[Entry prevention in stables and fly population density determination methods].
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Animals↗
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Results for “Population Density--determinants”
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Lung cell population density determines the ratio of type III to type I collagens.
Cultured human lung fibroblasts produced 26 to 68% more type III collagen at confluency than at low cell density. This phenomenon occurred in cell lines from normal embryonic and adult lung tissue as well as in cultures established from fibrotic lung tissue. Modulation of the proportions of individual collagen types may be important in the genesis of pulmonary fibrosis.
Adult↗
[A new method of catching, population studies and density determinations in small mammals].
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Animals↗
Osteoporosis in unstable adult scoliosis.
New noninvasive techniques as well as conventional methods were used to evaluate skeletal mass in the following three populations of adult white women as follows: (1) 79 subjects with preexisting idiopathic scoliosis designated as unstable (US) because of the associated presence in the lumbar spine of lateral spondylolisthesis with segmental instability; (2) 67 subjects with preexisting idiopathic scoliosis without lateral spondylolisthesis designated as stable (SS); and (3) 248 age-matched nonscoliotic controls. Ages in all three groups were categorized into premenopausal (25-44 years), perimenopausal (45-54 years), and postmenopausal (55-84 years). The results showed higher scoliosis morbidity in the US compared to the SS populations. The prevalence and severity of osteoporosis were markedly increased in US versus SS populations. Femoral neck density determined by dual-photon absorptiometry techniques averaged 26% to 48% lower in all age categories of US patients compared to controls. These changes were found in the youngest age groups, indicating reductions in bone mineral content earlier in the adult life of white women with a specific type of high-morbidity US characterized by the marker of lateral spondylolisthesis.
Adult↗
Stimulation of WI-38 cell cycle transit: effect of serum concentration and cell density.
Flow microfluorometry has been used to characterize the effects of serum concentration and cell density on the initiation of cell cycle transit of stationary phase (G0) human diploid fibroblasts (strain WI-38). The concentration of serum used to stimulate these cultures had no effect on the time cells began appearing in S (the DNA synthetic period), nor on the synchrony with which they moved around the cell cycle. However, as the serum concentration increased, the fraction of the stationary phase population released from G0 increased. Cell density modulated the ability of serum to stimulate cell cycle traverse. For example, at a cell density of 1.81 X 10(4) cells/cm2, 78% of the population was sensitive to serum stimulation; whereas, when the density was increased to 7.25 X 10(4) cells/cm2, only 27% of the population could be stimulated. This effect of cell density on the serum response is not simply the result of changing the ratio of serum concentration to cell density, but appears to reflect a true modulation of the population's sensitivity to serum stimulation. These results are consistent with the interpretation that the primary action of serum is to determine the transition of cells from a non-cycling G0 state to a cycling state and that cell density determines the proportion of the population capable of undergoing this transition.
Blood↗
Characterization of functionally distinct lymphoid and myeloid cells from human blood and bone marrow. I. Separation by a buoyant density gradient technique.
A buoyant density gradient procedure for mammalian cell separation is described. Gradients of Ficoll and Hypaque in balanced salt solution were used in a zonal rotor to separate distinct leukocyte populations from human peripheral blood and bone marrow. This method possesses the advantages of uniform osmolarity, density determination by refractometry, ease of preparation of gradient solutions, large sample capacity, and low viscosity with consequent ease of sterilization. Granulocyte-monocyte colony-forming units (CFU-C) from blood and bone marrow banded as a homogeneous peak with a density of 1.056 g cm-3 on steep gradients. Recovery of CFU-C was 36% with a 7- to 9-fold enrichment on shallow gradients. Both fractionated and unfractionated peripheral blood cells were stimulated by phytohemagglutinin (PHA), Concanavalin A (Con A), and allogeneic lymphocytes. In contrast, cells from unfractionated bone marrow and cells from the light density fraction of marrow were inhibited by Con A and responded variably to PHA.
Blood Cells↗
A correlative study of ultrasound calcaneal and dual-energy X-ray absorptiometry bone measurements of the lumbar spine and femur in 1000 women.
The objectives of the study were firstly to determine the accuracy of ultrasound calcaneal measurements in the prediction of bone mineral density determinations with dual-energy X-ray absorptiometry (DXA) of the lumbar spine (LS), femoral neck (FN), and Ward's triangle (FW) in a mixed population of 1000 women, unsorted as to diagnosis, and secondly to determine the accuracy of the various site-specific measurements in predicting each other. Ultrasound measurements [stiffness, speed of sound (SOS) and broadband ultrasound attenuation (BUA)] were made with the Lunar Achilles device, and the bone mineral density (BMD) of the LS, FN and FW were determined with the Lunar DPX. The data were analyzed for correlation, sensitivity, specificity, and accuracy of various paired sites. The coefficients of correlation of the young adult t-scores in the total group between calcaneal stiffness and BMDs of the LS, FN, and FW varied between 0.53 and 0.60. Coefficients for LS versus FN and FW were 0.70 and 0.62, respectively. A comparison of SOS and BUA values obtained at the calcaneus with BMDs of the LS, FN and FW yielded correlation coefficients that varied from 0.54 to 0.56. The general accuracy of prediction of one site by another ranged from 64.2% to 74.4%, where normality was defined as a t-score > -2. It is concluded that no site can predict the status of another site with sufficiently high accuracy to be clinically useful. The role of ultrasound transmission in bone as a predictor of fracture risk is theoretically promising, but has yet to be proved by a long term prospective study.
Absorptiometry, Photon↗
Long-term metabolic effects of urinary diversion: a comparison of myelomeningocele patients managed by clean intermittent catheterization and urinary diversion.
We previously reported that chronic urinary diversion through intestinal segments may have adverse effects on bone and mineral metabolism. This study examined the long-term health of patients managed by urinary diversion (94% by ileal conduit) for neuropathic bladders secondary to myelomeningocele defects and compared them to a control population of myelomeningocele patients managed by intermittent catheterization. Of the patients 93 were studied by personal interview, chart review, morphometric analysis, serum studies and dual-photon bone density determination. Average followup was 23 +/- 6 years in the urinary diversion group and 17 +/- 5 years in the intermittent catheterization group. Fractures occurred in 40% of the patients in both groups. Patients with a urinary diversion had an increased need for surgery to correct spinal curvature (57% versus 40%) and a significantly increased incidence of complications resulting from orthopedic procedures (17% versus 3%, p less than or equal to 0.05). There was also an adverse effect on renal function. The urinary diversion group had an increased incidence of radiographic renal deterioration (57% versus 8%, p less than 0.001), nephrolithiasis (43% versus 2%, p less than 0.001), pyelonephritis (60% versus 21%, p less than 0.001) and intermittent metabolic acidosis (20% versus 5%, p = 0.05). Surgery was required in 37% for stomal complications and in 17% for ureterointestinal stricture. Linear growth was adversely affected by urinary diversion. Patients with urinary diversion had decreased lengths for all morphometric parameters and a greater percentage of them were at or below the 10th percentile standards. Serum electrolytes, liver function studies, vitamin D3 and parahormone showed no differences in the 2 groups. No patient had a significant metabolic acidosis at the time of study. Bone densities were significantly diminished in both groups and not significantly different. This study strongly suggests that urinary diversion through intestinal segments is associated with adverse effects on bone health.
Bone Density↗
Neuroreceptor changes in the putamen of alcohol abusers.
The purpose of this study was to determine if alcohol abuse affects muscarinic cholinergic and benzodiazepine receptors in histologically normal brains obtained at autopsy in a general hospital population. Patients were excluded from this study if they had clinical brain (including Wernicke's) disease, died in coma, had liver disease, significant brain atrophy, or dementia severe enough to require institutionalization. We found that muscarinic cholinergic synaptic receptor density determined with [3H]quinuclidinyl benzilate was decreased by 40% in homogenates of the putamen of 27 alcohol abusers compared with 37 matched nonalcoholic controls. In contrast, receptor densities and affinities of benzodiazepine receptors determined with [3H]flunitrazepam were not significantly different in the two groups. Age and death-autopsy time interval had no significant effects on either wet tissue protein concentrations, yields of protein after centrifugation, or receptor binding. The contributions of age and time interval were each less than 3% of the total variance of protein concentrations and receptor binding. When patients who had received cholinergic, anticholinergic, or benzodiazepine medications before death were excluded or included we observed no significant effects on the final results. Pneumonia, known to be associated with acute hypoxia, and chronic obstructive pulmonary disease, known to be associated with chronic hypoxia, were approximately equally distributed between the two groups and had no significant effects on the results reported here. It is significant that the loss of muscarinic and the sparing of benzodiazepine receptors in the putamen occurs in histologically normal brains in the absence of significant atrophy and gross dementia. It implies that these changes are early in the development of alcoholic encephalopathy.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Loss of muscarinic cholinergic receptors from the temporal cortex of alcohol abusers.
It is currently controversial whether all the brain damage in alcohol abusers in the result of thiamine deficiency (Wernicke-Korsakoff's disease) or whether, in addition, alcohol abuse may affect the brain by other mechanisms as well. The purpose of this study was to determine if alcohol abuse affects muscarinic cholinergic and benzodiazepine receptors in histologically normal brains obtained at autopsy in a general hospital population. Patients were excluded from this study if they had clinical brain diseases (including Wernicke's disease), died in coma, or had liver disease, significant brain atrophy, or dementia severe enough to require institutionalization. We found that muscarinic cholinergic synaptic receptor density determined with [3H] quinuclidinly benzilate was decreased by 40% in homogenates of the tempeoral cortex of 26 alcohol abusers compared with 26 matched nonalcoholic controls. The affinities of the muscarinic receptors were not significantly different between the two groups. In contrast, receptor densities and affinities of benzodiazepine receptors determined with [3H]flunitrazepam were not significantly different in the two groups. Age and death-autopsy time interval had no significant effects on either wet tissue protein concentrations, yields of protein after centrifugation, or receptor binding. The contributions of age and time interval were each less than 2% of the total variance of protein concentrations and receptor binding. When patients were excluded or included who had received cholinergic, anticholinergic, or benzodiazepine medications before death, no significant effects on the final results were observed. Pneumonia, known to be associated with acute hypoxia, and chronic obstructive pulmonary disease, known to be associated with chronic hypoxia, where approximately equally distributed between the two groups and had no significant effects on the results reported here. The loss of muscarinic and the sparing of benzodiazepine receptors occurs in the temporal cortex of histologically normal brains in the absence of significant atrophy and of gross dementia. This means that these changes are early in the development of an alcohol encephalopathy. We have previously reported a decrease in both muscarinic and benzodiazepine receptor binding in the frontal cortex and a decreasing muscarinic but not benzodiazepine receptors in the temporal cortex of alcohol abusers. Taken together, these findings suggest that alcohol neurotoxicity does not simply result in a random loss of neurons and or their associated synapses with their receptors. Instead, different types of receptors, depending upon their location in different brain regions, are specifically affected or spared. This suggests the involvement of region- and receptor-specific mechanisms in chronic alcohol toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)
Aged↗
Criteria for diagnosing clinical malaria among a semi-immune population exposed to intense and perennial transmission.
In highly malaria-endemic areas, thick smears are usually positive regardless of the clinical context. Therefore the simple positivity or negativity of the thick smear is not an adequate criterion for distinguishing malaria from other causes of fever. In order to define simple parasitological and clinical criteria for diagnosing clinical malaria with a small risk of error, a study was undertaken in a rural area in the Congo where malaria transmission is intense and perennial. Results of the systematic determination of the parasite density of 1562 samples from persons of all ages considered representative of the population of the studied area are compared to those from 327 febrile patients, 204 patients detected during medical consultations held in the villages and 123 febrile schoolchildren detected during surveys for fever. The analysis of the clinical data and the parasitological results clearly demonstrates the importance of the parasite density determination for the diagnosis of clinical malaria. Clinical Plasmodium falciparum malaria is unlikely to occur in children under 15 years if the parasite/leucocyte ratio is less than 1.5. On the contrary this diagnosis is very probable if the parasite/leucocyte ratio is higher than 2. Clinical criteria were too non-specific to serve as useful diagnostic criteria.
Adolescent↗
Complexity of the structure of particles containing heterogeneous nuclear RNA as demonstrated by ribonuclease treatment.
Brain ribonucleoprotein particles containing heterogeneous nuclear RNA (hnRNA) and a large number of polypeptides ranging from 23000 to 150000 molecular weight were treated with pancreatic and T1 ribonucleases at low (0.1 or 0.5 microng plus 5 or 25 units/ml), high (2 microng plus 100 units/ml) and very high (20 microng plus 1000 units/ml) concentrations. At low enzyme concentration, a large fraction of the particle material accumulated at 35-45 S. The accumulation was more marked for proteins in the 30000-38000 molecular weight range. Heterogeneous complexes containing a large spectrum of proteins with a characteristic distribution were disclosed between 60 and 200 S. At high ribonuclease concentration the total quantity of proteins at 35-45 S decreased, but the proteins of 30000-38000 molecular weight predominated. Heterogeneous complexes were also present. Finally at very high enzyme concentration, the particles were almost entirely hydrolyzed. Only a small amount of heterogeneous complexes subsisted at 30-190 S. The RNA content of the remaining ribonucleoprotein complexes as well as its size decreased upon ribonuclease treatment as shown by CsCl density determination and electrophoretic analysis. The results suggested that the stability of the complexes depended upon protein-protein as well as RNA-protein interactions. They also showed that sequences up to 200-300 nucleotides were protected by proteins against ribonuclease. The results were compatible with the existence of at least 3 constituents in the particles. The previously defined monoparticle population accumulating at 35-45 S was heterogeneous in respect to ribonuclease sensitivity and protein composition. The 30000-38000 molecular weight proteins accumulating at low ribonuclease and predominating afterwards were assumed to belong to monoparticles alpha. Monoparticles beta contained a larger range of proteins more easily released by the enzymes. The heterogeneous complexes were a third constituent whose relationship with the monoparticles war not established yet. A large fraction of the particle phosphoproteins was associated to these complexes. On the basis of our experiments in vitro it is assumed that monoparticle alpha can be preferentially isolated from the nuclei under conditions where endogeneous ribonuclease is high and (or) not inhibited. This might explain why, in certain cases, only one or a few proteins were described in nuclear particles instead of the complete set present in the native particles.
Animals↗
Loss of muscarinic and benzodiazepine neuroreceptors from hippocampus of alcohol abusers.
Thiamine deficiency (Wernicke-Korsakoff's disease) may not be the only mechanism whereby chronic alcohol abuse affects the brain and not all alcohol-related changes may be evident morphologically. The purpose of this study was to determine if alcohol abuse affects muscarinic cholinergic and benzodiazepine receptors in the hippocampus of histologically normal brains obtained at autopsy in a general hospital population. Because patients were excluded who had significant brain atrophy and/or dementia severe enough to require institutionalization, the reported findings are presumed to be early changes in the development of an alcohol encephalopathy. In addition, patients were excluded from this study if they had clinical brain diseases (including Wernicke's disease), died in coma, had liver disease, or received medications that could potentially alter receptor binding. The reported changes in receptor binding were therefore presumed to be related to alcohol abuse per se and not an alcohol-associated condition. We found that muscarinic cholinergic synaptic receptor density determined with 3[H] quinuclidinyl benzilate was decreased by 30% in homogenates of the hippocampus of 25 alcohol abusers compared with 25 matched nonalcoholic controls. Similarly, densities of benzodiazepine receptors determined with 3[H] flunitrazepam were also decreased by approximately 30% in alcohol abusers. The affinities of both receptor types were not affected by alcohol abuse. Age and death-autopsy time interval had no significant effects on either wet tissue protein concentrations, yields of protein after centrifugation, or receptor binding. The contributions of age and time interval were each less than 2% of the total variance of protein concentrations and receptor binding.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
A single diethylcarbamazine dose for treatment of Wuchereria bancrofti carriers in French Polynesia: efficacy and side effects.
In the fall of 1988, 14 Tahitian Wuchereria bancrofti carriers were treated by a single diethylcarbamazine (DEC) 3 mg/kg dose. Determination of blood microfilarial (mf) density was carried out on days 0, 7, 14, 30, 90 and 180 using the membrane filtration technique. Clinical signs and side effects were noted during the 3 days following treatment. Complete clearance of microfilaremia was observed in two carriers (negativation rate 14%). A decrease of mf density was noted in all of the 14 carriers, ranging from 35.2 to 99.2% (median 78.75%). The percentage decrease in mf density, determined for the whole group from the geometric mean of the 14 mf counts, was 86% by day 7 and reached 95% by day 180. Side effects were observed in 10 patients (71%) of whom 3 only were unable to perform usual activities for less than 24 hours. Though it induced an incomplete initial mf clearance, a single DEC 3 mg/kg dose was effective in reducing about 90% of the microfilaremia and in sustaining this reduction over a period of six months. Such long-term reduction (comparable to that observed in W. bancrofti carriers treated with a daily DEC 6 mg/kg dose during 12 days) is likely responsible for the consistent decrease of total mf counts observed in the Tahitian population which has been treated for years with single DEC doses given every six months.
Adolescent↗
Endothelial cell density determined by specular microscopy and scanning electron microscopy.
Human eyes were photographed with a specular microscope and later examined wit a scanning electron microscope. Corneas from patients undergoing corneal transplantation in whom we were able to obtain preoperative specular micrographs were similarly analyzed. An attempt was made to correlate the counts obtained with both microscopic techniques by determining the amount of shrinkage the cornea undergoes while being processed for SEM. All specimens were counted with a planimeter. We found that the specular microscope adequately analyzes the endothelial cell density in the central and paracentral cornea of a normal eye, but because of its small sampling area specular microscopic counts are subject to significant error when dealing with nonhomogeneous populations such as postoperative cases. We found the peripheral corneal endothelial density to be less than the central endothelial density. Furthermore, we found that we could maximize the accuracy of counting by using a variable frame in a nonhomogeneous population, counting a minimum of four photographs per specimen, analyzing different areas, and analyzing larger areas.
Adolescent↗
Wet and dry bacterial spore densities determined by buoyant sedimentation.
The wet densities of various types of dormant bacterial spores and reference particles were determined by centrifugal buoyant sedimentation in density gradient solutions of three commercial media of high chemical density. With Metrizamide or Renografin, the wet density values for the spores and permeable Sephadex beads were higher than those obtained by a reference direct mass method, and some spore populations were separated into several density bands. With Percoll, all of the wet density values were about the same as those obtained by the direct mass method, and only single density bands resulted. The differences were due to the partial permeation of Metrizamide and Renografin, but not Percoll, into the spores and the permeable Sephadex beads. Consequently, the wet density of the entire spore was accurately represented only by the values obtained with the Percoll gradient and the direct mass method. The dry densities of the spores and particles were determined by gravity buoyant sedimentation in a gradient of two organic solvents, one of high and the other of low chemical density. All of the dry density values obtained by this method were about the same as those obtained by the direct mass method.
Bacillus cereus↗
Reductions of erythrocyte membrane viscoelastic coefficients reflect spectrin deficiencies in hereditary spherocytosis.
Hereditary spherocytosis is a common hemolytic anemia associated with deficiencies in spectrin, the principal structural protein of the erythrocyte membrane-skeleton. We have examined 20 different individuals from 10 spherocytosis kindreds and 2 elliptocytosis kindreds to determine the effects of different levels of spectrin deficiency on the viscoelastic properties of the erythrocyte membrane. Micropipettes were used to perform single-cell micromechanical measurements of approximately 1,000 individual cells to determine the membrane elastic shear modulus, the apparent membrane bending stiffness, and whole cell recovery time constant for the different cell populations. The membrane viscosity was calculated by the product of the shear modulus and the recovery time constant. Results show correlation between the fractional reduction in shear modulus and the fractional reduction in spectrin content (determined by spectrin radioimmunoassay) and spectrin density (determined by the ratios of spectrin to band 3 on electrophoresis gels) suggesting that membrane shear elasticity is directly proportional to the surface density of spectrin on the membrane (P less than 0.001). The apparent membrane bending stiffness is also reduced in proportion to the density of spectrin (P less than 0.001). The membrane viscosity is reduced relative to control (P less than 0.001), but the nature of the relationship between spectrin density and membrane viscosity is less clearly defined. These studies document striking relationships between partial deficiencies of erythrocyte spectrin and specific viscoelastic properties of the mutant membranes.
Elasticity↗
The impact of osteophytic and vascular calcifications on vertebral mineral density measurements in men.
To evaluate the influence of extravertebral calcification on spinal bone density determinations, we measured lumbar vertebral density in 71 hospitalized and 58 normal men using dual photon absorptiometry. The extent of vascular and osteophytic calcification was graded from lateral lumbar radiographs. Fifty-five (43%) of the subjects had identifiable osteophytes, and 86 (67%) had vascular calcifications. Despite similar ages and weights in subjects with and without ostephytes, those with osteophytes had greater spinal density (1.34 vs. 1.17 g/cm2; P less than 0.001), and there was a strong correlation between osteophyte severity and spinal density (r = 0.41; P less than 0.00001). Proximal femoral density was not different in those with and without osteophytes. The distribution of osteophytes in this population was not random, and as a result, the presence of osteophytes obscured the the relationship of bone density to age as well as the comparison of hospitalized to normal men. Vascular calcification had a minimal effect on vertebral density. In summary, osteophytic calcification exerted an important influence on the measurement of spinal bone density in men. This effect should be considered in both clinical and research applications of integral vertebral density measures.
Absorptiometry, Photon↗