Grey and white matter substrates of action naming.

Despite a persistent interest in verb processing, data on the neural underpinnings of verb retrieval are fragmentary. The present study is the first to analyze the contributions of both grey and white matter damage affecting verb retrieval through action naming in stroke. We used voxel-based lesion-symptom mapping (VLSM) with an action naming task in 40 left-hemisphere stroke patients. Within the grey matter, we revealed the critical involvement of the left precentral and inferior frontal gyri, insula, and parts of basal ganglia. An overlay of white matter tract probability masks on the VLSM lesion map revealed involvement of left-hemisphere long and short association tracts with terminations in the frontal areas; and several projection tracts. The involvement of these structures is interpreted in the light of existing picture naming models, semantic control processes, and the embodiment cognition framework. Our results stress the importance of both cortico-cortical and cortico-subcortical networks of language processing.

Neural mechanisms of two different verbal working memory tasks: A VLSM study.

Currently, a distributed bilateral network of frontal-parietal areas is regarded as the neural substrate of working memory (WM), with the verbal WM network being more left-lateralized. This conclusion is based primarily on functional magnetic resonance imaging (fMRI) data that provides correlational evidence for brain regions involved in a task. However, fMRI cannot differentiate the areas that are fundamentally required for performing a task. These data can only come from brain-injured individuals who fail the task after the loss of specific brain areas. In addition to the lack of complimentary data, is the issue of the variety in the WM tasks used to assess verbal WM. When different tasks are assumed to measure the same behavior, this may mask the contributions of different brain regions. Here, we investigated the neural substrate of WM by using voxel-based lesion symptom mapping (VLSM) in 49 individuals with stroke-induced left hemisphere brain injuries. These participants completed two different verbal WM tasks: complex listening span and a word 2-back task. Behavioral results indicated that the two tasks were only slightly related, while the VLSM analysis revealed different critical regions associated with each task. Specifically, significant detriments in performance on the complex span task were found with lesions in the inferior frontal gyrus, while for the 2-back task, significant deficits were seen after injury to the superior and middle temporal gyri. Thus, the two tasks depend on the structural integrity of different, non-overlapping frontal and temporal brain regions, suggesting distinct neural and cognitive mechanisms triggered by the two tasks: rehearsal and cue-dependent selection in the complex span task, versus updating/auditory recognition in the 2-back task. These findings call into question the common practice of using these two tasks interchangeably in verbal WM research and undermine the legitimacy of aggregating data from studies with different WM tasks. Thus, the present study points out the importance of lesion studies in complementing functional neuroimaging findings and highlights the need to consider task demands in neuroimaging and neuropsychological investigations of WM.

Effects of abdominal location and epididymal or vasal obstructions either individually or in association on ipsilateral and contralateral testes. A histologic and DNA flow cytometric analyses.

OBJECTIVE: An experimental study was conducted to evaluate the damages in ipsilateral and contralateral testes in individual or associated presences of abdominal location and vasal or epididymal obstructions. METHODS: Six groups each consisting of 8 rats were established. The groups included sham operation, ligation of the vas deferens, detachment of the epididymis from testis, abdominal placement of the testis, abdominal placement of the testis with vas deferens ligation, and abdominal placement of the testis with detachment of epididymis from testis. After 30 days, bilateral orchidectomy was performed. Mean seminiferous tubular diameters (MSTD) and mean testicular biopsy scores (MTBS) were obtained for each testis. Relative proportions of haploid, diploid and tetraploid cells were determined by DNA flow cytometry. MSTD, MTBS and the proportions of haploid cells were compared through one-way analysis of variance. RESULTS: While vas deferens ligation has diminished MSTD only in the contralateral testes, abdominal testis and detachment of epididymis have diminished MSTD in both ipsilateral and contralateral testes. MTBS were depressed only in the ipsilateral testes in groups of abdominal testis, vas deferens ligation and detachment of epdidymis. However, ratios of haploid DNA were depressed in both ipsilateral and contralateral testes. Abdominal testis together with vas ligation or detachment of epididymis has further depressed the ratios of haploid DNA in both ipsilateral and contralateral testes. CONCLUSION: Compared to their individual presence, the associated presence of abdominal testis and vasal or epididymal obstructions may augment the damages encountered within the ipsilateral and contralateral testes.

Thymic enlargement in childhood.

Thymic masses constitute one of the least common mediastinal masses in childhood. While producing symptoms of airway compromise, they also raise the suspicion of malignancy when detected. Radiological, operative and pathological findings of patients that have been operated for thymic masses in our institution is presented in this paper. Nine patients were operated in our institution during a 12-year-period between 1985-1997 for thymic masses. Ages of the patients ranged from four months to 13 years. With the exception of one, who was diagnosed with a routine chest x-ray, all the patients had respiratory complaints. All the patients had been evaluated with computed tomography preoperatively. In total, seven sternotomies and four thoracotomies were performed to reach the anterior mediastinum. The distribution of masses was as follows two malignant thymomas, three thymic hyperplasia, one lymphocyte-rich thymoma, one epithelial thymoma, one cystic thymoma and one lymphoblastic lymphoma. Although rare, thymic enlargement may be a cause of intractable respiratory complaints in childhood. Because of the high incidence of primary malignancy of the mediastinal neoplasms in childhood, thymic enlargement requires accurate pathological diagnosis and treatment. Median sternotomy with intensive anesthetical care allows proper tumoral exposure.

Primary ovarian lymphoma in an infant: report of a case.

Primary ovarian malignant lymphomas are rarely encountered in children. We present herein the unusual case of an 11-month-old female infant with primary bilateral non-Hodgkin's lymphoma of the ovaries who was treated by bilateral salpingo-oophorectomy followed by chemotherapy. The clinicopathological features of this rare entity are discussed, focusing special emphasis on the diagnostic and therapeutic strategies.

Response selection in the human anterior cingulate cortex.

The anterior cingulate cortex (ACC) has been proposed as part of the brain's attentional control network, but the exact nature of its involvement in cognitive and motor operations is under debate. Assessing effects of human ACC damage directly addresses the problem of ACC function. We report that executive control processes of a patient with a focal right hemisphere anterior cingulate lesion were not compromised. However, her performance level depended on the response modality used. Under the same task requirements, she was impaired when giving manual responses, but not vocal responses. Thus, we provide neuropsychological evidence for functional specialization within the human ACC.

A neuropsychological theory of positive affect and its influence on cognition.

Positive affect systematically influences performance on many cognitive tasks. A new neuropsychological theory is proposed that accounts for many of these effects by assuming that positive affect is associated with increased brain dopamine levels. The theory predicts or accounts for influences of positive affect on olfaction, the consolidation of long-term (i.e., episodic) memories, working memory, and creative problem solving. For example, the theory assumes that creative problem solving is improved, in part, because increased dopamine release in the anterior cingulate improves cognitive flexibility and facilitates the selection of cognitive perspective.

The evaluation of sympathetic system-related contractile activity of the rat vas deferens after ligation and intra-abdominal placement of the testis.

OBJECTIVE: To evaluate the contractile response of the vas deferens in a model of stress, to determine any changes in sympathetic activity as a result of stress in the ipsilateral testis, which decreases blood flow to the contralateral testis. MATERIALS AND METHODS: The study comprised two groups of six rats each; group 1 underwent a sham operation, and in group 2 the right testis was placed into the abdominal cavity and the vas deferens ligated. After 30 days, the vasa deferentia were resected bilaterally and their isometric contractions recorded. Electrical-field stimulation (EFS) was applied through a pair of platinum electrodes and concentration-response curves constructed for noradrenaline at 37 degrees C and to a solution containing 80 mmol/L K+. RESULTS: The vasa deferentia in both groups showed similar contractile responses to EFS, which were frequency-dependent and maximal at 80 Hz. Noradrenaline-induced contractile activity was lower in amplitude in the vasa deferentia of group 2 than in the contralateral and ipsilateral vasa deferentia of group 1, which were not significantly different from each other. All groups responded similarly to high K+. CONCLUSION: Intra-abdominal placement of the testes with vas deferens ligation decreased the contractile response to noradrenaline in the ipsilateral vas deferens without altering the contractile response to EFS and high K+. This difference could be caused by a reduction in the number of postjunctional alpha-adrenergic receptors or decreased receptor sensitivity. Both possibilities suggest that the vas deferens may initiate sympathetic activity, which may be responsible for contralateral testicular deterioration.

The use of eccentric circummeatal-based flap with combined limited urethral mobilization technique for distal hypospadias repair.

We report a suitable approach to the correction of subcoronal meatus for any variants and report our experience with this method. An eccentric circummeatal-based flap was used to treat 42 patients with hypospadias during a 4-year period. The position of the meatus was coronal in 18 patients (43 percent) and subcoronal and distal penile in 16 (38 percent) and 8 (19 percent) patients, respectively. In addition, 19 patients had marked ventriflexion. The mean length of the urethroplasty was 1.1 cm (ranging from 0.6 to 1.7 cm). In no instance was residual ventral curvature noted nor did the neourethra restrict the phallus during erection. The functional and cosmetic results were excellent, and in many cases the glans penis assumed a nearly normal shape and appearance. No patient required a second procedure to improve cosmesis. This is a convenient procedure for correction of distal hypospadias in which the urethral gap is no longer than 2 to 2.5 cm. The surgical repair does not depend on glanular or meatal variations or even if the patient had a previous operation. It is particularly suitable in cases that have marked fibrous chordee.

Respiratory distress due to esophageal perforation caused by ball point ingestion.

A 15-month-old girl who developed respiratory distress which persisted for three days prior to admission demonstrated pleural effusion on the chest x-ray which was determined to be due to esophageal perforation caused by the ingestion of a ball point. A gastrotomy was performed to extract the ball point. A gastrostomy was performed and a chest tube was inserted. The esophagus was normal radiologically within one month. Foreign body ingestion may cause esophageal perforation in childhood. If it goes unnoticed and a diagnosis is delayed, there is danger of the more hazardous development of mediastinitis. It is important that a child with respiratory distress also be evaluated for esophageal foreign body ingestion.

A neuropsychological theory of multiple systems in category learning.

A neuropsychological theory is proposed that assumes category learning is a competition between separate verbal and implicit (i.e., procedural-learning-based) categorization systems. The theory assumes that the caudate nucleus is an important component of the implicit system and that the anterior cingulate and prefrontal cortices are critical to the verbal system. In addition to making predictions for normal human adults, the theory makes specific predictions for children, elderly people, and patients suffering from Parkinson's disease, Huntington's disease, major depression, amnesia, or lesions of the prefrontal cortex. Two separate formal descriptions of the theory are also provided. One describes trial-by-trial learning, and the other describes global dynamics. The theory is tested on published neuropsychological data and on category learning data with normal adults.

Acute blunt traumatic abdominal hernia.

A rare childhood case of acute blunt traumatic abdominal hernia in which the colon and jejunal loops herniated into a large subcutaneous pocket in front of the sternum is presented. Considerations in diagnosis and management are discussed. Emergency laparotomy is indicated after confirmation of the diagnosis by radiologic modalities. Thorough abdominal exploration is warranted to rule out associated injuries. Reduction of the herniated bowel into the abdomen, debridment of the nonviable tissue, and primary tension-free closure of the defect is the appropriate treatment.

A large inguinal hernia with undescended testes and micropenis in Robinow syndrome.

We present a 1 month-old infant with Robinow syndrome and large inguinal hernia, undescended testes and micropenis mimicking penile agenesis. Genital anomalies are common in Robinow syndrome. The ambiguous genitalia appearance may lead to confusion in gender assignment.

Urinary obstruction caused by factitious urethral stones: an amazing manifestation of Munchausen syndrome by proxy.

The diagnosis of Munchausen syndrome by proxy is frequently difficult to document and often delayed. A unique presentation of a case of Munchausen syndrome by proxy involving insertion of factitious stones in the lower urinary tract is reported.

Solitary intestinal fibromatosis mimicking malabsorption syndromes.

A 17-month-old baby had symptoms of malabsorption and partial intestinal obstruction. These were found to be caused by obliteration of the jejunum by solitary intestinal fibromatosis. Solitary intestinal fibromatosis, which may imitate malabsorptive diseases of the intestine, is a rare cause of intestinal obstruction in the neonatal period and infancy. Diagnostic aids and differential diagnosis of this rare disease are discussed, and previously reported cases are reviewed.

A novel class of anti-DNA antibodies identified in BALB/c mice.

We have characterized four IgG monoclonal antibodies (mAbs) derived from BALB/c mice that bind double-stranded DNA (dsDNA) with high affinity. The hydridomas were selected for expression of a member of the VHS107 family. Three of the four cell lines use the VH11 gene and one uses the VH1 gene. These antibodies exhibit many characteristics of pathogenic anti-DNA antibodies. They are high affinity and not broadly crossreactive. Unlike the anti-DNA antibodies in autoimmune mice, they exhibit no somatic mutation in their VH genes. These results demonstrate that somatic mutation of VHS107 genes is not necessary for generating high affinity dsDNA binding. The fact that such antibodies have not previously been reported suggests that they are rare and that their expression may be downregulated in both nonautoimmune and autoimmune individuals.

Rat insulin-like growth factor II gene. A single gene with two promoters expressing a multitranscript family.

We have characterized the single-copy rat gene encoding the protein precursor of insulin-like growth factor II (pre-pro-rIGF-II) that is located downstream from and in the same transcriptional orientation as the homologous insulin II gene (5'-insulin-IGF-II-3'). This gene consists of at least three coding exons and utilizes two promoters that generate alternate 5' non-coding exons. Multiple transcripts from both promoters appear primarily in fetal or neonatal tissues (in all of the developmental stages and tissues that we have examined), but they are extremely rare or undetectable in adult tissues, with the exception of the brain and the spinal cord. These transcripts, which exhibit characteristic developmental profiles in various tissues, differ both in the presence of one of the alternate 5' non-coding exons and in the length of their fourth exon. The possible occurrence of differential splicing or differential polyadenylation (or both) in this region is discussed.

Organization and characterization of genes essential for symbiotic nitrogen fixation from Bradyrhizobium japonicum I110.

A total of 96 independent Tn5 insertions within a 39-kilobase-pair (kbp) segment of chromosomal DNA containing the three structural genes for nitrogenase (nifH, nifD, and nifK) from Bradyhizobium japonicum I110 were obtained in Escherichia coli and transferred to the wild-type strain by marker exchange. Individual transconjugants containing a Tn5 insertion were inoculated onto Glycine max cv. Wilkin (soybeans) and analyzed for their effect on symbiotic nitrogen fixation. In addition to the three structural genes, genes essential for nitrogen fixation (fix genes) were located in three separate regions: 9 kbp upstream of the nifDK operon; 1.5 kbp downstream of the nifDK operon; 4.5 kbp upstream of nifH. All of the fix::Tn5 insertion strains formed nodules which contained low or undetectable levels of nitrogenase activity. Bacteroids isolated from these nodules had approximately the same levels of the nifDK and nifH transcripts as those detectable from nodules formed by the wild-type strain. Western blot analysis of bacteroid proteins from nodules formed by the fix::Tn5 mutants or the wild-type strain showed the presence of similar levels of the nitrogenase protein subunits. The region upstream of nifH was characterized further by DNA sequence analysis and was shown to contain the nifB gene. The coding sequence of the nifB gene consisted of 1,494 nucleotides and was preceded by putative promoter (5' GTGG-10 base pairs [bp] TTGCA 3') and upstream activator (5' TGT-4 bp-T-5 bp-ACA 3') sequences.

Central and peripheral cholinesterase inhibition: effects on anterior pituitary and sympathomimetic function.

Ten physically healthy inpatients of mixed diagnosis received, in a randomized, counterbalanced double-blind paradigm, physostigmine (22 micrograms/kg) and neostigmine (11 micrograms/kg). Infusions were separated by at least 2 days. The differential effects of physostigmine and neostigmine on plasma concentrations of cortisol, prolactin, growth hormone, ACTH, beta-endorphin/beta-lipotropin-like immunoreactivity, dopamine, norepinephrine, and epinephrine are reported. Administration of physostigmine, unlike that of neostigmine, was associated with statistically significant increases in plasma concentrations of cortisol, prolactin, ACTH, beta-endorphin/beta-lipotropin-like immunoreactivity, and epinephrine, presumably via central mechanisms. In a separate study, 15 subjects, mostly depressed inpatients, were pretreated with methscopolamine (0.75 mg) on one day and scopolamine (0.5 mg) on another day, at least 2 days apart, in a randomized, counterbalanced double blind paradigm and subsequently on each day received physostigmine (22 micrograms/kg). Scopolamine significantly attenuated the physostigmine-associated increase in plasma concentrations of cortisol, growth hormone, prolactin, ACTH, and dopamine compared to methscopolamine, and a close-to-significant attenuation of epinephrine as well. These results provide further evidence that physostigmine's effects on plasma concentrations of pituitary hormones and epinephrine occur via central mechanisms and are muscarinically mediated.