Search PubMed⌕ Search

Biomedical subjects

P Jacobs

Publications and source records attributed to P Jacobs.

At least 199 records · Page 11Linked to original sources
PubMed1993

The implications of an epidemiological mistake: a community's response to a perceived excess cancer risk.

OBJECTIVES: The response of community residents to a perceived cancer excess may include changes in attitude, health-related behavior, and property values. In 1986, a cancer agency conducted a study of cancer incidence (1979 to 1983) in two suburbs of Edmonton, Alberta, and reported elevations on the order of 25% over expected for most sites. Reanalysis of these data several months later revealed an error. Correction brought the rates into line with Alberta as a whole and with other communities surrounding Edmonton. METHODS: We used public opinion trends and property value trends (during the period of concern) to study the two communities affected by the allegation of increased cancer risk. RESULTS: A survey of residents found significant differences at the time in health-related behavior and beliefs suggesting increased perception of personal, family, and community risk and modest changes in behavior. Real estate values in one community temporarily lost an average of $4000, or about 5% of total value, compared with a similar, adjacent housing market. CONCLUSIONS: The perception of an elevated cancer risk, in the absence of a true risk, may have a substantial negative effect on the affected community, both psychologically and economically.

Adult↗
PubMed1993

Sterrad Sterilization System: a new technology for instrument sterilization.

The Sterrad Sterilization System by Advanced Sterilization Products (ASP) exploits the synergism between peroxide and low temperature gas plasma (an excited or ionized gas) to rapidly destroy microorganisms (Figure 1). At the completion of the sterilization process based on this technology, no toxic residues remain on the sterilized items. The technology is particularly suited to the sterilization of heat and moisture sensitive instruments since process temperatures do not exceeded about 50 degrees C (140 degrees F) and sterilization occurs in a low moisture environment. Total process time is about one hour. The efficacy of the process has been demonstrated against a broad spectrum or microorganisms and on a large number of substrates used in medical instruments.

Equipment Contamination↗
PubMed1993

Serial measurements of circulating tissue plasminogen activator and fibrin(ogen) degradation products predict outcome in gestational proteinuric hypertension.

Gestational proteinuric hypertension (GPH), a major cause of maternal death, may be characterised by hypertension and proteinuria alone or may progress to disturbed coagulation and multiorgan failure. Since the condition can only be reversed by termination of pregnancy, there is a need for reliable indicators of severity. We found circulating levels of tissue plasminogen activator (tPA) (27.98 +/- 2.12 v. 7.17 +/- 0.81 ng/ml, mean +/- SEM), fibrin(ogen) degradation products (FDP) (7.55 +/- 1.99 v. 1.92 +/- 0.47 micrograms/ml) and fibronectin (221 +/- 15.2 v. 120 +/- 15.2 micrograms/ml) to be significantly increased in 21 patients with severe GPH when compared with 21 normotensive, age- and gestational age-matched pregnant controls. More importantly, patients who developed severe GPH showed a progressive increase in tPA and FDP levels with time. This was in contrast to patients who had hypertension and proteinuria alone, in whom tPA and FDP concentrations did not increase. Parallel measurements did not reveal a fall in platelet count or an increase in urinary protein excretion in patients who subsequently progressed to severe disease. Our findings may be of assistance to clinicians faced with the need to prolong pregnancy in patients with GPH in order to ensure fetal viability.

Enzyme-Linked Immunosorbent Assay↗
PubMed1993

Geographical distribution of acute lymphoblastic leukaemia subtypes: second report of the collaborative group study.

Childhood acute lymphoblastic leukemia (ALL) T and B precursor subtypes have been identified by standardised immunophenotyping in different geographic and ethnic settings. Comparison of the relative frequencies and estimated incidence rates of the major subtypes indicates very similar values, with the striking exception of black childhood populations in Africa in which there appears to be a significant and selective deficit in the incidence of the common (B-cell precursor) subset of ALL. There is suggestive evidence for a similar bias in ALL subtypes in South Africans of mixed ethnic origin and in Mapuche Indians from Chile. Several interpretations of these data are possible but the one favoured attributes these differences primarily to socio-economic factors and patterns of infection in infancy.

Adolescent↗
PubMed1993

Abnormal peri-operative haemorrhage in asymptomatic patients is not predicted by laboratory testing.

The pre-operative identification of individuals at high risk of bleeding during major elective surgery is obviously important. Extensive haemostatic screening is, however, expensive and may be inappropriate in low-risk groups. Accordingly, we undertook two studies to determine whether it could be justified in patients without a history of abnormal bleeding. In the first of these, 45 of 159 patients were excluded because of aspirin ingestion and a further 3 because of positive bleeding history so that prothrombin time, activated partial thromboplastin time, bleeding time and platelet count were measured in 111 asymptomatic patients about to undergo major surgery. A single patient had mild thrombocytopenia, and 8 had a prolonged partial thromboplastin time; none showed abnormal peri-operative haemorrhage. In the second study, over a 4-month period, 49 patients out of 1,872 required larger peri-operative blood transfusions than anticipated; on investigation, none of these patients was shown to have disturbances in haemostatic mechanism, the transfusion having been indicated for technical reasons. Patients undergoing elective surgery should be asked about medication and previous bleeding and if they have no history thereof and a physical examination is negative, pre-operative screening for coagulation defects would appear to be unnecessary.

Aspirin↗
PubMed1993

Factors affecting the acquisition of Plagiorchis noblei (Trematoda: Plagiorchiidae) cercariae by black fly (Diptera: Simuliidae) larvae and the effect of metacercariae on host survival.

Larvae of 4 species of black flies, Prosimulium mixtum, Simulium vittatum, S. decorum and Stegopterna mutata, were exposed in the laboratory to cercariae of the digenean Plagiorchis noblei in flowing water. Prevalence and intensity of infection of all species varied directly with exposure intensity and decreased with increasing water velocity; prevalence increased with larval size. Infection levels for P. mixtum were higher than for the 3 other species. Mortality among infected larvae of all species was 3 times that of controls. Exposure of black fly larvae to P. noblei cercariae may adversely affect their survival.

Animals↗
PubMed1992

A reinvestigation of thirty three fragile(X) families using probe StB12.3.

We have reinvestigated 33 fragile X families using probe StB12.3. In 31 families the affected individual showed an insert while in 2 families no insert was detected. The insert fell into two size categories: small (less than 0.5 kb); and large (greater than 0.6 kb) accompanied by methylation of an EagI site. All individuals of either sex having a small insert were fra(X) negative and intellectually normal, while all males having a large insert were fra(X) positive and intellectually impaired. Females having a large insert were either fra(X) positive or negative and either intellectually normal or impaired. No new mutation was found. All daughters of males with a small insert had a small insert; females with a large insert produced males and females who had a large insert, while females with a small insert had offspring with either a large or a small insert. However, females with a small insert tended to fall into one of two categories: either they had only children with a small insert or only children with a large insert, there being only one exception to this rule. We found four unexpected small inserts, two in unrelated spouses and two in female carriers who proved to be compound heterozygotes, indicating that they had inherited an insert from both their parents. These observations suggest that individuals with a small insert must be not uncommon in the general population.

DNA Probes↗
PubMed1992

Splenectomy in the chronic myeloproliferative syndromes. A retrospective risk-versus-benefit analysis.

The effect of splenectomy on the course of the chronic myeloproliferative syndromes was retrospectively analysed and compared in 96 patients who underwent this procedure and 195 who did not. The operation had a 4% mortality and a 47% morbidity rate, mainly attributable to haemorrhage, infection and respiratory complications. While splenectomy conferred benefit in certain selected cases with hypersplenism, there was no significant overall improvement in the postoperative haematological values and no influence on the rate of blastic transformation. Splenectomy did not improve survival in the group as a whole, or in any subset (P greater than 0.5). In the non-splenectomy group, only a minority of patients experienced massive progressive splenomegaly and in most individuals the spleen size varied little from the time of presentation to death. Splenectomy in patients with the chronic myeloproliferative syndrome carries a significant mortality and has a high morbidity, does not reduce the rate of blastic transformation and has no influence on survival. The majority of patients on conventional therapy do not experience the discomfort of massive splenomegaly during the course of their disease and the routine use of this operation is inappropriate.

Adolescent↗
PubMed1992

Antilymphocyte globulin and high-dose methylprednisolone improve survival in patients with aplastic anaemia without additional financial costs.

The cost-benefit ratio in the treatment of aplastic anaemia with antilymphocyte globulin (ALG) combined with high-dose methylprednisolone (HDMP) was retrospectively compared with supportive palliative treatment alone. Over a 4-year period financial cost, response rate, survival and performance status was documented in 26 consecutive patients receiving this regimen. Outcome was favourable in 69% (group 1; N = 18) and in 13 comprehensive expenditure data were available. In the remainder (group 2; N = 8) treatment failed and they were considered to be the equivalent of a no-treatment population. Here hospital charges were analysed both with and without inclusion of ALG and HDMP. Over the 1-year study period, no significant difference in the median expenditure was found between group 1 at R19 281 (range R35 657-13 379) and group 2 at R18 522 (range R22 449-16 951). The median number of admissions for group 1 was one and for group 2 three, requiring a median of 19 and 20 days of hospitalisation respectively. At the end of the 1-year study period 19 of 26 patients were alive (73%), 69% having responded. At this time, 16 of the 18 patients in group 1 had returned to their previous occupations, but this had not been possible for any of the 8 in group 2. In suitably selected patients who do not have an allogenic bone marrow transplant option the expenditure on ALG and HDMP is both medically and economically sound and the combination can be recommended as a valuable treatment option.

Anemia, Aplastic↗
PubMed1992

Method for the safe and rapid pretransfusion warming of stored blood: an in vitro and in vivo evaluation of a radiofrequency (RF) instrument.

Inadvertent hypothermia due to massive infusion of stored blood can be prevented by pretransfusion warming. One approach is the heating of individual packs by means of electromagnetic conduction, which is a method safely used over the last 25 years. The prototype instrument, which has now been re-engineered, can effectively raise the temperature of a unit of blood to approximately 33 degrees C in less than 3 minutes. Using this new model, we found, in vitro, a modest increase in free plasma haemoglobin, but this was not accompanied by any change in potassium or lactic dehydrogenase levels and the mean red cell fragility was unaltered. In vivo, the survival of autologous red cells that had been stored for 33 days and then infused as a concentrate, having a mean haematocrit of 0.60, was measured at 24 hours and 21 days. Each donor acted as his own control. In paired studies, pretransfusion radiofrequency heating was shown to have no deleterious effect when compared to measurements using the unwarmed blood pack. It is concluded that this method can be recommended as safe.

Adult↗
PubMed1992

Molecular cloning, characterization and purification of ornithine carbamoyltransferase from Mycobacterium bovis BCG.

A genomic library of Mycobacterium bovis BCG has been constructed by cloning DNA partially digested with Sau3A into the Escherichia coli expression vector pAS1. The gene coding for ornithine carbamoyl-transferase (EC.2.1.3.3; OTCase), hereafter referred to as argF, was isolated from the library by complementation of a double argF-argI mutant of E. coli and its sequence was determined. The translation initiation codon used, GTG, was identified by comparing the amino acid sequence deduced from the gene with the N-terminal sequence of the corresponding purified protein. On this basis, the M. bovis BCG OTCase monomer consists of 307 amino acid residues and displays about 44% identity with other OTCases, the most closely related homologue being the anabolic enzyme of Pseudomonas aeruginosa. The native enzyme has an estimated molecular mass of 110 kDa, suggesting a trimeric structure as is the case for most of the anabolic OTCases known from various organisms.

Amino Acid Sequence↗