Origin of slow cortical oscillations in deafferented cortical slabs

An in vivo preparation has been developed to study the mechanisms underlying spontaneous sleep oscillations. Dual and triple simultaneous intracellular recordings were made from neurons in small isolated cortical slabs (10 mm x 6 mm) in anesthetized cats. Spontaneously occurring slow sleep oscillations, present in the adjacent intact cortex, were absent in small slabs. However, the isolated slabs displayed brief active periods separated by long periods of silence, up to 60 s in duration. During these silent periods, 60% of neurons showed non-linear amplification of low-amplitude depolarizing activity. Nearly 40% of the cells, twice as many as in intact cortex, were classified as intrinsically bursting. In cortical network models based on Hodgkin-Huxley-like neurons, the summation of simulated spontaneous miniature excitatory postsynaptic potentials was sufficient to activate a persistent sodium current, initiating action potentials in single neurons that then spread through the network. Consistent with this model, enlarging the isolated cortical territory to an isolated gyrus (30 mm x 20 mm) increased the probability of initiating large-scale activity. In these larger territories, both the frequency and regularity of the slow oscillation approached that generated in intact cortex. The frequency of active periods in an analytical model of the cortical network accurately predicted the scaling observed in simulations and from recordings in cortical slabs of increasing size.     

肾上腺皮质癌诊治方法的探讨

目的 探讨肾上腺皮质癌的诊断和治疗方法。方法 回顾１９７８－１９９８年收治的１５例肾上腺皮质癌,其中有内分泌功能８例,无内分泌功能７例,均经手术和病理证实。结果 有内分泌功能性上肾上腺皮质癌具有典型肾上腺皮质功能增强的临床表现,如库兴综合征、原发性醛固酮增多症或性征异常;无内分泌功能性肿瘤为腺外表现;如急性腹痛、高血压等,尿１７－羟、１７－酮和血、尿皮质醇、醛固酮的测定及ＣＴ和Ｂ超检查均有助于诊断     

Postpartum cortical blindness

A 30-years-old third gravida with previous normal pregnancies and an unremarkable prenatal course had an emergency lower segment caesarean section at a periphery hospital for failure of labour to progress. She developed bilateral cortical blindness immediately after recovery from anesthesia due to cerebral angiopathy shown by CT and MR scan as cortical infarct cerebral angiopathy, which is a rare complication of a normal pregnancy.     

Adrenal cortical carcinoma

Adrenal cortical carcinoma is a rare endocrine tumor for which complete surgical resection is the only potentially curative treatment. Accurate preoperative evaluation (biochemical and radiographic) of the patient who presents with an adrenal mass maximizes the opportunity for the patient to undergo a complete, margin-negative resection of the primary tumor, which is the most powerful prognostic variable for long-term survival. The response to chemotherapy or mitotane is modest in patients with advanced disease. Hopefully, an improved understanding of the molecular pathogenesis of this challenging tumor will lead to the development of more effective therapies in the future.     

Basic visual function and cortical thickness patterns in posterior cortical atrophy

Posterior cortical atrophy (PCA) is characterized by a progressive decline in higher-visual object and space processing, but the extent to which these deficits are underpinned by basic visual impairments is unknown. This study aimed to assess basic and higher-order visual deficits in 21 PCA patients. Basic visual skills including form detection and discrimination, color discrimination, motion coherence, and point localization were measured, and associations and dissociations between specific basic visual functions and measures of higher-order object and space perception were identified. All participants showed impairment in at least one aspect of basic visual processing. However, a number of dissociations between basic visual skills indicated a heterogeneous pattern of visual impairment among the PCA patients. Furthermore, basic visual impairments were associated with particular higher-order object and space perception deficits, but not with nonvisual parietal tasks, suggesting the specific involvement of visual networks in PCA. Cortical thickness analysis revealed trends toward lower cortical thickness in occipitotemporal (ventral) and occipitoparietal (dorsal) regions in patients with visuoperceptual and visuospatial deficits, respectively. However, there was also a lot of overlap in their patterns of cortical thinning. These findings suggest that different presentations of PCA represent points in a continuum of phenotypical variation.     

Postpartum renal cortical necrosis

Case report Two young females presented with postpartum acute renal failure. A 24-year-old unsupervised primigravida developed severe lowerabdominal pain and vaginal bleeding at 38 weeks gestation. Shewas     

Adrenal cortical cell transplantation

Purpose

The adrenal cortex is a critical component of the hypothalamic-pituitary-adrenal/gonadal axis that coordinates the stress response and maintains homeostasis. The authors hypothesize that adrenal cortical cells can be transplanted in adrenal insufficiency states to regenerate the adrenal cortex.

Methods

Murine adrenal glands were dissociated into adrenal cortical cells. Cells cultured in a collagen matrix were transplanted under the renal capsule. The implants were retrieved 1, 2, 4, and 8 weeks later. Total RNA was extracted from the retrieved specimens and was analyzed by real-time polymerase chain reaction.

Results

All animals survived the surgical procedure. At implant retrieval, a distinct organoid could be visualized under the renal capsule. The expressions of adrenal-specific markers including Sf1, Dax1, Star, Cyp11a, Cyp11b1, and Cyp21 were detectable in the retrieved specimens up to 8 weeks posttransplantation.

Conclusion

Primary adrenal cortical cells retained their gene expressions after heterotopic transplantation. Ex vivo gene transfer followed by adrenal cortical cell transplantation may lead to curative therapy for patients with adrenal insufficiency.     

Epilepsy and cortical dysplasias

Opinion statement  

Pitfalls in cortical localization by intraoperative recording of cortical somatosensory evoked potentials]

Cortical somatosensory evoked potential (SEP) recordings were made in 11 patients who had lesions located in or near the somatosensory or motor gyri to localize the central sulcus and sensorimotor cortex during neurosurgical operations. Cortical localization was successful in 7 of the 11 patients by recording phase reversal waveforms of N20 and P20 at electrode sites in the hand area on opposite sides of the central sulcus. There were 4 cases in which the cortical localization failed. Locations of craniotomy were far distant from the central sulcus retrospectively in 2 of the 4 patients. Cortical SEPs couldn't be recorded despite probable exposure of the hand area and apparently adequate stimulation and recording conditions in 2 patients who had showed no or low amplitude scalp SEP preoperatively. In one of these 2 patients only low amplitude negative waves were recorded at the cortex which was thought far field potentials originated from subcortical structures. In 2 patients cortical SEP was monitored during the removal of the tumors and was useful to estimate the effects of the operative procedures on the sensorimotor cortex. It is concluded that the localization of cortical functions using cortical SEP is useful for reducing risk associated with intracranial surgery. However, we must be aware that there are some pitfalls in this method.     

Differential effects of glucocorticoids on cortical appendicular and cortical vertebral bone mineral content

Summary The susceptibility to glucocorticoid-induced bone loss may vary in different parts of the skeleton. We studied 62 patients with rheumatoid arthritis, 26 of whom were on low-dose glucocorticoid treatment. Bone mineral content (BMC) in the forearm was measured by single photon absorptiometry at a cortical, diaphyseal, and at a mixed cortical and trabecular, metaphyseal site. Lumbar BMC was measured by dual energy computed tomography in a trabecular and a cortical region of interest. The presence of vertebral deformities was evaluated on lateral spine radiographs. After correction for possibly confounding variables, prednisone therapy significantly influenced BMC at both the trabecular (-22.0%, 95% confidence interval-36.0% to-8.1%) and cortical (-24.8%, 95% confidence interval-39.3% to-10.3%) lumbar site. A significant effect was also seen at the metaphyseal (-15.7%, 95% confidence interval-27.1% to-4.2%), but not the diaphyseal (-3.9%, 95% confidence interval-14.1% to 6.4%) site in the forearm. Correlations between peripheral and vertebral BMC were moderate at best. The diaphyseal to metaphyseal BMC ratio did not identify patients with vertebral osteoporosis. It is concluded that the anterior cortical rim of the vertebral body is more susceptible to the effects of glucocorticoids than the cortical bone in the forearm, and that measurements of trabecular and anterior cortical vertebral BMC are essential in the management of patients with possible glucocorticoid-associated osteoporosis.