bluuebunny/crossref_metadata_2025 huggingface dataset:
Cold hardening of raspberry plants in vitro is enhanced by increasing sucrose in the culture medium
Authors: Palonen Pauliina , Junttila Olavi
Published: March 2003

The influence of exogenously applied sucrose on cold hardening of raspberry (Rubus idaeus L.) in vitro was examined. Raspberry plants (cv. Preussen) were cultured on Murashige‐Skoog (MS) media with different levels (1, 3, 5 and 7%) of sucrose and subjected to low‐temperature acclimation (3/−3°C day/night temperature, 8‐h photoperiod) for 14 days. Cold hardiness (LT50 in controlled freezing), shoot moisture content, osmolality and the amounts of sucrose, glucose and fructose were determined. Exogenously applied sucrose was taken up by plants, but the uptake corresponded to less than 10% of total sugar reserves in the culture. Cold hardiness was primarily affected by acclimation treatment, but sucrose increased cold hardiness of nonacclimated plants and significantly enhanced the effect of acclimation treatment, 5% sucrose in the culture medium being optimal for cold hardening. LT50 values ranged between −4.1 and −7.1°C for nonacclimated, and between −14.2 and −20.7°C for cold‐acclimated shoots. Shoot moisture content was inversely related to medium sucrose level and declined only slightly during cold acclimation. After cold acclimation, plant osmolality predicted hardiness better than shoot moisture content. Plant osmolality and sugar content were increased by increasing the medium sucrose level and, to a greater extent, by cold acclimation. Sucrose, glucose and fructose accumulated during hardening. Sucrose was the predominant sugar, and the rate of sucrose accumulation during cold acclimation was independent of the medium sucrose level or the initial plant sucrose content. A close correlation between cold hardiness and total sugars, sucrose, glucose and fructose was established. These results suggest that sugars have more than a purely osmotic effect in protecting acclimated raspberry plants from cold.
A critical experimental evaluation of methods for determination of NH4+ in plant tissue, xylem sap and apoplastic fluid
Authors: Husted Søren , Hebbern Christopher A. , Mattsson Marie , Schjoerring Jan K.
Published: March 2003

Ammonium (NH4+) is a central intermediate in the N metabolism of plants, but the quantitative importance of NH4+ in transporting N from root to shoot and the capability of plants to store NH4+ in leaves are still matters of substantial controversy. This paper shows that some of these controversies have to be related to the use of inadequate analytical procedures used for extraction and quantification of NH4+ in plants. The most frequently used methods for determination of NH4+, viz. colorimetric methods based on the classical Berthelot reaction, suffered severely from interference caused by amino acids, amines, amides and proteins. For some of these metabolites the interference was positive, while for others it was negative, making correction impossible. Consequently, colorimetric analysis is inapplicable for determination of NH4+ in plants. Results obtained by ion chromatography may overestimate the NH4+ concentration due to co‐elution of NH4+ with amines like methylamine, ethylamine, ethanolamine and the non‐protein amino acid Γ‐aminobutyric acid. Derivatization of NH4+ with o‐phthalaldehyde at alkaline pH and subsequent quantification of NH4+ by fluorescence spectroscopy was also associated with interference. However, when pH was lowered to 6.8 during derivatization and 2‐mercaptoethanol was used as reductant, NH4+ could be determined with a high selectivity and sensitivity down to a detection limit of 3.3 μM in a 10‐μl sample volume. Derivatization was performed on‐line using a column‐less HPLC system, enabling rapid quantification of NH4+ in a few minutes. Flow injection analysis with on‐line gas dialysis was, likewise, free from interference, except when applied on highly senescent plant material containing volatile amines. Labile N metabolites in leaf tissue extract, xylem sap and apoplastic fluid were degraded to NH4+ during extraction and subsequent instrumental analysis if the samples were not stabilised. A simple and efficient stabilisation could be obtained by addition of 10 mM ice‐cold HCOOH to the plant extraction medium or to the samples of apoplastic fluid or xylem sap. We conclude that significant concentrations of NH4+, exceeding 1 mM, may occur in xylem sap, leaf apoplastic fluid and leaf tissue water of nitrate‐grown tomato and oilseed rape plants. The measured NH4+ concentrations were not a result of excessive N supplies, as even plants grown under mildly N‐deficient conditions contained NH4+.
Changes in antioxidative enzymes in cucumber cotyledons during natural senescence: comparison with those during dark‐induced senescence
Authors: Kanazawa S. , Sano S. , Koshiba T. , Ushimaru T.
Published: March 2003

Changes in 7 antioxidative enzymes in naturally senescent cotyledons of cucumber (Cucumis sativus) were investigated. The activities of superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6), dehydroascorbate reductase (EC 1.8.5.1) and glutathione reductase (GR; EC 1.6.4.2) gradually decreased during the progression of senescence, while those of ascorbate peroxidase (APX; EC 1.11.1.11) and guaiacol peroxidase (GPX; EC 1.11.1.7) gradually increased. The activity of monodehydroascorbate reductase (MDAR; EC 1.6.5.4) was not significantly changed. Western blot analysis showed that the protein level of mitochondrial SOD gradually declined. The protein level of catalase transiently decreased and then increased in the later stages of senescence, despite the decrease in its activity. The overall behavior was markedly different from that found in cotyledons of artificially senescing seedlings transferred into darkness; the activities of SOD, catalase, APX, GPX and GR gradually increased.
Expansion of cultured Zinnia mesophyll cells in response to hormones and light
Authors: Lee Sangkug , Woffenden Bonnie J. , Beers Eric P. , Roberts Alison W.
Published: March 2003

Mesophyll suspension cultures of Zinnia elegans L. have been used extensively to investigate the development of tracheary elements. Here we have modified the culture conditions to promote cell expansion and inhibit tracheary element differentiation and cell division. Cell expansion, measured by computer image analysis, was stimulated by auxin (α‐naphthyleneacetic acid), cytokinin (N6‐benzylaminopurine), gibberellic acid, brassinosteroid (24‐epibrassinolide), and light, all of which are known to promote cell expansion in whole plants or excised organs. Whereas light stimulated cell expansion primarily during the first 48 h of culture, auxin, cytokinin, gibberellic acid and brassinosteroid had little effect until after 48 h. Treatments also differed in their relative effects on cell elongation and radial cell expansion. Light and cytokinin had a greater effect on radial cell expansion, auxin and epibrassinolide promoted only cell elongation, and gibberellic acid had nearly equal effects on expansion in both directions. We have also shown by combining treatments that the effects of cytokinin and auxin are additive. Neither hormone treatment, however, was additive with the effect of light treatment. Finally, in contrast to xylogenic cultures where expansion occurs by tip growth, cell expansion in non‐differentiating cells was due to diffuse growth. These data show that cell expansion can be induced by hormones in primary mesophyll cultures from Zinnia in contrast to serially transferred plant suspension cultures. Furthermore, they indicate that auxin, cytokinin, and light induce cell expansion by different mechanisms in these cultures.
Comparison of five physiological parameters to assess the vitality of the lichen Ramalina lacera exposed to air pollution
Authors: Garty Jacob , Weissman Lior , Tamir Orly , Beer Sven , Cohen Yehudit , Karnieli Arnon , Orlovsky Lea
Published: March 2003

To determine the environmental impact of industrial activity, we examined and compared the following parameters of physiological integrity in the epiphytic fruticose lichen Ramalina lacera. (1) Potential quantum yield of PSII expressed as the chlorophyll fluorescence ratio Fv/Fm. (2) Spectral reflectance expressed as values of normalized difference vegetation index (NDVI). (3) Production of ethylene. (4) Electrolyte leakage brought about by degrading cell membranes in terms of electric conductivity. (5) The ratio A435nm/A415nm indicating the disintegration of chlorophyll. The amounts of Ba, Cu, K, Ni, S, V and Zn contained in the lichen thallus were measured to quantify the degree of pollution. Some of the lichen‐carrying twigs collected at a relatively unpolluted control site were resuspended on the original trees as controls. Other lichens were transplanted to 19 biomonitoring sites. Transplanted lichens in polluted sites contained higher amounts of Ba, Ni, S, V and Zn than lichens in the control site and in most of the rural sites upon an exposure period of 8 months. Statistical analysis revealed negative correlations between Fv/Fm ratios and Ba contents of transplants. High Ba, Cu, Ni and Zn contents correlated negatively with NDVI values. NDVI values correlated with A435nm/A415nm, Fv/Fm and K. The ratio A435nm/A415nm correlated positively with K and negatively with Ba, Cu and Zn. The production of ethylene correlated positively with Cu and Ba and negatively with A435nm/A415nm, Fv/Fm and NDVI. Electric conductivity values correlated positively with Ba, Cu, Na, S, V and Zn and negatively with NDVI. Both elemental content and physiological alterations in transplants of R. lacera point to a high degree of contamination in the Haifa Bay region, which is polluted by fuel‐oil combustion apart from other industrial activities. The present work suggests that in our specific study area, the most sensitive parameter to assess the vitality of the lichen thallus is electric conductivity whereas ethylene production is less sensitive.
Cold resistance in Antarctic angiosperms
Authors: Bravo León A. , Ulloa Nancy , Zuñiga Gustavo E. , Casanova Angélica , Corcuera Luis J. , Alberdi Miren
Published: March 2003

Deschampsia antarctica Desv. (Poaceae) and Colobanthus quitensis (Kunth) Bartl. (Cariophyllaceae) are the only two vascular plants that have colonized the Maritime Antarctic. The primary purpose of the present work was to determine cold resistance mechanisms in these two Antarctic plants. This was achieved by comparing thermal properties of leaves and the lethal freezing temperature to 50% of the tissue (LT50). The grass D. antarctica was able to tolerate freezing to a lower temperature than C. quitensis. The main freezing resistance mechanism for C. quitensis is supercooling. Thus, the grass is mainly a freezing‐tolerant species, while C. quitensis avoids freezing. D. antarctica cold acclimated; thus, reducing its LT50. C. quitensis showed little cold‐acclimation capacity. Because day length is highly variable in the Antarctic, the effect of day length on freezing tolerance, growth, various soluble carbohydrates, starch, and proline contents in leaves of D. antarctica growing in the laboratory under cold‐acclimation conditions was studied. During the cold‐acclimation treatment, the LT50 was lowered more effectively under long day (21/3 h light/dark) and medium day (16/8) light periods than under a short day period (8/16). The longer the day length treatment, the faster the growth rate for both acclimated and non‐acclimated plants. Similarly, the longer the day treatment during cold acclimation, the higher the sucrose content (up to 7‐fold with respect to non‐acclimated control values). Oligo and polyfructans accumulated significantly during cold acclimation only with the medium day length treatment. Oligofructans accounted for more than 80% of total fructans. The degrees of polymerization were mostly between 3 and 10. C. quitensis under cold acclimation accumulated a similar amount of sucrose than D. antarctica, but no fructans were detected. The suggestion that survival of Antarctic plants in the Antarctic could be at least partially explained by accumulation of these substances is discussed.
Correlation of resistance and H2O2 production in Ulmus pumila and Ulmus campestris cell suspension cultures inoculated with Ophiostoma novo‐ulmi
Authors: De Rafael M. A. , Valle T. , Babiano M. J. , Corchete P.
Published: March 2003

The Dutch elm disease (DED) pathogen Ophiostoma novo‐ulmi Buissm. elicited the production of H2O2 in cell suspension cultures of the resistant species Ulmus pumila L. This response was not observed in suspensions of the susceptible elm U. campestris Mill. H2O2 production started after a lag time of 30–40 min following inoculation, peaked between 4 and 6 h and lasted up to 24 h. Treatment of the suspensions with exogenously added H2O2 did not cause accumulation of the sesquiterpene phytoalexins mansonones nor of the coumarin scopoletin. Spore germination and growth of O. novo‐ulmi were significantly delayed with different amounts of H2O2 (0.1–1 mM). These results suggest that H2O2 production is an inducible defence response which may contribute to DED resistance by delaying the growth of the pathogen at the earliest stages of infection. Whether H2O2 is involved in other elm defence responses to the pathogen is presently unknown, but its production seems to be an independent event from phytoalexin formation.
Adjustments of net photosynthesis in Solanum tuberosum in response to reciprocal changes in ambient and elevated growth CO2 partial pressures
Authors: Sicher Richard C. , Bunce James A.
Published: March 2003

Single leaf photosynthetic rates and various leaf components of potato (Solanum tuberosum L.) were studied 1–3 days after reciprocally transferring plants between the ambient and elevated growth CO2 treatments. Plants were raised from individual tuber sections in controlled environment chambers at either ambient (36 Pa) or elevated (72 Pa) CO2. One half of the plants in each growth CO2 treatment were transferred to the opposite CO2 treatment 34 days after sowing (DAS). Net photosynthesis (Pn) rates and various leaf components were then measured 34, 35 and 37 DAS at both 36 and 72 Pa CO2. Three‐day means of single leaf Pn rates, leaf starch, glucose, initial and total Rubisco activity, Rubisco protein, chlorophyll (a+b), chlorophyll (a/b), α‐amino N, and nitrate levels differed significantly in the continuous ambient and elevated CO2 treatments. Acclimation of single leaf Pn rates was partially to completely reversed 3 days after elevated CO2‐grown plants were shifted to ambient CO2, whereas there was little evidence of photosynthetic acclimation 3 days after ambient CO2‐grown plants were shifted to elevated CO2. In a four‐way comparison of the 36, 72, 36 to 72 (shifted up) and 72 to 36 (shifted down) Pa CO2 treatments 37 DAS, leaf starch, soluble carbohydrates, Rubisco protein and nitrate were the only photosynthetic factors that differed significantly. Simple and multiple regression analyses suggested that negative changes of Pn in response to growth CO2 treatment were most closely correlated with increased leaf starch levels.
Lateral redistribution of auxin is not the means for gravitropic differential growth of coleoptiles: A new model
Authors: Edelmann Hans G.
Published: March 2003

Gravicurvature in water‐ and auxin (IAA)‐incubated coleoptiles of rye (Secale cereale L.) is similar, despite a general strongly enhancing effect of exogenous IAA on the overall (cell) elongation of these organs. Longitudinally split coleoptiles or isolated longitudinally halved coleoptiles (horizontally positioned as upper or lower halves) respond gravitropically in the same way as water‐incubated intact coleoptiles, irrespective of whether the halves are incubated in distilled water or IAA. A new model for the principal mechanism of regulation of gravitropic growth is proposed which depends on, yet does not involve, the redistribution of IAA as the means for gravistimulated differential growth, as postulated by the Cholodny‐Went hypothesis (CWH). It is based on a gravimediated temporarily restrained infiltration of IAA‐induced wall‐loosening factors into the growth‐limiting outer epidermal walls of the concave organ flank.
Importance of the cytochrome pathway of mitochondrial electron transport over the alternative pathway during the Kok effect in leaf discs of pea (Pisum sativum)
Authors: Padmavathi L. , Raghavendra A. S.
Published: March 2003

The Kok effect refers to the progressive light‐induced inhibition of dark respiration at low light intensities, which saturates around the light compensation point. This appears as a sudden break around the light compensation point in the plot of photosynthesis versus light intensity. The magnitude of the break can be considered as a measure of the Kok effect. In the present work, the importance of different components of dark respiration during the Kok effect was investigated by using low concentrations of mitochondrial inhibitors in leaf discs of pea (Pisum sativum L. cv. Azad P1). The effects of glucose (stimulates respiration) and 0.8 M sorbitol (imposes osmotic stress and inhibits photosynthesis) were also studied for comparison. The magnitude of the break decreased significantly in the presence of antimycin A or oligomycin (inhibitors of cytochrome pathway of mitochondrial electron transport and ATP synthase, respectively). In contrast, there was no significant change with salicylhydroxamic acid (SHAM; an inhibitor of alternative pathway of mitochondrial electron transport). The magnitude of the break increased significantly with glucose, and decreased on exposure to osmotic stress. Our results suggest that the Kok effect (inhibition of dark respiration in light) is modulated by inhibitors of cytochrome pathway and ATP synthesis, but not that of the alternative pathway.
Regulation of the expression of a putative ethylene receptor, PeERS2, during the development of passion fruit (Passiflora edulis)
Authors: Mita Satoru , Kawamura Syoichiro , Asai Tatsuo
Published: March 2003

We isolated a full‐length cDNA (PeERS2) that encoded the homologue in passion fruit of ERS1 of Arabidopsis and examined its expression during development of passion fruit. PeERS2 was 2357 bp long and included a single open reading frame that encoded a putative protein of 634 amino acids with a calculated molecular mass of 70.8 kDa. Expression of PeERS2 mRNA in arils of passion fruit was enhanced during ripening and after treatment with ethylene, but its level remained very low in seeds over the course of ripening. Accumulation of PeERS2 mRNA in arils was markedly reduced in fruits treated with 2,5‐norbornadiene (NBD), but simultaneous application of ethylene abolished the inhibitory effects of NBD, suggesting that the continuous action of ethylene might promote ripening, with a concomitant increase in the abundance of PeERS2 mRNA. Levels of transcripts of the PeERS1 and PeERS2, which encode similar but not identical receptors for ethylene, increased during senescence of flowers and expression of PeERS2 mRNA was also enhanced during formation of the separation layer. The levels of transcripts of PeETR1 (the gene for yet another ethylene receptor) and PeERS1 were, respectively, higher than those of PeERS2 in sepals and ovaries. The transcripts of all three genes for ethylene receptors were barely detectable in anthers. These results suggest that the expression of the three genes for ethylene receptors is differentially regulated and that expression of the gene for PeERS2 is regulated not only by ethylene itself but also by developmental factors. Expression of each of the three individual genes for ethylene receptors might be controlled by different molecular mechanisms in the various tissues.
Regulation of the tetrapyrrole biosynthetic pathway leading to heme and chlorophyll in plants and cyanobacteria
Authors: Vavilin Dmitrii V. , Vermaas Wim F. J.
Published: March 2003

Photosynthetic organisms synthesize chlorophylls, hemes, and bilin pigments via a common tetrapyrrole biosynthetic pathway. This review summarizes current knowledge about the regulation of this pathway in plants, algae, and cyanobacteria. Particular emphasis is placed on the regulation of glutamate‐1‐semialdehyde formation and on the channelling of protoporphyrin IX into the heme and chlorophyll branches. The potential role of chlorophyll molecules that are not bound to photosynthetic pigment‐protein complexes (‘free chlorophylls’) or of other Mg‐containing porphyrins in regulation of tetrapyrrole synthesis is also discussed.
Importance of methionine biosynthesis for Arabidopsis seed germination and seedling growth
Authors: Gallardo Karine , Job Claudette , Groot Steven P. C. , Puype Magda , Demol Hans , Vandekerckhove Joël , Job Dominique
Published: March 2003

Proteomics of Arabidopsis seeds revealed the differential accumulation during germination of two housekeeping enzymes. The first corresponded to methionine synthase that catalyses the last step in the plant methionine biosynthetic pathway. This protein was present at low level in dry mature seeds, and its level was increased strongly at 1‐day imbibition, prior to radicle emergence. Its level was not increased further at 2‐day imbibition, coincident with radicle emergence. However, its level in 1‐day imbibed seeds strongly decreased upon subsequent drying of the imbibed seeds back to the original water content of the dry mature seeds. The second enzyme corresponded to S‐adenosylmethionine synthetase that catalyses the synthesis of S‐adenosylmethionine from methionine and ATP. In this case, this enzyme was detected in the form of two isozymes with different pI and Mr. Both proteins were absent in dry mature seeds and in 1‐day imbibed seeds, but specifically accumulated at the moment of radicle protrusion. Arabidopsis seed germination was strongly delayed in the presence of dl‐propargylglycine, a specific inhibitor of methionine synthesis. Furthermore, this compound totally inhibited seedling growth. These phenotypic effects were largely alleviated upon methionine supplementation in the germination medium. The results indicated that methionine synthase and S‐adenosylmethionine synthetase are fundamental components controlling metabolism in the transition from a quiescent to a highly active state during seed germination. Moreover, the observed temporal patterns of accumulation of these proteins are consistent with an essential role of endogenous ethylene in Arabidopsis only after radicle protrusion.
Cell wall‐degrading enzymes and pectin solubility and depolymerization in immature and ripe watermelon (Citrullus lanatus) fruit in response to exogenous ethylene
Authors: Karakurt Yasar , Huber Donald J.
Published: March 2003

Watermelon fruit have been shown to be extremely sensitive to exogenous ethylene, exhibiting acute symptoms of whole‐fruit softening and placental‐tissue water‐soaking following short periods of exposure to the gas. This study addressed the firmness, specific activities of cell wall hydrolases, and solubility and molecular mass properties of polyuronides in placental tissue in response to treatment of intact fruit with ethylene. Watermelon fruit were harvested at the immature and full‐ripe stages and exposed to 50 µl l−1 ethylene for 6 days at 20°C. The firmness of placental tissue from ethylene‐treated ripe and immature fruit decreased nearly 80% during 6 days of ethylene exposure, whereas the firmness of placental tissue from fruit maintained in air remained relatively constant up to day 3 and then decreased slightly (12%) during the following 3 days of storage. Although ethylene treatment in some cases influenced the levels of extractable placental‐tissue polygalacturonase (EC 3.2.1.15), pectinmethylesterase (EC 3.2.1.11), and α‐(EC 3.2.1.22) and β‐galactosidase (EC 3.2.1.23) specific activities, these effects were not observed for fruit of both developmental stages and appeared not to be directly involved in the water–soaking syndrome. Symptoms of water‐soaking were accompanied by increases in the levels of water‐ and CDTA (trans‐1,2‐cyclohexanediamine‐N,N,N',N′‐tetraacetic acid)‐soluble polyuronides and significant molecular mass downshifts in polyuronides in both immature and ripe watermelon fruit. Polyuronide depolymerization in ethylene‐treated ripe fruit was extensive. The parallel trends of enzyme changes in ethylene‐ compared with air‐treated fruit indicate that extractable enzyme levels are not associated with development of the water‐soaking disorder. The potential involvement of membrane dysfunction in the water‐soaking phenomenon is discussed.
Prevention and treatment of cytomegalovirus infection in organ transplant recipients
Authors: Kusne S. , Shapiro R. , Fung J.
Published: March 2003

Cytomegalovirus (CMV) is the most common viral pathogen in organ transplant recipients. The patients at highest risk of developing CMV disease are seronegative recipients of seropositive donors, and seropositive recipients who receive antilymphocyte agents such as OKT3 and antithymocyte globulin (ATG) for induction or for rejection. There have been many trials of CMV prevention, but they are difficult to compare with one another because of variability in definitions and end points. Two modalities that have been used to prevent CMV disease are prophylaxis and preemptive therapy. In prophylaxis all patients are given an antiviral agent in order to prevent CMV disease, while in preemptive therapy (also called targeted prophylaxis) only patients who are identified as ‘high risk’ are selected for treatment. Selected trials of prophylaxis and preemptive therapy in solid‐organ recipients are reviewed. The factors to be considered in using one modality or the other are side effects from antivirals, cost of monitoring and antivirals, efficacy of the two modalities, and potential emergence of drug resistance.

Sensitive tests that have been used for early diagnosis and monitoring of CMV are antigenemia and the polymerase chain reaction (PCR). Antigen pp65 is a lower matrix protein and can be detected in peripheral blood leukocytes. The sensitivity and specificity are high and vary from 89% to 100% and 92% to 96%, respectively. Currently, many authors believe that the antigenemia test is more useful than the PCR test. The antigenemia test is useful for viral monitoring as a guide for preemptive therapy after organ transplantation. Persistence of high counts of antigenemia may indicate inadequate antiviral therapy or emergence of resistance. Recurrence of positive antigenemia after treatment of CMV disease can be a sign of relapse. Transplant patients who develop resistance to antiviral drugs are usually seronegative recipients who receive an organ from a seropositive donor and have several courses of antivirals for CMV disease. Ganciclovir is the most frequent antiviral agent used in transplant recipients and is usually well tolerated. Resistance to ganciclovir may occur and is usually secondary to virus mutation in the UL97 gene. The availability of sensitive diagnostic tests such as pp65 antigenemia has made the early diagnosis of CMV possible in organ transplant recipients. CMV is being treated much earlier now, and progression to disseminated disease is uncommon. Prudent use of antiviral drugs will hopefully limit the problem of drug resistance.
Epidemiology of fungal infections in solid organ transplant patients
Authors: Patterson J.E.
Published: March 2003

The epidemiology of fungal infection in solid organ transplant patients is of concern due to the high mortality associated with this complication. Rates of fungal infections vary by type of transplant recipient. Most of these infections occur two to six months after transplantation. Liver transplant recipients are more likely to have early fungal infection which is often due to Candida species. Exogenous and endogenous Candida infection may occur in the immunosuppressed patient in the intensive care unit. Patients with chronic rejection are more likely to have late infection (after six months) which may be due to Aspergillus or endemic fungi such as Cryptococcus. Lung and heart–lung transplant recipients are more predisposed to infection with Aspergillus and other filamentous fungi, due to exposure of the transplanted organ to the external environment. Preventative measures such as environmental controls and chemoprophylaxis may be beneficial in high‐risk patients. Emerging fungal pathogens such as the dematiaceous fungi may cause skin or soft tissue infection, or more serious systemic infections. Fungal infection should be ruled out in the solid organ transplant patient with early brain abscess. Characteristic risk factors in high‐risk types of solid organ transplant recipients should be recognized for early diagnosis and treatment of these infections associated with high morbidity and mortality.
Listeria monocytogenes tricuspid valve endocarditis with septic pulmonary emboli in a liver transplant recipient
Authors: Avery R.K. , Barnes D.S. , Teran J.C. , Wiedemann H.P. , Hall G. , Wacker T. , Guth K.J. , Frost J.B. , Mayes J.T.
Published: March 2003

Listeria monocytogenes has long been known as a pathogen of immunocompromised hosts, including solid organ and bone marrow transplant recipients. Its principal manifestations include bacteremia and meningitis. Endocarditis due to Listeria is far less common and in general affects the left side of the heart. We here report an unusual case of Listeria tricuspid valve endocarditis and septic pulmonary emboli in a sulfa‐intolerant liver transplant recipient with a history of relapsing cytomegalovirus (CMV) hepatitis and an indwelling Hickman catheter. The literature on Listeria endocarditis and infections in transplant recipients is reviewed. The possible relationship between susceptibility to Listeria infection and the discontinuation of trimethoprim‐sulfamethoxazole prophylaxis is of interest.
Tuberculosis isolated to the renal allograft
Authors: Lorimer I. , Botha J. , Pontin A.R. , Pascoe M.D. , Kahn D.
Published: March 2003

Immunosuppressed patients after renal transplantation are at increased risk of developing infective complications, including tuberculosis. We describe four renal transplant patients who presented with tuberculosis isolated to the renal allograft. The three patients with adequate follow‐up presented with a febrile illness 12–26 months after the transplant. The mycobacterial infection was found in the graft nephrectomy specimen in three patients. One patient with renal allograft dysfunction had a percutaneous biopsy that showed tuberculosis. The latter patient recovered renal allograft function after anti‐tuberculous therapy. None of the patients had evidence of tuberculosis elsewhere. We conclude that tuberculosis isolated to the renal allograft, especially in an endemic area, may be the cause of renal dysfunction, and appropriate therapy could lead to salvage of the graft.
Atypical presentation of Madurella mycetomatis mycetoma in a renal transplant patient
Authors: Meis J.F.G.M. , Schouten R.A. , Verweij P.E. , Dolmans W. , Wetzels J.F.M.
Published: March 2003

A renal transplant patient presented with a swelling on his foot. Fungal hyphae were found in the abscess, and culture demonstrated Madurella mycetomatis, an agent of mycetoma. There were no black grains in the pus and no overlying sinuses. This was an atypical presentation of maduromycosis in a renal transplant patient.
The diverse pathology of post‐transplant lymphoproliferative disorders: the importance of a standardized approach
Authors: Nalesnik M.A.
Published: March 2003

Abstract:Post‐transplant lymphoproliferative disorders (PTLD) are a diverse group of abnormal lymphoid growths that include both hyperplasias and neoplasias. They have been divided into several general pathologic categories that have prognostic significance. These include early or hyperplastic PTLD, polymorphic PTLD, and lymphomatous or monomorphic PTLD. The majority of PTLDs are of B‐cell origin and contain Epstein–Barr virus (EBV). However, PTLDs of T‐ or NK‐cell origin have been described, and late‐arising EBV‐negative lymphoid tumors are becoming more frequently reported in this population. Other lymphoid neoplasms, such as those arising from mucosal‐associated lymphoid tissue (MALTomas), have recently been recognized in transplant patients, and their relationship to PTLD is uncertain. Multicentric PTLD may represent either advanced‐stage disease or multiple independent primary tumors. Likewise, recurrent PTLD may represent true recurrence or the emergence of a second primary tumor. Transplant patients are also at risk for other opportunistic neoplasms, including EBV‐associated leiomyosarcomas that may be seen alone or in conjunction with PTLD. This underscores the necessity for pathologic diagnosis of mass lesions in this patient population. The pathologist should strive to categorize the form of post‐transplant lymphoproliferation in accordance with currently accepted criteria. The diagnosis should incorporate the histopathologic appearance, cell phenotype, clonal status, and EB viral status. The pathologist may play a special role in guiding therapy by ascertaining the presence of such markers as CD20 on tumor cells. Specialized techniques, such as molecular analysis of oncogenes/tumor suppressor genes and evaluation of host:donor status of PTLD, may play important roles in diagnostic evaluation in the future.
The role of neutrophils in the pathogenesis of obliterative bronchiolitis after lung transplantation
Authors: Elssner A. , Vogelmeier C.
Published: March 2003

Abstract: Obliterative bronchiolitis (OB) represents the most important long‐term complication after lung transplantation. Elevated numbers of neutrophils within the airways are a hallmark of OB. It is unclear what causes the recruitment and activation of neutrophils in the airways of patients with OB: the process of chronic rejection itself or infection, which may (especially in latent virus infection) often be overlooked by the currently applied diagnostic procedures. It is well known that besides their physiologic functions in the clearance of invading micro‐organisms, activated neutrophils have a remarkable potential to cause damage to lung tissue. This is attributable to their capability to generate reactive oxygen species and to release potentially toxic proteases. It has been shown that the increased numbers of neutrophils in bronchoalveolar lavage fluid of patients with bronchiolitis obliterans syndrome (BOS) after lung transplantation are associated with elevated levels of interleukin‐8, the predominant neutrophil chemotactic factor in the lung. As evidence for the impact of neutrophils on the pathogenesis of BOS, there is significant oxidative stress within the airways of patients with BOS. In addition, the milieu within the airways is characterized by an imbalance between neutrophil elastase (NE) and molecules that inhibit NE as a result of an increased burden of NE released by neutrophils. A defective antiprotease shield due to the loss of secretory leukoprotease inhibitor could be demonstrated in BOS. These mechanisms may provide possible targets to develop new therapeutic strategies that either prevent neutrophil sequestration and activation, or inhibit neutrophil products in order to prevent or attenuate airway damage.
Open lung biopsy in bone marrow transplant recipients has a poor diagnostic yield for a specific diagnosis
Authors: Shaikh Z.H.A. , Torres H.A. , Walsh G.L. , Champlin R.E. , Kontoyiannis D.P. , Shaikh Z.H.A. , Torres H.A. , Walsh G.L. , Champlin R.E. , Kontoyiannis D.P.
Published: March 2003

Abstract: The diagnostic yield of open lung biopsy (OLB) in bone marrow transplantation (BMT) recipients having pulmonary infiltrates has not been evaluated recently. Therefore, we reviewed our 2‐year experience (1998–99) with such patients at The University of Texas M. D. Anderson Cancer Center. We found 12 BMT recipients who underwent OLB analysis for the evaluation of pulmonary infiltrates. A treatable infectious etiology leading to the initiation or modification of antimicrobial agent administration was found in only two patients having bilateral nodular disease and one having bilateral parenchymal infiltrates. We conclude that OLB in BMT patients having diffuse pulmonary infiltrates has a low diagnostic yield for treatable infectious etiologies.
Rat‐to‐mouse small bowel xenotransplantation: A novel model for studying acute vascular and hyperacute xenograft rejection and xenogenic cell migration
Authors: Kiyochi Hidenori , Kellersmann Richard , Blömer Anna , Garcia Bertha M. , Zhang Zheng , Zhong Robert , Grant David R.
Published: March 2003

Kiyochi H, Kellersmann R, Blömer A, Garcia BM, Zhang Z, Zhong R and Grant DR.

Rat‐to‐mouse small bowel xenotransplantation: A novel model for studying acute vascular and hyperacute xenograft rejection and xenogenic cell migration. Xenotransplantation 1999; 6: 00‐00.

©Munksgaard, Copenhagen

Abstract: The present study was undertaken to establish a rat‐to‐mouse vascularized small bowel xenotransplantation model to study acute vascular and hyperacute xenograft rejection, and xenogenic cell migration. Lewis rat small bowel grafts were transplanted heterotopically to group 1, Balb/c mice, and group 2, Balb/c mice pre‐sensitized with a donor spleen cell injection. The grafts were examined by serial pathology and flow cytometry. In group 1, acute vascular rejection was present by the 5th post‐operative day (POD). Immunohistology showed a strong endothelial deposition of IgG, IgM and C3, associated with a minimal lymphocytic infiltrate. There was a vigorous cell migration from the recipient to the graft, in which recipient origin cells comprised 80.1± 6.9% of the graft mesenteric lymph node by POD 3. However, there was almost no cell migration from the graft to the recipient. The intestinal xenografts in the group 2 showed massive hemorrhage, fibrin deposition, vascular congestion and thrombosis 60 min after transplantation. IgG and C3 were present on the endothelium as early as 1 min after reperfusion. The vigorous humorally‐mediated vascular damage and rapid elimination of donor cells seen with intestinal xenograft rejection are distinct from the usual picture of allograft rejection. Hyperacute rejection can be induced by recipient pre‐sensitization with donor spleen cells. The potential advantages of studying xenotransplantation in this model include: (1) the wide range of immunologic reagents available for mice; (2) the opportunity to study the progression of vascular damage easily by performing serial biopsies in the same animal; and (3) the opportunity to study, in vivo, two‐way cellular response by examining cell trafficking in the mesenteric lymph nodes.
Xenogeneic islet transplantation
Authors: Simeonovic Charmaine J.
Published: March 2003

Simeonivic C J. Xenogeneic islet transplantation. Xenotransplantation 1999; 6: 00‐00. ©Munksgaard, Copenhagen.
Role of UW solution and sodium nitroprusside in reperfusion of liver xenografts from guinea‐pig to rat
Authors: Miki Toshio , Subbotin Vladimir , Goller April L. , Tandin Alessia , Rao Abdul S. , Fung John J. , Valdivia Luis A.
Published: March 2003

Guinea‐pig livers are poorly reperfused when transplanted into rats. We have observed that, in contrast to that of the rat, the guinea‐pig intrahepatic portal vein (PV) has a thick layer of smooth muscle. It is possible that, after perfusion of the liver with ice‐cold saline, this could go into spasm, resulting in poor reperfusion. To test this hypothesis, guinea‐pig livers were perfused with different solutions stored at varying temperatures and transplanted into LEW rats. To prevent xenograft hyperacute rejection, all xenograft recipients were treated with 80 U/kg cobra venom factor (CVF) i.v. on days –1 and 0. In addition to the percentage reperfusion, PV resistance and recipient survival were also monitored. In group I, liver xenografts perfused with ice‐cold saline (4°C) reperfused poorly (20–30%), resulting in the development of portal hypertension (16.5 cmH2O vs. 12 cmH2O in naive LEW rats) and shortened mean survival time (11.7 ± 4.2 h). In contrast, group II livers perfused with saline at room temperature (23°C) underwent homogeneous reperfusion (98–100%) with no increase in portal vein resistance, indicating that low temperature was the main trigger for the spasm of the PV. Moreover, recipient survival in this group was significantly prolonged to a mean of 22 ± 2.6 h (P < 0.01). Although UW solution (group III) and the vasodilator sodium nitroprusside (NP) (group IV) when used alone improved the degree of hepatic reperfusion, it was still not optimal. The supplementation, however, of UW solution with NP in group V animals resulted in homogeneous reperfusion (98%) with no portal hypertension and consistent prolonged graft survival of 21.0 ± 1.7 h. Therefore, this study has determined that the riddle of the abnormal reperfusion of guinea‐pig liver xenografts by rat blood is non‐immune mediated and is due to the spasm of the strong smooth muscle in the PV tree produced by cold perfusates.
The effect of macrophage depletion on delayed xenograft rejection: studies in the guinea pig‐to‐C6‐deficient rat heart transplantation model
Authors: Wu Guosheng , Korsgren Olle , Van Rooijen Nico , Wennberg Lars , Tibell Annika
Published: March 2003

The purpose of this study was to investigate the effect of macrophage depletion, using liposome‐encapsulated dichloromethylene diphosphonate (Lip‐Cl2MDP), on delayed xenograft rejection (DXR) in the guinea pig‐to‐C6‐deficient rat heart transplantation model. In this model, hyperacute rejection does not occur, but, in untreated recipients, xenografts are still destroyed by DXR within 1–2 days. Graft survival was 68 ± 8.4 h in splenectomized control rats, 77 ± 16.3 h with Lip‐Cl2MDP alone, 99 ± 10.4 h with deoxysperguarlin (DSG; P < 0.01 vs. controls), and 127 ± 19.4 h with Lip‐Cl2MDP plus DSG (P < 0.01 vs. DSG alone). Treatment with DSG alone or in combination with Lip‐Cl2MDP resulted in significant reductions in serum IgM levels at rejection. Immunohistological studies showed that Lip‐Cl2MDP alone or in combination with DSG reduced infiltration of grafts by both ED1 + and ED2 + macrophages. These experiments support the concept that macrophages play an important role in DXR and suggest that strategies targeting macrophages may be useful in controlling DXR.
Differential expression of Galα1,3Gal epitopes on fetal and adult porcine hematopoietic cells
Authors: Gojo S. , Harper D. , Down J. , Awwad M. , Cooper D.K.C.
Published: March 2003

Galα1‐3Gal (Gal) is the major epitope on pig tissues bound by human natural antibodies. Xenogeneic hematopoietic cell transplantation is being investigated to induce immunological tolerance to xenografts. We have investigated the level of Gal expression on pig hematopoietic cells. Cells were collected from pig fetal liver and bone marrow (BM), and also from adult BM and peripheral blood, before and after treatment with pig‐specific hematopoietic growth factors. Fluorescent activated cell sorting (FACS) analysis was performed with the M86 monoclonal antibody (specific for Gal), lineage markers, and biotinylated stem cell factor (SCF) to detect c‐kit expression. In fetal pig BM and liver, there was no significant difference in Gal expression between monocytes/macrophages (myeloid cells) and lymphocytes. In adult hematopoietic cells from all sources, Gal‐positive subpopulations in T cells showed weak expression of Gal, whereas B cells demonstrated higher expression, and myeloid cells showed highest expression. Adult BM and mobilized peripheral blood progenitor cells contained small populations with very low or negligible expression of Gal. A very small population of c‐kit‐positive cells, indicating progenitor cells, were Gal‐negative. The small Gal‐negative population that exists in progenitor cells might explain why some pig colony forming units (CFU) can be resistant to human serum.
Morphospatial analysis of soft‐tissue profile in patients with Class II division 1 malocclusion treated using twin block appliances: geometric morphometrics
Authors: Singh GD
Published: March 2003

Author– Singh GD

Objectives– To study soft‐tissue profile changes in patients treated with twin block appliances (TBA) for the correction of Class II division 1 malocclusion. The null hypothesis is that soft‐tissue profiles do not show any significant improvements associated with TBA treatment.

Design– Longitudinal, retrospective.

Setting and Sample Population– Scotland, UK, using lateral cephalographs of 46 consecutive, prepubertal children (aged 9–11 years) and 55 adolescents (aged 12–14 years) obtained from an orthodontic practice.

Experimental Variable– The prepubertal children underwent ≈13 months of TBA treatment, while the adolescents underwent ≈22 months of treatment.

Outcome Measures– Configurations of 13 digitized homologous landmarks of pre‐ and post‐treatment soft‐tissue facial profiles were compared using cephalometry, Euclidean distance matrix analysis (EDMA) and thin plate spline (TPS) analysis.

Results– Cephalometry showed that height increases associated with the TBA were in the labiomental areas, and the most significant height decreases were seen in the lip regions. The results of EDMA also indicated significant changes (P < 0.05). The distance between the lips decreased by >5%, with increases in length in the labiomental region. The TPS analysis showed the soft‐tissues of the mandibular complex being displaced antero‐inferiorly, with anterior displacement of the landmarks of the lip region. These changes showed that the lips were brought into closer proximity with each other, permitting a functional oral seal. Moreover, the labiomental groove became less pronounced, reflecting the underlying dento‐alveolar correction.

Conclusion– Demonstrable improvements in soft‐tissue facial profile may be associated with TBA treatment.
Atypical expression of cleidocranial dysplasia: clinical and molecular‐genetic analysis
Authors: Golan I , Baumert U , Wagener H , Dauwerse J , Preising M , Lorenz B , Niederdellmann H , Müßig D
Published: March 2003

Cleidocranial dysplasia (CCD) and the Rubinstein–Taybi syndrome (RTS) are two rare congenital syndromes that have many clinical signs in common. We present an 18‐year‐old‐patient with untypical CCD expression who was misdiagnosed with RTS at the age of 2 years. An extensive craniofacial examination was carried out with respect to morphological and dental aspects. The molecular‐genetic analysis of two underlying genes (CBFA1 and CBP) for CCD and RTS was performed using SSCP, direct sequencing and FISH.

While the clinical examination showed uncharacteristic CCD symptoms with some findings common for RTS, the molecular‐genetic analysis revealed a missense mutation in the CBFA1 gene, which is considered to be the etiological factor for CCD. Our findings with this patient presented clear evidence for the wide morphologic variety that can be related to a certain gene such as CBFA1. The diagnosis of rare diseases is currently based on the clinical phenomenology of small groups or single cases. The use of molecular‐genetic biology extends the horizon of diagnostic and scientific possibilities. In this patient, it allowed us to compare the clinically diagnosis to molecular‐genetic data. We conclude that molecular‐genetic analysis may be a helpful tool in the differential diagnosis of many congenital diseases such as CCD and RTS.