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Biomedical subjects

D Pappas

Publications and source records attributed to D Pappas.

At least 19 recordsLinked to original sources
PubMed2006

Akinetic mutism followed by a manic reaction on introduction of steroid replacement for Addison's disease.

Neuropsychiatric changes during exogenous corticosteroid administration are well-recognized. However, reports of neuropsychiatric reactions to corticosteroid replacement for Addison's disease are distinctively rare. We report on a patient with primary adrenocortical insufficiency, initially presenting with depressive symptoms, who developed akinetic mutism followed by acute manic illness shortly after the initiation of steroid replacement. Both disorders occurred with physiological doses of hydrocortisone and resolved spontaneously. The pathogenesis of the above neuropsychiatric reactions is discussed in the context of glucocorticoid receptor-related brain effects of glucocorticoids. In addition, this report points to the need for accurate psychiatric assessment of patients with Addison's disease upon introduction of replacement therapy.

Addison Disease↗
PubMed2003

Support vector machines based analysis of brain SPECT images for determining cerebral abnormalities in asymptomatic diabetic patients.

PURPOSE: An image processing method was developed to investigate whether brain SPECT images of patients with diabetes mellitus type II (DMII) and no brain damage differ from those of normal subjects. MATERIALS AND METHODS: Twenty-five DMII patients and eight healthy volunteers underwent brain 99mTc-Bicisate SPECT examination. A semi-automatic method, allowing for physician's interaction, was developed to delineate specific brain regions (ROIs) on the SPECT images. Twenty-eight features from the grey-level histogram and the spatial-dependence matrix were computed from numerous small image-samples collected from each specific ROI. Classification into 'diabetics' and 'non-diabetics' was performed for each ROI separately. The classical least squares-minimum distance (LSMD) classifier and the recently developed support vector machines (SVM) classifier were used. System performance was evaluated by means of the leave-one-out method; one sample was left out, the classifier was trained by the rest of the samples, and the left-out sample was classified. By repeating for all samples, the classifier's performance could be tested on data not incorporated in its design. RESULTS: Highest classification accuracies (LSMD: 97.8%, SVM: 99.1%) were achieved at the right occipital lobule employing two features, the standard deviation and entropy. For the rest of the ROIs classification accuracies ranged between 84.5 and 98.6%. CONCLUSION: Our findings indicate cerebral blood flow disruption in patients with DMII. The proposed system may assist physicians in evaluating cerebral blood flow in patients with DMII undergoing brain SPECT.

Adult↗
PubMed2001

Time-related decay of the benefits of biofeedback therapy.

Although immediate results are good to excellent in great majority of patients who undergo biofeedback treatment (BFT) for chronic constipation and fecal incontinence, they tend to loose the benefit over a period of time. The purpose of this study was to evaluate the long-term sustainability of results after successful biofeedback treatment. Two groups of patients who successfully completed BFT at our institution from 1995 to 1997 were created based on the date of completion. The first had a mean follow-up of 35 months and the second group was followed for an average of 12 months. Both groups were questioned as to the presence of constipation and incontinence. The questioning was focused depending on the patient's diagnosis. This information was then compared with the initial BFT results. Overall, all patients were satisfied by the initial BFT results. All patients initially had an excellent or good response to BFT. However, after a mean of 35 months, in the first group, 19 of 22 patients had a near complete regression back to their pre-biofeedback status. In the 14 patients in the second group with mean follow-up of 12 months, 11 had a significant decay in benefits. Only time was a significant factor in the decay of BFT benefits. In conclusion, BFT is highly effective in the treatment of selected patients with complex defecation disorders. Although there is a high initial success rate, there is a clear loss of the immediate benefits over time. Other factors such as dietary habits, pelvic floor exercises, manometry, invasive EMG, and rectal sensation did not correlate with long-term outcomes. The comparison between the two groups reveals a linear model describing the time decay of the benefits of BFT. Based on the linear model, patients may need reevaluation after one year and may benefit from additional BFT.

Adult↗
PubMed1999

Selective patching in carotid endarterectomy: is patching always necessary?

BACKGROUND: The value of carotid patching in carotid endarterectomy in achieving low perioperative morbidity and long-term freedom from restenosis is controversial. We hypothesized that if large internal carotid arteries were closed primarily and smaller arteries selectively patched, there would be no difference in early or long-term results between the two groups. METHODS: A retrospective analysis of 133 carotid endarterectomies performed by one surgeon in a community teaching hospital was performed to evaluate a selective approach to patching vs primary closure. Primary closure was performed if the arteriotomy could be closed without tension over a Javid shunt. Seventy-seven arteries underwent primary closure and 56 underwent patching (Vein-14, PTFE-17, Dacron-25). Postoperative (>6 month) duplex scans were available on 46/77 (60%) patients undergoing primary closure, and 33/56 (59%) of patients with patch repair. RESULTS: There were 2 perioperative neurologic deficits, both in the patch group. Restenosis of equal or greater than 50% at 11 months occurred in 5/46 (10.8%) of patients with primary closure and 2/34 patients (5.9%) with patch closure (p=ns). No patient in either group had a late neurologic event or required a redo operation. CONCLUSIONS: Selective primary closure is not associated with increased risk of perioperative neurologic events or statistically significant evidence of late postoperative stenosis if primary closure is performed in large internal carotid arteries.

Aged↗
PubMed1998

Obsessions and compulsions as a distinct cluster of symptoms in schizophrenia: a neuropsychological study.

Using neurocognitive testing, the present study assessed whether obsessions and compulsions could represent a distinct cluster of symptoms in schizophrenia. We formulated our hypothesis based on data from nonschizophrenic patients, expecting to find that schizophrenic patients with obsessive-compulsive (OC) symptoms would experience more difficulties in the same cognitive areas as nonschizophrenic patients with obsessive-compulsive disorder (OCD). Patients had separate psychiatric and cognitive evaluations. The OC and non-OC schizophrenic subjects did not differ significantly on the positive and negative symptom scores. However, compared with non-OC schizophrenic patients, those with OC symptoms performed worse on cognitive areas thought to be impaired (i.e., visual-spatial skills, delayed nonverbal memory, and cognitive shifting abilities). In addition, the severity of OC scores correlated with poor performance in these areas of cognition. Our results support our hypothesis, specifically that OC symptoms may constitute a distinct cluster separate from psychosis in schizophrenia and raise the possibility of a distinct subtype of schizophrenia. The theoretical and clinical implications of these findings are discussed.

Cognition Disorders↗
PubMed1998

Facial nerve outcome in lateral skull base surgery for benign lesions.

OBJECTIVE: To statistically identify factors most important in affecting CN7 outcome in lateral skull base surgery for benign lesions. STUDY DESIGN: A retrospective review of 217 nonmalignancy lateral skull base procedures from 1970 to 1995 at the Otology Group in Nashville. METHODS: Charts were reviewed for epidemiology, histopathology, staging, type of CN7 mobilization (none, short, long, severance with reanastomosis, and resection), preoperative and postoperative CN7 function, surgery performed, and survival. RESULTS: Average House-Brackman (HB) scores for mobilizations were as follows: short, 1.65: long, 2.74: and grafting, 4.33. Factors found to affect outcome in a statistically significant fashion were preoperative HB score, staging, type of CN7 manipulation, and surgical approach. Meningiomas were found to have a worse outcome than glomus tumors. CONCLUSIONS: Complete resection of tumors should be performed with minimal manipulation of the facial nerve based on regional anatomy and tumor anatomy.

Adolescent↗
PubMed1998

Temporal bone and lateral skull base malignancy: experience and results with 81 patients.

OBJECTIVE: This study aimed to examine predictive factors and treatment outcome and to devise a staging method for malignant lateral skull base disease. STUDY DESIGN: The study design was a retrospective review of all lateral skull base surgery cases. SETTING: The study was conducted at a tertiary referral center. PATIENTS: Of 317 lateral skull base lesions, 81 patients were found to have malignant disease. Three groups were identified, and the data were analyzed according to the following: epithelial malignancies, 30 patients; malignancies of salivary gland origin, 23 patients; and malignancies of mesenchymal origin, 28 patients. The mean age was 48.5 years with a range of 5-83 years. There were 42 males and 39 females. Our mean follow-up time was 54 months with a range of 1-180 months. Forty-three patients were alive without evidence of recurrent disease, 6 were living with disease, 25 were dead of disease, 3 died of other causes, and 4 were lost to follow-up. INTERVENTIONS: All patients underwent surgery with curative intent. Forty-two received adjuvant radiation, and 8 received chemotherapy. MAIN OUTCOME MEASURES: Treatment failure, survival, cranial nerve deficits, complications, and predictive factors were analyzed. RESULTS: A 58% treatment success rate was observed. Epithelial and salivary malignancy had a poorer prognosis, and pain and facial nerve dysfunction at presentation carried a worse prognosis. CONCLUSIONS: Lateral skull base malignancy is a rare entity that continues to challenge cranial base surgeons. Cranial nerve deficits and complications are frequent. The success rate of treatment is dependent on histology and disease extent.

Adolescent↗
PubMed1997

Differential relationships between positive and negative symptoms and neuropsychological deficits in schizophrenia.

UNLABELLED: This study assessed the relationships between positive and negative clinical symptoms and specific neuropsychological deficits in a group of stable schizophrenic patients. METHOD: Thirty patients were assessed using the Positive and Negative Syndrome Scale (PANSS) for schizophrenia and a battery of cognitive tests. The PANSS assessments were done by a group of raters blind to the results of cognitive tests, while the cognitive tests were conducted by a different group of raters who remained blind to the PANSS scores. RESULTS: We found that, although positive and negative symptoms showed a trend toward direct correlation with each other, they correlated with distinct cognitive deficits. Patients with higher negative scores had more perseverative responses, perservative errors, and completed fewer categories on the Wisconsin Card Sorting Test; they also experienced more difficulties on trail making and verbal fluency tests. On the other hand, positive symptoms were associated with poor performance on the Digit Span, particularly the Digit Span Forward. CONCLUSIONS: Our findings are in agreement with previous reports that negative symptoms may be associated with poor performance on cognitive tests reflecting particularly frontal function. Positive symptoms, on the other hand, seem to be associated with poor attention, specifically of auditory type, and thus, possibly with dysfunction within the more widespread neural networks underlying attention. Our findings support the hypothesis that positive and negative symptoms may be associated with distinct neuropsychological deficits and thus with distinct neurological substrates and point to the need to address both positive and negative dimensions when studying schizophrenia.

Adult↗
PubMed1997

Lateral skull base surgery: the otology group experience.

Lateral skull base surgery has remained the surgical frontier of new developments in the treatment of lesions heretofore difficult to access. Examination of surgical results stimulates technical innovation and provides an intervention risk-benefit ratio assessment for particular lesions useful in management planning. With this in mind, we report the updated collective experience with lateral skull base surgery at the Otology Group over the past 20 years. Two hundred ninety-eight patients underwent surgical intervention for lateral skull base lesions. In 81 patients these lesions were malignant; in 217, benign. Of the benign lesions, 165 were glomus tumors: 139 glomus jugulare, 19 glomus vagale, and 7 glomus tympanicum. The remainder comprised 21 menigniomas, 14 neuromas, two neurofibromas, and a small group of much rarer entities. The philosophy of surgical approach, results, and follow-up are discussed.

Journal Article↗
PubMed1993

Serum total IgE levels in a representative sample of a Greek population. I. Correlation with age, sex, and skin reactivity to common aeroallergens.

The distribution of IgE in a large randomly stratified Greek population sample was determined in 1187 subjects (793 men and 394 women) aged between 20 and 60 years. Skin prick testing was performed and serum total IgE expressed in iu/ml was measured by Phadebas PRIST: the data are presented as the geometric mean. Subjects were classified as atopic (257 men, 118 women) and nonatopic (536 men, 276 women) according to the results of skin testing with various aeroallergens. At any age, atopic males (120.5 vs 38 iu/ml) and females (99.8 vs 29.3 iu/ml) had higher mean IgE levels, as compared to nonatopic subjects (P < 0.0001). In our adult nonatopic sample, IgE levels did not differ with age (P > 0.05). At any age, nonatopic males had higher (38 iu/ml) mean IgE levels than nonatopic females (29.3 iu/ml) (P < 0.05). The comparison of normal IgE values (nonatopic subjects) from this study with those reported by other investigators revealed that Greek adult males and females had higher IgE levels than populations from other nations. Our results represent the first report on reference values regarding serum total IgE in Greek adults.

Adult↗
PubMed1988

Experimental increase in brain HIPDM uptake by hypercapnia.

The 30-min brain uptake of [125I]HIPDM was measured in conscious rats--normocapnic (n = 8), hypercapnic (n = 12), and hyperoxic (n = 6). A mean 41.2% higher uptake was found in the brains of hypercapnic animals (p less than 0.01). In the three groups of rats, brain HIPDM uptake had a negative correlation with body weight (p less than 0.001) and a positive correlation with arterial pCO2 (p less than 0.01), when adjusted for body weight. These results indicate that HIPDM uptake with hypercapnia may be used as a provocative test to measure cerebral blood flow reserves.

Animals↗