A Novel Potential Treatment for Diabetic Foot Ulcers and Non-Healing Ulcers - Case Series.

INTRODUCTION: Appropriate care and treatment of a wound is the need of the hour whether it is an infected or a non-infected wound. If wound healing is delayed for some reason, it leads to serious complications and further increases the hospital stay and cost of treatment. Herein, we describe a novel antimicrobial wound dressing formulation (VG111), with an objective to generate the preliminary data showing the distinct advantages in various types of wounds. METHOD: This case series involved the treatment of acute cases of wounds or chronic wounds that did not respond well to conventional wound healing treatments with VG111 in patients with different etiologies. Thirteen cases of patients that included patients with diabetes, pressure ulcers, burns, trauma, and others treated with VG111 showed rapid wound healing in all the cases, even obviating the need for a graft when complete skin regeneration occurred RESULT: This was illustrated by clearing of the wound infections, reduction/disappearance of the exudate, appearance of intense granulation, epithelialization, and anti-biofilm activity followed by complete wound closure. This VG111 precludes the need for systemic antimicrobial agents in localized infections and therefore, this single agent is an attempt to address the limitations and the drawbacks of the available products. CONCLUSION: Despite patients belonging to the old age group and having comorbidities like diabetes, still VG111 showed effective rapid wound healing, and that too without any scar formation in hardto-heal, infected, and non-infected wounds

Sleep alterations in mammals: did aquatic conditions inhibit rapid eye movement sleep?

Sleep has been studied widely in mammals and to some extent in other vertebrates. Higher vertebrates such as birds and mammals have evolved an inimitable rapid eye movement (REM) sleep state. During REM sleep, postural muscles become atonic and the temperature regulating machinery remains suspended. Although REM sleep is present in almost all the terrestrial mammals, the aquatic mammals have either radically reduced or completely eliminated REM sleep. Further, we found a significant negative correlation between REM sleep and the adaptation of the organism to live on land or in water. The amount of REM sleep is highest in terrestrial mammals, significantly reduced in semi-aquatic mammals and completely absent or negligible in aquatic mammals. The aquatic mammals are obligate swimmers and have to surface at regular intervals for air. Also, these animals live in thermally challenging environments, where the conductive heat loss is approximately ~90 times greater than air. Therefore, they have to be moving most of the time. As an adaptation, they have evolved unihemispheric sleep, during which they can rove as well as rest. A condition that immobilizes muscle activity and suspends the thermoregulatory machinery, as happens during REM sleep, is not suitable for these animals. It is possible that, in accord with Darwin's theory, aquatic mammals might have abolished REM sleep with time. In this review, we discuss the possibility of the intrinsic role of aquatic conditions in the elimination of REM sleep in the aquatic mammals.

A Moderate Increase of Physiological CO(2) in a Critical Range during Stable NREM Sleep Episode: A Potential Gateway to REM Sleep.

Sleep is characterized as rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Studies suggest that wake-related neurons in the basal forebrain, posterior hypothalamus and brainstem, and NREM sleep-related neurons in the anterior-hypothalamic area inhibit each other, thus alternating sleep-wakefulness. Similarly, pontine REM-ON and REM-OFF neurons reciprocally inhibit each other for REM sleep modulation. It has been proposed that inhibition of locus coeruleus (LC) REM-OFF neurons is pre-requisite for REM sleep genesis, but it remains ambiguous how REM-OFF neurons are hyperpolarized at REM sleep onset. The frequency of breathing pattern remains high during wake, slows down during NREM sleep but further escalates during REM sleep. As a result, brain CO(2) level increases during NREM sleep, which may alter REM sleep manifestation. It has been reported that hypocapnia decreases REM sleep while hypercapnia increases REM sleep periods. The groups of brainstem chemosensory neurons, including those present in LC, sense the alteration in CO(2) level and respond accordingly. For example, one group of LC neurons depolarize while other hyperpolarize during hypercapnia. In another group, hypercapnia initially depolarizes but later hyperpolarizes LC neurons. Besides chemosensory functions, LC REM-OFF neurons are an integral part of REM sleep executive machinery. We reason that increased CO(2) level during a stable NREM sleep period may hyperpolarize LC neurons including REM-OFF, which may help initiate REM sleep. We propose that REM sleep might act as a sentinel to help maintain normal CO(2) level for unperturbed sleep.

Fear conditioning fragments REM sleep in stress-sensitive Wistar-Kyoto, but not Wistar, rats.

Pavlovian conditioning is commonly used to investigate the mechanisms of fear learning. Because the Wistar-Kyoto (WKY) rat strain is particularly stress-sensitive, we investigated the effects of a psychological stressor on sleep in WKY compared to Wistar (WIS) rats. Male WKY and WIS rats were either fear-conditioned to tone cues or received electric foot shocks alone. In the fear-conditioning procedure, animals were exposed to 10 tones (800 Hz, 90 dB, 5s), each co-terminating with a foot shock (1.0 mA, 0.5s), at 30-s intervals. In the shock stress procedure, animals received 10 foot shocks at 30-s intervals, without tones. All subjects underwent a tone-only test both 24h (Day 1) and again two weeks (Day 14) later. Rapid eye movement sleep (REMS) continuity was investigated by partitioning REMS episodes into single (inter-REMS episode interval >3 min) and sequential (interval ≤ 3 min) episodes. In the fear-conditioned group, freezing increased from baseline in both strains, but the increase was maintained on Day 14 in WKY rats only. In fear-conditioned WKY rats, total REMS amount increased on Day 1, sequential REMS amount increased on Day 1 and Day 14, and single REMS amount decreased on Day 14. Alterations were due to changes in the number of sequential and single REMS episodes. Shock stress had no significant effect on REMS microarchitecture in either strain. The shift toward sequential REMS in fear-conditioned WKY rats may represent REMS fragmentation, and may provide a model for investigating the neurobiological mechanisms of sleep disturbances reported in posttraumatic stress disorder.

Long-term effect of cued fear conditioning on REM sleep microarchitecture in rats.

STUDY OBJECTIVES: To study long-term effects of conditioned fear on REM sleep (REMS) parameters in albino rats. DESIGN: We have investigated disturbances in sleep architecture, including muscle twitch density as REMS phasic activity, and freezing behavior in wakefulness, upon reexposure to a conditioned stimulus (CS) on Day 1 and Day 14 postconditioning. SUBJECTS: Male Sprague-Dawley rats prepared for polysomnographic recordings. INTERVENTIONS: After baseline sleep recording, the animals in the experimental group received five pairings of a 5-sec tone, co-terminating with a 1-sec, 1 mAfootshock. The control rats received similar numbers of tones and shocks, but explicitly unpaired. On postconditioning days, after reexposure to tones alone, sleep and freezing behavior were recorded. MEASUREMENTS AND RESULTS: Conditioned fear significantly altered REMS microarchitecture (characterized as sequential-REMS [seq-REMS: < or =3 min episode separation] and single-REMS [sin-REMS: >3 min episode separation]) on Day 14. The total amount and number of seq-REMS episodes decreased, while the total amount and number of sin-REMS episodes increased. Further, the CS induced significant increases in freezing and REMS myoclonic twitch density in the experimental group. Reexposure to the CS produced no alterations in controls. CONCLUSIONS: The results suggest that conditioned fear causes REMS alterations, including difficulty in initiating a REMS episode as indicated by the diminution in the number of seq-REMS episodes. Another finding, the increase in phasic activity, agrees with the inference from clinical investigations that retrieval of fearful memories can be associated with the long-term REMS disturbances characteristic of posttraumatic stress disorder.

Neural mechanism of rapid eye movement sleep generation: Cessation of locus coeruleus neurons is a necessity.

Two types of neurons are involved in the regulation of rapid eye movement (REM) sleep, the REM-ON and the REM-OFF neurons. As the name suggests, the REM-OFF neurons cease firing during REM sleep and they are norepinephrinergic. It has been shown that cessation of these neurons is a pre-requisite for the generation of REM sleep and GABA shuts them off. Further, if these neurons do not shut off, there is increased levels of norepinephrine in the brain and loss of REM sleep. The REM sleep deprivation induced increase in norepinephrine is responsible for mediating at least REM sleep loss induced increase in Na(+)-K(+) ATPase activity, which is likely to be the primary factor for causing REM sleep deprivation induced effects.

Long term blocking of GABA-A receptor in locus coeruleus by bilateral microinfusion of picrotoxin reduced rapid eye movement sleep and increased brain Na-K ATPase activity in freely moving normally behaving rats.

Isolated studies showed that norepinephrinergic REM-OFF neurons are active throughout except during rapid eye movement (REM) sleep when they are inhibited possibly by GABA. Similarly, independent studies have also reported that during REM sleep deprivation those REM-OFF neurons continue firing, that there is increased norepinephrine (NE) in the brain and that increased levels of NE increases the Na-K ATPase activity in the brain. However, it was not known if all those changes were directly related to REM sleep deprivation, what could be the mechanism for such changes and their patho-physiological significance. To confirm the same, based on the reports, mostly from our group, it was hypothesised that GABA antagonist in the locus coeruleus (LC) should at least significantly reduce REM sleep and simultaneously increase Na-K ATPase activity in the brain. To confirm the proposed hypothesis, picrotoxin, a GABA-A receptor antagonist, was bilaterally microinjected every 6 h for 36 h into the LC of freely moving normally behaving rats and the effects on electrophysiological signals signifying sleep-wakefulness and on brain synaptosome Na-K ATPase activity were estimated. The microinjection was done with the help of a remote control pump without handling or disturbing the rats. The findings that REM sleep was significantly reduced and there was associated increase in Na-K ATPase activity confirmed our hypothesis. The results also support our modified (GABA-mediated) model of neural connections in the LC for the regulation of REM sleep. Also, this is probably the first report to simulate REM sleep deprivation using receptor antagonist.

Increased turnover of Na-K ATPase molecules in rat brain after rapid eye movement sleep deprivation.

It has been shown that rapid eye movement (REM) sleep deprivation increases Na-K ATPase activity. Based on kinetic study, it was proposed that increased activity was due to enhanced turnover of enzyme molecules. To test this, anti-alpha1 Na-K ATPase monoclonal antibody (mAb 9A7) was used to label Na-K ATPase molecules. These labeled enzymes were quantified on neuronal membrane by two methods: histochemically on neurons in tissue sections from different brain areas, and by Western blot analysis in control and REM sleep-deprived rat brains. The specific enzyme activity was also estimated and found to be increased, as in previous studies. The results confirmed our hypothesis that after REM sleep deprivation, increased Na-K ATPase activity was at least partly due to increased turnover of Na-K ATPase molecules in the rat brain.

Role of norepinephrine in the regulation of rapid eye movement sleep.

Sleep and wakefulness are instinctive behaviours that are present across the animal species. Rapid eye movement (REM) sleep is a unique biological phenomenon expressed during sleep. It evolved about 300 million years ago and is noticed in the more evolved animal species. Although it has been objectively identified in its present characteristic form about half a century ago, the mechanics of how REM is generated, and what happens upon its loss are not known. Nevertheless, extensive research has shown that norepinephrine plays a crucial role in its regulation. The present knowledge that has been reviewed in this manuscript suggests that neurons in the brain stem are responsible for controlling this state and presence of excess norepinephrine in the brain does not allow its generation. Furthermore, REM sleep loss increases levels of norepinephrine in the brain that affects several factors including an increase in Na-K ATPase activity. It has been argued that such increased norepinephrine is ultimately responsible for REM sleep deprivation, associated disturbances in at least some of the physiological conditions leading to alteration in behavioural expression and settling into pathological conditions.