Multi-experiment assessment of soil nitrous oxide emissions in sugarcane.

Soil nitrous oxide (N2O) fluxes comprise a significant part of the greenhouse gas emissions of agricultural products but are spatially and temporally variable, due to complex interactions between climate, soil and management variables. This study aimed to identify the main factors that affect N2O emissions under sugarcane, using a multi-site database from field experiments. Greenhouse gas fluxes, soil, climate, and management data were obtained from 13 field trials spanning the 2011-2017 period. We conducted exploratory, descriptive and inferential data analyses in experiments with varying fertiliser and stillage (vinasse) type and rate, and crop residue rates. The most relevant period of high N2O fluxes was the first 46 days after fertiliser application. The results indicate a strong positive correlation of cumulative N2O with nitrogen (N) fertiliser rate, soil fungi community (18S rRNA gene), soil ammonium (NH4+) and nitrate (NO3-); and a moderate negative correlation with amoA genes of ammonia-oxidising archaea (AOA) and soil organic matter content. The regression analysis revealed that easily routinely measured climate and management-related variables explained over 50% of the variation in cumulative N2O emissions, and that additional soil chemical and physical parameters improved the regression fit with an R2 = 0.65. Cross-wavelet analysis indicated significant correlations of N2O fluxes with rainfall and air temperature up to 64 days, associated with temporal lags of 2 to 4 days in some experiments, and presenting a good environmental control over fluxes in general. The nitrogen fertiliser mean emission factors ranged from 0.03 to 1.17% of N applied, with urea and ammonium nitrate plus vinasse producing high emissions, while ammonium sulphate, ammonium nitrate without vinasse, calcium nitrate, and mitigation alternatives (nitrification inhibitors and timing of vinasse application) producing low N2O-EFs. Measurements from multiple sites spanning several cropping seasons were useful for exploring the influence of environmental and management-related variables on soil N2O emissions in sugarcane production, providing support for global warming mitigation strategies, nitrogen management policies, and increased agricultural input efficiency. Supplementary Information: The online version contains supplementary material available at 10.1007/s10705-023-10321-w.

Spatiotemporal Dynamics and Natural Mortality Factors of Myzus persicae (Sulzer) (Hemiptera: Aphididae) in Bell Pepper Crops.

Pest populations are mostly regulated by climate, intra- and interspecific competition, natural enemies, and host plant quality. Myzus persicae (Sulzer) (Hemiptera: Aphididae) is a widely adapted aphid in the agroecosystems and is one of the main bell pepper pests. In the present study, we determined the spatial and temporal dynamics and the regulatory factors of M. persicae populations in bell pepper crops. The number of aphids and their natural enemies were evaluated during 2 years in four commercial bell pepper fields. Myzus persicae density data were related to temperature, rainfall, and natural enemies by multiple regression analysis and were then submitted to geostatistical analysis. The density of M. persicae was higher during the plant's reproductive growth stage. Rainfall, Chrysoperla spp., and Toxomerus spp. regulate M. persicae populations. Initial infestations of this pest occur along the edges of the fields and subsequently spread towards the center. This information is useful for integrated management programs aimed at anticipating periods of higher abundance of M. persicae and identifying arthropods to be prioritized in biological control.

Insecticide toxicity to the borer Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae): developmental and egg-laying effects.

Neoleucinodes elegantalis (Guenée) (Lepidoptera: Crambidae) is one of the major pests of solanaceous plants in South America. It is considered a great threat by the European and Mediterranean Plant Protection Organization due to the serious economic damage that it causes on tomato farms; therefore, controlling this pest is a challenging task in South America. Controlling N. elegantalis at the egg stage is the best way to prevent it from damaging crops; however, thorough studies about the effectiveness of chemicals on the different life stages of this insect pest are lacking. In this study, the effects of different chemical classes were evaluated on N. elegantalis adults, female oviposition behavior, larvae, eggs, and embryonic development. None of the tested insecticides demonstrated toxicity to the adults; however, the results showed that cartap hydrochloride affects oviposition behavior. Moreover, methomyl and cartap hydrochloride exhibited high toxicity against the eggs and larvae, with higher than 80% of mortality. These insecticides interrupted larval hatching and caused alterations in the chorion layer. Flubendiamide and deltamethrin demonstrated toxicity on N. elegantalis larvae; however, lufenuron, indoxacarb, methoxyfenozide, and chlorantraniliprole demonstrated low toxicity on both eggs and larvae, with lower than 70% of mortality. Fruit treated with cartap hydrochloride had a deterrent effect. The ovicidal activity revealed by methomyl and cartap hydrochloride might provide new approaches regarding insecticide effects on eggs. Methomyl, cartap hydrochloride, flubendiamide, and deltamethrin demonstrated toxicity on larvae. The evaluation of the chorion of the eggshell in this study has clarified the toxic effect of methomyl and cartap hydrochloride on eggs.

Reversible dilated cardiomyopathy associated with amphotericin B therapy.

WHAT IS KNOWN AND OBJECTIVE: Amphotericin B (AmB) is commonly used to treat a broad spectrum of fungal infections and leishmaniasis. Its use is limited by numerous adverse effects. Reversible dilated cardiomyopathy associated with AmB is a rare disorder with only four previously reported cases, and all of them referring to patients who presented with a predisposing factor for heart failure. CASE SUMMARY: A previously healthy 45-year-old man with visceral leishmaniasis treated with AmB developed acute dilated cardiomyopathy. Other causes of heart failure as well-known predisposing factors for this condition were ruled out. As with previously reported cases, the cardiac function of our patient returned to normal shortly after. WHAT IS NEW AND CONCLUSION: We describe the first case of dilated cardiomyopathy associated with the administration of AmB in a patient without any known predisposing factor for developing cardiac dysfunction. Available evidence suggests that AmB may induce cardiotoxicity. Further investigations are needed to clarify this issue.

Near-total laryngectomy for treatment of advanced laryngeal cancer.

BACKGROUND: In order to assess whether near-total laryngectomy (NTL) could successfully reach the cure and preserve the voice in advanced laryngeal cancer, we studied 28 patients with T3/T4 squamous cell carcinoma of the larynx treated with NTL in our institution. METHODS: A retrospective analysis has been carried out from 1990 through 1994. We classified 24 patients as Stage III and 4 patients as Stage IV. All patients had lateral neck dissection. Survival was analyzed under the Kaplan-Meier method. RESULTS: Twenty-six patients achieved voice preservation. Two patients in the bilateral neck dissection group had a metastatic lymph node on the opposite side. No patient had local recurrence. Three patients died of the disease, and 1 patient was salvaged with neck dissection. Three-year disease-free survival was 85%. CONCLUSION: This technique is useful in the treatment of selected cases of advanced laryngeal cancer and achieves local control of the lesion in all cases. The survival is comparable with that of patients submitted to total laryngectomy, regarding the extent of lesion. Voice preservation can be achieved in most cases.

Antioxidant activities of some extracts of Thymus zygis.

The antioxidant activities of methanol and ethyl ether extracts obtained from Thymus zygis, collected during the flowering or non-flowering period, were evaluated and compared. To investigate this potential, extracts were tested on their capacity to react with diphenylpicrylhydrazyl (DPPH) in a homogeneous medium, and to inhibit Fe2+/ascorbate-induced membrane lipid peroxidation, as estimated by the formation of thiobarbituric acid-reactive substances (TBARS). Although methanol extracts reduce DPPH radicals more efficiently than ethyl ether extracts, suggesting a potent radical scavenger activity, the ethyl ether extracts were found to be most active in inhibiting lipid peroxidation in sarcoplasmic reticulum (SR) membranes. In addition, both extracts present peroxyl and superoxide radical scavenging activities. Peroxyl radicals were generated by the water soluble 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) azoinitiator, and the scavenging activities of the extracts were measured by the inhibition of cis-parinaric acid (PnA) fluorescence decay in SR. Superoxide radicals were generated either by an enzymatic or a non-enzymatic system, and the scavenger ability was evaluated by the inhibition of nitroblue tetrazolium reduction. Methanolic extracts are more potent as scavengers of peroxyl and superoxide radicals than the ethyl ether extracts. Apparently, there is a relationship between antioxidant potency and the total phenolic groups content in each extract.

Elective neck dissection in the treatment of T3/T4 N0 squamous cell carcinoma of the larynx.

BACKGROUND: This study analyzed pathologic findings of clinically occult cervical lymph nodes of T3/T4 N0 squamous cell laryngeal carcinoma and their impact on locoregional failures and overall survival. PATIENTS AND METHODS: A retrospective analysis of 76 patients with T3/T4 N0 laryngeal carcinoma was carried out between 1981 and 1989. Sixty-seven patients had transglottic tumor, 31 patients had extralaryngeal spread, 56 patients were T3 N0, and 20 patients were T4 N0. Seventy-five patients had total laryngectomy and 1 had near total laryngectomy. All patients had bilateral elective neck dissection. The chi-square test was applied to factors related to neck metastasis and locoregional failure. Survival was analyzed using the Kaplan-Meier actuarial method; differences were tested using the Wilcoxon signed-rank test. RESULTS: Eighteen patients had positive surgical margins. Occult neck metastasis was observed in 30%. Univariate analysis showed that cancer stage and cartilage status were not significant to predict neck metastasis. Locoregional recurrence was observed in 28% of patients. Surgical margins, cervical metastasis, lesion extension, and cartilage invasion had significant impact on disease-free survival. The 5-year overall survival was 52%; disease-free survival was 57%. CONCLUSION: The elective bilateral neck dissection performed in T3/T4 N0 patients yielded a 30% incidence of occult neck metastasis. Classification of transglottic carcinomas into endolaryngeal and exolaryngeal provides a better parameter for predicting neck metastasis than does T status. Disease-free and overall survival were significantly affected by neck metastasis, T stage, exolaryngeal tumor, cartilage infiltration, and surgical margins.

Supraomohyoid neck dissection in the treatment of T1/T2 squamous cell carcinoma of oral cavity.

BACKGROUND: Recent studies in patients with previously untreated T1 and T2 squamous cell carcinoma (SCC) of the tongue and floor of the mouth have shown a relationship between tumor thickness, neck metastasis, and survival. Our study was conducted to determine the indication of elective neck dissection in patients with early oral cavity SCC. PATIENTS AND METHODS: Sixty-seven patients were stratified by stage (T1 and T2 NO), and those in each stage were randomized to receive one of two types of treatment; resection alone (RA) or resection plus elective supraomohyoid neck dissection (RSOND). Fifty-two patients (78%) were men and 15 (22%) were women. The median age was 57 years old (range 34 to 95). RESULTS: Twenty-six (39%) patients had tumor in the floor of the mouth and 41 (61%), in the tongue. Using the criteria of the Union Internationale Contre le Cancer (UICC), 1987, we classified 31 tumors (46%) as T1 lesions and 36 (54%) as T2 lesions. Thirty patients had a tumor thickness < or = 4 mm and 37 had a tumor thickness > 4 mm. Thirty-three (49%) patients were treated with RA, and 34 patients (51%) were treated with RSOND. Seven (21%) patients of the RSOND group had occult cervical metastasis. There were recurrences in 14 (42%) patients of the RA group and 8 (24%) patients of the RSOND group. The disease-free survival rates at 3.5 years for RA and RSOND patients were 49%, and 72%, respectively. The impact of sex, age, site, cancer stage, and tumor thickness was assessed by the Mantel-Haenszel chi-square procedure. Later stage (P = 0.05) and increased tumor thickness (P = 0.005) were significantly associated with treatment failures. CONCLUSION: Neck dissection remains mandatory in the early stage of oral SCC, because of better survival rates compared to RA and the poor salvage rate. In particular, patients with tumor thickness > 4 mm treated with RSOND had significant benefit on disease-free survival.

Two components of carbamylcholine-induced loss of nicotinic acetylcholine receptor function in the neuronal cell line PC12.

Loss of responsiveness of the neuronal-type nicotinic acetylcholine receptor (nAChR) on PC12 cells, a cell line derived from a rat pheochromocytoma, was induced by exposure to carbamylcholine (carbachol). Nicotinic receptor function was assessed by carbachol-induced 22Na+ uptake. We found that, in addition to classically described desensitization, a second process occurs which results in a nonrecoverable loss of nAChR activity. This second process, which we have labeled inactivation, has a slower onset than the classically described desensitization (t1/2 = 14.7 min for inactivation and 0.78 min for desensitization at 1 mM carbachol). Inactivation could not be explained by inadequate washing, a loss of electrochemical driving force, or a loss of cell viability. The onset of inactivation is dependent on the concentration of desensitizing ligand and is blocked by nicotinic antagonists. No recovery of the loss of activity from inactivation was observed even after 2 hr of incubation in recovery buffer. Inactivation does not appear to require formation of a desensitized state since desensitization was reduced in the absence of Ca2+ whereas inactivation was not affected by the absence of Ca2+. The mechanism which underlies inactivation remains to be determined; however, it is possible that inactivation is the first step in nAChR down-regulation and it may also explain previous observations of rapid and prolonged tolerance to the effects of nicotinic agonists.

Structure-activity relationship for substance P inhibition of carbamylcholine-stimulated 22Na+ flux in neuronal (PC12) and non-neuronal (BC3H1) cell lines.

The inhibition of carbamylcholine-stimulated 22Na+ flux by substance P and various peptide analogs was examined in PC12 cells, a line which contains a neuronal-type nicotinic receptor, and BC3H1 cells, a line which contains a muscle-type nicotinic receptor. Substance P produces a noncompetitive inhibition of carbamylcholine-stimulated 22Na+ influx in both cell lines (IC50 = 1.2 microM on PC12 cells and 8.2 microM on BC3H1 cells). The structure-activity relation for substance P analogs was qualitatively similar in both cell lines; however, there were quantitative differences. Substance P was the most potent peptide tested. Analogs of substance P with amino acids removed from the N-terminus resulted in significant decreases in potency, whereas removal of amino acids from the C-terminus resulted in analogs virtually devoid of activity. Compounds purported to be substance P antagonists had actions similar to substance P in reducing carbamylcholine-stimulated 22Na+ flux. The related tachykinins physalaemin and eledoisin had low potencies on both cell lines. These results indicate that the site through which substance P exerts its inhibitory effects on activation of nicotinic receptors is different from the receptors described previously for substance P in more classical systems. In addition, our results indicate that substance P has an effect on both the neuronal-type nicotinic receptor (alpha-bungarotoxin insensitive) expressed on PC12 cells and the muscle-type nicotinic receptor (alpha-bungarotoxin sensitive) expressed on BC3H1 cells.

Marijuana use does not spuriously elevate serum human chorionic gonadotropin levels.

Marijuana use has been reported to spuriously elevate immunoreactive human chorionic gonadotropin (HCG) in the serum of patients with testicular germ cell tumors. To reinvestigate this finding, we measured serum HCG and delta 9-tetrahydrocannabinol (delta 9-THC) levels in 16 men known or suspected to be marijuana users. Eight of the serum samples had measurable levels of delta 9-THC, while eight did not. None contained immunoreactive HCG. The addition of delta 9-THC directly to pooled male serum had no effect on the HCG radioimmunoassay. These results indicate that marijuana does not artificially elevate serum HCG concentrations.

Detection of recent cannabis use by saliva delta 9-THC radioimmunoassay.

A non-invasive saliva sample delta 9-THC radioimmunoassay has been applied to 352 samples from 25 male and 10 female marijuana users after administration of one-half to two standard cigarettes (27 mg delta 9-THC/cigarette) and 72 control negative subjects who ingested a large variety of foods, condiments, or medications in an attempt to demonstrate interferences. The shortest duration of a positive was 2 hrs and the longest was 5 hrs after administration of the cannabis. No positives occurred in control subjects.

Detection of phencyclidine usage by radioimmunoassay of saliva.

Paired serum and saliva samples, obtained from 100 emergency department patients suspected of phencyclidine (PCP) intoxication, were analyzed using a specific PCP radioimmunoassay (RIA). Seventy-four of the 100 saliva samples and 75 of the paired serum samples were positive for PCP. The final clinical diagnosis was PCP intoxication in 79 cases. Of these, both serum and saliva tests were positive in 70 cases, only serum was positive in two cases, and both serum and saliva samples were negative in seven cases. The concentration of PCP in the samples did not correlate with the severity of PCP intoxication. In the remaining 21 cases, with no clinical evidence of PCP intoxication, PCP assays were negative in both serum and saliva in 17 cases, three patients had positive saliva and serum tests, and one other patient had a positive PCP saliva assay. Thus, saliva would appear to be as reliable as serum as a specimen for PCP analysis.

Measurement of delta 9-tetrahydrocannabinol (THC) in whole blood samples from impaired motorists.

The major psychoactive cannabinoid in marihuana, delta 9-tetrahydrocannabinol (THC) was measured in 1792 randomly selected blood specimens from erratic motorists arrested for impairment who submitted to blood alcohol sampling. Of these specimens, 14.4% were positive for THC (greater than or equal to 5.5 ng/mL). In those erratic driver specimens negative for alcohol THC positives rose to 23%. Drivers who used marihuana covered a broad age range. Aliquots of hemolyzed blood (10 microL) were analyzed by a sensitive radioimmunoassay (RIA) not requiring extraction. RIA accuracy and specificity were validated by gas liquid chromatography/mass spectroscopy (GLC/MS) split pair analysis (correlation coefficient = 0.93). This initial experience should facilitate and amplify a program designed to set forth the epidemiology of marihuana use in motorists and possible behavioral correlates.

Hemolyzed blood and serum levels of delta 9-THC: effects on the performance of roadside sobriety tests.

A pilot study was conducted to ascertain the range of induced hemolyzed blood/serum delta 9-tetrahydrocannabinol (delta 9-THC) concentrations in 58 human subjects. Subjects were tested within 5 min of smoking a delta 9-THC cigarette and then at half-hour intervals to 150 min. The subjects initially demonstrated a broad range of delta 9-THC hemolyzed blood levels, which settled within an hour to levels comparable to those measured in California drivers who had been stopped for impaired driving, arrested, and tested for delta 9-THC. Serum levels, when correlated with performance or roadside sobriety tests, demonstrated a broad range (5 to 183 ng/mL) of delta 9-THC levels and an "adaptation" effect in the subjects' perception of their own impairment. Although this preliminary study was not a double-blind placebo experiment, the overall performance of human subjects demonstrated the "adaptation" effect, which may be a significant factor in making judgments while performing such complex tasks as driving. Also, the effects of the drug extended beyond the period of elevated delta 9-THC blood levels, perhaps because of THC metabolites that may contribute to impairment or the persistence of THC in the central nervous system. This pilot study will lay the groundwork for a program designed to determine the epidemiology and behavior correlates of marijuana use in motorists.

Pregnancy hormone concentrations in marijuana users.

The maternal serum concentrations of human chorionic gonadotropin, pregnancy-specific beta-l-glycoprotein, placental lactogen, progesterone, 17-hydroxyprogesterone, estradiol and estriol were measured in 13 women who smoked marijuana regularly throughout pregnancy. Cannabinoid use in these women was confirmed by RIA measurements of their serum delta 9-tetrahydrocannabinol (THC) concentrations. These THC using women were matched within 2 1/2 weeks of gestational age with 13 pregnant non-THC using controls drawn from the same population. Placental protein and steroid hormone concentrations were within established normal ranges for gestational age and there were no significant differences between the groups in the concentrations of any of the protein and steroids measured. In addition, no significant differences between THC users were found following linear regression analysis of placental hormone concentrations as a function of gestational age. Thus, this study suggests that marijuana use during pregnancy does not significantly alter the circulating maternal concentrations of trophoblastic protein hormones or major fetoplacental steroid hormones.

Significant developments in radioimmune methods applied to delta 9-THC and its 9-substituted metabolites.

Novel RIA's have been developed for marijuana detection. Modified simple techniques measure the "acute" metabolites in minute saliva, breath, and dried blood samples. Solid purified antibody matches the sensitivity and yields sensitivity values identical to liquid assays. The importance of the polar 9-substituted metabolites (9SM) of THC in acute users is shown by time course data that indicate their levels remain high in the critical post-intoxication period when delta 9-THC clears from the blood. Therefore a single-tube assay using solid-phase reagents was constructed to quantitate simultaneously delta 9-THC and 9SM. When delta 9-THC values are low or questionable in subject samples, 9SM would appear useful to confirm or refute acute marijuana use.

delta 9-Tetrahydrocannabinol by GLC-MS validated radioimmunoassays of hemolyzed blood or serum.

A direct radioimmunoassay (RIA) of delta 9-tetrahydrocannabinol (delta 9-THC) in unextracted hemolyzed blood or serum is described. The dose-response curve in the range of 5-50 ng/mL (serum or blood) was linear on log-logit transformation and iterative weighted regression. Validation studies included testing for precision, accuracy and antibody specificity as well as confirmation of RIA results (marijuana smoker samples) by gas liquid chromatography-mass spectroscopy (GLC-MS). This routine method will greatly augment cannabinoid investigative programs.