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Biomedical subjects

J M Jackson

Publications and source records attributed to J M Jackson.

At least 19 recordsLinked to original sources
PubMed2000

Clinical features and treatment of peristomal pyoderma gangrenosum.

CONTEXT: Peristomal pyoderma gangrenosum (PPG), an unusual variant of pyoderma gangrenosum, has been reported almost exclusively in patients with inflammatory bowel disease (IBD) and is frequently misdiagnosed. OBJECTIVE: To better characterize the clinical manifestations, diagnosis, and management of PPG. DESIGN, SETTING, AND PATIENTS: Retrospective analysis of 7 patients with PPG observed in a university-affiliated community setting between 1988 and December 1999. MAIN OUTCOME MEASURES: Clinical and histopathologic features, associated disorders, and microbiologic findings. RESULTS: Two patients had Crohn disease, 2 had ulcerative colitis, and 3 had abdominal cancer. Five patients had at least 1 relapse of PPG after initial healing. Although 3 of 4 patients with IBD had active bowel disease, a parallel course with PPG occurred in only 1 patient. Both patients whose stoma was relocated developed an ulcer at the new site. Effective therapies included topical superpotent corticosteroids; intralesional injection of triamcinolone acetonide at the ulcer margin; topical cromolyn sodium; oral dapsone, prednisone, cyclosporine, mycophenolate mofetil; and intravenous infliximab. CONCLUSION: Our experiences demonstrate that although PPG has been most often reported in patients with IBD, it may occur in the absence of IBD. Biopsy of the skin lesion is not diagnostic but excludes other causes. Relocation of the stoma may be associated with a new ulceration and should be avoided. Trauma to the skin of a predisposed patient may elicit the pustules or ulcerations associated with pathergy. JAMA. 2000;284:1546-1548.

Adult↗
PubMed2000

Pyoderma gangrenosum. A comparison of typical and atypical forms with an emphasis on time to remission. Case review of 86 patients from 2 institutions.

Pyoderma gangrenosum (PG) is an idiopathic, inflammatory, ulcerative disease of undetermined cause. The diagnosis is based on clinical and pathologic features and requires exclusion of conditions that produce ulcerations. An atypical bullous variant (atypical pyoderma gangrenosum, APG) exists with clinical features similar to those of Sweet syndrome. Because PG is a rare disease, few large case series have been reported. Pyoderma gangrenosum was first recognized as a unique disease entity in the first half of the 20th century. Cumulative knowledge of PG is based on a handful of case series and multiple individual case reports. To augment that knowledge, we present our experience with a large number of patients over a significant time. We performed a retrospective analysis of the medical records of 86 patients with PG who were evaluated and treated over 12 years at 2 university-based dermatology departments. The mean (+/- standard deviation) age of onset of PG and APG, respectively, was 44.6 +/- 19.7 years and 52.2 +/- 15.3 years. Lower extremity involvement was most common in PG, whereas upper extremity involvement was most common in APG. Associated relevant systemic diseases were seen in 50% of patients. Inflammatory bowel disease was the most common association in patients with PG, whereas hematologic disease or malignancy was most common in those with APG. Although a few patients were managed with local measures or nonimmunosuppressive treatment, the majority required oral corticosteroid therapy, often with systemic immunosuppressive treatment. PG patients required a mean 11.5 +/- 11.1 months of treatment to achieve remission compared with 9.0 +/- 13.7 months for patients with APG. Five patients (5.8%) had disease that was extremely refractory to multiple intensive therapies. The prognosis and disease associations for PG and APG appear to be different. Compared with PG, APG is more often associated with hematologic disease or malignancy, and remits more quickly.

Adolescent↗
PubMed1998

Morning vs evening light treatment of patients with winter depression.

BACKGROUND: According to the phase-shift hypothesis for winter depression, morning light (which causes a circadian phase advance) should be more antidepressant than evening light (which causes a delay). Although no studies have shown evening light to be more antidepressant than morning light, investigations have shown either no difference or morning light to be superior. The present study assesses these light-exposure schedules in both crossover and parallel-group comparisons. METHODS: Fifty-one patients and 49 matched controls were studied for 6 weeks. After a prebaseline assessment and a light/dark and sleep/wake adaptation baseline week, subjects were exposed to bright light at either 6 to 8 AM or 7 to 9 PM for 2 weeks. After a week of withdrawal from light treatment, they were crossed over to the other light schedule. Dim-light melatonin onsets were obtained 7 times during the study to assess circadian phase position. RESULTS: Morning light phase-advanced the dim-light melatonin onset and was more antidepressant than evening light, which phase-delayed it. These findings were statistically significant for both crossover and parallel-group comparisons. Dim-light melatonin onsets were generally delayed in the patients compared with the controls. CONCLUSIONS: These results should help establish the importance of circadian (morning or evening) time of light exposure in the treatment of winter depression. We recommend that bright-light exposure be scheduled immediately on awakening in the treatment of most patients with seasonal affective disorder.

Adult↗
PubMed1998

Scarring alopecia and sclerodermatous changes of the scalp in a patient with hepatitis C infection.

Hepatitis C virus (HCV) is a common cause of chronic hepatitis and is frequently associated with extrahepatic disease. Recently, cutaneous disorders have been a presenting manifestation of HCV infection. Porphyria cutanea tarda (PCT) is one of the cutaneous diseases associated with hepatitis C. PCT manifests in an acute form with tense bullae and erosions and in a chronic form with milia, scarring, and sclerodermatous changes. HCV has also been implicated as a cause of vasculitis through immune complex deposition. We report a patient in whom HCV was associated with sclerodermoid PCT and a medium vessel vasculitis. This case underscores the importance of HCV and its potential cutaneous manifestations, as well as the importance of recognizing cutaneous manifestations of internal disease that may be the first clue to diagnosis of HCV.

Aged↗
PubMed1998

Methyldibromoglutaronitrile (Euxyl K400): a new and important sensitizer in the United States?

BACKGROUND: Methyldibromoglutaronitrile (MDGN) is a component of Euxyl K400, a preservative used in many skin care products in Europe. MDGN has been used in skin care products in the United States for the last 5 years. Contact allergy from MDGN has been reported from Europe. OBJECTIVE: The purpose of this study was to determine the frequency of MDGN as a sensitizer in patients undergoing routine patch testing. METHODS: We reviewed the results in 163 patients who underwent patch testing during a 4-month period to determine the number who had any reaction to MDGN at two different concentrations (0.2% and 0.5%). Tests were graded with the use of the North American Contact Dermatitis Group criteria (0 to 3+), and readings were performed at 48 and 96 hours (all positive reactions were evaluated at a follow-up visit or by telephone interview). RESULTS: In the 4-month period, 45 of the 163 patients showed some reaction (+/- to 3+) at one or more readings. Of these, the results for 23 patients were considered to be irritant false-positive reactions; for 3 patients, the results were classified as uncertain; and for 19 patients, the results were classified as allergic. Of these, the results for eight patients were of definite relevance; the results for five patients were of probable relevance, and the results for six patients were of doubtful relevance to the problem condition. Other positive patch tests to a variety of allergens were frequently seen in persons positive to MDGN. CONCLUSION: MDGN is a sensitizer in skin products and, with the increase of its use, should be considered in the patch test evaluation of patients with persistent dermatitis. Optimum patch test concentrations are yet to be determined.

Allergens↗
PubMed1998

Early- and late-stage breast cancer in a managed care setting in relation to mammography screening.

A case-control study was conducted to ascertain occurrence of advanced- and early-stage breast cancer, use of mammography, and the relationship between the two. All women with stage III/IV breast cancer (N = 46) were matched to two controls (stage 0/I and stage II) by year of diagnosis and age. Matched-pair analyses assessed antecedent use of screening mammography. Results indicated that advanced-stage patients were significantly less likely than their stage 0/I counterparts to have had antecedent screening within 13 months of diagnosis [chi2: 5.78; OR: 6.0; p < 0.05]. Cases compared with stage II controls did not differ statistically. Efforts should focus on increasing mammography in currently targeted age groups. Considerations might be toward extending regular screening for women 40 to 49 and over 75.

Adult↗
PubMed1996

L-carnitine and acetyl-L-carnitine status during hemodialysis with acetate in humans: a kinetic analysis.

The effects of the acetate content of hemodialysis fluids on the relation between L-carnitine (free carnitine, cr FC) and acetyl-L-carnitine (AC) have not previously been examined in detail. The net fluxes of FC, AC, and acetate between intra- and extracellular pools during hemodialysis were calculated using a kinetic model with dialysates containing three concentrations of FC (0, 40, and 80 mumol/L) and either 40 or 3 mmol acetate/L. Radioenzymatic assays of FC and AC were optimized for use with samples taken during hemodialysis. Acetate stimulated a tissue uptake of FC (P < 0.05) that could exceed the rate of FC delivery and was related to the dialysate FC composition (P < 0.02). There were associated changes in tissue AC output. With dialysate containing 40 mmol acetate/L, AC tissue output was directly related to the dialysate FC composition (P < 0.05). The AC tissue output was less with dialysate containing 3 mmol acetate/L (P < 0.05) but the significant increase with the provision of FC in the dialysate was retained (P < 0.05). Hemodialysis may therefore represent an acute period of relative carnitine deficiency when regeneration of free coenzyme A from acetyl coenzyme A consequent to metabolism of acetate is limited.

Acetates↗
PubMed1995

Plasma non-esterified fatty acid response to dialysate acetate concentration during haemodialysis in humans.

We have inhibited the in vitro generation of non-esterified fatty acids in plasma samples taken during haemodialysis by cooling the samples rapidly, centrifuging and freezing within 5 min of sampling and completing the assay on the same day. The relationship of non-esterified fatty acid concentrations during haemodialysis to the acetate concentration of the dialysate and the profile of circulating lipase activities was studied. With this sample-handling protocol we found lower non-esterified fatty acid concentrations than reported in many other studies and the results suggest that, under normal conditions of haemodialysis, the circulating non-esterified fatty acid concentrations and the associated risk of unwanted side-effects may have been previously over-estimated due to artefactual in vitro sample lipolysis. We also showed that, at the end of dialysis, when circulating lipase activities were least, the non-esterified fatty acid concentrations were lower (P < 0.05) with an acetate dialysate containing 37 mmol/l acetate than with a bicarbonate dialysate containing 3 mmol/l acetate.

Acetates↗
PubMed1995

Distance and pairing effects on the brownDominant heterochromatic element in Drosophila.

We examined the behavior of the brownDominant (bwD) heterochromatic insertion moved to different locations relative to centric heterochromatin. Effects were measured as the degree of silencing of a wild-type brown eye pigment gene by bwD across a tandem duplication. A series of X-ray-induced effects were recovered at high frequency. Cis-acting enhancers were obtained by relocation of the duplication closer to autosomal heterochromatin. Enhancers were also recovered on the homologous chromosome when it was similarly rearranged, revealing a novel interhomologue effect whereby interactions occur between genetic elements near opposite ends of a chromosome arm rather than between paired alleles. Cis-acting suppressors were obtained as secondary rearrangements in which the duplication was moved farther away from heterochromatin. Suppression was correlated with loss of cytological association between bwD and the polytene chromocenter. Surprisingly, the distance from bwD to the chromocenter was not correlated with the strength of enhancement or suppression. We propose that bwD fails to coalesce with the chromocenter when its position along the chromosome places it beyond a threshold distance from heterochromatin, and this threshold depends upon the configuration of both the chromosome carrying bwD and its paired homologue.

Alleles↗
PubMed1994

Immunophenotyping of childhood acute lymphoblastic leukemia in Saudi Arabia: second look.

Geographical variations in the incidence of disease are of considerable theoretical and practical importance. It has been claimed that the distribution of acute lymphoblastic leukemia (ALL) phenotypes in Saudi Arabia is different from that recorded in the Western literature. One hundred and twelve (112) patients under 15 years of age, diagnosed as ALL between January 1992 and May 1994 had immunophenotypes performed on their blast cells. Common ALL (cALL) together with pre-B-ALL, formed 86.5% of the total; B-cell 3%, T-cell 6% and null cell 4.5%. These figures are not significantly different from the Western literature. A previous claim from this institution in 1990, that both null and B-cell ALL were significantly increased compared with elsewhere, is not supported by the present figures. Age and sex distribution, and FAB classification, L1 77%, L2 20% and L3 3%, were also of the same order as described elsewhere and, in particular, there was no increase in the frequency of L3 subtype.

Adolescent↗
PubMed1993

CEO address.

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Costs and Cost Analysis↗
PubMed1992

Melatonin shifts human circadian rhythms according to a phase-response curve.

A physiological dose of orally administered melatonin shifts circadian rhythms in humans according to a phase-response curve (PRC) that is nearly opposite in phase with the PRCs for light exposure: melatonin delays circadian rhythms when administered in the morning and advances them when administered in the afternoon or early evening. The human melatonin PRC provides critical information for using melatonin to treat circadian phase sleep and mood disorders, as well as maladaptation to shift work and transmeridional air travel. The human melatonin PRC also provides the strongest evidence to date for a function of endogenous melatonin and its suppression by light in augmenting entrainment of circadian rhythms by the light-dark cycle.

Adult↗