Kingman P. Strohl

Role of hypoxemia in sleep apnea-induced sympathoexcitation

The importance of hypoxemia in determining sympathoexcitation during obstructive sleep apnea was examined by comparing changes in efferent sympathetic nerve activity (SNA) during spontaneous obstructive apneas with hypoxemia alone of similar magnitude and duration induced by 1-4 breaths of 100% nitrogen in six patients with obstructive sleep apnea and with spontaneous apneas while breathing 100% oxygen (apnea without hypoxemia) in three patients. In addition, eight control subjects were studied during induced hypoxemia. The magnitude of sympathoexcitation during spontaneous apneas (103 +/- 15%) was more than twice that observed during induced hypoxemia (47 +/- 14%) during episodes in which the nadir of oxygen desaturation (78 +/- 2 and 75 +/- 2%, respectively) and duration of hypoxemia (27 +/- 3 and 33 +/- 3 s, respectively) were the same (P > 0.20). Similarly, in three patients SNA increased 115% during normoxic spontaneous obstructive apneas, but increased only 43% during hyperoxic spontaneous obstructive apneas in which oxygen saturation did not decrease significantly. Sympathetic neural responses to induced hypoxemia in control subjects (17 +/- 7%) were significantly less than that of the sleep apnea patients. We conclude that hypoxemia contributes importantly, but is not the sole determinant of the sympathoexcitation provoked during episodes of obstructive sleep apnea.

Messenger RNAs for the multifunctional cytokines interleukin‐1α, interleukin‐1β and tumor necrosis factor‐α are present in adnexal tissues and in dermis of normal human skin

Abstract Interleukin‐1α (IL‐1α), interleukin‐1 β (IL‐1β) and tumor necrosis factor‐α (TNF‐α) are 3 cytokines that play a key rôle in cutaneous homeostasis and in the immunopathogenesis of a number of dermatologic diseases. Most studies have focussed on their production by keratino‐cytes and Langerhans cells. To determine whether there are non‐epidermal sites of cytokine transcription, biopsy specimens of normal human skin were probed for IL‐lα, IL‐lβ and TNF‐α messenger RNAs using the method of in situ hybridization. The results demonstrate that each cytokine mRNA is present at multiple sites within the skin, including epidermal appendages and adnexal structures (hair follicles, sebaceous glands), the dermal microvasculature, arrectores pilorum smooth muscle, and the dermal connective tissue. These data provide evidence that in vivo there are multiple sites other than the epidermis of constitutive IL‐lα, 1L‐Iβ, and TNF‐α gene transcription in normal human skin.

Sleep Medicine Training Across the Spectrum

There is now a new pathway and examination for sleep medicine, sponsored by the American Board of Internal Medicine, and a number of accredited sleep medicine fellowship programs through the Accreditation Council for Graduate Medical Education. This review takes an historical approach to discuss the process of education for sleep physiology and disorders not only in the postgraduate period but also at all levels of instruction. In reality, there is a continuum of knowledge that needs to be reinforced up and down the educational system, of which Sleep Medicine subspecialty training is just one part. Although progress has been made at all educational levels up to this point, the future of training and education will depend on a sustained effort at several levels from undergraduate to postgraduate continuing medical education and will be facilitated by professional societies and other specialties who will collectively promote the value of and outcomes for clinical sleep medicine.

A Management Guideline for Obesity-Hypoventilation Syndromes.

A survey of our pulmonary service revealed little consensus as to the definition, work-up, and management of hypoventilation, more often encountered in the presence of obesity. If hypoventilation is defined by an arterial carbon dioxide level above 45mmHg, 22% of artrial blood gas samples over a 5-month period met this criterium, suggesting a high “any-cause” prevalence. This article presents the rationale and explanation for a management protocol for obesity-hypoventilation that is currently being assessed in the VA Medical Center and Case Western Reserve University training program in Pulmonary and Critical Care Medicine.

Occupational allergic rhinitis reaction to psyllium.

We report studies that document a specific rhinitic reaction that developed as a result of occupational exposure to a psyllium-based powdered laxative. This nurse had a nonatopic family history, personal evidence of atopy (skin test reactions to pollen, cat dander, and house dust), and a significant elevation of antipsyllium IgE. Measurements of nasal and lower airway resistance documented only nasal obstruction to brief inhalational challenge to the laxative. Symptomatic relief was achieved with prior treatment with cromolyn. We suggest that nasal airway challenge can document and assess treatment for occupational rhinitis.

In situ changes in the relative abundance of human epidermal cytokine messenger RNA levels following exposure to the poison ivy/oak contact allergen urushiol

Abstract Epidermal keratinocytes in culture have been shown to produce many cytokines, and their proteins have been identified in skin tissue samples. It has therefore been assumed that these cytokines are transcribed in vivo by the epidermis in response to contact allergens. In this report, in situ hybridization was used to detect the messenger RNAs for interleukin‐1 alpha (IL‐1α), interleukin‐1 beta (IL‐1β) and tumour necrosis factor‐alpha (TNF‐α) in samples of human skin prior to and at various times after application of urushiol, the immunogenic component of poison ivy/oak. In sensitive subjects, IL‐1α and TNF‐α mRNAs showed a progressive increase in transcript levels that paralleled the clinical and histological features of the inflammatory process. The time–course of the IL‐1β response differed from that of IL‐1α and TNF‐α, in that there was an early (by 6 h after urushiol administration) elevation in IL‐1 β mRNA that occurred before there was evidence of inflammation and had returned to background levels by 72 h when the reaction had reached its peak. In contrast to urushiol‐sensitive subjects, urushiol‐allergic individuals did not exhibit an increase in IL‐1α. IL‐1β or TNF‐α mRNA levels. The data provide evidence for an in vivo role for epidermal IL‐1α, IL‐1β and TNF‐α transcription in the regulation of IL‐lβ and TNF‐α polypeptide levels in the epidermis in response to this common contact allergen.

Effect of Long‐Term Angiotensin‐Converting Enzyme Inhibitor Therapy on Arterial Oxygen Saturation in Patients With Mild to Moderate Heart Failure

Study Objective. To evaluate the effects of angiotensin‐converting enzyme (ACE) inhibition on continuous pulse oximetry recordings of arterial oxygen saturation (SpO2).