Biomedical subjects
D E Kim
Publications and source records attributed to D E Kim.
The limited value of routine laboratory assessments in severely impaired nursing home residents.
OBJECTIVE: To determine the usefulness of a routine, comprehensive battery of laboratory tests in a severely impaired elderly nursing home population. DESIGN: Prospective observational survey. SETTING: Skilled nursing facility wards of a geriatric and extended care veterans hospital. PATIENTS: Consecutive sample of 108 veterans with severe cognitive and functional impairments, who had been hospitalized at least 6 months. MAIN OUTCOME MEASURES: Proportions of tests categorized as screening, monitoring, follow-up, or diagnostic; frequency of abnormal test results, interventions warranted and performed on the basis of these abnormalities, and beneficial or adverse effects. RESULTS: Of 6771 individual nondiagnostic tests performed, 17.2% yielded abnormal results; of these, 33.3% were new. However, only 0.2% of tests resulted in patient benefit. Of 989 panels performed, 31.0% contained at least one abnormality, but only 1.0% of panels (10 patients) yielded any benefit. Overall usefulness was related to the purpose of the testing, with 31.5% of screening tests yielding abnormalities, compared with 45.5%, 78.2%, and 68.7% of monitoring, follow-up, and diagnostic panels, respectively (P < .05 for each compared with screening panels). None of the screening panels detected an abnormality that led to patient benefit, compared with 1.0%, 1.4%, and 3.0% of monitoring, follow-up, and diagnostic panels. CONCLUSIONS: Routine comprehensive laboratory panels may not be warranted in the most severely impaired elderly patients in long-term care settings. Discontinuing true screening tests and limiting testing strictly to monitoring, follow-up, or diagnostic purposes could minimize the costs of laboratory assessment without losing its potential benefits.
What is the best diagnostic index of conduction block and temporal dispersion?
In order to find the best diagnostic index of conduction block and abnormal temporal dispersion, the amplitude, duration, and area of the compound muscle action potentials (CMAP) were studied in 40 normal controls and 28 patients with acquired demyelinating neuropathies. In the normal subjects, there was a substantial difference among the various nerves in the degree of CMAP amplitude reduction and CMAP duration prolongation with proximal stimulation, and thus different criteria should be used for conduction block or abnormal temporal dispersion for a given nerve. In 28 patients with demyelinating neuropathy, 58 of 207 (28%) tested nerve segments showed nerve conduction velocity (NCV) evidence of demyelination. To identify "demyelination" in these segments, conduction block was best detected by the total area method in 71% of cases, and abnormal temporal dispersion was best by the negative-peak duration method. This study showed that the best diagnostic index for conduction block is the total area method and for abnormal temporal dispersion, the negative-peak duration method.
Pyridostigmine toxicity. Electrophysiological study.
A 54-year-old neurotic patient developed pyridostigmine-induced proximal weakness with daily 3600 mg of pyridostigmine. Detailed analysis of the RNS test showed three different types of responses which were reproduced in the in vitro nerve-muscle preparation, confirming that three different responses represent the different degree of pyridostigmine toxicity. One of responses was a pattern, thought to be typical of anticholinesterase toxicity: repetitive discharge and the maximal decrement in the second response followed by an increment (dip phenomenon). With reduction of pyridostigmine, clinical and electrophysiological improvement followed.
Diagnostic sensitivity of the laboratory tests in myasthenia gravis.
The diagnostic sensitivity of three laboratory tests [serum antiacetylcholine receptor antibody (AChR-ab) assay, the repetitive nerve stimulation (RNS) test, and, the single fiber EMG (SFEMG)] for myasthenia gravis (MG) was compared in 120 patients. In all cases, at least one of the tests was abnormal. SFEMG was the most sensitive test, being abnormal in 92% of cases, followed by the RNS test (77%) and the AChR-ab assay (73%). SFEMG was abnormal in all cases with negative AChR-ab and RNS tests, in 97% of cases with negative AChR-ab assay, in 89% of cases with negative RNS test, and in 89% of cases with mild MG. We conclude that one of these three tests is abnormal in all cases of MG, and that the SFEMG is most sensitive in the diagnosis of MG.
Immunoglobulin-degrading enzymes in localized juvenile periodontitis.
Previous reports have indicated the association of periodontal diseases with elevated levels of serum immunoglobulin G (IgG) antibodies to periodontally relevant bacteria. Recent results from this laboratory suggest that enzymes proteolytic for immunoglobulins are important virulence factors of several periodontal bacteria. Specifically, enzymes from Porphyromonas (Bacteroides) gingivalis culture supernatant fluid (SF) cleaved human IgG (4 subclasses), IgA1 and IgA2, IgM, IgD and IgE. Proteolytic enzymes from Actinobacillus actinomycetemcomitans culture SF cleaved IgG, IgA and IgM. An enriched Ig proteolytic preparation from Capnocytophaga ochracea culture SF was shown to extensively cleave all 4 subclasses of human IgG. Extensive degradation of IgG and IgA in crevicular fluid samples on SDS-PAGE from periodontal disease sites of localized juvenile periodontitis (LJP) patients in comparison to little degradation in healthy sites indicated the potential role the proteolytic enzymes from periodontopathogenic bacteria may play in situ. Treatment of IgG with P. gingivalis, A. actinomycetemcomitans and C. ochracea SF resulted in similar patterns of degradation. LJP patients had significantly higher levels of IgG and IgA proteolytic activity in whole saliva than age-, sex-, and race-matched periodontal disease-free controls. However, not all of the proteolytic activity could be ascribed to bacterial proteases since neutrophils are also present in large numbers at diseased sites. Using similar techniques, lysates of neutrophils from healthy controls cleaved IgG, IgA and IgM. The observation of enhanced Ig cleavage activity in crevicular fluid and saliva in LJP patients suggest a role for Ig proteolytic enzymes in LJP.
Electrophysiological improvement following decompression surgery in tarsal tunnel syndrome.
Plantar nerve conduction studies 14 months to 3.5 years after decompression surgery in 3 cases of tarsal tunnel syndrome showed an improvement in motor conduction as well as in sensory nerve conduction. This electrophysiological improvement was associated with clinical improvement. However, minor abnormalities still existed in sensory nerve conduction in all 3 cases.
[Mercury contents in hair of dental personnel and evaluation of various agents suppressing mercury vaporization].
The purpose of the present study was to determine the mercury contents in the hair of 44 dentists and 55 hygienists as dental personnel compared with 37 male and 35 female as controls, total 171 persons in Daegu City, to compare disposable capsule with reusable capsule in their ability to suppress mercury vapour leakage during trituration and opening the capsule, and to test 4 agents (water, detergents, developer, fixer) used to suppress mercury vaporization. The results were as follows: 1. The hair mercury contents of the dental personnel (6.69 +/- 4.01 ppm) were significantly higher than those of the controls (3.03 +/- 1.62 ppm) (p less than 0.01). 2. The hair mercury contents of the hygienists (7.01 +/- 4.48 ppm) were slightly higher than those of the dentists (6.22 +/- 3.40 ppm) but not significant difference (p greater than 0.05). But hair mercury contents in the dentists and hygienists of the same period of year of exposure were 5.22 +/- 1.87 ppm, 7.01 +/- 4.48 ppm, respectively, so hair mercury contents of the hygienists were significantly higher than those of the dentists (p less than 0.05). 3. In the controls, hair mercury contents of the male (3.48 +/- 1.56 ppm) were significantly higher than those of the female (2.56 +/- 1.60 ppm) (p less than 0.05). 4. There was no correlationship between the hair mercury contents of hygienists and the period of year of exposure (r = 0.0062, p greater than 0.1) but significant correlationship in dentists (r = 0.5410, p less than 0.002). 5. Disposable capsule exhibited mercury vapour leakage during trituration and opening the capsule, 0.80 microgram, 1.97 microgram, respectively so opening the capsule was increased by 2.5 times. Reusable capsule exhibited mercury vapour leakage during trituration and opening the capsule, 0.94 microgram, 7.26 micrograms, respectively so opening the capsule was increased by 7.8 times. 6. Compared with reusable capsule, disposable capsule suppressed mercury vapour leakage during trituration and opening the capsule 1.2 times, 3.7 times, respectively. 7. Of various agents used to suppress mercury vaporization, 0.56 microgram of mercury in fixer, 0.81 microgram of mercury in developer, 0.94 microgram of mercury in detergent, 1.38 microgram of mercury in mater were released and mercury vaporization was suppressed in fixer compared with air by 12.7 times, with water by 2.5 times.