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Biomedical subjects

K Lange

Publications and source records attributed to K Lange.

At least 181 records · Page 10Linked to original sources
PubMed1983

Some combinatorial problems of DNA restriction fragment length polymorphisms.

Recombinant DNA techniques provide a means of defining new polymorphisms at the DNA sequence level. Polymorphisms arise when individuals differ in the location and number of sites where restriction endonucleases can cleave their DNA. Each such site exhibits two possible states: one for the presence of a specific endonuclease recognition sequence, the other for its absence. The states of a system of adjacent sites can be revealed experimentally by cleaving a person's DNA into a set of fragments. For experimentally well-understood systems of sites, we consider problems of counting numbers of possible fragments, haplotypes, genotypes, and phenotypes, and the means of resolving phenotype-genotype ambiguities. The degree of polymorphism generated by such systems and the importance to gene mapping are discussed.

Base Sequence↗
PubMed1983

On Ewens' equivalence theorem for ascertainment sampling schemes.

The usual likelihood formulations for segregation analysis of a genetic trait ignore both the at-risk but unobservable families and the demographic structure of the surrounding population. Families are not ascertained if, by chance, they have no affected members or if the affected members are not ascertained. Ewens has shown that likelihoods which take into explicit account both unobservable families and demographic parameters lead to the same maximum likelihood estimates of segregation and ascertainment parameters as the usual likelihoods. This paper provides an alternative proof of Ewens' theorem based on the Poisson distribution and simple continuous optimization techniques.

Genetics, Population↗
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↗
PubMed1982

Calculation of the equilibrium distribution for a deleterious gene by the finite Fourier transform.

In a population of constant size every deleterious gene eventually attains a stochastic equilibrium between mutation and selection. The individual probabilities of this equilibrium distribution can be computed by an application of the finite Fourier transform to an appropriate branching process formula. Specific numerical examples are discussed for the autosomal dominants, Huntington's chorea and chondrodystrophy, and for the X-linked recessive, Becker's muscular dystrophy.

Female↗
PubMed1982

How many polymorphic genes will it take to span the human genome?

It is desirable to know how many polymorphic marker loci will be required so that every human genetic locus can be mapped by classical pedigree methods to a specific region of a specific chromosome. Assuming a total autosomal map length of 33 morgans, it would take only about 33/(2d) evenly spaced markers for every locus to be within d morgans of a marker. Taking into account that the markers will fall randomly along the genome, we show that a much larger number of such loci will have to be isolated and tested before the goal of a saturated gene map is reached.

Chromosome Mapping↗
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↗
PubMed1981

Osteitis in early syphilis. A case report.

Osteitis of the tibia was diagnosed in a patient presenting with secondary syphilis. The course of the illness indicates that pain in bones in secondary syphilis may be the first symptom of an otherwise inapparent osteitis.

Adult↗
PubMed1981

Pyriderm shampoo in the treatment of Pediculosis capitis.

112 patients with head lice were treated with a shampoo containing pyrethrins. All were treated twice with an interval of one week. At examination immediately before the second treatment, 6 patients had small, newly hatched lice, and one patient had both small and mature lice--probably due to reinfestation. This patient was lice-free after the third treatment, the other patients after the second treatment. It is concluded that pyrethrins are highly effective against head lice and have the advantages of a low toxicity to mammals and a short contact time.

Humans↗
PubMed1981

Depression of endostreptosin, streptolysin O and streptozyme antibodies in patients with idiopathic nephrosis with and without a nephrotic syndrome.

We determined antibody titers to Endostreptosin (ESS), a recently described protein antigen in the cytoplasm and the plasma membrane of Group A streptococci in 286 normals of different age groups and in 34 children and 19 adults who had or had had at one time a nephrotic syndrome due to idiopathic nephrosis. Antistreptolysin O titers were also determined in 33 of the idiopathic nephrotics. Similarly, antibody titers to Streptozyme were determined in 21 patients with idiopathic nephrosis and 61 normals with a similar age distribution. Severe depression of these antibody titers was found in almost all patients with this disease not only during the presence of a nephrotic syndrome but for long periods up to 20 years following an episode of a nephrotic syndrome when the patients were in complete remission. Patients with a nephrotic syndrome due to chronic glomerulonephritis (5), S.L.E. (4), membranous nephropathy (5), diabetes mellitus (1) or amyloidosis (1) did not show abnormally low values for antibodies to Endostreptosin, Streptolysin O or Streptozyme. High-dose steroid medication as such for prolonged periods of time does not depress Endostreptosin or Streptolysin O antibody titers below the expected mean, as demonstrated in 15 patients with S.L.E.

Adolescent↗
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↗