Search PubMed⌕ Search

Biomedical subjects

M Jong

Publications and source records attributed to M Jong.

7 recordsLinked to original sources
PubMed1999

Increased clearance explains lower plasma levels of tissue-type plasminogen activator by estradiol: evidence for potently enhanced mannose receptor expression in mice.

Several clinical studies have demonstrated an inverse relationship between circulating levels of estrogen and tissue-type plasminogen activator (t-PA). The present study was designed to test the hypothesis that estrogens lower plasma levels of t-PA by increasing its clearance from the bloodstream. 17alpha-Ethinyl estradiol (EE) treatment resulted in a significant increase in the clearance rate of recombinant human t-PA in mice (0.46 mL/min in treated mice v 0. 32 mL/min in controls; P <.01). The clearance of endogenous, bradykinin-released t-PA in rats was also significantly increased after EE treatment (area under the curve [AUC], 24.9 ng/mL. min in treated animals v 31.9 ng/mL. min in controls; P <.05). Two distinct t-PA clearance systems exist in vivo: the low-density lipoprotein receptor-related protein (LRP) on liver parenchymal cells and the mannose receptor on mainly liver endothelial cells. Inhibition of LRP by intravenous injection of receptor-associated protein (RAP) as a recombinant fusion protein with Salmonella japonicum glutathione S-transferase (GST) significantly retarded t-PA clearance in control mice (from 0.41 to 0.25 mL/min; n = 5, P <.001) and EE-treated mice (from 0.66 to 0.35 mL/min; n = 5, P <.005), but did not eliminate the difference in clearance capacity between the 2 experimental groups. Similar results were obtained in mice in which LRP was inhibited via overexpression of the RAP gene in liver by adenoviral gene transduction. In contrast, administration of mannan, a mannose receptor antagonist, resulted in identical clearances (0.22 mL/min in controls and 0.24 mL/min in EE-treated mice). Northern blot analysis showed a 6-fold increase in mannose receptor mRNA expression in the nonparenchymal liver cells of EE-treated mice, whereas the parenchymal LRP mRNA levels remained unchanged. These findings were confirmed at the protein level by ligand blotting and Western blotting analysis. Our results demonstrate that EE treatment results in increased plasma clearance rate of t-PA via induction of the mannose receptor and could explain for the inverse relationship between estrogen status and plasma t-PA concentrations as observed in humans.

Animals↗
PubMed1998

Tuberculosis: finding a community solution.

The Tuberculosis Surveillance Project set out to gain community and health care worker support for and participation in the development and implementation of a tuberculosis control program which would address the high incidence of tuberculosis in Innu and Inuit communities in Labrador. The underlying principle of this project is that a tuberculosis control program must have the support of both the communities and the health care workers if it is to succeed. A three-person tuberculosis steering committee, with representation from the Innu Nation, the Labrador Inuit Association, and the Labrador Health Services Board, supervised initial tuberculosis data collection and analysis and workshop planning. Community Health Representatives, community physicians, and community nurses participated in a workshop to develop a tuberculosis protocol for the region. In addition, community tuberculosis control strategies were developed in workshops in each community in an effort to ensure community and health care worker support for the protocol and tuberculosis control in its broadest sense. This project illustrates how partnerships between communities and health care workers can be achieved. Future tuberculosis incidence rates will be used to evaluate the effectiveness of the partnership.

Adolescent↗
PubMed1989

Epidemiologic features of hepatitis B virus infection in northern Labrador.

We studied the epidemiologic features of hepatitis B virus (HBV) infection in northern Labrador to determine the prevalence of the infection and to obtain a database to develop a vaccination strategy. The study population included seven communities in which five ethnic groups were represented: Inuit, Innu, mixed Inuit and European ancestry ("settler"), nonnative/nonsettler transient population ("white") and people of Innu-white or Innu-Inuit origin ("mixed"). Blood samples from 2156 people (62% of the area residents) were tested for antibody to HBV core antigen (anti-HBc), HBV surface antigen (HBsAg), HBV e antigen (HBeAg), anti-HBc IgM and antibody to the surface antigen (anti-HBs). The overall crude prevalence rate of HBV seromarkers was 14.7% and the HBsAg carrier rate at least 3.2%; the rates were highest for Inuit (26.4% and 6.9% respectively), followed by settler (10.0% and 1.9% respectively) and Innu (7.6% and 0.4% respectively); the white and mixed groups had the lowest overall rates (2.5% and 3.3% respectively). Although the overall prevalence rates were about the same for the two sexes, the HBsAg carrier rate was higher in males (male:female ratio 1.6:1.0). No HBV carriers were positive for HBeAg or anti-HBc IgM antibody. The rate of exposure to HBV was 4% for those below the age of 20 years and reached a peak for those aged 45 to 54 years (85% for Inuit, 40% for settlers and 37% for Innu). There was also a wide variation in the age-standardized prevalence rates (0% to 27.9%) among the ethnic groups in the seven communities surveyed.

Adolescent↗
PubMed1986

Endoscopic haemostasis of the upper gastrointestinal tract.

The realm of endoscopy has gone from that of diagnosis to that of diagnosis and therapy. Therapeutic endoscopy is a rapidly advancing frontier in the field of gastroenterology. Its use in securing haemostasis has recently flourished. Considerable progress has been made. Various experimental techniques have been tried and found lacking, while others, such as laser photocoagulation, electrohydrocoagulation and endoscopic sclerotherapy, are proving to be very useful. The mortality for upper gastrointestinal bleeding has remained high for decades, despite recent advances in medicine. This may be related to the shift in the population toward the older age group. Recent advances in endoscopic haemostasis seem to be showing promise in improving survival rates. This is a result of improved recognition of risk factors, including the stigmata of recent haemorrhage, of early surgical intervention in the elderly, and of the ability to reliably secure haemostasis endoscopically. This chapter gives an account of the various techniques of endoscopic haemostasis and explains the numerous controversies through the discussion of selected experimental and clinical trials.

Clinical Trials as Topic↗
PubMed1985

Occurrence of Cryptosporidium oocysts in fecal samples submitted for routine microbiological examination.

During a 7-month period, 2,252 fecal samples submitted for routine microbiological examination from 1,621 patients were screened for Cryptosporidium oocysts by the auramine staining method with Kinyoun acid-fast stain as the confirmatory stain. Cryptosporidium oocysts were detected in fecal samples from 19 (1.2%) patients, 18 of whom had gastroenteritis. Diarrheic stools from 14 of these 18 patients were negative for the usual enteropathogens but contained the oocysts in moderate to large numbers. Although Cryptosporidium oocysts were found in patients of all ages, they occurred slightly more frequently in infants and children than in the rest. Cryptosporidium species was one of the common enteropathogens identified in fecal samples submitted for routine parasitological examination during the period of the survey and was second only to Giardia species in terms of frequency. Considering cryptosporidiosis in the differential diagnosis of gastroenteritis in immunocompetent persons and including a search for Cryptosporidium oocysts in routine parasitological examinations of fecal samples appear warranted.

Adolescent↗