Biomedical subjects

H Berberich

Publications and source records attributed to H Berberich.

4 recordsLinked to original sources

PubMed2001

Homoleptic lanthanide amides as homogeneous catalysts for alkyne hydroamination and the Tishchenko reaction.

The homoleptic bis(trimethylsilyl)amides of Group 3 metals and lanthanides of the general type [Ln[N(SiMe3)2]3] (1) (Ln=Y, lanthanide) represent a new class of Tishchenko precatalysts and, to a limited extent, precatalysts for the hydroamination/cyclization of aminoalkynes. It is shown that 1 is the most active catalyst for the Tishchenko reaction. This contribution presents investigations on the scope of the reaction, substrate selectivity, lanthanide-ion size-effect, and kinetic/mechanistic aspects of the Tishchenko reaction catalyzed by 1. The turnover frequency is increased by the use of large-center metals and electron-withdrawing substrates. The reaction rate is second order with respect to the substrate. While donor atoms, such as nitrogen, oxygen, or sulfur, on the substrate decrease the turnover frequency, 1 shows a tolerance for a large number of functional groups. For the hydroamination/cyclization of aminoalkynes, 1 is less active than the well-known metallocene catalysts. On the other hand, 1 is much more readily accessible (one-step synthesis or commercially available), than the metallocenes and might therefore be an attractive alternative catalyst.

Journal Article↗

PubMed1988

Immunization with rough mutants of Salmonella minnesota: protective activity of IgM and IgG antibody to the R595 (Re chemotype) mutant.

We evaluated the immunoglobulin class responsible for the protective activity in serum obtained from humans and rabbits after immunization with the R595 (Re chemotype) mutant of Salmonella minnesota. Whole serum obtained before immunization and the IgG and IgM fractions failed to protect mice against lethal challenge with viable Klebsiella pneumoniae or Morganella morganii or with Salmonella typhi lipopolysaccharide (LPS). The protective activity of postimmunization serum resided solely in IgM antibody, whereas IgG antibody exhibited no protective activity. IgM antibody to the Re mutant was protective against bacterial challenge with both test strains of bacteria and S. typhi LPS. IgM antibody, at approximately the same concentration present in postimmunization serum, increased the LD50 of K. pneumoniae from less than 8.0 x 10(2) to greater than 2.0 x 10(4). These findings indicate that commercially prepared human IgG with high titers of antibody to antigens of the core portion of LPS would have little clinical utility.

Animals↗

PubMed1988

Immunization with rough mutants of Salmonella minnesota: initial studies in human subjects.

Vaccines prepared from unheated and boiled, acetone-precipitated Salmonella minnesota R595 (Re chemotype mutant) were administered subcutaneously to 122 healthy volunteers. Titers of antibody to Re lipopolysaccharide, the basal core structure of endotoxin, as measured by indirect hemagglutination, rose in a dose-responsive fashion after immunization. Febrile reactions, usually mild, occurred after 7% of injections with the highest doses (2.0 and 3.0 x 10(10) organisms), and mild local soreness and tenderness were noted after approximately one-third of injections. Passive immunization of mice with sera from immunized subjects demonstrated that protective activity against challenge with both heterologous, viable gram-negative bacilli and endotoxin developed. Although measuring serum protective activity, developing a serological assay that correlates with protective activity, and potential vaccine toxicity remain problems, immunization of humans with the Re mutant results in serum protective activity against endotoxin and viable bacilli and has the potential for clinical usefulness.

Adolescent↗

PubMed1984

Long-term development of a primary lung sarcoma, probably lymphangiosarcoma--a case report.

A small primary lung lesion had remained unchanged in size over a period of 8 years. Within the ensuing 2 years rapid tumor growth occurred. On operation the surgical specimen revealed a tumor mass of 87.2 cm3. Within 6 months after resection, the tumor occurred on the same side. Extensive tumor infiltration of the chest wall prevented any further surgery. The histo-morphologic picture of both lesions was consistent with a lymphangiosarcoma without evidence of high grade malignancy. The patient died of cardio-respiratory insufficiency due to extension of the tumor mass. Unfortunately no autopsy was performed. Tumor growth rates, macroscopic reconstruction and electron microscopic evaluations are presented. This case report again points out that size and long-time stability of solitary lung nodules are not necessarily reliable criteria for assessing prognosis.

Adult↗