Effect of chemical structure on the subglass relaxation dynamics of biobased polyesters as revealed by dielectric spectroscopy: 2,5-furandicarboxylic acid vs. trans-1,4-cyclohexanedicarboxylic acid.

The chemical structure-dynamics relationship for poly(trimethylene 2,5-furanoate) and poly(trimethylene 1,4-cyclohexanedicarboxylate) was investigated via dielectric spectroscopy and compared with that of poly(trimethylene terephthalate) in order to evaluate the impact on the subglass dynamics of the chemical nature of the ring. Further comparison was accomplished with the neopentyl glycol containing counterparts: poly(neopentyl 2,5-furanoate) and poly(neopentyl 1,4-cyclohexanedicarboxylate). Our study reveals a multimodal nature of the subglass ß process. For the more flexible polymers (containing cyclohexane rings) three modes for the ß process were detected. The faster mode was assigned to the relaxation of the oxygen linked to the aliphatic carbon, the slower one to the link between the aliphatic ring and the ester group, and the third mode to the aliphatic ring. For stiffer polymers (containing aromatic rings), the local modes appear more coupled. This effect is more evident in the polymers with the furan ring where essentially a single ß mode can be resolved.

Susceptibility to rifaximin and other antimicrobials of bacteria isolated in patients with acute gastrointestinal infections in Southeast Mexico. / Susceptibilidad a la rifaximina y otros antimicrobianos de bacterias aisladas en pacientes con infecciones gastrointestinales agudas en el sureste de México.

INTRODUCTION: Enteropathogenic bacteria isolated in Mexico City have shown a high rate of resistance to different antibiotics, with the exception of rifaximin (RIF). RIF is a nonabsorbable antibiotic that reaches high fecal concentrations (≈ 8,000µg/g). Susceptibility to antimicrobials can vary in different geographic regions. AIM: To study the susceptibility to rifaximin and other antimicrobials of enteropathogenic bacteria isolated in patients with acute diarrhea in the southeastern region of Mexico. MATERIAL AND METHODS: A total of 614 strains of bacteria isolated from patients with acute diarrhea from 4 cities in Southeast Mexico were analyzed. An antibiogram with the following antibiotics was created: ampicillin (AMP), trimethoprim/sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), ciprofloxacin (CIP), chloramphenicol (CHL), and fosfomycin (FOS), assessed through the agar diffusion method at the standard concentrations recommended by the Clinical and Laboratory Standards Institute (CLSI) and the American Society for Microbiology (ASM), and RIF, assessed through microdilution at 4 concentrations. RESULTS: The bacteria were Escherichia coli (55%), as the majority, in all its pathogenic variants, Shigella (16.8%), Salmonella (15.3%), Aeromonas (7.8%), and less than 5% Campylobacter, Yersinia, Vibrio, and Plesiomonas. The accumulated overall susceptibility to RIF was 69.1, 90.8, 98.9, and 100% at concentrations of 100, 200, 400, and 800µg/ml, respectively. Overall susceptibility to other antibiotics was FOS 82.8%, CHL 76.8%, CIP 73.9%, FUR 64%, T-S 58.7%, NEO 55.8%, and AMP 23.8%. Susceptibility to RIF at 400 and 800µg was significantly greater than with the other antimicrobials (P<.001). CONCLUSIONS: The data of the present study were similar to those of a previous study carried out in Mexico City: susceptibility to RIF in > 98% of the bacterial strains and a high frequency of resistance to several common antimicrobials.

Susceptibility of bacteria isolated from acute gastrointestinal infections to rifaximin and other antimicrobial agents in Mexico.

BACKGROUND: Bacterial resistance may hamper the antimicrobial management of acute gastroenteritis. Bacterial susceptibility to rifaximin, an antibiotic that achieves high fecal concentrations (up to 8,000µg/g), has not been evaluated in Mexico. OBJECTIVE: To determine the susceptibility to rifaximin and other antimicrobial agents of enteropathogenic bacteria isolated from patients with acute gastroenteritis in Mexico. MATERIAL AND METHODS: Bacterial strains were analyzed in stool samples from 1,000 patients with diagnosis of acute gastroenteritis. The susceptibility to rifaximin (RIF) was tested by microdilution (<100, <200, <400 and <800µg/ml) and susceptibility to chloramphenicol (CHL), trimethoprim-sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), fosfomycin (FOS), ampicillin (AMP) and ciprofloxacin (CIP) was tested by agar diffusion at the concentrations recommended by the Clinical & Laboratory Standards Institute and the American Society for Microbiology. RESULTS: Isolated bacteria were: enteropathogenic Escherichia coli (E. coli) (EPEC) 531, Shigella 120, non-Typhi Salmonella 117, Aeromonas spp. 80, enterotoxigenic E. coli (ETEC) 54, Yersinia enterocolitica 20, Campylobacter jejuni 20, Vibrio spp. 20, Plesiomonas shigelloides 20, and enterohemorrhagic E. coli (EHEC 0:157) 18. The overall cumulative susceptibility to RIF at <100, <200, <400, and <800µg/ml was 70.6, 90.8, 99.3, and 100%, respectively. The overall susceptibility to each antibiotic was: AMP 32.2%, T-S 53.6%, NEO 54.1%, FUR 64.7%, CIP 67.3%, CLO 73%, and FOS 81.3%. The susceptibility to RIF <400 and RIF <800µg/ml was significantly greater than with the other antibiotics (p<0.001). CONCLUSIONS: Resistance of enteropathogenic bacteria to various antibiotics used in gastrointestinal infections is high. Rifaximin was active against 99-100% of these enteropathogens at reachable concentrations in the intestine with the recommended dose.

Structure and morphology of thin films of linear aliphatic polyesters prepared by spin-coating.

Thin films, with thicknesses from 10 to 400 nm of linear aliphatic polyesters (X, Y), based on propylenediol (X = 3) and on dicarboxylic acid of different chain length (Y = 2, 3, and 4 CH(2) units) were prepared by spin coating of CHCl(3) polymer solutions with different polymer concentrations. Morphology and structure of the spin coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence X-ray scattering techniques at small, (GISAXS) and wide angles (GIWAXS). AFM revealed a strong dewetting for all three polymers for coatings thinner than 100 nm. The polymer films are clearly semicrystalline for thicknesses higher than 50 nm. GIWAXS of the thicker films revealed their oriented crystalline nature. An edge-on-lamellae morphology is clearly shown by the AFM-phase images even for relatively thin films. SAXS with the beam parallel to the sample plane also support the presence of lamellae perpendicular to the substrate. The use of a mu-beam helped to interpret the GIWAXS patterns and allowed to obtain oriented WAXS patterns from melt solidified filaments. Thus, a crystal chain packing is proposed for the three polymers and consequently the indexing of the observed reflections. Accordingly, the polymer chains lie parallel to the substrate being the bc plane of the monoclinic crystal unit cell parallel to the substrate.

Flat-on lamellae in spin-coated, stable films of poly(propylene azelate).

Thin films (5-500 nm thick) of the linear aliphatic polyester (3,7) poly(propylene azelate) (PPAz) were prepared by spin-coating of CHCl(3) polymer solutions with different polymer concentrations. The morphology and structure of the spin-coated thin films were investigated by atomic force microscopy (AFM) and by grazing incidence wide-angle X-ray scattering (GIWAXS) techniques. AFM revealed the continuous nature of the flat, spherulitic films which are stable against dewetting even for polymer coatings as thin as 15 nm. GIWAXS patterns revealed a high crystal orientation of the films. A sharp reflection on the meridian whose spacing is related to the polymer chain unit length (c-axis) supports the presence of flat-on lamellae morphology in the whole range of film thicknesses investigated. The flat-on lamellae morphology is also supported by AFM images. A triclinic unit cell with the c*-axis perpendicular to the substrate is proposed for PPAz. The repulsion of the long aliphatic spacer by the Si-substrate is invoked as the main reason for the flat-on morphology observed.

Efficacy of rifaximin in the different clinical scenarios of hepatic encephalopathy. / Eficacia de la rifaximina en los diferentes escenarios clínicos de la encefalopatía hepática.

Hepatic encephalopathy is a frequent complication in patients with cirrhosis of the liver and is associated with a high mortality rate. Costs attributed to the management of patients with cirrhosis are especially high due to complications, such as hepatic encephalopathy, given that they increase the number of days of hospital stay. Different drugs are currently used to treat hepatic encephalopathy, and the main ones are lactulose, L-ornithine L-aspartate (LOLA), and certain antibiotics, especially rifaximin-α (RFX). Even though many of them have been shown to be effective to greater or lesser degrees, it is important to understand the differences between them, so that every patient receives individualized treatment and the best option is chosen, in accordance with the different clinical scenarios. Thus, the aim of the present study was to analyze the evidence on the advantages and disadvantages of the individual or combined use of the 3 main treatments for hepatic encephalopathy, specifically taking into consideration their different degrees of efficacy, their impact on quality of life, prophylaxis, and cost reduction.

Bowel symptoms in patients that receive proton pump inhibitors. Results of a multicenter survey in Mexico. / Síntomas intestinales en pacientes que reciben inhibidores de bomba de protones (IBP). Resultados de una encuesta multicéntrica en México.

INTRODUCTION: Proton pump inhibitors (PPIs) have been associated with small intestinal bacterial overgrowth (SIBO), which increases with prolonged PPI use, and SIBO has been associated with irritable bowel syndrome (IBS). OBJECTIVE: The aim of the present study was to study the prevalence of bowel symptoms in patients treated with PPIs in Mexico. METHODS: Gastroenterologists in 36 cities surveyed patients treated with PPIs, utilizing an ad hoc questionnaire to determine the presence of bowel symptoms and IBS. RESULTS: Two hundred and fifteen physicians interviewed 1,851 patients. PPI indications were gastritis (48.8%), gastroesophageal reflux (38.5%), peptic ulcer (6.2%), and others (6.5%). A total of 77.5% of the patients received treatment for ≤6 months and 11.9% for ≥1 year. Symptoms were reported in 92.3% of the patients: abnormal bowel habits (90%), bloating (82%), abdominal pain (63%), flatulence (58%), and abdominal discomfort (53%). A total of 67.5% of the patients fit the Rome III criteria for IBS. Symptoms presented in 55.9% of the patients before PPI intake and in 44.1% of the patients after PPI use (P<.005). Constipation (63.8%) predominated in the former, and diarrhea (56.5%) in the latter (P<.0001). The treatments prescribed for managing those symptoms were antispasmodics, antibiotics, prokinetics, and antiflatulents, but patients stated greater satisfaction with antibiotics (mainly rifaximin) (P<.0001). CONCLUSION: The association of PPIs with bowel symptoms and IBS is frequent in Mexico. Diarrhea and bloating predominate, and antibiotics produce the greatest treatment satisfaction, suggesting that SIBO or dysbiosis is the cause of the PPI-related bowel symptoms. However, that remains to be confirmed.

Hemodynamic and oxidative stress profile after exercise in type 2 diabetes.

This study investigated the effect of an acute bout of exercise (>85% VO2Max) on biochemical, hemodynamic and oxidative stress variables in sedentary and physically active subjects with type 2 diabetes (T2D). Blood measurements were taken before and after a treadmill test on 12 sedentary non-diabetes subjects (ND), 12 sedentary type 2 diabetes (T2S) and 9 physically active T2D subjects (T2DA). T2DS subjects before and after the treadmill test showed a higher plasma glucose (123.2 +/- 19.0 mg/dL versus 108.9 +/- 16.8 mg/dL, p < 0.001), HbA1C (8.7 +/- 2.4% versus 7.3 +/- 1.2%, p < 0.001) and body fat% (21.3 +/- 5.7% versus 34.6 +/- 4.5%, p < 0.001) than T2DA subjects. T2DA had higher VO2Max (37.7 +/- 3.5 versus 29.5 +/- 3.2, p < 0.05), time on treadmill (22.3 +/- 2.1 min versus 16.1 +/- 2.1 min, p < 0.05), hemoglobin (17.9 +/- 0.9 g/dL, p < 0.05) and lower blood pressure levels in comparison to ND and T2DS subjects. Thiobarbituric acid substances (TBARS) in T2DS were higher than in T2DA subjects (0.27 +/- 0.1 nmol/mL versus 0.21 +/- 0.1 nmol/mL, p < 0.05). Glutathione (GSH) levels were similar among the groups. Physically active type 2 diabetes subjects had a more favorable biochemical, hemodynamic and oxidative stress profile than sedentary subjects. The coexistence of a poor cardiopulmonary performance and high oxidative stress environment can determine a profile of high risk for serious cardiovascular events in patients with diabetes.

Hypoglycemic effect of Opuntia streptacantha Lemaire in NIDDM.

To assess the hypoglycemic effect of the nopal Opuntia streptacantha Lemaire (O. streptacantha Lem.), three groups of patients with non-insulin-dependent diabetes mellitus (NIDDM) were studied. Group one (16 patients) ingested 500 g of broiled nopal stems. Group 2 (10 patients) received only 400 ml of water as a control test. Three tests were performed on group 3 (6 patients): one with nopal, a second with water, and a third with ingestion of 500 g broiled squash. Serum glucose and insulin levels were measured at 0, 60, 120, and 180 min. After the intake of O. streptacantha Lem., serum glucose and serum insulin levels decreased significantly in groups 1 and 3, whereas no similar changes were noticed in group 2. The mean reduction of glucose reached 17.6 +/- 2.2% of basal values at 180 min in group 1 and 16.2 +/- 1.8% in group 3; the reduction of serum insulin at 180 min reached 50.2 +/- 8.0% in group 1 and 40.3 +/- 12.4% in group 3. This study shows that the stems of O. streptacantha Lem. cause a hypoglycemic effect in patients with NIDDM. The mechanism of this effect is unknown, but an increased insulin sensitivity is suggested.

Multimedia and virtual reality techniques in the treatment of male erectile disorders.

The present study is based on the observation that computer-simulated reality applied by virtual reality (VR) methods may offer a new means of treating male erectile disorders. The experimental design was based on the theory of psychological development, supported by multimedia acoustic experience and clinical tests. The method involved the use of virtual reality equipment and specially designed CD-ROM programmes. Excluding 15% drop-outs, the success rate was 82% for male erectile disorders due to psychological factors and 84%, excluding 17% drop-outs, for combined factor disorders. Psychotherapy with VR seems to hasten the healing process and reduce drop-outs, suggesting that this method opens or consolidates new or rarely used brain pathways, facilitating the flow of new mnemonic associations that promote the satisfaction of natural drives.

Effect of plasma volume expansion on auricular natriuretic peptide in non-dependent insulin diabetic patients with autonomic neuropathy.

The objective of this study was to determine the role of atrial natriuretic peptide (ANP) in autonomic neuropathy and to learn the effect of saline solution infusion on ANP. Twenty one subjects were distributed in three groups: 1) control group, 2) diabetic patients with autonomic neuropathy, and 3) diabetic patients without autonomic neuropathy. The levels of ANP, renin, aldosterone and cortisol were determined at baseline and 30, 60, and 75 min after saline infusion. At baseline ANP was lower in diabetic patients with autonomic neuropathy (32.9 +/- 13) than control group (34 +/- 15). ANP increased statistically significantly at 30 min after solution administration in control group (60 +/- 35, F = 4, p < 0.05), but it did not change in diabetic patients (Group II: 34.3 +/- 9.3 and Group III 34.6 +/- 10.7). Sixty and 75 min after saline infusion ANP returned to basal levels in control group, but they did not change in diabetic patients. A delayed response of renin, aldosterone and cortisol to saline solution administration was observed in diabetic patients. There was no correlation between ANP levels and alteration of autonomic tests. It is concluded that independent of autonomic neuropathy, the levels of ANP did not increase with saline infusion in diabetic patients.

Lowering glycemic index of food by acarbose and Plantago psyllium mucilage.

BACKGROUND: A study was designed to evaluate the effect of acarbose and Plantago psyllium mucilage on glycemic index (GI) of bread. METHODS: Twelve patients with non-insulin-dependent diabetes mellitus (NIDDM) and ten healthy volunteers were studied. Three meal tests with an intake of 90 g of white bread (50 g of carbohydrates) were performed on each subject. In one test, 200 mg of acarbose was given, while 15 g of P. psyllium mucilage was given in another test, and only bread was ingested in the control test. Serum glucose and insulin concentrations were measured every 30 min from 0-180 min. Net area under curve (AUC) concentrations of glucose and insulin, GI and insulinic index were calculated. RESULTS: In NIDDM patients, AUC-glucose in the test with acarbose (1.9 +/- 0.7 mmol/L) and with P. psyllium (4.3 +/- 1.2 mmol/L) were significantly lower than in the control test (7.4 +/- 1.5 mmol/L) (p < 0.01). GI of bread plus acarbose was 26 +/- 13, and of bread plus P. psyllium, 59 +/- 10 (p < 0.05). AUC-insulin and insulinic index behave similarly. In healthy individuals, AUC-glucose and GI did not significantly change with the treatments; however, insulinic index with acarbose was 17 +/- 16, and with P. psyllium was 68 +/- 15 (p < 0.05). Acarbose or P. psyllium decreased GI of bread in NIDDM patients and diminished insulinic index in NIDDM and in healthy subjects. CONCLUSIONS: Adding acarbose or P. psyllium to meals may reduce glycemic index of carbohydrate foods and may help diabetic control.

Monounsaturated fatty acid (avocado) rich diet for mild hypercholesterolemia.

To assess the effect of a high monounsaturated fatty acids (MFA) diet on serum lipids, 30 healthy adult normolipidemic volunteers and 37 adult patients with mild hypercholesterolemia (5.4-9.3 mmol/l), 15 of them also with hypertriglyceridemia (2.3-4.8 mmol/l), were studied. Fifteen healthy and 30 hypercholesterolemic subjects (15 of them with associated type 2 diabetes mellitus) received an avocado enriched diet (2000 Kcal, lipids 53% MFA 49 g saturated/unsaturated ratio 0.54), and seven non-diabetic hypercholesterolemic individuals received an isocaloric control diet (MFA 34 g, saturated/unsaturated ratio 0.7). Serum total cholesterol, LDL-cholesterol, HDL-cholesterol and triglyceride concentrations were measured before and after a 7-day diet period. In healthy individuals a 16% decrease of serum total cholesterol level followed the high MFA diet, while it rose after the control diet (p < 0.001 between diets). In hypercholesterolemic subjects a significant (p < 0.01) decrease of serum total cholesterol (17%), LDL-cholesterol (22%) and triglycerides (22%), and increase of HDL-cholesterol (11%) levels occurred with the avocado diet, while no significant changes were noticed with the control diet. High lipid, high MFA-avocado enriched diet can improve lipid profile in healthy and especially in mild hypercholesterolemic patients, even if hypertriglyceridemia (combined hyperlipidemia) is present.

Risk factors for steroid diabetes in rheumatic patients.

BACKGROUND: Steroid induced diabetes (SDM) has been known for a long time, but its pathophysiological mechanisms as well as its predisposing factors remain unknown. METHODS: In order to investigate the different factors related to the development of steroid diabetes (SDM) in patients with rheumatic diseases, we studied 27 patients with SDM, and 27 age- and sex-matched controls who also received therapy with glucocorticoids. In every case, family history of DM, body mass index, associated treatment, steroid dose and treatment duration were studied; fasting serum insulin, "C" peptide, growth hormone and glucagon levels were measured. RESULTS: All of the patients received prednisone. Cumulated prednisone dose was the only factor significantly associated with the development of SDM. Patients with SDM had a cumulated dose of 26.6 +/- 28 g (M +/- SD), while the control group received 11.6 +/- 11 g (p < 0.02) (odds ratio, 6.35). Serum insulin levels were not significantly different, but insulin/glucose ratio was lower in SDM (0.104 +/- 0.05) than in the control group (0.163 +/- 0.07) (p < 0.05). CONCLUSIONS: These findings suggest that high cumulated prednisone dose may induce DM regardless of another hereditary or personal predisposing factor.

Oxidative stress, acute and regular exercise: are they really harmful in the diabetic patient?

Oxidative stress has been involved in the pathogenic process of a variety of diseases including diabetes mellitus. The production of oxidative reactive products has been involved in biochemical changes in bio-molecules that might produce tissue damage directly related to some of the main vascular complications in the diabetic patient. On the other hand, exercise, paradoxically, is a well-recognized model of oxidative stress and also an important therapeutic tool in diabetes management. Therefore, the relationship between oxidative stress and exercise in diabetic patients implies an interesting biochemical paradox due to some of the negative effects of exercise principally by the increase of oxidative species in plasma. The effect of oxidative stress during an acute exercise and after an aerobic training period on those patients remains unknown and needs to be studied.

PET supports the hypothesized existence of a male sexual brain algorithm that may respond to treatment combining psychotherapy with virtual reality.

Could a brain circuit exist, verifiable using positron emission tomography (PET), that links coitus and its dysfunctions, such as impotence? Could re-establishing normal sexual functioning be linked with the normalization of some sort of altered brain metabolism utilizing a therapeutic project that uses psychodynamic psychotherapy integrating virtual reality (VR)? A Brain PET Scan and a self-administered sexual activity questionnaire were given to 11 heterosexual patients affected by impotence due to psychological causes, both before and approximately 6 months after a cycle of psychodynamic psychotherapy. Seven randomly-selected patients received psychotherapy with VR technology using the Optale Method. PET data, used to indicate glucose consumption in various brain areas, were compared with data from normal patients, and a statistical analysis was run. Alterations in cerebral metabolic functioning were displayed in the following areas: frontal cortex, nucleus caudatus, and thalamus. The seven patients who received psychotherapy with VR technology "normalized" in these same areas and attained satisfactory sexual performance. The existence of a male sex algorithm may be hypothesized that links the frontal cortex, nucleus caudatus, and thalamus, and explains its action on cortical motor areas and/or on the medial preoptic area of the hypothalamus, which may respond to treatment combining psychotherapy with VR.

A VR based therapy for the treatment of impotence and premature ejaculation.

The use of psycho-dynamic psychotherapy integrating virtual reality (VR) dealt with in this study on the treatment of erection dysfunctions and premature ejaculation started several years ago, after having seen the scarce results we obtained using exclusively a psycho-dynamic approach (accompanied by pre-recorded sound and music). Considering the particular way that full-immersion VR involves the subject who experiences it, we hypothesized that better results could be obtained during therapy for these sexual disorders and in particular regarding the nature of erection dysfunction, commonly referred to as impotence "a persistent or recurrent inability to attain, or to maintain until completion of the sexual activity, an adequate erection." The plan for therapy consisted of 12 hour-long sessions over a 25-week period, and the methods involved the use of a VR helmet, joystick and miniature television screens that projected specially-designed CD-ROM programs on psychological development.

[Effect of fever on gastric emptying and on serum gastrin levels]. / Efecto de la fiebre sobre el vaciamiento gástrico y los niveles séricos de gastrina.

We studied the effect of fever on gastric emptying and serum gastrin 17 levels. 8 patients with fever and normal gastric emptying were selected. Blood samples were obtained for measuring serum gastrin 17. We used Tc99m scintiscanning to measure gastric emptying. Differences between fever and normal temperature were significant. Gastric emptying in fever was 118 +/- 54 minutes and 55 +/- 22 minutes for normal temperature (p less than .01). Serum gastrin was 47.7 +/- 13 pg/ml in normal temperature and with febrile patients was 30 +/- 5.7 pg/ml (p less than .002). We conclude that fever retards gastric emptying, perhaps independently of serum gastrin level.