A pharmacokinetic study of midazolam in dogs: nasal drop vs. atomizer administration.

PURPOSE: The purpose of this investigation was to compare the pharmacokinetics of midazolam following intravenous, intranasal drop, and nasal-atomizer administration in beagle dogs. METHODS: Six animals weighing 9-13 kg were used in a repeated-measure design, group assignment based on route of drug administration. Midazolam (1.5 mg/kg) was administered with the delivery route based on group assignment. Blood samples were obtained at baseline and at 1, 3, 5, 7, 10, 15, 20, 30, and 45 min after administration. Cerebrospinal fluid samples (CSF) were obtained at 5 and 10 min after administration. Plasma and CSF concentrations of midazolam were determined by electron-capture gas-liquid chromatography. RESULTS: Comparison between groups and over time demonstrated that both nasal routes resulted in significantly higher CSF concentrations relative to corresponding plasma levels, and that nasal-atomizer administration produced significantly higher CSF concentrations compared to the drop approach.

Brainstem infarct with pharyngeal dysmotility and paralyzed vocal cord: management with a multidisciplinary approach.

An unusual case of right posterior brainstem infarction with isolated deficits of severe dysphagia and ataxia is presented. Neurological examination revealed dysfunction of the pharyngeal and laryngeal branches of cranial nerves IX, X, and a paralyzed right vocal cord. The patient was unable to swallow 1/4 teaspoon of applesauce. Modified barium swallow revealed extremely sluggish pharyngeal peristalsis and absent swallowing reflex. Percutaneous esophageal gastrostomy tube was inserted and an intensive dysphagia rehabilitation program was initiated. Pharyngeal-phase-oriented protocol was used. Results were significantly improved compensatory pharyngeal and laryngeal function with restoration of swallowing and no aspiration. This case illustrates successful management of dysphagia associated with brainstem infarction and the benefits of a coordinated multidisciplinary protocol.

Experimental borderline lepromatous leprosy with intraneural erythema nodosum leprosum in a mangabey monkey (Cercocebus atys).

A sooty mangabey monkey (Cercocebus atys) was inoculated with Mycobacterium leprae and developed borderline lepromatous leprosy and intraneural erythema nodosum leprosum. Previously studied mangabeys have developed only disseminated lepromatous leprosy without reactions. This case broadens the spectrum of leprosy seen in experimentally inoculated animals and further characterizes the nonhuman primate model of leprosy.

Histopathological changes in the eyes of mangabey monkeys with lepromatous leprosy.

Leprosy is the third leading cause of preventable blindness; however, little is known about the spread of infection to the eye. We have studied the eyes of three sooty managabey monkeys. Two were experimentally infected with Mycobacterium leprae; the third was not infected. In one of the infected animals there was histopathological evidence of lepromatous leprosy as evidenced by a chronic inflammatory infiltrate at the limbus, and detection of acid-fast bacilli in the corneal stroma, blood vessel walls, and corneal nerves. The latter were damaged as a result of the bacillary invasion. Electron microscopy revealed involvement and distortion of keratocytes with M. leprae and invasion of the corneal stroma by macrophages containing bacilli. Both infected animals showed focal collections of lymphocytes in the superficial stroma of the conjunctiva and in the ciliary body. This is the first report of the ocular manifestations of leprosy in any primate, including man, in which the duration of infection is known.

The effect of area postrema lesions on hemodynamic responses to systemic methionine-enkephalin in conscious dogs.

In the intact conscious dog, intravenous methionine-enkephalin (ME) increases heart rate and mean arterial blood pressure (MAP). These hemodynamic responses are produced at lower dosages when ME is injected into the vertebral artery, but not the carotid artery, suggesting that ME receptors are localized in the vertebrobasilar artery circulation. The area postrema (AP), a circumventricular organ devoid of a functional blood-brain barrier, represents a likely site for these receptors. We have tested the effects of chronic AP ablation upon hemodynamic responses to ME in conscious dogs. In three dogs with subtotal AP destruction, ME responses were preserved. However, in another dog with complete ablation of both the AP and the area subpostrema, ME responses were eliminated. These results indicate that total destruction of the AP, and perhaps of deeper structures as well, is necessary to abolish hemodynamic responses to ME.

A second sooty mangabey monkey with naturally acquired leprosy: first reported possible monkey-to-monkey transmission.

The existence of naturally acquired leprosy in a second sooty mangabey monkey has been documented. The disease has the clinical and histopathological characteristics of subpolar lepromatous leprosy (LLs), and microbiological studies thus far confirm the etiologic agent as Mycobacterium leprae. This mangabey had been housed in direct contact with the first mangabey in which naturally acquired leprosy was diagnosed in 1979. Clinical symptoms appeared in the second mangabey in 1986, almost 7 years after the appearance of skin lesions in the first monkey. It is likely that the second mangabey contracted leprosy from the first mangabey or that both animals contracted the disease by contact with an unknown common third source. This is the only known possible natural transmission of leprosy from monkey to monkey, and suggests that a potential zoonosis exists in wild monkeys that may serve as a reservoir for the disease in areas where human leprosy is endemic.

Multidrug chemotherapy of tuberculosis in rhesus monkeys.

Occurrence of tuberculosis caused by Mycobacterium bovis in a colony of rhesus monkeys allowed evaluation of a modern multidrug therapeutic regimen. Fifteen tuberculin positive rhesus monkeys with disseminated tuberculosis were evaluated for extent of disease by radiographic techniques, physical examination and laparotomy prior to treatment. Monkeys were divided into treatment groups of 3, 6 and 12 months duration and were treated once daily with isoniazid, rifampin and ethambutol. All animals survived their treatment course, had marked clinical improvement and rapid resolution of radiographically demonstrable lesions. Lesion regression evaluated by necropsy and histopathology correlated positively with length of treatment interval. Mycobacterium bovis was not isolated from any animal following treatment. Multidrug chemotherapy of tuberculosis was considered successful and practical in rhesus monkeys at the 12 month treatment interval. Chemotherapy may provide a reasonable alternative to destruction of valuable animals infected with tuberculosis.

Leprosy as a zoonosis: an update.

Naturally-acquired leprosy has been reported in nine-banded armadillos captured in the southern United States, a chimpanzee from Sierra Leone, and in two "sooty" mangabey monkeys from Nigeria. A significant prevalence of leprosy in wild armadillos establishes this animal as a reservoir of M. leprae, and exposure to armadillos has been implicated as a source of leprosy in humans. Current evidence suggests that leprosy is a zoonosis in certain nonhuman primate species. Control and eradication programs for leprosy should take into consideration the possible influence of extra-human sources of M. leprae, especially zoonotic leprosy.

Experimental leprosy in African green monkeys (Cercopithecus aethiops): a model for polyneuritic leprosy.

Three African green monkeys (Cercopithecus aethiops) were inoculated intravenously and intracutaneously with Mycobacterium leprae derived from a naturally infected mangabey monkey. All developed cutaneous lesions at inoculation sites. One developed disseminated cutaneous lesions, while the cutaneous lesions in the other two regressed and eventually disappeared. The animals were examined at necropsy five years after inoculation. All three had active leprosy infection in peripheral nerves with extensive inflammation and fibrosis. The disease histologically resembled borderline-lepromatous leprosy. These findings add a new dimension to animal models of leprosy.

Experimental leprosy in a rhesus monkey: necropsy findings.

A 6-month-old male rhesus monkey (Macaca mulatta) was inoculated intravenously and intracutaneously with Mycobacterium leprae obtained from a naturally infected mangabey monkey. The animal developed generalized lepromatous leprosy, and was killed for pathological examination 56 months after inoculation. Lesions were observed in the skin, nasal mucosa, peripheral nerves, and peripheral lymph nodes, with relative sparing of viscera. The monkey was carefully evaluated for the retrovirus STLV-III infection and was found negative. The rhesus monkey thus provides another animal model for the study of leprosy.

A primate model for acute and recurrent herpetic keratitis.

Twelve squirrel monkeys were inoculated in both eyes with the Rodanus strain of herpes simplex virus type 1 (HSV-1) and were examined for the presence of acute epithelial keratitis. All of the eyes developed dendritic keratitis within 72 hours after inoculation. The twelve monkeys plus two additional similarly infected monkeys were also examined for the presence of clinical recurrences of ocular herpes infections and spontaneous shedding of virus in their tears. Two of the eyes developed stromal disease, and 13 of the monkeys had at least one episode of recurrent clinical epithelial disease. Virus was isolated from two of the eyes with recurrent dendrites.

The lepromin test in rhesus monkeys.

The lepromin test was studied in rhesus monkeys. Six control monkeys which had not been inoculated with Mycobacterium leprae, six monkeys with experimentally induced leprosy, and nine monkeys which had been inoculated with M. leprae but had not developed leprosy were evaluated with 1X, 10X, and 15X lepromin A, with 1X and 10X lepromin M (mangabey monkey derived), with 1X and 25X purified inactivated M. leprae, and with an armadillo mock lepromin. We found that the lepromin test is useful in rhesus monkeys, but that a higher concentration of antigen than is used in humans is required to induce a response in monkeys. Control monkeys appear to be lepromin negative. Animals which have been inoculated and which develop lepromatous leprosy are also negative. Monkeys which are experimentally inoculated with M. leprae and do not develop leprosy become lepromin positive. Monkeys with indeterminate leprosy have reactions intermediate between lepromatous and resistant animals. No monkeys reacted to armadillo tissue. Our results indicate that 10X lepromin A is a useful preparation for the lepromin testing of rhesus monkeys.

In situ characterization of T lymphocyte subpopulations in leprosy in the mangabey monkey.

Leprosy in the mangabey monkey is an experimental model which is similar both clinically and histologically to human lepromatous leprosy. The immunopathology of these diseases was compared using monoclonal antibodies against T lymphocyte subpopulations in frozen tissue sections with an immunoperoxidase technique. In both mangabey and human lepromatous granulomas OKT4 (or Leu 3a) and Leu 2a cells were scattered among macrophages with greater numbers of Leu 2a as compared with OKT4 (or Leu 3a) cells. The results suggest that from an immunopathological standpoint experimental leprosy in mangabeys will provide a suitable model for the investigation of the pathogenesis of human lepromatous leprosy and for the evaluation of new antileprosy vaccines.

Transmissible lymphoma and simian acquired immunodeficiency syndrome in rhesus monkeys.

Four rhesus monkeys (Macaca mulatta) were inoculated with a homogenate of a cutaneous lepromatous leprosy lesion from a mangabey monkey (Cercocebus atys). One died of B-cell lymphoma, and another died of an immunodeficiency syndrome. Cell suspensions prepared from the tumor and spleen of the monkey with lymphoma induced lymphoma or an immunodeficiency syndrome when inoculated into additional young rhesus monkeys. The immunodeficiency syndrome was similar to simian acquired immunodeficiency syndrome and consisted of opportunistic infections, lymphoid hyperplasia or atrophy, wasting, and syncytial cell formation. Mitogen responses and percentages of T4- and T8-positive lymphocytes were normal until the animals were moribund. Lymphoblastoid cell lines became established in vitro from tumor cell suspensions. These cells were infected with a herpesvirus related to Epstein-Barr virus. In addition, a retrovirus morphologically similar to human T-cell lymphotrophic virus type III (HTLV-III) and simian T-lymphotrophic virus type III (STLV-III) was isolated from one of the lymphoblastoid cell lines (LCL). Type D retroviruses could not be demonstrated in the monkeys in the transmission study; however, a retrovirus similar to that in the LCL was isolated from 4 animals by coculture of peripheral blood lymphocytes with the human cell line H9. These results suggest that this retrovirus, STLV-III/Delta, may be associated with the immunodeficiency syndrome in these macaques and may be of mangabey origin.

Isolation of an HTLV-III-related retrovirus from macaques with simian AIDS and its possible origin in asymptomatic mangabeys.

Acquired immune deficiency syndrome (AIDS) has become a worldwide epidemic, so the development of vaccines and antiviral agents effective against the causative agent, human T-lymphotropic virus type III (HTLV-III), is vital. This work would be greatly simplified if a suitable animal model could be developed. Here we report the isolation of an HTLV-III-related retrovirus, STLV-III/Delta, from rhesus macaques (Macaca mulatta) with transmissible simian AIDS (SAIDS) and from asymptomatic sooty mangabeys (Cercocebus atys). SAIDS was initially diagnosed in several macaques previously inoculated with tissue homogenates of mangabey origin. Western blot analysis of both the mangabey and macaque sera demonstrated the presence of antibody cross-reactive primarily with the HTLV-III proteins p24 and p61. In a related experiment, analysis of these same sera revealed simian antibody to STLV-III/Delta proteins similar, but not identical, to those of HTLV-III with estimated relative molecular masses (Mrs) of 16,000 (16K), 26K, 35K, 45K, 60K and 110K. Infection of the mangabey, an African primate, with an HTLV-III-related virus may provide a clue to the origin of HTLV-III in humans. The apparent difference in susceptibility to SAIDS-like disease between infected macaques and mangabeys suggests that these species may respond differently to STLV-III infection.

Observations on early and late post-sporozoite tissue stages in primate malaria. IV. Pre-erythrocytic schizonts and/or hypnozoites of Chesson and North Korean strains of Plasmodium vivax in the chimpanzee.

In a continuing reexamination of plasmodial tissue stages within the context of the hypnozoite theory of malarial relapse, 2 strains of Plasmodium vivax with distinct and disparate relapse characteristics in humans were studied in chimpanzees. Following intravenous inoculation of massive numbers of salivary gland sporozoites, both the frequently relapsing Chesson strain and a North Korean strain characterized by predominantly delayed relapses exhibited relapse patterns and antimalarial sensitivity in the splenectomized chimpanzee essentially indistinguishable from those seen in humans. Examination of hepatic biopsies obtained at 7 and 10 days after infection revealed both pre-erythrocytic (pre-e) schizonts and hypnozoites in tissue obtained from the animal infected with the Chesson strain, but only rare hypnozoites (no pre-e schizonts) at 7 days in the animal infected with the North Korean strain. These findings, combined with the comparability of relapse behavior--which indicates the suitability of the chimpanzee as a model for the natural (human) host-parasite relationship--are essentially as predicted by the hypnozoite theory, despite the small numbers of tissue forms seen. Pre-erythrocytic schizogony of the Chesson strain in the liver was essentially indistinguishable from that of other strains studied, also underlining the suitability of this model system for tissue stage studies of P. vivax.

Experimental leprosy in the mangabey (Cercocebus atys): necropsy findings.

A mangabey monkey (Cercocebus atys) was inoculated intravenously and intracutaneously with acid-fast bacilli (AFB) from a mangabey with spontaneously acquired leprosy. It developed generalized lepromatous leprosy and died 46 months after inoculation. Necropsy revealed severe lepromatous infiltrates in the skin, nasal mucosa, peripheral nerves, and testicles. Internal organs were only minimally involved. The lesions seen at necropsy were very similar to those seen in untreated cases of human lepromatous leprosy. These findings further substantiate the mangabey monkey as a suitable animal model for the study of lepromatous leprosy.

Leprosy in a mangabey monkey--naturally acquired infection.

Naturally acquired leprosy was detected in an otherwise normal "sooty" mangabey monkey (Cercocebus atys). This animal was imported from West Africa in 1975 and developed clinical symptoms of leprosy in 1979. Histopathologic findings were those of subpolar-lepromatous to borderline-lepromatous leprosy in the Ridley-Jopling classification. The disease was progressive, with crippling neuropathic deformities of the hands and feet. The disease regressed under specific therapy. The etiologic agent was identified as Mycobacterium leprae by the following criteria: invasion of nerves of host, staining properties, electron microscopic findings, noncultivable on mycobacteriologic media, DOPA-oxidase positive, lepromin reactivity, infection patterns in mice and armadillos, sensitivity to sulfone, and DNA homology. We believe the animal acquired the disease from a patient with active leprosy. The mangabey monkey offers promise as a primate model for leprosy, and adds a third reported species to animals with naturally acquired leprosy.