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Biomedical subjects

A Said

Publications and source records attributed to A Said.

At least 19 recordsLinked to original sources
PubMed2006

A cryogenically stabilized meV-monochromator for hard X-rays.

The design and performance results for a cryogenically stabilized high-resolution monochromator for 23.880 keV (lambda = 52 pm) X-rays are presented. The four-crystal-reflection monochromator is suitable for nuclear resonant scattering measurements from 119Sn compounds using synchrotron radiation. The design includes a low-vibration cryostat that maintains two of the four crystal reflections at a temperature where the coefficient for thermal expansion of the crystalline material (silicon) vanishes. Test results demonstrate a 1.3 meV bandwidth with negligible broadening due to vibrations and a spectral efficiency of 37% when used with an undulator source.

Journal Article↗
PubMed2006

Excitations of lithium ammonia complexes studied by inelastic x-ray scattering.

We have carried out high-resolution inelastic x-ray scattering measurements of the excitations of lithium dissolved in ammonia. The incident x-ray energy was 21.6 keV and the resolution was about 2 meV. Several different excitations are observed in the energy range of 0-60 meV (0-500 cm(-1)). In addition to acoustic phonons at low energies, we see excitations that are associated with vibrations of Li(NH3)4+ complexes. We examined these excitations as a function of momentum transfer, lithium concentration, temperature, and state of the system (solid versus liquid). Data are compared with Hartree-Fock and density-functional theory calculations of the excitations of this complex, which agree well with the measured excitation energies.

Journal Article↗
PubMed2005

Optimization of the safety and efficacy of interferon beta 1b and azathioprine combination therapy in multiple sclerosis.

We conducted an open-label pilot clinical trial to evaluate the safety and efficacy of adding oral azathioprine to the treatment regimen of 15 multiple sclerosis patients breaking through monotherapy with interferon beta-1b. There were no serious adverse events. Gastrointestinal side effects and leukopenia were the most common adverse events and limited dose escalation. There was a 65% reduction in the number of gadolinium-enhanced magnetic resonance imaging (MRI) lesions on combination therapy compared to the baseline values (P =0.003). A total WBC count less than 4800/mm3 was the best predictor of MRI response.

Adjuvants, Immunologic↗
PubMed2002

Electronic interactions in the expanded metal compound Li-NH3.

Inelastic x-ray scattering was used to measure the plasmon as a function of electron density in liquid lithium ammonia as well as the low temperature solid phase. As the electronic density is lowered, electronic correlation effects cause the random-phase approximation (RPA) to break down, requiring more advanced theoretical treatments. The deviation from RPA becomes greatest at the lowest electronic densities. We also see evidence for decreased electronic screening as shown by an increase in the strength of the pseudopotential at lower concentrations. Plasmon behavior in the solid is similar to that of the heavier alkali metals, but surprisingly different than in the liquid.

Journal Article↗
PubMed2002

[Salmonella identification after incubation in the soil].

We have tried to study the fate of Salmonella strains in soil. We have looked at their biochemical modifications during their evolution to dormant state and during their reviviscence. The beta galactosidase which is negative in the parent strain became positive after two weeks of cells starvation in soil. Stressed cells became able to produce acetoin. Some stressed cells did not produce the lysine decarboxylase, which is positive in parent cells. These modifications are reversible and depend on cultural conditions. Incubation of stressed cells in nutrient broth for more than four weeks helped them to reverse to normal forms. Simultaneous search for atypical Salmonella was done in dissect sludge of a domestic wastewater treatment plant and in soil irrigated with treated water. Atypical strains of Salmonella are found. We have seen that, after incubation in nutrient broth for more than four weeks, atypical strains characters evolved generally to their parental characters. All modifications of Salmonella in soil samples can make their identification very difficult and perhaps impossible.

Bacteriological Techniques↗
PubMed1999

Screening for hepatocellular carcinoma in patients with cirrhosis in the United States: results of a national survey.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the dreaded complications of cirrhosis. Although there are no randomized controlled studies showing improved survival with screening, patients with cirrhosis are screened for HCC. Little is known about the practice of HCC screening in the United States. Our aim was to describe the practice of HCC screening in patients with cirrhosis in the United States. METHODS: In March 1998, we mailed a standard questionnaire to 1021 physician members of the American Association of Study for Liver Diseases and the same questionnaire was re-sent to nonrespondents 4 weeks later. RESULTS: We received a response from 554 members (54%). After excluding those not involved in active adult patient care, 473 responses were eligible for analysis. Eighty-four percent of the respondents routinely screened patients with cirrhosis for HCC (screening respondents). Nearly half of the screening respondents limited the HCC screening to patients with high-risk etiologies such as hepatitis B or C or hemochromatosis. Although alpha-fetoprotein (99.7%) and ultrasound (93%) were the two most frequently used screening methods, a sizable proportion of the screening respondents (25%) used abdominal computed tomography for routine screening. On multivariate analysis, the following variables predicted screening for HCC by the respondents: seeing more than one new cirrhotic per week (odds ratio [OR]: 5.4, 95% confidence interval [CI]: 2.5-11.7); practicing for < 10 yr (OR: 4.0, 95% CI: 1.2-13.4); an opinion that screening is cost-effective (OR: 6.4, 95% CI: 1.6-25); an opinion that screening prolongs survival (OR: 5.7, 95% CI: 1.8-17.9); and an opinion that not screening poses malpractice liability (OR: 9.3, 95% CI: 4.2-20.8). CONCLUSIONS: The majority of respondents routinely screen patients with cirrhosis for HCC. Approximately half of the screening respondents limit their screening to only patients with high-risk etiologies. On multivariate analysis, several variables predicted screening for HCC by the respondents.

Adult↗
PubMed1999

Screening for hepatocellular carcinoma in patients with advanced cirrhosis.

OBJECTIVE: Most available data on screening for hepatocellular carcinoma (HCC) in patients with cirrhosis originate from Asia and Europe. These data may not be applicable to patients from the United States because of geographic variation in the underlying etiology and other factors. Our aim was to assess the risk of HCC in U.S. patients with cirrhosis undergoing standardized screening. METHODS: All cirrhotic patients evaluated for liver transplantation at our institution from January 1, 1994-December 31, 1997 were included in this study. The screening strategy included initial screening, which was offered to all patients and consisted of alpha-fetoprotein (AFP), abdominal ultrasound, and computed tomography (CT) scan, and extended screening, which was performed only on transplant-eligible patients and consisted of semiannual AFP and ultrasound. RESULTS: During the study period, 285 patients with cirrhosis were evaluated for transplantation and underwent initial screening. Of these, 166 were eligible for transplantation and underwent extended screening during a median follow-up of 15 months (range 6-42 months). Twenty-seven HCC were found, 22 during initial screening and five during extended screening. The cancer-free proportions of the cohort who underwent extended screening at 1, 2, and 3.5 yr were 98.6% +/- 1.4%, 96.4 +/- 1.8%, and 77.1% +/- 1.7%, respectively (mean +/- SE). Hepatitis C, either alone or in part, was the etiology in 63% of patients with HCC. The sensitivity of CT scan (88%) was significantly higher than AFP >20 ng/ml (62%) and ultrasound (59%) for detecting HCC (p < 0.001). CONCLUSIONS: In patients with established cirrhosis, the risk of detecting HCC is maximal at the baseline screening (7%). Hepatitis C was the most common etiology for cirrhosis in study. In U.S. patients with established cirrhosis, CT scan exhibited higher sensitivity for detecting HCC than ultrasound or AFP.

Adult↗
PubMed1996

Lipophilicity determination of psoralens used in therapy through solubility and partitioning: comparison of theoretical and experimental approaches.

The aim of this study was to determine and to compare experimental and theoretical solubilities (S) as well as partition coefficients (PC) in an octanol/water system of psoralen (P), 8-methoxypsoralen (8-MOP), 5-methoxypsoralen (5-MOP) and 4,5',8-trimethylpsoralen (TMP). For each psoralen, experimental results were performed in triplicate with a spectrofluorimetric technique. The measurements were achieved 10 times for each solution. The obtained order of the solubilities in pure octanol was 5-MOP approximately TMP > P > 8-MOP, while in water-saturated octanol it was expressed as follows: TMP approximately 5-MOP > P > 8-MOP. However, the following order was found for hydrophobicity: TMP > 5-MOP > 8-MOP > P. The solubility ratios (SR) in pure octanol and water were assessed (mean +/- SD): 3.13 +/- 0.01 (P), 2.60 +/- 0.01 (8-MOP), 3.75 +/- 0.01 (5-MOP), and 5.11 +/- 0.01 (TMP). In saturated phases, they were 3.27 +/- 0.01, 2.63 +/- 0.01, 3.85 +/- 0.01, and 5.32 +/- 0.01, respectively. The PCs were determined with low concentrations according to the Dearden and Bresnen32 method and they were 1.67 +/- 0.01, 1.93 +/- 0.01, 2.00 +/- 0.01, and 3.14 +/- 0.01, respectively. Solubility parameters (delta), in Hildebrand unit (H) or in (cal/cm3)1/2, were evaluated. They confirmed the polarity of psoralens, previously expressed through the PC, although the positional isomers (5-MOP and 8-MOP) revealed no difference. Hildebrand's approach to the solubility of regular solutions and Yalkowsky's concept of the solubility of nonelectrolytes and weak electrolytes in an octanol/water system permitted a comparison of the theoretical and experimental results. The perspective of this work is to use the physicochemical properties of the psoralens in practice for insuring convenient experimental assays and the prediction, in vitro, of the percutaneous absorption of these compounds.

5-Methoxypsoralen↗
PubMed1992

Pregnancy-associated hypertension in Maputo. A study on maternal characteristics and perinatal outcome in 1275 consecutive cases.

A total of 1275 consecutive cases of pregnancy-associated hypertension were registered in the Maputo Central Hospital (corresponding to 2.9% of a total of 43,794 city parturients). In the hypertensive and in the reference populations the following prevalence figures were registered, respectively: age below 25 years, 52% and 23% (P < 0.0005); nulliparity, 33% and 19% (P < 0.0005); twin pregnancies, 3.9% and 1.7% (P < 0.0005); stillbirths, 5.7% and 2.3% (P < 0.0005); and low birthweight (LBW), 22.9% and 10.7% (P < 0.0005). In the hypertensive population the prevalence of LBW newborns was 20.1% in the liveborn group, while it was 68.4% in the stillborn group (P < 0.0005). In the ongoing perinatal audit it was found useful to review hypertensive women separately, in order to assess current routines in cases of pregnancy hypertension.

Adult↗
PubMed1992

Treatment of lower respiratory tract infections with sultamicillin.

Oral tablets containing 375 mg sultamicillin were used to treat 30 adult patients of either sex suffering from lower respiratory tract infections. The dose used was one tablet every 12 h for 22 cases and one tablet every 8 h for eight cases. The duration of therapy varied between 5 and 14 days (mean 8.6 days). The therapeutic response was rated as cure in 23 (76.6%) patients, with complete disappearance of pretreatment signs and symptoms, and as improvement in seven (23.3%) patients, with amelioration of the pretreatment manifestations. All 52 microorganisms isolated before treatment were eradicated. No adverse effects were reported in 25 (83.3%) patients, whereas the remaining five (16.7%) patients reported mild loose stools with normal bowel motion. There were no abnormal changes in blood count and liver and renal functions following sultamicillin treatment.

Acute Disease↗
PubMed1992

Sultamicillin in the treatment of obstetric and gynaecological infections.

A total of 40 adult females were studied suffering from different obstetric and gynaecological infections. In 30 patients two 375 mg sultamicillin tablets were taken twice daily, whereas 10 patients received one 375 mg sultamicillin tablet twice daily. The duration of treatment ranged from 5 to 12 days, with a mean of 6.6 days. Cure or improvement was reported in 35 (87.5%) cases, whereas five (12.5%) patients did not respond to therapy. Of the 61 pathogens isolated before treatment, 56 (91.8%) were eradicated. Clinical tolerability of the therapy was excellent, with no adverse effects being observed in any of the studied patients. The absence of significant differences between the mean values of blood count, hepatic and renal function tests performed before and after treatment confirmed the safety of treatment. It is concluded that sultamicillin is a suitable and useful additional antibiotic therapy for the treatment of obstetric and gynaecological bacterial infections.

Administration, Oral↗
PubMed1991

Anaesthetic-induced ventricular tachyarrhythmia in Jervell and Lange-Nielsen syndrome.

A four-year-old deaf girl with a history of convulsions developed polymorphous ventricular tachycardia during induction of anaesthesia. The arrhythmia reverted to sinus rhythm spontaneously. Post-anaesthetic ECG showed marked prolongation of the QTc interval (570-690 msec). Deafness and prolonged QTc interval in association with microcytic-hypochromic anaemia confirmed the diagnosis of the Jervell and Lange-Nielsen syndrome. This case report highlights the potentially lethal complication of halothane anaesthesia in patients with long QTc interval syndrome.

Anesthesia, Inhalation↗
PubMed1991

Intramuscular sulbactam/ampicillin combination therapy in gynaecological and obstetric bacterial infections.

Estimates were carried out on the clinical and bacteriological efficacy of an intramuscular combination of sulbactam/ampicillin, together with an assessment of its tolerability and safety in the treatment of gynaecological and obstetric infections. A total of 30 women with pelvic inflammatory disease, wound infections, vaginitis and puerperal sepsis received an intramuscular combination of sulbactam/ampicillin in a total daily dose of 1.5 g for between 3 and 7 days. Clinical cure and improvement were achieved in 27 (90%) cases but there was no response in three (10%) cases. No side-effects were seen in 29 (97%) cases, whereas tolerable local injection site pain was reported in one case. The safety of the sulbactam/ampicillin antibiotic combination was evident in all the cases studied, as there was no significant difference between the means of laboratory tests before and after therapy of blood and renal measures.

Adult↗
PubMed1990

Inhibition of the growth of enteropathogenic bacilli by bacteriocins produced by micro-organisms from the sediment of wells.

The bacterial flora of the sediment of 20 wells of water for human consumption in the rural area of the VII Region in Chile was examined. Fourteen strains of bacteria, from different wells, produced bacteriocins which inhibited the growth of Salmonella typhi, Salm. typhimurium, Shigella sonnei and enterotoxigenic Escherichia coli. About 50% of these strains contained plasmids of different molecular weight and a large number of these codified for bacteriocins. The results suggest what is required to implement an efficient, simple and economical biological system for the purification or control of the number of enteropathogenic bacilli of well water in the rural area.

Bacteriocins↗
PubMed1989

[Complete inhibition of cyclic transmission by immunization against Plasmodium berghei Anka ookinetes].

An antiserum raised against P. berghei Anka ookinetes binds specifically to ookinetes and zygotes surface as assessed by indirect immunofluorescence. The transmission blocking activity of this serum was assessed by feeding mosquitoes on immunized mice. A serum showing an antibody titer of 1/320 reached after 6 immunizations completely blocks ookinetes development. This immune serum might be used to screen P. berghei genomic or cDNA library in order to identify or clone sequences involved in the process of gametocyte infectivity.

Animals↗