Image quality and radiation dose of renal perfusion CT with low-dose contrast agent: a comparison with conventional CT using a 320-row system.

AIM: To compare perfusion computed tomography (CT) with reconstructed image from source data using low-dose contrast agent and conventional 320-row CT for the evaluation of renal tumours. MATERIALS AND METHODS: Twenty-eight patients underwent conventional CT (C-CT) and 26 patients underwent perfusion CT with low-dose (40 ml) contrast agent. Image noise, arterial visualisation, the sharpness of the corticomedullary junction (CMJ), and overall image quality were each assessed using a four-point scale. The tumour detection rate for lesions <4 cm (n=66) was also evaluated. Quantitative image parameters including image noise and the contrast-to-noise ratios (CNRs) of the renal artery and CMJ were measured. The volume CT dose index (CTDI), dose-length product (DLP), and size-specific dose estimate (SSDE) were also recorded. RESULTS: Although the image noise of perfusion CT was higher than that of C-CT and the overall image quality of perfusion CT was lower than that of C-CT, the arterial visualisation score of perfusion CT was significantly higher than that of C-CT. The CMJ sharpness scores of the two techniques were equivalent. Sensitivity and positive predictive values were also equivalent with respect to tumour detection. The CNRs of both the left and right renal arteries were significantly higher on perfusion CT than on C-CT. The CTDI, DLP, and SSDE of perfusion CT were significantly lower than those of C-CT. CONCLUSION: Perfusion CT using low-dose contrast agent preserved arterial visualisation and the tumour detection rate and achieved a low radiation dose despite image quality degradation and image noise.

Predictors of therapeutic effect of transarterial chemoembolisation using drug-eluting beads for hepatocellular carcinoma.

AIMS: To identify predictors of a therapeutic effect after transarterial chemoembolisation using drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Between January 2015 and July 2015, tumour variables and angiographic data were collected for 25 patients (49 target lesions) after they had undergone the DEB-TACE procedure for HCC. The therapeutic effect was evaluated according to the Response Evaluation Criteria in Cancer of the Liver at follow-up dynamic computed tomography (CT) performed within 1-4 months after the procedure. A p<0.05 was considered significant. RESULTS: On a target lesion basis, the objective response (TE3/4) rate was 63.3% (31 of 49). On univariate analysis, larger size (≥2 cm) was a predictor of an objective response (p=0.029). The tumour location of the medial (segment 4) or caudate (segment 1) lobe also indicated a poor therapeutic effect (TE1/2), but not at the level of significance (p=0.051). Multivariate analysis identified tumour size (odds ratio, 8.60; 95% confidence interval, 1.87-62.8) and tumour location (odds ratio, 12.2; 95% confidence interval, 2.12-129.8) as significant factors associated with a therapeutic effect. On a patient basis, 10 of 25 (40%) patients showed complete response/partial response. There were no significant differences between complete response/partial response and stable disease/progressive disease regarding age, gender, tumour markers, history of previous treatment, Child-Pugh class, T-stage, or Barcelona Clinic Liver Cancer Staging. CONCLUSION: A short-term therapeutic effect was associated with tumour size and location on a target lesion basis.

Heterogeneity of non-cancerous liver parenchyma on gadoxetic acid-enhanced MRI: an imaging biomarker for hepatocellular carcinoma development in chronic liver disease.

AIM: To clarify whether the heterogeneity of non-cancerous liver parenchyma (NLP) in the hepatobiliary phase on gadoxetic acid enhanced magnetic resonance imaging (MRI) is correlated with hepatocellular carcinoma (HCC) development. MATERIALS AND METHODS: Institutional review board approval was obtained, and the requirements for informed consent were waived for this retrospective study. The imaging characteristics of 84 patients with chronic liver disease who underwent gadoxetic acid-enhanced 3T MRI between January 2013 and October 2014 were examined retrospectively. For the evaluation of the heterogeneity of the intensity in the hepatobiliary phase, the largest possible region of interest was placed on the NLP, and the skewness and kurtosis were calculated using ImageJ software. Skewness is the degree of asymmetry of a histogram, and kurtosis is a measure of the peak. Based on the median values of kurtosis and skewness, the patients were classified into four categories and the categories were compared between the 49 patients with HCC (HCC group) and the 35 patients without HCC (non-HCC group). RESULTS: Kurtosis was significantly higher in the HCC group compared to the non-HCC group (1.19±1.15 versus 0.43±0.83; p=0.0006). Skewness was significantly lower in the HCC group than in the non-HCC group (1.19±1.15 versus 0.43±0.83; p=0.0152). In a multivariate logistic analysis, the category showing lower-than-the-median (-0.1185) skewness and higher-than-the-median (0.547) kurtosis was significantly and independently associated with HCC development (p=0.0031). CONCLUSION: The heterogeneity of NLP in the hepatobiliary phase on gadoxetic acid enhanced MRI may reflect the development of HCC.

Fatty change in moderately and poorly differentiated hepatocellular carcinoma on MRI: a possible mechanism related to decreased arterial flow.

AIM: To clarify the frequency of fatty change in moderately and poorly differentiated hepatocellular carcinomas (mHCCs and pHCCs) and its relationship to arterial blood flow. MATERIALS AND METHODS: One hundred and thirty-six surgically resected HCC lesions were studied. All patients had undergone dynamic magnetic resonance imaging (MRI) with chemical-shift-encoded water-fat imaging (CSI). The presence of fat was identified by a signal drop-off on CSI and confirmed at pathology. Lesions were classified into four groups in the arterial phase; G1, hypointense; G2, isointense; G3, slightly and heterogeneously hyperintense; G4, markedly and homogeneously hyperintense. The number of cumulative arteries (CAs) in the tumours in the pathology examination were counted. RESULTS: A fat component was observed significantly more frequently in the pHCCs (13/21; 61.9%) compared to the mHCCs (32/101; 31.7%; p=0.013). The numbers of lesions in each group were as follows: (G1, G2, G3, G4) = (18, 9, 23, 4) in the HCCs with fat; (1, 6, 24, 51) in the HCCs without fat (p<0.001); (5, 5, 18, 4) in the mHCCs with fat; (0, 3, 19, 47) in the mHCCs without fat (p<0.001); (11, 0, 2, 0) in the pHCCs with fat; (0, 2, 3, 3) in the pHCCs without fat (p=0.001). The number of CAs in the fat-containing HCCs (5.5±2.9) was significantly lower than that in the HCCs without fat (10.8±5.3; p<0.001). CONCLUSION: A fat component was more commonly observed in the pHCCs than in the mHCCs. The present results showed a possible mechanism of fatty change in mHCCs and pHCCs in relation to decreased arterial blood supply.

The features of clearance in recombinant factor IX (BeneFIX(®) ).

INTRODUCTION: Dosage adjustment is very important to perform continuous infusion (CI) of recombinant factor IX (rFIX) concentrates more effectively and economically, and clearance (CL) is strongly related to the infusion rate. However, previous reports have shown that the CL of rFIX concentrates varies widely (4.2-11.4 mL kg(-1) h(-1) ). AIM: The goal of this study was to gain a better understanding of the CL of the rFIX concentrate (BeneFIX(®) ) to precisely set the infusion rate of rFIX concentrates. METHODS: We estimated CLs by five different calculation approaches: from area under the blood concentration-time curve (AUC), from in vivo recovery (IVR) and half-life, from actual FIX activity value during CI, and from the simulation by one-compartment model in seven patients with haemophilia B. RESULTS: The mean CL calculated from AUC was 3.8 ± 0.4 mL kg(-1) h(-1) (range = 3.3-4.3 mL kg(-1) h(-1) ). CONCLUSION: The mean CL calculated from IVR and distribution half-life was 4.4 ± 0.4 mL kg(-1) h(-1) (range = 4.0-5.1 mL kg(-1) h(-1) ). The mean CL calculated from IVR and terminal half-life was 2.1 ± 0.5 mL kg(-1) h(-1) (range = 1.7-2.8 mL kg(-1) h(-1) ). The mean CL during CI was 4.9 ± 0.6 mL kg(-1) h(-1) (range = 4.2-5.6 mL kg(-1) h(-1) ). In addition, when we simulated the theoretical CL using a one-compartment model, the adjusted mean CL during CI was 4.8 ± 0.5 mL kg(-1) h(-1) (range = 4.0-5.4 mL kg(-1) h(-1) ). The CL obtained from distribution half-life was comparable to the CL during CI, while the CL calculated from terminal half-life did not reflect actual CL. Further, the rFIX concentrate was characterized by a one-compartment model under certain conditions.

Detectability of hepatocellular carcinoma on gadoxetic acid-enhanced MRI at 3 T in patients with severe liver dysfunction: clinical impact of dual-source parallel radiofrequency excitation.

AIM: To clarify the detectability of hepatocellular carcinoma (HCC) on gadoxetic acid-enhanced MRI at 3 T with dual-source parallel radiofrequency (RF) excitation. MATERIALS AND METHODS: Twelve patients with 26 HCCs who each underwent multidetector row CT (MDCT), gadoxetic acid-enhanced MRI with dual-source parallel RF excitation, and angiography-assisted CT prior to living related-liver transplantation. Three blinded readers independently reviewed the images obtained by each imaging technique for the presence of HCC on a segment-by-segment basis using a five-point confidence scale. The area under the receiver operating characteristic curve (Az), sensitivity, and specificity were compared among the three techniques. RESULTS: The Az values of gadoxetic acid-enhanced MRI were highest for all readers, although no significant difference in Az value among the three methods was obtained. No significant differences in sensitivity or specificity were observed among the three techniques for each reader. CONCLUSION: Gadoxetic acid-enhanced MRI at 3 T with dual-source parallel RF excitation has relatively high-level diagnostic potential for the detection of HCC in patients with severe liver dysfunction, which was equivalent to that of MDCT and angiography-assisted CT. Dual-source parallel RF excitation would have a clinical impact on 3 T MRI of the liver.

Two patients with focal segmental glomerulosclerosis complicated by cyclosporine-induced reversible posterior leukoencephalopathy syndrome.

Reversible posterior leukoencephalopathy syndrome (RPLS) is a distinctive clinicoradiological entity observed in a variety of clinical settings. Cyclosporine (CyA)-RPLS has been reported in a few patients with focal segmental glomerulosclerosis (FSGS); however, there had been no reports on developed RPLS after the re-administration of CyA treatment. We report two patients with FSGS who developed CyA-induced RPLS and summarize the results of a literature review for similar patients. The two patients with FSGS presented here were a 4-year-old boy and a 9-year-old boy, who presented with steroid-resistant nephrotic syndrome (NS) and were treated with CyA. The first patient developed CyA-induced RPLS at the 7th day after the start of CyA treatment, and the second patient at the 16th day after the re-start of CyA treatment. The two patients complained of a visual disorder and exhibited signs of a disturbance in consciousness and hypertension. Electroencephalography (EEG) examinations revealed a generalized slow wave pattern, and magnetic resonance imaging (MRI) disclosed an area of high signal intensity in the white matter. Subsequently, CyA was discontinued and neurological symptoms improved and recrudescence of RPLS did not occur. Our findings suggest that patients with FSGS and NS who are treated with CyA should be closely monitored for the possible onset of RPLS, presenting as a disturbance in consciousness, visual disturbances and/or convulsions.

Hepatic falciform ligament artery in patients with chronic liver diseases: detection on computed tomography hepatic arteriography.

BACKGROUND: The detection rate of hepatic falciform ligament artery (FLA) has been reported as ranging from 2-25%. The rate of FLA on laparotomy, however, is reported to be higher, at 68%. PURPOSE: To compare the detection rate of FLA on computed tomography hepatic arteriography (CTHA) with that on angiography and dynamic CT, and to clarify the clinical significance of FLA in patients with chronic liver disease. MATERIAL AND METHODS: 126 consecutive patients underwent CTHA angiography and dynamic CT to evaluate suspected liver tumors. Liver function was classified as follows: normal, n=5; Child-Pugh class A, n=94; B, n=21; and C, n=6. All CT images were obtained using multidetector (MDCT) scanners (Aquilion; Toshiba, Tokyo, Japan). For CTHA, CT images were obtained during contrast material injection through the left hepatic, proper, or common hepatic artery. On CT, FLAs were retrospectively identified within the hepatic falciform ligament and the hepatic round ligament by the paging method on a workstation (TWS-5000; Toshiba, Tokyo, Japan). The detection rates were compared among the three modalities (hepatic arterial phase of dynamic CT, CTHA, and angiography). The calibers of FLA were also correlated with the hepatic function of the patients. RESULTS: The detection rates of FLA by angiography, dynamic CT, and CTHA were 37% (47/126), 10% (13/126), and 77% (97/126), respectively. The calibers of FLA increased as the hepatic function deteriorated (P=0.001). CONCLUSION: The detection rates of FLA with CTHA are far higher than those with angiography and dynamic CT. Careful interpretation with recognition of FLA on CTHA images is important, as inadvertent embolization or chemotherapeutic infusion of the FLA may result in supraumbilical skin rash.

Microcoil embolization through a downsized coaxial catheter system: an experimental study.

BACKGROUND: Most of the recently developed microcatheters for abdominal angiography still have large diameters at their trailing ends, and thus cannot be used for microcoil embolization in combination with a 3-French (F) system. PURPOSE: To evaluate the in vitro passage of microcoils through a newly developed 2-F microcatheter (Meister Cath Superselective Plus, MC6) that is compatible with a downsized coaxial catheter system (3-F system) in an experimental study. MATERIAL AND METHODS: We evaluated the passage of microcoils through MC6 within a blood vessel model using the saline flush technique. Six types of microcoils and 17 size variations (maximal curled diameter 2-10 mm, total length 20-140 mm) were used. We evaluated the passage and post-deployment shape of the microcoils as well as the volume of saline required to flush them. RESULTS: In the experimental study, all microcoils passed through the MC6 and deployed in a satisfactory manner without catheter occlusion. The mean volumes of saline required to flush the TORNADO (n=1), Reverse TORNADO (n=6), HILAL (n=1), Micronester (n=3), VortX (n=4), and C-Stopper Coil (n=2) were 0.7 ml, 0.58+/-0.20 ml, 0.5 ml, 0.57+/-0.058 ml, 3.5+/-1.5 ml, and 0.70+/-0.14 ml, respectively. There was a statistically significant difference in the mean volume of saline required between the VortX and Reverse TORNADO (P=0.029), and between the VortX and C-Stopper Coil (P=0.031). The VortX required the greatest volume of saline. CONCLUSION: Microcoil embolization through a 3-F system appears to be feasible for the coils examined in this study.

Genomic and functional analyses of MUTYH in Japanese patients with adenomatous polyposis.

The present study was undertaken to elucidate germ line mutations of the base excision repair gene, MUTYH, in Japanese patients with adenomatous polyposis. We screened germ line mutations of adenomatous polyposis coli (APC) gene and MUTYH in 66 Japanese patients with adenomatous polyposis. APC was screened by the protein truncation test, while MUTYH was screened by polymerase chain reaction-based single-strand conformation polymorphism and direct sequencing. The nicking assay was applied in order to evaluate the DNA glycosylase activity of the identified MUTYH variant. In this study, Seven MUTYH variants were identified in 16 of 21 APC-negative patients. Q324H mutation was the most frequent mutation, with an allele frequency of 49%. Two patients carried biallelic mutations other than Q324H; a patient had biallelic G272E and A359V mutations, while the other had compound heterozygotes of P18L and G25D mutations. Nicking assay for G272E using the corresponding mouse MUTYH mutant with G257E revealed that G272E is a variant to cause an impaired DNA glycosylase activity. Homozygous MUTYH mutation accounts for approximately 10% of Japanese patients with adenomatous polyposis. G272E may be one of the mutations specific to patients with adenomatous polyposis in East Asia.

Chemiluminescence from human polymorphonuclear leukocytes activated with opsonized zymosan.

To prove the mechanism of photon emission during activation of leukocytes, a model system of human polymorphonuclear leukocytes (PMNs)-opsonized zymosan (OZ)-tyrosine (or none) or myeloperoxidase (MPO)-H2O2-tyrosine was employed, and three parameters-chemiluminescence yield and intensity, a metabolite such as bityrosine (BT), and chemiluminescence spectra-were studied. With the PMN system, the luminescence was enhanced by addition of tyrosine, its analogues, or albumin, but was inhibited by hydroxyurea, superoxide dismutase (SOD), or NaN3 (an inhibitor of MPO), indicating participation of tyrosine phenoxyl radicals, O2.- and MPO in the luminescence. With the PMN-OZ-tyrosine system, chemiluminescence yield was parallel to the BT formation. These results were essentially the same as those obtained with the MPO-H2O2-tyrosine system, except that luminescence from the latter system was not inhibited by SOD. When human albumin was exposed to the MPO-H2O2 system, BT was detected after hydrolysis of the protein in the mixture. Judging from the chemiluminescence spectra of activated PMNs and the MPO-catalyzed tyrosine oxidation, at least two excited species in triplet states-one for tyrosine and another for BT-would be generated in these systems. The luminescence may originate from the reaction of tyrosine phenoxyl radicals (cation radicals) with O2.- and/or peroxidase compound III (Fe...IIIO2.-).

Triphenyltin chloride inhibits superoxide production by human neutrophils stimulated with a surface active agent.

Treatment of human neutrophils with triphenyltin chloride (TPTCl)-inhibited superoxide (O-2) production stimulated with phorbol myristate acetate (PMA). TPTCl was more potent as inhibitor of O-2 production than other phenyltin compounds. The O-2 production by the xanthine oxidase-acetaldehyde system was not inhibited by TPTCl. This finding indicates that TPTCl does not itself react with O-2. Furthermore, TPTCl did not influence the isolated NADPH oxidase at all, though O-2 production of neutrophils stimulated with PMA in the presence of TPTCl was inhibited. These results indicate that TPTCl inhibits the activation process of the O-2 generating system.

Tracer accumulation in femoral head during early phase of bone scintigraphy after renal transplantation.

UNLABELLED: Nontraumatic osteonecrosis of the femoral head (ONF) is a complication of renal transplantation. The pathogenic mechanism of ONF is thought to be an ischemic event. The purpose of this study was to investigate whether 3-phase bone scintigraphy can reveal early hemodynamic changes associated with ONF after renal transplantation. METHODS: We performed 3-phase bone scintigraphy on 19 renal allograft recipients between 3 and 9 wk after they underwent renal transplantation. Regions of interest (ROI) were assigned bilaterally in the femoral heads, diaphyses, and soft tissue. The head-to-diaphysis ratio (HD) in each phase was then calculated. RESULTS: ONF occurred in 8 femoral heads of 4 patients. Three of the 4 ONF patients had no abnormal MRI findings at the time of bone scintigraphy. In phase 1, no significant difference in HDs was observed between the ONF patients (mean HD +/- SD, 0.62 +/- 0.44) and the non-ONF patients (0.31 +/- 1.40). The difference between the mean counts for bone and soft tissue was small in both instances, and the HD had a large dispersion. In phase 2, the HDs for the ONF patients (0.70 +/- 0.27) and the non-ONF patients (1.31 +/- 0.43) were significantly different (P = 0.0005). The HD was <1.00 in all femoral heads of the ONF patients, whereas 9 non-ONF heads had an HD that was <1.00. In phase 3, the HD of the ONF patients was significantly lower than that of the non-ONF patients (ONF patients, 0.92 +/- 0.17; non-ONF patients, 1.62 +/- 0.46; P = 0.0002). CONCLUSION: All ONF patients were in the group with a low HD in phase 2, suggesting a reduction in blood flow or blood pool. Phase 2 accumulation in 3-phase bone scintigraphy can be used to estimate early hemodynamic changes in patients with ONF after renal transplantation.

Increased subglottic gallium uptake in relapsing polychondritis.

Gallium scintigraphy was performed on a 14-yr-old girl with subglottic airway narrowing that caused wheezing and dyspnea. The study showed increased gallium uptake in the neck. A biopsy was performed on the subglottic region, and the histology was compatible with relapsing polychondritis. After treatment with steroids, laboratory data that had indicated active inflammation soon normalized. Repeat gallium scintigraphy showed diminished uptake, although the subglottic stenosis did not improve. These results suggest that gallium scintigraphy is valuable for evaluating inflammatory activity in relapsing polychondritis.

Detection of Borrelia duttonii, a tick-borne relapsing fever agent in central Tanzania, within ticks by flagellin gene-based nested polymerase chain reaction.

Argasid ticks collected in the site near Mvumi Hospital, Dodoma, Tanzania, were subjected to flagellin gene-based nested polymerase chain reaction (PCR) amplification for examination of borrelial infections. Eight of 13 ticks gave a strong 350-bp signal; three had a weak signal at the same size, and the rest were negative. Sequence determination of eight of the positive samples resulted in three types of flagellin gene sequences. The first type of sequence (shown by three individuals) was identical to that of Borrelia duttonii strain Ly. The second type of sequence from PCR products from four individual ticks had only one base substitution without amino acid alteration in deduced protein sequence. The third type of sequence was different from that of any other Old World relapsing fever borreliae, and the tick was thought to be infected with an unknown Borrelia species. Ticks were also examined to determine the nucleotide sequence of the mitochondrial 16S rRNA gene. The partial sequence of approximately 470 bases was aligned for comparison with previously published sequences to identify the species. The sequences of 13 individual ticks were all identical, and the sequence similarity analysis revealed the ticks should be classified as members of the Ornithodoros porcinus species. The PCR method described in this report appears to be a reliable tool for the detection of borreliae and epidemiological study of tick-borne relapsing fever.

Behaviour of urinary dipeptidase in patients with chronic renal failure.

Renal dipeptidase (EC 3.4.13.19) activity in serum and urine from healthy volunteers (n = 20), patients with diabetes (n = 18) and patients with chronic renal failure (n = 5) was measured using glycyl-D-alanine as substrate. The assay was highly specific for the enzyme and was not affected by the various aminopeptidases present in serum and urine. No difference in serum renal dipeptidase activity was observed between the groups. The enzyme activity (U/L) in urine was higher than that in serum, irrespective of the group, suggesting the urine concentration was not affected by the serum concentration. The mean renal dipeptidase activities in urine were 2.56, 2.46 and 0.78 U/mol creatinine for healthy subjects, patients with diabetes and patients with chronic renal failure, respectively. The renal dipeptidase activity was significantly lower in the chronic renal failure group. The urinary excretion of dipeptidase (U/mmol creatinine) showed significant inverse correlations with that of beta 2-microglobulin, albumin and alpha 1-microglobulin, and with serum concentrations of creatinine, beta 2-microglobulin and alpha 1-microglobulin. We suggest that urine dipeptidase may be a useful marker of renal diseases.

Small pulmonary arteriovenous fistulae revealed by scintigraphy during selective injection of 99Tc(m)-macroaggregated albumin.

We report a case of small pulmonary arteriovenous fistulae precisely diagnosed by a combination of selective pulmonary arteriography and scintigraphy during (99)Tc(m)-macroaggregated albumin injection via the peripheral pulmonary artery.

Utility of follow-up studies using meta-[123 I]iodobenzylguanidine scintigraphy for detecting recurrent neuroblastoma.

Neuroblastomas sometimes recur after the initial disappearance of the tumour. We evaluated the utility of meta-[123I]iodobenzylguanidine (123I-MIBG) scintigraphy for the detection of recurrent neuroblastomas by comparing with the measurement of biochemical markers and clinical findings. Forty patients who had received treatment for neuroblastomas were included in the study. After the disappearance of the initial tumours, periodic measurements of urinary vanillyl mandelic acid, homovanillic acid and serum neuron specific enolase values, and an 123I-MIBG scintigraphy were performed. Whenever an abnormal finding was observed, other appropriate examinations and/or follow-up examinations were performed to elucidate the true state of the patient. Eleven recurrent episodes in eight patients were observed. Most of them occurred in the bone marrow or bone. Corresponding symptoms were observed in only two episodes; the other episodes were asymptomatic, and discovered by the periodic examinations. 123I-MIBG scintigrams visualized the recurrent tumours in 10 (91%) episodes. Elevated tumour markers were observed in only three episodes. 123I-MIBG scintigrams visualized most of the recurrent tumours, unless they were accompanied by any symptoms or elevations in biochemical tumour markers. Periodic examinations with 123I-MIBG scintigraphy appears to be a useful technique for the detection of the recurrences.

Mitochondrial sequence variation in Carlos capensis (Neumann), a parasite of seabirds, collected on Torishima Island in Japan.

Partial mitochondrial 16S ribosomal ribonucleic acid gene sequences in the ticks Carios capensis collected from black-footed albatross. Diomedea nigripes, colonies on Torishima Island, Japan (30 degrees 28'N, 140 degrees 18'E), were examined. The sequence was compared with those of C. capensis from Hawaii, South Carolina, and Texas. The sequences were all identical in ticks from Torishima and 2 from Hawaii. There were 2-3 transitions between the other Hawaiian and Texas ticks and Torishima specimens. Two transitions were also observed when compared with the ticks from South Carolina. The results suggest the possibility of gene flow between tick populations at each of the 2 geographic sites, which probably was accomplished by tick-infested migratory seabirds at their breeding sites. Sequence comparison analysis indicated that the C. capensis ticks are on the branch with C. marginatus and C. mexicanus ticks and not with Ornithodoros. This supports the revision suggested by Klompen and Oliver (1993).

Blood flow and blood volume in the femoral heads of healthy adults according to age: measurement with positron emission tomography (PET).

OBJECTIVE: To deepen understanding of hemodynamics in the femoral head, i.e., the essential factor in clarifying pathogenesis of hip disorders, this study examined blood flow and blood volume in the femoral heads of healthy adults, and their changes with age, by using positron emission tomography (PET). METHODS: In 16 healthy adult males (age: 20-78 years old, mean age: 42 years), blood flow was measured by means of the H2(15)O dynamic study method, and blood volume was measured by means of the (15)O-labeled carbon monoxide bolus inhalation method. RESULTS: Blood flow was 1.68-6.47 ml/min/100 g (mean +/- SD: 3.52 +/- 1.2), and blood volume was 1.67-6.03 ml/100 g (mean +/- SD: 3.00 +/- 1.27). Blood flow significantly decreased (p < 0.01) with age, and blood volume significantly increased (p < 0.05). CONCLUSION: PET was useful in the measurement of blood flow and blood volume in the femoral heads. With age, physiological hemodynamic changes also increased in femoral heads.