Genetic Influences on Circadian Rhythms in Mammals

Author(s):  
Joseph Takahashi ◽  
Sharon Low-Zeddies
Author(s):  
Shirley Siew ◽  
Susan C. James

Testicular maldescent is the most common endocrine gland abnormality, as 2.7% of mature neonates are cryptorchid. The significant complications are that there is a disturbance of normal maturation which results in diminished fertility and there is an increase in the malignant potential which is 35 times greater in the undescended than the descended testis. It is considered that genetic influences may be of etiological importance and recurrence has been described in some families. It is of interest, that the case reported here has 2 siblings who have also presented with cryptorchidism and malignant tumors.The propositus is 14 years old. He is well developed (described by some as obese) and shows normal secondary male characteristics except for an immature scrotum. Laparotomy showed both testes to be intraabdominal. A hard nodule (0.5cm) was palpated on the medial aspect of the left testis. Frozen section showed the presence of seminoma and bilateral orchiectomy was performed.


2006 ◽  
Vol 19 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Myriam Juda ◽  
Mirjam Münch ◽  
Anna Wirz-Justice ◽  
Martha Merrow ◽  
Till Roenneberg

Abstract: Among many other changes, older age is characterized by advanced sleep-wake cycles, changes in the amplitude of various circadian rhythms, as well as reduced entrainment to zeitgebers. These features reveal themselves through early morning awakenings, sleep difficulties at night, and a re-emergence of daytime napping. This review summarizes the observations concerning the biological clock and sleep in the elderly and discusses the documented and theoretical considerations behind these age-related behavioral changes, especially with respect to circadian biology.


1982 ◽  
Vol 27 (12) ◽  
pp. 931-932
Author(s):  
Gerald S. Wasserman
Keyword(s):  

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