Organohalogen concentrations and a gross and histologic ...

Figure 2
Renal lesions in a 19-year-old
female polar bear sampled in January
2000 (same as Fig. 1). Top: obvious
hyalinisation of tubular basement
membranes (PAS, 20x). Bar:
25 µm. Arrows indicate hyalinisation
of tubular basement membranes
and macrophages containing
PAS-positive debris within
atrophic tubules. Note the large
amounts of fibrous tissue around
the hyalinised basement membranes.
Bottom: total glomerular
sclerosis (left) (PAS, 40x). Note the
large amount of fibrous tissue
around the glomerulus (arrow). Bar:
50 µm.
164
Tubular lesions
Tubular lesions were PAS-positive hyalinisation of the tubular basement
membrane with tubular atrophy and fibrosis (Fig. 2). The lesions were in
severe cases accompanied by total glomerular hyalinisation (sclerosis) (Fig.
2). Furthermore, hyperplastic cell-proliferation, within the basement membrane
of a distal convoluted tubule, was found in a 7-year-old male polar
bear (Fig. 3). The cells were large and pale with a polygonal and monomorphic
appearance prominating into the luminal area. Finally, tubular
intracellular protein droplets and pigments – localised basally and apically –
was found in the entire nephron of all individuals (Fig 3). The pigments
were tested negative for both lipofuscin and haemosiderin and could therefore
be bile pigments, haemoglobin, melanin or byproducts from the metabolism
of plant material during summer (Lyon et al., 1991).