Beak sign of recurrent dissection of the thoracic aorta: radiologic-pathologic correlation.
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Biomedical subjects
Publications and source records attributed to J C English.
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Transitional cell carcinoma of the bladder is the most common tumor of the urinary tract. However, it has only been reported twice in the literature to be associated with the paraneoplastic syndrome dermatomyositis. We report a case of amyopathic dermatomyositis in a patient whose painless gross hematuria was due to transitional cell carcinoma of the bladder as well as review this association.
The purpose of this study was to investigate the rate and extent of hydroquinone (HQ) absorption and first pass metabolism in the lungs of male rats in vivo. [14C]HQ in physiological saline was administered intratracheally via an indwelling endotracheal tube to simulate inhalation exposure to HQ dust. The bioavailability of HQ was determined by blood sampling simultaneously at arterial and venous sites beginning immediately after administration to conscious rats. Pulmonary absorption and metabolism, and systemic metabolism and elimination were determined by chromatographic analysis of parent compound and metabolites in blood samples after intratracheal administration of [14C]HQ at 0.1, 1.0, and 10 mg/kg. Pulmonary absorption of HQ was found to be very rapid with [14C]HQ detectable in arterial blood, and to a lesser extent in venous blood, within 5 to 10 s after dose administration. Only [14C]HQ was detected in the initial (5-10 s) arterial blood samples at all dose levels, indicating that pulmonary metabolism of HQ was not extensive. However, later blood samples (45-720 s) indicated rapid metabolism and elimination of the parent compound and metabolites after intratracheal absorption. The elimination half-life from the 0.1 mg/kg dose was allometrically scaled to human proportions and used to estimate the steady-state (maximum) human blood concentrations of HQ resulting from presupposed workplace exposures. The estimates indicated minimal levels of HQ in human blood after respiratory exposures of greater than 1 h at 0.1 or 2.0 mg/m3; these levels were less than background concentrations of HQ detected in human blood in previous studies.
Darier's disease is an autosomal dominant disorder of keratinization that can produce unique clinical manifestations. Oral and topical retinoid products have been the mainstay therapy for this population, but local as well as systemic side effects often limit their effectiveness. A case of localized Darier's disease is presented that responded promptly and with no side effects to the topical application of adapalene 0.1% gel. A review of treatments for Darier's disease is presented.
Basal cell carcinoma is the most common skin malignancy. While this lesion most often occurs in sun-exposed areas of the skin, it can also develop in sites that are not usually exposed to sunlight or artificial ultraviolet radiation, such as the breast, palm or groin. A periodic complete examination of the skin should be performed to ensure that atypical presentations of basal cell carcinoma are not overlooked or misdiagnosed. Treatment options include curettage and desiccation, cryosurgery, surgical excision, radiotherapy and Mohs micrographic surgery.
BACKGROUND: This swine model was designed to elucidate the role of platelet-activating factor in regional myocardial ischemia-reperfusion injury. METHODS: In groups 1 and 2 (n = 12 each), the left anterior descending coronary artery was ligated for 60 minutes to induce regional myocardial ischemia followed by 6 hours of reperfusion. Group 1 received the platelet-activating factor antagonist TCV-309 before ischemia, whereas group 2 did not. Group 3 (n = 3) had a sham operation. RESULTS: Animals in group 2 exhibited significant (p < 0.05) hemodynamic instability and myocardial depression during the reperfusion period. Despite preventive measures, 7 of the 12 animals experienced severe dysrhythmias in the form of atrial and ventricular fibrillation leading to cardiac arrest. In contrast, animals in group 1 in whom the effects of platelet-activating factor were blocked by the specific platelet-activating factor receptor antagonist TCV-309 were hemodynamically stable and had significantly (p < 0.05) better myocardial function. This significant difference in global myocardial function between the groups was observed in the presence of similar morphologic findings and regional myocardial function. CONCLUSIONS: These results suggest that platelet-activating factor has a definite influence on global myocardial dysfunction associated with regional myocardial ischemia-reperfusion injury.
OBJECTIVES: This study was designed to examine the relationship between ex vivo preservation time of the transplanted lung and the extent of injury and to relate this to the severity of rejection with and without allogenicity. METHODS: Single lung transplantation was performed on two groups of domestic swine. Group A (n = 7) and group B (n = 6) had ex vivo preservation times of 4 and 15 hours, respectively, at 4 degrees C hypothermia. Group C (n = 6) underwent 2 hours of warm ischemia via dissection and isolation of the left lung with ligation of its bronchial artery and crossclamping of the left pulmonary artery, vein, and bronchus without explantation. Assessment measures included lung function, antioxidant enzyme activities in the plasma and lung tissue, levels of inflammatory mediators in the recipient plasma, and quantification of major histocompatibility complex II HLA-DR-beta on host peripheral lymphocytes. RESULTS: All groups demonstrated increases in interleukin-10, lung weight, and HLA-DR-1beta expression and decreases in lung-tissue antioxidant enzyme activities, gas exchange, and lung compliance. There was a strong positive correlation between ex vivo preservation time and the expression of HLA-DR-beta and a negative correlation between ischemic time and lung-tissue superoxide dismutase. CONCLUSIONS: These results suggest that the intensity of the host immunogenic response is related to the severity of ischemia-reperfusion injury and is independent of tissue incompatibility and/or the type of ischemic insult. We conclude that the extension of ex vivo preservation time may predispose the transplanted lung to more severe rejection.
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Hydroquinone (HQ) is used in over-the-counter formulations of skin-lightening creams sold in the United States and European Union. HQ was introduced into these formulations to provide a safe and effective alternative to mercury and other less effective ingredients. Recent studies involving subchronic oral exposure of male F344 rats to HQ have shown nephrotoxicity and renal tubule cell proliferation (English et al., 1994), while chronic exposures of male F344 rats were reported to cause renal cell adenomas (NTP, 1989). Previous subchronic dermal toxicity studies (CTFA, 1986; NTP, 1989) with HQ failed to detect nephrotoxicity; however, these studies were not specifically designed to assess renal structure and function. More sensitive endpoints were used in the present subchronic study to address concerns over potential toxicity from repeated dermal exposure to HQ. Male and female F344 rats were given topical applications with 0, 2.0, 3.5, or 5.0% HQ in an oil-in-water emulsion cream for 13 wk (5 days/wk). Body weights, feed consumption and water consumption were monitored, and animals were observed for clinical signs of toxicity and dermal irritation. Blood taken at termination was analysed for haematological and clinical chemistry effects. Erythema, which abated when exposure stopped, was the only dermatological effect seen at the HQ-cream application sites. Cell proliferation in the kidneys was evaluated after 3, 6 and 13 wk of treatment using bromodeoxyuridine (BrdU) labelling, but no changes indicative of sustained cell proliferation were seen. The renal histopathological lesions noted after oral exposure to HQ were not present after dermal exposure. Thus, topical exposure to HQ does not result in the renal toxicity observed in previous studies with F344 rats given HQ orally.
1. Excretion balance studies were conducted with 2-ethylhexanoic acid (EHA) in the female Fischer 344 rat following single high (1 g/kg) or low (0.1 g/kg) oral doses of [2-14C-hexyl]EHA, following repeated oral dosing with unlabelled EHA and a final [14C]EHA oral dose at the low dose level, following dermal exposure with a high (1 g/kg) and low (0.1 g/kg) applied dose of [14C]EHA, and following a 1 mg/kg i.v. dose of [14C]EHA. 2. Oral, i.v. and dermal doses were eliminated rapidly, predominantly in the urine during the first 24 h following dosing. 3. After oral dosing of 0.1 g/kg, the mean peak blood level was 85.1 micrograms equivalents EHA/g. Maximum blood concentrations were detected at either 15 or 30 min in individual animals. After dermal application of 0.1 g/kg, the mean peak blood level of 7.9 micrograms equivalents EHA/g was attained at 8 h. 4. Occlusive dermal exposure caused damage to the epidermis in the first 24 h after application and resulted in dermal absorption of 70% relative to i.v. dosing, based on the ratio of percent dose in excreta. 5. Dermal application followed by prompt washing of the skin resulted in recovery of 101.9% from the skin surface and < 0.2% in the excreta. 6. The major urinary metabolites were the glucuronide of EHA, 2-ethyl-1,6-hexanedioic acid (namely 2-ethyladipic acid), 2-ethyl-5-hydroxyhexanoic acid, 2-ethyl-6-hydroxyhexanoic acid and ethylketohexanoic acid. Evidence for metabolism via beta-oxidation was also found, consistent with the incorporation of EHA into normal cellular intermediary metabolism.
BACKGROUND: Malignant melanoma is the most common metastatic tumor of the gastrointestinal tract and can present with abdominal pain, small bowel obstruction, or occult gastrointestinal bleeding. Diagnosing abdominal pain due to metastatic melanoma is best accomplished by intraluminal studies and computed tomography. Surgical resection of the tumor burden limited to the gastrointestinal tract has been shown to extend periods of palliation in this poor long-term survival group. OBJECTIVES: We will review a case of abdominal pain in a melanoma patient and review the literature.
We asked whether crystalloid administration improves tissue oxygen extraction in endotoxicosis. Four groups of anesthetized pigs (n = 8/group) received either normal saline infusion or no saline and either endotoxin or no endotoxin. We measured whole body (WB) and gut oxygen delivery and consumption during hemorrhage to determine the critical oxygen extraction ratio (ERO2 crit). Just after onset of ischemia (critical oxygen delivery rate), gut was removed for determination of area fraction of interstitial edema and capillary hematocrit. Radiolabeled microspheres were used to determine erythrocyte transit time for the gut. Endotoxin decreased WB ERO2 crit (0.82 +/- 0.06 to 0.55 +/- 0.08, P < 0.05) and gut ERO2 crit (0.77 +/- 0.07 to 0.52 +/- 0.06, P < 0.05). Unexpectedly, saline administration also decreased WB ERO2 crit (0.82 +/- 0.06 to 0.62 +/- 0.08, P < 0.05) and gut ERO2 crit (0.77 +/- 0.07 to 0.67 +/- 0.06, P < 0.05) in nonendotoxin pigs. Saline administration increased the area fraction of interstitial space (P < 0.05) and resulted in arterial hemodilution (P < 0.05) but not capillary hemodilution (P > 0.05). Saline increased the relative dispersion of erythrocyte transit times from 0.33 +/- 0.08 to 0.72 +/- 0.53 (P < 0.05). Thus saline administration impairs tissue oxygen extraction possibly by increasing interstitial edema or increasing heterogeneity of microvascular erythrocyte transit times.
Isopropanol (IPA), as a 70% aqueous solution, was applied under occluded conditions to the shaved backs of male and female Fischer F-344 rats for a period of 4 hr. Maximum analyzed blood concentrations of IPA were attained at 4 hr and decreased steadily following removal of the test material. Blood concentrations were below the limit of quantification at 8 hr. Acetone (ACE) blood levels rose steadily during the 4-hr exposures and continued to rise following removal of the test material, reaching peak analyzed levels at 4.5 hr (male) and 5 hr (females). ACE blood concentrations were below the limit of quantification at 24 hr. Basic pharmacokinetic parameters were similar for male and female rats with mean, first-order elimination half-lives for IPA and ACE of 0.8 to 0.9 hr and 2.1 to 2.2 hr, respectively. Following iv administration of [14C]IPA, 50-55% of the dose was eliminated as 14CO2 with lesser amounts recovered as expired volatiles or in urine. Total recoveries following iv administration were 83% for both males and females. Following a 4-hr dermal exposure to [14C]IPA (70% aqueous solution), 84-86% of the dose was recovered from the application site. Dermal absorption rates were calculated by two independent methods. The values obtained were 0.78 +/- 0.03 and 0.85 +/- 0.04 mg/cm2/hr for males and 0.77 +/- 0.13 and 0.78 +/- 0.16 mg/cm2/hr for females. Calculated permeability coefficients of 1.37 to 1.50 x 10(-3) cm/hr for males and 1.35 to 1.37 x 10(-3) cm/hr for females indicate that in the rat, IPA is rapidly absorbed dermally when applied under occluded conditions.
Hypoprothrombinemic states are commonly treated with injectable vitamin K. Cutaneous vitamin K hypersensitivity can manifest as eczematous or sclerodermoid lesions and historically has been related to the use of fat-soluble vitamin K1. We present a case of warfarin-induced hypoprothrombinemia treated with aqueous vitamin K1, which resulted in the appearance of eczematous vitamin K1 hypersensitivity.
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Cutaneous larva migrans is an intensely pruritic serpiginous eruption caused by the dog or cat hookworm. Often, the disease is self-limiting and no other significant pathology develops; however, a significant localized inflammatory response to the nematode is extremely common. We present a case of cutaneous larva migrans in which a systemic inflammatory process ensued that was characteristic of erythema multiforme. We discuss possible mechanisms of this complication and review the literature.
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A wide range of infectious, neoplastic, and inflammatory dermatoses can affect the glans penis or prepuce. Some are unique to the genitalia. Other more common dermatoses may have a unique appearance when they involve genital skin and mucosa. A thorough understanding of regional anatomy and a systematic diagnostic approach are helpful in the management of a refractory penile dermatosis. We review embryology and regional anatomy, drug-induced eruptions, allergic and irritant dermatitis, infection, neoplasia, and traumatic and inflammatory dermatoses as they relate to the glans and prepuce. Our discussion focuses on the clinical features, office laboratory studies, and histopathologic findings that assist in diagnosis and treatment.