Aneurysm Formation After Laser-Assisted Microvascular Anastomosis: Etiology, Growth Rate, and Prevention

Aneurysm formation has been a major complication in laser-assisted micro vascular anastomosis (LAMA). The authors investigated the effect of increased laser energy on the formation and growth rate of aneurysms. In addition, possi ble methods of prevention were reviewed. End-to-end anastomoses were per formed on 89 rat femoral arteries with the placement of three stay sutures (120 degrees apart) followed by application of CO2 laser irradiation (power = 80 mW, pulse mode = 0.2 s, spot size = 0.275 m). In Group I (N=55), anasto moses were performed with 45 laser pulses, and in Group II (N = 34) 135 laser pulses were used. Each disruption of an anastomosis was repaired by use of 15 additional laser pulses. Six of 18 aneurysms in Group I were reevaluated at weeks 1, 3, and 8 to assess growth rate. All vessels were examined at week 3 for patency and aneurysm formation.

Overall aneurysm rates in the two groups were similar, despite the increased laser energy used in Group II (p > 0.05). There was a higher incidence of aneu rysm formation in disrupted vessels in both groups when compared with non- disrupted vessels (p < 0.05 in Groups I and II). The aneurysm rates did not differ between the two groups when vessels with no disruption or with 1 disrup tion were compared (p > 0.05). Mean aneurysm size increased 0.4 mm/week during the first week, 0.25 mm/week during the second and third weeks, and less than 0.1 mm/week during the remaining five weeks.

In conclusion, the authors have shown that aneurysm formation is not re lated to the total amount of laser energy applied and that disrupted anastomoses have higher aneurysm rates independent of laser energy. Aneurysm growth rate is maximal during the first week.

Infrared neural stimulation of human spinal nerve roots in vivo

Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients ([Formula: see text]) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and [Formula: see text]. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at [Formula: see text] and a [Formula: see text] safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans.

Nanoparticles in Medicine: Selected Observations and Experimental Caveats

Medically useful nanoparticles measure 1-100 nm in at least one dimension and are engineered and manufactured for specific diagnostic and treatment applications. Most nanoparticles used currently used in medicine are engineered and manufactured for specific purposes. Medically significant nanoparticles are composed of a 1) central core that is usually the medically active component, 2) one or more layers of organic or inorganic materials that forms a capsule (corona) covering the core and 3) an outer surface layer that interacts with the environment and/or targeted cells and tissues. Effective nanoparticle function in the living, intact animal or human requires electrochemical stability necessary to bypass the reticuloendothelial system (RES) and avoid filtration through the renal glomerulus into the urine. Nanoparticles are present in "natural" as well as the manufacturing and clinical environments thus could pose as significant toxins because of their small sizes, their chemical and drug content and potential effect of causing long term disease including allergies, chronic inflammation and cancer. Currently published studies have focused on the effects of nanoparticles on cells in the extremely artificial environments of cell cultures. More clinical and preclinical studies documenting the short term and long term effects nanoparticle in the intact experimental animal and human are needed.

Ultrasound guidance and monitoring of laser-based fat removal

BACKGROUND AND OBJECTIVES

We report on a study to investigate feasibility of utilizing ultrasound imaging to guide laser removal of subcutaneous fat. Ultrasound imaging can be used to identify the tissue composition and to monitor the temperature increase in response to laser irradiation.

STUDY DESIGN/MATERIALS AND METHODS

Laser heating was performed on ex vivo porcine subcutaneous fat through the overlying skin using a continuous wave laser operating at 1,210 nm optical wavelength. Ultrasound images were recorded using a 10 MHz linear array-based ultrasound imaging system.

RESULTS

Ultrasound imaging was utilized to differentiate between water-based and lipid-based regions within the porcine tissue and to identify the dermis-fat junction. Temperature maps during the laser exposure in the skin and fatty tissue layers were computed.

CONCLUSIONS

Results of our study demonstrate the potential of using ultrasound imaging to guide laser fat removal.

Optically mediated nerve stimulation: Identification of injury thresholds

BACKGROUND AND OBJECTIVE

Transient optical nerve stimulation is a promising new non-contact, spatially precise, artifact-free neural excitation technique useful in research and clinical settings. This study evaluates safety of this pulsed infrared laser technique by histopathologic examination of stimulated peripheral nerves.

STUDY DESIGN/MATERIALS AND METHODS

Exposed rat sciatic nerves were functionally stimulated with the pulsed Holmium:YAG laser, previously validated as an effective tool for optical stimulation. Nerves were removed immediately and up to 2 weeks after stimulation and assessed histologically for thermal damage. Laser parameters studied include upper limits for radiant exposure, repetition rate, and duration of stimulation.

RESULTS

Radiant exposures with <1% probability of thermal tissue damage (0.66-0.70 J/cm(2)) are significantly greater than radiant exposures required for reliable stimulation (0.34-0.48 J/cm(2)). The upper limit for safe laser stimulation repetition rate occurs near 5 Hz. Maximum duration for constant low repetition rate stimulation (2 Hz) is approximately 4 minutes with adequate tissue hydration.

CONCLUSION

Results confirm that optical stimulation has the potential to become a powerful non-contact clinical and research tool for brief nerve stimulation with low risk of nerve thermal damage.

Active zone assembly and synaptic release

Neurotransmitter release at chemical synapses occurs when synaptic vesicles fuse to the presynaptic membrane at a specialized site termed the active zone. The depolarization-induced fusion is highly dependent on calcium ions, and, correspondingly, the transmission characteristics of synapses are thought to be influenced by the spatial arrangement of voltage-gated calcium channels with respect to vesicle release sites. Here, we review the involvement of the Drosophila Bruchpilot (BRP) protein in active zone assembly, a process that is required for the clustering of presynaptic calcium channels to ensure efficient vesicle release.

Detection of vulnerable plaque in a murine model of atherosclerosis with optical coherence tomography

OBJECTIVES

The aim of this study was to evaluate the feasibility of optical coherence tomography (OCT) to identify the components of vulnerable plaques in a well-established murine model of human atherosclerosis.

BACKGROUND

Although the pathologic features that predict plaque rupture at autopsy are well known, the development of a technology to identify these high risk features in vivo is lacking. OCT uses reflected light to provide histology-like images of plaque with higher resolution than competing imaging modalities. Whether OCT can reliably identify the features of an atherosclerotic plaque that define it as vulnerable-thin fibrous cap, large lipid core, and high percent of lipid in the artery-requires further study.

METHODS

OCT images of the atherosclerotic innominate artery segments from the apolipoprotein E knockout (apoE(-/-)) mice were recorded and correlated with histology in both in vivo (n = 7) and well as in ex vivo experiments (n = 12).

RESULTS

Excellent correlation between the OCT and histology measurements for fibrous cap thickness, lipid core size, and percentage lipid content was found. The fibrous cap thicknesses examined span those of human fibrous caps known to rupture (< 65 microm). Regions of greatest light reflection in OCT images were observed when calcium hydroxy-apatite was scattered in lipid, less in fibrous tissue, and least in lipid.

CONCLUSIONS

These findings suggest that OCT holds promise for the identification of features defining vulnerable plaque including fibrous cap thickness, lipid core size, and the percentage of lipid content.

Impact of physiological variables and genetic background on myocardial frequency-resistivity relations in the intact beating murine heart

Conductance measurements for generation of an instantaneous left ventricular (LV) volume signal in the mouse are limited, because the volume signal is a combination of blood and LV muscle, and only the blood signal is desired. We have developed a conductance system that operates at two simultaneous frequencies to identify and remove the myocardial contribution to the instantaneous volume signal. This system is based on the observation that myocardial resistivity varies with frequency, whereas blood resistivity does not. For calculation of LV blood volume with the dual-frequency conductance system in mice, in vivo murine myocardial resistivity was measured and combined with an analytic approach. The goals of the present study were to identify and minimize the sources of error in the measurement of myocardial resistivity to enhance the accuracy of the dual-frequency conductance system. We extended these findings to a gene-altered mouse model to determine the impact of measured myocardial resistivity on the calculation of LV pressure-volume relations. We examined the impact of temperature, timing of the measurement during the cardiac cycle, breeding strain, anisotropy, and intrameasurement and interanimal variability on the measurement of intact murine myocardial resistivity. Applying this knowledge to diabetic and nondiabetic 11- and 20- to 24-wk-old mice, we demonstrated differences in myocardial resistivity at low frequencies, enhancement of LV systolic function at 11 wk and LV dilation at 20–24 wk, and histological and electron-microscopic studies demonstrating greater glycogen deposition in the diabetic mice. This study demonstrated the accurate technique of measuring myocardial resistivity and its impact on the determination of LV pressure-volume relations in gene-altered mice.

Magnetic Resonance–Guided Focused Ultrasound Surgery of Breast Cancer: Reliability and Effectiveness

BACKGROUND

Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a noninvasive technique that has been shown to coagulate benign and malignant tumors. The purpose of this study was to evaluate MRgFUS safety and effectiveness for the ablation of breast carcinomas.

STUDY DESIGN

Thirty women with biopsy-proved breast cancer underwent MRgFUS treatment. Gadolinium-enhanced MR images were used for treatment planning and posttreatment radiologic assessment of treated tissue, and temperature-sensitive MR images provided real-time treatment monitoring. After MRgFUS, all 30 women underwent wide excision or mastectomy. The extent of thermal ablation was assessed with tumor histology.

RESULTS

Treatment was well tolerated, with a minimum of adverse effects, especially when performed under local anesthesia. On pathologic examination, mean (+/-SD) necrosis of the targeted breast tumors was 96.9 +/- 4% (median 100%, range 78% to 100%) of tumor volume. Fifteen (53.5%) of 28 evaluable patients had 100% necrosis of the ablated tumor; only 3 patients (10.7%) had less than 95% necrosis. In 28 (93.3%) patients, 100% of the malignancy was within the treatment field, and 98% and 95% of tumor lay within the treatment field in 2 remaining patients. Retrospective analysis in two patients with residual tumor showed treatment was not delivered to the full recommended area, reaffirming the need for precise localization and the value of contrast-enhanced images for treatment planning.

CONCLUSIONS

MRgFUS has great potential to become a viable noninvasive replacement for lumpectomy. Additional studies focusing on posttreatment image-based evaluation are needed.

Histological evidence for the role of mechanical stress in modulating thermal denaturation of collagen

The hyperthermia and thermal denaturation literatures reveal a time-temperature equivalency when heating cells or connective tissues: thermal damage increases with increasing temperature (for the same duration) and increases with increasing duration (for the same temperature). Recent findings conversely suggest that increasing the mechanical loading on a tissue during heating decreases the thermal damage (for a given temperature and duration of heating). Surprisingly, however, there are few histological correlates of such damage. In this paper, we show that progressive light microscopic changes - swelling of collagen bands, thickening of collagen-rich layers, hyalinization, and loss of birefringence approximately - correlate very well with both increased heating times and decreased mechanical loading. Increased mechanical stress is thus thermally protective and should be considered in the design of clinical procedures that use heating to treat diseases or injuries.

Control of foot differentiation in Hydra: Phylogenetic footprinting indicates interaction of head, bud and foot patterning systems

Homeodomain transcription factor CnNK-2 seems to play a major role in foot formation in Hydra. Recently, we reported in vitro evidence indicating that CnNK-2 has autoregulatory features and regulates expression of the morphogenetic peptide pedibin. We proposed that CnNK-2 and pedibin synergistically orchestrate foot differentiation processes. Here, we further analyzed the regulatory network controlling foot formation in Hydra. By phylogenetic footprinting we compared the CnNK-2 5'-flanking sequence from two closely related species, Hydra vulgaris and Hydra oligactis. Unexpectedly, we detected a highly conserved binding site for HNF-3beta, a vertebrate Forkhead transcription factor, in the CnNK-2 5'-flanking region. The Hydra HNF-3beta homolog budhead is predominantly expressed in the apical region of the body column and early during budding. Budhead is absent from tissue expressing CnNK-2 and thought to be involved in determining tissue for head differentiation. By electrophoretic mobility shift assays we demonstrate an in vitro interaction between recombinant budhead protein and the interspecific conserved HNF-3beta binding motif in the CnNK-2 5'-flanking region. Our results strengthen the view of CnNK-2 as an important regulator during foot patterning processes. Furtheron, they point to budhead as a candidate for a transcriptional regulator of CnNK-2 and to an interaction of foot and head patterning processes in Hydra on the molecular level.

Laser-induced thermal injury to dermal blood vessels: Analysis of wavelength (585 nm vs. 595 nm), cryogen spray cooling, and wound healing effects

BACKGROUND AND OBJECTIVES

Successful laser treatment of cutaneous hyper-vascular lesions requires appropriate laser irradiation parameters for selective photothermolysis of ectatic dermal blood vessels as well as appropriate cooling parameters for epidermal protection based on an individual patient basis. Using the rabbit ear as an in vivo model for dermal vasculature, we investigated the influences of laser wavelength (585 nm vs. 595 nm) and cryogen spray cooling with various spurt durations on the laser-induced thermal injury to dermal blood vessels. Wound healing response was also evaluated in 2 hours and 4 days.

STUDY DESIGN/MATERIALS AND METHODS

Flashlamp-pumped pulsed dye laser ScleroPlus (operated at the wavelength of 585 or 595 nm) was used for the comparison between the influences of two wavelengths (585 nm vs. 595 nm). R134-a cryogen spurts with the durations from 50 to 300 milliseconds were sprayed onto the sites to be irradiated and terminated 20 milliseconds before the onset of the laser pulses. In vivo rabbit ear was used as the model for cutaneous hyper-vascular lesions. Totally 10 New Zealand Albino white rabbits were experimented and in each rabbit ear six to seven sites were irradiated. Five animals were sacrificed 2 hours after the irradiation, and the remaining five sacrificed 4 days after the irradiation. Thermal injury to the blood vessel was assessed by hematoxylin and eosin stained histological sections and confirmed by an apoptosis assay.

RESULTS

When the radiant exposures were above 10 J/cm2, 595 nm wavelength induced equivalent or more severe thermal injury to dermal blood vessels than 585 nm. Cryogen spray cooling with the spurt durations above 100 milliseconds resulted in increased depth of the most superficial thermal injury to dermal blood vessels than without cooling, indicating that superficial blood vessels were non-specifically cooled by the cryogen spurts applied at these parameters. Laser-induced thermal injury was significantly healed in the rabbit ear vasculature at 4 days post irradiation.

CONCLUSIONS

Given sufficient radiant exposure, 595 nm wavelength can induce equivalent or more severe vascular injury compared with 585 nm. Cryogen spray cooling with the spurt durations above 100 ms may impair the photocoagulation of superficial blood vessels. Irreversible thermal injury to blood vessel can be achieved only when the basement membrane of blood vessel wall is irreversibly damaged.

Fifty ways to leave your rubber: how men in Mombasa rationalise unsafe sex

OBJECTIVE

To explore the reasons why men who have sex with sex workers in Kenya refuse to use condoms in order to develop potential interventions that might help to overcome these barriers.

METHODS

We conducted participant observations over a period of 2 months in the bars, discos, shebeens, and guesthouses of Mombasa, Kenya, where many of the sexual transactions are initiated.

RESULTS

Analysis of the participant observations revealed at least 50 reasons for not using a condom, which we grouped into six categories: condoms are not pleasurable, condoms are defective, condoms are harmful, condoms are unnecessary, condoms are too hard to use, and external forces prohibit using condoms.

CONCLUSIONS

Some of the reasons men say they do not use condoms would be difficult to affect directly. Others are the result of gaps in knowledge and have not been impacted through better communication strategies. Finally, some of the reasons for not using condoms, such as men's weaknesses, and the loss of pleasure, could possibly be addressed through the introduction of female controlled devices. However, the most important conclusion of this paper is that men who pay for sex do so because it is pleasurable and many men do not find the male condom pleasurable. Therefore, messages targeted at men who have sex with sex workers may not be 100% successful if they only emphasise the benefits of condom use as disease control.

Control of foot differentiation in Hydra: in vitro evidence that the NK-2 homeobox factor CnNK-2 autoregulates its own expression and uses pedibin as target gene

The foot of the simple metazoan Hydra is a highly dynamic body region of constant tissue movement, cell proliferation, determination and differentiation. Previously, two genes have been shown to participate in the development and differentiation of this body region: homeodomain factor CnNK-2 and signal peptide pedibin [Dev. Biol. 180 (1996) 473; Development 126 (1999) 517; Development 122 (1996) 1941; Mech. Dev. 106 (2001) 37]. CnNk-2 functions as transcriptional regulator and is responsive to changes in the positional value while the secreted peptide pedibin serves as "extrinsic" positional signal. Exposure of polyps to pedibin increases the spatial domain of CnNK-2 expression towards the gastric region, indicating that positional signals are integrated at the cis-regulatory region of CnNK-2. In the present study, to elucidate the molecular basis of the interaction of CnNK-2 and pedibin, we characterized the 5' regulatory regions of both genes. Within the CnNK-2 5' upstream region, electrophoretic mobility shift assays showed that putative NK-2 binding motifs are specifically bound by both nuclear protein from Hydra foot and by recombinant CnNK-2, suggesting that CnNK-2 might autoregulate its own expression. This is the first indication for an autoregulatory circuit in Hydra. In addition, we also identified NK-2 binding sites in the cis-regulatory region of the pedibin gene, indicating that this gene is one of the targets of the transcription factor CnNK-2. On the basis of these results, we present a model for the regulatory interactions required for patterning the basal end of the single axis in Hydra which postulates that CnNK-2 together with pedibin orchestrates foot specific differentiation.

CT-guided radiofrequency ablation of a pulmonary metastasis followed by surgical resection

Outpatient CT-guided radiofrequency ablation (RFA) of a pulmonary metastasis followed by surgical resection and histopathological analysis was performed in a 72-year-old lady suffering from a peritoneal leiomyosarcoma. Histological workup 3 weeks post-ablation showed complete devitalization of the metastasis. This case report demonstrates that complete thermal destruction of a pulmonary metastasis by percutaneous image-guided RFA is possible.

A comparative study of the experiences of violence of English and Swedish mental health nurses

Recent studies suggest that violence in health care environments, especially mental health care, appears to be increasing. Although there is a lack of cross-cultural studies to prove it, this increase in violence would seem to be an international phenomenon. The present study sought to compare the extent and nature of violence encountered by mental health nurses in Sweden and England. Systematic studies of violence have previously been carried out independently in both countries but this was the first attempt to compare levels of violence. Clearly defined study protocols were put in place, an operational definition of 'violence' adhered to, and random samples recruited. A specially designed questionnaire was sent to every subject (Swedish nurses n=720; English nurses n=296) enquiring about the extent of nurses' exposure to violence, the nature and severity of the violence experienced, and the effect of violence on self-esteem and job satisfaction. Significant differences were found with English nurses experiencing more violence than their Swedish counterparts. Yet support for English nurses appeared to be less good than for Swedish nurses. Reasons for the differences are discussed along with possible measures to minimise the frequency of violence against nurses and the negative effects on their work.

Low Temperature Fluorescence Imaging of Freeze-trapped Human Cervical Tissues

We characterized the fluorescence intensity distribution within the epithelia and stroma of frozen human cervical tissues at the following excitation-emission wavelength pairs: 440, 525 nm and 365, 460 nm. The intensities at both excitation-emission wavelength pairs are significantly lower in the epithelia of severely dysplastic tissues, relative to that in normal and inflammatory tissues. Furthermore, there are small differences in (1) the epithelial intensity of severe dysplasia and mild dysplasia at 440, 525 nm and (2) the stromal intensity of inflammatory and severely dysplastic tissues at 365, 460 nm. A comparison of the ratio of intensities at 440, 525 nm and 365, 460 nm between the epithelia of each tissue type indicates that this ratio is lowest in severely dysplastic tissues. It is interesting to note that the epithelial and stromal intensities are comparable at 365, 460 nm; however, at 440, 525 nm, the epithelial intensity is more than a factor of two less that that of the stroma for all tissue types.

Optimizing the therapeutic approach in tinea capitis of childhood with itraconazole

BACKGROUND

Tinea capitis is the most common dermatophytosis of childhood with increasing incidence. Whereas griseofulvin is considered by many as the mainstay of treatment, newer oral antifungal agents, including fluconazole, itraconazole and terbinafine have demonstrated higher efficacy, resulting in shorter treatment durations.

OBJECTIVES

We aimed to determine the optimum regimen for the treatment of childhood tinea capitis with itraconazole.

METHODS

A mycological culture outcome-dependent combination of a 28-day continuous and facultative additional 14-day courses with itraconazole was used in 42 children (20 girls; 22 boys) aged 12-140 months (mean 66) with tinea capitis due to Microsporum canis (n = 26) and Trichophyton violaceum (n = 16). The drug was given orally according to the patients' body weight (50 mg daily for < 20 kg; 100 mg daily for > or = 20 kg) over 4 weeks. Direct microscopy and fungal culture as a parameter for efficacy were repeated 2 weeks after termination of treatment. Assessment of efficacy was based on the evaluation of results from light microscopy and culture at 8 weeks after initiation of treatment, and in the case of a further positive mycological culture at 14 and 20 weeks, respectively. A positive fungal culture at these times resulted in an additional course for 2 weeks with the initially chosen itraconazole dosage.

RESULTS

In 34 of 42 patients a single 4-week course of itraconazole resulted in a complete mycological cure of lesions as demonstrated by light microscopy and mycological culture. Four of 42 patients had to be treated by a second itraconazole course for 2 weeks, and four children received a third course of itraconazole for 2 weeks until all lesions showed negative direct microscopy and mycological culture. No abnormal haematological or biochemical results occurred. Apart from transient, completely reversible indigestion in two children, no side-effects were observed.

CONCLUSIONS

A culture-based 28-day continuous therapeutic regimen plus facultative cultural outcome-dependent additional 14-day courses of a body weight-adapted dosage of itraconazole in tinea capitis due to M. canis and T. violaceum is discussed; this offers the advantage of an effective therapy with complete negative direct microscopy as well as negative cultural results, within a shorter active treatment period (cf. previous studies with continuous administration of itraconazole).

Lack of functional Pit-1 and Pit-2 expression on hematopoietic stem cell lines

Hematopoietic stem cells (HSC) are an important target for retroviral gene transfer. However, transduction efficiency in these HSC is extremely low compared to fibroblasts or more mature hematopoietic cells. This infection block was analyzed in the HSC line FDC-Pmix. The infection frequency with the amphotropic murine leukemia virus (MLV-A) is more than 100-fold lower in FDC-Pmix cells as compared to fibroblasts. Pseudotyping with the env of the 10A1 strain (MLV-10A1), which uses both the amphotropic receptor (Pit-2) and the receptor for gibbon ape leukemia virus (Pit-1), did not improve the infection efficiency. Vectors pseudotyped with VSV G protein were found to overcome the infection block in FDC-Pmix, confirming that the block is at the level of virus binding and possibly penetration. Accordingly, we could not detect virus binding of MLV-A or MLV-10A1 to FDC-Pmix cell lines. Northern blot analysis was performed to detect whether the defect is at the level of transcription. Surprisingly, similar levels of Pit-2 receptor transcripts were detected in all cell types. The overexpression of rat Pit-2 DNA in CHO but not in FDC-Pmix cells improved amphotropic infection frequency after introducing rat Pit-2 DNA into the cells. Taken together these results show that the inefficient infection of FDC-Pmix is due to a lack of functional receptors. Either the receptor protein is incorrectly processed in these cells or a cofactor is missing in FDC-Pmix cells that is necessary for efficient binding and/or penetration.

Feelings of professional fulfilment and exhaustion in mental health personnel: the importance of organisational and individual factors

BACKGROUND

Mental health personnel are at high risk for mental illness, burnout and suicide. Previous studies of this group of professionals have indicated the importance of organisational factors in explaining burnout, or exhaustion, and work satisfaction. This study looks more systematically at the contribution of organisational and individual factors to work-related exhaustion and to professional fulfillment, an expanded version of job satisfaction.

METHODS

A cross-sectional study of 1, 051 psychiatrists and mental health nurses in the city of Stockholm was carried out by postal questionnaire with a previously validated instrument. Multiple and logistic regressions were used to identify predictors of exhaustion and professional fulfillment.

RESULTS

Organisational characteristics were found to be more important than individual characteristics in predicting exhaustion and professional fulfillment in mental health professionals.

CONCLUSIONS

The results indicate that the psychosocial work environment and well-being of mental health professionals can be improved by concentrating on organisational factors such as efficiency, personal development and goal quality.

Controlled temperature tissue fusion: argon laser welding of rat intestine in vivo. Part one

BACKGROUND AND OBJECTIVE

Thermal denaturation of proteins is recognized as a rate process governed by the local temperature-time response. Since rate processes are exponential with temperature, laser-assisted tissue welding was performed with and without temperature feedback control (TFC) to investigate the efficacy of temperature feedback in enhancing the photothermal welding process in vivo.

STUDY DESIGN/MATERIALS AND METHODS

An automated system was developed for temperature feedback controlled laser irradiation. An experimental device incorporating co-aligned laser delivery and temperature detection was used to perform argon laser welded (with and without TFC) enterotomies. The weld strength and histology of laser welded and control sutured enterotomies were compared in an in vivo rat model. Animals (n = 41) were sacrificed at 1, 3, 7, and 21 days postoperatively, and the anastomotic site was removed for bursting/leaking pressure measurements and histological examination.

RESULTS

Laser-welded (with and without TFC) and control sutured anastomoses in surviving animals healed comparably. Some laser-welded anastomoses without TFC ruptured spontaneously (4 out of 15) leading to the animals' death within the first 24-36 hours postoperatively. None of the animals in the other groups had this problem (control suture 0/6; laser with TFC 1 leak/8). The bursting/leaking pressures of the laser welded anastomoses were not significantly different than those of the sutured controls.

CONCLUSION

TFC improves the quality of laser-welded rat intestinal anastomoses in vivo in the critical first postoperative 36 hours.

Controlled temperature tissue fusion: Ho:YAG laser welding of rat intestine in vivo. Part two

BACKGROUND AND OBJECTIVE

Temperature feedback control (TFC) during laser-assisted tissue welding was implemented to eliminate exponential increases in the rate of denaturation associated with rapidly increasing temperatures. This study was undertaken to investigate and compare the weld strengths and healing responses of laser welded enterotomies with and without TFC using a cw Ho:YAG laser and to examine the effects of wavelength on weld strength and histology. The Ho:YAG experimental results were compared with a similar study using cw argon ion laser irradiation.

STUDY DESIGN/MATERIALS AND METHODS

An automated system was developed for temperature feedback controlled laser irradiation. An experimental device incorporating co-aligned laser delivery and temperature detection was used to perform cw Ho:YAG laser-welded enterotomies (with and without TFC). The weld strength and histology of laser welded and control sutured enterotomies were compared in an in vivo rat model (Ho:YAG, n = 42; argon, n = 41). Animals were sacrificed at 1, 3, 7, and 21 days postoperatively and the anastomotic site was removed for bursting/leaking pressure measurements and histological examination.

RESULTS

Argon and Ho:YAG laser-welds with and without TFC and the control sutured anastomoses healed comparably, although wound abscesses were more prevalent in the Ho:YAG group leading to delay in mucosal healing. Laser-welded anastomoses without TFC were associated with more spontaneous ruptures and leaks (argon: 4/6 ruptures; Ho:YAG: 1/4 leak, 2/4 ruptures, & 1/3 stenosis) during the survival period than those with TFC (argon: 1/3 leak; Ho:YAG: 1/5 rupture). Bursting pressures of the Ho:YAG welds were weaker at 1 week than the argon welds, but by 3 weeks, laser welds and suture anastomoses were equally strong.

CONCLUSION

From the spontaneous failure rates encountered, it is believed that TFC improves the quality and stability of laser-assisted enterotomy closures in surviving animals. However, TFC does not provide a satisfactory method to identify completion of a weld.

Autofluorescence patterns in short-term cultures of normal cervical tissue

Fluorescence spectroscopy has potential to improve cervical precancer detection. The relationship between tissue biochemistry and fluorescence is poorly understood. The goal of this study was to characterize normal cervical autofluorescence, using fresh tissue short-term tissue cultures and epithelial cell suspensions. Transverse, short-term tissue cultures were prepared from 31 cervical biopsies; autofluorescence images were obtained at 380 and 460 nm excitation. Fluorescence excitation-emission matrices were measured from normal, precancerous and cancerous cervical cell suspensions. Observed fluorescence patterns contrast those reported for frozen-thawed tissue, and were placed into groups with (1) bright epithelial and weak stromal fluorescence; (2) similar epithelial and stromal fluorescence; and (3) weak epithelial and bright stromal fluorescence. The average ages of women in the groups were 30.9, 38.0 and 49.2 years. Epithelial fluorescence intensity was similar in Groups 1 and 2, but weaker in Group 3. Stromal intensity was similar in Groups 2 and 3, but weaker in Group 1. The ratio of epithelial to stromal fluorescence intensity was significantly different for all groups. EEMs of cell suspensions showed peaks consistent with tryptophan, reduced form of nicotinamide adenine dinucleotide (phosphate) and flavin adenine dinucleotide. Short-term tissue cultures represent a novel, biologically appropriate model to understand cervical autofluorescence. Our results suggest a biological basis for the increased fluorescence seen in older, postmenopausal women.

Changes in collagen I and collagen III metabolism in patients with generalized atopic eczema undergoing medium-dose ultraviolet A1 phototherapy

Fourteen patients suffering from acute, exacerbated atopic eczema were screened for changes in collagen I and collagen III metabolism in serum (n = 11), urine (n = 11) and skin biopsies (n = 9) before and after medium-dose ultraviolet (UV) A1 phototherapy (15 exposures of 50 J/cm2 over a 3-week period, total dose 750 J/cm2). Mature collagen I and, to a lesser extent, mature collagen III were found to be decreased after the therapy in skin samples from the irradiated patients. As markers of collagen I degradation, the cross-links pyridoline and deoxypyridoline were analysed in urine using high-performance liquid chromatography. Both cross-links were found to be mildly increased after UVA1 phototherapy, without reaching statistical significance. As markers of de novo collagen synthesis we screened for the procollagen I-carboxyterminal peptide (PICP) and procollagen III-aminoterminal peptide (PIIINP) levels in serum and skin. The ratio of PICP to PIIINP in serum dropped significantly after the UVA1 phototherapy, suggesting a different impact of UVA1 on the two collagens. These findings were paralleled by a diminished ratio of PICP to PIIINP in tissue samples. Staining for matrix metalloproteinase 1 (MMP-1) and its specific counterpart, tissue inhibitor of MMP-1 (TIMP-1), showed slight increases for both proteins by therapeutic UVA1; this was also seen in serum for TIMP-1 but not MMP-1. In our study, high-energy UVA1 doses induced changes of the skin collagens in patients with atopic eczema which are measurable by their metabolites in serum and urine.

An examination of nonresponse in a work environment questionnaire mailed to psychiatric health care personnel

Nonresponse to surveys, which seems to plague work environment studies and studies of health care personnel in particular, may pose problems of generalizability and validity. The aim of this study was to provide an estimate of nonresponse error in a self-administered survey concerning the work environment of psychiatric health care personnel. A random sample of 10% of the original survey population (N = 693) was selected to participate in a telephone follow-up of a postal survey that had a response rate of 51%. There were no differences between the responders and nonresponders to the postal survey on the exposure or outcome variables. There was no evidence of nonresponse bias in this study, although recall bias may have been a problem. In those cases in which generalizability is deemed important, it is recommended that nonresponse studies be regularly carried out when response rates are less than 100%.

An examination of nonresponse in a work environment questionnaire mailed to psychiatric health care personnel

Nonresponse to surveys, which seems to plague work environment studies and studies of health care personnel in particular, may pose problems of generalizability and validity. The aim of this study was to provide an estimate of nonresponse error in a self-administered survey concerning the work environment of psychiatric health care personnel. A random sample of 10% of the original survey population (N = 693) was selected to participate in a telephone follow-up of a postal survey that had a response rate of 51%. There were no differences between the responders and nonresponders to the postal survey on the exposure or outcome variables. There was no evidence of nonresponse bias in this study, although recall bias may have been a problem. In those cases in which generalizability is deemed important, it is recommended that nonresponse studies be regularly carried out when response rates are less than 100%.

Violence in mental health care: the experiences of mental health nurses and psychiatrists

Violence against mental health service personnel is a serious workplace problem and one that appears to be increasing. This study aimed to ascertain the extent and nature of violence against mental health nurses and psychiatrists, and to identify what support, if any, they received following exposure to violence. Mental health staff working within five West Midlands Trusts in the United Kingdom were surveyed using a postal questionnaire to investigate the extent and nature of violence they encountered in their daily work. There was an overall response rate of 47%, which included a response rate for psychiatrists of 60% (n=74) and for mental health nurses of 45% (n=301). Though both groups experienced violence at work, nurses were found: to have been exposed to violence significantly more during their career; to have been a victim of violence within the previous 12 months of the survey; and to have suffered a violent incident involving physical contact. Whilst a higher proportion of nurses than psychiatrists received some support following a violent incident, a large proportion of both groups did not receive any, although most felt in need of it. The implications of this study for training and management are discussed.

Individual and organizational well-being in psychiatric nursing: a cross-cultural study

Although health care systems around the world are undergoing rapid changes, there is an absence of comparative studies of how these changes affect nurses' well-being and work life. The purpose of this study was (i) to identify and describe possible differences between the psycho-social work environments of English and Swedish mental health nurses, and (ii) to attempt to explain these differences. 1016 psychiatric nurses from Stockholm (Sweden) and Birmingham (England) responded to a postal questionnaire on their psycho-social work environment and feelings of professional fulfillment, mental energy and work-related exhaustion. The study was given ethical clearance in Stockholm and Birmingham. Results indicated that while the English nurses rated their organizational well-being more favourably, Swedish psychiatric nurses reported greater individual well-being than their counterparts. Multiple regression analyses indicated that self-esteem was important for explaining mental energy and work-related exhaustion, but less so for explaining professional fulfillment, which was predicted primarily by organizational factors. When controlling for self-esteem, which was higher amongst the Swedish nurses, the differences in professional fulfillment and mental health were no longer significant. Reasons for the differences in self-esteem and experiences of the workplace are discussed. Low response rate may have contributed to a selection bias.

Activation of caspase-3 in axotomized rat retinal ganglion cells in vivo

Recently, we have shown that inhibition of caspase-3-like caspases is the most effective treatment strategy to protect adult rat retinal ganglion cells from secondary death following optic nerve transection. In the present study, we localized active caspase-3 in axotomized retinal ganglion cells in vivo and demonstrated a co-localization of the active p20 fragment and TUNEL-staining in some of these cells. In line with this, we detected an enhanced cleavage and activity of caspase-3 protein in retinal tissue after lesion, while caspase-3 mRNA expression remained unchanged. These data suggest caspase-3 as an important mediator of secondary retinal ganglion cell death following axotomy in vivo.

Making family-centred care a reality

The role of families in caring for their sick children has evolved over the last century. Where once they were banned from hospitals, families now play an integral part in the care of their children, whether in hospital or at home.

Computer-controlled bipolar endotubal sterilization is successful in a rabbit model

OBJECTIVE

To determine the efficacy of a computer-controlled bipolar endotubal catheter system designed to accomplish safe, effective, and inexpensive female sterilization in preventing pregnancy in a rabbit model.

DESIGN

Prospective controlled study.

SETTING

University animal care facility.

ANIMAL(S)

Sixty healthy virginal female New Zealand white rabbits.

INTERVENTION(S)

Rabbits were assigned to the following groups: [1] endotubal radiofrequency minimal energy (95 degrees C) treatment; [2] endotubal radiofrequency maximal energy (105 degrees C) treatment; [3] endouterine radiofrequency (105 degrees C) treatment; [4] nonsurgical control; [5] laparotomy-only control; [6] endotubal radio-frequency sham control; and [7] external Kleppinger forceps bipolar cautery control. Rabbits were mated at 4 or 12 weeks after treatment.

MAIN OUTCOME MEASURE(S)

Pregnancy outcomes in treated animals and nontreated controls.

RESULT(S)

No pregnancies were observed in any of the uterine horns in which minimal or maximal energy was delivered to the fallopian tubes or uterus, although pregnancy occurred in one horn as a result of the delivery of energy below the radiofrequency minimum of 95 degrees C. The outcomes of the treatment groups were significantly different from those of the nonsurgical and sham surgical control groups.

CONCLUSION(S)

With adequate tissue heating, 100% sterilization efficacy was achieved with a new, computer-controlled bipolar catheter, whereas pregnancies occurred in all untreated control groups. If human studies support these results, the goal of a safe, effective means of transcervical sterilization may be realized.

A comparative study of the perceptions of British mental health nurses and psychiatrists of their work environment

This comparative study of the perceptions of mental health nurses and psychiatrists about aspects of their work environment was undertaken in the West Midlands in England. The aim of the study was to ascertain the extent to which the environment in which mental health professionals' work impacts on their own mental and physical well-being. Seventy-four psychiatrists and 301 mental health nurses responded to a postal questionnaire. Analysis of data indicated that significant differences exist between nurses and psychiatrists in their working conditions, their physical working environment, their sources of support with a work-related problem, and the effects of their work on their own mental and physical health. The main recommendation derived from this study was to improve communication between mental health professionals and their managers by giving more structured feedback and guidance about one's work performance. This may help to alleviate the mental strain many mental health professionals experience in their work.

Murine leukemia virus recombinants that use phosphate transporters for cell entry induce similar spongiform encephalomyelopathies in newborn mice

Amphotropic Moloney-murine leukemia virus recombinants (Mo-AmphoV) induce a severe spongiform encephalomyelopathy in newborn mice. We show here that a coisogenic recombinant with a 10A1-MuLV host range (Mo-10A1V) also induces a neurodegenerative disease, clinically characterized by mild tremor and ataxia. Spongiform lesions are most severe in the metencephalon and mesencephalon but extend into the prosencephalon and spinal cord. Significantly, the quality of histopathology was indistinguishable between Mo-AmphoV and Mo-10A1V, probably reflecting a final common pathogenic pathway. Common receptor use thus may be an important determinant in the pathogenicity of these viruses. These results have implications for the clinical use of retroviral pseudotypes that use phosphate transporters for cell entry.

Predictors of a healthy workplace for Swedish and English psychiatrists

BACKGROUND

Few studies have attempted to analyse the organisational aspects of the workplace that may affect the well-being of psychiatrists and even fewer have offered insights into what a positive workplace might look like. This study provides an outline of such a workplace, with reference to individual and organisational factors. In addition, a comparison is made between two European cities to check for cultural differences.

METHOD

Three hundred and eighty psychiatrists from Stockholm and Birmingham responded to a previously tested questionnaire on their work environment.

RESULTS

Predictors of a positive workplace for psychiatrists were: high self-esteem, satisfactory support with work-related problems, lower perceived workload, positive view of leadership, low work-related exhaustion and having a sense of participation in the organisation. There were few cultural differences.

CONCLUSIONS

Measures should be taken to improve leadership skills for managers, to offer more support for work-related problems, and to allow psychiatrists to participate more in the organisation.

Near-infrared Raman spectroscopy for in vitro detection of cervical precancers

In this study, we investigate the potential of near-infrared Raman spectroscopy to differentiate cervical precancers from normal tissues, inflammation and metaplasia and to differentially diagnose low-grade and high-grade precancers. Near infrared Raman spectra were measured from 36 biopsies from 18 patients in vitro. Detection algorithms were developed and evaluated relative to histopathologic examination. Algorithms based on empirically selected peak intensities, ratios of peak intensities and a combination of principal component analysis for data reduction and Fisher discriminant analysis for classification were investigated. Spectral peaks were tentatively identified from measured spectra of potential chromophores. Empirically selected normalized intensities can differentiate precancers from other tissues with an average sensitivity and specificity of 88 +/- 4% and 92 +/- 4%. Ratios of unnormalized intensities can differentiate precancers from other tissues with a sensitivity and specificity of 82% and 88% and high-grade from low-grade lesions with a sensitivity and specificity of 100%. Using multivariate methods, intensities at eight frequencies can be used to differentiate precancers from all other tissues with a sensitivity and specificity of 82% and 92% in an unbiased test. Raman algorithms can potentially separate benign abnormalities such as inflammation and metaplasia from precancers. Comparison of tissue spectra to published and measured chromophore spectra indicate that the most likely primary contributors to the tissue spectra are collagen, nucleic acids, phospholipids and glucose 1-phosphate. These results suggest that near-infrared Raman spectroscopy can be used for cervical precancer diagnosis and may be able to accurately separate samples with inflammation and metaplasia from precancer.

Controlled radiofrequency endotubal sterilization

STUDY OBJECTIVE

A safe, effective, inexpensive method of transcervical tubal sterilization could have a major impact on women's health. In this study, we evaluated the efficacy of a new radiofrequency catheter prototype designed for endotubal sterilization using animal models.

SETTING

Animal research laboratory.

DESIGN

Prospective observational study.

METHOD

The optimal energy delivery to create a complete circumferential transmural thermal lesion in the tube was determined in 114 in vitro acute studies using porcine and bovine fallopian tubes. A study was then initiated with eight mini-pigs. Thirty-four lesions were made in the fallopian tubes using computer-controlled power delivery. Three weeks later the animals were euthanized and evaluated.

MEASUREMENTS AND MAIN RESULTS

A hydrosalpinx was evident in 8/11 of the tubes with separate proximal and distal cautery, implying occlusion at each of these sites. Complete occlusion of the tubes was seen at 12/22 sites evaluated by histology. Narrowing was seen in 9/22, and 1/22 was open.

CONCLUSION

The endotubal cautery prototype creates a reproducible lesion, but did not always cause complete closure of the tube in this preliminary study. However, based on our results, we hypothesize that a radiofrequency catheter can be developed for minimally invasive transcervical sterilization.

Physiological and pathological factors of human breast disease that can influence optical diagnosis

The 'normal' human female breast is a very complex organ that changes considerably during development, pregnancy and menopause. In addition, it is an excretory organ that, during lactation, discharges various metabolites and certain drugs that can be optically active. Optical diagnosis of breast cancers requires detection of differential concentrations of 1) various absorbers and scatterers or 2) native or exogenous fluorophores to distinguish cancers from surrounding 'normal' and benign breast tissues. The differential concentrations are due to the biology of the cancer cells and the host responses to the cancer growth. For most patients, the cancer will be intermixed with a complex 3-dimensional array of 'normal' breast tissue and benign breast lesions. This complexity will challenge the optical biopsy investigator but, with the recent advances in our understanding of light transport, optical diagnostic techniques and devices can be developed to complement and supplement current breast cancer screening techniques.

Entry of amphotropic and 10A1 pseudotyped murine retroviruses is restricted in hematopoietic stem cell lines

Although transduction with amphotropic murine leukemia virus (MLV) vectors has been optimized successfully for hematopoietic differentiated progenitors, gene transfer to early hematopoietic cells (stem cells) is still highly restricted. A similar restriction to gene transfer was observed in the mouse stem cell line FDC-Pmix compared with transfer in the more mature myeloid precursor cell line FDC-P1 and the human erythroleukemia cell line K562. Gene transfer was not improved when the vector was pseudotyped with gp70SU of the 10A1 strain of MLV, which uses the receptor of the gibbon ape leukemia virus (Pit1), in addition to the amphotropic receptor (Pit2). Although 10A1 and amphotropic gp70SU bound to FDC-P1, K562, and fibroblasts, no binding to FDC-Pmix cells was detected. This indicates that FDC-Pmix cells lack functional Pit2 and Pit1 receptors. Pseudotyping with the vesicular stomatitis virus G protein improved transduction efficiency in FDC-Pmix stem cells by 2 orders of magnitude, to fibroblast levels, confirming a block to retroviral infection at the receptor level.

[Esophageal perforations]

An oesophageal perforation is a serious condition with high morbidity and mortality. During the latest decades an increased number of traumatic perforations as well as wide use of endoscopic procedures have increased the incidence of oesophageal perforation. An early diagnosis and treatment is important for the prognosis. Cervical and selected thoracic perforations can be treated conservatively although the majority should be operated. Primary closure can be performed if done before 24 hours have elapsed, while later treatment is controversial. Drainage of the mediastinum and pleural space, as well as diversion of saliva and gastric content is important. The literature is reviewed in relation to etiology, diagnosis, treatment and prognosis.

[Benign esophageal perforations treated at a department of thoracic surgery]

Between January 1, 1980 and December 31, 1994, 37 patients with benign oesophageal perforation underwent different kinds of treatment. The overall mortality was 30%. When diagnosed less than 12 hours after the perforation the mortality was 21%, between 12 and 24 hours. Reinforced primary repair gave the best results without any deaths in seven cases where it was performed. Oesophageal perforation is a serious condition, and it is important to know the symptoms. If there is any suspicion of the condition, an oesophageal X-ray with watersoluble contrast medium should be performed on liberal indication. When diagnosed the patient should be transferred to a Department of Thoracic Surgery immediately. Only few patients can be treated conservatively and most should be operated with reinforced primary suture and drainage.

Controlled temperature tissue fusion: argon laser welding of canine intestine in vitro

BACKGROUND AND OBJECTIVE

Thermal denaturation of proteins is recognized as a rate process governed by the local temperature-time response and is believed to be the principal mechanism for photothermal tissue welding. Since rate processes are exponential with temperature, feedback control of tissue surface temperature is hypothesized to create a quasi-constant rate of denaturation that will enhance the tissue welding process.

STUDY DESIGN, MATERIALS AND METHODS

Controlled temperature tissue welding of severed edges of fresh canine jejunum was performed in vitro by remote sensing of tissue surface temperature with an infrared sensor. A hardware controlled temperature feedback system opened and closed a shutter located in the beam path of an argon ion laser to provide constant temperature welding.

RESULTS

Strong tissue fusion was not possible at or below a surface temperature of 70 degrees C, but was accomplished at 80 degrees, 90 degrees, and 95 degrees, and 100 degrees C. Fusion was achieved with thermal coagulation of the collagenous submucosa and mucosal tissues. The bursting strength of welds created at 90 degrees C and 95 degrees C were significantly stronger than those performed at 80 degrees C.

CONCLUSION

Laser-assisted intestinal anastomoses created in vitro are optimally strong at 90-95 degrees C feedback control temperatures.