bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of the Economics of Biological Natural Resources
Authors: White Ben
Published: September 2010

The economics of renewable biological resources originated in the 1950s in fishery economics. The original models were static and linked simple population growth models to harvesting. In the 1970s the subject became more concerned with dynamic models and the stability of resource systems and this development continued in the 1980s. Now renewable resource economics is seen as a branch of capital theory which is distinct from mainstream capital theory because it must simultaneously represent the productivity of an ecosystem as well as the production functions of the firms which exploit it. Adding to this complex patterns of ownership over the resource itself and the dependence of production on the state of the ecosystem makes for a set of problems which economists have only started to address. Progress in renewable resource economics will come through closer collaboration with ecologists to give more realistic population models; the development of approaches for multi‐species ecosystems; and the use of modelling techniques and policies which can adapt as more information becomes available on the status of a resource. In the future renewable resource economics will continue to contribute to the sustainability debate by providing a clearer analysis of the trade‐off between ecosystem stability and the level of economic exploitation.
Modelling Farmer Entry into the Environmentally Sensitive Area Schemes in Scotland
Authors: Wynn Gerard , Crabtree Bob , Potts Jacqueline
Published: September 2010

The probability and rate of farmer entry into the Environmentally Sensitive Area (ESA) scheme were investigated by multinomial logit and duration analysis respectively. Models were based on a survey of 490 farmers sampled from across all ten ESAs in Scotland. The results indicated a number of generic factors as important in explaining the entry decision. Non‐entrants were less aware of and less informed about the scheme than entrants. The probability of entry was increased where the scheme prescription fitted the farm situation and the costs of compliance were low. The duration analysis suggested several factors accelerating scheme entry: an interest in conservation, more adequate information and more extensive systems.
Parametric and Non‐Parametric Estimates of Willingness to Pay for Forest Recreation in Northern Ireland: A Discrete Choice Contingent Valuation Study with Follow‐Ups
Authors: Hutchinson W. George , Scarpa Riccardo , Chilton Susan M. , McCallion T.
Published: September 2010

In this study we show that forest areas contribute significantly to the estimated benefits from outdoor recreation in Northern Ireland. Secondly we provide empirical evidence of the gains in the statistical efficiency of both benefit and parameter estimates obtained by analysing follow‐up responses with Double Bounded interval data analysis. As these gains are considerable, it is clearly worth considering this method in CVM survey design even when moderately large sample sizes are used. Finally we demonstrate that estimates of means and medians of WTP distributions for access to forest recreation show plausible magnitude, are consistent with previous UK studies, and converge across parametric and non‐parametric methods of estimation.
Economics of Soil Conservation: The Upper Mahaweli Watershed of Sir Lanka
Authors: Vieth Gary R. , Gunatilake Herath , Cox Linda J.
Published: September 2010

This paper estimates the benefits and costs of soil conservation in the Upper Mahaweli Watershed of Sir Lanka. The costs of soil erosion control include the implementation costs of control measures, while the benefits are reductions in the costs of soil erosion. In contrast to many studies in developed countries, the on‐site benefit of soil erosion control in Sri Lanka is estimated to be greater than the off‐site benefit While a social benefit‐cost analysis demonstrates that it is socially desirable to implement conservation measures, the private financial analyses indicate that it is feasible for individual farmers to adopt the conservation measures. Despite private economic feasibility, programs addressing farmers' reluctance to adopt soil conservation measures may be preferable to public intervention in soil conservation activities when the on‐site benefits are greater than the off‐site benefits.
Decomposing Preference Shifts for Meat and Fish in the Netherlands
Authors: Mangen M.‐J.J. , Burrell A.M.
Published: September 2010

The changing preferences of Dutch consumers for meat and fish are investigated using a switching almost ideal demand system. Structural change in demand between January 1994 and May 1998 is decomposed into underlying trends, temporarily irreversible preference shifts triggered by the BSE crisis of March 1996, and a “panic” reaction against beef in the month of the crisis itself. Preference shifts due to the BSE scare reduced expenditure shares for beef, minced meat and meat products by 2.5, 3.3 and 7.9 percentage points respectively. There were offsetting gains in the shares of pork, prepared meat and fish. Taking underlying trends also into account, changing preferences over the whole period reduced beefs share by 4.9 percentage points and increased those of poultry, prepared meat and fish by 4.1, 4.9 and 5.2 percentage points respectively.
The Effects of Transaction Costs, Power and Risk on Contractual Arrangements: A Conceptual Framework for Quantitative Analysis
Authors: Dorward Andrew
Published: September 2010

Increased reliance on commercial traders in liberalised agricultural markets poses questions about the nature of contractual relations between traders and farmers; about welfare, efficiency and equity characteristics of these relations; and about conditions necessary for traders to engage in these markets. A new institutional economics analysis seeks to understand the institutions that affect transaction costs and risks for each party, and power relations between them. Transaction cost analysis has not, however, developed a unifying conceptual or quantitative framework to integrate these issues. This paper develops a methodology for modelling negotiated choice of contractual arrangements in buyer/seller relationships, taking account of the socioeconomic characteristics of each party, economic and technical characteristics of the commodity, and the institutional environment. The model is setup as a non‐linear programming problem. The approach provides a framework for the application of transaction cost economics to quantitative empirical study of markets, to individual firms' supply chain decisions, and to the analysis of policy interventions in markets.
Determinants of Agricultural Protection: The Role of Democracy and Institutional Setting Alessandro Olper
Authors: Olper Alessandro
Published: September 2010

This paper deals with the effects of democracy and institutional setting on agricultural protection in 35 developed and developing countries during 1982–1992. Regression analysis is conducted to test the effects of three alternative measures of democracy and two composite indices of the quality of institutions that protect and enforce property rights. After controlling for many other political and economic determinants of agricultural protection, the paper shows that democracy affects protection positively, but it is not the level of democracy per se that seems to matter. On the contrary there is strong evidence that the quality of institutions that protect and enforce property rights is a key determinant of agricultural protection. This empirical result is robust to changes in institutional proxy, country sample and statistical problems.
A Note on Distributive Equity and Social Efficiency
Authors: Romero Carlos
Published: September 2010

This note proposes a social welfare function (SWF) where most functions, such as the Benthamite or the Rawlsian functions, found in the literature can be considered particular cases. Moreover, the SWF propounded let us obtain compromises or balances between the welfare criteria of social efficiency and distributive equity. The level of compromise or balance is established with the help of a simple and operational parameter.
Agricultural Economics and Rural Development: Marriage or Divorce? Presidential Address
Authors: Thomson Kenneth J.
Published: September 2010

Rural development is a growing field of interest, both in policy and conceptual terms. However, it is sometimes loosely defined, and statistical information is therefore often confusing. This paper attempts to clarify some of the concepts involved, and then to explore the relationship between the study of rural development and that of agricultural economics. It is argued that much would be gained by a clearer separation between the economics of land, covering its environmental aspects as well as food production, and that of the rural population and economy. Links between the two certainly exist, but are better recognised individually, by analysts and policymakers alike.
Damage Control Productivity: An Input Damage Abatement Approach
Authors: Lansink Alfons Oude , Carpentier Alain
Published: September 2010

This paper compares the value of the marginal product of three different pesticides from different specifications of the production function. The specifications are the output damage abatement specification proposed by Lichtenberg and Zilberman, a general input damage abatement specification and a traditional production function. These specifications are estimated on panel data of specialised Dutch arable farms over the period 1989–1992, using Generalised Maximum Entropy estimation. Results of the input damage abatement specification show that pesticides have different impacts on individual productive inputs, although statistical evidence is weak. The output damage abatement specification produces statistically more significant relations, but imposes restrictions that are only partly supported by the data. It is also found that estimation of a quadratic traditional production function, that treats damage abatement inputs in the same way as productive inputs, does not lead to over estimation of the value of the marginal product as previous authors have hypothesised.
Optimisation of a Large, Constrained Simulation Model using Compressed Annealing
Authors: Doole Graeme J. , Pannell David J.
Published: September 2010

Simulation models are valuable tools in the analysis of complex, highly constrained economic systems unsuitable for solution by mathematical programming. However, model size may hamper the efforts of practitioners to identify efficiently the most valuable management strategy. This paper investigates the efficacy of a new stochastic search procedure, compressed annealing, for the identification of profitable solutions in large, constrained systems. The algorithm is used to examine the value of incorporating a sown annual pasture, French serradella (Ornithopus sativusBrot. cv.Cadiz), between extended cropping sequences in the central wheatbelt of Western Australia. Compressed annealing is shown to be a reliable means of considering constraints in complex optimisation problems relative to the incorporation of fixed penalty factors in standard simulated annealing and genetic algorithms. French serradella is found to be an economic break pasture in the study region when weed populations are high or sheep production is lucrative.
An Experimental Study on Particular Physical Properties of Several Interocclusal Recording Media. Part III: Resistance to Compression After Setting
Authors: Michalakis Konstantinos X. , Pissiotis Argiris , Anastasiadou Vassiliki , Kapari Danai
Published: September 2010

Purpose:
The purpose of this study was to evaluate the resistance to compression after setting of several elastomeric interocclusal recording materials.

Materials and Methods:
Testing of the resistance to compression after setting was performed following a modification of the method described in specification No. 19 (4.3.6) of the A.D.A., for the elastomeric impression materials—1 cylindrical stainless steel mold with an internal diameter of 20 mm and a height of 20 mm was constructed. Mixing of the interocclusal registration media was conducted according to manufacturers' instructions, and the materials were injected into the mold. Two subsequent loads, one of 100 g/cm2 and a second of 1000 g/cm2 were exerted on each sample. The deformation of each was calculated using a vertical traveling micrometer microscope with an accuracy of ± 0.001 mm.

Results:
One‐way ANOVA revealed significant differences among the materials (F= 331.58, p < 0.0005). Tukey's HSD (p < 0.05) test was used to determine the significant differences between the materials.

Conclusions:
Polyvinylsiloxane Blu Mousse displayed the greatest resistance to compression, as compared to other elastomeric interocclusal recording materials tested.
In Practice Evaluation of a Denture Adhesive Using a Gnathometer
Authors: Psillakis Jason J. , Wright Robert F. , Grbic John T. , Lamster Ira B.
Published: September 2010

Purpose:
This study measured the extent to which the performance of a maxillary complete denture can be improved with the use of a denture adhesive. This in‐practice evaluation assessed both a quantitative measure (force until dislodgement), without and with the adhesive, and patients' perception regarding the use of adhesive.

Materials and Methods:
A total of 194 patients (77 men, 117 women) who wore maxillary complete dentures were tested for denture performance both without and with denture adhesive. A simple gnathometer was used. Patient perceptions were also assessed by a questionnaire and analyzed for denture performance as well as the effects on speaking and chewing, fit and comfort, and perceived confidence.

Results:
There was a 63.4% improvement in bite force dislodgement with the use of a denture adhesive. A total of 79.2% of the patients perceived better denture performance (bite force dislodgement) with adhesive use. A total of 55.7% perceived an improvement in speaking and chewing. A total of 56.2% noticed the fit and comfort were better. A total of 63.9% responded that they had improved confidence.

Conclusions:
Use of a denture adhesive can improve the incisal (or protrusive) biting force for patients who wear a maxillary complete denture. Subjectively, the patients reported an improved perception of denture performance and that the use of adhesive provided greater confidence when using the prosthesis.
Cancer Pain: Progress Since the WHO Guidelines
Authors: Burton Allen W. , Cleeland Charles S.
Published: September 2010

Abstract: In has been 15 years since the WHO Guidelines for the management of cancer pain were developed. This article reviews the guideline development and its effectiveness. Current trends in cancer care utilizing aggressive chemotherapeutic and surgical protocols lead to many patients living longer with advanced cancer and an attendant increase in pain. Future trends in cancer pain care are outlined.
Pain Generators of the Lumbar Spine
Authors: Sizer Phillip S. , Phelps Valerie , Matthijs Omer
Published: September 2010

Abstract Different anatomical structures and pathophysiological functions can be responsible for lumbar pain, each producing a distinctive clinical profile. Pain can arise from the intervertebral disc, either acutely as a primary disc related disorder, or as result of the degradation associated with chronic internal disc disruption. In either case, greatest pain provocation will be associated with movements and functions in the sagittal plane. Lumbar pain can also arise from afflictions within the zygapophyseal joint mechanism, as result of synovitis or chondropathy. Either of these conditions will produce the greatest pain provocation during three‐dimensional movements, due to maximal stress to either the synovium or joint cartilage. Finally, patients can experience different symptoms associated with irritation to the dural sleeve, dorsal root ganglion, or chemically irritated lumbar nerve root. Differential diagnosis of these conditions requires a thorough examination and provides information that can assist the clinician in selecting appropriate management strategies.
Anesthesia (17)
Authors: Goldstein Andrei , Grimault Patrick , Henique Aude , Keller Michele , Fortin Anne , Darai Emile
Published: September 2010

Preventing postoperative pain by local anesthetic instillation after laparoscopic gynecologic surgery: a placebo‐controlled comparison of bupivacaine and ropivacaine. (Hotel‐Dieu Hospital, Paris, France) Anesth Analg 2000;91:403–407.

This study tested the hypothesis that local anesthetics instilled at the end of laparoscopic gynecologic procedures are able to prevent postoperative pain at wake‐up and during the first 24 h. A total of 180 patients were randomly assigned into three groups to receive an intraperitoneal instillation of 20 mL of either bupivacaine 0.5% (Group B), ropivacaine 0.75% (Group R) or saline (Group S) at the end of surgery. All patients received analgesia with acetaminophen and ketoprofen IV infusions. Pain was assessed by using a 0‐10 graded numerical scale (NS) every 5 min in the postanesthesia care unit and IV morphine was administered if NS was> 4. Assessment of pain continued every 4 h on the ward, and subcutaneous morphine was injected if needed to keep the NS score <4. Postoperative nausea and vomiting (PONV) was rated on a 4‐point scale. The morphine consumption at wake‐up and over the first 24 h was significantly lower (P<0.05) in Group B (mean, 0.92 mg at wake‐up; 3.08 mg over 24 h) and in Group R (mean, 0.25 mg at wake‐up; 0.69 mg over 24 h), than in Group S (mean, 4.18 mg at wake up; 12.93 mg over 24 h). The morphine‐sparing effect of ropivacaine was significantly greater than that of bupivacaine. Both local anesthetics were effective in the prevention of PONV. Conclude that local anesthetics should be instilled in all gynecologic patients at the end of all laparoscopic procedures.
Basic Science (21)
Authors: Takenami Tamie , Yagishita Saburo , Asato Fumio , Hoka Sumio
Published: September 2010

Neurotoxicity of intrathecally administered tetracaine commences at posterior roots near entry into the spinal cord. (Kitasato University, Kanagawa, Japan) Reg Anesth Pain Med 2000;25:372–379.

This study examined the histopathologic effects of intrathecally administered tetracaine. Sixty Wistar rats randomly received either 20%, 10%, 5%, 3%, 1%, 0.5%, or 0% tetracaine dissolved in 10% glucose solution or no solution via a chronically implanted intrathecal catheter. The spinal cord at L1, posterior and anterior roots and cauda equina were excised 5 days later, sectioned, processed, and prepared for light and electron microscopic examinations. Rats treated with tetracaine at 10% or 20% developed lesions in the posterior white matter and posterior roots. Rats injected with 3% or 5% tetracaine developed lesions, which began in the posterior roots close to the spinal cord and extended to the posterior white matter. The lesions were characterized by axonal degeneration. Injections of 1% of tetracaine did not cause any pathological changes. The results suggest that the initial target of intrathecal tetracaine neurotoxicity may be the posterior roots at their entry into the spinal cord, where the axons are devoid of myelin sheath and thus represent a sensitive area for neurotoxic change.

Comment by James E. Heavner, DVM, PhD.

The reassuring aspect of this study is that no significant lesions were found when rats were given clinically used concentrations of tetracaine. The investigators do make a case that clinically used concentrations of tetracaine might be neurotoxic in humans based on the observation that the duration of action of tetracaine is shorter in rats than in humans. The distribution of the lesions is curious in that 10% tetracaine produced lesions in the posterior rootlets and in the posterior rootlet entry zone, but did not produce lesions in the fasciculus gracilis. The implication is that rootlets posterior to lamina L1 (the L1 segment that was examined) that were destroyed do not project into the fasciculus gracilis. One would expect that destruction of lamina L2 posterior rootlets that projected into the fasciculus gracilis would produce lesions visible at the EM level at L1 5 days after damage. The absence of lesions in the L1 fasciculus gracilis puzzles me. I am also puzzled by the suggestion that all posterior rootlets loose their myelin sheath just before entry into the posterior white matter of the spinal cord (Obersteiner‐Redlich zone). To my knowledge, most posterior rootlets do not have this nonmyelinated zone and; therefore, the absence of the myelin would make only a portion of the posterior rootlets vulnerable to tetracaine neurotoxicity as suggested by the authors. In short, there are some anatomical relationships that do not fit with the distribution of lesions described by the investigators.
Basic Science (22)
Authors: Nishiyama Tomoki , Ho Rodney J.Y. , Shen Danny D. , Yaksh Tony L.
Published: September 2010

The effects of intrathecal morphine encapsulated in l‐ and d‐dipalmitoylphosphatidyl choline liposomes on acute nociception in rats. (University of California, San Diego, CA) Anesth Analg 2000;91:423–428.

This study evaluated the antinociceptive effects of morphine encapsulated in liposomes of two isomeric phospholipids, l‐dipalmitoylphosphatidyl choline (l‐DPPC) and d‐dipalmitoylphosphatidyl choline (d‐DPPC), in comparison with morphine in saline. Sprague‐Dawley rats with chronic lumbar intrathecal catheters were tested for their acute nociceptive response using a hindpaw thermal escape test. Their general behavior, motor function, pinna reflex, and corneal reflex were also examined. The duration of antinociception was longer in both liposomal morphine groups than in the free morphine group. The peak antinociceptive effects were observed within 30 min after intrathecal morphine, l‐DPPC or d‐DPPC morphine injection. The rank order of the area under the effect‐time curve for antinociception was l‐DPPC morphine> d‐DPPC morphine> morphine. The 50% effective dose was: 2.7 μg (morphine), 4.6 μg (l‐DPPC morphine), and 6.4 μg (d‐DPPC morphine). d‐DPPC morphine had fewer side effects for a given antinociceptive AUC than morphine. Conclude that l‐DPPC and d‐DPPC liposome encapsulation of morphine prolonged the antinociceptive effect on acute thermal stimulation and could decrease side effects compared with morphine alone.

Comments by James E. Heavner, DVM, PhD.

One would intuitively expect that encapsulation of a drug would prolong its duration of action and reduce systemic side effects. However, the results of this study taken in the context of studies with the encapsulation of other opioids indicate that the physical/chemical properties of the opioid can have an important influence on the results of encapsulation. For example, the investigators have demonstrated that encapsulation of alfentanyl had only a modest effect on its duration of action, presumably because of the ability of the lipophilic alfentanyl to rapidly defuse through the membranes of the liposomes. One question the study leaves open is whether or not the material used for encapsulation has consistent effects on its own. The investigators previously found that intrathecal delivery of l‐dipalmitoylphosphatidyl choline resulted in a steroid‐sensitive allodynia. However, in the present study the investigators did not observe this. Thus, there is much to be learned about the science and art of drug encapsulation for therapeutic purposes in humans.
Basic Science (27)
Authors: Xu Mei , Kontinen Vesa K. , Kalso Eija
Published: September 2010

Effects of radolmidine, a novel α2‐adrenergicagonist compared with dexmedetomidine in different pain models in the rat. (University of Helsinki, Helsinki, Finland) Anesthesiology 2000;93:473–481.

This study determined the antinociceptive and sedative effects of radolmidine in different models of acute and chronic pain. Dexmedetomidine and saline served as controls. Male Sprague‐Dawley rats were studied in acute pain (tail flick), carrageenan inflammation, and the spinal nerve ligation model of neuropathic pain. Mechanical allodynia was assessed with von Frey filaments, cold allodynia with the acetone test, and thermal hyperalgesia with the paw flick test. Locomotor activity‐vigilance was assessed in a dark field. Dexmedetomidine and radolmidine were administered intrathecally in doses of 0.25 μg, 2.5 μg, and 10 μg. In the tail flick test, radolmidine showed a dose‐dependent antinociceptive effect, being equipotent compared with dexmedetomidine. In carrageenan inflammation, intrathecal doses of 2.5 μg or 5 μg of dexmedetomidine/radolmidine produced significant antinociception compared with saline (P < 0.01). The two drugs were equianalgesic. In the neuropathic pain model, an intrathecal dose of 5 μg dexmedetomidine‐radolmidine had a significant antiallodynic effect compared with saline (P < 0.01). The 2 drugs were equipotent. Intrathecal administration of both dexmedetomidine and radolmidine dose dependently decreased spontaneous locomotor activity‐vigilance, but this effect was significantly smaller after intrathecal administration of radolmidine than after intrathecal dexmedetomidine. Conclude radolmidine and dexmedetomidine had equipotent antinociceptive effects in all tests studied. However, radolmidine caused significantly less sedation than dexmedetomidine, probably because of a different pharmacokinetic profile.
Basic Science (33)
Authors: Zhang Jun‐Ming , Li Huiqing , Brull Sorin J.
Published: September 2010

Perfusion of the mechanically compressed lumbar ganglion with lidocaine reduces mechanical hyperalgesia and allodynia in the rat. (University of Arkansas for Medical Sciences, Little Rock, AR) J Neurophysiol 2000;84:798–805.

This study used an animal model of lumbar radiculopathy to investigate the neurological mechanisms of cutaneous hyperalgesia and tactile allodynia. The rat L5 dorsal root ganglion (DRG) was chronically compressed by inserting a hollow perforated rod into the intervertebral foramen. The DRG was constantly perfused through the hollow rod with either lidocaine or normal saline delivered by a subcutaneous osmotic pump. Behavioral evidence for neuropathic pain after DRG compression involved measuring the incidence of hindlimb withdrawals to both punctate indentations of the hind paw with mechanical probes exerting different bending forces and to light stroking of the hind paw with a cotton wisp. Behavioral results showed that for saline‐treated control rats: the withdrawal thresholds for the ipsilateral and contralateral paws to mechanical stimuli decreased significantly after surgery and the incidence of foot withdrawal to light stroking significantly increased on both ipsilateral and contralateral hind paws. Local perfusion of the compressed DRG with 2% lidocaine for 7 days at a low flow‐rate (1 μl/h), or for 1 day at a high flow‐rate (8 μl/h) partially reduced the decrease in the withdrawal thresholds on the ipsilateral foot, but did not affect the contralateral foot. The incidence of foot withdrawal in response to light stroking with a cotton wisp decreased significantly on the ipsilateral foot and was completely abolished on the contralateral foot in the lidocaine treatment groups. Conclude that compression of the L5 DRG induced central pain syndrome that included bilateral mechanical hyperalgesia and tactile allodynia. Results also suggest that a lidocaine block, or a reduction in abnormal activity from the compressed ganglia to the spinal cord, could partially reduce mechanical hyperalgesia and tactile allodynia.

Comments by Marshall Devor, PhD.

Tonic compression of the dorsal root ganglion (DRG) in animal preparations, and presumably also in man, causes sensory cells to become electrically hyperexcitable. The resulting spontaneous discharge is a cause of ongoing paresthesias and pain. Many believe that in addition, this ectopic activity can trigger and maintain central sensitization in the spinal cord, resulting in tactile hypersensitivity (allodynia and hyperalgesia) in the body parts innervated by the ganglion. This second effect of ectopic DRG activity, however, is controversial. Zhang and collaborators now provide strong new support for this idea by showing that lidocaine infusion into the DRG, with consequent block of the ectopic DRG firing, considerably reduces allodynia and hyperalgesia for the duration of the infusion (weeks). Here is a novel therapeutic approach that deserves a try.
Headache (45)
Authors: Schulman Elliot A. , Cady Roger K. , Henry Dan
Published: September 2010

Effectiveness of sumatriptan in reducing productivity loss due to migraine: results of a randomized, double blind, placebo‐controlled clinical trial. (Center for Headache Management, Springfield, PA) Mayo Clin Proc 2000;75:782–789.

This clinical trial determined the effect of sumatriptan on migraine‐related workplace productivity loss. Adult migraine sufferers self‐injected 6 mg of sumatriptan or matching placebo to treat a moderate or severe migraine within the first 4 h of a minimum of an 8‐h work shift. Outcome measures included productivity loss and number of patients returning to normal work performance 2 h after injection and across the work shift, time to return to normal work performance, and time to headache relief. A total of 206 patients underwent screening, 140 (safety population) of whom returned for clinic treatment. Of these 140 patients, 119 received migraine treatment in the workplace. Sumatriptan treatment tended to reduce median productivity loss 2 h after injection compared with placebo (25.2 versus 29.9 min, respectively) (P = 0.14). Significant reductions in productivity loss were obtained across the work shift after sumatriptan treatment compared with placebo (36.8 versus 72.6, respectively) (P = 0.001). Significantly more sumatriptan‐treated patients versus placebo‐treated patients experienced shorter return to normal work performance at 2 h and across the work shift. Significantly more sumatriptan‐treated patients experienced headache relief 1 h after injection compared with placebo‐treated patients. Conclude that across an 8‐h work shift, sumatriptan was superior to the placebo in reducing productivity loss due to migraine.
Neurology (55)
Authors: Dworkin Robert H. , Perkins Frederick M. , Nagasako Elna M.
Published: September 2010

Prospects for the prevention of postherpetic neuralgia in herpes zoster patients. (University of Rochester School of Medicine and Dentistry, Rochester, NY) Clin J Pain 2000;16:S90–100.

This review discussed the results of recent studies that have identified risk factors for the development of postherpetic neuralgia (PHN) and have implicated several peripheral and central mechanisms in its pathophysiology. These risk factors and mechanisms of PHN provide a basis for hypothesizing that combining antiviral therapy with analgesic treatment beginning as soon as possible after the onset of herpes zoster would reduce the risk of PHN beyond that achieved by antiviral therapy alone. Conclude this treatment approach would be expected to reduce the risk of PHN in herpes zoster patients by attenuating acute pain and thereby preventing the initiation of central mechanisms of chronic pain.
Neurology (56)
Authors: Backonja Misha‐Miroslav
Published: September 2010

Anticonvulsants (antineuropathies) for neuropathic pain syndromes. (University of Wisconsin Hospital and Clinics, Madison, WI) Clin J Pain 2000;16:S67–72.

This review concentrated on randomized clinical trials of anticonvulsants for neuropathic pain syndromes. The discussion included the use of phenytoin, benzodiazepines, valproic acid, lamotrigine, and gabapentin (GBP). GBP has a favorable side effects profile, and based on the results of these studies, it should be considered a first‐line treatment for neuropathic pain. GBP mechanisms of action are still not thoroughly defined, but GBP is effective in relieving indexes of allodynia and hyperalgesia in animal models. It still remains to be seen whether GBP is as effective in other painful disorders. One small clinical trial with lamotrigine demonstrated improved pain control in trigeminal neuralgia. Evidence in support of the efficacy of anticonvulsant drugs in the treatment of neuropathic pain continues to evolve, and benefits have been clearly demonstrated in the case of GBP and carbamazepine. More advances in our understanding of the mechanisms underlying neuropathic pain syndromes should further our opportunities to establish the role of anticonvulsants in the treatment of neuropathic pain.

Comment by Enrique Reig, MD.

The clinical efficacy of anticonvulsants is clearly established after years of use in patients with chronic neuropathic pain. However, there are few controlled studies to support their clinical efficacy. Not all anticonvulsant drugs have the same mode of action, which explains why their relief of the different symptoms of neuropathic pain (allodynia, hyperalgesia, burning pain, etc.) is varied. Gabapentine is a first‐choice drug for relieving allodynia and hyperalgesia, but it is usually less effective for decreasing paresthesia and dysaesthesia.

This article does not refer to clonazepam (a benzodiazepine acting on GABA, which is useful in stabbing pain) or topiramate. The latter is an antiepileptic drug with a good profile for the treatment of neuropathic pain. It has a triple action mechanism: Na+ channel blockade, increased GABA transmission, and antagonism of the kainate‐glutamate/AMPA.
Neurology (58)
Authors: Baron Ralf
Published: September 2010

Peripheral neuropathic pain: from mechanisms to symptoms. (Christian‐Albrechts‐Univerität Kiel, Kiel, Germany) Clin J Pain 2000;16:S12–20.

This review concentrates on the several independent pathophysiological mechanisms in both the peripheral and central nervous system that are responsible for sensory symptoms as well as spontaneous and evoked pains in peripheral neuropathies. These mechanisms can operate in concert in a single disease entity and also in a single patient. Distinct pathophysiological mechanisms lead to specific sensory symptoms, for example, dynamic mechanical allodynia and cold hyperalgesia. It is also possible that the pain‐generating mechanism and the symptoms change during the course of the disease. A thorough analysis of sensory symptoms may reveal the underlying mechanisms that are mainly active in a particular patient. The treatment of neuropathic pain is currently unsatisfactory. In the future, drugs will be developed that address specifically the relevant combination of mechanisms.

Comment by Enrique Reig, MD.

This is an excellent article, which will be a landmark in the approach to the treatment of neuropathic pain. There are several pathophysiological mechanisms, which can cause sensitive symptoms and spontaneous or evoked pain. Mechanical or thermal hyperalgesia is caused by peripheral sensitization. Pinprick hyperalgesia is correlated to the “wind‐up” phenomenon. Allodynia has multiple triggering factors: central sensitization, central reorganization and loss of inhibitory control. Paresthesia is explained by ectopic discharges due to the accumulation of Na+ channels, as with stabbing or paroxysmal pain. A hot or burning pain can be explained by peripheral sensitization and loss of inhibitory mechanisms. This explains why not all painful syndromes respond with the same efficacy to a given treatment. Neuropathic pain can occur in very different forms. For instance, a diabetic neuropathy can be associated with allodynia and hyperalgesia, or with burning and paroxysmal pain. A different treatment is required for each of these symptoms. From now on, we must use a different criterion to label painful neuropathic syndromes. Keeping to the above example, we shall distinguish between diabetic neuropathy with allodynia and diabetic neuropathy with burning pain.
Neurosurgery (66)
Authors: Kemler Marius A. , Barendse Gerard A.M. , Van Kleef Maarten
Published: September 2010

Spinal cord stimulation in patients with chronic reflex sympathetic dystrophy. (Maastricht University Hospital, Maastricht, The Netherlands) N Engl J Med 2000;343:618–624.

This randomized trial involved patients who had had reflex sympathetic dystrophy for at least 6 months. Thirty‐six patients were assigned to receive treatment with spinal cord stimulation plus physical therapy, and 18 were assigned to receive physical therapy alone. The spinal cord stimulator was implanted only if test stimulation was successful. The intensity of pain was assessed (on a visual‐analogue scale from 0 cm [no pain] to 10 cm [very severe pain]), as well as the global perceived effect (on a scale from 1 [worst ever] to 7 [best ever]), functional status, and the health‐related quality of life. The test stimulation of the spinal cord was successful in 24 patients; the other 12 patients did not receive implanted stimulators. In an intention‐to‐treat analysis, the group assigned to receive spinal cord stimulation plus physical therapy had a mean reduction of 2.4 cm in the intensity of pain at 6 months, as compared with an increase of 0.2 cm in the group assigned to receive physical therapy alone (P < 0.001 for comparison between the 2 groups). In addition, the proportion of patients with a score of 6 (“much improved”) for the global perceived effect was much higher in the spinal cord stimulation group than in the control group (39% vs. 6%, P = 0.01). There was no clinically important improvement in functional status. The health‐related quality of life improved only in the 24 patients who actually underwent implantation of a spinal cord stimulator. Six of the 24 patients had complications that required additional procedures, including removal of the device in 1 patient. Conclude in carefully selected patients with chronic reflex sympathetic dystrophy, electrical stimulation of the spinal cord can reduce pain and improve health‐related quality of life.

Conmment by R. Ruiz‐López, MD.

This is a well‐written article describing a prospective, randomized, controlled trial of spinal cord stimulation (SCS) for reflex sympathetic dystrophy, which is also known as complex regional pain syndrome type I (CRPS I). The results show clearly that in carefully selected patients suffering from this pain syndrome, SCS can reduce pain and improve health‐related quality of life compared to patients treated only with physical therapy. Functional status did not improve in either group of patients as SCS treats pain, but not the disease itself. The authors note that the improvement in the overall score for health‐related quality of life was derived mainly from the alleviation of pain as in the study population, pain was the primary source of distress. This study represents a major reference for pain doctors and neurosurgeons treating CRPS and chronic pain.
Pharmacology (81)
Authors: Abs Roger , Verhelst Johan , Maeyaert Jan
Published: September 2010

Endocrine consequences of long‐term intrathecal administration of opioids. (University of Antwerp, Edegem, Belgium) J Clin Endocrinol Metab 2000;85:2215–2222.

This study involved 73 patients (29 men and 44 women) receiving opioids intrathecally for nonmalignant pain who were enrolled for extensive endocrine investigation. At the time of hormonal determination, the mean duration of opioid treatment was 26.6 ± 16.3 months; the mean daily dose of morphine was 4.8 ± 3.2 mg. The control group consisted of 20 patients (11 men and 9 women) with a comparable pain syndrome, but not treated with opioids. Decreased libido or impotency was present in 23 of 24 men receiving opioids. The serum testosterone level was below 9 nmol/L in 25 of 29 men and was significantly lower than that in the control group (P < 0.001). The free androgen index was below normal in 18 of 29 men and was significantly lower than that in the control group (P < 0.001). The serum LH level was less than 2 U/L in 20 of 29 men and was significantly lower than that in the control group (P < 0.001). Serum FSH was comparable in both groups. Decreased libido was present in 22 of 32 women receiving opioids. All 21 premenopausal females developed either amenorrhea or an irregular menstrual cycle, with ovulation in only 1. Serum LH, estradiol, and progesterone levels were lower in the opioid group. In all 18 postmenopausal females significantly decreased serum LH (P < 0.001) and FSH (P = 0.012) levels were found. The 24‐h urinary free cortisol excretion was below 20 μg/day in 14 of 71 opioid patients and was significantly lower than that in the control group (P = 0.003). The peak cortisol response to insulin‐induced hypoglycemia was below 180 μg/L in 9 of 61 opioid patients and was significantly lower than that in the nonopioid group (P = 0.002). The insulin‐like growth factor I sd score was below −2 sd in 12 of 73 opioid patients and was significantly lower than that in the control group (P = 0.002). The peak GH response to hypoglycemia was below 3 μg/L in 9 of 62 subjects and was significantly lower than that in the control group (P = 0.010). Thyroid function tests and PRL levels were considered normal. No metabolic disturbances were recorded, apart from significantly decreased high‐density lipoprotein cholesterol levels (P = 0.041) and elevated total/high density lipoprotein cholesterol ratio (P = 0.008) in the opioid group compared to the control group. Supplementation with gonadal steroids improved sexual function in most patients. Conclude of all patients receiving intrathecal opioids, the large majority of men and all women developed hypogonadotropic hypogonadism, about 15% developed central hypocorticism, and about 15% developed GH deficiency. These findings suggest that further investigations are required to determine the need for systematic endocrine work‐up in these patients and the necessity for substitutive therapy.
Pharmacology (83)
Authors: Warren P.M. , Taylor J.H. , Nicholson K.E. , Wraith P.K. , Drummond: G.B.
Published: September 2010

Influence of tramadol on the ventilatory response to hypoxia in humans. (University of Edinburgh, Edinburgh, United Kingdom) Br J Anaesth 2000;85:211–216.

In this study, the effect of tramadol on the ventilatory response to 7 min acute isocapnic hypoxia during steady mild hypercapnia in 14 healthy volunteers (7 male, 7 female) was studied. The acute hypoxic response was measured before and 1 h after oral placebo or tramadol (100 mg). After tramadol, ventilation during mild hypercapnia (mean 11.28 liters min−1) was significantly less (P < 0.05) than during placebo baseline (13.93 liters min−1), tramadol baseline (14.63 liters min−1), or after placebo (14.9 liters min−1), confirming that tramadol has a small depressive effect on the hypercapnic ventilatory response. There was no significant difference in the hypoxic ventilation/Spo2 response measured during the placebo baseline (0.99), placebo (1.18), tramadol baseline (0.78) or tramadol (0.68) runs. These data suggest that tramadol does not depress the hypoxic ventilatory response.
Physical Medicine and Rehabilitation (88)
Authors: Suputtitada: A.
Published: September 2010

Managing spasticity in pediatric cerebral palsy using a very low dose of botulinum toxin type A: preliminary report. (Chulalongkorn University Hospital, Bangkok, Thailand) Am J Phys Med Rehabil 2000;79:320–326.

This study was conducted to determine if very low doses of botulinum toxin type A (BTX‐A) could reduce spasticity and improve gait in cerebral palsied children when combined with rehabilitation therapy. The trainable (IQ> 80), ambulatory, spastic diplegic or hemiplegic cerebral palsied children, with no fixed contractures in at least one limb, were selected for this study. Patients with a score of 3 on a modified Ashworth scale received 0.5 units of BTX‐A/kg/muscle. Patients with an Ashworth score of 4 received 1.0 BTX‐A/kg/muscle. After BTX‐A injection, all patients received rehabilitation therapy and plastic ankle and foot orthoses for walking. Both groups exhibited improvement in Ashworth score and in gait within 72 h of injection with botulinum toxin. Beneficial effects persisted for 10 to 12 months in most patients, with 3 patients exhibiting benefits for at least 20 months. Conclude that a very low dose of BTX‐A combined with rehabilitation therapy resulted in a long‐lasting decrease in spasticity and an improvement in gait in children with cerebral palsy.
Physical Medicine and Rehabilitation (89)
Authors: Slipman Curtis W. , Lipetz Jason S. , Herzog Richard J. , Vresilovic: Edward J.
Published: September 2010

Nonsurgical treatment for radicular pain of zygoapophyseal joint cyst origin: therapeutic selective nerve root block. (Hospital of the University of Pennsylvania, Philadelphia, PA) Arch Phys Med Rehabil 2000;81;1119–1122.

This report discusses the first case of zygoapophyseal joint cyst‐induced radicular pain successfully treated with therapeutic selective nerve root block. A 56‐year‐old dentist presented with pain involving the lateral thigh, lateral calf, and foot dorsum that worsened with standing and walking. Magnetic resonance imaging of the lumbar spine showed a cyst emanating from the right L4‐L5 zygoapophyseal joint, resulting in central canal and lateral recess stenosis. The patient was treated with 2 fluoroscopically guided therapeutic L5 selective nerve root blocks. The patient remained pain free at 18‐month follow‐up.
Safety and Efficacy of the Infraclavicular Nerve Block Performed at Low Current
Authors: Keschner Mitchell T. , Michelsen Heidi , Rosenberg Andrew D. , Wambold Daniel , Albert David B. , Altman Robert , Green Steven , Posner Martin
Published: September 2010

Abstract:  It has recently been suggested that peripheral nerve or plexus blocks performed with the use of a nerve stimulator at low currents (<0.5 mA) may result in neurologic damage. We studied the infraclavicular nerve block, performed with the use of a nerve stimulator and an insulated needle, in a prospective evaluation of efficacy and safety. During a one‐year period, 248 patients undergoing infraclavicular nerve block were evaluated for block success rate and incidence of neurologic complication. All blocks were performed with the use of a nerve stimulator and an insulated needle at ≤0.3 mA. Success rate was 94%, which increased to 96% with surgical infiltration of local anesthetic. There were no intraoperative or immediate postoperative complications noted. After one week, only one patient had a neurologic complaint, and this was surgically related, referable to surgery performed on the radial nerve. We conclude that infraclavicular nerve blocks performed at low currents (≤0.3 mA) are safe and effective.
Decreased Pain and Improved Quality of Life in Fibromyalgia Patients Treated with Olanzapine, an Atypical Neuroleptic
Authors: Freedenfeld Robert N. , Murray Michelle , Fuchs Perry N. , Kiser R. Sanford
Published: September 2010

Abstract: Fibromyalgia is a significant clinical problem associated with generalized pain and significant interference with daily activities. Although a variety of treatment modalities have been utilized, clinicians have struggled to find an effective means of treatment. Therefore, this study assessed the efficacy of the atypical neuroleptic olanzapine for the treatment of fibromyalgia symptoms. To examine the efficacy of olanzapine for the treatment of fibromyalgia symptoms, the charts of 51 patients treated with olanzapine were evaluated for improvements in pain and daily life functioning. At the time of initial assessment, patients had been diagnosed with a variety of medical and psychiatric disorders and a history of neuroleptic treatment. Pain was widespread and characteristic of pain associated with fibromyalgia. Pretreatment ratings on pain and the interference scales averaged 6.54–8.69 on a 0–10 scale. Post‐treatment ratings on the same scales revealed significant improvement on virtually all scales. The benefits of olanzapine to improve fibromyalgia symptoms must, however, be carefully considered because there were a variety of side effects (i.e., weight gain, somnolence/sedation) that were of sufficient strength to cause a number of patients to discontinue treatment. In general, the data provide strong support that olanzapine can, in certain patients, improve symptoms associated with fibromyalgia in patients who have had limited success with other treatment modalities.