Live diatom silica immobilization of multimeric and redox-active enzymes.

Living organisms are adept in forming inorganic materials (biominerals) with unique structures and properties that exceed the capabilities of engineered materials. Biomimetic materials syntheses are being developed that aim at replicating the advantageous properties of biominerals in vitro and endow them with additional functionalities. Recently, proof-of-concept was provided for an alternative approach that allows for the production of biomineral-based functional materials in vivo. In this approach, the cellular machinery for the biosynthesis of nano-/micropatterned SiO2 (silica) structures in diatoms was genetically engineered to incorporate a monomeric, cofactor-independent ("simple") enzyme, HabB, into diatom silica. In the present work, it is demonstrated that this approach is also applicable for enzymes with "complex" activity requirements, including oligomerization, metal ions, organic redox cofactors, and posttranslational modifications. Functional expression of the enzymes ß-glucuronidase, glucose oxidase, galactose oxidase, and horseradish peroxidase in the diatom Thalassiosira pseudonana was accomplished, and 66 to 78% of the expressed enzymes were stably incorporated into the biosilica. The in vivo incorporated enzymes represent approximately 0.1% (wt/wt) of the diatom biosilica and are stabilized against denaturation and proteolytic degradation. Furthermore, it is demonstrated that the gene construct for in vivo immobilization of glucose oxidase can be utilized as the first negative selection marker for diatom genetic engineering.

Can nitrogen-13 ammonia kinetic modeling define myocardial viability independent of fluorine-18 fluorodeoxyglucose?

OBJECTIVES: The hypothesis of this study was that evaluation of myocardial flow and metabolism using nitrogen-13 (N-13) ammonia kinetic modeling with dynamic positron emission tomographic (PET) imaging could identify regions of myocardial scar and viable myocardium as defined by fluorine-18 fluorodeoxyglucose (F-18 FDG) PET. BACKGROUND: Uptake of most perfusion tracers depends on both perfusion and metabolic retention in tissue. This characteristic has limited their ability to differentiate myocardial scar from viable tissue. The kinetic modeling of N-13 ammonia permits quantification of blood flow and separation of the metabolic component of its uptake, which may permit differentiation of scar from viable tissue. METHODS: Sixteen patients, > 3 months after myocardial infarction, underwent dynamic N-13 ammonia and F-18 FDG PET imaging. Regions of reduced and normal perfusion were defined on static N-13 ammonia images. Patients were classified into two groups (group I [ischemic viable], n = 6; group II [scar], n = 10) on the basis of percent of maximal F-18 FDG uptake in hypoperfused segments. Nitrogen-13 ammonia kinetic modeling was applied to dynamic PET data, and rate constants were determined. Flow was defined by K1; volume of distribution (VD = K1/k2) of N-13 ammonia was used as an indirect indication of metabolic retention. RESULTS: Fluorine-18 FDG uptake was reduced in patients with scar compared with normal patients with ischemic viable zones (ischemic viable 93 +/- 27% [mean +/- SD]; scar 37 +/- 16%, p < or = 0.01). Using N-13 ammonia kinetic modeling, flow and VD were reduced in the hypoperfused regions of patients with scar (ischemic viable flow: 0.65 +/- 0.20 ml/min per g, scar: 0.36 +/- 0.16 ml/min per g, p < or = 0.01; VD: 3.9 +/- 1.3 and 2.0 +/- 1.07 ml/g, respectively, p < or = 0.01). For detection of viable myocardium in these patients, the sensitivity and specificity were 100% and 80% for N-13 ammonia PET flow > 0.45 ml/min per g; 100% and 70% for VD > 2.0 ml/g; and 100% and 90% for both flow > 0.45 ml/min per g and VD > 2.0 ml/g, respectively. The positive and negative predictive values for the latter approach were 86% and 100%, respectively. CONCLUSIONS: In this cohort, patients having regions with flow < or = 0.45 ml/min per g or VD < or = 2.0 ml/g had scar. Viable myocardium had both flow > 0.45 ml/min per g and VD > 2.0 ml/g. Nitrogen-13 ammonia kinetic modeling permits determination of blood flow and metabolic integrity in patients with previous myocardial infarction and can help differentiate between scar and ischemic but viable myocardium.

Regional distribution and kinetics of [18F]6-flurodopamine as a measure of cardiac sympathetic activity in humans.

OBJECTIVES: To determine whether an increase in cardiac sympathetic activity produced by exercise or sublingual glyceryl trinitrate causes an increased rate of loss of fluorine-18 from the myocardium after intravenous [18F]6-fluorodopamine ([18F]F-DA) in normal volunteers. In addition, to determine the contribution of non-specific uptake of [18F]F-DA in the myocardium in patients with recent heart transplant. PROTOCOL: [18F]F was prepared by direct electrophilic fluorination of dopamine. Nine healthy volunteers each received 1.85 x 10(8) Bq (168-250 micrograms) [18F]F-DA over a period of 3 min and were scanned for 2 h in an ECAT 953/31 tomograph. Three controls were scanned before and after vigorous cycle exercise and two were scanned before and after sublingual glyceryl trinitrate. In addition, two patients (1 and 2 years post-heart transplant) underwent a myocardial perfusion study with ammonia labelled with nitrogen-13 followed by an [18F]F-DA study. RESULTS: There was intense uniform uptake of [18F]F-DA throughout the myocardium in the healthy volunteers. The time course of 18F in the myocardium under resting conditions fitted a biexponential function with mean half-times of 8.0 and 109 min. Vigorous exercise produced a three to fivefold increase in the rate of loss of 18F compared with that when resting. After glyceryl trinitrate, one control had a profound reduction in blood pressure (23%) and twofold increase in the rate of loss of myocardial 18F. The other control had no physiologically significant change in blood pressure, heart rate, or rate of loss of myocardial 18F. Uptake of [18F]F-DA in the two posttransplant patients was confined to a small anterobasal region adjacent to the atrioventricular groove, while blood flow, as measured with [13N] ammonia, was uniformly distributed throughout the myocardium. Partial reinnervation of the myocardium was confirmed by the presence of distinct low frequency spectral peaks of the heart rate power spectrum in both patients. CONCLUSIONS: These results suggest that the uptake of [18F]F-DA reflects the distribution of cardiac sympathetic innervation and that the rate of loss of 18F from the myocardium partially reflects spill over of noradrenaline. The technique may be useful in investigating various cardiac conditions in which the sympathetic system is compromised.

[Aggression in elderly persons with psychiatric disorders]. / Agresja u osób z zaburzeniami psychicznymi w wieku podeszlym.

In recent years aggression among elderly patients with psychiatric disorders has become an area of scientific research. A review of 19 reports, mostly from the USA, shows that a great part of these people demonstrate aggression of varied intensity. It is often a very serious problem for family members and a reason for psychiatric admissions. The aggression-index in this population varies depending on the place of living from 14% in the community, 12%-48% in adult homes to more than 60% in psychiatric hospitals. Nearly half of demented patients show aggressive behaviour in different situations, often of extreme intensity. Some reports suggest aggression to be more common among men, but perhaps only in association with dementia.

[Serum cholesterol, triglycerides, HDL and LDL in aggressive elderly patients with dementia]. / Poziom cholesterolu, trójglicerydów i lipoprotein HDL i LDL w surowicy agresywnych chorych z otepieniem w wieku podeszlym.

Associations were analysed between serum concentrations of cholesterol, triglycerides, HDL and LDL measured after hospital admission, and physical aggression in a sample of elderly patients with dementia (210 women and 160 men). A significant lower serum cholesterol and LDL concentration were found in aggressive patients of both sexes and a significant lower serum triglycerides only in aggressive women. In the subgroups of Alzheimer type dementia, women showed significant lower serum triglycerides, and aggressive men significant lower LDL concentration compared with non-aggressive controls. There were no significant differences in serum HDL between aggressive and non-aggressive patients.

[Aggressive behavior of psychiatric patients among geriatric population]. / Zachowania agresywne pacjentów oddzialu gerontopsychiatrycznego.

Medical documentation of 674 elderly patients of gerontopsychiatric department was studied in order to estimate the frequency of physical aggression in relation to sex, diagnosis of dementia and other psychiatric disorders. This form of aggression was found significantly more often in men (52%) than in women (32%). The prevalence of aggression in men was even more evident in the dementia group (67% men and 39% women). Aggressive acts, with the use of objects as weapons, were aimed mainly against other patients when carried out by women, while male patients more often used the objects to attack the staff. None of the 118 aggressive women injured the attacked person, but 7% of the 160 aggressive men did. The aggression of sexual nature was observed in men (5%) only.

Electric signals in the social behavior of sympatric elephantfish (Mormyridae, Teleostei) from the upper Zambezi River.

Electrocommunication in mormyrid fish from African freshwaters is a challenging research field in neuroethology (Turner et al. 1999). However, virtually nothing is known about electrocommunication within natural mormyrid populations involving sympatric, syntopic species. Here we report on the nocturnal activities and electrocommunication among three syntopic species in a spacious laboratory setting resembling the natural one. Petrocephalus catostoma, Cyphomyrus discorhynchus, and Hippopotamyrus sp. nov. differ characteristically in their behavior, such as in territorial defense, schooling, and joining members of other species during foraging. Comparing social encounters within and between species, the first evidence for interspecific electrocommunication among syntopic species was found.

[Direct sequelae of accidental falls in hospitalized geriatric psychiatry patients]. / Direkte Folgen der Stürze bei hospitalisierten gerontopsychiatrischen Patienten.

Falling is an everyday risk for elderly people, with the consequence of getting hurt. What exactly the dangers are, especially in people with gerontopsychiatric disorders, has hardly ever been mentioned in today's literature. Therefore this report deals with 887 documented fall cases in 758 gerontopsychiatric inpatients during a cumulative time period of 3845 months. The consequences of the falls according to sex and diagnosis of dementia were divided in four categories, depending on how serious the injuries were. About 65 to 71% of the patients don't show any direct consequences, about 10% have serious injuries of which 5% are fractures. There are significantly more dement women than dement men who suffer from fractures. Women over eighty years have significantly fewer serious fall injuries than women in their eighties; the same phenomenon can be observed in men concerning light injuries.

Redistribution of myocardial blood flow with topical nitroglycerin in patients with coronary artery disease.

BACKGROUND: Unlike nonselective coronary vasodilators, nitroglycerin (GTN) is said to exert its primary vasodilatory effect on epicardial conductance vessels. Thus, in experimental models of coronary occlusion GTN appears to preferentially direct blood flow to poststenotic zones of ischemia. This phenomenon has, to date, not been tested in humans. Using positron emission tomography we examined the effect of transdermal GTN on global and regional myocardial perfusion in patients with angiographically proven coronary artery disease. METHODS AND RESULTS: Myocardial perfusion with [13N]ammonia was estimated from dynamic time-activity curves at baseline and 3 hours following application of either a 0.4 mg/h GTN skin patch (n = 10) or a placebo patch (n = 10) in a double-blind parallel design. From resliced cross-sectional images, regional flow, expressed as [13N]ammonia retention, was estimated from 216 myocardial sectors. Ischemia was defined as a significant reduction (> 2 SDs from average counts/pixel in maximally perfused zones) in [13N]ammonia retention within 10 contiguous myocardial sectors coupled with an increase or no change in counts derived from [18F]fluorodeoxyglucose. There was no change in global myocardial blood flow as expressed by [13N]ammonia retention following either placebo (0.61 +/- 0.14 to 0.62 +/- 0.12 min-1) or GTN (0.75 +/- 0.22 to 0.74 +/- 0.19 min-1). Conversely, there was a significant increase in the proportion of blood flow to the ischemic zones with GTN (73.9 +/- 12.6% to 94.9 +/- 17.8%; P < .05). No change in the distribution of blood flow to either ischemic or nonischemic zones was observed with placebo. A slight but insignificant decrease in [13N]ammonia retention in nonischemic zones was observed with GTN (1.01 +/- 0.31 to 0.93 +/- 0.26 min-1). CONCLUSIONS: This study suggests that under resting conditions topical GTN alters myocardial perfusion by preferentially increasing flow to areas of reduced perfusion with little or no change in global myocardial perfusion in patients whose angina is responsive to GTN.

A nursing camp--a multi-agency cooperative effort.

A summer nursing camp for junior and senior high school youth, planned and implemented by a multi-agency advisory group, demonstrates one way to attract future nurses into the profession. To effectively solve the problem of the nurse shortage, the efforts of nurse administrators in education and practice must be coordinated.