Thermal behaviour of a heterothermic enzyme: A4 lactate dehydrogenase from Triturus cristatus

The behaviour of T. cristatus A₄ lactate dehydrogenase at different temperatures was studied on the pure isoenzyme. The molecule displays a number of properties which do not conform to any current model of biochemical adaptation to temperature. Our hypothesis is that the structure of newt LDH evolved is such a way to become able to sustain its physiological action over the entire thermal range of the species, and thus no adjustment in kinetic features is needed when temperature varies.     

Evidences of olive pollination date variations in relation to spring temperature trends

Airborne pollen concentration patterns reflect flowering phenology of a given species, and it may be a sensitive regional indicator in climate change studies. This paper presents the relationship between a strategic biological event, such as olive flowering, and the air temperature trend, registered over a large scale (1982–2007) in the Umbria region. The aim of the study was to determine relationships between phenological behaviour (flowering) of olive trees and the air temperature trend (1982–2007) in the Umbria region. The phenological data on flowering phase were registered indirectly through an aerobiological monitoring technique. The obtained results showed a strong relationship between phenology and thermal trend. This characteristic was confirmed from results of correlations between temperature (mean temperature from 1st March) and flowering dates, especially that of full flowering (r = −0.9297). Moreover, the results showed an advance trend of 6, 8 and 10 days, respectively of start, full and end of flowering dates. The advance of the recorded flowering time in this period is to ascribe mainly to the increase of mean temperature and above all to that registered in months of May and June.     

Role of alpha-fetoprotein in selection of patients with hepatocellular carcinoma waiting for liver transplantation: must we reconsider it?

Background: Milan criteria (MC) represent the most commonly adopted criteria for the selection of patients with hepatocellular carcinoma (HCC) waiting for liver transplantation (LT). However, MC are exclusively based on morphological aspects. The aim of the present study was to evaluate pre-LT-detectable biological parameters, to compare them with morphological ones in terms of tumor recurrence prediction and patient survival. Methods: A cohort of 153 consecutive adult patients who underwent LT for HCC on cirrhosis from January 1999 to March 2009 was retrospectively analyzed. Results: HCC recurrence was observed in 12 patients (7.8%). At multivariate logistic regression analysis, serum alpha-fetoprotein (AFP) was the unique independent negative risk factor for the development of HCC recurrence (odds ratio 2.0, p=0.03). Adopting a cutoff value of 210 ng/mL, patients who presented serum AFP =210 ng/mL showed a 5-year survival rate of 23.3% versus 76.2% observed in patients with pre-LT serum AFP <210 ng/mL (log-rank test: <0.0001). Conclusions: In our experience, AFP was the strongest predictor of HCC recurrence, stronger than tumor morphology. AFP could ameliorate the selection of LT candidates. Further studies to evaluate the combination of morphological and biological criteria are needed.     

Fluorescence-assisted mismatch analysis (FAMA) for exhaustive screening of the α-galactosidase A gene and detection of carriers in Fabry disease

We used the fluorescence-assisted mismatch analysis (FAMA) method to screen rapidly the α-galactosidase A gene in patients with Fabry disease in order to identify unknown mutations and help define genotype-phenotype correlations in this X-linked lysosomal storage disorder. Chemical cleavage at mismatches on heteroduplex DNA end-labeled with strand-specific fluorescent dyes, reliably detects sequence changes in DNA fragments of up to 1.5 kb and locates them precisely. Exhaustive scanning of the α-galactosidase gene was accomplished on four polymerase chain reaction-generated amplicons, covering all seven exons, the exon-intron boundaries, and 700 bp of 5′-flanking sequence. Mutations were identified in each of the 15 patients studied from nine unrelated kindreds. Among the seven previously undescribed sequence changes, three are obviously pathogenic because they lead to premature protein termination. The other four, a splice-site mutation and three missense mutations, were the only changes found upon complete scanning of the gene and its promoter. In addition, FAMA also detects female heterozygous carriers more dependably than direct sequencing, and thus provides a valuable diagnostic test. In Fabry disease, this molecular criterion is especially important for genetic counseling since heterozygotes can be asymptomatic and their enzymatic values within the normal range. Received: 9 April 1996 / Revised: 8 July 1996