Porous Nanogold/Polyurethane Scaffolds with Improved Antibiofilm, Mechanical, and Thermal Properties and with Reduced Effects on Cell Viability: A Suitable Material for Soft Tissue Applications

The use of implants carries on a series of problems, among them infections, poor biocompatibility, high levels of cytotoxicity, and significant mechanical differences between implants and host organs that promote stress shielding effects. These problems indicate that the materials used to make implants must meet essential requirements and high standards for implantations to be successful. In this work, we present the synthesis, characterization and evaluation of the antibiofilm, mechanical, and thermal properties, and cytotoxic effect of a nanocomposite-based scaffold on polyurethane (PU) and gold nanoparticles (AuNPs) for soft tissue applications. The effect of the quantity of AuNPs on the antibacterial activity of nanocomposite scaffolds was evaluated against Staphylococcus epidermidis and Klebsiella spp., with a resulting 99.99% inhibition of both bacteria using a small quantity of nanoparticles. Cytotoxicity was evaluated with the T10 1/2 test against fibroblast cells. The results demonstrated that porous nanogold/PU scaffolds have no toxic effects on fibroblast cells to the 5 day exposition. With respect to mechanical properties, stress-strain curves showed that the compressive modulus and yield strength of PU scaffolds were significantly enhanced by AuNPs (by at least 10 times). This is due to changes in the arrangement of hard segments of PU, which increase the stiffness of the polymer. Thermogravimetric analysis showed that the degradation onset temperature rises with an increase in the quantity of AuNPs. These properties and characteristics demonstrate that porous nanogold/PU scaffolds are suitable material for use in soft tissue implants.

α-SNAP is expressed in mouse ovarian granulosa cells and plays a key role in folliculogenesis and female fertility

The balance between ovarian folliculogenesis and follicular atresia is critical for female fertility and is strictly regulated by a complex network of neuroendocrine and intra-ovarian signals. Despite the numerous functions executed by granulosa cells (GCs) in ovarian physiology, the role of multifunctional proteins able to simultaneously coordinate/modulate several cellular pathways is unclear. Soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (α-SNAP) is a multifunctional protein that participates in SNARE-mediated membrane fusion events. In addition, it regulates cell-to-cell adhesion, AMPK signaling, autophagy and apoptosis in different cell types. In this study we examined the expression pattern of α-SNAP in ovarian tissue and the consequences of α-SNAP (M105I) mutation (hyh mutation) in folliculogenesis and female fertility. Our results showed that α-SNAP protein is highly expressed in GCs and its expression is modulated by gonadotropin stimuli. On the other hand, α-SNAP-mutant mice show a reduction in α-SNAP protein levels. Moreover, increased apoptosis of GCs and follicular atresia, reduced ovulation rate, and a dramatic decline in fertility is observed in α-SNAP-mutant females. In conclusion, α-SNAP plays a critical role in the balance between follicular development and atresia. Consequently, a reduction in its expression/function (M105I mutation) causes early depletion of ovarian follicles and female subfertility.

Strategies for improving safety performance in construction firms

Over the years many prevention management practices have been implemented to prevent and mitigate accidents at the construction site. However, there is little evidence of the effectiveness of individual or combined practices used by companies to manage occupational health and safety issues. The authors selected a sample of 1180 construction firms and 221 individual practices applied in these companies to analyze their effectiveness reducing injury rates over a period of four years in Chile. Different methods were used to study this massive database including: visual analyses of graphical information, statistical analyses and classification techniques. Results showed that practices related to safety incentives and rewards are the most effective from the accident rate viewpoint, even though they are seldom used by companies; on the other hand, practices related to accidents and incidents investigation had a slight negative impact on the accident rate because they are frequently used as a reactive measure. In general, the higher the percentage of prevention practices implemented in a strategy, the lower the accident rate. However, the analysis of the combined effect of prevention practices indicated that the choice of the right combination of practices was more important than just the number of practices implemented.

Distinct Biochemical Pools of Golgi Phosphoprotein 3 in the Human Breast Cancer Cell Lines MCF7 and MDA-MB-231

Golgi phosphoprotein 3 (GOLPH3) has been implicated in the development of carcinomas in many human tissues, and is currently considered a bona fide oncoprotein. Importantly, several tumor types show overexpression of GOLPH3, which is associated with tumor progress and poor prognosis. However, the underlying molecular mechanisms that connect GOLPH3 function with tumorigenicity are poorly understood. Experimental evidence shows that depletion of GOLPH3 abolishes transformation and proliferation of tumor cells in GOLPH3-overexpressing cell lines. Conversely, GOLPH3 overexpression drives transformation of primary cell lines and enhances mouse xenograft tumor growth in vivo. This evidence suggests that overexpression of GOLPH3 could result in distinct features of GOLPH3 in tumor cells compared to that of non-tumorigenic cells. GOLPH3 is a peripheral membrane protein mostly localized at the trans-Golgi network, and its association with Golgi membranes depends on binding to phosphatidylinositol-4-phosphate. GOLPH3 is also contained in a large cytosolic pool that rapidly exchanges with Golgi-associated pools. GOLPH3 has also been observed associated with vesicles and tubules arising from the Golgi, as well as other cellular compartments, and hence it has been implicated in several membrane trafficking events. Whether these and other features are typical to all different types of cells is unknown. Moreover, it remains undetermined how GOLPH3 acts as an oncoprotein at the Golgi. Therefore, to better understand the roles of GOLPH3 in cancer cells, we sought to compare some of its biochemical and cellular properties in the human breast cancer cell lines MCF7 and MDA-MB-231 with that of the non-tumorigenic breast human cell line MCF 10A. We found unexpected differences that support the notion that in different cancer cells, overexpression of GOLPH3 functions in diverse fashions, which may influence specific tumorigenic phenotypes.

A data portal for regional climatic trend analysis in a Peruvian High Andes region

Abstract. In the frame of a Swiss-Peruvian climate change adaptation initiative (PACC), operational and historical data series of more than 100 stations of the Peruvian Meteorological and Hydrological Service (SENAMHI) are now accessible in a dedicated data portal. The data portal allows for example the comparison of data series or the interpolation of spatial fields as well as download of data in various data formats. It is thus a valuable tool supporting the process of data homogenisation and generation of a regional baseline climatology for a sound development of adequate climate change adaptation measures. The procedure to homogenize air-temperature and precipitation data series near Cusco city is outlined and followed by an exemplary trend analysis. Local air temperature trends are found to be in line with global mean trends.

Target-controlled infusion of remifentanil or fentanyl during extra-corporeal shock-wave lithotripsy

BACKGROUND AND OBJECTIVE

Target-controlled infusions (TCIs) of remifentanil and fentanyl in conscious sedation regimes for extra-corporeal shock-wave lithotripsy have not been reported. We estimated the effect site concentrations of remifentanil and fentanyl needed to obtain adequate analgesia in 50% of patients (EC50) and compared both drugs in terms of intra- and post-procedure complications.

METHODS

Forty-four adult patients were randomly distributed into two groups: Group R received remifentanil and Group F received fentanyl TCI with initial effect site concentrations of 1.5 and 2 ng mL(-1), respectively. Pain was assessed using a 10-point verbal analogue scale and <3 was considered adequate analgesia. Increments or decrements of 0.5 ng mL(-1) were then introduced for subsequent patients according to Dixon's up and down method. During the rest of the procedure, TCI was adjusted to maintain verbal analogue scale <3.

RESULTS

Remifentanil and fentanyl EC50 were 2.8 ng mL(-1) (95% confidence interval (CI): 1.8-3.7 ng mL(-1)) and 2.9 ng mL(-1) (95% CI: 1.7-4.1 ng mL(-1)), respectively (n.s.). At EC50, the probability of having a respiratory rate <10 was 4% (95% CI: 0-57%) for remifentanil and 56% (95% CI: 13-92%) for fentanyl. Hypoxaemia, vomiting and sedation were more frequent in Group F during and after the procedure (P < 0.05).

CONCLUSIONS

A similar EC50 but more respiratory depression, sedation and PONV were found with fentanyl TCI than with remifentanil TCI.

[Suprahepatic vein catheterization in 4 cases of severe septic shock]

Splanchnic hypoperfusion, with pathogenic implications for multiple organ failure, can occur during septic shock. We report four patients with septic shock in whom regional hepatosplenic splanchnic perfusion was monitored through suprahepatic vein catheterization and gastric tonometry. Suprahepatic lactate and oxygen saturation showed splanchnic hypoperfusion in all patients. These parameters improved only in the patient that survived. Gastric tonometry was more inconsistent. We conclude that suprahepatic vein catheterization could have a role in the management of septic shock.

[Use of amphotericin B in lipid emulsions: does it prevent its toxicity in critically ill patients?]

BACKGROUND

Amphotericin B is efficacious for the treatment of systemic candidiasis, however it has potentially serious toxic effects. Administration as lipid emulsions has been advocated to decrease its toxicity.

AIM

To compare the safety and tolerance of amphotericin B administered as lipid emulsion or dissolved in dextrose in water.

PATIENTS AND METHODS

Forty five patients with confirmed or highly suspected systemic candidiasis were studied. Between January 1996 and June 1997 amphotericin B was administered in dextrose in water to 17 patients (group 1). Between July 1997 and December 1998, the drug was delivered in lipid emulsions (Intralipid, group 2). Clinical and laboratory parameters (serum creatinine, urea nitrogen and potassium), were assessed daily.

RESULTS

Both treatment groups were clinically comparable and had the same survival. Accumulative amphotericin B dose administered was 343.2 +/- 197 and 414.6 +/- 518 mg respectively. Hypokalemia was more frequent in group 2 (52 and 25% respectively, p < 0.05). There were no differences in the outcome of renal function or other adverse reactions.

CONCLUSIONS

Administration of amphotericin B as lipid emulsions did not reduce its toxicity in critical patients (Rev Méd Chile 2000; 128: 1101-07).

Absolute linkage of celiac disease and dermatitis herpetiformis to HLA-DQ

This report shows the absolute genetic linkage of celiac disease (CD) to the HLA-DQ region, and supports the fact that dermatitis herpetiformis (DH) follows the same pattern of HLA-mediated susceptibility in extensive series of Caucasian Spanish patients. Ninety-five percent of CD (201 of 212) and 100% of DH (55) patients could produce DQ alpha 1*0501-DQ beta 1*02 heterodimers. Negative CD patients for this combination were mostly DR4-DQ8 (DQA1*03-DQB1*0302) (9 OF 11), along with a restricted number of complementary chromosomes. Comparison of observed and expected DQA1-DQB1 genotype distributions (Hardy-Weinberg equilibrium) showed that the excess of patients with DQB1*02 in double doses would be the consequence for which this allele should be complemented by DQA1*0501. Homozygosity for DQA1*0501 would restrain susceptibility to CD and DH.

Development of vestibular and auditory function: effects of hypothyroidism and thyroxine replacement therapy on nystagmus and auditory evoked potentials in the pigmented rat

The functional development of semicircular canals and some brainstem structures of the auditory system was followed in parallel with time in control and propylthiouracyl-induced hypothyroid pigmented rats by respective recording of postrotatory nystagmus response and auditory evoked brainstem potentials, with the aim of discovering the timing of permanent alterations of these responses in congenital hypothyroidism. A group of hypothyroid rats which under went thyroxine-replacement therapy from postnatal day 12 onward was also included in our studies to corroborate the involvement of thyroid hormones in these effects. Postrotatory nystagmus and auditory evoked responses were absent in congenital hypothyroid rats. In the thyroxine-replaced group postrotatory nystagmus values showed no differences from the control group from postnatal day 28 onward. Auditory evoked potentials in thyroxine-replaced animals could not be elicited at 30 dB, but by increasing the intensity of stimulus to 70 dB, values of latencies of the four waves composing the response were indistinguishable from controls from postnatal day 39 and thereafter. These results show that hypothyroidism affects both semicircular canal and auditory function, the latter more severely than the former, but that these effects can be prevented when thyroxine replacement treatment is started in early stages of postnatal development.

Development of vestibular function: biochemical, morphological and electronystagmographical assessment in the rat

Glutamate decarboxylase and choline acetyltransferase were measured in homogenated ampullar cristae of rats during development from postnatal day 13 to 60 to determine changes in levels of these enzymes during early postnatal development. Afferent and efferent innervation of the hair cells of the developing cristae were studied using electron microscopy. In parallel, groups of rats, postrotatory nystagmus were used to assess the development of semicircular canal function during the same time interval. The level of glutamate decarboxylase was high on postnatal day 15 and did not change notably over the remaining days to day 60. Activity of choline acetyltransferase was nearly absent at day 15, but reached levels seen in mature animals by day 17, and remained almost unchanged thereafter. In contrast, as revealed by electronmicroscopy, afferent and efferent innervation appeared to be mature by day 8. Postrotatory nystagmus presented the adult-like features from day 19 onward. According to these results, a role for glutamate decarboxylase in afferent transmission is suggested by the parallel development of levels of glutamate decarboxylase and afferent innervation of the ampullary cristae. The finding of a similar time course of development of choline acetyltransferase levels and postrotatory nystagmus suggests that a cholinergic efferent innervation is involved in the onset of vestibular-ocular function.

Vestibular site of action of hypothyroidism in the pigmented rat

The vestibular cell type affected by congenital hypothyroidism (CH) was investigated by measuring the activity of glutamate decarboxylase (GAD) and choline acetyltransferase (ChAT), synthesizing enzymes of putative afferent (GABA) and efferent (acetylcholine, ACh) neurotransmitters and thus, respectively, hair cell I and II (HC-I, HC-II), and efferent terminal (ET) marker enzymes, in vestibular homogenates of control, congenitally hypothyroid rats (CHR) and in thyroxine-replaced CHR (CHR-T4) whose postnatal age ranged from 20 to 60 days old. In the vestibule, CH-II and its efferent cholinergic contacting bouton mature prior to thyroid function whereas HC-I-differentiation and its efferent synapse arrival are the latest events in vestibular maturation. Therefore, a differential effect of CH upon GAD and ChAT in CHR could be anticipated. In control rats as in CHR the magnitude of GAD was the same with time starting on the 20th day. In CHR, ChAT gradually diminished beginning on day 28 to become 45% decreased with respect to control on the 60th postnatal day. Prevention of ChAT decrease in CHR by early administration of thyroxine (T4), a striking diminution of T4 and triiodothyronine (T3) in CHR serum and a normal level of these hormones found in CHR-T4 corroborated thyroid involvement. These results confirm the preference of hypothyroidism to affect cholinergic cell types (or compartments) of late maturation (HC-I-containing ET and hence 45% ChAT decrease) leaving HC-I, HC-II and HC-II-connecting ET untouched, supported by a 55% remanent ChAT and a constant GAD activity regardless of time and treatment.

Relationship between adenohypophyseal and steroid hormones and variations in serum and urinary melatonin levels during the ovarian cycle, perimenopause and menopause in healthy women

Morning levels of serum melatonin, FSH, LH, prolactin (PRL), progesterone and estradiol were studied by RIA during the ovarian cycle, perimenopause and menopause in 79 healthy women. FSH and LH levels showed a slight nonsignificant increase from the fertile period to perimenopause, exhibiting a significantly greater increase during menopause. PRL, progesterone and estradiol showed parallel changes, reaching lower levels during menopause. Serum melatonin levels decreased with age, attaining minimum levels in menopause. FSH and estradiol were significantly correlated with melatonin in the follicular phase, while in the luteal phase a negative correlation was found between melatonin, progesterone and estradiol. No significant correlations were noted between serum hormone levels during the perimenopausal period. In menopause, as during the follicular phase, melatonin and FSH were negatively correlated. As expected, a significant positive correlation was found between morning serum levels of melatonin and nocturnal urinary excretion of this indoleamine in all groups studied.

Influence of the pituitary-adrenal axis on benzodiazepine receptor binding to rat cerebral cortex

The role of the pituitary-adrenal axis on receptor binding and diurnal rhythmicity of benzodiazepines (BNZ) was assessed in the rat cerebral cortex. Groups of intact, adrenalectomized (ADx) and/or hypophysectomized (HPx) rats were killed at six different time intervals during the 24-hour cycle. BNZ binding was estimated by Scatchard analysis of 3H-flunitrazepam high-affinity binding to rat cerebral cortex. Intact and sham ADx animals show a similar pattern in diurnal thythm of BNZ binding, with a maximal concentration at midnight. Bilateral ADx induced a significant increase in Bmax at all time intervals studied, the largest rise appearing at midnight. HPx alone led to a slightly smaller rise in Bmax than in ADx rats, while HPx performed in ADx rats did not modify the response to ADx alone. Bmax of BNZ binding in ADx rats reached maximal values at 3-7 days after surgery, and decreased somewhat at 15 days post-ADx. Corticosterone administration at a single dose of 5 mg i.p. 24 h before sacrifice returned Bmax to normal values in ADx as well as in ADx plus HPx rats. The corticosterone effect is not exerted on the BNZ binding sites themselves, as revealed by the lack of effect of this glucocorticoid in vitro. These findings indicate that BNZ receptors in rat cerebral cortex can be modified by the adrenal gland, with corticosterone as a primary effector.

Lesions in suprachiasmatic nuclei simulate effects of pinealectomy on prolactin release in ovariectomized and sulpiride-treated female rats

Previous studies indicate that the pineal gland alters prolactin secretion, and it was suggested that at least part of the effect of the pineal hormone melatonin on prolactin release may be mediated by the hypothalamic structures. In this study, pinealectomy and lesions of the suprachiasmatic nuclei were found to alter serum levels of prolactin in the same direction, an effect that was counteracted by daily afternoon melatonin administration. Melatonin, but not other pineal indoles, also prevented sulpiride-induced prolactin secretion in pinealectomized or suprachiasmatic nuclei-lesioned and ovariectomized rats, which suggested that the pineal gland can modulate prolactin secretion by acting through a dopamine mechanism independent of hypothalamic suprachiasmatic structures.

Effects of selective and non-selective beta 1-blockade on renin secretion in the isolated rat kidney

The participation of beta 1-adrenoceptor on renin secretion was studied in perfused rat kidney. Administration of propranolol, inhibited the renin release mediated by isoproterenol. Likewise, metoprolol and practolol, showed a similar potency to propranolol in inhibiting isoproterenol-induced renin secretion. These results suggest that the for isoproterenol-induced renin release in rats is a beta 1-type adrenoceptor.

Role of pineal gland in kidney-adrenal homeostasis

The effects of pineal gland on kidney-adrenal axis have been studied in male rats. Rats were pinealectomized and exposed to a photoperiod of 12 h light: 12 h dark. Plasma renin activity (PRA), corticosterone and corticotropin (ACTH) levels were measured at 10, 20 and 35 days postpinealectomy. Pinealectomy increased corticosterone and ACTH levels and decreased PRA in all age groups. A significant negative correlation was found between corticosterone and PRA, which suggest that changes in PRA were due to changes in circulating corticosterone, via feedback mechanism on renin secretion. On the other hand, melatonin administration prevents these effects of pinealectomy. It is suggested that the lack of this pineal indol is responsible for the pinealectomy-induced alterations in male rats.

Inhibition of the renin-angiotensin system by pinealectomy in female rats

The influence of the pineal gland on the renin-angiotensin system has been studied in female rats. Pinealectomy produces a decreased plasma renin activity (PRA) concomitant with an increased corticosterone level, and with no changes in plasma aldosterone. Administration of indol melatonin reverses the effects of pinealectomy. On the other hand ovariectomy induces an increased PRA while decreasing corticosterone and aldosterone levels. However when pinealectomy and ovariectomy are both performed, neither PRA nor corticosterone changes. These results suggest that the pineal gland may exert an influence on the renin-angiotensin system via adrenal and/or ovarian pathways.

Calcium and renin release: inhibition of low sodium-induced renin secretion by high calcium concentration in rat kidney perfusion

The effects of changes in calcium on renin secretion have been studied in the isolated perfused rat kidney. Perfusion with free calcium buffer significantly decreases renin secretion as compared with control experiments (Ca++: 2.5 mM/l). Other calcium concentrations (1.25 mM/l) and 5 mM/l) do not affect basal renin secretion. When the renin release is previously increased by low sodium concentration (Na+: 110 mM/l) however, perfusion with high calcium buffer (Ca++: 5 mM/l) significantly inhibits this stimulation.

Increased activity of the renin-angiotensin-aldosterone system during the perinatal period

Plasma renin activity (PRA), plasma renin substrate (PRS), plasma renin concentration (PRC), and plasma aldosterone concentration (PAC) were measured in normal full-term newborn infants and infants up to 22 days after birth (36 in all). As compared to the control, PRA and PAC levels were significantly higher (p less than 0.001) in cord blood, and in 2 to 6 and 12 to 22 day old infants. The high values of PRA in 2 to 6 day old infants were due to the high PRS values. In cord blood and in 12 to 22 day old infants, however, the high levels of PRA reflect elevation of PRC. No correlation was found between PRA, PAC and serum potassium in cord blood and in 2 to 6 day old infants, but there was a significant correlation between the parameters (r = 0.72 and p less than 0.02) in 12 to 22 day old infants, indicating that at this age, as in healthy adults, the renin-angiotensin system and serum potassium seem to be the major stimuli for aldosterone secretion.

The effect of orthostatism, passive tilting and recumbent exercise on renin release

Three postural tests, orthostatism, passive tilting and recumbent exercise, were applied to fourteen normal volunteers. Orthostatism and tilting produce a significant increase in plasma renin activity (PRA) and plasma renin concentration (PRC), without changes in plasma renin substrate concentration (PSC). Recumbent exercise induces an inhibition of PRA and PRC and does not changes PSC. The present study seems to suggest that sympathetic activity and intravascular blood volume could play an important role in the responses of the renin-angiotensin system to postural changes.

Schwannoma of the brachial plexus with intrathoracic extension

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Effect of sodium and osmolarity on renin secretion

The effect of changes in sodium and osmolarity on renin secretion has been studied in the isolated perfused rat kidney. Perfusion with low sodium buffer (110 mM/l) produced a significant increase in renin secretion compared with control experiments (Na+:135 mM/l). Since the presence of tubules seems necessary for such an effect to take place, it suggests that the high renin secretion stimulated by a low sodium buffer centers in the Macula densa. Perfusion with high sodium buffer (170 mM/l; osmolarity 350 mOs/l) induces a stimulation on renin release. However, a greater rise in renin is achieved in control experiments if choline chloride increases the osmolarity from 300 to 350 mOs/l. All this suggests that high sodium buffer, independently of its osmotic effect, has an inhibitory role on renin release.

[Effects of postural changes and volume depletion on renin-angiotensin system (author's transl)]

The effects of orthostatism and furosemide tests on different parameters of renin-angiotensin system have been studied in 14 normal human subjects. Both tests produced a significant increase in plasma renin activity and plasma renin concentration. Plasma substrate concentration was slightly, but significantly, increased on the furosemide test. Plasma aldosterone rose in both tests, while aldosterone urinary excretion decreased after orthostatism and increased after furosemide.