Periodontal disease in the prehistoric Ipiutak and Tigara skeletal remains from Point Hope,Alaska

Two large groups of prehistoric Eskimo skeletons from Point Hope, Alaska, were evaluated for dental wear and several measures of periodontal disease. Occlusal attrition was found to increase steadily with increasing age. Crown height decreased proportionately. Assessing periodontal disease by inspecting apparent alveolar recession was judged ineffective due to possible supereruption. Infrabony pockets, the result of severe localized periodontal disease indicated that in Ipiutak people between the ages of 25 and 30, and Tigara people between 35 and 40, more dental sites were affected by periodontal disease than were not. This suggests a cultural, genetic, or dietary difference between the two groups. Male/female differences were slight in all parameters studied.     

板栗干腐病的防治研究之五

研究证明,花期防治以及及时采收、低温贮藏和快速运输等保水措施是控制板栗干腐病的较为有效的措施。     

On the Stability of Messenger RNA and Ribosomal RNA in the Brains of Control Human Subjects and Patients with Alzheimer''s Disease

The levels of the mRNAs encoding the G protein subunits GS alpha, G beta 1, and G beta 2 were measured by northern blotting in the frontal cortex and hippocampus of control subjects and of patients with a clinical and histopathological diagnosis of dementia of the Alzheimer type (DAT). There was no significant difference, in either brain region, between the control and DAT groups for any of the G protein mRNAs measured. The degree of intersubject variability was very high, e.g., GS alpha mRNA in the frontal cortex (mean optical density +/- SD) was 405 +/- 342 in the control group versus 305 +/- 207 in the DAT group. The extent of generalised RNA degradation was assessed by detecting the breakdown products of 28S rRNA. RNA degradation was present in tissue samples from every human subject studied. The extent of 28S rRNA degradation in each subject was found to be related to the levels of G protein mRNA detected. The degree of RNA degradation in human subjects was found to be very variable and unaffected by the presence of DAT. RNA degradation correlated poorly with postmortem interval and this was confirmed by a controlled study of postmortem degradation in rat tissue. The possibility that the relative hypoxia and ischaemia in patients immediately before death could influence RNA degradation is discussed. The variable extent of RNA degradation means that great care must be taken to ensure the validity of RNA analyses undertaken in human postmortem brain, particularly when techniques are employed (such as in situ hybridisation) that themselves give no indication of RNA integrity.     

Effects of chemical composition on nitrogen mineralization from green manures of seven tropical leguminous trees

Green manures from seven tropical leguminous trees were incubated with soil to determine the rates and controls of net nitrogen release. Fresh green manure (leaves and succulent twigs) was mixed with moist soil and incubated in polyethylene bags. Net N mineralization from green manures was estimated by the accumulation of extractable ammonium and nitrate minus the accumulation in soil alone. Patterns of N mineralization were complex, differed among species, and at 12 weeks ranged from 10 to 65 percent of original green-manure N. Cumulative net N mineralization was negatively correlated with initial soluble polyphenol content in the early phases of decomposition (1 through 8 weeks) and with initial lignin content in later phases (4 through 12 weeks). Neither initial percent N nor lignin: N ratio were strongly correlated with N mineralization. The best chemical index of N release was the initial polyphenol: N ratio. This study confirms previous findings that N mineralization from tropical legumes is controlled more by soluble polyphenols than by lignin or N content.     

Isolation and characterization of fluorescent Pseudomonas associated with the roots of rice and banana grown in Sri Lanka

Bacterial populations in different parts of the rhizosphere of rice and banana in Sri lanka were examined. On rice, the number of aerobic bacteria and the population of fluorescent bacteria were higher in the rhizoplane as compared to the exorhizosphere. However, the opposite was observed with banana. Percentage of fluorescent bacteria was significantly higher on banana (10.8%) than on rice from the wet and dry zones of Sri Lanka (4.3% and 2.7%, respectively). In the endorhizosphere fraction of rice, bacterial populations were very low. Fluorescent bacteria were absent.Based on 33 phenotypical tests, 89 fluorescent isolates were grouped into 5 clusters. The three major clusters covered the isolates belonging to the Pseudomonas fluorescens-putida group, whereas the remaining small clusters contained other UV-fluorescent bacteria. SDS-PAGE of total cell proteins enabled classification of the isolates into one of 12 different protein-polymorphic types. Only a partial correlation was found between the latter classification and the phenotypical one. Cyanogenesis was observed with strains of P. fluorescens only. Isolates P. fluorescens RW9S1 and P. cepacia RW5P1 displayed a potent antagonism against several fungi.     

Anticataleptic potencies of glutamate-antagonists

Summary The anticataleptic effects of non-competitive and competitive NMDA antagonists as well as those of an agonist at the allosteric glycine binding site of the NMDA receptor were tested in the catalepsy model. Some of these drugs were further tested in a reaction time task demanding rapid locomotor initiation. The results show that the non-competitive NMDA antagonists dizocilpine and memantine as well as the competitive antagonists CGP 39551, CGP 37849 and CPPene antagonized dopamine D2 receptor mediated catalepsy induced by haloperidol. D-cycloserine, a partial glycine agonist per se had no effects, but it enhanced the anticataleptic effects of dizocilpine when coadministered. However, the effects of CGP 37849 were abolished. Dopamine D1 receptor mediated catalepsy induced by SCH 23390 was antagonized by dizocilpine, memantine, CPPene, but not by CGP 37849. In the reaction time task dizocilpine, memantine and CGP 37849 were tested for their anti-akinetic and anti-bradykinetic potencies. All these compounds improved haloperidolinduced slowing of reaction time. However, they acted differentially on haloperidol-induced slowing of movement execution and decreased initial acceleration. Thus, antagonists at the NMDA receptor may have a therapeutic potential in the treatment of Parkinson's disease. Their potency can be manipulated specifically at the glycine binding site.     

Further properties of wineberry latent virus and evidence for its possible involvement in calico disease

The flexuous filamentous particles of wineberry latent virus (WLV) were found to measure 620. 12 nm and not 510. 12 nm as previously reported. Analysis of dsRNA from infected plants detected a major species of c. 5.7. 10⁶ mol. wt and minor species of lower mol. wt. Purified virus particles formed a major and a minor buoyant density component in solutions of caesium salts with densities of 1.26 and 1.25 g cm^-3 in Cs₂SO₄ and 1.30 and 1.29 g cm^-3 in CsCl. The particles contained a single nucleic acid species, presumably single stranded RNA, and a single polypeptide of estimated mol. wt 2.78. 10⁶ and 31 000 respectively. In indirect ELISA, purified particles of WLV and particles in plant sap failed to react specifically with antiserum to nine carlaviruses, 12 potexviruses, three capilloviruses or apple chlorotic leafspot closterovirus, nor was WLV found to react with several of these antisera in immunosorbent electron microscopy or immunoblots. In Marion and Olallie blackberry, WLV in mixture with raspberry bushy dwarf virus (RBDV), but not RBDV alone, induced veinal line-pattern symptoms resembling those of calico disease reported from the USA.     

Increased Noradrenergic Metabolism in the Cerebellum of the Mouse Mutant Dystonia Musculorum

Abstract: The neurological mouse mutant dystonia musculorum exhibits bizarre appendicular and truncal dystonia without known cerebellar histopathology. We evaluated striatal dopamine and cerebellar norepinephrine metabolism in this mutant and compared the results with those obtained in wild-type BALB/c and B6C3 controls. Tyrosine hydroxylase activity and dopamine metabolite levels (homovanillic acid and 3,4-dihydroxyphenylacetic acid) in the striatum of the mutant were similar to controls. Tyrosine hydroxylase activity and the steady-state level of 3-methoxy-4-hydroxyphenethyleneglycol, a metabolite of norepinephrine, in the cerebellum were 38% and 42-66%, respectively, greater in the mutant. However, the level of norepinephrine was similar (∼350 ng/g). Further, a Purkinje cell-specific marker, cGMP-dependent protein kinase, was unchanged in the mutant and no Purkinje cell pathology was observed with light microscopy. The lack of Purkinje cell derangement and similar levels of cerebellar norepinephrine and cGMP-dependent protein kinase activity suggest that increased norepinephrine metabolism in the cerebellum of this mutant is not a morphological response to gross target cell loss during morphogenesis. The observed changes may be a reaction to abnormal impulse traffic or altered input/output pathways to the mutant cerebellum during its development.     

Platelet Glutamate and Aspartate Uptake in Huntington's Disease

Abstract A possible involvement of amino acid uptake mechanisms in the etiology of the human neurodegenerative disease, Huntington's disease (HD), was investigated. Measurement of glutamate (Glu) and aspartate (Asp) uptake was performed in blood platelets, which have previously been shown to constitute a peripheral model system for central amino acid uptake processes. Analyses of Glu and Asp accumulation at 10⁻⁷ M and kinetic examination of the high affinity site for Glu indicate no significant differences between control and HD platelets. A genetically determined defect in amino acid uptake therefore does not seem to underlie the nerve cell loss observed in HD patients.     

Rate of acclimation of the tropical salt-marsh fish Cyprinodon dearborni to temperature changes

The acclimation rates of temperature changes in Cyprinodon dearborni, collected from Laguna Los Patos, Cumana, Venezuela, were determined by the critical thermal maximum method. At an increase in temperature (from 24 to 31°C) fish started to gain acclimation level after 3 hours and took 3 days to fully get up to a higher level of resistance to heat death; however, at a decrease in temperature (from 3 t to 24°C) fish began to lose its acclimation level after 12 days and required 39 days to reach a lower level of resistance to thermal death.