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Biomedical subjects

A Andreou

Publications and source records attributed to A Andreou.

At least 19 recordsLinked to original sources
PubMed2006

Assessing the effects of three dental impression materials on the isolated sciatic nerve of rat and frog.

The effects on nerve tissue of three dental impression pastes were compared in this study. Two of the impression pastes, Examix and Express 3M, contained vinyl polysiloxane while the other, Xanthopren, did not. An in vitro model based on the isolated sciatic nerve of the frog and rat was used. As an indication of the proper functioning of the fibres in the nerve, the amplitude of evoked compound action potential (CAP) was monitored continuously. The results clearly showed that the number of active nerve fibres in the isolated sciatic nerves of either rat or frog exposed directly to impression pastes containing vinyl polysiloxane, decreased much faster than those of the nerves in contact to impression material without vinyl polysiloxane. When the nerve of the frog was exposed to Xanthopren there was a decrease in the CAP to 50% of the control values within 56.87+/-2.42 h (n=6). This value was called inhibition time to 50%, IT(50) and for Examix it was found to be 9.97+/-1.53 h. When the nerve of the rat was exposed to Xanthopren, the IT(50) was 15.34+/-2.97 h (n=6) for the Xanthopren and only 2.86+/-1.20 h for Examix and 2.76+/-0.48 h for Express 3M (n=6). There was no significant difference between the action of the last two compounds (P=0.85). This fast nerve fibre inactivation could be caused either by the chemical used for the synthesis of the two impression pastes, Examix and Express 3M, or by the unusual constriction of the nerve when it is embedded in the materials with vinyl polysiloxane. There is strong evidence to support the first case, since the incubation of the nerve in the presence of Examix, Express 3M and Xantopren in a way so the nerve was not in contact with the impression pastes, shows a much faster decrease of the CAP in the presence of the first two pastes. The decrease is caused by the death of nerve fibres, since there is no recovery in the CAP after the removal of Examix from the incubating saline.

Action Potentials↗
PubMed2006

Molecular profiling of bladder tumors based on the detection of FGFR3 and TP53 mutations.

PURPOSE: On a routine basis we performed systematic molecular screening for FGFR3 and TP53 mutations in 121 bladder tumors. We then specifically analyzed the predictive value of the recurrence of FGFR3 and TP53 genotypes in superficial lesions. MATERIALS AND METHODS: The FGFR3 gene was analyzed by direct sequencing of exons 7, 10 and 15, whereas TP53 status was determined using the p53 functional assay in yeast. RESULTS: We identified a missense FGFR3 mutation in 66% of pTa, 26% of pT1 and 12% of pT2 tumors. Of activating FGFR3 mutations 54% and 85% were found in low G1 and intermediate G2 grade tumors, respectively, but in only 20% of high grade G3 tumors. We detected inactivating TP53 mutations in 10% of pTa, 42% of pT1 and 58% of pT2 tumors. Moreover, TP53 mutations were found only in 23% of grade G1 and 3% of grade G2 tumors but in 44% of high grade G3 tumors. When the 2 genotypes were combined, we observed that 58% of pTa tumors had the (mutant FGFR3, WT TP53) genotype, whereas 58% of invasive lesions harbored the inverse genotype (WT FGFR3, mutant TP53). The (mutant FGFR3, WT TP53) genotype and the (WT FGFR3, mutant TP53) genotype were detected in 23% and 38% of pT1G3 tumors, respectively. In the subgroup of 92 patients with superficial pTa-T1 bladder tumors we did not find that the TP53 or FGFR3 genotype alone or combined had a predictive value for tumor recurrence. CONCLUSIONS: Our data again represent solid proof for the pivotal role of FGFR3 and TP53 mutations in superficial and invasive bladder tumors, respectively. However, other molecular markers should be identified for borderline pT1G3 bladder tumors, which are probably at the crossroads of these 2 distinct molecular pathways.

Aged↗
PubMed2003

Multi-purpose HealthCare Telemedicine Systems with mobile communication link support.

The provision of effective emergency telemedicine and home monitoring solutions are the major fields of interest discussed in this study. Ambulances, Rural Health Centers (RHC) or other remote health location such as Ships navigating in wide seas are common examples of possible emergency sites, while critical care telemetry and telemedicine home follow-ups are important issues of telemonitoring. In order to support the above different growing application fields we created a combined real-time and store and forward facility that consists of a base unit and a telemedicine (mobile) unit. This integrated system: can be used when handling emergency cases in ambulances, RHC or ships by using a mobile telemedicine unit at the emergency site and a base unit at the hospital-expert's site, enhances intensive health care provision by giving a mobile base unit to the ICU doctor while the telemedicine unit remains at the ICU patient site and enables home telemonitoring, by installing the telemedicine unit at the patient's home while the base unit remains at the physician's office or hospital. The system allows the transmission of vital biosignals (3-12 lead ECG, SPO2, NIBP, IBP, Temp) and still images of the patient. The transmission is performed through GSM mobile telecommunication network, through satellite links (where GSM is not available) or through Plain Old Telephony Systems (POTS) where available. Using this device a specialist doctor can telematically "move" to the patient's site and instruct unspecialized personnel when handling an emergency or telemonitoring case. Due to the need of storing and archiving of all data interchanged during the telemedicine sessions, we have equipped the consultation site with a multimedia database able to store and manage the data collected by the system. The performance of the system has been technically tested over several telecommunication means; in addition the system has been clinically validated in three different countries using a standardized medical protocol.

Data Compression↗
PubMed2001

Xeroderma pigmentosum group G with severe neurological involvement and features of Cockayne syndrome in infancy.

We describe a premature, small for gestational age infant girl with micropthalmia, bilateral congenital cataracts, hearing impairment, progressive somatic and neurodevelopmental arrest, and infantile spasms. She presented a massive photosensitive reaction with erythema and blistering after minimal sun exposure, which slowly gave place to small skin cancers. Her skin fibroblasts were 10-fold more sensitive than normal to UV exposure due to a severe deficiency in nucleotide excision repair. By complementation analysis, the patient XPCS4RO was assigned to the very rare xeroderma pigmentosum (XP) group G (XP-G). One allele of her XPG gene contained a 526C-->T transition that changed Gln-176 to a premature UAG stop codon. Only a minor fraction of XPG mRNA was encoded by this allele. The second, more significantly expressed XPG allele contained a 215C-->A transversion. This changed the highly conserved Pro-72 to a histidine, a substitution that would be expected to seriously impair the 3' endonuclease function of XPG in nucleotide excision repair. In cases suspected of having XP and/or early-onset Cockayne syndrome, extensive DNA repair studies should be performed to reach a correct diagnosis, thereby allowing reliable genetic counseling and prenatal diagnosis.

Alleles↗
PubMed2000

Biomechanical stability of five stand-alone anterior lumbar interbody fusion constructs.

Anterior lumbar interbody fusion (ALIF) cages are expected to reduce segmental mobility. Current ALIF cages have different designs, suggesting differences in initial stability. The objective of this study was to compare the effect of different stand-alone ALIF cage constructs and cage-related features on initial segmental stability. Human multisegmental specimens were tested intact and with an instrumented L3/4 disc level. Five different ALIF cages (I/F, BAK, TIS, SynCage, and ScrewCage) were tested non-destructively in axial rotation, flexion/extension and lateral bending. A cage 'pull-out' concluded testing. Changes in neutral zone (NZ) and range of motion (ROM) were analyzed. Cage-related measurements normalized to vertebral dimensions were used to predict NZ and ROM. No cage construct managed to reduce NZ. The BAK and TIS cages had the largest NZ increase in flexion/extension and lateral bending, respectively. Cages did reduce ROM in all loading directions. The TIS cage was the least effective in reducing the ROM in lateral bending. Cages with sharp teeth had higher 'pull-out' forces. Antero-posterior and mediolateral cage dimensions, cage height and wedge angle were found to influence initial stability. The performance of stand-alone ALIF cage constructs generally increased the NZ in any loading direction, suggesting potential directions of initial segmental instability that may lead to permanent deformity. Differences between cages in flexion/extension and lateral bending NZ are attributed to the severity of geometrical cage-endplate surface mismatch. Stand-alone cage constructs reduced ROM effectively, but the residual ROM present indicates the presence of micromotion at the cage-endplate interface.

Adult↗
PubMed2000

Utility of brainstem auditory evoked potentials in children with spastic cerebral palsy.

In a retrospective study of 75 children with spastic cerebral palsy (CP), brainstem auditory evoked potentials (BAEP) were recorded and subsequently correlated with birthweight, gestational age, aetiology and type of CP, neuroradiological findings, additional impairments and disabilities (including the inability to walk independently). Seventeen patients (22.7%) had abnormal BAEP recordings. Thirteen of these 17 patients (76.5%) had spastic tetraplegia, 16 patients (94.1%) were full-term infants, 12 patients (70.6%) had myoskeletal problems, 9 (52.9%) had epilepsy, 16 (94.1%) had visual impairment, 13 patients (76.5%) were unable to walk independently, while all 17 patients (100%) had speech impairment and mental retardation. The aetiology of CP was prenatal in 2 of these 17 patients (11.8%) and perinatal in 15 patients (88.2%). Thirteen patients (76.5%) had cortical atrophy determined by either computed tomography or magnetic resonance imaging, two patients (11.8%) had an infarct picture and two patients (11.8%) had maldevelopment of the central nervous system. There was a definite statistically significant association between abnormal BAEP recordings and full-term delivery, perinatal aetiology of CP, spastic tetraplegia, speech, visual and myoskeletal impairments, epilepsy, mental retardation, inability to walk independently and cortical atrophy on neuroimaging (p < 0.001). We conclude that abnormal BAEP recordings in children with spastic CP are indicative of poor prognosis and associated with a "multihandicap state". BAEP testing should be incorporated into the diagnostic plan of all children with spastic CP newly referred to neurodevelopmental centres.

Cerebral Palsy↗
PubMed1997

Ilio-psoas abscess in a neonate.

A full-term, small-for-gestational-age, neonate was born 4 days after rupture of the membranes. On the 5th day of life, she developed sepsis due to Klebsiella pneumoniae. On the 18th day of life, the right hip was noted swollen with limited range of motion, but it was painless on passive movements. Ultrasonography revealed abscess of the right ilio-psoas muscle with normal appearance of the right hip joint. Surgical incision and drainage and antibiotic administration resulted in a gradual full recovery. Ultrasonography can confirm the diagnosis of this exceptional clinical entity in neonates, which is difficult to differentiate from septic arthritis of the hip.

Bacteremia↗
PubMed1996

Primary cutaneous aspergillosis in neonates: case report and review.

A premature neonate (gestational age, 26 weeks) with multiple prematurity-related problems developed primary cutaneous aspergillosis due to Aspergillus fumigatus on the 30th day of life. The infection developed in an area that had been macerated by adhesive tape. During the infection, renovation of the hospital was in progress near the neonatal intensive care unit. The infection was cured with a short course of therapy with amphotericin B. Five cases of primary cutaneous aspergillosis in neonates have been previously reported in the English-language literature. We review these cases and discuss the risk factors and favorable outcome of the disease when treatment with amphotericin B is instituted.

Amphotericin B↗
PubMed1995

Prenatal diagnosis of intracranial hemorrhage secondary to maternal idiopathic thrombocytopenic purpura: a case report.

We describe a case of a fetus who developed intracranial hemorrhage at the beginning of the third trimester of the pregnancy, possibly secondary to maternal idiopathic thrombocytopenic purpura (ITP). To our knowledge, this is the first reported case of prenatal diagnosis of fetal intracranial hemorrhage occurring in association with maternal ITP. The intracranial hemorrhage was intra- and periventricular, with the development of posthemorrhagic hydrocephalus. Cesarean section was performed at 37 weeks of gestation. The mother did well but the newborn died 2 months later. The problem of ITP of the mother in relation to pregnancy and the effects on the fetus and the infant are discussed.

Adult↗
PubMed1995

Fetal varicella syndrome with manifestations limited to the eye.

The manifestations of fetal varicella syndrome usually involve several organ systems, including skin, ocular, neurologic, gastrointestinal, and genitourinary. Although ocular anomalies have been reported to be as high as 68%, manifestations limited to the eyes is extremely rare. Herein we report the case of fetal varicella syndrome with no clinical signs other than esotropia and a chorioretinal scar.

Chickenpox↗
PubMed1991

Prophylactic intravenous administration of immune globulin in preterm infants: effect on serum immunoglobulin concentrations during the first year of life.

In a prospective study, serum IgG, IgA, IgM, and IgG subclass levels of 66 preterm infants (gestational age less than or equal to 34 weeks) were measured sequentially from birth to 12 months of life. Infants were divided into two groups, comparable for gestational age, birth weight, sex, and intensive care, on the basis of admission order: the treatment group, consisting of 33 infants who received intravenous immune globulin therapy (0.5 gm/kg at 10-day intervals) prophylactically, and the control group, consisting of 33 infants who did not receive. Twenty of the 33 treated infants received only one infusion and the remaining 13 received two to five infusions. The mean number of infusions per neonate was 1.96. Immunoglobulin measurements showed that the proportion of infants with an IgG level of greater than or equal to 7 gm/L on the tenth and thirtieth days of life was significantly higher in the treatment than in the control group (p less than 0.01). At the same ages, mean serum IgG, IgG1, and IgG2 concentrations were significantly higher in the treatment group (p less than 0.001). Thereafter levels in both groups fell progressively, reaching their lowest point between 3 and 5 months of age. During this period, profound hypogammaglobulinemia (IgG less than 2 gm/L) was observed in 3 of 33 treated and 11 of 33 untreated infants (p less than 0.05). By 3 months of age, mean serum total IgG concentrations were still significantly higher in treated than in untreated infants (p less than 0.05), but the IgG subclass concentrations were not. After the third month, no significant differences between the two groups were observed. Moreover, the sequentially measured serum IgA and IgM levels in the two groups remained comparable from birth to age 12 months. The IgG level at different ages from 3 to 12 months was not correlated with either birth weight or the number of infusions performed during the neonatal period (p greater than 0.1). We conclude that prophylactic intravenous administration of immune globulin to preterm infants with a birth weight of 1000 to 2000 gm, at a dose of 0.5 gm/kg every 10 days, results in maintenance of a satisfactory serum IgG level throughout the high-risk period for infections. Such treatment does not have a suppressive effect on subsequent serum immunoglobulin concentrations.

Birth Weight↗
PubMed1991

Cerebrocostomandibular syndrome in four sibs, two pairs of twins.

We report four sibs, two pairs of twins, with cerebrocostomandibular syndrome (CCMS). The family history was negative. All four babies had the characteristic features of CCMS, including Pierre-Robin anomalad and rib dysplasia. Cerebral involvement was evident in two of the patients who had suffered perinatal asphyxia. The presence of the syndrome in all four sibs together with the negative family history in previous generations is consistent with Mendelian autosomal recessive inheritance with high penetrance.

Abnormalities, Multiple↗
PubMed1990

Maternal indomethacin therapy in the treatment of polyhydramnios.

Fifteen patients with polyhydramnios and clinical symptoms related to excess amniotic fluid volume were treated with indomethacin therapy that was started at a mean gestational age of 27.4 +/- 2.79 weeks and discontinued at a mean gestational age of 32.9 +/- 1.83 weeks. Patients were treated with 2.0 to 2.2 mg of indomethacin per kilogram of body weight per day, either orally or by rectal suppositories. No therapy was administered after 35 weeks, and the duration of therapy was no longer than 4 weeks. The majority of fluid reduction occurred within the first week of treatment. Subsequently, a smaller but steady reduction of fluid was observed. All patients were delivered after 38 weeks with a mean birth weight of 3543 +/- 586.3 gm. Examinations of newborns at birth and follow-up at 3 months, 6 months, and 1 year revealed no adverse effects of indomethacin administration.

Administration, Oral↗
PubMed1988

Restoration of micturition using microelectric current in experimentally induced spastic urinary bladder in rabbits.

The 29 rabbits used in this study were divided into three groups, A (A1 and A2), B, and C. In subgroup A1, 4 animals were used in order to verify whether the contact of an electrode to the sacral nerves results in some abnormality of voiding reflex. In subgroups A1 and A2 (4 animals each) we further studied the micturition function using three parameters: (i) urinary bladder fluoroscopy and radiography, (ii) cystomanometry, and (iii) electromyography of the pelvic floor muscles (external sphinter). In group B (9 rabbits) spastic paraplegia and micturition disturbances resulted from spinal cord compression that was induced by inserting a balloon catheter into the T11-T12 intervertebral foramen. In this group the parameters studied revealed a spastic urinary bladder in all animals. Finally, the 12 animals of group C were rendered paraplegic as described in group B, and microelectrodes were placed over the sacral nerves as in subgroup A1. By applying a specific sequence of sacral nerve stimulation we succeeded in satisfactory urinary bladder emptying as confirmed by the micturition parameters studied: The urinary bladder pressure decreased from 65 +/- 3 to 28 +/- 3 mm Hg. The pelvic floor muscle amplitude was lowered from 130 +/- 7 to 20 +/- 3 microV, and finally the radiological bladder size also decreased from 38 cm2 before voiding to 18 +/- 3 cm2 after voiding. These results indicate that microelectric current stimulation of the sacral nerves, when applied under a specific sequence, could rather satisfactorily restore micturition disturbances, at least in this experimental animal.

Animals↗
PubMed1987

Prostaglandin E2 administration in infants with ductus-dependent cyanotic congenital heart disease.

Prostaglandin E2 was administered to 22 newborns with ductus-dependent cyanotic congenital heart disease. Twelve patients had pulmonary atresia and ten simple dextrotransposition of the great arteries. Patients were classified into two groups: group 1 (n = 11) received prostaglandin E2 by the intravenous route (dose: 0.01-0.05 microgram/kg per min); group 2 (n = 11) received prostaglandin E2 by the oral route (dose: 35-65 micrograms/kg per 1-4 h). Treatment lasted for 1-90 days. All infants except one of group 2 showed a significant (greater than 10 Torr) increase in PaO2 following PGE2 administration. The mean increase in PaO2 was higher (P less than 0.01) in group 1 (21.8 +/- 1.7, Torr) than in group 2 (15.8 +/- 1.5, Torr). PaO2 fell significantly (P less than 0.01) in five patients of group 1 who continued treatment orally with satisfactory (greater than 30 Torr) levels in four of them. Severe side effects were observed only in group 1. The data show that similarly to prostaglandin E1 infusions, prostaglandin E2, given i.v. or orally, is useful in the management of infants with ductus-dependent cyanotic congenital heart disease. Oral prostaglandin E2, administration is less effective than i.v. infusions, but can be used for long-term, therapy being more convenient and causing minimal morbidity.

Administration, Oral↗
PubMed1987

Improvement of cerebral circulation by extracorporal collateral between the femoral and the external carotid artery in experimentally induced ischaemia.

The purpose of this study was to examine the effect of extracorporal collateral circulation (ECCC) between the femoral and the external artery (ECA) on the cerebral circulation, in experimentally induced ischaemia, in rabbits. The animals were divided in four groups. Seven animals (Group A) were used to determine the injection pressure (150-160 mmHg) at the ECA, necessary to achieve collateral circulation between ECA and internal carotid artery (ICA), after occlusion of ICA. Group B (8 rabbits) was the control group for establishing cerebral ischaemia (CI) by a) ligating the common carotid artery bilaterally, b) coagulating the right vertebral artery and c) exsanguinating the animal (removing 28-30 ml of blood). The induced ischaemia was studied by BP and PCO2 monitoring, CBF measurement, videomicroscopy of surface cerebral vessels, and finally macroscopic and microscopic examination of brain sections. In group C (8 animals)-moderate degree of CI-brain circulation improved in all animals after the application of the ECCC, installed at 135 min after the onset of CI. In 10 animals (group D) with severe and prolonged (225 min) CI, ECCC enhanced the brain circulation in eight animals to a variable degree.

Animals↗