The effect of handedness on mental rotation of hands: a systematic review and meta-analysis.

Body-specific mental rotation is thought to rely upon internal representations of motor actions. Handedness is a source of distinctly different motor experience that shapes the development of such internal representations. Yet, the influence of handedness upon hand mental rotation has never been systematically evaluated. Five databases were searched for studies evaluating hand left/right judgement tasks in adults. Two independent reviewers performed screening, data extraction, and critical appraisal. Eighty-seven datasets were included, with 72 datasets pooled; all had unclear/high risk of bias. Meta-analyses showed that right-handers were faster, but not more accurate, than left-handers at hand mental rotation. A unique effect of handedness was found on performance facilitation for images corresponding to the dominant hand. Meta-analyses showed that right-handers were quicker at identifying images of right hands than left hands-a dominance advantage not evident in left-handers. Differing hand representations (more lateralised hand dominance in right-handers) likely underpin these findings. Given potential differences between hand preference and motor performance, future research exploring their distinct contributions to mental rotation is warranted.

An exploration of patients' understanding of leg ulceration.

OBJECTIVE: This study aimed to identify patients' understanding of leg ulceration by examining their knowledge of the disease process and their expectations of their treatment outcomes. It also aimed to identify their attitudes to any patient information provided to them. METHOD: A total of 101 patients (median age: 75 years, range: 23-91; 54% female) with current leg ulceration of 16 months' median duration (range: 1-480) were asked about their understanding of their condition and treatment and their expectations of patient information provided by health-care professionals. RESULTS: The majority of patients believed they knew the cause of their ulceration (66%), most frequently attributing it to trauma (28%). The most important part of the treatment was felt to be bandaging (27%) and visiting the clinic (12%). Thirty-nine percent did not know what the term 'venous' meant. 'Trauma' was frequently described as a psychological problem, with only 7% associating the word with a knock or wound. Over half of the patients (64%) expressed an interest in acquiring further information, particularly on how they could assist ulcer healing (51%). CONCLUSION: For patient education to be effective, it must be tailored to the patients' vocabulary using simple concepts and straightforward, unambiguous messages.

Note on comparability of MicroCog test forms.

This study investigated the differences between the Standard and Short forms of MicroCog by comparing Domain scores for a clinical sample of 351 substance abusers which gave a significant difference between scores on the Spatial Processing Domain. Implications for research and clinical use are discussed.

Searching genomes for sequences with the potential to form intrastrand triple helices.

The canonical double-helix form of DNA is thought to predominate both in dilute solution and in living cells. Sequence-dependent fluctuations in local DNA shape occur within the double helix. Besides these relatively modest variations in shape, more extreme and remarkable structures have been detected in which some bases become unpaired. Examples include unusual three-stranded structures such as H-DNA. Certain RNA and DNA strands can also fold onto themselves to form intrastrand triplexes. Although they have been extensively studied in vitro, it remains unknown whether nucleic acid triplexes play natural roles in cells. If natural nucleic acid triplexes were identified in cells, much could be learned by examining the formation, stabilization, and function of such structures. With these goals in mind, we adapted a pattern-recognition program to search genetic databases for a type of potential triplex structure whose presence in genomes has not been previously investigated. We term these sequences Potential Intrastrand Triplex (PIT) elements. The formation of an intrastrand triplex requires three consecutive sequence domains with appropriate symmetry along a single nucleic acid strand. It is remarkable that we discovered multiple copies of sequence elements with the potential to form one particular class of intrastrand triplexes in the fully sequenced genomes of several bacteria. We then focused on the characterization of the 25 copies of a particular approximately 37 nt PIT sequence detected in Escherichia coli. Through biochemical studies, we demonstrate that an isolated DNA strand from this family of E. coli PIT elements forms a stable intrastrand triplex at physiological temperature and pH in the presence of physiological concentrations of Mg(2+).

Effect of transportation stress on ovarian function in superovulated Hereford heifers.

A study was conducted to determine the effect of transportation stress on ovarian function in superovulated heifers. Thirty cyclic Hereford heifers of similar age and weight and in good body condition were randomly assigned to control and stress-treated groups. All animals received two daily injections of 5 mg follicle stimulating hormone (FSH) for 4 d beginning on Day 10 to 12 of the estrous cycle. A blood sample was collected at each FSH injection. On the fourth day of injections, heifers were given 25 mg prostaglandin F(2)alpha (PGF(2)alpha) in the morning and a second injection of 15 mg PGF(2)alpha in the afternoon. During superovulation, the stressed heifers were transported to a different location every 12 h whereas control animals remained at the pretrial site. Following 4 d of intermittent transporting and FSH treatment, stress-treated heifers were recombined with control animals. Ovaries were examined 8 d following the onset of standing estrus to determine length, width, thickness, and number of corpora lutea (CL). Peripheral plasma levels of cortisol were higher in the stressed group (P< 0.1). Least squares means for numbers of CL were 20.4 +/- 2.1 and 15.4 +/- 1.7 for control and treated heifers, respectively (P< 0.1). There were no treatment differences (P> 0.1) between length, width, or thickness of ovaries when the number of CL was held constant. These data suggest that stress of the type, intensity, and duration imposed in this study increased plasma levels of cortisol and reduced ovulation rate as determined by CL formation in superovulated heifers.

Unipolar sensing abnormalities: incidence and clinical significance of skeletal muscle interference and undersensing in 228 patients.

Compared to bipolar lead configurations, unipolar pacing systems presumably enhance sensing of cardiac electrical events but are ore susceptible to electrical interference, including skeletal myopotentials. The incidence and clinical significance of oversensing and of undersensing by unipolar R-wave inhibited pacemakers in 228 patients were assessed by 24-hour Holter monitoring and/or by pectoral muscle exercises. Overall, 38% of patients exhibited oversensing and false inhibition due to skeletal myopotentials. Symptoms due to oversensing occurred in 14% of patients and 58% of these required corrective intervention. The presence of silastic coating on the pulse generator had no effect on the sensing of myopotentials. In addition, the incidence of undersensing as assessed by Holter monitoring was 17% despite adequate implantation R wave amplitudes. Thus, oversensing remains a major clinical problem when using unipolar pacemaker systems and their use has not eliminated undersensing.

Limitations of pacemaker system analyzers for the evaluation of implantable pulse generators.

A variety of commercial pacemaker system analyzers have been used to evaluate the electrical performance of pulse generators prior to implant or at the time of reoperation for pacemaker malfunction. We evaluated the ability of seven commercially available pacemaker system analyzers to provide the data required to determine if a given pulse generator was operating according to its manufacturer's specifications. While all pacemaker system analyzers provided accurate data for rate and pulse duration, values displayed for amplitude and sensitivity were inconsistent due to the methods each pacemaker system analyzer employed to measure these parameters. Overall, 22% of representative test sequences yielded data which would have resulted in the inappropriate rejection of the subject pulse generators for implantation. These observations suggest that pacemaker system analyzers are not suitable for evaluating all pulse generators. Moreover, physicians must be aware of these deficiencies in order to avoid the pitfalls of relying exclusively on pacemaker system analyzer data when troubleshooting pacemaker malfunction.

Dual mode sensing by a variable cycle ventricular synchronous pulse generator.

When the Intermedics Cyberlith pulse generator is operating in its R-wave synchronous (VVT) mode, sensed events may trigger stimulus pulses or inhibit the output circuit. This dual mode response to sensed signals is the result of a variable timing cycle which includes an inhibit alert period (IAP) as well as a synchronous alert period (SAP). Sensed events occurring during the IAP result in inhibition of stimulus pulse output and resetting of the timing circuit. Consequently, during a continuous ECG rhythm strip one may observe synchronous and inhibited sensing responses and slowing of the pacing rate below the programmed rate of the pulse generator.