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Biomedical subjects

S Lloyd

Publications and source records attributed to S Lloyd.

At least 199 records · Page 11Linked to original sources
PubMed1971

Malformations of central nervous system and softness of local water supplies.

The mean annual prevalence at birth of congenital malformations of the central nervous system for the three years 1964-6 in 48 local authority areas in South Wales was negatively correlated (r = -0.402, P<0.01) with estimates of the mean total hardness of the related water supplies.The mean annual perinatal mortality rate from anencephalus for the five years 1963-7 in 58 county boroughs in England and Wales was also negatively correlated with estimates of the mean total hardness (r = -0.220, P>0.05) and calcium content (r = -0.289, P<0.05) of the related water supplies.It is concluded that the relationship between these associations may well be secondary. Analytical epidemiological studies of the association are called for.

Anencephaly↗
PubMed1967

The effect of oxytocin and adrenaline on blood flow in the hind limb of the dog following chronic lumbar sympathectomy.

1. In a number of dogs the last two lumbar ganglia were removed unilaterally. At various dates up to the 56th day after operation the dogs were anaesthetized and the effect of oxytocin and adrenaline on hind-leg blood flow studied. Oxytocin alone reduced leg flow in all dogs after operation.2. Until approximately day 11 after operation oxytocin given during an infusion of adrenaline increased leg blood flow, as it does in normal dogs not given adrenaline infusion. After that date it reduced the flow even during adrenaline infusion. The timing of this change suggests that the normal response to adrenaline depends on the presence of undegenerated nerve fibres.3. In one animal the sympathetic nerves were crushed between the last two lumbar ganglia and beyond the last, and hind-leg blood flow frequently measured by means of venous occlusion plethysmography until day 204, when the animal was anaesthetized and acute observations made. Electrical stimulation of the sympathetic chain above the site of crushing caused a reduction in leg flow, indicating that at least some of the nerve supply had regenerated. However, oxytocin reduced leg flow when used alone and exerted no apparent effect in the presence of adrenaline.4. It is suggested that sympathetic nerves to vascular smooth muscle have a function or functions other than transmitter release and that when crushed nerves regenerate the functions do not recover at the same rate.

Animals↗
PubMed1967

An examination of certain factors which might, or do, affect the vascular response to oxytocin.

1. A number of different observations were made on anaesthetized rats and some dogs to try to discover why it is that oxytocin is a vasodilator in dioestrus and anoestrus, and develops constrictor properties in oestrus and following sympathectomy.2. In those circumstances in which oxytocin in small or moderate doses raises blood pressure in the rat, the pressor effect is eliminated if the hormone is given during an infusion of adrenaline. In this respect the rat is closely similar to the dog.3. It was confirmed in anaesthetized oestrous rats that intravenous eserine eliminated the pressor response to oxytocin, and it was found that prostigmine did not reduce or change it. Thus, it may be concluded that the effect of eserine depends on its central sympathetic stimulant action and not on a peripheral effect.4. Rats which had been acutely or chronically adrenalectomized responded normally to oxytocin and both eserine and adrenaline were able to reduce, though not wholly eliminate, the pressor type of response. These results indicate that neither the adrenal medulla nor the cortex is essential for the action of oxytocin, nor for a large part of the action of eserine and adrenaline.5. The plasma concentrations of sodium, potassium and calcium were studied in a number of conditions affecting the response to oxytocin, namely, dioestrus, oestrus, and after administration of oestrogens, progesterone, adrenaline, eserine, hexamethonium, and dihydroergotamine. The cation changes observed could not be correlated with the type of response to oxytocin. The only measure found to affect the response was raising the plasma Na concentration by the infusion of disodium hydrogen phosphate. This reduced the pressor effect of oxytocin seen in oestrous female rats and in oestrogen treated males. The pressor response returned before the plasma sodium had fallen to normal levels.6. The administration of the oxytocin analogue, tyrosine-methyl(2) oxytocin which has a high receptor affinity and a low intrinsic activity, prevented the pressor response to oxytocin of oestrous rats, and the vasodilator response in the hind limb vessels of normal dogs. It is concluded that there is probably a single receptor for oxytocin from which both the constrictor and dilator effects are initiated.7. Oxytocin exerted apparently normal effects on the systemic blood pressure of oestrous or dioestrous rats given the beta-blocking agents pronethalol or propranolol.8. The present results, like previous ones, indicate that adrenaline is the factor linking both the gonadal state and the peripheral sympathetic nervous system with the type of response to oxytocin.9. An incidental observation was that male and female rats show differences in their response to sympathetic blocking agents and to a raised plasma sodium concentration.

Journal Article↗
PubMedDate not supplied

Glutamate receptor binding in the human hippocampus and adjacent cortex during development and aging.

Distinct patterns of age-related alterations in NMDA (MK801 binding) and non-NMDA, AMPA (CNQX), and kainate binding have been identified in human hippocampus and parahippocampal gyrus in normal individuals with no evidence of degenerative brain disease ranging in age from 24 gestational weeks to 94 years. Whereas MK801 binding did not alter substantially over this age range, CNQX binding rose from low levels in the fetus to maximum levels between neonate and middle age, and kainate binding declined extensively from the perinatal to adult stage. Following maturity, there were no significant changes in kainate binding, although MK801 binding increased in CA1 and CA3 and CNQX binding declined in several regions, particularly CA2 and subiculum. For each receptor binding the timing of these fluctuations ocurring during development and aging varied within different regions of the dentate gyrus, hippocampus proper, subicular complex, and entorhinal cortex examined. The transient peaks of receptor binding are likely to reflect processes of synaptogenesis and pruning and may provide clues regarding the role of the different glutamate receptor subtypes in various pathologies of the hippocampus and adjacent cortex associated with developmental disorders (of genetic origin or due to perinatal trauma or insult). The absence of substantial changes in any subtype examined from middle to old age suggests alterations in transmitter binding to these glutamate receptors are not involved in senescent neurodegeneration.

Adolescent↗
PubMedDate not supplied

Burnout, depression, life and job satisfaction among Canadian emergency physicians.

Our goal was to determine the level of burnout, depression, life and job satisfaction of Canadian emergency physicians. Six instruments were administered: the emotional exhaustion, depersonalization, and personal accomplishment intensity subscales of the Maslach Burnout Inventory (MBI); the Centre for Epidemiologic Research Self-Report Depression Scale (CES-D); the Satisfaction With Life Scale (SWLS); and the Emergency Physician Job Satisfaction Measurement Instrument (EPJS). Forty-six percent of the sample fell within the medium to high level of emotional exhaustion, 93% within the medium to high range for depersonalization, and 79% within the medium to low range for personal accomplishment. Sixty-one percent were satisfied with their lives, and 75.5% were satisfied with their jobs. Multiple regression analysis showed that increased age, being a department head, and increased weeks of holiday per year were positive contributors to EPJS scores (P < 0.05). Involvement in medical education, increased clinical hours worked per year, and region of residence-Quebec were negative contributors to EPJS scores (P < 0.05). Involvement in medical education is a significant factor among physicians experiencing depressive symptomatology. Time away from clinical practice is important to job satisfaction and emotional well-being.

Adult↗
PubMedDate not supplied

Lorazepam given the night before surgery reduces preoperative anxiety in children undergoing reconstructive burn surgery.

A high level of preoperative anxiety frequently occurs in children undergoing reconstructive burn surgery. Reduction of this anxiety may have a number of physiological and psychological benefits. Various pharmaceutical and nonpharmaceutical regimens to reduce preoperative anxiety have been devised; however, most regimens are not initiated until the period immediately before surgery. Many of the children in our institution report high levels of anxiety beginning the night before surgery. Therefore we hypothesized that sedation the night before surgery would be beneficial. Oral lorazepam 0.025 mg/kg or placebo was given the night before surgery to 45 patients in a prospective, randomized, double-blind fashion; in addition, all patients received preoperative sedation per protocol on the day of surgery. Immediately before induction of anesthesia, all patients (mean age 12.5 +/- 0.9 years, range 6 to 18 years) performed an anxiety self-rating with the use of a validated visual analog scale (VAS). Patient anxiety and quality of anesthesia induction was also rated by one of the investigators. Postoperatively, patients rated their recall of anxiety with the use of the VAS. When queried preoperatively, patients who received lorazepam the night before surgery self-reported significantly less anxiety than those receiving placebo. Investigator observations did not detect this difference; this reinforces the assertion that patient self-rating of anxiety may be the best tool for rating anxiety.

Adolescent↗
PubMedDate not supplied

The safety of adding bupivacaine to the subcutaneous infiltration solution used for donor site harvest.

Pain is a major problem for patients with burns. Donor sites are a significant source of this pain. In this investigation we hypothesized that bupivacaine infiltration of the donor site before skin harvest would prove to be a safe technique as determined by the measurement of blood levels of bupivacaine at various time intervals after infiltration. Fourteen patients were enrolled and studied. Average age was 14.3 +/- 3.1 years, weight was 43.1 +/- 9.1 kg, and donor site size was 6.3 +/- 2.0% TBSA. Mean dose of bupivacaine infused was 1.86 +/- 0.21 mg/kg. Maximum mean bupivacaine blood level was 0.39 +/- 0.09 microg/ml. The highest level measured in any one patient was 1.2 microg/ml; 4.0 microg/ml is considered to be the safe upper limit in children. Time to maximum blood level was 8.9 +/- 1.7 hours after infusion. Twelve of the 14 patients had measurable blood levels of bupivacaine at 24 hours after infusion. The maximum bupivacaine level was found to correlate significantly with both the mg/kg of bupivacaine infused (r =.60, P =.04) and the donor site size (r = 0.81, P = 0.002). Bupivacaine at a dose of slightly less than 1.9 mg/kg added to donor site infiltration solution is safe, as demonstrated by low blood levels and the absence of clinical signs of toxicity.

Adolescent↗
PubMedDate not supplied

Possible utility of serum determinations of CA 125 and CA 27.29 in breast cancer management.

The utility of measurement of serum levels of the tumor associated antigens CA 125 and CA 27.29 in detecting the presence of disease and in monitoring changes in disease status was examined in 63 patients with breast cancer. In patients with clinically detectable disease the CA 125 level was elevated in 59%, the CA 27.29 level in 59.5% and one or both markers in 84.6%. Specificity for presence of disease was 83.6% for CA 125, 88% for CA 27.29, and 69.1% for the two markers combined. Changes in marker levels of more than 50% correlated with clinical changes in disease status in 58% of cases for either CA 125 or CA 27.29 alone. In 87.5% of cases with clinically progressive disease one or both marker levels increased by more than 50% from the previous levels. In no case with greater than 50% increase in a marker level was there regression of disease. Thus, the use of these markers in combination might have utility in cases where diagnosis of recurrent disease is difficult or where monitoring of response to treatment is hampered by lack of measurable disease.

Adenocarcinoma↗
PubMedDate not supplied

Clinical evaluation of a new two-site assay for CA125 antigen.

As appropriate surgery and chemotherapy can improve both quality of life and survival of patients with ovarian adenocarcinoma, there has been a pressing need for "serodiagnostic" assays to enable close patient monitoring. CA 125 antigen has previously been described as a useful tumor marker of ovarian cancer. This is the first clinical evaluation of a radioimmunoassay using two new monoclonal antibodies, B27.1 and B43.13, that react with separate sites on the glycoprotein marker CA 125. Using the new assay, the majority of patients with clinically or radiologically detectable disease had serum CA 125 antigen levels well above the upper limit seen with random apparently healthy donors, while only three patients who were believed free of disease had elevated levels. Disease progression was associated with increasing values of serum CA 125 antigen, while response to therapy was associated with a steady decline in serum CA 125 antigen levels. Seven patients had steadily rising serum CA 125 antigen levels after initially having normal levels. The mean lead time between rise above normal and clinical or radiological evidence of relapse was 5 months (range 2 to 12 months). The merits of further surgical intervention are illustrated by the serial values of two patients followed after chemotherapy. The assay appears to have value in monitoring response to therapy and in detecting disease relapse at a time when appropriate therapeutic intervention is still possible or likely to be beneficial. Furthermore, monitoring CA 125 antigen was shown to be of benefit in assessing response to chemotherapy in a few patients with metastatic adenocarcinoma of unknown primary, and may be useful in this group of patients in determining those likely to benefit from aggressive chemotherapy.

Adenocarcinoma↗