Incidence of inferior vena cava thrombosis detected by transthoracic echocardiography in the immediate postoperative period after adult cardiac and general surgery

Venous thromboembolism is an important complication after general and cardiac surgery. Using transthoracic echocardiography, this study assessed the incidence of inferior vena cava (IVC) thrombosis among a total of 395 and 289 cardiac surgical and major surgical patients in the immediate postoperative period after cardiac and major surgery, respectively. All transthoracic echocardiography was performed by a specialist intensivist within 24 hours after surgery with special emphasis on using the subcostal view in the supine position to visualise the IVC. Of the 395 cardiac surgical patients studied, the IVC was successfully visualised using the subcostal view in 315 patients (79.8%) and eight of these patients (2.5%) had a partially obstructive thrombosis in the IVC. In 250 out of 289 (85%) general surgical patients, the IVC was also clearly visualised, but only one patient (0.4%) had an IVC thrombosis (2.5 vs 0.4%, P <0.05). In summary, visualisation of the IVC was feasible in most patients in the immediate postoperative period after both adult cardiac and major surgery. IVC thrombosis appeared to be more common after adult cardiac surgery than general surgery. A large prospective cohort study is needed to define the risk factors for IVC thrombus and whether early thromboprophylaxis can reduce the incidence of IVC thrombus after adult cardiac surgery.

Ultrasound-guided combined intermediate and deep cervical plexus nerve block for regional anaesthesia in oral and maxillofacial surgery

OBJECTIVES

We examined the application of an ultrasound-guided combined intermediate and deep cervical plexus nerve block for regional anaesthesia in patients undergoing oral and maxillofacial surgery.

METHODS

A total of 19 patients receiving ultrasound-guided combined intermediate and deep cervical plexus anaesthesia followed by neck surgery were examined prospectively. The sternocleidomastoid and the levator of the scapula muscles as well as the cervical transverse processes were used as easily depicted ultrasound landmarks for the injection of local anaesthetics. Under ultrasound guidance, a needle was advanced in the fascial band between the sternocleidomastoid and the levator of the scapula muscles and 15 ml of ropivacaine 0.75% was injected. Afterwards, the needle was advanced between the levator of the scapula and the hyperechoic contour of the cervical transverse processes and a further 15 ml of ropivacaine 0.75% was injected. The sensory block of the cervical nerve plexus, the analgesic efficacy of the block within 24 h after injection and potential block-related complications were assessed.

RESULTS

All patients showed a complete cervical plexus nerve block. No patient required analgesics within the first 24 h after anaesthesia. Two cases of blood aspiration were recorded. No further cervical plexus block-related complications were observed.

CONCLUSIONS

Ultrasound-guided combined intermediate and deep cervical plexus block is a feasible, effective and safe method for oral and maxillofacial surgical procedures.

Cardiovascular ultrasound in detecting central venous catheter thrombosis in the intensive care unit: splenectomy and antiphospholipid syndrome

Venous thrombosis of the upper extremities is becoming increasingly prevalent in the intensive care unit as a result of chronic in-dwelling central venous catheters. We report two rare cases in which combined transoesophageal echocardiography and vascular ultrasound examination aided in the identification of catheter-related thrombosis in two patients suffering from splenectomy-induced thrombocytosis and antiphospholipid syndrome respectively.

Ischemic preconditioning fails to confer additional protection against ischemia-reperfusion injury in the hypothyroid rat heart

There is accumulating evidence showing that ischemic preconditioning (PC) may lose its cardioprotective effect in the diseased states. The present study investigated whether PC can be effective in hypothyroidism, a clinical condition which is common and often accompanies cardiac diseases such as heart failure and myocardial infarction. Hypothyroidism was induced in rats by 3-week administration of 6n-propyl-2-thiouracil in water (0.05 %). Normal and hypothyroid hearts (HYPO) were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischemia and 45 min of reperfusion. A preconditioning protocol (PC) was also applied prior to ischemia. HYPO hearts had significantly improved post-ischemic recovery of left ventricular developed pressure, end-diastolic pressure and reduced lactate dehydrogenase release. Furthermore, phospho-JNK and p38 MAPK levels after ischemia and reperfusion were 4.0 and 3.0 fold lower in HYPO as compared to normal hearts (P<0.05). A different response to PC was observed in normal than in HYPO hearts. PC improved the post-ischemic recovery of function and reduced the extent of injury in normal hearts but had no additional effect on the hypothyroid hearts. This response, in the preconditioned normal hearts, resulted in 2.5 and 1.8 fold smaller expression of the phospho-JNK and phospho-p38 MAPK levels at the end of reperfusion, as compared to non-PC hearts (P<0.05), while in HYPO hearts, no additional reduction in the phosphorylation of these kinases was observed after PC. Hypothyroid hearts appear to be tolerant to ischemia-reperfusion injury. This response may be, at least in part, due to the down-regulation of ischemia-reperfusion induced activation of JNKs and p38 MAPK kinases. PC is not associated with further reduction in the activation of these kinases in the hypothyroid hearts and fails to confer added protection in those hearts.

Decreased vascular reactivity to alpha1 adrenergic stimulation in the presence of hypothyroid state: a part of an adaptive response?

AIM

A hypothyroid state frequently accompanies cardiac illnesses but its physiological significance for the cardiovascular hemodynamics remains largely unknown. Therefore, the present study investigated possible physiological consequences on vascular function in an experimental model of low thyroid hormone state.

METHODS

Hypothyroidism was induced in rats by the administration of 6-n-propyl-2-thiouracil in drinking water (final concentration of 0.05%) for 3 weeks, HYPO rats, and untreated rats served as controls (Control). Isolated aortic rings with or without endothelium (E+, E-) were contracted with KCl (10 to 60 mM) and phenylephrine (PE) (10(-10) to 10(-5) M). Maximal tension (Tmax) in g and EC(50) in response to PE and KCl were measured.

RESULTS

Tmax was significantly lower while EC(50) was significantly higher in response to PE in HYPO(E+) than in Control(E+). Upon endothelium removal, Tmax was not significantly different between the groups but EC(50) was still significantly higher in HYPO(E-) than in Control(E-). EC(50) in response to KCl was significantly higher in HYPO with or without endothelium and no difference was found in Tmax.

CONCLUSIONS

Hypothyroid aortic rings respond less to a1 adrenergic stimulation probably due to the endothelium modulatory effect as well as to intrinsic smooth muscle defect. This seems to be of important clinical relevance.

The influence of premedication and smoking

The history of smoking and premedication did not influence the proportion of patients who had a cough response to fentanyl when administrated as first agent during induction in anesthesia.

Hyperthyroid hearts display a phenotype of cardioprotection against ischemic stress: a possible involvement of heat shock protein 70

Hyperthyroid hearts are shown to display a phenotype of cardioprotection against ischemic stress, but the underlying signaling mechanisms remain largely unknown. The present study investigated the possible relation of HSP70 to the thyroid hormone induced cardioprotection. HSP70 is a redox-regulated molecular chaperone, and enhances cell survival under stress. Thyroxin (25 microg/100 g body weight) was administered to Wistar male rats for four days (THYR-4d) and two weeks (THYR-14d), respectively, while untreated animals served as controls (CON-4d, CON-14d). Isolated hearts from control and thyroxin treated rats were subjected to 20 min zero-flow ischemia followed by 45 min of reperfusion (I/R). The amount of HSP70 in the myocardium for THYR-14d was 1.85 times the levels of CON-14d (p < 0.05). The levels of HSP70 expression were no different between THYR-4d and CON-4d, p > 0.05. This was only accompanied by an increase in MDA levels (used as an index of oxidative stress) in THYR-14d compared to untreated hearts. These changes corresponded to a differential response of the heart to I/R; post-ischemic recovery of function was significantly increased in THYR-14d compared to CON-14d, and was no different between the THYR-4d and CON-4d hearts. In conclusion, long-term thyroxin administration results in increased tolerance of the myocardium to I/R and enhances the expression of HSP70 which may, at least in part, account for this response.

Thyroid hormone receptors alpha1 and beta1 are downregulated in the post-infarcted rat heart: consequences on the response to ischaemia-reperfusion

There is accumulating evidence that thyroid hormone metabolism is altered after myocardial infarction (AMI) but its physiological relevance remains largely unknown. The present study investigated the possible role of thyroid hormone signaling in the response of the post-infarcted heart to ischaemia-reperfusion. Wistar rats were subjected to left coronary artery ligation (AMI), or sham operation (SHAM). After 8 weeks, hearts from AMI and SHAM rats were perfused in Langendorff mode and subjected to 20 min of zero-flow global ischaemia (I) and 45 min of reperfusion (R); AMI(I/R), n = 7 and SHAM(I/R), n = 7. Basal left ventricular pressure (LVDP), +dp/dt, and -dp/dt were significantly reduced. Left ventricular weight of the viable myocardium was increased by 14% in the AMI as compared to SHAM hearts, P < 0.05. T(3) and T(4) plasma levels in nM were 1.83 (0.08) and 53.3 (2.9) for SHAM and 1.76 (0.06) and 59.4 (5.2) for AMI rats, respectively, P > 0.05. TRalpha1 and TRbeta1 expression levels were 1.3- and 1.8-fold less in AMI than in SHAM hearts, P < 0.05. Furthermore, SERCA and NHE1 expression levels were 2.1- and 1.8-fold less in AMI than in SHAM, P < 0.05. PKCepsilon was 1.35-fold more in AMI compared to SHAM, P < 0.05. Myocardial glycogen content (in micromol/g) was 7.8 (1.2) in AMI as compared to 4.4 (0.5) for SHAM hearts, P < 0.05. After I/R, left ventricular end-diastolic pressure at 45 min of R (LVEDP45 in mmHg) was 20.3 (3.2) for AMI(I/R) vs 50.6 (4.8) mmHg for SHAM(I/R), P < 0.05. LDH release per gram of tissue was 251 (103) for AMI(I/R) and 762 (74) for SHAM(I/R), P < 0.05. In conclusion, TRalpha1 and TRbeta1 are downregulated after myocardial infarction and this was associated with altered expression of thyroid hormone responsive genes and increased tolerance of the post-infarcted heart to ischaemia-reperfusion injury.

Ketamine-induced changes in metabolic and endocrine parameters of normal and 2-kidney 1-clip rats

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the effect of ketamine on the endocrine and lipid metabolic status of the renal-banded animals.

METHODS

Forty male rats were randomly divided into four groups. Group A served as control, Group B animals received ketamine intraperitoneally at a dose of 100 mg kg(-1), Group C was submitted to 2-kidney 1-clip experimental hypertension and Group D received ketamine as above, as well as being submitted to renal artery clipping. Atrial natriuretic peptide, angiotensin II and free fatty acid concentrations were measured in serum. In addition, adipose tissue lipoprotein lipase activity and angiotensin II content were determined, while the left ventricular weight relative to body weight was used as a cardiac hypertrophy index.

RESULTS

In renal-banded rats (Groups C and D) serum atrial natriuretic peptide, free fatty acid and angiotensin II concentrations as well as ventricular weight were increased, while adipose tissue lipoprotein lipase activity was lower than in control animals (Groups A and B). Ketamine administration did not influence angiotensin II concentrations either in normal (Group B) or banded rats (Group D). Ketamine increased serum atrial natriuretic peptide and free fatty acid concentrations only in normal animals (Group B). It had no influence on adipose tissue lipoprotein lipase activity either in normal (Group B) or banded animals (Group D). Adipose angiotensin II content did not differ between the four groups.

CONCLUSION

Ketamine increased the atrial natriuretic peptide and free fatty acid concentration in normal rats. In 2-kidney 1-clip animals, ketamine did not elicit an additional response of serum atrial natriuretic peptide or free fatty acids levels. Its contribution to these factors was not significant.

Mechanisms of ketamine action on lipid metabolism in rats

BACKGROUND AND OBJECTIVE

This study was conducted to determine the effect of ketamine on metabolic homoeostasis and particularly in lipoprotein lipase (LPL) activity in adipose tissue.

METHODS

Sixty male Wistar rats were divided into six groups of 10 each. Group A served as controls, while Groups B-F received, respectively, ketamine 60, 80, 100, 120 and 140 mg kg(-1) intraperitoneally. The animals were sacrificed 20 min after the administration of ketamine. Insulin concentrations in plasma and total cholesterol, triglyceride, high-density lipoprotein (HDL) and free fatty acid (FFA) concentrations in serum were measured. LPL activity in adipose tissue and medium-chain acyl-CoA dehydrogenase (MCAD) content in muscle were determined.

RESULTS

FFA concentrations in serum significantly increased from the second lowest dose of ketamine. Insulin concentrations in plasma did not exhibit any significant difference between groups. MCAD levels were 0.5-fold more in Group F than in Group A, while there were no significant differences between control group and Groups B-E. Furthermore, high concentrations (120 and 140 mg kg(-1)) of ketamine interfered with in metabolic homoeostasis by significantly reducing LPL activity, thus elevating triglyceride concentrations in serum without affecting cholesterol and HDL metabolism.

CONCLUSIONS

Ketamine induces various metabolic effects due to changes in adipose LPL activity and MCAD levels in muscles. These findings seem to be significant only at high doses.

Lipid kinetics in obese patients undergoing laparoscopy. the impact of cortisol inhibition by etomidate

The aim of this study was to investigate the response of cortisol, insulin and lipid parameters [serum Lipoprotein Lipase activity, choleseryl-ester transfer protein, triglycerides, total Cholesterol, High Density Lipoprotein, Free Fatty Acids] during the perioperative period in obese patients undergoing laparoscopic cholecystectomy. Twenty obese patients were included and divided in two groups. In group A (n=10) patients were anaesthetized with propofol and group B (n=10) with etomidate. Blood samples were collected before induction in anaesthesia, just after the end of the operation and at one, two and three hours postoperatively. According to our results, in both groups serum LPL activity showed a significant decrease whereas serum Free Fatty Acids a potent increase over time. Likewise, both groups did not demonstrate significant changes over time in choleseryl-ester transfer protein activity, total cholesterol, triglycerides, High Density Lipoprotein or insulin concentrations in serum. Furthermore, cortisol release was significantly inhibited in the etomidate group while substantially enhanced in propofol group. Additionally, apart of triglycerides, no difference was found between the two groups in all the lipid parameters and insulin concentrations. In conclusion, serum Free Fatty Acids levels and Lipoprotein Lipase activity demonstrated significant alterations in obese patients underwent laparoscopic cholecystectomy and this result did not seem to be related with the anaesthetic agent used for induction in anaesthesia.

Modifications of clonidine binding to rabbit liver protein under the influence of non-steroid-anti-inflammatory drugsin vitro

This study was designed to investigate the binding of clonidine to liver protein as well as the possible interactions with non-steroid anti-inflammatory drugs (NSAIDs) during the binding process in the rabbit. The binding of clonidine to slices (S) and homogenized slices (H) was estimated by a radioisotopic method following incubation with a mixture of cold and 3H-labelled clonidine in Ringer solution at 37 degrees C for 360 min. The binding of clonidine was assessed in the absence and presence of the following NSAIDs: flurbiprofen, ketoprofen, ibuprofen and acetylsalicylic acid. The results showed that the percentage of clonidine binding did not differ between intact and homogenized slices. The addition of all NSAIDs but ibuprofen, significantly decreased the protein binding of clonidine both in intact and homogenized liver slices. This finding could be attributed to the different affinity of ibuprofen for liver protein compared to the remaining NSAID's which may arise from a number of chemical properties including its dual Pka values.

Quinolone levels in serum and maxillofacial tissues under ibuprofen co-administration following surgical trauma

Administration of antibiotics is considered to be an important factor, during or after operational procedures in the maxillofacial area, in order to avoid post-surgical complications. Furthermore, administration of anti-inflammatory drugs is often prescribed for control of the post-operative pain. The aim of this study was to determine the levels of quinolones in serum and tissues (parotid gland, tongue, mandible), during traumatic injury in the oral cavity, with or without co-administration of ibuprofen, a non-steroidal anti-inflammatory drug. Four groups of Wistar rats, (A, B control), (C, D experimental) were used. In the experimental group, traumatic injury was performed through the whole length of the cheek. Groups B and D received ibuprofen. The quinolone levels in serum and tissues were estimated by the inhibition zone of B. subtilis. Free fatty acid (FFA) levels and the adrenal weight, considered as a stress index, were increased in trauma groups. Quinolone concentrations in serum and in most of the tissues were significantly higher in the experimental groups compared to the controls. However, the co-administration of ibuprofen caused a higher increase of the quinolone levels in the control animals than in the experimental groups.

Effect of losartan on insulin plasma concentrations and LPL activity in adipose tissue of hypertensive rats

The aim of this study is to determine the effect of losartan on insulin and angiotensin II (Ang II) concentrations in plasma as well as on lipoprotein lipase activity (LPL) and angiotensin II content in the adipose tissue of hypertensive rats. Fifty male rats were divided in five groups. Group A served as controls. Group B underwent renal artery stenosis. Group C were administered losartan (10 mg/kg/day) per os, while rats in group D were submitted to renal artery stenosis and were treated with losartan as above. Group E was used as sham-operated control. The animals were sacrificed at day 21. Blood samples were collected, and perirenal adipose tissue was isolated. Furthermore, adrenal's were removed and their relative weight (adrenal weight/body weight) was used as an index of sympathetic stimulation. According to our results, renovascular hypertension resulted in lower insulin concentrations and higher Ang II content in plasma. In hypertensive rats, LPL activity was decreased, while the adrenals' relative weight was elevated. On the other hand, losartan administration resulted in normalization of insulin concentrations in plasma and adrenals' relative weight, with consequent up regulation of LPL activity in adipose tissue. In conclusion, renovascular hypertension interferes in lipid metabolism by reducing LPL activity in adipose tissue, while losartan administration reverses this effect by enhancing insulin release and reducing sympathetic nervous system (SNS) stimulation.

Morphological changes of parotid glands following adjuvant arthritis and ibuprofen treatment in rats

Drug administration and numerous systemic diseases may cause morphological changes of the parotid gland. The aim of this study was to investigate the possible relationship between experimental adjuvant arthritis following ibuprofen treatment and morphological alterations of the parotid glands in rats. Freud's adjuvant was injected intradermally into the plantar surface of the hind paw of the animals to induce experimental arthritis. Ibuprofen was administrated per os (17 mg/kg/day). Both adrenals and parotid glands were isolated and their absolute and relative weights were evaluated. A full histological examination of parotid glands took place. The diameter of the foot as well as the serum levels of rheumatoid factor was measured. In conclusion, both experimental adjuvant arthritis and ibuprofen treatment induce morphological changes of the parotid tissues, which are related to macro- and micro-structure of the gland.

Stress-induced lidocaine modification in serum and tissues

The aim of this study is to examine the influence of acute (trauma) and chronic (cold swimming and adjuvant rheumatoid arthritis) stress on lidocaine concentrations in plasma. Forty male Wistar rats were used. The animals were divided into four groups. Group A served as control. Group B underwent mandible osteotomy. Group C was submitted to swimming stress in cold water 4 degrees C for ten minutes daily for 15 minutes, while group D underwent experimental arthritis with Freud's adjuvant. All groups received lidocaine i.m (2.5 mg/kg). Blood samples were collected and FFA (free fatty acid), unbound-lidocaine, albumin and a1-acid glycoprotein concentrations were estimated. Furthermore, the adrenals, heart and liver were isolated. The adrenals' relative weight (adrenal weight/body weight) was assessed, while lidocaine concentrations in the heart and the liver incubation medium were measured by intertechnic a-counter. Lidocaine and FFA levels in serum as well as the adrenal weights demonstrated a significant elevation in stress-groups as compared to the control group. Furthermore, in the stress-groups, lidocaine concentrations in heart tissue were significantly increased, whereas in the liver they were significantly reduced as compared to the control group. Our results indicate that stress can alter lidocaine levels in plasma and tissues, suggesting that stress should be considered an important factor when determining the dosage of lidocaine in clinical application.

Interaction between nandrolone decanoate and calcitonin in bone formation markers (osteocalcin and bone specific alkaline phosphatase) and IGF-I in rats

Bone tissue has been shown to contain numerous cell-to-cell signaling peptides called growth factors. These growth factors are thought to have important regulating effects for bone remodeling, due to their potent effects on bone cell metabolism. Our investigation was intended to assess the effect of nandrolone decanoate and calcitonin treatment on biochemical markers of bone formation (bone alkaline phosphatase - osteocalcin) and insulin-like growth factor-I in rats. We studied 48 adult male rats. The animals were divided into four groups. Group (A) served as control. Animals in Group (B) were injected with 4 mg/kg/day nandrolone decanoate. Animals in Group (C) were injected with 400mU/rat/day calcitonin and Group (D) received combined therapy for seven days. Nandrolone decanoate and calcitonin have a mild but significant effect on insulin-like growth factor-I without affecting osteocalcin levels, while calcitonin alone decreases the BALP levels. The coadministration of two agents caused notable elevation on insulin-like growth factor-I, followed by a significant increase of osteocalcin and bone alkaline phosphatase.

Masseteric hypertrophy associated with administration of anabolic steroids and unilateral mastication: a case report

In this report we present a patient with unilateral masseteric hypertrophy who used anabolic steroids and was chewing entirely unilaterally for 1 month. Computed tomography and histologic examination were used to confirm the diagnosis. The combined action of unilateral mastication and anabolic steroid use is probably responsible for the rapid development of unilateral masseteric hypertrophy.

Changes of Serum and Tissue Amoxicillin Levels Following Chlorpromazine Administration in Rats

Patients under treatment with chlorpromazine (CPZ) may need antibacterial administration. Amoxicillin is the most widely used antibacterial agent in dental infections. The aim of this study was to investigate the possible interactions between amoxicillin and CPZ and the eventual changes in amoxicillin levels using an experimental model in rats. Thirty male Wistar rats weighing 200-260 g were used for this study. They were divided into three groups: group A taking 15 mg/kg amoxicillin every 8 h for 4 days; group B taking amoxicillin as group A, and 1.07 mg/kg CPZ every 8 h for 4 days; and group C taking only CPZ in the same dose as group B. Drugs were given per os for 4 days, using a special catheter. The rats were sacrificed 2 h after the last dose. Antibacterial levels were estimated in blood serum, jaw bones, tongue and liver. An increase in the level of amoxicillin in serum as well as in tissues was observed in group B. No significant antibacterial activity of CPZ was detected. The increase in amoxicillin concentration in serum and jaws of group B was statistically significant in relation to group A.