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Biomedical subjects

C Alexiou

Publications and source records attributed to C Alexiou.

52 records · Page 3Linked to original sources
PubMed1998

Primary angiosarcomas of the chest wall and pleura.

Primary angiosarcomas of the chest wall and pleura are extremely rare and carry a dismal prognosis. Two cases are reported. One patient (case 1), presented with massive recurrent haemothorax, was found to have multifocal angiosarcoma of the pleura, treated with surgical de-bulking, chemical pleurodesis and chemotherapy, achieving control of the bleeding. She died 10 months later from complications related to chemotherapy. A full post-mortem examination confirmed this was a primary pleural angiosarcoma with no evidence of disease elsewhere. Another patient (case 2) with a large solitary angiosarcoma of the chest wall, discovered incidentally on a routine physical examination, was successfully treated with surgical excision and subsequent radical radiotherapy, remaining well 15 years post-operatively.

Adult↗
PubMed1998

Chylothorax following oesophagogastrectomy for malignant disease.

OBJECTIVE: To define the incidence, causes, management and impact of Chylothorax after oesophagogastrectomy for malignant disease in Nottingham Thoracic Surgery unit. PATIENTS AND METHODS: Retrospective analysis of 523 patients with cancer of the oesophagus or the gastro-oesophageal junction who underwent oesophageal resection between January 1987 and November 1997 in a single unit using similar techniques and uniform routine perioperative management. RESULTS: Chylothorax occurred in 21 patients (4.0%). There were 12 males and 9 females with a mean age of 64.7 years (SD 7.5). Age, sex, tumour site, length, histological type, depth of wall penetration, nodal status and type of operative approach were not significant predisposing factors on univariate and multivariate analysis. Seventeen patients were treated conservatively (four deaths, 23.5%) and four surgically (one death, 25.0%), effective control of the chylous leak being achieved in all four cases. Eleven patients with a chylous drainage of up to 2.2 l/day, diminishing within 1 week of conservative treatment had an uneventful recovery. However, a chylous drainage of more than 2.5 l/day in the remaining ten patients was associated with increased morbidity, hospital stay, operative mortality and the need for surgical intervention. In comparison with the remaining patients (n = 502), those who developed chylothorax (n = 21) had more respiratory complications (42.8%, P = 0.008), longer mean hospital stay (23.8 days, P = 0.004), higher operative mortality (23.1%, P = 0.004) and, unexpectedly, reduced 5 year survival rate (P < 0.0001). CONCLUSIONS: There appeared to be no clear predisposing factor in the development of a chylous leak other than the routine extensive dissection. Although definitive conclusions can not be drawn, where there is early reduction of the initial amount (in this series up to 2.2 l/day) of drainage, there may be a place for successful non-surgical management; in cases of high output chylothorax, persisting after a few days of conservative treatment, however, early re-operation and ligation of the thoracic duct, seems to be advisable.

Aged↗
PubMed1997

[Occlusion of an esophagobronchial fistula by implantation of a Montgomery esophageal and a dynamic tracheal stent after failure of conventional endoprosthesis].

Esophagorespiratory fistulas were frequently caused by malignant tumors, bougienage, laser therapy or radiochemotherapy. We here report the case of a patient with inoperable bronchial cancer, who developed a symptomatic esophagorespiratory fistula during combined radiochemotherapy with Cisplatin. A sufficient occlusion of the fistula could not be achieved with conventional plastic tubes or novel self-expanding silicone-coated Gianturco Song stents. After extraction of two Gianturco Song stents we inserted a Montgomery Salivary Bypass Stent into the esophagus and Dynamic stent into the trachea. This resulted in a total occlusion of the fistula. This present case suggests that the Montgomery stent may have little tendency to migrate due to its characteristic configuration and fixation and further demonstrates that the novel self-expanding silicone-coated Gianturco Song stents can be removed, if necessary.

Adenocarcinoma↗
PubMed1993

Effect of bombesin antagonist D-Phe6-BN(6-13)OMe on vagally induced gastrin release from perfused rat stomach.

The aim of the present study was to evaluate the effect of the bombesin antagonist D-Phe6-BN(6-13)OMe (BN-antagonist) on vagally stimulated gastrin release from the isolated rat stomach, which was perfused via the celiac artery with Krebs-Ringer buffer. Vagal stimulation was performed for 10 minutes with 1 ms, 10 V and 10 or 2 Hz, respectively. Gastrin secretion increased significantly during stimulation with 10 and 2 Hz. BN-antagonist was added to the perfusate at the concentration of 10(-6) M, which induced a significant reduction of vagally stimulated gastrin release at 10 Hz (619 +/- 65 vs. 252 +/- 62 pg/10 min, p < 0.05), but not at 2 Hz (564 +/- 117 vs. 493 +/- 113 pg/10 min, p > 0.05). In contrast, atropine (10(-7) M) reduced significantly the gastrin response at 2 Hz (270 +/- 78 pg/10 min, p < 0.01), but not at 10 Hz (446 +/- 87 pg/10 min, p > 0.05). The combination of BN-antagonist and atropine elicited an inhibition of vagally stimulated gastrin release similar to each substance when given alone. Basal gastrin release was not changed by the BN-antagonist. The present data suggest, that in the rat stomach endogenously released bombesin-related peptides contribute to the noncholinergic stimulation of gastrin release at higher stimulation frequencies (10 Hz), however, bombesin-related peptides are not involved, when lower stimulation frequencies (2 Hz) are employed. At both stimulation frequencies additional mechanisms are activated which are noncholinergic and not related to bombesin peptides.

Animals↗
PubMed1987

Recombinant human erythropoietin therapy in haemodialysis patients--dose determination and clinical experience.

Recombinant human erythropoietin (R-Hu-EPO) was given to stable, long-term haemodialysis patients with haematocrit less than or equal to 25% who required no blood transfusions. Thirteen patients were initially given R-Hu-EPO at 24 U/kg i.v. at the end of each dialysis session, with a doubling of the dose every second week until a dose of 96 U/kg (n = 6) or 192 U/kg (n = 7) was reached after 8 weeks. In addition, three patients were given 24 U/kg for 2 weeks and subsequently 48 U/kg for 14 weeks. Median haematocrit increased from 19.4% (14.8-24.3) to 30.0% and 32.5% with 96 or 192 U/kg respectively. Starting 7 days after R-Hu-EPO a log dose-dependent increase in reticulocyte counts was noted. A consistent decrease in ferritin concentrations was observed despite oral supplementation of iron. A continuous rise in platelet counts was noted. Irrespective of blood-pressure status, predialysis blood pressure increased in six of nine patients who were not on antihypertensive medication; increased antihypertensive therapy was required in the others. A rise in bilirubin within the normal range was seen at the end of the study. No severe clinical side-effects occurred; specifically, there were no thrombotic episodes with the exception of clotting of two fistulae with known stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Treatment of an esophagorespiratory fistula by insertion of an esophageal Montgomery and tracheal dynamic stent after failure of conventional endoprosthesis.

Esophagorespiratory fistulae at the adult age can develop through malignant tumor growth, endoscopy, bougienage, laser therapy, or through a radiochemotherapy. We report a female patient with inoperable bronchial cancer, who developed a symptomatic esophagorespiratory fistula during radiochemotherapy with cisplatin. At first, conventional plastic tubes and then novel selfexpanding silicone-coated Gianturco-Song stents were used in an unsuccessful attempt to close the fistula. After the extraction of two Gianturco-Song stents, the insertion of a Montgomery-Salivary bypass stent in the esophagus and a dynamic stent in the trachea resulted in a permanent occlusion of the fistula. This case demonstrates that Montgomery-Salivary bypass stents do not tend to migrate due to their characteristic shape and self-fixation, and that the novel self-expanding, silicone coated Gianturco-Song stents can be extracted with rigid endoscopy if necessary.

Adult↗
PubMedDate not supplied

Confirmation of G. von Békésy's theory of paradoxical wave propagation along the cochlear partition by means of bone-conducted auditory brainstem responses.

In order to investigate the propagation time of the traveling wave in the cochlea after bone-conduction stimulation of the inner ear, bone-conducted auditory brainstem responses (ABRs) were recorded in 6 normally hearing subjects after masking the basal cochlear region using high-pass filtered noise. As in air-conducted ABRs, Jewett V wave latency is delayed corresponding to the propagation time of the traveling wave front traversing the desynchronized hair cell region. These results support the theory of paradoxical wave propagation proposed by von Békésy in 1952, who postulated that wave motion always starts from the stiffest part of the basilar membrane, independent of the location of the vibrating force. In addition, we also found a latency delay of the Jewett V wave of bone-conducted ABRs in 8 patients with high-frequency hearing loss which corresponded to the severity of their hearing impairment.

Adolescent↗
PubMedDate not supplied

Diagnostic procedures for detection of lymph node metastases in cancer of the larynx.

Squamous cell carcinoma is the most common malignant neoplasm of the larynx. One of the most important influences on prognosis is the presence of metastases to the cervical lymph nodes. Accurate determination of lymph node involvement is therefore a prerequisite for individualized therapy in patients with squamous cell carcinoma of the larynx. Clinical palpation of the neck is not very accurate and the role of imaging techniques such as ultrasound, ultrasound-guided fine needle aspiration cytology, color Doppler ultrasound, computed tomography, magnetic resonance imaging and positron emission tomography is being applied in order to improve upon the results of clinical investigation alone. According to our investigations and review of the literature, the accuracy of computed tomography scanning (84.9%) and magnetic resonance imaging (85%) was superior to palpation (69.7%) and ultrasound (72.7%). Ultrasound-guided fine needle aspiration cytology showed an accuracy of 89% and was in the same range with positron emission tomography (90.5%).

Biopsy, Needle↗
PubMedDate not supplied

High-resolution three-dimensional magnetic resonance imaging of the vestibular labyrinth in patients with atypical and intractable benign positional vertigo.

Benign paroxysmal positional vertigo (BPPV) is a most common cause of dizziness and usually a self-limited disease, although a small percentage of patients suffer from a permanent form and do not respond to any treatment. This persistent form of BPPV is thought to have a different underlying pathophysiology than the generally accepted canalolithiasis theory. We investigated 5 patients who did not respond to physical treatment, presented with an atypical concomitant nystagmus or both with high-resolution three-dimensional magnetic resonance imaging of the inner ear. This method provides an excellent imaging of the inner ear fluid spaces. In all 5 patients, we found structural changes such as fractures or filling defects in the semicircular canals which we did not find in control groups. One patient clinically presented with the symptoms of a 'heavy cupula'. Whereas crosssections through the ampullary region and the adjoining utricle showed no abnormalities, there were significant structural changes in the semicircular canals, which are able to provide an explanation for the symptoms of a heavy cupula.

Adult↗
PubMedDate not supplied

Medical applications of magnetic nanoparticles.

In recent years biomedical research indicated, that magnetic nanoparticles can be a promising tool for several applications in vitro and in vivo. In medicine many approaches were investigated for diagnosis and therapy and offered a great variety of applications. Magnetic cell separation, magnetic resonance imaging (MRI), magnetic targeted delivery of therapeutics or magnetically induced hyperthermia are approaches of particular clinical relevance. For medical use, especially for in vivo application it is of great importance that these particles do not have any toxic effects or incompatibility with biological organism. Investigations on applicable particles induced a variability of micro- and nanostructures with different materials, sizes, and specific surface chemistry.

Drug Delivery Systems↗
PubMedDate not supplied

Quantification of magnetic nanoparticles by magnetorelaxometry and comparison to histology after magnetic drug targeting.

Magnetic nanoparticles can be used in medicine in vivo as contrast agents and as a drug carrier system for chemotherapeutics. Thus local cancer therapy is performed with Magnetic Drug Targeting (MDT) and allows a specific delivery of therapeutic agents to desired targets, i.e., tumors, by using a chemotherapeutic substance bound to magnetic nanoparticles and focused with an external magnetic field to the tumor after intraarterial application. Important for this therapeutic principle is the distribution of the particles in the whole organism and especially in the tumor. Therefore we used magnetorelaxometry to quantify ferrofluids delivered after MDT. Tissue samples of some mm3 volume of a VX2 squamous cell carcinoma were measured by magnetic relaxation and the amount of iron was determined using the original ferrofluid suspension as a reference. From this the distribution of the magnetic particles within the slice of tumor was reconstructed. Histological cross-sections of the respective tumor offer the opportunity to map quantitatively the particle distribution and the vascularisation in the targeted tumor on a microscopic scale. Our data show that the integral method magnetorelaxometry and microscopic histological methods can complete each other efficiently.

Animals↗
PubMedDate not supplied

Experimental remarks on various types of small vessel anastomoses.

Experiments were carried out on small arteries in dogs with end-to-end anastomosis by conventional sutures. Nakayama's rings and methyl-2-Cyanocrylate adhesive. Problems concerning their application for a satisfactory patency of the vessels are discussed. In conclusion, the best results were observed in the second group, while the use of adhesive material, though promising, is not to be advocated till further development of the material.

Animals↗
PubMedDate not supplied

Experimental remarks after cervical sympathectomy.

The present experimental work was undertaken to determine some quantitative changes occurring after cervical sympathectomy applied for the treatment of Raynaud's diseases. The blood flow in the brachial artery was measured before and after sympathectomy as well as the temperature, haemoglobin concentration and oxyhaemoglobin saturation in arterial and venous blood, pH and PCO2 of the arterial blood.

Animals↗