Laser induced autofluorescence studies of animal skin used in modeling of human cutaneous tissue spectroscopic measurements

BACKGROUND/PURPOSE: Laser-induced autofluorescence spectroscopy provides excellent possibilities for medical diagnostics of different tissue pathologies including cancer. However, to create the whole picture of pathological changes, investigators collect spectral information from patients in vivo or they study different tumor models to obtain objective information for fluorescent properties of every kind of healthy and diseased tissue. Therefore, it is very important to find the most appropriate, and close to the human skin, animal samples from the fluorescence point of view, which will allow the extrapolation of the animal data to human spectroscopic diagnostics. METHODS: In the present work, we examined the autofluorescence properties of different animal skin tissues, which are considered as the most common skin models. A nitrogen laser was used as an excitation source. Samples of healthy mouse, chicken and pig skin in vivo and/or ex vivo were studied and were compared with results obtained from investigations of healthy human skin in vivo. RESULTS AND CONCLUSION: Specific features of the recorded spectra are discussed and the possible origin of the obtained fluorescence signals is proposed. Quantitative evaluation of data extrapolation for each skin type is also depicted.     

Effects of different speeds of induction with sevoflurane on the EEG in Man

The effects of two kinds of induction speed of sevoflurane anesthesia on the EEG pattern were compared in the same individual using medical student volunteers: a first exposure of 4% was given, followed after full recovery, by incremental doses of 1, 2 and 4% successively, each being administered for 10min. The arterial blood level of the anesthetic was measured using gaschromatograph. The changes of EEG pattern during fast induction with 4% were not represented by the abbreviation of those observed during the slow induction with the incremental doses. The administration of 4% induced a sudden appearance of high voltage, rhythmic slow waves of 2–3Hz at 1–3min when the arterial blood anesthetic level increased maximally, which was then followed by a pattern of faster activities of 10–14Hz mixed with 5–8Hz slow waves. In contrast, the administration of incremental doses induced an increase in frequency and amplitude of EEG activities in the light plane, followed by their decreases in deeper planes. The final EEG patterns were identical for both these methods of induction. These findings confirmed our previous hypothesis that not only the arterial blood level of anesthetics but the rate of its increase are important factors determining the EEG pattern of anesthesia.(Avramov MN et al.: Effects of different speeds of induction with sevoflurane on the EEG in man. J Anesth 1: 1–7, 1987)     

The use of a ketamine-propofol combination during monitored anesthesia care

Supplemental analgesics are commonly used to enhance analgesia and improve patient comfort during procedures performed under local anesthesia and sedation. Because the use of ketamine as an analgesic adjunct to propofol sedation has not been well established, we evaluated its impact on analgesia, sedation, and recovery after ambulatory surgery. One hundred female outpatients undergoing breast biopsy procedures under local anesthesia participated in this randomized, double-blinded, placebo-controlled study. After premedication with midazolam, 2 mg IV, patients received an infusion of a solution containing propofol (9.4 mg/mL) in combination with either placebo (saline) (Group 1) or ketamine, 0.94 mg/mL (Group 2), 1.88 mg/mL (Group 3), or 2.83 mg/mL (Group 4). The sedative infusion rate was varied to maintain a deep level of sedation (Observer Assessment of Alertness/Sedation score 4) and normal respiratory and hemodynamic functions. Sufentanil, 2.5 microg IV, "rescue" boluses were used as needed to treat patients' responses (if any) to local anesthetic infiltration or surgical stimulation. Ketamine produced a dose-dependent reduction in the "rescue" opioid requirements. However, there was an increase in postoperative nausea and vomiting, psychomimetic side effects, and delay in discharge times with the largest ketamine dosage (Group 4). The adjunctive use of ketamine during propofol sedation provides significant analgesia and minimizes the need for supplemental opioids. The combination of propofol (9.4 mg/mL)/ketamine (0.94-1.88 mg/mL) provides effective sedation/analgesia during monitored anesthesia care. IMPLICATIONS: Ketamine, when used in subhypnotic dosages, may be an useful adjuvant to propofol sedation.     

Progressive changes in electroencephalographic responses to nitrous oxide in humans: a possible acute drug tolerance

The possibility of acute tolerance to nitrous oxide was examined during halothane anesthesia in humans. Nitrous oxide was added to the inspired gas twice. The first admixture induced three successive stages of electroencephalogram (EEG): delta-waves lasting for 13 +/- 12 min, theta-waves lasting for 41 +/- 21 min, and, finally, spindle-type waves. The spindle-type EEG was similar to that of halothane anesthesia in configuration, but smaller in amplitude and faster in frequency than that seen during halothane anesthesia. The second admixture, given after a 20-30-min interval, induced a continuous delta-wave EEG in one patient, theta-waves followed by spindle EEG in eight patients, and spindle-type EEG in four patients. The successive changes of electroencephalographic response during the first admixture indicate that an alteration of central nervous system function occurred. The altered state was maintained in the absence of nitrous oxide: responses to a second admixture were characteristic of the later, altered, stages of responses seen after the first admixture. These findings support the view of acute tolerance to nitrous oxide.     

Transient cortical blindness following vertebral angiography in a young adult with cerebellar haemangioblastoma

Transient cortical blindness is reported to occur in 0.3% to 1% of cerebral angiography procedures. It develops within minutes of contrast medium injection and lasts for up to several days. We report a long episode of transient cortical blindness in a 17-year-old boy with cerebellar haemangioblastoma, which started during the preoperative vertebral angiography and lasted for 5 days. CT performed 2 days after the sudden onset of bilateral visual loss showed multiple asymmetrical lesions within the brain parenchyma in the distribution of the posterior cerebral circulation. Even though the patient’s vision was completely restored 5 days after angiography, repeat MRI performed 2 months after angiography showed improvement but with residual lesions in the thalami, cerebellum and occipital lobe.     

Minor impairment of oral iron absorption in non-diabetic new dialysis patients

BACKGROUND: Iron absorption is impaired in end-stage renal disease (ESRD). ESRD duration and diabetes mellitus (DM) are prominent risk factors in ESRD patients, associated with multi-system complications involving the gastrointestinal tract. Therefore, we suggest that DM and ESRD duration contribute to iron absorption impairment in ESRD. Since we administer oral iron during hemodialysis (HD) sessions, we assessed the relationship of DM and ESRD duration to intradialytic iron absorption. METHODS: A 4-hr intradialytic oral iron absorption test was performed in 22 non-diabetic patients and 21 diabetic chronic HD patients. Elemental iron, 100 mg (iron(III)-hydroxide-polymaltose) was administered at dialysis start. Serum iron levels were measured hourly since iron ingestion, and standardized according to transferrin levels to correct for intradialytic blood volume changes. The primary end point was peak increase in standardized serum iron level (DeltaI). ESRD duration and DM were defined as months on dialysis and the presence of DM before dialysis initiation, respectively. Evaluated confounding factors included age, gender, dry weight (DW), ultrafiltration volume (UF), UF/DW, eKt/V, transferrin saturation (%SAT), ferritin, parathyroid hormone (PTH), C-reactive protein (CRP) and erythropoietin (EPO) dosage. RESULTS: DeltaI was significantly inversely correlated with ESRD duration. DM was significantly associated with lower DeltaI after statistically controlling for ESRD duration. These relationships remained significant after statistically controlling for %SAT, UF and UF/DW. %SAT was significantly inversely correlated with DeltaI, but contributed to lower variability of DeltaI (11%) than DM (15.2%) and ESRD duration (16.5%). CONCLUSIONS: Intradialytic iron absorption was less impaired in non-diabteic patients with shorter ESRD duration. Therefore, intradialytic oral iron therapy could be successful in these patients.     

Recovery of contractile function of cryodamaged rat myocardium after transplantation of fetal cardiomyocytes and predifferentiated bone marrow stromal stem cells

The effect of cell transplantation into cryodamaged rat myocardium was studied on isolated hearts by increasing functional load to the left ventricle. Transplantation of allogeneic fetal cardiomyocytes improved the function of the left ventricle under conditions of considerably increased preload. Transplantation of autologous mesenchymal stem cells repaired leftventricular function under conditions of increased pre- and afterload.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 10, pp. 403–407, October, 2004     

Surgical management of extracranial carotid artery aneurysms

Between 1982 and 1991 we performed eight operations on seven patients with carotid artery aneurysms. Their mean age was 52.8 years (range: 20–67 years). Five aneurysms were atherosclerotic, one was associated with Marfan's syndrome, and two were pseudoaneurysms, one occurring after Dacron patch angioplasty and the other due to tuberculosis. Seven aneurysms were treated electively; one patient underwent an emergency surgical procedure. In one case, the internal carotid artery was ligated. Seven operations were reconstructive. No intraluminal shunt was used. No perioperative deaths occurred. Regressive hemiparesis and ipsilateral Horner's syndrome developed in one patient. The follow-up period ranged from six months to nine and a half years. One patient died of myocardial infarction three months after surgery.