Genomic expression changes induced by topical N-acetyl glucosamine in skin equivalent cultures in vitro

N-acetyl glucosamine (NAG) has been shown to be effective in reducing the appearance of hyperpigmented spots. From published in vitro mechanistic testing, glucosamine inhibits enzymatic glycosylation, a required processing step in converting inactive human pro-tyrosinase to the active tyrosinase, a key enzyme in the production of melanin. There is also published literature discussing the anti-inflammatory and antioxidant properties of glucosamine compounds. To identify additional mechanisms by which NAG might affect melanin production, an in vitro genomics experiment was conducted in SkinEthic skin equivalent cultures, which were topically dosed with NAG vs. a vehicle control. Relative to vehicle, NAG reduced melanin production, and the expression of several pigmentation-relevant genes were affected (down-regulated or up-regulated) by NAG treatment. Thus, there are several mechanisms that may be operative in the observed pigmentation effects.     

Laparoscopic versus open left lateral hepatic sectionectomy: A comparative study

Background

Laparoscopic liver surgery has been difficult to popularize. High volume liver centres have identified left lateral sectionectomy (LLS) as a procedure with potential for transformation into a primarily laparoscopic procedure where surgeons can safely gain proficiency.

Methods

Forty-four patients underwent either laparoscopic (LLLS) or open (OLLS) left lateral sectionectomy (of segments II/III) for focal lesions at Southampton General Hospital.

Results

OLLS and LLLS groups were matched for age, sex and tumour types resected. Median operative time in the LLLS group was 180 (40–340) min and 155 (110–330) min in the OLLS group (p = 0.885) with median intra-operative blood loss in the LLLS group 80 (25–800) ml versus a larger 470 (100–3000) ml; p = 0.002 for patients receiving OLLS. Post-operative stay was also shorter in the LLLS group (3.5 (1–6) days) compared to the OLLS group (7 (3–12) days; p < 0.001). Resection margin was not different in the two groups (11 (1.5–30) mm (LLLS) versus 12 (4–40) mm (OLLS); p = 1) and neither was the complication rate (13% for LLLS versus 25% for OLLS; p = 0.541). There were no conversions to open in the LLLS group and no deaths in either group at 90 days. Between the first and second 12 LLLS the median operative time fell from 240 (70–340) min to 120 (40–120) min; p = 0.005 as well as median post-operative hospital stay from 4.5 (2–6) days to 2 (1–4) days, p = 0.001.

Conclusion

LLLS is a viable alternative to OLLS with potential improvements in intra-operative blood loss and shorter hospital stay without adversely affecting successful resection or complication rates. Larger prospective studies are required to explore this new avenue in laparoscopic liver surgery.     

Statistical prediction of cardiac risk in patients who undergo vascular surgery

Since August 1982, an extensive computerized data base has been developed on all patients admitted to the Division of Vascular Surgery at the Ottawa Civic Hospital. For each patient, 180 variables are recorded, including information about preoperative risk factors and postoperative complications. Since cardiac complications are a major cause of mortality and morbidity, the data file has been used to study postoperative cardiac complications in patients who undergo arterial reconstructive operations. Between August 1982 and December 1983, 353 artery repairs were performed, excluding ruptured aneurysms. Cardiac complications developed following surgery in 56 patients. Risk factors were initially studied using contingency table analysis. Four of these factors were found to be significant: electrocardiographic evidence of previous myocardial infarction (p = 0.0003), nonspecific ST-segment changes (p = 0.0007), New York Heart Association classification of symptoms (p = 0.0003) and age (p = 0.01). A further statistical study was based upon multiple logistic regression. The authors believe that the identification of a high-risk group, using these criteria, is helpful in selecting patients for intensive preoperative investigation, including coronary arteriography.     

Antitumor agents, 135. Structure and stereochemistry of polacandrin, a new cytotoxic triterpene from Polanisia dodecandra.

A new dammarane triterpene, polacandrin [1], has been isolated from Polanisia dodecandra. The structure of 1 was established as 1 beta, 3 alpha, 12 beta, 25-tetrahydroxy-20(S),24(S)-epoxydammarane by chemical and spectroscopic methods, which included the concerted application of a number of 2D nmr techniques that involved 1H-1H COSY, HETCOR, NOESY, and long-range HETCOR. Single-crystal X-ray analysis of polacandrin pentahydrate verified the complete structure and stereochemistry. Polacandrin showed potent cytotoxicities against KB (ED50 = 0.60 microgram/ml), P-388 (ED50 = 0.90 microgram/ml), and RPMI-7951 (ED50 = 0.62 microgram/ml) tumor cells.