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Biomedical subjects

D Campbell

Publications and source records attributed to D Campbell.

At least 325 records · Page 18Linked to original sources
PubMed1984

Metastatic behavior of human tumor cell lines grown in the nude mouse.

The metastatic behavior of seven human tumor cell lines grown in young (3- to 4-week-old) nude mice was studied. Two cell lines were derived from malignant melanomas, one from a colon carcinoma, two from prostate adenocarcinomas, and two from renal adenocarcinomas. Many of the cell lines produced metastases after i.v. injection (experimental metastasis) and after s.c. transplantation (spontaneous metastasis) into young nude mice. The incidence of metastasis seemed dependent primarily on the biological characteristics of the individual tumor cell line. However, the incidence of metastasis of some tumor cell lines could be increased by isolation and establishment of variant sublines from secondary tumor deposits, by prolonged systemic administration of 17 beta-estradiol to suppress natural killer cell activity, and/or by use of an advantageous site of tumor implantation. Intrasplenic injection of tumor cells allowed the most dramatic overall expression of metastatic capacity in these cell lines, resulting in frequent and large metastases to liver, lungs, and the mesenteric, omental, and mediastinal lymph nodes.

Animals↗
PubMed1983

Effect of increased concentrations of carbon dioxide during halothane anaesthesia on liver blood flow and hepatic oxygen consumption.

The effects of hypercapnia (during halothane anaesthesia) on the hepatic circulation and hepatic oxygen consumption were investigated in anaesthetized greyhounds. The administration of 1% halothane alone caused significant decreases in both hepatic arterial and portal venous blood flows. Hepatic oxygen consumption did not change significantly. When carbon dioxide was added to the inspired gas mixture during the continued administration of halothane, hepatic arterial blood flow showed a further decrease (P less than 0.01), while portal venous flow increased markedly. This resulted in an overall increase in total liver blood flow. Hepatic oxygen supply increased also. However, hepatic oxygen consumption increased during the periods of hypercapnia. Thus, although the hypercapnia increased the oxygen supply to the liver, there was no improvement in the supply: demand ratio.

Anesthesia, Inhalation↗
PubMed1983

Dietary NaCl loads promote calciuria and bone loss in adult oophorectomized rats consuming a low calcium diet.

This study was undertaken to determine whether dietary supplements of NaCl would exaggerate osteopenia in oophorectomized (OOPX) rats consuming a low calcium (0.01% Ca) diet. Thirty 300 g OOPX rats with 45Ca-labeled bones were studied. Animals in group 1 were killed at the start of the experiment, whereas those in groups 2 and 3 were fed a low calcium diet for 2 months. Group 3 rats received NaCl (8 g/100 g diet). Salt increased the urinary excretion of sodium, calcium, phosphate, cyclic AMP, 45Ca and hydroxyproline but did not augment fecal excretion of calcium or 45Ca. Salt caused bone loss. The femora of NaCl-treated rats contained less 45Ca, less calcium, less phosphate and less mineral ash than those of rats killed at the start of the experiment. It is suggested that in OOPX rats consuming a low calcium diet, increased NaCl intake causes decreased renal tubular reabsorption of calcium and consequently lowered plasma Ca++. This results in stimulation of parathyroid hormone secretion and thus increased bone resorption. We conclude that NaCl supplements exacerbate osteopenia in adult OOPX rats consuming a low calcium diet. The effects of high dietary salt intakes on bone loss in postmenopausal women deserve further study.

Animals↗
PubMed1983

Respiratory injury in the burned patient. The role of flexible bronchoscopy.

The purpose of the study was to investigate the role of flexible bronchoscopy in the management of patients admitted to a busy Regional burns unit, with particular reference to possible smoke inhalation injury. The basic procedure employed was that used in routine bronchoscopy for the diagnosis of bronchial carcinoma, with modification of the premedication required in view of the shorter duration of the technique and the lack of a requirement for bronchial biopsy. We have found the procedure easy to perform, well tolerated by the patients and not associated with any complications. It provides additional information not otherwise available, which can influence the subsequent management of the patient. An experienced bronchoscopist and additional personnel skilled in resuscitation techniques are required. It should be performed in patients with clear evidence of smoke inhalation injury and in particular with facial burns in order to visualise the extent of airway injury, remove debris and give some indication of the likelihood of subsequent complications such as acute upper airways obstruction.

Adult↗
PubMed1983

Energy balance and nitrogen balance in growing low birthweight infants fed human milk or formula.

Energy and nitrogen balances were measured in growing low birthweight infants fed either mother's expressed breast milk or a 20 kcal per ounce formula to determine whether or not there were differences between the two dietary groups in (1) the partition of energy among excretion, expenditure, and storage and (2) the relation of energy storage and nitrogen retention to weight gain. There were no significant differences between the human milk fed infants and formula fed infants in gross energy intake, metabolizable energy intake, nitrogen intake, or nitrogen retention. Energy expenditure was significantly lower in the human milk fed infants than in formula fed infants (221 kJ/(kg. day) and 244 kJ/(kg. day), respectively). There was no difference in mean energy storage between the two groups. Although weight gains were similar in both dietary groups, the ratio of energy storage to weight gain was significantly greater in infants fed with human milk (15.3 kJ/g, S.D. 2.0) than in infants fed formula (13.2 kJ/g S.D. 1.8). There was no significant difference between the two groups in the ratio of nitrogen stored to weight gain.

Body Weight↗
PubMed1983

A study of dermatitis in trona miners and millers.

Trona (sodium sesquicarbonate) is mined from an underground deposit in Wyoming and processed for use in the manufacture of glass, paper, and detergents, and in chemical applications. Trona dust is alkaline (pH 10.5) and may have an irritant effect on the respiratory airways, mucous membranes, and the skin. One hundred forty-two underground miners and 88 surface workers from one trona facility participated voluntarily in an epidemiologic and clinical study. Their mean age was 37.6 and their mean working period, 10.0 years. One half of the study participants complained of skin symptoms; dermatologic symptoms increased from twofold to fifteenfold after the subjects began trona mining. Trona dermatitis consists of pruritic, erythematous, raised, dry, and fissured lesions commonly affecting the hands, arms, and legs. A dose-response relationship was observed among underground workers. Patch testing with 10% aqueous trona and sodium carbonate was negative, suggesting that the dermatitis was primarily irritant in nature.

Adult↗
PubMed1982

Use of microcomputers for self-assessment and continuing education in anaesthesia.

The suitability of computer-assisted self-assessment was evaluated as a means of quality assurance in anaesthesia. Altogether 202 anaesthetists participated in four trials of the method. Analyses of their performance in a self-assessment programme dealing with obstetric anaesthesia showed significant differences in the levels of knowledge of anaesthetists practising for different numbers of years. The acceptability of computer-assisted self-assessment ranged from 91% to 100% for the four trials. Similar programs have been shown to be of value in medical education and thus computer-assisted self-assessment appears to fulfil simultaneously the functions of self-assessment and continuing education. The criteria for a method of quality assurance are met.

Anesthesiology↗
PubMed1982

Effect of stress, meal and neostigmine on rectosigmoid electrical control activity (ECA) in normals and in irritable bowel syndrome patients.

An intraluminal probe with two sets of bipolar electrodes (4 cm apart) was used to record electrical control activity (ECA) from the rectosigmoid of 17 normal subjects and 16 IBS patients in the resting state, during neutral and stressful interviews, and after a meal or neostigmine. Fast Fourier transform method was used for the frequency analysis of ECA. The ECA was present at all times in both the groups but was variable in frequency and amplitude and was phase-unlocked during all recording periods. Up to four frequency components were observed in the lower frequency range (LFR) of 2.0-9.0 c/min and up to two in the higher frequency range (HFR) of 9.0-13.0 c/min during all recording periods. The frequency and organization of ECA were not significantly different between the normal and the IBS groups in the resting state. Neutral and stressful interviews did not significantly affect the mean ECA frequency in either of the groups but the mean ECA frequency of the dominant frequency component in LFR was lower in IBS patients than in the normal subjects during the stressful interview. Meal and neostigmine did not significantly affect the ECA frequency or its organization in either of the groups. It appears from this study that alternations in colonic ECA may not form the basis of motility disorder in irritable bowel syndrome.

Adolescent↗
PubMed1982

Genetic composition and virulence of influenza virus: differences in facets of virulence in ferrets between two pairs of recombinants with RNA segments of the same parental origin.

Facets of virulence for ferrets of 16 recombinant clones of two parent viruses A/Finland/4/74 (H3N2) and A/Okuda/57 (H2N2) were determined and viewed in relation to their genetic composition. Of the five pairs of recombinant clones with RNA segments of the same parental origin, differences in facets of virulence were detected between members of two of the pairs. One pair differed in ability to produce fever, and another pair in ability to infect the lower respiratory tract. Subsequent analyses indicated slight differences in two genes of the first pair of viruses. Of all the recombinant clones examined the three that derived their surface antigens from the attenuated parent (A/Okuda) were less virulent than the 13 which possessed the surface antigens of the virulent parent (A/Finland). The virulence of the latter clones tended to decrease as the number of RNA segments that were derived from A/Okuda increased.

Animals↗
PubMed1982

Effects of nitrous oxide on liver haemodynamics and oxygen consumption in the greyhound.

The effects of increasing concentrations of nitrous oxide 30, 50 and 70% on the hepatic circulation and hepatic oxygen consumption were investigated in seven normocapnic greyhounds. Hepatic arterial and portal venous blood flows were measured continuously using electromagnetic flow probes, and mean arterial pressure and cardiac output monitored. The administration of nitrous oxide caused linear decreases in hepatic arterial, portal venous and total liver blood flows. Increases in mean arterial pressure, hepatic arterial resistance and mesenteric vascular resistance were noted. There were no significant changes in hepatic oxygen consumption. It is suggested that the decrease in liver blood flow may result from alpha-adrenoceptor stimulation.

Animals↗
PubMed1982

Characterization of nontypable Streptococcus pneumoniae-like organisms isolated from outbreaks of conjunctivitis.

From January through June 1980 seven colleges and universities in various parts of New York State (NYS) reported outbreaks of conjunctivitis affecting at least 1,500 students of both sexes. Of the 125 conjunctival swabs tested in our laboratory, organisms identified as nontypable Streptococcus pneumoniae were isolated in pure culture from 24% and in combination with other organisms from 22%. Although bile-soluble and susceptible to optochin, the isolates had a dry-colony appearance and no typable capsule with the Neufeld capsular-swelling test. Mouse passage of four representative NYS isolates did not stimulate production of a typable capsule. We subsequently chose to refer to these isolates as S. pneumoniae-like organisms. Of primary importance to our study, all NYS isolates tested were similar in biochemical and immunological reactions, antibiotic susceptibility, and virulence in mice. Of 18 strains referred to us from three other outbreaks (California, 1980; NYS, 1981; Illinois, 1981), four of the six tested biochemically gave the same biochemical reactions as the four NYS isolates, and 16 of the 18 tested immunologically reacted strongly with antisera produced against those four isolates, showing line(s) of identity with each other and with the NYS isolates.

Animals↗