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Biomedical subjects

B Schildt

Publications and source records attributed to B Schildt.

15 recordsLinked to original sources
PubMed1978

Adsorption of insulin by infusion materials.

Doubt about insulin adsorption has been an obstacle to rational insulin treatment by i.v. infusion. The influence of several factors on adsorption was therefore studied using a radioimmunoassay technique to determine insulin levels. When 8 to 128 IU of insulin were added to 500- and 1,000-ml containers, a linear relationship was found between the amount added and the amount delivered to the patient, permitting the design of a practical nomogram. In other experiments, 32 IU of insulin was added to 1,000 ml containers. The type of insulin did not influence adsorption. Half of the 32 IU added to soda-glass and siliconized bottles were adsorbed, while plastic containers adsorbed less. Neither the type of infusion solution (except for 60% glucose), nor the type of infusion set infuenced adsorption. Human serum albumin prevented adsorption only incompletely.

Adsorption↗
PubMed1976

Stenosis following tracheostomy. A quantitative study of long term results.

Seventy out of the 320 patients treated with tracheostomy and respiratory care in an intensive care unit, were included in a follow-up study. A variety of surgical (38) and medical (32) conditions had prompted IPPV for 1-59 days; 33 had had primary and 37 secondary tracheostomies. The final study included an interview, physical examination, radiographic examination and spirometry. Using radiographic measures, the area of stenosis was calculated as well as the pressure drop across the stenosis at various flow rates. The methods of calculation were tested in one patient and compared with the actual tracheal pressure and gas flow recordings. Lateral stenosis was found in 69 and frontal stenosis in 25 patients, the length being 0-2-5-0 cm. The stenosis was situated at the level of the stoma in 59, at the cuff in 6, and at both sites in 2; in 2 the level could not be determined accurately. The mean area of normal trachea was 2-8+/-0-8 cm2 in females and 3-7+/-0-7 cm2 in males, while the stenotic area ranged from 0-86 to 4-54 cm2. A stenosis of potential functional significance was found in 8 patients (area less than 1-5 cm2). The stenotic area correlated well with the pressure drop across the stenosis and better than with the stenosis percentage (1-74%). The predicted pressure falls over the stenosis at different flow rates were in excellent agreement with those measured in one patient. Spirometry was unsuitable for detecting the stenosis. Poor correlation were found between the degree of tracheal stenosis and chronic respiratory disease, smoking, age, interval between intubation and tracheostomy, or duration of IPPV. Dysponea during moderate exercise was present in all patients who had a pronounced stenosis.

Female↗
PubMed1976

Preparation of cross-linked human serum albumin labelled with 125I for studies of reticuloendothelial system function.

A method is described to prepare a new test substance for reticuloendothelial system (RES) function studies. Glutaraldehyde was used for the cross-linking of human serum albumin. The polymeric product was fractionated by repeated chromatography on Sepharose 6B. Cross-linked material with a particle size of approximately 18 nm, as evidenced by electron microscopy, was pooled and labelled with 125I. The surface charge of the albumin polymers, determined by agarose gel electrophoresis, was not significantly changed compared with that of the original albumin monomer. Cross-linking takes place almost entirely between the epsilon-amino groups of lysine in the albumin molecules, as confirmed by amino acid analysis. Preliminary biological tests on mice indicate that the cross-linked polymers are phagocytosed mainly by RE cells of the liver and spleen. The disappearance rate was similar to that of other RE test substances. Intravenous administration of more than 50 times the usual dose caused no deaths, indicating a very low toxicity. Trace amounts of glutaraldehyde were not detectable by gas chromatography. Judging from these experiments, this new preparation of cross-linked albumin fulfils many of the criteria stated for an ideal RES test substance.

Animals↗
PubMed1976

Effect of low-dose heparin on the phagocytic and catabolic function in the reticulo-endothelial system in man during surgery.

The effect of subcutaneous low-dose heparin prophylaxis on the phagocytic and catabolic functions of the reticuloendothelial system (RES) was studied in 10 patients undergoing elective cholecystectomy. The patients were divided into two groups; 5 patients receiving 5 000 units of heparin preoperatively and every 12 hours following the operation and 5 patients given saline at the corresponding time. Each patient served as his own control, when the RES function was tested twice with microaggregated human serum albumin labelled with 125I as a test substance. There was an enhanced phagocytic activity and a correspondingly raised catabolic activity of the RES in patients treated with heparin. The reasons for this are discussed. The results indicate that heparin in low doses has a favourable effect on the RES.

Heparin↗
PubMed1975

Tissue PO2 measured in man by an implanted latex rubber tube.

A latex rubber tube easily permeable to O2 was implanted in a triceps muscle of six volunteers. Seven days later, PO2 in muscle tissue (PtO2) was measured repeatedly by filling the tube with saline. After a 2-minute equilibration, the saline was sampled in a glass capillary and its PO2 measured by polarographic technique. PaO2 and venous oxygen tension (PvO2) were measured simultaneously. Measurements were performed under four conditions: (1) air breathing, (2) breathing 100% O2, (3) breathing 14% O2, and (4) 50 Warm exercise. During (1) breathing air PaO2 was on an average 90 mmHg, PvO2 36 MMHg and PtO2 40 mmHg. During (2) PaO2 reached 570 mmHg in 2 min, PvO2 rose slightly and PtO2 increased to 80-90 mmHg in 30-40 min. During (3) PaO2 fell rapidly to 45 mmHg and PtO2 decreased from 40 to 30 mmHg in 8 min. During (4) PaO2 did not change, PvO2 decreased slightly and PtO2 fell to approximately 30 mmHg within 2-4 min. The interindividual scatter was of equal magnitude in tissue and blood. A PtO2 higher than PvO2 during oxygen breathing and less than PvO2 during hypoxia and physical exercise is explained by the existence of oxygen gradients in the extravascular space. The present technique proved to be simple despite a 1-week delay before measurements. There were no complications, and no discomfort was complained of. Thus, the latex rubber tube seems suitable for clinical use.

Adult↗
PubMed1975

Cardiac output determinations with ear piece densitometry.

The results of cardiac output determinations by a dye dilution technique were compared using (a) a dichromatic earpiece which was calibrated as a flow-through cuvette, but also permitted automatic computing by virtue of a pressure capsule, and (b) an ordinary flow-through densitometer. Eleven subjects, some with cardio-pulmonary disease, were investigated. Cardiac outputs were systematically overestimated when automatically computed. The results obtained by manual calculation with the ear-piece corresponded more nearly with those derived from the flow-through cuvette, but still with a deviation from the identity line and with a residual standard deviation of 0.8 l/min. Double determinations had a residual standard deviation of 0.7 l/min. Despite its ease of handling, an earpiece densitometer seems to be too unreliable to be suitable for routine use.

Adult↗
PubMed1975

Plasma substitute induced impairment of the reticuloendothelial system function.

Currently used plasma substitutes are large colloids and are partly engulfed by reticuloendothelial (RE) cells. This study was designed to investigate the magnitude and duration of the possible RES dysfunction induced by plasma substitutes. The following substances were studied in both normal and burned (LD-10) CBA mice: allogen albumin 3%, and commercial preparations of dextran 40, dextran 70, hydroxyethyl starch, gelatin and PVP. Infusion volume was 20 ml/kg and i.v. infusion time 1 hour. Animals given allogen plasma served as controls. One, 3 and 6 hours after the i.v. injection of 51-Cr-rabbit RBC, we determined the disappearance rate, and uptake and distribution of the 51-Cr-RBC in the main RES organs (liver, spleen and lungs). In normal mice the disappearance rate was significantly decreased one and three hours post infusion, while it was decreased even after 6 hours in burned mice. Groups given albumin or plasma stayed close to non-infused animals. In order to clarify the physiologic significance of these findings we used another test substance known to be handled by the RES. Salmonella enteritidis endotoxin was tested with regard both to toxicity and rate of elimination. The toxicity, after i.p. injection, was significantly intensified both one and 3 hours post-infusion in normal mice. In burned mice toxicity became even more intense. The ability to eliminate 51-Cr-labelled endotoxin was significantly decreased following infusion in both normal and burned mice, one as well as three hours later. The in vitro liver phagocytosis was tested utilizing the liver slice technique. Standardized slices were incubated in Krebs-Ringer buffer together with 125-I-HSA aggregates as RES test substance with and without plasma from mice given plasma substitute infusions. Allogen plasma enhanced the phagocytic uptake (four times), while post-infusion plasma did not. It is concluded from these experiments, utilizing two different RES test substances in both normal and hypovolemic animals, that the plasma expanders tested do impair RES phagocytosis. The mechanism seems to be an interaction with phagocytosis-promoting plasma factors. Even though this impairment is temporary, it may jeopardize such important RES functions as elimination of microorganisms, toxins, cell debris and tumour cells, or spoil the afferent limb of the immune response to many antigens.

Animals↗
PubMed1975

Bilateral chylothorax - complication in malignancy.

Bilateral chylothorax is a rare condition caused by traumas and disorders with perforation or destruction of main lymphatics in the thorax leading to lymph leakage. Two patients with bilateral chylothorax are presented one of whom was successfully operated on. Etiology, diagnostics and therapy of this condition are discussed.

Aged↗