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Biomedical subjects

G De Luca

Publications and source records attributed to G De Luca.

At least 91 records · Page 5Linked to original sources
PubMed1997

Middle cerebral artery velocimetry: different clinical relevance depending on umbilical velocimetry.

OBJECTIVE: To evaluate the role of cerebral velocimetry as a predictor of perinatal outcome in high-risk pregnancies. METHODS: Middle cerebral artery pulsatility index was measured in 576 high-risk pregnancies undergoing umbilical velocimetry. The results of both tests were evaluated with respect to the birth of small for gestational age (SGA) infants and adverse perinatal outcome, defined as perinatal death, cesarean delivery for fetal distress, or low Apgar score. RESULTS: Once umbilical velocimetry was taken into account, cerebral velocimetry did not improve the prediction of fetal growth restriction or adverse perinatal outcome. Neither test was able to predict adverse perinatal outcome in normally grown fetuses. As for SGA fetuses with adverse perinatal outcome, the simultaneous assessment of both umbilical and cerebral velocimetry did not improve diagnostic accuracy (kappa index 0.37 versus 0.41 for umbilical velocimetry only). However, within the group of high-risk pregnancies with abnormal umbilical velocimetry, the risk of being SGA and having an adverse perinatal outcome was doubled (relative risk 2.1, 95% confidence interval 1.1, 4.3) if cerebral velocimetry also was abnormal. CONCLUSION: The routine use of cerebral velocimetry in high-risk pregnancies adds little information beyond that obtained from umbilical velocimetry; however, it is useful in predicting SGA infants with adverse perinatal outcome when umbilical velocimetry is abnormal.

Blood Flow Velocity↗
PubMed1997

Characteristics of non-O1 Vibrio cholerae isolated from the effluents of a treatment plant.

We report the results of a study concerning the characteristics of 19 Non-O1 Vibrio cholerae strains isolated from the incoming sewage and the effluents of the treatment plant in Bologna (Italy). These strains were compared to those of a strain of Vibrio cholerae biotype El Tor. The behaviour of the Non-O1 Vibrios was seen to be quite similar to those of the El Tor biotype in all aspects studied and antigenic correlations were found by means of immunoblotting and cytotoxin production on VERO cells. Since these bacterial strains may be pathogenic in humans, we believe it useful to describe some of their characteristics.

Agglutination Tests↗
PubMed1997

Occurrence of gram-negative bacteria in drinking water undergoing softening treatment.

A study was carried out on the presence of Gram-negative bacteria in the municipal waters of Bologna (Italy) undergoing softening using domestic ion exchangers with an automatic disinfection mechanism. The softening process was seen to cause a 15 fold increase in 22 degrees C and 36 degrees C heterotrophic plate counts. There was a 30 fold increase in Gram-negative bacteria and their number correlated directly with temperature and inversely with active residual chlorine. Organic matter had no effect on bacterial growth. The most commonly found bacteria were various species of Pseudomonas (87.6%) (Ps. acidovorans, Ps. denitrificans, Ps. fluorescens and Ps. testosteroni) followed by Aeromonas hydrophila (5.6%) and Stenotrophomonas (Xantomonas) maltophilia (3.8% in outgoing water). Pseudomonas aeruginosa (present in 5.6% of incoming water samples and 0.4% of outgoing water) and Yersinia enterocolitica (present in 4.3% of incoming water samples and 1.1% of outgoing water) did not find favorable conditions for growth on the ion exchange resins.

Gram-Negative Bacteria↗
PubMed1996

Heparin protection against Fe2+ -and Cu2+ -mediated oxidation of liposomes.

Heparin (HE) exhibited a protective effect on liposome peroxidation induced by Fe2+ and Cu2+, decreasing the formation of both conjugated dienes and thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. The antioxidant activity was more relevant in the oxidizing system employing Fe2+ and H2O2 and generating the highly reactive OH radical. The analysis of liposome size distribution by quasielastic laser light scattering showed that: (1) the native structure of the particles was completely lost after exposure to Fenton reagent; (2) the presence of HE in the reaction mixture completely prevented the peroxidative damage on liposomes. Thus, HE acts as an antioxidant factor on membrane lipid bilayer. This suggests that HE, released from mast-cell granules during inflammatory processes, might locally protect the cell membrane from the oxidative injuries.

Copper↗
PubMed1996

The effect of cornea proteoglycans on liposome peroxidation.

Proteoglycans (PGs) from bovine cornea showed a protective effect on liposome peroxidation induced by Fe2+. Both chondroitin sulfate, dermatan sulfate-containing PG (CS,DS-PG) and keratan sulfate-containing PG (KS-PG) inhibited thiobarbituric acid-reactive substance formation when incubated with liposomes and Fe2+, CS,DS-PG being more effective than KS-PG. The native structure of PGs contributed markedly to antioxidant activity. Papain digestion of core protein reduced the protective effect of CS,DS-PG, whereas it abolished completely that of KS-PG. Apparently only hexuronate-containing glycosaminoglycan (GAG) chains may exert a significant antioxidant activity and this was confirmed using standard GAGs. Quasielastic laser light scattering was used to evaluate the structural consequence of peroxidative damage induced by Fenton reagent on liposomes. After exposure to the free-radical-generating system, a bimodal distribution of liposomes was observed, probably depending on the loss of native structure and fragmentation. Both CS,DS-PG and KS-PG prevented liposome breakdown. Again, free KS chains were ineffective against liposome damage, whereas DS and CS maintained the normal distribution of liposome size. These data support the hypothesis that PGs may represent part of the antioxidant mechanisms of organisms and suggest that modifications of PG content and/or composition might affect tissue sensitivity to oxidative stress.

Animals↗
PubMed1996

Familial intracranial hypertension: a case report.

We report the cases of a father and his daughter developing idiopathic intracranial hypertension within a few months' of each other. A second daughter is affected by uveitis, while a third daughter presented an episode of visual loss of unknown nature.

Adolescent↗
PubMed1996

Prevalence of thermophilic Campylobacter and Arcobacter butzleri in food of animal origin.

Thermophilic campylobacters and Arcobacter butzleri were looked for in 57 manually shelled egg samples and 130 raw meat samples. No bacteria were found in the egg samples, but they were, however, found in 16.1% of meat samples with a frequency varying from 2.4% (port sausage) to 37.5% (poultry). A total of 21 strains were identified, one belonging to Arcobacter butzleri (pork) and 20 to Campylobacter. The most common species was C. jejuni (16/20) followed by C. coli (4/20) and in both species biotype I was the most frequently found. Regarding the methods employed for the isolation of bacteria, no substancial difference was seen between the three media (Butzler, CCDA and Preston) although CCDA medium gave better results than Butzler and Preston media. The variable which had the most influence was the incubation temperature. A higher number of strains was obtained at 42 degrees C than at 37 degrees C.

Bacteria↗
PubMed1996

Effect of water softening and heating on microbial contamination of dental unit systems.

This study regards the quality of the water used in 4 types of dental units making use of softened and heated water, softened but non-heated water, non-softened but heated water and non-softened and non-heated water. The samples were taken from the incoming tap water, from oral rinsing cup, the air-water syringe and the ultrasound descaling hand-piece. The results showed how the water underwent a notable growth in bacteria during its passage within the circuits of the units, reaching heterotrophic total counts greatly exceeding the guidelines set down by Italian laws regarding drinking water. While the influence of softening was evident, the bacteria in the samples taken from descaling handpiece, where there is more stagnation, found excellent growing conditions also at high temperatures. In the softened and heated waters a notable growth of Pseudomonas aeruginosa was found and it is likely that this was encouraged by the combined effect of the softening and heating. As far as the origin of the contamination is concerned, the bacteria present in the water systems seem to have come from the incoming water.

Bacteria↗
PubMed1996

Comparative disinfection of secondary-treated sewage with chlorine dioxide and bromine chloride.

A comparison was made of the inactivation rates of Arcobacter butzleri, coliphages, total coliforms, fecal coliforms, fecal streptococci and heterotrophic plate count in secondary sewage effluent using chlorine dioxide (2 and 4 ppm) and bromine chloride (4 or 8 and 12 ppm) as disinfecting agents. Using these doses the ClO2 gave higher reduction percentages (on average more than 99% at 4 ppm) than those obtained with BrCl. The average values of the fecal indicators are well within the legal limits. Arcobacter butzleri was more sensitive to the disinfectants than other bacteria while fecal streptococci were seen to be more resistant. From the chemical point of view no differences were seen between the two disinfectants except that the action of ClO2 was stronger regarding BOD5 than that of BrCl. With the exception of dichloromethane, the concentration of volatile halogenated compounds showed little variation and values were often lower than detection limits.

Bromides↗
PubMed1995

The effect of heparin on Cu(2+)-mediated oxidation of human low-density lipoproteins.

The effect of heparin (HE) on the susceptibility of human low-density lipoprotein (LDL) to Cu(2+)-induced oxidation was investigated by monitoring conjugated diene formation. HE did not modify the maximum formation of conjugated diene, but increased markedly the lag phase. The plot of change in oxidation rate vs. time showed that the absolute value of Vmax was dependent on Cu2+ concentration and that HE increased the time necessary to reach Vmax. The value of constant K (the Cu2+ concentration producing a tlag of twice the minimum value) increased in the presence of HE, whereas the value of tmin (the time theoretically required for LDL oxidation at an infinite Cu2+ concentration) was not substantially affected. These results indicate that HE might play a protective antioxidant effect on LDL, probably affecting both the structural properties of the particle and the amount of Cu2+ available for the oxidation.

Antioxidants↗
PubMed1995

Consumption, behaviour and knowledge with respect to alcoholic drinks in student nurses in the province of Bologna, Italy.

A study was carried out on alcohol intake among the students of the Schools for Trained Nurses in the province of Bologna by means of an anonymous especially prepared questionnaire. The series consisted of 1077 subjects: 753 females and 324 males aged between 16 and 40. 68.2% of males and 56.8% of females drank wine, l'81.3% of males and 61.8% of females drank beer and 65.3% of males and 46.2% of females drank spirits. While beer was the most popular drink, wine was on average drank in greater quantity. Alcohol intake was significantly related to sex (higher among males), area of origin (South) and cigarette smoking. The risk attributable to alcohol abuse are well known to almost all of the sample, above all those in the 2nd and 3rd years of their course. Nevertheless their alcohol consumption was not particularly different from that of students attending other High Schools. Regarding the sources, of their information about the risks, the 'mass media' was more quoted by the oldest students while 'family' was given by the younger students; the Nursing School was more often mentioned by both sexes in the 2nd and 3rd year of course. No relation however was found between the students knowledge of risks and actual consumption.

Adolescent↗
PubMed1995

Uterine artery velocimetry and spontaneous preterm delivery.

OBJECTIVE: To evaluate if idiopathic spontaneous preterm delivery is associated with abnormal uteroplacental circulation, as assessed by Doppler velocimetry. METHODS: The study was carried out on 417 women who had Doppler velocimetry performed between 25-36 weeks' gestation and were subsequently delivered vaginally. The systolic-diastolic ratio (S/D) was computed for the uterine and umbilical arteries, and the outcomes of pregnancies with spontaneous preterm and term deliveries were compared. RESULTS: Uterine artery S/D was significantly higher (P < .0001) in the 31 patients delivered preterm, whereas no significant difference was observed in the umbilical S/D. Abnormal values of uterine S/D were detected in 58.1% of the preterm group, independent of the gestational age at examination. No significant increase in S/D was observed in patients hospitalized for preterm labor who delivered subsequently at term. Spontaneous preterm delivery was associated with increased uterine S/D among both pregnancies with small for gestational age fetuses and those with appropriately grown fetuses. CONCLUSION: Preterm delivery is associated with modifications of uterine artery Doppler velocimetry, suggesting that impaired trophoblastic invasion of the placental bed may play a role in determining preterm delivery.

Adolescent↗
PubMed1995

The energy cost of level walking in patients with hemiplegia.

The energy cost of level walking (Cw) was measured from the ratio of O2 consumption to speed (from 0.1 to 1.2 m.s-1) in hemiplegic patients (n = 20) and in a control group of healthy subjects (n = 17). Average age and body mass were 58, 54 years and 73, 78 kg, respectively. In hemiplegic patients Cw was higher than in control subjects (average value at 1.0 m.s-1 = 3.6 and 3.3 J.m-1.kg-1, respectively) and this difference increased at lower speeds (from 5.1% at 1.2 m.s-1 to 28.7% at 0.1 m.s-1).

Energy Metabolism↗
PubMed1995

Characterization of an operon encoding an NADP-reducing hydrogenase in Desulfovibrio fructosovorans.

A genomic DNA fragment from Desulfovibrio fructosovorans, which strongly hybridized with the hydAB genes from Desulfovibrio vulgaris Hildenborough, was cloned and sequenced. This fragment was found to contain four genes, named hndA, hndB, hndC, and hndD. Analysis of the sequence homologies indicated that HndA shows 29, 21, and 26% identity with the 24-kDa subunit from Bos taurus complex I, the 25-kDa subunit from Paracoccus denitrificans NADH dehydrogenase type I, and the N-terminal domain of HoxF subunit of the NAD-reducing hydrogenase from Alcaligenes eutrophus, respectively. HndB does not show any significant homology with any known protein. HndC shows 37 and 33% identity with the C-terminal domain of HoxF and the 51-kDa subunit from B. taurus complex I, respectively, and has the requisite structural features to be able to bind one flavin mononucleotide, one NAD, and three [4Fe-4S] clusters. HndD has 40, 42, and 48% identity with hydrogenase I from Clostridium pasteurianum and HydC and HydA from D. vulgaris Hildenborough, respectively. The 4.5-kb length of the transcripts expressed in D. fructosovorans and in Escherichia coli (pSS13) indicated that all four genes were present on the same transcription unit. The sizes of the four polypeptides were measured by performing heterologous expression of hndABCD in E. coli, using the T7 promoter/polymerase system. The products of hndA, hndB, hndC, and hndD were 18.8, 13.8, 52, and 63.4 kDa, respectively. One hndC deletion mutant, called SM3, was constructed by performing marker exchange mutagenesis. Immunoblotting studies carried out on cell extracts from D. fructosovorans wild-type and SM3 strains, using antibodies directed against HndC, indicated that the 52-kDa protein was recognized in extracts from the wild-type strain only. In soluble extracts from D. fructosovorans wild type, a 10-fold induction of NADP reduction was observed when H(2) was present, but no H(2)-dependent NAD reduction ever occurred. This H(2)-dependent NADP reductase activity disappeared completely in extracts from SM3. These results indicate that the hnd operon actually encodes an NAdP-reducing hydrogenase in D. fructosovorans.

Amino Acid Sequence↗
PubMed1995

Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat Sertoli cells.

The inhibitory effect of triiodothyronine (T3) given in early postnatal life on Sertoli cell proliferative activity, leading to their precocious terminal differentiation, has been demonstrated previously. However, data concerning the role of thyroid hormone on androgen metabolism of Sertoli cells during the same period are still lacking. In this study we performed a time-course investigation on the effects of T3 treatment on testosterone metabolism in Sertoli cells isolated from 2-, 3- and 4-weeks-old euthyroid rats. Triiodothyronine (3 micrograms/100 g body wt) was given ip., during the last week prior to sacrifice. Sertoli cells from all animal groups initially were cultured under basal conditions during the first 24 h and subsequently in the presence of testosterone (0.5 mumol/l) with or without T3 (1 nmol/l) for an additional 24 h. This treatment given to 2-week-old animals resulted in reduced testicular growth. As far as androgen metabolism is concerned, T3 in vivo and in vitro treatment in 2- and 3-week-old animals induced a lowering of dihydrotestosterone + 3 alpha-diol with an enhancement of the two other 5 alpha-reduced androgens. The effect was much less pronounced in the oldest group. In both 2- and 3-week-old treated rats a marked reduction of oestradiol was observed, which indicates an inhibition of aromatase activity, mainly in younger animals. This enzyme has been reported to be extremely active in Sertoli cells of rats (of the same strain) between the age of 5 and 20 days, but it decreases rapidly thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1995

[Tobacco smoking among the students of professional nursing schools in the province of Bologna].

A study into the smoking habits of the Nursing School students of Bologna Province was carried out. 1077 (97.8%) of all students answered the self administered questionnaire and 44.6% of them were current or occasional smokers. 37.2% of males and 31.1% of females were current smokers. Overall nurse students smoked in a greater proportion in respect of coecal young people and females were generally lighter smokers and smokers of light cigarettes. Age, smoking habits of parents, siblings and partners were positively associated with smoking status of students while sex, civil status, education birth area, sport practice and parents profession did not show any significant association.

Adolescent↗
PubMed1995

The role of proteoglycans in maintaining collagen fibril morphology.

The aortic wall contains various heterogenous proteoglycan populations which interact in different ways with other components of extracellular matrix. Proteoglycans (PGs) are known to provide structural support to the vessel wall as well as to influence specific physiological functions of the tissues. The aim of the present study was to investigate the effects of Chondroitinase AC (Chase), Streptococcal Hyaluronidase (Hyase) and Heparanase on human aortic wall collagen which had been treated previously with 4M GuHCl, in order to verify the effects of selective glycanolytic treatment on type I collagen fibril ultrastructure. Following 4M GuHCl treatment, collagen fibrils are seen to have a clearly visible period. Subsequent to GuHCl and Streptococcal Hyase treatment all collagen fibrils appear to be completely swollen in thin aperiodic filaments; the typical 64 nm collagen period is completely undetectable. After GuHCl and Chase treatment a small number of collagen fibrils are seen to be swollen in thin fibrils which are mainly localized at some distance from elastic fibres. Following GuHCl and Heparanase/Heparitinase III treatment a considerable number of collagen fibrils appear to be swollen in thin fibrils; the majority of which are situated in the vicinity of elastic fibrils. The swelling of collagen fibrils underlines the fundamental role of proteoglycans in maintaining collagen fibril integrity and periodicity. It is as yet impossible to precisely map interactions between these proteoglycans and collagen fibres. The role of Hyaluronic acid requires further investigation, although the nature of this interaction is undoubtedly a matter of considerable interest.

Adult↗