Search PubMed⌕ Search

Biomedical subjects

J D Williams

Publications and source records attributed to J D Williams.

At least 361 records · Page 20Linked to original sources
PubMed1981

Arterial plasma histamine after exercise in normal individuals an in patients with exercise-induced asthma.

1. Arterial plasma histamine concentrations, forced expiratory volume in 1.0 s (FEV1.0) and peak expiratory flow rate were determined in nine patients with exercise-induced asthma and in five control subjects before and after 8 min of cycle-ergometer exercise. 2. In the controls neither FEV1.0 nor peak expiratory flow rate fell by more than 5% in any individual during the 30 min postexercise period. The asthmatic patients all experienced a fall in FEV1.0 or peak expiratory flow rate, or both, of 15% or more in the period 5-20 min after completion of the exercise. 3. There was no difference between the control subjects and the asthmatic patients in the plasma histamine response to exercise. In both groups there was an insignificant rise of about 40% during exercise, although the initial levels were higher in the asthmatic patients. 4. The mean plasma histamine peak of the asthmatic patients preceded the mean maximal fall of FEV1.0 and peak expiratory flow rate by approximately 15 min. However, no positive correlation was found between rise in, or peak, plasma histamine levels and decrease in lung function. 5. Three non-atopic asthmatic patients had a significantly higher mean plasma histamine concentration during exercise than had the atopic subjects. 6. A strong positive correlation in asthmatic patients, and asthmatic and control subjects together was found between age and mean postexercise plasma histamine concentrations. 7. The results do not support a direct role for histamine in the production of exercise-induced asthma.

Adult↗
PubMed1981

In vitro activity of MK0787 (N-formimidoyl thienamycin) and other beta-lactam compounds against Bacteroides spp.

The susceptibilities of 82 strains of the Bacteroides fragilis group to eight beta-lactam compounds, lincomycin, and metronidazole were determined by using an agar dilution technique. MK0787 (N-formimidoyl thienamycin) was the most active compound, inhibiting all strains at a concentration of 1 microgram/ml. Metronidazole was the only other drug of similar activity. Of the beta-lactam compounds, cefoxitin and MK0787 showed uniform activity against all species, whereas most other compounds were relatively less active against Bacteroides distasonis and Bacteroides thetaiotaomicron than against B. fragilis and Bacteroides vulgatus. Using a well diffusion technique, we determined the relative stability of each beta-lactam compound to sonicated cultures of selected resistant strains. Whereas MK0787 was completely stable to inactivation--and with one exception, cefoxitin was also--ceftriaxone, cefotaxime, cephaloridine, and cefoperazone always showed some inactivation, often quite substantial. Moxalactam and ceftazidime were completely stable to some of the enzyme preparations.

Anti-Bacterial Agents↗
PubMed1981

Antidiuretic hormone excretion at high altitude.

Urinary excretion of electrolytes, creatinine, urea, and antidiuretic hormone--measured as arginine vasopressin (AVP) by radioimmunoassay--was investigated in eight Himalayan mountaineers during ascent on foot from 1900- 5400 m. Specimens were collected from each individual whenever urine was voided, preserved with 1% boric acid, and subsequently pooled to give samples representative of 24-h collections. AVP was found to be reasonably stable under simulated conditions of storage. In all subjects, the observed AVP excretion rates were mostly in the lower region of the normal range and there was generally no correlation with altitude, urine osmolality, electrolyte excretion, or occurrence of AMS symptoms--even in a fatal case of cerebral oedema. It is concluded that AVP does not play a primary role in the changes in fluid balance which accompany either acclimatization to high altitude or the onset of AMS.

Adult↗
PubMed1981

Adverse cardiovascular effects of oxytetracycline preparations and vehicles in intact awake calves.

Comparisons were made of cardiovascular effects in intact, awake, previously instrumented calves given the following oxytetracycline (OXY) preparations and components: polyvinylpyrrolidine vehicle (PVP), OXY HCl in PVP (OXY-PVP), OXY HCl (USP) in saline solution, propylene glycol, 77.8% (PG), propylene glycol vehicle (PGV), and OXY HCl in PGV (OXY-PGV). The 3 preparations containing PG caused significant increases in pulmonary arterial pressures and significant decreases in cardiac output and stroke volume. Aortic pressures were significantly decreased, as were heart rates. Both pulmonic and systemic resistances were significantly increased. There were no direct effects measured on left ventricular contractility. The aqueous OXY caused no significant changes. The PVP preparation and vehicle caused no changes in pulmonary pressures, pulmonary resistance, cardiac output, or stroke volume. Significant increases were observed in aortic pressure, heart rate, and systemic resistance. Left ventricular contractility was not changed. Seemingly, the PG-induced changes were a result of histamine release which did not appear to be dependent on prior sensitization of the calves.

Animals↗
PubMed1980

Evaluation of amikacin dosage regimes in the low and very low birthweight newborn.

The recommended neonatal dosage regime for amikacin of 15 mg/kg/day was found to be unsatisfactory in four neonates and a loading dose of 10 mg/kg did not improve levels in two further newborns with normal renal function. Fourteen neonates on 20 mg/kg/day regime achieved satisfactory levels; peak values were 21.5 +/- 4.5 microgram/ml and trough levels 3.34 +/- 2.05 microgram/ml. Peak time ranged from 17 to 60 minutes and varied with the dose given. The half-life was related to plasma creatinine, urea, post-natal age and weight. Thirteen neonates with pre-existing renal impairment were managed by alteration of dosage interval or quantity given. Side-effects were confined to eosinophilia in six infants, and no definite nephrotoxicity or gross eighth nerve damage was demonstrated.

Amikacin↗
PubMed1980

Interpretation of spectrophotometric absorbance values to define results of enzyme-linked immunosorbent assays.

An enzyme-linked immunosorbent assay method was used to classify bovine serum as positive, negative, or doubtful for antibodies to Brucella abortus. Spectrophotometric data from assays of 64 serologically positive and 32 serologically negative bovine sera were analyzed statistically to define the range of spectrophotometric absorbance values which classify sera. Statistical analysis indicated that absorbance values less than 0.08 should be considered negative and values greater than 0.14 should be considered positive, with intermediate values declared doubtful, and that the probability of erroneously classifying a positive serum as negative or a negative serum as positive is less than 0.005.

Animals↗
PubMed1980

Enzyme-linked immunosorbent assay for detecting antibodies to Brucella abortus in bovine milk and serum.

An enzyme-linked immunosorbent assay (ELISA) method was evaluated for the detection of antibodies to Brucella abortus in cows milk. Milk samples from seropositive or -negative cows were sed to determine the distribution of absorbance values to classify milk as ELISA positive or ELISA negative. Brucella abortus was isolated from milk samples from 10 (45%) of the 22 cows whose milk and serum were ELISA positive. The ELISA was evaluated and determined to be an appropriate method for detecting antibodies to B abortus in bovine milk.

Animals↗
PubMed1980

A study of the toxicity of imidocarb dipropionate in cattle.

The toxic effects of imidocarb dipropionate (3,3'-bis[2-imidazolin-2-yl] carbanilide dipropionate) were studied in calves injected twice intramuscularly with 0, 5, 10 or 20 mg/kg dosages. Transient, dosage dependent signs of toxicosis consisted of excessive salivation, serous nasal discharge, diarrhoea and dyspnoea. Elevations in blood urea nitrogen concentrations and serum glutamic oxalacetic transaminase activities were related to dosage and markedly increased at the high dosage. Renal hyperaemia, hepatomegaly, pulmonary congestion and oedema, hydrothorax, hydroperitoneum, hydropericardium and mortality occurred at the 20 mg/kg dosage. Microscopic lesions observed at the high dosage included acute severe renal tubular necrosis and focal hepatocellular necrosis. Injection site reactions varied from microscopic areas of necrotising myositis at the 5 mg/kg dosage to focal grossly visible areas of necrosis, encapsulated by granulation tissue and surrounded by fascial oedema at the 20 mg/kg dosage.

Animals↗
PubMed1979

Biotypes of Brucella abortus and their value in epidemiologic studies of infected cattle herds.

Four Texas cattle herds containing cows infected with either Brucella abortus biotype 1, 2, or 4 were studied to determine the probability of transmission of Brucella between adjacent cattle herds, the most probable means by which Brucella was introduced into the herds, and the relative frequency of strain 19 isolation from vaccinated cattle. A total of 1,935 cattle in the four herds were tested for brucellosis; 339 reactors were identified, and isolations of B abortus were made from 143. The biotype of B abortus was used to determine that purchased cattle or reentry of bred heifers into the herds was probably responsible for introducing B abortus and that the biotype was not readily transmitted to adjacent herds. Three (9%) of 32 B abortus isolations from adult-vaccinated cattle were strain 19. The data supported the hypothesis that biotypes can be useful in determining the source of B abortus for cattle and in differentiating field and vaccine strain infections in adult-vaccinated cattle.

Animals↗
PubMed1979

Another look at torsion of testis.

A retrospective review was done of all patients who had been discharged with a diagnosis of testicular torsion from 1967 to 1977. Multiple staff physicians were involved at the Milwaukee Children's Hospital. Incidence, age, presenting symptoms, and testicular survival were compared with previous reports in the literature. A 69 per cent testicular survival from torsion of the testis is a marked improvement over other series. Some suggestions for other diagnostic and therapeutic acids are mentioned.

Adolescent↗
PubMed1979

Transcatheter renal artery embolization in treatment of ureterocutaneous fistula.

We report a case of a critically ill patient who had a ureterocutaneous fistula develop after placement of a Dacron bypass graft from the aorta to the right popliteal artery and the left femoral artery. We describe a successful nonsurgical method to terminate renal function in this patient, who was a poor operative risk.

Aorta, Abdominal↗
PubMed1979

Comparison of serological methods for the detection of B. abortus antibodies in sera from vaccinated and non-vaccinated cattle.

A total of 4551 sera from 863 Strain 19 vaccinated and non-vaccinated adult cattle, independent of disease status, were tested by five serological methods to detect the presence of antibodies to B. abortus. Results from Standard Agglutination Tube (SAT), Buffered Brucella Antigen or card (CT), Complement Fixation (CF), Enzyme Linked Immunosorbent Assay (ELISA) and Rivanol (Riv) methods were compared. There was a 95% probability for agreement among CT negative sera, between serological methods, for all groups of vaccinated and non-vaccinated cattle. The agreement between tests with Riv Positive sera, excluding the calfhood and adult vaccinated group tested by the CF method, was 91-100%. The probability of a serum which was serologically negative by other methods being Riv negative was 98%. The usefulness of serological results from Riv (greater than or equal to 1/50) tests for classifying the reactor status of cattle are of doubtful supplemental value to confirm card test positive results. Vaccination history is an important consideration when evaluating serological data on cattle sera particularly from SAT and CF methods.

Agglutination Tests↗
PubMed1979

Relationships among different stages of Piagetian tasks and spatial relations in adolescents.

High school students aged 15 through 19 years (N = 116) were administered three Piagetian type tasks (conservation of weight, paper and pencil tests of concrete-operational reasoning and formal-operational reasoning) and a measure of spatial relations (the Revised Minnesota Paper Form Board Test). While a path analysis showed there were logically expected relationships among the tasks, neither sex differences nor age differences were found on any of the measures.

Adolescent↗