Amorphous and crystalline phases in thermal quench simulations of alumina

The authors report molecular dynamics simulations of alumina (Al2O3) during crystallization from the melt. Using liquid quench methods, they investigate the effect of cooling rate on the structural evolution of the alpha, kappa, and the bixbyite phases. A critical temperature window is identified, where the time spent in this window is crucial in determining the extent to which the systems approach crystallinity. A strong dependence is observed between the final structure and the quench rate, which is most pronounced for the alpha phase and to lesser extent for the other phases. The results show that the different phases have different tendencies to crystallize that are determined by energetics, complexity of crystal structure, and the number of metastable states.

Assessment of behavioral and psychological symptoms of dementia

In spite of their prevalence and persistence, why are behavioral and psychological symptoms of dementia difficult for clinicians to assess and manage? This paper provides an overview of the methodological challenges encountered in measuring behavioral disturbances of dementia. Specifically, conceptual constructs of behavioral and psychological symptoms of dementia, the strengths and weaknesses of the currently existing rating instruments, analytic methodologies, and the utility of technological devices are outlined in the service of formulating future directions in behavioral and psychological symptoms of dementia assessment research.

Novel, non-steroidal, selective androgen receptor modulators (SARMs) with anabolic activity in bone and muscle and improved safety profile

A novel approach to the treatment of osteoporosis in men, and possibly women, is the development of selective androgen receptor modulators (SARMs) that can stimulate formation of new bone with substantially diminished proliferative activity in the prostate, as well as reduced virilizing activity in women. Over the last several years, we have developed a program to discover and develop novel, non-steroidal, orally-active selective androgen receptor modulators (SARMs) that provide improved therapeutic benefits and reduce risk and side effects. In recent studies, we have used a skeletally mature orchiectomized (ORX) male rat as an animal model of male hypogonadism for assessing the efficacy of LGD2226, a nonsteroidal, non-aromatizable, and non-5alpha-reducible SARM. We assessed the activity of LGD2226 on bone turnover, bone mass and bone strength, and also evaluated the effects exerted on classic androgen-dependent targets, such as prostate, seminal vesicles and muscle. A substantial loss of bone density was observed in ORX animals, and this loss was prevented by SARMs, as well as standard androgens. Biochemical markers of bone turnover revealed an early increase of bone resorption in androgen-deficient rats that was repressed in ORX animals treated with the oral SARM, LGD2226, during a 4-month treatment period. Differences in architectural properties and bone strength were detected by histomorphometric and mechanical analyses, demonstrating beneficial effects of LGD2226 on bone quality in androgen-deficient rats. Histomorphometric analysis of cortical bone revealed distinct anabolic activity of LGD2226 in periosteal bone. LGD2226 was able to prevent bone loss and maintain bone quality in ORX rats by stimulating bone formation, while also inhibiting bone turnover. LGD2226 also exerted anabolic activity on the levator ani muscle. Taken together, these results suggest that orally-active, non-steroidal SARMs may be useful therapeutics for both muscle and bone in elderly hypogonadal men through their anabolic activities. Since SARMs both prevent bone loss, and also stimulate formation of new bone, they may have significant advantages relative to currently used anti-resorptive therapies. Coupled with their activity in muscle and their ability to maintain or restore libido, they offer new therapeutic approaches for male and female hormone replacement.

Mechanisms of hormonal prevention of breast cancer

Reproductive history is a consistent risk factor for human breast cancer. Epidemiological studies have repeatedly demonstrated that early age of first pregnancy is a strong protective factor against breast cancer and provides a physiologically operative model to achieve a practical mode of prevention. In rodents, the effects of full-term pregnancy can be mimicked by a three-week exposure to low doses of estrogen and progesterone. Neither hormone alone is sufficient to induce protection. The cellular and molecular mechanisms that underlie hormone-induced refractoriness are largely unresolved. Our recent studies have demonstrated that an early cellular response that is altered in hormone-treated mammary cells is the initial proliferative burst induced by the chemical carcinogen methylnitrosourea. The decrease in proliferation is also accompanied by a decrease in the ability of estrogen receptor-positive cells to proliferate. RNA expression of several mammary cell-cycle-related genes is not altered in hormone-treated mice; however, immunohistochemical assays demonstrate that the protein level and nuclear compartmentalization of the p53 tumor suppressor gene are markedly upregulated as a consequence of hormone treatment. These results support the hypothesis that hormone stimulation, at a critical period in mammary development, results in cells with persistent changes in the intracellular regulatory loops governing proliferation and response to DNA damage. A corollary to this hypothesis is that the genes affected by estrogen and progesterone are independent of alveolar differentiation-specific genes. Suppressive subtractive hybridization-PCR methods have identified several genes that are differentially expressed as a consequence of prior estrogen and progesterone treatment. Future experiments are aimed at determining the mechanisms of hormone-induced upregulation of p53 protein expression as part of the overall goal of identifying and functionally characterizing the genes responsible for the refractory phenotype.

The 5-HTTPR polymorphism confers liability to a combined phenotype of psychotic and aggressive behavior in Alzheimer disease

BACKGROUND

Psychotic symptoms in subjects with Alzheimer disease (AD+psychosis, AD+P) are a marker for a distinct phenotype characterized by more rapid cognitive and functional decline and a liability to aggressive behaviors. We recently found that AD subjects homozygous for long alleles (l) of an insertion/deletion polymorphism in the promoter region of the serotonin transporter (5-HTTPR) had elevated rates of aggressive behavior.

OBJECTIVE

To examine whether the 5-HTTPR ll genotype confers an increased risk of AD+P, and of the combined AD+P/aggressive phenotype.

METHODS

The 5-HTTPR genotype was determined in 332 subjects diagnosed with possible or probable AD. All subjects received structured psychiatric assessments and were categorized with regard to their history of aggressive behaviors and psychotic symptoms.

RESULTS

Consistent with other reports, AD+P was associated with a significant increased risk for aggressive behavior. AD+P and aggression were both significantly associated with 5-HTTPR ll genotype and with an increased l allele frequency. Subjects with the combined behavioral phenotype (AD+P and aggressive behavior) had the highest rate of ll genotype and highest l allele frequency.

CONCLUSION

The 5-HTTPR l allele appears to confer risk for the combined AD+P/aggressive phenotype. Confirmation of this association in a similar behaviorally well-characterized independent sample is needed.

Hydrazinonaphthalene and azonaphthalene thrombopoietin mimics are nonpeptidyl promoters of megakaryocytopoiesis

High-throughput screening for the induction of a luciferase reporter gene in a thrombopoietin (TPO)-responsive cell line resulted in the identification of 4-diazo-3-hydroxy-1-naphthalenesulfonic acids as TPO mimics. Modification of the core structure and adjustment of unwanted functionality resulted in the development of (5-oxo-1,5-dihydropyrazol-4-ylidene)hydrazines which exhibited efficacies equivalent to those of TPO in several cell-based assays designed to measure thrombopoietic activity. Furthermore, these compounds elicited biochemical responses in TPO-receptor-expressing cells similar to those in TPO itself, including kinase activation and protein phosphorylation. Potencies for the best compounds were high for such low molecular weight compounds (MW < 500) with EC(50) values in the region of 1-20 nM.

The 5-HTTPR*S/*L polymorphism and aggressive behavior in Alzheimer disease

BACKGROUND

Aggressive behavior in Alzheimer disease (AD) has been linked to dysfunction of serotonin neurotransmission. Homozygosity for the long variant (*L) of an identified biallelic polymorphism of the serotonin transporter promoter region (5-HTTPR) is associated with increased expression of the transporter protein and increased speed of response to serotonin reuptake inhibitor treatment.

OBJECTIVE

To determine whether the *L/*L genotype and the *L allele are associated with an increased risk of aggressive symptoms in patients with AD.

DESIGN

Case-control study.

SETTING

University hospital geriatric psychiatry inpatient program and Alzheimer disease research center.

SUBJECTS

Fifty-eight patients with AD with a history of aggressive behavior and 79 never-aggressive patients with AD with comparable severity of cognitive impairment.

MAIN OUTCOME MEASURES

The 5-HTTPR genotype and allele frequency.

RESULTS

The *L/*L genotype was significantly associated with aggression in patients with AD (odds ratio, 2.8; 95% confidence interval, 1.2-6.5). Similar results were obtained for *L allele frequency.

CONCLUSION

The 5-HTTPR*L allele and *L/*L genotype may predispose patients with AD to develop aggressive behavior.

A double-blind randomized comparison of nortriptyline plus perphenazine versus nortriptyline plus placebo in the treatment of psychotic depression in late life

OBJECTIVE

To conduct the first randomized study comparing the efficacy of an antidepressant alone versus an antidepressant plus a neuroleptic in the treatment of late-life psychotic depression.

METHOD

The efficacy of nortriptyline plus placebo versus nortriptyline plus perphenazine was compared in 36 patients aged 50 years or older presenting with a major depressive episode with psychotic features (DSM-III-R criteria). Patients were started openly on nortriptyline treatment titrated to therapeutic levels. They were then randomly assigned under double-blind conditions to addition of perphenazine or placebo. Outcomes were compared in the 2 treatment groups using measures including the Hamilton Rating Scale for Depression (HAM-D) and the Brief Psychiatric Rating Scale (BPRS); side effects were assessed with the Geriatric Movement Disorder Assessment.

RESULTS

Both treatments were well tolerated. Of the 36 randomly assigned patients, 2 (1 in each group) dropped out due to treatment-related adverse effects. Four additional patients dropped out for administrative reasons. Thirty patients received nortriptyline for at least 4 weeks combined with either perphenazine (N = 14) or placebo (N = 16) for at least 2 weeks (median = 9 weeks). There was no significant difference between the completers in the 2 treatment groups when comparing their scores on the HAM-D, the BPRS, its psychoticism subscale, or any side effects measure. Rates of response (defined as resolution of both depression and psychosis) did not differ significantly in the 2 groups (nortriptyline-plus-perphenazine group, 50% vs. nortriptyline-plus-placebo group, 44%).

CONCLUSION

When treating older patients with psychotic depression, the addition of a moderate dose of a traditional neuroleptic to a tricyclic antidepressant was well tolerated but did not improve efficacy. This finding supports existing data suggesting that the pathophysiology (and thus the required treatment) of psychotic depression may be different early and late in life.

Hidden images in halftone pictures

A method of concealing an image in a different halftone image is proposed. Continuous-tone levels of the visible images are represented by the area of the halftone dots. However, the hidden image is encoded by the dots' positions inside their cells. Only a spatial correlator with a unique filter function can reveal the hidden image from the halftone picture. The technique and its robustness to noise and distortions are demonstrated.

Objective laparoscopic skills assessments of surgical residents using Hidden Markov Models based on haptic information and tool/tissue interactions

Laparoscopic surgical skills evaluation of surgery residents is usually a subjective process, carried out in the operating room by senior surgeons. By its nature, this process is performed using fuzzy criteria. The objective of the current study was to develop and assess an objective laparoscopic surgical skill scale using Hidden Markov Models (HMM) based on haptic information, tool/tissue interactions and visual task decomposition.

METHODS

Eight subjects (six surgical trainees: first year surgical residents 2 x R1, third year surgical residents 2 x R3 fifth year surgical residents 2 x R5; and two expert laparoscopic surgeons: 2 x ES) performed laparoscopic cholecystectomy following a specific 7 steps protocol on a pig. An instrumented laparoscopic grasper equipped with a three-axis force/torque sensor located at the proximal end with an additional force sensor located on the handle, was used to measure the forces and torques. The hand/tool interface force/torque data was synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis was used to define 14 different types of tool/tissue interactions, each one associated with unique force/torque (F/T) signatures. HMMs were developed for each subject representing the surgical skills by defining the various tool/tissue interactions as states and the associated F/T signatures as observations. The statistical distance between the HMMs representing residents at different levels of their training and the HMMs of expert surgeons were calculated in order to generate a learning curve of selected steps during laparoscopic cholecystectomy.

RESULTS

Comparison of HMM's between groups showed significant differences between all skill levels, supporting the objective definition of a learning curve. The major differences between skill levels were: (i) magnitudes of F/T applied (ii) types of tool/tissue interactions used and the transition between them and (iii) time intervals spent in each tool/tissue interaction and the overall completion time. The objective HMM analysis showed that the greatest difference in performance was between R1 and R3 groups and then decreased as the level of expertise increased, suggesting that significant laparoscopic surgical capability develops between the first and the third years of their residency training. The power of the methodology using HMM for objective surgical skill assessment arises from the fact that it compiles enormous amount of data regarding different aspects of surgical skill into a very compact model that can be translated into a single number representing the distance from expert performance. Moreover, the methodology is not limited to in-vivo condition as demonstrated in the current study. It can be extended to other modalities such as measuring performance in surgical simulators and robotic systems.

MEDNET: a medical simulation network grand challenge

The need to improve war-fighter training led to significant advancements in simulator technology. Now, simulator technology is ready to be applied to a new challenge: an evolutionary approach to training military medical personnel that will result in improved combat casualty care. With the exception of the introduction of helicopter evacuation support during the Korean War, changes in combat casualty care have not significantly altered the percentage of wounded soldiers lost in combat since World War II. The introduction of battlefield simulator training has improved strategic planning and combat readiness. It is time to apply these same tools to improve medical planning, military medical readiness and execution of casualty care.

Computer-generated holograms of three-dimensional realistic objects recorded without wave interference

We propose a method of synthesizing computer-generated holograms of real-life three-dimensional (3-D) objects. An ordinary digital camera illuminated by incoherent white light records several projections of the 3-D object from different points of view. The recorded data are numerically processed to yield a two-dimensional complex function, which is then encoded as a computer-generated hologram. When this hologram is illuminated by a plane wave, a 3-D real image of the object is reconstructed.

Markov modeling of minimally invasive surgery based on tool/tissue interaction and force/torque signatures for evaluating surgical skills

The best method of training for laparoscopic surgical skills is controversial. Some advocate observation in the operating room, while others promote animal and simulated models or a combination of surgery-related tasks. A crucial process in surgical education is to evaluate the level of surgical skills. For laparoscopic surgery, skill evaluation is traditionally performed subjectively by experts grading a video of a procedure performed by a student. By its nature, this process uses fuzzy criteria. The objective of the current study was to develop and assess a skill scale using Markov models (MMs). Ten surgeons [five novice surgeons (NS); five expert surgeons (ES)] performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper equipped with a three-axis force/torque (F/T) sensor was used to measure the forces/torques at the hand/tool interface synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis and a vector quantization algorithm, allowed to define F/T signatures associated with 14 different types of tool/tissue interactions. The magnitude of F/T applied by NS and ES were significantly different (p < 0.05) and varied based on the task being performed. High F/T magnitudes were applied by NS compared with ES while performing tissue manipulation and vise versa in tasks involved tissue dissection. From each step of the surgical procedures, two MMs were developed representing the performance of three surgeons out of the five in the ES and NS groups. The data obtained by the remaining two surgeons in each group were used for evaluating the performance scale. The final result was a surgical performance index which represented a ratio of statistical similarity between the examined surgeon's MM and the MM of NS and ES. The difference between the performance index value, for a surgeon under study, and the NS/ES boundary, indicated the level of expertise in the surgeon's own group. Using this index, 87.5% of the surgical procedures were correctly classified into the NS and ES groups. The 12.5% of the procedures that were misclassified were performed by the ES and classified as NS. However in these cases the performance index values were very close to the NS/ES boundary. Preliminary data suggest that a performance index based on MM and F/T signatures provides an objective means of distinguishing NS from ES. In addition, this methodology can be further applied to evaluate haptic virtual reality surgical simulators for improving realism in surgical education.

Control-relevant intervention in the treatment of minor and major depression in a long-term care facility

The authors assessed the effect of a control-relevant psychosocial intervention in 31 nursing home residents with either major depressive episode or minor depression. An initial group of 22 residents were randomized to either active treatment or waiting list. Four of 11 residents randomized to active treatment were deemed Responders, compared with 0 of 11 on the waiting list (P < 0.05). Of the total of 31 residents who participated in the intervention, 14 (45%) were deemed Responders during the intervention period. For these Responders, the Hamilton Rating Scale for Depression (Ham-D) and Geriatric Depression Scale scores improved significantly during the intervention. The improvement in the Ham-D was not sustained 2 months after intervention was terminated. These findings suggest that a psychosocial intervention enhancing socialization according to each resident's choice had a positive therapeutic impact on almost half of the nursing home residents with major or minor depression. However this effect could not be sustained by the residents without the support of the structured program.

Impulsivity

Disorders characterized by impulsivity include disorders of impulse control (intermittent explosive disorder, pyromania, kleptomania, pathological gambling and trichotillomania), paraphilias, sexual impulsions and sexual addictions and impulsive aggression personality disorders (borderline, antisocial, histrionic and narcissistic personality disorders). Impulsivity has a substantial impact on both individuals and society. Impulse control disorders may be conceptualized as a subset of the obsessive-compulsive spectrum. In this article, we examine the genetic and neurobiological aetiology of these disorders and possible treatment options. The link between serotonergic dysfunction and the pathophysiology of impulsivity is discussed, and studies that examine the efficacy of various selective serotonin reuptake inhibitors and other alternatives in the treatment of impulsive disorders such as pathological gambling, sexual addictions and borderline personality disorder are presented.

A labor perspective of workplace violence prevention. Identifying research needs

BACKGROUND

During the past decade, labor unions have contributed to efforts to increase awareness of the importance of workplace violence as an occupational hazard. Research by the National Institute for Occupational Safety and Health and the U.S. Department of Justice have bolstered these efforts. This research revealed that workplace violence is the second leading cause of traumatic-injury death on the job for men, the leading cause of traumatic-injury death on the job for women, and accounts for some 2 million nonfatal injuries each year in the United States.

LABOR PERSPECTIVE

Ten years ago, the debate focused on whether workplace violence is an occupational hazard or strictly a police and criminal justice issue. Labor unions have joined with occupational safety and health professionals in recognizing that workplace violence is a serious occupational hazard that is often predictable and preventable. They have advocated that employers establish multidimensional violence-prevention programs.

CONCLUSION

Although the nature of workplace violence varies from industry to industry, implementation of the federal Occupational Safety and Health Administration (OSHA) Violence Prevention Guidelines for Health Care and Social Service Workers and for Late-Night Retail Establishments is a high priority to unions in the affected industries. Labor wants employers to invest in protecting workers from violence through voluntary programs and state legislation, and it supports the promulgation of a mandatory federal OSHA standard. To that end, intervention research can play a key role in demonstrating effective, technically and economically feasible prevention strategies

Effects of geared motor characteristics on tactile perception of tissue stiffness

Endoscopic haptic surgical devices have shown promise in addressing the loss of tactile sensation associated with minimally invasive surgery. However, these devices must be capable of generating forces and torques similar to those applied on the tissue with a standard endoscopic tool. Geared motors are a possible solution for actuation; however, they possess mechanical characteristics that could potentially interfere with tactile perception of tissue qualities. The aim of the current research was to determine how the characteristics of a geared motor suitable for a haptic surgical device affect a user's perception of stiffness. The experiment involved six blindfolded subjects who were asked to discriminate the stiffness of six distinct silicone rubber samples whose mechanical properties are similar to those of soft tissue. Using a novel testing device whose dimensions approximated those of an endoscopic grasper, each subject palpated 30 permutations of sample pairs for each of three types of mechanical loads; the motor (friction and inertia), a flywheel (with the same inertia as motor), and a control (no significant mechanical interference). One factor ANOVA of the error scores and palpation time showed that no significant difference existed among error scores, but mean palpation time for the control was significantly less than for the other two methods. These results indicated that the mechanical characteristics of a geared motor chosen for application in a haptic surgical device did not interfere with the subjects' perception of the silicone samples' stiffness, but these characteristics may significantly affect the energy expenditure and time required for tissue palpation. Therefore, before geared motors can be considered for use in haptic surgical devices, consideration should be given to factors such as palpation speed and fatigue.

Therapeutic radiation and the neurosurgeon

For nearly a century, neurosurgeons have been involved in the use of therapeutic radiation. Long before there was a separate discipline of radiology or radiation therapy, pioneers such as Cushing and Frasier explored the effects of X-rays and radium on patients with brain tumors and arteriovenous malformations. This interest was never completely abandoned and was again pursued with vigor with the emergence of image-guided sterotaxy for use in intracranial brachytherapy and radiosurgery. Neurosurgeons have been and will remain at the forefront of these and other emerging techniques.

Three-dimensional optical correlator with general complex filters

A new type of electro-optical three-dimensional (3-D) correlator is proposed and demonstrated. A 3-D object scene, observed by multiple cameras from several points of view, is correlated with a 3-D complex computer-generated function. This correlator is a hybridization of the joint transform and the VanderLugt correlators, and, as such, it allows correlations to be made between 3-D real-world objects and 3-D general complex functions. Experimental results are presented.

Nitric acid trihydrate (NAT) in polar stratospheric clouds

A comprehensive investigation of polar stratospheric clouds was performed on 25 January 2000 with instruments onboard a balloon gondola flown from Kiruna, Sweden. Cloud layers were repeatedly encountered at altitudes between 20 and 24 kilometers over a wide range of atmospheric temperatures (185 to 197 kelvin). Particle composition analysis showed that a large fraction of the cloud layers was composed of nitric acid trihydrate (NAT) particles, containing water and nitric acid at a molar ratio of 3:1; this confirmed that these long-sought solid crystals exist well above ice formation temperatures. The presence of NAT particles enhances the potential for chlorine activation with subsequent ozone destruction in polar regions, particularly in early and late winter.

Security and encryption optical systems based on a correlator with significant output images

An improved optical security system based on two phase-only computer-generated masks is proposed. The two transparencies are placed together in a 4f correlator so that a known output image is received. In addition to simple verification, our security system is capable of identifying the type of input mask according to the corresponding output image it generates. The two phase masks are designed with an iterative optimization algorithm with constraints in the input and the output domains. A simulation is presented with the resultant images formed by the two phase-only elements. Various mask combinations are compared to show that a combination is unique and cannot be duplicated. This uniqueness is an advantage in security systems.

Hidden Markov models of minimally invasive surgery

A crucial process in surgical education is to evaluate the level of surgical skills. For laparoscopic surgery, skill evaluation is traditionally preformed subjectively by experts grading a video of a procedure performed by a student. By its nature, this process is preformed using fuzzy criteria. The objective of the current study was to develop and assess a skill scale using Discrete Hidden Markov Models (DHMM). Ten surgeons (5 Novice Surgeons--NS; 5 Expert Surgeons--ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper equipped with a three-axis force/torque sensor was used to measure the forces/torques at the hand/tool interface synchronized with a video of the tool operative maneuvers. A synthesis of frame-by-frame video analysis and a vector quantization algorithm, defined force/torque signatures for 14 types of tool/tissue interactions. From each step of the surgical procedures, two DHMM were developed representing the performance of 3 surgeons randomly selected from the 5 in the ES and NS groups. The data obtained by the remaining 2 surgeons in each group were used for evaluating the performance scale. The final result was a surgical performance index which represented a ratio of statistical similarity between the examined surgeon's DHMM and the DHMM of NS and ES. The difference between the performance index value, for a surgeon under study, and the NS/ES boundary, was considered to indicate the level of expertise in the surgeon's own group. Using this index, 87.5% of the surgical procedures were correctly classified into the NS and ES groups. The 12.5% of the procedures that were misclassified were preformed by the ES and classified as NS. However, in these cases the performance index values were very close to the NS/ES boundary. Preliminary data suggest that a performance index based on DHMM and force/torque signatures provides an objective means of distinguishing NS from ES. In addition this methodology can be further applied to evaluate haptic virtual reality surgical simulators for improving realism in surgical education.

Skills evaluation in minimally invasive surgery using force/torque signatures

BACKGROUND

One of the more difficult tasks in surgical education is to teach the optimal application of instrument forces and torques necessary to facilitate the conduct of an operation. For laparoscopic surgery, this type of training has traditionally taken place in the operating room, reducing operating room efficiency and potentially affecting the safe conduct of the operation. The objective of the current study was to measure and compare forces and torques (F/T) applied at the tool/hand interface generated during laparoscopic surgery by novice (NS) and experienced (ES) surgeons using an instrumented laparoscopic grasper and to use this data for evaluating the skill level.

METHODS

Ten surgeons (five-NS, five-ES) performed a cholecystectomy and Nissen fundoplication in a porcine model. An instrumented laparoscopic grasper with interchangeable standard surgical tips equipped with a three-axis F/T sensor located at the proximal end of the grasper tube was used to measure the F/T at the hand/tool interface. In addition, one axis force sensor located at the grasper's handle was used to measure the grasping force. F/T data synchronized with visual view of the tool operative maneuvers were collected simultaneously via a novel graphic user interface incorporated picture-in-picture video technology. Subsequent frame-by-frame video analysis of the operation allowed a definition of states associated with different tool/tissue interactions within each step of the operation. F/T measured within each state were further analyzed using vector quantization (VQ). The VQ analysis defines characteristic sets of F/T in the database that were defined as F/T signature.

RESULTS

The magnitude of F/T applied by NS and ES were significantly different (p < 0.05) and varied based on the task being performed. Higher F/T magnitudes were applied by NS than by ES when performing tissue manipulation, whereas lower F/T magnitudes were applied by NS than by ES during tissue dissection. Furthermore, the time to complete the surgical procedure was longer for NS by a factor of 1.5-4.8 when compared to the time for ES. State analysis suggests that most of this time is consumed in an [idle] state, in which movements of the surgeon make no tissue contact.

CONCLUSIONS

Preliminary data suggest that F/T magnitudes associated with the tool/tissue interactions provide an objective means of distinguishing novices from skilled surgeons. Clinical F/T analysis using the proposed technology and methodology may be helpful in training, developing surgical simulators, and measuring technical proficiency during laparoscopic surgery.

Longitudinal spatial coherence applied for surface profilometry

A method of optical coherence profilometry, believed to be new, is demonstrated. This method is based on the spatial, rather than the temporal, coherence phenomenon. Therefore the proposed interferometric system is illuminated by a quasi-monochromatic spatial incoherent source instead of a broadband light source. The surface profile is measured by means of shifting the spatial degree of coherence gradually along its longitudinal axis while keeping the optical path difference between the measured surface and a reference plane constant. Experimental proof of the new principle is presented.

Comparison of Cryptosporidium parvum viability and infectivity assays following ozone treatment of oocysts

Several in vitro surrogates have been developed as convenient, user-friendly alternatives to mouse infectivity assays for determining the viability of Cryptosporidium parvum oocysts. Such viability assays have been used increasingly to determine oocyst inactivation following treatment with chemical, physical, or environmental stresses. Defining the relationship between in vitro viability assays and oocyst infectivity in susceptible hosts is critical for determining the significance of existing oocyst inactivation data for these in vitro assays and their suitability in future studies. In this study, four viability assays were compared with mouse infectivity assays, using neonatal CD-1 mice. Studies were conducted in the United States and United Kingdom using fresh (<1 month) or environmentally aged (3 months at 4 degrees C) oocysts, which were partially inactivated by ozonation before viability and/or infectivity analyses. High levels of variability were noted within and between the viability and infectivity assays in the U.S. and United Kingdom studies despite rigorous control over oocyst conditions and disinfection experiments. Based on the viability analysis of oocyst subsamples from each ozonation experiment, SYTO-59 assays demonstrated minimal change in oocyst viability, whereas 4',6'-diamidino-2-phenylindole-propidium iodide assays, in vitro excystation, and SYTO-9 assays showed a marginal reduction in oocyst viability. In contrast, the neonatal mouse infectivity assay demonstrated significantly higher levels of oocyst inactivation in the U.S. and United Kingdom experiments. These comparisons illustrate that four in vitro viability assays cannot be used to reliably predict oocyst inactivation following treatment with low levels of ozone. Neonatal mouse infectivity assays should continue to be regarded as a "gold standard" until suitable alternative viability surrogates are identified for disinfection studies.

Pharmaceutical intervention in the JAK/STAT signaling pathway

Many cytokines exert their effect via the JAK/STAT signal transduction pathway. Due to the medical relevance of many of these cytokines, they are being exploited, either directly, or through antagonists, as therapeutics for a variety of serious diseases. Currently, these therapeutics consist almost entirely of protein products, with all of their attendant drawbacks. Delineation of the signaling mechanisms for the cytokines, however, has allowed the design and implementation of a variety of cell-based and biochemical screens for small molecule mimics or antagonists of these cytokines. Several successful assays will be described along with the advantages of each type of assay. Use of assays of this type should make it possible to discover numerous small molecule cytokine modulators with significant utility in the clinic. Oncogene (2000).

Weight loss is correlated with an improved lipoprotein profile in obese postmenopausal women

BACKGROUND

Changes in plasma lipid and lipoprotein distributions that occur after menopause increase the risk of cardiovascular disease in women, especially in those who are overweight.

OBJECTIVE

The purpose of this study was to evaluate the impact of a nine-month weight reduction program on plasma lipids, dietary intake and abdominal fat obesity.

DESIGN

A partial crossover design was used to study a weight loss treatment consisting of Phentermine hydrochloride (Fastin, SmithKline Beecham Pharmaceuticals, Philadelphia, PA) therapy plus a low energy diet (5040 kJ/d). Forty-seven obese, postmenopausal Caucasian women (BMI of 30-38 kg/m2) were randomized into two groups, both of which received drug and diet treatment over six months. However, Group I started the intervention program three months later than Group II. Plasma total, HDL and LDL cholesterol and triacylglycerol were measured, body composition was assessed by anthropometry and dual energy x-ray absorptiometry, and food frequency records were collected at four timepoints.

RESULTS

Over nine months, women in Group II reduced body weight (14.4%), lowered plasma concentrations of LDL cholesterol (14% to 26%) and triacylglycerol (15%) and raised plasma HDL cholesterol concentration (15%). These plasma lipid changes decreased the total cholesterol/HDL cholesterol ratio from 4.3 to 3.2. All subjects decreased abdominal fat measurements and energy and cholesterol intakes, as well as percentage of energy derived from total and saturated fat during the study. Most subjects also increased dietary fiber consumption.

CONCLUSION

Both weight loss and diet modifications are associated with an improved plasma lipid profile in obese postmenopausal women.

Pharmacologic profile of perphenazine's metabolites

The authors have previously reported that in elderly patients treated with low doses of perphenazine, few extrapyramidal symptoms (EPS) developed in those who were not poor CYP2D6 metabolizers. The authors hypothesized that this atypical side effect profile is due to perphenazine's principal metabolite, n-dealkylperphenazine (DAPZ), which is usually present in vivo at concentrations 1.5 to 2 times that of the parent drug. Perphenazine, DAPZ, and 7-hydroxyperphenazine affinities were examined in vitro by competition-binding analysis to isolated human receptors expressed in transfected cell lines. Perphenazine and metabolite effects were examined in vivo in 54 older patients who were treated with perphenazine, at a target dose of 0.1 mg/kg, for 10 to 17 days. Drug concentrations were determined by high-performance liquid chromatography with electrochemical detection. In in vitro binding studies, DAPZ demonstrated a higher affinity for serotonin-2A receptors than for dopamine-2 receptors to an extent comparable to that of some atypical neuroleptic agents. In contrast, perphenazine and 7-hydroxyperphenazine demonstrated a higher affinity for dopamine-2 receptors than for serotonin-2A receptors. The mean +/- SD concentrations in the 54 subjects were the following: perphenazine, 1.5 +/- 1.4 ng/mL; DAPZ, 2.0 +/-1.6 ng/mL; and 7-hydroxyperphenazine, 0.8 +/- 1.9 ng/mL. The mean +/- SD quotient for the DAPZ/perphenazine concentration was 1.7 +/- 1.1 and for the 7-hydroxyperphenazine/perphenazine was 0.54 +/-1.6. EPS onset was not correlated with the perphenazine concentration, the metabolite concentrations, the DAPZ/perphenazine quotient, or the 7-hydroxyperphenazine/perphenazine quotient. Despite a moderately atypical receptor-binding profile, DAPZ does not seem to moderate perphenazine effects in vivo in older patients. This outcome likely reflects the low potency of DAPZ for dopamine-2 and serotonin-2A receptors relative to the potency of perphenazine for these receptors. Further exploration of atypical properties of DAPZ should include de novo administration of this metabolite in animal models.

Three-dimensional pattern recognition with a single two-dimensional synthetic reference function

A novel, to our knowledge, method of distortion-invariant three-dimensional (3-D) pattern recognition is proposed. A single two-dimensional synthetic discriminant function is employed as a reference function in the 3-D correlator. Thus the proposed system is able to identify and locate any true-class object in the 3-D scene. Preliminary simulation and experimental results are presented.

Sertraline in the treatment of minor depression in nursing home residents: a pilot study

'Minor' depression affects up to 50% of residents in long-term care facilities and is associated with considerable discomfort, disability and risk of morbidity. Despite the prevalence of this problem, few studies addressing the treatment of these patients have been conducted. In an open clinical trial, 12 nursing home residents who met the DSM-IV description for minor depressive disorder were treated with sertraline for 6 weeks. Adverse effects and clinical response were monitored. All residents tolerated their medication without any significant side-effects. At the completion of the study, the Hamilton Depression Rating Scale and Global Assessment Scale change scores both indicated significant improvement and 75% of the residents met criteria for 'remission'. This preliminary study provides evidence that nursing home residents with minor depression tolerated treatment with sertraline and improved clinically.

Determination of emamectin benzoate in medicated fish feed

A method was developed to quantitate emamectin benzoate in fish feed at levels between 5 and 15 ppm. The active ingredient is extracted from 20 g medicated feed into aqueous-methanolic solvent by overnight shaking. A solid-phase extraction procedure using a 2 g C18 cartridge is then used to concentrate the active residue and remove interfering matrix components. The extracted drug and internal standard are eluted from the cartridge, evaporated to dryness, and reconstituted in methanol. A control feed sample and fortified control working standard are simultaneously prepared. Remaining interferences and sample analysis are further separated on a gradient liquid chromatographic system. Recovery of emamectin benzoate from fortified feeds ranged from 97 to 100%, with a coefficient of variation (CV) of 1.2%. Determination of emamectin benzoate in medicated feeds resulted in CVs ranging from 2.3 to 4.2% and recoveries of 88 to 98% of label claim.

Research potential of a unique xenograft model of human proliferative breast disease

A workshop on the 'Research potential of a unique xenograft model of human proliferative breast disease' was held at the Karmanos Cancer Institute, Wayne State University, Detroit, Michigan, in November of 1998. The accumulated information and current experimental findings on the MCF10AT model of preneoplastic, proliferative breast disease were reviewed. Discussions focused on the relevance of the model to clinical breast cancer and on the most profitable lines of further research to strengthen its utility.

Surgeon-tool force/torque signatures--evaluation of surgical skills in minimally invasive surgery

The best method of training for laparoscopic surgical skills is controversial. Some advocate observation in the operating room, while others promote animal and simulated models or a combination of surgical related tasks. The mode of proficiency evaluation common to all of these methods has been subjective evaluation by a skilled surgeon. In order to define an objective means of evaluating performance, an instrumented laparoscopic grasper was developed measuring the force/torque at the surgeon hand/tool interface. The measured database demonstrated substantial differences between experienced and novice surgeon groups. Analyzing forces and torques combined with the state transition during surgical procedures allows an objective measurement of skill in MIS. Teaching the novice surgeon to limit excessive loads and improve movement efficiency during surgical procedures can potentially result in less injury to soft tissues and less wasted time during laparoscopic surgery. Moreover the force/torque database measured in this study may be used for developing realistic virtual reality simulators and optimization of medical robots performance.