Immunisation of cattle against theileriosis in Coast Province, Kenya: laboratory evaluation of a Theileria parva parva stabilate for use in 'infection and treatment' immunisation in the field.

Theileria parva parva Marikebuni stock, previously shown to give good protection to immunised cattle in Kilifi District, Coast Province of Kenya, was chosen for large scale immunisation in the district. A large sporozoite stabilate was prepared and evaluated for efficacy and safety in the 'infection and treatment' method, using a long or short acting formulation of oxytetracycline. Susceptible cattle were infected with selected doses of stabilate (10(0), 10(-1), 10(-1.

An ultrastructural study of an ascitic syndrome in young broilers reared at high altitude.

This study examined the ultrastructure of tissues from young broilers with an ascitic syndrome collected from a farm near Nairobi, Kenya which is located at an altitude of 1500 m. All organs (kidney, liver, heart, spleen and lungs) revealed more severe changes than those previously reported in age-matched birds during a low altitude study.

Improved characterization of Theileria parva isolates using the polymerase chain reaction and oligonucleotide probes.

Theileria parva DNA was purified from piroplasms isolated from cattle infected with 5 different East African isolates of the parasite, including the East Coast fever reference stock T. p. parva Muguga.

Frequency resolution in children.

The auditory frequency resolving ability of preschool children, school-aged children, and adults was assessed in a standard forced-choice masking experiment. Thresholds for pure-tone signals at 500 Hz, 2000 Hz, and 4000 Hz were obtained in two masking conditions. In one condition, the masker was a 4000-Hz-wide band of noise centered at the signal frequency; in the other, there was a notch in the noise spectrum, approximately one-half octave wide and 50 dB deep, centered at the signal frequency.

Temporal resolution in children.

The auditory temporal resolving power of young children was measured using an adaptive forced-choice psychophysical paradigm that was disguised as a video game. 20 children between 3 and 7 years of age and 5 adults were asked to detect the presence of a temporal gap in a burst of half-octave-band noise at band center frequencies of 400 and 2,000 Hz. The minimum detectable gap (gap threshold) was estimated adaptively in 20-trial runs.

Visceral leishmaniasis: resistance to reinfection in the liver following chemotherapy in the BALB/c mouse.

The ability of BALB/c mice to resist reinfection with Leishmania donovani following chemotherapy was studied. BALB/c mice, infected with L. donovani, were treated on Days 7 and 8 postinfection with free, niosomal, or liposomal sodium stibogluconate.

Characterization of buffalo-derived theilerial parasites with monoclonal antibodies and DNA probes.

The characteristics of intra-lymphocytic Theileria isolated from African buffalo and from cattle that were infected with buffalo-derived parasites were evaluated using anti-schizont monoclonal antibodies (mAbs) and DNA probes. Antigenic differences were revealed by the reactivities of 27 mAbs with the buffalo-derived parasites isolated from different animals. Antigenic diversity was also seen with Theileria-infected lymphoblastoid cell isolates taken from the lymph nodes and lambda gt11, showed specific hybridization to parasite DNA in Southern blots of restriction enzyme-digested, lymphoblastoid cells infected with buffalo-derived theilerial parasites.

Theileria parva: reappearance of schizonts in infected lymphoblastoid cells treated with parvaquone is dependent on interleukin 2-like growth factors.

Schizont-infected cell lines derived by in vitro infection of bovine T cell clones with the Muguga isolate of Theileria parva were treated for 72 hr with the theileriacidal drug, parvaquone, at a concentration of 10 micrograms/ml. This treatment completely eliminated schizonts from the recovered cells, which failed to undergo further proliferation and died. However, treated cells cultured with either bovine T cell growth factor or human recombinant interleukin 2 remained viable, underwent proliferation, and in many instances, schizonts reappeared.

Recoveries of whole-nerve AP thresholds, amplitudes and tuning curves in gerbils following noise exposure.

The recoveries of whole-nerve action potential (AP) thresholds, AP amplitudes and AP tuning curves in gerbils were monitored following two weeks of exposure to band-pass noise at 85 dBA. Recordings were made by means of electrodes chronically implanted in the subjects' bullas. The noise exposure caused threshold elevations in all of our subjects, with the greatest shifts occurring an octave or more above the 2 kHz upper cutoff frequency of the noise.

Visceral leishmaniasis: drug carrier system characteristics and the ability to clear parasites from the liver, spleen and bone marrow in Leishmania donovani infected BALB/c mice.

The efficacy of various sodium stibogluconate formulations against Leishmania donovani has been investigated using a BALB/c mouse model of visceral leishmaniasis. Only one therapy, multiple dosing with drug loaded sonicated vesicles, liposomes or niosomes, was found to be effective against parasites in the liver, spleen and bone marrow. Other treatments significantly reduced parasite liver burdens but either failed to effect spleen and bone marrow parasites, or were effective but toxic.

Phenotypic characterization of Theileria parva schizonts by two-dimensional gel electrophoresis.

Biosynthetically radiolabelled Theileria parva schizonts were purified from bovine lymphoblastoid cells and their proteins were analyzed by two-dimensional gel electrophoresis and autoradiography. The protein spot patterns of schizont proteins from three stocks of T. parva parva indicated that the phenotypic diversity among the stocks was minimal, with the Mariakani and Uganda stocks being identical and the Muguga stock showing only a few differences in minor spots.

Older Americans' access to oral health care.

To determine whether older Americans have difficulty obtaining access to dental care, we studied 7,265 adults nationwide. The objectives of this analysis are to: (1) determine the proportion of older Americans receiving dental services, (2) identify the types of services received, and (3) examine barriers to access to dental care in this population. Almost half of the respondents over the age of 60 reported a dental visit in the past year.

The therapeutic effect of sodium stibogluconate in BALB/c mice infected with Leishmania donovani is organ-dependent.

A study of the antileishmanial efficacy of sodium stibogluconate was carried out in BALB/c mice. The drug was administered to Leishmania donovani-infected animals on days 7 and 8 post-infection in one of three forms; free (40-50 mg Sbv Kg-1), liposomal, or niosomal (6.4-8.

Vesicular systems (niosomes and liposomes) for delivery of sodium stibogluconate in experimental murine visceral leishmaniasis.

Suppression of Leishmania donovani liver amastigotes by sodium stibogluconate has been determined in a murine model of experimental visceral leishmaniasis. Niosomal and liposomal drug formulations were equiactive and both increased drug efficacy by an order of magnitude compared with that of free drug. Niosomes containing 30 mol % cholesterol were prepared from three different non-ionic surfactants and no significant difference in activity was detected among the different drug-loaded niosomes.

Chemotherapy of East Coast fever: parvaquone treatment of Theileria parva parva at intervals after infection.

Groups of seven cattle were infected with Theileria parva stabilate and treated with parvaquone (20 mg kg-1 bodyweight) zero, four, eight, 12, 14 or 16 days after infection. Very early treatments resulted in a rapid recovery or no detectable parasitosis and some cattle were subsequently susceptible to homologous challenge. Treatments applied before extensive lymphoid or other organ damage had developed were successful and some cattle treated in advanced disease also recovered.

Gender trends in the career patterns of recent dental graduates.

The gender composition of U.S. dental schools has changed dramatically over the past 25 years.

Have dentists assimilated information about AIDS?

A random sample of 396 general dentists, oral surgeons, and periodontists in Los Angeles was interviewed in fall 1986. The purpose was to determine their experience in treating patients infected with HIV, factors associated with their knowledge about signs and symptoms of AIDS, and their sources of information regarding AIDS. The results showed that one-third of the dentists reported treating a known or suspected AIDS patient and that 56 percent indicated that they would not or could not treat patients with AIDS.

Biodegradable microspheres: polyacryl starch microparticles as a delivery system for the antileishmanial drug, sodium stibogluconate.

Liver parasite burdens of Leishmania donovani in the mouse have been determined after treatment with intravenous administration of sodium stibogluconate in the free or carrier form. The carrier form, in which the drug was covalently bound to polyacryl starch microparticles, was up to 100x more effective than the free form in this murine model of visceral leishmaniasis. Empty microparticles had no effect on liver parasite burdens and the enhanced in-vivo antileishmanial activity of the carrier form of the drug was apparently due to passive drug delivery to the infected liver.

Clinical trial of halofuginone lactate for the treatment of East Coast fever in Kenya.

A field trial was undertaken to test the efficacy of halofuginone lactate in the treatment of East Coast fever under farming conditions in Kenya. The drug was administered orally at a dose of 1.2 mg/kg bodyweight and treatment was repeated after 48 hours.