Biomedical subjects

L Yan

Publications and source records attributed to L Yan.

At least 217 records · Page 12Linked to original sources

PubMed1996

Experimental study on microthrombi and myocardial injuries.

The experiment was conducted with SD male rats. After they had been each given an intravenous injection of high molecular weight dextran (0.8 ml/100 g body wt) once a day for 4 days, they were brought under the observation of ECG and mesentery microcirculation. Microthrombi were found in the venules and capillaries of each rat of the experimental group, while in the microcirculation of the control group rats, no microthrombi were found. No changes were found in the ECGs of the rats (n = 6) in the control group after the injections, while the rats in the subject group all suffered a rise in the S-T segment of ECG, an indication of myocardial injuries. The rise was significantly in positive correlation to the increase in microthrombi in number (r = 0.944, P < 0.01). The erythrocytes of the rats in the subject group clustered to become rouleau-like, and platelets aggregated by tens and hundreds to form microthrombi. Their blood also showed a significant decrease in number of platelets. The degree of platelet aggregation and the scores of the rise on ECG were significantly in positive correlation as shown by the results: y = 20 + 94x, r = 0.94, P < 0.01. The plasma TXB2 of the subject group increased obviously but the change of 6-K-PGF1 alpha in the blood was not significant. The content of plasma TXB2 and the scores that indicated the rise in the S-T segment of the ECG showed significantly a positive correlation by the analysis of linear regression equation: y = 109.997 +/- 116.25x, r = 0.889, P < 0.05. The activity of Na(+)-K(+)-ATPase on the myocardial cell membranes of the rats with microthrombi was significantly reduced as compared with that of the rats in the control group (P < 0.01). The activity of the Na(+)-K(+)-ATPase was significantly in negative correlation to the rise in the S-T segment of ECG (P < 0.05). This study demonstrates that the above changes are the causes of myocardial injuries in rats with circulatory thrombi.

6-Ketoprostaglandin F1 alpha↗

PubMed1996

Local immune response in Helicobacter pylori-infected cats and identification of H. pylori in saliva, gastric fluid and faeces.

Helicobacter pylori-infected cats were screened by culture and polymerase chain reaction (PCR) for the presence of H. pylori in salivary secretions, gastric juice, gastric tissue and faeces. H. pylori was cultured from salivary secretions in six of 12 (50%) cats and from gastric fluid samples in 11 of 12 (91%) cats. A 298 base pair polymerase chain reactions (PCR) product specific for an H. pylori 26000 MW surface protein was amplified from dental plaque samples from five of 12 (42%) cats and from the faeces of four of five (80%) cats studied. Analyses of serum and mucosal secretions by enzyme-linked immunosorbent assay (ELISA) revealed an H. pylori-specific immunoglobulin G (IgG) response, and elevated IgA anti-H. pylori antibody levels in salivary and local gastric secretions. Immunohistochemical analyses of gastric tissue revealed the presence of IgM+ B cells assembled into multiple lymphoid follicles surrounded by clusters of CD4+ and CD8+ T cells. The lamina propria also contained single cells or aggregates of IgA+ and IgM+ B cells. These observations show that H. pylori can be identified in feline mucosal secretions, and that a localized IgA immune response develops in gastric tissue of H. pylori-infected cats. The findings suggest a zoonotic risk from exposure to personnel handling H. pylori-infected cats in vivaria.

Animals↗

PubMed1996

The effect of long-term calcium supplementation on indices of iron, zinc and magnesium status in lactating Gambian women.

The effect of long-term supplementation with CaCO3 on indices of Fe, Zn and Mg status was investigated in a randomized, double-blind intervention study of sixty lactating Gambian women. The supplement contained 1000 mg Ca and was consumed between meals 5 d/week, for 1 year starting 1.5 weeks postpartum. Compliance was 100%. Plasma ferritin concentration, plasma Zn concentration and urinary Mg output were measured before, during and after supplementation at 1.5, 13, 52 and 78 weeks postpartum. No significant differences in mineral status were observed at any time between women in the supplement and placebo groups. Analysis of the longitudinal data series showed that plasma ferritin and Mg excretion were characteristic of the individual (P < 0.001). Within individuals, ferritin concentration was higher at 1.5 weeks postpartum than later in lactation (P = 0.002). Plasma Zn concentration was lower at 1.5 weeks postpartum than at other times (P < 0.001), an effect which disappeared after albumin correction. Low plasma concentrations of ferritin and Zn indicated that the Gambian women were at high risk of Fe and Zn deficiency. Measurements of alpha 1-antichymotrypsin suggested that the results were not confounded by acute-phase responses. The results of the present study indicate that 1000 mg Ca as CaCO3 given between meals does not deleteriously affect plasma ferritin and Zn concentrations or urinary Mg excretion in women who are at risk of Fe and Zn deficiency.

Adolescent↗

PubMed1996

Synthetic peptides derived from the sequence of human C-reactive protein inhibit the enzymatic activities of human leukocyte elastase and human leukocyte cathepsin G.

Peptides derived from the primary sequence of the acute phase reactant C-reactive protein (CRP) are shown to inhibit in vitro the enzymatic activities of human leukocyte elastase (hLE) and human leukocyte cathepsin G (hCG), which are associated with tissue damage occurring in the course of several chronic inflammatory conditions. CRP-derived peptides were synthesized based on their sequence similarity to domains within the natural inhibitors of hLE and hCG. The octapeptide Val89-Thr-Val-Ala-Pro-Val-His-Ile96 (CRP 89-96) is shown to inhibit hLE and hCG to a larger extent than peptides of similar chain lengths corresponding to the active sites of their natural inhibitors, alpha 1-protease inhibitor and alpha-antichymotrypsin, respectively. Several additional peptides containing this core sequence were synthesized and shown to be inhibitors, in contrast to peptides derived from other regions of CRP as well as the intact protein, which are totally inactive. The inhibitory capability of CRP-derived peptides, which may be generated in vivo by neutrophil-mediated proteolysis as part of a complex regulatory homeostatic mechanism, may now be used as a basis for the design of novel therapeutic substances. The present finding may shed some light on the enigmatic physiological functions of CRP.

C-Reactive Protein↗

PubMed1996

Natural and experimental Helicobacter mustelae reinfection following successful antimicrobial eradication in ferrets.

BACKGROUND: Recrudescence or reinfection may occur after eradication of Helicobacter pylori in humans. MATERIALS AND METHODS: We used the ferret Helicobacter mustelae model to investigate the effect of prior infection and eradication on reinfection by experimental and natural routes. Two groups of ferrets with naturally acquired H. mustelae infection were treated with an eradication protocol using amoxicillin, metronidazole, and bismuth subsalicylate. The ferrets were monitored for recrudescence by repeated cultures of endoscopic gastric mucosal biopsies. The ferrets were challenged at 17 months (group I) and 6 months (group II) after eradication with a strain of H. mustelae having a distinctive restriction endonuclease analysis pattern. The eradication protocol was repeated to eliminate the infection produced by experimental challenge. The ferrets were then cohoused intermittently with naturally infected ferrets. RESULTS: The original H. mustelae infection was successfully eliminated by the eradication protocol. No recrudescence was observed in group I for 12 months nor for 3 months in group II after eradication. All ferrets became persistently reinfected with the challenge strain. The infection from the challenge strain was eradicated successfully. No ferrets in group I and all ferrets in group II became infected through cohousing. CONCLUSIONS: These results suggest that though prior infection with H. mustelae may confer some protection against reinfection, such protection is not universal in all circumstances; that susceptibility to reinfection by contact with infected animals varies between individuals; and that age may be a factor in this individual variability. These results are applicable to studies of reinfection after eradication of H. pylori in humans.

Amoxicillin↗

PubMed1996

An apparent functional correlation between variations in amino acid residues in HLA-DR4.1 and 4.2 serological subtypes and oligonucleotide characterization.

HLA-DR4 can be subdivided serologically into two specificities, DR4.1 and DR4.2, using well-defined monospecific alloantisera used in the 11th International Histocompatibility Workshop. In this study, a total of 1095 random DR4-positive individuals from several ethnic groups were tested first for serotype DR4.1/4.2 and then for DRB1*04 alleles using polymerase chain reaction (PCR) followed by sequence-specific oligonucleotide probe hybridization (SSOPH). An almost 100% correlation between samples testing positive for DR4.1 and the presence of alanine at position 74 was observed, while samples testing positive for DR4.2 correlated with the presence of glutamic acid at position 74. DRB1*04 alleles 0401, 0402, 0404, 0405, 0408, 0409 and 0410 are aligned in functional groups which coincide with the serological subtype of DR4.1. DRB1*04 alleles 0403, 0406, 0407 and 0411 coincide with subtype DR4.2. Amino acid substitutions at positions 57, 71 and 86 indicate other significant variations between alleles within the serological subgroup of DR4.1 and define five minor subgroups. The serologic and oligonucleotide allelic subgroups are in turn correlated with recognized cellular Dw antigens. While sequence data provide evidence of structural differences, data on cellular antigens support a functional association between these designated groups and their significance in transplantation and GVHD. Testing results are categorized by ethnic group in order to establish frequency data for donor selection criteria.

Amino Acid Sequence↗

PubMed1996

Chronic proliferative hepatitis in A/JCr mice associated with persistent Helicobacter hepaticus infection: a model of helicobacter-induced carcinogenesis.

Helicobacter hepaticus causes hepatitis in selected strains of mice and in A/JCr mice is linked to liver cancer. To analyze whether H. hepaticus persists in specified ecological niches, to determine whether biomarkers of infection exist, and to analyze the influence of H. hepaticus on hepatocyte proliferation, a longitudinal study of H. hepaticus-infected A/JCr mice was undertaken. A/JCr mice were serially euthanatized from 3 through 18 months and surveyed by enzyme-linked immunosorbent assay; bacterial culture of liver, colon, and cecum; histology; electron microscopy; hepatocyte proliferation indices determined by using 5-bromo-2'-deoxyuridine; and measurement of the liver enzyme alanine aminotransferase. In infected animals throughout the 18-month study, H. hepaticus was consistently isolated from the lower bowel but only sporadically from the liver. By electron microscopy, H. hepaticus was noted infrequently and only in bile canaliculi. Infected mice, particularly males, showed chronic inflammation; oval cell, Kupffer cell, and Ito cell hyperplasia; hepatocytomegaly; and bile duct proliferation. The inflammatory and necrotizing lesion was progressive and involved the hepatic parenchyma, portal triads, and intralobular venules. Hepatic adenomas were noted only in male mice, whereas 5-bromo-2'-deoxyuridine proliferation indices were markedly increased in both sexes, but especially in males, compared to control A/J mice. Infected mice also developed sustained anti-H. hepaticus serum immunoglobulin G antibody responses and elevated alanine aminotransferase levels. H. hepaticus, which persists in the lower bowels and livers of A/JCr mice, is associated with a chronic proliferative hepatitis, and hepatomas in selected male mice indicate that this novel bacterium may cause an increased risk of hepatic cancer induction in susceptible strains of mice. This murine model should prove useful in dissecting the molecular events operable in the development of neoplasms induced by bacteria belonging to this expanding genera of pathogenic Helicobacter species.

Alanine Transaminase↗

PubMed1996

Persistent hepatitis and enterocolitis in germfree mice infected with Helicobacter hepaticus.

Helicobacter hepaticus has been associated with naturally occurring hepatitis in certain inbred strains of mice, and in A/JCr mice it has been linked to the development of hepatic adenomas and adenocarcinomas. H. hepaticus was orally inoculated into 30 axenic, outbred female mice, and the mice were studied longitudinally to fulfill Koch's postulates and to ascertain the pathogenic potential of the organism under defined germfree conditions. Ten cage contact mice were also housed in the same germfree isolator to study transmission patterns, and 10 germfree mice were maintained in separate isolators as controls. Mice serially euthanized from 3 weeks through 24 months postinoculation (p.i.) were surveyed by culture and PCR for H. hepaticus in liver and intestinal tissues. Tissues were analyzed for histopathological changes, and sera were assayed for the presence of immunoglobulin G antibody to H. hepaticus and changes in the liver enzyme alanine aminotransferase. Inoculated mice and cage contact mice were persistently infected with H. hepaticus as identified by culture and PCR, in both the intestine and, less frequently, the liver, for the duration of the 2-year study. Animals developed persistent chronic hepatitis, and in some animals enterocolitis was noted. Hepatocellular carcinoma was diagnosed in one H. hepaticus-infected mouse. The level of H. hepaticus serum antibody was highest in experimentally infected mice at 12 to 18 months p.i.; this corresponded in general to the time interval when the highest levels of alanine aminotransferase were recorded. Although cage contact mice became persistently infected with H. hepaticus, lesions were less severe and the levels of serological biomarkers utilized in the study were lower. The H. hepaticus-infected mouse will provide an ideal model to study putative bacterial virulence determinants and how they interact with the host to induce chronic inflammation and tumorigenesis.

Animals↗

PubMed1996

Helicobacter canis isolated from a dog liver with multifocal necrotizing hepatitis.

On the basis of biochemical, phenotypic, and 16S rRNA analysis, a novel gram-negative bacterium, isolated from normal and diarrheic dogs as well as humans with gastroenteritis, has been recently named Helicobacter canis. A 2-month-old female crossbred puppy was submitted to necropsy with a history of weakness and vomiting for several hours prior to death. The liver had multiple and slightly irregular yellowish foci up to 1.5 cm in diameter. Histologically, the liver parenchyma contained randomly distributed, occasionally coalescing hepatocellular necrosis, often accompanied by large numbers of mononuclear cells and neutrophils. Sections of liver stained by the Warthin-Starry silver impregnation technique revealed spiral- to curve-shaped bacteria predominantly located in bile canaliculi and occasionally in bile ducts. Aerobic culture of liver was negative, whereas small colonies were noted on Campylobacter selective media after 5 days of microaerobic incubation. The bacteria were gram negative and oxidase positive but catalase, urease, and indoxyl acetate negative; nitrate was not reduced to nitrite, and the organism did not hydrolyze hippurate. The bacteria were also resistant to 1.5% bile. Electron microscopy revealed spiral-shaped bacteria with bipolar sheathed flagella. By 16S rRNA analysis, the organism was determined to be H. canis. This is the first observation of H. canis in active hepatitis in a dog and correlates with recent findings of Helicobacter hepaticus- and Helicobacter bilis-related hepatic disease in mice. Further studies are clearly warranted to ascertain whether H. canis-associated hepatitis is more widespread in canines as well as a cause of previously classified idiopathic liver disease in humans.

Animals↗

PubMed1996

Clonality assays and megakaryocyte culture techniques in essential thrombocythemia.

The development of techniques permitting in vitro growth of human megakaryocytes progenitors and more recently identification of the proto oncogene c-mpl (Mpl-R) and its ligand (Mpl-L) have created new opportunities for studying pathophysiology of E.T. Plasma or serum of E.T. patients was unable to overestimulate MK colony formation by normal bone marrow cells. Significant increases in circulating CFU MK in E.T. patients have been repeatedly observed while in E.T. marrow, due to inappropriate sampling, colony number was not significantly different from normal. Spontaneous colony formation is observed in approximately 100% bone marrow and 85% blood from E.T. patients. Spontaneous colony formation persisted in plasma clot assay without added plasma or serum and in serum free agar cultures but only at a slightly lower rate than in plasma clot. Spontaneous colony formation in culture condition without plasma and serum were never observed with normal bone marrow and blood. Spontaneous MK growth was observed in a higher proportion of E.T. patients than erythroid colony formation but both phenomenon can occur in about 50% of the patients. CFU MK colony formation disappeared in serum free cultures using highly purified CD 34 cells. MK development is not completely independent of regular control. An hypersensitivity of E.T. MK progenitors to growth factors known to stimulate normal hematopoiesis (IL3.IL6, GM CSF, has been shown as well as a decreased sensitivity to negative regulators (TGF beta), has been suggested. The number of spontaneous MK colonies was not significantly decreased by added anti IL3, IL6 or anti GM CSF, antibodies in culture medium. Pre incubation of blood non adherent mononuclear cells of E.T. patients with antisense oligonucleotides to c-mpl significantly decreased the cloning efficiency of spontaneous megakaryocyte growth as compared to the introduction of scrambled oligomers. Finally m RNA expression of the Mpl-L (TPO) was not formed in MK spontaneously grown in serum free liquid cultures after 12 days. These results suggest that human c-mpl proto oncogene may be implicated in the pathway of spontaneous megakaryocytopoiesis in MPD but an absence of autocrine-stimulation by TPO of spontaneous growth in MPD. Analysis of peripheral blood cell clonality was performed in 55 E.T. patients using either the DNA methylation pattern of the androgen receptor (AR) gene or mRNA transcripts of G6PD or IDS genes. 51 out of 55 patients were informative. Non random X inactivation was found on unfractioned blood in 73% as compared with 23% in normal females (skewed Lyonisation). In 12 patients monoclonality of hematopoiesis was definitely confirmed by recording polyclonality of the mononuclear fraction or of T lymphocytes. In 4 patients monoclonal hematopoiesis was limited to platelets, 7 patients remained polyclonal in whole blood and all cellular fractions studied. MK colony formation (provided that the serum free agar culture system is clearly standardised) and clonality studies on whole blood or granulocyte, T lymphocyte and platelet fractions may be proposed as positive criteria for diagnosis of E.T.

Bone Marrow↗

PubMed1996

Inflammatory large bowel disease in immunodeficient mice naturally infected with Helicobacter hepaticus.

Large bowel disease detected clinically by rectal prolapse was studied in 64 immunodeficient mice (37 athymic NCr-nu/nu, 12 BALB/c AnNCr-nu/nu, 9 C57BL/6NCr-nu/nu, and 6 C.B17/Icr-scid/NCr) naturally infected with Helicobacter hepaticus. Rectal prolapse was found in approximately 5% of immunodeficient mice maintained in a research facility over a period of 3.5 years. All mice had various degrees of chronic proliferative typhlitis, colitis, and proctitis, usually without concomitant hepatitis. Some mice had severe proliferative proctitis with cystic hyperplasia. Histologic study of the large bowel of 48 athymic NCr-nu/nu mice without H. hepaticus infection and housed in another clean facility revealed only 12% of the mice with minimal-to-mild large bowel inflammation. Helicobacter hepaticus infection is associated with large bowel disease in immunodeficient mice but is not seen in H. hepaticus-infected immunocompetent mice. This new pathogenic bacterial infection should be considered as another potential cause or co-factor for rectal prolapse and large bowel disease in mice.

Animals↗

PubMed1996

Evaluation of various oral antimicrobial formulations for eradication of Helicobacter hepaticus.

Helicobacter hepaticus colonizes the cecum and colon of several strains of mice from a variety of commercial suppliers, persistently infects mice, causes chronic hepatitis, is linked to hepatic tumors in A/JCr mice, and has been associated with inflammatory bowel disease of athymic and scid mice. For this reason, eradication of the organism from infected mouse colonies is desirable. We recently reported that amoxicillin or tetracycline-based triple therapy (amoxicillin or tetracycline in combination with metronidazole and bismuth) given by oral gavage 3 times daily for 2 weeks eradicated H. hepaticus in 8- to 10-week-old A/JCr mice. To establish a more convenient therapy regimen for eradicating H. hepaticus, we evaluated water and dietary administration of various antibiotic combinations in A/JCr and DBA/2 mice naturally infected with H. hepaticus. The A/JCr male mice received amoxicillin-based triple therapy in drinking water or by oral gavage, or received tetracycline-based triple therapy in the drinking water. The DBA/2J female mice received amoxicillin-based triple therapy in a specially formulated dietary wafer or by oral gavage, or received enrofloxacin in drinking water. All treatments were given for a 2-week period. Control animals received no treatment. One month after treatment, H. hepaticus was recovered from the liver, cecum, or colon of A/JCr control mice and mice receiving amoxicillin- or tetracycline-based triple therapy in drinking water but not in mice receiving amoxicillin-based triple therapy by oral gavage. Helicobacter hepaticus was not recovered from DBA/2J mice receiving amoxicillin-based triple therapy in dietary wafer or by oral gavage but was recovered from control mice and 7 of 10 mice receiving enrofloxacin in drinking water. Results indicate that amoxicillin-based triple therapy administered in the diet or by oral gavage is effective in eradicating H. hepaticus. Antibiotics administered in the water, however, were not effective in eradicating the organism.

Administration, Oral↗

PubMed1996

Aggregation of phospholipid vesicles induced by the ribosome inactivating protein saporin.

Saporin-S6(SO-6) is a single chain ribosome inactivating protein, which can inhibit protein synthesis by inactivating eukaryotic ribosomes. The interaction of SO-6 with phospholipid model systems was described. SO-6 can specifically interact with negatively-charged phospholipid vesicles and it induces the aggregation of the lipid vesicles. The kinetics of the vesicle aggregation induced by SO-6 was studied. The saturating protein/lipid molar ratio was determined to be 1:100 based on titration experiments. The aggregation is dependent on the temperature in a range that was many times higher than the phase transition temperature of the phospholipid. The effect of pH on the aggregation of the vesicles can not be explained by simple deprotonation of side chain amino groups of the protein, and may be related to conformational changes of the protein. The maintenance of physiological ionic strength was required for the aggregation of SO-6 with vesicles. Finally, the interaction was prompted by Ca2+ ions, and was totally inhibited by EDTA, which suggests that SO-6 may interact with phospholipid vesicles in a Ca(2+)-dependent manner.

Calcium↗

PubMed1996

Prevention of disability and rehabilitation--results from a collaborative project in China.

Eight different geographical districts in China varying in urban and rural characteristics from 6 provinces and 2 municipalities were selected as pilot areas of the project. The interventions included early detection and treatment of neuritis, self-care training, adapted footwear, surgery, comprehensive treatment of complicated ulcers, and prostheses. Main changes in eye, hand and foot impairments between baseline assessment and assessment at 2 years have been presented in this paper.

China↗

PubMed1996

[Experimental study on repair of mandibular defect by allogenic decalcified bone compounded with autogeneic bone marrow in rabbits].

Twenty adult rabbits were used in our experiment. The bone defects were made at the lower border of the bilateral mandible. A compound bone graft (allogenic decalcified bone with autogeneic bone marrow, ADB) was implanted in the right bone defect as the experimental group. The left mandible was taken as the control group and autogeneic cancellous bone was grafted. The process of new bone formation was evaluated by X-ray plain film, 99Tc-PYP Scintigraphy, histological, and histochemical, and transmmission electronic microscope examinations. The results demonstrated histogically that ADB induced new bone formation. The quantity of new bone produced by compound bone graft in the experimental group was much more than that in control group (P < 0.05). The compound bone graft can promote and accelerate bone defect healing.

Animals↗

PubMed1996

[Radioembolization with 32P-labelled glass microspheres for advanced hepatocellular carcinoma].

We evaluated the efficacy and side effect of 32P-Labelled glass microspheres (32P-GMS) as a radioembolizer for patients with advanced hepatocellular carcinoma (HCC). 24 patients with unresectable HCC received internal radiation treatment of 32P-GMS. The tumor size varied from 3.6 to 18 cm. Hepatic arterial embolization was carried out through intraoperative or Seldinger's method. The mean absorbed radiation dose of the liver was 3250 rad (range from 1200 rad to 8000 rad). The radiation intensity within the tumor was 3.3 times stronger than in liver tissue. Not significant bone marrow renal toxicity was noted within 1 to 3 months. > 50% of tumor shrinkage was found in 17 cases, and < 50% of tumor reduction in 5 cases. The cumulative survival rate of 3, 6, 12, 18, 24 months was 92%, 75%, 54%, 33% and 29%. Hepatic arterial instillation of 32P-GMS appears to be safe and effective for unresectable HCC even with portal vein thrombosis.

Adult↗

PubMed1995

Tandem mass spectrometry analysis of synthetic opioid peptide analogs.

Five synthetic opioid peptides that were designed to have specific opioid receptor-binding properties were studied by low energy collision-induced dissociation (CID) tandem mass spectrometry (MS/MS). The MS/MS data are required for the analysis of those peptides in ovine plasma in a study to determine the placental transfer of the peptide to the fetus. The synthetic enkephalin-related peptides were: Tyr-D-Arg-Phe-Lys-NH2, (DALDA), N,N-diallyl-Tyr-Aib-Aib-Phe-Leu-OH, (ICI 174,864), Tyr-D-Thr-Gly-Phe-Leu-Thr, (DTLET), Tyr-D-Pen-Gly-Phe-D-Pen-OH, (DPDPE), and D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2, (CTAP). Liquid secondary ion mass spectrometry (LSIMS) was used for sample desorption-ionization, and a hybrid (E1BE2qQ) tandem mass spectrometer was used to collect the product-ion spectra. A protonated molecule ion, [M + H]+, was observed for each peptide. Amino acid sequence-determining fragment ion were produced by CID and collected by MS/MS for the three linear peptides, and also for the two disulfide-bond-containing peptides in their unreduced and dithiothreitol (DTT)-reduced forms. The detection level for the [M + H]+ ion of DTLET was ca. 3 pmol; and the stabilities of the CTAP and ICI analogs in plasma were studied.

Acetylation↗

PubMed1995

Assessing the level of student reflection from reflective journals.

The concept of reflective learning has been widely adopted in many of the nursing curricula today. Reflective learning is of particular relevance to the education of professionals, as it encourages students to integrate theory with practice, appreciate the world on their own behalf, and turn every experience into a new potential learning experience. While nurse educators have widely accepted the educational benefits of reflection, research into reflective learning is hampered by the lack of reliable and widely accepted methods for assessing whether reflection takes place and the level of any reflection. This study attempted to develop and test coding systems for written reflective journals based on two well-known models of reflective thinking. The reflective journals submitted by the students were subjected to content analysis at two levels. The findings of this study suggest that student writing can be used as evidence for the presence or absence of reflective thinking. The process of allocating students to three categories of non-reflector, reflector and critical reflector was straightforward and reliable. Identifying textual elements within journals and allocating them to the finer levels of reflection within a more complex model of reflective thinking was, however, more problematic and considerably less reliable.

Autobiographies as Topic↗