Hemoglobin level in elite speed skaters from 2000 up to 2005, and its relationship with competitive results.

We studied the mean hemoglobin (Hb) concentration in elite male and female long track junior and senior speed skaters from 2000 to 2005. In addition, the number of abnormal hematological findings observed over this period of time was investigated. We also studied whether there were differences in Hb concentration between top ranked and lower ranked skaters, and whether a relationship between Hb concentration and competitive results could be observed. The present study shows that the mean Hb level in male and female junior and senior long track speed skaters remained fairly stable and did not change from 2000 through 2005. The number and percentage of abnormal hematological findings were found to vary between 0 and 2 %, and failed to show a clear pattern or trend over the years. There was no difference in mean Hb levels between top ranked and lower ranked skaters, and no meaningful relationship between Hb concentration and ranking could be found.

Structure, metallurgy, and mechanical properties of a porous tantalum foam.

This study evaluated a porous tantalum biomaterial (Hedrocel) designed to function as a scaffold for osseous ingrowth. Samples were characterized for structure, Vickers microhardness, compressive cantilever bending, and tensile properties, as well as compressive and cantilever bending fatigue. The structure consisted of regularly arranged cells having struts with a vitreous carbon core with layers of CVI deposited crystalline tantalum. Microhardness values ranged from 240-393, compressive strength was 60 +/- 18 MPa, tensile strength was 63 +/- 6 MPa, and bending strength was 110 +/- 14 MPa. The compressive fatigue endurance limit was 23 MPa at 5 x 10(6) cycles with samples exhibiting significant plastic deformation. SEM examination showed cracking at strut junctions 45 degrees to the axis of the applied load. The cantilever bending fatigue endurance limit was 35 MPa at 5 x 10(6) cycles, and SEM examination showed failure due to cracking of the struts on the tension side of the sample. While properties were variable due to morphology, results indicate that the material provides structural support while bone ingrowth is occurring. These findings, coupled with the superior biocompatibility of tantalum, makes the material a candidate for a number of clinical applications and warrants further and continued laboratory and clinical investigation.

A high performance low magnetic field internal electrospray ionization-fourier transform ion cyclotron resonance mass spectrometer.

A new in-magnetic field electrospray ionization (ESI) and Fourier transform ion cyclotron resonance mass spectrometer has been constructed and evaluated. This system is characterized by the use of multiple concentric cryopanels to achieve ultrahigh vacuum in the ion cyclotron resonance cell region, a probe-mounted internal ESI source, and a novel in-field shutter. Initial experiments demonstrate high resolution mass measurement capability at a field strength of 1 T. Mass resolution of 700,000 has been obtained for the 3+ charge state of Met-Lys-bradykinin (at m/z 440) generated by electrospray ionization. When electron impact ionization was employed, resolution in excess of 9,200,000 was achieved for nitrogen molecular ions (N 2 (+) ). Isotopic resolution for molecular ions of bovine ubiquitin (MW=8565 µ) also was achieved by using small ion populations.

Spontaneous complete regression of high grade non-Hodgkin's lymphoma. Morphologic, immunohistochemical, and gene amplification analyses.

BACKGROUND: Spontaneous regression of non-Hodgkin's lymphoma, occasionally reported in low grade groups, is a rare phenomenon in high grade groups. Clonal proliferation has not been confirmed in the majority of reported cases. In this woman, age 58 years, who had been diagnosed as having high grade immunoblastic lymphoma after excision of a single cervical lymph node, the remaining bilateral cervical, inguinal, and axillary adenopathy regressed completely without any cytotoxic treatments 22 days after biopsy. At the time of this writing, the patient has been free of disease for 24 months. METHODS: Clonality of the lymphoproliferation in the case was examined by immunohistochemistry and polymerase chain reaction (PCR) amplification using paraffin embedded biopsy material. Possible implications of Epstein-Barr virus in the pathogenesis of this process was examined also by PCR amplification and in situ hybridization. RESULTS: The proliferating lymphoid cells showed restricted expression of immunoglobulin (Ig) light chain and amplification of clonally rearranged V-D-J regions of Ig heavy chain gene. Epstein-Barr virus did not appear to be involved in the process. CONCLUSION: The present study shows that spontaneous complete regression of clonal lymphoproliferation that is morphologically a high grade lymphoma can occur.

Richter's syndrome with different immunoglobulin light chain types. Molecular and cytogenetic features indicate a common clonal origin.

To investigate the issue of clonality in Richter's syndrome, phenotypic, molecular genetic, and cytogenetic studies were performed on tumor tissue from a patient with concurrent chronic lymphocytic leukemia and diffuse large cell lymphoma in a single lymph node specimen. The tumor was biphenotypic for immunoglobulin (Ig) expression with surface Ig lambda-positive chronic lymphocytic leukemia and surface and cytoplasmic Ig kappa-positive diffuse large cell lymphoma. DNA samples prepared from areas of the lymph node rich in chronic lymphocytic leukemia cells and diffuse large cell lymphoma cells were examined in parallel. Identical Ig heavy chain gene rearrangements were detected in the BamHI and EcoRI digests of the two samples, but the patterns of rearrangement were different in the HindIII and PstI digests. Because it is very unlikely that multiple rearranged Ig heavy chain gene fragments of identical size would be found in more than one enzyme digest from two independently derived B-cell clones, it is probable that the two processes originated from a single clone. Modifications after rearrangement probably accounted for the differing band sizes seen in the HindIII and PstI digests. These conclusions are supported by cytogenetic analysis, which revealed two clones with a common primary abnormality (trisomy 12), one of which also exhibited secondary abnormalities. Therefore, Richter's syndrome may represent a composite tumor of common clonal origin, even when differences in light chain expression are identified.

Individual differences in infant visual attention: are short lookers faster processors or feature processors?

Individual differences in the duration of infants' visual fixations are reliable and stable and have been linked to differential cognitive performance; short-looking infants typically perform better than long-looking infants. 4 experiments tested the possibility of whether short lookers' superiority on perceptual-cognitive tasks is attributable to attention to the featural details of visual stimuli, or simply to differences in the speed or efficiency of visual processing. To do this, the performance of long- and short-looking 4-month-olds was examined on separate discrimination tasks that could be solved only by processing either featural or global information. The global task was easier than the featural task, but as the amount of time allotted for infants to solve either type of task was decreased, short lookers' performance was superior to that of long lookers. These results thus lend support to a speed or efficiency of stimulus processing interpretation of infant fixation duration.

Form categorization in 10-month-olds.

In five experiments, 10-month-olds were habituated to exemplars of a form category and tested for categorization in paired-comparison trials involving in-category versus out-of-category stimuli. Across these experiments, color was systematically manipulated during habituation and/or test trials. Infants categorized form when color was either held constant or varied during habituation, but failed to categorize form when exposed to color-constant stimuli during habituation and tested for categorization with novel-color form exemplars. Two subsequent experiments traced this failure to the narrow experience of exposure to color-constant exemplars during habituation. These results suggest that (a) infants' internal representation for a category will not include a stimulus dimension not varied in the exemplars from which the category was derived, but (b) if variation in that dimension is experienced, exemplars constructed of novel instances of that dimension will still be regarded as belonging to the category.

Discrimination learning during the first year: stimulus and positional cues.

In four studies, 3-, 6-, and 9-month-old human infants were tested in a discrimination learning task in which visual fixation to a particular stimulus or lateral position was reinforced with an auditory stimulus. In Experiment 1, all age groups exhibited acquisition, extinction, and reinstatement of fixation to the reinforced target or position. Experiment 2 revealed that 3-month-olds retained the positional discrimination but not the stimulus discrimination after a 5-min delay between acquisition and extinction; older infants retained both types of discriminations. In Experiments 3 and 4 we investigated a possible developmental shift in the dominance of positional versus stimulus cues by training infants on displays in which stimulus and position were confounded and then by dissociating the cues on test trials. Results from both experiments indicated positional cue dominance for young infants and stimulus cue dominance for older infants. The findings are discussed in terms of differences in the attentional demands elicited by proprioceptive versus exteroceptive cues.

Infant visual attention in the paired-comparison paradigm: test-retest and attention-performance relations.

The visual behavior of infants in the paired-comparison paradigm was assessed with multiple discrimination tasks week-to-week at 4 and 7 months and longitudinally from 4 to 7 months. Results indicated that although task-to-task reliability was extremely variable and typically low, most measures of infants' attention averaged across multiple tasks were reliable from 1 week to the next as well as relatively stable over the longer longitudinal period. Across all groups, infants who had shorter fixations (i.e., more fixations per fixed-exposure period) during the familiarization phase showed higher novelty preferences. While infants' shift rate during test phases was a reliable individual characteristic at 7 months, it was not at 4 months; rather, data suggested that the difficulty of the stimulus discrimination may be related to young infants' shift rate.

Neonatal behavioral organization and visual processing at three months.

In 2 studies, the Range of State cluster derived from infants' scores on the Neonatal Behavioral Assessment Scale with Kansas Supplements (NBAS-K) was found to correlate significantly with visual discrimination performance at 3 months of age. Contrary to the expectation that NBAS-K orientation scores would predict visual discrimination at 3 months, it was neonatal behavioral state organization that related to later cognitive functioning in infancy.

The stability of visual habituation during the first year of life.

The short-term reliability and long-term stability of visual habituation and dishabituation in infancy were assessed in a sample of 186 infants from 4 age groups (3-, 4-, 7-, and 9-month-olds) seen for 2 within-age sessions and in a sample of 69 infants seen longitudinally at 3, 4, 7, and 9 months of age. Moderate week-to-week reliability (r's = .30-.50) was observed for duration-based and magnitude of habituation variables at all ages, although better reliability was evident at 4 and 9 months than at 3 and 7 months. In most cases, the reliability of habituation magnitude measures was attributable to the reliability of the peak fixation alone. Data from the longitudinal sample suggested that only the duration of peak fixation was consistently stable across the ages tested, although stability for several measures emerged across the 7-9-month testing. No consistent reliability or stability emerged for the presence or magnitude of dishabituation in either sample.

Memorizing: a test of untrained mildly mentally retarded children's problem-solving.

Forty untrained mildly mentally retarded and 32 untrained nonretarded junior high school students were given eight trails of practice on a self-paced memory problem with lists of letters or words. For each trail a new list was presented, requiring ordered recall of terminal list items followed by ordered recall of initial items. Subgroups of solvers and nonsolvers were identified at each IQ level by a criterion of strict recall accuracy. Direct measures of mnemonic activity showed that over trails, solvers at both IQ levels increasingly fit a theoretically ideal memorization method. At neither IQ level did nonsolvers show similar inventions. On early trials, for both IQ levels, fit to the ideal method was uncorrelated with recall accuracy. On late trials fit and recall were highly correlated at each IQ level and across levels. The results support a problem-solving theory of individual differences in retarded and nonretarded children's memory performances.

The effects of ocusert pilocarpine on anterior chamber depth, visual acuity and intraocular pressure in man.

The duration of intraocular pressure reduction by Ocusert Pilocarpine was found to be 10 days for P20 and 12 days for P40. Ocusert Pilocarpine reduced visual acuity and anterior chamber depth less than the aqueous pilocarpine drops.

The duration of action of pilocarpine Ocusert on intraocular pressure in man.

A study of the duration of intraocular pressure reduction of Ocusert P 20 and P 40 revealed that both agents were active in this regard at the end of a week. The side effects of this new mode of medication were less than with conventional Pilocarpine drops.

Studies of an automatic refraction machine.

A study of the Dioptron automatic refraction machine reveals a good reproducibility of the results obtained by the machine. In a comparison with retinoscopy and subjective refraction, the spherical components were well correlated while the cylindrical power was less well related. The rejection rate of the machine was high and its usefulness in refraction is discussed.