Image acceleration of highly charged ions by metal surfaces.
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Biomedical subjects
Publications and source records attributed to F Meyer.
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Second primary cancers often occur in head and neck cancer patients successfully treated by radiation therapy. Experimental and epidemiological data suggest that these second primaries might be prevented by antioxidant vitamins, in particular beta-carotene and alpha-tocopherol. A randomized double-blind clinical trial is being conducted in Canada to determine whether vitamin supplementation with beta-carotene (30 mg/d) and alpha-tocopherol (400 IU/d) reduces the incidence of second primaries in head and neck cancer patients treated by radiation therapy.
About 13% of patients treated for a pharyngeal cancer suffer from a second primary cancer. Excessive consumptions of tobacco and/or alcohol are recognized as risk factors of second primary cancers in these patients. Epidemiologic studies suggest that antioxidant vitamins could have a protective effect on the occurrence of second primary cancers; however, this hypothesis should be confirmed by randomized clinical trials. A better knowledge of the risk factors of second primary cancers in patients with a pharyngeal cancer could help reducing the occurrence of second primary cancers and improving the follow-up of these patients.
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When a family of genes from closely related organisms is known, there is a certain change to extract the corresponding gene from the genome of another related organism. This can be done by polymerase chain reaction, provided that a pair of suitable primers can be designed. In contrast to primer design for a single, known target sequence, systematic primer design for an unknown target given a group of homologues can by no means be done manually. GeneFisher is a software tool which automates this task, and takes special care to make the impact of the manifold design parameters transparent to the user.
Aside from knowledge of the respective causes in women and men, the therapy of couples with unfulfilled wish for a child requires the patients' willingness to submit to treatment. From a psychological point of view, the extent of the suffering is focused on, to be presupposition of the patients' compliance. Results from various research groups suggest that men tend to portray themselves as being especially unstressed. In the following report, considerations about the consequences to the doctor-patient relationships in andrology will be depicted. Among other things, the problematic relationship between the men affected and their fathers will be discussed as a possible cause of the self images of these men.
OBJECTIVE: This study assessed the relationship between vitamin supplement use and the occurrence of ischemic heart disease (IHD). DESIGN: A cohort study was conducted between 1985 and 1991 in Quebec City. In 1985, 2313 men provided baseline information on vitamin supplement use and IHD risk factors. Incidence of IHD events was ascertained over the first five years of follow-up. Cox regression models were used to assess the relation between vitamin supplement use and occurrence of IHD events while controlling for confounders. MAIN RESULTS: Vitamin supplement use was consistently associated with a lower incidence of IHD. The adjusted rate ratios and their 95% confidence intervals were: 0.31 (0.09-0.99) for IHD death, 0.53 (0.24-1.11) for MI, 0.76 (0.44-1.65) for angina and 0.73 (0.44-1.22) for a first IHD event. The associations were stronger for IHD death and myocardial infarction, two events assessed with high validity. The inverse association with IHD was more consistent for vitamin E than for any other vitamin. CONCLUSION: This study suggests that the inverse association between vitamin supplement use and IHD is real. The causal nature of the association can only be demonstrated in the context of a randomised intervention trial such as the HOPE study.
During a large measles outbreak in Quebec City in 1989, two investigations conducted in parallel evaluated the relative risk of measles and measles vaccine effectiveness with respect to age at vaccination. The study was a school-based case-control study including 563 cases and 1126 classmate controls. The second was a cohort study of the siblings of school cases including 493 siblings aged between 1 and 19 years. The relative risks (RR) of measles were similar in both settings and the trend towards increased vaccine efficacy with increasing age at vaccination was highly significant (P < 0.001). Vaccine efficacy rose from 85% in children vaccinated at 12 months of age to > or = 94% in those vaccinated at 15 months and older. Even for children vaccinated at or after 18 months of age, the RR of measles was reduced when compared with children vaccinated between 15 and 17 months of age (RR 0.61, CI 95% 0.33-1.15). Small changes in the timing of initial measles vaccination can have a major impact on vaccine efficacy.
The early pathogenetic steps that finally lead to acinar cell necrosis in acute pancreatitis have been characterized only scarcely as yet. Among a lot of hypotheses, one concept favors disturbances of cellular energy metabolism as a major factor that contributes to preterm cell decline. To investigate, whether an experimental acute pancreatitis alters cell respiration, the respiratory capacities of acinar cells isolated from rats with acute pancreatitis were measured. Acute pancreatitis was induced using Popper's model, i.e., a combination of duct obstruction, secretory stimulation, and mesenteric short-term ischemia with subsequent reperfusion. Acinar cells were isolated using a collagenase digestion technique. The respiratory rates of the isolated cells in suspension were measured at 37 degrees C in 100% oxygen-saturated N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid-buffered Eagle's-minimal essential medium. Resting respiration of the acinar cells uniformly amounted to about 60 pmol of O2/s x 10(6) cells in both the control and the pancreatitis group. Cellular respiration could significantly be stimulated by stepwise uncoupling of oxidative phosphorylation by means of 2,4-dinitrophenol in all cell suspensions investigated. The maximum rate of stimulated respiration was diminished in the cells isolated from rats with acute pancreatitis as compared with the controls (79.3 +/- 5.0 vs. 160.2 +/- 15.5 pmol of O2/s x 10(6) cells, p < .05), however. This reduced respiratory load capacity of the acinar cells in acute pancreatitis reflects the restricted ability of the cells to increase respiration on enhanced cellular demand. Since mitochondrial respiration is coupled to oxidative phosphorylation, an altered energy-transforming potential of the acinar cells in acute pancreatitis becomes evident.(ABSTRACT TRUNCATED AT 250 WORDS)
Twelve 9- to 12-year-old children performed four exercise-in-the-heat trials (35 degrees C, 45% RH), which differed in the fluids consumed. In each trial, subjects were kept euhydrated while cycling one 20-min and two 15-min bouts at 50% peak VO2 followed by a 90% peak VO2 bout until exhaustion. Thereafter, they could drink ab libitum while resting. One drink was water, and the other three drinks had 6% CHO with different Na+: 0, 8.8, and 18.5 mEq.L-1. All drinks had the same grape flavor. The perceived thirst was similar among trials and it did not increase while subjects were exercising. On average, subjects felt their stomach "somewhat full" with no difference among drinks. Thermal sensations, RPE, and overall comfort were similar among trials. During a 30-min recovery, volume intake was similar among drinks (201 +/- 27 ml). In conclusion, the drink composition did not affect perceptual responses to drinking while euhydrated children exercised in the heat, nor did it affect drinking behavior during recovery.
There is increasing awareness that growth hormone (GH) replacement therapy is also essential in adult patients with growth hormone deficiency (GHD). There are little data available on the dose requirements for replacement therapy in this age group. In childhood, the growth response to GH therapy can serve as an indicator for correct replacement dose. Because this indicator does not exist in adults, we analyzed growth factors and biochemical markers of bone metabolism by specific radioimmunoassays in a group (n = 12) of adult patients (age, 20.0-31.6 years) with GHD with childhood onset before and after a 4-week treatment period (daily, s.c.) with recombinant, human GH at different doses (0.125, 0.25 and 0.5 IU/kg body weight/week). Comparing the basal levels to those on low-dose GH (0.125 IU/kg/week) and on a high dose (0.5 IU/kg/week), the following results were obtained. Insulin-like growth factor-I (IGF-I) in serum: basal, 68.6 +/- 37 ng/ml; low dose, 176.9 +/- 65 ng/ml (p < or = 0.05); high dose, 380.6 +/- 200 ng/ml (p < or = 0.01). IGF-binding protein-3 in serum: basal, 2.13 +/- 0.58 mg/l; low dose, 3.23 +/- 0.84 mg/l (p < or = 0.01); high dose, 3.97 +/- 0.82 mg/l. Osteocalcin in serum: basal, 3.88 +/- 1.27 ng/ml; low dose, 7.01 +/- 2.20 ng/ml (p < or = 0.01); no further increase. Procollagen-I peptide in serum: basal, 113.6 +/- 36.7 microgram/l; low dose, 211.6 +/- 90.4 microgram/l (p < or = 0.01); no further increase.(ABSTRACT TRUNCATED AT 250 WORDS)
Xerophthalmia is a term covering a range of ophthalmologic manifestations due to vitamin A deficiency. This condition occurs in preschool children in tropical regions affected by protein-caloric malnutrition. Clinical manifestations of the disease have been summarized in the 1974 five-grade WHO classification. Clinical diagnosis was traditionally made using a slit lamp to detect the pathognomonic manifestations and consequences of corneal and conjunctival xerosis. Currently diagnosis is greatly facilitated by determination of plasma levels using a micromethod, especially the relative dose response (RDR) test, and by conjunctival impression cytology (CIC). CIC is a simple and reliable method which allows mass screening and thus more effective evaluation of the impact of xerophthalmia on public health in Africa. The relationship between xerophthalmia and measles is complex. Vitamin A deficiency promotes measles which can in turn hasten perforation of keratomalacia especially in undernourished children. Vitamin A has a beneficial effect on both xerophthamia and measles. Curative and prophylactic administration of vitamin A at doses recommended by the W.H.O. considerably reduces not only xerophthalmia-related morbidity but also child mortality in tropical areas.
Harada's disease is a uveo-meningitis syndrome characterized by meningo-encephalic manifestations preceded by bilateral posterior uveal lesions. The etiology of Harada's disease is still unclear but it probably involves an auto-immune reaction to melanocytes. This mechanism would account for the high incidence of Harada's disease in dark-skinned patients. This report describes a case of Harada's disease that occurred in a 28-year-old woman from North Africa. Ophthalmologic manifestations were typical with regard to clinical features and course involving bilateral papillary edema followed by exsudative detachment of the retina and diffuse cicatricial epitheliopathy of the posterior poles. However neurologic signs were mild, the main finding being atypical headache, and this particularity delayed diagnosis. Limited cerebral involvement that did not coincide with ocular lesions explains the fact that a thorough search for posterior uveal involvement with the aforesaid features was necessary. Although it occurs mainly in dark-skinned Asians, Harada's disease deserves the attention of physicians practicing in tropical areas.
The most common manifestations of Lyme disease are neurologic and rheumatologic, but ophthalmologic lesions can also occur and may even be dominant. The authors describe a case of bilateral optic neuropathy associated with Lyme borreliosis that quickly led to near-total blindness. In addition to a loss in visual acuity and field bilateral papillary edema was documented by angiofluorography. A spectacular improvement was obtained under combined antimicrobial therapy using doxycycline and corticosteroid therapy. The patient rapidly recovered full vision. These observations are discussed within the context of Lyme disease with a review of other relevant ophthalmologic complications. The importance of careful interpretation of serology is emphasized.
Twelve 9- to 12-year-old children (6 boys, 6 girls) performed four exercise-in-heat (35 degrees C, 45% RH) trials which differed in the composition of the fluids they drank. In each trial, subjects cycled for one 20-min and two 15-min bouts at 50% peak VO2 with 10-min rest periods in between. In a fourth bout, they cycled at 90% peak VO2 until exhaustion. Drinks had the same grape flavor and were assigned in a double-blind design and in a Latin-square order. Subjects drank 7 ml.kg-1.h-1 to keep them euhydrated. Three of the drinks had 6% carbohydrates (CHO), with different [Na+]: 0, 8.8, 18.5 mmol.l-1 and one drink had neither CHO nor Na+ (WATER). Among drink trials, there were no differences in the increase in rectal temperature, HR, or performance time to exhaustion. Despite the larger Na+ deficit induced by the Na(+)-free drinks compared with the Na+ drinks (11.8 +/- 1.4 vs 5.7 +/- 0.9 mmol.h-1), neither plasma [Na+] nor osmolality were affected. These results suggest that electrolyte, as in the above conditions, did not affect electrolyte balance, thermoregulatory responses, or aerobic performance of children exercising in the heat. The greater Na+ deficit induced by ion-free drinks was of minor biological importance.
Differential diagnosis of uncertain swelling of the neck has a limited number of possibilities. Thyreoideal processes, lymphatic adenomatosis and abscesses are in most of these cases prevent. However, vascular diseases should be also considered. It is current practice to perform a sonography, completed by computertomography for establishing a diagnosis. If vascular disease is suspected also an angiography is indicated. During the diagnostic procedure we discovered a major aneurysm of the left external carotid artery. The aneurysm was resected and vascular continuity restored by PTFE patchplasty. In case of tumorous processes of the neck extracranial aneurysms of the carotid artery have to be included into the differential diagnosis in order to guarantee adequate therapy.
Less than 1% of all complications following vascular surgery of the abdominal aorta involve the lymphatic system. We report on a case of Chylous ascites following the operation of a ruptured infrarenal aortic aneurysm. The primary therapy, administered over a period of five weeks, consistent of diuretics and substitution by human albumin. However, the chylous flow did not decrease. A surgical intervention by a retroperitoneal ligation to try to stop the lymph flow also failed. Finally a total parental nutrition was followed by decrease and arrest of the lymph flow. Conservative treatment of this complication is considered as therapy of choice.
The pheromone 3-encoding gene (phr3) of Euplotes octocarinatus was expressed in Escherichia coli using a novel expression-secretion vector. The vector, pExSec1, contains a strong and tightly regulated T7 promoter, the corresponding Shine-Dalgarno sequence and the T7 terminator region. Translation starts at the protein A leader sequence followed by the synthetic ZZ sequence of protein A. The expression-secretion modules are embedded in the high-copy-number plasmid vector, pUK21, which carries a kanamycin-resistance marker (KmR). The produced ZZ-pheromone 3 (Phr3) fusion protein was secreted into the culture medium of the host cells. It was isolated by affinity chromatography and was further purified by gel filtration. After refolding with protein disulfide isomerase (PDI), the fusion protein exhibited the same high activity as the native pheromone.