Biomedical subjects

F Frank

Publications and source records attributed to F Frank.

At least 19 recordsLinked to original sources

PubMed2006

A rapid method for assessing the environmental performance of commercial farms in the Pampas of Argentina.

The generation of reliable updated information is critical to support the harmonization of socio-economic and environmental issues in a context of sustainable development. The agro-environmental assessment and management of agricultural systems often relies on indicators that are necessary to make sound decisions. This work aims to provide an approach to (a) assess the environmental performance of commercial farms in the Pampas of Argentina, and (b) propose a methodological framework to calculate environmental indicators that can rapidly be applied to practical farming. 120 commercial farms scattered across the Pampas were analyzed in this study during 2002 and 2003. Eleven basic indicators were identified and calculation methods described. Such indicators were fossil energy (FE) use, FE use efficiency, nitrogen (N) balance, phosphorus (P) balance, N contamination risk, P contamination risk, pesticide contamination risk, soil erosion risk, habitat intervention, changes in soil carbon stock, and balance of greenhouse gases. A model named Agro-Eco-Index was developed on a Microsoft-Excel support to incorporate on-farm collected data and facilitate the calculation of indicators by users. Different procedures were applied to validate the model and present the results to the users. Regression models (based on linear and non-linear models) were used to validate the comparative performance of the study farms across the Pampas. An environmental dashboard was provided to represent in a graphical way the behavior of farms. The method provides a tool to discriminate environmentally friendly farms from those that do not pay enough attention to environmental issues. Our procedure might be useful for implementing an ecological certification system to reward a good environmental behavior in society (e.g., through tax benefits) and generate a commercial advantage (e.g., through the allocation of green labels) for committed farmers.

Agriculture↗

PubMed2001

Calpha methylation in molecular recognition. Application to substance P and the two neurokinin-1 receptor binding sites.

Two binding sites NK-1M (major, more abundant) and NK-1m (minor) are associated with the neurokinin-1 receptor. For the first time with a bioactive peptide, the Calpha methylation constraint, shown to be a helix stabiliser in model peptides, was systematically used to probe the molecular requirements of NK-1M and NK-1m binding sites and the previously postulated bioactive helical conformation of substance P (SP). Seven Calpha methylated analogues of the undecapeptide SP (from position 5-11) have been assayed for their affinities and their potencies to stimulate second messenger production. The consequences of Calpha methylation on the structure of SP have been analysed by circular dichroism and nuclear magnetic resonance combined with restrained molecular dynamics. The decreased potencies of six out of these seven Calpha methylated SP analogues do not allow the identification of any clear-cut differences in the structural requirements between the two binding sites. Strikingly, the most active analogue, [alphaMeMet5]SP, leads to variable subnanomolar affinity and potency when interacting with the NK-1m binding site. The conformational analyses show that the structural consequences associated with Calpha methylation of SP are sequence dependent. Moreover, a single Calpha methylation is not sufficient by itself to drastically stabilize a helical structure even pre-existing in solution, except when Gly9 is substituted by an alpha-aminoisobutyric acid. Furthermore, Calpha methylation of residues 5 and 6 of SP in the middle of the postulated helix does not stabilize, but decreases (to different extents) the stability of the helical structure previously observed in the 4-8 domain of other potent SP analogues.

Animals↗

PubMed2000

The effect of placental subfractions on Trypanosoma cruzi.

Five subfractions were collected from six term placentas by mincing and differential centrifugation: homogenate, nuclear, mitochondrial, lysosomal, and supernatant. The effect of each subfraction on Trypanosoma cruzi was assessed by trypan blue exclusion, relative infectivity of mice, and penetration of susceptible cultured VERO cells. Ultrastructural changes in trypomastigotes were identified after high cell mortality was shown by dye exclusion following treatment with lysosomal and supernatant fractions. Trypomastigotes treated with other subfractions or preheated subfractions, those recovered from infected VERO cells, and controls remained unaffected. This was confirmed by the ability of treated trypomastigotes to infect mice or to penetrate susceptible cultured VERO cells. There were a 48% decrease in parasitemia and fewer myocardial lesions in Balb/c mice following treatment with the lysosomal subfraction compared to homogenate and controls. VERO cells were invaded about half as often after lysosomal treatment compared to controls (P < 0. 05); an 11% decrease in cell invasion following homogenate treatment was not significant. Placental lysosomal enzyme activity was unaffected by trypomastigotes. Human placentas contain one or more heat-labile substances in lysosomal and supernatant subfractions which inhibit or injure trypomastigotes of T. cruzi in cell-free systems.

Animals↗

PubMed2000

Helicobacter pylori infection in recurrent abdominal pain.

BACKGROUND: Helicobacter pylori is associated with chronic gastritis and peptic ulcer in adults and in children. The purpose of the present study was to analyze the association of recurrent abdominal pain and H. pylori infection in children and to evaluate the efficacy of antimicrobial treatment in patients with evidence of infection. METHODS: The clinical and histopathologic findings in children who underwent diagnostic upper endoscopy for recurrent abdominal pain were analyzed retrospectively. Patients with evidence of infection with H. pylori were treated with a combination of omeprazole, amoxicillin, and clarithromycin. Efficacy of treatment was assessed using the 13C-urea-breath test. RESULTS: H. pylori was found in histopathologic sections of 29 (40%) of 73 patients undergoing diagnostic endoscopy for recurrent abdominal pain. Five children (17%) were of Swiss ethnic origin, and 24 (83%) were non-Swiss. All the infected patients had chronic gastritis and 4 (14%) had ulcerations in the duodenum. Treatment with omeprazole, amoxicillin, and clarithromycin resulted in eradication of the infection in all and in resolution of the clinical symptoms in 15 (80%) of 19 patients who had a follow-up examination. CONCLUSIONS: The presented data suggest that gastritis induced by H. pylori may be associated with recurrent abdominal pain and that in Switzerland infections with H. pylori primarily involve persons who are non-Swiss. A combined therapy results in eradication of the bacterium and in improvement of the clinical symptoms in a significant majority of the patients.

Abdominal Pain↗

PubMed1997

Primary non-Hodgkin's lymphoma of the sciatic nerve followed by localization in the central nervous system: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: A unique case of primary non-Hodgkin's lymphoma of the sciatic nerve followed by multiple loci in the central nervous system is described. CLINICAL PRESENTATION: The lesion occurred in a 44-year-old immunocompetent man with a palpable mass in the left popliteal fossa and a 10-month history of progressive weakness and numbness of the left foot. The tumor was a diffuse large lymphoma of B-cell origin of an intermediate grade of malignancy according to the criteria of the International Working Formulation. INTERVENTION: Because diagnosis of the malignant lymphoma was performed on frozen section, resection of the nerve trunk was avoided. The patient was treated with radiotherapy and chemotherapy. At 6 months after the discovery, biopsy, and treatment of the sciatic nerve lymphoma, other lesions demonstrating the same histological features were observed in the central nervous system. The patient died 4 years and 2 months after presentation as a result of the central nervous system lesions and without clinical evidence of systemic extraneural localization. CONCLUSION: A review of the literature indicates that primary peripheral nerve lymphomas occur in the sciatic nerve. These cases, and the case described in our study, share common clinicopathological findings that justify discussing them separately as distinct entities.

Adult↗

PubMed1996

Distribution and transmission of Pseudomonas aeruginosa and Burkholderia cepacia in a hospital ward.

Genotyping and antibiotic susceptibility testing were used to analyze Pseudomonas aeruginosa and Burkholderia cepacia strains from sink drain from 14 pediatric patients with cystic fibrosis (CF) and from hospital personnel as part of a 4 week prospective study of strain transmission in a pediatric ward. A total of 87.5% of all washbasin drains were contaminated with P. aeruginosa [10(2) to 10(5) colony forming units (CFU)/ml sink fluid], whereas B. cepacia was found only once in a sink drain. From the eight CF patients already infected with P. aeruginosa upon entering the ward, we isolated six genotypes that were identical with strains found in sink drains of the ward. Four of the 16 members of the personnel had one positive P. aeruginosa hand culture. B. cepacia was never found in patients or on personnel hands. Hand washing in contaminated sinks (> or = 10(3) CFU/ml) led to positive P. aeruginosa or B. cepacia hand cultures. P. aeruginosa or B. cepacia embedded in sputum were transmissable by hand shaking for up to 180 min, whereas both pathogens suspended in physiological saline were transmissable to other hands only up to 30 min. Genotyping of P. aeruginosa revealed strain transmission from CF patients or the environment to other patients or the personnel, as well as one transmission from the environment to a CF patient. The ability of CF sputum to prolong survival of P. aeruginosa and B. cepacia may be important for strain transmission. The results suggest that improved hygienic measures are required to prevent routes of bacterial transmission via the hands and sink drains.

Adolescent↗

PubMed1995

Cleavage of lymphocyte surface antigens CD2, CD4, and CD8 by polymorphonuclear leukocyte elastase and cathepsin G in patients with cystic fibrosis.

Polymorphonuclear leukocytes (PMN) accumulating in airways of patients with cystic fibrosis (CF) as a response to chronic endobronchial bacterial lung infection, release lysosomal serine proteinases such as PMN-elastase at concentrations of approximately 0.5 microM to 5 microM into the airway lumen. Immunohistology of CF lung material and fluorescence activated cell sorter analysis of sequential CF bronchoalveolar lavages demonstrated loss of the CD4 and CD8 Ag on CD3+ T lymphocytes in sputum-filled airways. In 10 CF sputum samples 1.0%, 19.1%, and 15.7% of all CD3+ T lymphocytes expressed CD4, CD8, and CD2, respectively. Incubation of CF sputum supernatant fluids with peripheral blood T lymphocytes resulted in total reduction of CD4 and CD8 but not CD2. Addition of alpha 1-proteinase inhibitor abolished surface Ag cleavage completely. Purified PMN-elastase and cathepsin G cleaved CD2, CD4, and CD8 on peripheral blood T lymphocytes at proteinase concentrations of 0.83 to 8.3 microM in a dose-dependent manner. Cleaved CD4 and CD8 were reexpressed on the surface of T lymphocytes after 24 h in the absence of PMN-elastase. Incubation of a CD4+ T cell clone with PMN-elastase lead to a significant reduction of cytotoxicity toward target cells and significantly reduced IL-2 and IL-4 production. The results suggest a temporary functional impairment of T lymphocytes in foci of high inflammation characterized by stimulated PMN, which may lower tissue destruction.

Adult↗

PubMed1995

Internal exposure of waste incineration workers to organic and inorganic substances.

One hundred and twenty-two persons employed in an industrial waste incineration plant were examined with respect to organic and inorganic substances which may be produced during the combustion of different waste. The employees were divided into three groups: persons with contact with the incinerator (WI workers, n = 45), periphery workers (n = 54) and management (n = 23). For the evaluation of internal exposure, the levels of lead, cadmium, mercury, benzene, toluene, ethylbenzene and m-xylene in blood, chromium in the erythrocytes, polychlorinated biphenyls, hexachlorobenzene and pentachlorophenol in plasma, and arsenic, chromium, nickel, vanadium, chlorophenols and hydroxypyrene in urine were determined. The internal exposures of the three groups were tested against each other and were compared with the reference values of the general population. Differences between the groups investigated were tested using the U test according to Wilcoxon, Mann and Whitney (P < 0.05). The biological exposure limits valid in Germany (BAT values) were not exceeded in any cases. Compared with the background levels of the German population, certain parameters were exceeded in several employees. Significantly higher levels of the WI workers in comparison to both periphery workers and management were found for toluene in blood (median: 1.1 vs 0.9 vs 0.6 microgram/l). For the lead and cadmium levels in blood and for the urinary excretion of arsenic, 2,4-dichlorophenol and tetrachlorophenols, statistical differences were found only between WI workers and one of the other groups. However, in all cases the elevations were very small and of interest more from the environmental than from the occupational point of view. It must be stressed that this waste incineration plant is very modern in terms of worker health and safety. At older plants without corresponding health and safety measures, higher internal exposure of the employees to hazardous substances may exist.

Adult↗

PubMed1995

Stereotactic management of craniopharyngiomas.

The authors present a series of 47 patients with craniopharyngiomas treated by stereotaxy in the past 15 years. There was no mortality nor immediate postoperative morbidity in the treatment of the cystic portion of the neoplasm. Intracavitary colloidal yttrium (90Y) was extremely effective in obtaining long-lasting disappearance of craniopharyngioma cysts. In children, yttrium worsened panhypopituitarism, while it was well tolerated by teenagers and adults. Craniopharyngiomas are often mixed (solid-cystic) and the majority of cases have a predominant cystic portion, where stereotaxy is a valid alternative to open surgery, which presents a high morbidity and mortality.

Adolescent↗

PubMed1994

Surgical management of cavernous angiomas in children.

Cavernous angiomas are vascular malformations affecting any part of the central nervous system (CNS). The management of asymptomatic cavernous angiomas is still debated due to their poorly understood natural history, although more data are now available regarding results of surgical treatment in symptomatic cases. The authors report their surgical experience with 18 pediatric patients operated on for symptomatic CNS cavernous angiomas. The children ranged in age from 10 months to 17 years, without a relevant sex difference. Cavernous angiomas were intracranial in 17 cases: 15 being in the supratentorial compartments and two in the cerebellum. Clinical manifestations were as follows: seizures in 11 cases, focal neurologic deficits in five, and headache in one. The 18th case was observed in a girl showing paraparesis in the spinal subdural-extramedullary space at T8-T9 level. Excision of four deep cerebral lesions was performed after stereotactic localization through non-eloquent cortex. Pathologic confirmation of cavernous angiomas was obtained in all patients. Mortality from surgical procedures was absent in this series. The follow-up period ranged from 1 to 16 years. All 11 epileptic patients obtained seizure control; improvement or stabilization of neurologic symptoms was observed in the remaining seven patients.

Adolescent↗

PubMed1993

[Interstitial laser coagulation of benign prostatic hyperplasia].

We report on the new method of interstitial laser coagulation for the treatment of benign prostatic hyperplasia (BPH). The procedure is based on the interstitial application of Nd:YAG laser irradiation, delivered through a new light guide system. Such light applicators coagulate constant tissue volumes in a homogeneous manner, as proven by in vitro studies in different tissues, including surgically removed prostate adenoma. The extent of the coagulation is determined by laser power and irradiation time. At 5 W, for example, and during a 10-min period, this zone reached a diameter of up to 20 mm. Temperatures generated in the process were over 100 degrees C, as measured by time/space resolution. These results were confirmed by in vivo studies in canine prostates. In the course of 7 weeks, the coagulated areas formed scars with degeneration and fibrosis, accompanied by marked shrinking. Neighbouring organs were not affected. The method was successfully transferred to clinical practice. The application of the light guides to the lateral lobes was performed percutaneously from the perineum under transrectal ultrasound guidance. The median lobe was punctured transurethrally under direct vision. Twenty-seven patients with an average age of 67.7 years were treated between July 1991 and March 1992. At the time of evaluation 15 patients had a follow-up of more than 2 months. They experienced a mean increase of peak flow rate from 6.6 to 15.2 ml/s and a mean decrease of residual volume from 206 to 38 ml. This was accompanied by a marked lessening of symptoms. The average prostate weight decreased from 63 to 44 g. Sexually active patients did not experience retrograde ejaculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Surgical voice rehabilitation after laryngopharyngectomy. Functional results of tracheo-hypopharyngeal shunts by jejunal transplantation.

For surgical voice rehabilitation after pharyngolaryngectomy we use the technique of placing a siphonlike jejunal interposition in order to create a tracheohypopharyngeal shunt. In this paper we present the functional benefits of this method of voice rehabilitation. The best results achieved are compared with a normal voice using the following test parameters: electroacoustic sound analyses and voice status. The findings show that the siphon voice is adequate for everyday purposes and can achieve useful social verbal communication.

Anastomosis, Surgical↗

PubMed1992

Primary intrasellar germinoma: case report.

Intracranial germinomas arising primarily within the sella turcica are extremely rare. Preoperative diagnosis is difficult to establish even with sophisticated procedures. Diabetes insipidus is the main clinical manifestation. The authors report a case of an apparently primary intrasellar germinoma causing subclinical pituitary apoplexy in a 12-year-old boy. The transsphenoidal approach and appropriate radiotherapeutic management were employed with a good outcome.

Child↗

PubMed1990

Application systems for intracorporeal laser-induced shockwave lithotripsy using the Nd:YAG Q-switched laser.

For laser-induced shockwave lithotripsy, the electromagnetic energy of a laser light pulse is converted intracorporeally into the acoustic energy of a shockwave. The lithotriptor is based on a specially developed, Q-switched Nd:YAG laser whose high power light pulses (70 mJ, 25 nsec) are coupled into a flexible quartz fiber with a core diameter of 600 mum. Using focusing elements, energy densities higher than 6 x 10 5 J m -2 can be achieved, resulting in an optical breakdown in water followed by a shockwave. As a result of different absorption mechanisms, the breakdown threshold can be decreased by placing a metallic target into the laser beam. The different shockwave formations of such optomechanical transducers have been measured. First clinical applications have been performed.

Equipment Design↗

PubMed1989

[Intracorporeal shockwave lithotripsy using the neodymium YAG laser].

The problem of suitable energy transfer and conversion for intraureteral lithotripsy has not yet been solved satisfactorily. Laser-induced shockwave lithotripsy (LISL) appears to be a very promising solution to this problem. We report on initial clinical experience using a Q-switched Nd:YAG laser generating a shockwave on the metallic surface of an optomechanic coupler. This leads to the fine fragmentation of a urinary calculus situated close to or in contact with the coupler. Only minimal side effects occur in biological tissue. Further development of the coupler resulted in considerable increase of its fragmentation capability with no increase in side-effects. As a result, application under fluoroscopic control alone became possible, which appears adequate in approximately half of the cases. In the other half visual inspection via ureteroscopy is required. Laser-induced lithotripsy is the only technique that uses a flexible transmission system, results in the fine fragmentation of calculi, and is free of serious side effects on tissue, i.e. does not lead to perforation of the wall of the ureter.

Humans↗

PubMed1989

Stereotactic mesencephalic tractotomy in the treatment of chronic cancer pain.

A report is given on indications and results of treatment of chronic cancer pain using stereotactic mesencephalic tractotomy (SMT), based on own experiences in 202 patients. Percutaneous cervical cordotomy for upper body pain syndromes has been abandoned and replaced by SMT. Operative mortality of SMT was less than 0.5%, and also its morbidity was low and usually transitory. Bilateral procedures may be performed with an interval of at least seven days. Early recurrences within one month (15%) are due to insufficient coagulation. Late pain recurrence occurred in 4% and may be due to either nervous system regeneration (sprouting) or transmission of pain by alternate secondary pathways.

Chronic Disease↗

PubMed1989

Percutaneous surgical treatment of trigeminal neuralgia.

The authors report on indications and results of percutaneous surgical treatment of trigeminal neuralgia based on own experiences in 1124 cases. In 912 cases percutaneous thermorhizotomy and in 212 cases percutaneous microcompression have been used. As a conclusion the following considerations have been stressed: I) In both methods slight hypaesthesia appears to obtain good pain relief; II) Percutaneous thermorhizotomy is indicated in third division neuralgias; III) Percutaneous microcompression is indicated for first and second division neuralgias only when the trigeminal cistern is not abnormally dilated; IV) Undesirable side-effects after either thermorhizotomy and microcompression are similar and transitory in most cases; V) Pain recurrence for both procedures are comparable and range at about 25%.

Humans↗

PubMed1989

Availability of infective larvae of parasitic nematodes of sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall area.

Thirteen groups of 4 South African mutton Merinos grazed for 4 weeks with the flock on Kikuyu pastures and were slaughtered for total and differential worm counts at necropsy. Subsequently 12 groups of 8 week tracers grazed on the pastures and were killed for worm counts post mortem. The following were present in most sheep: Teladorsagia (syn. Ostertagia) circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Dictyocaulus filaria and Oesophagostomum venulosum. Haemonchus contortus, Nematodirus spathiger and Trichuris skrjabini were less frequently recovered. Optimal conditions for infestation of grazing sheep occurred from June (late autumn)--October (spring) when mean temperatures in any 4 week period were less than 20 degrees C and a total of greater than 40 mm of rain fell on 8 or more separate days. When the mean temperatures exceeded 20 degrees C pastures were safe, sheep acquiring less than 1,000 worms in 4 weeks.

Animals↗