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Biomedical subjects

A Nasr

Publications and source records attributed to A Nasr.

At least 37 records · Page 2Linked to original sources
PubMed1989

The use of carbon dioxide laser in lichen myxedematosus.

Lichen myxedematosus is characterized by deposits of mucin in the dermis. Treatment can be systemic or local, depending on the clinical findings. We present a patient with pedunculated lesions on his nose, and a generalized thickening of his facial skin. The patient requested treatment of his nasal lesions. We elected to remove his nodules surgically using the carbon dioxide (CO2) laser. The technique is described and treatment options are reviewed.

Humans↗
PubMed1988

Retinoblastoma: the Saudi Arabian experience.

During the period March 1983-May 1987, 74 cases of retinoblastoma were evaluated at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia. 60% of the cases were unilateral with a female preponderance of 59.4% noted for this series. Additionally, the mean age at diagnosis was 22 months, and delay of retinoblastoma diagnosis since the first symptoms were observed ranged from two days to 36 months. Fifty-seven eyes were enucleated, and in 21 of these patients, this was the sole form of therapy. The remainder of patients were treated with radiotherapy alone or combined with chemotherapy, cryotherapy/photocoagulation. Overall, two-year survival statistics of this group of Saudi patients is 80% which compares favorably to other reports in the West. Emphasis is placed on management of the retinoblastoma patients by a multi-disciplinary group, and public educational efforts are imperative.

Child↗
PubMed1985

Alloaffinity filtration: a general approach to the purification of dynein and dynein-like molecules.

Alloaffinity filtration simply and specifically separates certain axonemal dyneins and dynein arm components from crude mixtures on the basis of their ability to bind and decorate Tetrahymena axonemal microtubules on a filter in the absence of ATP and to detach and pass into the eluate when 0.5 mM ATP is added. The procedure, which may be performed repetitively, is successful in purifying a Tetrahymena dynein that has characteristics of 30 S dynein prepared by conventional methods, while other dyneins originally present in the mixture, e.g., 14 S Tetrahymena dynein, are not found in the ATP eluate. A relatively homogeneous population of dynein oligomers is obtained. Alloaffinity-purified 30 S Tetrahymena dynein consists of heavy-, intermediate-, and light-chain polypeptides that cosediment in a sucrose gradient in fixed molar ratios and that have structural features of in situ Tetrahymena arms. Dyneins from other species will bind to Tetrahymena microtubules and can be purified by this method. Alloaffinity-purified Chlamydomonas dynein is a set of polypeptides including the four heavy chains that characterize the outer arm.

Adenosine Triphosphatases↗
PubMed1984

Hereditary retinoblastoma and 13q--mosaicism.

Mosaicism for a 13q interstitial deletion was found in a minor fraction of peripheral blood lymphocytes in a 10-month-old girl affected with bilateral retinoblastoma. The tumor was inherited from the unilaterally affected father.

Adult↗
PubMed1981

The mechanochemical cycle of the dynein arm.

A dynein arm attachment cycle produces sliding between adjacent doublet microtubules (N and N + 1) of cilia. In intact axonemes, in the absence of ATP, almost all arms appear attached at both ends (rigor). When ATP is added, most arms detach from doublet N + 1. In ATP and vanadate, the arms do not return to rigor, suggesting that ATP hydrolysis is required for re-extension and reattachment of the dynein arm, but not for detachment. Using solutions containing dynein to decorate dynein-less axonemal doublets, we confirm this interpretation. In the absence of ATP, both sides of each doublet decorate with arms. Addition of ATP, ATP and vanadate or AMP-PNP causes immediate arm detachment, but only in the first instance, where extensive ATP hydrolysis can occur, does decoration eventually reappear. Dynein decorates heterologous axonemal doublets and brain microtubules, as well as homologous doublets, suggesting that this mechanochemical cycle may have general applicability in microtubule-based cell motility.

Adenosine Triphosphatases↗
PubMedDate not supplied

Impact of emergency admissions on elective surgical workload.

BACKGROUND: Day case surgery is the most cost-effective approach for all minor, most intermediate and some major surgery. AIMS: To examine the effect of the current 'escalation' policy of opening the surgical day ward to A&E admissions at the expense of planned surgery. PATIENTS AND METHODS: A retrospective study was carried out on all elective general surgical operations planned for January through March 2003. The number of cases cancelled and the reasons for cancellation were documented. RESULTS: The total number of patients booked for surgery was 836, 66.6% of which were day cases (557 patients). Overall 338 patients accounting for 40.4% of all planned cases were cancelled. Day case cancellations accounted for 68.9% of all cancellations (233 patients). Bed unavailability was the main reason due to the overflow of A&E admissions, accounting for 92% of cancelled patients and 73.8% of day ward cancellations. CONCLUSIONS: The cancellation of surgery creates untold hardship for patients who plan their working and family lives around the proposed operation date. Most are cancelled at less than 24 hours notice. The cost implications to the community are immense but have not been calculated. The separation of emergency and planned surgery is essential through adequate observation ward access.

Ambulatory Surgical Procedures↗
PubMedDate not supplied

Plexiform soft tissue tumor composed predominantly of perineurial fibroblasts (perineurioma).

A 15-year-old girl presented with a small, indolent mass near the knee joint. Light microscopy revealed a peculiar myxoid plexiform tumor composed of cytologically bland cells. Interpretation of the initial biopsy material was controversial. Subsequent immunohistochemical studies revealed tumor cells to be strongly reactive for epithelial membrane antigen (EMA) and negative for S-100 protein. Ultrastructural studies revealed tumor cells with long, thin, bipolar cell processes and discontinuous basal laminae. They had no epithelial or histiocytoid features. Admixed among the tumor cells were Schwann cells, but they represented a rare and scattered component of the overall cell population. These features are most consistent with a so-called perineurioma and contrast with those of plexiform neurofibroma and traumatic neuroma (two lesions strongly positive for S-100 protein and showing a distinctive EMA immunoreactivity pattern with focal peripheral staining of neural bundles).

Adolescent↗