GABAergic neocortical neurons are resistant to NMDA receptor-mediated injury

N-methyl-D-aspartate (NMDA) receptors are thought to mediate much of the central neuronal loss produced by certain neurologic insults, including hypoxia-ischemia, hypoglycemia, and trauma. Therefore, the specific vulnerability of GABAergic inhibitory neurons to NMDA receptor-mediated toxicity might be an important determinant of the potential for epileptogenesis following these insults. We have examined the fate of GABAergic cortical neurons in mouse cell cultured neuronal population) were identified either by immunoreactivity with antisera to GABA or by autoradiography following high-affinity uptake of 3H-GABA. Cultures exposed for 5 min to 20 to 750 microM NMDA showed NMDA concentration-dependent, widespread neuronal loss. However, GABAergic neurons were relatively spared, and thus represented an enhanced fraction of neuronal survivors. These observations suggest that GABAergic cortical neurons may possess some intrinsic resistance to NMDA receptor-mediated neurotoxicity, a property which might convey an anticonvulsant "inhibitory safety factor" to neocortex against certain forms of injury.     

Cerebral blood flow and metabolism in severely head-injured children. Part 1: Relationship with GCS score, outcome, ICP, and PVI

The literature suggests that in children with severe head injury, cerebral hyperemia is common and related to high intracranial pressure (ICP). However, there are very few data on cerebral blood flow (CBF) after severe head injury in children. This paper presents 72 measurements of cerebral blood flow ("CBF15"), using the 133Xe inhalation method, with multiple detectors over both hemispheres in 32 children aged 3 to 18 years (mean 13.6 years) with severe closed head injury (average Glasgow Coma Scale (GCS) score 5.4). In 25 of the children, these were combined with measurements of arteriojugular venous oxygen difference (AVDO2) and of cerebral metabolic rate of oxygen (CMRO2). In 30 patients, the first measurement was taken approximately 12 hours postinjury. In 18 patients, an indication of brain stiffness was obtained by withdrawal and injection of ventricular cerebrospinal fluid and calculation of the pressure-volume index (PVI) of Marmarou. The CBF and CMRO2 data were correlated with the GCS score, outcome, ICP, and PVI. Early after injury, CBF tended to be lower with lower GCS scores, but this was not statistically significant. This trend was reversed 24 hours postinjury, as significantly more hyperemic values were recorded the lower the GCS score, with the exception of the most severely injured patients (GCS score 3). In contrast, mean CMRO2 correlated positively with the GCS score and outcome throughout the course, but large standard deviations preclude making predictions based on CMRO2 measurements in individual patients. Early after injury, there was mild uncoupling between CBF and CMRO2 (CBF above metabolic demands, low AVDO2) and, after 24 hours, flow and metabolism were completely uncoupled with an extremely low AVDO2. Consistently reduced flow as found in only four patients; 28 patients (88%) showed hyperemia at some point in their course. This very high percentage of patients with hyperemia, combined with the lowest values of AVDO2 found in the literature, indicates that hyperemia or luxury perfusion is more prevalent in this group of patients. The three patients with consistently the highest CBF had consistently the lowest PVI: thus, the patients with the most severe hyperemia also had the stiffest brains. Nevertheless, and in contrast to previous reports, no correlation could be established between the course of ICP or PVI and the occurrence of hyperemia, nor was there a correlation between the levels of CBF and ICP at the time of the measurements. The authors argue that this lack of correlation is due to: 1) a definition of hyperemia that is too generous, and 2) the lack of a systematic relationship between CBF and cerebral blood volume     

Supernumerary humeral heads of the biceps brachii muscle revisited

Supernumerary humeral heads of the biceps brachii muscle were found in 27 (15.4%) of 175 cadavers. They were bilateral in five cadavers and unilateral in 22 (8 left, 14 right), giving a total of 32 examples in 350 arms (9.1%). Depending on their origin and location, the supernumerary heads were classified as superior, infero-medial, and infero-lateral humeral heads. Previous studies were reviewed using this classification. The infero-medial humeral head was observed in 31 of 350 (9%) arms and was therefore the most common variation. The superior humeral head was observed in five (1.5%). The infero-lateral humeral head was the least common variation, observed only in one (0.3%) of 350 arms. A biceps brachii with three heads was observed in 27 of 350 (7.7%) arms and with four heads in five (1.4%) arms.     

The application of molecular techniques to solid tumors

Recent developments in the field of molecular biology including the sequencing of the human genome and related high throughput methodologies are presenting the diagnostic pathologist with new opportunities to expand our understanding of human disease. These techniques enable the comprehensive assessment of molecular alterations with cell populations of interest, including cancer. It will be necessary for the diagnostic pathologist to become familiar with these techniques to effectively translate their potential into the clinical environment.     

Identification of surface-exposed B-cell epitopes recognized by Haemophilus influenzae type b P1-specific monoclonal antibodies.

A panel of P1 synthetic peptides was synthesized to map the surface-exposed epitopes of Haemophilus influenzae type b outer membrane protein P1 recognized by three murine monoclonal antibodies (MAbs 7C8, 3E12, and 6B1). By using peptide-specific enzyme-linked immunosorbent assays, MAbs 6B1, 7C8, and 3E12 were shown to recognize distinct epitopes localized within residues 60 to 88, 165 to 193, and 400 to 437 of mature P1, respectively. Since MAb 7C8 was shown previously to be protective against certain H. influenzae type b subtypes in the infant rat model of bacteremia, its cognate epitope was further characterized by using truncated peptide analogs. Fine mapping of the 7C8 epitope by competitive inhibition studies revealed that it was localized within residues 184 and 193.     

Expression of the alpha1D subunit of the L-type voltage gated calcium channel in human liver

Calcium channel blocker is useful for a variety of purposes and is effective for preventing hepatitis elicited by different inducers, suggesting its possible clinical application for treating hepatitis. The alpha1-subunit of the dihydropyridine-sensitive L-type calcium channel is a target of calcium channel blocker. For clinical application of calcium channel blocker, it is important to analyze the expression of the L-type calcium channel in the liver. However, the subtype of the L-type calcium channel alpha1-subunit expressed in the liver was not known. In the present study, the alpha1-subunit of the calcium channel expressed in human liver was systematically analyzed. The alpha1D subunit of the dihydropyridine-sensitive L-type voltage gated calcium channel is expressed relatively strongly in the liver and may play an important role in the liver.     

Detection of YMDD motif mutants by oligonucleotide chips in lamivudine-untreated patients with chronic hepatitis B virus infection

Lamivudine, a nucleoside analogue, has been used widely as an effective antiviral agent for the treatment of patients with chronic hepatitis B virus (HBV) infection. However, the YMDD motif mutation of HBV polymerase resistant to lamivudine occurs very frequently after long term therapy. We developed an oligonucleotide chip for the detection of YMDD motif mutants resistant to lamivudine and investigated the prevalence of the mutants in patients with chronic HBV infection who had not been treated by lamivudine before. Forty patients who had not been treated with lamivudine were included in this study. Serum samples were tested by the oligonucleotide chips designed for detection of wild-type YMDD motif, M552V and M552I. Samples were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. M552I mutants were detected by the oligonucleotide chips in 7.5% (3/40) of chronic HBV infected patients (2 chronic hepatitis and 1 cirrhosis). The results were in accordance with those of RFLP. YMDD motif mutants occur as natural genome variabilities in patients with chronic HBV infection who had not been treated with lamivudine before. Oligonucleotide chip technology is a reliable and useful diagnostic tool for the detection of mutants resistant to antiviral therapy in chronic HBV infection.     

Morphine prevents glutamate-induced death of primary rat neonatal astrocytes through modulation of intracellular redox

This study is designed to investigate the effect of morphine on glutamate-induced toxicity of primary rat neonatal astrocytes. Glutamate decreases the intracellular GSH level, and thereby induces cytolysis of astrocytes and C6 glial cells accompanied by apoptotic features. Glutamate-induced cytotoxicity is protected by morphine and antioxidants such as GSH and NAC, whereas MK-801, an antagonist of glutamate receptor NMDA does not protect astrocytes against glutamate toxicity. Also, morphine antagonist, naloxone, as well as selective ligands for opioid receptor subtypes, including DAMGO, DPDPE, and U69593, do not inhibit the protective effect of morphine on glutamate-induced cytotoxicity. Morphine significantly prevents the depletion of GSH by glutamate and thereby inhibits the generation of H2O2 in a dose-dependent manner. Furthermore, morphine prevents the change of mitochondrial permeability transition by glutamate. Taken together, we suggest that morphine protects the primary rat neonatal astrocytes from glutamate toxicity via modulation of intracellular redox status.     

Increase in gap junctional intercellular communication by high molecular weight hyaluronic acid associated with fibroblast growth factor 2 and keratinocyte growth factor production in normal human dermal fibroblasts

The effects of different molecular weights of hyaluronic acid (HA), a major component of extracellular matrix, on gap junctional intercellular communication (GJIC) in normal human dermal fibroblasts (NHDF cells) were investigated. NHDF cells were cultured for 4 days with different molecular weights of HA and then the extent of GJIC was assessed by the scrape-loading dye transfer method, using Lucifer yellow. The area of dye transfer was greater in the dishes coated with HA than in those to which HA was added. Thus, NHDF cells cultured on surfaces coated with high molecular weight (HMW) HA (MW, 800 kDa) showed greatly enhanced GJIC. Furthermore, another aim of this study was to evaluate the effects of different molecular weights of HA on the production of FGF-2 and KGF, because both are important cytokines produced by NHDF cells. When FGF-2 and KGF cultured levels of cell extracts and media were determined by ELISA, both levels were significantly enhanced when cells were grown on plates coated with HMW HA. This finding indicated that the function of gap junction channels in NHDF cells grown on plates coated with HMW HA may promote the biosynthesis of growth factors such as FGF-2 and KGF.