Treatment of childhood Wilms' tumor without radiotherapy in Nicaragua

BACKGROUND

Recent trends in therapeutic strategies for Wilms' tumor are based on an attempt to reduce or omit radiotherapy (RT) in a sizable fraction of patients. We report here the clinical and histological features as well as the results obtained in 37 children (23 males, 14 females; median age at diagnosis 3 years, range 0.8-8 years) diagnosed between 1991 and 1996, and treated with chemotherapy (CT) and surgery at La Mascota Hospital, Managua, Nicaragua.

PATIENTS AND METHODS

Patients were grouped as follows: those who underwent surgery at diagnosis (group A, n = 4), patients who received preoperative CT because of large tumor size (group B, n = 27), lung metastases (n = 5) or bilateral disease (n = 1) (group C, n = 6). Treatment consisted of vincristine (VCR) and actinomycin-D (ACTD) for 24 weeks in group A, and of VCR, ACTD and adriamycin for 68 weeks in groups B and C. Histology was classified as favorable in 30 patients (81%), unfavorable in six patients (all of group B) and unknown in one.

RESULTS

With a median follow-up time of 6.4 years the event-free survival for the whole group was 80.1%+/-6.8 (SE). No event occurred beyond 5 years of diagnosis.

CONCLUSIONS

These results suggest that RT does not appear necessary for the majority of patients, and that an excellent surgical approach associated with an intensive CT schedule can control the disease, even in the absence of adequate information on the intra-abdominal tumor extent.

Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species

Clinical response to supervised treatment of Colombian patients with cutaneous leishmaniasis was evaluated in a randomized controlled trial comparing 10 days versus 20 days of treatment with meglumine antimonate (20 mg Sb/kg/day). Masked examiners evaluated clinical response defined as 100% re-epithelialization of all lesions at 13 weeks and no relapses during 52 weeks of follow-up. The efficacy of meglumine antimonate for 10 days' treatment was 61% (28 of 46) compared to 67% (24 of 36) for 20 days. There was a significantly lower clinical response for children < 5 years in both 10-day (11%) and 20-day (25%) groups compared to patients aged 5-14 years (67% and 75%, respectively) and 15 years or more (81% and 83%, respectively). Overall efficacy of treatment schedules was comparable, but lower than expected, mainly because of low efficacy in children. Pathogenicity of infection and pharmacokinetics may affect the treatment response in children. New therapeutic alternatives should be evaluated in trials that include children and women.

Prediction, identification, and artificial selection of DNA rearrangements in Rhizobium: toward a natural genomic design

Based on the DNA sequence of the symbiotic plasmid of Rhizobium strain NGR234, we predicted potential rearrangements generated by homologous recombination. All predicted rearrangements were identified experimentally by using a PCR-based methodology. Thus, the predicted and the actual dynamic maps of the replicon coincide. By using an approach that does not involve the introduction of exogenous genetic elements, derivative populations that are pure for specific rearrangements were obtained. We propose that knowledge of the DNA sequence of a genome offers the possibility of designing pathways of sequential rearrangements leading to alternative genomic structures. An experimental strategy to isolate bacterial populations containing the desired structures is discussed.

In Rhizobium etli symbiotic plasmid transfer, nodulation competitivity and cellular growth require interaction among different replicons

Bacteria belonging to the genus Rhizobium are able to develop two different lifestyles, in symbiotic association with plant roots or through saprophytic growth. The genome of Rhizobium strains is constituted by a chromosome and several large plasmids, one of them containing most of the genes involved in symbiosis (symbiotic plasmid or pSym). Our model strain Rhizobium etli CFN42 contains six plasmids. We have constructed multiple plasmid-cured derivatives of this strain and used them to analyze the contribution of these plasmids to free-living cellular viability, competitivity for nodulation, plasmid transfer, and utilization of diverse carbon sources. Our results show that the transfer of the pSym is strictly dependent on the presence of another plasmid; consequently under conditions where pSym transfer is required, nodulation relies on the presence of a plasmid devoid of nodulation genes. We also found a drastic decrease in competitivity for nodulation in multiple plasmid-cured derivatives when compared with single plasmid-cured strains. Cellular growth and viability were greatly diminished in some multiple plasmid-cured strains. The utilization of a number of carbon sources depends on the presence of specific plasmids. The results presented in this work indicate that functional interactions among sequences scattered in the different plasmids are required for successful completion of both lifestyles.

Prevalence of sensitization to Tetranychus urticae in greenhouse workers

BACKGROUND

Tetranychus urticae (TU) is a macroscopic mite which infests a large number of plants of economic interest worldwide. It has recently been described as a cause of occupational allergic disease in greenhouse workers. However, there are no epidemiological data concerning the prevalence of TU allergy in an unselected exposed population.

OBJECTIVE

The aims were to study the prevalence of TU sensitization among greenhouse workers and its relationship to the working environment and to personal factors.

METHODS

We studied 246 consecutive greenhouse workers, recruited directly from the field. A clinical and epidemiological questionnaire, a skin-prick test (SPT) to TU and common allergens and TU-specific IgE (RAST) determinations were performed. Seventy-five healthy volunteers and 152 atopic patients were used as a control group.

RESULTS

The prevalence of a positive SPT to TU was of 25%. Forty-five workers (19%) were TU-allergic, occurring more often in atopic greenhouse workers (P < 0.0001). Seven per cent showed asymptomatic sensitization. The time of exposure to TU was significantly greater in the TU-allergic patients (P < 0.05). The probability of sensitization to TU was 3.7 times greater in exposed than in non-exposed subjects (P < 0.0001).

CONCLUSIONS

In this study, the prevalence of TU sensitization was 25%. There were significant associations with TU allergy and atopy and the time of exposure to TU.

Cross-reactions between Dermatophagoides pteronyssinus and Dermatophagoides farinae (Acari: Pyroglyphidae) related to the different growth phases of cultures

The allergenic cross-reactivity of both inter- and intraspecies of house dust mites, Dermatophagoides pteronyssinus (Trouessart, 1897) and Dermatophagoides farinae Hughes, 1961, taking into account the allergenic differences that exist throughout the growth curves, was evaluated by means of RAST-inhibition, using sera from patients allergic to these mites. The results demonstrate that extracts obtained from mite cultures during the maximum exponential growth phase are the best source of reagents to better discriminate cross-reactivity studies. The analyses obtained from this work, together with those obtained in previous reports, help to define the ideal conditions related to the allergenic diversity, avidity, and cross-reactivity of specific antibodies for the elaboration of allergenic extracts as a tool for use in diagnosis and specific treatment of IgE-mediated hypersensitivity caused by house dust mites.

Quantification of profilins by a monoclonal antibody-based sandwich ELISA

Profilins are plant allergens responsible for cross-reactivities in pollen and fruit-allergic patients. A two-site enzyme-linked immunosorbent assay has been developed for the quantification of profilins and its suitability for quantifying profilin in different plant extracts has been evaluated. The assay is based on two profilin-specific monoclonal antibodies (mAbs) with different epitope specificities. These antibodies were immobilized on ELISA plates and incubated with samples containing profilin. Bound profilin was detected by a combination of biotinylated profilin-specific antiserum and peroxidase-streptavidin conjugate. The optimized ELISA measured profilin concentrations ranging from 4 to 250 ng/ml and could quantify profilins from plant species of a variety of different botanical families. No reactivity to mites, molds, or crustaceans was detected, suggesting that the immunoassay is plant-specific. The results indicate that this sensitive profilin-assay will be helpful both for quantifying the profilin content of allergenic extracts intended for clinical use and for studying cross-reactivities between pollen extracts.

Pollen allergy in peach-allergic patients: sensitization and cross-reactivity to taxonomically unrelated pollens

BACKGROUND

Fruit allergy has been attributed to cross-reactive IgE to pollens and has been associated with a particular pollen sensitization.

OBJECTIVE

The aim of the study was to evaluate sensitization to several taxonomically unrelated pollens in peach- and pollen-allergic patients and to study cross-reactivity between them.

METHODS

One hundred sixty-five patients were evaluated: 70 peach- allergic patients together with 95 pollen-allergic patients (control group). Pollen skin tests in duplicate were performed to 5 grasses, 8 trees, and 7 weeds. Cross-reactivity between peach and taxonomically diverse pollens was determined by radioallergosorbent inhibition and Western blot inhibition tests. Experiments were also carried out after preadsorption of the sera with purified natural profilin.

RESULTS

The skin test results revealed that peach-allergic patients frequently reacted to most pollens-grasses, weeds, and trees-even when some of these are not found in our geographic area. There was a statistically significant increase in sensitization frequency to most trees and weeds, with a statistically higher occurrence of asthma (odds ratio 2.98, 95% confidence interval 1.46-6.09). Inhibition test results provided evidence that taxonomically unrelated grasses, weeds, and trees produced various and substantial degrees of inhibition in specific IgE to peach and that the peach extract elicited strong inhibitions to those pollens. Profilin was found to be a relevant cross-reactive antigen in these patients.

CONCLUSION

The results of this study provide evidence that peach allergy is linked to sensitization to several taxonomically unrelated pollens. This is attributable to the ubiquitous nature of the IgE binding determinants-such as profilins-between peach and taxonomically unrelated pollens.

Positive IgG Western blot for Borrelia burgdorferi in Colombia

In order to evaluate the presence of specific IgG antibodies to Borrelia burgdorferi in patients with clinical manifestations associated with Lyme borreliosis in Cali, Colombia, 20 serum samples from patients with dermatologic signs, one cerebrospinal fluid (CSF) sample from a patient with chronic neurologic and arthritic manifestations, and twelve serum samples from individuals without clinical signs associated with Lyme borreliosis were analyzed by IgG Western blot. The results were interpreted following the recommendations of the Centers for Diseases Control and Prevention (CDC) for IgG Western blots. Four samples fulfilled the CDC criteria: two serum specimens from patients with morphea (localized scleroderma), the CSF from the patient with neurologic and arthritic manifestations, and one of the controls. Interpretation of positive serology for Lyme disease in non-endemic countries must be cautious. However these results suggest that the putative "Lyme-like" disease may correlate with positivity on Western blots, thus raising the possibility that a spirochete genospecies distinct from B. burgdorferi sensu stricto, or a Borrelia species other than B. burgdorferi sensu lato is the causative agent. Future work will focus on a survey of the local tick and rodent population for evidence of spirochete species that could be incriminated as the etiologic agent.

Occupational allergy caused by carnation (Dianthus caryophyllus)

BACKGROUND

Occupational respiratory symptoms caused by decorative flowers are seldom reported in the literature. In our area a large portion of the population works in carnation (Dianthus caryophyllus) winter quarters, and many workers have symptoms of rhinitis and asthma related to exposition.

OBJECTIVE

The purposes of this study were to investigate whether the symptoms induced by carnation were IgE-mediated and to study the possible allergens involved.

METHODS

A total of 16 subjects employed in indoor carnation cultivation with symptoms during exposition time were studied along with 15 patients with allergic asthma who were not exposed to carnations and 15 healthy carnation workers used as control subjects. Skin prick tests with carnation extract and RASTs were performed. Protein bands were isolated by SDS-PAGE, and afterwards immunoblotting was performed to characterize the extract. Specific nasal provocation and nonspecific bronchial provocation tests were performed for all the asthmatic patients. Diurnal variation in peak expiratory flow was also measured.

RESULTS

Skin prick test responses with carnation extract were positive in 15 of the 16 patients and negative in all control subjects. Nasal provocation test responses with carnation extract were positive in 13 of 16 patients. A significant correlation was seen between RAST and nasal provocation results (P <.01). Immunoblotting of sera from 13 patients showed 2 major IgE-binding fractions of 34 and 35 kd in most of the patients, which could constitute the major allergen. Methacholine PD20 showed a variable degree of nonspecific bronchial hyperresponsiveness in all asthmatic subjects.

CONCLUSION

Data demonstrate the involvement of carnation in occupational allergy, mediated by an IgE-dependent mechanism.

Increase in alfalfa nodulation, nitrogen fixation, and plant growth by specific DNA amplification in Sinorhizobium meliloti

To improve symbiotic nitrogen fixation on alfalfa plants, Sinorhizobium meliloti strains containing different average copy numbers of a symbiotic DNA region were constructed by specific DNA amplification (SDA). A DNA fragment containing a regulatory gene (nodD1), the common nodulation genes (nodABC), and an operon essential for nitrogen fixation (nifN) from the nod regulon region of the symbiotic plasmid pSyma of S. meliloti was cloned into a plasmid unable to replicate in this organism. The plasmid then was integrated into the homologous DNA region of S. meliloti strains 41 and 1021, which resulted in a duplication of the symbiotic region. Sinorhizobium derivatives carrying further amplification were selected by growing the bacteria in increased concentrations of an antibiotic marker present in the integrated vector. Derivatives of strain 41 containing averages of 3 and 6 copies and a derivative of strain 1021 containing an average of 2.5 copies of the symbiotic region were obtained. In addition, the same region was introduced into both strains as a multicopy plasmid, yielding derivatives with an average of seven copies per cell. Nodulation, nitrogenase activity, plant nitrogen content, and plant growth were analyzed in alfalfa plants inoculated with the different strains. The copy number of the symbiotic region was critical in determining the plant phenotype. In the case of the strains with a moderate increase in copy number, symbiotic properties were improved significantly. The inoculation of alfalfa with these strains resulted in an enhancement of plant growth.

Assertiveness predicts threat and challenge reactions to potential stress among women

In this study assertiveness as a moderator of stress reactions among women was examined. Specifically, the experimenters examined how high and low assertive women cognitively appraised, affectively and physiologically responded to, and behaviorally coped with the stress of giving an impromptu speech. High assertive women appraised the speech stressor as challenging, whereas low assertive women appraised the stressor as threatening. High assertive women also had a challenge pattern of autonomic response during the task, compared with the threat response of low assertive women. Afterward, the high assertive women reported experiencing less stress and negative emotion and greater positive emotion than did the low assertive women. Overall, the high assertive women's stress-related reactions indicated challenge, whereas the low assertive women's reactions indicated threat (see J. Tomaka, J. Blascovich, R. M. Kelsey, & C. L. Leitten, 1993).

[Fungemia by Candida non albicans in patients with HIV infection]

OBJECTIVE

To analyse candidemia by Candida non albicans in adult HIV-infected patients from 1989 to August 1998.

PATIENTS AND METHODS

We retrospectively reviewed all HIV patients who presented at least one positive peripheral blood culture for Candida spp. Clinical, epidemiologic, immunologic and evolutive characteristics, and risk factors for candidemia were analysed.

RESULTS

During this period of time, 2,025 HIV-infected patients were diagnosed. Five of them developed candidemia by C. albicans and 6 by C. non albicans. These last ones were all men with mean age of 32.1 years old, and intravenous drug use was the risk factor for HIV in 5 of them; aids had previously been diagnosed in 4 patients and 3 had receipt imidazoles. None was neutropenic. Three cases were nosocomially acquired. Median CD4 cell count was 108.6 x 10(6)/l (3-366). Candida krusei was isolated in two intravenous drug users, Candida parapsilosis in two other patients and Candida glabrata and Candida tropicalis in one of the other two cases each. We treated 2 patients with amphotericin B and 2 with fluconazole. One patient died.

CONCLUSIONS

Candidemia is not frequent in HIV-infected patients. Candidemia by C. non albicans in HIV-infected patients presents similar characteristics as in other immunodepressed patients and it is fundamentally associated with previous use of imidazoles, nosocomial acquisition and late-stage aids. It is noteworthy that C. krusei was isolated in two intravenous drug users.

Identification of a 36-kDa olive-pollen allergen by in vitro and in vivo studies

BACKGROUND

Ole e 1 has been considered the major allergen of olive (Olea europaea) pollen. Some other relevant allergens (Ole e 2, 3, 4, and 6) have been recently described. This work aimed to study the IgE-binding frequency of a 36-kDa protein from O. europaea pollen in a large population of olive-allergic patients, its allergenic reactivity in vivo, and its presence in olive pollens of different origin, as well as in other relevant allergenic pollens.

METHODS

Identification of IgE-binding components from O. europaea pollen extracts was elucidated by inhibition of SDS-PAGE immunoblotting using recombinant profilin (Ole e 2) and Ole e 1 molecules. The IgE-binding frequency of the 36-kDa protein was estimated by Western blot in a sample of 120 sera from olive-allergic patients. The cutaneous test with the 36-kDa protein was performed by intradermoreaction in allergic patients and control subjects.

RESULTS

Exactly 83% of the sera from O. europaea-allergic patients recognized a protein with an apparent molecular weight of 36 kDa, under reducing conditions. It was detected by sera from monosensitized and polysensitized patients, showing a higher IgE frequency than the major allergen Ole e 1 (59%) and the minor profilin (Ole e 2) allergen (27%). Similar reactivity rates (79%) was found by intradermal test. Extracts from olive pollens collected in California presented a much higher amount (around 16-fold on average) of the 36-kDa protein than those from pollens of Spanish origin. The presence of similar allergens was detected only in closely related species (Syringa, Fraxinus, Ligustrum), and not in other common allergenic pollens.

CONCLUSIONS

The 36-kDa protein constitutes a major allergen for olive-sensitized patients, but it is not equally represented in O. europaea pollens of different origins.

Serum sickness-like syndrome due to mosquito bite

Local inflammatory reactions at the site of a mosquito bite are frequent. Immediate systemic reactions have occasionally been reported. The first case of a patient with relapsing episodes of a serum sickness-like syndrome following mosquito bites is reported herein. A 62-year-old patient came to the emergency room complaining of sudden malaise, chills, fever, headache, cervical lymph node enlargement, arthromyalgia, generalized purpura and leukopenia 6 h after a mosquito bite. He had experienced multiple similar episodes in the last 20 years, also following mosquito bites. Infectious and autoimmune diseases were ruled out. Serum IgE was 9,102 kU/l. Prick test of whole-body Culex pipiens extract was positive. Specific IgE to Aedes communis was 2.25 kU/l. SDS-PAGE immunoblotting of the patient's serum with whole-body C. pipiens extract revealed 43 and 17 kDa IgG-binding proteins and 22 and 17 kDa IgE-binding proteins, neither of which were found with control sera. Skin biopsy was consistent with leukocytoclastic vasculitis. The presence of both mosquito-specific IgE and IgG in the patient's serum suggest a possible cooperative immune response leading to clinical manifestations of serum sickness.

Enzymatic analyses of house dust mite extracts from Dermatophagoides pteronyssinus and Dermatophagoides farinae (Acari: Pyroglyphidae) during different phases of culture growth

The majority of clinically important allergens of Dermatophagoides pteronyssinus (Trouessart, 1897) and Dermatophagoides farinae Hughes, 1961 present enzymatic activity. The allergenic enzymes described include cysteine proteases in group 1 allergens, trypsins in group 3, amylases in group 4, and chymotrypsins in group 6. Apart from these, other possibly allergenic enzymes also have been identified. Therefore, enzymatic profiles were studied during the 3 growth periods of the mite population--latency phase, exponential growth phase, and death phase. The activity of 19 different enzymes was analyzed by means of the Api Zym system, a method that has been used to study both mite extracts and other allergenic materials. Our study has demonstrated that the extracts contain a large variety of enzymes. It has been observed that enzymatic activity is caused exclusively by mites because the control carried out on the culture medium was negative for all the enzymes studied. Generally, the levels of diverse enzymatic activity increased with the growth of the culture, and decreased later, in both species. However, proteases are the exception; they maintain a high level of activity during the death phase of the cultured mites. The ratio between trypsin and chymotrypsin activity can be used as an excellent tool for quality control parameters during obtention of allergenic mite extracts.

Molecular characterization of American cockroach tropomyosin (Periplaneta americana allergen 7), a cross-reactive allergen

Inhalation of allergens produced by the American cockroach (Periplaneta americana) induces IgE Ab production and the development of asthma in genetically predisposed individuals. The cloning and expression in Escherichia coli of P. americana tropomyosin allergen have been achieved. The protein shares high homology with other arthropod tropomyosins (80% identity) but less homology with vertebrate ones (50% identity). The recombinant allergen was produced in E. coli as a nonfusion protein with a yield of 9 mg/l of bacterial culture. Both natural and recombinant tropomyosins were purified by isoelectric precipitation. P. americana allergen 1 (Per a 1) and Per a 7 (tropomyosin) are to date the only cross-reacting allergens found in cockroaches. ELISA and Western blot inhibition experiments, using natural and recombinant purified tropomyosins from shrimp and cockroach, showed that tropomyosin induced cross-reactivity of IgE from patients allergic to these allergens, suggesting that this molecule could be a common allergen among invertebrates.