Peri-implant bone loss around platform-switched Morse taper connection implants: a prospective 60-month follow-up study.

The aim of this study was to measure the crestal bone level changes at 60 months of follow-up and to evaluate the influence of biologically relevant, anatomical, and implant-related variables. A prospective study design was used. STROBE guidelines were followed. A total of 576 implants were inserted in 270 patients needing an implant-supported, partial, fixed dental prosthesis or a single crown. Standardized peri-apical radiographs were obtained at 2 months (time of implant-abutment connection and prosthetic loading) and 60 months of follow-up. Descriptive statistics were used and inter- and intra-examiner reliability determined. A mixed model was used to evaluate the predictor variables. The correlation among multiple implants inserted in a single patient was considered. Significance was assessed using the type 3 test. Sensitivity analyses, least-squares means analyses, t-tests, and χ2 tests were also conducted. The statistical analysis was performed at the implant level; P<0.05 indicated statistical significance. At the 60-month follow-up, the mean marginal bone remodelling was -0.59±1.34mm (range -5.70 to 3.65mm). Marginal bone loss was significantly influenced by implant depth, implant location, and the interactions implant depth×jaw, implant location×timing of implant placement, and jaw×implant diameter. At the 60-month follow-up, a low mean marginal bone loss was found, which was significantly higher with subcrestal implants and anterior implants.

Physiology and Endocrinology Symposium: heat shock proteins: potentially powerful markers for preimplantation embryonic development and fertility in livestock species.

For the mammalian embryo to successfully complete development, it must not only incur proper timing of internal machinery, but also protect itself from potentially harmful external stimuli. These stimuli, ranging from chemical to temperature flux, can result in defects in processes regulating gamete production and quality, as well as early embryonic development. To counterbalance these potential detriments, the mammalian cell has complex machinery consisting of heat shock factors and proteins that prevent protein misfolding and malfunction. Heat shock protein (HSP) genes have become a growing topic to understand the mechanisms of successful gamete formation and embryonic development, critical factors for livestock fertility. In addition, HSP have become a focus in understanding how external stimuli during the in vitro embryo production process may have a developmental impact. To further elucidate these mechanisms, it has become a necessity for more in-depth functional studies on HSP using technologies such as RNA interference and antibody use during embryo culture. Through these studies we can gain a more comprehensive perspective of HSP function and importance during early development. In addition, information from these studies may provide critical markers for improved fertility and development.

Differential expression of heat shock protein genes and their splice variants in bovine preimplantation embryos.

Heat shock proteins (HSP) are among the first proteins produced during embryonic development and are crucial to cell function; their activities include folding, unfolding, transport, and localization of proteins and differentiation and regulation of the embryonic cell cycle. Although HSP have been extensively studied in humans and mice, limited information exists on the roles of these genes in bovine embryos. As such, the objectives of this study were to profile the expression of HSP and their splice variants in bovine embryos (degenerates vs. blastocysts) and to carry out association analysis with fertility traits. Quantitative real time PCR analysis revealed differences in expression that ranged from 1.5- to 7.6-fold in degenerate embryos compared with blastocysts. Interestingly, all members of the HSP40 family were found to be upregulated in degenerate embryos. Analysis of current bovine Ensembl data showed that 13 HSP genes have 1 transcript each, 2 genes have 2 transcripts each, and 2 have 3 transcripts each. Some splice variants show differential expression between degenerate embryos and blastocysts, whereas others were not expressed at all in embryos, which implies different functions of these transcripts in embryonic development. The most significant differentially expressed genes were further investigated for association with fertility and development traits. Single nucleotide polymorphisms in DNAJC15 and DNAJC27 were found to be associated with blastocyst rate and fertilization rate, respectively. Collectively, the roles of HSP in fertilization and early development of cattle embryos are important.

Short communication: expression and alternative splicing of POU1F1 pathway genes in preimplantation bovine embryos.

Early embryo loss is a major contributing factor to cow infertility and that 70 to 80% of this loss occurs between d 8 and 16 postfertilization. However, little is known about the molecular mechanisms and the nature of genes involved in normal and abnormal embryonic development. Moreover, information is limited on the contributions of the genomes of dams and of embryos to the development and survival of preimplantation embryos. We hypothesized that proper gene expression level in the developing embryo is essential for embryo survival and pregnancy success. As such, the characterization of expression profiles in early embryos could lead to a better understanding of the mechanisms involved in normal and abnormal embryo development. To test this hypothesis, 2 d-8 embryo populations (degenerate embryos and blastocysts) that differed in morphology and developmental status were investigated. Expression levels of POU1F1 pathway genes were estimated in 4 sets of biological replicate pools of degenerate embryos and blastocysts. The OPN and STAT5A genes were found to be upregulated in degenerate embryos compared with blastocysts, whereas STAT5B showed similar expression levels in both embryo groups. Analysis of splice variants of OPN and STAT5A revealed expression patterns different from the total expression values of these genes. As such, measuring expression of individual transcripts should be considered in gene expression studies.

Absorptive capacity as a guiding concept for effective public sector management and conservation of freshwater ecosystems.

The ability of an organisation to recognise the value of new external information, acquire it, assimilate it, transform, and exploit it, namely its absorptive capacity (AC), has been much researched in the context of commercial organisations and even applied to national innovation. This paper considers four key AC-related concepts and their relevance to public sector organisations with mandates to manage and conserve freshwater ecosystems for the common good. The concepts are the importance of in-house prior related knowledge, the importance of informal knowledge transfer, the need for motivation and intensity of effort, and the importance of gatekeepers. These concepts are used to synthesise guidance for a way forward in respect of such freshwater management and conservation, using the imminent release of a specific scientific conservation planning and management tool in South Africa as a case study. The tool comprises a comprehensive series of maps that depict national freshwater ecosystem priority areas for South Africa. Insights for implementing agencies relate to maintaining an internal science, rather than research capacity; making unpublished and especially tacit knowledge available through informal knowledge transfer; not underestimating the importance of intensity of effort required to create AC, driven by focussed motivation; and the potential use of a gatekeeper at national level (external to the implementing organisations), possibly playing a more general 'bridging' role, and multiple internal (organisational) gatekeepers playing the more limited role of 'knowledge translators'. The role of AC as a unifying framework is also proposed.

Short communication: Effects of the progesterone receptor variants on fertility traits in cattle.

The progesterone receptor (PGR) gene is a key factor in the initiation and maintenance of pregnancy and in embryo development. Currently, it is unknown what variants of the PGR gene are related to fertility traits in cattle. Identification of such variants would allow the implementation of marker-assisted selection in breeding schemes. The objective of this study was to investigate the association of single nucleotide polymorphisms (SNP) of PGR with fertility traits in Holstein dairy cattle. An in vitro fertilization system was used to maximize the efficiency of the identification of genetic factors affecting fertility. This in vitro fertilization system would allow the assessment of fertilization and embryonic survival rates independently of influences from the uterine environment. A total of 5,566 fertilization attempts were performed, and a total of 3,679 embryos were produced using oocytes from 324 Holstein cows and semen from 10 Holstein bulls. Sequencing of pooled DNA samples from ovaries revealed an SNP (G/C) in intron 3 of PGR. A generalized linear model was used to analyze the association of this SNP with fertilization and embryonic survival rates for each ovary. Oocytes obtained from CC ovaries showed a 61% fertilization rate, compared with 68 and 69% for GC and GG ovaries, respectively. The survival rate of embryos produced from GG ovaries was 5 and 6% higher than that of GC and CC ovaries . These results indicate that the PGR SNP could be used in marker-assisted selection breeding programs in Holstein dairy cattle.

A technique for pelvic radiography in the standing horse.

REASONS FOR PERFORMING STUDY: An alternative technique of radiographing the pelvis in the standing horse is required, to avoid the risks associated with general anaesthesia. HYPOTHESIS: That lateral oblique radiography in the standing horse would be a useful technique in the investigation of pelvic injury. OBJECTIVES: To describe the technique of lateral oblique pelvic radiography in the standing horse and demonstrate the feasibility and usefulness of this technique. METHODS: A technique for lateral oblique radiography in the standing horse was devised and retrospective review made of radiographic findings in 18 clinical cases. RESULTS: The caudal iliac shaft, greater trochanter of the femur, femoral head, acetabulum and coxofemoral articulation on the side under investigation were visualised consistently using this technique. Of the 18 cases, 3 iliac shaft fractures, 1 acetabular fracture, 2 coxofemoral luxations and 4 horses with new bone formation around the coxofemoral joint and/or proximal femur were identified. CONCLUSIONS: Lateral oblique radiography in the standing, conscious horse can be used to investigate conditions affecting the caudal iliac shaft, coxofemoral articulation and proximal femur in the horse. POTENTIAL RELEVANCE: The technique is straightforward, noninvasive and useful in the investigation of horses with suspected pelvic injury. However, not all pelvic injuries would be identified, and normal radiographic findings do not rule out injury or fractures elsewhere in the pelvis.

Ultrasonography of the medial palmar intercarpal ligament in the Thoroughbred: technique and normal appearance.

REASONS FOR PERFORMING STUDY: Tearing of the medial palmar intercarpal ligament (MPICL) has been recognised as a cause of lameness in the Thoroughbred, but diagnosis is difficult due to the nonspecific clinical signs, and can be achieved only by performing arthroscopy on the mid carpal joint (MCJ). It would be beneficial to be able to image the MPICL using ultrasonography to determine whether pathology is present in the ligament in order to aid diagnosis and prognosis. OBJECTIVES: To determine whether the MPICL could be imaged using ultrasound from the dorsal aspect of the MCJ, and to describe the technique and normal ultrasonographic appearance of the ligament. METHODS: A pilot study was performed using 2 cadaver carpi. Each carpus in turn had the MPICL imaged simultaneously using arthroscopy and ultrasound, with a metallic probe positioned on the dorsal aspect of the ligament to highlight the position of the MPICL. Six further pairs of carpi had the MPICL imaged ultrasonographically followed by dissection of the carpus to evaluate the ligament and relate its anatomy to the ultrasound images. Finally, 15 Thoroughbreds with no history of lameness isolated to the carpus had their MPICLs assessed and measured ultrasonographically. RESULTS: The MPICL could be imaged via the dorsal aspect of the MCJ using standard ultrasound equipment. The body and division into medial and lateral branches could be seen as a distinct, moderately dense granular echogenic structure in the palmar aspect of the joint, with clearly defined margins. CONCLUSIONS: The normal MPICL can be imaged reliably using ultrasound in the Thoroughbred from the dorsal aspect of the MCJ. There is a wide range in the normal width of the lateral aspect of the MPICL, but there is good symmetry between contralateral limbs. POTENTIAL RELEVANCE: This report of the normal ultrasonographic appearance of the ligament will be beneficial in acting as a reference for the detection of pathology using ultrasound.

Measuring central executive functioning: what's in a reading span?

Although variations of Daneman and Carpenter's (1980) Reading Span Test (RST) have seen increasing use in both cognitive and neuropsychological research, the specific mental operations involved in performing it remain unclear. We tested 80 undergraduates to examine the extent to which speed of processing, manipulation capacity, and susceptibility to interference contributed to RST performance. The results suggest that, rather than unitary central executive or processing speed functions underlying RST performance, at least two factors, manipulation capacity and susceptibility to interference, underlie the task. Further study of RST operations may lead to a better understanding of the nature of the central executive itself.

Age-related changes in reactive oxygen species production in rat brain homogenates.

The generation of reactive oxygen species (ROS) and resultant oxidative stress have been implicated in the mechanism of brain dysfunction due to age-related neurodegenerative diseases or exposure to environmental chemicals. We have investigated intrinsic age-related differences in the ability of the various brain regions to generate ROS in the absence and presence of Fe(2)+. ROS production in crude brain homogenates from adult rats was linear with respect to time and tissue concentration, and was stimulated to a greater extent by Fe(2)+ than was TBARS production. ROS production was then determined in homogenates from cerebral cortex, striatum, hippocampus, and cerebellum of 7-day-old, 14-day-old, 21-day-old, adult (3-6-month old), and aged (24-month-old) rats using the fluorescent probe 2',7'-dichlorodihydrofluorescin (DCFH). Basal levels of ROS production were similar in 7-, 14-, and 21-day olds, increased in adults, and highest in aged rats, and did not differ between brain regions. ROS production was stimulated by Fe(2)+ (0. 3-30 microM) in a concentration-dependent manner in all brain regions. However, the stimulation of ROS production by Fe(2)+ varied with age. ROS production was greater in 14- and 21-day-old rats compared with adult and aged animals. ROS production in 7-day-old rats was decreased at low Fe(2)+ concentrations and increased at high Fe(2)+ concentrations compared to adult and aged rats. These data show that brain homogenates from neonatal rats respond differently to Fe(2)+, and suggest that developing animals may be more sensitive to oxidative stress in the brain after exposure to toxicants. Published by Elsevier Science Inc.

Pericardial fluid adenosine in ischemic and valvular heart disease.

Adenosine released by ischemic myocardial cells stimulates coronary artery vasodilation. Measurement of adenosine concentrations in pericardial fluid in animal models of myocardial ischemia has been used to study the process of adenosine release. To determine whether pericardial fluid adenosine concentrations are increased in human ischemic heart disease, adenosine concentrations were measured in pericardial fluid in 23 subjects undergoing open-heart surgery for coronary artery disease. The results were compared with adenosine concentrations measured in pericardial fluid obtained from 20 subjects undergoing surgery for valvular heart disease. Adenosine concentrations also were measured in pleural fluid obtained during internal mammary artery bypass grafting. Adenosine concentrations were significantly increased in subjects with coronary artery disease compared with fluid obtained from subjects with valvular heart disease (2.47 +/- 0.24 vs 1.36 +/- 0.21 [SEM] microM [p = 0.0013]). Adenosine concentrations were higher in pleural fluid than pericardial fluid from the same individuals. Adenosine concentrations were significantly correlated with pericardial fluid cell counts and lactate dehydrogenase concentrations (r = 0.48; p = 0.0012 and r = 0.77, p = 0.0001, respectively). The results are consistent with myocardial release of adenosine in ischemic heart disease. If adenosine concentrations in pericardial fluid approximate those in myocardial interstitial fluid, sufficient adenosine is present to stimulate adenosine receptor activation in coronary artery smooth muscle.

Adenosine in bronchoalveolar lavage fluid in asthma.

The inhalation of nebulized adenosine causes bronchoconstriction in asthmatics. In order to explore whether endogenously produced adenosine may contribute to the pathophysiologic aspects of asthma, we measured adenosine concentrations in bronchoalveolar lavage (BAL) fluid in seven subjects with asthma, eight asymptomatic cigarette smokers, and eight normal subjects. The mean concentration of adenosine in BAL fluid from the normal subjects was 0.72 +/- 0.16 microM. Subjects with asthma and cigarette smokers had significantly increased concentrations of adenosine in BAL fluid, 2.55 +/- 0.50 and 1.89 +/- 0.50 microM, respectively. Corrected for the dilution that occurs as a result of the lavage procedure, mean epithelial lining fluid adenosine concentrations were 60 +/- 13 microM in normal subjects, 193 +/- 58 microM in asthmatics, and 155 +/- 56 microM in smokers. Adenosine concentrations were positively correlated with the protein content of the lavage fluid (r = 0.79). Inhalation of nebulized adenosine in the subjects with asthma provoked a 20% reduction in lung function at concentrations 4- to 195-fold higher than was present in the epithelial lining fluid of the same individuals. The presence of increased BAL adenosine concentrations in asthmatics and in cigarette smokers suggests that adenosine may be a nonspecific marker for inflammation in the lung. The demonstration of physiologically relevant concentrations of adenosine in airway fluids of subjects with bronchial hyperreactivity to inhaled adenosine provides evidence for a role of endogenous adenosine in provoking bronchoconstriction in asthma.

Distribution and structure of cloned P elements from the Drosophila melanogaster P strain pi 2.

P transposable elements of Drosophila melanogaster cloned from the strong P strain pi 2 have been analysed. The structures and chromosomal locations of 26 of the 30-50 elements estimated to be present in pi 2 have been determined. At one location two elements are inserted 100 base pairs (bp) apart, and in a second location two elements are only separated by the 8 bp duplicated upon P-element insertion. In addition to 2.9 kilobase-pair (kbp) elements, elements with 14 different internal deletions from 1.3 to 2.3 kbp in size have been isolated. There are 7 copies of the 2.9 kbp element, 2 copies each of 5 internally deleted elements and a single copy of 9 internally deleted elements. One of the elements found twice is the KP element, which may play a role in the regulation of hybrid dysgenesis in strains which contain many copies of this element. Apart from internal deletions the elements are extremely homogeneous in DNA sequence, with only 2 single base polymorphisms detected twice each in over 16 kbp of P-element sequence. Although transpositions are infrequent in an inbred P cytotype strain such as pi 2, the distribution of these cloned elements indicates that when the genomic library was made, the strain was polymorphic with respect to element location. The distribution and structures of the element are discussed with respect to models for regulation of P-element transposition.

Heimlich valve treatment of Pneumocystis carinii-associated pneumothorax.

Two patients were treated for AIDS-associated bilateral pneumothoraces which persisted despite prolonged chest tube drainage. Heimlich flutter valves were used to facilitate the outpatient management of these patients.

Bronchial challenge with adenosine causes the release of serum neutrophil chemotactic factor in asthma.

In order to investigate the mechanism of adenosine-induced bronchoconstriction in asthma, serum neutrophil chemotactic activity (NCA) was measured in normal individuals and patients with asthma before and 5 min after bronchoprovocation testing with adenosine. Challenge testing was terminated when the FEV1 fell by 20% or a concentration of 10 mg/ml was reached. Participants were separated into three groups: six asthmatics hyperresponsive to adenosine (Group 1), seven asthmatics hyperresponsive to histamine but not adenosine (Group 2), and six normal subjects (Group 3). The mean percentage increase in NCA was 84% for Group 1 (p less than 0.001), 29% for Group 2 (p less than 0.05), and only 13% for Group 3. No significant increase in NCA was observed after histamine challenge in seven individuals with asthma derived from Groups 1 and 2. Four patients from Group 1 were rechallenged after treatment with therapeutic doses of oral theophylline. Theophylline therapy was associated with a significant attenuation of the increase in NCA at the concentration of adenosine which caused a 20% decrease in FEV1 before treatment (18% versus 84%, p less than 0.01). The concentration of adenosine which caused a 20% drop in FEV1 was increased at least twofold for each of the four patients. Analysis of NCA by gel filtration chromatography demonstrated an increase in a high molecular weight neutrophil chemotactic factor in the serum of two Group 1 patients after adenosine challenge. Release of a high molecular weight neutrophil chemotactic factor is consistent with a mast cell source for inflammatory mediators in adenosine-induced bronchoconstriction. The therapeutic effects of theophylline, a potent adenosine antagonist, in asthma may therefore occur in part through the inhibition of this process.

DNA sequence of the Doc retroposon in the white-one mutant of Drosophila melanogaster and of secondary insertions in the phenotypically altered derivatives white-honey and white-eosin.

We analysed the structure of the white locus of Drosophila melanogaster in a family of related white mutants. The white-one mutant has bleach white eyes, and a Doc transposable element is inserted into the promotor region of the white locus. The DNA sequence of this Doc insertion was determined, and showed it to be closely related to other Drosophila melanogaster retroposons such as the I factor and the F, G and jockey elements. There are two long open reading frames, which encode a putative nucleic acid binding protein and a putative reverse transcriptase, respectively. Two independent, partially pigmented derivatives were analysed by cloning sequences from this region. In white-honey a transposable element of the retroviral class, B104, is inserted within the Doc element. In white-eosin there is an insertion within the Doc element of a 190 bp sequence that appears to be a member of a novel family of transposable elements. This pogo element is of the same structural class as the Drosophila melanogaster P and hobo elements. These data are consistent with the hypothesis that the Doc retroposon cannot excise, and that, for the white-one mutation, flies with altered phenotypes are most often generated by the insertion of additional transposable elements.

Intravenous streptomycin.

Streptomycin is an effective drug for the treatment of tuberculosis. It is currently recommended for use only by the intramuscular route. This method of drug delivery is accompanied by considerable pain which is unacceptable to many patients. With the advent of many improvements in intravenous therapy that have occurred in the past 40 years, reevaluation of the intravenous use of this drug is warranted. We describe the short-term use of intravenous streptomycin in four patients with pulmonary tuberculosis.

Structural analysis of Doc transposable elements associated with mutations at the white and suppressor of forked loci of Drosophila melanogaster.

DNA sequences from two spontaneous mutations of Drosophila melanogaster associated with insertion of a Doc transposable element have been cloned. In white-one, the element is inserted in the white locus close to where transcription initiates. In a lethal allele of suppressor of forked, su(f)S2, the element is inserted within the transcription unit in the protein coding region. Four other Doc elements have been cloned from a wild-type strain. Doc is a member of the class of transposable elements known as retroposons, which includes the D. melanogaster F, G, Jockey, and I elements. There is no sequence homology between the ends of the Doc element. The 3' or right end terminates with a polyadenylation signal sequence followed by a stretch of oligo-A. The length of the oligo-A varies between elements, and a duplication of variable size is found as a direct repeat flanking inserted Doc elements. Members of the family are conserved at the 3' end, but may be truncated at the 5' or left end. These structural features suggest a mechanism of transposition via an RNA intermediate.

Expression of histamine H1 receptors on cultured histiocytic lymphoma cells.

Histamine H1 receptors were identified in U937 human histiocytic lymphoma cells using a radioligand binding technique with [3H]mepyramine. Reversible high-affinity binding with this ligand was obtained, and specificity of binding for selected H1 agonists and antagonists was demonstrated. Competition binding experiments with mepyramine and histamine yielded results consistent with single-site binding for mepyramine and two-site binding for histamine. Dissociation constants for the high- and low-affinity histamine binding states were 6.8 X 10(-6) and 2.4 X 10(-4) M respectively. The high-affinity state for histamine binding was abolished when the membranes were coincubated with 100 microM guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S). Saturation binding studies yielded an average of 66 fmol/mg protein binding sites (6000 receptors per cell) with a [3H]mepyramine KD of 9.6 nM. When differentiation of these cells was induced by phorbol-myristate-acetate, receptor density increased by 73% to 114 fmol/mg protein. This increase in receptor density was inhibited by actinomycin D and cycloheximide. Exposure of native and differentiated U937 cells to 10(-5) and 10(-4) M histamine for 24 hr resulted in a dose-dependent down-regulation in receptor density. The data indicate that U937 cells may provide a model cell line for the study of histamine receptor gene expression.

Bilateral diaphragm paralysis treated with cuirass ventilation.

The therapeutic effects of cuirass ventilation were studied in two patients with bilateral diaphragm paralysis. Negative inspiratory and positive expiratory pressure applied to the cuirass shell was transmitted to the abdominal and thoracic cavities. Diaphragm excursion was enhanced. Nocturnal cuirass ventilation appears to be an ideal treatment for bilateral diaphragm paralysis.