There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

Harrison's Principles of Internal Medicine

Secret History: Return of the Black Death Channel 4, 7-8pm In 1348 the Black Death swept through London, killing people within days of the appearance of their first symptoms. Exactly how many died, and why, has long been a mystery. This Secret History documentary follows experts as they pick through the evidence and reveal why the plague killed on such a scale. And they ask, what might be coming next?

Medscape

Chronic urticaria. I

Wound care is a major healthcare expenditure. Treatment of burns, surgical and trauma wounds, diabetic lower limb ulcers and skin wounds is a major medical challenge with current therapies largely focused on supportive care measures. Successful wound repair requires a series of tightly coordinated steps including coagulation, inflammation, angiogenesis, new tissue formation and extracellular matrix remodelling. Zinc is an essential trace element (micronutrient) which plays important roles in human physiology. Zinc is a cofactor for many metalloenzymes required for cell membrane repair, cell proliferation, growth and immune system function. The pathological effects of zinc deficiency include the occurrence of skin lesions, growth retardation, impaired immune function and compromised would healing. Here, we discuss investigations on the cellular and molecular mechanisms of zinc in modulating the wound healing process. Knowledge gained from this body of research will help to translate these findings into future clinical management of wound healing.

https://www.mdpi.com/2072-6643/10/1/16/pdf/1

Zinc in Wound Healing Modulation.

Zinc, both in elemental or in its salt forms, has been used as a therapeutic modality for centuries. Topical preparations like zinc oxide, calamine, or zinc pyrithione have been in use as photoprotecting, soothing agents or as active ingredient of antidandruff shampoos. Its use has expanded manifold over the years for a number of dermatological conditions including infections (leishmaniasis, warts), inflammatory dermatoses (acne vulgaris, rosacea), pigmentary disorders (melasma), and neoplasias (basal cell carcinoma). Although the role of oral zinc is well-established in human zinc deficiency syndromes including acrodermatitis enteropathica, it is only in recent years that importance of zinc as a micronutrient essential for infant growth and development has been recognized. The paper reviews various dermatological uses of zinc.

/pdf/zinc-therapy-in-dermatology-a-review-12gq8lknl0.pdf

Zinc therapy in dermatology: a review.

Peroxisome proliferator-activated receptors (PPARs) are nuclear hormone receptors and comprise three different isoforms namely PPARα, PPARγ, and PPARβ/δ with PPARβ/δ being the predominant subtype in human keratinocytes. After binding with specific ligands, PPARs regulate gene expression, cell growth and differentiation, apoptosis, inflammatory responses, and tumorogenesis. PPARs also modulate a wide variety of skin functions including keratinocyte proliferation, epidermal barrier formation, wound healing, melanocyte proliferation, and sebum production. Recent studies have shown the importance of PPARs in the pathogenesis of many dermatological disorders. Clinical trials have suggested possible role of PPAR agonists in the management of various dermatoses ranging from acne vulgaris, psoriasis, hirsutism, and lipodystrophy to cutaneous malignancies including melanoma. This article is intended to be a primer for dermatologists in their understanding of clinical relevance of PPARs and PPAR agonists in dermatology therapeutics.

Peroxisome proliferator-activated receptors (PPARs) and PPAR agonists: the ‘future’ in dermatology therapeutics?

SummaryBackground
Tranexamic acid (TXA) has been used orally, intravenously, topically and intradermally (microinjection, microneedling) for treating melasma. However, the comparative efficacy of these different routes of administration remains underevaluated.

Aim
To ascertain the comparative efficacy of different routes of administration of TXA.

Methods
In total, 100 consecutive patients with melasma (8 men, 92 women, age range 18–55 years) were randomly assigned to one of two groups comprising 50 patients each. Group A (3 men, 47 women) received oral TXA 250 mg twice daily, while group B (5 men, 45 women) received intradermal microinjections of TXA 4 mg/mL every 4 weeks. The treatment continued for 12 weeks in both groups. Percentage reduction in baseline Melasma Area and Severity Index (MASI) was assessed at 4-week intervals, and response was scored as very good (> 75% reduction), good (50% to < 75% reduction), moderate (25% to < 50% reduction), mild (< 25% reduction) or no response.

Results
The study was completed by 39 patients in group A and 41 patients in group B. Very good response was seen in 25 and 32 patients in groups A and B, respectively, while good response was seen in 14 and 9 patients, respectively. Both treatment methods were equally effective, with an average reduction of MASI at 12 weeks of 77.96 ± 9.39 in group A and 79.00 ± 9.64 in group B. The main adverse effects were mild epigastric discomfort, hypomenorrhea, headache and injection site pain, which did not warrant discontinuation of treatment. Two patients in group A had relapses at 24 weeks.

Conclusion
TXA appears to be an effective and safe treatment for melasma, irrespective of its route of administration.

Therapeutic efficacy and safety of oral tranexamic acid and that of tranexamic acid local infiltration with microinjections in patients with melasma: a comparative study

Background: We studied clinico-epidemiological features of 945 patients with vitiligo with an objective to delineate epidemiological and clinical aspects of vitiligo from this part of the country. Materials and Methods: The medical records of patients with vitiligo attending outpatient clinic over a 5-year period from January 2013 to December 2017 were analyzed retrospectively for this descriptive, observational study. Results: There were 449 men and 496 women (m:f 1:1.1) aged between 2 and 83 years (mean 24.4 years) and having vitiligo for 1 week to 64 years (mean 5.1 years). The majority, 478 (50.6%) patients were aged ≤20 years and 248 (26.2%) were children aged ≤12 years. The age at the onset was between 6 months and 82 years (mean 20.5 years), and the majority 674 (71.3%) patients had it before 25 years of age. The consultation time was within 5 years in 692 (73.2%) patients. A family history of vitiligo was present in 150 (15.9%) patients. The majority 871 (92.2%) patients had involvement of up to 10% body surface area and vitiligo vulgaris in 562 (59.5%) and focal vitiligo in 117 (18.7%) patients were the most common clinical types. An association with other systemic disorders was in 124 (13.1%) patients and predominately included thyroid abnormalities and diabetes mellitus. Conclusions: Our observations are essentially consistent with the literature. There was no difference in clinico-epidemiological features of vitiligo. Patients with an affected first-degree family member had early onset, but difference was not statistically significant. Screening for concurrent thyroid disorders appears important. However, our inferences remain limited by single center, retrospective, observational, and cross-sectional nature of the study.

Clinico-epidemiological profile of patients with vitiligo: A retrospective study from a tertiary care center of North India

Background

Subcutaneous phaeohyphomycosis usually results from traumatic inoculation with the fungus and generally occurs in immunosuppressed men. Cladosporium, Exophiala, and Alternaria spp. are commonly implicated pathogens.



Objectives

We present a case of subcutaneous phaeohyphomycosis caused by Rhytidhysteron sp. that was refractory to conventional antifungal therapy.



Case report

A 72-year-old man with hypertension and diabetes presented with a multiloculated, large cystic swelling over the right dorsal foot. Laboratory findings and x-rays of the chest and left foot were normal.



Results

Adequate control of the patient's diabetes was achieved, and the swelling was excised under itraconazole/terbinafine coverage. Histology showed multiple areas of neutrophilic abscess, epithelioid cells, foreign body giant cells, and multiple septate hyphae and yeast-like cells. Dematiaceous fungus was cultured but failed to produce spores. Sequencing of the isolate showed a match of > 99% with Rhytidhysteron rufulum. The patient demonstrated no response after one year of therapy with itraconazole/terbinafine. Weekly infiltration of the lesion with liposomal amphotericin B resulted in its complete resolution within 15 weeks.



Conclusions

Lesions of phaeohyphomycosis appear morphologically similar regardless of the organism implicated. Hence, their diagnosis rests entirely on the clinicopathological and microbiological presentation. Molecular studies may be required to identify a fungus if attempts to grow it in artificial culture media fail. Rhytidhysteron spp. are not known as pathogens in humans, and no treatment protocol exists. Intralesional amphotericin was highly effective in our patient and caused no systemic adverse effects. Voriconazole and posaconazole are effective against disseminated/visceral phaeohyphomycotic infections, but their efficacy against Rhytidhysteron spp. remains unstudied.

Pushpinder S Chauhan

Papers

Zinc therapy in dermatology: a review.

Peroxisome proliferator-activated receptors (PPARs) and PPAR agonists: the ‘future’ in dermatology therapeutics?

Therapeutic efficacy and safety of oral tranexamic acid and that of tranexamic acid local infiltration with microinjections in patients with melasma: a comparative study

Clinico-epidemiological profile of patients with vitiligo: A retrospective study from a tertiary care center of North India

A rare case of subcutaneous phaeohyphomycosis caused by a Rhytidhysteron species: a clinico-therapeutic experience.