Biomedical subjects
Publications and source records attributed to T Sakamoto.
We report a patient with meningioma and radiological findings of erosive bony change, who developed venous air embolism via the diploic vein in the eroded inner table of the skull during craniotomy in the sitting position. The findings in our case suggest that preoperative radiological imaging evaluation can increase an awareness of the possibility of venous air embolism.
We report our experience with anesthetic care for six patients with pseudoankylosis of the mandible following neurosurgical procedures, four of whom required fiberoptically guided intubation for anesthesia. We suggest that the development of operative approaches and reconstruction techniques in skull base surgery may increase the risk of difficult airway due to limitation of mouth opening.
In order to reduce intraoperative blood loss and spare blood transfusion, we developed a blood pressure control system using a state-predictive controller. Using adult mongrel dogs, the mean arterial pressure (MAP) was recorded from a femoral artery while trimethaphan camsilate was infused at constant rates. A pure delay plus a first-order delay model was then derived from the dose-response curves and the values of plant parameters (gain, time-constant, dead-time, and so on) were estimated based on the experimental data. For this model, a state-predictive servo system was designed to cope with the pure delay existing in the model, and simulated. In order to evaluate the accuracy and reliability of this system, we experimented on dogs. With a reference MAP set at 60 mmHg, the MAP reached the reference level in 5.8 to 26.5 min. The duration of error from the reference MAP (+/- 10%) was 2.3 +/- 3.9 min/h (n = 7). These results indicated the safety and stability of our system.
Twenty male patients with sleep apnea syndrome were treated with acetazolamide (AZM), a carbonic anhydrase inhibitor. In 14 of the patient a significant decrease was found in the number of apnea, apnea index and % apnea time (percentage of time spent with apnea to the total sleep time) with improvement in sleep structure, clinical symptoms, such as insomnia, daytime excessive sleepiness and snoring. A significant decrease was also observed in arterial blood pH and HCO-3 in the 14 improved patients. On the other hand, no improvement occurred in the parameters of sleep apnea and sleep with AZM in the remaining six patients. Moreover, metabolic acidosis and an improvement in arterial blood gases did not occur with AZM in the six patients.
We investigated the effects of human corticotropin-releasing hormone (hCRH) on the sleep structure and body temperature rhythms of seven healthy young men. Polysomnographic recordings were obtained and body temperatures were monitored continuously for 48 h in each subject following the intravenous administration of saline or of 100 micrograms hCRH. The administration of hCRH was associated with a significant phase-advancement in body temperature rhythm vs the saline control. The administration of hCRH affected non-rapid eye movement (NREM) sleep by reducing significantly slow wave sleep (SWS) and sleep efficiency, whereas the percentage of sleep stages 1 and 2 were increased significantly. These changes in body temperature rhythms and sleep structure induced by hCRH resembled those observed in patients with endogenous depression, except for the findings during rapid eye movement (REM) sleep. We hypothesize that a hypersecretion of hCRH in patients with endogenous depression may help to explain the changes in body temperature rhythms and sleep structure often reported in such patients.
In the early 1980's methicillin-resistant staphylococcus aureus (MRSA) was reported as a major pathogenic organism of geriatric hospital infection in Japan. At the same time in the A geriatric hospital MRSA infection was prevalent. To decrease nosocomial infections some active preventive measures against hospital infection were taken since Oct. 1991. About a year before introduction of prevention of hospital infection in the geriatric ward (190 beds) of A hospital 193 episodes of nosocomial bacteremia were observed. However a year after introduction of preventive measures episodes of nosocomial bacteremia were decreased to less than a half (45.6%) in comparison to the number before introduction of prevention. As a causative organism gram-positive bacteria including MRSA were markedly decreased. Major portals of entry of bacteremia (74.9%) were urinary-tract system, intravenous hyperalimentation (IVH) catheter, and pressure sores. MRSA-positive pressure sores were decreased to 20.4% of those before prevention. On the other hand 87 episodes of nosocomial pneumonia were observed before prevention. However a year after introduction of preventive measures episodes of nosocomial pneumonia were decreased to less than a half (44.8%) in comparison to the number before introduction of prevention. After prevention MRSA and mixed infection of P. aeruginosa and MRSA were markedly decreased. The decrease of bacteremia and nosocomial pneumonia were caused by cleaning hands, the preventive measures for decrease and improvement of pressure sores, cleaning the upper respiratory tract for prevention of lower respiratory-tract infection cleaning floors and education of the staff, etc.
BACKGROUND: Sodium metabisulphite (MBS) is known to induce bronchoconstriction in asthmatic patients. The effects of MBS on guinea pig airway smooth muscle and on neurally mediated contraction in vitro have been examined. METHODS: Tracheal and bronchial airway segments were placed in oxygenated buffer solution and electrical field stimulation was performed in the presence of indomethacin (10(-5) M) and propranolol (10(-6) M) for the measurement of isometric tension. Atropine (10(-6) M) was added to bronchial tissues. RESULTS: Concentrations of MBS up to 10(-3) M had no direct effect on airway smooth muscle contraction and did not alter either tracheal smooth muscle contraction induced by electrical field stimulation at all frequencies or acetylcholine-induced tracheal smooth muscle contraction. There was a similar response in the absence of epithelium, except for potentiation of the response induced by electrical field stimulation at 0.5 Hz (24 (10)% increase). However, MBS (10(-5), 10(-6) and 10(-7) M) augmented neurally-mediated non-adrenergic non-cholinergic contractile responses in the bronchi (13.3 (3.2)%, 23.8 (9.6)%, and 6.4 (1.6)%, respectively). MBS had no effect on the contractile response induced by substance P, but at higher concentrations (10(-3) M and 10(-4) M) it caused a time-dependent attenuation of responses induced by either electrical field stimulation or exogenously applied acetylcholine or substance P. CONCLUSIONS: MBS had no direct contractile responses but enhanced bronchoconstriction induced by activation of non-cholinergic neural pathways in the bronchus, probably through increased release of neuropeptides. At high concentrations MBS inhibited contractile responses initiated by receptor or neural stimulation.
Proliferative vitreoretinopathy (PVR) is the most common cause for failure of retinal reattachment surgery. In a search for better pharmacologic treatment of PVR, we investigated the effect of intravenous injections of suramin on an experimental rabbit model of PVR. PVR was induced in rabbits by intravitreal injection of autologous fibroblasts. The experimental group (7 eyes) received intravenous injections of suramin (100 mg/kg body weight) every 3 days for 15 days, beginning 3 days before fibroblast injection. The control group (5 eyes) was treated similarly but received intravenous saline solution in place of suramin. A third group (4 eyes) received suramin according to the protocol above but did not receive intravitreal fibroblasts. The animals were examined by indirect ophthalmoscopy every 3 days and were sacrificed 14 days after the injection of fibroblasts. The serum levels of suramin were evaluated by high-performance liquid chromatography. The PVR was classified as stages I-V, based upon clinical findings. PVR developed in both experimental and control animals but was less severe in those treated with suramin. On day 14, the average stage of PVR in the control group was 3.8; in the suramin-treated group, however, the average stage was 2.4, which was significantly less than in the control group (p < 0.02). None of the rabbits in the third group showed pathologic changes. Serum levels of suramin were maintained at an average of 280.2 micrograms/ml and no apparent toxicity was found in the retina by histologic study.(ABSTRACT TRUNCATED AT 250 WORDS)
The cholesteryl ester transfer protein (CETP) transfers lipids among lipoprotein particles and plays a central role in lipoprotein metabolism. Humans with genetic deficiency of CETP have both elevated HDL cholesterol and apolipoprotein A-I concentrations as well as decreased LDL cholesterol and apolipoprotein B levels. The present study was undertaken to elucidate the metabolic basis for the decreased LDL cholesterol and apo B levels in CETP deficiency. We conducted a series of in vivo apo B kinetic studies in tow unrelated homozygotes with CETP deficiency and in control subjects. A primed constant infusion of stable isotopically labeled phenylalanine was administered to the two CETP deficient subjects and control subjects and apo B kinetic parameters in VLDL, intermediate density lipoproteins, and LDL were obtained by using a multicompartmental model. The fractional catabolic rates (FCR) of LDL apo B were significantly increased in the CETP-deficient subjects (0.56 and 0.75/d) compared with the controls (mean FCR of 0.39/d). Furthermore, the production rates of apo B in VLDL and intermediate density lipoprotein were decreased by 55% and 81%, respectively, in CETP deficiency compared with the controls. In conclusion, CETP-deficient subjects were demonstrated to have substantially increased catabolic rates of LDL apo B as the primary metabolic basis for the low plasma levels of LDL apo B. This result indicates that the LDL receptor pathway may be up-regulated in CETP deficiency.
The number and exact locations of the major histocompatibility complex (MHC)-linked diabetogenic genes (Idd-1) are unknown because of strong linkage disequilibrium within the MHC. By using a congenic NOD mouse strain that possesses a recombinant MHC from a diabetes-resistant sister strain, we have now shown that Idd-1 consists of at least two components, one in and one outside the class II A and E regions. A new susceptibility gene (Idd-16) was mapped to the < 11-centiMorgan segment of chromosome 17 adjacent to, but distinct from, previously known Idd-1 candidates, class II A, E, and Tap genes. The coding sequences and splicing donor and acceptor sequences of the Tnfa gene, a candidate gene for Idd-16, were identical in the NOD, CTS, and BALB/c alleles, ruling out amino acid changes in the TNF molecule as a determinant of insulin-dependent diabetes mellitus susceptibility. Our results not only map a new MHC-linked diabetogenic gene(s) but also suggest a new way to fine map disease susceptibility genes within a region where strong linkage disequilibrium exists.
To clarify the role of renal dopaminergic activity in patients with primary aldosteronism (PA), urinary excretion of free dopamine (DA) and the conversion ratio of DA from l-dopa in the kidney were investigated in 8 patients with PA and 10 normotensive subjects (NT). All subjects were hospitalized and received a standard diet (Na 120 mEq, K 75 mEq/day) and 2 h renal clearance test was performed. Plasma l-dopa concentration (p-DOPA), creatinine clearance (Ccr), urinary excretion of sodium (UNaV) and DA (uDA) as well as fractional excretion of sodium (FENa) were measured. No significant difference was found in UNaV or FENa between NT and PA, or between before and after adrenalectomy (Adx) in PA. UDA was significantly higher in PA than NT, and decreased significantly after Adx. There was no difference in the product of Ccr X p-DOPA between NT and PA, or between before and after Adx in PA. The ratio of uDA/(Ccr X p-DOPA) was significantly higher in PA than NT. After Adx this ratio decreased significantly to the normal range. These results suggest that (1) renal dopaminergic activity is augmented and contributes to the escape phenomenon in PA, and (2) augmented renal DA production in PA might be caused by an increase of conversion to DA from l-dopa at the renal proximal tubules.
Soluble polypeptides extracted from adult Fasciola sp. were analysed by SDS-PAGE, and their antigenicity was characterized by enzyme-linked immunotransfer blot (EITB) using sera from experimentally and naturally infected cattle. Polypeptides of adult Fasciola sp. with estimated molecular mass of 64-52 kDa, 38-28 kDa, 17 kDa, 15 kDa, 13 kDa and 12 kDa, were recognized by sera obtained in both early and late stages of infection. Furthermore, two polypeptides of more than 160 kDa were detected by sera only in the early stage of infection. The results of EITB using sera of dairy cows naturally infected with Fasciola sp. suggest that polypeptides of 64-52 kDa may be candidates as serodiagnostic antigen of bovine fascioliasis.
The motility of both intact and demembranated fowl spermatozoa was vigorous at 30 degrees C, but decreased markedly following the addition of 1-(5-chloronaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-9), a specific inhibitor of myosin light chain kinase (MLCK). Furthermore, the presence of a MLCK substrate peptide also inhibited the motility of demembranated spermatozoa at 30 degrees C. In contrast, the addition of N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H-8) or N-(2-guanidinoethyl)-5-isoquinolinesulfonamide dihydrochloride (HA1004), specific inhibitors of cAMP-dependent protein kinase, did not appreciably affect the motility of either intact or demembranated spermatozoa. Cyclic AMP-dependent protein kinase substrate peptides were also ineffective for the inhibition of motility of demembranated spermatozoa at 30 degrees C. Immunoblotting of sperm extract, using an antibody to MLCK, revealed two major crossreacting proteins of 130 kDa and 61-64 kDa, which corresponded to the molecular mass of MLCK. In addition, immunogold particles, which reacted with the anti-MLCK antibody, were observed around or on the axoneme at the ultrastructural level. These results suggest that the phosphorylation of axonemal protein(s) by MLCK, or a MLCK-like protein, rather than by cAMP-dependent protein kinase, may be involved in the maintenance of fowl sperm motility at 30 degrees C.
We studied the prognostic applicability of electroencephalograms (EEGs) of seventy-nine patients within 24 hours after successful cardiopulmonary resuscitation. The EEGs were classified into five grades according to a modified Hockaday's scale. The EEGs of grades I and II implied full recovery, while those of grade III gave a varied but generally unfavorable prognosis. Patients with grades IV and V EEGs survived in a vegetative condition or died without awakening. Eighteen patients showed EEG with periodic patterns, all of which led to a fatal or vegetative outcome. One case showed EEGs associated with periodic triphasic waves and repetitive sharp transients in the same record. Several cases showed EEGs with different periodic patterns in consecutive records. We conclude that an EEG is a good indicator of patient prognosis after cardiopulmonary resuscitation. However, the clinical significance of morphological differences of various periodic patterns that can occur during an EEG remains to be established.
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BACKGROUND: The direct contribution of bile to gastric inhibitory polypeptide (GIP) release and the role of bile in regulating GIP secretion in response to fat ingestion are still obscure. The present study was aimed to clarify the influence of bile on GIP release. METHODS: Seven patients with obstruction of the common bile duct and nine volunteers participated in the study. Fifty milliliters of Lipomul was ingested, and GIP was measured serially for 180 min. After intraduodenal instillation of pooled autologous bile for 2 days, the same study was carried out. RESULTS: The fat-stimulated GIP response was significantly lower in the patients than in the controls. The basal GIP level did not change on bile instillation, but the GIP response to fat ingestion was significantly increased on bile instillation compared with that in the absence of bile. CONCLUSIONS: Intraluminal bile alone does not stimulate the secretion of GIP, but it promotes GIP secretion in response to fat ingestion.
Vascular endothelial cells play an important role in progression or healing of various retinal or choroidal diseases and they have a broad organ specificity. We have grown and studied human choroidal endothelial cells (CECs) cultured in a collagen gel, where they form tube-like structures. CECs were differentially isolated from choroidal tissues and cultured to near homogeneity. The cells were embedded in a type I collagen gel in 24-well culture dishes and incubated with M199 medium containing 10% fetal calf serum. Gels were observed using phase contrast microscopy and were evaluated histologically by light and electron microscopy. The CECs were strongly positive for factor VIII-related antigen and actively ingested diI-acetylated LDL, indicating their endothelial nature. Ultrastructural analysis of the tube-like structures revealed a central lumen surrounded by cells joined apically by junctions and showing prominent pinocytotic activity, fenestrations and basement membrane formation; these features are typical of CECs in vivo. This preparation should be a useful tool to study the development of physiology and pathology of choroidal endothelium.