Heat generation by ultrasonic bone curette comparing with high-speed drill.

BACKGROUND: Ultrasonic bone curettes have been used as with high-speed drills. However, the amount of heat generated by the ultrasonic bone curette is not well known. This study quantitatively assessed the heat generated by an ultrasonic bone curette and compared it to that by a high-speed drill. METHODS: The thermal change in a swine skull during bone curetting using an ultrasonic device and a high-speed drill were assessed. The investigation focused on the type of surgical manipulation (brush-like strokes vs. pushing motion) and irrigation (room temperature vs. cold water; low-volume irrigation vs. high-volume irrigation). RESULTS: The thermal elevation during drill use was suppressed when using brush-like strokes compared to pushing motion (brush-like strokes, 44.7 °C; pushing motion, 69.2 °C; p < 0.01). Cold-water irrigation while drilling had a small effect compared to room temperature (RT) water (RT, 44.7 °C; cold, 35.2 °C; p = 0.12). The temperature generated by the curette was higher than that generated by the drill (curette, 72.5 °C; drill, 44.7 °C; p < 0.01). High-volume irrigation was required to reduce the heat generated by the curette (no irrigation, 88.6 °C; low-volume, 72.5 °C; high-volume, 60.5 °C; p < 0.01). CONCLUSIONS: The ultrasonic bone curate generated more heat than the high-speed drill. During surgical manipulation, the use of brush-like strokes by both the high-speed drill and the ultrasonic bone curette is necessary to avoid excess thermal elevation. Irrigation with RT water is sufficient to avoid heat generation. High-volume irrigation is required to reduce the heat generated by the curette.

Preventive replacement policies with time of operations, mission durations, minimal repairs and maintenance triggering approaches.

When a mission arrives at a random time and lasts for a duration, it becomes an interesting problem to plan replacement policies according to the health condition and repair history of the operating unit, as the reliability is required at mission time and no replacement can be done preventively during the mission duration. From this viewpoint, this paper proposes that effective replacement policies should be collaborative ones gathering data from time of operations, mission durations, minimal repairs and maintenance triggering approaches. We firstly discuss replacement policies with time of operations and random arrival times of mission durations, model the policies and find optimum replacement times and mission durations to minimize the expected replacement cost rates analytically. Secondly, replacement policies with minimal repairs and mission durations are discussed in a similar analytical way. Furthermore, the maintenance triggering approaches, i.e., replacement first and last, are also considered into respective replacement policies. Numerical examples are illustrated when the arrival time of the mission has a gamma distribution and the failure time of the unit has a Weibull distribution. In addition, simple case illustrations of maintaining the production system in glass factories are given based on the assumed data.

The influence of hypoglycemia on cerebral blood flow in cases of hypoglycemic coma.

The authors report two cases of hypoglycemic coma in which both diffusion-weighted imaging (DWI) and single photon emission computed tomography (SPECT) were used. A 74-year-old woman (case 1) presented with deep coma associated with hypoglycemia (blood glucose level: 20 mg/dl), and DWI on admission revealed extensive hyperintensity lesions. SPECT obtained on the second hospital day revealed diffuse hyperperfusion and a follow-up SPECT on the eighth hospital day showed relative hypoperfusion. An 89- year- old woman (case 2) presented with coma associated with hypoglycemia (blood glucose level: 45 mg/dl), and DWI showed diffuse hyperintensity lesions in both hemispheres. SPECT obtained on the ninth hospital day showed relative hypoperfusion compared to the first scan obtained on the third hospital day. Although the blood glucose level was rapidly corrected, the level of consciousness remained unchanged in both cases. Our results suggest that cerebral blood flow may increase even after glucose correction and that relative hypoperfusion could occur in the subacute stage of hypoglycemic coma.

Reversible diffusion-weighted imaging changes in the splenium of the corpus callosum and internal capsule associated with hypoglycemia - case report - .

A 63-year-old man presented with hypoglycemia-induced hemiparesis manifesting as diffusion-weighted magnetic resonance (MR) imaging changes in the splenium of the corpus callosum and internal capsule which disappeared after glucose administration. Clinicians should be aware that hypoglycemia can cause reversible splenium abnormalities on MR imaging, although the underlying mechanism still remains unclear, as this may be helpful in the differential diagnosis of hypoglycemia-induced hemiparesis and stroke.

[Clinical Features of Very Elderly Patients Aged 90 Years or Above with Acute Ischemic Stroke: A Study by Using Diffusion Weighted Brain Magnetic Resonance Imaging].

We investigated the diffusion weighted magnetic resonance imaging (DWI) features of 76 very elderly patients aged 90 years or above with acute ischemic stroke. Stroke subtypes were classified into five types according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) and the Japanese Stroke Databank. The incidence rates of atherothrombotic brain infarction (ATBI), atherothrombotic brain embolism (ATBE), lacunar infarction (LI), cardiogenic brain embolism (CBE) and undetermined type of brain infarction (UTBI) were 2.6%, 17.1%, 10.5%, 50.0% and 19.8%, respectively. We estimated that the incidence of acute ischemic stroke in women was 3.5-fold higher than that in men. This is likely because survival rate of females is higher than that of males in populations aged 90 years or above. The prevalence of atrial fibrillation (AF) was 46.1% in patients with brain infarctions, and 92.1% in patients with CBE. The frequency of multiple infarctions is 52.6% and that of single infarction is 47.4%. In DWI of lesions, the frequencies of territorial infarction in the cerebral hemisphere, borderzone infarction, and vertebrobasilar infarction were 85.5%, 13.2% and 17.1%, respectively. The frequencies of massive territorial infarction and cerebellar infarction were 23.7% and 13.2%, respectively. With regard to the relationship between DWI lesion topography and stroke subtypes, superficial infarctions in the cerebral hemisphere were seen in patients with ATBE, CBE and UTBI. Single infarctions deep in the cerebral hemisphere were seen in all patients with any of the five stroke subtypes. Massive territorial infarctions with infarctions in other sites of the cerebral hemisphere or vertebrobasilar region were seen only in patients with CBE, and single pontine infarction was seen only in patients with LI. (Received November 19, 2015; Accepted July 3, 2017; Published November 1, 2017).

Affinity labeling of a catalytic site, cysteine(247), in rat mercaptopyruvate sulfurtransferase by chloropyruvate as an analog of a substrate.

A bisubstrate enzyme, rat mercaptopyruvate sulfurtransferase (EC 2.8.1.2), is inactivated by 3-chloropyruvate, an analog of 3-mercaptopyruvate serving as a sulfur-donor and -acceptor substrate. To elucidate a reaction mechanism of the enzyme, the inactivation kinetic studies using 3-chloropyruvate were carried out. However, 3-chloropyruvate cannot be mixed with 3-mercaptopyruvate, 2-mercaptoethanol and thiosulfate because these substrates decompose 3-chloropyruvate. Thus, 3-mercaptopyruvate sulfurtransferase was incubated with 3-chloropyruvate, and then the remaining activity was measured separately in the assay system containing 3-mercaptopyruvate and 2-mercaptoethanol. The inactivation kinetics was analyzed by Kitz and Wilson method (J. Biol. Chem. 237 (1962) 3245-3248). The inactivation of mercaptopyruvate sulfurtransferase by 3-chloropyruvate proceeded in one-on-one manner and exhibited pseudo first-order kinetics with k(inact) = 0.068 +/- 0.003 min(-1) and K(I) = 4.0 +/- 0.2 mM (n = 3, mean +/- S.D.). Further, SH titration using DTNB revealed that MST was inactivated by 3-chloropyruvate in a 1:1 stoichiometry. Site-directed mutagenesis for binding sites of 3-mercaptopyruvate (Arg(187)-->Gly or Arg(196)-->Gly) (J. Biol. Chem. 271 (1996) 27395-27401) did not critically affect the inactivation. These findings suggest that 3-chloropyruvate behaves as an affinity label and directly tags the catalytic site, Cys(247). An ESI-LC/Q-TOF mass spectrometric study suggests that a pyruvate adduct is formed at Cys(247), which mimics a reaction intermediate.

Internal trapping following proximal clipping for a ruptured partially thrombosed giant aneurysm of the vertebral artery--case report.

A 52-year-old woman presented with a partially thrombosed giant aneurysm of the vertebral artery (VA) manifesting as a 3-month history of left hemiparesis. She developed subarachnoid hemorrhage during hospitalization and underwent emergency surgery for surgical proximal clipping and ventricular drainage with decompressive suboccipital craniectomy. She underwent additional surgery for endovascular coil embolization of the aneurysm and the affected distal VA on the 7th postoperative day. Although she suffered transient lower cranial nerve pareses and respiratory failure, her neurological condition improved gradually and she returned home with only slight ataxia and hoarseness 3 months after surgery. Magnetic resonance imaging obtained 28 months postoperatively revealed a remarkable decrease in the size of the aneurysm as well as reduction of the mass effect on the brainstem. Combined proximal clipping and internal trapping can solve the problems associated with treatment of giant aneurysms of VA by either direct surgery or endovascular surgery, and should be considered as a therapeutic option for giant aneurysms of the VA.

A case of Lhermitte-Duclos disease presenting high FDG uptake on FDG-PET/CT.

Lhermitte-Duclos Disease (LDD) is a rare cerebellar lesion that has long been controversial as to whether the entity is a hamartoma, a malformation, or a neoplasm. Recent advances in metabolic imaging and molecular biology have unveiled biological features of LDD and a close relationship between LDD and Cowden disease. Adult onset LDD is now considered identical to Cowden disease in a US guideline. We present a case of LDD, in which high fluorodeoxy glucose (FDG) uptake was shown on PET/CT. We performed dual time point scans, in which a delayed scan exhibited more intense FDG uptake by the hamartomatous lesion than an early scan. We must remain aware of the possibility of LDD when intense accumulation is observed in a cerebellar lesion on FDG-PET/CT imaging.

Identification of 4-S-Cysteinyltetrodotoxin from the liver of the puffer fish, Fugu pardalis, and formation of thiol adducts of tetrodotoxin from 4,9-anhydrotetrodotoxin.

The metabolic pathway of tetrodotoxin (TTX), a powerful and specific voltage-gated sodium channel blocker, has not been well-clarified either in TTX-poisoned patients or in puffer fish. 4-S-CysteinylTTX (4-CysTTX) was isolated from the liver of the puffer fish, Fugu pardalis, as the first adduct of TTX with thiol. The structure was fully characterized by electrospray ionization-MS and two-dimensional NMR spectroscopy. The configuration of Cys in this compound was confirmed to be S (L-Cys) by application of the Marfey's method to cystine obtained from 4-CysTTX by iodine oxidation. We also found that 4-CysTTX was derived from 4,9-anhydroTTX by incubation with a large excess of Cys in aqueous buffer (pH 8.0) for 90 min at 40 degrees C in 33% yield by HPLC. GSH also reacted with 4,9-anhydroTTX to form 4-S-glutathionylTTX (4-GSTTX) in 39% yield under the same conditions, whereas TTX scarcely reacted with Cys and GSH. These reactions were strictly pH-dependent, giving the highest yield at pH 8.0. 4-GSTTX was converted to 4,9-anhydroTTX in 0.8 M sodium phosphate buffer (pH 8.0) at 25 degrees C. Its half-life was approximately 4 h. The minimum lethal doses of 4-CysTTX and 4-GSTTX to mice by ip injection were more than 140 and 860 microg/kg (n = 2), which were 14- and 86-fold larger than the LD(50) of TTX, respectively. 4-GSTTX was hydrolyzed to 4-CysTTX by gamma-glutamyltranspeptidase (Sigma, catalog no. G9270), which was supposed to contain cysteinylglycine dipeptidase. We also examined the effect of Cys or GSH coinjection (ip) with TTX to mice for detoxification of TTX and concluded that these coinjections did not reduce the toxicity of TTX.

Renal angiomyolipoma: relationships between tumor size, aneurysm formation, and rupture.

PURPOSE: To evaluate the relationships between tumor size, aneurysm formation, and spontaneous rupture in renal angiomyolipomas. MATERIALS AND METHODS: Twenty-three patients with renal angiomyolipoma were examined with angiography and computed tomography (CT). The single largest lesion in each kidney was evaluated. Tumor size was measured at CT, and aneurysm size was measured at renal angiography. Tumor and aneurysm sizes were compared between the group with ruptured angiomyolipoma and the group with unruptured angiomyolipoma. Multiple regression analysis was performed to identify factors affecting rupture. RESULTS: Twenty-nine kidneys with angiomyolipoma were identified. Eight angiomyolipomas were hemorrhagic; the remaining 21 were not hemorrhagic. Tumor size was larger than 4 cm and aneurysm size was 5 mm or larger in all hemorrhagic lesions. There were significant differences in mean tumor size (11.4 cm +/- 5.5 [SD] vs 5.0 cm +/- 3.1, P <.02) and mean aneurysm size (13.3 mm +/- 6.2 vs 2.4 mm +/- 2.9, P <.02) between the ruptured and unruptured tumor groups. When tumor size of 4 cm or larger and aneurysm size of 5 mm or larger were used as predictors of rupture, sensitivity and specificity, respectively, were 100% and 38% with the former criterion and 100% and 86% with the latter criterion. Multiple regression analysis indicated that aneurysm size was the most important factor linked to rupture. CONCLUSION: Aneurysm formation appears to be related to tumor size, and large aneurysms confer a higher probability of rupture.