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Biomedical subjects

S Rudnicki

Publications and source records attributed to S Rudnicki.

At least 19 recordsLinked to original sources
PubMed2000

Delayed attenuation of myocardial ischemia with repeated exercise in subjects with stable angina: a possible model for the second window of protection?

AIMS: A delayed myocardial protection extends between 24 and 96 h after ischemic preconditioning in animals. To test for this phenomenon in humans, subjects with stable angina were subjected to exercise test-induced myocardial ischemia and the effect of this "preconditioning" ischemic insult on the exercise-induced myocardial ischemia with the re-exercise after 24-96 hours was studied. METHODS AND RESULTS: Forty-eight males with a history of infarction and positive exercise test were recruited to the study. After baseline symptom-limited exercise test, the subjects were randomized to four experimental groups (n = 12/group). The groups were allowed to recover for 24 h, 48 h, 72 h or 96 h before performing the second exercise test. Variables analyzed were heart rate-systolic blood pressure product at 1 mm ST segment depression, time to 1 mm ST segment depression, maximum ST segment depression, exercise duration, and the total ischemic time. There were no intergroup differences in baseline values for these variables. All variables were significantly improved at 24 h, the improvement peaked usually at 48 h (maximum increase in the variables by 31-46%), and the variables returned to baseline by 96 h after the first test. CONCLUSIONS: The exercise-induced ischemia caused transient attenuation of myocardial ischemia with re-exercise. Although the time-window and the time-course of this effect shows striking resemblance to those of the delayed preconditioning in animals, its mechanism remains speculative. The most probable mechanisms that may be involved include increased myocardial perfusion and/or some adaptive changes in the myocardium, the delayed preconditioning being one possibility.

Adult↗
PubMed2000

A novel injectable collagen matrix: in vitro characterization and in vivo evaluation.

We present here a unique engineered collagen formulation that is injectable and compacts into a porous viscoelastic solid after implantation, achieving completely focal application without cross-linking. This implant provides a cohesive continuously porous matrix, as demonstrated by permeability and compression experiments. Those experiments also provide initial mechanical characterization of the material and establish the ability to modify these essential properties by design. Further, the short-term compaction and long-term stability of the implant in vivo in terms of both physical and histological responses are assessed in an animal model to demonstrate the mechanism of action and long-term persistence of this novel material.

Animals↗
PubMed1998

Neurotic effects of doxycycline sclerotherapy.

A patient experienced phrenic nerve paralysis after doxycycline sclerotherapy for treatment of chylous fistula at our institution. The purpose of this study is to use physiologic testing to determine whether doxycycline is capable of inducing defects in neural function. A nonrandomized, controlled trial was performed with nerve-conduction studies to determine possible deleterious effects of doxycycline sclerotherapy. Thirty-eight CD rats were used and separated into four groups. Doxycycline was applied to the sciatic nerves of rats by either topical application directly on the nerve or by intraneural injection. Nerve-conduction studies were done before surgery and at 1,7, and 21 days after surgery. The results showed a statistically significant decrement in nerve-conduction velocity and strength of transmitted impulse in those nerves injected with doxycycline solution. Complete nerve block was seen frequently. This effect was not seen with topical application of doxycycline or normal saline solution or with intraneural injection of normal saline solution. This study demonstrates that doxycycline can induce a marked decrement in neural function when applied to the subepineural layers of the sciatic nerve in the rat. Therefore doxycycline sclerotherapy should be used with great caution in situations in which it could become exposed to nerves that have sustained surgical trauma.

Administration, Topical↗
PubMed1998

[The influence of vitamin C and e or beta-carotene on peroxidative processes in persons with myocardial ischemia].

An increasing body of evidence suggests that beside hypercholesterolemia peroxidative processes and natural antioxidant defence system play important role in the development of atherosclerosis. Our earlier investigation showed the increased intensity of the peroxidative processes in the course of the acute myocardial infarction and unsatisfactory tocopherol, ascorbic acid and retinol status. The purpose of the present study was the evaluation of the effect of antioxidant vitamins supplementation by the period of 21 days on the peroxidative processes in patients after heart attack or after "bypass" admitted to the cardiological rehabilitation centre. Daily oral supplementation with vitamin C, E and beta-carotene decreased significantly plasma lipid peroxide concentration (TBARS). The highest drop in TBARS activity was found in the group after bypass. No significant effect of vitamin supplementation was observed on antioxidant enzymes activity.

Aged↗
PubMed1993

[Value of exercise test for assessment of hemodynamic efficiency of the heart].

The purpose of the work was an attempt at determination of the value of exercise test for the assessment of haemodynamic heart effectiveness. The reaction of blood pressure and heart rate to exercise was accepted as the basis for analysis. The analysis was based on a material of 40 men aged 33-66 years (mean = 51 years) with a history of myocardial infarction in whom exercise tests were carried out one year after aortocoronary bypass graft implantation. The studied men were divided into two groups A abd B depending on the reaction of blood pressure and heart rate occurring during exercise. Group A consisted of persons who responded to exercise with blood pressure and heart rate in a physiological way. The patients in group B terminated the exercise test due to pathological response. The subject of the analysis were: ischaemic changes during exercise; duration of the exercise test; attained workload in Watts; heart rhythm disturbances in group A and B; segmental left ventricular contractility disturbances evaluated on the basis of echocardiography findings. Among the patients in group B a higher percent of positive tests was found as well as shorter duration of the test and lower mean workload in relation to the patients in group A. Contractility disturbances occurred significantly more frequently - 80% among the patients in group B with greater prevalence of more sever forms of akinesis and dyskinesis (p < 0.05). Hypokinesis was observed in 7 patients (35%), akinesis in 5 cases (25%), and dyskinesis in 4 cases (20%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Electrophysiologic studies in the Guillain-Barré syndrome: effects of plasma exchange and antibody rebound.

Nerve conduction studies (NCS) and antiperipheral nerve myelin antibody (A-PNM Ab) titers were measured serially in 29 patients with Guillain-Barré syndrome (GBS), of whom 21 were treated with plasmapheresis. Data were obtained from 3 to 6 days until 1 to 2 years after onset of symptoms. Within 3 to 6 days, mean NCS were abnormal. They improved some by 1 week and became maximally abnormal by 4 to 8 weeks, during which time A-PNM Ab fell to low levels. In 5 patients plasmapheresed, A-PNM Ab fell and then increased at 4 to 8 weeks, followed by significant deterioration of NCS (P = 0.01) compared with those without antibody rebound at 18 weeks. These results suggest that, in monophasic GBS, there may be two mechanisms of conduction dysfunction such as early paranodal retraction and later demyelination. In some patients plasmapheresed, A-PNM Ab may rebound associated with further conduction dysfunction. These patients may benefit from further plasmapheresis.

Adolescent↗
PubMed1990

[Clinical evaluation of patients after aortocoronary bypass in the early postoperative period and 12 months after the treatment].

The authors discuss results of the investigation in a group of 100 male individuals aged 36-63 (mean = 50.8) after aorto-coronary by-pass surgery. The patients were randomly divided into 2 groups: rehab and control group. The evaluation of the clinical state, risk factors and physical efficiency in the preliminary investigation (right after surgery) and 12 months after medical treatment have been made. The patients from both groups at the early stage of post-surgical period do not differentiate each other in the clinical as well as physical and coronary efficiency aspects. After one year the patients from the control group featured twice as more cases with coronary instability and more frequent ventricule rhythm disturbances (32.6%) as compared to the patients from the rehab group (20.8%). The patients from the rehab and the control group following 12 months after treatment do not differentiate each other accordingly to overweight (R-group--64.6%, N-group 63.04%). The patients from rehab group following 12 months after treatment featured more frequent cases with lipid metabolism disturbances (56.2%) as compared to the control group (43.4%) where in spite of this fact, these patients featured better physical and coronary efficiency. The number of smokers in both groups is considerably diminished during the year--in R-group from 76% to 10% in control group from 58% to 17.3% respectively.

Adult↗
PubMed1989

Reduction of plasma lipid and homocysteine levels by pyridoxine, folate, cobalamin, choline, riboflavin, and troxerutin in atherosclerosis.

Elevated plasma homocysteine and lipid levels are risk factors for atherosclerosis. The plasma levels of homocysteine, determined in acid hydrolyzates of plasma, were found to be correlated with total cholesterol (r = 0.47, P less than 0.001), triglycerides (r = 0.40, P less than 0.01), and body mass index (r = 0.42, P less than 0.01) in 52 males, aged 30-60. A group of 12 male survivors of acute myocardial infarction was given pyridoxine, folate, cobalamin, choline, riboflavin, and troxerutin for 21 days. The plasma concentrations of homocysteine and alpha-amino adipic acid declined to 68% (P less than 0.001) and 57% (P less than 0.001) of the pretreatment values, and the cholesterol, triglycerides, and LDL apo B declined to 79% (P less than 0.001), 68% (P less than 0.01), and 63% (P less than 0.001) of the pretreatment values, respectively. The results suggest a new strategy for control of the metabolic abnormalities in atherosclerosis through the use of naturally occurring, non-toxic nutrients which minimize homocysteine accumulation.

Adult↗
PubMed1987

Motor neuron disease and paraproteinemia.

We studied two patients with motor neuron disease and paraproteinemia. One had amyotrophic lateral sclerosis (ALS) and IgG lambda monoclonal gammopathy. The second had slowly progressive muscular atrophy and an IgM kappa paraprotein, followed by a biclonal gammopathy when an IgA kappa paraprotein appeared. Treatment with immunosuppressive agents and plasmapheresis lowered the serum concentration of the paraproteins. The ALS syndrome progressed despite therapy. The other patient improved, was stable for several years, but then deteriorated despite continued therapy.

Aged↗