Core fucosylation of high-mannose-type oligosaccharides in GlcNAc transferase I-deficient (Lec1) CHO cells

During studies on the fucosylation of endogenous proteins in parental (Pro5) and N-acetyl-D-glucosamine (GlcNAc) transferase I-deficient (Lec1) Chinese hamster ovary (CHO) cells, we observed that Lec1 cells incorporate approximately 10-fold less [3H]fucose into macromolecules than Pro5 cells. Interestingly, most of the labelled oligosaccharides from both cell types could be released from the macromolecules by digestion with peptide N-glycosidase F (PNGase F). This was unexpected for Lec1 cells because they do not synthesize complex- or hybrid-type N-glycans. Structural analyses of the fucosylated oligosaccharides from Lec1 cells showed the fucose to be in an alpha 1,6 linkage to the core GlcNAc of relatively small oligomannose N-glycans (Man4GlcNAc2 and Man5GlcNAc2, where Man is D-mannose). Comparing the sizes of oligomannose N-glycans from Pro5 and Lec1 cells demonstrated a much higher proportion of the small (Man4GlcNAc2 and Man5GlcNAc2) oligomannose species in Lec1 cells. These results suggest that the core alpha 1,6 fucosyltransferase will fucosylate small (Man4-Man5GlcNAc2), but not large (Man8-Man9GlcNAc2) oligomannose N-glycans.     

Shoulder kinematics with two-plane x-ray evaluation in patients with anterior instability or rotator cuff tearing

There is still a significant lack of treatment and rehabilitation facilities for chronic pain patients in Germany today. Most of all the treatment of low back pain and widespread pain syndromes or panalgesia is time consuming and complicated. The main problem of anaesthesiological pain clinics is the increase of these complex pain syndromes in the last years. The definition of chronic pain is a continuous noxious input modulated and compounded by the prolonged or recurrent nature of chronic state and further complicated by a multitude of economic and psychosocial factors. It is now clear that no one discipline or mode will suffice. Only a multidisciplinary and intensive approach will prevail, as discussed in this article. Unfortunately these multidisciplinary pain units are nearly not existing in Germany just as little as control of the effectiveness of pain treatment.     

Investigations into the nature of a 7-OH-DPAT discriminative cue: comparison with D-amphetamine

In the present study, separate squads of rats were trained to discriminate either the dopamine D3 receptor preferring ligand 7-hydroxy-2-(di-N-propylamino)-tetralin (7-OH-DPAT) (0.03 mg/kg) from saline, or D-amphetamine (0.3 mg/kg) from saline using a standard operant schedule (FR10 schedule reinforcement). Following stable acquisition of responding, tests of generalisation and antagonism were conducted. A number of dopamine agonists having high dopamine D2-like receptor (D2, D3 or D4) affinity generalised to the 7-OH-DPAT, but not amphetamine, cue. The dopamine D2/3 receptor agonist SKF38393 showed no generalisation to either drug cue. Subsequent correlational analysis suggested that this effect was most likely mediated through the dopamine D3 receptor. The dopamine D2/3 receptor antagonist raclopride significantly attenuated both cues. The failure of these drugs to generalise to amphetamine, suggest that there is little involvement of the dopamine D3 receptor subtype in mediating its discriminative stimulus properties.     

SociaL aspects of pulmonology

A group of new-onset pulmonary tuberculosis patients has been studied and its social characterization is provided in the paper. Comparison of the 1991-1992 findings with those obtained in 1970-1980 has indicated that social aspects are topical as before and have some specific features in recent years. The most important issues are now living conditions, financial status of the patients, their social lifestyle, refugees and rational employment of tuberculosis patients and disabled persons.     

Response of frog and toad skin to norepinephrine

Maintenance of a hydrated integument is essential to the normal function of amphibian skin, and amphibians have developed mechanisms to minimize cutaneous dessication. The present work was conducted on skins of amphibians exhibiting a clear preference for either of two such mechanisms to study the influence of such mechanisms on the characteristics of epithelial transport. The response to norepinephrine (NE) was studied in isolated skins of a semiaquatic frog (Leptodactylus chaquensis), known to maintain indispensable skin moisture by secreting a superficial film of mucus via sympathetic stimulation of skin glands, and a terrestrial toad (Bufo arenarum), which replenishes a superficial film of fluid by drawing soil water upward by capillarity. In L. chaquensis skin, NE 5.0 x 10(-7) M, induced slow onset, sustained increases in short-circuit current (SCC) and transepithelial conductance, which were abolished by amiloride, a specific sodium transport inhibitor. At 1.2 x 10(-5) M, the response to NE exhibited a faster onset and a shorter time course. The SCC response also became insensitive to amiloride and could thus be induced by exposing the skin to NE in the presence of the inhibitor. The response was also greatly reduced in the absence of chloride, strongly suggesting a greater dependence on the glandular secretory response. In B. arenarum skin, the response to NE was far more sensitive to amiloride, regardless of the concentration of NE used. Induction of a response in the amiloride-blocked skin required a 10-fold higher concentration of NE, and the resulting effect was still considerably smaller than that observed in the skin of L. chaquensis after the same treatment. The number of mucous glands per unit area in B. arenarum skin was found to be around one-fifth of that observed in L. chaquensis, thus in part explaining the difference in the magnitude of the responses. The response of the skin of L. chaquensis to NE in the presence of sulfate was found to be consistent with the postulated involvement of frog skin glands in sulfate excretion. In contrast, this function was not evident in the skin of B. arenarum. The pattern of response of B. arenarum skin to all concentrations of NE tested closely resembles that seen after exposure to agents known to activate a cyclic AMP-dependent, high-permeability Cl pathway previously described by us in the skin of the toad. Our observations underscore the physiological differences existing in skins from different species, particularly regarding the relative importance of the glandular component of transport.     

The effects of a high fat diet on leptin mRNA, serum leptin and the response to leptin are not altered in a rat strain susceptible to high fat diet-induced obesity

Osborne-Mendel (OM) and S5B/Pl rats differ in their sensitivity to develop obesity when fed a high fat (HF) diet; OM rats become obese, whereas S5B/Pl rats remain thin. We have investigated the possibilities that either an impaired leptin response or resistance to leptin action underlies the sensitivity to this form of obesity in OM rats. In Experiment 1, OM and S5B/Pl rats fed a nonpurified diet were killed at d 0 or were fed either a HF (56% fat energy) or a low fat (LF, 10% fat energy) diet for 2 or 7 d. The HF diet increased serum leptin significantly by d 2 to levels that were similar in both rat strains. At 7 d, leptin levels were lower than at d 2 but remained higher than levels in the d 0 control groups. The leptin mRNA:18S RNA ratio in epididymal adipose tissue increased to higher levels in HF-fed OM rats than in S5B/Pl rats fed that diet. However, although the LF diet had no effect in S5B/Pl rats, it increased leptin mRNA levels in epididymal adipose tissue of OM rats compared with the controls fed the nonpurified diet. In Experiment 2, OM and S5B/Pl rats were fed HF or LF diets for 5 wk. At that time, their feeding response to a range of leptin doses (0, 1, 5 or 10 microgram) given intracerebroventricularly was tested after overnight food deprivation. There was a similar dose-dependent reduction in energy intake in response to leptin in both OM and S5B/Pl rats. These responses were independent of the diet. The data suggest that the susceptibility of OM rats to HF diet-induced obesity is not related to either a loss of central sensitivity to leptin or a failure to enhance leptin production acutely, although the failure to maintain chronically increased levels of serum leptin could contribute to the obesity.