Relation of surgical volume to outcome in eight common operations: results from the VA National Surgical Quality Improvement Program

OBJECTIVE

To examine, in the Veterans Health Administration (VHA), the relation between surgical volume and outcome in eight commonly performed operations of intermediate complexity.

SUMMARY BACKGROUND DATA

In multihospital health care systems such as VHA, consideration is often given to closing low-volume surgical services, with the assumption that better surgical outcomes are achieved in hospitals with larger surgical volumes. Literature data to support this assumption in intermediate-complexity operations are either limited or controversial.

METHODS

The VHA National Surgical Quality Improvement Program data on nonruptured abdominal aortic aneurysmectomy, vascular infrainguinal reconstruction, carotid endarterectomy (CEA), lung lobectomy/pneumonectomy, open and laparoscopic cholecystectomy, partial colectomy, and total hip arthroplasty were used. Pearson correlation, analysis of variance, mixed effects hierarchical logistic regression, and automatic interaction detection analysis were used to assess the association of annual procedure/specialty volume with risk-adjusted 30-day death (and stroke in CEA).

RESULTS

Eight major surgical procedures (68,631 operations) were analyzed. No statistically significant associations between procedure or specialty volume and 30-day mortality rate (or 30-day stroke rate in CEA) were found.

CONCLUSIONS

In VHA hospitals, the procedure and surgical specialty volume in eight prevalent operations of intermediate complexity are not associated with risk-adjusted 30-day mortality rate from these operations, or with the risk-adjusted 30-day stroke rate from CEA. Volume of surgery in these operations should not be used as a surrogate for quality of surgical care.

The association between orthostatic hypotension and recurrent falls in nursing home residents

PURPOSE

Orthostatic hypotension is common among the elderly, but its relation to falls is not certain. We determined whether orthostatic hypotension, including its timing and frequency, was associated with falls in elderly nursing home residents.

SUBJECTS AND METHODS

We conducted a prospective study of 844 elderly (60 years of age and older), long-stay residents at 40 facilities that were part of a multistate nursing home chain. All subjects were able to maintain weight-bearing for at least 1 minute. Orthostatic hypotension was defined as a 20 mm Hg or greater decrease in systolic blood pressure from supine to standing, as measured after 1 or 3 minutes of standing on four occasions (before or after breakfast, or before or after lunch). The outcome was any subsequent fall during a mean of 1.2 years of follow-up.

RESULTS

Orthostatic hypotension was present (at least on one measurement) in 50% of the subjects but was not associated with subsequent falls. However, among subjects with a history of previous falls in the past 6 months, those with orthostatic hypotension had an increased risk of recurrent falls [adjusted relative risk (RR) = 2.1; 95% confidence interval (CI), 1.4 to 3.1 ]. The risk of subsequent falls was greatest in previous fallers who had orthostatic hypotension at two or more measurements (RR = 2.6; 95% CI, 1.7 to 4.6). The association between orthostatic hypotension and recurrent falls was independent of measured demographic or clinical risk factors for falls. The timing of orthostatic hypotension (before or after meals) did not affect the risk of falls.

CONCLUSIONS

Orthostatic hypotension is an independent risk factor for recurrent falls among elderly nursing home residents. Although the benefit of treating orthostatic hypotension will require further study, it may be prudent to identify high-risk residents and institute precautionary measures.

Comparison of surgical outcomes between teaching and nonteaching hospitals in the Department of Veterans Affairs

OBJECTIVE

To determine whether the investment in postgraduate education and training places patients at risk for worse outcomes and higher costs than if medical and surgical care was delivered in nonteaching settings.

SUMMARY BACKGROUND DATA

The Veterans Health Administration (VA) plays a major role in the training of medical students, residents, and fellows.

METHODS

The database of the VA National Surgical Quality Improvement Program was analyzed for all major noncardiac operations performed during fiscal years 1997, 1998, and 1999. Teaching status of a hospital was determined on the basis of a background and structure questionnaire that was independently verified by a research fellow. Stepwise logistic regression was used to construct separate models predictive of 30-day mortality and morbidity for each of seven surgical specialties and eight operations. Based on these models, a severity index for each patient was calculated. Hierarchical logistic regression models were then created to examine the relationship between teaching versus nonteaching hospitals and 30-day postoperative mortality and morbidity, after adjusting for patient severity.

RESULTS

Teaching hospitals performed 81% of the total surgical workload and 90% of the major surgery workload. In most specialties in teaching hospitals, the residents were the primary surgeons in more than 90% of the operations. Compared with nonteaching hospitals, the patient populations in teaching hospitals had a higher prevalence of risk factors, underwent more complex operations, and had longer operation times. Risk-adjusted mortality rates were not different between the teaching and nonteaching hospitals in the specialties and operations studied. The unadjusted complication rate was higher in teaching hospitals in six of seven specialties and four of eight operations. Risk adjustment did not eliminate completely these differences, probably reflecting the relatively poor predictive validity of some of the risk adjustment models for morbidity. Length of stay after major operations was not consistently different between teaching and nonteaching hospitals.

CONCLUSION

Compared with nonteaching hospitals, teaching hospitals in the VA perform the majority of complex and high-risk major procedures, with comparable risk-adjusted 30-day mortality rates. Risk-adjusted 30-day morbidity rates in teaching hospitals are higher in some specialties and operations than in nonteaching hospitals. Although this may reflect the weak predictive validity of some of the risk adjustment models for morbidity, it may also represent suboptimal processes and structures of care that are unique to teaching hospitals. Despite good quality of care in teaching hospitals, as evidenced by the 30-day mortality data, efforts should be made to examine further the structures and processes of surgical care prevailing in these hospitals.

Removal of gingival melanin pigmentation with the semiconductor diode laser: a case report

OBJECTIVE

This investigation was performed to evaluate the possibility of the removal of canine gingival melanin pigmentation with the semiconductor diode (SCD) laser in vivo.

SUMMARY BACKGROUND DATA

Recently, a semiconductor laser, which can ablate soft tissue, has been developed. It is already used in dentistry as well as in medicine.

METHODS

The SCD laser was irradiated on the pigmented area of canine gingival surface with the irradiation output of 3W. The effect of the SCD laser irradiation was evaluated at the two intervals: immediately after irradiation and at 3 weeks following irradiation. In addition, histological examination was performed before irradiation and at the same intervals from the biopsies (4 microm) of unlased and lased areas.

RESULTS

The SCD laser was effective in removing melanin pigmentation. In histological examination, neither inflammatory cell nor any tissue damage was observed with hematoxylin-eosin staining. At 3 weeks, there was a continuous healing process with the proliferation of squamous epithelial cells.

CONCLUSIONS

SCD laser irradiation can be considered an alternative procedure for removal of melanin pigmentation.

A longitudinal study of risk factors associated with the formation of pressure ulcers in nursing homes

OBJECTIVE

To determine risk factors associated with the formation of stage II-IV pressure ulcers in nursing homes.

DESIGN

Since the incidence rate for pressure ulcer formation varies among nursing homes, the homes were divided into tertiles based on these rates. Pooled logistic regression was used to model which factors are associated with the formation of pressure ulcers in both high and low incidence homes.

SETTING

78 National HealthCorp nursing homes.

SUBJECTS

We studied 4232 nursing home residents free of pressure ulcers on admission to a nursing facility and at 3-months follow-up. All remained in the home for at least 3 additional months to a maximum of 21 months.

MEASUREMENTS

The effects of age, gender, race, antipsychotic drug use, urinary incontinence, fecal incontinence, body mass index, diabetes mellitus, disorientation, ambulation, physical restraints, activities of daily living of bathing, feeding, or transferring, and nursing home bed size on the formation of a stage II-IV pressure ulcer while the subject was a resident in the nursing home were studied.

MAIN RESULTS

Significant factors associated with the formation of pressure ulcers in high incidence homes (21-month incidence = 19.3%) were ambulation difficulty (OR = 3.3; CI = 2.0, 5.3), fecal incontinence (OR = 2.5; CI = 1.6, 4.0), diabetes mellitus (OR = 1.7; CI = 1.2, 2.5), and difficulty feeding oneself (OR = 2.2; CI = 1.5, 3.3). In the low incidence homes (21-month incidence = 6.5%), significant factors associated with pressure ulcer incidence were ambulation difficulty (OR = 3.6; CI = 1.7, 7.4), difficulty feeding oneself (OR = 3.5; CI = 2.0, 6.3), and male gender (OR = 1.9; CI = 1.2, 3.6).

CONCLUSIONS

Although low and high incidence homes share similar risk factors, such as ambulation and feeding activities of daily living, the main difference was that diabetes and fecal incontinence played a major role only in high risk homes, while male gender was an important discriminator only in low incidence homes. Yet, it is unclear if these factors explain the three-fold difference in the incidence rates for pressure ulcers in these facilities. Baseline or resident clinical characteristic differences of any one factor between the high and low incidence homes varied by no more than 5%. While we identified certain conditions which are associated with pressure ulcer formation, there may be unknown or unmeasured facility effects in addition to the characteristics of a given resident in a particular home.

Effects of Er,Cr:YSGG laser irradiation in human enamel and dentin: ablation and morphological studies

OBJECTIVE

This investigation was performed to determine quantitatively the ranges of ablation and to evaluate the morphological changes in human enamel and dentin irradiated by Er,Cr:YSGG laser with or without water spray.

SUMMARY BACKGROUND DATA

Recently, Er,Cr:YSGG laser has been introduced in dental clinics to remove carious dental hard tissues in anticipation of replacing the high-speed dental drill.

METHODS

A total of 40 extracted human teeth were used in this study. An Er,Cr:YSGG laser was used to ablate human dental hard tissues with the output powers of 3 to 6 W. Ablation extent with or without water spray at different output powers was measured, and the morphological changes on enamel and dentin were also investigated by stereoscopy and scanning electron microscopy (SEM).

RESULTS

The irradiation with water spray significantly (p < 0.001) increased the ablation depths compared to those irradiated without water mist. Morphological findings by SEM indicated that when irradiated without water spray, carbonization with brown or dark color was recognized in enamel or dentin, respectively. In addition, cavities with a molten lava-like appearance were produced and an irregular structure with many microholes was observed in dentin.

CONCLUSIONS

These results suggest that during the Er,Cr:YSGG laser irradiation, water spray directed at the ablation sites increases the ablation depths and water plays an important role as an initiator of the ablation of dental hard tissues.

Ablation depths and morphological changes in human enamel and dentin after Er:YAG laser irradiation with or without water mist

OBJECTIVE

This investigation was performed quantitatively to determine the ranges of ablation and to evaluate the morphological changes in human enamel and dentin irradiated by Er:YAG laser with or without water mist.

SUMMARY BACKGROUND DATA

Recently, several infrared lasers have been introduced in the dental clinic to remove carious dental hard tissues in anticipation of replacing the high-speed dental drill. Among them, the Er:YAG laser has shown the most promise for hard tissue ablation.

METHODS

An Er:YAG laser was used to ablate human dental hard tissues using a pulse energy that ranged from 100 to 400 mJ at a frequency of 2 Hz for 5 seconds. Ablation rates with or without water mist at different pulse energies were measured, and the morphological changes on enamel and dentin were also investigated by stereomicroscopy and scanning electron microscopy (SEM).

RESULTS

The relationship between ablation depths and energies was almost linear at both enamel and dentin samples. The irradiation with water mist reduced the ablation depths, but only minimally, when compared to those irradiated without water mist. Morphological findings by SEM indicated that Er:YAG laser irradiation with water mist could produce the cavities without signs of thermal damage to the surrounding enamel and dentin.

CONCLUSIONS

The results of this study suggest that addition of a fine water mist directed at the ablation sites does not greatly decrease the ablation, and does not cause any carbonization and melting in the surrounding dental hard tissues.

A systematic review of published evidence on intervention impact on condom use in sub-Saharan Africa and Asia

OBJECTIVE

There has been much debate about the value of condoms in HIV/STI programming. This should be informed by evidence about intervention impact on condom use, but there is limited compiled literature. This review aims to quantify intervention impact on condom use in sub-Saharan Africa and Asia, in different types of partnership.

METHODS

A systematic review was conducted of papers published between 1998 and 2006 presenting evaluations of interventions involving condom promotion in sub-Saharan Africa and Asia. Data on reported postintervention levels of condom use, and various measures of changes in condom use, by partnership type, were compiled.

RESULTS

A total of 1374 abstracts were identified. Sixty-two met the inclusion criteria (42 reporting significant increases in condom use): 44 from sub-Saharan Africa and 18 from Asia. Many (19) reported on condom use in commercial sex (15 significant), six on use with casual partners (three significant), 11 on use in marital/steady partnerships (nine significant), 14 on use by youths (eight significant) and 20 combined partnership types (11 significant). There is substantial evidence of interventions targeted at sex workers and clients achieving large increases in condom use. Far less evidence exists of intervention impact on condom use in casual relationships. In primary partnerships, postintervention condom use was low unless one partner was knowingly HIV-infected or at high-risk, or avoiding pregnancy. Evaluations of interventions targeting youths recorded limited increases in condom use.

CONCLUSIONS

The findings illustrate the range of evidence about postintervention condom use in different partnerships, and how patterns of use are influenced by partnership type and perceptions of risk. Where possible, intervention studies should also assess biological endpoints, since prevention of infection is the measure of most interest in the evaluation of condom promotion interventions.

Rice-powder electrolyte solution as oral-therapy in diarrhoea due to Vibrio cholerae and Escherichia coli

124 patients with acute diarrhoea due to Vibrio cholerae or Escherichia coli were treated with either the standard sucrose-electrolyte solution or a cereal-based electrolyte solution, containing 30 g rice powder per litre and electrolytes as recommended by the World Health Organisation. The treatments were compared by measuring the rate of purging, change in body weight, serum specific gravity, urine output, and post-hydrolysis sugar content in the stool. The proportions of successfully treated patients in the rice-powder group were 80% for cholera patients and 88% for E. coli patients--no different from those in patients receiving the sucrose-electrolyte solution. Failure was due to rates of purging that exceeded the patient's ability to drink enough replacement solution. This study suggests that a rice-powder electrolyte solution is efficient and safe to use as a rehydrating oral fluid in acute diarrhoea.

Interleukin-13 but not interleukin-4 prolongs eosinophil survival and induces eosinophil chemotaxis

The effects of recombinant human (rh) interleukin (IL)-4 or rhIL-13 on survival, and chemotactic activity of human eosinophils were examined. Only rhIL-13 prolonged eosinophil survival in a dose-dependent manner above 3 ng/ml. Eosinophil survival induced by rhIL-13 was inhibited by monoclonal antibodies (mAbs) against IL-3 (p < 0.01) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (p < 0.05), suggesting that rhIL-13 induced IL-3 and GM-CSF production from eosinophils and an autocrine mechanism is responsible for the eosinophil survival. The effects of rhIL-13 on eosinophil chemotactic activity were also examined. rhIL-13 showed chemotactic activity for eosinophils in a dose-dependent manner. Checkerboard analysis revealed that eosinophil migration was dependent on the concentration gradient, confirming that rhIL-13 is a chemotactic factor. rhIL-4 showed no effects. IL-13 may play an important role in the survival and recruitment of eosinophils in allergic diseases.

Primordial GATA6 macrophages function as extravascular platelets in sterile injury

Most multicellular organisms have a major body cavity that harbors immune cells. In primordial species such as purple sea urchins, these cells perform phagocytic functions but are also crucial in repairing injuries. In mammals, the peritoneal cavity contains large numbers of resident GATA6⁺ macrophages, which may function similarly. However, it is unclear how cavity macrophages suspended in the fluid phase (peritoneal fluid) identify and migrate toward injuries. In this study, we used intravital microscopy to show that cavity macrophages in fluid rapidly form thrombus-like structures in response to injury by means of primordial scavenger receptor cysteine-rich domains. Aggregates of cavity macrophages physically sealed injuries and promoted rapid repair of focal lesions. In iatrogenic surgical situations, these cavity macrophages formed extensive aggregates that promoted the growth of intra-abdominal scar tissue known as peritoneal adhesions.

Caries-preventive effect of Er:YAG laser irradiation with or without water mist

OBJECTIVE

This investigation was performed to evaluate the effect of Er:YAG laser irradiation on the acquired acid resistance of sound dental hard tissues to artificial caries formation by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro.

BACKGROUND DATA

Although an Er:YAG laser has shown the most promise for hard tissue ablation, there have not been any dissolution studies to determine if this laser is suitable for caries preventive treatments.

METHODS

An Er:YAG laser was used to irradiate the enamel and dentin samples from 20 extracted human molars at 400 mJ pulse energy with or without water mist. Samples were subjected to 2 microL of 0.1 M lactic acid solution (pH 4.8) for 24 hours at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by SEM.

RESULTS

The lowest mean Ca2+ ppm was recorded in the samples irradiated without water mist, in those by irradiated with water mist, and in the unlased samples. SEM observation showed that the lased areas had melted and seemed to be thermally degenerated when irradiated without water mist. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged.

CONCLUSIONS

The results of this study suggest that Er:YAG laser irradition with and without water mist appears to be more effective for caries prevention.

Population pharmacokinetics. A regulatory perspective

The application of population approaches to drug development is recommended in several US Food and Drug Administration (FDA) guidance documents. Population pharmacokinetic (and pharmacodynamic) techniques enable identification of the sources of inter- and intra-individual variability that impinge upon drug safety and efficacy. This article briefly discusses the 2-stage approach to the estimation of population pharmacokinetic parameters, which requires serial multiple measurements on each participant, and comprehensively reviews the nonlinear mixed-effects modelling approach, which can be applied in situations where extensive sampling is not done on all or any of the participants. Certain preliminary information, such as the compartment model used in describing the pharmacokinetics of the drug, is required for a population pharmacokinetic study. The practical design considerations of the location of sampling times, number of samples/participants and the need to sample an individual more than once should be borne in mind. Simulation may be useful for choosing the study design that will best meet study objectives. The objectives of the population pharmacokinetic study can be secondary to the objectives of the primary clinical study (in which case an add-on population pharmacokinetic protocol may be needed) or primary (when a stand-alone protocol is required). Having protocols for population pharmacokinetic studies is an integral part of 'good pharmacometric practice'. Real-time data assembly and analysis permit an ongoing evaluation of site compliance with the study protocol and provide the opportunity to correct violations of study procedures. Adequate policies and procedures should be in place for study blind maintenance. Real-time data assembly creates the opportunity for detecting and correcting errors in concentration-time data, drug administration history and covariate data. Population pharmacokinetic analyses may be undertaken in 3 interwoven steps: exploratory data analysis, model development and model validation (i.e. predictive performance). Documentation for regulatory purposes should include a complete inventory of key runs in the analyses undertaken (with flow diagrams if possible), accompanied by articulation of objectives, assumptions and hypotheses. Use of diagnostic analyses of goodness of fit as evidence of reliability of results is advised. Finally, the use of stability testing or model validation may be warranted to support label claims. The opinions expressed in this article were revised by incorporating comments from various sources and published by the FDA as 'Guidance for Industry: Population Pharmacokinetics' (see the FDA home page http:/(/)www.fda.gov for further information).

The prevalence of potentially remediable urinary incontinence in frail older people: a study using the Minimum Data Set

OBJECTIVES

To use the Minimum Data Set (MDS) to describe the frequency and correlates of potentially treatable causes of urinary incontinence among a representative sample of American nursing home residents. To describe current management practices of urinary incontinence in the same population.

DESIGN

Cross-sectional study using the dataset that was part of the Health Care Financing Administration (HCFA) evaluation of the MDS.

SETTING

270 Medicaid-certified nursing homes in 10 states.

PARTICIPANTS

A total of 2014 nursing home residents 60 years or older (mean = 84.3 +/- 8.7), 75.5% women, 81.9% white, who lived in a nursing home during the fall of 1990 were randomly selected to sample a fixed number of residents for each facility based on facility size.

MEASUREMENTS

Incontinence was defined as the presence of at least two episodes of urinary leakage per week in the previous 2 weeks. Management techniques (toileting, pads/briefs, catheters) were those listed in the MDS. Potentially remediable causes of urinary incontinence available in the MDS were: medications (antipsychotics, antidepressants, and antianxiety/hypnotics); congestive heart failure; diabetes mellitus; pedal edema; delirium; depression; and impairments in activities of daily living (ADLs) (transferring, locomotion, dressing, toileting; bedrails; trunk restraints; and chair restraints).

RESULTS

Forty-nine percent of residents were incontinent. Of these, 84.0% were managed by pads/briefs, 38.7% by scheduled toileting, 3.5% by indwelling catheter, and 1.2% by external catheter. Of the potentially reversible causes, bivariate analysis revealed associations (P < .1) with use of antidepressants, antipsychotics, and antianxiety/hypnotics; delirium; bedrails; trunk restraints; chair restraints; and ADL impairment. Dementia was also associated with incontinence (P < .1). Multivariate analysis revealed that urinary incontinence was independently associated with impairment in ADLs (OR = 4.2; CI = 3.2,5.6), dementia (OR = 2.3;CI = 1.8,3.0), restraints-trunk (OR = 1.7; CI = 1.5,2.0), chair (OR = 1.4; CI = 1.2,1.6), bedrails (OR = 1.3; CI = 1.1,1.5), and use of antianxiety/hypnotic medications (OR = .7;CI = .5,1.0) (all P < .04).

CONCLUSIONS

Current management practices for urinary incontinence are inconsistent with advocated guidelines. These data also confirm the association between incontinence and several potentially remediable conditions and suggest that, even in the nursing home setting, urinary incontinence may respond to efforts to improve conditions not directly related to bladder function. This study underscores the need to examine the impact on urinary incontinence of strategies to address such conditions.

Predicting the pain continuum after adolescent idiopathic scoliosis surgery: A prospective cohort study

BACKGROUND

Chronic postsurgical pain (CPSP) affects half a million children annually in the United States, with dire socioeconomic consequences, including long-term disability into adulthood. The few studies of CPSP in children are limited by sample size, follow-up duration, non-homogeneity of surgical procedure and factors evaluated.

METHODS

In a prospective study of 144 adolescents undergoing a single major surgery (spine fusion), we evaluated demographic, perioperative, surgical and psychosocial factors as predictors of a continuum of postsurgical pain: immediate, pain maintenance at 2-3 months (chronic pain/CP) and persistence of pain a year (persistent pain/PP) after surgery.

RESULTS

We found an incidence of 37.8% and 41.8% for CP and PP. CP and acute pain were both significant predictors for developing PP (p-value <0.001 and 0.003). Preoperative pain and higher postoperative opioid requirement was significantly associated with CP (p = 0.015, p = 0.002), while Childhood Anxiety Sensitivity Index (p = 0.002) and surgical duration (p = 0.014) predicted PP. The final regression models had reasonable predictive accuracy (c-statistic of 0.73 and 0.83 for CP and PP, respectively). Anxiety scores and catastrophizing for child and parent were found to be significantly correlated (p = 0.005, p = 0.013 respectively). Pain trajectories revealed that 65% of patients who developed PP reported CP and high pain trends; however, 33% of those who developed PP could not be identified using solely pain criteria.

CONCLUSION

Persistent postsurgical pain in children is a significant problem. It can be predicted in part by combinations of psychological and clinical variables, which may provide evidence-based measures to prevent development of CPSP in the future.

SIGNIFICANCE

In a homogeneous cohort of adolescents undergoing spine fusion, we report a high incidence of persistent postsurgical pain (41.8%) predicted by child anxiety, perioperative pain, and surgical duration. Our results stress timely preventive and therapeutic strategies.

An analysis of the safety of the single dose, two drug regimens used in programmes to eliminate lymphatic filariasis

This review of the safety of the co-administration regimens to be used in programmes to eliminate lymphatic filariasis (albendazole + ivermectin or albendazole + diethylcarbamazine [DEC]) is based on 17 studies conducted in Sri Lanka, India, Haiti, Ghana, Tanzania, Kenya, Ecuador, the Philippines, Gabon, Papua New Guinea, and Bangladesh. The total data set comprises 90,635 subject exposures and includes individuals of all ages and both genders. Results are presented for hospital-based studies, laboratory studies, active surveillance of microfilaria-positive and microfilaria-negative individuals, and passive monitoring in both community-based studies and mass treatment programmes of individuals treated with albendazole (n = 1538), ivermectin (9822), DEC (576), albendazole + ivermectin (7470), albendazole + DEC (69,020), or placebo (1144). The most rigorous monitoring, which includes haematological and biochemical laboratory parameters pre- and post-treatment, provides no evidence that consistent changes are induced by any treatment; the majority of abnormalities appear to be sporadic, and the addition of albendazole to either ivermectin or DEC does not increase the frequency of abnormalities. Both DEC and ivermectin show, as expected, an adverse event profile compatible with the destruction of microfilariae. The addition of albendazole to either single-drug treatment regimen does not appear to increase the frequency or intensity of events seen with these microfilaricidal drugs when used alone. Direct observations indicated that the level of adverse events, both frequency and intensity, was correlated with the level of microfilaraemia. In non microfilaraemic individuals, who form 80-90% of the 'at risk' populations to be treated in most national public health programmes to eliminate lymphatic filariasis (LF), the event profile with the compounds alone or in combination does not differ significantly from that of placebo. Data on the use of ivermectin + albendazole in areas either of double infection (onchocerciasis and LF), or of loiais (with or without concurrent LF) are still inadequate and further studies are needed. Additional data are also recommended for populations infected with Brugia malayi, since most data thus far derive from populations infected with Wuchereria bancrofti.

Atomic analysis and knoop hardness measurement of the cavity floor prepared by Er,Cr:YSGG laser irradiation in vitro

In the present study, the compositional changes and knoop hardness of the cavity floor prepared by Er,Cr:YSGG laser irradiation was compared with that of the conventional bur cavity. Fifteen laser and 15 bur cavities were cross-sectioned, and subjected to atomic analysis by SEM-EDX and knoop hardness test. Statistical analyses were performed using the Mann-Whitney U-test; a value of P < 0.01 was considered significant. Surface characteristics of the prepared cavities were also investigated by light microscopy and scanning electron microscopy (SEM). The results showed that the quantities of Ca (Ca weight %) and P (P weight %) were increased significantly in the laser cavity floor but no significant differences were found between the Ca/P ratio and knoop hardness number of laser and bur cavities. The SEM observation revealed that the lased cavity surface was irregular and there was also the absence of a smear layer; the orifice of dentinal tubules was exposed. Er,Cr:YSGG laser device is considered as one of the most effective and safe devices for cavity preparation because of its many advantages. This includes easy delivery system, minimal thermal damage to the surrounding tissues, minimal thermal-induced changes of dental hard tissue compositions, and favourable surface characteristic.

Responses to the major acrolein-derived deoxyguanosine adduct in Escherichia coli

Acrolein, a reactive alpha,beta-unsaturated aldehyde found ubiquitously in the environment and formed endogenously in mammalian cells, reacts with DNA to form an exocyclic DNA adduct, 3H-8-hydroxy-3-(beta-D-2'-deoxyribofuranosyl)-5,6,7,8-tetrahydropyrido[3,2-a]purine-9-one (gamma-OH-PdG). The cellular processing and mutagenic potential of gamma-OH-PdG have been examined, using a site-specific approach in which a single adduct is embedded in double-strand plasmid DNA. Analysis of progeny plasmid reveals that this adduct is excised by nucleotide excision repair. The apparent level of inhibition of DNA synthesis is approximately 70% in Escherichia coli DeltarecA, uvrA. The block to DNA synthesis can be overcome partially by recA-dependent recombination repair. Targeted G --> T transversions were observed at a frequency of 7 x 10(-4)/translesion synthesis. Inactivation of polB, dinB, and umuD,C genes coding for "SOS" DNA polymerases did not affect significantly the efficiency or fidelity of translesion synthesis. In vitro primer extension experiments revealed that the Klenow fragment of polymerase I catalyzes error-prone synthesis, preferentially incorporating dAMP and dGMP opposite gamma-OH-PdG. We conclude from this study that DNA polymerase III catalyzes translesion synthesis across gamma-OH-PdG in an error-free manner. Nucleotide excision repair, recombination repair, and highly accurate translesion synthesis combine to protect E. coli from the potential genotoxicity of this DNA adduct.

Tobacco smoke: a critical etiological factor for vascular impairment at the blood-brain barrier

Active and passive tobacco smoke are associated with the dysfunction of endothelial physiology and vascular impairment. Studies correlating the effects of smoking and the brain microvasculature at the blood-brain barrier (BBB) level have been largely limited to few selective compounds that are present in the tobacco smoke (TS) yet the pathophysiology of smoking has not been unveiled. For this purpose, we characterized the physiological response of isolated human brain microvascular endothelial cells (HBMEC) and monocytes to the exposure of whole soluble TS extract. With the use of a well established humanized flow-based in vitro blood-brain barrier model (DIV-BBB) we have also investigated the BBB physiological response to TS under both normal and impaired hemodynamic conditions simulating ischemia. Our results showed that TS selectively decreased endothelial viability only at very high concentrations while not significantly affecting that of astrocytes and monocytes. At lower concentrations, despite the absence of cytotoxicity, TS induced a strong vascular pro-inflammatory response. This included the upregulation of endothelial pro-inflammatory genes, a significant increase of the levels of pro-inflammatory cytokines, activated matrix metalloproteinase, and the differentiation of monocytes into macrophages. When flow-cessation/reperfusion was paired with TS exposure, the inflammatory response and the loss of BBB viability were significantly increased in comparison to sham-smoke condition. In conclusion, TS is a strong vascular inflammatory primer that can facilitate the loss of BBB function and viability in pathological settings involving a local transient loss of cerebral blood flow such as during ischemic insults.

A study on surface roughness and microleakage test in cavities prepared by Er:YAG laser irradiation and etched bur cavities

The purposes of this study were to investigate the surface morphology, suface roughness of cavities prepared by Er:YAG laser irradiation, and compared the microleakage degree after composite resin restoration with etched bur cavities, in vitro. In each of the 30 human extracted teeth, two shallow cavities were prepared; one prepared with the Er:YAG laser system on the buccal surface, and one produced on the lingual (palatal) surface with a high-speed turbine. Five cavities from each group were investigated by scanning electron microscopy (SEM), and five were subjected to surface roughness analysis by a colour laser three-dimensional (3D) microscope. The remaining cavities were filled with a composite resin and subjected to a microleakage test under thermocycling. Only bur cavities were acid-etched before filling. Statistical analysis was performed using the Mann-Whitney U test; a value of p <0.01 was considered significant. Morphologically, the prepared cavities showed an irregular surface with the absence of a debris-like smear layer; enamel prisms and opening of dentinal tubules were recognised. Surface roughness was significantly increased with the laser system. Microleakage test revealed no significant differences between the laser and bur cavities. Crosscut sections of the cavities with no microleakage showed no gap at the interface. Laser cavity may facilitate good adaptation of composite resin with enamel and dentine, because an increase of surface roughness and the openings of dentinal tubules may facilitate the formation of a hybrid zone, since a primer and an adhesive can penetrate the surface better when the smear layer is removed. It can be concluded that shallow cavity prepared by Er:YAG laser is capable of decreasing microleakage of composite resin restorations, and its efficiency is similar to etched bur cavities.

Is magnetic resonance imaging (MRI) necessary to exclude occult hip fracture?

The possibility of occult hip fracture in older patients after a fall is a common problem in emergency and orthopaedic departments. Magnetic resonance imaging (MRI) scanning is the best investigation, but is expensive and may be difficult to obtain. The value of various clinical signs to determine which patients are at risk of occult hip fracture has not been reported. We reviewed all patients who had MRI scan for suspected hip fractures but had normal initial X-rays over a 6-year period. We identified 76 patients. Twelve patients were excluded. Two patients had MRI scan for suspected stress fracture and two patients had metastatic fractures. Eight patients had inadequate or untraceable clinical notes. Each patient's personal details, mobility, independence and detail clinical details were recorded. Following case review of 64 patients we excluded 5 patients with associated osteoarthritis of the hip joint, 1 patient with fibromyalgia and 1 patient with pre-existing multiple myeloma. Thirty-five patients had occult proximal femoral fractures. Of them four patients had isolated pubic ramus fractures and five patients had isolated greater trochanter fractures. Twenty-two patients had no fracture. The value of the individual tests was evaluated using Fisher exact and chi square analysis; with Bonferroni correction for multiple comparisons (10 tests) p<0.005 was deemed significant. Pain on axial loading of the limb and pre-fracture restricted patient mobility were both associated with the presence of a fracture (p<0.005). Both factors had identical positive predictive value=0.76, a negative predictive value=0.69 and post-test probability of disease given a negative test=0.30. Predictive values remained the same when both factors were considered together. Patients who were independently mobile before the fall and who do not have pain on axial compression of the limb are less likely to have a fracture, but these signs alone or in combination do not exclude a fracture. The clinical signs investigated cannot distinguish between patients with and without a hip fracture, and MRI scanning is necessary to establish whether some patients have an occult fracture.

Longitudinal weight changes, length of survival, and energy requirements of long-term care residents with dementia

OBJECTIVE

We hypothesized that institutionalized patients with dementia, who frequently have feeding problems and require supervised and assisted feeding, would lose more weight during their residency than nondemented, independently functioning residents and have compromised survival. To test this hypothesis, we examined the survival and longitudinal changes in weight of two cohorts of institutionalized residents with dementia and compared these cohorts with a cohort of nondemented residents. We also measured the resting energy expenditures of a subset of the subjects with dementia as an indicator of their energy needs.

DESIGN

A longitudinal cohort study with retrospective baseline chart review and subsequent follow-up of monthly weights and mortality over 4 years.

SETTING

A 725-bed long-term care institution with specified levels of care.

SUBJECTS

Two cohorts of residents with dementia, one consisting of subjects who required total care throughout their institutional stay (n = 31) and another group who did not initially require total care (n = 48); these were compared with a cohort with normal mentation who were functionally independent in their daily activities (n = 26). The total number of subjects was 105.

MEASUREMENTS

Demographics, medical problems, and medications by chart review; functional and mental status evaluations; longitudinal monthly weights and mortality for the 48-month study period; and resting energy expenditures by indirect calorimetry.

MAIN RESULTS

Residents with dementia had lower weights on admission and throughout their stay than nondemented, independently functioning residents, and they were more likely to have a weight loss of 10 lbs or more at some point during the 4-year study period. However, their mean weights did not change during the study period. The mean survival from admission of those demented residents who died was more than 3 years. Resting energy expenditures of women residents with advanced dementia were 12% lower than predicted from the Harris Benedict equations.

CONCLUSION

Dementia is not necessarily associated with unremitting weight loss during institutionalization despite the frequent occurrence of feeding difficulties and temporary weight loss. This may be caused partly by the lower than expected resting energy expenditures and, hence, energy needs of affected residents as their dementia progresses. Demented residents weighed significantly less than nondemented, independently functioning residents throughout their institutional stay. Nevertheless, nursing staff are able to maintain weight and survival for extended periods even in very impaired residents.

A study on acquired acid resistance of enamel and dentin irradiated by Er,Cr:YSGG laser

OBJECTIVE

This investigation was performed to evaluate the acid resistance of lased enamel and dentin by Er,Cr:YSGG laser to artificial caries-like lesions by spectrophotometry, and the ultrastructure of lased areas was investigated by scanning electron microscopy (SEM) in vitro.

BACKGROUND DATA

In recent years, many studies have been performed to evaluate the effects of Er,Cr:YSGG laser on dental hard tissues. However, there have been only a few studies to determine if this laser is suitable for caries preventive treatments.

METHODS

An Er,Cr:YSGG laser was used to irradiate the enamel or dentin samples from 30 extracted human molars at 6 W (67.9 J/cm2) or 5 W (56.6 J/cm2) pulse energy, respectively, with or without water mist. Samples were subjected to 2 microl of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 degrees C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometery, and the morphological changes were investigated by SEM.

RESULTS

The lowest mean Ca2+ ppm was recorded in the lased samples. SEM observation showed that the lased areas were melted and seemed to be thermally degenerated. After acid demineralization, the thermally degenerated enamel or dentin surfaces were almost unchanged.

CONCLUSIONS

The results of this study suggested that Er,Cr:YSGG laser irradiation with and without water mist appears to be effective for increasing acid resistance.