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Biomedical subjects

M Lindh

Publications and source records attributed to M Lindh.

At least 55 records · Page 3Linked to original sources

Renal arteries covered by aortic stents: clinical experience from endovascular grafting of aortic aneurysms.

OBJECTIVES: During the endovascular repair of abdominal aortic aneurysms (AAAs), effective anchoring of the stent-graft is difficult in the presence of a short infrarenal aneurysm neck. The aim of this study was to investigate renal artery patency and renal function after deployment of graft anchoring stents across the renal arteries. DESIGN: Retrospective open study. PATIENTS: Twenty-five renal arteries, in 18 patients treated by endovascular exclusion of an AAA, were intentionally covered with the Gianturco Z-stent to ensure stent graft attachment. METHODS: Renal artery patency was assessed by repeated spiral computed tomography (CT) scans and angiography. Creatinine levels, blood pressure and antihypertensive medication were recorded. Follow-up was a median 6 months (2-9). RESULTS: All 25 stent-covered renal arteries remained patent. CT showed a small infarct in one kidney. Creatinine was 108 mumol/l (89-133) before intervention and 98 mumol/l (87-127) at follow-up. Blood pressure was 150/80 mmHg on both occasions. Antihypertensive therapy was intensified in one patient whose creatinine level remained stable and whose separate renin sampling was normal. CONCLUSIONS: Covering the renal arteries with the Gianturco Z-stent does not seem to affect renal function within 6 months. Further follow-up is needed before suprarenal stent deployment can be advocated.

Aged↗

Genotypes, nt 1858 variants, and geographic origin of hepatitis B virus--large-scale analysis using a new genotyping method.

The nucleotide at position 1858 of hepatitis B virus has importance in chronic hepatitis B (HB) because a cytosine at nt 1858 effectively prevents virus escape through the precore TAG stop codon mutation. The relatedness between nt 1858 and genotypes was analyzed using a new genotyping method based on restriction fragment length polymorphism (RFLP) analysis of an S gene amplicon. Seventy-three gene bank sequences were analyzed by phylogenetic tree construction and RFLP prediction. A tree supporting the existence of 6 genotypes (A-F) was obtained, with C-1858 found in 9 of 9 A genotypes, 0 of 7 B, 0 of 19 C, 1 of 10 D, 0 of 2 E, and 3 of 3 F. Serum samples from 187 HB e antigen-positive chronic carriers were analyzed: Genotypes in northern Europeans were 60% A, 31% D; in southern Europeans and Middle Easterners 96% D; in Africans 53% A, 27% D, 20% E; and in East Asians 14% A, 43% B, 43% C. Cytosine at nt 1858 was found in 36 of 44 A, 0 of 32 B, 8 of 34 C, 0 of 59 D, 0 of 3 E, and 1 of 1 F genotype samples.

Africa↗

The importance of cofactors in the histologic progression of minimal and mild chronic hepatitis C.

A follow-up liver biopsy was done 9-16 years (mean 12 years) after initial biopsy in 20 untreated Swedish patients infected with hepatitis C (8 men, 12 women; mean age 30 years at initial biopsy) in whom first biopsy had been classified as chronic persistent hepatitis. A significant progression of liver damage was found when using Histology Activity Index (HAI) scoring according to Knodell (p=0.006 for total HAI score; p=0.03 for grading, i.e., sum of HAI components 1, 2, and 3; p=0.01 for staging, i.e., HAI component 4, fibrosis). Fourteen of 20 (70%) patients had increased while 6 had decreased or unchanged HAI scores on follow-up biopsy. Occasional heavy alcohol drinkers (n=6) had an increased follow-up HAI score as compared with nondrinkers (p<0.05). Eight of 14 who deteriorated on follow-up versus 0 of 6 with improved or unchanged liver histology were anti-HBc positive (p=0.04). There was no significant correlation between HCV genotype and prognosis; however, the only two patients with liver cirrhosis on follow-up had genotype 1b. In conclusion, most patients with minimal or mild chronic hepatitis C in the present study had histologic progression on the latest biopsy. Cofactors such as alcohol abuse and exposure to hepatitis B may have a greater influence than HCV alone in determining the rate of deterioration of liver disease.

Adolescent↗

Incidence of long-term sick-listing in an urban area of Sweden and its relationship with demographic data of the population.

By checking the card indexes of seven out of twelve Social Insurance Offices covering 66% of the total wage-earning population in the city of Göteborg the patients recorded for 90 days of continuous sick-listing were classified into four diagnostic categories according to the doctor's certificate: "non-specific pain" and "specific pain" of the musculoskeletal system, "other pain" and "non-pain" diagnoses. The overall yearly incidence of 90 days' sick-listing averaged 5.4%. A significant correlation was found between the incidence of 90 days' sick-listing due to "non-pain" and musculoskeletal pain diagnoses and the proportion of demographic characteristics of the areas. The hypothesis of presuming the highest association between non-specific pain diagnoses and demographic factors was rejected.

Child↗

Abdominal aortic aneurysms: experience with the Ivancev-Malmö endovascular system for aortomonoiliac stent-grafts.

PURPOSE: To describe a component-based aortomonoiliac stent-graft system and the first clinical results achieved with this device in endovascular abdominal aortic aneurysm (AAA) repair. METHODS: From November 1993 to October 1996, 45 patients aged 60 to 86 years underwent endoluminal exclusion of true AAAs (median diameter 60 mm) involving the common iliac arteries (median diameter 16 mm right and 15 mm left) using unilimb stent-grafts deployed with the Iancev-Malmö system. RESULTS: Six immediate conversions occurred in the beginning of the series due to endografts that were too short. Complications, including 2 inadvertent renal artery occlusions, 7 kinked grafts, 6 iliac artery dissections, and 3 perioccluder leaks, were prominent features in the first 15 patients. Five patients died in the postoperative period, four of whom were nonsurgical candidates. There were five significant stent-graft migrations: one 3 weeks after surgery due to mechanical injury of the proximal stent and four after 1 year owing to continuous dilation of a wide proximal neck, stent-graft placement in a conical, thrombus-lined proximal neck, and two instances of proximal extension separation from the main graft. Translumbar aneurysm perfusion required embolization in 3 patients. CONCLUSIONS: Despite early complications associated with a learning curve, exclusion of large AAAs using unilimb stent-grafts is feasible. Strict inclusion criteria are necessary in order to improve mortality among nonsurgical candidates and minimize the risk for late migration.

Aged↗

Changing aneurysmal morphology after endovascular grafting: relation to leakage or persistent perfusion.

PURPOSE: To relate changing abdominal aortic aneurysm (AAA) morphology after endovascular grafting to the presence of leakage, collateral perfusion, and other factors. METHODS: Thirty-five patients who underwent successful AAA endovascular grafting were evaluated. Self-expanding Z-stents and Dacron grafts were applied in bifurcated and aortomonoiliac systems. Postoperative diameter changes were calculated from repeated spiral computed tomographic scans, angiograms, and ultrasonic phase-locked echo-tracking scans during a median 6-month follow-up (interquartile range [IQR] 3 to 12). RESULTS: At 12 months, the diameters of completely excluded aneurysms had decreased 6 mm (IQR 2 to 11; p = 0.006). The proximal graft-anchoring stents had dilated 2 mm (IQR 0.5 to 3.3; p = 0.01). The aortic diameters immediately below the renal arteries but above the stents had not changed. Endoleakage and collateral perfusion (n = 13) were each associated with preserved aneurysm size and a 12 times higher risk of aneurysm dilation. After the leakage or the collateral perfusion had been treated, the aneurysm size decreased. Aneurysms with extensive intraluminal thrombi presented a reduced risk of leakage or perfusion. CONCLUSIONS: The diameters of endovascularly excluded AAAs decrease, except in cases of leakage or perfusion. Careful follow-up of patients with aortic endografts is necessary.

Aged↗

A randomized prospective study of vocational outcome in rehabilitation of patients with non-specific musculoskeletal pain: a multidisciplinary approach to patients identified after 90 days of sick-leave.

This study was designed to evaluate the effectiveness of a multidisciplinary rehabilitation programme offered to a general population with 90 days of sick-leave due to non-specific musculoskeletal pain. The results concerning return to work and re-sick-listing during a follow-up period of five years were evaluated for Swedes and immigrants separately. Compared to a control group, the rehabilitation offer resulted in improved work stability after work return among the Swedes. The immigrants, as a group, did not benefit from the programme compared to the controls in primary care.

Adolescent↗

Hepatitis B virus carriers without precore mutations in hepatitis B e antigen-negative stage show more severe liver damage.

Hepatitis B e antigen (HBeAg) is considered to be a major target for the immune response in chronic hepatitis B. The G-->A mutation at nucleotide 1896 may mediate viral escape by creating a TAG stop codon in the precore region, thus preventing HBeAg production. This mutation frequently evolves during HBe seroconversion if thymine, but rarely if cytosine, is present in position 1858. Applying a combination of polymerase chain reaction (PCR) and restriction enzyme action, we have studied the relation of the TAG mutation and the nucleotide (nt) 1858 variants to liver damage assessed by histology activity index (HAI) scoring in 175 chronic hepatitis B virus (HBV) carriers. A TAG mutation was found in 68 of 71 (96%) of HBeAg-negative carriers infected with a T-1858 strain, but not in any of 33 carriers infected exclusively with a C-1858 strain. Four patients showed a mutation of the precore start codon, and 2 had a TAA stop mutation at codon 2. HBeAg-positive infection with a mixture of wild-type and TAG mutant virus indicated active liver damage, because 8 of 9 (89%) of such patients had a Knodell HAI greater than or equal to 8. In HBeAg-negative stage, both inflammation and fibrosis were more pronounced in carriers infected with wild-type HBV compared with precore mutants. C-1858 strains were associated with more inflammation and fibrosis compared with T-1858 strains. C-1858 strains were found in 71% of northern European, 17% of southern European, 31% of African, 2% of Middle Eastern, and 10% of Far Eastern carriers. Analysis of these variants and mutants may prove useful for clinical evaluation and choice of therapy, and may be facilitated by the methods described.

Adolescent↗

Are self-expanding stents superior to balloon-expanded in dilating aortas? An experimental study in pigs.

OBJECTIVE: To study the stent/vessel interaction and distensibility following the natural increase in vascular diameter using self-expanding and balloon-expanded stents. DESIGN: Open experimental study. SETTING: Animal laboratory, university hospital. MATERIALS AND METHODS: Eight Palmaz (P) and eight Gianturco (G) stents were transluminally placed in the infrarenal aortas of 16 pigs. Pulsatile diameter changes above, at and below the stents were non-invasively monitored with an ultrasound phase-locked echo-tracking system before and immediately after stenting and at 4 and 18 weeks. Blood pressure was registered intra-arterially and stiffness (beta) was calculated. Intravascular ultrasound (IVUS) was performed at 18 weeks. RESULTS: Median weight increased from 20 kg (19-26) to 93 kg (62-130). Diameter of the aorta increased 60%. In group P no pulsatile diameter change could be measured at the stent (beta = infinity). In group G stenting increased stiffness from beta 20.7 (9.2) to 43.2 (8.0) (p < 0.05). After 18 weeks stiffness returned to beta 20.1 (12.4). Expanded, median diameter of the P stents was 7.4 (0.8) mm, not increasing after 18 weeks. Initial diameter of the G stents was 7.8 (1.0) mm, increasing 56% to 12.2 (2.3) mm (p < 0.05). IVUS revealed the G stents to be well attached to the vascular wall, but five P stents were detached within half of the circumference. CONCLUSION: Self-expanding stents follow the pulsatile diameter change of the vessel wall, not adversely affecting distensibility after 18 weeks. They show good attachment despite 56% dilation. In contrast, the balloon-expanded stents do not show pulsatile movement and may detach during vessel diameter increase. This may be of importance when choosing stents for endovascular treatment of abdominal aortic aneurysms.

Animals↗

Accuracy of duplex sonography before carotid endarterectomy--a comparison with angiography.

OBJECTIVES: The aim of this prospective study was to contribute to the evaluation of the reliability of Duplex sonography (DS) before carotid endarterectomy (CEA). DESIGN: The study was performed prospectively in a university hospital setting. METHODS: Eighty-one consecutive patients aged 49-83 years were examined with DS and carotid angiography (CAG) before CEA. The results of the DS were judged as either confident, or CAG was assessed to be necessary preoperatively. The results from the DS and the CAG were then compared. RESULTS: DS was judged as confident in 148 of the 162 arteries examined. In none of these 148 arteries did CAG change patient management in any way, and the agreement between DS and CAG was good. In the remaining 14 arteries CAG was judged necessary, in 11 arteries because DS assessed the internal carotid artery (ICA) as occluded, which was confirmed by CAG in 10 arteries. In three arteries the reason was poor quality of the DS, however these three arteries were correctly assessed as severely diseased. CONCLUSIONS: This study confirms that DS alone is sufficient in the preoperative evaluation before CEA, provided that CAG is performed whenever DS shows occlusion of the ICA, or when the quality of the DS is poor.

Aged↗

Endovascular stent-anchored aortic grafts: a comparison between self-expanding and balloon-expandable stents in minipigs.

PURPOSE: To study endovascular graft attachment with self-expanding Gianturco Z-stents and balloon-expanded Palmaz stents and the effect of these devices on the renal ostia. METHODS: Ten stent-grafts were constructed, 5 with Gianturco Z-stents and 5 with Palmaz stents. The endografts were implanted under fluoroscopic guidance into the abdominal aorta of 10 pigs so that the uncovered portion of the proximal stent extended over the renal artery orifices. Distal aortic blood pressure and flow were measured before and after graft placement and 1 hour postprocedure. The aorta was then exposed surgically, and the central portion of the stent-graft was inspected through an aortotomy to assess perigraft leakage. RESULTS: Stent-graft implantation was accurate and hemostatic in all cases, despite longitudinal folding of the graft due to oversizing. However, transverse folds produced pressure gradients (> 15 mmHg) between the ends of the graft in two cases. In another case, a pressure gradient resulted from partial thrombosis of the graft. In two cases, renal artery occlusion and thrombosis occurred due to coverage by the graft material. In two other animals, one of the renal arteries was entirely uncovered by a stent. The remaining 16 renal arteries were covered by the proximal stent but not the graft, as intended. One (6.25%) of these arteries thrombosed, but the remainder were grossly patent when the animals were sacrificed at 1 hour. CONCLUSIONS: Both Palmaz and Gianturco Z-stents produced hemostatic endovascular graft attachment, even in the presence of moderate graft oversizing. The risk of acute renal artery occlusion from juxtarenal stenting does not appear to be prohibitive, but longer term observations are needed.

Animals↗

Detection of hepatitis B virus precore TAG mutant by an amplification-created restriction site method.

A new method for detecting the hepatitis B virus (HBV) precore 1896 G-->A mutation is described. This mutation prevents hepatitis B e antigen production by introducing a TAG stop codon and has been associated with severe chronic and fulminant hepatitis. The method is based on a polymerase chain reaction (PCR) that creates a restriction enzyme (Bsu36I) cleavage site if the mutation is present. After incubation of the PCR product with Bsu36I and a subsequent agarose gel electrophoresis, the presence of the TAG mutant is revealed by an altered position of the DNA band. The method was compared with direct sequencing on 36 serum samples and correctly identified all samples containing mutant HBV. The TAG mutant was present in 17 cases (as mixed wild type and mutant virus in 4). Twelve of 18 patients with advanced liver disease confirmed by biopsy carried mutant HBV. This method of detecting HBV precore 1896 G-->A should be useful for evaluation and follow-up of patients and for prevalence studies.

Adolescent↗

Emergence of precore TAG mutation during hepatitis B e seroconversion and its dependence on pregenomic base pairing between nucleotides 1858 of 1896.

The G-->A mutation of nucleotide (nt) 1896 in the precore region of hepatitis B virus (HBV) prevents production of hepatitis B e antigen (HBeAg) by creating a TAG stop codon. This mutation is often found in anti-HBe-positive patients with productive HBV infection and has been associated with severe chronic and fulminant hepatitis in some geographic areas. Emergence of the TAG mutation during HBe seroconversion was studied as was its relationship with nt 1858, which forms a base pair with nt 1896 in the pregenomic RNA loop. A TAG mutant evolved in 18 (72%) of 25 patients with a T-1858 strain but in only 1 (8%) of 13 with a C-1858 strain. Viremia with C-1858 strains was, despite their limited ability to develop the TAG mutation, as persistent as with T-1858 strains. Generally, T-1858-infected patients in whom a TAG mutant did not emerge were HBV DNA-negative by polymerase chain reaction on follow-up, whereas patients who developed the TAG mutation had prolonged viremia.

Adolescent↗

Muscle fiber characteristics, capillaries and enzymes in patients with fibromyalgia and controls.

In 11 female patients with Fibromyalgia Syndrome (FS), biopsies from the m. vastus lateralis were analyzed, in order to reveal any possible changes which might explain muscular weakness and fatigue. Nineteen healthy subjects served as a control group. Light microscopy did not show any gross histopathological findings. Fiber composition and fiber areas did not differ between the two groups, except for a greater coefficient of variation of the area of type II A fibers and of the mean fiber area in the FS group. The number of capillaries per square millimeter and also the fiber area in relation to the capillaries, was lower in the FS patients. Analyses of enzymes showed decreased levels of 3-hydroxy-CoA-dehydrogenase and citrate synthase in the patient group. The reduced oxidative enzyme levels and capillarization indicate reduced physical activity, although this does not associate with muscle fiber hypotrophy.

Adult↗