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Biomedical subjects

D M Simpson

Publications and source records attributed to D M Simpson.

At least 91 records · Page 5Linked to original sources

Pseudoneurogenic thoracic outlet syndrome.

A 61-year-old man developed progressive weakness, numbness, and exercise-induced vascular symptoms in the left hand. There was left thenar wasting. The presence of a supraclavicular bruit and vascular studies indicated left subclavian artery stenosis, but electrophysiological studies demonstrated no evidence for brachial plexopathy. Subsequent neuroimaging studies revealed multifocal right cerebral infarction. Focal atrophy and weakness from a cerebral lesion can simulate a branchial plexus lesion.

Brachial Plexus↗

Survey of El Paso physicians' breast and cervical cancer screening attitudes and practices.

One hundred and ninety-eight primary care physicians in El Paso, Texas, were surveyed for their practices and attitudes concerning breast and cervical cancer screening. The response rate was 83%. For women 40-49 years old, 77% of respondents stated that they ordered a screening mammogram at least every two years. For women 50-74 years old, 73% said they ordered an annual screening mammogram. For women 75 years and older, 61% stated they ordered an annual screening mammogram. For women 40 years or older, 89% of respondents said they performed annual or more frequent clinical breast examinations. Eighty-four percent of respondents stated they ordered a Pap smear every 1-3 years, both for pre- and post-menopausal women. The most common reasons given for not ordering or doing a breast or cervical screening exam were patient refusal, knowledge that other doctor performs exam, high price, inadequate insurance, patient not under regular care, do not see patient for gynecologic care, and patient being seen for different reason. Seventy percent of respondents do vaginal smears on women who have had a total hysterectomy for a benign condition, and 38% use a cytobrush for endocervical sampling. Respondents were generally more comfortable with their ability to do Pap smears (72% comfortable, 1% uncomfortable) than they were in performing clinical breast examinations (52% comfortable, 4% uncomfortable). Obstetricians and gynecologists were more likely than other physicians to do vaginal smears, use a cytobrush, and feel comfortable with their Pap smear technique.

Adult↗

Outbreaks of syphilis in rural Texas towns, 1991-1992.

Between 1986 and 1990, rates of primary and secondary syphilis increased 134% in rural counties in the South. Reasons for the increases are speculative. During the 14 months ending in October 1992, outbreaks in four eastern Texas counties provided an opportunity to characterize syphilis in rural Texas. We reviewed records for 118 patients and 339 sex partners. Three outbreaks were concentrated in neighborhoods where crack cocaine dealers conducted business and exchange of sex for drugs or money was common; the fourth outbreak involved out-of-town prostitutes who visited undocumented alien workers. Among the 118 syphilis cases, 15 (13%) were primary, 35 (30%) were secondary. Most patients were black (105, 89%); the male-female ratio was 1:1. One woman gave birth to an infant with congenital syphilis. Almost half of the sex partners were infected. HIV pretest counseling was completed for only 55 patients (47%), and only 23 (19%) were tested for the human immunodeficiency virus. These four rural outbreaks of syphilis associated with crack cocaine and the exchange of sex for drugs or money mirror recent urban syphilis outbreaks. Patients in these rural syphilis outbreaks are at risk for HIV infection, but HIV testing has not been emphasized by public health workers.

Adult↗

Neurologic complications of AIDS: new concepts and treatments.

As patients progress from seroconversion to progressive HIV-1 disease, a variety of neurologic disorders may occur. These include diseases of the central and peripheral nervous systems as well as primary muscle disorders. This presentation focuses on clinical, laboratory, and pathologic features of these disorders. Theories of pathogenesis and currently available treatments are reviewed.

AIDS Dementia Complex↗

Real-time digital processing of Doppler ultrasound signals and calculation of flow parameters.

Vascular diseases and their complications are responsible for around 27% of deaths in Brazil. Doppler ultrasound is a non-invasive technique that has been used to study blood flow in intact blood vessels since Satomura first reported the potential of the technique in 1959. Because it is non-invasive it makes sequential studies and those in normals feasible. Whereas in contrast angiography only vessel anatomy is displayed, Doppler ultrasound produces dynamic information on blood-flow. It may be used to estimate flow-rates, to image regions of blood flow (colour Doppler), and to help in locating sites of arterial disease, thus complementing X-ray examinations. This paper describes a system based on a Digital Signal Processor for real-time spectrum analysis of Doppler ultrasound signals, real-time display of sonograms, and calculation and analysis of three parameters of clinical interest derived from the Doppler signal. The system comprises a TMS320C25 development board, which acquires the signal and performs spectrum analysis, and a microcomputer, which reads the spectral estimates, displays them as a sonogram in real-time and calculates a set of spectral parameters proposed in the literature. The system permits a maximum sampling frequency of 40.96 kHz, and in the sonogram, 80 power spectra per second (each with 128 frequency bins) are displayed. In a preliminary study, the stability of the haemodynamic parameters and their dependence on a user-defined threshold value is investigated.

Algorithms↗

HTLV-1 in acquired adult myopathy.

We report a 53-year-old Jamaican man with 20 years of progressing weakness involving proximal limb muscles and neck flexors. Serum CK was 1100 IU/L. EMG demonstrated spontaneous activity, myopathic motor units, and full recruitment patterns in weak muscles. Muscle biopsy revealed marked myofiber degeneration with extensive fibrosis, suggesting a chronic myopathic process. HTLV-1 antibody was present in serum in high titers by ELISA and Western blot. Immunohistochemistry with rabbit polyclonal antisera to HTLV-1 showed rare staining myocytes. PCR demonstrated HTLV-1 DNA in frozen muscle tissue. This myopathy, associated with HTLV-1 infection, has clinical and pathological features similar to a dystrophy. We recommend serological screening for HTLV-1 in cryptogenic adult myopathies.

HTLV-I Infections↗

Vocal cord paralysis: clinical and electrophysiologic features.

Vocal cord paralysis may occur in isolation or as part of a constellation of findings in neurological disease. We investigated the pathophysiology of these disorders with laryngeal electromyography (LEMG). We studied 44 patients with idiopathic vocal cord paralysis, confirmed by laryngoscopy. The major LEMG finding, present in 29 vocal cords, was evidence of active or chronic denervation in the thyroarytenoid (TA), indicating recurrent laryngeal neuropathy. Denervation of the cricothyroid (CT) in 5 patients indicated superior laryngeal neuropathy. TA and CT involvement in 1 patient indicated proximal laryngeal or vagus nerve damage. LEMG was performed in 48 patients with other laryngeal disorders. LEMG proved to be a safe and effective procedure in the diagnosis of laryngeal neuropathy as distinguished from supranuclear and mechanical disorders of the larynx.

Electromyography↗

Myopathies associated with human immunodeficiency virus and zidovudine: can their effects be distinguished?

Myopathy may occur as a complication of human immunodeficiency virus type 1 (HIV) infection or from its treatment, zidovudine (ZDV). We reviewed our experience with HIV-infected subjects referred for neuromuscular evaluation and compared features of myopathy in ZDV-treated (+ZDV) and untreated (-ZDV) patients. Fifty patients had myopathy, 25 diagnosed by pathologic criteria and 25 by clinical and other laboratory support. Twenty patients with myopathy had weight loss sufficient for the diagnosis of HIV wasting syndrome. Thirty-one subjects were +ZDV and 19 were -ZDV. Patients in each group presented with proximal weakness, although myalgia was more common in +ZDV patients. Both groups had elevated serum CK to a similar degree (medians: +ZDV, 485; -ZDV, 471). Muscle biopsies revealed myofiber degeneration, variable inflammatory infiltrates, inclusion bodies, and mitochondrial abnormalities in both groups. We followed response to ZDV withdrawal in 15 patients. Four had increased strength, three noted less myalgia, and eight had no clinical improvement. Twelve of 13 patients improved with prednisone. Although it is difficult to distinguish the myopathies of HIV and ZDV by clinical or pathologic criteria, in the majority of our patients, myopathy is due to HIV rather than ZDV.

AIDS-Related Complex↗

Neuromuscular complications of human immunodeficiency virus infection.

As the lifespan of patients with HIV infection is prolonged with more effective antiviral therapies, the prevalence of neuromuscular disorders is likely to increase. The understanding of the pathogenesis and optimal therapy of these illnesses has advanced during the past 5 years. However, there are still significant gaps in our knowledge. It is important that neurologists remain at the forefront of investigation and treatment of these complex disorders.

HIV Infections↗

Peripheral neuropathies associated with human immunodeficiency virus infection.

In the 1990s, HIV has replaced syphilis as the "great masquerader." Virtually every level of the neuraxis may be affected in a patient with HIV infection. The superimposition of multiple levels of neuropathology further complicate the bedside neurologic diagnosis of an AIDS patient. This article has reviewed the variety of forms of peripheral neuropathy that may be associated with HIV infection and its treatment. Distal symmetrical polyneuropathy may be produced in patients with HIV infection by neurotoxic drugs (e.g., vincristine, INH, ddC, or ddI) or by vitamin B12 deficiency or may develop in the later stages of HIV infection without identifiable cause. GBS and CIDP occur with increased frequency in early HIV infection owing to presumed autoimmunity, and these IDPs respond to plasmapheresis or prednisone, similar to HIV-seronegative patients. A limited distribution of mononeuropathy simplex or multiplex occurs in patients with CD4 counts greater than 200; the neuropathy will usually spontaneously improve in these patients. Widespread mononeuropathy multiplex may occur in patients with AIDS and CD4 counts less than 50 and is then usually caused by CMV infections; those neuropathies are usually progressive unless antiviral treatment is given. Progressive polyradiculopathy usually occurs in patients with AIDS and low CD4 counts. If the cerebrospinal fluid has a polymorphonuclear pleocytosis, CMV infection is almost always present, and progression is expected unless ganciclovir therapy is promptly started. Finally, mild autonomic neuropathy is commonly present in HIV-infected patients. Protocols for the evaluation and therapy of cranial and peripheral neuropathies are presented (Figs. 6 and 7). It is unfortunate but likely that increasing numbers of "neuro-AIDS" patients will be encountered, not only in urban medical centers but also in general community practice. The pace at which research in the field of HIV research has proceeded is unprecedented. It is, therefore, important that neurologists stay at the forefront of investigation and clinical care of these complex disorders.

Autonomic Nervous System Diseases↗

Involving the patient can free resources.

Involving the patient in the scheduling of theatres by a Diary Booking System improves patient choice and thus the quality of service offered. To assess the feasibility and cost effectiveness of such a system, a trial was conducted within ENT surgery. One consultant's theatre schedules were analysed before and after the introduction of a diary booking system. A second consultant's schedules, not using a diary booking system, were analysed to confirm the absence of seasonal variation or other factors. The trial consisted of three months' schedules before introduction and three months after introduction. The feasibility of the system was confirmed. The trial reduced cancellations by 32% and failures to attend by 68%. The introduction of the Diary Booking System increased the number of operations conducted by nearly one per session.

Appointments and Schedules↗

Collagen cross-linking in bovine gingiva.

Tissue samples from 5 different sites of 6 bovine mandibles were used to quantify collagen cross-links as moles cross-link per mole of collagen. Gingiva contained primarily 3 reducible cross-links, deH-DHLNL, deH-HHMD, and deH-HLNL, and relatively small amounts of non-reducible cross-links. The cross-link density varied from site to site within the same mandible. DeH-DHLNL showed the most significant increase from anterior to posterior; the content in the retromolar region was 3-fold greater than in the anterior lingual site. Histologically, the posterior samples, especially the retromolar gingiva, contained less mature (thinner) collagen bundles. These findings suggest that the maturity of bovine mandibular gingival collagen varies at different sites.

Animals↗

Human immunodeficiency virus infection in Northern Ireland 1980-1989.

To 31st December 1989, 71 persons are known to have attended medical practitioners in Northern Ireland with a diagnosis of Human Immunodeficiency Virus (HIV) infection. Twenty-one of these persons have had the diagnosis of Acquired Immune Deficiency Syndrome (AIDS) and 11 have died. The distribution of reports in the "at risk" categories of homosexual/bisexual males, injecting drug users, heterosexual males and females was significantly different (p less than 0.001) from those reported in the United Kingdom as a whole. Of tests for HIV infection carried out in patients attending the genitourinary medicine department of the Royal Victoria Hospital between 1987-1989, 0.16% have been positive. The prognostic value of the T4 lymphocyte count at presentation for the subsequent development of AIDS was significant (p = 0.0011). The commonest AIDS indicator disease diagnosed was Pneumocystis carinii pneumonia which was seen in seven of the 21 patients (33%).

Acquired Immunodeficiency Syndrome↗