Sclerotic Regions Research Articles

Cation‐Chloride Cotransporters and GABA‐ergic Innervation in the Human Epileptic Hippocampus

Intracellular chloride concentration, [Cl(-)](i), determines the polarity of GABA(A)-induced neuronal Cl(-) currents. In neurons, [Cl(-)](i) is set by the activity of Na(+), K(+), 2Cl(-) cotransporters (NKCC) such as NKCC1, which physiologically accumulate Cl(-) in the cell, and Cl(-) extruding K(+), Cl(-) cotransporters like KCC2. Alterations in the balance of NKCC1 and KCC2 activity may determine the switch from hyperpolarizing to depolarizing effects of GABA, reported in the subiculum of epileptic patients with hippocampal sclerosis. We studied the expression of NKCC (putative NKCC1) and KCC2 in human normal temporal neocortex by Western blot analysis and in normal and epileptic regions of the subiculum and the hippocampus proper using immunocytochemistry. Western blot analysis revealed NKCC and KCC2 proteins in adult human neocortical membranes similar to those in rat neocortex. NKCC and KCC2 immunolabeling of pyramidal and nonpyramidal cells was found in normal and epileptic hippocampal formation. In the transition between the subiculum with sclerotic regions of CA1, known to exhibit epileptogenic activity, double immunolabeling of NKCC and KCC2 revealed that approximately 20% of the NKCC-immunoreactive neurons do not express KCC2. In these same areas some neurons were distinctly hyperinnervated by parvalbumin (PV) positive hypertrophic basket formations that innervated mostly neurons expressing NKCC (74%) and to a lesser extent NKCC-immunonegative neurons (26%). Hypertrophic basket formations also innervated KCC2-positive (76%) and -negative (24%) neurons. The data suggest that changes in the relative expression of NKCC1 and KCC2 in neurons having aberrant GABA-ergic hyperinnervation may contribute to epileptiform activity in the subicular regions adjacent to sclerotic areas of the hippocampus.

GAT1 and GAT3 expression are differently localized in the human epileptogenic hippocampus

The gamma amino butyric acid (GABA) transporters GAT-1 and GAT-3 were localized by immunohistochemistry in hippocampi removed for the control of medically intractable temporal lobe epilepsy (TLE). The study aimed to determine the relationship of GABA transporter expression to known patterns of hippocampal hyperexcitability and extracellular GABA levels. GAT-1 was localized in axon terminals and small neuronal cell bodies, and in non-sclerotic hippocampi was strongly expressed throughout all regions of the hippocampal formation. In the epileptogenic hippocampus exhibiting Ammon's horn sclerosis, immunoreactivity was reduced in the sclerotic regions CA3 and CA1, and around the cell bodies of dentate granule cells, but was increased along granule cell dendrites. GAT-3 was weakly expressed, if at all, in non-sclerotic hippocampi, but more prominently expressed in sclerotic hippocampi. GAT-3 expression was confined to cells resembling protoplasmic astrocytes, which were located in regions of relative neuronal sparing such as the dentate gyrus and hilus of the sclerotic hippocampus. The reduction in GAT-1 around granule cells in the sclerotic hippocampus could explain the prolonged GABA responses in this region. The loss of GAT-1 (a marker of GABAergic terminals) would also suggest a reduced GABAergic input to the granule cells, thus facilitating hyperexcitability. The increased GAT-3 expression in astrocytes in regions of relative neuronal sparing in the sclerotic hippocampus may be related to the overall low levels of extracellular GABA observed in the sclerotic hippocampus and their increased excitability.

Pathophysiologic Implications of Reduced Podocyte Number in a Rat Model of Progressive Glomerular Injury

Changes in podocyte number or density have been suggested to play an important role in renal disease progression. Here, we investigated the temporal relationship between glomerular podocyte number and development of proteinuria and glomerulosclerosis in the male Munich Wistar Fromter (MWF) rat. We also assessed whether changes in podocyte number affect podocyte function and focused specifically on the slit diaphragm-associated protein nephrin. Age-matched Wistar rats were used as controls. Estimation of podocyte number per glomerulus was determined by digital morphometry of WT1-positive cells. MWF rats developed moderate hypertension, massive proteinuria, and glomerulosclerosis with age. Glomerular hypertrophy was already observed at 10 weeks of age and progressively increased thereafter. By contrast, mean podocyte number per glomerulus was lower than normal in young animals and further decreased with time. As a consequence, the capillary tuft volume per podocyte was more than threefold increased in older rats. Electron microscopy showed important changes in podocyte structure of MWF rats, with expansion of podocyte bodies surrounding glomerular filtration membrane. Glomerular nephrin expression was markedly altered in MWF rats and inversely correlated with both podocyte loss and proteinuria. Our findings suggest that reduction in podocyte number is an important determinant of podocyte dysfunction and progressive impairment of the glomerular permselectivity that lead to the development of massive proteinuria and ultimately to renal scarring.

Sclerosing lesions of the breast

Sclerosing lesions of the breast often mimic invasive carcinoma at the gross and microscopic levels and can pose a significant diagnostic challenge for surgical pathologists. This brief review is devoted to the histopathological characterization of 2 such sclerosing lesions of the breast: radial scars and sclerosing nipple adenomas. Microscopically, these lesions show similar morphological features: a zonal architectural pattern consisting of a central sclerotic region with entrapped distorted glands and a corona-like peripheral region with associated nonproliferative and proliferative fibrocystic changes. Important diagnostic features of these lesions are highlighted and contrasted with those of invasive carcinoma.

Macrophage accumulation within the cap of carotid atherosclerotic plaques is associated with the onset of cerebral ischemic events

Purpose: Macrophage accumulation is associated with aortic and coronary plaque instability. The macrophage content of carotid plaques removed at carotid endarterectomy (CE) was assessed, and the relevance to the onset of ipsilateral cerebral ischemic events (CIE) was examined. Methods: Carotid plaques from patients undergoing CE were examined (group I, symptomatic stenoses, n = 28; group II, high-grade asymptomatic stenosis, n = 7). The plaques were stained with monoclonal antimacrophage antibody (HAM56), and the interval since the last CIE was recorded. The percentage area of the cap, shoulder, and entire sclerotic region was quantified by computerized planimetry. Results: The macrophage content of the cap, shoulder, and sclerotic region in all 35 plaques was 1.14% (interquartile range, 0.56 to 3.86), 1.03% (0.51 to 2.15), and 0.49% (0.27 to 0.63), respectively (cap vs sclerotic, P < .01; shoulder vs sclerotic, P < .01; cap vs shoulder, P = .23). In 18 plaques that were removed less than 180 days after the last CIE, the macrophage content of the cap, shoulder, and entire sclerotic region was 2.41% (0.95 to 4.81), 0.83% (0.40 to 2.52), and 0.53% (0.38 to 0.71), respectively (cap vs sclerotic, P = .01; cap vs shoulder, P = .01). The content in the cap of these plaques was greater than in plaques removed more than 180 days after symptoms, or asymptomatic plaques (n = 17; 0.62% [0.44 to 1.25], P = .01). The cap macrophage content was inversely related to the time since the last CIE (r = –0.414, P = .029). Conclusion: In patients requiring CE, macrophage accumulation was maximal within the cap of carotid plaques and greatest in plaques removed less than 180 days after the last CIE. These findings and the inverse relationship between macrophage content and the interval since symptoms support the hypothesis that macrophage accumulation is associated with plaque instability. (J Vasc Surg 1999;30:269-76.)

Lichen sclerosus: evidence that immunological changes occur at all levels of the skin

An immunohistochemical approach was used to characterize the inflammatory infiltrate in vulval lichen sclerosus, using monoclonal antibodies to CD3, CD4, CD8, CD68 and HLA-DR. Significant numbers of CD4 + and CD8 + lymphocytes were observed in the dermal band of inflammatory cells in approximately equal proportions. Less numerous CD4 + and CD8 + lymphocytes also occurred adjacent to the dermoepidermal junction and occasionally in the lower epidermis. Increased numbers of cells staining with the monocyte/macrophage marker CD68 were also present in the band of inflammatory cells as well as being scattered diffusely throughout the sclerotic region. Expression of HLA-DR in the lichen sclerosus specimens was increased within the inflammatory infiltrate and around blood vessels in the dermis. All the vulval lichen sclerosus specimens also demonstrated some HLA-DR expression around the keratinocytes, suggesting that these keratinocytes might be involved in antigen presentation. We also studied the expression of CD44 and its isoforms 3G5 (marker of V3), 8G5 (marker of V6), 3D2 (marker of V4/5) and IE8 (marker of V8/9). CD44 has been proposed to play a part in lymphocyte homing, cell-matrix interaction (particularly with hyaluronic acid), lymphocyte activation and malignant progression of certain tumours. The epidermis of the lichen sclerosus specimens appeared to demonstrate a greater intensity of staining with the pan-CD44 marker F10-44, and reduced staining with 3G5, 3D2 and IE8 compared with normal skin. Like normal skin, the dermis of the lichen sclerosus specimens did not demonstrate staining with 3G5, 3D2, 8G5 or 1E8, but did show staining with F10-44. However, the pattern of the dermal staining with F10-44 reflected the position of the inflammatory infiltrate and was sparse in the five sections where there was a prominent sclerotic zone, but increased in the three sections where there was a prominent band of inflammation cells. Our results demonstrate evidence of immunological changes at all levels of skin involved by lichen sclerosus, including the epidermis.

前十字靭帯再建術後のけい骨骨孔変化の検討

This study was designed to realize changes in the tibial tunnel regarded as the enlargement of the bone tunnel after anterior cruciate ligament reconstruction by bone-patellar tendon-bone autograft. The changes in the geometry of the tibial tunnel were measured radiographically during the immediate postoperative period, the period that sclerotic change occurred, and at around 1 year after surgery in 34 knees. At the level of the joint line, we measured the inner diameter of the tibial tunnel and the outer diameter that included the sclerotic region at the margin of the tunnel. We also measured the position of the tibial tunnel at AP and lateral view. Only 2 out of 34 knees showed an enlargement of the inner diameter greater than or equal to 2mm in width. In the other 32 knees, the main change was the thickening of the sclerotic region, ranging from 1.5 to 5mm, at the margin of bone tunnel. No significant relationship was seen between the thickening of the sclerosis and the position of tibial tunnel. These results suggest the possibility that the thickening of the sclerotic region may be regarded as the enlargement of the tibial tunnel.

Extracellular matrix 22-kDa protein interacts with decorin core protein and is expressed in cutaneous fibrosis.

A protein with an Mr of 22,000 was purified from bovine dermis. The amino acid sequence of the protein was identical to 22-kDa protein [Neame, P.J. et al. (1989) J. Biol. Chem. 264, 5474-5479] and showed highly homologous sequences to TRAMP (tyrosine rich acidic matrix protein) [Cronshaw, A.D. et al. (1993) Matrix 13, 255-266] and dermatopontin [Superti-Furga, A. et al. (1993) Genomics 17, 463-467]. The protein was proved to associate with decorin and a modified decorin with carboxymethylated cysteinyl residues, but not to assemble to hyaluronate or dermatan sulfate chains. The pyridylethylation of cysteinyl residues in the 22-kDa protein did not affect its binding activity to decorin or modified decorin. Immunohistochemical analyses revealed positive stains in endothelial cells and the periphery of collagen fibers in normal dermis but not in the fibroblasts in tissue. Collagen fibers in sclerotic regions of progressive systemic sclerosis were stained diffusely, suggesting that the 22-kDa protein increases in parallel to the accumulation of collagen in the disease. Western blotting analyses of extracts of cultured endothelial cells revealed a lower Mr protein than that from cultured fibroblasts, suggesting the presence of a molecule related to the 22-kDa protein.

Correlation between function and structure in "epileptic" human hippocampal tissue maintained in vitro.

Intracellular and extracellular recordings were obtained from the CA1 region and gyrus dentatus of human hippocampi that had been surgically removed for treatment of intractable seizures. Pathologic diagnoses were obtained, and electrophysiologic results were correlated with degree of principal cell loss (sclerosis) in the regions studied. Extracellular field potentials were absent or smaller in amplitude, with abnormal characteristics, in sclerotic regions. In all regions, regardless of the degree of sclerosis, individual pyramidal or granule cells could be penetrated. These neurons showed apparently normal electrophysiologic characteristics and intact excitatory synaptic input. No signs of hyperexcitability were observed.

Pathogenesis of interstitial fibrosis in chronic purine aminonucleoside nephrosis

A cellular and molecular approach was used to gain new insight into the pathogenesis of interstitial fibrosis in chronic purine aminonucleoside nephrosis (PAN) nephrosis. Thirty experimental rats (PAN rats) were given 15 mg/100 g body wt of i.p. PAN at time 0, followed by 4.3 mg/100 g body wt i.p. on days 20, 27 and 34; 25 control rats received i.p. saline at the same time intervals. All rats had a right unilateral nephrectomy within the first four days. Groups of control and PAN rats were killed at 21, 37, 52, 72 and 91 days. Renal sections were studied by immunofluorescence to quantitate interstitial macrophages, T lymphocytes and fibroblasts, and to characterize the deposition of the extracellular matrix (ECM) proteins (collagens I, III and IV, fibronectin and laminin) and the tissue inhibitor of the metalloproteinases (TIMP). Steady state concentrations of mRNA from the whole kidney for these ECM proteins, the metalloproteinases, TIMP, and transforming growth factor beta (TGF-beta 1) were quantitated by Northern blot analysis. Significant increases in the number of interstitial macrophages and T lymphocytes were found in the PAN rat groups compared to that in controls. All ECM proteins examined were quantitatively increased in the tubulo-interstitium of PAN rats. The pattern of distribution of some ECM proteins was also modified in experimental animals. TIMP was increased in the interstitium of PAN rats; at later times, TIMP was most prominent in sclerotic regions of the glomeruli and in tubular protein droplets. Northern blot analysis revealed increased steady-state mRNA levels for components of each of the ECM proteins, no change for the metalloproteinases--stromelysin or collagenase--and a marked increase for TIMP and TGF-beta 1 in PAN animals. The results of this study suggest that the diffuse interstitial fibrosis found in chronic PAN nephrosis results from both increased production of ECM proteins and decreased matrix degradation.

Three-dimensional morphometric analysis of segmental glomerulosclerosis in the rat

In idiopathic nephrotic syndrome, and in experimental models of nephrosis, changes of visceral epithelial cells involve the entire glomerular population while segmental sclerotic changes are reported to affect only a certain number of glomeruli. Because conventional determination of the percentage of glomeruli affected by sclerotic lesions is usually based on the examination of randomly selected sections, we wondered whether glomeruli appearing normal in a given section could be affected by sclerosis in other regions of the capillary tuft (CT). To assess the real incidence and the spatial extension of sclerotic changes at the level of single glomerulus, we used serial-section morphological analysis to measure the volume of the glomerulus and that of sclerosis lesions. In glomeruli from control rats and in glomeruli from adriamycin (ADR) treated rats surface area of Bowman's capsule (BC), CT and sclerotic regions were measured using stereology techniques in all the consecutive sections containing each individual glomerulus, and corresponding volumes were then calculated. Mean volume of BC and CT were not significantly different between control and ADR rats (0.71 +/- 0.03 and 0.53 +/- 0.03 vs. 0.76 +/- 0.04 and 0.53 +/- 0.02 microns 3 x 10(-6), respectively). The distribution of glomerular volume parameters in the ADR rats were more spread out than in control animals, indicating that some glomeruli became smaller while other became larger. No sclerotic changes were found in control rats, while in the three ADR rats 94, 90 and 92% of glomeruli, respectively, were affected by sclerotic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered distribution of excitatory amino acid receptors in temporal lobe epilepsy

In temporal lobe epilepsy, excitatory amino acid receptors in the hippocampus and temporal lobe may contribute to both increased excitability and vulnerability to excitotoxic damage. We used receptor autoradiography to examine the density of N-methyl- d-aspartate (NMDA) and kainic acid (KA) receptors in the hippocampus and parahippocampal gyrus obtained from five patients who had undergone anterior temporal lobectomy for the treatment of intractable seizures and from six control individuals, in which the hippocampus was obtained postmortem. Within the hippocampal formation, loss of [ 3H]KA and NMDA-sensitive l-[ 3H]glutamate binding was apparent in the sclerotic regions CA3, hilus, and CA1. In the subiculum and molecular layer of the denate gyrus, binding densities were maintained or even increased in some of the epileptic patients. A two-fold increase in l-[ 3H]glutamate binding, along with an increase in [ 3H]KA binding, was observed in the parahippocampal gyrus obtained from the epileptic patients. The results suggest that the vulnerability of the hippocampus in temporal lobe epilepsy may result, at least in part, from the presence of aberrant excitatory circuits in the parahippocampal gyrus.

Excitotoxic Amino Acid Receptors in Human Complex Partial Epilepsy

It has long been recognized that mesial temporal sclerosis is the most common pathologic finding in temporal lobes removed for the treatment of medically refractory complex partial epilepsy. The regions of the hippocampus most vulnerable contain the highest densities of excitatory amino acid receptors in the brain. We used receptor autoradiography to determine the density of N-methyl-D-aspartate (NMDA) and kainic acid (KA) receptors from 5 patients undergoing such surgery and compared the findings with 6 specimens obtained at postmortem. A 2-fold increase in the density of NMDA receptors and an increased density of KA receptors was found in entorhinal cortex in epileptic specimens. Loss of NMDA and KA receptor density was apparent in the sclerotic regions CA3 and CA1, but not in other areas of the hippocampus or dentate gyrus. These findings suggest that damage in the hippocampus may result, at least in part, from the presence of aberrant excitatory circuits in the entorhinal cortex.

FOUR CASES OF TYMPANOSCLEROSIS

Four cases of tympanosclerosis were reported with ahistorical review of its literatures. Two male and two female patients of less than 30 years old with chief complaints of otorrhoea and hearing loss were examined. Surgery revealed main sclerotic regions in the epitympanum and mastoid cavity. Several types of tympanoplasty were performed on these cases. Some clinical considerations on incidence, age and sex, clinical signs, audiogram, operation proce. (lures and histopathological findings of tympanos). clerosis were discussed.

Effects of x-radiation on growing bone. A preliminary report.

The deleterious effect of x-irradiation on growing bone has been recognized clinically for many years. In seeking more specific information, investigators have made use of bone-seeking radioactive isotopes, and recently small-field external irradiation of rats has been used (1). Our work has been with young dogs and involves precise irradiation of relatively small areas-as little as a few square millimeters in cross section. The method whereby we maintain exact localization and the dosimetry involved is discussed in another paper (2). Here we shall present some of the results achieved. Experimental Data The radiation used was 200–220 kvcp. An air dose of approximately 2,000 r was delivered in about forty minutes. This level of irradiation was selected on the basis of reports which indicated that it was likely to cause severe growth retardation (1, 3). All radiation in this series was directed toward the distal radial epiphyseal line from one side only. Dogs selected as examples were litter mates except for that shown in Figure 1. Pertinent information is presented in Table I. “Effective field size” indicates only that portion which includes the epiphyseal line. “Epiphyseal line length” designates a straight line measurement without an attempt to allow for curvature. The “twenty-day growth” measurement is taken from the time of irradiation and permits comparison between animals. Radiation Effects The earliest radiation effect visualized on the roentgenogram is usually an increase in density at the distal metaphyseal area. A typical, well established change can be seen on Figure 1 at the fifth day. The density resembles that of heavy metal poisoning except that it is sharply limited to the irradiation zone. The initial density appears faintly in twenty-four to forty-eight hours. We first thought that smaller areas took a day or two longer to respond. It seems more likely that the smaller zones are simply more difficult to see. The sclerotic region is the harbinger of complete growth arrest, in which the affected area is left behind as the viable portions continue their progress. Growth arrest usually follows the density in another twenty-four to forty-eight hours. It may, however, be delayed, as in the dog shown in Figure 2, where arrest did not occur until the seventh day. We have no explanation at present for the additional lapse. After growth ceases, the dense zone becomes less prominent, but it remains for a considerable time at the bottom of the defect. Small defects (Figs. 3 and 4) result in deep wells which, when viewed in a time-lapse motion picture study, give the illusion of a jigsaw cutting through bone. The advancing bone tends to bow slightly toward the defect but in general has remarkably straight walls. Eventually the “wells” become lost to view, probably due to remodeling of the metaphysis and tubular (circumferential) growth.