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Biomedical subjects

M Hassan

Publications and source records attributed to M Hassan.

At least 19 recordsLinked to original sources
PubMed1992

In vivo distribution of [11C]-busulfan in cynomolgus monkey and in the brain of a human patient.

The in vivo distribution of the antileukemic agent busulfan labeled with the positron-emitting radionuclide carbon 11 was investigated in cynomolgus monkeys and in a human patient using positron emission tomography. After i.v. injection of the radiotracer, its regional uptake was monitored for about 1 h in the monkey's body and, in a separate experiment, in the monkey's brain. The concentration of radioactivity in the liver, which showed the highest levels of all the organs scanned, increased throughout the experiment and was 9-fold that in the brain at the end of the experiment. [11C]-Busulfan rapidly crossed the blood-brain barrier. The radioactivity peaked in both the cortex and the white matter showing a ratio of 1.25, at 3 min but declined quickly to yield a ratio of approximately 1 after 30 min. In the human brain, radioactivity in the cerebellum, cortex, and white matter reached a maximum within 5 min showing a cortex:white matter ratio of 1.6. The activity in the cortex declined to yield a ratio of 1 within 30 min. Of the delivered dose, 20% penetrated into the brain.

Adult↗
PubMed1992

Contribution of MR in the diagnosis of 'occult' posterior laryngeal cleft.

This paper reports three cases of 'occult' submucous posterior laryngeal cleft in which MR examination has visualized the deficiency of the posterior cricoid lamina. Laryngeal cleft is an uncommon anomaly, and its clinical and endoscopic diagnosis is always difficult. To our knowledge, the role of MR in this diagnosis has not yet been emphasized.

Cricoid Cartilage↗
PubMed1992

Effectiveness of the daily record review at the medical emergency room department in a French teaching children's hospital.

We evaluate the effectiveness of the daily record review (DRR) of 4393 ambulatory medical patients seen at the emergency room department of a teaching pediatric hospital in Paris between 8th January and 11 March 1991. For these patients, 137 potential quality problems were found, 117 of them remaining after discussion with the junior. For 80 of the 117 confirmed problems (68.4%), the reviewing senior estimated that sufficient advice had been given to the child's usual caretaker or health care provider and (or) the children returned to seek medical advice when indicated. Experts proved the procedure to be reliable: they detected a problem for 36% of the cases with potential quality problems and for only 2% of a sample of control records considered without potential quality problems after the DRR.

Emergency Service, Hospital↗
PubMed1992

On the bioavailability of oral and subcutaneous 2-chloro-2'-deoxyadenosine in humans: alternative routes of administration.

PURPOSE: The antimetabolite 2-chloro-2'-deoxyadenosine (CdA) is a promising alternative to alkylating agents for the treatment of lymphoproliferative disorders. Its use, however, is hampered by the need for intravenous (IV) administration. The aim of the present study was to determine the bioavailability of subcutaneously (SC) and orally administered CdA, and to establish an oral dose of CdA that could supersede IV administration. PATIENTS AND METHODS: A previously developed high-performance liquid chromatography method was used for the determination of plasma CdA concentrations in 13 patients. Ten patients were treated on alternate days with 0.14 mg/kg/d CdA as a 2-hour IV infusion or by a SC injection. Three of these patients were also given 0.14 mg/kg CdA orally in enteric-coated capsules. Ten patients were administered CdA orally that was dissolved in phosphate-buffered saline (PBS) after treatment with 20 mg omeprazole 1 and 6 hours before the administration of CdA. RESULTS: The bioavailability of SC CdA was 102% +/- 28% (mean +/- SD), and the bioavailability of CdA administered in enteric-coated capsules was 19%, 24%, and 60%. In the three patients who were given 0.14 mg/kg orally dissolved in PBS, the bioavailability was 48% +/- 8%, whereas in the seven patients who received 0.28 mg/kg, the bioavailability was 55% +/- 17%. In the 10 patients who were treated with the CdA solution orally, the coefficients of variation of the areas under the curve (AUCs) after oral and IV administration were similar. Thus, oral administration did not add to the interindividual variability. CONCLUSIONS: We conclude that orally administered CdA can supersede IV infusion if the dose is doubled. SC administration gives a high peak concentration of short duration with an AUC identical to that of IV infusion. Thus, SC injection can also be used as an alternative to IV infusion.

Administration, Oral↗
PubMed1992

[Antibiotic therapy of infections in patients on dialysis].

The results obtained in treating infections in 53 patients involved in a chronic dialysis-transplantation program are reported. Higher susceptibility to infections and reduced immune functions were observed in dialyzed patients. The problem of the occurrence rate of individual infections was analyzed and infections of the respiratory system, particularly bronchopneumonia, were found to be predominant. No patient died of infection; in two patients the prescribed antibiotic of first choice had to be changed; positive clinical and laboratory effect was recorded in 51 of the 53 patients treated, and after change of the antibiotic in all the patients. Particular regimens of individual antibiotics in dialyzed patients are given along with the dialyzability of the drugs. The best results were obtained with ofloxacin and doxycycline of Czecho-Slovak make in monotherapy, in combined treatment gentamycin an amikacin with cefamezin or with cefotaxim proved to be most effective. Of the 45 pathogenic agents isolated, Staphylococcus aureus, Klebsiella spp, and Acinetobacter lwoffi, which have a good sensitivity to antibiotics, had the highest occurrence rates. (Tab. 4, Ref. 6.).

Anti-Bacterial Agents↗
PubMed1991

Pharmacokinetics of high-dose busulphan in relation to age and chronopharmacology.

Busulphan levels in plasma were measured in 27 patients during conditioning therapy (1 mg/kg x 4 for 4 days) before bone marrow transplantation. The mean minimal concentration found in children aged less than 5 years (237 ng ml-1) was lower than that observed in adults or older children (607 and 573 ng ml-1, respectively). The AUC for the last dose was significantly lower in young children (2.315 h ng ml-1) than in adults or older children (6,134 and 5,937 h ng ml-1, respectively). The elimination half-life for the last dose in young children was shorter (2.05 h) than that in either adults (2.59 h) or older children (2.79 h). When the AUC was normalized for body surface area, the difference between young children and the other groups was smaller but remained statistically significant. The total body clearance was significantly higher in young children (7.3 ml min-1 kg-1) as compared with both older children and adults (3.02 and 2.7 ml min-1 kg-1, respectively). The plasma levels of busulphan showed circadian rhythmicity, especially in young children. The concentration measured during the night in some patients was up to 3-fold that observed during daytime. We conclude that the busulphan dosage for children must be reconsidered and that further studies are urgently needed to develop an optimal therapy.

Adolescent↗
PubMed1991

Laryngeal ultrasonography in infants and children: pathological findings.

In a previous paper, the normal sonographic anatomy of the larynx has been described. The pathological findings of this method, its advantages and its drawbacks are now discussed and compared to endoscopy and plain films. It appears to be a very interesting method for functional disorders and space-occupying lesions.

Adolescent↗
PubMed1991

11C-labeling of busulphan.

Busulphan [1,4-bis(methanesulfonoxy)butane], an alkylating agent used in the treatment of chronic myelocytic leukemia, was labeled with the positron-emitting radionuclide carbon-11 in a four-step synthetic procedure [1-11C]4-Hydroxybutyronitrile was obtained in 60-70% yield by the reaction of [11C]cyanide with 3-bromopropanol. The nitrile was hydrolysed to [1-11C]gamma-butyrolactone (80-90% yield) with sulfuric acid. Solid phase extraction was used to isolate the lactone and change the solvent before reduction to [1-11C]1,4-butanediol. Dimesylation of the diol with methanesulfonyl chloride in dichloromethane/pyridine yielded [1-11C]busulphan with conversions in the order of 30-35%. The total time of synthesis, including HPLC purification, was 65-75 min from the end-of-trapping of [11C]ammonium cyanide. The decay-corrected isolated yield of no-carrier-added [11C]busulphan was 4-7% and the radiochemical purity was better than 99%.

Busulfan↗
PubMed1991

[Balloon dilatation of tracheobronchial stenoses in children. Apropos of 4 cases].

Long-lasting tracheal tubing in newborns and infants, associated with repeated tracheobronchial aspiration, is sometimes complicated by tracheal and/or bronchial stenoses. Many therapeutic methods have been described to treat this condition: use of dilatators, laser, surgery, insertion of prosthetic material. Dilatation with an angioplasty balloon has been recently described for the treatment of various stenoses. The authors report about 3 cases of acquired tracheobronchial stenosis which were successfully treated with this method, and 1 case of complex tracheal stenosis (with a double inflammatory and congenital nature) which required both dilatation and surgery. The technique is described. There is no morbidity and no mortality in this non-randomized series. Balloon dilatation is a simple and effective method, which may be proposed as a first-intention treatment for acquired tracheobronchial stenosis in newborns and infants.

Bronchial Diseases↗
PubMed1991

How profitable is medical malpractice insurance?

High medical malpractice insurance premiums charged to physicians have created the perception of a crisis. Some researchers have expressed the concern that medical malpractice insurance companies are making excessive profits. In this paper I compute the actual and allowable normal underwriting profit rates in medical malpractice, as well as in other liability lines, for six large insurance companies. These allowable, normal profit rates are then compared with actual profit rates to evaluate the relative profitability of each line of insurance. Data from 1978 through 1986 show that medical malpractice insurance ranked medium in underwriting profitability compared with other lines of insurance, and during 1985-86 it was the least profitable insurance business.

Actuarial Analysis↗
PubMed1990

Laryngeal ultrasonography in infants and children: anatomical correlation with fetal preparations.

Normal sonographic anatomy of the larynx in children was established by studying 40 healthy children and 3 fetuses. The normal anatomy is described on transverse sonograms passing at level of the ventricular bands, the true vocal cords and the subglottis and the interpretation of the sonographic aspect of the larynx is given. Ultrasound of the larynx seems to provide a good analysis of cartilaginous and endolaryngeal structures and can also show the dynamic aspect of the larynx. A pathological case is described as an illustration of the potentialities of this new way of imaging the larynx.

Adolescent↗
PubMed1990

[Contribution of sectional imaging, echography and MRI, for the diagnosis of splenic infarction in Osler endocarditis. Apropos of a case].

A case of symptomatic splenic infarct in an 11 year-old girl suffering from bacterial endocarditis is reported; this occurrence is a rare and serious condition in this disease. The diagnosis of haemorrhagic splenic infarct was suggested by ultrasonography and confirmed by MRI. No splenic abscess developed and this was correlated to a rapid improvement of the clinical state following an antibiotic treatment only. The authors discuss the role of sonography and MR in the etiologic diagnosis of splenic involvement in patients suffering from bacterial endocarditis.

Child↗
PubMed1989

Medical malpractice experience of physicians. Predictable or haphazard?

This study uses a large malpractice database from Florida to assess the concentration of losses among physicians, predictability of claims experience, characteristics of physicians with favorable vs unfavorable experience, and effects of claims experience on physicians' practice decisions and on actions taken by the state's licensing board. Most payments by insurers involved a comparatively small number of physicians. Physicians with relatively prestigious credentials had no better, and on some indicators, worse claims experience. If anything, physicians with adverse claims experience were less likely to make subsequent changes in their practice, such as quitting practice or moving to another state. Physicians with very poor claims histories were more likely to have complaints filed against them with the Florida licensing board, but the sanctions against physicians with either poor or excellent histories were not severe. Physicians with adverse claims experience from incidents that arose between 1975 and 1980 had appreciably worse claims experience from incidents that arose during 1981 to 1983.

Anesthesiology↗
PubMed1989

The correlation of specific variables of tumor differentiation with response rate and survival in patients with advanced head and neck cancer treated with induction chemotherapy.

The authors have reported previously that conventionally defined grades of tumor morphology do not correlate with tumor response or survival in advanced squamous cell cancers of the head and neck (SCCHN) treated with cisplatinum combination induction therapy. This lack of correlation may be the result of the imprecision and subjectiveness of the conventional grade determination. To examine this possibility, response and survival were correlated with individual parameters of morphologic differentiation in 136 patients with advanced, untreated SCCHN. A multi-variable analysis of degree of keratinization, number of mitotic figures per high powered field, degree of nuclear differentiation, presence of vascular invasion, intensity of inflammatory response, and invasion pattern of the cancer was performed. The grade of each variable was weighted by assigning a score from 1 to 4, with 1 representing the most differentiated and 4 the least. The cumulative score of each specimen was tallied and assigned to one of three groups, less than 12, 12 to 18, and greater than 18, analogous to the conventional grades of well, moderately, and poorly differentiated, respectively. No correlation between the grade of individual morphologic variables and response to chemotherapy was demonstrated, or between tumor response and cumulative score groups. There was no correlation of the grade of individual morphologic variables or cumulative score groups with survival. Only the survival of patients achieving a complete response to chemotherapy was correlated with the cumulative score groups: 2-year survivals of 84%, 70%, and 46% for less than 12, 12 to 18, and greater than 18, respectively. Multi-parameter analysis of individual features of tumor differentiation is not superior to conventional morphologic analysis in predicting response to chemotherapy or survival in patients with advanced SCCHN.

Adult↗