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Biomedical subjects

S J Oh

Publications and source records attributed to S J Oh.

At least 127 records · Page 7Linked to original sources
PubMed1996

Isaacs' syndrome associated with chronic inflammatory demyelinating polyneuropathy.

We report the first case of Isaacs' syndrome in which an inflammatory demyelinating neuropathy was documented histologically. For 9 months, the patient developed slowly progressive weakness, muscle spasms and stiffness, fasciculations, and myokymia in the arms, which were unmodified by sleep. Nerve conduction studies showed multifocal motor conduction block, abnormal dispersion phenomenon, and abnormal sensory and mixed nerve conduction. Needle electromyogram showed continuous motor unit potentials at rest with bursts of rapid-firing discharges which were unaffected by spinal anesthesia but diminished by peripheral nerve block and completely abolished by local curarization. Sural nerve biopsy demonstrated an inflammatory demyelinating neuropathy. Muscle cramping, twitching, and stiffness responded to phenytoin. The patient's weakness gradually responded to prednisone and azathioprine. Over a 17-year period, the patient had three relapses which were well controlled with prednisone and azathioprine. At this time, the patient is symptom-free without any medication.

Demyelinating Diseases↗
PubMed1995

Modified trichrome staining technique of the nerve to determine proximal nerve viability.

Normal myelinated fibers are stained "red" by modified trichrome staining of the frozen section of the nerve. We have used this technique for rapid assessment of the anatomical integrity of the proximal nerve stump by identifying well-preserved myelinated fibers. This technique can also identify degenerating and degenerated myelinated fibers, fibrosis, and inflammatory cells. We report three cases in which the practical usefulness of this technique is demonstrated.

Cell Survival↗
PubMed1995

Peroneal nerve repetitive nerve stimulation test: its value in diagnosis of myasthenia gravis and Lambert-Eaton myasthenic syndrome.

We have developed a repetitive nerve stimulation (RNS) technique for the peroneal nerve. Normal limits for the decremental responses for the anterior tibialis and extensor digitorum brevis muscles are 6-21% at the low rate of stimulation and 44-70% at the high rate of stimulation. These values exceed the normal limits for other commonly tested muscles. This may be due to the lower safety factor for neuromuscular transmission for the anterior tibialis and extensor digitorum brevis muscles. We present 4 cases in which the peroneal nerve RNS test was crucial for the diagnosis of the limb-girdle form of MG or LEMS. Thus, we conclude that, in a small number of patients with neuromuscular transmission disorders, the peroneal nerve RNS test is needed for confirmation of disease.

Adult↗
PubMed1995

Light- and electron-microscopic study of substance P-immunoreactive neurons in the guinea pig retina.

Substance P (SP) immunoreactivity in the guinea pig retina was studied by light and electron microscopy. The morphology and distribution of SP-immunoreactive neurons was defined by light microscopy. The SP-immunoreactive neurons formed one population of amacrine cells whose cell bodies were located in the proximal row of the inner nuclear layer. A single dendrite emerged from each soma and descended through the inner plexiform layer toward the ganglion cell layer. SP-immunoreactive processes ramified mainly in strata 4 and 5 of the inner plexiform layer. SP-immunoreactive amacrine cells were present at a higher density in the central region around the optic nerve head and at a lower density in the peripheral region of the retina. The synaptic connectivity of SP-immunoreactive amacrine cells was identified by electron microscopy. SP-labeled amacrine cell processes received synaptic inputs from other amacrine cell processes in all strata of the inner plexiform layer and from bipolar cell axon terminals in sublamina b of the same layer. The most frequent postsynaptic targets of SP-immunoreactive amacrine cells were the somata of ganglion cells and their dendrites in sublamina b of the inner plexiform layer. Amacrine cell processes were also postsynaptic to SP-immunoreactive neurons in this sublamina. No synaptic outputs onto the bipolar cells were observed.

Animals↗
PubMed1995

Multifocal demyelinating motor neuropathy: pathologic evidence of 'inflammatory demyelinating polyradiculoneuropathy'.

We report a case of multifocal demyelinating motor neuropathy in a patient with a 5-year history of progressive, asymmetric, predominantly motor weakness characterized by multifocal progression, multifocal conduction block, and lack of response to steroid therapy. Neuropathologic findings at autopsy showed an "inflammatory demyelinating polyradiculoneuropathy" in the motor cranial nerves and motor roots of peripheral nerves, an extensive deposition of IgG and focal accumulations of IgM in the peripheral nerve motor roots, and loss of motor neurons. These findings clearly document an inflammatory demyelinating polyradiculoneuropathy in multifocal demyelinating motor neuropathy, suggesting a close relation with chronic inflammatory demyelinating polyneuropathy.

Demyelinating Diseases↗
PubMed1994

Early appearance of aging phenomenon in the interdigital nerves of the foot.

To test the hypothesis that the interdigital nerves of the foot are the first to be affected by aging, we studied sensory nerve conduction in the nerves of normal subjects between the ages of 10 and 79, using the near-nerve needle technique. In normal individuals up to the seventh decade we could get sensory CNAPs without any difficulty by 256 averagings. In 10% of the 70-79-year-old group we could not obtain those potentials in some digital or interdigital nerves. Between the 10-49-year-old and 50-79-year-old groups, there was a significant slowing in the sensory NCVs, a significant decline in the amplitude of the sensory CNAPs, and a significant prolongation of the duration of sensory CNAPs for the various interdigital nerves. Thus, our study documented the earlier presence of aging phenomenon in the sensory nerve conduction of the interdigital nerves of the foot compared with the previously reported sensory nerve conduction change with age in the other nerves. We conclude that the "degeneration" of various interdigital nerves of the foot is accelerated from the early 50s on, possibly resulting from the normal aging process.

Action Potentials↗
PubMed1994

Tendon-reflex testing in chronic demyelinating polyneuropathy.

We studied the tendon reflex (T-reflex) in 26 patients with acquired chronic demyelinating polyneuropathy (CDN), including 22 with chronic inflammatory demyelinating polyneuropathy (CIDP). In 7 patients reflexes were brisk or normal on clinical testing. The height adjusted T-reflex was abnormal in 25 (96%) cases, including 6 of 7 patients with brisk or normal reflexes on clinical testing. Mean latency (P < 0.01) and duration (P < 0.05) of the ankle and patellar tendon reflexes were significantly prolonged in the CIDP patients when compared to the controls. Mean latency in the CIDP patients was 152% of normal means. In 7 CIDP patients, the T-reflex latencies were prolonged beyond 150% of normal means. Thus, the T-reflex test is abnormal in a majority of patients with CDN, even in the presence of well-preserved clinical reflexes, and the T-reflex latency is a useful indicator of the presence of a demyelinating peripheral neuropathy in some patients.

Adult↗
PubMed1994

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.

Action Potentials↗
PubMed1994

CYP1A2 activity as a risk factor for bladder cancer.

CYP1A2, CYP2D6 and N-acetyltransferase activities were estimated in 100 patients with bladder cancer and 84 control subjects from measurements of theophylline, metoprolol and isoniazid and their metabolites in urine, respectively. The frequency of occurrence of slow acetylators of isoniazid and poor metabolizers of metoprolol were 16.7% and 1.2% in the control group and 16.3% and 2.0% in the cancer patient group. These differences were not significant. The recovery ratio of 1-methyluric acid(1-MU) from theophylline was significantly higher in patients with bladder cancer than in control subjects(0.340 +/- 0.016 versus 0.260 +/- 0.020, p < 0.05). The 1-MU recovery ratio was a significant, independent risk factor among the metabolic capacities tested as shown by logistic regression analysis, controlling for N-acetylation of isoniazid, hydroxylation of metoprolol, age, sex, and smoking. We concluded that the capacity for 3-demethylation of theophylline, as a reflection of CYP1A2 activity, is significantly associated with increased risk of nonoccupational urinary bladder cancer.

Acetylation↗