Intronization enhances expression of S-protein and other transgenes challenged by cryptic splicing

The natural habitat of SARS-CoV-2 is the cytoplasm of a mammalian cell where it replicates its genome and expresses its proteins. While SARS-CoV-2 genes and hence its codons are presumably well optimized for mammalian protein translation, they have not been sequence optimized for nuclear expression. The cDNA of the Spike protein harbors over a hundred predicted splice sites and produces mostly aberrant mRNA transcripts when expressed in the nucleus. While different codon optimization strategies increase the proportion of full-length mRNA, they do not directly address the underlying splicing issue with commonly detected cryptic splicing events hindering the full expression potential. Similar splicing characteristics were also observed in other transgenes. By inserting multiple short introns throughout different transgenes, significant improvement in expression was achieved, including >7-fold increase for Spike transgene. Provision of a more natural genomic landscape offers a novel way to achieve multi-fold improvement in transgene expression.

Evaluation of versatility of use of island first dorsal metacarpal artery flap in reconstruction of dorsal hand defects.

BACKGROUND: Posttraumatic dorsal hand defects with exposed tendons and/or bones represent a challenge to reconstructive surgeons. Many options are suggested ranging from local, regional, distant up to free flaps. First dorsal metacarpal artery island flap was commonly prescribed for reconstructing the thumb or first web space defects. METHODS: During a 30 month's period, 23 patients, 15 males aged between 17 and 48 years and 8 females aged between 18 and 36 years presented by posttraumatic dorsal hand defects. Of them 18 had both exposed tendons and bones while 5 had exposed tendons only. The defects dimensions ranged between 3 × 4 cm and 4.5 × 6 cm. All defects were reconstructed by using a single stage first dorsal metacarpal artery island flaps. RESULTS: All flaps survived completely without complication during the mean follow up period of 2 years. All patients were very satisfied both functionally and aesthetically by the procedure. CONCLUSION: Island first dorsal metacarpal artery flap is a good option for reconstructing mild to moderate dorsal hand defects with acceptable functional and cosmetic results.

Helix free otoplasty for correction of prominent ear.

BACKGROUND: Prominent or bat ear is not uncommon deformity as it affecting 5% of population. Plenty of procedures were reported for its correction. Being plenty means it is still a subject of research. The current procedures could be summarized as cartilage sparing and cartilage splitting ones. METHODS: During a period of 35 months a total of 31 patients were presented with bilateral prominent ears so the included a total of 62 ears. Their average age was 8 years (ranging from five to 18 years). All deformities were corrected using helix free otoplasty technique which included skin paddle excision, separation of helical cartilage (hence the name helix free), anterior scoring, backward folding, mattress and simple suturing of the folded cartilage, proper definition of antitragus and earlobe and concha-mastoid sutures. Outcomes including patient's and/or guardians' satisfaction were determined. RESULTS: The postoperative period was uneventful except two cases that developed early postoperative hematomas, one case shows late postoperative antihelical fold irregularity in one ear and other case developed ill defined superior helix in one ear. The average follow up period of two years shows no recurrences. Almost all patients (96.85%) and their guardians were satisfied with the aesthetic results while only one (3.2%) was dissatisfied. CONCLUSION: Helical free otoplasty technique addresses the deformity through a posterior approach with under vision correction. It has very low incidence of complications, high patient's satisfactions, no visible scars and no recurrences. It is a simple, short duration procedure, reliable and good option for correction of prominent ear.