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Biomedical subjects

K Schmidt

Publications and source records attributed to K Schmidt.

At least 415 records · Page 23Linked to original sources
PubMed1988

Cellular pharmacology of liposomal cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexaneplatinum (II) in mouse resident peritoneal macrophages, Kupffer cells, and hepatocytes.

The in vitro and in vivo interaction of liposomal cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexaneplatinum++ + (II) (L-NDDP) with mouse resident peritoneal macrophages (RPM), Kupffer cells (KC), and hepatocytes was studied. The peak in vitro uptake of L-NDDP by RPM was 12.5 ng elemental platinum/100 micrograms cell protein and constituted 0.2% of the platinum available for phagocytosis. The subsequent release of platinum by RPM was rapid initially, with a 20-fold increase over the first 4 h, followed by a plateau; ultrafilterable (free) platinum constituted 50% of the total platinum released at 24 h. The retained intracellular platinum in RPM at 24 h was close to 50% of that initially present. The peak in vitro uptake of L-NDDP by KC was 11.3 ng platinum/100 micrograms cell protein and amounted to 0.2% of the platinum available for phagocytosis. The release of platinum by KC was detectable only after 4 h of incubation and increased 3-fold over the next 14 h. The ultrafilterable platinum released by KC at 18 h was 40% of the total platinum released. The retained intracellular platinum in KC at 18 h was 33% of that initially present. The peak in vitro uptake of L-NDDP by hepatocytes was almost 50 ng platinum/100 micrograms cell protein and constituted 0.8% of the platinum available for intake. Following the i.v. injection of L-NDDP, hepatocytes contained up to 6-fold higher platinum concentrations than KC. This observation was supported by transmission electron microscopy showing a higher concentration of multilamellar vesicles within hepatocytes than in KC, 5 min after i.v. injection of L-NDDP. These findings suggest that L-NDDP becomes available to the liver following i.v. injection, that both macrophages and hepatocytes play a role in the metabolism of L-NDDP, and that Kupffer cells could mediate a sustained release of platinum in the liver following the interaction with L-NDDP, indicating the potential of L-NDDP for the treatment of tumors in the liver.

Animals↗
PubMed1988

Seasonal variation of aneurysmal subarachnoid haemorrhage.

In a prospective consecutive series of 1,076 patients with aneurysmal subarachnoid haemorrhage (SAH) admitted to the 6 Danish neurosurgical departments in the 5-year period April 1, 1978 to March 31, 1983 a significantly higher seasonal incidence of SAH was seen during spring and autumn compared to summer and winter. No significant seasonal differences in monthly mortality or between females and males were registered. Contrary to several other studies concerning cerebral apoplexy excluding SAH no explanation to the seasonal variation was obtained from differences in weather conditions. A correlation between seasonal variation of aneurysm rupture and physical activity is possible.

Adolescent↗
PubMed1988

The impact of rebleeding on the life time probabilities of different outcomes in patients with ruptured intracranial aneurysms. A theoretical evaluation.

In order to strengthen patient-information a theoretical evaluation of the impact of rebleeding on the life time probabilities of different outcomes in patients with an aneurysmal subarachnoid haemorrhage (SAH) has been made using a life table method. The calculations were performed for SAH-presenting ages from 20 to 70 years assuming a rate of rebleeding of 50% in the first 6 months after the initial bleeding with a mortality rate of 70%, and the following years an annual rate of rebleeding of 3%, and with a mortality rate of 60%. A survey of the life time probabilities of the 4 different outcomes after an aneurysmal SAH shows the great life time reducing effect of rebleedings in all SAH-presenting ages.

Adult↗
PubMed1988

Human testis cytosol and ovarian follicular fluid contain high amounts of interleukin-1-like factor(s).

Human testicular cytosol and ovarian follicular fluid were analyzed for the presence of interleukin-1 (IL-1)-like factors. Both the follicular fluid and testis cytosol preparations exhibited significant IL-1-like activity as determined by the murine thymocyte proliferation bioassay. The dose-response lines obtained with the gonadal preparations were parallel to each other and to those obtained with monocyte-derived IL-1 and the activity of the gonadal IL-1 could be neutralized by specific IL-1 antibodies. After gel chromatography of human follicular fluid (hFF) and human testis cytosol (hTC) proteins, IL-1 activity was found in the molecular weight region between 30 and 50 kilodaltons (kDa). Chromatofocusing of IL-1 from hFF and hTC revealed that the major part of IL-1 in both cases exhibited similar charge properties (pI less than 6.0). However, two extra peaks (pI 7.0 and greater than 9.0, respectively) were observed in hFF preparations. After isoelectrofocusing (IEF), IL-1 activity of hFF was also found in two different pH regions; a broad area of activity was localized between pH 5.5 and 7.0, while a sharp peak was observed with an approximate pI value of 9.5. Re-chromatofocusing or IEF of alkaline IL-1-like activity resulted in a heterogeneous profile of IL-1-like activity suggesting that the alkaline material may represent either a precursor or an aggregated form of the acidic IL-1. None of the IL-1 peaks obtained from hFF or hTC exhibited IL-2 activity as assessed in a specific IL-2 bioassay. The results of the present study indicate that both gonads may produce high amounts of IL-1-like factor(s) which might play a regulatory role in normal gonadal function.

Chromatography, Gel↗
PubMed1988

A model to reproduce predictable full-thickness burns in an experimental animal.

A standardized, reproducible animal model is a prerequisite to study concepts in the therapy of extensive burn injuries. The development of a new model makes it possible to produce predetermined burn injuries with a set temperature, time, contact pressure, and standard extent of tissue damage. For our studies we chose rats and exposed them to a temperature of 250 degrees C for 20 s and a contact pressure of 500 g/cm2 over various percentages of TBSA (total body surface area). The animals received shock prophylaxis for 3 days postburn and were kept under standardized conditions in a laminar airflow compartment. The temperature was kept at 32 degrees C and the relative humidity at 75 per cent. To reduce bacterial contamination, air was filtered through special bacteria-proof filters. Under these conditions we found burns of approximately 35 per cent TBSA to be sublethal resulting in 80 per cent mortality between days 5 and 7. This model permits the investigator to vary the burned skin area to any required extent for a reproducible study of different concepts of burn therapy.

Animals↗
PubMed1988

Measurement of local cerebral protein synthesis in vivo: influence of recycling of amino acids derived from protein degradation.

A quantitative autoradiographic method for the determination of local rates of protein synthesis in brain in vivo is being developed. The method employs L-[1-14C]leucine as the radiolabeled tracer. A comprehensive model has been designed that takes into account intracellular and extracellular spaces, intracellular compartmentation of leucine, and the possibility of recycling of unlabeled leucine derived from steady-state degradation of protein into the precursor pool for protein synthesis. We have evaluated the degree of recycling by measuring the ratio of the steady-state precursor pool distribution space for labeled leucine to that of unlabeled leucine. The values obtained were 0.58 in whole brain and 0.47 in liver. These results indicate that there is significant recycling of unlabeled amino acids derived from steady-state protein degradation in both tissues. Any method for the determination of rates of cerebral protein synthesis in vivo with labeled tracers that depends on estimation of precursor pool specific activity in tissue from measurements in plasma must take this recycling into account.

Amino Acids↗
PubMed1988

Incidence and diagnosis of acute rheumatic fever in Denmark, 1980 and 1983. A retrospective analysis of the fulfillment of the revised Jones criteria in hospitalized patients.

A review of 1547 official hospital record summaries concerning discharges during the period 1980 through 1983 of patients whose diagnoses had been coded as acute rheumatic fever revealed that in only 61% of the cases had this illness been diagnosed or suspected. A substantial proportion of the remaining patients had had acute non-rheumatic pericarditis diagnosed. The medical records were analyzed for 141 patients diagnosed in 1980 or 1983 by hospital departments as having acute rheumatic fever with regard to the revised Jones criteria. They were fulfilled in 47 patients, 23 of whom were considered unlikely cases of rheumatic fever. Eight patients were considered possible cases, although they did not fulfill the revised Jones criteria. The current annual incidence of acute rheumatic fever was estimated to be at most 0.3 per 100,000 inhabitants.

Acute Disease↗
PubMed1988

Unruptured intracranial aneurysms: an assessment of the annual risk of rupture based on epidemiological and clinical data.

From autopsy and neuroradiological studies a maximum prevalence of unruptured intracranial aneurysms (UA) of 0.5% in the general population is revealed. Studies concerning the incidence of aneurysmal subarachnoid haemorrhage (SAH) revealed 10 cases per 100,000 inhabitants per year. From these epidemiological parameters a minimum annual risk of 2% of rupture of an UA is calculated. It is in accordance with clinical studies, which also demonstrated an annual risk of UA rupture of at least 2%. No critical size of the UA predisposing to rupture has been found. Operation on diagnosed UA is recommended because of the serious prognosis after aneurysmal SAH (morbidity 20%-25% and mortality 50%-60%) and because the morbidity (4%) and the mortality (0%) after operative treatment of UA are very low.

Humans↗
PubMed1988

The influence of unruptured intracranial aneurysms on life expectancy in relation to their size at the time of detection and to age.

A theoretical evaluation of the lifetime probabilities of different outcomes in patients with unruptured intracranial aneurysms (UA) has been made using a life table method. The calculations were performed for aneurysm presenting ages from 20 to 70 years of age for men and women assuming an annual risk of aneurysm rupture of 1%, 2% and 3% and a rate of mortality after rupture of 50%. At 10, 20, 30, 40, 50 and 60 years after the diagnosis of an UA the probability of survival without bleeding is reduced below the expected probability of survival according to the life tables by the following percentages (assuming an annual risk of bleeding of 2%): 19%, 34%, 46%, 56%, 64% and 72%, respectively. A survey of the lifetime probabilities of four different outcomes for patients with an UA indicates a substantial reduction in life expectancy after the diagnosis of an UA. In most ages the surgical risks are more than balanced by the risks associated with an untreated unruptured aneurysm.

Adult↗
PubMed1988

Antifibrinolytic therapy in patients with aneurysmal subarachnoid haemorrhage.

In a prospective consecutive non-randomised study including 1076 patients with ruptured intracranial aneurysms 205 patients received epsilon aminocraproic acid (EACA) and 871 did not. No significant differences between the two groups concerning clinical condition on admission, sex, age, localisation and size of the aneurysms were seen. No cases of rebleeding (RB) were observed within the first 4 days in the EACA treated patients, but within the first 48 hours, which is the optimal period recommended for operation of patients in good clinical condition, this difference of the rates of RB between EACA treated and not treated patients is not significant. A significantly lower rate of RB was observed in the EACA group within the first 2 weeks, but no significant differences in morbidity and mortality were found at the 2-year follow-up examination.

Adolescent↗
PubMed1988

Role of eicosanoids in inflammatory reactions of rats.

Nonsteroidal antiinflammatory agents of several subgroups, regarding eicosanoid-producing enzyme inhibition, have been tested in vitro and in vivo. There was no overt correlation between cyclooxygenase and/or lipoxygenase inhibition in vitro and antiinflammatory effects. It is possible that eicosanoids do not play a key role as inflammatory mediators, i.e. that the course of the life-protecting inflammatory reaction is ensured by an ensemble of mediators, cellular events and further mechanisms of the whole living organism.

Animals↗
PubMed1988

Dynamic visual acuity with telescopic spectacles: improvement with adaptation.

Telescopic spectacles are used as aids for the visually impaired in order to increase effective visual acuity. Because ocular stabilization reflexes are not fully compensatory when telescopic spectacles are worn, head motion would be expected to produce retinal image motion which could decrease visual acuity. Using 1.0 Hz sinusoids of vertical axis head rotation, we investigated the effect of head velocity and telescopic spectacle magnification on binocular dynamic visual acuity (DVA), the acuity during head motion, in 34 normally sighted subjects. The visual field peripheral to the telescopes was masked. Up to a head velocity amplitude of 30 degrees/sec, DVA was insensitive to head velocity for X2 telescopic spectacles. For X4 and, to a greater degree, X6 telescopic spectacles, DVA decreased progressively as head velocity increased. DVA measurements were repeated after a 15 min adaptation period, during which a distant video monitor was viewed using telescopic spectacles. For X4 telescopic spectacles, DVA increased significantly after adaptation. With an unobstructed peripheral visual field, initial DVA with X4 telescopic spectacles was equal to adapted DVA with peripheral vision occluded, but adaptation produced no further improvement in DVA with the peripheral field unobstructed. These data indicate that the visual acuity obtained with telescopic spectacles is substantially reduced under conditions where head motion occurs, potentially reducing the functional value of these devices in low vision rehabilitation. The adverse effect of head motion on DVA may be reduced by adaptation.

Adaptation, Physiological↗