Magnetic resonance imaging in acute physeal injuries

Magnetic resonance imaging (MRI) permits noninvasive evaluation of the cartilage of the growth plate and epiphysis. This paper reports three cases where MRI was used to supplement conventional radiography in the assessment of acute physeal injuries. In the first patient, MRI was used for postoperative assessment of a radial neck fracture, avoiding further surgical exploration. In the second case, MRI was compared with ultrasonography in the diagnosis of proximal humeral epiphyseal separation in a neonate. In the third case MRI and computed tomography were compared in evaluation of a Salter-Harris type 4 distal femur fracture. In all cases MRI was diagnostic. MRI is the investigation of choice in acute complex physeal injuries, and is particularly appropriate for use prior to the appearance of the secondary ossification center.

Ornithine decarboxylase, fatty acid synthetase, and lipid levels in selected organs of the postnatal developing male miniature pig

Ornithine decarboxylase (ODC) and fatty acid synthetase (FAS) activities were determined in tissues from male neonate and juvenile miniature swine (Hormel-Hanford strain) at various ages. ODC activity was measured in liver, brain, kidney, pancreas, and spleen at one day and at 1, 4, 8, 12 and between 24 and 32 weeks. Hepatic FAS activity, total lipid, triglyceride, and total cholesterol were measured at 2, 8, 16, and 32 weeks. Generally, tissue ODC activity was highest in the spleen at all ages. Three postnatal patterns of ODC activity were observed for the different organs. The mean values of FAS activity, total lipid, and cholesterol were highest at 8 weeks compared to other sampling periods.

Body and organ growth of the developing Hormel-Hanford strain of male miniature swine

As part of a larger study designed to characterize the early developmental stages of the Hormel-Hanford strain miniature pig, whole body, brain, kidney, liver, pancreas and spleen from male animals were examined for weight increases from one to 196 days, the approximate age of maturity. At 196 days, body weights had increased to 82.5 times the weight at day 1; increases in organ weights were greatest for spleen, less and similar for kidney, liver and pancreas, and the least for brain. Little change in relative organ weights was noted, except for the brain where an almost steady decrease occurred starting from 7 days after birth.

Estrogen replacement therapy and memory in older women

OBJECTIVE

To study the relationship between estrogen hormone replacement therapy and recall of proper names and words in cognitively intact older women.

DESIGN

A case-control study using subjects matched on age and education.

PARTICIPANTS

From a group of 278 older (age range 55 to 93 years) community-dwelling women volunteers for memory research, 72 older women taking estrogen replacement therapy were matched on age and education with a group of 72 women not taking estrogen.

MEASUREMENTS

Dependent measures were performances on: a proper name recall test and a word recall test.

RESULTS

Proper name recall was significantly better in those receiving estrogen (mean = 4.3; SD = 3.3) than in those not receiving estrogen (mean = 3.1; SD = 2.5), P = 0.01. There was also significantly greater variance in the name recall scores of the group taking estrogen than in the group not taking estrogen. For word recall, there was no significant difference between those subjects taking estrogen (mean = 6.4; SD 3.8) and those not taking estrogen (mean = 5.8; SD 3.7), P > 0.10.

CONCLUSIONS

Estrogen use was associated with enhanced recall of proper names. Previous failures to find differences associated with estrogen use may reflect the memory measures used or an increased inter-individual variability of the estrogen-taking group, as was observed in the present study. Interpretation of these results should be tempered by their retrospective nature.

Acute and 8-hour effects of alcohol (0.08% BAC) on younger and older pilots' simulator performance

This preliminary study examined the acute and 8-hour effects of alcohol at a target peak BAC of 0.08% on pilot performance. Fourteen younger (mean age 27.6 years) and fourteen older (mean age 60.3 years) pilots flew a Frasca 141 simulator in a scenario that included ATC communications and emergencies. Plots were tested during an alcohol and placebo condition at three timepoints: predrink, acute intoxication, and 8 h postdrink. Of eight performance measures, two showed statistically significant effects related to alcohol. First, cockpit monitoring was poorer when pilots were intoxicated, with recovery at 8 h. Second, younger pilots made more communication errors under the influence and there was no significant recovery at 8 h. Older pilots made more communication errors than younger pilots, but possibly because of methodological problems, older pilots' communication performance was not significantly impaired by alcohol. These results provide direction for future research.

Eye movement impairment and schizotypal psychopathology

OBJECTIVE

Eye movement dysfunction in relation to a smooth pursuit task has been documented in schizophrenic patients and in patients with the related personality disorder, schizotypal personality disorder. To investigate which quantitative measures are associated with the eye movement dysfunction and whether the dysfunction is more related to the psychotic-like or the deficit-like symptoms of schizotypal personality disorder, ratings of eye movements in several groups of subjects were compared.

METHOD

The study groups consisted of 26 patients with schizotypal personality disorder, 42 patients with other personality disorders (22 who also had two or more schizotypal personality traits and 20 who had fewer than two), and 37 normal comparison subjects. Smooth pursuit eye tracking of sinusoidal and constant velocity targets was recorded by an infrared eye tracking system. Two raters evaluated pursuit gain and large and small saccades in the direction of the target and in the direction opposite to that of the target (quantitative ratings) and constant velocity (qualitative rating).

RESULTS

Patients with schizotypal personality disorder and patients with other personality disorders and two or more schizotypal traits, but not those with fewer than two schizotypal traits, had significantly poorer qualitative ratings of tracking than the normal comparison subjects. Neither gain nor any of the saccadic measures significantly differed between groups. The number of large saccades in the direction of the target was the only quantitative variable that predicted low qualitative ratings. Qualitatively poor tracking was associated with the deficit-like, but not the psychotic-like, symptoms of schizotypal personality disorder.

CONCLUSIONS

Patients with schizotypal personality disorder demonstrate qualitatively poorer tracking than comparison groups, and the impaired tracking is associated with deficit-like symptoms.

The effect of apomorphine, MK-212 (6-chloro-2-[1-piperazinyl]-pyrazine) and placebo on smooth pursuit gain and corrective saccades in normal subjects

The effects of apomorphine (0.01 mg/kg SC) a direct-acting dopamine (DA) agonist, MK-212 (6-chloro-2-[1-piperazinyl]-pyrazine) (20 mg PO), a direct-acting serotonin (5-HT) agonist, and placebo on smooth pursuit eye movements were evaluated in 10 to 12 normal volunteers. Smooth pursuit was tested just prior to administration of either apomorphine, MK-212, or placebo (on separate days), and then repeatedly tested at 30 min intervals for two hours after dose administration. The smooth pursuit targets were a series of predictable, constant velocity ramps with velocities of 5 degrees/sec (slow target) and 20 degrees/sec (fast target). Eye movements were recorded with infrared oculography, and the following six measures were obtained; steady-state gain (slow-target-gain; fast-target-gain), corrective catch-up saccade (CUS) rate (slow-target-CUS-rate; fast-target-CUS-rate), and CUS amplitude (slow-target-CUS-amplitude; fast-target-CUS-amplitude). The placebo test yielded a statistically significant monotonic decrease over time in slow-target-gain and corresponding increase in slow-target-CUS-rate, but no effects of placebo were noted for the fast target. Apomorphine injection produced a marked reduction in both slow-target-gain and fast-target-gain at 30 min, returning to baseline thereafter. Apomorphine injection also produced a statistically significant increase in slow-target-CUS-amplitude. Ingestion of MK-212 produced a statistically significant increase in slow-target-gain and fast-target-gain as well as a corresponding decrease in slow-target-CUS-rate and fast-target-CUS-rate at 90 min or 120 min. There was evidence that the decline in slow-target-gain after apomorphine was associated with side-effects such as sleepiness, but the decline in fast-target-gain was not related to side-effects. The improved smooth pursuit performance after MK-212 was not related to side-effects. The data suggest that serotoninergic stimulation can improve smooth pursuit performance, whereas dopaminergic stimulation worsens this performance.

Focal fibrocartilaginous dysplasia and tibia vara: a case report

A 2-year-old black boy with focal fibrocartilaginous dysplasia is described with illustrations of the typical radiographic appearances supplemented by computed tomographic and magnetic resonance images. Since this rare condition is self-correcting, diagnosis is important so that surgical intervention and biopsy can be avoided and conservative management instituted.

Focal nodular hyperplasia of the liver--an imaging conundrum

Focal nodular hyperplasia is a common benign tumour of the liver that usually does not require treatment. This tumour can be difficult to distinguish noninvasively from other lesions in young patients that may require intervention, such as hepatic adenoma and fibrolamellar carcinoma. The authors report three cases of histologically proven focal nodular hyperplasia and one case in which the imaging features strongly suggested this tumour. These cases illustrate many of the variable imaging features of focal nodular hyperplasia. The authors review the typical imaging findings for focal nodular hyperplasia, hepatic adenoma and fibrolamellar carcinoma, indicate the areas of overlap that make noninvasive diagnosis impossible and discuss the role of percutaneous biopsy in establishing the definitive diagnosis.

2D and 3D high resolution gradient echo functional imaging of the brain: venous contributions to signal in motor cortex studies

Recent emphasis on high resolution gradient echo studies in functional imaging has led to the conclusion that there are likely three domains of response to the blood circulation in the brain when considering field inhomogeneity effects of the venous blood pre- and during activation. The first is a coherent effect due to large or macroscopic vessels on the order of the size of the voxel (ca 200-500 microns in most studies). These can lead to very large signal changes (up to 100%). The second is at the venule level (ca 50-200 microns) and is associated with smaller parenchymal changes (usually ca 10% or less). The third is at the capillary level and is associated with much smaller signal changes at 1.5 T and even up to 4 T. The actual signal changes depend on field strength and sequence design. In this paper, we present our experience in detecting the first two domains with 2D and 3D gradient echo imaging at 1.5 T. We find that high resolution enables visualization of the larger small veins in motor cortex studies and that, on occasion, it is possible to see the venule effects as well. We suggest a simple model to explain the large signal changes based on susceptibility changes and partial volume effects. Comparisons of the functional imaging data to this model and to MR angiographic studies are also shown as evidence of the venous sources of the susceptibility changes.

Interaction of citrinin and ochratoxin A

The mycotoxins citrinin and ochratoxin A are produced in common by some molds and have been found together in a number of foods and animal feeds. We used in vitro tests to determine if the same effects are produced by these two mycotoxins when they act both independently and together. Renal cortical cubes prepared from kidneys of young adult Hormel-Hanford miniature swine were cultured in the presence or absence of the toxins for 1 h at 37 degrees C. The concentration of the toxins both singly and in combination ranged from 10(-6) to 10(-3) M. The tissues were incubated, removed, rinsed, and reincubated to measure transport of either tetraethylammonium (TEA) or paraminohippurate (PAH) ions and protein synthesis, using 3H-leucine. The transport data were analyzed by a recently developed logistic function test to ascertain whether the effects were additive, synergistic, or antagonistic. The significance of deviation was tested after a potency multiplier was added to the mixture. Data for three of the five experiments measuring TEA transport indicated a synergistic effect; for the other two, the results were not significantly different from additivity. The same was true for PAH transport. For protein synthesis, one experiment showed synergism; for the other, nonadditivity was not significant. None of the measurements showed antagonism between the two toxins. As with several other systems, tests of biochemical effects showed that administration of citrinin and ochratoxin A together did not elicit either consistent or strong synergistic responses.

Spontaneous mnemonic strategies used by older and younger adults to remember proper names

Little attention has been focused on the spontaneous mnemonic strategies that people use to remember proper names. In the experiment reported here, groups of younger (< 25 years old) and older subjects (> or = 55 years old) were shown a series of 12 name-face pairs and instructed to remember them. In a subsequent test, they were shown the same faces and asked to recall the corresponding names. After the recall task, subjects completed a questionnaire about the mnemonic strategies they used. Our analyses revealed not only that the younger subjects recalled more names than did the older subjects, but also that older and younger subjects reported using certain strategies more frequently than other strategies. Moreover, regression analyses indicated that use of certain mnemonic strategies accounted for a significant proportion of recall performance beyond that accounted for by age alone. Older-old subjects (> or = 70 years old) recalled fewer names than did younger-old subjects (> or = 55 and < 70 years old), but they did not differ in the extent to which they used specific mnemonic strategies. Our results suggest that the use of spontaneous mnemonic strategies may play a role in the difference in proper name recall between younger and older adults.

Typography manipulations can affect priming of word stem completion in older and younger adults

The experiments reported here investigated whether changes of typography affected priming of word stem completion performance in older and younger adults. Across all experiments, the typeface in which a word appeared at presentation either did or did not match that of its 3-letter stem at test. In Experiment 1, no significant evidence of a typography effect was found when words were presented with a sentence judgment or letter judgment task. However, subsequent experiments revealed that, in both older and younger adults, only words presented with a syllable judgment task gave rise to the typography effect (Experiments 2-4). Specifically, performance was greater, when the presentation and test typeface matched than when they did not. Experiment 5, which used stem-cued recall, did not reveal a difference between syllable and letter judgment tasks. These findings highlight the complex nature of word stem completion performance.

Typography manipulations can affect priming of word stem completion in older and younger adults

The experiments reported here investigated whether changes of typography affected priming of word stem completion performance in older and younger adults. Across all experiments, the typeface in which a word appeared at presentation either did or did not match that of its 3-letter stem at test. In Experiment 1, no significant evidence of a typography effect was found when words were presented with a sentence judgment or letter judgment task. However, subsequent experiments revealed that, in both older and younger adults, only words presented with a syllable judgment task gave rise to the typography effect (Experiments 2-4). Specifically, performance was greater, when the presentation and test typeface matched than when they did not. Experiment 5, which used stem-cued recall, did not reveal a difference between syllable and letter judgment tasks. These findings highlight the complex nature of word stem completion performance.

Improvement in cognitive functions and psychiatric symptoms in treatment-refractory schizophrenic patients receiving clozapine

Cognitive functions and psychopathology were assessed in 36 treatment-refractory schizophrenic patients before initiation of clozapine, and at 6 weeks and 6 months, thereafter. Before treatment, cognitive impairment was found in each measure of memory, attention, and executive function as compared with 26 normal controls. After both 6 weeks and 6 months of treatment, significant improvement occurred in the Controlled Oral Word Association Test, a measure of retrieval from reference memory. Improvement was also noted at 6 months in the Category Instance Generation Test, another measure of retrieval from reference memory, and in some, but not all, tests of executive function, attention, and recall memory. Clozapine treatment also resulted in significant improvement in Brief Psychiatric Rating Scale (BPRS) Total and Positive symptom scores at both 6-week and 6-month assessment points. There was some evidence for a relationship between improvement in psychopathology and cognitive function. The improvement in cognitive function during clozapine treatment could have consequences for capacity to work and social function.

Identification of vascular structures as a major source of signal contrast in high resolution 2D and 3D functional activation imaging of the motor cortex at 1.5T: preliminary results

We have measured the T2* signal response associated with cortical activation due to finger motion at 1.5 Tesla. Both thin slice 2D and 3D images show signal intensity changes which vary from 2% to 32% depending on volunteer, echo time, slice thickness, and in-plane resolution. The largest signal change occurred for the thinnest slices and highest resolution (2 mm3). This is consistent with reducing partial volume effects and a simple difference in phase between the intravascular signal and surrounding parenchyma. No inflow enhancement was seen on the 2D or 3D scans, confirming the nature of the signal difference for this approach was due to local field inhomogeneity effects. Using 3D imaging, multiple effects can be seen simultaneously. With a 3D MRA method, it was possible to locate the vessel that was the source of the T2* behavior; it was in each case a vein on the surface of the cortical parenchyma.

High-density genetic map of the BRCA1 region of chromosome 17q12-q21

To facilitate the positional cloning of the breast-ovarian cancer gene BRCA1, we constructed a high-density genetic map of the 8.3-cM interval between D17S250 and GIP on chromosome 17q12-q21. Markers were mapped by linkage in the CEPH and in extended kindreds in our breast cancer series. The map comprises 33 ordered polymorphisms, including 12 genes and 21 anonymous markers, yielding an average of one polymorphism every 250 kb. Twenty-five of the markers are PCR-based systems. The order of polymorphic genes and markers is cen-D17S250-D17S518-HER2-THRA1-RARA-D17S80 -KRT10-[D17S800-D17S857]-GAS- D17S856-EDH17B-D17S855-D17S859-D17S858-[++ +PPY-D17S78]-D17S183-EPB3-D17S579- D17S509-[D17S508-D17S190 = D17S810]-D17S791-[D17S181 = D17S806]-D17S797- HOX2B-GP3A-[D17S507 = GIP]-qter. BRCA1 lies in the middle of the interval, between THRA1 and D17S183. Markers from this map can be used to determine whether cancer is linked to BRCA1 in families, to evaluate whether tumors have lost heterozygosity at loci in the region, and to identify probes for characterizing chromosomal rearrangements from patients and from tumors.

A limited, low-dose computed tomography protocol to examine the sacroiliac joints

Limited, low-dose, three-scan computed tomography (CT) was shown to be as accurate as a complete CT series in examining the sacroiliac joints and is suggested as an effective alternative to plain radiography as the primary means to detect sacroiliitis. The advantages include the brevity of the examination, a 2-fold to 4-fold reduction in radiation exposure relative to conventional radiography and a 20-fold to 30-fold reduction relative to a full CT series. The technique was developed from studies of anatomic specimens in which the articular surfaces were covered with a film of barium to show clearly the synovial surfaces and allow the choice of the most appropriate levels of section. From the anteroposterior scout view the following levels were defined: at the first sacral foramen, between the first and second sacral foramina and at the third sacral foramen. In the superior section a quarter of the sacroiliac joint is synovial, whereas in the inferior section the entire joint is synovial. The three representative cuts and the anteroposterior scout view are displayed on a single 14 x 17 in. (36 x 43 cm) film. Comparative images at various current strengths showed that at lower currents than conventionally used no diagnostic information was lost, despite a slight increase in noise. The referring physicians at the authors' institution prefer this protocol to the imaging routine previously used.

Gamma-aminobutyric acidA receptor regulation: chronic treatment with pregnanolone uncouples allosteric interactions between steroid and benzodiazepine recognition sites

Pregnanolone [5 beta-pregnan-3 alpha-ol-20-one (5 beta 3 alpha)] and allopregnanolone [5 alpha-pregnan-3 alpha-ol-20-one (5 alpha 3 alpha)] are neuroactive steroids that are reduced metabolites of progesterone. Both 5 beta 3 alpha and 5 alpha 3 alpha are potent positive modulators of the gamma-aminobutyric acid response that enhance the binding of [3H]flunitrazepam ([3H] FNZ) to the gamma-aminobutyric acid type A receptor. Chronic (48 hr) exposure of brain neurons in culture to 5 beta 3 alpha or 5 alpha 3 alpha abolishes potentiation of [3H]FNZ binding by these steroids. This uncoupling, or loss of allosteric interactions between steroid and benzodiazepine recognition sites, is dose dependent, stereospecific, and reversible. The number and affinity of [3H]FNZ binding sites are unaffected. In contrast, the steroids 5 beta-pregnan-3 beta-ol-20-one, beta-estradiol, testosterone, progesterone, deoxycorticosterone, and dexamethasone, which show little capacity to potentiate [3H]FNZ binding, are also much less effective in inducing uncoupling of steroid and benzodiazepine recognition sites. These results suggest a mechanism whereby neurons could become refractory to long term modulation by neuroactive steroids. The results are discussed in terms of their possible relevance to premenstrual anxiety and enhanced frequency of seizures in certain women.

Depression as a confounding variable in the estimation of habitual sleep time

Self-reported habitual sleep time is an important variable because short and long sleep times are associated with mortality. Speculation with regard to these results usually focuses on physical health, rather than psychological factors. We investigated the role of anxiety and depression in reports of habitual sleep times by examining the relative and absolute discrepancy between individuals' initial estimates of their sleep times and sleep diaries made over a 2-week period. Results indicated that depressed mood was associated not only with a tendency initially to underestimate length of sleep (relative discrepancy), but also to exaggerate reported sleep time regardless of direction (absolute discrepancy). These results imply that studies that examine relationships between reported sleep times and mortality should take mental health factors into account.

Nonlinear statistical models for the joint action of toxins

A general approach using nonlinear regression models is presented for evaluating additivity, synergism, and antagonism of mixtures of toxins for proportions and ratio-scale response measures. This approach provides several advantages over the analysis methods typically used, which involve linear regression with logits or probits. A single model fit is performed, rather than a multistep procedure. Nonadditive alternative models can be easily constructed and tested against the appropriate additive models. The approach avoids the use of data "adjustments" for nonzero background response rates. The analyses are performed in the natural response metric, making interpretation straightforward. Also, the nonlinear regression model can be reparameterized to provide more meaningful primary parameters.