Moderate alcohol consumption, estrogen replacement therapy, and physical activity are associated with increased insulin sensitivity: is abdominal adiposity the mediator?

OBJECTIVE

To investigate 1). associations between environmental factors (alcohol consumption, hormone replacement therapy [HRT], and physical activity) and insulin resistance and secretion, independent of genetic influences; 2). the contribution of abdominal adiposity to these relationships; and 3). whether gene-environment interactions mediate these associations.

RESEARCH DESIGN AND METHODS

Reported effects of lifestyle factors on insulin resistance and secretion are inconsistent, possibly due to difficulty in dissecting environmental from genetic influences and to confounding by adiposity. We examined these relationships in 798 nondiabetic female twins. Insulin resistance and secretion were estimated by modified homeostasis model assessment (HOMA-R' and HOMA-beta', respectively). Percent total body fat and percent central abdominal fat (CAF) were measured by dual-energy X-ray absorptiometry.

RESULTS

All categories of alcohol consumption were associated with lower insulin levels and HOMA-beta' than abstinence. Only moderate alcohol consumers (11-20 units/week) had lower HOMA-R' than abstainers (-0.16 +/- 0.09 vs. 0.14 +/- 0.13 SD, P = 0.048). This difference was attenuated after controlling for percent CAF (P = 0.57), which was lower in moderate drinkers. Controlling for genetic and smoking effects in cotwin case-control analysis, monozygotic pairs discordant for alcohol consumption had greater within-pair differences in HOMA-R' than concordant pairs (P = 0.02). Postmenopausal women using estrogen-only HRT had lower HOMA-R' than non-HRT users (-0.33 +/- 0.16 vs. 0.17 +/- 0.08 SD, P = 0.003), even after controlling for percent CAF. Lower fasting glucose levels and insulin resistance and secretion indexes in physically active subjects were partly explained by lower abdominal adiposity.

CONCLUSIONS

Moderate alcohol consumption, estrogen replacement, and physical activity are associated with increased insulin sensitivity in female twins. The favorable effects of moderate alcohol consumption and physical activity on insulin sensitivity are partly mediated by lower abdominal adiposity.

Solid-state temporomandibular joint imaging: accuracy in detecting osseous changes of degenerative joint disease and determining condylar spatial relations

The purpose of this study was to evaluate the off-label use of an intraoral charge-coupled device (CCD) for extraoral transcranial radiography of the temporomandibular joint. Corrected linear tomograms and transcranial images made with conventional screen-film combinations and a CCD detector were compared with sectioned cadaver specimens. Radiation dosage, qualitative assessment of condylar degenerative features, and condylar position within the glenoid fossa of the 3 modalities were assessed and compared. The CCD method required special adjustments to achieve adequate quality, and it involved greater exposure than the other methods. This use of this intraoral system for extraoral imaging cannot now be recommended, but future refinements might make it more viable.

Physical activity reduces genetic susceptibility to increased central systolic pressure augmentation: a study of female twins

OBJECTIVES

We sought to examine associations between the augmentation index (AI) and metabolic, adiposity, and lifestyle factors, independent of genetic influences, and to determine whether gene-environment interactions modulate these relationships.

BACKGROUND

Reported associations between AI, an index of systemic arterial stiffness, and metabolic, adiposity, and lifestyle factors remain contradictory. The modulating effect of genetic risk is unknown.

METHODS

We studied 684 female twins (age 18 to 71 years); AI was derived from the pressure waveform measured at the radial artery by applanation tonometry. Percentage of total body fat (TBF) and percentage of central abdominal fat (CAF) were assessed by dual-energy X-ray absorptiometry.

RESULTS

In univariate analysis, age-adjusted AI was significantly associated with fasting triglyceride levels (r = 0.1, P = 0.03), apolipoprotein-B/A1 (r = 0.1, P = 0.04), percentage of TBF (r = 0.11, P = 0.006), and percentage of CAF (r = 0.11, P = 0.004). In co-twin case-control (monozygotic twin) analysis, a 3.1% absolute within-pair difference in percentage of CAF accounted for a 6% within-pair difference in AI, independent of genetic effects. Smokers and subjects with alcohol intakes >15 U/week had higher AI than nonsmokers (p = 0.01) and nondrinkers (p = 0.02), respectively. Forty percent of the variance in AI was explained by age, central mean arterial pressure, heart rate, height, percentage of CAF, and smoking. In gene-environment interaction analysis, subjects at high genetic risk of increased AI participating in regular leisure-time physical activity had AI values similar to low genetic risk subjects.

CONCLUSIONS

Central abdominal adiposity is a significant determinant of AI in female twins, independent of hemodynamic, lifestyle, and, importantly, genetic effects. Smoking is associated with increased AI, even after controlling for abdominal obesity and other AI determinants. Physical activity reduces genetic predisposition to increased AI.

Stroke in young patients with hyperhomocysteinemia due to cystathionine beta-synthase deficiency

BACKGROUND

Although hyperhomocyst(e)inemia (Hyper-Hcy) may predispose to atherosclerosis and venous thrombosis, the mechanisms of stroke associated with Hyper-Hcy are not defined.

METHODS

Clinical and biochemical phenotypes and genetic features of three unrelated patients with premature stroke and severe Hyper-Hcy due to cystathionine beta-synthase (CBS) deficiency are described. Plasma Hcy and amino acids were measured by fluorescence polarization immune assay and ion exchange chromatography. Analysis of the CBS and methylenetetrahydrofolate reductase genes was performed by restriction enzyme digestion and sequence analysis.

RESULTS

Two of the three index cases had no known diagnosis of homocystinuria and initially presented with embolic cerebral and retinal infarction in mid-adulthood. Mechanisms of cerebrovascular disease were carotid intraluminal thrombosis, arterial dissection, and possible cardiac embolism. Family screening revealed additional members with clinically silent homocystinuria and severe Hyper-Hcy. Excluding tall stature in two individuals, all had mild phenotypes, without classic findings of CBS deficiency. Plasma total and free Hcy, methionine, and urine Hcy were elevated. Genotyping revealed heterozygous CBS mutations (I278T, D444N, G307S) in affected individuals.

CONCLUSION

Artery-to-artery embolism and dissection may cause stroke in young adults with homocystinuria. The results also support a rationale for screening for Hyper-Hcy in young adults with stroke without a phenotype suggestive of classic homocystinuria.

Complications of deep brain stimulation surgery

Although technological advances have reduced device-related complications, DBS surgery still carries a significant risk of transient and permanent complications. We report our experience in 86 patients and 149 DBS implants. Patients with Parkinson's disease, essential tremor and dystonia were treated. There were 8 perioperative, 8 postoperative, 9 hardware-related complications and 4 stimulation-induced side effects. Only 5 patients (6%) sustained some persistent neurological sequelae, however, 26 of the 86 patients undergoing 149 DBS implants in this series experienced some untoward event with the procedure. Although there were no fatalities or permanent severe disabilities encountered, it is important to extend the informed consent to include all potential complications.

Spin-dependent transparency of ferromagnet/superconductor interfaces

We combine parameter-free calculations of the transmission and reflection matrices for clean and dirty interfaces with a scattering-theory formulation of Andreev reflection (AR) generalized to spin-polarized systems in order to critically evaluate the use of an extended Blonder-Tinkham-Klapwijk (BTK) model to extract values of the spin polarization for ferromagnetic metals from measurements of point-contact AR. Excellent agreement with the experimental conductance data is found for Pb/Cu but it is less good for Pb/Ni and poor for Pb/Co, indicating that the BTK formalism does not describe transport through superconducting/ferromagnetic interfaces correctly.

Homocysteine, MTHFR 677C-->T polymorphism, and risk of ischemic stroke: results of a meta-analysis

BACKGROUND

Data are conflicting concerning risk for ischemic stroke associated with hyperhomocyst(e)inemia (hyper-Hcy) and a common polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase (MTHFR 677C-->T), which predisposes to hyper-Hcy in vivo.

METHODS

Search of MEDLINE, Science Citation Index, and abstracts of conference proceedings revealed relevant articles. Exposure was defined as follows: 1) prevalence of hyper-Hcy; 2) absolute difference in the mean Hcy concentration between subjects with and without ischemic stroke; and 3) the MTHFR TT genotype frequency. Outcome was defined as ischemic stroke with or without neuroimaging. Inclusion criteria were retrospective and prospective studies with reported odds ratios (OR) or hazard ratios (HR) or arithmetic mean Hcy levels. Exclusion criteria were absence of OR or HR, outcome defined as carotid atherosclerosis or intima-media thickening, stroke in patients younger than 18 years old, and studies in languages other than English. Statistical analyses for between-study heterogeneity and pooled risk estimates were performed using Stata software (Stata Corporation, College Station, TX).

RESULTS

Among 16 studies (1,487 stroke and 2,554 nonstroke cases), the pooled mean Hcy level in patients with ischemic stoke was 2.32 micromol/L (95% CI, 1.6 to 3.04; p < 0.001) greater than that in those without ischemic stroke. Among 14 included studies (1,769 stroke and 7,400 nonstroke cases), the pooled OR estimate of ischemic stroke associated with hyper-Hcy was 1.79 (95% CI, 1.61 to 2.0; p < 0.001). Among 19 included studies (2,788 stroke and 3,962 nonstroke cases), the OR associated with the TT genotype was 1.23 (95% CI, 0.96 to 1.58; p = 0.1).

CONCLUSION

These data support an association between mild-to-moderate hyper-Hcy and ischemic stoke. The MTHFR TT genotype may have a small influence in determining susceptibility to ischemic stoke.

Social influences on the sexual behaviors of adolescent girls in at-risk circumstances

OBJECTIVE

To describe social influences on girls' sexual behaviors.

DESIGN

Descriptive, exploratory study using interviews with five focus groups.

SETTING/PARTICIPANTS

48 adolescent girls, ages 12 to 16 years, who were confined in a juvenile detention center for a variety of charges.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Girls' perceptions of influences on their sexual behaviors.

RESULTS

The analysis revealed three themes: the influence of traditional gender roles, a lack of power in heterosexual relationships, and an ongoing search for romance.

CONCLUSIONS

The social context of adolescent girls' lives can promote sexual activity and unprotected sex. Effective prevention efforts must acknowledge the context within which sexual risk occurs and address motivations and barriers in the target population.

Caries incidence following restoration of shortened lower dental arches in a randomized controlled trial

CONTEXT

Removable partial dentures used to restore the shortened lower dental arch may adversely affect the remaining natural teeth and are associated with a low prevalence of use.

OBJECTIVE

To report the findings for caries incidence 2 years after restoration of lower shortened arches with bilateral cantilever resin-bonded bridges (RBBs) and conventional partial dentures (RPDs).

DESIGN

Randomised controlled trial.

SETTING

Secondary care

PATIENTS

25 male and 35 female subjects of median age 67 years. were randomly allocated to 'bridge' and 'denture' treatment groups of 30 patients each matched for age and sex. Caries incidence was recorded during dental examinations 3 months, 1 and 2 years after insertion of new lower prostheses.

INTERVENTIONS

Cantilever RBBs and conventional RPDs with cast metal frameworks.

RESULTS

There was a highly significant difference in the frequency of new caries lesions, 11 and 51 in the bridge and denture groups respectively (P < 0.01). 20 out of 27 bridge patients and 9 of 23 denture patients had no caries experience. Multivariate modeling identified treatment group as the only significant predictor of caries occurrence.

CONCLUSIONS

Two years after restoration of lower shortened arches for an elderly sample of patients, there was a significantly greater incidence of new and recurrent caries lesions in subjects restored with RPDs compared with cantilever RBBs.

A comparative study of two powered toothbrushes and one manual toothbrush in young adults

The aim of this 3-group, 3-treatment, single-blind, parallel group study was to evaluate and compare the efficacies of the Philips/Jordan HP735 powered toothbrush, the Braun/Oral-B D7 powered toothbrush, and the Oral-B Advantage B35 manual toothbrush in young adults (18-25 years). Full mouth mean (SD) modified Turesky Plaque Index (PI) and the Löe & Silness Gingival Index (GI) were recorded at baseline. After 24 hours abstinence from oral hygiene, the PI was recorded and each subject was given one of the test brushes with detailed instructions for use. Each subject then brushed under supervision for 90 seconds, during which time mean (SD) toothbrushing forces (TBF) were recorded. PIs were recorded immediately after brushing, and the subjects were then discharged for 6 weeks to use the allocated toothbrush at home. After 6 weeks, PI, GI and TBF were again recorded. There were no significant differences (ANOVA) for PI and GI between groups at baseline, or for PI following brushing at 24 hours. After 6 weeks, the powered brushes produced lower mean PI (SD) scores than the manual brushes, but the differences were significant only at interproximal sites. Mean GI scores for the HP735 group were similar at baseline and at 6 weeks, although for the other brushes the GI scores actually increased over this period. Mean (SD) TBF (grams/force) at baseline and 6 weeks, respectively, for the brushes were; HP735 233 (205), D7 159 (58), B35 279 (122) (p = 0.026): HP735 194 (86), D7 141 (57), B35 297 (113) (p = 0.0001). The within-group variability for the HP735 TBF reduced considerably over 6 weeks, which is possibly because of the click-force threshold feature of this brush.

Pharmacokinetics of the novel, high-affinity and selective dopamine D3 receptor antagonist SB-277011 in rat, dog and monkey: in vitro/in vivo correlation and the role of aldehyde oxidase

1. In vitro studies with the selective dopamine D3 receptor antagonist SB-277011 were conducted in liver microsomes and homogenates from rat, dog, cynomolgus monkey and human to correlate the rate of metabolism with the in vivo pharmacokinetics of the compound in rat, dog and cynomolgus monkey. 2. In the presence of NADPH, SB-277011 was relatively stable in the presence of liver microsomes from rat, dog, cynomolgus monkey and human with an intrinsic clearance (CLi) of < 2 ml min(-1) g(-1) liver for all species. In total liver homogenates, SB-277011 was metabolized at a similar rate in rat and dog (CLi < 2 ml min(-1) g(-1) liver) to that in liver microsomes but in cynomolgus monkey and human (CLi = 9.9 and 45 ml min(-1) g(-1) liver, respectively) the intrinsic clearance was approximately 6- and 35-fold higher, respectively, than that in liver microsomes. 3. In the absence of NADPH, SR-277011 was rapidly cleared in liver homogenates from cynomolgus monkey and human (CLi = 7.4 and 27 ml min(-1) g(-1) liver, respectively) demonstrating that a significant pathway of metabolism of this compound was via an NADPH-independent non-microsomal oxidative route. This pathway was sensitive to inhibition with isovanillin suggesting that the enzyme responsible was aldehyde oxidase. 4. The in vivo pharmacokinetics showed that the plasma clearance of SB-277011 was low in rat (20 ml min(-1) kg(-1)), moderate in dog (14 ml min(-1) kg(-1)) and high in cynomolgus monkey (58 ml min(-1)kg(-1)), which is consistent with the in vitro findings and demonstrated a greater capacity for the monkey to metabolize this compound. The oral bioavailability of SB-277011 in rat, dog and cynomolgus monkey was 35, 43 and 2%, respectively. Given the high clearance of this compound in cynomolgus monkey, the low oral bioavailability is probably as a result of high first-pass elimination, specifically by aldehyde oxidase, rather than poor absorption. 5. The high in vitro clearance of SB-277011 in human liver homogenates and the involvement of aldehyde oxidase in the metabolism of SB-277011 indicates that the bioavailability of the compound is likely to be low in human.

CaB6: a new semiconducting material for spin electronics

Ferromagnetism was recently observed at unexpectedly high temperatures in La-doped CaB6. The starting point of all theoretical proposals to explain this observation is a semimetallic electronic structure calculated for CaB6 within the local density approximation. Here we report the results of parameter-free quasiparticle calculations of the single-particle excitation spectrum which show that CaB6 is not a semimetal but a semiconductor with a band gap of 0.8+/-0.1 eV. Magnetism in La(x)Ca1-xB6 occurs just on the metallic side of a Mott transition in the La-induced impurity band.

Sleeping like a baby: attitudes and experiences of bedsharing in northeast England

This paper reports findings from a study that investigated infant care practices in a small population of Northeast England in order to determine whether parent-infant bedsharing is common parenting behavior. In a year-long prospective study we examined the opinions and practices of parents with regard to their infants' nighttime sleeping strategies before and after the birth of their babies. Results confirm that parents pursue a heterogeneous array of nighttime parenting strategies and that 65 percent of the sample had actually bedshared. Parents with no previous intention to do so slept with their babies for a variety of reasons. One of this study's most important findings is that babies were being brought into bed with both parents. Ninety five percent of the bedsharing infants slept with both mother and father. This study has shown that bedsharing is a relatively common parenting practice. Despite initial worries and fears, mainly concerning overlaying, some parents found bedsharing an effective option yet were covert in their practices, fearing the disapproval of health professionals and relatives.

Effects of warming therapy on pressure ulcers--a randomized trial

Postoperative pressure ulcers are a common and expensive problem. Intraoperative hypothermia also is a common problem and may have a connection with impaired tissue viability. Researchers in this study hypothesized that intraoperative control of hypothermia may reduce the incidence of postoperative pressure ulcers. A randomized clinical trial (n = 338) was used to test the effects of using forced air warming therapy versus standard care. Results indicated an absolute risk reduction in pressure ulcers of 4.8% (i.e., 10.4% to 5.6%) with a relative risk reduction of 46% in patients who received warming therapy. Although not reaching statistical significance, the clinical significance of almost halving the pressure ulcer rate is important. A correlation between body temperature and postoperative pressure ulcers was established.

Transcranial electrical motor evoked potential monitoring for brain tumor resection

OBJECTIVE

This study was designed to examine whether transcranial electrical motor evoked potential (MEP) monitoring is safe, feasible, and valuable for brain tumor surgery.

METHODS

Fifty consecutive patients undergoing brain tumor resection were studied, using nitrous oxide/propofol anesthesia. MEPs were continuously recorded throughout surgery, using a Sentinel 4 evoked potential system (Axon Systems, Inc., Hauppauge, NY). The MEPs were elicited by transcranial electrical stimulation (train of 5; stimulation rate, 0.5-2 Hz; square wave pulse with a time constant of 0.5 ms; stimulation intensity, 40-160 mA) through spiral electrodes placed over the primary motor cortex and were recorded by needle electrodes inserted into the contralateral orbicularis oris, biceps, abductor pollicis brevis, and anterior tibialis muscles. When MEP amplitudes decreased by more than 50%, MEP stimulation was repeated, with increased stimulation intensity, and MEP changes were reported to the surgeon. The motor function of each patient was examined before and after surgery, using a reproducible scale. The relationship between MEP amplitude decreases and worsening motor status was analyzed using linear regression.

RESULTS

Preoperative neurological examinations revealed mild to moderate motor deficits (2/5 to 4/5) for 38% of patients (19 of 50 patients). Most of the patients (96%) exhibited recordable baseline MEPs. Persistent MEP decreases of more than 50% were noted for eight patients (16%) (11 muscles). The MEPs were completely abolished in two patients (three muscles). The degree of postoperative worsening of motor status was correlated with the degree of intraoperative MEP amplitude reduction (r = -0.864; P < 0.001).

CONCLUSION

Persistent intraoperative MEP reductions of more than 50% were associated with postoperative motor deficits. The degree of MEP amplitude reduction was correlated with postoperative worsening of motor status. Transcranial electrical MEP monitoring is feasible, safe, and valuable for brain tumor surgery.

Synthesis of methyl alpha-D-glucopyranosyl-(1-->4)-alpha-D-galactopyranoside and methyl alpha-D-xylo-hex-4-ulopyranosyl-(1-->4)-alpha-D-galactopyranoside

The syntheses of methyl alpha-D-glucopyranosyl-(1-->4)-alpha-D-galactopyranoside (1) and methyl alpha-D-xylo-hex-4-ulopyranosyl-(1-->4)-alpha-D-galactopyranoside (4) are reported. The keto-disaccharide 4 is of interest in our design, synthesis, and study of pectate lyase inhibitors. The key step in the syntheses was the high-yielding, stereospecific formation of methyl 4,6-O-benzylidene-2',3'-di-O-benzyl-alpha-D-glucopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (15), which was accomplished by reacting 2,3-di-O-benzyl-4,6-O-benzylidene-D-glucopyranosyl trichloroacetimidate (10) with methyl 2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (14) in the presence of a catalytic amount of tert-butyldimethylsilyl trifluoromethane sulfonate (TMSOTF). Compound 15 was either hydrogenolyzed to yield disaccharide 1 or treated with NaBH3CN-HCl in 1:1 tetrahydrofuran-ether to yield methyl 2,3,6-tri-O-benzyl-alpha-D-glucopyranosyl-(1-->4)-2,3,6-tri-O-benzyl-alpha-D-galactopyranoside (2). The free 4'-OH of compound 2 was oxidized to a carbonyl group by a Swern oxidation, and the protecting groups were removed by hydrogenolysis to yield keto-disaccharide 4. These synthetic pathways were simple, yet high yielding.

Diffusion MRI in ischemic stroke compared to pathologically verified infarction

BACKGROUND

Diffusion MRI abnormality correlates with pathology in animal ischemic stroke models. A combined retrospective and prospective analysis of consecutive patients over a 3-year period who had a clinical diagnosis of probable new ischemic stroke, underwent diffusion MRI, and were later studied at autopsy was performed.

METHODS

Inclusion criteria for the retrospective analysis were 1) symptom onset within 14 days of presentation, 2) diffusion MRI within 28 days of symptom onset, and 3) autopsy within 16 weeks of symptom onset. Patients with suspected further infarcts between MRI and autopsy were excluded. The locations of all areas of MRI abnormality were identified by a blinded neuroradiologist, and recent infarcts were identified by review of pathologic records and microscopic slides.

RESULTS

Eleven patients were identified who fulfilled inclusion criteria, with 25 discrete pathologic infarcts. Diffusion MRI abnormality corresponded to pathologically verified infarction in 23 cases, was present in two locations where no pathologic infarct was identified, and was absent in two locations where an infarct was present at autopsy. In two cases, despite clinical suspicion of acute ischemic stroke, no MRI abnormality or pathologic infarct was found. The sensitivity and specificity of diffusion MRI were 88.5% (95% CI, 69.9% to 97.6%) and 96.6% (95% CI, 91.5% to 99.1%). Accuracy was 95.1% (95% CI, 90.2% to 98%). Three further patients who died during the course of the retrospective analysis were studied prospectively, and are described separately.

CONCLUSIONS

These findings suggest high accuracy of diffusion MRI for detection of ischemic infarction compared with pathologic examination.

Factors affecting substance abuse treatment completion for women

Substance abuse by women is considered an individual pathology, and the larger social processes of recovery are seldom explored. This research study examined social factors that influenced completion of an outpatient women-centered substance abuse treatment program. The treatment records of a group of 15 women who completed the program were compared with a group who did not complete the program. More completers had previous life successes in the areas of education, job skills, and employment history. Completers also had fewer children, less involvement with child protective services, and lower levels of chaos, a construct that included the presence of two of any of the following in women's lives: child protective services, homelessness, psychiatric diagnosis, or domestic violence. Completion of substance abuse treatment seems more likely for women with personal and social resources. If programs are to be successful, adequate funding must be provided for both assessment and support of the social problems encountered by the most vulnerable women.

Dynamic radioisotope bone imaging as a noninvasive indicator of canine tibial blood flow

The relative values of dynamic and static bone imaging with hydroxymethylenediphosphonate technetium 99m (99mTc HDP) as an indicator of bone blood flow was investigated in the tibia of mature dogs. The dynamic bone scan consisted of 60 1-s images formed after the intravenous injection of 99mTc HDP, and the static bone scan was a 45-min uptake image. Blood flow to the tibia was determined by using radioactively labeled microspheres. Studies were carried out in control dogs, in dogs in which blood flow was increased in one leg with ATP, and in dogs in which blood flow was decreased in one leg with norepinephrine. A significant (p less than 0.001) linear relationship between the dynamic scan values and bone blood flow was found at a wide range of blood flow rates. When blood flow increased by more than 50%, the effects of "diffusion limitation" were seen in the static scans: increase in tracer uptake was disproportionately small for a significant increase in blood flow. There is no method currently available for estimating bone blood flow by a noninvasive technique. The method described here may be useful for providing a semiquantitative measure of bone blood flow. This improved versatility of bone imaging may have a role in the management of osteomyelitis or complicated fractures, or in assessing the viability of vascularized bone grafts.

Robot-assisted microsurgery: a feasibility study in the rat

OBJECTIVE

Telerobotic surgery is a novel technology that can improve a surgeon's manual dexterity as well as the results achieved with microsurgical procedures.

METHODS

A prototype Robot-Assisted MicroSurgery (RAMS) microdexterity enhancement system developed by the Jet Propulsion Laboratory and MicroDexterity Systems, Inc., was tested in 10 rats. Carotid arteriotomies were created and closed using either the RAMS system or conventional microsurgical techniques. The time required, the technical quality (vessel patency and suture line integrity), the error rate, and subjective difficulty were compared.

RESULTS

All procedures were successfully completed using the RAMS system to manipulate the vessel but not to hold the needle or place the sutures. The precision, technical quality, and error rate of telerobotic surgery were similar to those of conventional techniques. However, the use of the RAMS system was associated with a twofold increase in the length of the procedure.

CONCLUSION

Surgery using a microdexterity enhancement system, or RAMS prototype, is feasible. With further development, such as a stereotelevisualization and haptic feedback system, this system could be used for telerobotic surgery in neurosurgical practice.