Optimization of enterocin P production by batch fermentation of Enterococcus faecium P13 at constant pH

The influence of pH on growth, enterocin P production and glucose consumption by Enterococcus faecium P13 was studied during anaerobic batch fermentation in MRS broth at 32 degrees C in a fermentor. Growth and glucose consumption were maximal at pH 7.0. Enterocin P production displayed primary metabolite kinetics and was strongly dependent on pH. A maximum antimicrobial activity of 1,949 bacteriocin units (BU) ml(-1) was obtained at pH 6.0, which represented a four-fold increase compared with the antimicrobial activity obtained without pH regulation. The pH exerted a marked effect on the decrease in bacteriocin activity, with the decrease being maximal at pH 7.0. In this report, we propose models for the growth of E. faecium P13 as well as enterocin P production and inactivation. Enterocin P production decreased when potentially stress-inducing compounds (NaCl or ethanol) were included in the growth medium.

African swine fever virus structural protein pE120R is essential for virus transport from assembly sites to plasma membrane but not for infectivity

This report examines the role of African swine fever virus (ASFV) structural protein pE120R in virus replication. Immunoelectron microscopy revealed that protein pE120R localizes at the surface of the intracellular virions. Consistent with this, coimmunoprecipitation assays showed that protein pE120R binds to the major capsid protein p72. Moreover, it was found that, in cells infected with an ASFV recombinant that inducibly expresses protein p72, the incorporation of pE120R into the virus particle is dependent on p72 expression. Protein pE120R was also studied using an ASFV recombinant in which E120R gene expression is regulated by the Escherichia coli lac repressor-operator system. In the absence of inducer, pE120R expression was reduced about 100-fold compared to that obtained with the parental virus or the recombinant virus grown under permissive conditions. One-step virus growth curves showed that, under conditions that repress pE120R expression, the titer of intracellular progeny was similar to the total virus yield obtained under permissive conditions, whereas the extracellular virus yield was about 100-fold lower than in control infections. Immunofluorescence and electron microscopy demonstrated that, under restrictive conditions, intracellular mature virions are properly assembled but remain confined to the replication areas. Altogether, these results indicate that pE120R is necessary for virus dissemination but not for virus infectivity. The data also suggest that protein pE120R might be involved in the microtubule-mediated transport of ASFV particles from the viral factories to the plasma membrane.

Recurrent papillary thyroid cancer: analysis of prognostic factors including the histological variant

OBJECTIVE

To analyse the factors that influence the development of recurrent papillary thyroid carcinoma, including the histological variant.

DESIGN

Retrospective study.

SETTING

Teaching hospital, Spain.

SUBJECTS

200 patients who had papillary thyroid cancers resected between 1970 and 1995.

MAIN OUTCOME MEASURES

Prognostic factors and disease-free interval assessed by univariate and multivariate analysis.

RESULTS

All patients were followed up for a mean of 9 years (range 4-29). 54 patients presented with recurrent disease (27%) of whom 19 (35%) died of their disease. 5-year, 10-year, and 15-year survival for those with recurrent disease were 75%, 68%, and 60%, respectively. The corresponding figures for the whole series were 93%, 90%, and 84%. The significant variables on multivariate analysis were completeness of resection (p = 0.002), extrathyroid involvement (p < 0.002), presence of lymph node metastases (p = 0.002), and histological variant of the carcinoma (P < 0.001).

CONCLUSION

Using these risk factors it is possible to draw up a prognostic index and classify patients as being at low, medium, or high risk of recurrence.

First Report of Basal Rot of Leek Caused by Fusarium culmorum in Spain

A severe basal rot of leek (Allium porrum L.) was first observed in 1996 in Sueca (Valencia) eastern Spain, and again from 1998 to 2000 in several fields in Haro (La Rioja) northern Spain, where the disease caused significant economic losses. Leeks were stunted, wilted, and had water-soaked tissues with a characteristic reddish purple discoloration at the base of the stem. Affected plants could be pulled up easily because of rotting of the basal plate and root system. Similar symptoms were also observed on seedlings 2 to 3 weeks after transplanting. Isolations from symptomatic stems and roots onto potato dextrose agar (PDA) supplemented with 0.5 mg/ml of streptomycin sulfate (PDAS) consistently yielded a Fusarium sp. Isolates were transferred to potato sucrose agar (PSA) and synthetic low nutrient agar (SNA) and incubated at 25°C for 10 days with a 12-h photoperiod. The isolates were identified as Fusarium culmorum (Wm. G. Sm.) Sacc. based on colony morphology on PSA and phialide and conidial morphology on SNA. This disease has been described on garlic (1), but there are few reports about its incidence on leek (2). Pathogenicity tests were conducted on leek cvs. Alora, Axel, Casado, Goliath, and Varea using five isolates of F. culmorum from different locations. Ninety-day-old seedlings were inoculated by introducing a spore suspension to obtain a soil infested with the fungus at 10⁴ colony-forming units (CFU)/g of potting mix (a sterilized mixture of equal portions [v/v] of soil, sand, and peat moss). Plants were maintained in a greenhouse at 20 to 30°C. Within 45 to 70 days after inoculation, symptoms developed that were similar to those observed in the field. The fungus was reisolated from affected plants, completing Koch's postulates. All isolates were pathogenic, and all leek cvs. were highly susceptible to the pathogen. To our knowledge, this is the first report of F. culmorum affecting leek in Spain. References: (1) F. J. Crowe et al. Phytopathology 76:1094, 1986. (2) G. Tamietti and A. Garibaldi. Riv. di Patol. Veg. IV. 13:69, 1977.

Familial papillary carcinoma of the thyroid: report of three families

OBJECTIVE

To report our experience of the clinical characteristics, treatment and outcome of familial papillary carcinoma.

DESIGN

Descriptive study.

SETTING

Tertiary referral centre, Spain.

PATIENTS

Eight patients from three families.

INTERVENTIONS

Treatment for familial papillary carcinoma of thyroid.

MAIN OUTCOME MEASURES

Age, sex, reason for consultation, preoperative investigation, indication for operation and type, variety of papillary carcinoma and characteristics (size, adenopathies, multicentricity and bilaterality), treatment with 131I, and outcome.

RESULTS

The mean (SD) age was 46 (14) years, and seven were women. In all but one patient, who was admitted for hypercalcaemia and operated on for primary hyperparathyroidism, cervical palpation and ultrasound showed a thyroid nodule. Needle aspiration suggested papillary carcinoma in 6/7, who were all treated by total thyroidectomy. Four patients with enlarged nodes also had bilateral neck disection. All the papillary carcinomas were well-differentiated, mean (SD) diameter was 1.5 (1) cm and in four were microcarcinomas. Three patients presented with invaded nodes. They were all treated postoperatively with 131I, except the patient with hyperparathyroidism who had a microcarcinoma of 0.5 cm. After a median (range) follow-up of 1 (0, 6-7) years the patients are well, except one had a high thyroglobulin concentration seven years later; however clinical exploration and morphological screening were within normal limits and he was treated with 131I 5.6 x 10(9) Bq.

CONCLUSIONS

About a third of familial papillary carcinomas of the thyroid have lymph node involvement at the time of diagnosis, and have a relatively good prognosis if treated in accordance with the stage of the disease.

Anti-proliferative effect of two lactic acid bacteria strains of human origin on the growth of a myeloma cell line

AIMS

Twenty lactic acid bacteria strains were isolated from human faeces and tested by MTT assay for stimulation or inhibition of the proliferation of Vero and myeloma cells.

METHODS AND RESULTS

None of the strains significantly affected the proliferation of Vero cells. However, two isolates (HN1 and HA8) showed a strong inhibition of myeloma cell proliferation (16.7 and 5.0%, respectively) by MTT assay.

CONCLUSION

Both strains have an anti-proliferative effect on a tumoral cell line.

SIGNIFICANCE AND IMPACT OF THE STUDY

The beneficial effect of LAB cancer therapy has been linked to their ability for immunomodulation.

Extrathyroid spread in papillary carcinoma of the thyroid: clinicopathological and prognostic study

INTRODUCTION

The extrathyroid spread (ETS) is one of the risk factors that influence mortality and recurrence in patients with papillary carcinoma of the thyroid (PCT). The aim of this study is to analyze the clinical and histologic features and follow-up of a series of patients with ETS undergoing surgery for PCT and to identify patients with a greater risk of presenting with ETS.

MATERIAL AND METHODS

Retrospective study of a series of 200 patients undergoing surgery for PCT, of whom 47 (23.5%) presented with ETS. The clinical and histologic features and follow-up of the patients with ETS were compared with those without ETS using the Pearson chi(2) test. We used a logistics regression model to perform a multivariant analysis for ETS. The survival and disease-free interval rates were calculated using the Kaplan-Meier method.

RESULTS

ETS is most associated with patients over 50 years of age, with tumors over 4 cm that are not encapsulated, with lymph node metastasis, and with certain PCT histologic subtypes after the multivariant analysis. The overall rate of recurrence and mortality in patients with ETS was much higher than in patients without ETS.

CONCLUSIONS

PCT patients with ETS have a greater risk of tumor-related recurrence and mortality than patients without ETS. There are patients with certain clinical and histologic features who have a greater risk of presenting with ETS.

Cavernous hemangioma of the thyroid

Most current vascular alterations of the thyroid are connected with the organization of a thyroid hematoma after fine-needle aspiration (FNA). Cavernous hemangioma is a benign congenital vascular malformation that occasionally affects the thyroid. This article presents two cases of this rare thyroid pathology unrelated to FNA.

Structural and functional analysis of mutations in alkaptonuria

Alkaptonuria (AKU), the prototypic inborn error of metabolism, was the first human disease to be interpreted as a Mendelian trait by Garrod and Bateson at the beginning of last century. AKU results from impaired function of homogentisate dioxygenase (HGO), an enzyme required for the catabolism of phenylalanine and tyrosine. With the novel 7 AKU and 22 fungal mutations reported here, a total of 84 mutations impairing this enzyme have been found in the HGO gene from humans and model organisms. Forty-three of these mutations result in single amino acid substitutions. This mutational information is analysed here in the context of the HGO structure and function using kinetic assays performed using purified AKU mutant enzymes and the crystal structure of human HGO. HGO is a topologically complex structure which assembles as a functional hexamer arranged as a dimer of trimers. We show how the intricate pattern of intra- and inter-subunit interactions and the extensive surfaces required for subunit folding and association of this oligomeric enzyme can be inactivated at multiple levels by single-residue substitutions. This explains, in part, the predominance of missense mutations (67%) in AKU.

Sulfite-reducing clostridia in the sediment of a high mountain lake (Laguna Grande, Gredos, Spain) as indicators of fecal pollution

We studied the vertical distribution of sulfite-reducing clostridia in the sediment of a Spanish high-mountain lagoon (Laguna Grande de Gredos, central Spain), with optimal sediment characteristics (temperature < 20 degrees C) to maintain spores without growing. This allowed us to assess the original numbers of sulfite-reducing clostridia endospores settled, without postdepositional growing. Sulfite-reducing clostridia are normal inhabitants of the intestinal microbiota of humans and other mammals. These microorganisms may form endospores, which allow the bacteria to survive in almost any habitat, either terrestrial or aquatic, waiting for favorable conditions for growth. Sulfite-reducing clostridia could be suitable indicators of past human pollution because they have a great longevity in natural habitats and they cannot multiply at temperatures below 20 degrees C or in the presence of O2. We found a great increase in the numbers of clostridia (expressed as colony-forming units per gram [CFU/g] of dry weight of sediment) since the 1970s, which reflects the rise of human pressure caused by the practice of outdoor activities. Clostridia CFU/g rose dramatically after the faulty operation of the depuration system of a mountain refuge built close to the lagoon. We compared the vertical distribution of clostridia CFU/g from Laguna Grande sediments with those from a neighbor lagoon (Laguna Cimera), which showed less tourist pressure and no direct disposal of sewage. Finally, we agree with the usefulness of the numbers of sulfite-reducing clostridia as indicators of past pollution.

[Treatment of retroperitoneal sarcoma]

AIM

To evaluate the results of treatment of retroperitoneal sarcomas.

PATIENTS AND METHODS

We evaluated clinical, diagnostic, surgical and histological parameters as well as adjuvant therapy and evolution in 15 patients with retroperitoneal sarcoma.

RESULTS

All patients presented abdominal tumors at diagnosis. Imaging revealed retroperitoneal origin. Complete surgical resection was carried out in seven patients (47%), reduction in size of tumor mass in five (33%) and exploratory laparotomy in three (20%). Histological analysis revealed 12 liposarcoma (80%), two leiomyosarcoma (13%) and one fibrosarcoma. Adjuvant therapy was given to two patients. Of the patients who underwent complete surgical resection, four survived without relapse (1, 2, 5 and 5 years respectively). With the other treatments, there were no survivals at 2 years. Adjuvant therapy did not influence survival.

CONCLUSIONS

Retroperitoneal sarcoma is diagnosed late. Prognosis is poor due to tumor relapse and only complete surgical removal produces a "cure".

Botulinum treatment of infantile esotropia with abduction nystagmus

PURPOSE

To examine the effect of botulinum toxin type A (BTA) on the final correction of esotropia, A and V patterns, overaction of the oblique muscles, and dissociated vertical deviation (DVD) in infantile esotropia with nystagmus in abduction.

METHODS

This retrospective study examined 54 patients treated with simultaneous bilateral medial injection of BTA. Subjects were divided into two groups: group 1 (first injection <18 months of age) and group 2 (first injection >18 months of age).

RESULTS

Pre-BTA, group 1 patients had an angle of esotropia noticeably higher and fewer A patterns than group 2 patients. Post-BTA, group 2 received significantly fewer injections of BTA than group 1. The magnitude of the A patterns improved. Prior frequency of DVD increased significantly in group 1 (100%): 79% of DVD was decompensated compared with 47% in group 2. Overall success was obtained in 14% and 58% of groups 1 and 2, respectively.

CONCLUSION

We do not support BTA treatment in infantile esotropia with nystagmus in abduction prior to age 18 months. After 18 months, the horizontal results are excellent and neither the incidence nor the degree of previous DVD are decompensated, resulting in high success rates for overall deviation and improving anisotropy in A.

Patient satisfaction with a home televisiting service based on interactive television over a cable network

Experience shows that high-quality audiovisual contact between remote health carers and patients facilitates a telemedicine service. However, the lack of broadband communication to the home usually prevents domestic televisiting. Deployment of cable networks in Spain has allowed the implementation of a home televisiting service designed for patients with chronic diseases. In a trial, 15 patients received televisits by three specialists and three nurses from the Severo Ochoa Hospital in Madrid. Five patients suffered from chronic pain, five were from the nephrology unit and five had been treated at the intensive-care unit after acute myocardial infarction. Each patient participated in three televisiting sessions, two provided by a specialist and the other by a nurse. The average length of a televisit was 12 min (range 5-21 min). The patients expressed their satisfaction with the service.

Biochemical and genetic evidence of enterocin P production by two Enterococcus faecium-like strains isolated from fermented sausages

Two bacteriocin-producing Enterococcus faecium-like strains were independently isolated from fermented sausages. Bacteriocins were purified to homogeneity by ammonium sulfate precipitation, gel filtration, cationic exchange, hydrophobic interaction, and reverse-phase liquid chromatography. Two peptide inhibitory fractions were purified from each strain, denominated A and B for E. faecium AA13, and C and D for E. faecium G16. Fraction B was blocked for amino acid sequencing by Edman degradation, while the amino acid sequences obtained from peptides A, C, and D contained the YGNGV consensus motif in positions 5 to 9, and the ATRS sequence in positions 1 to 4. By use of PCR techniques and nucleotide sequencing, the structural gene of enterocin P was found both in E. faecium AA13 and E. faecium G16. Metabolic and genetic features of the two strains suggest that they are slightly different, they may produce more than one bacteriocin, and both produce enterocin P.

Ex-vivo expansion and maturation of CD34-positive hematopoietic progenitors optimization of culture conditions

The aim of this study was to look for an ex vivo culture system for clinical application. We evaluated the ex vivo expansion of peripheral blood CD34+ cells in gas-permeable bags and whether or not an exogenous protein source would be required in these kind of cultures. We also evaluated maturation of the cells during culture. Cells were cultured for 15 days in medium supplemented with SCF, G-CSF, IL3 and IL6. The bags supported the expansion of hematopoietic cells in a similar manner to small scale flasks system: (a) the expansion means of total nucleated cells on day +5 were 12.5-fold for bag versus 5-fold for flask, on day +10 were 44.12-fold for bag versus 41-fold for flask and on day +15 were 67.7-fold for bag versus 84.2-fold for flask, (b) the peak values of CFU-GM were reached on day +10 (9.2-fold for bag vs. 12-fold for flask), and (c) maximal expansion of CD15+/CD11b- population occurred on day +10 (517.5-fold for bag vs. 2959.2-fold for flask). So, we did not find any advantages by culturing further than day +10. We subsequently investigated the use of serum-free medium. The study showed better results when we used medium supplemented with autologous plasma versus serum-free system. In summary, these data described a strategy of culture clinically feasible and safe, using gas-permeable bags, and the kinetics and differentiation of neutrophils and neutrophil precursors from selected CD34+ cells in liquid cultures. Ex vivo expansion of this population might result in earlier engraftment as compared with that for selected stem cells alone.

Using cable television networks for interactive home telemedicine services

Most recent cable television network infrastructures can be used to deliver broadband interactive telemedicine services to the home. These facilities allow the provision of social and health services like medical televisiting for elderly, disabled and chronically ill patients; health tele-education; and teleconsultation on demand. Large numbers of patients could benefit from these services. There is also the increasing European tendency to offer customized home-care services. These applications are being developed and validated by a pilot project in Madrid as part of the ATTRACT project of the European Commission. The long-term aim is to develop broadband applications on a large scale to support low-cost interactive home telemedicine services for both patients and institutions.

Enhanced production of pediocin PA-1 and coproduction of nisin and pediocin PA-1 by Lactococcus lactis

The production and secretion of class II bacteriocins share a number of features that allow the interchange of genetic determinants between certain members of this group of antimicrobial peptides. Lactococcus lactis IL1403 encodes translocatory functions able to recognize and mediate secretion of lactococcin A. The ability of this strain to also produce the pediococcal bacteriocin pediocin PA-1, has been demonstrated previously by the introduction of a chimeric gene, composed of sequences encoding the leader of lactococcin A and the mature part of pediocin PA-1 (N. Horn, M. I. Martínez, J. M. Martínez, P. E. Hernández, M. J. Gasson, J. M. Rodríguez, and H. M. Dodd, Appl. Environ. Microbiol. 64:818-823, 1998). This heterologous expression system has been developed further with the introduction of the lactococcin A-dedicated translocatory function genes, lcnC and lcnD, and their effect on bacteriocin yields in various lactococcal hosts was assessed. The copy number of lcnC and lcnD influenced production levels, as did the particular strain employed as host. Highest yields were achieved with L. lactis IL1403, which generated pediocin PA-1 at a level similar to that for the parental strain, Pediococcus acidilactici 347, representing a significant improvement over previous systems. The genetic determinants required for production of pediocin PA-1 were introduced into the nisin-producing strain L. lactis FI5876, where both pediocin PA-1 and nisin A were simultaneously produced. The implications of coproduction of these two industrially relevant antimicrobial agents by a food-grade organism are discussed.

Antibodies to a synthetic 1-9-N-terminal amino acid fragment of mature pediocin PA-1: sensitivity and specificity for pediocin PA-1 and cross-reactivity against Class IIa bacteriocins

Polyclonal antibodies specific for pediocin PA-1 (PedA1) were generated by immunization of rabbits with a chemically synthesized 1-9-N-terminal amino acid fragment of this bacteriocin (PH1) conjugated to the carrier protein keyhole limpet haemocyanin (KLH). The PH1 fragment holds a highly conserved amino acid sequence with closely related Class IIa bacteriocins. The sensitivity and specificity of the PH1-KLH-generated rabbit polyclonal antibodies were evaluated by the development of various ELISAs, such as a non-competitive indirect ELISA (NCI-ELISA), a competitive indirect ELISA (CI-ELISA), a competitive direct ELISA (CD-ELISA) and a sandwich ELISA (S-ELISA), and by protein slot-blotting and Western blotting. NCI- and CI-ELISA were valuable for detecting the existence of PedA1-specific antibodies in the sera of immunized rabbits. The limit of detection of PedA1 in MRS medium was found to be 0.5 microg ml(-1) in NCI-ELISA, while CI-ELISA on plates coated with purified PedA1 increased the affinity of the PH1-KLH-generated antibodies for PedA1; the limit of detection of PedA1 was less than 0.01 microg ml(-1) and 50% binding inhibition was achieved with 0.1 microg PedA1 ml(-1). Similarly, the limits of detection of PedA1 in MRS medium were found to be 5 microg ml(-1) by protein slot-blotting and 0.01 microg ml(-1) by Western blotting. Most importantly, PH1-KLH-generated polyclonal antibodies detected the presence of PedA1 in the supernatants of the producing strains of Pediococcus acidilactici 347, Z102, A172, X13 and P20, with no reactivity or negligible immunoreactivity with the supernatants of other lactic acid bacteria producing or not producing closely related or different bacteriocins. The approaches taken for the selection of the bacteriocin peptide fragment, the generation of antibodies and the development of immunoassays could prove useful for the generation and evaluation of antibodies of adequate specificity for other bacteriocins of interest in the food industry.