Universal vs. risk factor-based screening for gestational diabetes mellitus: detection rates, gestation at diagnosis and outcome

AIMS

Gestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcome. Screening for GDM is therefore recommended but the best screening method remains controversial. This prospective, randomized study compared a risk factor-based screening programme with a universally based one.

METHODS

Subjects were randomized at booking to one of two groups: the risk factor group had a 3-h 100-g oral glucose tolerance test (OGTT) at 32 weeks if any risk factor for GDM was present; the universal group had a 50-g glucose challenge test performed and if their plasma glucose at 1 h was > or = 7.8 mmol/l, a formal 3-h 100-g OGTT was then performed.

RESULTS

Universal screening detected a prevalence of GDM of 2.7%, significantly more than the 1.45% detected in the risk factor screened group (P<0.03). Universal screening facilitated earlier diagnosis than risk factor screening - mean gestation 30 +/- 2.6 weeks vs. 33 +/- 3.7 weeks (P<0.05). A higher rate of spontaneous vaginal delivery at term, and lower rates of macrosomia, Caesarean section, prematurity, pre-eclampsia and admission to neonatal intensive care unit were observed in the universally screened, early diagnosis group.

CONCLUSIONS

Universal screening for GDM is superior to risk factor based screening-detecting more cases, facilitating early diagnosis and is associated with improved pregnancy outcome.

Free fatty acid-induced insulin resistance is associated with activation of protein kinase C theta and alterations in the insulin signaling cascade

To examine the mechanism by which free fatty acids (FFAs) induce insulin resistance in vivo, awake chronically catheterized rats underwent a hyperinsulinemic-euglycemic clamp with or without a 5-h preinfusion of lipid/heparin to raise plasma FFA concentrations. Increased plasma FFAs resulted in insulin resistance as reflected by a approximately 35% reduction in the glucose infusion rate (P < 0.05 vs. control). The insulin resistance was associated with a 40-50% reduction in 13C nuclear magnetic resonance (NMR)-determined rates of muscle glycogen synthesis (P < 0.01 vs. control) and muscle glucose oxidation (P < 0.01 vs. control), which in turn could be attributed to a approximately 25% reduction in glucose transport activity as assessed by 2-[1,2-3H]deoxyglucose uptake in vivo (P < 0.05 vs. control). This lipid-induced decrease in insulin-stimulated muscle glucose metabolism was associated with 1) a approximately 50% reduction in insulin-stimulated insulin receptor substrate (IRS)-1-associated phosphatidylinositol (PI) 3-kinase activity (P < 0.05 vs. control), 2) a blunting in insulin-stimulated IRS-1 tyrosine phosphorylation (P < 0.05, lipid-infused versus glycerol-infused), and 3) a four-fold increase in membrane-bound, or active, protein kinase C (PKC) theta (P < 0.05 vs. control). We conclude that acute elevations of plasma FFA levels for 5 h induce skeletal muscle insulin resistance in vivo via a reduction in insulin-stimulated muscle glycogen synthesis and glucose oxidation that can be attributed to reduced glucose transport activity. These changes are associated with abnormalities in the insulin signaling cascade and may be mediated by FFA activation of PKC theta.

Effects of free fatty acids on glucose transport and IRS-1-associated phosphatidylinositol 3-kinase activity

To examine the mechanism by which free fatty acids (FFA) induce insulin resistance in human skeletal muscle, glycogen, glucose-6-phosphate, and intracellular glucose concentrations were measured using carbon-13 and phosphorous-31 nuclear magnetic resonance spectroscopy in seven healthy subjects before and after a hyperinsulinemic-euglycemic clamp following a five-hour infusion of either lipid/heparin or glycerol/heparin. IRS-1-associated phosphatidylinositol 3-kinase (PI 3-kinase) activity was also measured in muscle biopsy samples obtained from seven additional subjects before and after an identical protocol. Rates of insulin stimulated whole-body glucose uptake. Glucose oxidation and muscle glycogen synthesis were 50%-60% lower following the lipid infusion compared with the glycerol infusion and were associated with a approximately 90% decrease in the increment in intramuscular glucose-6-phosphate concentration, implying diminished glucose transport or phosphorylation activity. To distinguish between these two possibilities, intracellular glucose concentration was measured and found to be significantly lower in the lipid infusion studies, implying that glucose transport is the rate-controlling step. Insulin stimulation, during the glycerol infusion, resulted in a fourfold increase in PI 3-kinase activity over basal that was abolished during the lipid infusion. Taken together, these data suggest that increased concentrations of plasma FFA induce insulin resistance in humans through inhibition of glucose transport activity; this may be a consequence of decreased IRS-1-associated PI 3-kinase activity.

Dobutamine stress echocardiography: false positive scans in proteinuric patients with type 1 diabetes mellitus at high risk of ischaemic heart disease

Patients with Type 1 diabetes mellitus have an increased risk of ischaemic heart disease (IHD). When diabetes is complicated by nephropathy this risk is further increased and asymptomatic IHD is common. New techniques for non-invasive cardiac evaluation are now available and one of these, Dobutamine Stress Echocardiography (DSE), was studied in subjects with Type 1 DM and nephropathy who had no evidence of IHD. DSE was performed on 18 subjects (13 male, 5 female; mean age 37.8 +/- 3.4 years), diabetes duration 23.7 +/- 1.2 years and nephropathy diagnosed for 10.9 +/- 1.3 years. There were 7 (38%) positive scans-suggesting asymptomatic IHD; 16.7% of subjects studied had a significant arrhythmia. Coronary angiography was performed in 6 of the 7 subjects with positive DSEs and was positive in only 2. These results suggest that DSE has a high rate of false positive results in Type 1 DM patients suffering from nephropathy and may limit its usefulness in these subjects.

Methanogenic population dynamics during start-up of anaerobic digesters treating municipal solid waste and biosolids

An aggressive start-up strategy was used to initiate codigestion in two anaerobic, continuously mixed bench-top reactors at mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The digesters were inoculated with mesophilic anaerobic sewage sludge and cattle manure and were fed a mixture of simulated municipal solid waste and biosolids in proportions that reflect U.S. production rates. The design organic loading rate was 3.1 kg volatile solids/m3/day and the retention time was 20 days. Ribosomal RNA-targeted oligonucleotide probes were used to determine the methanogenic community structure in the inocula and the digesters. Chemical analyses were performed to evaluate digester performance. The aggressive start-up strategy was successful for the thermophilic reactor, despite the use of a mesophilic inoculum. After a short start-up period (20 days), stable performance was observed with high gas production rates (1.52 m3/m3/day), high levels of methane in the biogas (59%), and substantial volatile solids (54%) and cellulose (58%) removals. In contrast, the mesophilic digester did not respond favorably to the start-up method. The concentrations of volatile fatty acids increased dramatically and pH control was difficult. After several weeks of operation, the mesophilic digester became more stable, but propionate levels remained very high. Methanogenic population dynamics correlated well with performance measures. Large fluctuations were observed in methanogenic population levels during the start-up period as volatile fatty acids accumulated and were subsequently consumed. Methanosaeta species were the most abundant methanogens in the inoculum, but their levels decreased rapidly as acetate built up. The increase in acetate levels was paralleled by an increase in Methanosarcina species abundance (up to 11.6 and 4.8% of total ribosomal RNA consisted of Methanosarcina species ribosomal RNA in mesophilic and thermophilic digesters, respectively). Methanobacteriaceae were the most abundant hydrogenotrophic methanogens in both digesters, but their levels were higher in the thermophilic digester.

Ganglioside composition of a mouse brain tumor grown in the severe combined immunodeficiency (SCID) mouse

The content and composition of gangliosides were examined in an experimental mouse brain tumor, EPEN, that was grown subcutaneously in the flank of the syngeneic C57BL/6J (B6) host and in the B6 severe combined immunodeficiency (SCID) host. SCID mice lack functional T- and B-lymphocytes, but have a normal complement of macrophages. The content and distribution of the brain tumor gangliosides were similar whether the tumor was grown in the immunocompetent B6 host or in the B6-SCID host. N-acetylneuraminic acid- (NeuAc) containing GM3 was the major ganglioside in the subcutaneous tumors and in the cultured EPEN cells. Significant amounts of N-glycolylneuraminic acid- (NeuGc) containing gangliosides were found in the tumor grown in both mouse hosts. NeuGc-containing gangliosides are not expressed in normal mouse brain, but are present in macrophages and serum. An extremely complex pattern of minor gangliosides was found in the subcutaneous tumors on two-dimensional, high-performance thin-layer chromatograms. Most of the minor gangliosides comigrated with those found in mouse macrophages. The results show that the absence of functional T- and B-lymphocytes does not markedly affect brain tumor ganglioside composition and suggest that NeuGc-containing gangliosides in the EPEN can be derived from tumor infiltrating host cells (mostly macrophages) and from the extracellular milieu (serum).

Efficacy of combination therapy in non-insulin dependent diabetes mellitus

Secondary failure of oral hypoglycaemic agents raises the dilemma of whether to institute therapy with insulin alone, or in combination. We reviewed our experience of combination therapy following secondary failure of oral hypoglycaemic therapy. Seventeen subjects were receiving combination therapy for 6 months or more. Such treatment was associated with a significant fall in HbA1C--from 10.7 +/- 0.38 per cent to 8.3 +/- 0.35 per cent (p < 0.01) after 6 months and remained significantly reduced at 12 months (8.7 +/- 0.34 per cent (p < 0.01)). Mean body weight, systolic and diastolic blood pressure were unchanged during treatment with adjuvant insulin therapy. Insulin therapy is a useful adjunct in the daily management of subjects with NIDDM who experience secondary failure of oral hypoglycaemic agents.

Autoantibodies to oxidized low density lipoprotein: the relationship to low density lipoprotein fatty acid composition in diabetes

Autoantibodies to oxidized low density lipoprotein have been shown to be an independent predictor of the progression of carotid atherosclerosis. This study examines the relationship between low density lipoprotein fatty acid composition and autoantibodies to both malondialdehyde-modified and copper-oxidized low density lipoprotein in non-diabetic patients with (n = 17), and without (n = 18), definite evidence of previous myocardial infarction. The third group were non-insulin-dependent diabetic patients with no evidence of atherosclerosis (n = 15) and the fourth group were patients with non-insulin-dependent diabetes (n = 17) who had definite evidence of previous myocardial infarction. Fatty acids were measured by gas-liquid chromatography. Antibodies to malondialdehyde-modified low density lipoprotein and copper-oxidized low density lipoprotein were determined by an ELISA method. Autoantibodies to copper-oxidized low density lipoprotein were significantly higher in the non-diabetic patients with heart disease when compared to any other group (p < 0.05). Autoantibodies to malondialdehyde-modified low density lipoprotein were significantly higher in the non-diabetic subjects with heart disease and in both diabetic groups compared to non-diabetic subjects without coronary heart disease (p < 0.05). Linoleic acid (%) in low density lipoprotein did not differ between groups groups but arachidonic acid (%) was significantly lower in both diabetic and non-diabetic patients with coronary heart disease (p < 0.05). The diabetic patients with low antibodies had 39.6 +/- 2.2% polyunsaturated fatty acids in their low density lipoprotein while diabetic patients with high antibodies had 46.7 +/- 1.2% polyunsaturates in their low density lipoprotein (p < 0.01). This study confirms the association between antibodies to oxidized low density lipoprotein and coronary heart disease and shows raised low density lipoprotein antibody levels in diabetic patients with and without demonstrable atherosclerosis. In the diabetic patients, those with high antibody levels had high polyunsaturated fatty acid levels in their LDL suggesting a possible role for dietary intervention.

Non-insulin-dependent diabetes mellitus: dietary monounsaturated fatty acids and low-density lipoprotein composition and function

Alterations in low-density lipoprotein (LDL) composition in diabetes affect its function with respect to control of de novo cholesterol synthesis. We examined the effect of 4 weeks of an oleic-acid-rich diet on LDL composition and function in eight Type 2 diabetic and eight non-diabetic control subjects. LDL (density 1.019-1.063 g/l) was isolated by sequential ultracentrifugation. LDL composition was measured and LDL fatty acids were determined by gas liquid chromatography. Cholesterol synthesis was measured by [14C]-acetate incorporation into the freshly isolated mononuclear leucocytes. Fasting blood glucose fell from 9.3 +/- 2.0 to 8.2 +/- 1.2 mmol/l (p < 0.05) and fasting serum insulin increased from 8.3 +/- 2.8 to 10.4 +/- 5.0 mIU/l (p > 0.05) in the diabetic patients. LDL oleic acid increased in the diabetic patients from 18.8 +/- 1.8% to 22.5 +/- 1.9% (p < 0.01) and in the non-diabetic subjects from 19.9 +/- 1.8% to 23.3 +/- 2.8% (p < 0.01). The LDL-esterified to free cholesterol ratios of 3.0 +/- 0.6 and 2.7 +/- 0.2 for the diabetic and non-diabetic patients were similar, and decreased significantly (p < 0.01) to 2.4 +/- 0.5 and 2.2 +/- 0.4, respectively. Baseline [14C]-acetate incorporation was similar in the two groups, and decreased after diet from 437 +/- 239 to 249 +/- 144 ng/g cell protein (p < 0.05) in the diabetic patients. There was a negative correlation between the LDL-esterified to free cholesterol ratio and the ratio of oleic to linoleic acid in the LDL (r = -0.39, p < 0.05) and a negative correlation between fasting blood glucose and LDL oleic acid in the diabetic patients (r = -0.51, p < 0.05). Enrichment of LDL with oleic acid appears to improve its ability to regulate endogenous cholesterol synthesis in both control and diabetic subjects. In the diabetic population, the diet had a favourable effect on glycaemic control.

Skin resurfacing with the Ultrapulse carbon dioxide laser. Observations on 100 patients

BACKGROUND

The Ultrapulse carbon dioxide (CO2) laser has been shown to be a highly effective treatment for photodamaged skin including improvement of rhytides, precancerous and benign skin lesions, as well as superficial benign pigmented lesions.

OBJECTIVE

We describe our experiences using the Ultapulse CO2 laser in treating 100 patients with different severities of photodamaged skin.

METHODS

All patients had moderately or severely photodamaged skin and were selected for treatment with the Ultrapulse CO2 laser to evaluate the efficacy and toxicity of this treatment. The patients were placed on a pretreatment regimen for 2-6 weeks prior to receiving treatment with the Ultrapulse CO2 laser. Patients were evaluated for pre- and posttreatment severity of photodamage. In addition, skin surface replicas were obtained in selected patients and evaluated by computer image analysis technology.

RESULTS

At 1 month post-laser treatment, 68 patients received a moderate improvement, five patients achieved a marked improvement, and the remaining 27 patients showed minimal improvement. By 2 months post-laser treatment, 20 of the 27 patients who at 1 month showed only minimal improvement revealed a moderate to marked improvement from baseline. All the patients studied developed a transient erythema that lasted up to 6 weeks, and many of these patients showed a transient hyperpigmentation that persisted for up to 4 months.

CONCLUSION

The Ultrapulse CO2 laser is confirmed as an effective treatment for skin resurfacing of photodamaged skin.

Laser resurfacing in pigmented skin

BACKGROUND

Laser skin resurfacing is a very promising new treatment for solar elastosis and acne scars. The Ultrapulse carbon dioxide (CO2) laser and the SilkTouch flashscanner allow precise depth control and char-free ablation. Earlier studies have been done mainly on Caucasian skin types I and II, but very little data were available on pigmented skin.

OBJECTIVE

The purpose of this study is to assess the efficacy and safety of laser skin resurfacing in skin types III and IV.

METHODS

Thirty Asian and Hispanic patients were treated for facial rhytides and acne scars. All patients were instructed to use tretinoin cream 0.05%, hydroquinone 5%, and desonide 0.1% cream nightly for 2-4 weeks prior to the laser treatment. The Ultrapulse 5000C CO2 laser with the Truespot 3-mm collimated handpiece at the setting of 250-450 mJ per pulse, or the Silk-Touch flashscanner at the setting of 5-7 W, 0.2-second pulse duration, and 4-mm (M) spot size, was used. Patients were evaluated clinically, and global response was assessed by both clinicians and patients.

RESULTS

The facial rhytides and acne scars improved 25-50% in all patients after one laser treatment. The most common side effects were persistent erythema that resolved on the average of 6 weeks. Hyperpigmentation occurred, but was reduced with regular use of tretinoin, hydroquinone, and desonide cream both pre- and postoperatively along with use of broad spectrum sunscreen after treatments.

CONCLUSION

Laser skin resurfacing can be used to treat facial rhytides and acne scars in skin phototypes III and IV. When proper pre- and postoperative management is implemented, the risk of dyspigmentation can be reduced.

Laser skin resurfacing. Pre- and posttreatment guidelines

BACKGROUND

Carbon dioxide laser skin resurfacing using either ultrapulsed lasers or scanning skin lasers has evolved as an effective method of treating photodamaged skin.

OBJECTIVE

The purpose of this paper is to describe appropriate pre- and posttreatment regimens to ensure the optimum response to laser therapy.

METHODS

We describe our experiences with 30 patients treated with laser skin resurfacing using different pre- and posttreatment regimens. Patients were evaluated by physicians as regards to their responses to and recovery from laser therapy. Some patients agreed to skin biopsy and cutaneous patch testing of topically applied agents.

RESULTS

Eighty percent of patients achieved good to excellent improvement. Sixty-five percent of patients undergoing laser skin resurfacing developed contact dermatitis to several topical agents. Patch testing was negative on normal skin for contact allergy, suggesting a primary irritant reaction in laser-treated skin. Post-laser hyperpigmentation and erythema were the most noted immediate and mid-term side effects to laser resurfacing. An optimum pretreatment regime includes topical retinoids, skin lightening agents, and, immediately pretreatment, oral anti-herpes simplex medication plus oral antibiotics. An optimum posttreatment regimen includes minimizing topical therapy with the use of dilute acetic acid facial soaks. In addition, oral anti-herpes simplex medications and broad spectrum antibiotics are continued for 7 days post-laser resurfacing.

CONCLUSION

Laser skin resurfacing is an evolving means of treating photodamaged skin. Carefully selected pre- and posttreatment regimens, ideally under dermatologic supervision, are required to obtain optimum results.

Characterization of microbial communities in anaerobic bioreactors using molecular probes

The microbial community structure of twenty-one single-phase and one two-phase full-scale anaerobic sewage sludge digesters was evaluated using oligonucleotide probes complementary to conserved tracts of the 16S rRNAs of phylogenetically defined groups of methanogens and sulfate-reducing bacteria. These probe results were interpreted in combination with results from traditional chemical analyses and metabolic activity assays. It was determined that methanogens in "healthy" mesophilic, single-phase sewage sludge digesters accounted for approximately 8-12% of the total community and that Methanosarcinales and Methanomicrobiales constituted the majority of the total methanogen population. Methanobacteriales and Methanococcales played a relatively minor role in the digesters. Phylogenetic groups of mesophilic, Gram-negative sulfate-reducing bacteria were consistently present at significant levels: Desulfovibrio and Desulfobulbus spp. were the dominant sulfate-reducing populations, Desulfobacter and Desulfobacterium spp. were present at lower levels, and Desulfosarcina, Desulfococcus, and Desulfobotulus spp. were absent. Sulfate reduction by one or more of these populations played a significant role in all digesters evaluated in this study. In addition, sulfate-reducing bacteria played a role in favoring methanogenesis by providing their substrates. The analysis of the two-phase digester indicated that true phase separation was not accomplished: significant levels of active methanogens were present in the first phase. It was determined that the dominant populations in the second phase were different from those in the single-phase digesters.

Dietary choline requirement of juvenile hybrid striped bass

Two experiments were conducted to estimate the dietary choline requirement and to determine the effects of dietary choline on liver lipid deposition in juvenile hybrid striped bass (Monrone saxatilis x M. chrysops). Experimental diets contained 0.73 g total sulfur amino acids/100 g diet (0.47 g methionine + 0.26 g cyst(e)ine/100 g diet), thus meeting, but not exceeding, the requirement. Graded levels of choline bitartrate in Experiment 1 and choline chloride in Experiment 2 were added to the basal diet, resulting in eight dietary treatments in each experiment. Dietary treatments were 0, 250, 500, 1000, 2000, 4000, 6000 and 8000 mg choline/kg dry diet. Diets were fed for 12 and 10 wk in Experiments 1 and 2, respectively. Dietary choline concentrations significantly affected weight gain, feed efficiency, survival and total liver lipid concentrations in each experiment. Weight gain and feed efficiency were greatest in fish fed 500 mg choline/kg dry diet as choline bitartrate. Total liver lipid concentrations were variable but tended to be lowest in fish fed diets containing at least 2000 mg choline/kg diet. Survival was significantly lower in the group of fish fed 8000 mg choline/kg diet supplied by choline bitartrate. Weight gain and feed efficiency were greatest and total liver lipid concentration was lowest in groups of fish fed at least 500 mg choline/kg diet as choline chloride; survival was unaffected by dietary treatment. Therefore, choline chloride seems to be a better source of dietary choline than choline bitartrate and 500 mg choline/kg diet is adequate for maximum weight gain and prevention of increased liver lipid concentration in juvenile hybrid striped bass.

Dietary arginine requirement of juvenile hybrid striped bass

Two experiments were conducted to determine the dietary arginine requirement of juvenile hybrid striped bass (Morone saxatilis x M. chrysops); a third experiment evaluated the interaction of lysine and arginine. Diets in Experiments 1 and 2 were supplemented with graded concentrations of L-arginine-HCl, resulting in eight dietary treatments. Dietary arginine concentrations ranged from 1.0 to 2.4 g/100 g diet in Experiment 1 and from 0.6 to 2.0 g/100 g diet in Experiment 2. Weight gain was not affected by dietary treatments in Experiment 1. Feed efficiency was significantly affected by dietary arginine concentrations, and the data, when subjected to broken-line analysis, resulted in a requirement estimate of 1.53 +/- 0.20 g/100 g diet. Weight gain and feed efficiency were both significantly affected by dietary arginine concentrations in Experiment 2. Broken-line analyses of weight gain and feed efficiency data indicated the dietary arginine requirement to be 1.55 +/- 0.10 and 1.45 +/- 0.12 g/100 g diet, respectively. Diets in Experiment 3 contained lysine and arginine in ratios of 1:1, 1:1.5, 1:2 and 1:2.5 for the previously estimated requirements for both lysine:arginine and arginine:lysine. No differences were observed in weight gain or feed efficiency for fish fed various lysine:arginine ratios, but serum lysine was significantly different among treatment groups.

The dietary lysine requirement of juvenile hybrid striped bass

Two experiments were conducted to determine the dietary lysine requirement of juvenile hybrid striped bass (Morone saxatilis x M. chrysops). In both experiments the diets contained 35 g crude protein/100 g diet (10 g crude protein supplied by casein and gelatin and 25 g crude protein supplied by crystalline L-amino acids) and contained graded levels of L-lysine.HCl resulting in eight dietary treatments. Diets were fed to triplicate groups of fish and ranged in dietary lysine concentration from 1.2 to 2.6 g/100 g of the dry diet in Experiment 1 and from 0.8 to 2.2 g/100 g of the dry diet in Experiment 2. Weight gain and food efficiency data from Experiment 1 indicated the dietary lysine requirement to be between 1.2 and 1.4 g/100 g of the dry diet. Weight gain, food efficiency and serum lysine data from Experiment 2 confirmed the requirement to be between 1.2 and 1.4 g/100 g of the dry diet. Broken-line analysis of weight gain and food efficiency data from Experiment 2 indicated the dietary lysine requirement to be 1.4 +/- 0.2% of the dry diet, or 4.0 g/100 g of the dietary protein. Changes in the relative proportions of dietary lipid and carbohydrate between the two experiments, although maintaining similar gross energy levels, did not alter the lysine requirement estimate of juvenile hybrid striped bass.