- MeSH
- Doxorubicin pharmacology MeSH
- Hydroxamic Acids MeSH
- Humans MeSH
- Methacrylates MeSH
- Neoplasms * drug therapy MeSH
- Nanomedicine * MeSH
- Polymers pharmacology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Recently, controlled and sustained drug delivery has become the standard in modern pharmaceutical design and an intensive research has been undertaken in achieving much better drug product effectiveness, reliability and safety. In this regard, many polymers are very useful with majority of hydrogels, which undergo reversible volume and/or sol-gel phase transitions in response to physiological (temperature, pH and present of ions in organism fluids, blood glucose level) or other external (electric current, light) stimuli. This article reviews the main stimuli-sensitive hydrogels and the use of these hydrogels in parenteral, ocular, peroral, rectal, vaginal, nasal, dermal and transdermal drug delivery.
Tento návrh jednoduché metody vizualizace daktyloskopických stop na základě elektrochemické depozice polyfenazinových barviv (polyneutrální červeně a polytoluidinové modři) z neutrálního prostředí, kdy je minimalizováno poškození genetické informace, by mohl usnadnit snímání otisků prstů z nábojnic ve forenzní praxi. Parametry elektrochemických metod cyklické voltametrie a chronoamperometrie (základní elektrolyt, aplikovaný potenciál, doba depozice nebo potenciálový rozsah a počet cyklů) byly postupně optimalizovány, dokud nebyl otisk dostatečně viditelný. Morfologie a struktura modifikovaných povrchů daktyloskopických stop a polyfenazinových filmů byly studovány pomocí skenovací elektronové mikroskopie. Je předpokládán další rozvoj metody a především aplikace metody na vystřelené nábojnice.
A simple fingerprint visualization method based on the electrochemical deposition of polytoluidine blue (PTB) and polyneutral red (PNR) from a neutral environment with the possibility of minimal damage to the genetic information could facilitate fingerprinting from cartridge cases in forensic practice. The parameters of both visualization methods (supporting electrolyte, applied potential, deposition time or potential range, and number of cycles) were optimized until the imprint was sufficiently visible. The morphology and structure of modified fingerprint surfaces and polyphenazine films were studied using scanning electron microscopy. It is assumed that the method will be applied in the future to fired cartridges, which are crucial in forensics.
Nano-sized carriers are widely studied as suitable candidates for the advanced delivery of various bioactive molecules such as drugs and diagnostics. Herein, the development of long-circulating stimuli-responsive polymer nanoprobes tailored for the fluorescently-guided surgery of solid tumors is reported. Nanoprobes are designed as long-circulating nanosystems preferably accumulated in solid tumors due to the Enhanced permeability and retention effect, so they act as a tumor microenvironment-sensitive activatable diagnostic. This study designs polymer probes differing in the structure of the spacer between the polymer carrier and Cy7 by employing pH-sensitive spacers, oligopeptide spacers susceptible to cathepsin B-catalyzed enzymatic hydrolysis, and non-degradable control spacer. Increased accumulation of the nanoprobes in the tumor tissue coupled with stimuli-sensitive release behavior and subsequent activation of the fluorescent signal upon dye release facilitated favorable tumor-to-background ratio, a key feature for fluorescence-guided surgery. The probes show excellent diagnostic potential for the surgical removal of intraperitoneal metastasis and orthotopic head and neck tumors with very high efficacy and accuracy. In addition, the combination of macroscopic resection followed by fluorescence-guided surgery using developed probes enable the identification and resection of most of the CAL33 intraperitoneal metastases with total tumor burden reduced to 97.2%.
- MeSH
- Stimuli Responsive Polymers * MeSH
- Fluorescence MeSH
- Fluorescent Dyes chemistry MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Tumor Microenvironment MeSH
- Head and Neck Neoplasms * diagnostic imaging surgery MeSH
- Polymers MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Keywords
- nanosondy, označení nádoru, hranice nádoru,
- MeSH
- Stimuli Responsive Polymers MeSH
- Humans MeSH
- Neoplasms * surgery MeSH
- Nanotechnology methods MeSH
- Check Tag
- Humans MeSH
Smart hydrogels are special type of hydrogels that undergo solution-gelation transition in response to alterations in the environment. Solution-gel transformation is brought about through either physical or chemical cross-linking that occur between the hydrogel chains. Various stimulating factors have been identified to be responsible for the change in the physical state of the intelligent hydrogel. The most important triggering factors are the temperature, pH, ions, electrical signalling, magnetic field, glucose, light and others. Each of these stimulating factors can trigger the swelling of the hydrogel through unique mechanism. Many of these triggering factors are characteristics of the biological systems which make the smart polymers quite beneficial for different biomedical applications. Numerous natural and synthetic polymers have been distinguished to act as smart materials. These polymers impressed the scientists to use them in many biomedical and industrial applications such as drug delivery systems, gene therapy applications, tissue engineering and many other applications.
We performed a systematic study to check whether neurons in the area TE (the anterior part of inferotemporal cortex) in rhesus monkey, regarded as the last stage of the ventral visual pathway, could be modulated by auditory stimuli. Two fixating rhesus monkeys were presented with visual, auditory or combined audiovisual stimuli while neuronal responses were recorded. We have found that the visually sensitive neurons are also modulated by audiovisual stimuli. This modulation is manifested as the change of response rate. Our results have shown also that the visual neurons were responsive to the sole auditory stimuli. Therefore, the concept of inferotemporal cortex unimodality in information processing should be re-evaluated.
- MeSH
- Acoustic Stimulation methods utilization MeSH
- Animal Experimentation MeSH
- Financing, Organized MeSH
- Haplorhini MeSH
- Electrodes, Implanted utilization MeSH
- Macaca mulatta MeSH
- Meta-Analysis as Topic MeSH
- Cerebral Cortex anatomy & histology physiology MeSH
- Neurons physiology MeSH
- Evoked Potentials, Auditory physiology MeSH
- Auditory Cortex anatomy & histology physiology MeSH
- Statistics as Topic MeSH
- Photic Stimulation methods MeSH
A characteristic of mast cells is the degranulation in response to various stimuli. Here we have investigated the effects of various physical stimuli in the human mast-cell line HMC-1. We have shown that HMC-1 express the transient receptor potential channels TRPV1, TRPV2 and TRPV4. In the whole-cell patchclamp configuration, increasing mechanical stress applied to the mast cell by hydrostatic pressure (–30 to –90 cm H2O applied via the patch pipette) induced a current that could be inhibited by 10 μM of ruthenium red. This current was also inhibited by 20 μM SKF96365, an inhibitor that is among TRPV channels specific for the TRPV2. A characteristic of TRPV2 is its activation by high noxious temperature; temperatures exceeding 50 °C induced a similar ruthenium-red-sensitive current. As another physical stimulus, we applied laser light of 640 nm. Here we have shown for the first time that the application of light (at 48 mW for 20 min) induced an SKF96365-sensitive current. All three physical stimuli that led to activation of SKF96365-sensitive current also induced pronounced degranulation in the mast cells, which could be blocked by ruthenium red or SKF96365. The results suggest that TRPV2 is activated by the three different types of physical stimuli. Activation of TRPV2 allows Ca2+ ions to enter the cell, which in turn will induce degranulation. We, therefore, suggest that TRPV2 plays a key role in mast-cell degranulation in response to mechanical, heat and red laser-light stimulation.
- MeSH
- Cell Line MeSH
- Cell Degranulation MeSH
- Exocytosis MeSH
- TRPV Cation Channels metabolism MeSH
- Humans MeSH
- Mast Cells physiology MeSH
- Patch-Clamp Techniques MeSH
- Check Tag
- Humans MeSH
- Publication type
- Research Support, Non-U.S. Gov't MeSH
Recently, the stimuli-responsive polymers get increased scientific interest due to the ability to reversibly alter their physicochemical properties. They are often referred to as smart, environmental-sensitive or intelligent polymers. This review provides fundamental information on various types of smart polymers responsive to biological, physical and chemical stimuli with examples of their use in the preparation of smart hydrogels and in situ gels with controlled or targeted drug release.
Hippocampal activity is thought to encode spatial representations in a distributed associative network. This idea predicts that partial hippocampal lesions would spare acquisition and impair retrieval of a place response as long as enough connections remained intact to encode associations. Water maze experiments supported the predictions, but the prediction of impaired retrieval was not supported when tetrodotoxin (TTX) was injected into one hippocampus and rats were tested in a place avoidance task on a rotating arena with shallow water. The rotation dissociated relevant distal stimuli from irrelevant self-motion stimuli. To explain the discrepancy, we hypothesized that the segregation of relevant and irrelevant stimuli and stimuli association into representations are distinct hippocampus-dependent operations, and whereas associative representation is more sensitive to disruption during retrieval than learning, stimulus segregation is more sensitive to disruption during learning than during retrieval. The following predictions were tested: (1) the TTX injection would spare learning but (2) impair retrieval of a place response in the water maze, which has a high associative representational demand but a low demand for segregation; (3) the injection would impair learning but (4) spare retrieval of place avoidance in the rotating arena filled with water, which has a high demand for stimulus segregation but a low associative representational demand. All four predictions were confirmed. The hypothesis also explains the pattern of sparing and impairment after the TTX injection in other place avoidance task variants, leading us to conclude that stimulus separation and association representation are dissociable functions of the hippocampus.
- MeSH
- Analysis of Variance MeSH
- Anesthetics, Local toxicity MeSH
- Maze Learning physiology drug effects MeSH
- Time Factors MeSH
- Behavior, Animal MeSH
- Financing, Organized MeSH
- Hippocampus physiology drug effects injuries MeSH
- Rats MeSH
- Memory Disorders physiopathology MeSH
- Rats, Long-Evans MeSH
- Mental Recall physiology drug effects MeSH
- Tetrodotoxin toxicity MeSH
- Avoidance Learning physiology drug effects MeSH
- Escape Reaction physiology drug effects MeSH
- Space Perception physiology drug effects MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Comparative Study MeSH
