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Biomedical subjects

R Jackson

Publications and source records attributed to R Jackson.

At least 37 records · Page 2Linked to original sources

Translational regulation. Y the message is masked?

Much mRNA in Xenopus oocytes is translationally dormant for months until meiotic maturation and fertilization. This masking has been found to be coupled to transcription and mediated by the Y-box protein FRGY2.

Animals

The role of case management within a community support system: partnership with psychosocial rehabilitation.

The Strengths model of team case management was assessed relative to an existing high quality psychosocial rehabilitation program that informally provided many services typical of case management (e.g., service linkage, monitoring, and consumer advocacy). The experimental evaluation triangulated consumer and family member responses with mental health professional reports and consumer records of hospitalization and crisis center contacts. An analysis of data from these four sources revealed that one year after full program implementation, consumers who received case management in conjunction with psychosocial rehabilitation functioned at a higher level of competency and experienced significantly lower psychiatric symptomatology than consumers who received only psychosocial rehabilitation. Implications for the successful integration of case management into an existing community support program are discussed.

Activities of Daily Living

The epidemiology of Mycobacterium bovis infections.

Mycobacterium bovis has an exceptionally wide host range, but until recent years there was little concern about infection in species other than cattle and man. Diversification of farming enterprises has led to cognizance of the need for control in other domestic animals, notably deer. There has also been recognition that self-maintaining infection is present in wildlife hosts in some countries--notably the European badger in the United Kingdom and Ireland, the Australian brush-tailed possum in New Zealand, and various species of ungulates in limited areas of a number of countries. Although transmission of M. bovis can occur by a number of different routes, control measures imposed on cattle and to a lesser extent on other species have reduced a number of the routes to insignificance. Hence the vast preponderance of transmission within host species is now by the airborne route, and predominantly between species as well. Transmission of infection from badgers to cattle may be an exception, with evidence remaining equivocal about the relative importance of pasture contamination by excretion in badger urine and airborne transmission. In general, contamination of feed and pasture appears to be unimportant in transmission of the disease, because survival times of infective doses of organisms on fomites are relatively short under realistic conditions and because animals are not commonly exposed to a dose high enough to be infective by the alimentary route. Infection through the oro-pharyngeal mucous membrane may be significant, although the infective dose for this route is not known. While many species of animals can become infected with M. bovis, only a few act as maintenance hosts and the rest are spillover hosts in which infection is not self-maintaining. With the exception of cattle and deer, other species have become maintenance hosts only within part of their ecological range. For both badgers and possums, maintenance of infection within a local population is due to pseudo-vertical transmission from mother to young, and horizontal transmission linked to breeding activity. Transmission from possums to domestic animals appears to occur mainly during atypical behavioural interactions between the species, and this may well be important for badgers as well. Difficulties in controlling the disease adequately in domestic animals generally result from administrative problems since the necessary technical procedures are available and have been shown to be effective. Where there is interplay between infection in wildlife and domestic animals, eradication of the disease becomes impractical.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals

Clinical decision rule for knee radiographs.

The objective of this study was to develop a decision rule for ordering x-rays in knee injuries. Phase I was a retrospective chart review of 201 consecutive patients receiving knee radiographs in the emergency department in a 10-month period. Logistic regression was performed on 11 clinical indicators to develop a clinical decision rule. Phase II was a prospective validation study on 133 consecutive patients with knee injuries. All patients received radiographs to validate the decision rule. Sensitivity, specificity, and misclassification rate were calculated. Logistic regression analysis found that a fall or blunt trauma mechanism yielded a logistic regression sensitivity of 92%, specificity of 57%, with a false-negative rate of 0.9%. The addition of inability to ambulate and age (younger than 12 or older than 50 years of age) yielded a sensitivity of 92% with a specificity of 63%. The prospective study found the combination of fall or blunt trauma with either inability to ambulate or age (younger than 12 to older than 50 years of age) was 100% sensitive, with a specificity of 79%. The misclassification rate was 20%. Using this decision rule, the number of x-rays taken could have been reduced by 78%. A larger multicenter validation study of this knee radiograph decision rule is needed before widespread clinical usage.

Acute Disease

The effect of fluoride therapy on blood chemistry parameters in osteoporotic females.

To determine the potential adverse effects, if any, of long-term fluoride ingestion in humans, samples were collected from 25 adult females taking daily doses of fluoride (mean, 23 mg elemental F) for the treatment of osteoporosis and from 38 osteoporotic female controls. Patients in the fluoride group had been receiving therapy for approximately 18 months with a mean duration of 4.2 years and had serum fluoride values of at least 10 mumol/l. Laboratory analyses for fluoride were conducted on plasma, urine and drinking water samples collected from each panelist. Blood was also collected for blood chemistry analyses and plasma lymphocytes were examined for the frequency of sister chromatid exchange (SCE). Plasma and urine fluoride levels were significantly different between the two groups, while water fluoride was not. The SCE frequency, a measurement of potential genotoxicity, did not differ between the two groups. Of the blood chemistry parameters measured, albumin, alkaline phosphatase, sodium, chloride, the albumin/globulin (A/G) ratio, indirect bilirubin, lactate dehydrogenase (LDH), and gamma-glutamyl transferase (GGT) were found to be significantly different between the two groups (P < or = 0.05). However, none of the mean group values were outside stated normal ranges for any of these parameters. We conclude that the risk of developing adverse systemic effects from the ingestion of fluoride, at dosages and for a duration comparable with that of our panel, is minimal.

Aged

Intestinal flora of the medicinal leech Hirudinaria manillensis.

Medicinal leeches are widely used to treat venous congestion in microvascular surgery. Aeromonas hydrophila infection, following application of the leech species Hirudo medicinalis, is a recognized complication. Administration of antibiotics directed at Aeromonas has been successful in minimizing complications of infection from this organism. A different leech species, Hirudinaria manillensis, has recently been introduced for microsurgical use. A study of the enteric content of 30 of these leeches showed that Aeromonas hydrophila was isolated in only 20 percent of animals, while the majority of remaining positive cultures were single and mixed gram-negative rods. All organisms isolated were sensitive to current recommended coverage for Aeromonas hydrophila. This study suggests that the enteric flora of different leech species may be variable and should be carefully characterized, to direct appropriate prophylactic therapy prior to release of new species for clinical use.

Aeromonas

Low mortality rate in adult respiratory distress syndrome using low-volume, pressure-limited ventilation with permissive hypercapnia: a prospective study.

OBJECTIVES: To evaluate the outcome in patients with severe adult respiratory distress syndrome (ARDS) managed with limitation of peak inspiratory pressure to 30 to 40 cm H2O, low tidal volumes (4 to 7 mL/kg), spontaneous breathing using synchronized intermittent mandatory ventilation from the start of ventilation, and permissive hypercapnia without the use of bicarbonate to buffer acidosis. Also, to compare hospital mortality rate with that predicted by the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system and the "ventilator score." SETTING: A ten-bed general intensive care unit in a university hospital. DESIGN: Prospective, descriptive study. PATIENTS: Fifty-three patients with severe ARDS having a lung injury score of > or = 2.5. INTERVENTIONS: Data recording. RESULTS: The hospital mortality rate was significantly lower than that predicted by the APACHE II scores (26.4% vs. 53.3%, p = .004), even after correcting the latter for the effect of hypercapnic acidosis (26.4% vs. 51.1%, p = .008). The mortality rate increased with increasing number of organ failures, but was only 43% in patients with > or = 4 organ failures, 20.5% with < or = 3 organ failures, and 6.6% with only respiratory failure. The mean maximum PaCO2 was 66.5 torr (range 38 to 158 torr [8.87 kPa, range 5.07 to 21.07]), and the mean arterial pH at the same time was 7.23 (range 6.79 to 7.45). There was no correlation between the maximum PaCO2 or the corresponding pH and the total respiratory rate at the same time. No pneumothoraces developed during mechanical ventilation. CONCLUSIONS: These results lend further support to the hypothesis that limitation of peak inspiratory pressure and reduction of regional lung overdistention by the use of low tidal volumes with permissive hypercapnia may reduce ventilator-induced lung injury and improve outcome in severe ARDS. This hypothesis is supported by a large body of experimental evidence, which also suggests that ventilator-induced lung injury may result in the release of inflammatory mediators, and thus may have the potential to augment the development of multiple organ dysfunction. However, the hypothesis requires testing in a randomized trial as acute hypercapnia could potentially have some adverse as well as beneficial effects.

APACHE

Novel immunohistochemical localization of 28,000 molecular-weight (Mr) calcium binding protein (calbindin-D28k) in enterochromaffin cells of the human appendix and neuroendocrine tumors (carcinoids and small-cell carcinomas) of the midgut and foregut.

Calbindin-D28k is a highly conserved 28,000 (dalton) molecular-weight (Mr) calcium binding protein with broad tissue distribution, yet cell-type-specific expression predominantly in subpopulations of central and peripheral nervous system neurons, distal tubular cells of the kidney, and enteric neuroendocrine cells. A polyclonal antiserum against rat renal calbindin-D28k and a monoclonal antibody to calbindin-D28k purified from chicken intestine (clone CL-300) were used for immunohistochemical evaluation of formalin-fixed, paraffin-embedded tissues from multiple areas of the human small and large intestines and 93 primary neoplasms of the gastrointestinal tract (foregut, midgut, and hindgut derivatives) and the lung (foregut derivative). Calbindin-D28k immunostaining was obtained in a minority of enterochromaffin (neuroendocrine) cells, predominantly of the appendix and small intestine, as well as in autonomic neurons of the neural plexuses. Focal cytoplasmic Golgi-type staining was obtained with monoclonal antibody CL-300 in the appendiceal surface epithelium and dendritic macrophages confined to the appendiceal lymphoid follicles. Epithelial progenitor cells in enteric crypts and absorptive, goblet, and Paneth cells were calbindin-D28k negative, while no immunoreactivity was demonstrated in the mucosae of the colon and rectum. Calbindin-D28k staining was consistently detected in subpopulations of neuroendocrine phenotypes in midgut (appendiceal/ileal) and foregut (bronchial) carcinoids and small-cell carcinomas, but was absent in adenocarcinomas, squamous cell carcinomas, leiomyomas/leiomyosarcomas, schwannomas, and lymphomas. Our observations suggest that calbindin-D28k is a novel adjuvant neuroendocrine marker that is potentially useful in diagnostic tumor immunohistochemistry.

Adult

Primary versus proxy respondents: comparability of questionnaire data on alcohol consumption.

Questionnaire data on alcohol consumption obtained from primary respondents participating in a community-based case-control study of coronary heart disease were compared with similar data obtained from their next of kin. The primary respondents were men and women aged 25-64 years who were a representative sample of myocardial infarction cases (n = 58) and controls (n = 456) from the case-control study. The study was conducted in Auckland, New Zealand between 1986 and 1988. When alcohol drinking frequency was collapsed into five categories, exact agreement between primary respondents and next of kin was 64% for cases and 62% for controls. Agreement within one category (plus or minus) was 89% for both cases and controls. Tests of marginal homogeneity showed no evidence that next of kin systematically over- or underestimated the primary respondents' self-reported drinking frequency. With respect to the amount of alcohol drunk, mean differences between primary respondents and next of kin were small (mean difference: 2.25 g per day for cases; -0.77 g per day for controls), although there was considerable variability between individual pairs in the level of agreement. The findings suggest that studies which use proxy sources of data to assess alcohol drinking are unlikely to produce biased estimates of alcohol consumption at the aggregate level, particularly with regard to frequency measures.

Adult

Management of raised blood pressure in New Zealand: a discussion document.

A report to the National Advisory Committee on Core Health and Disability Support Services, New Zealand, on the management of raised blood pressure recommends that decisions to treat raised blood pressure should be based primarily on the estimated absolute risk of cardiovascular disease rather than on blood pressure alone. In general, patients with a blood pressure of 150-170 mm Hg systolic or 90-100 mm Hg diastolic, or both, should be given treatment to lower blood pressure if the risk of a major cardiovascular disease event in 10 years is more than about 20%. The results of clinical trials indicate that, at this level of absolute risk, 150 people would require treatment to reduce the annual number of cardiovascular events by about one. Implementation of these recommendations may result in a smaller proportion of people aged under 60, particularly women, receiving treatment but an increased proportion of older people treated. In the absence of specific contraindications, low dose diuretics and low dose beta blockers should be considered for first line treatment, since for only these drug groups is there direct evidence of reduced risk of stroke and coronary disease in people with raised blood pressure.

Blood Pressure

Complete hydatidiform mole coexistent with a twin live fetus: clinical course of four cases with complete cytogenetic analysis.

Twin gestations can occur in which one twin is a normal gestation (46 chromosomes: 23 maternal and 23 paternal origin) and in which the other twin is a complete hydatidiform mole (46 chromosomes all of paternal origin). Case reports of four such combined pregnancies that presented to a single institution are provided. All cases had documentation of clinical information, cytogenetic analysis, and fetal and placental pathology. Three of the four pregnancies were terminated for medical indications despite information documenting the presence of a normal fetus. All three of these patients required subsequent chemotherapy. The fourth case was followed conservatively and resulted in the birth of a normal infant at 38 weeks gestation. We speculate that the factors that led to the need for termination of the pregnancy (aggressive growth of trophoblast) may predict the need for further therapy. A true assessment of the antenatal and malignant sequelae risks associated with these rare gestations awaits the collection of a larger series of patients.

Adult