Diagnosis of Cryptococcosis: Comparison of Various Methods to Detect Cryptococcus Neoformans

Summary: The diagnosis of cryptococcal meningitis may be difficult to establish when few organisms are present in the cerebrospinal fluid. For this reason, we determined which of several different visual and cultural methods were the most sensitive for the detection of Cryptococcus neoformans. Gram stain and India ink preparations required that 10⁵ organisms per ml be present before these methods were reliably positive; centrifugation increased the sensitivity of these assays 10-fold. Culturing a loopful of the sample required that 10³ organisms per ml be present to yield growth; centrifugation of the sample enhanced the sensitivity of the culture by 100-fold. Clearly the most sensitive assays, both detecting fewer than 1 organism per ml, were culture of a membrane filter through which the entire sample had been passed and culture of the entire sample in a flask using biphasic medium. Zusammenfassung: Die Diagnose der Crytococcus-meningitis kann Schwierigkeiten bereiten, wenn nur wenige Erreger im Liquor cerebrospinalis vorhanden sind. Aus diesem Grunde wurden Untersuchungen durchgeführt urn festzustellen, welche optische oder kulturelle Methode die höchste Nachweisempfindlichkeit für Cryptococcus neoformas besitzt. Die Gramfärbung und die Aufschwemmung in chinesischer Tube benötigen 10⁵ Zellen/ml um verläßlich positive Befunde zu ergeben. Durch Zentrifugierung des Liquors konnte die Empfindlichkeit auf das 10-fache gesteigert werden. Bei der Abimpfung einer vollen Impföse war es erforderlich, daß das Untersuchungsmaterial mindestens 10³ Organismen/ml enthielt, damit in der Kultur Wachstum entstand. Mit der Zentrifugierung des Materials wurde die Empfindlichkeit bei dieser Methode auf das 100-fache erhöht. Als empfindlichste Nachweismethoden erwiesen sich die Membranfiltermethode, bei der die gesamte Probe filtriert und anschließend kultiviert wird, sowie die Kultivierung der gesamten Probe in einer Kulturflasche mit biphasischem Nährmedium. Mit beiden Methoden lassen sich weniger als ein Organismus/ml entdecken.     

Cytocidal Activity of a Synthetic Isoprenoid, N-Solanesyl-N, N'-bis(3,4-dimethoxy-benzyl)ethylenediamine, and Its Potentiation of Antitumor Drugs against Multidrug-resistant and Sensitive Cells in vitro

A synthetic isoprenoid, N-solanesyl-N, N'-bis(3,4-dimethoxybenzyl)ethylenediamine (SDB-ethylene-diamine), inhibited the colony formation of multidrug-resistant mutant cell lines derived from Chinese hamster V79 (V79/ADM) and human hepatoma PLC/PRF/5 (PLC/COL) cells to a greater extent than that of the parental cells. When combined with other clinically useful antitumor agents, it potentiated the cytotoxic activity of almost all kinds of drugs tested including adriamycin (ADM), actinomycin D, vincristine, cytosine arabinoside, and 5-fluorouracil (5-FU), and the potentiation ratios were higher against V79/ADM cells than against V79/S cells. Among the antitumor agents tested, the activities of bleomycin-group antibiotics were more strongly enhanced by SDB-ethylenediamine and the potentiation was higher in the parental cells than in V79/ADM cells. SDB-ethylenediamine enhanced the uptake of ADM and daunorubicin into V79/ADM and its parental cells, but it did not increase the uptake of 5-FU or peplomycin, indicating that different mechanisms operate for potentiation in the cases of the latter drugs, i.e., not simply an increase of intracellular drug uptake. Two fragments of SDB-ethylenediamine, solanesol (polyprenoid moiety) and the diamine component (verapamil-like moiety), showed neither cytotoxic activity nor potentiator activity, even if they were mixed together, indicating that the steric conformation of intact SDB-ethylenediamine molecule is important for these two activities.     

Block-independent control of distributed structures

As a compromise between coupled control and independent modal-space control, a block-independent control method is proposed. The computational difficulties encountered in coupled control are thereby reduced significantly. The requirement on the number of actuators is shown to be lower for block-independent control than for independent modal-space control, but only moderately so. A numerical example is presented.     

Identification of a neuronal endocytic pathway activated by an apolipoprotein E (apoE) receptor binding peptide

Apolipoprotein E (apoE) is the only serum apolipoprotein that is also found in the extravascular fluid of the brain, where it is thought to play an important role in lipid transport in the central nervous system. In addition apoE has also been implicated in neural regenerative processes and in the etiology of Alzheimer's disease. Peptides derived from the receptor binding domain of apoE are biologically active and bind to low density lipoprotein (LDL) receptors and LDL receptor related protein. There is, however, no direct evidence that these apoE peptides are able to directly activate the endocytic process, either in the brain or elsewhere. In the present paper, we have used electron microscopy and video imaging fluorescence microscopy to investigate the effects of a peptide derived from the receptor binding domain of human apoE on endocytosis in cultured rat cortical neurons. We have found that this tandem dimer repeat peptide induces neuronal endocytosis via a receptor associated protein sensitive pathway. Although the peptide induces a rise in cytoplasmic calcium, this is not required for the induction of endocytosis. On the other hand, normal processing of the endocytic vesicles does appear to require the elevation of cytoplasmic calcium, since inhibition of the calcium response results in the accumulation of large endocytic vesicles.     

Frequency and distribution of salpingitis and pelvic inflammatory disease in short-stay hospitals in the United States

Pelvic inflammatory disease is not a reportable condition in the United States. Based on data extracted from the Hospital Discharge Survey conducted by the National Center for Health Statistics, this article presents estimates of the frequency and distribution of PID in short-stay hospitals from 1970 through 1975.     

The tracer method of curriculum analysis: identifying changes in oncology subject matter in medicine

Changes occurring in oncology subject matter in an undergraduate medical curriculum over a 5-year period were documented using the tracer method of curriculum analysis. The tracer method is an empirical approach somewhat analogous to tracing one thread through a tapestry, as a way of following a subject matter interwoven throughout a curriculum. Advantages of the method can be to bring particular material to the attention of teaching staff and students, to facilitate more efficient instruction, and to introduce peer review of educational material.     

Gonococcal pelvic inflammatory disease: Case-finding observations

During a 20 month period, 110 women with gonococcal pelvic inflammatory disease and 165 women with uncomplicated gonorrhea were provided intensive case-finding services (interviewing of patients and tracing of contacts). Approximately three contacts per case were investigated, and 24.3% of the 859 male contacts were infected. Nearly two thirds (64.6%) of the infected contacts were asymptomatic. Active public health intervention was frequently necessary to persuade asymptomatic men to seek medical attention; removal of these men from the disease pool may serve to prevent reinfection of treated women and to diminish the transmission of gonorrhea.     

The Choice of Feedback Stimulus Can Determine the Success of Alpha Feedback Training

The experimenter's choice of auditory feedback stimulus may determine the success of alpha feedback training, The stimulus medium of the feedback message may interfere with or enhance the person's ability to increase alpha activity. Forty undergraduates were randomly assigned to one of two feedback stimulus groups or one of two stimulus control groups. The two auditory stimuli used for feedback produced dramatically different effects on the spectral power in high and low frequency alpha during training, whereas the stimulus controls showed little change from eyes open baselines. The experiences associated with the auditory stimuli before training and the alpha levels for the pre and post stimulus baselines were significant predictors of alpha changes during training. These results suggest that the feedback stimulus may influence how alpha information is received and utilized by affecting arousal, attentional capacity, and control strategies, or may directly influence the generators of the alpha rhythm.