Children with stones now account for 1 in 685 pediatric hospitalizations in the United States. Surprisingly more than half of the patients are younger than 13 years at hospitalization. Similar to findings in adults, white race and occurrence in late summer months increase the risk of stone hospitalization. However, male gender and geographic location in the Southeast are not risk factors, demonstrating the unique aspects of pediatric stone hospitalization.

THE frequent occurrence of decarboxylation in the degradative and synthetical procedures of organic chemistry and during the enzymic reactions of biochemistry, and the use of the decarboxylation reaction to illustrate the fundamentals of reaction kinetics in solution, are a sufficient indication of its importance. Organic chemists early recognised the value of decarboxylation and applied it as a standard method for the degradation and synthesis of molecules. Simultaneously physical chemists studied the rates of decarboxylation of organic acids in solution and used the results in the formulation of the theory of unimolecular reactions. Then came the combination of organic and physical methods with the object of elucidating the mechanism of thermal decarboxylation. This phase of the development of our knowledge of decarboxylation is outlined in this Review, but it is not out of place to notice that the success achieved in this direction is aiding the investigation of the mechanism of enzymic decarboxylation reactions.Recent work has shown that decarboxylation can occur either by a unimolecular or by a bimolecular mechanism. Many years ago kinetic investigations made known the unimolecular decomposition of acid molecules. Within the past twenty years evidence has accumulated to substantiate this mechanism, and careful kinetic work has proved that many organic acids are decarboxylated in the form of their anions : R-COi--+ R-+ CO, However, some organic acids are known to be decarboxylated more readily as free acids.as a unimolecular decomposition of the acid in a zwitterionic form :This effect has been interpreted 1* 2, R*CO,H + H+R-CO,--+ HR + CO, for example, The idea that some decarboxylations take place in a bimolecular manner was first suggested in 1948 : *

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SummaryThe role of amputation in limb salvage is often poorly defined because the surgeon and the patient often attempt to save all limbs at all costs. The difficulty lies in selecting limb salvage versus early amputation. For the sedentary patient, a poorly functional salvaged limb can provide him/her with a higher quality of life than he/she would have with an amputation. For the active patient, early major amputation may offer the best functional outcome. Our experience with diabetic limb salvage over the last 20 years was retrospectively reviewed and compared with the existing literature in an attempt to better understand the role of amputation versus limb salvage in patients with diabetes. In the process, surgical techniques that we believe optimize foot and leg amputations were reviewed. Utilizing a team approach, limb salvage can yield a 64% ambulation rate and an 80% 2-year survival rate. Below-knee amputation led to a similar ambulatory rate, but the 2-year survival in these patients was 52%. With more severe rear-foot ulcers and osteomyelitis, the ambulatory rate declined with each co-morbity. However, those whose foot was saved had a higher chance of walking than those who underwent amputation. Function and quality of life are the outcomes of interest and may be maximized through either limb salvage or amputation. Our job as physicians is to match the correct solution to the patients' lifestyle and their medical, physical and psychological conditions so they can achieve their desired level of activity as quickly as possible. Level of evidence: IV.

The influence of the relative concentrations of amino acids in culture media on the growth of microorganisms was first brought to the attention of microbiologists by Gladstone (1939). He observed that isoleucine, valine, or leucine added singly to a synthetic medium inhibited the growth of the anthrax bacillus whereas a mixture of the three stimulated growth. Although Gladstone was unable at that time to explain the nature of the imbalance, he did suggest two possibilities. The more obvious possibility was

Microvascular anastomotic coupling devices create effective venous anastomoses in lower extremity microvascular reconstruction. Thus, it presents an important tool in the armamentarium for lower extremity microsurgical reconstruction.

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