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Biomedical subjects

T E Knight

Publications and source records attributed to T E Knight.

12 recordsLinked to original sources
PubMed2003

Lead toxicosis in cats-a review.

Although the incidence of lead toxicosis in small animals continues to decrease, it remains a significant malady. We have reviewed the literature of the past 45 years, which revealed 70 cases involving cats. Sources, signs, diagnosis, pathology and treatment of feline lead toxicosis are reviewed. In 84% of these cases the source of lead was old paint usually from home renovation. The most common signs in cats are anorexia, vomiting, and seizures. The younger individuals seem more likely to show CNS signs. Since signs are often vague, lead toxicosis may be significantly under diagnosed in cats. The gold standard of diagnostic tests is blood lead concentration, although it does not necessarily correlate with total body burden of lead or with metabolic effects including clinical signs. Diagnostic tests including erythropoietic protoporphyrin (EPP), urine aminolevulinic acid, and others are discussed. Gross findings on necropsy are few and include a yellow-brown discoloration of the liver often with a nutmeg-like appearance. Histological examination may reveal pathognomonic inclusion bodies in liver and renal tissues. Characteristic histological changes in the CNS include neuronal necrosis and demyelination. Treatment of lead toxicosis in cats, as in any species, involves removing the exposure, decontaminating the individual and the environment, supportive care and chelation therapy. The most recently available chelator is succimer (meso 2,3-dimercaptosuccinic acid). Succimer given orally is well tolerated and has a wide margin of safety. A high index of suspicion of lead toxicosis is warranted in cats since they often present with vague and non-specific signs. With any consistent history owners need to be asked about home renovation. Early diagnosis and treatment affords a good prognosis.

Animals↗
PubMed2001

Succimer for treatment of lead toxicosis in two cats.

Two cats from a single household were examined because of neurologic abnormalities suggestive of central vestibular disease. The owner had been renovating her 150-year-old house for the preceding 3 months, and renovations included chipping and sanding of old paint from windowsills and stair railings. Lead toxicosis was diagnosed on the basis of history and concentrations of lead in blood and urine. Both cats were treated with succimer. Treatment was not associated with any adverse effects, and both cats recovered completely. Ingestion of old paint from house renovations is the most common source of lead exposure in cats. Owners of cats with gastrointestinal tract or neurologic abnormalities should be questioned specifically about house renovations.

Animals↗
PubMed1997

Thespesia populnea dermatitis.

BACKGROUND: The allergenic properties of milo wood have not been known before now. OBJECTIVE: We investigated the wood and elucidated the structure of its main sensitizer. METHODS: A bowl turner suffered from allergic contact dermatitis over years. Wood shavings were extracted, and the constituents were isolated, purified, and identified. The sensitizing capacity of the main compound was determined experimentally in guinea pigs. RESULTS: Initially, patch tests with sawdust suspensions and the isolated main constituent were positive. During the course of the study, however, the patient developed tolerance. The main component of milo wood was identified as a new mansonone: 7-hydroxy-2,3,5,6-tetrahydro-3,6, 9-trimethylnaphtho [1,8 bc] pyran-4,8-dione. In the sensitizing experiments, it showed to be a moderate sensitizer. CONCLUSION: Extensive and long-lasting exposure to certain sensitizers may cause the phenomenon of hardening as has been shown in the wood working industry.

Adult↗
PubMed1996

Giant polypoid basal cell carcinoma.

Basal cell carcinomas may attain giant proportions due primarily to recurrence and neglect. Giant basal cell carcinomas (5 cm or more in diameter) are of four clinical subtypes: noduloulcerative, morpheaform, superficial, and polypoid. We report a patient with a typical polypoid lesion of fifteen years' duration on his shoulder. The polypoid variant differs from other giant basal cell carcinomas in several important ways: the polypoid lesions appear on the torso or extremity, rather than the head or neck, as beefy-red, friable, exophytic masses for which the patient typically has had no previous treatment; the histologic type tends to be nonaggressive; and finally, the lesions are amenable to surgical cure with low metastatic potential.

Adult↗
PubMed1996

Resorcinols and catechols: a clinical study of cross-sensitivity.

BACKGROUND: All allergic contact dermatitis caused by Philodendron species is common in the Hawaiian islands, and Toxicodendron species are the most common causes of plant-induced allergic contact dermatitis in North America. OBJECTIVE: The purpose of this study was to determine the incidence of cross-sensitivity between these plant species. METHODS: Alkylresorcinols (pentadec[en]yl and heptadec[en]ylresorcinols) were isolated and purified from extracts of Hawaiian-grown Philodendron scandens subspecies scandens and Philodendron lacerum. Alkylcatechols (mixtures of pentadec[en]ylcatechols from an extract of Toxicodendron radicans (poison ivy) were obtained from the Division of Biologics Standards (National Institutes of Health, Bethesda, MD). Seventeen patients from Hawaii and 8 patients from northern California were skin tested with 5 microL (concentrations, 1 to .001 mg/mL) of each allergen applied to the flexor forearm. The test sites remained open and were graded at 72, 96, and 144 hours. All 8 patients from California were naive to Philodendron species, and 8 patients from Hawaii were naive to Toxicodendron species. RESULTS: No cross-reactivity occurred in patients who were Philodendron sensitive and Toxicodendron naive when tested to the homologous Toxicodendron catechols. Conversely, with one exception, no cross-reactivity occurred in patients who were Toxicodendron sensitive and Philodendron naive when tested to homologous Philodendron naive when tested to homologous Philodendron resorcinols. CONCLUSION: Patients who are sensitive to Philodendron species (or other resorcinol-containing plants) may not necessarily be cross-sensitive to Toxicodendron species and vice versa.

Adolescent↗
PubMed1994

Melaleuca oil (tea tree oil) dermatitis.

BACKGROUND: Melaleuca oil (tea tree oil) is the essential oil distilled from the leaves of Melaleuca alternifolia Cheel. Tea tree oil is popular for treating various cutaneous maladies. OBJECTIVE: Our purpose was to determine which constituent compounds of Melaleuca oil are responsible for allergic contact eczema in seven patients who became sensitized. METHODS: The seven patients were patch tested with Finn Chambers to a 1% solution (vol/vol) of melaleuca oil and 1% solutions (vol/vol) of 11 constituent compounds. RESULTS: Of seven patients reactive to the 1% melaleuca oil solution, six patients also reacted to limonene, five to alpha-terpinene and aromadendrene, 2 to terpinen-4-ol, and one each to p-cymene and alpha-phellandrene. d-Carvone, an autooxidative derivative of limonene, caused no reactions among the seven patients. CONCLUSION: d-Limonene was the most common allergen causing allergic contact eczema in our patients. Clinicians are likely to see more contact eczema caused by the increasing use of this popular nostrum.

Aged↗
PubMed1994

Solar (brachioradial) pruritus--response to capsaicin cream.

BACKGROUND: Solar (brachioradial) pruritus is an enigmatic condition affecting the lateral aspects of the arm(s) and is primarily seen in Caucasian people living in the tropics or subtropics. METHODS: Over a 5-year period we prospectively evaluated 68 patients with solar pruritus seen in an outpatient dermatology clinic. Clinical, biochemical, and microscopic and ultramicroscopic studies were performed. An open-label trial of capsaicin cream application was initiated in 15 patients. RESULTS: An almost equal number of men and women were seen with an average age of 44 years. Brown-eyed and blue-eyed patients were seen with equal frequency. Most patients (86%) had outdoor occupations or avocations. The pruritus was intense, usually bilateral (72%) and invariably affected the lateral (as opposed to medial) aspects of the arm(s) in the absence of primary lesions. The most commonly affected area was the elbow area superficial to the brachioradialis and extensor carpi longus muscles, but extension of the pruritus to include the forearm and/or upper arm was common. Biopsy specimens (stained with hematoxylin and eosin) were normal or showed mild actinic elastosis in 15 patients tested. Ultramicroscopy showed myelin sheath splitting in all four patients studied. This is a nonspecific finding that may also be found in diabetic or alcoholic neuropathy. Ten of thirteen patients completing the capsaicin-cream study found significant relief (itching much improved or gone) after 3 weeks compared with the untreated control arm. CONCLUSIONS: The cause of solar pruritus remains unknown, but circumstantial evidence implicates chronic exposure to solar radiation. Capsaicin may offer relief to these patients, but the patients need to be cautioned about the burning sensation that occurs with capsaicin cream.

Administration, Cutaneous↗
PubMed1992

Hepatocellular carcinoma invasive to chest wall.

An 88-year-old white man developed hepatocellular carcinoma forming a large subcutaneous mass by direct invasion of the posterior chest wall. Forty-seven cases of cutaneous metastases from primary liver cancer have been reported. These cutaneous metastases showed protean morphologic features with the face and scalp being the most common sites of involvement. The metastatic lesions may be the presenting sign of the cancer. Average survival, after development of a skin metastasis, was 5 months. Skin metastases from primary liver cancer are being reported more frequently. This is due, in part, to more prolonged survival of liver cancer patients, which allows development of skin metastases, and also due to increased awareness by the clinician.

Aged↗
PubMed1991

Ketoconazole-induced fulminant hepatitis necessitating liver transplantation.

The most serious side effect of ketoconazole is hepatitis, which has proved fatal in seven reported cases. We present a case of fulminant hepatic failure in a 45-year-old Oriental woman that probably would have been fatal except for a successful liver transplant. A review of the literature of fatalities associated with ketoconazole is presented.

Candidiasis↗
PubMed1991

Philodendron-induced dermatitis: report of cases and review of the literature.

Plants of the genus Philodendron, and the family Araceae, were reported as causing dermatitis as early as 1923. The allergenic compounds in philodendrons are resorcinols, which share common chemical side chains with the allergenic catechols of Toxicodendron members of the family Anacardiaceae. I report here two cases of allergic contact dermatitis to Philodendron species commonly found in the Hawaiian islands. Philodendron dermatitis, however, is not confined to tropical or subtropical areas. Exposure may occur in nursery workers in temperate climates and in the home environment worldwide.

Acute Disease↗
PubMed1980

Angiosarcoma (angioendothelioma) of the scalp. An unusual case of scarring alopecia.

Angiosarcoma with initial involvement of the scalp is a rare, malignant neoplasm. We present the case of a 77-year-old woman in whom extensive scarring alopecia developed that was proved histologically to be due to angiosarcoma. She had a good initial response to treatment with electron-beam therapy, but after seven months, extensive nodules and indurated areas on the face beyond the borders of the radiation field developed. Subsequently, massive cervical adenopathy and metastases to the lungs, liver, and spleen developed. Angiosarcoma must be differentiated from other malignant blood vessel tumors and should be considered in the differential diagnosis of scarring alopecia of the scalp in elderly patients.

Aged↗