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Biomedical subjects

J Hartman

Publications and source records attributed to J Hartman.

At least 55 records · Page 3Linked to original sources
PubMed1987

Comparison of formal language therapy with supportive counseling for aphasia due to acute vascular accident.

A total of 60 right-handed patients with acute aphasia due to left hemispheral stroke were randomly assigned to two modes of therapy for six months, beginning one month after the ictus. Conventional speech therapy provided by professional speech pathologists twice weekly was compared with emotionally supportive counseling therapy, also provided by professional speech pathologists at the same intervals. Language function was tested periodically by the Porch Index of Communicative Ability. Fifty of the subjects were also tested at ten months after the ictus. There was no difference in the amount of improvement between the two groups.

Adult↗
PubMed1987

Correlation between changed biophysical properties of surface membranes and embryonic brain cell adhesivity. Influence of detergents, fixation, EGTA, colchicine, vinblastine, increased K+, ouabain and DMA on the primary cellular adhesivity of embryonic brain cell.

Embryonic mouse brain cells were rotated for 120 min and cellular adhesivity was tested under normal conditions and in the presence of substances which change the membrane properties. A marked decrease of cellular adhesivity (but not complete inhibition) was recorded in the presence of anionic detergents, while fixation of cells caused only non-significant inhibition Colchicine (1 mumol/l) and vinblastine (10 micrograms/ml) did not significantly affect the adhesivity. Increased external K+ (10 mumol/l) and ouabain (10 mmol/l) were also without a significant effect, however, EGTA (0.1 and 0.01 mmol/l) inhibited the adhesivity significantly. 2,3 dimethyl maleinic anhydride (DMA) which removes a part of the positive charge, caused a slight decrease of adhesivity. It is suggested that the primary adhesivity of brain cells is dependent upon the structural integrity of surface membranes, while the organization of the tubular system does not play a significant role. Isotonic concentration of monovalent cations is optimal for adhesivity and an increased concentration of external K+ or ouabain did not affect adhesivity significantly.

Animals↗
PubMed1987

Influence of increased concentration of Ca2+, La3+, PVP and urea on primary adhesivity of embryonic brain cells. Ultrastructural pattern of adhering cells.

With the help of a previously described experimental arrangement the influence of increased external concentration of Ca2+, La3+, PVP and urea was tested on the initial stages of brain cell adhesivity and its kinetics. Urea, an inhibitor of hydrogen bonds, significantly inhibited the adhesivity of the treated cells. PVP significantly increased cell adhesivity. The adhesivity was enhanced and speeded up by increased concentrations of Ca2+ and La3+. It is evident that the membrane surface potential, zeta potential and formation of H+ bonds and bridges are highly important for cellular adhesivity. EM control of freshly dissociated cells disclosed that a part of the cells had been damaged. According to the ultrastructural organisation, the surface membrane is damaged to a small or greater extent. Intercellular contacts were formed in vitro either between non damaged surfaces of membranes, or between fragments of membranes, or contacts were mediated by membrane debris. Because cellular debris disappeared during rotation from single adhesive complexes, it is probable, that disrupted membranes are used for restoration of membranes, or serve as a metabolic substrates, or are catabolized.

Animals↗
PubMed1986

Circahoralian changes in the size and dry mass of glioma C-6 cells in culture.

Changes in the size and dry mass of glioma C-6 intact cells in culture were investigated for 35-50 min at 5 min intervals by means of vital cytointerferometry. Rhythmic variations in the size, dry mass and protein concentration were thereby revealed in glioma cells. These variations fall into the category of circahoralian ones. While considerable variations in the cell area and dry mass were observed, changes in protein concentration were less pronounced. Addition of dibutyryl cylic AMP (db-cAMP), in a concentration of 10(-3) mol/l to the cultivation medium, produced no effect on the rhythm of the above parameters in glioma C-6 cells.

Animals↗
PubMed1986

Cell-to-cell adhesion of dissociated embryonic brain cells; the effects of metabolic inhibitors and temperature.

Brain cells from 16 to 18-day-old mice embryos were dissociated by mild trypsinization and rotated for 120 min. The area and density of of the adhesive complexes formed were registered using the method described previously. The adhesiveness of dissociated embryonic brain cells (measured during the 120 min of rotation) was diminished in the presence of inhibitors of protein synthesis (puromycin, cycloheximide and inhibition of mRNA synthesis actinomycin D). The inhibition was, however, not distinct, because 1 microgram/ml of cycloheximide and actinomycin was without any significant effect, and the degree of inhibition evoked by 10 micrograms/ml and 25 micrograms/ml of puromycin bordered on significance. However, protein synthesis inhibitors in long-term aggregation experiments had a pronounced inhibitory effect and/or induced destruction of the aggregates. Metabolic inhibitors (KCN and NaN3) caused an inhibition at the lowest level of significance (p less than 0.05) 10(-3) mol/l KCN reduced the final adhesive product significantly. Cells rotated at room temperature and at +5 degrees C adhere to the same extent as in control experiments (37 degrees C). The adhesion was significantly inhibited at +60 degrees C and also after freezing at -80 degrees C with subsequent thawing. The adhesion of cells exposed for 30 min to between +80 degrees C and 100 degrees C was completely abolished. The process of embryonic brain cell adhesion requires a low energy supply, and is relatively independent of biosynthetic processes and of temperature changes between +5 degrees C and +50 degrees C.

Animals↗
PubMed1986

Simple method for monitoring 24-hour urinary urea nitrogen excretion.

The urine urea nitrogen/urine creatinine excretion ratio (UUN/UCr) of a "spot" urine specimen obtained approximately 5 hours after the last meal of the day can be used to accurately calculate the urinary urea excretion for the previous 24-hour period. Because UUN excretion is largely determined by dietary intake of protein nitrogen, this method can be used to estimate dietary protein intake for the previous 24-hour period. Strategies for using this simple method for inexpensively and continuously monitoring dietary protein intake are discussed.

Creatinine↗
PubMed1985

The organization and differentiation of nervous cells in tissue cultures (a minireview).

Single stages of histiotypic formation from dissociated embryonic brain cells are described. The first stage, i.e. primary adhesion, is a phenomenon depending mainly on physicochemical features of the adhesive system. The composition of the membrane glycoprotein coat was studied during membrane regeneration and formation of cellular contacts. At the beginning single terminal sugar components and negative sialic acid residues are distributed non-homogeneously over the membrane according to the ligation of lectins. During the formation of cellular contacts this non-homogeneity progressively disappears, the thickness of the layer is reduced, however, the density of single markers increases. The highest increase of both density and layer thickness during the phase of membranes reparation occurs when the negative surface groups are labelled with cationized ferritin. The sorting out process was studied in mixed cultures as a stage of final specific recognition. It is assumed that the reaggregation of cells is a multistep process depending on maturation of the glycoprotein coat, characterized by multiple cellular adhesion and deadhesion, completed by specific recognition and fixation of recognized cells.

Animals↗
PubMed1985

The effect of short-term temperature changes on the adhesivity of nerve cells. Participation of DNA molecules on non-specific cellular adhesion.

Brain cells from 16 to 18-day-old mice embryos were dissociated by mild trypsinization and sieving. Immediately after dissociation the cells were preincubated in a PBS solution at -6 to +54 degrees C for 3 and 20 min. After this preincubation cells were rotated for 60 min at 37 degrees C in the PBS solution. Cellular adhesivity was estimated during this time period and EM pictures of organized in vitro aggregates after 24-28 h were taken. In a separate series of experiments, freshly dissociated were treated with DNAase before the rotation procedure. Preincubation in a cold or a warm medium did not alter the inhibition of cellular adhesivity significantly. Distinct inhibition of cellular adhesion was observed in cells preincubated above 53 degrees C. Adhesion was also inhibited below -5 degrees C, however, this effect was mainly dependent on the rate of freezing and thawing. Digestion of dissociated cells with DNAase (20 micrograms/ml) decreased cell adhesion. At 37 degrees C the adhesivity decreased by about 20%. Aggregates of cells preincubated at 0 degrees C for 20 min did not exhibit marked EM changes after 24-28 h in vitro. The present results have shown the rather high resistance of molecules responsible for cellular adhesion and its reversibility to temperature changes. Furthermore, non-specific cellular adhesion was shown on physically active DNA molecules.

Animals↗
PubMed1984

Inhibitory effect of tunicamycin on the adhesivity and aggregation of embryonic brain cells.

Tunicamycin (TM) - (0.1, 1.0 and 10 micrograms/ml) inhibits insignificantly the adhesivity of embryonic mice brain cells during the first 120 min of incubation. The effect is not dose dependent. The concentration of 10 micrograms/ml added at the onset of experiments has a drastic effect during the time period in which cell regeneration, cell movement and formation of aggregates occurs. Up to the 5th day in vitro (DIV), aggregation is completely inhibited and disrupted parts of cells are mostly present in the medium. The concentration of 1 microgram/ml is less effective, and 0.1 microgram/ml is practically without effect. EM analysis shows that tunicamycin (10 micrograms and 1 microgram/ml) diminish the regeneration and integrity of plasmatic membranes, 10 micrograms/ml of tunicamycin destroys cytoplasmatic organelles which is probably the cause of the decline of cellular regeneration and of aggregate formation. Tunicamycin (10 micrograms/ml), if added to the already formed aggregates evokes their disintegration and lower doses (1 microgram/ml) liberated cells from aggregates into the medium.

Animals↗
PubMed1984

Support of an anephric dog for 54 days with ambulatory peritoneal dialysis and a newly designed peritoneal catheter.

A bilaterally nephrectomized dog was successfully supported with peritoneal dialysis for 54 days, using a radically new design of access catheter and a human dialysis schedule designated as continuous ambulatory peritoneal dialysis. The dog remained active and alert with a stabilized blood urea nitrogen of 30 to 40 mg/dl and a serum creatinine concentration of 4 to 6.5 mg/dl. Problems encountered with the peritoneal dialysis included the propensity for developing peritonitis, anorexia, and a significant plasma protein loss in the dialysate fluid as result of leakage across the peritoneum. Protein loss coupled with anorexia produced a catabolic state, and the animal was euthanatized because of this, at postnephrectomy day 54. The development of a new catheter design alleviated the drainage problems of the straight tube Tenckhoff catheter. Its use coupled with the continuous ambulatory peritoneal dialysis schedule and detailed management techniques allowed using the anephric dog as a model of uremia. In addition, peritoneal dialysis could be a viable treatment for animals presenting with acute reversible anuric or oliguric renal failure where conservative medical management with fluids and diuretics has failed to give clinical improvement.

Animals↗
PubMed1983

Further evaluation of the CPI Repeated Item Short Form.

Cross-validated the CPI Repeated Item Short Form (RISF). Three populations (police dispatcher recruits (N = 22), college students (N = 30), and penitentiary prisoners (N = 51) were used for comparison purposes. Each S was administered the full-length CPI, from which scores for the short forms were extracted. CPI short-form comparisons were conducted by contrasting intercorrelational matrices, comparing correlations with full length CPI scales, and determining profile validity/invalidity as well as matching profile high and low points. On all of the described comparisons the RISF compared favorably relative to the only other published CPI short form (i.e., the Factor Analyzed Short Form--FASF). The authors conclude the RISF is a good approximation of the full length CPI profiles for both institutionalized and normal populations.

Female↗
PubMed1983

Developmental changes in head-circumference and mental-performance growth rates: a test of Epstein's phrenoblysis hypothesis.

Epstein's phrenoblysis hypothesis states that brain growth and mental growth occur in correlated spurts at 3-10 months and 2-4, 6-8, 10-12 or 13, and 14-16 or 17 years of age. The present study was the first to test statistically such spurts in head-circumference and mental-age growth rates and to assess any correspondence in individual differences between spurts in the two variables in a single sample of children measured serially between 2.5 and 17 years of age. While the statistically significant spurts observed in each variable did fall within the hypothesized age periods, the chance rate for such theoretical concordance was high and several hypothesized spurts were not supported. Moreover, no relationship existed within individuals between head-circumference and mental-age growth-rate patterns.

Adolescent↗
PubMed1983

Ultrastructural and protein synthetic changes in embryonic brain: cells aggregated at 0 degree C.

Cells dissociated from brains of 16 to 18 day-old mice embrya were rotated at 37 degrees C and 0 degree C for 7--8 days. While cells aggregated at 37 degrees C formed compact aggregates, cells aggregated at 0 degree C were found in clusters or were randomly distributed. Cells aggregated in the cold did not differ markedly from the controls in their ultrastructural organisation till the 2--3 day in vitro (DIV). Later, significant structural changes, such as distention of cytoplasmic membranes, destruction of mitochondrial membranes, disappearance of ribosomes, shrinkage of nuclei and disturbance of cytoplasmic membranes were apparent. On the 6--7 DIV, groups of cells were separated by a distance of 100 nm and more, and large parts of their cytoplasm disappeared and outside cell perikarya fragments of membranes appeared forming dense debris. However, even at this period some cells were found which did not show signs of degeneration. Protein synthetic activity in aggregated cells increased linearly at 37 degrees C till 7 DIV, whereas in cells aggregated at 0 degree C an inhibition of about 34% was found at 4 DIV and at 7 DIV the curve of 14C leucine incorporation declined almost to zero. It is thus evident that cells aggregated at 0 degree C maintain an almost normal ultrastructural pattern during the first days of cultivation and only protein synthetic activity is lowered. Cellular membranes, damaged during the dissociation partly regenerated even at 0 degrees C and membraneous contacts were formed between several cells.

Animals↗