Writing for publication: writing a book.
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Books↗
Biomedical subjects
S Morris
Publications and source records attributed to S Morris.
Complex mixtures and multiple agent interactions: the issues and their significance.
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Animals↗
Writing for publication: writing a book.
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Books↗
Pneumococcal carriage amongst children in Adelaide, South Australia.
Amongst 1267 healthy children 6 months to 4.5 years of age in Adelaide, the pneumococcal carriage rate from a single nasal swab sampling was 29% in the period 1980-1. Of 269 children, sampled monthly on five occasions, 91% carried a pneumococcus on one or more occasions: 55% carried a single type, 33% carried two types, 2% carried three types and 1% carried four types; 18% carried a pneumococcus on either 4 or 5 occasions. The commonest types encountered were types 6, 19 and 23 in that order, and these three types constituted 57% of the total: other common types (greater than 5% of the total) were types 14, 15 and 11, and the six commonest types constituted 77% of the total. Of these, types 6, 14, 19 and 23 commonly cause systemic disease in children; on the other hand types 11 and 15 cause disease infrequently. The number of strains showing antimicrobial drug resistance was low: on quantitative testing 0.7% of 291 isolates examined showed relative resistance to benzylpenicillin and 0.7% were resistant to tetracycline; 10.9% of 230 isolates examined showed resistance to co-trimoxazole; dual or multiple drug resistance was not detected, and all isolates tested were susceptible to chloramphenicol, erythromycin, lincomycin and rifampicin.
Carrier State↗
Role of metallothionein in detoxification and tolerance to transition metals.
Animal tolerance to the transition metals cadmium and zinc is hereditary. The evolution to a high level of resistance can be accelerated through mutation and selective pressure. We have studied inbred strains of mice and mutants of Chinese hamster ovary cells resistant to cadmium to further these understandings. Results with whole animals show that the difference in the rate and level of metallothionein accumulation is at most twofold between sensitive and resistant strains. However, with cadmium resistant CHO mutant cells, there is an over 60 fold increase in metallothionein and its mRNA upon induction. These mutants show over 60 fold amplification in metallothionein genes. These results offer a direct contrast in the correlation between elevation of metal resistance and increases in metallothionein between two genetic systems.
Animals↗
A randomised comparison of three drainage systems following cholecystectomy.
The efficacy of low pressure, high pressure and passive drainage systems have been compared after cholecystectomy. Symptoms of pain, discomfort and nausea were compared using linear analogue scales and spirometry was used to examine pre-operative and postoperative respiratory function. The low pressure suction drain removed an intraperitoneal marker, gentamicin, more effectively than the high pressure suction drain, but not more effectively than the passive drain. There were no differences in postoperative respiratory function nor in the amount of pain or discomfort between the groups. The passive drain group reported less nausea than the suction drain groups. If a negative pressure drainage system is to be used, a low pressure suction drain should be used in preference to a high pressure system.
Cholecystectomy↗
Transient response of amplified metallothionein genes in CHO cells to induction by alpha interferon.
Alpha interferon treatment of CHO cells elicits the rapid synthesis of many gene products, including metallothionein (MT), a protein which avidly binds heavy metals such as zinc, cadmium, and copper. Since MTs appear to have a pleiotropic role in the cell, ranging from metal detoxification to free-radical scavenging, interferon treatment may trigger a generalized defense mechanism. Activation by interferon, however, was transient, with MT mRNA being maximally detectable by a cytodot procedure within the first hour. Subsequent addition of interferon was ineffective until 7 h after the initial treatment. The action of zinc, a potent inducer of MT, however, remained independent of alpha interferon induction. The transient nature of induction by interferon was examined for altered rate of MT mRNA turnover.
Animals↗
Disruption of follicular maturation and delay of ovulation after administration of the antiprogesterone RU486.
To investigate the role of progesterone in the follicular phase, we examined the effects of RU486 in eight normal cycling women studied with daily and frequent blood sampling (every 10 min for 10 h) during three menstrual cycles (control-treatment-recovery). RU486 (3 mg/kg, orally) was administered for 3 consecutive days after ultrasound documentation of a dominant follicle. In six of the eight women, RU486 was given after emergence of the dominant follicle, while in two women, RU486 was initiated during the preovulatory period when estradiol levels had exceeded 917 pmol/L. In the six women given RU486 after emergence of the dominant follicle, RU486 significantly prolonged the follicular phase duration from 15.6 +/- 1.9 (+/- SD) to 28.6 +/- 9.3 days (P less than 0.01) and extended the treatment cycle length to 42.3 +/- 9.1 (+/- SD) days (P less than 0.01). During RU486 treatment, mean serum estradiol levels decreased from 385 +/- 43 to 228 +/- 28 pmol/L (P less than 0.01), while LH, FSH, ACTH, cortisol, and progesterone levels changed little. LH pulse frequency and amplitude on the last day of RU486 administration did not differ from control values. Collapse of the dominant follicle was evident on ultrasound after RU486 administration and was not accompanied by uterine bleeding. In the two women treated during the preovulatory period, the follicular phase was not prolonged, and RU486 failed to delay the onset of the LH surge. Our findings indicate that RU486 treatment during the follicular phase interrupts normal follicular development, resulting in a delay of ovulation and a reinitiation of follicular recruitment.
Adrenocorticotropic Hormone↗
Bronchial anastomosis with a tissue adhesive.
Air leakage and necrotic degeneration may occur after bronchial anastomosis and can lead to death from secondary pneumothorax and pneumonia. We studied the ability of a new tissue adhesive (N-butyl-cyanoacrylate monomer) to enforce the bronchial suture line. The left main bronchus in each of five pigs in Group A was completely transected and closed by four stitches and tissue adhesive. The transected left main bronchus in each of the other five pigs in Group B was connected with 11 to 14 interrupted polyglycolic acid 3-0 sutures. The time required for reconstruction was 10 +/- 3.6 minutes in Group A and 25.0 +/- 6.5 minutes in Group B. No symptoms of a constricted airway were apparent in Group A. All pigs were examined at an interval of from 5 to 8 weeks after operation. Evidence of infection at the bronchus appeared in three animals: two in Group A and one in Group B. One instance of air leakage at the anastomosis occurred in Group B. We measured the maximum tensile strength of the bronchial suture line by means of an electromechanical testing machine comparing the tensile strength of the treated left bronchus with that of the control right bronchus. The maximum tension of the treated bronchus in Group A was 10.3 +/- 1.52 (pounds) and that of control was 8.0 +/- 1.56 (pounds) (p less than 0.05). The maximum tension of Group B was 7.93 +/- 0.29 (pounds) on the treated side and 6.78 +/- 0.32 (pounds) on the control side (p less than 0.05). The suture line with tissue adhesive was enforced sufficiently to act as a stable connective tissue. Histologic studies in Group A revealed that the suture line was completely healed without tissue damage and was strengthened by the tissue adhesive.
Animals↗
Thallium heart scanning: its value in the management of coronary artery disease.
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Coronary Artery Bypass↗
Exercise-induced left bundle branch block and its relation to coronary artery disease.
The records of 2,584 consecutive patients who underwent both treadmill exercise testing and coronary cineangiography were reviewed to determine the relation between exercise-induced, acceleration-dependent left bundle branch block (LBBB) and the presence of coronary artery disease (CAD). Rate-dependent LBBB during exercise was identified in 28 patients (1.1%), who were categorized according to their presenting symptoms: classic angina pectoris, atypical chest pain, symptomatic cardiac arrhythmia and asymptomatic. Asymptomatic patients underwent a screening exercise test. CAD was present in 7 of 10 patients who presented with classic angina pectoris, but 12 of 13 patients presenting with atypical chest pain had normal coronary arteries. All 10 patients in whom LBBB developed at a heart rate of 125 beats/min or higher were free of CAD, whereas 9 of 18 patients in whom LBBB developed at a heart rate of less than 125 beats/min had CAD. Normal coronary arteries were present in 3 patients who presented with angina and in whom both chest pain and LBBB developed during exercise. It is concluded that patients who present with atypical chest pain in whom rate-dependent LBBB develops on the treadmill are significantly less likely to have CAD than patients who present with classic angina; the onset of LBBB at a heart rate of 125 beats/min or higher is highly correlated with the presence of normal coronary arteries, regardless of patient presentation; and patients with angina in whom both chest pain and LBBB develop during exercise may have normal coronary arteries.
Adult↗
Is serum selenium a risk factor for cancer?
A narrow band of counties extending along the southeastern Atlantic coast from Jacksonville, Florida to Charleston, South Carolina were found to have excessively high incidence rates for esophageal cancer in non-white males. White males in the same areas have a 30% higher incidence rate for lung cancer but only average incidence rates were found for non-white males. Selenium is considered to decrease cancer risk in the animal model. In this coastal region, a study of 130 cancer patients who developed a malignancy 2-12 years after baseline examination showed no dose response relationship between baseline serum selenium levels and risk of subsequent cancer.
Black People↗
Cellular heterogeneity in the expression of the delta-crystallin gene in non-lens tissue.
RNA transcripts of the delta-crystallin genes, which code for the major chicken lens protein, have been detected at low levels in many non-lens tissues. Here it is demonstrated by in situ hybridisation that these transcripts are concentrated at a high level in small, infrequent clusters of cells in many non-lens tissues. While the nuclei of these cells are very heavily labelled, there is only light labelling of the cytoplasm. The unlabelled cells surrounding the labelled clusters are of similar morphology and staining properties as the labelled cells, and all have the characteristic morphology of cells of the embryonic tissue used. With the exception of neural retina, it is not yet known whether the labelled clusters are found in specific locations in the tissues, or whether they arise at random.
Animals↗
Pneumococcal carriage amongst Australian aborigines in Alice Springs, Northern Territory.
In Alice Springs and its vicinity, a single nasal swab was collected from 282 Australian aborigines in May 1981 to determine nasal carriage rates of pneumococci. Each swab was inoculated on blood agar and on gentamicin blood agar. The carriage rates were 89% in children, 39% in adolescents and 34% in adults. In all, 27 serotypes of pneumococci were met with and 15 (4%) of subjects yielded two or more serotypes. In children, types 23, 19, 6, 22 and 6 were predominant (in that order), whereas type 3 was commonest in older subjects. Approximately 25% children and 5% adults yielded drug-insensitive pneumococci. Resistance to benzylpenicillin, tetracycline and co-trimoxazole was met with, resistant pneumococci showed five resistance patterns and belonged to nine serotypes, predominantly types 19 and 23. All isolates were sensitive to chloramphenicol, erythromycin, lincomycin and rifampicin. The carriage rate of drug-insensitive pneumococci was 100-fold higher amongst children sampled than in non-aboriginal children in Australia.
Adolescent↗
Lysis of human cytomegalovirus infected fibroblasts by natural killer cells: demonstration of an interferon-independent component requiring expression of early viral proteins and characterization of effector cells.
We investigated the susceptibility of cells infected with human cytomegalovirus (HCMV) to lysis by human natural killer (NK) cells, examining in particular its relationship to sequential viral protein expression, interferon (IFN), and the nature of the effector cells. HCMV-infected fibroblasts were lysed by peripheral blood mononuclear cells from normal seronegative individuals. The effector cells were large granular lymphocytes of Leu-7+, Leu-11+, and to a lesser extent Leu-7- phenotype. Depletion studies suggested they were the same population of NK cells that lyse uninfected fibroblasts, but a subset of NK cells that lyse K562 cells. HCMV-infected cells treated with phosphonoformate and cells infected for 16 hr that only express the nonstructural HCMV immediate early and early proteins and not the late (structural) proteins were susceptible to lysis by IFN-pretreated effector cells, whereas cells expressing immediate early antigens alone were not. This enhanced susceptibility to lysis was associated with increased effector:target binding in target cell binding assays, and was competitively inhibited by uninfected fibroblasts in cold target competition assays. It was independent of IFN release from the infected target cells or effector cells. These results suggest that the increased susceptibility to lysis by NK cells produced by a human herpes virus HCMV i) is manifest when early viral proteins are expressed, ii) is related to enhanced expression of a target structure likely to be present on uninfected fibroblasts, and iii) has a major component that is independent of IFN.
Adult↗
The immunosuppressive effects of measles virus on T cell function--failure to affect IL-2 release or cytotoxic T cell activity in vitro.
Measles virus (MV) is known to depress T cell function. In order to determine whether this results from alteration in the production of, or response to, interleukin-2 (IL-2) we studied the effect of in vitro infection with MV on human IL-2 dependent T cell lines. MV produced a cytopathic productive infection in these cells. Class I allospecific cytotoxic T cells retained their cytotoxic activity 48 h after infection. Both cytotoxic and Leu 3a/4a positive T cell lines continued to respond to IL-2 by proliferation up to 26 h after infection. The ability of human tonsillar lymphocytes to generate IL-2 in response to phytohaemagglutinin following MV infection was then studied. In early measles infection (up to 48 h) there was no suppression of IL-2 production: in fact measles infected cells spontaneously released low levels of IL-2 in the absence of lectin. Similarly, IL-2 release was not affected by Herpes simplex virus infection of such cultures, although lymphocytes infected with Sendai or respiratory syncytial viruses produced considerably less IL-2. These observations suggest that MV-induced immunosuppression is not a result of inhibition of differentiated T cell function, IL-2 generation or responsiveness, but may be more directly related to virus-induced cytopathic effects in activated T cells.
Cell Line↗
Oxygen consumption by Palaemon elegans (Rathke) in response to temperature change: a determinant of distribution.
The distribution of the intertidal rock pool prawn Palaemon elegans Rathke, on a rocky shore of the Isle of Cumbrae in west Scotland, was investigated. Prawns of all sizes were abundant in the mid- to high-shore pools throughout the summer until September when the largest individuals began to dissappear from the shore. Small and large P. elegans were found to be distributed on the shore in different ways. The small prawns found on the shore during the winter exhibited a much altered behaviour. In the laboratory, the effect of temperature change on oxygen consumption was assessed as was the role of temperature acclimation in determining the rate of oxygen consumption. Oxygen consumption calculated as a weight specific rate (Mo2) could be negatively correlated with body weight. This relationship between body weight and oxygen consumption was different in prawns acclimated to 10 and 23 degrees C and is considered to be an acclimatory response. The acute response, of prawns acclimated to a given temperature, to changes in temperature was similar in different sized prawns. After an acclimatory period of between 1 and 2 weeks small prawns exhibited positive acclimation of oxygen consumption whereas the larger prawns appeared to be unable to acclimate. This variable size dependent, response is discussed as a determinant of distribution and behaviour.
Acclimatization↗
Modulation of haemocyanin oxygen affinity in the intertidal prawn Palaemon elegans (Rathke).
The modulation of haemocyanin oxygen affinity was studied at 10 degrees C in the blood of the intertidal prawn Palaemon elegans. On increasing the L-lactate concentration in dialysed blood from 0 to 9.1 mM, P50 decreased from 27 to 11 torr at pH 7.8. Undialysed blood exhibited a higher oxygen affinity than dialysed blood with the same lactate concentration indicating the presence of an unidentified factor which increased oxygen affinity. After dialysis both winter and summer blood exhibited the same intrinsic oxygen affinity and response to lactate. The response of oxygen affinity to lactate was exponential, low concentrations of lactate (0-5 mM) markedly increasing oxygen affinity. The lactate effect in dialysed blood expressed as delta logP50/delta log[L-lactate] was -0.56 at pH 7.8 and -0.63 at pH 7.4. The effect of lactate on oxygen affinity, delta P50, was similar in dialysed and whole blood. The effect of the unidentified factor (delta P50, between dialysed and undialysed blood) at the same lactate concentration was 13.1 and 15.1 torr at pH 7.8 in winter and summer blood, respectively. At pH 7.4 the delta P50 was 38 torr for both summer and winter blood. Differences in oxygen affinity between blood collected in summer and winter could be explained by differences in blood lactate concentrations.
Animals↗