Direct electrical stimulation of the somatosensory cortex in humans using electrocorticography electrodes: a qualitative and quantitative report

OBJECTIVE

Recently, electrocorticography-based brain-computer interfaces have been successfully used to translate cortical activity into control signals for external devices. However, the utility of such devices would be greatly enhanced by somatosensory feedback. Direct stimulation of somatosensory cortex evokes sensory perceptions, and is thus a promising option for closing the loop. Before this can be implemented in humans it is necessary to evaluate how changes in stimulus parameters are perceived and the extent to which they can be discriminated.

APPROACH

Electrical stimulation was delivered to the somatosensory cortex of human subjects implanted with electrocorticography grids. Subjects were asked to discriminate between stimuli of different frequency and amplitude as well as to report the qualitative sensations elicited by the stimulation.

MAIN RESULTS

In this study we show that in humans implanted with electrocorticography grids, variations in the amplitude or frequency of cortical electrical stimulation produce graded variations in percepts. Subjects were able to reliably distinguish between different stimuli.

SIGNIFICANCE

These results indicate that direct cortical stimulation is a feasible option for sensory feedback with brain-computer interface devices.

Status of 25(OH)D levels in pregnancy: A study from the North Eastern part of India

INTRODUCTION

An increased prevalence of vitamin D deficiency has been reported from across the globe including India. Various studies have shown an intrinsic relation between various parameters of maternal and fetal wellbeing with maternal vitamin D status during pregnancy.

AIMS

To look for any association of vitamin D status during pregnancy with the modifiable factors - extent of sun exposure, sunscreen use, vegetarian diet, dietary calcium intake, and multivitamin supplementation.

MATERIALS AND METHODS

A total of 50 pregnant females, aged 20-40 years were studied during the first trimester of pregnancy. Fifty age and body mass index (BMI) matched females were taken as controls. Serum 25(OH)D was measured by radioimmunoassay (Diasorin).

RESULT

Forty-two percent of the cases were found to have vitamin D deficiency and 14% were found to have vitamin D insufficiency, whereas 20% of the controls had vitamin D deficiency and 24% had vitamin D insufficiency (P =0.0375). There was a significant association of 25(OH)D levels with extent of sun exposure, sunscreen use, and vegetarian diet. There was no association of 25(OH)D levels with multivitamin supplementation or dietary calcium intake.

CONCLUSION

Vitamin D deficiency was less in our study group as compared with that reported in other Indian studies. Sun exposure, sunscreen use, and vegetarian diet are important modifiable variables significantly associated with vitamin D status in pregnancy.

Assessing a prognostic model for predicting VTE occurrence in cancer patients

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Background: Venous thromboembolism (VTE) poses a significant health risk to cancer patients and is one of the leading causes of death among this population. The most effective way to prevent VTE and reduce its prominence as a public health burden is by identifying high-risk patients and administering prophylactic measures. In 2008, Khorana et al. developed a model that classified patients by risk based on clinical factors. Methods: We conducted a retrospective study to test this model’s efficacy, on 150 patients with cancer receiving chemotherapy at an outpatient oncology clinic between January 1 and August 1, 2011. We aggregated data and assigned points based on the five factors in the Khorana model: site of cancer with 2 points for very high-risk site and 1 point for high-risk site, 1 point each for leukocyte counts more than 11 x 109/L, platelet counts greater than 350 X 109/L, hemoglobin levels less than 100 g/L and/or the use of erythropoiesis-stimulating agents, and BMI greater than 35 kg/m2 (Khorana et al., Blood 2008). Based on this scoring system, patients with 0 points were grouped into the low-risk category, those with 1-2 points were considered intermediate-risk, and those with 3-4 points were classified as high-risk. Results: As shown in the table, VTE incidence for the low-risk group was 1.9%, intermediate-risk group was 3.9%, and high-risk group was 9.1%. Conclusions: High-risk patients were about 4.5 times more likely to develop a VTE than low risk patients. These results provide valuable insight in determining which patients might benefit from prophylaxis and in motivating the design of prospective clinical trials that assess the VTE predictive model in various ambulatory cancer settings. [Table: see text]

Coexistence of Mandibular Arteriovenous Malformation and Cerebellar Arteriovenous Malformation. An Example of Cerebrofacial Arteriovenous Metameric Syndrome Type III

SUMMARY

We describe a patient with cerebellar and mandibular arteriovenous malformations who initially presented with oral haemorrhage and then subsequently had a cerebellar haemorrhage. This is the second reported case of cerebrofacial arteriovenous metameric syndrome type III (CAMS III) in the literature and we discuss the role of homeobox genes in craniofacial development and angiogenesis.

Reversal of restricted diffusion in cerebral venous thrombosis: case report

We report a patient with extensive cerebral venous thrombosis who showed complete reversal of restricted diffusion on MRI, accompanied by excellent clinical recovery. The implications of these findings in relation to interpretation of diffusion changes in cerebral venous thrombosis are discussed, and differences with arterial stroke are highlighted.

In vitro regeneration of Hypericum patulum Thunb.--a medicinal plant

A protocol was developed for high frequency plant regeneration in H. patulum by shoot-tip culture. H. patulum plants were collected from a wild source growing at high altitude in the eastern Himalayas. Multiple buds were initiated from shoot-tips cultured on Murashige and Skoog's medium supplemented with BAP, kinetin. Addition of thiamin HCI, Ca-pantothenate and biotin enhanced multiple shoot formation. Upon transfer to phytohormone free liquid medium following a brief exposure to auxin, root formation occurred from the micro shoots . Rooted plants were hardened and transferred to soil. Regeneration potentiality was found to be constant throughout the year in long term cultures.

Imaging in epilepsy

Epilepsy is a common problem in the paediatric age group. Imaging plays a vital role in identifying the seizure focus. Cross-sectional imaging modalities like CT and MRI have had a major impact on the management of seizure disorders. MRI, because of its high contrast resolution and multiplanar capability is the ideal imaging modality but its use is restricted due to high cost. Computed tomography is cheaper and is the first, and often, the only modality used, especially in the underprivileged areas of the world. In the tropical countries inflammatory granuloma are a common cause of epilepsy and CT is adequate to detect these lesions. Other causes include congenital abnormalities, neoplastic and vascular causes.

Uterine arteriovenous malformations: the role of intravenous 'dual-phase' CT angiography

The authors describe the use of dual-phase intravenous CT angiography of the pelvis in two female patients, who presented with ongoing excessive vaginal bleeding, to demonstrate large adnexal and uterine arteriovenous malformations (AVMs). Power Doppler was used as the initial modality to diagnose the AVMs. CT angiography, along with 3-D rendering in the form of maximum intensity projections and shaded surface display, were especially useful for anatomical conceptualization to the gynecologist. This greatly helped in the subsequent management in the form of therapeutic embolization in both patients by reducing the time, radiation dose, and contrast required for the procedure. Subsequent surgery, which was required in both patients (due to failed embolization), was also greatly aided by the demonstration of the exact extent of the AVMs on axial CT images. Thus, CT angiography emerged as an impressive non-invasive imaging modality for the complete evaluation and management of the uterine AVMs.

Sonographic diagnosis of a ruptured primary hydatid cyst of the gallbladder

We report an unusual case of a ruptured primary hydatid cyst of the gallbladder. The sonographic appearance-a distended gallbladder containing an intraluminal mass with undulating membranes in the neck and body-led to the diagnosis of this extremely rare condition.

Micropropagation and in vitro flowering of Rauvolfia tetraphylla; a potent source of anti-hypertension drugs

A simple protocol for in vitro mass multiplication of Rauvolfia tetraphylla (Apocynaceae) has been developed. The endophytic microflora was controlled by adopting integrated measures. Multiple shoot development was achieved on MS + Kin (0.1-0.2 mg/l) + BAP (0.4-0.5 mg/l) media. Rooting from in vitro shoots occurred on NAA containing media. In vitro flowering was induced in shoot multiplication media.

CT appearances in abdominal tuberculosis. A pictorial essay

Abdominal tuberculosis continues to be endemic in the developing world and has shown a resurgence in the West. Computed tomography (CT) evaluation is singularly informative as it demonstrates involvement of the bowel, peritoneum, lymph nodes, and solid organs in a single examination. A spectrum of CT findings in an immunocompetent population is presented, ranging from subtle to advanced and common to rare. Genitourinary tuberculosis and tuberculosis in AIDS are excluded as they merit separate discussions.

Catastrophic hypoadrenalism in a case of Sjögren's syndrome

We describe a patient with Sjögren's syndrome who died from undiagnosed adrenocortical failure. A positive test for adrenocortical antibody, performed pre-terminally, suggested the underlying diagnosis, which was subsequently confirmed at post-mortem. This case highlights the rare association of Sjögren's syndrome with occult adrenocortical failure. Perhaps a greater awareness of this association and more frequent serological screening are necessary to prevent a fatal outcome.

Resistance to retinoic acid and altered cytokeratin expression of human papillomavirus type 16-immortalized endocervical cells after tumorigenesis

Human papillomaviruses (HPVs) and cigarette smoking are epidemiologically associated with cervical cancer. We recently found that HEN-16 and HEN-16-2 HPV type 16-immortalized endocervical cells form tumors after treatment with cigarette smoke condensate and derived 2 tumor cell line cultures, HEN-16T and HEN-16-2T, respectively. Here, we examine the molecular pathologic effect of tumorigenesis. HEN-16T and HEN-16-2T exhibit unchanged status and expression of integrated HPV 16 DNA. However, the expression of the cytokeratin CK7 and CK13 endocervical cell markers is more homogeneous in monolayer and organotypic raft cultures after tumorigenesis. For the effect of retinoic acid on monolayers for growth inhibition, HEN-16T were significantly less sensitive than the normal and immortalized non-tumorigenic cells. HEN-16-2T were completely resistant. Moreover, the rafts from both tumorigenic cell line cultures were resistant to retinoic acid and continued to display thick rafts and homogeneous severe dysplasia/carcinoma in situ. In contrast, the non-malignant HEN-16 and HEN-16-2 rafts were thinner, and treatment with retinoic acid blocked the formation of severe dysplasia, reconstructing an epithelium resembling that of the normal endocervix. Our results support the significance of non-viral factors in the mechanism by which cigarette smoking induces tumorigenesis in the late stages of HPV-initiated progression to cervical cancer. Importantly, our data indicate that the sensitivity to retinoic acid of the HPV-containing endocervical cells is lost following tumorigenesis in vitro and possibly in women.

Prostate specific antigen and prostatitis. I. Effect of prostatitis on serum PSA in the human and nonhuman primate

Prostate specific antigen (PSA) has become a mainstay in the diagnosis and management of patients with prostate cancer. We have found, as have others, that it may be elevated in patients with prostatic inflammation. Ten patients had clinical evidence of prostatitis and elevated PSA levels. Six of these had persistently elevated levels after antibiotic treatment. After transrectal ultrasonography and biopsy, two had findings of adenocarcinoma, and the rest had a pathologic diagnosis of acute or chronic prostatitis. We studied this process in an experimental model of prostatitis using a nonhuman primate. We infected six cynomolgus monkeys and followed their PSA levels until resolution of the infection. The PSA peaked between 5 and 7 days after inoculation and gradually returned to baseline in 8 weeks. The dramatically elevated serum PSA levels in bacterial prostatitis can cause confusion in the diagnosis of prostatic carcinoma.

Adenocarcinoma of gallbladder presenting as ureteral obstruction

A fifty-five-year-old man presenting with unilateral renal colic and ureteral obstruction was found to have ureteral metastasis from a primary gallbladder carcinoma. This appears to be the second report of such a case in the English literature.