Development of the subfornical organ and area postrema of the male albino mouse. Karyometric effect of neonatal and prepuberal castration

We have studied the karyometric development of the nuclei of the ependymal cells and neurons of the subfornical organ and the area postrema in the male albino mouse from the 5th to the 190th postnatal day. We have found similar patterns of development in both although the area postrema showed more significant postnatal oscillations than those of the subfornical organ, suggesting a more intimate chronological relationship to gonadal development. We have furthermore analyzed the development in two experimental groups: in the one animals were castrated at birth, in the other, castration was made on the 20th postnatal day. We have found that neonatal castration produced a significant decrease of nuclear sizes; this was more evident in the subfornical organ than in the area postrema in earlier stages of development while the response was similar in both at peripuberal ages. The response to prepuberal castration was similar in both organs.     

Ultrastructure of the epithelial cells of the ventral prostate from the hopping mouse Notomys alexis

The large ventral prostate of the hopping mouse has abundant secretory units whose epithelial cells vary in height and which often have nuclei in the apical region of the cell. TEM observations indicated two epithelial cell types in which some unusual features occurred. Type A cells had granular endoplasmetic reticulum (GER) whose membranes often formed intracytoplasmic confronting cisternae. Type B cells had more fragmented and vesiculated GER with sparse ribosomes and less frequently also intracytoplasmic confronting confronting cisternae. In the latter cells, two types of granules were found, one of which was derived from the Golgi and the other possibly directly from the GER. Type A cells only had one type of granule present. A highly convoluted membrane was also found at the basal region in many of the cells. The significance of these unusual ultrastructural features has yet to be ascertained.     

Establishment and yield of three ryegrasses following aldicarb use, and changes in abundance of plant parasitic nematodes

Pure swards of Lolium multiflorum, L. multiflorum var. westerwoldicum and L. perenne sown in August had greater yields than autumn on areas treated with either 5 or 10 kg a.i./ha aldicarb than on untreated areas. Total annual dry matter yields increased by larger amounts where the greater rate of aldicarb was applied; throughout the trial, L. perenne was usually less affected by treatment than the other two grasses. Plant-parasitic nematodes were more numerous on untreated than treated plots and were fewest in areas receiving the larger application (except in the second harvest year). Numbers of Tylenchorhynchus and Helicotylenchus were affected most by treatments; abundance of Paratylenchus and Criconemella were little altered. Stem-boring Diptera invaded tillers of all three grasses but infection was least in L. perenne. Invasion occurred only on untreated plots in the establishment year and some yield benefit probably resulted from their control. In subsequent years invasion was similar on treated and untreated areas. Effects on other, non-target organisms were not assessed. Ectoparasitic nematodes multiplied more in L. multiflorum plots than in others during the first full-harvest year. The next year numbers of Paratylenchus only were greater in plots of L. perenne than in other plots. Sward persistence of L. multiflorum var. westerwoldicum was better on treated than untreated areas. It was concluded a) that aldicarb use greatly decreased nematode numbers and yields from treated areas were larger than from those untreated; b) that sward persistence was similarly improved following aldicarb use and c) that ryegrasses differed in their suitability as hosts to ectoparasitic nematodes.     

An animal model for tumors of the large intestine]

Dimethylhydrazine (DMH) and its derivatives induced in many animal species tumors of the large intestine with a great specificity and reproductibility. Oour personal observations using rats BD IX injected weekly with DMH are summarized in this presentation. The induced tumors appear as invaded tumors already at the microscopic stade. Their growth is best described by a Gompertz function. The number of induced tumors increases with time as a non linear function. This model is very useful for the study of the biology of human tumors with a low development.     

Purification of a hydrophobic surfactant peptide using high-performance liquid chromatography

A 4- to 6-kDa hydrophobic peptide (SP4-6) was purified from human pulmonary surfactant. Sep Pak Florisil cartridges removed most of the lipids and the 18-kDa peptide. Analytical wide-pore reversed-phase HPLC column separated a single peptide that contained no detectable lipids (less than 1 nmol/2.5 micrograms protein). N-terminal analysis indicated that this peptide was pure, but the N-terminal amino acid was blocked. The peptide was capable of restoring the in vitro surface properties of synthetic phospholipids, which is characteristic of native lung surfactant.     

CHOLINE ACETYLTRANSFERASE, ACETYLCHOLINESTERASE AND AROMATIC l-AMINO ACID DECARBOXYLASE IN SINGLE IDENTIFIED NERVE CELL BODIES FROM SNAIL HELIX ASPERSA

—The distribution of choline acetyltransferase, aromatic l -amino acid decarboxylase and acetylcholinesterase in the nervous system of Helix aspersa has been studied using homogenates of whole ganglia, microdissection from freeze-dried sections and dissection of single neurons from fresh tissue. Choline acetyltransferase was found in both the cell body and neuropil layers of all the Helix ganglia. The enzyme was not specifically localized to any ganglion or region of ganglion. Between 10 and 30 per cent of the isolated single cell bodies contained the enzyme. The enzymic activity corresponded to 50–200 mmol ACh/1 cell bodies/h. Choline acetyltransferase is probably a specific marker for cholinergic cells in this species. Aromatic l -amino acid decarboxylase was more selectivity localized and its distribution corresponded well with that of monoamine containing cells as visualized by the fluorescence histochemical technique. A large proportion of cell bodies were localized in the boundary between the visceral and right parietal ganglia and in the pedal ganglion. The other ganglia contained few such cells. The activity of aromatic l -amino acid decarboxylase corresponded 10–50 mmol dopamine/1 cell bodies/h. A method was developed to measure the enzyme activity towards 5-hydroxytryptophan and DOPA in single cells simultaneously. The ratio between the activity towards both substrates did not vary significantly for the different cells. The enzyme is probably a specific marker for monoamine cells, but cannot be used to differentiate between the different monoamine cells. Acetylcholinesterase was uniformly distributed in the ganglia and was probably present in all nerve cells.