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Biomedical subjects

S Nasser

Publications and source records attributed to S Nasser.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effect of endobronchial aspirin challenge on inflammatory cells in bronchial biopsy samples from aspirin-sensitive asthmatic subjects.

BACKGROUND: The aspirin-induced bronchoconstriction in patients with aspirin-sensitive asthma is caused by cysteinyl leukotriene release. The cellular source of the leukotrienes is unknown. The inflammatory cell infiltrate in bronchial biopsy samples from seven aspirin-sensitive asthmatic (ASA) subjects and eight non-ASA subjects before and after local challenge with lysine aspirin was therefore examined. METHODS: Using flexible bronchoscopy, airway mucosal biopsy samples were taken and lysine aspirin solution was placed directly onto a carina of the contralateral lung. Twenty minutes later a second series of biopsy samples was taken from the site of the local endobronchial lysine aspirin challenge. The biopsy samples were double immunostained with a rabbit polyclonal antibody to the enzyme 5-lipoxygenase and monoclonal antibodies to mast cells (AA1), neutrophils (NP57), macrophages (EBM11), T lymphocytes (anti-CD3), and total (BMK13) and activated eosinophils (EG2). RESULTS: A decrease in both absolute mast cell numbers staining with mast cell tryptase (AA1) and the percentage of mast cells co-immunostaining with 5-lipoxygenase was seen in the ASA patients after lysine aspirin challenge compared with the non-ASA control group. There was also an increase in the numbers of activated eosinophils (EG2) in the ASA subjects compared with the non-ASA group. No changes were observed in the total numbers of macrophages (EBM11), neutrophils (NP57), total eosinophils (BMK13), and T lymphocytes (anti-CD3) after challenge with lysine aspirin. CONCLUSIONS: The decrease in numbers of mast cells staining for tryptase and the increase in activated eosinophils after endobronchial challenge with lysine aspirin may represent degranulation of these cell types, and may be an early event associated with aspirin-sensitive reactions in ASA subjects.

Administration, Topical↗
PubMed1994

The incidence of sepsis after total hip replacement arthroplasty.

The incidence of surgically acquired infection during the first 2 years after total hip arthroplasty has decreased more than 10-fold since the introduction of the procedure. Advances in surgical procedures, sterile technique, and antibiotic prophylaxis have contributed to the current incidence of less than 0.5% in most major centers. At the present time, the majority of cases are not related to intra-operative contamination, but to late seeding of the joint from bacterial sources elsewhere in the body. Unfortunately, the overall infection rate (when late sepsis is included) remains at over 1%, and will likely increase as the life expectancy of implants is increased and patients are followed up longer. Given that late sepsis is now the most common type of infection involving total hip replacements, attempts to reduce the infection rate must be directed toward this patient population. Methods must include patient education to prevent sepsis, as well as to identify potentially dangerous infections early so they can be treated expeditiously. The development of a sound basis for antibiotic prophylaxis in cooperation with our medical and dental colleagues in this regard will be welcome. The prompt treatment of infections before they can spread to the prosthetic joint is essential for the continued well-being of the total hip arthroplasty patient.

Antibiotic Prophylaxis↗
PubMed1993

[Incidentally discovered adrenal tumor: myelolipoma].

The wider application of increasingly sensitive ultrasonography and CT scanning has created a new problem for clinical management: the incidental discovery of asymptomatic adrenal lesions. These lesions, also called "incidentalomas" may be due to a large variety of etiologies, and although most of them prove to be benign cortical adenomas, diagnostic confirmation is frequently impossible preoperatively. For this reason, a general approach, based on the relative prevalence of benign and malignant, clinically silent adrenal masses, has been defined. This same approach is usually needed in the case of myelolipoma, a rare form of benign and silent adrenal neoplasms, containing hematopoietic and fatty elements. Actually, computed tomographic aspect of such tumors is very evocative but not pathognomonic, so it doesn't eliminate the possibility of malignant lesions, especially in the presence of heterogeneities. Because of these limitations and awaiting the development of more specific diagnostic procedures, it seems cautious to approach these tumors like incidentalomas in general.

Adrenal Gland Neoplasms↗
PubMed1992

Sleep apnoea: causes, consequences and treatment.

An awakening has taken place over the last 25 years to the science of sleep disorders. Foremost amongst these, both in the medical world and the public eye, has been Sleep Apnoea Syndrome (SAS). The prevalence is thought to be the order of 1-2%. Males are eight times more commonly affected than females, although after the menopause the gap narrows considerably. Sleep apnoea occurs in children, usually in relation to large tonsils and adenoids, but in adult life patients usually present between the age of 40 and 60 and the prevalence increases with age. Numerous apnoeas or hypopnoeas during the night's sleep result in disordered sleep architecture and unrefreshing sleep. This is usually accompanied by night-long snoring which may lead to marital discord and even complaints from neighbours. Symptoms on waking may be a headache and a feeling of not being refreshed by sleep. Sleepiness during the day can interfere with work and social activities and may produce risks to the patient and others if it occurs while operating dangerous machinery or driving. Over a longer time scale SAS results in intellectual and memory deterioration, a higher incidence of ischaemic heart disease, hypertension, polycythemia and pulmonary hypertension. Right heart failure is particularly likely if there is chronic airflow obstruction contributing to a low arterial oxygen level. Asystolic periods and tachyarrhythmias may occur during apnoeic periods. The increased mortality of SAS relates to coronary and cerebrovascular disease and arrhythmias. Sudden death occurs with greater frequency in patients with SAS, mainly at night.

Female↗
PubMed1992

Prevention and treatment of sepsis in total hip replacement surgery.

In spite of improvements in prevention and treatment, sepsis following joint replacement still remains. Deep sepsis can lead to additional operative procedures, prolonged disability, and potential death. A universally effective treatment regimen is unknown. Prevention, therefore, remains the only truly effective means of treatment for sepsis.

Anti-Bacterial Agents↗
PubMed1992

Deep venous thrombosis in total hip arthroplasty.

Deep venous thrombosis (DVT) is the most common complication of total hip arthroplasty. This article discusses the pathogenesis and diagnosis of DVT and recommends prophylaxis and treatment options.

Hip Prosthesis↗
PubMed1990

Effect of diarrhoeal disease control on infant and childhood mortality in Egypt. Report from the National Control of Diarrheal Diseases Project.

The effect of the National Control of Diarrheal Diseases Project, started in 1983, on infant and childhood mortality in Egypt was assessed by means of national civil registration data, nationwide cluster sample surveys of households, and local area studies. Packets of oral rehydration salts are now widely accessible; oral rehydration therapy is used correctly in most episodes of diarrhoea; most mothers continue to feed infants and children during the child's illness; and most physicians prescribe oral rehydration therapy. These changes in the management of acute diarrhoea are associated with a sharp decrease in mortality from diarrhoea, while death from other causes remains nearly constant.

Cause of Death↗
PubMed1990

Fracture of the entire posterior process of the talus: a case report.

A 31-year-old man sustained a displaced fracture of the entire posterior process of the talus. Despite anatomic reduction and internal fixation, limitation of ankle and subtalar joint motion persisted at follow-up, 32 months after the injury. Great toe dorsiflexon was also limited, presumably from flexor hallucis longus tethering behind the ankle joint. The fracture healed without evidence of avascular necrosis of either the talar body or the posterior fragment.

Adult↗
PubMed1990

Cementless total joint arthroplasty prostheses with titanium-alloy articular surfaces. A human retrieval analysis.

Surgical implants of titanium alloy (Ti-6Al-4V) have been found to be susceptible to abrasive wear, resulting in the well-known phenomenon of metallosis. In the presence of the acrylic debris generated by loose joint arthroplasty prostheses, this abrasive wear is greatly increased. However, the bone loss seen in these cases has generally been presumed to be due to the osteolytic effects of particulate acrylic, not the alloy debris, which has generally been assumed to be biocompatible. To examine the in vivo effects of titanium-alloy wear without the added presence of acrylic debris, a comprehensive analysis was made of cementless human joint arthroplasty prostheses with Ti-6Al-4V alloy surfaces articulating on ultra-high molecular weight polyethylene (UHMWPE). Specimens, including the prostheses, synovium, pseudocapsule and additional soft tissues, and periarticular bone, were retrieved from 22 hips and two knees. Specimens were examined by histologic techniques, energy-dispersive X-ray analysis, and electron microscopy. Serial sections of the implants were evaluated for tissue ingrowth. Tissues surrounding all joints implanted more than one year showed some degree of discoloration indicative of metallosis, whereas after two years the synovium was hypertrophic and villiform. Histologic evaluation showed good fixation by bony ingrowth in the vast majority of cases, although location and extent of ingrowth was dependent on numerous factors. Viability of ingrowth bone was established by fluorochrome labeling. However, despite good biologic fixation, cavitary osteolysis of the bone surrounding the implants was frequently identified. These lesions were filled with sheets of aggressive macrophages within a matrix of fibrous tissue and necrotic debris. Under polarized light the macrophages were found to be filled with alloy and polyethylene fragments of a characteristic size. Osteoblast-mediated remodeling of bone was infrequently observed. Instead, the bone was resorbed along a front in contact with the granulomatous tissues filling the cystic lesions. Visible burnishing was observed on every articular surface, with a linear relationship between wear and time implanted. By one year the surfaces were covered with a characteristic "scratch and gouge" pattern, similar on all sizes of femoral heads as well as the total knee prostheses. This study demonstrates that the combination of Ti-6Al-4V alloy and UHMWPE, when used as a bearing surface combination in total joint arthroplasty prostheses, results in excessive wear of both metal and polymer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1990

Treatment of osteoarthrosis secondary to congenital dislocation of the hip. Primary cemented surface replacement compared with conventional total hip replacement.

Seventy-four cemented conventional total hip arthroplasties (in fifty-five patients) and thirty-seven cemented surface replacements (in thirty-two patients) were done between 1971 and 1984 for treatment of osteoarthrosis secondary to congenital dislocation of the hip. The patients in the first group were older and had more severe dysplasia. In all patients, we tried to position the acetabular component at the level of the true acetabulum. In both groups, the operation relieved pain and improved the function of the hip in the short term. There were fewer and less severe early postoperative complications in the surface-replacement group, but the rate of long-term failure (revision or resection) was substantially higher. Survivorship analysis demonstrated that neither type of operation yielded durable results in younger patients; all revisions were in patients who were less than sixty years old. However, in older patients who had cemented conventional total hip arthroplasty, survivorship was excellent, regardless of the amount of dysplasia.

Adult↗
PubMed1989

Preliminary results of an off-the-shelf press-fit stem. The anthropometric total hip femoral component using exact-fit principles.

The use of custom-manufactured femoral prostheses as part of routine total hip arthroplasty (THA) has been suggested. However, there are several disadvantages, including possible inaccuracy of fit, inadequate instrumentation, and high cost. A series of 28 THAs (including 18% for revision of failed, cemented THA) using a press-fit prosthesis of contemporary design were investigated. The average follow-up period was 28 months (range, 12-49 months). Clinical results were overall very good, even in revision cases. Roentgenographic changes included rapid femoral remodeling, which may increase component stability. Given the clinical and roentgenographic results obtained in this complex-problem patient population, it is difficult to justify the use of custom femoral components in routine THA.

Adult↗
PubMed1989

The anthropometric total hip femoral prosthesis. Preliminary clinical and roentgenographic findings of exact-fit cementless application.

Total hip arthroplasty in the young patient remains a considerable challenge. Cemented arthroplasty has an unacceptably high failure rate. Porous ingrowth designs are one alternative, but bone ingrowth is unpredictable, thigh pain is a frequent clinical finding, stress shielding is often observed, revision is more complicated, and microporous components are mechanically weaker. A new anthropometric femoral component has been designed with a goal of long-term stability through osseointegration. The prosthesis is optimized for canal fill in the distal metaphysis and proximal diaphysis. The components are manufactured in 16 sizes, with cutting broaches precisely machined to the same dimensions to provide an exact fit to the femur. The high-strength TiAl6V4 alloy stem is combined with heads of either CoCr alloy or alumina (Al2O3) for reduced polyethylene wear. The 135 degrees neck-shaft angle and modular design allow for restoration of the abductor lever arm. Because the prosthesis is not porous coated, it is also suitable for use with cement. In cemented application, the prosthesis shape provides an optimal cement mantle. Seventy-one total hip arthroplasties have been performed using the Anthropometric Total Hip (ATH) prosthesis: 31 with exact-fit cementless fixation and 40 with cement. Of those using cementless fixation, 21 have been followed for more than one year (mean, 20 months; range, 12-48 months). The early clinical findings are as good as, or superior to, other cementless designs used at the authors' institution. Stress remodeling of the proximal femur occurs early and stabilizes by one year. The observed changes appear to improve the stability of the prosthesis. Clinical and roentgenographic findings suggest the osseointegration of the ATH femoral component.

Adult↗
PubMed1979

Characterization of the myoglobin of the lamprey Petromyzon marinus.

Myoglobin has been identified in the myocardium of the lamprey Petromyzon marinus, one of the most primitive of all vertebrates. This protein was isolated by ammonium sulphate fractionation and purified by successive chromatography on Ultrogel AcA 54, DEAE-Sephadex and CM-23 cellulose. The molecule differs substantially from the monomeric hemoglobins found in the lamprey as evidenced by its elution profile on DEAE-Sephadex and the fingerprint pattern of its enzymically-produced peptides. The functional significance of this protein in Agnatha is discussed.

Amino Acid Sequence↗