Management of Meloidogyne incognita with Chemicals and Cultivars in Cotton in a Semi-Arid Environment

Management of Meloidogyne incognita (root-knot nematode) in cotton in the United States was substantially affected by the decision to stop production of aldicarb by its principle manufacturer in 2011. The remaining commercially available tools to manage M. incognita included soil fumigation, nematicide seed treatments, postemergence nematicide application, and cultivars partially resistant to M. incognita. Small plot field studies were conducted on a total of nine sites from 2011-2013 to examine the effects of each of these tools alone or in combinations, on early season galling, late-season nematode density in soil, yield, and value ($/ha = lint value minus chemical costs/ha). The use of a partially resistant cultivar resulted in fewer galls/root system at 35 d after planting in eight of nine tests, lower root-knot nematode density late in the growing season for all test sites, higher lint yield in eight of nine sites, and higher value/ha in six of nine sites. Galls per root were reduced by aldicarb in three of nine sites and by 1,3-dichloropropene (1,3-D) in two of eight sites, relative to the nontreated control (no insecticide or nematicide treatment). Soil fumigation reduced M. incognita density late in the season in three of nine sites. Value/ha was not affected by chemical treatment in four of nine sites, but there was a cultivar × chemical interaction in four of nine sites. When value/ha was affected by chemical treatment, the nontreated control had a similar value to the treatment with the highest value/ha in seven of eight cultivar-site combinations. The next "best" value/ha were associated with seed treatment insecticide (STI) + oxamyl and aldicarb (similar value to the highest value/ha in six of eight cultivar-site combinations). The lowest valued treatment was STI + 1,3-D. In a semi-arid region, where rainfall was low during the spring for all three years, cultivars with partial resistance to M. incognita was the most profitable method of managing root-knot nematode in cotton.

Irrigation Timing Impacts the Efficacy of Foliar-Applied Fungicides Toward Foliar and Soilborne Pathogens of Peanut

Fungicides not reaching target organisms result in decreased disease control. In the southeastern United States, foliar-applied fungicides are routinely used to manage peanut (Arachis hypogaea) diseases. Irrigation is often applied to wash fungicides from treated foliage to obtain maximum control of diseases caused by soilborne pathogens. Administering irrigation before fungicide residues have dried may adversely impact foliar disease control. A microplot study was conducted in 2003, 2004, and 2005 to evaluate the redistribution of azoxystrobin, tebuconazole, and flutolanil plus chlorothalonil following different irrigation timings. Standard fungicide regimes were subjected to 1.3-cm of irrigation 0, 6, 12, 24, 48, or 96 h after application, and a nonirrigated control was included. Microplots not receiving irrigation were covered while irrigation treatments were administered. Irrigation timing was significant for the number of early leaf spot (Cercospora arachidicola) lesions per leaf. Leaf spot was more severe when irrigation was administered immediately following fungicide applications, and was significantly reduced with a 6- and 12-h delay prior to an irrigation event, whereas maximum control was obtained when irrigation was delayed for 24 h or later. To further quantify fungicide residue distribution, Sclerotium rolfsii was used to bioassay foliage and pods. Lesion development on leaflets, which was greater for earlier irrigation timings, did not differ for the 12-h and later timings and was generally similar to the nonirrigated controls. Pod colonization for all fungicides increased according to a quadratic function of irrigation timing, with the least colonization occurring at the 0-h timing. Colonization of pods treated with azoxystrobin was similar for all irrigation timings; whereas, suppression was greatest for tebuconazole at earlier irrigation timings. This study demonstrates that irrigation can be used to redistribute fungicides applied to peanut foliage to improve control of soilborne pathogens but administering irrigation within 24 h may decrease leaf spot control.

First Report of Stemphylium botryosum on Spinach in Texas

During the 2009 to 2010 growing season, symptoms of an unknown leaf spot were observed on spinach (Spinacia oleracea L.) in production fields in southwest Texas. Approximately 500 ha were affected, especially cvs. Rakaia and Viceroy. Disease incidence was 30 and 2% for Rakaia and Viceroy, respectively. Diseased plants exhibited small (1 to 3 mm in diameter), tan, necrotic lesions with a circular to oval shape and were void of any signs of a pathogen. Symptomatic leaves were surface sterilized in 1.5% NaOCl for 1 min, rinsed with sterile water, and air dried. Leaf sections (~1 cm²) were cut and placed on acidified potato dextrose agar (APDA), or APDA supplemented with streptomycin (SAPDA). Fungal mycelia growing from the edges of infected leaf sections were transferred to PDA and incubated at 25°C with a 12-h/12-h light/dark cycle. After 14 days of incubation, dark brown mycelia giving rise to unbranched conidiophores bearing brown, deeply septate, ovoid conidia were observed. Conidia measured 16.8 to 27.3 × 13.1 to 19.6 μm. On the basis of these morphological characteristics, the fungus was identified as Stemphylium botryosum (3). Cultures were transferred to clarified V8 juice agar to obtain inoculum for pathogenicity tests. Eight-week-old plants (n = 20) of spinach cvs. Hybrid 310, Wintergreen, Ashley, and Rakaia were sprayed until runoff with a suspension containing 0.001% Tween 80 and 1 × 10⁴ conidia/ml. Noninoculated plants served as a control treatment. Plants were placed in a growth chamber and incubated in the dark at 25°C and 95% relative humidity. Following 36 h of incubation, plants were transferred to a plastic enclosure and maintained at 23 ± 4°C. After 7 to 10 days, tan, oval-shaped lesions were observed on all inoculated spinach plants. All control plants, with the exception of Rakaia, failed to develop symptoms. Isolates of S. botryosum were recovered on SAPDA from symptomatic leaves, confirming Koch's postulates. Previous reports have shown that S. botryosum can be transmitted from infected seed (1), thus, additional plants of each cultivar (n = 36) were grown in the greenhouse to determine the potential for seedborne contamination. After 8 weeks, leaf spot symptoms identical to those observed on the original plants developed on 75% of the Rakaia plants, while symptom development on the other cultivars was negligible. Isolates of S. botryosum were only recovered from symptomatic Rakaia leaves. Similar field observations were made during the 2001 to 2002 growing season; however, attempts to isolate S. botryosum in that season were unsuccessful. Recent outbreaks of Stemphylium leaf spot have been reported in Arizona (4), California (3), Delaware and Maryland (2), and Washington (1). To our knowledge, this is the first report of S. botryosum on spinach in Texas. While the origin of inoculum causing the disease in Texas is unknown, S. botryosum may have been seedborne (2). The implementation within the past few years of very high density plantings of spinach (1.9 to 3.7 million seeds/ha) may lead to an increase in incidence and severity of this disease in Texas. References: (1) L. J. du Toit and M. L. Derie. Plant Dis. 85:920, 2001. (2) K. L. Everts and D. K. Armentrout. Plant Dis. 85:1209, 2001. (3) S. T. Koike et al. Plant Dis. 85:126, 2001. (4) S. T. Koike et al. Plant Dis. 89:1359, 2005.

First Report of Sclerotinia Stem Rot of Canola Caused by Sclerotinia sclerotiorum in Texas

During the past several years, canola (Brassica napus L.) has been grown experimentally in different areas of Texas to evaluate its potential as a crop, particularly for use as a biofuel source. In early April 2007, symptoms typical of Sclerotinia stem rot were observed in a canola variety trial that was flowering in Wharton County, Texas. Stems had white mycelia growing on the outside, or a bleached appearance, near the soil surface and plants were lodging. Inside bleached stems, there were spherical to cylindrical, black sclerotia that were 3 to 10 mm. Isolations from surface-disinfested stems onto potato dextrose agar (PDA) consistently yielded white, fluffy colonies with sclerotia typical of Sclerotinia sclerotiorum (Lib.) de Bary (1). Sequence analyses were conducted on two replicates of mycelium by extracting fungal DNA with the Qiagen DNeasy Plant Mini Kit (Valencia, CA). PCR amplification was performed using two primer sequences (92-4 AF377919: TCGCCTCAGAAGAATGTGC/AGCGGGTTACAAGGAGATGG; and 119-4 AF377925: GTAACAAGAGACCAAAATTCGG/TGAACGAGCTGTCATTCCC) (2) that have previously been used to characterize S. sclerotiorum (3). The BLAST search revealed that the sequences were 99 and 98% homologous with S. sclerotiorum Accession Nos. AF377919 and AF377925 over 376 and 377 bp of aligned sequence, respectively. Agar segments (1 cm²) from a 5-day-old culture grown on PDA were placed in the leaf axils of 15 2-month-old canola plants ('Wichita') growing in pots. Plants were placed in a humid chamber under fluorescent lights at 16 to 22°C. After 2 days, water soaking and necrosis occurred on petioles and stems adjacent to the inoculum, but not on plants treated with sterile PDA. S. sclerotiorum was consistently reisolated from symptomatic tissue plated on acidified PDA. The inoculations were repeated once with similar results. To our knowledge, this is the first report of Sclerotinia stem rot of canola in Texas. Currently, there is no significant canola production in Texas; however, interest in biofuels could lead to an increase in planted acres. Sclerotinia stem rot of canola could become a significant disease problem in areas of Texas where canola is planted as a winter crop. References: (1) L. M. Kohn. Phytopathology 69:881, 1979. (2) C. Sirjusingh and L. M. Kohn. Mol. Ecol. Notes 1:267, 2001. (3) J. E. Woodward et al. Plant Dis. 92:1468, 2008.

First Report of Sclerotinia sclerotiorum Infecting Peanut in Texas

Peanut (Arachis hypogaea L.) is grown extensively in several counties in West Texas. Sclerotinia blight, caused by the soilborne fungus Sclerotinia minor Jagger, is an increasingly important disease throughout this region. In September of 2007, diseased peanut plants (cv. Tamrun OL02) exhibiting symptoms of Sclerotinia blight (2,4) were collected from a commercial farm in Gaines County during a regional survey. Infected stem sections were surface disinfested in 0.5% sodium hypochlorite for 1 min, air dried, and placed in petri dishes containing water agar. Hyphae were subsequently transferred to petri dishes containing potato dextrose agar (PDA) after 3 days of incubation at room temperature. Pure cultures formed abundant, aerial, white mycelia, which later became darkly pigmented. Black, spherical to elongated sclerotia, 3.8 ± 0.8 mm, formed on the outer edge of petri dishes after 1 week. These characteristics are consistent with S. sclerotiorum (Lib.) de Bary (1,2). Pathogenicity tests were conducted by inoculating stems of greenhouse-grown peanut plants (cvs. Tamrun OL02, n = 4 and Flavorrunner 458, n = 4) with PDA plugs containing S. sclerotiorum. Mounting pins were used to create a shallow wound and affix inoculum plugs to stems. Control plants (n = 4) were inoculated with noncolonized PDA plugs. Plants were placed in a dew chamber at 20°C and 95% relative humidity in a randomized complete block design. The experiment was conducted two times. Symptoms identical to those observed on the original plant specimens were observed after 3 days on all inoculated plants; the controls remained healthy. Darkly pigmented cultures of S. sclerotiorum were consistently reisolated from all symptomatic stem sections. Fungal DNA was extracted from mycelia and sclerotia with a Qiagen DNeasy Plant Mini kit (Valencia, CA) and amplified by PCR using three S. sclerotiorum-specific primer pairs (3). PCR products for three replicates (two from mycelia and one from sclerotia) were sequenced and subjected to a NCBI BLAST search of highly similar sequences (megablast). The BLAST search revealed that our sequences are highly similar only with reported sequences of S. sclerotiorum. Sequences generated from three primer pairs in this study were 99, 95, and 95% homologous to S. sclerotiorum Accessions Nos. AF377925.1, AF377919.1, and AF377904.1 over 373, 376, and 300 bp of aligned sequence, respectively. Results from the pathogenicity tests and molecular study confirm that the S. sclerotiorum isolate obtained in this study is capable of inciting Sclerotinia blight of peanut. While S. minor is the primary causal agent of the disease, recent reports indicate that S. sclerotiorum is becoming more prevalent throughout the peanut-producing regions of the United States (2,4), and must therefore be considered in disease diagnosis. References: (1) L. M. Kohn. Phytopathology 69:881, 1979. (2) S. Sanogo and N. Puppala. Plant Dis. 91:1077, 2007. (3) C. Sirjusingh and L. M. Kohn. Mol. Ecol. Notes 1:267, 2001. (4) J. E. Woodward et al. Plant Dis. 90:111, 2006.

Use of Resistant Cultivars and Reduced Fungicide Programs to Manage Peanut Diseases in Irrigated and Nonirrigated Fields

Field experiments were conducted in 2004 and 2005 to evaluate the response of several peanut cultivars to standard and reduced-input fungicide programs under production systems which differed in the duration of crop rotation, disease history within a field, or in the presence or absence of irrigation. Effects on early leaf spot (caused by Cercospora arachidicola), late leaf spot (caused by Cercosporidium personatum), and southern stem rot (caused by Sclerotium rolfsii), pod yields, and economic returns were assessed. Standard fungicide programs were similar for both sets of experiments and included applications of pyraclostrobin, tebuconazole, azoxystrobin, or chlorothalonil. Reduced-fungicide programs, comprising combinations of the aforementioned fungicides, resulted in two and four applications for the cultivar and irrigation experiment, respectively. Two additional programs (a seven-spray chlorothalonil and a nontreated control) were included in the cultivar experiment. Fungicide programs provided adequate levels of leaf spot suppression, and stem rot incidence was similar among fungicide programs within the two management systems. In the cultivar experiment, returns were significantly lower for the reduced program compared with the full program and seven-spray chlorothalonil program; however, they were significantly higher than the nontreated control. Significant differences in leaf spot, stem rot, and yield were observed among cultivars in both experiments. Overall, leaf spot intensity was lowest for the cvs. Georgia-03L and Georgia-01R and greatest for Georgia Green and Georgia-02C. Georgia-03L, Georgia-02C, and AP-3 consistently had lower incidence of stem rot than the other cultivars. Pod yields for all cultivars were equivalent to or greater than Georgia Green in both experiments; however, the performance of reduced-fungicide programs was inconsistent.

First Report of Sclerotinia minor Infecting Ipomoea hederacea and I. coccinea in Texas

Sclerotinia blight, caused by the soilborne fungus Sclerotinia minor Jagger, is a major disease of peanut (Arachis hypogaea L.) in parts of west Texas. Previous reports have indicated that annual weed species may serve as collateral hosts for S. minor (2). Several Ipomoea spp. are commonly found in peanut fields throughout the region. In September of 2007, Ipomoea hederacea and I. coccinea plants with bleached, shredded stems, and signs of black sclerotia were collected from a field known to be infested with S. minor. Symptomatic stem sections were rinsed in tap water, surface disinfested in 0.5% sodium hypochlorite for 1 min, air dried, and plated on potato dextrose agar (PDA). Pure cultures of S. minor consisting of white, fluffy mycelia and small (<2 mm), black, irregular sclerotia were consistently recovered. Pathogenicity tests were conducted by wound-inoculating healthy I. hederacea and I. coccinea transplants (n = 3) with agar plugs obtained from the edges of actively growing S. minor cultures. Plants were incubated in a dew chamber at 20°C and 95% relative humidity for 5 days. Plants inoculated with sterile PDA plugs served as controls (n = 3). A similar test was conducted using the susceptible peanut cultivar Flavorunner 458. Characteristic symptoms of Sclerotinia blight (3) were observed on all inoculated weed and peanut plants; whereas, the controls remained healthy. Pathogenicity tests were repeated with similar results. Cultures of S. minor were obtained from all symptomatic tissues, fulfilling Koch's postulates. These results indicate that I. hederacea and I. coccinea are additional hosts of S. minor and that sclerotia produced on infected plants can significantly augment soil inoculum. S. minor has been observed to infect I. batatas seedlings in New Jersey (1); however, this to our knowledge is the first report of S. minor infecting Ipomoea spp. in Texas. Therefore, weed management should inevitability be a part of disease management strategies for the control of Sclerotinia blight in peanut. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Handb. No. 165, 1960. (2) J. E. Hollowell et al. Plant Dis. 87:197, 2003. (3) D. M. Porter and H. A. Melouk. Sclerotinia blight. Page 34 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathologicial Society, St. Paul, MN, 1997.

Development of an Inoculation Method for Quantifying Fungicide Residues on Peanut Foliage

A bioassay was developed to evaluate residues of three foliar applied fungicides on peanut leaflets and stems obtained from the upper, middle, and lower canopy. Experiments were conducted to determine the effects of wounding and nutrient source on the development of Sclerotium rolfsii lesions. Results indicated that wounding was not required for infection on either tissue type, and that adequate lesion development was obtained when ¼ strength potato dextrose agar (PDA) was used as a nutrient source. Significant differences in lesion development were observed among canopy layers for leaflets and stems. Tissues collected from the upper canopy were more rapidly colonized by S. rolfsii than tissues from the middle or lower canopy. One-quarter strength PDA was used as a nutrient source to determine an appropriate sample size, and to evaluate the response of S. rolfsii to varying concentrations of azoxystrobin, flutolanil and tebuconazole on non-wounded tissues. Based on differences in the sample mean, standard deviation, and coefficient of variation, a total of 8 to 10 samples are required to obtain a reliable estimate. The application of fungicides significantly reduced the size of S. rolfsii lesions compared to the non-treated controls. Consistent results were obtained from the leaflet and stem assays, and lesion size decreased linearly with increasing log10+1 transformed fungicide concentration. The EC50 values from the leaflet and stem assays were 17.2, 9.5, and 18.1 mg/L, and 18.1, 8.3, and 13.5 mg a.i. /L for azoxystrobin, tebuconazole, and flutolanil, respectively. These results demonstrate an effective method to determine differences in the activity of foliar applied fungicides.

First Report of Sclerotinia Blight Caused by Sclerotinia sclerotiorum on Peanut in Georgia

Sclerotinia blight is one of the most economically important diseases of peanut (Arachis hypogaea L.) in Oklahoma and Virginia. Yield losses of 10% are common in these areas; however, losses may exceed 50% in highly infested fields (1). While Sclerotinia minor is considered the primary causal agent, S. sclerotiorum may also incite the disease. Symptoms typically appear late in the season and are favored by cool temperatures and high relative humidity (RH). Initial symptoms include wilting and yellowing of main or lateral branches. Dense mats of white mycelium develop on diseased areas, and small water-soaked lesions are apparent near the soil line. Lesions become bleached and infected tissues have a shredded appearance. Sclerotia are produced on and inside infected plant parts (2). During October 2004, following a period of heavy rainfall and cool temperatures, peanut plants (cv. Tifrunner) with these symptoms were observed in a field near Surrency, GA. The field had been planted to cotton (Gossypium hirsutum L.) for many years and peanut was strip-tilled into a heavy rye (Secale cereale L.) cover. Disease foci were found throughout the field and final incidence was 20%. Stem sections were surface disinfested in 0.5% sodium hypochlorite for 1 min and plated on potato dextrose agar (PDA). Cultures of S. sclerotiorum (2) were recovered after incubation at 20°C for 2 weeks. Pathogenicity tests were conducted by inoculating wounded peanut mainstems with PDA plugs either with or without the fungus. Inoculation sites were wrapped with moistened cheesecloth, and plants were incubated in a dew chamber at 20°C and 95% RH. There were a total of four replications and the experiment was repeated once. Symptoms consistent with those observed in the field appeared after 3 days and lesion lengths were measured after 5 days. Average lesion lengths were 1.4 and 1.6 cm for cvs. Georgia Green and Tifrunner, respectively Controls remained symptomless. Sections of symptomatic tissue were plated on PDA, and S. sclerotiorum was reisolated from 100% of symptomatic tissue. Although S. sclerotiorum is a common pathogen of various winter crops and weeds found in the southeast, to our knowledge, this is a first report of Sclerotinia blight on peanut in the region. No other occurrences of the disease have been reported since the initial discovery; however, potential losses could be incurred if peanuts are planted in infested fields and harvest is delayed. References: (1) H. A. Melouk and P. A. Backman. Management of soilborne fungal pathogens. Pages 75-85 in: Peanut Health Management. H. A. Melouk and F. M. Shokes, eds. The American Phytopathologicial Society, St. Paul, MN, 1995. (2) D. M. Porter and H. A. Melouk. Sclerotinia blight. Pages 34-36 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathologicial Society, St. Paul, MN, 1997.

First Report of Botrytis Blight of Peanut Caused by Botrytis cinerea in Georgia

Because of the importance of spotted wilt caused by Tomato spotted wilt virus (TSWV), most peanut (Arachis hypogaea L.) breeding programs in the southeastern United States are focusing on developing resistance to TSWV. Many of the cultivars with improved resistance to TSWV are late maturing, requiring 150 days to reach optimum maturity. This factor could greatly impact disease problems at harvest. During November of 2004, an unknown disease was observed on peanut cvs. Georgia 02-C and Hull in a commercial field in Appling County. Symptoms included wilting stems with water-soaked lesions and a dense, gray mold growing on infected tissues. Final disease incidence was less than 5%. For isolation, diseased tissue was surface sterilized by soaking in 0.5% sodium hypochlorite for 1 min, air dried, plated on potato dextrose agar (PDA), and incubated at 20°C. Botrytis cinerea Pers.:Fr., causal agent of Botrytis blight, was isolated from the margins of infected tissue. Mycelia were initially white but became gray after 72 h at which time tall, branched, septate conidiophores formed. Mature, unicellular, ellipsoid, hyaline conidia (8.9 × 10.4 μm) formed in botryose heads (1). Hard, black, irregular-shaped sclerotia formed after 2 weeks. Stems of greenhouse-grown peanut plants (cv. Georgia Green) were inoculated with PDA plugs colonized with either B. cinerea or B. allii Munn. Inoculations were made 3 cm below the last fully expanded leaf on wounded and nonwounded tissue. Noncolonized PDA plugs served as controls (n = 9). Plants were arranged in a dew chamber at 20°C in a randomized complete block design. Lesions and spore masses identical to those observed in the field appeared 3 to 5 days after being inoculated with B. cinerea. The B. allii inoculations caused only superficial lesions. After 5 days, mean lesion lengths for B. cinerea were 59 and 37 mm for wounded and nonwounded inoculations, respectively. B. cinerea was recovered from 100% of the symptomatic tissues. Botrytis blight is considered a late-season disease that occurs in cool, wet weather (3). Symptoms similar to those of Botrytis blight were observed on mature and over-mature peanut in Georgia and have been cited as "unpublished observations" (2); however, to our knowledge, this is the first report of the disease in Georgia. Although Botrytis blight is not considered a major peanut disease, it may become more prevalent at harvest as producers utilize late-maturing cultivars to manage spotted wilt. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Guide of Imperfect Fungi. 4th ed. The American Phytopathological Society, St. Paul, MN, 1998. (2) K. H. Garren and C. Wilson. Peanut Diseases. Pages 262-333 in: The Peanut, the Unpredictable Legume. The National Fertilizer Assoc. Washington D.C. 1951. (3) D. M. Porter. Botrytis blight. Pages 10-11 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathological Society, St. Paul, MN. 1997.

First Demonstration of Koch's Postulates for Lasiodiplodia theobromae Fruit Spot on Eggplant (Solanum melongena)

During October 2004, diseased eggplant fruit from a commercial farm in Colquitt County, Georgia, developed circular, tan, water-soaked lesions. Gray, septate mycelia quickly covered the fruit. Diseased fruit became shriveled, spongy, and mummified. Disease incidence in the field was approximately 1%. Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (synonym Botryodiplodia theobromae Pat.) (2) was isolated from the margins of lesions and cultured on acidified potato dextrose agar. The fungus produced grayish colonies with aerial hyphae and black ostiolate pycnidia massed into stroma. Mature elliptical conidia (25.8 × 15.6 μm) were brown, had a single septation, and longitudinal striations. Isolates obtained from peanut and pecan were included in the pathogenicity tests. Mature fruit cv. Nightshade were surface disinfested for 30 s in 70% ethanol, followed by 60 s in 0.5% sodium hypochlorite, rinsed twice in sterile distilled water, and allowed to dry. Inoculations were made by placing an agar plug containing L. theobromae mycelial side down on the surface of the fruit or wounding with a sterile toothpick containing mycelium of the fungus. Fruit similarly inoculated with agar plugs or sterile toothpicks served as controls. There were a total of three replicates. Fruit were placed in plastic containers lined with moistened paper towels. Containers were placed in a dew chamber and incubated (28°C, relative humidity >95%) for 3 days, and then evaluated. Symptoms identical to those observed on naturally infected fruit developed on inoculated fruit. Controls remained disease free. L. theobromae was reisolated from all symptomatic tissue, satisfying Koch's postulates. Disease damage on wounded fruit was twice that of nonwounded fruit. However, seven of nine inoculations with agar plugs containing L. theobromae resulted in infection. Lesion lengths from wound inoculations were 9.8, 7.3, and 5.2 cm for isolates from peanut, pecan, and eggplant, respectively. Generally, L. theobromae is considered a facultative wound pathogen or a secondary invader (3). However, this study suggests that direct infection can occur. Although fruit spot has been reported previously on eggplant (1), to our knowledge, this is the first report verifying L. theobromae as the causal agent. References: (1) S. A. Alfieri et al. Index of Plant Diseases in Florida. Fla. Dep. Agric. Consum. Serv. Bull. 11, 1984. (2) H. L. Barnett and B. B. Hunter. Illustrated Guide of Imperfect Fungi. 4th ed. The American Phytopathological Society St. Paul, MN, 1998. (3) P. M. Phipps and D. M. Porter. Plant Dis. 82:1205, 1998.

Enhanced allograft survival via simultaneous blockade of transferrin receptor and interleukin-2 receptor

BACKGROUND

Transferrin receptor (TfR) expression follows the induction of interleukin 2 receptor (IL-2R) expression in a sequence that is necessary to initiate cell proliferation in quiescent T lymphocytes. Therefore, we tested the hypothesis that simultaneous blockade of TfR and IL-2R would be more effective in prolonging allograft survival and suppressing T-cell responses to alloantigen than single receptor blockade by modifying T-cell effectors to alloantigen.

METHODS

Neonatal C57BL/6 hearts were transplanted to CBA/J recipients in a heterotopic, nonvascularized cardiac allograft model. Anti-TfR and/or anti-IL-2R or isotype-matched control monoclonal antibodies (mAbs) were administered at 100 microg intravenously on days 0 and 1 of transplantation.

RESULTS

Anti-TfR mAb (25.7+/-0.9 days) significantly (P<0.01) prolonged cardiac allograft survival compared with anti-IL-2R mAb (12.5+/-0.9 days) or the isotype control (15.7+/-1.2 days, P<0.01, Wilcoxon rank-sum). Anti-TfR plus anti-IL-2R mAbs significantly (P<0.01) prolonged cardiac allograft survival to 50.7+/-2.0 days compared with the isotype control or either agent alone. These agents in combination down-regulated the intragraft T helper (Th)-1 cytokines, IL-2, interferon-gamma, and IL-15, while up-regulating the Th2 cytokine, IL-4, and completely abrogating the antigen-presenting cell IL-12p40 mRNA expression.

CONCLUSIONS

Anti-TfR and anti-IL-2R mAbs are potent immunosuppressants. Combined blockade of TfR and IL-2R at the time of antigen presentation seems to be the most effective by shifting the intragraft Th cytokine paradigm.

Differential effects of transferrin receptor blockade on the cellular mechanisms involved in graft rejection

Since transferrin receptor (TfR) appears on activated T cells following the interaction of the antigen-major histocompatibility complex (MHC) with the T cell receptor (TCR) and the appearance of interleukin (IL)-2R, we therefore hypothesize that in vivo blockade of TfR prolongs allograft survival by altering the cellular mechanisms involved in graft rejection. Previous results in our laboratory have demonstrated that anti-TfR monoclonal antibody (mAb) at 100 microg on days 0 and 1 of transplantation significantly prolonged allograft survival to 25.7 +/- 0.9 days in a murine heterotopic, nonvascularized cardiac allograft model. In the current studies, administration of anti-TfR mAb at the time of maximal TfR expression, on days 2 and 3 post-transplantation, failed to prolong allograft survival (13.0 +/- 0.0 days) compared to the isotype controls (10.5 +/- 0.5 and 10.7 +/- 0.4 days) (p < 0.01, Wilcoxon rank sum). A 4-day course of anti-TfR mAb significantly prolonged allograft survival compared to the isotype controls, but was no more effective than a 2-day course of the mAb. Anti-TfR mAb suppressed the mixed lymphocyte response to donor-specific and third-party alloantigen by 78.7% (p < 0.05) and 80.8% (p < 0.05), respectively, while stimulating the CTL response to donor-specific (16.3%, p < 0.05) and third party (49.3%, p < 0.01) alloantigen. Anti-TfR mAb suppressed IL-15 and increased IL-4 intragraft mRNA expression when compared to the isotype controls. Examination of cell surface receptors important during T cell activation revealed alterations in expression following anti-TfR mAb treatment. Anti-TfR mAb is an effective immunosuppressant prolonging allograft survival by altering cell-mediated immune responses and the intragraft cytokine micro-environment.

T-cell alterations in cardiac allograft recipients after B7 (CD80 and CD86) blockade

BACKGROUND

T-cell activation requires engagement of the T cell receptor with the antigen-MHC and simultaneous ligation of the coreceptor CD28. CD28 binds both the CD80 (B7-1) and CD86 (B7-2) ligands on antigen-presenting cells. The functional role of these costimulatory pathways in transplantation is not completely understood. We tested the hypothesis that in vivo blockade of the CD28 pathway via the anti-CD80 and anti-CD86 monoclonal antibodies (mAbs) would prolong allograft survival.

METHODS

Neonatal C57BL/6J (H2b) hearts were transplanted to CBA/J (H2k) recipients in a heterotopic nonvascularized model, with anti-CD80 and/or anti-CD86 mAbs being administered intravenously at the time of allografting (day 0) and on the following day (day 1).

RESULTS

Anti-CD80 mAb (29.8+/-1.5 days) and anti-CD86 mAb (30.8+/-0.5 days) alone significantly prolonged allograft survival compared with the isotype control (10.7+/-0.4 days, P < 0.01, Wilcoxon rank sum). The concurrent (days 0 and 1) and sequential administration of anti-CD86 mAb on days 0 and 1 plus anti-CD80 mAb on days 2 and 3 prolonged allograft survival to >80 days. Simultaneous administration of anti-CD80 and anti-CD86 mAbs significantly suppressed donor-specific cytotoxic T lymphocyte responses to alloantigen. Anti-CD86 mAb suppressed intragraft interleukin (IL)-4, IL-10, IL-12 p40, and IL-15 mRNA expression.

CONCLUSIONS

Anti-CD80 and/or anti-CD86 mAbs are potent immunosuppressants in prolonging allograft survival. Combined blockade of the B7 (CD80 and CD86) ligands seems to be the most effective in prolonging allograft survival and suppressing donor-specific allogeneic cytotoxic T lymphocyte responses. In vivo blockade of CD86, in comparison to CD80, had the greatest immunosuppressive effect on day 7 intragraft cytokines, suggesting its role on early allogeneic immune responses.

Transferrin receptor in T cell activation and transplantation

Transferrin receptor (TfR) expression is up-regulated during T cell activation after the interaction of the T cell receptor with the antigen-major histocompatibility complex and the expression of interleukin-2 (IL-2) receptor. We hypothesize that anti-TfR monoclonal antibody (mAb) will prolong allograft survival by altering T cell responses. In a murine heterotopic nonvascularized cardiac allograft model, CBA/J (H-2k) recipients were transplanted with neonatal C57BL/6 (H-2b) donor hearts. Anti-TfR or isotype-matched control mAbs (100 microg) were administered at the time of transplantation and on the following day. Splenocytes from naive CBA/J mice were stimulated in vitro with C57BL/6 alloantigen. Anti-TfR mAb was administered at 5 microg/mL during the initiation of culture. Cytotoxic T lymphocyte (CTL) and mixed lymphocyte responses (MLR) were performed to assess T cell function. After 24 h in culture, cells were harvested, RNA isolated, and semi-quantitative reverse transcriptase-polymerase chain reaction performed. Anti-TfR mAb prolonged allograft survival to 25.7 +/- 0.9 days compared to the isotype control (10.7 +/- 0.4 days, P < 0.01, Wilcoxon rank sum). Anti-TfR mAb completely abrogated the CTL response and suppressed the MLR by 70-86% compared to the isotype controls. Anti-TfR mAb suppressed IL-2, interferon-gamma (IFN-gamma), IL-10, and IL-12 p40 mRNA expression, but had no effect on IL-4, IL-12 p35, and IL-15 mRNA expression. In conclusion, anti-TfR mAb prolongs allograft survival, suppresses T cell function, and alters IL-2, IL-10, IL-12 p40, and IFN-gamma mRNA expression. These data suggest that the down-regulation in IL-12 mRNA by anti-TfR mAb may prevent the development of T helper cells, thereby promoting graft survival and altering cell-mediated immune responses. The partial effect by anti-TfR mAb on cytokine mRNA expression may be due to other contributing factors such as costimulation.

Anti-transferrin receptor monoclonal antibody: a novel immunosuppressant

BACKGROUND

Transferrin receptor is a widely distributed cell surface receptor present on most proliferating and highly specialized quiescent cells. Expression of transferrin receptor on the surface of immune cells is up-regulated during T-cell activation after the interaction of the antigen-MHC with the T cell receptor. The role of transferrin receptor in T-cell activation has not been well-established. Since transferrin receptor is physically associated with the CD3 zeta-chain, blockade of transferrin receptor has the potential to interfere with the T-cell signals important in transplant rejection.

METHODS

Anti-transferrin receptor monoclonal antibody (mAb) was administered in vivo and in vitro to determine whether this agent was effective in prolonging allograft survival and altering cell-mediated immunity.

RESULTS

Using donor C57BL/6J (H2b) hearts transplanted to CBA/J (H2k) recipients, anti-transferrin receptor mAb at the time of transplantation prolonged cardiac allograft mean survival time to 25.7+/-0.9 days compared with untreated (13.3+/-0.6 days, P < 0.05) or isotype-matched (10.7+/-0.4 days, P < 0.05) controls. Anti-transferrin receptor mAb administered in vivo failed to suppress the subsequent allogeneic responses. However, when added to culture, anti-transferrin receptor mAb suppressed the allogeneic cytotoxic T lymphocyte response by 79-100% but not the mixed lymphocyte response.

CONCLUSIONS

These studies are the first to suggest that transferrin receptor is a potential therapeutic target for clinical transplantation. Future studies will determine the most efficacious dose and time for maximal immunosuppression and the mechanisms responsible for the immunosuppression exhibited by antitransferrin receptor mAb.

Blockade of multiple costimulatory receptors induces hyporesponsiveness: inhibition of CD2 plus CD28 pathways

T-lymphocyte activation requires engagement of the T cell receptor with antigen-major histocompatibility complex, and simultaneous ligation of costimulatory pathways via the lymphocyte receptors CD2 and CD28/ CTLA4. Anti-CD2 monoclonal antibody (mAb) blocks the interaction of the antigen-presenting cell receptor CD48 with its ligand CD2, whereas CTLA4Ig binds with high affinity to the antigen-presenting cell ligands B7-1 and B7-2, blocking their interaction with CD28/CTLA4. We tested the immunosuppressive effects of simultaneously blocking both costimulatory pathways. Using donor C57BL/6J (H2b) hearts transplanted to CBA/J (H2k) recipients, anti-CD2 mAb plus CTLA4Ig administered at the time of transplantation prolonged cardiac allograft mean survival time to >120 days compared with untreated controls (12.2+/-0.5 days, P<0.01), anti-CD2 mAb alone (24.8+/-1.0 days, P<0.01), or CTLA4Ig alone (55.0+/-2.0 days, P<0.01). Retransplantation of these recipients with donor-specific and third-party grafts demonstrated that hyporesponsiveness and tolerance were achieved. In vitro stimulation of lymphocytes from tolerant recipients with donor-specific alloantigen resulted in normal cytotoxic T lymphocyte and mixed lymphocyte reaction responses, showing that clonal deletion or anergy did not occur, but that graft adaptation or suppression likely helped to maintain long-term graft survival. In vitro combinations of anti-CD2 mAb and CTLA4Ig suppressed the generation of allogeneic cytotoxic T lymphocytes (58%) and the mixed lymphocyte reaction (36%); CTLA4Ig was more effective in this regard and the two agents were not synergistic. Anti-CD2 mAb and CTLA4Ig suppressed mitogen-driven proliferation in differential fashions, suggesting that they affected independent signaling pathways. Anti-CD2 mAb and CTLA4Ig also inhibited interleukin (IL)-2, IL-4, and IL-2 receptor (CD25). These data indicate that anti-CD2 mAb plus CTLA4Ig induces hyporesponsiveness and tolerance. The mechanism is likely related to the initial disruption of independent pathways of T-lymphocyte activation leading to antigen-specific long-term graft survival.

Retrovirus-mediated transfer of viral IL-10 gene prolongs murine cardiac allograft survival

A murine heterotopic, nonvascularized cardiac allograft model was used to examine the effects of the immunosuppressive cytokine, viral IL-10 (vIL-10), delivered by gene transfer on graft rejection. Retroviral-mediated gene transfer and expression of vIL-10 significantly prolonged allograft survival, without conventional systemic immunosuppression, from 12.1 +/- 0.8 days to 39.4 +/- 2.5 days (p < 0.0001). The effect was specific, dose dependent, and restricted to the site of transplantation. PCR analysis demonstrated specific expression of the transferred gene within the allograft. Analysis of the cellular infiltrate in the allografts showed a reduction in T cells and alloantigen-specific cytotoxic T cells and IL-2 producing helper T cells. Thus, the transient local expression of a gene encoding an immunosuppressive protein within a graft can generate local immunosuppression, making gene therapy a viable approach for facilitating transplantation.

Retrovirus-mediated transfer of viral IL-10 gene prolongs murine cardiac allograft survival

A murine heterotopic, nonvascularized cardiac allograft model was used to examine the effects of the immunosuppressive cytokine, viral IL-10 (vIL-10), delivered by gene transfer on graft rejection. Retroviral-mediated gene transfer and expression of vIL-10 significantly prolonged allograft survival, without conventional systemic immunosuppression, from 12.1 +/- 0.8 days to 39.4 +/- 2.5 days (p &lt; 0.0001). The effect was specific, dose dependent, and restricted to the site of transplantation. PCR analysis demonstrated specific expression of the transferred gene within the allograft. Analysis of the cellular infiltrate in the allografts showed a reduction in T cells and alloantigen-specific cytotoxic T cells and IL-2 producing helper T cells. Thus, the transient local expression of a gene encoding an immunosuppressive protein within a graft can generate local immunosuppression, making gene therapy a viable approach for facilitating transplantation.

Multiple vectors effectively achieve gene transfer in a murine cardiac transplantation model. Immunosuppression with TGF-beta 1 or vIL-10

The application of gene transfer techniques to organ transplantation offers the potential for modulation of immunity directly within an allograft without systemic side effects. Expression vectors and promoter elements are important determinants of gene transfer and expression. In this study, various vectors (naked plasmid DNA, retroviral vector, herpes simplex viral vector, and adenoviral vector) with various promoters (RSV-LTR, SV40, MuLV-LTR, HCMVie1) were directly compared to demonstrate the successful gene transfer and expression of beta-galactosidase in murine myoblasts in vitro and within murine heterotopic, nonvascularized cardiac isografts or allografts in vivo. Expression of transferred genes was not toxic to cells and strength of expression varied according to the type of vector. Plasmid DNA was expressed in myocytes, retroviral vector was expressed in the graft infiltrating cells, and herpes simplex and adenoviral vectors were expressed in both myocytes and graft-infiltrating cells. Preliminary studies evaluated the ability of these vectors to deliver immunologically important signals. Allografts injected with pSVTGF-beta 1, a plasmid-encoding transforming growth factor beta 1 (TGF-beta 1) under the control of the SV40 promoter, showed significant prolongation of graft survival of 26.3 +/- 2.5 days compared with 12.6 +/- 1.1 days for untreated allografts, and 12.5 +/- 1.5 days for the allografts injected with control plasmid (P < 0.05). Allografts injected with MFG-vIL-10, a retroviral vector encoding viral interleukin-10 under the control of the MuLV-LTR, showed prolongation of graft survival of 36.7 +/- 1.3 days versus 12.6 +/- 1.1 days for the untreated allograft, and 13.5 +/- 2.0 days for the allografts injected with control retroviral vector (P < 0.001). Both vectors were transcriptionally active in vivo and did not appear to have toxic effects. Gene therapy for transplantation can induce transient expression of immunologically relevant molecules within allografts that impede immune activation while avoiding the systemic toxicity of conventional immunosuppression.

Gene transfer for transplantation. Prolongation of allograft survival with transforming growth factor-beta 1

OBJECTIVE

The authors tested the ability of plasmid gene transfer to express transforming growth factor-beta 1 (TGF-beta 1), prolong allograft survival, and evaluate promoter effects on gene expression.

SUMMARY BACKGROUND DATA

Delivery of immunosuppressants directly to allografts using gene transfer and gene therapy approaches may inhibit immune activation while avoiding the systemic toxicity of conventional immunosuppression. Candidate genes include soluble cytokines, which could be expressed at low levels throughout the graft while inducing a local immunosuppressive effect. Transforming growth factor-beta 1 is a soluble cytokine that has pleiotropic immunosuppressive effects.

METHODS

Cardiac grafts from syngeneic (CBA/J, H-2k) or allogenic (C57BL/6, H-2b) donors were placed into CBA/J recipients. Purified plasmid DNA-encoding murine TGF-beta 1 or beta-galactosidase (Lac Z) under the control of RSV, SV40, MMTV, or pancreatic elastase promoters was injected into grafts at surgery. The Lac Z expression was determined by histologic examination and TGF-beta 1 expression by graft survival. Cytotoxic T lymphocyte and flow cytometric analyses were performed to evaluate the immunosuppressive effects of TGF-beta 1 in vitro.

RESULTS

Plasmid DNA-encoding TGF-beta 1 prolonged survival from 12.6 +/- 1.1 days to 26.3 +/- 2.5 days (p < 0.02, Student's t test). The SV40 promoter was superior to the MMTV promoter in its ability to prolong survival. The effects of the plasmids were specific because Lac Z, antisense TGF-beta 1 inserts, or pancreatic elastase promoter did not prolong allograft survival. Histologic examination demonstrated Lac Z expression at least 14 days post-transplant in myocardial cells. Both RSV and SV40 promoters were effective in this respect, while a control null promoter was not. Toxicity testing showed that gene transfer of TGF-beta 1 did not alter survival or histology of syngeneic grafts. In addition, plasmids and purified TGF-beta 1 protein were not toxic to myoblasts in vitro. Recombinant TGF-beta 1 inhibited cytotoxic T lymphocyte generation and altered T cell surface receptor expression and subset expansion in vitro.

CONCLUSION

Gene transfer/therapy with plasmid DNA encoding TGF-beta 1 in vivo achieves immunologic effects that prolong allograft survival. Multiple promoters effectively induce plasmid expression, which is achieved in cardiac myocytes for at least 2 weeks without toxicity or adverse systemic effects. Transforming growth factor-beta 1 inhibits immune responses by different mechanisms, revealed by in vitro analysis of T cell cytolytic function, subset distribution, and receptor display.

Anti-CD2 monoclonal antibodies synergize with FK506 but not with cyclosporine or rapamycin to induce tolerance

CsA, FK506, and rapamycin prolong allograft survival; however, each has significant associated side effects at therapeutic doses. Anti-CD2 mAbs also prolong survival but without toxicity. We tested whether alpha CD2 mAbs in combination with subtherapeutic immunosuppression could prolong allograft survival in a synergistic fashion. C57BL/6 (H-2b) mouse hearts were transplanted to CBA (H-2k) mice in a heterotopic, non-vascularized cardiac allograft model. Recipients received immunosuppressants intraperitoneally for 14 days and/or alpha CD2 mAb intravenously for 2 days starting at the time of grafting. Survival was determined by electrocardiogram monitoring. Anti-CD2 alone prolonged survival to 22.4 +/- 1.0 days versus 13.4 +/- 0.5 days for untreated controls (P < 0.05), while low dose FK506 minimally prolonged survival to 16.7 +/- 0.7 days (P < 0.057). However, FK506 plus alpha CD2 resulted in synergistic prolongation of graft survival to 28.0 +/- 2.1 days. Several doses of CsA and rapamycin in combination with alpha CD2 did not prolong survival over alpha CD2 administered alone. A 60-day course of low dose FK506 plus alpha CD2 resulted in indefinite graft survival (> 165 days). These animals were tolerant since they accepted a second donor-specific graft. CTL and MLR activity in long-term recipients were normal to both donor-specific and third party alloantigen. The combination of alpha CD2 with low dose FK506 is synergistic in prolonging cardiac allograft survival, while combinations with CsA and rapamycin are not. Continuous administration of low dose FK506 plus alpha CD2 results in a state of tolerance. This suggests that FK506 acts at a different locus in allograft immunity compared with the other immunosuppressants and this may be related to the alternative CD2 T cell activation pathway.

Intestinal malabsorption of 45calcium in young Gy mice, a second model for X-linked hypophosphatemia

X-linked hypophosphatemia, a common metabolic bone disease in humans and mice (the Hyp and Gy mutations), is characterized by decreased plasma phosphate, decreased renal tubular reabsorption of phosphate, rickets, and osteomalacia. The question of whether intestinal malabsorption of calcium contributes to the bone disease is controversial. Intestinal absorption of 45Ca was studied in three different mouse colonies: Gy on B6C3H background, Hyp on B6C3H background, and Hyp on C57BL/6J background, all at 4 weeks of age. The duodenum was isolated by sutures, and 45Ca in a 150 mM NaCl and 2 mM CaCl2 solution at pH 7.2 was injected into the lumen. Absorption was measured by the amount of 45Ca remaining in the lumen and by the plasma isotope level. The Gy and Hyp mice of both sexes significantly malabsorbed 45Ca at 4 weeks of age compared to normal littermates. Following the 4 week study, intestinal absorption was measured at 2, 7-8, and 12 weeks of age in normal and Gy mice on the B6C3H background. At 2 and 7-8 weeks of age, the Gy males significantly malabsorbed 45Ca compared to their normal littermates. Serum 1,25-dihydroxyvitamin D was not significantly altered in Gy males at 4 weeks of age. This suggests the possibility of resistance of the intestine to stimulation. Malabsorption of calcium in young Gy and Hyp mice may exacerbate the low mineralization in their rachitic bone disease.

Combination anti-CD2 and anti-CD3 monoclonal antibodies induce tolerance while altering interleukin-2, interleukin-4, tumor necrosis factor, and transforming growth factor-beta production

OBJECTIVE

These studies were designed to elucidate the mechanism by which signals delivered by anti-CD2 monoclonal antibody (MoAb) interfere with activational signals delivered by anti-CD3 MoAb and induce long-term graft survival and tolerance.

SUMMARY BACKGROUND DATA

Anti-CD2 or anti-CD3 MoAb can prolong allograft survival when administered alone. In combination, they synergistically prolong survival while reducing anti-CD3-associated cytokine toxicity. It was postulated that the mechanism of synergism and reduced cytokine toxicity was related to anti-CD2-induced alterations in anti-CD3-induced T-cell activation.

METHODS

C57BL/6 (H-2b) mouse hearts were transplanted to CBA (H-2k) mice. The recipients received anti-CD2 and/or anti-CD3 MoAb intravenously only at the time of initial allografting. Serum from treated animals and culture supernatants from lymphocytes stimulated in vitro with anti-CD3 were examined for interleukin (IL)-2, -4, -6, and -10, tumor necrosis factor (TNF), and transforming growth factor-beta (TGF beta). RNA was isolated from lymphocytes from treated animals and examined for receptor and cytokine gene expression by northern hybridization or reverse transcribed and amplified by the polymerase chain reaction (PCR).

RESULTS

Anti-CD2 and anti-CD3 MoAbs alone prolonged graft survival (22.0 +/- 0.5 days and 28.0 +/- 0.5 days, respectively; p < 0.02 and p < 0.01 vs. control, by Wilcoxon signed-rank test). Combined anti-CD2/anti-CD3 MoAbs synergistically prolonged survival indefinitely (> 150 days, p < 0.01) while decreasing cytokine toxicity. Second donor-specific allografts also showed long-term survival. The peak serum TNF concentration (2100 units/mL) was reduced 78% by anti-CD2 treatment (455 units/mL). Anti-CD2 inhibited anti-CD3-stimulated proliferation and in vitro production of IL-2 and IL-4, with no alteration of IL-6, IL-10, or TNF. Conversely, there was an increase in the immunosuppressive cytokine TGF beta. PCR analysis showed that anti-CD2 reduced anti-CD3-stimulated IL-2 messenger RNA expression, and by northern analysis, anti-CD2 inhibited anti-CD3-stimulated increases in messenger RNA for the CD2 and CD3 receptors themselves.

CONCLUSIONS

The combination of anti-CD2 and anti-CD3 MoAbs induced a state of tolerance while decreasing anti-CD3-associated cytokine toxicity. The mechanism was related to anti-CD2-generated alterations in T-cell activation and gene expression.

Treatment failure in endometrial carcinoma

Endometrial carcinoma has been regarded as one of the more curable gynecologic malignancies. Clinical stage, grade, and depth of myometrial invasion are well-established prognostic variables. We examined the clinical course of 520 patients with endometrial carcinoma treated at Walter Reed Army Medical Center and the Naval Hospital, Bethesda, Maryland, between January 1, 1960 and December 31, 1982. Life table 5-year survivals for stages Ia, Ib, II, III, and IV were 89, 92, 77, 27, and 0%, respectively. Compared with patients with grade 1 endometrial adenocarcinomas, significant decreases in survival were noted for patients with grade 2 or 3 endometrial, papillary endometrioid, serous papillary, and clear-cell tumors. There were six treatment-related deaths (1.2%). Thirty-eight patients (7.3%) developed recurrent disease, with a median time to recurrence of 15 months and a median survival of 21 months. Two of 11 patients with pelvic recurrence were salvaged by radiotherapy, whereas none of 27 patients with distant failure survived. Sixteen advanced-stage patients (3.1%) with persistent disease had a median survival of 4.5 months. Patients with advanced disease or unfavorable histologic subtypes responded poorly to conventional therapy. Current salvage treatments are largely ineffective. Combined-modality therapy and systemic adjuvant therapy should be prospectively evaluated in high-risk patient subgroups.

Intraoperative evaluation of depth of myometrial invasion in stage I endometrial adenocarcinoma

In patients with stage I endometrial adenocarcinoma, the incidence of pelvic and para-aortic lymph node metastasis is related to the grade of the tumor and the depth of myometrial invasion. Although the grade of the tumor may be predicted preoperatively by endometrial sampling, the depth of myometrial invasion cannot be determined until after the uterus has been removed. Although complications have been attributed to lymph node sampling, failure to perform the procedure in patients at risk for nodal metastasis may result in underdiagnosis of extrauterine disease, leading to inadequate therapy. Gross visual examination of the cut surface of the tumor at the time of hysterectomy accurately determined the depth of myometrial invasion in 135 of 148 prospectively studied patients (91%) (P less than .001). The sensitivity of the test was 0.71, the specificity was 0.96, and the positive predictive value was 0.80. Intraoperative assessment of the depth of myometrial invasion is a simple, inexpensive, and useful technique for selecting those patients with stage I endometrial adenocarcinoma who might benefit from selective para-aortic lymphadenectomy.

Widespread lymph node metastases in a patient with microinvasive cervical carcinoma

Lymph node metastasis is uncommon in patients with microinvasive squamous cell carcinoma of the cervix and is particularly unusual in tumors with early stromal invasion. We describe a patient with maximum stromal invasion of 0.8 mm who had extensive pelvic and para-aortic nodal metastases discovered at laparotomy. Despite combined modality therapy, she died with progressive disease. New clinical staging definitions for Stage IA cervical carcinoma incorporate measurement of both depth of invasion and lateral tumor spread and have resolved many of the descriptive controversies surrounding this entity. Our case illustrates that any degree of stromal invasion carries some risk of nodal metastasis. The management of patients with microinvasive carcinoma should be individualized. An abdominal approach should be considered for patients being treated by extrafascial hysterectomy to allow assessment of the regional lymph nodes. Whether more aggressive therapy will influence the outcome for the rare patient with lymph node metastasis is unknown.

Endodermal sinus tumor of the infant vagina treated exclusively by chemotherapy

A 5-month-old Hispanic female, diagnosed as having endodermal sinus tumor of the vagina, was treated with combination chemotherapy in an attempt to preserve pelvic function. An incisional biopsy was performed before starting chemotherapy. After completion of chemotherapy, no residual disease was found at exploratory laparotomy. The patient received no further therapy and is disease-free 45 months later. This case represents successful treatment of a vaginal endodermal sinus tumor without any operative excision.

Diagnosis of recurrent gynecologic malignancy with fine-needle aspiration cytology

Between 1980-1985, 177 fine-needle aspirations were performed on 139 patients suspected of having recurrent gynecologic malignancy. Suspected sites of recurrence included a pelvic mass (122), peripheral lymph node (39), and a variety of other locations (16). There were 69 positives, 79 negatives, eight suspicious specimens, and 21 specimens inadequate for interpretation. Excluding suspicious or inadequate specimens, the results of the remaining 148 evaluable aspirations were confirmed by histopathologic correlation (35) or subsequent clinical course (113). Because there were no false positives, the specificity of the technique was 100%. The sensitivity was 68%, with an associated false-negative rate of 32%. The predictive value of a positive was 100%; that of a negative was 57%. An analysis of the false-negative results failed to show a correlation with cell type, lesion location, previous radiotherapy, or previous chemotherapy. The complication rate was less than 1%. These data support the conclusion that fine-needle aspiration cytology is a safe, highly specific method for diagnosing recurrent gynecologic malignancy. However, in patients with negative fine-needle aspiration cytology and suspected recurrent disease, it would appear that further evaluation is indicated.

Retroperitoneal teratoma presenting as an abdominal-pelvic mass

Nonovarian teratomas are relatively common neoplasms in children, but are rarely seen in adults. A case of a large retroperitoneal teratoma in a 42-year-old woman is presented. The 21.5-kg tumor originated in the retroperitoneal space inferior to the origin of the superior mesenteric artery, and displaced the contents of the entire abdominal cavity. The duodenum, pancreas, and transverse colon mesentery were incorporated into the tumor's pseudocapsule. Evaluation and operative management are described. Diagnosis and pathogenesis of nonovarian teratomas are reviewed.

Histology of proximal tubal occlusion

From 1979 to 1985, 18 patients who were found to have proximal tubal obstruction by hysterosalpingography and laparoscopic chromopertubation underwent resection of the obstructed tubal segment and reimplantation or microanastomosis. Resected tubal segments were studied histologically, and in 11 of the 18 cases no tubal occlusion could be demonstrated. A variety of histologic abnormalities were noted, however, including six cases in which the tubal lumen contained an amorphous material of unknown etiology, often appearing to form a cast of the tube. Such "plugs," which the authors believe to be previously unreported, have no clearly established clinical significance at present. However, if they cause tubal occlusion, this would explain several previously published findings, and would also have implications for therapy.

Lipid composition and lipid metabolism of Spiroplasma citri

In a horse serum-based medium containing a full complement of fatty acids, cells of Spiroplasma citri were seen to preferentially incorporate palmitic acid. In the same medium, which had a steryl ester-to-sterol ratio of 3.64, a steryl ester-to-sterol ratio of 0.23 was seen in the cells, cholesterol being preferentially incorporated over cholesteryl ester. Like most other mycoplasmas, S. citri was shown to be unable to synthesize fatty acids or esterify cholesterol. The neutral lipids of S. citri grown in a medium containing horse serum consisted of free cholesterol, cholesteryl ester, free fatty acids, triglycerides and diglycerides. All polar lipids were phospholipids, with no glycolipids detected. These phospholipids, which are characteristic of many mycoplasmas, are phosphatidyl glycerol, diphosphatidyl glycerol, and their lyso derivatives. Sphingomyelin was also incorporated when cells were grown on horse serum. A sterol requirement for the growth of S. citri was confirmed using a serum-free medium supplemented with bovine serum albumin, palmitic acid, and various concentrations of sterols dissolved in Tween 80. The addition of palmitic acid stimulated growth but was not essential for growth. S citri was shown to grow best on cholesterol and beta-sitosterol and was able to grow on stigmasterol and ergosterol to a lesser degree. No growth was obtained using mevalonate, deoxycholate, or taurodeoxycholate as an alternative to sterol. S. citri was also able to grow when palmitic acid was replaced with oleic acid, linoleic acid, or linolenic acid. Alterations in the lipid composition of the growth medium and hence in the lipid composition of S. citri induced changes in the characteristic helical morphology of the cells, concurrent with loss of cell viability. Culture, age, and pH were also factors in determining cell morphology and viability.