Operations on the colon without preoperative oral antibiotic therapy

The ideal preparation of the intestine prior to elective colonic resection has been a controversial subject. With the development of new and more effective antibiotics, many modalities of intestinal preparation preoperatively have been used in an effort to reduce the number of infectious complications. Mechanical cleansing of the intestine, when accompanied by perioperative parenteral antibiotics, is adequate preparation prior to resection of the intestine. One hundred consecutive operations upon the colon by one surgeon were the subject of this retrospective study. Approximately 70 per cent of the operations were for carcinoma and the remainder for inflammatory disease. Preparation consisted of the administration of cathartics and saline solution enemas combined with a liquid diet for 48 hours prior to operation. Perioperative parenteral antibiotic therapy was given for 48 to 72 hours or as long as intravenous fluids were administered. All anastomoses were the open, two layer type, using nonabsorbable suture material. All abdominal incisions were closed primarily. There were no operative deaths, anastomotic leaks, intra-abdominal abscesses or fistulas. There were six instances of wound infection. Our results with this type of management compare favorably with those of other surgeons using various modes of preoperative oral antibiotic therapy and suggest that oral preoperative antibiotic therapy may not be necessary in elective operations on the colon.

The conformational properties of some fragments of the peptide hormone somatostatin

The conformational properties of some somatostatin fragments have been studied using high resolution NMR and semi-empirical calculations. The fragments are Thr10-Phe11, Phe11-Thr12, Thr10-Phe11-Thr12 and Thr10-Phe11-Thr12-Ser13. The results of high resolution 1H and 13C NMR using dimethylsulfoxide and 2H2O as solvents, combined with a new method for determining dihedral angles phi and psi from 13C and 1H spin lattice relaxation times are presented. A marked inequivalence of the two Thr10,12 residues is attributed to a shielding of the the Thr10 side chain by the Phe11 aromatic ring. The calculations show the existence of extended and folded low energy conformations in the tri and tetrapeptide. Only the folded structures give the observed shielding of Thr10. A temperature study of the tri and the tetrapeptide indicates that the folded structures are energetically the most favorable conformations at room temperature in dimethylsulfoxide. Increasing temperature reduces the nonequivalence of the Thr residues towards the differences that are observed in 2H2O. A detailed comparison of 3JalphaNH coupling constants and relaxation time measurements with the calculated conformations gives in general good agreement between both approaches. It is concluded that in these linear peptides, although several quite different low energy conformations exist, some of them are predominant. The continuity of both NMR parameters and calculated low energy conformations, when going from the smaller to the larger peptides, demonstrates the existence of structural properties far from the "random conformation".

[Anaesthesia. Resuscitation problems arising from the surgical treatment of chemodectomas in the carotid fork (author's transl)]

Chemodectomas in the carotid fork are rare and usually benign tumours. Their removal by surgery creates certain problems in terms of operating technique since they are, anatomically, awkwardly situated. An additional problem arises from loss of blood resulting from their removal and possible cardiac disturbance which might affect the functioning of the carotid sinus should the tumours have been situated in this region. Furthermore, the possible eventuality of having to clamp the internal carotid for a short or even long time, should the operation require it, presupposes a perfect knowledge of the patient's cerebral circulation. Hence, therefore, the necessity of a verification of this circulation by centrolateral carotid arteriography to confirm the permeability of the circle of Willis and a potentially good supply of blood when the blood in the region of the tumour is restricted. It is equally necessary to have a complete record of the general state of the patient's cardiovascular, circulatory, respiratory, renal and neurological conditions. These must, within certain limits, be deemed satisfactory before the decision to operate is taken. Indeed, it is these conditions that will determine the per-operative as well as the post-operative condition of the patient.

Occurrence of tryptophan in the enzymically active site of diphtheria toxin fragment A

Tryptophan residues of diphtheria toxin fragment A have been modified by 2-hydroxy-5-nitrobenzyl bromide. Fragment A loses its ability to inactivate ADP-ribosylation of the elongation factor 2, as a function of the number of residues modified. Modification of one tryptophan residue provides a dramatic loss of enzymic activity suggesting the presence of one essential residue of this type in fragment A. Examination of fingerprint maps of chymotryptic peptides of fragment A after reaction with 2-hydroxy-5-nitrobenzyl bromide allows us to identify this tryptophan residue at position 153 of the amino acid sequence. ORD and CD experiments joined to immunochemical studies seem to exclude the possibility that the observed decrease in the enzymic activity may be attributed to a conformational change. Finally, results of nicotinamide-adenine dinucleotide-binding measurements suggest that tryptophan 153 would be concerned with the elongation factor 2 binding site or with the catalytic site itself.

Monitoring heparin therapy with the activated partial thromboplastin time

Difficulties associated with the whole blood clotting time (W.B.C.T.) as a method of monitoring heparin therapy have led to the investigation of the activated partial thromboplastin time (A.P.T.T.) as an alternative. The conclusion is reached that the latter procedure possesses several advantages. Using the method described and a citrate-preserved blood sample collected just prior to the administration of the next serial dose of heparin, the suggested therapeutic duration of the A.P.T.T. is 70 seconds or twice the mean control value. A practical range for this method is 60 to 70 seconds.

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Intragastric pressures in pylorus-ligated mice

The relationship between circulation, intragastric pressure and ulcer formation, was investigated in the pylorus-ligated mouse. Eight hours after pyloric ligation, the animals were etherized and intragastric pressures measured. The stomach contents were aspirated and determined. The stomach was opened and number and location of ulcers noted. In another series of animals, India ink was injected into the stomach through the aorta. Injected stomachs of normal and pylorus-ligated mice were cleared with the Spalteholtz method and examined with a dissecting microscope. In the stomachs of normal and of pylorus-ligated mice, areas of lesser vascularity were seen, and in these areas most ulcers appeared to occur.