Changes in motor unit action potential parameters in monopolar recordings related to filter settings of the EMG amplifier

We studied the effect of different electromyographic amplifier settings on various parameters of motor unit potentials (MUPs) as recorded by the monopolar needle. Of the four filter settings used--2Hz-10kHz, 20Hz-10kHz, 20Hz-2kHz and 500Hz-10kHz--2Hz-10kHz yielded longest duration recordings. Reductions of all parameters of the MUP except for phases and turns were demonstrated with the 500Hz-10kHz filter. No significant differences were noted between recordings obtained with 20Hz-10kHz and 20Hz-2kHz filters. Frequencies below 500Hz were more significant in determining the various parameters of the MUP than were those above 2kHz. Most suitable filter settings for recording MUPs were 2Hz-10kHz and 20Hz-10kHz. Measurements of MUPs were shown to be specific for a given filter setting.

Cloning and expression of the metE gene in Escherichia coli

A lambda-transducing phage was isolated that contains the metE gene. This gene codes for N5-methyl-H4-folate:homocysteine methyltransferase (EC 2.1.1.14), an enzyme that catalyzes the terminal reaction in methionine biosynthesis. A 9.1-kb EcoR1 fragment of this phage, containing the metE gene, was then cloned into pBR325. This plasmid, pJ19, was used to transform Escherichia coli strain 2276, a metE mutant, and restore the MetE+ phenotype. Although the transformed cells produced large amounts of the metE protein in vivo, in vitro studies using pJ19 as template showed low synthesis of the metE protein.

Automatic analysis of the EMG interference pattern

A method is described for the automatic analysis of EMG interference patterns obtained at optional non-controlled force levels. It is a modification of Willison's method of measuring turns and amplitude of the signal. In the method, the mean amplitude is plotted against turns obtained during 300 msec for each of 20 recording sites. Different voluntary strengths are used and a scatter of points is obtained. Confidence limits enclosing these points are constructed for healthy subjects for 4 different muscles with concentric and monopolar electrodes. The normal values differ with age, muscle, sex and electrode. The method is tested on patients with myopathic or neurogenic EMG and a high diagnostic yield is obtained. The method is objective, reproducible, fast and needs relatively small computer facilities.

Survival among women with endometrial cancer: a comparison of estrogen users and nonusers

In order to determine the role of postmenopausal estrogen use in survival of patients with endometrial cancer, we identified, through a population-based tumor registry serving the area, all white women in King County, Washington, aged 50 to 74, who developed endometrial cancer between January, 1975, and April, 1976 (N = 363). Estrogen use prior to diagnosis and survival status were ascertained through personal interview, medical records of private physicians, and registry follow-up data. The 4-year relative survival ratio in estrogen users was 1.05 compared to 0.898 in nonusers. Overall, after adjustment for age, the survival in estrogen users was significantly better than in nonusers (chi 2 = 30.5; p much less than 0.0001). While estrogen use may predispose to an increased incidence of endometrial cancer, it appears that such use does not lead to increased mortality from this condition.

Quality of care in women with stage I cervical cancer

A study was done to assess the quality of care received by women with stage I cervical cancer. Through a population-based registry serving 13 counties of western Washington, including Seattle, we identified all women residents in whom local-stage cervical cancer developed between January 1974 and December 1978 (N=369). The cases were subdivided into stage IA (microinvasive) and stage IB (frankly invasive). Quality of care was defined as optimal or suboptimal at the outset of the study; this definition applied to all cases. In patients with stage IB cervical cancer, striking relationships were found between the quality of care and initial and referral hospital characteristics and physician's specialty. No differences were found, however, in three-year survival between the optimally and suboptimally treated groups.

Stage I vulvar cancer: criteria for microinvasion

Thirty-eight women with stage I epidermoid carcinoma of the vulva were studied retrospectively in an attempt to define the criteria for conservative therapy in early invasive vulvar cancer. Among the 38 women, 23 met the 6 criteria established for early invasive carcinoma of the vulva. In those 23 women, there were no nodal metastases. Depth of stromal invasion correlated strongly with the degree of tumor differentiation and the presence of carcinoma in situ (CIS). Stromal invasion less than 3 mm and presence of CIS were predictive of no involvement of the lymph nodes or endothelial-like space.

Pneumatic ankle tourniquet: clinical and electrophysiologic study

Current orthopedic practice in surgical procedures involving the foot calls for tourniquet of the lower extremity. It is suggested that tourniquet application at the ankle may be equally effective and less traumatic. An experiment to document the sensorimotor and electrophysiologic changes that occur with the use of the pneumatic ankle tourniquet indicated the feasibility of such a procedure. An ankle tourniquet was applied at 250mmHg for 1 hour on 40 healthy adults divided into 2 groups of 20 each. In group 1 there was no temperature control and in group 2 skin temperature was kept constant at 32C. Sensorimotor evaluations were done clinically and electrophysiologically to include proximal and distal motor latencies, conduction velocities and amplitudes of peroneal and tibial nerves, and sensory latencies and amplitudes of sural and medial plantar nerves at fixed points and at fixed times. Final data show no strong indication of difference in nerve parameter abnormalities between subjects of both groups and suggest that change in different parameters of nerve function during tourniquet application is secondary to ischemia and anoxia rather than to mechanical compression.

Results of 100 consecutive femoropopliteal vein grafts for limb salvage

One hundred consecutive patients with femoropopliteal autogenous vein grafts for limb salvage were reviewed five years later. In this group 40% died and 30% of the limbs had been lost at the end of five years. Limb survival correlated best with adequacy of distal run-off, but not with the presence or absence of diabetes. Forty-seven per cent of the grafts were still patent among surviving patients, and when combined with the limbs that were viable despite failure of the original graft, 70% of the limbs were salvaged among the survivors at five years. Temporary graft patency was effective in preserving ischemic tissue by facilitating healing of ulcers or limited amputations. Femoral-popliteal bypass grafting in the presence of advanced ischemia is capable of improving the quality of life for many of these patients.

Femoropopliteal vein grafts for claudication. Analysis of 100 consecutive cases

One hundred consecutive femoropopliteal venous grafts in 85 patients with claudication were followed for five years. At this time, three limbs had been amputated, approximately one quarter of the patients had expired, and 70% of the grafts in surviving patients remained patent. It is concluded that this operation does not appear to increase the risk of amputation and in fact, may lessen it. Moreover, it is associated with minimal risk and generally provides long term relief of claudication, thus enhancing the quality of life in most patients.

Cerebral lateralization of haptic perception: interaction of responses to Braille and music reveals a functional basis

Normally, haptic perception of the left hand surpasses that of the right. But simultaneously playing music into the left (but not the right) ear reverses this superiority. This suggests that the left cerebral hemisphere has full haptic perceptual capability, which is subject to right hemisphere interference unless the latter's attentional mechanisms are engaged by contralateral peripheral stimulation.

A new method for detecting clotting in shunts used for haemodialysis

Thermographic materials were used to monitor the rate of blood-flow through haemodialysis shunts. In an experimental and clinical study it was found that these materials would indicate by a change in colour when blood-flow through a shunt had become diminished or had ceased altogether. As a result clotting episodes were rapidly and easily diagnosed by the patients, and subsequent declotting of the shunts was readily achieved.