Consciousness and loss of consciousness is something we encounter in our everyday lives. Despite its commonplace in everyday life, scientists are still trying to understand and find reliable markers for it. In this work we use a data-driven K-means clustering approach to uncover the different functional patterns associated with different consciousness levels. We pursue this study using a high resolution optogenetic voltage image of the mouse brain waking up from anesthesia. The main questions we addressed in this study are: Can we identify signatures of conscious and unconsciousness from functional connectivity patterns? What is the nature of the different patterns that correspond to wakefulness and anesthesia? What is the nature of dynamics between these functional patterns in wakefulness and anesthesia? How does the anatomical connectivity support the observed functional patterns in wakefulness and anesthesia? Our results show that during anesthesia, the brain is characterized by a single dominant brain pattern with short range connections. Furthermore, we observed from our results that during anaesthesia the brain is characterized by minimal temporal exploration of the different brain configurations. Conversely, in awake state we observed the opposite. The brain pattern with long range connections are frequent in wakefulness. In addition, wakefulness is characterized by somewhat frequent temporal exploration of brain states. Our results show that analysis of functional connectivity patterns can be a useful tool for identifying specific and generalizable fingerprints of wakefulness and anaesthesia

Colored photographs included. / Thesis (M.Sc.D.)--Boston University. Henry M. Goldman School of Graduate Dentistry, 1983 (Endodontics) / Bibliography: leaves 59-63. / Profound anesthesia is of paramount importance to the endodontist when treating vital cases. Many a clinician has experienced the frustration of attempting root canal therapy upon an inadequately-anesthetized “hot” mandibular tooth. Consequently, many different methods of anesthetizing lower teeth have been proposed, including; 1. Mandibular block with a lingual supplementary injection as described by Schilder[1] 2. Periodontal ligament injection devices[2,3,4] 3. Gow Gates[5-9] 4. Akinosi[10] 5. Intraosseous[11] 6. Interseptal[12] This project　studied the efficacy of the first　two methods in delivering mandibular anesthesia for endodontic purposes.　Its main objective was　to answer the question of whether an instrument such as the Ligmaject[tm] is a beneficial　addition　to　the endodontic armamentarium. Questionaires were completed by graduate endodontic students at B.U.S.G.D. 50 teeth were anesthetized using a mandibular block and lingual　supplemental injection. 63 teeth were anesthetized using the Ligmaject[tm]. Results demonstrated that the Ligmaject[tm]; 1.　Yielded faster onset　of anesthesia. 2. Provided shorter duration of anesthesia (30 min. to one hour) than the mandibular block (2-4 hours). 3. Was generally more comfortable for patients than the mandibular block.　However, the PDL-injection was extremely painful for some patients. 4. Was　less reliable　than　the mandibular block and lingual　supplemental in rendering vital mandibular teeth　totally numb. A large number Of PDL-injected teeth needed mandibular blocks in order to obtain access for the intrapulpal injections. This required additional manipulations of the patients. 5. Should not be used on undebrided areas or teeth with suppurative periodontal 1esions. 6. Has the potential for initiating periodontal damage even on healthy periodontiums as demonstrated by a case report　documented with preoperative and postoperative radiographs and photos. Preservation of the attachment　apparatus is a critical element　of any dental　discipline. Despite its advantage of shorter anesthetic duration, the use of the Ligmaject[tm] does not　seem consistent with this philosophy.

Introduction Maternal volume depletion at the time of caesarean section plays a role in ma- ternal and fetal outcome. Measuring uid volume status currently requires invasive monitors. It would be useful to determine biochemical measurements which would accurately determine uid volume status in these patients. We investigated the di erence in biochemical parameters of participants presenting for elective and urgent caesarean section at Chris Hani Baragwanath Hospital and made inferences about their uid volume status. We also sought to de- termine whether this difference in biochemical parameters if present could be linked to a potential difference in the intra-operative haemodynamic course as well as fetal outcome between the two groups. Method This was a prospective open-label observational cross-sectional pilot study. The sample was 54 participants, 27 elective and 27 urgent cases. Blood and urine samples were taken at the red line. Parameters from the blood samples were haematocrit, haemoglobin, sodium, urea, creatinine and plasma osmolality. Parameters from the urine samples were sodium, creatinine, osmolality and specific gravity. Intra-operatively, all participants received a standard spinal anaesthetic. Vari- ables measured intra-operatively were systolic, diastolic and mean arterial blood pressure, heart rate, highest level of block achieved as well as 1 and 5 minute Apgar scores of the newborn. The primary outcome variable was hypotension (mean arterial drop of more than 15% from the baseline). The secondary outcome variable were the Apgar scores of the infants. Results Urine specific gravity showed a trend towards statistical significance (mean, median, standard deviation for elective, urgent): 1.01, 1.010, 0.01 and 1.02, 1.015, 0.01 p = 0:06. The other biochemical parameteres displayed higher p- values. The average relative blood pressure change was -11,7% (median, standard de- viation) (-12.4, 11.1) for the elective group and -15.1% (-14.9, 15.1) for the urgent group p = 0:36. The relative blood pressure change to end point of study was -9.6% (-9, 12.7) for the elective group and -15.4% (-17, 17.6) for the urgent group p = 0:17. When comparing baseline blood pressure and heart rate measurements to the 10 minute end point measurements; 15 participants expe- rienced hypotension in the urgent group compared to 9 in the elective group p = 0:17. When comparing baseline blood pressure measurements to the av- erage at 2, 4, 6, 8, and 10 minute intervals; 13 participants from the urgent group experienced hypotension compared to 9 participants in the elective group p = 0:40. The average Apgar scores at 1 min were 8.89 (9,0.32) for the elective group and 8.37 (9,0.93) for the urgent group p = 0:01. Conclusion This was a pilot study and as such statistical signi cance between variables was not expected. However possible trends were identified to guide future investiga- tions. The higher incidence rate of hypotension in the urgent group showed such a trend towards signi cance as well as the higher urine specific gravity in the urgent group. We also noted that Apgar scores differed significantly between elective and urgent cases.

Indiana University-Purdue University Indianapolis (IUPUI) / The need for a safe but effective agent to sedate dental patients who are severe behavior management problems prompted this investigation of ketamine HCl. Ketamine HCl is a general anesthetic agent with the unique property of selectively depressing the higher centers of the brain without adversely affecting respiration or cardiac output. Sixty behavior problem pedodontic patients were selected at random and placed in one of three groups to receive the following treatments: Treatment I - ketamine HCl and scopolamine; Treatment II - ketamine, scopolamine, and droperidol, and Treatment III - ketamine, scopolamine, and nitrous oxide-oxygen analgesia. Each treatment group received ketamine HCl 2 mg/lb and 0.1 - 0.3 mg scopolamine. The second two treatment groups were supplemented with droperidol .025 mg/lb or nitrous oxide-oxygen (20-50%) to maintain anesthesia. The patients were given a series of pre and post-treatment mental and physical tests and were considered completely recovered when they could equal their pre treatment test scores. Routine dental restorative procedures limited to one and one-half hours were carried out with the use of the ruber dam. Onset of anesthesia was five minutes for all three treatment groups. Treatment III showed a significantly longer working time but recovery times were not significantly different between groups. Ketamine HCl was determined to be a safe, effective agent for use in pedodontic outpatients provided prescribed techniques are followed. Complications were infrequent and minor and parental response was considered satisfactory.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

No description available.

No description available.

No description available.

published_or_final_version / Dentistry / Master / Master of Dental Surgery

Despite the advances made in our understanding of the molecular mechanistic actions of general anesthetics very little is known about the in vivo neural circuits involved in creating the state of general anesthesia. To date the common consensus is that general anesthetics act ubiquitously within the CNS. Recently, (Devor and Zalkind, 2001) have reported that microinjections of pentobarbital (PB) into a discrete brainstem focal area of conscious rats induced a classical, reversible general anesthesia-like behavioral state. The authors concluded that this area, termed the mesopontine tegmental anesthesia area (MPTA), may be important for the induction of general anesthesia. The purpose of the present project was to study the neurophysiological basis of the analgesia, which accompanied the state of general anesthesia induced by PB microinjections into the MPTA that was reported by (Devor and Zalkind, 2001). Here, sensory inflow via the spinothalamic tract (STT), a classical spinal nociceptive pathway in the rat, was assessed using single neuron extracellular recording techniques before, during and after microinjections of PB into the MPTA. Spontaneous firing rate (SFR), antidromic firing index (FI) and sciatic as well as sural nerve-evoked responses (Sc-, Su-ER) of STT neurons in isoflurane-anesthetized rats were quantified before as well as 2, 15, 30 and 60 min following bilateral microinjections of either PB (200 micrograms/side) or vehicle control solution (Vh, 1 microliter/side) into the MPTA. The group mean SFR, FI as well as magnitudes of Sc-, Su-ER of STT neurons were significantly and reversibly reduced following PB microinjections compared to corresponding baseline measurements. There were no significant changes in any of the three parameters following microinjections of Vh compared to the pre-microinjection baseline responses. The results from this study indicate that analgesia, which occurs during the anesthesia-like state following microinjections of PB into the MPTA, may be due to attenuation of sensory inflow through the STT. The suppression of STT neurons likely occurs via direct and/or indirect descending pathways from the MPTA to the spinal cord. This study provides the first direct electrophysiological evidence for the analgesia caused by PB microinjections into the rat MPTA.