Effects of Border Crops and Intercrops on Control of Cucurbit Virus Diseases.

In five field trials over 3 years, control of aphid-transmitted, nonpersistent virus diseases on pumpkin, caused mostly by the potyviruses Watermelon mosaic virus (WMV) and Papaya ringspot virus type-W (PRSV-W), was achieved by intercropping with grain sorghum, as opposed to clean tillage. Reductions in disease incidence ranged from 43 to 96% (P ≤ 0.05). Surrounding pumpkin plots with borders of peanut, soybean, or corn was not effective. Borders of grain sorghum were effective, but disease control was generally less than for the intercrop treatment. Intercropping soybean and peanut with pumpkin reduced disease incidence by 27 to 60% (P ≤ 0.05), but disease control generally was less than for grain sorghum. Peak periods of alate aphid immigration generally preceded virus disease outbreaks by 7 to 14 days. However, alate landing rates, as measured in green tile traps, did not differ among treatments. Marketable yield was not increased by the intercrop treatments, and yield was reduced by up to 50% for the intercrop treatment with grain sorghum in two trials. The use of grass-selective herbicide applied along pumpkin rows, reduced seeding rates of the intercrops, or mowing did not alleviate the adverse effects of competition between pumpkin and the grain sorghum intercrop on yield.

Natural history of median nerve sensory conduction in industry: relationship to symptoms and carpal tunnel syndrome in 558 hands over 11 years.

We evaluated the natural history of median nerve sensory conduction, hand/wrist symptoms, and carpal tunnel syndrome (CTS) in an 11-year longitudinal study of 289 workers from four industries. Twenty hands which had carpal tunnel release surgery were excluded, leaving 558 hands for the primary study group. Overall, the trend was for mean sensory latencies and prevalence of slowing to increase, the prevalence of symptoms to decrease, and the prevalence of CTS to remain unchanged. Among individual hands, nerve conduction abnormalities tended to persist (82% 11-year persistence), while symptoms fluctuated widely (13% 11-year persistence). There was a strong, direct linear correlation between initial severity of slowing and subsequent development of CTS; however, most workers who developed de novo slowing did not develop symptoms or CTS. We conclude that changes in conduction status of the median nerve occur naturally with increasing age and do not necessarily lead to symptoms and CTS.

Longitudinal study of median nerve sensory conduction in industry: relationship to age, gender, hand dominance, occupational hand use, and clinical diagnosis.

As part of a longitudinal study of the cause of carpal tunnel syndrome in industry, we evaluated sensory conduction of the median nerve in relation to age, gender, hand dominance, occupational hand use, and clinical diagnosis. The original 1984 study group consisted of 942 hands of 471 industrial workers, and the follow-up study group in 1989 consisted of 630 hands of 316 (67%) of these same workers. The palmar segmental stimulation technique was employed, and slowing was defined as a maximum latency difference of 0.4 msec or more after adjustment for temperature variation. There was no significant change in the prevalence of slowing between 1984 and 1989 (23% in 1984, 22% in 1989), and slowing was still strongly correlated with increased age but not with gender. Slowing continued to be more prevalent in the dominant hand. Slowing was no longer correlated in any fashion with occupational hand use. The prevalence of probable carpal tunnel syndrome was still strongly correlated with the degree of slowing. Age and hand dominance were more important than any job-related factor in the prediction of slowing after 5 years.

Simple decompression of the ulnar nerve: an alternative to anterior transposition.

Anterior transposition and/or medial epicondylectomy are often considered procedures of choice for ulnar neuropathy at the elbow. Much experience suggests simple decompression to be a comparably effective alternative which involves less trauma, morbidity, and rehabilitation time. The post-operative clinical and electrophysiological results of 52 cases of simple decompression (41 patients) are summarized. Excellent or good clinical results were found in 75% of the nerves. Mean ulnar motor conduction velocities were significantly improved post-operatively, although nerve conduction parameters did not consistently correlate with clinical outcome. The average return-to-work time was 5.1 weeks. The advantages of simple decompression make it the procedure of choice for most cases of ulnar neuropathy.

Obesity as a risk factor for slowing of sensory conduction of the median nerve in industry. A cross-sectional and longitudinal study involving 429 workers.

As part of a longitudinal study of the etiology of carpal tunnel syndrome in industry, we evaluated weight and body mass index (BMI) as risk factors for slowing of sensory conduction of the median nerve. Using nerve conduction studies, we evaluated 858 hands of 429 industrial workers in 1984 and reevaluated 630 hands of 316 of these same workers in 1989. Weight and BMI were strongly and positively correlated with the maximum latency difference (MLD). In 1984 and 1989 the risk for abnormal nerve conduction averaged 3.5-fold and 4.1-fold greater, respectively, in the obese workers than in the slender workers. In stepwise regression analysis for 1989 MLD based on 1984 factors, the BMI was the number one factor selected, followed by age, wrist depth/width ratio, hand dominance, and exercise level. None of three 1984 job-related factors (occupational hand use, duration of employment, or industry) was an independent predictor of 1989 MLD. This study suggests that individual characteristics, not job-related factors, are the primary determinants of slowing of sensory conduction of the median nerve and carpal tunnel syndrome.

Synovial histology in carpal tunnel syndrome.

This study investigates the relationship between idiopathic carpal tunnel syndrome and tenosynovial histology, specifically inflammation. Tenosynovial biopsy specimens from 177 wrists were obtained from patients at carpal tunnel release, and a control group of 19 specimens was also obtained. Inflammation was present in only 10% of the patient specimens and was correlated with only one of the clinical and histologic factors studied, i.e., nerve conduction impairment. Edema, observed frequently (85%), was not correlated with inflammation. Vascular sclerosis was also found consistently (98%) and was correlated with patient age and degree of edema. Edema and vascular sclerosis occurred with significantly greater frequency and severity in the specimens of patients than in the control group. Fibrosis (3%) and synovial hyperplasia (1%) were uncommon findings. It is concluded that tenosynovitis is uncommon in patients undergoing surgery for treatment of idiopathic carpal tunnel syndrome.