J Comp Neurol. 1997 Nov 3;387(4):489-506.
Overexpression of nerve growth factor in skin causes preferential increases among innervation to specific sensory targets.
Davis BM, et al
The impact of increased levels of skin-derived nerve growth factor (NGF) neurotrophin on sensory and sympathetic innervation to the mouse mystacial pad and postero-orbital vibrissae was determined. Consistent with an approximate doubling of neuron number in trigeminal and superior cervical ganglia, many components of the sensory and sympathetic innervation were substantially enhanced. Although the increased number of neurons raised the possibility that all types of innervation were increased, immunohistochemical analysis indicated that enhanced NGF production had a differential effect upon sensory innervation, primarily increasing unmyelinated innervation. This increased innervation occurred in specific locations known to be innervated by small, unmyelinated fibers, suggesting that NGF modulated sensory innervation density, but not targeting. In contrast, sympathetic innervation was not only increased but also was distributed to some aberrant locations. In the intervibrissal fur of the mystacial pad, both the number of sensory axons and branches appeared increased, whereas in vibrissal follicle sinus complexes, only branching increased. In some areas, sensory ending density was lower than expected based upon the size of the source nerve bundles suggesting that many axons and branches were surviving but failing to form functional endings. Furthermore, the immunochemical profile of innervation was altered in some sensory populations as demonstrated by the coexistence of RT-97 neurofilament labeling in calcitonin gene-related peptide (CGRP) positive axons, by the loss of substance P colocalization in some CGRP axons, and by an absence of neuropeptide Y labeling in tyrosine hydroxylase positive sympathetic axons. Collectively, these results indicate that the NGF mediated increase in neuron number may be selective for particular sets of innervation and that increases among some populations may result from phenotypic switching.
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JAMA Dermatol. 2013 May 22:1-5. doi: 10.1001/jamadermatol.2013.3049. [Epub ahead of print]
Autoimmune, Atopic, and Mental Health Comorbid Conditions Associated With Alopecia Areata in the United States.
Huang KP, Mullangi S, Guo Y, Qureshi AA.
Abstract
OBJECTIVE To evaluate the prevalence of comorbid conditions among patients with alopecia areata (AA) seen at tertiary care hospitals in Boston, Massachusetts, during an 11-year period. DESIGN Retrospective cross-sectional study. SETTING Tertiary care hospitals in Boston, including Brigham and Women's Hospital and Massachusetts General Hospital. PARTICIPANTS We identified 3568 individuals with AA seen in the Partners health care system in Boston between January 1, 2000, and January 1, 2011. We performed comprehensive searches of the Research Patient Data Repository using International Classification of Diseases, Ninth Revision code 704.01. We randomly selected 350 patients and manually reviewed their medical records to train and validate a novel artificial intelligence program. This program then used natural language processing to review free-text medical records and confirm a diagnosis of AA. To confirm the algorithm, we manually reviewed a subset of records and found 93.9% validity. MAIN OUTCOMES AND MEASURES The prevalence of comorbid conditions was assessed. RESULTS Common comorbid conditions included autoimmune diagnoses (thyroid disease in 14.6%, diabetes mellitus in 11.1%, inflammatory bowel disease in 6.3%, systemic lupus erythematosus in 4.3%, rheumatoid arthritis in 3.9%, and psoriasis and psoriatic arthritis in 2.0%), atopy (allergic rhinitis, asthma, and/or eczema in 38.2% and contact dermatitis and other eczema in 35.9%), and mental health problems (depression or anxiety in 25.5%). We also found high prevalences of hyperlipidemia (24.5%), hypertension (21.9%), and gastroesophageal reflux disease (17.3%). This profile was different from that seen in a comparison psoriasis and psoriatic arthritis group. CONCLUSIONS AND RELEVANCE We found a high prevalence of comorbid conditions among individuals with AA presenting to academic medical centers in Boston. Physicians caring for patients with AA should consider screening for comorbid conditions.
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Adv Nurse Pract. 1999 Apr;7(4):39-42, 83. Hair-raising. The latest news on male-pattern baldness.
Proctor PH.
The initiating event in balding seems to be an abnormal sensitivity to the male sex hormones. In addition, a multifactorial model is emerging in which hormones affect the hair follicle in a way that causes it to be perceived as a foreign body by the immune system, which then mounts an attack. Several new classes of agents have the potential to treat hair loss. More than 40 U.S. and several hundred foreign patents have been issued for hair-loss treatment agents. As is common in dermatology, no single agent works universally against hair loss, so the treatment process is often one of trial and error.
This is a paper by Dr. Proctor