Thermodynamic parameters for an expanded nearest-neighbor model for formation of RNA duplexes with Watson-Crick base pairs

Improved thermodynamic parameters for prediction of RNA duplex formation are derived from optical melting studies of 90 oligoribonucleotide duplexes containing only Watson-Crick base pairs. To test end or base composition effects, new sets of duplexes are included that have identical nearest neighbors, but different base compositions and therefore different ends. Duplexes with terminal GC pairs are more stable than duplexes with the same nearest neighbors but terminal AU pairs. Penalizing terminal AU base pairs by 0.45 kcal/mol relative to terminal GC base pairs significantly improves predictions of DeltaG degrees37 from a nearest-neighbor model. A physical model is suggested in which the differential treatment of AU and GC ends accounts for the dependence of the total number of Watson-Crick hydrogen bonds on the base composition of a duplex. On average, the new parameters predict DeltaG degrees37, DeltaH degrees, DeltaS degrees, and TM within 3.2%, 6.0%, 6.8%, and 1.3 degreesC, respectively. These predictions are within the limit of the model, based on experimental results for duplexes predicted to have identical thermodynamic parameters.

MicroRNAs and cancer stem cells: the sword and the shield

Emerging chemotherapy drugs and targeted therapies have been widely applied in anticancer treatment and have given oncologists a promising future. Nevertheless, regeneration and recurrence are still huge obstacles on the way to cure cancer. Cancer stem cells (CSCs) are capable of self-renewal, tumor initiation, recurrence, metastasis, therapy resistance, and reside as a subset in many, if not all, cancers. Therefore, therapeutics specifically targeting and killing CSCs are being identified, and may be promising and effective strategies to eliminate cancer. MicroRNAs (miRNAs, miRs), small noncoding RNAs regulating gene expression in a post-transcriptional manner, are dysregulated in most malignancies and are identified as important regulators of CSCs. However, limited knowledge exists for biological and molecular mechanism by which miRNAs regulate CSCs. In this article, we review CSCs, miRNAs and the interactions between miRNA regulation and CSCs, with a specific focus on the molecular mechanisms and clinical applications. This review will help us to know in detail how CSCs are regulated by miRNAs networks and also help to develop more effective and secure miRNA-based clinical therapies.

Transcriptome profiling of the whitefly Bemisia tabaci reveals stage-specific gene expression signatures for thiamethoxam resistance

Bemisia tabaci has developed high levels of resistance to many insecticides including the neonicotinoids and there is strong evidence that for some compounds resistance is stage-specific. To investigate the molecular basis of B. tabaci resistance to the neonicotinoid thiamethoxam we used a custom whitefly microarray to compare gene expression in the egg, nymph and adult stages of a thiamethoxam-resistant strain (TH-R) with a susceptible strain (TH-S). Gene ontology and bioinformatic analyses revealed that in all life stages many of the differentially expressed transcripts encoded enzymes involved in metabolic processes and/or metabolism of xenobiotics. Several of these are candidate resistance genes and include the cytochrome P450 CYP6CM1, which has been shown to confer resistance to several neonicotinoids previously, a P450 belonging to the Cytochrome P450s 4 family and a glutathione S-transferase (GST) belonging to the sigma class. Finally several ATP-binding cassette transporters of the ABCG subfamily were highly over-expressed in the adult stage of the TH-R strain and may play a role in resistance by active efflux. Here, we evaluated both common and stage-specific gene expression signatures and identified several candidate resistance genes that may underlie B. tabaci resistance to thiamethoxam.

Alcohol consumption alters dopamine transporter sites in Wistar–Kyoto rat brain

Even though animal and human studies show alterations in dopamine transporter (DAT) sites after alcohol withdrawal, the role of DAT in influencing either alcoholic or depressive behavior has not been examined extensively. Given that the Wistar-Kyoto (WKY) rat is a putative animal model of depressive behavior, the present study examined the effects of chronic alcohol consumption on DAT sites in WKY versus Wistar (WIS) rats. Brains from both strains were sectioned for autoradiographic analysis of [3H]-GBR12935 binding to DAT sites after 24 days of alcohol exposure. The results indicated that WKY rats consumed a greater amount of alcohol (P < 0.001) than WIS rats did throughout the experiment. Autoradiographic analyses of discrete brain regions indicated that alcohol consumption increased DAT sites in a greater number of brain areas in WKY compared to WIS rats. In WKY rats, the binding of [3H]-GBR12935 to DAT sites was increased in the basolateral, central and lateral nuclei of the amygdala, lateral nucleus of the hypothalamus, olfactory tubercle, caudate-putamen, nucleus accumbens and substantia nigra (P < 0.05) and decreased in the ventromedial nucleus of the hypothalamus and the CA1 region of the hippocampus. In WIS rats, alcohol consumption increased DAT sites in the CA1 region of the hippocampus, basolateral nucleus of the amygdala, ventral tegmental area and substantia nigra, and decreased DAT sites in the lateral and ventromedial hypothalamus and dentate gyrus. These results indicate a strain dependent alteration in DAT sites which may be related to altered dopamine neurotransmission in select brain regions following alcohol consumption.

Effect of sedative and hypnotic doses of propofol on the EEG activity of patients with or without a history of seizure disorders

Propofol is alleged to possess both pro- and anticonvulsant properties, leading to controversy regarding its use in patients with a history of seizures. Since propofol is administered for both sedation and hypnosis, it is important to understand the effects of low (0.5-1.0 mg/kg) and high (2-2.5 mg/kg) doses of propofol on the electroencephalogram (EEG). In this study, the hemodynamic and EEG effects of cumulative doses of propofol from 0.5 to 2.5 mg/kg i.v. were studied in 30 neurosurgical patients with or without a history of seizure disorders. While continuously recording from scalp EEG electrodes (F3, F4, C3, C4, P3, P4, O1, and O2), propofol 0.5 mg/kg was infused intravenously over 20 s. The same dose of propofol was reinjected four times at 2-min intervals, until a total dose of 2.5 mg/kg had been administered. The number and average amplitude of the EEG waves were counted and measured manually, respectively, from 80 to 90 s after beginning the injection of each dose of propofol. After lower propofol doses (0.5-1 mg/kg), the number of beta-waves increased, while alpha- and theta-waves decreased significantly in all patients. However, with larger doses of propofol (total dose of 2-2.5 mg/kg), the number of beta-waves decreased and delta-waves appeared. The amplitudes of all EEG waves increased and were maintained at a higher level after administration of propofol. Spike (or sharp) waves appeared in 33% of the control patients and in 40% of the epileptic group after propofol 0.5 mg/kg and in 73% of the control and 67% of the epileptic patients after the 1.5-mg/kg dose. In the majority of patients, the spike waves disappeared when additional doses of propofol were administered. One patient in the epileptic group had an EEG-recorded and clinical grand mal seizure after propofol 1 mg/kg, but the seizure disappeared after an additional 0.5-mg/kg bolus dose was administered. The propofol-induced EEG changes appeared initially at the frontal and central EEG electrodes and subsequently at the other EEG electrodes. Overall, there were no significant differences in the spectrum of EEG changes between the two patient populations. It is concluded that propofol produces similar dose-dependent effects on EEG activity in patients with or without a history of seizure disorders. While induction of anesthesia with higher doses of propofol (> 1.5 mg/kg) in neurosurgical patients with well controlled seizure disorder is safe, smaller sedative doses should be administered with caution to epileptic patients.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Identification, isolation, and characterization of a 32-kDa fatty acid-binding protein missing from lymphocytes in humans with Bietti crystalline dystrophy (BCD)

Bietti crystalline dystrophy (BCD) is an autosomal recessive retinal degeneration characterized by intraretinal lipid inclusions with degeneration of the retina and sclerosis of the choroidal vessels, resulting clinically in progressive night blindness and constriction of the visual fields. Characterization of fatty acid metabolism in Bietti crystalline dystrophy suggested that BCD might result from abnormalities in lipid-binding proteins or one or more enzymes active in fatty acid elongation and desaturation. To further investigate the first possibility, the docosahexaenoic acid-binding proteins (DHABPs) of human lymphocytes from patients with Bietti crystalline dystrophy were studied and compared with those of normal controls. For fatty acid-binding protein (FABP) identification, lymphocyte cytosol was first subjected to Lipidex 1000 chromatography. FABPs were then cross-linked with [14C]22:6n-3 and identified by HPLC and SDS-PAGE. Ten major peaks corresponding to calculated molecular weights of 13, 14, 32, 43, 45, 50, 64, 96, 105, and 186 kDa exhibit high-affinity binding of fatty acids. Significantly, peaks corresponding to two fatty acid-binding proteins of 32 and 45 kDa present in age-matched controls are absent from lymphocytes of patients with BCD. The 32-kDa fatty acid-binding protein present in normal individuals but absent from patients with BCD was isolated from cultured control human lymphocytes, its fatty acid-binding properties were characterized, and its amino acid composition was analyzed. It shows specific binding of 3n-3 fatty acids, consistent with the pattern of abnormalities of lipid metabolism demonstrated in patients with BCD. These results suggest that the 32- and 43-kDa FABPs are reasonable candidates for causing BCD.

Profiles of differential expression of circulating microRNAs in hepatitis B virus-positive small hepatocellular carcinoma

BACKGROUND

Abnormally expressed circulating microRNA (miRNA) may serve as a potential biomarker for the diagnosis of cancer patients.

OBJECTIVE

We sought to determine the differentially expressed circulating microRNAs in patients with hepatitis B virus (HBV)-positive small hepatocellular carcinoma (HCC) compared to other HBV-positive benign liver diseases.

METHODS

The miScript miRNA PCR Array was used to detect the levels of 84 miRNAs in plasma or serum samples of patients with HBV-related small HCC (23 cases), liver cirrhosis (LC) (20 cases), chronic hepatitis B (CHB) (20 cases) and healthy controls (16 cases). MiRNAs with fold-change values ⩾ 2 or ⩽ 0.5 compared to healthy controls were considered to be deregulated miRNAs.

RESULTS

The results of duplicate plasma experiments were not reliable. Comprehensive analysis of the two serum experiments showed that the quality controls all met the requirements. We found 18 differentially expressed miRNAs. Relative to healthy controls, nine, three, and 11 miRNAs were up-regulated in the CHB group, LC group and small HCC group, respectively. In contrast, one, three, and three miRNAs were down-regulated in the same patient groups, respectively. Interestingly, miR-195, miR-25 and miR-16 were up-regulated, and miR-205 was down-regulated, in all three experimental groups. Moreover, only in the HCC group, miR-18a, miR-100, miR-145 and miR-223 were up-regulated 3.48-, 2.95-, 2.12- and 3.91-fold, respectively, and miR-200a and miR-222 were down-regulated 2.56- and 2.00-fold, respectively.

CONCLUSIONS

Our study demonstrated the presence of six differentially expressed serum microRNAs in HBV-positive small HCC compared to other benign liver diseases associated with HBV.

Relation between therapy options for Graves' disease and the course of Graves' ophthalmopathy: a systematic review and meta-analysis

BACKGROUND

The relation between therapy options for Graves' disease (GD) and the course of Graves' ophthalmopathy (GO) are still controversial. Our aim was to compare the occurrence of development or worsening of GO in patients who were treated with antithyroid drugs (ATDs) or radioactive iodine (RAI) or thyroidectomy (TX).

METHODS

We conducted a comprehensive search of the Embase and PubMed database. Odds ratio (OR) was used as a measure of the effect of therapy options for GD on the risk of development or worsening of GO. The analysis was further stratified by factors that could affect the treatment effects.

RESULTS

Nine trials involving 1773 patients were included. RAI therapy showed a significant effect on the risk of development or worsening GO compared with ATD (OR 2.25; 95 % CI 1.61-3.14; P < 0.00001). Glucocorticoid prophylaxis was effective in preventing GO development or worsening (0.40; 0.23-0.68; P = 0.002); especially for patients with preexisting GO (0.41; 0.23-0.73; P = 0.002). At 3 months, showed GO to be improved in 17 TX and 21 total thyroid ablation (TTA) patients, with no significant difference between the two groups; between 6 and 12 months, TTA did show significant beneficial effect on the improvement of GO (6.02; 2.80-12.96; P < 0.00001); GO was found to be inactive in a significantly higher percentage of patients in the TTA (2.17; 1.04-4.52; P = 0.04).

CONCLUSION

Radioiodine therapy is a significant risk factor for development or worsening of GO in GD. But GO progression can be prevented by prophylactic glucocorticoids in patients with preexisting GO. Compared with TX alone, TTA induces an earlier and steadier GO improvement in patients with mild to moderate-severe and active GO. Whether this is sufficient to offer TTA to patients needs further investigation.

Evidence for viscoelastic effects in surface capillary waves of molten polymer films

The surface dynamics of supported ultrathin polystyrene films with thickness comparable to the radius of gyration were investigated by surface sensitive x-ray photon correlation spectroscopy. We show for the first time that the conventional model of capillary waves on a viscous liquid has to be modified to include the effects of a shear modulus in order to explain both static and dynamic scattering data from ultrathin molten polymer films.

Noninvasive measurement of protein concentration

At selected magnetic field strengths, protein and water proton spin-lattice relaxation rates are sensitive to the concentration of rotationally immobilized peptide nitrogen because of field dependent heteronuclear cross relaxation coupling between protein proton and nitrogen-14 spins that is carried to the water by proton homonuclear cross-relaxation. Measurement of the water proton spin-lattice relaxation time, or a signal amplitude proportional to it, may provide a noninvasive measure of peptide bond concentration, which provides a direct measure of immobilized protein content in most tissues. The approach using protein gels in two magnetic field strengths is demonstrated. At 66.7 mT; the proton Zeeman energy matches one of the peptide nitrogen transitions dominated by the unaveraged nuclear electric quadrupole interaction; cross-relaxation between the protons and nitrogen-14 is efficient. At 77.5 mT, the proton Zeeman energy is not matched with the nitrogen energy and proton-nitrogen cross-relaxation is not efficient. It is shown that the difference in the water proton spin-lattice relaxation rates on and off the energy level match condition is a linear function of the rotationally immobilized protein concentration.

Consistent striatal damage in rats induced by 3-nitropropionic acid and cultures of arthrinium fungus

Arthrinium fungi were cultivated from the samples of mildewed sugarcane which caused acute encephalopathy and delayed dystonia in children. The Arthrinium cultures (AC) contained 5 mg/ml 3-nitropropionic acid (3-NPA) after being inactivated and concentrated. A neuropathological study was carried out in rats intoxicated with 3-NPA and AC, respectively. Consistent bilateral striatal necrosis was found in rats with both poisonings, and the severity was well correlated with persistent recumbency which was a clinical indicator of the development of morphological brain lesions. A reproducible animal model of striatal damage has been produced in rats by IP injections of 10 mg/kg 3-NPA, 6 times a day, with an interval of 1.5 h for 3-5 days. The clinical and neuropathological manifestations in rats dosed with AC were nearly the same as those dosed with 3-NPA. The striatal lesions induced by 3-NPA and AC in poisoned rats were in accordance with the bilateral lenticular hypodensity found by CT scanning in patients of mildewed sugarcane poisoning with delayed dystonia. This neuropathological evidence supports previous epidemiological and mycological findings which indicate that 3-NPA is the possible pathogen of acute mildewed sugarcane poisoning.

3-Nitropropionic acid produces indirect excitotoxic damage to rat striatum

The mechanism of striatal damage induced by 3-nitropropionic acid (3-NPA) was studied in rats by neuropathological and neurochemical methods. Neuronal shrinkage with astrogliosis was observed in striatum after local injection of 0.5-5 mumol 3-NPA. Decortications involving dorsal and lateral aspects of frontal cortex or both frontal and parietal cortices significantly decreased the severity of striatal injuries induced by 3-NPA. This result suggests that corticostriatal projections play an important role in the development of striatal damage. No significant increase of glutamate and aspartate in striatal dialysates was observed, which indicated that 3-NPA may affect the postsynaptical sites and make the striatal neurons more vulnerable to endogenous levels of glutamate. Both of these findings suggested that 3-NPA produces indirect excitotoxic lesion to striatum. An increase of dopamine found in striatal dialysates may also be related to the occurrence of striatal damage.

Thickness induced structural changes in polystyrene films

Changes to the structure of polystyrene melt films as measured through the spectrum of density fluctuations have been observed as a function of film thickness down to the polymer radius of gyration (Rg). Films thicker than 4Rg show bulklike density fluctuations. Thinner films exhibit a peak in S(q) near q=0 which grows with decreasing thickness. This peak is attributed to a decreased interpenetration of chains resulting in an enhanced compressibility. Measurements were made using small angle x-ray scattering in a standing wave geometry designed to enhance scattering from the interior of the film compared to interface scattering.

The value of cervical mediastinoscopy combined with anterior mediastinotomy in the peroperative evaluation of bronchogenic carcinoma of the left upper lobe

METHODS

From January 1990 to July 1994, 85 patients who were otherwise thought to have an operable tumour within the left upper lobe underwent left anterior mediastinotomy supplemented by cervical mediastinoscopy in 75 cases. This combined approach allowed assessment of nodal involvement within the superior and anterior mediastinal areas, the detection of direct tumour invasion into the mediastinum and the determination of resectability by bidigital examination of the area around the aortic arch and sub-aortic fossa.

RESULTS

It was found that 27 (31.8%) patients were inoperable, either because of nodal involvement at cervical mediastinoscopy (4 patients) or because of extension into the mediastinum at left anterior mediastinotomy (14 patients), or because of positive results from both methods (9 patients). The inoperability determined by this examination for patients with adenocarcinoma (8/18, 44.4%) is higher than for patients with squamous carcinoma (12/52, 23.1%). All of the 58 patients with negative findings proceeded to thoracotomy and complete resection was possible in 54 patients (93.1%).

CONCLUSION

We conclude that this combined approach is better than using either technique alone in the preoperative staging and the evaluation of resectability of left upper lobe tumours.

First Report of Ilyonectria robusta Causing Rusty Root of Asian Ginseng in China

Asian ginseng (Panax ginseng) is an economically important perennial herb, mainly cultivated in Jilin Province, China. In September 2013, Asian ginseng plants in Jilin showed rusty root symptoms. Typical symptoms included rusty superficial lesions of irregular shapes and margins. Ten symptomatic roots were collected from each of five fields for investigation. To isolate the pathogen, root epidermal tissues with typical lesions were excised, surface-sterilized, and placed on potato dextrose agar (PDA) amended with 50 μg/ml tetracycline. After incubation at 20 ± 1°C in the dark for a week, 18 single-spore isolates out of 50 samples were obtained and identified as Ilyonectria robusta (A.A. Hildebr.) A. Cabral & Crous based on morphological characters and DNA sequence analysis (1). After incubating 7 days on PDA in the dark at 20°C, colonies were cottony to felty in texture and orange white to brownish grey in color with average diameters of 60 ± 3 mm. Isolates were cultured on synthetic nutrient-poor agar for conidial measurements. Macroconidia formed on simple conidiophores predominately, with mostly one and occasionally up to three septa, and were cylindrical with both ends broadly rounded. Macroconidia varied in size depending on the number of cells as follows: one-septate, 7.0 ± 0.6 × 27.7 ± 2.7 μm; two-septate, 7.3 ± 0.7 × 33.3 ± 2.1 μm; three-septate, 7.4 ± 0.6 × 33.4 ± 2.2 μm. Microconidia that formed on complex conidiophores were ellipsoid to ovoid and ranged in size from aseptate 3.7 ± 0.5 × 8.7 ± 1.1 μm to one-septate 5.0 ± 0.6 × 13.1 ± 1.6 μm. Brown chlamydospores were abundantly produced on PDA, globose to subglobose in shape, and in size of 10.9 ± 1.3 × 11.8 ± 1.5 μm (n ≥ 30 observations per structure for each measurement). The isolates were further classified by amplifying and sequencing the ITS1-5.8S rRNA-ITS2 region and histone H3 gene with primer pairs ITS5 and ITS4 (4), and H3-1a and H3-1b (3), respectively. Sequences of the two loci (GenBank Accession Nos. KM015300 and KM015299) showed 100% identity among the three examined isolates and the published I. robusta isolates (JF735268 and JF735517). To confirm the pathogenicity, bare roots of 3-year-old Asian ginseng were inoculated with mycelial plugs of three isolates of I. robusta selected randomly. Four roots were inoculated as replicates for each isolate with pathogen-free agar plugs as a control. One week post-inoculation in the dark at 20 ± 1°C, all the inoculated ginseng roots showed light-brown to dark-brown lesions. I. robusta was recovered from symptomatic roots and confirmed by analyzing the DNA sequence of the histone H3 gene. The inoculation experiment was repeated, and both trials showed the same results. The ginseng tissue under the control agar plugs remained symptomless, and no fungi were isolated. To our knowledge, this is the first report of I. robusta causing rusty root of P. ginseng in China (1,2,5). References: (1) A. Cabral et al. Mycol. Prog. 11:655, 2012. (2) I. Erper et al. Eur. J. Plant Pathol. 136:291, 2013. (3) N. L. Glass et al. Appl. Environ. Microbiol. 61:1323, 1995. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (5) X. Lu et al. Plant Dis. 98:1580, 2014.

Pretreatment surgical lymph node staging predicts results of trimodality therapy in esophageal cancer

OBJECTIVE

Prediction of responders to induction therapy in esophageal cancer (EC) patients is important. In this study, we evaluated the role of thoracoscopic/laparoscopic (Ts/Ls) staging in prediction of treatment response and survival in EC patients with trimodality treatment.

METHODS

Retrospective study of EC patients who had undergone Ts/Ls staging and received trimodality treatment at the University of Maryland Medical Center and the Baltimore Veterans Administration Hospitals from July, 1991 to December, 1999. Preoperative therapy consisted of concurrent chemotherapy (5-FU + cisplatinum) and radiotherapy.

RESULTS

Forty-four EC patients who underwent pretreatment Ts/Ls staging during the study period were able to complete concurrent chemoradiotherapy followed by surgical resection. There were 36 men and 8 women aged 40 to 77 (median age 62). Twenty-seven (61.4%) patients were found to have lymph node metastasis by surgical staging. Fourteen patients (31.8%) had a pathologic complete response. Patients with positive lymph nodes had a lower response rate than those with negative lymph nodes (14.8% vs. 58.8%, P=0.006). Other clinicopathologic features including gender, weight loss, clinical TNM stage, surgical T stage, and histology did not correlate with treatment response. Univariate analysis showed that weight loss and treatment response were important prognostic factors for disease-free survival (P=0.01 and P=0.02, respectively). Histology, surgical N stage and surgical TNM stage appeared to be associated with prognosis (P=0.067-0.097). Multivariate analysis revealed that only surgical N status and weight loss were significant prognostic factors (P=0.05, and P=0.006, respectively).

CONCLUSIONS

Surgical Ts/Ls staging provides accurate evaluation of tumor spread in EC patients. Pretreatment N status was the single most important predictor of response to induction treatment as well as a reliable prognosticator of survival.

Pericardial repair after extensive resection: another use for the pedicled diaphragmatic flap

BACKGROUND

Extended resection for pulmonary malignancy frequently leaves a large pericardial defect, sometimes associated with resection of the phrenic nerve. On the left the defect does not require repair; as long as the defect is sufficiently large to avoid constriction, the heart can herniate freely. On the right such herniation is associated with venous inflow occlusion and death. The pedicled diaphragmatic flap has been used in other situations in thoracic surgery. We have modified this to allow closure of the pericardial defect and concurrent plication of the denervated diaphragm. It may also be used to cover the bronchial stump or a bronchial anastomosis.

METHODS

The flap has been used in 13 patients over an 11-year period.

RESULTS

Secure closure of the pericardial defect has been achieved in all patients with satisfactory plication of the diaphragm. Reoperation for bleeding was necessary in 3 patients, but in only 1 was the diaphragm shown to be the site of bleeding. Patients otherwise made an uneventful recovery.

CONCLUSIONS

A large pedicled flap of redundant diaphragm provides secure closure for large pericardial defects after extended right pneumonectomy.

Thoracoscopic and laparoscopic staging for esophageal cancer

Accurate pretreatment staging for patients with esophageal cancer (EC) is becoming increasingly important in the evaluation and comparison of different treatment modalities. Noninvasive staging methods are imperfect in detecting lymph node metastasis in patients with EC. Surgical staging with the thoracoscopic/laparoscopic (Ts/Ls) technique may provide accurate staging information that is useful for evaluating and comparing the results of clinical trials of preoperative chemotherapy and radiotherapy. It can be used to confirm or exclude suspicious distant metastasis found by other staging methods. Pretreatment (lymph node) biopsies obtained by Ts/Ls staging allow further molecular biologic analysis to detect occult lymph node metastasis for more accurate lymph node staging. Since 1992, we have used Ts/Ls staging for EC in 111 patients. We found that Ts/Ls is a promising method for staging lymph nodes in EC patients. A recent study showed that pretreatment surgical lymph node staging can predict response and survival for EC patients receiving trimodality treatment (ie, radiation, chemotherapy, and surgery). The information obtained with surgical staging now offers us the opportunity to optimize therapy to specific patient groups based on the extent of disease at the time of initial presentation. Nevertheless, unlike the practice of mediastinoscopy in lung cancer patients, Ts/Ls staging in EC patients remains an academic interest rather than a clinical practice. The concept of accurate pretreatment staging of EC remains to be realized and accepted in the clinical community.

Pleural lavage cytology in esophageal cancer without pleural effusions: clinicopathologic analysis

OBJECTIVE

The literature of pleural lavage cytology (PLC) is focused on lung cancer. We conducted this pilot study to determine the incidence of malignant pleural cytologies in patients without pleural effusions who undergo curative resection for esophageal cancer, and to evaluate the clinicopathologic significance of positive cytology.

METHODS

Forty-eight patients underwent esophagectomy for thoracic esophageal cancer in our unit from January 1998 to January 1999. After thoracotomy, pleural lavage was performed before any intrathoracic manipulation and cytologically evaluated.

RESULTS

There was one patient with stage I, 27 patients with stage II, and 20 patients with stage III cancer of the thoracic esophagus. The mean age was 55 years (range 41-77 years). Fifteen cases (31.3%) were found to have positive lymph nodes (N1). Squamous cell carcinoma was the dominant histopathologic type (91.7%). Positive lavage cytology in the whole group was found in 18.8% (9/48). There was no significant correlation to gender, age, clinical symptoms, histology, T or N status, TNM stage, or tumor location.

CONCLUSIONS

The incidence of positive pleural lavage cytology in esophageal cancer is disconcertingly high. Positive cytology might suggest a more aggressive tumor biology. Future studies on its relation to survival and occult lymphatic metastasis are warranted.

Immunohistochemical localization of interleukin-2 and its receptor subunits alpha, beta and gamma in the main olfactory bulb of the rat

Endogenous interleukin-2 (IL-2) was found in the adult rat brain, however, it has not been reported whether this cytokine is present in the olfactory bulb. Immunohistochemical techniques were used to examine the cellular localization of IL-2 and its receptor subunits in the main olfactory bulb of the rat. Strong IL-2 immunoreactivity was localized in glial cells, specifically in the olfactory nerve layer, glomerular layer and external plexiform layer. IL-2 mRNA was detected in the olfactory bulb by RT-PCR. All three IL-2 receptor subunits also showed distinct laminar distributions. The IL-2Ralpha and IL-2Rbeta immunoreactivity was found both in neurons and glial cells, whereas IL-2Rgamma imunoreactivity was found in glial cells, and thus resembled IL-2 immunostaining. The present results demonstrated a wide distribution of IL-2 and its receptor subunits in the main olfactory bulb of the rat, suggesting that IL-2 might play a role in the olfactory function through autocrine or paracrine pathways. The exclusive high expression of IL-2 in glial cells in distinct laminar structures, where neuron-glia interactions are closely associated with olfactory nerve regeneration, imply that IL-2 might be involved in the process of nerve regeneration in the olfactory bulb.

Measurement of annexin V uptake and lactadherin labeling for the quantification of apoptosis in adherent Tca8113 and ACC-2 cells

Phosphatidylserine (PS) exposure occurs during the cell death program and fluorescein-labeled lactadherin permits the detection of PS exposure earlier than annexin V in suspended cell lines. Adherent cell lines were studied for this apoptosis-associated phenomenon to determine if PS probing methods are reliable because specific membrane damage may occur during harvesting. Apoptosis was induced in the human tongue squamous carcinoma cell line (Tca8113) and the adenoid cystic carcinoma cell line (ACC-2) by arsenic trioxide. Cells were harvested with a modified procedure and labeled with lactadherin and/or annexin V. PS exposure was localized by confocal microscopy and apoptosis was quantified by flow cytometry. The detachment procedure without trypsinization did not induce cell damage. In competition binding experiments, phospholipid vesicles competed for more than 95 and 90% of lactadherin but only about 75 and 70% of annexin V binding to Tca8113 and ACC-2 cells. These data indicate that PS exposure occurs in three stages during the cell death program and that fluorescein-labeled lactadherin permitted the detection of early PS exposure. A similar pattern of PS exposure has been observed in two malignant cell lines with different adherence, suggesting that this pattern of PS exposure is common in adherent cells. Both lactadherin and annexin V could be used in adherent Tca8113 and ACC-2 cell lines when an appropriate harvesting procedure was used. Lactadherin is more sensitive than annexin V for the detection of PS exposure as the physical structure of PS in these blebs and condensed apoptotic cell surface may be more conducive to binding lactadherin than annexin V.

The effect of mannitol and anisodamin on the prevention of free radical injury to post-ischaemia flaps: an experimental study

Rat abdominal skin flaps were subjected to total venous occlusion for 8 h. Five minutes before release of the vascular occlusion, mannitol, mannitol plus anisodamin, anisodamin or placebo (0.9% normal saline) was administered intravenously. Drug treated flaps showed a statistically significant increase in the proportion of area surviving (P < 0.001). The combination of mannitol and anisodamin was not more effective than either agent alone in increasing the proportion of area surviving. The results of biochemical analyses indicated that neither mannitol nor anisodamin affected xanthine oxidase activity (p > 0.05) but that both agents significantly reduced the increase of malondialdehyde (MDA) concentration caused by ischaemia-reperfusion (p < 0.01). Treatment with mannitol or anisodamin also prevented the increase of lactate and water content and the decrease in glucose content in the island skin flap tissue which occurred on reperfusion. The data indicate that mannitol and/or anisodamin have the potential to salvage anticipated flap necrosis. It is possible that the mechanism of action is inhibition of damage caused by toxic oxygen species and improvement in capillary reperfusion.

The accuracy of bone mineral density measurement using dual-energy spectral CT and quantitative CT: a comparative phantom study

AIM

To compare bone mineral density (BMD) measurement accuracy by dual-energy spectral computed tomography (CT) and quantitative CT (QCT) using an anthropomorphic European spine phantom (ESP).

MATERIALS AND METHODS

An ESP containing three hydroxyapatite inserts with densities of 50, 100, and 200 mg/cm³ was scanned 10 times each using spectral CT and QCT protocols. Their BMD values were measured using hydroxyapatite-based spectral CT material decomposition images and QCT images and compared with the true values in ESP.

RESULTS

Both protocols had good repeatability in BMD measurement with low coefficient-of-variance (spectral CT: <2.31%; QCT: <1.17%). There were biases in BMD measurement for the 50, 100, and 200 mg/cm³ hydroxyapatite insert with relative errors of 2.34% (48.83±1.13 mg/cm³), 2% (98±1.25 mg/cm³) and 5.96% (188.09±2.11 mg/cm³), in spectral CT, and 11% (55.5±0.65 mg/cm³), 9.85% (109.85±0.42 mg/cm³) and 4.04% (208.07±0.54 mg/cm³) in QCT, respectively.

CONCLUSION

BMD can be accurately measured using either QCT or spectral CT, and spectral CT has smaller bias than QCT.

The MTHFR C677T mutation is not a risk factor recognized for HBV-related HCC in a population with a high prevalence of this genetic marker

BACKGROUND

Polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene can affect disease progression in HBV infection. However, the results from different reports are inconsistent. The aim of this study was to investigate the association between the MTHFR C677T polymorphism and the outcome of HBV infection in a Tianjin Han population.

METHODS

TaqMan SNP genotyping was employed to determine the alleles and genotypes of MTHFR C677T in 2511 subjects from various stages of HBV infection and 549 healthy controls.

RESULTS

Of the 3060 subjects, the genotypic frequencies were CT 48.9%, TT 29.3% and CC 21.8%; the allelic frequencies were T 53.8% and C 46.2%. There was no significant difference in genotypic or allelic distribution among the different disease groups. When either healthy subjects or self-limited subjects were used as controls, the TT genotype and the T allele conferred protective effects against hepatocellular carcinoma (HCC) (HCC vs healthy subjects: OR=0.588, 95% CI=0.413-0.836, P=0.003; OR=0.768, 95% CI=0.645-0.915, P=0.003, respectively. HCC vs self-limited subjects: OR=0.598, 95% CI=0.404-0.886, P=0.010; OR=0.772, 95% CI=0.635-0.940, P=0.010, respectively). After sub-stratification by gender, the prevalence of the TT genotype or T allele was the lowest in the male HCC group (TT 23.5%, T 49.8%). The protective effects of the TT genotype and the T allele were observed in male HCC and cirrhotic subjects (HCC vs self-limited subjects: OR=0.470, 95% CI=0.288-0.766, P=0.002; OR=0.681, 95% CI=0.535-0.866, P=0.002, respectively. Liver cirrhosis vs self-limited subjects: OR=0.624, 95% CI=0.392-0.992, P=0.046; OR=0.791, 95% CI=0.627-0.998, P=0.048, respectively), but not in female. When the subjects were stratified according to the clinical features, no statistically significant difference in the genotypic distribution was observed (P>0.05).

CONCLUSIONS

The TT genotype and T allele of MTHFR C677T may confer a protective effect on disease progression to HCC in HBV-infected individuals, especially among male patients, in a population with a high prevalence of this genetic marker.