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At least 199 records · Page 11Linked to original sources
PubMed2003

Spleen volume and blood flow response to repeated breath-hold apneas.

The purpose of this study was 1) to answer whether the reduction in spleen size in breath-hold apnea is an active contraction or a passive collapse secondary to reduced splenic arterial blood flow and 2) to monitor the spleen response to repeated breath-hold apneas. Ten trained apnea divers and 10 intact and 7 splenectomized untrained persons repeated five maximal apneas (A1-A5) with face immersion in cold water, with 2 min interposed between successive attempts. Ultrasonic monitoring of the spleen and noninvasive cardiopulmonary measurements were performed before, between apneas, and at times 0, 10, 20, 40, and 60 min after the last apnea. Blood flows in splenic artery and splenic vein were not significantly affected by breath-hold apnea. The duration of apneas peaked after A3 (143, 127, and 74 s in apnea divers, intact, and splenectomized persons, respectively). A rapid decrease in spleen volume ( approximately 20% in both apnea divers and intact persons) was mainly completed throughout the first apnea. The spleen did not recover in size between apneas and only partly recovered 60 min after A5. The well-known physiological responses to apnea diving, i.e., bradycardia and increased blood pressure, were observed in A1 and remained unchanged throughout the following apneas. These results show rapid, probably active contraction of the spleen in response to breath-hold apnea in humans. Rapid spleen contraction and its slow recovery may contribute to prolongation of successive, briefly repeated apnea attempts.

Adult↗
PubMed2005

Year-round recordings of behavioural and physiological parameters reveal the survival strategy of a poorly insulated diving endotherm during the Arctic winter.

Warm-blooded diving animals wintering in polar regions are expected to show a high degree of morphological adaptation allowing efficient thermal insulation. In stark contrast to other marine mammals and seabirds living at high latitudes, Arctic great cormorants Phalacrocorax carbo have very limited thermal insulation because of their partly permeable plumage. They nonetheless winter in Greenland, where they are exposed to very low air and water temperatures. To understand how poorly insulated diving endotherms survive the Arctic winter, we performed year-round recordings of heart rate, dive depth and abdominal temperature in male great cormorants using miniature data loggers. We also examined the body composition of individuals in the spring. Abdominal temperatures and heart rates of birds resting on land and diving showed substantial variability. However, neither hypothermia nor significantly lower heart rate levels were recorded during the winter months. Thus our data show no indication of general metabolic depression in great cormorants wintering in Greenland. Furthermore, great cormorants did not reduce their daily swimming time during the coldest months of the year to save energy; they continued to forage in sub-zero waters for over an hour every day. As birds spent extended periods in cold water and showed no signs of metabolic depression during the Arctic winter, their theoretical energy requirements were substantial. Using our field data and a published algorithm we estimated the daily food requirement of great cormorants wintering in Greenland to be 1170+/-110 g day(-1). This is twice the estimated food requirement of great cormorants wintering in Europe. Great cormorants survive the Arctic winter but we also show that they come close to starvation during the spring, with body reserves sufficient to fast for less than 3 days. Lack of body fuels was associated with drastically reduced body temperatures and heart rates in April and May. Concurrent, intense feeding activity probably allowed birds to restore body reserves. Our study is the first to record ecophysiological parameters in a polar animal on a year-round basis. It challenges the paradigm that efficient thermal insulation is a prerequisite to the colonization of polar habitats by endotherms.

Acclimatization↗
PubMed1990

Otolaryngic examination of the sport scuba diver.

Diving is a sport presenting unique environmental and physiological hazards to its participants. Despite this, scuba diving is an enjoyable and safe hobby, with an estimated rate of 250,000 new divers certified each year. The ears, nose, and paranasal sinuses are the source of the most common problems in divers. Proper otorhinolaryngic medical examination is vital in the certifying of diving candidates and in routine examinations of active scuba divers. Most authorities agree on major guidelines applicable in ENT examination, although some points are a matter of controversy. Based on the major sources on the subject and our own experience, we have listed disqualifying disorders and relative or temporary contraindications for sport scuba diving. Although there are no regulations specifying medical standards for sport divers in the United States, we have tried to provide guidelines for the general practitioner and ENT specialist engaging in an otolaryngic medical examination of a sport scuba diver.

Clinical Protocols↗
PubMed1983

["Typical" and "less typical" sports injuries in the field of neurology].

In times of increasing "sparetime pathology" sequels of sports are getting a new meaning in medicine. Surgeons are mainly involved in this issue but it also contacts neurologists. We differentiate between direct sequels of sports and concomitant incidents of sports. Besides the typical head injuries we saw a number of atypical traumatic damages such as a hit by a golf ball, fall on the buttocks and the header in football. Discprotrusions are mainly understood as concomitant incidents at sports because in most cases one has to consider preexisting disc lesions. Though there are typical motions in sports which rather lead to discprotrusions such as strong torsions of the body in football, serving in tennis, heavy lifting in wrestling or an unexpected fall into a hollow in skiing. In cerebrovascular events, sports is usually only one additive etiological component. Nevertheless the lack of adequate acclimatisation and the brisk beginning of stressing sports in high mountain areas (which is enabled through modern technic) can contribute a great deal to decompensation of cerebrovascular disorders. In this respect doping can have a serious influence since protecting physiological mechanisms are eliminated. Diving accidents are able to give rise to spinal, cerebral and cerebellar gasembolisation. Warning early symptoms of great value are TIA, vertigo and fits. Sport practice can figure as an unspecific test situation in order to provoke these events. Diagnostic investigation of the cardiovascular system and the CNS has to be performed in those cases. Particular regard should be paid to expert situations which tend to distort the clinical pictures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗