Crypt architecture of tonsilla lingualis in the monkey,Macaca fascicularis

Summary Crypts of the lingual tonsil were investigated in 10 male and female Macaca fascicularis by use of correlated light and scanning-electron microscopy. Counting of crypt openings provided an estimate of the total number of respective crypto-lymphatic units, which were found to range from 20 to 39. Crypt openings appeared in three distinct morphological varieties, i.e. circular, oval or slit-like. Tonsillar units existed individually or were arranged in a rosary fashion below a slit-like mucosal fold serving as a common exit. Although the crypt epithelium was generally non-keratinized, individual cells showing a surface pattern similar to that of the keratinized cells could be encountered. The crypt epithelium was frequently fragmented and showed heavy mononuclear cell infiltration and surface discontinuities, with lymphoid cells coming in contact with luminal contents. The crypt lumen either appeared as a simple epithelial invagination or existed as a complex, cavernous pouch with many blind-ending diverticula. The lumen contained a mixture of exfoliated epithelial cells, leucocytes and bacteria. The secretory ducts of the posterior lingual glands opened occasionally at various levels into the crypt lumina or independently to the exterior.     

Morphological investigations on follicular atresia in canine ovaries

Summary Morphologically, canine ovaries show two types of regression pattern in secondary follicles. In type A necrotic changes of the oocytes and the zona pellucida dominate, whereas in type B degeneration, necrobiosis and necrosis of the granulosa prevail. The atretic course of type B regression results in a pseudoantrum and leads, by pseudogrowth, to a structure imitating tertiary follicles. In both type A and type B regression, four consecutive stages of atresia are distinguished by light- and electron microscopy.True tertiary follicles display only one regression pattern which resembles type B of secondary follicles. Early, advanced, late, and terminal stages of atresia are again described.     

Adenine nucleotide pool size,adenine nucleotide translocase activity,and respiratory activity in newborn rabbit liver mitochondria

The adenine nucleotide content (ATP+ADP+AMP) of newborn rabbit liver mitochondria was 6.0±0.5 nmol/mg mitochondrial protein at birth, increased rapidly to 14.5±1.7 nmol/mg protein by 2 h postnatal, peaked at 6 h, then decreased gradually to 7.8±0.6 nmol/mg protein by 4 days postnatal. There was a strong positive correlation (r=0.82) between the total adenine nucleotide pool size and adenine nucleotide translocase activity in these mitochondria. In contrast, glutamate + malate-supported State 3 respiratory rates remained constant from birth through the first week of life. State 4 rates also remained constant, as did the respiratory control index and uncoupled respiratory rates. The following conclusions are suggested: (1) The maximum rate of translocase activity is limited by the intramitochondrial adenine nucleotide pool size. (2) In newborn rabbit liver mitochondria, the State 3 respiratory rate is not limited by either the adenine pool size or the maximum capacity for translocase-mediated adenine exchange. (3) In contrast to rat, rabbit liver mitochondria are fully functional at birth with regard to respiratory rates and oxidative phosphorylation. (4) The rapid postnatal accumulation of adenine nucleotides by liver mitochondria, now documented in two species, may be a general characteristic of normal metabolic adjustment in neonatal mammals.     

Localization of lysosomal antigens in activated T-lymphocytes

Summary The lysosomal compartment has been examined in activated T-lymphocytes by immunogold electron microscopy and subcellular fractionation. Immunoprecipitation and sodium dodecyl sulphate-polyacrylamide gel, electrophoresis (SDS-PAGE) of radiolabelled extracts of the T-cells showed that they contained three antigens which are fundamental to normal lysosomal function: a representative lysosomal enzyme -glucuronidase, a lysosomal associated membrane protein (LAMP-1), and the cation-independent mannose 6-phosphate lysosomal enzyme targeting receptor (MPR). Immunogold labelling showed that -glucuronidase was present in the rough endoplasmic reticulum, the Golgi complex and Golgi-associated vesicles. The enzyme was also found to accumulate in distinct, non-Golgi organelles in which LAMP-1 was co-localized, probably lysosomes. LAMP-1 was also found in tubular elements of the golgi and in a complex of vesicles clustered near the nucleus where MPR was also present at high density.Fractionation of homogenates from lymphocytes on Percoll gradients revealed that -glucuronidase was distributed throughout the low density region containing rough endoplasmic reticulum, Golgi and plasma membrane components, and the high density region which contained only lysosomal activity. Multiple immunogold electron microscopy of the latter fraction showed the presence of homogenous vesicles which had large amounts of -glucuronidase within the lumen, LAMP-1 at the periphery and no MPR. These vesicles were probably mature lysosomes, arising from pre-lysosomal organelles enriched for LAMP-1 and MPR.     

Alterations in Cortical [3H]Kainate and α-[3H]Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic Acid Binding in a Spontaneous Canine Model of Chronic Hepatic Encephalopathy

Excitatory amino acid receptor binding parameters were investigated in a spontaneous dog model of chronic hepatic encephalopathy. L-[3H]Glutamate, (+)-[3H]-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-im ine maleate ([3H]MK-801), [3H]kainate, and alpha-[3H]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ([3H]AMPA) binding experiments were performed using crude cerebrocortical synaptosomal membrane preparations from dogs with congenital portosystemic encephalopathy (PSE) and control dogs. There was no change in the affinity or density of L-[3H]-glutamate or [3H]MK-801 binding sites in dogs with congenital PSE compared with control dogs. However, in the PSE dogs there was a significant reduction in the density of [3H]kainate binding sites compared with control dogs and abolition of the low-affinity [3H]AMPA binding site. The relative binding capacity of PSE synaptosomal membranes for [3H]kainate and [3H]AMPA was expressed as the ratio Bmax/KD. There was a significant inverse correlation between the Bmax/KD ratio for [3H]AMPA binding and the worst grade of encephalopathy experienced by each dog. These results suggest that there is a significant perturbation of cerebrocortical non-N-methyl-D-aspartate receptor binding in dogs with congenital PSE which may have relevance to the pathogenesis of hepatic encephalopathy.     

Stream flow and predation effects on the spatial dynamics of benthic invertebrates

Field experiments were carried out to determine the influence of predation and prey movements on the accumulation of prey in enclosures. Experimental enclosures permitted exchange of prey with the benthos, but not of the large, predatory larvae of the caddisfly, Plectrocnemia conspersa (Curtis). Unseasonally heavy rainfalls during the experiment resulted in high flows and enabled us to examine the effects of a major, abiotic disturbance on invertebrate spatial dynamics. Prey colonization rates of cages without predators were determined in nine 24 h periods. Colonization rates increased exponentially with flow and were species-specific, depending on dispersal behaviour. Prey accumulation and predator impacts were measured in cages, with and without P. conspersa larvae, placed in the stream for 1, 2 or 3 weeks. Prey densities in cages increased with exposure time, but increases were not gradual and depended on flow regime. Flow was reduced within cages and they accumulated large numbers of invertebrates during high discharge. Analogous, naturally occurring refugia in the stream channel could be important for the recovery of lotic communities after major disturbances. Overall, prey densities were lowest in cages with predators. For fast colonizers, predation effects were detectable early in the experiment, but quickly obscured thereafter by continuous exchange of prey. For slow colonists, predation effects were detectable later, but persisted longer. Consumption rates for P. conspersa varied with prey density and flow regime. We suggest that the spatial dynamics of benthic invertebrates, especially as they are influenced by stochastic events, are important in understanding and detecting predation effects in stream communities.     

Effect of cold environment on skeletal muscle mitochondria in growing rats

Summary Growing rats (4 weeks old) were kept for 3 weeks at 11° C and 24° C respectively. The cold-adapted animals showed a significantly higher oxygen consumption (64%). Volume density of subsarcolemmal and interfibrillar mitochondria as well as volume density of fat droplets were estimated in M. soleus and the diaphragm of both groups. In cold-adapted animals, the total volume of mitochondria was significantly increased by 24% in diaphragm and 37% in M. soleus. The volume of subsarcolemmal mitochondria was almost doubled in each muscle, but the volume of interfibrillar mitochondria did not change significantly. The surface of the inner mitochondrial membranes per unit volume of mitochondrion in M. soleus was significantly increased both in interfibrillar and subsarcolemmal mitochondria, whereas the surface of the outer mitochondrial membranes per unit volume of mitochondrion was increased only in the subsarcolemmal mitochondria. The volume of fat droplets in the diaphragm and M. soleus of cold adapted animals increased significantly by 62% and 150% respectively.