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Biomedical subjects

M Hanna

Publications and source records attributed to M Hanna.

At least 19 recordsLinked to original sources
PubMed1991

Malignant renal tumors in tuberous sclerosis.

Although the frequency of renal carcinoma in tuberous sclerosis is lower than that in von Hippel-Lindau syndrome, it occurs bilaterally in 43 percent of patients at a median age of twenty-eight years. Concomitant hamartomas and hyperplastic cystic components may confound the histologic diagnosis of renal carcinoma in tuberous sclerosis.

Adult↗
PubMed1990

Mutational analysis of conserved nucleotides in a self-splicing group I intron.

We have constructed all single base substitutions in almost all of the highly conserved residues of the Tetrahymena self-splicing intron. Mutation of highly conserved residues almost invariably leads to loss of enzymatic activity. In many cases, activity could be regained by making additional mutations that restored predicted base-pairings; these second site suppressors in general confirm the secondary structure derived from phylogenetic data. At several positions, our suppression data can be most readily explained by assuming non-Watson-Crick base-pairings. In addition to the requirements imposed by the secondary structure, the sequence of the intron is constrained by "negative interactions", the exclusion of particular nucleotide sequences that would form undesirable secondary structures. A comparison of genetic and phylogenetic data suggests sites that may be involved in tertiary structural interactions.

Animals↗
PubMed1989

The guanosine binding site of the Tetrahymena ribozyme.

The self-splicing Group I introns have a highly specific binding site for the substrate guanosine. Mutant versions of the Tetrahymena ribozyme have been used in combination with guanosine analogues to identify the nucleotide in the ribozyme that is primarily responsible for recognition of the guanine base.

Animals↗
PubMed1989

Bilateral duplex ectopic ureters terminating in the seminal vesicles: sonographic and CT diagnosis.

A 15-year-old boy presented with a short history of right-sided flank pain was found to have bilateral duplex renal systems with obstructed upper poles. Sonographic examination and contrast-enhanced delayed computed tomography (CT) performed at the conclusion of the excretory urography (EU) demonstrated termination of both obstructed ureters in the seminal vesicles. These noninvasive studies allowed accurate preoperative diagnosis of this abnormality.

Adolescent↗
PubMed1989

Comparison of intraperitoneal and subcutaneous insulin administration on lipids, apolipoproteins, fuel metabolites, and hormones in type I diabetes mellitus.

The relative biologic efficacy of intraperitoneal (IP) insulin administration over peripheral routes of insulin infusion for artificial delivery devices is still poorly documented. Thus, the effects of IP insulin administration have been compared with the effects of subcutaneous (SC) insulin administration upon circulating fuel metabolites, hormones and lipoproteins. In a longitudinal study, seven type I diabetic patients, aged 33 +/- 3 years, duration 16 +/- 4 years, were studied. SC intensive insulin therapy was used for 3 months, then insulin was infused IP via an implantable pump for 6 months with a similar good blood glucose control. Lipids including high density lipoprotein (HDL) cholesterol and low density lipoprotein (LDL) cholesterol, apolipoproteins A-I, A-II, and B were measured every 3 months. Although all values remained in the normal range, significant changes occurred in plasma triglycerides (63 +/- 9 SC v 88 +/- 12 mg/dL IP, P less than .05) and HDL-cholesterol (57 +/- 4 SC v 42 +/- 4 mg/dL IP, P less than .05) without concomitant changes in apolipoprotein levels. In another cross-sectional study, six of the patients consumed a standardized 400 kcal breakfast after 0.15 U/kg insulin. Eight SC insulin infused age-, glucose control- and weight-matched diabetic patients also underwent the same test using SC insulin. Six normal subjects consumed the same breakfast and served as controls. Plasma glucose, B-hydroxybutyrate, lactate, alanine, free fatty acids, free insulin and glucagon were measured for five hours after the meal. All measured parameters were comparable in both groups except free insulin and lactate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Intravesical bacillus Calmette-Guérin and second primary malignancies.

In an effort to answer the question, "Does intravesical bacillus Calmette-Guérin (BCG) therapy increase the incidence of second primary malignancies," the records of 153 patients treated with BCG for carcinoma in situ of the urinary bladder were reviewed. The weight of the available evidence suggests that intravesical BCG does not increase the incidence of second primary malignancies. While this question should be investigated, at the present time it appears that the advantage of intravesical BCG for high-risk patients with superficial bladder cancer outweighs the known disadvantages.

BCG Vaccine↗
PubMed1989

BCG in the management of superficial bladder cancer.

An overall comparison of different types of therapy for any disease is difficult. A definition of the disease, which included carcinoma in situ was not agreed upon in 1961 when thiotepa was first described. Most importantly, many series are not prospective and randomized. Response criteria have varied and have not always included cytologies. With these shortcomings in mind we have attempted to compare the various therapeutic agents. The response rate for BCG appears superior to chemotherapy for the treatment of superficial bladder cancer (59% vs 45%), for prophylaxis (77% vs 53%) and the management of carcinoma in situ (74% vs 52%). Moreover BCG also appears superior to chemotherapy for the management of prior treatment failures, particularly carcinoma in situ. In summary, this review of the literature suggests that BCG is superior, in terms of response rate, to available chemotherapy in the management of superficial bladder cancer.

Administration, Intravesical↗
PubMed1988

Absorption of buccal morphine. A comparison with slow-release morphine sulphate.

The absorption of buccal morphine was compared with that of slow-release morphine sulphate in human volunteers. Morphine concentration was assayed by high pressure liquid chromatography in serum samples obtained at intervals up to 8 hours after administration of morphine 20 mg. Similar mean maximum concentrations were obtained by either route, but the mean time to maximum concentration was longer after buccal than after enteral administration.

Absorption↗
PubMed1987

Frictional changes in force values caused by saliva substitution.

The objective of this study was to determine the magnitude of frictional force changes between several sizes of stainless steel orthodontic wires (0.018 inch round, 0.020 inch round, and 0.018 X 0.025 inch rectangular) and an edgewise bracket (0.022 X 0.028 inch slot) when an artificial saliva medium was introduced. The wires were secured in the bracket slots with a 0.010 inch polyurethane ligatures. The force values in the saliva substitute medium were compared with those produced in a dry control and in glycerin. Clinically significant differences among the environmental conditions and among the wire sizes were found. The introduction of saliva substitute provides a significant reduction in force values.

Dental Stress Analysis↗
PubMed1987

Serum morphine concentrations after buccal and intramuscular morphine administration.

1. This study compared serum concentrations of morphine after administration of a buccal tablet (25mg) with those after intramuscular injection (10mg). 2. Buccal morphine was administered to eleven healthy volunteers and intramuscular morphine was given to five preoperative surgical patients. Serum morphine concentrations were assayed by high performance liquid chromatography (h.p.l.c.) in samples taken up to 8 h after drug administration. 3. Mean maximum morphine concentrations were eight times lower after buccal administration than after intramuscular injection and occurred at a mean of 4 h later. Individual morphine concentration-time profiles showed marked interindividual variability after administration of the buccal tablet, consistent with considerable variation in tablet persistence time on the buccal mucosa.

Administration, Buccal↗
PubMed1986

Nontransferrin-bound serum iron in thalassemia and sickle cell patients.

Nontransferrin-bound iron (NTBI) was separated from transferrin bound iron (TBI) by DEAE-Sephadex-CDS filtration. TBI is eluted with Tris-NaCl buffer, NTBI that is retained on the column is eluted with citric acid. NTBI was identified in serum from thalassemia and sickle cell patients. Normal serum contained less than 6% NTBI as compared with 15-18% in patient's sera. NTBI levels were decreased significantly after 8 hr chelation with deferoxamine (DFO).

Adult↗
PubMed1986

Non-transferrin-bound iron in long-term transfusion in children with congenital anemias.

Non-transferrin-bound iron (NTBI), a potentially toxic compound, is increased in the serum of patients with iron overload and fully saturated transferrin. We found markedly elevated NTBI levels in 16 children (including nine with sickle cell disease and five with beta-thalassemia) with iron overload secondary to prolonged transfusion therapy. During iron chelation with subcutaneous desferrioxamine infusion, NTBI levels decreased to normal, but became elevated within 2 to 4 hours after discontinuation of desferrioxamine. NTBI causes hepatic and cardiac toxicity in experimental systems, but our patients lacked sufficient organ dysfunction for this association to be made. The use of continuous 24-hour chelation to maintain NTBI at low levels may prevent progressive iron toxicity in patients who first received chelation therapy at an older age or who already have evidence of cardiac damage.

Adolescent↗