Recent Advances in Organoselenium Catalysis.

Organoselenium chemistry has developed as an important tool in the field of synthetic and medicinal chemistry. Various organoselenium reagents have been developed and used successfully to achieve different organic transformations such as selenocyclizations, oxyselenenylations, selenoxide eliminations, etc. Additionally, organoselenium reagents' potential is not limited to their use as stoichiometric reagents, but they have been successfully used as organocatalysts in a number of synthetic transformations. Various organic and inorganic oxidants have been identified as terminal oxidants to regenerate the active catalytic species. In this review article, the recent progress of organoselenium reagents in catalysis is being highlighted along with their asymmetric variants.

Submental Dermoid Cyst Mimicking Double Chin.

Dermoid cysts are developmental cysts, arising from entrapped midline ectodermal tissue lined by epidermis, with skin appendages present in the fibrous wall when the 1st and 2nd branchial arches of each side fuse and the entrapped tissues then undergo proliferation and cystic transformation. A 27-year-old male reported with a single large swelling in the submental region of 1-year duration, which was diagnosed as dermoid cyst after surgical excision using extraoral approach.

Tuberculous Infection and Exodontia: A Diagnostic & Treatment Dilemma.

Tuberculous infection is more common in developing countries which are often overlooked by most of the doctors due to improper medical case history. This causes further complications as they proceed with their procedure. Till date, in dentistry, 90 such cases have been reported in literature. Hence, a dentist should be suspecting preexisting tuberculous osteomyelitis or postextraction complications from such an infection in patients with a positive history of tuberculous infection. Diagnosis as such is often overlooked despite a high prevalence of the disease in high-burden countries such as India. We report this case because of the rarity of its clinical presentation, which was misdiagnosed as odontogenic problem instead of preexisting tuberculous osteomyelitis in the mandibular retromolar region.

Multiple impacted permanent teeth, an indicator for early detection of hypoparathyroidism: A rare case report.

Eruption is a process of continuous movement of the developing tooth bud from its developmental location to functional location. Teeth that cease to erupt before emergence to their functional position in the oral cavity are termed as impactions. In permanent dentition, third molars are the most frequently impacted teeth followed by the canines. When impaction involves few teeth, the condition is localized but when it involves multiple teeth, the condition becomes generalized and is often associated with some derangement of the normal physiological processes. Factors causing impactions may be localized, pertaining to the area or, systemic or, generalized including bone disorders such as cleidocranial dysplasia and/or some sort of endocrinological disturbance such as hypoparathyroidism. Hypoparathyroidism is a rare endocrinological disorder accompanied by anomalies of various systems including bones and teeth. The dental defects due to hypoparathyroidism may present as hypocalcemia, aplasia and/or hypoplasia, defects of mineralization, short and blunted roots, delayed eruptions, and clinically missing or impacted teeth. This report describes an interesting and unusual case where multiple impacted permanent teeth and retained primary teeth accompanied by other clinical manifestations in a 16-year-old female patient probed the clinicians for further investigations which, eventually, aided in early diagnosis of hypoparathyroidism.

Design of temperature-sensitive mutants solely from amino acid sequence.

Temperature-sensitive (Ts) mutants are a powerful tool with which to study gene function in vivo. Ts mutants are typically generated by random mutagenesis followed by laborious screening procedures. By using the Escherichia coli cytotoxin CcdB as a model system, simple procedures for generating Ts mutants at high frequency through site-directed mutagenesis were developed. Putative buried, hydrophobic residues are selected through analysis of the protein sequence. Residue burial is confirmed by ensuring that substitution of the residue by Asp leads to protein inactivation. At such sites, a Ts phenotype can typically be generated either by (i) substitution of two predicted, buried residues with the 18 remaining amino acids or (ii) introduction of Lys, Ser, Ala, and Trp at three to four predicted buried sites. By using these design strategies, 17 tight Ts mutants of CcdB were isolated at four predicted buried sites. The rules were further verified by making several Ts mutants of yeast Gal4 at residues 68, 69, and 70. No Ts mutants of either protein have been previously reported. Such Ts mutants of Gal4 can be used for conditional expression of a variety of genes by using the well characterized upstream-activating-sequence-Gal4 system.