Surfactant-free liquid-exfoliated copper hydroxide nanocuboids for non-enzymatic electrochemical glucose detection.

To facilitate printable sensing solutions particles need to be suspended and stabilised in a liquid medium. Hansen parameters were used to identify that alcohol-water blends are ideal for stabilising colloidal copper hydroxide in dispersion. The suspended material can be further separated in various size fractions with a distinct cuboid geometry which was verified using atomic force microscopy. This facilitates the development of Raman spectroscopic metrics for determining particle sizes. This aspect ratio is related to the anisotropic crystal structure of the bulk crystallites. As the size of the nanocuboids decreases electrochemical sensitivity of the material increases due to an increase in specific surface area. Electrochemical glucose sensitivity was investigated using both cyclic voltammetry and chronoamperometry. The sensitivity is noted to saturate with film thickness. The electrochemical response of 253 mA M-1 cm-2 up to 0.1 mM and 120 mA cm-2 up to 0.6 mM allow for calibration of potential devices. These results indicate suitability for use as a glucose sensor and, due to the surfactant-free, low boiling point solvent approach used to exfoliate the nanocuboids, it is an ideal candidate for printable solutions. The ease of processing will also allow this material to be integrated in composite films for improved functionality in future devices.

Nail dermoscopy (onychoscopy) findings in the diagnosis of primary onychomycosis: A cross-sectional study.

BACKGROUND: Diagnosis of onychomycosis involves direct microscopic examination with potassium hydroxide, culture or histopathology with periodic acid-Schiff staining. Nail dermoscopy (onychoscopy) is a noninvasive, rapid and easily available diagnostic tool though its utility in onychomycosis remains unexplored. OBJECTIVE: To describe the various onychoscopic patterns and compare its percentage positivity with that of standard potassium hydroxide examination, culture and histopathology in patients with a clinical diagnosis of onychomycosis. METHODS: The study recruited 100 patients with a presumptive clinical diagnosis of onychomycosis. A detailed history, physical examination including that of nails and clinical photography was followed by onychoscopy with DermLite DL3. The nail clippings were sent for direct microscopic examination with potassium hydroxide, mycological culture and histopathology with periodic acid-Schiff stain. The patient was said to have onychomycosis if at least one of the three tests was positive. RESULTS: Onychomycosis was confirmed by potassium hydroxide and/or culture and/or histopathology in 88 patients. Onychoscopic features were identified and their association with different clinical variants of onychomycosis was attempted. Percentage positivity for diagnosing onychomycosis in decreasing order was: direct microscopic examination with potassium hydroxide followed by spiked pattern, subungual hyperkeratosis, distal irregular termination on onychoscopy, histopathology, mycological culture and ruins aspect again observed on onychoscopy. LIMITATIONS: Small sample size. CONCLUSIONS: Many onychoscopic features are highly specific for different variants of onychomycosis so onychoscopy may serve as an important and quick adjunct to diagnose onychomycosis until other time-consuming investigations, such as culture and periodic acid-Schiff become available. Studies on a larger population will help arrive at a logistic conclusion.

Subungual hyperkeratosis nail biopsy: a better diagnostic tool for onychomycosis.

BACKGROUND: Onychomycosis is one of the most common nail disorders. Mycological examination by potassium hydroxide (KOH) mount and fungal culture is the most commonly used diagnostic method. However, it is associated with a low sensitivity. AIMS: To evaluate the technique of subungual hyperkeratosis nail biopsy in diagnosing onychomycosis in HIV-infected and immunocompetent adults and compare it with mycological examination. METHODS: 34 HIV-positive patients who presented clinically with onychomycosis were recruited in the study from the beginning. There was no screening done for patients with onychomycosis. This has been clarified in manuscript under the heading of methods. RESULTS: All the fungal cultures yielded dermatophytes correlating with the biopsy findings. Only hyphal form of fungus was detected in KOH examination, indicating it was not a contaminant. Clinical types of onychomycosis are stated in discussion. CONCLUSIONS: PAS stain of subungual hyperkeratosis nail biopsy was the most sensitive in the diagnosis of onychomycosis in both HIV-infected and non-infected groups.

Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis.

BACKGROUND: Onychomycosis is a common problem noticed in clinical practice. Currently available standard laboratory methods show inconsistent sensitivity; hence there is a need for newer methods of detection. AIMS: This study involves comparison of standard laboratory tests in the diagnosis of onychomycosis, namely, potassium hydroxide mount (KOH mount) and mycological culture, with histopathologic examination using periodic acid-Schiff (PAS) staining of the nail clippings. METHODS: A total of 101 patients with clinically suspected onychomycosis were selected. Nail scrapings and clippings were subjected to KOH mount for direct microscopic examination, culture using Sabouraud's dextrose agar (with and without antibiotics) and histopathologic examination with PAS staining (HP/PAS). Statistical analysis was done by McNemar's test. RESULTS: Direct microscopy with KOH mount, mycological culture, and HP/PAS showed positive results in 54 (53%), 35 (35%), and 76 (75%) patients respectively. Laboratory evidence of fungal infection was obtained in 84 samples by at least one of these three methods. Using this as the denominator, HP/PAS had a sensitivity of 90%, which was significantly higher compared to that of KOH mount (64%) or mycological culture (42%). CONCLUSIONS: Histopathologic diagnosis with PAS staining of nail clippings was the most sensitive among the tests. It was easy to perform, rapid, and gave significantly higher rates of detection of onychomycosis compared to the standard methods, namely KOH mount and mycological culture.

An open, nonrandomized, comparative study of imiquimod 5% cream versus 10% potassium hydroxide solution in the treatment of molluscum contagiosum.

BACKGROUND: There are numerous therapeutic modalities available for treatment of molluscum contagiosum. However, the ablative modalities are painful and not suitable for children. AIM: We aimed to evaluate and compare the safety and efficacy of 2 of the painless modalities, viz., 5% imiquimod cream and 10% potassium hydroxide (KOH) solution, in the treatment of molluscum contagiosum. METHODS: Out of a total of 40 patients of molluscum contagiosum in the study, 18 patients in the imiquimod group and 19 patients in the KOH group completed the study. The given medication was applied by the patient or a parent to mollusca at night, 3 days per week. Imiquimod was continued till clinical cure; and 10% KOH, till lesions showed signs of inflammation. Assessments of response and side effects were performed at the end of week 4, week 8, and week 12. Significance was tested by Student's t test and Mann-Whitney test. RESULTS: The mean lesion count decreased from 22.39 to 10.75 with imiquimod and from 20.79 to 4.31 with KOH at the end of 12 weeks. We found complete clearance of lesions in 8 (44%) patients with imiquimod and in 8 (42.1%) patients with 10% KOH. Minor side effects were seen in 15 (78.9%) patients on KOH and 10 (55.5%) patients on imiquimod. CONCLUSIONS: The results of this study suggest that both 5% imiquimod cream and 10% KOH solution are equally effective in molluscum contagiosum though KOH has a faster onset of action. However, KOH solution is associated with a higher incidence of side effects.

Physico-chemical determinants of dermal drug delivery: effects of the number and substitution pattern of polar groups.

The aim of this study was to investigate the effect of number and substitution pattern of -OH groups of a set of phenols on the in vitro permeation of heat-separated human epidermis. The diffusion was calculated from Log(D/x)=logk(p)-0.59logK(oct)+0.024 (D, diffusion coefficient; x, pathlength; k(p), permeability coefficient (cm/h); and K(oct), octanol-water partition coefficient). The main factors reducing D were the dipolar and hydrogen bonding capabilities of the permeants quantified as their Hansen partial solubility parameters delta(p) and delta(h). These parameters are significantly reduced by the degree of symmetry of the molecule, so that phloroglucinol (1,3,5-benzenetriol), with three -OH groups, diffuses more rapidly that phenol. When symmetry is absent, as in 1,2,4-benzenetriol, the number of -OH groups results in very slow diffusion. D/x (cm/h) was related to the combined solubility parameter delta(a) defined as radical(delta(p)(2)+delta(h)(2)) by: (D/x)=0.0024-0.000065delta(a) (n=7, R(2)=0.70, P=0.012).

Microbial glycolipids: possible virulence factors that scavenge oxygen radicals.

Two important pathogens of developing countries, Mycobacterium leprae, the etiologic agent of leprosy, and Leishmania donovani, the protozoal parasite that causes kalaazar, persist in the human host primarily in mononuclear phagocytes. The mechanisms by which they survive in these otherwise highly cytocidal cells are presently unknown. Since the best understood cytocidal mechanism of these cells is the oxygen-dependent system that provides lethal oxidants including the superoxide anion (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH), and singlet oxygen (1O2), we sought specific microbial products of these organisms that might enable them to elude oxidative cytocidal mechanisms. Phenolic glycolipid I of M. leprae and lipophosphoglycan of L. donovani are unique cell-wall-associated glycolipids produced in large amounts by the organisms. In this study, phenolic glycolipid I derivatives and lipophosphoglycan were examined for their ability to scavenge potentially cytocidal oxygen metabolites in vitro. Electron spin resonance and spin-trapping indicate that phenolic glycolipid I derivatives and lipophosphoglycan are highly effective in scavenging hydroxyl radicals and superoxide anions. The results suggest that complex glycolipids and carbohydrates of intracellular pathogens that can scavenge oxygen radicals may contribute to their pathogenicity and virulence.

Oxygen metabolism in phagocytes of leprotic patients: enhanced endogenous superoxide dismutase activity and hydroxyl radical generation by clofazimine.

We examined the generation of active oxygens (O2-, H2O2, and OH X ) and the superoxide dismutase (SOD) activity of polymorphonuclear leukocytes (PMNs) and monocytes from 14 leprotic patients manifesting a bacillary index above 2.2. Patients with disease of more than 4 years in duration showed significantly enhanced SOD activity and a decrease in O2- and OH X production. The antileprotic agent, clofazimine, significantly increased the generation of OH X in a dose-dependent manner, with a subsequent decrease in H2O2, but had no effect on the SOD activity of the PMNs and monocytes. In medium containing FeSO4 or Fe2+-EDTA, the drug elevated OH X production markedly further. Phagocytic SOD in PMNs and monocytes of leprotic patients was both host and bacillus derived, because the presence of cyanide, to which human-derived cuprozinc SOD is susceptible, did not completely abrogate SOD activity. The difficulty in treating leprosy may be partly ascribable to decreased phagocytic OH X generation, which in leprosy patients is apparently due to the uptake of Hansen bacillus-derived SOD. Clofazimine may be effective in leprosy by chelating Fe2+, with the resultant potentiation of the catalyzing activity of Fe2+ in the Haber-Weiss reaction increasing OH X formation from H2O2.