Efficient and low-noise single-photon avalanche photodiode for 1.244-GHz clocked quantum key distribution.

An efficient and low-noise 1.244-GHz gating InGaAs single-photon avalanche photodiode (SAPD) was developed for a high-speed quantum key distribution (QKD) system. An afterpulsing probability of 0.61% and a dark count probability per gate of 0.71 ×10-6 were obtained at a detection efficiency of 10.9% for 1.55-µm photons. Furthermore, our SAPD successfully coped with high detection efficiency (≤ 25%) and quite low afterpulsing noise (≤ 3% for ≤ 25% efficiency) at the same time. Its potential was verified using the actual QKD setups installed over a metropolitan area network.

Y1 receptor activation is involved in the effect of exogenous neuropeptide Y on pup growth and the early termination of lactational diestrus in the postpartum rat.

The effect of chronic administration of exogenous neuropeptide Y (NPY) and specific NPY receptor agonists and antagonists on reproductive function was examined in lactating rats. As previously demonstrated in our laboratory, chronic (7-day) intracerebroventricular (i.c.v.) NPY infusion (6 microg/day) from days 8-15 postpartum (pp) caused a significant decrease in milk production and an early termination of lactational diestrus. Similar application of the mixed Y1/Y4/Y5 receptor agonist (Leu31, Pro34) NPY (at 3, 6 and 9 microg/day) reproduced the effect of chronic NPY infusion on milk production in a dose-independent manner. Consistent with this effect, the potent Y1 antagonist/Y4 agonist, 1229U91, given concomitantly with NPY eliminated the decline in milk production. The Y2 receptor agonist, NPY13-36, had no effect on milk production at any of the doses used. Length of lactational diestrus was reduced following administration of the Y2 agonist at 18 microg/day but not at 9 microg or 27 microg/day whereas (Leu31, Pro34) NPY infusion had no effect on this parameter at any of the doses used. However, the group that was treated with NPY plus 1229U91 exhibited the usual length of lactational diestrus, indicating that there is at least some Y1 involvement in the effects of NPY on lactational infertility. To test the possibility that the effects of NPY infusion are mediated through changes in circulating prolactin and progesterone, plasma concentrations of these hormones were measured on day 15 pp in NPY-, (Leu31, Pro34) NPY- and vehicle-treated females. NPY-infused females had lower plasma prolactin concentrations than vehicle-infused dams but progesterone concentrations were similar across groups. Overall, these data indicate that chronic exogenous NPY-infusion in lactating females disrupts milk production and shortens lactational diestrus, most likely through reducing prolactin secretion, and that this effect is mediated via Y1 receptor activity.

Suppression by methylprednisolone of augmented plasma endotoxin-like activity and interleukin-6 during cardiopulmonary bypass.

It has been reported that plasma endotoxin, measured by Limulus amoebocyte lysate assays, markedly increased during extracorporeal circulation (ECC). Therefore, this study was undertaken to see if pretreatment with methylprednisolone 30 mg kg-1 modifies the endotoxaemia and associated increases in plasma cytokines in 17 patients undergoing cardiac surgery requiring ECC. We found that methylprednisolone suppressed significantly the ECC-induced increases in plasma endotoxin, measured by a conventional Limulus amoebocyte lysate assay (Toxicolor), and interleukin-6. Plasma concentrations of endotoxin, measured by a highly specific chromogenic Limulus test (Endospecy test), tumour necrosis factor-alpha and interleukin-1 beta did not increase significantly in either the control or methylprednisolone groups.

[Anesthetic management of a patient with severe hyponatremia].

A 79 year old man, with left femoral neck fracture, was scheduled for an elective operation. After admission, severe hyponatremia probably due to diuretics developed. No neurological abnormalities were observed before surgery. He recovered from anesthesia with no problems. But on the 5th postoperative day he showed transient unresponsiveness. Grand mal seizures were also seen after the serum Na level had recovered to around 130 mEq.l-1. This case shows that in the management of severe hyponatremia, the discrimination between acute and chronic hyponatremia seems to be important.

[Premedication in children--a clinical trial of bromazepam and chloral hydrate suppositories].

We performed a study on 141 pediatric patients between 6 months and 7 years of age who underwent scheduled radical operation for inguinal hernia, to evaluate bromazepam suppository and chloral hydrate suppository as anesthetic premedication for short pediatric operations. The study was also focused on the difference of the effects of the two drugs between two age groups: younger than 5 years, and 5 years and older. The younger age group required a larger bromazepam dose compared with the older age group, and in the younger group even the larger bromazepam dose did not produce a high sedative effect as chloral hydrate. In the older group, bromazepam and chloral hydrate were equally effective. In respect to emergence from anesthesia, bromazepam delayed emergence compared with chloral hydrate after which children awoke from anesthesia very clearly. Thus, chloral hydrate suppository seemed more useful as premedicants in short pediatric operations for its high sedative effect without affecting emergence.

[Heart failure due to rapid right ventricular volume overload in patients with pulmonary hypertension].

We have described three cases of pulmonary artery hypertension (PAH). Two of them developed severe systemic hypotension and cardiac arrest following cardiopulmonary bypass (CPB). Imminent pre-operative right ventricular (RV) failure and subsequent myocardial injury during CPB may have contributed to the insult following CPB. In these cases, RV failure is presumably due to rapid volume overloading, since left atrial pressure (LAP) was essentially unchanged while right atrial pressure (RAP) was markedly elevated during the period of severe hypotension. Furthermore, these events may be attributed to protamine, since the circulatory derangement coincides with its administration. Thus, in these patients with severe PAH, blood transfusion should be carefully titrated under the strict evaluation of both LAP and RAP. Additionally, protamine should be infused at a rate slow enough to avoid concomitant hemodynamic changes. We have also reported a case of over-systemic PAH who was successfully managed intraoperatively by careful monitoring and discreet administration of protamine.