Synthesis of Hydroxamic Acid Derivatives Using Blocked (Masked) O-Isocyanate Precursors.

Hydroxamic acids are present in a several pharmaceuticals and agrochemicals. Synthetic strategies providing access to hydroxamic acid derivatives remain limited, typically requiring the use of nucleophilic hydroxylamine reagents. Herein, a synthesis of hydroxamates from unactivated carboxylic acids is reported making use of rare blocked (masked) O-substituted isocyanates. The applicability of this transformation was highlighted by targeting the synthesis of vorinostat and belinostat derivatives.

The influence of palatal harvesting technique on the donor site vascular injury: A split-mouth comparative cadaver study.

BACKGROUND: The aim of this study was to evaluate the influence of two harvesting approaches on the donor site vascular injury. METHODS: A split-mouth cadaver study was designed on 21 fresh donor heads. Every hemi-palate was assigned to receive the trap-door harvesting technique (TDT) or the epithelialized free gingival graft harvesting technique (FGGT). A soft tissue graft was harvested from each side for histology analyses. Betadine solution was used to inject the external carotid artery and a collagen sponge was positioned over the harvested area to compare the amount of "leakage." RESULTS: The mean leakage observed was 16.56 ± 3.01 µL in the FGGT-harvested sites, and 69.21 ± 7.08 µL for the TDT group, a ratio of 4.18 (P < 0.01). Regression analyses demonstrated a trend for more leakage at thinner palatal sites for the FGGT group (P = 0.09), and a statistically significant correlation for the TDT-harvest sites (P = 0.02). Additionally, a shallow palatal vault height (PVH) was associated with a higher leakage in both harvesting groups (P = 0.02). The histomorphometric analyses revealed that grafts harvested with TDT exhibited a significantly higher mean number of medium (ø = 0.1 to 0.5 mm, P = 0.03), and large vessels (ø ≥ 0.5 mm, P = 0.02). CONCLUSIONS: Within the limitations of the present research, the TDT resulted in a significantly higher leakage than the FGGT, which was also correlated with the histology analyses where a greater number of medium and large vessels were observed in the harvested grafts.

Formation of Complex Hydrazine Derivatives via Aza-Lossen Rearrangement.

The development of a broadly applicable procedure for the aza-Lossen rearrangement is reported. This process converts amines into complex hydrazine derivatives in two steps under safe, mild conditions. This method allows the chemoselective formation of N-N bonds, resulting in the synthesis of cyclic and acyclic products while avoiding side reactions of the amphoteric (ambident) nitrogen-substituted isocyanate intermediate.

Incidental Anatomic Finding of Celiacomesenteric Trunk Associated with 'Nutcracker Phenomenon,' or Compression of the Left Renal Vein.

BACKGROUND Celiacomesenteric trunk (CMT) is a very rare anatomic finding in which the celiac artery and the superior mesenteric artery (SMA) originate from the abdominal aorta through a common trunk. Clinical associations with CMT include arterial aneurysm, thrombosis, and celiac artery compression. However, an association between CMT and abdominal venous congestion caused by left renal vein compression, or 'nutcracker phenomenon,' has not been previously reported. CASE REPORT A 91-year-old woman, who died from a cerebrovascular accident (CVA), underwent a cadaveric examination at our medical school. On examination of the abdomen, there was an incidental finding of CMT. The arterial and venous diameters were measured, and vascular histopathology was undertaken. The vascular anatomy was consistent with CMT type 1-b. Nutcracker phenomenon (NCP) (left renal vein compression) was seen anatomically as dilatation and engorgement of the left renal vein, relative to the right renal vein (10.77±0.13 mm vs. 4.49±0.56 mm, respectively), and dilatation and engorgement of the left ovarian vein, relative to the right ovarian vein (4.37±0.15 mm vs. 1.06±0.09 mm, respectively) with left ovarian varicocele. The aortoceliac angle (ACA) and the aortomesenteric angle (AMA) approached zero degrees. CONCLUSIONS We have described a rare anatomic finding of CMT that created an acute AMA and NCP. Awareness of this rare association between CMT and NCP by clinicians, vascular surgeons, and radiologists may be of value in the future evaluation and surgical management of patients who present clinically with 'nutcracker syndrome.'

Branching patterns and localization of the common fibular (peroneal) nerve: an anatomical basis for planning safe surgical approaches.

PURPOSE: Given the severity and incidence of injury to the common fibular (peroneal) nerve (CFN), there is a need to further clarify its anatomical location and branching patterns. This project attempts to consolidate current anatomical understanding of this nerve and provide physicians with reproducible measurements regarding the CFN and its branches. METHODS: Dissections were performed on 50 specimens (28 cadavers), both fresh and preserved. The CFN was dissected from its emergence from the fibular tunnel to its anterior tibial recurrent nerve (ATRN), superficial fibular nerve (SFN), and deep fibular nerve (DFN) branches. The CFN branching patterns were assessed and all variations were categorized into four types. RESULTS: Several significant relationships were identified between observable traits and key anatomical characteristics of the CFN. A significant correlation was found between fibular length and distance from the tip of the fibula to the DFN/ATRN branch, as well as between fibular length and distance from the tibial tuberosity to the SFN/DFN and DFN/ATRN branches. An association was identified between length of exposed sub-cutaneous CFN and height. Thickness of the biceps femoris tendon correlated significantly with BMI. CONCLUSIONS: These findings allow physicians to better assess a patient's individual CFN anatomy based on correlations with measureable physical traits and will contribute to anatomic education and successful completion of various surgical, anesthetic, and physical therapy procedures.

Impact of underestimating the effects of cold temperature on motor vehicle start emissions of air toxics in the United States.

Analyses of U.S. Environmental Protection Agency (EPA) certification data, California Air Resources Board surveillance testing data, and EPA research testing data indicated that EPA's MOBILE6.2 emission factor model substantially underestimates emissions of gaseous air toxics occurring during vehicle starts at cold temperatures for light-duty vehicles and trucks meeting EPA Tier 1 and later standards. An unofficial version of the MOBILE6.2 model was created to account for these underestimates. When this unofficial version of the model was used to project emissions into the future, emissions increased by almost 100% by calendar year 2030, and estimated modeled ambient air toxics concentrations increased by 6-84%, depending on the pollutant. To address these elevated emissions, EPA recently finalized standards requiring reductions of emissions when engines start at cold temperatures.