Biomedical subjects
Publications and source records attributed to A Jennings.
The discovery of (4-piperazin-1-ylquinolin-6-yl) arylsulfonamides and their binding affinities for a selection of 5-HT and dopamine subreceptors is described. Many compounds show high affinity (pK(i)>8) for the 5-HT(6) receptor and >100-fold selectivity against a range of other receptors. Structure-activity relationships of these compounds are discussed.
Computed tomography and MR imaging are valuable techniques for determining the presence and extent of substernal goiters, their impingement on adjacent structures in the neck and chest, and whether mediastinal masses are thyroidal in origin. This article discusses the advantages and disadvantages of each technique and the radiologic characteristics of substernal goiters. Radiographic examples of both techniques are included to illustrate common clinical settings. Finally, suggestions for choosing which patients will benefit from scanning and which technique will safely provide the maximum information in various clinical settings are discussed.
The effect of changes in runway width on the perception of glide-slope has been the subject of extensive investigations. Despite considerable research, an explanation of this effect has been elusive. A mathematical model for glide-slope perception was published recently based on the premise that a desirable goal of perception is to form a perception with minimal uncertainty. One of the qualitative predictions of that model was that changes in the aspect ratio of the runway would affect the perceived glide-slope. In this article, the predictions of the model are quantified and are shown to be in close agreement with experimental results in the literature.
Attempts to control laboratory workload in the past always proved to be short-lived. We designed a request card based on clinical conditions for a gynaecology out-patient clinic to help clinical staff to adhere to agreed investigation protocols. Each request card had a tick-box associated with a clinical condition. The tests performed for each condition were advertised on a poster in the clinic. The workload was assessed for a 2-year period before and after the introduction of these cards. The numbers of all endocrine tests, except progesterone and sex hormone binding globulin, fell by 19% (P<0.0001) whereas the clinical cases seen remained steady at 227 per month. This report demonstrates that agreed protocols can be implemented but that a persistent aide-mémoire is necessary.
PURPOSE: To demonstrate the safety and effectiveness of intravenous methylprednisolone (IVMP) in the treatment of uveitis in association with multiple sclerosis (MS). METHODS: Uveitis is an unusual manifestation of MS that may be severe, chronic and require systemic immunosuppression therapy. High-dose IVMP has previously been shown to be effective in the treatment of inflammatory eye disease and MS. Eight episodes of uveitis in five patients with MS were treated over a 10-year period in an open, uncontrolled trial. Two patients had chronic anterior uveitis, one patient had bilateral panuveitis and two patients had intermediate uveitis. RESULTS: All patients responded to IVMP with evidence of a decrease in intraocular inflammatory activity and improved visual acuity (VA) within 2 weeks of commencing treatment. There were no severe ocular or systemic steroid side effects. CONCLUSIONS: Intravenous methylprednisolone is an effective, well-tolerated form of therapy for uveitis in patients with MS.
Root development is extremely sensitive to variations in nutrient supply, but the mechanisms are poorly understood. We have investigated the processes by which nitrate (NO3-), depending on its availability and distribution, can have both positive and negative effects on the development and growth of lateral roots. When Arabidopsis roots were exposed to a locally concentrated supply of NO3- there was no increase in lateral root numbers within the NO3--rich zone, but there was a localized 2-fold increase in the mean rate of lateral root elongation, which was attributable to a corresponding increase in the rate of cell production in the lateral root meristem. Localized applications of other N sources did not stimulate lateral root elongation, consistent with previous evidence that the NO3- ion is acting as a signal rather than a nutrient. The axr4 auxin-resistant mutant was insensitive to the stimulatory effect of NO3-, suggesting an overlap between the NO3- and auxin response pathways. High rates of NO3- supply to the roots had a systemic inhibitory effect on lateral root development that acted specifically at the stage when the laterals had just emerged from the primary root, apparently delaying final activation of the lateral root meristem. A nitrate reductase-deficient mutant showed increased sensitivity to this systemic inhibitory effect, suggesting that tissue NO3- levels may play a role in generating the inhibitory signal. We present a model in which root branching is modulated by opposing signals from the plant's internal N status and the external supply of NO3-.
The in vivo binding pattern of the lectin Griffonia simplicifolia II (GSLII) was evaluated in sections of adult cat optic nerve following reports that it is a marker for oligodendrocytes in adult rodent CNS and that it may also be an oligodendroglial lineage marker. Following as closely as possible the immunocytochemical methodology employed in these reports, staining for GSLII was incorporated into sets of consecutive one micron thick sections comprising known cell-type specific reference markers backed up by electron microscopy. With this correlative protocol both lectin positive and lectin negative cells could be reliably identified. The material examined included normal control tissue and tissue containing previously studied demyelinating lesions of various ages in which oligodendrocyte progenitors and precursors have been characterized. GSLII was found to stain not only mature oligodendrocytes in adult cat optic nerve but also activated microglia, macrophages, polymorphonuclear leucocytes and other haematogenous cells. Lectin positivity was not found in oligodendroglial precursors, endothelial cells, astrocytes or ramified microglia. This study emphasises that care needs to be taken before assigning lineage marker status to individual lectins or antibodies.
Knowing who supports elderly African Americans in adhering to their healthcare regimen is vital information. This study found that the majority of elderly individuals discussed their chronic illnesses and problems related to managing their illnesses with family members rather than with formal providers. Additionally, family members were also significant in coordinating transportation; assisting with managing medications, diet, and exercise regimens; and monitoring symptoms of chronic illnesses. These findings provide direction on how to develop effective care plans and affect positive outcomes for elderly African American clients.
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Hypomagnesemia and depletion of the body's magnesium stores is known to be associated with an increased incidence of both cardiac arrhythmias and neurological irritability. In a two-part prospective study we have evaluated whether magnesium deficiency is a significant occurrence in children treated in the intensive care unit after open heart operations, and subsequently have sought to identify how intraoperative metabolic changes were related to the resultant findings. In 41 children studied after operation the plasma magnesium concentration showed a significant decrease from 0.92 mmol/L (10th to 90th centile, 0.71 to 1.15 mmol/L) immediately after operation to 0.77 mmol/L (0.65 to 0.91 mmol/L) on the following morning. The subsequent change in grouped values was not significant but 14 (34.2%) and 7 (17.1%) possessed values of less than 0.7 mmol/L and 0.6 mmol/L, respectively. The occurrence of cardiac arrhythmias was not statistically related to the occurrence of hypomagnesemia. In 21 children perioperative changes in extracellular and tissue magnesium, potassium, and calcium content were measured. It was found that hemodilution with a prime low in magnesium caused a reduction from a median of 0.81 mmol/L to 0.61 mmol/L (p < 0.01). Plasma potassium level, however, was elevated from 3.7 mmol/L to 4.15 mmol/L (p < 0.05) and the ionized calcium content from 1.17 mmol/L (1.07 to 1.25 mmol/L) to 1.49 mmol/L (1.25 to 2.56 mmol/L) (p = 0.0009). The myocardial content of magnesium did not change significantly but skeletal muscle content was depleted from 6.75 mumol/g (2.85 to 8.35 mumol/g) to 5.65 mumol/g (2.45 to 7.2 mumol/g) (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
The author provides a case study of her daughter's sexual abuse as a child and subsequent experiences as a chronically mentally ill client in the mental health system. Information from 17 years of mental health records and anecdotal accounts are used to illustrate the effects of the abuse, her attempts to reach out for help, and the system's failure to respond. There is evidence that a significant subset of psychiatric patients were severely sexually traumatized in childhood. Yet standard interview schedules consistently neglect to ask questions about such abuse, appropriate treatment is seldom available, and clients are often retraumatized by current practices. Psychiatry's historic resistance to addressing abuse as etiology is being challenged today by powerful economic, political, and professional forces leading to the emergence of a new trauma-based paradigm.
We undertook a study to evaluate the patterns of magnesium deficiency that may develop during and following coronary artery bypass operation without cardioplegia. In 18 patients intraoperative measurements of plasma magnesium and potassium concentrations and measurements of cardiac and skeletal muscle content of these ions were taken. The changes in plasma concentrations and excretion were evaluated postoperatively. Hemodilution at initiation of cardiopulmonary bypass caused a 17.3% decrease in plasma magnesium concentration (p < 0.01), which persisted until the first postoperative day. By the fifth postoperative day the level was 19.5% greater than the preoperative value. Urinary excretion of magnesium reflected changes in plasma magnesium concentration. Cardiac muscle content of magnesium decreased by 13.3%. Plasma potassium concentration was elevated by hemodilution (p < 0.01), and muscle potassium was not depleted. We conclude that three patterns of magnesium depletion occur: hemodilution, intraoperative cellular depletion, and postoperative cellular depletion. The findings support the need for magnesium supplementation during and after cardiac operation.
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We present a chromosome classifier for automated karyotyping of banded chromosomes which uses a multi-layer perception neural network. Two network configurations have been investigated. The resulting classifiers have been trained and tested on data from three different data sets covering a range of data quality. Classification results compare very favourably with those obtained using a highly optimised parametric classifier.
Genetic linkage studies were performed in 12 British families with von Hippel-Lindau disease (VHL) using RFLPs at three loci (DNF15S2, THRB, RAF1) on the short arm of chromosome 3. Linkage was detected between the VHL disease locus and RAF1 with a maximum lod score of 3.88 at a recombination fraction of 0.05 (confidence interval 0.003-0.18). Multipoint linkage analysis suggested that the most likely location for the VHL disease locus is telomeric to THRB. These results confirm earlier reports localizing the VHL gene to the short arm of chromosome 3, and provide no evidence for genetic heterogeneity.
Clinical, electrophysiological and ultrastructural morphometric observations were made in 5 diabetic non-neuropathic patients, 5 diabetic patients with mild neuropathy and 11 diabetic patients with severe neuropathy. Capillary abnormalities were assessed in simultaneous nerve, muscle and skin biopsies and compared with results from 6 age-matched, non-diabetic control subjects. Nerve capillaries demonstrated markedly greater pathology than skin and muscle capillaries. Endoneurial capillary density was significantly reduced in severely neuropathic diabetic patients (p less than 0.01) when compared with control subjects. Capillary basement membrane (p less than 0.002), endothelial cell (p less than 0.003) and total diffusion barrier (endothelial cell, pericyte, basement membrane) (p less than 0.001) thickness were significantly increased, and oxygen diffusing capacity was significantly reduced (p less than 0.001) in the nerves of patients with severe diabetic neuropathy when compared to control subjects. Endothelial cell profile number and luminal perimeter were significantly increased in asymptomatic (p less than 0.01), (p less than 0.05) and severely neuropathic (p less than 0.001), (p less than 0.05) diabetic patients respectively. However, endothelial cell outer perimeter, a measure of capillary size, showed no significant increase in diabetic patients when compared with control subjects. An association was observed between neurophysiological and neuropathological measures of neuropathic severity. There was no significant correlation between the duration of diabetes and HbA1 levels with capillary pathology or with neuropathic severity. Very few abnormalities of muscle and skin correlated with neuropathic severity. However, all measures of nerve capillary pathology correlated significantly with neurophysiological and neuropathological measures of neuropathic severity.
We have shown that several commercial control sera containing reversibly inactivated creatine kinase are reactivated by pre-incubation in N-acetyl cysteine assay diluent. The increase in activity can proceed for up to 4 h. This reactivation is not seen in patients' sera even after storage for 14 days at -20 degrees C, 7 days at 4 degrees C, or 2 days at 20 degrees C, during which time no loss of activity was evident. This study brings into question the validity of using consensus values to standardise enzyme assays.