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Biomedical subjects

A Khurshid

Publications and source records attributed to A Khurshid.

13 recordsLinked to original sources
PubMed2000

Auditory habituation in young and older adults: the verbal transformation effect.

In 3 experiments, auditory massed repetition was used to examine age-related differences in habituation by means of the verbal transformation paradigm. Participants heard 10 words (5 high frequency and 5 low frequency), each presented 180 times, and they reported perceived changes in the repeated words (verbal transformations). In these experiments, older adults reported fewer illusory percepts than young adults. Older adults' loss of auditory acuity and slowing of processing, stimulus degradation (in young adults), and instructions biasing the report of these illusory percepts did not account for the fewer illusory percepts reported by the older adults. These findings suggest that older adults' reduced susceptibility to habituation arises from centrally located declines in the transmission of information within the word-recognition pathway. The discussion focuses on the implications that these age-related declines may have on word identification during on-line speech perception.

Adolescent↗
PubMed1999

Wegener's granulomatosis and alpha1-antitrypsin-deficiency emphysema: proteinase-related diseases.

Wegener's granulomatosis (WG) and alpha1-antitrypsin (alpha1-AT)-deficiency emphysema are both uncommon disorders. A relationship may exist between these diseases involving the proteinase and antiproteinase balance in the lung. A case is presented of WG and alpha1-AT-deficiency emphysema occurring in the same patient. Previous studies concerning the correlation between abnormal alpha1-AT alleles and WG are discussed. Potential mechanisms for the relationship and recommendations for screening are given.

Adult↗
PubMed1999

Disseminated Pseudallescheria boydii infection in a nonimmunocompromised host.

We present a highly unusual case of pulmonary Pseudallescheria boydii infection in a nonimmunocompromised host with a cavitating mass lesion. The diagnosis was confirmed by open lung biopsy. The patient was treated at another institution with course of amphotericin B, considered an ineffective therapy for this infection, and presented to us with direct extension and invasion of the left atrial appendage and the pulmonary artery, followed by massive pulmonary embolization and hematogenous dissemination to the liver, spleen, kidney, pancreas, and brain.

Amphotericin B↗
PubMed1999

Meningioma in four patients with human immunodeficiency virus infection.

We describe four patients infected with the human immunodeficiency virus (HIV) who had development of meningiomas. In contrast to those in the general population who have meningiomas, all our patients were young men; the mean age was 40 years (range, 32 to 50). Their risk behavior for HIV was homosexuality (three patients) and intravenous drug use (one patient). The CD4+ cell count in each of the three homosexual men was less than 50/microL and was 280/microL in the drug user. Imaging studies showed enhancing lesions in three of the patients. Although each of these meningiomas could have occurred in otherwise normal young to middle-aged men, we speculate that the meningiomas may have grown in these HIV-infected hosts because of either loss of immune function or dysregulation of cytokines.

Adult↗
PubMed1998

Single-stage, bilateral, video-assisted thoracoscopic lung volume reduction surgery for end-stage emphysema.

The reintroduction of lung volume reduction surgery has provided functional improvement for selected patients afflicted with end-stage emphysema. Evolution of the operation from a median sternotomy approach to the two-stage video-assisted thoracoscopic surgical technique in our experience has resulted in a faster return to full activity. Nineteen patients underwent video-assisted thoracoscopic lung volume reduction surgery between July 1995 and August 1997. The 12 men and 7 women in the study had an average age of 63.7 years. All patients were evaluated preoperatively with computed tomography of the chest, radionuclide lung perfusion scan, left ventricular stress test, right heart catheterization, and a monitored rehabilitation program. In 15 patients the operation was performed as a bilateral single-stage procedure. The operation involved resection of wedges from the upper lobes and in 10 of these patients from the lower lobes as well. In all patients the estimated operative blood loss was less than 150 ml. The mean operative time was 177 minutes (range 115-235 minutes). The mean length of hospital stay was 10.8 days (median 11 days, range 5-24 days). At 2 to 3 months' follow-up increases were noted in the FEV1 (51%), PaO2 (27%), and 6-minute walk distance (18%); and there was a decrease in total lung capacity and respiratory volume. No significant change was observed in carbon monoxide diffusion in the lung. Morbidity included persistent air leaks in three patients and refractory supraventricular tachyarrhythmia in one. There were no perioperative deaths. We therefore recommend this technical modification to reduce operating time and blood loss without compromising surgical exposure or outcome.

Endoscopy↗
PubMed1998

A prospective, controlled study of Helicobacter pylori seroprevalence in coronary artery disease.

OBJECTIVE: Recent studies have suggested that chronic infections may be a risk factor for coronary artery disease. The aim of this study was to determine whether Helicobacter pylori (H. pylori) infection was an independent risk factor for coronary artery disease. METHODS: A total of 179 patients undergoing coronary angiography for suspected coronary artery disease were prospectively studied. Angiograms were read by experienced invasive cardiologists blinded to the results of H. pylori serology, which was determined by a validated multiwell ELISA assay. RESULTS: A total of 121 patients (68%) had evidence of coronary artery disease, whereas 58 patients (32%) had normal coronary angiograms. Of the 121 patients with coronary artery disease, 29 had single vessel disease, 39 had double vessel disease, and 53 had triple vessel disease, respectively. There was no significant difference in seroprevalence of H. pylori infection in patients with and without coronary artery disease (p = 0.63). The odds ratio (after adjustment for other known risk factors) for coronary artery disease in H. pylori-infected subjects was 0.45 (95% CI = 0.15, 1.37; p = 0.107). In patients with coronary artery disease, H. pylori infection did not increase the likelihood of severe disease (odds ratio for triple vessel disease = 0.53; 95% CI 0.18, 1.60; p = 0.201). CONCLUSION: H. pylori infection rates are similar in patients with normal and abnormal coronary arteries, and infection with H. pylori is not an independent risk factor for coronary artery disease. In patients who have coronary artery disease, H. pylori infection is not a risk factor for more severe disease. These data argue against a causal role for H. pylori in the pathogenesis of coronary artery disease.

Adult↗
PubMed1998

Infection of human papillomavirus (HPV) and Epstein-Barr virus (EBV) and p53 expression in human esophageal carcinoma.

To clarify the role of high risk human papillomavirus (HPV 16, 18 and 33) and Epstein-Barr virus (EBV) infection in esophageal carcinogenesis in relation to expression of mutated p53 antioncogene, we used PCR to amplify DNA sequences of these viruses and immunohistochemistry to detect p53 expression in formaline-fixed, paraffin embedded blocks including 12 normal esophageal and 27 esophageal carcinoma specimens. HPV and EBV DNA were found in 25% and 0% of normal esophageal tissues and in 63% and 7% of esophageal carcinoma specimens, respectively. p53 expression was shown in 59% of esophageal carcinoma specimens only. HPV infection rate was significantly higher in specimens from carcinoma cases as compared with normal esophageal tissue obtained from cases without carcinoma. No correlation was found between p53 expression and/or the presence of viral DNA (HPV/EBV) in regard to the age and sex of the patient, histological grade, histological stage, depth of invasion, lymph node involvement, distant metastasis and the location of the tumors, p53 expression was almost equally distributed between HPV positive and negative carcinoma cases. Our results suggest that most of the esophageal carcinomas are associated with HPV infection and p53 mutations and there is no inverse correlation between HPV and infection and expression of p53 in esophageal carcinoma.

Adult↗
PubMed1996

Formulae and tables for the determination of sample sizes and power in clinical trials for testing differences in proportions for the two-sample design: a review.

This paper is a compendium of exact and asymptotic formulae and tables for estimating the sample size in a clinical trial with two treatment groups and a dichotomous outcome. The paper provides separate formulae for equal and unequal treatment group sizes, formulae for the calculation of power given the sample size, and complete references for all formulae and tables cited.

Binomial Distribution↗
PubMed1995

On analysis of epidemiological data involving a 2 x 2 contingency table: an overview of Fisher's exact test and Yates' correction for continuity.

Fisher's exact test and Pearson's chi-square with continuity correction are frequently employed in the analysis of epidemiological data involving a 2 x 2 contingency table. This paper reviews the concepts and controversies underlying these procedures and discusses their appropriateness and adequacies in analyzing such data. Other related procedures such as unconditional exact tests and randomized and mid-p tests including some generalizations to a r x c table are also briefly reviewed.

Biometry↗