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Biomedical subjects

M Tharp

Publications and source records attributed to M Tharp.

11 recordsLinked to original sources

Recalcitrant molluscum contagiosum in an HIV-afflicted male treated successfully with topical imiquimod.

Molluscum contagiosum is a common cutaneous infection complicating the course of patients afflicted with acquired immunodeficiency syndrome. We describe a human immunodeficiency virus-positive patient with a disfiguring molluscum contagiosum infection of the face. Conventional cytodestructive therapies failed in this patient, but imiquimod 5% cream, an immunomodulator, clinically cleared his cutaneous disease.

AIDS-Related Opportunistic Infections↗

Activating and dominant inactivating c-KIT catalytic domain mutations in distinct clinical forms of human mastocytosis.

Human mastocytosis is characterized by increased mast cells. It usually occurs as a sporadic disease that is often transient and limited in children and persistent or progressive in adults. The c-KIT protooncogene encodes KIT, a tyrosine kinase that is the receptor for mast cell growth factor. Because mutated KIT can transform cells, we examined c-KIT in skin lesions of 22 patients with sporadic mastocytosis and 3 patients with familial mastocytosis. All patients with adult sporadic mastocytosis had somatic c-KIT mutations in codon 816 causing substitution of valine for aspartate and spontaneous activation of mast cell growth factor receptor (P = 0.0001). A subset of four pediatric onset cases with clinically unusual disease also had codon 816 activating mutations substituting valine, tyrosine, or phenylalanine for aspartate. Typical pediatric patients lacked 816 mutations, but limited sequencing showed three of six had a novel dominant inactivating mutation substituting lysine for glutamic acid in position 839, the site of a potential salt bridge that is highly conserved in receptor tyrosine kinases. No c-KIT mutations were found in the entire coding region of three patients with familial mastocytosis. We conclude that c-KIT somatic mutations substituting valine in position 816 of KIT are characteristic of sporadic adult mastocytosis and may cause this disease. Similar mutations causing activation of the mast cell growth factor receptor are found in children apparently at risk for extensive or persistent disease. In contrast, typical pediatric mastocytosis patients lack these mutations and may express inactivating c-KIT mutations. Familial mastocytosis, however, may occur in the absence of c-KIT coding mutations.

Adult↗

Once-weekly fluconazole (450 mg) for 4, 6, or 9 months of treatment for distal subungual onychomycosis of the toenail.

BACKGROUND: Fluconazole is a bis-triazole antifungal agent approved for the treatment of oropharyngeal, esophageal, and vaginal candidiasis, serious systemic candidal infections, and cryptococcal meningitis. OBJECTIVE: The purpose of this study was to evaluate three different durations of once-weekly fluconazole for the treatment of onychomycosis of the toenail caused by dermatophytes. METHODS: In a multicenter, randomized, double-blind, parallel, placebo-controlled trial, 384 patients with distal subungual onychomycosis of the toenail received fluconazole, 450 mg once weekly, or placebo for 4, 6, or 9 months. For inclusion, patients were required to have mycologically confirmed distal subungual onychomycosis of the toenail with a large toenail at least 25% clinically affected but having at least 2 mm of healthy nail between the nail fold and the proximal onychomycotic border. Efficacy was assessed by clinical and mycologic (microscopic and microbiologic) measures at screening, at every treatment visit starting at month 3, and at months 2, 4, and 6 after therapy. Observed or volunteered adverse events were recorded and classified at all visits. RESULTS: At the end of treatment, very significantly superior clinical and mycologic results were achieved in all fluconazole groups compared with placebo (p=0.0001). This superiority was largely maintained over 6 months of follow-up. The clinical and mycologic responses of the 9-month treatment duration were significantly superior to the 4- and 6-month durations. Similar percentages of patients in the fluconazole and placebo groups reported adverse experiences for all three durations of the study. CONCLUSION: Results of this study support the efficacy and safety of fluconazole in the treatment of distal subungual onychomycosis of the toenail.

Adolescent↗

Complications associated with intraperitoneal 32P.

The charts of all patients having received intraperitoneal 32P in the Indiana University Department of Radiation Oncology were retrospectively reviewed for complications and potentially related factors. Ninety-five patients had received this therapy, with a mean follow-up of 43.6 months. The majority of patients (81) had ovarian cancer. Complications were defined as mild if no intervention was required, moderate if medical intervention was required, and severe if the event was life-threatening or required surgical correction. Twenty patients (21%) had acute side effects recorded, with 15 of them (16%) being mild. The moderate complications (five patients) consisted of three cases of bowel obstruction, and two cases of abdominal pain requiring narcotics. There were no severe acute side effects. Chronic complications were found in 15 patients (20% actuarial 5-year incidence). Seven cases were mild (12% 5-year incidence), one was moderate (1%), and seven cases were classified as severe (7.4% 5-year incidence). All moderate and severe cases were bowel obstructions. Acute side effects were found to be related only to the volume of instillate (P = 0.049). Chronic complications were found to be related only to adjunctive pelvic/abdominal radiotherapy, with a 44% 5-year rate in patients receiving the combination having complications vs 17% (P = 0.04) (or 4.7% if mild complaints are excluded, P = 0.002) of those with 32P only. Comparison is made to other reports in the literature.

Acute Disease↗

Proliferation cell nuclear antigen and soluble interleukin 2 receptor levels in cutaneous T cell lymphoma: correlation with advanced clinical diseases.

Cutaneous T-cell lymphoma and leukemias (CTCL) are malignant clonal proliferation of T lymphocytes which have a predilection to home to and proliferate in skin. There are no clinical and laboratory parameters which consistently correlate with stage of disease, which varies from patch, plaque, tumor, or erythroderma. Soluble IL-2 receptor (sIL2-R) levels are elevated both in benign and malignant diseases involving immune activation. Proliferation cell nuclear antigen (PCNA) is a marker of the G1 and G/S phases of cell cycle and can be used to quantitate proliferation. We studied 43 skin biopsies of CTCL in various clinical stages for the presence of PCNA via immunoperoxidase techniques to establish a relationship between PCNA and the stage of disease. In addition, sIL2-R levels were determined in 14 patients. PCNA reactivity was detected in the nuclei of infiltrating cells in a total of 25 patients (58%). According to clinical stage there were 2/12 patch (12%), 9/17 plaque (53%), 4/4 tumor (100%) and 9/10 erythrodermic (90%) stage patients with PCNA positive cells. Thus PCNA positivity correlated with advanced clinical stage. sIL2-R levels were elevated in 14 of 14 patients and the degree of elevation correlated with advanced clinical stage of disease and with increased numbers of PCNA positive cells. Immunohistochemical studies for PCNA and serum sIL2-R levels can be used as laboratory parameters to correlate with clinical stage of disease and enhance prognostication in CTCL.

Humans↗

Dystrophin-deficient myofibers are vulnerable to mast cell granule-induced necrosis.

Duchenne muscular dystrophy is the most common inherited lethal X-linked disorder of mankind and is caused by dystrophin deficiency. The steps involved in the dystrophin-deficiency-induced cascade which lead to myofiber necrosis, progressive muscle wasting in humans and dogs and prominent muscle hypertrophy in mice and cats are obscure. Dystrophin is an intracellular component of the membrane cytoskeleton and its absence would be expected to cause necrosis of isolated myofibers (cell autonomous defect). However, all dystrophin-deficient muscles characteristically show simultaneous degeneration of large groups of muscle fibers (grouped necrosis). This implies that cell death may be mediated by extracellular, non-cell autonomous factors which occur as a secondary consequence of dystrophin deficiency. We have proposed a model where tissue pathology may be mediated by infiltrating mast cells (Gorospe et al., J Neurol Sci 1994). Here we show that intramuscular injections of purified mast cell granules induce widespread myofiber necrosis in dystrophin-deficient mdx mice, but not in normal mice. These data support the hypothesis that dystrophin acts as a plasma membrane stabilizer and that its deficiency renders myofibers more susceptible to damage from mast cell proteases. Moreover, our results support the hypothesis that mast cell degranulation may be a trigger for myofiber death in dystrophin-deficient muscle.

Animals↗

Urticaria: clinical efficacy of cetirizine in comparison with hydroxyzine and placebo.

Chronic urticaria is a problem for both physician and patient. In an effort to avoid the risks associated with corticosteroid treatment, many first-generation H1-receptor antagonists have been tried and found to induce undesirable levels of sedation when given in amounts sufficient to control urticaria. Cetirizine, a pharmacologically active oxidized metabolite of hydroxyzine, was developed to provide selective H1-receptor inhibition without depression of the central nervous system. In a 4-week, multicenter, double-blind, placebo-controlled safety and efficacy study, cetirizine, in a once-a-day dose (5 to 20 mg), was equivalent in efficacy to hydroxyzine in divided doses (25 to 75 mg/day). The incidence of somnolence in the cetirizine group was not significantly different from that of the placebo group. However, in the hydroxyzine group, the incidence of somnolence was significantly higher than that in the placebo group (p = 0.001). The results of this study demonstrate that cetirizine has a greater safety margin over the older parent drug hydroxyzine.

Adolescent↗

Possible role of Epstein-Barr virus infection in cutaneous T-cell lymphomas.

Although cutaneous T-cell lymphoma (CTCL) is a neoplastic helper T-cell disorder of unknown etiology, prolonged antigenic stimulation has been postulated to contribute to the development of this disease. Because Epstein-Barr Virus (EBV) infection has been associated with several different lymphomas, the sera of 21 CTCL patients were examined for antibodies to EBV antigens. By using complement immunofluorescence (CIF) techniques, 13 of 21 CTCL patients had detectable antibodies to Epstein-Barr Nuclear Antigens (EBNA), whereas only five of 20 control psoriatic patients were CIF positive. When immunoblot analysis was employed, all 21 of the CTCL patients had antibodies to the EBV antigens, EBNA, whereas only 12 of the control patients had detectable antibodies to these antigens. In addition, three of 21 CTCL patients had antibodies to the EBV-associated antigen, rheumatoid arthritis nuclear antigen (RANA), as determined by double immunodiffusion, whereas none of the control sera contained anti-RANA antibodies. These results indicate that antibodies against EBV antigens are found with a higher frequency and concentration in patients with CTCL when compared to controls and suggest that EBV products might serve as a possible stimulus for the development of this malignant disease.

Adult↗

Establishment of a human cutaneous T-cell lymphoma in C.B-17 SCID mice.

Investigation into the immunobiology of cutaneous T-cell lymphomas (CTCL) would be facilitated by the development of a suitable experimental system. The recent use of mice with severe combined immune deficiency (SCID) as a vehicle to study the human immune system prompted us to try to establish CTCL in SCID mice. We found that a CD4+ lymphocytic infiltrate characteristic of CTCL was maintained within patient skin grafts in place on natural killer cell depleted SCID mice for the month of observation. CTCL cells were not found outside the human skin graft. This chimeric model using SCID mice and patient lesional skin should provide a useful tool to characterize CTCL/skin microenvironmental interactions and to test new therapeutic approaches.

Animals↗