Origin of the v. portae and variability of its tributaries in laboratory animals. II. The guinea pig (Cavia aperea f. porcellus)

The authors investigated the origin of the v. portae and variability of its main tributaries in 30 adult guinea pigs (Cavia aperea f. porcellus). The venous bed was visualized by means of blue-dyed latex. The v. portae was formed the most frequently - in 17 cases (56.7%) - by the confluence of three veins - the v. mesenterica cranialis, the v. lienalis and the v. gastroepiploica dextra; less often it was formed from four or five tributaries and in one case only it was formed by union of the v. mesenterica cranialis and the v. lienalis. The v. gastrica sinistra was a tributary of the v. lienalis in 24 cases (80.0%). It arose on the ventral and the dorsal surface of the stomach, in the region adjacent to the curvatura minor ventriculi. In 21 cases (70.0%) it was joined by an independent v. cardiaca. The v. lienalis originated in the hilus lienis, usually as a result of the union of two venous trunks. Inter-organ anastomoses were found in 26 cases (86.7%); in 10 cases (33.3%) they occurred simultaneously between the spleen and the stomach and between the spleen and the pancreas, while in 16 cases (53.3%) they connected the superior pole of the spleen with the stomach. An independent v. gastroepiploica dextra was present in 19 cases (63.3%) as a tributary of the v. portae. In 22 cases it was joined by the v. pylorica. A v. pancreaticoduodenalis cranialis was present in 27 cases (90.0%). In 18 cases (60.0%) it united with the v. gastroepiploica dextra to form a common trunk, the v. gastroduodenalis, which joined the v. portae; in two cases (6.7%) it was an independent tributary of the v. portae. In six cases it was connected with the v. lienalis and in three cases (10.0%) it was replaced by a few vv. pancreaticae emptying into the v. lienalis. A typical v. pancreaticoduodenalis caudalis, as a tributary of the a. mesenterica cranialis, was found in 19 cases (63.3%). In two cases, together with the v. pancreaticoduodenalis cranialis, it formed a single trunk (the v. pancreaticoduodenalis communis). A comparison of the v. portae and its tributaries in the guinea pig and the cat has so far not brought to light any significant morphological differences relative to their different zoological classification and their different modes of life.     

Origin of the v. portae and variability of its tributaries in laboratory animals. III. The laboratory rat (Rattus norvegicus var. alba)

The authors studied the origin of the v. portae and the variability of its tributaries in 30 adult laboratory rats (Rattus norvegicus v. alba) after injecting blue-dyed latex into the venous bed. In 21 cases (70.0%) the v. portae was formed from three tributaries. In 18 of these cases (60.0%) they were the v. mesenterica cranialis, v. lienalis and v. pancreaticoduodenalis cranialis. In eight cases the v. portae was formed from four or five tributaries and in only one case was it formed from two--the v. mesenterica cranialis and v. lienalis. In 21 cases (70.0%) the v. gastrica sinistra was a tributary of the v. lienalis. It collected blood from the anterior and posterior surface of the stomach and sometimes originated as far away as the curvatura major ventriculi. A v. cardiaca was present in all 30 cases (100%). As a rule (in 28 cases, i.e. 93.3%), it was a tributary of the v. gastrica sinistra. There was likewise a v. pylorica in every case; most frequently this united with the v. pancreaticoduodenalis cranialis, but was also connected with other veins in the vicinity. A v. pancreaticoduodenalis cranialis was always present. In 22 cases (73.3%) it was an independent tributary of the v. portae. In 11 cases (36.7%), there were no vv. gastroepiploicae or equivalent vessels and blood from the stomach was drained mainly by the v. gastrica sinistra. A v. gastroepiploica dextra was present in 11 cases (36.7%), mostly as a tributary of the v. lienalis; in two cases (6.7%) there was a v. gastroepiploica sinistra and in six cases (20%) the place of these veins was taken by vv. gastricae as tributaries of the v. lienalis. In 21 cases (70.0%) the v. lienalis was joined by the v. gastrica sinistra. In 22 cases (73.3%) inter-organ anastomoses between the spleen, stomach and pancreas were found. A v. pancreaticoduodenalis caudalis was always present and in 20 cases (66.7%) it was an independent tributary of the v. mesenterica cranialis. A comparison of the origin of the v. portae and the organization and variability of its tributaries in the rat, cat and guinea pig shows that, in agreement with their position in the zoological system and their mode of life, there was greater similarity between the rat and the guinea pig as regards practically all the veins examined.     

The rex mutants of the domestic cat

New data demonstrate that the Cornish and German rox mutants are either identical or are phenotypically closely similar alleles at the same locus. The Devon rex is definitely independent of Cornish and it seems probable that the Oregon rex is independent of Cornish and Devon.     

The velocity of the River Tweed and its tributaries

SUMMARY. Velocity measurements at fourteen hydrometric stations in the Tweed basin are described and analysed. Along-stream velocity variations are examined and it is shown that at most flow levels the highest velocities occur at the lower, flatter end of the river system. Estimates of the frequency with which velocities of different magnitudes can be expected to occur in the river are also presented. These indicate that the velocity at most stations rarely exceeds 3.0 m s⁻¹ and for most of the time it lies between 0.25 and 1.0 m s⁻¹. The inadequacy of subjective velocity assessment is stressed and a method suggested whereby data similar to those presented could readily be produced for almost any cross-section along a river like the Tweed.     

Veins of the large intestine, stomach and pancreas of the domestic cat and their variability

Most frequently - in 19 cases (63.3%) - the v. colica media was a tributary of a trunk, formed together with the v. mesenterica caudalis, which emptied into the v. mesenterica cranialis. In two cases (6.7%) it emptied independently into the v. mesenterica cranialis. In 25 cases (83.3%) the v. mesenterica caudalis arose from the rectum and, at colon ascendens level, acquired one or more vv. colicae sinistrae. In six cases (19.8%) the v. colica dextra opened into the v. ileocolica and in eight cases (26.7%) it was the initial tributary of an independent v. ileocolica which joined the v. mesenterica cranialis directly. The drainage of venous blood from the stomach is organized as follows: the fundus region is connected to the v. lienalis by means of inter-organ anastomoses. The curvatura minor is drained by means of the v. gastrica sinistra. Venous blood from the region of the curvatura major ventriculi flows partly into the v. lienalis (by way of the vv. gastroepiploicae or small veins) and partly into the v. gastrica sinistra. Drainage of venous blood from the pancreas: a v. pancreaticoduodenalis cranialis was present in 16 cases (53.3%) and a typical v. pancreaticoduodenalis caudalis was found in 12 cases (40.0%). Simultaneous formation of both vv. pancreaticoduodenalis, with a possible incidence of small venous efferents to the v. lienalis, was observed in only nine cases (30.0%). In 21 cases (70%), blood from the region of the flexura duodenojejunalis was drained by the last v. jejunalis; in other cases it drained into the vv. pancreaticoduodenales.(ABSTRACT TRUNCATED AT 250 WORDS)     

The impact and potential etiology of teratospermia in the domestic cat and its wild relatives

Teratospermia (production of >60% morphologically abnormal sperm/ejaculate) is relatively common among various species in the family Felidae, which is comprised of 37 species. Over two decades of research in this area have produced a significant understanding of the phenotypic expression, its impacts on sperm function and etiology. There is good evidence suggesting that a reduction in genetic diversity contributes to this phenomenon. Results to date demonstrate that spermatozoa from teratospermic donors are compromised in the ability to undergo capacitation and the acrosome reaction, penetrate the zona-pellucida, fertilize conspecific oocytes and survive cryopreservation. Recent studies also reveal abnormalities in chromatin integrity in sperm from teratospermic donors, which, interestingly, fails to impact fertilization or embryo development after intracytoplasmic sperm injection. Through planned inbreeding studies, we now have established that teratospermic cats also produce more spermatozoa by virtue of more sperm producing tissue, more germ cells per Sertoli cell and reduced germ cell loss during spermatogenesis. Overall, it now is clear that gain in sperm quantity is achieved at the expense of sperm quality, suggesting an extensive disruption of normal testicular function in teratospermic donors. Preliminary studies on testicular gene expression in teratospermic cats have also revealed abnormal expression patterns. These findings have markedly increased our understanding of testis biology in the teratospermic donor and reaffirm the value of cats, including wild species, as models for studying novel regulatory mechanisms controlling spermatogenesis and spermiogenesis.     

Nutrients in the Changjiang and its tributaries

Dissolved and particulate, organic and inorganic N, P and Si weremeasured in the main stream and 15 major tributaries of the Changjiang (YangtzeRiver) in April–May 1997. The nutrient concentrations are related towaterdischarge, suspended particulate matter, anthropogenic activities etc. Thenutrient levels were quite low in the upper reaches, and significantlyincreasedin the main stream in a region of 2000–3000 km inland from the rivermouth. The northern tributaries contribute more nutrients to the Changjiangthanthe southern tributaries. Based on atomic ratios of N, P and Si, the limitingnutrient in the Changjiang drainage basin was P. The nutrient yields in theChangjiang and its major tributaries indicated high rates of transport ofnutrients within the watersheds. Concentrations of nitrate in the Changjianghave increased, but there have been no systematic trends for phosphate andsilicic acid since 1980. The DIN/P ratios and DIN/Si ratios increased. TheDIN/Pand DIN/Si ratios may be expected to continue to increase after construction ofthe Three Gorges Dam, which will exercise a great deal ofinfluence on theecological environment of the Changjiang estuary and its adjacent sea.     

Phytobenthos of the River Tees and its tributaries

SUMMARY. A standard method is given for describing plant communities in fast-flowing streams and rivers. This involves the selection of a representative 10-m length of stream (termed a reach) which can be re-located exactly. Various estimates of the relative areas covered by different physiognomic forms and the relative proportions of species present are then combined to give a 'semi-quantitative' account, which can be compared with data collected at other sites or times. The method has been applied to six sites on the River Tees system. A site below Cow Green reservoir with markedly regulated flows, differs from the others in various ways. Bryophytes show a greater cover here than elsewhere throughout the year and a conspicuous cover of Phormidium occurs in autumn. Filamentous green algae of many different species are abundant at this site in late summer and early autumn. At the most downstream site where such seasonal growths also occur, a single species, Cladophora glomerata , is dominant. Conspicuous spring diatom 'bursts' occurred at the two upstream sites and a month later at the two downstream sites.     

Gamete cryopreservation in the domestic cat

Cryopreservation of gametes is an important tool for the improvement of assisted reproductive technologies. In-depth studies of spermatozoon and oocyte characteristics are required in order to define efficient protocols for the maintenance of viability, including fertilizing and developmental ability, of gametes after thawing. In the domestic cat, semen cryopreservation techniques still produce variable results, the cryopreservation of oocytes is at an experimental level and there have been only a few attempts at cryopreserving gonadal tissue. However, each procedure has generated promising results and has important implications, both for improving reproductive performance of valuable breeds of domestic cats and for conservation of biodiversity in endangered felids by reclamation of valuable male and female germplasm.     

Sperm maturation in the domestic cat

The epididymis is essential for sperm development and maturation, and, subsequently, the ability of spermatozoa to penetrate and fertilize the female gamete. Functional differences in segments of the long tubule are reflected by histological differences among epididymal regions. The feline epididymis can be divided into six different regions according to their histological differences. A marked increase in sperm concentration occurs between regions 2 and 3, indicating resorption of fluid in region 2, a concept supported by the histological characteristics of the epithelium. At the transition between regions 4 and 5, located between the caput and corpus epididymides, histological characteristics change from being that of a maturation function to being typical of a storage function. Migration of the cytoplasmic droplet and induction of motility occur in this same region. Proteins are secreted from epithelial cells in the feline epididymis by merocrine and apocrine secretion, although the functions of different feline epididymal proteins have not been determined. Hypotaurine, taurine and, probably, alkaline phosphatase are produced by the feline epididymis. During epididymal transit the percentage of immature, unviable and morphologically abnormal spermatozoa decreases, indicating the existence of a mechanism that removes abnormal spermatozoa. In contrast, the percentage of spermatozoa with abnormal tails increases slightly during epididymal transit. Most of the distal droplets present on spermatozoa in the cauda epididymis are lost at or after ejaculation. Additional knowledge of the feline epididymis should be beneficial for developing sperm preservation protocols and advance the prospects for effective male contraceptive methods.     

Observations on variability in LH release and fertility during oestrus in the domestic cat (Felis catus)

Hormonal changes, behaviour, ovulation and fertility were examined in response to coitus at two different times during oestrus in the female domestic cat housed in conditions of natural light (N = 13). On Day 2 or Day 4/5 of oestrus females were allowed 1 copulation in 15 min (single matings) or 2-3 copulations in 30 min (multiple matings). Plasma LH, oestradiol-17 beta and progesterone concentrations during the 24-h period after coitus were measured by radioimmunoassay; ovulation was assumed to have occurred if progesterone values were elevated 7-30 days after coitus. With the exception of 2 out of 3 animals receiving single matings on Day 2 of oestrus, all animals showed subsequent elevated progesterone values. Females receiving multiple matings had significantly greater releases of LH as measured by the area under the curve than those receiving single matings. There was significantly greater variability in the LH response of queens on Day 2 of oestrus compared to those on Day 4/5 for peak values and area under the curve; the only failure in release of LH was in queens on Day 2. Oestradiol levels did not differ significantly between Day 2 and Day 4/5 of oestrus. Progesterone values remained less than 1 ng/ml for 24 h after coitus. Both LH peak values and area under the curve were significantly greater for animals that became pregnant. There were also significant differences in coital behaviour between queens on Day 2 and those on Day 4/5 of oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aquatic insects of the Neman River and its tributaries

The aquatic insects of the Neman River and its tributaries were studied. 178 species belonging to 9 orders were found: Collembola—2 species, Ephemeroptera—33, Odonata—16, Plecoptera—10, Heteroptera—20, Coleoptera—39, Megaloptera—2, Trichoptera—54, and Lepidoptera—2 species. Two species of aquatic insects new for the Belarusian fauna were found, Pomatinus substriatus (Ph. Müller, 1806) (Coleoptera) and Brachycercus europaeus Kluge, 1991 (Ephemeroptera).     

Tabby pattern alleles of the domestic cat

The status of genetic variation of tabby pattern in the domestic cat is reviewed. Three alleles of the tabby locus (T) have been identified, namely, Abyssinian (Ta), striped (T), and blotched (tb). Additional data are presented for the assortment of these alleles. The Abyssinian is incompletely dominant to the striped and blotched alleles, whereas striped is completely dominant to the blotched.     

Topography of horizontal cells in the retina of the domestic cat.

Neurofibrillar methods stain a class of horizontal cells in the cat retina which are shown to be identical with the A-type horizontal cell of Golgi-staining. Thus all of the A-type cells of a single retina can be observed. On this basis the changes in density and dendritic field size of A-type horizontal cells with respect to retinal eccentricity were measured. The decrease in density from centre to periphery is balanced by a corresponding increase in size of the dendritic field. Consequently each retinal point--independent of retinal position--is covered by the dendritic fields of three of four A-type horizontal cells. The nuclei and nucleoli of B-type horizontal cells could also be recognized in neurofibrillar-stained material and thus their distribution was determined. The density ratio B-type: A-type is 2.8 +/- 0.4 and does not vary much from the centre to the periphery of the retina. Each retinal point is also covered by four B-type horizontal cells. Thus a single cone can contact a maximum of eight horizontal cells. The rate of density decrease from centre to periphery is closely similar in cones and horizontal cells but greater in ganglion cells.