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Biomedical subjects

S Hughes

Publications and source records attributed to S Hughes.

At least 271 records · Page 15Linked to original sources
PubMedDate not supplied

Measurement of clozapine and norclozapine in plasma/serum by high performance liquid chromatography with ultraviolet detection.

A simple method for the measurement of clozapine and its N-desmethyl metabolite in human plasma or serum by high performance liquid chromatography is described. An internal standard (aqueous nortriptyline, 4 mg/L) (50 microL) and Tris buffer (2 mol/L, pH 10.6) (100 microL) are added to plasma/serum (200 microL) and the analytes and internal standard extracted into methyl tert-butyl ether (200 microL). The extracts are analysed on a 150 mm column containing Spherisorb S5SCX using methanol containing ammonium perchlorate (35 mmol/L, pH 6.7) as eluent at a flow rate of 1.5 mL/min. Detection is by ultraviolet absorption (215 nm). The limit of detection is better than 0.05 mg/L for both analytes and the intra-assay precision (CV) for clozapine and norclozapine was 5.3 and 7.3% at 0.5 mg/L and 2.6 and 2.8% at 1.5 mg/L, respectively. The method can be applied to the measurement of these compounds in plasma after acute overdosage, for the assessment of compliance in patients apparently refractory to therapy and to identify interactions between clozapine and other neuroleptic and antidepressant drugs which may effect toxicity.

Adult↗
PubMedDate not supplied

Pro-opiomelanocortin neuropeptide receptors on developing and dystrophic muscle fibers.

Autoradiography was used to investigate the presence of corticotropin and beta-endorphin receptors on soleus, extensor digitorum longus, and diaphragm muscles of normal and dystrophic adult mice and developing mice. In both adult and developing mice, specific binding sites for both [125I]ACTH and [125I]beta-endorphin were present in some fibers in all of the muscles examined. The specific binding sites appeared to be distributed over the length of the surface membrane in the fibers that expressed them. There were significantly higher proportions of fibers exhibiting the specific beta-endorphin and the specific ACTH binding sites in the three muscle types in mice of 5 d of age compared to the muscles of the normal adult. There was also a higher proportion of fibers with the putative ACTH and beta-endorphin receptors in the three muscle types in dystrophic mice.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

POMC-derived peptides in the neuromuscular system of streptozotocin-diabetic mice.

Immunoreactivity for beta-endorphin and alpha-MSH/ACTH was demonstrated in intramuscular nerves in soleus, extensor digitorum longus, and diaphragm muscles of normal and streptozotocin-diabetic mice. There was a higher incidence of immunoreactive nerves in the muscles of the diabetic mice. Specific binding for [125I]ACTH was detected in a proportion of the muscle fibers, using autoradiography. There were significantly more fibers with specific [125I]beta-endorphin sites and specific [125]ACTH sites in some muscles in the diabetic mice. The increased expression of POMC-derived peptides and their receptors in the neuromuscular system of streptozotocin-diabetic mice may indicate early neuropathic change.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Effect of IDPN on the expression of POMC-derived peptides in rat motoneurones.

Immunocytochemistry was used to detect beta-endorphin and alpha-melanotropin (alpha-MSH) in lumbar spinal motoneurones in rats treated with beta,beta'-iminodiproprionitrile (IDPN), a neurotoxicant that targets motoneurones or corn oil, which has no known neurotoxicity. After IDPN treatment most of the motoneurones were immunoreactive for both peptides but after corn oil treatment immunostaining was negligible. It is suggested that increased expression of the POMC-derived peptides may be part of the regenerative repertoire of the damaged motoneurone regardless of the cause of the lesion. Alternatively the peptides may simply accumulate in the motoneurones as a result of impaired axoplasmic transport.

Animals↗
PubMedDate not supplied

Relations between drawing cubes and copying line diagrams of cubes in 7- to 10-year-old children.

Previous research has suggested both links and differences between children's copying of line diagrams and their drawings of solid objects. If the diagram represents a familiar object, children make more errors than when copying a diagram of a nonobject or unfamiliar object, as if they are drawing from their representation of the object rather than copying the surface features of the diagram. However, copying a diagram yields fewer and different types of errors than drawing the equivalent solid, which suggests a different process. In Experiment 1 (n = 72), possible relations between copying and drawing are investigated by asking children to draw a solid cube, then to copy or trace a line diagram of the cube in oblique projection, and finally to draw the solid again. Copying was better than drawing, and there was positive transfer to a subsequent drawing. Tracing was very accurate, but transfer to drawing did not occur, possibly because of the automatic nature of tracing. In Experiment 2 (n = 120) different groups received versions of the copying task that differed in the extent to which temporal order of line copying was structured. Asking children to copy the lines in a systematic order led to improved copies, but this performance did not carry over to a subsequent drawing of the solid. In contrast, when temporal ordering of line copying was not manipulated, there was positive transfer from copying to the subsequent drawing. In Experiment 3 (n = 80), provision of structure that emphasized faces by color-groupings of lines or coloring faces led to improved copies and did not hinder transfer to drawing the solid. Experiment 4 (n = 90) showed that in a solid drawing task emphasis on faces but not edges produced a positive effect, both on the immediate drawing and on a subsequent drawing of a plain cube. We conclude that emphasis on order of line copying improves performance in a copying task because in that case line-to-line matching is an important element of the skill, whereas this does not aid drawing of the solid object, in which the focus is primarily on representation of faces and their interrelations.

Child↗
PubMedDate not supplied

Inside madness.

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

Peritoneal leakage of gastric contents, a rare complication of percutaneous endoscopic gastrostomy.

BACKGROUND: A 94-year-old man underwent a routine percutaneous endoscopic gastrostomy but 7 days later developed abdominal pain and died of a previously unreported late complication. METHODS: A case report of the main clinical and pathological findings and a brief discussion of the significance of the case. RESULTS: Postmortem examination revealed a chemical peritonitis due to leakage of 2.8 L of formula into the peritoneal cavity through an enlarged gastrostomy hole around a correctly positioned tube. CONCLUSION: This is a previously unreported complication that occurred because of repeated pulling on the tube by a confused patient, causing a loss of the usual apposition of the gastric and the anterior abdominal walls. The importance of the case is to emphasize that late, even fatal, complications can occur until a permanent fibrous tract has been formed between the skin and the gastric wall.

Aged↗
PubMedDate not supplied

Relocation appraisal, functional independence, morale, and health of nursing home residents.

Relocation to a nursing home can be stressful and may result in mental and physical illness. Appraisal, or the meaning assigned to relocation, can influence relocation outcome. This study examined the relationships between appraisal of relocation and 30 nursing home residents' psychological and physical health, morale, functional independence, and demographic and situational factors, including age, gender, income, education, prior residence, participation in the decision to relocate, and preparation for the move. Positive, benign, and challenge appraisals were related to higher morale and functional independence. Threat appraisal was related to poorer psychological health and lower morale. Harm-loss appraisal was associated with lower morale and lower functional independence. Preparation for the move was related to higher positive appraisal, higher morale, functional independence, and lower harm-loss scores. Implications include the need to assess people's appraisal of relocation so as to plan strategies that prevent relocation stress.

Activities of Daily Living↗
PubMedDate not supplied

Pro-opiomelanocortin-derived peptides in transected and contralateral motor nerves of the rat.

An immunocytochemical method was used to reveal beta-endorphin and alpha-melanotropin peptides in nerve profiles at the neuromuscular junctions in the soleus and extensor digitorum longus muscles of the adult rat. After unilateral section of the sciatic nerve, the proportion of endplates with immunoreactive nerve profiles increased in the denervated muscles even after the axonal material in the distal nerve segments had degenerated. When the nerve was sectioned in the mid-thigh region the proportion of immunoreactive endplates increased with time up to 24-36 h after the nerve section and then eventually declined. The incidence of immunoreactive nerve profiles also increased in the proximal stump. After unilateral sciatic nerve section there was also an increase in the incidence of immunoreactive endplates in the contralateral muscles. The increases in the contralateral muscles could be detected at an earlier time if the nerve was sectioned closer to the spinal cord. The possibility is discussed that the expression of pro-opiomelanocortin peptides in the motor nerves is tonically suppressed in the normal adult but the inhibition is released after section of the nerve. The findings indicate that a signal is transferred from the site of injury in the transected nerves to the motor nerves of the contralateral limb via a transneuronal mechanism through the spinal cord.

Adrenocorticotropic Hormone↗