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At least 289 records · Page 16Linked to original sources
PubMed1989

Bone induction in a composite allogeneic bone/alloplastic implant.

This study evaluated the morphogenetic properties of the bone matrix as a biological delivery system in a composite allogeneic bone/alloplastic implant placed in extraskeletal recipient sites in rats. Seventy-two allogeneic diaphyseal bone cylinders were chemosterilized to obtain autolyzed antigen-extracted allogeneic (AAA) bone and implanted in twenty 140- to 160-day-old rats. In 30 implants, porous hydroxyapatite biomatrix (HAB) was inserted into the AAA bone cylinders creating the composite implants. Serial sections from the specimens harvested at 23, 30, 45, 53, and 63 days showed that 84% of the AAA bone cylinders induced the differentiation of variable amounts of endochondral bone and that in 61% bone formed in the interior of the cylinders; 74% of the composite implants had no bone-inductive effect, recruiting instead macrophages and multinucleated giant cells at the HAB/mesenchymal interface. In all instances bone failed to form within the porous HAB or in proximity to the AAA bone matrix facing the interior of the cylinders. When present, bone formed only in localized areas within the matrix. Histologic analysis showed that high deposits of induced bone are correlated to high levels of matrix vascular invasion and mesenchymal cell aggregation. Within the limits of this study on rodents, the results suggest that the HAB inhibits and delays the local differentiation of induced bone in the composite implants.

Animals↗
PubMed2005

Analysis of DNA damage in sea lamprey (Petromyzon marinus) spermatozoa by UV, hydrogen peroxide, and the toxicant bisazir.

In this study we sought to demonstrate that Comet assay can be applied to sea lamprey sperm DNA fragmentation and used to describe the relationship between sperm DNA damage and sperm fertilizing ability. We show that the assay can be used reliably and accurately, and unlike in the case of mammals, there is no need for additional steps related to improvement of efficacy of lysis and DNA decondensation. This agrees with the presence of histone proteins in lamprey sperm. An increase in DNA fragmentation was noted during short-term storage of milt on ice (0-4 days). We demonstrated genotoxic effects of UV radiation and oxidative stress (exposure to hydrogen peroxide) and found that oxidative damage to sperm DNA was likely repaired after fertilization in the embryo. Repairing capacity of the oocyte toward sperm DNA lesions caused by UV was restricted. Toxic effect of p,p-bis-(1-aziridinyl)-N-methylphosphinothioic acid (p,p-bis(1-aziridinyl)-N-methylphosphinothioic amide), a sea lamprey chemosterilant, could not be linked to DNA fragmentation in the in vitro tests. Its genotoxicity in vivo may possibly be associated with other mechanisms of DNA degradation (oxidation or DNA-protein and DNA-DNA cross-linking). In conclusion, this study demonstrates that Comet assay can be successfully applied to monitor effects of environmental disturbances and imposed injuries in sea lamprey spermatozoa and possibly other species of ancient fish with acrosomal sperm.

Animals↗
PubMed2004

Efficacy of animal anti-fertility compounds against sea lamprey (Petromyzon marinus) spermatozoa.

Sterile-male-release technique is currently used to control the sea lamprey (Petromyzon marinus) population in the Great Lakes. The chemosterilant (bisazir) used in this program is extremely hazardous; special safety measures are necessary when handling this chemical. Therefore, replacement of bisazir with safer agents is desirable. In this study, we examined the effects of low-toxicity compounds with previously described spermicidal activity (mainly against mammalian sperm) on motility and fertilizing ability of sea lamprey spermatozoa. Nonoxynol-9, benzalkonium chloride, zinc acetate, cupric chloride, cysteamine, tannic acid and propranolol were able to inhibit both sperm motility and fertilizing ability. Effective concentrations of these spermicides ranged from 0.15 to 1%. Therefore, they can be potentially used in further study directed at in vivo sterilization of male sea lampreys.

Animals↗
PubMed2006

Contraception for population control in exotic carnivores.

There is an increasing demand for management of feral and wild carnivores; since many of them have become "pest species" by adapting successfully to changing environments, having substantial impacts on their prey species, and serving as reservoirs for infectious diseases. Also in captivity, a low adult mortality and an increase in longevity, especially in large carnivores, cause an urgent need for population management. This paper presents an overview on contraceptive strategies to control reproduction in carnivores. Factors that have to be considered before applying a certain method for fertility suppression are discussed. For birth control, several methods of hormonal chemosterilization, immunocontraception and pregnancy termination have been developed in domestic and captive exotic carnivores, but none of them are yet suitable for free-ranging animals. GnRH agonists, which suppress pituitary function very efficiently, are recommended in captive and domestic animals for reversible contraception. Immunological contraception, causing prolonged infertility after single application, is a promising approach for feral animals. However, a specific gamete or hormone-derived "self" antigen must be identified for each particular species.

Animals↗
PubMed1996

Equine piroplasmosis an update on diagnosis, treatment and prevention.

Two haemoprotozoan parasites, Babesia caballi and Babesia equi, can cause equine piroplasmosis. Due to the presence of potential tick vectors in areas so far unaffected by equine babesias, import and export regulations often require the serum testing of animals for evidence of infection. Although the complement fixation test (CFT) has been recommended for detecting the presence of antibodies to Babesia spp., it has been demonstrated to have several disadvantages, including false-positive results and low sensitivity for detecting latent infections. An enzyme-linked immunosorbent assay (ELISA) may be an alternative for increased and sensitive detection of acute and latent babesial infections, but its development to date has been hindered by a limited antigen supply and poor specificity. In vitro cultivation of both parasite species and the identification of parasite proteins for diagnostic use has facilitated the development of a highly sensitive and specific ELISA. For the direct detection of the parasites, DNA probes are now available. Several drugs are available for the treatment of equine piroplasmosis. For instance, diminazene diaceturate is effective in the chemosterilization of B. caballi and in the elimination of clinical signs in B. equi infections. Antitheilericidal drugs such as buparvaquone have been demonstrated to be effective in combatting disease due to B. equi and may--in combination with imidocarb--also eliminate the parasite. The control of equine piroplasmosis must include effective tick control, seromonitoring of animals and the application of chemotherapy.

Animals↗
PubMed2000

Effects of gossypol on sperm viability and plasma sex steroid hormones in male sea lamprey, Petromyzon marinus.

Male sea lampreys Petromyzon marinus were injected with different doses of gossypol acetic acid in an attempt to sterilize them for use in a program for controlling the sea lampreys through the release of sterile males. Two lots of sea lamprey were used in these experiments. The first lot was divided into three groups and fish were injected intraperitoneally (i.p.) with 0.2 ml 50% ethanol as a control group or with gossypol suspended in ethanol at 100 and 200 mg/kg. The second lot was also divided into three groups and fish were either injected i.p. with vehicle as controls or gossypol at 25 and 50 mg/kg. Sperm weight, concentrations and motility were recorded after 31, 36 and 40 days or 24, 28 and 33 days in lots 1 and 2, respectively. Blood was collected from the caudal vessel prior to injections with gossypol and after 40 or 33 days in lots 1 and 2, respectively. Plasma levels of estradiol-17beta (E2), testosterone (T), progesterone (P) and 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP) were measured by radioimmunoassay. At the end of the experiment, the testis were removed and fixed in Bouin's solution for histological examination. High mortality was observed at the day of injection in the group treated with 200 mg/kg (84.6%), 100 mg/kg (41.7%), and 50 mg/kg (25%). Sperm concentrations were higher in control fish in comparison to most of the treated groups during the first sperm sampling (day 31 or 24), but then differences disappeared. At each sampling, sperm motility was higher in control groups than in treated groups and significant differences were observed (e.g. between control and 50 mg gossypol/kg). Fertility, evaluated at optimized sperm/egg ratio (5 x 10(4) sperm/egg) did not differ among treatments and controls. Changes in mean plasma sex steroid levels in the various treated groups were not significant, but a trend of decreasing plasma E2 was observed with increasing dose of gossypol. The structure of the testis was examined at the end of the experiment using light microscopy and appeared to be unchanged in gossypol-treated lampreys as compared to that of control animals. These findings suggest that gossypol injection into lamprey interferes with some of the reproductive parameters. Although high mortality rate precludes a single i.p. injection of gossypol as a favorable mode of chemosterilization in the lamprey, it would be useful to reassess the means of transfer of gossypol to reproductive tissues. This notion is further supported by the results of an in vitro sperm toxicity assay which revealed that gossypol, at a dose of 100 microM, has an antifertility action in this species.

Animals↗
PubMed2005

Biological activity and chemical composition of the essential oil from Jamaican Hyptis verticillata Jacq.

The chemical composition of the essential oil obtained by hydrodistillation from the aerial parts of Hyptis verticillata Jacq. was elucidated by a combination of GC and GC-MS analyses. The oil was dominated by the sesquiterpenoids cadina-4,10(15)-dien-3-one (15.1%) (1) and aromadendr-1(10)-en-9-one (squamulosone) (30.7%) (2). The oil exhibited chemosterilant activities against the cattle tick, Boophilus microplus Canest., and toxic action against adult Cylas formicarius elegantulus Summer, the most destructive pest of sweet potato (Ipomoea species).

Animals↗
PubMed1980

Sterilizing effects of trimethylphosphate in Drosophila melanogaster.

Trimethylphosphate (TMP) causes aspermia in D. melanogaster males. If larvae are allowed to develop on standard maize-meal medium containing 0.002 M TMP or greater, the enclosing adult males, when placed on uncontaminated medium, exhibit a period of temporary sterility. Between test groups the period of sterility is most variable at the doses of 0.002-0.004 M, but at 0.005 M or greater is approximately 11-12 days. Near-lethal doses of about 20 g/kg by abdominal injection produces a temporary sterility in adults, whereas oral doses up to 0.02 M are ineffective. Oogenesis in females is not affected by doses which cause temporary sterility in males. In adult male D. melanogaster, which were treated as larvae with 0.01 M TMP in the food medium, the basal region of testes and seminal vesicles do not contain spermatozoa. Cytological examinations of the spermatids reveal ultrastructural changes which are characteristic of those seen in X/O and sterile-mutant males; they contain incomplete axial fibre complexes, abnormal development of the mitochondrial derivatives, and nuclei which fail to elongate and condense. Evidence from cytological studies of larval testes suggests that the chemosterilizing effect of TMP is upon early primary spermatocytes. This is also supported by mating data.

Animals↗
PubMed2002

Demineralized bone matrix and native bone morphogenetic protein in orthopaedic surgery.

The recognition that demineralized bone matrix could induce bone formation when placed in mammalian skeletal muscle led to preclinical studies of crude native insoluble bone morphogenetic protein and noncollagenous protein, followed by the clinical application of demineralized bone matrix, chemosterilized autolyzed antigen-extracted allogenic bone, and autolyzed antigen-extracted allogenic bone matrix gelatin. Cultural norms and regulatory agencies influence the availability of different demineralized bone matrix preparations in different parts of the world, but there is continued interest in the biologic structure of native insoluble bone morphogenetic protein and noncollagenous protein aggregates and the applied science of osteoinduction and osteoconduction in reconstructive orthopaedic surgery. Demineralized bone matrix is not widely available in Asia, but tissue processing facilities in the United States distribute demineralized bone matrix materials with different carriers, handling properties, and possibly osteoinductive potential. The purpose of the current study was to review the development and use of various preparations of demineralized bone matrix materials.

Animals↗
PubMed1976

Toxicity and health effects of selected organotin compounds: a review.

The toxicity of selected tin compounds is reviewed. Over the years, a variety of uses has been found for organic and inorganic tin compounds, as fungicides, as stablizers in plastics, moluscicides, and miticides; they have also been suggested as insect chemosterilants and for other industrial uses. Many of these products are unpalatable when mixed into diets and have been suggested as rodent repellents. Inhaling tin as dust or fumes may cause a benign pneumoconiosis in exposed workers. The organotin compounds can be divided into alkyltin and aryltin compounds. The trimethyl and triethyltin compounds are well absorbed from the gastrointestinal tract and are the most toxic in this group. Triethyltin particularly produces status spongiosus of the white matter of the central nervous system. Most of the other alkyl and aryl tin compounds are poorly absorbed from the gastrointestinal tract, and are less toxic when given orally than when given parentally. Only one compound, tricyclohexyltin hydroxide, is now registered by the Environmental Protection Agency as a miticide. This product produces skin irritation in rabbits. Studies should be conducted to determine whether it causes contact dermatitis in humans.

Animals↗
PubMed1976

Chemistry, biological activity, and uses of formamidine pesticides.

The formamidines, a relatively new group of acaricide-insecticides, are novel both in their range of biological activities and in their mode of action, which is presently unknown. This paper is a review of the historical development, properties, structures, uses, and chemistry of this group of pesticides, with particular emphasis on chlordimeform (Galecron or Fundal), N'-4-chloro-o-tolyl-N,N-dimethylformamidine, and amitraz, 1,3=di-(2,4-dimethylphenylimino)-2-methyl-2-azapropane. Their biological activity and uses are defined by their toxicity to spider mites, ticks, and certain insects, and they are particularly effective against juvenile and resistant forms of these organisms. A significant, but poorly understood feature of their field effectiveness is their breadth of toxic action which includes direct lethality, excitant-repellant behavioral effects, and chemosterilization. They are generally of low hazard for nontarget species with the significant exception of predaceous mites. Several aspects of the chemistry of these compounds are considered, including structure--activity relations, synthetic pathways, isomerism and configuration, and their chemical and environmental stability. A significant feature of the metabolism and toxicity of these agents is the possible activation of chlordimeform by N-demethylation in vivo. Strong evidence for this has been presented with the cattle tick, but recent results discussed here suggest that in other species, i.e., mice, German cockroaches or black cutworm eggs, N-demethylation is neither a strong activation nor a detoxication reaction.

Amidines↗
PubMedDate not supplied

Chemotherapy of filariasis--on the search of new agents effective on the reproductive system of female adult worms.

The design and synthesis of a series of alkyl 5(6)-substituted benzimidazole-2-carbamates (1-13), 7-chloro-4-(4-substituted phenyl)aminoquinolines (14-16), 1,2-dimethyl-3-methoxy-carbonyl-4,5-disubstituted pyrroles (17-19) and some compounds belonging to the class pimelonitrile (20), dihydroquinoline (21), pyridine (22), pyridoquinoline (23) and tetrahydro-pyrimidine (24) have been carried out as possible antifilarial agents. All these compounds have been evaluated for their activity against male and female adult worms of Litomosoides carinii in cotton rats. The effect of these compounds was also observed on the reproductive system (condition of developing microfilariae and their release from uterus) of adult female worms. In this study, three types of compounds were discovered: (a) those which showed activity on both the male and female adult worms and also had sterilizing effects on surviving adult females (1-3, 6-9, 13, 19), (b) those which only sterilized the adult females (14-16, 21, 24), and (c) those which had no effect on female reproduction but killed only adult worms (4, 5, 11, 12, 17, 18, 20, 22, 23). This tends to open up a new avenue in the chemotherapy of filariasis and the future scope of work on chemosterilization of adult females has been discussed.

Animals↗
PubMed1977

Effects of a juvenile hormone mimic on male and female gametogenesis of the mud-crab Rhithropanopeus harrisii (Gould) (Brachyura: Xanthidae).

1. Effects of ingestion and topical application of 1.30 ppm methoprene, an insect juvenile hormone (JH) mimic, include gametogenesis disorders in both male and female mud-crab Rhithropanopeus harrisii. 2. Progressive inhibition of vitellogenesis and stimulation of spermatogenesis take place after a short exposure time (12-15 days), whereas a longer period (between 30 to 45 days) promotes inhibition of both spermatogenesis and vitellogenesis. Such modifications demonstrate the chemosterilizing action of methoprene on crustaceans. 3. Stoppage of vitellogenesis is characterized by a blockage of oocytes at terminal previtellogenesis and proliferation of the follicle cells involved in vitellogenic oocyte lysis. Spermatogenic degeneration begins with the amalgam of spermatocyte clusters in meiotic prophase and pycnosis of gonia. 4. Analogies between these results and those obtained from experiments involving androgenic gland implantations or the consequences of their hyperfunctioning are discussed.

Animals↗
PubMed1979

Quinacrine hydrochloride. Review and mode of action of an antimalarial, used as an occlusive agent for transvaginal human sterilization.

Quinacrine hydrochloride, mainly used as an antimalarial, has been used as a nontoxic chemosterilant in a transvaginal procedure in the human female. Clinical experiments indicate that Quinacrine acts as a powerful obstructive agent exclusively on the epithelium of the intramural portion of the tube without alterating the histology of the endometrium. The precise mechanism of Quinacrine's obstructive action on the mucosa of the uterotubal junction is unknown. Its possible mode of action is binding to epithelial DNA thus forming a clot of granulomatous tissue, as Quinacrine is known to form adhesions when used in the control of neoplastic effusions. Zinc is known to inhibit Quinacrine-DNA binding. The human endometrium, rich in Zinc is unaffected by Quinacrine, whereas the tubal cornua, with little Zinc promote the obstruction by Quinacrine DNA bondage. The procedure is effective in 90 per cent of the cases with two instillations of Quinacrine. Further studies are essential to find agents that would potentiate the action of Quinacrine on the human Fallopian tube epithelium.

DNA↗
PubMed2000

Reconciliation of FDA and societal guidelines for endoscope reprocessing.

Chemical sterilants are used to high-level disinfect semicritical medical devices such as flexible endoscopes. For the chemosterilant to obtain a high level disinfection claim, The Food and Drug Administration requires demonstration of a 6-log reduction of myobacterial inoculum under worst case conditions (2% horse serum added to test sterilant). This testing requirement has led to label product claims of 45 minutes immersion times at 25 degrees C. Review of the scientific data suggests that at least an 8-log reduction in contamination with thorough instrument cleaning, followed by chemical disinfection for 20 minutes immersion at 20 degrees C will achieve high-level disinfection.

Disinfection↗
PubMed1992

Calvarial regeneration in primates with autolyzed antigen-extracted allogeneic bone.

The limited regenerative capacity of calvarial membranous bone provides an ideal system for investigation in the comparative physiology of bone regeneration. Cranial defects, 25 mm in diameter, were created in 24 adult male baboons (Papio ursinus). In each animal, defects were implanted with chemosterilized antigen-extracted, autolyzed allogeneic (AAA) bone, grafted with iliac corticocancellous grafts, or left ungrafted to monitor the spontaneous regeneration potential of the adult baboon calvaria. Antigen-extracted, autolyzed allogeneic bone implants were prepared from donor sub-adult baboon calvariae and processed so as to retain bone morphogenetic protein (BMP) in the bone matrix. Histomorphometric analysis of undecalcified sections (7-microns thick) prepared from specimens harvested at three, six, and nine months after surgery showed superior osteogenesis in AAA bone matrix implants, compared with autografts and untreated defects. The morphogenetic response was characterized by vascular invasion and mesenchymal cell aggregation after partial resorption and dissolution of the implanted matrix, followed by bone deposition at the calvarial interfaces, the pericranial and endocranial surfaces of the implants, and within the open diploic spaces of the implanted original AAA bone matrix. The superior osteogenesis in AAA bone implants appeared consistent with extensive osteoconductive invasion from the open diploic and endosteal spaces of the recipient calvariae. In addition, the finding of a delicate, trabecularlike bone, appositional to the central areas of the implanted matrix, suggests that AAA bone implants might also have acted as inductive substratum for bone differentiation.

Analysis of Variance↗
PubMed2006

Comparison of the efficacy of enrofloxacin, imidocarb, and oxytetracycline for clearance of persistent Anaplasma marginale infections in cattle.

This study compared enrofloxacin and imidocarb dipropionate treatments with an oxytetracycline regimen proposed by the World Organization for Animal Health for elimination of persistent Anaplasma marginale infections in cattle. The effect of therapy on competitive ELISA and polymerase chain reaction (PCR) reactivity was also assessed. Twelve A. marginale-infected carrier calves were randomly assigned to groups receiving either enrofloxacin (5 mg/kg IV q24h for 5 days), imidocarb (5 mg/kg IM twice, 7 days apart), or oxytetracycline (22 mg/kg IV q24h for 5 days). One calf infected with an Oklahoma isolate in the imidocarb group and one infected with a Virginia isolate in the oxytetracycline group failed to infect a splenectomized calf following blood subinoculation. Both became competitive ELISA negative by 44 days after treatment, but the imidocarb-treated calf remained PCR positive. None of the tested treatments reliably eliminated persistent A. marginale infections in all cattle. Furthermore, PCR was not a reliable means of determining the success of chemosterilization in calves.

Anaplasma marginale↗
PubMed1991

The contribution of sandfly control to leishmaniasis control.

Without doubt the single most important constraint on assessing the value of vector control in leishmaniasis control is the lack of well documented examples of intervention; information is usually anecdotal and therefore it is simply not possible to evaluate precisely the significance of sandfly control in disease control. Where the vector is peri-domestic, house spraying with residual insecticides has been employed, but this has usually been as a by-product of anti-malarial control (e.g. N.E.India). Increasing incidence of leishmaniasis following the cessation of mosquito control is cited as evidence of efficacy. However, habitat modification such as the destruction of mammal reservoirs and their burrows, has been effective in arid regions of the Middle East and Central Asia, and forest clearance in combination with insecticides in French Guiana. There have been several imaginative attempts at controlling sandflies by applying insecticides to non-domestic resting sites (eg. emergent trees in rain-forest; termite hills in Kenya and S. Ethiopia) but these have met with varying degrees of success. Fortunately there is little evidence of insecticide resistance. Therefore, there is still scope for exploring control methods based on either the systematic application of insecticides alone, the impregnation of nets or curtains, or even the use of insecticides or chemosterilants in conjunction with an attractant (eg. sugar or pheromones).

Animals↗