The effect of activated platelet-rich plasma (PRP) on tricalcium hydroxyapatite phosphate healing in experimental, partial defects of long bone shafts in animal models.

The purpose of the study was to assess the effect of autologous activated platelet-rich plasma on healing of a bone substitute - tricalcium phosphate hydroxyapatite in experimental long bone defects using an animal model. The experiment involved an animal model of femoral defect. 24 Termond white rabbits were used in the study. We evaluated the effect of autologous platelet-rich plasma on tricalcium phosphate using classical radiology, micro-CT studies, strength tests and histological evaluation. Radiological and histological assessment did not show a beneficial effect of PRP together with a bone substitute in comparison to filling the defects only with bone replacement material. The only benefit of adding platelet-rich plasma to a bone substitute was shown in microCT imaging. Autologous, activated platelet-rich plasma combined with hydroxyapatite tricalcium phosphate has a positive effect on the remodeling of the newly formed bone tissue, increasing its density.

Autologous activated platelet-rich plasma (PRP) in bone tissue healing - does it work? Assessment of PRP effect on bone defect healing in animal models.

INTRODUCTION: Platelet-rich plasma (PRP) preparations can be used in bone tissue healing but there are numerous doubts among clinical orthopedists about effectiveness of this method. MATERIALS AND METHODS: The studies were carried out in 12 rabbits of white termond breed. In operating room we operationally generated cylindrical, unicortical defects of the diameter of 4 mm in the middle of the shafts of both femurs. The defects in the left bones were left without filling and served as controls, and 0.7 ml of the ready-to-use PRP was administered to the defects in the right bones (experimental group). We evaluated the usefulness of the diagnostic methods applied: biomechanical tests, micro-CT tests, densitometry, typical radiology, macroscopic measurements, histopathological examinations. RESULTS: The macroscopic measurements showed a statistically significant increase in the dimension in the area of the right defect filled with PRP in relation to the control group. In experimented group, the assessment of the X-ray images showed the formation of a callus cuff around the defects. Densitometric examinations showed no statistically significant differences between defects in the experimental and control group. The analysis of the micro-CT examina- tions showed an increase in the total volume of the tissue examined (Vb) and the low density tissue fraction (Vb2) in the experimental group. The biomechanical examinations revealed signi- ficant decrease in the maximum breaking force (F max) necessary to break the bone in the experi- mental group in relation to the control group. CONCLUSIONS: Platelet-rich plasma (PRP) stimulates bone formation in the area of bone defects and may accelerate bone regeneration.

[Empirical basis for breaking the tobacco smoking habit]. / Podstawy empiryczne zwalczania nalogu palenia tytoniu.

Tobacco smoking generally regarded as a form of nicotine dependence. The behavioural effects of nicotine and its relative reinforcing properties, as well as the development of tolerance and withdrawal syndrome indicate that nicotine has addiction liability, which is however not strongly marked. Nicotine replacement therapy, low nicotine smoke aerosol and citric acid aerosol as potential smoking cessation aids are discussed.

Interactions of some organic solvents: hydrocarbons and chloroalkene.

Metabolic and toxicodynamic interactions of some organic solvents in rats repeatedly treated with medium dose levels were examined. It was shown that both n-hexane and ethylbenzene significantly inhibited tetrachloroethylene metabolism during a 2-week period. n-Hexane and tetrachloroethylene enhanced metabolism of ethylbenzene whereas ethylbenzene suppressed n-hexane metabolism only at the end of the experiment. Biochemical changes, especially the drop in the level of non-protein sulfhydryl groups in tissues of rats treated with organic solvent mixtures, were significantly less pronounced than those observed after these chemicals were administered separately. These results demonstrate that metabolic interactions between hydrocarbons and chloroalkene may lead to a modification of the biological response to these compounds.

[Polychlorinated biphenyls--toxicology and health risk]. / Polichlorowane bifenyle--toksykologia--ryzyko zdrowotne.

Polychlorinated biphenyls (PCBs) were or are manufactured as commercial products. The chemical stability and lipophilicity of these compounds, and their resistance to degradation results in their persistence in the environment and bioaccumulation in animal organisms by entering of various food chains. Food, especially of animal origin, is regarded as a major source of these chemicals for man. Acute toxicity of PCB is low. However, when absorbed in low doses over longer time periods they can cause changes leading in chloracne and other hypo- and hyperplastic responses, endocrine disorders, hepatotoxicity and porphyria, reproductive toxicity and carcinogenesis. Infants fed with breast milk are at greatest risk. The health risk assessment for environmental exposure to PCB was also discussed.

Blood lead in the general population in Poland.

Lead concentration in venous blood (Pb-B) was investigated in 1122 inhabitants (including 555 children under 10 years of age) of five Polish towns with no large industrial lead emitters (group I) and in 1246 persons (707 children under 10 years of age) living in the vicinity of zinc and copper mills (group II). The samples were analysed using electrothermal atomic absorption spectrometry (ETAAS) and the performing laboratory participated in the external quality control scheme during the study period (1992-1994). In group I the mean geometric Pb-B concentrations ranged from 23.8 to 48.3 micrograms/l in females, from 42.5 to 76.8 micrograms/l in males and from 29.9 to 62.5 micrograms/l in children. In group II, the mean geometric Pb-B concentrations were significantly higher and ranged from 49.4 to 105 micrograms/l in females, from 98.5 to 149 micrograms/l in males and from 73.7 to 114 micrograms/l in children, the values decreasing as the distance from the source of emission increased. Cigarette smoking was found to bring about a significant increase in Pb-B levels for both males and females. A significant correlation was noted between Pb-B concentrations in mothers and children. The ratio between child and maternal Pb-B concentrations amounted to approximately 1.0 for group I and to about 0.5 for group II. These findings indicate the necessity of undertaking preventive activities over the lead-contaminated areas. However, the lead hazard in Poland seems to be associated with point sources of emission and hence does not concern the whole population.

[An outline of chloro-organic compound toxicology]. / Toksykologia zwiazków chloroorganicznych w zarysie.

Chloroorganic compounds, typified by the chlorinated aliphatic and aromatic hydrocarbons, especially biphenyls, naphthalenes, dibenzo-p-dioxins, dibenzofuranes and azo/xy/benzenes are, or were, manufactured as commercial products /the chlorinated biphenyls and naphtalenes/, and occur only as contaminants in commercial products /the chlorinated dibenzo- p-dioxins, dibenzofurans, and azo/xy/benzenes/. They have all become widespread in the environment. The chemical stability and lipophilicity of these compounds, and their resistance to degradation results in their persistence in the environment and concentration in the food chains. Their chemical structures are similar, i.e. they are approximate isostereomers. They act by the common receptor-mediated mechanism and produce similar toxic responses, although they vary greatly in potency. All classes of chloroorganic compounds have produced incidents of intoxication of industrial workers, the general population, and farm or wild animals. Chlorinated aromatic hydrocarbons elicit a numerous toxic effects which include body weight loss, thymic atrophy, immunotoxicity, hepatotoxicity and porphyria, chloracne and another dermal lesions, tissue-specific hypo- and hyperplastic responses, teratogenicity, reproductive toxicity, and carcinogenesis.

Circadian variations of phenacetin metabolism in rats in vivo and in vitro.

The metabolism of phenacetin in vivo and in vitro at different periods of day was investigated in rats. In rats maintained on standard LD conditions the disappearance rate of phenacetin from blood and activity of phenacetin O-deethylase in liver were the highest in the morning and the lowest in the evening. Continuous illumination, adrenalectomy, phenobarbital or proadifen abolished this difference. It is postulated that these circadian changes of microsomal metabolism of phenacetin in rats liver are not fully responsible for the rhythmical changes in the antipyretic action of this drug that was observed previously. The mechanisms of this phenomenon are discussed.

[The effect of isometric loading on diastolic left ventricular filling in healthy individuals studied by the Doppler technic]. / Vliv izometrické záteze na prubeh dopplerovsky hodnoceného diastolického plnení levé komory u zdravých osob.

The authors examined by Doppler echocardiography 30 subjects aged 21-30 years, exposed during examination to an isometric load by using a manual balloon dynamometer. The authors investigated different indicators of left ventricular filling during diastole and their indexes which evaluate indirectly the left ventricular diastolic function. The assessed correlations of some indicators with the quantitative expression of the isometric load (double product) were as follows: peak speed E - r = 0.3671 (p < 0.05), peak speed A - r = 0.6098 (p < 0.001), index of rations of peak speeds E/A - r = 0.6098 (p < 0.0001, sum of speed--time integrals TVIE + TVIA - r = 0.6469 (p < 0.001) and the time of retardation of the early filling phase of the left ventricle related to the heart rate DCT/TF - r = 0.7249 (p < 0.001). A statistically significant increase during the load was recorded in the peak speed A and a reduction of the E/A ratio (p < 0.01). The time speed integral TVIE increased (p < 0.01), both indexes TVI E + A and TVI E/A declined (p < 0.05). The time of retardation of the early filling stage to the early filling time DCT/DFT increased (p < 0.05) and DCT in relation to the heart rate DCT/TF declined significantly (p < 0.01). There was an insignificant decline of the peak speed of early filling E and its time-speed integral, TVI E. The sum of time-speed integrals TVIE + A did not change significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

[The character of left ventricular filling measured by pulsed Doppler echocardiography in patients with various degrees of arterial hypertension]. / Charakter plnení levé komory srdecní, merený pulsní dopplerovskou echokardiografií u nemocných s ruzne závaznou tepennou hypertenzí.

The authors assessed, using Doppler echocardiography under standard conditions, indicators of left ventricular filling in 95 patients, mean age 52 years, with arterial hypertension of varying severity. The patients were divided into four groups: Group I--Patients with severe hypertension and concentric hypertrophy of the left ventricle (LV). Group II--Patients with severe hypertension without organ changes. Group III--Patients with mild hypertension without organ changes. Group IV--Patients with severe hypertension, hypertrophy of the LV and signs of its failure grade II according to Killip's classification. The results were compared with findings in a group of 30 normal subjects of similar age. In all groups of patients statistically significant differences were found in the type of left ventricular filling, as compared with normal subjects. In less severe affection of left ventricular function, where impaired active relaxation of musculature predominates (groups I, II and III), the left ventricular filling during early diastole was reduced, slower and its main part was shifted to the late stage of diastole. The ratio of the late and early flow rate through the mitral orifice Av/Ev and the ration of time/rate integrals of these rates, TVIA/TVIE, were elevated, as compared with normal subjects, similarly as the time value of retardation of early diastolic flow through the mitral orifice corrected with regard to the heart rate, DT/TF. The value of maximal flow through the mitral orifice during early diastole, PFRB was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of trichloroethylene on metabolism and toxicology of benzene in rats]. / Wplyw trichloroetylenu na metabolizm i toksycznosc benzenu u szczurów.

The effect of trichloroethylene treatment on the metabolism of benzene in vivo, and on the benzene-induced hemotoxicity, was investigated. Male Wistar rats were injected subcutaneously with benzene at 0, 2.5, 5.0, 10.0 or 20.0 mmol/kg daily for 5 days. Other rats were treated with a mixture of benzene and trichloroethylene at the same doses in a molar ratio 1:1, 1:2, and 1:05. Before, during and after exposure, both total number of leukocytes and lymphocytes in peripheral blood and excretion rate of phenol in urine (free and conjugated) were measured. In rats treated with benzene alone excretion rates of both free and conjugated phenol were elevated but not proportionally with the dose of benzene. After administration of this compound at 20.0 mmol/kg increase of free phenol excretion in successive days which was correlated with number of lymphocytes in peripheral blood were observed. Biotransformation of benzene to free and conjugated phenol was suppressed by co-administration of trichloroethylene, but occasionally it was stimulated. The changes in peripheral blood corresponded well with excretion rate of free phenol in urine. Probable mechanisms of these observations were discussed.

[Evaluation of combined toxic action of benzene and ethanol in the rat fetus]. / Ocena lacznego dzialania toksycznego benzenu i etanolu na plód szczura.

It has been well evidenced that benzene exerts toxic action on mammalian fetuses. This effect may be probably modified by several xenobiotics metabolized by mixed function oxidase system. In this study the effect of ethanol on benzene metabolism and benzene-induced fetotoxicity in rats was investigated. Pregnant female Wistar rats were exposed to benzene vapor for 6 h/day from Days 8 through 15 of gestation at concentrations of 1500 and 3000 mg/m3 or combination ethanol and benzene at the same concentrations. Ethanol was administered intragastrically at a dose of 2.5 g/kg directly before exposure to benzene or 18 hrs before. An air-exposed or ethanol treated control rats were also examined. At Day 20 of gestation, the pregnant females were sacrificed and examined for possible reproductive abnormalities. The fetuses were observed for skeletal and visceral changes. The maternal blood ethanol concentrations were 180 or 0 mg/100 ml one or 18 hrs after administration of this compound, respectively. Ethanol co-administration with benzene in principle had no effect on the metabolism of benzene, whereas it reduced the conversion of benzene to free and conjugated phenol when given 18 hrs before. Ethanol administered directly before exposure to benzene increased frequency of incidence of resorption, whereas it had no effect when was given 18 hrs before. Delay of ossification of fetuses after exposure to combination of benzene and ethanol was less pronounced than in animals exposed to benzene alone. The results indicate that the fetotoxicity of benzene may be modified by ethanol.

[Modification of metabolism and toxicity of benzene by ethanol in pregnant rats]. / Modyfikacja metabolizmu i toksycznosci benzenu przez etanol u ciezarnych szczurów.

In last decade it was suggested that the metabolism and toxicity of some xenobiotics may be modified by several compounds that alter the activities of microsomal oxidative and conjugating enzymes. In present study the effect of ethanol on benzene metabolism and benzene-induced hemotoxicity in pregnant rats was investigated. Pregnant female Wistar rats were exposed to benzene vapors for 6 hr/day from Days 8 through 15 of gestation at concentrations of 1500 and 3000 mg/m3 or combination ethanol and benzene at the same concentrations. Ethanol was administered intragastrically at a dose of 2.5 g/kg directly before exposure to benzene or 18 hrs before. An air-exposed or ethanol treated control rats were also studied. Before, during and after exposure blood samples for leukocyte and lymphocyte counts were obtained and urine for free phenol and conjugated phenol determinations was collected. Exposure to benzene alone decreased the maternal body weight and reduced leukocyte and lymphocyte counts in peripheral blood. Ethanol administered directly before exposure to benzene in principle had no effect on the metabolism and toxicity of benzene. It reduced the conversion of benzene to free and conjugated phenol, and protected animals from reduction of body weight and lymphopenia when was given 18 hrs before. Obtained results indicate that the early phases of benzene metabolism and its toxicity may be modified by ethanol.

Activity of phenacetin O-deethylase in rat liver: effect of inducers and inhibitors in vivo.

A method for the determination of microsomal phenacetin O-deethylase activity in the rat liver was described. Optimum conditions in which phenacetin is enzymatically converted to N-acetyl-p-aminophenol were determined. The product of enzymatic reaction was acid-hydrolyzed while heating. The amount of p-aminophenol formed was determined by means of indophenol reaction. The described method was applied to assess activity of phenacetin O-deethylase in normal rats and rats treated with inducers or inhibitors of microsomal monooxygenases, phenobarbital, 3,4-benzpyrene, SKF 525-A and cobaltous chloride, respectively.

Barrier creams in the prevention of occupational contact dermatitis--an experimental study.

Experimental evaluation of two barrier creams has been carried out. One of these creams was composed of hydrocarbon components; the other had, in addition, silicone oil and cetaceum. The protective properties of these creams on rats and guinea pigs have been examined. It was found that investigated creams exerted an inhibiting effect on the absorption of chromium and nickel through the skin of rats from aqueous solutions. Moreover, the creams demonstrated a pronounced protective action on guinea pigs sensitized to chromium.

Doppler echocardiographic assessment of the diastolic properties of the cardiac ventricle in ischaemic heart disease.

The authors offer their experience with diastolic function assessment using Doppler echocardiography in ischaemic heart disease. Information on the diastolic properties of the ventricle is obtained from recordings of the blood flow velocity curve in mitral and tricuspid valve orifices. Doppler echocardiography, allowing to monitor the velocity curve of ventricular filling, represents one of the most modern techniques of examination. Diastolic function is commonly significantly affected by ischaemic heart disease, not only in terms of energy requirements; other factors such as the volume of venous return, extent of ischaemia, its time course, and so on, come into play. Changes in myocardial rigidity and filling pressures are two factors which exert a substantial effect on the character of inflow curves. The article describes typical recordings obtained from individual clinical manifestations of acute and chronic states in ischaemic heart disease, and reviews the still limited body of data regarding the effect of drug and/or surgical therapy on the diastolic properties of the affected ventricle.

[The effect of stimulated tachycardia on diastolic left ventricular filling in patients with ischemic heart disease]. / Vliv stimulované tachykardie na diastolické plnení levé komory u nemocných s ischemickou nemocí srdecní.

The authors examined 20 patients with ischaemic heart disease (IHD) by pulsed Doppler echocardiography before and after a load of stimulated tachycardia. The character of left ventricular filling depended on the blood pressure reading in a wedged position only in patients who had an elevated pressure (r = -0.65 and r = -0.81 resp. after a load for A/E, r = -0.62 and r = -0.79 after a load for DT). When the pressure is normal, it declines in a wedged position and the left ventricular filling in early diastole becomes protracted and the ratio of the atrial filling rises (A/E increased after the load p greater than 0.001, DT was protracted after the load p greater than 0.01). This change is due in particular to the protracted relaxation of the heart muscle. When the pressure is elevated in a wedged position, i.e. when the elasticity of the left ventricle declines, the rate of early filling rises and its duration is reduced. This relationship was more marked after the load (A/E after the load declined p greater than 0.01, DT after the load was shorter p greater than 0.001). Examination of the flow through the mitral orifice after a load by stimulated tachycardia makes it possible to differentiate patients with a mild and more severe affection of the left ventricle associated with IHD. It permits also prediction of an increased intraventricular pressure and this to monitor the course of the disease or to evaluate the success of treatment.

[Noninvasive quantification of the severity of aortic defects using the Doppler method]. / Neinvazívní kvantifikace závaznosti aortálních vad Dopplerovou metodou.

Using Doppler method (HPRF and CW regime), the authors assessed the peak velocity of flow in an aortal spurt in 41 patients with aortal stenosis. For calculation of the transaortal pressure gradient they used a modified Bernoulli equation. The values of the calculated gradients were compared with those obtained by direct manometric assessment during catheterization of the heart after an interval of several hours to five days. Combination of two Doppler techniques correlated closely with direct assessment (r = 0.811; p less than 0.001). By application of the continuity equation in the best records of spectral analysis of velocity curves the authors calculated in 8 patients the area of the reduced aortal orifice which was very close to the area calculated by means of Hakki's formula from direct haemodynamic indicators (r = 0.948; p less than 0.001). In 33 patients the authors quantified by Doppler method the severity of aortal regurgitation from the ratio of forward and backward flow in the descending portion of the aortal arch (expressed as the % regurgitation fraction--RF). The RF values correlated well with the angiographic semiquantitative scale of severity of aortal insufficiency (r = 0.805; p less than 0.001), although they enabled the authors only to make a partial differentiation of haemodynamically severe regurgitations and mild or insignificant ones. The authors conclude that the Doppler approach makes it possible to evaluate sufficiently accurately the severity of aortic valve disease (in insufficiencies the authors recommend a more comprehensive approach), which when correctly applied and interpreted, can make non-invasive clinical diagnosis more accurate and thus permits also more accurate indication of surgical treatment of these patients.

[Protective creams for prophylaxis of allergic contact dermatitis]. / Kremy ochronne w profilaktyce wyprysku kontaktowego.

Occupational medicine is interested in effective prophylaxis of skin occupational diseases. Use of protective ointments and creams makes one of prophylaxis methods of professional dermatitis. The purpose of the investigation was to evaluate both the primarily irritant and the allergic action of the two creams devised by us for protection of skin exposed to aqueous solution of electrolytes. One of these creams was composed of hydrocarbons components, the other had in addition silicone oil and cetaceum. Protective properties of these creams in patients with allergic contact dermatitis were also examined. The experiments were carried out on 10 rabbits, 75 guinea pigs, and 491 patients mainly suffering from metal (Cr, Co, Ni) and formaldehyde allergy. It was found that investigated creams do not exert primarily irritant and sensitizing effects both in animals and humans. These creams demonstrate pronounced protective action in allergy due to water soluble allergens.

[Creams protective against electrolytes--evaluation of protection in vitro]. / Kremy ochronne przeciw elektrolitom--ocena skutecznosci in vitro.

Diffusion-inhibiting effect of the barrier creams in case of some electrolytes i. e. alkalies, acids, salts of alkaline metals, and salts of heavy metals in two chambers diffusion apparatus have been determined. Protection efficiency of two own creams and two reference creams (silicone Goldschmidt's cream, Essen FRG, and "Anthydro" made by Phypro Laboratories 86270 La Roche, Posay, France) were compared. High protection efficiency of own creams, especially in case of sulfuric acid, hydrochloric acid, sodium nitrite, potassium bichromate and nickel nitrate was found. Diffusion of potassium hydroxide and sodium hydroxide did not exceed 2% of control values during 4 hrs period.