Radiographic quantification of alveolar bone level changes

The "random burst" theory has recently been proposed as an explanation of the pattern of periodontal disease progression. The theory predicts that the progression of bone loss at individual sites is not dependent upon previous bone loss and age. A longitudinal radiographic study was designed to test this hypothesis, and to describe the changes in bone level over 2 years in a group of 180 subjects (18-68 years of age) who were not under systematic periodontal treatment. The results indicated that 94% of the sites did not show significant changes in the alveolar bone level during the observation period. The mean annual bone loss for the total population was 0.11 mm. By regressing longitudinal bone loss upon age, it was shown that the rate of bone loss increased rapidly between 33 and 56 years of age while a different pattern was shown for the age intervals 18-32 and 57-68 years. Also, the rate of bone loss increased with increasing initial bone loss. This was less evident in the oldest age group. It was concluded that the progression of bone loss in the present material is consistent with a "burst" theory. However, the progression did not occur randomly with regard to previous loss of alveolar bone and time.     

Effects of sodium and GTP on the binding kinetics of [3H]diprenorphine in NG 108-15 cell membranes

Summary Equilibrium binding isotherms of [³H]diprenorphine in membranes from NG 108-15 cells are consistent with a homogenous population of binding sites. Upon addition of Na⁺, Mg²⁺ and GTP, only a 2-fold reduction in affinity with a minor decrease in the number of sites is observed. Dissociation curves of [³H]diprenorphine, however, are clearly biphasic: in the absence of Na⁺, Mg²⁺ and GTP, 80% of the bound ligand dissociates slowly with at _1/2 of 100 min, and only 20% rapidly (t _1/2 4.5 min). In the presence of Mg²⁺, nearly all the binding is found in the slowly dissociating form. Upon the addition of either Na⁺ or GTP, 20–30% of the binding dissociates more rapidly. The rate constant of the rapidly dissociating form generated by Na⁺, however, is 2.5 times greater than that induced by the presence of GTP. Thus, the addition of both, Na⁺ and GTP, converts about 80% of the receptor into a very fast dissociating form (t _1/2 1.7 min).Exposure of intact cells to pertussis toxin (10 ng/ml) or treatment of membranes with N-ethyl maleimide (500 M), strongly reduces the proportion of the slowly dissociating component. Following these treatments, the effect of GTP is reduced or abolished, but that of Na⁺ remains unaffected.We conclude from these data that the effects of Na⁺ and GTP are not only distinct in site but also in mechanism of action and that there are three forms of opioid receptors that can be differentiated by their kinetic properties. The slowly dissociating receptor form requires a functional N unit.     

Dopamine in the conscious dog with chronic heart-block

Summary The chronotropic effects of dopamine were studied in the conscious dog with chronic A-V block. Dopamine at 12.5–200 g/kg and 12.5–50 g/kg/min lowered atrial rate independently of dose. After blockade of muscarine receptors or alpha-adrenoceptors, it raised atrial rate. After blockade of dopamine receptors, dopamine still lowered atrial rate, and did so dose-relatedly after blockade of beta-adrenoceptors. It raised ventricular rate, and at high doses also induced ventricular rhythm disorders. Blockade of muscarine receptors enhanced the ventricular cardioaccelerator effect of dopamine (P<0.025) at 100 g/kg, while blockade of alpha-adrenoceptors reduced it (P<0.05). Blockade of dopamine receptors did not modify this effect, but blockade of beta-adrenoceptors reversed it. Dopamine at 25–200 g/kg raised mean blood pressure. This effect was enhanced by blockade of muscarine receptors, reversed by blockade of alpha-adrenoceptors, and was unaffected by blockade of beta-adrenoceptors or dopamine receptors. These results show that the atrial cardiomoderator effect of dopamine is a vagal reflex response to its hypertensive action, and that it is limited by its direct beta-adrenergic stimulating action. They also show that the ventricular cardioaccelerator effect of dopamine is attenuated by a reflex vagal depressor effect consequent to the induced hypertension. No evidence was found for the existence of positive chronotropic dopamine receptors in either atria or ventricles.A preliminary report of these findings was presented at the Symposium on Peripheral Dopaminergic Receptors, July 1978, in Strasbourg, France (Boucher et al. 1979b)     

The influence of bile salts on the absorption in vitro and in vivo of propranolol

The lipophilicity of propranolol is increased by some bile salts which form ion-pairs. In the presence of taurodeoxycholate, the logarithm of the apparent partition coefficient (log P) of propranolol is increased. Moreover, the apparent diffusion constants in vitro of propranolol as ion-pairs at pH 3.0–6.0 are about 5–6 times higher than those of propranolol alone.

The area under the curve values of plasma concentration—time profiles of propranolol, following its oral administration to rabbits together with taurodeoxycholate, are about 1.4 times higher than those after administration of propranolol alone. Moreover, after the admistration of propranolol with taurodeoxycholate the plasma concentration rises more rapidly, with a point of inflection between 0.5 and 1.5 h, than after administration of propranolol alone.

Taurodeoxycholate does not modify the first-pass effect of propranolol in rabbits following intravenous and intraportal administration. The absorption of an oral dose of propranolol in the presence of taurodeoxycholate increases from 70% to 100%, due to the higher lipophilicity of the ion-pair. The plasma concentration—time curves suggest the hypothesis that greater absorption of the ion-pair occurs mainly in the upper region of the gastrointestinal tract.     

Dissolution test for felodipine tablets using chemical oxidation in situ to maintain 'sink conditions'

A test model is described for the determination of the dissolution rate of the vasodilator, felodipine, a derivative of dihydropyridine that is practically insoluble in water. ‘Sink conditions’ are maintained by means of an oxidizing agent, ceric sulphate, which reacts rapidly with dissolved drug molecules in the dissolution fluid. A pyridine derivative is formed quantitatively in the oxidation reaction. The amount of dissolved felodipine is calculated from the concentration of the pyridine derivative, as determined by reversed-phase liquid chromatography. Dissolution rates depend on the concentration of the oxidizing agent so that high concentrations accelerate dissolution. The dissolution test suggested for 25-mg felodipine tablets is performed in 500 ml fluid that contains 5 mM ceric sulphate in 0.12 M sulphuric acid. The test is performed on single tablets with USP paddle equipment. Dissolution rates for nine different tablet compositions are correlated to such bioavailability parameters as maximum plasma concentration and total area under the plasma concentration—time curve. Interferences and limitations of the method are discussed.     

The Effect of Continuous Intake of Lactobacillus gasseri OLL2716 on Mild to Moderate Delayed Gastric Emptying: A Randomized Controlled Study

Probiotics have been suggested to be effective for functional dyspepsia, but their effect on gastric motility is not clear. We evaluated the effect of Lactobacillus gasseri OLL2716 (LG21 strain) on mild to moderate delayed gastric emptying by a double-blind, parallel-group, placebo-controlled, randomized trial. Participants (n = 28) were randomly assigned to ingest LG21 strain-containing yogurt (LG21 strain group) or LG21 strain-free yogurt (placebo group) for 12 weeks. The ¹³C gastric emptying breath test was performed to measure the gastric emptying rate over time following ingestion of a liquid meal, and the time to reach the peak (Tmax) was used as an indicator of gastric emptying. We also measured the salivary amylase concentration, an indicator of autonomic dysfunction under stress. The per-protocol population (n = 27, male n = 4, female n = 23) was evaluated for efficacy. When a ≥30% reduction in the difference between participant’s Tmax and the Japanese mean Tmax was defined as an improvement, the odds ratio of improvement in delayed gastric emptying compared to placebo after 12 weeks was 4.1 (95% confidence interval, 0.8 to 20.2). Moreover, salivary amylase concentrations were significantly lower than in the placebo group, indicating an improvement in autonomic function. The present data were not enough to support the beneficial effects of the LG21 strain on delayed gastric emptying. However, if we define the odds ratio in further study investigated with a larger number of participants, LG21 strain might be expected to have some impact on delayed gastric emptying.     

Is There Association between Altered Adrenergic System Activity and Microvascular Endothelial Dysfunction Induced by a 7-Day High Salt Intake in Young Healthy Individuals

This study aimed to test the effect of a 7-day high-salt (HS) diet on autonomic nervous system (ANS) activity in young healthy individuals and modulation of ANS on microvascular endothelial function impairment. 47 young healthy individuals took 7-day low-salt (LS) diet (3.5 g salt/day) followed by 7-day high-salt (HS) diet (~14.7 g salt/day). ANS activity was assessed by 24-h urine catecholamine excretion and 5-min heart rate variability (HRV). Skin post-occlusive reactive hyperemia (PORH) and acetylcholine-induced dilation (AChID) were assessed by laser Doppler flowmetry (LDF). Separately, mental stress test (MST) at LS and HS condition was conducted, followed by immediate measurement of plasma metanephrines’ level, 5-min HRV and LDF microvascular reactivity. Noradrenaline, metanephrine and normetanephrine level, low-frequency (LF) HRV and PORH and AChID significantly decreased following HS compared to LS. MST at HS condition tended to increase HRV LF/HF ratio. Spectral analysis of PORH signal, and AChID measurement showed that MST did not significantly affect impaired endothelium-dependent vasodilation due to HS loading. In this case, 7-day HS diet suppressed sympathetic nervous system (SNS) activity, and attenuated microvascular reactivity in salt-resistant normotensive individuals. Suppression of SNS during HS loading represents a physiological response, rather than direct pathophysiological mechanism by which HS diet affects microvascular endothelial function in young healthy individuals.     

2005—2015年全国肝癌发病趋势分析

目的 通过分析《中国肿瘤登记年报》中肝癌发病的变化趋势,为有效开展肝癌防治工作提供科学参考依据。 方法 整理2005—2015年肝癌发病数据,运用Joinpoint软件进行回归模型分析我国肝癌发病率变化趋势,利用R软件进行负二项回归模型分析肝癌在人群水平上发病的危险因素。 结果 2005—2015年我国肝癌标化发病率基本表现为农村高于城市,男性高于女性。肝癌标化发病率总体呈下降趋势(AAPC=-0.818,P<0.05);城乡男性肝癌年龄别发病率大多在30~岁年龄组呈快速上升趋势,农村和城市女性年龄别发病率分别在45~和50~岁年龄组,随时间增长呈快速上升趋势。城市人群的发病风险是农村人群的1.198倍(95%CI:1.041~1.379,P＜0.05),男性是女性的3.715倍(95%CI:3.228~4.275,P＜0.001),每增加5岁,肝癌的发病风险平均增大8.0%(OR=1.080,95%CI:1.077~1.083,P＜0.001)。 结论 2005—2015年我国肝癌发病情况总体呈下降趋势,但存在城乡、性别及年龄差异,需要制定更加有效完善的预防措施,从而达到预防肝癌的最优效果。     

High Case-Fatality Rate for Human Anthrax,Northern Ghana, 2005–2016

The human cutaneous anthrax case-fatality rate is ≈1% when treated, 5%–20% when untreated. We report high case-fatality rates (median 35.0%; 95% CI 21.1%–66.7%) during 2005–2016 linked to livestock handling in northern Ghana, where veterinary resources are limited. Livestock vaccination and access to human treatment should be evaluated.     

玉米浆用量、渗透压和耗糖速率对甘油发酵的影响

Candida krusei发酵生产甘油过程中,菌体生长由玉米浆限制,菌体对玉米浆的得率为1．63g/g,培养其中玉米浆浓度相同时,增加渗透压或通过流加补料限制生长阶段的菌体生长,可使甘油生产阶段的比耗糖速率减慢,比耗糖速率保持在不很高的水平,可以因消耗的葡萄糖用于生长,维持,甘油和副产物形成所占比例的变化而提高甘油得率。