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PubMed1978

Physical and nutritional factors in gel culture of mammalian cells.

The growth of human glioma cells, cultured as spherical colonies in agarose gel, stopped after about 10 days for both large and small colonies apparently due to an increased osmolality in the gel. When osmolality was kept under control by addition of distilled water, growth continued. However, a continuous increase in the population-doubling period, similar for both large and small colonies, then was observed. The increase persisted although excess amounts of nutrition were added. When the cells were cultured in liquid suspension above a thin layer of agarose gel and most of the medium was repeatedly changed, the colonies continued to grow beyond the limits in gel cultured. HeLa and hamster embryonic lung cell colonies showed a growth pattern in agarose gel similar to the glioma cells. The results imply that the osmolality must be kept under precise control to prevent growth inhibition. However, it seems difficult to ascertain optimal growth in gel culture for more than about 2 weeks probably because of the accumulation of toxic products.

Animals↗

PubMed2002

Stereotactic synchrotron microbeam radiotherapy.

Highly collimated synchrotron x-ray beams with high fluence rate may be used in stereotactic radiotherapy of brain tumours. Several monochromatic x-ray beams having uniform microscopic thickness ie (microplanar beams) are directed to the center of the tumour from varying directions, delivering lethal dose to the target volume while sparing normal cells. This proposed technique takes advantage of the hypothesised repair mechanism of capillaries between closely spaced microplanar beam zones. The sharply dropping lateral dose profile of a microplanar beam provides low scattered dose to the off-target interbeam volume. In close proximity to the target volume, relatively high secondary electron doses close to the edge of the beams overlap and produce a high dose region between angled beams. This allows precise targeting and prevents gradual blurring of the higher and lower dose margins in the target volume. The advantages of stereotactic microplanar beam radiotherapy will be lost as the dose between microplanar beams exceeds the tolerance dose of the dose limiting tissues. Therefore to minimize the risks of delayed radiation damage it is essential to optimize the interbeam doses inside a human head phantom. The EGS4 Monte Carlo code is used to calculate the lateral dose profiles and depth dose of a 100 keV single microplanar beam in the phantom. A general equation for absorbed dose as a function of depth and lateral distances is derived for the single beam. Several microplanar beams are directed into the target volume at the center of the phantom. Using the equation, maximum dose on the beam axis (primary + total scattered dose) and the minimum interbeam dose (total scattered dose) are calculated at different depths and an isodose map of the phantom is obtained. A stereotactic microplanar beam radiotherapy model is proposed for a 10 mm diameter (approximately spherical) tumour at the center of the phantom.

Brain Neoplasms↗

PubMed1996

Port-site metastases of adenocarcinoma of the fallopian tube after laparoscopically assisted vaginal hysterectomy and salpingo-oophorectomy.

Port-site metastases following laparoscopic surgery for cancer constitute an emerging problem. We report a case of cutaneous metastasis at a port site following laparoscopically assisted vaginal hysterectomy and salpingo-oophorectomy for unsuspected adenocarcinoma of the fallopian tube. This complication occurred 7 months postoperatively and was treated with resection. A single site was involved. Possible etiologies are implantation from "contaminated" instruments or dissemination of tumor cells by the positive-pressure pneumoperitoneum. Preventive measures include precise and clean surgical technique, the use of a nonporous bag, postoperative trocar-site excision or irradiation, and conversion to laparotomy either intra- or postoperatively.

Adenocarcinoma↗

PubMed1996

Gas embolism during laparoscopy: a report of seven cases in patients with previous abdominal surgical history.

The use of laparoscopic surgery has grown considerably, and the occurrence of some accidents, albeit rare, is now reported. Among them, gas embolism can induce a bad postoperative outcome. We report seven cases of carbon dioxide embolism (CO2) during laparoscopic surgery. In the seven cases gas embolism occurred during insufflation or a few minutes later. All the patients had a previous abdominal or pelvic surgical history. Five patients presented cardiac bradycardia or arrhythmia. Cardiovascular collapse or cyanosis was the first manifestation in three cases. Sudden bilateral mydriasis was the earliest neurologic sign, present in five cases. Finally, the gas embolism complication was lethal in two cases. In summary, this study strongly stresses the need for precise rules of prevention of gas embolism, and close monitoring of cardiac rhythm during insufflation of carbon dioxide. The patients who had previous surgery should be considered as a risk population.

Adult↗

PubMed1982

A method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry.

A simple but reliable method for the routine determination of aluminium in serum and water by flameless atomic absorption spectrometry is described. No preparatory procedures are required for water samples, although serum is mixed with a wetting agent (Triton X-100) to allow complete combustion of the samples and to improve analytical precision. Precautions to prevent contamination during sample handling are discussed and instrumental parameters are defined. The method has a sensitivity of 35.5 pg and detection limits of 2.3 micrograms Al/l for serum and 1.3 micrograms Al/l for water. The method was used to determine the aluminium concentration in serum of 46 normal subjects. The mean aluminium content was 7.3 micrograms/l (range 2--15 micrograms/l.

Adolescent↗

PubMed1988

An extrusion technique for handling autocuring acrylic resins.

The extrusion technique is a convenient way to place uncured resin material uniformly on flat and curved surfaces and establish precise borders. It prevents waste of material and avoids the contact of unpolymerized resin with the hands.

Acrylic Resins↗

PubMed2005

[A new look at adult chronic heart failure in Africa in the age of the Doppler echocardiography: experience of the medicine department at Yaounde General Hospital].

OBJECTIVE: Heart failure is a frequent and severe condition in Africa, yet few African data are available that take into account modern advances like echocardiography in diagnosis. This study aimed to characterize the epidemiological, clinical, etiologic and therapeutic features of heart failure at Yaounde General Hospital. METHODS: A descriptive study was carried from October 1998 to November 2001. One hundred and sixty-seven patients presenting with clinical and echocardiographic signs of heart failure were included, among which 99 men and 68 women, mean aged 57 years. RESULTS: Heart failure was the reason for 5,77% of all hospital admissions. Rehospitalisation rate was 8,33%, the prevalence 30% and overall mortality was 9,03%. 44% of patients were in class III of the NYHA and 7% in class IV. Dyspnoea was a constant symptom (95,20%); hepatomegaly was the most frequent physical finding (41,92%). Cardiac cavities were dilated and left ventricular ejection fraction was low in patients with systolic (70%) and combined (20%) dysfunction. Isolated diastolic heart failure accounted for 10% of cases. Main aetiologies were: Hypertension (54,49%), cardiomyopathies (26,34%) and valvular heart diseases (24,55%). Ischaemic heart disease was the fifth aetiology (2,39%). Medical treatment consisted of loop diuretics (90%), angiotensin-converting enzyme inhibitor (64,7%), digoxin (30,5%) and beta blockers (19,8%). CONCLUSIONS: The clinical syndrome of heart failure constitutes a major public health problem in Cameroon. Echocardiography is of paramount importance in confirming the diagnosis and precising its aetiology. Preventive and public health strategies need to be defined according to the local characteristics.

Cameroon↗

PubMed2003

Tetralogy of Fallot with subarterial ventricular septal defect.

BACKGROUND: Tetralogy of Fallot with subarterial ventricular septal defect is frequently seen among Asians. Compared with infracristal ventricular septal defect, postoperative right ventricular outflow obstruction is more likely because of subpulmonary extension of the defect. Moreover the incidence of aortic regurgitation is a concern because of the absence of a supporting infundibulum. METHODS: Four hundred cases of classic tetralogy were reviewed, 61 of which had subarterial ventricular septal defect. RESULTS: Aortic regurgitation (of more than mild degree) was identified in 7 cases with subarterial and 7 with infracristal ventricular septal defects. The mechanism of infracristal defect was predominantly an annular dilation before surgery. In contrast 5 cases with subarterial defect had progression of aortic regurgitation after operation yielding an actuarial incidence of 29.7% at 20 years. In 2 patients the cause seemed to be fixation or plication of the aortic valve annulus by the ventricular septal patch. Compared with infracristal defect, subarterial defect was associated with increased incidence of reoperation (12.0% versus 1.9% at 10 years, p = 0.01), frequent use of transannular patch (70.5% versus 45.7%, p = 0.0004), and worse New York Heart Association (NYHA) functional class (p = 0.007). Right ventricular outflow obstruction was the reason for reoperation in 3 patients with subarterial defect and was associated with worse NYHA classification in the long-term, on multivariate analysis (p = 0.0002). CONCLUSIONS: Tetralogy with subarterial ventricular septal defect was associated with worse functional outcome. To prevent adverse outcomes, precise suturing of the distal ventricular septal patch, extensive infundibulectomy, lower threshold for transannular incision, and smaller-sized ventricular septal patch placement are warranted.

Aortic Valve↗

PubMed2006

Urinary metabolic evaluations in normal and stone forming children.

PURPOSE: Urinary stone disease is relatively rare in children and urinary metabolic evaluations have been the standard in our practice. We have previously reported a high rate of urinary metabolic abnormalities in stone forming children. We compared urinary chemistry values in normal and stone forming children. MATERIAL AND METHODS: A prospective study was performed to assess urinary metabolic profiles in children with no history or a family history of urinary calculi. The 24-hour urine collections were performed and evaluated at an outside central laboratory. Urine chemistry studies were adjusted for creatinine. The data were compared to those on a historical cohort of calcium stone forming children. RESULTS: A total of 58 samples from normal children and 142 from stone forming children were evaluated. Mean age was 10 years in normal children and 12 years in stone forming children. of the normal and stone forming children 45% and 51%, respectively, were female. Supersaturation levels of calcium oxalate as well as calcium to creatinine levels were significantly higher in children with stones. No data confounding by age or sex was identified by stratification. CONCLUSIONS: There are significant differences in urinary metabolic evaluations between normal and stone forming children. This may allow more precise treatment to prevent recurrent stone episodes. We continue to perform metabolic evaluations in all children with documented urolithiasis.

Adolescent↗

PubMed2003

Comparison of T-cell-based assay with tuberculin skin test for diagnosis of Mycobacterium tuberculosis infection in a school tuberculosis outbreak.

BACKGROUND: The diagnosis of latent tuberculosis infection relies on the tuberculin skin test (TST), which has many drawbacks. However, to find out whether new tests are better than TST is difficult because of the lack of a gold standard test for latent infection. We developed and assessed a sensitive enzyme-linked immunospot (ELISPOT) assay to detect T cells specific for Mycobacterium tuberculosis antigens that are absent from Mycobacterium bovis BCG and most environmental mycobacteria. We postulated that if the ELISPOT is a more accurate test of latent infection than TST, it should correlate better with degree of exposure to M tuberculosis. METHODS: A large tuberculosis outbreak in a UK school resulted from one infectious index case. We tested 535 students for M tuberculosis infection with TST and ELISPOT. We compared the correlation of these tests with degree of exposure to the index case and BCG vaccination. FINDINGS: Although agreement between the tests was high (89% concordance, kappa=0.72, p<0.0001), ELISPOT correlated significantly more closely with M tuberculosis exposure than did TST on the basis of measures of proximity (p=0.03) and duration of exposure (p=0.007) to the index case. TST was significantly more likely to be positive in BCG-vaccinated than in non-vaccinated students (p=0.002), whereas ELISPOT results were not associated with BCG vaccination (p=0.44). INTERPRETATION: ELISPOT offers a more accurate approach than TST for identification of individuals who have latent tuberculosis infection and could improve tuberculosis control by more precise targeting of preventive treatment.

Adolescent↗

PubMed1996

How is individual risk for prostate cancer assessed?

A man's risk of developing prostate cancer is influenced by both genetic and nongenetic factors. Genetic factors are particularly important at younger ages, and the attributable risk of strong genetic factors could be as high as 43% among men less than 55 years of age; however, only about 9% of all cases may be directly attributable to a family history of prostate cancer. Race appears to be an important determinant of risk; African-American men are at high risk, whereas men of oriental ancestry are at lower risk. The bases of these racial differences remain obscure but may be related to hormonal differences. Modifiable risk factors are most important from a public health perspective. Diet or closely related factors appear to hold the most promise for prevention, although the precise factors are unknown. The strongest evidence indicates that some component of animal fat intake appears to act as a promoter of prostate cancer. Other dietary factors, including vitamin D, vitamin E, and beta-carotene and lycopene, may confer protection, but these require more study. Many but not all studies that have examined long-term effects of vasectomy suggest that this procedure may increase risk of prostate cancer, but whether this association is causal is not established. Occupational factors, smoking, and physical activity level do not appear to be major determinants of prostate cancer risk.

Dietary Fats↗

PubMed2002

Intraoperative radiotherapy given as a boost after breast-conserving surgery in breast cancer patients.

Conventional radiotherapy after breast-conserving therapy is confined to 50-55 Gy external beam radiation therapy (EBRT) to the whole breast and 10-16 Gy external boost radiation to the tumour bed or brachytherapy to the tumour bed. Local recurrence rate after breast-conserving surgery varies between 5 and 18%. External boost radiation can partially miss the tumour bed and therefore can result in local failure. Intra-operative radiotherapy (IORT) as a high precision boost can prevent a 'geographical miss'. From October 1998 to December 2000, 156 patients with stage I and stage II breast cancer were operated upon in a dedicated IORT facility. After local excision of the tumour, the tumour bed was temporarily approximated by sutures to bring the tissue in the radiation planning target volume. A single dose of 9 Gy was applied to the 90% reference isodose with energies ranging from 4 to 15 MeV, using round applicator tubes 4-8 cm in diameter. After wound healing, the patients received additional 51-56 Gy EBRT to the whole breast. No acute complications associated with IORT were observed. In 5 patients, a secondary mastectomy had to be performed because of tumour multicentricity in the final pathological report or excessive intraductal component. 2 patients developed rib necroses. In 7 patients, wound healing problems occurred. After a mean follow-up of 18 months, no local recurrences were observed. Cosmesis of the breast was very good and comparable to patients without IORT. Preliminary data suggest that IORT given as a boost after breast-conserving surgery could be a reliable alternative to conventional postoperative fractionated boost radiation by accurate dose delivery and avoiding geographical misses, by enabling smaller treatment volumes and complete skin-sparing and by reducing postoperative radiation time by 7-14 days.

Adult↗

PubMed1994

[Immunologic risks of blood transfusion and public health].

The general objective is the study, through scientific approaches, of the main components of immunological risks linked to red blood cell transfusions, as well as their consequences, in order to define precise rules for prevention, taking into account that 2,700,000 units were transfused in 1992. To reach this general aim, five intermediary objectives have to be achieved: 1) The sentinel study of the methodology used to collect information about transfusion accidents, as well as their identification and their early clinical expression; 2) The analysis of the occurrence mechanisms of incompatibilities and transfusion accidents; 3) The up-date definition of post-transfusion alloimmunization, in particular regarding 3 parameters: a) the immunogenicity of the different erythrocyte antigens, that will have to be reassessed; b) the modes of occurrence of post-transfusion anti-erythrocyte alloimmunization; c) the different types of chronology in the appearance and the persistence of anti-erythrocyte antibodies. 4) The search for significant criteria in order to assess the immunopathological correlations of the consequences of antigen-antibody conflicts; 5) The elaboration of the principles for tests evaluation and identification of the techniques linked to blood groups and the study of anti-erythrocyte antibodies.

Blood Group Incompatibility↗

PubMedDate not supplied

Visual signals used in time-interval discrimination.

Thresholds for the detection of differences in the duration of visual stimuli were determined for a variety of programs of stimulus onset and offset. Performance suffers when a time interval begins with an ON step and ends with another ON stimulus, compared to the standard ON-OFF stimulation, but the decrement is reversed when the light is ramped down to background during the interval. Neither the magnocellular nor the parvocellular streams can be excluded because there is relatively little impairment of duration discrimination when the stimulus has low contrast or is heterochromatic at isoluminance. Performance at a variety of intensity levels suggests that sustained neural firing in an early stage of visual processing provides a background activity, which prevents good temporal precision of signals.

Contrast Sensitivity↗

PubMed2000

Uniform-sized molecularly imprinted polymers for 2-arylpropionic acid derivatives selectively modified with hydrophilic external layer and their applications to direct serum injection analysis.

Uniform-sized molecularly imprinted polymers (MIPs) for (S)-naproxen and -ibuprofen selectively modified with hydrophilic external layer, restricted access media (RAM)-MIPs, have been prepared. First, the MIP for (S)-naproxen or -ibuprofen was prepared using 4-vinylpyridine and ethylene glycol dimethacrylate as a functional monomer and cross-linker, respectively, by a multistep swelling and thermal polymerization method. Next, a 1:1 mixture of glycerol monomethacrylate and glycerol dimethacrylate was used for hydrophilic surface modification, and it was added directly to the MIP for (S)-naproxen or -ibuprofen 4 h after the start of molecular imprinting. The obtained RAM-MIP material for (S)-naproxen or -ibuprofen was applied for direct serum injection assays of the drug by a column-switching system, consisting of a RAM-MIP material and conventional C18-silica column. However, leakage of the imprint molecule prevented accurate and precise assays of the drug. This problem has been overcome by using the RAM-MIP for (S)-naproxen for the assays of ibuprofen in rat plasma. The optimized column-switching system was applied successfully to the assay of ibuprofen in rat plasma after oral administration.

Animals↗

PubMed2006

Biomechanical stability of a retrotubercle opening-wedge high tibial osteotomy.

In recent years, opening-wedge osteotomy has gained popularity. However, the complication rate reported is high. Opening-wedge osteotomy was modified to remedy the problems seen with the conventional technique including loss of correction, delayed healing, and patella infera. This biomechanical study evaluates the response of a new opening-wedge osteotomy in a static and dynamic mode of human cadavers. Results were compared to the stability of the conventional technique. Six preserved pairs of human cadaveric knees were tested. Specimens of the same pair were randomly assigned to either the modified or conventional osteotomy. Internal fixation was used to ensure precise correction and prevent bone collapse. Each tibia was loaded on a material testing system from 0 to 700 N for 10,000 cycles to simulate immediate full weight bearing in a walking individual. Specimens were then loaded to failure to determine ultimate load and stiffness of the construct. Displacement of the articular fragment and stiffness were measured during dynamic loading. Load to failure, displacement, and stiffness were measured during static testing. The modified osteotomy provided significantly greater stiffness (1392 N/mm) and smaller loss of correction (.68 mm) than the conventional osteotomy (741 N/mm; 1.76 mm) under cyclic loading conditions (P<.05). The modified retrotubercle osteotomy provides greater stiffness than the conventional osteotomy, increasing stability by 62% and minimizing loss of correction to <1 mm. The modified osteotomy eliminates the need for bone graft and provides additional strength to allow accelerated rehabilitation.

Aged↗

PubMed1981

[Indications and clinical aspects of granulocyte transfusions (author's transl)].

Granulocyte transfusions (n = 222) were administered to 41 patients with granulocytopenia (less than 500 X 10(6)/1) and antibiotics-resistant infections. The average granulocyte content per transfusion was 2.1 X 10(10), 212 transfusions had been obtained by filter leucapheresis. Infections improved in 25 episodes, and 18 patients survived the 30th day. There was no influence in 18 episodes and only 2 patients survived beyond the 30th day. Extent and duration of bone marrow insufficiency, and type and grade of infection, clearly influenced prognosis. Further prognostically relevant risk factors were age (greater than 60 years) and platelet deficiency (less than 20 X 10(9)/1), as well as liver and renal insufficiency. Adherence to precise guidelines may prevent pointless transfusions.

Adolescent↗

PubMed1998

Regulation of Ich-1 pre-mRNA alternative splicing and apoptosis by mammalian splicing factors.

The importance of alternative splicing in regulating apoptosis has been suggested by findings of functionally antagonistic proteins generated by alternative splicing of several genes involved in apoptosis. Among these, Ich-1 (also named as caspase-2) encodes a member of the caspase family of proteases. Two forms of Ich-1 are produced as a result of alternative splicing: Ich-1L, which causes apoptosis, and Ich-1S, which prevents apoptosis. The precise nature of Ich-1 alternative splicing and its regulation remain unknown. Here, we show that the production of Ich-1L and Ich-1S transcripts results from alternative exclusion or inclusion of a 61-bp exon. Several splicing factors can regulate Ich-1 splicing. Serine-arginine-rich proteins SC35 and ASF/SF2 promote exon skipping, decreasing the ratio of Ich-1S to Ich-1L transcripts; whereas heterogeneous nuclear ribonucleoprotein A1 facilitates exon inclusion, increasing this ratio. Furthermore, in cultured cells, SC35 overexpression increases apoptosis; whereas heterogeneous nuclear ribonucleoprotein A1 overexpression decreases apoptosis. These results provide the first direct evidence that splicing factors can regulate Ich-1 alternative splicing and suggest that alternative splicing may be an important regulatory mechanism for apoptosis.

Alternative Splicing↗