[Gyrate atrophy of choroid and retina, and hyperornithinemia].

Gyrate atrophy of the choroid and retina is a rare degenerative disease, characterized biochemically by a marked increase in blood ornithine levels, due to deficiency of ornithine S-amino transferase. 4 men aged 35, 36, 48 and 62 years are described with different stages of myopia, night blindness and loss of peripheral vision, which progressed to tunnel vision and partial blindness. Onset of the disease was at ages 3, 10 and 15 years, respectively, while in the 4th patient there was delayed expression starting at about age 50. Most had posterior subcapsular cataracts, and the ocular fundus exhibited demarcated circular areas of chorioretinal degeneration. So far the only patients described in Israel have been of Iraqui origin. Our fourth patient originated from Istanbul, and he may represent a hitherto undescribed variant with a much delayed expression of the disease.

Plasminogen activator inhibitor-1 mRNA is localized in the ciliary epithelium of the rodent eye.

PURPOSE: To identify in the adult and developing rodent eye cells expressing the gene encoding plasminogen activator inhibitor-1 (PAI-1), an important component of the fibrinolytic system. METHODS: PAI-1 mRNA was localized in cryostat thin eye sections via in situ hybridization analysis using specific 35S-labeled riboprobes. PAI-1 activity was tested in the aqueous humor using one-phase reverse zymography. RESULTS: In the adult eye, PAI-1 mRNA was detected exclusively in epithelial cells of the ciliary processes, primarily in the apexes. In addition, PAI-1 activity was detected in the aqueous humor. PAI-1 mRNA was first found in the ciliary epithelium in embryonic day 18.5, when the ciliary body has reached an advanced developmental stage. PAI-1 mRNA was also detected in the ganglion cell layer of the retina at postnatal days 1 to 4, when angiogenesis takes place. CONCLUSIONS: During development, PAI-1 is likely to be involved in retina vascularization, in agreement with other cases of angiogenesis. Results for the adult eye indicate that the ciliary epithelium is the source for PAI-1 activity found in the aqueous humor. The results suggest that PAI-1 plays a role in balancing fibrinolysis and proteolysis specifically in the anterior segment of the eye, implying that PAI-1 overproduction in the ciliary epithelium could shift the balance against proteolysis and thus may interfere with aqueous outflow.

[D-lactic acidosis in short bowel syndrome].

A boy of 20 months and a girl of 27 months who had previously undergone massive bowel resection due to congenital intestinal obstruction are described. During gradual reduction of total parenteral nutrition and initiation of oral feeding, both developed severe, acute metabolic acidosis, accompanied by encephalopathy and ataxia. After the laboratory identification of massive amounts of the d-isomer of lactic acid in urine and blood, both were successfully treated with i.v. bicarbonate, and metronidazole to suppress the overgrowth of colonic lactobacilli responsible for the metabolic crisis.

AlphaMUPA mice: a transgenic model for increased life span.

AlphaMUPA is a line of transgenic mice that, compared with their wild type (WT) counterparts, spontaneously eat less (approximately 20%) and live longer (average approximately 20%), thus resembling dietary-restricted (DR) mice. Here, we show that body temperature was significantly reduced in alphaMUPA compared with WT throughout a wide range of ages. Plasma corticosterone was significantly higher in young alphaMUPA compared to young WT; however, it significantly declined in aged alphaMUPA, but not in aged WT. In addition, age-associated thymus involution occurred in alphaMUPA as it did in WT. Thus alphaMUPA mice appear to largely resemble, but also to somewhat differ from diet-restricted animals. We also report on four new transgenic lines that, like alphaMUPA, produced in the brain the mRNA that encodes the extracellular protease urokinase (uPA); however, transgenic uPA expression was most extensive and widespread in the alphaMUPA brain, where it also occurred in the hypothalamus. AlphaMUPA was also the only line that ate less, but also showed another characteristic, high frequency leg muscle tremor seen only at unstable body states. We hypothesize that transgenic uPA in the brain could have caused the alphaMUPA phenotypic alterations. Thus alphaMUPA offers a unique transgenic model of inherently reduced eating to investigate the homeostatic state of delayed aging at the systemic and single-cell levels.

mRNAs encoding urokinase-type plasminogen activator and plasminogen activator inhibitor-1 are elevated in the mouse brain following kainate-mediated excitation.

Urokinase-type plasminogen activator (uPA) is an inducible extracellular serine protease implicated in fibrinolysis and in tissue remodeling. Recently, we have localized uPA mRNA strictly in limbic structures and the parietal cortex of the adult mouse brain. Here, we tested whether the systemic treatment of mice with kainic acid (KA), an amino acid inducing limbic seizures, could elevate in the brain mRNAs encoding uPA and its specific inhibitor, plasminogen activator inhibitor-1 (PAI-1), a major antifibrinolytic agent. Brain sections encompassing the hippocampus were tested through in situ hybridization using radiolabeled riboprobes specific for the two mRNA species. The results showed that KA greatly enhanced both mRNA species in sites of limbic structures and cortex. However, in the hypothalamus and brain blood vessels only PAI-1 mRNA was elevated. Those were also the only two locations where PAI-1 mRNA was detected in the non-treated control brain, although at a low level. For both mRNAs, KA enhancement was first evident 2-4 h after treatment, and it was most prolonged in the hippocampal area, where prominent hybridization signals persisted for three days. Here, both mRNAs were initially elevated in the hilar region of the dentate gyrus and in the molecular and oriens layers; however, PAI-1 mRNA became evident throughout the area, while uPA mRNA became especially pronounced in the CA3/CA4 subfield. In the cortex both mRNA types were induced, but only uPA mRNA was elevated in the retrosplenial cortex, and also in the subiculum. In the amygdaloid complex, uPA mRNA was restricted to the basolateral nucleus, whereas PAI-1 mRNA was seen throughout the structure, however, excluding this nucleus. These data show that seizure activity enhances the expression of uPA and PAI-1 genes in the brain; the patterns of enhancement suggest that the protease and its inhibitor may act in brain plasticity in synchrony, however, also independently of each other. Furthermore, the results suggest that by elevating PAI-1 mRNA in brain blood vessels, limbic seizures generate a risk for stroke.

Transgenic mice overexpressing urokinase-type plasminogen activator in the brain exhibit reduced food consumption, body weight and size, and increased longevity.

Transgenic mice designated alpha MUPA overproduce in many brain sites the urokinase-type plasminogen activator (uPA), a protease implicated in fibrinolysis and extracellular proteolysis. Here we report that, compared to their parental wild-type control, alpha MUPA mice spontaneously consumed less food (approximately 20%), exhibited reduced body weight (approximately 20%) and length (approximately 6%), and also prolonged life span (approximately 20%). The alpha MUPA phenotype is thus reminiscent of experimental animals in which dietary restriction enhances longevity. Reduced eating and body weight were observed in alpha MUPA mice shortly after weaning, and these levels were maintained virtually throughout their lifetime. alpha MUPA mice also exhibited lower levels of blood sugar (approximately 9%), smaller litter size (approximately 14%), and lower birth frequency (approximately 10%). In the adult alpha MUPA brain, uPA mRNA has been localized through in situ hybridization also in neuronal cells of the hypothalamic paraventricular nucleus, a region implicated in feeding behavior. No signals of uPA mRNA could be detected in the paraventricular nucleus of control mice. It is suggested that in alpha MUPA mice, overproduction of uPA in brain sites controlling feeding leads to reduced food consumption that, in turn, results in retardation of growth and body weight and also in increased longevity. The alpha MUPA experimental model may have implications for normal mice.

Localization of urokinase-type plasminogen activator mRNA in the adult mouse brain.

Urokinase-type plasminogen activator (uPA) is an inducible serine protease, secreted by a variety of cell types, that functions in fibrinolysis and has been implicated also in events such as cell migration and tissue remodeling and repair. To explore the role of uPA in the adult brain we have now screened the whole mouse brain for cells expressing the uPA gene through in situ hybridization using 35S-complementary RNA. uPA mRNA was visualized predominantly in three regions: (1) the subicular complex, (2) the entorhinal cortex, (3) the parietal cortex, where the signal was somewhat lower and confined to layers IV and VI. Weaker signals were seen in the basolateral nucleus of the amygdala and in the anterodorsal thalamic nucleus, and also in the hilus of the dentate gyrus where labeling was slightly over background. Cells exhibiting uPA mRNA signaling were large neurons according to morphological criteria. These results support the view of uPA being involved in neuronal functions of the adult brain, specifically in the hippocampal formation and the parietal cortex.

Overexpression of urokinase-type plasminogen activator in transgenic mice is correlated with impaired learning.

Transgenic mice designated alpha MUPA overproduce in the brain murine urokinase-type plasminogen activator (uPA), an extracellular protease implicated in tissue remodeling. We have now localized, by in situ hybridization, extensive signal of uPA mRNA in the alpha MUPA cortex, hippocampus, and amygdala, sites that were not labeled in counterpart wild-type mice. Furthermore, biochemical measurements reveal a remarkably high level of enzymatic activity of uPA in the cortex and hippocampus of alpha MUPA compared with wild-type mice. We have used the alpha MUPA mice to examine whether the abnormal level of uPA in the cortex and the limbic system affects learning ability. We report that alpha MUPA mice perform poorly in tasks of spatial, olfactory, and taste-aversion learning, while displaying normal sensory and motor capabilities. Our results suggest that uPA is involved in neural processes subserving a variety of learning types.