Tubulointerstitial Nephritis and Uveitis Syndrome (TINU) after Intake of Dietary Supplement.

INTRODUCTION: The pathogenesis of tubulointerstitial nephritis with uveitis syndrome (TINU) is thought to be an interplay between environmental and genetic factors leading to an inappropriate immune response. METHODS: Report of a clinical case. RESULTS: We present a case of TINU syndrome which meets the clinical and anatomopathological features according to the classification criteria of the standardization of uveitis nomenclature (SUN) working group. The only possible causal agent was found to be the intake of a nutritional supplement. CONCLUSION: Our case highlights the role of environmental factors as triggers for this disorder.

Diagnostic and Management Strategies of Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): Current Perspectives.

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare autoimmune disease with unclear pathogenesis but probably related to a combination of genetic predisposition and environmental triggers. Diagnosis is challenging due to the asynchronous onset of renal and ocular symptoms, and it is necessary to exclude other causes of nephritis and uveitis. It affects both sexes, with an overall predominance of females and a median age of onset of 15 years. TINU syndrome is characterized by bilateral, non-granulomatous anterior uveitis and tubulointerstitial nephritis, which can cause acute renal failure in severe cases. Several triggers have been identified including concurrent infections, medications, or endocrine diseases. The diagnosis of TINU is mainly based on clinical and analytical findings, and although urinary ß2-microglobulin is a useful parameter no specific diagnostic test is available. Current perspectives intend to facilitate its diagnosis identifying susceptibility HLA genotypes, serologic markers and imaging tools to avoid renal biopsy. Treatment options for TINU syndrome include corticosteroids, immunosuppressive agents, and intravenous immunoglobulins, but relapses are frequent, and management can be challenging. The purpose of this review is to provide an updated summary of the diagnostic and treatment strategies of TINU syndrome, helping clinicians recognize and manage this rare autoimmune disorder.

Hypopyon Uveitis as a Manifestation of Primary Choroidal Lymphoma.

A 78-year-old female was referred to our hospital due to a decrease of visual acuity in her left eye. On examination, presence of left choroidal folds and subretinal fluid was disclosed. After being misdiagnosed as neovascular age-related macular degeneration treatment with intravitreal injections of Aflibercept was started. Despite improvement of fluid, persistence of choroidal folds encouraged a magnetic resonance imaging revealing a left retrobulbar nodular lesion. Furthermore, development of hypopyon during follow-up allowed a flow cytometry analysis of an aqueous humour sample that confirmed infiltration by a non-Hodgkin mature B-cell lymphoproliferative process. Finally, treatment with Rituximab and intravenous corticosteroids achieved complete resolution. Primary choroidal lymphoma may occur with an atypical presentation, including hypopyon uveitis. Thus, familiarity with its clinical features is fundamental for an early recognition and correct management.

Robotic Magnetic Surgery: Results From the First Prospective Clinical Trial.

To evaluate a novel Magnetic Robotic Platform during reduced-port laparoscopic surgery in a prospective, multicenter clinical trial. Background: Magnetic surgery has been developed to increase the benefits of minimally invasive surgery, with prior studies demonstrating its clinical benefits. Robotic-assisted surgery increases the surgeon's control over the instruments, offering less dependency on an assistant. The synergism of both techniques may escalate these individual benefits. Methods: A prospective, multicenter, single-arm, open-label study was performed to assess the safety and performance of a robotic magnetic surgical system (Levita Robotic Platform). The investigational device was used during reduced-port laparoscopic cholecystectomy and laparoscopic bariatric surgery. The primary endpoints evaluated were safety and feasibility. Patients were followed for 30 days post-procedure. Results: Between May 2021 and December 2021, 30 patients undergoing laparoscopic surgery were recruited. There were 22 females and 8 males with a mean age of 39 years (22-69 years) and median body mass index of 33 kg/m2 (21.6-50.4 kg/m2). Procedures included 15 gastric sleeves, 14 cholecystectomies, and 1 Roux en-Y gastric bypass. The procedures were successfully performed by utilizing the robotic magnetic surgical system and a reduced-port technique in all 30 patients. No device-related serious adverse events were reported. The device provided adequate visualization and retraction in all cases. Conclusions: This clinical trial shows for the first time that this novel Magnetic Robotic Platform is safe and feasible in reduced-port laparoscopic cholecystectomy and laparoscopic bariatric surgery. This robotic platform brings the benefits of magnetic surgery in terms of reduction of incisions plus increasing the control for the surgeon.

Consenso chileno de diagnóstico y manejo de neoplasias quísticas pancreáticas. Club de páncreas Chile-SCHGE / Chilean consensus on diagnosis and management of pancreatic cystic neoplasms

Pancreatic cystic neoplasms (PCN) are frequently detected on abdominal images performed for non-pancreatic indications. Their prevalence in asymptomatic population ranges from 2.7 to 24.8%, and increases with age. There are several types of pancreatic cysts. Some may contain cancer or have malignant potential, such as mucinous cystic neoplasms, including mucinous cystadenoma (MCN) and intraductal papillary mucinous neoplasms (IPMN). In contrast, others are benign, such as serous cystadenoma (SCA). However, even those cysts with malignant potential rarely progress to cancer. Currently, the only treatment for pancreatic cysts is surgery, which is associated with high morbidity and occasional mortality. The Board of the Chilean Pancreas Club of the Chilean Gastroenterology Society developed the first Chilean multidisciplinary consensus for diagnosis, management, and surveillance of PCN. Thirty experts were invited and answered 21 statements with five possible alternatives: 1) fully agree; 2) partially agree; 3) undecided; 4) disagree and 5) strongly disagree. A consensus was adopted when at least 80% of the sum of the answers "fully agree" and "partially agree" was reached. The consensus was approved by the Board of Directors of the Chilean Pancreas Club for publication.

[Chilean consensus on diagnosis and management of pancreatic cystic neoplasms]. / Consenso chileno de diagnóstico y manejo de neoplasias quísticas pancreáticas. Club de páncreas Chile-SCHGE.

Pancreatic cystic neoplasms (PCN) are frequently detected on abdominal images performed for non-pancreatic indications. Their prevalence in asymptomatic population ranges from 2.7 to 24.8%, and increases with age. There are several types of pancreatic cysts. Some may contain cancer or have malignant potential, such as mucinous cystic neoplasms, including mucinous cystadenoma (MCN) and intraductal papillary mucinous neoplasms (IPMN). In contrast, others are benign, such as serous cystadenoma (SCA). However, even those cysts with malignant potential rarely progress to cancer. Currently, the only treatment for pancreatic cysts is surgery, which is associated with high morbidity and occasional mortality. The Board of the Chilean Pancreas Club of the Chilean Gastroenterology Society developed the first Chilean multidisciplinary consensus for diagnosis, management, and surveillance of PCN. Thirty experts were invited and answered 21 statements with five possible alternatives: 1) fully agree; 2) partially agree; 3) undecided; 4) disagree and 5) strongly disagree. A consensus was adopted when at least 80% of the sum of the answers "fully agree" and "partially agree" was reached. The consensus was approved by the Board of Directors of the Chilean Pancreas Club for publication.

Innovative design of a methodology for the simultaneous determination of compounds by kinetic-spectroscopy three-dimensional chemiluminescence.

This report presents a novel methodology based in the quickly acquisition of full UV-vis range spectra combined with the joint determination of kinetic parameters and chemiluminescence signals. Then this technique allows obtaining three-dimensional chemiluminescence spectra profiles containing kinetic and spectroscopic information. That is especially useful for resolving mixtures of luminophors because of more analytical information for each analyte is available increasing the selectivity relative to conventional chemiluminescence methods. To accomplish this, a conventional Back-Thinned CCD detector is used and the three-dimensional chemiluminescence spectra is subsequently processed so that two-dimensional spectra with different trajectories can be obtained by dedicated software CLTotal. The potential of the proposed analytical methodology was assessed for the simultaneous determination of two polycyclic aromatic hydrocarbons. The chemiluminescent reaction between DNPO and hydrogen peroxide induced by their presence was used to record 3D spectra and the software CLTotal to subsequently construct linear variable-angle trajectories in the spectra, in order to obtain more selective 2D spectra facilitating the simultaneous determination of the analytes. The results of the statistical analysis testify to the usefulness of the proposed method for the intended purpose.

Magnetic Surgery: Results From First Prospective Clinical Trial in 50 Patients.

OBJECTIVE: To evaluate a new magnetic surgical system during reduced-port laparoscopic cholecystectomy in a prospective, multicenter clinical trial. BACKGROUND: Laparoscopic instrumentation coupled by magnetic fields may enhance surgeon performance by allowing for shaft-less retraction and mobilization. The movements can be performed under direct visualization, generating different angles of traction and reducing the number of trocars to perform the procedure. This may reduce well-known associated complications of trocars, including incisional pain, scarring, infection, bowel, and vascular injuries, among others. METHODS: A prospective, multicenter, single-arm, open-label study was performed to assess the safety and performance of a magnetic surgical system (Levita Magnetics' Surgical System). The investigational device was used during a 3-port laparoscopic technique. The primary endpoints evaluated were safety and feasibility of the device to adequately mobilize the gallbladder to achieve effective exposure of the targeted surgical site. Patients were followed for 30 days postprocedure. RESULTS: Between January 2014 and March 2015, 50 patients presenting with benign gallbladder disease were recruited. Forty-five women and 5 men with an average age of 39 years (18-59), average body mass index of 27 kg/m (20.4-34.1) and an average abdominal wall thickness of 2.6 cm (1.8-4.6). The procedures were successfully performed in all 50 patients. No device-related serious adverse events were reported. Surgeons rated as "excellent" (90%) or "sufficient" (10%) the exposure of the surgical site. CONCLUSIONS: This clinical trial shows that this new magnetic surgical system is safe and effective in reduced-port laparoscopic cholecystectomy.

Reversal of the Hartmann's procedure: A comparative study of laparoscopic versus open surgery.

BACKGROUND: The Hartmann's operation, although less frequently performed today, is still used when initial colonic anastomosis is too risky in the short term. However, the subsequent procedure to restore gastrointestinal continuity is associated with significant morbidity and mortality. PATIENTS AND METHODS: The review of an institutional review board (IRB)-approved prospectively maintained database provided data on the Hartmann's reversal procedure performed by either laparoscopic or open technique at our institution. The data collected included: demographic data, operative approach, conversion for laparoscopic cases and perioperative morbidity and mortality. RESULTS: Over a 14-year period from January 1997 to August 2011, 74 Hartmann's reversal procedures were performed (laparoscopic surgery-49, open surgery-25). The average age was 55 years for the laparoscopic and 57 years for the open surgery group, respectively. Male patients represent 61% of both groups. There was no significant difference in operative time between the two groups (149 min vs 151 min; P = 0.95), and there was a tendency to lower morbidity (3/49-7.3% vs 4/25-16%; P = 0.24) in the laparoscopic surgery group. In the laparoscopic group, eight patients (16.3%) were converted to open surgery, mostly due to severe adhesions. The length of hospital stay was significantly shorter for the laparoscopic group (5 days vs 7 days; P = 0.44). CONCLUSIONS: The Hartmann's reversal procedure can be safely performed in the majority of the cases using a laparoscopic approach with a low morbidity rate and achieving a shorter hospital stay.

Corynebacterium striatum: an emerging nosocomial drug-resistant endocardial pathogen.

Endocarditis due to Corynebacterium striatum has been rarely reported. A 78-year-old patient developed pacemaker endocarditis caused by multidrug-resistant C. striatum, complicated by vertebral osteomyelitis and epidural abscess. Daptomycin therapy successfully eradicated the bacteremia and metastatic infection. A review of the English literature on this emerging nosocomial, multidrug-resistant pathogen is included.

The use of steroids to prevent cutaneous reactions to benznidazole in patients with Chagas disease.

The treatment of Chagas disease is limited by the frequent cutaneous side effects of benznidazole. We tested the use of steroids plus escalating doses of benznidazole to prevent this complication in 17 adult patients with chronic Trypanosoma cruzi infection and found extremely good tolerance. A randomized trial is warranted.

Escurrimiento oleoso anaranjado o «keriorrea», («orange oily anal leakage»): una nueva enfermedad ligada a cambios de hábito alimentario / Orange oily anal leakage: a new entity linked to dietary changes

Introducción Se acumula información relativa a casos clínicos de excepción, relacionados con la ingesta de determinados alimentos y con su forma de consumo, los que presentan un cuadro caracterizado por descarga anal, las más de las veces inadvertida, de líquido anaranjado oleoso que alarma a los pacientes. Método Se registran los antecedentes de una serie de casos recogidos de forma consecutiva, que presentan un cuadro clínico caracterizado por descarga masiva e involuntaria, sin sensación esfinteriana, de deposiciones de aspecto oleoso anaranjado después de ingerir pescado en la gran mayoría de los casos, de cocina japonesa. Resultados Se evaluaron 11 pacientes con el cuadro clínico mencionado. Cuatro mujeres y siete de ellos varones. Edad promedio de 47,3 años. Cuatro pacientes tenían estudio colonoscópico previo sin lesiones. La keriorrea se produciría por acumulación de «ésteres cerosos» no digeribles, presentes en algunos peces escolares, algunos de ellos incorporados recientemente a la ingesta cruda en forma de sashimi o mal llamados mero cocido. Estos aceites, al ser no absorbibles ni digeribles, se filtran insensiblemente desde el recto. También se postularía una disfunción esfinteriana secundaria a toxinas. En ocasiones se produce la misma sintomatología por consumo de estas especies en su forma cocida. El antecedente epidemiológico de ingesta previa de pescado de las características mencionadas, los datos clínicos y lo autolimitado del cuadro, permiten el diagnóstico sin necesidad de realizar mayores estudios. Conclusión Se describe y comunica una serie de casos, de enfermedad recientemente descrita, asociada a cambios de hábito alimentario, de curso benigno y autolimitado. Nos parece importante que este cuadro sea reconocido por los clínicos, para informar a los pacientes y manejar correctamente estos casos(AU)

Introduction Information is accumulating on exceptional cases of oily orange anal leakage, probably caused by certain foods and their form of consumption. The leakage is usually inadvertent and is worrisome for patients. Method Clinical data was gathered on a case series presenting with massive and inadvertent orange oily anal leakage, without sphincter sensation, causing the patients to feel alarmed. This condition usually occurs after eating fish, especially Japanese cuisine. Results Eleven patients were included (four women and seven men). The mean age was 47.3 years. Colonoscopy had previously been performed in four patients, with normal results. The symptoms, described as keriorrhea, were probably produced by accumulation of indigestible "wax esters", es Mero present in some oily fish, recently incorporated in raw fish dishes (sashimi) or as Japanese Mero sea bass. These oils, which cannot be absorbed or digested, accumulate in the rectum and may also filter spontaneously and induce toxin-related sphincter dysfunction. The same symptoms are sometimes produced after consumption of cooked versions of these species. The diagnosis is given by clinical data, prior ingestion of these types of fish and the self-limiting nature of the symptoms, without the need for further investigations. Conclusion We describe a case series of a recently described entity associated with dietary changes. This entity is benign and self-limiting. Clinicians should be familiar with the symptoms to inform patients correctly and avoid unnecessary laboratory studies(AU)

[Orange oily anal leakage: a new entity linked to dietary changes]. / Escurrimiento oleoso anaranjado o "keriorrea", ("orange oily anal leakage"): una nueva enfermedad ligada a cambios de hábito alimentario.

INTRODUCTION: Information is accumulating on exceptional cases of oily orange anal leakage, probably caused by certain foods and their form of consumption. The leakage is usually inadvertent and is worrisome for patients. METHOD: Clinical data was gathered on a case series presenting with massive and inadvertent orange oily anal leakage, without sphincter sensation, causing the patients to feel alarmed. This condition usually occurs after eating fish, especially Japanese cuisine. RESULTS: Eleven patients were included (four women and seven men). The mean age was 47.3 years. Colonoscopy had previously been performed in four patients, with normal results. The symptoms, described as keriorrhea, were probably produced by accumulation of indigestible "wax esters", es Mero present in some oily fish, recently incorporated in raw fish dishes (sashimi) or as Japanese Mero sea bass. These oils, which cannot be absorbed or digested, accumulate in the rectum and may also filter spontaneously and induce toxin-related sphincter dysfunction. The same symptoms are sometimes produced after consumption of cooked versions of these species. The diagnosis is given by clinical data, prior ingestion of these types of fish and the self-limiting nature of the symptoms, without the need for further investigations. CONCLUSION: We describe a case series of a recently described entity associated with dietary changes. This entity is benign and self-limiting. Clinicians should be familiar with the symptoms to inform patients correctly and avoid unnecessary laboratory studies.

Simultaneous determination of plant growth regulators 1-naphthylacetic acid and 2-naphthoxyacetic acid in fruit and vegetable samples by room temperature phosphorescence.

INTRODUCTION: 1-Naphthylacetic and 2-naphthoxyacetic acids belong to the synthetic branch of auxins. Auxins have attracted considerable interest as a subject of study by virtue of their biological and physiological significance. Their broad use as plant growth regulators has raised the need for simple, rapid, sensitive and selective analytical methods for their determination in real samples. OBJECTIVE: The primary aim of this work was to develop an analytical method for the simultaneous determination of 1-naphthylacetic acid and 2-naphthoxyacetic acid in commercial technical formulations, tomato and various fruit types (apple, strawberry, orange and plum) by room temperature phosphorescence. METHODOLOGY: Filtrated solutions of aqueous slurries from ecological fruit and tomato samples are acidified and then extracted with dichloromethane. Once the solvent is evaporated, the dried residue is dissolved in sodium dodecyl sulphate (a micellar agent), and supplied with thallium (I) nitrate as an external heavy atom source and sodium sulphite as deoxygenation agent to enhance the ensuing phosphorescence. RESULTS: The broad-band overlapping spectra for the two analytes were resolved by first- and second-derivative phosphorescence spectrometry. Zero-crossing measurements at 488.5 nm in the first-derivative spectrum and 469.5 nm in the second derivative spectrum exhibited a linear dependence on the 2-naphthoxyacetic acid and 1-naphthylacetic acid concentration, respectively. The detection limits as determined in accordance with the error propagation theory were 11.5 ng/mL for 1-naphthylacetic acid and 15.6 ng/mL for 2-naphthoxyacetic acid. CONCLUSION: The proposed method affords the determination of 1-naphthylacetic acid and 2-naphthoxyacetic acid in real samples with near-quantitative recoveries from agricultural products.

Kinetic-spectrometric three-dimensional chemiluminescence as an effective analytical tool. Application to the determination of benzo(a)pyrene.

Kinetic and spectroscopic methods were used in combination in this work to develop a new analytical tool for use in chemiluminescence detection processes. Specifically, time-resolved chemiluminescence was used jointly with a stopped-flow assembly in order to monitor the chemiluminescence produced in the oxidation of bis(2,4-dinitrophenyl)oxalate (DNPO) by hydrogen peroxide in the presence of a polycyclic aromatic hydrocarbon. Recording of successive two-dimensional spectra during the emission process and treating the acquired spectral data with dedicated software allows the obtainment of three-dimensional chemiluminescence spectra, a result of the joint use of two analytical techniques. Thus, using a flow cell specifically designed for direct coupling to the charge-coupled device (CCD) detector increases the emission intensity without the need for fibre optics. Also, using dedicated software to process the acquired two-dimensional spectra affords a comprehensive kinetic and spectroscopic characterization of the chemiluminescence signal via the three-dimensional spectrum previously obtained. The analytical potential of this new tool was assessed by application to the chemiluminescent reaction between a peroxyoxalate and an oxidant (hydrogen peroxide); the reaction is induced by benzo(a)pyrene, which was used to determine this polycyclic aromatic hydrocarbon in an organic solvent. A linear calibration graph was obtained between 0.5 and 20 mg L(-1). The limit of detection found to be 3.97 µg L(-1) and a relative standard error of 0.64% and a relative standard deviation of 1.87% were obtained. The results reached testify to the usefulness of the proposed analytical tool for simple determinations and its potential for the resolution of complex mixtures or determinations in complex matrices.

Rapid simultaneous determination of four non-steroidal anti-inflammatory drugs by means of derivative nonlinear variable-angle synchronous fluorescence spectrometry.

A rapid, simple, and inexpensive spectrofluorimetric method has been proposed for the simultaneous quantification of diflunisal, salicylic acid, fenoprofen, and 6-methoxy-2-naphthylacetic acid (6MNA). First-derivative nonlinear variable-angle synchronous fluorescence spectrometry has been developed to improve the selectivity of fluorescence measurements without loss of sensitivity. It allows the simultaneous determination of different substances in a mixture from a single spectrum based on a single scan. The analyses were performed in an ethanol-water (70%) medium at a pH of 9.2, adjusted by using ammonium/ammonia (0.5 M) as a buffer solution. The linear concentration ranges are 30.0-100.0, 100.0-600.0, 50.0-150.0, and 30.0-100.0 ng/mL for salicylic acid, fenoprofen, diflunisal, and 6-methoxy-2-naphthylacetic acid, respectively, at lambda(ex)/lambda(em) = 281.1/423.6, 241.2/301.2, 284.1/403.8, and 268.7/339.6 nm, respectively. Analytical parameters of the proposed method were calculated according to the error propagation theory. The sensitivity, repeatability, reproducibility, and limits of detection achieved with the proposed method are adequate for the determination of these anti-inflammatory drugs.

Plasticity in primary somatosensory cortex resulting from environmentally enriched stimulation and sensory discrimination training

We studied primary-somatosensory cortical plasticity due to selective stimulation of the sensory periphery by two procedures of active exploration in adult rats. Subjects, left with only three adjacent whiskers, were trained in a roughness discrimination task or maintained in a tactile enriched environment. Either training or enrichment produced 3-fold increases in the barrel cortex areas of behaviorally-engaged whisker representations, in their zones of overlap. While the overall areas of representation expanded dramatically, the domains of exclusive principal whisker responses were virtually identical in enriched vs normal rats and were significantly smaller than either group in roughness discrimination-trained rats. When animals were trained or exposed to enriched environments with the three whiskers arrayed in an are or row, very equivalent overlaps in representations were recorded across their greatly-enlarged whisker representation zones. This equivalence in distortion in these behavioral preparations is in contradistinction to the normal rat, where overlap is strongly biased only along rows, probably reflecting the establishment of different relations with the neighboring cortical columns. Overall, plasticity phenomena are argued to be consistent with the predictions of competitive Hebbian network plasticity.

Non-homogeneous spatial configuration of vibrissae cortical representation in layer IV of the barrel somatosensory cortex

In the present experiments we studied exclusive and overlapping cortical representational areas of the vibrissae in layer IV cells, across the entire barrel subfield of the rat somatosensory cortex, looking for evidences that would challenge the present assumptions of homogeneity and symmetry among cortical columns in this sensorial system. Our main findings were that in layer IV of the rat barrel cortex: A) Size of vibrissae cortical representational areas (X=0.4174mm²; SD=0.025) was not homo geneous, vibrissae in dorsal rows (A-B) had significantly smaller areas than those in ventral rows (D-E), a pattern that repeated itself in arcs 1-4. B) This difference arises from vibrissal representational overlap, and not from variations in exclusive zones, which are surprisingly homogeneous in size across the barrel cortex (X=0.079mm²; SD=0.0075); C) The extent of overlapping cortical areas varied systematically, with intra-row overlapping areas having a predominant bias (71.4 percent of total overlapping) independent of area sizes. Accordingly, vibrissae shared receptive fields with an average of 1.15 vibrissae in the same row and 0.38 in the same are. Barrel cortex has been viewed operationally as a conglomerate of essentially homogenous cortical columns that interact equivalently in the are and row dimensions. Our simple but global cortical reconstructions show that this predominant view should be revised. We postulate that the vibrissae/barrels spatial disposition in rows and ares has a relevant functional meaning, related to different sensory capabilities.

Plasticity in primary somatosensory cortex resulting from environmentally enriched stimulation and sensory discrimination training.

We studied primary-somatosensory cortical plasticity due to selective stimulation of the sensory periphery by two procedures of active exploration in adult rats. Subjects, left with only three adjacent whiskers, were trained in a roughness discrimination task or maintained in a tactile enriched environment. Either training or enrichment produced 3-fold increases in the barrel cortex areas of behaviorally-engaged whisker representations, in their zones of overlap. While the overall areas of representation expanded dramatically, the domains of exclusive principal whisker responses were virtually identical in enriched vs normal rats and were significantly smaller than either group in roughness discrimination-trained rats. When animals were trained or exposed to enriched environments with the three whiskers arrayed in an are or row, very equivalent overlaps in representations were recorded across their greatly-enlarged whisker representation zones. This equivalence in distortion in these behavioral preparations is in contradistinction to the normal rat, where overlap is strongly biased only along rows, probably reflecting the establishment of different relations with the neighboring cortical columns. Overall, plasticity phenomena are argued to be consistent with the predictions of competitive Hebbian network plasticity.