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Biomedical subjects

K Heller

Publications and source records attributed to K Heller.

At least 109 records · Page 6Linked to original sources
PubMed1986

Metastatic trichomatricial carcinoma.

Trichomatricial carcinoma has been recently recognized as a rare malignant variant of pilomatricoma with a potential for local recurrence and, rarely, for distant metastases. We describe such a tumor in a 52-year-old man who developed local recurrence and axillary lymph node metastases within six months of local excision, followed by bilateral pulmonary metastases and 2 1/2 years later by death due to disseminated tumor. This, to our knowledge, is the second reported case of metastasizing trichomatricial carcinoma.

Carcinoma↗
PubMed1985

Response biases and the relation between negative life events and psychological symptoms.

This research was an investigation of whether reporting biases can account for the correlation between negative life events (as measured via life events questionnaires) and subclinical psychological symptoms. Subjects completed two life events scales, a measure of psychological symptoms, a measure of depression, and a measure of social desirability. Friends were asked to report about life events experienced by the subjects. No evidence was found for a subject reporting bias associated with social desirability, depression, or symptoms. In fact, for one of the life events scales, depression was significantly associated with a higher rate of agreement between subjects and friends as to which negative events occurred to subjects. Moreover, there were significant correlations between symptom and depression measures and life events measures that were free of subject-reporting biases (subjects' negative life events reported by both subjects and their significant others, as well as subjects' negative life events as reported by significant others alone). These data suggest that response biases may not be able to account for the relation between negative events and psychological symptoms. Thus the hypothesis that negative life events play a significant role in symptom development remains plausible.

Adjustment Disorders↗
PubMed1985

Cloning and expression of the gene for the vitamin B12 receptor protein in the outer membrane of Escherichia coli.

The transport of cyanocobalamin (vitamin B12) in cells of Escherichia coli is dependent on a receptor protein (BtuB protein) located in the outer membrane. A 9.1-kilobase pair BamHI fragment carrying the btuB gene was cloned from a specialized transducing phage into multicopy plasmids. Insertions of transposon Tn1000 which prevented production of the receptor localized btuB to a 2-kilobase pair region. Further subcloning allowed isolation of this region as a 2.3-kilobase pair Sau3A fragment. The BtuB+ plasmids were shown by maxicell analysis to encode a polypeptide with a molecular weight of 66,000 in the outer membrane. This polypeptide was missing in cells with Tn1000 insertions in btuB and was reduced in amount upon growth of plasmid-bearing cells in repressing concentrations of vitamin B12. Several Tn1000 insertions outside the 5' end of the coding region exhibited reduced production of receptor. A deletion at the 3' end of btuB resulted in formation of an altered receptor. Amplified production of this polypeptide was associated with increased levels of binding of the receptor's ligands (vitamin B12 and phage BF23), increased rates of vitamin B12 uptake, and altered susceptibility to the group E colicins. Deficiency in various major outer membrane proteins did not affect production of the btuB product, and the amplified levels of this protein partially reversed the tolerance to E colicins seen in these mutants.

Bacterial Outer Membrane Proteins↗
PubMed1985

Nucleotide sequence of the gene for the vitamin B12 receptor protein in the outer membrane of Escherichia coli.

The nucleotide sequence of a 2220-base-pair fragment containing the btuB gene of Escherichia coli was determined. There was a single open reading frame which was translated into a 614-amino-acid polypeptide, the first 20 amino acids of which comprised a typical leader sequence. The putative mature or processed form had a molecular weight (66,400) and a composition in close agreement with that determined for the purified receptor. The distribution of amino acids in the receptor protein was similar to that of other outer membrane proteins, showing a fairly even distribution of charged residues and the absence of extensive hydrophobic stretches. The btuB451 mutation appears to alter the receptor to eliminate its ability to function in vitamin B12 uptake without affecting its ligand binding properties. The sequence of the DNA from this mutant was determined and revealed a leucine-to-proline (C-to-T transition) change in the eighth amino acid of the mature form.

Amino Acid Sequence↗
PubMed1985

[2-frequency artificial respiration--a new therapeutic concept].

A new respiration system is described. The system has been developed for the therapy of very ill newborn and premature infants (RDS stage IV, gestation age less than 28 weeks, severe pneumonia etc.). The special feature of the new respiratory device is an alternating between cycles with low frequencies and relatively high amplitudes, and breathes with low amplitudes and relatively high frequencies.

Humans↗
PubMed1985

[Infant hypotonia, obesity, hypogenitalism and oligophrenia--new viewpoints on the etiology and symptoms of Prader-Willi syndrome].

We present four cases of Prader-Willi syndrome. Two of them have an abnormality of a chromosome 15, the other both show different chromosomal abnormalities. Translocations or deletions were found recently in the bands 15q11/12 in about 60% of the cases of Prader-Willi syndrome. The consequences for diagnosis, symptomatology and genetic counselling of the syndrome are discussed.

Child↗
PubMed1983

Measures of perceived social support from friends and from family: three validation studies.

Three studies are described in which measures of perceived social support from friends (PSS-Fr) and from family (PSS-Fa) were developed and validated. The PSS measures were internally consistent and appeared to measure valid constructs that were separate from each other and from network measures. PSS-Fr and PSS-Fa were both inversely related to symptoms of distress and psychopathology but the relationship was stronger for PSS-Fa. PSS-Fr was more closely related to social competence. PSS-Fa was unaffected by either positive or negative mood states (self-statements), but the reporting of PSS-Fr was lowered by negative mood states. High PSS-Fr subjects were significantly lower in trait anxiety and talked about themselves more to friends and sibs than low PSS-Fr subjects. Low PSS-Fa subjects showed marked verbal inhibition with sibs.

Affective Symptoms↗
PubMed1983

[Complete duplication of the small intestine in childhood].

The article reports on two cases of complete duplication of the small intestine in an infant of 7 months of age (female) and a boy aged 3 1/2 years. The almost complete lining of the duplicated small intestine with gastric mucosa resulted in massive haemorrhages. These haemorrhages, in conjunction with ileus, were the indications for an operation. Mucosectomy was performed in the region of the duplication. Such removal of the mucosa is recommended in complete duplication of the small intestine and in partial tubular forms.

Anemia↗
PubMed1983

Concomitant changes of membrane leak permeability and phospholipid dynamics in erythrocytes subjected to chemical and physical membrane perturbation.

A mild selective oxidant of erythrocyte membrane SH-groups producing SS-bonds and inducing reversible crosslinking of spectrin, as well as strong less specific oxidants which produce a more extensive modification of membrane proteins and peroxidation of lipids and dielectric breakdown of the membrane induce formation of structural defects acting as aqueous pores and reorientation sites for phospholipids. The coupling of a process requiring hydrophilic structures (leak permeability) and a process also involving hydrophobic constituents (flip of phospholipids) suggests that the membrane lipid domain is involved in the effects.

Carbon Radioisotopes↗
PubMed1982

Polymannose O-antigens of Escherichia coli, the binding sites for the reversible adsorption of bacteriophage T5+ via the L-shaped tail fibers.

A study of the adsorption kinetics of T5+ and the tail fiber-less mutant hd-2 to lipopolysaccharides of various Escherichia coli strains demonstrated T5+ binding to the O-antigen of th O8 and O9 types. Incorporation of radioactive mannose into the phosphomannose isomerase-deficient strain E. coli F860 O9 pmi allowed the derivation of the number of O-antigens per cell required to increase T5 adsorption. With more than 500 O-antigen molecules, acceleration of T5+ adsorption was observed. The highest adsorption rate was obtained when nearly all lipopolysaccharide molecules were substituted with a polymannose O-antigen. Inhibition studies with purified components of an enzymatically degraded lipopolysaccharide of the O8 type showed that among the mannosides tested the smallest unit, the trimannoside, was the strongest inhibitor of T5+ binding. We conclude that the reversible preadsorption to the O8 and O9 polymannose antigens increases the rate of infection via the cellular receptor protein encoded by the fhuA (formerly tonA) gene.

Antigens, Bacterial↗