Constipation in the elderly

Constipation affects as many as 26 percent of elderly men and 34 percent of elderly women and is a problem that has been related to diminished perception of quality of life. Constipation may be the sign of a serious problem such as a mass lesion, the manifestation of a systemic disorder such as hypothyroidism or a side effect of medications such as narcotic analgesics. The patient with constipation should be questioned about fluid and food intake, medications, supplements and homeopathic remedies. The physical examination may reveal local masses or thrombosed hemorrhoids, which may be contributing to the constipation. Visual inspection of the colon is useful when no obvious cause of constipation can be determined. Treatment should address the underlying abnormality. The chronic use of certain treatments, such as laxatives, should be avoided. First-line therapy should include bowel retraining, increased dietary fiber and fluid intake, and exercise when possible. Laxatives, stool softeners and nonabsorbable solutions may be needed in some patients with chronic constipation.     

Evaluation and treatment of head and neck venous vascular malformations

Congenital venous vascular malformations of the head and neck are low-flow, nonproliferative lesions that should be distinguished from hemangiomas. The characteristic history and clinical findings can establish the diagnosis. Direct percutaneous puncture and contrast injection at the time of treatment delineate the lesion and its drainage pattern. Treatment must be individualized according to lesion extent, patient tolerance and physician experience. Sclerotherapy with ethanol has proved to be a successful treatment modality for these lesions, as demonstrated in this study of 57 patients. Surgery is used for treatment of clinically significant residual disease. A multidisciplinary approach to evaluation and treatment is key to successful management.     

The synthesis of sialylated oligosaccharides using a CMP-Neu5Ac synthetase/sialyltransferase fusion

Large-scale enzymatic synthesis of oligosaccharides, which contain terminal N-acetyl-neuraminic acid residues requires large amounts of the sialyltransferase and the corresponding sugar-nucleotide synthetase, which is required for the synthesis of the sugar-nucleotide donor, CMP-Neu5Ac. Using genes cloned from Neisseria meningitidis, we constructed a fusion protein that has both CMP-Neu5Ac synthetase and alpha-2,3-sialyltransferase activities. The fusion protein was produced in high yields (over 1200 U/L, measured using an alpha-2,3-sialyltransferase assay) in Escherichia coli and functionally pure enzyme could be obtained using a simple protocol. In small-scale enzymatic syntheses, the fusion protein could sialylate various oligosaccharide acceptors (branched and linear) with N-acetyl-neuraminic acid as well as N-glycolyl- and N-propionyl-neuraminic acid in high conversion yield. The fusion protein was also used to produce alpha-2,3-sialyllactose at the 100 g scale using a sugar nucleotide cycle reaction, starting from lactose, sialic acid, phosphoenolpyruvate, and catalytic amounts of ATP and CMP.     

Effect of alcohol and carbon monoxide on the pH-activity relationship of erythrocytic delta-aminolevulinate dehydratase (ALA-D)

The effect of blood alcohol on the pH-activity profile of ALA-D in humans and rabbits has been measured. The shape of the pH-activity profile remains unchanged, although enzyme activities are significantly affected (up to 40%). In order for the blood lead assay using ALA-D to remain independent of the presence of alcohol, an alternative methodology, such as a ratio of activities at two pH values, and not a measurement at a single pH value should be used. The effect of carbon monoxide on the pH-activity profile of ALA-D, on the other hand, is minimal.