Drug-Loaded Polymeric Composite Skin Graft for Infection-Free Wound Healing: Fabrication, Characterization, Cell Proliferation, Migration, and Antimicrobial Activity

Purpose

A new, injectable, drug-loaded composite graft was developed to enable infection free wound healing.

Methods

The graft was fabricated using gentamicin and biomimetic microparticulate scaffolds in gelatin gel and characterized for biologically relevant properties like fluid uptake, evaporative water loss (EWL), water vapor transmission rate (WVTR), Young’s modulus and degradation. It was evaluated for drug release, cytocompatibility and antimicrobial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa.

Results

Graft exhibited fluid uptake of 13.79%, EWL of 60–70% in 10?h, WVTR of 5480.31?g/m²/d, and Young’s modulus as 2.1–10.8?kPa. It exhibited 99.36% degree of crosslinking and a dual degradation behavior wherein, the carrier gel, gelatin, degraded rapidly leaving the microparticulate scaffolds intact. Drug release studies showed a sustained release of gentamicin for 13?days sufficient to inhibit the infection at the wound site. Cytocompatibility assessment of the graft revealed that graft supported cell adhesion, proliferation and migration. The antibacterial efficacy of the graft was assessed using Kirby-Bauer method and time kill assay, wherein results indicated a quick, effective (≥5-log reduction in CFU/ml) and long lasting antimicrobial effect.

Conclusions

These results as a whole indicate that the graft represents an effective alternative for infection-free healing of full thickness wounds.

Dimethyltryptamine and other hallucinogenic tryptamines exhibit substrate behavior at the serotonin uptake transporter and the vesicle monoamine transporter

N,N-dimethyltryptamine (DMT) is a potent plant hallucinogen that has also been found in human tissues. When ingested, DMT and related N,N-dialkyltryptamines produce an intense hallucinogenic state. Behavioral effects are mediated through various neurochemical mechanisms including activity at sigma-1 and serotonin receptors, modification of monoamine uptake and release, and competition for metabolic enzymes. To further clarify the pharmacology of hallucinogenic tryptamines, we synthesized DMT, N-methyl-N-isopropyltryptamine (MIPT), N,N-dipropyltryptamine (DPT), and N,N-diisopropyltryptamine. We then tested the abilities of these N,N-dialkyltryptamines to inhibit [³H]5-HT uptake via the plasma membrane serotonin transporter (SERT) in human platelets and via the vesicle monoamine transporter (VMAT2) in Sf9 cells expressing the rat VMAT2. The tryptamines were also tested as inhibitors of [³H]paroxetine binding to the SERT and [³H]dihydrotetrabenazine binding to VMAT2. Our results show that DMT, MIPT, DPT, and DIPT inhibit [³H]5-HT transport at the SERT with K _I values of 4.00 ± 0.70, 8.88 ± 4.7, 0.594 ± 0.12, and 2.32 ± 0.46 μM, respectively. At VMAT2, the tryptamines inhibited [³H]5-HT transport with K _I values of 93 ± 6.8, 20 ± 4.3, 19 ± 2.3, and 19 ± 3.1 μM, respectively. On the other hand, the tryptamines were very poor inhibitors of [³H]paroxetine binding to SERT and of [³H]dihydrotetrabenazine binding to VMAT2, resulting in high binding-to-uptake ratios. High binding-to-uptake ratios support the hypothesis that the tryptamines are transporter substrates, not uptake blockers, at both SERT and VMAT2, and also indicate that there are separate substrate and inhibitor binding sites within these transporters. The transporters may allow the accumulation of tryptamines within neurons to reach relatively high levels for sigma-1 receptor activation and to function as releasable transmitters.     

Sudden visual loss due to posterior ischemic optic neuropathy following craniotomy for a ruptured intracranial aneurysm

The authors report a rare case of acute ipsilateral blindness that occurred after a standard fronto-temporal craniotomy for aneurysm in supine position. Posterior ischemic optic neuropathy caused by external pressure on the ipsilateral eye, its differentials and subsequent medico-legal implications are discussed.     

The molecular basis of CO2 reception in Drosophila

CO(2) elicits a response from many insects, including mosquito vectors of diseases such as malaria and yellow fever, but the molecular basis of CO(2) detection is unknown in insects or other higher eukaryotes. Here we show that Gr21a and Gr63a, members of a large family of Drosophila seven-transmembrane-domain chemoreceptor genes, are coexpressed in chemosensory neurons of both the larva and the adult. The two genes confer CO(2) response when coexpressed in an in vivo expression system, the "empty neuron system." The response is highly specific for CO(2) and dependent on CO(2) concentration. The response shows an equivalent dependence on the dose of Gr21a and Gr63a. None of 39 other chemosensory receptors confers a comparable response to CO(2). The identification of these receptors may now allow the identification of agents that block or activate them. Such agents could affect the responses of insect pests to the humans they seek.     

Ten-year experience in the management of total colonic aganglionosis

Purpose

The aim of this study was to review the 10 years' experience in the management of patients with total colonic aganglionosis (TCA) and follow-up of their health condition.

Methods

Cases of 25 patients with TCA in the Children's Hospital of Fudan University from 1996 to 2005 were reviewed and analyzed. The confirmed diagnosis was established by an intraoperative frozen-section biopsy of the rectum, colon, appendix, and ileum. The data included in this study accounted for sex, age, signs of presentation, any familiar history of Hirschsprung disease (HD) or associated abnormalities, and ileal involvement. Plain x-ray films, barium enema, and anorectal manometry were provided for evaluation. The results of surgical management were analyzed for weight at definite operation, blood requirement during operation, the total parenteral nutrition duration, and the pre- and postoperative complications of these patients. Follow-up data were collected regarding growth development, stool frequency, stool consistency, fecal soiling, incontinence, enterocolitis, and anal stricture.

Results

Among 25 patients, 8 (32%) females and 17 (68%) males were diagnosed as having TCA. Sixteen patients (64%) were evaluated at the neonatal period, whereas 9 patients (36%) were evaluated after the neonatal period. All 25 patients received at least 1 plain abdominal radiograph or barium enema at the university hospital before operation.However, there was no specific pathognomonic finding that may provide a definite diagnosis. Nineteen (76%) patients underwent initial laparotomy at our institute and 6 patients (24%) were operated on beforehand at other hospitals. Twenty-three (92%) patients were diagnosed as having TCA and underwent ileostomy, whereas 2 (8%) patients underwent primary pull-through procedure. Eighteen (72%) patients had undergone definite surgery. Pre- and postoperative complications included enterocolitis (44.4%), perianal excoriation (77.7%), electrolyte imbalance (50%), and anastomotic leak (16.6%). Average duration of total parenteral nutrition before operation was 17.77 ± 12.54 days and after operation was 10.27 ± 5.23 days. Mean follow-up time was 27.6 ± 35.39 months. Two patients had 5 to 6 bowel movements per day. Seven had a frequency of stool ranging between 1 and 3 bowel movements per day. Their bowel movements returned to normal about 12 to 18 months after surgery. On follow-up, the height and weight development of the patients was found to be normal.

Conclusions

Gradual progress was observed in all the patients that took part in the study, and all patients had positive results eventually.     

Correlation of physical parameters during radiochemical synthesis of (18)F positron emission tomography radiopharmaceuticals

Positron emission tomography is a highly specialized imaging technique using short-lived radiolabel substances to produce extremely high resolution images of the body's biological function. The (18)F(-) ion is produced via the (18)O(p,n)(18)F reaction using a silver target cell filled with 1.4 mL of enriched [(18)O] water. On a typical run, the target is irradiated for 45 minutes with 16.5 MeV protons (on target) and an average beam current of 5-45 mA. When the same reaction takes place with [(16)O] water [(13)N] Ammonia is produced as the primary product by the abstraction of hydrogen from water. This study investigated the physical parameters of medical cyclotron during the radiochemical process with induced radioactivity flux and mutual correlation of physical parameters for 16.5 MeV medical cyclotron at the INMAS Delhi, India. It is observed that by getting farther from the target, the relative number of low-energy neutrons increases while the overall flux of neutrons decreases. This is due to multiple scattering of high-energy neutrons in the walls and eventually absorption of low-energy neutrons. The other parameters are also linked with each other which are correlatable.     

A simplified approach to vertical infraclavicular brachial plexus blockade using hand-held Doppler

In this observational study, we used Doppler ultrasound during the performance of vertical infraclavicular brachial plexus blockade. The success rate at inserting the needle at the point where the sound of the subclavian artery via Doppler reached its maximum audibility was compared with that of the classical insertion point. In 89 of the 100 patients, the medial or posterior cord was found at first needle pass. Using the Doppler point for insertion resulted in a significantly more lateral entry point compared with the classical point (P < 0.001) and was associated with a high success rate of infraclavicular block.     

Identification of the substrate binding region of vesicular monoamine transporter-2 (VMAT-2) using iodoaminoflisopolol as a novel photoprobe

Monoamines, such as serotonin, dopamine, and norepinephrine, are sequestered into synaptic vesicles by specific transporters (vesicular monoamine transporter-2; VMAT2) using energy from an electrochemical proton gradient across the vesicle membranes. Based on our previous studies using photoaffinity-labeling techniques in characterizing the VMAT2-specific ligands ketanserin and tetrabenazine, this study describes the synthesis and characterization of a fluorenone-based compound, iodoaminoflisopolol (IAmF), as a photoprobe to identify the substrate binding site(s) of VMAT2. Using vesicles prepared from rat VMAT2 containing recombinant baculovirus-infected Sf9 cells, we show the inhibition of [3H]5-hydroxytryptamine (5-HT) uptake and [3H]dihydrotetrabenazine (TBZOH) binding by aminoflisopolol and iodoaminoflisopolol. The interaction of [125I]IAmF with VMAT2 is highly dependent on the presence of ATP and an intact proton gradient. We report a simple and novel method to distinguish between a ligand and substrate using classic compounds such as [3H]5-HT and [3H]TBZOH by incubating the compound with the vesicles followed by washes with isotonic and hypotonic solutions. Using this method, we confirm the characterization of IAmF as a novel VMAT2 substrate. Sf9 vesicles expressing VMAT2 show reserpine- and tetrabenazine-protectable photolabeling by [125I]IAmF. [125I]IAmF photolabeling of recombinant VMAT2, expressed in SH-SY5Y cells with an engineered thrombin site between transmembranes 6 and 7, followed by thrombin digestion, retained photolabel in a 22-kDa fragment, indicating that iodoaminoflisopolol binds to the C-terminal half of the VMAT2 molecule. Thus, IAmF possesses a unique combination of VMAT2 substrate properties and a photoprobe and is, therefore, useful to identify the substrate binding site of the vesicular transporter.