Biomedical subjects

Mohamed Omar

Publications and source records attributed to Mohamed Omar.

5 recordsLinked to original sources

PubMed2026

Type 1 interferon perturbates clonal competition by reshaping human blood development.

Inflammation accelerates evolutionary dynamics of hematopoietic stem cells (HSCs) in clonal hematopoiesis and myeloid neoplasms. We studied HSCs, progenitors and immune cells from patients with myeloproliferative neoplasms at baseline and following interferon-α (IFNα) treatment, the only therapy to deplete mutated stem cells. We deployed single-cell multiomics methods that distinguish the IFNα effects on mutated stem cells from the admixed wild-type HSCs, with respect to their differentiation, transcriptomes, immunophenotypes and chromatin accessibility. IFNα simultaneously activated HSCs into two polarized states: a lymphoid progenitor expansion associated with an anti-inflammatory state and an inflammatory myeloid progenitor state derived from HSCs. The augmented lymphoid differentiation balanced the typical myeloproliferative-neoplasm-induced myeloid bias, associated with normalized blood counts. Somatic mutations modified the effects of IFNα on HSC differentiation and cell cycle entry rates. Clonal fitness upon IFNα exposure was due to resistance of CALR- or JAK2-mutated stem cells to differentiate into inflammatory myeloid progenitors.

Journal Article↗

PubMed2006

Pediatric craniopharyngioma--rationale for multimodal management: the Egyptian experience.

BACKGROUND: Situated in a suprasellar location, craniopharyngiomas produce devastating endocrinological manifestations, visual impairment, and raised intracranial pressure, presenting a formidable disease entity for the neurosurgeon as well as the 'craniopharyngioma team'. OBJECTIVE: To evaluate direct postoperative and long-term results based on the extent of surgical removal and administration of radiotherapy. PATIENTS AND METHODS: Sixty-two new cases of pediatric craniopharyngioma were divided into three groups according to extent of removal: A (complete), B (subtotal), and C (partial). Groups A and B receiving primary postoperative radiotherapy were tagged groups Ar and Br. RESULTS: Group A had significantly less recurrence rate than group B (p < 0.005); however, direct postoperative morbidity and mortality were worse (p < 0.05). Group C fared worse than the other two groups. In groups A and B with recurrence and in groups Ar and Br, radiotherapy provided long-term control. CONCLUSION: The aim at first surgery should be total removal. Subtotal removal is warranted for more resilient tumors, while partial removal should be avoided as it provides poor results. Adjuvant radiotherapy is a useful tool in providing long-term tumor control.

Adolescent↗

PubMed2005

Medical care costs of Paget's disease of bone in a privately insured population.

INTRODUCTION: Medical care costs are difficult to calculate in diseases such as Paget's disease because they have low detection rates and a wide range of clinical manifestations that commonly occur in aging patient populations. MATERIALS AND METHODS: Using 2001-2002 MarketScan Research databases, this study linked medical claims, prescription records, and encounter data on 2.8 million active and retired employees to create a longitudinal panel with 24 months of observation. Patients with Paget's disease were identified by ICD-9 code 731.0. Matched controls (MC) were identified through an exact match procedure using gender, age, and predicted Medicare costs estimated with a risk adjuster. Diagnostic and expenditure records were extracted for the sample and prevalence rates calculated for 20 conditions with well-documented associations to Paget's disease. Comorbidities and health care costs of Paget's disease patients were compared to those of the MCs, and the differences tested using Chi-square and t tests. RESULTS: Our study identified 244 matched pairs. The average age was 72.7 years; 50.8% were female. Significantly higher comorbidities (P < 0.05) were detected in Paget's disease patients relative to MCs for: pathological fractures (4.9% vs. 0.4%), heart murmurs (3.3% vs. 0.4%), low back pain (19.7% vs. 8.6%), spinal stenosis (16.4% vs. 9.8%), and hearing loss (13.5% vs. 5.7%), respectively. Biannual per patient outpatient costs were significantly higher in Paget's disease patients (Paget's disease $9301 vs. MC $6339, P < 0.05), especially for services associated with physician visits and diagnostic tests. Prescription costs for antiresportive agents and analgesics were also higher (Paget's disease $1115 vs. MC $507, P < 0.05). Inpatient costs (Paget's disease $16,144 vs. MC $21,480) were comparable. CONCLUSION: This study is the first to describe the excessive costs of Paget's disease, based on known patterns of disease expression, evaluation, and treatment.

Aged↗

PubMed2004

The Short Arthritis Assessment Scale: a brief assessment questionnaire for rapid evaluation of arthritis severity in research and clinical practice.

OBJECTIVE: To develop a short, 4-item arthritis severity questionnaire that is simple to score, clinically useful and meaningful, and suitable for use in primary care, where osteoarthritis (OA) is the primary prevalent arthritis illness. METHODS: Data and items from the Medical Outcomes Study Short Form 36 (SF-36), the Western Ontario McMaster Osteoarthritis Index (WOMAC(c)), and visual analog scales (VAS) for pain and patient global severity were studied in 16,519 patients with arthritis. The Short Arthritis Assessment Scale (SAS) was developed by performing multivariable analyses that involved individually adding/subtracting items in differing regression models. The candidate items and scales were then studied by Rasch analysis, and tested for effect size, sensitivity to change, and reliability. The resultant scale was validated using data from a recent OA clinical trial. RESULTS: The VAS pain and VAS global severity scales and 2 items from the WOMAC in the VAS format, difficulty going down stairs and difficulty shopping, were found to be the best predictors of change in health status. The 4-item SAS was reliable (Cronbach's alpha = 0.87), demonstrated good test-retest reliability (Lin's concordance coefficient = 0.85), was unidimensional, and was strongly correlated with other important clinical measures, indicating good construct validity. Using data from a recent randomized clinical trial in OA, the SAS performed better than the WOMAC pain scale and the SF-36 physical component score in detecting change, and at least as well as the clinical trial VAS pain scale. CONCLUSION: The SAS is a 4-item arthritis severity questionnaire that can be easily administered in primary care for patients with OA, but is suitable for use across all arthritis illnesses. Scoring is simple, requiring only the addition of four 10-point scales, and interpretation is straightforward. The SAS may have a role in rapid assessment of the arthritis patient in primary care practice.

Adult↗

PubMedDate not supplied

Spectroscopic, spectrophotometric and potentiometric studies on 3-(naphthylazo)-5-phenylpyrazole dye and its metal chelates.

The electronic absorption spectra of 3-(naphthylazo)-5-phenylpyrazole dye (L) are studied in some organic solvents of different polarities. The spectra comprise three absorption bands, which are assigned to the corresponding electronic transitions. The pKa value of (L) in ethanol-water mixtures have been determined pH-metrically at different temperatures. The thermodynamic parameters delta G zero, delta H zero and delta S zero have also been evaluated. The successive stability constants of some d-transition elements have been determined pH-metrically at 25 degrees C and mu = 0.1 in 60% (v/v) ethanol-water mixture. A 1:1 and 1:2 (M: L) complexes are formed and evidenced by conductometric studies. The solid complexes of Cu(II) have been isolated and characterized on the basis of elemental analysis, TGA and IR data. The complexes formed between (L) and Cu(II) were studied spectrophotometrically in solutions.

Azo Compounds↗