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Biomedical subjects

M Collins

Publications and source records attributed to M Collins.

At least 235 records · Page 13Linked to original sources
PubMed1990

A novel T-cell protein which recognizes a palindromic sequence in the negative regulatory element of the human immunodeficiency virus long terminal repeat.

Two major protein-binding sites within the negative regulatory element of the human immunodeficiency virus type 1 long terminal repeat have been identified. One (site B) contained a palindromic sequence with homology to steroid/thyroid hormone response elements but was distinct from previously described binding sites of this class. A novel T-cell protein recognized the palindromic sequence within site B and also bound estrogen- or thyroid hormone-response elements with lower affinity. A 7-base-pair mutation in the site B palindrome, which destroyed protein binding, resulted in increased expression from the human immunodeficiency virus type 1 long terminal repeat in T cells.

Base Sequence↗
PubMed1990

Upper respiratory tract infection in children, domestic temperatures, and humidity.

STUDY OBJECTIVE: The aim of the study was to seek for a possible association between the incidence of upper respiratory tract infections and air temperature and humidity in the home. DESIGN: Recordings of temperature and relative humidity were made in living rooms and children's bedrooms over a six month period and related to incidence of upper respiratory tract infection. SETTING: The study was carried out in one general practice of 10,000 patients. PATIENTS: 297 children aged 24-59 months were studied, selected in random order from the practice age-sex register. MEASUREMENTS AND MAIN RESULTS: Temperature and humidity recordings were made with thermohygrograph recorders over six days. Upper respiratory tract infections were recorded (a) retrospectively over the previous 12 months, and (b) during the study period. Past history of acute otitis media and recent family history of respiratory infection were also obtained. No significant association was found between the variables, although the bedrooms of children with reported upper respiratory tract infections were cooler overnight than those of non-infected children (mean difference 0.8 degrees C, 95% confidence limits 0.7 degrees C). No association was found between reported or recorded upper respiratory tract infections and age or type of home, family size, level of occupancy, social class, or smoking habits. Only 15 children (5%) were identified by their parents as having had asthma, but 58 (19.5%) had had a "wheezy chest". A greater proportion of children who wheezed slept in cooler bedrooms, had gas fires rather than central heating, and had more smokers in the house. CONCLUSIONS: No association between upper respiratory tract infection and domestic temperature or humidity levels could be shown in this study. Since dampness is repeatedly presented as a health risk, further study is required.

Child, Preschool↗
PubMed1990

AIDS care funding.

Explore the source record for details and available documents.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Fibroblast growth factor in chick osteogenesis.

In vivo effects of FGF on osteogenesis in the chick embryo were evaluated. Day-11 embryos were injected with FGF followed by radiotracers. 3H-thymidine labelling of osteogenic cells was significantly higher following FGF administration; 3H-proline labelling over bone matrix was greater in the controls. Cartilage cells and matrix were sparsely labelled indicating a low level of metabolic activity. These data provide the first in vivo evidence that FGF stimulates osteogenic cell proliferation, while inhibiting production of bone matrix collagen. A role for FGF in embryonic osteogenesis and in fracture repair is suggested.

Animals↗
PubMed1989

EGF induces differentiation of an IL-3-dependent cell line expressing the EGF receptor.

Interleukin 3 (IL-3) is a T cell-derived lymphokine that supports the growth and development of hematopoietic cells. Tyrosine phosphorylation has been suggested to play an important role in IL-3-dependent cell proliferation. To test whether a growth factor receptor carrying a tyrosine kinase can be functional in IL-3 dependent cells, we used a retroviral vector to introduce the human EGF receptor into a murine IL-3-dependent pre-mast cell line, IC2. The EGF receptors expressed on the infected clones bind EGF with both high and low affinities. EGF stimulates the infected cells for a short term growth response. In the presence of IL-3 and EGF, infected clones differentiate into more mature mast cells characterized by increases in intracellular granulation and histamine content. This differentiation is reversible when EGF is removed. EGF induces tyrosine phosphorylation of several cellular proteins and the expression of oncogenes c-fos and c-myc, in a manner analogous to IL-3 stimulation. These results indicate that the EGF receptor is functional in the pre-mast IC2 cells; EGF can support short-term proliferation and activates the signals that induce cell differentiation. Thus, EGF receptor-expressing IC2 cells provide a unique cellular system for in vitro study of mast cell differentiation.

Animals↗
PubMed1989

Reduced exercise capacity of chronic obstructive pulmonary disease patients exercising with noseclip/mouthpiece.

A noseclip and low resistance mouthpiece are often used to monitor exhaled gases during exercise. Because otolaryngologic studies suggest that 50% of airway resistance is in the nose and mouth, it was hypothesized that patients with advanced chronic obstructive pulmonary disease might be artifactually limited by exercise testing with a noseclip and mouthpiece. Accordingly, 12 patients with stable chronic obstructive pulmonary disease performed identical symptom-limited supine bicycle exercise tests with and without noseclip and mouthpiece. Right-sided cardiac hemodynamic measurements, radionuclide ventriculography and arterial and mixed venous gas sampling were performed during each exercise test. Exhaled gases were analyzed during the noseclip/mouthpiece exercise. The order of exercise tests was alternated. Comparing exercises with and without a noseclip, there were significant reductions in exercise duration (397 +/- 270 vs 300 +/- 230 seconds, p less than 0.01), exercise oxygen consumption (780 +/- 279 vs 638 +/- 200 ml/min, p less than 0.01) and exercise cardiac output (8.4 +/- 2.7 vs 7.3 +/- 2.0 liters/min, p less than 0.05), an increase in right ventricular ejection fraction (0.39 +/- 0.08 vs 0.43 +/- 0.08, p less than 0.01) and no change in exercise heart rate (106 +/- 14 vs 106 +/- 14), right-sided cardiac pressures or arterial and mixed venous blood gases. These data suggest that a noseclip/mouthpiece can limit exercise tolerance in advanced chronic obstructive pulmonary disease patients. This limitation may result from decreased right-sided cardiac preload (venous return).

Adult↗
PubMed1989

Chloride transport in embryonic cells: effect of ethanol and GABA.

Ethanol and GABA (gamma-aminobutyric acid) and their interaction on 36Cl-influx were analyzed in cultured embryonic palate and limb mesenchymal cells in order to determine whether ethanol exerts its teratogenic action through a GABA receptor involved in embryogenesis. Cl- transport in secondary cultures of C57BL/6 palate mesenchymal cells was shown to consist of three systems including the electroneutral Cl-/HCO3- exchange (50%) and Na+/K+/Cl- cotransport (30%) pathways and the voltage-dependent Cl- channel (20%). Treatment with DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid) or SITS (4-acetamido-4'-isocyano-stilbene-2,2' disulfonic acid) in SWV palate cells inhibited the Cl-/HCO3- exchange pathway, while treatment with DIDS and bumetanide inhibited both the exchange and cation cotransport pathways, the residual Cl- influx inferred to be the electrogenic pathway. Inhibition of Cl- transport by anthracene-9-carboxylic acid confirmed the presence of the electrogenic Cl- pathway. It was observed that the rate of Cl- transport was significantly greater in palate cells of C57BL/6 mice than those of SWV mice. Also the rate of Cl- transport was significantly greater in secondary cultures of palate cells from C57BL/6 mice than from primary cultures of limb cells from the same strain. No evidence could be obtained that ethanol (10 to 100 mM) or GABA (3 X 10(-5) M) or their combination stimulated total Cl- influx in either C57BL/6 or SWV palate mesenchymal cells, putative voltage-dependent Cl- influx in C57BL/6 palate cells, or total Cl- influx in primary cultures of C57BL/6 limb mesenchymal cells.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1989

Age-related changes in naive and memory CD4+ T cells in healthy human children.

Subsets of CD4+ T cells originally identified functionally as suppressor-inducer and helper-inducer populations have recently been reinterpreted as naive and memory maturational states. The subsets can be identified by the surface expression of CD45R and CDw29, respectively. Using two-color flow cytometric analysis, we measured these CD4+ T cell subsets in two samples of cord blood and in 26 healthy children between the ages of 1 and 19 years. As has been reported by others, we observed that the majority of CD4+ T cells in cord blood consist predominantly of the CD45R+ subset. With aging we could demonstrate a gradual acquisition of CDw29+, CD4+ T cells and a concomitant gradual decrease in the percentage of CD45R+, CD4+ T cells. These age-related changes are consistent with the concept of naive (CD45R+) and memory (CDw29+) subsets. Further, because of the dynamic changes, their utilization as prognostic indicators in immunologic disease states cannot be applied to children in the same manner as adults.

Adolescent↗
PubMed1989

Myoglobin: an evaluation of its role as a marker of rhabdomyosarcomas.

Tumour markers now have an established role in tumour diagnosis and patient management. However, antibodies used to detect these tumour markers have in some instances proved unreliable, with a low rate of sensitivity and specificity. In this study we wished to evaluate the role of a commercial antibody to myoglobin as a marker of rhabdomyosarcomas. The purpose of this investigation was to assess the sensitivity and specificity of myoglobin antiserum as a marker of rhabdomyosarcomas. This was performed by reacting a large number of tumours (sarcomas, carcinomas and melanomas) with a polyclonal anti human myoglobin antiserum. Staining was demonstrated in 60% of rhabdomyosarcomas. Only two tumours from a total of 226 non-skeletal muscle tumours showed a positive reaction (0.88%). One was a leiomyosarcoma and the other had been classified as an undifferentiated sarcoma but a rhabdomyosarcoma was included in its differential diagnosis. It is of interest that both had been earlier irradiated. This antiserum was therefore a specific but not a very sensitive tumor marker. Its rate of staining of rhabdomyosarcomas is compared with the results in the literature. A great disparity is found and the reasons for this are discussed.

Adolescent↗
PubMed1989

Sex difference in muscle cross-sectional area of athletes and non-athletes.

The purpose of the present study was to determine whether there is a sex difference in limb muscle cross-sectional area by comparing upper- and lower-body limb fat-free cross-sectional areas (FFCSAs) adjusted for differences in fat-free weight (FFW), in male and female athletes with similar histories of upper-body physical conditioning and in non-athletes. Limb FFCSAs were calculated from circumferences corrected for subcutaneous fat thickness and FFW was estimated from body density measured by underwater weighing in 24 male and 25 female swimmers and 23 male and 25 female non-athletes, 15 to 28 years of age. The male swimmers had 32% larger FFWs and 49% larger upper-arm, similar forearm and 23% larger thigh FFCSAs compared to the female swimmers. The male non-athletes had 34% larger FFWs, 61% larger upper-arms, 54% larger forearms and 35% larger thighs than female non-athletes. To adjust for differences in body size, analysis of covariance was performed on the FFCSAs using FFW as the covariate. For the swimmers there were no significant differences (P greater than 0.05) in the adjusted FFCSAs. For the non-athletes, males had significantly larger adjusted upper-arm and forearm FFCSAs than the females but thigh FFCSAs were not significantly different (P greater than 0.05). These results suggest that sex differences in muscle area of the arms, may be partially attributed to long-term activity differences between sexes. Possible long-term differences in activity between sexes should be considered in comparisons of functional or performance measures between sexes.

Adolescent↗
PubMed1989

Combination therapy with gold and hydroxychloroquine in rheumatoid arthritis: a prospective, randomized, placebo-controlled study.

We studied combination therapy with two slow-acting antirheumatic drugs given concurrently in active rheumatoid arthritis (RA). A 12-month prospective randomized controlled trial compared gold and hydroxychloroquine in 52 patients to gold and placebo in 49. The patients continued to receive non-steroidal anti-inflammatory drugs and analgesics. They were selected from three rheumatology centres in the West Midlands. Combination therapy led to a greater number of withdrawals due to adverse reactions (18 cases compared to 10 receiving gold/placebo). Patients completing 12 months' therapy (27 taking gold/hydroxychloroquine and 32 on gold/placebo) were compared using five clinical, seven laboratory, and one radiological measure. All 13 variables favoured gold/hydroxychloroquine with an overall advantage of 20-25% for the combination. This only reached statistical significance (at the 1% level) for C-reactive protein. An overall disease activity index was better at 12 months (at the 5% level) and showed a more rapid response with gold/hydroxychloroquine. This is the first randomized prospective placebo-controlled trial to show a significant advantage from a combination of two slow-acting drugs. There are many different ways of giving such combinations and we consider these should be explored to maximize the effectiveness of treatment for RA.

Adult↗
PubMed1989

The value of NOR numbers in neoplastic and non-neoplastic epithelium of the stomach.

Using a silver staining technique, nucleolar organizer region-associated proteins (AgNORs) have been studied in paraffin sections of 15 benign gastric ulcers, seven early gastric cancers, 13 gastric adenocarcinomas and 10 control cases. A significant difference in the mean number of AgNORs per nucleus was found when control and benign groups were compared with the malignant group. However, there was an overlap between each category. Further studies are warranted to determine if this may be of value in differentiating regenerative epithelium from early malignancy.

Adenocarcinoma↗
PubMed1989

Blinking and corneal sensitivity.

We have investigated the relationship between corneal sensitivity and blinking patterns. Using a group of 9 young normal subjects, measurements were made of blink patterns, central and peripheral corneal sensitivity and lid margin sensitivity both before and after use of topical corneal anaesthetic, proxymetacaine hydrochloride (Alcaine). Blink patterns were recorded through concealed filming and were later analysed in terms of blink frequency and the type of blinks (proportion of complete, incomplete, twitch and forced blinks). Blink rate was significantly lower following anaesthetic administration, but the relative proportion of blink types remained unchanged. We speculate that one of the factors responsible for normal involuntary blinks is the imminent break-up of the tear film which is sensed by the cornea.

Adult↗
PubMed1989

Failure of zinc gluconate in treatment of acute upper respiratory tract infections.

Zinc is a trace metal with in vitro activity against rhinovirus, the major etiologic agent in acute upper respiratory tract infections (URIs). A previous trial of zinc gluconate supported its efficacy in treating URIs, but the effectiveness of blinding was uncertain. We conducted a prospective randomized trial of zinc gluconate versus a taste-matched placebo of sucrose octaacetate. Lozenges containing either 23 mg of elemental zinc or placebo were taken every 2 h. Eleven URI symptoms were rated daily on a scale of 0 (not present) to 3 (severe). Duration of illness, reflected in the proportion of subjects remaining symptomatic on each day, was not significantly reduced (maximum difference of 12.6% on day 7, P = 0.09; 95% confidence interval, -6 to 31%) by either treatment. Severity of illness, assessed by using a summed severity score, was reduced incrementally by 7 to 8% on days 5 to 7 (P = 0.02) in subjects taking zinc. Adverse effects, mostly nausea and altered taste, were reported by 50% of subjects taking zinc. We conclude that while zinc gluconate may produce a small reduction in overall severity of symptoms, this is not clinically significant. Given the additional high incidence of adverse effects, zinc gluconate cannot be recommended for use in the treatment of acute URIs.

Clinical Trials as Topic↗