Detection of Human Rotavirus in Faeces from Diarrhoeic Calves in North-east Nigeria

Information on the epidemiology of rotavirus in any particular area is necessary for vaccine development against the disease caused by the virus. This study presents preliminary information on the prevalence of human rotavirus in diarrhoeic calves in North-east Nigeria. Faecal samples from 188 diarrhoeic calves in various farms in North-east Nigeria, obtained between November 1998 and February 1999, were analysed by ELISA for the presence of rotaviruses. A prevalence rate of 3.2% was recorded, with the virus being prevalent among calves aged 29–56 days (p<0.05). The implications of these findings are discussed with respect to the close association between the herdsmen and their animals and the sharing of a common source of drinking water in the predominantly livestock-producing communities of North-east Nigeria.     

Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores

Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500 degrees C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35 degrees to 80 degrees C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140 degrees C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.     

Hierarchically ordered oxides

Porous silica, niobia, and titania with three-dimensional structures patterned over multiple length scales were prepared by combining micromolding, polystyrene sphere templating, and cooperative assembly of inorganic sol-gel species with amphiphilic triblock copolymers. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from 10 nanometers to several micrometers. The respective ordered structures can be independently modified by choosing different mold patterns, latex spheres, and block copolymers. The examples presented demonstrate the compositional and structural diversities that are possible with this simple approach.     

Efficacy of an ivermectin and pyrantel pamoate combination against adult hookworm, Ancylostoma braziliense, in dogs

A chewable tablet incorporating ivermectin and pyrantel was tested in 12 Beagle dogs for efficacy against the adult hookworm, Ancylostoma braziliense. The dogs were administered infective larvae of A braziliense orally. Twenty-one days after infection the dogs were weighed and allocated randomly to receive either an oral treatment with ivermectin and pyrantel in a beef-based chewable tablet or no treatment. The chewable tablet was a commercially available product, which was made to deliver ivermectin at 6 μg/kg and pyrantel at 5.0 mg/kg to each dog. Seven days after treatment the dogs were euthanased, necropsied, and examined for adult hookworms. At necropsy, no adult A braziliense was observed in any of the 6 treated dogs and all 6 dogs that had been left untreated were infected with adult A braziliense (range, 48 to 161). It was concluded that this combination product is 100% efficacious against adult A braziliense.     

Development of a method for the identification, using the polymerase chain reaction, of Aspergillus fumigatus isolated from ostriches

Objective To develop a method for identifying DNA of Aspergillus fumigatus from ostriches, using the polymerase chain reaction (PCR). A fumigatus is the principal causative agent of avian aspergillosis.
Design A biochemical trial.
Sample population Twelve Aspergillus fumigatus isolates and three other Aspergillus species.
Procedure PCR primers that were based on the sequence of the alkaline protease gene from human isolates of A fumigatus were used.
Results We successfully tested the method on ostrich isolates from five states and showed that the test is specific for A fumigatus.
Conclusions In most cases the DNA sequence of A fumigatus isolates from ostriches is similar to that of human isolates. DNA sequences vary significantly among A fumigatus isolates, including those from affected ostriches in the same flock. The genetic variation may be used to trace aspergillus infections in ostrich flocks and determine if the disease is transmitted by contact with infected birds.     

Acute and Chronic Effects of a Contraceptive Compound RTI‐4587‐073(l) on Testicular Histology and Endocrine Function in Miniature Horse Stallions

The objective of this study was to evaluate acute endocrine effects as well as histological changes in testicular parenchyma induced by the contraceptive compound RTI‐4587‐073(l). Six miniature stallions were used in this experiment. The treatment group (n = 3) received one oral dose of 12.5 mg/kg of RTI‐4587‐073(l), and the control group (n = 3) received placebo only. The stallions' baseline parameters (semen, testicular dimensions, endocrine values) were collected and recorded for 5 weeks before treatment and for 6 weeks after treatment. Multiple blood samples were collected for endocrine analysis. Testicular biopsies were obtained before treatment, 1 day after treatment and every other week after treatment. Ultrasound exams were performed to monitor the dimensions of the stallions' testes. All stallions were castrated 6 weeks after treatment. Sperm numbers, motility and percentage of morphologically normal sperm decreased (p < 0.05), while the number of immature germ cells increased in ejaculates from treated animals (p < 0.05). Serum concentrations of inhibin and follicle‐stimulating hormone did not change. Testosterone concentrations initially transiently decreased (p < 0.05) after administration of RTI‐4587‐073(l), and increased several days later (p < 0.05). Testicular content of testosterone and estradiol 17‐β was lower in treated stallions than in control stallions on Day 1 after treatment (p < 0.05). Severe disorganization of the seminiferous tubules, significant loss of immature germ cells and complete depletion of elongated spermatids were observed in testicular biopsies obtained from treated stallions 1 day, 2 and 4 weeks after treatment. These changes were still present in the testicular samples taken from treated stallions after castration. The results of this study confirmed that RTI‐4587‐073(l) has antispermatogenic effects in stallions. Furthermore, we concluded that this compound causes acute sloughing of immature germ cells from the seminiferous tubules. RTI‐4587‐073(l) has significant but transient effects on Leydig cell function in stallions.