Application of artificial neural network modelling to identify severely ill patients whose aminoglycoside concentrations are likely to fall below therapeutic concentrations

OBJECTIVE

Identification of ICU patients whose concentrations are likely to fall below therapeutic concentrations using artificial neural network (ANN) modelling and individual patient physiologic data.

METHOD

Data on indicators of disease severity and some physiologic data were collected from 89 ICU patients who received arbekacin (ABK) and 61 who received amikacin (AMK). Three-layer ANN modelling and multivariate logistic regression analysis were used to predict the plasma concentrations of the aminoglycosides (ABK and AMK) in the severely ill patients.

RESULTS

Predictive performance analysis showed that the sensitivity and specificity of ANN modelling was superior to multivariate logistic regression analysis. For accurate modelling, a predictable range should be inferred from the data structure before the analysis. Restriction of the predictable region, based on the data structure, increased predictive performance.

CONCLUSION

ANN analysis was superior to multivariate logistic regression analysis in predicting which patients would have plasma concentrations lower than the minimum therapeutic concentration. To improve predictive performance, the predictable range should be inferred from the data structure before prediction. When applying ANN modelling in clinical settings, the predictive performance and predictable region should be investigated in detail to avoid the risk of harm to severely ill patients.

Two cases with transient lipoprotein lipase (LPL) activity impairment: evidence for the possible involvement of an LPL inhibitor

Two independent severe hypertriglyceridemic infants with transiently impaired lipoprotein lipase (LPL) activity were observed and the causes were explored. Both infants were female, born prematurely with low birth weight and developed hypertriglyceridemia (Fredrickson type V hyperlipidemia: high VLDL and low LDL/HDL) a few months after birth. While mass levels of their post-heparin plasma LPL and apoprotein C-II (apo C-II), a physiological activator of LPL, were normal, their post-heparin plasma LPL activities were remarkably impaired. Both of their mothers' post-heparin plasma LPL activities were slightly or moderately impaired as well, without a decrease in the LPL mass level. No mutations in the genes for LPL and apo C-II were detected in either patient. In an in vitro study with their serum at onset, we could not detect any distinct circulating inhibitors for LPL. There was no data supporting infection or autoimmune diseases, which might have an impact on LPL activity, during the follow-up period. Levels of their plasma triglyceride (TG) and total cholesterol (TC) were decreased quickly by a dietary intervention with medium-chain triglyceride (MCT) milk and kept normal even after stopping the intervention at around age 1 year. However, their low post-heparin LPL activity persisted and returned to normal at around age 2 years. Their low HDL cholesterol levels persisted even after recovery of the TG and TC levels, although lecithin:cholesterol acyltransferase (LCAT) and cholesterol-ester-transfer protein (CETP), two key enzymes of HDL metabolism, were normal throughout the course. The exact reasons why their post-heparin LPL activities were impaired for a certain period and why their HDL cholesterol levels have remained low are still unclear.

CONCLUSION

Transiently impaired LPL activity with no defect in LPL enzyme induced severe hypertriglyceridemia in infants. The transient occurrence of inhibitor(s) for LPL was proposed.

Actigraph analysis of diurnal motor fluctuations during dopamine agonist therapy

BACKGROUND

Generally, clinicians use rating scales or descriptive writing to characterize diurnal changes in motor signs and symptoms in Parkinson's disease (PD); however, these ratings are subjective and are not easily reproducible.

OBJECTIVE

To examine the usefulness of actigraphy as an objective indicator of akinesia by long-term, continuous measurement of limb motor activity (MA), visualize 24-hour circadian profiles of akinesia, and quantitatively detect cabergoline (CBG) efficacy in both hospitalized patients and outpatients with Parkinson's disease.

METHODS

MA was continuously recorded with a wrist-worn activity monitor (actigraph) in 29 hospitalized PD patients without tremor or abnormal involuntary movements. In another series consisting of 8 outpatients, the response duration of CBG was measured by using averaged actigraphy.

RESULTS

By averaging data gathered every 24 h over several days, it was possible to quantify the circadian patterns of akinesia. These cumulative evaluations of the patients' motor status determined 4 types of akinesia: (1) a wearing-off pattern seen in advanced efficacy stages, (2) stable response, (3) afternoon akinesia, and (4) morning akinesia. Following CBG therapy, the MA increased significantly throughout the daytime, i.e.: by 40% in the morning (8:00 a.m. to 12:00 noon), by 60% in the afternoon (12:00 noon to 6:00 p.m.), and by 60% in the next early morning (from time to get up until 8:00 a.m.).

CONCLUSION

In averaged motor activity, the charting of cumulative evaluations of motor status revealed the long-acting efficacy of CBG in ameliorating existing motor fluctuations throughout the daytime and even promoting sleep benefit in the next morning. Averaged actigraphy is considered to be useful in the quantitative detection of drug responses to parkinsonian akinesia and its circadian variations. This enables titration of the lowest dose of drugs needed to alleviate akinesia.

Phased A-tracts bind to the alpha subunit of RNA polymerase with increased affinity at low temperature

Previously we showed that the expression of a Clostridium perfringens phospholipase C gene (plc) is activated by promoter upstream phased A-tracts in a low temperature-dependent manner. In this paper we characterize the interaction between the alpha subunit of C. perfringens RNA polymerase and the phased A-tracts. Hydroxyl radical footprinting and fluorescence polarization assaying revealed that the alpha subunit binds to the minor grooves of the phased A-tracts through its C-terminal domain with increased affinity at low temperature. The result provides a molecular mechanism underlying the activation of the plc promoter by the phased A-tracts.

[Multiple spinal arteriovenous fistulas occurring at conus medullaris and dura of the sacral region: a case report]

Multiple arteriovenous fistulas (AVFs) of the spine are rare. The authors reported a case of spinal AVFs occurring at two separate sites including the conus medullaris and the dura of the sacral region. A 31-year-old man had a two-week history of progressive low back pain, mild gait disturbance and dysuria. Examination revealed mild motor weakness of both legs, disturbance of superficial sensibility below the L4 dermatome on both sides and dysuria. Sensory disturbance was most obvious in the perianal region, although deep sensibility was not disturbed. Magnetic resonance images (MRIs) of the spine showed many serpentine flow void signals from the lower thoracic region to the sacral region, and spinal arteriovenous malformations were suspected. Selective spinal angiography revealed two AVFs at the separate sites including intradural perimedullary AVF at the conus medullaris and dural AVF at the sacral region. The dural AVF of the sacral region was fed by the left lateral sacral artery and drained through the dilated coronal venous plexus to Th11 level. Embolization with N-butylcyanoacrylate (NBCA) was performed using an endovascular procedure for both AVFs. Although recanalization of the dural AVF of the sacral region was confirmed by angiography two weeks later, it was treated successfully by the surgical approach.

[Perioperative management for radical esophagectomy in a patient with polycythemia vera]

We experienced perioperative management of a 75 year-old patient with polycythemia vera (PV) who underwent transthoracic esophagectomy. After treatment for 14 days of ranimustine and hydroxycarbamid, the preoperative hemoglobin, hematocrit values and platelet count were 17.9 g.dl-1, 58% and 54 x 10(4).mm-3 respectively. During the perioperative period, phlebotomy, elastic stockings, intermittent pneumatic compression, infusion of nafamostat, and early extubation (the day of operation) were performed to prevent deep venous thrombosis. The postoperative course was uneventful and the patient was discharged 34 days after the operation.

Synthesis of 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl)adenine (FddA) via a purine 3'-deoxynucleoside

A synthesis of 9-(2,3-dideoxy-2-fluoro-beta-D-threo-pentofuranosyl)adenine (1, FddA) via a 6-chloro-9-(3-deoxy-beta-D-erythro-pentofuranosyl)-9H-purine (9), which was readily obtained from inosine (5), is described. Fluorination at the C2'-beta position of the purine 3'-deoxynucleoside with diethylaminosulfur trifluoride was improved by the introduction of a 6-chloro group and proceeded in moderate yield. Purine 3'-deoxynucleoside derivatives were also subjected to nucleophilic reactions with triethylamine trihydrofluoride and gave the desired fluorinated nucleoside in good yield. The safety and yield of the fluorination process were greatly improved by the use of triethylamine trihydrofluoride. The influence of the sugar ring conformation and 6-chloro group on the rate of the nucleophilic reaction against elimination are also discussed.

Diabetic ketoacidosis in a case of pheochromocytoma

A 31-year-old woman was admitted to our hospital because of diabetic ketoacidosis (DKA). Ultrasound sonography revealed the existence of the left adrenal tumor and endocrinological examinations established a diagnosis of pheochromocytoma. She had been healthy and there was no evidence for gestational diabetes in her personal history. Characteristic features were not found in her tumor size and the catecholamine levels as compared with typical cases of pheochromocytoma. An overwhelming secretion of catecholamine might suppress insulin secretion, as evidenced by the improvement after the resection of the tumor. However, a significant insulin resistance continued after tumor resection. Obesity and the heterozygosity of beta3-adrenergic receptor gene (Try64Arg) might play a role in insulin resistance, which resulted in DKA at least in part. Literature survey revealed four cases of DKA in the patients with pheochromocytoma including ours, three of which were Japanese. Pancreatic capacity to secrete insulin has been reported to be less than Caucasians, which might be another reason for DKA. Thus, we speculate that both suppressed insulin secretion and insulin resistance deteriorated by obesity or other factor(s) such as abnormality in beta3 adrenergic receptor probably depress beta-cell function resulting in abnormal metabolic imbalance such as DKA.

A questionnaire for neurological symptoms in patients with diabetes--cross-sectional multicenter study in Saitama Prefecture, Japan

This study was designed to investigate the prevalence of neurological symptoms in diabetic patients living in Saitama Prefecture, Japan using 13-item questionnaire. A total of 6472 outpatients with diabetes (3417 men and 3055 women) were recruited from 100 centers. Mean age and mean disease duration were 60.9-year old and 10.4 years, respectively. The questionnaire for monitoring of neurological symptoms was completed at the clinic or hospital visited, and Achilles' tendon reflex, ophthalmologic, blood and urinary examinations were also performed. Of the 6472 patients, 84.8% suffered from a mean of 3.3+/-2.2 neurological symptoms. However, half of these symptoms were not considered to be those of diabetic neuropathy by attending physicians. "Feeling as if a piece of paper is attached to the sole of the foot," "stinging and prickling sensations in feet," and "pain in feet" were the most common symptoms of diabetic neuropathy. The prevalence of diabetic neuropathy as determined by attending physician increased with disease duration and worse control of diabetes. This study found that the majority of diabetics were suffered from neurological symptoms, although half of such symptoms were not considered to be those of diabetic neuropathy by physicians. Furthermore, it is important for diabetics to be diagnosed and treated earlier to prevent progression to severe neuropathic complications by means of optimal glycemic control and use of some chemicals such as aldose reductase inhibitor, and to develop this study to evaluate the efficacy of treatments.

Glycated high-density lipoprotein induces apoptosis of endothelial cells via a mitochondrial dysfunction

Glycation of plasma proteins may contribute to an excess risk of developing atherosclerosis in patients with diabetes mellitus. Although it is believed that high-density lipoprotein (HDL) is nonenzymatically glycosylated at an increased level in diabetic individuals, little is known about a possible linkage between glycated HDL and endothelium dysfunction in diabetes. This study set out to clarify whether glucose-modified HDL affects the function of endothelial cells by examining the apoptosis of cultured human aortic endothelial cells (HAECs) exposed to a glycated-oxidized HDL (gly-ox-HDL) prepared in vitro. Incubation of HAECs with 100 microg/ml of gly-ox-HDL for 48 h showed apoptotic features, such as cell shrinkage, membrane blebbing, and concentration and fragmentation of the nucleus, and the degree of apoptosis was dose-dependent on the glucose used in the preparation of gly-ox-HDL. Stimulation of HAECs with gly-ox-HDL elicited a marked increase in caspase 3 activity and the expressions of active caspase 3 and caspase 9, whereas concomitant treatment with a caspase 3 inhibitor significantly blocked gly-ox-HDL-induced apoptosis of HAECs. The release of cytochrome c into cytosols markedly increased in HAECs during the treatment with gly-ox-HDL. The increased expressions of Bax and Bad were detected in HAECs incubated for 24 h with gly-ox-HDL, but gly-ox-HDL failed to interfere with the expression of Bcl-2 and Bcl-x. Moreover, in vitro experiments with HDL (gly-HDL) glycated in the presence of 2 mM EDTA and Cu(2+)-oxidized HDL suggested that the apoptotic effect of gly-ox-HDL on endothelial cells might be due to an additional oxidative modification of gly-HDL. Taken altogether, additional oxidation of HDL under hyperglycemic conditions may induce endothelial apoptosis through a mitochondrial dysfunction, following the deterioration of vascular function.

Diels-Alder cycloaddition of novel buta-1,-3-diene derivatives possessing a (diethoxyphosphinoyl)difluoromethyl unit

A series of new buta-1,3-diene derivatives possessing a (diethoxyphosphinoyl)difluoromethylene unit at the terminal carbon was prepared to examine the reactivity for Diels-Alder cycloaddition with various representative dienophiles.

Phosphorylation of Mei2 and Ste11 by Pat1 kinase inhibits sexual differentiation via ubiquitin proteolysis and 14-3-3 protein in fission yeast

Fission yeast Pat1 kinase inhibits sexual differentiation by phosphorylating the meiotic inducer Mei2 and the transcription factor Ste11. Here, we show how Pat1 downregulates these proteins. Mei2 is degraded via a ubiquitin-proteasome pathway in a phosphorylation-dependent fashion. The E2 Ubc2 and the E3 Ubr1 are required for this proteolysis. In addition, Pat1 negatively regulates Ste11 via Rad24/14-3-3, thereby repressing mei2+ transcription. The Pat1 phosphorylation sites of Ste11 match the consensus recognition sequence for 14-3-3. Rad24 binds preferentially to phosphorylated Ste11, and this binding results in inhibition of the transcriptional activation capacity of Ste11. Overall, therefore, these results show that Pat1 coordinates concerted molecular mechanisms that govern the sexual differentiation developmental decision.

Two new steroidal derivatives from the fruit body of Chlorophyllum molybdites

Two new steroid derivatives, (22E,24R)-3alpha-ureido-ergosta-4,6,8(14),22-tetraene (1) and (22E,24R)-5alpha,8alpha-epidioxyergosta-6,9,22-triene-3beta-ol 3-O-beta-D-glucopyranoside (2) were isolated from the fruit bodies of Chlorophyllum molybdites (Agaricaceae). The structures were established by spectroscopic and chemical methods. These compounds exhibited cytotoxicity against Kato III cells.

Modulation of reactive oxygen species in endothelial cells by peroxynitrite-treated lipoproteins

Peroxynitrite has been implicated in the oxidative modification of low-density lipoprotein (LDL) particles, and nitrotyrosine residues in the LDL have been detected in atherosclerotic plaques. Studies have suggested that lipoproteins modified by peroxynitrite lead to the onset of atherosclerotic vascular disease. We therefore prepared in vitro lipoproteins oxidatively modified by peroxynitrite (NO(2)-lipoprotein) and investigated the effect of NO(2)-lipoprotein on the viability of cultured endothelial cells. After exposure of a high-density lipoprotein (HDL) to peroxynitrite, some intermolecular complexes of apolipoproteins in HDL were detected on immunoblotting with monoclonal antibodies against apolipoprotein AI and AII, suggesting that nitration of HDL by peroxynitrite causes intermolecular cross-linking of the apolipoproteins in the particles. Treatment with 1 mM peroxynitrite increased the 3-nitrotyrosine level to 28.5 mmol/mol of tyrosine residues in the prepared NO(2)-HDL, as quantitated by HPLC, and the amount in NO(2)-lipoprotein depended on the peroxynitrite concentration. HDL exhibited a shorter lag phase and the reaction plateaued more rapidly than that with LDL. To clarify whether or not NO(2)-lipoproteins affect the function of endothelial cells, we first examined the viability of cultured human aortic endothelial cells (HAECs) exposed to NO(2)-lipoproteins. Incubation with either NO(2)-HDL or NO(2)-LDL significantly reduced the HAEC viability at 72 h. The results of RT-PCR and Western blotting showed that NO(2)-HDL markedly suppressed at 48 h not only the expressed levels of mRNA and protein but also the activity of catalase in HAECs. In contrast, NO(2)-LDL significantly reduced the expression and activity of Cu(2+),Zn(2+)-superoxide dismutase (CuZn-SOD) in the cells. Neither NO(2)-HDL nor NO(2)-LDL interfered with nitric oxide production or expression of cyclooxygenases and NADPH oxidase in HAECs. Increased radical production in NO(2)-lipoprotein-treated HAECs implied that reactive oxygen species such as superoxide anions and hydroxyl radicals may contribute to the mechanism of the toxic effect induced in endothelial cells by NO(2)-lipoprotein. Overall, NO(2)-lipoprotein may lead to deterioration of the vascular function through these endothelial cell responses.

[Transthoracic radical esophagectomy after extensive myocardial infarction]

We experienced the perioperative management of a 47 year-old patient for transthoracic esophagectomy after myocardial infarction. He was admitted to our hospital and diagnosed as having advanced esophageal cancer and he developed extensive myocardial infarction on the day of admission. Revascularization with PTCA was not successful, and circulatory support (IABP) was required for 7 days. Complete occlusion of the right coronary artery and extensive akynesis of the right ventricle occurred. Two months later, transthoracic esophagectomy was scheduled. The patient was monitored with pulmonary artery catheter during perioperative period. The postoperative course was uneventful and the patient was discharged 64 th day after the operation.

Enhanced formation of azoxymethane-induced colorectal adenocarcinoma in gammadelta T lymphocyte-deficient mice

T cell receptor (TCR) gammadelta-positive T lymphocytes, which are localized mostly within the intraepithelial space of intestinal epithelium, have been suggested to play a role in maintaining the normal configuration of intestinal epithelium. However, the role of TCRgammadelta-positive T lymphocytes in the formation and progression of colorectal adenocarcinoma that originates from colorectal epithelial cells remains to be elucidated. In this study, TCRalphabeta and TCRgammadelta-positive T lymphocyte-deficient mice (homozygous TCRa and TCRd-gene knockout mice) and the background wild-type mice were administered azoxymethane, and the formation of macroscopic tumors and microscopic aberrant crypt foci in colorectal mucosa were compared among the three types of mice. Well-differentiated adenocarcinoma appeared 5 months after 5 administrations of azoxymethane (10 mg/kg weight) only in a few TCRd -gene knockout mice and the frequency of the carcinoma-bearing mice was increased at 7 and 9 months after the administration. Aberrant crypt foci were also detected in the colorectal mucosa of TCRd -gene knockout mice to a greater extent than in colorectal mucosa of TCRa-gene knockout mice 1 month after the azoxymethane administration. These results suggest that TCRgammadelta-positive T lymphocytes, which are present mainly in the intraepithelial space, play a role in suppression of the formation and progression of colorectal adenocarcinoma in mice.

Protective effects of clostridium sordellii LT and HT toxoids against challenge with spores in guinea pigs

The protective effects of Clostridium sordellii lethal toxin (LT) and hemorrhagic toxin (HT) toxoids against challenge with spores in guinea pigs were investigated. Purified LT and partially purified HT were obtained from the culture supernatant of C. sordellii strain 3703, and then were treated with formalin to make toxoids. LT. HT and combined LT and HT (LT/HT) toxoid vaccines were prepared by mixing each toxoid with an aluminum phosphate gel as adjuvant. Guinea pigs immunized twice with the respective toxoid vaccines were challenged with spores of strains 3703 or KZ1047. The latter strain does not produce HT. LT toxoid vaccine conferred protection against challenge with strain KZ1047, but not strain 3703, in guinea pigs. All guinea pigs immunized with HT toxoid vaccine died after challenge with spores of either strain. LT/HT toxoid vaccine gave complete protection against challenge with spores of strains 3703 and KZ1047 to guinea pigs. These results suggest that not only LT toxoid, but also HT toxoid, are essential protective antigens of C. sordellii.