In contrast, proteoglycan aggregates in cartilage, seen on electron microscopy as granulelike structures, were clearly smaller in the mutant mice than in the wild-type mice . Immunofluorescence studies with the use of an antibody directed against the polypeptide core of perlecan showed that mutant chondrocytes got an abnormal accumulation of this protein intracellularly , where it colocalized with the endoplasmic reticulum marker calreticulin partially. Perlecan, that is a prominent element of basement membranes, can be secreted by dermal fibroblasts, and fibroblasts from mutant mice retained perlecan intracellularly .Swimmers perform alternate breathing which is normally breathing every third stroke. This enables them to breathe on alternate sides without going for a breath with every stroke. At the start, their body demands even more oxygen, but will figure out how to adjust to the reduction in oxygen. In period, the body becomes better in processing the limited air flow. Runners who swim often have excellent breathing efficiency. Breathing rhythms Sometimes, in long races a runner may shed focus and is trashed of his breathing rhythm.