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Biomedical subjects

A Papanicolaou

Publications and source records attributed to A Papanicolaou.

At least 19 recordsLinked to original sources
PubMed2006

Heliconius wing patterns: an evo-devo model for understanding phenotypic diversity.

Evolutionary Developmental Biology aims for a mechanistic understanding of phenotypic diversity, and present knowledge is largely based on gene expression and interaction patterns from a small number of well-known model organisms. However, our understanding of biological diversification depends on our ability to pinpoint the causes of natural variation at a micro-evolutionary level, and therefore requires the isolation of genetic and developmental variation in a controlled genetic background. The colour patterns of Heliconius butterflies (Nymphalidae: Heliconiinae) provide a rich suite of naturally occurring variants with striking phenotypic diversity and multiple taxonomic levels of variation. Diversification in the genus is well known for its dramatic colour-pattern divergence between races or closely related species, and for Müllerian mimicry convergence between distantly related species, providing a unique system to study the development basis of colour-pattern evolution. A long history of genetic studies has showed that pattern variation is based on allelic combinations at a surprisingly small number of loci, and recent developmental evidence suggests that pattern development in Heliconius is different from the eyespot determination of other butterflies. Fine-scale genetic mapping studies have shown that a shared toolkit of genes is used to produce both convergent and divergent phenotypes. These exciting results and the development of new genomic resources make Heliconius a very promising evo-devo model for the study of adaptive change.

Animals↗
PubMed2003

Do cognitive patterns of brain magnetic activity correlate with hippocampal atrophy in Alzheimer's disease?

BACKGROUND: Many reports support the clinical validity of volumetric MRI measurements in Alzheimer's disease. OBJECTIVE: To integrate functional brain imaging data derived from magnetoencephalography (MEG) and volumetric data in patients with Alzheimer's disease and in age matched controls. METHODS: MEG data were obtained in the context of a probe-letter memory task. Volumetric measurements were obtained for lateral and mesial temporal lobe regions. RESULTS: As expected, Alzheimer's disease patients showed greater hippocampal atrophy than controls bilaterally. MEG derived indices of the degree of activation in left parietal and temporal lobe areas, occurring after 400 ms from stimulus onset, correlated significantly with the relative volume of lateral and mesial temporal regions. In addition, the size of the right hippocampus accounted for a significant portion of the variance in cognitive scores independently of brain activity measures. CONCLUSIONS: These data support the view that there is a relation between hippocampal atrophy and the degree of neurophysiological activity in the left temporal lobe.

Aged↗
PubMed2001

Ambiguous genitalia, 45,X/46,XY mosaic karyotype, and Y chromosome microdeletions in a 17-year-old man.

OBJECTIVE: To describe clinical and laboratory features of a patient with 45,X/46,XY mosaic karyotype and Y chromosome microdeletions and to discuss the diagnostic problems in his management. DESIGN: Case report. SETTING: University department. PATIENT(S): A 17-year-old man with ambiguous genitalia, 45,X/46,XY mosaic karyotype, and Y chromosome microdeletions. INTERVENTION(S): Testicular ultrasonography, karyotype, open testicular biopsy, polymerase chain reaction (PCR) screening for cystic fibrosis, PCR screening for Y chromosome microdeletions in peripheral blood and testicular tissue, and reverse transcriptase PCR in testicular tissue for Y chromosome microdeletions. MAIN OUTCOME MEASURE(S): Avoidance of dissemination of testicular cancer. RESULT(S): The patient was referred for bilateral orchiectomy. CONCLUSION(S): 45,X/46,XY mosaic karyotype is associated with a broad spectrum of phenotypes that includes female with Turner syndrome, male with mixed gonadal dysgenesis, male pseudohermaphroditism, and apparently normal male. Microdeletions of the long arm of the Y chromosome may be associated with Y chromosomal instability, leading to formation of 45,X cell lines. 45,X/46,XY males carry an increased risk for gonadal tumors and must be followed closely.

Adolescent↗
PubMed1998

Epidemiology of onychomycosis in southern Greece.

BACKGROUND: Onychomycosis appears to be a variable entity: it presents in different forms in different parts of the world. It is probable that every country has its own particularities of presentation and it is also probable that different regions of the same country, with either different or equivalent environmental conditions, present with different levels of incidence. Large-scale epidemiological studies performed worldwide have demonstrated different epidemiological results. OBJECTIVE: This study was undertaken to determine the epidemiology of onychomycosis in the population of southern Greece. METHODS: Direct microscopic examination and culture were performed on samples from patients with clinical suspected onychomycosis. RESULTS: The most frequently isolated fungus was Candida (52.44%), followed by dermatophytes (41.04%) and saprophytic molds (6.51%). Finger nails were infected more than toe nails in both sexes. The most frequently isolated fungus in finger nails was Candida (76%), followed by dermatophytes (23%), and molds (1%); toe nails were most often infected by dermatophytes (71%), Candida (13%) and molds (16%). Among the infected women patients, the most frequently isolated fungus was Candida (64%), followed by dermatophytes (30.58%); 5.33% were infected by saprophytic molds. Of the 101 men infected, dermatophytes were most frequently isolated (62.37%), followed by Candida (28.71%) and saprophytic molds (8.91%). CONCLUSIONS: Comparison of the results of epidemiological studies of onychomycosis worldwide show great differences, not only between different countries and different climate zones, but also between studies performed in the same country. In our opinion such epidemiological studies should be performed in every country in order to determine the major fungal species responsible; such information is extremely useful in the treatment of nail onychomycosis.

Adolescent↗
PubMed1997

Identification of side of seizure onset in temporal lobe epilepsy using memory tests in the context of reading deficits.

Sixty patients with temporal lobe epilepsy were classified into reading deficient (RD; n = 21) and non-reading deficient (non-RD; n = 39) groups. Selective deficits in verbal or nonverbal memory, consistent with side of seizure onset, were evident in the non-RD patients. Both verbal and nonverbal memory performance were reduced equivalently in individuals with RD, regardless of side of seizure onset. As a result, memory tests that were accurate in identifying side of seizure onset in the non-RD group were not as accurate in the RD group. When individual cases were classified using a clinically applicable decision rule, significantly more RD patients were either unclassifiable or incorrectly classified than were non-RD patients. Findings suggest that preoperative memory data obtained from individuals with epilepsy and evidence of RD may not be as valid an indicator of side of seizure onset as are those obtained from patients without RD.

Achievement↗
PubMed1997

Asymmetries in the effect of side of seizure onset on recognition memory following intracarotid amobarbital injection.

PURPOSE: To assess interhemispheric differences in recognition memory for objects during the intracarotid amobarbital sodium procedure (IAP). METHODS: The recognition memory for real objects of patients with either right (RTLE; n = 28) or left (LTLE; n = 22) temporal lobe epilepsy was assessed at baseline, and after left and right intracarotid amobarbital sodium injection. RESULTS: There were no differences between groups on baseline performance. Performance following injection ipsilateral to the side of seizure focus was relatively lower for the LTLE as compared with the RTLE group, but this difference did not reach statistical significance. However, performance following injection contralateral to the side of seizure focus was significantly lower for the RTLE as compared with the LTLE group. Within-group differences in performance after ipsilateral as compared with contralateral injection were significant for the RTLE but not the LTLE group. The difference in interhemispheric asymmetry in IAP memory performance between RTLE and LTLE groups was reflected in decreased ability to classify LTLE patients as compared with RTLE patients about side of seizure onset, using a clinically applicable decision rule. CONCLUSIONS: Recognition memory during the IAP for real objects, simultaneously named and presented visually during encoding, is mediated effectively by both the left and right hemisphere when there is no seizure focus present. However, memory appears to be more vulnerable to the presence of a seizure focus in the right as compared with the left hemisphere.

Adolescent↗
PubMed1997

Effects of duration of epilepsy on the uncoupling of metabolism and blood flow in complex partial seizures.

We derived interhemispheric asymmetry indices (AIs) in interictal glucose uptake and blood flow in the temporal lobes of patients with intractable complex partial seizures from 18F and 15O positron emission tomograms. All patients subsequently underwent either left (n = 16) and right (n = 18) temporal lobectomy. We determined the effects on AIs of clinical seizure variables, including duration of seizure disorder, age at seizure onset, frequency of complex partial seizures, history of secondary generalization, history of febrile seizures, and magnetic resonance imaging evidence for mesial temporal sclerosis. Duration of seizure disorder produced the only significant effects. Degree of interhemispheric asymmetry in both glucose uptake and blood flow increased with duration of seizure disorder. However, the rate of increase in asymmetry was significantly greater for glucose uptake than for blood flow. These results indicate that uncoupling of metabolism and blood flow is a progressive process that results from the differential response of glucose metabolism and blood flow to chronic seizure activity. The results also suggest that duration of seizure disorder may be an important variable to consider in the interpretation of PET studies for evaluation of seizure surgery candidates.

Adult↗
PubMed1997

Allotypes and gynecological cancer.

PURPOSE: To investigate if gynecologic cancer patients have different immune responses. METHODS: Immunoglobulin heavy chains (Glm, G3m), Kappa light chains (Km) and allotype and phenotype frequencies were examined in 58 patients with gynecologic cancer (ovarian, cervical, endometrial, vulval, vaginal and uterine sarcoma) and a control group of 26 women. RESULTS: No significant differences were found between the different allotype of phenotype frequencies between the two groups. CONCLUSIONS: Our results indicate that Gm and Km allotypes do not represent susceptibility factors for gynecologic cancer in Caucasians.

Biomarkers↗
PubMed1996

Effects of temporal lobe epilepsy on spatial and figural aspects of memory for a complex geometric figure.

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal sclerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE.

Adult↗
PubMed1996

Memory tests distinguish between patients with focal temporal and extratemporal lobe epilepsy.

We examined the ability of preoperative memory performance to distinguish between patients who had been diagnosed as having left (LTLE, n = 31), right (RTLE, n = 37), and extra-(ETLE, n = 17) temporal lobe focal epilepsy. All patients eventually underwent surgical resections. Analyses indicated that the ETLE group performed better than the RTLE group on nonverbal memory measures and better than the LTLE group on verbal memory measures. Discriminant function analyses indicated that use of a combination of measures that assess different aspects of memory were of significant value in distinguishing between patients with focal TLE and ETLE. This approach, as compared the use of single measures, improved classification rates of all three groups. The best single predictor of group membership, an index of verbal learning, yielded a 47% overall correct classification rate, with sensitivities ranging from 25 to 59%, and performed at worse than chance levels in classifying RTLE patients. A multivariate approach, which included an index of verbal and nonverbal learning, incidental nonverbal memory, and consolidation of organized and rote verbal material, yielded a 65% correct classification rate, with sensitivities ranging from 57 to 75%. This compares favorably with the other noninvasive techniques for lateralizing epileptogenic lesions.

Adolescent↗
PubMed1992

Comparative assessment of proliferating cell nuclear antigen immunostaining and of nucleolar organizer region staining in transitional cell carcinomas of the urinary bladder. Correlation with other conventional prognostic pathologic parameters.

The expression of two cell proliferation indices, the proliferating cell nuclear antigen (PCNA), using the monoclonal antibody PC-10 in the immunoperoxidase method, and the nucleolar organizer regions (NORs), using the colloid silver nitrate staining technique, was assessed in formalin-fixed paraffin-embedded material of 50 transitional cell urinary bladder carcinomas. A relationship was found between the histologic grade and each of the two indices used. A significant difference was observed, particularly between carcinomas of grade II and III (p < 0.001). A relationship was also demonstrated between each of PC-10 and AgNOR scores and the clinical stage, but it was attributed mostly to the close correlation of the latter with the histologic grade of these tumors. The linear correlation coefficient between PC-10 and AgNOR scores was 0.757 (p < 0.001). Our results suggest that PC-10 and AgNOR scores may be important prognostic indices in urinary bladder cancer.

Antigens, Neoplasm↗
PubMedDate not supplied

Can maturation arrest occur at the stage of spermiogenesis?

This article attempts to clarify the pathological condition during which the maturation of the germinal epithelium is unable to evolve beyond a certain stage and is characterized as maturation arrest. Emphasis is given to the histological entity named spermiogenic arrest.

Humans↗
PubMedDate not supplied

Spontaneous pregnancy following therapeutic approach of an infertile man with aspermia/obstructive azoospermia.

The combination of aspermia and obstructive azoospermia in the same infertile man is a rather rare entity. In the case reported here, all diagnostic criteria as well as subsequent recovery following two operations are compatible with an inflammatory origin. In such cases assisted reproduction should be recommended. However, in this case, an early spontaneous pregnancy rendered this unnecessary.

Adult↗
PubMedDate not supplied

Term pregnancy after vaginal transplantation in a case of vaginal agenesis with a functional uterus.

This is a report of a successful pregnancy on a patient that had congenital vaginal aplasia with a functioning uterus. Continuity of the reproductive tract was restored at 12 years of age with transplantation of vaginal wall from the mother. The patient had no problems after initiating intercourse 7 years later and conceived without treatment after 5 years of primary infertility. She was delivered by cesarean section at term.

Child↗