Campafungins: Inhibitors of Candida albicans and Cryptococcus neoformans Hyphal Growth.

Campafungin A is a polyketide that was recognized in the Candida albicans fitness test due to its antiproliferative and antihyphal activity. Its mode of action was hypothesized to involve inhibition of a cAMP-dependent PKA pathway. The originally proposed structure appeared to require a polyketide assembled in a somewhat unusual fashion. However, structural characterization data were never formally published. This background stimulated a reinvestigation in which campafungin A and three closely related minor constituents were purified from fermentations of a strain of the ascomycete fungus Plenodomus enteroleucus. Labeling studies, along with extensive NMR analysis, enabled assignment of a revised structure consistent with conventional polyketide synthetic machinery. The structure elucidation of campafungin A and new analogues encountered in this study, designated here as campafungins B, C, and D, is presented, along with a proposed biosynthetic route. The antimicrobial spectrum was expanded to methicillin-resistant Staphylococcus aureus, Candida tropicalis, Candida glabrata, Cryptococcus neoformans, Aspergillus fumigatus, and Schizosaccharomyces pombe, with MICs ranging as low as 4-8 µg mL-1 in C. neoformans. Mode-of-action studies employing libraries of C. neoformans mutants indicated that multiple pathways were affected, but mutants in PKA/cAMP pathways were unaffected, indicating that the mode of action was distinct from that observed in C. albicans.

How often does computed tomography (CT) of the brain demonstrate a cause for psychosis? A 7-year retrospective study at a tertiary metropolitan hospital.

OBJECTIVES: The aim of the study was to determine the diagnostic yield of computed tomography (CT) of the brain for the investigation of psychosis. METHODS: CT brain requests describing psychosis over a 7-year period at a 500-bed major metropolitan hospital were identified retrospectively. Patients were excluded if they were aged greater than 50 years or if the CT request described focal neurological findings on examination, trauma/falls or known brain tumour, demyelinating disorder, encephalopathy, seizure disorder, congenital brain anomaly, stroke or traumatic brain injury. RESULTS: A total of 805 patients meeting the inclusion and exclusion criteria were identified, representing the largest published study on this topic. Only 0.4% of patients (3 out of 805) had a potential cause for psychosis demonstrated on CT. None of these patients had their management altered as a result. An additional 0.6% of patients (5 out of 805) had significant pathology that was deemed unrelated to their psychosis. CONCLUSIONS: The diagnostic value of CT in the setting of psychosis was found to be extremely low in patients meeting the inclusion and exclusion criteria. Given the risk of ionising radiation and the expenditure of time and cost, more judicious use of CT is suggested.

Imaging of tarsal navicular stress injury with a focus on MRI: A pictorial essay.

Predominantly diagnosed in athletes, stress fracture of the tarsal navicular is becoming increasingly recognised by clinicians as a cause of midfoot pain. Delayed diagnosis can increase the significant morbidity associated with this condition. Consequently the role of MRI is increasing, given the potential to identify a stress reaction in the navicular prior to the development of a discrete stress fracture. It is necessary for radiologists to be familiar with the typical and atypical appearances of this important condition.

Associations Between Antral Ovarian Follicle Dynamics and Hormone Production Throughout the Menstrual Cycle as Women Age.

BACKGROUND: The physiological origins of age-related changes in hormone production during the menstrual cycle are uncertain. OBJECTIVE: The objective of the study was to test the hypothesis that changes in antral follicle dynamics are associated with changes in hormone production as women age. METHODS: A prospective, observational study was conducted in ovulatory women of midreproductive age (MRA; 18-35 y; n = 10) and advanced reproductive age (ARA; 45-55 y; n = 20). The numbers and diameters of all follicles of 2 mm or greater were quantified ultrasonographically every 1-3 days for one interovulatory interval; the growth profiles of individually identified follicles of 4 mm or greater were tabulated. Blood samples were assayed for FSH, LH, estradiol, progesterone, inhibin A and B, and anti-Mullerian hormone. RESULTS: Fifty percent of women in both the MRA and ARA groups developed one to two luteal-phase dominant follicles (LPDFs). MRA women with typical LPDFs had greater luteal-phase inhibin B (44.2 vs 17.0 ng/L) and estradiol (91.3 vs 51.7 ng/L) compared with those without LPDFs (P < .05). Luteal-phase estradiol was greater (184 vs 79 ng/L), inhibin B was greater (25.3 vs 12.7 ng/L), and progesterone was lower (6.98 vs 13.8 µg/L) in ARA women with atypical vs no LPDFs (P < .01). CONCLUSION: Changes in antral follicle dynamics are associated with changes in hormone production as women age. The development of LPDFs in women of MRA was associated with elevated luteal-phase estradiol. A similar but exaggerated elevation in late luteal-early follicular-phase estradiol, accompanied by lower progesterone, was observed in ARA women with atypically large and persistent LPDFs.

Adhesive capsulitis: review of imaging and treatment.

Adhesive capsulitis is one of the most common conditions affecting the shoulder; however, early clinical diagnosis can be challenging. Treatment is most effective when commenced prior to the onset of capsular thickening and contracture; consequently, the role of imaging is increasing. The aim of this review is to demonstrate the typical imaging appearances of adhesive capsulitis and to examine some of the evidence regarding each of these imaging modalities. An evaluation of the various management options available to the clinician is also presented.

Isolation, structure, and biological activities of Fellutamides C and D from an undescribed Metulocladosporiella (Chaetothyriales) using the genome-wide Candida albicans fitness test.

In a whole-cell mechanism of action (MOA)-based screening strategy for discovery of antifungal agents, Candida albicans was used, followed by testing of active extracts in the C. albicans fitness test (CaFT), which provides insight into the mechanism of action. A fermentation extract of an undescribed species of Metulocladosporiella that inhibited proteasome activity in a C. albicans fitness test was identified. The chemical genomic profile of the extract contained hypersensitivity of heterozygous deletion strains (strains that had one of the genes of the diploid genes knocked down) of genes represented by multiple subunits of the 25S proteasome. Two structurally related peptide aldehydes, named fellutamides C and D, were isolated from the extract. Fellutamides were active against C. albicans and Aspergillus fumigatus with MICs ranging from 4 to 16 µg/mL and against fungal proteasome (IC50 0.2 µg/mL). Both compounds showed proteasome activity against human tumor cell lines, potently inhibiting the growth of PC-3 prostate carcinoma cells, but not A549 lung carcinoma cells. In PC-3 cells compound treatment produced a G2M cell cycle block and induced apoptosis. Preliminary SAR studies indicated that the aldehyde group is critical for the antifungal activity and that the two hydroxy groups are quantitatively important for potency.

Application of affinity selection/mass spectrometry to determine the structural isomer of parnafungins responsible for binding polyadenosine polymerase.

To discover antifungal treatments that possess the desired characteristics of broad spectrum activity, a strong safety profile, and oral bioavailability, new discovery strategies must be implemented to identify structural classes of molecules capable of combating these microorganisms. One such technique that has been implemented is the Candida albicans Fitness Test, a whole cell screening platform capable of delineating the mechanism of action of compounds that demonstrate activity against the clinically relevant pathogenic fungus, C. albicans. Screening crude natural product extracts with this technology has resulted in the identification of a novel family of antifungal natural products, named the parnafungins, which inhibit the enzyme polyadenosine polymerase (PAP), a key component of the mRNA cleavage and polyadenylation complex. Owing to the rapid interconversion of the structural and stereoisomers of the parnafungins at neutral pH, the determination of the structural isomer with the highest affinity for PAP with standard biochemical assays has not been possible. Herein, we present an application of affinity-selection/mass spectrometry (AS-MS) to determine that the "straight" parnafungin structural isomer (parnafungin A) binds preferentially to PAP compared to the "bent" structural isomer (parnafungin B).

PAP inhibitor with in vivo efficacy identified by Candida albicans genetic profiling of natural products.

Natural products provide an unparalleled source of chemical scaffolds with diverse biological activities and have profoundly impacted antimicrobial drug discovery. To further explore the full potential of their chemical diversity, we survey natural products for antifungal, target-specific inhibitors by using a chemical-genetic approach adapted to the human fungal pathogen Candida albicans and demonstrate that natural-product fermentation extracts can be mechanistically annotated according to heterozygote strain responses. Applying this approach, we report the discovery and characterization of a natural product, parnafungin, which we demonstrate, by both biochemical and genetic means, to inhibit poly(A) polymerase. Parnafungin displays potent and broad spectrum activity against diverse, clinically relevant fungal pathogens and reduces fungal burden in a murine model of disseminated candidiasis. Thus, mechanism-of-action determination of crude fermentation extracts by chemical-genetic profiling brings a powerful strategy to natural-product-based drug discovery.

Reduction in late diagnosis of colorectal cancer following introduction of a specialist colorectal surgery service.

INTRODUCTION: An audit of patients presenting with colorectal cancer to our district general hospital during a 2-year period from November 1994 found that 12.1% of cases were diagnosed later than 6 months after initial presentation to a physician. This audit was repeated for a 2-year period from December 2001, to determine whether the introduction of a specialist coloproctology surgery service had led to a reduction in late diagnosis of colorectal cancer. PATIENTS AND METHODS: Case notes were reviewed of all patients presenting with colorectal cancer between December 2001 and November 2003. Late diagnosis was defined as diagnosis of colorectal cancer more than 6 months after their first attendance to either their general practitioner or district general hospital. The results were compared with those of the previous study. RESULTS: Of a total of 218 patients presenting with colorectal cancer during the study period, 14 (6.4%; 10 men and 4 women) satisfied the criteria for late diagnosis, with the longest delay being 12.5 months. Reasons for late diagnosis were false-negative reporting of barium studies (n = 3), inaccurate tumour biopsy (n = 2), concurrent pathology causing anaemia (n = 4), inappropriate delay in definitive investigation (n = 3), and refusal of investigation by patients (n = 2). CONCLUSIONS: There has been a reduction of nearly 50% (12.1% to 6.4%) in the proportion of patients with a late diagnosis of colorectal cancer compared with our previous audit. It is suggested that an important factor in this improvement in diagnosis has been the introduction of a specialist coloproctology surgery service.