Biomedical subjects

R A Hess

Publications and source records attributed to R A Hess.

At least 73 records · Page 4Linked to original sources

PubMed1990

Quantitative and qualitative characteristics of the stages and transitions in the cycle of the rat seminiferous epithelium: light microscopic observations of perfusion-fixed and plastic-embedded testes.

The stages of the cycle in the rat seminiferous epithelium are illustrated for testes fixed by vascular perfusion and embedded in plastic resins. Improved cellular resolution in plastic sections permitted a clearer demarcation of the stages than in paraffin. Quantitative data are presented to support the recognition of stages, particularly those in transition. Stages IV, V, VII, XI, and XII had the highest frequencies of transitional characteristics. Stage IV was redefined to be more consistent with the occurrence of a high percentage of mitotic figures and to clarify transitions in this stage. Although the resolution of cellular detail was greatly improved with the use of plastics, the thinner sections contained fewer identifying features together within a single tubule cross section and sometimes major characteristics were absent. Therefore, additional characteristics were used for stage classification, such as nuclear diameter and the presence or absence of mitotic figures. A binary decision key is provided to improve consistency among laboratories in the identification of the stages in plastic-embedded testes.

Acrosome↗

PubMed1988

Treatment of experimental autoimmune uveitis in the rat with systemic succinylacetone.

The effects of succinylacetone (SA) on the development of S-antigen-induced experimental autoimmune uveitis (EAU) in the rat were studied. SA totally suppressed EAU at Day 14 when animals were treated with a constant infusion of 1.80 mg/hr by an osmotic minipump. Three intervals of treatment with this dose rate were used (Day 0-7, Day 7-14, or Day 0-14) and, regardless of dosage interval, suppression of the disease was complete. There was a significant inhibition of S-antigen-induced lymphocyte proliferative responses in cells from popliteal lymph nodes (P less than 0.009) as well as a significant decrease of S-antigen antibody production. Animals treated with SA at a rate of 0.90 or 0.45 mg/hr developed EAU in a dose-related fashion. Animals treated with 1.8 mg/hr from Day 7-14 but killed at Day 30 had 100% breakthrough of the disease. Succinylacetone inhibits the expression of EAU and significantly suppresses the immune response to S-antigen. However, once therapy is discontinued the high incidence of breakthrough suggests a reversible noncytotoxic mechanism of immune modulation.

Animals↗

PubMed1987

Immunosuppression by succinylacetone. II. Prevention of graft-vs-host disease.

Succinylacetone is a seven-carbon organic ketoacid that we have previously shown to inhibit tumor allograft rejection as well as the primary antibody response to sheep erythrocytes in rats. Because it appeared to be such a potent immunosuppressive agent in our initial studies, we evaluated succinylacetone for its ability to block graft-vs-host disease (GVHD) in adult F1 rats injected with parental strain spleen cells. Untreated ACE X Lewis F1 rats given Lewis strain spleen cells died of GVHD, with a mean survival of 24 days. By contrast, 62% of F1 rats in the group treated with succinylacetone survived, and the deaths that occurred in this group occurred significantly later. To confirm this observation and determine whether succinylacetone would interfere with bone marrow engraftment, lethally irradiated adult Wistar-Furth rats were reconstituted with syngeneic or totally allogeneic Fisher 344 lymphohemopoietic cells consisting of equal numbers of bone marrow and spleen cells. All animals given allogeneic cells without additional immunosuppressive treatment developed severe GVHD and died by day 42. By contrast 92% of the allogeneic cell recipients that had been treated with succinylacetone were long term survivors. Cytotoxicity typing of peripheral lymphocytes demonstrated greater than 90% donor-type lymphocytes persisting in the succinylacetone-treated recipients as long as 255 days post-transplantation. No chronic or late developing acute GVHD was observed even though the animals received succinylacetone as the sole immunosuppressant for only 28 days after transplantation. Furthermore, hemopoietic reconstitution in recipients of syngeneic cells was essentially identical between the control group and the group treated with succinylacetone. In addition, no gross or histologic evidence for renal, hepatic, cardiovascular, endocrine, or neurologic toxicity was observed in the long term transplant survivors treated with succinylacetone. These data indicate that succinylacetone treatment is effective in preventing lethal GVHD in this allogeneic bone marrow transplantation system while permitting normal hemopoietic reconstitution in the absence of significant chronic toxicity to other major organ systems.

Animals↗

PubMed1987

The fungicide methyl 2-benzimidazole carbamate causes infertility in male Sprague-Dawley rats.

A serial breeding technique was used to evaluate the fertility of male Sprague-Dawley rats after exposure to the fungicide carbendazim (methyl 2-benzimidazole carbamate). Proven-fertile male rats (90 days old) received 10 daily doses of corn oil or carbendazim (400 mg/kg/day) peroral. Each male was bred with a new female each week; breeding began on the third day of treatment and continued for 32 wk after the last day of chemical exposure. Twelve days after each breeding period, the females were killed, their uteri were examined for resorptions, and the number of dead and viable fetuses was determined. All males were killed 35 wk post exposure, and testicular tissue was prepared for histopathological examination by vascular perfusion. Fertility (percent fertile as indicated by pregnant females) of males in the carbendazim-treated group was depressed the first post-exposure week; 10 of the 24 treated males failed to produce a pregnant female as compared with no failures in the control group. By the fifth post-exposure week, 16 of the 24 carbendazim-treated males were infertile. Of these 16 males, 4 recovered fertility after a failure to produce a pregnant female for 5-11 consecutive breeding periods. However, 12 of the males did not recover fertility during the remainder of the 32-wk post-exposure period. Histological examinations of testicular sections 245 days post exposure revealed that exposure to carbendazim caused severe seminiferous tubular atrophy (greater than 85% of tubules were atrophic) in those carbendazim-treated males that failed to recover fertility.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Ultrastructure of spermatozoa from domesticated birds: comparative study of turkey, chicken and guinea fowl.

Typical for non-passerine birds, the spermatozoa of the turkey, chicken and guinea fowl were vermiform with a maximum width of 0.5-0.7 micron and lengths of 90 microns for chicken sperm, and 75-80 microns for those of the turkey and guinea. An acrosome, nucleus, midpiece and flagellum could be distinguished by SEM. The acrosomal cap projected over a perforatorium surrounded by granular material. At its base, the cap encircled apical projections of the nucleus. The nucleus consisted of dense chromatin, and formed a concave implantation fossa where it joined the midpiece of the tail. For turkey and chicken spermatozoa, the neck region of the midpiece consisted of a proximal centriole and its pericentriolar processes oriented perpendicularly to an elongated distal centriole, but guinea sperm contained only a single elongated centriole and associated pericentriolar projections. The centrioles plus their projections to the implantation fossa constituted the non-striated connecting piece. The distal centriole served as the precursor of the flagellum and was longest for turkey sperm. Enveloping the distal centriole and extending to the annulus were 25-30 helically arranged mitochondria. Flagellum ultrastructure consisted of the typical 9 + 2 microtubular axonemal complex but outer dense fibers were absent. A hypertonic diluent immobilized the sperm, condensing the flagellar matrix and obliterating the radial links. Variations in ultrastructure of the above structures between sperm of the three species is discussed and compared with sperm ultrastructure from other non-passerine birds.

Animals↗

PubMed1986

Frequency and structure of macrophages and abnormal sperm cells in guinea fowl semen.

Semen from young and old guinea fowl was examined for macrophages and abnormal sperm cells. Large numbers of macrophages were found in the semen from both groups. However, there were significantly more abnormal sperm cells in the semen of the young males. The abnormal cells consisted of large coiled cells, bent spermatozoa, and round-headed cells. The predominant abnormality in the young males was bent sperm, although their semen also contained large round cells. The large round cells were identified as abnormal spermatids by electron microscopy and were more prominent in the older males. The abnormal spermatids were pleomorphic and exhibited various stages of intermediate and late spermatid development. The macrophages were activated cells that exhibited phagocytosis of large number of normal spermatozoa but were never observed to engulf abnormal cells. Their ultrastructure consisted of numerous lipid droplets, vesicles of ingested spermatozoa, lysosomal structures, residual bodies, and undigested remnants of spermatozoa. The presence of macrophages and abnormal spermatids in semen has been associated with lowered fertility in other species; thus, semen with exorbitant numbers of these cells should not be used for artificial insemination of the guinea fowl.

Acrosome↗

PubMed1986

Testicular toxicity and infertility in male rats treated with 1,3-dinitrobenzene.

Weanling male Sprague-Dawley rats were gavaged 5 d/wk with 1,3-dinitrobenzene (m-DNB) at dosages of 0, 0.75, 1.5, 3.0, and 6.0 mg/kg X d. Males were bred to untreated females during treatment wk 10 and were killed during treatment wk 12. Although males dosed with 3 mg/kg X d inseminated the females and evidence of mating was observed in males dosed with 6 mg/kg X d, none of the males in these groups sired litters. Diminished sperm production (reduced testicular sperm head counts), decreased cauda epididymal sperm reserves, nonmotile spermatozoa, atypical sperm morphology, decreased weights of the testes and epididymides, seminiferous tubular atrophy, and incomplete spermatogenesis were also observed in these groups. Sperm production was also decreased in males dosed with 1.5 mg/kg X d. Changes in the spleen included increased weight at dosages of 1.5 mg/kg X d or higher and splenic hemosiderosis, which ranged from slight in rats treated with 0.75 mg/kg X d to moderately severe in those dosed with 6 mg/kg X d. The data indicate that m-DNB is a potent testicular toxicant in the male rat, capable of producing extensive damage to reproductive tissues and reproductive failure. Limited data on four rats that received 6 mg/kg X d and were allowed a 5-mo posttreatment recovery period suggested that the testicular effects are at least partially reversible.

Animals↗

PubMed1985

Augmentation of hematoporphyrin uptake and in vitro-growth inhibition of L1210 leukemia cells by succinylacetone.

Succinylacetone (SA; 4,6-dioxoheptanoic acid), a specific inhibitor of delta-aminolevulinic acid dehydrase (ALAD) (the second enzyme of the heme biosynthetic pathway), was tested for its effect in L1210 cells from inbred DBA/2 mice. ALAD from broken L1210 cells was completely inhibited by 1 microM SA, but in whole cells activity was decreased only 83% after incubation of the cells with 2.5 mM SA for 3 days. When incubated with hematoporphyrin (HP), L1210 cells rapidly took up porphyrin from the medium, and this uptake could be augmented by pretreatment of the cells with SA; but this enhancement of porphyrin uptake occurred gradually over a period of days. When SA-treated and untreated L1210 cells were incubated with increasing concentrations of HP in the medium, SA-treated cells reached the saturation concentration of cellular porphyrin at lower medium HP concentrations than did untreated cells. Growth of L1210 cells could be inhibited by 2 mM SA or more. Addition of increasing amounts of serum to cultures of cells containing SA did not reverse the growth inhibition due to SA. Porphyrin uptake from HP in the medium in nonmalignant fibroblast line 3T3 was much lower than in L1210 cells and could not be enhanced by incubation of the cells with SA.

Animals↗

PubMed1984

Protein, cholesterol, acid phosphatase and aspartate aminotransaminase in the seminal plasma of turkeys (Meleagris gallopavo) producing normal white or abnormal yellow semen.

Turkeys which produce yellow semen have abnormal ductuli efferentes' epithelial morphology, with blebbing of cytoplasmic material into the ductal lumen. This could possibly increase the activity or concentration of seminal plasma components. In the present study, seminal plasma from 270 Large White breeder turkeys was evaluated for protein and cholesterol concentrations and the activities of acid phosphatase and asparate aminotransaminase. In a separate experiment, protein concentrations of turkey seminal plasma were estimated by biuret or Bradford methods. Bradford estimates were 46.6% less than those obtained with the biuret assay, using bovine serum albumin as the standard. Estimates of seminal plasma protein concentration in the main study were obtained using the Bradford method, and should be adjusted accordingly when compared with other studies using the biuret technique. Abnormal yellow seminal plasma, compared to normal white seminal plasma, had elevated levels of total protein and cholesterol and increased activities of acid phosphatase and aspartate aminotransaminase. Overall means were: 14.3 mg/ml, 38.9 mg/dl, 232.6 IU/ml, 81.0 IU/ml, respectively. Correlation coefficients for cholesterol concentration, acid phosphatase and aminotransaminase activity with protein concentration were +0.65, 0.70 and 0.50 (P less than 0.0001), respectively. Specific activities of both enzymes showed a significant reduction as seminal plasma protein increased, indicating a disproportionate increase in proteins other than these enzymes in yellow seminal plasma.

Acid Phosphatase↗

PubMed1984

Seminal plasma androgen-binding protein activity in turkeys with normal white or abnormal yellow semen.

Dihydrotestosterone (DHT) binding activity of normal white and abnormal yellow turkey semen was quantitated by disc-gel electrophoresis in the presence of [3H]DHT. White seminal plasma had three peaks of activity (Rf = 0.3, 0.5 and 0.8). Yellow seminal plasma had a greater protein concentration and [3H]DHT binding activity averaging 32.5 +/- 7.93 pmol DHT/ml compared with 1.45 +/- 0.3 pmol DHT/ml for white seminal plasma. The majority of [3H]DHT binding was localized at Rf = 0.5 for the yellow seminal plasma. When labelled samples were separated by electrophoresis on unlabelled gels, the only peak of activity was at Rf = 0.5. Blood serum contained 3 peaks of activity (Rf = 0.4, 0.5, and 0.8). We conclude that a seminal plasma androgen-binding protein is present in the domestic turkey, and in males with yellow semen syndrome androgen-binding activity is increased.

Androgen-Binding Protein↗

PubMed1984

Detection and incidence of yellow turkey semen on commercial breeder farms.

Seminal plasma from 270 commercial Large White breeder turkeys (30 males from each of nine farms) was evaluated for protein concentration, color, and opacity. Yellow semen syndrome (YSS) was detected by identifying seminal plasma having both a yellow color and a high protein concentration (greater than 20 mg/ml) and was present in 11.8% of the males. Normal white semen males, with seminal plasma protein less than 20 mg/ml and white or slight yellow in color, were found in 85.9%. Using this method only 3.3% of the males did not fit either category. Protein concentrations were clustered near 10 mg/ml but values ranged from 3.7 to 79 mg/ml. A low protein group (less than 8 mg/ml; 13.3% of the males) had 34 white, 2 slight yellow, and 0 yellow samples. A median protein group (10 mg/ml; 74.1%) had 175 white, 21 slight yellow, and 4 yellow. The high protein group (greater than 20 mg/ml; 12.5%) had 2 white, 14 slight yellow, and 18 yellow. There was large variation among farms, ranging from 0% to 23.3% YSS. Protein concentration was not correlated with the age of the males, and opacity of the seminal plasma was lowly correlated with color (r = .17; P less than .01). Refractive index was useful for estimating the seminal plasma protein concentration (r = .87; P less than .0001), which along with color, could be used as a simple method for estimating the quality of turkey semen on the farm.

Animal Husbandry↗

PubMed1983

Growth inhibitory activity of succinylacetone: studies with Walker 256 carcinosarcoma, Novikoff hepatoma and L1210 leukemia.

Succinylacetone (SA, 4,6-dioxoheptanoic acid) inhibits d-aminolevulinic acid dehydrase, the second enzyme of the heme biosynthetic pathway and thereby inhibits heme biosynthesis. In the present study SA is shown to inhibit the growth of the Walker carcinosarcoma (W256) in vitro and in vivo, the Novikoff hepatoma in vivo, and L1210 leukemia in vitro, but only slightly in vivo. Rats can tolerate significantly larger doses of SA for at least twice as long as were administered in the present study without gross evidence of toxicity. In contrast to findings in previously published studies with murine erythroleukemia cells, the inhibition of growth of L1210 and W256 cells by SA in vitro is not accompanied by a decrease in cellular heme and is not reversed by addition of hematin to the medium. This suggests a second mechanism of growth inhibition of tumor cells unrelated to heme biosynthesis. Although the growth of both W256 and L1210 cells was markedly inhibited by the same concentration of SA in culture, there was a great difference in responsiveness in vivo, in that much greater inhibition of the growth of the Walker tumor was produced by SA.

Animals↗

PubMed1983

Characteristics of hematin uptake in malignant, embryonic and normal cells.

The characteristics of hematin uptake were examined in three malignant cell lines [L1210 leukemia, 745 murine erythroleukemia (MEL) and Walker carcinoma (W256)], a cell line derived from normal rat liver (BRL-3A) and a normal embryonic cell, chick embryo fibroblasts (CEF). Uptake in the normal liver cell line was slight and occurred at a slow rate in contrast to the rapid uptake, which was more rapid and of greater magnitude in the three tumor cell lines, Saturation of the heme uptake mechanism was observed in MEL cells at an extra-cellular hematin concentration of 160 micro M and in L1210 cells at 300 micro M. At saturation L1210 cells achieved a cellular heme concentration nine times as high as MEL cells. Hematin uptake in MEL cells was markedly augmented by pretreatment with DMSO, procaine, detergent or proteolytic enzymes or by increases in the pH of the medium from 8 to 9.5. In contrast to MEL cells where SA inhibits growth by lowering cellular heme, the inhibition of growth of L1210 cells by SA appears to operate by a mechanism independent of heme. In gradual increase in hematin uptake capacity in MEL cells over a period of days. Afer exposure of MEL cells to a high concentration of hematin in the medium, the egress of heme was followed under various conditions. Of the various agents studied, only cyanide produced a loss of heme from MEL cells.

Absorption↗

PubMed1982

Neonatal deaths and pulmonary dysplasia due to D-penicillamine in the rat.

D-penicillamine, added to a low copper diet fed through pregnancy or given by gavage to pregnant rts which were on a copper-deficient or a normal diet produced fetal resorptions and malformations. Doses of 300 to 400 mg per day for 6 days (days 9-14 or gestation) with a diet normal for copper prevented maternal weight gain and at 350 or 400 mg/day caused fetal death on day 16 or 17. Forty percent of offspring had tracheobronchomegaly and 42% had cystic lungs. Associated abnormalities included pleural hemorrhages, dilated esophagi, and anaerated lungs. The lungs had large, poorly formed, thick-walled acini without partitioning and a thick rim of connective tissue around vessels and bronchi. At the higher doses, all members of one of 12 litters had angulation of the spine and half the members of another litter had cleft palates. A postulated mechanism for these alterations in pulmonary connective tissue productive of malformations which model human tracheobronchomegaly and cystic lungs, is interference with lysyl oxidase, a copper-requiring enzyme, which cross-links elastin.

Abnormalities, Drug-Induced↗

PubMed1982

Perinatal death and respiratory apparatus dysgenesis due to a bis (dichloroacetyl) diamine.

N, N1-bis (dichloroacetyl) diamine 1, 8-octomethylenediamine (WIN 18,446) is an experimental drug which was first investigated as a male contraceptive. It is soluble in lipid solvents but not in water. The administration of 1,200 to 1,600 mg/kg to pregnant rats on the tenth day of gestation produced multiorgan fetal malformations. Smaller doses, 400 to 800 mg/kg, especially if divided over 2 or 3 days, caused perinatal death. Thus, 60 to 100% of offspring of rats given WIN 18,446 on the tenth and 11th days of gestation died at birth or within 4 days (Taleporos et al., 78). The present study investigated such deaths. At doses of 200 mg/kg on day 10 or 50 mg/kg on days 10 and 11, 67% of offspring had defective or absent diaphragms, 48% had tracheobronchiomegaly with cystic lungs, and 67% had pleural hemorrhage. At doses of 100 mg/kg given on 1 day or 25 mg/kg each day for 2 days, 50% had tracheobronchiomegaly with cystic lungs and rudimentary acini. At lower doses (18.8 mg/kg X 2 or 12.4 mg/kg X 3), a majority of fetal lungs had rudimentary acini, thick septa, few capillaries, and wide cuffs of perivascular connective tissue. Thus, a chemical given during organogenesis produced dysgenesis of the respiratory apparatus. Varying the dose produced malformed lungs with persistently deficient acini which model such human lung faults as tracheobronchiomegaly (Mournier-Kuhn Syndrome; Mounier-Kuhn, '32), bronchiolar dysplasia (Wilson-Mikity Syndrome), and perinatal death with acinar failure resembling neonatal hyaline membrane disease.

Abnormalities, Drug-Induced↗

PubMed1982

Morphology of the epididymal region of turkeys producing abnormal yellow semen.

Male turkeys producing abnormal yellow-colored semen (YS) had hypertrophied epithelial cells in the ductuli efferentes. The cells were engorged with cytoplasmic, lipid-like (lipoid) droplets, a morphological abnormality found exclusively in this area of the epididymal region. The testes, epididymal region, ductus deferens, and abdominal fat were relatively yellow compared to turkeys producing normal white semen (WS). Adipose tissue within the abdominal cavity and lining the ductus deferens was more abundant in the YS producers. In addition to increased lipoid droplets, nonciliated cells of the ductuli epithelia contained larger and more numerous electron-dense lysosomal bodies than similar nonciliated cells in WS males. Resorption of morphologically normal and abnormal spermatozoa by the epithelia of the ductuli efferentes was prevalent in the YS males but was not observed in the WS turkeys. The seminal fluids in the epididymal region of the YS males contained abnormal spermatids, cellular debris, and increased amounts of electron-dense proteinaceous material.

Animals↗

PubMed1982

Ultrastructure of the guinea fowl (Numidia meleagris) spermatozoon.

The ultrastructure of guinea spermatozoa was characterized by transmission and scanning electron microscopy. The average lengths and widths (measured at the widest points) of the segments were as follows: acrosome, 1.8 x .47 mu; nucleus, 12.8 x .49 mu; midpiece, 3.9 x .59 mu; flagellum, 59 x .52 mu. Thus, the guinea sperm cell is slightly smaller than the chicken or turkey spermatozoon. The ultrastructure of the guinea spermatozoon was similar to that of the chicken and turkey with two exceptions: 1) the mitochondria had cristae aligned parallel and oblique with respect to the outer limiting membrane and 2) there was no proximal centriole, the distal centriole projected into the implantation fossa with "arms" of the nonstriating connecting piece extending laterally from the centriole to the implantation fossa.

Animals↗

PubMed1982

Seminal plasma free amino acids and seminal and blood plasma proteins of the guinea fowl (Numidia meleagris).

Glutamic acid was the major free amino acid in guinea seminal plasma, representing 90.00% of the total amino acids. Threonine comprised 3.74%, aspartic acid 3.23%, and serine 1.50%. Others were detected at less than .50% of the total free amino acids. Blood plasma protein concentration and SE were 2.68 +/- .35 g/100 ml, and the proteins were fractionated by disc acrylamide electrophoresis into seven major bands: albumin, alpha-1, a dense beta fraction, and four postbeta, or gamma, proteins. Seminal plasma protein concentration and SE were .45 +/- .03 g/100 ml, and the proteins separated into nine fractions: albumin, alpha-1 and -2, beta-1, -2, and -3, and three postbeta, or gamma, bands.

Amino Acids↗