Sporadic congenital leukonychia with partial phenotype expression

GOAL

To describe the characteristics and inheritance pattern of a case of congenital leukonychia.

OBJECTIVES

1. To describe the etiologies of congenital and acquired leukonychia. 2. To discuss the differential diagnosis of leukonychia. 3. To outline inheritance patterns associated with leukonychia.

Development of a physiologically based pharmacokinetic model for hydroquinone

Hydroquinone (HQ) produces nephrotoxicity and renal tubular adenomas in male F344 rats following 2 years of oral dosing. Female F344 and SD rats are comparatively resistant to these effects. Nephrotoxicity and tumorigenicity have been associated with a minor glutathione conjugation pathway following the oxidation of HQ to benzoquinone (BQ). The majority of administered doses (90-99%) consists of glucuronide and sulfate conjugates of HQ. An initial physiologically based pharmacokinetic model was developed to characterize the role of kinetics in the strain differences observed in HQ-induced renal toxicity and tumorigenicity. Partition coefficients, protein-binding, and metabolic rate constants were determined directly or estimated from a series of in vivo and in vitro studies. Metabolism was confined to the liver and GI tract. The total flux through the glutathione pathway represented the "internal dose" of HQ for nephrotoxicity. Simulations were compared to a variety of data from male and female F344 rats, male SD rats, and a single male human volunteer. Simulations of intraperitoneal administration resulted in higher amounts of glutathione conjugates than comparable oral doses. This was consistent with protein-binding and toxicity studies and emphasized the importance of first-pass GI tract metabolism. In addition, male F344 rats were predicted to form more total glutathione conjugates than SD rats at equivalent dose levels, which was also consistent with the observed strain differences in renal toxicity. This model represents the first stage in the development of a biologically based dose-response model for improving the scientific basis for human health risk assessments of HQ.

Therapeutic potential of platelet-activating factor antagonism in the management of myocardial infarction

BACKGROUND

Antagonists of platelet-activating factor (PAF) reduce myocardial postischemia reperfusion injury when given before the onset of ischemia. However, the effects of PAF antagonists when administered at a clinically modelled time (during ischemia but before reperfusion) are controversial. Moreover, the extended survival (eight day) and the characteristics of scar formation after treatment with PAF antagonists have not been investigated.

OBJECTIVES

To determine the therapeutic potential of PAF antagonist TCV-309 for the treatment of regional myocardial ischemia-reperfusion injury; and to determine the effects of TCV-309 on cardiovascular recovery, evolution of scar formation and survival eight days after a myocardial infarction treated with reperfusion.

ANIMALS AND METHODS

Swine underwent regional myocardial ischemia for 60 mins by ligation of the left anterior descending coronary artery, followed by reperfusion for eight days. The treated group (n=7) received PAF antagonist TCV-309 (0.1 mg/kg) 45 mins after ligation; the untreated group (n=7) received vehicle only.

RESULTS

Untreated animals experienced significantly (P<0.001) lower systemic arterial blood pressure during the reperfusion period than animals treated with TCV-309. Furthermore, untreated animals required significantly more (P<0.01) antiarrhythmic and inotropic support. Only two of seven animals in the untreated group survived, which was significantly different (P<0.05) from the six of seven treated animals that survived for eight days. Morphometric analyses did not show differences between groups in the characteristics of scar formation following reperfusion for eight days.

CONCLUSIONS

PAF antagonist TCV-309 improves survival and reduces cardiovascular dysfunctions associated with regional myocardial ischemia reperfusion injury when administered at a clinically modelled time.

Family approach for estimating reference concentrations/doses for series of related organic chemicals

The family approach for related compounds can be used to evaluate hazard and estimate reference concentrations/doses using internal dose metrics for a group (family) of metabolically related compounds. This approach is based upon a simple four-step framework for organizing and evaluating toxicity data: 1) exposure, 2) tissue dosimetry, 3) mode of action, and 4) response. Expansion of the traditional exposure-response analysis has been increasingly incorporated into regulatory guidance for chemical risk assessment. The family approach represents an advancement in the planning and use of toxicity testing that is intended to facilitate the maximal use of toxicity data. The result is a methodology that makes toxicity testing and the development of acceptable exposure limits as efficient and effective as possible. An example is provided using butyl acetate and its metabolites (butanol, butyraldehyde, and butyrate), widely used chemicals produced synthetically by the industrial oxo process. A template pharmacokinetic model has been developed that comprises submodels for each compound linked in series. This preliminary model is being used to coordinately plan toxicity studies, pharmacokinetic studies, and analyses to obtain reference concentrations/doses. Implementation of the family approach using pharmacokinetic modeling to obtain tissue dose metrics is described and its applications are evaluated.

Gingival lesions and nasal obstruction in an immunosuppressed patient post-liver transplantation

Although rare, metastatic hepatocellular carcinoma (HCC) presenting only to the mandible, gingiva, and nasal cavity in patients subsequently found to have primary HCC has been reported. In the age of transplantation, certain HCC patients may receive treatment with an orthotopic liver transplant. Due to the proclivity of HCC for early micrometastases, immunosuppressive therapy can induce significant metastatic lesions. Nasal mass obstruction, gingival lesions, or facial growths in this population must be considered metastatic until proven otherwise.

Presternal bronchogenic sinus with predunculated lymphoid aggregate

Congenital cranial, cervical, and upper thoracic sinuses are rare conditions that historically have been classified according to their location and/or pathology. However, published reports of bronchogenic or branchial anomalies are on the increase, and the traditional defining characteristics--location and histopathology--are proving to be less reliable. We describe the pathologic and clinical findings of a congenital presternal pedunculated lesion with a sinus, and review the literature to describe its proper classification.

Effective treatment of localized Darier's disease with adapalene 0.1% gel

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.

Bioavailability and metabolism of hydroquinone after intratracheal instillation in male rats

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.

Amyopathic dermatomyositis associated with transitional cell carcinoma of the bladder

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.

Effect of crystalloid administration on oxygen extraction in endotoxemic pigs

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.

Recurrence of intravenous talc granulomatosis following single lung transplantation

Advanced pulmonary disease is an unusual consequence of the intravenous injection of oral medications, usually developing over a period of several years. A number of patients with this condition have undergone lung transplantation for respiratory failure. However, a history of drug abuse is often considered to be a contraindication to transplantation in the context of limited donor resources. A patient with pulmonary talc granulomatosis secondary to intravenous methylphenidate injection who underwent successful lung transplantation and subsequently presented with recurrence of the underlying disease in the transplanted lung 18 months after transplantation is reported.

Abdominal pain in a patient with melanoma

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.

Cutaneous larva migrans complicated by erythema multiforme

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.

Metabolism of 2-ethylhexanoic acid administered orally or dermally to the female Fischer 344 rat

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.

Lack of nephrotoxicity and renal cell proliferation following subchronic dermal application of a hydroquinone cream

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.

The role of platelet-activating factor in regional myocardial ischemia-reperfusion injury

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.

The relationship of ischemia-reperfusion injury of transplanted lung and the up-regulation of major histocompatibility complex II on host peripheral lymphocytes

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.

Axillary basal cell carcinoma: a need for full cutaneous examination

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.

Dermal absorption and pharmacokinetics of isopropanol in the male and female F-344 rat

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.

Eczematous hypersensitivity from aqueous vitamin K injection

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.

A new platelet-activating factor antagonist (CV-6209) in preservation of heart and lung for transplantation

The objective of this experimental protocol was to evaluate the protective effect of a new, potent platelet-activating factor (PAF) antagonist CV-6209 and the use of this compound in combination with allopurinol on ischemia-reperfusion injury in a swine model of heart-lung transplantation. Forty-two swine were divided into three groups, with seven donors and seven recipients in each. In group A, the PAF antagonist CV-6209 was administered in a single dosage of 1 mg/kg by slow intravenous injection at 1 hour before crossclamping of the aorta in both donors and recipients. In group B the combination of allopurinol and the PAF antagonist CV-6209 was used. Allopurinol was administered as a pretreatment regime of 50 mg/kg/day for 3 days prior to ischemia. The PAF antagonist dosage and regime of administration were the same as in group A, and both donors and recipients were pretreated with this combination. Group C was the control in which heart-lung transplantations were performed without interventional therapies. Based on the comparison of pre- and post-transplantation assessments of cardiac and pulmonary functional integrity within groups, and post-transplantation among groups, animals in groups A and B were significantly (P < 0.05) better protected from ischemia-reperfusion injury than animals in group C. The difference between groups A and B, however, was insignificant at all times. Morphological findings are in agreement with measures of physiological variation among experimental groups. It is suggested that the new PAF antagonist CV-6209 is effective in the prevention of heart and lung ischemia-reperfusion injury with and without allopurinol pretreatment.

Autoimmune idiopathic thrombocytopenic purpura with the subsequent occurrence of systemic lupus erythematosus

Cutaneous manifestations of petechiae, purpura, and ecchymosis can lead the physician to discover an underlying platelet abnormality. Autoimmune idiopathic thrombocytopenic purpura (AITP) is a diagnosis of exclusion, mediated by a destructive IgG antibody response to the platelets' membrane components. In addition to showing evidence of cutaneous and mucosal bleeding (ie, epistaxis, hematuria), patients with AITP are at an increased risk for systemic lupus erythematosus (SLE). Therefore, it is suggested that patients with AITP be closely monitored for SLE.

Dermatoses of the glans penis and prepuce

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.

Mees' lines in a patient with multiple parasitic infections

Mees' lines, or transverse striate leukonychia, are classically associated with arsenic poisoning, but have been described in other cases of acute or chronic illness. Their pathogenesis is thought to be a disruption of nail plate keratinization secondary to systemic stress. Mees' lines are observed in a patient with helminthic and amebic infections and no history of arsenic exposure. This case demonstrates another clinical setting in which Mees' lines can appear, providing further evidence that Mees' lines may chronicle systemic disease.

Right outflow tract obstruction by a pedunculated neurofibroma: case report and literature review

Right outflow tract obstruction due to neurofibroma is rare, with only four cases identified in the world literature. Obstruction due to a pedunculated neurofibroma has never been reported. A 36-year-old woman with no known heart disease presenting with dyspnea, palpitations and chest pain was shown on echocardiogram to have a mobile right ventricular mass. Cardiac catheterization revealed normal coronary arteries and right ventricular outflow tract obstruction by a pedunculated mass, which was surgically removed and histologically proven to be a benign neurofibroma. Following surgery the patient's symptoms disappeared, with no recurrence three years postoperatively.

Relationship of hydroquinone-associated rat renal tumors with spontaneous chronic progressive nephropathy

Hydroquinone exposure has been reported by the National Toxicology Program (NTP) to produce renal tubule adenomas and to exacerbate spontaneous chronic progressive nephropathy (CPN) in male F344 rats. A mechanism for hydroquinone-related tumorigenesis has not been established, but CPN is known to involve, and hydroquinone produces, enhanced renal tubule cell proliferation. Through an independent review of the renal histopathology from the NTP study, the grade of CPN and the presence of atypical tubule hyperplasia and adenomas was evaluated. Hydroquinone exposure in males at 50 mg/kg, produced a statistically significant increase in the grade of CPN. At 0, 25, and 50 mg/kg, 0/44, 4/49, and 15/51 male rats had either atypical tubule hyperplasias or adenomas; all were within areas of severe or end-stage CPN and were statistically significantly associated with CPN grade. Additionally, there was a dose-related increase in profiles believed to represent new tubule proliferation within areas of advanced CPN, as well as an apparent expansion of these into unusual complex tubule profiles in end-stage kidneys of the high-dose male group. In summary, this histopathological review suggest a mechanism for hydroquinone-related adenoma formation that includes enhancement of the severity of CPN coupled with stimulation of tubule proliferation.

Cutaneous hyperpigmentation and polyglandular autoimmune syndrome type II

Primary adrenal insufficiency (Addison's disease) may initially present with cutaneous hyperpigmentation. Addison's disease, when associated with autoimmune thyroid disease and/or insulin-dependent diabetes mellitus, is referred to as polyglandular autoimmune syndrome type II. We present the case of a patient who initially was diagnosed as having Grave's disease and eventually Addison's disease due to persistent cutaneous hyperpigmentation, fatigue, weight loss, hypotension, hyponatremia, peripheral eosinophilia, and positive results of a synthetic corticotropin stimulation test. Addison's disease, polyglandular autoimmune syndrome type II, and cutaneous hyperpigmentation are reviewed.

Acrospiroma: a case report and review

Acrospiromas are cutaneous tumors of sweat duct differentiation. They usually present as slowly enlarging 1 to 2 cm nodules in middle-aged or older adults without site predilection. On histologic examination they are multilobular dermal masses composed of a biphasic cell population. Acrospiromas are benign, and treatment consists of surgical excision.

A pigmented scalp nodule: malignant blue nevus

The malignant blue nevus is an aggressive dermal melanocytic neoplasm. The lesion occurs most frequently on the scalp of men in their fifth decade of life, often metastasizes to the regional lymph nodes, and commonly results in fatality. Controversy exists as to whether this lesion is a malignant melanoma in the dermis or a separate neoplasm arising in the architecture of a cellular blue nevus. The lesion is treated with wide local excision and close monitoring for the occurrence of metastatic disease.

Hepatitis C and porphyria cutanea tarda

Porphyria cutanea tarda (PCT) is a clinical manifestation of decreased uroporphyrinogen decarboxylase (UPD) activity. Multiple endogenous and exogenous factors have been implicated in inducing PCT in genetically predisposed patients. The most recent is the RNA virus hepatitis C (HCV), which is transmitted via blood exposure. The mechanism of action in HCV-induced PCT is unknown but produces the same clinical, laboratory, and histopathologic changes seen in other forms of sporadic PCT. Therefore, patients presenting with PCT clinically should be tested serologically for antibodies against HCV and patients with HCV should be monitored for signs and symptoms of PCT.

A man with nevoid hyperkeratosis of the areola

Nevoid hyperkeratosis of the nipple and areola is a unique clinical entity and a diagnosis of exclusion. The patient presenting with nipple/areolar hyperkeratosis must be examined carefully for other underlying cutaneous diseases such as epidermal nevi, ichthyosis, acanthosis nigricans, Darier's disease, cutaneous T-cell lymphoma, and other chronic skin dermatitides that may be responsible for the changes. If no other clinical findings are evident, the diagnosis can be made. Although the disorder is more common in women of childbearing age, men may show nevoid changes after estrogen therapy or idiopathically. The use of topical 12 percent lactic acid lotion (Lac-Hydrin) resolves the skin changes over a six-month period.

Differences in the nephrotoxicity of hydroquinone among Fischer 344 and Sprague-Dawley rats and B6C3F1 mice

The present studies indicate pronounced species-, sex-, and strain- related differences in the acute nephrotoxicity of hydroquinone (HQ) when administered by gavage to male and female Sprague-Dawley (SD) rats, Fischer 344 (F344) rats, and B6C3F1 mice. Following a single dose of 400 mg/kg, male and female F344 rats displayed pronounced enzymuria and glucosuria. In female F344 rats, urinary alkaline phosphatase and glucose were the most sensitive indicators of renal toxicity, reaching levels of, respectively, 157 times and 137 times control values within 24 h of dosing. HQ treatment of male F344 rats also resulted in significant enzymuria, although it was less marked than that seen in female F344 rats. Significant numbers of epithelial cells were also present in the urine from F344 rats at 200 (female) or 400 mg/kg (male and female). SD rats did not show evidence of elevated levels of urinary enzymes or increased blood urea nitrogen (BUN) after oral administration of HQ at a dose level of 400 mg/kg. Oral administration of HQ to male and female B6C3F1 mice at 350 mg/kg resulted in only slight but significant increases in BUN.

Human exposure to naturally occurring hydroquinone

Hydroquinone (HQ) is a nonvolatile chemical used in the photographic, rubber, chemical, and cosmetic industries. HQ is also known to occur in nature as the beta-D-glucopyranoside conjugate (arbutin), and free HQ is a known component of cigarette smoke. Low concentrations of HQ have been detected in the urine and plasma of humans with no occupational or other known exposure to HQ. The studies reported here investigate dietary and other potential sources of HQ and their contribution to HQ concentrations in the plasma and urine of human volunteers. Analysis of possible food sources of HQ by GC indicated significant amounts of arbutin in wheat products (1-10 ppm), pears (4-15 ppm), and coffee and tea (0.1 ppm). Free HQ was found in coffee (0.2 ppm), red wine (0.5 ppm), wheat cereals (0.2-0.4 ppm), and broccoli (0.1 ppm). After consuming a meal including arbutin- and HQ-containing foods, volunteers showed significant increases in plasma and urinary levels of HQ and its conjugated metabolites (total HQ). Mean plasma concentrations of total HQ peaked at 5 times background levels at 2 h after the completion of the meal, and mean urinary excretion rates of total HQ peaked at 12 times background at 2-3 h after the meal. Immediately after smoking four cigarettes in approximately 30 min, mean plasma concentrations of total HQ were maximally 1.5 times background levels; mean urinary excretion rates of total HQ peaked at 2.5 times background at 1-3 h after smoking. These data indicate that considerable human exposure to HQ can result from plant-derived dietary sources and, to a lesser extent, from cigarette smoke.

Analysis of studies related to tumorigenicity induced by hydroquinone

Hydroquinone (HQ) produced renal adenomas in male F344 rats, and these tumors appeared to arise from areas of spontaneous progressive nephropathy; the nephropathy itself has been found to be enhanced by HQ. Other neoplasms were not confirmed to be causally related to HQ among the reported bioassays. In the male F344 rat, HQ administered alone was not DNA reactive. HQ produced enhanced proliferation of renal tubular epithelium, presumably through toxicity involving glutathione conjugate formation. In the kidney, bone marrow, and other tissues, HQ may induce toxicity by redox cycling and lipid peroxidation. In bone marrow, HQ may produce microtubulin dysfunction, which is a plausible explanation for positive cytogenetic tests, the only consistently positive genotoxicity effect reported for HQ. Although HQ is a metabolic product of benzene, several lines of evidence suggest that the effects of HQ exposure are significantly different from those of benzene. Based upon the plausible mechanisms by which HQ may produce kidney tumors in male rats, we have concluded that occupational exposure levels of HQ are not predicted to be a cancer risk for humans.

Calcium overload during reperfusion is accelerated in isolated hypertrophied rat hearts

In this study, calcium overload during reperfusion and the severity of morphologically evident ischemic myocardial injury were compared in hypertrophied and normal hearts. Hypertrophied hearts isolated from rats where a clip had been placed on the proximal thoracic aorta for 6 weeks were compared to those from sham-operated rats in an isolated state perfused with Krebs-Henseleit buffer containing 3% albumin, 1.2 mM palmitate and 11 mM glucose. The isolated hearts were exposed to global, no-flow, normothermic ischemia following potassium arrest and were reperfused. Following ischemia and reperfusion, left ventricular end diastolic pressure was increased (39 +/- 7 v 13 +/- 2 mmHg, P < 0.05), and percentage recovery of left ventricular systolic function was decreased (34.4 +/- 8.9 v 77.1 +/- 6.3% P < 0.05), in hypertrophied hearts compared to control hearts. Calcium overload during reperfusion was two and one-half times greater in the hypertrophied hearts than in the control hearts and showed significant relationships with recovery of left ventricular systolic function (r = -0.86, P < 0.001) and left ventricular end diastolic pressure (r = 0.78, P < 0.005). Myocardial energy charge did not differ between the two groups at the end of reperfusion. Ischemic myocardial injury was quantitated morphologically by point counting techniques in a comparable series of control and hypertrophied hearts. After ischemia, hearts were either exposed to a monoclonal antimyosin antibody to identify and measure irreversibly injured myocardium by light microscopy or fixed by perfusion with 2.5% glutaraldehyde to quantitate the morphologic changes ultrastructurally. Control and hypertrophied hearts were not significantly different in severity of myocardial injury due to ischemia as assessed morphologically. Thus, the data suggest that calcium overload during reperfusion plays a significant role in post-ischemic left ventricular dysfunction of the hypertrophied heart. The accelerated calcium overload that occurs in the hypertrophied rat heart during reperfusion cannot be explained by differences in severity of myocardial injury during ischemia which indicates that other mechanisms are responsible.

Measurement of nuclear DNA modification by 32P-postlabeling in the kidneys of male and female Fischer 344 rats after multiple gavage doses of hydroquinone

Oral administration of hydroquinone (HQ) to male Fischer 344 (F344) rats results in dose-related kidney toxicity beginning with mild enzymuria by 1 week, significant cell proliferation by 6 weeks, and nephropathy and an increase in the incidence of renal tubule adenomas after 2 years. Female F344 rats, B6C3F1 mice, Sprague-Dawley rats, dogs, and humans are resistant to the renal toxicity of HQ associated with repeated exposure. To determine the potential of HQ to induce covalent DNA adducts in the kidney, male and female F344 rats were given 0, 2.5, 25, or 50 mg/kg HQ by gavage for 6 weeks, and nuclear DNA isolated from kidneys was analyzed by the 32P-postlabeling assay. At 50 mg/kg, males, but not females, showed an increase in the rate of excretion of N-acetyl-beta-D-glucosaminidase, indicative of proximal tubular damage. Analysis of nuclear DNA preparations by the postlabeling assay showed that HQ does not produce covalent DNA adducts in the kidneys of male and female rats. The assay's lower limit of detection is 1 adduct in 10(9) to 10(10) DNA nucleotides. No treatment-related increases in background radioactivity levels on the chromatograms were seen at locations corresponding to the major in vitro adducts of HQ and p-benzoquinone. HQ treatment, however, resulted in the reduction of the levels of certain endogenous adducts (I-compounds), the biological significance of which is unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of cell proliferation in the kidneys of Fischer 344 and Sprague-Dawley rats after gavage administration of hydroquinone

Oral administration of hydroquinone (HQ) over 2 years to male Fischer 344 (F344) rats results in a dose-related nephropathy and an increase in the incidence of renal tubule adenomas. Female F344 rats, B6C3F1 mice, and Sprague-Dawley (SD) rats are resistant to the chronic renal toxicity of HQ, and nephrotoxicity was not seen in dogs or humans following subchronic exposure. To better characterize the early development of renal toxicity in rats, cell proliferation was quantitated within the proximal (P1, P2, and P3) and distal tubule segments of the kidney in rats given 0, 2.5, 25, or 50 mg/kg HQ by gavage. Male and female F344 rats were treated for 1, 3, or 6 weeks, and male SD rats were treated for 6 weeks. Cell proliferation was quantitated by incorporation of bromodeoxyuridine, detected immunohistochemically, into newly synthesized DNA. At 6 weeks, renal cell proliferation was increased over vehicle-controls in male F344 rats dosed at 50 mg/kg. Significant elevations (p < 0.001) occurred in the P1 segments (87%) and in the P2 segments (50%) but the elevation in the P3 segment (34%) was not statistically significant. Urinalyses revealed increases in the rate of excretion of enzymes indicative of proximal tubular damage. Histopathologic evaluation of the kidneys was consistent with a dose-related tubular degeneration in the male F344 rat. No chemical-related effects were observed in the kidneys of female F344 and male SD rats. These data parallel the findings of sex- and strain-specific kidney adenomas in the 2-year bioassays, and suggest that chemically induced cell proliferation secondary to toxicity may be important in the pathogenesis of benign renal tumors in male F344 rats treated with HQ.

Dermatological manifestations in a tropical training environment: emphasis for the general medical officer

Cutaneous disease in the tropical training environment will be of concern for the medical officer assigned to ensure the health of soldiers participating in training. A review of all "sick calls" recorded during deployment to the Jungle Operations Training Center at Fort Sherman, Panama showed that 50% of the medical complaints were dermatologically related. This should emphasize the need for medical officers to have significant dermatologic knowledge and appropriate supplies.

The use of pharmacokinetics as an interpretive and predictive tool in chemical toxicology testing and risk assessment: a position paper on the appropriate use of pharmacokinetics in chemical toxicology

It has been recognized for several decades in the pharmaceutical industry that the safety evaluation of pharmacological agents must include pharmacokinetic (PK) studies, which are designed to determine the rate of absorption, distribution, metabolism, and excretion (ADME). In recent years the importance of such ADME studies in toxicology has also become increasingly apparent to the chemical industry. This increased focus has led to testing strategies that can produce ADME/PK data with greater applicability to toxicity testing and risk assessment. An example of such a strategy is the concept of a tiered approach to the conduct of ADME/PK studies (Wilson, A. G. E., Frantz, S. W., and Keifer, L. C. (1994). Environ. Health Perspect., in press). However, in practice, PK data are often viewed as being of limited usefulness and of only ancillary importance to the determination of chemical toxicity. As a consequence, the close integration of PK studies with toxicity-testing protocols is not always practiced within the chemical industry and is thus frequently scheduled independently from toxicity testing. This lack of integration has resulted in the design of subchronic (13-week) and chronic (2-year) toxicity studies without the benefit of PK information to establish the appropriate dose levels to be used, often because of inappropriate timing. The result is that much of the PK data which have been generated is without a clear consideration of its application to toxicity testing and risk assessment. This position paper is intended to provide recommendations for the appropriate design and interpretation of a PK study, as well as when and how to use PK data in the interpretation of toxicology data. Additional issues discussed in the paper include the design of PK studies to evaluate tissue time-course relationships and chemical persistence, the overall usefulness of PK data to toxicology testing, and the utility of PK as a useful interpretive and predictive tool in toxicology and risk assessment.

A two-generation reproduction study with hydroquinone in rats

The effects of hydroquinone (HQ) on reproductive performance and fertility were assessed in a two-generation study with CD Sprague-Dawley rats (one litter per generation). HQ was administered in an aqueous solution by gavage at doses of 0, 15, 50, and 150 mg/kg/day. F0 and F1 parental animals were dosed daily for at least 10 weeks prior to cohabitation, during cohabitation, and until scheduled termination. At all dose levels tested, no adverse effects were observed on feed consumption, survival, or reproductive parameters for the F0 or F1 parental animals. Mild, transient tremors were observed shortly after dosing at 150 mg/kg/day in several F0 and F1 parental animals and in a single F0 male at 50 mg/kg/day. These tremors occurred infrequently and were considered to be due to an acute stimulatory effect of HQ on the nervous system. Body weights for F0 and F1 parental females were similar between all dose groups throughout the study. Body weights for F0 parental males were also comparable to those of control throughout the study. Statistically significant differences in body weights were noted for the F1 parental males in the 50 and 150 mg/kg/day dose groups at several intervals during the premating, mating, and postmating periods. No treatment-related effects on pup weight, sex distribution, or survival were noted for pups of either generation. Upon postmortem examination, no treatment-related gross lesions were observed in either the F0 or F1 parental animals or their weanlings. Histopathologic examination of reproductive tissues and pituitary glands from high-dose F0 and F1 parental animals did not reveal any changes related to treatment with HQ.(ABSTRACT TRUNCATED AT 250 WORDS)

A study of developmental toxicity of hydroquinone in the rabbit

To obtain information on potential developmental toxicity, hydroquinone (HQ) was administered to pregnant New Zealand White rabbits (18 mated per dose group) in aqueous solution (0, 25, 75, or 150 mg HQ/kg/day) by gavage on Gestation Days (GD) 6 to 18. Caesarean sections were performed on GD 30. Doses of 75 and 150 mg/kg/day adversely affected feed consumption and/or body weights of dams during the treatment period. At these doses, however, treatment-related effects were not evident from physical observations, liver and kidney weights, premature delivery incidence, and caesarean sectioning data. The NOEL for maternal toxicity was 25 mg/kg/day. In the 150 mg/kg/day dose group, total incidences of external, visceral, and skeletal findings for fetuses did not differ statistically from controls. Slight, statistically insignificant, increases were found, however, in the incidences of ocular and minor skeletal malformations (micro-ophthalmia, vertebral/rib defects, angulated hyoid arch) on both a per fetus and a per litter basis. Under the conditions of this study, HQ at 150 mg/kg/day produced minimal developmental alterations in the presence of maternal toxicity. The NOEL for developmental toxicity was 75 mg/kg/day.