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Biomedical subjects

K Keller

Publications and source records attributed to K Keller.

At least 109 records · Page 6Linked to original sources
PubMed1984

Enzyme-linked lectinosorbent assay (ELLA) for detecting Bacillus anthracis.

An enzyme-linked lectinosorbent assay (ELLA) has been developed for the rapid identification of Bacillus anthracis. Using two different lectin-conjugates, the ELLA test can differentiate Bacillus anthracis from closely related species, such as Bacillus cereus and Bacillus cereus var. mycoides, in approximately two hours. In addition to having high specificity, the test can also detect small numbers of the bacterium.

Bacillus↗
PubMed1984

Lectins in diagnostic microbiology.

Current literature suggests that lectins are becoming valuable reagents for the laboratory identification of infectious agents. The identification of bacteria, fungi, or protozoa may be confirmed if they bind to or agglutinate with certain lectins. Assay kits utilizing specific lectin agglutination reactions, coupled with conventional enzyme determinations, have been proposed for several bacteria. Factors such as specificity, stability, assay rapidity, and costs combine to make lectins attractive diagnostic reagents. It is likely that the use of lectins in diagnostic microbiology will continue to grow.

Bacillus↗
PubMed1983

[Ultrasonic diagnosis in children with mesenteric cysts].

Two cases of Mesenteric Cysts in infancy are described. Since there is no continuity with the lumen of the bowel radiological evaluation may be very difficult. In contrast abdominal sonography can give information about size, contents and position in relation to other abdominal organs. The use of ultrasound shortens the preoperative workup and certainly reduces the number of X-ray examinations.

Female↗
PubMed1982

Effects of cell motility and chemotaxis on microbial population growth.

A mathematical model is developed to elucidate the effects of biophysical transport processes (nutrient diffusion, cell motility, and chemotaxis) along with biochemical reaction processes (cell growth and death, nutrient uptake) upon steady-state bacterial population growth in a finite one-dimensional region. The particular situation considered is that of growth limitation by a nutrient diffusing from an adjacent phase not accessible to the bacteria. It is demonstrated that the cell motility and chemotaxis properties can have great influence on steady-state population size. In fact, motility effects can be as significant as growth kinetic effects, in a manner analogous to diffusion- and reaction-limited regimes in chemically reacting systems. In particular, the following conclusions can be drawn from our analysis for bacterial populations growing at steady-state in a confined, unmixed region: (a) Random motility may lead to decreased population density; (b) chemotaxis can allow increased population density if the chemotactic response is large enough; (c) a species with superior motility properties can outgrow a species with superior growth kinetic properties; (d) motility effects become greater as the size of the confined growth region increases; and (e) motility effects are diminished by significant mass-transfer limitation of the nutrient from the adjacent source phase. The relationships of these results for populations to previous conclusions for individual cells is discussed, and implications for microbial competition are suggested.

Bacterial Physiological Phenomena↗
PubMed1982

Rapid cellular regulation of D-glucose transport in cultured neural cells.

Previous studies have revealed two different kinds of regulation of glucose utilization in cell lines derived from the nervous system (Keller et al., 1981). We found glucose metabolism of C-6 glioma cells to be limited and regulated by membrane transport. In contrast, glucose utilization of C-1300 neuroblastoma (N2A) cells was limited by the known regulatory enzymes of the Embden-Meyerhof pathway. Under the given experimental conditions the "membrane-limited" C-6 glioma cells were characterized by periodically changing glucose transport rates and very low intracellular glucose concentrations, which remained constant in spite of widely differing transport rates. These findings suggest the close functional coupling between transport and phosphorylation required for the regulation of glucose transport by cellular metabolic needs.

Animals↗
PubMed1981

D-Glucose transport in cultured cells of neural origin: the membrane as possible control point of glucose utilization.

The function of plasma membrane as control point of glucose metabolism has been studied in confluent monolayer of C1300 neuroblastoma (N2A) and glioma (C6) cells. In neuroblastoma, steady state intracellular glucose concentration reached the extracellular levels, while intracellular contents in C6 glioma cells remained very low. In C6 glial cells the amount of glycogen as source of energy was much higher than that found in C1300 neuroblastoma cells. Influx rates of D-glucose in C6 glioma cells were only half those found in neuroblastoma cells. During the influx period (0-40 s) the transport of glucose in these cells did not exceed the phosphorylation rate, whereas a steady, time-dependent increase in glucose content was observed in neuroblastoma cells. While glucose uptake in neuroblastoma cells seems to be regulated at the level of phosphorylating enzymes, the control point in C6 glioma is believed to be membrane transport.

Animals↗
PubMed1980

Further studies on the nature of red fluorescent structures in neuroblastoma monolayer cells vitally stained with acridine orange.

The nature of red fluorescent particles in vitally acridine orange stained C 1300 neuroblastoma monolayer cells was evaluated by electron microscopy, cytofluorometry, cytopharmacological and cell fractionation studies. At the ultrastructural level the distribution of red fluorescent granules correlated with that of the Golgi complex and Golgi derived structures during various stages of differentiation, mitosis, and under colcemid treatment. Cytopharmacological studies revealed that red fluorescence was displaced in a concentration and time dependent manner with the basic drugs chloroquine and quinacrine. Subcellular fractionation studies showed that acridine orange was concentrated in fractions that also contained the highest amount of acid phosphatase and electron dense vesicles. Vital acridine orange staining of neuroblastoma cells in culture can give information on the relationship between Golgi-derived vesicles and cell functions like proliferation and differentiation. The influence of drugs on these processes can be studied.

Acid Phosphatase↗
PubMed1980

[Factors influencing dental caries in school children in a city with fluoridated water].

In a joint study by the school health and the school dental health service 4386 children were examined and their nutritional habits recorded. Analysis shows that mainly the consumption of sweets between regular meals and insufficient dental hygiene are responsible for the presence of caries. While health education for dental hygiene is presently given at school nutrition education is still a neglected subject.

Adolescent↗
PubMed1980

Clinical breast examination and breast self-examination experience in a family practice population.

A patient questionnaire, chart audit, and resident questionnaire were used to assess clinical breast examination and breast self-examination experience in a family practice patient population. It was found that approximately 50 percent of the women studied reported annual routine breast examinations during a five-year study period. However, the residency program was responsible for providing or documenting annual clinical examinations in only ten percent of the population. Although 99 percent of the women knew about Breast Self-Examination (BSE), only 19 percent practiced monthly BSE. A positive association was found between the physician's active teaching of BSE and the patient's confidence in and regular practice of BSE. The low number of annual clinical examinations and low performance of BSE may be explained partially by the physician's setting too narrowly the parameters of when a clinical breast examination and BSE teaching could be done appropriately, ie, a pap smear/pelvic or general examination. A more aggressive approach by the physician may increase the number of women who get routine clinical breast examinations and who supplement them by monthly BSE.

Adult↗