Assistive technology access and service delivery in resource-limited environments: introduction to a special issue of Disability and Rehabilitation: Assistive Technology

This special issue addresses access to and service delivery of assistive technology (AT) in resource-limited environments (RLEs). Access to AT is complicated not simply by limited funds to purchase AT, but by larger ecosystem weaknesses in RLEs related to legislation and policy, supply, distribution, human resources, consumer demand and accessible design. We present eight diverse articles that address various aspects of the AT ecosystem. These articles represent a wide range of AT, many different countries and different research methods. Our goal is to highlight a topic that has received scant research investigation and limited investment in international development efforts, and offer an insight into how different countries and programs are promoting access to AT. We encourage researchers, funders and non-profit organizations to invest additional effort and resources in this area.     

A Rare Case of Carcinoma Cuniculatum Involving the Larynx in Association with a Saccular Cyst

Carcinoma cuniculatum (CC), a rare, well-differentiated variant of squamous cell carcinoma, is uncommon in head and neck sites but when it does occur is most common in the oral cavity. Here we report a rare case of CC involving the larynx. A 49-year-old man presented with 10 months of worsening hoarseness and, despite multiple biopsies, no diagnosis of malignancy could be established. Eventual partial excision of the lesion and histologic review of prior specimens confirmed the diagnosis of CC. Focally, a transition to respiratory epithelium indicated the presence of an associated saccular cyst. Total laryngectomy was performed and 6 months later the patient is free of disease. Only two prior cases of CC have been reported in the larynx. Diagnosis of CC is challenging given the low grade histologic features and awareness of this entity for both treating physicians and the pathologist is important to reach a diagnosis of malignancy. This case highlights the challenges in diagnosis of CC, especially in unusual locations and when associated with other lesions such as a saccular cyst. Awareness of this rare tumor type combined with close communication between treating clinicians, radiologists and pathologists should allow earlier diagnosis and treatment.     

Factors influencing mortality in acromegaly

Studies of acromegaly have shown a doubling of mortality compared with the general population. With the development of new modalities of treatment, it has become important to identify prognostic factors relating to mortality. Between 1964 and 2000, 208 acromegalic patients were followed for a mean of 13 yr at Auckland Hospital. Treatment was by surgery or radionuclide pituitary implantation, and all except 27 patients received pituitary radiation. Over the duration of the study, 72 patients died at a mean age of 61 +/- 12.8 yr. Those dying were significantly older at diagnosis, had a higher prevalence of hypertension and diabetes, and were more likely to have hypopituitarism. The observed to expected mortality ratio (O/E ratio) fell from 2.6 (95% confidence interval, 1.9-3.6) in those with last follow-up GH greater than 5 microg/liter to 2.5 (1.6-3.8), 1.6 (0.9-3), and 1.1 (0.5-2.1) for those with GH less than 5, less than 2, and less than 1 microg/liter, respectively (P < 0.001). Serum IGF-I, expressed as an SD score, was significantly associated with mortality, with O/E mortality ratios of 3.5 (95% confidence interval, 2.8-4.2) for those with an SD score greater than 2, 1.6 (0.6-2.6) for those with an SD score less than 2 (normal or low levels), and 1.0 (0.1-3) for those with an SD score less than zero. When assessed by multivariate analysis, last serum GH (P < 0.001), age, duration of symptoms before diagnosis (P < 0.03), and hypertension (P < 0.04) were independent predictors of survival. If IGF-I was substituted for GH, then survival was independently related to last IGF-I SD score (P < 0.02), indicating that GH and IGF-I act equivalently as predictors of mortality. These findings indicate that reduction of GH to less than 1 microg/liter or normalization of serum IGF-I reduces mortality to expected levels.     

Endocrine sequelae after radiotherapy in childhood and adolescence

Radiotherapy may result in endocrine abnormalities, osteoporosis, obesity and neurological sequelae in patients treated for cancer. In the hypothalamo-pituitary area, GH deficiency is the most frequent complication. The frequency, delay of appearance and severity of GH deficiency depend most on the dose delivered during cranial irradiation but variables as age at treatment and fractionation schedule may play an important role as well. Other hypothalamo-pituitary dysfunctions are also dose-dependent. Low dose cranial irradiation may induce precocious or early puberty, while high doses are related to gonadotropin deficiency. Endocrine complications due to extracranial irradiation such as gonadal or thyroid abnormalities are described. In spite of normal GH secretion, linear growth may be impaired by bone lesions secondary to craniospinal or total body irradiation. Results on final height have been optimized by better indicators of GH therapy associated with adequate treatment of early or precocious puberty. The purpose of this review is to explore the late endocrine sequelae of radiotherapy.     

Emphysema in α<Subscript>1</Subscript>-Antitrypsin Deficiency

Severe alpha(1)-antitrypsin (AAT) deficiency is an inherited disorder that leads to the development of emphysema in smokers at a relatively young age; most are disabled in their forties. Emphysema is caused by the protease-antiprotease imbalance when smoking-induced release of neutrophil elastase in the lung is inadequately inhibited by the deficient levels of AAT, the major inhibitor of neutrophil elastase. This protease-antiprotease imbalance leads to proteolytic damage to lung connective tissue (primarily elastic fibers), and the development of panacinar emphysema. AAT replacement therapy, most often applied by weekly intravenous infusions of AAT purified from human plasma, has been used to partially correct the biochemical defect and raise the serum AAT level above a theoretically protective threshold level of 0.8 g/L. A randomized controlled clinical trial was not considered feasible when purified antitrypsin was released for clinical use. However, AAT replacement therapy has not yet been proven to be clinically effective in reducing the progression of disease in AAT-deficient patients. There was a suggestion of a slower progression of emphysema by computed tomography (CT) scan in a small randomized trial. Two nonrandomized studies comparing AAT-deficient patients already receiving replacement therapy with those not receiving it, and a retrospective study evaluating a decline in FEV(1) before and after replacement therapy, suggested a possible benefit for selected patients. Because of the lack of definitive proof of the clinical effectiveness of AAT replacement therapy and its cost, we recommend reserving AAT replacement therapy for deficient patients with impaired FEV(1) (35-65% of predicted value), who have quit smoking and are on optimal medical therapy but continue to show a rapid decline in FEV(1) after a period of observation of at least 18 months. A randomized placebo-controlled trial using CT scan as the primary outcome measure is required. Screening for AAT deficiency is recommended in patients with chronic irreversible airflow obstruction with atypical features such as early onset of disease or disability in their forties or fifties, or positive family history, and in immediate family members of patients with AAT deficiency.     

Identification of glycoprotein Ib as a target for autoantibody in idiopathic (autoimmune) thrombocytopenic purpura

An antibody (DIL) from a patient with idiopathic thrombocytopenic purpura (ITP) was shown to have autospecificity on the basis of reactions with autologous platelets that were identical to those obtained with platelets from normal subjects. DIL antibody also reacted strongly in an immunofluorescence test with platelets from a patient with Glanzmann's thrombasthenia, but failed to react with platelets from a patient with the Bernard-Soulier syndrome who was known to be deficient in glycoprotein Ib (GPIb). Purified GPIb and control platelets, but not Bernard-Soulier platelets, inhibited the lytic activity of DIL. Using the GPIb-specific monoclonal antibody AP1 and one-dimensional rocket electrophoresis into gels containing rabbit antihuman platelet membrane antibody, it was shown that staphylococcal protein A-Sepharose beads coated with DIL antibody selectively remove GPIb from solubilized platelet preparations. By crossed immunoelectrophoresis it was found that DIL recognizes a determinant on GPIb on the membrane side of the cleavage site of the platelet calcium- activated protease (calpain). These studies provide direct evidence for binding of a platelet autoantibody to a determinant on GPIb relatively close to the site of insertion of this protein into the platelet membrane.