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Biomedical subjects

R Schenker

Publications and source records attributed to R Schenker.

18 recordsLinked to original sources
PubMed2006

Efficacy of a milbemycin oxime-praziquantel combination product against adult and immature stages of Toxocara cati in cats and kittens after induced infection.

Two studies were performed to examine the efficacy of milbemycin oxime against fourth-stage larvae or adults of Toxocara cati. In the study to determine efficacy against fourth-stage larvae, 20 domestic shorthair cats were inoculated with 500 embryonated eggs. Four weeks after inoculation, the animals were allocated to two groups, and cats in one group were treated with medicated tablets containing 4 mg milbemycin oxime and 10mg praziquantel (MILBEMAX) and cats in the other group with placebo tablets. Seven days after treatment the animals were euthanatized and necropsied for worm counting. The number of worms found was significantly (p=0.0002) lower in cats treated with medicated tablets than in cats treated with placebo tablets. The reduction in the number of worms was 96.53%. In the study to determine efficacy against mature adult worms, 13 kittens were inoculated with T. cati embryonated eggs. On day 45 after inoculation and after the infection had been confirmed through faecal examinations for 11 out of the 13 animals, the 11 infected animals were allocated to two groups and treated as in the first study. Seven days after treatment, all animals were euthanatized and necropsied for worm counting. The number of worms found was significantly (p=0.0043) lower in kittens treated with medicated tablets than in kittens treated with placebo tablets. The reduction in the number of worms was 95.90%. No adverse effects were recorded during either study. It is concluded that the milbemycin oxime-praziquantel tablets that were used are efficacious for the control of T. cati infections in cats.

Aging↗
PubMed2006

Personal assistance, adaptations and participation in students with cerebral palsy mainstreamed in elementary schools.

PURPOSE: The aims of this study were to examine differences in level of participation of students with CP in full inclusion (FI group) as compared to self-contained classes (SC group), differences in the task supports provided for these two groups, the interrelationships between assistance and adaptation provided and the differential impact of physical task supports vs. cognitive/behavioural task supports on participation. METHOD: 148 elementary school students were divided into two groups: 100 fully included (FI) students with CP, and 48 students with CP in self-contained classes (SC). The School Function Assessment (SFA) was used as the main measurement for assessing the levels of participation and functional performance profiles. RESULTS: Statistically significant differences (p < 0.0001) were found between the two groups on all scales (physical and cognitive/behavioural assistance and adaptations). Supports provided to the SC group were significantly greater than to the FI group and physical task supports provided to both groups were significantly greater than cognitive/behavioural supports. Pearson correlations and Smallest Space Analyses (SSA) revealed significant (p < 0.01) moderate to strong correlations (0.57 > r < 0.77) between all four task supports, and between provided task supports and participation (0.66 > r < 0.82). CONCLUSIONS: This study's focus enhances our understanding of the impact of task supports to the various factors contributing to the dimensions of the ICF, as well as their interrelationship with participation. Devises and cognitive and behavioural adaptations are required in a wider manner in addition or alternative to physical assistance by adults if we are to increase the chance of students with severe CP to become participatory for academic and social tasks required in school.

Adaptation, Physiological↗
PubMed2006

Comparative effects of milbemycin oxime-based and febantel-pyrantel embonate-based anthelmintic tablets on Toxocara canis egg shedding in naturally infected pups.

The effect of two treatment programmes on egg shedding in dogs naturally infected with Toxocara canis, one based on a milbemycin oxime-praziquantel-lufenuron combination (SENTINEL) Spectrum; Group 1) and the other based on a febantel-pyrantel embonate-praziquantel combination (DRONTAL) Plus; Group 2), was compared in a study involving 104 suckling pups from three different kennels. The animals in Group 1 were treated at a minimum milbemycin oxime dose of 0.5 mg/kg bw starting at 2 weeks of age and subsequently every 4 weeks until reaching 26 weeks of age. The animals in Group 2 were treated every 2 weeks from week 2 until week 12 of age and then once at week 26 at a minimum febantel and pyrantel embonate dose of 15.0 and 14.4 mg/kg bw, respectively. Toxocara egg counts were determined fortnightly starting at 2 weeks of age and continuing until 26 weeks of age for every pup. Any adverse drug event was recorded during the trial. Both treatment programmes significantly reduced the zoonotic Toxocara egg shedding and were well tolerated by the pups. The pups in Group 1 showed lower average faecal egg counts and were found more frequently shedding no eggs than the pups in Group 2.

Animals↗
PubMed2005

Participation and activity performance of students with cerebral palsy within the school environment.

PURPOSE: The aims of this study were to investigate the levels of participation and activity performance of students with cerebral palsy within the inclusive school context, to explore the relationships between these two aspects of function and to identify predictors of participation among the various school activities. METHOD: Two hundred and forty-eight elementary school students were divided into three groups: 100 fully included (FI) students with CP, 100 matched by class and gender typical students (TS) and 48 students with CP in self-contained classes (SC). The School Function Assessment (SFA) was used as the main measurement for assessing the levels of participation and functional performance profiles. RESULTS: Significant differences (P<0.0001) in levels of participation were evident across the three study groups using MANOVA and ANOVAs analyses, where the TS level was the highest and the SC was the lowest. Comparison of the mean score of the physical and the cognitive/behavioural tasks performance revealed similar results among the three groups. Positive Pearson correlations were obtained between participation and both motor and cognitive/behavioural activity performance in the FI and the SC groups. Regression models for the FI and the SC groups were found significant (P<0.0001) and explained above 69% of the participation variance with physical activity performance as the most predictive variable. CONCLUSIONS: Significant differences exist between participation and activity performance of typical students and students with CP included in regular schools. Moreover, activity performance limitations were found to impact on school participation. These findings stress the continuing need to provide rehabilitative intervention towards removing existing barriers within the inclusive environment.

Activities of Daily Living↗
PubMed2003

Comparative speed of kill between nitenpyram, fipronil, imidacloprid, selamectin and cythioate against adult Ctenocephalides felis (Bouché) on cats and dogs.

Speed of kill and percentage kill of nitenpyram (CAPSTAR) was compared to fipronil (Frontline) spot-on), imidacloprid (Bayvantage/Advantage), selamectin (Stronghold/Revolution) and cythioate (Cyflee) against adult fleas on cats and dogs 3 and 8h post-treatment. Selamectin was used on dogs only; cythioate was used on cats only. Groups of eight cats and eight dogs (four males and four females each) were experimentally infested with 100 unfed fleas 1 day prior to treatment with the test products. One group of cats and one group of dogs served as control. Fleas were collected from four cats and four dogs in each group (two males and two females) by combing 3h after treatment, the remaining four cats or dogs were combed 8h after treatment. In cats cythioate treatment resulted in a mean efficacy of 62.4 and 97.4% at 3 and 8h post-treatment, respectively. Imidacloprid efficacy at the same times was 26.9 and 82.8%, whereas fipronil efficacy was 24.3 and 62.6% efficacy, respectively. In dogs mean efficacy 3 and 8h after treatment with selamectin was 39.7 and 74.4%; with imidacloprid efficacy was 22.2 and 95.7%, respectively and 35.9 and 46.5%, respectively after treatment with fipronil. Nitenpyram was 100% effective in cats and 99.1% effective in dogs within 3h of treatment and 100% effective in cats and dogs within 8h.

Animals↗
PubMed2002

Evaluation of the efficacy of oral lufenuron combined with topical enilconazole for the management of dermatophytosis in catteries.

The efficacy of oral lufenuron, a chitin synthetase inhibitor, combined with topical enilconazole, was evaluated for the management of Microsporum canis infection in 100 cats housed in two catteries in France. The cats were treated with weekly rinses with enilconazole (0.2 per cent) for four weeks and, in each cattery, one group (A) was also treated with micronised griseofulvin (25 mg/kg administered orally twice a day for five weeks) and a second group (B) was treated with 60 mg/kg lufenuron administered orally once on day 0 and again after 30 days. All the cats were examined individually for cutaneous lesions and mycological cultures were made when the treatment began and after 15, 30, 60 and 90 days. In the first cattery, the cats' clinical scores after 30 and 60 days were significantly lower in group B than in group A. In both catteries and both treatment groups, the mean number of fungal colonies decreased rapidly during the first 15 days of treatment, remained stable for the following 45 days but increased from day 60 to the end of the experiment on day 90.

Administration, Cutaneous↗
PubMed2001

Interference dips in the single-crystal absorption spectrum of the ti-mu-fluoro-bis(trifluorochromate(III)) complex.

The lowest energy spin-allowed crystal field band of (Et(4)N)(3)Cr(2)F(9) shows a distinct interference dip at 15,000 cm(-1) with an approximate width of 200 cm(-1). This spectroscopic feature is due to spin-orbit coupling between the (2)E and (4)T(2) excited states and is analyzed with a set of two coupled potential energy surfaces. The minimum of the (4)T(2) potential surface is displaced along at least two normal coordinates. The modes involved cannot be directly determined from the unresolved absorption spectrum, but are obtained from Raman spectra and from the well-resolved spin-forbidden crystal field transition to the (2)A(1) state. The first mode with a frequency of 415 cm(-1) has predominant Cr-F stretching character; the second mode has a frequency of 90 cm(-1) and involves the entire Cr(2)F(9)(3-) dimer.

Journal Article↗
PubMed2001

Ferromagnetic exchange in the ground and (4)A(1) excited states of (Et(4)N)(3)Fe(2)F(9). A magnetic and optical spectroscopic study.

The synthesis, crystal growth, magnetic susceptibility, and polarized optical absorption spectra in the visible and near UV of (Et(4)N)(3)Fe(2)F(9) are reported. From single-crystal magnetic susceptibility data and high-resolution absorption spectra in the region of the (6)A(1) --> (4)A(1) spin-flip transition, exchange splittings in the ground and excited states are derived. Ferromagnetic ground and excited state exchange parameters J(GS) = -1.55 cm(-1) and J(ES) = -0.53 cm(-1) are determined, respectively, and the relevant orbital contributions to the net exchange are derived from the spectra. The results are compared with those reported earlier for the structurally and electronically analogous [Mn(2)X(9)](5-) pairs in CsMgX(3):Mn(2+) (X = Cl(-), Br(-)), in which the splittings are antiferromagnetic. This major difference is found to be due to the increased metal charge of Fe(3+) compared to Mn(2+), leading to orbital contraction and thus to a strong decrease of the orbital overlaps and hence the antiferromagnetic interactions.

Journal Article↗
PubMed2001

Exchange pathways in tris-mu-thiolato-bridged [Cr(2)L(3)](ClO(4)2Cl*H2O*MeOH (L=2,6-bis(aminomethyl)-4-tert-butyl-thiophenolate).

From polarized optical absorption and emission spectra of the tris-mu-thiolato bridged [Cr(2)L(3)](ClO(4))(2)Cl.H(2)O.MeOH (L = 2,6-bis(aminomethyl)-4-tert-butyl-thiophenolate) 1 in the visible and near UV, the exchange splittings of the (4)A(2) ground and the (2)E and (2)T(1) excited states are determined. In view of the large Cr-Cr distance of 3.01 A, the antiferromagnetic ground state splitting with J = 78 cm(-1) (H = J(S(A).S(B))) is large compared to other triply bridged Cr(3+) dimers. This can be rationalized using a model based on a valence bond approach, in which the exchange splittings are derived from configuration interactions between the ground electron configuration and ligand-to-metal (LMCT) as well as metal-to-metal (MMCT) charge-transfer configurations. It allows us to distinguish the interactions via ligand orbitals from the direct interactions between the metal-centered orbitals. We compare our results with those obtained for the tri-mu-hydroxo-bridged [Cr(2)(OH)(3)(tmtame)(2)](NO(3))(3) (tmtame = N,N',N' '-trimethyl-1,1,1-tris(aminomethyl)ethane) 2. In the latter the interactions via the ligands are negligible, whereas they play an important role in 1, due to the softness of the sulfur ligand atoms.

Journal Article↗
PubMed2001

Optical dimer excitations and exchange parameters in (Et4N)3Cr2F9: first observation of the 4A2 --> 2A1 transition.

The synthesis, crystal growth, and polarized optical absorption spectra in the visible and near-UV of (Et4N)3Cr2F9 are reported. In the energy range 25800-27700 cm(-1) the 4A2 --> 2A1 (O notation) ligand field transition can be resolved in detail for the first time in any Cr3+ compound. This allows the determination of the antiferromagnetic ground-state exchange splitting with great accuracy: J = 25.9 cm(-1) and j = 0.27 cm(-1) using the Hamiltonian H = J(S(A).S(B)) - j(S(A).S(B))2, where j leads to deviations from the regular Landé pattern. The temperature dependence of the magnetic susceptibility is nicely reproduced by these parameters. A comparison with Cs3Cr2Cl9 and Cs3Cr2Br9 reveals an exponential dependence of the ground-state splitting upon the Cr-Cr distance in the [Cr2X9]3- dimers. This is the result of a dominant sigma-type orbital exchange pathway along the Cr-Cr axis.

Journal Article↗
PubMed2000

Effects of a new insect growth regulator, CGA-255'728, on the different stages of the cat flea (Siphonaptera: Pulicidae).

A new juvenile hormone mimic CCA-255'728, developed by Novartis, was tested for its efficacy on different life stages of the cat flea, Ctenocephalides felis (Bouché). The compound was mixed in bovine blood at concentrations of 1, 10, and 100 ppb and fed to adult fleas using an artificial membrane system. Less than 7% of the eggs from fleas fed 10 and 100 ppb hatched, compared with >70% hatch in eggs laid by control fleas or fleas fed 1 ppb. Histological studies demonstrated that approximately 50% of the eggs from fleas fed 10 ppb contained unhatched larvae that died after completing embryological development. At 100 ppb, 24% of the fleas died as fully formed larvae within the egg, but at this concentration nearly 20% of fleas also died before embryogenesis was completed. In addition to embryonic and larval mortality, approximately 28% of eggs from the 100 ppb-treated group were deposited as empty shells. Evidently these eggs were crushed by the muscular action of the oviduct and yolk was expelled into the oviduct during oviposition. None of the test concentrations showed adulticidal effects over a 10-d period. Fecundity was significantly increased with increased concentrations of CGA-255'728 indicating that the compound mimicked the effect of juvenile hormone.

Animal Feed↗
PubMed1999

Effect of lufenuron on chorionic and cuticular structure of unhatched larval Ctenocephalides felis (Siphonaptera: Pulicidae).

When adult cat fleas, Ctenocephalides felis (Bouché), were fed concentrations of < or = 0.08 ppm lufenuron in cattle blood, egg hatch did not differ significantly from the controls. However, as the concentration of lufenuron in blood increased from 0.125 to 1.0 ppm egg hatch decreased to 64 and 2%, respectively. Most of these eggs contained fully developed larvae. Microscopic examination of unhatched larvae, revealed that the cuticle epidermal cells, chorion, and vitelline membrane all were affected by lufenuron treatment. Larvae often produced 2 separate cuticles in response to treatment. The 1st cuticle consisted of an indistinct layer of epicuticle and a procuticle composed of randomly deposited chitin microfibrils. After the 1st layer of procuticle separated from the epidermal cells, a 2nd layer of procuticle was deposited. It was not possible to determine whether the egg tooth was functional during larval hatch. The surface of the egg tooth appeared normal, but the cuticle may have had structural abnormalities similar to those seen in other areas of the exoskeleton. Structural defects appeared to be due to the cytotoxic effects of lufenuron. The epidermal cells of treated larvae showed evidence of disintegration (i.e., the nuclei and mitochondria appeared to be degenerating and the amount of endoplasmic reticulum and other cytoplasmic organelles was decreased). The chorion of lufenuron-treated larvae consisted of an outer layer, middle and inner layers that were thinner and less electron dense than those of controls, and lacked the innermost chorionic layer found in the control larvae. The vitelline membrane also was thinner than that of the controls. Larval hatching was prevented by ruptures in the cuticle, which opened during eclosion resulting in the loss of hemolymph and desiccation of the larva. Evidently, tearing of the cuticle was caused by abnormal formation of the procuticle that was not strong enough to withstand the cuticular expansion and muscular movement of the larva within the egg shell.

Animals↗
PubMed1999

Mode of action of lufenuron in adult Ctenocephalides felis (Siphonaptera: Pulicidae).

When cat fleas, Ctenocephalides felis (Bouché), were fed concentrations of lufenuron in cattle blood ranging from 0.5 to 4 ppm, adult mortality increased in a dose-dependent manner to a maximum of approximately 24% over a period of 10 d. Fleas treated with 0.5 ppm produced abnormal endocuticle consisting of protein globules embedded in an amorphous chitin matrix. At concentrations of 1.0 ppm or greater, endocuticle formation was inhibited. Ultrastructural studies demonstrated that inhibition of chitin synthesis was associated with degeneration of the epidermal cells. The amount of epidermal cytoplasm decreased and cytoplasmic organelles including mitochondria, ribosomes, and golgi showed lytic changes. At least some mortality of treated fleas was likely the result of a weakened endocuticle and the corresponding decrease in resiliency of the cuticle to expansion during blood-feeding and egg production. An unexpected result of lufenuron treatment was the inhibition of midgut epithelial cell differentiation. At concentrations of 0.5 and 1.0 ppm, partially differentiated epithelial cells were seen in the midgut of bloodfed fleas along with fully differentiated cells.

Animals↗
PubMed1998

Mode of action of lufenuron on larval cat fleas (Siphonaptera: Pulicidae).

Adult cat fleas, Ctenocephalides felis (Bouché), were fed suboptimal in vitro concentrations of lufenuron in blood to allow hatching of flea larvae for cytological study. At concentrations of 0.125, 0.25, and 0.5 ppm, larval hatch was 64, 15, and 4%, respectively. Larvae hatching from eggs laid by adults fed lufenuron at concentrations of 0.025, 0.08, or 0.125 ppm did not differ significantly from the control. However, many larvae from the 0.08-ppm group and higher concentrations died during the 1st instar. Examination of these larvae revealed that they were dying from desiccation caused by bleeding from microscopic lesions in the cuticle or the inability to complete the molt to the next instar. Electron micrographs showed that lufenuron often disrupted formation of the endocuticle resulting in the deposition of an amorphous mass of randomly oriented chitin microfibrils. Other larvae formed normal endocuticle but were unable to digest the old endocuticle or produce new procuticle after apolysis. Failure of larvae to digest old cuticle or form new cuticle was caused by degeneration of the epidermal cells needed for the synthesis of molting fluid and chitin.

Animals↗
PubMed1980

[Psychology, psychopathology and social problems of children with cystic fibrosis].

The authors examined 33 children aged 7 to 17 years who suffered from cystic fibrosis. This was possible in a holiday camp especially organized for such children. In two or more sessions different tests of performance and projection were made. Furthermore, case histories, the present physical state of the children, the observations of the nursing staff and the answers of the parents to a questionnaire were used as components of the examination. 27 children (88%) showed a moderate or severe psychoreactive disturbance directly related with the disease. There is a connection between the severity of the illness and the degree of the psychoreactive disturbance. 12 children (36%) showed a noticeable to severe psychoorganic disturbance of performance. All psychoorganically disturbed children suffered from a moderate or severe form of cystic fibrosis. 14 children (47%) suffered from further non specific psychoreactive disorders, partially with neurotic or psychosomatic symptoms which are without exception causally related to a disturbed social background. In any case, incidence and even severity of psychopathological findings in children with cystic fibrosis cannot be ignored and must be taken into consideration at the elaboration of a therapeutical plan. Holiday camps with full comprehensive care and control of the cystic fibrosis children are of great importance for them and their parents, especially with regard to the mental hygiene.

Adolescent↗