Retromuscular mesh and hernial sac technique in the reconstruction of 139 cases of large median incisional hernias: one institution's experience.

PURPOSE: Incisional hernia is the most common complication of laparotomy. Postoperative parietal defects tend to relapse, even after the most optimal surgical methods. The aim of this study was to present the effectiveness of an adapted retromuscular technique with prolene mesh and a hernial sac, in patients with large incisional median hernias. The reported results were obtained by our team after more than 15 years of experience. METHODS: This retrospective study included 139 consecutive cases of large median incisional hernias operated on using a retromuscular mesh and hernial sac technique. The cross-sectional diameter of incisional hernias was larger than 10 cm, being classified in the W3 group, according to the European Hernia Society classification. RESULTS: The study included 83 females (59.71%) and 56 males (40.29%) with a median age of 62.4 ± 16.6 years and an average body mass index of 32.4 ± 7.6 kg. The hernia was supraumbilically located in 54 cases, subumbilically in 61 cases, and supra- and subumbilically in 24 cases. Postoperative complications were recorded in eight cases (5.75%): one case with a hematoma in the right abdominal muscle sheath; five cases with supra-aponeurotic seromas; two cases with skin necrosis and one with a mesh infection. Recurrence occurred in seven cases (5.03%): four cases in the first 2 years postoperatively and three cases in the third year after surgery. CONCLUSIONS: The retromuscular technique with prolene mesh and a hernial sac is an effective method of restoring the integrity of the abdominal wall in large median incisional hernias with low rates of morbidity and recurrence.

Microsatellite instability and hMLH1 promoter hypermethylation in Richter's transformation of chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is an indolent B cell non-Hodgkin lymphoma (NHL) that may transform into diffuse large B cell lymphoma (DLBL). This transformation is referred to as Richter's syndrome or transformation. To analyze whether microsatellite instability (MSI) and DNA mismatch repair defects are associated with Richter's transformation, we have performed microsatellite analysis, mutational analysis of hMLH1 and hMSH2 genes and methylation status analysis of CpG island of the hMLH1 promoter on serial biopsy specimens from 19 patients with CLL. Ten cases of CLL showed no histologic alteration in the second biopsy, and nine cases of CLL underwent morphologic transformation to DLBL in the second biopsy. Using eight microsatellite loci, high level of MSI was associated with Richter's transformation in four cases of CLL, but none of the CLLs displayed this level of MSI without transformation. Mutations of the hMLH1 or hMSH2 genes were not detected in any of the lymphoma samples. In five cases of Richter's transformation the hMLH1 promoter was hypermethylated in both CLL and DLBL samples. Hypermethylation of the hMLH1 promoter associated with high-level of MSI in four cases, and low-level of MSI in one case. These results suggest that in certain cases of Richter's transformation the DNA mismatch-repair defect-initiated genetic instability may play a role in tumor progression.

Relationship between the mutational status of VH genes and pathogenesis of diffuse large B-cell lymphoma in Richter's syndrome.

Patients with chronic lymphocytic leukemia (CLL) may develop diffuse large B-cell lymphoma (DLBL), also known as Richter's syndrome. Mutational status of immunoglobulin (Ig) heavy-chain variable region (VH) genes have prognostic impact in CLL. Patients with mutated VH genes have a stable disease, whereas patients with unmutated VH gene have more aggressive disease. The mutational status of CLLs that transform to DLBL is unknown. To reveal whether Richter's syndrome occurs in CLLs with mutated or unmutated VH genes, we have performed mutational analysis on serial specimens from eight patients. CLL and DLBL tumorclones were identical in five cases and they were different in three cases. Six CLLs expressed unmutated and two cases expressed mutated VH genes. In five of the six unmutated CLLs, the DLBL clones evolved from CLL tumorclones and the VH genes expressed by DLBLs were also unmutated. In one unmutated and two mutated CLLs, the DLBLs expressed mutated VH genes, but in these three cases the DLBL tumorclones developed as independent secondary neoplasm. These results suggest that Richter's syndrome may develop in both mutated or unmutated CLLs, but clonal transformation of CLL to DLBL occur only in the unmutated subgroup of CLL.

Low extracellular magnesium unmasks N-methyl-D-aspartate-mediated graft-host connections in rat neocortex slice preparation.

The main purpose of this study was to investigate the role of N-methyl-D-aspartate receptors in host-graft synaptic transmission in the neocortex. The effects of low extracellular magnesium, the glutamate agonist N-methyl-D-aspartate and N-methyl-D-aspartate antagonists on the synaptic activation of connections between embryonic neocortical graft tissue and the surrounding host tissue were studied in 17 perfused slices of rat neocortex. In standard artificial cerebrospinal fluid, stimulation of the host white matter evoked field potentials in four of 17 grafts. However, in Mg(2+)-free medium, the same stimulation evoked field potentials in an additional six grafts, with significant increases in the mean duration of the evoked responses in the 10 responsive grafts. In five of these slices stimulation of the graft also evoked field potentials in the host tissue, suggesting reciprocal interaction between graft and host. Simultaneous extracellular recordings from graft and host tissues in Mg(2+)-free medium showed that spontaneous epileptiform discharges developed in the graft and host tissue synchronously. In Mg(2+)-free medium, application of N-methyl-D-aspartate induced a shift of the baseline with superimposed epileptiform discharges in both graft and host. Application of the non-competitive N-methyl-D-aspartate antagonist ketamine and the competitive antagonist D,L-2-amino-5-phosphonovaleric acid attenuated or reversibly blocked both the spontaneous epileptiform discharges and the evoked field potentials. Our data provides evidence that N-methyl-D-aspartate receptors are present at synapses created between fetal graft and host neocortex, and that the N-methyl-D-aspartate-activated receptor-channel complex plays an active role in mediating excitatory synaptic transmission in host-graft circuitry.

Bilateral frontal cortical contusion in rats: behavioral and anatomic consequences.

The purpose of this study was to develop a bilateral model of frontal cortical contusion in the rat that would demonstrate reproducible deficits typically found after frontal lobe injury in humans. We used a pneumatically controlled cortical impactor to create bilateral contusions of the medial prefrontal cortex (PFC) in adult male Sprague-Dawley rats. Cognitive, neurologic, physiologic, and histopathologic measures were used to evaluate changes caused by the injury. The cognitive task employed the Morris water maze (MWM). Contused rats performed worse than sham-operated controls on measures of time taken to find a submerged platform, distance to the platform, and swim strategy. Neurologic measures revealed impairments of tongue mobility and transient deficits of forelimb placing. Body weights of the contused rats were chronically reduced with respect to controls, indicating that cortical contusion produces disruption in homeostasis. All rats given bilateral PFC contusions developed marked necrotic cavities at the site of impact. The borders surrounding the cavities were heavily lined with astrocytes and ameboid microglia. There was subcortical gliosis in the medial caudate that extended throughout the rostral-caudal length of the caudate-putamen and into the mediodorsal (MD) and ventrolateral (VL) nuclei of the thalamus. The thalamus was also the site of distal transneuronal degeneration. In both the MD and the VL, there was significant neuronal loss in the contused rats as compared with sham-operated controls. This method of bilateral cortical contusion demonstrates clear, reproducible results that would be required for the development of future pharmacologic therapies designed to promote functional recovery.

Blood-brain barrier breakdown and edema formation following frontal cortical contusion: does hormonal status play a role?

The present experiment was designed to evaluate and correlate the time course of blood-brain barrier (BBB) integrity and cerebral edema in adult male rats given medial frontal cortex contusions. The effect of sex hormones on BBB integrity in the same injury model was also examined, because previous work has shown that progesterone can reduce cerebral edema (Roof et al., 1993). BBB breakdown was assessed by Evans blue extravasation and albumin immunostaining while edema formation was measured by the wet weight dry weight technique. These processes were examined beginning 2 h and continuing up to 10 days after injury. Our findings show that medial frontal contusion in rats produces changes in cerebral water content and opening of the BBB that endures at least 7 days postinjury. Although pseudopregnancy has been shown to reduce cerebral edema at day 1 postinjury, we did not find any evidence that this hormonal state is associated with BBB repair.

Acute ethanol administration reduces the cognitive deficits associated with traumatic brain injury in rats.

The present study was designed to determine whether a low dose of acute ethanol administration could attenuate cognitive deficits associated with traumatic brain injury. Adult male rats received oral administration of ethanol or drinking water 2 h prior to surgery to produce a blood ethanol concentration of 100 mg% and then received bilateral contusion injuries of the medial prefrontal cortex. Seven days after surgery, the rats began 10 days of testing for acquisition of spatial localization in the Morris water maze where they were required to find a hidden platform to escape from the water. The results indicate that the rats given ethanol at the time of injury later spent significantly less time searching for the hidden platform than their water-treated counterparts. On a memory probe test given on the final day of testing, in which the platform was removed from the pool, rats given the ethanol spent more time in the area where the platform had been located indicating that they learned its location better than the lesion/water controls. In addition, acute ethanol treatment reduced some of the histopathology that typically occurs following severe contusion of the medial frontal cortex but did not attenuate post-traumatic formation of edema. These results indicate that acute ethanol intoxication can reduce the severity of cognitive impairments caused by contusive traumatic brain injury and support the contention that there is a dose-response relationship of acute ethanol intoxication in the setting of traumatic brain injury.

Visualization of outgrowing axons of grafted neurons by anterograde labelling with Phaseolus vulgaris leucoagglutinin in the motor cortex of the rat.

Fetal cerebral cortical tissue was transplanted into an aspirated lesion cavity made in the sensorimotor cortex of adult rats. Ten weeks after grafting, outgrowing fibers from the graft were visualized by an anterograde tracing technique using Phaseolus vulgaris leucoagglutinin (PHA-L). It was demonstrated that the efferent fibers grew into the neighboring host cortical tissue, the corpus callosum and in some cases approached caudate/putamen. Characteristic axon arborization with abundant boutons were found in the host cortical tissue, but only in close vicinity to the grafts. It is concluded that the PHA-L anterograde tracing technique can be a useful tool to assess the degree of anatomical integration of the transplants into the host tissue.

Intraseptal injections of 192 IgG saporin produce deficits for strategy selection in spatial-memory tasks.

The involvement of the cholinergic septohippocampal system in strategies used to reach a spatial goal was examined by functionally inactivating this system with infusions of 192 IgG saporin, a potent cholinergic immunotoxin. Rats were initially trained on a win-shift radial arm maze (RAM) task and then given injections of either 192 IgG saporin (LES) or saline vehicle (CON) into the medial septum and vertical limb of the diagonal band. Rats were then retested postoperatively on the RAM to assess whether allocentric spatial strategies used to solve the task were impaired. The results indicated that injections of 192 IgG saporin into the septum of rats produced deficits in allocentric strategies used to locate the spatial goal when retested. In addition, place and response learning was also examined in a modified version of the Morris water maze task. In this task, rats with cholinergic lesions were mildly impaired in their ability to learn a place response. In order to clarify further whether rats may have been relying on allocentric or egocentric learning strategies to locate the platform, a probe trial was given on the final test day in which the visible platform was moved to a new location. Control rats swam either to the new platform location or the old platform location indicating the use of both an allocentric and egocentric response. However, rats with the cholinergic septal lesions swam to the new platform location indicating an egocentric response. Taken together, these results suggest that selective cholinergic lesions of the septum produce deficits in spatial strategies used to locate a spatial goal.

Regional changes in the expression of neurotrophic factors and their receptors following acute traumatic brain injury in the adult rat brain.

We have analyzed the effect of severe traumatic brain injury (TBI) on the levels of mRNA expression of neurotrophic factors (NTFs): brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), ciliary neurotrophic factor (CNTF) and their respective receptors: trkB, trkA and CNTFRalpha. The expression was examined in the region of the lesion as well as a region remote from the lesion at 12, 24, and 36 h following the injury. Our data suggest that after the brain injury, the expression of NGF and BDNF mRNAs were early, transiently and significantly upregulated while that of CNTF was a slow and less amplified response in both areas of the brain. We also found that trkA mRNA expression was only upregulated significantly in the remote area; trkB mRNA showed no significant change in either area except an upregulation at 12 h in the remote area. CNTFRalpha was downregulated significantly by 24-36 h in the lesion area and by 24 h in the remote area. These changes suggest that TBI regulates the expression of NTFs and their receptors. These alterations in expression may be involved in modulating the neuronal response after brain injury.

Mature but not fetal or neonatal rat superior cervical ganglion transplants survive in the cortex of adult rats.

The transplantation of catecholaminergic tissues is a possible therapy for parkinsonism. Central nervous tissue is suitable for transplantation only in the immature stage, whereas peripheral nervous tissue can also be transplanted when mature. The present study compares the development of fetal (17-20 embryonic day, E17-20), neonatal (1-3 postnatal day, P1-3) and mature (5-6-week-old) rat superior cervical ganglia after transplantation into the cerebral cortex of adult rats. The mature transplants survived in greater proportion and preserved their structural characteristics, although a considerable proportion of the neurons died. The perinatal transplants only survived sporadically, decreased in size and the surviving remnants failed to display a structure comparable to the adult ganglion in situ. Thus, the use of adult donors is not only a possibility but a necessity when superior cervical ganglion (probably any ganglion) is transplanted. This principle is radically different from that seen in the case of central nervous tissues, and can be understood by the analysis of the time curves of cell proliferation and programmed cell death (apoptosis) observed during the perinatal development of sympathetic ganglia.

Proliferation of Bergmann-glia in the developing rat cerebellum.

Mitotic cells in the ganglionic layer of the infant rat cerebellum were studied between 3 to 12 postnatal days. The connection of these cells with the radial glial fibers of the primitive molecular layer could be established. On this basis it was assumed that the mitotic cells studied were immature Bergmann-glial cells whose proliferative activity seemed to continue even after the formation of their characteristic radial fibers. This phenomenon might offer an explanation for the divergent views on the generation time of Bergmann-glia.

Mosaicism of the ventricular layer as the developmental basis of neocortical columnar organization. A 3H-thymidine autoradiographic study in newborn mice.

The ratio and local distribution of intensely and weakly labelled neurons as compared with unlabelled neurons were studied in newborn mice by means of autoradiography using 3H-thymidine injected at various embryonic ages. The distribution and migrational properties of intensely labelled neurons suggest that cells contributing to any given cortical layer are not generated simultaneously but in smaller units that correspond to cortical microcolumns. This implies a mosaicity in the genetic potential of the ventricular germinative layer.

Branching-pattern analysis of the dendritic arborization in the thalamic nuclei of the rat brain.

We investigated the dendritic patterns of rapid Golgi-impregnated, highly similar multipolar neurons from two functionally different thalamic regions of the rat brain: two dorsal nuclei (the nucleus laterodorsalis thalami, pars dorsomedialis and the nucleus laterodorsalis thalami, pars ventrolateralis), and two ventral nuclei (the nucleus ventrolateralis thalami and the nucleus ventromedialis thalami). The analysis involved conventional morphometric parameters (height and size) and a new parameter derived from graph theory, the relative imbalance (RI), derived from the branching patterns of the dendrites, which permits quantitative characterization of the dendritic arborization of a neuron. On this basis, neurons can be grouped into three fundamentally different types: type A, or highly-polarized (imbalanced) neurons (RI values close to 1); type B, or medium-polarized neurons (RI values around 0.5); and type C, or balanced neurons with low polarization (RI values close to 0). The orientations of the dendritic arbor, and thus the receptive fields, of the dorsal and ventral thalamic neurons, were mutually perpendicular. The H and S values indicated that the neurons in the dorsal and ventral thalamic nuclei differed significantly. However, their RI values demonstrated that they were similar neurons of type B. Our data reveal that 1 ) the dendritic arbor cannot be reliably characterized purely on the basis of height and size, and 2) RI is a valuable morphometric parameter that identifies the true nature of the dendritic arborization.

[Differentiation of astroglial cells of the cerebellar cortex in the postnatal development of the rat: a morphological and histochemical study]. / Differentsirovka astroglial'nykh kletok kory mozzhechka v postnatal'nom razvitii krysy: morfologicheskoe i gistokhimicheskoe issledovanie.

The morphological autoradiographic and cytospectrophotometric analysis of proliferation and differentation of the cerebellar cortex astroglial cells has been carried out during the rat early postnatal development. The proliferating astroglial cells constitute a major part of the whole cell population of the internal granular layer during the first week. It was proved by means of double labelling (3H- and 14C-thymidine) that these cells synthesize DNA and divide repeatedly, their division proceeding without preliminary morphological dedifferentiation, i. e. with the preservation of plasmatic processes. A suggestion is put forward that the precursors of the cerebellar cortex astroglial cells under study take their origin from the subependymal zone during the prenatal development. The results obtained allow to identify the proliferating glial cells as the Bergman's glia.

Stellar and primordial nucleosynthesis of 7Be: measurement of 3He(alpha,gamma)7Be.

The 3He(alpha,gamma)7Be reaction presently represents the largest nuclear uncertainty in the predicted solar neutrino flux and has important implications on the big bang nucleosynthesis, i.e., the production of primordial 7Li. We present here the results of an experiment using the recoil separator ERNA (European Recoil separator for Nuclear Astrophysics) to detect directly the 7Be ejectiles. In addition, off-beam activation and coincidence gamma-ray measurements were performed at selected energies. At energies above 1 MeV a large discrepancy compared to previous results is observed both in the absolute value and in the energy dependence of the cross section. Based on the available data and models, a robust estimate of the cross section at the astrophysical relevant energies is proposed.