Implementation of sonopartogram: multicenter feasibility study.

OBJECTIVES: Well-established clinical practice for assessing progress in labor involves routine abdominal palpation and vaginal examination (VE). However, VE is subjective, poorly reproducible and painful for most women. In this study, our aim was to evaluate the feasibility of systematically integrating transabdominal and transperineal ultrasound assessment of fetal position, parasagittal angle of progression (psAOP), head-perineum distance (HPD) and sonographic cervical dilatation (SCD) to monitor the progress of labor in women undergoing induction of labor (IOL). We also aimed to determine if ultrasound can reduce women's pain during such examinations. METHODS: Women were recruited as they presented for IOL in three maternity units. Ultrasound assessments were performed in 100 women between 37 + 0 and 41 + 6 weeks' gestation. A baseline combined transabdominal and transperineal scan was performed, including assessment of fetal biometry, umbilical artery and fetal middle cerebral artery Doppler, amniotic fluid index, fetal spine and occiput positions, psAOP, HPD, SCD and cervical length. Intrapartum scans were performed instead of VE, unless there was a clinical indication to perform a VE, according to protocol. Participants were asked to indicate their level of pain by verbally giving a pain score between 0 and 10 (with 0 representing no pain) during assessment. Repeated measures data were analyzed using mixed-effect models to identify significant factors that affected the relationship between psAOP, HPD, SCD and mode of delivery. RESULTS: A total of 100 women were included in the study. Of these, 20% delivered by Cesarean section, 65% vaginally and 15% by instrumental delivery. There were no adverse fetal or maternal outcomes. A total of 223 intrapartum ultrasound scans were performed in 87 participants (13 women delivered before intrapartum ultrasound was performed), with a median of two scans per participant (interquartile range (IQR), 1-3). Of these, 76 women underwent a total of 151 VEs with a median of one VE per participant (IQR, 0-2), with no significant difference between vaginal- or Cesarean-delivery groups. After excluding those with epidural anesthesia during examination, the median pain score for intrapartum scans was 0 (IQR, 0-1) and for VE it was 3 (IQR, 0-6). Cesarean delivery was significantly associated with a slower rate of change in psAOP, HPD and SCD. CONCLUSIONS: Comprehensive transabdominal and transperineal ultrasound assessment can be used to assess progress in labor and can reduce the level of pain experienced during examination. Ultrasound assessment may be able to replace some transabdominal and vaginal examinations during labor. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Prediction of spontaneous preterm birth and preterm prelabor rupture of membranes using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks.

OBJECTIVES: To determine whether first-trimester biomarkers of placental function can be used to screen for spontaneous preterm birth (sPTB), and to develop prediction models using maternal factors, obstetric history and biomarkers of placental function at 11-13 weeks for the calculation of patient-specific risk for sPTB. METHODS: This was a retrospective secondary analysis of data derived from a prospective cohort study on first-trimester screening for pre-eclampsia in singleton pregnancies attending for routine Down syndrome screening at 11 + 0 to 13 + 6 weeks' gestation at a tertiary obstetric unit between December 2016 and September 2019. A split-sample internal validation method was used to explore and develop prediction models for all sPTB at < 37 weeks and for PTB at < 37 weeks after preterm prelabor rupture of membranes (PPROM) using maternal risk factors, uterine artery Doppler indices, serum placental growth factor (PlGF), pregnancy-associated plasma protein-A (PAPP-A) and ß-human chorionic gonadotropin (ß-hCG). Screening performance was assessed using receiver-operating-characteristics (ROC)-curve analysis, with calculation of the areas under the ROC curves (AUCs). RESULTS: A total of 9298 singleton pregnancies were included in this study. sPTB at < 37 weeks occurred in 362 (3.89%) cases, including 231 (2.48%) cases of PPROM. sPTB at < 34 weeks occurred in 87 (0.94%) cases, including 39 (0.42%) cases of PPROM. Identified maternal risk factors for sPTB at < 37 weeks included chronic hypertension, conception using in-vitro fertilization and history of PTB. Maternal risk factors for PPROM at < 37 weeks included conception using in-vitro fertilization and history of PTB. Median PlGF multiples of the median (MoM) and PAPP-A MoM were significantly reduced in women with sPTB at < 37 weeks, as well as in those who had PPROM, compared to those who delivered at term. Screening by a combination of maternal risk factors, PAPP-A and PlGF achieved better performance in predicting sPTB at < 37 weeks (AUC, 0.630 vs 0.555; detection rate (DR), 24.8% vs 16.6% at a false-positive rate (FPR) of 10%; P ≤ 0.0001) and PPROM at < 37 weeks (AUC, 0.643 vs 0.558; DR, 28.1% vs 17.0% at a FPR of 10%; P ≤ 0.0001) than using maternal risk factors alone. Both models were successfully applied to the internal validation dataset, with AUCs of 0.628 and 0.650, respectively. CONCLUSIONS: We demonstrated that low levels of maternal serum PAPP-A and PlGF in the first trimester are associated with increased risks of sPTB and PPROM at < 37 weeks. However, further research is needed to identify additional biomarkers to improve the screening performance of the combined model that includes maternal risk factors, PAPP-A and PlGF before clinical application. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

[From digital virtual human, three-dimensional visualization to digital intelligence in liver surgery].

Digital intelligent hepatobiliary surgery has evolved over decades.It has experienced an evolution course from digital virtual human technology to the establishment of a quality-controlled and homogeneous three-dimensional visualization system for precision diagnosis and treatment of diseases, from three-dimensional visualization to the clinical transformation of digital intelligent technology and changes in the diagnosis and treatment model, from empirical diagnosis of diseases to the application of deep learning for the intelligent diagnosis and treatment of diseases, from empirical surgery to real-time multi-modal image guidance during surgery, and from the morphological diagnosis of tumors to accurate diagnosis from molecular imaging.During the whole process, only through continuous innovation in research, theory and technology can the "life" of digital intelligent surgery be endowed with new vitality.In the future, the definition of tumor boundary from the molecular and cellular levels and the early diagnosis and treatment of liver tumor through the functional visualization of key molecules will have significant clinical value for changing the prognosis of liver cancer.In addition, in order to realize intelligent navigation for hepatectomy and break through the technical bottleneck, it is of great clinical significance to develop an intelligent robot real-time navigation hepatectomy system with automatic navigation technology, machine learning intelligent planning technology and multimodal image fusion technology.This provides unprecedented opportunities and challenges for the development of digital intelligent hepatobiliary surgery.

[Construction and application of the core technology system of digital intelligent diagnostic and treatment for hepato-biliary-pancreatic diseases].

Digital intelligent diagnostic and treatment technology is a novel technology which is based by combining modern medicine with digitalized and intelligent high-tech to form a multidisciplinary and multi-knowledge domain. This technology plays an important role in areas including precision diagnosis, preoperative planning and surgical navigation. Its core technologies are: (1) quality control research on high-quality CT imaging data acquisition; (2) quality control and homogenization research on three-dimensional (3D) reconstruction; (3) high-quality 3D printed physical models; (4) virtual reality 3D simulation platform; (5) molecular fluorescence imaging to define tumor boundaries; (6) non-rigid registration multi-mode image fusion surgical navigation system; (7) image feature extraction and prediction model establishment. The workflow of this system includes: First, CT data acquisition and 3D visualization of hepatobiliary and pancreatic diseases; followed by individualized vascular assessment, liver volume calculation and surgical planning using the 3D model; then virtual simulation surgery, 3D printing, virtual reality technology and molecular fluorescence imaging accordance to the required specific conditions. Preoperative radiomics are used to predict the risk of complications and long-term follow-up results. Intraoperative multi-modal fusion image navigation and its consistency are evaluated with the findings in actual surgery and preoperative planning. This technology, hopefully, will bring in novel strategies and approaches in the diagnosis and treatment of hepatobiliary and pancreatic diseases.

[Ten years retrospective review of the application of digital medical technology in general surgery in China].

Digital medical technology is a powerful tool which has forcefully promoted the development of general surgery in China. In this article, we reviews the application status of three-dimensional visualization and three-dimensional printing technology in general surgery, introduces the development situation of surgical navigation guided by optical and electromagnetic technology and preliminary attempt to combined with mixed reality applied to complicated hepatectomy, looks ahead the development direction of digital medicine in the era of artificial intelligence and big data on behalf of surgical robot and radiomics. Surgeons should proactively master these advanced techniques and accelerate the innovative development of general surgery in China.

Therapeutic inertia in the management of hyperlipidaemia in type 2 diabetic patients: a cross-sectional study in the primary care setting.

OBJECTIVES: To study the prevalence of therapeutic inertia in lipid management among type 2 diabetic patients in the primary care setting and to explore associated factors. METHODS: This was a cross-sectional study involving type 2 diabetic patients with suboptimal lipid control followed up in all general out-patient clinics of Kowloon Central Cluster in Hong Kong from 1 October 2011 to 30 September 2013. Main outcome measures included prevalence of therapeutic inertia in low-density lipoprotein management among type 2 diabetic patients and its association with patient and physician characteristics. RESULTS: Based on an agreed standard, lipid control was suboptimal in 49.1% (n=9647) of type 2 diabetic patients who attended for a regular annual check-up (n=19 662). Among the sampled 369 type 2 diabetic patients with suboptimal lipid control, therapeutic inertia was found to be present in 244 cases, with a prevalence rate of 66.1%. When the attending doctors' profiles were compared, the mean duration of clinical practice was significantly longer in the therapeutic inertia group than the non-therapeutic inertia group. Doctors without prior training in family medicine were also found to have a higher rate of therapeutic inertia. Patients in the therapeutic inertia group had longer disease duration, a higher co-morbidity rate of cardiovascular disease, and a closer-to-normal low-density lipoprotein level. Logistic regression analysis revealed that lack of family medicine training among doctors was positively associated with the presence of therapeutic inertia whereas patient's low-density lipoprotein level was inversely associated. CONCLUSIONS: Therapeutic inertia was common in the lipid management of patients with type 2 diabetes in a primary care setting. Lack of family medicine training among doctors and patient's low-density lipoprotein level were associated with the presence of therapeutic inertia. Further study of the barriers and strategies to overcome therapeutic inertia is needed to improve patient outcome in this aspect of chronic disease management.

[The clinical advantage of using three dimensional visualization technology in hepatic surgery].

The three-dimensional body visible system is a further development of the three-dimensional CT reconstruction system. It has a lot of merits over the latter system. Clinical application of the three-dimensional body visible system in liver surgery showed the system to have the following merits: (1) The system can support the Couinaud classification of liver anatomy into two hemilivers, four sectors and eight segments. As the system can rotate the liver to any angle and it has the ability to make part or whole of the liver transparent thus making the internal blood vessels and bile ducts visible. Learning liver anatomy and liver surgery becomes easier. (2)The system can clearly localize liver tumors within the liver segment(s). (3)It can help clinicians to decide and to plan different operations on an individual. (4)By carrying out simulation partial hepatectomy using this system, it can help clinicians to estimate the difficulty and the risks involved in different options of liver resection and finally.(5)The system helps clinicians to identify anomalies in hepatic artery, portal vein, hepatic vein and bile duct, thus making the operation safer. In conclusion, this system significantly improves on the conventional three-dimensional CT reconstruction system. It is especially useful for inexperienced liver surgeons.

Absolute Instability near the Band Edge of Traveling-Wave Amplifiers.

Applying the Briggs-Bers "pole-pinch" criterion to the exact transcendental dispersion relation of a dielectric traveling wave tube (TWT), we find that there is no absolute instability regardless of the beam current. We extend this analysis to the circuit band edges of a linear beam TWT by approximating the circuit mode as a hyperbola in the frequency-wave-number (ω-k) plane and consider the weak coupling limit. For an operating mode whose group velocity is in the same direction as the beam mode, we find that the lower band edge is not subjected to absolute instability. At the upper band edge, we find a threshold beam current beyond which absolute instability is excited. The nonexistence of absolute instability in a linear beam TWT and the existence in a gyrotron TWT, both at the lower band edge, is contrasted. The general study given here is applicable to some contemporary TWTs such as metamaterial-based and advanced Smith-Purcell TWTs.

Novel scaling laws for the Langmuir-Blodgett solutions in cylindrical and spherical diodes.

It is found that the Langmuir-Blodgett solutions for the space charge limited current density, for both cylindrical and spherical diodes, may be approximated by Japp=(4/9)ε0sqrt[(2e/m)](Ec3/2/sqrt[D]) over a wide range of parameters, where Ec is the surface electric field on the cathode of the vacuum diode and D is the anode-cathode spacing. This dependence is valid whether Ra/Rc is greater than or less than unity, where Ra and Rc are, respectively, the anode and cathode radius. Minor empirical corrections to the above scaling yield fitting formulas that are accurate to within 5% for 3×10(-5)

Multipactor experiments on an S-band coaxial test cell.

Radio frequency vacuum electronics are prone to multipactor discharges. These electron discharges, driven by secondary electron emission, can disrupt and damage devices and are particularly important in satellite communication systems. We present results from a new S-band coaxial multipactor test cell which demonstrates scaling to much higher frequencies (3.05 GHz) than previous coaxial experiments (10-150 MHz). The multipactor breakdown threshold has been found to agree very well with our earlier simulated predictions. The significant effect from multipactor self-conditioning has also been demonstrated and characterized. Future experiments will use this test cell to investigate various multipactor mitigation strategies.

Rapid aneuploidy screening with fluorescence in-situ hybridisation: is it a sufficiently robust stand-alone test for prenatal diagnosis?

OBJECTIVES: To assess the clinical utility of fluorescence in-situ hybridisation with chromosomes 13, 18, 21, X and Y as a stand-alone test in detecting chromosomal abnormalities, and the types of chromosomal abnormalities missed. DESIGN: Retrospective analysis. SETTING: A restructured Government hospital in Singapore and an academic hospital in the United States. PARTICIPANTS: Cytogenetic data of prenatal specimens and results of fluorescence in-situ hybridisation of 5883 patients performed between January 2000 and August 2007 were reviewed. RESULTS: Fluorescence in-situ hybridisation detected 558 (9.5%) patients with chromosomal abnormalities. Abnormal ultrasounds (70%) and maternal serum screens (21%) were the most indicative of chromosomal abnormalities. When comparing fluorescence in-situ hybridisation data with karyotype results for the five chromosomes of interest, the sensitivity and specificity were 99.3% and 99.9%, respectively. When comparing fluorescence in-situ hybridisation data with karyotype results for all chromosomes, the sensitivity decreased to 86.8%, whereas the specificity remained at 99.9%. Of 643 cases with karyotype abnormalities, 85 were fluorescence in-situ hybridisation-negative (false negative rate, 13.2%), which included structural rearrangements, chromosome mosaicism, and other trisomies. Despite abnormal ultrasound indications, fluorescence in-situ hybridisation missed 32 cases which included structural rearrangements, mosaicisms, and other trisomies. CONCLUSION: This study does not support fluorescence in-situ hybridisation as a stand-alone test. Institutions supporting fluorescence in-situ hybridisation as a stand-alone test must seriously consider the risks of a missed diagnosis.

Metal-oxide-junction, triple point cathodes in a relativistic magnetron.

Triple point, defined as the junction of metal, dielectric, and vacuum, is the location where electron emission is favored in the presence of a sufficiently strong electric field. To exploit triple point emission, metal-oxide-junction (MOJ) cathodes consisting of dielectric "islands" over stainless steel substrates have been fabricated. The two dielectrics used are hafnium oxide (HfO(x)) for its high dielectric constant and magnesium oxide (MgO) for its high secondary electron emission coefficient. The coatings are deposited by ablation-plasma-ion lithography using a KrF laser (0-600 mJ at 248 nm) and fluence ranging from 3 to 40 J/cm(2). Composition and morphology of deposited films are analyzed by scanning electron microscopy coupled with x-ray energy dispersive spectroscopy, as well as x-ray diffraction. Cathodes are tested on the Michigan Electron Long-Beam Accelerator with a relativistic magnetron, at parameters V=-300 kV, I=1-15 kA, and pulse lengths of 0.3-0.5 micros. Six variations of the MOJ cathode are tested, and are compared against five baseline cases. It is found that particulate formed during the ablation process improves the electron emission properties of the cathodes by forming additional triple points. Due to extensive electron back bombardment during magnetron operation, secondary electron emission also may play a significant role. Cathodes exhibit increases in current densities of up to 80 A/cm(2), and up to 15% improvement in current start up time, as compared to polished stainless steel cathodes.

effect of OATP1B transporter inhibition on the pharmacokinetics of atorvastatin in healthy volunteers.

The inhibition of hepatic uptake transporters, such as OATP1B1, on the pharmacokinetics of atorvastatin is unknown. Here, we investigate the effect of a model hepatic transporter inhibitor, rifampin, on the kinetics of atorvastatin and its metabolites in humans. The inhibitory effect of a single rifampin dose on atorvastatin kinetics was studied in 11 healthy volunteers in a randomized, crossover study. Each subject received two 40-mg doses of atorvastatin, one on study day 1 and one on study day 8, separated by 1 week. One intravenous 30-min infusion of 600 mg rifampin was administered to each subject on either study day 1 or study day 8. Plasma concentrations of atorvastatin and metabolites were above the limits of quantitation for up to 24 h after dosing. Rifampin significantly increased the total area under the plasma concentration-time curve (AUC) of atorvastatin acid by 6.8+/-2.4-fold and that of 2-hydroxy-atorvastatin acid and 4-hydroxy-atorvastatin acid by 6.8+/-2.5- and 3.9+/-2.4-fold, respectively. The AUC values of the lactone forms of atorvastatin, 2-hydroxy-atorvastatin and 4-hydroxy-atorvastatin, were also significantly increased, but to a lower extent. An intravenous dose of rifampin substantially increased the plasma concentrations of atorvastatin and its acid and lactone metabolites. The data confirm that OATP1B transporters represent the major hepatic uptake systems for atorvastatin and its active metabolites. Inhibition of hepatic uptake may have consequences for efficacy and toxicity of drugs like atorvastatin that are mainly eliminated by the hepatobiliary system.

Implications of a simple mathematical model to cancer cell population dynamics.

Recent research in cancer progression and treatment indicates that many forms of cancer arise from the development of a small subpopulation of abnormal cancer stem cells (CSCs) that promote cancer growth and spread. Many potential treatments preferentially interact with cells at certain stages of the cell cycle by either selective killing or halting the cell cycle, such as intense, nanosecond-duration pulsed electric fields (nsPEFs). Simple mathematical models of unfed cancer cell populations at the plateau of their growth characteristics may estimate the long-term consequences of these treatments on proliferating and quiescent cell populations. Applying such a model with no transition from the quiescent to proliferating state shows that it is possible for the proliferating cell population to fall below 1 if the quiescent cell population obtains a sufficient competitive advantage with respect to nutrient consumption and/or survival rate. Introducing small, realistic transition rates did not appreciably alter short-term or long-term population behaviour, indicating that the predicted small cell population behaviour (< 1 cell) is not an artefact of the simpler model. Experimental observations of nsPEF-induced effects on the cell cycle suggest that such a model may serve as a first step in assessing the viability of a given cancer treatment in vitro prior to clinical application.

Ultrafast strong-field photoelectron emission from biased metal surfaces: exact solution to time-dependent Schrödinger Equation.

Laser-driven ultrafast electron emission offers the possibility of manipulation and control of coherent electron motion in ultrashort spatiotemporal scales. Here, an analytical solution is constructed for the highly nonlinear electron emission from a dc biased metal surface illuminated by a single frequency laser, by solving the time-dependent Schrödinger equation exactly. The solution is valid for arbitrary combinations of dc electric field, laser electric field, laser frequency, metal work function and Fermi level. Various emission mechanisms, such as multiphoton absorption or emission, optical or dc field emission, are all included in this single formulation. The transition between different emission processes is analyzed in detail. The time-dependent emission current reveals that intense current modulation may be possible even with a low intensity laser, by merely increasing the applied dc bias. The results provide insights into the electron pulse generation and manipulation for many novel applications based on ultrafast laser-induced electron emission.

Thomson scattering and ponderomotive intermodulation within standing laser beat waves in plasma.

Electrons in a standing electromagnetic wave--an optical lattice--tend to oscillate due to the quiver and ponderomotive potentials. For sufficiently intense laser fields (Ilamda2 approximately < or = 5 x 10(17) W cm(-2) microm2) and in plasmas with sufficiently low electron densities (n approximately < or = 10(18) cm(-3)), these oscillations can occur faster than the plasma can respond. This paper shows that these oscillations result in Thomson scattering of light at both the laser and ponderomotive bounce frequencies and their harmonics as well as at mixtures of these frequencies. We term this mixing ponderomotive intermodulation. Here, the case of counterpropagating laser beams creating a one-dimensional (1D) optical lattice is analyzed. The near-equilibrium electron orbits and subsequent Thomson scattering patterns are computed in the single-particle limit. Scaling laws are derived to quantify the range of validity of this approach. Finally, collective plasma and laser focusing effects are included by using particle-in-cell (PIC) techniques. This effect resulting in light-frequency conversion has applications both as an infrared light source and as a means to diagnose high laser intensities inside dense plasmas.

Does the environmental background (intensive v. outdoor systems) influence the behaviour of piglets at weaning?

Under intensive pig husbandry, outdoor systems offer a more complex physical and social environment compared with indoor systems (farrowing sheds). As the rearing environment affects behavioural development, it can, therefore, influence behavioural responses of pigs to stressful environments in later stages of production. We tested how the rearing environment influenced behavioural responses to a novel arena test in piglets on the day that they were weaned and mixed into large groups. We recorded video footage and compared the behavioural responses of 30 outdoor-raised and 30 farrowing shed-raised piglets tested in an experimental arena and sequentially exposed to four challenges (each for 5 min) on the day of weaning. Quantitative and qualitative behavioural measures were recorded using time budgets and scoring demeanour or 'qualitative behavioural expression' (using Qualitative Behavioural Assessment (QBA)). When held in isolation (challenge 1), both groups were scored as more 'scared/worried', while outdoor-raised piglets spent more time eating and jumping against the arena walls. Both groups interacted with a plastic ball (challenge 2: exposure to a novel object) during which they were scored as more 'playful/curious' than other challenges. When a food bowl was introduced (challenge 3), farrowing shed-raised piglets were more interested in playing with the food bowl itself, whereas outdoor-raised piglets spent more time eating the feed. Finally, there were no significant differences in social behaviour (challenge 4: introduction of another piglet) between the two groups in terms of the latency to contact each other, amount of time recorded engaged in aggressive/non-aggressive social interactions or QBA scores. Although piglets spent 30% of their time interacting with the other piglet, and half of this time (47%) was engaged in negative interactions (pushing, biting), the levels of aggression were not different between the two groups. Overall, outdoor-raised piglets ate more and were scored as more 'calm/passive', whereas farrowing shed-raised piglets spent more time investigating their environment and were scored as more 'playful/inquisitive'. In conclusion, we did not find differences in behaviour between outdoor-raised and farrowing shed-raised piglets that would highlight welfare issues. The differences found in this study may reflect conflicting affective states, with responses to confinement, neophobia and motivation for exploration evident.

Technique for fabrication of ultrathin foils in cylindrical geometry for liner-plasma implosion experiments with sub-megaampere currents.

In this work, we describe a technique for fabricating ultrathin foils in cylindrical geometry for liner-plasma implosion experiments using sub-MA currents. Liners are formed by wrapping a 400 nm, rectangular strip of aluminum foil around a dumbbell-shaped support structure with a non-conducting center rod, so that the liner dimensions are 1 cm in height, 6.55 mm in diameter, and 400 nm in thickness. The liner-plasmas are imploded by discharging ∼600 kA with ∼200 ns rise time using a 1 MA linear transformer driver, and the resulting implosions are imaged four times per shot using laser-shadowgraphy at 532 nm. This technique enables the study of plasma implosion physics, including the magneto Rayleigh-Taylor, sausage, and kink instabilities on initially solid, imploding metallic liners with university-scale pulsed power machines.

Capillary electrophoresis of single cells: observation of two compartments of neurotransmitter vesicles.

Capillary electrophoresis has been used to directly identify and measure the neurotransmitter, dopamine, in two vesicular compartments in a single nerve cell of Planorbis corneus. Dopamine in the cytoplasm and in easily released transmitter vesicles was separated from dopamine in what are apparently non-functional storage vesicles. In this method, the two peaks in the electropherogram attributed to dopamine were differentiated based on cell lyse time in a non-physiological buffer. The measurements presented here suggest that of the total dopamine present in the cell: 24% is in the cytoplasmic and easily released compartments and 76% is more centrally located, perhaps in a reserve compartment, in the cell. This methodology provides the means to determine molecular species in subcellular compartments and should allow kinetic parameters associated with membrane lysing to be evaluated at single nerve cells.