Search PubMed⌕ Search

Biomedical subjects

A Antoniadis

Publications and source records attributed to A Antoniadis.

At least 73 records · Page 4Linked to original sources
PubMed1996

Radiological parameters associated with the evolution of degenerative scoliosis.

The risk factors related to the evolution of the degenerative adult scoliosis are investigated. A review was conducted of the the radiographs of 162 women (mean age 65 years) with degenerative scoliosis who were examined at the Research Center for Diseases of the Musculoskeletal System "Th. Garofalidis" Orthopaedic Department, at the Medical School of Athens University, during the period of 1985 through 1994. Only patients with degenerative lumbar curves greater than 10 degrees and only patients with no previous history of scoliosis were included in the study. The mean follow-up was 8 years (range 5-30 years) and for 30 patients the follow-up period was more than 10 years. The research demonstrated that the degenerative changes of the spine may relate to appearance and evolution of scoliotic curves in adults. Additionally, it was found that the risk factors that are associated with the evolution of the degenerative adult scoliosis are: curves over 30 degrees; curves having Grade II and III rotation; curves that are imbalanced and have a secondary compensatory curve that is sharp and angular at the L4-S1 level; curves in which the apex is at the L2-L3 and L3-L4 area; an intercrest line through the L5 vertebra; and vertebral translation equivalent to or more than 6 mm.

Aged↗
PubMed1996

Typing of Legionella pneumophila strains isolated in Greece by arbitrarily-primed PCR.

Genomic fingerprints from DNA of fifteen environmental and clinical strains of Legionella pneumophila serogroup 1, isolated from diverse geographic areas of Greece, during the period 1986 to 1994, were generated with arbitrarily-primed polymerase chain reaction (AP-PCR) in order to use the discriminatory power of two arbitrary primers, BG2 and M13 Forward to clarify the relationship among the fifteen isolates. Both primers were found to have the ability to discriminate strains of the same serogroup, to identify strains related to each other even though they were isolated at different times. Therefore, AP-PCR using BG2 or M13 Forward as primers, appears to be a useful tool which provides a fast and simple method for epidemiological fingerprinting.

Bacterial Typing Techniques↗
PubMed1995

Correlation of spinal canal post-traumatic encroachment and neurological deficit in burst fractures of the lower cervical spine (C3-7).

Burst fractures of the lower cervical spine (C3-7) are often associated with severe neurological injury. During the last 5 years (1987-1992) we operated on 11 patients who had sustained burst fractures together with neurological deficit. The operations were performed through an anterior approach. The burst vertebra was excised, and the defect was filled with bone graft. Implants (plates and screws) were used in 10 cases. The preoperative examination was conducted by computed tomography and revealed that in 4 patients with complete tetraplegia (Frankel grade A) there was more than 50% spinal canal narrowing, whilst in the remaining 7 patients, with various levels of incomplete tetraplegia, there was less than 50% spinal canal narrowing, resulting in considerable improvement. The above results support the hypothesis that a correlation exists between the magnitude of the spinal canal encroachment, the initial neurological deficit and the final outcome.

Adolescent↗
PubMed1995

The virus causing encephalomyelitis in sheep in Spain: a new member of the tick-borne encephalitis group.

The nucleotide and deduced primary amino acid sequence of the envelope gene of two virus isolates from the brains of Spanish sheep with encephalomyelitis, were determined and compared with those of other flaviviruses. The amino acid alignments showed that the Spanish viruses shared 95 to 96 per cent homology with the envelope protein of louping ill virus and western European tick-borne encephalitis virus. In comparison, the maximum variation in amino acid identities among strains of louping ill virus from the British Isles is 1.8 per cent. The Spanish isolates were distinguishable from all other known flaviviruses by the presence of a unique tripeptide sequence (AQR) at amino acid positions 232 to 234 in the E protein, the position at which a genetic marker for distinct flavivirus species has been identified. Other genetic markers, viz DSGHD (amino acids 320 to 324) and EHLPTA (amino acids 207 to 212), which identify the tick-borne encephalitis group within the genus Flavivirus, were present in the amino acid sequences of the Spanish virus. It is concluded that the cause of sheep encephalomyelitis in Spain is a distinct species in the tick-borne encephalitis virus group.

Animals↗
PubMed1994

Detection of human antibodies to Crimean-Congo haemorrhagic fever virus using expressed viral nucleocapsid protein.

Diagnosis of Crimean-Congo haemorrhagic fever (CCHF) virus infections is hampered by the problems of handling this human pathogen, which requires the highest levels of biological containment. Recombinant antigens were examined for their potential as non-hazardous diagnostic reagents. The nucleocapsid (N) gene of the Greek AP92 isolate of CCHF virus was sequenced from cloned PCR products and the open reading frame was identified by homology to the N protein of a Chinese isolate of CCHF virus. The N protein was expressed to high levels in a baculovirus expression system. Three N protein-derived peptides were expressed in Escherichia coli as fusions with glutathione S-transferase and the antigenicities of these proteins and the baculovirus-expressed protein were tested by ELISA. When tested with laboratory animal sera representing all seven serogroups of nairoviruses, the only reactive sera were those raised to CCHF virus (Greek, Nigerian and Chinese isolates) and, more weakly, Hazara virus. When tested with a panel of known positive and negative human sera, the baculovirus-expressed N protein, and the peptide derived from the central region of the N protein, proved to be the best for identifying CCHF virus-specific IgG.

Amino Acid Sequence↗
PubMed1994

Short-term effects of right atrial, right ventricular apical, and atrioventricular sequential pacing on myocardial oxygen consumption and cardiac efficiency in patients with coronary artery disease.

OBJECTIVE: To investigate the short-term effects of atrial, atrioventricular, and ventricular pacing on myocardial oxygen consumption, myocardial blood flow, and cardiac efficiency in patients with coronary artery disease. DESIGN: Prospective study that started at the end of diagnostic coronary angiography in 13 patients and was performed during atrial, atrioventricular, and ventricular pacing for 5 min, in random order, at 20 beats/min more than the heart rate of the patient's positive exercise test. A Baim thermodilution catheter in the coronary sinus was used to measure myocardial blood flow and oxygen consumption and a pacing electrode at the right ventricular apex and a catheter in the pulmonary artery were used to estimate cardiac output. SETTING: Referral cardiology centre. PATIENTS: 13 patients with coronary artery disease (mean (SD) age 53(5) years). All the patients had a positive exercise test and most of them (77%) had left anterior descending coronary artery disease. RESULTS: Mean (SD) cardiac output increased by 0.5(1.6) l/min during atrial pacing, increased by 0.1(1) l/min during atrioventricular pacing, and decreased by 0.8(1.2) l/min during ventricular pacing (P = 0.01 v atrial pacing, P = 0.03 v atrioventricular pacing). Diastolic pulmonary pressure increased by 6(4) mm Hg during atrial pacing, by 8.6(4) mm Hg during ventricular pacing (P = 0.02 v atrial pacing), and by 7.5(4.7) mm Hg during atrioventricular pacing. Changes in myocardial oxygen consumption and cardiac efficiency during the different pacing modes were similar. CONCLUSION: Atrial, atrioventricular, and ventricular pacing had similar short-term effects on myocardial oxygen consumption, myocardial blood flow, and cardiac efficiency in patients with coronary artery disease. Ventricular pacing, however, did not increase cardiac output.

Adult↗
PubMed1994

Effect of combination of deoxypyridoxine with known anti-proliferative or immunosuppressive agents on lymphocyte serine hydroxymethyltransferase.

Measurements of serine hydroxymethyltransferase (SHMT) in resting lymphocyte cultures showed that the level of activity of this enzyme is very low. Under the influence of mitogenic stimuli serine hydroxymethyltransferase activity is induced 5-20-fold. Addition in the cultures of 4-deoxypyridoxine (dB6), a potent antagonist of vitamin B6 coenzymes, concurrently with the mitogen, inhibits the induction of SHMT. Separate addition in the cultures of four anti-proliferative (AP) and immunosuppressive (IMS) agents, namely actinomycin, cytarabine, asparaginase and cyclosporine, led to the following observations. (1) The AP and IMS agents produce a decrease in the mitogen-induced activity of SHMT. The higher the concentration of the AP/IMS compound, the greater the decrease of enzymatic activity. (2) When a AP/IMS agent is combined with dB6 its effect on SHMT is considerably greater. (3) Ineffective concentrations of AP/IMS agents become effective when combined with dB6. (4) The observed changes in SHMT activity are not, as one would expect, the same in the case of all four drugs. (5) The combination makes it possible to use much smaller doses of these agents with much better results, at least as far as the decrease of enzymic activity is concerned. This is very promising for clinical use of AP agents in cancer chemotherapy and IMS agents in transplantation especially of the heart and lungs, because combining these compounds with dB6 will make possible to use smaller doses over a longer period of time with greater effectiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗
PubMed1992

Large parathyroid functioning carcinoma (1,200 g) presenting as a substernal goiter.

Parathyroid carcinoma is a rare tumor responsible for 0.5-5% of primary hyperparathyroidism. It is usually small (not more than 27 g) and the precise diagnosis of malignancy is made when local or distant metastases are found. We describe a case of a 37 yr old male presenting with a substernal goiter and no specific symptoms except hypertension. This mass had cysts and calcifications and it was in the anterior upper mediastinum. The patient had severe hypercalcemia (Ca greater than 14 mg/dl), high PTH levels and mild renal failure. Bone scanning showed signs of hyperparathyroidism. The patient was subjected to total thyroidectomy and removal of the mass en block. The tumor was circumscribed lobulated and mostly cystic. It weighed 1,200 g (380 g after evacuation of cysts) and measured 12 x 9 x 4.5 cm. Histologic examination showed a highly differentiated adenocarcinoma of parathyroid with metastasis in a regional lymph node. Almost 4 years later the patient is alive and well without hypercalcemia and without evidence of distant metastases.

Adenocarcinoma↗
PubMed1992

Expression of the nucleocapsid protein of Dugbe virus and antigenic cross-reactions with other nairoviruses.

The small (S) RNA segment of Dugbe (DUG) virus (Nairovirus, Bunyaviridae) encodes a single protein, the nucleocapsid (N) protein, of M(r) 49.4 kDa. cDNA derived from the complete coding region for the N protein was cloned into Autographa californica nuclear polyhedrosis virus (AcNPV) under control of the polyhedrin promoter and used to infect Spodoptera frugiperda insect cells. Western blotting analysis using monoclonal antibodies demonstrated the production of DUG N protein in the infected cells. Monoclonal and polyclonal antibodies to the N protein of Crimean-Congo haemorrhagic fever (CCHF) virus were found to cross-react weakly with the baculovirus expressed DUG N protein by Western blotting. When used in an enzyme linked immunoassay (ELISA), the DUG N protein reacted with polyclonal mouse immune ascitic fluids raised against either CCHF or Hazara viruses (both members of the CCHF serogroup of nairoviruses). Cross-reactions between DUG virus (Nairobi sheep disease serogroup) and members of other nairovirus serogroups were not detected.

Antigens, Viral↗
PubMed1992

Hemorrhagic fever with renal syndrome in an endemic area of Greece.

From 1983 to 1990, 32 patients with hemorrhagic fever with renal syndrome (HFRS) were admitted to our hospital. The diagnosis was confirmed by high IgM type titers of antibodies to Hantaan virus. All patients presented with serum and urine abnormalities suggesting renal involvement. Serum creatinine was elevated and ranged between 1.8 and 14.3 mg/dl. Proteinuria ranged between 0.5 and 6.4 g/24 h. Seven patients died due to shock or hemorrhage, while 6 patients were supported by hemodialysis or peritoneal dialysis. Five of them had a complete recovery. Two patients were discharged with some degree of renal impairment which remained stable 12-15 months later. Kidney biopsy in the first patient performed 1 year after his discharge revealed some degree of interstitial fibrosis and tubular atrophy as well as an area with ischemic and sclerosed glomeruli. We conclude that HFRS in Greece is a severe disease with a high mortality rate. The disease may cause chronic renal failure in a limited number of patients.

Adult↗
PubMed1992

Effect of pyridoxine deficiency on immunological phenomena.

Measurements of serine hydroxymethyltransferase (SHMT) in resting lymphocyte cultures showed that the level of activity of this enzyme was very low. Under the influence of mitogenic stimuli serine hydroxymethyl-transferase activity was induced 5-20-fold. Addition in the cultures of 4-deoxypyridoxine, a potent antagonist of vitamin B6 coenzymes, concurrently with the mitogen, inhibits the induction of serine hydroxymethyltransferase. Thus deoxypyridoxine exerts its effects not only at the level of the enzyme itself by antagonizing the coenzyme but also at the level of its biosynthesis. Synchronous addition of vitamin B6 with deoxypyridoxine effectively reverses the inhibitory effects. The T helper cells of the lymphocyte culture are very sensitive to deoxypyridoxine action in contrast to T suppressor cells. The effect of phytohaemagglutinin or concanavalin A on the production of interleukin-1b, interleukin-2 and interleukin-2 receptors is profoundly affected by deoxypyridoxine. These results give a deeper insight of the mechanisms by which pyridoxine deficiency causes significant reduction of humoral and cellular immune responses to antigenic stimuli. On the basis of the data of this report a detailed illustration of the events that follow the T cell activation is presented. From this investigation the enzyme serine hydroxymethyltransferase emerges as a key element in the processes of immune responses and cell proliferation. Based on this finding we advance the following two propositions for possible future medical application: (i) combination of deoxypyridoxine with immunosuppressive drugs in case of immunosuppressive therapy or organ transplantation. (ii) the enzyme presents an excellent target for chemotherapy and therefore development of special agents directed against its apoprotein may prove to be a very valuable medical tool.

Antibody Formation↗