Search PubMed⌕ Search

Biomedical subjects

J Robertson

Publications and source records attributed to J Robertson.

At least 199 records · Page 11Linked to original sources
PubMed1987

Combined flow and absorption DNA measurements of [3H]TdR-labelled tumour cells. I. Studies of MCa-11 cells grown as tumours in vivo and as exponential cultures in vitro.

Flow cytometry of cellular DNA content provides rapid estimates of DNA distributions, i.e. the proportions of cells in the different phases of the cell cycle. Measurements of DNA alone, however, yield no kinetic information and can make it difficult to resolve the cell cycle distributions of normal and transformed cells present in tumour biopsy specimens. The use of absorption cytophotometry of the Feulgen DNA content and [3H]TdR labelling of the same nuclei provides objective criteria to distinguish the ranges of DNA content for G0/G1, S, and G2/M cells. We now report on a study in which we combined flow and absorption cytometry to resolve the cell cycle distributions of host and tumour cells present in biopsy specimens of MCa-11 mouse mammary tumours labelled in vivo for 0.5 hr with [3H]TdR. A similar analysis of exponential monolayer cultures, labelled for 5 min with [3H]TdR under pulse-chase conditions, revealed a highly synchronous traversal of almost all cells through the different phases of the cell cycle. Combination of the flow and absorption methods also allowed us to detect G2 tumour cells in vivo and a minor tumour stem-line in vitro, to show that these two techniques are complementary and yield new information when they are combined.

Absorption↗
PubMed1987

Duration of antithyroid action of methimazole estimated with an intravenous perchlorate discharge test.

We have used a method based on a perchlorate discharge test to estimate the duration of antithyroid effect of two doses of methimazole (MMI). Six patients with diffuse toxic goitre took 5 mg MMI twice daily and six took 20 mg twice daily over the study period of 12 weeks. Biochemical control of hyperthyroidism was achieved in all patients and thyroid hormone supplementation was required by all of the patients in the higher dose group to avoid hypothyroidism. Discharge of radioiodine from the thyroid by perchlorate diminished in both groups with time after MMI. After 5 mg MMI, perchlorate discharge as a percentage of the 30-min uptake (mean +/- SD), was 81.7 +/- 3.3% at 2.2 h, 69.3 +/- 18.9% at 5.9 h, 22.6-23.4% at 13.4 h and 2.7-6.7% at 25.1 h. After 20 mg MMI, the discharge was 92.5 +/- 1.9% at 2.2 h, 84.3 +/- 8.8% at 6.3 h, 64.8 +/- 24.1% at 13.3 h and 26.9-29.4% at 25.1 h. Only four patients (one in the lower dose group) showed a detectable discharge at 25 h and one of the patients treated with the lower dose showed no discharge at 13 h. These estimates of the effect of MMI on thyroidal iodide organification are not in keeping with published thyroidal MMI concentrations which do not show a fall between 3-6 h and 17-20 h after carbimazole. The explanation for this disparity is not clear but may be based on a redistribution of thioureylenes within the thyroid with time after dosage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Dopamine receptor-mediated spinal antinociception in the normal and haloperidol pretreated rat: effects of sulpiride and SCH 23390.

Nociceptive tail flick latencies (TFL) were recorded in response to noxious thermal stimuli applied to lightly anaesthetized rats. The effects of intrathecally administered dopamine receptor agonists alone and combined with dopamine receptor antagonists were examined upon the TFL. Experiments were repeated on animals made supersensitive to dopamine following withdrawal from 28 day administration of haloperidol. In untreated animals the D2-receptor agonist LY 171555 and apomorphine produced an increase in TFL. In contrast, the Di-receptor agonist SKF 38393 had no significant effect on TFL. TFL. Following haloperidol-induced dopamine-supersensitivity, SKF 38393 produced an increase in TFL. In contrast, LY171555 and apomorphine had minimal effects on TFL in this preparation. In animals not treated with haloperidol, the dopamine receptor antagonists SCH 23390 and (+/-)-sulpiride both blocked the increase in TFL produced by the D2-agonists. SCH23390 and (+/-)-sulpiride also blocked the increase in TFL produced by SKF 38393 in haloperidol-supersensitized animals. The antinociceptive action of intrathecally administered dopamine agonists appears to be mediated via D2-receptors. Whether the antinociception produced by SKF 38393 is exclusively contingent upon the activation of D1-receptors in the dopamine-supersensitive animal is as yet unresolved.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1987

Features of di George syndrome in a child with 45,XX,-3,-22,+der(3),t(3;22)(p25;q11).

A child with an unbalanced translocation resulting in monosomy for chromosomes 22 (q11----pter) and 3(p25----pter) is described. Although no immunological dysfunction could be demonstrated, the abnormalities found are similar to those seen in the di George syndrome which has been associated with monosomy for the same region of chromosome 22.

Chromosome Deletion↗
PubMed1987

Serological studies with influenza A(H1N1) viruses cultivated in eggs or in a canine kidney cell line (MDCK).

Pairs of influenza A(H1N1) viruses cultivated from the same clinical specimen in canine kidney (MDCK) cells or in embryonated hens' eggs can frequently be distinguished by their reactions with monoclonal antibodies to haemagglutinin and with antibodies in ferret or human sera. Egg-adapted virus, further passaged in MDCK cultures remained "egg-like" in serological characteristics indicating that the differences in their serological reactions were not a direct result of host cell-dependent glycosylation of the haemagglutinin. Haemagglutination-inhibiting (HI) or virus neutralizing antibodies in human sera can be detected more frequently, and to higher titre, in tests employing virus grown exclusively in MDCK cells than in tests with virus adapted to growth in embryonated eggs. Striking differences were detected in the serological reactions in HI tests when sera from ferrets infected with egg-grown virus were tested against a series of strains of influenza A(H1N1) virus isolated in 1983 and adapted to growth in eggs. In contrast, sera from ferrets infected with MDCK-derived virus failed to distinguish serologically between the same viruses that had been passaged exclusively in MDCK cells and also revealed relatively small differences between their egg-adapted counterparts.It was concluded that the cell substrate used for virus isolation and cultivation is a factor that should be considered when interpreting the results of strain characterization of influenza A(H1N1) isolates and in sero-surveys using these viruses.

Influenza A Virus, H1N1 Subtype↗
PubMed1987

A contribution to the discussion of probabilities and human hair comparisons.

The paper by Gaudette and Keeping on "An Attempt at Determining Probabilities in Human Scalp Hair Comparison" in the Journal of Forensic Sciences (Vol. 19, No. 3, July 1974, pp. 599-606) has provoked considerable controversy. This paper highlights two of the sources of the controversy and shows how the probability, 1/4500, quoted by Gaudette and Keeping should be treated with caution. The necessity of the use of a likelihood ratio statistic is described. It is suggested that the hair examination form resulting from the responses to the questionnaire recently distributed by the authors and also the discussions at Quantico (Proceedings of the International Symposium on Forensic Hair Comparisons, 25-27 June 1985, Quantico VA) should be used to facilitate the collection of the data which will be necessary to enable a likelihood ratio statistic to be estimated effectively.

Forensic Medicine↗
PubMed1986

Repair of a coccygeal vertebral fracture in a dog, using a four-hole finger plate.

A 7-year-old Pointer was referred with a transverse fracture of the 12th coccygeal vertebra. A 4-hole 2-mm finger plate was applied to the dorsolateral aspect of the vertrebra, and the tail was placed in a protective splint. This case presents an alternate method of fixation of coccygeal fractures, and is recommended when the nerve and blood supplies to the tail are intact, and when a cosmetic appearance with minimal callus formation is desired.

Animals↗
PubMed1986

Surgical management of the failed jejunoileal bypass.

The jejunoileal bypass is an efficient surgical treatment for morbid obesity, but it has a high complication rate that necessitates reversal in about 25 percent of patients. Conversion to Roux-Y gastric bypass was associated with acceptable morbidity and provided excellent control of weight. On the other hand, conversion to gastric partition resulted in weight gain almost equal to that seen with simple reversal alone. Conversion to Roux-Y gastric bypass is an acceptable procedure in the surgical treatment of the unsuccessful jejunoileal bypass.

Adult↗
PubMed1986

The value of microscopic features in the examination of human head hairs: statistical analysis of questionnaire returns.

There is an apparent diversity of opinion with respect to the probative value of hair in the United Kingdom and in North America. A questionnaire was devised and widely circulated in an attempt to discover the reasons behind this diversity and to seek the views of a broad range of hair examiners. This paper reports on the statistical analyses of the answers to the closed form questions. The majority of replies to most questions favored the number of categories given in the questionnaire. The general impression is that U.K. scientists tend to want fewer categories for classification of microscopic features than the North Americans. The largest divisions of opinion concerned pigment distribution and density and the medulla, where North American scientists want more categories for classification and the U.K. scientists fewer. The implications of these results in the choice and description of features to be examined in human hairs is considered in the second paper concerned with this questionnaire.

Forensic Medicine↗
PubMed1986

The value of microscopic features in the examination of human head hairs: analysis of comments contained in questionnaire returns.

Comments received in response to a questionnaire seeking opinion about hair examination have been considered. The questionnaire was in two parts: the first was concerned with the description of microscopic features and the second with the use of numerical features and data sheets in hair examinations. The same format is used to present a synopsis of the many individual comments and suggestions contained in questionnaire returns. It is argued that a hair examination form can contribute to more effective hair examinations although not replacing direct side-by-side comparisons. A hair examination form is presented with recommendations for its use.

Forensic Medicine↗
PubMed1986

Alterations in the DNA metabolism of MCa-11 mouse mammary tumor cells grown in vivo and in vitro.

Mouse mammary carcinoma (MCa-11) cells were grown in vitro in exponential, plateau-fed, and starved monolayer cultures or as 100-, 250-, and 500-microns tissue culture spheroids, and in vivo as small (4-mm diameter) and large (12-mm diameter) tumors. In all of these forms, the growth rates of the MCa-11 cells were found to decrease after an initial rapid proliferation of a relatively small number of cells. The DNA distributions of these cells during different rates of growth in vitro and in vivo, as well as the proportion and intensity of labeling of the S-phase cells with [3H]thymidine and [3H]deoxyuridine, were measured by flow and absorption cytometry. We found that significant numbers of MCa-11 cells remained in S phase, even after the growth rates in vivo and in vitro had slowed. However, as growth rates decreased, the intensity and proportion of S-phase cells labeled with exogenous DNA precursors decreased. We conclude that progressive alterations, including possible slowing and cessation, of replicative DNA synthesis occur in S-phase tumor cells as the metabolic constraints on tumor growth are increased.

Animals↗
PubMed1985

Topical antimicrobial toxicity.

Three topical antibiotics and four antiseptics (1% povidone-iodine, 0.25% acetic acid, 3% hydrogen peroxide, and 0.5% sodium hypochlorite) were directly applied to cultured human fibroblasts to quantitatively assess their cytotoxicity. The four antiseptics were found to be cytotoxic; all of the cytotoxic agents except hydrogen peroxide were subsequently found to adversely affect wound healing in an animal model. Comparison of bactericidal and cytotoxic effects of serial dilutions of these four topical agents indicated the cellular toxicity of hydrogen peroxide and acetic acid exceeded their bactericidal potency. Bactericidal noncytotoxic dilutions of povidone-iodine and sodium hypochlorite were identified. These experiments provide evidence that 1% povidone-iodine, 3% hydrogen peroxide, 0.5% sodium hypochlorite, and 0.25% acetic acid are unsuitable for use in wound care. This sequence of experiments could be used to identify bactericidal, noncytotoxic agents prior to their clinical use.

Acetates↗
PubMed1985

PIPIDA scan diagnosis of traumatic rupture of the gallbladder.

Eighteen days after injury, a patient was evaluated for bilious ascites with a 99mTc-PIPIDA (paraisopropyliminodiacetic acid) scan. A ruptured gallbladder was shown, and this finding was confirmed at exploration. Radionuclide scanning offers a sensitive, non-invasive approach for delineating disruption of the biliary tract, and should be considered when such a defect is suspected.

Aged↗
PubMed1985

Haematocrit in patients attending a hypertension clinic.

In view of recent interest in the relationship of haematocrit and blood viscosity to hypertension and vascular disease, we have analysed retrospectively the relationship of haematocrit to blood pressure, vascular complications and other variables in 2,381 patients referred to the Glasgow Blood Pressure Clinic. Haematocrit correlated negatively with age and systolic pressure in men, and positively with age and systolic pressure in females. Positive correlations were found in both sexes between haematocrit and serum alanine aminotransferase (possibly due to mutual correlation with alcohol); and between haematocrit and overweight (Quetelet Index) but not obesity (Ponderal Index). Increased haematocrit was also associated with cigarette smoking; and with history of angina, myocardial infarction and intermittent claudication in females. No correlation was observed between haematocrit and history of stroke. These findings suggest that prospective studies of haematocrit in hypertensives may be of interest.

Adult↗
PubMed1985

Endoscopic balloon dilation of outlet stenosis after gastric bypass.

Eighteen of 22 patients with stenotic gastrojejunostomies following gastric bypass surgery were successfully corrected by endoscopically placing a guidewire through the narrowed outlet and then passing a dilating balloon catheter over the wire. No complications occurred. All procedures were done without general anesthesia, and 64 per cent were done without hospitalization. This procedure can spare patients prolonged hospitalization for nasogastric decompression or reoperation, the two standard approaches to this problem. Successful use of this technique to dilate obstructed gastric partitions and distal esophageal strictures suggests that it may be considered for any gastrointestinal stenosis within reach of the endoscope.

Catheterization↗