Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Paediatric dacryocystorhinostomy

Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.     

Protein kinase-A and the effects of parathyroid hormone on phosphate uptake in opossum kidney cells

Current evidence indicates that signal transduction after receptor binding of PTH involves the stimulation of adenylate cyclase as well as stimulation of phosphoinositide metabolism. Recent studies, showing that PTH alters phosphate transport in opossum kidney cells at concentrations which do not increase cAMP production and that activators of protein kinase-C also alter phosphate transport, have led to the suggestion that there is a dual mechanism for the regulation of phosphate transport by PTH, namely, protein kinase-C at physiological levels of PTH and cAMP at higher levels of PTH. The present studies were designed to evaluate the relationship between cAMP-dependent protein kinase (PK-A), a more sensitive indicator of alterations in cAMP metabolism than measurements of total cellular cAMP, and phosphate transport in opossum kidney cells, in response to bovine (b)PTH 1-34 and [Nle8,Nle18,Tyr34]bPTH 3-34 amide. While bPTH 1-34 markedly stimulated cAMP accumulation (half-maximal stimulation between 1 and 10 nM), PTH 3-34 analog did not. Phosphate transport was inhibited in a dose-dependent manner by bPTH 1-34, with half-maximal effect occurring between 0.1 and 1 nM. [Nle8,Nle18,Tyr34]bPTH 3-34 amide also altered phosphate transport, although this peptide was 3 orders of magnitude less potent than bPTH 1-34. PK-A activity increased in response to bPTH 1-34 and correlated closely with the effects of PTH on phosphate transport. [Nle8,Nle18,Tyr34]bPTH 3-34 amide, which did not appear to increase cAMP, also resulted in a significant increase in the activity of PK-A. Studies of inhibition of cAMP accumulation using 2',5'-dideoxyadenosine demonstrated that while this agent markedly inhibited the accumulation of cAMP in response to PTH, the effects of PTH on phosphate transport were not altered. However, in spite of the reduction in cAMP the activation of PK-A was similar to control. These data indicate that the effects of PTH peptides on phosphate transport are more closely related to changes in the activity of PK-A than to levels of total cAMP. Activation of PK-A in response to PTH is demonstrable at the lowest doses of PTH that alter phosphate transport.     

Attitudes of rural and urban elderly concerning supplement use

To examine supplement purchase practices and attitudes toward supplements of rural and urban elderly, two questionnaires were designed. One questionnaire included demographic questions, an attitude scale, and questions concerning supplements purchases and sources of information about nutrition. The second questionnaire contained an advertisement about calcium supplements followed by questions regarding means to "improve calcium" and health concerns. The rural elderly had a significantly lower mean education level and a significantly higher number of misconceptions. The average expenditures on supplements were $52.00 per month for the total group and sources of information were media, physicians, family and friends. In response to the advertisement, nearly one-third of the respondents reported that they would be unlikely to take calcium supplements to improve calcium even though 86.7% stated they would take calcium supplements to prevent health problems and 51.7% believed there could be dangers in taking calcium supplements. The most commonly reported means to improve calcium were to increase milk and to eat cheese (86.7% each). Contradictions in the responses may indicate that these elderly are susceptible to advertising implying supplements are needed to prevent health problems.