Turnovers of Sex-Determining Mutation in the Golden Pompano and Related Species Provide Insights into Microevolution of Undifferentiated Sex Chromosome

The suppression of recombination is considered a hallmark of sex chromosome evolution. However, previous research has identified undifferentiated sex chromosomes and sex determination by single SNP in the greater amberjack (Seriola dumerili). We observed the same phenomena in the golden pompano (Trachinotus ovatus) of the same family Carangidae and discovered a different sex-determining SNP within the same gene Hsd17b1. We propose an evolutionary model elucidating the turnover of sex-determining mutations by highlighting the contrasting dynamics between purifying selection, responsible for maintaining W-linked Hsd17b1, and neutral evolution, which drives Z-linked Hsd17b1. Additionally, sporadic loss-of-function mutations in W-linked Hsd17b1 contribute to the conversion of W chromosomes into Z chromosomes. This model was directly supported by simulations, closely related species, and indirectly by zebrafish mutants. These findings shed new light on the early stages of sex chromosome evolution.

Probiotics enhance resistance to Streptococcus iniae in Nile tilapia (Oreochromis niloticus) reared in biofloc systems

Biofloc technology is a rearing technique that maintains desired water quality by manipulating carbon and nitrogen and their inherent mixture of organic matter and microbes. Beneficial microorganisms in biofloc systems produce bioactive metabolites that may deter the growth of pathogenic microbes. As little is known about the interaction of biofloc systems and the addition of probiotics, this study focused on this integration to manipulate the microbial community and its interactions within biofloc systems. The present study evaluated two probiotics (B. velezensis AP193 and BiOWiSH FeedBuilder Syn 3) for use in Nile tilapia (Oreochromis niloticus) culture in a biofloc system. Nine independent 3785 L circular tanks were stocked with 120 juveniles (71.4 ± 4.4 g). Tilapia were fed for 16 weeks and randomly assigned three diets: a commercial control diet or a commercial diet top-coated with either AP193 or BiOWiSH FeedBuilder Syn3. At 14 weeks, the fish were challenged with a low dose of Streptococcus iniae (ARS-98-60, 7.2 × 107  CFU mL-1 , via intraperitoneal injection) in a common garden experimental design. At 16 weeks, the fish were challenged with a high dose of S. iniae (6.6 × 108  CFU mL-1 ) in the same manner. At the end of each challenge trial, cumulative per cent mortality, lysozyme activity and expression of 4 genes (il-1β, il6, il8 and tnfα) from the spleen were measured. In both challenges, the mortalities of the probiotic-fed groups were significantly lower (p < .05) than in the control diet. Although there were some strong trends, probiotic applications did not result in significant immune gene expression changes related to diet during the pre-trial period and following exposure to S. iniae. Nonetheless, overall il6 expression was lower in fish challenged with a high dose of ARS-98-60, while tnfα expression was lower in fish subjected to a lower pathogen dose. Study findings demonstrate the applicability of probiotics as a dietary supplement for tilapia reared in biofloc systems.

Investigation of dietary exogenous protease and humic substance on growth, disease resistance to Flavobacterium covae and immune responses in juvenile channel catfish (Ictalurus punctatus)

Many bacterial pathogens impact the US catfish industry, and disease control can be challenging for producers. Columnaris disease in channel catfish, Ictalurus punctatus, is primarily caused by Flavobacterium covae (formerly F. columnare). Immunostimulants may enhance nonspecific immune responses and offer an alternative to antibiotic treatments in catfish. Furthermore, dietary protein sources and inclusions are also essential to fish health and nutrition and may enhance overall fish performance in pond culture. The current project evaluated two immunostimulants: a protease complex (PC) and a humic substance (HS) derived from a reed-sedge peat product. A 60-day trial examined the effects of five diets on growth performance, immune response and resistance to experimental F. covae infection in channel catfish. Diets included a high-quality fishmeal diet (32%; CF32), a high-protein soy-based diet (32%; C32), a low-protein soy-based diet (28%; C28; predominately used in industry), a low-protein soy diet supplemented with C28 + PC at 175 g metric ton^-1 and C28 + HS in a low-protein diet at 23 g metric ton^-1 . Following feeding for 60 d, juvenile channel catfish were sampled for growth performance and baseline health indicators (n = 3; body mucus, blood for sera, kidney and spleen). A subset of fish was then subjected to an immersion-based in vivo challenge trial with F. covae (ALG-00-530; 10⁶  CFU mL^-1 exposure). At 60d post-initiation, there were no dietary differences in the relative growth rate (p = .063) or thermal growth coefficient (p = .055), but the 32% diets generally appeared to perform best. Post-challenge, the C32 group's mortality was higher than the C28 + PC (p = .006) and C28 + HS diets (p = .005). Although not significant, the C28 and CF32 groups also demonstrated higher mortality compared to both PC and HS diets. Sera lysozyme concentration was found to increase following pathogen challenge (p < .001) and in comparison with mock-challenged catfish (p < .001). Elevated expression levels of proinflammatory cytokines (il-1β, il-8, tnf-α and tgf-β) were observed at trial midpoint and post-infection when compared to 60d. The C28 treatment was found to have lower tnf-α expression than the C28 + PC (p = .042) and C28 + HS (p = .042) groups following exposure to F. covae. These challenge data suggest that the immunostimulants (PC and HS) in plant-based protein may be beneficial in protecting against F. covae when offered in low-protein channel catfish diets.

Transcriptomic profiles of Florida pompano (Trachinotus carolinus) gill following infection by the ectoparasite Amyloodiniumocellatum

The dinoflagellate Amyloodinium ocellatum is an important pathogenic parasite infecting cultured marine and brackish water fishes worldwide. This includes cultured Florida pompano (Trachinotus carolinus), which is one of the most desirable marine food fish with high economic value in the USA. A. ocellatum infects fish gills and causes tissue damage, increased respiratory rate, reduced appetite, and mortality, especially in closed aquaculture systems. This study mimicked the natural infection of A. ocellatum in cultured pompano and conducted a transcriptomic comparison of gene expression in the gills of control and A. ocellatum infected fish to explore the molecular mechanisms of infection. RNA-seq data revealed 604 differentially expressed genes in the infected fish gills. The immunoglobulin genes (including IgM/T) augmentation and IL1 inflammation suppression were detected after infection. Genes involved in reactive oxygen species mediating parasite killing were also highly induced. However, excessive oxidants have been linked to oxidative tissue damage and apoptosis. Correspondingly, widespread down-regulation of collagen genes and growth factor deprivation indicated impaired tissue repair, and meanwhile the key executor of apoptosis, caspase-3 was highly expressed (25.02-fold) in infected fish. The infection also influenced the respiratory gas sensing and transport genes and established hypoxic conditions in the gill tissue. Additionally, food intake and lipid metabolism were also affected. Our work provides the transcriptome sequencing of Florida pompano and provides key insights into the acute pathogenesis of A. ocellatum. This information can be utilized for designing optimal disease surveillance strategies, future selection for host resistance, and development of novel therapeutic measures.

Sources of variation in elemental profiles of whiteleg shrimp (Litopenaeus vannamei) and their potential effects on the accuracy of discriminant analysis

BACKGROUND

Elemental profiling is a tool that has been proposed to improve the traceability of seafood products. Small sources of variation can affect the outcome of elemental profiling and therefore pose to lower the overall accuracy of analyses. Here, we investigate two potential sources of variation through three experiments: laboratory variation (intra-, interlaboratory variation, and tissue matrix) and tissue variation.

METHODS AND RESULTS

Samples of whitleleg shrimp (Litopenaeus vannamei) were obtained from 20 farms in Ecuador and two farms in Alabama to be analyzed. In the first experiment of the study, samples from Ecuador were analyzed at three different laboratories and compared. Two out of the five elements reported were statistically different across the three laboratories (Cu and Se). In the second experiment, the effect of tissue matrix (ground vs whole tissue during acid digestion) was investigated. Altogether, five out of 29 elements analyzed were statistically different. In the third experiment, samples from two farms in Alabama were analyzed to understand the variation in element concentrations in different tissues (head on shell on (HOSO), headless shell on (HLSO), headless peeled (PLD) and headless peeled and deveined (PLDV)). Elemental concentrations varied across tissues, and patterns in elemental concentrations were site specific. The samples from the two farms were analyzed with a Random Forest classification model to site x tissue groupings with 94% accuracy.

CONCLUSION

The result of this study highlights the following: 1. Consistency in laboratory analysis important in studies that involve element concentrations, as minor differences in methodology can propagate as significant differences in results. 2. In shrimp, elements are compartmentalized in different tissues and elemental profiling should consistently use the same type of tissue.

Growth, serum biochemical parameters, salinity tolerance and antioxidant enzyme activity of rainbow trout (Oncorhynchus mykiss) in response to dietary taurine levels

This study evaluated the effect of dietary taurine levels on growth, serum biochemical parameters, salinity adaptability, and antioxidant activity of rainbow trout (Oncorhynchus mykiss). Four diets were formulated with taurine supplements at 0, 0.5, 1, and 2% w/v (abbreviated as T₀, T_0.5, T₁, and T₂, respectively). Rainbow trouts (initial weight of 80.09 ± 4.72 g) were stocked in tanks (180 L capacity), and were fed these diets for six weeks and subsequently underwent salinity acclimation. Physiological indicators were determined before salinity acclimation at 1, 4, 7, and 14 days afterwards. Results showed that there were no significant differences in growth performance (final mean weight ranged from 182.35 g to 198.48 g; percent weight gain was between 127.68% and 147.92%) of rainbow trout in freshwater stage, but dietary taurine supplement significantly increased serum-free taurine content. After entering seawater, the Na⁺-K⁺-ATPase activity of T₂ group returned to its freshwater levels, and the serum cortisol content was significantly higher than T₀ and T_0.5 groups. At the end of this experiment, the liver superoxide dismutase activity in the T₀ and T_0.5 groups was significantly lower than in the T₁ and T₂ groups, and the liver catalase in the T₀ group was the lowest whereas that in the T₂ group was the highest. Muscle malondialdehyde content was the highest in the T₀ group, and the lowest in the T₂ group. Based on the results of this study, supplement of dietary taurine (0.5-2%) enhanced the salinity tolerance in rainbow trout, which increased with the higher taurine concentration.

A preliminary survey of antibiotic residues in frozen shrimp from retail stores in the United States

Shrimp are an important and valuable commodity for aquaculture that are widely traded internationally. Widespread antibiotic use has been documented in shrimp farming and is a common source of criticism of aquaculture products. Additionally, previous reports have found some evidence of antibiotic residues in shrimp samples obtained from retail stores in the United States, which is a concern for consumers. To further understand the prevalence of antibiotics in retail shrimp in the United States, shrimp samples obtained from grocery stores across 16 states were analyzed for 74 antibiotic compounds/metabolites at a commercial laboratory. 68 samples were analyzed for a multiclass antibiotic panel which included 66 antibiotics while a subset of 15 samples were analyzed for β-lactam antibiotics, Nitrofurans, and Oxytetracycline. Samples were obtained that were labeled as being from major production countries, including India, Indonesia, Thailand, and Vietnam. No detectable antibiotic residues were found in this survey in any samples. This is contrary to previous findings in frozen shrimp analyzed for antibiotics, which typically report low levels of the prevalence of antibiotics.

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Shrimp were collected from grocery stores in various locations in the US.

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68 samples were tested for a panel of 66 antibiotics.

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15 samples were tested for β-lactam, nitrofuran, and tetracycline residues.

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Testing showed no positive results for antibiotic residues.

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Larger surveys are needed to determine the presence of antibiotics in shrimp products.

Trace element concentrations in white leg shrimp Litopenaeus vannamei from retail stores in the EU, UK, and USA and the ability to discern country of origin with classification models

Shrimp are a globally traded aquaculture commodity that accounts for a large proportion of the monetary value of aquaculture. There are concerns among consumers about seafood labeling fraud and environmental sustainability. Therefore, the geographic origin of shrimp from retail stores was investigated with trace element profiling. 94 shrimp samples were collected from grocery stores across the USA, UK, and EU in 70 different grocery stores. The results of 24 elements are reported. Shrimp samples were from Thailand, India, Vietnam, Indonesia, and Ecuador were shown to have 15 elements that were statistically different across labeled country of origin, with Ecuador having unique post hoc group membership in 5 of the elements. Based on a classification procedure, shrimp were classified to labeled country of origin with an overall accuracy of 71.2%. Overall, the results suggest that elemental profiling could be a traceability tool for classifying samples of shrimp from retail stores.

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Frozen Shrimp samples were obtained from grocery stores in the EU and USA.

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Samples were analyzed for element concentrations in 42 elements.

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24 elements were detectable and presented here.

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Samples from Ecuador shown property of having a unique elemental profile.

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Samples were classified to country of origin with reasonable accuracy (71%).

Effect of salinity on growth, survival, and serum osmolality of red snapper, Lutjanus campechanus

Three trials were conducted to evaluate the performances of red snapper, Lutjanus campechanus, in low salinities. The median lethal concentration (96 h LC50) of salinity was determined by trimmed Spearman-Karber method using survival data of fish (18.9 ± 0.2 g) collected after 96 h from acclimation to 2, 4, 8, and 32 ppt salinities in 800 L tanks (n = 3), while the serum osmolality of fish (74.1 ± 3.9 g) was determined after 48 h from acclimation to 6, 8, 16, 24, and 32 ppt salinities in 150 L tanks (n = 3). The growth trial was conducted for 6 weeks in 800 L tanks to determine the growth and survival of fish (18.8 ± 0.2 g) at 8 ppt salinity compared to the control (32 ppt salinity). At the conclusion, the isosmotic point of fish was estimated as 357.2 mmol/kg (correspond to 11.0 ppt salinity), while the 96 h LC50 was estimated as 5.65 ppt salinity. No significant differences were noted for survival and FCR of fish reared in 8 and 32 ppt salinities. However, growth was significantly lower in fish reared in 8 ppt salinity compared to the fish reared in 32 ppt salinity. The reduced growth could be, at least partially, due to the increased osmoregulatory energy expenditure at lower salinities.

Replacement of fish meal with Bacillus pumillus SE5 and Pseudozyma aphidis ZR1 fermented soybean meal in diets for Japanese seabass (Lateolabrax japonicus)

This study examined the effects of replacing fish meal (FM) with three different types of soybean meal (SM) including untreated SM, Bacillus pumillus SE5 (BP) fermented SM (BPFSM) and Pseudozyma aphidis ZR1 (PA) fermented SM (PAFSM) in diets for Japanese seabass (Lateolabrax japonicus). A basal diet was formulated using FM (FM diet), and six other diets were produced by substituting 40 or 80% of FM with SM, BPFSM or PAFSM (SM40, SM80, BPFSM40, BPFSM80, PAFSM40 and PAFSM80 diets). Each diet was fed to triplicate groups of fish (7.14 ± 0.05 g) twice daily for eight weeks. Replacing 40% of FM with SM sources did not significantly influence growth (P > 0.05), while increasing the substitution level to 80% led to reduced growth rates (P < 0.05). The groups received SM80 and PAFSM80 diets showed significantly higher feed conversion ratio and lower protein digestibility than FM group. Furthermore, notably lower dry matter digestibility was detected in SM80 group. Remarkably lower serum total antioxidant capacity was found in the SM80 group, and catalase activity did not significantly differ between FM and BPFSM40 groups. Serum malondialdehyde concentration was enhanced by increasing FM replacement level and the highest value was observed in the SM80 fed fish. FM and PAFSM40 groups showed significantly higher lysozyme activity than the SM80 group. Fish fed the BPFSM40 diet exhibited the highest complement C3 activity and the lowest value was observed in the SM80 group. Expression of lysozyme gene in spleen was down-regulated in the SM80 group, and no significant difference in expression of C3 gene was found among FM, BPFSM40 and PAFSM40 groups. Digestive enzymes activity and gut morphology were significantly influenced by FM replacement. Expression of HSP70 and pro-inflammatory genes including TNF-α and IL-1β were up-regulated by FM replacement and relatively lower expression levels were found by using fermented SM. An opposite trend was observed for the anti-inflammatory TGF-β gene expression. Serum d-lactate concentration was significantly increased by replacing 80% of FM with any of the SM sources. These findings indicated that using fermented SM, particularly BPFSM, beneficially influences feed utilization, antioxidant capacity, innate immunity and gut health in juvenile Japanese seabass.

PAX2 function, regulation and targeting in fallopian tube-derived high-grade serous ovarian cancer

The fallopian tube epithelium (FTE) is one of the progenitor populations for high-grade serous ovarian cancer (HGSC). Loss of PAX2 is the earliest known molecular aberration in the FTE occurring in serous carcinogenesis followed by a mutation in p53. Pathological studies report consistent loss of PAX2 in benign lesions as well as serous tumors. In the current study, the combined loss of PAX2 and expression of the R273H p53 mutant protein in murine oviductal epithelial (MOE) cells enhanced proliferation and growth in soft agar in vitro but was insufficient to drive tumorigenesis in vivo. A serially passaged model was generated to investigate the role of aging, but was also insufficient to drive tumorigenesis. These models recapitulate early benign lesions and suggest that a latency period exists between loss of PAX2, p53 mutation and tumor formation. Stathmin and fut8 were identified as downstream targets regulated by loss of PAX2 and mutation of p53 in MOE cells. Re-expression of PAX2 in PAX2-null human HGSC cells reduced cell survival via apoptosis. Phosphatase and tensin homolog (PTEN)^shRNA negatively regulated PAX2 expression and stable re-expression of PAX2 in MOE:PTEN^shRNA cells significantly reduced proliferation and peritoneal tumor formation in athymic nude mice. PAX2 was determined to be a direct transcriptional target that was activated by wild-type p53, whereas mutant p53 inhibited PAX2 transcription in MOE cells. A small molecule screen using the proximal PAX2 promoter driving luciferase identified four small molecules that were able to enhance PAX2 mRNA expression in MOE cells. PAX2 re-expression in HGSC cells and PTEN-deficient oviductal tumors may have the potential to induce apoptosis. In summary, mutant p53 and PTEN loss negatively regulated PAX2 and PAX2 re-expression in HGSC cells induced cell death.

Impact of feed additives on surface mucosal health and columnaris susceptibility in channel catfish fingerlings, Ictalurus punctatus

One of the highest priority areas for improvement in aquaculture is the development of dietary additives and formulations which provide for complete mucosal health and protection of fish raised in intensive systems. Far greater attention has been paid to dietary impact on gut health than to protective effects at other mucosal surfaces such as skin and gill. These exterior surfaces, however, are important primary targets for pathogen attachment and invasion. Flavobacterium columnare, the causative agent of columnaris disease, is among the most prevalent of all freshwater disease-causing bacteria, impacting global aquaculture of catfish, salmonids, baitfish and aquaria-trade species among others. This study evaluated whether the feeding of a standard catfish diet supplemented with Alltech dietary additives Actigen(®), a concentrated source of yeast cell wall-derived material and/or Allzyme(®) SSF, a fermented strain of Aspergillus niger, could offer protection against F. columnare mortality. A nine-week feeding trial of channel catfish fingerlings with basal diet (B), B + Allzyme(®) SSF, B + Actigen(®) and B + Actigen(®)+Allzyme(®) SSF revealed good growth in all conditions (FCR < 1.0), but no statistical differences in growth between the treatments were found. At nine weeks, based on pre-challenge trial results, basal, B + Actigen(®), and B + Allzyme(®) SSF groups of fish were selected for further challenges with F. columnare. Replicated challenge with a virulent F. columnare strain, revealed significantly longer median days to death in B + Allzyme(®) SSF and B + Actigen(®) when compared with the basal diet (P < 0.05) and significantly higher survival following the eight day challenge period in B + Actigen(®) when compared with the other two diets (P < 0.05). Given the superior protection provided by the B + Actigen(®) diet, we carried out transcriptomic comparison of gene expression of fish fed that diet and the basal diet before and after columnaris challenge using high-throughput RNA-seq. Pathway and enrichment analyses revealed changes in mannose receptor DEC205 and IL4 signaling at 0 h (prior to challenge) which likely explain a dramatic divergence in expression profiles between the two diets soon after pathogen challenge (8 h). Dietary mannose priming resulted in reduced expression of inflammatory cytokines, shifting response patterns instead to favor resolution and repair. Our results indicate that prebiotic dietary additives may provide protection extending beyond the gut to surface mucosa.

Cultural considerations in the treatment of persons with AIDS

The impact of AIDS has been most notable in three subpopulations in the United States: the gay community, intravenous drug abusers and minority groups, particularly Blacks and Hispanics. Little information is available on the cultural considerations which are relevant in the treatment of these individuals. This article describes basic principles of cross-cultural analysis, explores individual aspects of AIDS in these populations and discusses the implications for health care providers.

Changes in free amino acid profile of red snapper Lutjanus campechanus, eggs, and developing larvae

The free amino acids (FAA) profile was determined for newly fertilized eggs and resultant larvae from wild-caught red snapper Lutjanus campechanus induced to spawn with hCG. Yolk sac and oil globule volumes of eggs and larvae were monitored over time from digital photographs. FAA profiles of the eggs and larvae were measured in picomoles (pmol) of FAA/mg of eggs by HPLC. Newly fertilized eggs had a mean total FAA content of 21.72 +/- 3.55 nmoles/egg (92.81 +/- 9.71 nmoles/mg eggs). Leucine, valine, lysine, and isoleucine were the most abundant essential FAA comprising 35.9% of the total FAA. Alanine, serine, asparagine, and glycine were the most abundant non-essential FAA comprising 34.2% of the total FAA. At 24 h post-hatch (hph) the mean total FAA had decreased by 81% since egg fertilization. The bulk of the FAA decrease was between the time of hatch and 12 hph. Only 8.5 +/- 1.5% of the initial concentration in fertilized eggs of isoleucine, 9.7 +/- 2.5% of arginine, and 9.9 +/- 2.0% of threonine remained at 12 hph. Among the non-essential FAA, alanine dropped the most by 12 hph with 4.6% of the concentration found in a recently fertilized egg remaining, while cysteine had increased 254.7 +/- 26.2%. The yolk sac volume decreased rapidly in the first 12 hph and was further reduced 77.0 +/- 2.5% from 12 to 24 hph. The oil globule depletion rate was a more linear decline from fertilized egg to 36 hph.

Educational outreach visits: effects on professional practice and health care outcomes

BACKGROUND

Educational outreach visits (EOVs) have been identified as an intervention that may improve the practice of healthcare professionals. This type of face-to-face visit has been referred to as university-based educational detailing, academic detailing, and educational visiting.

OBJECTIVES

To assess the effects of EOVs on health professional practice or patient outcomes.

SEARCH STRATEGY

For this update, we searched the Cochrane EPOC register to March 2007. In the original review, we searched multiple bibliographic databases including MEDLINE and CINAHL.

SELECTION CRITERIA

Randomised trials of EOVs that reported an objective measure of professional performance or healthcare outcomes. An EOV was defined as a personal visit by a trained person to healthcare professionals in their own settings.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality. We used bubble plots and box plots to visually inspect the data. We conducted both quantitative and qualitative analyses. We used meta-regression to examine potential sources of heterogeneity determined a priori. We hypothesised eight factors to explain variation across effect estimates. In our primary visual and statistical analyses, we included only studies with dichotomous outcomes, with baseline data and with low or moderate risk of bias, in which the intervention included an EOV and was compared to no intervention.

MAIN RESULTS

We included 69 studies involving more than 15,000 health professionals. Twenty-eight studies (34 comparisons) contributed to the calculation of the median and interquartile range for the main comparison. The median adjusted risk difference (RD) in compliance with desired practice was 5.6% (interquartile range 3.0% to 9.0%). The adjusted RDs were highly consistent for prescribing (median 4.8%, interquartile range 3.0% to 6.5% for 17 comparisons), but varied for other types of professional performance (median 6.0%, interquartile range 3.6% to 16.0% for 17 comparisons). Meta-regression was limited by the large number of potential explanatory factors (eight) with only 31 comparisons, and did not provide any compelling explanations for the observed variation in adjusted RDs. There were 18 comparisons with continuous outcomes, with a median adjusted relative improvement of 21% (interquartile range 11% to 41%). There were eight trials (12 comparisons) in which the intervention included an EOV and was compared to another type of intervention, usually audit and feedback. Interventions that included EOVs appeared to be slightly superior to audit and feedback. Only six studies evaluated different types of visits in head-to-head comparisons. When individual visits were compared to group visits (three trials), the results were mixed.

AUTHORS' CONCLUSIONS

EOVs alone or when combined with other interventions have effects on prescribing that are relatively consistent and small, but potentially important. Their effects on other types of professional performance vary from small to modest improvements, and it is not possible from this review to explain that variation.

Branchial carbonic anhydrase activity and ninhydrin positive substances in the Pacific white shrimp, Litopenaeus vannamei, acclimated to low and high salinities

The Pacific white shrimp, Litopenaeus vannamei, acclimated to 30 ppt salinity, was transferred to either low (15 and 5 ppt), or high (45 ppt) salinity for 7 days. Hemolymph osmolality, branchial carbonic anhydrase activity, and total ninhydrin-positive substances (TNPS) in abdominal muscle were then measured for each condition. Hemolymph osmotic concentration was regulated slightly below ambient water osmolality in shrimp acclimated to 30 ppt. At 15 and 5 ppt, shrimp were strong hyper-osmotic regulators, maintaining hemolymph osmolality between 200 and 400 mOsm above ambient. Shrimp acclimated to 30 ppt and transferred to 45 ppt salinity were strong hypo-osmotic and hypo-ionic regulators, maintaining hemolymph osmolality over 400 mOsm below ambient. Branchial carbonic anhydrase (CA) activity was low (approximately 100 micromol CO(2) mg protein(-1) min(-1)) and uniform across all 8 gills in shrimp acclimated to 30 ppt, but CA activity increased in all gills after exposure to both low and high salinities. Anterior gills had the largest increases in CA activity, and levels of increase were approximately the same for low and high salinity exposure. Branchial CA induction appears to be functionally important in both hyper- and hypo-osmotic regulations of hemolymph osmotic concentrations. Abdominal muscle TNPS made up between 19 and 38% of the total intracellular osmotic concentration in shrimp acclimated to 5, 15, and 30 ppt. TNPS levels did not change across this salinity range, over which hemolymph osmotic concentrations were tightly regulated. At 45 ppt, hemolymph osmolality increased, and muscle TNPS also increased, presumably to counteract intracellular water loss and restore cell volume. L. vannamei appears to employ mechanisms of both extracellular osmoregulation and intracellular volume regulation as the basis of its euryhalinity.

Acute and 1-month effect of small-volume suction lipectomy on insulin sensitivity and cardiovascular risk

OBJECTIVE

The most common surgical procedure for obesity is liposuction, the majority of which are small-volume procedures. The effect of large-volume liposuction on cardiovascular risk and insulin sensitivity has been variable. This study was performed to evaluate the effect of the more common, smaller-volume liposuction on insulin sensitivity, inflammatory mediators, and cardiovascular risk factors.

SUBJECTS AND STUDY DESIGN

In all, 15 overweight or obese premenopausal women underwent metabolic evaluation prior to, 1 day following and 1 month following suction lipectomy of the abdomen. Metabolic evaluation included assessment of free fatty acids, glucose, insulin, insulin sensitivity by frequently sampled i.v. glucose tolerance test, and adipokines (IL-6, angiotensin II, leptin, PAI-1, adiponectin, and TNF-alpha).

RESULTS

Free fatty acids did not change acutely although there was an almost 30% decrease in free fatty acids at 1 month. Fasting insulin levels decreased at one month from 8.3 +/- 1.1 to 5.6 +/- 1.3 microU/ml (P = 0.006). Insulin sensitivity by i.v. glucose tolerance test did not change at 1 month (4.0 +/- 0.8 to 5.0 +/- 0.7, P = 0.12) although with subgroup analysis insulin sensitivity improved in obese but not overweight participants. Several adipokines worsened acutely (IL-6 increased 15 fold and angiotensin II increased 67%), but there was no change in PAI-1, and other adipokines (adiponectin, leptin, and TNF-alpha) decreased. At the 1-month follow-up, all adipokines were similar to baseline.

CONCLUSION

This study provides little evidence supporting increased or decreased cardiovascular risk although there is evidence supporting improved insulin sensitivity at one month, especially in obese women.

Hypoxia induces lytic replication of Kaposi sarcoma-associated herpesvirus

There is substantial evidence that Kaposi sarcoma-associated herpesvirus (KSHV) plays an important role in the pathogenesis of all forms of Kaposi sarcoma (KS). It has been noted that KS commonly occurs in locations, such as the feet, where tissue may be poorly oxygenated. On the basis of this observation, the potential role of hypoxia in the reactivation of KSHV replication was explored by studying 2 KSHV-infected primary effusion lymphoma B-cell lines (BC-3 and BCBL-1) latently infected with KSHV. Acute and chronic exposure of these cells to hypoxia (1% O(2)) induced KSHV lytic replication, as indicated by an increase in intracellular lytic protein expression and detection of virus in cell supernatants by Western immunoblotting. In addition, hypoxia increased the levels of secreted viral interleukin-6. Moreover, hypoxia enhanced the lytic replication initiated by the viral inducer 12-O-tetradecanoylphorbol-13-acetate. Desferoxamine and cobalt chloride, 2 compounds that increase the intracellular levels of hypoxia-inducible factor 1, were also able to induce KSHV lytic replication. These studies suggest that hypoxia is an inducer of KSHV replication. This process may play an important role in the pathogenesis of KS.

Targeted inhibition of calcineurin signaling blocks calcium-dependent reactivation of Kaposi sarcoma-associated herpesvirus

Kaposi sarcoma-associated herpesvirus (KSHV) is associated with KS, primary effusion lymphoma (PEL), and multicentric Castleman disease. Reactivation of KSHV in latently infected cells and subsequent plasma viremia occur before the development of KS. Intracellular signaling pathways involved in KSHV reactivation were studied. In latently infected PEL cells (BCBL-1), KSHV reactivation in single cells was determined by quantitative flow cytometry. Viral particle production was determined by electron microscope analyses and detection of minor capsid protein in culture supernatants. Agents that mobilized intracellular calcium (ionomycin, thapsigargin) induced expression of KSHV lytic cycle-associated proteins and led to increased virus production. Calcium-mediated virus reactivation was blocked by specific inhibitors of calcineurin-dependent signal transduction (cyclosporine, FK506). Similarly, calcium-mediated virus reactivation in KSHV-infected dermal microvascular endothelial cells was blocked by cyclosporine. Furthermore, retroviral transduction with plasmid DNA encoding VIVIT, a peptide specifically blocking calcineurin-NFAT interactions, inhibited calcium-dependent KSHV reactivation. By contrast, chemical induction of lytic-phase infection by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate was blocked by protein kinase C inhibitors, but not by calcineurin inhibitors. In summary, calcineurin-dependent signal transduction, an important signaling cascade in vivo, induces calcium-dependent KSHV replication, providing a possible target for the design of antiherpesvirus strategies in KSHV-infected patients.

Is there a role for extracorporeal life support after stage I Norwood?

OBJECTIVES

Controversy still surrounds the use of extracorporeal life support (ECLS) in patients with single ventricle physiology. An analysis of the experience with a group of neonates who underwent stage I Norwood palliation and received ECLS is reported.

METHODS

A retrospective review of hospital records, operative notes and perfusion data was performed in a group of 12 consecutive patients undergoing ECLS in the perioperative period after stage I. An analysis to identify risk factors for poor outcome was performed.

RESULTS

The mean age and weight were 3.9 days (1-14) and 2.6 kg (1.4-3.8), respectively. There were 3/12 patients under 2.5 kg and four patients were under 35 weeks of gestation. The most common diagnosis (7/12) was hypoplastic left heart syndrome with aortic atresia. Associated extracardiac anomalies were present in four patients. Three patients had an additional cardiac defect and two of these required an additional surgical procedure besides the stage I Norwood. The mean circulatory arrest was 56 min (46-63). ECLS was initiated preoperatively in one, intraoperatively in nine, and postoperatively in two patients. The indication for support was: arrhythmia (one), low output (six), cardiac arrest (three), unbalanced circulation (one), and hypoxemia (two). The mean duration of support was 68 h (24-192). Eight patients were weaned off support, and six were discharged home in good condition. Morbidity included sepsis in five, renal failure in five, neurologic sequelae in three, and bleeding in two. Prematurity, renal dysfunction and the initiation of ECLS outside the operating room were significantly associated with poor outcome. Residual hemodynamic effect, low birth weight and neurologic event showed a tendency towards poor outcome, but did not reach statistical significance.

CONCLUSIONS

Although the use of ECLS in patients with single ventricle physiology still carries a significant risk, prompt initiation of support can improve the outcome in a group of patients with impaired cardiopulmonary function after stage I palliation.

Getting evidence into practice: the work of the Cochrane Effective Practice and Organization of care Group (EPOC)

Policy makers and continuing educators often face difficult decisions about which educational and quality assurance interventions to provide. Where possible, such decisions are best informed by rigorous evidence, such as that provided by systematic reviews. The Cochrane Collaboration is an international organization that aims to help people make well-informed decisions about health care by preparing, maintaining, and ensuring the accessibility of systematic reviews of the benefits and risks of health care interventions. International collaborative review groups prepare Cochrane reviews for publication in The Cochrane Library, a collection of databases available on CD-ROM and the World Wide Web and updated quarterly. The Cochrane Effective Practice and Organization of Care Group (EPOC) aims to prepare and maintain systematic reviews of professional, financial, organizational, and regulatory interventions that are designed to improve professional practice and the delivery of effective health services. EPOC has 17 reviews and 20 protocols published in Issue 3, 2000, of the Cochrane Library, with further protocols in development. We also have undertaken an overview of previously published systematic reviews of professional behavior change strategies. Our specialized register contains details of over 1,800 studies that fall within the group's scope. Systematic reviews provide a valuable source of information for policy makers and educators involved in planning continuing education and quality assurance initiatives and organizational change. EPOC will attempt to keep the Journal of Continuing Education in the Health Professions informed on an ongoing basis about new systematic reviews that it produces in the area of continuing medical education and quality assurance.

Continuing education meetings and workshops: effects on professional practice and health care outcomes

BACKGROUND

Educational meetings and printed educational materials are the two most common types of continuing education for health professionals. An important aim of continuing education is to improve professional practice so that patients can receive improved health care.

OBJECTIVES

To assess the effects of educational meetings on professional practice and health care outcomes.

SEARCH STRATEGY

We searched the Cochrane Effective Practice and Organisation of Care Group specialised register, MEDLINE (from 1966), the Research and Development Resource Base in Continuing Medical Education in January 1999 and reference lists of articles.

SELECTION CRITERIA

Randomised trials or well designed quasi-experimental studies examining the effect of continuing education meetings (including lectures, workshops, and courses) on the clinical practice of health professionals or health care outcomes.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied inclusion criteria, assessed the quality of each study, and extracted study data. We attempted to collect missing data from investigators. We conducted both qualitative and quantitative analyses.

MAIN RESULTS

Thirty-two studies were included with a total of 36 comparisons. The studies involved from 13 to 411 health professionals (total N= 2995) and were judged to be of moderate or high quality, although methods were generally poorly reported. There was substantial variation in the complexity of the targeted behaviours, baseline compliance, the characteristics of the interventions and the results. The heterogeneity of the results was best explained by differences in the interventions. For 10 comparisons of interactive workshops, there were moderate or moderately large effects in six (all of which were statistically significant) and small effects in four (one of which was statistically significant). For interventions that combined workshops and didactic presentations, there were moderate or moderately large effects in 12 comparisons (eleven of which were statistically significant) and small effects in seven comparisons (one of which was statistically significant). In seven comparisons of didactic presentations, there were no statistically significant effects, with the exception of one out of four outcome measures in one study.

REVIEWER'S CONCLUSIONS

Interactive workshops can result in moderately large changes in professional practice. Didactic sessions alone are unlikely to change professional practice.

Longitudinal compensation for fat-induced insulin resistance includes reduced insulin clearance and enhanced beta-cell response

Central adiposity is highly correlated with insulin resistance, which is an important risk factor for type 2 diabetes and other chronic diseases. However, in normal individuals, central adiposity can be tolerated for many years without development of impaired glucose tolerance or diabetes. Here we examine longitudinally the mechanisms by which glucose tolerance can be maintained in the face of substantial insulin resistance. Normal dogs were fed a diet enriched with moderate amounts of fat (2 g x kg(-1) x day(-1)), similar to that seen in modern "cafeteria" diets, and the time course of metabolic changes in these animals was examined over 12 weeks. Trunk adiposity as assessed by magnetic resonance imaging increased from 12 to 19%, but body weight remained unchanged. Insulin sensitivity (SI) as determined by frequently sampled intravenous glucose tolerance tests was measured over a 12-week period. SI decreased 35% by week 1 and remained impaired for the entire 12 weeks. Intravenous glucose tolerance was reduced transiently for 1 week, recovered to baseline, and then again began to decline after 8 weeks. First-phase insulin response began to increase after week 2, peaked by week 6 (190% of basal), and then declined. The increase in insulin response was due partially to enhanced beta-cell function (22%) but due also to an approximately 50% reduction in insulin clearance. This compensation by insulin clearance was also confirmed with insulin clamps performed in fat-fed versus control dogs. The present study confirms the ability of the normal individual to compensate for fat-induced insulin resistance by enhanced insulin response, such that the product of insulin sensitivity x secretion is little changed. However, the compensation is due as much to reduced insulin clearance as increased beta-cell sensitivity to glucose. Reduced hepatic extraction of insulin may be the first line of defense providing a higher proportion of secreted insulin to the periphery and sparing the beta-cells during compensation for the insulin-resistant state.

Continuing medical education: a new vision of the professional development of physicians

The authors describe their vision of what continuing medical education (CME) should become in the changing health care environment. They first discuss six types of literature (e.g., concerning learning and adult development principles, problem-based/practice-based learning, and other topics) that contribute to ways of thinking about and understanding CME. They then state their view that the Association of American Medical Colleges (AAMC) has made a commitment to helping CME be more effective in the professional development of physicians. In presenting their new vision of CME, the authors describe their interpretation of the nature and values of CME (e.g., optimal CME is highly self-directed; the selection and design of the most relevant CME is based on data from each physician's responsibilities and performance; etc.). They then present seven action steps, suggestions to begin them, and the institutions and organizations they believe should carry them out, and recommend that the AAMC play a major role in supporting activities to carry out these steps. (For example, one action step is the generation and application of new knowledge about how and why physicians learn, select best practices, and change their behaviors). Six core competencies for CME educators are defined. The authors conclude by stating that collaboration among the appropriate academic groups, professional associations, and health care institutions, with leadership from the AAMC, is essential to create the best learning systems for the professional development of physicians.

Autosomal dominantly inherited generalized basaloid follicular hamartoma syndrome: report of a new disease in a North Carolina family

BACKGROUND

An 8-year-old girl presented with hundreds of milia, measuring 1 to 2 mm; comedone-like lesions; skin-colored and hyperpigmented papules on the face, scalp, ears, neck, upper trunk, and lower arms along with diffuse scalp hypotrichosis; and pinpoint palm/sole pits. Onset was in early childhood and the disease was historically present in 6 generations.

OBJECTIVE

Our objectives were to delineate the clinical and histopathologic features and mode of inheritance as a base for gene studies.

METHODS

Eighteen family subjects were studied. Twenty-six skin biopsy specimens were examined. A detailed pedigree was constructed. A complete literature search was done concerning diseases with generalized basaloid follicular hamartomas.

RESULTS

The lesions were basaloid follicular hamartomas and other folliculocentric abnormalities. Inheritance was autosomal dominant. Extensive literature search confirmed the finding of a unique genodermatosis.

CONCLUSION

A new genodermatosis termed dominantly inherited generalized basaloid follicular hamartoma syndrome was defined by delineating its clinical and histopathologic features and mode of inheritance and by extensive literature review.

Lymphangioma-like Kaposi's sarcoma: etiology and literature review

Much confusion surrounds a rare and occasionally described variant of Kaposi's sarcoma (KS) known as lymphangioma-like or bullous KS. We describe the typical clinical and histologic features and elucidate the etiologic cell in lymphangioma-like KS. A computer-based review of the English-language literature was performed. Routine histologic and immunoperoxidase techniques were performed on formalin-fixed tissue. Immunoperoxidase staining for anti-CD31, anti-CD34, and anti-factor VIII-related antigen suggests that the etiologic cell of origin is the vascular endothelial cell. Lymphangioma-like KS has been described for more than a century and given various names. Dilated vascular spaces correlate with the clinically bullous lesions, which are veritable KS and not a secondary reaction to it.

HIV-2 protease is inactivated after oxidation at the dimer interface and activity can be partly restored with methionine sulphoxide reductase

Human immunodeficiency viruses encode a homodimeric protease that is essential for the production of infectious virus. Previous studies have shown that HIV-1 protease is susceptible to oxidative inactivation at the dimer interface at Cys-95, a process that can be reversed both chemically and enzymically. Here we demonstrate a related yet distinct mechanism of reversible inactivation of the HIV-2 protease. Exposure of the HIV-2 protease to H(2)O(2) resulted in conversion of the two methionine residues (Met-76 and Met-95) to methionine sulphoxide as determined by amino acid analysis and mass spectrometry. This oxidation completely inactivated protease activity. However, the activity could be restored (up to 40%) after exposure of the oxidized protease to methionine sulphoxide reductase. This treatment resulted in the reduction of methionine sulphoxide 95 but not methionine sulphoxide 76 to methionine, as determined by peptide mapping/mass spectrometry. We also found that exposure of immature HIV-2 particles to H(2)O(2) led to the inhibition of polyprotein processing in maturing virus particles comparable to that demonstrated for HIV-1 particles. Thus oxidative inactivation of the HIV protease in vitro and in maturing viral particles is not restricted to the type 1 proteases. These studies indicate that two distinct retroviral proteases are susceptible to inactivation after a very minor modification at residue 95 of the dimer interface and suggest that the dimer interface might be a viable target for the development of novel protease inhibitors.

Detection of clinically silent intracranial emboli ipsilateral to internal carotid occlusions during cerebral angiography

OBJECTIVE

Embolic ischemic events have long been suspected to occur in the cerebral arteries distal to an ipsilateral occluded internal carotid artery (ICA). Documentation of microemboli by transcranial Doppler sonography during catheter angiography in patients with ICA occlusions provides objective evidence of such distal emboli.

SUBJECTS AND METHODS

Seven patients undergoing carotid angiography were evaluated with transcranial Doppler sonography. Patients were also screened for ICA occlusions using carotid duplex sonography. In the seven patients, we saw five right ICA occlusions and two left ICA occlusions. Real-time visual and auditory confirmations of emboli were obtained by recognizing their specific spectral signatures and harmonic qualities. Routes of collateral flow were determined from angiography. Specific phases of the examination were correlated with embolic occurrences.

RESULTS

Overall, emboli were seen during all phases of arteriography. In the individual patients, emboli were identified in one to four of the eight angiographic phases we defined. Most emboli occurred during catheter flushing and contrast injection rather than during wire and catheter manipulation. The emboli were detected in the middle cerebral artery distribution ipsilateral to the occluded ICA in all seven patients. Collateral flow patterns included, in four patients, external carotid artery-to-ICA collateral flow; in all seven patients, patent anterior communicating arteries; and in three patients, patent posterior communicating arteries.

CONCLUSION

Emboli seen in middle cerebral arteries ipsilateral to occluded ICAs during cerebral angiography strongly indicate that emboli can occur distal to an occlusion. Our findings support the thought that emboli arising from sources proximal to an occluded ICA may reach the hemisphere distal to the occlusion, resulting in parenchymal ischemia or infarction.

Educational outreach visits: effects on professional practice and health care outcomes

BACKGROUND

Outreach visits have been identified as an intervention that may improve the practice of health care professionals, in particular prescribing. This type of 'face to face' visit has been referred to as university-based educational detailing, public interest detailing, and academic detailing.

OBJECTIVES

To assess the effects of outreach visits on improving health professional practice or patient outcomes.

SEARCH STRATEGY

We searched MEDLINE up to March 1997, the Research and Development Resource Base in Continuing Medical Education, and reference lists of related systematic reviews and articles.

SELECTION CRITERIA

Randomised trials of outreach visits (defined as a personal visit by a trained person to a health care provider in his or her own setting). The participants were health care professionals.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Eighteen studies were included involving more than 1896 physicians. All of the outreach visit interventions consisted of several components, including written materials and conferences. Reminders or audit and feedback complemented some visits. In 13 studies, the targeted behaviours were prescribing practices. In three studies, the behaviours were preventive services, including counselling for smoking cessation. In two studies, the outreach visits were directed toward improving the general management of common problems encountered in general practice, including asthma, diabetes, otitis media, hypertension, anxiety, and acute bronchitis. All studies examined physician behaviour and in three studies other health professionals such as nurses, nursing home attendants or health care workers were targeted. Positive effects on practice were observed in all studies. Only one study measured a patient outcome. Few studies examined the cost effectiveness of outreach.

REVIEWER'S CONCLUSIONS

Educational outreach visits, particularly when combined with social marketing, appear to be a promising approach to modifying health professional behaviour, especially prescribing. Further research is needed to assess the effects of outreach visits for other aspects of practice and to identify key characteristics of outreach visits that are important to its success. The cost-effectiveness of outreach visits is not well evaluated.

Porcine heterografts in dermatologic surgery and reconstruction

BACKGROUND

Porcine heterografting is a method that can be used to reestablish the protective integrity of skin after cutaneous injury. These grafts may be used in an assortment of clinical situations for chronic and acute wounds, burn injury, and partial- or full-thickness areas of skin loss.

OBJECTIVE

The purpose of this article is to address the indications for using porcine heterografts in dermatologic surgery, the advantages and disadvantages of their use, and the technique of graft application.

METHODS

Indications for porcine heterografts and the methodology of graft application are discussed.

RESULTS

Porcine heterografts serve as a valuable tool in a variety of reconstruction settings in dermatologic surgery.

CONCLUSIONS

Heterografts provide an inexpensive method to facilitate wound care and promote healing, and serve as an effective repair option for a variety of surgical defects.

Audit and feedback versus alternative strategies: effects on professional practice and health care outcomes

BACKGROUND

Audit and feedback has been identified as having the potential to change the practice of health care professionals.

OBJECTIVES

To assess the effects of audit and feedback compared with other interventions in changing health professional practice and to assess whether the effectiveness of audit and feedback can be improved by modifying how it is done.

SEARCH STRATEGY

We searched MEDLINE up to June 1997, the Research and Development Resource Base in Continuing Medical Education, and reference lists of related systematic reviews and articles.

SELECTION CRITERIA

Randomised trials of audit and feedback (defined as any summary of clinical performance of health care over a specified period of time) compared with other interventions. The participants were health care providers responsible for patient care.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Twelve studies were included involving more than 2194 physicians. Seven trials with direct comparisons were included. The targeted behaviours were the management of low haemoglobin, the delivery of preventive care services (two studies), the management of high cholesterol, the performance of cervical smears, and the ordering of diagnostic tests (two studies). From the results of four trials, there is little evidence of a measurable effect of adding a complementary intervention such as a local consensus process to audit and feedback compared to audit and feedback alone. Two of three trials that compared audit and feedback to reminders reported that reminders were more effective in improving the delivery of some preventive services.

REVIEWER'S CONCLUSIONS

It is not possible to recommend a complementary intervention to enhance the effectiveness of audit and feedback. Reminders might be more effective than audit and feedback to improve the delivery of some preventive services but the results are not striking. Few trials have investigated the effect of varying different characteristics of the audit and feedback process. Consideration should be given to testing the effects of modifying important characteristics such as the content, source, timing, recipient and format.

Local opinion leaders: effects on professional practice and health care outcomes

BACKGROUND

Both the theory of diffusion of innovations and the social influences model of behaviour change suggest that using local opinion leaders to transmit norms and model appropriate behaviour may improve health professional practice.

OBJECTIVES

To assess the effects using local opinion leaders on the practice of health professionals or patient outcomes.

SEARCH STRATEGY

We searched MEDLINE to May 1998, the Research and Development Resource Base in Continuing Medical Education, and reference lists of related systematic reviews and articles.

SELECTION CRITERIA

Randomised trials of the use of local opinion leaders (defined as health professionals nominated by their colleagues as being educationally influential). The participants were health care professionals responsible for patient care.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed study quality.

MAIN RESULTS

Eight studies were included involving more than 296 health professionals. A variety of patient problems were targeted, including acute myocardial infarction, cancer pain, osteoarthritis, rheumatoid arthritis, chronic lung disease, vaginal birth after caesarean section, labour and delivery, and urinary catheter care. Six of seven trials that measured health professional practice demonstrated some improvement for at least one outcome variable, and in two trials, the results were statistically significant and clinically important. In three trials that measured patient outcomes, only one achieved an impact upon practice that was of practical importance: local opinion leaders were effective in improving the rate of vaginal birth after previous caesarean section.

REVIEWER'S CONCLUSIONS

Using local opinion leaders results in mixed effects on professional practice. However, it is not always clear what local opinion leaders do and replicable descriptions are needed. Further research is required to determine if opinion leaders can be identified and in which circumstances they are likely to influence the practice of their peers.

Reversible ischemic myelopathy during scoliosis surgery: a possible role for intravenous lidocaine

An unusual and previously unreported case of partially reversible ischemic myelopathy after limited unilateral segmental vessel ligation during scoliosis surgery is described. Intravenous lidocaine, used intraoperatively for its vasoactive properties, induced an immediate and meaningful recovery of neurologic function. The conceptual and pharmacologic basis for this intervention is discussed in view of this exceedingly rare complication of segmental vessel ligation.

Durable loss of a malignant T-cell clone in a stage IV cutaneous T-cell lymphoma patient treated with high-dose interferon and photopheresis

Stage IV cutaneous T-cell lymphoma (CTCL) has a notoriously poor prognosis and many treatment options exist. We describe the successful treatment of a case of stage IV CTCL with combination photopheresis and high-dose interferon alfa (IFNalpha). The patient was treated with combination therapy of monthly photopheresis and daily doses of IFNalpha up to 36 MU. Response to therapy was followed by clinical observation and Southern blot analysis for the detection of a malignant clone. The findings of this case were compared with others using a computer-based literature review. A complete clinical response lasting 64 months was achieved. Clinical relapse was preceded by an increase in the CD4/CD8 ratio and by reappearance of the T-cell receptor gene rearrangement. Combined photopheresis and high-dose IFNalpha led to a durable and sustained complete response in stage IV CTCL. CD4/CD8 ratios and T-cell gene rearrangements may be helpful in patient management.

Evaluating the effectiveness of 2 educational interventions in family practice

BACKGROUND

Structured feedback of information can produce change in physician behaviour. The objective of this study was to assess the effectiveness of 2 educational interventions for improving the quality of care provided by family physicians in Ontario: the Practice Assessment Report (PAR) and the Continuing Medical Education Plan (CMEP) with a follow-up visit by a mentor.

METHODS

The study was a randomized controlled trial. Physicians in the control group received only the PAR, whereas those in the experimental group received the PAR, CMEP and mentor interventions. The participants were 56 family physicians and general practitioners (27 in the PAR group and 29 in the CMEP group) in southern Ontario who agreed to participate in the interventions and provide data. A total of 2395 patients randomly sampled from the practices returned questionnaires and consented to have their medical records abstracted. The outcome measures were global scores in 4 areas--quality of care, charting, prevention and overall use of medications--and patient ratings of satisfaction with care and preventive practices. The measures were applied at the beginning (phase 1) and end (phase 2) of the study.

RESULTS

The mean global scores at the end of the study for the PAR group were 70.1% for quality of care, 84.7% for prevention, 77.7% for charting and 82.2% for overall use of medications. The corresponding scores for the CMEP group were 68.3%, 82.1%, 76.4% and 83.2%. In the patient satisfaction component, the personal care scores at phase 2 were 93.6% for the PAR group and 94.6% for the CMEP group. Examples of the scores for prevention for the PAR group were 98.3% for children's current immunization, 96.6% for blood pressure measured within the previous 5 years, 79.4% for referral of women of the appropriate age for mammography within the previous 2 years, and 58.4% for discussion about alcohol use. The corresponding scores for the CMEP group were 95.8%, 97.6%, 77.6% and 64.6%. The changes in mean scores between phase 1 and phase 2 ranged from -1.9 to 2.3 points. There were no significant differences between the 2 groups in phase 1 or phase 2 scores or in change in scores. A total of 64.3% of the physicians rated the PAR as useful, 26.5% found the CMEP to be useful, and 41.0% considered the mentor strategy to be a useful form of continuing medical education. Although changes in practice related to the PAR, CMEP or mentor were reported by some physicians, they were not related to chart audit or patient scores.

INTERPRETATION

Educational interventions based on quality-of-care assessments and directed to global improvements in quality of care did not result in improvements in the outcome measures. Educational interventions may have to be targeted to specific areas of the practice, with physicians being monitored and receiving ongoing feedback on their performance.

Conserved cysteines of the human immunodeficiency virus type 1 protease are involved in regulation of polyprotein processing and viral maturation of immature virions

We investigated the role of the two highly conserved cysteine residues, cysteines 67 and 95, of the human immunodeficiency virus type 1 (HIV-1) protease in regulating the activity of that protease during viral maturation. To this end, we generated four HIV-1 molecular clones: the wild type, containing both cysteine residues; a protease mutant in which the cysteine at position 67 was replaced by an alanine (C67A); a C95A protease mutant; and a double mutant (C67A C95A). When immature virions were produced in the presence of an HIV-1 protease inhibitor, KNI-272, and the inhibitor was later removed, limited polyprotein processing was observed for wild-type virion preparations over a 20-h period. Treatment of immature wild-type virions with the reducing agent dithiothreitol considerably improved the rate and extent of Gag processing, suggesting that the protease is, in part, reversibly inactivated by oxidation of the cysteine residues. In support of this, C67A C95A virions processed Gag up to fivefold faster than wild-type virions in the absence of a reducing agent. Furthermore, oxidizing agents, such as H2O2 and diamide, inhibited Gag processing of wild-type virions, and this effect was dependent on the presence of cysteine 95. Electron microscopy revealed that a greater percentage of double-mutant virions than wild-type virions developed a mature-like morphology on removal of the inhibitor. These studies provide evidence that under normal culture conditions the cysteines of the HIV-1 protease are susceptible to oxidation during viral maturation, thus preventing immature virions from undergoing complete processing following their release. This is consistent with the cysteines being involved in the regulation of viral maturation in cells under oxidative stress.