Lessons from Nature

Terrestrial and marine animals, plants, insects, and microorganisms produce a large variety of compounds for the organism's development, daily survival, self-defence, symbiosis, sexual attraction, etc. Certain of these compounds are discussed here, with emphasis not only on their isolation and structure determination, but also on the question as to why they are active. This requires a multidisciplinary approach, for a better understanding of life's processes and nature's mysteries

Application of the Bichromophoric Exciton Chirality Method to the Stereochemical Elucidation of Acyclic Polyols

The recently developed technique of bichromophoric derivatization extends the utility of the exciton chirality method. Selective introduction of two types of exciton chromophores to two different types of hydroxyl groups gives rise to highly characteristic CD curves. Pairs of chromophores are evaluated for two different applications: 1) an oligosaccharide linkage analysis, and 2) elucidation of stereochemistry in acyclic polyhydroxyl compounds with two or more stereocenters. For the latter application, selective introduction of the 9-anthroate chromophore (lemax = 253 nm) at prirnary hydroxyls, together with the p-methoxycinnamate chromophore (,1,m" = 311 nm) introduced at secondary hydroxyls of stereocenters, gives rise to highly characteristic CD spectra. Examination by this method of all diastereomeric n-tetrose and n-peritose diethyl dithioacetals indicates that the anthroate/methoxycinnamate bichromophoric approach is a promising method for assignment of stereochemistry in 1,2,3-triols, 1,2.3,4-tetrols,and other polyhydroxylated compounds

Bilateral Iliopsoas Hematomas under Sedation:A Complication of Postoperative Therapy after Coronary Artery Bypass Grafting

We report a case of bilateral iliopsoas hematomas that occurred during postoperative therapy after coronary artery bypass grafting (CABG). An 81-year-old woman receiving anticoagulant and antiplatelet therapies under sedation after CABG developed sudden anemia and went into shock. Abdominal ultrasonography showed a right retroperitoneal hematoma. She improved gradually with conservative treatment. Many patients with an iliopsoas hematoma complain of low-abdominal pain or femoral neuropathy, but such local signs may be absent under sedation. In anticoagulant and antiplatelet therapies under sedation, when the cause of anemia and shock is not clear, we should suspect peritoneal hematoma and examine the peritoneal space.</p

Effect of hydraulic conditions on manganese accumulation by physical and chemical pathways in chlorinated water distribution system: A preliminary laboratory study

The accumulation of manganese (Mn) in drinking water distribution systems (DWDS) is the main reason for ‘black water’ occurrences at customers' taps. Here, we focused on the impact of hydraulic conditions on Mn accumulation in well chlorinated DWDS, particularly on the physical pathway (i.e., the attachment of particulate Mn to the inner pipe surface) and the chemical pathway (i.e., the autocatalytic oxidation of Mn2+ on the surface of accumulated Mn). Mn accumulation on epoxy resin, a typical lining material for distribution pipes in Japan, was observed in laboratory-scale experiments under different water velocity conditions. The results showed that Mn accumulation was significantly enhanced under higher velocity conditions, which was then fitted with the numerical models describing Mn accumulation by the physical and chemical pathways and the detachment. The rate constants for the physical and chemical pathways had a positive relationship with the flow turbulence in the investigated range, suggesting that hydraulic conditions in DWDS play an important role in Mn accumulation. Effects of Mn speciation and water characteristics on the accumulation process were also simulated under various hydraulic conditions. Based on the obtained results, appropriate countermeasures to control manganese accumulation were then discussed

Labeling studies of photolabile philanthotoxins with nicotinic acetylcholine receptors: mode of interaction between toxin and receptor

AbstractBackground: The nicotinic acetylcholine receptors (nAChRs) and glutamate receptors are ligand-gated cation channels composed of five separate polypeptide chains. A 43 kDa protein of unknown function is noncovalently associated with the cytoplasmic side of nAChR in vivo. The -venoms of many wasps and spiders ccntain toxins that block the activity of these channels. Philanthotoxin-433 (PhTX-433) is a non-competitive channel blocker found in the venom of the wasp Philanthus. We have used a photolabile derivative to investigate how PhTX-433 interacts with nAChRs.Results: A radiolabeled PhTX analog, containing a photolabile group substituted on one of its aromatic rings, photocrosslinked to all five subunits (α, α′, β, γ, δ) of purified nAChR in the absence of the 43 kDa protein. In the presence of the 43 kDa protein, the a subunit was preferentially labeled. Proteolysis of the receptor after crosslinking indicated that the hydrophobic end (head) of the PhTx-433 analog bound to the cytoplasmic loop(s) of the a-subunit. Binding is inhibited by other non-competitive channel blockers such as the related polyamine-amide toxins from spiders and chlorpromazine.Conclusions: These results, coupled with previous structure/ activity studies, lead to a putative model of the binding of PhTx and related polyamine toxins to nAChRs in vitro. The 43 kDa protein appears to influence the orientation of toxin binding. Further binding studies are necessary to confirm the model and to define how toxins enter the receptor and how they are oriented within it. A precise understanding of ligand/receptor interaction is crucial for the design of drugs specific for a particular subtype of receptor

Age-dependent vulnerability to ischemia-reperfusion injury of cyanotic myocardium in a chronic hypoxic rat model

This study evaluated the effects of chronic hypoxia from birth on the resistance of rat hearts to global ischemia, with special emphasis on the duration of hypoxia. Male Wistar rats were housed from birth for 4 weeks or 8 weeks either in a hypoxic environment (FiO20.12) or in ambient air (8 animals for each group). Isolated rat hearts were perfused for 40 min with oxygenated Krebs-Henseleit buffer, subjected to 20 min global no-flow ischemia at 37, and then underwent 40 min of reperfusion. A non-elastic balloon was inserted into the left ventricle and inflated until the pre-ischemic LVEDP rose to 8mmHg. Cardiac function was measured before and after ischemia. The post-ischemic percent recovery of LVDP in hypoxic hearts was worse than in normoxic hearts (4 weeks:55+/-7 vs. 96+/-3%, p0.01;8 weeks:40+/-5 vs. 92+/-4%, p0.01), and was worst in the 8-week-hypoxic hearts. Similarly, the percent recovery of dP/dt in the hypoxic hearts was lower than in the normoxic hearts (4 weeks:51+/-5 vs. 96+/-7%, p0.01;8 weeks:31+/-6 vs. 92+/-7%, p0.01), and was lowest in the 8-week-hypoxic hearts. In conclusion, cyanotic myocardium revealed an age-dependent vulnerability to ischemia-reperfusion injury in a chronic hypoxic rat model.</p

The Incidence of Hyperuricemia and Correlated Factors in Middle-Aged Japanese Men

hyperuricemia-free (less than 7.5 mg/dl of SUA and no medication for hyperuricemia or hypertension) Japanese male office workers aged 30 to 53 yr were followed up for seven successive years with annual examinations, with an average period of observation of 6.4 yr with a standard deviation of 1.6 yr. Subjects who were found to have become hyperuricemic (SUA levels of 7.5 mg/dl or more) or who started medication for hyperuricemia during repeat survey were defined as incidence cases. An analysis by means of the Kaplan-Meier method showed that the incidence of hyperuricemia increased significantly with increases in the body mass index (BMI), systolic blood pressure, diastolic blood pressure, triglyceride level, SUA level, total protein level, white blood cell level, and alcohol intake. From the age-adjusted analysis with the Cox proportional hazards model, the total cholesterol level and hemoglobin A 1c (HbA 1c ) level emerged as significant positive and negative factors for the incidence of hyperuricemia, respectively. Multivariate analysis, excluding the SUA level as a factor in the Cox proportional hazards model, indicated that the BMI, Log triglyceride level, white blood cell level, and alcohol intake were significantly positively associated with the incidence of hyperuricemia. On the other hand, age and the HbA 1c level were significantly inversely associated with the incidence of hyperuricemia. When the SUA level was included as a factor in the model, BMI and alcohol intake remained as independent Received Apr 26, 1999; Accepted Aug 2, 1999 Correspondence to: N. Nakanishi, Department of Social and Environmental Medicine, Course of Social Medicine, Osaka University Graduate School of Medicine F2, 2-2 Yamada-oka, Suita-shi, Osaka 565-0871, Japan factors. Furthermore, the white blood cell level was identified as marginally significant for the incidence of hyperuricemia (p=0.064). In conclusion, obesity and alcohol intake were determined to be independent predictors for the development of hyperuricemia. In addition, the white blood cell level may be a contributory factor. (J Occup Health 2000; 42: 1-7

Calcium Phosphate Composition Affects Ureteroscopic Laser Lithotripsy

The effects of stone composition on transurethral lithotripsy (TUL) have not been sufficiently elucidated. The purpose of this study was to identify how calcium phosphate stone composition impacts TUL. Two hundred eighty-nine cases of semi-rigid and/or flexible TUL for upper urinary tract calculi were reviewed retrospectively. Inclusion criteria were a preoperative assessment by noncontrast computed tomography (NCCT) and a stone composition analysis. Small stones and those without calcium composition were excluded. Stone core radiodensity (SCR) was measured by taking the average of the upper 3 of 5 points in the proximity of the center of the stone on NCCT. Fifty-three patients with calcium phosphate composition (CaP) and 118 patients with calcium oxalate and without phosphate composition were eligible for analysis. SCR was significantly higher in the CaP group (p<0.01). The CaP patient group needed a significantly longer operation time (p=0.014) and more laser energy (p=0.085), and tended to have a lower rate of complete lithotripsy (p=0.096) and higher incidence of postoperative pyelonephritis (p=0.181). Stones containing calcium phosphate are harder, demand more laser energy, and require a longer operating time. NCCT evaluation can estimate stone composition preoperatively, and may be a useful tool for predicting operative outcomes