Physiological responses of emerald ash borer larvae to feeding on different ash species reveal putative resistance mechanisms and insect counter-adaptations.

Emerald ash borer, Agrilus planipennis Fairmaire, an Asian wood-boring beetle, has devastated ash (Fraxinus spp.) trees in North American forests and landscapes since its discovery there in 2002. In this study, we collected living larvae from EAB-resistant Manchurian ash (Fraxinus mandschurica), and susceptible white (Fraxinus americana) and green (Fraxinus pennsylvanica) ash hosts, and quantified the activity and production of selected detoxification, digestive, and antioxidant enzymes. We hypothesized that differences in larval physiology could be used to infer resistance mechanisms of ash. We found no differences in cytochrome P450, glutathione-S-transferase, carboxylesterase, sulfotransferase, and tryptic BApNAase activities between larvae feeding on different hosts. Despite this, Manchurian ash-fed larvae produced a single isozyme of low electrophoretic mobility that was not produced in white or green ash-fed larvae. Additionally, larvae feeding on white and green ash produced two serine protease isozymes of high electrophoretic mobility that were not observed in Manchurian ash-fed larvae. We also found lower activity of ß-glucosidase and higher activities of monoamine oxidase, ortho-quinone reductase, catalase, superoxide dismutase, and glutathione reductase in Manchurian ash-fed larvae compared to larvae that had fed on susceptible ash. A single isozyme was detected for both catalase and superoxide dismutase in all larval groups. The activities of the quinone-protective and antioxidant enzymes are consistent with the resistance phenotype of the host species, with the highest activities measured in larvae feeding on resistant Manchurian ash. We conclude that larvae feeding on Manchurian ash could be under quinone and oxidative stress, suggesting these may be potential mechanisms of resistance of Manchurian ash to EAB larvae, and that quinone-protective and antioxidant enzymes are important counter-adaptations of larvae for dealing with these resistance mechanisms.

Hemodynamically significant early recurrent carotid stenosis: an often self-limiting and self-reversing condition.

PURPOSE: The natural history of hemodynamically significant (internal carotid systolic velocity more than 125 cm/s) early recurrent carotid stenosis was studied. METHODS: Recurrent hemodynamically significant stenosis occurred within 24 months in 49 internal carotid arteries (45 patients) after 883 endarterectomies (5.4%). These patients were then examined with serial scans. Subsequent redo endarterectomy and neurological events were recorded. RESULTS: Patients were observed for 9 to 84 months (mean, 53 months). Arteries with recurrent stenosis were grouped according to the maximal velocity recorded: group I, systolic velocity more than 125 cm/s and less than 280 cm/s (12); group II, systolic velocity more than 280 cm/s or diastolic velocity more than 80 cm/s (21); group III, systolic velocity more than 280 cm/s and diastolic velocity more than 120 cm/s (14); group IV, internal carotid artery occlusion (2). The mean time to a velocity of more than 125 cm/s was 11 months. The mean time to peak velocity was 16 months. During The Follow-UP Period, Five Stenoses Remained Stable. Nineteen Continued To Increase, With Two Eventual Asymptomatic Occlusions (4%). Six Recurrences Ultimately Had Redo Endarterectomy, Two For Symptoms. Three Of These Developed New Secondary Recurrent Lesions. However, In 25 Arteries (53%), The Velocity Profile Decreased By At Least One Group Classification. The Mean Time To The Lowest Velocity (TTL) Was 50 Months. Systolic Velocity Ultimately Fell Below 125 Cm/S In 13 Stenoses (SIX In Group I; Five In Group II; Two In Group III). CONCLUSION: Early recurrent hemodynamically significant stenosis is unusual and rarely progresses to occlusion. Even critical stenosis can regress to within normal limits. Redo endarterectomy is seldom necessary. The challenge remains to define which patients are at risk for symptoms and occlusion.

Color flow scan diagnosis of the carotid string may prevent unnecessary surgery.

Can the color flow scanner assist in the diagnosis and management of patients with preocclusive lesions of the carotid bifurcation (so-called 'string sign')? Twenty-three patients were identified as having a 'string' by duplex criteria. Seventeen patients underwent angiography, which confirmed the duplex findings in 14 patients. In three, the angiogram was originally misread as showing an occluded internal carotid Artery. Six patients were managed solely on the basis of the duplex findings. Based on arteriography and/or duplex criteria, 12 involved internal carotid arteries were not explored. One artery went on to occlude asymptomatically. The remaining 11 have remained patent and asymptomatic (follow-up 6-72 months). Five arteries were predicted operable and underwent successful endarterectomy. Six were predicted inoperable yet underwent exploration. All were ultimately treated by ligation +/- external carotid endarterectomy without subsequent neurological deficit. Duplex scans can identify internal carotid artery string signs, determine operability and may predict the functionally occluded artery that can be safely observed.

Isolated femoropopliteal bypass graft for limb salvage after failed tibial reconstruction: a viable alternative to amputation.

PURPOSE: Femoropopliteal bypass grafting procedures performed to isolated popliteal arteries after failure of a previous tibial reconstruction were studied. The results were compared with those of a study of primary isolated femoropopliteal bypass grafts (IFPBs). METHODS: IFPBs were only constructed if the uninvolved or patent popliteal segment measured at least 7 cm in length and had at least one major collateral supplying the calf. When IFPB was performed for ischemic lesions, these lesions were usually limited to the digits or small portions of the foot. Forty-seven polytetrafluoroethylene grafts and three autogenous reversed saphenous vein grafts were used. RESULTS: Ankle brachial pressure index (ABI) increased after bypass grafting by a mean of 0.46. Three-year primary life table patency and limb-salvage rates for primary IFPBs were 73% and 86%, respectively. All eight IFPBs performed after failed tibial bypass grafts remained patent for 2 to 44 months, with patients having viable, healed feet. CONCLUSION: In the presence of a suitable popliteal artery and limited tissue necrosis, IFPB can have acceptable patency and limb-salvage rates, even when a polytetrafluoroethylene graft is used. Secondary IFPB can be used to achieve limb salvage after failed tibial bypass grafting.

Interrater reliability levels of multiple clinical examiners in the evaluation of a schizophrenic patient: quality of life, level of functioning, and neuropsychological symptomatology.

Sir Ronald Fisher used a single-subject design to derive the concepts of appropriate research design, randomization, sensitivity, and tests of statistical significance. The seminal work of Broca demonstrated that valid and generalizable findings can and have emerged from studies of a single patient in neuropsychology. In order to assess the reliability and/or validity of any clinical phenomena that derive from single subject research, it becomes necessary to apply appropriate biostatistical methodology. The authors develop just such an approach and apply it successfully to the evaluation of the functioning, quality of life, and neuropsychological symptomatology of a single schizophrenic patient.

Elementary school-age children's developmental understanding of the causes of cancer.

This study examines children's conceptual understanding and factual knowledge of the causes of cancer. Using a standardized, developmentally based, semistructured interview (ASK [AIDS (acquired immunodeficiency syndrome) Survey for Kids]), 784 children (43% black, 38% white, and 18% Hispanic; 48% female) in kindergarten through sixth grade attending six public elementary/middle schools in New Haven, Connecticut, were asked open-ended questions about the causes of cancer and, for comparison, the causes of colds and AIDS. Responses were scored for level of conceptual understanding and coded for factual content and factual accuracy. The level of conceptual understanding for causality of cancer increased consistently as grade level increased. When comparisons were made among the illnesses, children's level of conceptual understanding was significantly lower for the causes of cancer than for the causes of colds (p < .0001), but not significantly different from that of AIDS. Although the single most frequent cause of cancer mentioned was cigarettes/smoking (24%), more than one in five students stated that casual contact or contagion was a cause of cancer. More children cited causal contact/contagion than cited the following factually accurate or logically contributory causes combined: poor diet, air/water pollution or overexposure to sun, alcohol, and old age. Slightly more than one half of students in kindergarten through sixth grade worried about getting cancer, and the vast majority (80%) knew that cancer could be fatal. Children have a less sophisticated conceptual understanding of cancer than of colds and a very limited factual knowledge base for cancer, and thus they have the capacity to increase both their understanding and knowledge. These results have implications for the creation of developmentally appropriate cancer prevention curricula for elementary school-age children.

Routine carotid endarterectomy without a shunt, even in the presence of a contralateral occlusion.

UNLABELLED: A 10-year prospective experience with routine non-shunting, even in the presence of a contralateral internal carotid artery occlusion, is reviewed. METHOD AND RESULTS: Carotid endarterectomy was performed without a shunt in 654 consecutive patients: group 1, 513 patients with contralateral stenosis of less than 79%: group 11, 74 patients with a greater than 80% contralateral stenosis; and group 111, 67 patients with a contralateral occlusion. Average cross-clamp time was 23 min. Neurological complications occurred within 30 days in 20 (3.0%) patients (10 strokes, seven transient ischemic attacks in group I, one transient ischemic attack in group II, and one stroke and one transient ischemic attack in group III). Immediate postoperative strokes, i.e. those five cases that could be implicated as caused by lack of a shunt, were rare (0.76%). There were five perioperative deaths (0.76%). CONCLUSION: Carotid endarterectomy may be performed safely without a shunt even in the presence of a contralateral occlusion. Age, sex, preoperative indication, anesthetic agent and contralateral stenosis were not associated with an increased risk of postoperative neurological deficit.

Is thigh saphenectomy a necessary adjunct to high ligation and stab avulsion phlebectomy?

BACKGROUND: Controversy still exists as to whether the thigh saphenous vein should be stripped concomitant with high ligation and phlebectomy. METHOD: A total of 218 procedures were retrospectively grouped into three groups: group 1, 10 limbs with visible, duplex scan-confirmed varicose veins of the thigh saphenous vein; group 2, 13 saphenous veins with varices that were not clinically evident; group 3, 195 limbs with incompetent saphenous veins without thigh saphenous varices. RESULTS: Five limbs in group 1 were treated by high ligation, phlebectomy, and thigh saphenectomy. All did well. Five had high ligation and phlebectomy only. Two developed painful phlebitis, and two had residual varices in the saphenous vein. Group 2 and group 3 were treated by high ligation and phlebectomy. One group 2 limb developed saphenous phlebitis. Five limbs in group 3 developed recurrent veins that were removed in the office. CONCLUSION: Thigh saphenectomy is only required when there are visible, duplex scan-confirmed varices of the thigh saphenous itself, or when the procedure is performed for severely symptomatic patients or those with advanced stasis changes.

A new method for assessing interexaminer agreement when multiple ratings are made on a single subject: applications to the assessment of neuropsychiatric symtomatology.

A new method is introduced for assessing levels of interexaminer agreement when multiple ratings are made on a single subject, with an application in psychiatric research. It is designed to provide an overall level of interexaminer agreement and separate indices of agreement for each examiner. These indices are based on biostatistical and clinical criteria to determine whether the ratings of any given examiner are appreciably higher or lower than the group average, or a consensus diagnosis. A number of examples, from ongoing psychiatric research, are provided to illustrate conditions favoring the application of the new methodology. Finally, the necessary software for performing the analyses is available to clinical investigators with interest in this area of assessment.

A computer program for assessing interexaminer agreement when multiple ratings are made on a single subject.

This report describes a computer program for applying a new statistical method for determining levels of agreement, or reliability, when multiple examiners evaluate a single subject. The statistics that are performed include the following: an overall level of agreement, expressed as a percentage, that takes into account all possible levels of partial agreement; the same statistical approach for deriving a separate level of agreement of every examiner with every other examiner; and tests of the extent to which a giver examiner's rating (say a symptom score of three on a five-category ordinal rating scale) deviates from the group or overall average rating. These deviation scores are interpreted as standard Z statistics. Finally, both statistical and clinical criteria are provided to evaluate levels of interexaminer agreement.

Children's understanding of the symptoms of AIDS.

Symptoms are the outward manifestations that allow children to identify and recognize illness; children's understanding of the symptoms of an illness may be directly related to their understanding of its cause or means of transmission. This study is the first empirical investigation of children's conceptual understanding and factual knowledge of the symptoms of AIDS. Children (N = 361; grades K to 6; 57% black, 24% Hispanic, 19% white; 52% female) attending four public schools in New Haven, Connecticut, were interviewed using a standardized semistructured interview (ASK, AIDS Survey for Kids) that included open-ended questions about the symptoms of AIDS and, for comparison, cancer and colds. Responses were scored for level of conceptual understanding and coded for factual content. For each illness, grade level was the variable most strongly correlated with symptomatology concept score (R = .42-.48, p < .0001) and contributed significantly (p < .0001) to the variance observed in concept score even after controlling for race, gender, verbal fluency, and socioeconomic status. The mean concept score was lower (p < .01) for symptomatology of AIDS (2.8 of possible 5) than for cancer (3.1) or colds (3.9). In addition, far more symptoms were named for colds than for either cancer or AIDS. Children who believed that HIV is spread via each of five potential means of transmission by casual contact were more likely (p < 01) to cite cold symptoms as symptoms of AIDS. We conclude that there exists a developmental progression in children's understanding of the symptomatology of AIDS. Children have a less sophisticated conceptual understanding and narrower factual knowledge base for AIDS than for colds and therefore have the capability to increase their understanding and knowledge about AIDS. Furthermore, improving children's understanding of the symptoms of AIDS may diminish misconceptions about transmission of HIV via casual contact.

Stockings and the prevention of recurrent venous ulcers.

BACKGROUND: Cost-effective therapy that heals ulcers rapidly and prevents recurrence would significantly impact patient care and the health system. OBJECTIVE: To evaluate compression stockings for treatment of venous ulcerations and prevention of recurrent ulceration; to analyze patient compliance; and to evaluate cost of compression stocking therapy. METHODS: Stocking therapy healed venous ulcers in 53 patients. The effect of continued stocking use on ulcer recurrence rate and treatment costs was evaluated. RESULTS: Twenty-five patients had good stocking usage; one developed recurrence (4%). Twenty-eight patients had bad or none usage; 22 had at least one recurrence (79%). Bad/none usage was associated with 31 of 32 (97%) recurrent ulcerations; good usage was associated with 52 of 58 (90%) nonrecurrent ulcers. Cost was a major reason for noncompliance. CONCLUSIONS: Continued stocking use after ulcer healing will prevent most recurrences and will provide a significant cost saving to the nation's health care budget.

Screening for lead poisoning by fingerstick in suburban pediatric practices.

OBJECTIVE: To assess the false-positive rate of blood lead determinations on samples obtained by fingerstick from children screened in private suburban and rural practices. METHODS: Screening capillary lead samples were obtained by fingerstick; children with capillary lead levels of 0.7 mumol/L (15 micrograms/dL) or greater were recalled for a confirmatory venous lead test that served as the criterion standard. Parents completed a five-question risk assessment questionnaire at the time of initial screening. SETTING: Four private suburban to rural practices that serve predominantly white, middle-class populations. PARTICIPANTS: Children seen for routine care between August 1992 and February 1993 (N = 1085; 98% between 6 months and 6 years of age). RESULTS: Capillary lead level was 0.7 mumol/L (15 micrograms/dL) or greater in 35 children (3% of total sample); venous lead samples were obtained in 30 patients. Nine of the elevated capillary lead results were true-positives (venous lead = 0.7, 0.8, 0.8, 0.9, 0.9, 0.9, 1.1, 1.1, and 1.7 mumol/L [15, 17, 17, 18, 18, 18, 22, 22, and 35 micrograms/dL]); parents of only two of these children answered yes to any question on the risk assessment questionnaire. Although the false-positive rate of the capillary lead screening test was 70% (21/30) in this setting, only 2% of the total sample had a false-positive screening test (an average of fewer than one false-positive per month per practice). Screening by fingerstick allowed phlebotomy to be avoided for 97% of the children. CONCLUSION: Fingerstick screening for lead poisoning is a reasonable alternative to direct venous testing within private suburban and rural practices, provided that care is taken to avoid specimen contamination, that appropriate caution is used in the interpretation of screening test results, and that medical and environmental interventions are based on the results of confirmatory venous testing.

A randomized, controlled trial of a school-based, multi-faceted AIDS education program in the elementary grades: the impact on comprehension, knowledge and fears.

OBJECTIVE: Several educational theorists have suggested that young children are unlikely to benefit from detailed instruction regarding AIDS prevention because of inherent developmental cognitive limitations. This study aims to determine whether AIDS education in the elementary grades can advance young children's understanding of this illness. METHODS: A randomized, controlled trial was used to measure the impact of a 3-week, multifaceted AIDS education program on conceptual understanding, factual knowledge, and fears about AIDS in 189 students in grades kindergarten through 6th. The ASK (AIDS Survey for Kids), a standardized, semistructured interview that measures conceptual understanding, factual information, and fears about AIDS, was administered before and after the intervention. RESULTS: Children in the intervention group, as compared to those in the control group, showed significant (P < .0001) gains in their level of understanding of the concepts of causality and prevention of AIDS. These results were unaffected by controlling for grade, gender, race, socioeconomic status, and verbal fluency. The gains in children's understanding of causality of AIDS represented at least 2 years' growth in the level of conceptual sophistication and persisted at a follow-up evaluation several months later. After the intervention, more children (P < .001) in the intervention group than in the control group accurately identified causes of AIDS in response to open-ended questions: germ/germ theory (41% vs 13%), mother-to-infant transmission (54% vs 15%), blood transmission (83% vs 40%), and sexual transmission (56% vs 30%). Fewer than half as many children in the intervention group responded incorrectly to each of five direct questions about transmission of HIV through casual contact. The intervention did not increase children's fears about the illness. CONCLUSIONS: A short, developmentally based, multifaceted AIDS education program in the elementary grades can advance children's conceptual understanding and factual knowledge about AIDS and decrease their misconceptions about casual contact as a means of acquiring the illness, without increasing their fears. Significant advances in conceptual understanding about AIDS can be achieved through direct educational interventions.

Laparotomy for fulminant pseudomembranous colitis.

Clostridium difficile-associated pseudomembranous colitis is an increasingly common nosocomial infection that usually responds to oral antibiotics. Presentation as an acute abdomen occurred in 12 patients, leading to 14 laparotomies. A distinctive clinical picture was observed: advanced age, recent treatment with antibiotics, fever, abdominal pain, tenderness, marked leukocytosis, and ileus. Only six of the 12 patients had diarrhea. Five were immunosuppressed. Abdominal computed tomographic scans revealed ascites and a massively thickened colonic wall. All four patients treated by subtotal colectomy survived. Four of 10 patients treated only with laparotomy or segmental colectomy died, four responded to medical therapy, and the conditions of two deteriorated but were salvaged by subtotal colectomy. Early diagnosis via endoscopy or computed tomography should obviate the need for exploratory operations. However, progressive toxic effects indicate failure of medical therapy and the need for subtotal colectomy.

Biomechanics of the venous wall under simulated arterial conditions.

The failure of vein graft conduits implanted in the arterial circulation has been hypothesized to occur in part due to the exposure of the graft to altered biomechanical and fluid shearing forces. In the present study, these forces are characterized for canine internal jugular veins (IJV) exposed to realistic arterial flow dynamics. Freshly excised vein segments were mounted into a pulsatile perfusion apparatus and exposed to arterial flow conditions (P = 115/75 mmHg and Q = 110 ml min-1) for 2 h. Dynamic measurements of intraluminal pressure and flow rate and vessel wall radial distension were acquired to accurately quantitate the incremental modulus of elasticity; hoop, axial and radial wall stresses; and fluid shearing forces within the vessel. Identical measurements were performed on canine carotid arteries (CCA) to serve as a comparison. Under arterial conditions, IJV segments demonstrated a significant elevation (p less than 0.05) over the CCA in the incremental elasticity modulus, along with a corresponding elevation in hoop and axial wall stresses. Additionally the average wall shearing rate to which the IJV endothelial surface was exposed was a factor of six less than that observed in the CCA. These results are discussed in relationship to the clinical situation of vein graft adaptation to arterial hemodynamics.

Cryopreserved venous homografts as vascular conduits in canine carotid arteries.

In this study we evaluated the histologic condition, prostacyclin production, and compliance of morphologically intact cryopreserved venous homografts (CVH) and autografts 3, 6, and 9 months after arterial implantation. Eighteen external jugular veins were cryopreserved and implanted into the carotid arteries of mongrel dogs. All grafts were patent at the time of excision. Electron microscopy documented a disrupted endothelium in the homografts at 3 months that was intact at 9 months. The cellular infiltrate, suggestive of rejection, in the 3-month homografts resolved by 9 months. Prostacyclin production at 3 months was 8.7 +/- 3.2 pg/ml/cm2 compared with 24.1 +/- 9.6 pg/ml/cm2 (p less than 0.025) in the adjacent carotid artery. The prostacyclin production in the 6-month homografts was 21.7 +/- 12.4 pg/ml/cm2, not significantly different from the adjacent carotid artery. The return of prostacyclin paralleled the return of an intact endothelium. Compliance of fresh vein was diminished by cryopreservation, from 1.57 +/- 0.39% radial change/mm Hg (10(-2] to 0.79 +/- 0.21% radial change/mg Hg (10(-2] (p less than 0.02). The compliance of CVH at 3 months (1.7 +/- 1.0) and at 6 months (1.1 +/- 0.42) was not significantly different from cryopreserved veins. These data showed that CVH remained patent in dogs for 9 months, without loss of compliance for 6 months, and developed a morphologically intact and functional endothelium that paralleled the resolution of the inflammatory infiltrate.

Hemodynamic effects on endothelial cell monolayer detachment from vascular prostheses.

The establishment of an early blood-contacting endothelialized surface may improve the graft-host relationship. This study evaluated the adherence of indium 111-radiolabeled endothelial cells that were cultured to confluence on fibronectin-treated polyester elastomer (Hytrel) grafts that were perfused for two hours on a pulse duplicator apparatus under high- and low-shear conditions. Perfusate samples were serially assayed for radioactivity. After perfusion, grafts were sectioned into four segments and assayed for retained radioactivity. All graft segments were hematoxylin stained and examined under light microscopy for evaluation of cell density. Excellent endothelial cell adherence (90%) was observed under both hemodynamic conditions at 120 minutes, with most losses occurring within the first 15 minutes. No differences were seen between high- and low-shear conditions or proximal vs distal graft segments.

Comparative pharmacokinetics of chlortetracycline in milk-fed versus conventionally fed calves.

Plasma and tissue concentration and pharmacokinetics of chlortetracycline (CTC) was determined in milk-fed and conventionally fed Holstein calves. A two-compartment open model was used after a single intravenous dose (11 mg CTC/kg body weight). There were no significant differences between dietary treatments. The drug was rapidly distributed from plasma into the peripheral compartment but was slowly eliminated, with detectable concentration of CTC continuing for 72 h after dosing. A single-compartment model was used after a single oral dose (22 mg CTC/kg body weight). All but four of the kinetic parameters were significantly different for the two dietary treatments. Milk-fed calves had a larger area under the plasma level curve, a larger fraction of the dose absorbed, a smaller volume of distribution and a smaller overall body clearance rate. Estimated recovery of CTC in the urine of the milk-fed calves was greater, regardless of route of administration. The concentration of CTC in tissues following an oral dose was greatest in kidney, followed by liver, heart, skeletal muscle, spleen and brain. Tissue depletion of CTC closely paralleled the decline in plasma concentration.