Short-term suppression of plasma free fatty acids fails to improve insulin sensitivity when intramyocellular lipid is elevated.

AIMS: Metabolic responses to manipulation of the plasma free fatty acid (FFA) concentration were assessed in six healthy men via cross-over design to determine whether FFAs independently influence insulin sensitivity. METHODS: Intramyocellular lipid (IMCL) was measured by proton magnetic resonance spectroscopy and insulin sensitivity via frequently sampled intravenous glucose tolerance test (IVGTT) after 67 h of two identical low carbohydrate/high fat (LC) diets which were used to elevate IMCL and plasma FFAs. To uncouple the influence of FFAs and IMCL on insulin sensitivity, FFAs were suppressed 30 min prior to and during IVGTT in one treatment [LC + nicotinic acid (NA)] by NA ingestion. RESULTS: Vastus lateralis IMCL was significantly elevated in LC (13.3 +/- 1.1 x 10(-3)) and LC + NA (13.5 +/- 1.1 x 10(-3)) (P < 0.01 for both), but was not different between conditions (P > 0.05). Plasma FFAs were raised in LC (0.79 +/- 0.08 mmol/l) and LC + NA (0.80 +/- 0.11 mmol/l) (P < 0.01 for both) and were significantly reduced by NA ingestion prior to (0.36 +/- 0.05 mmol/l, P < 0.01) and during IVGTT (P < 0.05) in LC + NA. Despite marked differences in plasma FFA availability, insulin sensitivity and glucose tolerance were not different between LC and LC + NA (P > 0.05 for both). CONCLUSIONS: Plasma FFAs appear to exert no immediate effect on insulin sensitivity/glucose tolerance independent of their action on intracellular lipid moieties. Further research is required to elucidate the duration of FFA suppression required to restore insulin sensitivity following lipid-induced insulin resistance.     

Transduodenal Sphincteroplasty and Transampullary Septectomy for Papillary Stenosis

Twenty patients received transduodenal sphincteroplasty and transampullary septectomy between 1987 and 1993. Seven patients had post-cholecystectomy pain which was much improved or abolished in 5 of 7 patients at a mean follow-up of 4 years and 5 months. Four of five patients with chronic pancreatitis were improved at 3 years and 2 months. Three of five patients with recurrent acute pancreatitis were improved at 4 years and 5 months. One of three patients with chronic abdominal pain of hepatobiliary origin was improved at 3 years. Transduodenal sphincteroplasty and transampullary septectomy can relieve pain in patients with post-cholecystectomy pain, recurrent acute pancreatitis, chronic pancreatitis, and chronic abdominal pain of hepatobiliary origin, presumably by improving drainage of the obstructed ducts.     

Comparison of plasma extraction techniques in preparation of samples for endotoxin testing by the Limulus amoebocyte lysate test.

Due to the presence of inhibitory and possible mimicking substances in plasma difficulties have occurred in the use of the Limulus amoebocyte lysate test. Currently, there are a variety of extraction techniques discussed in the literature which are used to remove these interfering substances, but there is little information comparing these techniques. Five such procedures were compared in their ability to provide an extracted plasma sample in which low levels of endotoxin could be detected by the Limulus amoebocyte lysate test. Results indicated that some procedures adversely affected endotoxin detection. The dilution + heating extraction method was found to be as effective as the widely used chloroform extraction method. Comparison of Limulus amoebocyte lysate test results from healthy human plasma samples extracted by these two methods indicated that lysate type and not extraction procedure was associated with previously reported questionable positive tests. Thus, ambiguities associated with Limulus amoebocyte lysate tests of plasma samples may be due not only to extraction method but also the lysate type employed.     

Nongenetic Determinants of Human Serum Esterases

A panel of 1151 unselected individuals was screened by starch gel electrophoresis for serum esterase variants. Two types of variants were observed which were shown by family studies not to be genetically determined. No consistent disease process was correlated with the occurrence of these variants. Suggestive evidence has been obtained to support the hypothesis that these variant proteins were produced by the action of exogenous neuraminidase on the individuals' normal C, esterases. A third type of variant enzyme was observed in 1 patient. This enzyme was shown to be a substantially larger molecule than the C, esterase and it is suggested that this protein may be a polymer of the C, esterase.     

Nucleolar organising regions in cervical intraepithelial neoplasia.

The variations in the numbers of nucleolar organising regions (NORs) among different grades of cervical intraepithelial neoplasia (CIN) were investigated using a silver staining technique. Twenty four biopsy specimens were studied (six normal and six of each of the three grades of CIN) by staining paraffin wax sections using a silver (AgNOR) method that stains the NORS as multiple black dots within nuclei (AgNORs). The number of AgNORs in the nuclei of cells in the basal half of the squamous epithelium was counted, and the average number of AgNORs in each cell calculated for each specimen (the AgNOR count). There was no difference in the number of AgNORs in the squamous epithelium of normal biopsy specimens and those showing CIN1 and CIN2, but there was a small but significant increase in the CIN3 group.     

The development of serum proteins and humoral immunity in opossum `embryos'

The development of serum proteins, immunoglobulins and the immune response was studied in opossum `embryos'. Serum proteins gradually increased from birth to 80 days of age when adult values were obtained. γM immunoglobulins were found at all stages of development but γG immunoglobulins were less regularly present. Those `embryos' which were 5 days or older at the time of immunization had an immune response to bacteriophage f2 and `embryos' 15 days or older responded to a hapten determinant, DNP. γM antibodies were most prominent but γG antibodies could also be detected in the immune response of opossum `embryos'.