Tackling multi-pollutant multi-effect problems--an iterative approach

Within both the UN ECE and the European Union, there has been a strong move towards the so-called multi-pollutant multi-effect approach to air pollution strategies. In this approach a number of pollutants are considered, and emission reductions are determined after looking at the effect of each of these pollutants on a number of environmental problems. This new approach is very ambitious and raises a number of problems in balancing the effects and costs of different emission reductions against achieved environmental benefits. We describe an iterative method designed for addressing such multi-pollutant multi-effect type problems. In the examples given here, the method is used to estimate combinations of NOx and VOC emission reductions from all European countries so as to reduce environmental problems associated with acidification and ozone in a cost-effective manner. The iterative technique is designed to be flexible and transparent, so that a number of different approaches to multi-pollutant-multi-effect problems can be considered. This technique can be used to provide early guidance on various control strategy options, and allows rapid exploration of the many targets and measures possible with these approaches. It also demonstrates how even complex multi-dimensional environmental problems may be amenable to understandable solutions.

Organophosphate neuropathy due to methamidophos: biochemical and neurophysiological markers

Neuropathy target esterase (NTE), the putative target enzyme for organophosphate induced delayed polyneuropathy (OPIDP), can be measured in lymphocytes but has rarely been assessed in acute human poisoning. Serum autoantibodies to nervous system proteins develop in hens poisoned with neuropathic insecticides and also have not been studied after human poisoning. Serial lymphocyte NTE (LNTE) was measured in a 16-year-old boy after acute poisoning with methamidophos for evaluation as a predictor of subsequent neuropathy. The profiles of serum autoantibodies to neurofilament triplet proteins, myelin basic protein, and glial fibrillary acidic protein were measured in order to characterize changes occurring as a result of OPIDP. Clinical neuropathy characterized by steppage gate and profound lower extremity weakness, decreased grip and pinch strength, and decreased ulnar and absent tibial compound muscle action potentials developed 2 weeks following poisoning. Sensory examination and nerve conduction studies were normal. On day 3 following poisoning LNTE was depressed (77% compared with subsequent baseline enzyme activity). Marked increases in serum immunoglobulin G (IgG) autoantibodies to glial fibrillary acidic protein and to neurofilament 200 were observed after the development of OPIDP. We conclude that inhibition of lymphocyte NTE is predictive of subsequent OPIDP. Serum autoantibody titers to nervous system proteins may be useful markers of neuropathy.

Acquisition of surgical skills: a randomized trial of didactic, videotape, and computer-based training

BACKGROUND

Although computer-based training (CBT) can enhance didactic instruction, few studies have assessed the efficacy of CBT for basic surgical skills training. This study compares CBT with traditional methods of basic surgical skills training.

METHODS

Sixty-nine naive medical students were randomized into 3 treatment groups for basic surgical skills instruction: didactic, videotape, or CBT. All instructional material contained the same pictures, text, and audio. With use of a multiple-choice question examination and a series of performance stations, students were objectively assessed before, immediately after, and 1 month after skills instruction. Raters were blinded to treatment modality during the follow-up evaluation.

RESULTS

There were no significant differences among the groups before treatment. After treatment, the didactic group scored higher on the multiple-choice question examination. In contrast, the videotape and CBT groups demonstrated statistically significant (P < .01) enhancement of technical skills compared with the didactic group. After 1 month, a calculated performance quotient revealed statistically significant (P < .01) improvement only in the CBT group. The amount of time students spent practicing their skills was not significantly different among the groups.

CONCLUSIONS

CBT is as effective as, and possibly more efficient, than traditional methods of basic surgical skills training for medical students.

How pediatric educators know what to teach: the use of teaching scripts

OBJECTIVE

Expert clinical teachers in medicine use teaching scripts. The aim of this study was to determine whether pediatricians also use common components of teaching scripts.

METHODS

Seventy-three pediatric clerkship directors identified anticipated errors and teaching points in response to two short vignettes. The content analysis of responses, which we completed, was analyzed by rank and receipt of teaching awards.

RESULTS

Greater than 87% of respondents identified at least one of three anticipated learner errors and greater than 80% of respondents identified at least one of three to four teaching points. Teaching points related directly to anticipated errors in 60% of responses. Level of experience and receipt of teaching awards had no impact on response content.

CONCLUSIONS

Consistent with findings on the use of teaching scripts, pediatrics' educators achieved high congruence on anticipated errors and teaching points on two teaching vignettes. These findings support the hypothesis that developing teaching expertise is associated with other script components.

3-nitropropionic acid oxidase from horseshoe vetch (Hippocrepis comosa): a novel plant enzyme

A novel enzyme that catalyses the oxygen-dependent oxidation of 3-nitropropionic acid (3NPA) to malonate semialdehyde, nitrate, nitrite and H2O2 has been purified from leaf extracts of the horseshoe vetch, Hippocrepis comosa, and named 3NPA oxidase. The enzyme is a flavoprotein with a subunit molecular mass of 36 kDa containing 1 molecule of FMN and exhibits little specificity for all nitroalkanes tested other than 3NPA (apparent Km 620 microM). The maximum enzyme activity in vitro was expressed at pH4.8 and was inhibited strongly by the products nitrate and nitrite. 3NPA oxidase activity was detected in green shoots, which also contain high concentrations of 3NPA, from plants grown with nitrate, ammonium or N2 as sources of nitrogen. Enzyme activity was absent from roots and cell cultures, neither of which accumulate high levels of 3NPA.

Neuromuscular blockers

The use of corrosive, injectable neuromuscular blockers has been a treatment option for many years; however, the more recent advent of botulinum toxin (BTX) treatment has revived interest in localized treatments. This article reviews the use of local anesthetics, alcohol, phenol, and BTX treatment for localized muscular overactivity syndromes.

Releasing resources for reinvestment in health gain

The National Health Services in Wales has adopted a strategic approach based on health gain. Five approaches to meeting this problem are considered (i) eliminating basic inefficiencies; (ii) eliminating unnecessary clinical activity; (iii) doing what is done now but differently; (iv) investing now to save later and (v) withdrawing from a particular area of activity, because it is less important than other competing claims. Each of these is briefly considered with particular reference to the Welsh situation. Three particular lines of advance are identified to achieve the above: creating new sources of information; working more effectively across organisational boundaries; and making the cultural changes to make it all possible.

Ebola (subtype Reston) virus among quarantined nonhuman primates recently imported from the Philippines to the United States

In April 1996, laboratory testing of imported nonhuman primates (as mandated by quarantine regulations) identified 2 cynomolgus macaques (Macaca fascicularis) infected with Ebola (subtype Reston) virus in a US-registered quarantine facility. The animals were part of a shipment of 100 nonhuman primates recently imported from the Philippines. Two additional infected animals, who were thought to be in the incubation phase, were identified among the remaining 48 animals in the affected quarantine room. The other 50 macaques, who had been held in a separate isolation room, remained asymptomatic, and none of these animals seroconverted during an extended quarantine period. Due to the rigorous routine safety precautions, the facility personnel had no unprotected exposures and remained asymptomatic, and no one seroconverted. The mandatory quarantine and laboratory testing requirements, put in place after the original Reston outbreak in 1989-1990, were effective for detecting and containing Ebola virus infection in newly imported nonhuman primates and minimizing potential human transmission.

Modelling photochemical oxidant formation, transport, deposition and exposure of terrestrial ecosystems

The chemical processes responsible for production of photochemical oxidants within the troposphere have been the subject of laboratory and field study throughout the last three decades. During the same period, models to simulate the atmospheric chemistry, transport and deposition of ozone (O(3)) from individual urban sources and from regions have been developed. The models differ greatly in the complexity of chemical schemes, in the underlying meteorology and in spatial and temporal resolution. Input information from land use, spatial and temporally disaggregated emission inventories and meteorology have all improved considerably in recent years and are not fully implemented in current models. The development of control strategies in both North America and Europe to close the gaps between current exceedances of environmental limits, guide values, critical levels or loads and full compliance with these limits provides the focus for policy makers and the support agencies for the research. The models represent the only method of testing a range of control options in advance of implementation. This paper describes currently applied models of photochemical oxidant production and transport at global and regional scales and their ability to simulate individual episodes as well as photochemical oxidant climatology. The success of current models in quantifying the exposure of terrestrial surfaces and the population to potentially damaging O(3) concentrations (and dose) is examined. The analysis shows the degree to which the underlying processes and their application within the models limit the quality of the model products.

A randomized trial of amitriptyline and mexiletine for painful neuropathy in HIV infection. AIDS Clinical Trial Group 242 Protocol Team

BACKGROUND

Painful sensory neuropathy is a common complication of HIV infection. Based on prior uncontrolled observations, we hypothesized that amitriptyline or mexiletine would improve the pain symptoms.

METHOD

A randomized, double-blind, 10-week trial of 145 patients assigned equally to amitriptyline, mexiletine, or matching placebo. The primary outcome measure was the change in pain intensity between baseline and the final visit.

RESULTS

The improvement in amitriptyline group (0.31+/-0.31 units [mean+/-SD]) and mexiletine group (0.23+/-0.41) was not significantly different from placebo (0.20+/-0.30). Both interventions were generally well tolerated.

CONCLUSIONS

Neither amitriptyline nor mexiletine provide significant pain relief in patients with HIV-associated painful sensory neuropathy.

Buchu--South Africa's amazing herbal remedy

Buchu leaves and oil of buchu were used by the indigenous people of South Africa for hundreds of years. The medicinal use of buchu was taken up by the early Dutch settlers and later introduced into the pharmaceutical industry in the UK. Buchu preparations are now used as a diuretic and for a wide range of conditions including stomach aches, rheumatism, bladder and kidney infections and coughs and colds.

A cysteine endopeptidase with a C-terminal KDEL motif isolated from castor bean endosperm is a marker enzyme for the ricinosome, a putative lytic compartment

A papain-type cysteine endopeptidase with a molecular mass of 35 kDa for the mature enzyme, was purified from germinating castor bean (Ricinus communis L.) endosperm by virtue of its capacity to process the glyoxysomal malate dehydrogenase precursor protein to the mature subunit in vitro (C. Gietl et al., 1997, Plant Physiol 113: 863-871). The cDNA clones from endosperm of germinating seedlings and from developing seeds were isolated and sequence analysis revealed that a very similar or identical peptidase is synthesised in both tissues. Sequencing established a presequence for co-translational targeting into the endoplasmic reticulum, an N-terminal propeptide and a C-terminal KDEL motif for the castor bean cysteine endopeptidase precursor. The 45-kDa pro-enzyme stably present in isolated organelles was enzymatically active. Immunocytochemistry with antibodies raised against the purified cysteine endopeptidase revealed highly specific labelling of ricinosomes, organelles which co-purify with glyoxysomes from germinating Ricinus endosperm. The cysteine endopeptidase from castor bean endosperm, which represents a senescing tissue, is homologous to cysteine endopeptidases from other senescing tissues such as the cotyledons of germinating mung bean (Vigna mungo) and vetch (Vicia sativa), the seed pods of maturing French bean (Phaseolus vulgaris) and the flowers of daylily (Hemerocallis sp.).

A phase I/II trial of nimodipine for HIV-related neurologic complications

BACKGROUND

Few effective treatments are available for AIDS dementia complex (ADC) and HIV-associated neuropathy. However, recent in vitro studies indicate that nimodipine, a voltage-dependent calcium channel antagonist, can prevent HIV-related neuronal injury and may provide a novel form of treatment for these disorders.

METHODS

To determine the safety and possible efficacy of this agent, 41 patients with mild to severe ADC, including 19 patients with neuropathy, were entered into the AIDS Clinical Trial Group multicenter, phase-I and phase-II study. Nimodipine at 60 mg p.o., five times daily; 30 mg p.o., three times daily; or placebo was administered for 16 weeks as adjuvant treatment to antiretroviral therapy.

RESULTS

Neuropsychological performance at baseline, measured by the composite neuropsychological Z score (NPZ-8), correlated significantly with the ADC stage and with CSF levels of neopterin, a marker of immune activation. No significant differences in toxicity were observed among the three arms. Intent-to-treat analysis showed no significant change in the NPZ-8, although improvement was suggested in the high-dose arm. In addition, a trend toward stabilization in peripheral neuropathy was observed in both nimodipine arms compared with placebo.

CONCLUSIONS

Nimodipine and other similar nonantiretroviral agents may provide a safe and promising avenue of treatment for neurologic disorders associated with HIV infection. The results of this study indicate that further clinical trials are warranted.

Small bowel obstruction caused by a dislodged biliary stent

Biliary stents are commonly used in the management of obstructive jaundice. Complications at the time of insertion are not uncommon, but late complications due to dislodged stents have not been previously reported.

Failure of cytarabine in progressive multifocal leukoencephalopathy associated with human immunodeficiency virus infection. AIDS Clinical Trials Group 243 Team

BACKGROUND

Progressive multifocal leukoencephalopathy affects about 4 percent of patients with the acquired immunodeficiency syndrome (AIDS), and survival after the diagnosis of leukoencephalopathy averages only about three months. There have been anecdotal reports of improvement but no controlled trials of therapy with antiretroviral treatment plus intravenous or intrathecal cytarabine.

METHODS

In this multicenter trial, 57 patients with human immunodeficiency virus (HIV) infection and biopsy-confirmed progressive multifocal leukoencephalopathy were randomly assigned to receive one of three treatments: antiretroviral therapy alone, antiretroviral therapy plus intravenous cytarabine, or antiretroviral therapy plus intrathecal cytarabine. After a lead-in period of 1 to 2 weeks, active treatment was given for 24 weeks. For most patients, antiretroviral therapy consisted of zidovudine plus either didanosine or stavudine.

RESULTS

At the time of the last analysis, 14 patients in each treatment group had died, and there were no significant differences in survival among the three groups (P=0.85 by the log-rank test). The median survival times (11, 8, and 15 weeks, respectively) were similar to those in previous studies. Only seven patients completed the 24 weeks of treatment. Anemia and thrombocytopenia were more frequent in patients who received antiretroviral therapy in combination with intravenous cytarabine than in the other groups.

CONCLUSIONS

Cytarabine administered either intravenously or intrathecally does not improve the prognosis of HIV-infected patients with progressive multifocal leukoencephalopathy who are treated with the antiretroviral agents we used, nor does high-dose antiretroviral therapy alone appear to improve survival over that reported in untreated patients.

Ontogenesis of lateralized rotational behavior in hamsters: a time series study

This is a longitudinal study of the postnatal development of lateralized rotational behavior. Hamsters (n = 75) were tested for spontaneous rotational behavior in cylindrical arenas, from P2 (P1 = day of birth) to P60. A daily laterality index was calculated for each animal, of which the averages and standard deviations were used to follow the animals' lateralized behavior. A strong variability between and within animals appeared throughout development, with a tendency to the right side in most animals, which declined after the first postnatal week. No oscillatory cycles were identified. To study patterns of development, the series were divided into four periods and the animals were separated into five groups. The laterality indexes of all four periods were significantly different between the groups. A total of 79% of the animals showed consistent behavior along development: either a preference to one side (20% left, 26% right), or no preference at all (33%). The remaining animals changed preference during development. Only a few animals remained strongly lateralized throughout the 60 days, most of them showing a slight, non-significant preference after P10. Results suggest an ontogenetic decrease in lateralization of this behavior that could in part be explained by the maturation of an interhemispheric regulatory system.

HIV rounds at Cornell: selected neurologic complications of HIV disease

Neurological disorders are among the most frequent and devastating complications of HIV infection and AIDS. As patients survive longer with the availability of highly active anti-retrovital therapy, it is likely that the frequency of some of these disorders will increase, since patients will survive long enough to develop them. The central and peripheral nervous system may be affected by numerous primary and secondary complications. These neurological disorders include HIV dementia, primary CNS lymphoma, toxoplasmosis, progressive multifocal leukoencephalopathy, vacuolar myelopathy, peripheral neuropathies, and myopathy. In this review we discuss current thoughts on clinical features, pathogenesis, diagnostic evaluation, treatment and clinical trials in several of these HIV-associated neurologic disorders.

Possible toxicity of herbal remedies

Herbal remedies are rapidly gaining popularity throughout the world as a result of dissatisfaction with conventional medicines. It is a widely held belief that herbal preparations are "natural" and are therefore intrinsically harmless. However, their effects can be very powerful and potentially lethal if used incorrectly and their use as a substitute for conventional medicines may be ineffective. Toxic effects have been attributed to several factors including hepatotoxicity of main constituents, contamination of preparations by heavy metals or microorganisms, and adverse reactions due to age, and genetic and concomitant disease characteristics of the user.

Altered expression of tropomodulin in cardiomyocytes disrupts the sarcomeric structure of myofibrils

Tropomodulin is a tropomyosin-binding protein that terminates "pointed-end" actin filament polymerization. To test the hypothesis that regulation of tropomodulin:actin filament stoichiometry is critical for maintenance of actin filament length, tropomodulin levels were altered in cells by infection with recombinant adenoviral expression vectors, which produce either sense or antisense tropomodulin mRNA. Neonatal rat cardiomyocytes were infected, and sarcomeric actin filament organization was examined. Confocal microscopy indicated that overexpression of tropomodulin protein shortened actin filaments and caused myofibril degeneration. In contrast, decreased tropomodulin content resulted in the formation of abnormally long actin filament bundles. Despite changes in myofibril structure caused by altered tropomodulin expression, total protein turnover of the cardiomyocytes was unaffected. Biochemical analyses of infected cardiomyocytes indicated that changes in actin distribution, rather than altered actin content, accounted for myofibril reorganization. Ultrastructural analysis showed thin-filament disarray and revealed the presence of leptomeres after tropomodulin overexpression. Tropomodulin-mediated effects constitute a novel mechanism to control actin filaments, and our findings demonstrate that regulated tropomodulin expression is necessary to maintain stabilized actin filament structures in cardiac muscle cells.

Cerebellar degeneration associated with human immunodeficiency virus infection

Cerebellar disorders associated with HIV infection are typically the result of discrete cerebellar lesions resulting from opportunistic infections such as toxoplasmosis and progressive multifocal leukoencephalopathy or primary CNS lymphoma. Clinical symptoms and pathologic abnormalities related to the cerebellum may also be observed with HIV dementia. A primary cerebellar degeneration with HIV has not previously been reported. Ten patients were identified over an 8-year period at five medical centers. All patients had clinical, laboratory, and radiologic evaluations, and three had neuropathologic examinations. Patients presented with progressively unsteady gait, slurred speech, and limb clumsiness. Examination revealed gait ataxia, impaired limb coordination, dysarthria, and abnormal eye movements. Cognition, strength, and sensory function remained normal. CD4 lymphocyte counts varied between 10 and 437 cells/mm3. Neuroimaging studies showed prominent cerebellar atrophy. Neuropathology showed focal degeneration of the cerebellar granular cell layer and unusual focal axonal swellings in the brainstem and spinal cord. Cultures, histopathology, and immunochemical studies showed no conclusive evidence of infection. We report a syndrome of unexplained degeneration of the cerebellum occurring in association with HIV infection.

Carbohydrate deficient transferrin in detecting relapse in alcohol dependence

Patients reports together with findings at clinical examination and information from an informant such as a relative were used to categorise patients as relapsed or not relapsed during a 6 month period of out-patient treatment at an alcohol problems clinic. At each fortnightly visit, blood was taken for measurement of serum gamma-glutamyl transferase and carbohydrate deficient transferrin (Pharmacia method). A total of 53 patients attended for at least one follow-up visit. Mean CDT differentiated relapsers from non-relapsers at seven of the 11 visits (P < 0.05), but at no visit did mean GGT differentiate. CDT tended to become elevated after a relapse more quickly than GGT. However, whether using upper limit of normal (ULN), or defining a 'positive test' as > last test and either > 20% above lowest previous test or > ULN, specificity (averaged over the 11 visits) was greater for GGT than CDT. Some of the false positive results for CDT were in patients who, shortly after having a positive test, relapsed, suggesting that a rising CDT can herald a relapse admitted by the patient. This could not be shown for false positive GGT results. Inspection of individual trajectories of alcohol consumption and blood test results shows that for some patients GGT is the more effective marker of relapse, whilst for others CDT operates better.

Screening for drugs of abuse (II): Cannabinoids, lysergic acid diethylamide, buprenorphine, methadone, barbiturates, benzodiazepines and other drugs

Requirements for the provision of an efficient and reliable service for drugs of abuse screening in urine have been summarized in Part I of this review. The requirements included rapid turn-around times, good communications between requesting clinicians and the laboratory, and participation in quality assessment schemes. In addition, the need for checking/confirmation of positive results obtained for preliminary screening methods was stressed. This aspect of the service has assumed even greater importance with widespread use of dip-stick technology and the increasing number of reasons for which drug screening is performed. Many of these additional uses of drug screening have possible serious legal implications, for example, screening school pupils, professional footballers, parents involved in child custody cases, persons applying for renewal of a driving licence after disqualification for a drug-related offence, doctors seeking re-registration after removal for drug abuse, and checking for compliance with terms of probation orders; as well as pre-employment screening and work-place testing. In many cases these requests will be received from a general practitioner or drug clinic with no indication of the reason for which testing has been requested. This also raises the serious problems of a chain of custody, provision of two samples, stability of samples, and secure and lengthy storage of samples in the laboratory-samples may be requested by legal authorities several months after the initial testing. The need for confirmation of positive results is now widely accepted but it may be equally important to confirm unexpected negative results. Failure to detect the presence of maintenance drugs may lead to the patient being discharged from a drug treatment clinic and, if attendance at the clinic is one of the terms of continued employment, to dismissal. It seems likely that increasing abuse of drugs and the efforts of regulatory authorities to control this, will lead to the manufacture of more designer drugs. Production of substituted phenethylamines was facilitated by the drug makers' cook book, 'PIHKAL' (Phenethylamines I Have Known And Loved) by Dr Alexander Shulgin and Ann Shulgin, and production of substituted tryptamines is promised in their next book, TIHKAL. Looking to the future, laboratories will need to ensure that they can detect and quantitate an ever-increasing number of drugs and related substances. The question of confidence in results of drugs of abuse testing raised in 1993 by Watson has assumed even greater importance as a result of attention focused on the OJ Simpson trial in Los Angeles. Toxicological investigations are likely to be challenged more frequently in the future. Even if analyses have been performed by GC-MS, there is a need to establish the level of match between the spectrum of the unknown substance and a library spectrum which is considered acceptable for legal purposes. It will also be essential to ensure that computer libraries contain spectra for all substances likely to be encountered in drugs of abuse screening.

Genomic sequence analysis of a key residue (Arg183) in human G alpha q in invasive non-functional pituitary adenomas

OBJECTIVE

With isolated exceptions the only oncogene significantly associated with pituitary tumours is a constitutively active Gs protein (G alpha s). The recent cloning of the cDNA of human G alpha q has facilitated the study of this activator of the phospholipase C beta/Ca2+/ protein kinase C pathway. Since, with isolated exceptions, non-functional tumours are responsive in vitro to TRH and GnRH which activate Gq, we have investigated the genomic sequence of G alpha q, in non-functional (NF) invasive pituitary adenomas, at a residue corresponding to the one most frequently mutated in G alpha s.

PATIENTS AND MEASUREMENTS

We studied 27 invasive NF pituitary tumours by direct sequencing of DNA derived from archival slide extracted tumour cells. Primers were designed to encompass Arg183 (corresponding to Arg201 of G alpha s) which when mutated has been shown to have oncogenic potential when transfected into cultural rat fibroblasts. In a previous study we have described allelic loss at tumour suppressor gene loci (TSG) in 7 of these 27 tumours.

RESULTS

We successfully amplified genomic DNA with primers designed from the cDNA sequence of G alpha q with specific exclusion of a processed pseudogene. No mutations were found at Arg183, in either the tumours showing allelic losses at specific TSG loci, or in the 20 remaining tumours in which we found no losses at the TSG loci investigated.

CONCLUSIONS

Mutations at this key residue in G alpha q occur infrequently, if at all, in invasive non-functional pituitary tumours. However we cannot exclude the possibility of mutation(s) at the other key residue of G alpha q, Gin209, implicated in GTP hydrolysis, or in other components of this pathway.

Pharmacokinetics of N-acetylcysteine are altered in patients with chronic liver disease

BACKGROUND

The threshold plasma paracetamol concentration at which N-acetylcysteine (NAC) treatment is recommended to treat paracetamol poisoning in a patient with induced liver enzymes (for example, with chronic liver disease or taking anticonvulsant drugs) is 50% lower than in a patient without induced liver enzymes. More patients with chronic liver disease might therefore be expected to be exposed to NAC treatment than previously. In addition, there is increasing use of NAC in patients with chronic liver disease for multiorgan failure or hepatorenal syndrome. Little is known of NAC's pharmacokinetic properties in patients with cirrhosis.

AIM

The aim was to determine if the pharmacokinetics of NAC are altered by chronic liver disease.

SUBJECTS AND METHODS

NAC was given intravenously in a dose of 600 mg over 3 min to nine patients with biopsy-proven cirrhosis (Child's grade; 1 A, 4 B, 4 C: aetiology: 7 alcohol-related, 1 primary biliary cirrhosis, 1 secondary biliary stenosis) and six healthy matched controls. Venous blood was taken at 20, 40, 60 and 90 min then at 2, 3, 4, 6, 8 and 10 h after NAC administration. Serum NAC was estimated by HPLC. The data were normalized to a standard body weight of 70 kg.

RESULTS

The area under the serum concentration-time curve was increased (152.34 mg/L.h +/- 50.38 s.d.) in cirrhotics compared with normal controls (93.86 mg/L.h +/- 9.60 s.d.) (P < 0.05). The clearance of NAC was reduced in patients with chronic liver disease (4.52 L/h +/- 1.87 s.d.) compared with controls (6.47 L/h +/- 0.78: P < 0.01).

CONCLUSIONS

Increased vigilance for untoward anaphylactoid reactions is necessary in cirrhotics as they may have higher plasma NAC concentrations. Further studies to determine the optimum dosage regimen in such patients are required.

Paré as a neurosurgeon

The Cowlishaw Collection gives a splendid representation of the works of a Ambroise Paré (1510-1590). His Complete Works, in the great French edition edited by J.F. Malgaigne, are essential in any study of Paré's achievement, but the 1649 English edition provides a good basis for consideration of Paré's practice in what would now be termed neurosurgery. Paré had a large clinical experience in head injury management. His patients included Henri II King of France, who died from a penetrating orbital wound, and be described a number of other craniofacial wounds sustained in war or in warlike sports. His surgical instruments and operative techniques do not appear very innovative, but were doubtless good in their day; his methods of trephination compare favourably with those of the English surgeon John Woodall, his younger contemporary. He operated on head injuries and cranial infection, but had no capacity to treat intradural conditions, such as cerebral abscesses and tumours: his technical limitations are obvious, and the physicians on whom he had to rely could give him no guidance in neurological diagnosis. He was keenly interested in developmental malformations, and described several conditions that would now be referred to a paediatric neurosurgeon. Paré is of great historical importance as an outstanding Renaissance surgeon, whose influence extended throughout the literate world, and as far as Japan. With him, France replaced Italy and Spain in leadership in European surgical progress, a position that France retained at least until the age of Hunter.

Defining and evaluating quality for ambulatory care educational programs

As the training of medical students and residents increasingly moves to ambulatory care settings, clerkship and program directors must find a way to use their limited resources to guide the development and evaluation of the quality of these ambulatory-based learning experiences. To evaluate quality, directors must first define, in operational and measurable terms, what is meant by the term "quality" as it is applied to ambulatory-based education. Using educational theories and the definition of quality used by health care systems, the authors propose an operational definition of quality for guiding the planning, implementation, and evaluation of ambulatory care educational programs. They assert that quality is achieved through the interaction of an optimal learning environment, defined educational goals and positive outcomes, participant satisfaction, and cost-effectiveness. By describing the components of quality along with examples of measurable indicators, the authors provide a foundation for the evaluation and improvement of instructional innovations in ambulatory care education for the benefit of teachers, learners, and patients.

Strategies for efficient and effective teaching in the ambulatory care setting

Medical education in the ambulatory care setting is characterized in part by the question of how to ensure educational effectiveness while simultaneously providing high-quality, cost-effective patient care. The constraints associated with managed care have only served to escalate the intensity of this dilemma. However, in spite of the difficulties faced by ambulatory care preceptors, there are educationally sound and time-efficient strategies clinical teachers may employ to improve ambulatory care education. Emphasizing the basic three-step process of planning, teaching, and reflection, the authors describe five such strategies: "wave" scheduling, orienting learners to patients, having learners do their case presentations in the examination room, employing the microskills of the "one-minute preceptor," and effectively reflecting on one's teaching in order to develop effective teaching scripts. Research in ambulatory care learning has indicated that learners must be given significant roles in patient care and that preceptors must observe trainees as they care for patients so that they can provide trainees with helpful feedback. Employing these strategies in the ambulatory care setting will help educators to accomplish these two objectives while minimizing disruption to cost-effective, high-quality clinical practice.

Future faculty development in family medicine

BACKGROUND AND OBJECTIVES

Several recurring conclusions about the changed conditions and future needs of faculty emerged from the articles in this dedicated issue. Faculty work is becoming more differentiated; time is increasingly constrained; and faculty are working in more diverse settings. Faculty reward structures and career ladders are changing, and acquiring additional competencies in new areas is essential. Although less then anticipated, there is some research to guide the development of programs to prepare faculty for these changes. Based on these conclusions, it is expected that in the future, faculty and program chairs will seek a tight match between what a faculty development effort addresses and the responsibilities of faculty participants and/or the goals of the department or program. The following trends are expected: 1) Regional/national comprehensive programs will often be the best choice for new faculty since many departments and residencies will not have sufficient resources to support their own faculty development programs. 2) Research-oriented faculty will be expected to devote 2 years or more to formal training. 3) Experienced faculty and department/program leaders, many of whom are graduates of our faculty development programs, will need advanced training in targeted areas, through on-site, contextualized education or through individualized programs--perhaps electronic. 4) Organizational development will be needed to help departments and programs make changes in missions and processes and to maintain a sense of community. At the same time that new models must be created to meet these future faculty development needs, support for such programs has decreased. Both local and national sources must be recommitted to support faculty development programs and research so we may advance our understanding of cost-effective approaches to faculty development. Funding agencies need to change their guidelines to match the current needs for development and limit funding to programs designed on evidence.