Treatment of osteoporosis with human parathyroid peptide and observations on effect of sodium fluoride.

OBJECTIVE--To evaluate the need for a randomised study of treatment of spinal osteoporosis with human parathyroid peptide in the secondary prevention of crush fractures; to study the effect of human parathyroid hormone peptide 1-34 plus sex hormones on vertebral body cancellous bone; and, separately, to determine the effect of relatively low doses of sodium fluoride plus calcium on spinal bone mineral density. DESIGN--Open study of patients with primary or postmenopausal osteoporosis. All patients had serial bone densitometry of the spine by quantitative computed tomography and dual photon absorptiometry as well as serial densitometry of the radial midshaft (cortical) and radial distal (trabecular) bone by quantitative computed tomography. Changes in the spinal bone not forming the spongiosa of the vertebral bodies ("cortical" bone) were determined from the difference between the two axial measurements, after correction to the same units of measurement. SETTING--Northwick Park Hospital and Medical Research Council Clinical Research Centre. PATIENTS--24 Patients who fulfilled the conventional criteria for type 1 (vertebral) osteoporosis not secondary to recognised causes other than sex hormone deficiency and with at least one crush or wedge vertebral fracture and a spinal bone density (quantitative computed tomography) less than 80 mg/cm3 or two or more fractures. Twelve patients received human parathyroid peptide and 12 sodium fluoride; they were not randomised. MAIN OUTCOME MEASURES--Trends in axial and peripheral bone mass values determined by linear, time dependent regression analyses. RESULTS--The patients receiving the peptide showed a substantial increase in vertebral spongiosa (mean 25.6 mg/cm2 two years after the start of treatment). No significant changes were seen in spinal cortical or radial bone density. The patients receiving sodium fluoride showed roughly equal increases in cancellous and cortical bone over the same period (mean increase in vertebral spongiosa 16.1 mg/cm3). No significant changes were seen in radial bone. CONCLUSIONS--Treatment of postmenopausal women with human parathyroid peptide selectively increases spinal cancellous bone density by amounts that may prove useful in secondary prevention. Peptide treatment should now be tested in a randomised study in which the important end point is prevention of fractures as the usefulness of sodium fluoride in this context is doubtful.     

The effect of hydrogen fluoride on two pigments in coleus

Coleus blumei Benth. cv. ‘12th Man’ was fumigated with hydrogen fluoride gas. The treatment caused the development of lesions which originally involved the mesophyll but spread to and eventually included the epidermis. An anthocyanin, cyanidin-3,5-diglucoside acylated with p-coumaric acid, was destroyed and it was postulated that the flavanonol, dihydrokaempferol, was converted to the flavone, apigenin. The anthocyanin destruction and pigment conversion occurred following membrane injury and mixing of the cellular constituents.     

The effect of ionic strength on the kinetics of fluoride binding to cytochrome c peroxidase.

The kinetics of the reaction between cytochrome c peroxidase and fluoride was investigated as a function of ionic strength over the pH range 4 to 8. The ionic strength was varied between 0.01 and 0.10 m. At 0.01 m ionic strength, the reaction rates were determined between pH 2.7 and 9.2. A consideration of the ionic strength and pH dependence of the association rate constant for the fluoride-cytochrome c peroxidase reaction leads to the conclusion that hydrofluoric acid is the only significant reactive form of the ligand between pH 2.5 and 8. Above pH 8, binding of fluoride anion contributes to the apparent association rate even though the pH-independent rate constant for fluoride anion binding is more than 3 × 10⁵ times smaller than the rate constant for hydrofluoric acid binding.     

The effect of diet calcium on fluoride toxicity in growing rats

The effect of dietary Ca in response to fluoride (F) treatment was investigated in rats. Rats were maintained on either adequate (0.5%) or high (2.0%) dietary Ca and given for 5 weeks, NaF in drinking water. The minimum NaF levels that inhibited body growth and reduced survival were 300 mg/L with 0.5% diet Ca and 550 mg/L with 2.0% diet Ca. With these toxic F doses, bone histology showed increased formation surfaces and thickened osteoid seams (osteoid index 6-7%). Fluoride doses 30% below toxic levels (200 and 350 mg/L for 0.5 and 2.0% diet Ca, respectively) had no demonstrable effect on bone. Additional diet Ca reduced F absorption from 76 +/- 3 to 47 +/- 3% for 0.5 and 2.0% diet Ca, respectively. Comparable absorbed doses of F produced comparable effects on bone and body growth but, with additional dietary Ca, these effects were observed with 50% lower serum and bone F levels. Variable response to NaF therapy can be produced in rats by alterations in dietary Ca alone. Results indicate that for clinical treatment the NaF dose needs to be adjusted on an individual basis but neither serum nor bone F levels can be used reliably to establish optimal doses.     

氟化氢熏气对植物影响的防护研究

研究采用开顶式熏气装置,用不同浓度的ＣａＣｌ２、Ｃａ（ＯＨ）２、Ｖｃ和Ｃ６Ｈ６ＣＯＯＮａ（苯甲酸钠）作为小麦的氟污染防护剂。通过实验研究了其防护效果并作了进一步的机理。实验结果表明,０．５‰Ｃａ（ＯＨ）２防护效果极显著,０．１‰Ｃａ（ＯＨ）２、１‰Ｖｃ和１‰ＣａＣｌ２也有显著的防护作用,因此,使用防护剂时掌握其浓度是至关重要的。     

Influence of dietary fluoride restriction on regulation of plasma nd soft tissue fluoride contents.

The adjustments in total fluoride concentration in plasma, bones, liver, and muscle were examined when rats were given a diet of very low fluoride content following a dietary regimen of elevated fluoride intake. The animals received a diet containing 34 ppm of fluoride and water with 50 ppm added fluoride in the 28-day initial period and in the depletion period they were given a diet containing only 0.21 ppm of fluoride and distilled water. The findings indicated a 12-fold increase in the fluoride content of the humeri after 28 days of high-flurodie intake with a greater increment by the epiphyses than by the diaphyses. During 21 days of the depletion period the skeletal fluoride was reduced by only 7.7% indicating a marked retention of fluoride during processes of bone remodeling and growth. The plasma, muscle, and liver total fluoride contents were significantly increased at the end of the period of high-fluoride intake, but these concentrations were found to be restored to base-line levels in 3-7 days of the depletion period. By comparison of the distribution of total fluoride with injected radiofluoride between tissue and plasma waters, it was concluded that muscle and liver contain bound fluoride that does not exchange completely with ionic fluoride.     

The effect of fluoride on the state of aggregation of adenylate cyclase in rat liver plasma membranes.

Irradiation inactivation was used to monitor changes in the state of adenylate cyclase in rat liver plasma membranes in the presence of F-.F- caused a decrease in the target size from 328000 to 237000 at 0 degrees C and from 329000 to 219000 at 30 degrees C. Adenylate cyclase was activated by F- at both 0 degrees C and 30 degrees C. The effect of F- was biphasic, activating up to a concentration of 10mM and inhibiting at higher concentrations. If adenylate cyclase weas maximally activated with glucagon and p[NH]ppG ([beta gamma-imido]GTP) all concentrations of F- were inhibitory. The implications of the results with respect to the mechanism of activation of adenylate cyclase are discussed.     

The effect of sodium fluoride on cereal seed germination and seedling growth

Abstract. Fluoride has been shown to inhibit germination and seedling establishment in barley cv. Natasha, wheat cv. Axona and rice cv. Ishikari. The concentrations of fluoride were selected so as to give a satisfactory dose-response relationship and also to relate to levels of fluoride present under natural conditions. Concentrations used were zero, 0.5, 1.0, 10 and 40 mol m⁻³ sodium fluoride. In germination studies, barley was found to be least tolerant and rice most tolerant of fluoride. The inhibition was found to be a response to fluoride itself and the observed effects were not due to pH, sodium or an unspecific effect of halide ion. Phosphate, applied at two concentration levels, was unable to overcome the inhibition. Fluoride was also shown to inhibit seedling growth. The inhibitory effects of fluoride may be accounted for by a wide range of metabolic effects including inhibition of gibberellic acid–triggered alpha amylase activity during germination, and later on to inhibition of chlorophyll synthesis in the developing leaves.     

氟对正畸儿童牙面菌斑变形链球菌的影响

目的:观察和探讨2%氟化钠对正畸患者牙面菌斑内细菌总数及变形链球菌数的影响.方法:选择34例正畸儿童,分为两组,试验组涂布2%氟化钠;对照组不做处理.分别于戴用矫治器前,戴入后1月采集上颌牙唇颊面菌斑,测定菌斑中细菌总数及变形链球菌数.结果:对照组戴用后1月,细菌总数及变形链球菌数较戴用前明显增加(P＜0.01).对照组与试验组戴用后1月相比,试验组细菌总数及变形链球菌数明显少于对照组(P＜0.05).结论:戴用固定矫治器后,牙面菌斑内细菌总数及变形链球菌数较戴用前增加,应用2%氟化钠可明显抑制正畸患者口腔内变形链球菌数,减少龋坏发生.