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Biomedical subjects

C Morgan

Publications and source records attributed to C Morgan.

At least 73 records · Page 4Linked to original sources
PubMed1998

Nurses performing embryo transfer: the development and results of the Birmingham experience.

Although in-vitro fertilization treatment is doctor-led, many of its steps are performed by nurses. The embryo transfer step, however, is performed exclusively by doctors in the majority of units. In our unit, doctors performed embryo transfers from June 1994 until December 1995 (period I). From January 1996 until May 1997 (period II) the nurses, after appropriate training, performed the procedure. When they experienced difficulties during the mock transfer performed immediately before the real transfer, or if they were not available to do the procedure, a doctor performed it. In period I, 488 embryo transfers were performed (all by doctors), with a pregnancy rate per transfer of 35% and an implantation rate of 16%. In period II, 522 embryo transfers were performed. Nurses performed 371 (71%) and doctors 151 (29%) of the procedures. The pregnancy rate per nurse-transfer was 40.2% and per doctor-transfer 41%. The corresponding implantation rates were 16.9% and 17%. None of these differences were statistically significant (P > 0.05). These data indicate that, with appropriate training and medical back-up, nurses can perform the majority of embryo transfers with ease and outcome comparable to that of doctor embryo transfer.

Embryo Implantation↗
PubMed1998

Laminin blocks the assembly of wild-type A beta and the Dutch variant peptide into Alzheimer's fibrils.

Amyloid fibril formation is believed to be a nucleation-dependent polymerization process which may be influenced by various other factors with important consequences for the development, prevention or treatment of amyloidosis. We have previously shown that laminin inhibits A beta peptide fibril formation in vitro. Here we present a kinetic study that indicates laminin to be a potent anti-amyloidosis factor, as it not only inhibited A beta 1-40 fibril aggregation, but also inhibited the aggregation of the Dutch A beta 1-40 variant, a peptide with a higher capacity to aggregate than the wild-type A beta 1-40. The inhibitory effect of laminin on amyloid fibril formation was not overcome by the addition of pre-formed A beta fibrils, suggesting that laminin inhibits the fibril elongation process. At the present time, however, we cannot rule out the possibility that laminin also affects the initial nucleation process of A beta fibril formation. On other hand, laminin was not able to counteract the amyloid fibril formation promoted by acetylcholinesterase (AChE), another component of the amyloid deposits found in AD brains. The effect of laminin may be important as an inhibitor of A beta amyloidogenesis in vivo, specifically at the level of cerebral blood vessels.

Acetylcholinesterase↗
PubMed1997

Managing admissions. Bed spreads.

A decrease in surgical beds left a trust insufficient flexibility to increase an already high throughput without affecting the quality of care. Changes in the management of surgical admissions, including the appointment of an admissions co-ordinator, have improved co-ordination of elective and emergency admissions. Three years later maximum waiting times had fallen from 18 to 10 months. In the first nine months of the new booking system, the number of operations cancelled on the day because of bed nonavailability fell by half, while patients cancelled on the day of admission dropped by 36 per cent.

Admitting Department, Hospital↗
PubMed1997

Isolation and characterization of a new member of the scavenger receptor superfamily, glycoprotein-340 (gp-340), as a lung surfactant protein-D binding molecule.

We have purified a previously unknown glycoprotein (designated gp-340) from human bronchioalveolar lung washings from a patient with alveolar proteinosis. gp-340 was identified by its calcium-dependent binding to lung surfactant protein D (SP-D) and by its molecular mass of 340 kDa in the reduced state on SDS-polyacrylamide gel electrophoresis (PAGE). gp-340 was purified from the 10,000 x g pellet of the lavage fluid by ion-exchange and gel permeation chromatography. On SDS-PAGE, gp-340 showed an apparent molecular mass of 290 kDa in the unreduced state. On gel chromatography under non-dissociating conditions, the apparent molecular mass of gp-340 was >1000 kDa. The presence of N-linked glycosylation was shown by digestion with N-glycosidase F, which reduced the apparent molecular mass of gp-340 under reducing condition to about 300 kDa. Partial amino acid sequence data showed the presence of scavenger-receptor type domains. Monoclonal and polyclonal antibodies were raised against gp-340, and their specificities were confirmed by Western blotting. The antibodies were used for immunohistochemical localization of gp-340 in the lung, where it was found on the surface of and within alveolar macrophages. Direct binding between gp-340 and SP-D took place at physiological ionic strength, required the presence of calcium, and was not inhibited by maltose. The binding between SP-D and mannan also required the presence of calcium, but this interaction was completely inhibited by maltose. The same binding pattern was seen between gp-340 and recombinant human SP-D composed of the trimeric neck region and three carbohydrate recognition domains. These findings indicate that the binding between gp-340 and SP-D is a protein-protein interaction rather than a lectin-carbohydrate interaction and that the binding to gp-340 takes place via the carbohydrate recognition domain of SP-D. We conclude that gp-340 is a new member of the scavenger-receptor superfamily and likely to be a truncated form of a receptor for SP-D.

Amino Acid Sequence↗
PubMed1997

Stability of empty and peptide-loaded class II major histocompatibility complex molecules at neutral and endosomal pH: comparison to class I proteins.

The structure and thermal stability of empty and peptide-filled forms of the murine class II major histocompatibility complex (MHC) molecule I-E(k) were studied at neutral and mildly acidic pH. The two forms have distinct circular dichroic spectra, suggesting that a conformational change may accompany peptide binding. Thermal stability profiles indicate that binding of peptide significantly increases the thermal stability of the empty heterodimers at both neutral and mildly acidic pH. Free energies calculated from these data provide a direct measure of this stabilization and show that the empty form of I-E(k) is significantly more stable than that of class I MHC proteins. Furthermore, for the two MHC class II proteins that were analyzed (I-E(k) and I-A(d)), thermal stability was not significantly altered by acidification. In contrast, of four class I MHC molecules studied, three have shown a significant loss in complex stability at low pH. The marked stability exhibited by their empty form, as well as their resistance to low pH, as observed in this study, correlate well with the ability of class II MHC molecules to traverse and bind peptides in acidic endosomal vesicles.

Amino Acid Sequence↗
PubMed1997

Sleep disorders in children with congenital anophthalmia and microphthalmia.

PURPOSE: The increased incidence of sleep disorders among blind patients has been documented in the sleep medicine literature. Blind patients lack the normal regulatory control of retinal input over their circadian rhythms, which can lead to abnormalities in their sleep-wake cycles. Our study was conducted to determine the incidence of sleep disorders in children with anophthalmia or microphthalmia and to offer therapeutic alternatives. METHODS: A 13-question survey was distributed to families of children with anophthalmia, microphthalmia, or both identified through the Anophthalmia/Microphthalmia Registry in Philadelphia, Pennsylvania. The survey included questions regarding the children's medical and ocular histories and any sleep disorders they may have experienced. Questions regarding daily schedules, family history, and social history were also included. RESULTS: Surveys were returned from 13 children with bilateral anophthalmia or microphthalmia. Ten of 13 (77%) anophthalmic/microphthalmic children were reported to have frequent early-morning waking and extensive daytime sleeping. Specific medical and social problems did not appear to be associated with the development of these sleep disorders. Strict daily schedules were often helpful in entraining the children's sleep-wake cycles. CONCLUSION: Without the contribution of retinal input to help regulate circadian rhythms, most children with bilateral anophthalmia or microphthalmia will experience sleep disorders. These children may benefit from the introduction of strict daily schedules, medical therapy (melatonin), or both. An attempt should also be made to preserve any existing light perception.

Anophthalmos↗
PubMed1997

Meal patterns of cats encountering variable food procurement cost.

The meal patterns of 2 cats in a laboratory habitat with variable foraging costs were examined in a foraging paradigm in which subjects could initiate meals at any time by completing a predetermined number of bar presses (the procurement price) and then could eat any amount. From meal to meal, the procurement price either was fixed or varied among a geometric series of five prices. As the fixed price or the mean of the variable prices increased, meal frequency decreased and meal size increased; daily intake was unaffected. Within variable-price schedules, meal size was not related to the just-paid procurement price. These results suggest that cats respond to the global rather than to the local cost structure of their habitat. They appear to respond to an average of the prices encountered, initiating meals of a frequency and size appropriate to that average. This was true even when the average price was high, meals were infrequent, and thus price encounters were widely separated in time. Therefore, the time window over which the consequences of behavior can affect behavior is longer than often conceived, at least in economies in which the animal controls its intake and the frequency, size, and distribution of its meals.

Animals↗
PubMed1997

Use of a modified version of the Overt Aggression Scale in the measurement and assessment of aggressive behaviours following brain injury.

Aggressive behaviour creates a significant challenge in neurorehabilitation. Despite the success in using behaviour modification principles in the treatment of post-acute behavioural problems, psychopharmacological approaches to the management of aggression are more frequently reported. However, inconsistencies apparent in the literature hinder inter-study comparisons of treatment methods. These include severity of brain injury, neuropsychological status and rigour of experimental methodology used. Data about aggression is also inconsistently reported, especially with regard to classification and severity. Descriptions of how aggressive behaviour responded to pre-treatment is also generally absent. In this paper an observational rating scale is described in an attempt to address these inconsistencies. The Overt Aggression Scale has been modified by increasing the range of interventions to reflect current practice in neurorehabilitation, and by changing the language to make it suitable for UK users. A range of antecedents has also been added to make the scale useful in behavioural analysis. Preliminary results indicate inter-rater reliability is good, and it is a valid indicator of type and severity of aggression. Antecedents and interventions used in the management of aggressive behaviours in neurorehabilitation are also illustrated. Clinical use of the scale is also discussed.

Aggression↗
PubMed1996

Laminin inhibits amyloid-beta-peptide fibrillation.

Laminin, an important extracellular matrix component is induced by brain injury and colocalizes with amyloid-beta-peptide (A beta) deposits in Alzheimer brains. We report here that laminin inhibits amyloid fibril formation as determined by thioflavin T fluorescence spectroscopy and electron microscopic examination. The inhibition of amyloid formation by laminin was concentration dependent and was observed at a laminin concentration of 300 nM, corresponding to a laminin/A beta protein molar ratio of 1:800. The potential effect of laminin, may prove important to inhibit A beta fibrillogenesis in vivo, specifically at the level of cerebral blood vessels.

Amyloid beta-Peptides↗
PubMed1996

The significance of microbial cultures of the hematopoietic support for patients receiving high-dose chemotherapy.

The use of hematopoietic support for patients receiving high-dose chemotherapy has increased over the past 10 years. Various quality controls are performed on the hematopoietic cells, including microbiologic cultures. There is considerable expense associated with the serial cultures performed at different times during the collection, processing, and use of the cells. We reviewed all the microbiologic cultures performed on bone marrow harvests and leukaphereses over a 17 month period. Of the 227 bone marrow harvests, 16 cultures were positive, but only 3 (1.3%) were repeat positives with the same organism after processing or at the time of reinfusion. Of the 560 leukaphereses, 4 (0.7%) were cultured positive at the time of collection and reinfusion. Two patients were bacteremic with gram-negative bacilli at the time of leukaphereses despite being asymptomatic, and these were the only two products that had to be collected again. No patient suffered an adverse clinical result after receiving culture-positive cells. Bone marrow and peripheral blood progenitor cells can be safely collected, and a culture after processing is adequate to ensure the safety of the product.

Blood↗