Pool cue chalk: a source of environmental lead

Lead compounds are used as coloring agents for numerous products. Two cases of children with elevated blood lead concentrations encountered by the authors suggested that pool cue chalk may serve as a source of environmental lead. The objective of this study was to determine lead content of various brands and colors of pool cue chalk. Atomic absorption analyses were conducted of 23 different types of pool cue chalk for lead content. Three of 23 types of pool cue chalk contained more than 7000 ppm (mg/kg) lead: one manufacturer's green and tangerine chalk and another manufacturer's green chalk. It was concluded that some brands of pool cue chalk contain relatively large amounts of lead and could contribute to childhood lead poisoning.

Deviant olfactory experiences as indicators of risk for psychosis

Olfactory hallucinations, although relatively rare, are reportedly indicative of serious psychopathology and poor prognosis in psychotic patients. This article describes the development of a rating scale for assessing olfactory experiences of psychotic and psychoticlike deviancy. The scale is modeled after Chapman and Chapman's rating scales for other psychoticlike experiences, which have been found to predict psychosis and psychosis-proneness. In a longitudinal study, college students who reported deviant olfactory experiences at their initial assessment (n = 31) exceeded the remaining subjects (n = 477) on DSM-III-R psychosis and on measures of psychosis proneness at a 10-year followup. Furthermore, hypothetically psychosis-prone subjects identified by the Perceptual Aberration and Magical Ideation scales exceeded control subjects on ratings of olfactory experiences at both initial and followup assessments.

P-glycoprotein expression in the squamous cell carcinoma of the tongue base

P-glycoprotein (PGP), which is a product of the multidrug resistance gene (MDR1), is an active transmembrane efflux pump responsible for detoxifying normal cells as well as rendering tumor cells resistant to chemotherapy. It has also been implicated to be expressed by more aggressive cancers. It has not been well described in squamous cell carcinoma of the head and neck. In this investigation, an attempt was made to characterize advanced squamous cell carcinoma of the base of tongue with respect to expression of PGP. Using immunohistochemical techniques two anti-PGP monoclonal antibodies (JSB1 and C494) were used to detect PGP in these lesions, and an attempt was made to correlate levels of PGP staining and various tumor parameters. Usefulness of PGP in predicting survival and time to recurrence was also examined for these advanced lesions. All 33 base of tongue lesions showed staining for PGP with these monoclonal antibodies. This was the first study examining utility of C494 in detecting PGP in squamous cell carcinoma at this site. Increased level of PGP expression was seen in better-differentiated tumors as well as in tumors with diploid DNA. A trend of higher PGP expression and decreased survival emerged. This may represent a true relationship, but inherent heterogeneity of PGP expression within cells cannot be excluded. Both antibodies examined appear to be useful in the investigations of PGP distribution in squamous cell carcinomas of the head and neck sites by immunohistochemical techniques. Prognostic value of the level of PGP expression remains to be seen.

Task difficulty and cognitive deficits in schizophrenia

Investigators of schizophrenic cognition often produce 2 or more tasks of differing difficulty levels by manipulating a variable that affects the accuracy of both normal and schizophrenic individuals; the investigators find that the variable also affects the difference between the groups in accuracy and conclude that the variable taps a schizophrenic differential deficit. An alternative hypothesis is that task differences in true-score variance artifactually produce the finding. For free-response tasks, group differences tend to be larger when difficulty is near 50%. The authors illustrate a new method of controlling this artifact by selecting items for hard and easy tasks on opposite sides of 50% difficulty and equidistant from it. Using this design with an anagram task, they found that schizophrenic and normal individuals differ no more on hard anagrams than on easy ones, and they propose the design for testing hypotheses concerning schizophrenic deficit on tasks that differ in difficulty.

Treatment of experimental frostbite with pentoxifylline and aloe vera cream

OBJECTIVE

To compare the therapeutic effects of systemic pentoxifylline and topical aloe vera cream in the treatment of frostbite.

DESIGN

The frostbitten ears of 10 New Zealand white rabbits were assigned to one of four treatment groups: untreated controls, those treated with aloe vera cream, those treated with pentoxifylline, and those treated with aloe vera cream and pentoxifylline.

MAIN OUTCOME MEASURES

Tissue survival was calculated as the percent of total frostbite area that remained after 2 weeks.

RESULTS

The control group had a 6% tissue survival. Tissue survival was notably improved with pentoxifylline (20%), better with aloe vera cream (24%), and the best with the combination therapy (30%).

CONCLUSION

Pentoxifylline is as effective as aloe vera cream in improving tissue survival after frostbite injury.

Task difficulty and cognitive deficits in schizophrenia

Investigators of schizophrenic cognition often produce 2 or more tasks of differing difficulty levels by manipulating a variable that affects the accuracy of both normal and schizophrenic individuals; the investigators find that the variable also affects the difference between the groups in accuracy and conclude that the variable taps a schizophrenic differential deficit. An alternative hypothesis is that task differences in true-score variance artifactually produce the finding. For free-response tasks, group differences tend to be larger when difficulty is near 50%. The authors illustrate a new method of controlling this artifact by selecting items for hard and easy tasks on opposite sides of 50% difficulty and equidistant from it. Using this design with an anagram task, they found that schizophrenic and normal individuals differ no more on hard anagrams than on easy ones, and they propose the design for testing hypotheses concerning schizophrenic deficit on tasks that differ in difficulty.

Computing conditional recombination probabilities given marker information

When a parent is homozygous, it is not possible to determine directly whether offspring share an allele identical by descent (IBD) from that parent. However, an IBD probability can be computed using information from linked loci where the parent is heterozygous. To solve this problem for the phase-known case, probability equations and a computer program were developed for efficient computation of conditional probabilities under a Sturt model of chiasma interference. Data are analyzed and contrasted with and without taking interference into account. The effect of failing to account for interference is very small, but the computational cost is also small.

Effect of dietary calcium concentrations during gestation and lactation in the sow on milk composition and litter growth

This study evaluated the effects of diets containing varying amounts of Ca on milk composition and litter characteristics of sows. Yorkshire sows were fed one of the following diets: low Ca (.38%; n = 5), standard Ca (.75%; n = 5), or high Ca (1.12%; n = 4). Diets were fed from d 42 of gestation to d 42 of lactation. Milk was collected on d 7 +/- 1, 21 +/- 1, and 42 +/- 1 of lactation. Lactose was greater (6.4%, P < .05) in milk from sows fed low Ca than in those fed standard (5.5%) or high (5.8%) Ca, but only on d 7 of lactation. No treatment effect or time x treatment interaction was detected for total protein or casein concentrations. Calcium increased (P < .05) over time irrespective of treatment. There was an increase (P < .05) in ADG on d 7 in pigs from high-fed (.28 kg) and low-fed sows (.20 kg) compared with those from standard-fed sows (.13 kg). In conclusion, body Ca is so physiologically regulated that minor dietary alterations have little overall effect on milk composition. Alterations in ADG for pigs, especially from sows fed high Ca, warrant further investigation.