The effects of three reproductive hormones and cortisone on the replication of avian infectious bronchitis virus in vitro

The in-vitro effects of three reproductive hormones (progesterone, oestrogen testosterone), and cortisone on the replication of infectious bronchitis (IB) virus strain G were investigated over a period of 36 hours using tracheal organ cultures as the culture system. The non-toxic concentration of each hormone for the culture system was first determined. These were found to be 3 micrograms/ml for progesterone, testosterone, and cortisone, and 1 micrograms/ml for oestrogen. The results were based on the assay of the extracellular virus production from both hormone treated and untreated infected cultures at specific intervals up to and including 36 hours. While oestrogen, testosterone, and cortisone were found to enhance the replication of the virus, no significant effect was noticed following treatment with progesterone.

Thromboxane and prostacyclin release after endotoxin infusion in the rat

To determine in the rat whether pulmonary artery hypertension accompanies thromboxane release, we sequentially monitored pulmonary and systemic artery pressures and cardiac output. We measured pulmonary and aortic plasma levels of TxB2 as well as 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) in awake unrestrained adult male Sprague-Dawley rats given a single infusion of endotoxin at the relatively high dose commonly administered to this endotoxin-resistant species. At 40 min after endotoxin infusion, both pulmonary and aortic TxB2 and 6-keto-PGF1 alpha levels increased nine-fold and seven-fold above baseline, respectively. In the pulmonary artery, 40 min after infusion, both mediator levels differed significantly from baseline (p less than 0.05), whereas in the aorta, because of marked variance in the response of different animals, only the 6-keto-PGF1 alpha levels achieved significance (p less than 0.05). These changes were associated with a fall in systemic blood pressure and cardiac output, but no demonstrable rise in pulmonary artery pressure (PAP). Despite ultrastructural evidence of vascular injury, these data indicate that in the rat thromboxane and prostacyclin release following a single infusion of endotoxin is not associated with pulmonary hypertension and that increased prostacyclin production may contribute to systemic hypotension.

Localisation of avian reovirus in the hock joints of chicks after entry through broken skin

Avian reoviruses are transmitted vertically via the egg and horizontally following the ingestion of infected faecal material. Experiments conducted on eight one-day-old specific pathogen free chicks provide evidence for occasional infection through broken skin and localisation in the hock joint.

Different sensitivities of Vero cells from two sources to avian reoviruses

Four strains of avian reovirus were each titrated in two batches of Vero cells (A and B) from different sources and different media recommended for each batch. For each strain, variations in titre were observed under the different cultural conditions. In one case the discrepancy between the titre in A cells with medium recommended for B cells, and B cells with A medium was 2.1 log10. Attention is drawn to the possibility that important differences in sensitivity may exist between batches of Vero cells from different sources and these may be exaggerated by the use of different media.

The cycle of the seminiferous epithelium in the Japanese quail (Coturnix coturnix japonica) and estimation of its duration

A regular, well defined spermatogenic cycle was found in the Japanese quail by examining thin sections of isolated lengths of seminiferous tubules embedded in epoxy resin to resolve the structure of developing spermatids. The stages of the cycle initially were identified in studies using a preparatory method for fixation which separated adjacent cellular associations. The cycle was divided into 10 stages with relative frequencies (%) of Stages I to X respectively of: 11.9, 14.8, 24.1, 10.3, 8.2, 6.4, 9.4, 5.5, 3.8 and 5.4. The duration of one cycle was 2.69 +/- 0.08 days (mean +/- s.e.m.) as determined by intraventricular injection of [3H]thymidine and autoradiographic examination of the testes 1-4 days later. It was estimated that lifespans were 2.01 days for type B spermatogonia, 3.86 days for primary spermatocytes, 0.15 days for secondary spermatocytes, and 4.54 days for spermatids. The results suggest that the kinetics of spermatogenesis in the quail are fundamentally similar to the pattern in mammals.

Carcinogenicity tests of fecapentaene-12 in mice and rats

Fecapentaenes, a class of direct-acting bacterial mutagens, have been isolated from the feces and intestinal tract of humans on a Western meat-containing diet. Two bioassays to test pure fecapentaene-12 (FP-12) for carcinogenicity were performed. FP-12 in dimethylsulfoxide (DMSO) solution was injected i.p. into newborn ICR/MA mice on days 1, 3, 7, 10, 14 and 21. The mice killed after 21 months had neoplasms in liver, lung, glandular stomach and subcutaneous fibrosarcoma. Intrarectal (i.r.) infusion of FP-12 in an aqueous vehicle into male F344 rats for 71 weeks, and killing the rats after 21 weeks more, displayed no evidence of neoplasia associated with FP-12 exposure. The positive control, N-nitrosomethylurea (NMU), given i.r. as 4 2-mg doses in 2 weeks, as expected, yielded multiple colonic neoplasms in less than 11 months. Fecapentaene may exert its effect in bacteria and in newborn mice through the generation of hydroxy radicals. However, adult rodent and human colon may have adequate biochemical defense mechanisms against low level, even continuous exposures to chemicals like FP-12, and thus be at low risk of neoplasia, as was found.

Stimulation of protein secretion in the initial segment of the rat epididymis by fluid from the ram rete testis

Zone 1A of the ductus epididymidis was perfused with ovine rete testis fluid (nRTF) and modifications of it, and a synthetic medium (sRTF) based on the inorganic composition of nRTF. There was little fluid transport by the duct mucosa and nRTF stimulated protein secretion. The secretagogue activity was not extracted by charcoal, was sensitive to protease digestion and was present in a portion of nRTF with a molecular weight of greater than 10,000. The addition of bovine serum albumin to the sRTF stimulated protein secretion, but not to the same extent as equal amounts of protein in nRTF. Polyacrylamide gel electrophoresis of the perfusates showed that proteins with molecular weights of 19,000 (all rats studied), and 22,000, 30,000 and 60,000 (at least half the rats studied) were secreted into the perfusion fluids as well as some blood proteins, but the pattern of secretion was not affected by the composition of the perfusion fluid.

Prevention of formation of important mutagens/carcinogens in the human food chain

Etiological factors for gastric cancer, among others, involve consumption of smoked, salted, and pickled fish of certain types. Their chemical nature is not yet fully established but probably involves diazo phenols, and their formation can be prevented either by omitting the salting and pickling process, or by using vitamins C and E on the food prior to salting, pickling, or smoking. Both preventive approaches would limit the formation of mutagenic and carcinogenic diazo phenols. Sugimura and associates discovered new types of mutagens as heterocyclic amines that are formed during frying or broiling of meats and fish. In rats, these amines induce cancer specifically in organs such as breast, colon, or pancreas, associated with Western-type nutrition where promotional elements such as dietary fat play an enhancing role. Thus, inhibition of the formation of these new carcinogens during cooking would remove the genotoxic components from the diet. Mixing 10% soy protein with ground meat prior to frying prevents the formation of these mutagens presumably by affording a lower surface temperature. More effective is the addition of tryptophan, proline, or mixtures thereof, which specifically blocks the formation of these mutagens/carcinogens, probably by competing for reactive intermediary aldehydes, so that these cannot interact with the normal essential target, creatinine. Thus, we have available practical, yet science-based, mechanistically understood procedures to prevent the formation of carcinogens associated with important types of cancer prevalent in many countries.

Biliary lithotripsy

At Baylor University Medical Center in Dallas, we began performing lithotripsy with the Medstone STS lithotripter for gallstones in January 1988 and in the first year treated 81 patients. Fifty-five of these patients were available for 4-month follow-up. We randomized half of the patients to receive ursodeoxycholic acid for 7 days prior to lithotripsy and gave all of the patients ursodeoxycholic acid after lithotripsy. Only 10.4 percent of the patients who contacted us ultimately proved to be candidates for lithotripsy. Gallstone fragmentation occurred in 95 percent of all patients and in 97 percent of those patients with solitary stones under 20 mm in size. The rate of clearance for solitary stones less than 20 mm in size was 50 percent. Unfavorable effects ascribable to lithotripsy were infrequent. All of the patients had pain before treatment, and one-third complained of biliary colic after treatment. Minor skin bruising which resolved in 1 to 5 days was found in 20 percent of the patients. This study lends credence to the findings of previous studies and demonstrates that lithotripsy combined with bile acid therapy is a useful therapy for cholelithiasis.

Effects of dimethylthiourea on chronic hypoxia-induced pulmonary arterial remodelling and ventricular hypertrophy in rats

Ischemia, followed by reperfusion and restoration of oxygen to tissues, generates hydrogen peroxide which in turn generates injurious free radicals, particularly hydroxyl. Chronic hypoxia may also result in liberation of free radicals. In rats, chronic hypoxia causes pulmonary hypertension, associated with structural remodelling of pulmonary arteries, polycythemia, and vasoconstriction. We studied in rats the effects of dimethylthiourea (DMTU), a hydroxyl and hydrogen peroxide scavenger, on acute hypoxic vasoconstriction, and on the arterial structure and development of polycythemia after chronic hypoxia (FIO2 0.10 for 10 days, daily DMTU). DMTU did not affect acute vasoconstriction nor polycythemia. It significantly reduced muscularization of alveolar wall and alveolar duct arteries, medial thickening of alveolar wall and preacinar arteries, and right ventricular hypertrophy, suggesting reduction of pulmonary hypertension. However, DMTU caused marked growth retardation in both control and hypoxic rats, an effect not previously described. In other rats a similar degree of growth retardation due to reduced food intake failed to prevent the effects of hypoxia, suggesting that DMTU's effect is not through this mechanism. The results of this study support but do not confirm the hypothesis that free radicals may have a role in the pathogenesis of the arterial structural changes in the microcirculation contributing to chronic hypoxic pulmonary hypertension. However, in view of DMTU's effects on growth, definitive testing of the hypothesis will not be possible until other, less toxic, chronic hydroxyl scavengers become available.

Growth factor activity in luminal fluids from the male reproductive tract of the ram, rat, tammar wallaby (Macropus eugenii) and Japanese quail (Coturnix coturnix japonica)

Growth factor activity in luminal fluids from the male reproductive tract was assayed by measuring the stimulation of [3H]thymidine incorporation into BALB/c 3T3 fibroblasts. The potency of fluids from the rete testis of the rat, ram, tammar wallaby and Japanese quail was much the same. However, about 90% of the activity in fluid from the rete testis of the rat and tammar was lost during its passage through the epididymis.

Effects of certain stress factors on the re-excretion of infectious laryngotracheitis virus from latently infected carrier birds

Experiments were set up to assess the effects of ‘natural’ and ‘artificial’ stresses on the re-excretion of infectious laryngotracheitis (ilt) virus in latently infected chickens recovered from the acute phase of the disease. The stresses were rehousing with the addition of ilt-free contact birds, corticosteroid treatment and the onset of lay. The contact birds were also monitored for transmission of the virus from the carrier birds. Rehousing with unfamiliar birds induced ilt virus shedding in one of five birds and there was evidence of transmission from this bird to its mate. The onset of lay had a significant effect on the overall shedding rates of the carrier birds. Nine of 10 birds shed virus after onset of lay compared with only two in the three-and-a-half weeks before, and there was a highly significant increase (P<0·001) in the overall number of virus isolations during this period. Corticosteroid treatment did not affect virus shedding. These results may explain some of the apparently spontaneous outbreaks of ilt which occur in the field.

Biliary lithotripsy in the United States

We have reported the case of a patient whose gallstone was completely fragmented by lithotripsy; all demonstrable particles passed completely within 36 hours. The patient required no analgesics and had no complications from the procedure. This is the first case of gallstones successfully treated solely by a combination of lithotripsy and bile acid therapy in the United States under an FDA-approved IDE protocol.

Effects of certain stress factors on the re-excretion of infectious laryngotracheitis virus from latently infected carrier birds

Experiments were set up to assess the effects of 'natural' and 'artificial' stresses on the re-excretion of infectious laryngotracheitis (ILT) virus in latently infected chickens recovered from the acute phase of the disease. The stresses were rehousing with the addition of ILT-free contact birds, corticosteroid treatment and the onset of lay. The contact birds were also monitored for transmission of the virus from the carrier birds. Rehousing with unfamiliar birds induced ILT virus shedding in one of five birds and there was evidence of transmission from this bird to its mate. The onset of lay had a significant effect on the overall shedding rates of the carrier birds. Nine of 10 birds shed virus after onset of lay compared with only two in the three-and-a-half weeks before, and there was a highly significant increase (P less than 0.001) in the overall number of virus isolations during this period. Corticosteroid treatment did not affect virus shedding. These results may explain some of the apparently spontaneous outbreaks of ILT which occur in the field.

Dietary beta-carotene in rat models of gastrointestinal cancer

The effect of dietary beta-carotene (BC) was investigated in models of gastric and colonic carcinogenesis. Male Wistar rats were fed a diet with 0.4% BC during weaning, then 0.2% BC throughout. Cancer in the stomach and small intestine was induced by giving 80 mg/l N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in drinking water for 52 wk, but BC failed to affect carcinogenesis under these conditions, although the incidence of gastric adenocarcinoma was reduced slightly. Neoplastic and nonneoplastic lesions in the liver, skin, and pancreas were also present to a similar extent with BC feeding and without BC. Colorectal cancer was induced by six 2 mg intrarectal infusions of MNNG per rat over a 3-wk period, with the rats held another 22 wk without an inhibitory effect by BC. Thus, 0.2% dietary BC failed to influence significantly the development of neoplasia induced by a direct-acting carcinogen in the gastrointestinal tract.

Characterization of aminoalkylimidazol-4-one mutagens from liquid-reflux models

A new class of low molecular weight, aminomethylimidazol-4-one (IQ-"like") mutagens have been produced by the reaction of creatinine with the amino acid L-threonine, in liquid-reflux models, mimicking cooking, of diethylene glycol:5% distilled water (2 h at 150 degrees C). Two mutagens, 2-amino-1-methyl-5-propylideneimidazol-4-one (AMPI) and 2-amino-5-ethylidene-1-methylimidazol-4-one (AEMI) were isolated and characterized by UV absorption spectra, mass spectra, and 1H-NMR. The mutagen AEMI was identical to that obtained from the reaction of creatinine with acetaldehyde. These mutagens were positive in all IQ-sensitive Ames tester strains and were not inactivated by acidic nitrosation at pH 1.0. Products displaying mutagenicity were also obtained by refluxing creatinine with other hydroxyamino acids such as L-serine, L-homoserine, and L-4-amino-3-hydroxybutyric acid, and aldehydes such as glyoxal, methylglyoxal, glycolaldehyde, but not formaldehyde. Simple model systems such as creatinine and acetaldehyde may be useful in more clearly defining the exact mechanism of formation of IQ-type mutagens (aminomethylimidazo-quinolines and -quinoxalines) produced during cooking, as well as in screening for potential inhibitors of IQ-type mutagen formation, and elucidating the mechanism of such inhibition.

Mechanisms of differential strain sensitivity in gastric carcinogenesis

The genetically-controlled, distinct sensitivity of different rat strains to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced cancer of the glandular stomach and duodenum was investigated. MNNG is activated through thiols, and the thiol content of the glandular stomach, duodenum, and liver of the BN rat tended to be slightly, but not significantly higher than that of the Wistar, Sprague-Dawley, Lewis, and Buffalo rats. The levels of the DNA repair system, O6-alkylguanine transferase (AGT), in sensitive Wistar strain rats had values similar to those in resistant Buffalo strain rats. Administration of 80 mg/liter of MNNG in the drinking water for six weeks up to the time of tissue collection yielded the same AGT levels. Of all the parameters examined to account for genetically-mediated sensitivity to gastrointestinal cancer induction, namely, N-denitrosation, thiol activation, AGT-related DNA repair, and cell duplication rates, the latter yielded the best association, although these factors acting together may be involved.

L-tryptophan inhibits formation of mutagens during cooking of meat and in laboratory models

The formation of mutagens and carcinogens of the 2-amino-3-methylimidazo[4,5-f]quinoline and -quinoxaline type, formed during the frying or broiling of meats and in liquid-reflux laboratory models, was inhibited by L-tryptophan in a dose-dependent fashion. Addition of 75 mg (1.04 mg/cm2 surface area) of L-tryptophan per side in a sauce to ground beef patties prior to cooking significantly blocked the formation of mutagens observed in control patties treated identically with sauce but without L-tryptophan. The sauce itself did not have a significant inhibitory effect. When a mixture of 35 mM glucose, 70 mM glycine, and 70 mM creatinine in diethylene glycol-water (95:5) was heated in a liquid-reflux model for 2 h at 150 degrees C, the addition of 1.75-105 mM L-tryptophan gave a dose-related inhibition of mutagen formation, that reached 100% inhibition with 105 mM L-tryptophan.

Altered artery mechanics and structure in monocrotaline pulmonary hypertension

Pulmonary hypertension in rats, induced by an injection of monocrotaline, is associated with changes in the wall structure of the pulmonary arterial bed. We have studied the effects of this remodeling on mechanical properties of cylindrical pulmonary artery segments from rats 21 days after monocrotaline (MCT) injection. Resting and active (KCl induced) circumference-tension relationships were established for segments of extrapulmonary and intrapulmonary arteries isolated from the hilum and the fifth lateral branch from the axial pathway (all preacinar). The thicknesses of the vessel wall, the media, and adventitia were measured at several positions around the circumference of the artery by computerized analysis of histological cross sections of the segments fixed at a standard circumference. Resting and active stress were also calculated. The study shows that active circumferential tension and active stress are reduced in vessels from MCT-treated rats. Based on our findings, it is unlikely that altered contractile function of preacinar arteries contributes significantly to the increased vascular resistance seen in this model.

Multimodality treatment of locally advanced breast carcinoma

Forty patients with 41 locally advanced breast lesions at stages IIIA and IIIB and the inflammatory stage were treated with combined-modality therapy from July 1980 to August 1985. Treatment included induction chemotherapy consisting of three cycles of fluorouracil, doxorubicin hydrochloride, and cyclophosphamide, followed by mastectomy in those patients whose lesions were operable (n = 28), and resumption of chemotherapy. Nine patients received postoperative radiation therapy. The mean follow-up was 34 months. Greater than 50% reduction in tumor size was achieved in 72% of patients after three cycles of chemotherapy. Overall, local control was achieved in 85% of patients with 59% survival and 53% disease-free survival, while 10% of patients developed local recurrences. Excluding lymphedema of the upper extremity (n = 2) and inflammatory carcinomas (n = 4), local control was achieved in 96% of patients, with 75% survival and 68% disease-free survival, while 4% of patients developed local recurrences. The rate of disease-free survival was 71% in patients with partial response to chemotherapy, contrasted with 43% in patients who did not respond or only minimally responded to chemotherapy. Actuarial five-year survival, based on life-table analysis, was calculated to be 46% for the group overall, 58% for the group excluding lymphedema of the upper extremity and inflammatory carcinoma, and 56% for the 28 patients undergoing mastectomy.

Upper extremity fractures in the acute spinal cord injured patient

Fifty-three long bone upper extremity fractures in 46 patients with recent spinal cord injuries were reviewed with reference to the outcome of operative versus nonoperative treatment. Twenty-four fractures had surgery and 29 fractures were treated nonoperatively. Criteria used in assessing outcome included range of motion, time to union, total rehabilitation time, and orthopedic and medical complications. Humeral fractures had similar outcomes with either operative or nonoperative treatment. Radial nerve injury occurring with humeral fractures prolonged the rehabilitation time. All three combined radial and ulnar fracture treated surgically developed synostosis whereas two of the three nonoperatively treated fractures had other orthopedic complications. Nondisplaced radial fractures responded appropriately to closed treatment. Displaced radial fractures treated nonoperatively had a high incidence of malunion. All ulnar fractures were treated operatively, and all achieved acceptable range of motion and fracture healing at the time of discharge. Medical complications such as deep venous thromboses and decubitus ulcers occurred more frequently in the nonoperatively treated group (28%) than in the operatively treated group (4%). Standard guidelines for upper extremity fracture care apply to the patient with a spinal cord injury. However, operative stabilization may be associated with a decreased risk of medical complications in these patients.

Distribution of 5 alpha-reductase in the epididymis of the tammar wallaby (Macropus eugenii) and dependence of the epididymis on systemic testosterone and luminal fluids from the testis

The activity of 5 alpha-reductase was much higher in the caput and corpus epididymidis than in the cauda epididymidis. Orchidectomy caused a reduction in 5 alpha-reductase activity in the caput and corpus epididymidis, and regression of the epithelium and reduction in mass of all regions of the epididymis. Subsequent testosterone therapy caused a substantial increase in amount of epithelium and overall mass of the cauda epididymidis but showed little or no increase in any of the responses measured in the caput and corpus epididymidis. We concluded that the caput and corpus epididymidis of the tammar respond to factors other than testosterone, probably some constituent in the luminal fluid, and therefore are homologous with the initial segments of the epididymis in eutherians.

Pathogenesis of experimental reovirus tenosynovitis in chickens: influence of the route of infection

Four groups of specific pathogen-free, day-old chicks were infected experimentally with an avian arthrotropic reovirus strain R2 by four different routes:--oral, subcutaneous, foot-pad and intra-articular. These groups were followed sequentially to study: pathological changes in the hock joints and liver; cloacal virus shedding and the presence of virus in hock joints; serological responses as determined by enzyme linked immunosorbent assay (ELISA), agar gel precipitation (AGP) and virus neutralization tests. All 4 infected groups developed arthritis or tenosynovitis with synovial hyperplasia and lymphocytic infiltration. Foot-pad and intra-articular routes of infection were found to advance the disease process by 2 to 3 weeks after infection by these routes were associated with superficial degenerative changes in articular cartilage. Antibodies were detected at 2 to 3 weeks p.i. by all 3 methods, but there were no significant differences between the patterns of serological response in the infected groups. Injection into the foot-pad appears to be the most convenient and effective parenteral route of experimental infection.

Studies of fluid and spermatozoal transport in the extratesticular genital ducts of the Japanese quail

Stereological studies of the spermatic ducts of the quail were carried out for comparison between different parts of the system and those of other species, and to provide a basis for future physiological studies. Duct length, surface areas and volumes of various components of the ducts were determined. Values were subsequently used to calculate net fluxes of fluid across the duct epithelium, spermatozoal velocity and the distribution of spermatozoa throughout the system. It was concluded that the extratesticular spermatic ducts are divided into 2 main parts: (1) the ductuli efferentes where spermatozoa spend a brief period (8 minutes) and which are adapted for considerable net fluid reabsorption (100 microliters/cm2/h), and (2) the connecting ducts, ductus epididymidis and ductus deferens where spermatozoa spend a longer period (24 hours) and which are involved in little net fluid transport (0.14-2.1 microliter/cm2/h). Most spermatozoa (92.3%) are located in the ductus deferens. The velocity of spermatozoal transport is much the same through the quail spermatic ducts (0.37 mm/min) as through the mammalian epididymis, the difference between classes in the duration of spermatozoal transport being due to differences in the distance that they travel. In a comparison between estimates of spermatozoal concentration using stereological methods and direct counts of spermatozoa in samples collected using micropuncture procedures it was concluded that both methods gave similar results.