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Biomedical subjects

A Hallberg

Publications and source records attributed to A Hallberg.

95 records · Page 6Linked to original sources
PubMed1976

Alport's syndrome. A report of three Swedish families.

Three families with hereditary nephritis of Alport's type have been studied with particular emphasis on the occurrence of symptoms and signs in different sexes and age groups. Part of the material was tested for impaired hearing or eye anomalies which may be the sole manifestation of Alport's yndrome. The youngest patients were 3-4 years of age, and the proportion of diseases individuals increased with age. In two of the families about half of the investigated males or females were affected whereas in the third family all but one of 16 investigated individuals were affected. In this last family the kidney disease was exceptionally severe, but no differences in the histopathology of the kidney lesions were seen between the families. In all the families renal symptoms progressed more rapidly in males than in females. Affected as well as unaffected sons and daughters were born to healthy as well as to diseased mothers. In contrast, healthy fathers produced only unaffected children. Diseased fathers produced only daughters, two-thirds of whom were affected. It is concluded that Alport's syndrome in these three families most probably is transmitted by autosomal dominant inheritance with variations in expression and penetrance.

Adolescent↗
PubMed1976

Lymphocyte markers in newborn infants.

Purified peripheral blood lymphocytes from 20 newborn infants and 12 adults have been studied for the presence of surface markers. Adults and infants did not differ in the percentage of sheep RBC-binding cells (means 58-65%) or in Ig-bearing cells measured by the mixed antiglobulin reaction (means 7.2-11.6%). However, newborn infants had a significantly lower percentage of lymphocytes binding Fc of IgG (mean 10.4%) as compared to adults (mean 17.2%). No overall correlation between plasma Ig levels and Ig-bearing lymphocytes was found but a single infant with increased plasma IgA also showed the highest level of Ig-bearing lymphocytes among all infants.

Adult↗
PubMedDate not supplied

An improved procedure for N- to C-directed (Inverse) solid-phase peptide synthesis.

A method for solid-phase peptide synthesis in the N- to C-direction that delivers good coupling yields and a low degree of epimerization is reported. The optimized method involves the coupling, without preactivation, of the resin-bound C-terminal amino acid with excess amounts of amino acid tri-tert-butoxysilyl (Sil) esters, using HATU as coupling reagent and 2,4,6-trimethylpyridine (TMP, collidine) as a base. For the amino acids investigated, the degree of epimerization was typically 5%, except for Ser(t-Bu) which was more easily epimerized (ca. 20%). Five tripeptides (AA(1)-AA(2)-AA(3)) with different properties were used as representative model peptides in the development of the synthetic method: Asp-Leu-Glu, Leu-Ala-Phe, Glu-Asp-Val, Asp-Ser-Ile, and Asp-D-Glu-Leu. The study used different combinations of HATU and TBTU as activating agents, N, N-diisopropylethylamine (DIEA) and TMP as bases, DMF and dichloromethane as solvents, and cupric chloride as an epimerization suppressant. The epimerization of AA(2) in the coupling of AA(3) was further reduced in the presence of cupric chloride. However, the use of this reagent also resulted in a decrease in loading onto the resin and significant cleavage between AA(1) and AA(2). Experiments indicated that the observed suppressing effect of cupric chloride on epimerization in the present system merely seemed to be a result of a base-induced cleavage of the oxazolone system, the key intermediate in the epimerization process. Consequently, the cleavages were most pronounced in slow couplings. An improved synthesis of fully characterized amino acid tri-tert-butoxysilyl (Sil) ester hydrochloride building blocks is presented. The amino acid Sil esters were found to be stable as hydrochlorides but not as free bases. Although only a few peptides have been used in this study, we believe that the facile procedure devised herein should provide an attractive alternative for the solid-phase synthesis of short (six residues or less) C-terminally modified peptides, e.g., in library format.

Combinatorial Chemistry Techniques↗
PubMedDate not supplied

Phospholipid metabolism of A-cell enriched pancreatic islets.

Glucose exerts different effects on the hormone secretion from pancreatic B- and A-cells. In order to assess whether this can be linked to a difference in the effects of glucose on the phospholipid metabolism of these two cell types, islets were isolated from streptozotocin-treated (A-cell enriched islets) or normal guinea-pigs (B-cell rich islets). A-cell enriched islets contained more phospholipids when correction was made for the difference in size. Glucose-stimulated (16.7 mM) phospholipid and diacylglycerol biosynthesis, as estimated from 14C-glucose incorporation, was somewhat more stimulated in normal islets as compared with that of A-cell enriched islets. Triacylglycerol biosynthesis was, however, stimulated to the same extent. The pattern of 14C-glucose incorporation into the different phospholipid classes was very similar in both kinds of islets. Despite their smaller size, A-cell enriched islets incorporated, however, as much 14C-glucose as normal islets into most phospholipid classes. The present results are in line with previous findings of differences in glucose handling between the two cell types.

Animals↗