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Biomedical subjects

S Ritter

Publications and source records attributed to S Ritter.

At least 55 records · Page 3Linked to original sources
PubMed1999

Recording skills practice on videotape can enhance learning - a comparative study between nurse lecturers and nursing students.

Video recording techniques have been used in educational settings for a number of years. They have included viewing video taped lessons, using whole videos or clips of tapes as a trigger for discussion, viewing video recordings to observe role models for practice, and being video recorded in order to receive feedback on performance from peers and tutors. Although this last application has been in use since the 1960s, it has only been evaluated as a teaching method with health care professionals in the past 10 years and mostly in the areas of medical and counsellor education. In nurse education, however, use of video recording techniques has been advocated without any empirical evidence on its efficacy. This study has used nursing degree students and nurse educationalists to categorize statements from four cohorts of students who took part in a 12-day clinical supervision course during which their interpersonal skills were recorded on videotape. There were two categories: positive and negative/neutral. Analysis of the data showed that between 61% and 72% of the subjects gave an overall positive categorization to the statements in the questionnaire. Chi-square tests were significant for all groups in both categories. This suggests that both nursing students and nurse lecturers thought that course participants' statements expressed a positive belief that video tape recording is useful in enhancing students' ability to learn effective interpersonal skills in clinical supervision.

Adult↗
PubMed1999

A national survey of practice nurse involvement in mental health interventions.

BACKGROUND: The move in the United Kingdom (UK) from institutional to community care has led to an inevitable increase in the involvement of practice nurses (PNs) in mental health care. Around 20 000 PNs are currently working in the United Kingdom (UK). However, the extent and nature of PN involvement in delivering mental health interventions has not been adequately explored. AIM: This study aimed to quantify practice nurses' involvement in delivering mental health interventions in primary care settings. METHOD: A questionnaire was sent to a random sample of 1500 practice nurses registered with the Practice Nurse Forum at the Royal College of Nursing. Sixty per cent of questionnaires were returned; however, once non-eligible respondents were removed an adjusted response rate of 54% was achieved. RESULTS: Practice nurses play a significant role in the assessment and treatment of mental health problems, most frequently via the administration of depot antipsychotics and the screening for depression. However, antipsychotic side-effects were infrequently monitored and PNs' understanding of treatment issues in depression is poor. These findings may be associated with the reported lack of mental health training that PNs have received. CONCLUSIONS: The findings of this study have important implications for the training of practice nurses in mental health, specifically in the areas of medication management and the detection of mental disorders.

Adult↗
PubMed1999

RBE for carbon track-segment irradiation in cell lines of differing repair capacity.

PURPOSE: The LET position of the RBE maximum and its dependence on the cellular repair capacity was determined for carbon ions. Hamster cell lines of differing repair capacity were irradiated with monoenergetic carbon ions. RBE values for cell inactivation at different survival levels were determined and the differences in the RBE-LET patterns were compared with the individual sensitivity to photon irradiation of the different cell lines. MATERIAL AND METHODS: Three hamster cell lines, the wild-type cell lines V79 and CHO-K1 and the radiosensitive CHO mutant xrs5, were irradiated with carbon ions of different energies (2.4-266.4 MeV/u) and LET values (13.7-482.7 keV/microm) and inactivation data were measured in comparison to 250 kV x-rays. RESULTS: For the repair-proficient cell lines a RBE maximum was found at LET values between 150 and 200 keV/microm. For the repair-deficient cell line the RBE failed to show a maximum and decreased continuously for LET values above 100 keV/microm. CONCLUSIONS: The carbon RBE LET relationship for inactivation is shifted to higher LET values compared with protons and alpha-particles. RBE correlated with the repair capacity of the cells.

Animals↗
PubMed1998

Subgroups of hindbrain catecholamine neurons are selectively activated by 2-deoxy-D-glucose induced metabolic challenge.

Glucose is a major fuel for body energy metabolism and an essential metabolic fuel for the brain. Consequently, glucose deficit (glucoprivation) elicits a variety of physiological and behavioral responses crucial for survival. Previous work indicates an important role for brain catecholamine neurons in mediation of responses to glucoprivation. This experiment was conducted to identify the specific catecholamine neurons that are activated by glucoprivation. Activation of hindbrain catecholamine neurons by the antimetabolic glucose analogue, 2-deoxy-D-glucose (2DG; 50, 100, 200 or 400 mg/kg, s.c.) was evaluated using double label immunohistochemistry. Fos protein was used as the marker for neuronal activation and the enzymes tyrosine hydroxylase (TH) and phenethanolamine-N-methyl transferase (PNMT) were used as the markers for norepinephrine (NE) and epinephrine (E) neurons. 2-Deoxy-D-glucose (200 and 400 mg/kg) produced selective activation of distinct hindbrain catecholamine cell groups. In the ventrolateral medulla, doubly labeled neurons were concentrated in the area of A1/C1 and were predominantly adrenergic in phenotype. In the dorsal medulla, doubly labeled neurons were limited to C2 and C3 cell groups. In the pons, some A6 neurons were Fos-positive. Neurons in rostral C1, ventral C3, A2, A5 and A7 did not express Fos-ir in response to 2DG. Our results identify specific subpopulations of catecholamine neurons that are selectively activated by 2DG. Previously demonstrated connections of these subpopulations are consistent with their participation in the feeding and hyperglycemic response to glucoprivation. Finally, the predominant and seemingly preferential activation of epinephrine neurons suggests that they may play a unique role in the brain's response to glucose deficit.

Adrenal Glands↗
PubMed1998

Galanin injection into the nucleus of the solitary tract stimulates feeding in rats with lesions of the paraventricular nucleus of the hypothalamus.

Feeding can be stimulated by injection of galanin into the area postrema/nucleus of the solitary tract (AP/NTS) or fourth ventricle (4V). However, the threshold for galanin-induced feeding is lower when galanin is injected into the paraventricular nucleus of the hypothalamus (PVN) than when injected into the NTS. The greater apparent sensitivity of the PVN to galanin and the proximity of this nucleus to the third ventricle raise the possibility that galanin injected into the AP/NTS or 4V may stimulate feeding by accessing receptors in the PVN rather than by a local action in the hindbrain. To assess this possibility, feeding in response to NTS galanin was evaluated in rats with bilateral electrolytic lesions of the PVN. We found that PVN lesions did not abolish feeding induced by injections of galanin into the NTS. Rather, galanin-induced feeding, but not mercaptoacetate- or 2-deoxy-D-glucose-induced feeding, was significantly enhanced in PVN-lesioned rats compared to sham-operated controls. These results suggest that galanin receptors in the NTS region mediate feeding in response to galanin and that the galaninergic nerve terminals innervating these receptors may originate in part from cell bodies in the PVN.

Animals↗
PubMed1998

Comparison of sperm viability with seminal plasma metal levels.

This study compares the semen levels of lead (Pb), cadmium (Cd), and aluminum (Al) in relation to live sperm in semen samples from 64 apparently healthy men. The measured levels were separated into live sperm count tertiles (<25% [18 subjects], 25-50% [26 subjects], and >50% [20 subjects]). The mean +/- SD for each group was calculated, and the difference between the means of the high and low tertiles were compared by ANOVA. Significant differences were observed between the high and low live sperm groups for Pb (p < 0.01) and Al (p < 0.05), but not Cd. Spearman's rank correlation between sperm viability and the semen plasma metal levels showed a direct relation to Mg (p < 0.05). However, there was an inverse relation to lead (p < 0.001), cadmium (p < 0.01), and aluminum (p < 0.01). There was no significant correlation between Ca and Zn. Linear regression between the live sperm counts and semen level of the three metals show that metal levels were inversely correlated with the percentage of live sperm (p < 0.001, < 0.01). Apparently, the presence of these metals in the environment and in seminal plasma exerts a toxic effect on sperm.

Adult↗
PubMed1998

Induction of chromosomal damage in CHO-K1 cells and their repair-deficient mutant XRS5 by X-ray and particle irradiation.

The cytogenetic effects of X-rays and Au ions were investigated in repair-proficient CHO-K1 cells and their radiosensitive mutant strain xrs5, which shows a defect in the rejoining of DNA double-strand breaks. Both cell lines were synchronized by mitotic shake off, irradiated in G1-phase with either 250 kV X-rays or 780 MeV/u Au ions (LET: 1150 keV/micrometer) and chromosome aberrations were analyzed in first post-irradiation metaphases. Isoeffective doses of X-rays for the induction of aberrant cells and aberrations per cell were about 14 times lower for xrs5 than for CHO-K1 cells. After high LET radiation the difference in the cytogenetic response of both cell lines was drastically diminished. Furthermore, the analysis of the aberration types induced by sparsely and densely ionizing radiation showed for both cell lines specific changes in the spectrum of aberration types as LET increases. The experimental results are discussed with respect to the different types of lesions induced by sparsely and densely ionizing radiation.

Animals↗
PubMed1998

Analysis of chromosome damage based on the time course of aberrations.

PURPOSE: To describe a method for the analysis of radiation induced chromosome aberrations which will in particular be suitable for the comparison of different radiation qualities. The method is applied to previously published data. METHODS: The basic idea of the approach is to use the time-course of aberrations up to the time when all cells have passed through first mitosis. Instead of comparing data obtained at a single sampling time, the number of aberrant cells or aberrations is integrated over several sampling times. The integral represents a measure of the total fraction of cells showing aberrations and the total amount of aberrations induced in the irradiated cell population. In addition, a correction factor is applied which takes into account the dilution of heavily damaged cells at late sampling times by cell division of undamaged or less severely damaged cells. RESULTS AND CONCLUSIONS: Previously published data on the induction of chromosome aberrations by 4.6 MeV/u Ar ions and X-rays are re-analysed using the new approach. It is demonstrated that this method allows a better comparison of experiments using extremely different radiation qualities and consequently different cell cycle perturbations.

Animals↗
PubMed1998

Bladder control a consequence of maturation: evidence after renal transplantation.

This report contains case studies on three children with early end-stage renal failure due to renal malformation or nephrotic syndrome, but without bladder involvement. All patients became anuric in the second year of life, before having obtained bladder control. They underwent successful cadaveric renal transplantation, having been anuric for almost 2 to 4 years. When the bladder catheter was removed 5 days after transplantation, all three children asked for the urine potty without ever having been prompted. Three weeks after transplantation, all three children achieved complete bladder control during the day, and two of them also at night. These observations add further evidence to the notion that the development of bladder control is a consequence of maturation and not of training.

Female↗
PubMed1998

Particle-induced chromosome aberrations and mutations: an overview.

Energy depositions by sparsely and densely ionizing radiation in the cellular DNA are responsible for deleterious radiobiological effects like the induction of chromosome aberrations or gene mutations. However, due to differences in the spatial pattern of energy deposition the action of densely ionizing radiation is quantitatively and qualitatively different from that of sparsely ionizing radiation. By the use of new molecular-biological techniques a deeper insight into the molecular events underlaying particle-induced genetic changes has been obtained. The present paper will attempt to give a brief overview of progress in chromosome and mutation studies, Furthermore, recent published data on delayed genetic effects of cellular exposure to ionizing radiation will be summarized.

Animals↗
PubMed1998

Manganese superoxide dismutase (MnSOD) and autoantibodies against MnSOD in acute viral infections.

Sera of 146 patients with acute EBV, HAV, HBV, CMV, HSV, and rubella virus infections, and sera from 35 healthy controls were tested for the antioxidant enzyme manganese superoxide dismutase (MnSOD). An enzyme immunoassay that detects all isomeres of the enzyme was developed. The mean MnSOD value of healthy controls was 107 ng/ml. In HAV, HBV and EBV infections characterized by viral replication in internal organs, there was an average 5-fold rise of serum MnSOD, whereas in viral infections with low direct cytopathogenity, such as rubella, CMV and HSV, the MnSOD levels showed only minor rises. These sera were also tested for autoantibodies against MnSOD using a novel sensitive indirect enzyme immunoassay. The average IgM anti-MnSOD concentration in sera of healthy controls was 112 GU. In sera of patients with acute HBV, CMV, HSV or rubella virus infections IgM anti-MnSOD values were only slightly raised above the cut-off level. In contrast, in some patients with acute EBV infections anti-MnSOD concentrations rose up to 20-fold of normal values. In HAV infections the same phenomenon was observed in patients who had reactivated EBV infections. These findings indicate that EBV may facilitate the B-cell response to MnSOD. These autoantibodies may inhibit the protective function of MnSOD and prolong the disease by oxygen injury. Our concept on the pathogenic effect of the autoantibodies against MnSOD emphasizes the importance of the antioxidant enzyme in viral infections.

Acute Disease↗
PubMed1997

Aqueduct occlusion does not impair feeding induced by either third or fourth ventricle galanin injection.

Exogenous galanin stimulates feeding when injected into forebrain and hindbrain sites, including the third and fourth ventricles (3V and 4V), amygdala, paraventricular nucleus of the hypothalamus (PVN), and nucleus of the solitary tract (NTS). Because the PVN and NTS border the ventricular space, it is possible that feeding stimulated by injection of galanin at these sites may be caused by the transport of galanin through the ventricular system to a remote site of action. The role of ventricular transport of galanin between the 3V and 4V in galanin-induced feeding was examined in this study. Rats were implanted with two guide cannula assemblies: one dorsal to the mesencephalic aqueduct and the other in the 3V or 4V. Feeding in response to 3V or 4V galanin injection was first measured after sham-occlusion of the aqueduct. Subsequently, flow of cerebrospinal fluid between the forebrain and hindbrain ventricles was acutely interrupted by injection of a silicone grease plug into the mesencephalic aqueduct just before assessment of the feeding response to 4V or 3V galanin injection. Aqueduct occlusion did not alter the feeding induced by either 3V or 4V galanin injection, indicating that galanin terminals in both the diencephalon and hindbrain are involved in control of food intake.

Animals↗
PubMed1997

Crystallization and preliminary X-ray diffraction data of two different human low-density lipoprotein (LDL) subfractions.

Human LDL subfractions LDL-2 (d = 1.031-1.034 g/ml) and LDL-5 (d = 1.040-1.044 g/ml) were crystallized in two different crystal forms by using polyethylene glycol as a precipitant. Both fractions were from one donor. Crystals of LDL-5 were yellow, hexagonal, and showed no dichroism. Crystals of LDL-2 were of the same color, had a rodlike shape with notches at both ends, and were highly dichroitic. LDL-2 crystals diffracted to a resolution of 29 A by using synchrotron radiation. Indexing in P1 resulted in preliminary parameters for the reduced cell of a = 171 A, b = 438 A, c = 519 A, alpha = 102 degrees, beta = 99 degrees, gamma = 91. These dimensions are consistent with the size of LDL particles. Using Fourier transform infrared spectroscopy (FTIR) and agarose gel electrophoresis, we could further confirm that the crystals consist of LDL. The FTIR spectrum showed bands characteristic for lipids and protein. Dissolved crystals exhibited a mobility similar to native LDL in agarose gels and could be stained with anti-human apolipoprotein B (apoB).

Crystallization↗
PubMed1996

Haemolysis in hepatitis A virus infections coinciding with the occurrence of autoantibodies against triosephosphate isomerase and the reactivation of latent persistent Epstein-Barr virus infection.

Haemolysis has been observed frequently as a complication of acute hepatitis A virus (HAV) infection. However, the pathogenic mechanism has not been elucidated completely. In individual cases the detection of anti-erythrocyte antibodies of unknown specificity was described. The raised serum IgM fraction was shown to consist partially of autoantibodies. Previously, we detected autoantibodies of immunoglobulin class M directed against triosephosphate isomerase (IgM anti-TPI) in patients with infectious mononucleosis. These autoantibodies are able to induce haemolysis. In this study the occurrence of IgM anti-TPI in acute HAV infections and other viral diseases has been investigated. In 33 of 134 patients suffering from HAV infection (IgM anti-TPI was detected. Haematological and chemical data were available from seven of these 33 patients. Mild-to-moderate signs of haemolysis correlating with the IgM anti-TPI titre in the follow-up examinations were demonstrated. The presence of IgM anti-TPI in HAV infections is connected with a reactivation of a latent persistent EBV infection. In other viral infections both the detection of IgM anti-TPI and evidence of a reactivated EBV infection is rare. Thus, we anticipate that IgM anti-TPI antibodies occurring with the reactivation of a latent persistent EBV infection take part in provoking haemolysis in acute HAV infections.

Autoantibodies↗