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Biomedical subjects

G Ruff

Publications and source records attributed to G Ruff.

At least 19 recordsLinked to original sources
PubMed2004

Tuning the scattering length with an optically induced Feshbach resonance.

We demonstrate optical tuning of the scattering length in a Bose-Einstein condensate as predicted by Fedichev et al. [Phys. Rev. Lett. 77, 2913 (1996)]. In our experiment, atoms in a 87Rb condensate are exposed to laser light which is tuned close to the transition frequency to an excited molecular state. By controlling the power and detuning of the laser beam we can change the atomic scattering length over a wide range. In view of laser-driven atomic losses, we use Bragg spectroscopy as a fast method to measure the scattering length of the atoms.

Journal Article↗
PubMed1998

Facial fractures and related injuries: a ten-year retrospective analysis.

A retrospective analysis of 828 patients with significant midface or mandibular fractures was undertaken to illustrate the multisystem nature of traumatic injuries associated with fracture of the facial skeleton, covering the period from 1985 to 1994. Special emphasis was placed on determining associated injuries sustained as well as epidemiological information. The experience presented differs from other large series in the literature in that the predominant mechanism of injury is motor vehicle accidents (67%) rather than assaults. Of the patients reviewed, 89% sustained significant associated injuries. Closed head trauma with documented loss of consciousness was noted most frequently (40%), followed by extremity fractures (33%), thoracic trauma (29%), and traumatic brain injuries (25%). Only 11% of patients sustained facial fractures without concomitant injury.

Accidents, Traffic↗
PubMed1996

Genetic resistance of Creole goats to cowdriosis in Guadeloupe. Status in 1995.

A genetic predisposition to resistance (R)/susceptibility (S) has been demonstrated for cowdriosis in certain goal lines. In order to identify genetic markers of R/S and to follow their transmission to the offspring, 4 groups of sires and dams were crossbred in 1991, 1992, and 1993: Rr, RS, SR, and SS. The offspring were challenged at the age of six months with subsequent challenge of the S parent. From 28 presumed S dams, 7 turned out R and from 2 presumed S sires, 1 was R and the other undefinable. The resistance rate was 76% for 21 RR kids and 45% for 20 RS kids. The R character seems to be better transmitted by dams than the S one. No difference was observed between R and S goats in terms of incubation period and body temperature level after challenge. There was no statistical effect found of sex, litter size, or birth mass on the R/S character; only a slight effect on daily mass gain was observed. Sperm has been collected from 4 S sires (died after challenge) and 5 R sires, and stored in liquid nitrogen in order to conceive additional SR and SS progeny. Several caprine leucocyte antigens seem to be genetic markers of R (Be 1, CLY) and of S (Be 9, Be 22, Be 23). Further powerful tools like microsatellites and probes defining other interesting loci possibly involved in disease pathogenesis are now at hand and will be included in future experiments.

Animals↗
PubMed1996

Soft-tissue fungal infections: surgical management of 12 immunocompromised patients.

Isolated fungal soft-tissue infections are uncommon but may cause severe morbidity or mortality among transplant recipients and other immunosuppressed patients. Twelve immunocompromised patients illustrating three patterns of infection were treated recently at the Duke University Medical Center. These groups comprised (I) locally aggressive infections, (II) indolent infections, and (III) cutaneous manifestations of systemic infection. Patient diagnoses included organ transplant, leukemia, prematurity, chronic obstructive pulmonary disease, and rheumatoid arthritis. Time from immunosuppression to biopsy ranged from 5.5 to 31 weeks. Organisms included Aspergillus, Rhizopus, Fusarium, Paecilomyces, Exophiala, and Curvularia. Patients presented with necrotic ulcerations or nodules. Surgical treatment ranged from radical debridement to excisional biopsy to none. Antifungal chemotherapy also was employed in some cases. The mortality rate was 33 percent, two patients dying without evidence of fungal infection. Six of the eight survivors cleared their infections. Necrotic skin lesions with surrounding erythema in this population call for prompt examination, biopsy, and culture. Group I lesions mandate radical excision with rapid intraoperative microscopic control and systemic antifungal medication. Group II requires surgical control with or without antifungal therapy. Group III requires systemic antifungal therapy for metastatic infection. In our opinion, treatment of fungal soft-tissue infection should be tailored to infection type and requires a team approach of surgeon and expert infectious disease consultation.

Adult↗
PubMed1995

Twenty-year experience with early surgery for craniosynostosis: I. Isolated craniofacial synostosis--results and unsolved problems.

Early surgery for isolated craniosynostosis is designed to improve morphology, to prevent functional disturbances, and equally important, to enhance the psychosocial development of the child. As the first of a two-part series, 104 patients with isolated craniofacial synostosis were retrospectively analyzed. Diagnoses included bilateral coronal (10), unilateral coronal (57), metopic (29), and sagittal synostosis (8). All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 8.1 months). Thirteen percent of patients (14) required a secondary cranial vault operation (mean age 22.6 months) to address residual deficits in craniofacial form. Perioperative complications were minimal (5.0 percent), and there was no mortality. Average length of postoperative follow-up was 46.0 months. By the classification of Whitaker et al., which assesses surgical results, 87.5 percent of patients were considered to have at least satisfactory craniofacial form (category I-II) at latest evaluation. Overall rates of hydrocephalus, shunt placement, and seizures (3.8, 1.0, and 2.9 percent, respectively) were low. Among the isolated craniosynostoses, unilateral coronal synostosis/plagiocephaly poses the most complex problems, including vertical orbital dystopia, nasal tip deviation, and residual craniofacial asymmetry; there is also a wide spectrum of findings and growth patterns in this subgroup.

Craniofacial Dysostosis↗
PubMed1995

Twenty-year experience with early surgery for craniosynostosis: II. The craniofacial synostosis syndromes and pansynostosis--results and unsolved problems.

As the second of a two-part series, 76 patients with pansynostosis and craniofacial synostosis syndromes were retrospectively analyzed. Diagnoses included pansynostosis (7), craniofrontonasal dysplasia (8), and Apert (24), Crouzon (15), and Pfeiffer (15) syndromes. All patients underwent primary fronto-orbital advancement-calvarial vault remodeling procedures at less than 18 months of age (mean 6.1 months). Twenty-eight patients (36.8 percent) required a secondary cranial vault operation (mean age 28.4 months). Additionally, a major tertiary procedure was necessary in 5 patients to deal with persistent unacceptable craniofacial form. To address the associated finding of midface hypoplasia, 64.8 percent (n = 35) of patients underwent Le Fort III midface advancement or had that procedure recommended for them. The remainder were awaiting appropriate age for this reconstruction. The more extensive pathologic involvement of the pansynostosis and craniofacial syndrome group is illustrated. As compared with the isolated craniofacial synostosis group previously reported, the incidence of major secondary procedures (36.8 versus 13.5 percent), perioperative complications (11.3 versus 5.0 percent), follow-up complications (44.7 versus 7.7 percent), hydrocephalus (42.1 versus 3.9 percent), shunt placement (22.4 versus 1.0 percent), and seizures (11.8 versus 2.9 percent) was significantly increased. Complex problems including those of increased intracranial pressure, airway obstruction, and recurrent turricephaly or cranial vault maldevelopment are repeatedly encountered. In addition, that early fronto-orbital advancement-cranial vault remodeling failed to promote midface development and hypoplasia of this region is almost a consistent finding in the craniofacial syndromic group. The average length of postoperative follow-up was 6 years. According to the classification of Whitaker et al., which assesses surgical results, 73.7 percent of patients were considered to have at least satisfactory craniofacial form (category I-II) at latest evaluation. An algorithmic approach to the treatment of all patients with craniosynostosis is presented utilizing early surgical intervention as the key element.

Acrocephalosyndactylia↗
PubMed1994

Antibody reactivity to the immunodominant epitopes of the caprine arthritis-encephalitis virus gp38 transmembrane protein associates with the development of arthritis.

High titers of antibodies to caprine arthritis-encephalitis virus (CAEV) envelope (Env) glycoproteins are found in infected goats developing a progressive arthritis. In order to identify linear B epitopes of the CAEV Env, which may be involved in the immunopathology of arthritis, we constructed a lambda gt11 Env expression library. By combining library screening with sera from naturally infected Swiss goats with an enzyme immunoassay with overlapping peptides (pepscan), four group-specific epitopes could be precisely defined in the transmembrane envelope proteins: TM1 to TM4, including a conserved structure (TM3) that corresponds to the immunodominant epitope of human immunodeficiency virus type 1 and other lentiviruses. A panel of 190 CAEV naturally infected goat serum samples, obtained from animals with defined clinical status, was tested for reactivity to synthetic peptides corresponding to the TM epitopes in an enzyme-linked immunosorbent assay. Antibody reactivity to two epitopes was highly associated (TM3, P = 0.002, and TM4, P < 0.001) with the presence of clinically detectable arthritis. Such an association is absent for anti-Gag antibody. Antibodies to the immunodominant structures of the TM glycoprotein could thus have an important role in the immunopathogenic process leading to disease.

Amino Acid Sequence↗
PubMed1993

The paradox of MHC-DRB exon/intron evolution: alpha-helix and beta-sheet encoding regions diverge while hypervariable intronic simple repeats coevolve with beta-sheet codons.

Twenty-one different caprine and 13 ovine MHC-DRB exon 2 sequences were determined including part of the adjacent introns containing simple repetitive (gt)n(ga)m elements. The positions for highly polymorphic DRB amino acids vary slightly among ungulates and other mammals. From man and mouse to ungulates the basic (gt)n(ga)m structure is fixed in evolution for 7 x 10(7) years whereas ample variations exist in the tandem (gt)n and (ga)m dinucleotides and especially their "degenerated" derivatives. Phylogenetic trees for the alpha-helices and beta-pleated sheets of the ungulate DRB sequences suggest different evolutionary histories. In hoofed animals as well as in humans DRB beta-sheet encoding sequences and adjacent intronic repeats can be assembled into virtually identical groups suggesting coevolution of noncoding as well as coding DNA. In contrast alpha-helices and C-terminal parts of the first DRB domain evolve distinctly. In the absence of a defined mechanism causing specific, site-directed mutations, double-recombination or gene-conversion-like events would readily explain this fact. The role of the intronic simple (gt)n(ga)m repeat is discussed with respect to these genetic exchange mechanisms during evolution.

Alleles↗
PubMed1993

The use of particulate hydroxyapatite and plaster of Paris in aesthetic and reconstructive surgery.

The authors describe their early investigative results of using a mixture of hydroxyapatite (HA) and plaster of Paris (PP) in skull and frontal sinus defects in a large series of cats. Histologically, bone was found to form and infiltrate the HA-PP implant over a period of months, with gradual resorption of the plaster in 6-8 weeks. Clinically, the HA-PP combination has been used in 24 patients over the past seven years for various skull, zygomatic, and mandibular defects.

Adult↗
PubMed1993

Use of isoelectric focusing to define major histocompatibility complex class I polymorphism in goats.

We have used biochemical methods to extend and improve serological class I typing using a panel of 77 Swiss goats of the Saanen breed, comprising dam-offspring combinations from six half-sib sire families and several unrelated animals. Of these animals class I molecules were precipitated from cell lysates with the mAb B1.1G6 and HC10. Immunoprecipitates were analysed by SDS-PAGE and 1D-IEF. There was a good agreement between class I serological types and IEF banding patterns. We have identified three new class I specificities and subdivided the Be17 specificity. IEF has enabled us to make planned immunizations to produce antisera to the new specificities. New evidence for the expression of a second class I locus product in the Be7 haplotype has been found.

Animals↗
PubMed1993

Serological and biochemical detection of B-cell antigens in goats.

The production of B-cell specific alloantisera by lymphocyte transfusion between class I matched, MLR positive goats is described. Furthermore, the usefulness of preceding IEF typing is demonstrated in the selection of immunization pairs. After suitable absorptions and cluster analysis the detected B-cell specific antigens were designated BeD1-BeD6. The specificity BeD3 could also be detected by two class II-specific murine anti-H2 monoclonal antibodies. IEF class II typing of 34 animals gave concordant results between the two techniques. One additional allelic variant could be detected by IEF typing. The detected products segregated in close linkage to the earlier described caprine class I antigens. One recombinant has been found in 78 offspring. The reactivity of cells in mixed lymphocyte cultures (MLC) was correlated with the compatibility of the test cells for their B-cell specific antigens. Three of the B-cell specific sera were characterized by immunoprecipitation. The precipitated antigens corresponded in molecular weight to MHC class II products as described in other species indicating that the here described caprine products are of class II nature.

Animals↗
PubMed1993

Occurrence of caprine leucocyte antigens (CLA) in Creole goats susceptible/resistant to heartwater.

A genetic predisposition to the manifestation of disease symptoms has been demonstrated for heartwater in certain goat lines. In order to clarify a possible involvement of the major histocompatibility complex (MHC) in the pathogenesis of heartwater, over 100 Creole goats have been typed serologically for their CLA class I antigens coded by the caprine MHC. The MHC is a genetic system that influences different immunological processes, i.e. the individual immune response. With our alloantisera we were able to detect 13 different CLA alleles also present in the Swiss breeds, two non-MHC antigens, a new cluster defined by the splitting of two antigens and several specific reaction patterns of single reagents. The allele frequencies of the detected CLA antigens differed for the resistant and susceptible groups examined. Whether the differences represent regional sire effects or indicate pathogen-induced selection pressure remains to be clarified. Additional testing of resistant/susceptible goats originating from common environment as well as of specially crossbred (resistant x susceptible) animals are underway.

Animals↗
PubMed1992

Activation of alpha 1- and alpha 2-adrenoceptors inhibits noradrenaline release in rabbit renal arteries: effects of pertussis toxin and N-ethylmaleimide.

1. The effects of selective alpha 1- and alpha 2-adrenoceptor agonists and antagonists on the stimulation-induced (S-I) outflow of radioactivity at 2 Hz were investigated in superfused rabbit renal arteries incubated with [3H]-noradrenaline. 2. The alpha 1-adrenoceptor agonist methoxamine (10 microM) inhibited S-I outflow of radioactivity and this effect was abolished by the alpha 1-adrenoceptor antagonist prazosin (0.1 microM) but not by the alpha 2-adrenoceptor antagonist rauwolscine (1 microM). Neither the prostaglandin synthesis inhibitor indomethacin (10 microM) nor the adenosine receptor antagonist 8-phenyl-theophylline (1 microM) prevented the inhibitory effect of methoxamine. 3. The alpha 2-adrenoceptor agonists clonidine (0.1 microM) and UK 14304 (0.1 microM) both inhibited S-I outflow of radioactivity. The inhibitory effect of clonidine was blocked by rauwolscine but not by prazosin. The inhibitory effect of UK 14304 was markedly reduced by rauwolscine. 4. Prazosin (0.1 microM) alone did not enhance the S-I outflow of radioactivity at 2 Hz and slightly enhanced S-I outflow at 4 Hz. Rauwolscine (1 microM) alone markedly enhanced S-I outflow of radioactivity at 2 and 4 Hz. 5. Pretreatment of the arteries with pertussis toxin (1 microgram ml-1) did not significantly alter the inhibitory effects of methoxamine or UK 14304 or the potentiation by rauwolscine. However, pretreatment of the arteries with a higher concentration of pertussis toxin (5 micrograms ml-1) prevented the inhibitory effect of methoxamine but still did not affect the responses to UK 14304 and rauwolscine. 6. Pretreatment of the arteries with N-ethylmaleimide (NEM, 10 microM) for 30 min did not alter the inhibitory effect of methoxamine but markedly attenuated the inhibitory effect of UK 14304 and the facilitatory effect of rauwolscine. 7. The results suggest that both alpha 1- and alpha 2-adrenoceptors take part in the modulation of noradrenaline release from sympathetic nerves in rabbit renal arteries. Alpha 1-adrenoceptor mediated inhibition may be coupled to G-proteins which are pertussis toxin sensitive and alpha 2-adrenoceptor mediated inhibition to G-proteins which are NEM-sensitive.

Adrenergic alpha-Agonists↗
PubMed1991

Alpha 2-adrenoceptor activation inhibits noradrenaline release in human and rabbit isolated renal arteries.

The aim of the present study was to investigate alpha 2-adrenoceptor modulation of noradrenaline release in superfused strips of human and rabbit renal arteries. The arteries were field-stimulated after incubation with [3H]noradrenaline. The stimulation-induced outflow of radioactivity was taken as an index of noradrenaline release. At a high stimulation frequency (4 Hz), the alpha 2-adrenoceptor agonist clonidine (0.1 mumol/l) failed to inhibit stimulation-induced outflow of radioactivity in human and rabbit renal arteries whereas the alpha 2-adrenoceptor agonist UK 14304 (0.1 mumol/l) did inhibit stimulation-induced outflow. The inhibitory effect of UK 14304 in human renal arteries was blocked by the alpha 2-adrenoceptor blocking drug rauwolscine (1 mumol/l). At a lower stimulation frequency (2 Hz), both clonidine and UK 14304 inhibited stimulation-induced outflow of radioactivity from rabbit renal arteries; both effects were blocked by rauwolscine. Rauwolscine by itself enhanced stimulation-induced outflow of radioactivity in both preparations. The results suggest that activation of prejunctional alpha 2-adrenoceptors in human and rabbit renal arteries inhibits noradrenaline release. Neuronally released noradrenaline exerts inhibitory feed-back modulation of its own release through activation of prejunctional alpha 2-adrenoceptors. At a higher stimulation frequency most of the prejunctional alpha 2-adrenoceptors are already occupied by endogenous noradrenaline and clonidine fails to inhibit noradrenaline release since it seems to act as a partial agonist at these prejunctional alpha 2-adrenoceptors.

Adrenergic alpha-Agonists↗
PubMed1991

Production of alloantibodies against bovine B-lymphocyte antigens.

A series of alloimmunizations were carried out between BoLA class I antigen typed bulls, with the aim of generating class II specific reagents. Of the antisera produced, seven demonstrated exclusively B cell reactivity. Another 19 sera reacted with both T and B cells from some animals and with B cells only in other cases. Suitable buffy coat absorptions removed T cell reactivity from some sera and shortened broader reactivities in certain B cell specific sera. Typing of separated T and B cells from related and unrelated animals permitted clustering of the sera into four groups. These groups behave as allelic specificities. The class II nature of the recognized structures was strongly indicated by two further pieces of evidence. The presence or absence of particular B cell antigens correlated with reactivity of cells in one-way mixed lymphocyte cultures. In addition, a number of the B cell specific sera were characterized by immunoprecipitation of radiolabelled lymphocytes. The precipitated products corresponded in molecular weight to alpha and beta chains of MHC class II dimers, as has been found in this and other species.

Animals↗
PubMed1989

A comparison of lymphocyte antigen specificities in Norwegian and Swiss goats.

In all, 363 alloantireagents were tested in Berne, Switzerland and in Oslo, Norway against lymphocytes from 1679 goats of different breeds. The same lymphocytotoxicity test was used at both laboratories. The test data were pooled, and correlation coefficients for pairs of sera were used to group the sera in clusters. Twelve clusters were accepted as defining lymphocyte antigen specificities believed to be coded by genes within the major histocompatibility complex (MHC). The specificities defined by these clusters were designated Eu1-Eu12. Two clusters defined specificities which were not coded from loci within the MHC. These were designated GLY-1.1 and GLY-2.1, and the loci GLY-1 and GLY-2, respectively. GLY-1.1 was also located on erythrocytes.

Animals↗