bluuebunny/crossref_metadata_2025_split huggingface dataset:
ONTOGENETIC DEVELOPMENT OF A PHOSPHODIESTERASE ACTIVATOR AND THE MULTIPLE FORMS OF CYCLIC AMP PHOSPHODIESTERASE OF RAT BRAIN
Authors: Strada S. J. , Uzunov P. , Weiss B. 
Published: December 2006

Abstract— The activity of cyclic AMP phosphodiesterase of rat cerebral homogenates increased several‐fold between 1 and 60 days of age. Enzyme activity in the cerebellum, on the other hand, did not increase during this period. A kinetic analysis of the phosphodiesterase activity revealed evidence for multiple forms of the enzyme and indicated that the postnatal increase in phosphodiesterase activity of rat cerebrum was due almost exclusively to the high Km enzyme. In cerebellum, the ratio of the high and low Km enzyme remained fairly constant during ontogenetic development.Physical separation of the phosphodiesterases contained in 100,000 g soluble supernatant fractions of sonicated brain homogenates by polyacrylamide disc gel electrophoresis confirmed the presence of multiple enzyme forms. In adult rats we found six distinct peaks of phosphodiesterase activity (designated I to VI according to the order in which they were eluted from the column) in cerebellum and 4 forms of the enzyme (Peaks I through IV) in cerebrum. Brains of newborn rats had a different pattern and ratio of phosphodiesterase activities. For example, Peak I phosphodiesterase was undetectable in cerebrum or cerebellum of newborn rats. Moreover, in the cerebellum of newborn rats Peak II was the dominant peak whereas in the cerebellum of adult rats Peak III was the largest peak. A comparison of the multiple forms of phosphodiesterase from the cerebrum of newborn and adult animals suggested that the postnatal increase in phosphodiesterase activity previously seen in crude homogenates was due largely to an increase in a high K, Peak II phosphodiesterase. The ratios of activities of the other peaks and their sensitivities to an activator of phosphodiesterase were similar in newborn and adult rats.An endogenous heat‐stable activator of phosphodiesterase was found in cerebrum, cerebellum and brain stem. In newborn rats, the cerebellum contained several‐fold less activity of this activator than did cerebrum or brain stem. However, the activity of this activator increased with age in the cerebellum and would appear to have decreased postnatally in cerebrum and brain stem.These results suggest that some multiple forms of phosphodiesterase can develop independently and that changes in activities of these phosphodiesterases may occur by increases in the quantity of enzyme or by changes in the quantity of an endogenous activator of phosphodiesterase.
SUBUNIT STRUCTURE AND KINETIC PROPERTIES OF 4‐AMINOBUTYRATE‐2‐KETOGLUTARATE TRANSAMINASE PURIFIED FROM MOUSE BRAIN
Authors: Schousboe A. , Wu J.‐Y. , Roberts E. 
Published: December 2006

Abstract— The effects of divalent metal ions, sulfhydryl reagents, carbonyl trapping reagents, substrate analogs, and organic solvents on purified mouse brain 4‐aminobutyrate‐2‐ketoglutarate transaminase (EC 2.6.1.19) and the subunit structure of this enzyme were studied. Of the metal ions tested, Hg2+ was found to be the most potent inhibitor inhibiting the enzyme 50 percent at a concentration of 0‐7 μM. The order of decreasing inhibitory potency for the divalent metal ions was: Hg2+± Cd2+± Zn2+± Cu2+± Co2+± Ba2+± Sr2+± Ni2+± Mn2+± Ca2+± Mg2+. p‐Chloromercuribenzoale was the most potent inhibitor among the sulfhydryl reagents tested inhibiting the enzyme to the extent of 50 per cent at 0‐5 μM 3‐Mercaptopropionic acid was found to be a competitive inhibitor for GABA and non‐competitive for 2‐ketoglutarate. The Ki, value was estimated to be 13 μM. Aminooxyacetic acid was the most potent inhibitor of the carbonyl trapping agents with a K, value of 0‐06 μM. being competitive with GABA and non‐competitive with 2‐ketoglutarate. Hydroxylamine and hydrazine were the next most potent compounds in this group. Of a series of substrate analogs and metabolites tested, only acetic acid, propionic acid, butyric acid, glutamic acid, adipic acid, pimelic acid and 2‐ketoadipic acid inhibited the enzyme to a significant extent. Dioxan inhibited the enzyme 50 per cent at a concentration of 5 per cent (v/v) whereas methanol and ethanol only inhibited 5‐10 per cent at 10 per cent (v/v) concentration.A spectrum of the native enzyme at pH 7‐2 showed maxima at 278 nm. 330 nm and 411 nm. Treatment of the enzyme with aminooxyacetic acid or 3‐mercaptopropionic acid caused the maximum at 411 nm to disappear.Sodium dodecyl sulfate polyacrylamide gel electrophoresis of the enzyme revealed two protein bands. The molecular weights of these two subunits were determined to be 53.000 and 58,000, respectively.
RNA‐DNA HYBRIDIZATION STUDIES WITH UNIQUE MOUSE DNA SEQUENCES1
Authors: Wintzerith M. , Mori K. , Mandel P. 
Published: December 2006

Abstract— Unique mouse DNA sequences (not reassociated at cot 200) were prepared and hybridized with RNA fractions extracted at different temperatures with phenol from brain, liver and plasmocytoma cells. The hybridizations were carried out in liquid media, and the RNA‐DNA hybrids formed were separated on hydroxyapatite columns. The stringency of hybridization was measured by the sensitivity of the hybrids towards nuclease St, and by the Tm's of the RNA‐DNA hybrids.A tissue specificity of RNA transcription has been found. Brain RNA's seemed to be more complex than those of liver. Brain RNA fraction I (primarily of cytoplasmic origin) hybridized to unique DNA sequences more efficiently than RNA fractions II + III (enriched in nuclear messenger RNA's) whereas the reverse was true for liver and plasmocytoma cell RNA.
BIPHASIC MYELINATION AND THE FATTY ACID COMPOSITION OF CEREBROSIDES AND CHOLESTEROL ESTERS IN THE DEVELOPING CENTRAL NERVOUS SYSTEM OF THE DOMESTIC PIG
Authors: Sweasey D. , Patterson D. S. P. , GLANCY E. M. 
Published: December 2006

Abstract— The chemical composition of four parts of the CNS (cerebrum, cerebellum, brain stem and spinal cord) was determined in 107 pigs at 11 stages of fetal and postnatal development and also in 6 adults. In cerebrum, cerebellum and brain stem, but not in spinal cord, the rate of increase in weight and the rates of change in lipid content slowed down for a period of about 10 days before and after birth. Cholesterol esters and desmosterol were only found in progressively decreasing amounts during the fetal stages of development and together with DNA these were exceptions to the general increases in the tissue concentrations and total amounts of other components during the period studied.The onset of myelination, as measured by calculated daily increases in tissue contents of cerebroside took place between 70 and 80 days conceptual age and there were two peaks of activity, the first occurring 2 weeks before and the second 3 weeks after birth. Unlike the rate curve for total spinal cord weight the biphasic accumulation of DNA was not synchronous with myelin lipid accretion and the earlier prenatal DNA peak probably denotes proliferation of oligodendrocytes. The two phases of myelination are discussed in relation to an observed generalized pause in development immediately before and after birth.Fatty acid analysis of cerebrosides indicated that, in spinal cord, chain elongation and desaturation are associated with myelination and continue with increasing activity until maturity. Consequently there was a progressive decrease in the proportion of saturated fatty acids. The fatty acid components of cholesterol esters in the developing pig were shown to be similar to those found during development in the CNS of other species but different from those found in demyelinating conditions.
ON THE RELEVANCE OF PREFERENTIAL INCREASES OF MESOLIMBIC VERSUS STRIATAL DOPAMINE TURNOVER FOR THE PREDICTION OF ANTIPSYCHOTIC ACTIVITY OF PSYCHOTROPIC DRUGS
Authors: Waldmeier P. C. , Maítre L. 
Published: December 2006

Abstract— Drugs possessing (chlorpromazine, haloperidol, clozapine, thioridazine and sulpiride) or lacking (benzoctamine and perlapine) antipsychotic activity were compared with respect to their ability to enhance x‐methyl‐p‐tyrosine‐induced dopamine disappearance from the mesolimbic area and corpus striutum of rat brain. In addition, their effects on the endogenous concentrations of homovanillic (HVA) and 3.4‐dihydroxyphenylacetic (DOPAC) acids in these two brain areas were determined.Some of the drugs enhanced dopamine disappearance in the mesolimbic area more than in the striatum. The most active in this respect were sulpiride. perlapine and chlorpromazine. By contrast, haloperidol was slightly more active in the striatum than in the mesolimbic area.None of the drugs was more efficient in elevating HVA levels in the mesolimbic area than in the striatum. However, there were large differences in the relative extent of the HVA increases in the two regions. Benzoctamine, perlapine and chlorpromazine increased HVA concentrations in the mesolimbic area nearly as much as in the striatum. Thioridazine and haloperidol, however, elevated striatal HVA much more effectively.Haloperidol and clozapine increased the DOPAC concentration in both areas to about the same extent. The other drugs were more active in the striatum. The largest difference between both regions was shown by chlorpromazine.Perlapine and benzoctamine, both lacking antipsychotic activity, produced much larger increases of HVA than of DOPAC. This is in contrast to the results obtained with true neuroleptics and may reflect an involvement of release phenomena in the action of these two drugs on dopamine metabolism.These results suggest that a preferential increase of dopamine turnover in the mesolimbic area is not necessarily linked to a better ratio of antipsychotic activity vs. extrapyramidal side effects. Moreover, an antiacetylcholine component of dopamine receptor blocking drugs does not seem to be a prerequisite for preferential activity on dopamine turnover in the mesolimbic system.
RADIOIMMUNOASSAY OF METHIONINE‐AND LEUCINE‐ENKEPHALINS IN REGIONS OF RAT BRAIN AND COMPARISON WITH ENDORPHINS ESTIMATED BY A RADIORECEPTOR ASSAY
Authors: Gros C. , Pradelles P. , Rouget C. , Bepoldin O. , Dray F. , Fournie‐Zaluski M. C. , Roques B. P. , Pollard H. , Llorens‐Cortes C. , Schwartz J. C. 
Published: December 2006

Abstract— Radioimmunoassays (RIAs) selective for methionine‐enkephalin (Met‐ENK) and leucineenkephalin (Leu‐ENK) have been developed using competition towards binding of 10 pM 125I‐enkephalins to antibodies raised in rabbits against ENKs coupled to ovalbumin with carbodiimide. The high sensitivity of the RIAs (IC50 0.57 nm and 0.55 nm for Met‐ and Leu‐ENK, respectively) allowed estimation of the enkephalin content in extracts of all rat brain regions. Regional levels are compared with those determined on the same extracts by a radioreceptor assay (RRA) using competition towards binding of 5 nm [3H]Leu‐ENK to rat striatal membranes. Optimal conditions for killing the animals and extracting the endorphins have been carefully investigated: killing by rapid microwave irradiation was not found necessary as long as brain regions were homogenized into 0.1 n‐HCl before deproteinization.Marked differences both in total endorphins (RRA) and ENKs (RIA) between regions are observed with similar ranking of the various regions: highest levels are found in striatum and hypothalamus and lowest in cerebellum and hippocampus. In each region the total ENK levels (RIA) represent only 2–13% of the total endorphins (RRA) suggesting the presence of large amounts of endorphins other than the ENKs.
BIOCHEMICAL CORRELATES OF TRANSMISSION MEDIATED BY GLUTAMATE AND ASPARTATE
Authors: Nadler J. V. , White W. F. , Vaca K. W. , Perry B. W. , Cotman C. W. 
Published: December 2006

Abstract— Glutamate and aspartate probably serve as transmitters of hippocampal perforant path and commissural afferents, respectively. We therefore used slices of hippocampal regions to evaluate certain biochemical properties as markers for sites of transmission mediated by these amino acids. In these studies content and accumulation of glutamate and aspartate were compared with their Ca2+‐dependent effluxes.Hippocampal regions varied little in their contents of glutamate and aspartate, but slices of regio superior and dentate gyrus accumulated and released more of each than slices of regio inferior. A commissurotomy or bilateral entorhinal lesion altered Ca2+‐dependent efflux and accumulation in the same direction, but did not affect the glutamate or aspartate content of any hippocampal region. Elimination of hippocampal mossy fibers reduced the Ca2+‐dependent efflux of glutamate and probably aspartate from slices of dentate gyrus, but not of regio inferior, where most mossy fiber synapses are located. The mossy fibers appeared relatively deficient in aspartate in both strains tested, but only in Purdue‐Wistar rats were they enriched in glutamate. Removal of the perforant path input to the fascia dentata did not significantly change the activity of any of the enzymes most actively involved in glutamate synthesis.These results suggest that accumulation or high affinity transport of glutamate or aspartate can be employed to localize afferents which use these amino acids as transmitters, although it is not so reliable or selective a marker as Ca2+‐dependent efflux. Enrichment in either glutamate or aspartate content or in the activity of enzymes which synthesize them is not a reliable marker. Neither amino acid is likely to be used as a transmitter by the hippocampal mossy fibers.
A COMPARISON OF THE AXONAL TRANSPORT OF TAURINE AND PROTEINS IN THE GOLDFISH VISUAL SYSTEM
Authors: Ingoglia N. A. , Sturman J. A. , Rassin D. K. , Lindquist T. D. 
Published: December 2006

Abstract— Radioactive cystathionine, a metabolic precursor of taurine, was injected into the right eye of goldfish. At various times after injection the retina and both optic tecta were extracted with trichloroacetic acid (TCA) and the amount and nature of the radioactivity was determined. Radioactive taurine and inorganic sulfate were present in the TCA‐soluble extract of retina and radioactive taurine and a small amount of inorganic sulfate was found in the contralateral optic tectum. That taurine is migrating intraaxonally and is not diffusing in extraaxonal spaces is suggested from experiments in which the migration of taurine was compared with that of [14C]mannitol, used here as a marker of extracellular diffusion. In the time studied (up to 15 h) mannitol did not migrate to the tectum, whereas taurine was detectable in the tectum as early as 8 h after injection. Since intra‐axonal diffusion of amino acids and other small molecules in this system has been ruled out, it is likely that taurine is being transported axonally.The axonal transport of taurine was found to be similar to the fast component of protein transport because: (1) their rates of transport are similar, (2) the transport of both is blocked by the protein synthesis inhibitor cycloheximide, (3) vinblastine, which disrupts neurotubules, appears to have similar effects on both protein and taurine transport, and (4) both rapidly transported proteins and taurine remain mostly intra‐axonal once they have been transported to the tectum. Taurine and proteins differ in that rapidly transported proteins are primarily paniculate in nature and localized to a large extent in nerve endings, while taurine is primarily in a soluble fraction and is present in nerve endings only in trace amounts.We suggest that taurine may be loosely linked to a newly synthesized protein in the soma and is then transported along with that protein on a similar conveying mechanism in the axoplasm.
EFFECT OF OLIGEMIA ON REGIONAL METABOLITE LEVELS IN CAT BRAIN
Authors: Welsh F. A. , O'Connor M. J. , Marcy V. R. 
Published: December 2006

Abstract— Incomplete cerebral ischemia (oligemia) was produced in cat by carotid occlusion combined with arterial hypotension. Lowering arterial pressure to 50–60 Torr for 20 min caused marked alterations of the ATP, phosphocreatine, and lactate content of subcortical white matter. In contrast, metabolite levels in cerebral cortex and caudate nucleus were only moderately perturbed from control values. More severe oligemia resulted when arterial pressure was lowered to 30 Torr for 20 min following carotid occlusion. Metabolite levels in cortex, caudate nucleus, and white matter were greatly altered from control. In the gray matter there was regional heterogeneity of metabolic alteration, as evidenced from the pattern of NADH tissue fluorescence. The cortex contained micro‐patches (0.1mm) of increased NADH, which frequently exhibited a columnar orientation.These findings demonstrate two distinct types of cerebral inhomogeneity of metabolic failure with reduced blood flow; white matter fails before gray matter, and there is micro‐heterogeneity of metabolic failure in the gray matter.
Medication Costs: The Role Physicians Play with Their Senior Patients
Authors: Sue Beran Mary , Laouri Marianne , Suttorp Marika , Brook Robert 
Published: December 2006

OBJECTIVES: To determine how often primary care physicians discuss medication costs with their senior patients and what cost‐reducing strategies they employ.DESIGN: Cross‐sectional, random‐sample mail questionnaire.SETTING: State of California.PARTICIPANTS: Six hundred seventy‐eight of 1,098 (62%) internal medicine and family practice physicians selected from the American Medical Association Masterfile.MEASUREMENTS: Main outcomes included frequency of cost discussions with senior patients in the previous 30 days and choice of cost‐reducing strategy when a senior expresses financial difficulty with medication costs.RESULTS: Forty‐three percent of physicians reported discussing medication cost with at least half of their senior patients in the previous 30 days. Patients initiated most of these discussions. Forty percent reported that, at least one time in the previous 30 days, they had not discussed cost but wished they had. The most common reason given was “I ran out of time” (36%). Physicians with high perceived knowledge of medication costs were more likely to discuss cost (odds ratio (OR)=3.49, 95% confidence interval (CI)=1.66–7.3) versus low perceived knowledge, but this trend was not seen in physicians who scored high on actual knowledge of medication costs (OR=0.78, 95% CI=0.43–1.43) versus low actual knowledge. The most common cost‐reducing strategies were generic substitution (33%) and offering samples (25%).CONCLUSION: The frequency of medication cost discussions between physicians and senior patients is low, and when it occurs, is often initiated by patients. Physicians' perception of their knowledge of medication costs may be an important factor in initiating cost discussions.
The Association Between Serum Folate Levels and Periodontal Disease in Older Adults: Data from the National Health and Nutrition Examination Survey 2001/02
Authors: Yu Yau‐Hua , Kuo Hsu‐Ko , Lai Yu‐Lin 
Published: December 2006

OBJECTIVES: To assess the relationship between serum folate levels and periodontal disease in older adults.DESIGN: Population‐based cross‐sectional study.SETTING: National Health and Nutritional Examination Survey 2001/02.PARTICIPANTS: Eight hundred forty‐four dentate elderly subjects aged 60 and older (mean age 70.6) who completed a periodontal examination and laboratory test for serum folate levels.MEASUREMENTS: Periodontal examination, including probing depth and attachment loss, was performed. Periodontal disease was defined as having at least 10% of sites with clinical attachment loss of more than 4 mm and at least 10% sites with probing depth of more than 3 mm. Serum folate levels were measured using a commercially available radioprotein binding assay kit.RESULTS: After controlling for demographics, educational level, body mass index, bleeding on probing, and probing sites, the odds ratio for periodontal disease was 0.74 (95% confidence interval=0.59–0.93) for each standard deviation increase in natural‐log‐transformed folate levels. After additionally controlling for levels of vitamin B12 and homocysteine, chronic diseases (hypertension, diabetes mellitus, heart disease, and stroke), and health behaviors (smoking status and alcohol consumption), the negative association between folate level and periodontal disease remained statistically significant and essentially unchanged. There was no effect modification of sex on the association between serum folate levels and periodontal disease.CONCLUSION: A low serum folate level was independently associated with periodontal disease in older adults. The results suggest that serum folate levels, important indicators of periodontal disease in older adults, may provide an important clinical target for intervention to promote oral health.
Treatment and Prevention of Depression After Surgery for Hip Fracture in Older People: Randomized, Controlled Trials
Authors: Burns Alistair , Banerjee Sube , Morris Julie , Woodward Yvonne , Baldwin Robert , Proctor Rebekah , Tarrier Nicholas , Pendleton Neil , Sutherland Deborah , Andrew Glynne , Horan Mike 
Published: December 2006

OBJECTIVES: To evaluate the effect of a psychiatric intervention in treating depression (treatment study) and the effect of a psychological treatment in preventing depression (prevention study) after hip fracture in older people.DESIGN: Two linked randomized, controlled trials.SETTING: Orthopedic units in Manchester, England.PARTICIPANTS: Two hundred ninety‐three older people who had undergone surgery for a fractured hip: 121 in the treatment study and 172 in the prevention study.MEASUREMENTS: The Geriatric Depression Scale and Hospital Anxiety and Depression Scale for mood, functional tests for mobility and pain measures.RESULTS: There was a slight reduction in depressive symptoms in the active arm of the treatment study. In the prevention study, there was no significant difference in incident depression between the psychological intervention and treatment as usual. There were no differences in the functional and pain outcomes.CONCLUSION: The results from these two randomized, controlled trials show that, after hip fracture surgery, no statistically significant benefits can be achieved from a psychiatric intervention in people who are depressed or a psychological intervention to prevent the onset of depression.
Preoperative Immunosuppressive Therapy and Surgery as a Treatment for Anal Furunculosis
Authors: KLEIN ARNAUD , DENEUCHE AYMERIC , FAYOLLE PASCAL , HIDALGO ANTOINE , SCOTTI STEFANO , ZYLBERSTEIN LUCA , DESBOIS CHRISTOPHE , TESSIER DOMINIQUE , MOISSONNIER PIERRE , VIATEAU VÉRONIQUE 
Published: December 2006

Objectives—To evaluate the efficacy of combining preoperative immunosuppressive therapy with surgical excision for treatment of anal furunculosis (AF) in dogs.Study Design—Retrospective study.Animals—Dogs (n=25) with stages 1–4 AF.Methods—Preoperative immunosuppressive therapy was either cyclosporine A (CyA) alone or in combination with ketoconazole (Group 1; n=18), or azathioprine combined with prednisolone (Group 2; n=7). Surgical excision of residual draining tracts, cryptectomy, and anal sacculectomy were performed. Only dogs with postoperative clinical follow‐up exceeding 9 months were retained for the study.Results—Both immunosuppressive protocols were effective in reducing progression of AF. Subsequent draining tracts excision, cryptectomy, and anal sacculectomy were bilateral (12 dogs) or unilateral (13 dogs of which 4 had bilateral anal sacculectomy). Postoperative recovery was uneventful, except for 2 dogs that had wound breakdown. Recurrence was not observed in any of the dogs that had bilateral surgical excision and or in 9 dogs that had unilateral excision.Conclusion—Preoperative immunosuppressive therapy, combined with bilateral surgical resection of affected tissue consistently, resulted in resolution of AF. Four dogs that had recurrence had unilateral excision despite initial bilateral involvement, suggesting that all diseased tissue should be excised.Clinical Relevance—These preliminary results suggest that immunosuppressive therapy before surgical excision for AF yields minimizes recurrence in dogs.