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J F Smith

Publications and source records attributed to J F Smith.

280 records · Page 16Linked to original sources
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Comparative neurovirulence of attenuated and non-attenuated strains of Venezuelan equine encephalitis virus in mice.

A candidate live-attenuated virus vaccine for protection against Venezuelan equine encephalitis (VEE) (designated V3526) was tested in mice to measure the magnitude, duration, and kinetics of virus replication in the blood and the central nervous system and its phenotypic stability after multiple passages in mice and cell culture. All results were compared to parallel experiments with parental virus and the existing VEE virus vaccine, TC-83. Maximum virus titers in the brains of V3526-inoculated mice were between 10- and 100-fold less than those observed in brains of mice inoculated intracranially (i.c.) with either the parental virus or TC-83. Neither V3526 nor TC-83 was lethal in BALB/c mice inoculated i.c.. However, mice inoculated with TC-83 developed acute symptoms lasting at least 14 days. In contrast, i.c. inoculation of TC-83 was uniformly lethal for C3H/HeN mice. V3526 was avirulent in both BALB/c and C3H/HeN mice after i.c. inoculation. The virulence characteristics of V3526 remained unchanged after five serial i.c. passages in mouse brains or after five cell culture passages. Finally, pathologic changes induced after i.c. inoculation of V3526 were consistently less severe and of shorter duration than those observed in TC-83-inoculated mice. Based on these results, V3526 is stable and appears to be significantly less neurovirulent in mice than TC-83.

Animals↗
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Analysis of zearalenone and alpha-zearalenol in urine of ruminants using gas chromatography-tandem mass spectrometry.

The present paper describes a sensitive procedure for quantitative analysis of the Fusarium mycotoxins zearalenone and alpha-zearalenol in urine of ruminants. Extraction is done with an octadecyl (C18) column and cleanup with a silica column providing a preparation that is analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The trimethylsilyl ether derivatives of zearalenone and alpha-zearalenol yield molecular ions with m/z 462 and 536, respectively. These ions are selected in the first mass analyzer and then fragmented in a collision cell to give characteristic daughter ions (m/z 151, 333, 318, and 446). The method is known as multiple reaction monitoring (MRM). Elimination of chemical background noise by selecting proper fragment ions produces chromatograms in which identification and quantitation in a biological matrix is possible. The method was tested with sheep urine from an experimental feeding trial and was used to confirm natural mycotoxicosis of cows affected with zearalenone. Zearalenone (1 ppb) and alpha-zearalenol (14 ppb) were found in 2 different cow urine samples. The detection limit for both zearalenone and zearalenol is 1 ppb (1 ng/mL) in urine and is linear between 1 and 20 ppb for the former and 1 and 10 ppb for the latter.

Animals↗
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Recurrent acute myelomonoblastic leukaemia presenting as a red eye.

A 68-year-old man was first diagnosed as having acute myelomonoblastic leukaemia on March 17, 1983. After two remissions with treatment, he suffered a further relapse, which caused him to present with a red eye, visual failure, and oedema of the right optic nerve head. Examination of cerebrospinal fluid that was obtained on lumbar puncture demonstrated an acute central nervous system relapse. Computed tomographic scanning led to the diagnosis of leukaemic infiltration of the optic nerve. Systemic and intrathecal treatment by appropriate chemotherapy and by orbital radiotherapy led to resolution of the clinical problem.

Aged↗
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Peer profile.

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Humans↗
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Chalazion.

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Cysts↗
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The validity of the prone leg check as an estimate of standing leg length inequality measured by X-ray.

OBJECTIVE: To determine if prone leg length measurements for inequality are valid to estimate standing X-ray measured differences. DESIGN: Leg length inequality (LLI) was measured, in millimeters, with each patient prone and with a standing X-ray, by an experienced chiropractor. Correlation between the two was calculated, and dependent t test performed. SETTING: Private chiropractic practice. PARTICIPANTS: The first 50 new patients with low back pain (LBP) who were X-rayed were included in the study. RESULTS: Correlation between the two variables was 0.71. Standard error of estimation was 5.4 mm. In 54% of subjects, the prone measurement was within 3 mm of the X-ray LLI; in 12%, however, opposite legs were identified as being "shorter" between the two methods. In 76% of patients, prone measurements were within 6 mm of X-ray, but there was 12-mm difference between the two measurement methods in 8% of the comparisons. CONCLUSIONS: Despite positive correlation, prone leg length measurements for inequality are not entirely valid estimates of standing X-ray differences. Large differences between prone and X-ray measurements in some cases indicate that one should be cautious when using the prone method alone to estimate leg length discrepancy. Additional research is needed to determine the causes of measurement differences between the two methods. Other methods for estimating standing leg length differential must be developed and evaluated for validity.

Adolescent↗