Anterior and posterior association cortex contributions to the somatosensory P300

A P300 (P3)-evoked response is generated in a variety of mammalian species upon detection of significant environmental events. The P3 component has been proposed to index a neural system involved in attention and memory capacity. We investigated the contribution of anterior and posterior association cortex to somatosensory P3 generation. Somatosensory event-related potentials (ERPs) were recorded in controls (n = 10) and patients with unilateral lesions in temporal-parietal junction (n = 8), lateral parietal cortex (n = 8), or dorsolateral frontal cortex (n = 10). Subjects pressed a button to mechanical taps of the fifth finger (targets; p = 0.12), randomly interposed in sequences of taps to the second (standards; p = 0.76) and the third or fourth finger (tactile novels; p = 0.06). Occasional shock stimuli were delivered to the wrist (shock novels; p = 0.06). The scalp-recorded P3 was differentially affected by anterior and posterior association cortex lesions. Subjects with temporal-parietal lesions showed markedly reduced P3s to all types of stimuli at all scalp locations. The reductions were largest at the parietal electrode site over the lesioned hemisphere. Parietal patients had normal P3s for all stimulus types except for contralateral shock novels, which generated reduced P3s. Frontal lesions had reductions of the novelty P3 over frontal sites with minimal changes in the target P3. The data support the existence of multiple intracranial P3 sources. The data further indicate that association cortex in the temporal-parietal junction is critical for generating the scalp-recorded target and novelty P3s, whereas dorsolateral frontal cortex contributes preferentially to novelty P3 generation. The N2 component was reduced by parietal and frontal lesions in patients who had intact target P3s, suggesting that different neural systems underlie N2 and P3 generation.     

Thoracoscopic excision of mediastinal parathyroid adenomas: a report of two cases and review of the literature

Background:Most abnormal parathyroid glands can be removed through a standard cervical incision; even those in the superior mediastinum. Those located in certain areas of the mediastinum, for example posteriorly or in the aortopulmonic window, historically have required excision through a median sternotomy or thoracotomy. Angioablation is a nonsurgical alternative to management of these lesions.Study Design:We present two case reports of mediastinal parathyroid adenomas that were excised thoracoscopically, and review the literature regarding the management of mediastinal parathyroid adenomas.Results:Both patients who underwent precise localization and thoracoscopic excision of their mediastinal parathyroid adenomas had resolution of their hypercalcemia with minimal associated morbidity and shortened recovery periods.Conclusions:We suggest that thoracoscopic excision of mediastinal parathyroid adenomas is the better means of controlling hypercalcemia secondary to parathyroid adenoma in those patients considered for either median sternotomy, thoracotomy or angiographic ablation where the exact location of the lesion can be established preoperatively.     

Minimally Invasive Axillary– Coronary Artery Bypass

Axillary artery-to-coronary artery bypass using reversed saphenous vein provides a simple method of applying the minimally invasive coronary bypass grafting procedure when the internal thoracic artery is not an adequate conduit. Although this may allow extended use of the minimally invasive coronary bypass procedure, the long-term patency of this technique is unknown.     

Wound healing response in surgical patients: recent food intake is more important than nutritional status

We have recently found that an impairment of the wound healing response (WHR) occurs in surgical patients with protein-energy malnutrition before there are any measurable changes in body fat and protein stores. The hypothesis of this study was that the patients' recent food intake is more important in determining the WHR than the patients' overall nutritional status. We have measured the recent food intake (by dietary recall), the WHR (by hydroxyproline accumulation in subcutaneous GORE-TEX implants), the pre-operative weight loss (per cent), and body fat and protein stores (by in vivo neutron activation analysis) in 83 patients awaiting a major elective gastrointestinal resection, and divided them into two groups: adequate recent food intake (n = 59) and inadequate recent food intake (n = 24). There was no significant difference between these two groups for age, sex, diagnosis, surgical procedure, weight loss (per cent), or the amount of body fat and protein stores but there was a significant difference in the WHR (1.81 +/- 0.16 s.e.m. versus 1.04 +/- 0.22 s.e.m. nmol hydroxyproline/mg GORE-TEX, P less than 0.005). These results show that pre-operative food intake has a greater influence over the wound healing response than absolute losses of protein and fat from body stores and they suggest that the maintenance of a normal food intake up until the time of surgery is of importance in preventing an impairment of the wound healing response.     

44Sacral extracorporeal magnetic stimulation is an effective treatment for pelvic floor dyssynergia; Comparative study with biofeedback therapy

Background: Recent development of extracorporeal magnetic stimulation (ECMS) which uses current‐changing magnetic fields allows the induction of electrical stimulation in the desired deep tissue. Recent study showed the sacral nerve stimulation reduces corticoanal excitability that may play a functional role in anal continence mechanisms. Preliminary study shows that ECMS of sacral nerve can modify pelvic floor function and expel rectal balloon in patients with pelvic floor dyssynergia (PFD). Aims: To evaluate the effect of ECMS compared with biofeedback therapy (BF) in patients with PFD. Methods and Materials: Thirty‐eight patients who fulfilled Rome II criteria for PFD by colon transit time and anorectal function tests, were randomly treated with 8 sessions of ECMS (2/weeks; n = 19) at prone position or BF (2/weeks; n = 19) at sitting position. Stimulation parameters were set at 50–80% of maximum intensity, 10 and 50 Hz frequency, 3 s burst length with 3 and 6 s off using arm‐typed stimulator (BioCom‐1000, Mcube Co., Korea). Symptom scores for constipation with/without anorectal function test were repeatedly measured after each treatment. Response was defined as 50% or more decreased symptom score after treatment (partial response: 30–50%, poor: <30%). Results: Fifteen patients (age 49.1 ± 13.4 years, mean ± SD; 4 men) completed 8 session of BF and 14 patients (54.5 ± 17.6 years, 3 men) completed 8 session of ECMS. Four patients of BF group discontinued treatment due to unsatisfactory therapeutic effect (n = 1) and withdrew consent (n = 3) and 5 patients of ECMS group discontinued treatment because of same reasons (n = 1, 4). Total symptom scores were significantly decreased after treatment of 8 session in both treatment groups (13.4 ± 6.6 vs. 4.3 ± 4.0 for BF, p = 0.009; 14.9 ± 5.6 vs. 3.4 ± 4.0 for ECMS, p < 0.001). Bowel movements per week were also significantly increased after treatment in both groups (median 2 vs. 7 for BF, p = 0.035; median 2 vs. 7 for ECMS, p = 0.008). Thirteen out of 15 patients showed response in BF group and 12 out of 14 showed good response in ECMS group. No adverse effects in both groups. Conclusions: ECMS is as effective as BF for the treatment of PFD. Long‐term effect of ECMS for the patients with pelvic floor dyssynergia need to be evaluated in the near future.     

Drug mixture which improves survival of ischemic rabbit epigastric skin flaps

The chief aim of this study was to maximize flap survival by counteracting the pathophysiological changes occurring during ischemia-reperfusion. Rabbit epigastric skin flaps given 21 hours of ischemia were infused intra-arterially with selected drugs at the start of reperfusion. Compared with control infused ischemic flaps, which had a 33% survival rate on day 7 post-ischemia, significant improvement was found with vasodilators nitrendipine (61%) and prostacyclin (65%) and the thrombolytic agent urokinase (65%); marginal improvement with the free radical scavenger desferrioxamine (53%); but no change with streptokinase (44%), heparin (21%), and ATP-MgCl₂ (35%). A drug mixture comprising all of these agents except streptokinase and urokinase produced 87% survival, suggesting an additive effect. Biochemical assays on skin homogenates and blood implicated oxygen free radicals, neutrophil infiltration, and thromboxane in flap failure. These results imply that multiple factors are responsible for ischemic flap failure and that a mixture of drugs needs to be infused to counteract all of the detrimental changes. © 1994 Wiley-Liss, Inc.     

Comparative susceptibility of species A, B and C of Anopheles quadrimaculatus complex to infection with subperiodic Brugia malayi and Brugia pahangi (Nematoda: Filarioidea).

Susceptibilities of natural populations of sibling species A, B and C of the Anopheles quadrimaculatus complex and the colonized strain A to subperiodic Brugia malayi and Brugia pahangi were compared. All 3 sibling species showed varying degrees of susceptibility to both B. pahangi and B. malayi, and they were considerably more susceptible to B. pahangi than to B. malayi. The rate and intensity of infection to B. pahangi were highest for species A (66.2% and 7.4 L3/female, respectively) and lowest for species B (21.3% and 1.7 L3/female). For B. malayi these values were higher for species A (29.7% and 1.84 L3/female) than for species B (13.3% and 0.86 L3/female) and C (12.6% and 0.75 L3/female). The colonized strain A of An. quadrimaculatus was significantly more susceptible to both Brugia species than the natural populations of sibling species A, B and C.     

The fragile X syndrome.

An amplification of a highly unstable DNA element has been identified at the fragile X locus in Xq27.3. This sequence appears to be both the source of the primary mutation causing the fragile X syndrome, apparently having its causative effect through the methylation of the FMR-1 HTF island and the region of cytogenetic fragility. The direct analysis of the genotype of carrier and affected individuals can be used as a direct diagnosis tool which will improve both the accuracy and speed of diagnosis. The identification of hereditary unstable DNA in a disease with such a wide level of non-penetrance and variable phenotype may give clues as to the basis of non-penetrance in other human genetic disorders.     

Epstein-Barr virus latent and replicative gene expression in oral hairy leukoplakia

Oral hairy leukoplakia is an epithelial lesion of the tongue associated with productive infection by Epstein-Barr virus (EBV). However, no data concerning the pattern of EBV latent gene expression have been reported, and it remains unresolved whether true latent infection occurs in basal cell layers of oral hairy leukoplakia. We have studied six cases of oral hairy leukoplakia using monoclonal antibody immunohistology for EBV latent--EB nuclear antigen (EBNA) 1, EBNA 2 and latent membrane protein 1 (LMP 1); immediate-early (BZLF1); and replicative (EA, VCA, MA) proteins, and for the EBV-receptor (CD21 antigen). EBV DNA was demonstrated by nucleic acid in situ hybridization. Mid- to upper-zone keratinocytes contained EBV DNA and co-expressed EBNA 1, EBNA 2 (5 of 6 cases), LMP 1, BZLF1 protein, EA, VCA and MA. No EBV genome or gene expression could be demonstrated in basal or parabasal cells. Spinous keratinocytes were labelled by anti-CD21 antibodies HB5 and B2, but did not express the EBV-receptor as defined by reactivity with OKB7. The co-expression of latent and replicative infection-associated antigens is striking, indicating possible functional roles for latent proteins during the productive cycle. Our results suggest that oral hairy leukoplakia is caused by repeated direct infection of upper epithelial cells with virus from saliva or adjacent replicatively infected cells, rather than by a latent EBV infection of basal epithelial cells with a differentiation-dependent switch to productive infection as previously proposed.