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Biomedical subjects

J F Walter

Publications and source records attributed to J F Walter.

At least 19 recordsLinked to original sources
PubMed1990

B-mode ultrasound scanning in the detection of proximal venous thrombosis after total hip replacement.

A prospective study of the accuracy of real-time B-mode ultrasonography in detecting deep venous thrombosis in the femoral and popliteal veins of the lower extremity was conducted on a consecutive series of patients who had had a total hip replacement. Ascending venography was used as a diagnostic standard. One hundred and forty-three patients had ultrasound studies of both lower extremities and a venographic study of the operatively treated lower extremity at an average of 7.6 days postoperatively. The two tests were done within twenty-four hours of each other. Both ultrasonography and venography were done on 152 extremities. Two paired studies were excluded from the analysis of results because the ultrasound scans could not be interpreted. In 131 extremities, both diagnostic tests were negative for proximal thrombosis. Eight extremities had isolated thrombosis of a vein in the calf that was detected only by venography. In nineteen extremities, old or fresh thrombosis was diagnosed by venography. In four extremities, an old thrombosis of the superficial femoral vein was detected by both studies. In four of the extremities that had a new thrombus in the common femoral vein and in nine that had a new thrombus in the superficial femoral vein, abnormal findings on ultrasound scans correlated with those on venograms. There were two false-negative ultrasound scans and one false-negative venogram. The sensitivity, specificity, and accuracy of ultrasonography were 89, 100, and 99 per cent for the diagnosis of thrombosis of the proximal veins of the lower limb and 63, 100, and 93 per cent for the diagnosis of thrombosis when the entire venous system of the limb was included.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Diffuse arterial narrowing as a result of intimal proliferation: a delayed complication of embolectomy with the Fogarty balloon catheter.

Most complications of embolectomy with the Fogarty balloon catheter are recognized early and have received ample attention in the surgical and radiologic literature. However, the delayed complication of diffuse arterial narrowing causing severe ischemia has received little emphasis, perhaps because follow-up arteriography is not always performed. This report describes five patients--women 43 to 62 years of age--with progressive leg ischemia discovered 2 to 4 months after embolectomy with the balloon catheter. Angiography showed a characteristic pattern of severe, smooth narrowing of that portion of the artery in which balloon embolectomy was performed. Pathologic examination of arterial specimens, available in two of the five patients, revealed marked intimal cellular proliferation, which narrowed the arteries severely without evidence of thrombosis, significant atheromatosis, or active arteritis. The cause appears to be intimal damage by the balloon. Embolectomy with the balloon catheter should be done especially carefully in relatively young women.

Adult↗
PubMed1984

Therapeutic embolization of the small-bowel arteries.

Two patients with small-bowel arteriovenous malformations and four patients with severe small-bowel hemorrhage were successfully treated with selective embolization of jejunal or ileal arteries. No infarction of the embolized area was observed. Severe small-bowel bleeding frequently occurs in debilitated patients with multisystem failure. In these circumstances, the use of embolization is justified because of the need for fast and effective hemostasis if a trial of vasoconstrictor infusion has been ineffective or is contraindicated.

Arteriovenous Malformations↗
PubMed1984

Angiography of omental mesothelioma.

Angiographic features of three cases of omental mesothelioma are presented. These lesions appeared mildly or moderately hypervascular without arteriovenous shunting or arterial encasement. The predominant feeding arteries were the right and left gastroepiploics. Since arteriography may be performed in the evaluation of the often nonspecific presenting symptoms of patients with abdominal mesothelioma, radiologists should be aware of these abnormalities.

Abdominal Neoplasms↗
PubMed1984

Amiodarone photosensitivity.

Amiodarone hydrochloride is currently being investigated in the United States as a cardiac antiarrhythmic agent. Previous reports from Europe indicate that amiodarone occasionally causes a cutaneous photosensitivity reaction that may be associated with a peculiar blue-gray discoloration of the skin. In addition, corneal microdeposits of yellow-brown granules may occur. We report observations on a case of amiodarone photosensitivity and corneal deposits developing in a patient shortly after amiodarone therapy was begun. Symptoms included burning and stinging of the skin, with redness and swelling that developed immediately after sun exposure. Phototesting showed that the photoactivating wavelengths were primarily in the long-wave UV-A spectrum between 350 and 380 nm. Prior application of a 10% dioxybenzone sunscreen greatly reduced the phototest reaction. Four weeks after the patient stopped taking amiodarone, the UV-A sensitivity was still present but diminished, and by ten weeks it had disappeared. During this time, the corneal deposits were reduced in number. All ten patients we have treated so far with amiodarone for cardiac arrhythmias have shown a similar photosensitivity, indicating that this is probably a phototoxic reaction.

Aged↗
PubMed1983

Psoralen-containing sunscreen is tumorigenic in hairless mice.

Sunscreens containing 5-methoxypsoralen (5-MOP) are currently being marketed to promote tanning by inducing psoralen-mediated ultraviolet (UV) A (320-400 nm) melanogenesis. The rationale is that this may prevent UVB (290-320 nm) radiation-induced skin damage. However, mouse studies have shown that 5-MOP has the same cutaneous photocarcinogenic potential as 8-methoxypsoralen. In addition, the 5-MOP--containing sunscreen Sun System III (SS III), when combined with UVA, induces epidermal ornithine decarboxylase activity, an enzyme associated with tumor promotion. Therefore, we investigated whether SS III had sufficient psoralen concentration to be tumorigenic in hairless mice exposed to chronic, intermittent UVA radiation. SS III was applied to hairless mice 5 days per week for 20 weeks. After each application the mice were exposed to 2.5 to 10 joules/cm2 UVA radiation. All test groups developed atypical squamous papillomas in direct proportion to the dosage of UVA radiation received. A shorter latency period for tumor development was seen with larger UVA doses. Test animals followed up to 1 year developed invasive squamous cell tumors. Control groups (SS III without UVA and UVA without SS III) remained free of tumors. Animals receiving SS III plus UVA developed persistent skin thickening and increased dermal cyst formation similar to that reported with chronic exposure to UVB, a known carcinogenic wavelength. Over-the-counter sunscreens containing 5-MOP do contain sufficient psoralen concentrations to cause cutaneous phototoxicity and photocarcinogenicity in mice, and their use in humans should be discouraged in the interest of preventing further UV-induced skin damage and skin cancer.

5-Methoxypsoralen↗
PubMed1983

Changes in arachidonic acid metabolism in UV-irradiated hairless mouse skin.

This study was conducted to investigate the metabolism of arachidonic acid in the skin of hairless mice exposed to UVA, PUVA, UVB, and UVC irradiation. The main products of arachidonic acid in the epidermis were hydroxyeicosatetraenoic acid (HETE), PGE2, and PGD2. Dermis displayed a lower lipoxygenase activity (expressed as HETE production) than the epidermis and showed no detectable cyclooxygenase activity, i.e., no prostaglandin production. The main changes observed in UV-induced inflammatory reactions were as follows. 1. A 5-fold increase in dermal HETE production in PUVA-treated animals and a 29% reduction in epidermal HETE formation after UVC treatment. 2. A marked decrease of PGD2 and a marked increase of PGE2 formation due to alterations of PGH2 metabolism in the UVB-treated group; however, cyclooxygenase activity was unchanged. These changes in arachidonic acid metabolism in the skin may be of pathophysiologic importance in UV-induced inflammatory reaction.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1983

Gas in embolized tumors: an alternate hypothesis for its origin.

Gas within embolized, uninfected tumors has been ascribed to either carbon dioxide produced through anaerobic reticulocyte metabolism or oxygen release from oxyhemoglobin. An alternative hypothesis explaining the presence of gas within embolized, uninfected tumors, namely, that gas is introduced during the embolization procedure, is presented. Experimental results corroborating this hypothesis are also described.

Adenocarcinoma↗
PubMed1982

Psoralen-containing sunscreen induces phototoxicity and epidermal ornithine decarboxylase activity.

Sunscreens containing 5-methoxypsoralen (5-MOP) are being promoted commercially to increase suntanning and sun protection. A recent study indicated that the 5-MOP concentration used in these sunscreens is too low to induce cutaneous phototoxicity with ultraviolet (UV) radiation. We investigated whether the sunscreen Sun System III (SS III), which contains 5-MOP, could induce skin erythema, edema, delayed pigmentation, and epidermal ornithine decarboxylase (ODC) activity when used in conjunction with UVA radiation (320-400 nm). ODC induction is an early event in the promotion of skin tumors. Increased epidermal ODC activity has been reported after exposure to UVB radiation (290-320 nm) alone and with topical 8-methoxypsoralen (8-MOP) plus UVA radiation. Using a solar simulator, we found SS III-induced erythema, edema, and epidermal ODC activity in hairless mouse skin with only 5 joules/cm2 of UVA. Human skin showed erythema and delayed pigmentation with SS III plus 20 joules/cm2 of UVA. No phototoxicity was seen in human skin unless the solar simulator output was filtered through water to reduce infrared radiation. This indicates that cutaneous phototoxic reactions to 5-MOP plus UVA are diminished by heat. Like 8-MOP, 5-MOP cross-links DNA and has the same skin photocarcinogenic potential as 8-MOP. Therefore the use of phototoxic psoralens in over-the-counter sunscreens is inappropriate because of the risk of increased UV-induced skin cancer.

5-Methoxypsoralen↗
PubMed1981

Evaluation of seven sunscreens on hairless mouse skin.

The ability of seven sunscreens to protect against ultraviolet (UV)--induced inhibition of epidermal DNA synthesis was evaluated in vivo using a hairless mouse model. There were statistically significant differences among sunscreens in their ability to prevent UV-B (290 to 320 nm) inhibition of DNA synthesis. The protective factor (PF) of a sunscreen was arbitrarily defined as the ratio of the dose required to inhibit DNA synthesis by 50% with and without a sunscreen. The following PF values were determined: Coppertone 4, 4.4; Sundown Extra Protection, 8.4; Supershade 15, 21.0; Eclipse 15, 22.2; Blockout 15, 22.4; and Bain de Soleil 15, 27.6. Zinc oxide ointment protected against any significant suppression of DNA synthesis at all UV-B doses used. There was a relatively good correlation between the PF and the sun protection factor (SPF) claimed for each sunscreen by the manufacturer. However, the PF values determined in mouse skin were generally higher than the SPF values measured in human skin. Further studies are needed to determine if sunscreen substantivity (resistance to removal by water) can be evaluated by this technique.

Animals↗
PubMed1981

Calcified aortic plug syndrome.

Five women are described with an extremely rare manifestation of atherosclerosis. All presented with upper extremity hypertension and diminished femoral pulses. Three had intermittent claudication. Plain radiography and arteriography demonstrated focal, heavily calcified, mass-like, obstructing lesions that caused a functional coarctation of the aorta. These lesions involved both the thoracic and abdominal aorta. Three patients had visceral artery involvement. Atherosclerosis was diagnosed in the four patients who underwent endarterectomy or bypass surgery.

Adult↗
PubMed1980

Epidermal DNA synthesis: a new disc technique for evaluating incorporation of tritiated thymidine.

We present a new technique for evaluating epidermal DNA synthesis as measured by incorporation of tritiated thymidine. Standard areas of epidermis were isolated by glueing plastic discs to the skin followed by heating on a hot plate at 60 degrees C. The discs were then cut out and the dermis gently separated and removed by incubation at 60 degrees C in 2 M potassium bromide. The discs with attached epidermis were washed in 0.25% acetic acid to remove unincorporated tritiated thymidine and then counted in a liquid scintillation counter. Results were expressed as disintegrations per minute per disc. This technique showed good correlation to the hydroxylapatite column and perchloric acid methods for extracting DNA, but was considerably less tedious and subject to fewer errors. Incubation of discs in DNAse indicated radioactivity was primarily in DNA. The disc technique is simple, rapid and inexpensive and could be performed in large numbers even in unsophisticated laboratories.

Animals↗
PubMed1980

Double-blind comparison of topical 1 percent clindamycin phosphate (Cleocin T) and oral tetracycline 500 mg/day in the treatment of acne vulgaris.

An eight week double-blind study comparing 1 percent clindamycin phosphate (Cleocin T) applied topically with tetracycline 500 mg a day taken orally was conducted in fifty subjects. Topically applied 1 percent clindamycin phosphate was found to be superior to oral tetracycline at six weeks as judged by patient evaluation and reduction of papules. There was a consistent trend favoring clindamycin phosphate at the other visits but the difference was not significant. The use of topically applied 1 percent clindamycin phosphate seems to be a logical alternative to the use of oral tetracycline.

Acne Vulgaris↗