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, β-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.

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.

[Clinical experience with an alpha glucosidase inhibitor (acarbose) in the treatment of non-insulin-dependent diabetes. Multicenter study]

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.

[Asymptomatic Addison disease: cause of striking reduction of insulin requirements in a patient with diabetes, Hashimoto thyroiditis and Basedow disease]

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 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.

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.

[Double sphincterostomy of pancreatic and choledochal sphincters in the treatment of chronic recurrent pancreatitis]

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.