CBFA2, frequently rearranged in leukemia, is not responsible for a familial leukemia syndrome

We have identified a family with an autosomal dominant platelet disorder with a predisposition for developing myeloid malignancies and have previously demonstrated linkage of this trait to chromosome 21q22.1-22.2. The nearest flanking markers, D21S1265 and D21S167, define the familial platelet disorder (FPD) critical region at a genetic distance of approximately 15.2 centimorgans and physical distance of approximately 6 megabases. This locus is of particular interest as it has previously been implicated in the pathogenesis of acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) through the (8;21), (3;21) and (12;21) chromosomal translocations. In each of these cases, the CBFA2 gene is rearranged. As well, there is a potential association of this locus with the hematologic abnormalities seen in Down syndrome (trisomy 21). To identify the mutant gene in this pedigree, a positional cloning strategy has been undertaken. Several candidate genes map to this locus including: CBFA2, IFNAR1, IFNAR2, CRFB4, GART, SON, KCNE1, SCL5A3 and ATP50. CBFA2, as well as IFNAR1 and CRFB4, were the focus of initial mutational analysis efforts. In this report, we exclude CBFA2 as a candidate by Northern and Southern blotting, RNase protection, single-strand conformational polymorphism (SSCP), direct sequencing and gel-shift analysis. Exons of the IFNAR1 and CRFB4 genes were also analyzed by SSCP and demonstrated no evidence of mutation. SSCP analysis identified a new polymorphism in the second exon of the CRFB4 gene and confirmed a previously described polymorphism in the fourth exon of IFNAR1. Efforts are currently underway to delimit further the FPD critical region and to analyze the other known candidate genes, as well as novel candidate genes, which map to this locus.

Natural occurrence of aflatoxins and Aspergillus flavus (Link) in water

Aflatoxins were detected and Aspergillus flavus was identified from water from a cold water storage tank. This is the first published report of such data from water.

Animal models of memory impairment

Memory impairment in the elderly resembles a mild temporal lobe dysfunction. Alterations in the hippocampal formation are also a probable basis for cognitive deficits in some animal models of ageing. For example, aged rats are impaired in hippocampal-dependent tests of spatial memory. Recent studies have revealed considerable structural integrity in the aged hippocampus, even in aged rats with the most impaired spatial memory. In contrast, atrophy/loss of cholinergic neurons in the basal forebrain and deficiency in cholinergic transduction in hippocampus correlate with the severity of spatial memory impairment in aged rats. This evidence supports the longstanding view that age-related loss of memory has a cholinergic basis. In this context, it is somewhat surprising that the use of a selective cholinergic immunotoxin in young rats to further test this hypothesis has revealed normal spatial memory after removing septo-hippocampal cholinergic neurons. Young rats with immunotoxic lesions, however, have other behavioural impairments in tests of attentional processing. These lines of research have implications for understanding the neurobiological basis of memory deficits in ageing and for selecting an optimal behavioural setting in which to examine therapies aimed at restoring neurobiological function.

A residential summer camp for children with vertically transmitted HIV/AIDS: a six-year experience at the Hole in the Wall Gang Camp

Residential camping sessions for children with vertically transmitted human immunodeficiency virus/acquired immunodeficiency syndrome have been offered at The Hole In The Wall Gang Camp for the past six summers. More than 600 children 6 to 12 years of age have attended. Such sessions are expensive and require extensive planning. Medical and nursing needs have increased greatly over the 6-year period, reflecting advances in treatment and especially an escalation of prescribed medications. We have found it possible for these children to have a fun-filled camping experience and participate in a wide variety of activities.

Open reduction and internal fixation of the distal humerus: functional outcome in the elderly

OBJECTIVE

To examine the functional outcome of a cohort of elderly patients after open reduction and internal plate and screw fixation of distal humerus fractures.

DESIGN

Retrospective review of a consecutive series of patients older than 60 years of age who underwent plate and screw fixation of a distal humerus fracture.

MATERIALS AND METHODS

Eighteen patients, aged 63 to 85 years (average, 71 years), underwent open reduction and internal fixation of a displaced distal humerus fracture using plates and screws. Three were Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF) type A, 2 were type B, and 13 were type C fractures. The patients were reviewed at a minimum follow-up of 1 year after surgery.

MEASUREMENTS AND MAIN RESULTS

All patients had a good or excellent clinical result using a standardized method of evaluation. General health status, as measured by the SF-36 Health Survey, was comparable to the published norms for U.S. male and female populations of similar age.

CONCLUSION

Open reduction and internal fixation of the distal humerus in the elderly can provide good clinical results. Good clinical results, however, do not imply good general health status.

Brain aging: changes in the nature of information coding by the hippocampus

Advanced age in rats is associated with a decline in spatial memory capacities dependent on hippocampal processing. As yet, however, little is known about the nature of age-related alterations in the information encoded by the hippocampus. Young rats and aged rats identified as intact or impaired in spatial learning capacity were trained on a radial arm maze task, and then multiple parameters of the environmental cues were manipulated to characterize the changes in firing patterns of hippocampal neurons corresponding to the presence of particular cues or the spatial relationships among them. The scope of information encoded by the hippocampus was reduced in memory-impaired aged subjects, even though the number of neurons responsive to salient environmental cues was not different from that in young rats. Furthermore, after repeated manipulations of the cues, memory-intact aged rats, like young rats, altered their spatial representations, whereas memory-impaired aged rats showed reduced plasticity of their representation throughout testing. Thus changes in hippocampal memory representation associated with aging and memory loss can be characterized as a rigid encoding of only part of the available information.

Disruption of decrements in conditioned stimulus processing by selective removal of hippocampal cholinergic input

The attention directed to environmental stimuli can be modified by experience. For example, preexposure of a conditioned stimulus (CS) in the absence of reinforcement can retard subsequent conditioning of that stimulus when it is paired directly with an unconditioned stimulus, a phenomenon referred to as latent inhibition. Similarly, consistent pairings of a CS with another event can slow the acquisition of new information about that CS. Such phenomena suggest that reductions in the processing of CSs occur when they are made behaviorally irrelevant or consistent predictors of other events. On the basis of the observation that hippocampal lesions prevented such reductions in CS processing, we hypothesized that damage to basal forebrain cholinergic neurons that project to the hippocampus, using microinjections of the selective immunotoxin 192 IgG-saporin into the medial septum/vertical limb of the diagonal band (MS/VDB), also would disrupt normal reductions in CS processing. Lesions of hippocampal cholinergic input disrupted decreases in CS processing, manifested in both an absence of latent inhibition and a lack of reduced processing of a CS that had been a consistent predictor of another CS. These results indicate that cholinergic neurons in the MS/VDB play a role in the regulation of CS processing. Furthermore, these findings (in conjunction with previous findings) implicate both rostral (hippocampal-projecting) and caudal (cortical-projecting) regions of the basal forebrain cholinergic system in the modulation of attention.

Spatial learning and memory at defined points of the estrous cycle: effects on performance of a hippocampal-dependent task

Learning based on hippocampal-dependent spatial navigation in female rats was assessed at identified points in the estrous cycle corresponding to low (estrus) and high (proestrus) circulating estrogen. With background training in water-maze procedures, rats learned the location of an escape platform in the maze in a single session of 8 training trials. A strong spatial bias for the escape platform was also evident in a probe trial used to assess retention of learning 30 min after the training session. This entire protocol was completed in less than an hour. The performance of the estrus and proestrus rats was indistinguishable on all behavioral measures, irrespective of the stage of estrous cycle during the task. These results indicate that rapid learning and retention for spatial information over a relatively short interval may be preserved despite morphological alterations in hippocampal dendritic spine density in the normally cycling female rat.

The role of an amygdalo-nigrostriatal pathway in associative learning

The present study examined the role of an amygdalo-nigrostriatal pathway in associative learning. An asymmetrical lesion model was used to test whether a circuit from the amygdala central nucleus to the dorsolateral striatum, via the substantia nigra, is critical for mediating conditioned orienting responses. Rats with an asymmetrical lesion, consisting of neurotoxic removal of central nucleus neurons in one hemisphere and depletion of the dopamine innervation of the dorsolateral striatum in the contralateral hemisphere, failed to acquire conditioned orienting responses. In contrast, the asymmetrical lesion had no effect on spontaneous orienting or learning another response directed to the source of the food unconditioned stimulus in the same task. A second experiment tested the effect of reversible inactivation of the dorsolateral striatum contralateral to a neurotoxic central nucleus lesion on acquisition of the conditioned orienting response. Although inactivation did not affect spontaneous orienting, rats failed to acquire the conditioned orienting response during sessions in which inactivation occurred. Immediately after the inactivation procedure was terminated, however, a significant increase in orienting to the conditioned stimulus was evident. These data support the interpretation that the dorsolateral striatum provides a route for the expression of the conditioned orienting response but is not essential for acquisition of this learned behavior.

Hippocampal N-methyl-D-aspartate and kainate binding in response to entorhinal cortex aspiration or 192 IgG-saporin lesions of the basal forebrain

Lesion models in the rat were used to examine the effects of removing innervation of the hippocampal formation on glutamate receptor binding in that system. Bilateral aspiration of the entorhinal cortex was used to remove the cortical innervation of the hippocampal formation and the dentate gyrus. The subcortical input to the hippocampus from cholinergic neurons of the basal forebrain was lesioned by microinjection of the immunotoxin 192 IgG-saporin into the medial septum and vertical limb of diagonal band. After a 30-day postlesion survival, the effects of these lesions on N-methyl-D-aspartate-displaceable [3H]glutamate and [3H]kainate binding in the hippocampus were quantified using in vitro autoradiography. The bilateral entorhinal lesion induced a sprouting response in the dentate gyrus, measured by an increase in the width of [3H]kainate binding. It also induced an increase in the density of [3H]kainate binding in CA3 stratum lucidum and an increase in N-methyl-D-aspartate binding throughout the hippocampus proper and the dentate gyrus. The selective lesion of cholinergic septal input did not have any effect on hippocampal [3H]kainate binding and induced only a moderate decrease in N-methyl-D-aspartate binding that was not statistically reliable. The entorhinal and cholinergic lesions were used as in vivo models of the degeneration of hippocampal input that occurs in normal aging and Alzheimer's disease. The results from the present lesion study suggest that some, but not all, of the effects on hippocampal [3H]kainate and N-methyl-D-aspartate binding induced by the lesions are consistent with the status of binding to these receptors in aging and Alzheimer's disease. Consistent with the effects of aging and Alzheimer's disease is an altered topography of [3H]kainate binding after entorhinal cortex lesion and a modest decline in N-methyl-D-aspartate binding after lesions of the cholinergic septal input to the hippocampus.

Spatial learning and memory at defined points of the estrous cycle: effects on performance of a hippocampal-dependent task

Learning based on hippocampal-dependent spatial navigation in female rats was assessed at identified points in the estrous cycle corresponding to low (estrus) and high (proestrus) circulating estrogen. With background training in water-maze procedures, rats learned the location of an escape platform in the maze in a single session of 8 training trials. A strong spatial bias for the escape platform was also evident in a probe trial used to assess retention of learning 30 min after the training session. This entire protocol was completed in less than an hour. The performance of the estrus and proestrus rats was indistinguishable on all behavioral measures, irrespective of the stage of estrous cycle during the task. These results indicate that rapid learning and retention for spatial information over a relatively short interval may be preserved despite morphological alterations in hippocampal dendritic spine density in the normally cycling female rat.

Acute non-A-E hepatitis in the United States and the role of hepatitis G virus infection. Sentinel Counties Viral Hepatitis Study Team

BACKGROUND

Little is known about the relation of the newly discovered hepatitis G virus (HGV) to the cause and clinical course of acute and chronic viral hepatitis.

METHODS

We selected patients from a surveillance study of acute viral hepatitis in four U.S. counties who had acute disease during 1985 to 1986 or 1991 to 1995. Serum samples were tested for HGV RNA by the polymerase chain reaction.

RESULTS

HGV RNA was detected in 4 of 45 patients with a diagnosis of non-A-E hepatitis (9 percent), 23 of 116 patients with hepatitis C (20 percent), 25 of 100 patients with hepatitis A (25 percent), and 32 of 100 patients with hepatitis B (32 percent) (P<0.05 for the comparison of hepatitis B with hepatitis non-A-E or C). The clinical characteristics of the acute illness were similar for patients with HGV alone and those with hepatitis A, B, or C with or without HGV infection. During a follow-up period of one to nine years, chronic hepatitis did not develop in any of the patients with HGV alone, but 75 percent were persistently positive for HGV RNA, as were 87 percent of those with both hepatitis C and HGV infection. The rates of chronic hepatitis were similar in patients with hepatitis C alone (60 percent) and those with both hepatitis C and HGV infection (61 percent).

CONCLUSIONS

The evidence from this surveillance study does not implicate HGV as an etiologic agent of non-A-E hepatitis. Persistent infection with HGV was common, but it did not lead to chronic disease and did not affect the clinical course in patients with hepatitis A, B, or C.

Predictors of becoming redomiciled among older homeless women

The authors test a model to predict residential outcome among 201 homeless women aged 50 and over. On two-year follow-up, 47% were successfully domiciled. Of 12 variables examined using logistic regression analysis, only 2 variables, perceived support and number of community facilities attended were significant predictors of being domiciled on follow-up. Three additional variables-absence of psychosis, a lifetime history of less than one year of homelessness, and number of entitlements-attained near-significance. Although residential outcome is predicted by a few individual characteristics, what is most striking is the lack of suitable housing options.

Treatment of grade III acromioclavicular separations. Operative versus nonoperative management

Twenty-six patients with Grade III acromioclavicular joint separations were evaluated to determine the outcomes of nonoperative and operative management. Evaluation consisted of a detailed functional questionnaire, physical examination, and comprehensive isokinetic strength assessment. The patients were divided into two groups: operative (n = 16) and nonoperative (n = 10). Operative management consisted of coracoclavicular stabilization with heavy suture material and with nine of the sixteen patients treatment also consisted of coracoacromial ligament transfer and lateral clavicle resection. Nonoperative management consisted of short-term immobilization with early range of motion and rehabilitation. The two groups were similar in all characteristics except mean age: 30.7 years for the operative group and 49.6 years for the nonoperative group. Follow-up evaluation was performed an average of 32.9 months after either injury (nonoperative group) or surgery. Our results indicated that nonoperative management was superior to operative management with respect to time to return to work (0.8 months vs. 2.6 months), time to return to athletics (3.5 months vs. 6.4 months) and time of immobilization (2.7 weeks vs. 6.2 weeks). However, operative management was superior to nonoperative management in the following parameters: time to attain completely pain-free status, the patient's subjective impression of pain, range of motion, functional limitations, cosmesis, and long-term satisfaction. There were no significant differences between the two groups with respect to shoulder range of motion, manual muscle testing, or neurovascular findings. Isokinetic strength testing of the involved shoulder, expressed as a percentage of the uninvolved shoulder, showed no significant differences in peak torque, total work, or total power between the operative and nonoperative groups. However, comparison of the involved to the uninvolved extremity within each group did reveal a trend toward decreased peak torque, work, and power for abduction in the involved extremity regardless of the treatment used. These findings reached statistical significance only for power at the slower testing speed (60 degrees/sec). There was also a significant decrease in power in the involved extremity for external rotation at the faster speed (120 degrees/sec) in the nonoperative group. Finally, the absolute values for peak torque, work, and power were significantly greater for all motions tested in the operative group as compared to the nonoperative group. This may reflect the difference in age between the two groups. Based upon the patients studied, there are benefits to both nonoperative and operative methods of treatment of Grade III acromioclavicular separations. Recovery of strength did not differ between the two groups and therefore should be viewed as a less important factor in patient selection for operative versus nonoperative management. Careful patient selection should remain an important aspect of treatment for this controversial injury.

The use of animal models to study the effects of aging on cognition

This review addresses the importance of animal models for understanding the effects of normal aging on the brain and cognitive functions. First, studies of laboratory animals can help to distinguish between healthy aging and pathological conditions that may contribute to cognitive decline late in life. Second, research on individual differences in aging, a theme of interest in studies of elderly human beings, can be advanced by the experimental control afforded in the use of animal models. The review offers a neuropsychological framework to compare the effects of aging in human beings, monkeys, and rodents. We consider aging in relation to the role of the medial temporal lobe in memory, the information processing functions of the prefrontal cortex in the strategic use of memory, and the regulation of attention by distributed neural circuitry. We also provide an overview of the neurobiological effects of aging that may account for alterations in psychological functions.

Rapid reverse transcription-PCR detection of hepatitis C virus RNA in serum by using the TaqMan fluorogenic detection system

We describe the application of a new fluorogenic probe-based PCR assay (TaqMan; Perkin Elmer Corp./Applied Biosystems, Foster City, Calif.) for the detection of hepatitis C virus RNA in serum and plasma. This assay allows for the direct direction of specific PCR products within minutes of completion of the PCR by monitoring the increase in fluorescence of a dye-labeled oligonucleotide probe. We evaluated this assay by comparing the results obtained by nested PCR with those obtained by TaqMan PCR. Test samples included two separate dilutions series of plasma samples from experimentally infected chimpanzees and a panel of 48 serum specimens from patients with community-acquired hepatitis C virus. The quantity of HCV RNA in each chimpanzee plasma sample was determined by using branched DNA (bDNA) signal amplification assay (Quantiplex HCV RNA assay; Chiron Corp., Emeryville, Calif.). Both PCR assays demonstrated similar levels of detection and could reliably detect 13 bDNA genome equivalents per sample. We found an overall concordance of 88% between results of two PCR assays with the community-acquired panel, which resolved to 100% when discrepant samples were retested by nested PCR. TaqMan compared favorably with nested PCR with key advantages of speed, increased throughput, and decreased opportunity for false-positive results because of elimination of second-round amplification.

In vitro autoradiography of ionotropic glutamate receptors in hippocampus and striatum of aged Long-Evans rats: relationship to spatial learning

Using in vitro autoradiography, we investigated [3H] alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, [3H]kainate and [3H]N-methyl-D-aspartate binding in two forebrain regions, the hippocampus and striatum, of young (four months of age) and aged (24-25 months of age) Long-Evans rats that had previously been tested for spatial learning ability in the Morris water maze. Although there was substantial preservation of binding in the aged rats, reductions in binding were present in the aged rats that were specific to ligand and anatomical region. In the hippocampus of aged rats, [3H] alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate binding in CA1 and [3H]kainate binding in CA3 were reduced. In contrast, N-methyl-D-aspartate binding was not significantly different between age groups. There was evidence of sprouting in the dentate gyrus molecular layer of aged rats, indicated by changes in the topography of [3H]kainate binding. Binding density was analysed with respect to patch/matrix compartmentalization in the striatum. The most striking result was a large decrease in N-methyl-D-aspartate binding in aged rats that was not limited to any dorsal/ventral or patch/matrix area of the striatum. Additionally, [3H]kainate binding in striatal matrix was modestly reduced in aged rats. Of these age effects, only N-methyl-D-aspartate binding in the striatum and [3H]kainate binding in the CA3 region of the hippocampus were correlated with spatial learning, with lower binding in the aged rats associated with better spatial learning ability. Age-related alterations in ionotropic glutamate receptors differ with respect to the receptor subtype and anatomical region examined. The age effects were not necessarily indicative of cognitive decline, as only two age-related binding changes were correlated with spatial learning. Interestingly, in these instances, lower binding in the aged rats was associated with preserved spatial learning, suggesting a compensatory reduction in receptor binding in a subpopulation of aged rats.

Detection of adrenomedullin, a hypotensive peptide, in amniotic fluid and fetal membranes

OBJECTIVE

Our purpose was to determine whether adrenomedullin, a multifunctional regulatory peptide involved in blood flow regulation and growth stimulation and with antimicrobial activity, was a component of amniotic fluid from second-trimester human fetus and to determine the source of this peptide.

STUDY DESIGN

A prospective descriptive study was performed on 134 patients undergoing amniocentesis after genetic counseling, ultrasonography, and informed consent. Adrenomedullin expression was determined by immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction in fetal membranes and with radioimmunoassay in amniotic fluids.

RESULTS

Radioimmunoassay of the 134 amniotic fluid specimens revealed adrenomedullin-like immunoreactivity in all of them, ranging in concentration from 10 to 300 fmol/25 microliters (170 +/- 62 fmol/25 microliters). Immunocytochemical analysis, Western blot analysis, reverse transcriptase-polymerase chain reaction, and in situ reverse transcriptase-polymerase chain reaction further established the expression of adrenomedullin protein and messenger ribonucleic acid in fetal amniotic membranes, suggesting that this organ is the source of amniotic adrenomedullin.

CONCLUSIONS

Our results clearly demonstrate the presence of adrenomedullin in second-trimester human amniotic fluid and adrenomedullin messenger ribonucleic acid and protein in amniotic membranes, suggesting that adrenomedullin is a hormone involved in the maintenance of normal pregnancy. Further studies with these molecular tools are in progress to determine the precise role of this hormone and whether adrenomedullin plays a role in the pathogenesis of various disorders of pregnancy.

Preserved neuron number in the hippocampus of aged rats with spatial learning deficits

Hippocampal neuron loss is widely viewed as a hallmark of normal aging. Moreover, neuronal degeneration is thought to contribute directly to age-related deficits in learning and memory supported by the hippocampus. By taking advantage of improved methods for quantifying neuron number, the present study reports evidence challenging these long-standing concepts. The status of hippocampal-dependent spatial learning was evaluated in young and aged Long-Evans rats using the Morris water maze, and the total number of neurons in the principal cell layers of the dentate gyrus and hippocampus was quantified according to the optical fractionator technique. For each of the hippocampal fields, neuron number was preserved in the aged subjects as a group and in aged individuals with documented learning and memory deficits indicative of hippocampal dysfunction. The findings demonstrate that hippocampal neuronal degeneration is not an inevitable consequence of normal aging and that a loss of principal neurons in the hippocampus fails to account for age-related learning and memory impairment. The observed preservation of neuron number represents an essential foundation for identifying the neurobiological effects of hippocampal aging that account for cognitive decline.