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Biomedical subjects

J Pennings

Publications and source records attributed to J Pennings.

6 recordsLinked to original sources
PubMed2005

Gene expression pattern in spontaneously hypertensive rats exposed to urban particulate matter (EHC-93).

Epidemiological studies show associations of short-term exposure to particulate matter with morbidity and mortality. Although many studies investigate the health effects of ambient particulate matter, the associated mechanisms, and the causality, they often focus on classical parameters. The objective of the present study was to gain insight into the roles of a wide range of genes in this process. Particular attention has been paid to immediate oxidative stress in the lung. We isolated total lung RNA from spontaneously hypertensive male rats 2-40 h after exposure to reference EHC-93 (10 mg/kg). Our results show that exposure to particulate matter generates a time-dependent pattern of gene expression. From the 8799 genes or expressed sequence tags tested, we see that 132 genes were up- or downregulated shortly after exposure (i.e., 2-6 h), whereas after 15-21 h and 24-40 h, 46 and 56 genes showed altered expression, respectively. Focusing on the earliest point, 99 of the 132 genes were identified as unique. They include genes involved in an oxidative stress response (hemeoxygenase-1, metallothioneins, and thioredoxin reductase), an inflammatory response macrophage inflammatory protein-2, and tumor necrosis factor alpha), transcription factors belonging to the activating protein-1 family, and genes involved in cardiovascular functions. The present study, although not representing an ambient situation, is used to identify the biological pathways implicated in the initial injury response to PM exposure. Using Affymetrix chips, this study shows time-dependent gene expression, it identifies many genes that can be affected by exposure to particulate matter, and it confirms the involvement of oxidative stress in particulate-matter-related effects.

Air Pollutants↗
PubMed1995

Laparoscopic esophagomyotomy for achalasia.

Results of an ongoing clinical study treating achalasia patients with a transabdominal laparoscopic Heller myotomy and Toupet partial fundoplication are presented. Twelve patients underwent surgery between January 1992 and October 1993. All patients had barium esophagograms, preoperative endoscopy, esophageal manometry, 24-h pH studies, and extensive GI history preoperatively. Surgical complications included two perforations of the mucosa at the gastroesophageal junction repaired laparoscopically. There were no surgical mortalities and the average hospital stay was 39 h. Postoperatively all patients at follow-up had a repeat GI history, esophagogastroscopy, 24-h pH testing, and esophageal manometry. This follow-up showed good-to-excellent relief of dysphagia in all 12 patients with one patient complaining of heartburn documented to be from reflux postoperatively. Manometry showed a mean decrease in the lower esophageal sphincter pressure from 33.4 mmHg preoperatively to 19.3 mmHg postoperatively; 24-hour pH testing showed no significant reflux in the nine patients who had Heller myotomy plus a Toupet fundoplication. However, two of three patients who had Heller myotomy alone demonstrated abnormal 24-h pH testing. One of these patients was symptomatic and was found to have mild esophagitis by biopsy on postoperative endoscopy. These good results have persisted for mean follow-up of 16 months.

Adult↗
PubMed1995

Laparoscopic lumbar discectomy.

BACKGROUND: Minimally invasive spine surgery is gaining popularity. Results of currently used percutaneous posterior techniques fall short of standard open microdiscectomy. Using a posterior percutaneous technology with an anterior laparoscopic approach may improve results and still maintain the advantages of a minimally invasive procedure. METHODS: Patients with symptomatic lumbar protruded discs confirmed by computed tomography or magnetic resonance imaging were offered the procedure. Transperitoneal visualization of the retroperitoneum was supplemented with fluoroscopic guidance. A small window made to the disc allowed the percutaneous nucleotome to be inserted through the anterior annulus. The automated nucleotome aspirated the nucleus, leaving the ligaments intact. RESULTS: All patients underwent successful dissection and placement of the nucleotome. Of the 23 patients, 21 left the hospital in less than 24 hours. The initial neurologic outcome is that 20 out of 23 patients had improved symptoms or were asymptomatic. Complications were minimal. CONCLUSION: Laparoscopic lumbar discectomy is safe, and for carefully selected patients, can be an alternative to posterior microdiscectomy.

Adolescent↗
PubMed1994

Enteral versus parenteral nutrition after severe closed head injury.

We measured energy expenditure (MREE) and nitrogen excretion (UUN) in patients with severe head injury randomized to early parenteral (TPN, n = 21) or jejunal (ENT, n = 27) feeding with identical formulations. The MREE rose to 2400 +/- 531 kcal/day in both groups and remained at 135% +/- 26% to 146% +/- 42% of predicted energy expenditure over 4 weeks. Nitrogen excretion peaked the second week at 33.4 +/- 10 (TPN) and 31.2 +/- 7.5 (ENT) g N/day. Both routes were equally effective at meeting nutritional goals (1.2 x MREE, 2.5 g protein/kg/day intake, stabilized albumin and transferrin levels). Infections were equally frequent: 1.86 episodes/TPN patient versus 1.89 episodes/ENT patient. While patient charges were much greater for TPN, the hospital costs were similar for TPN and ENT support regimens. These findings show that patients with head injuries are hypermetabolic for weeks, that only 27% are capable of spontaneously eating nutritional requirements by discharge, and that either TPN or ENT support is equally effective when prescribed according to individual measurements of MREE and nitrogen excretion.

Adolescent↗