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Biomedical subjects

C Robertson

Publications and source records attributed to C Robertson.

At least 253 records · Page 14Linked to original sources
PubMed1987

Pre-treatment with beta blockers and the frequency of hypokalaemia in patients with acute chest pain.

Plasma potassium concentration was measured at admission in 1234 patients who presented with acute chest pain. One hundred and ninety five patients were on beta blockers before admission. The potassium concentrations of patients admitted early (within four hours of onset of symptoms) were compared with those admitted later (4-18 hours after onset of symptoms). There was a transient fall in plasma potassium concentrations in patients not pre-treated with beta blockers. This was not seen in patients who had been on beta blockers before admission. Non-selective beta blockers were more effective than cardioselective agents in maintaining concentrations of plasma potassium. These findings suggest a mechanism for the beneficial effects of beta blockers on morbidity and mortality in acute myocardial infarction.

Adrenergic beta-Antagonists↗
PubMed1987

Breast cancer and colon cancer incidence in females in Scotland, 1960-84.

In view of the suggested similarity in risk factors for breast cancer and colon cancer in women, an analysis was undertaken to investigate age, period, and cohort influences on the risk of these diseases by use of incidence data for Scotland. Statistical modeling of data for the period 1960-84 revealed that both the age effects and the cohort effects were different for each site. While younger cohorts apparently had signs of reduced risk of both diseases, reduced risk was only apparent among the very youngest cohorts in the case of breast cancer, whereas there has been a gradual reduction in the risk of colon cancer among successive cohorts born since the beginning of the century. Clemmesen's hook was demonstrated in the age-incidence curve of breast cancer, which was clearly shown to have two different slopes: among premenopausal and among postmenopausal women. The declining risk of breast cancer in younger cohorts appeared contradictory to their apparently "high-risk" profile (in terms of present knowledge of etiologic factors) and suggested the possible existence of a factor that protects against breast cancer, at least at younger ages, but that remains, as yet, unidentified.

Adult↗
PubMed1987

Relationship between transcutaneous oxygen tension, ankle blood pressure, and clinical outcome of vascular surgery in diabetic and nondiabetic patients.

We measured ankle systolic blood pressure (ABP) and limb transcutaneous oxygen tension (TcPO2) before and after 53 vascular procedures performed to relieve limb-threatening ischemia. We compared changes in ABP and TcPO2 and also compared these measurements of limb hemodynamics with the clinical outcome of the vascular procedures. For the procedures performed on patients without diabetes, both ABP and TcPO2 registered similar changes after surgery. Furthermore, those nondiabetic patients who had a postoperative ABP greater than 75 mm Hg or TcPO2 greater than 20 mm Hg showed resolution of the clinical symptoms within 60 days after surgery. All patients falling below these levels underwent a subsequent limb amputation. The results differed somewhat for procedures performed on patients with diabetes. First, a number of diabetic patients showed high ABP in conjunction with low TcPO2. We attribute these observations to the high incidence in diabetic patients of calcific medial stenosis leading to artificially elevated ABP measurements. Second, the clinical outcome among diabetic patients was uncorrelated with the postoperative ABP and was poorly correlated with postoperative TcPO2. Those diabetic patients with postoperative TcPO2 below 20 mm Hg showed unfavorable clinical outcomes, but many patients with postoperative TcPO2 greater than 20 mm Hg and postoperative ABP greater than 75 mm Hg also showed unfavorable clinical outcome (slow healing of ulcers, persistence of rest pain, and/or an amputation on the limb). These data suggest that among our patients with diabetes, simple relief of limb ischemia was not sufficient to result in a trouble-free clinical course. We conclude that TcPO2 is a useful replacement or adjunct to ABP measurements for evaluating the hemodynamic outcome of vascular surgery. Our results also suggest that it is extremely important to evaluate the outcome of such surgeries separately in patients with and without diabetes.

Adult↗
PubMed1986

Evaluation of serum theophylline concentrations following administration of sustained-release beads in applesauce to asthmatic preschool children.

A sustained-release theophylline preparation (Theo-Dur Sprinkle) was evaluated in young asthmatic patients aged 1 to 6 years and receiving a daily dose of 23.4 +/- 2.0 mg/kg (mean +/- SD) to determine, on the basis of serial serum concentrations obtained over a 12-hour dosing interval at steady state, the suitability of such a product in patients likely to metabolize the drug very rapidly. Peak theophylline concentrations of 15.1 +/- 4.1 mg/L were achieved 5.5 +/- 1.5 hours after dosing. The mean maximum to minimum concentration difference was 6.9 +/- 2.2 mg/L for the dosing interval studied. Fluctuations in theophylline concentration less than 100% were achieved in nine of the 12 study patients. Use of the "sprinkle-technique" with Theo-Dur Sprinkle appears to be a simple and effective method of maintaining acceptable fluctuations in serum theophylline concentrations in preschool asthmatic children.

Asthma↗
PubMed1985

Snoring in children: is it pathological?

Some children who snore heavily, have been shown to have periods of apnoea which, if frequent, are known as the obstructive sleep apnoea syndrome (OSA). Twenty patients with OSA, who presented to the Department of Thoracic Medicine, Royal Children's Hospital, Melbourne, over a three-year period, were reviewed. The findings indicated that OSA is more common than is generally supposed and that it can present with a wide range of symptoms. It is important that an early diagnosis of this syndrome is made, to prevent major complications and to allow appropriate therapy.

Adenoidectomy↗
PubMed1985

A low-serum medium for tendon cells: effects of growth factors on tendon cell growth and collagen production.

Primary avian tendon cells maintain a higher percentage of net collagen synthesis when cultured in low serum concentrations than in high. However, under these conditions the cells grow slowly and can only be subcultured one or two times. We therefore examined various growth factors for their effects on tendon cell multiplication in order to develop a new medium for these cells. Of the growth factors tested, epidermal growth factor, insulin, transferrin, and selenium each stimulated tendon cell division. We also investigated how these factors affected collagen synthesis, and found that they all increased both collagen and noncollagen protein synthesis equally, thus leaving the percentage of protein synthesis devoted to collagen the same. When combined with 0.2% fetal bovine serum in Ham's F12 medium, epidermal growth factor and insulin together stimulated cell multiplication to a level comparable to that of cells grown in Ham's F12 plus 10% serum. Cells could also be successfully subcultured in this medium. Thus, by using selected growth factors we have reduced significantly the serum requirements of cultured tendon cells without affecting population doubling time or subculture capability. This low-serum medium should prove useful for the study of the regulation of collagen biosynthesis.

Animals↗
PubMed1985

Term infants with hypoxic-ischemic encephalopathy: outcome at 3.5 years.

A total of 167 term neonates with a diagnosis of hypoxic-ischemic encephalopathy (HIE) had detailed neurodevelopmental follow-up at 3.5 years of age. All 66 children with mild HIE were free from handicap; all seven with severe HIE were severely handicapped; and of the 94 with moderate HIE at birth, 21.3 per cent were handicapped. Mean IQ was significantly related to the category of HIE. Within the moderate HIE category, the neurological examination at discharge from the Neonatal Intensive Care Unit was more useful than the presence of neonatal convulsions in identifying children with subsequent developmental delay. Abnormalities on this examination related significantly to an increased number of handicapped children, decreased motor and language skills, and lower IQs. Although neonatal convulsions were associated with an increased number of handicapped children, they did not significantly affect most other developmental outcome measures. In term infants with documented HIE at birth, major neurodevelopmental dysfunction at 3.5 years depended more on prospectively established category of HIE than on other perinatal or social factors.

Asphyxia Neonatorum↗
PubMed1985

The effect of Parkinson's disease on the ability to maintain a mental set.

In two experiments with an Odd-Man-Out choice discrimination task, Parkinsonian subjects had difficulty in alternating between two rules on successive trials. The pattern of errors suggested that the difficulty arises from an instability of cognitive set rather than any loss of reasoning ability, perseveration or increased distractibility.

Adult↗