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Biomedical subjects

L Kauffman

Publications and source records attributed to L Kauffman.

6 recordsLinked to original sources

Bios data analyzer.

The Bios Data Analyzer (BDA) is a set of computer programs (CD-ROM, in Sabelli et al., Bios. A Study of Creation, 2005) for new time series analyses that detects and measures creative phenomena, namely diversification, novelty, complexes, nonrandom complexity. We define a process as creative when its time series displays these properties. They are found in heartbeat interval series, the exemplar of bios .just as turbulence is the exemplar of chaos, in many other empirical series (galactic distributions, meteorological, economic and physiological series), in biotic series generated mathematically by the bipolar feedback, and in stochastic noise, but not in chaotic attractors. Differencing, consecutive recurrence and partial autocorrelation indicate nonrandom causation, thereby distinguishing chaos and bios from random and random walk. Embedding plots distinguish causal creative processes (e.g. bios) that include both simple and complex components of variation from stochastic processes (e.g. Brownian noise) that include only complex components, and from chaotic processes that decay from order to randomness as the number of dimensions is increased. Varying bin and dimensionality show that entropy measures symmetry and variety, and that complexity is associated with asymmetry. Trigonometric transformations measure coexisting opposites in time series and demonstrate bipolar, partial, and uncorrelated opposites in empirical processes and bios, supporting the hypothesis that bios is generated by bipolar feedback, a concept which is at variance with standard concepts of polar and complementary opposites.

Creativity↗

Sentinel node biopsy for the detection of head and neck melanoma: a review.

Worldwide incidence of malignant melanoma is on the rise. Early detection of this malignancy is key to survival, and in the case of more advanced malignancy, early and effective detection of micrometastatic disease is crucial for staging and therapy. Because melanoma spreads primarily via lymphatic drainage patterns, effective methods for tracing these pathways are of paramount importance. The authors summarize the efficacy of blue dye, gamma probe, and lymphoscintigraphy detection methods, both individually and combined; the "missed disease" (or false-negative) rate; and the clinical discordance between expected and actual location of metastatic disease in head and neck melanoma. A clinical meta-analysis of current studies in head and neck melanoma was used to evaluate clinical data. A success rate of 95% to 100% for detection of sentinel lymph nodes can be achieved when blue dye, gamma probe, and lymphoscintigraphy techniques are combined. This is associated with a false-negative rate of 7.7% to 10.4%. With respect to intermediate-depth melanomas of the head and neck, a significant discordance exists between expected and actual lymphatic drainage patterns. This problem is best addressed using a combination of lymphoscintigraphy, blue dye, and gamma probe localization, which yields a success rate of 95% to 100% for detection of sentinel lymph nodes and a low false-negative rate of 7.7% to 10.4%. In the instance of a failed study, one in which sentinel nodes are not detected by the aforementioned methods, elective node dissection is the treatment modality of choice.

False Negative Reactions↗

A simple mechanism for the avoidance of entanglement during chromosome replication.

The interphase nucleus of the human eukaryotic cell, before DNA replication, contains 46 linear DNA molecules, each of the order of centimeters in length, in a spherical nucleus with a diameter of 3-10 microns. How does the cell avoid topological entanglements between the 92 linear DNA molecules following replication? A model of chromosome replication is introduced, based on the assumption of the existence of a physical linkage between diverging growing forks during eukaryotic chromosome replication. This basic model is shown to be sufficient for the avoidance of DNA duplex entanglements during DNA replication. The model also suggests structural characteristics of chromosomes at various points in the cell cycle and provides a possible partial mechanism for chromosome condensation at the end of replication.

Animals↗

Sweat gland carcinoma in a human immunodeficiency virus-infected patient.

Eccrine (sweat gland) carcinoma is a rare form of skin cancer that may be locally destructive. It is known to recur after resection and can metastasize to regional or distant lymph nodes. There have been two reported cases in association with patients immunocompromised as the result of organ transplantation (I. Penn: Prog Allergy. 37: 259, 1986). We report here the first case of sweat gland carcinoma in a patient infected with the human immunodeficiency virus.

Acquired Immunodeficiency Syndrome↗

Bone-marrow transplantation for congenital erythropoietic porphyria.

Congenital erythropoietic porphyria, a disorder of haem synthesis, is caused by uroporphyrinogen III synthase deficiency in bone-marrow normoblasts. Uroporphyrins and coproporphyrins accumulate and cause oxidative damage to cells exposed to sunlight. Uroporphyrin overproduction was greatly reduced and skin changes reversed in a girl who received a bone-marrow graft from an HLA-identical sibling at 10 years of age. The patient died 11 months after transplantation because of severe progressive pneumonitis and encephalopathy associated with cytomegalovirus infection, but the encouraging response up to 8 months after engraftment indicates a possible benefit of bone-marrow transplantation in the treatment of this rare but usually fatal inherited disease.

Bone Marrow Transplantation↗