羟基磷灰石骨水泥中碳酸根存在的意义及其与组织的相容性

目的:观察碳酸化羟基磷灰石骨水泥与磷酸钙骨水泥的组织学反应差异,判定羟基磷灰石骨水泥中碳酸根存在的意义及其对组织相容性的影响。方法:实验于2000-01/2002-08在解放军总医院骨科研究所及医学动物实验中心完成。①碳酸化羟基磷灰石骨水泥的制备:以碳酸钙、磷酸三钙、磷酸氢钙等化学试剂为原材料,合成碳酸化羟基磷灰石骨水泥粉体。以磷酸氢二钠和磷酸二氢钠合成0.2mol/L磷酸钠缓冲液,作为固化液。固相/液相=1g/0.4mL。②细胞毒性实验:以磷酸钙骨水泥为对照,观察碳酸化羟基磷灰石骨水泥与骨髓基质细胞共培养后细胞的形态以及与材料表面的黏附性,并分别于2,4,6,8d用MTT法测量细胞的相对增殖率。③肌内埋植实验:选用成年新西兰兔8只,按随机数字表法分为实验组和对照组,每组4只。实验组将碳酸化羟基磷灰石预制成形,植入家兔背部肌肉组织内。对照组动物植入磷酸钙骨水泥。术后2,4,8,12周每组分别麻醉处死1只,观察材料周围组织的炎性反应和纤维包膜的形成情况。结果:纳入动物8只,均进入结果分析。①碳酸化羟基磷灰石骨水泥和磷酸钙骨水泥的浸提液分别与兔骨髓基质细胞共培养后,细胞的形态、与材料表面的黏附性以及细胞相对增殖率等无显著差别。②两种材料植入家兔背部肌肉内,材料周围形成的纤维组织包膜厚度均低于30μm,均未发现炎性细胞反应。植入12周时实验组碳酸化羟基磷灰石骨水泥的平均包膜厚度略低于对照组磷酸钙骨水泥(分别为22.7,26.1μm)。结论:碳酸化羟基磷灰石骨水泥和磷酸钙骨水泥均具有优秀的组织相容性,碳酸根的存在可以减少羟基磷灰石骨水泥的组织反应。     

Calcium antagonists and thiazide diuretics have opposite effects on blood rheology and radial artery compliance in arterial hypertension: A randomized double-blind study

Summary— In addition to their effects on blood pressure, antihypertensive agents may produce additional effects on blood rheology and arterial compliance abnormalities which may play a role in target-organ damage. However, these effects may depend only on the specific pharmacological properties of certain antihypertensive agents, and may be partly unrelated to blood pressure lowering action. We compared the effects of nitrendipine 20 mg once daily to hydrochlorothiazide 25 mg once daily in 33 mildly to moderately hypertensive and otherwise healthy patients, in a double blind parallel group trial. Blood rheology (blood fibrinogen and protein concentrations, hematocrit, plasma viscosity and whole blood viscosity at shear rates 0.2 to 128 s⁻¹, erythrocyte deformability and aggregation) and radial artery diameter and compliance (Nius I + Finapres) were measured at baseline and after 2 months of treatment. Both drugs produced similar blood pressure lowering. Blood viscosity increased for all shear rates in the hydrochlorothiazide group and decreased in the nitrendipine treated group. Erythrocyte deformability increased in the nitrendipine but not in the thiazide group. Radial artery diameter and compliance were not different between the two groups but there was a trend towards an increase in cross-sectional compliance in the hydrochlorothiazide group and towards a decrease in the nitrendipine group. Our data show that, in mildly hypertensive patients, blood pressure control by nitrendipine produced more favourable effects on relevant rheological variables than hydrochlorothiazide. Radial artery compliance changes tended to be altered also in opposite directions by the two agents. The significance and the clinical relevance of these effects may require further investigations.     

Abnormalities of the skeletal muscle in hypertrophic cardiomyopathy. Spectroscopy using phosphorus-31 nuclear magnetic resonance

There have been several reports of electromyographic and histological changes of striated skeletal muscle, especially of the type I oxidative fibres, in hypertrophic cardiomyopathy. In order to determine whether these anomalies also cause metabolic changes, a P-31 magnetic resonance spectroscopic study was undertaken at rest and on exercise in 5 pauci-symptomatic patients and 10 control subjects. The 5 patients had primary hypertrophic cardiomyopathy without alteration of systolic function or signs of congestive cardiac failure (Stages I or II). There were no clinical signs of myopathy. None of the patients were receiving betablocker therapy at the time of investigation. No significant difference was observed at rest. Intracellular acidosis was particularly pronounced in 2 of the 5 patients at the peak of exercise. In addition, the phosphocreatine recovery time (T1/2) was longer in the patient group (3.4 +/- 1.7 vs 1.6 +/- 0.9 mn; p less than 0.01) suggesting a mitochondrial metabolic oxidation abnormality. These results suggest that some patients with primary hypertrophic cardiomyopathy have abnormalities of mitochondrial oxidation in their striated skeletal muscle which can be demonstrated by P-31 magnetic resonance spectroscopy. This would suggest a global abnormality of striated muscle which, at a more advanced stage of the disease, could account for decreased effort tolerance in these patients.     

Inducible production of human macrophage growth factor, CSF-1

A panel of human cell lines was screened for production of colony- stimulating factor-1 (CSF-1) using a specific radioreceptor assay and criterion of macrophage colony growth in mouse bone marrow culture. The pancreatic carcinoma lines MIA PaCa and PANC were found to secrete high levels of CSF-1. In a bone marrow proliferation assay, the activities from these two lines were blocked by a CSF-1 specific neutralizing antiserum, confirming the predominant content of this macrophage growth factor. MIA PaCA cells stopped secreting CSF-1 when transferred to various serum-free media. Serum-free production could be reinitiated by phorbol myristic acetate (PMA). Purified CSF-1 from serum-free MIA PaCa cells stimulated the formation of 14-day colonies from total and nonadherent mononuclear human bone marrow cells. Most of the colonies consisted exclusively of large, dispersed macrophages that were intensely stained for nonspecific esterase. Although similar numbers of human 14-day colonies were stimulated by CSF-1 and other CSFs, more CSF- 1 was required for the proliferation of human as compared with murine bone marrow progenitors. Northern analysis of mRNA from induced-MIA PaCa cells, using a human CSF-1 oligonucleotide probe, revealed multiple species of CSF-1 mRNA ranging from 1.5 to 4.5 kilobases (kb). Uninduced, serum-free cultures showed only the largest mRNA species, suggesting that serum removal interfered with CSF-1 mRNA processing related to synthesis and/or secretion of the protein. Regulation of the production of CSF-1 may be an important physiological process in hematopoiesis and macrophage functioning.     

"A La Carte" treatment of portal hypertension: Adapting medical therapy to hemodynamic response for the prevention of bleeding

We report the results of adapting medical therapy to the monitoring of hemodynamic response in the prevention of a first variceal bleeding or rebleeding in patients with cirrhosis. Hepatic venous pressure gradient (HVPG) was measured before and after propranolol was initiated. The patients were considered responders if HVPG decreased below 12 mm Hg or at least 20% as compared with baseline value. If patients were not responders, isosorbide-5 mononitrate (I-5MN) was added, and a third hemodynamic study was performed. Thereafter, the patients were followed for a mean of 28 months. Thirty-four consecutive patients were treated to prevent a first bleeding episode in 20 patients and a rebleeding in 14 patients. HVPG value was initially 19.8 +/- 4.6 mm Hg and decreased to 17.6 +/- 5.7 mm Hg (P <.05) after propranolol alone. Thirteen patients (38%) were responders to propranolol. I-5MN improved hemodynamic response in 7 cases. Among these 20 (59%) hemodynamic responders, only 2 (10%) experienced variceal bleeding, as compared with 9 of 14 (64%) nonresponders (P <.05). Using multivariate analysis, only hemodynamic response was found to have an independent predictive value for the risk of variceal bleeding. In conclusion, hemodynamic response to drug therapy identifies patients who are efficiently protected from variceal bleeding as well as nonresponders in whom an alternative treatment should be considered.     

Histocompatible unrelated volunteer donors compared with HLA nonidentical family donors in marrow transplantation for aplastic anemia and leukemia

We treated 14 patients by transplantation of marrow from unrelated volunteer donors. Eight patients had severe aplastic anemia, 3 had chronic granulocytic leukemia, and 3 had Fanconi's anemia. The results are compared with those of a group of 14 similar patients transplanted concurrently from human leukocyte antigen (HLA)-mismatched family members: Sustained engraftment was achieved in 8 of 14 patients in both groups; one additional patient survived with autologous marrow reconstitution following an unrelated donor transplant. In the unrelated donor group, 6 of 9 evaluable patients developed grade III through IV acute graft-v-host disease, as compared with 4 of 9 patients after family-mismatched transplants. Overall survival was similar in the two groups. In the unrelated donor group 4 of 14 (29%) patients survived (median survival 1,299 days) as compared with 5 of 14 (36%) in the mismatched-family donor group (median survival 808 days). In both groups, patients with HLA phenotypically matched donors fared better than those with donors who were mismatched for one or more HLA antigen. Of the patients transplanted from HLA phenotypically matched donors 6 of 12 patients (50%) survived, as compared with 3 of 16 patients (19%) transplanted from HLA-mismatched donors. We conclude that unrelated donor bone marrow transplantation (BMT) should be considered in those cases of leukemia or bone marrow failure in which the chance of cure using conventional therapy is remote and a HLA genotypically or phenotypically matched family donor is not available.     

Brain electrical activity during combined hypoxemia and hypoperfusion in anesthetized rats.

In order to investigate the effects of moderate hypoxemia on brain electrical activity and the consequences of an altered cerebro-vascular response to hypoxemia, we recorded changes in electrical activity of the brain in anesthetized rats following unilateral carotid artery ligation (UCAL). In these animals, on the clamped side, cerebral blood flow, whilst normal during normoxia, shows less augmentation during hypoxemia. Six anesthetized (Halothane) Sprague-Dawley rats with UCAL were studied during 20 min periods of baseline (FI(O(2))=30%), hypoxemia (FI(O(2))=9.5%) and recovery (FI(O(2))=30%): mean arterial pressure of oxygen (PA(O(2))) achieved was 177.0, 37.6 and 160.1 mmHg, respectively. A significant decrease in the frequencies of the ECoG was observed bilaterally during hypoxemia: centroid frequency (fc)=3.37+/-0.14 and 2.85+/-0.13 Hz on the intact and clamped hemisphere respectively during hypoxemia versus fc=4.09+/-0.20 Hz (mean+/-S.E.M.) during baseline, which was not reversed during recovery (3.27+/-0.11 Hz) (ANOVA, P<0.01). The total power of the signal (Pw) was unaffected on the intact hemisphere but diminished on the clamped side during hypoxemia. Our results show that a significant slowing of ECoG is observed during hypoxemia of moderate intensity (40 mmHg) even when cerebro-vascular response to hypoxemia is preserved and that total power of the ECoG signal is severely diminished when the cerebro-vascular response to hypoxemia is impaired.     

Six point mutations that cause factor XI deficiency

We have identified six novel types of mutation that cause factor XI deficiency, an inherited bleeding disorder. Two are point mutations that interfere with the normal splicing of exons in the mRNA and four are point mutations that result in amino acid substitutions. One of these amino acid substitutions (Asp 16-->His) is near the amino terminal end of the protein. The other three amino acid substitutions (Leu 302-->Pro, Thr 304-->Ile, and Glu 323-->Lys) are in the fourth apple domain, a region that mediates dimerization of identical subunits of factor XI. All four amino acid substitutions cause a reduction in the amount of factor XI secreted from cells grown in vitro.     

Ultrastructural demonstration of tubular inclusions coinciding with von Willebrand factor in pig megakaryocytes

The appearance of von Willebrand factor (vWF) in bone marrow megakaryocytes was studied by standard electron microscopy (EM) and immuno-EM using an original purification technique. Eighty percent pure megakaryocytes were isolated from porcine rib bone marrow using Percoll gradients followed by counterflow centrifugation. Activation was prevented by prostacyclin and prefixation with low concentrations of glutaraldehyde. In early megakaryoblasts, standard EM revealed the presence of tubular structures in the small vesicles located in the Golgi area, in the small immature alpha-granules and in the rare mature alpha-granules. Immunolabeling for vWF was simultaneously observed in small vesicles and small alpha-granules, mainly in the Golgi zone. In mature megakaryocytes, standard EM showed that tubular structures were numerous, regularly spaced, and aligned in parallel. Immunolabeling for vWF was intense, restricted to the alpha-granules, and distributed in a similar manner to porcine platelets. Gold particles were located eccentrically at one pole of the alpha-granule, labeling only its periphery or outlining one side of an elongated granule. Tubule profiles could be seen underlying the immunolabeling and were usually located at one side of the granule. In conclusion, this study demonstrates the presence of tubular structures in megakaryocyte alpha- granules, their association with vWF, and the appearance of both in the Golgi-associated vesicles.     

Type of destruction of the neurosecretory regions of the crabs Carcinus maenas (L.) and C. mediterraneus Czerniavsky parasitized by Sacculina]

Histological study of the central nervous system in two species of Carcinus parasitized with Sacculina carcini revealed marked disorganization of neural structures. Neurosecretory areas appear to be destroyed in two ways. (1) By a direct action of the Sacculina roots, which surround what appear to be neurosecretory cells, the roots appearing first as open gutter-like tubes (i.e., U-shaped in cross-section) and then as closed tubes (annular in section). This action occurs mainly in the ventral ganglionic mass, which is always invaded by the parasite. (2) Indirectly, i.e., in the absence of contact with Sacculina roots; this action is especially marked in the brain and eyestalks. Two types of modifications related to the absence or presence of Sacculina roots have been detected in the sinus gland, i.e., a reduction in the storage of neurosecretory material, and inhibition of itsdischarge. Various hypotheses are proposed to explain the indirect destruction of neurosecretory cells and the alterations in the sinus gland.