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At least 595 records · Page 33Linked to original sources
PubMed2005

Navigation with electromagnetic tracking for interventional radiology procedures: a feasibility study.

PURPOSE: To assess the feasibility of the use of preprocedural imaging for guide wire, catheter, and needle navigation with electromagnetic tracking in phantom and animal models. MATERIALS AND METHODS: An image-guided intervention software system was developed based on open-source software components. Catheters, needles, and guide wires were constructed with small position and orientation sensors in the tips. A tetrahedral-shaped weak electromagnetic field generator was placed in proximity to an abdominal vascular phantom or three pigs on the angiography table. Preprocedural computed tomographic (CT) images of the phantom or pig were loaded into custom-developed tracking, registration, navigation, and rendering software. Devices were manipulated within the phantom or pig with guidance from the previously acquired CT scan and simultaneous real-time angiography. Navigation within positron emission tomography (PET) and magnetic resonance (MR) volumetric datasets was also performed. External and endovascular fiducials were used for registration in the phantom, and registration error and tracking error were estimated. RESULTS: The CT scan position of the devices within phantoms and pigs was accurately determined during angiography and biopsy procedures, with manageable error for some applications. Preprocedural CT depicted the anatomy in the region of the devices with real-time position updating and minimal registration error and tracking error (<5 mm). PET can also be used with this system to guide percutaneous biopsies to the most metabolically active region of a tumor. CONCLUSIONS: Previously acquired CT, MR, or PET data can be accurately codisplayed during procedures with reconstructed imaging based on the position and orientation of catheters, guide wires, or needles. Multimodality interventions are feasible by allowing the real-time updated display of previously acquired functional or morphologic imaging during angiography, biopsy, and ablation.

Angiography↗
PubMed1997

Limitations of the principal-axes theory.

The classical principal-axes transformation (PAT) has been used in numerous publications for three-dimensional (3-D) reconstructions by sequential alignment of histological sections. However, the PAT can determine at most 1/2n(n + 1) parameters (scaling-rotation) in n dimensions. Distortions (shearing) of histological sections can be described by an affine transformation with n2 parameters. An analytical model is devised for calculating rotational and scaling errors which can be determined by relating the transformation parameters of the PAT to the exact solution of a singular value decomposition (SVD) of the perturbation matrix. The results show that form and deformation of the form are intertwined and that these results can be transferred to real data. The model is important for assessing the quality that can be expected with the PAT for 3-D reconstructions if no multimodality reference is available (rigid transformation) and reveals the misalignment in terms of rotational and scaling errors resulting from the PAT as derived in a previously published paper.

Diagnostic Imaging↗
PubMed1991

Endotoxin filtration and immune stimulation improve survival from gram-negative sepsis.

Polymyxin B, when bound to a polystyrene fiber (PMX-F), has been used experimentally as an extracorporeal blood filter to reduce serum lipopolysaccharide levels, which are believed to be responsible for physiologic alterations in the septic state. To validate our theory that a combination of PMX-F, systemic antibiotics, and immune stimulation would improve survival, 78 rats were given intravenous doses of Escherichia coli (range, 4.6 to 6.2 X 10(8) colony-forming units/ml). They were then randomized into groups receiving either systemic gentamicin (n = 10); pretreatment with muramyl dipeptide (n = 11); or extracorporeal hemoperfusion through either a sham column (n = 8), PMX-F-packed column with systemic gentamicin (n = 8); or PMX-F-packed column with systemic gentamicin and muramyl dipeptide pretreatment (n = 8). Thirty-three control rats received no treatment. Sham hemoperfusion (13%) and control (21%) rats had the lowest survival rate, although increased improvement was noted in rats treated with gentamicin (30%) or the combination of PMX-F filtration and gentamicin (50%). The most significant improvements occurred in rats pretreated with muramyl dipeptide (53%) and in rats treated with a combination of PMX-F, gentamicin, and muramyl dipeptide (88%). These data show that lipopolysaccharide filtration and nonspecific immune stimulation are additive to antibiotic therapy and are useful as adjunctive measures in the multimodal treatment of experimental gram-negative bacterial infection.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1995

[Volumetry of abdominal tumors. Problems--feasibility].

If multimodal tumor therapy in the abdomen is to be effective, exact staging is required for which one needs precise planimetric and volumetric data. The most important indication for clinically reliable volumetric determination of tumor size in the abdominal region is monitoring liver metastases during chemotherapy. Determination of volume can be effectively realized using 3D reconstruction. Therefore, the primary data set must be complete and contiguous. The mass should be depicted strongly enhanced and free of artifacts. At present, this prerequisite can only be complied with using thin-slice spiral CT. Phantom studies have proven that a semiautomatic reconstruction algorithm is recommendable. The basic difficulties involved in volumetric determination of tumor size are the problems in differentiating active malignant mass and changes in the surrounding tissue, as well as the lack of histomorphological correlation. Possible indications for volumetry of gastrointestinal masses in the assessment of neoadjuvant therapeutic concepts are under scientific evaluation.

Abdominal Neoplasms↗
PubMed1996

Hyperthermia in the multimodal therapy of advanced rectal carcinomas.

The synergistic effects of hyperthermia (raising temperatures to 40 degrees C and above) when combined with radiotherapy and cytotoxic drugs and a modulation of immunological phenomena have been demonstrated in the laboratory. Pre-clinical data relating to hyperthermia are summed up, along with their implications for clinical application. Controlled studies of local and regional hyperthermia have been performed during recent years, and these show us that the adjunction of hyperthermia provides at least an improvement of local control compared with radiotherapy alone. Current clinical results are summarized. Therapy systems based on radiowave irradiation have been commercially available for regional hyperthermia of the pelvis since the mid 1980s. This technology allows us to perform sufficiently tolerable and effective regional hyperthermia on rectal carcinomas. Used as part of curative preoperative and postoperative multimodal therapeutic strategies, hyperthermia can lead to improvement in local control (resectability, down-staging, progression-free time, recurrence rate), at least for certain risk groups. The preoperative radio-chemo-thermotherapy of advanced primary and recurring rectal carcinoma, uT3/4, was tested in a phase-I/II study of 20 patients. Therapy procedure, acute toxicity, thermal parameters, and response are described and discussed for this patient group. The regimen proved to be sufficiently tolerable, and complications did not occur. Tumor resection was performed on 14 of the 20 patients; 13 of the procedures were R0-resections and one was an R2 resection. In 64% of the resected rectal carcinomas, histopathological down-staging of the pretherapeutic endosonographical stadium was achieved; in three of the patients, despite continued non-resectability, local control has now been maintained for more than 12 months. In two patients with nonresectable rectal carcinomas, local progress was seen during the neoadjuvant combination therapy.

Clinical Trials as Topic↗
PubMed1989

The prognostic significance of basic anthropometric data in children with advanced solid tumors.

In pediatric cancer patients, malnutrition is commonly observed. This may represent the metabolic effect of the primary disease or it may be a consequence of multimodal therapy. This report evaluates the efficacy of using basic anthropometric measurements to predict morbidity during therapy. Twenty children with Wilms' tumor (Stage III, IV, and V) or neuroblastoma (Stage IV) diagnosed at Children's Hospital (Columbus, OH) between January 1983 and December 1985 were evaluated. When compared with the Wilms' tumor patients, the children with neuroblastoma had a significantly lower weight for age at diagnosis. At the completion of therapy, both weight-for-height and weight-for-age measurements were statistically lower in the neuroblastoma group (p less than 0.05). Significant differences were observed between the neuroblastoma and Wilms' tumor patients in the morbidity reported during therapy. Children with neuroblastoma had more frequent hospital admissions, spent a much greater proportion of their treatment time as hospital inpatients, experienced longer delays in therapy, and sustained many more complications. Each of the anthropometric indices was evaluated as a predictor of the complications observed during treatment. In the Wilms' tumor group, the patients with lower weight-for-height percentiles had an increased incidence of incomplete drug infusions, many more complications, more frequent hospital admissions, and an increase in the percentage of time spent as hospital inpatients. In the neuroblastoma group, the anthropometric measurements had no correlation with the subsequent development of complications. Nutritional staging based on anthropometric measurements recorded at diagnosis may be useful in predicting an increased risk of morbidity during therapy in children with Wilms' tumor.

Abdominal Neoplasms↗
PubMed2005

Does multimodal analgesia with acetaminophen, nonsteroidal antiinflammatory drugs, or selective cyclooxygenase-2 inhibitors and patient-controlled analgesia morphine offer advantages over morphine alone? Meta-analyses of randomized trials.

The authors analyzed data from 52 randomized placebo-controlled trials (4,893 adults) testing acetaminophen, nonsteroidal antiinflammatory drugs, or selective cyclooxygenase-2 inhibitors given in conjunction with morphine after surgery. The median of the average 24-h morphine consumption in controls was 49 mg (range, 15-117 mg); it was significantly decreased with all regimens by 15-55%. There was evidence of a reduction in pain intensity at 24 h (1 cm on the 0- to 10-cm visual analog scale) only with nonsteroidal antiinflammatory drugs. Nonsteroidal antiinflammatory drugs also significantly reduced the incidence of nausea/vomiting from 28.8% to 22.0% (number needed to treat, 15) and of sedation from 15.4% to 12.7% (number needed to treat, 37) but increased the risk of severe bleeding from 0% to 1.7% (number needed to harm, 59). Selective cyclooxygenase-2 inhibitors increased the risk of renal failure in cardiac patients from 0% to 1.4% (number needed to harm, 73). A decrease in morphine consumption is not a good indicator of the usefulness of a supplemental analgesic. There is evidence that the combination of nonsteroidal antiinflammatory drugs with patient-controlled analgesia morphine offers some advantages over morphine alone.

Acetaminophen↗
PubMed1990

Arm muscle activation for static forces in three-dimensional space.

1. Muscle activity was related to the direction of a static force at the human wrist. For each muscle the force direction of maximal activity and the directional tuning characteristics were determined. 2. Electromyographic (EMG) activity was recorded from nine superficial elbow and/or shoulder muscles while subjects held the right arm stationary in one of six postures. The direction of the force at the wrist was varied in two orthogonal planes. In each experiment a cable was attached to the subject's wrist, and a constant force magnitude was applied in various directions with the use of a pulley system. 3. The relationship between the averaged EMG level and the force direction was described for each muscle, in each posture, and in each plane. The EMG data were fit with a nonlinear, multiple cosine function, which allowed the identification of one, two, or sometimes three separate cosine peaks. 4. Two-cosine functions often provided the best fit to the EMG data. All nine muscles were best fit with a two-cosine function in at least two of the six postures. Four of the muscles had a second peak of activity in more than one-half of the experimental situations. The second peak was often in a direction that was nearly opposite the direction of the first peak and represented a negative contribution to the total force produced at the wrist ("coactivation"). We suggest that multimodal directional tuning results from the convergence of multiple sources of descending signals onto motoneurons. 5. The mechanical actions of nine elbow and/or shoulder muscles were estimated with the use of published data from a cadaver study by Wood and co-workers. Postural changes in the mechanical actions of muscles were substantial. A 45 degrees rotation of the shoulder, for example, might cause a 30-50 degrees change in the direction of force at the wrist that could be produced by the contraction of a given muscle. The magnitude of these postural changes suggests that arm position is an important determinate of EMG patterns. 6. Postural changes in the direction of maximal EMG activity usually paralleled the postural changes in mechanical pulling direction. Postural changes in EMG amplitudes usually covaried with postural changes in mechanical advantage. 7. The posterior deltoid (PD) was an exception to the general rule of covariation of mechanical actions and EMG activities. Instead of reflecting the muscle's mechanical action, the EMG activity of the PD closely resembled the EMG activity of the medial deltoid (MD).(ABSTRACT TRUNCATED AT 400 WORDS)

Arm↗
PubMed1998

[Multimodal therapy of tumors of the upper gastrointestinal tract].

Adjuvant and neoadjuvant therapeutic principles have in recent years received increasing attention in the management of patients with carcinoma of the upper gastrointestinal tract. A series of randomized prospective trials has demonstrated that adjuvant postoperative radiation or chemotherapy does not result in a convincing survival advantage after complete tumor resection in gastric or esophageal cancer. The available data on the role of neoadjuvant preoperative therapy in these patients as yet permit no conclusion. While neoadjuvant therapy may reduce the tumor mass in a substantial portion of patients, a series of randomized controlled trials has shown that, compared to primary resection, a multimodal approach does not result in a survival benefit in patients with loco-regional, i.e. potentially resectable, tumors. In contrast, in patients with locally advanced tumors, i.e. tumors for which complete removal with primary surgery appears unlikely, neoadjuvant therapy increases the chance for complete tumor resection on subsequent surgery. However, only patients with objective histopathologic response to preoperative therapy appear to benefit from this approach. Compared to preoperative chemotherapy alone, combined radio-chemotherapy increases the rate of response, particularly in squamous cell esophageal cancer, but may also increase postoperative morbidity and mortality. Neoadjuvant therapy should therefore currently only be performed in experienced centers within the context of prospective clinical trials. The identification of factors that would allow prediction of response to neoadjuvant or adjuvant therapy is the focus of ongoing studies.

Adenocarcinoma↗
PubMed2002

A 10-year review of quality improvement monitoring in pain management: recommendations for standardized outcome measures.

Quality measurement in health care is complex and in a constant state of evolution. Different approaches are necessary depending on the purpose of the measurement (e.g., accountability, research, improvement). Recent changes in health care accreditation standards are driving increased attention to measurement of the quality of pain management for improvement purposes. The purpose of this article is to determine what indicators are being used for pain quality improvement, compare results across studies, and provide specific recommendations to simplify and standardize future measurement of quality for hospital-based pain management initiatives. Pain management quality improvement monitoring experience and data from 1992 to 2001 were analyzed from 20 studies performed at eight large hospitals in the United States. Hospitals included: the University of Wisconsin Hospital and Clinics, Madison; Texas Medical Center, Houston; McAllen Medical Center, McAllen, TX; San Francisco General Hospital, San Francisco; Rush-Presbyterian-St. Luke's Medical Center and Northwestern Memorial Hospital, Chicago, IL; Memorial Sloan Kettering Cancer Center, New York; and Kaiser Sunnyside Medical Center of Kaiser Permanente Northwest, Clackamas, OR. Analyses of data led to consensus on six quality indicators for hospital-based pain management. These indicators include: the intensity of pain is documented with a numeric or descriptive rating scale; pain intensity is documented at frequent intervals; pain is treated by a route other than intramuscular; pain is treated with regularly administered analgesics, and when possible, a multimodal approach is used; pain is prevented and controlled to a degree that facilitates function and quality of life; and patients are adequately informed and knowledgeable about pain management. Although there are no perfect measures of quality, longitudinal data support the validity of a core set of indicators that could be used to obtain benchmark data for quality improvement in pain management in the hospital setting.

Activities of Daily Living↗
PubMed1995

[Image fusion of MRI and immunoscintigraphy with MAb-170 in ovarian tumors].

In recent years multimodality imaging achieved growing importance. It is mostly performed by means of quite expensive software and hardware solutions. In the present pilot study a simple and low-cost procedure was developed to achieve image fusion in the pelvis. The image data of immunoscintigraphy (SPECT) and MRI were transferred to a personal computer and combined by standard software for image manipulation. The results in eleven patients with space-occupying lesions in the pelvis showed that adequate anatometabolic slices could be achieved. The results show a tendency to increased specificity and precision of multimodality imaging in comparison with SPECT and MRI alone. In conclusion, the low-cost solution, as developed by us, is feasible in clinical practice. Its results are reliable in clinical decision making.

Adult↗
PubMed2006

Maternal dietary antigen avoidance during pregnancy or lactation, or both, for preventing or treating atopic disease in the child.

BACKGROUND: Some breastfed infants with atopic eczema benefit from elimination of cow milk, egg, or other antigens from their mother's diet. Maternal dietary antigens are also known to cross the placenta. OBJECTIVES: To assess the effects of prescribing an antigen avoidance diet during pregnancy or lactation, or both, on maternal and infant nutrition and on the prevention or treatment of atopic disease in the child. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2006) and contacted researchers in the field. SELECTION CRITERIA: All randomized or quasi-randomized comparisons of maternal dietary antigen avoidance prescribed to pregnant or lactating women. We excluded trials of multimodal interventions that included manipulation of the infant's diet other than breast milk or of nondietary aspects of the infant's environment. DATA COLLECTION AND ANALYSIS: We extracted data from published reports, supplemented by additional information received from the trialists we contacted. MAIN RESULTS: The evidence from four trials, involving 334 participants, does not suggest a protective effect of maternal dietary antigen avoidance during pregnancy on the incidence of atopic eczema during the first 18 months of life. Data on allergic rhinitis or conjunctivitis, or both, and urticaria are limited to a single trial each and are insufficient to draw meaningful inferences. Longer-term atopic outcomes have not been reported. The restricted diet during pregnancy was associated with a slightly but statistically significantly lower mean gestational weight gain, a nonsignificantly higher risk of preterm birth, and a nonsignificant reduction in mean birthweight.The evidence from one trial, involving 26 participants, did not observe a significant protective effect of maternal antigen avoidance during lactation on the incidence of atopic eczema during the first 18 months.One crossover trial involving 17 lactating mothers of infants with established atopic eczema found that maternal dietary antigen avoidance was associated with a nonsignificant reduction in eczema severity. AUTHORS' CONCLUSIONS: Prescription of an antigen avoidance diet to a high-risk woman during pregnancy is unlikely to reduce substantially her child's risk of atopic diseases, and such a diet may adversely affect maternal or fetal nutrition, or both. Prescription of an antigen avoidance diet to a high-risk woman during lactation may reduce her child's risk of developing atopic eczema, but better trials are needed. Dietary antigen avoidance by lactating mothers of infants with atopic eczema may reduce the severity of the eczema, but larger trials are needed.

Allergens↗
PubMed1999

Does debulking improve survival rate in advanced-stage retroperitoneal embryonal rhabdomyosarcoma?

UNLABELLED: BACKGROUND, METHODS, AND PURPOSE: The authors examined demographic and clinical features, therapy, and outcome of patients with advanced (group III or IV) rhabdomyosarcoma (RMS) of the retroperitoneum and nongenitourinary pelvis treated in the Intergroup Rhabdomyosarcoma Study Group (IRSG) III (1984 to 1991, n = 41) or IV pilot (1987 to 1991, n = 53) studies to assess the role of initial debulking surgery. RESULTS: Ninety-four patients with retroperitoneal primary tumors and gross locoregional residual tumor (group III, n = 53) or metastatic disease (group IV tumors, n = 41) were treated with combination chemotherapy (ie, vincristine, dactinomycin, and cyclophosphamide with or without other agents plus radiation therapy, RT) after biopsy only or subtotal resection. These retroperitoneal tumors usually were invasive (T2, 76%). Most patients were younger than 10 years of age (n = 69, 73%), the male to female ratio was 1.4, and tumors usually were embryonal (n = 64, 68%). Overall 4-year failure-free survival (FFS) was 50%; survival was 60%. Survival rate was better for girls (4-year survival rate, 75% v49% for boys; P = .05) and was not significantly different for patients treated in IRS-III (66%) or IRS-IV pilot (52%). However, it was better for patients with embryonal versus alveolar or undifferentiated tumors (4-year survival rate, 70% v 42%; P = .002). In adolescents, RMS is different from that seen in children less than 10 years old; most cases are alveolar or undifferentiated (16 of 29, 55%). Surgery for most (21 of 24) patients with alveolar tumors comprised biopsy only. By contrast, of 64 patients with embryonal tumors, 39 (61%) underwent biopsy only, whereas 25 (39%) had debulking surgery. Patients whose tumors were debulked fared better than those whose tumors underwent biopsy only (4-year FFS rate, 72% v48%; P = 0.03). Patients with group IV embryonal tumors fared unexpectedly better than those with group IV alveolar or undifferentiated tumors (70% versus 42% 4-year survival rate, P < .05), and patients less than 10 years of age with group IV embryonal tumors had 4-year survival rate of 77%, indicating the importance of the biology of these tumors. CONCLUSIONS: Multimodal therapy, including multiagent chemotherapy plus RT, appears to improve survival rate in patients with advanced embryonal RMS arising in the retroperitoneum. These data suggest that debulking tumors of embryonal histology improves outcome further. This approach will be assessed in IRSG V.

Adolescent↗
PubMed2004

Population of linear experts: knowledge partitioning and function learning.

Knowledge partitioning is a theoretical construct holding that knowledge is not always integrated and homogeneous but may be separated into independent parcels containing mutually contradictory information. Knowledge partitioning has been observed in research on expertise, categorization, and function learning. This article presents a theory of function learning (the population of linear experts model--POLE) that assumes people partition their knowledge whenever they are presented with a complex task. The authors show that POLE is a general model of function learning that accommodates both benchmark results and recent data on knowledge partitioning. POLE also makes the counterintuitive prediction that a person's distribution of responses to repeated test stimuli should be multimodal. The authors report 3 experiments that support this prediction.

Analysis of Variance↗
PubMed2002

The accuracy and reliability of radiographic methods for the assessment of marginal bone level around oral implants.

OBJECTIVES: To determine the accuracy and reliability of radiographic methods for assessment of the marginal bone level around oral implants in human cadavers. METHODS: In three human cadavers two implants were placed according to the Instruction Manual for the Brånemark System. One implant was installed in the canine and one in the premolar region of the left mandible. For each implant, conventional and digital intra-oral paralleling radiography were performed. Digital images were printed with a Kodak 1200 Distributed Medical Imaging printer on blue transparent film, glossy and plain paper. Furthermore, digital scanographic, panoramic and tomographic images were taken with the Cranex Tome multimodal X-ray unit and printed on Agfa Drystar TM 1 B transparent films. All images were evaluated by five dental specialists. Data were statistically compared with real measurements of the marginal bone level on the human cadavers, performed by the same group of observers. Intra- and inter-observer variability were determined. RESULTS: Digital intra-oral images on glossy paper showed the smallest absolute difference between real and measured bone level, followed by digital intra-oral images on film and on plain paper, conventional intra-oral images on analogue film, panoramic, scanographic and tomographic images on film. The difference between real and radiographic measurements was not statistically significant (P>0.05) for all radiographic techniques. Intra- and inter-observer reproducibility was high for all techniques. CONCLUSIONS: The selected imaging techniques showed an acceptable accuracy for peri-implant bone level measurements with an overall error of less than 0.5 mm. Intra-oral images showed the smallest absolute differences.

Alveolar Process↗
PubMed2003

Curative potential of multimodality therapy for locally recurrent rectal cancer.

OBJECTIVE: To assess the results of multimodality therapy for patients with recurrent rectal cancer and to analyze factors predictive of curative resection and prognostic for overall survival. SUMMARY BACKGROUND DATA: Locally recurrent rectal cancer is a difficult clinical problem, and radical treatment options with curative intent are not generally accepted. METHODS: A total of 394 patients underwent surgical exploration for recurrent rectal cancer. Ninety were found to have unresectable local or extrapelvic disease and 304 underwent resection of the recurrence. The latter patients were prospectively followed to determine long-term survival and factors influencing survival. RESULTS: Overall 5-year survival was 25%. Curative, negative resection margins were obtained in 45% of patients; in these patients a 5-year survival of 37% was achieved, compared to 16% (P <.001) in patients with either microscopic or gross residual disease. In a logistic regression analysis, initial surgery with end-colostomy and symptomatic pain (both univariate) and increasing number of sites of the recurrent tumor fixation in the pelvis (multivariate) were associated with palliative surgery. Overall survival was significantly decreased for symptomatic pain (P <.001) and more than one fixation (P =.029). Survival following extended resection of adjacent organs was not different from limited resection (28% vs. 21%, P =.11). Patient demographics and factors related to the initial rectal cancer did not affect outcome. Perioperative mortality was only 0.3%, but significant morbidity occurred in 26% of patients, with pelvic abscess being the most common complication. CONCLUSIONS: This study demonstrates that many patients with locally recurrent rectal cancer can be resected with negative margins. Long-term survival can be achieved, especially for patients with no symptoms and minimal fixation of the recurrence in the pelvis, provided no gross residual disease remains.

Adult↗
PubMed1997

A lacertilian dorsal retinorecipient thalamus: a re-investigation in the old-world lizard Podarcis hispanica.

The aim of this work is to delineate the retinorecipient cell groups of the dorsal thalamus of lizards and to study some of the differential connections in order to help to understand the evolution of the visual system in tetrapods. Tract-tracing and immunohistochemical techniques were applied to the retinorecipient dorsal thalamus of the lizard Podarcis hispanica. The retina of Podarcis projects to four areas of the dorsal thalamus: nucleus ovalis (Ov), intergeniculate leaflet (IGL), dorsal lateral geniculate nucleus (GLD) and dorsolateral anterior nucleus (DLA). Nucleus ovalis shows a clear cell plate/neuropile organization and projects to the ventral thalamus. Thus, it seems to belong to the ventral rather than to the dorsal thalamus. The IGL contains large cells reactive for GABA and/or NPY immunohistochemistry. It is interconnected with the supra/retrochiasmatic hypothalamus and projects to the opposite thalamus and to the ipsilateral tectum. The caudal DLA, which lacks both GABA- and NPY-like immunoreactive cells, is reached by a few thin retinal fibers, although distal dendrites of DLA cells enter the GLD, suggesting an important retinal input. The DLA projects to the medial and dorsal telencephalic cortices. The GLD is the main retinorecipient thalamic structure that projects to the telencephalon. It shows a crude laminar organization in which cell plate neurons project to the ipsilateral pallial thickening, but it does not receive a descending projection from the visual telencephalon and thus differs from the GLD of other amniotic vertebrates. In the context of present knowledge, these results suggest that an IGL homologue is present in all tetrapods studied, whereas Ov seems to be restricted to diapsid vertebrates. Moreover, our data suggest that a unimodal visual projection to the telencephalon (arising from the GLD) first appeared in reptiles by segregation from a limbic (multimodal) thalamo-telencephalic pathway.

Animals↗