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Biomedical subjects

S Sakura

Publications and source records attributed to S Sakura.

63 records · Page 4Linked to original sources
PubMed1982

Photolysis of pyridinoline, a cross-linking amino acid of collagen, by ultraviolet light.

Pyridinoline, a cross-linking amino acid of collagen, was degraded by irradiation of ultraviolet light. The decomposition rate varied with pH of the solution and wavelength of irradiation light. The maximum of the degradation rate at individual pH coincides with the ultraviolet absorption maximum. Namely, it was maximally degraded by irradiation at 295 nm in acidic solution and at 325 nm in neutral and alkaline solution. At the optimum wavelength, the photolysis occurred more rapidly in neutral and alkaline solution than in acidic solution. The quantum yield in neutral solution was approximately 0.11 and independent of wavelength. One of the photolysis products was identified as hydroxylysine on an amino acid analyser, indicating that the cleavage of the pyridinium ring occurred.

Amino Acids↗
PubMed1981

Electrochemical behaviour of pyridinoline, a crosslinking amino acid of collagen.

Pyridinoline is a crosslinking amino acid isolated from collagen. Polarographic oxidation and reduction potentials of pyridinoline were measured and compared with those of structurally related compounds, 3-hydroxypyridine, pyridoxine, pyridoxal, and N-methylpyridoxine. Oxidation and reduction potentials of these compounds were found to be near anodic and cathodic limit potentials, respectively, except for pyridoxal. This indicates that a 3-hydroxypyridine ring is very difficult to be reduced or oxidized. The reducibility of pyridinoline with a reducing agent, sodium borohydride, was also studied. It was not reduced by the reagent, however, it was found to be decomposed by light during the treatment. These results indicate that pyridinoline is a so-called "non-reducible" crosslink.

Amino Acids↗
PubMedDate not supplied

The effects of epidural anesthesia on ventilatory response to hypoxia.

STUDY OBJECTIVE: To evaluate the effects of epidural morphine on the ventilatory response to hypoxia in patients having abdominal surgery and to compare the effects of epidural lidocaine. DESIGN: Open-label, randomized study. SETTING: Shimane Medical University Hospital, Shimane, Japan. PATIENTS: Sixteen consenting, unpremedicated ASA physical status I and II patients undergoing abdominal surgery. INTERVENTIONS: Patients were administered 2 mg of morphine diluted in 10 ml of saline or 10 ml of 2% lidocaine from an epidural catheter that was inserted the day before surgery. MEASUREMENTS AND MAIN RESULTS: On the day before surgery, ventilatory parameters consisting of minute expiratory volume (VE), tidal volume (VT), respiratory frequency (f), and oxygen saturation by pulse oximeter (SpO2) were measured during resting state and hypoxic challenge. The same measurements were repeated 30 minutes after the epidural injection before surgery. The slope of VE/SpO2 decreased significantly from 1.6 +/- 0.3 to 1.2 +/- 0.2 after epidural morphine, although ventilatory values such as f, VT, VE, and PaCO2 were unchanged. Epidural lidocaine produced no significant changes in ventilatory response. CONCLUSION: Epidural anesthesia with morphine, but not lidocaine, reduced the ventilatory response to hypoxia indicated by VE/SpO2.

Abdomen↗
PubMedDate not supplied

Effect of lumbar epidural anesthesia on ventilatory response to hypercapnia in young and elderly patients.

STUDY OBJECTIVE: To examine the influence of age on resting ventilation, arterial blood gas tensions, and the ventilatory response to hypercapnia in lumbar epidural anesthesia. DESIGN: Clinical study using groups of young and elderly patients. SETTING: Surgical operation center of a university hospital. PATIENTS: Seven young (average age 39 years) and seven elderly (average age, 69 years) unpremedicated patients undergoing lower abdominal surgery. INTERVENTIONS: Patients were administered lumbar epidural anesthesia with 10 ml of 2% lidocaine. MEASUREMENTS AND MAIN RESULTS: Resting ventilation, arterial blood gas tensions, and ventilatory response to hypercapnia were measured before and 20 minutes after the block. Regarding the ventilatory response to hypercapnia, the mean slope of the hypercapnic response curve [change in minute ventilation (VE) divided by change in end-tidal partial pressure of carbon dioxide (PETCO2)] increased significantly following the epidural block, by 16% in the young patients and by 23% in the elderly patients, and the mean VE at a PETCO2 of 55 mmHg (VE55) also increased significantly, by 16% in the young subjects and by 26% in the older subjects. These changes in delta VE/delta PETCO2 and VE55 were statistically equivalent between the two age-groups. CONCLUSIONS: The effects of lumbar epidural anesthesia on resting ventilation, arterial blood gas tensions, and ventilatory response to hypercapnia were not affected by age.

Adult↗
PubMedDate not supplied

Comparative toxicity of glucose and lidocaine administered intrathecally in the rat.

BACKGROUND AND OBJECTIVES: Glucose is a common component of anesthetic solutions used for spinal anesthesia. However, its possible contribution to recent injuries occurring with spinal anesthesia has not been adequately addressed. Accordingly, the present studies compare the functional and morphologic effects of intrathecally administered glucose with those of lidocaine. METHODS: Twenty rats, implanted with intrathecal catheters, were divided into three groups to receive a 1-hour infusion of 5% lidocaine (n = 6), 10% glucose (n = 7), or normal saline (n = 7). Four days after infusion, animals were evaluated for persistent sensory impairment using the tail-flick test. Three days later, the animals were sacrificed, and the spinal cord and nerve roots were examined by a neuropathologist blinded to the solution received and the results of sensory testing. RESULTS: Lidocaine-treated animals exhibited persistent sensory impairment, whereas glucose- and saline-treated animals did not. Neuropathologic evaluation revealed moderate to severe nerve root injury in lidocaine-treated animals. Histologic changes in glucose- and saline-treated animals were minimal, similar, and restricted to the area adjacent to the catheter. Morphologic damage associated with lidocaine preferentially affected the nerve roots, with relative sparing of the spinal cord and dorsal root ganglia. CONCLUSIONS: These results suggest that, at clinically relevant concentrations, glucose does not induce neurologic injury, providing indirect evidence that recent clinical injuries occurring after spinal anesthesia resulted from a neurotoxic effect of the local anesthetic. Additionally, the present studies suggest that deficits resulting from neurotoxicity of intrathecally administered anesthetic result from injury to the axon.

Anesthesia, Spinal↗
PubMedDate not supplied

The addition of epinephrine increases intensity of sensory block during epidural anesthesia with lidocaine.

BACKGROUND AND OBJECTIVES: Little is known about the effect of adding epinephrine to local anesthetic solutions on the intensity of sensory block during epidural anesthesia. This study examined development of sensory block during lumbar epidural anesthesia using a cutaneous current perception threshold (CPT) quantitative sensory testing device. METHODS: Twenty ASA I patients who were randomly divided to receive 10 mL 1% lidocaine with (group E) or without (group P) epinephrine 1:200,000. Current perception threshold at 2,000, 250, and 5 Hz stimulation at the trigeminal (V), ninth thoracic (T9), and second lumbar (L2) dermatomes, and the dermatomal levels of block of light touch, temperature, and pinprick discrimination were measured before and every 5 minutes, until 60 minutes after injection of epidural lidocaine. RESULTS: After epidural administration of lidocaine with epinephrine, all CPT significantly increased at T9 and L2, whereas no increase was detected after epidural plain lidocaine. Areas under the curves, calculated to express overall magnitude and duration of CPT values, were significantly larger in group E than those in group P at 2,000 and 250 Hz at T9. No differences were observed in the maximal levels of loss of cold, pinprick, and touch sensations between both groups. CONCLUSIONS: These results suggest that lumbar epidural anesthesia using 10 mL 1% lidocaine with epinephrine produces a more intense block of both large and small diameter sensory nerve fibers than that with plain lidocaine. It appears, therefore, that the addition of epinephrine improves the quality of sensory block during epidural anesthesia with lidocaine.

Adrenergic Agonists↗
PubMedDate not supplied

Lumbar sympathetic block for pain relief in two patients with interstitial cystitis.

BACKGROUND AND OBJECTIVES: Interstitial cystitis (IC) is characterized clinically by lower abdominal pain, pain during urination, and increased frequency of urination. Treatment of the symptoms in IC remains challenging. We report effective treatment using lumbar sympathetic block for 2 patients with IC. CASE REPORT: A 63-year-old and 78-year-old woman were diagnosed with IC. Medical therapy with nonsteroidal anti-inflammatory drugs (NSAID), anticholinergics, and hydrodistention of the bladder failed to improve their symptoms. Subsequently, a continuous lumbar epidural block using 1% mepivacaine was used in these patients. A transient reduction of the symptoms in both patients was achieved. A lumbar sympathetic block with a neurolytic agent produced almost complete, and long-lasting relief of their symptoms. CONCLUSION: Lumbar sympathetic block using a neurolytic agent produced long-lasting pain relief in 2 patients with IC. Reg Anesth Pain Med 2001;26:271-273.

Aged↗
PubMedDate not supplied

Spinal anesthesia with tetracaine in 0.75% glucose: influence of the vertebral interspace used for injection.

BACKGROUND AND OBJECTIVES: The anesthetic behavior and hemodynamic consequences of spinal anesthesia with marginally hyperbaric tetracaine containing a low concentration of glucose injected at two different interspaces were examined and compared with those of conventionally hyperbaric solution. METHODS: One-hundred twenty ASA Physical Status I or II patients scheduled for elective surgery to the lower limb were sequentially assigned to one of three equal groups to receive spinal anesthesia: Group 1 received 0.5% tetracaine in 0.75% glucose with 0.125% phenylephrine at the L2-L3 interspace; group 2 0.5% tetracaine in 0.75% glucose with 0.125% phenylephrine at the L3-L4 interspace; group 3 0.5% tetracaine in 7.5% glucose with 0.125% phenylephrine at the L3-L4 interspace. Neural block was assessed in a double-blinded manner by cold, pinprick, and touch sensation, and a modified Bromage scale after the injection of the study drug. RESULTS: Injection at the L2-L3 interspace produced significantly higher spread of analgesia [median T7 (10th, 90th percentiles T10, T4)] than injection at L3-L4 interspace [T10 (L1, T5)] when using the solution in 0.75% glucose. There were no significant differences in peak dermatomal levels between groups 1 and 3, but the number of patients who required ephedrine for the treatment of hypotension was larger in group 3. CONCLUSIONS: A marginally hyperbaric tetracaine solution injected at the L2-L3 interspace with the patient in the lateral position produced greater extent of cephalad spread than that at the L3-L4 interspace. When compared to a conventionally hyperbaric tetracaine solution injected at the L3-L4 interspace, the marginally hyperbaric solution injected at the L2-L3 interspace caused less hemodynamic variability despite similar levels of maximum sensory block.

Anesthesia, Spinal↗