Clinical and radiological diagnosis of Crohn's disease in children

Diagnosis of Crohn's disease in children may be delayed because of obscure presentation and inappropriate investigation. The clinical and radiological features in 35 children with Crohn's disease were reviewed retrospectively. The distal ileum and proximal colon were the most common sites of disease. Intestinal symptoms and signs were often overshadowed by nonspecific complaints. Proximal small bowel disease was characterised by oedema, clubbing, anaemia, and stunting of growth. The delay in diagnosis was less than in other series, although most prolonged in the group with proximal disease. We have identified a group of clinical features that strongly suggests Crohn's disease. In these patients, we believe a small bowel enema is justified. Small bowel enema, although invasive, is more effective than barium meal and follow-through for demonstrating Crohn's disease. Severity of radiological changes did not correlate with clinical assessment. Neither bowel stricture nor fistula was found. Radiology of the colon was insensitive and colonoscopy is better for assessing colonic disease.     

Enhancement of ketoconazole penetration across the blood-brain barrier of mice by dimethyl sulfoxide.

Mice were treated with ketoconazole with and without dimethyl sulfoxide. Concentrations of ketoconazole at 3 and 5 h after treatment were significantly higher in serum (P less than 0.05) and brain tissue homogenate (P less than 0.01) of mice treated with dimethyl sulfoxide than in those of mice not treated with dimethyl sulfoxide.     

Prednisone-induced worsening of neuromuscular function in myasthenia gravis

In patients with myasthenia gravis who received single doses of prednisone orally (40 to 100 mg), we found acute inhibition of neuromuscular function as manifest by increased decremental responses to repetitive nerve stimulation, reduced twitch tension, and lowered maximum voluntary contraction strength. The time course of these changes correlated with plasma methylprednisolone levels, implying direct drug effects on neuromuscular function.     

Rapid digital filtering

Image filtering with the larger, and potentially most valuable, digital filters is very time-consuming, thus precluding use of these filters in routine clinical applications. A recently developed algorithm for spatial-domain filtering is described, and its speed is compared with those of conventional methods with and without an array processor. Using the new Chebyshev method, a 64 by 64 pixel image can be filtered on a standard 16-bit minicomputer with filters of size 3 by 3 to 23 by 23 in 1.4-9.2 sec. The conventional spatial-domain algorithm requires 3.8-71 sec. With an array processor, filtering is accomplished in 0.19-0.54 sec. Filtering in the frequency domain requires 34 sec without an array processor and 0.12 sec with one. Thus with this new Chebyshev algorithm, clinically practical digital filtering can be performed with large filters even without an array processor.     

Evidence for the ventral origin of oligodendrocyte precursors in the rat spinal cord

The neuroepithelial cells of the mammalian neural tube are thought to give rise to all classes of differentiated neurons and macroglial cells in the adult CNS. In most cases, the regulation and timing of commitment of neuroepithelial cells to specific differentiative pathways are unknown. It has been proposed that in developing spinal cord, the macroglial cells--astrocytes and oligodendrocytes--arise either by the direct transformation of radial glial cells in the developing cord or, alternatively, by the differentiation of distinct precursor cells which migrate to presumptive white matter from the region of the central canal during development. In this study, the timing of oligodendrocyte differentiation in different levels of the spinal cord and the capacity of specific regions of the spinal cord to give rise to oligodendrocytes at various ages was tested in vitro. At embryonic day 14, all complete segments, as well as all ventral regions along the rostral-caudal axis of the spinal cord, have the capacity for oligodendrogenesis. By contrast, dorsal regions of the thoracic and lumbar spinal cord do not develop the capacity for oligodendrogenesis until later in development. The capacity of dorsal rat spinal cord to give rise to oligodendrocytes appears to be associated with the ventral-to-dorsal migration of oligodendrocyte precursors. These observations suggest that commitment to an oligodendrocyte differentiative pathway appears to occur in a distinct population of ventrally located glial precursors in the embryonic rat spinal cord.     

Estimating shelf-life of drugs in solution

The use of pseudo-first-order chemical reaction kinetics and Arrhenius thermodynamic principles in estimating the effect of temperature on shelf-life of drug solutions is described. The degradation of many drugs in aqueous solutions occurs by hydrolysis. Equations using activation energy of the hydrolysis reaction (Ea) derived from Arrhenius principles, rate constants, and temperature are used to illustrate the exponential decrease in drug shelf-life proportional to an arithmetic increase in temperature. Use of the Q value, a factor based on Ea, rate constants, and temperature change, is described. The range of Ea for pharmaceutically important degradation reactions is relatively limited; thus, near room temperature, Q values of 2-5 can be used to estimate the effect of temperature change on shelf-lives of drugs in solution. To conservatively estimate effect on shelf-life when Ea is not known, a Q value of 2 is used to predict the increase in shelf-life obtained by decreasing storage temperature, and a Q of 5 is used to predict decrease in shelf-life from increasing the temperature. Sample calculations are used to show the application of equations based on these principles to practical temperature-dependent problems regarding shelf-life. Given information about shelf-life at a certain temperature, pharmacists can estimate safe shelf-life under other temperature conditions by using these equations.     

Tubal sterilization or vasectomy: how do married couples make the choice?

OBJECTIVE: To examine the relative importance of husband, wife, and couple factors as determinants of sterilization method choice. DESIGN: Married couples seeking sterilization interviewed before surgery and again 1 year later. SETTING: Kaiser Permanente Medical Care Program subscribers seeking care at the Kaiser Foundation Hospital, Santa Clara, California. PARTICIPANTS: Two hundred married women seeking a tubal sterilization and their husbands and 200 married men seeking a vasectomy and their wives. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Sterilization method chosen. RESULTS: In a logistic regression model, nine predictor variables correctly classified 94.9% of 395 couples (P less than 0.000). CONCLUSIONS: The choice of a sterilization method is achieved primarily through processes that involve both spouses. The motivations of both husband and wife, their mutual influence and communication, their present pattern of contraceptive use, and what they know about the satisfactions or dissatisfactions of other people who have had sterilizations are all factors that should be taken into account when the clinician helps a patient make the method-choice decision.