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Biomedical subjects

R C Merrell

Publications and source records attributed to R C Merrell.

At least 19 recordsLinked to original sources
PubMed2006

Skill performance in open videoscopic surgery.

INTRODUCTION: Application of minimally invasive surgery represents the future of modern surgical care. Previous studies by our group provided a novel way for viewing open surgery using a rigid endoscope attached to charged coupled device (CCD) camera in proximity to the surgical field using a robotic arm (AESOP) and a stabilizing fulcrum (Alpha port). MATERIALS AND METHODS: This study is a follow-up to investigate the technical feasibility, advantages, and disadvantages of relying only on video images displayed on standard monitors in performing open surgical procedures instead of direct binocular eye vision. This study used two surgeons as participants with training in basic surgical skill and previous experience in performing an intestinal anastomosis in an ordinary fashion. The standard task consisted of anastomosing porcine intestine in two layers with digital viewing of the operative field. A total of 40 anastomoses (20 by each surgeon) were compared with 10 control performances using direct vision of the field. RESULTS: All the resulting anastomoses were accurate, well coapted, and fully patent with no leakage. Time for task performance was approximately twice as long (p < 0.05) with videoscopic vision as with direct vision. DISCUSSION: These findings suggest it is technically feasible to conduct open surgeries with visualization of the open surgical field limited to video display on standard monitors.

Anastomosis, Surgical↗
PubMed2005

Telementoring versus on-site mentoring in virtual reality-based surgical training.

BACKGROUND: Telementoring can be an adjunct to surgical training using virtual reality surgical simulation. Telementoring is hypothesized to be as effective as a local mentor for surgical skills training. METHODS: In this study, 20 Romanian medical students trained using a virtual reality surgical simulator (LapSim) with a telementor or local mentor. All the students watched an instructional module at the beginning of the exercise. The telementor, in the United States, interacted by videoconferencing. Before and after training sessions, tool path length and time for task completion were measured. RESULTS: Instructional media and training with mentoring resulted in similar levels of performance between locally mentored and telementored groups. Right- and left-hand path length and time decreased significantly within each group from the initial to the final evaluation (p < 0.05) for most tasks (grasping, cutting, suturing). No significant difference was achieved for clip-applying. CONCLUSIONS: Integration of instructional media with telementoring can be as effective for the development of surgical skills as local mentoring.

Education, Medical↗
PubMed2003

A pilot telemedicine project in the Privolzhsky District, Russia.

The geography of Russia and the complex structure of the Russian health-care system make telemedicine systems especially appropriate. The telemedicine project described here deploys a telemedicine system in Nizhny Novgorod with further integration into the Privolzhsky District telemedicine network. It started with the creation of a telemedicine center with high-speed dedicated communication links to various medical institutions in Moscow, interregional telemedicine centers, and several district hospitals in rural areas of the Privolzhsky district. In addition to this specialized network, training by telemedicine specialists from the Space Biomedical Center at Moscow State University was provided along with teleconsultations with specialists from the most advanced medical institutions in Moscow. Consultations were carried out via the interregional telemedicine center on a contractual basis. The regional telemedicine network linked nearly 78 medical sites. This system provided approximately 500 teleconsultations and 100 educational sessions within the past 3 years.

Pilot Projects↗
PubMed2002

Tele-affiliation in medical education: experience from the international program at Yale Office of Telemedicine.

OBJECTIVES: Telemedicine is developed in response to the needs of users that results in a more viable model. Yale has developed a process called tele-affiliation to combine services that are customized to the international client's needs. METHODS: Several defined steps compose the tele-affiliation process. The Yale-Greece telemedicine program is used as an illustration of this process. Some of the programs developed in response to Greek needs include breast cancer clinics, women's health clinics and tele-homecare monitoring for post-operative and chronically ill patients. RESULTS: Tele-affiliation creates on infrastructure that has the potential to change the method of health care delivery. By using the infrastructure created by the tele-affiliation process, templates for disease management, as well as health promotion and education can be delivered to a global audience. CONCLUSIONS: A tele-affiliation education environment has been developed and tested between Yale University School of Medicine and Greece resulting in an improved infrastructure for health education and management.

Breast Neoplasms↗
PubMed2001

Association of p53, p16, and vascular endothelial growth factor protein expressions with the prognosis and metastasis of gallbladder cancer.

BACKGROUND: Tumor suppressor genes were studied in gallbladder disease including cancer for correlation. VEGF (vascular endothelial growth factor) expression was assessed against Nevin staging and metastasis of gallbladder carcinoma. The importance of p53, p16, and VEGF in gallbladder cancer was estimated. STUDY DESIGN: Twenty-four gallbladder carcinomas, 20 gallbladder adenomas, and 18 chronic cholecystitis specimens were immunohistochemically and histopathologically investigated for the relation of p53, p16, and VEGF to Nevin staging and pathologic grading. RESULTS: The expression rate of abnormal p53 in gallbladder carcinomas was significantly higher than that in gallbladder adenoma and chronic cholecystitis (p = 0.003, p = 0.014). The expression rate of abnormal p53 in Nevin staging S1, S2, S3 gallbladder carcinoma was significantly higher than that in S4, S5 (p = 0.01). Abnormal p16 was highest in carcinoma, next in adenoma, and lowest in chronic cholecystitis (p = 0.031, p = 0.017). Gallbladder carcinoma expressed VEGF far more often than adenoma or cholecystitis (p = 0.001); VEGF-positive rates were lower in S1, S2, S3 than S4, S5 by Nevin staging of gallbladder cancer (p = 0.044). CONCLUSION: Mutation of p53 and p16 genes might correlate with progression of of gallbladder carcinoma. Analysis of p53 and p16 can estimate the prognosis of gallbladder cancer. VEGF expression correlates with Nevin staging in gallbladder cancer.

Adenoma↗
PubMed2001

Laparoscopic telescope with alpha port and aesop to view open surgical procedures.

Laparoscopy has advanced surgery by allowing the surgeon to operate within a patient's abdominal and pelvic cavity with minimal trauma and scarring. The coupling of a video camera to the laparoscopic telescope has had the secondary effect of allowing others to view the surgical field either on color video monitors or by watching the video feed over the Internet at a remote location. These advancements have allowed better teaching and mentoring of operations. Open procedures can benefit from this technology as well but have suffered in the past from inadequate methods to depict the open surgical field. We used the Alpha Port and Aesop robot to position a sterile laparoscopic telescope near the surgical field to view open cholecystectomies performed on five pigs and to send the video feed over the Internet to remote physicians. Viewing the video on the monitor, the surgeons performed the operation in a comfortable ergonomic upright position. Both the surgeons and the remote physicians found the quality of the video to be excellent, and the remote physicians felt comfortable learning and mentoring surgical procedures using this technique.

Animals↗
PubMed2001

Wireless ECG monitoring by telephone.

The objective of this work was to study a wireless one channel limited (3-lead) home electrocardiogram (ECG) transmission system and ambulatory devices data transmission using telephone lines. ECG screenings were conducted in two groups. The first group consisted of construction workers examined at first aid stations at construction sites in Moscow, Russia. The second group was a selected set of patients admitted to a hospital in Tblisi, Republic of Georgia. All patients were on constant monitoring and follow-up after hospitalization. Patients themselves connected the ECG leads at home or with the help of paramedics at ambulatory stations. The ECG signals were transmitted to receiving stations where doctors interpreted them. Frequency modulation was used for ECG transmission over regular telephone lines. Of 231 readings in 74 patients--70 male and 4 female (age 21-56)--in the first group, 33 patients were abnormal. In the second group, 15 out of 165 readings in 8 patients--5 male and 3 female (age 31-70)--were abnormal. ECG screening can be significantly simplified and made widely acceptable at home and distant sites using wireless monitoring tools and telephone line transfer of the signal. This project has been implemented under the auspices of the International Telecommunication Union and the Russian Telemedicine Foundation.

Adult↗
PubMed2001

Impact of varying transmission bandwidth on image quality.

The objective of this paper is to determine the effect of varying transmission bandwidth on image quality in laparoscopic surgery. Surgeons located in remote operating rooms connected through a telemedicine link must be able to transmit medical images for interaction. Image clarity and color fidelity are of critical importance in telementoring laparoscopic procedures. The clarity of laparoscopic images was measured by assessing visual acuity using a video image of a Snellen eye chart obtained with standard diameter laparoscopes (2, 5, and 10 mm). The clarity of the local image was then compared to that of remote images transmitted using various bandwidths and connection protocols [33.6 Kbps POTS (IP), 128 Kbps ISDN, 384 Kbps ISDN, 10 Mbps LAN (IP)]. The laparoscopes were subsequently used to view standard color placards. These color images were sent via similar transmission bandwidths and connection protocols. The local and remote images of the color placards were compared to determine the effect of the transmission protocols on color fidelity. Use of laparoscopes of different diameter does not significantly affect image clarity or color fidelity as long as the laparoscopes are positioned at their optimal working distance. Decreasing transmission bandwidth does not significantly affect image clarity or color fidelity when sufficient time is allowed for the algorithms to redraw the remote image. Remote telementoring of laparoscopic procedures is feasible. However, low bandwidth connections require slow and/or temporarily stopped camera movements for the quality of the remote video image to approximate that of the local video image.

Color↗
PubMed2001

Real-time Internet connections: implications for surgical decision making in laparoscopy.

OBJECTIVE: To determine whether a low-bandwidth Internet connection can provide adequate image quality to support remote real-time surgical consultation. SUMMARY BACKGROUND DATA: Telemedicine has been used to support care at a distance through the use of expensive equipment and broadband communication links. In the past, the operating room has been an isolated environment that has been relatively inaccessible for real-time consultation. Recent technological advances have permitted videoconferencing over low-bandwidth, inexpensive Internet connections. If these connections are shown to provide adequate video quality for surgical applications, low-bandwidth telemedicine will open the operating room environment to remote real-time surgical consultation. METHODS: Surgeons performing a laparoscopic cholecystectomy in Ecuador or the Dominican Republic shared real-time laparoscopic images with a panel of surgeons at the parent university through a dial-up Internet account. The connection permitted video and audio teleconferencing to support real-time consultation as well as the transmission of real-time images and store-and-forward images for observation by the consultant panel. A total of six live consultations were analyzed. In addition, paired local and remote images were "grabbed" from the video feed during these laparoscopic cholecystectomies. Nine of these paired images were then placed into a Web-based tool designed to evaluate the effect of transmission on image quality. RESULTS: The authors showed for the first time the ability to identify critical anatomic structures in laparoscopy over a low-bandwidth connection via the Internet. The consultant panel of surgeons correctly remotely identified biliary and arterial anatomy during six laparoscopic cholecystectomies. Within the Web-based questionnaire, 15 surgeons could not blindly distinguish the quality of local and remote laparoscopic images. CONCLUSIONS: Low-bandwidth, Internet-based telemedicine is inexpensive, effective, and almost ubiquitous. Use of these inexpensive, portable technologies will allow sharing of surgical procedures and decisions regardless of location. Internet telemedicine consistently supported real-time intraoperative consultation in laparoscopic surgery. The implications are broad with respect to quality improvement and diffusion of knowledge as well as for basic consultation.

Cholecystectomy, Laparoscopic↗
PubMed2001

Wireless telemetry and Internet technologies for medical management: a Martian analogy.

BACKGROUND: The NASA Haughton-Mars Project Base Camp on Devon Island, Canada (approximately 75 degrees north) was the site for transmission of vital signs from two "terranauts" (individuals who acted as Earthbound astronauts) back to the United States in (artificially delayed) real-time. METHODS: The subjects became "physiologic ciphers" for status monitoring using readily available technologies that affordably captured and distributed vital signs to a variety of platforms. This study of nominal monitoring and simulated medical emergency used wireless technologies and the Internet. RESULTS: Basic vital signs and images can be sent using wireless topologies and completely automated functions. Due to the lightweight transport requirements, existing low data rate connections can easily handle the volume of traffic. CONCLUSIONS: Monitoring, the health of space travelers will be an important component for both low-Earth orbiting spacecraft and long-term missions to distant planets. However, terrestrial applications represent the primary application of such technologies because the home can be a remote and hazardous environment as well.

Aerospace Medicine↗
PubMed2001

The benefits of integrating Internet technology with standard communications for telemedicine in extreme environments.

The ability to continuously monitor the vital signs of a person can be beneficial especially if the environment is hazardous or a person simply has general health concerns. We wanted to ascertain if, by integrating the Internet, ubiquitous switching technologies and off-the-shelf tools, this "suite of services" could provide a topology to enable remote monitoring in extreme and remote locations. An evaluation of this approach was conducted at the base camp of Mount Everest in the spring of 1999. Three climbers were outfitted with wireless, wearable sensors and transmitters for 24 h as they ascended through the Khumbu Icefall toward Camp One. The physiologic data was forwarded to the receiving station at Base Camp where it was forwarded to the U.S. mainland. Two of the three devices delivered physiologic data 95%-100% of the time while the third unit operated at only 78%. According to the climbers, the devices were unobtrusive, however, any additional weight while climbing Everest must provide advantage.

Humans↗
PubMed2000

Effects of increased ambient pressure on colon cancer cell adhesion.

Forces such as strain modulate intestinal epithelial biology. Shear and pressure influence other cells. The effects of pressure on human colon cancer cells are poorly understood. Increasing ambient pressure for 30 min by 15 mm Hg over atmospheric stimulated adhesion to matrix proteins of four human colon cancer cell lines and primary cells from three human colon cancers, but not bovine aortic smooth-muscle cells. This effect was energy dependent and cation dependent (blocked by azide and chelation), accompanied by tyrosine phosphorylation of intracellular proteins including focal adhesion kinase, and blocked by tyrosine kinase inhibition (genistein, tyrphostin, and erbstatin) and a functional antibody to the beta1 integrin subunit. Although pressure stimulated adhesion even in a balanced salt solution, baseline and pressure-stimulated adhesion were each substantially diminished in the absence of serum. These data suggest that relatively low levels of increased pressure may stimulate malignant colonocyte adhesion by a cation-dependent beta1-integrin-mediated mechanism, perhaps via focal adhesion kinase-related tyrosine phosphorylation. In addition to elucidating another aspect of physical force regulation of colonocyte biology, these findings may be relevant to the effects of increased pressure engendered by colonic peristalsis, surgical manipulation, or laparoscopic surgery on colon cancer cell adhesion.

Animals↗
PubMed2000

Time-related changes in hemodynamic parameters and pressure-derived indices of left ventricular function in a porcine model of prolonged pneumoperitoneum.

BACKGROUND: Advanced laparoscopic procedures require prolonged pneumoperitoneum. Increased intra-abdominal pressure causes a number of hemodynamic changes including a drop in cardiac output, but it is unclear whether there is a direct effect on cardiac contractility. In this experimental study, we sought to determine whether there is a direct impact of pneumoperitoneum on cardiac contractility. We also examined the time-related changes taking place during the insufflation period. METHODS: Six young pigs were anesthetized and mechanically ventilated. Pneumoperitoneum was established by insufflating carbon dioxide to a pressure of 15 mmHg and maintained for a period of 180 min. Hemodynamic parameters including left ventricular dP/dT were invasively recorded every 15 min. All hemodynamic changes were statistically evaluated, and parameters were correlated with time. RESULTS: Cardiac output decreased with insufflation from a baseline of 3.37 +/- 0.34 lt/min and reached the lowest value at 165 min of pneumoperitoneum (2.86 +/- 0.30 l/min; p = 0.023). Systemic vascular resistance (SVR) significantly increased from 2236 +/- 227 dyne/s/cm(5) to a maximum of 3774 +/- 324 dyne/s/cm(5) (p = 0.005). Left ventricular dP/dT maximum did not change significantly with insufflation. The decrease in cardiac output strongly correlated with the increase in SVR (r = -0.949). Time of insufflation correlated with cardiac output (r = -0.762) and dP/dT maximum (r = -0.727). CONCLUSIONS: Pneumoperitoneum at 15 mmHg negatively affects cardiac output without significantly affecting cardiac contractility. A significant increase in SVR appears to be the driving event for the decreased cardiac output. Prolonged pneumoperitoneum may have an additional negative effect on hemodynamic parameters.

Animals↗
PubMed2000

Effectiveness of a CD-ROM multimedia tutorial in transferring cognitive knowledge essential for laparoscopic skill training.

BACKGROUND: Computer-assisted instruction (CAI) can benefit surgical education by improving efficiency, effectiveness, standardization, and access. This study compares knowledge gains for laparoscopic skill acquisition following a standardized tutorial delivered via CD-ROM versus live instructor. METHODS: A standardized tutorial was written and subsequently converted to multimedia CD-ROM format by its author (JR). During a laparoscopic development course, experienced US-trained surgeons (n = 52) participated in the tutorial delivered live by the author. The CD-ROM tutorial replaced the instructor for the following groups: (1) experienced US-trained surgeons (n = 27); (2) US-trained surgical residents (n = 59); and (3) Greek surgeons (n = 63). A 51-item knowledge test was administered before and after tutorial instruction. RESULTS: The mean increase in scores between pretest and posttest was significant (P <0.01) and of similar magnitude in each group, with nonsignificant posttest mean differences among US-trained groups. CONCLUSIONS: The CD-ROM tutorial effectively transfers cognitive information necessary for skill development. Distance learning modes of this tutorial program may be feasible.

CD-ROM↗
PubMed2000

A strategic vision for telemedicine and medical informatics in space flight.

This Workshop was designed to assist in the ongoing development and application of telemedicine and medical informatics to support extended space flight. Participants included specialists in telemedicine and medical/health informatics (terrestrial and space) medicine from NASA, federal agencies, academic centers, and research and development institutions located in the United States and several other countries. The participants in the working groups developed vision statements, requirements, approaches, and recommendations pertaining to developing and implementing a strategy pertaining to telemedicine and medical informatics. Although some of the conclusions and recommendations reflect ongoing work at NASA, others provided new insight and direction that may require a reprioritization of current NASA efforts in telemedicine and medical informatics. This, however, was the goal of the Workshop. NASA is seeking other perspectives and views from leading practitioners in the fields of telemedicine and medical informatics to invigorate an essential and high-priority component of the International Space Station and future extended exploration missions. Subsequent workshops will further define and refine the general findings and recommendations achieved here. NASA's ultimate aim is to build a sound telemedicine and medical informatics operational system to provide the best medical care available for astronauts going to Mars and beyond.

Aerospace Medicine↗
PubMed1998

Applications of telemedicine in the United States space program.

Since the beginning of human space flight, NASA has been placing humans in extreme and remote environments. There are many challenges in maintaining humans in outer space, including the provision of life-support systems, radiation shielding, and countermeasures for minimizing the effect of microgravity. Because astronauts are selected for their health, among other factors, disease and illness are minimized. However, it is still of great importance to have appropriate medical care systems in place to address illness and injury should they occur. With the exception of the Apollo program, exploration of space has been limited to missions that are within several hundred miles of the surface of the Earth. At the drawn of the 21st century and the new millennium, human exploration will be focused on operation of the International Space Station (ISS) and preparation for human missions to Mars. These missions will present inherent risks to human health, and, therefore, appropriate plans must be established to address these challenges and risks. Crews of long-duration missions must become more independent from ground controllers. New systems, protocols, and procedures are currently being perfected. Application of emerging technologies in information systems and telecommunications will be critical to inflight medical care. Application of these technologies through telemedicine will provide crew members access to information, noninvasive procedures for assessing health status, and guidance through the integration of sensors, holography, decision-support systems, and virtual environments. These technologies will also serve as a basis to enhance training and medical education. The design of medical care for space flight should lead to a redesign of the practice of medicine on Earth.

Computer Communication Networks↗