Asymmetrical growth of scalp hair in syringomyelia

Trophic alterations in the skin take place consequent to interruption of its motor, sensory, and autonomic innervation. The hair in denervated areas is often less abundant and grows more slowly. Syringomyelia is a common cause of cutaneous trophic alterations that are often unilateral. They occur predominantly in the upper extremities and seldom involve the skin over the face and scalp. A patient with syringomyelia exhibited a unilateral impairment of pain and temperature sensation in the entire right side of the scalp. A dissimilarity of hair length between the right and left side of the scalp was noticed, with a sharp demarcation along the midline. This peculiar trophic change has not been previously described in the medical literature.     

Two-compartment, two-sample technique for accurate estimation of effective renal plasma flow: theoretical development and comparison with other methods

Discordance between effective renal plasma flow (ERPF) measurements from radionuclide techniques that use single versus multiple plasma samples was investigated. In particular, the authors determined whether effects of variations in distribution volume (Vd) of iodine-131 iodohippurate on measurement of ERPF could be ignored, an assumption implicit in the single-sample technique. The influence of Vd on ERPF was found to be significant, a factor indicating an important and previously unappreciated source of error in the single-sample technique. Therefore, a new two-compartment, two-plasma-sample technique was developed on the basis of the observations that while variations in Vd occur from patient to patient, the relationship between intravascular and extravascular components of Vd and the rate of iodohippurate exchange between the components are stable throughout a wide range of physiologic and pathologic conditions. The new technique was applied in a series of 30 studies in 19 patients. Results were compared with those achieved with the reference, single-sample, and slope-intercept techniques. The new two-compartment, two-sample technique yielded estimates of ERPF that more closely agreed with the reference multiple-sample method than either the single-sample or slope-intercept techniques.     

Acute neurobehavioural effects of toluene

An acute inhalation chamber study of 42 college students was performed to investigate the relation between exposure to 0, 75, and 150 ppm of toluene and changes in central nervous system function and symptoms. Paid subjects were exposed for seven hours over three days. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory); perception (pattern recognition); psychomotor skill (simple reaction time, continuous performance, digit symbol, hand-eye coordination, finger tapping, and critical tracking); manual dexterity (one hole); mood (profile of mood scales (POMS]; fatigue (fatigue checklist); and verbal ability were evaluated at 0800, 1200, and 1600 hours. Voluntary symptoms and observations of sleep were collected daily. An analysis of variance and test for trend was performed on the difference and score for each concentration reflecting an eight hour workday where each subject was their own control. A 3 x 3 Latin square study design evaluated toluene effects simultaneously, controlling for learning across the three days and the solvent order. Intersubject variation in solvent uptake was monitored in breath and urine. A 5-10% decrement in performance was considered significant if it was consistent with a linear trend at p less than 0.05. Adverse performance at 150 ppm toluene was found at 6.0% for digit span, 12.1% for pattern recognition (latency), 5.0% for pattern memory (number correct), 6.5% for one hole, and 3.0% for critical tracking. The number of headaches and eye irritation also increased in a dose response manner. The greatest effect was found for an increasing number of observations of sleep. Overall, no clear pattern of neurobehavioural effects was found consistent with the type 1 central nervous system as classified by the World Health Organisation. Subtle acute effects, however, were found just below and above the ACGIH TLV of 100 ppm toluene, supporting the position that the guideline be lowered since the biological threshold of behavioural effects may be comparable with the TLV.     

Corneal elastosis within lattice dystrophy lesions.

Corneal buttons of two patients with lattice corneal dystrophy were studied by light and electron microscopy. They showed elastotic degeneration within the amyloid deposits. The amyloid deposits displayed characteristic staining; the elastotic material (elastin) within the deposits stained positive with Verhoeff-van Gieson and Movat pentachrome stains and showed autofluorescence. The characteristic ultrastructural findings of amyloid and elastotic material were also demonstrated. The possibility of the associations of these two materials in the cornea is discussed.     

Early detection of extrafoveal neovascular membranes by daily central field evaluation

Argon laser photocoagulation can reduce the risk of severe vision loss in patients with age-related macular degeneration, ocular histoplasmosis, and idiopathic neovascularization. Early detection of neovascularization soon after the onset increases the likelihood of identifying patients with a new vessel membrane in a potentially treatable position. Patients with one or both eyes at risk for the development of a new vessel membrane should assess their central visual fields on a daily basis by occluding first one eye and then the other. Any disturbance in distance vision or reading vision or the appearance of distortion in the patient's field or on the Amsler grid should prompt an eye examination at the earliest feasible time, in an effort to detect neovascularization in a treatable position.     

Diaphanography in the diagnosis of breast cancer

In diaphanography, a light source is applied to the breast to visualize lesions through a television camera sensitive to infrared light. Diaphanography and mammography were performed on 1,476 patients in a screening population. Twenty-six cancers in 24 patients were confirmed by biopsy; detection rates were 96% for mammography, 58% for diaphanography, and 62% for physical examination. Mammography was significantly more sensitive than either diaphanography or physical examination (p less than 0.005). Mammography detected 10 cancers that were missed at physical examination, whereas diaphanography detected five such lesions. It is concluded that diaphanography does not satisfy the criteria of a screening procedure, but because the examination is completely innocuous, it may serve as an adjunct to physical examination. In addition, the authors developed a breast model for diaphanography that appears to correlate with the human breast and demonstrates some of the physics and limitations of diaphanography.     

Adult intrasellar teratoid tumor

Intracranial teratomas rarely occur in adults. The most common sites are the pineal followed by the suprasellar or hypothalamic areas. Infrequently, teratomas can arise within the sella turcica and mimic a pituitary adenoma or craniopharyngioma. Teratoid tumors contain tissue arising from only two of the three primitive germ layers, whereas teratomas have elements of all three. The following case illustrates the unusual occurrence of an intrasellar teratoid tumor in a 33-year-old man.     

Identification of IL-16 as the lymphocyte chemotactic activity in the bronchoalveolar lavage fluid of histamine-challenged asthmatic patients

Objective: We have previously demonstrated that the earliest lymphocyte chemotactic factors present in bronchoalveolar lavage fluid (BALF) of subjects with atopic asthma after subsegmental antigen challenge are IL-16 and MIP-1α, of which IL-16 appears to contribute a majority of the chemotactic activity. Because IL-16 is released in vitro after histamine stimulation of CD8⁺ T cells and epithelial cells, we evaluated the potential role of histamine in the release of IL-16 into the airways of allergic asthmatics in vivo. Methods: Eight allergic asthmatic subjects, six normal subjects, and six atopic nonasthmatic subjects were challenged with saline in the lingula and with serial concentrations of histamine (1 × 10^-7 to 5 × 10^-5 mol/L) in the right middle lobe followed by bronchoalveolar lavage (BAL) 15 minutes and 6 hours later. Results: The BALF from saline- and histamine-challenged lobes of normal subjects and atopic nonasthmatic subjects contained no significant lymphocyte chemoattractant activity. In six of the eight atopic asthmatic subjects, the histamine-challenged but not saline-challenged segment contained IL-16 chemotactic activity but no other identifiable lymphocyte chemoattractant activities at 6 hours. Conclusions: IL-16 appears in the airways after histamine challenge and therefore could contribute to the earliest infiltration of CD4⁺T cells and eosinophils observed after antigen challenge due to histamine release from mast cells. (J Allergy Clin Immunol 1998;101:786-792.)