Fig-eating by vertebrate frugivores: a global review

The consumption of figs (the fruit of Ficus spp.: Moraceae) by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong. Records of frugivory from over 75 countries are presented for 260 Ficus species (approximately 30% of described species). Explanations are presented for geographical and taxonomic gaps in the otherwise extensive literature. In addition to a small number of reptiles and fishes, 1274 bird and mammal species in 523 genera and 92 families are known to eat figs. In terms of the number of species and genera of fig-eaters and the number of fig species eaten we identify the avian families interacting most with Ficus to be Columbidae, Psittacidae, Pycnonotidae, Bucerotidae, Sturnidae and Lybiidae. Among mammals, the major fig-eating families are Pteropodidae, Cercopithecidae, Sciuridae, Phyllostomidae and Cebidae. We assess the role these and other frugivores play in Ficus seed dispersal and identify fig-specialists. In most, but not all, cases fig specialists provide effective seed dispersal services to the Ficus species on which they feed. The diversity of fig-eaters is explained with respect to fig design and nutrient content, phenology of fig ripening and the diversity of fig presentation. Whilst at a gross level there exists considerable overlap between birds, arboreal mammals and fruit bats with regard to the fig species they consume, closer analysis, based on evidence from across the tropics, suggests that discrete guilds of Ficus species differentially attract subsets of sympatric frugivore communities. This dispersal guild structure is determined by interspecific differences in fig design and presentation. Throughout our examination of the fig-frugivore interaction we consider phylogenetic factors and make comparisons between large-scale biogeographical regions. Our dataset supports previous claims that Ficus is the most important plant genus for tropical frugivores. We explore the concept of figs as keystone resources and suggest criteria for future investigations of their dietary importance. Finally, fully referenced lists of frugivores recorded at each Ficus species and of Ficus species in the diet of each frugivore are presented as online appendices. In situations where ecological information is incomplete or its retrieval is impractical, this valuable resource will assist conservationists in evaluating the role of figs or their frugivores in tropical forest sites.

A 100% 2-year graft survival can be attained in high-risk 15-kg or smaller infant recipients of kidney allografts

BACKGROUND

Infants make up the most high-risk, difficult to care for subgroup undergoing kidney transplantation, with the lowest 1- and 2-year graft survival rates of any other age group. The principal causes of graft loss have been graft thrombosis, primary nonfunction, technical error, and irreversible acute rejection.

HYPOTHESIS

Infants undergoing kidney transplantation can achieve near 100% graft survival at 2 years following surgery, despite their very high-risk status.

DESIGN

Analysis of 45 consecutive kidney transplants performed in patients weighing less than or equal to 15 kg during an 8-year period beginning August 1991. Patients included complex referrals from throughout the United States and all received transplants and were cared for by the same pediatric kidney transplantation team.

RESULTS

Mean weight at transplantation was 11. 2 kg. Renal failure was due to congenital or urologic causes in the majority (53%) of cases. Size-discrepant adult-sized kidney grafts were transplanted in 80% of patients; 64% received live-donor grafts; 78% were receiving dialysis prior to transplantation; and 27% had extremely small bladders (<20 cm(3)) requiring modification of the ureteral implantation. Excluding 1 transplant-unrelated death, graft and patient survival at 2 years was 100%. Eight-year patient and graft survival rates (for our combined live and cadaver donor series) were 89.6% and 84.6%, respectively. This compares favorably with much lower graft survival in low-risk adult recipients. Delayed graft function occurred in only 1 patient (2%). Rate of incidence of rejection was 9.3% within 2 years of transplantation and the overall rejection rate was 15.5%. No graft was lost to vascular thrombosis, primary nonfunction, technical error, or acute rejection. The mean creatinine level was 53.04 micromol/L (0.6 mg/dL) and 61.9 micromol/L (0.7 mg/dL) at 1 and 2 years, respectively, and 88.4 micromol/L (1.0 mg/dL) at 3, 4, and 5 years after transplantation.

CONCLUSION

One hundred percent 2-year and excellent 8-year graft survival rates can be achieved in what has historically been the highest-risk and most difficult to care for patient subgroup undergoing kidney transplantation.

Intravenous ribavirin therapy for adenovirus pneumonia

We report on the effectiveness of intravenous ribavirin for severe adenoviral pneumonia in a 10-month-old male following orthotopic liver transplantation. On day 20 post-transplantation, he developed high fever, marked respiratory compromise, and hypoxemia. The chest radiograph showed bilateral pulmonary infiltrates. Samples of bronchoalveolar lavage fluid grew adenovirus, serotype 1. Marked clinical and radiological improvement was noted after intravenous ribavirin therapy. A prospective clinical trial is needed to determine the efficacy of ribavirin therapy for severe adenovirus disease.

Significance of detecting Epstein-Barr-specific sequences in the peripheral blood of asymptomatic pediatric liver transplant recipients

Pediatric allograft recipients are at increased risk for Epstein-Barr virus (EBV)-associated illnesses. The early identification and diagnosis of EBV-associated disorders is critical because disease progression can often be curtailed by modification of immunosuppression. We have previously shown that detection of EBV-specific sequences in the circulation by polymerase chain reaction (PCR) correlated well with the clinical symptoms of EBV infection. The purpose of the current study is to determine the significance of detecting EBV-specific sequences by PCR in asymptomatic pediatric liver transplant recipients. Peripheral-blood DNA was analyzed for the EBV genes, coding from the nuclear antigen 1 (EBNA-1) and the viral capsid antigen (gp220) by PCR. Samples from asymptomatic pediatric liver transplant recipients were analyzed from the immediate postoperative period and at 2- to 4-month intervals thereafter. We followed up 13 of these asymptomatic recipients who tested positive for EBV compared with 7 asymptomatic recipients who tested negative for EBV during the early posttransplantation period. Follow-up ranged from 1.5 to 4 years posttransplantation. Nine patients (69%) initially positive for EBV and asymptomatic ultimately developed symptoms of EBV infection, including fever, lymphadenopathy, rash, respiratory and gastrointestinal symptoms, and/or hepatitis. Five of these patients (56%) went on to develop posttransplant lymphoproliferative disorder based on histological examination of biopsied tissue and immunohistochemical identification of the EBV antigen/DNA in tissue. This is the first report suggesting that detection of EBV-specific sequences in the absence of symptoms may herald impending EBV-associated disorders. Thus, routine monitoring for circulating EBV sequences in asymptomatic recipients may be useful in the early identification of those at risk for developing EBV-associated disease and its ultimate prevention.

Posttransplant lymphoproliferative disorders and gastrointestinal manifestations of Epstein-Barr virus infection in children following liver transplantation

BACKGROUND

Epstein-Barr virus (EBV) infection is common after liver transplantation in children and is associated with the risk of posttransplant lymphoproliferative disorders (PTLD).

METHODS

This retrospective study examined the frequency of gastrointestinal (GI) symptoms and the risk of PTLD in pediatric liver recipients who developed symptomatic EBV infection. We reviewed 172 children who received orthotopic liver transplants between March 1988 to December 1994. Twenty-two cases were retransplants. The mean age at transplantation was 3.7 years (range, 0.1-17 years). The immunosuppressive regimens consisted of induction therapy with Minnesota antilymphocyte globulin/antithymocyte globulin/OKT3 in most cases and maintenance therapy with prednisone and either cyclosporine or tacrolimus (FK506).

RESULTS

After 1 year of minimum follow-up, 54 of 172 patients had symptomatic EBV infections (confirmed by serology, histology, or whole blood polymerase chain reaction. At the time of infection, 38.5% (21/54) had either diarrhea or GI bleeding or both. PTLD developed in 11 patients (6.4%). The incidence of PTLD was 42.9% (9/21) when GI bleeding or diarrhea was associated with EBV infections, compared with 6.1% (2/33) when EBV infection was not associated with GI symptoms. Seven of 10 (70%) patients with GI bleeding and 2 of 11 (18.2%) with diarrhea developed PTLD. Of seven patients examined by endoscopy for GI bleeding, two had biopsy-proven PTLD of the GI tract, whereas one of two patients examined by endoscopy for diarrhea had biopsy-proven PTLD.

DISCUSSION

In summary, a high incidence of PTLD was found in patients who developed GI bleeding or diarrhea associated with EBV infection after pediatric liver transplantation. In these patients, endoscopy and biopsy may lead to early diagnosis of PTLD.

Current status of living-related liver transplantation

Living-related liver transplantation has come of age. This manuscript addresses the most important facets of the living-related liver transplant procedure including selection of the donor, the recipient operation, immunosuppression and rejection as well as the most common surgical complications. It also describes the results in terms of patient and graft survival, retransplantation and quality of life. Although living-related liver transplantation has not solved the problem of organ shortage, it has provided many children with an opportunity to live and enjoy life.

Aerosol administration of a recombinant adenovirus expressing CFTR to cystic fibrosis patients: a phase I clinical trial

Ad CFTR, a replication-deficient adenovirus expressing the human cystic fibrosis transmembrane conductance regulator (CFTR), was administered by aerosolization in a single escalating dose to three pairs (cohorts) of cystic fibrosis (CF) patients. Buffer only was administered to the nose and lungs 9-14 days before nasal instillation of virus followed the day after by aerosolization of Ad CFTR to the lung. Nasal doses (defined in terms of viral plaque forming units, pfu) were 10(5), 10(7), and 4 x 10(8), whereas aerosolized doses were 10(7), 10(8), 5.4 x 10(8) for each cohort, respectively. No acute toxic effects were observed in the first 4 weeks after virus treatment. Shedding of infectious Ad CFTR was never detected, whereas detection of vector DNA sequences and CFTR expression demonstrated DNA transfer to the nose and airways of patients. No significant deviations in immunological and inflammatory parameters were observed in serum and in bronchoalveolar lavage (BAL). Importantly, for all patients, the serum anti-adenovirus antibody levels did not change significantly from baseline and no antibodies against adenovirus were found in BAL.

Body composition and physical performance in children after renal transplantation

Body composition using standard anthropometric methods and dual-energy X-ray absorptiometry (DEXA) was determined in a cross-sectional study among 26 pediatric renal transplant recipients. At the same time, spiroergometry exam, pulmonary function tests, dynamometry and tremometry exams were performed in all patients. Fat body mass obtained by DEXA correlated inversely with maximal physical load during spiroergometry exam (r2 = 0.51, p = 0.0001). The study demonstrates good tolerance of increased physical load in children after renal transplantation. An inverse relationship was found between fat body mass and physical performance. Exercise training programs for children after renal transplantation are therefore suggested.

Up-regulation of rat adrenomedullin gene expression by endotoxin: relation to nitric oxide synthesis

The effect of bacterial endotoxin (LPS) on adrenomedullin (AM) gene expression was investigated in cultured rat aortic vascular smooth muscle (VSM) cells and in tissues from anesthetized rats. The addition of LPS together with interferon-gamma to VSM cells resulted in a marked increase in the abundance of AM mRNA as well as the appearance of mRNA for the inducible isoform of nitric oxide (NO) synthase (iNOS). Intravenous injection of LPS into rats also increased AM mRNA abundance and induced iNOS mRNA in lung, heart, liver, and kidney. AM significantly enhanced NO synthesis evoked by LPS and interferon-gamma in cultured VSM cells. These data suggest that AM may contribute to circulatory failure during endotoxin shock, in part, by modulating NO synthesis.

Expression of cytokines and immune mediators during chronic liver allograft rejection

To determine the immune processes involved in chronic liver allograft rejection (CR) we examined in situ cytokine production in tissue from 15 patients with both clinical and histopathological diagnoses of CR. Total RNA was isolated from liver samples, reverse-transcribed and analyzed by RT-PCR for the production of proinflammatory cytokines and immunoregulatory mediators. Transcripts for the Th1-like cytokines IL-2 and IFN-gamma were detected in 53.3% and 46.7% of CR grafts, while they were detected in only 16% and 0% of stable grafts, respectively. The cytotoxic T cell mediator granzyme B was expressed in the majority of liver grafts undergoing CR, but was expressed only in a minority of stable grafts (80% vs. 16%, P < 0.05). The T cell product IL-5 was also significantly upregulated in CR as compared with stable livers (80% vs. 16%, P < 0.01). Other Th2 cytokines--IL-4 and IL-10--and macrophage products--IL-1 beta, IL-6, IL-8, TGF-beta, and TNF-alpha--were not substantially upregulated in CR grafts as compared with stable grafts. PDGF-beta transcripts were detected in the majority of the CR grafts, but were not detected in stable liver grafts (73% vs. 0, P < 0.05). By immunohistochemical staining, we observed that CD3+CD4+, and CD3+CD4- T cells were detected in CR grafts along with CD20+ B cells and CD68+ macrophages. There was, however, a predominant infiltration of CD3+CD4+ lymphocytes. Taken together, these data suggest that infiltrating cells produce proinflammatory and immunoregulatory cytokines that have a role in mediating graft damage in CR.

Effects of calcium channel antagonists on the induction of nitric oxide synthase in cultured cells by immunostimulants

We investigated whether calcium channel antagonists would alter the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) alone or in combination with interferon-gamma (IFN gamma) in cultured J774 macrophages, rat vascular smooth muscle cells, rat renal mesangial cells, and rat cardiac myocytes. The induction of NO synthesis was determined by measuring nitrite, the stable end-product. The dihydropyridine calcium channel antagonists, nifedipine, manidipine, nitrendipine, benidipine, barnidipine, perdipine, and nilvadipine all reduced the LPS-induced nitrite production in a dose-dependent manner, each with a differing half-maximal inhibitory concentration, in cultured J774 macrophages. Nifedipine also inhibited nitrite production in vascular smooth muscle cells, mesangial cells, and cardiac myocytes. The half-maximal inhibitory concentrations of nifedipine were ranked as follows: smooth muscle cells < mesangial cells < cardiac myocytes. Diltiazem, at nontoxic concentrations, had no effect on the nitrite formation in the three cell types. Verapamil markedly increased the formation of nitrite in cardiac myocytes in response to LPS and IFN gamma, but not in vascular smooth muscle or mesangial cells. Exposure of cardiac myocytes to LPS and IFN gamma caused the expression of NO synthase mRNA that was significantly increased by verapamil. Thus, certain calcium channel antagonists modulate NO synthesis by altering the induction of NO synthase.

Vesnarinone inhibits induction of nitric oxide synthase in J774 macrophages and rat cardiac myocytes in culture

OBJECTIVE

We investigated whether vesnarinone alters the induction of nitric oxide (NO) synthesis by bacterial lipopolysaccharide (LPS) or in combination with interferon-gamma in cultured J774 macrophages and rat cardiac myocytes.

METHODS

The induction of NO synthesis was determined by measuring the stable end-product nitrite. The cytotoxic effect of vesnarinone was assessed by measuring cell respiration. Any change in mRNA levels for NO synthase (NOS) was determined by RT-PCR.

RESULTS

Stimulation by LPS or in combination with interferon-gamma increased the accumulation of nitrite in the supernatant of J774 macrophages or cardiac myocytes. NOS induction accounted for this accumulation of nitrite, as dexamethasone, NG-methyl-L-arginine, and cycloheximide each reduced the production of nitrite in both types of cells. Vesnarinone produced a significant decline in the cumulative production of nitrite in both types of cells without evidence of cytotoxicity. However, the addition of vesnarinone after induction of NOS did not inhibit nitrite production. Treatment with LPS or in combination with interferon-gamma led to a significant expression of NOS mRNA in both types of cells that was significantly reduced by vesnarinone.

CONCLUSIONS

Vesnarinone inhibited NO synthesis by inhibiting the induction of NOS in J774 macrophages and cardiac myocytes. This drug may exert a beneficial effect in patients with heart failure, in part, by attenuating the production of NO.

Long-term airway considerations after treatment of severe pediatric laryngotracheal stenosis in five children

After initial treatment of severe laryngotracheal stenosis (LTS), we evaluated subsequent airway function. Five children between 2 and 11 years were treated previously for severe LTS by T-tube stenting. One case underwent subsequent laryngotracheal reconstruction. All patients demonstrated dyspnea, the severity of which increased with age and duration of time after completion of stenosis treatment. In the most severe cases, magnetic resonance imaging and endoscopy revealed secondary subglottic stenosis. Ventilatory function tests disclosed obstruction of both extrathoracic and pulmonary origin. These findings raise questions regarding the treatment of the initial stenosing tissue and of the secondary stenoses.

Differential patterns of circulating intercellular adhesion molecule-1 (cICAM-1) and vascular cell adhesion molecule-1 (cVCAM-1) during liver allograft rejection

During allograft rejection, adhesion molecules play an integral role in infiltration, activation, and binding of effector cells to target tissue. Some adhesion molecules, including ICAM-1 and VCAM-1, exist in soluble, circulating forms that retain ligand-binding activity. In the present study the levels of circulating ICAM-1 (cICAM-1) and VCAM-1 (cVCAM-1) were compared in the serum and bile of pediatric liver recipients. The cICAM-1 was significantly elevated in the serum during allograft rejection and infection relative to periods when no rejection was apparent. Biliary cICAM-1, however, was specifically elevated during rejection and not during infection or when no rejection was apparent. The cVCAM-1 levels were elevated in the serum during rejection compared with levels when no rejection was evident. In contrast, cVCAM-1 was not detected in the bile. Serum levels of both cICAM-1 and cVCAM-1 decreased rapidly following successful treatment for rejection, whereas elevated levels persisted, or increased, in ongoing rejection. The differential patterns of the circulating forms of ICAM-1 and cVCAM-1 were consistent with the membrane expression of these molecules during graft rejection. ICAM-1 expression was extensive on bile duct epithelium, endothelium, hepatocytes, and infiltrating leukocytes during rejection, while VCAM-1 was restricted to endothelium. These findings indicate that the release of circulating adhesion molecules is a prominent feature of liver allograft rejection. Measurement of these markers may be useful in distinguishing rejection from infection and in determining the efficacy of treatment for rejection.

Different growth control of the two human thyroid cell lines of adenomatous goiter and papillary carcinoma

To study the growth control of human thyroid cells in different stages of differentiation, we established two human thyroid cell lines of adenomatous goiter and papillary carcinoma. A 59-year-old female patient with adenomatous goiter was operated in September 1991, and a 27-year-old female patient with papillary carcinoma in May 1990. The thyroid cell lines were established by successive passage without cellular or genetic manipulations such as fusing other cell lines or oncogenic viral infection. These cell lines, human adenomatous goiter cells (hAG) and human papillary thyroid carcinoma cells (hPTC), exhibited a flattened polygonal shape and proliferated as a monolayer in cell culture. The doubling time of the hAG cells was 60 h in Ham's F12 medium supplemented with 10% fetal bovine serum, and that of the hPTC cells, 18 h in the same medium. Both cell lines expressed mRNA for TSH receptor and secreted cAMP into the medium during incubation with thyrotropin (TSH) at concentrations as low as 0.01 mU/mL. The effects of activators of protein kinase A (PKA), protein kinase C (PKC), tyrosine kinase (TK), and estradiol (E2) on proliferation of the hAG cells and the hPTC cells were assessed by measuring cellular DNA content in 24-well plates with diaminobenzoic acid. TSH stimulated proliferation of the hAG cells, but it inhibited proliferation of the hPTC cells. Since TSH activates two signaling pathways, the adenyl cyclase-PKA system and phospholipase C-PKC system, we tested effects of dibutylyl cAMP (dBC) and phorbol myristate 13-acetate (PMA), separately. dBC stimulated proliferation of the hAG cells, but it inhibited that of the hPTC cells.(ABSTRACT TRUNCATED AT 250 WORDS)