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Biomedical subjects

M Lindh

Publications and source records attributed to M Lindh.

At least 37 records · Page 2Linked to original sources
PubMed1999

Percutaneous placement of stents in chronic iliac and aortic occlusive disease.

OBJECTIVES: to evaluate the long-term results of stenting in iliac and aortic occlusive disease and identify factors predicting clinical outcome. DESIGN: retrospective study. MATERIALS AND METHODS: 82 patients (87 limbs) with stenoses (n =63) and occlusions (n =24) in the aortoiliac segment were treated with stents. 81 lesions involved the iliac arteries, 3 the infrarenal aorta and 3 the aortic bifurcation. Primary stenting was performed in 57 limbs (complex stenotic lesions and occlusions). Stents were placed following failed PTA in 30 limbs. Median follow-up was 13.2 months (1-66 months). RESULTS: technical success was 99% and clinical success 89%. Cumulative primary and secondary patency of stented iliac atherosclerotic lesions at 1 and 3 years was 75 and 61%, and 83 and 75% respectively. The factors predicting outcome of primary patency identified in Cox multivariate analysis were ankle-brachial index (ABI) prior stenting (p =0.03) and length of the lesion (p =0. 007). Major non-fatal complications occurred in 7.4% of the patients and there were no deaths attributed to the treatment. The 30-day mortality was 3.7%. CONCLUSION: stenting of complex aortoiliac stenoses and chronic occlusions is a safe and effective treatment modality. Long lesions and lower pre-procedure ABIs were found to negatively influence outcome.

Adult↗
PubMed1999

Chronic hepatitis C in Sweden: genotype distribution over time in different epidemiological settings.

Hepatitis C virus (HCV) strains are divided into 6 genotypes and several subtypes. Recent studies reported a change in the relative frequency of genotypes within certain regions. We studied the HCV genotype in 312 Swedish patients with chronic hepatitis C, using a core region primer-specific PCR, and grouped the patients according to parenteral risk factors. The date of infection could be estimated in 127 cases. Genotypes 1a (35%) and 3 (31%) were the most common genotypes, followed by genotype 2 (17%), while only 6% had genotype 1b. Genotype 3 was relatively more frequent among subjects infected sexually or by intravenous drug use. The genotype distribution was different from that in studies from other parts of the world, with a lower frequency of genotype 1 (especially 1b) and a higher frequency of genotype 3. The frequency of genotype 1b has decreased and genotype 3 increased over time. The reasons for a different distribution of genotypes in Sweden, compared with other countries, might be a relatively recent introduction of HCV into the population, or a different pattern of transmission.

Adult↗
PubMed1999

Chronic hepatitis B in children in Gothenburg, Sweden.

Sweden is a low prevalence area for hepatitis B, but the number of chronic carriers has increased during the last decade due to immigration. Out of a total of 120 children with identified chronic hepatitis B in Gothenburg, Sweden, 93 were investigated during the 2-year period 1994-95. The children had a mean age of 10.9 years and originated from 21 different countries. Most infections were discovered during various screening programmes after arrival in Sweden. A total of 90 of the 93 children were HBV-DNA positive by Amplicor HBV Monitor (Roche Diagnostics) and 58% (54/93) were HBeAg positive. All children either originated from areas with a high or medium prevalence of HBV infection (81/93, 87%) or were born in Sweden to mothers originating from high or medium prevalence countries (12/93, 13%). Three of these 12 children were vertically infected in spite of adequate immunoprophylaxis and 8 were born to mothers with undiscovered chronic HBV infection. In all, 34 children had mothers who were HBsAg positive. No overt case of transmission was notified in day-care centres or schools, or from a child to a non-immune parent. None of the children reported any symptoms of liver disease, but 38% (35/93) had elevated aminotransferases. Therefore, screening programmes are essential to identify chronic HBV infection in children in order to prevent transmission and to find individuals at risk of progressive liver damage who should be considered for treatment.

Acute Disease↗
PubMed1999

Core promoter mutations and genotypes in relation to viral replication and liver damage in East Asian hepatitis B virus carriers.

Virus load and liver damage, as measured by quantitative polymerase chain reaction and histology activity index, were related to genotype and core promoter mutations in 43 chronic hepatitis B virus (HBV) carriers of East Asian origin. T-1762 mutants were more frequent in genotype C strains and were associated with more inflammation (P=.0036) and fibrosis (P=.0088) of the liver but not with hepatitis B e antigen (HBeAg) status or virus load. Conversely, precore mutations were associated with less liver inflammation (P=. 08), which was linked to HBeAg negativity and lower viral replication. Carriers with genotype C were more often HBeAg positive (P=.03) with precore wild type strains and more-severe liver inflammation (P=.009) than were those with genotype B. These findings suggest that pathogenic differences between genotypes may exist and that the T-1762 mutation may be useful as a marker for progressive liver damage but seem to contradict that down-regulation of HBeAg production is the major effect of this mutation.

Adolescent↗
PubMed1999

HBeAg immunostaining of liver tissue in various stages of chronic hepatitis B.

AIMS: We studied the tissue expression of hepatitis B e antigen (HBeAg) in 29 liver biopsies from 27 HBV carriers. METHODS: HBeAg expression was assessed in relation to HBeAg in serum, precore mutations, HBV DNA levels and liver damage as measured by histology activity index. RESULTS: HBeAg in liver tissue was detected by immunostaining in 6 of 7 patients positive for HBeAg in serum. In patients negative for HBeAg in serum, HBeAg was detected in none of 11 specimens from patients infected exclusively with a precore mutant that disrupts HBeAg synthesis, as compared with 3 of 11 specimens from patients carrying HBV with an intact precore region. These 3 patients all showed high HBV DNA levels in serum and severe liver damage. CONCLUSIONS: Overall, viral replication was strongly associated with the cytoplasmic HBeAg and nuclear HBcAg staining, but not with tissue staining for HBsAg. Because of the close relationship between tissue HBeAg expression and high viral load, the pathogenetic importance of HBeAg remains unclear.

Adolescent↗
PubMed1999

Automated quantitative analysis of hepatitis B virus DNA by using the Cobas Amplicor HBV monitor test.

A highly sensitive method of quantitative analysis of hepatitis B virus (HBV) DNA in serum, the Cobas Amplicor HBV Monitor (Cobas-AM) test, was evaluated. Following a manual extraction of viral DNA, amplification, colorimetric detection, and quantitative determination are all automatically performed in the Cobas analyzer. Serially diluted samples with known HBV DNA concentrations were analyzed blindly. All samples with a virus concentration of 400 copies/ml and 83% of samples with a virus concentration of 100 copies/ml could be detected. A linear correlation between input HBV DNA and measured HBV DNA was seen in the range from 100 to 10(5) copies/ml. The mean coefficient of variation was 29.6% for all input levels and 18.9% for HBV DNA concentrations above 400 copies/ml. Samples with an HBV DNA level above 10(9) copies/ml could be reproducibly measured after predilution to 10(-4) or 10(-6) in negative serum; however, the level was underestimated if target DNA after dilution was still above the linear range of the assay. Quantitative results of the Cobas-AM test were interchangeable with measurements by the manual microwell plate version of Amplicor HBV Monitor (MWP-AM); the mean ratio for log Cobas-AM results/log MWP-AM results was 0.97 (standard error of the mean, 0.007) when serum samples from 153 chronic carriers were analyzed. The test should be of value for clinical assessment of chronic carriers and for monitoring the response to antiviral treatment. A limitation is the relatively narrow linear range of the assay, requiring predilution of high-titer (mainly hepatitis B e-antigen-positive) samples.

Adult↗
PubMed1999

Abdominal aortic aneurysm morphology in candidates for endovascular repair evaluated with spiral computed tomography and digital subtraction angiography.

PURPOSE: To analyze the morphology of abdominal aortic aneurysms (AAAs) and to study the usefulness of spiral computed tomography (CT) versus digital subtraction angiography (DSA) in the evaluation of patients for endovascular repair. METHODS: Of 133 AAA patients (120 men, mean age 67 years, range 52 to 84) evaluated preoperatively with CT imaging, 77 endograft candidates (68 men) were also assessed with intra-arterial DSA. Arterial parameters were measured on axial CT scans and angiographic films for comparison. RESULTS: Mean maximum AAA diameter was 58 +/- 11 mm (range 39 to 95). Aneurysmal neck diameter was consistently smaller on DSA than on CT (20.7 +/- 3.6 mm versus 23.0 +/ 3.5 mm, p < 0.0001). The distance from the most distal renal artery to the aortic bifurcation was longer on angiography than on CT (mean difference 10.0 mm, p < 0.0001). There was a positive correlation between the maximum AAA diameter and the AAA length (r = 0.49, p < 0.0001) and an inverse relationship between the neck length and the neck diameter (r = -0.36, p < 0.0001). No correlation was found between the maximum AAA diameter and maximum iliac diameter, angulation, or length. CONCLUSIONS: AAA anatomy varies widely and independently of the aneurysm size. Therefore, the maximum size of the aneurysm is a poor predictor of whether or not an aneurysm is suitable for endovascular repair. The discrepancy between angiographic and axial CT measurements suggests that neither alone is sufficient as a preoperative imaging technique when evaluating a patient for an endovascular graft procedure.

Aged↗
PubMed1998

[Chronic mesenteric ischemia. Endovascular treatment is as effective as open surgery].

Chronic mesenteric ischaemia is a rare but serious condition, which if untreated may cause death secondary to starvation or bowel infarction. As the symptoms are sometimes unspecific, its diagnosis may be delayed or missed. Although open surgical revascularisation has been the traditional treatment, a review of published reports suggests it to be associated with operative mortality rates of 6-9 per cent, and major morbidity rates of 22-26 per cent. Reports by others, and our own experience, suggest that endovascular treatment of mesenteric atherosclerotic obstructions with PTA (percutaneous transluminal angioplasty) and stenting may yield patency rates differing little from those associated with surgery, but significantly lower mortality (1.6%) and morbidity (5.6%).

Angioplasty, Balloon↗
PubMed1998

Mutation of nucleotide 1,762 in the core promoter region during hepatitis B e seroconversion and its relation to liver damage in hepatitis B e antigen carriers.

In chronic hepatitis B virus (HBV) infection, mutations develop frequently at nucleotides 1,762/1,764 in the X protein open reading frame, where the core promoter is also located. By using a modified allele-specific polymerase chain reaction method, the longitudinal emergence of the A-->T mutation at nucleotide 1,762 was studied in relation to precore mutations, genotype, and liver damage. First, samples from 38 carriers that were drawn before and after hepatitis B e (HBe) seroconversion were tested. T-1,762 mutant strains increased during HBe seroconversion (P = 0.004). In the HBe antigen-negative (HBeAg-) phase, T-1,762 mutants were found in 71% (12 of 17) of patients without compared with 33% (6 of 18) of patients with a concomitant precore mutation that prevents HBeAg synthesis (P = 0.08). Second, in 55 HBeAg+ patients, the T-1,762 mutant was found to be associated with more liver inflammation (P = 0.04) and fibrosis (P = 0.02), as measured by histology activity index (HAI) scores. The results show that the nucleotide (nt) 1,762 A-->T mutation often develops during HBe seroconversion, particularly in strains without precore mutations that prevent HBeAg production. For unknown reasons, the T-1,762 mutant was rare in genotype B strains. The presence of a T-1,762 mutant in the HBeAg+ phase may be useful for identifying immunoactivation in previously immunotolerant carriers, which could be valuable for selecting patients for interferon therapy.

Carrier State↗
PubMed1998

Genotyping of hepatitis B virus by restriction pattern analysis of a pre-S amplicon.

A method is described for genotyping of hepatitis B virus (HBV), based on the restriction fragment length polymorphism (RFLP) created by Ava2 and Dpn2 action on an amplified segment of the pre-S region. Analysing 51 database sequences by phylogenetic tree construction and RFLP prediction, the method was shown to be capable of detecting all known genotypes (A-F). The method was applied to 99 serum samples from hepatitis B e antigen (HBeAg)-positive chronic carriers, comparing observed agarose gel patterns with the RFLP predicted from the database sequences. In 95 typable samples the following genotypes were observed; 23 A, 20 B, 20 C, 22 D, 5 E and 5 F. Phylogenetic grouping of the 51 database sequences and RFLP genotyping of the 99 patient samples were compared with typing based on S gene analysis, showing disagreement in only one case, a database sequence of ayw subtype which was classified as genotype D by pre-S region and genotype A by S region analysis. This method should be useful for epidemiological investigations and for studying the potential influence of genotype on the course of infection.

Genotype↗
PubMed1998

Aggressive treatment of acute limb ischemia due to thrombosed popliteal aneurysms.

OBJECTIVE: The absence of infra-popliteal runoff in patients with acute limb ischemia and thrombosed popliteal aneurysms carries a high risk of amputation. A combined treatment method involving thrombolysis and surgery is reported. MATERIAL AND METHODS: Information regarding six patients was reviewed. Ankle brachial indices and degree of ischemia were recorded. All patients underwent digital subtraction angiography. In five patients thrombus dissolution was achieved using a combination of mechanical and pharmacologic therapy. One patient was judged incapable of withstanding any delay in reperfusion and was treated with isolated limb perfusion using a thrombolytic agent. All patients underwent surgical revascularization. Follow-up (1-3 years) consisted of duplex examinations at 6 months and yearly thereafter. RESULTS: Five patients had no measurable ankle brachial index (ABI), while one patient had an ABI of 0.4. Initial angiography noted all patients to have no runoff in continuity to the pedal arch. Following thrombolytic therapy, an adequate bypass vessel was noted in all cases, with reconstitution of the plantar arch in five patients. Distal revascularizations included one peroneal, and five below knee popliteal arterial bypasses. Fasciotomies were performed in four of the six patients. There were no amputations. One patient developed a persistent foot drop. Two patients developed bypass grafts occlusions; one of which required therapy. CONCLUSION: The pre-operative use of thrombolytic therapy is a safe and effective method to achieve limb salvage in this patient population. Patients must be capable of withstanding an additional period of ischemia allowing for reconstitution of distal runoff. Isolated limb perfusion is of use when a delay to reperfusion cannot be tolerated.

Acute Disease↗
PubMed1998

Persistent collateral perfusion of abdominal aortic aneurysm after endovascular repair does not lead to progressive change in aneurysm diameter.

PURPOSE: To differentiate between the phenomenon of collateral perfusion from a side branch versus graft-related endoleaks after endovascular repair of abdominal aortic aneurysms (AAA), with respect to aneurysm size and prognosis. METHODS: We successfully treated 64 AAA patients with endovascular grafting. We followed all the patients postoperatively with spiral computed tomography at one, three, six and 12 months, and biannually thereafter. We measured aneurysm diameters preoperatively and postoperatively. We calculated preoperatively the relation of maximum aortic diameter (D) to the thrombus-free lumen diameter (L) expressed as an L/D ratio. Median follow-up was 15 months. RESULTS: Sixteen patients had collateral perfusion during follow-up. We successfully treated two patients with embolization. One patient showed resolution of collateral perfusion after we stopped warfarin treatment. Two patients died of unrelated causes during follow-up. One patient was converted to surgical treatment, and two patients showed spontaneous resolution of their collateral perfusion. The group of patients with perfusion showed no statistically significant change of their aortic diameter on follow-up. The group of patients without perfusion showed a median decrease in aortic diameter of 8mm (p < 0.0001) at 18 months postoperatively. The group of patients with perfusion had significantly less thrombus in their aneurysm sac preoperatively than the group without perfusion, as expressed by the L/D ratio (mean L/D 0,61 versus 0,78, respectively; p=0.0021.) CONCLUSION: There was no significant increase in aortic diameter on an average 18 months postoperatively despite persistent collateral perfusion. This may indicate a halted disease progression in the short term. Embolization of collateral vessels is associated with risk of paraplegia. We recommend a conservative approach with close observation if aneurysm diameter is stable.

Adult↗
PubMed1998

Endovascular AAA exclusion: will stents with hooks and barbs prevent stent-graft migration?

PURPOSE: To investigate if stents with hooks and barbs will improve stent-graft fixation in the abdominal aorta. METHODS: Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cadaveric aortas. The grafts were anchored by stents as in endovascular abdominal aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks and barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-long, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Increasing longitudinal traction was applied to determine the displacement force needed to extract the stent-grafts. The radial force of the stents was measured and correlated to the displacement force. RESULTS: The median (interquartile range) displacement force needed to extract grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 to 10.8), and stent C 22.5 N (17.1 to 27.9), p < 0.001. Both hooks and barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall. The radial force of the stents had no impact on fixation, while aortic calcification and graft oversizing had marginal effects. CONCLUSIONS: Stent barbs and hooks increased the fixation of stent-grafts tenfold, while the radial force of stents had no impact. These data may prove important in future endograft development to prevent stent-graft migration after aneurysm exclusion.

Aged↗
PubMed1998

Dilatation of the infrarenal aneurysm neck after endovascular exclusion of abdominal aortic aneurysm.

PURPOSE: To determine the fate of the infrarenal aneurysm neck and suprarenal aorta after endovascular exclusion of abdominal aortic aneurysms (AAAs). METHODS: Thirty-four patients underwent endovascular AAA repair between January 1994 and December 1995 using custom-made stent-grafts constructed from polyester graft material and modified self-expanding Gianturco Z-stents sutured to the graft orifices. Thirty-one patients were available for follow-up. Pre- and postimplantation diameters were measured using spiral computed tomography in the infrarenal aneurysm neck and the suprarenal aorta at the level of the superior mesenteric artery (SMA). RESULTS: The mean follow-up time was 25 months. There was a significant increase of the diameter of the infrarenal aneurysm neck (+ 1.65 mm, p = 0.002), but not in the aorta at the level of the SMA (+0.52 mm, p = 0.100). There was no difference in the change in diameter in the infrarenal neck in the group with a stent adjacent to the level of measurement (n = 20) compared with the group without an adjacent stent (n = 11, p = 0.790). There was no correlation between preimplantation size of the infrarenal neck and its diameter change (r = 0.14, p = 0.488). There was no correlation (r = 0.10, p = 0.603) or association (chi-square test, p = 0.211) between aortic diameter change at the level of the SMA and the infrarenal neck. CONCLUSIONS: This investigation shows a significant dilatation of the infrarenal aneurysm neck, but not in the suprarenal aorta, after endovascular AAA repair with this device. The clinical significance of these findings is unclear. Whether such a dilatation in the infrarenal aneurysm neck may affect the long-term attachment of stent-grafts remains to be shown in the future.

Aged↗
PubMed1997

Cerebrospinal fluid apolipoprotein E (apoE) levels in Alzheimer's disease patients are increased at follow up and show a correlation with levels of tau protein.

Apolipoprotein E (apoE) levels were compared in cerebrospinal fluid (CSF) taken on two occasions, with an average 15 months follow up, from groups of patients with Alzheimer's disease (AD: n = 18), mild cognitive impairment (MCI; n = 9) and other dementia disorders (ODD; n = 9). In these groups, CSF apoE levels were between 2-3-fold higher than values for a group of 27 healthy age-matched controls. CSF apoE levels in the AD group were significantly increased at follow up, compared to levels obtained on the first sampling occasion. For the same cases it had been shown previously that CSF tau protein levels were increased at follow up [Blomberg, M., Jensen, M., Basun, H., Lannfelt, L. and Wahlund, L-O., Neurosci. Lett., 214 (1996) 163-166]. The AD, but not MCI, ODD or control groups, also showed statistically significant correlations between CSF apoE and tau protein levels at both the first (r = 0.585, P < 0.01) and follow up (r = 0.695, P > 0.001 ) samplings. It is concluded that CSF measures of both apoE and tau may reflect an intimate relationship between these two proteins in AD and could prove useful in monitoring the progression of this condition.

Adult↗
PubMed1997

The effect of endovascular aortic stents placed across the renal arteries.

OBJECTIVES: To investigate renal artery patency and renal function after deployment of aortic stents covering the orifices of renal arteries. DESIGN: Prospective open animal study. SETTING: Department of Experimental Surgery at a university hospital. MATERIALS: Twenty-three pigs were used. METHODS: Ten pigs were observed for 1 h after graft-anchoring aortic stents, Gianturco (5) and Palmaz (5), were placed so that the stents covered the renal arterial orifices. In 13 pigs, Gianturco (6) and Palmaz (7) stents without grafts were placed over the renal arteries and left in situ for 7 days. Renal function and blood flow were measured by renograms, iohexol clearance and ultrasonic blood flow meter and patency was verified by angiograms. The kidneys were microscopically examined for signs of ischaemia and microemboli. RESULTS: One renal artery covered by a graft-anchoring Gianturco stent occluded. The remaining renal arteries remained patent without any significant decrease in renal blood flow after stent deployment. Normal renal function and histology was maintained. CONCLUSIONS: Aortic stents placed at the level of the renal arteries do not affect renal blood flow within 1 week in this experimental model. This may prove valuable in endovascular treatment of aortic aneurysms and in other procedures involving stents.

Animals↗
PubMed1997

A telescopic stent-graft for aortoiliac implantation.

OBJECTIVES: To test a new delivery system for a telescopic stent-graft. MATERIALS: Variable overlap between the components of this stent-graft combination allows length adjustment. This device differs from other multi-component stent-grafts in that both components are contained within a single delivery system. METHODS: The stent-graft was implanted in the distal thoracic to suprarenal aorta of five pigs (35-50 kg), where the arterial diameter falls by almost 50%. The proximal and distal components of the stent-graft were targeted to bony landmarks in the vertebral column. RESULTS: Inspection of completion angiograms showed both proximal and distal stent-grafts to be within 1 mm of their target locations in all five experiments. Overall combined stent-graft length varied from 13.5 cm to 16.1 cm depending on the location of the bony landmark chosen as the distal target, and on the size of the pig. CONCLUSIONS: This system may be useful for the repair of abdominal aortic aneurysm whenever preoperative sizing is difficult due to aortic tortuosity, or precluded due to the urgency of the procedure.

Animals↗