Biomedical subjects
Publications and source records attributed to T Clark.
Six patients with persistent phenothiazine dyskinesia were treated in a double-blind controlled trial with tetrabenazine 100 mg in divided dosage. In three patients the abnormal movements were abolished and in two others there was some improvement, but this was no greater than that achieved with the diazepam control. Tetrabenazine may be useful in the treatment of some patients with persistent phenothiazine dyskinesia.
We present QSPR models for normal boiling points employing a neural network approach and descriptors calculated using semiempirical MO theory (AM1 and PM3). These models are based on a data set of 6000 compounds with widely varying functionality and should therefore be applicable to a diverse range of systems. We include cross-validation by simultaneously training 10 different networks, each with different training and test sets. The predicted boiling point is given by the mean of the 10 results, and the individual error of each compound is related to the standard deviation of these predictions. For our best model we find that the standard deviation of the training error is 16.5 K for 6000 compounds and the correlation coefficient (R2) between our prediction and experiment is 0.96. We also examine the effect of different conformations and tautomerism on our calculated results. Large deviations between our predictions and experiment can generally be explained by experimental errors or problems with the semiempirical methods.
We present a temperature-dependent model for vapor pressure based on a feed-forward neural net and descriptors calculated using AM1 semiempirical MO-theory. This model is based on a set of 7681 measurements at various temperatures performed on 2349 molecules. We employ a 10-fold cross-validation scheme that allows us to estimate errors for individual predictions. For the training set we find a standard deviation of the error s = 0.322 and a correlation coefficient (R(2)) of 0.976. The corresponding values for the validation set are s = 0.326 and R(2) = 0.976. We thoroughly investigate the temperature-dependence of our predictions to ensure that our model behaves in a physically reasonable manner. As a further test of temperature-dependence, we also examine the accuracy of our vapor pressure model in predicting the related physical properties, the boiling point, and the enthalpy of vaporization.
Magnetic resonance (MR) imaging is an accurate means of analyzing disruptions of the native anterior cruciate ligament (ACL). Various techniques may be used to repair a disrupted ACL. A common repair is the MacIntosh lateral-substitution over-the-top repair in which a strip of fascia lata from the iliotibial band is used as a "neoligament." The results of 27 MR examinations of 17 athletes with this repair were analyzed to determine the appearance of the neoligament on MR. Thirteen of the 17 patients had returned to full athletic activity and four were capable of strenuous activity. Examinations were made at both 0.5 and 1.5 T in varied extents of external rotation from 0 to 20 degrees, and at variable time intervals after surgery from 1 to nearly 40 months. Only two patients clinically required postrepair arthroscopy, but both had normal repairs. Neoligaments were classified as well-defined (n = 6 studies), ill-defined (n = 10), and not discernible (n = 11), based on clarity of appearance. Reasons for this variable appearance include the variable presence of fibrous and fatty tissue investing the neoligament. We conclude that the normal neoligament, unlike the normal active ACL, has a variable appearance, including nonvisualization on MR and that criteria used in evaluating the native ligament will be inadequate to assess the repair.
Neuroleptic Malignant Syndrome, a serious and sometimes fatal complication, has been reported to occur in some patients with the administration of neuroleptic medications. Clinically it is manifested by four groups of symptoms which include muscular hypertonicity, autonomic instability, altered consciousness, and hyperthermia. Laboratory findings such as elevated creatinine phosphokinase and leukocytosis are also seen. While it is true that the incidence of the full blown clinical picture of this syndrome is rare, the authors report that only muscular hypertonicity and autonomic instability have occurred frequently in their setting leading to discontinuation of neuroleptics. Such abortive cases may go undetected. If properly diagnosed, the occurrence of this syndrome is not as rare as the published reports indicate. Second, it is reported that rechallenge with neuroleptics may not induce Neuroleptic Malignant Syndrome again. The authors noted recurrence of fever after rechallenge with a different neuroleptic drug. This article describes the method of early recognition and prevention of morbidity as well as mortality.
The present Guidelines were prepared by the Guidelines Sub-Committee of the World Health Organization-International Society of Hypertension (WHO-ISH) Mild Hypertension Liaison Committee, the members of which are listed at the end of the text. These guidelines represent the fourth revision of the WHO-ISH Guidelines and were finalised after presentation and discussion at the 7th WHO-ISH Meeting on Hypertension, Fukuoka, Japan, 29th Sept-1st Oct, 1998. Previous versions of the Guidelines were published in Bull WHO 1993, 71:503-517 and J Hypertens 1993, 11:905-918.
Classification and nomenclature schemes are guidelines and are not intended to recognize and distinguish the entire spectrum of any single disease. It may in fact be misleading to suggest that a classic presentation of a given disease plus atypical features should be considered an "overlap" of two separate, often rare, conditions. We report a case of typical Wegener's granulomatosis (WG), with the coexistence of pulmonary artery stenosis, a lesion more commonly observed in TA. This is not the first or only example of large vessel vasculitis occurring in patients with WG. This observation cautions clinicians to avoid rigid application of classification and nomenclature systems and raises questions about determinants of vasculitis subsets and organ targeting.
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