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Biomedical subjects

C J Lamm

Publications and source records attributed to C J Lamm.

10 recordsLinked to original sources
PubMed1991

Quantification of Birbeck's granules in human Langerhans' cells.

A proper understanding of the function of Birbeck's granules requires that they should be counted under various conditions. We now present a simple quantification method which does not depend on specific assumptions concerning size, shape or location of the particles counted and can, moreover, be applied for counting other subcellular structures as well. A population of 69 serially sectioned human Langerhans' cells had an average of 290 granules and no cell contained fewer than 96 granules, indicating that as they degrade, granules are continuously formed. Suprabasal Langerhans' cells contained significantly more granules than did the basal cells.

Biopsy↗
PubMed1983

Automated rhinomanometry.

In order to facilitate measurements and calculations in rhinomanometry a microprocessor is used. Pressure and flow signals, obtained from microtransducers, are automatically calibrated by drawing known volumes of air through a standardized test-nose, while the signals are read by the computer. When the patient is connected, the pressure-flow curves are displayed on a screen. At adequate breathing, the computer reads the pressure and flow 200 times per second for a few breaths. It performs all calculations and presents data describing the pressure-flow relationship, e.g. in terms of the resistance, where the curve crosses a circle with a certain radius in a polar coordinate system. Automatically calculated data were compared to manually derived ones in six healthy subjects and twenty patients with symptoms of nasal obstruction. There was a close correlation between the two sets of data. It is concluded that the described automated rhinomanometer facilitates the rhinomanometric procedure and gives accurate data on nasal airway resistance.

Airway Resistance↗
PubMed1982

Tracheal relaxant and cardiostimulant actions of xanthines can be differentiated from diuretic and CNS-stimulant effects. Role of adenosine antagonism?

Theophylline (1, 3-dimethylxanthine) and enprofylline (3-propylxanthine) have been examined for effects in the rat. Enprofylline was 3.8 times as potent as theophylline as a tracheal relaxant in vitro, and 1.3 times as potent as theophylline to increase the rate of isolated perfused hearts. An oral dose (5 mg/kg) of enprofylline to rats was almost completely recovered in the urine as unchanged drug, showing that this xanthine is well absorbed and negligibly metabolised. Theophylline (10 and 30 mg/kg p.o.) significantly and dose-dependently increased locomotor activity in rats whereas the same doses of enprofylline were without effect on behaviour. Theophylline ( 5-20 mg/kg p.o.) produced significant and dose-dependent natriuretic and volume diuretic effect with little augmentation of potassium excretion. Enprofylline up to 10 mg/kg was without diuretic effects. At the large dose of 20 mg/kg enprofylline decreased sodium excretion and produced some volume diuresis. It is suggested that lack of diuretic and CNS-stimulant behavioural effects by enprofylline is due to its low ability to antagonise adenosine receptor stimulation. Pharmacodynamic differences between enprofylline and the potent adenosine antagonist theophylline may indicate a functional importance of endogenous adenosine.

Adenosine↗
PubMed1981

Reduction of metacholine-induced nasal secretion by treatment with a new topical steroid in perennial non-allergic rhinitis.

The value of three objective tests of the nasal mucosa in 22 patients with perennial non-allergic rhinitis treated with a topical corticosteroid has been investigated. Placebo and three different dosages of a new steroid, budesonide, were administered intranasally using a double-blind, cross-over technique. Nasal airway resistance was not reduced by the steroid treatment as compared with the placebo treatment. Eosinophilia in nasal smears was reduced by budesonide. However, the value of this test was decreased by the fact that eosinophilia was found in less than 50% of the patients at the beginning of the trial. Metacholine-induced nasal secretion was significantly reduced by the budesonide treatment. Symptom scores for nasal obstruction, secretion and sneezing attacks were also significantly reduced by the steroid.

Administration, Intranasal↗
PubMed1980

Masticatory efficiency.

A method for measuring masticatory efficiency is described as well as a mathematical formula expressing the masticatory efficiency as an index. A silicone compound was used as test material. The masticatory efficiency index was calculated as the mean of the best four out of five consecutive measurements of masticatory efficiency calculated from a specially designed formula.

Chemical Phenomena↗
PubMed1980

The adrenoceptor blocking properties of the new beta 2-selective antagonist, IPS 339 on tracheal smooth muscle and on slow contracting skeletal muscle.

The beta-adrenoceptor blocking properties of IPS 339 and propranolol were studied on isolated preparations of trachea and of the slow-contracting soleus muscle from the guinea-pig. Both compounds antagonized the relaxation of the trachea and the depression of subtetanic contractions of the soleus produced by the beta2-selective agonist, terbutaline. On the soleus muscle the pA2-values for IPS 339 and propranolol were similar and close to those obtained for propranolol on the trachea. However, on the trachea the slope of the Schildplot for IPS 339 against terbutaline became less than one and a reliable pA2-value could not be calculated.

Adrenergic beta-Antagonists↗
PubMed1979

A universal way to evaluate the curve in rhinomanometry.

A new way to evaluate the curve of nasal airway resistance has been developed. With polar coordinates, all curves can be described. Also, tightly closed or wide open noses can be compared with angles. The method is of value in clinical as well as in scientific work, especially when dealing with statistics.

Airway Resistance↗
PubMed1976

A model of the breakdown and removal of the chromatin components during Feulgen acid hydrolysis.

A stochastic model of Feulgen hydrolysis is proposed. The model, constructed so as to embody the main features of chromatin structure, is simple enough to allow the calculation of extraction rates. Extraction rate curves generated by the model are compared with experimental curves obtained under various conditions (different fixatives and hydrolysis solutions). A good correspondence is found between the experiments and the predictions of the model.

Animals↗
PubMedDate not supplied

Rhinomanometry. II. A system for numerical description of nasal airway resistance.

Various ways of expressing rhinomanometric results have been an obstacle for exchange of information. A method that could be generally accepted must: 1) easily give the clinician an informative figure describing the nasal airway patency in all cases: 2) provide a basis for statistical evaluation: and 3) allow a numerical description of the whole pressure-flow (P-V) curve. In our system P-V curves are traced X-Y wise and described with polar coordinates (angles and radii). The system can be applied in three modes. The 'clinical' mode describes resistance at a standardized condition defined by a circle of the pressure-flow diagram. Data can be read direct from the pressure-flow curve. The 'statistical' mode yields nearly normal distribution. The 'mathematical' mode describes the whole pressure-flow curve, in terms of changing angle with radius. This mode brings about good and stable curve-fitting. Calculation of properties of the total nose from data of each cavity can be done with a pocket calculator.

Adolescent↗