Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018681 (headache)
 56,091 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vitamins contain reactive functional groups necessary to their established roles as coenzymes and reducing agents. Their reactive potential may produce injury if vitamin concentration, distribution, or metabolism is altered. However, identification of vitamin toxicity has been difficult. The only well-established human vitamin neurotoxic effects are those due to hypervitaminosis A (pseudotumor cerebri) and pyridoxine (sensory neuropathy). In each case, the neurological effects of vitamin deficiency and vitamin excess are similar. Closely related to the neurological symptoms of hypervitaminosis A are symptoms including headache, pseudotumor cerebri, and embryotoxic effects reported in patients given vitamin A analogs or retinoids. Most tissues contain retinoic acid (RA) and vitamin D receptors, members of a steroid receptor superfamily known to regulate development and gene expression. Vitamin D3 effects on central nervous system (CNS) gene expression are predictable, in addition to the indirect effects owing to its influence on calcium and phosphorus homeostasis. Folates and thiamine cause seizures and excitation when administered in high dosage directly into the brain or cerebrospinal fluid (CSF) of experimental animals but have rarely been reported to cause human neurotoxicity, although fatal reactions to i.v. thiamine are well known. Ascorbic acid influences CNS function after peripheral administration and influences brain cell differentiation and 2-deoxyglucose accumulation by cultured glial cells. Biotin influences gene expression in animals that are not vitamin-deficient and alters astrocyte glucose utilization. The multiple enzymes and binding proteins involved in regeneration of retinal vitamin A illustrate the complexity of vitamin processing in the body. Vitamin A toxicity is also a good general model of vitamin neurotoxicity, because it shows the importance of the ratio of vitamin and vitamin-binding proteins in producing vitamin toxicity and of CNS permeability barriers. Because vitamin A and analogs enter the CNS better than most vitamins, and because retinoids have many effects on enzyme activity and gene expression, Vitamin A neurotoxicity is more likely than that of most, perhaps all other vitamins. Megadose vitamin therapy may cause injury that is confused with disease symptoms. High vitamin intake is more hazardous to peripheral organs than to the nervous system, because CNS vitamin entry is restricted. Vitamin administration into the brain or CSF, recommended in certain disease states, is hazardous and best avoided. The lack of controlled trials prevents us from defining the lowest human neurotoxic dose of any vitamin. Large differences in individual susceptibility to vitamin neurotoxicity probably exist, and ordinary vitamin doses may harm occasional patients with genetic disorders.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Vitamin neurotoxicity. 146 88

This is the first report in Israel of the successful treatment of acute promyelocytic leukemia (APL; M3) with an active metabolite of vitamin A. In a 42-year-old woman with APL all-trans-retinoic acid (ATRA; tretinoin), 45 mg/m2/day was given per os for 90 days. APL is associated with a distinct cytogenetic abnormality: translocation of a portion of the long arm chromosome 17 onto the long arm chromosome 15t (15; 17) with a breakpoint on chromosome 17 in the region of the retinoic acid receptor-alpha (RAR-alpha), playing a crucial role in the leukemogenesis of APL. In man, the drug induces myeloid and mainly promyelocytic leukemic cells to differentiate, without the development of bone marrow hypoplasia. In our patient it caused complete remission and the disappearance of intravascular disseminated coagulation. The only side-effects were a transient macular rash, gastrointestinal symptoms and mild hypertriglyceridemia. Other principal adverse effects reported in the literature are relatively not very serious and consist of dryness of the skin, occasional headaches and intracranial hypertension, nasal congestion, lymphadenopathy, respiratory distress with infiltrates in the lung, bone pain and increased hepatic aminotransferase. A hyperleukocytosis syndrome seems to be more problematic. ATRA appears to be superior to conventional chemotherapeutic regimens. It is safe and highly effective in inducing clinical, morphologic and karyotypic remission with a marked decrease in the expression of the abnormal RAR-message in APL. There is a possible molecular link between the pathogenesis and treatment of this severe and often fatal coagulopathic disease. This therapy of course does not eradicate the leukemic clone, and consolidation chemotherapy or bone marrow transplantation is necessary.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Remission of acute promyelocytic leukemia after all-trans-retinoic acid]. 148 98

Twenty-four patients with acute promyelocytic leukemia (APL) were treated with all-trans retinoic acid (45 to 100 mg/m2/day). Of these, eight cases had been either nonresponsive or resistant to previous chemotherapy; the other 16 cases were previously untreated. All patients attained complete remission without developing bone marrow hypoplasia. Bone marrow suspension cultures were studied in 15 of the 24 patients. Fourteen of these patients had morphological maturation in response to the retinoic acid (1 mumol/L). Chloroacetate esterase and alpha-naphthyl acetate esterase staining as well as electronmicroscopic examination confirmed that retinoic acid-induced cells differentiated to granulocytes with increased functional maturation (as measured by nitroblue tetrazolium reduction, NBT). The single nonresponder to retinoic acid in vitro was resistant to treatment with retinoic acid but attained complete remission after addition of low-dose cytosine arabinoside (ara-C). During the course of therapy, none of the patients showed any abnormalities in the coagulation parameters we measured, suggesting an absence of any subclinical disseminated intravascular coagulation. The only side effects consisted of mild dryness of the lips and skin, with occasional headaches and digestive symptoms. Eight patients have relapsed after 2 to 5 months of complete remission. The others remain in complete remission at 1+ to 11+ months and are still being followed up. We conclude that all-trans retinoic acid is an effective inducer for attaining complete remission in APL.
 ...
PMID:Use of all-trans retinoic acid in the treatment of acute promyelocytic leukemia. 316 95

In an attempt to increase the peak plasma levels of 13-cis-retinoic acid (13-cis-RA) and its efficacy in vivo, a Phase I study and pharmacokinetics of weekly high-dose, oral 13-cis-RA was conducted in 23 cancer patients who were refractory to conventional treatments. At 200 mg/sq m, the mean peak plasma level of 13-cis-RA was 1.5 +/- 0.1 (SE) micrograms/ml; at 400 mg/sq m, the mean peak plasma level increased to 3.8 +/- 0.7 micrograms/ml. Further increases of the 13-cis-RA dose up to 1800 mg/sq m did not lead to proportional increases in either the mean peak plasma levels or area under the curve, indicating a saturable absorption phenomenon. The terminal half-life was highly variable (range, 2.8 to 101.3 h) and was not related to the dose given. A secondary peak plasma concentration was seen in five patients, suggesting enterohepatic circulation. The toxicities such as headache, cheilitis, dry skin, and dry eyes were frequent on the weekly schedule but were not dose-limiting. One patient had an elevation of the triglycerides of 2 to 5 times the upper limit of normal; five patients had an elevation of 1.1 to 2 times normal. No objective responses were observed to treatment with 13-cis-RA. Of 20 patients receiving an adequate trial of the drug, 18 showed progression of their cancer, and two had stable disease.
 ...
PMID:Phase I study and pharmacokinetics of weekly high-dose 13-cis-retinoic acid. 397 47

We investigated the effect of the synthetic vitamin A derivative isotretinoin (13-cis-retinoic acid) on advanced cancers in 103 patients and on preneoplastic lesions in five patients. Six of 14 patients with squamous cell epithelial cancers had objective regressions of skin or subcutaneous metastases. Three of five patients with preneoplastic lesions had objective responses. The major dose-limiting toxic effects were reversible dermatitis, emotional lability, and headaches. We conclude that the growth of some squamous cell epithelial malignancies can be inhibited by isotretinoin and suggest that other retinoids should be evaluated as antitumor agents.
 ...
PMID:Activity of isotretinoin against squamous cell cancers and preneoplastic lesions. 621 Dec 33

This study shows that severe acne is characterized by numerous inflammatory parameters. The group of acne tetrad patients differed from those with conglobate acne in many laboratory measurements. The treatment with 13-cis-retinoic acid was well tolerated by all patients. Sebum suppression and an exfoliative cheilitis occurred in all patients, but no headache and no loss hair. Numerous previously pathological blood chemical values were normalized during the treatment. Transaminases, alkaline phosphatase, triglycerides and total cholesterol did not rise noticeably, trichological and spermatological parameters were not affected by 13-cis-retinoic acid. In an in vivo epicutaneous potassium iodide inflammation model, it was possible to demonstrate for the first time the anti-inflammatory action of 13-cis-retinoic acid.
 ...
PMID:[13-cis-Retinoic acid. Pharmacologic and toxicologic findings in treatment of severe forms of acne (author's transl)]. 645 Aug 94

A phase I study of 13-cis-retinoic acid was done in 16 patients with head and neck malignancies using a modified Fibonacci search scheme, with individual doses ranging from 20 to 120 mg/m2. Drug doses greater than 60 mg/m2 induced intense headaches, urethritis, desquamative dermatitis, vertigo, and ataxia. The severity of these side effects precludes the use of 13-cis-retinoic acid as a potential chemopreventive agent at doses greater than 60 mg/m2.
 ...
PMID:Phase I study of 13-cis-retinoic acid toxicity. 711 51

A 27-year-old Chinese woman with acute promyelocytic leukaemia in first relapse after the initial conventional induction chemotherapy 18 months earlier was treated with all-trans retinoic acid (ATRA) at an initial dose of 45 mg/m2 and subsequently increased to 65 mg/m2 on day 15. Complete remission was achieved after a total of 40 days of ATRA alone. Serial marrow examinations during induction showed progressive maturation of myelopoiesis without bone marrow hypoplasia. There was a significant reduction in number of cells with the t(15;17) translocation when complete remission was achieved. ATRA was very well-tolerated. The symptoms of dry skin and intermittent headache were self-limiting.
 ...
PMID:Treatment of acute promyelocytic leukaemia in first relapse with all-trans retinoic acid. 760 89

A rare variant of acute promyelocytic leukemia (APL) is associated with basophilic differentiation. Such a patient presented with basophilia, headaches, and diffuse engorgement of superficial blood vessels, attributable to hyperhistaminemia. Karyotype analysis showed a clonal rearrangement of chromosome 12p13 in addition to the t(15;17). During treatment with all-trans-retinoic acid (TRA), the absolute basophil count rose steadily during the first week, then declined. By one month, the basophilia resolved, an abrupt rise occurred in both the platelet and absolute neutrophil count, and the bone core biopsy showed complete maturation of all cell lines. Abnormalities of chromosome 12p13 in acute myelogenous leukemia have been associated with basophilia. Since every cell in our patient with t(12p13;?) also had the t(15;17), we speculate that the basophilia was due to clonal evolution with acquisition of the t(12p13;?). In two out of five other reported cases, abnormalities of chromosomes known to be associated with basophilia were present in addition to t(15;17). It is possible that the basophilia in this variant is reactive; however, since TRA induces differentiation of leukemic promyelocytes into mature neutrophils, we speculate that the leukemic promyelocytes in our patient differentiated into basophils. Future studies employing either fluorescent in situ hybridization or polymerase chain reaction using a probe to the breakpoint on t(15;17) may establish whether or not the basophils derive from the leukemic clone.
 ...
PMID:Basophilic differentiation in acute promyelocytic leukemia. 784 22

Retinoids have anti-tumor activity in several malignant and premalignant conditions. Since Kaposi's sarcoma is regulated by steroid hormones both in vivo and in vitro, we hypothesized that retinoids may have anti-tumor effects in AIDS-related Kaposi's sarcoma. Thus, 27 patients with mucocutaneous, non-visceral AIDS-related Kaposi's sarcoma were treated with all-trans retinoic acid (tRA). Poor tolerance was observed at the initial starting dose of 150 mg/m2, and thus subsequent patients were treated using a weekly dose escalation, starting with 45 mg/m2 (given daily, in subdivided doses), to the target dose of 150 mg/m2 (given daily in three subdivided doses). Nearly half (46%) of the patients had extensive mucocutaneous disease with over 25 lesions. No patient had received prior cytotoxic chemotherapy. Ten patients had CD4 lymphocytes of 200/mm3 or greater (strata I); and 17 had under 200/mm3 CD4 lymphocytes (strata II). The median of the average daily tRA dose administered was 150 mg (90 mg/m2; there was no significant difference in the dose tolerance between the two strata). Adverse effects consisted of transient mild to moderate headaches in 65% of patients, mild to moderate skin dryness and cheilitis in 61%, and nausea and vomiting in 31%. Hematologic toxicities included hypertriglyceridemia in 62%, anemia in 23%, and neutropenia in 23%. Partial response to therapy was observed in 4/24 (17%) evaluable patients, occurring after 12, 20, 24, and 28 weeks of therapy, and lasting 4-24 weeks. Three responders had baseline CD4 lymphocyte counts < 200/mm3. Three additional patients experienced reduction in measured indicator lesions of greater than 25% but less than 50%, and seven patients experienced disease stabilization of 16 weeks or greater. In evaluable patients, the median time to disease progression was 22 weeks and the overall median survival in all patients was 27.3 months. No significant changes in CD4 lymphocyte counts, p24 antigen, and beta 2 microglobulin were observed over time. However, a statistically significant increase was observed in soluble IL-2 receptor levels while on tRA (p = 0.037). We conclude that tRA has activity in patients with mucocutaneous AIDS-related Kaposi's sarcoma with acceptable toxicity. tRA has immunological effects without upregulation of HIV parameters. Additional studies in combinations or with more active retinoids are warranted.
 ...
PMID:All-trans retinoic acid for the treatment of AIDS-related Kaposi's sarcoma: results of a pilot phase II study. 780 21


1 2 3 4 5 6 Next >>