Biomedical subjects

C Strömberg

Publications and source records attributed to C Strömberg.

At least 19 recordsLinked to original sources

PubMed2003

Long-term results from laparoscopic common bile duct exploration.

BACKGROUND: The aim of this study was to evaluate the long-term results after laparoscopic common bile duct exploration (LCBDE). METHODS: A retrospective review of 175 consecutive patients who underwent attempted LCBDE between 1992 and 1999 was conducted. Laparoscopic transcystic exploration was accomplished in 110 patients and laparoscopic choledochotomy in 52 patients. Conversion to an open common bile duct exploration was required for 13 patients (7.4%). Retained common bile duct stones occurred in eight patients (4.6%). The 30-day postoperative morbidity was 6.9%, and there was no 30-day mortality. All the patients (alive and localized) received a questionnaire evaluating long-term results. RESULTS: Of the 175 patients, 169 (4 unrelated deaths and 2 patients lost to follow-up evaluation) received and 152 (90%) returned the questionnaire. The follow-up period ranged from 6 to 72 months (median, 36 months). One patient developed recurrent common bile duct stones. There were no signs or evidence of common bile duct stricture in any patient. CONCLUSION: The LCBDE procedure can be performed without increased risk of late bile duct complications.

Abscess↗

PubMed2001

Charnley cups retained during revision of the femoral component: repeated clinical and radiographic observations of 49 cups for 7-15 years.

This article concerns 49 consecutive polyethylene cups retained in cemented first revisions of the femoral component and evaluated on several occasions 7-15 years after the index operation. At the last follow-up 5 cups were revised, 3 were radiographically loose, 1 was revised because of recurrent dislocation and 1 stable cup was revised because the surgeon wished to use a 28 mm head. Moreover, 1 unrevised cup was radiographically loose. This corresponded to a mechanical failure rate of 0.1 (5/49) and revision rate of 0.1 (4/49). 3 cups which were radiographically loose (100% radiolucency) had not been revised when the stem was exchanged. If these cups were excluded, the revision rate would have dropped to 0.02 (1/46) and the mechanical failure rate to 0.04 (2/46). This indicates the importance of careful preoperative radiographic evaluation on both AP and lateral views. Progression of radiolucent lines always occurred as an increase in extension from the periphery to the central region of the interface. In conclusion, Charnley cups with non-circumferential radiolucent lines and little, if any, wear can be retained without compromising the longevity of the implant. However, it should be stressed that this conclusion is based on a patient population in which four-fifths of the patients at the index operation were 65 years of age or older.

Aged↗

PubMed2000

Cemented first-time revisions of the femoral component: prospective 7 to 13 years' follow-up using second-generation and third-generation technique.

In a prospective, consecutive study of first-time cemented femoral revisions, 109 hips were evaluated for a minimum of 7 years. There were 87 Charnley (18 standard, 69 long), 21 Spectron (3 standard, 18 long), and 1 Brunswick long-stem arthroplasties. There was an increased risk for rerevision in younger patients (P = .0001) and with use of standard stems (P = .002). Factors of importance for development of mechanical failure were younger age (P = .0001), presence of more pronounced bone defects (P < .005), use of standard stems (P < .0005), and presence of radiolucencies on the postoperative radiographs (Gruen zones 4 and 6) (P < .01). Our results confirm that cemented femoral revisions are a durable option in elderly patients, when improved cementing techniques and long-stem prostheses are used.

Adult↗

PubMed1997

[Laparoscopy possible even in cholelithiasis. Results for 96 patients from three different hospitals are reviewed].

At laparoscopic cholecystectomy, a procedure routinely used at Swedish surgery departments today, common bile duct stones are found to be present in 5-10 per cent of cases. During recent years, several alternative procedures have been evolved for the management of duct stones, such as operative or postoperative endoscopic sphincterolomy, or conversion to open surgery and choledochotomy. The article gives an account of laparoscopic treatment of common bile duct stones, and results obtained in 96 patients from three surgery departments in Sweden. Three different primary techniques were used: saline flushing via the cholangiography catheter, after intravenous injection of 1 mg of glucagon (in six cases of small stones); transcystic common duct exploration (TCDE), with cholodochoscopy and a Dermia basket (68 cases); and laparoscopic choledochotomy and choledochoscopy (22 cases). The success rate was 88 per cent (84/96), and mortality zero. In many cases the postoperative course was similar to that of patients undergoing laparoscopic cholecystectomy alone. We recommend TCDE in cases of common bile duct stones of no more than 8-9 mm in diameter, and where the cystic duct is large. Single-stage laparoscopic treatment of bile duct stones seems to be a safe and effective method of dealing with two problems in the same setting, and is an important alternative in the management of duct stones.

Adult↗

PubMed1996

The effects of midazolam and ephedrine on post-exercise autonomic chronotropic control of the heart in normal subjects.

Benzodiazepines may induce hypotension by inhibiting the pressor response. Ephedrine has adrenergic effects on the circulation. After exercise, changes in cardiovascular control impair orthostatic tolerance. The impaired pressure response can be compensated for by chronotropic control of the heart. We studied the effect of midazolam and ephedrine on post-exercise cardiac autonomic chronotropic control in six 21-year-old female volunteers, who received single doses of 15 mg midazolam, 50 mg ephedrine, or placebo orally according to a placebo-controlled, double-blind, crossover design. After exercise, the subjects assumed the supine position for rest, then a -10 degrees head-down position followed by a 70 degrees head-up position. Power spectral analysis of heart rate variability for 7 min and steady-state brachial arterial blood pressure were measured in each position. After administration of midazolam, three subjects had an abnormal fall in their arterial blood pressure (with one presyncope) as a response to head-up tilt. Changes in heart rate variability exceeded those seen during placebo treatment (p < 0.01) and involved oscillations, suggesting activation of both sympathetic and parasympathetic dynamics. After ephedrine administration, arterial blood pressure increased during head-down tilt, but parasympathetic dynamics to the heart were dampened. Head-up tilt induced increased sympathetic stimulation of the heart and a sympathicotonic cardiovascular response (p < 0.01). In conclusion, midazolam induced unexpectedly great changes in dynamic cardiac control during cardiovascular stimulation. Ephedrine increased tonic sympathetic activity and stabilized the neural circulatory control of the heart by immobilizing dynamic parasympathetic activation.

Adrenergic Agonists↗

PubMed1995

Angiotensin II receptor subtypes and phosphoinositide hydrolysis in rat adrenal medulla.

Angiotensin II (ANG) receptor subtypes were characterized by quantitative autoradiography after incubation with the ANG agonist [124I]Sar1-ANG in rat adrenal medulla. ANG receptors are highly localized in adrenal medulla. Specific binding was displaced by 4% and by 95% with the AT, receptor blocker losartan and the AT2 receptor competitor CGP 42112A, respectively. Analysis of competition curves indicated relative binding potencies for the AT2 population of CGP 42112A>PD 123319> PD 123177. ANG stimulated +-nositol phosphate formation in a dose-dependent manner in rat adrenal medulla. Losartan at concentrations of 10(-9) to 10(-5) M antagonized the effect of ANG, whereas PD 123177 or PD 123319 had no antagonistic action. However, at a higher concentration (10(-5) M) PD 123177 or PD 123319 potentiated the effect of ANG on InsP1-accumulation. In the presence of PD 123319 (10(-5) M) ANG dose-response curve was shifted to the left with no change in the maximal effect. This affect was blocked by the addition of losartan (10(-5) M). On the contrary, the addition of CGP 42112A (10(-6) M) inhibited ANG-induced increase in InsP1-accumulation. On the other hand, ANG and CGP 42112A reduced basal cyclic GMP formation, this effect was partially reverted by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor. Our results further demonstrate the presence of two ANG receptor subtypes in adrenal medulla: ANG binding to AT, receptor stimulates inositol phospholipid metabolism, whereas ANG binding to AT2 receptors decreases both inositol phosphate production and cGMP formation.

Adrenal Medulla↗

PubMed1995

Surgically assisted, rapid maxillary expansion in adults. A retrospective long-term follow-up study.

This study presents a technique for surgically assisted, rapid maxillary expansion performed on 20 patients and the results after orthodontic treatment. The mean age of the patients was 36.3 years and on average they had been followed-up for 3 years and 6 months. The results seemed to be reliable long-term. The definitive expansion in the first molar region was 7.1 mm +/- 2.4 and in the canine region 4.8 mm +/- 2.7. The relapse measured after the observation period, was in the corresponding regions 1.2 mm +/- 1.3 and 0.2 mm +/- 2.1. The study also seemed to support the theory that the suture, anterior to the incisive canal, never ossifies until very late in life.

Adolescent↗

PubMed1994

Angiotensin II AT1 receptor mediated contraction of the perfused rat cerebral artery.

The effect of angiotensin II on rat cerebral arteries was studied using isolated, perfused segments of anterior cerebral arteries. The infusion rate was set to maintain baseline intraluminal pressure at 75 mmHg. Angiotensin II (100 nM) increased the intraluminal pressure by 22.5 +/- 2.2 mmHg. Losartan, an AT1 antagonist, at 1 microM, completely blocked the effect of angiotensin II, whereas the AT2 ligands PD 123319 (1 microM) and CGP 42112 (1 microM) were ineffective. None of these AT1 or AT2 selective ligands alone displayed any agonist effects. The results show that angiotensin II induces contraction of the rat anterior cerebral artery by acting on AT1 receptors.

Angiotensin II↗

PubMed1994

Angiotensin II AT2 receptor stimulation increases cerebrovascular resistance during hemorrhagic hypotension in rats.

The effects of the angiotensin II (ANG II) AT2 ligand PD 123319 and the AT1 antagonist losartan on cerebral blood flow (CBF) were studied during hemorrhagic hypotension in anesthetized rats using laser-Doppler flowmetry. In the control group CBF remained stable when mean arterial blood pressure (MABP) was lowered from 84 mmHg (baseline) to 45 mmHg, whereafter there was a pressure dependent decrease in CBF indicating inadequacy of autoregulation. Cerebrovascular resistance (CVR) was reduced until MABP 40 mmHg, where a maximum dilation was reached. PD 123319 dose-dependently (3-30 mg/kg i.v.) increased CVR through all blood pressures. Losartan 3 mg/kg i.v. had an effect similar to PD 123319. Selective stimulation of AT2 receptors with intravenous ANG II infusion, in the presence of AT1 receptor blockade by losartan, also increased CVR. As a result, reduced CBF was seen in the treatment groups. The effects of ANG II and PD 123319 30 mg/kg were antagonized by the nonselective ANG II antagonist Sar1,Ile8-ANG II (4 micrograms/kg/min i.v.). None of the treatments affected baseline CBF. The results confirm that ANG II contributes to cerebrovascular resistance and participates in the regulation of CBF apparently through AT2 receptors.

Analysis of Variance↗

PubMed1994

Ethanol antagonism by atipamezole on motor performance in mice.

The interactions of an alpha 2-adrenoceptor antagonist, atipamezole, and an alpha 2-adrenoceptor agonist, dexmedetomidine, with ethanol were studied in male NIH Swiss mice. The mice were given (i.p.) atipamezole 0.1, 0.3, 1, 3 and 10 mg/kg and dexmedetomidine 0.01, 0.03, 0.1, 0.3, 1, 3 and 10 mg/kg; the ethanol doses were 1, 2 or 3 g/kg. Motor performance was measured by spontaneous locomotor activity and rotarod test. Dexmedetomidine impaired performance in both tests. The effect of dexmedetomidine peaked at the dose of 1 mg/kg. Three mg/kg of atipamezole abolished totally the effects of 0.3 mg/kg of dexmedetomidine and partially those of 1 mg/kg of dexmedetomidine. Atipamezole counteracted and dexmedetomidine enchanced ethanol effects in both tests. The interactions were not of pharmacokinetic origin since blood and brain ethanol and dexmedetomidine levels were unaltered at the time of testing. The results suggest that ethanol effects on motor performance in mice are mediated in part via central noradrenergic mechanisms, and blockade of alpha 2-adrenoceptors by atipamezole leads to considerable antagonism of these ethanol effects.

Adrenergic alpha-Agonists↗

PubMed1994

Long-term results of Charnley arthroplasty. A 12-16-year follow-up study.

A retrospective, long-term study was initiated to analyze clinical function, failures, and radiographic status in 95 Charnley low-friction arthroplasties performed during 1973-1977. Only patients with primary osteoarthrosis were included, and no patients were lost during the follow-up period. At the follow-up evaluation, 39 patients (41 hips) were deceased. Ten hips were revised (including 3 of the deceased patients), leaving 47 hips available for follow-up evaluation. Four patients (5 hips) were interviewed by telephone, and the remaining 42 hips were examined by the authors. With a mean follow-up period of 14 years, many of the patients had excellent pain relief with a mean Harris hip score for pain of 42 points (maximum, 44 points). Ninety-four percent of the patients were satisfied with their results. The survivorship for all 95 hips was 92% at 10 years and 83% at 16 years. Follow-up radiographs revealed that three (7%) of the femoral components were definitively loose, but only two (5%) of the acetabular components were probably loose. Forty-three percent of the hips had signs of polyethylene wear of the cup. The clinical and radiographic outcome is, in spite of an early cementing technique, very good in this long-term follow-up study.

Aged↗

PubMed1994

Angiotensin IV reverses the acute cerebral blood flow reduction after experimental subarachnoid hemorrhage in the rat.

The effect of angiotensin (ANG) IV on CBF after experimental subarachnoid hemorrhage (SAH) was studied in rats using laser-Doppler flowmetry. ANG IV (1 microgram/kg/min i.v.) or saline treatments were started 20 min after SAH. ANG IV increased CBF (from 45 to 84% of baseline) by 60 min. In the saline group, CBF remained low (51%). Pretreatment with the specific ANG II antagonist Sar1, Ile8-ANG II did not antagonize ANG IV. Determination of nitric oxide synthase (NOS) activity in vitro or inhibition of NOS in vivo did not support a role for NO in the action of ANG IV.

Amino Acid Oxidoreductases↗

PubMed1994

Angiotensin II AT2 receptor stimulation extends the upper limit of cerebral blood flow autoregulation: agonist effects of CGP 42112 and PD 123319.

The effects of the angiotensin II AT2 receptor ligands CGP 42112 and PD 123319, the AT1 antagonist losartan, and the nonselective angiotensin II antagonist Sar1,Ile8-angiotensin II on the upper limit of CBF autoregulation were studied in pentobarbital-anesthetized rats. Blood pressure was increased by intravenous phenylephrine infusion, while CBF was measured continuously from the parietal cortex by laser-Doppler flowmetry. Intravenous infusions of CGP 42112 (0.1 and 1 mg kg-1 min-1) and PD 123319 (0.36 and 1 mg kg-1 min-1) shifted the upper limit of CBF autoregulation toward higher blood pressures without affecting baseline CBF. Sar1,Ile8-angiotensin II (4 micrograms kg-1 min-1) had no effect on baseline CBF or CBF autoregulation but antagonized the effect of CGP 42112 and PD 123319. Losartan (10 mg/kg i.v. bolus) reduced baseline blood pressure and CBF and shifted the autoregulation curve toward higher blood pressures. Sar1,Ile8-angiotensin II blocked the effect of losartan on baseline CBF but not on CBF autoregulation. These results suggest that both CGP 42112 and PD 123319 exert their effects on CBF autoregulation through stimulation of angiotensin II AT2 receptors. The mechanism by which losartan affects CBF remains unclear.

1-Sarcosine-8-Isoleucine Angiotensin II↗

PubMed1994

Angiotensin AT2 receptor stimulation increases survival in gerbils with abrupt unilateral carotid ligation.

Previous studies showed that angiotensin II (AII) infusion increased survival in gerbils subjected to abrupt unilateral carotid ligation. Recently, stimulation of the AII AT2 receptor, reportedly effectively extended the blood pressure (BP) range of cerebral blood flow (CBF) autoregulation. We evaluated the survival of gerbils treated with PD-123319, a ligand of AT2 receptors, to test the hypothesis that restoration of BF to ischemic cerebral tissue produced by AII is mediated through AT2 receptors. Abrupt unilateral carotid ligation was performed on 300 gerbils. In five experimental groups, animals received no drug pretreatment: (a) saline; (b)-(d) PD-123319 1.0, 3.0, and 10 mg/kg; and (e) losartan 10 mg/kg. In three additional experimental groups, animals were pretreated with enalaprilat: (f) saline; (g) PD-123319, 10 mg/kg, and (h) losartan, 10 mg/kg. Survival for 48 h was significantly improved by PD-123319 (10 mg/kg) (p < 0.05) and by losartan (10 mg/kg) (p < 0.05) as compared with animals injected with saline. Pretreatment with enalaprilat neutralized the protective effect of losartan. PD-123319 is an AT2 agonist and improved survival in this animal model of stroke. Losartan, an AT1 antagonist, also improved survival, possibly through renin release and AT2 stimulation by endogenous AII. This effect was neutralized by enalaprilat.

Animals↗

PubMed1993

Effects of a sauna on the pharmacokinetics and pharmacodynamics of midazolam and ephedrine in healthy young women.

The effect of a sauna on the pharmacokinetics and pharmacodynamics of single doses of ephedrine 50 mg and midazolam 15 mg have been studied in 6 young healthy women in a placebo-controlled, double-blind study. The sauna (3 x 10 min; temperature 80-100 degrees C; relative humidity 30-50%) modified the pharmacokinetics of both drugs: it retarded the absorption of midazolam estimated as Ka values, and it reduced the mean plasma midazolam concentrations at 2 h; ephedrine, was absorbed more rapidly and the maximum plasma concentration occurred earlier than in the control sessions. Changes in the pharmacodynamics due to the sauna were consistent with the pharmacokinetic findings: midazolam decreased flicker recognition and induced exophoria significantly less during the early sauna period than in the control session, whereas ephedrine made the volunteers subjectively more alert at that time. Later, at 2.5 and 3.5 h (1 h 20 min and 2 h 20 min after cessation of the sauna), and despite the equalisation of the plasma levels, midazolam caused significantly more exophoria after the sauna than in the control situation. This indicates an influence of a sauna on drug pharmacodynamics in the post-sauna adaptive phase. The results suggest that exposure to a sauna may alter both drug pharmacokinetics and pharmacodynamics.

Absorption↗

PubMed1993

Nonpeptide angiotensin AT1 and AT2 receptor ligands modulate the upper limit of cerebral blood flow autoregulation in rats.

We investigated the effect of angiotensin AT1 and AT2 receptor blockade on the upper limit of CBF autoregulation in pentobarbital-anesthetized rats. CBF was measured by laser-Doppler flowmetry from the parietal cortex and MABP was increased by intravenous phenylephrine infusion. Neither the AT1 antagonist losartan nor the AT2 ligand PD 123319 nor angiotensin II (ANG II) in the presence of losartan affected baseline CBF. When the blood pressure was increased in the control group, CBF remained fairly constant up to 145 mm Hg and increased steeply after 150 mm Hg. Both PD 123319 (7-10 mg/kg) and losartan (1-10 mg/kg) shifted the upper limit of CBF autoregulation toward higher pressures. Intravenous infusion of PD 123319 was more effective than bolus injection. The losartan effect was dose dependent. Selective stimulation of AT2 receptors with an intravenous ANG II infusion (0.54 micrograms/min) in the presence of losartan did not reverse the effect of losartan on CBF autoregulation, but, on the contrary, appeared to further shift the upper limit of autoregulation toward higher pressures. The results implicate a role for both AT1 and AT2 angiotensin receptors in the regulation of CBF.

Angiotensin II↗

PubMed1992

Exercise alters the pharmacokinetics of midazolam.

Six healthy volunteers received 15 mg midazolam, 50 mg ephedrine, or placebo orally before a 50-minute aerobic treadmill exercise and in a control session. Plasma drug concentrations for pharmacokinetic calculations were estimated from samples drawn up to 24 hours after drug intake. Heart rate, blood pressure, critical flicker fusion test, Maddox wing test, and visual analog scales relating to mood and feelings of tiredness were included in the sessions as pharmacodynamic measures. These tests were made at 35, 55, and 75 minutes and at 2, 2 1/2, 3 1/2, and 5 hours after drug intake. Exercise impaired the absorption of midazolam and counteracted the midazolam-induced decrement in flicker fusion threshold. Whether the effect on flicker fusion was caused mainly by the pharmacokinetic changes or by a general alerting effect of exercise cannot be verified by this experiment. The kinetics of ephedrine was not affected by exercise, but exercise enhanced the tachycardic response to ephedrine and abolished its pressor effect.

Adult↗

PubMed1992

Biosynthetic human growth hormone preserves both muscle protein synthesis and the decrease in muscle-free glutamine, and improves whole-body nitrogen economy after operation.

As a reproducible human trauma model, patients (n = 17) undergoing elective cholecystectomy were studied for 3 postoperative days. They were randomly allocated to receive either recombinant human growth hormone (hGH; 0.3 U/kg/24 hours) or placebo together with total parenteral nutrition, including 0.2 gN/kg/24 hours and 135 kJ/kg/24 hours. Before operation and on the third postoperative day, percutaneous muscle biopsies were performed to determine the concentration and size distribution of ribosomes and the free amino acid concentrations. The significant postoperative decrease in the total ribosome concentration (15.3 +/- 6.4%) and the polyribosome concentration (20.9 +/- 6.5%) in the control group was impeded in the group receiving synthetic hGH. Muscle free glutamine decreased by 35.6 +/- 4.2% in the control group and to a lesser extent in the group that was given hGH after operation (p less than 0.05). The protein content of skeletal muscle was unchanged. The cumulated nitrogen balance for the study period was negative in the control group (-7.09 +/- 0.71 gN), but was not different from zero in the hGH group (-2.32 +/- 1.66 gN). It is concluded that synthetic hGH administered after operation has beneficial effects on the whole-body nitrogen economy, as indicated by the unchanged capacity for protein synthesis in skeletal muscle, the preserved levels of muscle free glutamine, and improvement in the whole-body nitrogen balance. The effects of hGH on skeletal muscle protein and amino acid metabolism can explain the postoperative nitrogen-sparing effect attributed to hGH.

Adult↗