Effects of raloxifene and alendronate on non-enzymatic collagen cross-links and bone strength in ovariectomized rabbits in sequential treatments after daily human parathyroid hormone (1-34) administration.

This study investigated the effects of raloxifene and alendronate to follow parathyroid hormone (PTH) on bone collagen and biomechanical properties in ovariectomized rabbits. Sequential treatments of raloxifene and alendronate after hPTH(1-34) treatment improved biomechanical properties with and without bone collagen improvement, respectively. INTRODUCTION: The standard sequential treatment to follow human parathyroid hormone (hPTH) (1-34) therapy for osteoporosis has yet to be determined. The objective of this study was to compare the effects of raloxifene and alendronate treatments to follow daily hPTH(1-34) treatment on non-enzymatic collagen cross-links, bone mass, and bone strength in ovariectomized (OVX) rabbits. METHODS: From 3 months after ovariectomy, seven month-old female New Zealand white rabbits were given either vehicle or hPTH(1-34) (8 µg/kg/day), once daily for 5 months. After hPTH(1-34) treatment, the hPTH(1-34)-treated animals were divided into two groups, and given raloxifene (10 mg/kg, daily) orally or alendronate (100 µg/kg, twice weekly) subcutaneously for 5 months. We evaluated bone mineral density (BMD), bone structural parameters, advanced glycation end product (AGE) content in collagen, and bone mechanical parameters including intrinsic parameters in the femur. RESULTS: Raloxifene (hPTH/RLX) and alendronate (hPTH/ALN) to follow hPTH(1-34) increased cortical thickness, maximum load, and maximum stress and decreased endocortical surface in the diaphysis, in addition to increasing total BMD in the distal metaphysis. Decreased trabecular AGE, pentosidine, and homocysteine contents and increased toughness and breaking energy were noted with hPTH/RLX treatment only. With hPTH/ALN treatment, no effects on non-enzymatic collagen cross-link AGEs were noted although increases in stiffness and elastic modulus were observed. CONCLUSION: These results suggest that sequential treatments with hPTH(1-34) and antiresorptive drugs (raloxifene and alendronate) have a beneficial effect on bone mass and biomechanical properties in OVX rabbits.

Changes in the contents of enzymatic immature, mature, and non-enzymatic senescent cross-links of collagen after once-weekly treatment with human parathyroid hormone (1-34) for 18 months contribute to improvement of bone strength in ovariectomized monkeys.

UNLABELLED: Improvements in total content of enzymatic cross-linking, the ratio of hydroxylysine-derived enzymatic cross-links, and non-enzymatic advanced glycation end product cross-link formation from once-weekly administration of hPTH(1-34) for 18 months in OVX cynomolgus monkeys contributed to the improvement of bone strength. INTRODUCTION: Parathyroid hormone (PTH) is used for the treatment of osteoporosis. To elucidate the contribution of material properties to bone strength after once-weekly treatment with hPTH(1-34) in an ovariectomized (OVX) primate model, the content of collagen and enzymatic immature, mature, and non-enzymatic cross-links, collagen maturity, trabecular architecture, and mineralization in vertebrae were simultaneously estimated. METHODS: Adult female cynomolgus monkeys were divided into four groups (n = 18-20 each) as follows: SHAM group, OVX group, and OVX monkeys given once-weekly subcutaneous injections of hPTH(1-34) either at 1.2 or 6.0 µg/kg (low- or high-PTH groups) for 18 months. The content of collagen, enzymatic and non-enzymatic cross-linking pentosidine, collagen maturity, trabecular architecture, mineralization, and cancellous bone strength of vertebrae were analyzed. RESULTS: Low-PTH and high-hPTH treatments increased the content of enzymatic immature and mature cross-links, bone volume (BV/TV), and trabecular thickness, and decreased pentosidine, compared with the OVX group. Stepwise logistic regression analysis revealed that BV/TV, the content of total enzymatic cross-links, and calcium content independently affected ultimate load (model R (2) = 0.748, p < 0.001) and breaking energy (model R (2) = 0.702, p < 0.001). BV/TV was the most powerful and enzymatic cross-link content was the second powerful determinant of both ultimate load and breaking energy. The most powerful determinant of stiffness was the enzymatic cross-link content (model R (2) = 0.270, p < 0.001). CONCLUSION: Once-weekly preventive administration of hPTH(1-34) increased the total contents of immature and mature enzymatic cross-links, which contributed significantly to vertebral cancellous bone strength.

Raloxifene ameliorates detrimental enzymatic and nonenzymatic collagen cross-links and bone strength in rabbits with hyperhomocysteinemia.

UNLABELLED: We demonstrate a reduction in enzymatic divalent immature and trivalent pyridinium cross-links and an increase in the nonenzymatic cross-link, pentosidine (Pen), in rabbits with methionine (Met)-induced hyperhomocysteinemia. Such detrimental cross-link formation in bone was ameliorated by raloxifene (RLX) treatment. INTRODUCTION: Collagen cross-links are determinants of bone quality. Homocysteine (Hcys) interferes with collagen cross-linking. Because RLX is thought to ameliorate bone quality, we investigated whether RLX ameliorated hyperhomocysteinemia-induced cross-link abnormalities using a Met-rich diet rabbit model. METHODS: We divided New Zealand white rabbits into six groups (n = 6 per group): baseline control, sham operation, sham + 1% Met diet, ovariectomy (OVX), 1% Met diet + OVX, OVX + RLX (10 mg/kg/day), and 1% Met diet + OVX + RLX. RLX was administered for 16 weeks. We measured the amount of enzymatic immature and mature pyridinium cross-links and the nonenzymatic cross-link, Pen, and correlated the cross-link content to bone strength. RESULTS: Hcys levels were significantly higher in the Met diet groups than in the normal diet groups. Met-fed rabbits with or without OVX showed a significant reduction of enzymatic cross-links, whereas an increase in Pen was observed in Met-fed rabbits with OVX. The cross-link content of the RLX-treated Met-fed rabbits with OVX was restored to similar levels as the sham group, accompanied by an improvement of bone strength. CONCLUSION: These results demonstrate that hyperhomocysteinemia reduced bone strength via a reduction of enzymatic cross-links and an increase of nonenzymatic cross-links. RLX may ameliorate hyperhomocysteinemia-induced detrimental cross-linking in rabbits with OVX and may improve bone strength via the amelioration of collagen cross-links.

[Gamma knife treatment of AVM of the basal ganglia and thalamus].

Arteriovenous malformatios (AVMs) in the basal ganglia (BG) and thalamus (Thal) are difficult to treat by microsurgery or intravascular embolization alone, and the role of stereotactic gamma radiosurgery (gamma knife) of these AVMs is discussed. We have treated 324 cases of AVM with gamma knife since May 1991, and in 71 of these cases (19%) the AVM was in the BG or Thal. The results of gamma radiosurgery on AVMs of the BG and Thal were compared with the results of treating AVMs at other intracranial locations by gamma radiosurgery. The nidi were small (mean diameter: 16.4 mm), and they were treated with a mean maximum dose of 36.4 Gy and marginal dose of 19.9 Gy. The results were evaluated angiographically in 39 (55%) of the 71 cases, with a mean follow-up period of 23 months. The complete obliteration rate of AVMs in the BG and Thal 1 and 2 years after treatment was 54.3% and 92.0%, respectively, and the rate at the other locations was 42.9% and 76.0%, respectively. Adverse effects of this treatment in the AVM cases overall were rebleeding from the nidus in 5 cases (1.5%) and radiation necrosis in 4 cases (1.2%). In conclusion, AVMs of the BG and Thal were effectively and safely treated with the gamma knife, and stereotactic radiosurgery is a definitive alternative treatment for deep seated AVMs.

Intraarterial perfusion of the hindlimb with pyridoxalated hemoglobin polyoxyethylene conjugate solution in anesthetized dogs.

To evaluate the potential clinical usefulness of a modified hemoglobin, pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), the hindlimb vascular bed was perfused with PHP solution while monitoring tissue oxygen tension (PtO2) in anesthetized dogs. The hindlimb region was perfused through the external iliac artery with a roller pump at a varying perfusion rate. PtO2 was measured using a PO2-monitoring probe inserted into the gracial muscle. After surgical preparation for perfusion, the iliac arterial flow rate was 19.9 +/- 5.6 ml/min, and baseline PtO2 was 38.4 +/- 1.3 mm Hg. Perfusion with autologous arterial blood with the pump increased PtO2 and perfusion pressure (PP) in a perfusion rate-dependent manner. Perfusion with PHP solution at 20 ml/min decreased PtO2 from the initial baseline level, but an increase in the flow rate to 40-55 ml/min restored or induced an elevation of PtO2. Results demonstrated that PHP solution can deliver oxygen to local tissue and maintain tissue oxygen tension at the same level as autologous arterial blood at a high enough flow rate.

Magnetic resonance angiography of arteriovenous malformation in the thalamus.

A comparative study of magnetic resonance angiography and conventional angiography of arteriovenous malformation in the thalamus showed that both methods clearly visualized the feeding arteries: perforating branches of the posterior cerebral artery, posterior choroidal artery and lenticulostriate artery. Draining veins such as the internal cerebral vein were also demonstrated well.

Interstitial hyperthermia of malignant brain tumors by an implant heating system using stereotactic techniques.

Interstitial hyperthermia of malignant brain tumors has been produced by a heated ferromagnetic implant with a low Curie point. Induction heating of the implant, which is stereotactically implanted in a tumor, is obtained by eddy currents in a high-frequency magnetic field. Safe, repeated and long-term treatment of 35 cases of malignant brain tumors has been done using this system. The overall response rate was 31.4%, but the rate for metastatic brain tumors, deep-seated gliomas and others were 50.0, 36.8 and 33.3%, respectively. Deep-seated gliomas were more effectively treated than superficial gliomas by combination with radiation therapy. The common pathological finding was a clearly demarcated coagulative necrosis of ellipsoid shape around the implant.

Interstitial hyperthermia of malignant brain tumors by implant heating system: clinical experience.

An implant heating system using a ferromagnetic implant with low Curie temperature has been developed for treating human brain tumors. Safe and repeated hyperthermia was possible over periods averaging ten weeks in 23 out of 25 patients with malignant brain tumors without development of major side effects. Evaluation of the effects of this new treatment is still preliminary. Overall response rate was 34.8%. However, five of thirteen cases of malignant glioma and two of five cases of brain metastasis were responded well to interstitial hyperthermia given with or without irradiation. Pathological findings common to the treated tumors were circumscribed, ellipsoid shape of coagulation necrosis around the implant. Degeneration of tumor cells, hemorrhage, vascular stasis and thrombosis were found adjacent to the necrosis. In the future, a combination of interstitial hyperthermia with brachytherapy and chemotherapy may offer improved local control of brain tumor.

[Interstitial hyperthermia of malignant gliomas with implant heating system].

Twenty four cases of malignant gliomas, histologically 12 glioblastomas, 10 astrocytoma GIII and 2 astrocytoma GII, were treated by interstitial hyperthermia with Implant Heating System (IHS). IHS has three major parts, generator of high frequency (240KHz), magnetic coil and metal implant manufactured from FePt alloy. Theoretically the brain tumor can be heated by heat conduction through the heated implants. Several implants were placed inside the brain tumor directly by operation, or by CT stereotactic procedure. The patients were divided into two groups according to the tumor location as (A) in cortical or subcortical region (13 cases) and (B) in thalamus or basal ganglia (11 cases). Hyperthermia, 60 minutes each, 2 to 3 times per week, was safely repeated in all the cases. External irradiation was always combined with hyperthermia in most of the cases and with chemotherapy in some of them. Follow-up CTs demonstrate a remarkable response in many cases of B group. In fact ICR, 4PR and 3MR were achieved in this group, resulting in 45.5% of the response. In contrast gliomas in A group showed a less favorable response, resulting in 23.1% of the response (3 PRs in 13 cases). Although the overall response rate was not so high, it seems to be encouraging that gliomas in thalamus and basal ganglia, those which are usually unresectable, showed a good response. More favorable results can be expected by further improvement of the system and related techniques.

[Hyperthermia of metastatic brain tumor with implant heating system: a preliminary clinical results].

Metastatic brain tumors were treated by interstitial hyperthermia with an Implant Heating System, which consists of three major parts: ferromagnetic implant (thermoseed), generator of high frequency (240 KHz) and induction coil (30 cm in diameter). The implant is made of Fe-Pt alloy, 1.8 mm in diameter and 15 to 20 mm in length, whose Curie point is 68 - 69 degrees C. Seven cases of metastatic brain tumor, 5 from lung cancer, one from breast cancer and another from colon cancer, were involved in this study. One or several implants were placed inside the tumor by CT guided stereotaxis, or manually inserted at craniotomy. Interstitial hyperthermia at 44 - 46 degrees C was made by IHS for 30 to 60 minutes twice or three times a week. External irradiation was simultaneously combined with hyperthermia in 6 cases. Repeated, longterm hyperthermia (8 - 45 times) was possible in all cases except one, whose treatment was discontinued due to migration of the implant. No other serious side effect was found in any cases during and after the treatment. Repeated CT scans reveal complete response in 2, minor response in one and progression in 3 cases. Therefore this preliminary clinical study indicates that interstitial hyperthermia with IHS is very useful and promising method for treating intracranial metastases.

[Interstitial hyperthermia of malignant brain tumors using implant heating system (IHS)].

We have developed an implant heating system (IHS) for interstitial hyperthermia of brain tumors. IHS consists of three compartments: ferromagnetic implant with low Curie point, induction coil and generator to produce high frequency magnetic field. The device works as follows: It is heated up to a Curie temperature (Tc) by Eddy current under the magnetic field. Heat generated in the implant is conducted to the tumor tissue into which it has been implanted. To evaluate the effect of this hyperthermia, a brain tumor model was produced by innoculation of VX2 tumor cells and treated either by hyperthermia with IHS alone, chemotherapy with ACNU alone, or with a combination of both. The longest survival was obtained by the combined treatment, and significant prolongation of survival was found in the single treatment groups. In the Phase I clinical trial, one or several implants (1.8 mm X 15 mm, Tc = 68 degrees C) made of Fe-Pt alloy were placed in the tumor by CT guided stereotactic procedure, or manually during craniotomy. Hyperthermia of above 42 degrees C for 30 to 60 minutes twice a week was brought about in ten cases of malignant brain tumor. CT evaluation was made in nine cases treated for more than ten times in this way. Five out of the nine cases responded to this hyperthermia with irradiation. In conclusion, a safe, repeated and longterm treatment was possible without significant side effects. The hyperthermia with IHS may also be applicable to benign intracranial tumors and neoplasms in other part of body as well.

Insulin resistance is associated with reduced fasting and insulin-stimulated glycogen synthase phosphatase activity in human skeletal muscle.

Insulin-stimulated glycogen synthase activity in human skeletal muscle correlates with insulin-mediated glucose disposal rate (M) and is reduced in insulin-resistant subjects. We have previously reported reduced insulin-stimulated glycogen synthase activity associated with reduced fasting glycogen synthase phosphatase activity in skeletal muscle of insulin-resistant Pima Indians. In this study we investigated the time course for insulin stimulation of glycogen synthase and synthase phosphatase during a 2-h high-dose insulin infusion (600 mU/min per m2) in six insulin-sensitive caucasians (group S) and in five insulin-resistant Pima Indians (group R). Percutaneous muscle biopsies were obtained from the quadriceps femoris muscle after insulin infusion for 0, 10, 20, 40, and 120 min. In group S, insulin-stimulated glycogen synthase activity increased with time and was significantly higher than in group R. In group S, synthase phosphatase activity increased significantly by 25% at 10 min and then decreased gradually. No significant change in synthase phosphatase was seen in group R and activity was lower than group S at 0 to 20 min. These data suggest that a low basal synthase phosphatase activity and a defect in its response to insulin explain, at least in part, reduced insulin stimulation of skeletal muscle glycogen synthase associated with insulin resistance.

Interstitial hyperthermia of brain tumors by stereotactically implanted heating system.

Interstitial hyperthermia of brain tumors has been made by an implanted heating system using a metal implant with low Curie temperature, which was stereotactically implanted in a tumor. Induction heating of the implant was obtained by eddy current in a magnetic field. Safe, repeated and long-term treatment of 25 cases of brain tumor has been made with this system. Among 22 evaluable cases, 10 responded to hyperthermia alone or in combination with radiation therapy. There were 3 complete remissions, 5 partial remissions and 2 minor responses. The effectiveness of this treatment has also been evaluated by pathological examination.

Interstitial hyperthermia of experimental brain tumor using implant heating system.

New experimental system of induction hyperthermia for brain tumor using ferromagnetic implant with low Curie point has been developed. The metal implant is cylindrical needle and made of Fe-Pt alloy with low Curie point suitable for hyperthermia (50-60 degrees C). Induction coil and generator which produce maximum power of 200W and variable frequency of 100-500kHz, yielding magnetic power of 16.7Oe, have been developed. Interstitial hyperthermia was made on rat brain tumor model (T9 gliosarcoma) by this system. Significant effects of single hyperthermia (45 degrees C for 30 minutes) were observed by the extension of life span and morphological changes of the tumor.

[The effect of hyperthermia and antitumor drugs on brain tumor cell lines].

The effects of heat and antitumor drugs on malignant brain tumor cell lines were studied. A human glioblastoma cell line (SKMG1) and rat malignant brain tumor cell lines (T9, EB 679 and TR 481) were used in this experiment. Five different modalities of treatment with heat and drugs were used as follows: (Group 1) exposure to heat alone at 42 degrees C for one hour; (Group 2) exposure to antitumor drug alone for one hour (ACNU 2.5 or 5 micrograms/ml, ACR 0.02 micrograms/ml and CDDP 1 microgram/ml); (Group 3) simultaneous exposure to heat at 42 degrees C and drug for one hour; (Group 4) heat at 42 degrees C given first for one hour, followed by one hour exposure to drug one hour later ("preheating"); (Group 5) drug given first for one hour, followed by one hour exposure to heat at 42 degrees C one hour later ("postheating"). After each treatment, the inhibition rate at 4 days was evaluated and compared for each group. A synergistic effect was observed in Group 3. For example, when T9 cells were exposed to ACNU and to heat at 42 degrees C at the same time for one hour, inhibition rate was 78%, while the rates for Group 1 and Group 2 were 7% and 21%, respectively. The cytotoxicity of simultaneous treatment with antitumor drugs (ACNU, ACR and CDDP) and hyperthermia at 42 degrees C was apparently superior to that of other treatment modalities.

Magnetic induction hyperthermia for brain tumor using ferromagnetic implant with low Curie temperature. I. Experimental study.

Experimental study was made on magnetic induction hyperthermia for brain tumor using ferromagnetic implant with low Curie temperature. Thermoseed (implant) was made of nickel-palladium alloy, which was confirmed to produce enough heat by eddy current and also to have low Curie point between 43 degrees C-58 degrees C. Using this implant heating system, the effect of hyperthermia on normal rat brain and intracutaneously inoculated rat gliosarcoma (T9) were studied. Heat conduction from seed was twice as much in tumor tissue as in normal brain. It was also found that the intradermal brain tumors were completely diminished within 4 weeks by single local hyperthermia at 45 degrees C for 60 min.