Search PubMed⌕ Search

Biomedical subjects

H Kern

Publications and source records attributed to H Kern.

At least 73 records · Page 4Linked to original sources
PubMed1987

Rapid analytical and preparative isolation of functional endosomes by free flow electrophoresis.

Endosomes are prelysosomal organelles that serve as an intracellular site for the sorting, distribution, and processing of receptors, ligands, fluid phase components, and membrane proteins internalized by endocytosis. Whereas the overall functions of endosomes are increasingly understood, little is known about endosome structure, composition, or biogenesis. In this paper, we describe a rapid procedure that permits analytical and preparative isolation of endosomes from a variety of tissue culture cells. The procedure relies on a combination of density gradient centrifugation and free flow electrophoresis. It yields a fraction of highly purified, functionally intact organelles. As markers for endosomes in Chinese hamster ovary cells, we used endocytosed horseradish peroxidase, FITC-conjugated dextran, and [35S]methionine-labeled Semliki Forest virus. Total postnuclear supernatants, crude microsomal pellets, or partially purified Golgi fractions were subjected to free flow electrophoresis. Endosomes and lysosomes migrated together as a single anodally deflected peak separated from most other organelles (plasma membrane, mitochondria, endoplasmic reticulum, and Golgi). The endosomes and lysosomes were then resolved by centrifugation in Percoll density gradients. Endosomes prepared in this way were enriched up to 70-fold relative to the initial homogenate and were still capable of ATP-dependent acidification. By electron microscopy, the isolated organelles were found to consist of electron lucent vacuoles and tubules, many of which could be shown to contain an endocytic tracer (e.g., horseradish peroxidase). SDS PAGE analysis of integral and peripheral membrane proteins (separated from each other by condensation in Triton X-114) revealed a unique and restricted subset of proteins when compared with lysosomes, the unshifted free flow electrophoresis peak, and total cell protein. Altogether, the purification procedure takes 5-6 h and yields amounts of endosomes (150-200 micrograms protein) sufficient for biochemical, immunological, and functional analysis.

Animals↗
PubMed1986

[Micromethod for the detection of erythrocyte antigens in blood stains].

A micromethod was developed to allow the analysis of blood stains of minor size by the absorption elution technique. The individual absorption, washing, and elution steps were carried out in Beckman tubes containing 5 microliter antiserum. The final agglutination reaction was read through the inverted microscope in microtest plates regularly used for HLA typing. For this final reaction, 2-4 microliter eluate was incubated with 2,000 red blood cells suspended in 1 microliter saline and supplement. For the purpose of standardization, the intensity of agglutination in the microtest plate had to be defined. In comparison to the standard method (tube test and centrifugation), the proposed method proved to be slightly more sensitive with regard to the Rhesus and slightly less sensitive with regard to the AB0 system. With the proposed method very small traces could be successfully analyzed. Thus, two cotton threads 1 mm in length were sufficient for testing antigens A and B, and two cotton threads 2.5 mm in length were enough to detect an Rh antigen.

ABO Blood-Group System↗
PubMed1986

Effects of oral agents on pancreatic duct permeability. A model of acute alcoholic pancreatitis.

The main pancreatic duct can be made permeable to molecules of up to 20,000 daltons by oral pretreatment with aspirin and ethanol. Because pancreatic enzymes have similar molecular weights, we hypothesized that activated pancreatic enzymes would leak from a permeable duct and produce pancreatitis. Four groups of cats were pretreated with either milk, aspirin, ethanol, or aspirin and ethanol for 48 hr. Then pancreatic juice (either activated by enterokinase or nonactivated) was perfused along the duct from tail to duodenum. Twenty-four hours later the animals were examined. Animals pretreated with aspirin, ethanol, or both, and in which ducts were perfused with activated juice, developed acute edematous pancreatitis. Animals that had perfusion with nonactivated enzymes had pancreases indistinguishable from control animals. Morphological studies on ductal permeability in animals pretreated with ethanol and aspirin showed electron-dense material (believed to be dextran) between the basal plasma membrane and basal lamina, and in the basal intercellular space.

Acute Disease↗
PubMed1986

Lipase synthesis in the rat pancreas is regulated by secretin.

Conscious rats were infused with optimal doses of secretin (16 clinical units [CU]/kg/h), cerulein (0.25 microgram/kg/h), and both for varying periods of time over 24 h. The presence of zymogen granules in acinar cells and the tissue content of enzymes showed progressive decreases over 3 and 12 h for cerulein and secretin stimulation, respectively. Stimulation with either hormone resulted in a two-fold increase in protein synthesis at 6 and 12 h. Kinetically, the increases observed in protein synthesis were not directly coupled to the observed decreases in tissue content of enzymes. Cerulein stimulation selectively increased the synthesis of anionic trypsinogen forms 1 and 2 and chymotrypsinogen forms 1 (anionic) and 2 (cationic) and decreased the synthesis of amylase. Secretin stimulation selectively promoted the synthesis of lipase and proelastase 2. Lipase synthesis was increased 2.8-, 5.8-, and 4.8-fold at 6, 12, and 24 h, respectively. Proelastase 2 synthesis was increased 2.3-, 3.0-, and 3.4-fold at the same time points. In combination, secretin and cerulein stimulation resulted largely in competitive effects, suggesting that the two hormones exert effects on protein synthesis through different mechanisms. The findings suggest that the anticoordinate changes observed in the synthesis of functional groups of pancreatic enzymes by nutritional substrates in the diet are modulated by specific hormones. Synthesis of the majority of protease zymogens but not cationic trypsinogen or proelastase 2 is modulated by cholecystokinin and its peptide analogs. In contrast, the synthesis of pancreatic lipase and proelastase 2 is regulated by secretin. The findings indicate for the first time that secretin regulates the synthesis of specific proteins in the exocrine pancreas.

Animals↗
PubMed1985

Multiple-level caerulein control of the gene expression of secretory proteins in the rat pancreas.

Continuous intravenous infusion of caerulein (0.25 micrograms X kg-1 X h-1) has recently been reported [Schick, J., Kern, H. & Scheele, G. (1984) J. Cell Biol. 99, 1569-1574] to enhance significantly the synthesis of both trypsinogen and chymotrypsinogen and to decrease that of amylase in the rat pancreas. With a view to achieving a better understanding of the mechanisms underlying caerulein modulation of pancreatic gene expression, the relative levels of active mRNA corresponding to these proteins were determined in caerulein-stimulated animals and compared to those of controls infused with a 0.9% NaCl solution. For this purpose, the translation products synthesized in vitro in a rabbit reticulocyte lysate translation system were measured. Prolonged caerulein infusion had less pronounced effects on mRNA levels as determined by the relative synthesis of translation products than on individual secretory proteins. No changes in mRNA levels were observed during 6 h of hormonal stimulation, whereas a 7-fold increase in the ratio of trypsinogen to amylase synthesis was obtained previously. After 24 h of caerulein infusion, only a slight change in active mRNA coding for amylase (1.7-fold) and serine protease zymogens (1.4-fold) occurred as compared to 14-fold and 2-fold variations in the synthesis rates of the corresponding proteins. These findings indicate that caerulein exerts a predominantly translational control on the biosynthesis of pancreatic amylase, trypsinogen and chymotrypsinogen even after 24 h of hormonal stimulation. However, additional control at a transcriptional or post-transcriptional level (i.e. via messenger RNA stability) may well take place.

Amylases↗
PubMed1985

[Follow-up management of recently operated capsule and ligament injuries of the knee joint].

The guidelines for the treatment of ligament injuries of the knee joint are subject to continuous changes due to new experiences in the field of functional anatomy and pathophysiology, as well as to the progressive changes in surgical treatment. The authors suggest answers to the questions of immobilisation, appropriate support, mobilisation, etc., questions which as yet have no final and binding solutions. They also discuss the problems of muscle atrophy and the time at which sportive activities of varying strains may be taken up again.

Combined Modality Therapy↗
PubMed1984

[Cryotherapy. Behavior of joint temperature during ice application-- a basis for practical use].

Changes of intraarticular temperature were measured in ten young animals during long-term cryotherapy. The use of cold packs of -23 degrees C and an application time of 30 minutes resulted in a decrease of intraarticular temperature of means = 6.56 +/- 1.04 degrees C. The original temperature was reached again after an average of 215 minutes. With cryotherapy there is an initial reflex increase in temperature is the primary object of therapy, all movements commencement of application. Since movements of a joint result in the mixing of synovia of various temperatures, we recommend the following procedures in cryotherapy: 1. during the application of cold (cooling phase) the patient is ask to move his joint from time to time, in order to attain a faster and more effective decrease in temperature in the joint. 2. But in this cases, in which an intraarticular decrease in temperature is the primary object of therapy, all movements should be avoided during the phase of rewarming. The effect of long-term cryotherapy (Kern, 1980) is a decrease in temperature of sufficient magnitude and duration resulting in a reduction of joint metabolism, thereby of the activity of cartilage degrading enzymes. Accordingly, long-term cryotherapy can be recommended using cold packs of -20 to -23 degrees C for 30 minutes every 5 to 6 hours in acute rheumatic arthritis, posttraumatic oedema and in the acute therapy of sports injuries. A thin towel or blotting tissue is used to avoid local freezing. Slight exercise during the cooling phase can improve the results of cryotherapy.

Animals↗
PubMed1984

Effects of bile salts on permeability and morphology of main pancreatic duct in cats.

We studied the changes in permeability and morphology in the main pancreatic duct of cats after exposure of the duct to specific bile salts. Cats were anesthetized and the main pancreatic duct was cannulated in the tail and head of the pancreas. The duct was perfused with sodium cholate (1, 1.5, 2, 15 mM) or sodium glycodeoxycholate (1, 2, 15 mM) for 60 min at pressures which never exceeded 20 cm water. Then the duct was perfused with fluorescein-tagged dextran molecules of specific size (3000, 20,000, or 40,000 daltons). Recovery of the dextran from portal venous blood indicated that the duct was permeable to that particular dextran. Normally the ducts were impermeable to even the 3000-dalton dextran, and perfusion with either 1 mM cholate or glycodeoxycholate did not change this. However, perfusion with either bile salt at concentrations above 1 mM progressively increased duct permeability. At this highest bile salt concentrations used, the ducts became permeable to molecules as large as 20,000 daltons. Morphologic changes paralleled the changes in permeability. Control animals had pancreatic ducts whose ultrastructure was indistinguishable from normal. Perfusion of the ducts with low concentrations of bile salt for up to 60 min resulted only in a loss of microvilli from the cell surface and an increase in cytoplasmic phagolysosomes. Perfusion with higher concentrations of bile salt for 5-60 min induced progressively severe alterations. These included disruption of the tight junctions and the swelling of intercellular spaces between the duct cells, flattening of the duct epithelium, and eventual cell loss which left a break in the epithelial lining of the duct. These studies indicate that the pancreatic duct in cats, exposed to specific bile salts at physiological concentrations and pressures, undergoes marked structural alterations. The duct becomes permeable to molecules at least as large as 20,000 daltons, whereas it is normally impermeable to molecules as small as 3000 daltons.

Animals↗
PubMed1984

[Functional treatment method following patellar dislocations].

Acute, as well as recurrent, dislocations of the patella often are treated conservatively. However, an increasing number of authors are recommending early surgical treatment for primary, traumatic, as well as congenital, dislocations of the patella. The purpose of this report was to determine, which cases should be treated by operation or conservatively by a specific patellar protection program. This program includes four phases or rehabilitation: Phase I: Antiinflammatory measures (ice, compression and elevation, non steroidal medications), specific exercises (isometrics, straight leg raises with no weight, side leg raises with no weight), active range of motion, passive range of motion with no weights, flexibility of back, hip, hamstrings, quadriceps, ankle, groin and general exercises (swimming, general conditioning and opposite extremity program). Phase II: Continue isometric program, progressive-resistive program with ankle weights, continue flexibility program, lateral step-ups if terminal extension painful, eccentric isometrics if straight leg raises painful, continue swimming, may begin low resistance cycling if motion adequate. Phase III: Isotonic progressive-resistive exercise program, exercise to fatigue using weight or similar equipment (quadriceps, hamstrings, circuit exercises). Phase IV: Slow return to sports to develop specific neuromuscular skills at that sport, continued strength and endurance training. Continue weight machines and a full range of motion, running program, continued flexibility before and after athletic play.

Braces↗
PubMed1984

Hormonal stimulation in the exocrine pancreas results in coordinate and anticoordinate regulation of protein synthesis.

24-h intravenous caerulein infusion studies in the rat were combined with in vitro amino acid incorporation studies followed by high-resolution separation of proteins by two-dimensional isoelectric focusing and SDS gel electrophoresis to study the extent to which persistent changes in the biosynthesis of exocrine pancreatic proteins are regulated by cholecystokinin-like peptides. Beginning in the third hour of optimal hormone infusion at 0.25 microgram kg-1 h-1, changes were observed in the synthetic rates of 12 proteins, which progressed over the course of the 24-h study. Based on coordinate response patterns, exocrine proteins could be classified into four distinct groups. Group I (trypsinogen forms 1 and 2) showed progressive increases in synthetic rates reaching a combined 4.3-fold increase over control levels. Group II (amylase forms 1 and 2) showed progressive decreases in synthesis to levels 7.1- and 14.3-fold lower than control levels, respectively. Group III proteins (ribonuclease, chymotrypsinogen forms 1 and 2, procarboxypeptidase forms A and B, and proelastase 1) showed moderate increases in synthesis, 1.4-2.8-fold, and group IV proteins (trypsinogen 3, lipase, proelastase 2, and unidentified proteins 1-4) did not show changes in synthesis with hormone stimulation. Regulation of protein synthesis in response to caerulein infusion was specific for individual isoenzymic forms in the case of both trypsinogen and proelastase. The ratio of biosynthetic rates of trypsinogen forms 1 + 2 to amylase forms 1 + 2 increased from a control value of 0.56 to 24.4 after 24 h of hormonal stimulation (43.5-fold increase). Biosynthetic rates for an unidentified protein (P23) with an Mr = 23,000 and isoelectric point of 6.2 increased 14.2-fold, and the ratio of synthesis of P23 to amylase 2 increased 200-fold during caerulein infusion. During hormone stimulation the anticoordinate response in the synthesis of pancreatic glycosidases (decreased synthesis) and serine protease zymogens (increased synthesis) explain previous observations that showed little change in rates of total protein synthesis under similar conditions.

Amylases↗
PubMed1984

Treatment of duodenal ulcer with pirenzepine and cimetidine.

The purpose of this single blind controlled multicentre trial was to compare the relative effectiveness of pirenzepine and cimetidine in healing endoscopically proven duodenal ulcers. One hundred and twenty six patients with duodenal ulcer were treated with a daily dose of 100 mg pirenzepine (50 mg each before breakfast and before the evening meal), and 128 patients were treated with 1000 mg cimetidine (200 mg with breakfast, lunch, and evening meal and 400 mg at bedtime). Endoscopy was repeated after four weeks by an endoscopist who had not been informed about the treatment. Pirenzepine showed a healing rate of 64.3%, cimetidine one of 73.4%. This difference is not statistically significant (one-sided test: chi 1(2) = 2.48). After four weeks a higher proportion of first ulcers than of recurrent lesions was healed. Pain relief was rapidly achieved with both drugs. A significant trend in favour of cimetidine may, however, not be clinically relevant considering the small difference in the absolute numbers of pain free days and nights. Adverse effects were rare and reversible. We conclude that the efficacy of pirenzepine is similar to that of cimetidine in healing duodenal ulcers.

Anti-Ulcer Agents↗
PubMed1984

Two distinct adaptive responses in the synthesis of exocrine pancreatic enzymes to inverse changes in protein and carbohydrate in the diet.

Rates of synthesis of 16 individual pancreatic exocrine proteins; tissue concentrations of amylase, trypsinogen, and chymotrypsinogen; and morphological assessment of pancreatic acinar cells were studied in the exocrine pancreas in response to inverse changes in protein and carbohydrate in the diet, administered for 12 days. Two distinct patterns of response were observed. During adaptation to diets containing normal protein (22%) or increased levels of protein (30, 45, 64, and 82% protein) and correspondingly decreased levels of carbohydrate, amylase and the majority of protease zymogens were synthesized in direct proportion to the nutritional substrates carbohydrate and protein, respectively, in the diet. With increases in dietary protein, anticoordinate patterns of response in the synthesis of exocrine isoenzymes were observed: 0.4- to 2.0-fold increases in trypsinogen forms 1 and 2, chymotrypsinogen forms 1 and 2, proelastase 1, and procarboxypeptidases A and B; 5- to 7-fold decreases in amylase forms 1 and 2; and insignificant changes in trypsinogen 3, proelastase 2, lipase, and ribonuclease. During adaptation to diets containing normal protein (22%) or decreased levels of protein (0 or 10% protein) and correspondingly increased levels of carbohydrate, amylase and the majority of protease zymogens were synthesized in inverse proportion to nutritional substrates in the diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1983

[Treatment of whiplash injuries of the cervical spine with acupuncture].

30 patients with whiplash injuries were treated with aural-acupuncture. The points were chosen according to a special programme. Acupuncture proved an effective form of therapy for treatment of accident patients with whiplash injuries, representing a valuable supplement to the field of rehabilitation.

Acupuncture Therapy↗
PubMed1983

[The effect of standardized acupuncture programs in the after-care of accident patients].

153 patients suffering from pain, edematous conditions, and impaired movement following traumas sustained in accidents were treated or after-treated with acupuncture. Acupuncture was applied in adherence to a standardized program according to the individual types of injury. The stimulus was applied by means of steel needles inserted into body as well as ear acupuncture points. In all 9 groups, improvement of the painful condition was significant to highly significant as it was regarding improvement of the movement impairment, the latter not having been emphasized in the other 3 groups. Remaining complaints of long standing following accident traumas could also be positively influenced. Acupuncture proved itself to be an effective form of therapy for after-treatment of accident patients, presenting a valuable supplement to the field of rehabilitation, especially when combined with other physical therapeutic measures.

Acupuncture Therapy↗
PubMed1983

[Testing the effect of acupuncture in accident patients using skin temperature measurements].

Skin temperature was studied on a group of 54 patients suffering from accident traumas and 20 healthy probands during and after treatment. In all patients there was a very significant rise in skin temperature in the area of the lesion which persisted beyond the treatment period, and in some cases even increased. This effect was also observed to a lesser extent on the contralateral, untreated extremity. No change in skin temperature was observed in the healthy probands who were treated in the same manner. This leads to the conclusion that needle stimuli in the area of lesions have not only a local, hyperemic effect, but also demonstrate superregional actions; this is, however, dependent on the integrity of the organism.

Acupuncture Therapy↗