Influence of the cumulative effect of zoledronic acid on periodontal microcirculation in rats.

PURPOSE: To evaluate the effect of repeated administration of zoledronic acid (ZA) on the development and severity of osteonecrosis of the jaws. METHODS: In the experiment, 36 rats were used, which were divided into 4 groups: group 1 was injected with saline for 6 weeks, group 2 was injected with ZA once, group 3 was injected zoledronic acid for 3 weeks once a week, group 4 was injected with ZA for 6 weeks once a week. While taking medications, the tooth was removed. The volumetric blood flow rate was studied using laser and high-frequency ultrasound Doppler in the area of the periodontium of an extracted tooth in rats with the application of acetylcholine. Bone tissue was examined out using CBCT. RESULTS: In group 2, there was a violation of blood flow in the mucous membrane, bone microcirculation, but no reliable data was obtained in the bone defect in comparison with group 1. In groups 3 and 4, there was significantly disrupted blood flow. This led to an increase of the osteonecrosis (maximum at the 4th group), which was confirmed by data obtained using CBCT. An inverse relationship was observed between the blood flow of bone tissue and the size of the defect after tooth extraction. CONCLUSION: The introduction of ZA in a dose-dependent fashion resulted in impaired endothelial vasodilation and impaired blood flow to extraction sockets. These findings might explain the development of osteonecrosis of the mandible following removal of a first molar.

Disorders of microcirculation in the mechanism of bisphosphonate osteonecrosis: preliminary study in rats.

We investigated the possibilities of angioprotection and the reduction of osteonecrosis in rats that had been given bisphosphonates. In our experiment, 27 rats were divided into three groups: Group 1 was injected with saline; Group 2 was given zoledronic acid for six weeks; and Group 3 was given zoledronic acid for six weeks, with added doses of sulodexide after three weeks. After that we constructed a model of how the teeth should be extracted. The velocity of linear blood flow in the periodontal area of an extracted tooth in rats was studied using laser and high-frequency Doppler ultrasound (with the application of the vasoactive substance acetylcholine 3% for 1min). We evaluated changes in the structure of the bony tissues of the head using computed tomography, comparing the control group with the saline group. A rapid reduction in microcirculation was detected during the use of zoledronic acid for six weeks. A smaller reduction in microcirculation was detected after three weeks of treatment with sulodexide and zoledronic acid. There was a reduction in blood flow in the mucous membranes and, to a greater extent, in bony tissue. Zoledronic acid causes significant impairment of the periosteal blood flow to the mucous membranes because of a complex of disorders, which includes both the cellular component (impaired endothelium-dependent vasodilation of the mucous membrane vessels) and by reducing the intensity of microcirculation in the mucous membranes and bony tissues. Sulodexide, however, improves the restoration of blood flow and reduces the severity of osteonecrosis.

[Calcifying myxoma of the right heart with development of thromboembolic pulmonary hypertension]. / Obyzvestvlennaia miksoma pravykh otdelov serdtsa s razvitiem tromboémbolicheskoi legochnoi gipertenzii.

Two rare cases of calcified myxomas of the right heart (multiple myxomas of the right atrium and tricuspid valve and myxoma of the right ventricle originating from the subvalvular structures) are described. Both patients were operated, tumour and the tricuspid valve were removed and valve prosthesis was made. At necropsy changes characteristic of pulmonary hypertension resulting from the recurring thromboembolism by a tumourous tissue were found in one case.

[Hemangioma of the heart]. / Gemangioma serdtsa.

A rare observation of a cardiac benign tumour haemangioma in 17-year-old male is presented. The tumour was located in the exitus aperture of the right ventricle, originated from the interventricular septum, prolapsed into the lumen and narrowed it. Successful resection of the tumour was performed.

[Cardiac myxoma recurrence with the formation of tumors in both atria]. / Retsidiv miksomy serdtsa s formirovaniem opukholei oboikh predserdii.

A case of heart myxoma recurrence 1.5 years after the removal of the left atrium primary tumour is described. Recurring tumour was represented by myxoma of both atria which was removed as a single block with a part of the interventricular septum. Both primary tumour and those of the left and right atrium have the structure of benign heart myxoma. However, the presence of the infiltrative growth into the interventricular septum allows one to consider the recurrent tumour as a borderline, locally destructive one.

[The surgical treatment of multiple myomas of the left heart]. / Khirurgicheskoe lechenie mnozhestvennykh miksom levykh otdelov serdtsa.

5 patients with multiple left heart myxomas have been followed for 30 years. There were 4 females and 1 male at the age of 20-50 years. Two-dimensional echocardiography was used for the proper diagnosis in all cases. Open-heart surgery is the only possible method of treatment in such a situation. All the patients have been successfully operated on. To prevent the recurrence the resection of myxomas with a part of interatrial septum and endocardium was performed. The trans-sternal approach is the optimal one for the surgery of myxomas.

[Mitral commissurotomy in children and adolescents]. / Mitral'naia komissurotomiia u detei i podrostkov.

The article analyses the results of operations on 184 children and adolescents with rheumatic mitral stenosis. "Pure" mitral stenosis was diagnosed in 48.4% of patients, valvular stenosis in combination with relative tricuspid insufficiency--in 23.4%, mitral valvular disease with I degree regurgitation--in 26%, and mitral stenosis combined with aortic valvular diseases which did not need surgical correction--in 2.2% of patients. Transventricular instrumental commissurotomy was performed in 73.9% of patients, digital commissurotomy--in 7.1%, open mitral commissurotomy under conditions of extracorporeal circulation--in 3 patients. Adequate distention of the mitral orifice was achieved in 84% of patients, incomplete separation--in 16%. Complications occurred after the operation in 29.7% of patients. Traumatic mitral insufficiency developed in 38 patients. The immediate results were good in 84.2%, satisfactory--in 9.9%, and poor--in 3.2% of patients. Hospital mortality was 2.7%.

[Mitral commissurotomy during pregnancy]. / Mitral'naia komissurotomiia vo vremia beremennosti.

Relying on studies into the features of the gestation course, immediate and late results, instrumental investigation findings in 91 patients with mitral stenosis prior to a surgery and in the readaptive period, indications and relative contraindications for mitral commissurotomy during pregnancy were specified and supplemented. Differential strategy was also developed for delivery of such patients.

[Surgical treatment of endocarditis following heart valve prosthesis]. / Khirurgicheskoe lechenie proteznogo éndokardita.

Experience of many years in surgical treatment of prosthetic valve endocarditis (RVE) is analyzed. Patients whose condition was serious were operated on for a second time: 91.6% had preoperative functional class IV, in half of them circulatory disorders were of stage IIB--III; 62.4% were subjected to reoperation for emergency indications. Twenty-five reoperations were performed for early PVE with 52% hospital mortality, 23 reoperations-for late term PVE with mortality of 30.4%. The most frequent cause of PVE was staphylococcal infection which showed a tendency to increase in the recent years. In early PVE the severity of the condition in the recent years. In early PVE the severity of the condition was due to sepsis and intoxication, in late-term PVE it was caused by disorders of hemodynamics which were usually induced by dysfunction of the prosthesis. The results of surgical management of PVE depended on the severity of the patient's condition before the operation, timely performance of the operation, and the efficacy of antibacterial therapy.

[Reoperations after insertion of heart valve prosthesis]. / Povtornye operatsii posle protezirovaniia klapanov serdtsa.

The authors analysed 167 repeated operations after heart valve prosthetics, which were conducted from 1978 to 1988. The operations were undertaken for the second time mainly in a severe contingent of patients. The reasons for the repeated operations were specific complications according to which 2 groups of patients were set apart: with dysfunction of the prosthesis of noninfectious origin and with prosthetic endocarditis. Study showed that repeated operative intervention undertaken in time reduces considerably its risk and produces a stable positive effect in most cases.