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Biomedical subjects

N Haas

Publications and source records attributed to N Haas.

At least 181 records · Page 10Linked to original sources
PubMed1985

[Progress in external fixation].

The monofixateur opens up avenues in external skeleton fixation. Proceeding from Lambotte's groundwork and from the given anatomical conditions and biomechanical requirements, a system has been developed that ensures maximum effectiveness with a minimum of mechanical means and operative procedure. Of particular importance is the dual-application feature of the monofixateur system: it is equally indicated for static as well as dynamic fixation, and is quickly and easily adapted from one function to the other at any time as called for by the treatment process. This system provides for dynamic function when applied without fixation clamping jaws on one of the major bone fragments. It allows for functional axial compression to be exerted through muscle contraction and pressure, while simultaneously excluding the possibility of bending and rotation, thus effectively promoting the healing process. The monofixateur is indicated for treatment of closed, open and infected fractures, pseudarthrosis, osteotomy adaption, arthrodesis and joint transfixations. In brief, the advantages of external fixation by the monofixateur may be summarized as follows: Simple mechanical design affording precise function. High stability with small number of fixation components. Unilateral assembly of device in position biomechanically favorable. Static or dynamic fixation. Little patient impairment.

Femoral Fractures↗
PubMed1984

Reduced permeation of 14C-sucrose, 3H-mannitol and 3H-inulin across blood-brain barrier in nephrectomized rats.

Experiments were carried out to determine if changes in the concentration-time profile of a blood-borne radiotracer such as 14C-sucrose would spuriously alter measurements of its permeation across the blood-brain barrier (permeability-area product, PA) based on a 2-compartment (plasma/brain) simple diffusion model. Anesthetized rats which were bilaterally nephrectomized and given a standard intravenous bolus injection of 14C-sucrose, 3H-mannitol or 3H-inulin exhibited an elevated plasma tracer concentration compared to control animals. However, tracer concentration measured in brain parenchyma after 30 min was not proportionally elevated, and PA calculated from the ratio, parenchymal tracer concentration: plasma concentration-time integral, was significantly reduced below control values. In control rats, distortion and elevation of the plasma 14C-sucrose profile by continuous intravenous infusion did not result in lowered PA values. This suggested that the lowering of PA by nephrectomy reflected reduced cerebrovascular permeability or area or other cerebral influence rather than a deficiency in the 2-compartment model for PA measurement.

Animals↗
PubMed1984

Identification of the bacteriophage T4 unf ( = alc) gene product, a protein involved in the shutoff of host transcription.

The introduction of plasmid pR386 into E. coli cells renders them restrictive to the growth of phage T4 unf ( = alc) mutants. This system has been used to isolate Unf+ revertants, which, along with the mutant parental strains, have been used to identify the unf gene product by two-dimensional gel electrophoresis. Synthesis of the unf gene product, a polypeptide of just over 18,000 daltons in size, begins within 1 min after infection and terminates at about 12 min after infection at 30 degrees. Gene dosage experiments suggest that the unf protein functions catalytically.

DNA, Bacterial↗
PubMed1984

[Medullary reaming in chronic osteomyelitis of the stable femur and tibia shaft].

Ten patients with chronic osteomyelitis of the femur or tibia shaft without bone instability were operated by intramedullary reaming. All patients but one had previous surgery, up to 12 operations with the average duration of the disease 10.5 years. After intramedullary reaming all patients received systemic antibiotics for 8 days and in 6 cases the intramedullary cannal was filled with gentamicin-PMMA chains which were removed in local anaesthesia 10 days after surgery. Eight patients who had severe pain at rest were promptly relieved by the operation. In 3 cases of chronic fistulation only one exacerbation was seen. This was because of insufficient reaming, the patient was subsequently reoperated with reaming from a distal approach. During the observation periode from the month 12 to 32 in no case was there a recurrence of pain or infection.

Adult↗
PubMed1983

A modified method for measurement of radiotracer permeation across the rat blood--brain barrier: the problem of correcting brain uptake for intravascular tracer.

A modified technique to assess integrity of the rat blood--brain barrier is described in which a poorly permeating radiotracer is injected intravenously and its net permeation across the cerebral vasculature in 30 min is related to its time-averaged level in the circulation. At the termination of experiments, direct carotid arterial perfusion clears blood from brain in 30 s and permits measurement of the tracer level in brain parenchyma without correction for intravascular tracer. Constant-rate withdrawal of a single arterial blood sample throughout the period of tracer circulation replaces the need for repeated blood sampling and graph plotting to determine the time-integrated plasma tracer level. During the first 2-3 min following intravenous injection of [3H]mannitol or [14C]sucrose, permeation across the barrier occurred at a rate substantially greater than that measured for a 30 min circulation time. The relatively rapid uptake of these tracers into brain during the first few minutes after injection would explain in part why estimates of regional blood volume, calculated from ratios of brain vs blood tracer concentration after short circulation times, were much higher than values determined using [51Cr]erythrocytes.

Animals↗
PubMed1982

[Acute, toxic, reversible hair loss through drain and sanitary cleansing vapors containing sodiumhypochloride and sodiumhydroxide].

Exposition to drain and sanitary cleansing vapors containing sodiumhypochloride and sodiumhydroxide provoked acute, reversible toxic alopecia. Trichograms of this depilatory type of alopecia showed that signs of hair dystrophy and loss of the hair sheath. Histological examination of skin and hair showed changes in hair structures and discrete lymphocytic infiltration. The prerequisite for this effect was the improper use of cleansing agents and the relative conditions during use which led to the intense exposition of the scalp to sodiumhypochloride vapor. A possible chemical reaction between cleansing agent and dirt may have been responsible, just as the condition of the scalp and hair e.g. increased transpiration, hydration may have led the way to hair loss. Acute hair loss occurred in the scalp and beard region following the use of cleansing agents; additional genital hair loss arose after sodiumhydroxide use. This condition persisted for 4 weeks. Body and scalp hair was completely restored after 1 year.

Alopecia↗