Enhancing violations of Leggett-Garg inequalities in nonequilibrium correlated many-body systems by interactions and decoherence

We identify different schemes to enhance the violation of Leggett-Garg inequalities in open many-body systems. Considering a nonequilibrium archetypical setup of quantum transport, we show that particle interactions control the direction and amplitude of maximal violation, and that in the strongly-interacting and strongly-driven regime bulk dephasing enhances the violation. Through an analytical study of a minimal model we unravel the basic ingredients to explain this decoherence-enhanced quantumness, illustrating that such an effect emerges in a wide variety of systems.

Spontaneous Separation in Idiopathic Vitreomacular Traction Syndrome Associated with Contralateral Full-Thickness Macular Hole

Purpose

Vitreomacular traction syndrome (VMTS) and full-thickness macular hole are two different well-known entities that on follow-up may be subjected to clinical modifications. Precisely, a spontaneous separation of idiopathic VMTS occurred in three eyes of three patients relieving in addition traction of the posterior hyaloid that had led also to a focal macular pigment epithelium detachment (RPE). An association to a full-thickness macular hole was observed in the contralateral eye of one of the patients.

Methods

This is a retrospective study of three patients evaluated with fluorescein angiography and documented with optical coherence tomography using the Stratus (OCT) model 3000, with scans analysis and protocols analysis, measuring the size and shape of vitreomacular adhesions, macular thickness changes before and after the spontaneous separation of the fractional posterior hyaloid adhesion. In addition, the vitreous was evaluated with contact lens slit lamp biomicroscopy and ultrasound. The associated contralateral macular hole in one of the patients was surgically treated.

Results

Two of the three eyes with spontaneous separation of the VMTS recovered 20/25 central visual acuity; the other eye maintained the initial 20/50 visual acuity. The treated macular hole recovered 20/100 corrected visual acuity.

Conclusions

Spontaneous separation of posterior hyaloid is a possible outcome during follow-up of idiopathic VMTS that can be well evaluated and documented with OCT while macular fluorescein angiography may be silent in cases like these presently reported. Central vision recovery can be excellent following the spontaneous separation, which releases anterior-posterior traction including on the retinal pigment epithelium and decreases macular thickness as measured with OCT. Therefore, regarding management, the indication for vitrectomy should be delayed awaiting the spontaneous release of vitreomacular traction in 4 to 6 months. The association between idiopathic VMTS in one eye and full-thickness macular hole in the opposite eye of one patient is an important pathophysiologic consideration.

[Amebiasis of the central nervous system: report of six cases in Peru]

Six cases of amoebic encephalitis admitted to the National Institute of Neoplastic Diseases between the years 1994-2010 in Peru are reported. These cases were admitted for clinical suspicion of malignant primary brain tumor and one orbital-nasal sarcoma. All cases came from coastal regions; three were less than 24 years of age and four were male. The most common symptoms were headache and seizures. Three cases had more than one brain lesion. Stereotactic biopsy was performed in three patients and the differential pathological diagnosis in two cases was glioma of high and low grade. It was possible to confirm the diagnosis using molecular techniques in paraffin-embedded samples in three cases. All patients died within 15 days of admission to the institution. Amoebic encephalitis may be erroneously interpreted as a cerebral neoplasm, causing delay in the management of the infection.

Synchronous GH- and prolactin-secreting pituitary adenomas

Pituitary adenomas are usually solitary lesions. Rarely, patients may present with two distinct pituitary tumors. We report a case of synchronous secretory pituitary adenomas in a woman who initially presented with elevated prolactin levels. She was initially treated with cabergoline, but, after many years, she began developing symptoms consistent with acromegaly. Imaging revealed two distinct tumors within the pituitary gland. Endocrinological investigation confirmed acromegaly. At the time of surgery, two separate tumors were identified and resected. Pathological analysis demonstrated one tumor as a prolactinoma, and the other tumor as a GH-secreting adenoma. Postoperatively, her GH and IGF1 levels normalized, while the prolactin level remained slightly above normal. This case highlights that GH and prolactin level elevation is not always from co-secretion by the same adenoma.

New dynamical scaling universality for quantum networks across adiabatic quantum phase transitions

We reveal universal dynamical scaling behavior across adiabatic quantum phase transitions in networks ranging from traditional spatial systems (Ising model) to fully connected ones (Dicke and Lipkin-Meshkov-Glick models). Our findings, which lie beyond traditional critical exponent analysis and adiabatic perturbation approximations, are applicable even where excitations have not yet stabilized and, hence, provide a time-resolved understanding of quantum phase transitions encompassing a wide range of adiabatic regimes. We show explicitly that even though two systems may traditionally belong to the same universality class, they can have very different adiabatic evolutions. This implies that more stringent conditions need to be imposed than at present, both for quantum simulations where one system is used to simulate the other and for adiabatic quantum computing schemes.

Confirming the validity of the CONUT system for early detection and monitoring of clinical undernutrition: comparison with two logistic regression models developed using SGA as the gold standard

AIM

To ratify previous validations of the CONUT nutritional screening tool by the development of two probabilistic models using the parameters included in the CONUT, to see if the CONUT´s effectiveness could be improved.

METHODS

It is a two step prospective study. In Step 1, 101 patients were randomly selected, and SGA and CONUT was made. With data obtained an unconditional logistic regression model was developed, and two variants of CONUT were constructed: Model 1 was made by a method of logistic regression. Model 2 was made by dividing the probabilities of undernutrition obtained in model 1 in seven regular intervals. In step 2, 60 patients were selected and underwent the SGA, the original CONUT and the new models developed. The diagnostic efficacy of the original CONUT and the new models was tested by means of ROC curves. Both samples 1 and 2 were put together to measure the agreement degree between the original CONUT and SGA, and diagnostic efficacy parameters were calculated.

RESULTS

No statistically significant differences were found between sample 1 and 2, regarding age, sex and medical/surgical distribution and undernutrition rates were similar (over 40%). The AUC for the ROC curves were 0.862 for the original CONUT, and 0.839 and 0.874, for model 1 and 2 respectively. The kappa index for the CONUT and SGA was 0.680.

CONCLUSIONS

The CONUT, with the original scores assigned by the authors is equally good than mathematical models and thus is a valuable tool, highly useful and efficient for the purpose of Clinical Undernutrition screening.

Confirming the validity of the CONUT system for early detection and monitoring of clinical undernutrition: comparison with two logistic regression models developed using SGA as the gold standard

AIM

To ratify previous validations of the CONUT nutritional screening tool by the development of two probabilistic models using the parameters included in the CONUT, to see if the CONUT´s effectiveness could be improved.

METHODS

It is a two step prospective study. In Step 1, 101 patients were randomly selected, and SGA and CONUT was made. With data obtained an unconditional logistic regression model was developed, and two variants of CONUT were constructed: Model 1 was made by a method of logistic regression. Model 2 was made by dividing the probabilities of undernutrition obtained in model 1 in seven regular intervals. In step 2, 60 patients were selected and underwent the SGA, the original CONUT and the new models developed. The diagnostic efficacy of the original CONUT and the new models was tested by means of ROC curves. Both samples 1 and 2 were put together to measure the agreement degree between the original CONUT and SGA, and diagnostic efficacy parameters were calculated.

RESULTS

No statistically significant differences were found between sample 1 and 2, regarding age, sex and medical/surgical distribution and undernutrition rates were similar (over 40%). The AUC for the ROC curves were 0.862 for the original CONUT, and 0.839 and 0.874, for model 1 and 2 respectively. The kappa index for the CONUT and SGA was 0.680.

CONCLUSIONS

The CONUT, with the original scores assigned by the authors is equally good than mathematical models and thus is a valuable tool, highly useful and efficient for the purpose of Clinical Undernutrition screening.

Quantum-correlated two-photon transitions to excitons in semiconductor quantum wells

The dependence of the excitonic two-photon absorption on the quantum correlations (entanglement) of exciting biphotons by a semiconductor quantum well is studied. We show that entangled photon absorption can display very unusual features depending on space-time-polarization biphoton parameters and absorber density of states for both bound exciton states as well as for unbound electron-hole pairs. We report on the connection between biphoton entanglement, as quantified by the Schmidt number, and absorption by a semiconductor quantum well. Comparison between frequency-anti-correlated, unentangled and frequency-correlated biphoton absorption is addressed. We found that exciton oscillator strengths are highly increased when photons arrive almost simultaneously in an entangled state. Two-photon-absorption becomes a highly sensitive probe of photon quantum correlations when narrow semiconductor quantum wells are used as two-photon absorbers.

The use of biochemical and immunological parameters in nutritional screening and assessment

OBJECTIVE

To evaluate the relationship between serum albumin, total cholesterol and total lymphocyte count with two nutritional assessment methods, to verify if their use is justified in nutritional screening tools.

METHODS

101 patients admitted to medical/surgical wards underwent the SGA and the Full Nutritional Assessment (FNA). Blood test which included serum albumin, total cholesterol and total lymphocyte count (TLC), were made. Percentage of weight loss and BMI were calculated. An Anova test was done to measure the differences in the mean levels of the three parameters for the nutritional status evaluated by SGA and FNA. The probability of a patient being malnourished in the four ranges established for each parameter was calculated, as well as the relationship between the ranges and the percentage of weight loss and BMI. Sensitivity and specificity were calculated and the corresponding ROC curves, using SGA as gold standard.

RESULTS

Prevalence of undernutrition is 43.6% and 44.6% for SGA and FNA respectively. Mean levels of the three parameters decrease as the undernutrition degree increases (p < 0.005 for all cases). The probability of a patient being malnourished gets higher as parameter lowers (p = 0.000 for all cases). Total cholesterol shows a relationship with BMI < 18.5 and presence/absence of weight loss (p = 0.074 and p = 0.002 respectively). The area under ROC curves are albumin (0.823), cholesterol (0.790) and TLC (0.758) respectively.

CONCLUSIONS

The analytical parameters analyzed show a statistically significant relationship with the nutritional status. Therefore, they are suitable for use in nutritional screening.

Development of a TiO2 modified optical fiber electrode and its incorporation into a photoelectrochemical reactor for wastewater treatment

Electrochemical advanced oxidation processes (EAOPs) are used to chemically burn non biodegradable complex organic compounds that are present in polluted effluents. A common approach involves the use of TiO2 semiconductor substrates as either photocatalytic or photoelectrocatalytic materials in reactors that produce a powerful oxidant (hydroxyl radical) that reacts with pollutant species. In this context, the purpose of this work is to develop a new TiO2 based photoanode using an optic fiber support. The novel arrangement of a TiO2 layer positioned on top of a surface modified optical fiber substrate, allowed the construction of a photoelectrochemical reactor that works on the basis of an internally illuminated approach. In this way, a semi-conductive optical fiber modified surface was prepared using 30 microm thickness SnO2:Sb films on which the photoactive TiO2 layer was electrophoretically deposited. UV light transmission experiments were conducted to evaluate the transmittance along the optical fiber covered with SnO2:Sb and TiO2 showing that 43% of UV light reached the optical fiber tip. With different illumination configurations (external or internal), it was possible to get an increase in the amount of photo-generated H(2)O(2) close to 50% as compared to different types of TiO2 films. Finally, the electro-Fenton photoelectrocatalytic Oxidation process studied in this work was able to achieve total color removal of Azo orange II dye (15 mg L(-1)) and a 57% removal of total organic carbon (TOC) within 60 min of degradation time.

Fast and stable recording of birefringence and holographic gratings in an azo-polymethacrylate using a single nanosecond light pulse

Pulsed light-induced recording in azobenzene polymers has recently been studied due to its potential use in optical storage applications. In this paper we study the photoinduced birefringence (Deltan) and holographic grating recording in an azobenzene side chain liquid-crystalline polymethacrylate irradiating with a single 4 ns light pulse at 532 nm. For some irradiation conditions, Deltan grows in less than 50 ns reaching an essentially stable value of about 10(-2). Holographic gratings have been registered using intensity and polarization patterns. Fast response and stability, similar to those of Deltan, was observed in the holographic recording process. Both light-induced anisotropy and relief contributions have been found in the case of gratings recorded using intensity patterns, relief being the dominant contribution at high recording energies. Polarization gratings have been recorded using two orthogonally circularly polarized beams. The resultant gratings showed stable efficiencies up to 0.8% (measured at 633 nm in 1-mum-thick films) and no measurable relief was observed.

[Phosphotyrosine phosphatase SHP-1, somatostatin and prostate cancer]

We review the mechanisms involved in prostatic growth based on androgens and product of neuroendocrine secretion, with special reference to the role of somatostatin (SS) in the inhibition of neoplastic growth. Our contributions in the field confirm the antiproliferative effect of SS on the prostate is mediated by phosphotyrosine phosphatase SHP-1, that is present in human prostate. This enzyme plays a role in the control of prostatic cell proliferation and in the progression of prostate cancer. Besides, we consider its presence may determine the therapeutic potential of SS in the control of prostate cancer.

Engineering an artificial nerve graft for the repair of severe nerve injuries

Nerve repair with tubes has a limit to regeneration depending upon the length of the gap. The characteristics of the guide, in terms of permeability, durability and adhesiveness, also influence regeneration. Considering the importance of the cellular component in regeneration, the development of artificial grafts, composed of a biocompatible nerve guide filled with a neurotropic matrix and seeded with Schwann cells (SCs), is an interesting option to enhance nerve regeneration and provide an alternative to the classical autologous nerve graft. We evaluated the ability of SCs transplanted into a nerve guide to improve regeneration after sciatic nerve resection, leaving a 6-mm gap, in the mouse. Syngeneic, isogeneic and autologous SCs were suspended in Matrigel and seeded in resorbable guides, and compared to acellular guides and to nerve autografts. The immunogenicity of the transplanted SCs clearly influenced the outcome. Transplants of autologous SCs resulted in only slightly lower levels of reinnervation than autografts, but higher recovery and number of regenerated axons than transplants of isologous and syngeneic SCs, and than acellular guides. Thus, by combined developments on nerve guides, extracellular matrix components and cell transplantation, an artificial graft has been designed that allows axonal regeneration across long gaps to levels comparable with an autograft.

Restrictions on the coherence of the ultrafast optical emission from an electron-hole-pair condensate

We report on the transfer of coherence from a quantum-well electron-hole condensate to the light it emits. As a function of density, the coherence of the electron-hole-pair system evolves from being full for the low-density Bose-Einstein condensate to a chaotic behavior for a high-density BCS-like state. This degree of coherence is transferred to the light emitted in a damped oscillatory way in the ultrafast regime. Additionally, the photon field exhibits squeezing properties during the transfer time. Our results suggest a new type of ultrafast experiments for detecting electron-hole-pair condensation.

[Identification of doctors with high pharmaceutical expenditure]

OBJECTIVE

[corrected] To identify doctors with high pharmaceutical expenditure through multiple regression of variables not exclusively dependent on the doctor's decision. To compare the agreement with the method of the Spanish national health servicem which only considered the percentage of pensioners of the doctor's list.

METHODS

Cross-sectional, retrospective, descriptive study of the pharmaceutical expenditure of 220 general practitioners in the health district of Toledo (Spain) in 1999. The following variables were collected: pharmaceutical expenditure for policy-holder/month (PEP-H); age; sex; habitat; size of the list; percentage of pensioners; frequency of attendance (consults/policy-holder-year) and workload (consultations per day). A multiple regression model with backwards elimination was constructed, taking like PEP-H as the dependent variable and the remaining as the independent variables. The resultant equation enabled calculation of the expected PEP-H for each doctor and the deviation of their real expenditure ofrom the expected. Doctors were considered to have high pharmaceutical expenditure when the deviation was more than the mean plus 1 standard deviation of this distribution.

RESULTS

The mean PEP-H was 2,584.4 pesetas. Differences were found (F = 11.665; p < 0.005) in PEP-H per habitat (2,723.2 in rural, 2,521.4 in semi urban and 2,168.2 in urban). A significant correlation was found (p < 0.005) between PEP-H and percentage of pensioners (r = 0.728) and frequency of attendance (r = 0.607). Our final model included percentage of pensioners, frequency of attendance, and age (F = 102.33; p < 0.005; r = 0.767; r² = 0.588; β = 206.05; β₁ = 48.27; β₂ = 61.26; β₃ = 9.55). This model were identified 25 DHPC. With the INSALUD model the identification were of 31. The Kappa index showed that agreement between both methods was 0.706 (SE 0.056) and simple disagreement was found in the classification of 24 doctors (10.9%).

CONCLUSIONS

Frequency of attendance and the percentage of pensioners on doctors' lists are iclosely related to PEP-H. The indicator currently used by the Spanish national health system to identify doctors with high pharmaceutical expenditure could be improved if other variables, such as frenquency of attendance and the doctors' age, were taken into account. The adoption of this method would make budget allocation more impartial and fair.

TNF-alpha dependent production of inducible nitric oxide is involved in PGE(1) protection against acute liver injury

BACKGROUND

Tumour necrosis factor alpha (TNF-alpha) and nitric oxide modulate damage in several experimental models of liver injury. We have previously shown that protection against D-galactosamine (D-GalN) induced liver injury by prostaglandin E(1) (PGE(1)) was accompanied by an increase in TNF-alpha and nitrite/nitrate in serum.

AIMS

The aim of the present study was to evaluate the role of TNF-alpha and nitric oxide during protection by PGE(1) of liver damage induced by D-GalN.

METHODS

Liver injury was induced in male Wistar rats by intraperitoneal injection of 1 g/kg of D-GalN. PGE(1) was administered 30 minutes before D-GalN. Inducible nitric oxide synthase (iNOS) was inhibited by methylisothiourea (MT), and TNF-alpha concentration in serum was lowered by administration of anti-TNF-alpha antibodies. Liver injury was evaluated by alanine aminotransferase activity in serum, and histological examination and DNA fragmentation in liver. TNF-alpha and nitrite/nitrate concentrations were determined in serum. Expression of TNF-alpha and iNOS was also assessed in liver sections.

RESULTS

PGE(1) decreased liver injury and increased TNF-alpha and nitrite/nitrate concentrations in serum of rats treated with D-GalN. PGE(1) protection was related to enhanced expression of TNF-alpha and iNOS in hepatocytes. Administration of anti-TNF-alpha antibodies or MT blocked the protection by PGE(1) of liver injury induced by D-GalN.

CONCLUSIONS

This study suggests that prior administration of PGE(1) to D-GalN treated animals enhanced expression of TNF-alpha and iNOS in hepatocytes, and that this was causally related to protection by PGE(1) against D-GalN induced liver injury.

Stimulation and recording from regenerated peripheral nerves through polyimide sieve electrodes

This paper describes the use of a new polyimide sieve electrode as a chronic neural interface to stimulate and record signals from regenerated peripheral nerves. Flexible thin polyimide electrodes were placed in silicone chambers and implanted between the severed ends of the sciatic nerve in rats. The sieve part of the interface has 281 round via holes of 40 microns diameter, with seven integrated recording-stimulating electrodes arranged around via holes. Axonal regeneration through the via holes was demonstrated by histological and physiological methods over a two to six month post-implantation period in all the rats. The regenerated nerves were organized in fascicles corresponding to the grid pattern of the via holes. Longitudinal sections showed myelinated fibers, with normal appearance and well developed myelin sheath, crossing the via holes. Stimulation of the regenerated nerve through the polyimide electrode evoked distal muscle and nerve responses similar in amplitude to those evoked by nerve stimulation with hook metal electrodes. The polyimide electrodes were useful for recording nerve action potentials in response to electrical stimulation of the distal regenerated nerve, and in response to functional sensory stimulation of several modalities.

Peripheral nerve regeneration through bioresorbable and durable nerve guides

We compared reinnervation of target organs after sciatic nerve resection and repair by tubulization with biodurable tubes of silicone and teflon, or bioresorbable nerve guides of collagen and poly(L-lactide-co-6-caprolactone) (PLC) leaving a 6 mm gap in different groups of mice. All tubes were of 1 mm inside diameter and thin-walled (50 to 250 microm). Functional reinnervation was assessed by noninvasive methods to determine recovery of sweating, sensory and motor functions in the hindpaw repeatedly during 5 months postoperation. PLC guides allowed faster and higher levels of reinnervation for the four functions tested than collagen and silicone tubes, while teflon tubes gave the lowest levels of recovery. Regenerative reinnervation by thin nociceptive and sudomotor fibers was higher than by large sensory and alphamotor fibers in all groups. Resorbable tubes promoted regeneration in a higher proportion of mice than durable tubes. In cases with effective regeneration the nerve cable was multifascicular, with mild to moderate mononuclear cell infiltrates and a thin newly formed perineurium. The number of myelinated fibers was higher in PLC and silicone tubes than in collagen and teflon tubes. There was only minimal inflammatory reaction within the remnants of collagen tubes, but not in the other materials. PLC tubes of slow reabsorption rate seem useful for repairing long gaps in injured nerves.

Expansion of adult Schwann cells from mouse predegenerated peripheral nerves

We present an effective technique for culture and expansion of Schwann cells (SC) from adult peripheral nerves. Cultures from adult mouse sciatic nerves (one to six nerves per culture) in defined medium showed markedly higher purity and density of SC when the nerve was predegenerated in vivo for 7 days than when it was harvested fresh. SC from degenerated nerves were then cultured in defined media conditioned by primary cultures of adult SC. The best results were obtained with a conditioned medium supplemented with 1% fetal calf serum. In these conditions the purity of SC was about 90% and the density about 190 cell/mm(2) by 7-10 days in vitro. These findings indicate that adult SC can be expanded from small preinjured nerve fragments in a short time period to provide a source of SC for autologous cellular transplants.

Polyimide cuff electrodes for peripheral nerve stimulation

This paper describes a new tripolar spiral cuff electrode, composed of a thin (10 microm) and flexible polyimide insulating carrier and three circumneural platinum electrodes, suitable for stimulation of peripheral nerves. The cuffs were implanted around the sciatic nerve of two groups of ten rats each, one in which the polyimide ribbon was attached to a plastic connector to characterize the in vivo stimulating properties of the electrode, and one without a connector for testing possible mechanical nerve damage by means of functional and histological methods. The polyimide cuff electrodes induced only a very mild foreign body reaction and did not change the nerve shape over a 2-6 month implantation period. There were no changes in the motor and sensory nerve conduction tests, nociceptive responses and walking track pattern over follow-up, and no morphological evidence of axonal loss or demyelination, except in one case with partial demyelination of some large fibers after 6 months. By delivering single electrical pulses through the cuff electrodes graded recruitment curves of alpha-motor nerve fibers were obtained. Recruitment of all motor units was achieved with a mean charge density lower than 4 microC/cm(2) for a pulse width of 50 micros at the time of implantation as well as 45 days thereafter. These data indicate that the polyimide cuff electrode is a stable stimulating device, with physical properties and dimensions that avoid nerve compression or activity-induced axonal damage.

Pinus pollen in the atmosphere of Vigo and its relationship to meteorological factors

The Pinus genus has an elevated pollen production and an anemophilous nature. Although considered to be hypoallergenic, numerous cases of allergies caused by Pinus pollen have been cited and different authors believe that its allergenicity should be studied in more depth. In the city of Vigo several patients have tested positive for Pinus pollen extracts in skin tests, some of them being mono-sensitive to such pollens. In order to ascertain the behaviour of Pinus pollen and its correlation to the main meteorological factors, we carried out an aerobiological study in the city of Vigo from 1995 to 1998 by using a Hirst active-impact volumetric sporetrap, model Lanzoni VPPS 2000, placed on the left bank of the Vigo estuary (42 degrees 14'15"N, 8 degrees 43'30"W). Pinus has high quantitative importance in the airborne pollen spectrum of the city. It is one of the best represented taxa constituting 13%-20% of the total annual pollen levels. The quantity of Pinus pollen present in the atmosphere of the city of Vigo throughout a year is 5,751 grains (as the average for the sampled years), with a very long pollination period, from the middle of January until May. The maximum concentration was recorded in 1998 with 1,105 grains/m(3) on 3 March, a much greater value than those for the previous years. At the end of its pollination period there is usually a final increase in Pinus pollen concentrations coinciding with the pollination of Pinus silvestris, which are more abundant in mountainous areas far from the city.

Nerve guides seeded with autologous schwann cells improve nerve regeneration

This study evaluates the ability of Schwann cells (SCs) transplanted into a nerve guide to improve regeneration and reinnervation after sciatic nerve resection and repair, leaving a 6-mm gap, in the mouse. SCs were isolated from predegenerated adult sciatic nerves and expanded in culture using a chemically defined medium. Syngeneic, isogeneic, and autologous SCs were suspended in Matrigel and seeded in resorbable, permeable poly(l-lactide-co-epsilon-caprolactone) guides at 150,000 cells/tube. Guides containing SCs were compared to guides filled with Matrigel alone and with peroneal nerve autografts. Functional reinnervation was assessed by noninvasive methods to determine recovery of sweating, nociceptive, sensory, and motor functions in the hindpaw during 4 months postoperation. Morphological analysis of the regenerated nerves was performed at the end of follow-up. The group with an autograft achieved faster and higher levels of reinnervation and higher number of regenerated myelinated fibers than groups repaired by tubulization. The immunogenicity of transplanted SCs influenced the outcome of nerve regeneration. Transplants of autologous SCs resulted in slightly lower levels of reinnervation than autografts, but higher recovery and number of regenerated fibers reaching the distal nerve than transplants of isologous and syngeneic SCs, although most of the differences were not statistically significant. Syngeneic SCs did not improve regeneration with respect to acellular guides. Prelabeled transplanted SCs were found to survive into the guide 1-3 months after implantation, to a larger number when they were autologous than syngeneic. Cellular prostheses composed of a resorbable guide seeded with autologous SCs appear as an alternative for repairing long gaps in injured nerves, approaching the success of autografts.

Highly permeable polylactide-caprolactone nerve guides enhance peripheral nerve regeneration through long gaps

We compared regeneration and functional reinnervation after sciatic nerve resection and tubulization repair with bioresorbable guides of poly(L-lactide-co-epsilon-caprolactone) (PLC) and permanent guides of polysulfone (POS) with different degrees of permeability, leaving a 6 mm gap in different groups of mice. Functional reinnervation was assessed to determine recovery of motor, sensory and sweating functions in the hindpaw during four months postoperation. Highly permeable PLC guides allowed for faster and higher levels of reinnervation for the four functions tested than impermeable or low-permeable PLC guides, while semipermeable 30 and 100 kDa POS tubes yielded very low levels of reinnervation. The regeneration success rate was higher with PLC than with POS tubes. Morphometrical analysis of cross-sectional nerves under light microscopy showed the highest number of regenerated myelinated fibers at mid tube and distal nerve in high-permeable PLC guides. Impermeable PLC guides allowed slightly worse levels of regeneration, while low-permeable PLC guides promoted neuroma and limited distal regeneration. The lowest number of regenerated fibers were found in POS tubes. In summary, highly permeable bioresorbable PLC guides offer a suitable alternative for repairing long gaps in injured nerves, approaching the success of autologous nerve grafts.

Olfactory bulb ensheathing cells enhance peripheral nerve regeneration

Sciatic nerve resection leaving a 15 mm gap could not be repaired by bridging the stumps with a silicone tube prefilled with a laminin gel. However, when purified olfactory ensheathing cells (EC) were added to the gel filling the tube, successful axonal regeneration was observed in 50% of rats. With 12 mm gaps, regeneration occurred in 79% of rats with transplanted EC compared with 60% of those receiving collagen gel alone. Therefore, ECs help repair severe peripheral nerve injuries, in addition to their ability to promote axonal regeneration within the central nervous system.

Physiological and immunohistochemical characterization of cisplatin-induced neuropathy in mice

We investigated the neuropathic effects of cisplatin in two groups of mice treated with 5 or 10 mg/kg/week of cisplatin for 7 or 8 weeks. Peripheral nerve functions were evaluated by sweat imprints, and electrophysiological, rotarod, and nociceptive tests. Protein gene product 9.5 (PGP), calcitonin gene-related peptide (CGRP), and vasoactive intestinal peptide (VIP) were immunohistochemically localized in footpads. Tibial nerves were analyzed morphometrically. Functional deficits developed progressively with higher cumulative doses, more markedly in mice treated with high than in those with low doses. From cumulative doses of 10 mg/kg, significant declines in sensory nerve conduction velocity and sudomotor responses were found, whereas motor and nociceptive functions were involved later. There were no morphometrical changes in tibial nerves. A marked decrease of CGRP- and VIP-immunoreactive nerves occurred in samples from treated mice, whereas PGP-labeled profiles decreased mildly at late stages. Impairment of the content of neuropeptides with neurosecretor role was detectable earlier than functional abnormalities. Immunohistochemical analysis of skin biopsies offers a useful diagnostic tool for peripheral neuropathies.

Ensheathing glia transplants promote dorsal root regeneration and spinal reflex restitution after multiple lumbar rhizotomy

Previously, we have shown that transplants of olfactory bulb ensheathing cells promoted regeneration of transected dorsal roots into the spinal cord. In this study, we assessed the ability of regenerating axons to make functional connections in the cord. Dorsal roots L3 to L6 were sectioned close to their entrance into the spinal cord and reapposed after injecting a suspension of ensheathing cells into each dorsal root entry zone (Group G). Afferent regeneration into the cord and recovery of spinal reflexes were compared with animals that received no injection (Group S) or culture medium without cells (Group C). Electrophysiological tests, to measure nerve conduction and spinal reflexes (H response and withdrawal reflex) evoked by stimulation of afferents of the sciatic nerve, were performed. At 14 days after surgery, H response was found in only 1 of 7 rats of Group G, and withdrawal reflexes were absent from all animals. At 60 days, the H response reappeared in 7 of 10 rats of Group G, and 1 of 5 of each of Groups C and S. The withdrawal reflex recovered in 4 of 10 rats of Group G, but in none of Groups C and S. Immunohistochemical labeling for calcitonin gene-related peptide (CGRP) in rats of Group G showed immunoreactive fibers entering the dorsal horn from sectioned roots, although at lower density than in the contralateral side. In conclusion, transplanted ensheathing cells promoted central regeneration and functional reconnection of regenerating sensory afferents.

Changes in cholinergic responses of sweat glands during denervation and reinnervation

Functional sudomotor responses have been studied in sweat glands reinnervated after sciatic nerve crush and partially denervated by cisplatin intoxication in the mouse. The sudomotor function mediated by the sciatic nerve was evaluated by silicone imprints on the plantar surface of the hindpaws. Five days after nerve crush, completely denervated sweat glands became unresponsive to cholinergic stimulation with pilocarpine. During the following weeks, the number of reinnervated, reactive sweat glands increased progressively to reach a maximum of 89% of preoperative control counts by 40 days after nerve crush. At this time, the mean volume of sweat secreted per gland was normal, but reinnervated glands showed a secretory activity abnormally sustained over time after pilocarpine stimulation and, on the other hand, had an increased resistance to the inhibition of secretion induced by atropine. The effects of cisplatin administration on sudomotor function were investigated in two groups of mice, one treated with high doses of cisplatin (10 mg/kg/week for 4 weeks) and another treated with low doses of cisplatin (5 mg/kg/week for 8 weeks). Cisplatin intoxication produced abnormal sudomotor responses indicative of denervation from cumulative doses of 10 mg/kg. The first abnormality found was a partial resistance of sweat glands to atropine, followed by a decrease in the sweat output per gland and finally a decline in the number of sweat glands activated by pilocarpine. These abnormalities in the sudomotor responses were more pronounced in mice treated with a high dose than in those with a lower dose regime.

Emphysema as a result of involuntary exposure to tobacco smoke: morphometrical study of the rat

Several attempts have been made to describe the relation that exists between tobacco smoke and emphysema, through different experimental models of the active smoker. Despite the negative effects that involuntarily inhaled tobacco smoke can have on the lung, no experimental model of the passive smoker has been proposed. In this study, an experimental model of the involuntary smoker is described and the following hypothesis proposed: Passive exposure to tobacco smoke produces morphological alterations in the rat lung, which are compatible with emphysema. Emphysema will be considered to have been caused when enlargement of the distal airspaces of the lung and lung tissue destruction are demonstrated. Sixty Wistar rats were used, divided into two groups: a control group and a group that was passively exposed to tobacco smoke for a period of 3 months. A morphometrical study of the lung was performed using a computerized system. To demonstrate enlargement of the distal airspaces of the lung, the following variables were quantified: alveolar chord and mean linear intercept index (Lm); tissue loss was demonstrated by means of the quantification of the variables: tissue density, internal alveolar perimeter (IAP), and wall thickness (WT). The elastic fiber was also quantified. The animals that were exposed to tobacco smoke displayed the following significant alterations (p < .05): an increase of the alveolar chord and of the Lm, a decrease of the IAP, WT, and tissue density, and a loss of the elastic component of the lung. On the basis of these findings, it is concluded that the rats that were exposed in a passive way to tobacco smoke display morphological pulmonary alterations that are compatible with the definition of emphysema.

[Historical course of surgical techniques in pancreas transplantation]

Since the original description of the pancreas transplant technique in animals, initially as a pedicle transplant in 1892, free graft in 1913, and then as a vascularized organ in 1927, there have been several changes in the handling of the exocrine secretions, as well as the vascular anastomoses, and the posttransplant function in relation to the immunosuppressive therapy. The surgical technical changes have included the ligature of the duct, the free drainage to the abdominal cavity, the pancreas transplant with a duodenal segment, the chemical occlusion of the duct, and its drainage to the intestine or to the bladder with a duodenal segment. This last technique remains as the standard technique currently used for pancreas transplantation, along with the combined transplant of the kidney. This work reviews the historical aspects, the evolution of the experimental and clinical surgical techniques, and the current results associated with the surgical management of pancreas transplantation.

Presumed occlusion of posterior ciliary arteries following central retinal vein decompression surgery

OBJECTIVE

Sectioning of the posterior scleral ring has been advocated in the treatment of central retinal vein occlusion. We reviewed cases in which this surgery apparently produced sectioning or closure of the short and long posterior ciliary arteries that resulted in a triangular area of choroidal ischemia and permanent chorioretinal lesions.

DESIGN

Case series.

SETTING

Clinic-based vitreoretinal referral practice.

PATIENTS

Four eyes of three patients whose ages ranged from 17 to 53 years underwent sectioning of the posterior scleral rings as treatment for central retinal vein occlusion.

MAIN OUTCOME MEASURES

Findings from complete ophthalmologic evaluation.

RESULTS

All patients had either an oval or a triangular area of choroidal ischemia nasal to the optic disc and had permanent chorioretinal lesions.

CONCLUSIONS

Valid basis for performing this operation requires further investigation.

Separation and determination of aminohalogenbenzophenones by high-performance liquid chromatography with electrochemical detection

A high-performance liquid chromatographic method with electrochemical detection has been developed for the determination of three aminohalogenbenzophenones: 2-amino-2',5-dichlorobenzophenone, 2-amino-5-chlorobenzophenone and 2-amino-5-bromo-2'-fluorobenzophenone, metabolites of benzodiazepinooxazoles and other psychotropic drugs. A mobile phase of methanol-water (65:35), containing 5 mM KH2PO4 appeared to be the optimal when a 4-microns, 60-A Nova-Pak C18 column and a flow-rate of 0.75 ml/min (130 bar) were used. The temperature was optimized at 30 degrees C. The amperometric detector, equipped with glassy carbon electrode, was operated at 1.3 V versus Ag/AgCl in the DC mode. The method was applied to the determination of these compounds at two concentration levels: ppm and ppb (ng/cm3) using 2-amino-5-chlorobenzophenone as internal standard. The limit of determination was 750 pg/ml of biological fluid for each compound, and recoveries greater than 97% were obtained for spiked samples of urine and serum, using C18 Sep-Pak cartridges in the sample clean-up procedure.

Simple radioimmunological method for urinary 6-keto-PGF1 alpha measurement

A radioimmunoassay for the determination of 6-keto-PGF1 alpha (stable metabolite of Prostacyclin) in urine using a specific antiserum, is described. The antibody used, showed no significant cross-reactivity with other PGS. (3H)-6-keto-PGF1 alpha has been used as tracer and a 30% Hydroxyapatite suspension was utilized for the separation of bound and free fractions. Standard curve ranges between 2 and 1000 pg thus allowing measurements in urine. Aliquots of 0.2 to 1 ml of 24 hours urinary samples were submitted to a preextraction step with Hexane in order to eliminate neutral fats. After acidifying with 0.1 N HCl to pH = 3.5-4, an Ethyl Ether extraction step was performed showing a recovery of 66%. Repeated analysis of a rat urine pool, showed 7.7 intraassay and 9.8 interassay variation coefficients. Values obtained amounted to 38.3 +/- 4.6 ng/24 h in normal rats and 133 +/- 32 ng/24 h in 5% NaCl loaded rats (p less than 0.001). The values obtained in healthy men were 508 +/- 94 ng/24 h and in women 375 +/- 136 (p less than 0.05).

Response of plasma aldosterone to orthostatism during follicular and luteal phases of the normal menstrual cycle

The responses of plasma aldosterone (A) and plasma renin activity (PRA) to orthostatism have been evaluated in 47 women during the follicular and/or luteal phase of the menstrual cycle. Three postmenopausal women and 51 men were also studied for control. Fourteen cycling women and 11 men were studied on a low sodium diet (20 mEq/day) while the rest of the subjects were on normal sodium intake. In addition, 18 women (including those postmenopausal) and 17 men were studied after intravenous administration of 20 mg frusemide. The response of A to orthostatism in women during luteal phase on normal sodium diet with or without frusemide was much greater than in men or women during follicular phase (p less than 0.01) or menopuase (p less than 0.05). However, no differences between groups could be observed in A response while on a low sodium diet. PRA response was similar during follicular of luteal phase fo the cycle as well as in men either on low or normal sodium intake with or without frusemide.