Physical soil architectural traits are functionally linked to carbon decomposition and bacterial diversity.

Aggregates play a key role in protecting soil organic carbon (SOC) from microbial decomposition. The objectives of this study were to investigate the influence of pore geometry on the organic carbon decomposition rate and bacterial diversity in both macro- (250-2000 µm) and micro-aggregates (53-250 µm) using field samples. Four sites of contrasting land use on Alfisols (i.e. native pasture, crop/pasture rotation, woodland) were investigated. 3D Pore geometry of the micro-aggregates and macro-aggregates were examined by X-ray computed tomography (µCT). The occluded particulate organic carbon (oPOC) of aggregates was measured by size and density fractionation methods. Micro-aggregates had 54% less µCT observed porosity but 64% more oPOC compared with macro-aggregates. In addition, the pore connectivity in micro-aggregates was lower than macro-aggregates. Despite both lower µCT observed porosity and pore connectivity in micro-aggregates, the organic carbon decomposition rate constant (Ksoc) was similar in both aggregate size ranges. Structural equation modelling showed a strong positive relationship of the concentration of oPOC with bacterial diversity in aggregates. We use these findings to propose a conceptual model that illustrates the dynamic links between substrate, bacterial diversity, and pore geometry that suggests a structural explanation for differences in bacterial diversity across aggregate sizes.

Light microscopic study of degenerating cobalt-filled optic axons in goldfish: role of microglia and radial glia in debris removal.

Labeling severed axons with cobaltous-lysine ultimately leads to the degeneration of their distal segments. The present study was designed to determine whether microglia and radial glia have comparable roles in the elimination of degenerating axons. Another purpose was to determine whether the cobalt could escape from degenerating axons and enter intact neuronal cells. Optic axons were filled with cobaltous-lysine for 1 day and the retinal projections were examined from 1 to 106 days later. Optimal filling was obtained 1 day postlabeling. The number of filled axons in the optic tract was significantly reduced at the 2-day time point, indicating that many axons had disintegrated. Many axons contained large swellings that resembled cells. However, transneuronally labeled neuronal cells were never observed. Labeled, rounded microglia appeared among the degenerating axons at the 3-day time point, and the microglia changed shape at 5 days. They became elongated and manifested many processes. In addition, the microglia began to move toward, and entered, the ventricles and vasculature. Virtually all the labeled debris was removed between 17 and 28 days following the application of cobalt. The rapidity with which the axons were removed suggests that the cobalt accelerates the degenerative process either directly, or indirectly by accelerating the arrival of phagocytic cells. Radial glia appeared to play a smaller role in debris elimination. They took up labeled debris to a lesser degree than microglia and were briefly labeled. Interestingly, radial glia did not take up cobalt when it was injected intracranially and diffused through the brain. A previous claim of an axosomatic retinotectal projection to cells deep in the stratum periventriculare of a teleost fish is reinterpreted to represent cobalt within radial glia.

Topographic disorganization of the optic tracts following long-term optic nerve regeneration: a quantitative image analysis study.

Experiments were designed to find the degree to which regenerated optic axons occupied their previous locations in the optic tracts. Following optic nerve crush and regeneration, either the dorsal, ventral, peripheral, temporal, or nasal part of the retina was ablated. The axons of the remaining retinal ganglion cells (RGCs) were labeled with cobalt. Density of the regenerated dorsal and ventral axons in the dorsal vs. ventral optic tracts was determined digitally. In addition, we determined the density of temporal and nasal axons in the temporal vs. nasal compartments of each optic tract and the density of central axons in the central vs. peripheral compartments of both optic tracts. Regenerated axons were not distributed randomly in the optic tracts. Instead, they were slightly but, significantly biased toward growing through the tract or compartment that they had occupied previously. Still, the pathway specificity exhibited by the regenerated axons was closer to random than it was to the pathway specificity seen in normal animals. Dorsal, ventral, and central RGC axons were significantly better localized to their correct tract or compartment than were temporal or nasal RGC axons. Also, over time, dorsal and ventral axons tended to disappear from incorrectly chosen optic tracts. The slight bias toward choosing the appropriate optic tract or optic tract compartment may be enough to account for the topographic specificity of the regenerated retinotectal projection. Near-randomness of the axonal positions in the tracts argues against the presence of any specific guidance cues in the optic tracts of adult animals. Axonal density was highest in the correct compartment and diminished progressively with increasing distance into the incorrect compartment. Such a gradient of axonal density suggests that regenerating axons "drift" away from their previous positions in the optic pathways.

Axonal redirection at the dorsoventral intraretinal boundary.

Cobaltous-lysine applied to the goldfish optic nerve backfilled retinal ganglion cells and their axons. Confined to the ventronasal and ventrotemporal retina was a small population of retinal ganglion cells whose axons traveled dorsally and parallel to the retinal margin. On reaching the boundary between dorsal and ventral retina, the axons arched, joined radially oriented bundles of axons, and traveled toward the optic disk. Control studies showed that the axons came from retinal ganglion cells rather than from retinopetal cells. The somatic area of retinal ganglion cells (RGCs) with circumferential axons was 30-50 microns, and was similar to that of average ganglion cells. The axons of these cells coursed between the optic fiber and ganglion cell layers or between the ganglion cell and inner plexiform layers. Many somata were displaced slightly toward the inner plexiform layer, but were not really displaced ganglion cells. The aberrant axonal trajectory may be related to the slightly displaced location of the cell. However, ganglion cells that are displaced to the edge of the inner nuclear layer usually have radially coursing axons. We digitized the coordinates of the bending points and the dorsoventral retinal boundary. On average, the bending points occurred within 100 microns of the dorsoventral retinal border. These findings suggest that some molecular, rather than mechanical, factor at the dorsoventral retinal boundary alters the course of the circumferential axons. Furthermore, because there are cells with circumferential axons throughout the ventral retina, the data imply that at least ventral RGC axons avoid mingling with the axons from dorsal RGCs.

Cholestatic jaundice of pregnancy: new perspectives.

Cholestatic jaundice of pregnancy is a condition characterized by pruritus, icterus, or both during pregnancy. A total of 9 pregnancies complicated by cholestatic jaundice are presented. Three of these cases are presented in detail because they reflect complications that can occur with this condition. The literature on cholestatic jaundice is reviewed. This condition has been regarded in the past as benign to the mother and fetus, but these cases and other recent investigations suggest high perinatal mortality and morbidity rates.

Enhanced labeling of mitotic retinal cells with an intraocular [3H]thymidine injection.

Tritiated thymidine ([3H]Tdr) was injected either intraocularly (i.o.) or intraperitoneally (i.p.). Autoradiography showed that more retinal cells were labeled by i.o. than by i.p. injection. Controls showed that the increased number of labeled retinal cells was not related to glioblast proliferation produced by trauma from the i.o. injection. After injection of identical doses, the peak concentration of [3H]Tdr available for incorporation into DNA was about 100 times greater after an i.o. than after an i.p. injection. The effective duration of the labeling pulse in goldfish was 9 times longer for an i.o. than an i.p. injection. This study shows that i.o. delivery of [3H]Tdr is preferable to i.p. injection for efficient delivery of label to proliferating retinal cells.

Technosphere/Insulin--proof of concept study with a new insulin formulation for pulmonary delivery.

Summary.Technosphere/Insulin (TI) is a formulation of regular human insulin and Technosphere, a new drug delivery system for pulmonary administration. The formulation is designed for efficient transport of insulin across the intact respiratory epithelium into the systemic circulation. We have investigated the pharmacodynamic and pharmacokinetic properties of Technosphere/Insulin in five healthy, non-smoking volunteers. In an open, randomized, three-way crossover study, subjects received 5 IU regular human insulin (HI) intravenously, 10 IU HI subcutaneously; and 100 IU TI via inhalation using a small commercially available asthma inhaler. The time action profiles of all three insulin formulations were assessed by the euglycemic glucose clamp technique on three different study days. Glucose infusion rates were monitored from 2 h before until 6 h after insulin administration. Other study measures were serum insulin, serum C-peptide concentrations, and safety parameters. The inhalation of TI was well tolerated. The time to peak action was significantly shorter with both i.v. injection and inhalation, as compared to s.c. (14 +/- 6 min and 39 +/- 36 min vs. 163 +/- 25 min; p < 0.0002 and p < 0.007 (mean +/- SD)). The metabolic effect during the first 3 h after insulin administration was higher with inhaled TI than with HI s.c. (AUC0-180 for glucose infusion rate: 1.94 +/- 0.77 mg/kg * min vs. 1.15 +/- 0.50 mg/kg * min; p < 0.04). Relative and absolute bioavailability for the first 3 h were 26 +/- 12% and 15 +/- 5% respectively (6 h: 16 +/- 8 and 16 +/- 6%). We conclude that inhalation of TI leads to a rapid onset of metabolic action resembling the effect observed with i.v. administration of regular HI. Despite the use of a common asthma inhaler, bioavailability over the three hour prandial period was substantially greater than with other reported pulmonary systems. Therefore, inhalation of Technosphere/Insulin may become a suitable and attractive alternative for prandial insulin delivery, especially for patients with type 2 diabetes mellitus.

Prental diagnosis and subsequent team approach to the management of omphalocele.

The diagnosis of omphalocele can now be made in the prenatal period with the use of ultrasound and the intraamniotic injection of radiopaque contrast material. By diagnosing omphalocele prior to birth a combined obstetric, neonatal and pediatric surgical approach can lead to a successful outcome of pregnancy and subsequent development of a normal infant.

The effects of a six-week, low-intensity Nautilus circuit training program on resting blood pressure in females.

Twenty-six healthy, untrained females were studied to determine the effects of a low-intensity Nautilus circuit training program on resting systolic and diastolic blood pressure. Thirteen subjects who were in good health with no personal history or family history of cardiovascular disease participated in a six-week training program on the Nautilus circuit (14 exercises) and trained at 30% of maximum. Measurements in blood pressure were made before, during (three times per week) and after the study. Another group of 13 females served as controls. An attempt was made to determine if strength increase (due to circuit training) would have an affect on reducing resting systolic and diastolic blood pressure. The following changes occurred in the treatment group: (1) resting systolic blood pressure dropped significantly (from 113 to 99 mmHg) after training and (2) diastolic blood pressure dropped significantly from (70.9 to 62.0 mmHg) after training. However, there were no differences in these decreases between the exercise and control groups. The investigators concluded that low-intensity, resistive training should not increase blood pressure in white, healthy females, ages 18 to 28 years.

The multiskilled health practitioner movement: where are we and how did we get here?

Multiskilled practitioners have been in health care settings for a long time. The form multiskilled practitioners have taken has varied with the cultural, socioeconomic, and technological constructs of the times. Some multiskilled practitioners have come and gone while others, such as the medical assistant and physician assistant, have remained. The complexity and sophistication of skills being combined have increased over time as have the degree level and opportunities for dual certification. Skills have been combined both across and within disciplines. There is currently a greater number and variety of formal programs to prepare multiskilled health practitioners in educational institutions and health care facilities, and more informal on-the-job training efforts than ever before--and they are increasing. Employment of multiskilled personnel has become a survival strategy for health care institutions in this current era of cost containment. Multiskilled allied health practitioners with basic nursing skills (ie, LPN level) may also provide one step toward a solution to the nursing personnel shortage being experienced by some health care facilities. The catchword for multiskilled has become not "whether," but "how."15 It is to everyone's benefit to learn from the efforts of those with experience in implementing the multiskilled health practitioner concept for both national and international application. The National Multiskilled Health Practitioner Clearinghouse intends, through its publications, services, and resource files, to serve as the cornerstone upon which the information from those with experience can be reposited and disseminated.

Marketing health promotion to corporations: overcoming the cost/benefit problem through a customer orientation.

Many corporations are reluctant to offer health promotion programs for their employees because there is no concrete evidence that the financial benefits will be greater than the capital outlays necessary for implementation and operation. This presents a major problem when marketing health promotion programs. The problems with cost/benefit analysis in the health promotion field are first identified. Then, the weaknesses in the health promotion research are outlined. Finally, marketing philosophy and strategies which avert these problems are presented. Health promotion programs offered at the worksite are increasing in number (Forouzesh and Ratzker, 1985). Much of this growth is a response on the part of corporations to the causes of death in the United States and the increases in health care costs. In 1987 diseases of the heart and blood vessels were the leading cause of death in the U.S. with an estimated 976,706 deaths (American Heart Association, 1989). This figure is more than twice the second leading cause of death, cancer. It was also determined that more than one-fourth of the American population suffered from some form of cardiovascular disease. However, death is not the only expense to society. It was estimated that cardiovascular disease cost $94.5 billion in 1990 (American Heart Association, 1989). U.S. corporations directly or indirectly were responsible for paying much of this cost. Therefore, corporations are searching for solutions to these problems. Health promotion programs offered at the worksite are one potential approach to decrease health care costs and deaths due to cardiovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluating research in worksite health promotion.

Critical review of studies published in the area of worksite health promotion is an important skill for health promotion professionals. Most studies have some weaknesses which make it difficult to draw meaningful conclusions. Therefore, it is important to consider the research design of these studies. By accurately evaluating the conclusions of health promotion investigations, health promotion professionals will be able to make better recommendations for effective program development.

Fitness and health promotion in Japan.

Health promotion efforts in Japan are progressing much as they are in the United States. However, as Japan has different health problems and a different business culture, health promotion efforts in Japan differ from those in the United States. This paper will examine the major causes of death in Japan, prevalent lifestyle problems, cultural differences, types of health promotion programs which are offered, and program effectiveness. By making comparisons between two culturally different countries health promotion professionals will be able to understand their own programs better and develop new ideas for future programming efforts.

The energy costs of a modified form of T'ai Chi exercise.

BACKGROUND: Alternative strategies for exercises that provide both training and relaxation benefits are optimal for persons with very low functional capacities who also are at high risk for complications. T'ai Chi C'hih, a modified form of traditional T'ai Chi, is a series of slow balanced movements and breathing promoted to increase energy levels and induce relaxation. OBJECTIVES: To estimate the energy costs and cardiovascular effects of T'ai Chi C'hih. Measured energy costs of specific activities can assist with safe exercise prescription for individuals with very low energy reserves. METHODS: A convenience sample (n = 26) of healthy adults participated in this study, which involved completion of surveys to estimate functional capacity and exercise participation, training in a select series of nine T'ai Chi C'hih movements, and oxygen consumption testing while movements are performed. Movements involving front to back and lateral moves of the lower extremity, full shoulder range of motion of upper extremity, and deep forced inhalation and stepped exhalations were performed at slow to fast cadences in sitting and standing positions. The Human Activity Profile was used to estimate lifestyle energy consumption. Exercise participation was quantified as Kcal/Kg(1) expended per week. RESULTS: Metabolic equivalents (METs) for sitting T'ai Chi C'hih movements were estimated to be 1.5 +/- 0.17 and 2.3 +/- 0.34 for slow standing, and 2.6 +/- 0.47 for fast standing. Mean maximum heart rates ranged from 43% to 49% of predicted maximum heart rates. Mean increases in both systolic and diastolic blood pressures over resting were 8%. Mean METs of breathing exercises ranged from 3 to 3.6. There were no differences in responses to the movements by gender or experience with T'ai Chi exercise. CONCLUSION: The movements used to perform T'ai Chi C'hih require energy expenditure comparable with that for activities of daily living and for low level exercises currently recommended for persons with low exercise tolerance. Therefore, T'ai Chi C'hih may be an alternative approach to health promotion in many populations with chronic disease.

Causal basis of gravity stimulus nullification by clinostat rotation.

Using appropriate clinostat rotation methods, it has been shown that increases in root growth and geotropic curvature of oat coleoptiles are related to and explained (within the limits of auxin economy) by increased rates of plant respiration imparted by nullification of the gravitational stimulus. Increased respiration with decreased gravitational stimulus, in turn, is explained by increased uniformity in intracellular distribution of metabolically active graviprecipitable particles.Oat seedlings grown with nullification of the gravitational stimulus show a more uniform distribution of graviprecipitable protoplasmic inclusions. Respiration involves reactions between particles of sufficient mass to be precipitated in 1 x g unidirectional force field and particles of such size that they are distributed throughout the protoplasm due to thermal energy. When plants are grown without nullification of the gravitational stimulus, graviprecipitable protoplasmic inclusions tend to accumulate in the lower portions of the cells. Respiration rates are consequently limited due to a relatively low concentration of the smaller particles in the region of high concentration of the larger particles. Distribution of the larger particles throughout the protoplasm negates the reaction rate limiting effects of these intracellular concentration gradients.It has been shown using starch particles to index graviprecipitation of intracellular particles that enhancement of respiration by nullification of the gravitational stimulus may be induced, maintained, discontinued, and reinduced by treatments which concomitantly result in the more uniform distribution of graviprecipitable protoplasmic inclusions, the maintenance of this uniform distribution, the discontinuation of this uniform distribution and its reinduction.The degree of uniformity of intracellular particle distribution in response to treatments only partially nullifying the gravitational stimulus is shown wholly consonant with growth responses of roots and coleoptiles when the growth is measured as the expression of increased respiration in the absence of auxin limitation.The findings collectively indicate that gravity sensing by plants is broadly based on the physicochemical relationship between particle distribution and the expression of respiratory metabolism as growth.

Simulated Low-gravity Environments and Respiratory Metabolism in Avena Seedlings.

Using horizontal and vertical axis clinostats and sand-grown oat seedlings (Avena sativa), it was found that horizontal clinostat rotation at 2 rpm increased respiration and inorganic and organic phosphorus content of seedlings. Increased coleoptile geotropism and root growth are attributed to rotational nullification of the directional component of the gravitational stimulus. These growth modifications are mechanistically explicable by the relationship between plant metabolism and auxin concentration in these organs.

Circadian rhythms of Blattella germanica L. as determined by microcalorimetry.

Circadian rhythms of the male cockroach Blattella germanica L. have been observed in thermograms recorded from a microcalorimeter. These endogenous rhythms developed in unentrained individuals after 2 or more 24-h periods without light at 20 degrees C in the microcalorimeter. The rhythm can also be entrained with standard conditions LD 12:12 for a 3-day period.