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Biomedical subjects

R H Jones

Publications and source records attributed to R H Jones.

At least 343 records · Page 19Linked to original sources
PubMed1977

Bluetongue in cattle: effects of vector-transmitted bluetongue virus on calves previously infected in utero.

Three of 7 principal calves, after a challenge of immunity exposure by bites of bluetongue (BT) virus-infected Culicoides variipennis, became latently infected with BT virus. These calves were born to heifers infected with the homologous virus by bites of C variipennis at 60 or 120 days' gestation. Latent BT virus infection was detected by isolation of BT virus from washed erythrocyte samples obtained from the calves at 57, 100 to 102, 200 to 202, 300 to 302, and 400 to 402 days after challenge of immunity and from 1 of the calves over 5 years after challenge of immunity. The 3 latently infected calves were healthy; 2 were immunologically competent and 1 was immunologically incompetent to develop detectable BT virus antibodies in their blood. Bluetongue virus infection was detected (by viral isolation) in 2 other principal calves during the challenge of immunity, but they were not considered latently infected. The latter 2 calves were immunologically incompetent to develop detectable BT virus antibodies.

Animals↗
PubMed1977

Bluetongue in cattle: repeated exposure of two immunologically tolerant calves to bluetongue virus by vector bites.

A heifer and steer that were immunologically tolerant to bluetongue (BT) virus became immunologically competent after repeated exposures by bites of BT virus-infected Culicoides variipennis. Immunologic tolerance ended in the heifer at 25 months of age, after the 2nd exposure to the virus, and in the steer at 22 months, after the 4th exposure. High hemic concentrations of BT virus were detected in both animals after they became immunologically competent, but neither developed an overt BT clinical response. The steer died suddenly and extensive pathologic changes were observed at necropsy.

Animals↗
PubMed1977

Studies on the relationship between the molecular structure and the catabolism of insulin.

The catabolism of insulins modified at the A1, B1 or B29 positions or containing a synthetic crosslink between the A1 and B29 positions has been studied in vivo and in vitro. The metabolic clearance rates (MCR) of insulin, proinsulin and chemically modified insulins have been measured by a priming-dose constant infusion technique in greyhounds. Insulins modified at A1 and B29, particularly the crosslinked materials, had markedly lowered MCR's whilst B1 analogues did not differ from insulin. Proinsulin and the A1-B29 crosslinked materials showed a markedly lowered degradability by glutathione-insulin transhydrogenase.

Animals↗
PubMed1977

Regional pulmonary function during experimental unilateral pneumothorax in the awake state.

This study examines changes in regional pulmonary function during unilateral pneumothorax, immediately after, and 2 hours following re-expansion in awake dogs. Respiratory rate, tidal volume, physiologic dead space, arterial blood gases, and pulmonary shunt fraction were determined at each stage. Cardiac output (thermodilution), vascular pressures, and regional ventilation and perfusion (133Xe scans) were also measured. Chest roentgenogram confirmed the presence of UP. Respiratory rate increased 124 percent (p less than 0.01) during UP while alveolar ventilation remained unchanged. Pulmonary shunt fraction rose 93 percent (p less than 0.01) during UP, causing PaO2 to fall from 86 to 51 mm. Hg (p less than 0.01). PaCO2, pH, and cardiac output were not altered by UP. UP caused a relative underventilation of the collapsed lung (V/Q = 0.73 (p less than 0.01)) and an overventilation of the contralateral lung (V/Q = 1.74) (p less than 0.01). Immediately after re-expansion of the collapsed lung, all the above changes reverted to the control values. All variables remained unchanged 2 hours following complete re-expansion.

Animals↗
PubMed1976

Biological properties of chemically modified insulins. I. Biological activity of proinsulin and insulin modified at A1-glycine and B29-lysine.

Beef insulin, pork proinsulin and four derivatives of beef insulin modified at the A1-B29 site on the molecular surface have been studied. Three derivatives had a synthetic crosslink between the A and B chains. Previous studies with these materials [2, 3 and 5] had demonstrated in vivo bioactivities which were much higher than those displayed in vitro. This paper reports experiments which explain this discrepancy. The analogues were administered at equimolar rates to anaesthetised greyhounds by a priming-dose constant infusion technique and the plasma concentrations achieved were estimated by radioimmunoassay. Proinsulin and the modified insulins were metabolised more slowly than insulin. Biopotency values, which related fall in plasma glucose concentration to the total administered dose of analogue, agreed broadly with published results of conventional in vivo bioassays. On the other hand, calculation of potency in relation to the serum concentration of analogue actually achieved, yielded results which agreed more closely with in vitro assay data. We conclude that for these analogues, reported discrepancies between in vitro and in vivo biopotencies can be largely explained by the different rates at which these materials are metabolised.

Adipose Tissue↗
PubMed1976

Pulmonary embolism.

Pulmonary embolism is a common and often fatal postoperative complication. Dyspnea is the most common clinical manifestation in pulmonary embolism, and other signs are frequently inconsistent and often vague. The chest film and electrocardiogram may be helpful in excluding other cardiorespiratory diseases but they are frequently unreliable in establishing an objective diagnosis of pulmonary embolism. Documentation of a decreased arterial saturation provides suggestive evidence of pulmonary embolism. Lung scanning is a safe, sensitive procedure for the initial evaluation of symtoms suggestive of pulmonary embolism, and pulmonary arteriography may be necessary to confirm the diagnosis in certain patients. Anticoagulation is effective in the prevention and treatment of pulmonary embolism and proves successful in the vast majority of patients. Emboli that are not fatal gradually resolve in the pulmonary circulation. Vena caval interruption is occasionally beneficial in selected patients, especially those with septic emboli and cor pulmonale, but should only be performed when the indications are quite clear. Under certain selected circumstances pulmonary embolectomy may be indicated. Patients with massive embolism occluding more than one-half of the pulmonary arterial system and prooducing a markedly elevated pulmonary arterial pressure and severe hypoxemia may die in acute right heart failure. Intractable shock unresponsive to aggressive medical therapy in these patients represents an indication for pulmonary embolectomy. The hazards of these surgical procedures demand that a definite diagnosis of pulmonary embolism be made and a systematic approach to the diagnosis and treatment should be followed in all patients with the disorder.

Adult↗
PubMed1976

Demonstration of extracellular material at the surface of pathogenic T. pallidum cells.

Pathogenic T. pallidum cells possess and extracellular layer when observed in vivo and in vitro after exposure to ruthenium-red. The extracellular layer is partially removed from a pre-fixed cell by repeated washing in vitro. Non-pathogenic treponemes examined in this study do not possess an extracellular layer. It is hoped that the data presented herein will cause our colleagues to take another look at the methods and techniques used for preparing pathogenic T. pallidum cells for practical end-point objectives.

Animals↗
PubMed1976

Growth and subculture of pathogenic T. pallidum (Nichols strain) in BHK-21 cultured tissue cells.

The growth and nine subcultivations of the experimental Nichols strain of pathogenic Treponema pallidum were successfully accomplished in cultured baby hamster kidney tissue cells (BHK-21) using serum-free media. The number (motile and non-motile cells occurring extracellulary) of cell generations generally increased with each subcultivation, the largest increases (greater than 3-0) occurring in subcultures 4, 5, 7, 8, and 9. Also, the number of motile cells decreased with each subcultivation. Virulent organisms were demonstrated in subcultures 1, 4, 5, 7, and 8, and their numbers estimated with the use of standards established by the animal inoculation titration of counted numbers of organisms freshly harvested from experimental infections; the estimated number of virulent organisms was higher than or equal to the counted cultivated treponemes injected, which may be attributable to uncounted virulent spirochaetes occurring intracellularly.

Animals↗
PubMed1976

Experimental syphilis vaccines in rabbits. I. Differential protection with an adjuvant spectrum.

This study shows that 1 per cent. glutaraldehyde fixation of unwashed Treponema pallidum, Nichols pathogen, preserves the integrity of the outer envelope as well as the ruthenium-red (RR) staining extracellular slime layer. Since other researchers wash their treponemal suspensions before preparing their vaccines, it is likely that the vaccine preparations used in this study contain antigens not tested elsewhere. In an attempt to eliminate the requirement of large numbers of injections to achieve any protection, the rabbits in this study were injected with glutaraldehyde-fixed T. pallidum (GFTP) only once, with or without one of a spectrum of adjuvants, and 5 months later were challenged intradermally or intratesticularly with freshly harvested pathogenic treponemes. Data of time of lesion appearance and severity of lesions reveal a differential protective effect of the various vaccine preparations when compared to the response of non-vaccinated controls. Vaccines which included phytohaemagglutinin (PHA) or alumina C gel (ALC) as adjuvants provided some degree of protection, whereas vaccines which contained the adjuvants incomplete Freund's, zymosan, complete Freund's, polyadenylic-polyuridylic acid, or no adjuvant at all produced enhanced infections. The differential protection data indicate that various portions of the immune mechanism are either suppressed or are not stimulated by T. pallidum antigens alone, but can be made to respond with a minimum of vaccine injections.

Adjuvants, Immunologic↗
PubMed1976

The effects of glucosamine derivatives on the growth of cultivable Treponema.

The effects of glucosamine and its derivatives on the growth of Treponema phagedenis biotypes reiter and kazan 5 were studied to determine if these agents could act as growth stimulants for organisms of the genus Treptonema. Growth studies on the cultivable treponemes were conducted in culture tubes containing glucosamine, glucosamine derivatives, and (or) glucose and galactose in serum-based media. Glucosamine and N-phenylacetylglucosamine were definitely inhibitory to growth at the concentrations studied. N-acetylglucosamine (NAG) produced mixed effects.

Acetylglucosamine↗
PubMed1976

The effect of atropine on the insulin release caused by oral and intravenous glucose in human subjects.

Oral and intravenous glucose tolerance tests were performed on normal fasting subjects, with and without atropine. Insulin release after oral glucose was significantly diminished by atropine, and this effect could not be ascribed to the drug delaying glucose absorption. However, insulin release brought about by intravenous glucose was not altered by atropine. Possible interpretations of these results are discussed.

Administration, Oral↗
PubMed1976

Arbovirus surveillance in six states during 1972.

A virus surveillance project was established and maintained during 1972 along 10 major river drainages in six states. Mosquitoes, biting flies, and blood specimens from sentinel equines were collected during 83 field trip visits to 141 arthropod collecting sites and 22 sentinel locations from April into December 1972. There were 173,074 mosquitoes tested and 303 arboviruses isolated from 11 of 41 species. From 13,388 biting flies tested, 8 arbovirus isolations were obtained in 1 of 5 species. There was no isolation of Venezuelan equine encephalitis (VEE) virus. Western equine encephalitis (WEE) virus isolates were the most numerous and were followed by Turlock, St. Louis encephalitis, Hart Park, California encephalitis, and Bunyamwera (BUN) group viruses. The first isolation of WEE from the mosquito Cullex (Mel). erraticus is reported, as is the extension of the ranges for Buttonwillow virus from California to New Mexico and Texas. Also a single isolation of the BUN group from Culicoides variipennis extends the range of this virus-vector relationship from California to Texas. New distribution records for mosquito species previously unreported for Arizona, Louisana, New Mexico, and Oklahoma are reported. The sentinel burros detected WEE serologic conversions at two sites in New Mexico and at one in Texas. The surveillance project provided state and federal officials with current information on the status of arbovirus activity, including the absence of VEE activity during 1972, and it demonstrated the existence of the potential for WEE epizootics and epidemics throughout a wide geographic area of the Western United States.

Animals↗
PubMed1976

The diagnosis of pulmonary embolism.

Objective documentation of pulmonary embolism is an essential prerequisite for appropriate treatment (Figure 7). A chest film, as well as measurement of arterial blood gases, should be obtained immediately, and if the lung fields are essentially normal, a lung scan should then be performed. If the scan shows a definite perfusion defect characteristic of embolism, this provides sufficient evidence to establish a diagnosis of pulmonary embolism. The presence of hypoxemia with a low arterial pO2, further confirms the suspicion of a ventilation-perfusion abnormality, and anticoagulant therapy with heparin should be initiated immediately. Should the chest film show abnormalities in the same anatomic areas in which perfusion defects are present on the scan, further investigation by pulmonary arteriography is required to substantiate the diagnosis. The use of pulmonary angiography for documentation of pulmonary embolism is also indicated at the outset when certain specific disorders that confuse scan interpretation are also present-chronic obstructive lung disease, emphysema, asthma, congestive cardiac failure. Assessment of the arterial blood oxygenation simultaneously with the estimated occlusion and the hemodynamic data can be used as a prognostic index as therapy progresses.

Blood Gas Analysis↗
PubMed1976

Serial cyclic transmission of bluetongue virus in sheep and Culicoides variipennis.

Bluetongue virus (strain 62-45S) was transmitted from sheep to sheep throughout a year by vector bites. A colonized population (SONORA strain, 000 line) of the biological vector Culicoides variipennis (Coquilllett) was used. Fifteen serial cyclic transmissions covered a period of 13 months from October through November of the following year. The mean infection rate of the biting gnats was 37 percent. The clinical response to bluetongue virus was significantly more severe in sheep infected by vector bites than in those inoculated with the virus at the same sheep-serial passage level. A second corroborative serial transmission was conducted for 7 months from June through December. The mean infection rate of the vector was 27%.

Animals↗