Determination of polycyclic aromatic hydrocarbons and their oxy-, nitro-, and hydroxy-oxidation products.

A sensitive method has been developed for the trace analysis of PAHs and their oxidation products (i.e., nitro-, oxy-, and hydroxy-PAHs) in air particulate matter (PM). Following PM extraction, PAHs, nitro-, oxy-, and hydroxy-PAHs were fractionated using solid phase extraction (SPE) based on their polarities. Gas chromatography-mass spectrometry (GC-MS) conditions were optimized, addressing injection (i.e., splitless time), negative-ion chemical ionization (NICI) parameters, i.e., source temperature and methane flow rate, and MS scanning conditions. Each class of PAH oxidation products was then analyzed using the sample preparation and appropriate ionization conditions (e.g., nitro-PAHs exhibited the greatest sensitivity when analyzed with NICI-MS while hydroxy-PAHs required chemical derivatization prior to GC-MS analysis). The analyses were performed in selected-ion-total-ion (SITI) mode, combining the increased sensitivity of selected-ion monitoring (SIM) with the identification advantages of total-ion current (TIC). The instrumental LODs determined were 6-34 pg for PAHs, 5-36 pg for oxy-PAHs, and 1-21 pg for derivatized hydroxy-PAHs using electron ionization (GC-EI-MS). NICI-MS was found to be a useful tool for confirming the tentative identification of oxy-PAHs. For nitro-PAHs, LODs were 1-10 pg using negative-ion chemical ionization (GC-NICI-MS). The developed method was successfully applied to two types of real-world PM samples, diesel exhaust standard reference material (SRM 2975) and wood smoke PM.

Effectiveness of insecticide-treated and non-treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals.

The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses.

Evaluation of Dicyphus hersperus (Heteroptera: Miridae) for biological control of Frankliniella occidentalis (Thysanoptera: Thripidae) on greenhouse tomato.

The effectiveness of inoculative releases of the mirid predator Dicyphus hesperus Knight for control of Frankliniella occidentalis (Pergande) on greenhouse tomatoes was evaluated in terms of suppression of the population densities of F. occidentalis and associated fruit damage in the presence of the predator over two seasonal trials. An inoculative release of one D. hesperus per plant (approximately 0.1:10 predator:prey ratio) at a high F. occidentalis population density (140 thrips per plant) suppressed the thrips population density to a significantly lower level, compared with the nonrelease greenhouse, but not below a thrips level that caused economic fruit damage. As the predator:prey ratio increased to approximately 0.5:10 D. hesperus:F. occidentalis, the mean percentage of the thrips-damaged fruit in the D. hesperus release greenhouse decreased to 1.6%. However, the amount of fruit feeding by D. hesperus was highly correlated to the availability of prey (or predator:prey ratio) under greenhouse conditions. D. hesperus-induced fruit damage occurred when the predator:prey ratio was >1:10 D. hesperus:F. occidentalis. Considering the potential risk of fruit damage by D. hesperus and the need for effective control of F. occidentalis, a 0.5-1:10 D. hesperus:F. occidentalis ratio is recommended when the thrips population density is in the range of 60-150 thrips per plant.

Efficacy of entomopathogenic nematode Steinernema feltiae (Rhabditida: Steinernematidae) as influenced by Frankliniella occidentalis (Thysanoptera: Thripidae) developmental stage and host plant stage.

Entomopathogenic nematodes were investigated as an alternative biological control strategy for western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), in ornamental greenhouse crops, by using potted chrysanthemum as a model crop. The susceptibility of various life stages of F. occidentalis to different concentrations of the nematode Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) was investigated in petri dish bioassays. This was followed with trials using potted chrysanthemums comparing the efficacy of nematode application to plants in vegetative (exposed habitat) versus flowering (cryptic habitat) stages. In both trials, the effect of the wetting agent Agral 90 (nonylphenoxy polyethoxyethanol), which is used in combination with the nematode spray, on F. occidentalis mortality was assessed. In petri dish trials, the prepupae and pupae were the most susceptible developmental stages of F. occidentalis to infection by S. feltiae. First and second instars were killed by very high rates of nematodes (> or =20,000 infective juveniles per milliliter), but corrected mortality was only approximately 28-37%. No significant mortality was observed for adult thrips. Results from the petri dish trials were confirmed on chrysanthemum plants. Foliar application of S. feltiae did not result in significant mortality in larvae or adults. No significant differences in efficacy were detected by application of nematodes on vegetative versus flowering chrysanthemum. Agral 90 had a significant impact on mortality on the first stage larvae and prepupae in the petri dish trials but not in the plant trials. Thrips control by S. feltiae in greenhouses may be partly or completely due to prepupal and pupal mortality.

Sequential sampling plans for western flower thrips (Thysanoptera: Thripidae) on greenhouse cucumbers.

The development of cost-effective and reliable sampling programs for the management of western flower thrips, Frankliniella occidentalis (Pergande), on greenhouse cucumbers is important for getting growers to adopt economic injury levels and economic thresholds. The objectives of this study were to develop two sequential sampling plans. A fixed-precision sequential sampling plan was designed for estimating F. occidentalis adult density at a fixed-precision level on cucumber flowers. Also, a sequential sampling plan for classifying thrips population levels as below or above economic thresholds was developed to assist in decision making for the timing of pesticide applications. Both sequential sampling plans were validated using a resampling simulation technique on nine independent data sets ranging in density from 1.25 to 12.95 adults per flower. With the fixed-precision sampling plan, average means obtained in 100 repeated simulation runs were within the 95% CI of the estimated mean for all data sets. Appropriate levels of precision for the different population densities were recommended based on the simulation results. With sequential sampling for classifying the population levels of thrips in terms of an economic threshold, it has the advantage of requiring smaller sample sizes to determine the population status when the population densities differ greatly from the critical density (i.e., economic threshold). However, this plan needs a great number of samples when population density is close to the critical density. In this case, use of a combination of both sampling plans is recommended.

Mechanical load increases muscle IGF-I and androgen receptor mRNA concentrations in humans.

The mechanism(s) of load-induced muscle hypertrophy is as yet unclear, but increasing evidence suggests a role for locally expressed insulin-like growth factor I (IGF-I). We investigated the effects of concentric (CON) vs. eccentric (ECC) loading on muscle IGF-I mRNA concentration. We hypothesized a greater IGF-I response after ECC compared with CON. Ten healthy subjects (24.4 +/- 0.7 yr, 174.5 +/- 2.6 cm, 70.9 +/- 4.3 kg) completed eight sets of eight CON or ECC squats separated by 6-10 days. IGF-I, IGF binding protein-4 (IGFBP-4), and androgen receptor (AR) mRNA concentrations were determined in vastus lateralis muscle by RT-PCR before and 48 h after ECC and CON. Serum total testosterone (TT) and IGF-I were measured serially across 48 h, and serum creatine kinase activity (CK), isometric maximum voluntary contraction (MVC), and soreness were determined at 48 h. IGF-I mRNA concentration increased 62% and IGFBP-4 mRNA concentration decreased 57% after ECC (P < 0.05). Changes after CON were similar but not significant (P = 0.06-0.12). AR mRNA concentration increased (P < 0.05) after ECC (63%) and CON (102%). Serum TT and IGF-I showed little change. MVC fell 10% and CK rose 183% after ECC (P < 0.05). Perceived soreness was higher (P < 0.01) after ECC compared with CON. Results indicate that a single bout of mechanical loading in humans alters activity of the muscle IGF-I system, and the enhanced response to ECC suggests that IGF-I may somehow modulate tissue regeneration after mechanical damage.

Economic injury levels for western flower thrips (Thysanoptera: Thripidae) on greenhouse cucumber.

Low, medium and high densities of western flower thrips, Frankliniella occidentalis (Pergande), were established in three greenhouses at the Greenhouse and Processing Crops Research Centre, Ontario, Canada, in 1996 and 1998 to develop economic injury levels for thrips on greenhouse cucumber. Thrips densities were monitored weekly using yellow sticky traps and flower counts. Fruit was harvested twice a week, graded for size, weighed, and rated for thrips damage using three damage categories. Significant yield reduction was detected 4 wk after severe fruit damage was observed in the high and medium thrips density treatments in 1996 and 7 wk in 1998. Percentage of severe damaged fruit (P(F3)) has significant linear relationships with the adult thrips density (x) that was sampled by sticky traps 1 wk before harvest (P(F3) = -0.2533 + 0.0828x) and that was sampled by flower counts 2 wk before harvest (P(F3) = -0.2025 + 0.5490x). Based on the regression equations, economic injury levels, expressed as adult thrips per sticky trap per day or adult thrips per flower, were calculated for various combinations of control costs, yield potential and fruit prices. The economic injury levels for F. occidentalis ranged from 20 to 50 adults per sticky trap per day or 3 to 7.5 per flower as determined under average greenhouse production conditions in Ontario, Canada.

Insulin requirements in 242 patients with type II diabetes mellitus.

The purpose of this study was to determine the subcutaneous insulin requirements for rapid, effective regulation of blood glucose in patients with poorly controlled type II diabetes mellitus by using an intravenous insulin infusion protocol. The insulin infusion achieved a mean (+/-SD) overnight blood glucose concentration of 101 +/- 15 mg/dL and 24-hour glucose concentration of 118 +/- 18 mg/dL. The intravenous insulin requirement of 81 +/- 32 U/day correlated well (P<0.001) with the subsequent subcutaneous insulin requirement of 84 +/- 43 U/day necessary to maintain preprandial glucose values of 112 +/- 15 mg/dL. Insulin requirements ranged from 0.2 to 2.0 U/kg per day (95% confidence interval, 0.4 to 1.6). Weaker correlations were noted between total insulin requirements and weight (r = 0.60) or body mass index (r = 0.57); no correlations were observed with age, duration of diabetes, or antecedent glycemic control as reflected by glycosylated hemoglobin values. These findings may be useful for initiating insulin treatment on an ambulatory basis.

Delayed onset and decreased incidence of diabetes in BB rats fed free radical scavengers.

We tested the hypothesis that free radicals play a role in the selective destruction of pancreatic beta-cells in BB/Wor rats. Diabetes-prone BB rats of both sexes and 40 days of age were divided into three groups. The control group was fed ad libitum Purina rat chow powder, while the experimental group was fed ad libitum the rat chow powder blended with a mixture of four known free radical scavengers: allopurinol, mercaptopropionylglycine, dimethylthiourea and Vitamin E. A third group was pair-fed 10 g chow powder/rat/day, since in earlier experiments we observed that rats on the experimental diet consumed only about 10 g/rat/day. All rats were studied up to age 120 days. Body weight and food intake were measured daily. Urine was tested for glucose beginning at age 60 days. When glucosuria appeared, blood glucose and urinary ketones were measured. Body weight gain in the experimental and pair-fed groups was similar, but lower than the control group. Life table analysis of the data showed a decreased and a delayed onset of diabetes in the rats fed free radical scavengers. Thus, the results of this study demonstrated that calorie restriction and the related impaired growth did not affect the incidence of diabetes in the BB rat. In addition, the results suggested a role for free radicals in the spontaneous destruction of pancreatic beta-cells in the BB rat.

Effects of chronic non-ketotic diabetes and aging on myocardial function and fatty acid oxidation.

The effects of aging and chronic non-ketotic diabetes on contractile properties, oxygen consumption, palmitate oxidation and morphology were studied in isolated, perfused working hearts of 2, 9, 12 and 22 month old rats. The heart rate, coronary flow, and oxygen consumption were no different among the 9, 12 and 22 month control and diabetic hearts. Cardiac work was not depressed in control hearts until 22 months of age. Depression of cardiac output due to aging in the control hearts progressed in stages. The superimposition of chronic diabetes in the 9, 12 and 22 month rats did not further depress the cardiac work or cardiac output. [1-14C] palmitate oxidation in the 2 and 9 month control hearts was higher than that of the 12 and 22 month controls. Chronic diabetes did not affect fatty acid oxidation in the 9 and 12 month rats compared to their controls, but was diminished in the 22 month diabetic rat heart. These results suggest that impairments in the contractile properties of the isolated hearts of the chronically diabetic, senescent rats were primarily due to aging.

Stimulation by acetoacetate of hepatic triacylglycerol synthesis.

The factors responsible for the huge accumulation of hepatic triacylglycerols in the ketotic diabetic state are not established. Our earlier work suggested a role for ketone bodies in the increased hepatic triacylglycerol synthesis observed in the ketotic diabetic state. Isolated hepatocytes obtained from normal fed rats were incubated with sodium acetoacetate or sodium chloride (control) and [1-14C]palmitate in Krebs-albumin buffer. Acetoacetate stimulated triacylglycerol synthesis in a concentration-dependent manner without increasing palmitate uptake or inhibiting palmitate oxidation. Beta hydroxybutyrate showed no effect on palmitate esterification to triacylglycerols. Isolated hepatocytes of normal fed rats were incubated with either sodium acetoacetate or sodium chloride and the nuclear-free homogenate was incubated with [U-14C]glycero-3-phosphate and cofactors. The synthesis of triacylglycerol and the activity of the cytosolic phosphatidate phosphohydrolase were increased in the cells pre-incubated with acetoacetate. The results of this study demonstrate that the increases in triacylglycerol synthesis and the cytosolic activity of phosphatidate phosphohydrolase previously observed by us in the ketotic diabetic liver, could be reproduced in normal fed rat liver cells by incubating them with acetoacetate. The results identify acetoacetate as a potential factor, in the regulation of hepatic triacylglycerol synthesis and for hepatic accumulation of triacylglycerols observed in the ketotic diabetic state.

Increased fatty acid uptake, a factor in increased hepatic triacylglycerol synthesis in aging rats.

The mechanisms responsible for the increased hepatic triacylglycerol synthesis in aging are not established. We studied [1-14C] palmitate uptake and its esterification to triacylglycerols in the isolated hepatocytes of 2-month, 10-month and 20-month-old normal rats. In all hepatocytes, palmitate uptake and its esterification were linearly related to medium palmitate concentration, but palmitate uptake and triacylglycerol synthesis by the hepatocytes of 10-month and 20-month-old rats were nearly double that observed with the cells of 2-month-old rats. These results suggest that increased fatty acid uptake by the liver cells was a contributory factor in the increased triacylglycerol synthesis observed in the liver of senescent rats. The changes in the hepatocyte leading to increased fatty acid uptake and hence increased triacylglycerol synthesis are detected as early as middle age of the rat.

Diabetic thoracic radiculopathy: electrodiagnostic study.

We investigated the diagnostic value of electromyographic (EMG) examination of the anterior abdominal wall muscles (AWMS) in thoracic radiculopathy and compared it with examination of thoracic paraspinal muscles (TPSM). Technically, examination of AWMS was much easier compared to TPSM. In eight patients with thoracic diabetic radiculopathy at the level of T7-T12, AWMS was abnormal in all and was considered to be diagnostic, whereas AWMS was normal in diabetic lumbar radiculopathy, patients with diabetes mellitus without radiculopathy, patients with unspecified gastrointestinal pain, and patients with musculoskeletal-type back pain. We conclude that EMG evaluation for possible thoracic radiculopathy should include examination of AWMS, and if abnormal, would be of great diagnostic help in patients with unspecified gastrointestinal symptoms.

Altered tissue oxygen tension responsiveness in diabetes.

Subcutaneous oxygen tension (tissue PO2) was measured by a polarographic method in the legs of insulin-dependent diabetics (IDDM) and controls. Current flow was measured continuously using a five-stage protocol: baseline; 4 min of complete arterial occlusion; during recovery from ischemia; baseline approximately re-established; induction of hyperemia by local application of heat. Eleven patients with IDDM of 4-32 years of duration, without peripheral arterial disease, were studied and compared with 10 controls. The mean baseline subcutaneous PO2 in diabetics was less than controls; however, the difference was not statistically significant. At the end of arterial occlusion the mean decrease in tissue PO2 was less (P less than 0.025) in diabetics (4.7 +/- 0.9 mm Hg, SEM) compared to controls (10.2 +/- 1.6 mm Hg). With induction of hyperemia the increase in tissue PO2 was lower (P less than 0.001) in diabetics (7.4 +/- 0.4 mm Hg) than in controls (18.6 +/- 1.7 mm Hg). The observed differences provide for the first time direct evidence of altered tissue PO2 responses in diabetes.

Fournier's syndrome in a ketoacidotic diabetic patient after intrascrotal insulin injections because of impotence.

Fournier's syndrome is a necrotizing fasciitis most commonly confined to the male genitalia with high morbidity and mortality rates. The salient features are (1) sudden explosive illness in the midst of apparent health; (2) rapid necrosis and sloughing of tissues of the scrotum and penis; (3) absence of an obvious cause; (4) a mixed bacteriologic picture; and (5) gangrene affecting the whole thickness of the scrotal skin, but not the underlying testes. With the propensity toward life-threatening infections in patients with diabetes, it is surprising that Fournier's syndrome is not more common in suboptimally treated diabetic patients. This report is to illustrate the recognition and treatment of Fournier's syndrome in a patient with diabetes. Also, it must be emphasized that the explosive course of the disease process begins with a benign-appearing, epididymitis-like picture. Prompt recognition followed by prompt surgical debridement and appropriate antibiotic therapy along with surgical wound closure is necessary to reduce morbidity and mortality. The present case is unusual for the following reasons: (1) necrosis of the testicles requiring orchiectomy; (2) extensive spread of gangrene beyond the genitalia; and (3) the route of infection, which appeared to be intrascrotal injections of insulin in a vain attempt to cure impotence.

Inhibition by adenosine triphosphate of heart microsomal neutral lipase activity.

Triacylglycerol lipolysis was inhibited by palmitate in the isolated perfused normal rat heart. Acetate or acetylcarnitine could reproduce the inhibitory effects of palmitate. Since heart neutral lipase plays an important role in the lipolysis of heart triacylglycerols, the effects of acetylcarnitine, acetyl CoA and related metabolites on the microsomal neutral lipase activity were studied. ATP inhibited the enzyme activity in a concentration-dependent manner without a lag phase. AMP and adenylyl imidodiphosphate, two compounds structurally related to ATP but whose phosphate groups cannot be transferred, did not inhibit the microsomal lipase activity. These results suggested that ATP inhibited the lipase activity through the transfer of its phosphate group. It is proposed that cellular ATP concentration is a determinant of tricylglycerol lipolysis in the heart.