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Biomedical subjects

A Segal

Publications and source records attributed to A Segal.

At least 73 records · Page 4Linked to original sources

[Melanoma of the uvea in young patients. Apropos of 3 cases].

The authors report 3 cases of uveal melanoma, appeared on young women: 20, 23 and 28 years old. The melanomas were localized on the iris, the ciliary body and on the choroid. The authors studied the different notions of the literature about happened age of these lesions.

Adult↗

In vitro reactions of glycidol with pyrimidine bases in calf thymus DNA.

The 3-carbon epoxide glycidol (GLC) was reacted with dCyd and dThd at pH 7.0 to 7.5 and 37 degrees C for 10 h. The only product detected from the reaction with dCyd was 3-(2,3-dihydroxypropyl)-dUrd (3-DHP-dUrd) whose structure was established from UV spectra, isobutane chemical ionization (CI) mass spectra together with accurate mass measurements and synthesis of 3-DHP-dUrd from reactions of GLC with dUrd. Reaction of GLC with dThd gave a single product, 3-DHP-dThd, whose structure was established from UV spectra and CI mass spectra together with accurate mass measurements. The compounds, 3-DHP-dUrd and 3-DHP-dThd, were identified and quantitated following in vitro reaction of GLC with calf thymus DNA at pH 7.0 to 7.5 and 37 degrees C for 10 h. The amounts of 3-DHP-dUrd and 3-DHP-dThd formed were 10 and 1 nmol/mg DNA respectively. Alkylation at the N-3 position of Cyt resulted in a rapid hydrolytic deamination of Cyt to form a Ura adduct. This phenomena was previously reported by us following reaction of propylene oxide (PO) with dCyd and following in vitro reaction of PO with calf thymus DNA under identical conditions. The rapid hydrolytic deamination of Cyt to Ura may be a general occurrence following alkylation of N-3 of Cyt by 3-carbon epoxides and is postulated to be related to the presence of a C-2 hydroxyl group on the 3-carbon propyl side chain. The implications of this newly discovered lesion in DNA in terms of the mutagenicity of GLC (and PO) remain to be elucidated.

1-Propanol↗

[Retinal detachment caused by desinsertion at the ora serrata. Epidemiologic aspects and prognosis].

A study about 44 retinal detachments showed 44 cases of retinal detachment due to desinsertions at the ora serrata, including all etiologies. We found that most of the cases were young people (80% before 40 years old), and male and functional results were relatively poor (60%). In "idiopathic" cases and due to the ocular contusions, the rates of good anatomic results were respectively 86% and 95%, and visual acuity was improved in 70% and 81% of the eyes.

Adolescent↗

Multicenter evaluation of triamcinolone acetonide nasal aerosol in the treatment of adult patients with seasonal allergic rhinitis.

Triamcinolone acetonide aerosol inhalation therapy is effective for the prophylactic treatment of asthma. Recently, the delivery system for this preparation has been modified for use in allergic rhinitis. A total of 180 adult patients with symptomatic seasonal allergic rhinitis participated in this double-blind, placebo-controlled, multicenter trial. Patients received either placebo or approximately 25 mg per actuation of triamcinolone acetonide aerosol per nostril, qid, for 4 weeks. Each patient kept a daily diary rating rhinitis symptoms. Both the patient and the physician also gave global evaluations of drug efficacy. Of 168 evaluable patients, significant reductions were seen at week 1, week 2, and in the overall study evaluation of ratings for intensity (P less than .001) and duration (P less than .05) of various rhinitis symptoms such as nasal stuffiness, discharge, and sneezing in the group given triamcinolone acetonide. Superiority to placebo group was evident as early as day 1 and maintained throughout the study. Both patients and physicians rated triamcinolone acetonide as significantly more effective than placebo for the duration of the study (P less than .001). There was a marked reduction in nasal smear eosinophils in the triamcinolone acetonide group. There was no difference between groups in safety evaluations including no evidence of suppression of the adrenal axis and no evidence of fungal infection. This study demonstrates that triamcinolone acetonide in a dose of 25 micrograms per nostril, qid, is effective, well tolerated, and safe in reducing symptoms in adult patients with seasonal allergic rhinitis.

Administration, Intranasal↗

Inhibition of soybean lipoxygenase and mouse skin tumor promotion by onion and garlic components.

Onion and garlic essential oils were previously shown to inhibit mouse skin tumor promotion, as were the enzymes, lipoxygenase, and cyclooxygenase. In the present study, the inhibition of soybean lipoxygenase (EC 1.13.11.12) by onion and garlic components and related compounds was investigated. The IC50 values as well as the kinetic inhibition constants were determined for the most active compounds. Di-(1-propenyl) sulfide, an analog of the substrate moiety required for oxygenase action, was the only irreversible inhibitor observed with Ki = 59 microM and k3 = 0.53/min. Inhibition in the presence of substrate was uncompetitive at 88 and 132 microM linoleic acid with Ki = 129 microM. At 173 microM linoleic acid, however, inhibition was competitive with Ki = 66 microM. Dially trisulfide, allyl methyl trisulfide, and diallyl disulfide were competitive inhibitors, while 1-propenylpropyl sulfide and (E, Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide (ajoene) were mixed inhibitors. Nordihydroguaiaretic acid (NDGA), the most potent lipoxygenase inhibitor, was a competitive inhibitor with Ki = 0.29 microM. The results indicate a relative potency of inhibition for structural features in the following order: di(1-propenyl) sulfide greater than an alkenyl trisulfide greater than an alkenyl disulfide. Di(n-propyl) disulfide, a major onion oil component, inhibited neither lipoxygenase nor promotion. Di(1-propenyl) sulfide and ajoene inhibited both. This suggests that the inhibition of lipoxygenase may be involved in antipromotion.

Allium↗

Isolation of methylcarbamoyl-adducts of adenine and cytosine following in vitro reaction of methyl isocyanate with calf thymus DNA.

Methylisocyanate (MIC) is the direct-acting acylating compound involved in the Bhopal, India disaster which occurred on December 3rd, 1984. The accidental release of MIC resulted in at least 2000 deaths, thousands of injuries and exposure of at least 200,000 people to varying amounts of MIC. We have studied how MIC reacts with 2'-deoxyribonucleosides at pH 7.0 and 37 degrees C for 1 h. MIC acylates exocyclic amino groups resulting in the following methylcarbamoyl (MC) adducts: N6-MC-Ade (0.5% yield) and N4-MC-dCyd (6%). No adducts were detected with dThd and dGuo. UV, NMR and mass spectrometry were employed to spectroscopically characterize these adducts. MIC was reacted with calf thymus DNA (pH 7.0, 37 degrees C, 1 h) and yielded N6-MC-Ade (0.3 nmol/mg DNA) and N4-MC-dCyd (2.0 nmol/mg DNA). The inability of others to observe genetic mutations by MIC in Salmonella and Drosophila is consistent with the exocyclic adducts at N4 of Cyt and N6 of Ade where normal hydrogen bonding can occur after rotation of the methylcarbamoyl group anti to the Watson-Crick side of the molecule assuming that MIC binds to DNA within the intact cell.

Adenine↗

Inducibility of thymic lymphomas in female Hsd: (ICR)BR mice following subcutaneous injection of ethyl- and isopropyl methanesulfonate.

Isopropyl methanesulfonate (IMS), a direct-acting SN1 alkylating agent, induced thymic lymphomas in 29 of 30 female Hsd: (ICR)BR mice by the 139th day following once a week subcutaneous injections at a dose of 10 mumol/mouse. No such neoplasms were observed at the 450th day following 52 once a week subcutaneous injections (20 mumol/mouse) of the borderline SN1/SN2 alkylating agent ethyl methanesulfonate (EMS). Local sarcomas were observed in 2 and pulmonary adenomas in 20 of the 30 EMS-treated mice, 70% of which were alive at the 450th day. Neoplasms were not observed at local or at distant sites other than the thymus gland following treatment with IMS. The results suggest a sensitivity of hemopoietic tissue to the types of DNA lesions induced by IMS.

Animals↗

DNA adducts of propylene oxide and acrylonitrile epoxide: hydrolytic deamination of 3-alkyl-dCyd to 3-alkyl-dUrd.

Propylene oxide (PO) and acrylonitrile epoxide (ANO) are 3-carbon epoxides that are direct-acting mutagens. PO is a rodent carcinogen, and ANO has been postulated to be the ultimate carcinogenic form of acrylonitrile (AN). We have studied the reactions of these agents with 2'-deoxynucleosides and in vitro with calf thymus DNA at pH 7.0 to 7.5 and 37 degrees C. PO was reacted with DNA for 10 hr and resulted in the formation of the following 2-hydroxypropyl (HP) adducts: N6-HP-dAdo (1 nmole/mg DNA), 3-HP-Ade (14 nmole/mg DNA), 7-HP-Gua (133 nmole/mg DNA) and 3-HP-dUrd (13 nmole/mg DNA). 3-HP-dUrd was formed after initial alkylation at N-3 of dCyd followed by conversion of the adjacent exocyclic imino group at C-4 to an oxygen (hydrolytic deamination) with the formation of a dUrd adduct. ANO was reacted for 3 hr with calf thymus DNA and yielded N6-(2-hydroxy-2-carboxyethyl-dAdo (N6-HOCE-dAdo) (2 nmole/mg DNA); 1, N6-etheno-dAdo (11 nmole/mg DNA); 7-(2-oxoethyl)-Gua (7-OXE-Gua) (110 nmole/mg DNA); 3-OXE-dThd (1 nmole/mg DNA); and 3-HOCE-dUrd (80 nmole/mg DNA). As with 3-HP-dUrd, 3-HOCE-dUrd resulted from hydrolytic deamination of an initially formed dCyd adduct. A mechanism is proposed for the conversion of 3-alkyl-dCyd to 3-alkyl-dUrd involving intramolecular catalysis by the OH group on the 3-carbon side chain of the adduct.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylonitrile↗

[Inferior eyelid reconstruction. Various technics as a function of the length of substance loss].

The authors expose the three technics for the inferior eyelid reconstruction which seem them now the most certain. If the defect is inferior at the quarter of the eyelid: suture with only one junction; if it is included between the quarter and the half of this length: tarso-conjunctival graft and cutaneous flap if it surpasses the half of the eyelid length: nasal chondromucous graft and temporojugal flap.

Eyelids↗

[The visual field of patients with pituitary adenoma surgically treated].

The authors report the evolution of 72 patient's visual field operated for one pituitary adenoma. They specify the constant amelioration of this investigation in chromophobic adenomas. The stability in prolactinic adenomas or somatotropic. Allowing the supervision of the visual case, at these patients, the visual field does not seem useful in the diagnosis of the tumors recurrence.

Adenoma↗

[Surgical treatment of complete dysphagia caused by a giant cervical osteophyte].

Cervical osteophytes (due to new bone formation) occur in 30% of the population in middle or old age, but it is quite exceptional for this pathological condition to cause severe dysphagia. The authors report such a case, in which the diagnosis was confirmed by endoscopy, X-ray and computed tomography. In the absence of any curative treatment, surgery was required to relieve obstruction and an operation was performed via an antero-lateral extra-pharyngeal approach. Comparison with the literature confirms the validity of the authors decision, though some risks were involved.

Aged↗