Biomedical subjects

Jonas Lundberg

Publications and source records attributed to Jonas Lundberg.

8 recordsLinked to original sources

PubMed2006

Avoidance of complications after the use of deep inferior epigastric perforator flaps for reconstruction of the breast.

We assessed 50 consecutive unilateral deep inferior epigastric perforator (DIEP) flaps for breast reconstruction to find out our morbidity and how to avoid it. We routinely dissected the superficial epigastric vein bilaterally and perforators ipsilaterally. If there were insufficient perforators on the ipsilateral side, we then dissected the contralateral side. We made an additional anastomosis to the superficial epigastric vein in cases of venous congestion after reperfusion that could threaten flap survival. One perforator was used on 31 occasions, and the contralateral side was dissected in 16. A prophylactic anastomosis of superficial epigastric vein was done in 3. No flap was lost completely but 5 partially necrosed. A comparison of the first 25 and the second 25 flaps showed more dissections of the contralateral side and more prophylactic anastomoses of the superficial epigastric vein in the second 25. Partial necrosis was less common in the second 25. We suggest that more liberal dissection of the contralateral side and the prophylactic anastomosis of the superficial epigastric vein to lower morbidity and give better cosmetic results.

Adult↗

PubMed2003

Preservation of rat skeletal muscle energy metabolism by illumination.

Skeletal muscle viability is crucially dependent on the tissue levels of its high energy phosphates. In this study we investigated the effect of the preservation medium Perfadex and illumination with Singlet Oxygen Energy (SOE). Singlet oxygen can be produced photochemically by energy transfer from an excited photosensitizer. The energy emitted from singlet oxygen upon relaxation to its triplet state is captured as photons at 634 nm and is here referred to as SOE. Rat hind limb rectus femoris muscles were preserved for five hours at 22 degrees C in Perfadex, saline, SOE illuminated Perfadex or SOE illuminated saline. Extracts of the muscles were analysed by 31P NMR. Data were analysed using two-way analysis of variance and are given as mean values micromol/g dry weight) +/- SEM. The ATP concentration was higher (p = 0.006) in saline groups (4.52) compared with Perfadex groups (2.82). There was no statistically significant difference in PCr between the saline groups (1.25) and Perfadex groups (0.82). However, there were higher (p = 0.003) ATP in the SOE illuminated groups (4.61) compared with the non-illuminated groups (2.73). The PCr was also higher (p < 0.0001) in the SOE illuminated groups (1.89) compared with the non-illuminated groups (0.18). In conclusion, Perfadex in this experimental model was incapable of preserving the high energy phosphates in skeletal muscle during 5 hours of ischemia. Illumination with SOE at 634 nm improved the preservation potential, in terms of a positive effect on the energy status of the muscle cell.

Adenosine Triphosphate↗

PubMed2002

Silencing of the PTEN tumor-suppressor gene in anaplastic thyroid cancer.

Germline mutations in the tumor-suppressor gene PTEN (MMAC1, TEP1) are found in Cowden syndrome, which predisposes to hamartomas, breast cancer, trichilemmomas, and thyroid tumors of follicular epithelium. PTEN has also been found to be somatically deleted, mutated, and/or silenced in various sporadically occurring cancers such as glioblastoma, breast cancer, kidney cancer, malignant melanoma, and endometrial cancer. Loss or reduction of PTEN protein expression as well as inappropriate subcellular compartmentalization is seen in non-medullary thyroid cancers. However, although allelic loss of the PTEN locus in 10q23.3 is frequently seen, this is not coupled with mutations in the PTEN gene. To approach further the frequency and mechanism behind PTEN silencing, we screened a panel of 87 sporadic thyroid tumors for PTEN mRNA expression, including 14 anaplastic carcinomas, 37 follicular carcinomas, 21 atypical adenomas, and 15 ordinary adenomas. Complete loss of PTEN mRNA expression was evident in six of the tumors, including four anaplastic carcinomas, one widely invasive carcinoma, and one ordinary adenoma. The transcriptional silencing of PTEN was significantly associated with the anaplastic subtype, suggesting that PTEN is involved in the carcinogenesis of highly malignant or late-stage thyroid cancers, whereas this particular mechanism appears to be of minor importance in differentiated follicular thyroid tumors. No association was observed between the expression, loss of heterozygosity, and mutation status in the 33 cases in which these parameters were compared. This indicates that PTEN silencing is a result of a wide variety of epigenetic and/or structural silencing mechanisms rather than a consequence of structural biallelic inactivation of the classical type. Furthermore, the high rate of alterations in the 10q23 region might indicate the presence of an as-yet unknown tumor-suppressor gene with an important role in the development of thyroid tumors.

Adenoma↗

PubMed2002

Improved energetic recovery of skeletal muscle in response to ischemia and reperfusion injury followed by in vivo 31P-magnetic resonance spectroscopy.

It is of great clinical interest to improve postischemic tissue recovery during microsurgical transfers. The effect of singlet oxygen energy (SOE) as photon illumination at 634 nm on rat skeletal muscle during ischemia and postischemic reperfusion was investigated noninvasively and continuously by in vivo (31)P-magnetic resonance spectroscopy ((31)P-MRS). A model of pedicled rat rectus femoris muscle was used, where phosphorous metabolites were followed before onset of ischemia (control), after 4 h of ischemia, and after 1 h of reperfusion. Two groups were studied: one control group (n = 10), and one SOE-treated group (n = 10). Blood perfusion was measured by laser Doppler flowmetry (LDF) during the study. After 4 h of ischemia, ATP levels were 72% and 51% of normal control values in the illuminated group and the control group, respectively (P < 0.05). After 1 h of postischemic reperfusion, phosphocreatine (PCr) recovered to 79% and adenosine triphosphate (ATP) to 71% in the illuminated group, whereas in the control group, the recovery was 57% and 51%, respectively (P < 0.05). It is concluded that singlet oxygen energy has a beneficial effect on the energy state of skeletal muscle during ischemia and postischemic reperfusion.

Adenosine Triphosphate↗

PubMed2002

Energy metabolism during microsurgical transfer of human skeletal muscle assessed by high-pressure liquid chromatography and by 31P-nuclear magnetic resonance.

The effect of ischaemia and reperfusion on human skeletal muscle was studied during free vascularised muscle transfer. Muscle biopsy specimens were taken from patients having microsurgical muscle transfer, 18 cases (17 patients; 12 men, 5 women). The biopsies were taken three times: before transfer of the muscle (control), at maximum ischaemic time, and one hour after revascularisation. The biopsy specimens were analysed for purine nucleotides, by high-pressure liquid chromatography (HPLC), and by nuclear magnetic resonance (NMR) at 500 MHz. Phosphocreatine (PCr) recovered only partially (79%) and adenosine triphosphate (ATP) did not differ significantly from normal control after revascularisation and a mean ischaemic time of 114 minutes. NMR measurements showed an accumulation of glucose-6-phosphate (G-6-P) during the ischaemic period, indicating anaerobic metabolism. After three hours of ischaemia and one hour of reperfusion the PCr recovery was less than 60% (r = 0.7). The results confirm those of previous animal studies, which set three hours normothermic ischaemia as a safe limit for tissue preservation when transferring skeletal muscle. Longer ischaemic times may cause serious postoperative healing problems and reduced muscle function.

Adenosine Triphosphate↗

PubMedDate not supplied

Do women simply complain more? National patient injury claims data show gender and age differences.

The Swedish Counties Mutual Insurance (LOF) owns and operates the Swedish Patient Insurance Company, (PSR) a no-blame insurance system that compensates patients for injuries that result from errors in medical practice. We combined malpractice claims data (from PSR) with national hospital discharge registry data (National Board of Health and Welfare-Socialstyrelsen) and determined Swedish inpatient malpractice claims rates for the years 1996-2000. Women have higher claims rates than men, but their claims are adjudicated as valid more often than men's claims. The data are consistent with other lines of evidence suggesting poorer quality of care for women, e.g., heart disease, kidney disease, and cancer. Middle-aged (40- to 59-year-old) patients file malpractice claims at almost twice the national rate, whereas patients younger than 19 years and older than 80 years of age file at significantly below the average rate. Differences in claims rates have major financial and quality of care implications. Further studies are needed.

Adolescent↗

PubMedDate not supplied

Do health care managers know the comparative quality of their care?

Compared with other industries, health care is a high-risk industry. In this study, two national data sets on patient claims and a survey of improvement efforts in Swedish health care were used to investigate the linkage between how health care managers perceive their performance regarding adverse medical events and their performance as reflected in patient malpractice claims rates. The departments' focus on patient safety issues in their improvement efforts was also evaluated. Our results show that Swedish health care department managers underestimate their departments' frequency of adverse medical events relative to that of similar units. Also, there is no correlation between the managers' perception of adverse medical events and their actual frequency of patient malpractice claims. More research is needed on the use of patient-generated malpractice claims and claims rates to promote a higher awareness of the magnitude of the safety problems in health care.

Attitude of Health Personnel↗

PubMedDate not supplied

The one-person randomized controlled trial.

Currently, the gold standard for collection of clinical evidence is the randomized controlled trial (RCT), preferably with large, multicenter samples of subjects. Although this approach provides valuable information, many clinicians find it difficult to translate RCT results to the individual patient level. In this report, a statistical approach called Design of Experiments (DOE) is described as a method of applying the principles of RCTs one person at a time. An overview of the method, with a simple clinical example, is presented. As shown, DOE is a more efficient method than the sequential approach often taken by clinicians and their patients when evaluating various treatment choices. Further, the effect of multiple interventions can be assessed, alone or in combination with each other. In this way, DOE can be an important addition to the field of evidence-based medicine, although further studies are needed.

Data Interpretation, Statistical↗