bluuebunny/crossref_metadata_2025 huggingface dataset:
Critical Load Concept to Set Restoration Goals for Liming Acidif ied Nor wegian Waters
Authors: Hindar Atle , Henriksen Arne , Sandøy Steinar , Romundstad Ann Jori
Published: March 2003

The concept of critical load is now widely used in the management of acidified waters. In southern Norway, acidification due to long‐range transported air pollutants is one of the most serious environmental problems, affecting an area of 80,000 km2. To preserve and restore biodiversity, Norwegian authorities have chosen liming as a temporary mitigation measure. Critical load estimates were used to estimate the material and financial needs for this large‐scale program. In 1995, more than 2000 localities ranging from small lakes to large salmon rivers were limed. Liming costs in 1996 were $18 million (U.S.). Critical load estimates also formed the basis for international negotiations on sulfur emission reductions, resulting in the second sulfur protocol for Europe and North America in 1994. The critical load estimates indicated that acidified areas in Norway would be reduced to 35,000 km2 after the year 2010, after the commitments of the sulfur protocols are met. By that time, estimated liming costs would be reduced by almost 40%. Lime treatment of River Tovdalselva, with a catchment area of 1885 km2, is probably the largest integrated liming project in the world. In 1990 the critical load was exceeded in 98% of the Tovdalselva catchment. After the year 2010 the exceeded area may be reduced to 44% and the liming cost by two‐thirds.
The Potential for Restoration of Acid‐Damaged Lake Trout Lakes
Authors: Gunn John M. , Mills Kenneth H.
Published: March 2003

This review of long‐term monitoring and experimental manipulation studies from Ontario, Canada, offers encouraging evidence that lake trout (Salvelinus namaycush) populations can be restored to acidified lakes once the problem of acid deposition is solved in North America. Predicting the rate of chemical and biological recovery remains difficult, because there are several limnological attributes (dissolved organic carbon, flushing rate) and biological attributes (acid sensitivity, species longevity, fish community composition) of lake trout ecosystems that can either enhance or delay the recovery process. Some options for managing recovering lakes are also reviewed, including increased pollution controls, liming, hatchery stocking, and harvest controls.
Establishing Tallgrass Prairie on Grazed Permanent Pasture in the Upper Midwest
Authors: Jackson Laura L.
Published: March 2003

The goal of the study was to learn whether native prairie grasses and, eventually, a diverse mixture of native forbs could be incorporated in permanent pastures by means of rotational grazing by cattle. An experiment was established on a farm in northeastern Iowa on a pasture that had never been plowed but had been grazed since the 1880s. One treatment was protected from grazing to test for the presence of remnant vegetation. Andropogon gerardii, Sorghastrum nutans, Panicum virgatum, and Desmanthus illinoensis were introduced in plots first treated with glyphosate; seeds were either drilled (DR) or hand‐broadcast and incorporated by controlled cattle trampling (BT). Seedling establishment and aboveground biomass were followed over 3 years. There was no evidence for remnant native plants on uplands, but seven species of native forbs and four native graminoids flowered in exclosures erected within waterways. D. illinoensis initially established up to 12 seedlings/m2 but had disappeared from all but one plot by the third year. Variation in native grass establishment among replicate plots within treatments was very high, ranging initially from 0.2 to 9.9 plants/m2. In August of the second year, native grasses made up only 8% of the available forage in DR plots and 1% of BT plots. One year later, however, native grasses made up 56% of the available forage in DR plots and 37% of BT plots, and these differences were significant (p= 0.05). A pilot study seeded in late winter (frost seeding) suggested that seeds spread after cattle trampling produced five times more seedlings (2.5/m2) than seeds spread before cattle trampling (0.5/m2). Frost seeding had advantages because it did not require herbicide for sod suppression or tractor access to the site. New plantings could be safely grazed in early spring and late fall, before and after most native grass growth, to offset the negative economic impact of protecting new plantings from burning during the growing season. But this practice precluded subsequent prescribed burning. I propose a strategy for incorporating native wildflowers into the pasture over time with minimum cost.
The Edible Plant Dichelostemma capitatum: Its Vegetative Reproduction Response to Different Indigenous Harvesting Regimes in California
Authors: Anderson M. Kat , Rowney David L.
Published: March 2003

To more thoroughly understand the ecological effects of harvesting geophytes for food by American Indians, an investigation of the ethnobotany and population dynamics of Dichelostemma capitatum (blue dicks), an attractive source of nutrition to many California Indian groups was undertaken. Some cultural groups harvest the corms and replant the cormlets, spare plants, and harvest after seeding to ensure replenishment of seed. Some Indian elders equate judicious harvesting with the maintenance and enhancement of field populations of this geophyte. A field experiment was conducted to determine the degree to which differences in intensity and timing of harvest, with and without replanting of cormlets, have any effect on corm and cormlet production. We found that harvesting at 100% intensity, through digging up all plants and corms, and without replanting cormlets at the seed stage, significantly reduces numbers of corms and cormlets compared to the controls (no harvest). However, harvesting at 50% intensity, through digging up half of all plants and corms at the flowering or seed stages, without replanting cormlets, was not significantly different from the controls (no harvest). The results suggest that harvesting blue dicks corms with a digging stick in the latter way could yield a sustainable level of harvest. Indigenous harvesting and management regimes may offer some of the best examples of long‐term uses and management of the regional flora without detriment to its biodiversity. Restorationists are urged to study and experimentally mimic indigenous disturbance regimes and their ecological effects known to occur historically in various ecosystems. In some cases, areas will greatly benefit from the reintroduction of management and harvesting regimes that authentically simulate ancient indigenous interactions.
Leguminous Trees for the Rehabilitation of Sodic Wasteland in Northern India
Authors: Garg V. K.
Published: March 2003

The study objective was to determine the fuelwood harvesting rotation and magnitude of nutrient accumulation by the sodic tolerant species Dalbergia sissoo and Prosopis juliflora for the rehabilitation of sodic wastelands. Mean annual increment and current annual increment growth of these trees reached a peak in six‐year‐old stands. Leaves dominated the litter of these species and contained high concentrations of most nutrients. N, Ca, Mg, and Fe were present in larger concentrations than other nutrients. Organic carbon additions at harvest after six years averaged 16 Mg ha−1, while soil pH was reduced from 9.8 to 8.6. Exchangeable sodium percentage (ESP) values decreased 65 and 29% under P. juliflora and D. sissoo, respectively, after harvest. These tree species produced significant root spread and deep penetration and were able to rehabilitate sodic soil effectively.
The Mark of Zorro: Effects of the Exotic Annual Grass Vulpia myuros on California Native Perennial Grasses
Authors: Brown Cynthia S. , Rice Kevin J.
Published: March 2003

Native perennial grasses were once common in California prairies that are now dominated by annual grasses introduced from Europe. Competition from exotics may be a principal impediment to reestablishment of native perennial grasses. Introduced annual grasses, such as Vulpia myuros (zorro fescue), are often included with native perennial species in revegetation seed mixtures used in California. To examine the potential suppressive effect of this graminoid, we evaluated the growth and performance of a mixture of California native perennial grasses and resident weeds when grown with varying densities of V. myuros. The annual fescue exhibited a strongly plastic growth response to plant density, producing similar amounts of above‐ground biomass at all seeding densities. Perennial grass seedling survival and above‐ ground biomass decreased and individuals became thinner (i.e., reduced weight‐to‐height ratio) with increasing V. myuros seeding density. V. myuros also significantly suppressed above‐ground biomass and densities of weeds and had a more negative effect on weed densities than on native perennial grass densities. Biomass of native grasses and weeds was not differentially affected by increasing densities of V. myuros. Overall, because V. myuros significantly reduced the survival and performance of the mixture of native perennial grasses and this effect increased with increasing V. myuros density, we conclude that including this exotic annual in native seed mixtures is counterproductive to restoration efforts.
Early Successional Patterns and Potential Facilitation of Woody Plant Colonization by Rotting Logs in Premontane Costa Rican Pastures
Authors: Peterson Chris J. , Haines Bruce L.
Published: March 2003

We examined the size, species, location (x and y coordinates), and microsite inhabited by colonizing trees and shrubs in five abandoned pastures in southern Costa Rica. All woody stems greater than 1 m tall in the pastures were measured and mapped, from the overhanging forest edge to 50 m into the abandoned pasture. Species composition of colonists differed substantially among pastures: Croton draco (Euphorbiaceae) dominated one site, two species of Miconia (Melastomataceae) another site, and Verbesina tapentiensis (Asteraceae) a third site. Site 4 had the highest cover of rotting logs (11%), and a four‐fold greater density of colonizing woody plants than the site with the next highest colonist density. For all species pooled, and for several individual taxa, density was positively correlated across sites with abundance of log microsites.

Four of the six most common woody species in site 4 occurred on logs significantly more often than expected had they been randomly distributed relative to logs. Site 5 had less abundance of logs, but the common Miconia species was again significantly more likely to be found on log microsites. These results strongly suggest that rotting wood microsites facilitate establishment of bird‐dispersed pioneer trees, which in turn could foster regrowth of other forest species.
Test of a Modified Habitat Suitability Model for Bighorn Sheep
Authors: Zeigenfuss Linda C. , Singer Francis J. , Gudorf Michelle A.
Published: March 2003

Translocation of bighorn sheep (Ovis canadensis) is time, labor, and cost intensive and, therefore, high levels of success are desirable. We tested a widely used habitat suitability model against translocation success and then modified it to include additional factors which improved its usefulness in predicting appropriate translocation sites. The modified Smith habitat suitability model for bighorn sheep was 64% accurate in predicting success or failure of 32 translocations of bighorn sheep into the Rocky Mountains, Colorado Plateau desert, and prairie‐badlands of six states. We had sheep location data for 13 populations, and the modified habitat model predicted the areas used by bighorn sheep with greater than 90% accuracy in eight populations, greater than 55% accuracy in four populations, and less than 55% accuracy in one population. Translocations were more successful when sheep were placed into discrete habitat patches containing a high proportion of lambing period habitat (>10% of suitable habitat, p = 0.05), where animals had a migratory tendency (  p = 0.02), no contact with domestic sheep ( p = 0.02), or greater distance to domestic sheep (>23 km, p = 0.02). Rate of population growth was best predicted by area of lambing period habitat, potential area of winter range, and distance to domestic sheep. We retested the model using these refined criteria and the refined model then predicted success or failure of these 32 translocated populations with 82% accuracy.
Soil Water Retention on Gold Mine Surfaces in the Mojave Desert
Authors: Walker Lawrence R. , Powell Elizabeth A.
Published: March 2003

An experimental analysis of soil water retention was conducted on three substrates (an abandoned road, an overburden pile, and a heap leach) created by gold mining activities in the Mojave Desert in southeastern California. We mixed each substrate with straw, and the overburden pile and heap leach with growth medium, then applied surface rock mulch to half the plots in an attempt to increase soil water‐holding capacity for revegetation efforts. For each of the six treatments (controls included) we monitored soil water with time domain reflectometry following both a simulation of a rainfall event and a natural rainfall that occurred immediately following the simulation. Both the simulation and the rainfall increased soil water between 3 and 8%, depending on the substrate. Water retention patterns in the two‐week periods following each water addition were similar between the simulation and rainfall, and among all substrate types as values returned to background (pre‐water) conditions. The abandoned road substrate had higher background water content (16.5%) than the overburden pile (6%) and heap leach (5%). The road also had three times higher organic matter and five times higher soil nitrogen than the other two sites. Soil water retention was improved on the overburden pile by the addition of just surface rock mulch or of straw‐plus‐rock mulch. On the heap leach, increases were found with rock mulch only or with growth medium‐plus‐rock mulch. Rock mulches did not improve soil water retention and straw additions decreased soil water on the abandoned road. Judicious use of soil amendments can improve soil water conditions and improve revegetation efforts on disturbed lands in desert environments.
A Germination and Establishment Field Trial of Themeda australis (Kangaroo Grass) for Mine Site Restoration in the Central Tablelands of New South Wales
Authors: Windsor Donna M. , Clements AnneMarie
Published: March 2003

The current study demonstrated that Themeda australis (R. Br.) Stapf (kangaroo grass), a major understory component of the original grassy Box woodlands in the Central Tablelands of New South Wales, was suitable for use in large‐scale mine rehabilitation. The results of the trial were applied in the mine rehabilitation program. Due to extensive clearing of the woodlands and the introduction of exotic flora and fauna for agriculture, only small remnants of the original flora remain. The final land use of the gold mine is a conservation area free from agricultural pressure. Local native species adapted to the soil conditions and variable climate are highly desirable for the control of soil erosion following mining. Germination and establishment of T. australis on oxidized overburden were examined over 53 weeks. Seed‐bearing mulch was used as both the seeding material and an organic additive to the overburden. The effects of five factors were investigated: time since soil preparation, position within small contour banks, location of contour on experimental slopes, additional water, and rate of seed/mulch application. Direct seeding using the lowest rate of mulch application resulted in the establishment of more T. australis seedlings on new contours than on 15‐month‐old contours. The provision of additional water increased germination and establishment in both old and new contours, but was not essential. Seedling densities were greatest in the middle positions of contour banks up to week seven, but were destroyed during a heavy storm. At the close of the experiment, seedling densities were greater in the top and bottom positions of contours. Although significant slope × rate and age × slope interactions occurred, SNK tests did not reveal any consistent interpretable results.
Earthworm Succession in Afforested Colliery Spoil Heaps in the Sokolov Region, Czech Republic
Authors: Pižl Václav
Published: March 2003

Earthworm communities were studied at six heap sites representing a chronosequence of Alnus glutinosa (black alder) stands (age 3–62 years) and compared with those on an unameliorated heap and in an alder stand (60 years old) on natural soil. Spoil heaps in the open‐cast coal mining area near Sokolov (northwestern Bohemia) were mainly reclaimed using afforestation. No earthworms were found on the virgin heap. Young plots were colonized by euryecious epigeic earthworms (i.e., those living above soil surface), but higher proportions of endogeic species (i.e., soil dwellers), did not appear until after more than 30 years of succession. The density and biomass of earthworms increased from the youngest stand (67 individuals/m2; 5 g/m2) to the older ones (e.g., 407 ind/m2; 13 g/m2 in the 23‐year‐old stand). However, both parameters were low in the oldest stand (35 ind/m2; 3 g/m2), but this may have been the result of extensive soil disturbance. Earthworm populations were often higher in reclaimed sites than in the control alder stand (150 ind/m2; 7 g/m2). However, the community structures were different, with the control being dominated by the litter‐feeding species, Dendrobaena vejdovskyi.
Restoration of a Native Shrubland Impacted by Exotic Grasses, Frequent Fire, and Nitrogen Deposition in Southern California
Authors: Cione Nancy K. , Padgett Pamela E. , Allen Edith B.
Published: March 2003

Natural ecosystems globally are often subject to multiple human disturbances that are difficult to restore. A restoration experiment was done in an urban fragment of native coastal sage scrub vegetation in Riverside, California that has been subject to frequent fire, high anthropogenic nitrogen deposition, and invasion by Mediterranean annual weeds. Hand cultivation and grass‐specific herbicide were both successful in controlling exotic annual grasses and promoting establishment of seeded coastal sage scrub vegetation. There was no native seedbank left at this site after some 30 years of conversion to annual grassland, and the only native plants that germinated were the seeded shrubs, with the exception of one native summer annual. The city green‐waste mulch used in this study (C:N of 39:1) caused short‐term N immobilization but did not result in decreased grass density or increased native shrub establishment. Seeding native shrubs was successful in a wet year in this Mediterranean‐type climate but was unsuccessful in a dry year. An accidental spring fire did not burn first‐year shrubs, although adjacent plots dominated by annual grass did burn. The shrubs continued to exclude exotic grasses into the second growing season, suggesting that successful shrub establishment may reduce the frequency of the fire return interval.
Initial Effects of Prescribed Fire on Morphology, Abundance, and Phenology of Forbs in Big Sagebrush Communities in Southeastern Oregon
Authors: Wrobleski David W. , Kauffman J. Boone
Published: March 2003

Abstract Historic fire return intervals in Artemesia tridentata (big sagebrush) ecosystems have been altered by livestock grazing, fire suppression, and other land management techniques resulting in ecological changes in these areas. Increases in abundance of woody vegetation may be causing declines in native herbaceous understory species. We examined the effects of prescribed fire on the morphology, abundance, and phenology of nine abundant forb (herbaceous dicot) species used selectively by Centrocercus urophasianus (Sage Grouse). In September 1997 prescribed fire was applied to four of eight randomly assigned 400‐ha A.t. wyomingensis (Wyoming big sagebrush) study plots at Hart Mountain National Antelope Refuge, Oregon. Livestock had not grazed experimental plots since 1991. Burning caused morphological changes such as significantly greater numbers of racemes and flowers per raceme in Astragalus malachus (shaggy milkvetch‐Legumoideae) (9 in burn vs. 6 in control; 23 in burn vs. 21 in control, respectively). Also, prescribed burning caused greater numbers of flowers in Phlox gracilis (microsteris‐Polemoniaceae) (57 vs. 13), greater numbers of umbels and umbelletts in Lomatium nevadense (Nevada desert parsley‐Umbellifereae) (4 vs. 2 and 59 vs. 31, respectively), greater numbers of flower heads in Crepis modocensis (Modoc hawksbeard‐Compositae) (32 vs. 21), and greater number of flowers/cm3 in Phlox longifolia (longleaf phlox‐Polemoniaceae) (0.11 vs. 0.06). Crown volume of Crepis modocensis (7,085 vs. 4,179 cm3) and Astragalus malachus (2,854 vs. 1,761 cm3) plants was greater in burned plots than control plots. However, burning resulted in a smaller crown area of Antennaria dimorpha (low pussytoes‐Compositae) (20 vs. 37 cm2). Phenology and time of flowering were also affected by fire. The period of active growth for each species was extended later into the summer in burned plots ( p < 0.01). In addition, Crepis modocensis and Lomatium nevadense flowered 12 to 14 days earlier in burned plots. Fire had no effect on frequency, density, and relative abundance of seven of the nine studied species. Fire reduced the frequency and relative abundance of A. dimorpha and Phlox longifolia and reduced the density of A. dimorpha.
Can Diabetic Neuropathy Be Prevented By Angiotensin‐Converting Enzyme Inhibitors?
Authors: Malik R.A.
Published: March 2003

The incidence of diabetes and its complications is increasing to staggering proportions. Presently the WHO estimates an overall prevalence of 130 million, but by 2025 there will be 300 million individuals with diabetes mellitus. The incidence of diabetic neuropathy approaches 50% in most diabetic populations, there is no treatment, and its consequences in the form of foot ulceration and amputation are financially punishing for health care providers. Attempts to develop treatments have faltered for want of an understanding of the aetiology of diabetic neuropathy. As a consequence, 1999 saw the demise of two further compounds: recombinant growth factor by Roche‐Genentech and the aldose reductase inhibitor zopolrestat, by Pfizer, both had reached phase III clinical trials. They joined an impressive list of at least 30 other compounds which have reached phase III clinical trials and failed to establish efficacy. The need to establish a viable treatment for human diabetic neuropathy is absolutely paramount. To provide a rational answer as to whether angiotensin‐converting enzyme (ACE) inhibitors can prevent human diabetic neuropathy, two major issues need addressing: 1) Does vascular dysfunction cause human diabetic neuropathy? 2) Can ACE inhibitors ameliorate diabetic vascular dysfunction and hence neuropathy? Epidemiological studies support a strong association between neuropathy, retinopathy and nephropathy. Microangiopathy is deemed as the root cause of both nephropathy, and retinopathy and mounting evidence provides support for a vascular basis of diabetic neuropathy. ACE inhibitors appear to correct many of the abnormalities associated with the vascular dysfunction found in diabetes. Thus effective ACE inhibition impacts very positively on cardiovascular outcomes in patients with ischaemic heart disease, particularly in diabetic patients. ACE inhibition also prevents the development and progression of incipient and established diabetic nephropathy and delays progression of background retinopathy. Quinapril improves measures of diabetic autonomic neuropathy. Our recent study has demonstrated a significant improvement in peripheral neuropathy following 12 months of treatment with the ACE inhibitor trandolapril.
A Dual Role Of Erbb2 In Myelination And In Expansion Of The Schwann Cell Precursor Pool
Authors: Garratt A.N. , Voiculescu O. , Topilko P. , Charnay P. , Birchmeier C.
Published: March 2003

Neuregulin‐1 provides an important axonally derived signal for the survival and growth of developing Schwann cells, which is transmitted by the ErbB2/ ErbB3 receptor tyrosine kinases. Null mutations of the neuregulin‐1, erbB2, or erbB3 mouse genes cause severe deficits in early Schwann cell development. Here, we employ Cre‐loxP technology to introduce erbB2 mutations late in Schwann cell development, using a Krox20‐cre allele. Cre‐mediated erbB2 ablation occurs perinatally in peripheral nerves, but already at E11 within spinal roots. The mutant mice exhibit a widespread peripheral neuropathy characterized by abnormally thin myelin sheaths, containing fewer myelin wraps. In addition, in spinal roots the Schwann cell precursor pool is not correctly established. Thus, the Neuregulin signaling system functions during multiple stages of Schwann cell development and is essential for correct myelination. The thickness of the myelin sheath is determined by the axon diameter, and we suggest that trophic signals provided by the nerve determine the number of times a Schwann cell wraps an axon.
P‐0 Glycoprotein Overexpression Causes Congenital Hypomyelination Of Peripheral Nerves
Authors: Wrabetz L. , Feltri M.L. , Quattrini A. , Imperiale D. , Previtali S. , D'antonio M. , Martini R. , Yin X.H. , Trapp B.D. , Zhou L. , Chiu S.Y. , Messing A.
Published: March 2003

We show that normal peripheral nerve myelination depends on strict dosage of the most abundantly expressed myelin gene, myelin protein zero (Mpz). Transgenic mice containing extra copies of Mpz manifested a dose‐dependent, dysmyelinating neuropathy, ranging from transient perinatal hypomyelination to arrested myelination and impaired sorting of axons by Schwann cells. Myelination was restored by breeding the transgene into the Mpz‐null background, demonstrating that dysmyelination does not result from a structural alteration or Schwann cell‐extrinsic effect of the transgenic P‐0 glycoprotein. Mpz mRNA overexpression ranged from 30–700%, whereas an increased level of P‐0 protein was detected only in nerves of low copy‐number animals. Breeding experiments placed the threshold for dysmyelination between 30 and 80% Mpz overexpression. These data reveal new points in nerve development at which Schwann cells are susceptible to increased gene dosage, and suggest a novel basis for hereditary neuropathy.
Zinc finger proteins in the peripheral nerve of adult normal and Trembler mice
Authors: Labatut‐Cazabat Isabelle , Garbay Bertrand , Faveraux Alexandre , Hilmi Souad , Vital Claude , Cassagne Claude , Petry Klaus G.
Published: March 2003

Abstract By using monoclonal antibodies directed against the conserved zinc binding site of zinc finger proteins, we detected 2 prominent zinc finger proteins in rat peripheral nervous system (PNS) during development, and in adult normal and Trembler mice sciatic nerves. The protein of 55 kDa is abundant in adult normal mice and rats, but is weakly expressed in adult Trembler mice. The 29 kDa protein is expressed in neonatal rats and in the Trembler mouse, but is absent in adult rats and mice. These results suggest that the Schwann cell proliferation stage may be associated with the 29 kDa protein expression, and the 55 kDa protein may be implicated in the PNS myelination process.
Aggravated reperfusion injury in STZ‐diabetic nerve
Authors: Nukada Hitoshi , Lynch Chris D. P. , McMorran P. Denise
Published: March 2003

Abstract  The streptozocin (STZ)‐diabetic nerve manifests increased morphological susceptibility to a superimposed acute ischemic injury, and reperfusion injury exaggerates ischemic nerve pathology. To determine whether STZ‐diabetic nerves are susceptible to reperfusion, we evaluated the pathological consequences after 2.5 hours of ischemia followed by 3 and 24 hours of reperfusion in a 20‐week STZ‐diabetic rat sciatic nerve. After 3 hours of reperfusion, endoneurial edema developed in diabetic nerves, whereas non‐diabetic controls showed mild or no edema. Morphometric analysis of endoneurial edema, quantified by the total transverse fascicular area and the point‐count score of endoneurial structureless space, confirmed significantly more reperfusion‐induced edema at thigh and knee levels in diabetic nerves than in controls. Reperfusion caused a significant increase in the number of endoneurial mast cells at the thigh level in diabetic nerves. After 24 hours of reperfusion, there were striking morphological anomalies of myelinated nerve fibers in diabetic nerves, without any observable changes in control nerves. In conclusion, we have demonstrated that STZ‐diabetes exacerbates the morphological change to reperfusion. Diabetes therefore renders the microvasculature more vulnerable to the deleterious effects of ischemia/reperfusion.
Chronic Arsenic Poisoning From Burning High‐Arsenic‐Containing Coal In Guizhou, China
Authors: Liu J , Zheng BS , Aposhian HV , Zhou YS , Chen ML , Zhang AH , Waalkes MP.
Published: March 2003

Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic‐contaminated air and food. Here we report the health effects of arsenic exposure from burning high arsenic‐containing coal in Guizhou, China. Coal in this region has undergone mineralization and thus produces high concentrations of arsenic. Coal is burned inside the home in open pits for daily cooking and crop drying, producing a high concentration of arsenic in indoor air. Arsenic in the air coats and permeates food being dried producing high concentrations in food; however, arsenic concentrations in the drinking water are in the normal range. The estimated sources of total arsenic exposure in this area are from arsenic‐contaminated food (50‐80%), air (10‐20%), water (1‐5%), and direct contact in coal‐mining workers (1%). At least 3,000 patients with arsenic poisoning were found in the Southwest Prefecture of Guizhou, and approximately 200,000 people are at risk for such overexposures. Skin lesions are common, including keratosis of the hands and feet, pigmentation on the trunk, skin ulceration, and skin cancers. Toxicities to internal organs, including lung dysfunction, neuropathy, and nephrotoxicity, are clinically evident. The prevalence of hepatomegaly was 20%, and cirrhosis, ascites, and liver cancer are the most serious outcomes of arsenic poisoning. The Chinese government and international organizations are attempting to improve the house conditions and the coal source, and thereby protect human health in this area.
Salvage Therapy With Thalidomide In Patients With Advanced Relapsed/Refractory Multiple Myeloma
Authors: Tosi P , Zamagni E , Cellini C , Ronconi S , Patriarca F , Ballerini F , Musto P , Di Raimondo F , Ledda A , Lauria F , Masini L , Gobbi M , Vacca A , Ria R , Cangini D , Tura S , Baccarani M , Cavo M.
Published: March 2003

Background and Objectives. Few therapeutic options are presently available for patients with multiple myeloma (MM) who relapse after autologous or allogeneic stem cell transplantation, or for patients who are refractory to conventional chemotherapy and not eligible for salvage high‐dose therapy. Thalidomide, a glutamic acid derivative with anti‐angiogenic properties, has been recently proposed as an effective therapy for patients with advanced refractory disease. The aim of this study was to evaluate the activity of thalidomide in a large series of MM patients. Design and Methods. From October 1999 to January 2001, 65 patients (46 males/19 females) from 8 Italian institutions were treated with thalidomide. Twenty‐six patients had relapsed after autologous stem cell transplantation, either single (n = 12) or double (n= 12); 38 patients had shown disease progression after greater than or equal to 2 lines of conventional chemotherapy, 2 patients had relapsed after allotransplant, one single patient had not received previous treatment. Sixty‐one (93.8%) patients were in stage 111, median beta2 microglobulin was 2.9 mg/L, and median bone marrow plasma cell infiltration was 50%. Thalidomide was initially administered at a dose of 100 mg/day; if well tolerated, the dose was to be increased serially by 200 mg every other week to a maximum of 800 mg/day. Results. The median administered dose of thalidomide was 400 mg/day. WHO grade> II toxic effects were constipation (52%), lethargy (34%), skin rash (11%), peripheral neuropathy (14%) and leukopenia (3%). Sixty patients are presently evaluable for response; of these, 17 (28.3%) showed greater than or equal to 50% reduction in serum or urinary M protein concentration and 11 (18.3%) showed greater than or equal to 25% tumor reduction, for a total response rate averaging 46.6%. After a median of 8 months' follow‐up, 15/28 patients are alive and progression‐free (at 2 to 16 months), 12 patients have relapsed, and 1 patient died of pulmonary edema while still in partial remission. Among pre‐treatment variables that were analyzed for their potential relationship with tumor response, only the concentration of vascular endothelial growth factor (VEGF) in the conditioned media obtained upon culture of bone marrow plasma cells was statistically significant. Plasma cells from patients who responded favorably to thalidomide secreted a significantly lower amount of VEGF than plasma cells from resistant patients (126.45 ± 165 pg/mL vs 227.11 ± 70 pg/mL, p = 0.04). Interpretation and Conclusions. These data confirm that thalidomide is active in patients with advanced relapsed/ refractory MM and represent the basis for ongoing clinical trials aimed at testing the role of this drug as front line therapy for newly diagnosed disease.
Automated And Representative Fascicle Selection For Computer‐Assisted Morphometry Of Myelinated Nerve Fibres In Peripheral Nerves
Authors: Lindemuth R , Mink D , Ernzerhof C , Schimrigk K.
Published: March 2003

We describe an algorithm that permits representative fascicle selection for sample acquisition from the entire cross‐section of a nerve. We calculate the number of fascicles necessary for the acquisition of a given sample volume of nerve fibres from the image magnification, determine the scheme of intrafascicular sampling, and measure the (estimated) nerve fibre density. We start by storing the positions of all fascicles as coordinates of the microscope motor stage. We then recruit the needed fascicles from the file by calling them up out of the storage order with a constant interval, using the quotient of the total number of fascicles and the number of fascicles necessary to obtain the sample size for this purpose. The results obtained on the analysis of 40 specimens of sural and tibial nerves by means of the image analysis system IBAS are reported.
Characterization Of A Delta‐ And C‐Fibers Innervating The Plantar Rat Hindpaw One Day After An Incision
Authors: Pogatzki EM , Gebhart GF , Brennan TJ.
Published: March 2003

Primary hyperalgesia after tissue injury is suggested to result from sensitization of primary afferent fibers, but sensitization to mechanical stimuli has been difficult to demonstrate. In the companion study, sensitization of mechano‐responsive Adelta‐ and C‐fibers did not explain pain behaviors 45 min after an incision in the rat hindpaw. In the present study, we examined mechanical response properties of Adelta‐ and C‐fibers innervating the glabrous skin of the plantar hindpaw in rats 1 day after an incision or sham procedure. In behavioral experiments, median withdrawal thresholds to von Frey filaments were reduced from 522 mN before to 61 mN 2 and 20 h after incision; median withdrawal thresholds after sham procedure were stable (522 mN). Responses to a nonpunctate mechanical stimulus were increased after incision. In neurophysiological experiments in these same rats, 67 single afferent fibers were characterized from the left tibial nerve 1 day after sham procedure (n = 39) or incision (n = 28); electrical stimulation was used as the search stimulus to identify a representative population of Adelta‐ and C‐fibers. In the incision group, 11 fibers (39%) had spontaneous activity with frequencies ranging from 0.03 to 39.3 imp/s; none were present in the sham group. The median response threshold of Adelta‐ fibers was less in the incision (56 mN, n = 13) compared with sham (251 mN, n = 26) group, mainly because the proportion of mechanically insensitive afferents (MIAs) was less (8 vs. 54% after sham procedure). Median C‐fiber response thresholds were similar in incised (28 mN, n = 15) and sham rats (56 mN, n = 13). Responsiveness to monofilaments was significantly enhanced in Adelta‐ fibers 1 day after incision; stimulus response functions of C‐fibers after incision and after sham procedure did not differ significantly. Only Adelta‐ fibers but not C‐fibers sensitized to the nonpunctate mechanical stimulus. The size of receptive fields was increased in Adelta‐ and C‐fibers 1 day after incision. The results indicate that sensitization of Adelta‐ and C‐fibers is apparent 1 day after incision. Because sensitization of afferent fibers to mechanical stimuli correlated with behavioral results, sensitization may contribute to the reduced withdrawal threshold after incision. Spontaneous activity in Adelta‐ and C‐fibers may account for nonevoked pain behavior and may also contribute to mechanical hyperalgesia by amplifying responses centrally.
AGGRESOME FORMATION IN NEUROPATHY MODELS BASED ON PERIPHERAL MYELIN PROTEIN 22 MUTATIONS
Authors: Ryan MC , Shooter EM , Notterpek L
Published: March 2003

Alterations in peripheral myelin protein 22 (PMP22) gene expression are associated with demyelinating peripheral neuropathies. Overexpression of wild type (wt) PMP22 or inhibition of proteasomal degradation lead to the formation of aggresomes, intracellular ubiquitinated PMP22 aggregates. Aggresome formation has now been observed with two mutant PMP22s, the Tr‐ and TrJ‐PMP22 when the proteasome is inhibited. The formation of these aggresomes required intact microtubules and involved the recruitment of chaperones, including Hsp40, Hsp70, and alphaB‐crystallin. Spontaneously formed ubiquitinated PMP22 aggregates were also observed in Schwann cells of homozygous TrJ mice. Significant upregulation of both the ubiquitin‐proteasomal and lysosomal pathways occurred in affected nerves suggesting that two pathways of PMP22 degradation are present. Thus, the presence of aggresomes appears to be a common finding in neuropathy models of PMP22 overexpression and of some point mutations known to cause neuropathy in mice and humans.
DIFFERENCES BETWEEN IN VIVO ABSORPTION AND FLUORESCENCE EXCITATION SPECTRA IN NATURAL SAMPLES OF PHYTOPLANKTON
Authors: Lutz Vivian A. , Sathyendranath Shubha , Head Erica J. H. , Li William K. W.
Published: March 2003

The fluorescence excitation spectrum of live phytoplankton cells represents the portion of light absorbed that has been effectively transferred to chlorophyll a of photosystem II, whereas light absorbed by photoprotective pigments will not lead to fluorescence. Therefore, the in vivo fluorescence excitation spectrum of phytoplankton has been used as a proxy for the action spectrum of phytoplankton in computations of primary production in the ocean. The distribution of chlorophyll a between photosystems, as well as variations in the pathway of energy inside the photosynthetic membrane, can also influence the fluorescence excitation spectrum. In this study, we investigated the contribution of photoprotective pigments to the differences found between in vivo absorption and fluorescence excitation spectra of phytoplankton measured during two cruises: one from Las Islas Canarias to Nova Scotia and another in the Labrador Sea. A comparison of normalized fluorescence excitation and absorption spectra showed high variability in the difference between absorption and fluorescence in the blue region of the spectrum for samples from the two cruises. This difference was not entirely correlated with the concentration of photoprotective carotenoids. In this paper, results are interpreted in terms of differences in pigment composition and known patterns of energy distribution in the photosystems of different algal groups.
MORPHOLOGICAL AND MOLECULAR PHYLOGENIES OF HALIMEDA (CHLOROPHYTA, BRYOPSIDALES) IDENTIFY THREE EVOLUTIONARY LINEAGES
Authors: Hillis Llewellya W. , Engman James A. , Kooistra Wiebe H. C. F.
Published: March 2003

Halimeda Lamouroux 1812 colonizes most benthic euphotic habitats of tropical reefs worldwide; yet, despite its ecological importance and long fossil record, little is known about the evolutionary history of this complex of 33 described species. This report is the first within a developing, comprehensive study of the genus, of which the goals were to determine the major lineages within the genus, compare them with current taxonomic circumscriptions, and begin to evaluate the phylogenetic information that can be gleaned from morphology. We present the first formal phylogenetic analysis based on 23 morphological characters and the last 723 nucleotides of the 3′ end of the rDNA 18S gene including an insertion of approximately 102 bp. Fourteen samples from 10 species representing four sections were included. Independent analysis of both data sets yielded congruent topologies, with the molecular data set offering more resolution. Thirteen of the 23 morphological characters were phylogenetically informative. Holdfast type, cortical branching pattern, and nodal configuration were the key synapomorphies. The 18S rDNA sequence including secondary structural analysis revealed 139 variable positions, of which 58 (42%) were informative. Thirty‐two of the informative positions (55%) were found in the insertion. Three principal lineages were identified corresponding to sections Opuntia and Micronesicae, Rhipsalis, and Halimeda. In the molecular analyses, Flabellia petiolata (Turra) Nizamuddin was included as outgroup but did not resolve relationships among the lineages. Our results provide the basis for detailed phylogenetic and biogeographic studies within specific sections of the genus and for exploration of the evolutionary diversification of large complexes such as H. opuntia and H. discoidea.
TOWARD A NATURAL SYSTEM OF SPECIES IN CHLOROGONIUM (VOLVOCALES, CHLOROPHYTA): A COMBINED ANALYSIS OF MORPHOLOGICAL AND rbcL GENE SEQUENCE DATA
Authors: Nozaki Hisayoshi , Ohta Niji , Morita Eiko , Watanabe Makoto M.
Published: March 2003

The taxonomy of species of Chlorogonium (Volvocales, Chlorophyta) was studied based on comparative light and electron microscopy and DNA sequence data of 23 strains from five major algal culture collections. All of the 23 strains showed pyrenoids under photoautotrophic conditions, but 17 of the 23 exhibited marked reduction in size of pyrenoids, or pyrenoids were absent under photoheterotrophic conditions. The strains could clearly be delineated into six species, C. euchlorum, C. elongatum, C. fusiforme, C. capillatum, C. neglectum, and C. kasakii on the basis of differences in cell shape, number of contractile vacuoles, number and stability of pyrenoids, and ultrastructure of pyrenoids and stigmata. This distinction of species based on morphology was also supported by analyses of rbcL gene sequences. The later strongly showed that each species, C. euchlorum (seven strains), C. elongatum (three strains), and C. capillatum (10 strains), forms a robust clade. Although some morphological differences were noted within different strains of C. euchlorum and C. capillatum, these features were regarded as strain‐specific because they were not reflected in the rbcL gene phylogenies. In addition, the rbcL gene trees strongly suggested that C. neglectum and C. kasakii are closely related to each other, consistent with the similarity of the ultrastructure of pyrenoids and stigmata between the two species. However, C. kasakii can be distinguished clearly from C. neglectum by its multiple pyrenoids in the chloroplast and acute anterior and posterior ends in the vegetative cell.
SYSTEMATIC EVALUATION OF THE GENUS HILDENBRANDIA (RHODOPHYTA): A SYNTHESIS OF TECHNIQUES
Authors: Sherwood A.R. , Sheath R. G.
Published: March 2003

The evolutionary relationships among members of the red algal genus Hildenbrandia have not been well understood for several reasons. For example, the genus contains both marine and freshwater representatives, all of which are non‐calcified and crustose, and few have definitive morphological characters for classification. Hildenbrandia is also assumed to be completely asexual (reproduction by tetrasporangia in marine forms and by gemmae in freshwater populations), and characters of the female gametangial system and post‐fertilization structures are not available for comparative studies. Currently there are 14 marine and five freshwater species and infraspecific taxa recognized within the genus. We used phylogenetic analyses (parsimony, distance and maximum likelihood) of DNA sequences of commonly employed genes (rbcL and 18S rRNA) to examine the evolutionary relationships among representatives of many of these taxa. In addition, we employed morphometrics (principal co‐ordinates and cluster analyses) of several measured characters of these same representatives, as well as all available type specimens, to determine the number of morphologically‐delimited entities within the genus. Thus far our results indicate that some characters traditionally used to distinguish species of Hildenbrandia, such as tetrasporangial division pattern, may not be useful in some cases, and a revision of the taxonomy of the genus will be necessary. Although the marine and freshwater species of Hildenbrandia appear to be well separated in our molecular analyses of European specimens, this trend was not observed for North American specimens. High sequence divergence values were calculated for both the rbcL and 18S rRNA genes of Hildenbrandia, compared to other red algal genera.
AN INCREASE OF ORNITHINE δ‐AMINOTRANSFERASE‐MEDIATED PROLINE SYNTHESIS IN RELATION TO HIGH‐TEMPERATURE INJURY IN GRACILARIA TENUISTIPITATA (GIGARTINALES, RHODOPHYTA)
Authors: Lee Tse‐Min , Chang Yuan‐Chun
Published: March 2003

Changes of proline biosynthesis in relation to high‐temperature (35° C) injury were investigated in Gracilaria tenuistipitata var. liui Zhang et Xia. On exposure to 35° C, the specific growth rate decreased after 5 days while free proline levels increased gradually after 2 days and reached the maximal level on days 4–6 but decreased at day 7. The repair ability of thalli treated at 35° C by measuring the growth rate after transfer to 25° C for another 5 days decreased in thalli that had been grown at 35° C for more than 2 days, and the extent increased as treatment at 35° C was prolonged. After 4 days of treatment at 35° C, the activities of both ornithine δ‐aminotransferase (δ‐OAT; EC 2.6.11.3) and Δ1‐pyrroline‐5‐carboxylate reductase (P5CR; EC 1.5.1.2) increased, but that of γ‐glutamyl kinase (γ‐GK; EC 2.7.2.11) remained unchanged, and that of glutamate‐5‐semialdehyde dehydrogenase (GSAd; EC 1.4.1.3) decreased. The application of 10 μM gabaculine, an irreversible inhibitor of δ‐OAT, at 35° C recovered the growth ability but inhibited the increase of both δ‐OAT activity and free proline level; its effects were reversed by 1 mM proline. G. saliconia, which is relatively tolerant to high temperature, showed a decrease of both δ‐OAT activity and free proline level at 35° C. It seems that a stimulation of proline synthesis from the ornithine pathway via an increase in both δ‐OAT and P5CR activities might be associated with high‐temperature injury in G. tenuistipitata.