Search PubMed⌕ Search

Biomedical subjects

P Pantazopoulos

Publications and source records attributed to P Pantazopoulos.

At least 19 recordsLinked to original sources
PubMed2006

Survey of breakfast and infant cereals for aflatoxins B1, B2, G1 and G2.

Three hundred and forty-nine breakfast and infant cereal samples were collected at retail level across Canada from 2002 to 2005. They included rice-, soy-, barley-based and mixed-grain infant cereals, corn-, wheat-, rice-based and mixed-grain breakfast cereals, and were analysed for aflatoxins B1, B2, G1 and G2 using a modified AOAC International official method. An immunoaffinity column was used for the cleanup and purification of extracts. Determination of aflatoxins was by LC using post-column derivatization with pyridinium hydrobromide perbromide and fluorescence detection. Results indicated that 50% of both breakfast and infant cereals had detectable levels (limit of detection = 0.002 ng g-1) of aflatoxin B1, which is the most toxic of the four toxins. The levels found varied from 0.002 to 1.00 ng g-1 for aflatoxin B1, from 0.002 to 0.14 ng g-1 for aflatoxin B2, from 0.008 to 0.27 ng g-1 for aflatoxin G1, and from 0.008 to 0.048 ng g-1 for aflatoxin G2. Only 4% of the breakfast cereals and 1% of the infant cereals had aflatoxin B1 levels exceeding 0.1 ng g-1, which is the European Union maximum limit for aflatoxin B1 in baby foods and processed cereal-based foods for infants and young children.

Aflatoxin B1↗
PubMed2005

Infralimbic cortex activation increases c-Fos expression in intercalated neurons of the amygdala.

Recently, it was reported that stimulation of the infralimbic cortex produces a feedforward inhibition of central amygdala neurons. The interest of this observation comes from the fact that the central nucleus is the main output station of the amygdala for conditioned fear responses and evidence that the infralimbic cortex plays a critical role in the extinction of conditioned fear. However, the identity of the neurons mediating this infralimbic-evoked inhibition of the central nucleus remains unknown. Likely candidates are intercalated amygdala neurons. Indeed, these cells receive glutamatergic afferents from the infralimbic cortex, use GABA as a transmitter, and project to the central amygdala. Thus, the present study was undertaken to test whether, in adult rats, the infralimbic cortex can affect the activity of intercalated neurons. To this end, disinhibition of the infralimbic cortex was induced by local infusion of the non-competitive GABA-A receptor antagonist picrotoxin. Subsequently, neuronal activation was determined bilaterally within the amygdala using induction of the immediate early gene Fos. Infralimbic disinhibition produced a significant increase in the number of Fos-immunoreactive intercalated cells bilaterally whereas no change was detected in the central nucleus. In the basolateral amygdaloid complex, increases in the number of Fos-immunoreactive cells only reached significance in the contralateral lateral nucleus. These results suggest that glutamatergic inputs from the infralimbic cortex directly activate intercalated neurons. Thus, our findings raise the possibility that the infralimbic cortex inhibits conditioned fear via the excitation of intercalated cells and the consequent inhibition of central amygdala neurons.

Amygdala↗
PubMed2005

Survey of aflatoxins in beer sold in Canada.

Between March 1998 and March 2002, 304 samples of domestic (Canadian) and imported beers from 36 countries were picked up for the determination of aflatoxins B1, B2, G1 and G2. Twelve samples were positive with aflatoxins greater than the limit of quantitation (LOQ) (aflatoxin B1, 4.4 ng l(-1); aflatoxin B2, 3.4 ng l(-1); aflatoxin G1, 11.2 ng l(-1); and aflatoxin G2, 6.2 ng l(-1)). Five samples from Mexico, two samples from Spain and one from Portugal contained aflatoxin B1. Four samples from India contained aflatoxins B1 and B2. The remaining samples contained less than the LOQ for aflatoxins B1, B2, G1 and G2. The analytical method for this survey was based on that of Scott and Lawrence (Scott PM, Lawrence GA. 1997. Determination of aflatoxins in beer. Journal of AOAC International 80:1229-1234.). Aflatoxins B1, B2, G1 and G2 were determined at parts per trillion (ng l(-1)) levels in beer by immunoaffinity column cleanup followed by derivatization with trifluoroacetic acid and reversed-phase liquid chromatography with fluorescence detection.

Aflatoxin B1↗
PubMed2004

Ochratoxin A in wine and grape juice sold in Canada.

Ochratoxin A (OTA) was determined in 251 samples of wines and grape juice collected over 3 years in Canada. In total, 25/84 samples of red wine, 22/96 samples of white wine, 3/46 red grape juices and 1/25 white grape juices contained OTA levels above the limit of quantitation (LOQ). Canadian wines, when compared with imported products, showed both a lower OTA occurrence, noted as positive (19 versus 48% above the limit of detection (LOD) for wines), and a lower level of OTA contamination (upper bound mean of 17.5 versus 163pg ml(-1) for wines). Wines from the USA contained no quantifiable levels of ochratoxin A. OTA was found in Canadian and US grape juice samples, with 12.9% above the LOD and an upper bound mean of 13.3pg ml(-1). It was extracted from a wine or grape juice sample by passing it through an immunoaffinity column. The sample matrix was washed off the column with water. OTA was eluted from the column with methanol and quantitatively determined by liquid chromatography using a fluorescence detector. The presence of OTA was confirmed by esterification with boron trifluoride-methanol. The LOQ of OTA was estimated as 20 pg ml(-1) in white wine (S/N 10:1) and 40 pg ml(-1) in red wine, white grape juice and red grape juice (S/N 20.1). The LOD was estimated as 4pgml(-1) for white wine and 8pgml(-1) for red wine and white and red grape juices (S/N 3:1).

Beverages↗
PubMed1982

HLA antigens and otosclerosis. A possible new genetic factor.

The pattern of HLA antigens was studied in 68 Greek patients with otosclerosis with and without a family history of otosclerosis and in the members of seven families in which the disease occurs, and was compared with that of 400 unrelated control subjects. Fifty-six specific HLA antiserum samples were used to determine 27 HLA-A and B antigens with the two-stage standard National Institutes of Health assay. The results were modified as follows: There was a highly significant increase of the antigens HLA-A11, Bw35, and B14 only in the patients with family history. These findings, together with the observations from the family studies and the information of population epidemiology and HL distribution frequencies, indicate the possible role of HLA antigens in otosclerosis and corroborate the view that genetic factors are also involved.

Adolescent↗
PubMed1980

Ectopic thyroid gland in the submandibular region.

A rare case of an ectopic thyroid gland appearing as a submandibular mass in a 30-year-old female patient is presented. Special emphasis is placed on the origin, unusual location, functioning status, pathology and diagnostic problems created by this interesting case.

Adult↗
PubMed1978

[Hearing loss and hyperthyroidism (author's transl)].

The audiometric findings on 23 patients with diquited hypothyroidism for a minimum of 4 months to a maximum of 20 years are presented. Audiometric tests, including acustic impedance measurements (tympanometry, stapedius reflex) were performed on all patients before and after an adequate substitution therapy. In 12 patients there was a definite impairment of hearing before the substitution therapy. Eight of them have shown a mild to moderate sensory-neural deafness. Four showed a mixed deafness, in three of which a negative pressure of 300 mm H2O was measured in the middle ear, the fourth one had a seromucotympanon. In three patients with pure sensory-neural deafness the stapedius reflex was elicitated only 30 dB over the pure tone threshold in speech frequencies. The audiometric measurements after an adequate substitution therapy of minimum 4 months has shown a definite improvement of hearing loss.

Acoustic Impedance Tests↗
PubMed1978

Granular cell myoblastoma of the larynx.

Two cases of granular cell myoblastoma of the larynx are presented. In the first case the tumour was excised by laryngofissure, and in the second case by microlaryngoscopy. Based on this experience a review of this interesting tumour is made, and emphasis is given to the fact that this neoplasm may be mistaken for squamous cell carcinoma.

Adult↗
PubMed1978

A schwannoma of the parotid gland. Report of a case.

An unusual case of multiple schwannomas of the parotid gland in a 44-year-old male is presented, and the natural history of the disease is discussed. Neural tumours of the salivary glands are rare, and the treatment of choice is surgery. Recurrence seems to be unusual unless the excision is incomplete.

Adult↗
PubMed1978

57Co-bleomycin imaging study of tumors of the head and neck.

57Co-Bleomycin (57Co-BLM) was used to visualize malignancies of the head and neck because it does not present the disadvantages of many other radiopharmaceuticals. In a series of 21 patients with 9 control subjects and 12 cases of tumors. 57Co-BLM showed a high and rapid uptake in primary site and metastases of malignant tumors of various histologic types, but not in benign tumors such as angiofibromas. Compared to 67Ga-citrate. 57Co-BLM has many advantages for tumor imaging in the areas of nose, pharynx and larynx: No background activity due to the concentration of 57Co-BLM in normal structures of the head and neck has ever been observed, as opposed to what happens with 67Ga-citrate. Furthermore, the blood clearance of 57Co-BLM is much more rapid than that of 67Ga-citrate, so that an early study may be performed in a 6-24 hr. interval instead of 48-72 hr. with 67Ga-citrate. 57Co-BLM scintigraphy is an easy, non-invasive and sensible diagnostic technique in determining the extent of malignant tumors in ORL patients.

Bleomycin↗