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At least 811 records · Page 45Linked to original sources
PubMed2006

[Variation of particulate heavy metals in coastal water over the course of tidal cycle in estuary].

Variation characteristics and its mechanism of particulate heavy metals in coastal water over the course of tidal cycle on the eastern coast of Chongming Island in Yangtze Estuary were studied. Concentrations of Cu, Pb, Fe, Mn, Zn, Cr and Al in suspended particles in bottom water were respectively 184%, 99%, 56%, 62%, 147%, 50% and 45% higher than those in surface sediments influenced by particle size. The concentrations of the reducible Cu, Pb, Fe, Mn, Zn and Al in suspended particles of bottom water were also two to three times of those in surface sediments, but percentages of the reducible fraction of the above-mentioned elements in total metal concentrations in suspended particles were similar to those in surface sediments. High concentrations of particulate heavy metals occurred at the beginning of the food-tide, around the slack water and latter of the ebb tide over the course of five tidal cycles, which was mainly caused by the hydrodynamic conditions. When current velocity increased, the particulate heavy metals resuspended from bottom sediments diluted the perpetual suspended particles in water to a large extent. Environmental factors such as salt, dissolved oxygen and pH in water have little influence on the variations of particulate heavy metals over the course of tidal cycle.

China↗
PubMed2006

[Critical tidal level for planting Kandelia candel seedlings in Xiamen].

Plantable tidal flat is one of the most important factors affecting the survival rate of mangroves seedlings in forestation. In this paper, an experiment was conducted in the tidal zones of Umbrette Natural Reserve in the Dayu Island of Xiamen in May 2003 to investigate the critical tidal level for Kandelia candel forestation. The results showed that the tidal level of 0.99 m above the zero tidal level of the Huang Ocean was not suitable for planting K. candel seedlings, because the waterlogging time at this tidal level was longer than 8 h per-tide-cycle, and the survival rate was lower than 50% . At 1.62 m above the zero tidal level of Huang Ocean, K. candel seedlings had the best growth and the highest photosynthetic assimilation, with a survival rate of 90%. At 1.31 m above the zero tidal level of Huang Ocean, K. candel seedlings could still grow well. It could be concluded that the tidal level of 1.62 m was optimal for planting K. candel seedlings, and the critical tidal level of K. candel seedlings in the coastal areas of Xiamen was not lower than 1.31 m above the zero tidal level of Huang Ocean, where the waterlogging time was not longer than 5.6 h per-tide-cycle.

Biomass↗
PubMed2006

[Behaviors of maricultured hybrid sturgeon].

The study on the behaviors of hybrid sturgeon under mariculture conditions showed that hybrid sturgeon had a stronger endurance to the exposure in air, with 100% and 74.1% of livability after 1 h and 3 h exposure, respectively. The feeding habit of hybrid sturgeon could be domesticated, i.e., all kinds of vegetal proteinic food could be used as feedstuff. Hybrid sturgeon also had a strong hunger resistance. An obvious ingestion rhythm was observed, with two peaks in the morning and evening when breeding in cement pool, and during slack tide and tidal stand when breeding in deep water cage. At the two peaks, the ingestion exceeded 50% of that in the whole day. The hybrid sturgeon in cement pool had the habit of hiding during the day and coming out at night, while that in deep water cage stayed at the base in riptide and swam in slack tide. Hybrid sturgeon had a weaker resistance to riptide and wave than American red snapper, but a stronger resistance than yellow croaker. Hybrid sturgeon could quickly adapt the surroundings, and be a good species to mariculture in deep water cage. The appropriate size of hybrid sturgeon bred in deep water cage should be about 400 g.

Animals↗
PubMed2006

Caseworkers' perceptions of the mental health information needs of persons living with HIV/AIDS.

This qualitative study was the first phase in designing a computer system that provides interactive tailored interventions for management of depressive symptoms in HIV-infected individuals (HIV TIDES). The purposes of the study were to explore caseworkers' perceptions of the mental health information needs of persons living with HIV/AIDS (PLWHA), barriers of accessing mental health information, and possible solutions to fulfilling PLWHA's mental health information needs. A focus group methodology was used to gather perceptions from six experienced community-based workers who provided direct case management services for PLWHA in East Harlem, New York. Data were classified into four main categories: mental health information needs, information sources for mental health concerns, barriers to accessing mental health information, and need for mental health interventions. The results of this study were used to inform the design of HIV TIDES.

Allied Health Personnel↗
PubMedDate not supplied

[Poisoning by paralytic molluscan toxins in Oaxaca].

Toxic Red Tides are caused by marine dinoflagellates which synthesize neurotoxins that accumulate in bivalve mollusks. Upon ingestion, these shellfish can cause paralysis and death. During the month of December, 1989, 99 cases of Paralytic Shellfish Poisoning in the areas of Salina Cruz and Huatulco, Oaxaca, were reported; three of which died. The majority of the cases involved the ingestion of oysters and clams. A short time later, the Red Tide was reported appearing. One hundred and fifteen seafood samples were analyzed through a biologic test in mice to determine the quantity of saxitoxin. Oysters and clams showed levels reaching 4 000 U.R. Laboratory analysis of seawater found very high quantities of Gimnodinium catenatum and Gonyaulax catenella. The control measures consisted of the prohibition of the harvest and sale of all bivalve mollusks as well as a public warning to avoid the consumption of such shellfish.

Animals↗
PubMed1990

A simulation model of water depth in mangrove basin forests.

The construction and validation of a model simulating the water depth within mangrove basin forests is described. Rainfall, water table, water depth and tide data collected from a red mangrove basin forest on Marco Island, FL, was used to estimate model parameters. These included the basin spillover height, evapotranspiration-infiltration rate and the functional relationship of water depth change to rainfall, tide and basin spillover. The model was constructed with LOTUS 123 and calibrated from staff gauge water depth records. The model proved accurate and adaptable. Water depths from the model and staff gauge were correlated highly (r = 0.98). Data from an adjacent black mangrove forest featuring complex wet-dry cycling were used to modify the model. After calibration, the model provided an accurate record of water depths at the site (r = 0.89). This model will provide water depths used in a model of Aedes taeniorhynchus population dynamics.

Aedes↗
PubMed1989

[Histological study on the ossification of the yellow ligament in the thoracolumbar spines of the cadavers. Especially on the early stage of the ossification].

The occurrence process of ossification of the yellow ligament (OYL) was studied radiographically and histologically by using the thoracolumbar spines of the cadavers taken out as en bloc. The subjects were from 44 to 89 years at age (average 66.1 years). After taking roentgenographs, the specimens were sectioned sagittally for histological observations with H-E stain, elastica.van-Gieson stain, safranin-O stain and alcian blue stain. The findings were as follows. 1. Roentgenographically, OYL was evidently found in 6 cases with average age of 71.5 years, while not found in 4 cases with average age of 58.0 years. OYL was more frequently recognized in elderly cadavers. This fact is presumed to be one of the physiological aging processes. 2. Histologically, ossification was found to start in the superior margin of the lamina. Ligament fibers of the yellow ligament attached to the bone tissue piercing through the uncalcified cartilage zone, tide mark and calcified cartilage zone in order. This structure is called enthesis. In the early stage of ossification, cartilage zone became wide being followed by endochondral ossification. Elastic fibers in the cartilage zone became sparse and fine granular calcification was focally found in the uncalcified cartilage zone. Then, these changes also occurred in the ligamentous attachment of the superior lamina, but they were more evident in the superior margin of the inferior lamina. 3. In the advanced stage of ossification, there were a widening of tide mark and an increase of chondrocytes in number. Linear calcified deposits were observed along the ligamentous fibers. Elastic fibers were reduced in the cartilage zone, enlarged and deranged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1978

[Tidal and lunar rhythms (author's transl)].

Behavioral and developmental rhythms of some species inhabiting the intertidal zone of sea-coasts as well as some species of tropical lakes and forests have adapted to environmental cycles which are determined by the moon (the semi-diurnal tides, the semi-monthly cycle of springs and neaps, and the changes in moon-light during the night). The underlying timing mechanisms of these tidal and lunar rhythmus are of different kinds. Some of them belong to the oscillating types of physiological clocks (circa-tidal oscillator, circa-semilunar and circa-lunar oscillator), others may represent an hour-glass type (resulting in a single programming), or they are based on a stochastically influenced control of the duration of activity and rest. The combination of a circa-semilunar oscillator with a circadian oscillator enables an intertidal organism to synchronize its rhythms with an environmental situation which reoccurs only every 15 days at the same time of day (1.3., low-water phase of spring tides). The speculations on true lunar rhythms in humans are discussed.

Animals↗
PubMed1980

Hepatic blood flow: morphologic aspects and physiologic regulation.

The study of the morphology of the hepatic circulation has given evidence that the liver consists of a large vascular delta formed by the confluence of the portal and arterial streams. Their arms, which subdivide the delta into lobar areas, start to run parallel and close to each other when they are still visible to the naked eye. Dwindled down to microscopic size, they become the scaffold of the parenchymal cell masses nestling between the microvessels. The arterioles, as they merge with the sinusoidal and portal channels, assume the role of organizing the microcirculation into units. These units are the vascular core of the structural and functional liver acini. It has now been demonstrated beyond doubt that a PO2 gradient exists in the hepatic vessels and tissues, decreasing from the site of the arteriolar rivulets joining the venous stream toward the site of their common egress via the terminal hepatic venules. The gradient permits the subdivision of the microscopic vascular units into three microcirculatory zones, each of them creating an appropriate microenvironment for specific enzymic and metabolic activity. The microcirculatory shifts in arterial flow from tide to ebb will cause change in the activity of the zones. These are essentially dynamic subdivisions of the metabolic activity in the large liver swamp. Here also start the tiny rivulets forming a green river, the bile stream, that runs in the opposite direction to the portal and hepatic arterial flow. It is to be expected that the quantity and quality of bile carrying important products back to the gastrointestinal area for digestion and absorption of fat are influenced by the tides in portal and arterial flow. All in all, it is evident that vascular morphology is the visual aspect of the dynamic blood flow, thus permitting us to perceive its functional orderliness, and to study the circulatory physiology in the hepatic delta. Means of measurement of hepatic blood flow have been reviewed and its methodological problems have been discussed. It was found that the term "estimated" hepatic blood flow is still justified. Also the relationship between hepatic blood flow and metabolism is not yet clear-cut. The role of the arterial and portal components of the hepatic circulation has been analyzed. There is a reciprocal relationship between arterial and portal volume flow; it is effectuated by the state of constriction or dilation of the mesenteric and hepatic arterioles, both under myogenic control. Portal blood delivers directly to the hepatocyte all water-soluble substances absorbed from the intestines or produced in the intestinal walls. The hepatic artery maintains an appropriate PO2 gradient between the acinar zones and flow of blood against increased tissue resistance; it assures a steady clearance of blood-borne substances, e.g., hormones and endogenous products. Regulation of arterial flow is less neural than neurohumoral; metabolites and bile salts exert additional effects on blood flow...

Animals↗
PubMed1994

Natural products and bronchial asthma.

Two groups of naturally occurring substances, Western red cedar extracts and red tide toxin extracts, have physiologic activity on airway smooth muscle and pose either an occupational hazard in the case of Western red cedar or an exposure hazard in the case of red tide toxins. The mechanisms involved and the specific chemical entities responsible for the action of these substances remain to be fully elucidated.

Allergens↗
PubMed1994

Pancreatic interstitial pH regulation: effects of secretory stimulation.

BACKGROUND: Bicarbonate secretion by pancreatic ducts presumably releases an equivalent amount of acid into the parenchyma. The purpose of this study was to determine the effects of this acid load on pancreatic interstitial pH (pHI). In addition, we examined the relationship of pHI to changes in pancreatic blood flow (PBF), which may be important in acid disposal. METHODS: After validation of a microelectrode method for measurement of pHI in anesthetized cats, the effects of secretin (2 IU/kg intravenously) and cholecystokinin (0.08 microgram/kg intravenously) were examined. PBF was measured simultaneously by the H2 gas clearance technique. RESULTS: Secretory stimulation with secretin produced an increase in pancreatic bicarbonate secretion (146 +/- 23 microEq/15 minutes, p < 0.01). This secretion was associated with a fall in pHI from 7.36 +/- 0.02 to 7.31 +/- 0.02 (p < 0.001), which returned to baseline after 25 minutes. There was an accompanying increase in PBF from 118 +/- 32 to 148 +/- 35 ml/min/100 gm (p < 0.01). In contrast, stimulation with cholecystokinin only slightly increased pancreatic secretion (49 +/- 19 microliters/15 minutes) and had no significant effects on pH or blood flow. CONCLUSIONS: These results suggest that pancreatic secretion of bicarbonate, but not protein, releases H+ into the interstitium, an acid tide comparable to the alkaline tide during acid secretion by the stomach. This interstitial acidosis was accompanied by an increase in PBF. The increase in blood flow may be important in pH homeostasis, contributing to the disposal of this acid.

Animals↗
PubMedDate not supplied

Truncal vagotomy and gastrojejunostomy for chronic duodenal ulcer in India.

BACKGROUND: Insufficient information is available on long term results of truncal vagotomy and gastrojejunostomy since most previous series have relied on functional grading using the Visick scale which possibly both overdiagnoses and underdiagnoses complications. We used endoscopy to assess the results following truncal vagotomy and gastrojejunostomy as well as functional grading and compared them with published results of highly selective vagotomy. METHODS: Two hundred patients were reviewed (5-11 years after truncal vagotomy and gastrojejunostomy) by clinical examination and endoscopy. Completeness of vagotomy was assessed by estimation of the postprandial alkaline tide in the urine and gall bladder using ultrasonography. RESULTS: The ulcer recurrence rate was 15 (7%). Nine (60%) of the recurrent ulcers were asymptomatic and detected only on endoscopy. In all patients with recurrence, the urinary alkaline tide estimation revealed an incomplete vagotomy. Dumping was present in 12%, it was troublesome in 4%, occasional episodes of post-vagotomy diarrhoea in 6% (all in Visick grades I or II) and bile vomiting in 17% (affecting the lifestyle in only 5%). Recurrence and other complications were not related to the experience of the operating surgeon or the type of gastroenterostomy. There was no mortality. Overall, satisfactory long term functional results (Visick grades I and II) were found in 8% of patients. CONCLUSIONS: Truncal vagotomy and gastrojejunostomy still remains the best option in the surgical management of chronic duodenal ulcer. Long term results are good with a relatively low incidence of troublesome complications.

Adolescent↗
PubMed1996

Banning tobacco billboards: The case for municipal action.

In 1994, Baltimore, Md, became the first city to generally prohibit billboards from displaying alcohol and tobacco advertisements. The owner of most of Baltimore's billboards, Penn Advertising, sued, but the federal district court rejected the billboard company's complaint and ruled that the First Amendment had not been violated and that the federal cigarette labeling acts had not preempted the ability of Baltimore to regulate and prohibit billboard cigarette advertising. In the fall of 1995, the federal district court's judgment was unanimously affirmed by the Fourth Circuit Court of Appeals in Richmond, Va. This article analyzes the constitutional and preemption issues and concludes that states and municipalities are on firm legal ground when they restrict the location or placement of publicly visible cigarette advertisements without attempting to regulate the advertisement's content or message. States and municipalities command broad authority to protect children and to shield the public from intrusive forms of advertisement that inflict their messages on a captive audience. A billboard ban thus offers local communities a legal avenue to help curb the rising tide of juvenile smoking without raising taxes, creating bureaucracy or angering smokers.

Advertising↗
PubMed2004

International efforts to control infectious diseases, 1851 to the present.

Many 21st-century observers explain international efforts to control infectious diseases as a function of globalization and recent transformations in international commerce, transportation, and human migration. However, these contemporary global health initiatives can be more fully understood by also exploring the origins of international health organizations and regulations, which were initially dedicated exclusively to stemming the tide of infectious epidemics. This article reviews 3 eras of international approaches to controlling infectious diseases (1851-1881, 1881-1945, and 1945 to the present) and concludes by assessing how nations have a strong fiscal and humanitarian incentive to invest in infectious disease control programs and infrastructures in and beyond their own borders.

Communicable Disease Control↗
PubMed1997

Preparation of single-celled marine dinoflagellates for electron microscopy.

Electron microscopy has been used successfully to study and identify single-celled marine dinoflagellates including parasitic ones and others, such as those that cause red tide. Delicate cells can be preserved for scanning electron microscopy with a combined glutaraldehydeosmium tetroxide mixture that is adjusted for the osmolality of the medium. The protocol allows resolution of fine morphological features. Preservation for transmission electron microscopy can be accomplished with a standard glutaraldehyde fixation and osmium-tetroxide post-fixation in a suitable buffer, but again, the osmolality of the mixture must be adjusted. The protocol allows ultrastructural resolution of vesiculated cells and has been modified for small sample sizes.

Animals↗
PubMed2000

Rapid morphological oscillation of mitochondrion-rich cell in estuarine mudskipper following salinity changes.

Morphological changes in the chloride cells or mitochondrion-rich (MR) cells in the skin under the pectoral fin of the estuarine mudskipper (Periophthalmus modestus) were examined in relation to intertidal salinity oscillation in river mouth. MR cells were distinguished between those in contact with the water (cells labeled with both mitochondrial probe DASPEI and Concanavalin-A, an apical surface marker of MR cells) and those that are not (DASPEI-positive only). After transfer of the fish from seawater to freshwater, no difference in the total MR cell density was observed, but the subpopulation of MR cells that are Concanavalin-A-positive decreased dramatically within 30 min. After 6 hr in freshwater, the fish were returned to seawater; the number of Con-A-positive MR cells increased to the initial levels rapidly. Thus, in seawater, mudskippers seem to open the apical crypts of the MR cells to secrete salt; in freshwater, they close the crypt of the MR cells tentatively, and tolerate hypotonicity until the rising tide. This unique response of chloride cells may also be seen in gills of other estuarine species.

Adaptation, Physiological↗
PubMed1999

Mechanisms underlying the hemolytic and ichthyotoxic activities of maitotoxin.

Maitotoxin (MTX), a putative Ca(2+) channel activator produced by the dinoflagellate Gambierdiscus toxicus showed extremely potent hemolytic and ichthyotoxic activities. Hemolysis of 1% mouse blood cell suspension in saline occurred at 15 nM of MTX. The activity was enhanced six-fold in the presence of 10 microM of Ca(2+) and completely blocked by EDTA2Na, indicating its dependency on external Ca(2+). The MTX-induced hemolysis was little affected by L-type Ca(2+) channel blockers (diltiazem, nifedipine, verapamil) but was strongly inhibited by calmodulin blockers (prenylamine and chlorpromazine) or a phospholipase A2 inhibitor (quinacrine). MTX was mimicked by a calcium ionophore, calcimycin. Based on these results, a series of cellular events triggered by MTX were presumed to occur in the following sequence: increased Ca(2+) entry in cells, activation of calmodulin, promotion of phospholipase A2 activity, and finally destruction of cell membrane resulting from hydrolysis of membrane lipids. The sensitivity of blood cells to MTX varied significantly, dependent on the animal sources. Nucleated blood cells of carps and chickens were 100 times more resistant than those of mammals. LC(50) of MTX to freshwater fish Tanichthys albonubes in Ca(2+) free media (pH 8) was 5 nM but was markedly lowered to 3 pM by raising pH to 8 and increasing Ca(2+) concentration to 2 mM. In a marine environment MTX was 2000 times more toxic to fish than 42-di-hydrobrevetoxin-B (PbTx-3), one of the best known ichthyotoxins of red-tide origins.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2000

Association between favorable neuroblastoma and high expression of the novel metalloproteinase gene, nbla3145/XCE, cloned by differential screening of the full-length-enriched oligo-capping neuroblastoma cDNA libraries.

BACKGROUND: The biology of neuroblastoma (NBL) is at least partly regulated by neurotrophic factors and their receptors. PROCEDURE: To identify novel NBL-related genes that affect growth, differentiation, and programmed cell death of the tumor, we constructed full-length-enriched cDNA libraries by oligo-capping method. RESULTS: Semi-quantitative and quantitative real-time RT-PCR showed that the nbla3145 gene was significantly highly expressed in favorable subset of NBL. The nucleo-tide sequence of nbla3145 revealed that it was a novel member of metalloproteinase, endothelin-converting enzyme, and was the same gene recently reported as XCE. We also cloned nbla3145beta which was a novel truncated form of nbla3145 (or nbla3145alpha). CONCLUSIONS: Our results suggested that nbla3145/XCE plays an important role in regulating growth and differentiation of NBL.

Gene Expression Regulation, Neoplastic↗