Surgical implications of variations in hand collateral circulation: anatomy revisited

OBJECTIVES

One of the risks associated with harvesting the radial artery is hand ischemia. Accordingly, this study investigated the variations of the hand collateral circulation.

METHODS

Fifty hands of cadavers were examined. Variations of the palmar arches were recorded. A classic superficial palmar arch was defined as direct continuity between the ulnar artery and the superficial palmar branch of the radial artery. A classic complete deep palmar arch was defined as direct continuity between the radial artery and the deep branch of the ulnar artery.

RESULTS

A classic superficial palmar arch was found in 10% (5/50) of hands, and a classic complete deep palmar arch was found in 90% (45/50) of hands. The superficial palmar branch of the ulnar artery supplied blood to all fingers in 66% (33/50) of hands. Although the superficial palmar branch of the ulnar artery was continuous with the radial artery in only 34% (17/50) of hands (including the classic type of superficial palmar arch), every hand had at least one major branch connecting the radial and ulnar arteries.

CONCLUSIONS

Variations in the terminations of the radial and ulnar arteries are common. Although the classic type of superficial palmar arch occurs relatively infrequently, there is always a significant anastomosis between the radial and the ulnar artery in the hand. This anatomic study confirms the presence of a collateral supply in the hand. In the absence of vascular disease, harvesting the radial artery should be regarded as a safe procedure.

Prophylactic intravenous mannitol and normal saline in patients with poor renal function prior to cardiac surgery: Time for a multicentre trial?

BACKGROUND

Postoperative acute renal failure requiring dialysis has a poor prognosis, which has remained unaltered for 50 years. Therefore, in cardiac surgical patients at increased risk of postoperative oliguric acute renal failure (preoperative serum creatinine >0.13 mmol/L), we assessed the use of prophylactic intravenous (i.v) 20% mannitol and normal saline therapy in addition to traditional methods of therapeutic renal support.

METHODS

Seventy-five patients with a mean preoperative serum creatinine of 0.192 mmol/L received i.v. 20% mannitol and normal saline pre-, intra- and postoperatively. This treatment was continued postoperatively until serum creatinine returned to baseline.

RESULTS

No patient required dialysis, no patient died, developed a myocardial infarction nor a stroke in the first 30 days post-surgery. Serum creatinine and urea increased to a mean peak on day 3 of 0.233 +/- 94 and 24.6 +/- 13 mmol/L, respectively. However, all patients maintained a high urine output (>2 L/day) and no patient required haemodialysis.

CONCLUSION

Therapy with i.v. 20% mannitol and normal saline appears safe and effective in maintaining a diuresis and may avoid the need for dialysis. A randomised controlled trial of this treatment in patients at increased risk of postoperative acute renal failure is warranted.

Catabolism of leukotriene B5 in humans

Human neutrophils, enriched by dietary supplementation with eicosapentaenoic acid, form leukotriene (LT)B5 in addition to LTB4 upon stimulation. LTB5 is one order of magnitude less biologically active than the potent chemokinetic and chemoattractant LTB4. Catabolites of LTB5 have not yet been characterized in vitro and ex vivo. It is unknown whether catabolism of LTB5 interferes with catabolism of LTB4. This report describes catabolism of LTB5 to 20-OH-LTB5, which in turn is catabolized to 20-COOH-LTB5. The structures of the two catabolites were established by UV-absorbance, behavior on reverse-phase high-performance liquid chromatography, enzymatic analysis of human neutrophils, and gas chromatography-mass spectrometry. In vitro, formation of LTB4 was delayed and formation of its catabolites was depressed by exogenous eicosapentaenoic acid. By supplementing the diet of six volunteers with 5 g eicosapentaenoic acid/day for 7 days, eicosapentaenoic acid quadrupled in neutrophil phospholipid fatty acids. Consequently, LTB5, 20-OH-LTB5, and 20-COOH-LTB5 were detected ex vivo. In contrast to the findings in vitro, however, levels of LTB4, 20-OH-LTB4, and 20-COOH-LTB4 were unaltered by the dietary intervention. Thus, in vitro, but not ex vivo, addition of eicosapentaenoic acid, and subsequent formation of LTB5, impeded catabolism of proinflammatory LTB4.

Expression of c-sis and other cellular proto-oncogenes in human sarcoma cell lines and biopsies

Six biopsies (4 of human fibrosarcomas, 1 of a B-cell lymphoma and 1 of a normal lymph node from a melanoma patient) and 6 cell lines (derived from 5 different human osteosarcomas and from 1 rhabdomyosarcoma), together with control cells, were examined for the expression of c-sis, c-fos and c-myc. The expression of c-sis/PDGF-B-related proteins was also examined in cultured cells (not in biopsies). In situ hybridization studies further showed that the occurrence and level of expression of c-sis mRNA and c-sis/PDGF-B-related proteins were significant in the tumor cells. Expression of c-fos and c-myc mRNA did not correlate with c-sis expression. Southern blot analysis of c-sis, c-fos and c-myc of 20 DNAs of cell lines derived from human sarcoma or biopsies showed an identical pattern for BamH1 and EcoR1 restriction fragments of c-sis (except for 1 fibrosarcoma biopsy), implicating no gene rearrangement as a cause of enhanced proto-oncogene expression. The nucleotide sequence of c-sis is highly homologous to that of the viral v-sis oncogene which is capable of transforming infected cells. We conclude that enhanced expression of c-sis in the sarcomas we have examined is involved in the initiation and/or maintenance of the cell transformed state.