Characteristics and outcomes of the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB)

INTRODUCTION AND OBJECTIVES

Bicuspid aortic valve (BAV) disorder is the most common congenital heart disease. The aim of this study was to describe the characteristics of 0- to 18-year olds with BAV in a population-based registry.

METHODS

Data from all pediatric patients were obtained from the Spanish registry for pediatric patients with bicuspid aortic valve (REVAB) (< 18 years). For data analysis, patients with BAV were divided into 2 groups by their features: isolated BAV and BAV with associated congenital heart disease.

RESULTS

We included 1681 patients from 33 hospitals. Males accounted for 69.6% (n = 1158). Valve morphology was horizontal in 63.4% (n = 1012) and pure (Sievers type 0) in 28.4% (n=469). Isolated BAV was present in 63.7% (n=1060), and concomitant left-sided obstructive lesions in 23.4% (n=390). Interventions were required in 8.6% (n=145).

CONCLUSION

These data represent the first large, population-based description of the clinical presentations and outcomes of patients enrolled in the Spanish registry for pediatric patients with bicuspid aortic valve.

Targeting oncogenic functions of miR-301a in head and neck squamous cell carcinoma by PI3K/PTEN and MEK/ERK pathways

Treatment of head and neck squamous cell carcinomas (HNSCC), the sixth most frequent cancer worldwide, remains challenging. miRNA dysregulation is closely linked to tumorigenesis and tumor progression, thus emerging as suitable targets for cancer treatment. Transcriptomic analysis of TCGA HNSCC dataset revealed that miR-301a expression levels significantly increased in primary tumors, as compared to patient-matched normal tissue. This prompted us to investigate its pathobiological role and potential as new therapeutic target using different preclinical HNSCC models. miR-301a overexpression in HNSCC-derived cell lines led to enhanced proliferation and invasion, whereas miR-301 inhibition reduced these effects. In vivo validation was performed using an orthotopic mouse model. Results concordantly showed that the mitotic counts, the percentage of infiltration depth and Ki67 proliferative index were significantly augmented in the subgroup of mice harboring miR-301a-overexpressing tumors. Further mechanistic characterization revealed PI3K/PTEN/AKT and MEK/ERK pathways as central signaling nodes responsible for mediating the oncogenic activity of miR-301a observed in HNSCC cells. Notably, pharmacological disruption of PI3K and ERK signals with BYL-719 and PD98059, respectively, was effective to completely revert/abolish miR-301a-promoted tumor cell growth and invasion. Altogether, these findings demonstrate that miR-301a dysregulation plays an oncogenic role in HNSCC, thus emerging as a candidate therapeutic target for this disease. Importantly, available PI3K and ERK inhibitors emerge as promising anti-tumor agents to effectively target miR-301a-mediated signal circuit hampering growth-promoting and pro-invasive functions.

The Impact of Periventricular Leukoaraiosis in Post-stroke Oropharyngeal Dysphagia: A Swallowing Biomechanics and MRI-Based Study

Oropharyngeal dysphagia is a highly prevalent post-stroke complication commonly associated with topographically specific gray-matter damage. In contrast, the role of damage to the extensive white matter brain network (leukoaraiosis) in post-stroke oropharyngeal dysphagia has not yet been clarified. We aim to assess the role of leukoaraiosis in post-stroke oropharyngeal dysphagia. We designed a cross-sectional study and retrospectively collected from our database patients with dysphagia affected by a recent stroke and on whom both a brain 1.5 T-MRI and a videofluoroscopy had been performed. Leukoaraiosis was assessed in brainstem and in cerebral regions (periventricular or deep) with Fazekas scale. Penetration-Aspiration-Scale and time to laryngeal vestibule closure and to upper esophageal sphincter opening were analyzed. Study population (n = 121; 57% men, 75.5 ± 9.4y) presented mostly supratentorial ischemic PACI-type strokes. Of the patients, 86% had unsafe swallows (PAS = 3.97 ± 2.04); 94.2% had cerebral leukoaraiosis (Fazekas = 3.36 ± 1.7) and 42.1% had brainstem-leukoaraiosis, hypertension being the main risk factor. We found both significant positive associations between degree of periventricular-leukoaraiosis and total-leukoaraiosis and presence of risk of aspirations (p = 0.016 and p = 0.023, respectively); and a correlation between periventricular-leukoaraiosis and PAS scale severity (r = 0.179, p = 0.049). No correlations/associations were found between stroke volume and dysphagia in this study. Our study supports a role for leukoaraiosis in the pathophysiology of dysphagia. Stroke is associated with chronic short-connection/circuit injury and damage to periventricular white matter long connections is a relevant neuro-pathophysiological mechanism contributing to impaired safety of swallow in post-stroke oropharyngeal dysphagia patients.

Spiny keratoderma

Spiny keratoderma is a rare entity characterized by filiform keratotic lesions on palms and soles. Although there are some inherited cases the majority are acquired. This last variant can be idiopathic or associated with neoplasms and chronic systemic diseases. We report a new case of spiny keratoderma associated with endometrial carcinoma.

Cord Blood Biomarkers of Cardiac Dysfunction and Damage in Term Growth-Restricted Fetuses Classified by Severity Criteria

OBJECTIVE

To assess cardiovascular function and damage in term small-for-gestational-age (SGA) and intrauterine growth-restricted (IUGR) fetuses by echocardiography and biomarkers in cord blood.

METHODS

This was a cohort study including 60 normal fetuses and 47 term small fetuses subclassified as small for gestational age (SGA) with estimated fetal weight (EFW) between the 3rd and 9th centiles and normal fetoplacental Doppler (n = 14) or intrauterine growth restriction (IUGR, n = 33) if EFW <3rd centile or EFW <10th centile together with cerebroplacental ratio <5th and/or mean uterine artery pulsatility index >95th centile. Fetal echocardiography included left myocardial performance index (MPI) and annular plane systolic excursion. Fetal B-type natriuretic peptide (BNP), troponin-I, heart-type fatty acid-binding proteins (H-FABP), and homocysteine concentrations were measured in cord blood collected at delivery.

RESULTS

Both SGA and IUGR cases presented echocardiographic signs of systolic and diastolic dysfunction with increased MPI (mean controls 0.43 [SD 0.12], SGA 0.47 [0.03], and IUGR 0.57 [0.08], p < 0.01) and decreased mitral annular plane systolic excursion (controls 6.0 mm [1.0], SGA 5.5 mm [0.6], and IUGR 4.9 mm [0.8], p = 0 01). IUGR fetuses presented increased levels of cord blood BNP (controls 17.2 pg/mL [11.5], SGA 22.4 pg/mL [10.7], and IUGR 31.2 pg/mL [26.8], p < 0.01). Troponin I was increased in both SGA and IUGR cases (controls 0.004 ng/mL [0.007], SGA 0.012 ng/mL [0.02], and IUGR 0.018 ng/mL [0.05], p < 0.01). H-FABP and homocysteine showed similar values among groups.

CONCLUSIONS

Cardiac dysfunction and cell damage is a common feature of term SGA and IUGR fetuses despite of the severity criteria for perinatal outcome. Further research is needed to evaluate the potential long-term consequences on their cardiovascular system.

In-vitro development of an effective treatment for Acanthamoeba keratitis

The aim of this study was to develop an in-vitro topical treatment for Acanthamoeba keratitis (AK) effective against cysts and trophozoites. Qualitative assays were performed with voriconazole, chlorhexidine, propamidine, cellulase, tobramycin, ciprofloxacin and paromomycin as monotherapy and various combinations. Riboflavin with ultraviolet-A (R + UV-A) as monotherapy or combined with voriconazole and moxifloxacin was also tested. Quantitative assays to assess cyst viability after treatment were performed for the chemicals that showed the highest activity in the qualitative assays. Paromomycin and propamidine did not show antiamoebic activity. Regardless of the total dose, no amoebicidal effect was observed for R + UV-A. Tobramycin, ciprofloxacin, voriconazole, chlorhexidine and cellulase were selected for quantitative assays because they appeared to cause greater damage to the structure of amoebae. Chlorhexidine and ciprofloxacin were the most active against Acanthamoeba spp. as monotherapy. Among the combinations evaluated, ciprofloxacin-voriconazole-chlorhexidine showed the greatest amoebicidal activity, with severe damage of the cellular membrane and an important decrease in cell concentration. In summary, ciprofloxacin as monotherapy and in combination with voriconazole and chlorhexidine has been classified as promising treatment. Additional in-vivo studies in animal models and clinical trials in patients with AK should be considered to confirm the efficacy of ciprofloxacin.

Fetal cardiac function in late-onset intrauterine growth restriction vs small-for-gestational age, as defined by estimated fetal weight, cerebroplacental ratio and uterine artery Doppler

OBJECTIVE

Among late-onset small fetuses, a combination of estimated fetal weight (EFW), cerebroplacental ratio (CPR) and mean uterine artery (UtA) pulsatility index (PI) can predict a subgroup of fetuses with poor perinatal outcome; however, the association of these criteria with fetal cardiac structure and function is unknown. Our aim was to determine the presence and severity of signs indicating cardiac dysfunction in small fetuses, classified as intrauterine growth-restricted (IUGR) or small-for-gestational age (SGA), according to EFW, CPR and UtA-PI.

METHODS

A cohort of 209 late-onset small fetuses that were delivered > 34 weeks of gestation was divided in two categories: SGA (n = 59) if EFW was between the 3(rd) and 9(th) centiles with normal CPR and UtA-PI; and IUGR (n = 150) if EFW was < 3(rd) centile, or < 10(th) centile with a CPR < 5(th) centile and/or UtA-PI > 95(th) centile. The small population was compared with 150 appropriately grown fetuses (controls). Fetal cardiac morphometry and function were assessed by echocardiography using two-dimensional M-mode, conventional and tissue Doppler.

RESULTS

Compared with controls, both IUGR and SGA fetuses showed larger and more globular hearts (mean left sphericity index ± SD: controls, 1.8 ± 0.3; SGA, 1.5 ± 0.2; and IUGR, 1.6 ± 0.3; P < 0.01) and showed signs of systolic and diastolic dysfunction, including decreased tricuspid annular plane systolic excursion (mean ± SD: controls, 8.2 ± 1.1; SGA, 7.4 ± 1.2; and IUGR, 6.9 ± 1.1; P < 0.001) and increased left myocardial performance index (mean ± SD: controls, 0.45 ± 0.14; SGA, 0.51 ± 0.08; and IUGR, 0.57 ± 0.1; P < 0.001).

CONCLUSIONS

Despite a perinatal outcome comparable to that of normal fetuses, the population of so-defined SGA fetuses showed signs of prenatal cardiac dysfunction. This supports the concept that at least a proportion of them are not 'constitutionally small' and that further research is needed.

Identifying endosymbiont bacteria associated with free-living amoebae

The association between free-living amoebae and pathogenic bacteria is an issue that has gained great importance due to the environmental and health consequences that it implies. In this paper, we analyse the techniques to follow an epidemiological study to identify associations between genera, species, genotypes and subgenotypes of amoebae with pathogenic bacteria, analysing their evolution and considering their usefulness. In this sense, we highlight the combination of microscopic and molecular techniques as the most appropriate way to obtain fully reliable results as well as the need to achieve the standardization of these techniques to allow the comparison of both environmental and clinical results.

A new pentaplex-nested PCR to detect five pathogenic bacteria in free living amoebae

Changes in water use and anthropogenic activity have major impacts on the quality of natural aquatic ecosystems, water distribution and wastewater plants. One of the main problems is the presence of some pathogenic microorganisms that are resistant to disinfection procedures when they are hosted by free living amoeba and that in many cases are hardly detectable by culture-based procedures. In this work we report a sensitive, low-cost procedure consisting of a pentaplex-nested PCR that allows simultaneous detection of Legionella pneumophila, Mycobacterium spp., Pseudomonas spp., Vibrio cholerae and the microcystin-producing cyanobacteria Microcystis aeruginosa. The method has been used to detect the presence of these pathogenic bacteria in water and inside free living amoeba. Its validation in 72 samples obtained from different water sources from Aragon (Spain) evidences that Mycobacterium and Pseudomonas spp are prevailing as amoeba-resistant bacteria.

Evolution of the crystal and magnetic structure of the R2MnRuO7 (R = Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y) family of pyrochlore oxides

The members of the family of pyrochlore oxides with the formula R(2)MnRuO(7) (R = Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) have been synthesized and characterized. Polycrystalline samples were prepared by a soft chemistry procedure involving citrates of the different metal ions, followed by thermal treatments in air or O(2) pressure. The crystallographic and magnetic structures have been analysed from X-ray diffraction (XRD) and neutron powder diffraction (NPD) data, in complement with magnetic measurements; the evolution along the series of the crystallographic parameters (unit-cell parameters, bond distances and angles) is discussed. In R(2)MnRuO(7) pyrochlores, Mn and Ru ions statistically occupy the 16c sites in a cubic unit cell with space group Fd ̅3m, which defines an intrinsic frustrated three-dimensional system. In all the cases, the low-temperature NPD data unveils an antiferromagnetic coupling of two subsets of Mn(4+)/Ru(4+) spins, indicating that the magnetic frustration is partially relieved by the random distribution of Mn and Ru over the 16c sites. At lower temperatures there is a polarization of the R(3+) magnetic moments, which also participate in the magnetic structure, when a magnetic rare earth is present.

Rhizobium promotes non-legumes growth and quality in several production steps: towards a biofertilization of edible raw vegetables healthy for humans

The biofertilization of crops with plant-growth-promoting microorganisms is currently considered as a healthy alternative to chemical fertilization. However, only microorganisms safe for humans can be used as biofertilizers, particularly in vegetables that are raw consumed, in order to avoid sanitary problems derived from the presence of pathogenic bacteria in the final products. In the present work we showed that Rhizobium strains colonize the roots of tomato and pepper plants promoting their growth in different production stages increasing yield and quality of seedlings and fruits. Our results confirmed those obtained in cereals and alimentary oil producing plants extending the number of non-legumes susceptible to be biofertilized with rhizobia to those whose fruits are raw consumed. This is a relevant conclusion since safety of rhizobia for human health has been demonstrated after several decades of legume inoculation ensuring that they are optimal bacteria for biofertilization.

Internacionalización de la producción científica de España en Radiología y Neuroimagen (1996-2003)

The situation of Research in radiology in Spain is analysed by examining the number of publications by Spanish authors in main stream international journals. The scientific production of Spanish researchers in journals included in the Science Citation Index (SCI) under the headings "Radiology, Nuclear Medicine, and Medical Imaging" and "Neuroimaging" during the years 1996-2003. During this period the scientific production in these fields comprised 1,562 documents (3.5% of the total production for Spanish clinical medicine); scientific production in these fields increased by 40% in this period in comparison to 24% for all clinical medicine. The bulk of the production was concentrated in the autonomous communities of Catalonia (35%), Madrid (28%), and Valencia (10%). The autonomous communities of Navarra and Cantabria had a high relative production after the results were adjusted for population. The healthcare sector is the most active, with the Hospital de la Santa Creu i Sant Pau, the Hospital Clinic de Barcelona, and the Hospital Vall d'Hebron being outstanding in that they not only lead the country in the number of publications but also publish more in journals with high impact factors. Among centers other than hospitals, the Center for Research in Energy, the Environment, and Technologies (CIEMAT) and the Medical School of the Universidad Complutense de Madrid are the most important. A high degree of collaboration is evident: 68% of the documents were produced by more than one institution, foreign centers were involved in 20%, and the documents were signed by an average of six authors. Conclusions. In summary, the data show that Spanish radiological research is becomin increasingly international, although this process is still in the initial stage, with the percentage of documents published in the most prestigious journals for this specialty being lower than in other disciplines. The relative activity and production of Spain is slightly below the average of the European Union, but the country shows a rising trend for both production and impact.

[Localization of lung nodules with CT-guided hookwire before videothoracoscopic surgery]

PURPOSE

To localize peripheral lung nodules under CT guidance using hookwires, prior to video-assisted thoracic surgery (VATS).

PATIENTS AND METHODS

Twenty-two pulmonary nodules were localized with a hookwire under CT guidance. The visceral pleura was stained with methylene blue. VATS was performed thereafter.

RESULTS

All nodules were successfully localized and resected without significant complications.

CONCLUSIONS

In select cases, localization of pulmonary nodules with hook wire and methylene blue allows the thoracoscopic resection of unaccessible lesions.

[Spanish scientific production in biomedicine and health sciences during the period 1990-1993 (Science Citation Index and Social Science Citation Index) and comparison to period 1986-1989]

BACKGROUND

In 1993 a first study on the scientific production of Spain in 1986-1989 on Biomedicine and Health Sciences, through the Science Citation Index (SCI) was published. The analysis attained the level of centres, with special emphasis in those related to the Health Care System. This paper analyses the period 1990-1993, offers a wider coverage including the Social Science Citation Index (SSCI) database, and compares both time periods.

MATERIAL AND METHODS

Documents indexed by SCI and SSCI, CD-ROM version, with at least one Spanish address, published in biomedical and medical journals during the years 1990, 1991, 1992 and 1993, have been studied. Quantitative and qualitative bibliometric indicators for the analysis by subject matter, geographic distribution, institutional sector and centre of origin have been used. Global data were also analysed according to economic and human resources.

RESULTS

A total of 21,434 documents were studied, of which 67.9% were journal articles. The highest contributors were Universities (48.8% of the documents) and Hospitals (45.3%). The autonomous communities of Madrid (31.9%) and Catalonia (26.9%) concentrate more than half the production-developed principally by hospitals-followed by Andalucía (11.7%) and C. Valenciana (7.8%). The most active disciplines were biochemistry/molecular biology (13%), neurosciences/neurology (8.4%), pharmacology/pharmacy (8.4%) and medicine, general/internal (7.9%). Comparing the results with period 1986-1989, some of the differences observed could be explained by the fact of MEDICINA CLINICA being included in SCI since 1992. An increase in the number of citable items (72.9%), number of journals used (from 1,086 to 1,346) and international cooperation rate (13.5% to 18.3%) was detected. The institutional sectors with the highest growth rate were Hospitals (92.9%) and Consejo Superior de investigaciones Cientificas (CSIC) (119.3%). Scientific production and visibility of publications (measured as impact factor of journals used) grew in most disciplines, being the quantitative increase greater in cancer/oncology, gastroenterology/hepatology, genetics/heredity and cardiovascular system. No substantial changes as to geographic distribution of documents or most active centres were observed.

CONCLUSIONS

Spanish scientific activity grew steadily every year and its visibility improved, being the Health sector one of the main actors. When comparing both four-year period. Spain moved up from the seventh to the sixth position in the ranking of EU countries according to its scientific output in biomedicine and health sciences.

Epidermal dysplasia and neoplasia in kidney transplant recipients

BACKGROUND

Established data confirm an increased incidence of skin cancer, mainly squamous cell carcinoma (SCC), in long-term kidney transplant recipients (KTRs).

OBJECTIVE

Our purpose was to investigate prospectively the type and frequency of neoplastic and preneoplastic skin lesions in KTRs during the first 3 years of immunosuppression, as well as the influence of potential risk factors.

METHODS

Eighty-one consecutive KTRs were examined every 6 months during the first 3 years after transplantation. All survival analyses were performed with the EGRET statistical software package.

RESULTS

After a median follow-up of 34 months, 25 skin cancers developed in 12 patients; the basal cell carcinoma (BCC)/SCC ratio was 3.1:1. The cumulative risk of skin cancer developing after 3 years of graft survival was 18.1%. Only age at the time of transplantation (p = 0.005) and occupational sun exposure (p = 0.048) had statistical significance as risk factors.

CONCLUSION

In carefully supervised KTRs, a high incidence of cutaneous malignancy, mainly BCC, exists in the early posttransplant period. Sun exposure and the patient's age at the time of transplantation seem to be the most important risk factors.

[Spanish scientific production in biomedicine and health. A study via the Science Citation Index (1986-1989)]

BACKGROUND

There is no detailed information on the scientific production in biomedicine from the perspective of the centers which make up the National Health Care System. Nor has any analysis on productivity by specialties compared with that of other countries of the European Community (EC) been carried out.

METHODS

The methodology used and the global results of a study performed from biomedical investigation documents indexed in the SCI from 1986 to 1989 and signed by a Spanish health care center are presented. Quantitative and qualitative indicators (Narin index, impact factor [IF], mean IF per specialty, expected and observed IF as well as denominators [PIB, number of inhabitants per area, cost and number of personnel of the centers]).

RESULTS

Twelve thousand seven hundred and six documents were studied of which 66.7% were journal articles and 13.5% were studies carried out in cooperation with foreign countries. The biomedical production was 41.5% of all the Spanish scientific investigation collected in the SCI in the same period and represented 3.82% of the contribution of all the biomedical investigation of the EC. Universities were responsible for 46% of the documents analyzed followed by hospitals with 39%. The autonomic communities of Madrid (32%) and Catalonia (26%) have the most productivity principally in hospitals, followed by Andalucia (10%) and Valencia (7%). The subject matters of greatest production were biochemistry, and molecular biology (14.7%), pharmacology and pharmacy (7.6%), neurosciences (6.8%) and microbiology (5.7%). Qualitative analysis showed that despite the investigation in some subject areas being carried out in journals with an IF higher than the world mean, the citations received by the studies are lower than expected.

CONCLUSIONS

Despite the growth in Spanish biomedical production, Spain only occupies seventh place in the EC. Madrid and Barcelona notably concentrate on biomedical investigation from the hospital network. The relativization of the data describes the existence of other noteworthy geographic areas not outside the university. The ever greater diffusion of the publications contrasts with the citations received for the studies which may be the result of phenomena related with the quality of the studies and/or the recognition of the publications signed by Spanish authors.

The high affinity murine laminin receptor is a member of a multicopy gene family

The high affinity laminin receptor is differentially expressed in metastasis. We now report that there are multiple copies (6 +/- 1) of the laminin receptor gene in the murine genome of normal diploid cells as well as in cell lines derived from cancer cells. We have analyzed three distinct cDNA clones isolated from an Okayama-Berg cDNA library of transformed mouse fibroblasts that may represent transcripts of three different laminin receptor genes. Polymorphic changes include insertion of bases at the 5' terminus, a base substitution within the coding region resulting in an amino acid change from phenylalanine to leucine, a base substitution obliterating a polyadenylation signal, as well as changes in the length of the 3' untranslated domains. The discovery of multiple transcripts of laminin receptor genes suggests that there is a strong selective pressure to maintain laminin receptor expression in murine cells.

The marine toxin okadaic acid is a potent neurotoxin for cultured cerebellar neurons

The tumor promoter okadaic acid (OKA), is a marine toxin of algal origin, identified as a potent inhibitor of protein phosphatases 1 and 2A, and possibly enhancing calcium influx through voltage dependent calcium channels (VSSC). We now report that OKA at concentrations as low as 0.5 nM produced neurotoxicity, characterized first by the desintegration of the neurites and swelling of cell bodies, and later by cellular death. Non-neuronal cells viability and morphology were unaffected up to at least 5 nM OKA. Neurons sensitivity to the toxin changed with age in culture. Maximum neurotoxicity was observed in neurons at 9 DIC, when the OKA concentration producing half of the maximum reduction in neuronal survival (EC50) was approximately 0.65 nM. At 5 DIC or 19 DIC (EC50 approximately 2.5 nM and approximately 4.5 nM respectively), neurons appeared to be less sensitive to OKA. Neurotoxicity by OKA was not reduced by VSCC antagonists such as nifedipine and verapamil, nor by antagonists of excitatory aminoacid (EAA) receptors including APV, MK801 or CNQX. VSCC antagonists and EAA receptors antagonists fully protected from neurotoxicity induced by depolarization with KCl. These results suggest that OKA mechanism of neurotoxicity may not directly involve VSCC, endogenous EAA release and EAA receptors, but may depend upon other neurochemical events.

[Microcystic cystadenoma of the pancreas]

Cystadenoma of the pancreas is a rare tumor. In the surgery unit of the Hospital de la "Santa Cruz y San Pablo", of 18 cases of cephalic duodeno-pancreatectomy in the last nine years, we have only observed one case of cystadenoma. The patient was a 70 year-old woman, hypertensive and very obese, who had few symptoms and was diagnosed as pancreatic tumor by echography. CAT, ERCP and abdominal arteriography confirmed the diagnosis. Needle biopsy guided by echography and CAT was negative for malignant cells. In the operation, needle and trucut biopsy revealed benign cystadenoma. Cephalic duodenopancreatectomy was performed. The postoperative period was difficult, and the patient required reoperation within hours for intraperitoneal hemorrhage and again, eight days later, for dehiscence of the pancreatic suture. Finally she recuperated and was released at 38 days. Of all the types of proliferative pancreatic cysts, microcystic or serous adenoma is benign, as compared to mucinous cyst, of clearly malignant potential. However, needle biopsy rarely provides differential diagnosis. In some cases of high surgical risk, the indication for resection can be dubious if the cyst lies in the region of the pancreatic head and its benign nature can be demonstrated.

Proteolysis of hexokinase PII is not the triggering signal of carbon catabolite derepression in Saccharomyces cerevisiae

The role of hexokinase PII in mediating carbon catabolite derepression in yeast has been examined. Hexokinase isoenzyme PII (EC 2.7.1.1) was partially degraded when protease inhibitors were omitted from the buffer used for preparation of cell-free extracts. The hexokinase PII inactivation induced by D-xylose was correlated with derepression of maltase (EC 3.2.1.20) in the wild-type strain Saccharomyces cerevisiae G-517 and in D.308.3, a strain that contains the cloned hexokinase PII gene on a multicopy plasmid. This inactivation was not correlated with the loss of hexokinase PII protein as assayed by immunoblotting. We conclude that during the derepression process there is no release of proteolytic peptides from hexokinase PII.

Mechanism of inactivation of hexokinase PII of Saccharomyces cerevisiae by D-xylose

The mechanism of inactivation of hexokinase PII of Saccharomyces cerevisiae by D-xylose was characterized. Inactivation was dependent on the presence of MgATP and was irreversible. Inactivation involved phosphorylation of the protein. Observation of the carbon catabolite repression of selected enzymes showed that invertase and maltase synthesis were not repressed when hexokinase PII was phosphorylated.