Randomized clinical trial of short or long interval between neoadjuvant chemoradiotherapy and surgery for rectal cancer.

BACKGROUND: The optimal timing of surgery following preoperative chemoradiotherapy (CRT) is controversial. This trial aimed to compare pathological complete response (pCR) rates obtained after an interval of 8 weeks or less versus more than 8 weeks. METHODS: Patients with locally advanced rectal adenocarcinoma situated within 12 cm of the anal verge (T3-4 or N+ disease) were randomized to undergo total mesorectal excision (TME) within 8 weeks (classical interval, CI group) or after 8 weeks (long interval, LI group) following CRT. RESULTS: Among the 327 included patients (CI 160, LI 167), the pCR rate was significantly higher in the LI group than in the CI group (10·0 versus 18·6 per cent; P = 0·027). The highest pCR rate (29 per cent) was observed between 10 and 11 weeks. There was statistically significant disease regression in the LI group, with better stage (P = 0·004) and T category (P = 0·001) than in the CI group. There was no significant difference in surgical quality (rates of tumour-positive margins, TME quality, anastomotic leakage and intraoperative perforation) between the groups. The overall morbidity rate was 22·5 per cent in the CI group and 19·8 per cent in the LI group (P = 0·307). Regression analysis including sex, age, clinical stage, tumour location, tumour differentiation, TME quality, concomitant chemotherapy and interval to surgery revealed no statistically significant predictors of pCR. CONCLUSION: Disease regression and pCR rate are increased with an interval between CRT and surgery exceeding 8 weeks. Registration number: NCT03287843 (http://www.clinicaltrials.gov).

May supplementation of coenzyme Q10 help prevent development of hydatidiform mole?.

OBJECTIVE: The pathological mechanisms of gestational trophoblastic disease have not yet been clearly determined. It is thought that oxidative damage contributes to the process. The aim of this study was to determine the levels of coenzyme Q10 (CoQ 10), DNA damage, and lipid peroxidation in patients with hydatidiform mole. MATERIALS AND METHODS: The authors studied the levels of CoQ10, 8-hydroxydeoxyguanosine (8-OHdG), malondialdehyde (MDA) by high-performance liquid chromatography (HPLC), and the activity of glutathione peroxidase (GPX) by spectrophotometric method in blood obtained from patients with a complete hydatidiform mole (n=29), healthy pregnant women (n=29), and healthy non-pregnant women (n=29). RESULTS: The 8-OHdG/dG ratio (2.8148 ± 0.81592) and MDA (10.8341 ± 4.64875 µmol) were significantly higher in patients with complete hydatidiform mole, while the ubiquinol-10/ubiquinone-10 ratio (0.2107 ± 0.15675) and GPX activity (43.4606 ± 18.31694 mU/mI) were lower (p < 0.001). CONCLUSION: The authors suggest that both mitochondrial oxidative and oxidative DNA damage play important roles in the pathogenesis of complete hydatidiform mole. Therefore supplementation of CoQ10 prevents recurrent gestational trophoblastic disease.

Local application of gingiva-derived mesenchymal stem cells on experimental periodontitis in rats.

BACKGROUND: Stem cell-based approaches in regenerative periodontal therapy have been used in different experimental models. In this study, the effect of local application of gingival mesenchymal stem cells (GMSC) in fibroin/chitosan oligosaccharide lactate hydrogel (F/COS) on periodontal regeneration was evaluated using experimental periodontitis model in rats. METHODS: Mesenchymal stem cells were isolated from the gingiva of rats and characterized. Viability tests and confocal imaging of GMSC in hydrogels were performed. Healthy control without periodontitis (Health; H; n=10), control with periodontitis but no application (Periodontitis; P; n=10), only hydrogel application (F/COS; n=10), and GMSC+F/COS (n=10) four groups were formed for in vivo studies. Experimental periodontitis was created with silk sutures around the maxillary second molars. GMSC labeled with green fluorescent protein (GFP) (250,000 cells/50 µL) in F/COS were applied to the defect. Animals were sacrificed at 2nd and 8th weeks and maxillae of the animals were evaluated by micro-computed tomography (micro-CT) and histologically. The presence of GFP-labeled GMSC was confirmed at the end of 8 weeks. RESULTS: Micro-CT analysis showed statistically significant new bone formation in the F/COS+GMSC treated group compared with the P group at the end of 8 weeks (p < 0.05). New bone formation was also observed in the F/COS group, but the statistical analysis revealed that this difference was not significant when compared with the P group (p > 0.05). Long junctional epithelium formation was less in the F/COS+GMSC group compared with the P group. Periodontal ligament and connective tissue were well-organized in F/COS+GMSC group. CONCLUSION: The results showed that local GMSC application in hydrogel contributed to the formation of new periodontal ligament and alveolar bone in rats with experimental periodontitis. Since gingiva is easly accessible tissue, it is promising for autologous cell-based treatments in clinical applications.

Identification of candidate biomarkers in converting and non-converting clinically isolated syndrome by proteomics analysis of cerebrospinal fluid.

Multiple sclerosis (MS) often starts in the form of clinically isolated syndrome (CIS) and only some of the CIS patients progress to relapsing-remitting MS (RRMS). Biomarkers to predict conversion from CIS to MS are thus greatly needed for making correct treatment decisions. To identify a predictive cerebrospinal fluid (CSF) protein, we analyzed the first-attack CSF samples of CIS patients who converted (CIS-MS) (n = 23) and did not convert (CIS-CIS) (n = 19) to RRMS in a follow-up period of 5 years using proteomics analysis by liquid chromatography tandem-mass spectrometry (LC-MS/MS) and verified by ELISA. Label-free differential proteomics analysis of CSF ensured that 637 proteins were identified and 132 of these proteins were found to be statistically significant. Further investigation with the ingenuity pathway analysis (IPA) software led to identification of three pathway networks mostly comprised proteins involved in inflammatory response, cellular growth and tissue proliferation. CSF levels of four of the most differentially expressed proteins belonging to the cellular proliferation network function, chitinase-3-like protein 1 (CHI3L1), tumor necrosis factor receptor superfamily member 21 (TNFRSF21), homeobox protein Hox-B3 (HOXB3) and iduronate 2-sulfatase (IDS), were measured by ELISA. CSF levels of HOXB3 were significantly increased in CIS-MS patients. Our results indicate that cell and tissue proliferation functions are dysregulated in MS as early as the first clinical episode. HOXB3 has emerged as a potential novel biomarker which might be used for prediction of CIS-MS conversion.

Palindrome resolution and recombination in the mammalian germ line.

Genetic instability is promoted by unusual sequence arrangements and DNA structures. Hairpin DNA structures can form from palindromes and from triplet repeats, and they are also intermediates in V(D)J recombination. We have measured the genetic stability of a large palindrome which has the potential to form a one-stranded hairpin or a two-stranded cruciform structure and have analyzed recombinants at the molecular level. A palindrome of 15.3 kb introduced as a transgene was found to be transmitted at a normal Mendelian ratio in mice, in striking contrast to the profound instability of large palindromes in prokaryotic systems. In a significant number of progeny mice, however, the palindromic transgene is rearranged; between 15 and 56% of progeny contain rearrangements. Rearrangements within the palindromic repeat occur both by illegitimate and homologous, reciprocal recombination. Gene conversion within the transgene locus, as quantitated by a novel sperm fluorescence assay, is also elevated. Illegitimate events often take the form of an asymmetric deletion that eliminates the central symmetry of the palindrome. Such asymmetric transgene deletions, including those that maintain one complete half of the palindromic repeat, are stabilized so that they cannot undergo further illegitimate rearrangements, and they also exhibit reduced levels of gene conversion. By contrast, transgene rearrangements that maintain the central symmetry continue to be unstable. Based on the observed events, we propose that one mechanism promoting the instability of the palindrome may involve breaks generated at the hairpin structure by a hairpin-nicking activity, as previously detected in somatic cells. Because mammalian cells are capable of efficiently repairing chromosome breaks through nonhomologous processes, the resealing of such breaks introduces a stabilizing asymmetry at the center of the palindrome. We propose that the ability of mammalian cells to eliminate the perfect symmetry in a palindromic sequence may be an important DNA repair pathway, with implications regarding the metabolism of palindromic repeats, the mutability of quasipalindromic triplet repeats, and the early steps in gene amplification events.

Isolated perianal tuberculosis.

Perianal tuberculosis, without the presence of any previous or active pulmonary infection, is extremely rare. A case of isolated perianal tuberculosis without gastrointestinal or pulmonary spread will be discussed here with an evaluation of the clinical features.

Effects of N-acetylcysteine treatment on oxidative stress in acetic acid-induced experimental colitis in rats.

We assessed the possible protective effects of N-acetylcysteine (NAC) against toxic damage in the rat colon. Two doses of NAC (20 mg/kg and 100 mg/kg) given for 2 days and 7 days after acetic acid administration (to induce colitis) were tested. NAC was dissolved in saline and administered locally (intracolonic), systemically (intraperitoneal) or in a combination (intracolonic and intraperitoneal). Several parameters, including macroscopic and histopathological scores and myeloperoxidase, glutathione and nitric oxide concentrations were measured using standard assay procedures. Treatment with 100 mg/kg NAC for 7 days significantly decreased tissue myeloperoxidase, glutathione and nitric oxide concentrations. The 20 mg/kg dose had no protective effects. The data indicate that NAC substantially reduced the degree of colonic injury, probably by regulating free radical production and inhibiting inflammation. It may, therefore, have a role in the treatment of inflammatory bowel disease.

The activities of serum paraoxonase and arylesterase and lipid profile in acute myeloid leukemia: preliminary results.

OBJECTIVE: To investigate the activities of serum paraoxonase-1 (PON1) and arylesterase (ARE), and the lipid profile in newly diagnosed acute myeloid leukemia (AML) patients. PATIENTS AND METHODS: Thirty-two persons (16 of AML and 16 of healthy control) were included to the study. PON1 and ARE activities were measured as spectrophotometrically in serum samples. High density lipoprotein (HDL), low density lipoprotein (LDL), total cholesterol (TC), triglyceride (TG) were analyzed in autoanalyzer. RESULTS: PON1 activities were respectively 16.04 U/L and 18.6 U/L in AML and healthy controls. There was no statistical significance between groups (p > 0.05). The mean ARE activities were respectively 0.21 U/L and 0.36 U/L in AML and healthy controls. Serum ARE activity significantly decreased in AML group (p < 0.001). Serum HDL values were significantly decreased (181.8 ± 76.2 mg/dl; p = 0.002) in AML. There was no difference in total cholesterol, LDL and triglyceride values (respectively; 181.8 ± 76.2 mg/dl, 120.6 ± 64.6 mg/dl, 157.3 ± 87.2 mg/dl; p > 0.05) between AML and controls. CONCLUSIONS: This is the first documented study about serum PON1 activity in AML patients. Although serum PON1 activities were not changed in both groups, our data suggest that the decreased serum ARE activity and HDL levels may be related the pathogenesis of AML.

Somatostatin receptor subtype 1 modulates basal inhibition of growth hormone release in somatotrophs.

Somatostatin (SST) inhibits the secretion of many peptide hormones including growth hormone (GH). The various functions of SST are mediated through at least five different receptor subtypes (SSTR1-5), their precise physiological roles have not been solved yet. Here we report on studies concerning the functional role of SSTR1 in the modulation of GH release from somatotrophs. Primary cell cultures from pituitaries of wild-type SSTR1 mice exposed to the SSTR1 selective somatostatin analog CH-275 show reduction of basal levels of GH secretion whereas somatotrophs isolated from SSTR1 null mutant mice did not respond to the agonist-mediated effect. This suggests that SSTR1 is involved in modulating basal GH levels in primary pituitary cell cultures and, together with SSTR2, may control the secretion of GH in the body.

Palindromic DNA and genome stability. Further studies.

Unusual DNA structures promote genetic instability. One such example is hairpin DNA, which can form from palindromic sequences and triplet repeats, and is also a characteristic intermediate in V(D)J recombination. We previously found that a large 15.3-kb palindrome that was introduced as a transgene into the mouse germline was highly unstable. Although it could be transmitted, the transgene was found to be rearranged in up to 56% of the progeny, and rearrangement events often involved deletion at the center of symmetry. Here, the fine structure of centrally deleted palindromes was sampled by analysis of recombinant junctions isolated from testes DNA, providing further evidence for a model, previously proposed, that accounts for such deletions on the basis of a hairpin-tip nicking activity. In addition to central deletions, gene conversion events were also elevated in the transgenic palindrome. We have now analyzed instability in two mouse sublines in which (as a result of inversion) the transgenic palindrome had been shortened to 4.2 kb. In these sublines, the transgene was still subject to both rearrangement and gene conversion events at a high frequency, similar to the original 15.3-kb palindrome. Recombination was not limited to the sequences constituting the inverted repeat, but was seen to include sequences lying outside the palindrome. As discussed, the salient feature in all of these observations, a high level of genetic change associated with palindromic DNA, underscores the significance of hairpin DNA and hairpin-tip nicking in genome stability.

Binding potency of 6-nitroquipazine analogues for the 5-hydroxytryptamine reuptake complex.

The in-vitro inhibition constants (Ki) of nine structural analogues of the potent 5-hydroxytryptamine (5-HT)-uptake inhibitor, 6-nitroquipazine, were determined to assess the structure-affinity relationship of these derivatives. The goal of these studies was to determine those positions on 6-nitroquipazine that could be derivatized without significantly decreasing the affinity of the drug for the binding site, so that radiolabels such as 123I, 76Br or 18F might be appended for in-vivo imaging studies of the 5-HT reuptake system. Using bromine as a steric probe, the rank order of potency of bromine-substituted 6-nitroquipazine analogues for inhibiting the binding of [3H]paroxetine to the 5-HT reuptake binding site was: 8- < 3- < 7- < 4- < 5-bromo. The in-vitro equipotent molar ratio (EPMR, Ki (analogue)/Ki(6-nitroquipazine)) of the 5-bromo analogue was 0.57, indicating that this analogue had greater affinity for the 5-HT reuptake complex than 6-nitroquipazine. Derivatization at the 5-position with fluorine and iodine also resulted in potent compounds with EPMR values of 1.1 and 0.83, respectively. Substitution of quipazine with bromo, cyano, and formyl groups at the 6-position produced less potent compounds than the 6-nitro group. Based upon the high affinities of the 5-bromo-, 5-fluoro- and 5-iodo-6-nitroquipazines for the 5-HT reuptake complex, these compounds are candidates for radiolabeling for in-vivo studies of the 5-HT reuptake site.

Pancreatic Castleman's tumour: an unusual case.

We present an uncommon case of hyaline vascular type Castleman's disease mimicking a pancreatic tumour. A 56-year-old woman with constitutional symptoms was investigated. Pre-operative interventions failed to produce a definitive diagnosis. Surgical excision was performed and the tumour was diagnosed to be the hyaline vascular type of Castleman's disease histopathologically. Pancreatic Castleman's disease should remain a consideration in the differential diagnosis of a pancreatic mass.

Dexmedetomidine as a substitute for remifentanil in ambulatory gynecologic laparoscopic surgery.

OBJECTIVE: To compare dexmedetomidine with remifentanil in desflurane based ambulatory gynecologic laparoscopic surgery, in respect to its effects on orientation, discharge time, nausea-vomiting, and postoperative analgesic need. METHODS: Sixty 20-40 year old ASA I-II patients undergoing gynecologic laparoscopic surgery were randomized into 2 groups. This study was performed in the operating theaters of the Hacettepe University Faculty of Medicine, Hacettepe, Turkey in 2004 as a prospective, randomized, and double blinded study. The remifentanil group (group R), and dexmedetomidine group (group D) received a bolus of 1 microg/kg over 10 minutes, followed by 0.2 microg/kg/minute peroperative infusion of remifentanil, and 0.4 microg/kg/hour of dexmedetomidine. Hemodynamic parameters, time to extubation, and to orientation to person, place, and date, postoperative nausea, vomiting, pain, analgesic requirement at home, and satisfaction with anesthesia were recorded. RESULTS: Demographic, hemodynamic data, postoperative pain scores, and discharge time were similar in both groups. Time to extubation, to orientation to person, to place and date were shorter in group R. Postoperative nausea, vomiting, and analgesic requirements at home were less in group D. CONCLUSION: This study demonstrated that dexmedetomidine infusion causes a relatively slow recovery with reduced postoperative nausea, vomiting, and analgesic requirements, and similar hemodynamics compared to remifentanil in ambulatory laparoscopic surgeries. It may be an alternative to remifentanil in ambulatory anesthesia.

Determinants of retrovirus gene expression in embryonal carcinoma cells.

The expression of Moloney murine leukemia virus is restricted in embryonal carcinoma (EC) cells. To characterize specific mutations necessary for expression of retroviruses in EC cells, we analyzed the expression of retrovirus mutants and recombinants thereof in EC cell lines F9 and PCC4. DNA sequence comparison and functional studies allowed us to define three point mutations in the enhancer region of the viral mutants at positions -345, -326, and -166 and two point mutations within the 5'-untranslated region of the viral genome at positions +164 and +165 that were essential for retrovirus expression in EC cells. DNA fragments derived from either the wild type or mutant viruses were used to search for sequence-specific DNA-binding factors in nuclear extracts from undifferentiated PCC4 cells. A cellular factor was found to bind strongly to sequences within the enhancer region (-354 to -306) of wild-type viruses but only weakly to sequences derived from mutant viruses. This factor was named ECF-I (for EC cell factor I). Retroviral expression in EC cells correlates with decreased binding affinity for ECF-I.

Embryonic stem cell virus, a recombinant murine retrovirus with expression in embryonic stem cells.

The expression of Moloney murine leukemia virus and vectors derived from it is restricted in undifferentiated mouse embryonal carcinoma and embryonal stem (ES) cells. We have developed a retroviral vector, the murine embryonic stem cell virus (MESV), that is active in embryonal carcinoma and ES cells. MESV was derived from a retroviral mutant [PCC4-cell-passaged myeloproliferative sarcoma virus (PCMV)] expressed in embryonal carcinoma cells but not in ES cells. The enhancer region of PCMV was shown to be functional in both cell types, but sequences within the 5' untranslated region of PCMV were found to restrict viral expression in ES cells. Replacement of this region by related sequences obtained from the dl-587rev retrovirus results in MESV, a modified PCMV virus that confers G418 resistance to fibroblasts and ES cells with similar efficiencies. Expression of MESV in ES cells is mediated by transcriptional regulatory elements within the 5' long terminal repeat of the viral genome.

Repeat expansion by homologous recombination in the mouse germ line at palindromic sequences.

Genetic instability can be induced by unusual DNA structures and sequence repeats. We have previously demonstrated that a large palindrome in the mouse germ line derived from transgene integration is extremely unstable and undergoes stabilizing rearrangements at high frequency, often through deletions that produce asymmetry. We have now characterized other palindrome rearrangements that arise from complex homologous recombination events. The structure of the recombinants is consistent with homologous recombination occurring by a noncrossover gene conversion mechanism in which a break induced in the palindrome promotes homologous strand invasion and repair synthesis, similar to mitotic break repair events reported in mammalian cells. Some of the homologous recombination events led to expansion in the size of the palindromic locus, which in the extreme case more than doubled the number of repeats. These results may have implications for instability observed at naturally occurring palindromic or quasipalindromic sequences.

A model for testing recombinogenic sequences in the mouse germline.

Homologous recombination is a conserved process of genetic exchange generated by homologous pairing of nucleotides. Species diversity and gene evolution are dependent on the outcomes of recombination during germ cell development, yet systems to study mammalian germline recombination, especially those with applications to human genetics, are not well developed. We report on a transgenic mouse system designed to study recombination within test sequences in the male germline utilizing an intron-interrupted lacZ reporter gene. beta-galactosidase positive sperm are detected and quantitated by flow cytometry using fluorogenic substrates. Examination of recombination within a 1.7 kb repeat of test sequences derived from the human glycophorin breakpoint cluster region detects approximately 0.04-0.09% fluorescent sperm. Confirmation that these sperm result from recombination in the germline comes from histochemical staining of testicular cells, examination of spliced mRNA, and PCR analysis of sorted sperm populations. The system is readily adaptable to studies of other sequences reported to have elevated levels of recombination, including those implicated in human genetic disease. Investigations of the molecular basis for genomic instability at specific chromosomal locations may yield important insights into mechanisms of chromosomal loss and rearrangements.

[Occlusion of the gastric outlet caused by a trichobezoar]. / Magenausgangsverschluss durch einen Trichobezoar.

Bezoars are concretions formed in the gastrointestinal tract. The trichobezoars are hairballs in the stomach or intestines composed of hair. They are usually found in young girls as in our case which we operated in April 1989 on Surgical Ward in Kartal State Hospital in Istanbul. The postgastrectomy state predisposes to bezoar formation. Persimmon peels or pits, orange or grapefruit pulp are the usual offenders. Bezoars are associated with vague upper gastrointestinal discomfort, nausea, and vomiting. The patients may complain of abdominal pain. Ulceration, bleeding, obstruction, and perforation are the most common complications. Treatment consist of mechanical fragmentation via the endoscope or operative extraction. Dissolution of the undigested bolus by ingestion of proteolytic enzymes such as papain may be tried. As prophylaxis the postgastrectomy patient must be warned of ingesting citrus fruits.

Development of collaterals in intermittent and permanent ischemia of the liver.

The ischemia caused by the hepatic dearterialization as therapy for hepatic malignancies is transient because of the rapid formation of collaterals. In order to prevent this transient repeated ischemia has been suggested. An experimental study was planned to compare the collateral occurrence in persistent ischemia and transient repeated ischemia of the liver. Fourteen dogs (seven persistent ischemia, seven transient repeated ischemia) were used in this study. Hepatic dearterialization were performed in both groups. In the first group (persistent ischemia), the hepatic artery was ligated proximal to the gastroduodenal artery. In the second group (transient repeated ischemia), the hepatic artery was occluded externally in the same region as the first group by means of a device modified from 8 guage Foley catheter and after occlusion for one hour it was reopened. Occlusions were repeated twice in a day. Five dogs in the first group and six dogs in the second group completed a three week ischemia period and angiography were then performed in all. The dogs were sacrificed after the angiography and examined for possible abscess formation, arterial thrombosis, peritoneal adhesions and liver necrosis. After angiography, the two groups were also examined for collateral occurrence. Only one collateral occurred in the transient repeated ischemia group, but in the persistent ischemia group, collaterals occurred in all dogs. This difference between two groups is statistically significant (Fischer Absolute Chi Square Test, p = 0.013). Transient repeated ischemia is superior to persistent ischemia because of fewer collaterals, but in practise, total dearterialization of the liver is impossible.