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Biomedical subjects

G Nyberg

Publications and source records attributed to G Nyberg.

At least 37 records · Page 2Linked to original sources
PubMed2000

Dimensions of arteriovenous fistulas in patients with autosomal dominant polycystic kidney disease.

BACKGROUND/AIM: Aneurysms are known manifestations of autosomal dominant polycystic kidney disease (ADPKD). We investigated whether the dimensions of arteriovenous fistulas created for performance of haemodialysis were affected by the original disease. METHODS: The lumen diameter of the fistula was studied by ultrasound in 19 patients with ADPKD and in 19 control patients. The patients' sex, age, the duration of their fistulas, haemoglobin values and blood pressure levels were similar in both groups. The monitoring was performed along the forearm part of the vein, and the maximal diameter was measured. The diameters at the two needle insertion sites were also measured. RESULTS: The ADPKD patients had a significantly higher fistula diameter than the control patients: 12 (range 8-19) mm versus 8 (range 6-24) mm at the widest level (p = 0. 003). There were no significant differences in the diameters at the needle insertion sites. CONCLUSION: The receiving veins of arteriovenous fistulas in patients with ADPKD have an abnormality that causes a greater than normal dilatation in response to the arterialization. We postulate that this phenomenon is linked with the increased prevalence of aneurysms in ADPKD.

Adult↗
PubMed2000

The effect of isoniazid on BCG-induced toxicity in patients with superficial bladder cancer.

The use of bacillus Calmette-Guérin in the treatment of transitional cell cancer of the bladder has caused concern because of its associated adverse effects. We conducted a randomized prospective, double-blind, multicentre study to determine whether isoniazid prophylaxis could reduce BCG-induced toxicity without compromising its immunotherapeutic effects. Patients (n = 160) with histologically documented urothelial cancer (pTa-T1, pTis, G1-3) were treated with 6 weekly instillations of BCG Connaught strain, 81 mg, administered concomitantly with a 3-day course of isoniazid (300 mg o.d.) or placebo. Side-effects were recorded with each treatment and at follow-up. Of the patients treated with isoniazid, 19% remained free from side-effects, compared with 16% of the placebo group. Local side-effects confined to the bladder were significantly lower among those receiving isoniazid (35% vs. 48%, p < 0.01). Local side-effects together with systemic adverse effects such as fever, nausea or skin rash were experienced by 30% of patients in each arm. There were no differences in tumour recurrence between the two patient groups. Concomitant isoniazid reduces the local, but not the systemic side-effects of topically applied BCG without compromising the antitumour effect on superficial, transitional cell cancer of the bladder during a follow-up period that now exceeds 2 years.

Administration, Intravesical↗
PubMed1999

Increasing prevalence of cardiovascular disease in kidney transplant patients with Type 1 diabetes.

Type 1 diabetes was evaluated as a risk factor in kidney transplantation with respect to cardiovascular disease and with focus on changes over time. From 1985 to 1993, 159 Type 1 diabetic patients received first kidney transplants in Göteborg. Actual 5 year-survival of diabetic patients was 75% compared to 94% for matched controls, P < 0.0001, and survival of grafts was 60% compared to 75%. In the diabetic group, high age and preexisting coronary heart disease were additional, independent risk factors. When patients were divided into three groups according to time of transplantation, survival was found to improve initially but then declined, P = 0.03. Patients in the last group were older and 39% had pre existing vascular disease. The fact that Type 1 diabetic patients now reach end-stage renal failure at a higher age and with more established vascular disease calls for careful evaluation of a larger proportion of the transplant candidates.

Adolescent↗
PubMed1999

Stereotactic irradiation of skull base meningiomas with high energy protons.

Nineteen patients with inextirpable skull base meningioma with involvement of neurovascular structures were given irradiation with a 180 MeV proton beam at the The Svedberg Laboratory, Uppsala, Sweden. The patients were treated seated in a fixed position with a stereotactic approach. Titanium-markers to the outer table served for identification and verification of the target positioning for dose planning and irradiation. The patients were given a total dose of 24 Gy in four consecutive daily 6 Gy fractions. All patients have been followed for at least 36 months. So far no meningiomas have progressed after treatment. Two patients have developed corticosteroid responsive oedema in the target area 6 moths after treatment. Late, but not serious, symptoms of side effects have been observed in one patient.

Adult↗
PubMed1999

Clinical risk factors for recurrence of IgA nephropathy.

No clinical risk factors for recurrence of immunoglobulin A (IgA) nephropathy in kidney transplants have been defined. This is a single-centre retrospect analysis of recurrence in 104 first kidney transplant patients with biopsy-verified IgA nephropathy. Fifty patients had living donors. All but an identical twin were treated with cyclosporin A. The median follow-up time was 5 yr. Graft biopsies had been obtained from 35 grafts later than 6 months after transplantation, due to deteriorating graft function or gross proteinuria. Thirteen biopsies showed mesangial glomerulopathy proliferative in eleven cases with IgA deposits. Recurrence caused failure of six grafts. Eleven grafts with recurrence were from living donors (p = 0.005). No specific human leukocyte antigen (HLA) was identified as a risk factor. Known duration of original disease until end-stage renal failure was significantly shorter in patients with recurrence (median 5 yr, range 0-25 yr) compared with those without (median of 10 yr, range of 0-37 yr) (p = 0.015). Cumulative graft survival was not reduced in living versus cadaveric donor recipients.

Adolescent↗
PubMed1999

Neovascularization at the vascular pole region in diabetic glomerulopathy.

BACKGROUND: Diabetic nephropathy is associated with renal structural changes involving all of the compartments. Most characteristic is the diabetic glomerulopathy. Studies of the histological changes during the early phases of nephropathy have included the glomerulopathy and also the juxtaglomerular structures. Neovascularization, well-known in diabetic retinopathy, has also been observed in the kidney. The present study concerns estimates of frequency of neovascularization at the vascular pole region in early stages of diabetic nephropathy. METHODS: Extra efferent arterioles at the glomerular vascular pole were detected during measurements of the vascular pole area applying 1-microm serial sections through kidney biopsies. It was observed that more than one efferent arteriole existed occasionally. The present study was carried out with the aim of estimating the frequency of this phenomenon in diabetic patients and in non-diabetic controls, the diabetic patients categorized according to the level of albumin excretion rate. RESULTS: Neovascularization was first observed in IDDM patients with microalbuminuria. Some of the cases presented the phenomenon in all of the glomeruli studied. As the examinations of many kidney biopsies continued the phenomenon was observed also in the non-diabetic control group and in one IDDM patient with normoalbuminuria. However, the frequency was statistically highly significantly increased in patients with elevated albumin-excretion. Within this group a strong correlation between frequency of neovascularization and the severity of diabetic glomerulopathy is seen. CONCLUSIONS: The vascular abnormality localized to the vascular pole region is observed occasionally in the normal kidney, but the frequency is increased in patients with diabetic glomerulopathy. The abnormality may develop as a consequence of a long-standing diabetic glomerulopathy and might lead to less pronounced elevation of albumin excretion.

Adolescent↗
PubMed1999

A controlled study of the effects of isosorbide mononitrate on arterial blood pressure and pulse wave form in systolic hypertension.

OBJECTIVE: To determine the effect of an extended-release nitrate preparation on the arterial pulse wave and blood pressure of patients in whom systolic blood pressure was elevated in part by exaggerated pulse-wave reflectance. DESIGN: A double-blind randomized placebo-controlled crossover study was carried out. PATIENTS AND METHODS: The subjects were ten elderly patients with systolic hypertension resistant to conventional anti-hypertensive therapy. Pharmacodynamic responses to 2-week courses of placebo/isosorbide mononitrate (ISMN) were assessed in seven subjects by an ambulatory blood pressure monitor, and in all ten subjects by standard sphygmomanometry, arterial pulse-wave analysis and measurement of plasma nitrate concentration during peak and trough. RESULTS: Ambulatory systolic blood pressure was decreased by ISMN (P < 0.02) between 1000 and 2200 h. Ambulatory diastolic blood pressure fell with ISMN (P < 0.01) during the last 4 h of this period. At peak plasma nitrate levels, ISMN decreased the aortic systolic blood pressure (P < 0.01), ejection peak (P < 0.02) and augmentation component (P < 0.001) of the pulse wave; heart rate increased slightly (P < 0.03). CONCLUSION: ISMN has a role as an adjunct in the anti-hypertensive therapy of patients with refractory systolic hypertension due to exaggerated pulse-wave reflectance.

Aged↗
PubMed1999

Characterization of MK-801-induced behavior as a putative rat model of psychosis.

The objective of this study was to characterize the behavior induced by the N-methyl-D-aspartate receptor antagonist MK-801 (dizocilpine maleate) in rats as a model of psychosis. The temporal profile, dose dependence, age, and sex differences of the behavior are described. A gas chromatographic method for the analysis of MK-801 in plasma and brain was developed. Female rats showed 4 to 10 times more MK-801-induced behavior and displayed around 25 times higher serum and brain concentrations of MK-801 than male rats. Twenty-one neuroactive compounds, including a number of excitatory amino acid-active substances, were tested for the effect on MK-801-induced behavior. Neuroleptics blocked MK-801-induced behavior in a dose-dependent manner that correlated to their antipsychotic potency in humans. Adenosine receptor agonists and an N-methyl-D-aspartate receptor-associated glycine site antagonist showed putative antipsychotic effects. In conclusion, MK-801-induced behavior represents a rat excitatory amino acid hypofunction model of psychosis that appears to be of clinical relevance and may be of value in the search for new antipsychotic agents.

Aging↗
PubMed1998

Breast-feeding during treatment with cyclosporine.

BACKGROUND: Mothers treated with cyclosporine (CsA) have previously not been allowed to breast-feed due to the reported accumulation of the drug in breast milk. The purpose of this study was to evaluate the consequences of allowing breast-feeding. METHODS: Seven infants were breast-fed by mothers who had undergone kidney transplantation alone (n=5) or simultaneous kidney and pancreas transplants (n=2). In addition to CsA, all mothers received prednisolone at 5-7.5 mg/day and six mothers received azathioprine at 50-100 mg. CsA concentration was measured in the whole blood of mothers and babies and in breast milk. Serum creatinine was measured in babies 1 week after birth and after 4-12 months of breast-feeding. RESULTS: Blood CsA levels ranged from 55 to 130 ng/ml in mothers (12-hr trough), 50 to 227 ng/ml in breast milk (mean for each woman), and was below the detection limit of 30 ng/ml in all infants. Breast milk concentration ranged from 87 to 440 ng/ml in 16 samples obtained at various time points from one mother. Infants' serum creatinine ranged from 25 to 54 micromol/L at 1 week after birth and 23-52 micromol/L after breast-feeding. All babies thrived. CONCLUSIONS: Breast-fed infants of mothers treated with CsA received less than 300 microg per day of CsA and absorbed undetectable amounts. There were no demonstrable nephrotoxic effects or other side effects. Thus, women with kidney transplants could be allowed to breast-feed.

Adult↗
PubMed1998

Focal segmental glomerulosclerosis in a kidney transplant population: hereditary and sporadic forms.

Between 1985 and 1993, 16 of 1000 kidney transplant patients in Göteborg had biopsy-verified primary focal segmental glomerulosclerosis (FSGS), and among them they received 23 transplants. Their age range was 19-67 years (median 39 years). Patients were followed for 3-10 years (median 6.5 years). Eight patients were members of seven separate families in which at least one other member had FSGS, while eight cases were sporadic. The patients with hereditary FSGS were younger at onset of symptoms than sporadic cases (median 12.5 vs 26 years, P = 0.041) but not at the time of renal failure. Only one versus five had received immunotherapy. After transplantation, recurrence of FSGS occurred in five grafts, all in sporadic cases, and two of these were lost. In conclusion, it appears that there are at least two forms of FSGS, one hereditary and one sporadic form. The hereditary form does not seem to recur after transplantation, whereas the risk in sporadic cases is very high.

Adult↗
PubMed1998

Enlargement of the juxtaglomerular apparatus in insulin-dependent diabetes mellitus patients with microalbuminuria.

Kidney biopsies from 15 insulin-dependent diabetes mellitus (IDDM) patients with microalbuminuria were investigated to obtain quantitative data on the juxtaglomerular apparatus. The IDDM patients were young and normotensive with a mean duration of microalbuminuria of 2 years. Eight healthy kidney donors served as controls. Measurements taken by light microscopy, using 1-microm serial sections of epon blocks, included volumes of the juxtaglomerular apparatus and of glomeruli, areas of the macula densa and luminal area of the juxtaglomerular (afferent and efferent) arterioles at the level of the glomerular vascular pole. The volume of the juxtaglomerular apparatus was significantly larger in the IDDM group than in controls [6.08 (2.96-18.8) 10(4) microm3 vs 3.48 (1.84-5.21) 10(4) microm3, P=0.003, median and (range)], as was the volume of the juxtaglomerular apparatus relative to glomerular volume [1.89(1.28-4.21)% vs 1.48 (1.13-1.71)%, P=0.004]. The area of the macula densa was also larger in the IDDM patients (1370 microm2 vs 937 microm2, P=0.03). Luminal areas of the afferent and efferent arterioles and the ratio between them did not differ significantly between the two groups. In conclusion, the juxtaglomerular apparatus is enlarged more than would be expected from the glomerular hypertrophy in IDDM patients with microalbuminuria.

Adolescent↗
PubMed1998

Renal structural changes in insulin-dependent diabetic patients with albuminuria. Comparison of cases with onset of albuminuria after short or long duration.

The large interindividual variation in diabetes duration until the onset of nephropathy is partly unexplained. This study was performed to compare renal structure in insulin-dependent (IDDM) patients who had developed signs of nephropathy after a short or long duration of diabetes. Renal biopsies were obtained from 17 IDDM patients, with albumin excretion rate 20-300 microg/min and normal blood pressure. Six patients had <25 years duration ("short-term", early onset of microalbuminuria) and eight patients had duration >30 years ("long-term", late onset of microalbuminuria). Biopsies were obtained 18 months after entry into a study testing the effect of low-dose antihypertensives. Parameters characterizing diabetic glomerulopathy were significantly increased in IDDM patients compared with those in 17 living donors: Basement membrane thickness, mean and (CV): 591 nm (0.17) vs 320 nm (0.12), mesangial volume fraction per glomerulus 0.27 (0.19) vs 0.19 (0.10), matrix volume fraction per glomerulus 0.16 (0.20) vs 0.097 (0.22), matrix star volume 38.5 microm3 (0.43) vs 13.9 microm3 (0.31), (p<10(-4) for each). Comparison of short vs long-term patients showed no significant differences in glomerulopathy parameters, glomerular volume or extracellular material per glomerulus, whereas the fraction of occluded glomeruli was significantly increased in long-term patients. A close correlation obtained between fraction of occluded glomeruli and glomerular filtration rate (r=0.72, p= 0.001). Glomerular occlusion occurred unrelated to the severity of diabetic glomerulopathy. It is suggested that diabetic macroangiopathy and arteriolar hyalinization may play an important role in the renal function of patients with slow development of nephropathy.

Adult↗
PubMed1998

Morphologic high-risk factors in IgA nephropathy.

AIM: Morphologic risk factors for developing end-stage renal failure (ESRD) due to IgA nephropathy may be difficult to identify in populations where the course is benign in the vast majority. Ours is a high-risk population. METHODS: Protocols of 67 biopsies from native kidneys of kidney transplant patients with IgA nephropathy were reevaluated with respect to the prevalence of certain structural findings. Time points for onset of symptoms, biopsy procedure, and ESRD were recorded. RESULTS: Features seen with more than expected frequency were: extracapillary proliferation in 49%, cellular infiltrates in the interstitium in 89%, marked tubular atrophy in 54%, and IgA deposits in the peripheral capillary loops in 71%. With extracapillary proliferation the remaining time to ESRD was 3.5 +/- 3.2 versus 7.0 +/- 4.2 years without (p < 0.0004). With marked tubular atrophy the remaining time was 3.5 +/- 2.7 and 8.2 +/- 4.2 years without (p = 0.0002). Cellular infiltrates in the interstitium also signified shorter progression (p = 0.009). Except for the presence of IgA in the periphery, no finding by immune fluorescence was more frequent than expected or correlated with progression. CONCLUSION: Extracapillary proliferation, interstitial cellular infiltrates, marked tubular atrophy, and IgA deposits in the peripheral capillary loops indicate risk of progressive renal failure in IgA nephropathy, but other findings by immune fluorescence do not.

Adult↗
PubMed1998

Coronary aneurysms in patients with autosomal dominant polycystic kidney disease.

Patients with autosomal dominant polycystic kidney disease (ADPKD) have an increased risk of intracranial aneurysms. Reports on arterial aneurysms in other locations have not been conclusive. The present study was initiated to investigate the prevalence of coronary aneurysms. Thirty ADPKD patients who had undergone coronary angiography on clinical indication were identified, 15 after renal transplantation. For each ADPKD patient, a control patient was identified with end-stage renal disease, investigated by coronary angiography, and matched for age, sex, and time relation to transplantation. All angiograms were retrieved and reevaluated with respect to aneurysms, defined as an increase in artery diameter by 50% or more, as well as to pathologic ectasias not fulfilling this criterion. Aneurysms were detected in four ADPKD patients and two control subjects. Five more ADPKD patients, but none of the control subjects, had minor ectasias. One ADPKD patient had a dissecting aortic aneurysm, and another died of aortic dissection during bypass surgery. This study adds to the evidence of an increased risk of extracranial aneurysms in ADPKD patients.

Cardiovascular Diseases↗
PubMed1997

Systemic vasculitis in a kidney transplant population.

BACKGROUND: Systemic vasculitis as original disease might adversely influence the result of kidney transplantation. METHODS: The clinical course after 32 transplantations to 26 patients with microscopic polyangiitis, Wegener's granulomatosis, Henoch-Schonlein purpura, thrombotic thrombocytopenic purpura/hemolytic uremic syndrome, or Goodpasture's disease was evaluated. The median follow-up time was 82 months (range, 4-132 months). Frozen sera from 25 transplantations were analyzed for Goodpasture antibodies, myeloperoxidase antineutrophil cytoplasmic antibodies (ANCA), and proteinase 3 ANCA. RESULTS: Survival of patients and grafts did not differ between patients and matched controls. Recurrent vasculitis occurred with seven grafts (four patients with microscopic polyangiitis or Wegener's granulomatosis, two patients with Henoch-Schonlein purpura, and one patient thrombotic thrombocytopenic purpura). New-onset hematuria was the initial renal symptom in five patients. Treatment with corticosteroids, cyclophosphamide, and/or plasma exchange was most often effective, but two grafts were lost. Proteinase 3 ANCA titers were increased to 12-738 U/ml before seven transplants. The patient with the lowest titer lost his graft due to recurrence, two other patients had reversible recurrence after 1 year and 5 years, two patients lost their grafts due to unknown/unrelated causes, and two patients' grafts remain without recurrence. Myeloperoxidase ANCA were increased to 22-39 U/ml before two transplants, which have been uneventful for 4 years. CONCLUSIONS: An awareness of the small but perpetual risk of recurrence facilitates early treatment that may save the transplant. Testing for hematuria and early transplant biopsies, and possibly monitoring of ANCA titers, are essential, but pretransplant ANCA titers have no predictive value in asymptomatic patients. Results of kidney transplantation in patients with vasculitis are as good as in other patients.

Adult↗
PubMed1997

Bioequivalence, pharmacokinetic and pharmacodynamic response to combined extended release formulations of felodipine and metoprolol in healthy volunteers.

OBJECTIVE: The primary aim of this study was to investigate whether bioequivalence is achieved for a new fixed combination of extended-release (ER) felodipine and controlled-release (CR/ZOK) metoprolol compared with the free combination of felodipine ER metoprolol CR/ZOK. The second aim was to study whether there was an interaction in pharmacokinetics and pharmacodynamics between felodipine and metoprolol when administered as ER formulation. METHODS: Two four-way cross-over studies were performed in 36 young subjects and 24 elderly subjects with frequent measurement of drug plasma concentrations, blood pressures and heart rate. The pharmacokinetic analysis included enantioselective analysis in six subjects. RESULTS: Bioequivalence between the fixed combination and the free combination was observed for the two drugs (mean difference 27%) except for a minor deviation regarding Cmax of metoprolol in the elderly. No significant interaction was shown except for a small increase (6%) of metoprolol AUC in the younger subjects. Mean plasma S-/R-enantiomer ratios were almost identical for the different treatments. Blood pressure and heart rate was significantly reduced for the fixed combination compared with felodipine ER in the younger and the elderly subjects. No significant difference regarding pharmacodynamics was detected between the fixed combination and the corresponding free combination. CONCLUSION: The fixed combination consistently provides fairly constant and effective felodipine and metoprolol concentrations after once-daily administration of one tablet. It is clinically interchangeable with the free combination of metoprolol CR/ZOK tablets and felodipine ER tablets. Finally, felodipine and metoprolol do not interact on a pharmacokinetic level when administered as the fixed combination.

Adrenergic beta-Antagonists↗