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At least 1,153 records · Page 64Linked to original sources
PubMed1989

Comparison of hypoxia and ouabain effects on the myocardial uptake kinetics of technetium-99m hexakis 2-methoxyisobutyl isonitrile and thallium-201.

Effects of hypoxia and ouabain on transcapillary exchange of [99mTc]hexakis (2-methoxyisobutylisonitrile) [SESTAMIBI, also known as MIBI or HEXAMIBI] and 201TI were investigated with indicator-dilution studies using isolated rabbit hearts. Peak myocardial extraction (Emax), permeability-surface area products (PScap), and net myocardial extraction (Enet) were compared among serial injections during constant coronary flows. Overall, measures of transcapillary transport (Emax and PScap) for SESTAMIBI were significantly lower (p less than 0.001) than those simultaneously determined for thallium, but estimates of tissue retention (Enet) for SESTAMIBI and thallium were not statistically distinguishable. Hypoxia had no significant effect on mean (+/- s.d.) Emax for SESTAMIBI (0.31 +/- 0.13) or thallium (0.59 +/- 0.11), nor on mean PScap or Enet values. Ouabain (1.5 X 10(-7) M and 1.5 X 10(-6) M) had no effect on SESTAMIBI or thallium Emax (respectively, 0.29 +/- 0.08 and 0.60 +/- 0.05) or on PScap for SESTAMIBI. Thallium PScap was depressed with higher ouabain dose (control, 1.22 +/- 0.40; high ouabain, 1.06 +/- 0.41 ml/min/g; p less than 0.01). Ouabain also caused a significant and progressive increase in average SESTAMIBI Enet (control, 0.23 +/- 0.10 to high ouabain, 0.33 +/- 0.12; p less than 0.05), but depressed thallium Enet (control, 0.38 +/- 0.14 to high ouabain, 0.32 +/- 0.18; p less than 0.01). These results suggest myocardial metabolic and/or functional status have minor influence on transcapillary transport of SESTAMIBI and thallium, but significantly affects cellular retention.

Animals↗
PubMed1987

The postnatal development of the dopamine-containing innervation of dorsal and ventral striatum: effects of the weaver gene.

We report here that the pattern of loss of dopamine that occurs in the brains of adult mice carrying the autosomal recessive weaver gene is the consequence both of failed postnatal development of the dopamine-containing mesostriatal innervation and of the disappearance of the early forming dopamine-island system. For these studies, we compared the contents of dopamine extracted from 3 divisions of the striatum, the caudoputamen, nucleus accumbens, and olfactory tubercle, and from the midbrain of weaver and control littermate pups. Catecholamines were extracted from tissues dissected from serial brain slices and were separated and measured using high-performance liquid chromatography followed by electrochemical detection. The anatomical pattern formed by the catecholamine-containing innervation of the developing striatum was studied in 8-, 11-, 20-d-old, and 1.5-month-old weaver and control mice using tyrosine hydroxylase immunohistochemistry. In weaver neonates (7-8 d old), the dopamine-containing innervation of the caudoputamen is characterized by near-normal concentrations of dopamine and by a normal anatomical arrangement of dopamine islands. Subsequently, however, the weaver disease is expressed in the caudoputamen as a failure of the dopamine islands to persist and of the dopamine-containing innervation of the matrix to develop at a normal rate. Whereas the concentration of dopamine increases 4.4-fold between days 7 and 33 in normal animals, it increases only 1.6-fold in the weaver. In spite of the severe reduction of dopamine, the weaver's caudoputamen grows to near-normal size (85%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Further characterization of the leukemogenic activity of haloperidol in mice.

Haloperidol, a butyrophenon, is widely used for the treatment of psychotic disorders in man. Recently we reported that this drug causes, with high incidence, the development of monocytic-myeloid leukemias in male NMRI mice upon 5 X 5 mg/kg i.p. administration. Here we present evidence for the leukemogenic effect of haloperidol in two other strains of mice (XVII AKF1 hybrids, and the low leukemic BALB/c/BOM). The strain-dependent incidence of leukemias ranged both in males and females between 34% (AKR) and 69% (XVII AKF1) with average latencies between approximately 200 (AKR) and 600 (BALB/c) days. On the basis of cytological and cytochemical criteria the predominating type of leukemias was classified as monocytic-myeloid. These leukemic were serially transplantable. Cell-free extracts of leukemic tissues did not induce the disease indicating that no virus was activated by haloperidol. However, when the drug was administered to AKR mice after a suboptimal dose of nitrosomethylurea (NMU), a higher incidence of mixed-type leukemias was observed as with haloperidol alone. NMU alone induced lymphatic leukemias with proven viral involvement. The tumor promoter 12-0-tetradecanoylphorbol-13-acetate did not influence haloperidol-induced leukemogenesis.

Animals↗
PubMedDate not supplied

[Host range of drosophila melanogaster C virus among diptera and lepidoptera (author's transl)].

The host range of the C picornavirus of Drosophila melanogaster was studied, using numerous strains of Drosophila together with four other genera of diptera and two species of lepidoptera. C virus was injected into the different hosts and serially passaged in them. The extracts from each passage were biologically assayed on virus free D. melanogaster. Four different situations were found. 1) A high level of multiplication leading, in 45 strains of Drosophilidae, to the early death of the hosts. This phenomenon was particularly related to the subgroup melanogaster and in the dipteron Ceratitis capitata. The titre of the virus in this latter insect was high as in D. melanogaster, but its cellular tropism was wider. 2) An active viral multiplication but without symptoms, in two strains of D. immigrans and in the lepidopteron Galleria mellonella. In these two insects, the viral titre was clearly inferior to that observed in D. melanogaster. 3) Maintenance of the virus, without multiplication in the dipteron Calliphora erythrocephala and the lepidopteron Arctia caja. In these insects, the decrease in virus titre was directly related to the dilution factor at each passage. 4) Rapid disappearance of the virus, in the mosquitoes Culex pipiens and Aedes aegypti. The host range of C virus is compared to that of Sigma virus of Drosophila and of two other picornaviruses of insects.

Animals↗
PubMed2006

Developmental occlusion, orthodontic interventions, and orthognathic surgery for adolescents.

This article addresses issues in orthodontics such as timing of treatment, expansion in the absence of a posterior crossbite, serial ex-tractions, treatment of Class II and III malocclusions, treatment of open bites, extraction versus nonextraction, preservation of E-space to resolve crowding, orthodontics and temporomandibular disorders, orthognathic surgery, and current trends in orthodontics. Although much information is presented on these topics, many controversies still exist. When more data from evidence-based systematic reviews become available, more predictable and standardized orthodontic treatments may develop.

Adolescent↗
PubMed2003

Antifungal effects of different organic extracts from Melia azedarach L. on phytopathogenic fungi and their isolated active components.

Extracts from different parts of Melia azedarach L. were studied as potential antifungal agents for selected phytopathogenic fungi. In a serial agar dilution method, hexanic and ethanolic extracts from fruit, seed kernels, and senescent leaves exhibited fungistatic activity against Aspergillus flavus,Diaporthe phaseolorum var. meridionales, Fusarium oxysporum, Fusarium solani, Fusarium verticillioides, and Sclerotinia sclerotiorum. Both hexanic extract from senescent leaves and ethanolic extract from seed kernel were highly effective on all tested fungi, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 25 mg/mL and 0.5 to 5 mg/mL, respectively. In addition, all of the above-mentioned extracts showed fungicidal activity on these fungi, with ethanolic seed kernel extract being the most active. Three compounds displaying activity against F. verticillioides were isolated from the ethanolic seed kernel extract and were characterized as vanillin (1), 4-hydroxy-3-methoxycinnamaldehyde (2), and (+/-)-pinoresinol (3), with MICs of 0.6, 0.4, and 1.0 mg/mL, respectively. These compounds also showed a synergistic effect when combined in different concentrations, needing four times less concentration to reach complete inhibition in the growth of F. verticillioides.

Antifungal Agents↗
PubMed1966

Serological studies of parasitized cattle. I. Complement--fixing activity of serial serum samples.

Complement-fixation (CF) tests with sonicated aqueous extracts of adult forms of five species of gastrointestinal nematodes as antigens have been made on serial biweekly bleedings from two groups of parasitized calves grazing on infected pastures during the 1963 or 1964 seasons. Three of these nematode species, Cooperia oncophora, Ostertagia ostertagi and Nematodirus helvetianus, were found in large numbers in most of these animals. The calves were negative serologically before being placed on pasture but within 2 to 4 weeks some had developed considerable CF activity with Cooperia and other nematode antigens. Ten calves died, however, before significant CF titres had been attained. Eight control calves in the 1963 or 1964 groups which were grazed on "clean" pastures, remained serologically negative during the summer and autumn months. Four of the six surviving exposed animals in the 1964 group showed a fall in CF activity during the winter months when they were stabled, whereas the six surviving controls developed low CF titres suggesting that they were becoming mildly parasitized. In the spring of 1965 CF titres began to rise in some of the previously exposed and control yearlings even before they were placed on infected pasture in June.

Animals↗
PubMed1979

Evidence favoring the existence of two high molecular weight precursor forms of dog kidney renin.

Extraction of canine renal cortical tissue at pH 7.4 in the presence of the protease inhibitors diisopropylfluorophosphate (0.2 mM), Na2EDTA (7.8 mM), sodium tetrathionate (7.8 mM). N-ethyl maleimide (7.8 mM) yielded renin activity in two high molecular weight (HMW) forms, 65,000 (65K) and 55,000 (55K). Serial gel filtration chromatography of such extracts stored at 4 C showed that over the course of 2 days, activity at both 65,000 and 55,000 decreased almost entirely, while low molecular weight (LMW) activity at 41,000 (41K), not present immediately after extraction, had appeared in the extracts, The renin activity of the extract doubled over the first 24 h of storage and remained stable over the next 24 h. The activity of all three renin forms was comparably inhibited by antirenin antibodies. Our results support the concept that HMW renin(s) is a biological precursor of 41K renin. The new finding of a renin form intermediate in apparent molecular weight between 65K and 41K renin suggests that proteolytic processing of HMW to LMW renin may involve more than one step. The fact that in vitro conversion of HMW to LMW renin will occur under these conditions but takes place slowly may provide a technique for the future study of the precise manner in which HMW is converted to LMW renin.

Animals↗
PubMed1983

Serial observations on the pathophysiology of acute stroke. The transition from ischaemia to infarction as reflected in regional oxygen extraction.

Regional cerebral blood flow, fractional oxygen extraction and oxygen metabolism have been measured in 34 patients after acute nonhaemorrhagic cerebral hemispheric infarction. Nine cases showed elevated oxygen extraction in the region of the early infarct, and these were the patients studied earliest after the onset of stroke. The results of serial studies to follow the evolution of the pathophysiology of acute stroke in these 9 patients are presented. The elevated oxygen extraction within the early infarct showed a significant reduction over the week following the onset of stroke. The reason for this fall in the fractional use of available oxygen varied in individual cases, and at the extremes was associated with a marked reduction in oxygen metabolism with a further small fall in residual blood flow, or a return of flow without recovery of oxygen metabolism. The significance of oxygen extraction in terms of potential viability of the tissue is discussed. The finding of a lower oxygen extraction in subcortical grey and white matter compared to cortex within the first hours or days of a major stroke is considered indicative of an earlier change from ischaemia to infarction in the deep tissues, probably related to the anatomy of the microvasculature. The interpretation of the results in the light of knowledge accumulated from studies of ischaemia in animals is presented, and problems imposed on data analysis by current limitations in positron emission tomography are discussed.

Adult↗
PubMed2000

Rapid three-dimensional segmentation of the carotid bifurcation from serial MR images.

The current trend in computational hemodynamics is to employ realistic models derived from ex vivo or in vivo imaging. Such studies typically produce a series of images from which the lumen boundaries must first be individually extracted (i.e., two-dimensional segmentation), and then serially reconstructed to produce the three-dimensional lumen surface geometry. In this paper, we present a rapid three-dimensional segmentation technique that combines these two steps, based on the idea of an expanding virtual balloon. This three-dimensional technique is demonstrated in application to finite element meshing and CFD modeling of flow in the carotid bifurcation of a normal volunteer imaged with black blood MRI. Wall shear stress patterns computed using a mesh generated with the three-dimensional technique agree well with those computed using a mesh generated from conventional two-dimensional segmentation and serial reconstruction. In addition to reducing the time required to extract the lumen surface from hours to minutes, our approach is easy to learn and use and requires minimal user intervention, which can potentially increase the accuracy and precision of quantitative and longitudinal studies of hemodynamics and vascular disease.

Carotid Arteries↗
PubMed1993

Prenatal sex determination from maternal peripheral blood using the polymerase chain reaction.

We have investigated the use of a nested polymerase chain reaction assay for the detection of a fetal-specific Y-chromosomal sequence (DYS14) from DNA extracted from unsorted maternal peripheral blood. Serial dilutions of male DNA into female cord blood DNA indicated that the assay could detect an equivalent of a single male cell in 300,000 female cells. The assay exhibited absolute specificity for male DNA with no amplification from a DNA panel obtained from 10 female cord blood samples. When used on DNA extracted from unsorted peripheral blood from a series of pregnant women, the predictive values of a positive test for a male fetus were 86%, 67% and 87% in the first, second and third trimesters, respectively. We have also demonstrated that retesting the samples allows the detection of a proportion of male-bearing pregnancies with a high degree of accuracy, in that all 15 women who gave positive signals in two consecutive amplifications had male fetuses. We have also applied the test at 8 weeks postpartum to eight women who had previously delivered male babies; no Y-specific signal could be detected in any of them, suggesting that most women have cleared their circulation of fetal cells by 8 weeks after parturition.

Base Sequence↗
PubMed1983

Salivary gland glucagon is a fictitious substance due to tracer-degrading activity resistant to protease inhibitors.

A high level of glucagon immunoreactivity was apparently detected in acid-saline extract from rat submandibular glands, but tracer glucagon added to the assay mixture was mostly damaged in spite of the presence of protease inhibitors commonly used in radioimmunoassay. Gel-filtration of the extract on a Bio-Gel P-10 column revealed strong tracer-degrading activity at the void fraction where the apparent immunoreactivity was eluted. Serial changes in apparent immunoreactivity of the extract fit well on the theoretical curve of an exponential tracer degradation. These findings indicate that the salivary gland glucagon is a fictitious substance due to tracer degradation during radioimmunoassay. Further study revealed that the glucagon molecule was hydrolyzed at the arginyl bonds and split into two fragments during incubation with the acid-saline extract from rat submandibular glands.

Animals↗
PubMedDate not supplied

Growth of normal oral keratinocytes and squamous cell carcinoma cells in a novel protein-free defined medium.

A novel protein-free synthetic medium was developed for the culture of normal human oral keratinocytes. This medium, designated PFM-7, supports the serial cultivation of primary or secondary normal oral keratinocytes in protein-free, chemically defined conditions. Normal oral keratinocytes in PFM-7 exhibited nearly equal growth in mass culture without noticeable changes in morphology, response to added growth factors, or gene expression of growth factors and their receptors, compared to cells in Keratinocyte-SFM containing epidermal growth factor and bovine pituitary extract. Furthermore, PFM-7 supported the serial subcultivation of human squamous cell carcinoma cells and enabled both normal and malignant oral squamous cells derived from the same patient to grow under the same protein-free defined conditions. These results indicate that PFM-7 can be used for precise investigations of growth mechanisms, cell products, and gene expression associated with carcinogenesis of human epidermal cells.

Animals↗
PubMed1984

Structure and genetic complexity of the genomes of herpesvirus defective-interfering particles associated with oncogenic transformation and persistent infection.

The complexity and structural organization of defective-interfering (DI) particle DNA of equine herpesvirus type 1 (EHV-1) have been elucidated by using restriction enzyme and Southern blot hybridization analyses. DI particles were generated by serial high-multiplicity passage of EHV-1 in L-M cells, and total viral DNA was extracted from virus purified from supernatants of these serial passages. EHV-1 DI particle DNA was quantitatively separated from standard (STD) DNA by several cycles of CsCl isopycnic banding in a vertical rotor. Restriction endonuclease digestion profiles of pure DI DNA were completely different from the mapped patterns observed for EHV-1 STD DNA. Digestion of pure defective DNA with restriction enzymes (Bg/II, EcoRI, and XbaI), for which there are few or no cleavage sites within the S (short) region of the EHV-1 STD genome, yielded high-molecular-weight supermolar DNA bands, suggesting that a large subgenomic repeat unit was present in defective DNA. DNA blot hybridization analysis with the Bg/II supermolar fragment of defective DNA, intact DI particle genomic DNA, and EHV-1 STD DNA restriction enzyme fragments as 32P-labeled probes indicated that the EHV-1 DI particle genome originates predominately from the STD DNA S region (0.77 to 1.00 map units) and to a lesser extent from the left terminus of the unique long (UL) region (0.00 to 0.05 map units). None of the EHV-1 DNA sequences associated to date with EHV-1 oncogenesis (0.32 to 0.38 map units; O'Callaghan et al. in B. Roizman [ed.], Herpesviruses, in press; Robinson et al., Cell 32:204-219, 1983, and Proc. Natl. Acad. Sci., U.S.A., 78:6684-6688, 1981) were detected in the DI particle DNA. The importance of these data with regard to DNA replication of DI particles and the role of DI particles in one model system of EHV-1 oncogenic transformation are discussed.

Animals↗
PubMed1992

Detection of hepatitis "C" virus in formalin-fixed liver tissue by nested polymerase chain reaction.

Interpretation of antibody to hepatitis C virus (HCV) in patients with liver disease is difficult due to false-positive reactivity in some conditions. To evaluate the feasibility of HCV in archival material, HCV was sought in formalin-fixed, paraffin-embedded liver biopsy specimens. Nested polymerase chain reaction was used to detect hepatitis C virus in formalin-fixed, paraffin-embedded liver biopsy specimens after total RNA was extracted from tissue by proteinase K digestion and phenol/chloroform purification. The relative efficiency of amplification of HCV RNA from formalin-fixed material was estimated semiquantitatively by serial dilution of cDNA synthesised from RNA extracted from fresh and formalin-fixed sections from the same liver. Although HCV RNA could be detected in formalin-fixed liver tissue by nested PCR in 5/5 cases in which HCV was detected in serum, amplification was approximately 5-fold less efficient than when HCV was amplified from fresh tissue. Nevertheless, nested PCR of HCV from formalin-fixed liver tissue represents a useful technique in addressing some important questions related to the pathogenesis of liver disease.

Adult↗
PubMed2002

Treatment of transtentorial herniation unresponsive to hyperventilation using hypertonic saline in dogs: effect on cerebral blood flow and metabolism.

We tested the hypothesis that transtentorial herniation (TTH) represents a state of cerebral ischemia that can be reversed by hypertonic saline. Because of the high mortality associated with TTH, new therapeutic strategies need to be developed for rapid and effective reversal of this process. We produced TTH (defined by acute dilatation of one or both pupils) by creating supratentorial intracerebral hemorrhage with autologous blood injection in seven mongrel dogs anesthetized using intravenous pentobarbital and fentanyl. We measured serial rCBF (regional cerebral blood flow) using radiolabeled microspheres in regions around and distant to the hematoma. Cerebral oxygen extraction and oxygen consumption (CMRO2) were measured by serial sampling of cerebral venous blood from the sagittal sinus. Mean arterial pressure (MAP) and intracranial pressure (ICP) were continuously monitored. TTH was successfully reversed over a mean period of 25.7 +/- 4.9 minutes after intravenous administration of 23.4% sodium chloride (1.4 mL/kg) in all animals. All measurements were recorded 15, 30, 60, and 90 minutes after administration of 23.4% sodium chloride. Compared to prehematoma ICP (14.1 +/- 1.7 mm Hg, mean +/- SE), elevation in ICP was observed during TTH (36.2 +/- 7.2 mm Hg) with no change in cerebral perfusion pressure (CPP) (80.4 +/- 4.7 vs. 76.7 +/- 10.1 mm Hg) because of concomitant elevation in mean arterial pressure. Compared to baseline values, there was a reduction in rCBF (mL/100 gm/min +/- SE) in brainstem (12.1 +/- 2.0 vs. 21.4 +/- 1.4), gray matter (18.2 +/- 2.1 vs. 31.4 +/- 1.8), and white matter (8.6 +/- 1.7 vs.18.7 +/- 0.9) in the hemisphere contralateral to the hematoma; and gray matter (12.9 +/- 2.9 vs. 27.9 +/- 2.2) and white matter (8.3 +/- 2.0 vs.19.9 +/- 1.0) in the ipsilateral hemisphere distant from the hematoma. Administration of 23.4% sodium chloride resulted in reduced ICP at 15 minutes (12.7 +/- 1.4) and 30 minutes (15.6 +/- 3.1) after administration. RCBF values were restored in all regions studied after administration of 23.4% sodium chloride with an increase in CMRO2 (1.8 +/- 0.4 vs. 3.9 +/- 0.7 mL O2 /100 gm/min). Compared with baseline values, rCBF increased in the ipsilateral (31.7 +/- 2.5 vs. 63.4 +/- 11.7) and contralateral (28.7 +/- 1.9 vs. 45.5 +/- 5.7) thalamus at 15 minutes after administration of 23.4% sodium chloride. TTH represented a state of ischemia in brainstem and supratentorial gray and white matter in the presence of adequate CPP, suggesting mechanical compression of vessels at the level of tentorium. Hypertonic saline reversed TTH, and restored both rCBF and CMRO2, although hyperemia was observed immediately after reversal of TTH. Administration of hypertonic saline may preserve neurologic function during the interim period between TTH and surgical intervention.

Animals↗
PubMed2003

Biological and histopathological studies of some plant extracts on larvae of Culex pipiens (Diptera: Culicidae).

The water extract of Artemisia monosperma, Eichhornia crassipes and Zygophyllum coccineum was tested against the 2nd instar larvae of Culex pipiens and the resulting pupae and adults. The larvae were exposed to serial concentrations (0.5, 1.0 and 2.0%). All extracts showed marked effects on larval mortality, pupation and adult emergence as compared to the non-treated group. These effects were dose (concentration) dependant (P < 0.001). The results indicate that the water extract of E. crassipes gave marked and significant effects, followed by A. monosperma and Z. coccineum particularly at 2% concentration (P < 0.001). The water extract of E. crassipes at 2% conc. revealed drastic effect on larval midgut, integument, fats and muscles. These histopathological effects increased with increasing the time of exposure (treatment).

Aging↗
PubMed2003

Anchorage loss--a multifactorial response.

Anchorage loss (AL) is a potential side effect of orthodontic mechanotherapy. In the present study, it is defined as the amount of mesial movement of the upper first permanent molar during premolar extraction space closure. In addition, AL is described as a multifactorial response in relation to the extraction site, appliance type, age, crowding, and overjet. For this study, 87 university clinic and private practice subjects, who were defined as maximum anchorage cases and had undergone bilateral maxillary premolar extractions, were divided into four groups according to extraction site (first vs second premolars), mechanics (lingual vs labial edgewise appliances), and age (adolescents vs adults). Overjet and crowding were examined from the overall sample. Data were collected from serial lateral cephalograms and dental casts. The results showed that as the severity of dental crowding increased, AL significantly decreased (r = -0.66, P = .001). Labial edgewise appliances demonstrated a significantly greater AL than did lingual edgewise appliances (1.15 +/- 2.06 mm, P < .05). A greater, though not statistically significant, AL was found in adults than in adolescents (0.73 +/- 1.43 mm). There was a slight nonsignificant increase in AL between maxillary second compared with first premolar extractions (0.51 +/- 1.33 mm). Overjet was weakly correlated to AL. These results suggest that AL is a multifactorial response and that the five examined factors can be divided into primary (crowding, mechanics) and secondary factors (age, extraction site, overjet), in declining order of importance.

Adolescent↗