Biomedical subjects

A Waziri

Publications and source records attributed to A Waziri.

7 recordsLinked to original sources

PubMed2000

Characterization and sequencing of prototypic human T-lymphotropic virus type 1 (HTLV-1) from an HTLV-1/2 seroindeterminate patient.

Serological screening for human T-lymphotropic virus type 1 (HTLV-1) parallels the standard screening process for human immunodeficiency virus (HIV), in which samples found positive by enzyme-linked immunosorbent assay (ELISA) are confirmed with a modified Western blot procedure. There are a significant number of cases in which HTLV-1/2 ELISA-positive specimens demonstrate an incomplete banding pattern on this Western blot. Individuals providing these atypical antibody responses are categorized as seroindeterminate for HTLV-1/2. Although HTLV-1 genomic sequences are readily detectable in the peripheral blood lymphocytes (PBL) of seropositive individuals, previous studies have repeatedly demonstrated that PBL from the vast majority of HTLV-1/2 seroindeterminate individuals are PCR negative for HTLV-1. As a result, identification of the agent responsible for this indeterminate reactivity has been of interest. We have generated an HTLV-1-positive B-cell line (SI-1 B) from one of these seroindeterminate individuals. Previous screening for HTLV-1 in PBL from this patient had been routinely negative by primary PCR; however, HTLV-1 tax had been periodically detected by nested PCR. DNA sequence data generated with genomic DNA from the SI-1 B cell line and HTLV-1-specific primers demonstrated the presence of a full-length viral genome with >97% homology to the Cosmopolitan form of HTLV-1. A 12-bp deletion was identified in the 3'-gag/5'-prot region, which would predict translation of altered or nonfunctional proteins from these genes. We propose that this HTLV-1/2-seroindeterminate patient is infected with a prototypic form of HTLV-1 at an extremely low viral load and that this finding may explain HTLV-1/2 seroindeterminate reactivity in at least a subset of these individuals.

Antibodies, Viral↗

PubMed1999

HTLV-I/II seroindeterminate Western blot reactivity in a cohort of patients with neurological disease.

The human T-cell lymphotropic virus type I (HTLV-I) is associated with a chronic, progressive neurological disease known as HTLV-I-associated myelopathy/tropical spastic paraparesis. Screening for HTLV-I involves the detection of virus-specific serum antibodies by EIA and confirmation by Western blot. HTLV-I/II seroindeterminate Western blot patterns have been described worldwide. However, the significance of this blot pattern is unclear. We identified 8 patients with neurological disease and an HTLV-I/II seroindeterminate Western blot pattern, none of whom demonstrated increased spontaneous proliferation and HTLV-I-specific cytotoxic T lymphocyte activity. However, HTLV-I tax sequence was amplified from the peripheral blood lymphocytes of 4 of them. These data suggest that patients with chronic progressive neurological disease and HTLV-I/II Western blot seroindeterminate reactivity may harbor either defective HTLV-I, novel retrovirus with partial homology to HTLV-I, or HTLV-I in low copy number.

Adult↗

PubMed1998

Implicit and explicit learning in an auditory serial reaction time task.

OBJECTIVE: To explore the role of the motor cortex during implicit and explicit learning. MATERIALS AND METHODS: EEG signals were recorded from 30 channels by measuring task-related desynchronization (TRD) when 10 right-handed naive volunteers performed a variation of the serial reaction task. Stimuli, consisting of 4 pure tones of 500, 1000, 1500, and 2000 HZ, lasting 200 ms, were presented binaurally through a pair of tubephones at 60 dB with a 2-s constant interstimulus interval. A series of 10 repetitive tones represented the test sequence; the random sequence was the control. RESULTS: All subjects developed implicit and explicit knowledge reflected by decreased response time, increased accuracy, and the ability to generate the sequence. Six of 10 subjects demonstrated implicit learning without explicit learning during the first 3 blocks. When subjects acquired full explicit learning, 10 Hz TRD at C3 reached a peak amplitude, declining thereafter. CONCLUSIONS: Properties of the sensorimotor cortex change during learning and these changes are independent of stimulus modality.

Adult↗

PubMed1997

Stereotactic neurosurgery planning with 3-D spiral CT-angiography.

OBJECTIVE: To assess the feasibility and value of spiral CT angiography of the brain vessels for the planning of neurosurgical stereotactic interventions. MATERIAL AND METHODS: Fourty-two patients harboring cerebral lesions underwent spiral CT angiography prior to stereotactic biopsy. Thin spiral CT slices with a collimator slice thickness of 1 mm and a pitch of 1 were used. Multiplanar reconstructions and maximum intensity projections (MIP) were obtained as well as 3-D tissue definition. RESULTS: There was a sufficient visualization of vessels and of their relationship to the lesion. Tumor neovascularization was clearly demonstrated. Arteries could be shown separately. Stereotactic coordinates of targets were chosen at a safe distance from the vessels and the simulation of tarjectories using the cine loop was made possible. In three cases the presence of a pathological vascularization warned against a stereotactic biopsy. CONCLUSION: Spiral CT angiography seems to yield enough topographical information for the accurate planning of stereotactic surgery for brain lesions. CT angiography with the helical technique is rapid and less invasive than digital subtraction angiography.

Adolescent↗

PubMed1996

[Value of CT-angiography in diagnosis of cerebral sinus and venous thromboses].

Dural sinus thrombosis is not uncommon. Due to the nonspecific symptomatology, as well as the manifold etiology, clinical diagnosis may be difficult. In these cases imaging procedures are frequently crucial in deciding how to proceed and how to treat. The aim of our study was to evaluate the diagnostic utility of helical CT in the detection of dural sinus thrombosis. In 20 patients with clinically suspected thrombosis CT angiography was performed. In 6 patients dural sinus thrombosis was diagnosed. In order to acquire also arterial vessels, a short delay of about 22 s after the onset of the application of contrast medium was selected. By this method we found an occlusion of the MCA in two patients with clinically suspected sinus thrombosis. In all patients the transverse slices and the multiplanar reconstructions showed filling defects or an "empty delta" sign. With irregular outlines the thrombus could be depicted over the complete course of the sinus. The MIP reconstructions were particularly helpful in the evaluation of the vessel anatomy and the pathological collateral venous drainage. In three patients MR angiograms were available for comparison. The smaller veins, such as the v. vermis inferior, were less clearly depicted than in CT angiography. CT angiography is a fast and reliable method to exclude or verify a sinus thrombosis. It can be performed immediately after non-enhanced CT. According to our present experience CT angiography is sufficient for the diagnosis of a sinus thrombosis.

Adolescent↗

PubMed1996

[CT-angiography in planning stereotaxic biopsies].

Twenty-one patients referred for stereotactic biopsy were studied by CT angiography. Helical CT with 1 mm collimation was obtained (pitch of 1:1). Multiplanar reconstructions were performed; maximum intensity projections and shaded-surface displays were generated by connectivity-based editing tools. The visualization of cerebral vessels was excellent. No further conventional angiography was needed. Improved information was obtained about localization of the intracranial lesion and its relationship to neighboring vessels. No bleeding complications were detected by CT after stereotactic biopsy.

Adult↗

PubMed1995

Low-dose radiotherapy for stage I seminoma: early results.

One hundred and one patients with stage I seminoma were irradiated with total doses of 30, 25.5 and 20 Gy to gradually reduced target volumes (paraaortic, pelvic, and inguinal regions to paraaortic only). Low doses and small target volumes resulted in excellent survival and freedom of recurrence but in more frequent nausea.

Adult↗