Identification of substance P metabolites using a combination of reversed-phase high-performance liquid chromatography and capillary electrophoresis

Gradient elution reversed-phase high-performance liquid chromatographic and capillary electrophoretic separations were optimised to separate substance P (SP) and twelve of its fragments. The methods were applied to a study of the in vivo metabolism of substance P in the rat after intrastriatal injection of the peptide (10 nmol). SP and significant amounts of its N-terminal fragments, SP(1-7) and SP(1-4), were detected but no major C-terminal fragments could be identified. At the concentration studied, the metabolism of SP was shown to follow zero order elimination kinetics with a rate of decay of 0.2 nmol/min. As we have shown that SP(1-4) and SP(1-7) can be produced in vivo in the striatum in relatively large amounts, it is conceivable that these fragments contribute to the overall pharmacological pattern of activity of the parent peptide.

Cloning and functional characterisation of a peptide transporter expressed in the scutellum of barley grain during the early stages of germination

A peptide transport gene (HvPTR1) expressed in the scutella of germinating barley grain has been cloned by an RT-PCR approach. Sequence analysis of the full length cDNA (2260 bp) revealed an open reading frame encoding a 579 amino acid protein of predicted molecular mass 63 kDa, which displayed 58% identity to the Arabidopsis thaliana peptide transporter AtPTR2-B. Expression of HvPTR1 in Xenopus laevis oocytes conferred a 48-fold increase in alanyl-[14C]phenylalanine uptake relative to water injected oocytes, confirming the function of HvPTR1 as a peptide transporter. HvPTR1 expression was detectable only in the scutellum of the germinating barley grain, with no transcript found in roots, shoots or the embryo axis. Transcript levels increased rapidly from 6 to 24 h imbibition, correlating with the development of peptide transport activity in the barley scutellum. Peptide transport provides a significant source of organic nitrogen to the barley embryo for use in germination and growth processes associated with the early stages of seedling development. The temporal and spatial pattern of HvPTR1 expression is consistent with a central role for HvPTR1 in the transport of peptides in the germinating barley grain.

Choosing an electroconvulsive therapy device

The selection of an electroconvulsive therapy (ECT) device from the more than 10 American-made models can be a difficult endeavor. This article is meant to be a single source of basic descriptions of these ECT devices. The information provided will allow the ECT clinician to be aware of the important issues involved in the selection of an ECT device and to become familiar with the basic features of each model.

Evidence for less improvement in depression in patients taking benzodiazepines during unilateral ECT

Among 48 patients with diagnoses of depression according to DSM-III, there was a significant relation between therapeutic failure of unilateral ECT, as measured by scores on the Hamilton Rating Scale for Depression, and the concomitant use of a benzodiazepine. Of the 34 patients who showed a good therapeutic response to unilateral ECT, those taking benzodiazepines had smaller changes in their Hamilton depression ratings from before treatment to after treatment and were more symptomatic at the end of the course of ECT. Thus, when patients take benzodiazepines during a course of unilateral ECT, the maximum therapeutic response may be compromised.

A randomised controlled trial of the effect of low fat diet advice on dietary response in insulin independent diabetic women

Type 2 (insulin independent) diabetic women were randomly allocated to receive advice for low fat diets or low carbohydrate diets. By 24 h weighted dietary intakes before and after a mean interval of six months, patients in the low fat group had reduced their fat intake from 41% to 31% of total energy, while carbohydrate percentage of total energy intake increased from 38% to 46%. Percentage energy intake from fat and carbohydrate in the control group remained unchanged. Body weight fell in both groups especially for patients in the low fat group who were obese (weight/height2 greater than or equal to 28 kg/m2). Mean plasma glucose, HbA1, and triglycerides were unchanged. Mean plasma total cholesterol fell significantly in the low fat group compared with the controls (p less than 0.001), but there was no significant difference in the small reduction of high density lipoprotein cholesterol observed in both groups. Thus, adherence to low fat diets occurred without deterioration of diabetes and with benefit for weight and total cholesterol.