Strengths and limitations of Bacillus thuringiensis galleriae for managing Japanese beetle (Popillia japonica) adults and grubs with caveats for cross-order activity to monarch butterfly (Danaus plexippus) larvae

BACKGROUND

Target-selective biopesticides are needed to facilitate integrated pest and pollinator management in urban landscapes and gardens. Bacillus thuringiensis galleriae, strain SDS-502 (Btg), recently registered in the USA and Canada, produces Cry8Da protein active against scarab beetles. We evaluated Btg formulations for managing the Japanese beetle [Popillia japonica Newman (JB)], a polyphagous invasive pest, including residual spray effectiveness for reducing adult feeding on Rosa and Tilia spp., and granular formulations for early- or late-curative control of root-feeding grubs in turfgrass. We also tested for cross-order activity to monarch butterfly (Danaus plexippus L.) larvae and other non-target insects.

RESULTS

Field-weathered Btg residues reduced JB feeding on foliage for 3-14 days. Most beetles were still flight-capable after 24 h confinement with Btg-treated leaves. Granular Btg failed to control early- or late-instar JB grubs in soils under several turfgrass species at multiple field sites. In three trials, feeding on Btg-sprayed milkweed resulted in 97-100% mortality of early instar monarchs, with symptoms of B. thuringiensis pathogenesis. Fall armyworms (Spodoptera frugiperda (J.E. Smith)) fed Btg-treated grass had reduced body mass, but there were no adverse effects on lady beetle larvae preying on Btg-sprayed aphids or on the aphids themselves.

CONCLUSION

This study supports efficacy of Btg strain SDS-502 for reducing defoliation by adult JB in urban landscape settings. Granular formulations, however, failed to control JB grubs in turfgrass soils. Btg should not be used in gardens with larval host plants of the monarch butterfly or other non-pest Lepidoptera, especially species of conservation concern. © 2019 Society of Chemical Industry.

Fungicides affect Japanese beetle Popillia japonica (Coleoptera: Scarabaeidae) egg hatch, larval survival and detoxification enzymes

BACKGROUND

Larvae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), have a patchy distribution in soils, which complicates detection and management of this insect pest. Managed turf systems are frequently under pest pressure from fungal pathogens, necessitating frequent fungicide applications. It is possible that certain turfgrass fungicides may have lethal or sublethal adverse effects on eggs and larvae of P. japonica that inhabit managed turf systems. In this study, eggs and first-, second- and third-instar larvae were treated with the fungicides chlorothalonil and propiconazole, and survival was compared with that of untreated controls as well as positive controls treated with the insecticide trichlorfon.

RESULTS

Chlorothalonil reduced survival of first-instar larvae treated directly and hatched from treated eggs. Propiconazole delayed egg hatch, reduced the proportion of eggs that successfully hatched and reduced survival of first-instar larvae treated directly and hatched from treated eggs. Sublethal doses of the fungicides lowered the activities of certain detoxification enzymes in third-instar grubs.

CONCLUSIONS

Fungicide applications to turfgrass that coincide with oviposition and egg hatch of white grubs may have sublethal effects. This work is applicable both to high-maintenance turfgrass such as golf courses, where applications of pesticides are more frequent, and to home lawn services, where mixtures of multiple pesticides are commonly used.

Suitability of Creeping Bentgrass and Bermudagrass Cultivars for Black Cutworms and Fall Armyworms (Lepidoptera: Noctuidae)

The black cutworm, Agrotis ipsilon Hufnagel, and fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), are common turfgrass pests of golf courses in the southeastern United States. Heat-tolerant bentgrass (Agrostis stolonifera L.) cultivars are expanding the range of bentgrass further south, but these cultivars have not been studied for their potential host plant resistance to black cutworm or fall armyworm. The goals of the study were to investigate feeding response of black cutworm and fall armyworm to these newer heat-tolerant creeping bentgrass cultivars, as well as commonly used cultivars of bermudagrass [Cynodon dactylon (Loppers.)]. Choice and no-choice feeding assays and fecundity tests were conducted in the laboratory and greenhouse to evaluate performance and preference of the two insects. When given a choice, neither black cutworm nor fall armyworm showed a preference for the majority of new cultivars tested. There were no differences in leaf area consumption or insect development for either pest in no-choice feeding assays. Black cutworm females preferred laying eggs in bentgrass compared with bermudagrass, but will oviposit onto bermudagrass, suggesting that both turf species are suitable hosts of this pest. The broad host ranges of generalist caterpillar pests of turfgrass hinder the application of host plant resistance in integrated pest management on golf courses.

Evaluation of chemical controls and entomopathogenic nematodes for control of Phyllophaga white grubs in a Fraser fir production field

The results of 2 yr of field trials evaluating various chemical and biological controls of Phyllophaga anxia (LeConte) white grubs in a Fraser fir [Abies fraseri (Pursh) Poir] Christmas tree production field are reported here. Chemical insecticides evaluated included bifenthrin, chlorantraniliprole, thiamethoxam, and time-released imidacloprid tablets (Coretect, Bayer CropScience, Research Triangle Park, NC). Entomopathogenic nematodes evaluated included Heterorhabditis bacteriophora (Poinar) and Steinernema carpocapsae (Weiser). Overall, the chemical controls provided the best root protection and grub control. Targeted treatments of an insecticide in the root zone may provide adequate tree protection and can be a way to reduce overall insecticide input compared with banded sprays. The nematode H. bacteriophora provided limited root protection and grub control, whereas S. carpocapsae did not provide effective control. Differences in efficacy and persistence of the two entomopathogenic nematode species can be attributed to the biology and environmental preferences of these organisms.

Potential management strategies for the linden borer (Coleoptera: Cerambycidae) in urban landscapes and nurseries

The linden borer, Saperda vestita Say (Coleoptera: Cerambycidae), is a native insect species that is common throughout north central and northeastern North America. Over the past decade, increasing occurrence of damage associated with the linden borer has been reported on Tilia spp. in city street trees and nurseries throughout Wisconsin, probably because of increased use of these trees. Our objective was to gain a better understanding of the seasonal biology and potential management strategies for this important pest. We evaluated the effectiveness of three systemic insecticides, imidacloprid, thiamethoxam, and disulfoton, and a mechanical control method of chipping linden borer-infested wood as a means of reducing S. vestita larval survival, subsequent emergence, and oviposition. Autumn and spring soil injections of imidacloprid to linden borer-infested Tilia cordata'Greenspire' nursery stock (< 11.4 cm in diameter at breast height [dbh]) provided >90% control. Autumn soil injections of imidacloprid and thiamethoxam and a spring granular soil application treatment of disulfoton applied to larger (>22 cm dbh) Tilia spp. did not effectively control linden borer at the application rates tested. Chipping infested Tilia spp. effectively destroyed linden borer larvae, pupae, and adults. Arborists and landscape managers should consider chipping felled Tilia spp. trees infested with S. vestita to prevent adults from potentially attacking nearby susceptible trees.

Suitability of various turfgrass species and cultivars for development and survival of black cutworm (Lepidoptera: Noctuidae)

Black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), feeding bioassays were conducted on young and mature turfgrass species to determine their potential resistance. Measures of resistance included larval weight, survival rate, instar development, pupal weight, duration of pupation, and days to pupation and adult emergence. Black cutworm reared on Poa pratensis 'Midnight', Poa arachnigera 'Tejas', and Poa pratensis X Poa arachnigera 'Reveille' exhibited slower development, lower weight, and higher overall mortality than those fed upon other turfgrasses tested. Larvae reared on Reveille did not survive to pupation and all died within 14 d. Black cutworm larvae reared on Midnight died within 17 d in trial 1 but attained pupation in trial 2. However, development of black cutworm larvae was slower on Poa pratensis Midnight compared with other susceptible turfgrass species such as Agrostis stolonifera 'Penncross', Poa annua ('DW194', 'Q98-4-6', and 'Q98-6-18'), Lolium perenne, and Poa supina 'Supranova'. Generally, larval performance on young plant tissues was better than on mature plant tissues. Larvae reared on P. pratensis 'Midnight' exhibited the most distinctive difference on young versus mature plant tissue. These results suggest that plant age may play an important role in turfgrass susceptibility and resistance.

Trapping Phyllophaga spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants

The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester.

Trapping Phyllophaga spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants

The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester.

Evaluation of a nonconventional insecticide and appropriate application timing for destruction of gypsy moth (Lepidoptera: Lymantriidae) egg masses

Two field studies were conducted in 2001-2002 and 2003 to evaluate the effectiveness and appropriate application timing of Golden Pest Spray Oil (GPSO) for destruction of gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), egg masses in Wisconsin. GPSO is a commercially available, registered pesticide that is predominantly comprised of a soybean-oil base (93%); its primary mode of action is by means of suffocation. Because gypsy moth spends the majority (>75%) of its life cycle in the egg stage (August-April), the potential utility of this product by arborists, city foresters, landscapers, and homeowners is high, especially because GPSO is a United States Environmental Protection Agency registered, nonconventional pesticide that is considered relatively nontoxic. When GPSO was applied at a 1:1 ratio with water, >96% control of gypsy moth egg masses was achieved, regardless of application timing (October, 3 d before egg hatch).

Comparison of sticky wing and cone pheromone traps for monitoring seasonal abundance of black cutworm adults and larvae on golf courses

Black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), flight activity was monitored on three golf courses in Wisconsin by using two types of pheromone traps: the Texas cone trap and sticky wing trap. The Texas cone trap caught significantly more black cutworm males compared with the sticky wing trap, capturing almost 12-fold more males. Black cutworm males were most abundant during mid-July in 2001 and 2002, between 700 and 800 cumulative degree-days. Flight activity also was detected in early May and mid-August, but these peaks were not as pronounced as in mid-July. No definitive relationship between black cutworm flight activity and subsequent larval infestations on golf course putting greens occurred.

How to write a review article

Writing a good review article is a real challenge. It requires not just a detailed literature search but a thorough 'digest' of the material obtained. Readers seek an up-to-date guide through a morass of data that has been sifted by the author and then integrated into a coherent and authoritative account.

Expression of inducible nitric oxide synthase contributes to the development of pancreatitis following pancreatic ischaemia and reperfusion

BACKGROUND

Inducible nitric oxide synthase (iNOS) activity is increased in experimentally induced acute pancreatitis. Increased expression of this isoform of nitric oxide synthase has been demonstrated in several organs subjected to ischaemia-reperfusion injury. The present experiment investigated the expression of iNOS and the effect of selective iNOS inhibition in pancreatic ischaemia-reperfusion.

METHODS

Wistar rats (n = 40) were randomly and equally assigned to four groups. Groups 2 and 4 underwent 60 min of total pancreatic ischaemia followed by 6 h of reperfusion (I-R). Groups 1 and 3 underwent sham operation. The selective iNOS inhibitor L-N(6)-(1-iminoethyl)-lysine (L-NIL) was administered to groups 3 and 4. Expression of iNOS was examined by immunohistochemistry. Other investigations included measurement of serum amylase activity and pancreatic wet : dry weight ratio, and histopathological examination.

RESULTS

Eight of ten rats in group 2 (I-R only) expressed iNOS but none of the ten animals in group 1 (sham laparotomy) did so. Group 4 (I-R + L-NIL) animals had significantly lower serum amylase levels and wet : dry weight ratios than those in group 2 (I-R only). Microscopic evidence of pancreatic injury was present only in rats in group 2 (I-R only).

CONCLUSION

Expression of iNOS during reperfusion following pancreatic ischaemia contributes significantly to the development of acute pancreatitis.

Sensitivity-bandwidth product for electro-optic modulators

For lumped-element electro-optic modulators, the sensitivity ( partial differentialphi/ partial differentialV) of the phase, phi , in response to an applied voltage V is related to the optical group delay, T(g) , and the bandwidth, Domega . This relationship imposes a fundamental trade-off between the sensitivity and the bandwidth of electro-optic modulators: ( partial differentialphi/ partial differentialV)Domega= (dn/dV)(omega /n) , where n is the optical index. A similar relationship for traveling-wave modulators sets an upper limit on ( partial differentialphi/ partial differentialV) that is proportional to T(g) .

Estimating the support of a high-dimensional distribution

Suppose you are given some data set drawn from an underlying probability distribution P and you want to estimate a "simple" subset S of input space such that the probability that a test point drawn from P lies outside of S equals some a priori specified value between 0 and 1. We propose a method to approach this problem by trying to estimate a function f that is positive on S and negative on the complement. The functional form of f is given by a kernel expansion in terms of a potentially small subset of the training data; it is regularized by controlling the length of the weight vector in an associated feature space. The expansion coefficients are found by solving a quadratic programming problem, which we do by carrying out sequential optimization over pairs of input patterns. We also provide a theoretical analysis of the statistical performance of our algorithm. The algorithm is a natural extension of the support vector algorithm to the case of unlabeled data.

The effect of N(G)-monomethyl-L-arginine and tamoxifen on nitric oxide production in breast cancer cells stimulated by oestrogen and progesterone

OBJECTIVE

To examine the capacity of oestrogen, or progesterone, or both to elicit the release of nitric oxide (NO) from T47D breast cancer cells in vitro.

DESIGN

Prospective, longitudinal, controlled in vitro experiment.

SETTING

University Medical School, United Kingdom. MATERIAL AND INTERVENTIONS: T47D breast cancer cells were stimulated by micromolar to picomolar doses of 17beta-oestradiol, or progesterone, or both, with or without inhibition of NO or tamoxifen at 24 and 48 hours.

MAIN OUTCOME MEASURES

Concentration of NO metabolites (nitrite + nitrate) in the culture medium measured by chemiluminescence.

RESULTS

Both hormones dose-dependently increased the proliferation of T47D without toxic effects over the range 10(-12)-10(-6) M. Both stimulated NO production at 24 hours, micomolar doses producing a pronounced (2-4 fold) increase in the concentration of NO metabolites in culture medium (p = 0.002 and p < 0.001 for oestradiol and progesterone, respectively). By contrast, incubation with hormones for 48 hours had little effect on the concentrations of NO metabolites. NO production induced by hormones was completely inhibited by the NO synthesis inhibitor N(G)-monomethyl-L-arginine (10(-5)-10(-3) M) and by tamoxifen (10(-8)-10(-4) M) (p < 0.001 in each case).

CONCLUSIONS

Oestrogen and progesterone have a role in stimulating NO production in T47D breast cancer cells. Inhibition of NO synthesis might be a novel therapeutic approach for reducing hormone-associated angiogenesis in breast cancer.

Genomic homogeneity in fibrolamellar carcinomas

BACKGROUND

Fibrolamellar carcinoma (FLC) is a variant of hepatocellular carcinoma (HCC) with distinctive clinical and histological features. To date there have been few studies on the genotypic aspects of FLC and no previous attempts have been made to use the arbitrarily primed-polymerase chain reaction (AP-PCR) technique to detect genetic alterations in this disease.

AIM

The aim of this study was to assess the degree of genomic heterogeneity of FLC using the AP-PCR technique.

METHODS

A total of 50 tissue samples of primary and metastatic FLCs from seven patients were microdissected. AP-PCR amplification of each genomic DNA sample was carried out using two arbitrary primers.

RESULTS

DNA fingerprints of the primary FLCs and all their metastatic lesions (both synchronous and metachronous disease) were identical in an individual patient. The fingerprints were different between tumours of different patients. No evidence of intratumour heterogeneity was observed.

CONCLUSIONS

Such genomic homogeneity in FLCs may explain their indolent growth. The absence of clonal evolution, which is present in other tumours (particularly HCCs), may explain the distinct behaviour in this tumour. The tumorigenic pathway and degree of somatic genomic changes in this disease may be less complex than in HCC.

Measurement of mode-locked laser timing jitter by use of phase-encoded optical sampling

The phase-noise characteristics of a harmonically mode-locked fiber laser are investigated with a new measurement technique called phase-encoded optical sampling. A polarization-maintaining ring laser is mode locked by use of the short-pulse electrical output of a resonant-tunneling diode oscillator, enabling it to produce 30-ps pulses at a 208-MHz repetition rate. The interferometric phase-encoded sampling technique provides 60-dB suppression of amplitude-jitter noise and allows supermode phase noise to be observed and quantified. The white-noise pulse-to-pulse timing jitter and the rms supermode timing jitter of the laser are measured to be less than 50 and 70 fs, respectively.

Achieving eugastrinaemia in Zollinger-Ellison syndrome: resection or enucleation?

BACKGROUND

Eugastrinaemia in Zollinger-Ellison syndrome can be an elusive goal, nearly one third of laparotomies failing to detect the tumour.

METHODS

A personal series of 13 patients with a mean age of 52 years operated between 1980 and 1996 was reviewed retrospectively. All patients had fasting hypergastrinaemia and recalcitrant ulcer disease with or without diarrhoea.

RESULTS

Computed tomography or selective visceral angiography localised the tumour to the pancreas in 6 of 12 elective patients; the thirteenth presented with a perforated duodenal ulcer. All underwent laparotomy with gastrinoma tissue being completely excised in every case, including the 6 patients with failed pre-operative localisation whose tumours arose from the duodenum (4), pancreas (1) and lymph node (1). Eugastrinaemia was achieved in all but 1 patient and was sustained during a mean follow-up of 5.2 years (SD = 4.2 years). These 12 patients remained clinically free of disease during a mean clinical follow-up of 7.5 years (SD = 5.0 years; range 2-19 years). There were no postoperative deaths, but 3 died from recurrent tumour at 3-7 years.

CONCLUSION

Since normalisation of serum gastrin was achieved in 12 of 13 patients, laparotomy may well be worthwhile even if the gastrinoma cannot be localised pre-opera- tively.

Magnesium deficiency in patients with chronic pancreatitis identified by an intravenous loading test

Magnesium deficiency is a common clinical condition that may exist despite a normal serum magnesium concentration. Patients with chronic pancreatitis could develop magnesium deficiency due to either malabsorption, diabetes mellitus, or chronic alcoholism. Since serum levels of magnesium are a poor indicator of magnesium deficiency, the retention of a low-dose intravenous magnesium load (0.1 mmol/kg body weight) was determined in 13 patients with chronic pancreatitis (10 due to alcoholism) and eight healthy controls. Percentage magnesium retention was greater in patients with chronic pancreatitis than controls (59.8+/-37.3% S.D. versus 22.0+/-38.2% S. D.: P=0.038), and 10 of 13 patients showed evidence of magnesium deficiency. Routine evaluation of magnesium status could allow appropriate supplementation and conceivably symptomatic improvement in patients with severe chronic pancreatitis.

Operative treatment of pseudocysts in patients with chronic pancreatitis

BACKGROUND

Pseudocysts associated with chronic pancreatitis are generally intrapancreatic and associated with parenchymal disease. They tend to persist and cause complications. Minimally invasive methods of treatment challenge the traditional techniques of operative management. Surgical operation allows definitive treatment of the pseudocyst with the option of dealing appropriately with the diseased pancreas and excluding a neoplastic process. The aim of this study was to review the safety and efficacy of a surgical approach to the management of pseudocysts associated with chronic pancreatitis.

METHODS

A personal series of 112 consecutive patients operated for pseudocysts in the setting of chronic pancreatitis was reviewed. Chronic pancreatitis was confirmed by imaging studies in association with exocrine and/or endocrine failure. Cysts were multiple in 31 patients and presented with complications other than pain in 47. Data were collected prospectively regarding the clinical presentation, the nature of the operation and its outcome.

RESULTS

Forty-eight patients (43 per cent) underwent drainage procedures, 56 (50 per cent) had a resection and eight (7 per cent) had a combination. Larger cysts and those located in the head and neck tended to be drained, while smaller and distal cysts were more often resected. The morbidity rate was 28 per cent and the operative mortality rate was 1 per cent. The cyst recurrence rate was 3 per cent and pain was relieved in 74 per cent of patients.

CONCLUSION

Operative management of pseudocysts associated with chronic pancreatitis is effective with low morbidity and mortality rates. The introduction of newer minimally invasive techniques will have to withstand comparison to this traditional approach.

Thromboprophylaxis in the cancer patient

Thrombosis is a common complication in patients with malignant disease resulting from tumour elaboration of procoagulants and subsequent activation of intravascular coagulation. Cancer therapies (operation, chemotherapy and the use of central venous lines) further heighten the risk of thrombosis. The risk of thrombosis in cancer operations is of sufficient magnitude to necessitate routine thromboprophylaxis, for which low-dose unfractionated heparin or the low-molecular-weight heparins (LMWHs) have been proven effective and safe. Thrombotic complications with chemotherapy have been extensively described in women receiving either adjuvant or palliative cytotoxic or hormonal therapy for breast carcinoma. The problems are common, but of all the suitable prophylactic modalities available, only oral anticoagulants have been evaluated for this indication. Thrombosis complicates the use of central venous catheters in the cancer patient and both low-dose warfarin and LMWHs are effective in protecting against line-associated thrombi. Recent evidence from the retrospective analyses of randomized studies comparing unfractionated heparin and LMWH in the treatment of deep vein thrombosis have shown a striking mortality reduction among cancer patients who received LMWH. The use of LMWHs to prolong survival in patients with advanced malignant disease is currently the subject of a prospective, randomized, placebo-controlled study.

Nitric oxide induction in a rat model of selective pancreatic ischemia and reperfusion

BACKGROUND/AIMS

Ischemia and reperfusion of the pancreas may be important in aggravating the course of acute pancreatitis. In a rat model of selective pancreatic ischemia and reperfusion, we studied plasma levels of nitric oxide and expression of nitric oxide synthase in the pancrease and lung.

METHODOLOGY

Pancreatic ischemia was achieved by occlusion of the 4 main pancreatic arteries for 40 min; this was followed by a 7-hour reperfusion period (group A, 10 rats). Outcome measures were compared with those of animals undergoing a sham operation (group B, 10 rats).

RESULTS

Pancreatic damage in group A animals was demonstrated by increased serum alpha-amylase and by macroscopic and microscopic evidence. Total nitric oxide synthase activity in pancrease and lung was higher than in shams [median: 0.73 vs. 0.54 pmol/mg protein/min in the pancreas (P = 0.0082); 1.38 vs. 0.68 pmol/mg protein/min in the lung (P = 0.023)]; this was mainly due to activation of the inducible isoform of the enzyme. There was an associated 58.2% increase in plasma levels of nitric oxide metabolites [from mean 55.0 to 131.6 mumol/L (P < 0.001)]. Immunohistochemistry confirmed expression of inducible nitric oxide synthase and nitric oxide-mediated oxidative damage (nitrotyrosine) in both pancreas and lung.

CONCLUSIONS

Ischemia and reperfusion of the pancreas induces pancreatic damage, overexpression of inducible nitric oxide synthase and oxidative damage within the pancreas and lung.

A continuing role for surgical bypass in the palliative treatment of pancreatic carcinoma

BACKGROUND

The use of palliative surgery for irresectable pancreatic cancer has been challenged by the advent of non-operative stenting, but it may still be appropriate for selected patients.

METHODS

Single-loop biliary and gastric bypass was carried out in 56 patients (mean age 60 years) with carcinomas of the pancreatic head that were irresectable because of vascular invasion or distant spread. In 42 patients without a preoperative tissue diagnosis, ductal carcinoma was confirmed by biopsy of the primary (n = 20) or secondary (n = 22) tumour. Preoperative biliary decompression in 31 patients led to positive bile cultures in 22 of 24 patients sampled.

RESULTS

There were no deaths in hospital or within 30 days. Complications in 20 patients (35%) included three biliary leaks, two of which required temporary percutaneous stents. The median postoperative hospital stay was 14 days. No re-operations were required before death, though 2 patients required percutaneous stenting of the biliary anastomosis for recurrent jaundice, 1 of whom had a radiation-induced stricture. The median survival was 6 (range 2-21) months.

CONCLUSION

Combined biliary and gastric bypass can be carried out with reasonable safety and remains a useful option for patients with potentially resectable tumours and an anticipated life expectancy of at least 6 months.

Collagen variation during experimental acute obstruction of the left colon

BACKGROUND/AIMS

The colonic response to obstruction is poorly understood. Thickening of the proximal bowel following colonic stricture may be due to increased protein synthesis. We have investigated the colonic morphology and collagen concentration during the development of left-sided colonic obstruction in an animal model.

METHODS

Twelve male Wistar rats received either a silk ligature obstruction of the colon 2.5 cm above the peritoneal reflection (n = 6) or manipulation of the left colon (controls, n = 6). Twenty-four hours later, three colonic specimens from the ligature zone and from 1 cm proximal and distal to this site, or from equivalent regions in controls, were assayed for hydroxyproline concentration.

RESULTS

In controls there was no difference in hydroxyproline concentration between colonic sites. In obstructed rats, the hydroxyproline concentration was greater both at the ligature and distally, when compared with the proximal region. The hydroxyproline concentration was higher (p < 0.05) than corresponding control values at the ligature site (14.95 +/- 2.76 vs. 10.97 +/- 1.95 microgram/mg of dry tissue mean +/- s.d.) but not on either side.

CONCLUSION

The colonic collagen concentration is equivalent or raised near an obstruction, demonstrating that obstructed colon may possess an enhanced capacity to hold sutures.

New support vector algorithms

We propose a new class of support vector algorithms for regression and classification. In these algorithms, a parameter nu lets one effectively control the number of support vectors. While this can be useful in its own right, the parameterization has the additional benefit of enabling us to eliminate one of the other free parameters of the algorithm: the accuracy parameter epsilon in the regression case, and the regularization constant C in the classification case. We describe the algorithms, give some theoretical results concerning the meaning and the choice of nu, and report experimental results.

Nearfield broadband array design using a radially invariant modal expansion

This paper introduces an efficient parameterization for the nearfield broadband beamforming problem with a single parameter to focus the beamformer to a desired operating radius and another set of parameters to control the actual broadband beampattern shape. The parameterization is based on an orthogonal basis set of elementary beampatterns by which an arbitrary beampattern can be constructed. A set of elementary beamformers are then designed for each elementary beampattern and the desired beamformer is constructed by summing the elementary beamformers with frequency and source-array distance dependent weights. An important consequence of our result is that the beamformer can be factored into three levels of filtering: (i) beampattern independent elementary beamformers; (ii) beampattern shape dependent filters; and (iii) radial focusing filters where a single parameter can be adjusted to focus the array to a desired radial distance from the array origin. As an illustration the method is applied to the problem of producing a practical array design that achieves a frequency invariant beampattern over the frequency range of 1:10 (which is suitable for speech acquisition using a microphone array), and with the array focused either to farfield or nearfield where at the lowest frequency the radial distance to the source is only three wavelengths.

Genomic heterogeneity in synchronous hepatocellular carcinomas

BACKGROUND

Hepatocellular carcinoma (HCC) arising in cirrhosis is frequently multifocal. Whether HCC develops monoclonally or multiclonally is an unresolved question. Of the multiple tumour nodules present in many patients, it has not been established whether the smaller lesions represent intrahepatic metastases or de novo cancers.

AIMS

To assess the degree of genomic heterogeneity in synchronous HCCs in cirrhosis.

METHODS

The arbitrarily primed polymerase chain reaction technique was utilised to compare the DNA fingerprint of HCCs and regenerative nodules (RNs) removed from cirrhotic explant livers.

RESULTS

Polymorphic genomic heterogeneity was noted in 54 HCCs and 31 RNs microdissected. Even satellite nodules in close proximity within the same segment of the liver were found to have distinct genomic patterns.

CONCLUSION

Such genomic heterogeneity in synchronous HCCs may explain poor patient survival after surgical resection. If the smaller tumours are de novo lesions rather than metastases (as these data suggest), then current concepts regarding liver resection as a curative treatment modality for HCC may require reassessment.

Evolution of genetic abnormalities in hepatocellular carcinomas demonstrated by DNA fingerprinting

Hepatocellular carcinomas (HCC) often contain subpopulations of cells showing heterogeneous differentiation within each tumour. The majority of HCCs first appear as well-differentiated lesions and proliferate with gradual dedifferentiation. The present study was designed to investigate the clonal diversity which is seen with progression in neoplasms. The degree of genomic heterogeneity of HCC nodules was assessed using the arbitrarily primed-polymerase chain reaction technique. Two or more sectors of 31 HCC nodules were needle-microdissected and amplified with two different arbitrary primers in appropriate conditions. In every HCC less than 6 mm in diameter (n=18, range 3-6 mm, mean diameter 4.7 mm), all sectors of each of these lesions had the same DNA fingerprint. All HCC nodules greater than 6 mm diameter (n=13, range 7-30 mm, mean diameter 15.4 mm) showed distinct DNA fingerprints in each sector sampled (p< 0. 05, compared with size less than 6 mm in diameter). When synchronous HCCs were present, no two tumour nodules had the same DNA fingerprint. These results suggest that a process of clonal evolution occurs in expanding HCC, with neoplasms more than 6 mm in diameter developing as multiple clones. The advent of laser capture microdissection technology makes such analysis much more rapid and easily applied. Studies of clonality in HCCs, including borderline cases, are made possible by the combination of these novel techniques.

Role of tissue factor expression on tumour cell invasion and growth of experimental pancreatic adenocarcinoma

BACKGROUND

Tissue factor (TF), the physiological procoagulant, is expressed in pancreatic tissue as a result of malignant transformation. The aim of this investigation was to assess its role in pancreatic tumour cell invasion and primary tumour growth.

METHODS

The full-length TF gene (1360 base pairs) was cloned into the plasmid DNA vector pcDNA3 in sense and antisense orientations, and these vectors were used to transfect the MIA PaCa-2 human pancreatic adenocarcinoma cell line. TF gene expression was characterized by Northern blot analysis, total cellular antigenic content by enzyme-linked immunosorbent assay and cell surface procoagulant activity by enzymatic assay. Invasion of tumour cells in vitro was determined by a standard Matrigel assay, and primary tumour growth was measured in immunodeficient mice.

RESULTS

Overexpression of the TF gene, confirmed by an increased signal on Northern blotting, was associated with increases in both total antigenic content for TF (P = 0.001) and cell surface procoagulant activity (P = 0.008) in sense cells compared with wild-type cells. Likewise, both in vitro tumour cell invasion (P = 0.001) and primary tumour growth (P = 0.007) were increased in sense transfectants.

CONCLUSION

Expression of TF enhances in vitro invasion and primary tumour growth of MIA PaCa-2 cells, suggesting that this procoagulant molecule might have a role in pancreatic tumour biology. Presented in part to the 83rd meeting of the Surgical Research Society, Oxford, UK, January 1996 and awarded the David Patey Prize, and in part to the 1997 Annual Meeting of the Association of Surgeons of Great Britain and Ireland, Bournemouth, UK, April 1997.

Prevention of venous thromboembolism in cancer patients

Thrombosis is a common complication in patients with malignancy and its occurrence is heightened by therapeutic interventions such as operations or the use of chemotherapy. The magnitude of the risk for venous thromboembolism (VTE) is well established for cancer surgery where rates twice that for abdominal surgery in noncancer subjects are described. The case for routine thromboprophylaxis in patients receiving chemotherapy is less clear, and prospective studies investigating rates of thrombosis by tumor type, stage of disease, and chemotherapeutic regimens are required. For thromboprophylaxis in the surgical patient either low-dose heparin or low-molecular-weight (LMW) heparin are effective and safe. For patients receiving chemotherapy in advanced breast cancer, low-dose warfarin is effective. Interestingly, heparin therapy may prolong survival in patients with malignant disease; the mechanism is unclear, and observations from retrospective analysis need to be confirmed in prospective studies.

The continuing challenge of exocrine pancreatic cancer

Carcinoma of the exocrine pancreas continues to have one of the poorest outlooks of any cancer. Although worthwhile gains in survival may be achieved by early diagnosis and referral to a specialist surgeon, further improvements are unlikely without reliable screening techniques and improved adjuvant therapy.

Duodenal leiomyosarcoma

Malignant stromal tumours of the duodenum are rare. The efficacy of surgical resection for duodenal leiomyosarcoma was assessed in 5 patients treated over an 11-year period, probably the largest series treated by a single surgeon. There were 3 women and 2 men with an age range of 27-52 years. Tumours were large (8.5-21 cm diameter) and partly cystic (4 cases). They arose from the second (2), third (2) and fourth parts of the duodenum. Resection was a major undertaking and comprised either partial duodenectomy (n = 4) or Whipple resection. Two patients required a right hemicolectomy in addition. Two patients with positive resection margins had adjuvant radiotherapy. Operative time ranged from 4.0 to 6.25 h and blood loss from 1.8 to 4.5 litres. Two patients developed complications: a transient low-output biliary fistula and an infected haematoma requiring percutaneous drainage. The 2 patients with incomplete resection died of recurrent disease at 3 and 15 months. The 3 survivors are free of disease at 24, 60 and 66 months. The results support a policy of aggressive resection despite the technical difficulties posed by these large and vascular tumours.

Experimental models of pancreatitis

Experimental animal models are helpful tools that have been employed to study pancreatitis for more than a century. Although not closely related to all aspects of the human disease, they have contributed greatly to our current understanding of the pathophysiology and cell biology of this disease. They have also become a standard means of testing innovative treatments against pancreatitis. This article reviews the experimental models of acute pancreatitis in common use, their severity, the criteria for the selection of an appropriate model, standards in monitoring and relevance to clinical disease. Despite their undoubted value in elucidating the mechanisms involved in the early cellular events and pathophysiology of acute pancreatitis, these models have not lent themselves to the development of effective new therapies. Models of chronic pancreatitis are also reviewed. The development of a reproducible model relevant to human chronic pancreatitis remains challenging. Experimental models of chronic pancreatitis have not yet added greatly to the understanding of the pathogenesis of this disease in man.

Increased nitric oxide activity in a rat model of acute pancreatitis

BACKGROUND

Overproduction of nitric oxide (NO) via induction of the inducible NO synthase (iNOS) is an important factor in the haemodynamic disturbances of several inflammatory states.

AIMS

To identify the role of NO in a caerulein induced model of acute pancreatitis in the rat.

METHODS

Arterial blood pressure and plasma NO metabolites were measured at zero and seven hours in adult male Wistar rats administered caerulein (n=10) or saline (n=10). Pancreatic activity of NOS (inducible and constitutive) was assayed biochemically. The pancreatic expression and cellular localisation of NOS and nitrotyrosine (a marker of peroxynitrite induced oxidative tissue damage) were characterised immunohistochemically.

RESULTS

Compared with controls at seven hours, the pancreatitis group displayed raised plasma NO metabolites (mean (SEM) 70.2 (5.9) versus 22.7 (2.2) micromol/l, p<0.0001) and reduced mean arterial blood pressure (88.7 (4.6) versus 112.8 (4.1) mm Hg, p=0.008). There was notable iNOS activity in the pancreatitis group (3.1 (0.34) versus 0.1 (0.01) pmol/mg protein/min, p<0.0001) with reduced constitutive NOS activity (0.62 (0.12) versus 0.96 (0.08) pmol/mg protein/min, p=0.031). The increased expression of iNOS was mainly localised within vascular smooth muscle cells (p=0.003 versus controls), with positive perivascular staining for nitrotyrosine (p=0.0012 versus controls).

CONCLUSIONS

In this experimental model of acute pancreatitis, iNOS induction and oxidative tissue damage in the pancreas is associated with raised systemic NO and arterial hypotension. Excess production of NO arising from the inducible NO synthase may be an important factor in the systemic and local haemodynamic disturbances associated with acute pancreatitis.

Enhanced expression of urokinase receptor induced through the tissue factor-factor VIIa pathway in human pancreatic cancer

Overexpression of tissue factor (TF) is characteristically observed in advanced pancreatic cancer and has been associated with invasion and metastasis. Functional responses of TF activation are here investigated using as a model system the human pancreatic cancer cell lines SW979 (which overexpresses TF) and MIAPaCa2 (which does not express detectable levels). After stimulation of these cell lines with factor VIIa (FVIIa), the only known TF ligand, expression of urokinase receptor (uPAR) gene was up-regulated in SW979 cells in a dose-dependent manner but not in MIAPaCa2 cells. Interestingly, urokinase (uPA) and its specific inhibitor PAI-1 were not up-regulated. Exposure to functionally inactivated FVIIa did not show any effect on uPAR expression on SW979 cells despite binding to TF with higher efficiency. The neutralizing anti-TF antibody 5G9 blocked the FVIIa-induced up-regulation of uPAR completely, whereas hirudin failed to block this up-regulation. Treatment of SW979 cells with Factor Xa did not up-regulate the expression of uPAR gene, whereas treatment with FVII induced the same level of enhanced uPAR gene expression as that with FVIIa. In the matrigel invasion assay, enhanced invasion of SW979 cell line induced by FVIIa was completely inhibited by anti-TF antibody and alpha2-antiplasmin. Moreover, the endogenous levels of uPAR gene expression were significantly correlated with the level of TF gene expression in 19 human cancer cell lines (P < 0.05). These data suggest that up-regulation of uPAR expression by tumor cells leading to tumor invasion is induced through the TF-FVIIa pathway rather than TF-initiated thrombin generation. This is the first report that TF may be one of the key receptors that can up-regulate expression of the plasminogen activator receptor in human cancer cells to enhance tumor invasion and metastasis.

Venous thromboembolism and cancer

The association of thrombosis with malignant disease has been recognized for well over 100 years. Evidence from experimental and clinical studies indicates that the haemostatic system is involved in the growth, invasion and metastasis of tumours. Laboratory parameters of haemostasis are frequently deranged in patients with cancer and overt thrombosis is common spontaneously where it may be the first sign of malignancy or secondary to therapy. The mechanisms by which coagulation activation facilitates the malignant process remain to be completely elucidated, but it is clear that cells and proteins of the coagulation and fibrinolytic systems are involved at many steps in the processes of tumour growth and dissemination. The low-molecular-weight heparins with their well-proven safety and efficacy profiles offer unique modalities for the prevention and treatment of cancer-associated thrombosis. They may also play a role in overall mortality reduction in patients with malignant disease.

Proliferation of parenchymal epithelial cells enhanced in chronic pancreatitis

This study was performed to determine whether pancreatic parenchymal epithelial cells in human chronic pancreatitis tissues retain a biologically significant capability to proliferate and, if so, within which epithelial compartment proliferation occurs. The techniques of immediate per-operative in vitro labelling with bromodeoxyuridine (BrdU) and conventional immunohistochemistry for Ki-67 antigen expression were used to identify proliferating cells. Concordance between the two techniques was confirmed in all tissues examined. In normal pancreas, proliferation was restricted to acinar epithelial cells, with no activity in the ductules. In chronic pancreatitis of both chronic obstructive and chronic calcifying types, the number of proliferating cells in the acini was significantly increased. A small population of proliferating cells was also apparent within ductules in chronic calcifying pancreatitis, but not in chronic obstructive pancreatitis. This investigation has shown that loss of parenchymal epithelium occurring in chronic pancreatitis is not caused by a primary failure of pancreatic 'stem-cell' proliferation, but is due to disproportionate attrition of differentiated parenchymal epithelial cells by a mechanism, possibly stromal in origin, which remains hitherto unidentified. The presence of proliferating ductular cells in chronic calcifying pancreatitis, but not chronic obstructive pancreatitis, suggests that distinct pathogenic processes may be operating in the former condition, which is classically regarded as secondary to ductal obstruction by stones, and in this single respect might be considered to be identical to chronic obstructive pancreatitis. Preservation of 'stem-cell' function supports the belief that regeneration of pancreatic parenchymal tissue could be a feasible proposition if biologically appropriate management strategies were developed to treat chronic calcifying pancreatitis.

Three-dimensional spiral CT angiography in pancreatic surgical planning using non-tailored protocols: comparison with conventional angiography

The aim of this study was to investigate three-dimensional spiral computed tomography (3DCT) as an adjunct to routine pancreatic CT scanning, with particular regard to the identification of surgically important hepatic arterial anomalies, correlated with conventional visceral angiography. 32 patients underwent spiral CT scans prior to pancreatic surgery using established protocols. Oral contrast medium was used throughout. 150 ml of intravenous contrast medium was given at 3 ml s-1 with a 24 s spiral CT sequence starting 35 s after the start of infusion. Two protocols were employed, both with a pitch of 1:3 mm table feed/collimation (n = 17) and 5 mm table feed/collimation (n = 15). Overlapping (1 mm minimum) axial reformats were reconstructed. 3DCT shaded-surface displays of the visceral arteries were assessed for visceral arterial anomalies. Visceral angiography (n = 23) was independently correlated. Satisfactory 3D angiograms were performed in all but one patient, in whom the coeliac axis was missed. (i) 3 mm protocol: 3DCT (n = 17) showed three anomalous right hepatic arteries (ARHA), one trifurcation anomaly and one splenic artery with an aortic origin. Angiography (n = 11) confirmed these findings, although one patient with an ARHA did not have angiography. A left gastric arterial supply to the left liver was not detected. (ii) 5 mm protocol: 3DCT (n = 15) showed two cases of ARHA. While confirming these findings, angiography (n = 12) showed a third case of ARHA, in which the coeliac and superior mesenteric artery had very close origins. A left gastric supply to the left liver was also missed. It is concluded that satisfactory 3DCT is possible without changing existing scanning protocols, although narrow sections are required for the confident assessment of right hepatic arterial anomalies, and any left hepatic supply via the left gastric artery was poorly assessed in this series.

Prevention of venous thromboembolism in cancer using low-molecular-weight heparins

Patients with cancer are at increased risk for venous and arterial thromboembolism and the principal interventions in such patients--surgical operation, chemotherapy or venous catheterization--heighten this risk. Thromboprophylaxis is indicated in cancer patients undergoing surgical operation and there is also evidence that thrombopropylaxis appears beneficial during chemotherapy, particularly for breast cancer, and possibly for ovarian and pancreatic carcinoma. Low-molecular-weight heparins (LMWHs) have shown promise as a thromboprophylactic agent in oncology patients, and offer significant benefits over standard heparin because of their improved safety profile and ease of use. There is emerging evidence that LMWHs may also favourably influence survival, possibly as a result of direct anti-tumour effects.

A characterization of the coagulant and fibrinolytic profile of human pancreatic carcinoma cells

The activation of coagulation and fibrinolytic pathways is well recognized in patients with malignant disease including those with carcinoma of the pancreas. The elaboration of activators and inhibitors of coagulation and of fibrinolysis has been assessed in 8 human pancreatic adenocarcinoma cell lines in vitro. Tissue factor (TF) was commonly synthesized with wide variations in the amount produced between cell lines, whereas its inhibitor (tissue factor pathway inhibitor, TFPI) showed lower but more consistent levels. Of the activators of fibrinolysis, urokinase was produced by all but one cell line, whereas tissue plasminogen activator expression was much less frequently seen. A correlation between low TF or high TFPI and cell doubling time was demonstrated. These data suggest a complex interaction of tumour-derived enzymes capable of interacting with most haemostatic mechanisms.

Effect of intraoperative nutritional solutions on perianastomotic colonic mucosa in experimental large bowel obstruction

We investigated the effect of intraoperative lavage with various solutions on the morphology of the mucosa adjacent to the anastomosis performed in left-sided colonic obstruction. After 24 hr of ligature obstruction to the pelvic colon, 108 male Wistar rats underwent colonic resection followed by primary anastomosis and were randomized for lavage with one of four different solutions: saline, povidone-iodine, 10% hypertonic glucose (HG), and short-chain fatty acids (SCFA). A control group had no lavage. The anastomotic region was studied both macroscopically and with light microscopy after three or six days. At day 3, lavaged animals, especially those with SCFA, had significantly smaller ulcers than controls, and at day 6 only rats lavaged with SCFA and HG were free of large ulcers. At day 3, median (interquartile range) crypt depth was higher in SCFA [360 (286-374) microm] and HG animals [306 (279-315) microm] when compared with controls [243 (225-252) microm; P < 0.05], and SCFA [67 (53-89)] rats showed more cells per crypt than controls [48 (39-52); P < 0.05]. No differences occurred on the sixth day. We conclude that intraoperative lavage with nutrient solutions, particularly with SCFA, has a trophic effect on the colonic mucosa. The suture line gap in the mucosa may be filled more quickly, thus contributing to improve the healing of a colonic anastomosis.

Spiral CT and the pre-operative assessment of pancreatic adenocarcinoma

AIM

To determine the value of spiral computed tomography (CT) in the pre-operative assessment of pancreatic carcinoma.

PATIENTS AND METHODS

Fifty patients with proven pancreatic carcinoma referred for pancreatoduodenectomy underwent pre-operative spiral CT using a dedicated pancreatic protocol to determine tumour resectability. Twenty-eight patients subsequently underwent surgical exploration.

RESULTS

Pre-operative imaging suggested that 15 tumours were resectable, and macroscopic clearance was complete in 13 giving a positive predictive value (PPV) of 87%. PPV of irresectability was 92%. CT underestimated locally advanced disease (n = 2), missed small hepatic metastases (n = 1), and lymphadenopathy (n = 1). CT overestimated SMV encasement in 1 case, otherwise prediction of vascular patency and compromise was correct. The conspicuity of small resectable carcinomas was improved by spiral scanning.

CONCLUSION

The optimised pancreatic parenchymal enhancement and vascular opacification achieved by spiral CT improves tumour detection of small carcinomas, allows accurate assessment of peripancreatic vessels, and reliably predicts both resectable and irresectable disease. CT remains inherently limited in the prediction of early extrapancreatic non-vascular spread and of lymphatic metastases.

Chronic pancreatitis and neoplasia: correlation or coincidence

Any link between pancreatic carcinoma and chronic pancreatitis could reflect the malignant potential of a chronic inflammatory process. Four patients with ductal adenocarcinomas had a long history of pancreatic pain (median duration 5 years) and showed clear-cut evidence of chronic pancreatitis "downstream" of the tumour. Four were alcoholics and two heavy smokers. These four cases arose within a surgical series of approximately 250 patients with chronic pancreatitis, giving an incidence of 1.6 per cent. The incidence and anatomical distribution of carcinoma and chronic pancreatitis could possibly be consistent with a casual relationship.