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Biomedical subjects

H Stricker

Publications and source records attributed to H Stricker.

47 records · Page 3Linked to original sources
PubMed1988

[CT kinetics of intratumor liposome deposits].

CT follow-up studies of liposome-entrapped metrizamide after intraneoplastic injection into neurogenic s.c. rat tumors were performed. By closely resembling clinical examination conditions, the experimental design has proven suitable in determining the in vivo kinetics of these interstitial liposome deposits. When compared to free metrizamide which may be considered an analogue of water-soluble chemotherapeutics, the encapsulation of metrizamide in liposomes resulted in a retarded decline of the contrast enhancement. Diffusion of liposomes could not be detected and the X-ray attenuation values measured within the liposome deposits continuously decreased with time for both types of liposomes. In the case of multilamellar vesicles, this significantly corresponded to a zero order kinetics with a mean halflife of 300 h. An initial increment in the X-ray attenuation of the liposome deposits might be due to the interstitial absorption of the water component of the liposome-dispersion. Because of the pronounced retardation effect of multilamellar liposomes resulting in a 140-fold prolongation of the interstitial retention time of metrizamide and due to their release kinetics these vesicles may be an appropriate carrier system for a local interstitial chemotherapy modality. Small unilamellar vesicles having an interstitial half-life of 14 h may be used as a faster component of a composed therapy system.

Animals↗
PubMed1988

[Factors of elimination of liposome-encapsulated drug model substances after intravenous administration].

Carboxyfluorescein (CF) and fluorescein dilaurate (FDL) have been encapsulated in either small or large multilamellar liposomes of various lipid composition. Cholesterol (CH)-free liposomes showed relatively rapid CF release when dispersed in buffer, plasma or whole blood. The same behaviour was seen with liposomes which contained a lipid whose phase transition temperature was less than 37 degrees C. The CH-free preparations also showed marked aggregation in plasma. After i.v. application to rabbits the elimination of liposomal CF was found to depend upon the typ of phospholipid present, the CH content, the surface charge and vesicle size. The lipophilic substance FDL was lost from circulation more rapidly than the hydrophilic CF. All of the measured plasma levels indicated an open two-compartment model, i.e. with two exits. The calculated microconstants provide information about the distribution kinetics.

Animals↗
PubMed1988

Optimisation of the covalent binding of monoclonal antibodies to liposomes.

Liposomes with covalently attached monoclonal antibody (mAb) may be useful for the active targeting of drugs, e.g. cytostatics, to tumor processes. For pharmacokinetic reasons the coupling reaction should be optimized with regard to the loading capacity, the number of IgG-molecules per liposome (N). The relative immunoreactivity of bound versus free mAb (r/r*) and the stability in biological fluids should be maximal, the particle size (phi) should be minimal. Furthermore, the coupling yield of the mAb should be high. This investigation was based on a previously described method, using N-hydroxysuccinimidyl-dithiopropionate for coupling anti-melanoma mAbs to liposomes composed of hydrogenated soybean lecithin, cholesterol and a dipalmitoyl-phosphatidylethanolamine derivative. Carboxyfluoresceine was used as a marker for the encapsulated phase. By systematic variation of 14 different reaction conditions a product with the following properties was obtained: N = 5, r/r* = 0.4 and phi = 120 nm. The average coupling yield was 39%. The specificity of liposomally bound mAb as assayed in in vitro tests was found to be unchanged.

Animals↗
PubMed1985

[Respiratory distress syndrome and hypothermia in Wernicke's encephalopathy].

A patient is reported who developed adult respiratory distress syndrome (ARDS) and severe hypothermia during the decompensated phase of Wernicke encephalopathy. The absence of other causes suggests a neurogenic origin for the hypothermia, possibly as a result of lesions localized in the posterior hypothalamus. A hemodynamic study during normothermia, hypothermia and rewarming showed that at body temperatures inferior to 32 degrees C the increase in pulmonary vascular resistances seems not to be the result of a real vasoconstrictor effect in the pulmonary circulation. The Wernicke-Korsakoff syndrome may have a clinical picture similar to delirium tremens, evolving into coma with complications such as hypothermia and, possibly, ARDS.

Humans↗
PubMed1984

Hyperadrenergic syndrome in severe tetanus: extreme rise in catecholamines responsive to labetalol.

The hyperadrenergic syndrome that occurs in tetanus is characterised by hypertension, tachycardia, and increased systemic arteriolar resistance. A 74 year old man with tetanus was found to have very high catecholamine concentrations--as high as those in phaeochromocytoma--and the fluctuations in blood pressure and heart rate were measured to see whether they paralleled changes in the catecholamine values. A labetalol infusion of 0.25-1 mg/min gradually stabilised the cardiovascular disturbances and the patient recovered.

Adrenergic Fibers↗
PubMed1978

[Concrete approaches to the promotion of prevention. Health education in schools].

Society nowadays entrusts the school with formative tasks which earlier were exclusively the role of the family unit. Numerous such tasks are in relation with the integration of the individual in society. As they usually concern attitudes and behaviors which the youth must actively adopt for themselves (get impregnated with), the school cannot limit its action to transmitting knowledge. This is true in particular for health education. Good mental health of the students is the precondition of a positive attitude vis-à-vis physical wellbeing. It is important therefore to give adequate emphasis to mental health requirements in teacher training.

Adult↗
PubMed1978

[Improving the effectiveness of health education].

Discussions concentrated on ways of influencing the behavior of healthy individuals. The following was concluded; 1. Health education is an interdisciplinary activity. It should not merely be aimed at the behavior of individuals but also respect and influence values and institutions of society as well as legislation. 2. Family and school are the most important fields of activity. 3. Health education should be based on experiences from communication sciences. 4. In school, health education should be integrated in as many subjects as possible. Of special importance are the example of the teachers and adequate preparation and training. 5. Health education cannot limit itself to giving information, it also must motivate to a healthy way of life. 6. Exchange of experiences and information in health education should be improved. In Switzerland this can be done by a working party of the Swiss Society for Social and Preventive Medicine. 7. The intervention trials of the Swiss National Research Program can provide important stimuli for innovative approaches to health education is Switzerland.

Adult↗
PubMedDate not supplied

Effect on intimal hyperplasia of dexamethasone released from coated metal stents compared with non-coated stents in canine femoral arteries.

PURPOSE: Polymer-coated, dexamethasone (DXM)-releasing stents were tested in order to assess the efficacy of DXM released locally for the prevention of stent restenosis due to intimal hyperplasia. METHODS: Strecker stents coated with a biodegradable membrane containing DXM were implanted percutaneously into the femoral artery in 14 dogs. The contralateral artery received a conventional non-coated stent serving as control. The drugs are eluted by degradation of the carrier membrane. Follow-up intraarterial digital subtraction angiography (DSA) was obtained at 3, 6, 9, 12, and 24 weeks with subsequent autopsy. Specimens for gross and microscopic pathology were obtained and histomorphometry was performed. RESULTS: Four of 14 DXM-coated stents showed thrombotic occlusion within the first 3 weeks; ten DXM-coated stents remained patent. At follow-up DSA, DXM-coated stents showed a significantly wider lumen than the non-coated stents. At morphometry there was less intimal hyperplasia over DXM-coated stents than over non-coated stents (p < 0.05). CONCLUSION: DXM-coated stents reduce neointimal hyperplasia in dogs when compared with non-coated stents.

Angiography↗
PubMedDate not supplied

Acute and long-term effects of prostaglandin E1 assessed by clinical and microcirculatory parameters in critical limb ischemia: a pilot study.

We treated 14 patients suffering from critical limb ischemia (CLI) as defined by the Consensus Document, and in whom possibilities of surgical or percutaneous arterial reconstruction were excluded, by PGE1 60 micrograms i.v. daily during 3 weeks. Effects were evaluated by clinical, macrocirculatory and microcirculatory parameters during a follow-up of 1 year. After treatment with PGE1, we noted a significant reduction in analgesic use and in pain score. The average tcpO2 values on the forefoot in the supine and sitting positions, with or without inhalation of O2 through a face mask, showed a significant improvement after 3 weeks, as well as capillary stage. Laser Doppler flux did not change, but was significantly higher in diabetic patients than in nondiabetics with CLI. In 4 patients (28%) no improvement could be found after 3 weeks' treatment. Although in 6 patients the improvement lasted for up to 4 months, the legs eventually deteriorated. In 4 patients (28%) the legs were preserved after 1 year without further active therapy. No patient with initial tcpO2 values above 40 mm Hg in the supine and 100 mm Hg in the sitting positions during O2 inhalation lost a leg. Although other effects like local care could have influenced the outcome favorably, we noticed a beneficial albeit transient effect of PGE1 for the majority of our patients with CLI. TcpO2 measurements with O2 inhalation might be a valuable predictor of a positive long-term result.

Adult↗