Effects of selected pharmaceutical products on phagocytic activity in Elliptio complanata mussels

Municipal wastewaters are recognized as a major source of pharmaceutical and personal care products to the aquatic environment, thereby exposing biota to unknown chronic effects. This study sought to examine the immunotoxic effects of pharmaceutical and urban waste products on the freshwater mussel Elliptio complanata. Hemolymph samples were collected and treated in vitro with increasing concentrations of various drugs (bezafibrate, carbamazepine, fluoxetine, gemfibrozil, morphine, naproxen, novobiocin, oxytetracycline, sulfamethazole, sulfapyridine and trimethoprim) and urban waste related chemicals (coprostanol, caffeine, cotinine) for 24 h at 15 degrees C. In a parallel experiment, mussels were caged and placed in two final aeration lagoons for the treatment of domestic wastewaters. At the end of the exposure period, hemolymphs were tested for phagocytic activity, intracellular esterase activity, cell adherence and lipid peroxidation (LPO). The products that most increased phagocytosis were bezafibrate, gemfibrozil and trimethoprim, while novobiocin and morphine reduced its activity. Intracellular esterase activity was reduced most strongly with sulfamethazole, novobiocin, gemfibrozil, bezafibrate and carbamazepine. Cell adherence was decreased by oxytetracycline, novobiocin and naproxen, and increased by gemfibrozil, bezafibrate and sulfapyridine. Exposure to these products also modulated LPO in hemocytes. Coprostanol and naproxen were more potent to reduce LPO while novobiocin and sulfapyridine were the most potent to induce LPO. The potential to induce LPO was positively correlated with the number of functional groups on the molecule (i.e., its nucleophilicity). Mussels exposed to domestic wastewater treatment plant aeration lagoons had decreased intracellular esterase and phagocytic activity as well, suggesting immunosuppression. PPCPs (pharmaceuticals and personal care products) that are recognized to disrupt cytokine signalling network by the nitric oxide pathway and cell permeability were generally the most potent ones. The data suggest that PPCPs have the potential to cause adverse effects on the immune system of bivalves.

Preliminary study of responses in mussel (Mytilus edilus) exposed to bisphenol A, diallyl phthalate and tetrabromodiphenyl ether

Environmental pollutants with hormonal activity including bisphenol, diallyl phtalate and tetrabromodiphenyl ether, have the potential to alter gonadal development and reproduction in aquatic wildlife. Little is known about the biological impact of environmentally relevant concentrations in mussels. To investigate some aspects of their potential estrogenic action, mussels were continuously exposed during 3 weeks. Gonadal development and vitellogenin like protein levels were examined. Bisphenol (50 microg/l) induced the expression of phospho-proteins in females and spawning in both sexes. Diallyl phthalate and tetrabromodiphenyl ether decreased phospho-protein levels in both sexes and induced spawning in males. Moreover, severe damaging effects on ovarian follicles and ovocytes were observed in both bisphenol A- and tetrabromodiphenyl ether-exposed female mussels.

Overview of key phytoplankton toxins and their recent occurrence in the North and Baltic Seas

The frequency and intensity of harmful algal blooms (HABs) appear to be on the rise globally. There is also evidence of the geographic spreading of toxic strains of these algae. Consequently, methods had to be established and new ones are still needed for the evaluation of possible hazards caused by increased algal toxin production in the marine food chain. Different clinical effects of algae-related poisoning have attracted scientific attention; paralytic shellfish poisoning, diarrhetic shellfish poisoning, and amnesic shellfish poisoning are among the most common. Additionally, cyanobacteria (blue-green algae) in brackish waters often produce neurotoxic and hepatotoxic substances. Bioassays with mice or rats are common methods to determine algal and cyanobacterial toxins. However, biological tests are not really satisfactory because of their low sensitivity. In addition, there is growing public opposition to animal testing. Therefore, there has been increasing effort to determine algal toxins by chemical methods. Plankton samples from different European marine and brackish waters were taken during research cruises and analyzed on board directly. The ship routes covered marine areas in the northwest Atlantic, Orkney Islands, east coast of Scotland, and the North and Baltic seas. The first results on the occurrence and frequency of harmful algal species were obtained in 1997 and 1998. During the 2000 cruise an HPLC/MS coupling was established on board, and algal toxins were measured directly after extraction of the plankton samples. In contrast to earlier cruises, the sampling areas were changed in 2000 to focusing on coastal zones. The occurrence of toxic algae in these areas was compared to toxin formation during HABs in the open sea. It was found that the toxicity of the algal blooms depended on the prevailing local conditions. This observation was also confirmed by monitoring cyanobacterial blooms in the Baltic Sea. Optimal weather conditions, for example, during the summers of 1997 and 2003, favored blooms of cyanobacteria in all regions of the Baltic. The dominant species regarding the HABs in the Baltic was Nodularia spumigena. However, in addition to high concentrations of Nodularia spumigena in coastal zones, other blue-green algae are involved in bloom formation, with changes in plankton communities influencing both toxin profiles and toxicity.

Transthoracic hepatic radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) is an alternative for the treatment of unresectable hepatic tumors. Tumors beneath the diaphragmatic dome may be difficult to access by laparoscopy. In these cases, a transthoracic transdiaphragmatic approach for delivering RFA can be used.

METHODS

Three patients with hepatic metastatic disease were treated using a transthoracic transdiaphragmatic approach to deliver RFA therapy for tumors in liver segments 7 and 8. The patients underwent thoracoscopy. The tumors were identified using transdiaphragmatic ultrasound, and transthoracic transdiaphragmatic RFA (TTRFA) was performed.

RESULTS

In three patients, TTRFA was successfully used to ablate five lesions. There were no perioperative complications, blood loss was minimal,and postoperative hospital stays ranged from 2 to 8 days. There were no recurrences during a follow-up period of 4 to 20 months.

CONCLUSIONS

TTRFA is a viable alternative for hepatic tumors located beneath the dome of the diaphragm that are difficult to access by laparoscopy.

Non-occlusive small bowel necrosis during enteral feeding after pancreaticoduodenectomy

BACKGROUND

Early enteral tube feeding is widely used after major surgery and trauma. This article is intended to alert surgeons to the possibility of small bowel necrosis following enteral refeeding and to discuss etiology and clinical features.

METHODS

A case series from a single surgeon's database at a Tertiary Care Center is reported. Cases were drawnfrom a consecutive series of patients undergoing pylorus-preserving pancreaticoduodenectomy and placement of a needle catheter jejunostomy between January 1998 and June 2004.

RESULTS

Two patients receiving early postoperative tube feeding developed sepsis with subsequent small bowel necrosis. Abdominal distension and signs of sepsis developed early postoperatively. Diagnosis was made based on characteristic computed tomography findings. Both patients underwent laparotomy with segmental bowel resection and survived.

CONCLUSION

Non-specific septic symptoms associated with recurrent abdominal distension are ominous signs in patients receiving early postoperative enteral tube feeding and should prompt discontinuation of enteral nutrition. Within this scenario, CT imaging represents a valuable adjunct in the early assessment of these patients.

Economic evaluation of laparoscopic and open inguinal herniorrhaphies: the effect of cost-containment measures and internal hospital policy decisions on costs and charges

BACKGROUND

Totally extraperitoneal (TEP) repairs of inguinal hernias, despite having a favorable clinical outcome are often criticized due to higher costs and charges associated with this approach. We, therefore, present a comparison of direct costs and charges between TEP and open tension-free (OPN) repairs, emphasizing the effect of cost-containment measures on the part of surgeons and the hospital's charging (rate-setting) policies on these measurements.

METHODS

Itemized direct costs, charges, and reimbursements were determined for 41 TEP and 44 OPN unilateral repairs done between January 1997 and December 1999. Multiple sensitivity analyses were done to evaluate the effect of cost-containment measures and the hospital's rate-setting policies on the differences in costs and charges between the two procedures. The hospital's profits were expressed as profit-cost ratios.

RESULTS

The mean direct cost for a TEP repair was $128.58 more than the OPN repair ($795.07[+/-65] vs 666.49 [+/-52]). However, mean charges and hospital reimbursement were $2,139.80 and $1,679.87, respectively, more for the TEP repairs. The profit-cost ratio was significantly higher in the TEP group (2.85:1 vs 1.07:1, P<.001). We found that 79.8% of the difference in direct costs vs 29% of the difference in charges between the two procedures was sensitive to cost-containment measures. Forty-five percent of the difference in charges was due to the hospital's nonuniform rate-setting policies. Long-term follow-up (38 months) showed no recurrence for either procedure.

CONCLUSIONS

The direct cost of TEP repairs with the minimal use of disposable instruments in a high-volume center is comparable to the OPN repair. However, due to differences in the hospital's charging policies, TEP repair would appear to be an expensive alternative from the payer's point of view.

A mathematical model for preoperative planning of radiofrequency ablation of hepatic tumors

BACKGROUND

Radiofrequency ablation (RFA) is rapidly evolving as an effective minimally invasive technique for the treatment of small and unresectable liver tumors. A potential cause of treatment failure is the inability to determine the optimum number of overlapping ablations needed to completely destroy tumors larger than the size of a single ablation. To clarify this relationship, we performed a mathematical evaluation that enables us to accurately estimate the number of ablations needed to completely ablate larger tumors.

METHODS

This estimation is based on the assumptions that complete ablation of the surface of a target tumor, including its blood supply, would completely destroy the tumor and that the tumor and ablations produced are perfectly spherical. The smallest possible number of partially overlapping ablations that would completely cover the surface of the target tumor is the same as the number of faces on a regular polyhedron that has a circumscribing diameter equal to or greater than the diameter of the target sphere.

RESULTS

This mathematical analysis shows that for a 5-cm ablation device, tumors with diameters ranging between 3.01 and 3.30 cm will require at least four ablations. Tumors between 3.31 and 4.12 cm require six overlapping ablations, and tumors between 4.13 and 6.23 cm require 12 overlapping ablations. The number of ablations needed for larger tumors and for 3-, 4-, 6-, and 7-cm ablation devices are also determined.

CONCLUSION

The smallest number of ablations required to completely ablate a spherical target tumor larger than the size of the ablation sphere increases dramatically as tumor size increases. Because this model is geometrically optimized, even a small change in the position of the ablation spheres with respect to the target sphere can leave potentially unablated tumor and thus result in treatment failure.

Laparoscopic radiofrequency ablation and hepatic artery infusion pump placement in the evolving treatment of colorectal hepatic metastases

BACKGROUND

Laparoscopic radiofrequency ablation (LRFA) and laparoscopic hepatic artery infusion pump (LHAIP) placement are new treatment options for patients with colorectal liver metastases. This study investigates the selection criteria, safety, efficacy, and preliminary outcomes of patients treated with LRFA and LHAIP placement.

METHODS

Fourty five patients with colorectal metastases confined to the liver, 37 of whom had failed systemic chemotherapy, were treated with LRFA and/or LHAIP between September 1996 and December 2001. Treatment selection was individualized, based on each patient's general health, liver function, and tumor size, number, location, and distribution.

RESULTS

Twenty patients (44%) had LRFA alone, 10 (22%) had LHAIP placement alone, and 15 (33%) patients had combined LRFA and LHAIP therapy. The LRFA group had a significantly shorter mean operative time and blood loss (p <0.05), but hospital stays were similar when compared to patients receiving LRFA + LHAIP or LHAIP alone. Tumor characteristics were worse in both LHAIP groups, with a higher incidence of tumors >or=4 cm, major vascular involvement, diffuse tumor pattern, bilobar distribution, and involvement of more than three segments. During a mean follow-up period of 11.5 +/- 7.8 months (range, 1-38), the actuarial survival was 70%, 67%, and 50% for LRFA, LRFA + LHAIP, and LHAIP, respectively. LHAIP only patients had the shortest estimated mean survival time of the three groups by Kaplan-Meier survival curves (p = 0.001).

CONCLUSION

LRFA and/or LHAIP placement are safe and feasible treatment options for the treatment of colorectal hepatic metastases. The choice of treatment for patients should be based primarily on tumor characteristics. Long-term studies, which will elucidate the role of these evolving treatments, are now under way.

The cytotoxic and genotoxic potential of surface water and wastewater effluents as determined by bioluminescence, umu-assays and selected biomarkers

Two bacterial tests employing Photobacterieum phosphoreum (Microtox bioluminescence test) and Salmonella typhimurium TA 1535 pSK1002 (umu-assay) were evaluated to estimate the cytotoxic and genotoxic potential of water samples from the selected rivers in Germany as well as the primary and secondary effluents of some sewage treatment plants. Rainbow trout (Onchorynchus mykiss) were exposed to different concentrations (20-40%) of secondary effluent in the model online aquatic monitoring plant WaBoLu-Aquatox. The toxic potential of water samples from the exposure tanks was determined in two prokaryotic test systems and the biomarkers acethylcholinesterase (AChE) activity in muscle tissue and DNA unwinding assay in liver tissue of fish. Samples from the tested rivers showed no inhibition of the bioluminescence of P. phosphoreum or growth of umu-bacteria. Only primary effluent samples from the treatment plants at the Saale River inhibited the light emission or the growth of test bacteria by more than 20%. The induction ratio of umu-bacteria was in most of the river samples less than the threshold for genotoxicity (IR < 1.5). Only some samples from the Saale River, especially at sites downstream of secondary effluents caused genotoxic responses in the umu-assay. Samples of primary effluents contained the greatest genotoxic potential up to GEUI = 6 which was not detectable in samples of secondary effluents. A concentration range 20-40% secondary effluent inhibited AChE activity in muscle tissue and significantly increased DNA fragmentation in liver tissue of rainbow trout. In contrast, no cytotoxic or genotoxic responses in the umu-assay were caused by water samples. Both bacterial methods can be successfully used to analyse the cytotoxic and genotoxic response of industrial and domestic wastewater and to estimate the effectiveness of sewage treatment units. However, because of their low sensitivity and high susceptibility, they are not reliable as a single test for the detection of cytotoxicity and genotoxicity in surface water. The application of prokaryotic tests systems with biomarkers such as AChE activity and DNA fragmentation in different tissues of test organisms seems to be a useful combination for the assessment of cytotoxic and genotoxic potential in surface water and secondary effluent.

Laparoscopic antireflux surgery in the elderly

BACKGROUND

Laparoscopic antireflux surgery is frequently denied to older patients with gastroesophageal reflux disease (GERD) because of a perceived higher operative complication rate, a decreased impact of the intervention on quality of life, and decreased cost effectiveness. This study compares disease severity, surgical outcomes, and impact on quality of life between elderly and young patients with GERD.

METHODS

Patients were selected from a prospectively maintained database of 1100 patients who underwent various laparoscopic esophageal procedures at our institution. Only patients having chronic intractable GERD and a minimum 6 months' follow-up were included in the study. Thirty elderly patients with a mean age of 71.2 years (SD +/- 5.6) were compared with a group of 30 younger patients (mean age, 43.9 +/- 12.8 years). Comparisons were made between subjective and objective outcomes, operative results, and health-related quality of life (HQRL) scores using SF-36 instruments.

RESULTS

The preoperative symptom assessment scores presenting frequency of symptoms on a 0-4 scale), and preoperative pH and manometry data were comparable in the two groups. Elderly patients had significantly higher ASA (American Society of Anesthesiologists) scores. Each group demonstrated a significant improvement in the postoperative symptom assessment scores and the esophageal functional studies (p<0.05). However, no significant differences were found in terms of postoperative complications, postoperative hospital stay, postoperative symptom scores, Demeester scores, or the HRQL data.

CONCLUSION

Laparoscopic antireflux surgery in elderly patients improves acid reflux and appears to be safe and effective as measured by postoperative testing in elderly and young patients.

Preoperative determinants of an esophageal lengthening procedure in laparoscopic antireflux surgery

BACKGROUND

In a minority of patients undergoing antireflux surgery, an esophageal lengthening procedure is required to reduce the gastroesophageal junction (GEJ) below the esophageal hiatus. We evaluated risk factors associated with an irreducible GEJ to identify clinical features that were predictive of the need for a Collis gastroplasty in patients undergoing laparoscopic antireflux surgery.

METHODS

Patients who required a Collis gastroplasty during a laparoscopic antireflux procedure (defined as the inability to reduce the GEJ > 2.5 cm below the esophageal hiatus despite extensive mobilization of the mediastinal esophagus) were compared to a random sample of patients who did not have a Collis gastroplasty. Predictors of the need for an esophageal lengthening procedure were identified using logistic regression modeling. Risks were expressed as odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Twenty patients who had a Collis gastroplasty were compared to 133 patients who had adequate esophageal length. The presence of a stricture (OR 3.0; 95% CI 1.0, 9.7), paraesophageal hernia (OR 3.5; 95% CI 1.3, 9.6), Barrett's esophagus (OR 3.7, 95% CI 1.3, 10.7), and re-do antireflux surgery (OR 6.4; 95% CI 2.0, 20.7) were associated with the need for gastroplasty. Patients with none of these factors were extremely unlikely to require a gastroplasty (OR 0.08; 95% CI 0.02, 0.34).

CONCLUSION

Patients undergoing laparoscopic antireflux surgery who are at high risk of needing an esophageal lengthening procedure can be easily identified preoperatively using simple clinical characteristics.

Toxicity of domoic acid in the marine mussel Mytilus edulis

The neurotoxic, immunotoxic and genotoxic effects of domoic acid (DA) on the blue mussel Mytilus edulis were investigated by biomarkers, acethylcholinesterase (ChE) activity in gills, DNA fragmentation in digestive glands, vitality and phagocytosis activity of haemocytes in haemolymph of mussels. After intra muscular injection of DA at the concentrations ranging from 1-500 ng/g body weight (bw), no neurotoxic effect was detected within incubation times of 48 h and 7 d. The vitality of haemocytes remained in all mussels at the level of control samples within 48 h, and increased significantly after 7 d (P<0.05). At DA concentrations ranging from 1 to 100 ng/g bw haemocytes suggested a great phagocytosis activity, but no alteration in their number by both incubation times. By increasing DA concentration of 500 ng/g bw, the number of haemocytes doubled in 48 h without any change in phagocytosis activity. Primary DNA lesions in digestive glands of all injected mussels were determined in acute phase of poisoning within 48 h, and rapidly repaired after 7 d of incubation.

Outcomes of laparoscopic herniorrhaphy without fixation of mesh to the abdominal wall

BACKGROUND

Recently there has been interest in performing laparoscopic herniorrhaphies without the use of staples or tacks to fix the mesh. Although mesh fixation has been linked to an increased incidence of nerve injury and involves increased operative costs, many surgeons feel that fixation is necessary to reduce the risk of hernia recurrence. This study evaluates the outcomes of laparoscopic herniorrhapies performed with and without mesh fixation at our institution.

METHODS

We retrospectively evaluated our last 172 laparoscopic herniorrhaphies, which span a period of conversion from staple fixation to nonfixation of total extraperitoneal herniorrhaphies using systematic chart review and follow-up self-administered questionnaires. The outcomes assessed were the incidences of postoperative neuralgia and hernia recurrence. Adjustment for important prognostic factors was achieved using Cox regression for estimating the risk of recurrence, and multiple logistic regression for estimating the risk of neuropathic complications.

RESULTS

Of 172 laparoscopic herniorrhaphies performed in 129 patients since July 1993, 105 were accomplished without mesh fixation, and 67 were performed with fixation of mesh to the abdominal wall. There were no significant differences in demographics between the two groups. A trend toward a higher incidence of neuropathic complications was observed in the mesh-fixation group (risk ratio [RR], 2.2; 95% CI, 0.5-10). A nonsignificant increased risk of hernia recurrence with fixation of mesh was observed (4.2 vs 1.6 per 100 hernia-years at risk; RR, 2.3; 95% CI, 0.4-13.10), but this finding may be associated with a selection bias with regard to giant hernia defects.

CONCLUSIONS

Our data suggest that mesh fixation to the abdominal wall may be avoided in total extraperitoneal repairs without increasing the risk of hernia recurrence and neuropathic complications. The increased risk of recurrence observed with mesh fixation possibly results from selection bias. Large randomized controlled studies are needed to determine whether mesh fixation is truly related to neuropathic complications and the incidence of recurrence.

Dedicated minimally invasive surgery suites increase operating room efficiency

BACKGROUND

The rapid adoption of laparoscopic surgery since the late 1980s added tremendous complexity into the operating room (OR) environment. For each case, a plethora of additional equipment-including monitors, video equipment, wiring, tubing, and cords-had to be set up, prolonging OR turnover time and decreasing OR efficiency. In 1993, the concept of designated minimally invasive surgery (MIS) suites was introduced. MIS suites integrated monitors and video equipment into the OR on ceiling-mounted columns and moved the controls to a centralized nursing station. The overall effect of this innovation on OR efficiency has not been measured.

METHODS

Five RNs with varying degrees of MIS experience were instructed on video setup and put-away criteria and then timed while performing a set of standardized tasks. Each set of tasks was performed twice using a standardized surgery model. Differences in setup and put-away times between MIS suites and standard ORs were tested using the t-test for paired comparisons.

RESULTS

The mean +/- standard deviation (SD) video setup times were 27.9 +/- 5.3 sec (MIS) and 254.3 +/- 54.0 sec (standard); the put-away times were 19.8 +/- 2.7 sec (MIS) and 222.3 +/- 26.0 sec (standard). The mean difference +/- standard error (SE) in both the setup (226.4 +/- 16.9 sec, p = 0.0001) and put-away times (202.5 +/- 8.6, p = 0.0001) were large and statistically significant.

CONCLUSION

Using a simulation model, we have demonstrated that the use of a MIS suite reduces video setup and put-away time significantly, with the potential for significant associated cost savings. This provides just one justification for the high cost of building such "ORs of the future."

A new monoclonal antibody against vitellogenin from rainbow trout (Oncorhynchus mykiss)

Monoclonal antibodies were developed against vitellogenin (vtg) of rainbow trout. This protein is used as a biochemical response to the exposure with estrogenic compounds. Several mice were immunized with purified vtg and the spleen cells of these mice were fused with myeloma cells. The resulting hybridoma cells were screened with an enzyme immunoassay for the production of specific anti-vtg antibodies. Twelve positive cell lines were detected. The hybridoma cell line B8D8 was adjusted to serum free medium; it produced monoclonal antibodies with a high selectivity and sensitivity. A detection limit of 5 microg/l vtg was achieved with a competitive enzyme immunoassay applying a preincubation step and a streptavidin-biotin amplification system (ABC system). Cross-reactivity with vtg of other species was detected with roach (Rutilus rutilus), flounder (Platichthys flesus) and dab (Limanda limanda). The assay was applied to rainbow trout (Oncorhynchus mykiss), which were exposed for six months to defined concentrations of effluents (10%, 20%, 30% and 40%) and surface water. Increased vtg levels in male fish are correlated with the increasing levels of effluent. The effluent levels in the exposure experiments are relevant for effluent loadings of the Berlin waterways during the seasons of the year.

The continuous monitoring of field water samples with a novel multi-channel two-stage mini-bioreactor system

Toxicity monitoring of field water samples was performed using a novel multi-channel two-stage mini-bioreactor system and genetically engineered bioluminescent bacteria for the continuous monitoring and classification of the toxicity present in the samples. The toxicity of various samples spiked with known endocrine disrupting chemicals and phenol was also investigated for system characterization. The field samples used in this study were obtained from two different sites on a monthly basis--from a drinking water treatment plant, referred to as site N, and from a stream near a dam which is currently being constructed, referred to as site T. These samples were either pumped or injected into the second mini-bioreactors to initiate the toxicity test. Most of the samples did not show any specific toxicity. However, one sample showed to have, based upon the detection results, and was deemed toxic. The samples spiked with phenol showed possible responses in the DPD2540 and TV1061 channels, indicating the occurrence of both membrane and protein damage due to phenol. In the tests using an endocrine disrupting chemical, bisphenol A, DNA damage was detected in the DPD2794 channel with a concentration of 2 ppm. Finally, a simple but novel early warning protocol that can be used in a drinking water reservoir and a suspected place where effluents of toxic materials enter the water sourse was suggested with a schematic diagram. In conclusion, this system showed good feasibility for use as a toxicity monitoring system in the field and as an early warning system, indicating if effluents are toxic.

Laparoscopic hepatic artery infusion pump placement

Patients with metastatic colorectal cancer limited to the liver are candidates for regional chemotherapy with implantable hepatic artery infusion (HAI) pumps. The poor prognosis of these patients, and the requirement of a laparotomy for placement, has deterred many oncologists from referral for HAI pump implantation. Minimally invasive surgical techniques are particularly well suited for the task of HAI pump placement in patients who may not tolerate the additional physiologic stress of a major surgical intervention. Advances in laparoscopic techniques allow pumps to be implanted safely and effectively, replicating the well-described tenets of open pump placement. The principal steps of the operation include a thorough laparoscopic evaluation to exclude extrahepatic disease, complete vascular isolation of the hepatic and gastroduodenal arteries, ligation of aberrant hepatic vessels, secure cannulation of the gastroduodenal artery, and confirmation of complete hepatic perfusion without extrahepatic perfusion. We describe the procedure and briefly review our clinical experience. We believe that the benefits typically derived from minimally invasive approaches (less pain, fewer perioperative complications, shorter hospitalization, faster recovery, and potentially less immune suppression) will be seen in these patients as well. If so, a completely laparoscopic approach to regional treatment of the liver may extend survival and improve the quality of life of patients whose prognosis is poor regardless of treatment. Controlled trials will be required to evaluate the added value of a laparoscopic approach to the placement of the hepatic artery pump.

Incidence of cancer of the pancreas, extrahepatic bile duct and ampulla of Vater in the United States, before and after the introduction of laparoscopic cholecystectomy

BACKGROUND

Some epidemiologic studies have identified cholecystectomy as a risk factor for pancreatic and biliary cancer.

METHODS

We compared the incidence of cancers of the pancreas, extrahepatic bile duct and ampulla of Vater before and after the widespread adoption of laparoscopic cholecystectomy in the United States in 1991, when the use of cholecystectomy increased dramatically.

RESULTS

Compared with 1980 to 1991, there was no increase in the incidence of cancer of the pancreas (adjusted incidence rate ratio [IRR] 0.97, 95% confidence interval [CI] 0.94 to 0.99) or extrahepatic bile duct (IRR 0.80, 95% CI 0.74 to 0.87) during 1992 to 1996. There was a small increase in the incidence of ampullary cancer (IRR 1.14, 95% CI 1.03 to 1.26).

CONCLUSIONS

We did not find clear evidence of a short-term increase in the incidence of cancers of the pancreas, bile duct, and ampulla of Vater, that was attributable to the increased use of cholecystectomy.

Quality of life before and after laparoscopic Heller myotomy for achalasia

BACKGROUND

Because the surgical treatment of achalasia is directed at the palliation of chronic symptoms, it is important to assess how surgery affects patients' health-related quality of life (HRQL).

METHODS

We evaluated upper gastrointestinal symptoms, satisfaction, and HRQL in 19 patients with achalasia before and after undergoing a laparoscopic Heller myotomy and partial fundoplication. HRQL was assessed using the Medical Outcomes Study 36-item short form health survey (SF-36).

RESULTS

The mean age of the patients was 40 years (range 16 to 74), and 58% were men. After a median follow-up of 21 months (range 2 to 35), 12 of 16 patients were satisfied with the results of their surgery. Liquid and solid dysphagia scores were improved after surgery, and the prevalence of heartburn symptoms did not change. Although all the health concepts measured by the SF-36 instrument showed some improvement, statistically significant increases (on a 0 to 100 scale) were detected in physical functioning (11.1, P = 0.02), role-physical (25.0, P = 0.05), bodily pain (12.2, P = 0.01), vitality (13.7, P = 0.02), and social functioning (18.4, P = 0.02).

CONCLUSIONS

Most aspects of HRQL improve after a laparoscopic Heller myotomy and partial fundoplication for achalasia.

A decision analysis of the optimal initial approach to achalasia: laparoscopic Heller myotomy with partial fundoplication, thoracoscopic Heller myotomy, pneumatic dilatation, or botulinum toxin injection

In the absence of randomized controlled trials that directly compare all of the modern methods of managing achalasia, decision analysis may help determine the optimal treatment strategy. Four strategies for the initial management of achalasia were compared using the following decision model: (1) laparoscopic Heller myotomy and partial fundoplication; (2) pneumatic dilatation; (3) botulinum toxin injection; and (4) thoracoscopic Heller myotomy. Probabilities of clinical events and utilities of health states were estimated using review of the medical literature and patient interviews. A recursive decision tree (Markov model) was used to simulate all the important outcomes of each initial treatment option, allowing for complications, relapses over time, and transitions between strategies when appropriate. After 10 years, laparoscopic Heller myotomy with partial fundoplication was associated with the longest quality-adjusted survival (quality-adjusted life years [QALY] = 7.41). The difference between this strategy and either pneumatic dilatation or botulinum toxin injection was small. Thoracoscopic Heller myotomy was associated with the poorest quality-adjusted survival (QALY = 7.15). Pneumatic dilatation was the favored strategy when the effectiveness of laparoscopic surgery at relieving dysphagia was less than 89.7%, the operative mortality risk was greater than 0.7%, or the probability of reflux after pneumatic dilatation was less than 19%. In a decision model, laparoscopic Heller myotomy with partial fundoplication is at least as effective as endoscopic approaches for managing achalasia symptoms. However, the differences are small enough that patient preferences and local expertise should be taken into consideration when tailoring a treatment plan for an individual patient.

Evaluation of estrogenic effects of municipal effluents to the freshwater mussel Elliptio complanata

Municipal effluents are an important source of estrogens to the aquatic environment. The purpose of this study was to examine the estrogenicity of municipal effluents to the indigenous freshwater mussel, Elliptio complanata. First, estradiol-binding sites in gonad homogenates were characterized to determine the binding affinity and specificity of estrogens. Mussels were exposed to increasing concentrations of a municipal effluent for 96 h at 15 degrees C. In another experiment, mussels were placed in cages and submerged for 62 days at 1.5 km upstream and 5 km downstream of a municipal effluent plume in the St. Lawrence River. Mussels were harvested for assessment of vitellogenin-like proteins in the hemolymph and determination of total lipid, carbohydrate and protein in the gonad. The presence of specific estrogen-binding sites was found in both male and female gonads. Binding of estradiol to cytosol proteins reached saturation, yielding a dissociation constant of 0.4 nM. Vitellogenin (Vg) levels increased significantly in both the hemolymph and the gonad after exposure to the effluent. Moreover, females appeared to be more sensitive than males to producing Vg. Mussels exposed in situ to contaminated surface waters had higher levels of Vg at the downstream site, again, females had higher levels of Vg than did males. On the other hand, lipid and sugar levels in male gonads were significantly increased at the downstream site. Moreover, mussels at the downstream site had decreased shell growth length and increased total and soft tissue weights. We conclude that municipal effluents contain bio-available xenoestrogens at levels sufficient to elicit effects in freshwater mussels.

Cost-effective management of common bile duct stones: a decision analysis of the use of endoscopic retrograde cholangiopancreatography (ERCP), intraoperative cholangiography, and laparoscopic bile duct exploration

BACKGROUND

There are a variety of approaches to the diagnosis and treatment of common bile duct (CBD) stones in patients undergoing laparoscopic cholecystectomy (LC).

METHODS

Decision modeling was used to evaluate the cost-effectiveness of four strategies for managing CBD stones around the time of LC: (a) routine preoperative endoscopic retrograde cholangiopancreatography (ERCP) (preoperative ERCP), (b) LC with intraoperative cholangiography (IOC), followed by laparoscopic common bile duct exploration (LCDE), (c) LC with IOC, followed by ERCP (postoperative ERCP), and (d) expectant management (LC without any tests for CBD stones). Local hospital data were used to estimate costs. Cost-effectiveness was expressed in terms of the cost per case of residual CBD stones prevented (in excess of the cost of LC alone). Diagnostic test characteristics, procedure success rates, and adverse event probabilities were derived from a systematic review of the literature. Sensitivity analysis was used to explore the effect of uncertainty on the results of the model.

RESULTS

LC alone was the least costly strategy, but it was also the least effective. Of the more aggressive strategies, LCDE and preoperative ERCP were associated with marginal costs of $5993.60 and $299,259.35, respectively, per case of residual CBD stones prevented. Postoperative ERCP was more costly and less effective than LCDE, but it had a lower cost-effectiveness ratio than preoperative ERCP when the prevalence of CBD stones was <80%.

CONCLUSIONS

Compared to other common approaches, laparoscopic CBD exploration is a cost-effective method of managing CBD stones in patients who undergo LC. If expertise in LCDE is unavailable, selective postoperative ERCP is preferred over routine preoperative ERCP, unless the probability of CBD stones is very high (>80%).

Effect of an esophageal bougie on the incidence of dysphagia following nissen fundoplication: a prospective, blinded, randomized clinical trial

HYPOTHESIS

Based on retrospective, uncontrolled studies, it has been claimed that Nissen fundoplication should be performed over an esophageal bougie to minimize postoperative dysphagia. We hypothesized that a surgeon experienced in laparoscopic fundoplication will have similar rates of postoperative dysphagia whether or not an esophageal bougie is used.

DESIGN

A patient and observer blinded, randomized, prospective clinical trial to assess the effect of intraoperative bougie use.

SETTING

A tertiary care teaching hospital that is a regional referral source for complex laparoscopic foregut surgical procedures.

PATIENTS

Three hundred thirty-six consecutive patients referred for laparoscopic fundoplication between March 1, 1996, and July 31, 1998, were evaluated for eligibility based on inclusion criteria and, if applicable, were offered randomization for fundoplication with or without a 56F bougie. One hundred seventy-one patients were enrolled in this study.

INTERVENTIONS

All patients underwent laparoscopic Nissen fundoplication, 81 with a bougie (hereafter referred to as the bougie group) and 90 without a bougie (hereafter referred to as the no bougie group).

MAIN OUTCOME MEASURES

Dysphagia severity and frequency were assessed by a blinded observer using a standardized scoring system. Incidence of complications related to the use or absence of a bougie, operative times, and postsurgical recovery was also assessed.

RESULTS

The mean operating time was 148 minutes (range, 65-295 minutes). The overall operative morbidity was 9% (7. 4% in the bougie group and 11% in the no bougie group, P=.41). One esophageal injury (1.2%) occurred in the bougie group. The 30-day mortality was 0. Long-term dysphagia assessment was completed in 90% of patients, with a mean follow-up of 11 months. Overall, long-term postoperative dysphagia was present in 13 patients (17%) in the bougie group and 24 patients(31%) in the no bougie group (P=.047). Severe dysphagia occurred in 5% of patients in the bougie group and 14% in the no bougie group.

CONCLUSION

This study confirms the dogma that use of a large-caliber stent during the creation of a fundoplication decreases the long-term incidence of dysphagia; albeit at the risk of injury from the introduction of a bougie.

Laparoscopic placement of a continuous hepatic artery infusion pump

Regional liver infusion chemotherapy has been used for several decades in the treatment of isolated hepatic metastases from colorectal cancer. Although implantation of infusion pumps has traditionally required a laparotomy, minimally invasive techniques have been used recently in an attempt to reduce the morbidity resulting from pump placement. This report describes a technique for laparoscopic pump placement and presents the investigators' results with this technique.

Factors predictive of dysphagia after laparoscopic Nissen fundoplication

BACKGROUND

Persistent postoperative dysphagia occurs in up to 24% of patients who undergo a laparoscopic Nissen fundoplication for reflux disease [7]. We hypothesized that patient history, pH testing, and esophageal manometry could be used to preoperatively identify patients at risk for this complication.

METHODS

Of 156 laparoscopic Nissen fundoplications performed over a 27-month period, we identified 19 patients (12%) who suffered from postoperative dysphagia longer than 3 months. The presenting complaint of preoperative swallowing difficulty was noted as was the presence of a known esophageal stricture. Preoperative pH testing and esophageal manometry were performed for all subjects. We compared the following parameters to an age and gender-matched control group: history of esophageal stricture, presence of preoperative dysphagia, DeMeester reflux score, upper esophageal sphincter pressure and relaxation, esophageal body motility, location of respiratory inversion point, and lower esophageal sphincter length, resting pressure, and relaxation. Data were compared via t-test and Fisher's exact test.

RESULTS

Patients who presented before surgery with complaints of difficulty swallowing were more likely to suffer from postoperative dysphagia (p = 0.029). Incidence of stricture, DeMeester score, and manometric measurements did not differ between the dysphagia and control groups (p > 0.05 for all parameters).

CONCLUSIONS

Although preoperative studies are not helpful in identifying patients at risk for persistent dysphagia after laparoscopic Nissen fundoplication, patients presenting with the preoperative complaint of difficulty swallowing are at increased risk for this complication.

Radiofrequency ablation lesions in a pig liver model

BACKGROUND

Radiofrequency (RF) ablation has been reported as a means of liver tumor destruction. This study evaluates the use of ultrasound monitoring of radiofrequency lesion creation and describes the morphology, histologic characteristics, and vascular effects of radiofrequency ablations in a pig liver model.

MATERIALS AND METHODS

Hemodynamic monitoring was established and laparotomies were performed in 50-kg pigs. Under ultrasound guidance, radiofrequency needle probes were placed in the liver at predetermined locations. Radiofrequency energy was applied over 15 min to generate lesions 3 cm in diameter. Eighty lesions were generated in 10 animals. At the completion of the experiment, the lesions were examined with ultrasound and then excised for CT, gross, and histologic examination.

RESULTS

There were no adverse systemic effects. Ultrasound imaging demonstrated the size, shape, and position of the lesions. Gross examination demonstrated a core of ablated tissue with a surrounding 1- to 2-mm hemorrhagic perimeter. Lesion volumes averaged 12.8 cc(3) (range 5-34 cc(3)). Final lesion shape and size were frequently altered by the cooling effect of local blood flow. Histologic stains demonstrated microvascular thrombosis and coagulative necrosis within the lesions. There appeared to be 100% cellular destruction within the lesion by cytochemical staining.

CONCLUSIONS

We demonstrated that RF ablation is capable of killing large volumes of normal liver tissue; however, local vasculature plays a significant a role in defining the ultimate size and shape of the lesion created. This may interfere with the utility of radiofrequency ablation as a modality for local tumor control.

Liver resection using total vascular exclusion, scalpel division of the parenchyma, and a simple compression technique for hemostasis and biliary control

Recent improvements in perioperative morbidity and long-term outcome following liver surgery have led surgeons to attempt larger and more technically challenging liver resections. Total vascular exclusion (TVE) of the liver during resection has been proposed as a technique that will facilitate these difficult resections while minimizing blood loss. Total vascular exclusion is performed by obtaining complete isolation of the vascular pedicle of the liver. Once the hepatic vein is clamped, rapid resections may be performed with a loss of only the blood volume contained within the liver itself. Safe performance of total vascular exclusion of the liver requires a thorough understanding of hepatic anatomy, patient selection criteria, and the physiologic changes incurred by hepatic exclusion and subsequent ischemia and reperfusion. The following report discusses these issues, gives a detailed description of the steps involved in obtaining safe total vascular exclusion, and presents a technique using rapid parenchymal excision with a scalpel and capsular compression to obtain hemostasis and prevent bile leaks. We briefly discuss our experience with 144 consecutive resections in which this technique was used.

Clinical short-term results of radiofrequency ablation in primary and secondary liver tumors

BACKGROUND

Radiofrequency ablation (RFA) is emerging as a new therapeutic method for management of solid tumors. We report here our experience in the use of this technique for management of primary and secondary unresectable liver cancers.

METHODS

Thirty-five patients with liver cancers were considered not suitable for curative resection at presentation: 8 with primary hepatocellular carcinoma ([HCC] 6 HCC and 2 fibrolamellar); 27 with metastatic liver cancer (17 colorectal carcinoma and 10 others). They were treated either with radiofrequency heat ablation (Radionics Europe N.V., Wettdren, Belgium) alone percutaneously and/or intraoperatively or in conjunction with surgical resections. The quality of RFA was based on the subjective feeling of whether the tumor was completely destroyed or not. The effectiveness of RFA was assessed according to clinical findings, radiographic images, and tumor markers at follow-up.

RESULTS

In 8 primary liver cases, 4 patients with a high level of alpha fetoprotein (AFP) benefited from the RFA with a 83.3% to 99.7% reduction of AFP. One with fibrolamellar hepatocellular carcinoma died 2 months after an incomplete percutaneous RFA from recurrence. The rest all had stable disease at the time of follow-up (mean 10.4 months). In patients with colorectal liver metastases, there were 4 deaths: 1 patient died postoperatively on the 30th day from a severe chest infection having shown a considerable reduction of carcinoembryonic antigen level (CEA, 8 versus 36 microg/L); 3 died from local and systemic disease, 1 at 12 months and 2 at 1 month, having had an incomplete RFA. The others had stable disease at follow-up (mean 7.6 months). Five patients underwent liver resections successfully with the application of RFA for residual lesions in the remaining contralateral lobe. In 10 patients with other liver tumors, 7 patients had stable disease at follow-up (mean 13.4 months); 1 patient had evidence of local and systemic recurrence 10 months after surgical resections with the intraoperative RFA and 2 patients died of systemic recurrence of disease 3 and 6 months after RFA alone. Two patients had liver resections in conjunction with the intraoperative RFA. The mean follow-up in our series was 8.5 months.

CONCLUSION

Radiofrequency heat ablation is useful as a primary treatment for unresectable liver cancers. The procedure can be used to treat the small residual tumor load in the contralateral lobe following liver resection in those considered unresectable at the first presentation. This new therapeutic strategy seems to increase surgical resectability in patients judged unresectable.

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.

Laparoscopic thermal ablation of hepatic neuroendocrine tumor metastases

BACKGROUND

Neuroendocrine tumor metastases to the liver are generally slow growing, but patients suffer from hormone hypersecretion despite aggressive multimodality therapy. A minimally invasive method of tumor ablation affords symptomatic improvement with minimal morbidity.

METHODS

Radiofrequency electrical energy is delivered to tissues via a 4-prong catheter resulting in tissue heating to 60 to 70 degrees C and cell death. Porcine studies were conducted to define appropriate parameters for energy delivery and then applied to patients using laparoscopic techniques.

RESULTS

In the porcine model 3.5 to 4 cm lesions were reproducibly created in 15 minutes using 30 to 50 W of power. The ablation process was monitored via temperature feedback from thermocouples in the catheter tips and by a hyperechoic blush noted on ultrasonography. Laparoscopic thermal ablation of 13 tumors in six patients with carcinoid (two patients), gastrinoma, insulinoma, nonsecreting islet cell cancer, or medullary thyroid cancer was performed. There were no intraoperative complications, and all patients were discharged the next day. Successful ablation was confirmed by spiral-computed tomography and by symptomatic improvement in patients with secreting tumors.

CONCLUSIONS

Laparoscopic thermal ablation of hepatic tumors is a novel, minimally invasive method of providing effective cytoreduction of neuroendocrine tumors metastatic to the liver.

Evaluation of laparoscopic Toupet fundoplication as a primary repair for all patients with medically resistant gastroesophageal reflux

BACKGROUND

This prospective study assesses the outcome results in 100 consecutive patients with gastroesophageal reflux disease (GERD) treated with a laparoscopic Toupet fundoplication.

METHODS

GERD was confirmed by 24-h pH study and/or esophagogastroduodenoscopy (EGD). Pre- and postoperative symptoms, operative times, and perioperative complications were recorded on standardized data forms. Early follow-up was at 3 months and late follow-up, including 24-h pH, manometry, and EGD was at 22 months.

RESULTS

Preoperative symptoms included heartburn (92%), regurgitation (58%), water brash (39%), and dysphagia (39%). Mean operative time was 3.2 hours. There were no conversions to celiotomy and there were no mortalities. The perioperative complication rate was 14%; 6% (5/83) of patients reported heartburn at 3 months and 20% (15/74) at 22 months. Early and late dysphagia was 20% (17/83) and 9% (7/74), respectively; 24-h pH testing was abnormal in 90% of symptomatic patients (9/10), 39% of asymptomatic patients (12/31), and 51% overall.

CONCLUSIONS

Despite early improvement in reflux symptoms following laparoscopic Toupet fundoplications, there is a high incidence of recurrent GERD. Symptomatic follow-up underestimates the true incidence of 24-h pH-documented reflux. Based on these results we cannot recommend the laparoscopic Toupet repair for GERD patients with normal esophageal motility.

New biosensors for environmental analysis

Environmental analysis requires fast and reliable measurement results. Biosensors, which facilitate integral monitoring as well as single substance analysis, achieve high sensitivities in a minimum of measuring time. Four new on-line biosensors, which cover a wide range of environmentally relevant substances, are introduced: A water-quality monitoring bacteria electrode, whose gradual development is described as an example, a heavy-metal screening urease inhibition sensor, a genotoxic potential as well as a immunotoxic potential indicating sensor. Future prospects are given.

Age-related differences in performance of stereotype arm movements: movement and posture interaction

Postural destabilizations in response to cyclic pull-and-push arm movements were compared in young and elderly subjects, with the goal of determining how age-related differences in postural stability influence strategies of cyclic arm movements made at different speeds, against different loads and while standing on support surfaces of different compliances. The results show that elderly subjects performed the experimental task more slowly with a lower mean movement frequency and a smaller amplitude. Despite of this fact, the elderly's upright posture was destabilized by this movement to a greater extent than in young subjects. The older adults exhibited lower damping of the disturbing torques produced by arm movements as evidenced by a higher amplitude of the center of foot pressure excursions. The results document close reciprocal motor and posture interaction and indicate that parameters of the voluntary movement task such as cyclic arm movements might be used as a sensitive measure of postural stability.

Effectiveness of water exercise on postural mobility in the well elderly: an experimental study on balance enhancement

BACKGROUND

The fear of falling may cause elderly people to limit their movement. As movement errors are known to facilitate the acquisition of motor skills, the elderly may inadvertently cause the loss of postural skills by constraining their movements, and hence avoid potential movement errors. It was hypothesized that by having elderly individuals exercise in a risk-free environment-water was utilized in this experiment-their postural capabilities would improve.

METHODS

Four groups of elderly subjects (80 +/- 5.8 years old) were placed into four groups: Water Exercisers; Land Exercisers; Water Sitters; and Land Sitters. Each group met twice per week for 45 minutes for 5 weeks of simple exercises or socializing in the designated medium. The distance each individual could reach (Functional Reach, FR) was measured at the end of each week.

RESULTS

Initially, each group was at risk (FR < 10 inches) for falling Statistical testing showed that the Water Exercisers (WE) increased their FR almost every week; the Land Exercisers (LE) increased only during the first week; and the Water Sitters (WS) and Land Sitters (LS) did not increase at all. The FRs after 5 weeks were 13.4 +/- 1.6 (WE), 11.3 +/- 1.5 (LE), 9.6 +/- 1.3 (WS), and 9.3 +/- 0.71 (LS) inches for each group, respectively.

CONCLUSIONS

The data showed that the postural capabilities in these elderly people, as measured by the FR, were enhanced by the production of movement errors that was facilitated in a water environment (in the case of the Water groups) or the initiation of a novel exercise program (Land Exercisers). Alternative explanations, and implication of these results, are discussed.

A miniaturized Ames mutagenicity assay employing bioluminescent strains of Salmonella typhimurium

Increased awareness of the role of environmental factors in carcinogenesis has led to an emphasis on preventing or minimizing exposure to genotoxicants. This is presently promoting the development of simple, rapid, cost-effective mutagenicity screening assays. We have developed a test system based on the well-known Salmonella mutagenicity assay. The lux genes, which permit cells to emit light through bioluminescence, were introduced into Salmonella typhimurium strain TA98. These bacteria were exposed for 48 h to chemicals or complex mixtures in 48-well microplates containing an appropriate liquid medium. Cells were subsequently centrifuged and resuspended in buffer. The final postexposure revertant biomass was then estimated using a microluminometer. Replication trials confirmed methodological reproducibility. Clear dose-response relationships were obtained with the direct frameshift mutagens 4NQO and 2NF. Mutagenicity threshold effect concentrations found for these compounds were comparable to those reported in the literature. Industrial effluents and environmental extracts (effluents, suspended solids) were also tested and results compared well with those of the SOS Chromotest. While further validation of this new adaptation of the Ames test will be required, it appears at this time that it could be well suited for routine screening of xenobiotics and environmental samples.

Decreased incidence of scoliosis in hearing-impaired children. Implications for a neurologic basis for idiopathic scoliosis

STUDY DESIGN

A retrospective survey of the incidence of positive scoliosis screenings in schools for the hearing impaired was performed.

OBJECTIVES

The incidence rate of scoliosis in a population with a high incidence of vestibular dysfunction was compared with the national normative incidence rate. The comparison was done to investigate the contribution of the vestibular system to scoliosis.

SUMMARY OF BACKGROUND DATA

Several reports have emphasized a possible neural etiology to idiopathic scoliosis. Based on the experimental hypothesis that an altered vestibular processing is critical for the production of scoliosis, 100 schools for the hearing impaired were surveyed to determine their incidence of positive screenings for scoliosis. Because it is known that hearing-impaired children have a high incidence of vestibular dysfunction, it was hypothesized that their screening incidence would change if the vestibular system contributed to idiopathic scoliosis.

METHODS

Surveys were sent to 100 schools for the hearing impaired asking for their most recent scoliosis screening data.

RESULTS

Of the 40 surveys returned, 28 schools for the hearing impaired conducted routine scoliosis screenings, of which 17 had demographics representative of the national norms. Of the 3127 students screened at these 17 schools, 1.2% of the students screened positive for scoliosis. This is significantly less than national incidence rate of 4%-10%.

CONCLUSION

The results suggested that hearing-impaired students may be a population that is protected from idiopathic scoliosis by a neural dysfunction. These data strongly suggest that idiopathic scoliosis has a neural etiology.

The effects of adrenergic agents on oxygen delivery and oxygen consumption in normal dogs

This study measured changes in whole body Do2 and Vo2 caused by the administration of exogenous adrenergic agents given at physiologically relevant doses. Using 25-kg nonseptic dogs, we calculated Do2 and directly measured Vo2 in six groups (saline control, colloid fluid challenge, dopamine, dobutamine, norepinephrine, and epinephrine). The dogs were anesthetized with isoflurane, paralyzed, and maintained at a minimum baseline temperature of 37 degrees C. Measurements were taken at six time points: baseline, after each of four successively larger doses of drug, and after a recovery period. Our results demonstrated no significant changes in Vo2 in either the saline control or colloid challenge groups over the 6-hour experiment despite marked increases in cardiac output and oxygen delivery during colloid challenge. At the maximum dose used, adrenergic agents increased Vo2 by the following: dopamine, 56%; dobutamine, 51%; norepinephrine, 43%; epinephrine, 61%. We conclude that adrenergic agents cause a significant increase in whole body Vo2 at moderate doses in normal dogs.

Changes in oxygen consumption relative to oxygen delivery in endotoxemic dogs given adrenergic agents

Adrenergic agents (AAs) have been used in critically ill patients to increase oxygen delivery (DO2). Associated parallel increases in oxygen consumption (VO2) have been noted and are thought to represent improved tissue oxygen utilization at supraphysiologic levels of DO2. We hypothesize that the increase in VO2 associated with the use of AAs in septic animals is secondary to direct, obligate, metabolic effects of the agents themselves. In this study, mongrel dogs were anesthetised, paralyzed, and had minimum temperature maintained on a warming blanket. Pulmonary and systemic hemodynamics were monitored. DO2 was calculated, while VO2 was measured directly with a metabolic cart. All dogs were given an Escherichia coli challenge and a colloid fluid resuscitation. Two hours after the onset of endotoxemia, baseline values were obtained, followed by four progressively larger doses of saline, dobutamine, or dopamine. At each dose there was a 40-min stabilization period and a 20-min measurement of hemodynamics and VO2. Data were analyzed using analysis of variance with a Scheffe's S test. P values of < 0.05 were considered significant. The control group slowly decreased VO2 during the 6-hr experiment to 73% of baseline. Dobutamine increased VO2 to 119% of baseline (31% above control) and dopamine to 111% of baseline (28% over control). We conclude that adrenergic agents cause a significant increase in whole body VO2 at moderate doses in septic dogs. It is likely, therefore, that the "pathologic" relationship between VO2 and DO2 described in critically ill patients is partially due to the direct metabolic effects of AAs.

Postural sway and perception of the upright stance stability borders

Decline in the perception of the borders of postural stability due to increase in sway was evaluated in young and elderly subjects. Ranges of lateral and anteroposterior postural sway were measured in eleven young and eleven elderly subjects during maximum voluntary excursions of center of gravity while leaning forward, backward, left, and right. In both age groups, displacement of the center of gravity out of the reference position resulted in increases in the range of sway in the plane corresponding to the direction of lean. Young subjects who further displaced their center of gravity within the base of support also exhibited significantly elevated anteroposterior sway range while leaning forward and backward, both in eyes-closed and in eyes-open experimental conditions. The elderly subjects, however, showed greater mediolateral oscillation of center of gravity while leaning forward with their eyes open. No significant intergroup differences in the anteroposterior sway range during leans in the mediolateral plane were found. However, a greater mediolateral component of sway range at lateral borders of stability was observed in the young adults. Analysis of signal-to-noise ratios indicated a greater decline in stability control in the elderly, due to impairment of perception of postural stability borders.

Investigations of phagocytosis concerning the immunological defence mechanism of Mytilus edulis using a sublethal luminescent bacterial assay (Photobacterium phosphoreum)

1. A simple method for the determination of phagocytosis activity using mussel hemocytes by measuring the bioluminescence is presented. 2. The immunological defence activity based on phagocytosis is measured and quantified by a luminescent bacterial assay with Photobacterium phosphoreum. 3. The measuring system allows us to establish the stress of the immunological defence mechanism of organisms exposed to chemicals and polluted rivers or sewage. Results with reference substances and the phagocytosis indices of exposed mussels from Norwegian aquaculture plants compared to those of mussels from the German Wadden Sea are given as examples.

Postural responses to changing task conditions

The experimental goal was to investigate discrepancies in the literature concerning postural adaptation and to determine if the prior presentation of horizontal perturbations affected the amplitude of responses to rotational perturbations. Surface EMG recordings from lower leg muscles (gastrocnemius (GAS) and tibialis anterior (TA)) were recorded in twelve subjects, and the amplitudes of the responses were statistically analyzed. We did not find differences between the responses to rotational perturbations which preceded or followed horizontal perturbations. This finding did not support the hypothesis that differences in the order of presentation of the different types of perturbations accounted for the discrepancies in the literature. Furthermore, our design did not show the progressive elimination of the GAS response within three to five sequential trials. Instead, we found a slow but significant response amplitude reduction over ten trials without yielding a permanent disappearance of the response. When analyzing the GAS responses to the rotational perturbations only, we found two components that contributed to the response reduction: 1) an initial reduction between trials one and subsequent trials, which could be due to habituation of a startle-like response; and 2) a second reduction which was more gradual. Our results also showed an immediate change in the response amplitude on the first trial, when the type of perturbation was changed. This is inconsistent with the view that ankle musculature stretch and joint movement are the primary inputs driving the postural responses. Since small ankle dorsiflexing rotations produced by the platform translations caused large GAS responses while large ankle dorsiflexing rotations produced by direct platform rotations caused small GAS responses, this suggests that multiple sensory inputs contribute to the responses. We propose that an initial compensation to a new perturbation type occurs within the first trial by the integration of these divergent sensory inputs.

[Microbiological studies of PVC packing sheets and sediments from a wet cooling tower]

On surface of PVC packing sheets in wet cooling towers thick sediment layers can often be observed (Fig. 1) which usually cause several technological troubles. Microbiological investigations were made in order to estimate whether some hygienic risk possibly based on the proliferation of hygienic relevant microorganisms in the sediment have to be considered. An abundance of bacteria actinomycetes and fungi was found in the sediments from PVC packing sheets which were exposed for 6 or 20 weeks in a wet cooling tower (Table 2). However, the microbial (colony) counts usually decreased when the exposition time increased. Pseudomonas aeruginosa was not detected at all. Coliform bacteria and Escherichia coli showed a declining development both in the sediment and in the cooling water unter test (Table 3). Total volume of plankton also decreased in cooling water incubated with small pieces of PVC packing sheets. The results indicate the sediment formation on PVC packing sheets in wet cooling towers probably not to be problem of environmental hygiene but technology. The sediment formation seems to depend mainly of the quality (i.e. pollution degree) of cooling water and also of surface properties of the packing sheets.

Hepatic microsomal O-de-ethylases in cod (Gadus morhua): their induction by Aroclor 1254 but not by Aroclor 1016

1. The characteristics of hepatic ethoxycoumarin and ethoxyresorufin O-de-ethylases in juvenile cod (Gadus morhua) from the North Sea are described. 2. Feeding Aroclor 1254 to juvenile cod to produce liver concentrations of approx 900 microgram X g-1 (wet wt) induced ethoxycoumarin O-de-ethylase approx 30-fold, but had no effect on ethoxyresorufin O-deethylase activity. 3. Feeding Aroclor 1016 to juvenile cod to produce liver concentrations of approx 300 micrograms X g-1 (wet wt.) did not induce ethoxycoumarin O-de-ethylase activity.