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Biomedical subjects

H Haindl

Publications and source records attributed to H Haindl.

At least 19 recordsLinked to original sources
PubMed2006

[Microcatheter in neuroradiology].

The application of neuroradiologic microcatheters may be beneficial for the patient as well as preoperative intervention or as sole therapeutical procedure. However, it is associated with a relatively high procedural risk, which is also supported by critical dimensions of the microcatheter. It is regrettable, that to some extent, the performance of manufacturers of microcatheters stay below today's technical possibilities. Conducted investigations of ruptured catheters could not prove, that ruptures could have been avoided by using better manufacturing techniques, however, it should be expected, that manufacturers ensure the highest possible technical performance. Attempts to re-process those products, because of their high price show, that not all technical problems and resulting risks are well understood by all parties concerned. The demand for re-processing is not congruous with current medical responsibility.

Catheterization↗
PubMed1996

Life-span indicator for resterilizable plastic products.

Disposable medical products have obvious advantages for users, in particular, assured sterility. Yet, one-time use creates large amounts of waste that cannot easily be reprocessed. Despite this, resterilizable products are not common, principally because of problems in monitoring the level of resterilization. This article suggests a solution in the form of an indicator that changes colour according to the number of sterilization cycles it undergoes.

Durable Medical Equipment↗
PubMed1995

[A new port catheter system of aluminum oxide ceramics].

Implantable port catheter systems are becoming increasingly important, as they often permit out-patient treatment for many indications that would otherwise require hospitalization. Moreover, they also increase the safety/reliability of infusion therapy in critical inpatients. For a variety of reasons, the materials used so far, i.e. steel, titanium and various plastics have not been completely satisfactory. The main disadvantage of metallic systems is the formation of artefacts in tomographic images, while the shortcomings of plastics are mechanical, e.g. chip formation and early membrane failure. Against this background, a port catheter system made of alumina ceramic, which is largely free of the disadvantages of the other materials, was developed. The expected advantages in terms of complication rate and radiological artefacts, were fully confirmed by the evaluation of 160 monitored patients.

Aluminum Oxide↗
PubMed1990

[The safety of disposable medical products].

Medical disposables are a very heterogenous description of goods. A coherent safety philosophy exists for production conditions, but not for the product itself. Influencing factors on product safety are demonstrated and illustrated with examples.

Catheters, Indwelling↗
PubMed1990

[The problems of parallel infusion].

The parallel infusion of gravity and pump systems on the same vascular access bears dangers for the patient. Occlusions of the vascular access will not be recognized by pump alarm and bolus applications of accumulated drugs can occur. All means to avoid this problem are up to now not satisfying. Especially the use of one-way-valves is not a solution for every case.

Equipment Design↗
PubMed1990

[A new technic for interpleural blockade].

A new method for pleural block is presented. As the loss-of-resistance technique is not a useful approach for identification of the pleural cavity, alternative concepts, such as low-friction syringe-piston movement and infusion techniques have been developed for identification of the pleural cavity for catheter insertion. Both methods have the disadvantage that they involve a risk of pneumothorax during the insertion of the catheter, because it is necessary to disconnect the Tuohy needle from the syringe or infusion apparatus at the moment of catheter insertion. At this time there will be a direct communication between the pleural cavity and outside. A new technique has now been developed: this involves a latex balloon that collapses under the negative pressure of the pleural cavity. With this new technique it is possible to insert the catheter without disconnection. Furthermore, the identification is more sensitive than with the other techniques, so that the risk of pneumothorax is minimized. The technique has been applied in 71 cases with no technique-related complications.

Bupivacaine↗
PubMed1989

[The injection abscess--a sequela of unsuitable cannulas?].

Skin-cylinders punched out by hypodermic needles, are discussed as an influencing factor in abscess forming after injection. Up to now these skin-cylinders are regarded as unavoidable. The authors show, that with different types of hypodermic needles the frequency of skin-cylinders widely differs. They resume, that the frequency of post injection abscesses could be reduced by the use of better suitable needles.

Abscess↗
PubMed1988

[An atraumatic needle for the puncture of ports and pumps].

Huber-point needles have been found to induce substantial coring during puncture of ports or pumps, which may lead to leakage or obturation of these devices. Therefore, different types of cannulas were tested in order to evaluate their applicability for this purpose. Pencil-point needles led to increased pain during puncture and thus seemed unsuitable. A newly developed port-cannula bent inwards within the length of the bevel ("protected bevel") and proved to be definitely noncoring during electron microscopy. Consequently the force required to introduce this needle was reduced by 50% in comparison with the Huber-type needle. In addition, this cannula allowed up to 3000 punctures of one port without leakage and, thus, correspondingly therefore relevantly increased the durability of this device.

Catheters, Indwelling↗
PubMed1985

Growth and function of thirty-four human benign and malignant thyroid xenografts in untreated nude mice.

Tissue was taken from 16 patients with benign thyroid lesions (10 nontoxic nodular colloid goiter, two follicular adenoma, one autonomous adenoma, one iodine-induced thyrotoxicosis, 2 Graves' disease) and 18 patients with malignant thyroid tumors [seven papillary, five follicular, five undifferentiated (anaplastic), and one medullalry carcinoma] and was xenotransplanted into the flanks of 124 syngeneic female BALB/c-nu/nu mice 6 weeks of age. Subsequently, without any further treatment, serum levels of thyroglobulin (TG), T3, T4, and thyroid-stimulating hormone were determined by radioimmunoassay at 4 or 5 weeks posttransplantation and at the end of the experimental time period of 4 months. All animals were autopsied. The grafts were examined by light microscopy and TG immunohistochemistry. Morphologically, the grafts of benign and malignant thyroid tumors showed features overall identical to the original tissue. Conversely, nontoxic nodular colloid goiter and Graves' disease grafts revealed a transformation to normofollicular structures. All benign thyroid grafts showed a stationary growth, as did most differentiated thyroid carcinomas. Tumor take rates in differentiated and in medullary carcinoma were 15%, and in undifferentiated carcinomas, 100%. In the cancer grafts, a correlation between resting phase (period until progressive tumor growth) and survival time of the corresponding patients was disclosed. All patients whose tumors were not taken by nude mice are still alive and show no signs of progressive tumor growth at 9 to 34 months after surgery. All but one patient with tumors revealing positive tumor take died within 3 months (resting phase, 3 weeks) or one year (resting phase, 7 to 14 weeks) after surgery. Integrity of hormonal function in benign and malignant xenografts at 4 months posttransplantation could be shown by significantly higher T3 and T4 serum concentrations in animals with benign thyroid tissues (T3, 1.69 +/- 0.13 nmol/liter; T4, 45.69 +/- 2.09 nmol/liter; S.E.) as compared to controls without grafted tissue [T3, 1.29 +/- 0.10 nmol/liter (p less than 0.05); T4, 33.39 +/- 2.71 nmol/liter (p less than 0.05)] and by increased TG serum concentrations in animals receiving benign (TG, 2.70 +/- 1.39 ng/ml) or malignant (e.g., TG in follicular carcinoma, 34.44 +/- 13.83 ng/ml; controls, 0.30 +/- 0.02 ng/ml) thyroid tissue. Thus, we conclude that benign and malignant thyroid xenografts in the nude mouse maintain full morphological and, regarding T3, T4, and TG serum levels, functional integrity for at least 4 months after transplantation.

Animals↗
PubMed1982

Evaluation of EMIT adapted to the (Cobas) Bio centrifugal analyzer.

EMIT assays for the determination of phenytoin, methotrexate, disopyramide, digoxin and thyroxine were adapted to the Cobas Bio centrifugal analyzer and compared with the corresponding laboratory routine procedures. Evaluation of the data from the Cobas Bio by 5 different mathematical models showed that the four-parameter logit model correlated best with the comparison procedures and the originally recommended calculation model for the reagent lots used in our study. The precision of the EMIT phenytoin, methotrexate and disopyramide assays was in most cases very good (between-days coefficient) of variation 1.6-7.5%). A lower precision was observed with the EMIT digoxin assay (between-days coefficients of variation 9.2-16.8%) and at low concentrations also with the EMIT thyroxine assay (3.1-21.4%). Calibration curves of the EMIT phenytoin, methotrexate assays were stable for at least one hour. The results from the determination of phenytoin, methotrexate and disopyramide in patient samples by use of the Cobas Bio were in good agreement with those values obtained with the EMIT/LAB. The data determined with the EMIT digoxin assay adapted to the Cobas Bio correlated better with those of a radioimmunoassay than the values measured with the EMIT/LAB system. The results of thyroxin determinations with EMIT by use of the Cobas Bio and the original procedure with an ABA-100 were in good agreement and on average about 12% lower than those measured by radioimmunoassay. The Cobas Bio allows rapid determination with EMIT and a reduction in direct costs of up to 85%.

Centrifugation↗
PubMed1981

Determination of triiodothyronine in serum by enzyme- and radioimmunoassay: a comparative study.

An evaluation of a heterogeneous enzyme immunoassay for determination of triiodothyronine in serum (Enzymun-Test T3, Boehringer Mannheim) is presented. The enzyme immunoassay was compared with the laboratory routine radioimmunoassay. The precision of both assays was satisfactory at triiodothyronine concentrations between 1.0 and 8.0 nmol/l (coefficients of variation from day to day less than or equal to 10%). Average recoveries of triiodothyronine in pool sera ranged with the Enzymun-Test T3 from 96--104% and with the radioimmunoassay from 88--111%. A comparison of the results obtained by Enzymun-Test T3 and the radioimmunoassay in a series of 103 patients showed a good correlation between both methods. L-thyroxine did not cause a relevant cross-reaction in the enzyme immunoassay. About 20 unknown samples can be analyzed in triplicate by Enzymun-Test T3 within 260 minutes.

Cross Reactions↗
PubMed1981

[Determination of triiodothyronine in serum with a heterologous enzyme immunoassay: results of a group survey].

This paper summarises the results of the evaluation of a heterologous enzyme immunoassay in antibody coated tubes for the determination of triiodothyronine (T3) by a group of 11 laboratories. The assay procedure is analogous to an established heterologous thyroxine enzyme immunoassay. The evaluation demonstrated that 1. the specificity of the assay and its analytical range between 0.46 and 9.2 nmol/l meet diagnostic requirements, 2. the intra- and interassay precision was in accordance with that commonly found in radio immunoassays, 3. the recovery of added T3 was between 90 and 103%, 4. the results agreed well with those of self-established radio immunoassays and were comparable with commercial RIA kits, 5. there was no interference by hyperbilirubinaemia or by high concentrations of bile acids, but interference can occur in very haemolytic and lipaemic samples. The great advantage of T3 enzyme immunoassays lies in the absence of restrictions and any authorization needed for working with radioactive substances.

Evaluation Studies as Topic↗