Prevention of osteoporosis and pathological calcifications

Based on physiological data about the influence of magnesium compounds on the degree of saturation of blood plasma with calcium phosphates, we have hypothesized in 1988 that magnesium deficiency is the real cause of osteoporosis and pathological calcifications. The incidence of these diseases is among the elderly as high as 40%. These diseases are the reason that there is such a discrepancy between the morbidity and mortality curve for the elderly as a function of age. Meanwhile it has been proven that a. in all osteoporotic patients the intracellular magnesium content of the erythrocytes is lower than in controls, b. this content can be restored to normal by oral magnesium supplementation without increasing the serum magnesium level, c. by this supplementation the bone density in perimenopausal women increases and d. this supplementation keeps the blood plasma and probably also the other extracellular fluids undersaturated with octocalcium phosphate so that it is impossible for pathological calcifications to occur or to progress. The possible benefits for dentistry are the following: a. perhaps mandibular resorption is retarded or inhibited by oral magnesium supplementation and b. this treatment may also help to inhibit or diminish dental calculus formation in heavy calculus formers. Since both aspects are accessible to experimental clinical investigation, we will soon have the answer to these questions.     

The mineral solubility of human tooth roots

Whole roots of molars that had never been exposed to the mouth were exposed to calcium and phosphate-containing buffer solutions with discrete values of pIOHA [i.e. -log(a10Ca2+ X a6PO4(3-) X a2OH-)] at various pH. From densitometric measurements on contact-microradiographs of transverse sections of the roots the rate of demineralization (Vdem) was calculated. Vdem changed non-linearly as a function of pIOHA and became zero at a pIOHA-value of 105.3 +/- 0.4; this is substantially lower than the corresponding value of 118 +/- 1 for enamel. Thus root mineral is more soluble than enamel mineral. The critical pH for root caries appears to be about 6.7, provided that the plaque fluid follows about the same pH-pIOHA- pathway as acidified saliva.     

Age at onset, childhood psychopathology, and 2-year outcome in psychotic bipolar disorder

OBJECTIVE: The relationships of age at onset and childhood psychopathology to 2-year clinical and functional outcomes in first-admission patients with bipolar I disorder were examined. METHOD: Patients with bipolar I disorder (N=123) presenting with psychotic symptoms were followed over a 2-year period. Age at onset was stratified into <19 and >or=19 years. Childhood psychopathology was categorized as behavior problems, other psychopathology, and none. Functional and clinical outcomes were rated with standard measures. RESULTS: Childhood psychopathology and age at onset were independently related to poorer functional and clinical outcome. In the multivariate models that included psychopathology, age at onset, sex, and education, early age at onset was related to incomplete remission, and childhood psychopathology was related to functional outcome. CONCLUSIONS: Childhood psychopathology and age at onset contribute independently to outcomes of bipolar disorder. Childhood psychopathology is a much stronger predictor of functioning than age at onset.     

Lattice parameters and cation distribution of solid solutions of calcium and strontium hydroxyapatite.

Solid solutions of strontium and calcium hydroxyapatite were synthesized by solid-state reaction. Lattice parameters of these compounds were determined using two types of Guinier cameras. They vary linearly with the molar percentage of strontium hydroxyapatite. The distribution of Ca and Sr ions over the fourfold and sixfold positions in the apatite structure was determined by comparing experimental and calculated values for the intensity ratios of suitable reflections. A slight, although significant, preference of Sr for the sixfold position was found. An ideal behavior is predicted for these solid solutions.     

Zinc deficiency-induced changes in the lipid composition and ultrastructure of rat incisor teeth

The lipids and ultrastructure of the forming, maturing and erupted parts of incisors were compared in rats fed a zinc-deficient diet for 28 days, pair-fed rats and control rats. The lipid levels in the forming portions of zinc-deficient incisors were 30-50% below control levels and were associated with longer Tomes' processes in the secretory ameloblasts, porosities in the forming enamel and fewer malachite green-aldehyde-phospholipid aggregates in the predentine. No marked structural changes were seen in the erupted portions of the teeth, although variations in lipid composition were detected both in the maturing and erupted parts. No differences were found between teeth from the 3 groups of animals for Na, Mg, Cl, Ca and P signals with the electron microprobe.     

What is reflex sympathetic dystrophy?

In the literature there is no unanimity with respect to the diagnosis of reflex sympathetic dystrophy (RSD). Frequently, the diagnosis is established on mere clinical grounds. In our opinion, however, bone scintigraphy is of major importance for the diagnosis. Using this examination, true RSD can be clearly differentiated from other conditions which are incorrectly diagnosed and treated as RSD. If the bone scan is not suggestive of RSD, the clinical picture, radiological examination and vascular scan may lead to the correct diagnosis. This may be a pseudodystrophy, in which a hypovascularization is found right from the start, while in true RSD there is initially a hypervascularization. Other conditions which may be confused with RSD are causalgia, neurotic compulsive postures, hysterical conversion, malingering and even self-mutilation. In the spontaneous course of RSD three phases can be distinguished. Stage I is the warm or hypertrophic phase, stage II the cold or atrophic phase. Per definition the third phase corresponds to stabilization or, in rare instances, to healing. By means of the vascular scan the correct stage can be determined, and the results of treatment evaluated. Finally it should be noted that in children the condition is completely different from true RSD, as it concerns a pseudodystrophy or disuse-related dystrophy. This condition may also be seen in adults and adolescents, usually females. The bone scan is always negative. In this way bone scintigraphy constitutes the means to answer the question as to what RSD is and what it is not. An algorithm for the differential diagnosis is presented.     

Roles of hydrogen peroxide in thyroid physiology and disease

CONTEXT: The long-lived thyroid cell generates, for the synthesis of thyroid hormones, important amounts of H2O2 that are toxic in other cell types. This review analyzes the protection mechanisms of the cell and the pathological consequences of disorders of this system. EVIDENCE ACQUISITION: The literature on H2O2 generation and disposal, thyroid hormone synthesis, and their control in the human thyroid is analyzed. EVIDENCE SYNTHESIS: In humans, H2O2 production by dual-oxidases and consequently thyroid hormone synthesis by thyroperoxidase are controlled by the phospholipase C-Ca2+-diacylglycerol arm of TSH receptor action. H2O2 in various cell types, and presumably in thyroid cells, is a signal, a mitogen, a mutagen, a carcinogen, and a killer. The various protection mechanisms of the thyroid cell against H2O2 are analyzed. They include the separation of the generating enzymes (dual-oxidases), their coupling to thyroperoxidase in a proposed complex, the thyroxisome, and H2O2 degradation systems. CONCLUSIONS: It is proposed that various pathologies can be explained, at least in part, by overproduction and lack of degradation of H2O2 (tumorigenesis, myxedematous cretinism, and thyroiditis) and by failure of the H2O2 generation or its positive control system (congenital hypothyroidism).