A COMPARATIVE ANALYSIS FOR REDUCTION OF POST-SURGICAL SORE THROAT BY APPLYING OF KETAMINE-NEBULIZATION & BETAMETHASONE-GEL OVER THE ENDO-TRACHEAL TUBE CUFF

Background: In general anaesthesia (GA), endo-tracheal -intubation is required to control respiration & to protect the airway. The commonest locations of injury while intubation are the larynx & trachea, which typically manifest as regional pain, inflammation & even necrosis. Aims & objectives: This research was carried out to contrast the efficaciousness of ketamine-nebulization & betamethasone-gel on the cuff of the endo-tracheal -tube to alleviate post-surgical throat pain (POST). Materials & methods: This is a randomized, prospective research assessing the efficaciousness of betamethasone-gel & lignocaine-jelly ketamine-nebulisation applied over the endo-tracheal -tube cuff to decrease post-surgical sore throat nebulisation (POST). The study subjects were divided randomly into ketamine (category K), betamethasone (category B) & lignocaine category (category L). Study subjects were observed immediately after extubation (0 hr), 2 hrs, 6 hrs, 12 hrs & 24 hours after the post-surgical time for POST, which was rated on a four-point ranking. Results: In this research, the total occurrence of POST was 30 %. Out of this, POST occurred only in 20 % of study subjects in the (K) category, 23 % of study subjects in the (B) category, contrasted to 47% in the (L) (control) category. The occurrence of POST at 0 hr, 2 hrs, 6 hrs, 12 hrs, 24 hours was 10 %, 10 %, 17 %, 10 % & 7 % respectively in the ketamine-nebulisation category. Conclusion: This research culminates that pre-surgical nebulization with ketamine & betamethasone-gel applied over the cuff of the endo-tracheal -tube is equally successful in reducing POST. Key Word: ketamine-nebulization, betamethasone-gel, lignocaine, Endo-tracheal -intubation

The Respiratory Resistance Sensitivity Task: An Automated Method for Quantifying Respiratory Interoception and Metacognition

The ability to sense, monitor, and control respiration - e.g., respiratory interoception (henceforth, respiroception) is a core homeostatic ability. Beyond the mere regulation of gas exchange, enhanced awareness of respiratory sensations is directly related to psychiatric symptoms such as panic and anxiety. Indeed, chronic breathlessness (dyspnea) is associated with a fourfold increase in the risk of developing depression and anxiety, and the regulation of the breath is a key aspect of many mindfulness-based approaches to the treatment of mental illness. Physiologically speaking, the ability to accurately monitor respiratory sensations is important for optimizing cardiorespiratory function during athletic exertion, and can be a key indicator of illness. Given the important role of respiroception in mental and physical health, it is unsurprising that there is increased interest in the quantification of respiratory psychophysiology across different perceptual and metacognitive levels of the psychological hierarchy. Compared to other more popular modalities of interoception, such as in the cardiac domain, there are relatively few methods available for measuring aspects of respiroception. Existing inspiratory loading tasks are difficult to administer and frequently require expensive medical equipment, or offer poor granularity in their quantification of respiratory-related perceptual ability. To facilitate the study of respiroception, we here present a new, fully automated and computer-controlled apparatus and psychophysiological method, which can flexibly and easily measure respiratory-related interoceptive sensitivity, bias and metacognition, in as little as 30 minutes of testing, using easy to make 3D printable parts.

Characterization of a novel type of carbonic anhydrase that acts without metal cofactors

Background Carbonic anhydrases (CAs) are universal metalloenzymes that catalyze the reversible conversion of carbon dioxide (CO2) and bicarbonate (HCO3-). They are involved in various biological processes, including pH control, respiration, and photosynthesis. To date, eight evolutionarily unrelated classes of CA families (α, β, γ, δ, ζ, η, θ, and ι) have been identified. All are characterized by an active site accommodating the binding of a metal cofactor, which is assumed to play a central role in catalysis. This feature is thought to be the result of convergent evolution. Results Here, we report that a previously uncharacterized protein group, named “COG4337,” constitutes metal-independent CAs from the newly discovered ι-class. Genes coding for COG4337 proteins are found in various bacteria and photosynthetic eukaryotic algae. Biochemical assays demonstrated that recombinant COG4337 proteins from a cyanobacterium (Anabaena sp. PCC7120) and a chlorarachniophyte alga (Bigelowiella natans) accelerated CO2 hydration. Unexpectedly, these proteins exhibited their activity under metal-free conditions. Based on X-ray crystallography and point mutation analysis, we identified a metal-free active site within the cone-shaped α+β barrel structure. Furthermore, subcellular localization experiments revealed that COG4337 proteins are targeted into plastids and mitochondria of B. natans, implicating their involvement in CO2 metabolism in these organelles. Conclusions COG4337 proteins shared a short sequence motif and overall structure with ι-class CAs, whereas they were characterized by metal independence, unlike any known CAs. Therefore, COG4337 proteins could be treated as a variant type of ι-class CAs. Our findings suggested that this novel type of ι-CAs can function even in metal-poor environments (e.g., the open ocean) without competition with other metalloproteins for trace metals. Considering the widespread prevalence of ι-CAs across microalgae, this class of CAs may play a role in the global carbon cycle.

Caffeine reverses the unconsciousness produced by light anesthesia in the continued presence of isoflurane in rats

Currently no drugs are employed clinically to reverse the unconsciousness induced by general anesthetics. Our previous studies showed that caffeine, when given near the end of an anesthesia session, accelerated emergence from isoflurane anesthesia, likely caused by caffeine’s ability to elevate intracellular cAMP levels and to block adenosine receptors. These earlier studies showed that caffeine did not rouse either rats or humans from deep anesthesia (≥ 1 minimum alveolar concentration, MAC). In this current crossover study, we examined whether caffeine reversed the unconsciousness produced by light anesthesia (< 1 MAC) in the continued presence of isoflurane. The primary endpoint of this study was to measure isoflurane levels at the time of recovery of righting reflex, which was a proxy for consciousness. Rats were deeply anesthetized with 2% isoflurane (~1.5 MAC) for 20 minutes. Subsequently, isoflurane was reduced to 1.2% for 10 minutes, then by 0.2% every 10 min; animals were monitored until the recovery of righting reflex occurred, in the continued presence of isoflurane. Respiration rate, heart rate and electroencephalogram (EEG) were monitored. Our results show that caffeine-treated rats recovered their righting reflex at a significantly higher inspired isoflurane concentration, corresponding to light anesthesia, than the same rats treated with saline (control). Respiration rate and heart rate increased initially after caffeine injection but were then unchanged for the rest of the anesthesia session. Deep anesthesia is correlated with burst suppression in EEG recordings. Our data showed that caffeine transiently reduced the burst suppression time produced by deep anesthesia, suggesting that caffeine altered neuronal circuit function but not to a point where it caused arousal. In contrast, under light anesthesia, caffeine shifted the EEG power to high frequency beta and gamma bands. These data suggest that caffeine may represent a clinically viable drug to reverse the unconsciousness produced by light anesthesia.

Phasic inhibition as a mechanism for generation of rapid respiratory rhythms

Central neural networks operate continuously throughout life to control respiration, yet mechanisms regulating ventilatory frequency are poorly understood. Inspiration is generated by the pre-Bötzinger complex of the ventrolateral medulla, where it is thought that excitation increases inspiratory frequency and inhibition causes apnea. To test this model, we used an in vitro optogenetic approach to stimulate select populations of hindbrain neurons and characterize how they modulate frequency. Unexpectedly, we found that inhibition was required for increases in frequency caused by stimulation of Phox2b-lineage, putative CO2-chemosensitive neurons. As a mechanistic explanation for inhibition-dependent increases in frequency, we found that phasic stimulation of inhibitory neurons can increase inspiratory frequency via postinhibitory rebound. We present evidence that Phox2b-mediated increases in frequency are caused by rebound excitation following an inhibitory synaptic volley relayed by expiration. Thus, although it is widely thought that inhibition between inspiration and expiration simply prevents activity in the antagonistic phase, we instead propose a model whereby inhibitory coupling via postinhibitory rebound excitation actually generates fast modes of inspiration.

Microbial characteristics, carbon and nitrogen content in cambisols and luvisols

Tested soils (1991&ndash;2002) were defined by chemical, textural and microbial characteristics. From the tests which describe cambisols, the following parameters have to be stressed. The higher level of C_org (1.20&ndash;1.76%), which resulted in quite high microbial biomass carbon content (396&ndash;625 &micro;g/g dry soil), high control respiration (0.45&ndash;0.80 mg CO₂/h/100 g dry soil) and potential nitrification with (NH₄)₂SO₄ (6.7&ndash;18.4 mg N-NO₃/8 days/100 g dry soil). Studied luvisols reached typical levels: C_org (0.97&ndash;1.22%), C_MB (398&ndash;503 &micro;g/g dry soil), control respiration (0.46&ndash;0.57 mg CO₂/h/100 g dry soil), potential nitrification with (NH₄)₂SO₄ (3.2&ndash;9.9 mg N-NO₃/8 days/100 g dry soil). Lower levels of organic carbon and a medium level of microbial biomass raised in higher ratio C_MB/C_org(average 4.0%). Highly significant differences (p &lt; 0.01) between cambisols and luvisols were determined for C_org, N_t, pH(KCl), C_MB, C_MB/C_org, C_E, control respiration and potential nitrification, while the difference in potential ammonification with peptone was at level p &lt; 0.05. With the exemption of ratio C_MB/C_org all cambisol characteristics were higher than luvisol ones. Studied soils were evaluated by six biological criteria (C_MB; ratios: C_MB/C_org, C_E/C_MB, potential/control respiration, potential/control ammonification, potential/control nitrification). These criteria distinguished tested soils into three groups. The first one includes two localities in the mountain region (Červen&aacute; Voda 809, 810; altitude 565&ndash;590 m) defined as stagnic cambisols with higher content of C_org (1.40, respective 1.76%) and simultaneously with the highest biomass of micro-organisms from all tested soils (C_MB,625, respective 621 &micro;g/g dry soil). It is not surprising that microbial activities (respiration, nitrification) at these localities were also high. The majority of the studied localities (one eutric cambisol and four luvisols) belongs to the medium group. The third group includes two localities (Neumětely &ndash; haplic luvisol, Čist&aacute; u Rakovn&iacute;ka &ndash; eutric cambisol) where biological criteria was mostly the worst. In the period 1993&ndash;2002 microbial biomass carbon was for both sites in the range of 357&ndash;458 &micro;g/g dry soil which are not so bad values, but in comparison with localities in mountain wet region they are low. This status was issued in the lower ratio C_MB/C_org (2.71&ndash;3.77%).