingly, cells presenting a mesenchymal stem cell-like gene expression pattern were predominantly found in masticatory mucosa. Although cells of masticatory mucosa origin were highly enriched for biological processes associated with wound healing, those from the lining oral mucosa were highly enriched for biological processes associated with the regulation of epithelial cells.

CONCLUSIONS

Our previous work had shown that cells from the lining and masticatory oral mucosae are phenotypically heterogeneous. Here, we extend these findings to show that these changes are not the result of differences in averages but rather represent two distinct cell populations, with mesenchymal stem cells more common in masticatory mucosa. These features may contribute to specific physiological functions and have relevance for potential therapeutic interventions.

The effect of Hericium erinaceum on the prevention of chemically induced experimental colitis in rats

BACKGROUND/AIMS

The aim of this study is to investigate the effects of the Hericium erinaceum on an experimental colitis model.

METHODS

Twenty-four Wistar albino were included in this study. Rats were divided into three groups. Group 1 (n = 8) was sham group. Group 2 is the group of chemically induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS) resulting in colitis. Group 3 (n = 8) is the group that was treated 7 days before and 7 days after with H. erinaceum resulting in colitis. The activity of colitis was evaluated macroscopically and microscopically in rats. In other words, nitric oxide (NO) levels, malondialdehyde (MDA), interleukin 6 (IL-6), nuclear factor-kappa B (NF-κB) and, tumor necrosis factor-α (TNF-α) in addition to the myeloperoxidasem (MPO) activities was determined.

RESULTS

The rate of TNBS-induced colitis caused to increase the level of MDA activities meaningfully in the colitis group than the control group. The results indicated that MDA (p = 0.001), NO (p = 0.001), IL-6 (p = 0.001), MPO (p = 0.878), TNF-α (p = 0.001), and NF-κB levels of treatment group decreased in the blood and colon tissues because of the H. erinaceum treatment when compared to the colitis group. H. erinaceum treatment was related to the declining of MDA, NF-κB, NO, IL-6, and TNF-α levels.

CONCLUSION

H. erinaceum had a positive effect on the colitis by reducing oxidative damage in blood and tissue.

Accelerated degradation of collagen membranes in type 1 diabetic rats is associated with increased expression and production of several inflammatory molecules

BACKGROUND

Membrane durability is critical for regenerative procedures. We reported previously that type 1-like diabetes in rats accelerates the degradation of collagen membranes and we tested here whether this is associated with increased local production of inflammatory molecules as part of a diabetes-induced chronic inflammation around and within the membranes.

METHODS

Collagen membrane discs were implanted under the scalp in diabetic (streptozotocin-induced) and control rats, which were sacrificed after 2 or 3 weeks. Total RNA and proteins were isolated from the membrane and its surrounding tissues and the expression and production of six inflammatory molecules (interleukin-6 [IL-6], tumor necrosis factor alpha [TNFα], matrix metalloproteinase [MMP]-9, macrophage migration inhibitory factor [MIF], MIP-1α, and MIP-2α) was measured using real-time PCR and western blotting, respectively. Minimal histological analysis of the membranes was conducted to conform to previous studies.

RESULTS

Hyperglycemia resulted in reduced membrane thickness (by 10% to 25%) and increased mononuclear infiltrate inside the membrane. mRNA and protein levels of IL-6, TNFα, and MMP-9 were elevated in diabetic rats both 2 and 3 weeks post-surgery. The levels (both mRNA and protein) of MIF were increased at 2 weeks post-surgery and those of MIP-1α and MIP-2α at 3 weeks. There was a very good match in the temporal changes of all examined genes between the mRNA and protein levels.

CONCLUSIONS

Elevated local production of inflammatory cytokines and MMPs, together with apparent mononuclear infiltrate and increased collagenolysis confirm that hyperglycemia leads to a chronic inflammation in and around the implanted collagen membranes, which reduces membrane longevity.

Clinical Significance of Intraoperative Frozen Section Analysis of Pancreatic Cancer Surgical Margin at the Time of Pancreaticoduodenectomy

BACKGROUND

Today, in the management of pancreas cancers, achieving an R0 resection is one of the most powerful independent predictors of long-term survival. The aim of this study is to assess the clinical significance of intraoperative frozen section analysis of the pancreatic surgical margin for pancreatic cancer during pancreaticoduodemectomy.

MATERIAL AND METHODS

We conducted a retrospective analysis of prospectively collected data of 37 patients who were operated for pancreatic head cancer and who were evaluated for surgical margin by frozen section analysis intraoperatively, between September 2013 and August 2014 in our center. The intraoperative biopsy reports were compared with final pathological reports.

RESULTS

The mean age of the patients was 64.55(19-82) years (range), the mean tumor size was 3.96(1.16-6.25) cm (range) and the mean harvested lymph node number was 18.52(9-45) (range). In the intraoperative frozen section, one patient was positive for surgical margin (%2.7) who underwent total or complementary pancreatectomy.

CONCLUSION

To secure a tumor-free margin by frozen section, intraoperatively, may increase R0 resection rate in pancreas cancers. The preoperative estimation of tumor margin by endoscopic ultrasonography, computerized tomography or magnetic resonance imaging mostly correlate with intraoperative findings, however in suspected cases intraoperative frozen section for margin determination should be performed.

Use of ductoscopy as an additional diagnostic method and its applications in nipple discharge

AIM

About 1/10 of the patients apply to breast clinics with the complaint of nipple discharge (ND). Surgery is the most frequently preferred treatment method in case of suspicious ND. The contribution of ductoscopy to identify the patients who are candidates for surgery was evaluated and its role to limit the surgery was assessed.

METHODS

From November 2005 to December 2010 430 patients with ND were assessed by 456 ductoscopic investigations and the results were analyzed. Complete ductoscopic evaluation was achieved in 84% of cases and 28 patients were offered surgery but did not accept (N.=355). Patients with bloody or serous discharges from a single duct were investigated by ductoscopy under local anesthesia as an office procedure. The patients were grouped according to discharge characteristics and the ductoscopic diagnoses.

RESULTS

A total of 223 patients had all three criteria of pathologic ND (PND: single duct, spontaneous and bloody/serous discharge). Twenty-two potential neoplastic or malignant lesion (PNML) and 79 papillomatous lesion (solitary or multiple papilloma) were identified. In 132 patients with just two of the PND criteria, 5 PNML and 18 papillomatous lesions were identified. Twenty-three patients with solitary papilloma that were removed by ductoscopic papillomectomy (DP) are followed up without surgery.

CONCLUSION

Ductoscopy helped to identify the patients who required surgical treatment and decreased the number of operations. DP was successfully performed in select group of patients who otherwise would have required surgical resection. Patients with normal ductoscopy findings and patients who were treated with DP successfully can be followed up without the need of surgery.

P5-05-05: Human Papiloma Virus Identification in Intraductal Papilloma and Breast Cancer Using Broad-Spectrum Primers

Background

There is limited data about Human Papiloma Virus (HPV) presence in intraductal papilloma, and there are some conflicted studies about the effects of HPVs on breast cancer. Most of these studies have methodological pitfalls as well. We conducted a retrospective paraffin block study to understand the presence of HPV in papilloma and cancer tissues with broad-spectrum primers.

Methods: Twenty seven intraductal papilloma and 18 breast cancer patients’ paraffin blocks were obtained from the patients who underwent ductoscopy aided papillomectomy or mastectomy. In totally 87 histopathological samples, HPV-DNA were identified by real time PCR and broad-spectrum genotyping was performed by in situ hybridization. The cancer patients were evaluated according to the status of Estrojen Reseptor (ER), Progesteron Reseptor (PR) and ErbB-2 positivity.

Results: The mean age±SD was 49±16 in papilloma and 52±14 in breast cancer patients. We found that 29.6% (8 of 27) of intraductal papillomas and 44.4% (8 of 18) of breast cancer paraffin blocks had HPV-DNA positivity by PCR in situ hybridization with broad spectrum primers. Fifty percent (4 of 8) of HPV-DNA positive papillomas had only type 11; in one, only type 6; in one, mixture of type 6,11; in one, mixture of type 11, 39; and in one, mixture of type 11, 39, 82 was detected. Breast cancer lesions had only type 11 of HPV-DNA positivity in 62.5% (5 of 8) of cases; in one, mixture of type11, 39; in one, mixture of type 11, 82; in one, mixture of type 6, 11, 39 was detected. In seven HPV-DNA positive cancer patients, ER/PR and/or ErbB-2 was positive, but it was only positive in one triple negative patient.

Conclusion: HPVs may have a role in developing papilloma and breast cancer. Validation of HPVs role in the etiology of breast cancer/papilloma, require further studies to understand whether the HPVs are episomal or integrated during the tumorigenesis.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-05-05.

Tc-99m radio-guided completion thyroidectomy for differentiated thyroid carcinoma

Background:

The purpose of this study is to investigate whether or not radio-guided surgery has any beneficial effects on completion thyroidectomy (CT) and the associated complication rates.

Patients and Methods:

Twenty-seven patients were scheduled for CT, for thyroid carcinoma, from December 2004 to June 2005, and were included in the study. All the patients had had initial thyroid surgery in other centers and been referred to our clinic for CT. Operation findings and the effectiveness of Tc-99m radio-guided CT were analyzed.

Results:

The intraoperative mean ratio of thyroid activity to background activity counted with a gamma probe was 1.3 ± 0.3. Average operation timing was 74 ± 9 minutes. Postoperatively, no residual tissue was detected in any of the patients with ultrasonography and thyroid scintigraphy. In the first postoperative month, serum TSH level was 61 ± 16.4 mIU / L, when preoperatively it was 7.3 ± 3.1 mIU / L (P < 0.001). In the postoperative period, one patient experienced temporary hypoparathyroidism (3.9%). Permanent hypoparathyroidism or recurrent laryngeal nerve damage was not detected in any patient.

Conclusion:

Tc-99 radio-guided CT is a reliable surgical method, which provides the detection and removal of residual thyroid tissues with minimal complications.

The efficacy of (99m)Tc-MIBI scintimammography in the evaluation of breast lesions and axillary involvement: a comparison with X-rays mammography, ultrasonography and magnetic resonance imaging

This study was performed because the efficacy of technetium-99m methoxyisobutyl isonitrile scintimammography ((99m)Tc-MIBI-SM) in the evaluation of the breast lesions and axillary lymph node involvement in comparison with X-rays mammography (XRM), ultrasonography (US) and magnetic resonance imaging (MRI) has not been fully investigated. Forty six female patients were included in this study, with suspicious lesions detected in their breasts by palpation, by imaging modalities or clinically. All patients underwent (99m)Tc-MIBI-SM, US and MRI for the evaluation of breast lesions. All patients according to clinical situation and imaging studies underwent fine needle aspiration, mass extirpation, core biopsy, modified radical mastectomy or partial lumpectomy in order to confirm the nature of the lesions. Our results showed that (99m)Tc-MIBI-SM detected 15 of 16, US 11 of 16, XRM 13 of 16 and MRI 13 of 16 malignant lesions. Sensitivities were 93%, 68%, 81% and 81%, respectively. Among these cases there were 4 of 15 false positive (FP) results on SM whereas 4 of 11 on US, 11 of 13 on XRM and 8 of 13 on MRI. The specificities of the above modalities were 86%, 87%, 63% and 73%, respectively. The sensitivities of the above imaging modalities for the detection of axillary lymph node metastases were 55%, 55%, 11% and 77% for SM, US, XRM and MRI, respectively. The sensitivity and specificity of SM for the palpable lesions (n=31) were 100% and 84% and for the nonpalpable lesions (n=15) were 75% and 90%, respectively. In conclusion, although the number of patients studied was small it is the opinion of the authors that (99m)Tc-MIBI-SM has a much better sensitivity and less FP results in detecting malignant breast lesions than the other 3 modalities and also better sensitivity than XRM and MRI. Thus (99m)Tc-MIBI-SM can be included in the diagnostic algorithms for detecting malignancy in breast tumors.

Ductoscopy in the evaluation and management of nipple discharge

BACKGROUND

Nipple discharge is a relatively common complaint among patients visiting specialized outpatient clinics for disease of the breast. With advancing technology, it became possible to diagnose and manage nipple discharge using minimally invasive procedures. The aim of this study is to report our experience with ductoscopic evaluation of patients with nipple discharge.

MATERIALS AND METHODS

Between September 2005 and February 2009, 236 patients with complaint of nipple discharge were admitted prospectively into the study. All patients were evaluated with ductoscopy. Data concerning age, ductoscopic and postsurgical diagnosis, duration, and complications with the procedure were statistically analyzed.

RESULTS

For 236 patients evaluated, there were 249 ductoscopic investigations. Of these, 39 patients were found to have intraductal solitary papilloma of which 24 were excised ductoscopically. Of the 24 ductoscopically excised solitary papillomas, it was possible to remove 17 completely, but 7 papillomas could be removed partially. For 13 patients with solitary papillomas large enough or unfavorably localized so that they could not be snare-excised and for 14 patients with multiple papillomas, we offered surgical removal of the lesions by limited excision of the ducts with the help of ductoscopic localization and marking. There were 35 patients who had debris within the canalicular system, and the debris was washed out. Ductoscopy revealed atypical ductal hyperplasia in 3 patients, ductal carcinoma in situ in 6 patients, and invasive carcinoma in 3 patients; all patients underwent surgery.

CONCLUSIONS

We believe that, as the technology quickly improves, ductoscopy will become more widely accepted and applied for breast disorders, not only as a diagnostic tool but also as a privileged therapeutic option for certain pathologies.

Diagnostic problems with parasitic and non-parasitic splenic cysts

BACKGROUND

The splenic cysts constitute a very rare clinical entity. They may occur secondary to trauma or even being more seldom due to parasitic infestations, mainly caused by ecchinocccus granulosus. Literature lacks a defined concencus including the treatment plans and follow up strategies, nor long term results of the patients. In the current study, we aimed to evaluate the diagnosis, management of patients with parasitic and non-parasitic splenic cysts together with their long term follow up progresses.

METHODS

Twenty-four patients with splenic cysts have undergone surgery in our department over the last 9 years. Data from eighteen of the twenty-four patients were collected prospectively, while data from six were retrospectively collected. All patients were assessed in terms of age, gender, hospital stay, preoperative diagnosis, additional disease, serology, ultrasonography, computed tomography (CT), cyst recurrences and treatment.

RESULTS

In this study, the majority of patients presented with abdominal discomfort and palpable swelling in the left hypochondrium. All patients were operated on electively. The patients included 14 female and 10 male patients, with a mean age of 44.77 years (range 20-62). Splenic hydatid cysts were present in 16 patients, one of whom also had liver hydatid cysts (6.25%). Four other patients were operated on for a simple cyst (16%) two patients for an epithelial cyst, and the last two for splenic lymphangioma. Of the 16 patients diagnosed as having splenic hydatit cysts, 11 (68.7%) were correctly diagnosed. Only two of these patients were administered benzimidazole therapy pre-operatively because of the risk of multicystic disease The mean follow-up period was 64 months (6-108). There were no recurrences of splenic cysts.

CONCLUSION

Surgeons should keep in mind the possibility of a parasitic cyst when no definitive alternative diagnosis can be made. In the treatment of splenic hydatidosis, benzimidazole therapy is not necessary, although it is crucial to perform splenectomy without rupturing and spilling the cysts.

Gamma probe (99m)Tc-pertechnetate assisted completion thyroidectomy vs conventional thyroidectomy in differentiated thyroid carcinoma

Patients undergoing partial thyroidectomy for benign diseases may need re-operation if differentiated thyroid carcinoma (DTC) is detected on histopathology. The aim of this study was to determine if using gamma probe during the above surgery in a procedure called: gamma probe completion thyroidectomy (GPCT) could support the diagnosis of DTC tissue and offer an advantage in the surgical treatment of DTC patients. We have studied 100 patients who after bilateral subtotal thyroidectomy for benign disease in several hospitals, were found to have DTC histopathologically and referred to our clinic for subsequent re-operation. Of these, 50 underwent conventional completion thyroidectomy (Group I) and 50 underwent GPCT (Group II). We compared retrospectively Group I and Group II in terms of volume of residual thyroid tissue, thyroid stimulating hormone (TSH) values, complication rates and incidence of tumor found in the residual thyroid. Our results showed that one month postoperatively, TSH was significantly higher in Group II (P<0.001). Volumes of residual thyroid were also significantly less in Group II (P<0.000). Complications and the incidence of tumor cells found in the residual thyroid tissue between the groups were not statistically different (P>0.05). In conclusion, GPCT in patients with DTC significantly increased the success of this operation in localizing and removing residual thyroid tissue.

Scarless endoscopic papillomectomy of the breast

BACKGROUND

Efforts have been made to improve minimally invasive breast surgery techniques, resulting in less tissue damage and much better cosmetic results. We evaluated the therapeutic value of a new scarless operation, endoscopic papillomectomy (EP), in patients with pathologic nipple discharge (PND).

METHODS

Breast ductoscopy was performed on 126 women with PND. These patients underwent a variety of appropriate ductoscopy-assisted (DA) endosurgical interventions, combined with cytologic examinations. Success was determined by recurrence of PND and by standard radiological examinations.

RESULTS

Ductoscopy was successfully performed in 102 patients. Of these 102 patients, 26 had solitary papillomas (SP), 5 had multiple papillomas (MP), 11 had intraductal debris, and 1 had a ductal epithelial surface abnormality with positive cytology. Of the 26 polypoid lesions (cytology negative), 22 were excised endoscopically (endoscopic papillomectomy). Patients with MP underwent DA-microdochectomy. Except in one patient, all discharges disappeared. After a mean +/- SD follow-up time of 11.5 +/- 5.8 months (range 2-22 months), there were no recurrences of nipple discharge and no radiological results suggestive of malignancy. Thus, the therapeutic efficacy of EP in our study was 95.4% (21/22).

CONCLUSIONS

Ductoscopy is not only a diagnostic procedure, but is also therapeutic for breast papillomas. EP is a new scarless treatment option for patients with PND.

H pylori: Treatment for the patient only or the whole family?

AIM: To compare the effects of treatment of H pylori-infected individuals with the effects of treatment of individuals as well as all H pylori-infected family members.

METHODS: H pylori-positive patients with similar demographic specifications were prospectively randomized with respect to treatment, with a triple regimen of either patients and all H pylori-positive family members living together (groupI) or patients only (group II). Nine months after treatment, all patients were assessed for H pylori positivity.

RESULTS: There were 70 H pylori-positive patients in each group; patients in groupsIand II lived with 175 and 190 H pylori-positive relatives, respectively. Age, sex and H pylori positivity rate were similar in both groups of relatives. Nine months after 14 d standard triple therapy, H pylori positivity was 7.1% in groupIpatients and 38.6% in group II patients [P < 0.01, OR = 8.61 95% confidence interval (CI): 2.91-22.84].

CONCLUSION: The present results indicate bad environmental hygienic conditions and close intra-familial relationships are important in H pylori contamination. These findings indicate all family members of H pylori-positive individuals should be assessed for H pylori positivity, particularly in developing countries where H pylori prevalence is high; they also suggest patients, their spouses and all H pylori-positive family members of H pylori-positive individuals should be treated for H pylori infection.

Laparoscopic splenectomy and LigaSure

Laparoscopic splenectomy (LS) is a preferred choice, especially for hematologic diseases. We present the advantages of the use of LigaSure (energy-based equipment that works by applying a precise amount of bipolar energy and pressure to the tissue, achieving a permanent seal) for achieving a precise hemostasis, thus making the LS easier. We have performed LS using LigaSure on 10 patients (4 female, 6 male; mean age, 36 years [range, 16-58]) between December 2002 and August 2003. All patients had ITP. There were no conversion to open surgery. Mean dimensions of spleens were 99 x 49 mm (range, 85 x 36-118 x 60). Intraoperative blood loss was no more than 100 mL in any patients (range, 20-100; mean, 60). The average operative time was 93 minutes (range, 60-155). There were no complications in the postoperative period. The average postoperative stay was 4.3 days (range, 3-7). LS using LigaSure is a safe and time-sparing procedure with almost no complications in this small initial series.

Biochemical characterization of the vanilloid receptor 1 expressed in a dorsal root ganglia derived cell line

The vanilloid receptor VR1 is an ion channel predominantly expressed by primary sensory neurons involved in nociception. Here we describe its biochemical properties and assess the subcellular localization, the glycosylation state and the quaternary structure of VR1 expressed in HEK293 cells and in the DRG-derived cell line F-11 (N18TG2 mouse neuroblastoma x rat dorsal root ganglia, hybridoma). VR1 was found to be glycosylated in both cell types. Of the five potential N-glycosylation sites, the predicted transient receptor potential channel-like transmembrane folding proposes N604 is localized extracellularly. We used site-directed mutagenesis to mutate the Asn at position 604 to Thr. This mutated VR1 was not glycosylated, confirming the extracellular location of N604 and its role as the exclusive site of glycosylation of the VR1 protein. VR1 occured in high molecular mass complexes as assessed by blue native PAGE. In the presence of limited amounts of SDS dimers, trimers and tetramers of VR1 were observed, consistent with the predicted tetrameric quaternary structure of the receptor. Cross-linking with dimethyladipimidate yielded almost exclusively dimers. Whereas VR1 localized both to the plasma membrane and to intracellular membranes in HEK293 cells, it localized predominantly to the plasma membrane in F-11 cells. Using confocal laserscanning microscopy, we observed an enrichment of anti-VR1 immunoreactivity in neurite-like structures of F-11 cells. In the light of conflicting literature data on biochemical characteristics of VR1, our data suggest that dorsal root ganglion-derived F-11 cells provide a powerful experimental system for the study of VR1 biochemistry.

Intraoperative bowel irrigation improves anastomotic collagen metabolism in the left-sided colonic obstruction but not covering colostomy

This study investigated the effects of intraoperative colonic irrigation and proximal diverting end colostomy after segmental bowel resection in experimental left-colonic obstruction on anastomotic healing. Simple obstruction of descending colon was performed in male Sprague-Dawley rats. After 24 h we performed segmental colonic resection and anastomosis in the control group (n = 15); resection, anastomosis, and covering colostomy in the colostomy group (n = 14); resection and anastomosis after antegrade colonic lavage through cecum by using isotonic saline solution in the irrigation group (n = 13). In rats that were killed 7 days later anastomotic dehiscence and bursting pressure and tissue hydroxyproline concentration at the anastomosis were measured. No significant differences were observed between groups in terms of anastomotic dehiscence, bursting site, or pressure. The hydroxyproline concentration was significantly higher in the irrigation group than the control group (P = 0.025) and the colostomy group (P = 0.029), but no difference was noted between the control group and the colostomy group. These findings suggest that intraoperative antegrade colonic irrigation in the acute left-sided colonic obstruction positively affects collagen metabolism at the anastomotic site; if the anastomosis is performed without bowel cleansing, covering colostomy does not improve collagen metabolism.

The Fanconi anaemia group G gene FANCG is identical with XRCC9

Fanconi anemia (FA) is an autosomal recessive disease with diverse clinical symptoms including developmental anomalies, bone marrow failure and early occurrence of malignancies. In addition to spontaneous chromosome instability, FA cells exhibit cell cycle disturbances and hypersensitivity to cross-linking agents. Eight complementation groups (A-H) have been distinguished, each group possibly representing a distinct FA gene. The genes mutated in patients of complementation groups A (FANCA; refs 4,5) and C (FANCC; ref. 6) have been identified, and FANCD has been mapped to chromosome band 3p22-26 (ref. 7). An additional FA gene has recently been mapped to chromosome 9p (ref. 8). Here we report the identification of the gene mutated in group G, FANCG, on the basis of complementation of an FA-G cell line and the presence of pathogenic mutations in four FA-G patients. We identified the gene as human XRCC9, a gene which has been shown to complement the MMC-sensitive Chinese hamster mutant UV40, and is suspected to be involved in DNA post-replication repair or cell cycle checkpoint control. The gene is localized to chromosome band 9p13 (ref. 9), corresponding with a known localization of an FA gene.

Identification of a HeLa mRNA fraction which corrects the mitomycin C sensitivity of irs1 cells

The hamster cell mutant irs1 is defective in its response to DNA lesions caused by a variety of mutagens, particularly cross-linking agents. These cells have been assigned to complementation group 2 of X-ray-sensitive mutants and the mutated gene is called XRCC2(X-ray repair cross complementing). We have identified, by microinjection, a human mRNA fraction which can transiently correct the sensitivity of these cells to cross-linking agents. This fraction contains mRNAs of 3.5 kb (+/- 0.25) including, therefore, the transcript of the XRCC2 gene.