Graded comprehensive cardiopulmonary exercise testing in the evaluation of dyspnea unexplained by routine evaluation

The evaluation of dyspnea is problematic when a cause is inapparent after initial diagnostic studies. We examined the results and role of cardiopulmonary exercise testing (CPET) in 50 patients with a mean 23 months of dyspnea and normal FEV1 and FVC. The CPET studies were interpreted by a panel and a consensus reached. Subsequent tests ordered by the primary physician were reviewed, and a final diagnosis was agreed on by the panel. Seven of 50 patients had cardiac limitation, 17 of 50 had pulmonary limitation, 14 of 50 had obesity and/or deconditioning, 1 of 50 had gastroesophageal reflux, and 16 of 50 had either psychogenic dyspnea or no identifiable disease. Five patients had more than one clinical diagnosis accounting for 55 diagnoses in the 50 patients. Those with a normal CPET had a higher VO2max and O2 pulse than those with cardiac disease, deconditioning, or hyperactive airways disease (HAD) (p < 0.05). Electrocardiographic changes identified cardiac disease while studies demonstrating ventilatory limitation identified a pulmonary process. In 24, deconditioning could not be distinguished from cardiac limitation. Of these, 14 responded to exercise training and/or weight loss, whereas 3 had cardiac disease, 7 had HAD, and 4 had psychogenic dyspnea (4 had more than one clinical diagnosis). In the 13 patients with normal CPET results, one had gastroesophageal reflux, two had HAD, four had psychogenic dyspnea, and six had no identifiable disease. We conclude that a diagnosis can be made in most patients with chronic dyspnea; however, further studies including bronchoprovocation are often required. Cardiopulmonary exercise testing is useful in identifying a cardiac or pulmonary process, but it is insensitive in distinguishing cardiac disease from deconditioning.     

Occupational stress and dentistry: theory and practice. Part II. Assessment and control

Since dentistry has been identified as being a stressful profession, dentists, with the help of the members of the dental team, must attempt to achieve a relatively stress-free working environment. In addition to recognising potential occupational stressors it is important for dentists to be able to assess their emotional responses to the practice of dentistry and to arrange their daily working lives in such a way as to reduce occupational stress. This paper examines the means by which dentists may assess occupational stress as well as person-centred and/or situation-centred strategies of coping with and controlling occupational stress in general dental practice.     

Trends in glove use by dentists in England and Wales: 1989-1992

The routine wearing of gloves during the dental treatment of patients forms an integral part of the recommended guidelines of many authorities worldwide. Compliance has been variable but there is evidence to show that this is increasing, as are other cross-infection control measures. A survey of glove use by general dental practitioners in England and Wales was carried out in 1989. This paper reports a follow up study in 1991/2 which aimed to identify any differences that had occurred in the interim. The results indicated that there was increasing compliance with recommended cross-infection control measures, although only one fifth of respondents were found to change gloves between patients. Of those practitioners who did not change gloves between patients, half considered that blood contact was not a reason for changing gloves. Comparisons are made with compliance rates in other countries and recommendations made for further education within the dental profession on the subject of cross-infection control.     

Mumps orchitis; review of 8 cases]

The occurrence of secondary hypogonadism is a common finding in males who seek help with erectile dysfunction, although the relationship to diminished testosterone is unclear. Two possibilities exist regarding both the genesis and maintenance of the hypogonadotropic hypogonadal state. First, a defect in hypothalamic function, resulting in downregulation as well as in alterations of anterior pituitary function; second, estradiol inhibition of gonadotropin release, both of which result in decreased testosterone production. As testosterone levels decrease and estradiol levels increase, the ratio of free testosterone to estradiol reaches a critical point and the estrogenic gonadotropin suppressive effects predominate. This ratio may signal the biological point of no return and could become one of the criteria for defining the separation of the transitional hypogonadal state from the final 'end stage' hypogonadotropic hypogonadal state. As the aging process continues, there is a relative accumulation of fatty tissue, and aromatization accelerates the conversion of testosterone to estradiol. This additional secondary estradiol inhibition results in the maintenance of the testosterone deficient state, and the aging process continues uncontested.     

Increasing breast and cervical cancer screening in low-income women

Active cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS) was treated with an intraocular sustained-release ganciclovir implant. A total number of 19 implants were performed in 15 eyes of 9 AIDS patients. The intraocular sustained-release ganciclovir was effective in preventing reactivation of CMV retinitis in 15 of the 19 implants, ineffective in 3, and undetermined in 1. All ineffective cases had been resistant to ganciclovir therapy before the implants. Vision after the therapy was maintained at better than 0.5 except for one eye. There were no serious ocular complications caused by the therapy. Among 5 patients with unilateral CMV retinitis, 2 unaffected eyes developed CMV retinitis during this therapy. In addition, another patient developed presumed CMV infection in other systemic organs. Based on these data, the intraocular sustained-release ganciclovir implant was considered to be useful for the treatment of CMV retinitis in AIDS.     

Regional and cellular expression of glial (GLT1) and neuronal (EAAC1) glutamate transporter proteins in ovine fetal brain

Glutamate transport is a primary mechanism for regulating extracellular levels of glutamate which can have either neurotrophic or neurotoxic effects in the developing brain, depending on its concentration. Using immunoblotting and immunocytochemistry, we tested the hypotheses that expression of neuronal and glial glutamate transporter proteins was regionally and temporally regulated in the developing ovine brain and that expression of the glial isoform early in development was not cell-type specific. Immunoblots for the neuronal glutamate transporter EAAC1 revealed a major band of immunoreactivity at 69,000 nmol. wt, whereas glial glutamate transporter-1 (GLT1) immunoreactivity was observed as 73,000 and 146,000 mol. wt proteins. EAAC1 and GLT1 are regulated differently during development, with EAAC1 immunoreactivity being most abundant at 60 and 71 days completed gestation (term=145 days) and dissipating thereafter, while GLT1 immunoreactivity was most abundant at 136 days gestation. By immunocytochemistry EAAC1 expression is neuronal throughout gestation with intense labelling of dendrites within the telencephalon evident at 60 days. Neuropil, neuronal cell bodies and processes are EAAC1-immunoreactive throughout gestation with no evidence of astrocytic or oligodendroglial immunoreactivity. In contrast, GLT1 is expressed by neuronal and non-neuronal cell types during midgestation with astrocyte selectivity developing by 136 days. During midgestation, GLT1 is transiently expressed in neurons of the subplate, cranial nerve nuclei, basal ganglia, and cerebellar cortex. The major finding of this study, that GLT1 is transiently expressed in various neuronal populations at midgestation demonstrates that the cell-type specificity of the GLT1 phenotype is developmentally regulated and depends on brain maturity.     

The shapes of the motor domains of two oppositely directed microtubule motors, ncd and kinesin: a neutron scattering study

The shapes of the motor domains of kinesin and ncd, which move in opposite directions along microtubules, have been investigated. Using proteins expressed in Escherichia coli, it was found that at high salt (> 200 mM) Drosophila ncd motor domain (R335-K700) and human kinesin motor domain (M1-E349) were both sufficiently monomeric to allow an accurate determination of their radii of gyration (Rg) and their molecular weights. The measured Rg values of the ncd and kinesin motor domains in D2O were 2.06 +/- 0.06 and 2.05 +/- 0.04 nm, respectively, and the molecular weights were consistent with those computed from the amino acid compositions. Fitting of the scattering curves to approximately 3.5 nm resolution showed that the ncd and kinesin motor domains can be described adequately by triaxial ellipsoids having half-axes of 1.42 +/- 0.38, 2.24 +/- 0.44, and 3.65 +/- 0.22 nm, and half-axes of 1.52 +/- 0.23, 2.00 +/- 0.25, and 3.73 +/- 0.10 nm, respectively. Both motor domains are described adequately as somewhat flattened prolate ellipsoids with a maximum dimension of approximately 7.5 nm. Thus, it appears that the overall shapes of these motor domains are not the major determinants of the directionality of their movement along microtubules.