Biomedical subjects
Publications and source records attributed to J Wróbel.
We fabricated a hybrid structure in which cobalt and permalloy micromagnets produce a local in-plane spin-dependent potential barrier for high-mobility electrons at the GaAs/AlGaAs interface. Spin effects are observed in ballistic transport in the range of tens of mT of the external field and are attributed to switching between Zeeman and Stern-Gerlach modes--the former dominating at low electron densities.
We report on the observation of the Ising quantum Hall ferromagnet with Curie temperature T(C) as high as 2 K in a modulation-doped (Cd,Mn)Te heterostructure. In this system field-induced crossing of Landau levels occurs due to the giant spin-splitting effect. Magnetoresistance data, collected over a wide range of temperatures, magnetic fields, tilt angles, and electron densities, are discussed taking into account both Coulomb electron-electron interactions and s-d coupling to Mn spin fluctuations. The critical behavior of the resistance "spikes" at T-->T(C) corroborates theoretical suggestions that the ferromagnet is destroyed by domain excitations.
The comparison of the reactivity to norepinephrine (NE) and angiotensin II (A II) of isolated mesenteric blood vessels obtained from rats simultaneously poisoned with lead and cadmium to those responses of rats treated singly with lead or cadmium was performed. Male Buffalo rats aged 6-8 weeks were administered intragastrically with lead (35 mg Pb/kg body wt.) and/or cadmium (5 mg Cd/body wt.), once a week for a period of 7 weeks. Control rats were given equimolar amounts of sodium acetate and/or sodium chloride. Changes in mesenteric vascular resistance due to NE and A II injections were measured ex vivo as an increase in perfusion pressure in vessels prepared by McGregor's method. The dose-response curve for NE (0.01-5.0 microg) determined for vessels of rats poisoned simultaneously with lead and cadmium was shifted to the left in comparison to controls (not poisoned rats), similarly to these determined for rats poisoned with lead or cadmium. ED(50) NE pointed out in the control group (0.83+/-0.5 microg) was significantly greater than in metal treated groups (0.44+/-0.09; 0.45+/-0.26 and 0.5+/-0.11 microg in lead, cadmium, lead and cadmium-treated rats, respectively). This study indicated a tachyphylaxis in responses of isolated mesenteric vessels to A II injected in increasing doses, and the weaker, in comparison to controls, response of vessels of rats poisoned with lead and/or cadmium to A II at a dose of 0.4 microg. The decreasing response to A II could result from changes in calcium ions transport through L-type channels in vascular smooth muscle cells, because verapamil (2.0 microM) inhibited the A II-induced vasoconstriction more weakly in rats poisoned with metals than in controls. Inhibitor of prostaglandins synthesis, ketoprofen (200 microg/ml per min.) attenuated the pressor effect of NE in blood vessels obtained from all rats, but this effect was less potent in arteries of cadmium poisoned rats. Ketoprofen also inhibited the vasoconstrictory action of A II in all groups, but this effect was lower in vessels of rats poisoned simultaneously with lead and cadmium. We suggest that the release of vasoactive prostaglandins as a consequence of endothelial angiotensin receptor stimulation changes more under the influence of metals administered to rats simultaneously than under the influence or lead or cadmium administered singly. Treatment with a nitric oxide synthase inhibitor (L-NOARG; 22 microg/ml per min.) potentiated a NE-induced pressor response in all groups. However, the increase in perfusion pressure was greater in rats poisoned with cadmium in comparison to controls. L-NOARG potentiated the A II induced vasoconstriction only in cadmium poisoned rats, also indicating a greater influence of nitric oxide in cadmium treated rat vasculature. Two-way ANOVA showed the existence of lead-cadmium interactions effects on the reactivity of rat isolated mesenteric vessels to NE, A II and papaverine.
The aim of this study was to evaluate the impact of combined exposure to lead and cadmium, used in hypertensive doses, on the reactivity of isolated mesenteric rat vessels to dopamine. Experiments were performed on 64 male Buffalo rats (195-245 g body weight) administered intragastrically with lead acetate (35 mg Pb/kg b.w.) and/or cadmium chloride (5 mg Cd/kg b.w.) once a week for seven weeks. The isolated mesenteric bed was prepared according to McGregor's method. Dopamine (800 micrograms) was injected before and during the infusion, one after the other, of angiotensin converting enzyme (0.0004 j/ml/min), ketoprofen (0.2 mg/ml/min), and losartan (0.05 mg/ml/min) or infusion of nitric oxide synthase blocker, N-omega-nitro-L-argine (22 micrograms/ml/min), verapamil (0.001 mg/ml/min), and then propranolol (0.3 mg/ml/min). The results show an unchanged, in comparison to controls, vascular effect of dopamine in lead and cadmium poisoned rats. However, these metals modified the reactivity of mesenteric vessels to endogenous angiotensin and prostaglandins mediated pressor action of dopamine.
The authors compared the concentrations of conjugated diens (CD), lipid hydroperoxides (HEPTE) and malonyl dialdehyde (MDA), in blood serum and placental tissue of 15 parturients with pregnancy induced hypertension (PIH) and 15 normotensive controls matched for gestational age. The CD and HEPTE were measured according to the Ward method, and the MDA level was quantified by means of the Ledwozyw method. In the placental homogenates of women with gestosis, levels of lipoperoxidation products were not significantly changed in comparison to the control group. In patients with PIH, the blood serum concentrations of CD, HEPTE and MDA exceeded the control values by 48.28%, 169.47% and 57.59%, respectively (p < 0.001). Lipid peroxidation seems to play an important role in pathogenesis of the pregnancy associated hypertensive disorders.
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The authors the scheme of the computerization of their orthopedic-traumatologic department. An everyday work has been markedly advanced.
In the paper, a clinical description is presented of patients referred to the Department for primary amenorrhoea in whom somatosexual disturbances have been observed. The group of patients included three cases of Turner syndrome, four cases of pure gonadal dysgenesis, three cases of feminizing gonadal syndrome. The diagnostic-therapeutic errors are shown, paying attention to the most characteristic symptoms and proper management.
The effects of verapamil (Isoptin Knoll) and calcium glubionate (Calcium Polfa) were studied on the generation of free radicals and activity of anti-oxidant enzymes in rat's gastric mucosa following the oral administration of 50% ethyl alcohol. Ethanol in this concentration caused injury to gastric mucosa as well increased the levels of peroxidation products (malonyl dialdehyde, hydroperoxides and conjugated dienes); at the same time a decreased enzyme activity was observed (superoxide dismutase, peroxidase, glutathione peroxidase, glutathione reductase, catalase). Verapamil administered before ethanol increased the ulcerogenic activity of alcohol, increased the activity of the studied antioxidant enzymes (except catalase) and caused the decrease in the levels of peroxidation products in gastric mucosa. Calcium glubionate increased the enzyme activity and showed some protective effect on gastric mucosa.
The severity of damage to gastric mucosa and the levels of malonyl dialdehyde (MDA), hydroperoxides, conjugated dienes (C.D.) as well as the activity of catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7), glutathione peroxidase (EC 1.11.1.9) and superoxide dismutase (EC 1.15.1.1.) in rat's gastric mucosa were assessed 2 hours after the oral administration of 50% ethyl alcohol by means of a stainless steel tube. It was found that 50% ethanol administered per os caused numerous ulcerous changes in gastric mucosa, increased the levels of MDA, hydroperoxides, both isoenzymes of superoxide dismutase (Cu, Zn SOD and Mn SOD), glutathione peroxidase and glutathione reductase. The interpretation of the phenomenon was presented, emphasizing the protective role of antioxidant enzymes counteracting the formation of ulcers in gastric mucosa.
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Stomatological and mycological examinations of the workers at the fusion department of the RZWM "Silesia" showed a considerable intensification of paradontium diseases (about 80% of cases). Leukoplakia and candidiasis were the most common changes found on the mucous membrane in the oral cavity. Mycological investigations carried out on the Sabourand culture showed Candida albicans in 73,7% of cases.
1. The everted gut sac technique was used to study the diurnal pattern of active calcium transport along the small intestine of adult rat. 2. In animals maintained under artificial light-dark cycle (LD 12 : 12) and fed ad libitum diets containing from 0.02 to 1% calcium, calcium transport displayed distinct rhythmic changes: it was high in dark and low in light. 3. The decrease in dietary calcium level resulted in a rise of the rhythm amplitude, of the transport maximum in darkness, as well as the mean efficiency of transport during 24 h. The length of the intestinal region with the ability for calcium transport was also increased. 4. The phase of the transport rhythm was shifted on low-calcium diet (0.02%). 5. Diurnal periodicity of calcium transport persisted in rats adapted for 25 days to constant illumination. Similar exposure to constant darkness resulted in arhythmic transport fluctuations.
The active calcium transport along the small intestine of adult rat was shown to exhibit daily rhythmic variations of considerable amplitude. Both the light-dark cycle and the time of food presentation acted as synchronizers of the rhythm observed.
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