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Biomedical subjects

S Omar

Publications and source records attributed to S Omar.

At least 55 records · Page 3Linked to original sources
PubMed1986

Postoperative radiotherapy of carcinoma in bilharzial bladder using a three-fractions per day regimen.

Patients with T3 bladder cancer who survived surgery and proved to have P3a, P3b or P4a tumors were randomized to either no further treatment (61 patients) or postoperative total pelvic irradiation (55 patients). A three-fraction per day regime was adopted with a dose per fraction of 125 cGy and an interval of 3 h between fractions. The total dose amounted to 3750 cGy divided into 30 fractions over 12 days. Patients of the postoperative radiotherapy group were re-randomized to radiotherapy alone or radiotherapy plus misonidazole (MISO) in a daily dose of 1 g/m2 given orally 2 h before the first daily fraction. The 2-year disease-free survival rate in the cystectomy alone group was 33 +/- 6% compared to 65 +/- 6% in the postoperative radiotherapy group. The therapeutic benefit applied to the two cell types, all histological grades and stages and to patients with or without nodal metastases. The benefit of postoperative irradiation was also verified by the Cox's multivariant analysis which adjusts for the relative representation of the important prognostic factors particularly pathological stage and nodal involvement. MISO did not seem to add to the therapeutic gain. No late complications were encountered in the wall of the rectum, small bowel or uretero-intestinal anastomotic sites. This is suggested to be due to the small dose per fraction used. However, early small bowel reactions were dose-limiting.

Adult↗
PubMed1983

The use of misonidazole in association with a three-fractions per day regimen in advanced head and neck epidermoid cancer. A pilot study.

Twenty-one patients with Stage III or IV head and neck epidermoid cancer were treated by a three-fractions per day radiotherapy regime plus misonidazole (MIS). An initial course of 45 Gy was used, spread over 12 days and divided into 30 fractions 1.5 Gy each with a 3-hour interval between fractions. A daily MIS dose of 1 g/m2 was given 2 hours prior to the first fraction. A boost dose of 22.5 Gy/5 days was given to 10 patients, 4 weeks after the initial course, using the same fractionation scheme. The local acute and chronic reactions were acceptable. Eight patients suffered mild reversible peripheral neuropathy. The mean MIS blood level corresponded to an enhancement ratio of about 1.45. The 1-year disease-free survival rate was 9/21 and was significantly greater in patients receiving the boost irradiation. The control rate of nodal disease was encouraging. Based on this pilot study, a prospective trial is proposed aiming at testing the usefulness of MIS in MDF regimens in advanced head and neck cancer, either as the sole method of treatment or as a preoperative measure.

Adult↗
PubMed1983

The topical use of misonidazole in bladder cancer.

Penetration studies of MIS after intravesical administration showed adequate concentrations with a gradient across the tumor. After instillation of 2.5 g in 50 ml water the concentration in the deep parts of the tumor amounted to about 100 microgram per ml. This corresponds to a SER for hypoxic cell of the order of 1.7. A more uniform tissue distribution of the drug was noted 3.5 hours after an oral dose of 3 g/meter square. The concentration in the deep parts of the tumor and perivesical tissue was of the order of 100 micrograms/g. The concentration in these regions are relevant to preoperative irradiation which aims at sterilizing the deep infiltrating margins. The intravesical use with or without oral augmentation is suitable for use in association with concentrated preoperative radiotherapy regimens. The topical use of MIS in such regimens markedly reduces the risk of neurotoxicity. The tissue concentration resulting from the two routes proved to be additive. The higher concentration in lymph nodes after the oral route the greater concentration and prolonged contact after combined administration may have therapeutic merits.

Administration, Oral↗
PubMed1980

Retroperitoneal block dissection in the treatment of nonseminomatous tumors of the testis.

Fifteen patients with nonseminomatous tumors of the testis, stages I and II, underwent a retroperitoneal block dissection as part of their treatment regimen. Nonseminomatous germ cell and paratesticular tumours were reported. The preoperative measures and operative technique of the anterior transabdominal approach are described. There were no deaths or major postoperative complications encountered, in spite of the magnitude of the surgery involved. In two patients the tumor had occurred in an undescended testis. No patient had normal ejaculatory function after the operation. Special attention is drawn to the proper management of patients having undergone a transscrotal biopsy or orchiectomy. Five patients with a relatively long-term follow-up, are free of disease and doing well.

Adolescent↗
PubMed1979

Histidyl and tyrosyl residue ionization studies of subtilisin Novo.

The low field portion of the 360 MHz 1H nuclear magnetic resonance spectrum of phenylmethanesulfonyl-subtilisin Novo (EC 3.4.21.14) has been studied as a function of pH. Analysis of the pH-induced chemical shift changes occurring between 6 to 7 ppm revealed five classes of ionizable residues with pK values (uncorrected) of 10.3, 10.7, 10.7, 10.8, and 11.0. With a single exception the titration curves can be fit by assuming a simple proton ionization equilibrium. Four classes of low intensity broad resonances, assigned to the histidyl residues, are observed between 8 and 9 ppm. Uncorrected pK values of 5.4, 5.7, 6.0, and 6.4 were determined for the residues comprising each of these classes. The spectral data are consistent with protonation of one or more histidyl residues upon acid induced denaturation of the protein. These results are compared with those of analogues studies performed by the use of other techniques.

Chemical Phenomena↗
PubMed1979

Testicular tumors in undescended testes.

Twelve cases of malignant tumors in undescended testes were studied. Early diagnosis of these tumors was usually difficult as the testes were intrabdominal and the symptoms vague. Sixty percent of the seminoma cases were of the anaplastic aggressive variant. Early treatment of undescended testes included either orchiopexy or orchidectomy in early childhood. Exploratory laparotomy and frozen section examination of the abdominal nodes, followed by silver clip application, aided in better staging and the planning of further treatment.

Adolescent↗
PubMed1977

Quenching of the tyrosyl and tryptophyl fluorescence of subtilisins Carlsberg and Novo by iodide.

The tyrosyl and tryptophyl fluorescence of diisopropylphosphorylsubtilisins Carlsberg and Novo, respectively, is quenched efficiently by I- but is not significantly affected by Cs+. The I-quenching data were analyzed using a modified Stern-Volmer treatment (Lehrer, S.S. (1971), Biochemistry 10, 3254), yielding values for the effective fraction of accessible protein fluorescence of 90-95 and 88-92% for the tyrosyl and tryptophyl emission of diisopropyl-phosphorylsubtilising Carlsberg and Novo, respectively. Similar values were obtained pH 5 and 7. The effective collisional quenching constant depends on pH in a manner suggesting the participation of protein surface charge in the quenching mechanism. Significant singlet energy transfer (efficiency = 0.52) from tyrosyl to tryptophyl residues was inferred from the excitation spectra of diisopropylphosphorylsubtilisn Novo. The very low efficiency of energy transfer to Trp-113 in diisopropylphorphorylsubtilisin Carlsberg suggests that Trp-105 and Trp-241 are the acceptors of tyrosyl emission in the homologous Novo enzyme. The unusually low quantum yield of Trp-113 in diisopropylphosphorylsubtilisin Carlsberg together with the tryptophyl fluorescence quenching behavior of the Novo enzyme suggests that this residue is "buried" and in accessible to quenching in both enzymes. The tyrosyl quenching behavior of diisopropylphorphorylsubtilisin Carlsberg is consistent with the high degree of solvent exposure of aromatic residues evident in the X-ray model of subtilisin Novo.

Energy Transfer↗
PubMed1976

Leucine aminopeptidase, Significance of serum elevation in bilharziasis.

Leucine aminopeptidase (LAP) activity and creatinine concentration was estimated in serum of twenty five normal adult subjects, twenty four cases with active urinary bilharziasis, eleven cases with active intestinal bilharziasis, ten cases with mixed bilharzial infection (urinary and intestinal), fourteen bilharzial cases with clinical hepato-splenomegaly of bilharzial etiology, thirteen bilharzial cases with clinical hepatosplenomegaly and ascites, and twelve cases with cancer bladder of bilharzial etiology. Significant elevation in the serum enzyme level was found in all bilharzial cases which generally ran parallel to the course of the disease, being more marked in hepatosplenomegalic cases than in cases which showed no clinical signs of liver or spleen involvement. However, it was observed that the enzyme level was lower ascitic than in nonascitic cases. For serum creatinine concentration, no significant variation from normal value was observed in the group of patients with active urinary, active intestinal, mixed infections of bilharziasis and bilharzial hepatosplenomegalic cases. However, a very highly significant decrease in serum creatinine concentration was observed in the group of patients with bilharzial hepatosplenomegaly and ascites. Serum LAP activity and creatinine concentration in the group of patients with cancer bladder of bilharzial etiology showed no statistical variation from normal values.

Adult↗
PubMed1976

Urinary leucine aminopeptidase in bilharziasis.

Leucine aminopeptidase activity and total protein concentration was estimated in the fresh early morning sample of urine of twenty five normal adult subjects, twenty four cases with active urinary bilharziasis, eleven cases with active intestinal bilharziasis, ten cases with mixed bilharzial infection (urinary and intestinal), fourteen bilharzial cases with clinical hepatosplenomegaly of bilharzial etiology, thirteen bilharzial cases with clinical hepatosplenomegaly and ascites, and twelve cases with cancer bladder of bilharzial etiology. It was found that there is a significant increase in LAP activity in the urine of all groups of patients studied. Again this increase ran parallel to the course of the disease in bilharzial cases. Urine protein concentration was found to be increased significantly in all groups of bilharzial cases studied with the highest value in urine of patients with cancer bladder of bilharzial etiology. However no direct correlation was found between urinary LAP level and protein concentration either within the individual cases or within the different groups.

Adult↗
PubMedDate not supplied

Antifolate drug resistance and point mutations in Plasmodium falciparum in Kenya.

Due to increased chloroquine resistance, the antifolate/sulpha drug combinations are becoming increasingly important in the chemotherapy of falciparum malaria. However, point mutations in the dihydrofolate reductase gene lead to resistance to the antifolate drugs. We therefore investigated the prevalence of the 6 reported point mutations in this gene among field isolates of Plasmodium falciparum from Kenya, to determine if the mutations correlated with resistance to pyrimethamine and the biguanides cycloguanil and chlorcycloguanil. We used a mutation-specific polymerase chain reaction technique to test for these reported mutations in 21 Kenyan isolates and 4 reference lines. We also amplified and directly sequenced the dihydrofolate reductase coding sequence from these parasites to confirm the results and test for other possible mutations. Of the reported mutations, we found S108N, which is the central mutation of pyrimethamine resistance, and mutations N51I and C59R, which modulate the levels of resistance and may confer decreases in response to cycloguanil that are folate and p-aminobenzoic acid dependent. No isolate possessed the paired point mutations S108T and A16V, or I164L and S108N, which have been associated with cycloguanil resistance in previous studies. These results provided supportive evidence for the combined use of a cycloguanil-class drug (e.g., chlorproguanil) and a sulpha drug (e.g., dapsone) against P.falciparum malaria in Kenya.

Animals↗
PubMedDate not supplied

Root caries among Benghazi patients.

A total of 420 Benghazi patients were clinically examined for root caries. Root caries was not limited to older patients and the proportion of root caries among young adults was similar to that of the older age groups. Most of the lesions were located proximally and underneath restorations rather than labially or lingually. Our results may serve as baseline data for further studies on root caries in the Libyan Arab Jamahiriya.

Adolescent↗
PubMedDate not supplied

[The etiology of hypercalcemia: a study of 47 cases in a hospital internal medicine service].

In this study, we are presented the clinical and the aetiologic features of 47 patients having hypercalcemia (total serum calcium > or = 2.7 mmol/l). Our results show a positive significantly correlation between the degree of the hypercalcemia and the severity of the clinical symptomatology. As for to the aetiology, the multiple myeloma, the hyperparathyroid and the neoplastic process constituted 78% of the total aetiology.

Aged↗
PubMedDate not supplied

[Serum copper levels in obesity: a study of 32 cases].

Abnormalities of copper distribution in tissues and serum has been described in obese subjects. In this prospective study, we evaluated the seric level of copper by atomic absorption in a group of 32 obese (BMI > or = 30 kg/m2) compared to a group of 32 healthy subjects. We have noted an elevation of serum copper in obese with a middle level of 133 mg/dl significantly superior to the middle level of serum copper of healthy subjects, 108 mg/dl (p < 0.001). In another hand, we have noticed that the levels of serum cooper rise with the BMI. In fact, 58.3% of the obese that have a BMI > or = 40 kg/m2 show a high concentration of serum copper although only 5% of obese with BMI < 40 kg/m2 show this high concentration. This work must be completed by the determination of ceruloplasmin levels in a larger group of obese in order to establish correlations between the serum ceruloplasmin levels, the serum copper levels and the obesity.

Adult↗