Vertebrate seed dispersers maintain the composition of tropical forest seedbanks.

The accumulation of seeds in the soil (the seedbank) can set the template for the early regeneration of habitats following disturbance. Seed dispersal is an important factor determining the pattern of seed rain, which affects the interactions those seeds experience. For this reason, seed dispersal should play an important role in structuring forest seedbanks, yet we know little about how that happens. Using the functional extirpation of frugivorous vertebrates from the island of Guam, together with two nearby islands (Saipan and Rota) that each support relatively intact disperser assemblages, we aimed to identify the role of vertebrate dispersers in structuring forest seedbanks. We sampled the seedbank on Guam where dispersers are absent, and compared this with the seedbank on Saipan and Rota where they are present. Almost twice as many species found in the seedbank on Guam, when compared with Saipan and Rota, had a conspecific adult within 2 m. This indicates a strong role of vertebrate dispersal in determining the identity of seeds in the seedbank. In addition, on Guam, a greater proportion of samples contained no seeds and overall species richness was lower than on Saipan. Differences in seed abundance and richness between Guam and Rota were less clear, as seedbanks on Rota also contained fewer species than Saipan, possibly due to increased post-dispersal seed predation. Our findings suggest that vertebrate seed dispersers can have a strong influence on the species composition of seedbanks. Regardless of post-dispersal processes, without dispersal, seedbanks no longer serve to increase the species pool of recruits during regeneration.

Emerging areas of research reported during the CDC National Conference on Pfiesteria: from biology to public health.

Since its identification in 1996, the marine dinoflagellate Pfiesteria piscicida Steidinger & Burkholder has been the focus of intense scientific inquiry in disciplines ranging from estuarine ecology to epidemiology and from molecular biology to public health. Despite these research efforts, the extent of human exposure and the degree of human illness directly associated with Pfiesteria is still in the process of being defined. Unfortunately, during this same time Pfiesteria has also stimulated media coverage that in some instances jumped ahead of the science to conclude that Pfiesteria presents a widespread threat to human health. Political and economic forces also came into play when the tourism and seafood industries were adversely impacted by rumors of toxin-laden water in estuaries along the east coast of the United States. Amid this climate of evolving science and public concern, Pfiesteria has emerged as a highly controversial public health issue. In October 2000 Centers for Disease Control and Prevention sponsored the National Conference on Pfiesteria: From Biology to Public Health to bring together Pfiesteria researchers from many disparate disciplines. The goal of this meeting was to describe the state of the science and identify directions for future research. In preparation for the conference an expert peer-review panel was commissioned to review the existing literature and identify research gaps; the summary of their review is published in this monograph. During the meeting primary Pfiesteria researchers presented previously unpublished results. The majority of those presentations are included as peer-reviewed articles in this monograph. The discussion portion of the conference focused upon researcher-identified research gaps. This article details the discussion segments of the conference and makes reference to the presentations as it describes emerging areas of Pfiesteria research.

Fish bioassay and toxin induction experiments for research on Pfiesteria piscicida and other toxic dinoflagellates: workshop summary.

In late January 2000, the Centers for Disease Control and Prevention sponsored a workshop to discuss standardizing the laboratory materials and methods used for in vivo fish bioassays and toxin induction experiments. Representatives from six laboratories using these assays to conduct research on Pfiesteria piscicida Steidinger & Burkholder, similar organisms (i.e., members of the toxic Pfiesteria complex) or their toxins were invited to attend. The workshop objectives were a) to discuss the need for uniform quality assurance for fish bioassays and toxin induction, b) to encourage publishing the relevant materials and methods in the literature, c) to foster communication among the laboratories conducting this work, and d) to respond to requests from state health and environmental protection agencies for guidance in interpreting the results from fish bioassays conducted in different laboratories. To facilitate discussion at the workshop, researchers conducting Pfiesteria research completed a detailed questionnaire in advance about fish bioassays and toxin production assays. Workshop participants discussed experimental factors that might influence the reproducibility or interpretation of fish bioassays and toxin-induction experiments. The experimental factors were categorized into physical, chemical, and biological parameters. In addition, participants ranked experimental factors by their relative importance in conducting these assays as a) factors that are critically important and should be maintained within a recommended range, b) factors that are important in conducting the assays but that may be variable among laboratories or within experiments and whose values should be recorded and reported by investigators, and c) factors of unknown importance that should be considered important research questions. This article summarizes results obtained from the questionnaire and workshop discussions.

Environmental public health surveillance: possible estuary-associated syndrome.

Public health surveillance involves the collection, analysis, and dissemination of data for use in public health practice. A surveillance system includes the capacity to collect and analyze data as well as the ability to disseminate the data to public health agencies that can undertake effective prevention and control activities. An emerging issue in environmental public health surveillance involves human exposure to the toxins produced by microorganisms present in oceans and estuaries. One of these organisms is Pfiesteria piscicida Steidinger & Burkholder, a dinoflagellate found in estuaries along the Atlantic and gulf coasts of the United States. There have been reports of both human illness associated with occupational exposures to concentrated laboratory cultures of P. piscicida and massive fill kills associated with the presence of the organism in rivers and estuaries. These reports, and anecdotal reports from people who worked on rivers where the organism has been found, generated concern that environmental exposures to P. piscicida, similar organisms, or perhaps a toxin or toxins produced by the organism(s), could cause adverse human health effects. To begin to evaluate the public health burden associated with P. piscicida, investigators from the National Center for Environmental Health at Centers for Disease Control and Prevention and health agencies from states along the Atlantic coast collaborated to develop a passive surveillance system for collecting, classifying, and tracking public inquiries about the organism. Specifically, the group developed exposure and symptom criteria and developed data collection and reporting capabilities to capture the human health parameters collectively referred to as possible estuary-associated syndrome (PEAS). The surveillance system was implemented in six states (Delaware, Florida, Maryland, North Carolina, South Carolina, Virginia) beginning in June 1998. From 1 June 1998 through 30 June 2001, the six state health agencies participating in the PEAS surveillance system received 3,859 calls: 3,768 callers requested information and 91 callers reported symptoms. Five individuals have been identified as meeting PEAS criteria.

HPLC-MS/MS method for the measurement of seven phytoestrogens in human serum and urine.

The elevated exposure of children to hormonally active dietary phytoestrogens has led to the need for rapid, sensitive, and precise assays for phytoestrogen metabolites in physiological matrices. Here we report the development of a high-performance liquid chromatography (HPLC) MS/MS method for the quantitative detection of seven phytoestrogens in human serum and urine. The method uses enzymatic deconjugation of the phytoestrogen metabolites followed by solid phase extraction (SPE) and reverse-phase HPLC. The phytoestrogens are detected using a Sciex API III heated nebulizer atmospheric pressure chemical ionization (HN-APCI) interface coupled with tandem mass spectrometry. This method allows the detection of the primary dietary phytoestrogens (isoflavones and lignans) in human serum and urine with limits of detection (LODs) in the low parts per billion range. The combination of tandem mass spectrometry and chromatographic separation of the analytes helps ensure the selectivity of the method. Stable isotope-labeled internal standards for all seven analytes improve the precision of the assay, resulting in interday CV values of < 10% for most compounds studied. The accuracy and precision of the method were monitored over time using quality control (QC) samples containing known amounts of phytoestrogens. The majority of phytoestrogens in human sera and urine are present as their glucuronide and sulfate conjugates. Therefore, the thoroughness of deconjugation for each sample was monitored by the addition of a conjugated internal standard and subsequent detection of deconjugated compound. This method proves to be efficacious for measuring baseline urinary phytoestrogen levels in the American population and should prove useful for assessing the modulatory effects of dietary phytoestrogens on endocrine disrupter action in children.

Long-term results of one-stage scrotal patch urethroplasty.

Of 211 patients with urethral strictures undergoing one-stage dartos pedicled island patch urethroplasty between 1970 and 1987, 194 have been followed up from 3 to 20 years. There was 1 post-operative death (from hepatitis). During the period of follow-up, strictures recurred in 14 patients (7%), some of them as late as 15 years after an apparently successful urethroplasty. Calculi forming on hairs required treatment in 6 patients (3%) and it was necessary to revise a redundant skin pouch in 6.

Clinicopathological importance of primary dysplasia of bladder.

A retrospective study of 15 patients with primary dysplasia of bladder urothelium was performed in an attempt to clarify some of the clinical and histopathological features. The lesion occurs predominantly in middle aged men who present with irritative bladder symptoms with or without haematuria and show no evidence of bacteriological urinary tract infection. Appearances at cystoscopy are non-specific. Thirteen patients showed no progression to carcinoma in situ after a long period of follow up, but primary dysplasia cannot be regarded as an entirely innocuous condition as the remaining two patients did develop carcinoma in situ. The grade of dysplasia on presentation bears no relation to the final outcome. Regular cytological analysis of urine seems to be the best means of follow up, and more active treatment does not seem to be justified.

Bronchobiliary fistula due to acute cholecystitis in a suprahepatic gall bladder.

We describe a patient presenting with painless jaundice, anorexia and pruritus. The gall bladder was found to be lying above and behind a hypoplastic right lobe of liver. There was no evidence of cholangitis or biliary obstruction. The patient subsequently developed a bronchobiliary fistula with severe wheeze, cough and bile-stained sputum. Emergency percutaneous drainage of the gall bladder led to immediate cessation of bronchospasm and biloptysis, rendering the patient fit for definitive surgery.

Trial of maximal anal dilatation, cryotherapy and elastic band ligation as alternatives to haemorrhoidectomy in the treatment of large prolapsing haemorroids.

A selected group of 112 patients with prolapsing haemorrhoids which had failed to respond to injections of phenol in oil or which required manual replacement after defecation, were randomly allocated treatment by haemorrhoidectomy, maximal anal dilation, elastic band ligation or cryotherapy. When results were assessed 5 weeks after treatment, haemorrhoidectomy and maximal anal dilatation were equally effective in reducing symptoms, although more physical signs remained after maximal anal dilatation; cryotherapy and elastic band ligation were less effective in both respects. When patients were followed up between 6 months and 5 years haemorrhoidectomy was found to be the most effective method. Patients in the other three groups developed recurrent symptoms requiring haemorrhoidectomy.