Contrast-enhanced spiral CT of the liver: effect of injection time on time to peak hepatic enhancement

PURPOSE

On contrast-enhanced hepatic CT, maximum tumor detection of liver metastases from colorectal cancer is achieved at peak hepatic enhancement. We investigated the relationship between injection time of contrast medium and time to peak hepatic enhancement (TPHE) after the end of injection.

METHOD

One hundred nineteen patients without a cardiovascular disorder were enrolled in this study. Before the spiral CT was performed, a small amount of contrast medium was injected and a single level dynamic CT was performed to evaluate aortic enhancement and to determine the scan start time of the spiral examination. Patients were divided into three groups; contrast medium was injected over 30 s in 40 patients (Group A), 45 s in 39 patients (Group B), and 60 s in 40 patients (Group C). The TPHE after the end of injection was measured, and the difference among the groups was compared using one-way analysis of variance. A p value of <0.05 was considered a statistically significant difference.

RESULTS

The TPHEs of the groups were 25.3 +/- 4.6 s (Group A), 27.0 +/- 5.8 s (Group B), and 24.4 +/- 4.6 s (Group C) and were similar in value. No statistically significant difference was observed (p = 0.067).

CONCLUSION

Hepatic enhancement reaches its peak at approximately 25 s after the end of contrast medium injection irrespective of injection time.

[Peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations]

We studied peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations (CCPO), which included pulmonary resection and coronary artery bypass grafting (CABG). Of eight patients who had lung cancer and ischemic heart disease (IHD), six underwent CCPO and two patients first had percutaneous transluminal coronary angioplasty (PTCA) followed by lung surgery at an interval after the first procedure. Twelve patients with lung cancer who underwent only pulmonary surgery and 13 patients with IHD who were treated with CABG were studied as controls. We compared peri- and postoperative characteristics among these groups of patient. Operating time, bleeding volume during surgery, amount of drainage discharge within 24 hours after the operation, and ICU days were significantly increased in the CCPO group in comparison with the two control groups. In the CCPO group, mechanical ventilatory support time and administration days after the operation were significantly increased in comparison with the lung operation group, but not in comparison with CABG group. The two patients who sequentially underwent PTCA and lung surgery had postoperative courses similar to the CCPO patients. All CCPO patients were ambulatory upon discharge. None of the CCPO patients died from postoperative complications involving the respiratory tract or the circulatory system. Our data suggest that CCPO is available for patients with both heart and lung diseases when complications can be avoided by appropriate management, although these procedures are extremely invasive. We believe that CCPO should be attempted in patients with definite indications for such a procedure.

Synthesis and modification of a novel 1 beta-methyl carbapenem antibiotic, S-4661

We describe an efficient method for introducing a sulfamoylamino group into the C-2' position of pyrrolidine using the Mitsunobu reaction. S-4661, its N-methyl analogues and stereoisomers were synthesized using this method and their structure-activity relationships were investigated.

Extended intraarterial cisplatin infusion for treatment of gynecologic cancer after alteration of intrapelvic blood flow and implantation of a vascular access device

PURPOSE

Twenty-two patients with advanced gynecologic cancer underwent extended intraarterial cisplatin infusion after alteration of the intrapelvic blood flow and implantation of a vascular access device (VAD).

METHODS

To maximize concentrations of cisplatin at the target lesion, the superior and inferior gluteal arteries were embolized with steel coils. The tip of the catheter was inserted into the internal iliac artery; the opposite end of the catheter was connected to the VAD.

RESULTS

Intensive radioisotope accumulation was demonstrated in the anterior division of the pelvis, seen by scintigraphy performed with technetium 99m macroaggregated albumin via the VAD. Local perfusion in the tumor was well seen by ultrasonographic angiography with CO2 microbubbles via the VAD. Continuous consecutive infusion of cisplatin at a rate of 12.5 mg/day via the VAD minimized the toxicity. The overall response rate was 73%. Radical surgery was possible in 16 of the 22 patients after this intraarterial infusion.

CONCLUSION

This method was useful for treating advanced gynecologic cancer without significant toxicity.

Brain acetylcholinesterase activity: validation of a PET tracer in a rat model of Alzheimer's disease

We developed three radioactive acetylcholine analogs--N[14C]methyl-4-piperidyl acetate ([14C]MP4A), propionate ([14C]MP4P) and isobutyrate ([14C]MP4IB)--as radiotracers for measuring brain acetylcholinesterase (AchE) activity in vivo. The principle of our method is that the lipophilic analog diffuses into the brain where it is metabolized by AchE to produce a hydrophilic metabolite, which is trapped at the site of its production. The purpose of this study was to examine whether the tracers would have the sensitivity needed for early diagnosis of Alzheimer' disease using rats with a unilateral lesion in the nucleus basalis magnocellularis (NBM), an animal model of the cholinergic deficit in Alzheimer's disease.

METHODS

Rats with a unilateral NBM lesion were prepared, and the N[14C]methyl-4-piperidyl esters and N-Isopropyl-p-[123I]iodoamphetamine([123I]IMP were injected intravenously 30 and 2 min, respectively, before the rats were killed. Uptake of 14C and 123I and AchE activity in the lesioned and unlesioned (control) sides of the cortex were measured simultaneously.

RESULTS

The NBM lesion showed reduced cortical AchE activity by 30%-50%, with no side-to-side differences in [123I]MP uptake. Autoradiographic studies showed that uptake of 14C from [14C]MP4A and [14C]MP4P was significantly lower in the lesioned than unlesioned side of the cortex, which agreed well with the AchE histochemical staining patterns. Tissue dissection studies showed different uptake changes for the three compounds when AchE activity in the lesioned side of the cortex was reduced by 50%: 14C uptake from [14C]MP4P, [14C]MP4A and [14C]MP4IB was reduced by 27%, 21% and 7.3%, respectively. Theoretical analysis of the observed sensitivities of the tracers in relation to their in vitro enzymatic properties indicated that tracer sensitivity was highly dependent on the enzymatic hydrolysis rate of the tracer.

CONCLUSION

The [14C]MP4A and [14C]MP4P esters had sufficient sensitivity to enable AchE activity changes in the rat cortex of less than 50% to be detected, indicating that the present method is applicable to PET diagnosis of Alzheimer's disease.

Possible enhancing mechanism of the cutaneous permeation of 4-biphenylylacetic acid by beta-cyclodextrin derivatives in hydrophilic ointment

The enhancing effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the percutaneous absorption of 4-biphenylylacetic acid (BPAA), a nonsteroidal anti-inflammatory drug, in hydrophilic ointment were studied and compared with the parent beta-cyclodextrin (beta-CyD). 13C-NMR measurements suggested that the biphenyl group of BPAA is preferably included within the cavity of three beta-CyDs. The three beta-CyDs remarkably enhanced the release of BPAA from the hydrophilic ointment base and the in vitro cutaneous permeation, depending on the increase in solubility of BPAA in the ointment base. Pretreatment of the ointment containing DM-beta-CyD or HP-beta-CyD onto the isolated skin of hairless mice, however, provided no effects on the skin permeation of BPAA. When propylene glycol was used as a vehicle, both the release rate and cutaneous permeation parameters showed no appreciable difference between BPAA alone and its HP-beta-CyD complex, because the solubilities of BPAA and its HP-beta-CyD complex were almost comparable in the vehicle. The present results suggested that the enhancing effect of beta-CyDs on the percutaneous absorption of BPAA can be mainly ascribed to an increase in the solubility of BPAA in the hydrophilic ointment.

A novel 1 beta-methylcarbapenem antibiotic, S-4661. Synthesis and structure-activity relationships of 2-(5-substituted pyrrolidin-3-ylthio)-1 beta-methylcarbapenems

The synthesis and biological activity of (1R,5S,6S)-2-[(3S,5S)-5-substituted pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1- methylcarbapen-2-em-3-carboxylic acids are described. These compounds exhibit potent antibacterial activity against a wide range of both Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa. Of these new carbapenems, (1R,5S,6S)-2-[(3S,5S)-5-sulfamoylaminomethyl pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1-methylcarb apen- 2-em-3-carboxyli c acid (S-4661) showed the most potent and well balanced activity and was selected as a candidate for further evaluation.

Time courses of changes in cerebral blood flow and blood-brain barrier integrity by focal proton radiation in the rat

In order to know the pathophysiological mechanisms underlying radiation brain injury, cerebral blood flow and blood-brain barrier integrity were studied using N-isopropyl-p-[123l]iodoamphetamine (IMP) and [14C]-alpha-aminoisobutyric acid (AIB), respectively, in the rat focal proton radiation model (a single dose of 30 or 60 Gy radiation with 70 MeV proton beams). One, 2, 4, and 5.5 months after irradiation, [123l]IMP and [14C]AIB were intravenously injected and uptake of IMP and AIB in the cerebral cortex, striatum, hippocampus, and thalamus was measured. Significant decreases in IMP uptake were observed in the cerebral cortex and thalamus of the irradiated side at 4 and 5.5 months after 60 Gy irradiation; the effects at 5.5 months were more prominent than those at 4 months. AIB uptake markedly increased in all the brain regions of the irradiated side at 5.5 months after 60 Gy irradiation, and at 4 months, only in the hippocampus. The results suggest that there are dose- and time-dependent responses in radiation effects and regional differences in tissue vulnerability to radiation. Proton focal radiation model appears to be a useful model for studies of radiation brain injury in small animals such as rats.

Combination effects of alpha-cyclodextrin and xanthan gum on rectal absorption and metabolism of morphine from hollow-type suppositories in rabbits

Pharmacokinetics of morphine and its glucuronides in plasma were studied after rectal administration of hollow-type oleaginous suppositories containing kneading mixtures of morphine hydrochloride, alpha-cyclodextrin, and/or xanthan gum in rabbits. In combination with xanthan gum, alpha-cyclodextrin reduced the first-pass metabolism of morphine in the rectal mucosa and by the liver and improved the apparent rectal bioavailability of the opioid about 4 fold. In vitro permeation studies using an isolated rectal mucosal preparation of rabbits revealed that alpha-cyclodextrin increased the transepithelial conductance and facilitated the transport of morphine through the rectal mucosa. Furthermore, alpha-cyclodextrin facilitated its own mucosal permeation and reduced the glucuronidation of morphine during the passage through the rectal mucosa, probably through restricting the formation of a catalytic complex of morphine with glucuronyltransferases, rather than because of the enzyme saturation. The present data suggest that alpha-cyclodextrin in combination with xanthan gum is particularly effective in improving the rectal bioavailability of morphine from hollow-type suppositories.

Enhanced nasal delivery of luteinizing hormone releasing hormone agonist buserelin by oleic acid solubilized and stabilized in hydroxypropyl-beta-cyclodextrin

The potential use of three 2-hydroxypropyl ether derivatives of cyclodextrins (HP-alpha-, HP-beta- and HP-gamma-CyDs) as biocompatible solubilizers and stabilizers for oleic acid, a lipophilic absorption enhancer, was assessed in the nasal absorption of buserelin, an agonist of luteinizing hormone-releasing hormone, in rats. HP-CyDs increased the aqueous solubility of oleic acid and protected it against oxidation through the formation of inclusion complexes with the efficacy increasing in the order: HP-gamma-CyD << HP-alpha-CyD < HP-beta- CyD. The bend structure due to a cis-double bond halfway along the acyl chain of oleic acid provided a better fit into the cavity of HP-beta-CyD, in which the double bond appears to be buried, and hence becomes less susceptible to oxidation. The rate and extent of nasal bioavailability of buserelin were remarkably increased by coadministration of oleic acid and HP-beta-CyD, compared with the sole use of the enhancer. This enhancement was ascribable to the lowering of both the enzymatic and physical barriers of the nasal epithelium to the peptide, probably through the facilitated transmucosal penetration of oleic acid solubilized in HP-beta-CyD.

Simplified PET quantitation of myocardial glucose utilization

The purpose of this study was to validate experimentally a simple method to quantify tissue glucose utilization with the brain reference index (BRI) using 14C-deoxyglucose and assess its clinical feasibility for myocardial PET.

METHODS

To validate the BRI method, glucose utilization in myocardial and skeletal muscle was studied in rats with 14C-deoxyglucose after increasing doses of oral glucose loading. To assess clinical feasibility of the method, the BRI was applied to nine patients undergoing myocardial PET and compared to rMGU measured by the deoxyglucose model of Sokoloff et al. and by Patlak graphical analysis. The normal range of myocardial FDG uptake expressed as the BRI was estimated with four normal volunteers.

RESULTS

In skeletal muscle, a dose-dependent increase of glucose utilization was observed during oral glucose loading with doses up to 4 mg/g. In the myocardium, glucose utilization increased with a glucose loading dose of up to 1 mg/g without increasing further at greater glucose doses. Ratios of maximal glucose utilization in glucose-loaded rats to 19-hr fasted rats (controls), expressed as the BRI for left and right ventricular myocardium and skeletal muscle were 4.16, 3.74 and 7.39, respectively. Glucose utilization of right ventricular myocardium was approximately 70% of left ventricular myocardium for all glucose-loaded conditions. For patients, the BRI correlated with rMGU; four of these patients had a constant plasma glucose concentration.

CONCLUSION

Myocardial BRI is a sensitive indicator of rMGU that does not require dynamic data acquisition or constant plasma glucose concentrations.

Improvement of nasal bioavailability of luteinizing hormone-releasing hormone agonist, buserelin, by cyclodextrin derivatives in rats

The effects of chemically modified cyclodextrins on the nasal absorption of buserelin, an agonist of luteinizing hormone-releasing hormone, were investigated in anesthetized rats. Of the cyclodextrins tested, dimethyl-beta-cyclodextrin (DM-beta-CyD) was the most effective in improving the rate and extent of the nasal bioavailability of buserelin. Fluorescence spectroscopic studies indicated that the cyclodextrins formed inclusion complexes with buserelin, which may reduce the diffusibility of buserelin across the nasal epithelium and may participate in the protection of the peptide against enzymatic degradation in the nasal mucosa. Additionally, the cyclodextrins increased the permeability of the nasal mucosa, which was the primary determinant based on the multiple regression analysis of the nasal absorption enhancement of buserelin. Scanning electron microscopic observations revealed that DM-beta-CyD induced no remarkable changes in the surface morphology of the nasal mucosa at a minimal concentration necessary to achieve substantial absorption enhancement. The present results suggest that DM-beta-CyD could improve the nasal bioavailability of buserelin and is well-tolerated by the nasal mucosa of the rat.

Structures of genomic and complementary DNAs coding for Pleurotus ostreatus manganese (II) peroxidase

To study the mechanism of regulation and structure/function relationship of the Pleurotus ostreatus manganese (II) peroxidase (MnP), we amplified the full-length genomic and complementary DNAs for the major isozyme of the MnP mainly by the cassette-primer PCR technique and then sequenced them. The cDNA contained an open reading frame of 1083 bp encoding for a polypeptide of 361 amino-acid residues, including the suggested signal peptide of 29 amino-acid residues with a prepro structure. The predicted amino-acid sequence of the protein shared several common characteristics with those of fungal lignin and manganese (II) peroxidases. We could find a suggested metal response element and two heat-shock element-like sequences in the 5'-flanking region of the structural gene. The structural gene contained 15 introns, many of which lie identical to those in lignin peroxidase genes rather than to those in the known MnP genes.

[Daily oral low-dose etoposide therapy for aged patients with relapsed aggressive lymphoma]

Two patients with relapsed Non-Hodgkin's lymphoma (NHL) were treated with oral administration of etoposide. In these patients, long-term hematological remission was obtained. One patient was a 76-year-old man, who was successfully treated with CHOP for diffuse large cell NHL stage III B. One year after obtaining CR, he was admitted to our hospital for enlargement of lymph node. Rebiopsy of lymph node made a diagnosis of relapse from NHL. A new regimen of oral administration of etoposide treatment was employed. Hematological remission was obtained and continued for 3 years. Without interfering with his quality of life. The other patient was a 74-year-old man, who was treated with 6 cycles of CHOP for diffuse large cell NHL stage IV B. The patient attained complete remission following an additional 2 cycles of COMLA therapy. Eight years later, he was admitted for enlargement of lymph node. Rebiopsy of lymph node provided the basis for a diagnosis of relapse from NHL. Oral administration of etoposide treatment was started. Hematological remission was obtained and has been continued until now. These results show that oral administration of etoposide treatment is effective for some patients with recurrent NHL.

CT evaluation of hepatic tumors: comparison of CT with arterial portography, CT with infusion hepatic arteriography, and simultaneous use of both techniques

OBJECTIVE

We hypothesized that CT with arterial portography (CTAP) might depict tumors undetected by CT with infusion hepatic arteriography (CTIHA), and the converse. Accordingly, we compared the detection rate of malignant tumors using CTAP, CTIHA, and simultaneous use of both techniques to determine whether CTIHA can be used to distinguish malignant from benign hepatic nodules.

SUBJECTS AND METHODS

Fifty-four candidates for partial liver resection who underwent combined CTAP and CTIHA were studied. Histopathologic study confirmed 77 malignant and 15 benign nodules in these patients. CTAP, CTIHA, and combined CTAP and CTIHA were used by three observers before surgery, and the sensitivities of the three methods in detecting malignant tumors were compared. Contrast-enhancement patterns of the nodules on CTIHA scans were determined.

RESULTS

Sixty-eight malignant nodules (88%) were detected with CTAP, 64 (83%) with CTIHA, and 69 (90%) with simultaneous interpretation of both scans. These differences were not significant. CTIHA showed 16 malignant and 12 benign small nodules. Of these, 13 malignant and two benign nodules had rim enhancement. Use of rim enhancement as the criterion for malignancy of these small nodules gave an accuracy rate of 82%.

CONCLUSION

CTAP, CTIHA, and simultaneous use of both techniques are similar in their ability to detect malignant hepatic tumors. CTAP alone is recommended for the detection of malignant hepatic tumors. CTIHA is of value in differentiating malignant from benign small nodules.

Direct measurement of high-density lipoprotein cholesterol in serum with polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin

We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective catalytic activities towards lipoprotein fractions, with the reactivity increasing in the order: low-density lipoprotein < very-low-density lipoprotein approximately chylomicron < HDL. In the presence of magnesium ions, alpha-cyclodextrin sulfate reduced the reactivity of cholesterol, especially in chylomicrons and very-low-density lipoprotein, without the need for precipitation of those lipoprotein fractions. The combination of PEG-modified enzymes with alpha-cyclodextrin sulfate provided selectivity for the determination of HDL-cholesterol in serum in the presence of a small amount of dextran sulfate without the need for precipitation of lipoprotein aggregates. The results of the HDL-cholesterol assayed in serum by this direct method correlated well with those obtained by precipitation-based methods and also that by an ultracentrifugation method.

Direct measurement of high-density lipoprotein cholesterol in serum with polyethylene glycol-modified enzymes and sulfated alpha-cyclodextrin

We have developed an automated method for measuring high-density lipoprotein (HDL)-cholesterol in serum without prior separation, using polyethylene glycol (PEG)-modified enzymes and sulfated alpha-cyclodextrin. When cholesterol esterase and cholesterol oxidase enzymes were modified with PEG, they showed selective catalytic activities towards lipoprotein fractions, with the reactivity increasing in the order: low-density lipoprotein &lt; very-low-density lipoprotein approximately chylomicron &lt; HDL. In the presence of magnesium ions, alpha-cyclodextrin sulfate reduced the reactivity of cholesterol, especially in chylomicrons and very-low-density lipoprotein, without the need for precipitation of those lipoprotein fractions. The combination of PEG-modified enzymes with alpha-cyclodextrin sulfate provided selectivity for the determination of HDL-cholesterol in serum in the presence of a small amount of dextran sulfate without the need for precipitation of lipoprotein aggregates. The results of the HDL-cholesterol assayed in serum by this direct method correlated well with those obtained by precipitation-based methods and also that by an ultracentrifugation method.

Retrievable IVC filter: preliminary in vitro and in vivo evaluation

PURPOSE

To develop an inferior vena cava (IVC) filter that is retrievable even after neointimal formation and incorporation into the caval wall.

MATERIALS AND METHODS

Eight filters were placed percutaneously in the infrarenal IVC of eight dogs. Four weeks after placement, percutaneous retrieval of the filters was attempted. Vena cavograms were obtained before and immediately after retrieval. Three dogs were killed immediately after the retrieval procedure was completed. In the other five dogs, follow-up vena cavography was performed 4-14 weeks after retrieval, and autopsy was performed.

RESULTS

The filters were placed and retrieved successfully in all eight dogs. No migration, caval penetration, or tilting occurred. The IVCs were completely patent both before and immediately after retrieval in all eight dogs. In the three dogs killed immediately after retrieval, neointimal hyperplasia was seen around the struts, but there was no detachment. Delayed stenosis was not seen in any of the five dogs that were followed up, and the inner surface of the caval wall was smooth.

CONCLUSION

This IVC filter can be easily placed and safely retrieved percutaneously, even after neointimal formation.

Gianturco stent placement in malignant caval obstruction: analysis of factors for predicting the outcome

PURPOSE

To determine the factors that may be used to predict outcome of stent placement in patients with malignancies obstructing the superior or inferior vena cava.

MATERIALS AND METHODS

Gianturco stents were placed in 39 patients with malignant obstruction of the superior (n = 16) or inferior (n = 23) vena cava. Thirteen patients with obstruction of the superior vena cava received radiation therapy and/or chemotherapy at some time in their course of treatment. Computed tomographic (CT) scans were obtained in all patients. The authors analyzed treatment outcome with the location, length, and CT appearance of obstruction.

RESULTS

Venous congestive symptoms disappeared after stent placement in 35 patients and remained in four. Symptoms did not recur during 1-13-month follow-up in 32 of the 35 patients in whom the symptoms disappeared. Nonfatal complications were observed in nine patients. Results of multivariate analysis showed that the outcome of stent placement is best predicted by the appearance of obstructions on CT scans irrespective of the location and length of the lesions.

CONCLUSION

Good results can be expected from placement of Gianturco stents except when CT shows the obstruction to be totally enveloped by tumor.

Adrenergic receptor-mediated Cl- transport in rabbit corneal endothelial cells

Adrenoceptor-mediated Cl- transport in cultured rabbit corneal endothelium was examined using a Cl(-)-sensitive fluorescent dye. The intracellular Cl- concentration ([Cl-]i) in the endothelial cells was estimated to be about 30 mM. Noradrenaline (0.001-0.1 mM) transiently decreased the [Cl-]i in a dose-dependent manner. Such a decrease in [Cl-]i was completely antagonized by pretreatment with the alpha-adrenoceptor antagonist phentolamine (0.1 mM). The selective alpha 2-adrenoceptor agonist UK 14304-18 (5-bromo-6-[(4H,5H-imidazol-2-yl)amino]quinoxaline, 0.1 mM) persistently decreased the [Cl-]i, but neither the alpha 1-adrenoceptor agonist phenylephrine (0.1 mM) nor the beta-adrenoceptor agonist isoproterenol (0.1 mM) had any effect. The alpha 2-adrenoceptor agonist/antagonist yohimbine (0.1 mM) persistently and more strongly decreased the [Cl-]i than UK 14304-18 did. The yohimbine-induced decrease in the [Cl-]i was not further altered by UK 14304-18 or phenylephrine, but partly reversed by noradrenaline, isoproterenol and an adenylate cyclase activator, forskolin (0.1 mM). The yohimbine-induced decrease in [Cl-]i was inhibited by the carbonic anhydrase inhibitor acetazolamide (1 mM), and Cl-/HCO3- exchange inhibitors, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, but not by the H(+)-ATPase inhibitor N,N'-dicylohexylcarbodiimide. The forskolin-induced recovery in [Cl-]i was inhibited by the Na+/K+/Cl- cotransport inhibitor bumetanide (0.1 mM), but not by the Cl- channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of the time to peak hepatic enhancement to optimize contrast-enhanced spiral CT

A technique for the prediction of the time to peak hepatic enhancement to optimize contrast-enhanced spiral CT has been developed. The procedures are (a) to inject a small amount of contrast medium rapidly via the antecubital vein and measure aortic transit time (ATT) of the bolus by single slice dynamic CT; (b) to inject contrast medium at a high rate, expecting peak hepatic enhancement to occur at ATT plus 8 seconds after the end of injection; (c) to perform spiral scanning of the liver using thin collimation and caudo-cranial table movement beginning at ATT after the end of contrast medium injection.

Postsurgical intrahepatic portal thromboembolism: a possible cause of perfusion defects on CT during arterial portography

OBJECTIVE

Our goal was to investigate unexplained nontumorous perfusion defects on CT arterial portography (CTAP).

MATERIALS AND METHODS

The CTAP images of 35 patients who underwent partial hepatectomy or open biopsy were analyzed. Hepatic tumors consisted of hepatocellular carcinoma (n = 18) and colorectal carcinoma metastases (n = 17). Nontumorous perfusion defects were categorized into those previously explained and those unexplained. We investigated unexplained ones and their relationship with the underlying conditions.

RESULTS

Eight unexplained nontumorous perfusion defects were found in four patients with colorectal metastases. Statistical analysis showed that the defects occurred with significantly higher incidence in patients with colorectal metastases than in those with hepatocellular carcinoma (p = 0.046, Fisher test). All four patients with defects underwent CTAP within 1 month after colorectal surgery. A significant difference was seen in the distribution of surgery-CTAP time intervals between those patients with and those without defects (p < 0.05, Wilcoxon-Mann-Whitney test). Intrahepatic portal thrombi were pathologically proven in one of the four patients.

CONCLUSION

Unexplained nontumorous hepatic perfusion defects may represent postsurgical portal thromboemboli.

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations in elderly men and women

The effects of long-term low intensity aerobic training and detraining on serum lipid and lipoprotein concentrations were examined in 30 elderly men and women. These subjects were randomly divided into two groups. The training group [n = 15; 7 men and 8 women; mean age 75.5 (SD 5.6) years] agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate concentration threshold for 30 min 3-6 times a week for 9 months. The other group [n = 15; 7 men and 8 women; mean age 73.7 (SD 4.4) years] did not perform any particular physical training and was followed as the control. Following this training period the high density lipoprotein-cholesterol (HDL-C) had increased significantly (P < 0.01) while the total cholesterol (TC):HDL-C ratio had decreased significantly (P < 0.01) in the training group after 9 months but had not changed in the control group. The TC, triglyceride (TG) and low density lipoprotein-cholesterol (LDL-C) had not changed significantly in either group. No significant difference was seen between the groups throughout the period for TC. LDL-C or TG. There was, however, a significant correlation between the initial TC:HDL-C ratio and the change in the TC:HDL-C ratio following 3 months of training (P < 0.05). After 1 month of detraining in 5 patients, the HDL-C had decreased significantly (P < 0.05) while the TC:HDL-C had increased significantly in the training group (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)