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.

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.

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.

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.

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.

Surface roughness evaluation via ultrasonic scanning

Despite extensive applications of ultrasonic waves to various nondestructive testing and evaluation of materials, scattering of focused ultrasonic waves due to surface roughness has not been fully investigated. This paper presents an analytical and experimental evaluation of surface roughness measurement using focused ultrasonic beams. The characteristics of focused ultrasonic waves are analyzed by using the impulse response method with a sine-modulated Gaussian pulse as source. First, the beam profile in the focal plane of the focused ultrasonic transducer is analyzed both numerically and experimentally. Second, peak amplitude distribution and reflected waveforms from a flat surface with various incident angles are analytically generated and compared with experimental results. Then, the peak amplitudes of the ultrasonic waves reflected from cusped surfaces which are easily found among machined surfaces are analyzed and compared with experimental data for the first time. The analysis shows good agreement between analytical and experimental results. The excellent correlation between the measurements using a profilometer and the proposed ultrasonic system demonstrates a good potential for surface roughness measurement by ultrasonic sensing.

Quantitation of tendon reflexes in normal volunteers

Ankle (ATR), patellar (PTR) and triceps (TTR) T-reflex responses were recorded in 48 limbs of 24 normal volunteers by delivering tendon taps with a hand operated electronic hammer. Latency to the onset of the triggered response, peak to peak amplitude and duration of the wave were measured after several repetitions. In all individuals, ATR and PTR were observed, while in 27% of limbs, TTR was absent. Shortest latency and duration of the elicited response were chosen to calculate normal means. Side differences were also evaluated. As amplitude showed a marked interindividual and side to side variation, lowest recorded value was selected to represent the lower limit of normal. Age, height, and leg length showed a good correlation with minimum ATR latency (p < 0.001). PTR latency correlated significantly with age, height, (p < 0.001) and thigh length (p < 0.001). No significant correlation existed between age, height, arm length and TTR latency (p > 0.01). In conclusion, ATR and PTR are acceptable tests in clinical practice, whereas TTR is not reliable, as it is technically difficult to elicit in some normal individuals.

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.

Temperature effects on nerve conduction studies in patients with carpal tunnel syndrome

This study was done to evaluate the effect of rising temperature on nerve conduction parameters in 22 patients with carpal tunnel syndrome (CTS). We wanted to find out whether diseased nerves responded to temperature rise in a different manner from normal controls. For this purpose a group of 20 healthy individuals were also tested. With rising temperature motor nerve conduction velocities increased, whereas latencies, amplitudes and duration of the compound muscle action potential decreased in both groups. These changes were not statistically significant between the two groups. Sensory nerve conduction parameters yielded basically similar findings except for a significantly smaller reduction in amplitude of the compound nerve action potential (CNAP) in the CTS group (p < 0.005). We conclude that there is a different response in the sensory CNAP amplitude between normal and CTS groups, but the same nerve conduction correction formulae for temperature can be used in CTS patients as in normal individuals in the event of low skin temperature.

Primary respiratory failure as the presenting symptom in Lambert-Eaton myasthenic syndrome

Myasthenia gravis can present with rapid respiratory failure as the first manifestation of disease. In the Lambert-Eaton myasthenic syndrome (LEMS), such a manifestation has rarely been reported. We are reporting a patient who developed respiratory failure as the first manifestation of LEMS without associated carcinoma.

Eosinophilic cystitis caused by vesical sparganosis: a case report

We report a case of eosinophilic cystitis caused by vesical sparganosis. The patient had a history of eating raw frogs and presented with a mass in the bladder associated with peripheral eosinophilia and increased serum antibody titer against sparganum. Pathologically, a characteristic sinuous necrosis representing worm tracks was noted with massive diffuse infiltration of eosinophils in the wall of the bladder. The serum titer of sparganum-specific antibody returned to normal after surgical resection of the lesion. This finding emphasizes the importance of suspecting parasitic origin in cases of eosinophilic cystitis with a history of raw meat ingestion in endemic areas.

Rimmed vacuoles of inclusion body myositis and oculopharyngeal muscular dystrophy contain amyloid precursor protein and lysosomal markers

Rimmed vacuoles are small areas of focal destruction of muscle fibres, found in inclusion body myositis, oculopharyngeal muscular dystrophy and other muscle disorders. They are known to contain amyloid proteins, probably of beta-amyloid type. We examined rimmed vacuoles immunohistochemically in 12 patients with inclusion body myositis and two patients with oculopharyngeal muscular dystrophy with antibodies to beta-amyloid precursor protein and cathepsin B and D. We found evidence for the presence of all these markers in rimmed vacuoles. These results confirm the presence of beta-amyloid in rimmed vacuoles, and provide additional support for the hypotheses that rimmed vacuoles are of lysosomal origin and that lysosomes are probably important in the metabolism of amyloid precursor protein.

A new mtDNA mutation in the tRNA(Lys) gene associated with myoclonic epilepsy and ragged-red fibers (MERRF)

Myoclonic epilepsy with ragged-red fibers (MERRF) has been associated with an A--G transition at mtDNA nt 8344, within a conserved region of the tRNA(Lys) gene. Although the 8344 mutation is highly prevalent in patients with MERRF, it is not observed in 10%-20% of the cases, suggesting genetic heterogeneity. We have sequenced the tRNA(Lys) gene of five MERRF patients lacking the common 8344 mutation. One of these showed a novel T-->C transition at nucleotide position 8356, disrupting a highly conserved base pair in the T psi C stem. The mutant mtDNA population was essentially homoplasmic in muscle but was heteroplasmic in blood (47%). Neither 20 patients with other mitochondrial diseases nor 25 controls carried this mutation. These findings suggest that tRNA(Lys) alterations may play a specific role in the pathogenesis of MERRF syndrome.

Vasculitic neuropathy mimicking Guillain-Barré syndrome

Vasculitic neuropathy classically manifests as a subacute mononeuritis multiplex or polyneuropathy. Patients with a Guillain-Barré syndrome (GBS)-like presentation are usually not considered to have an underlying vasculitis. We describe 2 patients with rapidly progressive areflexic paralysis that was initially diagnosed as GBS, in whom vasculitic neuropathy was found histologically.

"Chronic sensory demyelinating neuropathy": chronic inflammatory demyelinating polyneuropathy presenting as a pure sensory neuropathy

The clinical electrophysiological and histological features of 10 cases of "chronic sensory demyelinating neuropathy" (CSDN) are reported. This entity is characterised by: 1) subacute or chronic progression; 2) pure sensory neuropathy; 3) high spinal fluid protein in the majority of cases; 4) electrophysiological evidence of demyelination affecting motor as well as sensory nerve fibres; 5) demyelination on sural nerve biopsy and 6) good response to immunotherapy in progressive phase. It is believed that this entity represents chronic inflammatory demyelinating polyneuropathy (CIDP) presenting as pure sensory neuropathy.

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.

Chronic limb-girdle myasthenia gravis

The existence of chronic "limb-girdle" form of myasthenia gravis (MG) has been questioned. We report here 12 such patients (10 women and two men) who constituted 3.8% of 314 MG patients in our study. The duration of disease ranged from 4 months to 7 years before the diagnosis. In almost all cases, the initial diagnosis was other than MG. None of the patients had any oculobulbar weakness. Acetylcholine receptor antibody was positive in five cases, although not all in the first assay. Repetitive nerve stimulation test was positive in all cases, although not necessarily the first time. Single-fiber EMG was positive in 11 cases. All patients responded to acetylcholinesterase inhibitors, and two thirds underwent immunotherapy. Diagnosis of limb-girdle MG requires a strong index of suspicion.