APOE-dependent PET patterns of brain activation in Alzheimer disease

Using H2(15)O PET, the authors imaged 13 patients with Alzheimer disease (AD) while performing a serial nonverbal recognition memory task. Patterns of brain activation differed as a function of APOE genotype: epsilon4 carriers exhibited lower activation in the left lingual gyrus and higher activation in left cuneus, precuneus, parahippocampal, and right precentral gyrus. The APOE genotype seems to play a role in cerebral physiologic activity even after onset of clinical manifestations of AD.

Advances in coupling a commercial total organic carbon analyser with an isotope ratio mass spectrometer to determine the isotopic signal of the total dissolved nitrogen pool

A new method has been developed to analyse 15N of the total dissolved nitrogen (TDN) pool. The method operates on a commercial total organic carbon (TOC) analyser coupled to an elemental analyser/isotope ratio mass spectrometer (EA-IRMS). Nitrogen compounds are combusted to nitric oxide (NO) and nitrogen dioxide (NO2) by high-temperature catalytic oxidation (HTCO), after which the NOx gas is transferred to an EA-IRMS for isotopic nitrogen analysis. The system is described, including five modifications of the system in order to overcome analytical problems. First, flow paths were modified to run both systems on helium as carrier gas, while complete sample oxidation was maintained. Secondly, the catalyst structure was adapted to allow high injection volumes at the given backpressures delivered by the EA system. Thirdly, we installed a Permapure dehumidification system as the standard Peltier element did not satisfy dehumidification requirements. Finally, we prevented the inflow of atmospheric nitrogen into the system. In a final stage, we are planning to automate the coupled system in order to run a continuous batch of up to 60 samples. We have obtained satisfactory results on the accuracy and precision of 180+/-1 per thousand potassium nitrate samples (IAEA, USGS-32). Running a batch of five samples resulted in a mean isotopic value of 178.8 per thousand with a standard deviation of 2.8 per thousand. Some important issues could not yet be addressed here, and will have to be evaluated once the system is running on a continuous base. However, the results appear promising and this system has the potential to become a method for TD15N analysis. An appropriate TD15N analysis method might open new challenges in aquatic and terrestrial ecosystem nitrogen studies, including a more comprehensive study of the dissolved organic nitrogen pool.

Evaluating the introduction of a pilot client attachment scheme in mental health nursing education

Client attachment (CA) allows student nurses to gain clinical experience through forming therapeutic attachments with individual clients, rather than through a series of location-based placements. This paper describes a pilot project that evaluated CA with pre-registration student mental health nurses. Using semi-structured interviews, the researchers identified the students', their supervisor's, and their clients' experiences of CA. Most participants agreed that students were able to learn relevant and appropriate clinical skills, and to consolidate experience-increasing motivation, autonomy, organizational skills, and confidence.

Live broadcast of laparoscopic surgery to handheld computers

BACKGROUND

Thanks to advances in computer power and miniaturization technology, portable electronic devices are now being used to assist physicians with various applications that extend far beyond Web browsing or sending e-mail. Handheld computers are used for electronic medical records, billing, coding, and to enable convenient access to electronic journals for reference purposes. The results of diagnostic investigations, such as laboratory results, study reports, and still radiographic pictures, can also be downloaded into portable devices for later view. Handheld computer technology, combined with wireless protocols and streaming video technology, has the added potential to become a powerful educational tool for medical students and residents. The purpose of this study was to assess the feasibility of transferring multimedia data in real time to a handheld computer via a wireless network and displaying them on the computer screens of clients at remote locations.

METHODS

A live laparoscopic splenectomy was transmitted live to eight handheld computers simultaneously through our institution's wireless network.

RESULTS

All eight viewers were able to view the procedure and to hear the surgeon's comments throughout the entire duration of the operation.

CONCLUSION

Handheld computer technology can play a key role in surgical education by delivering information to surgical residents or students when they are geographically distant from the actual event. Validation of this new technology by conducting clinical research is still needed to determine whether resident physicians or medical students can benefit from the use of handheld computers.

A technique for real-time digital measurements in laparoscopic surgery

BACKGROUND

The current techniques for the measurement of intracorporeal targets in laparoscopic surgery are relatively cumbersome and imprecise.

METHODS

A structured light technique was used to obtain the length and width of two defects and an object in a laparoscopic training box. These measurements were compared against two current and standard laparoscopic techniques of intracorporeal measurement: the introduction of a plastic ruler and the use of an opened end of a laparoscopic instrument to approximate 2 cm. The time needed to measure the defects and object was recorded.

RESULTS

Structured light-derived measurements were closest to the criterion standard, followed by plastic ruler measurements, then by instrument-end measurements. Digital measurements were quickest, followed by the instrument-end method, then by the plastic ruler.

CONCLUSIONS

This report describes a novel structured light technique for laparoscopic measurement of intracorporeal targets capable of producing results superior to those of current techniques.

Laparoscopic adrenalectomy for pheochromocytoma

BACKGROUND

Laparoscopic adrenalectomy is a safe and effective treatment for most surgical diseases of the adrenal gland. However it has been suggested that catecholamine effects associated with pheochromocytoma render the laparoscopic approach a more challenging and a more morbid procedure. The purpose of this study was to compare the operative characteristics and outcomes of laparoscopic adrenalectomy for pheochromocytoma to those of aldosteronoma and incidentaloma.

METHOD

Patient records and operative reports were retrospectively reviewed for demographics, diagnoses, operative management, and outcomes for patients undergoing laparoscopic adrenalectomy between June 1994 and July 2002 at two academic medical centers. A total of 74 patients were included and analyzed by diagnosis. Differences were considered statistically significant at p < 0.05.

RESULTS

Twenty-eight patients with pheochromocytoma, 27 with aldosteronoma, and 19 with incidentally discovered nonfunctioning adrenal masses underwent laparascopic adrenalectomy. Patients undergoing resection for pheochromocytoma trended toward more operative blood loss (150 ml) compared to aldosteronoma (88 ml) and incidentaloma (75 ml). Eight patients were converted to an open procedure for a 10.8% conversion rate. The mean operative time was 171 min and there was a 10.8% perioperative complication rate. The mean hospital stay was 3.4 days. These results were not statistically significant between diagnostic groups.

CONCLUSION

Despite concern about increased operative times and morbidity associated with pheochromocytoma, our experience supports that laparoscopic adrenalectomy may be performed as safely as, and achieve outcomes similar to, those for other diseases.

Minimal adhesions to ePTFE mesh after laparoscopic ventral incisional hernia repair: reoperative findings in 65 cases

BACKGROUND AND OBJECTIVES

Laparoscopic ventral incisional hernia repair involves intraabdominal placement of a synthetic mesh, and the possibility of formation of severe visceral adhesions to the prosthesis is a principal concern. Little clinical information based on reoperative findings is available about adhesions to biomaterials placed intraabdominally. We conducted a multi-institutional study of adhesions to implanted expanded polytetrafluoroethylene (ePTFE) mesh at reoperation in patients who had previously undergone laparoscopic incisional hernia repair done with the same mesh implantation technique.

METHODS

Nine surgeons retrospectively assessed the severity of adhesions to ePTFE mesh at reoperation in 65 patients. For each case, adhesions were assigned a score of 0 to 3, with 0 indicating no adhesions and 3 severe adhesions.

RESULTS

The mean time from mesh implantation to reoperation was 420 days (range, 2-1 739 days). No adhesions were observed in 15 cases. Forty-four cases received an adhesion score of 1, and 6 cases a score of 2; no scores of 3 were assigned. Thus, 59 patients (91 %) had either no or filmy, avascular adhesions. No enterotomies occurred during adhesiolysis.

CONCLUSIONS

In this large series of reoperations after laparoscopic incisional hernia repair, no or minimal formation of adhesions to implanted ePTFE mesh was observed in 91 % of cases, and no severe cohesive adhesions were found. Comparative analyses of newer materials based on clinical reoperative findings are warranted to assess the safety of intraabdominally placed meshes.

Laparoscopic repair of traumatic diaphragmatic injuries

BACKGROUND

The purpose of this study was to evaluate the feasibility and limitations of laparoscopic repair of traumatic diaphragmatic injuries.

METHODS

Laparoscopic repair of an acute traumatic diaphragmatic laceration or chronic traumatic diaphragmatic hernia was attempted in 17 patients between January 1997 and January 2001. The patients in the study included 13 men and 4 women with a mean age of 33.2 years (range, 15-63 years). Nine patients had a blunt injury, and eight patients had a penetrating injury. Laparoscopic repair was attempted for eight patients during their hospitalization for the traumatic injury (mean, 2.3 days; range, 0-6 days) and for ten patients with a chronic diaphragmatic hernia (mean, 89 months; range, 5-420 months). The chronic diaphragmatic hernias-presented with abdominal pain (9/9), or vomiting (3/9).

RESULTS

Thirteen traumatic diaphragmatic injuries were repaired laparoscopically, and four (2 acute and 2 chronic) required conversion. Among the laparoscopically repaired diaphragmatic injuries, three defects (chronic) were repaired using expanded polytetrafluoroethylene (ePTFE), and nine were repaired primarily. The mean length of the diaphragmatic defects was 4.6 cm (range, 1.5-12 cm). The mean operative time was 134.7 min (range, 55-200 min). The mean estimated blood loss was 108.5 ml (range, 30-500 ml), and the postoperative length of stay was 4.4 days (range, 1-12 days). There were no intraoperative complications, but three patients developed pulmonary complications (atelectasis/pneumonia). Follow-up evaluation was available for 11 patients. There were no documented recurrences after a mean follow-up period of 7.9 months (range, 1 week to 24 months). Conversion resulted from a reluctance or inability to perform laparoscopic suture of transverse diaphragmatic lacerations longer than 10 cm anterior to the esophageal hiatus and adjacent to the pericardium (n = 2) or communicating with the esophageal hiatus (n = 2). One patient also required spleneotomy for an unrecognized splenic laceration that had occurred at the time of the original trauma. The four patients undergoing laparotomy had a mean postoperative discharge date of 8.7 days (range, 6-14 days).

CONCLUSIONS

Laparoscopy is an alternative approach to repairing acute traumatic diaphragmatic lacerations and chronic traumatic diaphragmatic hernias. Large traumatic diaphragmatic injuries adjacent to or including the esophageal hiatus are best approached via laparotomy.

Salmonella enterica subspecies enterica serotype Typhimurium and Escherichia coli O86 in wild birds at two garden sites in south-west Scotland

Salmonella enterica subspecies enterica serotype Typhimurium and Escherchia coli O86:K61:NM are two bacteria that can cause outbreaks of mortality in garden birds visiting bird tables and other feeding stations. Two sites in south-west Scotland were monitored for the two organisms for 12 months. At site A, large numbers of birds fed throughout the year, and at site B smaller numbers of birds fed only in the winter months. Samples of composite faeces were collected from the feeding stations and screened for the organisms, and any dead birds were also screened. S Typhimurium definitive type (DT) 56 (variant) was found to be endemic at site A, and was recovered from 48 per cent of samples of composite faeces collected from the bird table, from 42 per cent of composite faeces from underneath a hanging feeder, and from 33 per cent of composite faeces from below a roost used by house sparrows; the organism was also isolated from the carcases of six wild birds found dead at the site. In contrast, S Typhimurium (DT41) was recovered only once at site B, from 2 per cent of the composite faeces from below a hanging feeder, and no dead birds were recovered from the site. E coli O86 was not recovered from the faeces collected from either site, but was isolated from a bird that died from trauma at site A.

Numerical analysis of an anastomotic device

The explicit dynamic finite element method was utilized to investigate the deformation behaviour of a woven wire mesh tubular device that is used in a side-to-side anastomotic procedure for achieving gastrointestinal anastomosis. The numerical model was initially verified by comparison to experimental results that were obtained using a specialized testing mechanism. Once validated, the finite element model (FEM) was parameterized to ascertain the influence of several device parameters on its deformation behaviour. The importance of these parameters, as related to its optimal design for use in minimally invasive surgery (MIS), was subsequently ascertained and discussed.

Laparoscopic adrenalectomy for pheochromocytoma

BACKGROUND

Laparoscopic adrenalectomy for Conn's syndrome, Cushing's disease, cortisol-producing adenomas, and nonfunctioning adenomas has been well established. This study was intended to evaluate the clinical outcomes of patients undergoing laparoscopic adrenalectomy for pheochromocytoma, and to assess the efficacy and safety of a minimally invasive approach.

METHODS

Data were collected prospectively on all patients undergoing laparoscopic adrenalectomy for pheochromocytoma over a 5-year period.

RESULTS

In this study, 39 consecutive patients underwent laparoscopic resection of a pheochromocytoma: 38 adrenal (23 left, 15 right) and 1 extraadrenal paraganglioma. There were no conversions to open surgery. The mean tumor size was 5.2 cm (range, 2-12.1 cm). Average operative time was 159 min (range, 100-265 min), and average estimated blood loss was 72 ml (range, 30-350 ml). Intraoperative hypertension (systolic blood pressure > 170 mmHg) occurred in 67% of the patients, and hypotension (systolic blood pressure < 90 mmHg) in 39% of the patients. The mean length of stay was 2.1 days (range, 1-4 days). There were three minor postoperative complications. During a mean follow-up period of 14 months, there were no mortalities or recurrences of endocrinopathy.

CONCLUSIONS

Laparoscopic resection of pheochromocytomas can be accomplished safely despite frequent episodes of hemodynamic variability equal to those of historic open control subjects. A short hospital stay with expedient recovery,minimal wound complications, and lack of endocrinopathy recurrence makes a minimally invasive approach the procedure of choice for the management of pheochromoctyoma.

Using semi-automated image processing and desktop systems to incorporate actual patient volumetric data in immersive surgical planning and viewing systems for multiple patients

This paper describes how patient specific volumetric data are managed from image acquisition through final processing for the purposes of creating a 3D VR rendering of user selected and manipulated 3D models. The system described here allows for the development of quick, inexpensive, and clinician manipulated patient-specific models. The utility of this process is demonstrated by being able to move VRML models to desktop or immersive environments for both pre-operative planning and patient-specific surgical and anatomical training.

Special observation in the care of psychiatric inpatients: a literature review

This paper summarizes the results of a search of electronic databases for papers on special observation (SO). Published studies to date about SO are entirely descriptive. No evaluative research appears to have taken place, leaving the procedure based on clinical pragmatism and tradition. Something between 3%-20% of admissions receive some form of SO during their stay and the rate of usage varies widely between wards. SO is used as a method of controlling and containing the most disturbed patients who are considered to be imminently at risk of harming themselves or others. Such patients tend to be younger and suffering from acute psychosis or depression. Which professional staff have the authority to initiate and terminate SO varies from place to place, as does its duration. The financial costs have been crudely assessed and are reported to be very high, perhaps up to 20% of the nursing budget for a hospital. Further variation exists on who is allowed to carry out SO. Nurses frequently make unofficial modifications to the procedure based upon their own individual judgments and assessments, and policies vary widely among hospitals. There is little agreement between authorities on what nurses should do during SO, although there is some evidence that it can, under certain circumstances, be therapeutic. However there is also evidence that nurses find SO stressful and patients dislike it.

Determinants of Staphylococcus aureus nasal carriage

Nasal carriage of Staphylococcus aureus has been identified as a risk factor for community-acquired and nosocomial infections. We screened 230 donors of diverse ethnic and socioeconomic backgrounds and identified 62 (27%) whose nasal secretions were colonized by S. aureus. In 18 donors in whom the various regions of the nasal luminal surface were separately sampled, the predominant region of S. aureus colonization was the moist squamous epithelium on the septum adjacent to the nasal ostium. Nasal fluid from carriers was defective in killing endogenous S. aureus and nasal carrier isolates of S. aureus but not a laboratory S. aureus strain. Transmission electron microscopy revealed that S. aureus isolates incubated in nasal fluid from carriers for 2 h at 37 degrees C were less damaged than those incubated in noncarrier fluid and were coated with an electron-dense layer. Compared with that from healthy donors and patients with acute rhinitis, nasal fluid from carriers contained elevated concentrations of the neutrophil-derived defensins human neutrophil peptides 1 to 3 (47- and 4-fold increases, respectively), indicative of a neutrophil-mediated inflammatory host response to S. aureus colonization. The concentration of the inducible epithelial antimicrobial peptide human beta-defensin 2 was also highly elevated compared to that in healthy donors, in whom the level was below the detection limit, or patients with acute rhinitis (sixfold increase). Thus, nasal carriage of S. aureus takes hold in nasal fluid that is permissive for colonization and induces a local inflammatory response that fails to clear the colonizing bacteria.

Protease inhibitor therapy is associated with markedly prolonged time to relapse and improved survival in AIDS patients with cytomegalovirus retinitis

Prior to the use of highly active antiretroviral therapy (HAART), cytomegalovirus retinitis (CMV-R) in AIDS patients was characterized by multiple relapses and decreased survival. Recent data suggest that CMV-R in patients treated with HAART may remain relapse-free for long periods. We performed a study of the effects of HIV protease inhibitors (PIs) on the incidence of relapse and time to death in AIDS patients with CMV-R treated with anti-CMV therapy. Medical records of all AIDS patients with CMV-R at Parkland Memorial Health and Hospital System treated with anti-CMV agents were reviewed for date of diagnosis of CMV-R, date of CMV-R relapse, type and duration of anti-CMV therapy, and duration of PI therapy. Relapse rates in subjects treated with PIs were compared with the relapse rates in those who were not treated with PIs. The primary endpoint was the time to relapse and death as determined by Kaplan-Meier analysis. Multivariate analysis was performed by Cox proportional hazard model. One hundred and nine cases of CMV-R were identified in 75 patients. Median follow-up time was 247 days (range 31-1818 days). There were 0.54 relapses per 1000 patient days in the group treated with PIs compared with 1.83 relapses per 1000 patient days in the non-PI treatment group (relative risk [RR]=0.29, P<0.01). Time to relapse was increased in the PI treatment group compared with the non-PI treatment group (endpoint not reached vs 182 days, P<0.001, log-rank). Similarly, the time to relapse or death was increased in the PI group compared with the non-PI group (543 days vs 103 days, P<0.001, log-rank). Multivariate analysis utilizing the Cox proportional hazards model demonstrated that only PI therapy but not anti-CMV therapy was associated with decreased risk of CMV-R relapse or death. Only 3 patients with an undetectable HIV viral load and one patient with a CD4 count >120 cells/microl had a relapse. We conclude that patients with CMV-R treated with HAART containing a PI have increased time to relapse and have prolonged survival.

Octylcyanoacrylate tissue adhesive as an alternative to mechanical fixation of expanded polytetrafluoroethylene prosthesis

In minimally invasive incisional hernia repair positioning and fixation of the expanded polytetrafluoroethylene (ePTFE) mesh prosthesis on the deep surface of the abdominal wall may be facilitated using tissue adhesives. Octylcyanoacrylate (OCTYL), a new adhesive, forms a strong flexible bond with antimicrobial properties. In a rabbit model for incisional hernia we investigated characteristics of the bond created by OCTYL between ePTFE and abdominal wall musculature. We studied initial bond strength and the postoperative host response to the adhesive over a 6-week period. We compared sutured, stapled, and glued mesh prostheses and examined the tissue-prosthesis interface. The ePTFE mesh was fixed successfully to the abdominal wall with OCTYL and remained tightly attached at 6 weeks. Prostheses fixed with OCTYL and spiral tacks induced few intra-abdominal adhesions compared with sutured mesh. All prostheses were completely reperitonealized at 2 weeks. The force required to displace mesh fixed with sutures and staples was greater than mesh fixed with OCTYL. Analysis of the ePTFE/tissue interface by light and scanning electron microscopy showed host cellular migration into the interstices of the mesh with fixation by tacks and suture, whereas an inflammatory infiltrate was seen on the muscular surface with OCTYL fixation of the mesh.