Herbivore-Dependent Induced Volatiles in Pear Plants Cause Differential Attractive Response by Lacewing Larvae.

Biological control may benefit from the behavioral manipulation of natural enemies using volatile organic compounds (VOCs). Among these, herbivore-induced plant volatiles (HIPVs) provide potential tools for attracting or retaining predators and parasitoids of insect pests. This work aimed to characterize the VOCs emitted by pear plants in response to attack by Cacopsylla bidens (Hemiptera: Psyllidae), a major pest in pear orchards, to compare these with VOCs induced by a leaf chewing insect, Argyrotaenia sphaleropa (Lepidoptera: Tortricidae), and to evaluate the behavioral response of Chrysoperla externa (Neuroptera: Chrysopidae) to HIPVs from pear plants damaged by either herbivore. The results demonstrated that plants damaged by the pear psylla emitted VOC blends with increased amounts of aliphatic aldehydes. Leafroller damage resulted in increased amounts of benzeneacetonitrile, (E)-4,8-dimethylnona-1,3,7-triene, ß-ocimene and caryophyllene. In olfactometer bioassays, larvae of C. externa were attracted to herbivore-damaged plants when contrasted with undamaged plants. When plant odors from psylla-damaged were contrasted with those of leafroller-damaged plants, C.externa preferred the former, also showing shorter response lag-times and higher response rates when psylla-damaged plants were present. Our results suggest that pear plants respond to herbivory by modifying their volatile profile, and that psylla-induced volatiles may be used as prey-specific chemical cues by chrysopid larvae. Our study is the first to report HIPVs in pear plants attacked by C. bidens, as well as the attraction of C. externa to psyllid-induced volatiles.

The contribution of intermolecular spin interactions to the London dispersion forces between chiral molecules.

Dispersion interactions are one of the components of van der Waals (vdW) forces that play a key role in the understanding of intermolecular interactions in many physical, chemical, and biological processes. The theory of dispersion forces was developed by London in the early years of quantum mechanics. However, it was only in the 1960s that it was recognized that for molecules lacking an inversion center, such as chiral and helical molecules, there are chirality-sensitive corrections to the dispersion forces proportional to the rotatory power known from the theory of circular dichroism and with the same distance scaling law R-6 as the London energy. The discovery of the chirality-induced spin selectivity effect in recent years has led to an additional twist in the study of chiral molecular systems, showing a close relation between spin and molecular geometry. Motivated by it, we propose in this investigation to describe the mutual induction of charge and spin-density fluctuations in a pair A-B of chiral molecules by a simple physical model. The model assumes that the same fluctuating electric fields responsible for vdW forces can induce a magnetic response via a Rashba-like term so that a spin-orbit field acting on molecule B is generated by the electric field arising from charge density fluctuations in molecule A (and vice versa). Within a second-order perturbative approach, these contributions manifest as an effective intermolecular exchange interaction. Although expected to be weaker than the standard London forces, these interactions display the same R-6 distance scaling.

Intrinsic Rashba coupling due to hydrogen bonding in DNA.

We present an analytical model for the role of hydrogen bonding on the spin-orbit coupling of a model DNA molecule. Here, we analyze in detail the electric fields due to the polarization of the hydrogen bond on the DNA base pairs and derive, within a tight binding analytical band folding approach, an intrinsic Rashba coupling which should dictate the order of the spin active effects in the chiral-induced spin selectivity effect. The coupling found is ten times larger than the intrinsic coupling estimated previously and points out to the predominant role of hydrogen bonding in addition to chirality in the case of biological molecules. We expect similar dominant effects in oligopeptides, where the chiral structure is supported by hydrogen-bonding and bears on orbital carrying transport electrons.

Enantiospecificity in NMR enabled by chirality-induced spin selectivity.

Spin polarization in chiral molecules is a magnetic molecular response associated with electron transport and enantioselective bond polarization that occurs even in the absence of an external magnetic field. An unexpected finding by Santos and co-workers reported enantiospecific NMR responses in solid-state cross-polarization (CP) experiments, suggesting a possible additional contribution to the indirect nuclear spin-spin coupling in chiral molecules induced by bond polarization in the presence of spin-orbit coupling. Herein we provide a theoretical treatment for this phenomenon, presenting an effective spin-Hamiltonian for helical molecules like DNA and density functional theory (DFT) results on amino acids that confirm the dependence of J-couplings on the choice of enantiomer. The connection between nuclear spin dynamics and chirality could offer insights for molecular sensing and quantum information sciences. These results establish NMR as a potential tool for chiral discrimination without external agents.

A stochastic surrogate Hamiltonian approach of coherent and incoherent exciton transport in the Fenna-Matthews-Olson complex.

The capture and transduction of energy in biological systems is clearly necessary for life, and nature has evolved remarkable macromolecular entities to serve these purposes. The Fenna-Matthews-Olson (FMO) complex serves as an intermediate to transfer the energy from the chlorosome to the special pairs of different photo systems. Recent observations have both suggested the importance of coherent exciton transport within the FMO and motivated an elegant and appropriate theoretical construct for interpreting these observations. Here we employ a different approach to exciton transport in a relaxing environment, one based on the stochastic surrogate Hamiltonian method. With it, we calculate the quantum trajectories through the FMO complex both for the model involving seven bacteriochlorophylls that has been used before, and for one involving an eighth bacteriochlorophyll, which has been observed in some new and very important structural work. We find that in both systems, efficient energy transfer to the ultimate receptor occurs, but that because of the placement of, and energy relaxation among, the different bacteriochlorophyll subunits in the FMO complex, the importance of coherent oscillation that was discussed extensively for the seven site system is far less striking for the eight site system, effectively because of the weak mixing between the initial site and the remainder of the system. We suggest that the relevant spectral densities can be determinative for the energy transport route and may provide a new way to enhance energy transfer in artificial devices.

Acute pancreatitis secondary to pancreatic carcinoma. Study Group Participants.

Acute pancreatitis (AP) has been recognized as a presentation of patients with pancreatic carcinoma (PC). However, the natural history of patients with PC who present with AP as the first manifestation is largely unknown. The aim of this study was to determine the time between the presentation of AP and diagnosis of PC and what factors should alert the clinician to suspect underlying PC in patients with AP. Nineteen physicians completed the survey forms that encompassed 45 patients with a diagnosis of AP preceding a diagnosis of PC. Information included the patient's age, gender, race, conditions that could account for the AP, criteria for diagnosis of AP, severity of AP, criteria for diagnosis of PC, time between the diagnosis of AP and PC, pathology of the carcinoma, extension of the disease, treatment of PC, and survival after the diagnosis of PC. The study population consisted of 45 patients, 27 (60%) men and 18 (40%) women whose average age was 58 years (range, 32-89). Thirty-eight patients were Caucasian, five were black, one was Japanese, and one Arabian. The number of AP episodes before PC diagnosis ranged between one and 15 (mean + 2 SD). AP was mild in 40 (89%) and severe in five (11%). The time between the onset of AP and the diagnosis of PC averaged 34 weeks (range, 1-52). Symptoms on presentation of AP included abdominal pain 45 (100%), weight loss 15 (33%), and jaundice 3 (7%). CA 19-9 was available in 13 patients, eight of whom had levels >100 at the time AP was diagnosed. Abnormal imaging suggestive of PC was detected by ultrasonography in 17 patients, by computed tomography in 30, endoscopic retrograde cholangiopancreatography in 20, and endoscopic ultrasonography in three. Tissue diagnosis was obtained in 43 of 45 (96%) patients; by surgery in 25 patients, needle aspiration in 14, laparoscopy in one, autopsy in two, and lymph node in one. Pathology revealed adenocarcinoma in 37 patients, squamous cell carcinoma in two, undifferentiated carcinoma in two, islet cell in one, and cystadenocarcinoma in one. Surgical findings in 26 patients included 19 with a nonresectable lesion or metastasis and seven patients with resectable lesion for cure. Thirteen patients (28%) were alive 1 year after the diagnosis of PC. The patients had a mean of two (range, one to 15) episodes of AP before the diagnosis of PC, and this was associated with a delay of 34 weeks from AP to diagnosis of PC. Patients with PC who presented with AP were generally older than 50 years of age and the severity of the pancreatitis was mild. The survival rate of patients with PC who presented initially with AP was >25% at 1 year compared with 20% 1 year overall survival of patients with PC. AP seems to be an early presentation of PC and should be sought in patients with idiopathic pancreatitis.

Occult gastrointestinal bleeding. General overview and approach.

Occult gastrointestinal bleeding is most commonly defined as an acute or chronic loss of blood, the source of which has not been identified after gastroscopy, colonoscopy, and upper gastrointestinal series have been performed. As the title suggests, this article provides a general overview of this disorder. Specific topics discussed include etiology, diagnostic procedures, laboratory studies, radiologic procedures, radionuclide studies, angiography, and endoscopy.

Recognizing atypical manifestations of GERD. Asthma, chest pain, and otolaryngologic disorders may be due to reflux.

The presence of common symptoms, such as heartburn and regurgitation, usually make the diagnosis of gastroesophageal reflux disease (GERD) fairly straightforward. However, extraesophageal symptoms of GERD, such as asthma, noncardiac chest pain, and hoarseness, are often not recognized and therefore are poorly managed. This article sheds light on the atypical manifestations of GERD as well as current approaches to diagnosis and treatment.

When it's hard to swallow. What to look for in patients with dysphagia.

Swallowing disorders can be divided into oropharyngeal dysphagia and esophageal dysphagia. The most common cause of oropharyngeal dysphagia is cerebrovascular accidents; other causes may include oropharyngeal structural lesions, systematic and local muscular diseases, and diverse neurologic disorders. Esophageal dysphagia may result from neuromuscular disorders, mortality abnormalities, and intrinsic or extrinsic obstructive lesions. Through clinical history taking helps define the tpe of dysphagia and can guide diagnostic testing. Important questions to ask patients with the disorder include specific features of the dysphagia, its onset and progression, accompanying problems, and eating habits adopted to relieve symptoms. Videofluoroscopy should be the initial test in evaluating oropharyngeal dysphagia. Barium-contrast esophagography identifies most anatomic causes of dysphagia and some motor disorders and is better tha endoscopy at identifying extrinsic esophageal compression and intramural lesions not involving the esophageal mucosa. Cine-esophagography may provide clues to a possible esophageal motor disorder causing dysphagia. Endoscopy is the test of choice if obstruction or gastroesophageal reflux disease is suspected, because biopsies can confirm the presence of esophagitis and provide specific pathologic identification of the obstructive lesion. In addition, therapeutic dilatation of a stricture and removal of foreign bodies can be accomplished as part of the evaluation procedure. When no obvious source of dysphagia is apparent after radiologic and endoscopic assessment, manometry for possible motility disorder should be considered.

Subjects with impaired fasting glucose: evolution in a period of 6 years.

AIM: To study the evolution of impaired fasting glucose (IFG), considering glucose and HbA1c levels and risk factors associated, in a period of 6 years. METHODS: We studied 94 subjects with impaired fasting glucose (IFG) that were diagnosed in 2005 and followed up to 2012. Glucose and HbA1c levels were determined. A descriptive analysis of contingence charts was performed in order to study the evolution in the development of type-2 diabetes mellitus (T2DM). RESULTS: Twenty-eight of ninety-four subjects became T2DM; 51/94 remained with IFG; and 20/94 presented normal fasting glucose. From the 28 diabetic subjects, 9 had already developed diabetes and were under treatment with oral hypoglycemic agents; 5 were diagnosed with plasma glucose < 126 mg/dL, but with HbA1c over 6.5%. In those who developed diabetes, 15/28 had a family history of T2DM in first relative degree. Also, diabetic subjects had a BMI significantly higher than nodiabetics (t test: P < 0.01). The individuals that in 2005 had the highest BMI are those who currently have diabetes. CONCLUSION: The IFG constitutes a condition of high risk of developing T2DM in a few years, especially over 110 mg/dL and in obesity patients.

High-sensitivity C-reactive protein and liver enzymes in individuals with Metabolic Syndrome in Talca, Chile.

Metabolic syndrome (MS) is a core set of disorders, including abdominal obesity, dyslipidemia, hypertension and hypertriglyceridemia that together predict the development of diabetes type 2 and cardiovascular disease. This study investigated the relationship between liver enzyme levels and high-sensitivity C-reactive protein (hs-CRP) in subjects with and without MS. Alanine-aminotransferase (ALAT), aspartate-aminotransferase (ASAT), γ-glutamyl transferase (GGT) and hs-CRP were measured in 510 subjects, aged 40 to 65 years old. Patients were selected from 1007 subjects from the Research Program for Cardiovascular Disease Risk Factors in Talca, Chile. Results showed that women with MS presented higher liver enzyme levels than those who did not have MS. This was not observed in male patients for the enzymes ALAT and ASAT. However, GGT and hs-PCR levels were higher in male and female patients with MS than in those without MS. In conclusion, it is important to search for the presence of MS when diagnosing fatty liver. Moreover, the presence of liver disease in patients with MS should be further investigated.

Current and noise in a model of an alternating current scanning tunneling microscope molecule-metal junction.

The transport properties of a simple model for a finite level structure (a molecule or a dot) connected to metal electrodes in an alternating current scanning tunneling microscope (ac-STM) configuration is studied. The finite level structure is assumed to have strong binding properties with the metallic substrate, and the bias between the STM tip and the hybrid metal-molecule interface has both an ac and a dc component. The finite frequency current response and the zero-frequency photoassisted shot noise are computed using the Keldysh technique, and examples for a single-site molecule (a quantum dot) and for a two-site molecule are examined. The model may be useful for the interpretation of recent experiments using an ac-STM for the study of both conducting and insulating surfaces, where the third harmonic component of the current is measured. The zero-frequency photoassisted shot noise serves as a useful diagnosis for analyzing the energy level structure of the molecule. The present work motivates the need for further analysis of current fluctuations in electronic molecular transport.

[Double sphincterostomy of pancreatic and choledochal sphincters in the treatment of chronic recurrent pancreatitis]. / La esfinterotomía doble del esfínter pancreático y coledociano en el tratamiento de la pancreatitis crónica recidivante.

The treatment of recurrent chronic pancreatitis is controversial. Some patients may have sphincter of Oddi motor abnormalities. Although widely used in the biliary tree, little data is available on endoscopic sphincterotomy of the pancreatic sphincter. This report describes 5 patients with recurrent chronic pancreatitis, who had pancreatic sphincterotomy for hypertensive sphincter of Oddi. Four patients continue long-term follow-up with marked reduction of chronic pain of attacks of recurrent pancreatitis. It is concluded that endoscopic sphincterotomy of the pancreatic sphincter may improve pain in chronic pancreatitis and may obviate the need for surgery.

Pathophysiology of chest pain in patients with nutcracker esophagus.

OBJECTIVES: Nutcracker esophagus is a manometric pattern that is commonly seen in patients with functional (noncardiac) chest pain. However, this pattern is often unassociated with pain. Consequently, the pathophysiology of chest pain in these patients is unclear. METHODS: We prospectively examined the sensory perception and biomechanical properties of the esophagus in 10 patients with chest pain and a nutcracker esophagus, along with those properties in 12 healthy controls using impedance planimetry. RESULTS: Stepwise balloon distentions reproduced typical chest pain in 9/10 (90%) patients. The threshold for chest pain was lower (p < 0.05) in patients than in controls (mean +/- SD 43+/-5 vs 62+/-4 cm H2O) but only 2/12 controls experienced pain. The thresholds for first perception and moderate discomfort were also lower (18+/-8 vs 30+/-11 cm H2O, p < 0.01 and 28+/-9 vs 62+/-5 cm H2O, p < 0.001) in patients than in controls, but only 3/12 controls experienced moderate discomfort. The esophageal reactivity to balloon distention was higher in patients than in controls (p < 0.001). The tension-strain curve shifted to the left in the patient group when compared to that in the controls (p < 0.05). CONCLUSIONS: Patients with a nutcracker esophagus demonstrate a hypersensitive and stiff esophagus. Because balloon distention reproduced their chest pain, visceral hyperalgesia of the esophagus may be relevant to the pathogenesis of their pain. Balloon distention test may be more useful in the evaluation of patients with functional chest pain and a nutcracker esophagus.

[Asymptomatic Addison disease: cause of striking reduction of insulin requirements in a patient with diabetes, Hashimoto thyroiditis and Basedow disease]. / Addison inaparente: causa de drástica reducción del requerimiento de insulina en una paciente con diabetes, tiroiditis de Hashimoto y enfermedad de Basedow.

We report a 30 years old woman with sporadic poliglandular autoimmune syndrome type II, first seen with an insulin-dependent diabetes mellitus and a Graves-Basedow disease that became spontaneously hypothyroid with positive antimicrosomal antibodies. Six years later she presented with persistent vomiting and a remarkable reduction in insulin requirements. She had low basal and stimulated-cortisol levels and the diagnosis of severe adrenal failure was reached. A CT scan showed normal adrenal glands, she did not have cutaneous hyperpigmentation nor evidences of mineralocorticoid deficit. A selective autoimmune damage of the fascicular zone was assumed but a selective damage of ACTH producing pituitary cells cannot be discarded. The importance of investigating adrenal function in cases of unexplained reduction of insulin requirements is emphasized.

The effect of transcutaneous nerve stimulation on sphincter of Oddi pressure in patients with biliary dyskinesia.

Vasoactive intestinal polypeptide (VIP) has been postulated as a neuropeptide with inhibitory neurotransmitter activity in nonadrenergic noncholinergic pathways. Transcutaneous electric nerve stimulation (TENS) relaxes the lower esophageal sphincter in patients with achalasia. Such response is accompanied by a 30% increase in VIP concentrations in the systemic circulation. Since the sphincter of Oddi (SO) receives a very dense VIP nerve supply, we evaluate the effect of TENS on SO motor activity and on VIP plasma concentrations in patients with biliary dyskinesia and in healthy volunteers. TENS was performed with a pocket stimulator for 45 min. SO pressure and VIP levels were obtained before and after 45 min of TENS. In patients with SO dyskinesia, TENS produced a significant decrease in SO pressure from 80.1 +/- 11.9 mm Hg to 58.3 +/- 9.7 mm Hg p less than 0.01); this was accompanied by a significant increase in VIP plasma levels from 21.1 +/- 0.5 pg/ml to 32.6 +/- 1.5 pg/ml (p less than 0.01). In healthy volunteers, TENS did not produce significant changes in SO pressure. However, a significant increase in VIP plasma values was observed (p less than 0.01). No significant changes in amplitude, duration and frequency of SO phasic contractions were observed in either of the two groups evaluated. We conclude that, in patients with SO dyskinesia, TENS decreases SO basal pressure, possibly by a direct action of the released VIP in the systemic circulation. In healthy volunteers, TENS increases VIP plasma values without significant effect on SO basal pressure. These findings suggest that the response to TENS may be mediated by VIP. It is also possible that the alterations seen in patients with biliary dyskinesia may be due to impairment of the VIP nerve supply at the level of the SO.

The effect of vasoactive intestinal polypeptide on the lower esophageal sphincter in achalasia.

Vasoactive intestinal polypeptide (VIP) is one of the main neurotransmitters implicated in the relaxation of the lower esophageal sphincter (LES). The effect of exogenous VIP on LES motor activity was determined by esophageal manometry. LES pressure (LESP) and LES relaxation were compared in four healthy volunteers and in six patients with achalasia. The effects of intravenous doses of 1.5, 3, and 5 pmol.kg-1.min-1 of VIP were compared with placebo. Neither placebo nor 3 and 5 pmol.kg-1.min-1 of VIP produced any effect on esophageal motility in healthy volunteers. In achalasia the three doses of VIP caused a dose-dependent decrease in LESP with a significant improvement in LES relaxation. A dose of 5 pmol.kg-1.min-1 produced a maximal decrease of 51% in LESP. A beta-adrenergic agonist, isoproterenol, caused a decrease in LESP both in healthy volunteers and in patients with achalasia without improving LES relaxation. In summary, intravenous VIP improved LES relaxation and caused a decrease in LESP in patients with achalasia without affecting LESP in healthy volunteers, indicating that the LES muscle in achalasia is supersensitive to VIP. The current study suggests that a selective damage in the noncholinergic nonadrenergic innervation of the esophagus is in part responsible for the motor alteration seen in these patients. The findings and the inability of isoproterenol to improve LES relaxation despite decreasing LESP support a role in VIP as a indicator of LES relaxation.

[Clinical experience with an alpha glucosidase inhibitor (acarbose) in the treatment of non-insulin-dependent diabetes. Multicenter study]. / Experiencia clínica con un inhibidor de la alfa glucosidasa (acarbosa) en el tratamiento de la diabetes no insulinodependiente. Estudio multicéntrico.

BACKGROUND: Acarbose, an alpha glucosidase inhibitor is a drug used in the treatment of non insulin dependent diabetes mellitus, that interferes with the intestinal absorption of monosaccharides. AIM: To study the effect of acarbose in non insulin dependent diabetic patients that had an inadequate metabolic control with diet and sulphonylureas. PATIENTS AND METHODS: Diabetic patients received acarbose, 150 mg/day during four weeks and this dose was increased to 300 mg/day during 3 months. Afterwards, patients were followed for a period of 12 weeks without acarbose. Fasting and post-prandial blood glucose and glycosilated hemoglobin were measured sequentially during the study. RESULTS: Eighty five patients were recruited for the study but 64 complied with the treatment protocol. The age of these patients was 56 +/- 8.8 years old, their diabetes duration was 7.8 +/- 8.8 years and their body mass index was 27.6 +/- 3.6 kg/m2. During acarbose treatment, glycosilated hemoglobin decreased from 8.36 +/- 1.33 to 7.71+ 1.7% (p < 0.001), fasting blood glucose decreased from 173 +/- 48 to 159 +/- 59 mg/dl (p < 0.03) and post-prandial blood glucose decreased from 254 +/- 80 to 241 +/- 80 mg/dl (NS). After discontinuing acarbose glycosilated hemoglobin and blood glucose levels returned to basal levels. Body weight and blood pressure did not change during the treatment period. Fifty nine patients had gastrointestinal symptoms (meteorism, flatulence and abdominal distention) that were mild in 59% and moderate in 39%. Episodes of hypoglycemia were not observed. CONCLUSIONS: Acarbose, associated to sulphonylureas is an effective drug to reduce blood glucose and glycosilated hemoglobin levels in patients with non insulin dependent diabetes.