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Here we report that a synthesised form of a naturally occurring chemical (a butenolide, 3-methyl-2 H-furo[2,3- c]pyran-2-one) found in smoke can stimulate seedling emergence of the economically important weed species Avena fatua L. (Poaceae), Arctotheca calendula (L.) Levyns (Asteraceae), Brassica tournefortii Gouan (Brassicaceae), and Raphanus raphanistrum L. (Brassicaceae) under field conditions at rates equivalent to 2–20 g/ha a.i. The butenolide also stimulates germination of freshly collected seeds from wild populations of these species, as well as those of Sisymbrium orientale L. (Brassicaceae), Hordeum leporinum Link (Poaceae) and Echium plantagineum L. (Boraginaceae) under laboratory conditions, consistently greater than that of smoke water. Experiments using B. tournefortii seeds collected from several locations across Western Australia and in different growing seasons found that these factors significantly influence the butenolide response, implying a role of the maternal environment in seed germination/dormancy characteristics. This research highlights the potential of butenolide as an agent for broad acre weed control and land restoration. [ABSTRACT FROM AUTHOR]

The hearing of 346 babies taken largely from a neonatal intensive care unit has been tested by otoacoustic emissions and brain stem electric response audiometry. A total of 336 (97%) of the babies have been followed up by hearing tests from the age of 8 months. The otoacoustic emission test has been found to be practical with a mean test time of 12.1 minutes compared with 21.0 minutes for brain stem electric response. An otoacoustic emission was recorded bilaterally in 274 (79%) babies. Twenty of the 21 surviving infants who failed brain stem electric response in the neonatal period did not produce an emission. It is concluded that the otoacoustic emission test would make a good first screen to be followed by the brain stem electric response if no otoacoustic emission was present. There is poor agreement between the test results in the neonatal period and those of the follow up period, however, indicating the need for continuous monitoring of those babies failed by brain stem electric response. [ABSTRACT FROM AUTHOR]

The use of site assessment indices to guide agricultural phosphorus (P) nutrient management has been widely adopted in the United States. This study compares P-index ratings from 12 southern states (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, and Texas) on fields representing three dominant southern agricultural systems: upland pasture, upland cornfield, and artificially drained field. The structure of each P-index varied enough to produce widely divergent ratings when applied to similar scenarios where individual factors (such as soil test P, poultry broiler litter application rate, or buffer absence or presence) were adjusted across a broad range of P-index input values. Variation in P-index ratings was the unique combination of each state's selected factors, weighting of the factors, and factor combination (added, multiplied, or a mixture of both addition and multiplication). Although the flexibility of and differences among the southern states' P-indices result in dramatically diverse P-index ratings for the same set of conditions, the diversity in P-index construction allows for indices designed to match individual state conditions and concerns. The substantial differences in P-index results identified in this survey highlight the need for close coordination between states in revising Pindices if they are to be applied across state lines. [ABSTRACT FROM AUTHOR]

We describe 12 patients with a diagnosis of carpal tunnel syndrome in whom carpal tunnel release was unsuccessful and another neurologic disorder was diagnosed subsequently. Final diagnoses included polyneuropathy, radiculopathy, motor neuron disease, spondylotic myelopathy, syringomyelia, and multiple sclerosis. Sources of error by the electromyographer and treating physician were identified. Care must be taken to avoid an inappropriate carpal tunnel operation when clinical or electrodiagnostic features are atypical.

We describe a 62-year-old woman in whom skin biopsies verified the clinical diagnosis of granuloma annulare and neurologic and electromyographic studies confirmed the neurologic diagnosis of carpal tunnel syndrome. Short-term treatment with a low dose of chlorambucil taken orally was prescribed. Within weeks, the granuloma annulare had disappeared, and the clinical symptoms of carpal tunnel syndrome had resolved. Electromyography showed variable improvement at the end of treatment and resolution at 9-month follow-up. Our case confirms that short-term treatment of granuloma annulare and associated carpal tunnel syndrome with low-dose chlorambucil is successful.

To establish the best strategy for transmitting speech-derived information via a single tactile channel, measurements were made on the perception of frequency- and/or amplitude-modulated pulse-train stimuli, with a comparison of the electrotactile and vibrotactile modalities. In one experiment, vibrotactile perception of 2-oct step changes in stimulus frequency was found to be significantly better than electrotactile on a time-scale appropriate for the transmission of speech features (e.g., with practiced subjects, information transfer of 69% with 200-ms vibrotactile stimuli, 32% with 200-ms electrotactile stimuli). Perception of step changes in stimulus amplitude was similar in the two modalities when changes in amplitude were tailored to match the different dynamic ranges available. In a second experiment, vibrotactile-perception of voice fundamental frequency with various codings was investigated. Both experiments showed information transfer for vibrotactile stimuli to be greater when frequency and amplitude modulation were used together rather than with one or the other in isolation (sentence-stress identification scores: 66% for FM stimuli, 69% for AM stimuli, 80% for FM/AM stimuli). It is concluded that frequency- and amplitude-modulated vibratory stimulation is a good choice in a practical device for the profoundly hearing impaired.

With use of a comprehensive medical records-linkage system, we identified the comorbid conditions and risk factors in the residents of Rochester, Minnesota, who had a diagnosis of carpal tunnel syndrome during 1961 through 1980. In 43.2% of the 1,016 patients, no associated conditions were found on review of the medical records, whereas associated conditions were documented in 56.8%. The most frequent of these conditions were Colles' fracture, rheumatoid arthritis, hormonal agents or oophorectomy (or both), diabetes mellitus, and, among men, occupations that involved excessive use of the hands. Rheumatoid arthritis, diabetes mellitus, and pregnancy were significantly more frequent among the study patients with carpal tunnel syndrome than in the general population of Rochester, Minnesota. The standardized morbidity ratio was 3.6 for rheumatoid arthritis, 2.3 for diabetes mellitus, and 2.5 for pregnancy. The population attributable risk for pregnancy among women 15 to 44 years old was 7.0%. The standardized morbidity ratio for polymyalgia rheumatica was not significantly increased.

Liver microsomes from phenobarbital-treated rats of four inbred strains expressing distinct allelic variants of cytochrome P450IIB1 were analyzed. The Wistar Munich (WM) strain exhibited 5- to 10-fold lower androstenedione 16 beta-hydroxylase activity (a specific P450IIB1 marker) than the Lewis, Wistar Kyoto, and Wistar Furth strains. The androstenedione 16 beta-hydroxylase in the WM liver microsomes was refractory to inactivation by N-(2-p-nitrophenethyl)chlorofluoroacetamide, a selective P450IIB1 inactivator in the other three strains. Purified P450IIB1-WM was insensitive to the inactivator and exhibited 5-fold lower androstenedione 16 beta-hydroxylase, testosterone 16-hydroxylase, and 7-ethoxycoumarin deethylase activities but the same benzphetamine demethylase activity and slightly higher androstenedione 16 alpha-hydroxylase activity than a P450IIB1 purified from outbred Sprague-Dawley rats, which appears to correspond to the form in Lewis rats. The stereoselectivity of androstenedione 16-hydroxylation catalyzed by P450IIB1-WM (16 beta-OH:16 alpha-OH = 1.4) is thus distinct from that (16 beta-OH:16 alpha-OH = 12-15) of other P450IIB1 preparations described. A cDNA encoding P450IIB1-WM was cloned and sequenced, revealing a single amino acid substitution (Gly-478----Ala) compared with the published sequence (Fujii-Kuriyama, Y., Mizukami, Y., Kawajiri, K., Sogawa, K., and Muramatsu, M. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 2793-2797). Heterologous expression of P450IIB1 and P450IIB1-WM confirmed the striking difference in androstenedione metabolite profiles, strongly implicating the involvement of Ala-478 in defining the distinctive catalytic properties of P450IIB1-WM.

Transverse sections of the sural nerve of a 46-year-old woman without neuropathic symptoms or abnormalities on nerve conduction, electromyography, or computer-assisted sensory examination contained minute regions with large onion bulbs intermingled with normal-appearing myelinated fibers and surrounded by fields of normal myelinated fibers. This woman's 19-year-old daughter had long-standing hypertrophic neuropathy with diffusely distributed large onion bulbs. Computer-imaging reconstruction of myelinated fibers and teased myelinated fiber studies of fascicles containing focal regions with onion bulbs of the mother's nerve provided evidence that onion bulbs surrounded atrophic axons with short internodes and demyelination. This is the least expression for inherited neuropathy which has been reported. These findings therefore suggest that an inherited neuropathy may be minimally expressed by a pathologic alteration of only selected neurons (axons).

A young woman had chronic symptoms of "burning feet" but no clinical or neurophysiologic findings of neuropathy. These symptoms were aggravated by warmth and ameliorated by cooling. Extensive pathologic grading of teased sural nerve fibers, however, provided suggestive evidence of a low-grade pathologic abnormality. Other kin were discovered to have similar symptoms in an autosomal-dominant pattern, and some of these relatives had evidence of a subclinical sensory neuropathy. From this experience, we infer that a mild subclinical neuropathy may underlie the symptom of burning feet; burning pain of the feet may be dominantly inherited; hereditary sensory neuropathy may, therefore, manifest with only positive symptoms of burning pain, restless legs, and lancinating pain, rather than with mutilating acropathy, neurotrophic arthropathy, or severe distal sensory loss as is usually reported; and temperature may modulate physiologic mechanisms related to the experience of burning pain.

To answer the question, "Does long-distance running injure nerves of the feet and legs?" we invited the 25 members of the Rochester Track Club who had run the greatest number of miles in their lifetime to participate in a study that involved neurologic examination, determination of detection thresholds of touch-pressure, vibratory, and cooling sensations of the foot, and evaluation of nerve conduction. None of the runners had clinical symptoms or signs of peripheral neuropathy. Most of them reported having had toe and foot injuries, sometimes associated with short-lived sensory symptoms. A computer-assisted sensory evaluation of the detection threshold for vibratory sensation of the toe revealed slightly, but significantly, higher values in the runners in comparison with age- and sex-matched control subjects. Similarly, small, but statistically significant, differences were also observed for some attributes of nerve conduction in the leg and foot nerves of the runners. These results suggest that long-distance running causes multiple small injuries to the toes and feet, which lead to measurable differences in the detection threshold for vibratory sensation and in nerve conduction but not to overt neuropathy. The trivial subclinical neuropathic deficits we noted are readily offset by the assumed health and recreational benefits of running.

A 22-year-old female, with multiple polyposis of the colon and two central nervous system tumors, also suffered from recurrent basal cell carcinoma. The purpose of this report is to alert physicians to the possibility that basal cell carcinoma occurring at an unusually young age may be another manifestation of the familial polyposis syndromes.

MR brain scans, spinal fluid electrophoresis, and evoked responses were obtained in 10 adult patients with isolated spinal cord symptoms diagnosed as possible multiple sclerosis (MS) according to the McAlpine criteria. Typical lesions of MS were found on T2-weighted MR images in six patients. Spinal fluid abnormalities were found in four. Visual-evoked responses or brainstem auditory-evoked responses were abnormal in three. MR in conjunction with spinal fluid analysis supported the diagnosis of MS in eight of 10 patients. Evoked responses appeared less sensitive than MR in identifying subclinical lesions in this population.

To explore the benefits that students may derive from assuming responsibility for the medical care of people in isolated communities under a minimum of supervision, two volunteer third-year medical students spent the summer of 1964 caring for 1600 Indians and Metis at Wabasca, Alberta. They worked closely with the local public health nurse and a Catholic nursing sister who maintained a small hospital. Considerable experience was gained in preventive medicine and in the diagnosis and management of a wide variety of illnesses, using basic clinical skills and minimal laboratory facilities. The pressure of responsibility was particularly beneficial. It provided a potent impetus to learn and perfect skills in clinical medicine and basic therapeutics. Visits by an interested clinician every two to three weeks provided the optimum combination of responsibility and supervision. The existence of some local health organization was considered helpful.

In a wide variety of learning experiments, cumulated measures of performance turn out to be a power function of practice time or number trials, typically with an exponent between 1 and 2. The effects of various conditions on the course of learning can frequently be described in terms of the two constants of the function.