kaolinite and Chronic-Disease

To demonstrate progression of acute and chronic endocrinopathies in a kaolin-induced hydrocephalus model using light microscopy.. Adult male Sprague-Dawley rats (n = 48) were divided into six groups. Hydrocephalus was induced by intracisternal injection of kaolin solution in the acute and chronic kaolin groups, whereas an identical volume of sterile saline was injected into the sham groups.. Somatotropic cell concentrations were lower in the kaolin groups compared with their controls, but there was no difference in somatotropic cell concentration between the acute and chronic kaolin groups. Corticotropic cell concentrations were higher in the acute kaolin and sham groups compared with acute controls. Thyrotropic cell numbers were higher in the acute sham and kaolin groups compared with their controls, and although thyrotropic cell concentations were higher in the acute kaolin group than the acute sham group. No differences were observed between the acute and chronic controls and sham and kaolin groups regarding mammotropicand gonadototropic cell concentations.. Somatotropic cells are most affected by hydrocephalus that causes pituitary dysfunction, and this effect was more prominent under acute and chronic phases.

Topics: Acute Disease; Animals; Chronic Disease; Disease Models, Animal; Hydrocephalus; Kaolin; Male; Microscopy; Pituitary Diseases; Rats; Rats, Sprague-Dawley

OBJECTIVE There has been no established animal model of syringomyelia associated with lumbosacral spinal lipoma. The research on the pathophysiology of syringomyelia has been focused on Chiari malformation, trauma, and inflammation. To understand the pathophysiology of syringomyelia associated with occult spinal dysraphism, a novel animal model of syringomyelia induced by chronic mechanical compression of the lumbar spinal cord was created. METHODS The model was made by epidural injection of highly concentrated paste-like kaolin solution through windows created by partial laminectomy of L-1 and L-5 vertebrae. Behavioral outcome in terms of motor (Basso-Beattie-Bresnahan score) and urinary function was assessed serially for 12 weeks. Magnetic resonance images were obtained in some animals to confirm the formation of a syrinx and to monitor changes in its size. Immunohistochemical studies, including analysis for glial fibrillary acidic protein, NeuN, CC1, ED-1, and caspase-3, were done. RESULTS By 12 weeks after the epidural compression procedure, syringomyelia formation was confirmed in 85% of the rats (34 of 40) on histology and/or MRI. The syrinx cavities were found rostral to the epidural compression. Motor deficit of varying degrees was seen immediately after the procedure in 28% of the rats (11 of 40). In 13 rats (33%), lower urinary tract dysfunction was seen. Motor deficit improved by 5 weeks after the procedure, whereas urinary dysfunction mostly improved by 2 weeks. Five rats (13%, 5 of 40) died 1 month postoperatively or later, and 3 of the 5 had developed urinary tract infection. At 12 weeks after the operation, IHC showed no inflammatory process, demyelination, or accelerated apoptosis in the spinal cords surrounding the syrinx cavities, similar to sham-operated animals. CONCLUSIONS A novel experimental model for syringomyelia by epidural compression of the lumbar spinal cord has been created. The authors hope that it will serve as an important research tool to elucidate the pathogenesis of this type of syringomyelia, as well as the CSF hydrodynamics of the lumbar spinal cord.

Topics: Animals; Chronic Disease; Disease Models, Animal; Epidural Space; Immunohistochemistry; Kaolin; Laminectomy; Lumbar Vertebrae; Magnetic Resonance Imaging; Male; Motor Activity; Movement Disorders; Rats, Sprague-Dawley; Spinal Cord; Syringomyelia; Urination

Ventriculomegaly occurs when there is imbalance between creation and absorption of cerebrospinal fluid (CSF); even when treated, long-term behavioral changes occur. Kaolin injection in the cisterna magna of rats produces an obstruction of CSF outflow and models one type of hydrocephalus. Previous research with this model shows that neonatal onset has mixed effects on Morris water maze (MWM) and motoric performance; we hypothesized that this might be because the severity of ventricular enlargement was not taken into consideration. In the present experiment, rats were injected with kaolin or saline on postnatal day (P)21 and analyzed in subgroups based on Evan's ratios (ERs) of the severity of ventricular enlargement at the end of testing to create 4 subgroups from least to most severe: ER0.4-0.5, ER0.51-0.6, ER0.61-0.7, and ER0.71-0.82, respectively. Locomotor activity (dry land and swimming), acoustic startle with prepulse inhibition (PPI), and MWM performance were tested starting on P28 (122cm maze) and again on P42 (244cm maze). Kaolin-treated animals weighed significantly less than controls at all times. Differences in locomotor activity were seen at P42 but not P28. On P28 there was an increase in PPI for all but the least severe kaolin-treated group, but no difference at P42 compared with controls. In the MWM at P28, all kaolin-treated groups had longer path lengths than controls, but comparable swim speeds. With the exception of the least severe group, probe trial performance was worse in the kaolin-treated animals. On P42, only the most severely affected kaolin-treated group showed deficits compared with control animals. This group showed no MWM learning and no memory for the platform position during probe trial testing. Swim speed was unaffected, indicating motor deficits were not responsible for impaired learning and memory. These findings indicate that kaolin-induced ventriculomegaly in rats interferes with cognition regardless of the final enlargement of the cerebral ventricles, but final size critically determines whether lasting locomotor, learning, and memory impairments occur.

Topics: Animals; Chronic Disease; Disease Models, Animal; Hydrocephalus; Kaolin; Learning Disabilities; Male; Maze Learning; Memory Disorders; Mental Disorders; Movement Disorders; Rats; Rats, Sprague-Dawley; Weaning

We propose that a clay derived class of materials, known as geopolymers, may solve the problem of finding materials for controlled release with the right combination of properties necessary for a safe and sustained oral delivery of highly potent opioids. We show that the opioid Fentanyl, and its structurally similar sedative Zolpidem, can be embedded into metakaolin based geopolymer pellets to provide prolonged release dosage forms with mechanical strengths of the same order of magnitude as that of human teeth. The results presented in the current work may open up new opportunities for future development of drug delivery for high potency drugs employing high-strength and variable-pore-structure geopolymers and materials alike.

Topics: Analgesics, Opioid; Chronic Disease; Compressive Strength; Delayed-Action Preparations; Fentanyl; Humans; Hypnotics and Sedatives; Kaolin; Pain; Polymers; Pyridines; Zolpidem

Joint mobilization is a common treatment used by healthcare professions for management of a variety of painful conditions, including inflammatory joint and muscle pain. We hypothesized that joint mobilization would reduce the bilateral hyperalgesia induced by muscle and joint inflammation. Mechanical hyperalgesia was measured by examining the mechanical withdrawal threshold of the rat's paw before and after induction of inflammation with 3% carrageenan (gastrocnemius muscle) or 3% kaolin/carrageenan (knee joint), and for 1 hour after knee joint mobilization. The mobilization consisted of rhythmically flexing and extending the knee joint to the end of range of extension while the tibia was simultaneously moved in an anterior to posterior direction. A bilateral decrease in mechanical withdrawal thresholds occurred 1, 2, and 4 weeks after inflammation of the knee joint or muscle. In animals with muscle inflammation, mobilization of the knee joint increased the mechanical withdrawal threshold bilaterally when given 1, 2, or 4 weeks after inflammation. However, in animals with knee joint inflammation, mobilization of the knee joint at 4 weeks increased the mechanical withdrawal threshold but had no effect when administered 1 or 2 weeks after inflammation. Therefore, joint mobilization reduces hyperalgesia induced by chronic inflammation of muscle and joint.. This article shows that unilateral joint mobilization reduces bilateral hyperalgesia induced by chronic muscle or joint inflammation. Understanding the pain conditions in which mobilization produces an analgesic effect should assist the clinician in selecting appropriate treatment techniques. The bilateral effect suggests that central mechanisms could mediate the analgesia.

Topics: Animals; Arthritis; Carrageenan; Chronic Disease; Hyperalgesia; Joints; Kaolin; Male; Myositis; Pain Measurement; Pain Threshold; Rats; Rats, Sprague-Dawley

The goal of this investigation was to establish whether pressure gradients exist between the ventricles, brain tissue, and subarachnoid space when acute or chronic hydrocephalus develops. Such gradients are hypothesized by many models of hydrocephalus, but considerable controversy continues about their existence.. A stereotactic frame was used for surgery in dogs to implant pressure sensors within the right lateral ventricle, the frontal lobe, and forward in the subarachnoid space. The dogs were allowed to recover for 10 to 14 days postoperatively. Then, 800 mg of sterile kaolin in water was injected into the cisterna magna region by using a percutaneous approach. Both real-time and long-term intracranial pressures were measured. Of the six dogs, one experienced an intracranial hemorrhage, one dog displayed status epilepticus after a second injection of kaolin and was killed, one experienced acute hydrocephalus, and three experienced mild chronic hydrocephalus. No consistent pressure differences were found in any dog between the ventricle, brain, and subarachnoid space before kaolin administration or afterward when hydrocephalus developed. In addition, no pulse pressure gradients occurred between the brain and the ventricle or subarachnoid space.. Precise monitoring of pressure before and during the development of hydrocephalus did not detect pressure gradients between the ventricle, brain, and subarachnoid space. This was true for long-term measurements over weeks and for real-time measurements that allowed accurate assessment of pulse pressures. Theories predicting pressure gradients greater than the resolution of these sensors (0.5 mm Hg) across brain tissue have to be reevaluated in light of these findings.

Topics: Acute Disease; Animals; Blood Pressure; Cerebral Ventricles; Chronic Disease; Disease Models, Animal; Dogs; Hydrocephalus; Intracranial Pressure; Kaolin; Monitoring, Physiologic; Subarachnoid Space

Chronic hydrocephalus that begins in childhood and progresses only very gradually is sometimes called "arrested" hydrocephalus. Data suggest that this state eventually can become symptomatic and may be treatable by shunting. However, the pathological substrate of the disorder is not entirely understood. We studied chronic hydrocephalus in rats, 9 months after induction by kaolin injection into the cisterna magna, and in humans. In both circumstances, destruction of periventricular white matter structures was worst in those with the largest ventricles. Structures damaged include the corpus callosum, corticospinal tract, and fimbria/fornix projections from the hippocampus. Myelin turnover was increased. These changes were associated with deficits of motor and cognitive function. The cerebral cortex was largely spared. There appears to be a threshold of ventricle size beyond which functional changes manifest, but this undoubtedly is modified by factors such as age of onset and rate of enlargement. These data support the need for persistent follow-up of patients with chronic, apparently stable hydrocephalus. A slight increase in size of already enlarged ventricles might cause significant axonal damage.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Axons; Brain; Cerebral Ventricles; Child; Child, Preschool; Chronic Disease; Cognition Disorders; Humans; Hydrocephalus; Infant; Kaolin; Male; Middle Aged; Motor Skills Disorders; Myelin Sheath; Rats; Rats, Sprague-Dawley; Statistics, Nonparametric

The article represents features for differential diagnosis between pulmonary tuberculosis and dust diseases in workers engaged into mullite refractories production. The author suggests possible course of the disease as a new type of chronic pulmonary malady--mullitosis.

Topics: Aluminum Compounds; Catchment Area, Health; Chronic Disease; Humans; Industry; Kaolin; Lung Diseases; Mineral Fibers; Occupational Diseases; Russia; Tuberculosis, Pulmonary

Hydrocephalus is associated with gradual progressive impairment and destruction of cerebral axons and neurons. To provide a comprehensive analysis of gene expression changes in brain due to experimental hydrocephalus we used a DNA microarray screening technique. Hydrocephalus was induced in 3-week-old and 8- to 10-week-old rats by injection of kaolin into cisterna magna. Following induction of hydrocephalus, samples of frontoparietal cerebrum were studied 3 and 36 weeks later in young rats and 1.5 weeks later in adult rats. At the transcriptional level, young rats with subacute hydrocephalus showed overexpression of genes involved in synaptic transmission in parallel to genes associated with protective and compensatory mechanisms. Those with chronic hydrocephalus exhibited some similar changes among synapse-related genes but suppression of other neuronal genes. Expression of myelin-related genes was increased in both groups of rats with early onset hydrocephalus but suppressed in adult rats with acute hydrocephalus. Changes in genes related to extracellular matrix molecules suggest that there might be remodeling in this compartment. Adult rats showed elevated expression of inflammatory genes, likely related to kaolin-induced inflammation, but they failed to show changes in genes involved in compensatory or protective mechanisms. These results indicate that there is an age- and duration-dependent difference in the gene expression profiles of kaolin-induced hydrocephalus and they present avenues for future research.

Topics: Aging; Animals; Chronic Disease; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation, Developmental; Hydrocephalus; Kaolin; Magnetic Resonance Imaging; Male; Nerve Tissue Proteins; Oligonucleotide Array Sequence Analysis; Rats; Rats, Sprague-Dawley; RNA, Messenger; Telencephalon

Topics: Air Pollutants, Occupational; Aluminum Silicates; Bronchitis; Chronic Disease; Crystallization; Dust; Free Radicals; Humans; Kaolin; Models, Theoretical; Occupational Diseases; Pneumoconiosis; Risk Factors; Silicon Dioxide; Silicosis; Thermodynamics

The authors proved variable clinical and pathogenetic features of disease in workers under long occupational exposure to dust of kaolin and its baking products. Therefore, special experimental studies should cover kaolin and mullite as primary and final product in entire technologic sequence of high-alumina refractories production. Natural refractory clay and mullite dust were administered to rats intratracheally during chronic experiments. Lungs of the rats exposed to mullite dust demonstrated reliable changes of lipid content in 1 month and those of hydroxyproline content--in 3 months. When exposed to intratracheal administration of kaolin and mullite dust, respiratory system develops typical changes--slow development of benign diffuse and sclerotic form of pneumoconiosis that is associated or, more frequently, preceded by chronic dust bronchitis.

Topics: Animals; Bronchitis; Chemical Industry; Chronic Disease; Dust; Humans; Hydroxyproline; Kaolin; Lung; Male; Occupational Diseases; Rats

The severity and progression of ventricular enlargement, the occurrence of cerebral edema, and the localization of ischemic metabolic changes were investigated in a rat model of hydrocephalus, using in vivo 1H MR spectroscopic imaging (SI) and diffusion weighted MRI (DW MRI). Hydrocephalic rats were studied 1, 2, 4, and 8 weeks after injection of kaolin into the cisterna magna. Parametric images of the apparent diffusion coefficient (ADC) revealed a varying degree of ventriculomegaly in all rats, with different time courses of ventricular expansion. Extracellular white matter edema was observed during the early stages of hydrocephalus, most extensively in cases of progressive ventriculomegaly. In gray matter regions, ADC values were not changed, compared with controls. In case of fatal hydrocephalus, high lactate levels were observed throughout the whole brain. In all other rats, at all time points after kaolin injection, lactate was detected only in voxels containing cerebrospinal fluid. This suggests accumulation of lactate in the ventricles, and/or an ongoing periventricular production of lactate as a consequence of cerebral ischemia in experimental hydrocephalus.

Topics: Acute Disease; Analysis of Variance; Animals; Brain; Brain Edema; Brain Ischemia; Chronic Disease; Diagnosis, Differential; Disease Models, Animal; Hydrocephalus; Kaolin; Lactic Acid; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Rats; Rats, Wistar; Time Factors

In human hydrosyringomyelia and in the late stage of experimental syringomyelia, the spinal cord tissue adjacent to the syrinx is exposed to a similar pathophysiologic condition. We investigated the ultrastructural changes in the late stages of kaolin-induced syringomyelia, and in addition, we presented magnetic resonance imaging (MRI) findings of the cervicomedullary junction and syrinx, and the nature of edema in the spinal cord of this experimental model.. Syringomyelia was induced in rabbits by intracisternal injection of kaolin. MRI was performed at 6 weeks, and 6 and 12 months following injection, and the animals were killed by transcardial perfusion of formaldehyde solution and examined by transmission electron microscopy. Evans blue was injected intravenously in six rabbits, 6 weeks and 12 months following kaolin injection and was examined by confocal laser scanning microscopy.. MRI showed that the syrinx communicated with the fourth ventricle in most animals. Demyelination of varying degrees and slight edematous change were seen in the perisyrinx white matter. No extravasation of Evans blue was seen by confocal microscopy. Abundant astrocytic proliferation with a large number of glial filaments was seen at the margin of the syrinx and between the axons in the perisyringeal region. The perivascular space enlargement occurred in both the gray and white matter. The endothelial junctions appeared intact. Regenerating axons and remyelination by oligodendrocytes were seen occasionally.. The MRI confirmed the communication between the fourth ventricle and the syrinx. The ultrastructural changes were almost identical to those of the early stage syrinx, but the astrocytic proliferation was more severe, and the edema was less in the late stage. The perisyrinx edema appeared to be of the interstitial type, as in hydrocephalus. Axonal degeneration and demyelination continued with abortive attempt at regeneration and remyelination in the less edematous late stage, which might be the cellular basis for the persistence or worsening of clinical symptoms and signs in the chronic stage of syringomyelia even after surgical treatment.

Topics: Animals; Chronic Disease; Disease Models, Animal; Kaolin; Magnetic Resonance Imaging; Microscopy; Nerve Regeneration; Rabbits; Spinal Cord; Structure-Activity Relationship; Syringomyelia; Time Factors

Hydrocephalus was induced in adult greyhounds by intracisternal kaolin. Intraventricular pressure (IVP) was monitored in the conscious animal for 2 weeks using a small implantable sensor, and the time-course of IVP change was characterized. Intraventricular pressure increased significantly within 36 h of kaolin infusion and gradually subsided to normal values within 1 week. Enlargement of the lateral ventricles was not observed during the early phase of intracranial hypertension (less than 2 days). Evolving hydrocephalus and intracranial hypertension increased the elasticity (dP/dV) of the sagittal sinus. This effect was statistically significant (p < 0.05) and is possibly reversible in the acute stage. Normotensive hydrocephalus (1 and 2 weeks after kaolin) was associated with an irreversible increase in resistance to outflow (i.e., increased sagittal sinus elasticity). Sagittal sinus venography of animals with obvious ventricular enlargement (at least 1 week after kaolin) showed development of venous collaterals and atypical outflow pathways.

Topics: Animals; Cerebral Ventricles; Cerebrospinal Fluid Pressure; Chronic Disease; Cranial Sinuses; Disease Models, Animal; Dogs; Elasticity; Hydrocephalus; Intracranial Pressure; Kaolin; Venous Pressure

Topics: Adult; Air Pollutants; Air Pollutants, Occupational; Bronchitis; Chronic Disease; Dust; Humans; Kaolin; Middle Aged; Pneumoconiosis; Risk

Topics: Acute Disease; Animals; Cats; Cerebrospinal Fluid; Chronic Disease; Ependyma; Extracellular Space; Hydrocephalus; Kaolin; Microscopy; Microscopy, Electron; Time Factors