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M Hoff

Publications and source records attributed to M Hoff.

At least 91 records · Page 5Linked to original sources
PubMed1987

Variable number of tandem repeat (VNTR) markers for human gene mapping.

A large collection of good genetic markers is needed to map the genes that cause human genetic diseases. Although nearly 400 polymorphic DNA markers for human chromosomes have been described, the majority have only two alleles and are thus uninformative for analysis of genetic linkage in many families. A few known marker systems, however, detect loci that respond to restriction enzyme cleavage by producing a fragment that can have many different lengths. This polymorphism is due to variation in the number of tandem repeats of a short DNA sequence. Because most individuals will be heterozygous at such loci, these markers will provide linkage information in almost all families. Ten oligomeric sequences derived from the tandem repeat regions of the myoglobin gene, the zeta-globin pseudogene, the insulin gene, and the X-gene region of hepatitis B virus, were used to develop a series of single-copy probes. These probes revealed new, highly polymorphic genetic loci whose allele sizes reflected variation in the number of tandem repeats.

Chromosome Mapping↗
PubMed1987

A primary genetic linkage map for human chromosome 12.

A primary genetic map for human chromosome 12 has been constructed from data on 23 restriction fragment length polymorphic systems collected in 38 normal families with large sibships. Linkage analysis of the genotypic data has ordered 16 loci into a continuous genetic map of 111 cM in males and 258 cM in females. Although most of the genetic map reflects a higher rate of recombination in females relative to males, significantly more frequent recombination was observed in males than in females in intervals between loci on the distal portion of the short arm of the chromosome. The mapping data shown here will serve as a first step toward a high-resolution genetic map for human chromosome 12.

Animals↗
PubMed1986

Further linkage data on cystic fibrosis: the Utah Study.

We reported earlier complete linkage between cystic fibrosis and an RFLP of the met proto-oncogene revealed by the probe pmetH. Another clone, pmetD, detects another polymorphism with the TaqI restriction enzyme. Further linkage studies, now involving 22 families, have confirmed the tight linkage of cystic fibrosis to the MET and D7S8 loci. Significant allelic association was found between CF and allelic series defined by the pmetH probe.

Alleles↗
PubMed1985

Expression of epidermal keratins and filaggrin during human fetal skin development.

The major structural proteins of epithelia, the keratins, and the keratin filament-associated protein, filaggrin, were analyzed in more than 50 samples of human embryonic and fetal skin by one-dimensional SDS PAGE and immunoblotting with monoclonal and polyclonal antibodies. Companion samples were examined by immunohistochemistry and electron microscopy. Based on structural characteristics of the epidermis, four periods of human epidermal development were identified. The first is the embryonic period (before 9 wk estimated gestational age), and the others are within the fetal period: stratification (9-14 wk), follicular keratinization (14-24 wk), and interfollicular keratinization (beginning at approximately 24 wk). Keratin proteins of both the acidic (AE1-reactive, type I) and the basic (AE3-reactive, type II) subfamilies were present throughout development. Keratin intermediate filaments were recognized in the tissue by electron microscopy and immunohistochemical staining. Keratins of 50 and 58 kD were present in the epidermis at all ages studied (8 wk to birth), and those of 56.5 and 67 kD were expressed at the time of stratification and increased in abundance as development proceeded. 40- and 52-kD keratins were present early in development but disappeared with keratinization. Immunohistochemical staining suggested the presence of keratins of 50 and 58 kD in basal cells, 56.5 and 67 kD in intermediate cells, and 40 and 52 kD in the periderm as well as in the basal cells between the time of stratification and birth. Filaggrin was first detected biochemically at approximately 15 wk and was localized immunohistochemically in the keratinizing cells that surround hair follicles. It was identified 8-10 wk later in the granular and cornified cell layers of keratinized interfollicular epidermis. These results demonstrate the following. An intimate relationship exists between expression of structural proteins and morphologic changes during development of the epidermis. The order of expression of individual keratins is consistent with the known expression of keratins in simple vs. stratified vs. keratinized epithelia. Expression of keratins typical of stratified epithelia (50 and 58 kD) precedes stratification, and expression of keratins typical of keratinization (56.5 and 67 kD) precedes keratinization, which suggests that their expression marks the tissue commitment to those processes. Because only keratins that have been demonstrated in various adult tissues are expressed during fetal development, we conclude that there are no "fetal" keratins per se.(ABSTRACT TRUNCATED AT 400 WORDS)

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

[High blood triiodothyronine and the euthyroid state].

A high excess of circulating T3 was observed in an euthyroid woman. Agarose gel electrophoresis of serum preincubated with 125I-T3 revealed an abnormal T3-binding in gamma-globulin zone. This binding interfered with the hormone radioimmunoassay. Immunological characterization identified this protein as an IgG-K and IgG-lambda polyclonal antibody that bound T3 but not T4. Scatchard analysis of 125I-T3 binding to the gamma-globulin fraction isolated showed a single class of binding sites with a high affinity Ka = 0.4 X 10(9) L/M and maximal binding capacity of 5.2 X 10(-9) M.

Aged↗
PubMed1984

A second type II restriction endonuclease from Thermus aquaticus with an unusual sequence specificity.

A type II restriction endonuclease activity free of TaqI was prepared from Thermus Aquaticus YT. The fraction contains two endonucleolytic components with apparently different specificities, however the major activity is sufficiently dominant to allow partial digestion analysis of the position of recognition sites. A precise determination of the location of cleavage sites in pBR322 DNA and a computer-aided search for regions of homology in the vicinity of the cut sites indicate that this enzyme recognizes the nonpalindromic sequences GACCGA or CACCCA. Other related sequences are not cleaved, in particular, GACCCA and CACCGA, indicating that the enzyme requires the identity of nucleotides in the first and fifth positions, a type of specificity that has not been previously reported. The position of cleavage is located outside of the site and is represented as: (Formula: see text).

Base Sequence↗
PubMed1984

[Enamel defects in tuberous sclerosis: hard facts of diagnostic importance].

Tuberous sclerosis is a complex syndrome. Recognition of the disease can be very difficult because of its incomplete forms. In this article a new symptom of possibly great diagnostic value is discussed, namely the presence of enamel defects in patients with tuberous sclerosis. For a clear understanding and correct interpretation of enamel defects in general, the role of the odontogenesis, the amelogenesis and the different types of developmental disturbances is explained. A review is given of all published investigations concerning the presence of enamel defects in tuberous sclerosis. The conclusion is that the enamel defects may be of great importance for an early diagnosis as well as for a possible revise of the penetrance and mutation rate of the disease.

Amelogenesis↗