(99m)Tc-sestamibi uptake in rat skeletal muscle and heart: physiological determinants and correlations.

The lipophilic cationic radiotracer (99m)Tc-sestamibi, known to be concentrated within mitochondria, is widely used for myocardial perfusion and to a lesser extent for muscle metabolism imaging. However, the exact distribution pattern in skeletal muscle has not been yet studied in detail. The present study aims to investigate the (99m)Tc-sestamibi uptake in rat skeletal muscle and myocardium in relation to their metabolic characteristics. (99m)Tc-sestamibi was i.v. administered in twenty adult male Wistar rats and uptake, as percent of injected dose per tissue gram (%ID/g), in the myocardium, soleus, extensor digitorum longus and gastrocnemius muscles was assessed 2 h after the injection. Muscle uptake was also correlated with myocardial uptake, muscle weight and body weight. Skeletal muscle (99m)Tc-sestamibi uptake was a small (9-16 %) fraction of that found in myocardium (1.71+/-0.63 %ID/g). Among the three hindlimb muscles considered, the slow-oxidative soleus muscle showed the highest uptake (0.28+/-0.16 %ID/g). Metabolically diverse parts of the gastrocnemius muscle showed different uptake. Skeletal muscle uptake was positively correlated with myocardial uptake and both were negatively correlated with tissue and body weight. Skeletal muscle and myocardium (99m)Tc-sestamibi uptake is related to their metabolic profile. Myocardium, with an exceptional rich mitochondrial concentration, shows much higher (99m)Tc-sestamibi uptake compared to skeletal muscles. Among muscles, uptake is dependent on their mitochondrial content. Evidence of matching exists between myocardial and muscle uptake, and both are size-dependent.

Effect of aerobic training on 99mTc-methoxy isobutyl isonitrile (99mTc-sestamibi) uptake by myocardium and skeletal muscle: implication for noninvasive assessment of muscle metabolic profile.

AIM: The effect of long-term endurance training on skeletal muscle and myocardial uptake of (99m)Tc-sestamibi, a radiopharmaceutical accumulating in the mitochondria, was investigated. METHODS: Twenty-six Wistar rats were divided into a trained (5 days week(-1) endurance running for 14 weeks) and an untrained group. On completion of training, (99m)Tc-sestamibi was administered and, 2 h post-injection, the myocardium and the soleus, extensor digitorum longus (EDL) and medial gastrocnemius (MG) muscles were removed for the measurement of cytochrome c oxidase (CCO) activity and (99m)Tc-sestamibi uptake. Tissue (99m)Tc-sestamibi kinetics was preliminarily studied in 16 other rats for up to 2 h post-injection. RESULTS: Two hours post-injection (99m)Tc-sestamibi uptake was either stable (myocardium) or still rising (skeletal muscles). Both CCO activity and (99m)Tc-sestamibi uptake decreased in the same order (myocardium, soleus, EDL, MG) in the tissues examined. The CCO activity of the EDL and MG muscles was higher (P < 0.05) in the trained compared to the untrained group. (99m)Tc-sestamibi uptake in the soleus and EDL muscles was higher (P < 0.05) in the trained compared to the untrained rats, whereas the difference in MG was marginally significant (P = 0.06) in favour of the trained group. CONCLUSIONS: Long-term endurance training, resulting in elevated skeletal muscle CCO activity, is also associated with a similar increase in (99m)Tc-sestamibi uptake. This finding suggests that (99m)Tc-sestamibi could be used in imaging assessment of skeletal muscle metabolism with possible applications in both clinical and sports medicine settings.

Estrogen effect on some enzymes in female rats after downhill running.

The study investigates the effect of administered estrogen on plasma creatine kinase (CK) and lactate dehydrogenase (LD) levels in female ovariectomized rats after downhill running. Rats ovariectomized before sexual maturity were subcutaneously implanted with pellets containing 17 beta-estradiol or placebo. Three weeks later they were subjected to a 90-min intermittent downhill running protocol. Blood samples were obtained from the jugular vein immediately after and 72 h after exercise for determination of plasma CK, LD and 17 beta-estradiol levels. A two-way analysis of variance was used for data evaluation. Plasma CK and LD levels were significantly lower (p<0.05) in the estrogen-supplemented, ovariectomized animals which suggests that less muscle damage occurred compared to the controls immediately and 72 h after exercise. Estrogens may have a protective effect on muscle tissue possibly due to their antioxidant and membrane stabilizing properties.

A decrease in soleus muscle force generation in rats after downhill running.

The purpose of the present study was to investigate the immediate and 48-hr post-exercise effects of eccentric contraction-biased exercise on the contractile properties of the soleus muscle in situ. Adult male Wistar rats were categorised into sedentary control rats (n = 10), rats studied immediately (n = 10), and rats studied 48 hours after the exercise (n = 10). The exercise protocol consisted of a 90-min intermittent downhill running (-16 degrees, 16 m/min) on a motor-driven treadmill. The contractile properties of the soleus muscle were recorded following i.p. chloral hydrate anaesthesia. Isometric twitch force (Pt), time-to-peak tension (TPT), half-relaxation time (1/2 RT), and tetanic force at stimulation frequencies of 40, 80, and 100 Hz were recorded. A low-frequency muscle fatigue protocol (stimulation at 4 Hz for 5 min) was applied to test for fatigability. The main findings indicated that Pt generation dropped both immediately and 48 hr after the exercise, while tetanic force was partially restored after 48 hr. Exercise-induced E-C coupling failure and contractile machinery disorganisation due to muscle injury are put forward as the main force reduction causes.

Epidermal nevus syndrome with development of a mandibular ameloblastoma.

Epidermal nevus syndrome (ENS) is a hamartoneoplastic syndrome characterized by the association of epidermal nevi with abnormalities in other organ systems. We report a 32-year-old woman with ENS that, in addition to cutaneous manifestations, showed red plaques on the maxillary and mandibular labial alveolar mucosa and a papillomatous lesion of the midline posterior hard palate. Radiographic examination of the jaws was noncontributory. Approximately 5 years later, a follicular ameloblastoma developed in the mandible. The tumor showed duct-like cystic spaces, continuity with the overlying epithelium, and globular myxomatous areas in the connective tissue. The palatal lesion was diagnosed as papilloma, whereas the maxillary plaques showed nonspecific mucositis. The association of ameloblastoma with ENS is discussed. This is the second case of ENS associated with ameloblastoma reported in the medical literature.

Restoration of spermatogenesis by follicle-stimulating hormone despite low intratesticular testosterone in photoinhibited hypogonadotropic Djungarian hamsters (Phodopus sungorus).

By exposing male Djungarian hamsters to short-day photoperiods, a hypogonadotropic condition resembling that of hypophysectomized animals can be achieved without resorting to surgery. By use of this animal model, differential effects of gonadotropins on spermatogenesis have been studied revealing that FSH selectively restimulates spermatogenesis up to the level of spermatids. In the present study, we investigated whether FSH (6 IU/day) also restores fertility in hamsters exposed to short-day photoperiods (8L:16D). Animals kept under long-day photoperiod (16L:8D) served as controls. After 8 wk under 8L:16D, gonads were involuted and the animals (n = 9-10 per group) were treated with FSH, or testosterone implants, or both for the following 33 days. An additional group received FSH for 33 days and, for the last 12 days only, FSH plus testosterone to induce copulatory and ejaculatory behavior. The implants caused no increase in intratesticular testosterone as compared to that in short-day controls. All males were paired with adult females for the last 5 days of treatment, and killed thereafter. Litter sizes were determined 22 days later. The examination of the testes by flow-cytometrical techniques revealed qualitatively normal spermatogenesis in animals receiving FSH, whereas testosterone caused an insignificant increase to a few round spermatids. In most FSH-treated animals, sperm were present in the epididymides. In hamsters receiving FSH along with testosterone, treatment resulted in restoration of full fertility as compared to long-day controls. Fertility was also restored in animals receiving testosterone only for the last 12 days of FSH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Techniques of surgical exposure of unerupted maxillary anterior teeth for orthodontic management]. / Technikes cheirourgikes apokalypses egkleiston ano prosthion dontion gia orthodontike elxe kai dieuthetese.

The problem of impaction of the maxillary anterior teeth can be solved under cooperation of the oral and maxillofacial surgeon and the orthodontist. In that way unerupted teeth which in the past were scheduled to be extracted, nowadays can be saved and take their place in the dental arch. There are various surgical techniques of exposure of unerupted anterior maxillary teeth, for orthodontic management. Decision of the most suitable for each individual case can be taken after careful analysis of the diagnostic data from the surgeon and the orthodontist taking under consideration the location of the unerupted tooth, the periodontal status and the patients' cooperation. In this paper reference is being made in different techniques of surgical exposure for orthodontic traction with regard to the maintaining of a good tooth-gingiva relationship. Same clinical cases are also presented.

[Application of granulate hydroxylapatite for mandibular augmentation]. / E epharmoge tou kokkode ydroxylapatite gia ten anypsose tes gnathikes akrolophias.

The already known surgical interventions for absolute induction of extensive mandibular atrophy, cannot be suggested as routine standardized methods. Use of Hydroxylapatite-ceramic for restoration of the atrophic alveolar process, shows several advantages; among those, simplicity of the operation use of local anesthesia, as well as very low percentage of unsuccessful interventions are taken into consideration. The clinical results of 102 cases are shown and discussed. Through the addition of H.A. ceramic in the field of preprosthetic surgery, there is a broadening of the spectrum of the therapeutic possibilities of patients with prosthetic problems to be expected.

[Treatment of impacted upper central incisor]. / Antimetopise egkleistou ano kentrikou tomea.

The impaction of the upper central incisor is a common problem for the clinical orthodontist. The correct diagnosis is a fundamental factor in trying of the alignment of this tooth in the dental arch. There are cases where treatment should be conservative and removing the responsible for the impaction factor is all need to be done, for the tooth to erupt. In other cases, however, surgical exposure and orthodontic traction are both necessary. Three cases with impaction of the upper central incisor are described as well as the treatment provided and a literature review of the above subject is presented.

Central odontogenic fibroma.

The article presents a case of central odontogenic fibroma occurring in the maxilla. The literature is reviewed, in the belief that a discussion of the controversial issues surrounding this neoplasm, its treatment and follow-up information, is warranted, due to the small number of cases (13) of this tumor that have been recognised and reported up to the present.

Peripheral ameloblastoma. Case report and review of the literature.

The clinical and histologic features of 16 cases of peripheral ameloblastoma are reviewed. One additional case of this unusual tumour, in a 76-year-old edentulous woman, is also described. This lesion arose on the mucosa of the upper alveolar crest and extended to the mucobuccal fold. It was painless with a dark-red granular surface. The lesion was excised surgically and no evidence of recurrence was seen 8 months later.