Nutrient and hydrology effects on soil respiration in a northern Everglades marsh

Microbial respiration in peat and overlying plant litter, as influenced by water level and phosphorus enrichment, was evaluated for an Everglades (Florida, USA) marsh ecosystem by measuring CO2 and CH4 release from soil-water microcosms. Intact cores of peat, overlying plant litter, and surface water were collected at seven locations in cattail (Typha domingensis Pers.) and sawgrass (Cladium jamaicense Crantz) stands along a phosphorus (P) enrichment gradient in Water Conservation Area 2A (WCA-2A). Each soil-water microcosm was outfitted with a controlled air circulation system whereby outflow gas from the headspace could be analyzed for CO2 and CH4 to determine flux of C from the soil-water column to the atmosphere. Gaseous C flux was determined for flooded conditions (10-cm water depth) and for water levels of 0, 5, 10, and 15 cm below the peat surface. Overall, decreasing water level resulted in significantly increased C flux, although rates were significantly higher under flooded conditions than under nonflooded, saturated-soil conditions, presumably due to O2 availability associated with algal photosynthesis within the litter layer in the water column. Carbon flux decreased significantly for sites increasingly distant from the primary hydrologic and nutrient inflows to WCA-2A. The microcosm study demonstrated that the C turnover rate was significantly increased by accelerated nutrient loading to the marsh, and was further enhanced by decreasing water level under drained conditions. Our results also demonstrated that photosynthesis within the water column is a potentially important regulator of C mineralization rate in the litter layer of the marsh system.

Reliability of pre-operative biopsies in the histological grading of colorectal adenocarcinomas

BACKGROUND

Management of colorectal cancer depends on many patient and tumour variables. Decisions are sometimes based on the histological grade of tumour as assessed by initial biopsy. This retrospective study looked at the reliability of grading colorectal cancer from pre-operative biopsies.

METHODS

118 patients with a diagnosis of colorectal cancer, who had adequate pre-operative biopsies, were included in the study. A single consultant histopathologist re-examined all the preoperative biopsy slides, but was blinded to the final grading of the resection specimen.

RESULTS

Of the 118 resection specimens, 41 were graded well-differentiated, 52 moderately differentiated and 25 poorly differentiated. When compared with postoperative grading, 37 (31%) initial biopsies were undergraded, 49 (43%) were correctly graded and 32 (26%) were overgraded.

CONCLUSIONS

These results suggest that the histological grading of pre-operative specimens is inaccurate and should be used with caution to determine treatment. The difficulty with grading pre-operative biopsies in colorectal cancer may be owing to a lack of specific criteria such as is used in, for example, breast cancer.

Monocyte apoptosis in dialysis patients is Fas ligand-mediated

BACKGROUND

The mononuclear phagocyte system plays an important role in host defense. Since dialysis patients have been reported to show enhanced leukocytes apoptosis, we evaluated the mechanism of increased apoptosis of monocytes in dialysis patients.

METHODS

Apoptotic studies were carried out on monocytes isolated from dialysis patients as well as healthy subjects. The effect of dialysis sera and membranes was evaluated on monocyte apoptosis as well as monocyte expression of proapoptotic proteins such as Fas and FasL. To confirm the role of FasL, we evaluated the effect of activated secretory products on T cell apoptosis. In addition, we studied FasL content of dialysis sera and supernatants of activated monocytes.

RESULTS

Monocytes isolated from dialysis patients (MDP) showed a greater magnitude of apoptosis when compared to monocytes isolated from healthy subjects (MHS) (MHS, 3.6 +/- 1.1% vs. MDP, 24.3 +/-1.4%). Sera of hemodialysis patients (SHD) promoted (p < 0.001) apoptosis of MHS when compared to pooled control sera (HPS) (HPS, 0.8 +/- 0.5% vs. SHD, 11.5 +/- 0.5% apoptotic cells/field). Dialysis membranes, cellulose acetate membranes in particular, promoted monocyte apoptosis. Interestingly, anti-FasL antibodies partly inhibited dialysis sera-induced monocyte apoptosis. Dialysis membranes also modulated monocyte expression of both Fas and FasL. Secretory products of activated monocytes also promoted T cell apoptosis. Dialysis sera and activated monocyte secretory products showed increased FasL content.

CONCLUSIONS

These results suggest that dialysis patients have an increased rate of monocyte apoptosis, which is mediated through a uremic milieu (serum factors). One of these serum factors seems to be FasL. In addition, dialysis membranes seem to promote apoptosis independent of the uremic milieu. The present study provides a mechanistical insight into the enhanced apoptosis of monocytes in dialysis patients.

Composition and function of sulfate-reducing prokaryotes in eutrophic and pristine areas of the Florida Everglades

As a result of agricultural activities in regions adjacent to the northern boundary of the Florida Everglades, a nutrient gradient developed that resulted in physicochemical and ecological changes from the original system. Sulfate input from agricultural runoff and groundwater is present in soils of the Northern Everglades, and sulfate-reducing prokaryotes (SRP) may play an important role in biogeochemical processes such as carbon cycling. The goal of this project was to utilize culture-based and non-culture-based approaches to study differences between the composition of assemblages of SRP in eutrophic and pristine areas of the Everglades. Sulfate reduction rates and most-probable-number enumerations revealed SRP populations and activities to be greater in eutrophic zones than in more pristine soils. In eutrophic regions, methanogenesis rates were higher, the addition of acetate stimulated methanogenesis, and SRP able to utilize acetate competed to a limited degree with acetoclastic methanogens. A surprising amount of diversity within clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) genes was observed, and the majority of DSR sequences were associated with gram-positive spore-forming Desulfotomaculum and uncultured microorganisms. Sequences associated with Desulfotomaculum fall into two categories: in the eutrophic regions, 94.7% of the sequences related to Desulfotomaculum were associated with those able to completely oxidize substrates, and in samples from pristine regions, all Desulfotomaculum-like sequences were related to incomplete oxidizers. This metabolic selection may be linked to the types of substrates that Desulfotomaculum spp. utilize; it may be that complete oxidizers are more versatile and likelier to proliferate in nutrient-rich zones of the Everglades. Desulfotomaculum incomplete oxidizers may outcompete complete oxidizers for substrates such as hydrogen in pristine zones where diverse carbon sources are less available.

Short-term and long-term follow-up of abdominal sacrocolpopexy for vaginal vault prolapse: initial experience in a district general hospital

The aim of this study was to evaluate the short-term and long-term outcome with patients' satisfaction of abdominal sacrocolpopexy performed on our initial 11 patients for vaginal vault prolapse. All patients included in this study underwent surgery at a district general hospital and was performed by one experienced clinician (co-author). A retrospective analysis was performed on all 11 consecutive women who underwent abdominal sacrocolpopexy for vaginal vault prolapse between September 1996 and January 1997 and were followed-up at 6 months and at 5-year intervals. Our initial experience reveals that abdominal sacrocolpopexy is a safe and effective method in the treatment of posthysterectomy prolapse of the vaginal vault. It is associated with a low incidence of intraoperative and immediate postoperative complications and recurrent vault prolapse. Latent stress incontinence may be unmasked and preoperative urodynamic evaluation is therefore recommended. Our study also agrees with the other studies in that co-existent cystocoele, rectocoele and enterocoele should be corrected at the same setting. Following this series we have modified our technique to reduce postoperative complications such as graft erosion, which is being analysed separately. It finally concludes that this operation should be considered by every gynaecologist and that it can be performed in any district general hospital.

Narrow-waveband reflectance ratios for remote estimation of nitrogen status in cotton

Tailoring nitrogen (N) fertilizer applications to cotton (Gossypium hirsutum L.) in response to leaf N status may optimize N use efficiency and reduce off-site effects of excessive fertilizer use. This study compared leaf and canopy reflectance within the 350 to 950 nm range in order to identify reflectance ratios sensitive to leaf chlorophyll (Chl), and hence N status, in cotton. Plants were grown outdoors in large pots using half-strength Hoagland's (control) solution until some three-row plots received a restricted supply of N. Treatments comprised control, 20% of control N at first flower bud (square) onward; 0 and 20% of control N at first flower onward; and 0% of control N at fruit-filling onward. Despite leaf N values ranging from 51 to 19 g kg-1 across treatments and sampling dates, a weak correlation was obtained between Chl and N (r2 = 0.32, df = 70). In general, N stress led to increased reflectance at 695 +/- 2.5 nm (R695) and decreased reflectance at R410, and changes in leaf N were best correlated with either R695 or R755 in leaves and either R410 or R700 in canopies. The strongest associations between leaf constituent and canopy reflectance ratio were Chl vs. R415/R695 (r2 = 0.72), carotenoids vs. R415/R685 (r2 = 0.79), and N vs. R415/R710 (r2 = 0.70). The R415 measure appears to be a more stable spectral feature under N stress, as compared with more pronounced changes along the reflectance red edge (690-730 nm). Multiple regression identified a three-waveband canopy reflectance model that explained 80% of the variability in leaf N. Results indicate that remote sensing of N status in cotton is feasible using narrow-waveband reflectance ratios that involve the violet or blue region of the spectrum (400 to 450 nm) and the more commonly featured red-edge region.

Bioavailability of organic phosphorus in a submerged aquatic vegetation-dominated treatment wetland

Enzymatic hydrolysis and mineralization of organic phosphorus (P) were determined in surface water samples collected from inflow and outflow of a submerged aquatic vegetation (SAV)-dominated treatment wetland of the Florida Everglades. Water samples were fractionated into three size fractions (> 0.4 micron, < 0.4 to > 0.05 micron, and < 0.05 micron) with a sequential flow filtration technique. The fractionated water samples were incubated to hydrolyze with alkaline phosphatase (APase) and phosphodiesterase (PDEase), and to mineralize at different redox and pH. Unlike APase, which hydrolyzed < or = 10% of organic P, PDEase hydrolyzed > or = 71% of organic P in unfiltered water from both inflow and outflow waters, suggesting the domination of bioavailable diester P in the water. Phosphodiesterase completely hydrolyzed organic P in the < 0.4- to > 0.05-micron and < 0.05-micron fractions, as compared with < or = 35% in the > 0.4-micron fraction. However, the P mineralization in inflow and outflow waters at different redox and pH showed that P associated with particulate > 0.4 micron had been mineralized the most. Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy showed that surficial sediments from the inflow region contained a high proportion of polynucleotides, nucleoside monophosphates, and previously unreported glycerophosphoethanolamine and phosphoenolpyruvates. However, at the outflow, the relative proportion of polynucleotides and nucleoside monophosphates was reduced substantially. This suggests that the SAV wetland may sequester P via accretion of organic matter.

Influence of flooding on phosphorus mobility in manure-impacted soil

Agricultural lands are often used for constructing stormwater treatment areas (STAs) to abate nutrient loading to adjacent aquatic systems. Flooding agricultural lands to create STAs could stimulate a significant release of phosphorus (P) from soil to the water column. To assess the suitability of agricultural lands, specifically those impacted by animal operations, for the construction of STAs, soils from different components of the New Palm-Newcomer dairies (Nubbin Slough Basin, Okeechobee, Florida, USA) were collected by horizon and their P retention and release capacities estimated. In general, P released from A-horizon soil under flooded (anaerobic) conditions was greater than under drained (aerobic) conditions due to redox effect on iron (Fe) and consequent P releases. However, the P released from Bh-horizon soil was greater under aerobic conditions than under anaerobic conditions, possibly due to excessive aluminum (Al) content in the horizon. Double acid-extractable calcium (Ca), magnesium (Mg), Al, and P explained 87% of the variability in P release under aerobic conditions, and 80% of that under anaerobic conditions. The P release maxima indicated a high solubility of P in A-horizon soil from both active and abandoned dairies (13 and 8% of the total P, respectively), suggesting that these soils could function as potential sources of P to the overlying water column when used in STA construction. Preestablishment of vegetative communities or chemical amendment, however, could ameliorate high P flux from soil to the water column.

Opiates promote T cell apoptosis through JNK and caspase pathway

Opiate addicts are prone to recurrent infections. In the present study we evaluated the molecular mechanism of opiate-induced T cell apoptosis. Both morphine and DAGO ([D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin) enhanced T cell apoptosis. Morphine as well as DAGO activated c-Jun NH2-terminal kinase (JNK) in T cells. Moreover, opiates increased the expression of ATF-2. a specific substrate for JNK and P38 mitogen activated kinases (MAPK). Furthermore, opiates attenuated extracellular signal related kinase (ERK) in T cells. Both morphine and DAGO cleaved pro-caspases 8, 9, and 10 and generated caspases 8, 9 and 10 (active products). Morphine as well as DAGO also cleaved poly-(ADP-ribose) polymerase (PARP) into 116 and 85 kD proteins indicating the activation of caspase-3. These results suggest that opiate-induced T cell apoptosis may be mediated through the JNK cascade and activation of caspases 8 and 3.

Multiple renal arteries do not pose an impediment to the routine use of laparoscopic donor nephrectomy

Since the first description by Ratner and collegues in 1996, laparoscopic live-donor nephrectomy is gaining wide acceptance in an attempt to minimize the donor morbidity, length of hospital stay and length of time to return to work. It is unknown whether multiple renal arteries pose additional problems with laparoscopic donor nephrectomy. In November 1998, our institution initiated laparoscopic donor nephrectomy program. In the ensuing 19 months, we performed 25 living donor renal transplants, 24 of them using laparoscopic donor nephrectomy. The left kidney was procured in all cases. Eight donor candidates (33%) had two or more renal arteries (two arteries in five patients and three patients).

RESULTS

In six cases (25%), findings at surgery differed from the CT angography results (in four cases, CT angiogram reported fewer arteries than were found at surgery and in two cases it reported more). We found no significant differences in both donor outcomes and recipient, based on the presence or absence of multiple renal arteries. Among donor outcomes, we found equivalent results for donor warm ischemia time total donor operating time, and donor length of stay. For recipient outcomes, we found no significant differences between groups for the incidence of acute tubular necrosis (ATN), graft survival and most recent serum creatinine. In one case, we constructed two arteries into a single conduit on the backtable prior to transplantation. However, in most cases with multiple arteries, we implanted the arteries separately into the recipient external iliac artery. Based on this experience, we do not find the presence of multiple renal arteries to be a barrier to the successful use of kidney grafts procured by laparoscopic donor nephrectomy.

Lymphopenia in dialysis patients: a preliminary study indicating a possible role of apoptosis

Lymphopenia is a common finding in dialysis patients. Since infection rate and mortality associated with infection are high in dialysis patients, lymphopenia may be one of the contributing factors. In the present study, we evaluated the mechanism responsible for lymphopenia in these patients. Lymphocytes isolated from dialysis patients showed increased apoptosis (p < 0.001) when compared to lymphocytes isolated from healthy subjects (healthy subjects, 0.5 +/- 0.2% vs. dialysis patients, 8.8 +/- 0.7% apoptotic cells/field). Sera from dialysis patients promoted lymphocyte apoptosis in a time- and dose-dependent manner. These sera also enhanced lymphocyte DNA fragmentation into multiple integers of 180 base pairs in the form of a ladder pattern. Cellulose acetate membranes promoted T cell apoptosis when compared to polysulfone membranes and to control. Cellulose acetate dialysis membranes also appear to promote lymphocyte FasL expression. Similarly, dialysis sera enhanced T cell Fas as well as FasL expression. Neither the cellulose acetate nor polysulfone membranes could induce FasL expression on B cells. Similarly, dialysis sera failed to induce FasL expression on B cells. On the other hand, anti-FasL antibodies attenuated dialysis sera-induced apoptosis in T as well as B cells. Interestingly, dialysis serum showed a 5-fold increase in FasL content when compared with control serum. These results suggest that dialysis-associated factors can induce autocrine death in T cells but the help of activated T cells is required to induce death in B cells.

Isolated cavernous sinus extramedullary relapse of chronic myelogenous leukemia following allogeneic stem cell transplant

Isolated extramedullary relapse of chronic myelogenous leukemia (CML) after allogeneic stem cell transplant is rare. A case is reported of a patient who developed a granulocytic sarcoma of the cavernous sinus 7 months after allogeneic transplant for CML. He presented with neurologic deficits, and a mass lesion was found on imaging. No evidence of hematologic relapse was identified by bone marrow histology or cytogenetics. A premortem diagnosis was not possible, and the patient died 2 months later of an intracerebral hemorrhage after receiving various therapies directed against a presumed infectious etiology. Granulocytic sarcoma should be considered in the differential diagnosis of mass lesions presenting after allogeneic transplant for CML, even if there is no evidence of medullary disease.

Diagnostic laparoscopy: an update

Diagnostic laparoscopy has been in use since the last century. Advances in technology, coupled with increasing evidence of enhanced outcomes following its use, have renewed interest in this modality. Diagnostic laparoscopy guides surgeons in preventing unnecessary laparotomies in settings of acute abdomen, oncologists for accurate staging of malignancies from the esophagus to the colon, and hepatologists in the evaluation of acute as well as chronic liver diseases. Prospective clinical studies are awaited that will allow experimental technological advances, refining the methods of diagnostic laparoscopy, to be translated into more widespread use.

Morphine-induced degradation of the host defense barrier: role of macrophage injury

The effect of morphine on the degradation of the host defense barrier in rats and mice was studied. Mice received either 3 or 11 doses of morphine. Mice receiving 11 doses of morphine showed gram-negative bacteremia and bacterial growth in samples of peritoneal fluid (PF), liver, spleen, kidneys, heart, and lungs; PF and tissue samples from only 1 control mouse showed bacterial growth, and no control mice had bacteremia. Mice receiving 11 doses also had suppressed bone marrow macrophage colony formation. Monocytes and peritoneal macrophages harvested from morphine-treated mice showed greater injury than did those from control mice. Pretreatment of mice with naloxone inhibited morphine-induced macrophage injury and degradation of the host defense barrier. In in vitro studies, morphine attenuated the killing of bacteria phagocytosed by macrophages and also facilitated their escape. This study indicates that morphine-induced monocyte and macrophage injury may be linked to degradation of the host defense barrier.

An analysis of acute changes in interleukin-6 levels after treatment of hepatitis C with consensus interferon

Cytokine production has been implicated in the antiviral response to interferon-alpha (IFN-alpha) in hepatitis C and in the development of IFN-alpha-related side effects. We characterized acute changes in serum cytokine levels following administration of a single dose of consensus IFN (IFN-con1) and during continuous treatment of chronic hepatitis C patients. Serum samples were collected at baseline, at multiple times early after IFN administration, and weekly thereafter. Viral RNA titers were assessed by RT-PCR, and viral kinetics were followed. ELISA assays were used to measure IFN-gamma, tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), IL-4, IL-6, and IL-16. Serum cytokine levels were low at baseline. IL-6 was detected in patients with hepatitis C but not in healthy control subjects by either ELISA or RT-PCR, indicating that low levels of circulating IL-6 were associated with hepatitis C infection. None of the cytokines measured increased significantly after IFN administration except for IL-6. IL-6 levels rose rapidly, peaked at 6-15 h in a dose-dependent manner, and returned to baseline by 48 h in both patients receiving a single dose of IFN and those receiving continuous treatment. This was confirmed by RT-PCR. Pretreatment IL-6 levels were directly correlated with area under the curve (AUC) for IL-6 during the 24 h after IFN dosing (r = 0.611, p = 0.007). Viral titers decreased within 24-48 h after a single dose of IFN-con1. Changes in hepatitis C RNA titers were not significantly associated with pretreatment IL-6 levels or with changes in IL-6 levels. In conclusion, (1) baseline serum cytokine levels, except for IL-6, were low or within the normal range in patients with hepatitis C, (2) IL-6 levels were detected in some patients with hepatitis C before treatment but not in healthy controls, (3) IL-6 levels increased acutely after a single dose of IFN-alpha, and IL-6 induction was related to baseline IL-6 level, and (4) changes in IL-6 levels did not correlate with the early virologic response to IFN.

Glutathione-S-Transferase M1 null genotype in autoimmune hepatitis

Autoimmune hepatitis is associated with genes located in the major histocompatibility complex. The search for genes at other loci that may play a role in disease susceptibility and/or severity is an area of active investigation in autoimmune liver diseases. Genes for glutathione-S-transferases, enzymes that are widely distributed and collectively metabolize carcinogens, pollutants, drugs, and a broad spectrum of harmful, foreign compounds have been associated with liver disease. The objective of this study was to search for a relationship between the glutathione-S-transferase Ml null genotype and autoimmune hepatitis using polymerase chain reaction analysis. The findings indicate that the frequency of the null genotype is not increased in patients with autoimmune hepatitis when compared to control subjects. These results coupled with similar ones in primary biliary cirrhosis do not support a role for this mutation in autoimmune liver disease.

Dilatation of biliary strictures through the afferent limb of a Roux-en-Y choledochojejunostomy in patients with sclerosing cholangitis

Repeated dilatation of biliary strictures in patients with sclerosing cholangitis through a subcutaneously placed afferent limb of a choledochojejunostomy is technically feasible and safe. This study is a prospective 15-year evaluation of 36 patients treated by repeat dilatation through this jejunal limb. There was one operative death and one major complication of dilatation. The 5-year survival of all patients was 74%. If patients with cirrhosis or unproven cholangiocarcinoma at the time of operation are not included, the 5-year survival is 86%. The 15-year survival of all patients was 30%; it was 64% if those with cirrhosis and unproven cholangiocarcinoma at the time of operation are not included. Six patients are presently alive with an average survival of 159 months. The study suggests that a combination of repeated dilatations combined with transplantation is the approach of choice in selected patients.

Airborne radon and its progeny levels in the coal mines of Godavarikhani, Andhra Pradesh, India

In India, out of about 0.7 million miners, nearly 0.5 million persons are directly engaged in coal operations. Radon and its progeny levels have been quantified in the coal-mining environment of Godavarikhani, Andhra Pradesh, India using solid-state nuclear track detectors. Seasonal and mine depth variations in radon levels have been recorded resulting in the identification of locations with a high radon level as areas with no mining activity, active mining operational zones and return air ventilation paths. All these radon levels were below the permissible levels. The average concentrations of radon and its progeny levels were found to be 144 +/- 61 Bq m(-3) and 20 +/- 11 mWL (working level) respectively in the two-incline mine, and these values for the five-incline mine are recorded as 315 +/- 71 Bq m(-3) and 30 +/- 9 mWL respectively.

Temperature effects in treatment wetlands

Several biogeochemical processes that regulate the removal of nutrients in wetlands are affected by temperature, thus influencing the overall treatment efficiency. In this paper, the effects of temperature on carbon, nitrogen, and phosphorus cycling processes in treatment wetlands and their implications to water quality are discussed. Many environmental factors display annual cycles that mediate whole system performance. Water temperature is one of the important cyclic stimuli, but inlet flow rates and concentrations, and several features of the annual biogeochemical cycle, also can contribute to the observed patterns of nutrient and pollutant removal. Atmospheric influences, including rain, evapotranspiration, and water reaeration, also follow seasonal patterns. Processes regulating storages in wetlands are active throughout the year and can act as seasonal reservoirs of nutrients, carbon, and pollutants. Many individual wetland processes, such as microbially mediated reactions, are affected by temperature. Response was much greater to changes at the lower end of the temperature scale (< 15 degrees C) than at the optimal range (20 to 35 degrees C). Processes regulating organic matter decomposition are affected by temperature. Similarly, all nitrogen cycling reactions (mineralization, nitrification, and denitrification) are affected by temperature. The temperature coefficient (theta) varied from 1.05 to 1.37 for carbon and nitrogen cycling processes during isolated conditions. Phosphorus sorption reactions are least affected by temperature, with theta values of 1.03 to 1.12. Physical processes involved in the removal of particulate carbon, nitrogen, and phosphorus are not affected much by temperature. In contrast, observed wetland removals may have different temperature dependence. Design models are oversimplified because of limitations of data for calibration. The result of complex system behavior and the simple model is the need to interpret whole ecosystem data to determine temperature coefficients. Temperature seems to have minimal effect on biochemical oxygen demand (0.900 < theta < 1.015) and phosphorus (0.995 < theta < 1.020) removal, and more significant effect on nitrogen removal (0.988 < theta < 1.16). In colder climates, there may be seasonal slowdown of treatment, which can decrease the overall treatment efficiency of constructed wetlands.

Noncirrhotic portal hypertension

Noncirrhotic portal hypertension represents a heterogeneous group of conditions that have distinct clinical and hemodynamic features that often help distinguish them from cirrhosis. [figure: see text] The sites of portal flow resistance may not be precisely localized to one area of the hepatic lobule and may extend beyond the site where the pathogenetic process began. Even in patients with portal hypertension caused by an increased flow, there may be subsequent development of increased resistance. The prognosis is variable; outcomes are better in patients with presinusoidal portal hypertension. A good understanding of the presentation of the various noncirrhotic conditions that cause portal hypertension will help determine the cause, the site of resistance, and the therapeutic plan. Ascites is not a feature of presinusoidal portal hypertension, whereas it may be the predominant feature in postsinusoidal portal hypertension.

Hepatitis C, cryoglobulinemia, and cutaneous vasculitis associated with unusual and serious manifestations

Hepatitis C viral infection is currently the leading cause of chronic hepatitis and cirrhosis. It also is a major predisposing factor for the development of hepatocellular carcinoma. It is estimated that approximately 1-2% of patients with hepatitis C infection have nonhepatic manifestations that are protean in nature. In this report, we describe six unusual cases of nonhepatic manifestations: abdominal vasculitis in two, peripheral neuropathy in two, and one patient each with central nervous system vasculitis and necrotizing cutaneous vasculitis. All patients had cutaneous vasculitis and cryoglobulinemia. None of our patients had cirrhosis, yet three of the six patients died. Because of the severe manifestations, aggressive therapy was instituted with interferon, immunosuppressive medications, i.v. immunoglobulin, and plasmapheresis. Our report underscores the importance of recognizing nonhepatic manifestations in patients with hepatitis C infection that may be associated with high morbidity and mortality.

Spatio-temporal patterns of soil phosphorus enrichment in Everglades water conservation area 2A

The Florida Everglades have undergone significant ecological change resulting from anthropogenic manipulation of historical regimes of hydrology, nutrient loading, and fire. Water Conservation Area 2A (WCA-2A) in the northern Everglades has been a focal point for the study of ecological effects of nutrient loading, especially phosphorus (P), from the nearby Everglades Agricultural Area (EAA). The overall objective of our study was to evaluate recent (1990 to 1998) changes in the spatial extent and patterns of soil P enrichment in Everglades WCA-2A. Surface soil was sampled to a depth of 10 cm at 62 sites within WCA-2A during 1998 for analysis of total phosphorus (TP) content. Geostatistical methods were used to create an interpolated grid of soil TP values across WCA-2A. Comparison of the results of this study with a similar study performed in 1990 showed that the extent of soil P enrichment in surface soil and sediments increased between 1990 and 1998, as evidenced by increased coverage of highly P-enriched soil near the primary surface inflows and a general increase in the concentration of soil TP in the interior regions of WCA-2A. Approximately 73% (31 777 ha) of the total land area of WCA-2A was considered P-enriched (soil total P > 500 mg kg(-1)) in 1998, compared with 48% of the land area (20,829 ha) in 1990, an average increase of 1,327 ha yr(-1). Study results indicate that the soil P enrichment "front" has advanced further into the relatively unimpacted interior of WCA-2A during the past several years.