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Biomedical subjects

M Herbert

Publications and source records attributed to M Herbert.

At least 91 records · Page 5Linked to original sources
PubMed1987

Low dose aminophylline accelerates recovery from diazepam premedication for digestive endoscopy.

The value of intravenous aminophylline in accelerating recovery from premedication with diazepam was assessed against placebo in a randomized, double-blind trial. One hundred ten patients undergoing routine diagnostic upper gastrointestinal endoscopy received diazepam intravenously in a dosage sufficient to achieve adequate sedation. On completion of the endoscopy, patients received either aminophylline (1.5 mg/kg) or placebo. Recovery from sedation was assessed on clinical grounds by a nurse, objectively using a serial reaction time test, and by the patient on a visual analogue scale. The number of patients judged to be fully alert at 30 and 60 min after the procedure was significantly greater in the aminophylline group than in the placebo group. Compared with values obtained before sedation, the placebo group had significantly prolonged reaction times 30 min after completion of the endoscopy, whereas patients who received aminophylline did not. However, according to their self-assessments, patients in both groups felt more uncoordinated following sedation. Aminophylline appears to hasten recovery from sedation with diazepam, and its use may permit earlier mobilization of patients after endoscopy.

Adult↗
PubMed1987

Psychological intervention in civilian flying phobia. Evaluation and a three-year follow-up.

Thirty-eight people with a moderate to severe degree of aerophobia self-referred themselves to a course designed to help them travel by air. The course involved three long sessions based on giving information, graded exposure without avoidance, and group support with natural coping models. Measures of self-reported anxiety levels were taken at regular intervals. The results showed that being given information or undergoing a simulated flight had little effect on perceived anxiety. Prolonged exposure to flying had a marked effect on reducing anxiety and anticipated apprehension about future flying. At one-year and three-year follow-up, 40% and 60% of participants had flown commercially, although there was some minor restoration of anticipated anxiety associated with flying; 84% showed less anxiety about flying. Psychological intervention, in collaboration with airlines, may have marked benefits in reducing fear of flying.

Adult↗
PubMed1986

Correlation between anxiety and serum prolactin in humans.

The organised social structure of primate species largely determines individual behaviour. Moreover Keverne et al. in Advanced Views in Primate Biology, Springer, Berlin (1982) [1] have demonstrated that social interaction among confined male talapoin monkeys may result in endocrine changes, and that these in turn may modify behaviour. We have undertaken a study to determine whether similar endocrine changes can be induced in confined human volunteers. Five men were confined on a boat for fourteen days. Repeated plasma samples were taken under controlled conditions for assay of testosterone, prolactin and cortisol. After each sample the men completed a questionnaire to document self-perceived anxiety. The men were also secretly ranked for dominant/aggressive behaviour towards the other males. Significant correlation was found between day-to-day changes in anxiety and stress hormones, cortisol and prolactin. Significant correlation was found also between plasma prolactin, testosterone and rank position for dominance/aggression. It is concluded that under some circumstances social interaction may modify endocrine status in humans.

Adult↗
PubMed1986

Overlapping promoters and their control in Escherichia coli: the gal case.

Two overlapping promoters compete for RNA polymerase in the region that controls the expression of the galactose operon in Escherichia coli. Kinetics of open complex formation at P1 and P2 can be followed through the rate of formation of two specific abortive transcripts. The corresponding forward kinetic constants appear to be identical over a wide range of enzyme concentrations and temperatures, indicating that the two processes are strongly coupled. We propose a scheme accounting for our observations. In a first step, the competition between the two sites is a simple kinetic process, involving the "on" rate constants. In a second step, a slow reequilibration occurs, implicating the "off" rate constants and the conversion of one open complex to the other through a set of closed complexes. The first step is clearly affected when the complex between cyclic AMP and its receptor is bound at the activator site. An estimate of the various rate constants describing open complex formation at P1 and P2 is provided, as well as a qualitative description of the effect of the activator complex on these two pathways.

Cyclic AMP↗
PubMed1986

Prolactin and stress: some endocrine correlates of pre-operative anxiety.

An attempt was made to correlate the serum concentration of PRL, GH and cortisol with anxiety experienced before elective surgery. A significant direct correlation was observed between cortisol and anxiety (P = 0.028), and between GH and anxiety (P = 0.001) although the latter correlation may have reflected the confounding effects of sex and age on GH levels. No correlation was observed between anxiety and PRL and we conclude that psychosocial stress cannot be invoked as an occasional cause of hyperprolactinaemia.

Aged↗
PubMed1985

The measurement of helplessness in rheumatoid arthritis. The development of the arthritis helplessness index.

We describe the development of the Arthritis Helplessness Index (AHI), a self-report instrument designed to measure patients' perceptions of loss of control with arthritis. The participants in this research were 219 patients with rheumatoid arthritis (RA) who completed a quantity of mailed materials, including the AHI, functional measures and other psychological scales. Significant evidence of reliability and validity of the AHI was found. Greater helplessness correlated with greater age, lesser education, lower self-esteem, lower internal health locus of control, higher anxiety, and depression, and impairment in performing activities of daily living using a health assessment questionnaire. Over one year, changes in helplessness correlated with changes in difficulty in performing activities of daily living. The AHI appears to be a useful measure for further studies in RA and a valuable clinical tool in monitoring the psychological status of patients with RA.

Adolescent↗
PubMed1984

Night shift paralysis.

12% of night nurses surveyed claimed to have suffered from a totally incapacitating paralysis that may be related to sleep paralysis, and contribute to impaired levels of safety on the night shift. The incidence of this paralysis is shown to be age-related, largely confined to the early hours of the morning, and to increase over consecutive night shifts.

Adult↗
PubMed1984

The effects of acute or chronic ingestion of propranolol or metoprolol on the physiological responses to prolonged, submaximal exercise in hypertensive men.

We have studied the physiological responses to 50 min of intermittent, moderate exercise in hypertensive men after the ingestion of a single dose of placebo, propranolol or metoprolol, and also after 28 days treatment. In addition, subjective assessments of mood were made during the last 7 days of each period of chronic treatment. Heart rate and blood pressure, both at rest and during exercise, were significantly reduced by a single dose of propranolol or metoprolol; more marked effects were observed after chronic treatment. Ventilation and gas exchange during exercise were only slightly disturbed by single doses of propranolol or metoprolol, whereas chronic treatment had no effect. Perceived exertion scores were increased after a single dose of either drug, compared to placebo, and the effect of propranolol was greater than that of metoprolol. With chronic treatment there were fewer differences between the perceived exertion scores during exercise, although 'leg' fatigue remained greater after propranolol than after placebo. Sweating from the forehead during exercise was enhanced by a single dose of either beta-adrenoceptor antagonist, with propranolol having the greater effect. After chronic treatment the effect of propranolol was diminished, whereas the effect of metoprolol was maintained. Very few disturbances of mood were found after chronic ingestion of the beta-adrenoceptor antagonists.

Adult↗
PubMed1983

Profile of recovery after general anaesthesia.

The duration of impairment of mental functioning after anaesthesia was studied in 55 patients undergoing hernia repair who were divided into three groups in which the method of induction of anaesthesia (intravenous or inhalational) and ventilation (spontaneous or controlled) was varied. Performance in a five minute serial reaction time test and subjective estimates of coordination were assessed four times a day for two complete postoperative days and were compared with those in a control group of orthopaedic patients in hospital. After considerable impairment initially, reaction times in all groups gradually returned towards control values, but in patients breathing spontaneously during anaesthesia impairment recurred during the second postoperative day. These results suggest that such patients should be advised not to undertake hazardous tasks such as driving a car for at least 48 hours after a general anaesthetic. Discrepancies between subjective and objective assessments of impairment also suggest that patients should not rely on their own assessments of fitness to drive.

Anesthesia, General↗
PubMed1983

Comparison of the binding sites for the Escherichia coli cAMP receptor protein at the lactose and galactose promoters.

Polyacrylamide gel electrophoresis has been used to visualise and quantitate complexes between the Escherichia coli cyclic AMP receptor protein (CRP) and DNA fragments containing the promoter region of either the E. coli galactose or lactose operons. We show that, although CRP binding to the gal fragment is weaker than binding to the lac fragment, in each case, stable complexes are formed between one dimer of CRP and one molecule of DNA. We have examined the effects of a series of deletions and point mutations in the gal promoter region on CRP binding. From the position of deletions and mutations which prevent the formation of stable complexes, we deduce the location and extent of the sequence at the CRP binding site. We show that it covers approximately the same length of sequence as the binding site at the lac promoter. Unlike the lac site, the gal site contains no palindromic sequence. We discuss the importance of symmetry in the sequence at CRP binding sites and the validity of CRP binding consensus sequences which have been proposed.

Binding Sites↗
PubMed1983

A comparison of some psychological and physiological effects exerted by zetidoline (DL308) and by oxazepam.

In a double-blind, balanced crossover study, eight healthy male volunteers ingested either DL-308 (10 mg), DL-308 (20 mg), oxazepam (30 mg) or placebo. Subjective estimates of coordination and anxiety, objective performance measurements and cardiovascular measurements were taken at 1, 3, 5 and 8 h after ingestion. DL-308 (20 mg) exerted a strong sedative effect as judged by self-reported coordination scores and performance on logical reasoning and reaction time tests. The effect was evident almost immediately and, on the coordination and reasoning tests, lasted up to 8 h following ingestion. Attention is drawn to the need to extend performance testing in order to maximise test sensitivity. No drug had any consistent or strong influence on cardiovascular measures.

Adult↗
PubMed1983

Circadian variation in effects of ethanol in man.

Twenty normal male volunteers received an intoxicating dose of oral ethanol (2 ml/kg vodka) and impairment of psychological functioning was documented over the succeeding 90 min. Half the subjects received ethanol at 0900 hr and half at 1800 hr. Those who received ethanol in the morning performed worse in tests of reaction time (p less than 0.002) and logical reasoning (p less than 0.002), even though blood alcohol levels were similar in the two groups. It is concluded that there is a circadian rhythm in the effects of ethanol in man.

Adult↗
PubMed1983

Primate experiments in malocclusion and bone induction.

It has been recognized for many years that muscle function influences bone formation and morphology. It is hypothesized here that the movement of bone into new positions within a muscle system results in rearrangement of the stress distribution and reorganization of shape and internal structure. To test the above hypothesis, clinical and animal experiments involving the use of posterior occlusal bite blocks, Herbst appliances, and temporal and masseter muscle stimulation were undertaken. Chronic or continuous alteration in mandibular position within the neuromuscular environment with the posterior occlusal bite block and the Herbst appliance in a sample of monkeys produced extensive condylar remodeling and change in mandibular size. Short periods of induced hyperactivity in the masseter and temporal muscles were associated with the production of malocclusion symptoms. Excess induced temporal muscle activity of specific frequency and intensity may interfere with the remodeling of bone grafts placed under the temporal muscle, while a lesser level of activity was associated with bone remodeling.

Animals↗
PubMed1983

Intracellular compartmentation of isozymes of sugar phosphate metabolism in green leaves.

The present paper has summarized evidence for the presence of two isozymes for many enzyme activities of sugar phosphate metabolism in plant leaves. These two isozymes are clearly compartmentalized in the chloroplasts and in the cytosol of plant leaf cells. In C4 plants there exists an additional isozyme in the mesophyll cells of these leaves in addition to the two isozymes in the bundle sheath cells. Such cell-compartment-specific and cell-specific isozymes provide duplicate (and possibly triplicate) enzyme systems for complete or almost complete pathways (ie, glycolysis, gluconeogenesis, and the oxidative pentose phosphate pathway). They provide a basis for the understanding as to how many isozymes one may expect in plants. They also provide a challenge to determine what their function is particularly in the differential regulation of metabolic pathways in different cell compartments. Based on his genetic analyses Weeden [1981] has recently proposed a model for the evolution of chloroplast-specific isozymes of sugar phosphate metabolism. This model rests on the endosymbiotic theory for the origin of chloroplasts. It still is highly speculative. However, cell-compartment specific isozymes may eventually provide a means of studying plant evolution, especially if we succeed in analyzing their primary structure.

Antigen-Antibody Complex↗
PubMed1983

[Electron microscopic and morphometric studies of the main kidney segment of male and female rats following castration and testosterone substitution].

The effect of testosterone on the 3 segments of the renal proximal tubule (S1, S2, S3) of male and female rats was studied by electronmicroscopic and morphometric methods. Only light, granulated and dark lysosomes as well as microbodies (peroxisomes) and dictyosomes (Golgi zones) were investigated. After castration the area density of light lysosomes in the S1 segment increases in males whereas it decreases in females; therefore the sex different pattern of light lysosomes, that is to be seen in normal animals, is reversed. The absolute size and number of light giant lysosomes is also elevated in castrated males in comparison to normal animals as well as to animals substituted by testosterone. - Dark lysosomes of the S1 segments are more numerous in castrated females and less numerous in castrated males than in normal animals. - The distinct sex difference in dark lysosomes of the S2 segment which is demonstrable in normal animals disappears after castration the area density of dark lysosomes increasing in castrated females and decreasing in castrated males. The three species of lysosomes in the S1 segments show no longer a sex difference after substitution with testosterone: substituted males develop the same pattern as normal animals and substituted females are almost comparable with normal males. However, the sex difference in dark lysosomes of the S2 segment is more pronounced after testosterone treatment. - The characteristic pattern of light lysosomes in the S1 and S2 segments as well as the change of the sex different lysosomal pattern after castration and substitution with testosterone, respectively - especially in S1 - seem to be caused by testosterone which results in an inhibition of resorption. Only after castration a sex difference appears in dark lysosomes of the S3 segment (males show more dark lysosomes than females). This sex difference is reversed by testosterone treatment. There are more numerous lysosomes with an non-homogeneous matrix in both sexes after castration which are seldom to be seen in normal and substituted animals. The area density of microbodies shows sex differences in all 3 segments of normal animals. While no significant changes in S1 and S2 are to be seen after castration and substitution, there is a pronounced decrease of the area density of microbodies in S3 of males after castration, so that no sex differences are then available.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗