Biomedical subjects

M Klukowski

Publications and source records attributed to M Klukowski.

At least 19 recordsLinked to original sources

PubMed2002

Large bowel perforation: morbidity and mortality.

Perforations of large bowel are rare but severe complications, mainly of colorectal cancer and colonic diverticulitis. The choice of the surgical procedure is still debated. We retrospectively studied peritonitis caused by large bowel perforation to assess predictors of mortality and safety of primary resection and anastomosis. We investigated 59 patients with large bowel perforation treated surgically as emergency cases: 18 patients underwent primary resection and anastomosis, 36 had primary resection of the diseased part of bowel without anastomosis, and 5 patients had non-resective procedures. The severity of peritonitis was assessed using Hinchey's classification and the Mannheim peritonitis index (MPI). Overall mortality was 16.9%. MPI score was significantly lower for survivors vs. non-survivors, and for patients with resection and anastomosis vs. those who underwent resection without anastomosis (p<0.001). The mortality rate was 11.1% for primary resection with anastomosis, and 22.2% for primary resection without anastomosis. No patient with MPI less than 25 died, while 10 (38.5%) of the patients with MPI of 26-36 died. In conclusion, a radical aggressive approach is recommended for most patients with large bowel perforation. Mortality and morbidity are closely related to the extent of intraperitoneal infection and the incidence of postoperative complications is higher in patients with perforation due to non-malignant causes.

Adult↗

PubMed2000

Testosterone, endurance, and Darwinian fitness: natural and sexual selection on the physiological bases of alternative male behaviors in side-blotched lizards.

The mechanistic bases of natural and sexual selection on physiological and behavioral traits were examined in male morphs of three colors of the side-blotched lizard, Uta stansburiana. Orange-throated males are aggressive and defend large territories with many females. Blue-throated males defend smaller territories with fewer females; however, blue-throated males assiduously mate guard females on their territory. Yellow-throated males do not defend a territory, but patrol a large home range. They obtain secretive copulations from females on the territories of dominant males. Males with bright orange throats had higher levels of plasma testosterone (T), endurance, activity, and home range size and concomitantly gained greater control over female home ranges than blue- or yellow-throated males. Experimentally elevating plasma T in yellow- and blue-throated males increased their endurance, activity, home range size, and control over female territories to levels that were seen in unmanipulated orange-throated males that had naturally high plasma T. However, the enhanced performance of orange-throated males is not without costs. Orange-throated males had low survival compared to the other morphs. Finally, some yellow-throated males transformed to a partial blue morphology late in the season and the endurance of these transforming yellow-throated males increased from early to late in the season. In addition, yellow-throated males that transformed to blue also had significantly higher plasma T late in the season compared to the plasma T earlier in the season. T appears to play an important role in the physiological changes that all three color morphs undergo during the process of maturation. In some yellow males, T plays an additional role in plastic changes in behavior and physiology late in the reproductive season. We discuss natural and sexual selection on physiological and behavioral traits that leads to the evolution of steroid regulation in the context of alternative male strategies.

Aggression↗

PubMed1998

The challenge hypothesis and seasonal changes in aggression and steroids in male northern fence lizards (Sceloporus undulatus hyacinthinus).

The challenge hypothesis has been very successful in explaining patterns of testosterone secretion in response to social stimuli in avian species. However, there have been few studies in nonavian vertebrates. We tested the challenge hypothesis in male northern fence lizards (Sceloporus undulatus hyacinthinus). These males are highly territorial and nonparental. Consequently, the challenge hypothesis predicts that plasma testosterone concentrations will be insensitive to aggressive interactions. Testosterone concentrations indeed were not significantly affected by either a short (3-15 min) simulated territorial intrusion ("challenge") in June or a longer (50-60 min) intrusion in July. Levels of corticosterone were elevated in challenged males in the long, but not the short, intrusion. Challenged males displayed significantly more intense territorial behaviors than did unchallenged control males. The intensity of territorial behavior changed significantly across the active season and was positively related to testosterone concentrations. Thus, while testosterone concentrations do not appear to be involved in rapid changes in aggressive behavior in the fence lizard, they probably are important in larger-scale behavioral changes throughout the season.

Aggression↗

PubMed1986