Plasma ghrelin levels after laparoscopic sleeve gastrectomy in obese individuals.

Background & objectives: Ghrelin is an orexigenic gut hormone expressed by the gastric fundus. Laparoscopic sleeve gastrectomy (LSG) procedure involves resection of the gastric fundus leading to a decreased appetite and weight loss. This study was undertaken to determine the levels of plasma ghrelin after sleeve gastrectomy in obese patients. Methods: The study was conducted on 90 morbidly obese patients [body mass index (BMI) >40 kg/m[2]] and severely obese patients (BMI >35/kg/m[2]) who underwent sleeve gastrectomy. The patients were followed up for six months. Weight loss parameters and plasma ghrelin levels were assessed pre- and postoperatively. Results: A significant weight loss and decrease in BMI were observed at three and six months postoperatively. A significant decrease in plasma ghrelin levels over six months of follow up postoperatively was also seen. Interpretation & conclusions: These preliminary findings indicated inhibition of ghrelin production after LSG leading to a decrease in the plasma ghrelin levels within a few days of surgery and sustainable weight loss in obese patients.

Solution Nuclear Magnetic Resonance Studies of Sterol Carrier Protein 2 Like 2 (SCP2L2) Reveal the Insecticide Specific Structural Characteristics of SCP2 Proteins in Aedes aegypti Mosquitoes.

Sterol carrier protein 2 like 2 from Aedes aegypti (AeSCP2L2) plays an important role in lipid transport in mosquitoes for its routine metabolic processes. Repeated unsuccessful attempts to crystallize ligand free SCP2L2 prompted us to undertake nuclear magnetic resonance (NMR) spectroscopy to determine its three-dimensional structure. We report here the three-dimensional structures and dynamics of apo-AeSCP2L2 and its complex with palmitate. The (15)N heteronuclear single-quantum coherence spectrum of apo-AeSCP2L2 displayed multiple peaks for some of the amide resonances, implying the presence of multiple conformations in solution, which are transformed to a single conformation upon formation of the complex with plamitate. The three-dimensional structures of apo-AeSCP2L2 and palmitated AeSCP2L2 reveal an α/ß mixed fold, with five ß-strands and four α-helices, very similar to the other SCP2 protein structures. Unlike the crystal structure of palmitated AeSCP2L2, both solution structures are monomeric. It is further confirmed by the rotational correlation times determined by NMR relaxation times (T1 and T2) of the amide protons. In addition, the palmitated AeSCP2L2 structure contains two palmitate ligands, bound in the binding pocket, unlike the three palmitates bound in the dimeric form of AeSCP2L2 in the crystals. The relaxation experiments revealed that complex formation significantly reduces the dynamics of the protein in solution.

Gastrointestinal endoscopy 30-day-associated bacteremia: Nonoutbreak 5-year review in an inner-city, tertiary-care hospital.

BACKGROUND: Gastrointestinal endoscopic procedures (GIEP's) are an essential part of patient care both diagnostically and therapeutically. Post-GIEP infections may be higher than previously reported and may not have been accurately captured in the past. The aim of this study was to determine the incidence and associated factors of bacteremia associated with GIEP's. METHODS: This is retrospective study of GIEPs performed over a five-year period (2018-2022) at an academic medical center. Electronic health records (EHR) identified GIEPs and positive blood cultures within 30 days of procedure. Statistical analysis was performed using non-parametric testing to compare variables due to the small number of positive blood cultures. RESULTS: EHR identified 18,986 GIEP's and 52 true and unique bacteremia out of 17,093 blood cultures during the five-year study period. The highest rate of positive blood culture of 2.84% (18/ 634) was associated with ERCP and the lowest 0.08% (7/ 9029) was associated with colonoscopy. DISCUSSION: Our study showed a reflection of the endemic rate of bacteremia post GIEP's. Our study cannot differentiate endogenous infection versus contaminated (exogenous) endoscopes. ERCP procedures are disproportionately associated with higher incidence of bacteremia. CONCLUSIONS: Clinical surveillance in non-outbreak settings is essential for estimating GIEP related infections. It should be combined with endoscopic reprocessing audits for appropriate prevention of GIEP associated infections.

A novel approach for subretinal implantation of ultrathin substrates containing stem cell-derived retinal pigment epithelium monolayer.

OBJECTIVE: To evaluate the feasibility of a new technique for the implantation of ultrathin substrates containing stem cell-derived retinal pigment epithelium (RPE) cells into the subretinal space of retina-degenerate Royal College of Surgeon (RCS) rats. METHODS: A platform device was used for the implantation of 4-µm-thick parylene substrates containing a monolayer of human embryonic stem cell-derived RPE (hESC-RPE). Normal Copenhagen rats (n = 6) and RCS rats (n = 5) were used for the study. Spectral-domain optical coherence tomography (SD-OCT) scanning and histological examinations were performed to confirm placement location of the implant. hESC-RPE cells attached to the substrate before and after implantation were evaluated using standard cell counting techniques. RESULTS: SD-OCT scanning and histological examination revealed that the substrates were precisely placed in the rat's subretinal space. The hESC-RPE cell monolayer that covered the surface of the substrate was found to be intact after implantation. Cell counting data showed that less than 2% of cells were lost from the substrate due to the implantation procedure (preimplantation count 2,792 ± 74.09 cells versus postimplantation count 2,741 ± 62.08 cells). Detailed microscopic examination suggested that the cell loss occurred mostly along the edges of the implant. CONCLUSION: With the help of this platform device, it is possible to implant ultrathin substrates containing an RPE monolayer into the rat's subretinal space. This technique can be a useful approach for stem cell-based tissue bioengineering techniques in retinal transplantation research.

Clinical profile and distribution of peripheral retinal changes in myopic population in a hospital-based study in North India.

Purpose: To evaluate the prevalence of different types of peripheral retinal changes in a myopic population in North India and correlate them with axial length. Methods: This cross-sectional, hospital-based survey included 600 eyes of 300 myopic individuals, aged between 10 and 40 years, attending the outdoor ophthalmology clinic of a tertiary eye care hospital in North India were examined from July 2019 to July 2020. They were divided into mild, moderate, high, and severe myopia according to the spherical equivalent of refraction. Axial length was recorded. Peripheral retinal changes were examined by scleral indentation binocular indirect ophthalmoscopy. Standardized findings considered with their fundus location were lattice degeneration, white without pressure and white with pressure, snail-track degenerations, peripheral chorioretinal atrophy, retinal holes, tears, and detachment. The study was approved by the institutional ethics committee, and all participants provided informed consent. Results: Peripheral retinal degenerations were found in almost half (53%) of all myopes included in the study. The most common peripheral retinal degeneration found was lattice degeneration, followed by white without pressure, white with pressure, and chorioretinal atrophy. Most of the peripheral retinal degenerations were seen in the temporal quadrant of the fundus, either superotemporal or inferotemporal. There was a significant positive association between the prevalence of peripheral retinal degeneration with age, increased axial length, and severity of myopia. Conclusion: The results of our study indicate the necessity for careful peripheral fundus examinations of all myopes, irrespective of age and degree of myopia, for early diagnosis and better management of visual-threatening complications like retinal detachment.

Clinical Presentation and Management of Eyes with Globe Perforation during Peribulbar and Retrobulbar Anesthesia: A Retrospective Case Series.

PURPOSE: To evaluate the clinical presentation, management, and outcome of eyes with an inadvertent globe perforation during peribulbar or retrobulbar block. METHODS: This retrospective study evaluated the eyes which had an accidental globe perforation during local ocular anesthesia from 2012 to 2020. The patients were divided into three groups: group 1, Clear media with no rhegmatogenous retinal detachment (RRD); group 2, significant vitreous hemorrhage (VH) precluding the retinal view without RRD; and group 3, RRD with/without VH. RESULTS: Twenty-five patients were included in the study. The mean axial length (AL) was 24.7 ± 2.7 mm (range, 20.9-31.2 mm). The most common presenting feature was VH (n = 14). The treatment included retinal laser barrage (n = 7) and vitrectomy (n = 17). Retinal breaks were identified in all the eyes (total breaks = 37). The mean presenting best-corrected visual acuity in groups 1, 2, and 3 were logarithm of the minimum angle of resolution 0.79 ± 0.73, 1.82 ± 0.78, and 2.13 ± 0.59 respectively. All the treated patients had an attached retina at the last follow-up. The mean final best-corrected visual acuity for each group was logarithm of the minimum angle of resolution 0.59 ± 0.79, 0.48 ± 0.26, and 1.25 ± 0.64, respectively (p = 0.006). The development of RRD was associated with a larger AL (p = 0.015); while the development of significant VH associated with the superior location of the perforation (p = 0.015), late recognition of the perforation (p = 0.004), and multiple perforations (p = 0.015). CONCLUSIONS: Early recognition and intervention in eyes with an inadvertent perforation can lead to a good outcome. Eyes with a longer AL, superior, and multiple perforations are at higher risk of developing complications like RRD and VH. Complications like RRD, macular injury, and vascular occlusion are risk factors for poor prognosis.

Humoral immunity against SARS-CoV-2 variants including omicron in solid organ transplant recipients after three doses of a COVID-19 mRNA vaccine.

Objectives: Solid organ transplant recipients (SOTR) receiving post-transplant immunosuppression show increased COVID-19-related mortality. It is unclear whether an additional dose of COVID-19 vaccines can overcome the reduced immune responsiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. Methods: We analysed humoral immune responses against SARS-CoV-2 and its variants in 53 SOTR receiving SARS-CoV-2 vaccination. Results: Following the initial vaccination series, 60.3% of SOTR showed no measurable neutralisation and only 18.9% demonstrated neutralising activity of > 90%. More intensive immunosuppression, antimetabolites in particular, negatively impacted antiviral immunity. While absolute IgG levels were lower in SOTR than controls, antibody titres against microbial recall antigens were higher. By contrast, SOTR showed reduced vaccine-induced IgG/IgA antibody titres against SARS-CoV-2 and its delta variants and fewer linear B-cell epitopes, indicating reduced B-cell diversity. Importantly, a third vaccine dose led to an increase in anti-SARS-CoV-2 antibody titres and neutralising activity across alpha, beta and delta variants and to the induction of anti-SARS-CoV-2 CD4+ T cells in a subgroup of patients analysed. By contrast, we observed significantly lower antibody titres after the third dose with the omicron variant compared to the ancestral SARS-CoV-2 and the improvement in neutralising activity was much less pronounced than for all the other variants. Conclusion: Only a small subgroup of solid organ transplant recipients is able to generate functional antibodies after an initial vaccine series; however, an additional vaccine dose resulted in dramatically improved antibody responses against all SARS-CoV-2 variants except omicron where antibody responses and neutralising activity remained suboptimal.

Clinical characteristics of morning glory disc anomaly in South India.

PURPOSE: Reports of morning glory disc anomaly (MGDA) in India have mostly been case reports. The aim of this study was to describe the demographic and clinical profile of patients with MGDA in South India. MATERIALS AND METHODS: A retrospective review of the medical records of patients with MGDA seen at a tertiary eye hospital in South India over a period of 8 years was carried out. The patients' demographic and clinical data were extracted from the case files and were entered into Epi Info reporting software version 7.2.3.0 and then analyzed. RESULTS: There were 51 eyes of 44 patients with MGDA comprised 25 (56.8%) males and 19 (43.2%) females. Seven (15.9%) patients had bilateral MGDA. The mean age for females was 5.8 years (standard deviation [SD]: 5.8) and for males, 11.2 years (SD: 12.1). This difference was not statistically significant with a P = 0.07. The most common ocular associations were strabismus, refractive error, and retinal detachment, whereas the most common systemic associations were cleft lip and cleft palate. Fifty-one percent of eyes were blind at presentation. CONCLUSION: Patients with MGDA in India tend to present late with poor visual prognosis. Early diagnosis and prompt treatment of blinding complications are crucial in reducing the risk of irreversible visual loss. Associated systemic abnormalities highlight the importance of a multidisciplinary approach in the management of patients with this condition.

Splenic infarction in alcoholic hepatitis.

Splenic infarctions have been reported in cirrhotic patients with comorbidities (e.g., primary biliary cirrhosis), but there is little to no mention of spontaneous splenic infarction in alcoholic hepatitis. This condition is notable, as splenic function has been shown to decrease in alcoholic liver disease, but the exact pathophysiology has been unclear. We describe a relatively young cirrhotic woman who developed splenic infarctions in the setting of alcoholic hepatitis.

Comparison of platelet-rich plasma and inverted internal limiting membrane flap for the management of large macular holes: A pilot study.

Purpose: To compare the safety and efficacy of 25-gauge pars plana vitrectomy (PPV) with either platelet-rich plasma (PRP) or inverted internal limiting membrane (ILM) flap for the treatment of large macular hole. Methods: Pseudophakic patients with idiopathic macular holes with a minimum diameter (MD) of 600-1500 µm were randomized into two groups (30 patients each): 25-gauge PPV with either inverted ILM flap (group A) or PRP (group B). Results: Mean MD in groups A and B were 803.33 ± 120.65 µm and 784.73 ± 120.10 µm, respectively (P = 0.552). Mean base diameter in groups A and B was 1395.17 ± 240.57 µm and 1486.90 ± 281.61 µm, respectively (P = 0.180). The median presenting best-corrected visual acuity (BCVA) was logMAR 0.78 (range 0.78-1.00) and logMAR 0.78 (Range 0.60-1.00) in groups A and B, respectively (P = 0.103). Anatomical closure was achieved in 90% (n = 27/30) and 93.3% (n = 28/30) eyes in groups A and B, respectively (P = 0.158). Type 1 closure was achieved in 76.7% (n = 23/30) and 83.3% (n = 25/30) eyes in groups A and B, respectively. Median BCVA at postoperative 3-month in groups A and B was logMAR 0.60 (range 0.48-0.60) and logMAR 0.60 (range 0.48-0.78), respectively (P = 0.312). The average visual improvement was 2.0 and 2.5 early treatment diabetic retinopathy study (ETDRS) lines in groups A and B, respectively (P = 0.339). None of the patients developed postoperative exaggerated inflammatory reactions. Conclusion: Using platelets for the treatment of large macular holes is as safe and effective as an inverted ILM flap.

Factors Determining Diabetic Remission after Sleeve Gastrectomy: A Prospective Study.

BACKGROUND: An exponential rise in the prevalence of obesity and the associated type 2 diabetes mellitus (T2DM) has led to an explosion in the field of bariatric surgery worldwide. It has been proposed that laparoscopic sleeve gastrectomy (LSG) not only results in excess weight loss (EWL) but also leads to excellent glycemic control. AIMS: However, not every patient benefits from the bariatric surgery. Furthermore, bariatric surgery is currently indicated based on body mass index (BMI), but BMI solely does not predict diabetes remission after the surgery. We aimed to study the outcome of LSG on the diabetic status and the factors predicting the disease remission. SUBJECTS AND METHODS: This prospective study was conducted on 104 obese patients having T2DM who underwent LSG. Following surgery, the clinical outcome on weight loss, BMI, and glycemic control was studied for 6 months. Various positive and negative predictors of diabetic remission after the surgery were also determined. Student's t-test and Chi-square tests were applied. RESULTS: LSG resulted in significant weight loss (P < 0.05); the percentage of EWL was 60.75 ± 6.30 at 6 months. Furthermore, surgery resulted in 78.9% remission of diabetes with fasting blood glucose and glycated hemoglobin values at 6 months being 121.13 ± 15.25 mg/dl and 6.19% ± 0.31%, respectively. Younger and heavier patients, those with lesser disease severity and shorter duration had better chances of disease remission. Gender had no correlation with disease remission. CONCLUSION: LSG is a successful treatment option for T2DM and is more beneficial if offered, not as a last option, but to younger, obese patients with mild disease severity and shorter disease duration after the failure of medical treatment.

Dynamic current density of the disk electrode double-layer.

With applied potential, the current distribution at the surface of a disk electrode is spatially nonuniform and time dependent. This distribution is important to control in applications that desire a uniform current density profile or minimal corrosion. We examine the current density profile of a capacitive disk electrode subjected to a voltage-step using finite element analysis software to solve the system of partial differential equations. In detailed analyses we show quantitatively that the current density shifts from peripheral enhancement to near-uniformity following 1/2 of the lumped element time constant. As charging continues, the current density is slightly enhanced in the central region. We present curves for the evolution of local "time constants" as time progresses and calculate their effective values. The model is intended to be the basis of future work to control the corrosion profile of biologically implantable electrodes of arbitrary shape. Data suggest a means to control corrosion by retarding the edges of a stimulus pulse. Additionally, smaller electrodes may be more effective in fully utilizing surface area for charge transfer due to their shorter time constants.

An in vitro model of a retinal prosthesis.

Epiretinal prostheses are being developed to bypass a degenerated photoreceptor layer and excite surviving ganglion and inner retinal cells. We used custom microfabricated multielectrode arrays with 200-microm-diameter stimulating electrodes and 10-microm-diameter recording electrodes to stimulate and record neural responses in isolated tiger salamander retina. Pharmacological agents were used to isolate direct excitation of ganglion cells from excitation of other inner retinal cells. Strength-duration data suggest that, if amplitude will be used for the coding of brightness or gray level in retinal prostheses, shorter pulses (200 micros) will allow for a smaller region in the area of the electrode to be excited over a larger dynamic range compared with longer pulses (1 ms). Both electrophysiological results and electrostatic finite-element modeling show that electrode-electrode interactions can lead to increased thresholds for sites half way between simultaneously stimulated electrodes (29.4 +/- 6.6 nC) compared with monopolar stimulation (13.3 +/- 1.7 nC, p < 0.02). Presynaptic stimulation of the same ganglion cell with both 200- and 10-microm-diameter electrodes yielded threshold charge densities of 12 +/- 6 and 7.66 +/- 1.30 nC/cm2, respectively, while the required charge was 12.5 +/- 6.2 and 19 +/- 3.3 nC.

The dependence of spectral impedance on disc microelectrode radius.

As microelectrodes gain widespread use for electrochemical sensing, biopotential recording, and neural stimulation, it becomes important to understand the dependence of electrochemical impedance on microelectrode size. It has been shown mathematically that a disc electrode, coplanar in an insulating substrate and exposed to a conducting media, exhibits an inhomogeneous current distribution when a potential step is applied. This distribution is known as the primary distribution, and its derivation also yielded an analytic solution for electrical resistance of the conducting media (R(s)), between the disc surface and a distant ground, which is inversely proportional to disk radius [R(s) = 1/(4kappar), where kappa is media conductivity and r is disk radius]. The dependence of spectral impedance on microelectrode radius, however, has not been explored. We verify the analytical solution for resistance using high-frequency (100 kHz) electrochemical impedance data from microelectrodes of varying radius (11-325 microm). For all disc radii, as we approach a lower frequency (--> 10 Hz), we observe a transition from radial to area dependence (e.g., 1/r --> 1/r2). We hypothesize that this transition is driven by the fact that the derivation of the primary distribution ignores concentration gradients, but that these gradients cannot be ignored at lower frequencies.

Role of Hunger Hormone "Ghrelin" in Long-Term Weight Loss Following Laparoscopic Sleeve Gastrectomy.

INTRODUCTION: Laparoscopic sleeve gastrectomy (LSG) has become a popular weight loss technique in morbidly obese patients. The aim of our study was to evaluate the changes in plasma ghrelin levels in relation to weight loss following LSG and to study the efficacy of LSG in terms of long-term glycemic control and resolution of diabetes. METHODOLOGY: The study was conducted on 70 morbidly obese patients (body mass index [BMI] >40 kg/m2) or severely obese patients (BMI >35 kg/m2) with comorbidities who underwent LSG in Dayanand Medical College and Hospital, Ludhiana, India. Ghrelin levels were measured preoperatively and postoperatively at 1 week, 3 months, and 6 months along with measurements of various weight loss parameters and glycosylated hemoglobin. RESULTS: A significant decrease in plasma ghrelin levels was observed in relation to the mean weight and percentage excess weight loss at 3 months postoperatively. However, at 6 months, fall in ghrelin reached a plateau phase while weight loss was still sustained and significant. There was a significant fall in glycosylated hemoglobin levels with patients achieving good control/resolution of diabetes Type II. CONCLUSION: LSG is an effective weight loss surgery and brings about excellent weight loss in morbidly obese individuals in addition to achievement of good glycemic control in diabetic individuals. Serum levels of ghrelin fall significantly after sleeve gastrectomy. However, long term implications of ghrelin induced weight loss cannot be elucidated.

Risk factors for retinopathy of prematurity in a district in South India: A prospective cohort study.

PURPOSE: The purpose of this study was to determine the incidence, severity, and associated risk factors of retinopathy of prematurity (ROP) in a district in South India. METHODS: This was a prospective, observational, cohort study involving babies at risk of ROP conducted in five Neonatal Intensive Care Units in a district in Tamil Nadu, South India. All babies with gestational age at birth of ≤36 weeks and a birth weight (BW) of ≤1900 g with a follow-up period of at least 6 months were enrolled for the study. Neonatal and maternal risk factors were assessed and univariate and multivariate logistic regression analysis performed to examine the predictors of ROP. RESULTS: A total of 325 infants were screened. ROP was identified in 210 eyes of 106 (32.6%) babies with severe ROP (stage ≥3 ROP) occurring in 14 (13.2%) babies. Low BW (LBW) was the only significant risk factor for ROP on multivariate logistic regression analysis. The mean BW was 1285 and 1452 g for babies with and without ROP, respectively. Treatment was indicated in 22 eyes of 14 (13.2%) infants. CONCLUSIONS: The incidence of ROP was fairly high and strongly associated with LBW. A relatively low incidence of severe ROP was, however, observed. More effort is, therefore, required towards the prevention of preterm births while the present gains in neonatal care should be sustained to reduce the incidence of ROP and thus childhood blindness in the country.

A rare case of overlapping Sturge-Weber syndrome and Klippel-Trenaunay syndrome associated with bilateral refractory childhood glaucoma.

A 6-year-old girl presented with blurred vision and was found to have elevated intraocular pressure (IOP) and glaucomatous optic disc damage in both eyes. She also displayed capillary malformations on the face (port-wine stain), upper back and all four limbs, angiomatosis in the brain and had hypertrophy of the left upper and lower limbs typical of overlapping Sturge-Weber syndrome and Klippel-Trenaunay syndromes. She was initially managed with IOP lowering topical medications but required trabeculectomy in the right eye followed by Ahmed valve implantation in both eyes. Despite multiple measures over a 7-year period, her IOP still remained uncontrolled with gradual progression of the glaucomatous damage. This case exhibits a very rare occurrence of overlapping syndromes reported only a handful of times in literature. Most cases with Sturge-Weber syndrome have ipsilateral glaucoma affecting the eye on the same side as the port-wine stain. This case presented with bilateral refractory childhood glaucomas, which is exceedingly rare.

Effects of Laparoscopic Sleeve Gastrectomy on Central Obesity and Metabolic Syndrome in Indian Adults- A Prospective Study.

INTRODUCTION: Increasing incidence of obesity in Indian population has led to an exponential rise in the number of bariatric operations performed annually. Laparoscopic Sleeve Gastrectomy (LSG) has been proposed to cause rapid remission of Type 2 Diabetes Melitus (T2DM) and metabolic syndrome in a weight loss independent manner. AIM: To evaluate the effects of LSG on metabolic syndrome and central obesity in morbidly and severely obese Indian adults. Material and Methods: Study was conducted on 91 morbidly obese [Body Mass Index (BMI)>40 kg/m2] and severely obese (BMI>35 kg/m2) individuals who were suffering from diabetes, hypertension or dyslipidemia. The patients were followed up for six months and the trends of glycaemic control, mean blood pressure, lipid profile, weight loss parameters and changes in parameters of central obesity were studied. RESULTS: Weight loss was significant at three months postsurgery and was sustained through six months. There was significant improvement in glycaemic control leading to reduction in need for oral hypoglycaemic agents or insulin in majority of them and even discontinuation of these medications in few patients. Hypertension and dyslipidemia also showed an improving trend through six months postsurgery. There was a significant impact on reduction of central obesity in these patients as marked by significant reduction in waist to hip ratio. CONCLUSION: LSG produces sustainable weight loss with significant improvement in glycaemic status and control of metabolic syndrome in severe to morbidly obese patients. LSG is also efficacious in reducing central obesity in Indian population which is a major depressive ailment amongst obese individuals.

Custom-designed high-density conformal planar multielectrode arrays for brain slice electrophysiology.

Multielectrode arrays have enabled electrophysiological experiments exploring spatio-temporal dynamics previously unattainable with single electrode recordings. The finite number of electrodes in planar MEAs (pMEAs), however, imposes a trade-off between the spatial resolution and the recording area. This limitation was circumvented in this paper through the custom design of experiment-specific tissue-conformal high-density pMEAs (cMEAs). Four configurations were presented as examples of cMEAs designed for specific stimulation and recording experiments in acute hippocampal slices. These cMEAs conformed in designs to the slice cytoarchitecture whereas their high-density provided high spatial resolution for selective stimulation of afferent pathways and current source density (CSD) analysis. The cMEAs have 50 or 60 microm center-to-center inter-electrode distances and were manufactured on glass substrates by photolithographically defining ITO leads, insulating them with silicon nitride and SU-8 2000 epoxy-based photoresist and coating the etched electrode tips with gold or platinum. The ability of these cMEAs to stimulate and record electrophysiological activity was demonstrated by recording monosynaptic, disynaptic, and trisynaptic field potentials. The conformal designs also facilitated the selection of the optimal electrode locations for stimulation of specific afferent pathways (Schaffer collaterals; medial versus lateral perforant path) and recording the corresponding responses. In addition, the high-density of the arrays enabled CSD analysis of laminar profiles obtained through sequential stimulation along the CA1 pyramidal tree.