Lipoxygenase-mediated generation of lipid peroxides enhances ferroptosis induced by erastin and RSL3

In cancer cells the small compounds erastin and RSL3 promote a novel type of cell death called ferroptosis, which requires iron-dependent accumulation of lipid reactive oxygen species. Here we assessed the contribution of lipid peroxidation activity of lipoxygenases (LOX) to ferroptosis in oncogenic Ras-expressing cancer cells. Several 12/15-LOX inhibitors prevented cell death induced by erastin and RSL3. Furthermore, siRNA-mediated silencing of ALOX15 significantly decreased both erastin-induced and RSL3-induced ferroptotic cell death, whereas exogenous overexpression of ALOX15 enhanced the effect of these compounds. Immunofluorescence analyses revealed that the ALOX15 protein consistently localizes to cell membrane during the course of ferroptosis. Importantly, treatments of cells with ALOX15-activating compounds accelerated cell death at low, but not high doses of erastin and RSL3. These observations suggest that tumor ferroptosis is promoted by LOX-catalyzed lipid hydroperoxide generation in cellular membranes.

Temporal and spatial dynamics of the periodic increase in intracellular free calcium at fertilization of golden hamster eggs

A series of periodic increases in intracellular free calcium concentration ([Ca2+]i) occurred upon fertilization in golden hamster eggs. The spatial distribution of the Ca2+ transients was investigated in single zona-free, aequorin-injected eggs, inseminated by single sperm. A supersensitive TV camera system for recording Ca2+-aequorin luminescence enabled us to observe the spatial distribution of the Ca2+ rise. In the first response, which usually occurred 10-30 sec after the sperm attachment, the increase in [Ca2+]i began near the sperm attachment site, and the Ca2+ rise spread over the entire egg within 4-7 sec. The Ca2+ rise attained its peak in 5-8 sec, declined with almost even distribution, and ceased in 12-17 sec. The spreading Ca2+ rise was repeated in the second and sometimes the third response, starting from the same focus, but spreading more rapidly (approximately 2 sec). In succeeding responses [Ca2+]i increased synchronously in the whole cytoplasm within 1 sec. When additional sperm attached to the egg after the occurrence of the first response by the first sperm, the spread of the Ca2+ rise could take place from near the site of additional sperm attachment but only in the second or third response.

Growth hormone and prolactin release after injection of thyrotropin-releasing hormone in patients with depression

The effects of thyrotropin-releasing hormone (TRH) on the release of growth hormone (GH), prolactin (PRL) and thyrotropin (TSH) were investigated in patients with depression. Intravenous injection of synthetic TRH (500 mug) caused a significant increase in plasma GH (peak value: 7.7 minus 35.0 ng/ml) in 8 of 13 patients with mental depression. After clinical recovery these patients had no response of plasma GH to TRH. TRH administration did not raise plasma GH in normal subjects examined. Plasma PRL responses to TRH were significantly enchanced (P smaller than 0.05) in depressed patients compared with control subjects. Plasma TSH responses to TRH were significantly blunted in patients with depression (P smaller than 0.05). These results suggest disorders in the hypothalamo-pituitary function in depression.

Calcium transport in perfused duodena from normal chicks: enhancement within fourteen minutes of exposure to 1,25-dihydroxyvitamin D3

The effect of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3) on calcium transport was studied in vascularly perfused duodena of normal, vitamin D-replete chicks. Addition of 130 pM 1,25(OH)2D3 to the perfusate resulted in a significant increase in 45Ca transport from the lumen to the vascular effluent within 14 min; the transport rate rose to 140% of levels in comparable preparations exposed for 40 min to vehicle. No effects of 1,25(OH)2D3 were noted on the back flux or transfer of 45Ca from the vascular effluent to the lumen. Vascular perfusion with 100 microM colchicine, an antimicrotubular agent, abolished the rapid lumen-to-vascular effluent effect of 1,25(OH)2D3 on 45Ca transport, relative to preparations exposed to the secosteroid and 100 microM lumicolchicine, (a light inactivated analog of colchicine). Colchicine did not, however, alter basal 45Ca transport rates. Addition of 130 pM 1,25(OH)2D3 to the lumenal compartment of normal chicks or vascular perfusion of duodena from vitamin D-deficient birds failed to increase 45Ca transport above control levels. Perfusion of duodena from normal chicks with 650 pM 1,25(OH)2D3 further increased calcium transport to 170% of levels observed in preparations treated with 130 pM steroid, and 210% of levels in controls. Although 15 nM vitamin D3 had no effect, in one series of experiments 125 nM 25-hydroxyvitamin D3 elicited vascular calcium levels that were 185% of controls at 40 min. These results suggest that 1,25(OH)2D3 can act in vitamin D-replete animals to produce rapid unidirectional calcium transport responses (through unknown mechanisms), as well as by interaction with intestinal nuclear receptors in D-deficient animals to promote induction of protein(s) that support long acting calcium transport responses.

Acute systemic inflammatory response syndrome in subarachnoid hemorrhage

BACKGROUND AND PURPOSE

Systemic inflammatory response syndrome (SIRS) without infection is a well-known phenomenon that accompanies various acute cerebral insults. We sought to determine whether the initial SIRS score was associated with outcome in subarachnoid hemorrhage (SAH).

METHODS

In 103 consecutive patients with SAH, the occurrence of SIRS was assessed according to the presence of >/=2 of the following: temperature of <36 degrees C or >38 degrees C, heart rate of >90 bpm, respiratory rate of >20 breaths/min, and white blood cell count of <4000/mm(3) or >12 000/mm(3). SIRS criteria and other prognostic parameters were evaluated as predictors of dichotomous Glasgow Outcome Scale score.

RESULTS

SIRS was highly related to poor clinical grade (Hunt and Hess clinical grading scale), a large amount of SAH on CT (Fisher CT group), and high plasma glucose concentration on admission. By univariate analysis, the occurrence of SIRS was associated with higher mortality and morbidity rates than was the nonoccurrence (P<0.001). Among individual SIRS criteria, heart rate (P=0.003), respiration rate (P=0.003), and white blood cell count (P=0.03) were significant outcome predictors. By multivariate logistic regression analysis, the presence of SIRS independently predicted outcome. SIRS carried an increased risk of subsequent intracranial complications such as vasospasm and normal pressure hydrocephalus, as well as systemic complications.

CONCLUSIONS

In SAH patients, SIRS on admission reflected the extent of tissue damage at onset and predicted further tissue disruption, producing clinical worsening and, ultimately, a poor outcome.

Unruptured intracranial vertebral artery dissection. Clinical course and serial radiographic imagings

BACKGROUND AND PURPOSE

Intracranial vertebral artery dissection is an increasingly recognized cause of stroke. However, little is known about its natural history and clinical manifestations, and appropriate management protocol has not yet been established. This study was performed to clarify its clinical course and determine the best management protocol.

METHODS

This study is a retrospective clinical and radiographic review of 11 patients with 13 lesions who presented between 1990 and 1996. Patients with a history of trauma and those who presented with subarachnoid hemorrhage were excluded. The 11 patients comprised seven men and four women, who ranged in age from 34 to 71 years, with a mean age of 47 years. Ten patients presented with ischemic symptoms.

RESULTS

Although recurrent ischemic attacks were observed in two patients, most (90%) subsequently made a good recovery and returned to their previous lifestyle. Five arteries showed the typical "string sign" or "pearl and string sign" on initial angiography. They changed in the follow-up examinations, which demonstrated either resolution of the stenosis or progression to complete occlusion. In contrast, the angiographic signs of complete occlusion (three arteries) or aneurysmal dilatation without luminal stenosis (four arteries) remained unchanged during the observation period of 5 months to 2.5 years. MRI was a sensitive tool for diagnosing intracranial vertebral artery dissection; intramural thrombus and intimal flap were the two major findings. MR angiography was also useful for demonstrating abnormalities of the arterial signal column such as pseudolumen or aneurysmal dilatation.

CONCLUSIONS

The natural history of unruptured intracranial vertebral artery dissection seems relatively benign, with a high probability (62%) of spontaneous angiographic cure. Some persistent aneurysmal dilatation may be amenable to intravascular coil embolization.

Systematic review of the natural history of vestibular schwannoma

OBJECT

Magnetic resonance (MR) imaging now permits diagnosis of increasing numbers of small, minimally symptomatic vestibular schwannomas (VSs). Because VS growth patterns over time are very important in refining treatment strategies, these matters were systematically reviewed.

METHODS

An extensive MEDLINE search was performed to cull studies on VS growth according to sequential imaging. The percentages of growing and regressing tumors and lesions requiring treatment during follow-up periods were calculated. Factors associated with differences among studies were identified. Twenty-six studies including 1340 patients met all inclusion criteria. The overall frequency of VS growth during a mean follow-up period of 38 months was 46% (95% confidence interval [CI] 43-48%) and that of regression was 8% (95% CI 6-10%). The mean annual tumor growth rate was 1.2 mm/year. Furthermore, the percentage of cases requiring treatment during follow up was 18% (95% CI 16-21%). According to results of a sensitivity analysis, evaluation by serial MR imaging (39%, 95% CI 35-43%) and a prospective study design (29%, 95% CI 21-37%) were associated with less frequent reported tumor growth.

CONCLUSIONS

Although their applicability may be limited to relatively elderly patients with small tumors, data revealing a limited frequency of VS enlargement and an infrequent necessity for eventual therapy should assist decision-making in the treatment of small VSs causing minimal symptoms.

Free calcium wave upon activation in Xenopus eggs

Eggs of Xenopus laevis were preloaded with aequorin and the spatial and temporal pattern of free calcium release in the egg cortex on artificial activation was determined by the aequorin luminescence emitted from the thin cortical layer of naturally opaque eggs. The aequorin luminescence was detected with a photonic microscope system consisting of a light microscope and a two-dimensional photon-counting system with an image processor. A free calcium increase was initiated around the point of prick activation. The state of increased Ca2+ propagated in the cortical cytoplasm of the egg as a wave with a velocity of about 8 micron/sec at 22 degrees C. This wave reached the antipode by 5 to 6 min of prick activation. The spatial pattern of the Ca2+ wave was similar to that of changes in brightness of the egg surface on activation, termed the "activation wave" by K. Hara and P. Tydeman (1979, Wilhelm Roux's Arch. Dev. Biol. 186, 91-94). To examine the temporal correlation between the Ca2+ wave and the activation wave, images of aequorin luminescence and those of the egg cortex taken by incident light illumination were recorded alternately in the same egg. The zone of free calcium increase corresponded to the light (relaxation) zone of the activation wave, where exocytosis of cortical granules and elongation of microvilli were taking place.

Bone changes and carotid atherosclerosis in postmenopausal women

BACKGROUND AND PURPOSE

Because of increased life expectancy, most postmenopausal women today suffer from osteoporosis and atherosclerotic diseases, which are currently considered unrelated diseases. Our study was aimed at analyzing relations between bone mineral density (BMD) and ultrasonographic assessment of carotid wall characteristics.

METHODS

The relation of carotid atherosclerosis to BMD was examined in 30 postmenopausal women aged 67 to 85 years. High-resolution B-mode ultrasonography was performed, and the severity of carotid atherosclerosis was determined by plaque score. BMD was measured by dual-energy x-ray absorptiometry.

RESULTS

The correlation of plaque score with low total BMD was r = .549 (P < .002). Multiple linear regression analysis indicated significant correlation of plaque score with total cholesterol level and low total BMD.

CONCLUSIONS

Our results suggest a relation between carotid atherosclerosis, one of the major causes of ischemic cerebrovascular diseases, and osteoporosis.

Astrocytes retrovirally transduced with BDNF elicit behavioral improvement in a rat model of Parkinson's disease

Neurotrophic factors that improve the survival of specific neuronal types during development and after exposure to various neuronal insults hold potential for treatment of neurodegenerative diseases. In particular, brain-derived neurotrophic factor (BDNF) has been shown to exert trophic and protective effects on dopaminergic neurons, the cell type known to degenerate in Parkinson's disease. To determine whether increased levels of biologically produced BDNF affect the function or regeneration of damaged dopaminergic neurons, the effects of grafting astrocytes transduced with the human BDNF gene into the striatum of the partially lesioned hemiparkinsonian rat were examined. Replication deficient retroviruses carrying either human prepro-BDNF or human alkaline phosphatase (AP) cDNA were used to transduce primary type 1 astrocytes purified from neonatal rat cortex. In vitro, BDNF mRNA was expressed by BDNF transduced astrocytes (BDNF astrocytes), but not control AP transduced astrocytes (AP astrocytes), as determined by reverse transcription polymerase chain reaction (RT-PCR). The modified astrocytes were injected into the right striatum 15 days after partial lesioning of the right substantia nigra with 6-hydroxydopamine. Transplantation of BDNF astrocytes, but not AP astrocytes, significantly attenuated amphetamine-induced rotation by 45% 32 days after grafting. Apomorphine-induced rotation increased over time in both groups, but was not significantly different in the BDNF-treated group. The modified BDNF astrocytes survived well with non-invasive growth in the brain for up to 42 days. Although BDNF mRNA positive cells were not detected within the graft site using in situ hybridization, alkaline phosphatase immunoreactive (IR) cells were present in control graft sites suggesting that the retroviral construct continued to be expressed at 42 days. Analysis of the density of tyrosine hydroxylase (TH)-IR fibers showed no effect of BDNF on TH-IR fiber density in the striatum on the lesioned side. These findings suggest that ex vivo gene therapy with BDNF ameliorates parkinsonian symptoms through a mechanism(s) other than one involving an effect of BDNF on regeneration or sprouting from dopaminergic neurons.

Constitutive reactive oxygen species generation from autophagosome/lysosome in neuronal oxidative toxicity

Reactive oxygen species (ROS) are involved in several cell death processes, including cerebral ischemic injury. We found that glutamate-induced ROS accumulation and the associated cell death in mouse hippocampal cell lines were delayed by pharmacological inhibition of autophagy or lysosomal activity. Glutamate, however, did not stimulate autophagy, which was assessed by a protein marker, LC3, and neither changes in organization of mitochondria nor lysosomal membrane permeabilization were observed. Fluorescent analyses by a redox probe PF-H(2)TMRos revealed that autophagosomes and/or lysosomes are the major sites for basal ROS generation in addition to mitochondria. Treatments with inhibitors for autophagy and lysosomes decreased their basal ROS production and caused a burst of mitochondrial ROS to be delayed. On the other hand, attenuation of mitochondrial activity by serum depletion or by high cell density culture resulted in the loss of both constitutive ROS production and an ROS burst in mitochondria. Thus, constitutive ROS production within mitochondria and lysosomes enables cells to be susceptible to glutamate-induced oxidative cytotoxicity. Likewise, inhibitors for autophagy and lysosomes reduced neural cell death in an ischemia model in rats. We suggest that cell injury during periods of ischemia is regulated by ROS-generating activity in autophagosomes and/or lysosomes as well as in mitochondria.

Restoration of normal pituitary gonadotropin reserve by administration of luteinizing-hormone-releasing hormone in patients with hypogonadotropic hypogonadism

To elucidate whether diminished pituitary gonadotropin reserve can be restored by repeated stimulation with luteinizing-hormone-releasing hormone, plasma luteinizing hormone and follicly-stimulating hormone responses were studied before and after daily intravenous infusion of 400 mug of luteinizing-hormone-releasing hormone for two to 23 days, in patients with hypogonadotropic hypogonadism of various causes. In five of nine patients with isolated gonadotropin deficiency, the impaired plasma luteinizing hormone response was restored to normal after treatment for seven days or more, whereas it was unchanged in four patients treated for less than five days. However, six patients with anorexia nervosa regained normal responses after three to five days' treatment. Five of nine patients with organic hypothalamopituitary lesions also showed normal responsiveness after five to seven days' treatment. These results suggest that the response to the test after repeated administration of luteinizing-hormone-releasing hormone is of value for the diagnosis of hypogonadism of hypothalamic origin.

A pooled analysis of case-control studies of thyroid cancer. II. Menstrual and reproductive factors

OBJECTIVE

It has been suggested that female hormones, and hence menstrual and reproductive factors, play a role in thyroid cancer etiology. Epidemiological data, however, are limited and inconsistent, partly because of the small number of cases included in each study. To clarify the etiology of thyroid cancer, we conducted a pooled analysis of original data from 14 case-control studies, 4 from the United States, 2 from Asia, and 8 from Europe.

METHODS

This analysis included a total of 2,247 female cases of thyroid cancer (80% papillary) and 3,699 control women. Pooled odds ratios (OR) were estimated using logistic regression, conditioning on study and (i) matching sets for individually matched studies, or (ii) quinquennia of age for the other studies. Additional terms for age and history of radiation exposure were included in the regression equations.

RESULTS

The OR per year of later menarche was 1.04 (95% confidence interval (CI) 1.0-1.1). Compared to premenopausal women, the OR was 1.3 for women with natural menopause, and 1.8 for those with artificial menopause, but the studies were heterogeneous and the association may be due, at least in part, to diagnostic or ascertainment bias. Parity, spontaneous or induced abortions and history of infertility were not associated with thyroid cancer risk. The OR was above unity in women reporting later age at first birth (OR = 1.1, 95% CI 1.0-1.3 for 5-year delay) and higher in the first years after a birth.

CONCLUSIONS

The associations of menstrual and reproductive factors with thyroid cancer risk were generally weak, but appeared stronger among women diagnosed with thyroid cancer at younger ages.

Human chorionic gonadotropin-like substance in nonendocrine tissues of normal subjects

By means of two assay systems, a beta chain human chorionic gonadotropin radioimmunoassay and a radioreceptor gonadotropin assay, a chorionic gonadotropin-like substance was demonstrated in extracts of liver and colon obtained at autopsy from three patients who died of nonneoplastic disease. In contrast to placental chorionic gonadotropin, colon and liver chorionic gonadotropin was not bound to concanavalin A-Sepharose columns, indicating that this substance possessed little or no carbohydrate. Previous workers demonstrated that desialylated human chorionic gonadotropin possesses little or no bioactivity in vivo but retains full radioreceptor and radioimmunoassay activity in vitro. Our data suggest that the genome responsible for the human chorionic gonadotropin production is not completely suppressed in adult nonendocrine tissues, and that the chorionic gonadotropin produced by colon and liver has little or no bioactivity in vivo because of its low carbohydrate content. Since many normal tissues produce chorionic gonadotropin, bioactivity may be modulated by regulation of carbohydrate content.

Critical role of ABCA1 transporter in sphingosine 1-phosphate release from astrocytes

Sphingosine 1-phosphate (S1P) is accumulated in lipoproteins, especially high-density lipoprotein (HDL), in plasma. However, it remains uncharacterized how extracellular S1P is produced in the CNS. The treatment of rat astrocytes with retinoic acid and dibutyryl cAMP, which induce apolipoprotein E (apoE) synthesis and HDL-like lipoprotein formation, stimulated extracellular S1P accumulation in the presence of its precursor sphingosine. The released S1P was present together with apoE particles in the HDL fraction. S1P release from astrocytes was inhibited by the treatment of the cells with glybenclamide or small interfering RNAs specific to ATP-binding cassette transporter A1 (ABCA1). Astrocytes from Abca1-/- mice also showed impairment of retinoic acid/dibutyryl cAMP-induced S1P release in association with the blockage of HDL-like lipoprotein formation. However, the formation of either apoE or lipoprotein itself was not sufficient, and additional up-regulation of ABCA1 was requisite to stimulate S1P release. We conclude that the S1P release from astrocytes is coupled with lipoprotein formation through ABCA1.

Migrastatin, a new inhibitor of tumor cell migration from Streptomyces sp. MK929-43F1. Taxonomy, fermentation, isolation and biological activities

A new compound, migrastatin, was isolated from a cultured broth of Streptomyces sp. MK929-43F1, as an inhibitor of tumor cell migration. It was purified by column chromatographies on silica gel and Sephadex LH-20 and HPLC. Migrastatin has the molecular formula of C27H39NO7 consisting of 14-membered macrolide and glutarimide moiety. It inhibited spontaneous migration of human esophageal cancer EC17 cells. Migration inhibitory activity of migrastatin was not dependent on cytotoxicity or inhibition of protein synthesis.

Factors affecting peritumoral brain edema in meningioma: special histological subtypes with prominently extensive edema

Various degrees of peritumoral brain edema (PTBE) are observed in patients with intracranial meningiomas. Factors affecting the occurrence of PTBE in intracranial meningioma were investigated. PTBE was investigated retrospectively for 110 patients with primary intracranial meningiomas. Predictive factors related to PTBE were analyzed, for example patient age, sex, magnetic resonance imaging features (contrast enhancement, tumor shape, tumor location, tumor volume), angiographical features (tumor stain, pial-cortical arterial supply, venous obstruction), and histopathological features (histological subtypes, mindbomb homolog 1 labeling index (MIB1-LI)). Histological subtypes were classified into World Health Organization (WHO) grade I common type (meningothelial, transitional, fibrous), grade I uncommon type, and grade II and III types. The extent of PTBE was assessed by calculation of the edema index (EI). PTBE was present in 53 cases (48 %). Male sex, heterogeneous enhancement, superficial location, tumor volume (≥10 cm(3)), remarkable tumor stain, pial supply, venous obstruction, malignant pathology, and MIB1-LI ≥4 % were correlated with PTBE in univariate analysis. Pial supply and remarkable tumor stain were correlated with PTBE in multivariate analysis. WHO grade I uncommon type had obviously higher EI than WHO grade I common type, and WHO grade II and III types (P < 0.001). Seven cases with prominently high EI (EI ≥10) were all WHO grade I uncommon type, including angiomatous, microcystic, secretory, and lymphoplasmacyte-rich meningioma. Prominently extensive PTBE might indicate the presence of WHO grade I uncommon type meningioma.

Risk of cancer among children exposed in utero to A-bomb radiations, 1950-84

This study examines the risk of cancer (incidence) over 40 years among the in-utero exposed survivors of the atomic bombing of Hiroshima and Nagasaki, and adds eight years of follow-up to a previous report confined to mortality. Only two cases of childhood cancer were observed among these survivors in the first 14 years of life; both had been heavily exposed. Subsequent cancers have all been of the adult type. Not only did the observed cancers occur earlier in the 0.30 + Gy dose group than in the 0 Gy dose group but also the incidence continues to increase, and the crude cumulative incidence rate, 40 years after the A-bombing, is 3.9-fold greater in the 0.30 + Gy group. In the observation period 1950-84, based on the absorbed dose to the mother's uterus as estimated by the 1986 dosimetry system (DS86), the relative risk of cancer at 1 Gy is 3.77 with a 95% confidence interval of 1.14-13.48. For the entire 0.01 + Gy dose group the average excess risk per 10(4) person-year-gray is 6.57 (0.07-14.49) and the estimated attributable risk is 40.9% (2.9-90.2%). These results, when viewed in the perspective of fetus doses, suggest that susceptibility to radiation-induced cancers is higher in prenatally than in postnatally exposed survivors (at least those exposed as adults). However, definitive conclusions must await further follow-up studies.

Simultaneous oscillations of Ca2+ efflux and tension generation in the permealized plasmodial strand of Physarum

Calcium is now generally thought to play a key role in regulating a variety of cellular movements. When the plasmodium of Physarum polycephalum was treated with the calcium-ionophore A23187 or the quasi-ionophore amphotericin B, Ca2+ leaked out. Ca2+ efflux into the ambient solution from the plasmodial strand segment was measured by the luminescence of a photoprotein aequorin, and the tensile force production was recorded simultaneously. Ca2+ efflux oscillated with the same period as the cycle of tension generation in the strand, but the phase of cyclic changes in Ca2+ efflux was opposite to that of tension generation. That is, Ca2+ efflux fell in the increasing tension phase and rose in the decreasing tension phase. Cyclic changes in efflux of Ca2+ are provisionally interpreted as reflecting corresponding changes in concentrations of free Ca2+ in the cytoplasm.

Experimental model of lacunar infarction in the gyrencephalic brain of the miniature pig: neurological assessment and histological, immunohistochemical, and physiological evaluation of dynamic corticospinal tract deformation

BACKGROUND AND PURPOSE

Lacunar infarction accounts for 25% of ischemic strokes, but the pathological characteristics have not been investigated systematically. A new experimental model of lacunar infarction in the miniature pig was developed to investigate the pathophysiological changes in the corticospinal tract from the acute to chronic phases.

METHODS

Thirty-five miniature pigs underwent transcranial surgery for permanent anterior choroidal artery occlusion. Animals recovered for 24 hours (n=7), 2 (n=5), 3 (n=2), 4 (n=2), 6 (n=1), 7 (n=7), 8 (n=2), and 9 days (n=1), 2 weeks (n=2), 4 weeks (n=3), and more than 4 weeks (n=3). Neurology, electrophysiology, histology, and MRI were performed. Seven additional miniature pigs underwent transient anterior choroidal artery occlusion to study muscle motor-evoked potentials and evaluate corticospinal tract function during transient anterior choroidal artery occlusion.

RESULTS

The protocol had a 91.4% success rate in induction of internal capsule infarction 286+/-153 mm(3) (mean+/-SD). Motor-evoked potentials revealed the presence of penumbral tissue in the internal capsule after 6 to 15 minutes anterior choroidal artery occlusion. Total neurological deficit scores of 15.0 (95% CI, 13.5 to 16.4) and 3.4 (0.3 to 6.4) were recorded for permanent anterior choroidal artery occlusion and sham groups, respectively (P<0.001, maximum score 25) with motor deficit scores of 3.4 (95% CI, 2.9 to 4.0) and 0.0 (CI, 0.0 to 0.0), respectively (P<0.001, maximum score 9). Histology revealed that the internal capsule lesion expands gradually from acute to chronic phases.

CONCLUSIONS

This new model of lacunar infarction induces a reproducible infarct in subcortical white matter with a measurable functional deficit and evidence of penumbral tissue acutely.

Somatostatin induces hyperpolarization in pancreatic islet alpha cells by activating a G protein-gated K+ channel

Somatostatin inhibits glucagon-secretion from pancreatic alpha cells but its underlying mechanism is unknown. In mouse alpha cells, we found that somatostatin induced prominent hyperpolarization by activating a K+ channel, which was unaffected by tolbutamide but prevented by pre-treating the cells with pertussis toxin. The K+ channel was activated by intracellular GTP (with somatostatin), GTPgammaS or Gbetagamma subunits. It was thus identified as a G protein-gated K+ (K(G)) channel. RT-PCR and immunohistochemical analyses suggested the K(G) channel to be composed of Kir3.2c and Kir3.4. This study identified a novel ionic mechanism involved in somatostatin-inhibition of glucagon-secretion from pancreatic alpha cells.

Lower brainstem afferents to the cat posterior hypothalamus: a double-labeling study

Using a double-immunostaining technique with cholera toxin (CT) as a retrograde tracer, the authors examined the cells of origin and the histochemical nature of lower brainstem afferents to the cat posterior hypothalamus. The posterior hypothalamus, in particular the lateral hypothalamic area, receives substantial afferent projections from: substantia nigra, peripeduncular nucleus, ventral tegmental area, periaqueductal grey, mesencephalic reticular formation, peribrachial region including the locus coeruleus complex, rostral raphe nuclei and the rostral part of the nucleus magnus. In addition, a moderate number of retrogradely labeled neurons was found in: Edinger-Westphal nucleus, nucleus reticularis pontis oralis, nucleus reticularis magnocellularis, caudal lateral bulbar reticular formation around the nucleus ambiguus and lateral reticular nucleus and the nucleus of the solitary tract. The posterior hypothalamus receives: 1) dopaminergic inputs from A8, A9 and A10 cell groups; 2) noradrenergic inputs from A6 and A7 pontine, as well as A1 and A2 bulbar cell groups; 3) adrenergic inputs from C1 cell group in the caudal medulla; 4) serotoninergic inputs from the rostral raphe nuclei (B6, B7 and B8 cell groups); 5) cholinergic inputs from the peribrachial region of the dorsal pontine tegmentum as well as from the nucleus reticularis magnocellularis of the medulla; 6) peptidergic inputs such as methionine-enkephalin, substance P, corticotropin-releasing factor and galanin that originate mainly in the mesencephalic periaqueductal grey, the dorsal raphe nucleus and the peribrachial region of the dorsal pontine tegmentum.

High-performance capillary electrophoresis/frontal analysis for the study of protein binding of a basic drug

A simple high-performance capillary electrophoresis (HPCE) method based on the principle of frontal analysis was applied to the determination of the concentration of unbound basic drug in protein binding equilibrium. A small volume of sample solution (approximately 80 nL) containing 113-340 microM of verapamil (VER) and 100-550 microM of human serum albumin was introduced into the fused silica capillary (effective length, 22 cm; 50-microns i.d.) by suction. Because the silanol groups on the inner surface of the capillary were bound with linear polyacrylamide through Si-C bonds, electroosmotic flow was not generated even at pH 7.4 with an applied voltage of +10 kV. The unbound drug bearing positive charge migrated electrophoretically from the drug-protein mixed zone toward the detection end, whereas human serum albumin did not co-migrate because of its negative charge. The bound drug migrated after it was released from the protein. As a result of an 80-nL injection of the sample solution, VER was eluted as a zonal peak with a plateau region. The VER concentration calculated from the plateau height agreed well with the unbound VER concentration determined by the conventional ultrafiltration-HPLC method, with good reproducibility (CV, < 6.23%, n = 15). The present HPCE/FA system was applied to the Scatchard analysis of VER and alpha 1-acid glycoprotein binding, and the estimated binding parameters agreed well with literature values.

Changes in epidermal growth factor receptor and the levels of its ligands during menstrual cycle in human endometrium

We examined menstrual cycle-dependent changes in the expression of human endometrial epidermal growth factor (EGF), transforming growth factor alpha (TGF alpha), and epidermal growth factor receptor (EGFR) and their mRNA using immunoblot analysis, 125I-EGF binding, and competitive reverse transcription and polymerase chain reaction (RT-PCR). We also studied their localization in the endometrial tissue by immunohistochemistry. Endometrial samples were obtained at three stages of menstruation: the early follicular stage, which exhibits low serum estradiol (E2) and progesterone (P) levels; the late follicular stage, which exhibits high E2 and low P levels; and the luteal stage, which exhibits high E2 and P levels. Immunohistochemical examination showed that EGF, TGF alpha, and EGFR were localized to the endometrial epithelium. Immunoblot analysis revealed that endometrial EGF, TGF alpha, and EGFR levels were significantly (p < 0.01) increased at the late follicular and luteal stages compared to the early follicular stage. 125I-EGF-specific binding levels at the late follicular and luteal stages were significantly (p < 0.01) higher than at the early follicular stage, consistent with the results of immunoblot analysis. Competitive RT-PCR revealed that EGF, TGF alpha, and EGFR mRNA levels were significantly (p < 0.01) higher at the late follicular and luteal stages than at the early follicular stage. Changes in EGF, TGF alpha, and EGFR mRNA levels were consistent with changes in protein levels. These findings suggest that synthesis and expression of human endometrial EGF, TGF alpha, and EGFR vary with the stage of the menstrual cycle and that their expression in the human endometrium is associated with the increase in the serum E2 but not with the increase in P levels.