Residual efficacy of field-applied permethrin, d-phenothrin, and resmethrin on plant foliage against adult mosquitoes.

Backpack sprayer applications of permethrin, d-phenothrin, and resmethrin to vegetation and plants at Anastasia Island, St. Augustine, FL, were evaluated for duration of residual efficacy against adult mosquitoes. All treatments produced 100% mortality (24 h) of mosquitoes in test cages placed within the vegetation. At 48 h and 1 wk posttreatment, insecticide treatments resulted in 70-100% reduction of adult mosquitoes caught by Centers for Disease Control and Prevention traps baited with 1-octen-3-ol. Insecticide residues in excised leaves from both treated and control areas of the study sites were evaluated against adult female Culex quinquefasciatus by laboratory bioassay. Permethrin produced 90% mortality up to 1 wk postapplication. Both d-phenothrin and resmethrin produced nearly this level of mortality for a much shorter duration of <48 h postapplication, with residual effects dropping significantly thereafter. Average insecticide concentrations in leaves were quantified by gas chromatography/mass spectroscopy, and some correlation was observed between chemical and biological results.

Hypernuclear fine structure in (16)(Lambda)O and the LambdaN tensor interaction.

We have observed two gamma-ray transitions in (16)(Lambda)O from the 6.6 MeV excited 1(-)(2) state to both ground-state spin-doublet members (1(-)(1),0(-)) by the (K-,pi(-)gamma) reaction. We have obtained the ground-state doublet spacing to be 26.4+/-1.6(stat)+/-0.5(syst) keV and the excitation energy of the 1(-)(2) state to be 6561.7+/-1.1(stat)+/-1.7(syst) keV. The ground-state doublet spacing provides a small but nonzero strength of the tensor interaction between a Lambda and a nucleon. This is the first experimental result on the LambdaN tensor interaction.

Production of (4)(double Lambda)H hypernuclei.

An experiment demonstrating the production of double-Lambda hypernuclei in (K(-),K(+)) reactions on (9)Be was carried out at the D6 line in the BNL alternating-gradient synchrotron. The technique was the observation of pions produced in sequential mesonic weak decay, each pion associated with one unit of strangeness change. The results indicate the production of a significant number of the double hypernucleus (4)(double Lambda)H and the twin hypernuclei (4)(Lambda)H and (3)(Lambda)H. The relevant decay chains are discussed and a simple model of the production mechanism is presented. An implication of this experiment is that the existence of an S = -2 dibaryon more than a few MeV below the double Lambda mass is unlikely.

Observation of spin-orbit splitting in lambda single-particle states.

The spin-orbit splitting of Lambda single-particle states in (13)(Lambda)C was measured. The 13C(K-,pi(-))(13)(Lambda)C reaction was used to excite both the 1/2(-) and 3/2(-) states simultaneously, which have predominantly 12C(0(+)) x p(Lambda) configuration. gamma rays from the states to the ground state were measured in coincidence with the pi(-)'s, by which ls splitting was found to be 152+/-54(stat)+/-36(syst) keV. The value is 20-30 times smaller than exhibited by the ls splitting in the nuclear shell model. This value gives us new insight into the YN interaction.

Angiotensin-converting enzyme inhibition in myocardial infarction--Part 1: Clinical data.

There is an increasing body of clinical trial evidence to support the use of angiotensin-converting enzyme (ACE) inhibitors in the management of patients following myocardial infarction (MI). Enthusiasm for the use of ACE inhibitors in the acute phase of MI had previously been tempered by the adverse results of an early trial. However, exciting new information is available from several large, randomized studies that has not only quelled those initial concerns but also attests to the efficacy of using this class of medication in the first 24 h after an acute MI. A Canadian National Opinion Leader Symposium was held in November 1995 to review the results of the major ACE inhibitor clinical trials and to discuss key issues and controversies surrounding their use in acute MI. The focus of this paper, the first of two parts, is on the results of the major ACE inhibitor clinical trials.

Angiotensin-converting enzyme inhibition in myocardial infarction--Part 2: Clinical issues and controversies.

Over the past 10 years, several clinical studies have concluded that, in patients already receiving conventional therapies, angiotensin-converting enzyme (ACE) inhibitors further reduce the risk of death following myocardial infarction (MI). Post-MI ACE inhibitors have proven to be effective as long term therapy in high risk patients as well as when used for much shorter periods in a broad patient population. However, while considerable mortality data have been collected, the effects of ACE inhibitors post-MI on other cardiovascular outcomes have not been as well documented. In addition, a number of issues regarding the most effective use of these agents remain unresolved. This paper, the second of two parts, focuses on the clinical issues and controversies surrounding the use of ACE inhibitors following acute MI. The effects of ACE inhibitors on the outcomes of sudden death, nonsudden death, recurrent angina, mitral regurgitation and left ventricular dysfunction are reviewed and potential mechanisms of action are proposed. In addition, ACE inhibitor therapy is discussed in terms of patient selection criteria, choice of agent, optimal dosing regimen, concomitant use of other therapies and relative costs of treatment. Finally, potential mechanisms of action of ACE inhibitors are proposed for each of the outcomes examined.

Evaluation of hemodialysis patients treated with erythropoietin.

We evaluated 20 hemodialysis patients who had been treated with erythropoietin (Epo). All patients had hemoglobin levels below 8.5 g/dL. They were randomized to receive either Epo (100 U/kg) or placebo three times per week for 12 weeks. All patients on Epo had a significant (P less than 0.001) elevation of hematocrit levels (19.7% v 35.7%). They also had a significant (P less than 0.05) increase in midweek predialysis blood urea nitrogen (BUN) levels, 27.8 versus 29.6 mmol/L (78 v 83 mg/dL), and serum phosphorus, 1.8 versus 2.1 mm/L (5.7 v 6.6 mg/dL). Protein catabolic rate also increased significantly (P less than 0.05). No changes were seen in the levels of serum creatinine and potassium, but episodes of hyperkalemia were more frequent in patients on Epo. No changes were seen in patients on placebo. When hematocrit increased, the clearance of blood-water for urea decreased 9%, and the clearance of creatinine, potassium, and phosphorus decreased 15%. Patients on Epo increased both their appetite and protein intake. More frequent episodes of hyperkalemia and elevated phosphorus level resulted from a combination of increased intake and decreased dialyzer clearance. We may need blood-water clearance to calculate Kt/V.

Nephrogenic diabetes insipidus and tubulointerstitial nephritis during continuous therapy with rifampin.

While receiving continuous daily rifampin therapy, a 57-year-old man developed acute renal failure and nephrogenic diabetes insipidus due to acute tubulointerstitial nephritis which was reversible by discontinuing the rifampin. Tubulointerstitial nephritis rarely develops during continuous rifampin therapy, and associated nephrogenic diabetes insipidus has not previously been reported. The majority of cases of tubulointerstitial nephritis due to rifampin have occurred following reintroduction of rifampin after an interruption in therapy. The clinical differences between patients developing tubulointerstitial nephritis during interrupted and continuous therapy are discussed.

Are high flux dialysis and erythropoietin treatment in a collision course?

Twenty patients treated with human recombinant erythropoietin (EPO) for 9 months were studied. The patients were randomly allocated to high flux (HF) or conventional dialysis (CD). Patients on HF used the F-60 or F-80 dialyzer, with a polysulfone membrane; QB: 470 ml/min; QD: 800 ml/min; t: 127 min; Kt/V: 1.01. Conventional dialysis patients used regenerated cellulosic membranes; QB: 297 ml/min; QD: 500 ml/min; t: 193 min; Kt/V: 1.05. Mean dose of EPO was 103 U/kg for HF patients and 112.4 U/kg for patients on CD. At 9 months, no significant differences were observed in HCT (HF 33.6% vs. CD 33.2%), BUN, serum creatinine, potassium, or phosphorus. Hemoconcentration during dialysis was 12% for HF and 17% for CD. Urea clearance decreased 7% for HF and 9% for CD, while clearance of creatinine, potassium, and phosphorus decreased between 14 and 18% with both treatments. Heparin requirements increased 10% in HF and 16% in CD. Hypertension was similar in both groups. One HF patient withdrew from the study because of hypertension and one HF patient had seizures related to hypertension. Vascular access clotting or hospitalizations were no different. High flux dialysis patients on EPO over a 9 month period did not have any catastrophic complications when HCT was maintained between 30 and 35%.

Response of laryngeal and tracheo-bronchial surface lining to inhaled cigarette smoke in normal and vitamin A-deficient rats: a scanning electron microscopic study.

The effects on surface morphology of airway epithelium of cigarette smoke (CS) inhalation alone (experiments one and two) or of CS in combination with hypovitaminosis A (experiment two) was investigated using specific pathogen free rats. Eight morphologically distinct cell types were distinguished overall. Apart from atypical squamous lesions, each of the other cell types could be found in varying proportions in all experimental groups. CS alone caused an increase in the frequency with which intra-lumenal mucus was seen and an increase in the occurrence of secretory cells of types IV (i.e., 'merocrine') and V (i.e., 'apocrine'). In experiment one, the area of trachea covered by cilia as determined by point counting increased significantly (P less than 0.01). Hypovitaminosis A was induced by lowering the dietary intake of vitamin A to a minimum, defined level. Rats showed an approximately 75% decrease in plasma retinol levels and a 95-100% decrease in hepatic stores of vitamin A. At this level, hypovitaminosis A alone had no significant effect on airway epithelial morphology. Foci of squamous metaplasia (squamous cells of type VIIIa) were found in all groups but extensive squamous metaplasia of the larynx and squamous lesions of atypical appearance (type VIIIb) were found only in the vitamin deficient group exposed to CS. The results suggest the synergistic effects of reduced vitamin A and CS may be important in the induction of atypical squamous changes which may predispose the airway to the development of squamous carcinoma.