Activity of lysosomal acid phosphatase in leukocytes of rats chronically intoxicated with benzene vapors

In rats chronically exposed to benzene vapours of 1200 mg/m3 concentration, 6 hr daily, 6 days a week, during 12 weeks, acid phosphatase activity (AcP) was evaluated in neutrophils and lymphocytes of peripheral blood. One found an increase in AcP activity in neutrophils, correlating with duration of exposure, lymphocytopenia, correlating with duration of exposure, and increase in AcP--positive lymphocytes percentage, mainly with cytoplasmic and lysosomocytoplasmic localization of enzyme. Besides distant effects of chronic benzene intoxication were evaluated, 5 months after the exposure had been intermitted. Normal AcP activity in neutrophils, lymphocytopenia, and increase in AcP--positive lymphocytes percentage were found with cytoplasmic and lysosomo-cytoplasmic localization of enzyme. The authors suggest a possibility of using the changes observed in lymphocytes, on a subcellular level, to evaluate distant effects of occupational exposure to benzene.     

Effect of dietary magnesium level on nephrocalcinosis and growth in rats

We studied the extent of kidney calcification by varying dietary levels of Mg, based on pathological examinations and calcium (Ca) and magnesium (Mg) balance tests. AIN-76 diets containing varying levels of Mg--0.3 (-M), 1.3 (1/20M), 2.4 (1/10M), 9.2 (1/5M), 19 (control), 38 (2M), 102 (5M), and 187 (10M) mmol/kg diet--were fed to 3-week-old male Fischer-344 rats for 14d. Although the magnitude of abnormality was highest in kidney of rats fed the -M diet, the damage was normalized as the dietary level of Mg increased, with increasing serum Mg concentration and urinary excretion of Mg. We found almost no deposition of Ca in rats fed the 10M diet. The mechanism by which the high dietary Mg induces these effects most likely involves a competition between Mg and Ca for reabsorption in proximal and/or distal tubules, since these diets increased the urinary excretion of Ca. However, these high Mg diets decreased food intake and body weight gain compared with the control diet, although these indices were not decreased in rats fed the 2M diet. The results suggest that a dietary magnesium level approximately twice the normal level effectively reduces kidney calcification while maintaining normal growth in rats.     

Effect of maxillary edentulousness on mandibular residual ridges

Bone mineral density (BMD) was measured in five different regions of the mandible of 77 postmenopausal women. These women were also classified according to the remaining, clinically determined alveolar height in the edentulous distal regions of the mandible. The duration of edentulousness in the maxilla and in the mandible was determined anamnestically. All subjects were edentulous in the maxilla, and 42 were also edentulous in the mandible. The other 35 women had teeth only in region d35-d45. This study shows that after extraction of the last teeth in the mandible, the BMD of the cortical bone is not lowered, but that the BMD of the trabecular portion is lowered more by mechanical stress caused by the remaining natural teeth than by maxillary dentures. This feature becomes apparent when duration of edentulousness in the maxilla is compared with the BMD values of different regions in the mandible.     

Growth of mandibular prognathism after pubertal growth peak

Until recently, the signal transduction pathways involved in the processes of tumor growth have been poorly understood. In the present study, we investigated cell surface receptors which utilize phosphatidylinositol (Pl) turnover/Ca2+ mobilization as a signal transduction pathway to regulate cell growth in a metastatic human lung carcinoma cell line, PG. We found that purinoceptor agonists, including ATP and its analogs, and bombesin, an amphibian tetradeca-peptide of mammalian homology gastrin-releasing peptide, induced rapid transient increase of cytoplasmic-free Ca2+ in PG cells loaded with fura-2. The Ca2+ responses were derived both from release from internal stores and the opening of plasma membrane Ca2+ channels. HPLC analysis of inositol 1,4,5-triphosphate (Ins(1,4,5)P3) and its isomers showed a receptor-linked phospholipase C activation by ATP and bombesin. Although ATP and bombesin were both able to induce Pl turnover and Ca2+ mobilization in PG cells, they had differential growth regulatory effects on PG cells. Treatment with bombesin stimulated PG cell growth while treatment with ATP inhibited significantly PG cell growth. Pharmacological studies showed that the purinoceptors on PG cells were of the P2 subtype. Other hydrolysis-resistant P2 purinoceptor agonists, including ATP gamma S and AMP-PNP, were as effective as ATP in stimulating Pl turnover and Ca2+ mobilization as well as in inhibiting PG cell growth in vitro, suggesting the potential usefulness of such ATP analogs in clinical trials. Preliminary results suggest G protein involvement in the differential regulation of ATP and bombesin signal transduction pathways.     

Effect of clenbuterol on growth and body composition during food restriction in rats

Clenbuterol was administered as a dietary admixture (4 mg/kg diet) to three groups of male Wistar rats (n = 8) housed individually in metabolism cages and fed for 15 d at 110, 160, and 235% (ad libitum) of estimated requirement for energy maintenance. Untreated groups at each level of energy intake were also included. There was no effect of clenbuterol on food intake in the ad libitum group, but the drug produced significant increases in body weight, feed efficiency, and carcass weight, dressing and protein content at all three levels of energy intake. This effect of clenbuterol was particularly noticeable in the restricted animals. Clenbuterol caused changes in body composition (increased percentage of water and protein, decreased percentage of fat) in the ad libitum rats but had no effect in the restricted groups. The reduction in the growth of the viscera caused by energy restriction was not affected by clenbuterol, apart from in the 110% restricted group, where the gastrointestinal tract was 26% heavier in the clenbuterol-treated rats. The results show that the growth anabolic actions of clenbuterol can be sustained and may be even more marked in rats fed restrictively than in those given ad libitum access to feed.     

不同类型黄铁矿对微生物浸铀行为的影响

针对低硫铀矿生物浸出,采用外源添加黄铁矿强化微生物浸铀,开展三种不同类型黄铁矿对微生物浸铀的影响研究。结果表明:添加黄铁矿可有效降低浸出体系pH,为微生物提供相对良好的浸出环境;添加黄铁矿促进体系内Fe2+快速氧化和氧化还原电位值迅速升高;黄铁矿体系与未添加黄铁矿空白体系相比,铀浸出率提高1.73%～5.53%;添加黄铁矿可降低微区黄钾铁矾等沉淀形成。     

The effect of deformation on abnormal grain growth in tungsten ingots

This paper reports a study of abnormal grain growth in tungsten ingots that had been deformed in compression at elevated temperatures. The results show that very large grains form in these samples directly from the polygonized structure when the deformed samples are annealed. A critical amount of deformation is required to begin this process. Beyond that point, the resulting grain size decreases with increasing amounts of deformation and decreasing test temperature. Abnormal grain growth occurs first in the regions of the sample that have undergone the most strain. Two factors appear to provide the driving force for the formation of these large grains. One is the elimination of grain boundary area. This effect would be present in any system undergoing regular or abnormal grain growth. The other is the elimination of grains that are more highly strained by grains that are less strained. In this way, this process is similar to the large grain growth resulting from strain annealing.     

Effect of hepatocyte growth factor on the proliferation of intrasplenically transplanted hepatocytes in rats

Expression of genes encoding insulin-like growth factor I (IGF-I), insulin-like growth factor II (IGF-II) and type I insulin-like growth factor receptor (IGFr) was measured in theca and granulosa cells from the ovary of the laying hen, using an RNase protection assay. Expression of genes encoding IGF-I and -II was confined to theca tissue and expression was not detected in granulosa cells. In contrast, expression of genes encoding IGFr in granulosa cells was significantly greater than that in theca tissue. The 98 base IGF-II probe was similar to a region of the second coding exon of chicken IGF-II and produced multiple RNase-protected RNA hybrids. Theca RNA from follicles at all stages of development produced RNase-protected hybrids of size 98, 96 and 90 bases; however, an additional band (66 bases) was also observed in theca RNA from small yellow follicles. The stage of follicular development during which maximum amounts of the 66 base RNase-protected fragment was detected correlates with the stage at which small follicles are selected for recruitment into the follicular hierarchy. The results provide evidence for the involvement of IGFs in the intraovarian control of ovarian function in a non-mammalian species, and highlight the importance of IGF-II in this process.     

Effect of oxygen content on the structural characteristics of uranium oxycarbides

Conclusions A study was made of the effect of oxygen content upon the structural characteristics of uranium oxycarbides. It is shown that uranium oxycarbides are deficient phases with an ordered disposition of vacancies. The fact that, with rise in the oxygen content of the oxycarbide, the number of vacant sites in both the sublattices increases and the crystal lattice parameter decreases is explained in terms of the occurrence of Me-Me and Me-X reactions.Translated from Poroshkovaya Metallurgiya, No. 9 (141), pp. 91–94, September, 1974.     

The effect of small deformation on abnormal grain growth in bulk Cu

The effect of small deformation below the level (about 8 pct) required for primary recrystallization on abnormal grain growth (secondary recrystallization) has been investigated in bulk polycrystalline Cu. The starting microstructure, without any texture and with a nearly uniform grain size of 168 μm, has been obtained by compressing a cylindrical Cu specimen and recrystallizing at 800 °C. The fully recrystallized specimen shows distinct abnormal grain growth (AGG) after heat treatment at 800 °C for 12 hours. Most of the grain boundaries are faceted when observed under transmission electron microscopy (TEM), and most of the faceted segments are expected to be singular. A singular grain boundary free of defects will migrate by two-dimensional nucleation of new layers, with its velocity varying nonlinearly with the driving force arising from the grain-size difference. Such a growth mechanism is analogous to the well known process for the growth of crystals with singular surfaces from liquid or vapor. The grains slightly larger than the average size will hardly grow, because the driving force for their growth is not sufficient for nucleation of new crystal layers at the boundaries. Those grains larger than a certain critical size will, however, grow at ever-increasing rates with their increasing size, because of the sufficient driving force for two-dimensional nucleation. Such a selective accelerated growth of large grains results in overall AGG behavior. The specimen deformed to 2 pct shows AGG after heat treatment for only 5 minutes at 800 °C, and after 1 hour, large impinged grains are obtained. The grain boundaries show many extrinsic dislocations even after the heat treatments. As proposed earlier by Gleiter, Balluffi, Smith, and their colleagues, the extrinsic grain-boundary dislocations increase the grain-boundary mobilities even at low driving forces, and, hence, even those grains slightly larger than the average size can rapidly grow at the early stages of the heat treatment, in agreement with the observation. In the specimens deformed to 4 to 8 pct, below the level for primary recrystallization, all grains grow steadily without producing distinct AGG. With high densities of extrinsic dislocations at the grain boundaries even after long heat treatments, all grains can readily grow, resulting in overall growth patterns resembling the normal growth. When deformed to 20 and 50 pct, primary recrystallization occurs, and the subsequent AGG behavior depends on the grain size obtained at the completion of the primary recrystallization. Similar small-deformation effects are observed with heat treatment at 600 °C.     

Effect upon longitudinal growth of femur by intramedullary nailing in rats

In an experimental study using rats it was found that intramedullary nailing through the distal femoral growth plate resulted in a significant retardation of longitudinal growth. Drilling only and pin removal after 7 weeks also gave significant inhibition of growth after 14 weeks, while drilling only with immediate removal of the pin gave no growth disturbance during the first 7 weeks. The investigation indicates that damage to the central portion of the epiphyseal growth plate in rats leads to inhibition of longitudinal growth.     

Effect of growth hormone treatment on the healing of left colonic anastomoses in protein-malnourished rats

BACKGROUND: Malnutrition is known to affect wound healing but it is not known with certainty whether or not postoperative hyperalimentation can reverse this defect. The present study was designed to examine the effects of recombinant human growth hormone (hGH) on left colonic anastomoses in malnourished rats. METHODS: Experimental animals were allocated randomly into four groups. In groups 1 and 2 animals were fed with normal diet for 10 days before surgery. In groups 3 and 4 animals were fed with a low-protein diet. Left colonic anastomoses were performed in all animals. Following surgery, rats in groups 1 and 3 received hGH whereas rats in groups 2 and 4 were injected with saline as control. Bursting pressure and hydroxyproline levels on day 4 after operation were used to determine anastomotic healing. Results: Bursting pressure was lower in the malnourished rats than those fed with normal diet (P< 0.05). Bursting pressure was higher in normally fed rats which were given hGH. No significant differences could be noted between malnourished control rats and those receiving hGH. CONCLUSION: These results suggest that hGH strengthened the left colonic anastomoses in rats fed a normal diet, but could not reverse the negative effects of malnutrition on colonic anastomoses.     

Condylar condition and mandibular growth during early functional treatment of children with juvenile chronic arthritis

TMJ involvement in children with Juvenile Chronic Arthritis (JCA) will frequently cause disturbance of the growth of the mandible. Orthodontic treatment of these patients often includes orthognathic surgery, and are complicated to handle with respect to the damaged joint and impaired function. The aim of this presentation is to suggest an early treatment with a functional splint appliance, a distraction splint, with the purpose of increasing function of the joint and ensuring continuous growth of the mandible.     

Pattern and process of growth of the abnormal human fetus

Identifying patterns of fetal growth alteration benefits both the clinician and the researcher. Twenty-four measurements in three variable sets (anthropometric measures, organ weights, and long-bone measures from radiographs) were taken on fetuses both with and without pathological conditions that are suspected to result in growth alteration. In addition, radiographs of each case were examined for the presence or absence of ossification centers. Based on least-squares regressions of the normal group, we calculated standardized residuals for the affected group to identify patterns of growth alteration. A large sample of fetuses between 15 and 42 weeks of gestational age with a variety of pathological conditions is described and evaluated for growth alterations. Symmetric and asymmetric growth alteration was detected in a small part of the sample and was predominantly isolated to fetuses in the late third trimester. Although patterns of growth alteration have been suggested as a means for noninvasive diagnoses of syndromes (such as trisomy 21), no consistent patterns are discernible in the current group. The sample provides a unique opportunity to evaluate fetal growth in terms of the interaction between genetic and environmental influences.     

Effects of cardiomyoplasty on cardiac growth in rats

BACKGROUND AND AIM OF THE STUDY: Cardiomyoplasty (CMP) has been proposed as a treatment for pediatric patients, but restriction of cardiac growth by the muscle wrap is a potential source of concern. This possibility was investigated in an immature animal model. METHODS: Six-week-old rats (body weight 203.8 +/- 5.4 g, mean +/- SEM) underwent either left thoracotomy with CMP (group I, n = 7), or thoracotomy without CMP (group II, n = 8). A third group (group III, n = 7) served as untreated controls. Final measurements were made 20 weeks later after body weights had reached a plateau. RESULTS: Preoperative body weights were not significantly different between the groups. At elective sacrifice, the body weights of animals that underwent surgery did not differ significantly (group I, 558.0 +/- 21.5 g and group II, 617.3 +/- 20.3 g), but were significantly less than those of control animals (727.6 +/- 13.3 g, p < 0.001 and p < 0.01, respectively). Cardiac ventricular weights in the CMP group were significantly less than those of control animals (group I, 1.21 +/- 0.06 g; group III 1.45 +/- 0.04 g; p < 0.01), but were not statistically different from those of the sham thoracotomy group (group II, 1.36 +/- 0.05 g). Mean left ventricular end-diastolic volumes were similar in all groups (group I, 0.67 +/- 0.07 mL; group II, 0.66 +/- 0.07 mL; and group III, 0.69 +/- 0.10 mL; p = ns). CONCLUSIONS: A major surgical procedure impairs growth in juvenile rats. no evidence emerged from this study for additional restriction of cardiac development due to cardiac wrapping. However, studies that include stimulated muscle wraps are needed before CMP should be considered for the pediatric age group.     

Effect of mandibular and tongue protrusion on upper airway size during wakefulness

Oral appliances for the treatment of obstructive sleep apnea (OSA) produce either mandibular or tongue protrusion, and are thought to enlarge the upper airway (UA). We used videoendoscopy to measure UA cross-sectional area (CSA) and shape in the hypopharynx, oropharynx, and velopharynx during various stages of active mandibular and tongue protrusion during wakefulness in 10 patients with OSA and nine control subjects. Measurements were made in the supine position at end-tidal expiration, and were normalized to the CSA in the normal bite position. Airway shape was expressed as the anteroposterior/lateral (AP/L) diameter ratio. There were no differences between OSA patients and controls in the effects of mandibular and tongue protrusion on UA caliber. Both mandibular and tongue protrusion increased CSA in the hypopharynx and oropharynx (p < 0.001), whereas only tongue protrusion increased CSA in the velopharynx (p < 0.001). Tongue protrusion caused a greater increase in oropharyngeal and velopharyngeal CSA than did mandibular protrusion (p < 0.05). Mandibular protrusion caused a greater increase in CSA in the hypopharynx than in the oropharynx or velopharynx (p < 0.05). Obese patients had a larger relative increase in oropharyngeal CSA with mandibular and tongue protrusion than did subjects of normal weight. Tongue protrusion increased the AP/L diameter ratio in the oropharynx and velopharynx (p < 0.001), and mandibular protrusion did so to a lesser extent in the oropharynx (p < 0.01), resulting in a more circular airway shape. We conclude that mandibular and tongue protrusion increase the CSA and alter the shape of the UA during wakefulness.     

Effect of dietary ingestion of oxalic acid on growth and reproduction in male and female Long-Evans rats

Male and female Long-Evans rats placed on a diet of Purina laboratory chow supplemented with 2.5 and 5.0% oxalic acid for a period of 70 days revealed decreased body weights and restricted growth rates. Ingestion of 5.0% oxalic acid depressed absolute organ weights of several visceral and endocrine tissues but enhanced the organ/body weight ratios of both male and female rats. Vaginal smears indicated disrupted estrous cycles.     

Effect of combined administration of insulin-like growth factor and platelet-derived growth factor on the regeneration of transected and anastomosed sciatic nerve in rats

The development and application of membrane solid phase extraction (SPE) in 96-well microtiter plate format is described for the automated analysis of drugs in biological fluids. The small bed volume of the membrane allows elution of the analyte in a very small solvent volume, permitting direct HPLC injection and negating the need for the time consuming solvent evaporation step. A programmable liquid handling station (Quadra 96) was modified to automate all SPE steps. To avoid drying of the SPE bed and to enhance the analytical precision a novel protocol for performing the condition, load and wash steps in rapid succession was utilized. A block of 96 samples can now be extracted in 10 min., about 30 times faster than manual solvent extraction or single cartridge SPE methods. This processing speed complements the high-throughput speed of contemporary high performance liquid chromatography mass spectrometry (HPLC/MS) analysis. The quantitative analysis of a test analyte (Ziprasidone) in plasma demonstrates the utility and throughput of membrane SPE in combination with HPLC/MS. The results obtained with the current automated procedure compare favorably with those obtained using solvent and traditional solid phase extraction methods. The method has been used for the analysis of numerous drug prototypes in biological fluids to support drug discovery efforts.