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Biomedical subjects

H Schroeder

Publications and source records attributed to H Schroeder.

At least 91 records · Page 5Linked to original sources
PubMed1982

[Subacute and subchronic percutaneous tolerance testing (28-day and 90-day test) of epicutaneously applied dis-infectants as demonstrated by the example of peroxyethanoic acid (author's transl)].

As compared to control animals, guinea-pigs to the shaved backs of which a dose of 0.16 ml of a 0.12% solution of PES/100g. of body mass had been applied twice daily for periods of 28 and 90 d, respectively (5 d of application being followed by 2 d without treatment), showed erythema, loss of hair, slower increase in mass, increased heart rate, smaller body mass/kidney mass and body mass/spleen mass ratios, increases in leucocytes, ASAT, ALAT, LDH I and LDH III. In the 28-d test, slight inflammatory symptoms of the liver, kidneys and heart were observed in the experimental animals. These symptoms were more marked in the 90-d test, granulomata in the livers being particularly striking. A pneumonia of moderate to very marked degree is suggestive of the activation of a clinically latent PES infect whereby the inflammatory alterations in the kidneys might be explained by the formation of metastases.

Acetates↗
PubMed1977

[Mophometric study of the mouth mucosa in leukoplakia simplex].

Examination of the leukoplakia simplex of the oral cavity localized on the buccal surface and in the bottom of the oral cavity was carried out in 11 cases using the method of stereological morphometry. It was established that: 1. Quantitative changes of the constituents of the cytoplasma coming into being during the process of the keratinization appear to be similar in both forms of the lokalization investigated; 2. these changes seem to be opposite to the process observed during the differentiation of the normal epithelium; 3. by comparing stereological, histopathological and clinical data a new form of leukoplakia simplex can be distinguished i.e. the indirect form of the metaplasia of the squamous epithelium. 4 Method of the stereological morphometry seesm to be suitable for the description of characteristic features of the keratinization.

Cheek↗
PubMed1976

Evaluation of a 5-mum stainless steel filter as an intravenous inline filter or prefilter.

The suitability of a 5-mum stainless steel filter as an inline filter or a protective prefilter during simulated i.v. therapy was evaluated using flow rate measurements of two routinely used i.v. fluids and parenteral nutrition fluid. As an inline i.v. filter, the 5-mum stainless steel filter was capable of maintaining suitable flow rates. The addition of antibiotic additives decreased the flow rates slightly but not below the range required for i.v. therapy. Flow rate profiles, however, when compared to a 0.45-mum membrane filter suggest that antibiotic additives contain high numbers of particles in the less than 5-mum range. Consequently many of the particles, especially those in the less than 3-mum range will pass the 5-mum filter. As a protective prefilter, the 5-mum filter device in combination with a 0.45-mum membrane filter provided more uniform flow rates over longer periods of time when additives were employed. Using the aspiration device as a prefilter for adding antibiotics to the infusion fluid resulted in improved flow rates through a 0.45-mum membrane filter for lactated Ringer's containing cephalothin sodium, while for solutions containing ampicillin or oxytetracycline, prefilteration did not change the flow rate profiles.

Ampicillin↗
PubMed1975

Evaluation of a prototype air-venting inline intravenous filter set.

A prototype inline intravenous final filter with a large filtration area and an air-elimination feature was evaluated. Adequate and uniform flow rates were maintained with infusion solutions containing cephalothin and ampicillin, while with oxytetracycline, flow rates decreased significantly. Challenging the unit with air demonstrated the suitability of the air-elimination system. In a brief clinical trial on 53 patients, the unit appeared easy to use and gained the acceptance of nurses, pharmacists and physicians.

Ampicillin↗
PubMedDate not supplied

Does heart rate differentiate neurotic from normal people in a conditional reflex test?

This study is to compare heart reactivity between normals and anxiety neurotic patients. Five male and five female patients with anxiety neurosis and four male and five female normal persons were submitted to classic delayed conditional reflexes with different probabilities of reinforcement (shock), to a defensive instrumental conditional reflex, and to a neutral nonreinforced stimulus. The basal heart frequency was higher in neurotics and in women than in normals and men. The conditional stimulus (CS) associated with a shock generally produced a bradycardia in normal individuals and in neurotic men, but a tachycardia in neurotic women (effects most pronounced in cases with 100% shock probability). The instrumental CS caused a tachycardia in all of the groups, with highest values in neurotic women. The neutral stimulus produced bradycardia in all persons. The aftereffect of the light stimulus depended on whether a shock was administered and on the CS. The differences between neurotics and normals are explained as caused by the heightened excitatory level of the CNS of the neurotic group, produced by the unspecific activating effect of chronic anxiety, and differences of plastic processes in both groups, resulting in different effects of phasic anxiety on the heart. Complex inhibitory-excitatory interactions of the sympathetic and the vagal system underlying the heart rate changes may be assumed. Possible mechanisms leading to sex differences are discussed.

Adult↗
PubMedDate not supplied

Low doses of AMPA exert anticonvulsant effects on pentylenetetrazol-kindled seizures.

Excitatory amino acids (EAAs) are critically involved in the initiation and propagation of seizures. N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors appear to be of special interest in this regard. Besides receptor binding by antagonists, the function of glutamatergic synapses can be altered via autoreceptor-mediated mechanisms or by receptor desensitisation. Therefore, the effect of AMPA (1, 10 or 100 pmol per animal, intracerebroventricular injection) was tested on acutely induced pentylenetetrazol (PTZ) seizures. The lowest dose exerted clear anticonvulsant effects. Furthermore, 1 and 10 pmol AMPA were tested for their efficacy to suppress PTZ kindling. The lower dose reduced seizure severity significantly but 10 pmol AMPA was ineffective. In reaction to a test dose of PTZ, the kindled groups pretreated with AMPA reached seizure scores similar to saline-pretreated kindled rats, suggesting that the kindled state was reached. In a further experiment, we tested the effect of cyclothiazide (CYC, which blocks AMPA receptor desensitisation) on the 1 pmol AMPA-mediated anticonvulsant effect. The AMPA response was not altered. These results suggest that autoreceptor-mediated mechanisms rather than desensitisation might contribute to the anticonvulsant effect found.

Animals↗
PubMedDate not supplied

Enhancement of glutamate release by L-fucose changes effects of glutamate receptor antagonists on long-term potentiation in the rat hippocampus.

In previous studies L-fucose has been shown to facilitate long-term memory formation and to enhance and prolong long-term potentiation (LTP). To search for possible presynaptic or postsynaptic mechanisms that are affected by L-fucose, we examined the effect of L-fucose on (1) inhibition of LTP induction via glutamate receptors by antagonists, (2) paired-pulse facilitation, and (3) presynaptic transmitter release. Coapplication of 0.2 mM L-fucose with the competitive N-methyl-D-aspartate (NMDA) receptor antagonist, D-2-amino-5-phosphonovalerate (AP5), or coapplication of 0.2 mM L-fucose in the presence of an inhibitor for class I/II metabotropic glutamate receptors, (S)-alpha-methyl-4-carboxyphenylglycine (MCPG), reversed LTP blockade in the CA1-region of hippocampal slices. In contrast, L-fucose had no effect on the LTP blockade by the noncompetitive NMDA ion-channel blocker (5R,10S)-(+)-5-Methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5, 10-imine hydrogen maleate (MK-801). Paired-pulse facilitation, which is a primarily presynaptic phenomenon of short-term plasticity, was decreased in the presence of 0.2 mM L-fucose. Furthermore, L-fucose enhanced the K(+)-stimulated release of [(3)H]-D-aspartate from preloaded hippocampal slices in a concentration-dependent manner. These observations demonstrate an influence of L-fucose on transmitter release that in turn can increase transmitter availability at postsynaptic glutamate receptors. This effect of L-fucose may contribute to the LTP facilitation seen in vitro and in vivo as well as to improvement in memory formation.

2-Amino-5-phosphonovalerate↗
PubMedDate not supplied

Response to multimodal treatment in advanced neuroblastomas. Factors associated with complete remission induction, and factors associated with prolonged survival.

The influence of patient and treatment variables upon the probabilities of response to chemotherapy in advanced neuroblastomas was investigated in 71 children with stages III-IV disease treated in Denmark between 1965-1980. The therapeutic regimens consisted of various combinations of chemotherapeutic agents with or without surgical excision of the primary tumour and irradiation. Complete response (CR) was achieved by 75% of patients in stage III, and another 17% showed partial response. In stage IV 60% responded, 19% with CR. Relationships between patient and treatment variables and the probability of being alive in CR 22 weeks after initiation of the treatment were examined by logistic regression analysis. The probability of CR was not related to age at diagnosis, the addition of an anthracycline to the chemotherapeutic regimens, or to irradiation. Factors related to the maintenance of CR could not be statistically examined due to the small number of complete responders at 22 weeks. Only age below 2 years seems, however, to have positive impact on the response duration. The influence of patient characteristics was further suggested by the result of secondary treatment attempts. 42% of the patients selected for secondary treatment responded, and 17% achieved CR. 1/25 (4%) had survived disease-free for more than 8 years. Factors related to the duration of survival were subsequently examined in the 71 children using Cox's regression analysis. Only children below 2 years of age at diagnosis had survived for more than 8 years. Resection of the tumour at diagnosis, irradiation and the addition of an anthracycline appear not to influence the length of survival in this patient population.

Child↗
PubMedDate not supplied

Signs, symptoms, metastatic spread and metabolic behavior of neuroblastomas treated in Denmark during the period 1943-1980.

The clinical manifestations of 253 neuroblastoma cases in childhood, treated in Denmark from 1943 to 1980, were reviewed. Most striking was the vagueness of symptoms in the majority of patients, only a few of whom exhibited the symptoms strongly suggestive of a neuroblastoma (i.e. the Horner syndrome, the watery diarrhoea syndrome, the dancing eye syndrome). The vagueness of the symptoms might have led to fatal procrastination of the diagnosis. The diagnostic delay has, however, no independent prognostic significance for survival in our patients (p = 0.09). The maximal tumour spread was recorded for all 253 patients, and the distribution of metastases was in accordance with the "soil-seed" hypothesis. The tumour spreads with equal frequency by local growth, by lymphatic vessels to distant lymph nodes, and by blood to bone. Only in widely disseminated tumours are metastases to the lungs, the meninges, the brain, and the reproductive organs seen to occur. Eighty-five percent of the patients, for whom data were available, excreted VMA above the normal value for their age, and 43% excreted Norepinephrine + Epinephrine (N + E) above normal levels. The excretion of both VMA and N + E was significantly correlated to stage, and thus to prognosis. Neither the level of VMA excretion nor the level of N + E had any bearing on the survival when age and stage were adjusted for. Serial VMA and N + E determinations show that patients with normal values for these parameters had significantly better prognosis than patients with elevated values during the first, second, third and fourth trimesters after the initiation of treatment. Increasing values in the individual patient were associated with a poor prognosis. We found no correlation between the initial leucocyte count and survival when age and stage were adjusted for.

Age Factors↗