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Biomedical subjects

R Mazzeo

Publications and source records attributed to R Mazzeo.

8 recordsLinked to original sources
PubMed2000

Women at altitude: energy requirement at 4,300 m.

To test the hypotheses that prolonged exposure to moderately high altitude increases the energy requirement of adequately fed women and that the sole cause of the increase is an elevation in basal metabolic rate (BMR), we studied 16 healthy women [21.7 +/- 0.5 (SD) yr; 167.4 +/- 1.1 cm; 62.2 +/- 1.0 kg]. Studies were conducted over 12 days at sea level (SL) and at 4,300 m [high altitude (HA)]. To test that menstrual cycle phase has an effect on energetics at HA, we monitored menstrual cycle in all women, and most women (n = 11) were studied in the same phase at SL and HA. Daily energy intake at HA was increased to respond to increases in BMR and to maintain body weight and body composition. Mean BMR for the group rose 6.9% above SL by day 3 at HA and fell to SL values by day 6. Total energy requirement remained elevated 6% at HA [ approximately 670 kJ/day (160 kcal/day) above that at SL], but the small and transient increase in BMR could not explain all of this increase, giving rise to an apparent "energy requirement excess." The transient nature of the rise in BMR may have been due to the fitness level of the subjects. The response to altitude was not affected by menstrual cycle phase. The energy requirement excess is at present unexplained.

Adult↗
PubMed1998

Spaceflight downregulates antioxidant defense systems in rat liver.

Liver antioxidant enzyme activities, mRNA abundance, and glutathione (GSH) status were investigated in male Sprague-Dawley rats placed in an enclosure module aboard Space Shuttle STS-63 for 8 d (F, n = 6). F animals were compared to rats housed in an enclosure module on the ground (G, n = 9), which simulated the vibration and temperature conditions associated with launch and flight, and rats kept under conventional ground vivarium conditions in individual cages (V, n = 6). Spaceflight significantly decreased catalase, GSH reductase, and GSH sulfur-transferase activities in the liver (p < .05). Neither enzyme activity nor enzyme protein content of Cu-Zn and Mn superoxide dismutase (SOD) was affected by flight. The relative abundance of mRNA for Cu-Zn SOD and catalase was significantly decreased comparing F with G rats (p < .05). Spaceflight resulted in a dramatic decrease of liver GSH, glutathione disulfide, and total GSH contents (p < .01), which were accompanied by a lower gamma-glutamyl transpeptidase activity (p < .05). F rats showed a 47% (p < .05) increase in liver malondialdehyde concentration compared to G and V rats. Liver protein content was not affected by flight. These results indicate that spaceflight can downregulate antioxidant defense capacity and elicit an oxidative stress in the liver.

Animals↗
PubMed1996

[Polyostotic fibrous dysplasia. A clinical case report].

The authors present a severe case of polyostotic fibrous dysplasia in which there was considerable involvement of cranial bone and facial skeleton. Numerous lesions were present at the level of the long bones of limbs. Endocrine dysfunction was also present in the form of a hypophyseal adenoma secreting prolactin and ACTH. The concomitance of acromegaly or gigantism and/or hyperprolactinemia and polyostotic fibrous dysplasia has only been reported to date in a few cases in literature. The authors describe the appearance of the subject, correlating clinical photographs with X-rays. They report the clinical excursus of the patient characterised by the gradual increase in deformities which seriously jeopardized the patient's relational life, in particular the appearance of a bulk on the forehead and checks and the deformation of the symphyseal portion of the mandible with presence of interdental diastemata. The patient also complained diplopia, difficulty in chewing owing to the mobilisation of teeth, and increasing bone pain probably due to nerve compression by exuberant bone. It was not possible to perform corrective surgery owing to the patient's overall poor health conditions. In fact, dilatative cardiomyopathy which continued to worsen in spite of numerous forms of medical treatment resulted in the patient's death owing to cardiac decompensation. Even the attempt to treat the patient's primary endocrine dysfunction using bromocryptine and subsequently octreotide failed to produce positive results owing to the onset of collateral effects which led to the early suspension of treatment.

Biopsy↗
PubMed1994

A permissive role of corticosterone in an opioid form of stress-induced analgesia: blockade of opiate analgesia is not due to stress-induced hormone release.

The 100 inescapable tail-shock paradigm produces three sequential analgesic states as the number of shocks increases: an early opioid analgesia (after 2 shocks) that is attenuated by systemic naltrexone, a middle analgesia (after 5-40 shocks) that is unaffected by systemic naltrexone, and a late opioid analgesia (after 80-100 shocks) that is attenuated by systemic naltrexone. In order to determine whether the absence of adrenal hormones would affect any of these analgesias, we tested adrenalectomized (ADX) versus sham-operated control rats 2 weeks post-surgery. Pain threshold was assessed using the tail-flick (TF) test. ADX attenuated both the early (2 shock) and late (80-100 shock) opiate analgesias and failed to reduce the naltrexone-insensitive analgesia after 5-40 shocks. We demonstrated that a loss of adrenomedullary catecholamines does not underlie the ADX-induced attenuation of opioid analgesia since sympathetic blockade using systemic chlorisondamine (6 mg/kg) failed to reduce analgesia at any point in the shock session. It was further shown that stress levels of adrenal hormones are not critical since (a) analgesia was unaffected when animals were tested 48 h after ADX, (b) 2 shocks do not produce a surge in corticosterone (CORT) over and above levels observed in animals restrained and TF tested in preparation for shock, and (c) basal CORT replacement in drinking water fully restored analgesia in ADX rats. These experiments demonstrate that basal CORT, rather than adrenomedullary substances, is critical to the expression of analgesia. The function of CORT here is not linked to a shock-induced surge of the steroid. CORT appears to play a permissive role in the expression of analgesia. Potential effects of the absence of corticosteroids on neurotransmitter biosynthesis important in analgesia production are discussed.

Adrenal Medulla↗
PubMed1989

[Irrigant solutions].

After reviewing the various irrigation solutions, indications and chemical properties are described and stress laid on chloroform and chelating agents. Although these are not used as canal irrigants in the strict sense, their special features suggest that they might be included in this group of substances.

Chemical Phenomena↗
PubMedDate not supplied

[Sports activities and maxillofacial injuries. Current epidemiologic and clinical aspects relating to a series of 379 cases (1982-1998)].

BACKGROUND: The constant improvement in the quality of individual life and growing interest in sporting activities have resulted in an increased use of sport in free time at amateur level. As a result, sports injuries have steadily increased since the late 1980s. The aim of this study was to illustrate our experience in the treatment of injuries in this particular category. METHODS: The series included patients admitted to the Division of Maxillofacial Surgery at Turin University over a 15-year period. A total of 379 maxillofacial fractures caused by sporting activities were recorded out of a total of 2925 cases. The factors examined included: the type of sport, the age and sex of the patient, the cause of the injury, the site of the lesion and the treatment. RESULTS: Sports injuries represent 12.9% of total injuries. The mean age of patients was 32.1 years and the male/female ratio was 5.6:1. A range of 36 sports were examined, but football (43.5%), cycling (23.4%) and skiing (13.9%) represented 80.9%. The injuries observed involved different areas of the face with a prevalence of the orbital/zygomatic complex (47.4%) compared to the mandibular region (42%). The most important forms of treatment and preventive therapy were examined and a comparison was made of their incidence. CONCLUSIONS: The authors conclude by emphasizing the importance of prevention in sports injuries.

Adolescent↗