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Biomedical subjects

M Hassan

Publications and source records attributed to M Hassan.

At least 163 records · Page 9Linked to original sources
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

Equity and accuracy in medical malpractice insurance pricing.

This study examines alternative classification approaches for setting medical malpractice insurance premiums. Insurers generally form risk classification categories on factors other than the physician's own loss experience. Our analysis of such classification approaches indicates different but no more categories than now used. An actuarially-fair premium-setting scheme based on the frequency and severity of the individual physician's losses would substantially penalize adverse experience. Alternatively, premiums could be set for groups of physicians, such as hospital medical staffs. Our simulations suggest that even staffs at rather small hospitals may be large enough to be experience-rated.

Actuarial Analysis↗
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↗
PubMed1989

Cellular DNA content parameters in untreated and recurrent squamous cell cancers of the head and neck.

The presence and degree of DNA aneuploidy as measured by the DNA index (DI) and the S phase fraction (SPF) were determined by flow cytometry in 294 specimens from 237 patients with untreated and recurrent squamous cell carcinomas of the head and neck (SCCHN). A descriptive analysis was performed in which the specimen DNA parameters were correlated with stage, size of primary, degree of lymph node involvement, morphological grade, and treatment status of the corresponding patients. Approximately 70% of the previously untreated specimens contained DNA aneuploid populations (DI greater than 1.10) and three quarters had SPF that were above 15%. There was a strong, direct association between DI and SPF (P less than 0.001). There was no correlation of the presence or degree of DNA aneuploidy with the stage of the tumor or the size of the primary or conventional morphological grade of the tumor. Specimens from patients with recurrent tumors and untreated patients with N3 lymph nodes had significantly lower rates of DNA aneuploidy and mean DI. Serial determinations of DNA aneuploidy in patients with SCCHN undergoing cytotoxic therapy are ongoing and may prove useful in the identification and understanding of resistance and response in this tumor.

Adult↗
PubMed1989

Pharmacokinetic and metabolic studies of high-dose busulphan in adults.

The pharmacokinetics of high-dose busulphan was studied in adult patients with acute myeloblastic leukaemia after oral doses of 1 mg.kg-1 every 6 h for 4 days. The mean steady-state plasma concentration was 1080 ng/ml-1 during the treatment. Individual steady-state concentrations after the last dose on average were 32% lower than those predicted from total AUC measurements following the first dose. Mean elimination half-life in plasma was 2.3 h after the last dose and 3.4 h after the first dose which suggests that busulfan may increase its own metabolic rate on repeated treatment. The cerebrospinal fluid/plasma concentration ratio of busulphan was 1.3. Busulphan showed insignificant protein binding in plasma (7.4%). About 2% of the dose was excreted unchanged in the urine. For the first time sulpholane, 3-hydroxysulpholane and tetrahydrothiophene 1-oxide were identified as urinary metabolites of busulphan in man.

Adult↗
PubMed1989

Nondysenteric intestinal amebiasis. Colonic morphology and search for Entamoeba histolytica adherence and invasion.

There is controversy regarding the presence of colonic mucosal abnormalities or mucosal invasion by Entamoeba histolytica in patients with "nondysenteric intestinal amebiasis." To determine the role of E. histolytica in causing symptoms and mucosal changes and to detect if mucosal invasion by E. histolytica is present in nondynsenteric intestinal amebiasis, we evaluated 24 E. histolytica-infected patients (stool microscopy positive for E. histolytica) and 12 noninfected controls who presented with chronic gastrointestinal symptoms, but without dysentery, to a clinic in Calcutta. The colonic mucosa was evaluated at colonoscopy, and mucosal biopsies obtained from the cecum, sigmoid colon, and rectum were evaluated by light microscopy, indirect immunofluorescence microscopy, and scanning electron microscopy. At colonoscopy mucosal ulcerations were absent in all the controls and all except one of the E. histolytica-infected patients. E. histolytica trophozoites or cysts were not seen in the lamina propria or on the luminal surface in any infected patient by light and immunofluorescence microscopy. On scanning electron microscopy, structures that resembled rounded E. histolytica trophozoites were seen on the luminal surface in two of 19 cecal specimens from the infected patients. Moderate or severe mucosal inflammation was frequent on light microscopy in both the E. histolytica-infected patients and the noninfected controls with the cecum involved in two thirds of both groups. Antibodies to E. histolytica were detected in serum of 25% of study patients and 58% of controls. Mucosal inflammation did not correlate with stool positivity for E. histolytica or seropositivity for ameba antibody.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Synthesis of [11C]sodium thiocyanate for in vivo studies of anion kinetics using positron emission tomography (PET).

Sodium thiocyanate (NaSCN) was labelled with carbon-11 for in vivo studies of anion kinetics using positron emission tomography (PET). The synthesis was complete in 35 min from end of bombardment using [11C]ammonium cyanide as the labelled precursor. [11C]NaSCN was produced by the reaction of [11C]sodium cyanide with elemental sulfur and subsequently separated by semi-preparative high performance liquid chromatography (HPLC). Radiochemical yields (isolated) were of the order of 25%. The specific activity was 18 GBq/mmol and the radiochemical purity better than 99%. A PET study performed in a healthy volunteer showed distribution of [11C]SCN- to areas corresponding to cortical fluid spaces known to be accessible to inorganic ions such as Cl-. An accumulation of the tracer was observed during the 70 min investigation, indicating at least three compartments of distribution.

Anions↗
PubMed1989

Ultrastructural and hormonal metabolic studies of rat liver maintained in vitro by perfusion at 30 degrees C and 37 degrees C: a time course study by TEM, SEM and RIA.

Isolated rat liver perfusion system has been extensively used for metabolic and functional studies. Results derived from the application of this system may reflect true biochemical changes but they may also be associated with some structural changes. This study was undertaken to correlate the cytological changes and functional integrity of isolated rat liver perfused in vitro at normal physiological temperature (37 degrees C) and 30 degrees C, using a non-recirculating system. The livers were perfused for 3 hours with modified Ham's F10 culture medium supplemented with thyroxine hormone (T4). The hepatocyte structural integrity was studied by light microscopy, transmission and scanning electron microscopy. The triiodothyronine (T3) and T4 hormones in the perfusion medium and the effluent fractions were assessed by radioimmunoassay. The livers perfused at 30 degrees C remained morphologically intact at the ultrastructural level for 3 hours whilst at 37 degrees C, hepatocytes in the centrilobular zone exhibited marked structural alterations. The percentage of T4 uptake was significantly higher (P less than 0.01) in livers perfused at 30 degrees C (50.8 +/- 7.7% vs 38 +/- 7.7%, 37 degrees C), but the net T3 output (3.16 +/- 1.04 micrograms) and the conversion of T4 to T3 (4 +/- 0.62%) were significantly higher (P less than 0.001) in livers perfused at 37 degrees C in comparison to livers perfused at 30 degrees C (1.61 +/- 0.84 micrograms and 1.68 +/- 0.76%, respectively). In conclusion, at 30 degrees C the hepatic T4 uptake is not inhibited, but the rate of T4 to T3 conversion has decreased, additionally the livers remain morphologically well preserved throughout the experimental period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Cerebrospinal fluid and plasma concentrations of busulfan during high-dose therapy.

A patient with acute myeloblastic leukemia received high-dose busulfan (1 mg/kg by mouth every 6 h for 4 days) as myelo-ablative therapy for autologous bone marrow transplantation. Rapid entry of busulfan into the cerebrospinal fluid (CSF) was observed. Plasma and CSF concentrations of busulfan were comparable during the 4 days of treatment. The elimination half-lives of busulfan in plasma and CSF were 2.6 h and 2.8 h respectively during the first 12 h after the last dose.

Bone Marrow Transplantation↗