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The biosynthesis of the constituent polypeptides of nitrogenase component I (Rj 1) in free-living cultures of Rhizobium japonicum (strain 110) was investigated under different growth conditions. Cells were pulse-labelled and the proteins analysed by one and two-dimensional gel electrophoresis. The positions of the constituent Rj 1 polypeptides were identified by co-electrophoresis with purified Rj 1 isolated from bacteroids of soybean nodules, and by comparison with an immunoprecipitate from a culture induced for nitrogenase. The synthesis of the proteins preceded any detectable enzyme activity and increased with time, reaching a maximum after 3 days. At this time, between 6 and 8% of the total sodium dodecyl sulfate-soluble protein synthesized was Rj 1. Exposure to air led to a dramatic decrease in the rate of Rj 1 synthesis, with almost complete regression after 20 min. In the presence of KNO3, there was no nitrogenase activity, but the proteins were present in similar amounts (7%) as the control culture. When mannitol and glycerol were used as the sole carbon sources, the amount of Rj 1 synthesized was extremely low.

Utilisation (uptake) of hydrogen gas by whole cells of Rhizobium japonicum was found to be influenced by the carbon source(s) present in the growth medium, with activity being highest in a medium containing sugars. Tricarboxylic acid cycle intermediates, such as malate, significantly reduced H2 utilisation. No reduction in the hydrogenase activity is observed when the enzyme is assayed directly by the tritium exchange method, indicating that the decrease in hydrogen uptake activity is not due to repression of hydrogenase biosynthesis. Cyclic AMP was found to alleviate the inhibition of H2 uptake by malate, and this requires new protein synthesis. Addition of chloramphenicol or rifampicin simultaneously with cyclic AMP eliminated the stimulation of H2 uptake in the malate medium. These results show that in R. japonicum cyclic AMP plays a major role in the regulation of H2 metabolism.

A new operation was designed to supplement the Kirschner operation for patients with locally advanced carcinoma of the esophagus and who, in addition, had had a gastrectomy for peptic ulcer disease. Bypass of the esophageal obstruction was by jejunal loop, and gastroesophageal reflux was prevented by fundoplication. Eighteen patients underwent this operation with a mortality of 27.8 per cent. Death occurred in one of the three patients with leakage of the esophagojejunal anastomosis. One patient had gangrene of the jejunal loop develop. Severe bronchopneumonia was the cause of death in all five. The functional result in the surviving patients was satisfactory and they lived for a mean period of 3.6 months postoperatively. It is not advocated that this operation replace the Kirschner operation, which we consider the operation of choice for locally advanced carcinoma of the esophagus, but as an alternative procedure in those patients in whom a previous gastric resection precluded a Kirschner operation.

Skeletal muscle tissues from many species of salmonid fish are known to exhibit a set of three of five isozymes for A4-type lactate dehydrogenase (L-lactate: NAD oxidoreductase, E.C. 1.1.1.27), but the genetic basis for this isozyme system has not previously been assessed. This isozyme system was purified to homogeneity from salmon (Oncorhynchus tshawytscha) and shown to be composed of two polypeptides. Aalpha and Abeta, in binomial tetrameric combinations. Amino acid analysis revealed that Aalpha and Abeta are closely related but genetically distinct proteins, and thus are coded for the recently duplicated structural loci. Catalytic studies on the purified intact salmon isozyme system and on the isozymically pure Aalpha4 and Abeta4 homotetramers from brown trout (Salmo trutta) revealed no significant differences in catalytic properties among these enzymes, suggesting equivalent catalytic function of Aalpha and Abeta. These results, in combination with studies on polypeptide and isozyme ratios, suggest that one of the duplicated loci in salmon may be drifting toward a nonfunctional state by accumulation of mutations in regulatory DNA rather than in the structural gene itself.

Over a 14-year period we treated 2,290 cases of non-malignant biliary tract conditions, and among them were 173 cases of acute suppurative cholecystitis, an incidence of 7.6%. A correct preoperative diagnosis of acute suppurative cholecystitis was made in only about half the cases because features of recurrent pyogenic cholangitis dominated the clinical picture on many occasions. The diagnosis was confirmed in all cases at operation. Cholecystectomy (88%) was performed whenever this was found to be safe, and cholecystostomy (12%) was carried out only in poor-risk patients or when operative difficulties were encountered. The overall mortality of operation was 5.8%. Old age, preoperative shock, delay of operation and the presence of free perforation affected the prognosis adversely.

Eight cases of subarachnoid hemorrhages are reported to illustrate the ability of CT to demonstrate thin, flat collections of subarachnoid blood clots and the importance of CT in localization of the bleeding site, especially in cases of multiple aneurysms. The major factors in the detection of these lesions are discussed on the basis of partial volume phenomenon.

A sensitive tritium exchange assay was applied to the Rhizobium system for measuring the expression of uptake hydrogenase in free-living cultures of Rhizobium japonicum. Hydrogenase was detected about 45 hours after inoculation of cultures maintained under microaerophilic conditions (about 0.1% O(2)). The tritium exchange assay was used to screen a variety of different strains of R. japonicum (including major production strains) with the findings that about 30% of the strains expressed hydrogenase activity with identical results being observed using an alternative assay based on uptake of H(2). The relative efficiency of intact soybean nodules inoculated with 10 different rhizobial strains gave results identical to those obtained using free-living cultures. The tritium exchange assay provides an easy, quick, and accurate assessment of H(2) uptake efficiency of intact nodules.

Nine cases of primary sarcoma of the jaw seen over a period of 14 years are presented. They consisted of four osteosarcomas, three fibrosarcomas, one myxosarcoma and one Ewing's sarcoma. The treatment of choice for osteosarcomas of the mandible is hemimandibulectomy with disarticulation at the temporomandibular joint. Bone graft reconstruction from the iliac crest should be done at a second stage. Palliative maxillectomy for extensive fibrosarcoma of the maxilla served to relieve one patient of local symptoms for more than a year. Myxosarcoma, a variant of fibrosarcoma, and Ewing's sarcoma of the jaw, are very rare conditions, and since these lesions are usually very extensive radiotherapy is the treatment of choice.

In patients with advanced carcinoma of the bladder not involving the trigone, radical total cystectomy with bladder replacement (replacement cystoplasty) using either the colon, ileum or stomach can be performed. In male patients, the prostatic urethra is always included in the resection so that the extent of radical surgery is not compromised. Thus the neobladder is anastomosed to the membranous urethra in these patients. In patients with contracted tuberculous bladder, the neobladder is anastomosed to the trigone after subtotal cystectomy (augmentation cystoplasty). The pattern of micturition is studied in 32 patients with cystoplasty after cystectomy. Emptying of the neobladder is achieved and completed mainly by abdominal straining rather than by the spontaneous contraction of the gastrointestinal segment, as evidenced by cystometric studies. The stomach generates high pressures during its peristaltic contractions but this could be a disadvantage during the early postoperative period particularly in the females, as urinary incontinence may result. In the majority of patients, micturition takes place every 2 to 3 hours with full urinary continence during the waking hours. However, in patients after radical total cystectomy, incontinence of urine during deep sleep is inevitable. No differences of voiding pattern, bladder capacity and residual urine volume are noted when either the colon, ileum or stomach is used for cystoplasty.

The effects of atrial fibrillation were studied in 12 healthy unanesthetized dogs, 9 to 49 days after surgical implantation of transducers for measurement of aortic flow and left ventricular diameter. Atrial fibrillation and pacing at comparable ventricular rates were induced by electrical stimulation of the right atrial appendage, and their effects were compared with observations made during sinus rhythm in each dog. At rest, cardiac output and mean arterial pressure were not significantly different during sinus rhythm, atrial fibrillation, and atrial pacing. After beta-adrenergic blockade with propranolol, cardiac output during fibrillation was significantly less than that during pacing at comparable ventricular rates. Arterial pressure was not detectably altered. During moderately severe treadmill exercise by six dogs, cardiac output fell significantly upon induction of fibrillation. After pentobarbital anesthesia fibrillation caused decrements in cardiac output and arterial pressure that were accentuated after thoracotomy.These observations suggest the existence of compensatory mechanisms that maintain an essentially constant cardiac output when atrial fibrillation is induced in healthy unanesthetized dogs at rest. These mechanisms appear to fail during moderately severe exercise, beta-adrenergic blockade, and pentobarbital anesthesia.