Search PubMed⌕ Search

Biomedical subjects

D Holland

Publications and source records attributed to D Holland.

At least 73 records · Page 4Linked to original sources
PubMed1987

Automation in clinical microbiology: a new approach to identifying micro-organisms by automated pattern matching of proteins labelled with 35S-methionine.

A new rapid automated method for the identification and classification of microorganisms is described. It is based on the incorporation of 35S-methionine into cellular proteins and subsequent separation of the radiolabelled proteins by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The protein patterns produced were species specific and reproducible, permitting discrimination between the species. A large number of Gram negative and Gram positive aerobic and anaerobic organisms were successfully tested. Furthermore, there were sufficient differences within species between the protein profiles to permit subdivision of the species. New typing schemes for Clostridium difficile, coagulase negative staphylococci, and Staphylococcus aureus, including the methicillin resistant strains, could thus be introduced; this has provided the basis for useful epidemiological studies. To standardise and automate the procedure an automated electrophoresis system and a two dimensional scanner were developed to scan the dried gels directly. The scanner is operated by a computer which also stores and analyses the scan data. Specific histograms are produced for each bacterial species. Pattern recognition software is used to construct databases and to compare data obtained from different gels: in this way duplicate "unknowns" can be identified. Specific small areas showing differences between various histograms can also be isolated and expanded to maximise the differences, thus providing differentiation between closely related bacterial species and the identification of differences within the species to provide new typing schemes. This system should be widely applied in clinical microbiology laboratories in the near future.

Automation↗
PubMed1986

Functionally important conserved amino-acids in interferon-alpha 2 identified with analogues produced from synthetic genes.

A gene was chemically synthesised and expressed in Escherichia coli to produce [Ala30,32,33]IFN-alpha 2, an analogue of human alpha 2-interferon (IFN-alpha 2) which is devoid of activity on human cells. Eight additional analogues provided single changes in IFN-alpha 2 at each of these three conserved positions. No one residue is essential for activity, but both antiviral and anti-proliferative activity are particularly sensitive to changes in the side-chain of Arg33.

Amino Acids↗
PubMed1986

Method for the typing of Clostridium difficile based on polyacrylamide gel electrophoresis of [35S]methionine-labeled proteins.

A typing method for Clostridium difficile based on the incorporation of [35S]methionine into cellular proteins, their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and their visualization by autoradiography is described. On analysis of the radiolabeled-protein profiles, nine distinct groups were observed (A to E and W to Z). The method, which is simple, reproducible, and readily expandable, has been applied in epidemiological studies to demonstrate cross-infection and hospital acquisition of C. difficile.

Adult↗
PubMed1985

Coronary blood flow during variation in coronary perfusion pressure.

It is demonstrated that severe dysfunction occurs in the myocardial segment supplied by a critically stenosed coronary artery during hypotension, while in contrast an increase in coronary perfusion pressure (to the extent used in this experimental model) is not detrimental to regional myocardial function. If the results of these experiments are applied to clinical practice, it appears to be of primary importance to maintain normal blood pressure in patients with ischaemic heart disease, and it may even be preferable to increase the blood pressure slightly during the peri-operative period.

Animals↗
PubMed1985

Myocardial ischaemia during tachycardia--not due to an increase in myocardial oxygen demand.

It is generally believed that an increase in heart rate will be accompanied by an increase in myocardial oxygen demand (MVO2), but in a recent publication this concept has been challenged; we present data supporting the view that an increase in heart rate is not necessarily accompanied by an increase in MVO2. Our data are based on studies on dogs in five phases: (a) normal coronary arteries; (i) with normal heart rate; (ii) with tachycardia induced by a pacemaker; and (iii) with normal heart rate; and (b) with a constricted left anterior descending coronary artery: (i) with normal heart rate; and (ii) with induced tachycardia. MVO2 remained unchanged both per beat and per unit of time. Neither global nor regional myocardial function in the area supplied by the constricted artery changed during tachycardia. The reason for myocardial ischaemia should therefore not be attributed to an increase in MVO2 if the diameter of the heart is not increased, and attention should rather be focused on inadequate diastolic perfusion time and possible redistribution of blood from the potentially ischaemic zone.

Animals↗
PubMed1985

Severe hypoxemia due to shunting through a patent foramen ovale: a correctable complication of right ventricular infarction.

A patient with recent inferior myocardial infarction with right ventricular involvement developed severe hypoxemia unresponsive to 100% oxygen. Contrast two-dimensional echocardiography revealed right to left shunting through an aneurysmal fossa ovalis with a patent foramen ovale. This was confirmed by cardiac catheterization. Surgical closure of the defect was probably life-saving. This case report illustrates that right to left shunting through a foramen ovale should be considered in the differential diagnosis of hypoxemia in patients presenting with inferior myocardial infarction.

Aged↗
PubMed1984

Typing scheme for Clostridium difficile: its application in clinical and epidemiological studies.

Epidemiological studies of Clostridium difficile diarrhoeal disease have been hindered by the lack of a typing scheme for this organism. A typing method based on the incorporation of sulphur-35-labelled methionine into cellular proteins and their separation by sodium dodecylsulphate/polyacrylamide gel electrophoresis showed clear pattern differences between strains, and nine distinct groups within the C difficile species were established. 98% of 250 clinical strains derived from four hospitals were typable. Group X was the commonest group and was associated with outbreaks of pseudomembranous colitis and antibiotic-associated colitis in two hospitals. Groups A-D were isolated predominantly from mothers and newborn infants. In outbreaks of antibiotic-associated colitis in oncology and orthopaedic wards the same strains, group X and group E, respectively, were isolated from patients and their environment, providing strong evidence of cross-infection between patients and of hospital acquisition of C difficile.

Adult↗
PubMed1984

Effect of hypoxia on the normal and ischemic myocardium.

This study investigated the effect of hypoxia on global and regional myocardial function in the normal heart and in the heart with a critically constricted coronary artery. Eight dogs under halothane anesthesia were subjected to progressive degrees of hypoxia while global and segmental heart function as well as general hemodynamics were evaluated. In the control phase of the experiment, the coronary circulation was undisturbed. A decrease in the inspired oxygen fraction from 0.3 to 0.1 was associated with significant increases in the heart rate, cardiac output, left ventricular minute work and coronary blood flow, and significant decreases in systemic vascular resistance. regional myocardial function (measured by endocardial fiber shortening) did not change. In dogs with a critical constriction applied to the left anterior descending coronary artery (LAD), hypoxia significantly increased heart rate and decreased stroke volume. Indices of global myocardial function did not change, but regional function in the area supplied by constricted LAD was depressed during severe hypoxia. This study implies that measured indices of global heart function bear little relation to regional function when a compromised segment of the myocardium is subjected to hypoxia.

Animals↗
PubMed1984

A grass roots approach to developing inpatient nursing unit work groups.

The change has taken three years. Many obstacles (attitudes, scheduling, philosophical differences, etc.) had to be overcome. The unit needed to develop its own autonomy and culture. The head nurse found it necessary to relinquish some control and the clinical nurses, in turn, had to determine manageable versus unmanageable problems. Risks were involved on every level from clinical nurses to the Director of Neuroscience Nursing, but all responded with trust and commitment to nursing and to the organizational goals. The unit was fortunate in a number of ways during the implementation of the work groups. It was advantageous to have a consultant who continually made the head nurse and group leaders look at the unit as a part of a total organization. The many "buts" that were interjected when comparing/contrasting nursing with other professions were refuted. It became apparent that the majority of nurses were fully aware that the profession involves working 24 hours a day, seven days a week including holidays. For the most part, the new graduate understands that hands on care includes such tasks as changing incontinent patients, making beds, and lifting and turning patients. Nursing also means intangible rewards in serving patients who need care. For nurses on our unit, what needed to be changed was the idea that a nurse has little or no control over the work life on a unit. If indeed nurses are committed to nursing, it is up to them, with appropriate support, to identify and alter the aspects of the job which are unsatisfactory.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1984

Identification of large cell undifferentiated tumours in lymph nodes using leucocyte common and keratin antibodies.

A total of 43 cases undifferentiated large cell tumours presenting in lymph nodes were stained by immunoperoxidase techniques using antibodies against keratin and a leucocyte-associated glycoprotein. In 26 cases diagnosed histologically as metastatic carcinoma, staining with the keratin antibody suggested a squamous cell origin in 11 cases. This was supported by microscopic observation of intracellular filaments in seven cases. In 15 patients in whom the original diagnosis was uncertain, a definite diagnosis was possible in all cases following immunoperoxidase staining with the two antibodies and most of these proved to be large cell lymphomas. In two cases a potentially major diagnostic error was detected. It is suggested that the staining of undifferentiated human neoplasms using combinations of antibodies reactive with epithelial and lymphoid cells should result in much greater diagnostic accuracy in the field of large cell tumours presenting in lymph nodes.

Adolescent↗
PubMed1984

The effect of hypocapnia on coronary blood flow and myocardial function in the dog.

The effect of hypocapnia on global and regional myocardial function and coronary blood flow (CBF) was studied in dogs anesthetized with halothane before and after critical constriction of the left anterior descending (LAD) coronary artery. Coronary blood flow decreased 29% (P less than 0.05) when hypocapnia was induced in dogs with a normal LAD artery. Critical constriction reduced CBF by 42% (P less than 0.05). In the critically constricted LAD artery, hypocapnia did not reduce CBF. During hypocapnia and with a normal LAD artery, oxygen extraction by the myocardium increased 16% (P less than 0.01) and oxygen tension in the coronary sinus was reduced by 19% (P less than 0.001). After critical constriction of the LAD, hypocapnia was associated with an increase in oxygen extraction of 14% (P less than 0.01) and the coronary sinus oxygen tension was reduced by 21% (P less than 0.001). CBF of the left circumflex coronary artery (LC) increased 36% (P less than 0.05) after critical constriction to the LAD when compared with control values of the preconstriction phase. However, LC flow did not change during hypocapnia when critical stenosis had been applied to the LAD artery. Although oxygen supply (product of CBF and arterial oxygen content) to the myocardium was reduced during hypocapnia, regional myocardial function did not change from control values. Regional function was similarly maintained during hypocapnia and critical constriction of the LAD.

Anesthesia, General↗
PubMed1984

[Non-Hodgkin's malignant lymphoma with cervicofacial expression. Modulation of the radiotherapy-chemotherapy combination according to the cytological class].

An analysis was conducted in March 1983, after a mean follow up of 40 months, of cases of cervicofacial stages I and II non-Hodgkins malignant lymphoma in 3 children and 41 adults (mean age: 51 years, range: 6-90 years) treated between 1969 and March 1981. According to the Working Formulation malignancy was low in 4 cases, intermediate in 24 and high in 13; 3 cases could not ne classified retrospectively. Cytologic classification showed 13 of class 1 of low malignancy, 7 of class 2 of high malignancy with leukemic potential, and 16 of class 3 of high malignancy with a course leading to tumor formation. The cavum was involved in 10 cases, the tonsils in 9, the parotids in 1, the uvula in 1, isolated cervical adenopathies in 14, multiple unilateral adenopathies in 3 and bilateral cervical adenopathies in 5 cases. Therapy varied according to the series: in the first series (1969-1975) the 23 cases were treated by radiotherapy alone (40-55 Gy). In the second series (1976-1981) of 21 cases, chemotherapy was given as a function of the cytologic class: prophylactic chemotherapy for 6 months after radiation for classes 1 and 2, initial chemotherapy for 6 weeks, cerebral radiation and methotrexate intrathecally, and maintenance chemotherapy for 3 months in class 3. The failure rate for radiated zones was identical in the 2 series (less than 10%). Adjusted 5-year survival rate was 60% for series 1 against 70% for series 2 (p = 0.9), and adjusted remission rate was 43% against 64% (p = 0.8).

Adolescent↗
PubMed1984

Immunologic and inflammatory responses during pregnancy.

Rheumatoid arthritis commonly improves markedly during pregnancy, and it has been suggested that this reflects a decrease in immunological or inflammatory effector mechanisms. We elicited a delayed type hypersensitivity (DTH) response to Burro RBC, by injection of primed lymphocytes and antigen into murine footpads. The swelling induced in footpads of pregnant mice was not significantly different from that seen in controls, nor was the response to a non-immunologic inflammatory stimulus, carrageenan, decreased in pregnant mice. On the other hand, a defect in the priming or induction phase of a primary DTH response was impaired in pregnancy, but whether this is relevant to the pregnancy induced remission of rheumatoid arthritis remains to be demonstrated.

Animals↗
PubMed1983

Ion-exchange high-performance liquid chromatography of oligodeoxyribonucleotides using formamide.

The superiority of buffer systems containing formamide for the ion-exchange high-performance liquid chromatographic separation of oligodeoxyribonucleotide mixtures generated in solid-phase syntheses is illustrated. The resolutions achieved are compared to those achieved with the same mixtures in other eluting solvents. The use of formamide systems is recommended for oligodeoxyribonucleotide purification in general and is particularly valuable where the oligonucleotide of interest is highly self-complementary and/or rich in deoxyguanosine residues.

Chromatography, High Pressure Liquid↗
PubMed1983

Promoter mutations that allow nifA-independent expression of the nitrogen fixation nifHDKY operon.

The nifHDKY operon of Klebsiella pneumoniae encodes for structural polypeptides of nitrogenase and requires the nifA gene product for transcription. Mutations that allow transcription of the nifHDKY operon in absence of the nifA gene product were characterized in plasmids containing the regulatory region of nifHDKY and nifH fused in phase to lacZ. beta-Galactosidase activity served as a measure for nifH expression. Most mutations were located in the nif regulatory region and included insertion sequence 2 (IS2) insertions, a sequence duplication, and a base substitution. In Escherichia coli, beta-galactosidase activity expressed from the mutant plasmids in the absence of nifA was 6-30% of the nifA-activated, parental level. Expression from most mutant plasmids was further increased by nifA. In K. pneumoniae, IS2-containing plasmids expressed low levels of beta-galactosidase and responded poorly, if at all, to activation by nifA, whereas expression from other mutant types was similar to that observed in E. coli. Nucleotide sequence analysis of two mutants indicated that sequences within 41 base pairs upstream to the nifH coding sequence were involved in nif-specific regulation. The results suggest that an inverted repeat element in this region, which could theoretically form a cruciform structure in the DNA, is involved in the transcriptional control of the nifHDKY operon.

Bacterial Proteins↗
PubMed1983

Metabolic studies with 'Nutrauxil', an enteral feed preparation.

A metabolic study was carried out in 6 patients requiring enteral feeding to investigate the effectiveness and tolerance of 'Nutrauxil', a ready-made liquid nutritional preparation, over a period of 8 days. The results of anthropometric and laboratory measurements, made initially and at the end of two 4-day periods, showed that the basic provision of 2000 kcal and 60 g protein per day with 'Nutrauxil' maintained patients in metabolic, electrolyte and nitrogen balance. No adverse effects were noted and the preparation was easy to administer. It was concluded that 'Nutrauxil' compared favourably with other enteral feed preparations with respect to its nutritional effectiveness on clinical, biochemical and economic grounds.

Aged↗