Pharmacokinetics in renal failure

A knowledge of pharmacokinetic principles is essential to understand dosage modification for drugs used in patients in renal failure. Dosage modification is indicated either where drugs have a low therapeutic index, or where renal mechanisms play a major role in drug elimination. Drug renal clearance can be indexed to creatinine clearance in order to gauge the degree of drug elimination impairment. Two schemes of dosage modification have been proposed; dosage interval extension or dosage size reduction. In addition to effects on drug elimination, renal failure may also alter drug absorption, distribution, protein binding and metabolism. Dialysis regimens, by eliminating drugs to a greater or lesser degree, have implications for drug therapy.     

Acid mucopolysaccharides in gingivities and periodontitis

Human Gingival Tissues was clinically classified as normal or periodontally involved. Acid mucopolysaccharides were extracted from this tissue. The measurable acid mucopolysaccharides extracted were chondroitin sulfules A and C. Concentration of chondroitin sulfate was lower in the tissue classified as periodontally involved when compared to the normal tissue.     

Train-of-Four: To Use or Not to Use

A pattern of nerve stimulation called train-of-four (TOF) is frequently used to monitor therapy with nondepolarizing neuromuscular blocking agents in patients treated in intensive care units. Based on our experience with TOF monitoring in several critically ill patients, we believe its application as an indicator of neuromuscular blockade may be problematic in this setting.     

Microalbuminuria in non-insulin-dependent diabetes: its prevalence in Indian compared with Europid patients

Non-insulin-dependent diabetes mellitus is strikingly common in British Indians, but their susceptibility to diabetic complications is unknown. The ratio of albumin to creatinine concentrations was measured in samples of the first urine voided in the morning in 154 Indian and 82 Europid patients with non-insulin-dependent diabetes and in a control group of 129 non-diabetic Indians. The ratio was significantly higher in the Indian patients than in the Europid patients and the Indian controls. There were no significant correlations between the logarithm of the albumin: creatinine ratio and age, known duration of diabetes, haemoglobin A1 concentration, or body mass index within either diabetic group. Hypertension and raised albumin:creatinine ratio were significantly associated, and significant correlations were seen between the logarithm of the albumin:creatinine ratio and systolic and diastolic blood pressures in the Indian but not the Europid diabetics. Because of the high prevalence of diabetes at a relatively early age in Indians, nephropathy may emerge as an important clinical problem.     

Pituitary imaging using a labelled somatostatin analogue in acromegaly

OBJECTIVE: A number of neoplasms are known to express somatostatin receptors, and the use of somatostatin receptor imaging in their localization has recently been described. We have looked at the use of an 123I-labelled Tyr3-octreotide analogue of somatostatin in the visualization and functional characterization of growth hormone-secreting pituitary adenomas. PATIENTS: Fifteen patients with biochemically-proven acromegaly were scanned using this agent. In eight of these we also assessed acute GH responses to octreotide in order to correlate these responses with tumour uptake characteristics. MEASURES: Planar and single-photon-emission computerized tomographic (SPECT) images of the head were obtained using a gamma-camera at 10 minutes, and 4 and 24 hours, after injection of the radiopharmaceutical. Blood for serum GH was sampled for 12 hours after administration of a single dose of 100 micrograms octreotide. RESULTS: Twelve of the acromegalic subjects showed significant uptake of the radiopharmaceutical in the pituitary fossa. Of the eight patients in whom we assessed acute GH responses, five demonstrated a significant fall in GH in response to octreotide. These subjects also showed positive uptake in the pituitary on scanning. The three patients who had no fall in GH had no uptake on scanning. CONCLUSIONS: Uptake of 123I-labelled Tyr3-octreotide in the pituitary fossa appears to correlate closely with the presence of a therapeutic response to octreotide.