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Biomedical subjects

R Wroblewski

Publications and source records attributed to R Wroblewski.

At least 19 recordsLinked to original sources
PubMed2000

Effects of dorsal root transection on morphology and chemical composition of degenerating nerve fibers and reactive astrocytes in the dorsal funiculus.

The morphology and chemical (elemental) composition of the dorsal funiculus of the rat spinal cord were examined 1 and 7 days after unilateral transection (rhizotomy) of the L4 and L5 dorsal roots, using light and electron microscopy as well as X-ray microanalysis. Changes were observed only in the dorsal funiculus on the side of injury and included disintegration of the axonal cytoskeleton, enlargement of axonal mitochondria, and widening of the myelin lamellae of the injured axons. X-ray microanalysis demonstrated a significant increase in intraaxonal sodium at 1 day after injury. This increase was abolished at 7 days, but at this stage there was a significant lowering of potassium in axons and myelin sheaths and of phosphorus in myelin as well as a marked increase in calcium in the axoplasm of the degenerating axons. The nonneuronal cell compartment, largely composed of astrocytes, showed elevated sodium, chlorine, and calcium and lowered potassium levels. The changes in chemical composition paralleled an increase in immunoreactivity for the calcium-binding Mts1 (S100A4) protein, which is exclusively expressed by white matter astrocytes. The influx of calcium is likely to play a crucial role in the loss of axonal integrity after rhizotomy, while the alterations in potassium, and perhaps also phosphorus, may contribute to activation of the nonneuronal cells, including the up-regulation of Mts1 expression in astrocytes.

Animals↗
PubMed1996

Elemental composition of muscle at rest and potassium levels in muscle, plasma and sweat of horses exercising at 20 degrees C and 35 degrees C.

In this study, 4 Standardbred geldings were exercised at 20 and 35 degrees C. The exercise test (ET) consisted of 2 exercise bouts separated by 2 h of rest in their boxes. Blood samples were taken before, during and after the second exercise bout and muscle (m. gluteus medius) biopsies were taken before the first exercise bout and after an intensive trot over 2600 m in the second exercise bout. The blood samples were analysed for plasma potassium and total plasma protein concentration (TPP) and the muscle fibres were analysed for elemental composition by x-ray microanalysis. The intracellular content was as follows: sodium (Na) = 40 +/- 7; magnesium (Mg) = 32 +/- 4; phosphorus (P) = 282 +/- 15; sulphur (S) = 222 +/- 13; chloride (Cl) = 119 +/- 31; potassium (K) = 304 +/- 21 and calcium (Ca) = 8 +/- 2 mmol/kg dry weight under resting conditions. Intracellular potassium content increased after exercise compared to resting values. There was a good correlation between exercise intensity, plasma potassium concentration and shifts in plasma volume, indicated by alterations in TPP. This probably reflects the very fast shift of potassium and fluid between muscle and plasma. Plasma potassium concentrations decreased below resting values post exercise. The higher dehydration degree and potassium sweat loss after exercise at 35 degrees C was not reflected in lower muscular potassium content, but by a lower plasma potassium/total plasma protein ratio after exercise, indicating less circulating potassium.

Animals↗
PubMed1995

X-ray microanalytical and morphological observations of the interface region between ceramic implant and bone.

In 8 monkeys both the maxillary lateral incisors were extracted. In the 16 extraction sites an Al2O3-ceramic dental implant (Frialit) was immediately inserted. Eight implants were submerged under the oral mucosa and the other 8 were allowed to penetrate through the mucosa during the observation period. None of the implants was loaded during the observation periods. After experimental periods of 1, 2, 4 and 8 months, the interface region between the implant and bone was examined using scanning-electron microscopy, X-ray microanalysis, back scatter, microradiography and light microscopy. The results showed that osseointegration of Al2O3-ceramic dental implant was obtained. The newly formed bone around the implant filled exactly the contours of the implant. Newly formed bone had a mineral content and a phosphorus-to-calcium ratio similar to that of the adjacent older mature jaw bone. There were no differences in the osseointegration rate between the submerged and the nonsubmerged implants. No leakage of aluminium from the implant could be detected in the bone.

Aluminum Oxide↗
PubMed1994

Concentrations of sodium, potassium, calcium, magnesium and chlorine in the muscle cells of downer cows and cows with parturient paresis.

The concentrations of sodium, potassium, calcium, magnesium, phosphorus, sulphur and chlorine, in the skeletal muscle fibres of cows with parturient paresis, downer cows, normally calving cows and unmated heifers were determined by means of an X-ray microanalysis technique. The most consistent finding was an increase in the concentration of chlorine in the muscle samples from the downer cows. There were no other significant differences between the concentrations of these elements in samples from the different groups of cows, but the calcium concentration was higher in the muscle samples collected one month after parturition than in the samples collected close to parturition.

Animals↗
PubMed1993

Growth regulation of LLC-PK1 cells: lack of effect of Na(+)-loading.

To gain more information about the growth regulation of renal epithelial cells, we examined the growth stimulatory effect of serum and intracellular sodium in the renal epithelial cell line, LLC-PK1. In subconfluent LLC-PK1 cells serum-starved for 5 days and exposed to [3H]thymidine for 24 h, 22.9% of the cells synthesized DNA. Stimulation with 10% foetal calf serum (FCS) caused an almost three-fold increase in the fraction of labelled nuclei (62.2%). Serum-starved LLC-PK1 cells exposed to 10% FCS responded with an increased abundance of c-jun transcripts. The maximal expression of the c-jun transcripts occurred at 60 min and declined 120 min after serum stimulation. It has been suggested that an increase in Na+ influx plays a role in the growth regulation of renal epithelial cells. This prompted us to study the effect of intracellular Na+ loading on the growth response of LLC-PK1 cells. Serum-starved LLC-PK1 cells were incubated in a low K+ medium or exposed to Nystatin. Incubation in a low K+ medium or with Nystatin resulted in a marked increase in intracellular Na after only 5 min. A low K+ medium did not significantly influence the intracellular pH. No effect was observed on DNA synthesis or the abundance of c-jun transcripts in LLC-PK1 cells. Nor did Na+ loading enhance the growth stimulatory effect of serum. The results suggest that an increase in intracellular sodium does not directly regulate the growth of renal epithelial cells.

Animals↗
PubMed1993

Intracellular and extracellular elemental composition of the endolymphatic sac studied by X-ray microanalysis.

X-ray microanalysis was performed along with light microscopy (LM) on rapidly frozen and cryo-sectioned endolymphatic sac tissues of adult guinea pigs, to determine the elemental composition of the different cell types in this tissue as well as the content of the sac lumen. The morphological preservation and spatial resolution of cryo-sectioned endolymphatic sac was found adequate for the identification of the different cell types of the sac in the transmission electron microscope. Further cell type identification was performed by comparing scanning transmission electron microscopy images with LM images on adjacent serial sections. X-ray microanalysis demonstrated differences between epithelial and sub-epithelial cells in the intracellular concentrations of sodium, chlorine, potassium, calcium, phosphorus and sulphur. Measurements performed in the lumen of the endolymphatic sac showed elevated sodium and decreased potassium levels as compared with the known levels of these elements in cochlear or vestibular endolymph. High phosphorus and sulphur levels were also found in the endolymph of the sac. Other morphological and analytical findings on the luminal content point out that otoconial destruction and cleaning of the endolymph from the cell debris and other products such as lipids and proteins take place in the endolymphatic sac. Our results suggest that the endolymphatic sac participates in fluid absorption (osmoregulation), ion transport and otoconial destruction. The data support the longitudinal flow theory of the endolymph.

Animals↗
PubMed1993

X-ray microanalysis of chief cells in rat parathyroid gland.

X-ray microanalysis was used to study the elemental composition of the rat parathyroid gland. Analyses were performed in morphologically defined cells. Use of semi-thin cryosections allowed us to selectively analyze cell nucleus, cytoplasm and occasionally dense granules in the cytoplasm. The concentration of elements (mmol/kg dry weight) in chief cells of parathyroid gland were as follows: Na 83, Mg 48, P 853, S 224, Cl 164, K 551 and Ca 10. Significantly higher phosphorus and potassium concentrations were found in the dense granules as compared to cytoplasm of the parathyroid chief cells. Choosing rat parathyroid gland gave the possibility to exclusively analyze chief cells. Data obtained from such a homogenous cell population will be of interest when studying human parathyroid in which chief cells are mixed together with other types of cells.

Animals↗
PubMed1992

X-ray micro-analysis of cultured respiratory epithelial cells from patients with cystic fibrosis.

X-ray micro-analysis was carried out on cultured respiratory cells from polyps removed from individuals with and without cystic fibrosis (CF). In a first set of experiments, proper experimental conditions were established. Washing the cells with 300 mmol l-1 mannitol in distilled water was found to give the best removal of the culture medium. The elemental concentrations stabilized in about 10 min after the start of the preincubation. Intracellular [Na] and [Cl] increased slightly with increasing passage number, whereas intracellular [K] decreased. Under resting conditions there were no significant differences in elemental content between CF and control cells, and there were no indications for abnormally high total [Ca] in CF cells. In normal cells, stimulation with a cAMP-analogue resulted in a decrease of cellular [Cl], whereas in CF cells an increase was measured. Exposure of both normal and CF cells to ouabain resulted in decreased [K] and increased [Na] and [Cl] level. The calcium ionophore A23187 had a similar effect on normal cells but did not affect CF cells markedly. Application of amiloride to the apical side of the cells resulted in a decrease of cellular [Na] in CF cells, whereas [Na] in control cells was not affected. The results correspond with what is known about the defective cAMP-regulated transepithelial Cl-transport in CF cells. The effect of the calcium ionophore on cellular electrolyte content is more complicated and may be the result of two separate effects: efflux of Cl- via a Ca(2+)-dependent mechanism and inhibition of the Na(+)-K(+)-ATPase by intracellular Ca2+ ions causing an influx of Na+ and Cl- ions.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1991

The sensory epithelium and its innervation in the mole rat cochlea.

The mole rat (Spalax ehrenbergi) burrows throughout its life in subterranean tunnels. Several structural and functional features which adapt the mole rat to its habitat have been discerned. The goal of this study was to elucidate the structural basis for adaptation of the auditory end-organ to an environment where low-frequency acoustical signals prevail. For this purpose, cochleae of adult mole rats were studied with light and electron microscopy. Inner hair cells throughout the cochlea, and outer hair cells in the basal (high-frequency) portion of the cochlea, were similar in structure to those seen in other mammals. In contrast, outer hair cells in the apical (low-frequency) portion displayed unique structural features. These features resembled the structure of inner hair cells or immature outer hair cells. The innervation of outer hair cells was most uncommon, in that classical medial efferent innervation was not found throughout the cochlear spiral.

Animals↗
PubMed1991

Measuring outcomes of hospital care using multiple risk-adjusted indexes.

Using existing data sources, we developed three risk-adjusted measures of hospital quality: the risk-adjusted mortality index (RAMI), the risk-adjusted readmissions index (RARI), and the risk-adjusted complication index (RACI). We describe the construction and validation of each of these indexes. After these measures were developed, we tested the relationships among the three indexes using a sample of 300 hospitals. Actual numbers of adverse events were observed for each hospital and compared to the number predicted by the RAMI, RARI, and RACI models. Then each hospital was ranked on each index. Our results showed that no relationship existed between a hospital's ranking on any one of these indexes and its ranking on the other two indexes. This result provides some evidence that no measure of quality should be used by itself to represent different aspects of the quality of hospital care. Adequate overall measures of hospital quality will need to include multiple measures in order to be credible and to reflect the complexity of hospital care. The findings suggest that consumers, payers, and policymakers cannot simply choose one hospitalwide measure, such as the mortality rate, to validly represent a hospital's performance: those hospitals with high rankings on their mortality rates do not necessarily rank high on their readmission rates or complication rates.

Abstracting and Indexing↗
PubMed1990

A low temperature vacuum embedding procedure for X-ray microanalysis of biological specimens at subcellular level.

The validity of freeze-drying and low temperature embedding in Lowicryl resins has been investigated in studies of ion distribution in mouse embryological inner ear, rat rib growth plate, liver and submandibular gland. The morphological preservation of the tissues was adequate for the identification of different intracellular compartments and extracellular structures. It was also possible to analyze extracellular fluids in the vestibular part of the developing inner ear. Compared with thin cryosections, Lowicryl sections are easier to produce and are more stable during analysis. Freeze-dried embedded material can be easily reorientated during cutting and adjacent sections can be used for other purposes such as histochemical and morphological investigations. We found that hydrophilic Lowicryl K11M, which is normally used for immunocytochemical investigations, also can be used for microanalysis. That opens the possibility for combined immunocytochemical and microanalytical studies. However, infiltration and polymerization steps have to be carried out at slightly higher temperatures than when the hydrophobic Lowicryl HM23 is used.

Acrylic Resins↗
PubMed1990

How the medicare prospective payment system affects psychiatric patients treated in short-term general hospitals.

This study's purpose was to monitor changes in hospital utilization and discharge patterns for a large national sample of Medicare psychiatric patients treated in short-term general hospitals from 1980 through 1987. We compare data on the Medicare sample with trends for psychiatric patients with Blue Cross or private health insurance who were treated in the same hospitals. Study results indicate that treatment patterns changed for the Medicare psychiatric patients. Average length of stay decreased, especially for patients treated in scatterbeds. The proportion of patients discharged to other hospitals increased, and the number of admissions dropped for those patients over age 75.

Aged↗
PubMed1989

Intracellular elemental composition of single muscle fibres in muscular dystrophy and dystrophia myotonica.

Seven patients with myotonic muscle dystrophy (MD), 6 with muscle dystrophy without myotonia (limb-girdle and facio-scapulo-humeral dystrophy) and 6 healthy volunteers were subjected to biopsy from the anterior tibial muscle (TA). Light microscopic examination of cryostat sections revealed pathological changes of different kind and degree--the occurrence of ring fibres and multiple central nuclei was the most consistent in advanced MD. X-ray microanalysis (XRMA) of single muscle fibres demonstrated the intracellular content of such elements as Na, Cl, K, Mg, S and P. The most conspicuous finding was the increase in Na and Cl and decrease in K demonstrated in MD. The highest levels of Na and Cl were found in ring fibres. Decrease in K was as high in structurally normal fibres of MD biopsies as in ring fibres and was also found in the muscle dystrophies without myotonia, but to a lesser degree than in MD. Thus, the decrease in K was not correlated to increase in Na and Cl. These changes in muscle fibre elemental content are discussed in relation to plasma membrane changes of erythrocytes in MD and especially the indications of disturbed anion channels.

Adult↗
PubMed1989

Effect of short time denervation on intracellular elemental content and fibre atrophy pattern of slow and fast twitch rat muscle.

Fast twitch extensor digitorum longus (EDL) and slow twitch soleus (S) muscles were studied after 5 and 16 days of denervation. Elemental contents of single muscle fibres were obtained with energy dispersive X-ray microanalyses (XRMA) applied on cryosections visualised in the scanning or scanning-transmission mode of electron microscopy. Cross sections in series with those produced for analytical electron microscopy were stained for enzyme histochemical fibre typing. A similar increase of Na and Cl was observed in EDL and S fibres after 16 days of denervation and a decrease of K was observed as well in EDL. This time after denervation is known to correspond to the maximal acetylcholine receptor synthesis extrajunctionally. There were no changes of elemental content after 5 days and thus the early membrane changes as i.a. fall in resting membrane potential and increased permeability for Na as well as increased endocytosis did not correspond to changes detectable by XRMA. Time course of atrophy differed between histochemical fibre types in EDL. In S all the muscle fibres atrophied earlier than in EDL and without any difference between fibre types. Then changes in elemental composition of muscle fibres after denervation do not seem to be related to degree and time course of muscle fibre atrophy.

Animals↗
PubMed1987

Changes in elemental composition of human muscle fibres following surgery and immobilization. An X-ray microanalytical study.

X-ray microanalysis of single muscle fibres visualized in the electron microscope has been applied to human muscle biopsies to quantify changes of intracellular elements after knee-surgery with subsequent immobilization for 6 weeks. An increase of intracellular chlorine (Cl; P less than 0.001) and of sodium (Na; P less than 0.1) concentrations were found 1 and 6 weeks post-surgery. Intracellular potassium (K), phosphorus and sulphur concentrations were not significantly changed. The increased Cl and Na concentrations may be an indication of a decreased activity of the ATPase-dependent Na/K-pump in the sarcolemma and/or of an increased sarcolemmal permeability for Na and Cl.

Adult↗
PubMed1986

Human and experimental lens repair and calcification.

Lens repair and calcification have been studied in an experimental rabbit model of anterior segment necrosis. Findings were compared with those in a human senile cataractous lens with subcapsular calcification. Rabbit lenses subjected to anterior segment ischemia underwent a repair process similar to that observed in perforating lens injuries. Cellular response included the formation of fibroblast-like cells that covered epithelial defects of the anterior pole. These observations suggest that the lens epithelium can transform into fibroblast-like cells. The calcification process was a non-cell-induced, and the observed mineral was probably nucleating on organic molecules. Elemental analysis demonstrated that crystals contained calcium and phosphorus with a ratio of 2:1. The mineral was probably hydroxyapatite. Since morphological findings in rabbit lenses closely resemble those of the studied cataractous human lens, the rabbit model appears to simulate one type of lens calcification in senile cataract.

Aged↗
PubMed1986

Type distribution of muscle fibres and their ultrastructure related to intracellular elemental composition as revealed by energy dispersive X-ray microanalysis. A study of multicore myopathy.

Four cases of congenital myopathy, two children and two adults, are described whose light-microscopical and ultrastructural findings are consistent with a multicore myopathy. In all cases a hereditary etiology to the disorders is obvious presumably by an autosomal recessive trait. Fibres with central nuclei and multiple minicores was a prominent finding in all cases. Energy dispersive X-ray microanalysis of single muscle fibres revealed a normal intracellular content of elements (sodium, potassium and chlorine). This is in contrast to the findings in some cases of s.c. myotubular myopathy earlier described from our group where content of sodium and chlorine is markedly increased while that of potassium is decreased. It is suggested that in myotubular myopathy membrane dysfunction causing decreased ionic gradients is an important feature of the pathophysiology while in multicore myopathy other mechanisms, as a suggestion related to mitochondrial and myofibrillar function play a more prominent part. From a diagnostic point of view it seems that X-ray microanalysis can be used to differentiate the two conditions.

Adult↗