Activation of poly(ADP-ribose) polymerase in the rat hippocampus may contribute to cellular recovery following sublethal transient global ischemia

We have investigated the role of poly(ADP-ribose) polymerase (PARP) activation in rat brain in a model of sublethal transient global ischemia. Adult male rats were subjected to 15 min of ischemia with brain temperature reduced to 34 degrees C, followed by 1, 2, 4, 8, 16, 24, and 72 h of reperfusion. PARP mRNA expression was examined in the hippocampus using quantitative RT-PCR, northern blot analysis, and in situ hybridization. Protein expression was assessed using western blot analysis. PARP enzymatic activity was investigated by measuring nuclear [3H]NAD incorporation. The presence of poly(ADP-ribose) polymers was assessed immunocytochemically. Although PARP mRNA and protein expressions were not altered after ischemia, enzymatic activity was increased 4.37-fold at 1 h (p < 0.05 vs. sham) and 1.73-fold (p < 0.05 vs. sham) at 24 h of reperfusion. Immunostaining demonstrated the presence of poly(ADP-ribose) polymers in CA1 neurons. Cellular NAD+ levels were not significantly altered at any time point. Furthermore, systemic administration of 3-aminobenzamide (30 mg/kg), a PARP inhibitor, prevented the increase in PARP activity at 1 and 24 h of reperfusion, significantly decreased the number of surviving neurons in the hippocampal CA1 region 72 h after ischemia (p < 0.01 vs. sham), and increased DNA single-strand breaks assessed as DNA polymerase I-mediated biotin-dATP nick-translation (PANT)-positive cells (p < 0.01 vs. sham). Furthermore, using an in vitro DNA repair assay, 3-aminobenzamide (30 mg/kg) was shown to block DNA base excision repair activity. These data suggest that the activation of PARP, without subsequent NAD+ depletion, following mild transient ischemia may be neuroprotective in the brain.

Overexpression of the cell death suppressor Bcl-w in ischemic brain: implications for a neuroprotective role via the mitochondrial pathway

Bcl-w is a newly described cell death suppressor member of the Bcl-2 gene family. As these genes may have a role in the outcome of ischemic brain injury, the regional expression of Bcl-w protein in rat brain was examined at 6 to 72 hours after 90 minutes of transient middle cerebral artery occlusion. Bcl-w protein, although constitutively expressed at low levels in nonischemic brain, was found to be overexpressed in ischemic brain at all time points studied. Up-regulation of Bcl-w protein was particularly abundant in the penumbral region of the cortex and mainly in cells lacking DNA fragmentation. In the cortical penumbra, Bcl-w protein was detected predominantly in neurons and showed mitochondrial localization, as determined using double-label immunohistochemistry. Bcl-w expression was also detectable, to a lesser extent, in reactive astrocytes in the infarct border zone and in microvessel walls in the infarct regions. At the mechanistic level, incubation of isolated brain mitochondria with the addition of recombinant Bax or high concentration of calcium resulted in release of cytochrome c from the mitochondria. In the presence of recombinant Bcl-w protein, however, the release of cytochrome c induced by Bax or calcium was largely inhibited. Further, recombinant Bcl-w protein inhibited calcium-induced loss of mitochondrial transmembrane potential, indicative of permeability transition, in a dose-dependent manner. These results suggest that Bcl-w may be an endogenous neuroprotectant against ischemic neuronal death and that, like its analogues such as Bcl-2 and Bcl-x-long, Bcl-w may achieve this protection via the mitochondrial death-regulatory pathway.

Support for linkage of familial combined hyperlipidemia to chromosome 1q21-q23 in Chinese and German families

We examined familial combined hyperlipidemia (FCHL) families from nonisolated regions in Germany and China to see if we could corroborate support for a chromosome 1q FCHL locus in more general populations. We recruited 24 German families with 137 members, 92 of whom met the criteria of affected in terms of the low density lipoprotein (LDL) and triglyceride levels in excess of the 90th percentile for age and gender. In China, we recruited 12 families with a total of 81 members. All affected persons had total cholesterol concentrations >240 mg/dl and triglyceride concentrations >250 mg/dl. We examined the markers APOA2, D1S1677, D1S104, D1S194, D1S426, and D1S196. Two-point linkage analysis allowing for heterogeneity gave a maximum linkage of disorder score (HLOD) of 2.60 right over D1S194, estimating the proportion of linked families at 36%. This marker is adjacent to D1S104. The evidence for linkage was roughly the same both in the German (HLOD 1.40) and Chinese families (HLOD 1.52). Marker D1S194 is close to the retinoid X receptor (RXR) gene locus, which was found to be linked to triglyceride levels in an earlier twin study from our laboratory. We interpret our observations as encouraging support for the recent findings indicating the presence of a gene for FCHL on chromosome 1q. Furthermore, since DIS194 is adjacent to the gene for the RXR, we suggest that RXR is an attractive candidate for involvement in FCHL.

Mass spectrometric study of gamma-aryl-alpha,-gamma-diethoxy-alpha, beta-butenolides

Electron impact mass spectra of eight of the title compounds are reported. Abundant fragment ions were produced under electron impact (EI) conditions and, with one exception, the ($¿hbox¿ArC¿¿equiv$ O) ions were the base peaks. The EI fragmentation mechanisms of two representative compounds were studied with the aid of high-resolution and mass-analyzed ion kinetic energy spectrometry (MIKES) data. The M(+) ions fragment to give both an odd-electron ion and an even-electron fragment ion. Two H-atom rearrangements proceeding via four-membered ring intermediates and three losses of CO through i- and alpha-fragmentations were observed under EI. On comparing fragmentations under EI conditions with those under FAB conditions for two of the compounds, the fragmentation mechanisms were reasonably similar, with additional fragmentations rationalized in terms of the ionization proton being located on the oxygen atom of the beta-ethoxy group.

[Linkage of familial combined hyperlipidemia to chromosome 1q21-23 in Chinese and German families]

OBJECTIVE

To examine familial combined hyperlipidemia (FCHL) families from nonisolated regions in China and Germany to see if we could corroborate support for a chromosome 1q FCHL locus in more general populations.

METHODS

We recruited 24 German families with 133 members and 12 Chinese families with a total of 81 members in China. The markers ApoA2, D1S1677, D1S104, and D1S194 were examined by multipoint linkage analysis.

RESULTS

Multipoint linkage analysis allowing for heterogeneity gave a maximum LOD score (HLOD) of 1.97 right over D1S194, estimating the proportion of linked families at 17%. This marker was adjacent to D1S104. The evidence for linkage was roughly the same both in the German (13%, HLOD(D1S194) = 1.08) and Chinese families (proportion of linked families 26%, HLOD(D1S194) = 0.97).

CONCLUSION

In the light of the relatively small numbers and the heterogeneity our populations represent, we interpret our observations as encouraging support for the recent findings indicating the presence of linkage for FCHL on chromosome 1q21-23.

Early detection of DNA strand breaks in the brain after transient focal ischemia: implications for the role of DNA damage in apoptosis and neuronal cell death

Using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL), we investigated the evolution of DNA strand breaks, a marker of DNA damage, in rat brain after 1 h of middle cerebral artery occlusion and various durations of reperfusion. DNA single-strand breaks (SSBs) detected by PANT were present in neurons after as little as 1 min of reperfusion. Numbers of neurons containing an SSB increased progressively in the ischemic core but decreased in the ischemic penumbra after 1 h of reperfusion. DNA double-strand breaks (DSBs) detected by TUNEL were first seen in neurons after 1 h of reperfusion, and their numbers then increased progressively in the ischemic core, with a regional distribution similar to that of SSBs. However, the number of SSB-containing cells was greater than that of DSB-containing cells at all time points tested. SSB-containing cells detected within the first hour of reperfusion were exclusively neuronal and exhibited normal nuclear morphology. At 16-72 h of reperfusion, many SSB- and DSB-containing cells, including both neurons and astrocytes, showed morphological changes consistent with apoptosis. Gel electrophoresis of DNA isolated from the ischemic core showed DNA fragmentation at 24 h, when both SSBs and DSBs were present, but not at 1 h, when few DSBs were detected. These results suggest that damage to nuclear DNA is an early event after neuronal ischemia and that the accumulation of unrepaired DNA SSBs may contribute to delayed ischemic neuronal death, perhaps by triggering apoptosis.

Ubiquitin C-terminal hydrolase is an immediate-early gene essential for long-term facilitation in Aplysia

The switch from short-term to long-term facilitation of the synapses between sensory and motor neurons mediating gill and tail withdrawal reflexes in Aplysia requires CREB-mediated transcription and new protein synthesis. We isolated several downstream genes, one of which encodes a neuron-specific ubiquitin C-terminal hydrolase. This rapidly induced gene encodes an enzyme that associates with the proteasome and increases its proteolytic activity. This regulated proteolysis is essential for long-term facilitation. Inhibiting the expression or function of the hydrolase blocks induction of long-term but not short-term facilitation. We suggest that the enhanced proteasome activity increases degradation of substrates that normally inhibit long-term facilitation. Thus, through induction of the hydrolase and the resulting up-regulation of the ubiquitin pathway, learning recruits a regulated form of proteolysis that removes inhibitory constraints on long-term memory storage.

Electrophoretic demonstration of high molecular weight fibrin degradation products persisting in chronic subdural hematomas

Local hyperfibrinolysis plays an important role in the pathogenesis of chronic subdural hematoma (CSH). The purpose of this study is to elucidate the nature of the local hyperfibrinolysis in CSH, by comparing the pattern of fibrin/fibrinogen degradation product (FDP) of hematomas with that of purified fibrin clots digested by plasmin in vitro. Forty-seven hematoma samples were subjected to the analysis. FDPs of CSH and the purified fibrin clots digested by plasmin for different incubation times were identified using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immuno-blotting, and then quantified by densitometry. The effect of alpha-2 plasmin inhibitor (A2-PI) on the degradation process was also studied. The FDP pattern of CSH was similar to those of purified fibrin digested by plasmin for 0.75-2 h. The FDP composition of CSH was closest to that of purified fibrin digested for 1 h. By adding the physiological concentration of A2-PI at the second hour, further degradation of high molecular weight FDPs was inhibited and the early FDP pattern persisted after 24 h. Local hyperfibrinolysis in CSHs is characterized by incomplete fibrinolysis, which occurs only on the solid fibrin clot, and is arrested in the liquid hematoma. As a result, high molecular weight FDPs persist in CSHs for weeks or months in the hematoma. A2-PI seems to play an important role in producing this unique FDP pattern in CSH.

[Clinical studies on changes in sexual hormones and estrogen receptor in patients with gynecomastia]

Levels of serum testosterone (T), estradiol (E2), and estrogen receptor (ER) in the tissue were detected by radioimmunoassay and immunohistochemical method (ABC technique) in 46 patients with gynecomastia. The results showed that rise of E2 and E2/T is a whole-body etiologic factor of hypertrophy of male breast, and the positive rate of ER is an important local etiologic factor of gynecomastia. E2 and ER have aosynergism effect on onset and development of gynecomastia and cause the ductal cell hyperplasia of male breast. It should be alerted whether it can cause male breast cancer.

Automatic specklegram fringe analysis by using symmetry evaluation of the Theta-scanning function

New approaches are applied to overcome the difficulty of accurate angle measurements in specklegram information processing by introducing a prism rotator for compensation and by using symmetry evaluation. Together with slit scanning and the fast Fourier transform procedure, speckle random noise has been effectively suppressed, and accurate measurements of Theta and s are achieved. The method we present makes it possible to process the specklegram information automatically. The experimental setup is described in detail. The principles and experimental curves are given.