The resilience of the developing reading system: multi-modal evidence of incident and recovery after a pediatric stroke.

Decades of neuroscientific findings have elucidated the highly specialized brain areas involved in reading, especially along the ventral occipitotemporal stream where the critical step of recognizing words occurs. We report on a 14-year-old female with temporary dyslexia after a left ventral occipitotemporal ischemic stroke. Our longitudinal multimodal findings show that the resolution of the reading impairment was associated with heightened activity in the left posterior superior and inferior temporal gyri. Our findings highlight the role of the left inferior temporal gyrus in reading and the importance of perilesional and ipsilateral cortical areas for functional recovery after childhood stroke.

Apparent diffusion coefficient scalars correlate with near-infrared spectroscopy markers of cerebrovascular autoregulation in neonates cooled for perinatal hypoxic-ischemic injury.

BACKGROUND AND PURPOSE: Neurologic morbidity remains high in neonates with perinatal hypoxic-ischemic injury despite therapeutic hypothermia. DTI provides qualitative and quantitative information about the microstructure of the brain, and a near-infrared spectroscopy index can assess cerebrovascular autoregulation. We hypothesized that lower ADC values would correlate with worse autoregulatory function. MATERIALS AND METHODS: Thirty-one neonates with hypoxic-ischemic injury were enrolled. ADC scalars were measured in 27 neonates (age range, 4-15 days) in the anterior and posterior centrum semiovale, basal ganglia, thalamus, posterior limb of the internal capsule, pons, and middle cerebellar peduncle on MRI obtained after completion of therapeutic hypothermia. The blood pressure range of each neonate with the most robust autoregulation was identified by using a near-infrared spectroscopy index. Autoregulatory function was measured by blood pressure deviation below the range with optimal autoregulation. RESULTS: In neonates who had MRI on day of life ≥10, lower ADC scalars in the posterior centrum semiovale (r = -0.87, P = .003, n = 9) and the posterior limb of the internal capsule (r = -0.68, P = .04, n = 9) correlated with blood pressure deviation below the range with optimal autoregulation during hypothermia. Lower ADC scalars in the basal ganglia correlated with worse autoregulation during rewarming (r = -0.71, P = .05, n = 8). CONCLUSIONS: Blood pressure deviation from the optimal autoregulatory range may be an early biomarker of injury in the posterior centrum semiovale, posterior limb of the internal capsule, and basal ganglia. Optimizing blood pressure to support autoregulation may decrease the risk of brain injury in cooled neonates with hypoxic-ischemic injury.

Molecular epidemiology of Cryptosporidium spp. and Giardia spp. in mussels (Mytilus californianus) and California sea lions (Zalophus californianus) from Central California.

Cryptosporidium and Giardia are of public health importance, with recognized transmission through recreational waters. Therefore, both can contaminate marine waters and shellfish, with potential to infect marine mammals in nearshore ecosystems. A 2-year study was conducted to evaluate the presence of Cryptosporidium and Giardia in mussels located at two distinct coastal areas in California, namely, (i) land runoff plume sites and (ii) locations near sea lion haul-out sites, as well as in feces of California sea lions (CSL) (Zalophus californianus) by the use of direct fluorescent antibody (DFA) detection methods and PCR with sequence analysis. In this study, 961 individual mussel hemolymph samples, 54 aliquots of pooled mussel tissue, and 303 CSL fecal samples were screened. Giardia duodenalis assemblages B and D were detected in hemolymph from mussels collected near two land runoff plume sites (Santa Rosa Creek and Carmel River), and assemblages C and D were detected in hemolymph from mussels collected near a sea lion haul-out site (White Rock). These results suggest that mussels are being contaminated by protozoa carried in terrestrial runoff and/or shed in the feces of CSL. Furthermore, low numbers of oocysts and cysts morphologically similar to Cryptosporidium and Giardia, respectively, were detected in CSL fecal samples, suggesting that CSL could be a source and a host of protozoan parasites in coastal environments. The results of this study showed that Cryptosporidium and Giardia spp. from the feces of terrestrial animals and CSL can contaminate mussels and coastal environments.

[Medico-social aspects of cerebro-cranial traumas in the city of Aden, Republic Yemen].

The article is devoted to an important problem that has not only medical but also social significance--clinical and epidemiological aspects of head trauma. These studies were not performed in the Republic of Yemen, but they would allow organization of rationally planned medical care system, improvement of quality, reduced disability and mortality due to traumatic brain injury.

[The state and dynamics of craniocerebral traumatism in the Kamchatka Territory].

Cranio-cerebral traumatism occupies the first place among the causes of lethal outcomes and invalidism of the population and is a serious social-economic problem. This situation requires further improvement of organization of neurotraumatic aid to the population. The work determined the regional features of the problem of cranio-cerebral traumatism in the Kamchatka Territory and proposed scientific reasons for organization of medical aid to patients with cranio-cerebral injuries.

High molecular gas fractions in normal massive star-forming galaxies in the young Universe.

Stars form from cold molecular interstellar gas. As this is relatively rare in the local Universe, galaxies like the Milky Way form only a few new stars per year. Typical massive galaxies in the distant Universe formed stars an order of magnitude more rapidly. Unless star formation was significantly more efficient, this difference suggests that young galaxies were much more molecular-gas rich. Molecular gas observations in the distant Universe have so far largely been restricted to very luminous, rare objects, including mergers and quasars, and accordingly we do not yet have a clear idea about the gas content of more normal (albeit massive) galaxies. Here we report the results of a survey of molecular gas in samples of typical massive-star-forming galaxies at mean redshifts of about 1.2 and 2.3, when the Universe was respectively 40% and 24% of its current age. Our measurements reveal that distant star forming galaxies were indeed gas rich, and that the star formation efficiency is not strongly dependent on cosmic epoch. The average fraction of cold gas relative to total galaxy baryonic mass at z = 2.3 and z = 1.2 is respectively about 44% and 34%, three to ten times higher than in today's massive spiral galaxies. The slow decrease between z approximately 2 and z approximately 1 probably requires a mechanism of semi-continuous replenishment of fresh gas to the young galaxies.

The rapid formation of a large rotating disk galaxy three billion years after the Big Bang.

Observations and theoretical simulations have established a framework for galaxy formation and evolution in the young Universe. Galaxies formed as baryonic gas cooled at the centres of collapsing dark-matter haloes; mergers of haloes and galaxies then led to the hierarchical build-up of galaxy mass. It remains unclear, however, over what timescales galaxies were assembled and when and how bulges and disks--the primary components of present-day galaxies--were formed. It is also puzzling that the most massive galaxies were more abundant and were forming stars more rapidly at early epochs than expected from models. Here we report high-angular-resolution observations of a representative luminous star-forming galaxy when the Universe was only 20% of its current age. A large and massive rotating protodisk is channelling gas towards a growing central stellar bulge hosting an accreting massive black hole. The high surface densities of gas, the high rate of star formation and the moderately young stellar ages suggest rapid assembly, fragmentation and conversion to stars of an initially very gas-rich protodisk, with no obvious evidence for a major merger.

HIV prevention research and global inequality: steps towards improved standards of care.

Intensification of poverty and degradation of health infrastructure over recent decades in countries most affected by HIV/AIDS present formidable challenges to clinical research. This paper addresses the overall standard of health care (SOC) that should be provided to research participants in developing countries, rather than the narrow definition of SOC that has characterised the international debate on standards of health care. It argues that contributing to sustainable improvements in health by progressively ratcheting the standard of care upwards for research participants and their communities is an ethical obligation of those in resource-rich countries who sponsor and implement research in poorer ones.

Totally extraperitoneal repair of obturator hernia.

BACKGROUND: One distinct advantage of the 1aparoscopic inguinal hernia repair is the opportunity for clear visualization of the direct, indirect, femoral, and obturator spaces. The surgeon should routinely inspect all of them. Obturator hernia accounts for as few as 0.073% of all hernias, but the mortality rate when it is acutely incarcerated can be as high as 70%. There is only one previous report of a totally extraperitoneal repair for obturator hernia. Five such procedures are described. METHODS: A retrospective review was undertaken to evaluate one surgeon's experience with the totally extraperitoneal repair of obturator hernia over a 4-year period. Four of five cases were completed, and the remaining case was converted to an open procedure. RESULTS: Three hernias were on the right side, and two on the left. One patient presented with an acutely incarcerated obturator hernia and underwent a small bowel resection for strangulated bowel within the obturator space. The other four hernias were found during totally extraperitoneal repair, and the patients were discharged home several hours later. There was one complication, a midline wound infection in the patient with strangulated bowel. It was treated with dressing changes. There were no other complications, and during a follow-up period of 3 to 48 months, there was no recurrence. CONCLUSIONS: The laparoscopic totally extraperitoneal approach allows inspection and repair of direct, indirect, femoral, and obturator hernias. This study found this procedure to be feasible, safe, and highly effective for the diagnosis and repair of obturator hernias.

Investigating a possible cause of mesh migration during totally extraperitoneal (TEP) repair.

BACKGROUND: In experienced hands, laparoscopic inguinal hernia repair has a low rate of recurrence, but it still can recur, and a number of reasons for this have been identified. In published studies, the majority of such cases seem to result from inadequate dissection leading to missed hernias or suboptimal mesh placement. But even with adequate dissection and proper placement of a sufficiently large mesh, recurrence sometimes happens. A number of investigators have cited mesh migration or dislocation as a possible cause, and this study examined how hip flexion affects the position of newly placed meshes and staples in totally extraperitoneal (TEP) repair of inguinal hernia. METHODS: After completion of the dissection and reduction of discovered hernias, a 15 x 15-cm polypropylene mesh was placed either unilaterally or bilaterally, as indicated. The preperitoneal space then was desufflated. The operating table, in an extended -20 degrees position during surgery, was placed in a 90 degrees position for approximately 15 s. After reinsufflation, the possibility of mesh migration and folding was investigated. Finally, the mesh was stapled, the table again extended and flexed, and the possibility of mesh migration and staple dislodgement investigated once more. RESULTS: The mesh did not migrate or become displaced from any potential hernia area, nor did any of the staples become dislodged. CONCLUSIONS: Concern about mesh migration attributable to patients sitting up immediately after surgery appears to be unfounded, at least according to the findings for the current, small, simulated study group.

Totally extraperitoneal (TEP) hernia repair after an original TEPIs it safe, and is it even possible?

BACKGROUND: There are only scant published reports of totally extraperitoneal (TEP) repair of recurrence after a primary TEP procedure. Furthermore, at least two authors have made the statement that such an operation is virtually impossible. METHODS: We have been performing TEP repair of recurrence after TEP since we 1996, and here we present a retrospective review of our experience with the procedure. We employ a method not varying greatly from the standard TEP done for primary hernia. RESULTS: All cases were started laparoscopically, and only one of 20 had to be converted to open. Of these cases, 12 were for same-side recurrence and eight for a contralateral new hernia. With a follow-up of 28-74 months, there have been no fatalities, no complications, and no re-recurrence. CONCLUSION: We have found that TEP repair of recurrent inguinal hernia after a primary TEP repair is entirely feasible technically as well as entirely safe.

Obstructive symptoms associated with the Lap-Band in the first 24 hours.

BACKGROUND: The Lap-Band is a gastric restrictive procedure for the treatment of morbid obesity. We review the etiology of obstructive complications that present in the first postoperative 24 h. METHODS: Fifty-six Lap-Band procedures were performed by one surgeon between January and September 2002. RESULTS: Six patients presented with obstruction within 24 h of surgery: gastric slippage in three patients, gastric edema in one patient, and esophageal hypomotility in two patients. CONCLUSIONS: Placing the band in an esophagogastric position as per Belachew and Weiner reduced our incidence of gastric slippage to none. Endoscopy with placement of a nasogastric feeding tube can relieve obstruction caused by esophageal hypomotility. Gastric edema with no clinical signs of obstruction will resolve with time. Clinicians must be aware of the unique complications that come with the advent of this new procedure.

Laparoscopic adjustable gastric banding: is there a learning curve?

BACKGROUND: To be certified for laparoscopic placement of adjustable gastric banding, surgeons must have advanced laparoscopic experience. Despite previous exposure to other kinds of laparoscopy, there may a learning curve specific to Lap-Band placement. METHODS: Sixty consecutive patients were prospectively separated into two groups: the first 30 patients operated on (group 1) and the second 30 patients operated on (group 2). RESULTS: Both groups were similar statistically in regard to gender, age, and body mass index. Operative time for group 1 was 79 +/- 31.1 min. There were 11 (37%) complications in 10 patients. Operative time for group 2 was 59 +/- 19.9 min. There were two complications (7%). All operations were completed laparoscopically. Operative time was significantly lower in group 2 ( t-test; p = 004). Complications were also significantly lower (chi-square; p = 0.005). The number of reoperations was also reduced and approached statistical significance (chi-square; p = 0.054). Readmissions, although reduced, were not statistically significant. There were no deaths in either group. CONCLUSIONS: Despite a surgeon's history of advanced laparoscopic experience, there is a definite learning curve associated with the laparoscopically placed adjustable gastric band.

Laparoscopic extraperitoneal approach to acutely incarcerated inguinal hernia.

BACKGROUND: Laparoscopic treatment of acutely incarcerated inguinal hernia is uncommon and still controversial. Those being performed almost all use the transabdominal (TAPP) approach. The authors here present their experience with totally extraperitoneal (TEP) repair of acutely incarcerated hernia. METHODS: A retrospective review was undertaken to evaluate the authors' experience with this procedure over a 4-year period. There were 16 cases, 5 of which were performed using a conventional anterior repair. These 5 cases were excluded from the review. The surgery for all of the remaining 11 acutely incarcerated hernias was started laparoscopically using the TEP approach. Eight of the cases were completed this way, whereas three were converted to the open procedure. In addition to standard TEP repair techniques, a releasing incision is required for acutely incarcerated direct, indirect, or femoral hernias. With a direct hernia, the opening of the defect is enlarged to allow safe dissection of its contents. A releasing incision is made at the anteromedial aspect of the defect to avoid injury to the epigastric or iliac vessels. With an indirect hernia, several additional steps are required. The epigastric vessels may be divided; an additional trocar may be placed laterally below the linea semicircularis to facilitate dissection of the sac and to assist with suturing of the divided sac; and the deep internal ring is divided anteriorly at the 12 o'clock position toward the external ring, facilitating dissection of the indirect sac. With a femoral hernia, a releasing incision is made by carefully incising the insertion of the iliopubic tract into Cooper's ligament at the medial portion of the femoral ring. RESULTS: The mean operative time was 50 min (range, 20-120 min), and the length of hospital stay was 5.4 days (range, 1-29 days). During a follow-up period of 9 to 69 months, there was no recurrence, and only two complications. One of these complications was an infected mesh that occurred in a case involving cecal injury. It was treated with continuous irrigation and salvaged. The other complication was a midline wound infection after a small bowel resection for a strangulated obturator hernia. CONCLUSIONS: Familiarity with the anatomy involved leads to the conclusion that the laparoscopic approach, specifically the TEP procedure, can be used without hesitation even in cases of acutely incarcerated hernia.

Grammatical distinctions in the left frontal cortex.

Selective deficits in producing verbs relative to nouns in speech are well documented in neuropsychology and have been associated with left hemisphere frontal cortical lesions resulting from stroke and other neurological disorders. The basis for these impairments is unresolved: Do they arise because of differences in the way grammatical categories of words are organized in the brain, or because of differences in the neural representation of actions and objects? We used repetitive transcranial magnetic stimulation (rTMS) to suppress the excitability of a portion of left prefrontal cortex and to assess its role in producing nouns and verbs. In one experiment subjects generated real words; in a second, they produced pseudowords as nouns or verbs. In both experiments, response latencies increased for verbs but were unaffected for nouns following rTMS. These results demonstrate that grammatical categories have a neuroanatomical basis and that the left prefrontal cortex is selectively engaged in processing verbs as grammatical objects.

Sometimes a noun is just a noun: comments on Bird, Howard, and Franklin (2000).

Bird, Howard, and Franklin (2000) have proposed a semantic-conceptual explanation of grammatical category-specific deficits that attributes impairments in noun and verb processing to two distinct mechanisms. According to their account, apparent deficits in verb production are not category specific, but rather result from the lower imageability of verbs compared to concrete nouns. Noun deficits are said to result from differences in the distribution of semantic feature types such that damage to sensory features results in disproportionate impairments in naming nouns, especially animate nouns, compared to verbs. However, this hypothesis, which we call the "extended sensory/functional theory" (ESFT), fails on several counts. First, the assumption that representations of living things are more heavily freighted with sensory features than are those of nonliving objects does not have any reliable empirical basis. Second, the ESFT incorrectly predicts associations between deficits in processing sensory features and living things or functional features and nonliving things. Finally, there are numerous cases of patients with grammatical category-specific deficits that do not seem to be consistent with damage at the semantic level. All of this suggests that the ESFT is not a useful model for considering grammatical (or semantic) category-specific deficits.

The use of gated cine phase contrast and MR venography in achondroplasia.

OBJECTS: Foramen magnum and jugular foramen stenosis, well-known problems in achondroplasia, may result in brain stem compression and venous outflow obstruction, respectively. We studied a series of children with achondroplasia using gated cine phase contrast (PC) CSF flow studies to evaluate CSF dynamics across the foramen magnum and MR venography (MRV) to depict obstructed venous drainage. METHODS: Ten patients (9 months to 11 years, mean 2.85 years) were referred for possible brain stem compression. MRI included routine sequences, cine PC with velocity encoding (VENC) = 5 cm/s, and MRV. Six patients, including the asymptomatic patient, had brain stem compression without tonsillar herniation; two had tonsillar herniation; and two had neither brain stem compression nor tonsillar herniation. Abnormal tonsillar movement was seen only with tonsillar herniation. MRV showed steno-occlusive disease of the internal jugular vein (IJV) in nine patients, sigmoid sinus in four, and absent or hypoplastic transverse sinus in seven. Veno-occlusive disease was not progressive. No patient had massive hydrocephalus, although larger ventricles were associated with more profuse venous collateral formation and more severe degrees of IJV stenosis. Three patients have undergone CSF diversion. CONCLUSIONS: MR imaging may be useful in defining the pathophysiology of brain stem compression and hydrocephalus in achondroplasia.

MR venography in children with complex craniosynostosis.

PURPOSE: Chronic venous hypertension due to jugular foramen stenosis has been proposed as an etiology for the hydrocephalus and tonsillar herniation seen in some patients with complex craniosynostosis. We report the use of MR venography (MRV) to evaluate venous outflow obstruction in this clinical setting. MATERIALS AND METHODS: We studied 17 patients, (ages 4 months to 34 years; mean 7.3 years) with complex craniosynostosis; 8 patients with Crouzon's syndrome, 2 with Apert's, 1 with Pfeiffer's and 6 patients without an eponymous classification. MR imaging included routine imaging sequences and axial 2D TOF MRV. Patterns of venous drainage and the presence of hydrocephalus and tonsillar herniation were noted. RESULTS: Jugular vein obstruction was seen in 12/17 patients; in 5/8 patients with Crouzon's, 1/2 with Apert's, the single patient with Pfeiffer's and 5/6 patients with nonsyndromic craniosynostosis. The predominant collateral drainage was via the posterior condylar veins. Nine of 12 (75%) of the patients with abnormal MRV had hydrocephalus; 3/8 patients with Crouzon's, 1/2 patients with Apert's, and 5/6 nonsyndromic patients. Two patients had hydrocephalus with normal MRV. Ten patients had tonsillar herniation, which was associated with shunted hydrocephalus in 7/10 patients, and hydrocephalus seen prior to shunt placement in 3/9. Nine of 10 patients with tonsillar herniation had an abnormal MRV, while 1 patient had a normal MRV. Venous pressures measured in 1 patient showed an 8-mm-Hg differential across the skull base. CONCLUSIONS: The posterior condylar veins appear pivotal in maintaining venous drainage when the jugular bulbs are occluded. Although the association between venous outflow obstruction, hydrocephalus and tonsillar herniation is intriguing, evidence of venous outflow obstruction by MRV may not be indicative of significant intracranial venous hypertension.

Grammatical class in lexical production and morhpological processing: Evidence from a case of fluent aphasia.

We present the case of a fluent aphasic patient who is impaired at producing nouns relative to verbs in picture naming, sentence completion, and sentence generation tasks, but is better at both producing and comprehending concrete nouns than abstract nouns. Moreover, he displays a selective difficulty in producing the plural forms of some nouns and pseudowords presented as nouns, but was able to produce the phonologically identical third-person singular forms of corresponding verb homonyms and of the same pseudowords presented as verbs. This pattern of performance casts doubt on the hypothesis that grammatical class effects are always epiphenomena of more general semantic impairments that affect the naming of actions or of concrete objects, and suggests that these effects may arise instead from damage to syntactic processes pertaining specifically to the grammatical properties of words. We also discuss the implications of such damage for models of morphological processing.