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Biomedical subjects

L Langer

Publications and source records attributed to L Langer.

At least 19 recordsLinked to original sources
PubMed2006

Hyperfine spectrum of RbCl.

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of the four isotopomers of RbCl. Coupling constants for the nuclear electric quadrupole interactions, the spin-rotation interactions, the tensor and scalar spin-spin interactions, and a rubidium nuclear octupole interaction, and their dependence on vibrational and rotational states have been determined. The dominant interaction, the rubidium nuclear electric quadrupole interaction, shows a small shift with substitution of the chlorine isotope.

Journal Article↗
PubMed1996

Microheterogeneity of the hydrophobic and hydrophilic part of the glycosylphosphatidylinositol anchor of alkaline phosphatase from calf intestine.

Digestion of calf intestine alkaline phosphatase with pronase and subsequent dephosphorylation of the released peptidyl-(Etn-P)2-glycosyl-PtdIns with HF generated 8 glycosyl-Ins species the largest of which (G1 and G2) have the following proposed structures: [sequence: see text] G3 and G5 are lower homologues of G1 and G2, respectively, being one alpha 1-2 linked mannopyranosyl residue shorter. G4 is analogous to G2 lacking the N-acetylgalactosaminyl residue and G6 is the next lower homologue of G4. Most of G4 and G6 occur substituted with a palmitoyl (G4, G6) or a myristoyl residue (G6) probably attached to the inositol moiety. Thus, the basic ManxGlc-Ins species are either substituted with an N-acetylgalactosaminyl residue or a fatty acid ester. The structures were deduced from compositional analysis, molecular-mass determination by matrix-assisted laser desorption MS, sequential hydrolysis with appropriate exoglycosidases and treatment with CrO3. Purification of the glycosylinositol species was achieved by a novel reverse-phase HPLC technique using fluorescent fluoren-9-yl-methoxy-carbonyl (Fmoc) derivatives. These stable derivatives were susceptible to hydrolysis with exoglycosidases which allowed sequential cleavages to be carried out and kinetics to be followed at the picomole level. We observed recently that native alkaline phosphatase separates on octyl-Sepharose into four distinct fractions of increasing hydrophobicity (F1-F4). Here we show that all four fractions contain G1-G6. The acylated species G4 and G6 were restricted to F2 and F4 which had been shown earlier to contain, on average, 2.5 and 3 fatty acid residues/subunit, respectively. In all four fractions the diradylglycerol moiety was predominantly diacylglycerol, alkylacylglycerol being less than 10% which is in contrast to most glycosyl-PtdIns--anchored proteins of mammalian origin.

Acetylgalactosamine↗
PubMed1994

Enhancing cosmetics through regenerative periodontal procedures.

Patients' desire for more esthetic smiles has prompted the development of periodontal regenerative techniques. Case reports of periodontal therapy in the form of subepithelial connective-tissue grafts and socket retention for problems such as deformed ridges, exposed root surfaces and uneven smile lines will be presented in this article.

Alveolar Ridge Augmentation↗
PubMed1993

Uncoupling of beta 1-adrenoceptors from cardiac adenylyl cyclase in cardiomyopathic and control hamsters.

The beta-adrenoceptor-adenylyl cyclase system was studied in heart ventricles from Wistar rats, cardiomyopathic (BIO 8262) and nonfailing control hamsters (CLAC) using the beta 1-adrenoceptor antagonist CGP 20712A. In radioligand binding studies, the majority of beta-adrenoceptors in ventricles from rats as well as from CLAC hamsters was of the beta 1-subtype (72.2% and 76.6%, respectively). In BIO ventricles a significant (CLAC vs. BIO, P < 0.05) reduction in the beta 1-subtype (62.9%) was found. In Wistar rats the subtype-mediated stimulation of adenylyl cyclase reflected the beta 1:beta 2 ratio as determined by binding studies. In hamster ventricles the effect of isoprenaline was mediated predominantly (CLAC) or exclusively (BIO) via the beta 2-subtype, indicating that cardiac beta 1-adrenoceptors were partly (CLAC) or completely (BIO) uncoupled from the adenylyl cyclase.

1-Methyl-3-isobutylxanthine↗
PubMed1993

Angel-shaped phalango-epiphyseal dysplasia (ASPED): identification of a new genetic bone marker.

We describe a "new" mild malformation of the phalanx, which we call the "angel-shaped phalanx" (ASP) because of its resemblance to the little angels used for the decoration of Christmas trees. A particular middle phalangeal type of ASPs is found in a distinct variety of multiple epiphyseal dysplasia with marked retardation of bone age and severe coxarthrosis in adult life, previously reported as "hereditary peripheral dysostosis" [Bachman, 1967: Proc R Soc Med 60:21-22; Giedion, 1969: Fortschr Rontgenstr 110:507-524]. However, these authors overlooked the unique configuration of the middle phalanges. We renamed the condition "angel-shaped phalango-epiphyseal dysplasia (ASPED)", which may be transmitted in an autosomal-dominant manner. Six new patients are added, bringing the total to nine patients (two families and two isolated patients). ASPs were seen in five of six children. The ASPs grew into inconspicuous brachydactyly after physeal closure (3/3). The most important additional radiological finding is late and dysplastic development of both femoral heads (5/5), leading to Perthes-like and osteoarthritic changes and severe hip pain in the early thirties (2/2 adults, having reached this age). The marked retardation of carpal bone age may lead to unnecessary clinical evaluation for endocrine disorders. Less frequent clinical manifestations of ASPED are hyperextensibility of the interphalangeal joints (7/9) and hypodontia (4/7). Other types of ASPs are observed in brachyphalangy type C, spondylo-megepiphyseal-metaphyseal dysplasia, and other conditions. The concept of mild bone abnormalities as specific markers for genetic disease, as with cone-shaped epiphyses and now evident in ASPED, may also be useful for ASPs in general.

Adolescent↗
PubMed1993

Beta-adrenoceptor density and subtype distribution in cerebellum and hippocampus from patients with Alzheimer's disease.

beta-Adrenoceptor density and beta 1- and beta 2-subtype distribution were examined in hippocampi and cerebella from patients with Alzheimer's disease (AD/SDAT). Tissues from age-, sex and post-mortem delay matched non-demented patients served as controls. The total beta-adrenoceptor density as evaluated in saturation experiments with the hydrophilic radioligand [3H]CGP 12177 was higher in hippocampal (36-39 fmol/mg protein) than cerebellar tissues (20-21 fmol/mg), however, no differences were found in either brain region between AD/SDAT patients and controls. Subtype distribution using the highly selective beta 1-adrenoceptor antagonist CGP 20712A revealed a slightly higher proportion of beta 1-adrenoceptors in hippocampus (26%-27%) than in cerebellum (20%-21%) with, again, no difference between AD/SDAT and controls. We recently described a 40% reduction in basal and stimulated adenylyl cyclase activity in post-mortem hippocampus of AD/SDAT patients, a brain region greatly affected by the disease, the present data now demonstrate that this disease-related effect is not mirrored by a similar change in beta-adrenoceptor density nor in subtype distribution.

Adrenergic beta-Antagonists↗
PubMed1993

Thiazide-induced kidney damage with circulating antibodies against myeloperoxidase and cardiolipin.

A 79-year-old man developed a renal insufficiency while on thiazide. Extrarenal symptoms were absent. Screening for antibodies revealed high titre for anti-myeloperoxidase and anti-cardiolipin antibodies, but no other antibodies were present. After withdrawal of the drug the progression of renal insufficiency ceased. Four months later the both antibodies had disappeared. We conclude, that antibodies against granulocytes will become a valuable diagnostic tool in diagnosing drug-induced vasculitis.

Aged↗
PubMed1993

The wide fixture: a solution for special bone situations and a rescue for the compromised implant. Part 1.

This paper describes a new 5.0-mm-diameter self-tapping implant, a modification of the standard Brånemark fixture designed to increase the amount of bone-to-titanium surface contact and to capture dense bone at the lateral and crestal borders of the alveolus. Indications for its use include (1) areas of inadequate bone height, (2) areas of poor bone quality (type IV), and (3) immediate replacement of non-integrated or fractured implants. This preliminary report discusses the design alterations and surgical techniques available to treat these difficult bone situations.

Alveolar Bone Loss↗
PubMed1993

The subepithelial connective tissue graft for treatment of gingival recession.

A technique has been described for areas of single or multiple root coverage, especially in the maxilla, for coverage of existing crown margins, and for areas requiring a combination of ridge augmentation and root coverage. The success of the subepithelial connective tissue graft is attributed to the double blood supply at the recipient site from the underlying connective tissue base and the overlying recipient flap. The donor site is a closed wound, which produces less postoperative discomfort. In addition, an excellent color blend can be achieved.

Connective Tissue↗
PubMed1986

The accuracy of hysterosalpingography versus laparoscopy in evaluation of infertile women.

Two hundred fifteen infertile women underwent hysterosalpingography (HSG) and laparoscopy. One hundred twenty-eight patients had bilaterally patent tubes on hysterosalpingography. Thirty-one percent of these women had pelvic adhesions diagnosed by laparoscopy. Eighty-seven women had either occluded tubes or suspected pelvic adhesions on hysterosalpingography. Thirty-nine percent of these women had patent tubes without any pelvic pathology on laparoscopy. Inaccurate diagnoses limit the value of hysterosalpingography in evaluation of tubal and peritubal pathology.

Adult↗