Liquid chromatographic determination of thiamine in rodent feed by postcolumn derivatization and fluorescence detection.

A liquid chromatographic method was developed for determination of the essential nutrient thiamine (vitamin B1) in rodent feed. Thiamine was extracted with hydrochloric acid, separated by reversed-phase liquid chromatography, derivatized postcolumn to thiochrome with potassium hydroxide and potassium ferricyanide, and detected by fluorescence. Excitation and emission wavelengths were 370 and 430 nm, respectively. Detector response was linear in the range of 2.58 to 15.5 ng of thiamine injected. Instrument detection limit was 5 pg of thiamine injected.

Reasons for increasing administrative costs in hospitals.

OBJECTIVE: To evaluate trends in administrative expenditures by examining changes in administrative costs compared with other areas of the hospital budget, changes in expenditures for patient care departments compared with nonpatient care departments, and departments with a greater number of regulatory requirements compared with those with fewer regulatory requirements. DESIGN: Annual hospital operating budgets submitted to Blue Cross were examined for an 8-year period from 1983 to 1990. PARTICIPANTS: Seventy hospitals in Western Pennsylvania. MEASUREMENTS: Annual operating expenditures. RESULTS: Total administrative expenditures showed a larger growth rate (90%) than service departments (29%), ancillary services (30%), professional care (52%), miscellaneous expenses (70%), and the total hospital budget (45%). Administrative costs increased from 10.6% as a proportion of the total hospital budget in 1983 to 13.9% in 1990. These increases were seen regardless of hospital size. Departments with a greater number of regulatory obligations had a greater increase in expenditures (84%) than did departments with fewer regulatory requirements (5%). However, overall expenditures in departments with direct patient care responsibilities did not increase appreciably faster (44%) than in departments not providing clinical services (46%), possibly reflecting the fact that administrative costs may be increasing equally in both areas. CONCLUSIONS: Administrative costs were found to be one of the fastest growing components of hospital budgets. Future research should determine the effect of these increases on the quality of patient care.

Characterization of seven antihistamines, their N-oxides and related metabolites by fast atom bombardment mass spectrometry and fast atom bombardment tandem mass spectrometry.

We have examined the synthetic N-oxides of five ethylenediamine-type antihistamines using fast atom bombardment (FAB) mass spectrometry and FAB tandem mass spectrometry (MS/MS). Fragmentation of the protonated molecule in the normal and collisionally activated spectra appeared to be characteristic for this class of antihistamine N-oxide. Spectra were also acquired from an ethanolamine and a propylamine antihistamine N-oxide for comparison. These results were very similar to those obtained from biologically produced antihistamine N-oxides, as well as isomeric metabolites, which were readily distinguished from the N-oxides by characteristic fragmentation. In addition, a prominent ion 16 daltons lower in mass, which has been attributed to loss of elemental oxygen from the protonated N-oxide in chemical ionization mass spectral studies, was shown to be a matrix-dependent product of the solution-phase reduction of the antihistamine N-oxide to the parent antihistamine during FAB ionization. These results demonstrate that with a non-reducing matrix such as glycerol, FAB mass spectrometry and FAB MS/MS are excellent methods for the characterization of the non-conjugated antihistamine metabolites such as the N-oxides.

Cholesterol emboli after cardiac catheterization. Eight cases and a review of the literature.

Cholesterol embolization is a puzzling event that may be increasingly iatrogenic in origin. Diagnosis is difficult and requires a high index of suspicion, an appropriate clinical picture, and usually, confirmation by biopsy. Certain laboratory abnormalities may be helpful; the elevated sedimentation rate and relative eosinophilia found in our patients concurs with other cases reported in the literature. Prognosis is related to the extent of systemic involvement, but renal disease is particularly threatening and gangrene and infection can be lethal. Multiple therapeutic regimens have been generally unsuccessful in altering the course of the disease process. The most significant impact on the disease can be made by its prevention. Cholesterol emboli occur spontaneously, but also after invasive aortic procedures such as diagnostic angiography or cardiovascular surgery. In addition, cardiac catheterization and percutaneous transluminal coronary angioplasty have the potential for arterial trauma and consequent cholesterol embolization. Although the apparent increasing numbers of cholesterol emboli may be a reflection of the increased use of arterial invasive procedures, they are being performed on an older, more severely ill population, with other risk factors for the development of embolic phenomena, i.e., age, smoking history, diabetes mellitus, hypertension, and peripheral vascular disease. Our observed cases and review of the literature do not furnish information concerning the comparative incidences of embolization as related to the suggested etiologies. Careful documentation of the clinical situation preceding the event, the type of procedure, the site of arterial entry, and the duration, difficulty, and extent of the intravascular invasion (i.e., above or below the left subclavian artery) are necessary for this purpose. Such data should help to develop guidelines for patient and procedure selection in order to minimize the possibility of cholesterol embolization.

Severe proliferative retinopathy as the only sign of sickle cell hemoglobin C disease.

A 48-year-old black woman developed severe bilateral hypoxic proliferative retinopathy without other clinical manifestations. The hemoglobin level was 10.6 to 11.5 g/100 ml, reticulocyte level was 2.2%, targeted and sickled red blood cells were seen on blood smears, and hemoglobins S and C were demonstrated by electrophoresis. Glucose tolerance test was normal. The development of neovascular proliferation, vitreous hemorrhage, and retinal detachment unassociated with other clinical symptoms is unusual in sickle cell hemoglobin C disease.