Somatosensory evoked potentials are unchanged by reflex sympathetic dystrophy and by stellate ganglion block.

Median nerve somatosensory evoked potentials (SEPs) were monitored in patients with chronic pain before and after stellate ganglion blockade. A change caused by the syndrome or by the block would suggest that SEPs might be useful in the diagnosis and treatment of chronic pain. We observed 20 subjects. Group I (n = 10) had chronic pain not involving the upper extremity. Group II (n = 8) had reflex sympathetic dystrophy of the arm. All patients underwent unilateral stellate ganglion block using an anterior paratracheal approach. The SEPs were recorded by median nerve stimulation on the blocked (affected) side and unblocked (unaffected) side before and 30 min after the block. Recording sites were ipsilateral brachial plexus, the cervical spinal cord, and the contralateral sensory cortex. There were no between-group differences before or after the block. Paired analysis within each group showed that the SEPs were not different from baseline (unaffected side before block) at any time throughout the study. We conclude that since SEPs are not changed by the reflex sympathetic dystrophy or stellate ganglion block, they would not be useful in the evaluation of pain or in determining the effectiveness of sympathetic block. Both the pain and the block appear to involve alteration of conducting pathways separate from those monitored by median nerve SEPs.     

Inactivation of Exonuclease 1 in mice results in DNA mismatch repair defects,increased cancer susceptibility,and male and female sterility

Exonuclease 1 (Exo1) is a 5'-3' exonuclease that interacts with MutS and MutL homologs and has been implicated in the excision step of DNA mismatch repair. To investigate the role of Exo1 in mammalian mismatch repair and assess its importance for tumorigenesis and meiosis, we generated an Exo1 mutant mouse line. Analysis of Exo1(-/-) cells for mismatch repair activity in vitro showed that Exo1 is required for the repair of base:base and single-base insertion/deletion mismatches in both 5' and 3' nick-directed repair. The repair defect in Exo1(-/-) cells also caused elevated microsatellite instability at a mononucleotide repeat marker and a significant increase in mutation rate at the Hprt locus. Exo1(-/-) animals displayed reduced survival and increased susceptibility to the development of lymphomas. In addition, Exo1(-/-) male and female mice were sterile because of a meiotic defect. Meiosis in Exo1(-/-) animals proceeded through prophase I; however, the chromosomes exhibited dynamic loss of chiasmata during metaphase I, resulting in meiotic failure and apoptosis. Our results show that mammalian Exo1 functions in mutation avoidance and is essential for male and female meiosis.     

Differential effects of two types of environmental novelty on activity and sleep in BALB/cJ and C57BL/6J mice

Change in the sleeping environment can produce significant alterations in sleep. To determine how these alterations may vary with the amount of change and the relative reactivity of the sleeper, we examined the influences of environmental novelty on sleep in two mouse strains that differ in behavioral anxiety. Mice [BALB/cJ (n=7) and C57BL/6J (n=8)] were implanted for recording EEG and activity via telemetry. Following baseline data collection, activity and sleep were examined over 46 h after routine cage change, after placing a simple novel object (PVC Tee) in the home cage, and after handling controls. Mice of both strains showed immediate increases in activity and decreases in rapid eye movement sleep (REM) and non-REM (NREM) after cage change and novel object. Within strain, changes in activity and sleep were greater after cage change than after novel object. Changes in activity and sleep time were significantly correlated in each strain. Compared to C57BL/6J mice, BALB/cJ mice exhibited greater and longer duration initial reductions in sleep time, and greater increases in EEG slow wave activity power after cage change and novel object, but these changes were not followed with subsequent increases in sleep time. In contrast, C57BL/6J mice showed significantly greater subsequent increases in sleep time following the initial reductions induced by both manipulations. The results suggest that initial decreases and subsequent increases in sleep time are related to putative differences in the intensity of environmental novelty (cage change>novel object) and to previously described strain differences in anxiety (BALB/cJ>C57BL/6J).     

Oxytocin increases bias,but not accuracy,in face recognition line-ups

Previous work indicates that intranasal inhalation of oxytocin improves face recognition skills, raising the possibility that it may be used in security settings. However, it is unclear whether oxytocin directly acts upon the core face-processing system itself or indirectly improves face recognition via affective or social salience mechanisms. In a double-blind procedure, 60 participants received either an oxytocin or placebo nasal spray before completing the One-in-Ten task—a standardized test of unfamiliar face recognition containing target-present and target-absent line-ups. Participants in the oxytocin condition outperformed those in the placebo condition on target-present trials, yet were more likely to make false-positive errors on target-absent trials. Signal detection analyses indicated that oxytocin induced a more liberal response bias, rather than increasing accuracy per se. These findings support a social salience account of the effects of oxytocin on face recognition and indicate that oxytocin may impede face recognition in certain scenarios.     

Spouse Confidence in Self-Efficacy for Arthritis Management Predicts Improved Patient Health

Background

In addition to patient self-efficacy, spouse confidence in patient efficacy may also independently predict patient health outcomes. However, the potential influence of spouse confidence has received little research attention.

Purpose

The current study examined the influence of patient and spouse efficacy beliefs for arthritis management on patient health.

Methods

Patient health (i.e., arthritis severity, perceived health, depressive symptoms, lower extremity function), patient self-efficacy, and spouse confidence in patients’ efficacy were assessed in a sample of knee osteoarthritis patients (N?=?152) and their spouses at three time points across an 18-month period. Data were analyzed using structural equation models.

Results

Consistent with predictions, spouse confidence in patient efficacy for arthritis management predicted improvements in patient depressive symptoms, perceived health, and lower extremity function over 6 months and in arthritis severity over 1 year.

Conclusions

Our findings add to a growing literature that highlights the important role of spouse perceptions in patients’ long-term health.     

Age of acquisition effects on spelling in surface dysgraphia

Background: It is not known whether the age of acquisition (AoA) of a word has any significant effect on the spelling performance of normal or impaired speakers. One way to explore this question is to examine the effects of AoA on surface dysgraphia. Aims: We report MK, a patient who suffered herpes simplex viral encephalitis (HSVE) resulting in semantic anomia and surface dysgraphia that we characterise as a tendency to produce a legitimate alternative spelling of a component defined as a LASC error. Methods & Procedures: We describe MK's neuropsychological profile, giving details of impaired naming, spoken and written word comprehension, written picture naming, oral reading, and spelling to dictation, but preserved repetition of whole words. We report experiments designed (1) to test the effect of AoA on spelling by controlling for word frequency as well as other correlated variables using logistic regression and ANOVA, and (2) to test the effects of AoA and sound to spelling predictability on MK's spelling. Outcomes and Results: The results show an effect of AoA but no independent effect of frequency on spelling and an interaction between AoA and predictability, i.e., an effect of AoA on unpredictable word spelling but no effect of AoA on predictable word spelling. Conclusions: We discuss these data with reference to accounts of AoA that locate the effect at the level of mappings between input (phonological) and output (orthographic) representations. We argue that the effect of AoA on spelling is not the result of lexeme activation per se but instead reflects the largely unpredictable mappings between sound and spelling that characterise the majority of English word spellings.     

Hypersensitivity of human testis-tumour cell lines to chemotherapeutic drugs

Metastatic testis tumours, in contrast to most other types of cancer, can be cured by drugs. To investigate which classes of chemotherapeutic drug are differentially toxic to testis-tumour cells, we compared the in vitro dose-response curves of 5 human testis and 5 bladder-cancer cell lines to 12 compounds. The testis cells were hypersensitive to drugs that interact directly with DNA (m-amsa, bleomycin, cisplatin, doxorubicin, methylni- trosourea, mitozolomide, etoposide, mitomycin-C), but little or no difference between the 2 cell types was seen following exposure to drugs whose mechanisms of action do not involve direct interaction with DNA (methotrexate, 5-fluorouracil, colchicine, vinblastine). We conclude that testis tumour cells are either less tolerant of, or have a reduced capacity to repair, DNA damage.