Four cases of human herpesvirus 6 variant B infection after pediatric liver transplantation

BACKGROUND: Little is known about human herpesvirus (HHV)-6 infection after liver transplantation. We present our experiences with four cases of HHV-6 infection after liver transplantation from living related donors. METHODS: Peripheral blood was collected from four donor and recipient pairs at the time of transplantation and biweekly from the recipients after transplantation. We attempted to isolate HHV-6 and measure antibody titers to HHV-6 and HHV-7. RESULTS: HHV-6 was isolated from four recipients approximately 2 weeks after transplantation. A significant rise in HHV-6 antibody titers was observed in four recipients at some point in their course, whereas HHV-7 antibody titers were increased in one recipient. Four isolates were variant B. When HHV-6 was isolated, all recipients had an unexplained fever. CONCLUSIONS: HHV-6 variant B infection after pediatric liver transplantation was confirmed. HHV-6 infection occurred approximately 2 weeks after transplantation. Moreover, there appears to be an association between HHV-6 infection and unexplained fever.     

An acute experiment on retrograde intestinal peristalsis with emesis using decerebrated dogs

This acute experiment using decerebrated dogs was a new model for studies of central and peripheral mechanisms of intestinal motility with emesis, and was undertaken to clarify the relationship between intestinal contractions and the retrograde transport of intestinal contents with emesis. Contractility of the small intestine was recorded by five force transducers. Reflux of mannitol solution injected into the small intestine through the proximal duodenum was recorded by a magnetic flow meter. Retching was induced by vagal afferent stimulation, intramuscular apomorphine, or intragastric copper sulfate. Intestinal contractility was enhanced preceding retching caused by these emetic stimuli. Characteristic contractions in the oral direction were observed in the small intestine before and during retching. These contractions originated in the caudal or middle intestine and conducted to the duodenum intermittently, rather than continuously. Reflux of mannitol solution to the proximal duodenum was observed just after the initiation of retching, and was sometimes observed repeatedly during retching. These results suggest that intestinal contents are repeatedly transported to the proximal duodenum during retching by intermittent retrograde contractions. Acute experiments using decerebrated dogs seem to be useful and essential for studies of central and peripheral mechanisms of emesis.     

Dual regulation of the skeletal muscle ryanodine receptor by triadin and calsequestrin

Triadin, a calsequestrin-anchoring transmembrane protein of the sarcoplasmic reticulum (SR), was successfully purified from the heavy fraction of SR (HSR) of rabbit skeletal muscle with an anti-triadin immunoaffinity column. Since depletion of triadin from solubilized HSR with the column increased the [3H]ryanodine binding activity, we tested a possibility of triadin for a negative regulator of the ryanodine receptor/Ca2+ release channel (RyR). Purified triadin not only inhibited [3H]ryanodine binding to the solubilized HSR but also reduced openings of purified RyR incorporated into the planar lipid bilayers. On the other hand, calsequestrin, an endogenous activator of RyR [Kawasaki and Kasai (1994) Biochem. Biophys. Res. Commun. 199, 1120-1127; Ohkura et al. (1995) Can. J. Physiol. Pharmacol. 73, 1181-1185] potentiated [3H]ryanodine binding to the solubilized HSR. Ca2+ dependency of [3H]ryanodine binding to the solubilized HSR was reduced by triadin, whereas that was enhanced by calsequestrin. Interestingly, [3H]ryanodine binding to the solubilized HSR potentiated by calsequestrin was reduced by triadin. Immunostaining with anti-triadin antibody proved that calsequestrin inhibited the formation of oligomeric structure of triadin. These results suggest that triadin inhibits the RyR activity and that RyR is regulated by both triadin and calsequestrin, probably through an interaction between them. In this paper, triadin has been first demonstrated to have an inhibitory role in the regulatory mechanism of the RyR.     

Elimination of artifacts in MRCP: technical consideration

Artifacts of MR cholangiopancreatography (MRCP) include fluid-filled gastrointestinal tracts, respiratory motion artifacts, spasm of Oddi's sphincter, vascular compression of bile ducts, overlapping of various anatomical structures and bright signal of surrounding fatty tissue. In this article, various technical considerations to eliminate these artifacts were described for the better imaging analysis of MRCP. The use of high-concentration ferric ammonium citrate (Ferriseltz) is recommended to reduce bright signal of fluid-filled gastrointestinal tracts. In case of long breathhold sequences, O2-inhalation study is useful to eliminate respiratory motion artifacts. Careful attention should be paid to the spasm of Oddi's sphincter and the vascular compression of bile ducts to avoid erroneous interpretation of MRCP findings.     

Highwall Stability due to Punch Mining at Opencut Coal Mines

Conventional highwall mining extracts coal with an auger machine or a continuous miner from exposed seams at the base of opencut or strip operations. However, under poor strata and high stress conditions, highwall mining cannot be conducted due to pillar and roof failures. In such cases, punch highwall mining is more effective than the conventional highwall mining. This paper describes conventional highwall mining and punch highwall mining systems and discusses the stability of the highwall due to punch highwall mining at opencut coal mines.     

Usefulness of percutaneous cardiopulmonary bypass support in patients with difficulties in weaning from cardiopulmonary bypass

A percutaneous cardiopulmonary support system (PCPS) was used in 12 patients (mean age 68 years) between March 1991 and June 1996 for difficulties weaning from ordinary cardiopulmonary bypass. Cardiac procedures preceding the placement of the PCPS were coronary artery bypass grafting in 8 patients, aortic valve replacement in 1, double valve replacement in 1, and ascending aortic replacement for acute aortic dissection in 1. These procedures were elective in 6 patients and emergent in 6. Intraaortic balloon pumps were used in all cases except in two cases with atherosclerotic occlusive disease. Nine (75%) of the patients were weaned from PCPS, and seven (58%) were discharged. There were no complications due to the placement of PCPS except for three episodes of lower leg ischemia. We conclude that PCPS is useful in addressing difficulties in weaning from ordinary cardiopulmonary bypass and there should be further discussion about the limitations of PCPS in cases of severe circulatory failure.     

Adjuvant intra-arterial chemotherapy with gastrin receptor antagonist after hepatic resection in colorectal cancer metastasis

The aim of this study was to determine whether chemo-endocrine therapy after the resection of liver metastasis from colorectal cancer would prevent recurrence in the remnant liver and prolong survival. Eleven colorectal cancer patients underwent hepatic resection for liver metastasis. Subsequently, they were administered Proglumide gastrin antagonist 1,200 mg/day + 5'-DFUR 800 mg/day for 2 years. In seven of them, MMC 6-10 mg and ADM 20 mg were infused intra-arterially every two weeks alternately for one year. In four of them, 5-FU 250 mg/day was infused for seven days continuously intra-arterially every two weeks for one year. Recurrence in the remnant liver occurred in four of 11 patients. All of these patients underwent repeated hepatectomy. The mean disease-free survival in the remnant liver was 37 months and the five-year survival rate was 91%. These results indicate that intra-arterial chemotherapy with gastrin receptor antagonist might be effective for adjuvant therapy in patients with resectable liver metastasis from colorectal cancer.     

Demonstration of 100 Gbps optical packet switching using header processor based on 48-bit longest prefix matching

Wire-rate packet processing and its energy saving for over 100 Gbps speed of line are major issues to be resolved in optical packet switching (OPS) networks. For that purpose, we newly develop a high-speed, deterministic-latency electronic header processor based on longest prefix matching (LPM) for searching optical packet destination addresses (OP-DAs). This paper reports the successful experimental results of electronic header processing based on LPM search of up to 48 bits and optical switching of 100 Gbps optical packets by the use of the header processor. We demonstrate 48-bit LPM-capable optical packet switching. We also demonstrate IP packet transfer and 32-bit LPM-capable optical packet switching. In the latter demonstration, the 32-bit OP-DA of optical packets is directly copied from the 32-bit destination address of Internet Protocol version 4 (IPv4) packets. This result indicates that OPS networks can be deployed with electronic IP networks by the use of integrated network operation between OPS and IP networks.     

A nonlinear receptive field model of the visual system

A nonlinear model for the visual system is proposed in relation to the dependence of receptive field size on luminance. The model is constructed based on the fact that the exponent of Stevens' brightness function varies depending on the target size. The model consists of two stages; the mechanism of spatial summation and the mechanism of 0.5-power in cascade. The mechanism of 0.5-power is responsible for an exponent 0.5 of the brightness function for the point target. The extent of the spatial summation changes depending on the luminance so that the model yields a brightness function with exponent 0.33 for the infinite target of uniform luminance distribution. The model predicts well the signal transfer function of vision, the charactreristics of the suprathreshold spatial summation and the mean luminance dependence of the spatial frequency characteristics for threshold contrast.     

New simple one-end splice loss measurement method using an OTDR for single-mode optical fibre

The letter presents a new simple method using an optical time-domain reflectometer for measuring the real splice loss of single-mode optical fibres from one end of the fibre. Importantly, the method eliminates the difference in backscattering properties of the spliced fibres by subtracting two discontinuities obtained at different wavelengths in the received backscattered power.