Effects of ensiling time on corn silage neutral detergent fiber degradability and relationship between laboratory fiber analyses and in vivo digestibility.

Accurate analysis of degradability of silage neutral detergent fiber (NDF) is important for diet formulation and to predict lactational performance of dairy cows. In this study, 5 corn silage hybrids ensiled for 0 (unfermented), 30, 60, 120, and 150 d were used to determine the effects of ensiling time on silage neutral detergent fiber degradability (NDFD) and to assess the relationships between near-infrared reflectance spectroscopy (NIR) NDF-related analyses and in situ NDFD variables. In addition, the relationships between dietary concentration of indigestible NDF, 288-h incubation (iNDF288), or undegraded NDF, 240-h incubation (uNDF240), and in vivo total-tract apparent organic matter and NDF digestibility were studied in total mixed ration samples from 16 experiments with lactating dairy cows. Ensiling time had no effect on silage NDF concentration; however, the ratio of acid detergent fiber ÷ NDF increased, and estimated hemicellulose concentration decreased quadratically with ensiling time. Also, concentration of NDF-bound protein decreased, and that of lignin increased linearly with ensiling time. These changes in silage fiber composition resulted in a linear decrease in in situ effective degradability of silage NDF with increasing ensiling time. The indigestible fraction of NDF and concentration of structural carbohydrates were not affected by ensiling time. Correlations of in situ NDFD variables with laboratory NIR NDFD analyses were weak to moderate. The relationship of corn silage uNDF240 with lignin concentration or 30-h NDFD (all NIR analyses) was remarkably good (R2 = 0.73 and 0.88, respectively). The relationship between in situ iNDF288 concentration (but not uNDF240) and in vivo total-tract apparent digestibility of dietary organic matter and NDF was good (R2 = 0.72 and 0.80, respectively). In conclusion, in situ degradability of silage NDF linearly decreased from 0 to 150 d ensiling time, primarily caused by a decrease in concentrations of hemicellulose and NDF-bound protein. In situ NDF degradability measurements and common laboratory NIR NDF-related analyses were generally poorly correlated. We found a good relationship between in vivo NDF digestibility and dietary concentration of iNDF288 determined in situ, but the relationship with uNDF240 was poor.

Enhanced monocyte migration and pro-inflammatory cytokine production by Porphyromonas gingivalis infection.

BACKGROUND AND OBJECTIVE: Porphyromonas gingivalis, a major periodontal pathogen, has been reported to be involved in atherogenesis. In order to further understand this pathogen's link with systemic inflammation and vascular disease, we investigated its influence on murine monocytes and macrophages from three different sources. MATERIAL AND METHODS: Concanavalin A-elicited peritoneal macrophages, peripheral blood monocyte-derived macrophages and WEHI 274.1 monocytes were infected with either P. gingivalis 381 or its non-invasive fimbriae-deficient mutant, DPG3. RESULTS: Infection with P. gingivalis 381 markedly induced monocyte migration and significantly enhanced production of the pro-inflammatory cytokines, tumor necrosis factor-alpha and interleukin-6. Consistent with a role for this pathogen's major fimbriae and/or its invasive capacity, infection with DPG3 had a minimal effect on both monocyte attraction and pro-inflammatory cytokine production. CONCLUSION: Since monocyte recruitment and activation are important steps in the development of vascular inflammation and atherosclerosis, these results suggest that P. gingivalis infection may be involved in these processes.

Infection with a periodontal pathogen induces procoagulant effects in human aortic endothelial cells.

BACKGROUND: Multiple studies have demonstrated a link between periodontal infections and vascular disease. Porphyromonas gingivalis, a major periodontal pathogen, has been shown to adhere to and invade endothelial cells. OBJECTIVE: In order to dissect mechanisms underlying these observations, we assessed the role of P. gingivalis infection in modulating properties of endothelial cells linked to atherothrombosis. METHODS: Primary human aortic endothelial cells (HAEC) were infected with either P. gingivalis 381 or its non-invasive fimbriae-deficient mutant, DPG3. Markers of coagulation and thrombosis were assessed 8 h and 18 h postinfection in cell lysates and supernatants. RESULTS: Infection with P. gingivalis 381 significantly enhanced tissue factor expression and activity, and suppressed levels of tissue factor pathway inhibitor. Furthermore, P. gingivalis infection decreased levels and activity of tissue plasminogen activator, and enhanced plasminogen activator inhibitor-1 antigen and activity. Consistent with an important role for bacterial adhesion/invasion in this setting, infection with DPG3 failed to induce procoagulant properties in HAEC. Most of the above effects of P. gingivalis 381 were more apparent at the later time point (18 h postinfection). This suggests that P. gingivalis infection, rather than having an immediate and direct effect, might activate pathways that, in turn, trigger endothelial procoagulant mechanisms. CONCLUSIONS: Taken together these data demonstrate for the first time that infection with a periodontal pathogen induces procoagulant responses in HAEC.

Membrane instability induced by purified myelin components. Its possible relevance to experimental allergic encephalomyelitis.

The fusogenic properties of purified myelin components in a system employing chicken erythrocytes were studied. Sulphatides, myelin basic protein and the apoprotein of Folch-Lees proteolipid were capable of individually inducing membrane fusion in the presence of Ca2+. By contrast, cerebrosides or a mixture of sulphatides and myelin basic protein (molar ratio 19 : 1) did not show such effect. The fusogenic ability of sulphatide was correlated to its behaviour in mixed monolayers with phospholipids at the air-water interface. Mixed films of sulphatides with phosphatidylcholine or sphingomyelin but not with phosphatidylethanolamine showed reductions of molecular packing and surface potential similar to those found for other fusogenic compounds. The effects of myelin components described could be of importance in the membrane instability and vesicular disruption of myelin occurring in demyelinative disorders.

[Occupational and non-occupational risk factors in bladder cancer patients in an industrialized area located in former East-Germany]. / Berufliche und ausserberufliche Risikofaktoren für das Harnblasenkarzinom in einem ehemaligen Industriegebiet der neuen Bundesländer.

PURPOSE: Several occupational carcinogens are metabolized by polymorphic enzymes. The distribution of the polymorphic enzymes N-acetyltransferase 2 (NAT2; substrates: aromatic amines), glutathione S-transferase M1 (GSTM1; substrates: e. g., reactive metabolites of polycyclic aromatic hydrocarbons), and glutathione S-transferase T1 (GSTT1; substrates: small molecules with 1 - 2 carbon atoms) were investigated. MATERIAL AND METHODS: At the urological department in Lutherstadt Wittenberg, 136 patients with a histologically proven transitional cell cancer of the urinary bladder were investigated for all occupations performed for more than 6 months. Several occupational and non-occupational risk factors were asked. The genotypes of NAT2, GSTM1, and GSTT1 were determined from leucocyte DNA by PCR. RESULTS: Compared to the general population in Middle Europe, the percentage of GSTT1 negative persons (22.1 %) was ordinary; the percentage of slow acetylators (59.6 %) was in the upper normal range, while the percentage of GSTM1 negative persons (58.8 %) was elevated in the entire group. Shifts in the distribution of the genotypes were observed in subgroups who had been exposed to asbestos (6/6 GSTM1 negative, 5/6 slow acetylators), rubber manufacturing (8/10 GSTM1 negative), and chlorinated solvents (9/15 GSTM1 negative). CONCLUSIONS: The overrepresentation of GSTM1 negative bladder cancer patients also in this industrialized area and more pronounced in several occupationally exposed subgroups points to an impact of the GSTM1 negative genotype in bladder carcinogenesis.

Simultaneous analysis of respiratory gases and nitrous oxide in dental patients.

The simultaneous analysis of respiratory gases in the presence of nitrous oxide is described. The modified gas chromatographic technique used is especially applicable to dental situations where continuous monitoring is not necessary. It employs readily available equipment and does not involve interference with other dental procedures.

Intranervous regeneration. The study of motor axon reflexes.

More than 1000 motor axon reflexes (ARs) have been studied. The AR often has a long latency and the first excited branch almost always has the fastest conduction velocity. Sometimes the potentials of the two branches are recorded at the same needle placement, giving the appearance in the EMG tracing of a coupling discharge. Stimulation of the axons in the muscle produces more ARs than stimulation of the nerve trunk. ARs are recorded in denervated muscles but never in normal subjects. All kinds of lower motor neuron lesions produce ARs. They are more frequent in the Charcot-Marie-Tooth syndrome and hereditary neuropathy with liability to pressure palsies where the axonal lesions are mainly located at the traditional sites of entrapment. The possibility of neurolysis in some of these cases has to be considered. Obstetrical brachial plexus palsies furnish many ARs linking two muscles, thus explaining the associated contractions in these cases.

Distribution of cranial and rostral spinal nerves in tadpoles of the frog Discoglossus pictus (Discoglossidae).

We studied the peripheral nervous system of early tadpoles of the frog Discoglossus pictus using whole-mount immunohistochemistry. Double-labeling of muscles and nerves allowed us to determine the innervation of all cranial muscles supplied by the trigeminal, facial, glossopharyngeal, vagal, and hypoglossal nerves. The gross anatomical pattern of visceral, cutaneous, and lateral-line innervation was also assessed. Most muscles of the visceral arches are exclusively supplied by posttrematic rami of the corresponding branchiomeric nerves, the only exceptions being some ventral muscles (intermandibular, interhyoid, and subarcual rectus muscles). In the mandibular arch, the pattern of motor ramules of the trigeminal nerve prefigures in a condensed form the adult pattern, but the muscles of the hyoid arch are innervated by ramules of the facial nerve in a pattern that differs from that of postmetamorphic frogs. With respect to the nerves of the branchial arches, pretrematic visceral rami, typical of other gnathostomes, are absent in D. pictus. Instead, we find a separate series of posttrematic profundal visceral rami. Pharyngeal rami of all branchial nerves contribute to Jacobson's anastomosis. We provide a detailed description of the lateral-line innervation and describe a new ramus of the middle lateral-line nerve (ramus suprabranchialis). We confirm the presence of a first spinal nerve and its contribution to the hypoglossal nerve in D. pictus tadpoles.

Tongue evolution in lungless salamanders, family plethodontidae. III. Patterns of peripheral innervation.

Innervation of the tongue and associated musculature in plethodontid salamanders was studied using Palmgren stained sectioned materials, fresh dissection, and whole mounts of experimental specimens treated with horseradish peroxidase (HRP). Species studied were chosen to represent modes of tongue projection recognized by Lombard and Wake ('77). Special attention was given to species of the genera Plethodon, Batrachoseps, Pseudoeurycea, and Hydromantes, but representatives of other genera were investigated. As expected we found that cranial nerves IX and X and spinal nerve 1 supplied the muscles involved in tongue movement. The peripheral courses of the nerves were traced, and both functionally related and phylogenetically determined routes were found. As relative projection length increases, the nerves supplying the tongue tip also increase in length. When the tongue is at rest the long nerves are stored in coils. The coil of ramus lingualis lies between the ceratobranchials, but that of ramus hypoglossus is more variable, although constant within a species. Ramus hypoglossus bifurcates into separate branches to tongue and anterior musculature of the floor of the mouth. In generalized, presumably primitive, modes the bifurcation and coiling are far anterior. In most of the tongue projection modes bifurcation is relatively posterior, but in one, bifurcation is anterior, but coiling is relatively posterior in position. The most unusual condition is in Hydromantes, in which bifurcation is relatively posterior and a coiled ramus hypoglossus joins a coiled ramus lingualis to form a unique, coiled common ramus to the tongue tip. Hydromantes has the greatest projection distance of any salamander.

Children's drawings about dentistry.

Drawings about the dentist at work were solicited from 1,101 children in grades 2, 4, 6 and 8 in an urban school district. A system to classify the contents of these drawings was developed. The frequency of various items occurring in the children's drawings was determined. The "typical" or most frequent child's drawing of the dentist at work was described. This drawing contained a normal dental chair, dentist, a patient in the chair and dental cabinetry or furniture. The picture was a very matter-of-fact representation. Abnormal or bizarre pictures occurred infrequently. A few children drew pictures that did not relate to dentistry.

Tubular device for intraoral examination of rodents.

The device consists of a tube with a conical end, a base, and a movable stem. The rodent is anaesthetized lightly with ether and inserted quickly into the tube so that the head extends beyond the opening at the conical end, where cheeks, upper and lower incisors are secured to permit illumination and direct visual or microscopic examination of the palate, molars or gingiva.

A case study of a nontraditional basic science curriculum.

This article presents a critical analysis of the ten-year experience of the Department of Oral Biology of the University of Kentucky College of Dentistry with a nontraditional basic science curriculum. The factors that led to the adoption of this curriculum are outlined, and its effects on students, faculty, and the college's administration are described. The pitfalls inherent in this approach and in the individualized self-instructional format for teaching the basic sciences to dental students are discussed. This critical evaluation is aimed at providing information for those contemplating similar sweeping curricular changes in the future to enable them to make rational decisions and to help them predict the effects of such changes on the educational program.

The effects of nitrous oxide administration in the healthy elderly: N2O elimination and alveolar CO2.

Healthy young and elderly males were administered sedative concentrations of nitrous oxide/oxygen (N(2)O/O(2)) under a protocol designed to mimic that used in a dental operatory. Samples of end-tidal expired gas were taken at the end of 30-minutes inhalation of, and periodically for 70 minutes after withdrawal from, nitrous oxide/oxygen. Samples were analyzed to monitor the decline of alveolar nitrous oxide levels and any changes in alveolar carbon dioxide levels, to determine if there were any age-related differences. The fall in alveolar N(2)O following cessation of administration was rapid, and in a double-exponental manner as was expected. No age-related difference in N(2)O decline was observed. Alveolar carbon dioxide (CO(2)) levels were lower and more variable in the elderly group. Both groups exhibited elevated CO(2) levels at the end of the N(2)O period, and an unexplained rise in CO(2) at approximately 30 min post N(2)O.

Monitoring Microvascular Reactivity: (II) - Short-Term Effect of Nitrous-Oxide on the Peripheral Microcirculation in Humans.

A study was carried out to monitor directly the short-term effects of N(2)O/O(2) inhalation-sedation on the peripheral microcirculation in healthy human subjects in a simulated dental setting. The inhalation of 40% N(2)O and 60% O(2) led to a small but significant mean percent decrease (-6.89 +/- 1.2 SEM) in relative vessel diameter in the nailfold capillaries, for the entire N(2)O-breathing period. Individual vessels showed a marked constriction (-31.7% +/- 4.4 SEM, mean maximal decrease); the time to this maximum constriction varied with the individual vessels. This constriction could not be attributed to changes in oxygen or carbon dioxide levels in the alveolar gas, or to changes in heart rate, systolic blood pressure, respiratory rate or temperature. Further studies are indicated to determine whether this effect is sustained with long term administration, and whether it is clinically significant, especially in those patients with acquired cardiac disease or those taking vasoactive drugs.

Monitoring microvascular reactivity in dental subjects.

In this section of a larger study, a system for monitoring changes in the microcirculation, in humans in the dental setting, is described. The technique involves clinical nailfold capillary photomicroscopy and electronic image-scan measurements. The system was tested using reactive hyperemia after vascular occlusion; it proved reliable and sufficiently sensitive for measuring vascular reactivity in humans. (In a subsequent paper, clinical findings relative to the use of this technique with patients undergoing nitrous oxide/oxygen anesthesia will be presented).The importance of the microcirculation for the integrity of the tissues cannot be overemphasized. Since the term "microcirculation" can be defined as the microscopic subdivisions of the vascular system that lie within the tissue proper and are exposed to its immediate environment,(1) it is evident that most of the exchange of nutrients and waste products occuring in the tissue will occur at this level. Furthermore, the adequacy of tissue perfusion during drug administration, or during and after anesthesia, is dependent on the adequacy and reactivity of this subdivision of the vascular system.(2)A basic prerequisite to the understanding of microcirculatory function in a given vascular bed is the precise quantitation of dimensional changes in those vessels(3). Dynamic measurements in vivo are required, since it is difficult, if not impossible, to ensure that the dimensions obtained from fixed tissue specimens are accurate measures of those occurring in the living state. This is especially true where vessel dimensions are rapidly changing in response to endogenous or exogenous influences. Unfortunately the task of in vivo measurement of microvascular dimensions is difficult in most microcirculatory beds. Since the vessels are an integral part of a threedimensional structure,(4) the tasks of visualizing, isolating and measuring the vessels are formidable. These difficulties are compounded if the particular vessels to be studied are in human subjects where surgical intervention is unacceptable. For these reasons, previous studies of dimensional changes in the microcirculation, involving a variety of techniques (still photography, cinematography, television microscopy,(5) image-scanning,(6) image-shearing(7,8) and optical density measurements(9)), were almost always carried out in animals.In order to determine the effects of drugs and anesthetic gases on the peripheral microcirculation in human subjects undergoing dental treatment, we have employed a non-invasive photomicrographic method to measure planar dimensional changes in human nailfold capillaries. In this report we will describe this technique, its use in measuring microcirculatory changes in humans in a dental setting, and the results of a study undertaken to determine if it is sensitive enough to measure an induced change in vascular dimensions.

The effect of nitrous oxide and age on psychological and psychomotor performance.

Healthy older and younger males were compared on several psychomotor and cognitive measures before, during, and after N(2)O inhalation. Age did not appear to be a significant factor in determining response to N(2)O though on several measures younger subjects are superior to older under all conditions. N(2)O had a significant effect only on reaction time and facial recognition tasks. The relation of these findings to previous work is discussed.

Effect of age on the digit blood flow response to sedative concentrations of nitrous oxide.

Twenty healthy male subjects [11 young, x̄ = 25.4 ± 0.8 (SEM) years old; 9 elderly, x̄ = 64.5 ± 0.7 years] volunteered for a study designed to investigate the effect of age on several cardiovascular parameters to inhaled N(2)O-O(2). The protocol was designed to mimic the administration of N(2)O-O(2) for sedation in the dental office, although no dental treatment was performed. Clinical criteria were used to judge the appropriate sedative level for each subject; no attempt was made to establish doseresponse relationships. Digit blood flow was measured by strain-gauge plethysmography, and heart rate, arterial blood pressure, respiratory rate, and skin temperature were monitored and recorded. N(2)O and CO(2) levels were monitored in end-tidal gas samples by gas chromatography; machine gauge readings were calibrated against known gas mixtures by the same technique.Under the conditions of this experiment both healthy young and healthy elderly subjects experienced a marked (200-300%) increase in digit blood flow during N(2)O inhalation, compared to that during air and 100% O(2) inhalation. There was no significant difference in the degree of flow increase between young and elderly subjects. Also, there were no significant differences in the response of these healthy young and healthy elderly subjects to sedative concentrations of N(2)O with regard to heart rate, arterial blood pressure, respiratory rate, skin temperature, or mean end-tidal CO(2) levels. The data indicate that N(2)O, in the concentrations routinely administered in the dental office for sedation, does not have a differential effect on the measured parameters in healthy elderly and healthy young males.