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Biomedical subjects

K Lundin

Publications and source records attributed to K Lundin.

48 records · Page 3Linked to original sources

A specific assay measuring binding of 125I-Gp 120 from HIV to T4+/CD4+ cells.

The HIV (HTLV-III) envelope glycoprotein, Gp120, was isolated from virus-infected tissue culture cells using affinity chromatography. A radioimmunoassay was developed to determine the degree of iodinated Gp120 to target CD4+ (T4+) cells. 125I-Gp120 could be shown to selectively bind to CD4+ cells only. The Gp120 remained bound to these cells after repeated washes. Monoclonal anti-CD4 antibodies block the binding of Gp120 to CD4+ cells. Monoclonal antibodies to other cell surface components do not interfere with 125I-Gp120 binding. All IgG antibodies from HIV seropositive donors tested block 125I-Gp120 binding, though with variable titers. We believe that this assay provides further proof for the use of CD4 (T4) as a component of the receptor for HIV. It represents a safe, objective and sensitive method for the analysis of Gp120-CD4 interactions, as well as the potential of antibodies to interfere with this binding.

Antibodies, Monoclonal↗

Genomic HLA-DQ beta polymorphism associated with insulin-dependent diabetes mellitus. Analysis of possible functional significance.

Twelve insulin-dependent diabetes mellitus (IDDM) patients and healthy controls, who all carried the serologically defined DR3 and DR4 antigens, were compared with respect to other HLA polymorphisms. No significant differences between patients and controls were found by typing for HLA-Dw determinants by homozygous cell typing, nor by studies of their genomic DR beta polymorphism using different restriction enzymes. In contrast, certain DR beta polymorphism using different restriction enzymes. In contrast, certain DR4-associated genomic DQ beta fragments had a significantly different distribution among the IDDM patients than among the controls. Furthermore, when the distribution of all DQ beta-specific fragments which demonstrated polymorphism in our material was taken into account, nine of the 12 DR3, 4 IDDM patients demonstrated a similar DQ beta polymorphism compared with only two out of the 12 DR3, 4 controls (P = 0.006; corrected P = 0.037). Cells from patients and controls who demonstrated this IDDM-associated DQ beta polymorphism stimulated each other significantly less in reciprocal MLC tests, compared with the responses seen when their cells were confronted with cells from the DR3, 4 individuals with other genomic DQ beta polymorphisms.

Adult↗

The effect of drugs used in anticoagulation therapy on T lymphocyte activation in vitro. II. Warfarin inhibits T lymphocyte activation.

The effect of warfarin on T lymphocyte activation in vitro was investigated. Warfarin was found to cause a dose-dependent inhibition of both antigen- and PHA-stimulated proliferation. The drug had to be present during the early steps in T lymphocyte activation to cause inhibition. Warfarin seemed to have no effect on antigen processing or presentation. Warfarin inhibited Interleukin 2 (IL-2) production, but had only minimal effects on expression of IL-2 receptors or IL-2 dependent proliferation. The inhibition in most in vitro models was found only at warfarin concentrations exceeding the therapeutic serum level.

Antigens, Viral↗

The effect of drugs used in anticoagulation therapy on T lymphocyte activation in vitro. I. Heparin inhibits activation by soluble antigen or allogeneic cells but not by phytohaemagglutinin.

Heparin in concentrations corresponding to the therapeutic serum level (0.5 IU/ml) was found to inhibit proliferative responses in MLC and antigen (mumps)-stimulated cultures. Heparin had to be present early during culture to exert this effect. Heparin did not inhibit antigen-induced expression of IL-2 receptors. No inhibition was seen when heparin was present only during antigen pulsing of antigen-presenting cells. Heparin had no effect on PHA-stimulated proliferation, IL-2 production or expression of IL-2 receptors. Heparin also inhibited the IL-2 dependent growth of long-time cultured T cell lines. The inhibitory effects of heparin were not caused by a toxic effect on the cells.

Antigens, Viral↗

Neuropeptides in the gastrointestinal canal of Necturus maculosus. Distribution and effects on motility.

The presence and distribution of regulatory peptides in nerves and endocrine cells of the stomach, intestine and rectum of a urodele amphibian, the mudpuppy, Necturus maculosus, was studied immunohistochemically in sections or whole-mount preparations of the gut wall. The effect of the occurring peptides on gut motility was studied in isolated strip preparations of circular and longitudinal smooth muscle from different parts of the gut. Bombesin-, neurotensin-, substance P- and VIP-like immunoreactivity was present in abundant nerve fibres in the myenteric plexus of both stomach, intestine and rectum. Single fibres or bundles were present in the circular muscle layer and in a well-developed deep muscular plexus in the intestine and rectum. Immunoreactive nerve cells were found in the myenteric plexus of the stomach, intestine (neurotensin only) and rectum. Gastrin/CCK-like immunoreactivity was observed only in a few fibres in stomach and rectum. Endocrine cells containing bombesin-, met-enkephalin-, gastrin/CCK-, neurotensin-, somatostatin- or substance P- like immunoreactivity were present in the mucosa. The effect of bombesin was an inhibition of the rhythmic activity in circular muscle preparations and in longitudinal muscle from the rectum, while longitudinal muscle from the stomach usually responded with a weak increase in tonus. Neurotensin, like-bombesin, was inhibitory on the spontaneous rhythmic activity of circular muscle throughout the gut, while the effect on longitudinal muscle was an increase in tonus. Met-enkephalin and substance P increased the tonus of all types of preparations, and often, in addition, initiated a rhythmic activity superimposed on this maintained tonus. VIP had a general inhibitory effect on the preparations, decreasing tonus and/or abolishing rhythmic activity. It is concluded that bombesin-, neurotensin-, substance P- and VIP-like peptides are present in nerves throughout the urodele gut and may have physiological functions in regulating the motility of the gut. The gastrin/CCK-like peptide present in nerves of the stomach and rectum may affect the function of these parts of the gut. The regulatory peptides present in endocrine cells may, perhaps with the exception of the somatostatin-like peptide, affect the motility humorally.

Animals↗

Distribution of lymecycline in interstitial fluid and paranasal sinus mucosa. An experimental and clinical study.

A comparison between different methods of determining the levels of lymecycline in tissue is presented. The drug levels have been compared with those registered, during the steady state condition, in interstitial fluid obtained from subcutaneously implated tissue cages in rabbits. The 'tissue piece diffusion method' developed is reproducible; it allows antibiotic levels to be determined in minute pieces of tissues, and it seems to measure the total diffusable drug in the interstitial fluid phase. This method was employed in the analyses of lymecycline concentrations in the maxillary sinus mucosa in 12 patients, and it demonstrated a good penetration into the tissue. The level reached was well above the Minimal Inhibitory Concentration of most bacteria causing maxillary sinusitis.

Animals↗

Secretory otitis media. Aspects on treatment and control.

In a double-blind study, 228 secretory otitis media patients were evaluated according to mucolytic and decongestive treatment. No definite difference comparing with the placebo group was registered. About 50% of all patients were cured within 4 weeks after the diagnosis was established. Those patients who earlier had been treated with antibiotics because of a preceding acute otitis media had a better cure rate than the untreated group. Suggestions on treatment and control of secretory otitis media are given.

Anti-Bacterial Agents↗

Ciliary ultrastructure of polyplacophorans (Mollusca, Amphineura, Polyplacophora).

This study is part of a series of papers aiming to investigate the phylogenetic significance of ciliary ultrastructure among molluscs and to test the hypothesis of a relationship between Xenoturbella and the molluscs. The ultrastructure of the ciliary apparatus on the gills of the polyplacophorans Leptochiton asellus and Tonicella rubra was studied. The gill cilia of the two species are similar in shape. The free part of the cilium is long with a slender distal part. There are two ciliary rootlets. One of them is short, broad and placed on the anterior face of the basal body. The other rootlet is conical and has a vertical orientation. Among the mollusca, two ciliary rootlets in the ciliary apparatus of multiciliate ectodermal cells have only been reported from the Chaetodermomorpha and Neomeniomorpha. This character state is likely plesiomorphic for the Mollusca and indicates a basal (nonderived) position of these taxa among the molluscs. No possible synapomorphic character with Xenoturbella bocki was found.

Animals↗