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Table 1. Effects of amino acids upon the time required for abscission of unfertilized ovaries of two varieties of tobacco. The figures show average time in hours from anthesis to completion of abscission. Lizard's Tail Little Turkish 0.01M 0.1M 0.01M 0.1M Methionine Control (water) 99 93 176 165 Table 1. Effects of amino acids upon the time required for abscission of unfertilized ovaries of two varieties of tobacco. The figures show average time in hours from anthesis to completion of abscission. Lizard's Tail Little Turkish 0.01M 0.1M 0.01M 0.1M Methionine Control (water) 99 93 176 165others is uncertain at present, but it is generally agreed that indoleacetic acid plays a major role in the control. The dissolution of the middle lamella of the cell wall during abscission was described first by Lee (3). Facey (4), through microchemical tests, characterized the dissolution as a change of calcium pectate into pectic acid which, in turn, is changed to water-soluble pectin. Recently Cormack (5) has emphasized the calcium pectate character of the cementing layer between cells. Ordin, Cleland, and Bonner (6) have reported that the methyl carbon atom of labeled methionine is rapidly incorporated into the pectic materials of cell walls of Avena coleoptile sections, and Byerrum and Sato (7) have also reported the incorporation of the methyl group of methionine in pectin isolated from radish plants. These observations suggest that methylation of the carboxyl groups of adjacent pectin molecules may be involved in the splitting of calcium bridges leading to abscission and that the amino acid methionine may serve as a methyl group donor. Experimental evidence indicates that an amino acid factor does, in part, control abscission.Two varieties of Nicotiana tabacum, namely Lizard's Tail and Little Turkish, were grown under uniform greenhouse conditions and used as experimental plants. Various aqueous solutions of L-amino acids (DL-methionine, DL-leucine, DL-valine), after being adjusted to pH 6.0, were injected directly into the unfertilized ovaries of flowers at the time of anthesis by means of glass tubing drawn to a fine point. In 24 hours, 0.15 to 0.2 ml of the solution were 10 JANUARY 1958

W rITH the contemporary development of surgical methods of treating the symptoms of painful, psychiatric, and basal ganglion disorders, the neurosurgcon is frequently called upon to produce a focal destructive lesion in the nervous system. The universal and obvious objective is to create a localized lesion in the desired area with no damage to adjacent or intervening tissues. Recorded experiences of neurosurgeons attest to the fact that this ideal has not yet been attained. Paraparesis and bladder dysfunction following anterolateral chordotomy, vegetation following prefrontal lobotomy, and hemiplegia following surgical treatment of basal ganglion disorders are examples of damage to adjacent tissues known to all neurosurgeons. Damage to blood vessels (including those within the site of the lesion) at time of operation may increase the operative morbidity and render it impossible to evaluate the effect of a focal ablation. Stereotaxically placed electrocoagulative lesions have frequently resulted in death from hemorrhage.As the result of animal experimentation 1-4,6 we believe that the use of ultrasound in making human focal destructive lesions will overcome some of these objections. A focussed beam of ultrasound can be used to produce selective, accurately localized lesions in the central nervous system which are quantitatively reproducible from one animal to another. Discrete lesions can be produced without destruction of blood vessels. A lesion in the depths of the brain can be effected without disturbance of intervening tissue. Accurate localization is accomplished by focussing a fine beam of ultrasound in the region to be treated. The nature of the destruction depends upon the intensity and duration of the exposure.The term "ultrasound" refers to sounds whose frequency (pitch) is above the range of human audibility (15,000 to ~0,000 cycles per second). M:ost of the work up to the present time has been accomplished at a frequency of one * Partially supported by Contract Nonr 336(00), NR 119-075 with the Physiology Branch of the Office

Of one hundred and forty-nine patients (101 male and 48 female) 4-67 years of age, 117 were alcoholics and underwent pancreatectomy because of episodic or continuous abdominal pain or complications or chronic pancreatitis. Nineteen patients underwent pancreaticoduodenectomy, seventy-seven 80-95% distal resection, anf fifty-three 40-80% distal pancreatic resection. There were 3 operative death and 30 late deaths 6 months to 11 years post pancreatectomy. Twenty-one patients were lost to followup, 1 to 11 years post pancreatectomy. Ninety-five patients are known to be alive, 4 of whom are institutionalized. Indications for pancreatectomy in addition to abdominal pain include recurrent or multiple pseudocysts, failure to relieve pain after decompression of a pseudocyst, pseudoaneurysm of the visceral arteries associated with a pseudocyst, recurrent attacks of pancreatitis unrelived by non-resective operations, duodenal stenosis and left side portal hypertension. The choice between pancreaticoduodenectomy or distal resection of 40-80% or 80-95% of the pancreas should be based on the principle site of inflammation whether proximal or distal in the gland, the size of the common bile duct, the ability to rule out carcinoma, and the anticipated deficits in exocrine and endocrine function. The risk of diabetes is very significant after 80-95% distal resection and of steatorrhea after pancreaticoduodenectomy. When the disease process can be encompassed by 40-80% distal pancreatectomy this is the procedure of choice.

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