Ordered nanopore arrays with large interpore distances via one-step anodization

Preparation of pre-patterned alumina substrates using bottom-up techniques compatible with nanotechnology applications is still a challenge. We present a novel methodology to achieve superior order in 'anodic' alumina with large interpore distances by a convenient one-step anodization process. The use of transparent insulators renders such anodic layers applicable as templates for nanostructured photovoltaic or photoelectrochemical devices.

Direct visualization of the interfacial position of colloidal particles and their assemblies

A method for direct visualization of the position of nanoscale colloidal particles at air-water interfaces is presented. After assembling hard (polystyrene, poly(methyl methacrylate), silica) or soft core-shell gold-hydrogel composite (Au@PNiPAAm) colloids at the air-water interface, butylcyanoacrylate is introduced to the interface via the gas phase. Upon contact with water, an anionic polymerization reaction of the monomer is initiated and a film of poly(butylcyanoacrylate) (PBCA) is generated, entrapping the colloids at their equilibrium position at the interface. We apply this method to investigate the formation of complex, binary assembly structures directly at the interface, to visualize soft, nanoscale hydrogel colloids in the swollen state, and to visualize and quantify the equilibrium position of individual micro- and nanoscale colloids at the air-water interface depending of the amount of charge present on the particle surface. We find that the degree of deprotonation of the carboxyl group shifts the air-water contact angle, which is further confirmed by colloidal probe atomic force microscopy. Remarkably, the contact angles determined for individual colloidal particles feature a significant distribution that greatly exceeds errors attributable to the size distribution of the colloids. This finding underlines the importance of accessing soft matter on an individual particle level.

Switching light with light--advanced functional colloidal monolayers

Colloidal monolayers comprising of highly ordered two dimensional crystals are of high interest to generate surface patterns for a variety of different applications. Mostly, unfunctionalized polymer or silica colloids are assembled into monolayers. However, the incorporation of functional molecules into such colloids offers a convenient possibility of implementing additional properties to the two-dimensional crystal. Here, we present the formation of novel functional colloidal monolayers with photoswitchable fluorescence. The miniemulsion polymerization technique was used to incorporate an appropriate dye system of a perylene-based fluorophore and a bis-arylethene as a photochrome in polymeric colloids in defined ratios. Upon irradiation with UV or visible light the photochrome reversibly isomerizes from the ring-closed form, which is able to absorb light of the emission wavelength of the fluorescent dye and the ring-open form, which is not. The fluorescence emission of the dye can thus be reversibly switched on and off with light even when embedded in colloids. The colloids were self-assembled at the air-water interface to produce hexagonally ordered functional monolayers and more complex binary crystals. We investigate in detail the influence of the polymeric matrix on the switching properties of the fluorophore/photochrome system and find that the rate constants for the photoswitching, which all lie in the same range, are less influenced by the polymeric environment than expected. We demonstrate the reversible switching of the fluorescence emission in self-assembled colloidal monolayers. The arrangement of broadly distributed functional colloids into ordered monolayers with high addressability was obtained by the formation of binary colloidal monolayers.

Topical capsaicin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patch

Topical capsaicin formulations are used for pain management. Safety and modest efficacy of low-concentration capsaicin formulations, which require repeated daily self-administration, are supported by meta-analyses of numerous studies. A high-concentration capsaicin 8% patch (Qutenza™) was recently approved in the EU and USA. A single 60-min application in patients with neuropathic pain produced effective pain relief for up to 12 weeks. Advantages of the high-concentration capsaicin patch include longer duration of effect, patient compliance, and low risk for systemic effects or drug-drug interactions. The mechanism of action of topical capsaicin has been ascribed to depletion of substance P. However, experimental and clinical studies show that depletion of substance P from nociceptors is only a correlate of capsaicin treatment and has little, if any, causative role in pain relief. Rather, topical capsaicin acts in the skin to attenuate cutaneous hypersensitivity and reduce pain by a process best described as 'defunctionalization' of nociceptor fibres. Defunctionalization is due to a number of effects that include temporary loss of membrane potential, inability to transport neurotrophic factors leading to altered phenotype, and reversible retraction of epidermal and dermal nerve fibre terminals. Peripheral neuropathic hypersensitivity is mediated by diverse mechanisms, including altered expression of the capsaicin receptor TRPV1 or other key ion channels in affected or intact adjacent peripheral nociceptive nerve fibres, aberrant re-innervation, and collateral sprouting, all of which are defunctionalized by topical capsaicin. Evidence suggests that the utility of topical capsaicin may extend beyond painful peripheral neuropathies.

[Vaginal prolapse and rectal obstruction. Treated with a vaginal vault mesh colpo suspension and laparoscopic resection rectopexy]

BACKGROUND

Stool outlet obstruction with incomplete or complete rectal prolapse combined with vaginal vault prolapse is a severe form of pelvic floor insufficiency. Combining laparoscopic resection rectopexy with a vaginal vault mesh colpo suspension is a possible way of correcting this defect.

METHOD

The safety of the combination was evaluated in 18 patients.

RESULTS

The procedure was performed successfully with no complications in 16 of the 18 patients. One patient suffered intraoperative rectal injury and therefore received no polypropylene mesh, and one showed intraoperative bleeding requiring transfusion. No secondary surgery was required. Hospital stay lasted an average of 11.4 days (range 8-20) and the urinary catheters could be removed after an average of 4.3 days (range 2-10). No urinary disturbances were noted at the time of hospital release. Short-term mild fever appeared in 28% of cases (5/18). There were two urinary tract infections. No disturbance in healing and no anastomotic insufficiency were observed. The duration of postoperative antibiotic therapy averaged 3 days (range 0-8).

CONCLUSION

The combination of laparoscopic resection rectopexy with a vaginal vault mesh colpo suspension might be safe. The close contact between the mesh and anastomosis might induce no increase in insufficiency. Long-term outcome must still be evaluated.

Konventionelle oder laparoskopische Operation der perforierten Appendizitis - Eine vergleichende Studie

INTRODUCTION

Laparoscopic therapy of complicated appendicitis is still discussed controversially. This retrospective study compared the clinical results of open and laparoscopic appendectomy in a single centre.

PATIENTS AND METHODS

Within a period of three years (1999 to 2001) 493 patients with suspected acute appendicitis were operated prospectively at a German district hospital (250 open appendectomies, 243 laparoscopic appendectomies). Twenty percent of the patients in every group had a complicated appendicitis (48 open, 44 laparoscopic appendectomies) and were analysed retrospectively considering demographic data, operative time, body mass index, preoperative inflammatory parameters (white blood cell count, C-reactive protein and body temperature) and postoperative complication rate.

RESULTS

Both groups were comparable with regard to demographic data. One patient of the laparoscopic group needed an open operation (conversion rate 2.3 %). The body mass index of the laparoscopic group was significantly higher (26.3 vs. 24.1 kg/m(2)). Preoperative white blood cell count, C-reactive protein, body temperature as well as postoperative antibiotic therapy and analgesics requirement were comparable in both groups. There was no significant difference between the length of operative time (open 48 min, laparoscopic 53.5 min). The postoperative hospital stay was significantly shorter in the laparoscopic group (8 vs. 9 days, p = 0.032). Complication rate was significantly lower in the laparoscopic group (11.5 vs. 35 %, p = 0.014).

CONCLUSION

Laparoscopic appendectomy is a safe procedure for the treatment of complicated appendicitis with a significantly decreased complication rate and shorter postoperative stay.

[Minimally invasive video-assisted thyroid resection (MIVAT)--a well accepted operative procedure]

INTRODUCTION

We report on our results of MIVAT operations.

METHOD

Nineteen Patients including 15 females and 4 males were operated with MIVAT, corresponding to 11 % of all patients undergoing an operation for benign goitre in our hospital. A single node of the thyroid gland within 30 mm and enlargement of a thyroid lobe up to 25 ml were the selection criteria. The median age was 34 years (range 16-61). We performed 2 thyroidectomies, 6 Hartley-Dunhill resections, 9 hemihyroidectomies and 2 enucleations. Eighteen patients (95 %) were followed-up postoperatively. The median follow-up period was 8 months (range 1 -21).

RESULTS

The median operation time was 83 min (range 60-124). The median preoperative thyroid gland volume was 25 ml (range 10-54) measured by ultrasound. The resected thyroid tissue ranged from 12 to 51 g (median 29 g). A statistical significant difference (P = 0.04 paired t-test) between the preoperative and postoperative estimated serum-calcium levels (2.31 vs. 2.25 mM) was observed. But both parameters were inside the physiological range. Paresis of the recurrent laryngeal nerve was not observed. 89 % of the patients rated the postoperative cosmetic result as very good and all patients would prefer this operation procedure once again.

CONCLUSION

The MIVAT procedure is a safe operation also in small groups with excellent cosmetic results postoperatively and a high acceptance by the patients.

Meckel's diverticulum: a disease associated with a colored clinical picture

Meckel's diverticulum is reported in only 1 or 2% of the population. In most cases, it is free of clinical symptoms. The diagnostic modalities are effective in only 60-70% of all cases. The diagnostic laparoscopy is a safe and effective method for patients suffering from unclear abdominal pain with the option of a definitive surgical therapy. We describe the case of a 10-year-old girl with recurrent abdominal pain caused by a chronic subileus due to a Meckel's diverticulum in combination with a fibrous cord from the base of diverticulum to the mesenterial root. Both were resected in a laparoscopic technique.

RS 23597-190: a potent and selective 5-HT4 receptor antagonist

1. The pharmacological properties of RS 23597-190 (3-(piperdine-1-yl)-propyl-4-amino-5-chloro-2-methoxy benzoate hydrochloride) have been studied in vitro and in vivo. 2. RS 23597-190 competitively antagonized 5-HT4 receptor-mediated relaxations of rat, carbachol precontracted oesophageal muscularis mucosae, (pA2 = 7.8 +/- 0.1; Schild slope = 1.2 +/- 0.2). Affinity estimates (-log KB) at 5-HT4 receptors using either renzapride or SC-53116 as agonists yielded a -log KB value of 8.0 +/- 0.01. In contrast, RS 23597-190 failed to antagonize contractile responses to 5-HT of guinea-pig ileal 5-HT3 receptors, even at concentrations up to 10 microM. 3. Increases in short-circuit current, induced by 5-HT, were studied in guinea-pig ileal mucosal sheets. Concentration-response curves to 5-HT were biphasic, with the high potency phase to 5-HT inhibited by RS 23597-190 and mimicked by 5-methoxytryptamine. The -log KB value for RS 23597-190 at the high potency phase was 7.3 confirming that 5-HT4 receptors mediated the high potency phase. 4. In rat isolated vagus nerve, 5-HT elicited a slow, maintained depolarization at low concentrations and a rapid, transient depolarization at higher concentrations. The high potency, slow depolarizing phase to 5-HT was abolished selectively in the presence of 1 microM RS 23597-190 and the low potency phase was abolished selectively in the presence of 1 microM ondansetron. These data confirm that 5-HT4 and 5-HT3 receptors mediated slow and fast depolarization responses, respectively. 5. At 5-HT3 binding sites in membranes from NG 108-15 cells, labelled by [3H]-quipazine, RS 23597-190 exhibited an apparent affinity (- log Ki) of 5.7 +/- 0.1. At 5-HT3 receptors in membranes from rat cerebral cortex, labelled by [3H]-RS 42358-197, the apparent affinity (- log Ki) of RS 23597-190 was also 5.7 +/- 0.1. In both studies, Hill coefficients were not significantly different from unity. At 5-HT1A, 5-HT2,muscarinic M1, M2, M3, M4 and dopamine D1 and D2 receptors, RS 23597-190 exhibited low apparent affinities, with all - log Ki values less than 5.5.6. Intravenous infusion of RS 23597-190 in the conscious, restrained rat antagonized the von Bezold Jarisch reflex induced by 2-methyl 5-HT, with an ID50 of 300 microg kg-1 min-1, i.v. In the anaesthetized,bilaterally vagotomized micropig, RS 23597-190 (6 mg kg-1, i.v.) antagonized 5-HT-induced tachycardia with a half-life of 77 (63-99) min. Transient arrhythmic effects were noted after administration of the compound.7. In conclusion, RS 23597-190 acts as a high affinity, selective competitive antagonist at 5-HT4 receptors. Thus, the compound appears to be a useful tool for 5-HT4 receptor identification in vitro. In vivo, the compound is rapidly metabolized in pigs such that 5-HT4 blockade is not maintained. However,in the rat, when given by infusion, RS 23597-190 antagonizes 5-HT3 mediated responses, at doses consistent with a low affinity 5-HT3 receptor. These data suggest that, under appropriate experimental conditions, RS 23597-190 may also be used in vivo to characterize further 5-HT4 receptor function.