Surviving mossy cells enlarge and receive more excitatory synaptic input in a mouse model of temporal lobe epilepsy

Numerous hypotheses of temporal lobe epileptogenesis have been proposed, and several involve hippocampal mossy cells. Building on previous hypotheses we sought to test the possibility that after epileptogenic injuries surviving mossy cells develop into super‐connected seizure‐generating hub cells. If so, they might require more cellular machinery and consequently have larger somata, elongate their dendrites to receive more synaptic input, and display higher frequencies of miniature excitatory synaptic currents (mEPSCs). To test these possibilities pilocarpine‐treated mice were evaluated using GluR2‐immunocytochemistry, whole‐cell recording, and biocytin‐labeling. Epileptic pilocarpine‐treated mice displayed substantial loss of GluR2‐positive hilar neurons. Somata of surviving neurons were 1.4‐times larger than in controls. Biocytin‐labeled mossy cells also were larger in epileptic mice, but dendritic length per cell was not significantly different. The average frequency of mEPSCs of mossy cells recorded in the presence of tetrodotoxin and bicuculline was 3.2‐times higher in epileptic pilocarpine‐treated mice as compared to controls. Other parameters of mEPSCs were similar in both groups. Average input resistance of mossy cells in epileptic mice was reduced to 63% of controls, which is consistent with larger somata and would tend to make surviving mossy cells less excitable. Other intrinsic physiological characteristics examined were similar in both groups. Increased excitatory synaptic input is consistent with the hypothesis that surviving mossy cells develop into aberrantly super‐connected seizure‐generating hub cells, and soma hypertrophy is indirectly consistent with the possibility of axon sprouting. However, no obvious evidence of hyperexcitable intrinsic physiology was found. Furthermore, similar hypertrophy and hyper‐connectivity has been reported for other neuron types in the dentate gyrus, suggesting mossy cells are not unique in this regard. Thus, findings of the present study reveal epilepsy‐related changes in mossy cell anatomy and synaptic input but do not strongly support the hypothesis that mossy cells develop into seizure‐generating hub cells. © 2014 Wiley Periodicals, Inc.     

Comparative role of intravitreal ranibizumab versus bevacizumab in choroidal neovascular membrane in age-related macular degeneration

Context:

Ranibizumab and bevacizumab are used widely for treating patients with choroidal neovascular membrane (CNVM) secondary to age-related macular degeneration (AMD).

Aims:

To determine and compare the efficacy and safety of intravitreal ranibizumab and bevacizumab in treatment of CNVM due to AMD.

Settings and Design:

Prospective comparative case series carried out in an eye institute and eye department of a hospital in Kolkata, India.

Materials and Methods:

One hundred and four eyes with CNVM due to AMD were randomized into two groups. Group A (n=54; 24 occult) received monthly intravitreal ranibizumab injections (0.5 mg in 0.05 ml) and Group B (n=50; 22 occult) received monthly bevacizumab injections (1.25 mg in 0.05 ml) for 3 consecutive months and then as per study criteria. Data analysis done using SPSS software. P-value of <0.05 was considered statistically significant.

Results:

The mean best corrected visual acuity (BCVA) in the ranibizumab group increased from 58.19 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at baseline to 64 ETDRS letters at month 3 (P<0.001). In bevacizumab group mean BCVA increased from 56.80 to 61.72 ETDRS letters at month 3 (P<0.001). At the end of 18 months, there was no statistically significant difference between groups A and B with respect to change in BCVA (P=0.563) or central macular thickness (CMT; P=0.281), as measured by optical coherence tomography (Stratus OCT 3000). No significant sight-threatening complications developed.

Conclusions:

Ranibizumab and bevacizumab are equally safe and efficacious in treating CNVM due to AMD.     

Inactivation of human mutL homolog 1 and mutS homolog 2 genes in head and neck squamous cell carcinoma tumors and leukoplakia samples by promoter hypermethylation and its relation with microsatellite instability phenotype

BACKGROUND: A subset of head and neck squamous cell carcinoma (HNSCC) exhibits a microsatellite instability (MIN) phenotype. The authors correlated alterations in the mismatch-repair genes human mutL homolog 1 (hMLH1) and human mutS homolog 2 (hMSH2) in primary head and neck squamous cell carcinoma (HNSCC) tumors and in samples of leukoplakia with the MIN phenotype. METHODS: One hundred twenty-three paired HNSCC normal and tumor tissues and 27 leukoplakia samples were examined for hypermethylation of hMLH1 and hMSH2 promoters. The hypermethylation status of the tissues was confirmed by expression studies. Sixty-three of 123 randomly selected tumors and all 27 leukplakia samples were genotyped with 8 microsatellite markers to determine MIN. RESULTS: Fifty percent of HNSCC tumors and 63% of leukoplakia samples harbored hypermethylation at either or both hMLH1 and hMSH2 promoters. Normal tissues adjacent to methylation-positive tumors also demonstrated hypermethylation of both promoters at a high frequency (25%). A positive correlation between tobacco habit and promoter hypermethylation was observed (P = .001). A correlation was observed between MIN and the frequency of promoter hypermethylation in the leukoplakia samples, but no such trend was observed in the HNSCC tumors. It is noteworthy that patients who had a high frequency of MIN-positive tumors exhibited hypermethylation in both the affected tissues and the adjacent normal tissues (P = .007). Patients with a tobacco habit who had promoter hypermethylation at both the affected tissues and the adjacent normal tissues had tumors that mostly were MIN positive (P = .047). CONCLUSIONS: The current results suggested that tobacco-addicted individuals are more susceptible to promoter hypermethylation of hMLH1 and hMSH2 and that, if such hypermethylation occurs in the normal squamous epithelium of the head and neck region, then those tissues are likely to develop into tumors that involve the MIN pathway.     

Foreign bodies in ENT in a teaching hospital in Eastern India

Objective

To evaluate the nature, common sites, modes of presentation of various foreign bodies (FB) in Ear, Nose and Throat (ENT).

Materials and methods

Observational retrospective study carried out at Vivekananda Institute of Medical Sciences, Ramakrishna Mission Seva Pratishthan. The study period was between Jan 2006 to Jan 2007. The information obtained from the hospital record books.

Results

Four hundred and eighty-two patients presented in the Department of Otorhinolaryngology of Vivekananda Institute of Medical Sciences, in the study period with FB in their ENT. Out of 482 pts, the commonest location of FB was to be in throat with 302 pts (62%) followed by ear with 119 pts (25%) and nose 61 pts (13%). Amongst the FB in throat the commonest was fish bone and the commonest site being tonsils. Artificial denture accounted for a significant number of 13 (4.3%). External auditory canal was the commonest site of FB lodgment in ear found in 118 patients (99.16%). Nasal FB were found in 61 patients; more common in pediatric age group (98.36%).

Conclusion

From this study we have found that FB lodgement is a very common complaint with which patients come to otolaryngologist. The commonest site of FB lodgement is in the throat. Most of the FB could be removed in emergency room (ER) with or without Local Anesthesia.