Biomedical subjects

L Cannon

Publications and source records attributed to L Cannon.

33 records · Page 2Linked to original sources

PubMed1989

Neurological and neuropsychological manifestations of HIV-1 infection: association with AIDS-related complex but not asymptomatic HIV-1 infection.

To determine whether neurological and neuropsychological abnormalities are associated with clinical manifestations of human immunodeficiency virus type 1 (HIV-1) infection in men who do not have acquired immunodeficiency syndrome (AIDS), we performed a historical prospective and cross-sectional study. One hundred HIV-1 seropositive homosexual or bisexual men, of whom 26 had AIDS-related complex, 31 had generalized lymphadenopathy, and 43 had no signs or symptoms of HIV-1 infection, and 157 HIV-1 seronegative men were enrolled from a cohort of 6,701 men who were originally recruited between 1978 and 1980 for studies of hepatitis B virus infection. Evaluation included medical history, physical examination, and neuropsychological tests. Of 26 HIV-1 seropositive subjects with AIDS-related complex, 11 (42%) reported neurological, cognitive, or affective symptoms compared with 30 (19%) of 157 HIV-1 seronegative subjects (relative risk = 2.2, p = 0.02). On neuropsychological testing, subjects with AIDS-related complex performed at a significantly lower level than the HIV-1 seronegative group (p = 0.001). A significantly higher percentage of subjects with AIDS-related complex (8[31%]of 26) than HIV-1 seronegative subjects (19 [12%] of 157) had abnormal results on two or more neuropsychological tests (rate ratio = 2.5, p = 0.03). Symptoms and impairment on neuropsychological tests were correlated only within the group who had AIDS-related complex. Subjects with generalized lymphadenopathy and subjects who had no signs or symptoms of HIV-1 infection were not different from HIV-1 seronegative subjects with respect to symptoms or performance on neuropsychological tests.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS Dementia Complex↗

PubMed1989

Clinical trials of WR-2721 and cis-platinum.

WR-2721 is an aminothiol compound; in the animal model it protects against the nephrotoxicity, neurotoxicity, and hematologic toxicity of cis-platinum. We initiated Phase I trials of WR-2721 and cis-platinum to determine toxicity when WR-2721 was given prior to escalating doses of cis-platinum. With mannitol diuresis and WR-2721, transient nephrotoxicity occurred in 9 of 30 (27%) patients treated with cis-platinum 150 mg/m2 and 7% of patients given with cis-platinum 120 mg/m2. Bone marrow suppression was mild and infrequent. Mild to moderate peripheral neuropathies occurred in 26% of patients courses following a mean cumulative cis-platinum dose of 725 mg/m2. Objective partial responses were observed in 53 of 118 (45%) patients with measurable disease. Antitumor responses were observed in 25 of 53 patients with metastatic melanoma, 12 of 22 patients with locally recurrent or metastatic head and neck cancer, and 7 of 13 patients with metastatic breast cancer refractory to conventional chemotherapy. Controlled studies of WR-2721 and cis-platinum will be performed in the Eastern Cooperative Oncology Group in these disease sites to better define the activity of this regimen and its toxicity.

Adult↗

PubMed1988

Continuous emergency department monitoring of arterial saturation in adult patients with respiratory distress.

Continuous measurement of arterial oxygen saturation (SaO2) using pulse oximetry has become a common monitoring and management technique in critically ill hospitalized patients. To determine the impact of SaO2 monitoring on emergency patient management, we conducted a prospective uncontrolled clinical trial on 40 adult patients presenting to the emergency department with acute respiratory illness, such as emphysema, asthma, or pulmonary edema. Recorded data included hemograms, arterial blood gases, subsequent therapy, and response to treatment. Additionally, the "early warning" capability of SaO2 monitoring was analyzed by recording the severity and outcome of hypoxemic events during treatment. Mean duration of usage for the 40 oximeters in the ED was 1.8 hours; all probes functioned reliably over a wide range of systolic pressures (80 to 206 mm Hg), heart rates (40 to 180 beats per minute), and hematocrits (20% to 58%). There was good correlation between simultaneous pulse oximeter values and both directly measured SaO2 (r = 0.95) and saturations derived from measured arterial PaO2 (r = 0.94). The device detected several otherwise unrecognized drops in arterial saturation that were confirmed by laboratory analysis. Other clinical situations in which the pulse oximeter was found useful in the ED are reviewed. We conclude that continuous measurement of SaO2 can improve the monitoring of ED patients, increase the precision of therapy, detect hypoxemia during intubation, suctioning, and other treatments, and detect clinically unsuspected changes in arterial oxygenation.

Adult↗

PubMed1988

Mapping of Alport syndrome to the long arm of the X chromosome.

Five X-chromosome DNA markers were typed on 261 members of three large kindreds with Alport syndrome (hereditary glomerulonephritis). Lod scores greater than 3.0 for linkage between the disease locus and two of the markers confirmed X-linked inheritance of the disease. A decreasing gradient in the estimated recombination fractions observed when the markers were ordered on the basis of their map locations suggested that the disease locus is on the long arm distal to all the markers typed in this study. Using three-locus analysis we rejected all but three map orders for the six loci (the disease locus and five markers). In all three the Alport syndrome locus was on the long arm of the X chromosome distal to all the markers. Two types of Alport syndrome were represented in the three kindreds. Affected males in one kindred developed deafness in addition to nephritis; deafness did not occur in members of the other two kindreds. Although larger recombination-fraction estimates were obtained for all five markers in the kindreds without deafness, the difference was significant for only one marker. Evidence of heterogeneity was not found in tests using two markers. Markers distal to the disease locus are needed to determine whether two loci are responsible for the two types of Alport syndrome.

Chromosome Mapping↗

PubMed1987

Gene for von Recklinghausen neurofibromatosis is in the pericentromeric region of chromosome 17.

Linkage analysis of 15 Utah kindreds demonstrated that a gene responsible for von Recklinghausen neurofibromatosis (NF) is located near the centromere on chromosome 17. The families also gave no evidence for heterogeneity, indicating that a significant proportion of NF cases are due to mutations at a single locus. Further genetic analysis can now refine this localization and may lead to the eventual identification and cloning of the defective gene responsible for this disorder.

Centromere↗

PubMed1987

Further linkage data on Norrie disease.

We obtained a LOD score of +1.61 using DNA marker L1.28 in 5 generations of a family with Norrie disease, raising the total LOD score to +5.42. There have been no recombinations between the 2 loci in any family to date, making the marker useful for genetic counseling.

Blindness↗

PubMed1987

Repetitive doses of activated charcoal in the treatment of poisoning.

Activated charcoal has found a renewed role in the management of overdosed patients. Routinely administered to reduce the gastrointestinal (GI) absorption of many drugs, growing evidence indicates that repeated doses of charcoal also may enhance drug elimination. Some drugs are excreted into the bile or gastric fluids (phencyclidine, digoxin) and are reabsorbed. Other drugs (theophylline, phenobarbital) can diffuse from the plasma into the lumen of the GI tract. Activated charcoal is administered at regular intervals to sequester these toxins in the GI tract, eventually causing their excretion in feces. This article reviews the evidence for the safety and efficacy of repetitive charcoal therapy. While supportive management remains the mainstay of therapy in poisoned patients, activated charcoal is inexpensive, effective, simple to administer, and may obviate the need for more invasive methods of toxin removal.

Acute Disease↗

PubMed1987

Teaching research in the emergency medicine residency curriculum.

Research in emergency medicine is a necessary component for the growth and development of the academic discipline. Although the need exists for competent physician investigators, most graduates of emergency medicine residencies have had little structured education in research design or methodology. This is particularly true in community hospital programs with little funding allocated to research, limited facilities, and few staff members actively involved in research. Our purpose is to describe a research curriculum designed to operate within a community-based residency program. This curriculum identifies a detailed set of educational objectives in research techniques with the expectation that on completion of the residency program, the resident will be able to critically evaluate medical literature and independently design a research project. We have developed a specific plan for meeting these objectives with coordinated seminars, readings, journal clubs, research projects or exhibits, and professional conferences. We suggest some practical methods of motivating residents and attending staff to pursue clinical investigation.

Curriculum↗

PubMed1987

Odorization of inert gas for occupational safety: psychophysical considerations.

Odorization of inert gas can serve to warn workers in an enclosed space about gas leaking into the space. This psychophysical investigation, performed under conditions of directed attention, examined two candidates for possible odorization of argon:pyridine and cis-3-hexen-1-ol. Detection thresholds for pyridine and cis-3-hexen-1-ol in argon were 106 ppb and 19 ppb, respectively. Practice over four days yielded modest improvement in the detection of both odorants. For cis-3-hexen-1-ol, smokers had marginally lower thresholds than nonsmokers and older participants had slightly higher thresholds than younger participants. Gender, smoking status and age had no reliable influence on threshold for pyridine. This outcome indicated desirable perceptual stability for pyridine. Additional experiments dealt with the perceived intensity of pyridine and cis-3-hexen-1-ol over time in the realistic setting of an environmental chamber. Visitors to the chamber and occupants in the chamber assessed perceived magnitude at 5-min intervals for up to 60 min during injections of odorized argon into the chamber. Participants could gauge and track the concentration of pyridine much better than that of cis-3-hexen-1-ol. This held true for occupants almost to the same degree as visitors, though occupants inevitably exhibited some olfactory adaptation. Hence, the suprathreshold measurements also gave strong relative endorsement to pyridine. Calculations based on the experimental results indicated that odorization of the inert gas stream with 3 to 10 ppm (v/v) pyridine should suffice to warn occupants or visitors of an argon buildup of any severity. Field studies should permit a definitive judgment of the best concentration to use in practice.

Adult↗

PubMed1987

A genomic search for linkage of neurofibromatosis to RFLPs.

Our initial attempt to map NF was directed towards chromosomes 4 and 19, both of which had provided positive evidence for linkage in previous reports. This analysis showed no evidence in support of either hypothesis. Our second attempt at mapping NF was a general search of the genome, analysing a set of markers selected according to their degree of polymorphism, chromosomal location, ease of use, and availability. Data for linkage analysis were obtained from 17 multiplex families which are segregating a gene for NF. Linkage analyses were performed using PAP. Of note is the lod score of +1.17 at a recombination fraction of 0.1 between NF and the centromere of chromosome 17.

Chromosome Mapping↗

PubMed1986

Continuous monitoring of mixed venous oxygen saturation in septic shock.

Fiberoptic pulmonary artery catheters provide a practical method for continuously measuring the amount of oxygen in mixed venous blood. To characterize the usefulness of mixed venous oxygen saturation in managing patients with sepsis, we performed serial hemodynamic measurements on 20 patients with documented septic shock. There was a highly significant positive correlation between increases or decreases of 5% or more in mixed venous oxygen saturation and corresponding changes in oxygen delivery (r = 0.95) and oxygen consumption (r = 0.96). Mixed venous oxygen saturation less than 65% was clinically unacceptable in patients with sepsis and was associated with a poor prognosis. In this study, measurement of mixed venous oxygen saturation was a valuable predictor of survival in patients with septic shock and provided a means of continuously monitoring the status of tissue oxygenation.

Aged↗

PubMed1986

Diphenhydramine-induced toxic psychosis.

A 24-year-old man presented to the emergency department with acute anticholinergic symptoms, hallucinations, and bizarre behavior following a large ingestion of diphenhydramine (Benadryl). Because of the large number of nonprescription preparations containing this antihistamine, similar ingestions are becoming increasingly frequent. Minor anticholinergic side effects associated with diphenhydramine are general medical knowledge. The effects of overdosage are less well known. The clinical presentation of toxic psychosis, its differential diagnosis, and its subsequent treatment are discussed.

Adult↗

PubMed1986

Hypokalemic periodic paralysis.

Generalized motor weakness is a common complaint in the emergency department and has a wide differential diagnosis that includes both organic and infectious etiologies. We report the case of a previously healthy young man with symptoms of muscular paralysis and associated hypokalemia. The clinical presentation of hypokalemic periodic paralysis, its differential diagnosis, and pertinent physical findings are discussed.

Acetazolamide↗

PubMed1986

A geriatrics curriculum for emergency medicine training programs.

The growing number of elderly in the United States will continue to increase the demand for emergency services. Although the emergency medicine core curriculum, as defined by the American College of Emergency Physicians, requires mandatory training in pediatrics, there is no mention of geriatric care. A special body of knowledge regarding normal aging as well as the special presentation of disease in the elderly is required to provide optimum care for the aged patient. We present an integrated geriatric curriculum designed to operate within a three-year emergency medicine residency program. This curriculum identifies specific educational objectives for training in geriatric emergencies that can be summarized as follows: identify those impairments and functional disorders that often complicate diagnosis and therapy; acquire an understanding of how physiologic changes in aging affect normal laboratory and radiologic values; develop knowledge of drug side effects and interactions in this population; understand and treat the group of disease peculiar to the elderly; recognize diseases and injuries that present a different clinical picture in old age; and differentiate and treat common psychosocial emergencies in the elderly. These educational objectives are further defined using a specific interlinked framework of didactic presentations, journal clubs, case conferences, therapeutic audits, formal rotations, and consultants. This format will provide valuable educational experiences for the emergency medicine resident and may strengthen positive attitudes toward geriatric medicine.

Aged↗

PubMedDate not supplied

Persistent hiccups as an unusual manifestation of hyponatremia.

In two patients, persistent hiccups were an unusual presenting manifestation of hyponatremia. Persistent hiccups occur in a variety of serious diseases, including metabolic and electrolyte disorders. They may cause the victim significant distress and may be refractory to most treatments. Hiccups lasting more than 24 hours require investigation for an underlying organic etiology, with hyponatremia included in the differential diagnosis.

Aged↗