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Biomedical subjects

A Messina

Publications and source records attributed to A Messina.

At least 19 recordsLinked to original sources
PubMed1997

Simultaneous assay for aspartate aminotransferase and guanase in human serum by high-performance liquid chromatography.

A simple high-performance liquid chromatography (HPLC) assay for the simultaneous determination of guanase and aspartate aminotransferase (AST) activities in a single serum sample is described. The method is based on direct detection of enzymatically formed products xanthine and glutamate, respectively. The procedure is sensitive, precise (C.V. below 2% for guanase and 3% for AST), suitable for routine purposes and requires only 100 microliters of sample. Kinetic measurements have shown the guanase activity to have an apparent Michaelis constant of 24.5 microM and the AST activity of 11.1 and 0.18 mM for aspartate and oxoglutarate, respectively, at 37 degrees C in Tris-HCl buffer (pH 7.5).

Aspartate Aminotransferases↗
PubMed1997

The S-adenosyl-L-homocysteine hydrolase of Drosophila melanogaster: identification, deduced amino acid sequence and cytological localization of the structural gene.

S-adenosyl-L-homocysteine hydrolase (AdoHcyase, EC 3.3.1.1) catalyzes the hydrolysis of S-adeno-syl-L-homocysteine to adenosine and homocysteine and thus plays a crucial role in normal cellular metabolism. We have isolated the cDNA for Drosophila melanogaster AdoHcyase by screening a Drosophila ovarian expression library. The 1584-nucleotide cDNA encodes a protein of 431 amino acids, showing 80.5% identity with human AdoHcyase. Southern analysis of genomic DNA and in situ hybridization to salivary gland chromosomes indicate that a single gene encodes the D. melanogaster AdoHcyase. The gene resides in region 13C1-2 on the X chromosome. Transcript analysis shows a single AdoHcyase mRNA present in unfertilized eggs, and, at a more or less constant level of expression, in all developmental stages tested, ranging from early embryos to adults. The deduced amino acid sequence was compared to a putative AdoHcyase-like protein encoded by a cDNA mapping to the 89E region of the second chromosome and showing much lower similarity to known AdoHcyases. We discuss the hypothesis that a sequence that originated by duplication of an ancestral AdoHcyase gene has, in the course of evolution, been recruited to supply a different function.

Adenosylhomocysteinase↗
PubMed1997

Nuclear factor-kappaB activation in human monocytes stimulated with lipopolysaccharide is inhibited by fibroblast conditioned medium and exogenous PGE2.

The nuclear factor kappaB (NF-kappaB) is thought to be crucially involved in the gene activation of several cytokines, including tumor necrosis factor alpha (TNF). Previously, we showed that fibroblast conditioned medium (FCM) is able to inhibit both TNF mRNA accumulation and protein release in peripheral blood-derived human monocytes (PBM) stimulated with lipopolysaccharide (LPS). In this study we have investigated the effect of FCM on the LPS-induced DNA-binding activity of NF-kappaB, by means of electrophoretic shift assay (EMSA). We provide evidence that FCM strongly inhibits the LPS-induced NF-kappaB activation in PBM. Furthermore, we show that exogenous PGE2 mimics the NF-kappaB inhibitory effect of FCM. On the other hand, FCM produced in the presence of indomethacin does not inhibit NF-kappaB activation by LPS. Our results lend further support to the hypothesis that inflammatory and immune responses of monocytes/macrophages may be modulated at the molecular level by signals originating from tissue structural cells such as fibroblasts.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

Detection of jun but not fos protein during developmental cell death in sympathetic neurons.

A large proportion of neurons die during normal development of the nervous system via an active process known as apoptosis. We counted the total number of neurons and apoptotic neurons in the superior cervical ganglion of the GH Wistar rat strain, which possesses a neurotrophic deficit leading to excessive perinatal cell death, and in its normal counterpart (N) by using the optical disector method to quantify the extent of apoptosis during postnatal development. Total neuron numbers fell between postnatal days 3 and 14 by 10 and 40% in N and GH, respectively. In GH ganglia, 1.5% of neurons were apoptotic at any given time, as determined by the presence of condensed chromatin clumps. Some types of cell death have been associated with expression of the immediate-early genes c-fos and c-jun. Therefore, we used histological and immunocytochemical techniques to characterise individual neurons and to detect the products of these immediate-early genes during developmental cell death. All apoptotic cells were immunopositive for c-jun protein, whereas no c-jun protein was detected in nonapoptotic cells. Conversely, members of the fos family of transcription factors were detected in the nucleus of 60% of nonapoptotic cells but in only a minor proportion of cells undergoing apoptosis. These results indicate that c-jun occurs in neurons that are committed to die. This is the first situation in which the presence of jun protein has been correlated with normal programmed cell death in individual apoptotic neurons.

Aging↗
PubMed1996

Cloning and chromosomal localization of a cDNA encoding a mitochondrial porin from Drosophila melanogaster.

We have raised polyclonal antibodies against purified the Drosphila melanogaster mitochondrial porin. They showed high titre and specificity and were thus used as a tool for screening an expression library. The isolated clone 1T1 showed 74% sequence identity in the last 19 residues at the C-terminus of human porin. A subclone of 1T1, containing the porin-like sequence, was thus used as a probe for re-screening a cDNA library and several positive clones were plaque-purified. We present here the sequence of a 1363 bp cDNA encoding a protein of 279 amino acids. Its identity with porin was also confirmed by N-terminal Edman degradation of the purified protein. The D. melanogaster porin shows an overall 51.8% identity with human porin isoform 1 (porin 31HL or HVDAC1) and an overall 55.7% identity with human porin isoform 2 (HVDAC2). Hydrophobicity plots and secondary structure predictions showed a very high similarity with data obtained from known porin sequences. The D. melanogaster porin cDNA was used as a probe for in situ hybridization to polytenic salivar gland chromosomes. It hybridizes with different intensities in two sites, in chromosome 2L, at region 31E and in chromosome 3L at region 79D. Thus, also in Drosophila melanogaster porin polypeptide(s) belong(s) to a multigene family.

Amino Acid Sequence↗
PubMed1996

MR cholangiopancreatography (MRCP) at 0.5 T: technique optimisation and preliminary results.

The aim of our study was to evaluate the feasibility of MR cholangiopancreatography (MRCP) at 0.5 T. To our knowledge no previous studies of MRCP have been performed at mid-field strength. Thirty-one patients with dilated biliary systems were examined with three-dimensional MRCP. All patients were studied with a 0.5 T superconducting magnet. A three-dimensional turbo spin-echo (TSE) sequence was acquired (TR = 5000 ms, TE = 244 ms, echo train length = 45; acquisition time = 14 min 10 s). Coronal images were post-processed with the MIP algorithm. Recently, the parameters have been optimised (TR = 3000 ms, TE = 700 ms, echo train length = 128), reducing the acquisition time to 3 min. Endoscopic retrograde cholangiopancreatography (ERCP) was performed in 26 cases; 5 patients underwent percutaneous transhepatic cholangiography PTC. MRCP and ERCP images were evaluated by an experienced radiologist and an endoscopist. MRCP of diagnostic quality was acquired in all patients. Choledocholithiasis was correctly evaluated by MRCP in 12 of 12 patients, compared with 11 correct diagnoses by ERCP. The presence and the level of the stricture were accurately shown in 16 of 16 patients with MRCP and in 13 of 16 patients with ERCP. The peripheral biliary tree above the obstruction and pancreatic duct were better evaluated by MRCP in all cases. In 3 of 3 patients who had undergone bilio-enteric surgery, a correct evaluation of the site of the anastomosis was possible with MRCP. It is concluded that MRCP performed at mid-field strength allows good visualisation of the dilated biliary system. Excellent results have been obtained on comparison with ERCP. MRCP performed at mid-field strength could have the same clinical value as high field strength MRCP.

Adult↗
PubMed1996

Microfilament system in the microvascular endothelium of the palmar fascia affected by mechanical stress applied from outside.

The effect of externally applied mechanical stress was investigated by thin section electron microscopy of the microvessels in the unaffected palmar fascia in the carpal tunnel syndrome and in patients with Dupuytren's contracture before and after application of a continuous elongation device. In the unaffected palmar fascia the microfilaments of the endothelial cells were connected to a few adherens junctions and focal contacts; stress fibres were absent. In the cord of Dupuytren's disease the microfilaments were increased in quantity. The length ratios of the connections with the lateral and basal cell membrane were significantly higher than in the control group and increased to an even greater extent in the continuously extended fascia. Stress fibres appeared in the endothelial cells of postcapillary venules in the nonextended cord and in the endothelium of both arterioles and venules after extension elongation. the numerous intermediate filaments and the rare microtubules remained unchanged in the endothelial cells of all palmar fasciae analysed. In the endothelial cells of the microvessels the mechanical stress applied from outside mainly affected the contractile component of the cytoskeleton.

Actin Cytoskeleton↗
PubMed1996

The direct midlateral approach with lateral enlargement of the pulley system for repair of flexor tendons in fingers.

The direct midlateral approach and the lateral enlarging procedure of the pulley system have been utilized in our service since 1972. The incision runs directly behind the neurovascular pedicle, which is left in the palmar skin flap of the anterior compartment of the finger, in order to ensure its blood supply and sensibility. The transverse digital lamina of Landsmeer's skin anchoring system and Cleland's ligament are preserved and are used to perform a lateral enlargement of the pulleys after tendon repair. The technique allows wide surgical exposure of the digital fibro-osseous tunnel, enlargement and reconstruction of the pulley system and tendon sheath, flexor tendon repair (using the technique of choice) and reduces postoperative impingement in zone 2.

Finger Injuries↗
PubMed1996

Decreased developmental cell death in sympathetic and spinal sensory nervous systems of the Kyoto spontaneously hypertensive rat.

OBJECTIVE: To investigate the hypotheses that Kyoto spontaneously hypertensive rats (SHR) possess more sympathetic neurons than do normotensive Wistar-Kyoto (WKY) animals due to reduced perinatal cell death and that this is due to increased availability of the sympathetic survival neurotrophin, nerve growth factor. METHODS: Total cell counts of neuron numbers were performed in neonatal and adult SHR and WKY rat superior cervical ganglia and correlated with counts of apoptotic cells. The values for sympathetic neuron numbers were compared with those for a spinal sensory ganglion. Immunocytochemistry was used to obtain more information about the phenotypes of neurons counted. RESULTS: Adult SHR sympathetic ganglia contained about 25% more sympathetic neurons than did those of WKY animals. Similar elevation of numbers was found both for neurons containing and for those devoid of neuropeptide Y. In neonatal animals, in contrast, there was no strain difference in sympathetic cell numbers but the number of apoptotic cells was reduced in SHR. Spinal sensory neuron numbers in adult SHR were elevated to a similar extent as were sympathetic neurons, but biochemical and morphometric data suggested that this change does not involve cells that are sensitive to nerve growth factor. CONCLUSIONS: Although our results support the view that there is reduced developmental cell death both in sympathetic and in sensory systems, they also suggest that this is unlikely to be due to a simple excess of nerve growth factor during development.

Age Factors↗
PubMed1996

Human lung fibroblasts inhibit tumor necrosis factor-alpha production by LPS-activated monocytes.

Mononuclear phagocytes are important regulators of normal immune, inflammatory, and fibrotic responses. These functions are mediated through the production of several cytokines, including tumor necrosis factor-alpha (TNF-alpha), which regulate the activity of inflammatory and tissue structural cells such as fibroblasts. It is increasingly evident that fibroblasts are also capable of releasing a number of cytokines and soluble factors that can, in turn, interact with monocytes and thereby modulate the inflammatory process. In this study we provide evidence that human lung fibroblasts, through the release of soluble factors such as prostaglandin E2 (PGE2), inhibit both TNF messenger ribonucleic acid (mRNA) accumulation and TNF-alpha protein release by lipopolysaccharide (LPS)-activated human peripheral blood monocytes (PBM). Reverse transcriptase-polymerase chain reaction (RT-PCR) results showed that fibroblast-conditioned medium (FCM) caused a 50% reduction of the TNF-alpha transcript accumulation in LPS-stimulated monocytes. Furthermore, FCM induced a significant decrease in the release of TNF-alpha by LPS-activated PBM. This effect was dependent on the concentration of the FCM and the number of fibroblasts producing it. The maximal effect was seen with monocytes cultured in 100% FCM produced by 2 x 10(6) fibroblasts. This indicated that one or possibly more soluble factors released by fibroblasts were responsible for the effect. Considering that exogenous PGE2 can inhibit TNF-alpha production by PBM, and that fibroblasts are a good source of PGE2, we determined the content of PGE2 in the FCM used in our experiments. We found a good correlation (r = 0.949) between the amount of PGE2 produced by fibroblasts and the degree of TNF-alpha inhibition exerted. In addition, the inhibitory effect of FCM was mimicked by the addition to PBM cultures of exogenous PGE2 in amounts similar to those spontaneously released by fibroblasts in FCM. All of these data suggest a molecular and cellular interaction between PBM and fibroblasts that could contribute to those modulatory mechanisms involved in the self-limitation of the fibrotic process.

Cells, Cultured↗
PubMed1996

[Lithiasis of the common bile duct: the role of cholangiography and magnetic resonance].

The aim of our study was to evaluate the sensitivity, specificity and diagnostic accuracy of Magnetic Resonance Cholangiography (MR-CP) in patients with suspected choledocholithiasis. Sixty-two patients (mean age: 56.3 years) previously submitted to US, were examined with MRCP. MR exams were performed with an 0.5 T superconductive magnet (Gyroscan T5-II; Philips, Medical System, Best, NL) and a body coil. 3D-TSE sequences (TR/TE/ETL = 5.000/244/45 ms) were acquired, with 14 min 10 sec acquisition time. In the last 21 patients, acquisition time was reduced down to 3 min, by optimizing the parameters as follows: TR/TE/ETL = 3.000/700/128 ms. The images, obtained on the coronal plane, were then reconstructed with the MIP algorithm. MRCP images were studied both as MIP reconstructions and as single slices. The diagnosis was always compared with endoscopic or percutaneous findings. MRCP images were of diagnostic quality in all cases, with 91.7% sensitivity, 100% specificity and 96.8% diagnostic accuracy. MRCP had 100% positive predictive value and 95% negative predictive value. In conclusion, this technique is extremely useful to examine the patients with obstructive jaundice secondary to lithiasis.

Adult↗
PubMed1996

[Computed tomography patterns in patients treated with laparoscopic Nissen fundoplication for gastroesophageal reflux].

This work was aimed at investigating the CT anatomy in patients submitted to Nissen's fundoplication. Forty patients (mean age: 61 years) with peptic esophagitis (9 patients), refractory gastroesophageal (GE) reflux (11 patients) and hiatal hernia (20 patients) were examined. CT studies were performed with a third generation unit (CT Pace, General Electric, USA) with the patients in the prone position, after Gastrovison (Schering) and barium paste administration. In 34 patients, CT demonstrated surgery-related anatomical changes, such as the presence of a soft tissue mass at the distal third of the esophagus. In 4 patients, functional incompetence of the fundoplication (3 patients) and a recurrent hyatal hernia (1 patient) were demonstrated. In conclusion, CT studies performed with a dedicated technique permitted the accurate assessment of the anatomy of the GE junction after Nissen's fundoplication. In our study, CT demonstrated the presence of postoperative fluid collections and specific signs related to fundoplication incompetence. Our results suggest a possible application of CT to the postoperative follow-up of the patients submitted to Nissen's fundoplication, with a complementary role that of to endoscopy and functional exams.

Adult↗
PubMed1996

[Transmembrane sodium transport systems in various forms of hyperlipoproteinemia].

The possible interrelationships between the erythrocytic transport systems of Na+ (Na+/K+ pump, Na+/K+ cotransport, Na+/Li+ countertransport, Na+ passive permeability) and the plasmatic lipids (cholesterol, triglycerides, HDL, LDL, apoprotein A1, apoprotein B) were studied in 42 normotensive subjects with different forms of hyperlipoproteinaemia and with a negative familiarity for arterial hypertension. In subjects with hypercholesterolaemia (hyperlipoproteinaemia II A and II B) an elevated activity of the Na+/K+ pump was noticed, while in subjects with hypertriglyceridaemia (type IV) an increase in Na+ passive permeability and Na+/Li+ countertransport with a lower level of intraerythrocytic Na+ was shown. A negative correlation was observed between the total efflux of Na+ and Na+/K+ pump and the levels of cholesterol (r = -0.43, p < 0.04 and r = -0.41, p < 0.05) and the apoprotein B/A ratio (r = 0.42, p < 0.05 and r = -0.50, p < 0.01). A negative correlation was also noticed between the Na+/K+ pump and the levels of apoprotein B (r = -0.41, p < 0.05). The Na+/K+ cotransport appeared inversely correlated with the levels of HDL cholesterol (r = -0.42, p < 0.05), while the Na+ passive permeability was negatively correlated with the levels of LDL (r = -0.43, p < 0.04) and positively correlated with the plasmatic triglycerides (r = +0.54, p < 0.01). Such data show that the plasmatic lipids can influence the systems of transmembrane ionic transport of Na+ and play an important role also this way, in cardiovascular pathology.

Adult↗
PubMed1996

[Cholangiography with magnetic resonance in the diagnosis of main common bile duct calculi in candidates to laparoscopic cholecystectomy].

The aim of our work was to investigate Magnetic Resonance Cholangiography (MRC) capabilities in detecting common bile duct (CBD) stones in patients to be submitted to laparoscopic cholecystectomy. MRC was performed as the only preoperative imaging modality in 45 selected patients (16 men and 29 women; age range: 28-72 years, mean age: 54.4 years) before laparoscopic cholecystectomy. MRC images were obtained with 3D Turbo Spin-Echo sequences (TR = 3000 ms, TE = 700 ms, echo train length = 128) with an acquisition time of 5 min 48 sec. Diagnostic confirmation was obtained in all the patients at intraoperative cholangiography. When a stone was detected, it was removed by transcystic or transcholedochal approach. Eighteen of 45 patients (40%) had CBD stones. MRC correctly demonstrated 16 of 18 stones, with 88.9% sensitivity, 100% specificity, 100% positive predictive value, 90% negative predictive value and 95.6% accuracy. Despite the good results we obtained with MRC, this technique cannot be proposed as a screening method to be performed in all the patients candidate to laparoscopic cholecystectomy because of its high cost and of the limited number of MR units available. In conclusion, only selected patients should be submitted to MRC before laparoscopic cholecystectomy.

Adult↗
PubMed1995

Transposition of the ulnar nerve and its vascular bundle for the entrapment syndrome at the elbow.

Surgical findings show important alterations of the extrinsic and intrinsic vascularity of the ulnar nerve in the epitroclear groove. Current procedures are only able to solve the mechanical aspect of nerve compression. Transposition may cause additional iatrogenic ischaemic damage of endoneural vascularity if the nerve is separated from the ulnar collateral artery to achieve anterior mobilization. Our technique of transposition of the ulnar nerve with its vascular bundle maintains the advantages of anterior transposition currently in use, but is able to preserve the whole vascularity of the nerve, thus solving the biological aspect of nerve compression. This allows quicker recovery of axonal activity that was chronically compromised by the entrapment neuropathy. The technique and the results in 30 patients (90% excellent and good, 10% fair) treated since 1987 are presented.

Adult↗
PubMed1995

[Psychological and psychopathological correlates in Dupuytren's disease].

The etiology of Dupuytren's disease, a chronic and depressive lesion of the palmar aponeurosis, is still unclear. Numerous factors have been implicated, including psychopathological elements and a stressor psychosomatic response, possibly in the presence of a personality structure which may represent a diathesis. On the other hand, from a psychosomatic point of view, any psychic correlates could be secondary to somatic damage. In order to look for common psychological and psychopathological elements in the syndrome 39 patients were examined by a team of orthopedics specialised in hand surgery during the period 1990-91. All cases were studied by clinical interview, the evaluation of anamnestic data of possible psychiatric importance and the use of Rorschach and MMPI tests. The data obtained do not confirm that specific personality elements or psychopathological factors can be correlated to the clinical symptoms of Dupuytren's disease given that the results are comparable to what may be considered the characteristics of a non-selected but age- and culturally-matched population. There are only sporadic findings indicating neurotic and depressive factors, or senile involution. Likewise, no reliable and uniform stressing events were observed, or particular signs of maladaptation related to environmental reactivity or the disease itself.

Adult↗