SPECT imaging of normal subjects with technetium-99m-HMPAO and technetium-99m-ECD

Technetium-99m-HMPAO and 99mTc-ECD have been used for regional cerebral blood flow (rCBF) studies using SPECT. However, details of the normal perfusion patterns of these agents still remain to be clarified. HMPAO-SPECT and ECD-SPECT images of normal individuals were investigated using an anatomical standardization technique.

METHODS

Twenty healthy subjects participated in this study. In 10 of these, regional cerebral perfusion was measured with HMPAO, and in the other 10, ECD was used. All SPECT images were globally normalized to 50 counts/voxel, and then, each SPECT image was transformed into a standard brain anatomy format with the aid of x-ray CT of each subject and a computerized human brain atlas system (HBA). Mean and s.d. images for each tracer were calculated on a voxel-by-voxel basis. For comparison of these SPECT images with blood flow, rCBF images were generated using PET in a separate group of 10 healthy male subjects during an eyes-closed resting state. The PET images were globally normalized to 50 ml/100 g/min and anatomically standardized using each subject's MRI and the HBA for the SPECT images.

RESULTS

In the HMPAO-SPECT images, relatively high radioactivities Were observed in the basal ganglia and cerebellum. In the ECD-SPECT images, high levels were observed in the medial aspect of the occipital lobe. These regions with high radioactivity were not apparent in the rCBF-PET images.

CONCLUSION

While both HMPAO and ECD have been used to investigate rCBF, their perfusion patterns differ from rCBF-PET images. This presumably reflects differences in the mechanism of accumulation of each agent in the brain. For clinical diagnoses, these patterns must be taken into consideration.

Different roles of the left and right parahippocampal regions in verbal recognition: a PET study

We examined the role of the parahippocampal regions in humans during two types of verbal recognition process, i.e. delayed matching and non-matching, by measuring regional cerebral blood flow (rCBF) using PET. The results showed differential activation of each parahippocampal region during verbal memory tasks in which the side activated shifted depending on the nature of the task employed; an increase in rCBF in the left parahippocampal gyrus was associated with retrieval strategy of non-matching, and an increase in rCBF in the right parahippocampal gyrus was associated with retrieval strategy of matching. We conclude that lateralized parahippocampal activation may depend on the type of response required.

Altering substrate specificity of Bacillus sp. SAM1606 alpha-glucosidase by comparative site-specific mutagenesis

The Bacillus sp. SAM1606 alpha-glucosidase with a broad substrate specificity is the only known alpha-glucosidase that can hydrolyze alpha,alpha'-trehalose efficiently. The enzyme exhibits a very high sequence similarity to the oligo-1,6-glucosidases (O16G) of Bacillus thermoglucosidasius and Bacillus cereus which cannot act on trehalose. These three enzymes share 80% identical residues within the conserved regions (CR), which have been suggested to be located near or at the active site of the alpha-amylase family enzymes. To identify by site-specific mutagenesis the critical residues that determine the broad substrate specificity of the SAM1606 enzyme we compared the CR sequences of these three glucosidases and selected five targets to be mutagenized in SAM1606 alpha-glucosidase, Met76, Arg81, Ala116, Gly273, and Thr342. These residues have been specifically replaced by in vitro mutagenesis with Asn, Ser, Val, Pro, and Asn, respectively, as in the Bacillus O16G. The 12 mutant enzymes with single and multiple substitutions were expressed and characterized kinetically. The results showed that the 5-fold mutation virtually abolished the affinity of the enzyme for alpha, alpha'-trehalose, whereas the specificity constant for the hydrolysis of isomaltose, a good substrate for both the SAM1606 enzyme and O16G, remained essentially unchanged upon the mutation. This loss in affinity for trehalose was critically governed by a Gly273 --> Pro substitution, whose effect was specifically enhanced by the Thr342 --> Asn substitution in the 5-fold and quadruple mutants. These results provide evidence for the differential roles of the amino acid residues in the CR in determining the substrate specificity of the alpha-glucosidase.

Enhancement of NO production from resident peritoneal macrophages by in vitro gamma-irradiation and its relationship to reactive oxygen intermediates

The functional changes in macrophages (Mphi) following exposure to a high dose (6 Gy) of gamma-rays in vitro were investigated. Resident peritoneal Mphi obtained from C57BL/6 mice were irradiated with gamma-rays (137Cs, 0.3 Gy/min). High-dose irradiation enhanced nitric oxide (NO) production from Mphi treated with interferon-gamma and their cytotoxic activity. The enhancement of NO production by irradiation was attributed to high levels of expression of the inducible nitric oxide synthase. Furthermore, the participation of reactive oxygen intermediates in NO production was examined. Nitric oxide production was not enhanced by treatment with the membrane-oxidizing agent tert-butyl hydroperoxide or the hypoxanthine/xanthine oxidase superoxide (O2.-)-generating system. On the other hand, NO production was enhanced by treatment with a low dose of hydrogen peroxide (H2O2), which can diffuse passively through the cell membrane and can be converted into hydroxyl radicals (HO.) that cause DNA breaks. In addition, treatment with low-dose actinomycin D, which induces DNA strand breaks, enhanced NO production, but hydroxyurea, which stops DNA replication without DNA strand breaks, had no such effect. These findings suggest that DNA strand breaks caused by hydroxyl radicals formed inside the cells by gamma-irradiation, or strand breaks caused directly by radiation, plays an important role in the enhancement of NO production, but peroxidation of cell membranes has little effect.

[Development of a new statistical evaluation method for brain SPECT images]

The purpose of this study was to develop a new statistical evaluation method for Brain SPECT images. First, we made normal brain image databases using 99mTc-ECD and SPECT in 10 normal subjects as described previously. Each SPECT images were globally normalized and anatomically standardized to the standard brain shape using Human Brain Atlas (HBA) of Roland et al. and each subject's X-CT. Then, mean and SD images were calculated voxel by voxel. For the next step, 99mTc-ECD SPECT images of a patient were obtained, and global normalizing and anatomical standardization were performed as the same way. Then, a statistical map was calculated as following voxel by voxel; (P-Mean)/SD x 10 + 50, where P, Mean and SD indicate voxel value of patient, mean and SD images of normal databases, respectively. We found this statistical map was helpful for clinical diagnosis of brain SPECT studies.

Analysis of defense mechanisms against bacterial infection by oral streptococcus in normal flora

The incidence of oral alpha-streptococci with inhibitory activity against pathogens as a defense mechanism in the oral cavity was investigated in healthy individuals. Inhibitory strains were isolated from tonsil, tongue, cheek, saliva and dental plaque, and the detection rate of these strains isolated from tonsil was the highest. These results suggested that tonsillar flora is most important as a defense mechanism of the oral cavity. With respect to the effects of antibiotics against inhibitory alpha-streptococci, minimal inhibitory concentration of 90% of cells (MIC90) of PCG, ABPC, CCL, CFIX and EM against inhibitory alpha-streptococci, and relative detection rates of inhibitory alpha-streptococci before and after antimicrobial therapy were investigated. MIC90s of all antibiotics against these strains were low and sensitive to antibiotics tested. However, in vivo, detection rates of these strains before and after therapy did not differ significantly. Therefore, inhibitory strains were not affected by antibiotics as their MIC90 were low during short term medication.

A simple method for the quantification of benzodiazepine receptors using iodine-123 iomazenil and single-photon emission tomography

Iodine-123 iomazenil (Iomazenil) is a ligand for central type benzodiazepine receptors that is suitable for single-photon emission tomography (SPET). The purpose of this study was to develop a simple method for the quantification of its binding potential (BP). The method is based on a two-compartment model (K1, influx rate constant; k2', efflux rate constant; VT' (=K1/k2'), the total distribution volumes relative to the total arterial tracer concentration), and requires two SPET scans and one blood sampling. For a given input function, the radioactivity ratio of the early to delayed scans can be considered to tabulate as a function of k2', and a table look-up procedure provides the corresponding k2' value, from which K1 and VT' values are then calculated. The arterial input function is obtained by calibration of the standard input function by the single blood sampling. SPET studies were performed on 14 patients with cerebrovascular diseases, dementia or brain tumours (mean age+/-SD, 56.0+/-12.2). None of the patients had any heart, renal or liver disease. A dynamic SPET scan was performed following intravenous bolus injection of Iomazenil. A static SPET scan was performed at 180 min after injection. Frequent blood sampling from the brachial artery was performed on all subjects for determination of the arterial input function. Two-compartment model analysis was validated for calculation of the VT' value of Iomazenil. Good correlations were observed between VT' values calculated by three-compartment model analysis and those calculated by the present method, in which the scan time combinations (early scan/delayed scan) used were 15/180 min, 30/180 min or 45/180 min (all combinations: r=0.92), supporting the validity of this method. The present method is simple and applicable for clinical use.

[Regional distribution of the muscarinic cholinergic receptor in the human brain studied with 11C-benztropine and PET using an anatomical standardization technique]

We measured regional distribution of the muscarinic cholinergic receptor in the normal human brain with 11C-benztropine (BZT) and positron emission tomography (PET) using an anatomical standardization technique. Seven normal volunteers who gave informed consents were involved in this study. Immediately after intravenous injection of 11C-BZT into the subjects, we started dynamic PET scanning and serial frequent arterial blood sampling. Analyses of plasma metabolites were also performed at selected time points and plasma time activity curves (TAC) of unmetabolized ligand were generated. From these PET and TAC data, we obtained Patlak plot slope calculation images. Using the HBA (human brain atlas) system, the Patlak plot slope calculation image of each subject was transformed into the shape of the standard brain. Mean and standard deviation (SD) calculation images were generated from those anatomically standardized images. On these mean and SD images, we placed regions of interest which were previously outlined on a MR image of the standard brain. From those data, we found the highest receptor distribution in the striatum and occipital cortex, as well as high distribution in the frontal, parietal, and temporal cortices, which were consistent with previous reports. These results suggested that anatomical standardization of PET receptor images with 11C-BZT will be useful for delineating the physiological or pathological alterations of the muscarinic cholinergic receptor in the human brain.

The nasopharyngeal bacterial flora in children with otitis media with effusion

A study was undertaken to evaluate the incidence of nasopharyngeal alpha-streptococci with inhibitory activity against pathogens, as a defense mechanism of the normal bacterial flora against infection. Cultures were taken from the nasopharynges of 43 children with otitis media with effusion (OME). The detection rates of alpha-streptococci with inhibitory activity against Haemophilus influenzae, Streptococcus pneumoniae, Staphylococus aureus and group A streptococci were significantly lower in the nasopharynx than those isolated from the tonsils of the same patients. Moreover, the detection rates of alpha-streptococci with inhibitory activity against all of these pathogens derived from the nasopharynx were lower than those in healthy children, streptococcal strains with activity against H. influenzae and Strep, pneumoniae were also lower than that in patients with tonsillitis. These findings suggest that low nasopharyngeal levels of alpha-streptococci with inhibitory activity against respiratory pathogens may render children susceptible to OME. Further studies are needed to investigate the relationships between the prevalence of pathogens in the nasopharynx and the inhibitory activities of alpha-streptococci against them in order to devise and select optimal treatment for patients with OME.

Investigation of the nasopharyngeal bacterial flora in children with otitis media with effusion

A study was undertaken to evaluate the incidence of alpha-streptococci with inhibitory activity against pathogens, a defense mechanism of the normal flora against bacterial infection, in the nasopharynx and tonsils of 37 children with otitis media with effusion (OME). In the patients with OME, the detection rates of alpha-streptococci with inhibitory activity against Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus and group A streptococci in the nasopharynx were significantly lower than those of alpha-streptococci isolated from the tonsils. Furthermore, the detection rates of nasopharyngeal alpha-streptococci with inhibitory activity against H. influenzae and S. pneumoniae in OME patients were lower than those in patients with tonsillitis. In conclusion, low nasopharyngeal levels of alpha-streptococci with inhibitory activity against pathogens appear to render children susceptible to attacks of OME. We suggest that it is important to investigate the relationships between the prevalence of pathogens and the inhibitory activity of alpha-streptococci against them in the nasopharynx.

Hypoperfusion in the limbic system and prefrontal cortex in depression: SPECT with anatomic standardization technique

Depression is a common psychiatric illness, and several reports have described cerebral blood flow (CBF) abnormalities on SPECT studies in affected patients. However, because region of interest analyses were used to determine significant CBF changes in these studies, there were methodological limitations. Therefore, we investigated CBF distribution abnormalities in depression on a pixel-by-pixel basis using SPECT and an anatomic standardization technique that has been commonly used for PET activation studies.

METHODS

Eleven patients with unipolar depression, six patients with bipolar depression and nine age-matched normal control subjects underwent HMPAO brain SPECT studies. The radioactivities of SPECT images for each subject were globally normalized to 100 counts/pixel. Then, each SPECT image was transformed for standard brain anatomy using a computerized Human Brain Atlas system. For each group, the mean and variance images were calculated from the standardized anatomic SPECT images, and group comparisons were performed on a pixel-by-pixel basis.

RESULTS

Significant decreases in CBF in the prefrontal cortices, limbic systems and paralimbic areas were observed in both depression groups compared with the normal control group.

CONCLUSION

Decreases in CBF in these regions may be related to impaired attention as well as cognitive and emotional responses, which have been recognized as usual symptoms in depression. The anatomic standardization technique promises to be useful for group comparison analysis of brain SPECT on a pixel-by-pixel basis for individual neurological and psychiatric diseases.

[Normal cerebral perfusion of 99mTc-ECD brain SPECT--evaluation by an anatomical standardization technique]

A single photon emitter labeled tracer, 99mTc-ethyl cysteinate dimer (99mTc-ECD), has now been used for rCBF studies with SPECT. However, normal distribution pattern of this agent in the brain still remains unclear. Therefore, the specific purpose of this study was to investigate the normal distribution pattern of 99mTc-ECD SPECT image. Regional cerebral distribution was measured with SPECT and 984 +/- 17 MBq of 99mTc-ECD in ten normal subjects. During the SPECT measurement, subjects were placed comfortably in a supine position with their eyes closed. Each SPECT image was anatomically standardized using a computerized brain atlas system of Roland et al. (HBA: Human Brain Atlas) and X-CT image. Anatomically standardized SPECT images were globally normalized to 100 count/voxel. Then, the mean and SD images of brain SPECT were calculated voxel-by-voxel basis. The highest radioactivity was found in the medial aspect of the occipital lobe. The results indicate that the normal distribution pattern of 99mTc-ECD in the human brain may be not simply reflect the regional cerebral blood flow.

Effect of leukotriene C4 exposure on ciliated cells of the nasal mucosa

To clarify the effects of leukotriene C4 (LTC4) on human ciliated epithelium, ciliary activity of the ethmoid sinus mucosa was measured photoelectrically in tissue culture. At concentrations ranging from 10(-6)M to 10(-9)M, LTC4 showed minimal effects on the ciliated epithelium during the initial 30 minutes of exposure; thereafter, ciliary inhibition was observed in a concentration- and time-dependent manner. Irrigation of the mucosa with culture medium 15 minutes after exposure prevented the LTC4-induced ciliary inhibition. However, irrigation 60 minutes after exposure failed to inhibit 10(-8)M LTC4-induced ciliary dysfunction and mucosal damage. The LTC4-induced ciliary inhibition was blocked in the presence of FPL-55712 and/or Ly-171883, both leukotriene receptor antagonists. L-serine and sodium tetraborate complex (SBC), a gamma-glutamyl transpeptidase (gamma-GTP) inhibitor, also inhibited the LTC4-induced ciliary inhibition. These findings indicate that LTC4 is converted to LTD4 by gamma-GTP during 60 minutes of exposure, and LTC4 itself has minimal direct effects on the ciliated cells.

Cerebral blood flow measurement with iodine-123-IMP SPECT, calibrated standard input function and venous blood sampling

We previously reported simple methods for measuring cerebral blood flow (CBF) with 123l-labeled N-isopropyl-p-iodoamphetamine (IMP) and SPECT: table look-up method and autoradiography. With these methods, the arterial input function is obtained by calibrating the standard input function using one-point arterial blood sampling 10 min after IMP infusion. In this study, we sought to determine if these approaches can be as successful when used with venous blood sampling.

METHODS

After IMP infusion, simultaneous arterial and venous blood samples were drawn from 30 subjects without heart or lung disease.

RESULTS

The activity ratios of venous whole blood from the cubital vein to arterial blood were 0.75 +/- 0.09, 0.77 +/- 0.10, 0.78 +/- 0.03 and 0.83 +/- 0.11, respectively, at 10, 20, 30 and 50 min after IMP infusion. Venous blood activities were always 20% lower than the artery values over 50 min. When blood was sampled from the dorsal hand vein, however, the respective ratios were 0.92 +/- 0.03, 0.93 +/- 0.05, 0.97 +/- 0.04 and 0.98 +/- 0.08 after 10, 20, 30 and 50 min. Furthermore, when the palm was exposed to heat during the sampling period, blood activity levels increased to 0.92 +/- 0.04, 0.96 +/- 0.04, 0.99 +/- 0.05 and 0.98 +/- 0.03. Thus, venous blood activities were consistent with arterial activity, presumably because of the numerous arteriovenous anastomoses in the palm. Optimal times for venous blood sampling, with and without palm heating, were determined by error analysis to be 15 and 20 min, respectively, after IMP infusion.

CONCLUSION

Venous blood sampling from the dorsal hand can be substituted for arterial blood sampling in IMP-CBF studies.

The effects of leukotrienes C4 and D4 on ciliary activity of human paranasal sinus mucosa in vitro

The effects of leukotrienes C4 and D4 on ciliary activity of human paranasal sinus mucosa were investigated in vitro. Normal mucosa was surgically obtained from human paranasal sinuses and incubated in the form of tissue culture. Ciliated cells were magnified under an inverted microscope, and ciliary activity was photoelectrically measured. LTD4 progressively inhibited ciliary activity, and showed a more potent effect on ciliary activity compared to LTC4. The concentrations of LTC4 and LTD4 in the incubation medium were determined by radioimmunoassay when the mucosa was incubated with 10(-8) M LTC4. The concentration of LTD4 gradually increased and after 90 min reached the maximum of 0.71 x 10(-8) M, while that of LTC4 was reduced to about 10% of its initial concentration within 60 min. These results suggested the possible conversion of LTC4 to LTD4 on the mucosa, and that LTC4 can inhibit ciliary activity by means of LTD4.

Investigation of oral alpha-streptococcus showing inhibitory activity against pathogens in children with tonsillitis

The incidence of oral alpha-streptococcus with inhibitory activity against group A streptococcus, as a defense mechanism against bacterial infection in the oral cavity, was investigated in pediatric individuals with tonsillitis. Infection by group A streptococcus appeared to be common in children, because the detection rate of inhibitory alpha-streptococcus in healthy children as well as pediatric patients with tonsillitis was lower than in adults and elderly patients. In particular, the detection rate of these strains was predominantly low in patients with beta-streptococcus. Among pediatric patients scheduled for tonsillectomy, the detection rate of inhibitory alpha-streptococcus was low preoperatively. However, the rate was markedly increased after surgery. The high postoperative detection rate of these strains reflected the decreased incidence of group A streptococcal infection. The results of this investigation of bacterial interference between oral alpha-streptococcus and group A streptococcus suggested that surgical treatment is a more effective approach for improving the oral bacterial flora in children with recurrent tonsillitis.

[Participation in causing O.M.E. with nasopharyngeal alpha-Streptococcus]

The role of normal pharyngeal flora in the defense mechanism against infections in the upper respiratory tract was studied in 50 children with otitis media with effusion (O.M.E.). In the bacteriological study of the nasopharynx, the incidence of H. influenzae, S. pneumoniae, S. aureus, M. catarrhalis and group A Streptococcus was about 46%, 24%, 20%, 12% and 8%, respectively. The incidence of these species in the cases with O.M.E. was higher than that in the cases with chronic tonsilitis or control cases. In 41 O.M.E. cases with alpha-streptococci (82%), the incidence of alpha-streptococci with inhibitory activity against 5 pathogens (H. influenzae, S. pneumoniae, S. aureus, M. catarrhalis, group A Streptococcus) was examined. The detection rate of alpha-streptococcal strains with inhibitory activity against 5 pathogens derived from the nasopharynx in the cases with O.M.E. was significantly lower than that of the strain in the chronic tonsilitis cases and the control cases. Moreover, the detection rate of inhibitory alpha-streptococci from the nasopharynx was lower than that of from the tonsil. These findings suggest that the decline of inhibitory activity against pathogens by normal flora in nasopharynx is one of the factors causing O.M.E.

[Normal cerebral perfusion of 99mTc-HMPAO brain SPECT--evaluation by ananatomical standardization technique]

Single photon labeled tracer 99mTc-hexamethylpropylene amine oxime (HMPAO) has been used for rCBF studies by SPECT. However, normal perfusion pattern of this agent still remains unclear. The purpose of this study was to investigate normal 99mTc-HMPAO SPECT image voxel by voxel. Eighteen male subjects without any prior or present history of medical illness participated in this study. All SPECT images were globally normalized to 100 count/voxel. Each subject had an X-ray CT scan at the same day of SPECT measurement. All subjects had normal X-ray CT scans. The standard anatomical structures of the computerized brain atlas of Roland et al. were fitted to X-ray CT images of a subject by linear and non-linear parameters. These parameters were subsequently used to transform SPECT images of the subject. After the anatomical standardization, mean and SD images of eight standardized images were calculated voxel-by-voxel basis. In the mean image, following structures showed relatively higher radioactivity; the putamen, the cerebellum, and the frontal lobe. In addition, the occipital lobe, parietal lobe, frontal lobe, and the putamen showed large degree of SD. Anatomical standardization of SPECT images may be useful as a reference to diagnose and evaluate various brain disorders.

Augmentation of NO production and cytolytic activity of M phi obtained from mice irradiated with a low dose of gamma-rays

The activation of macrophages (M phi) by low-dose irradiation (4cGy) was examined. The irradiated M phi were obtained from mice exposed to a low dose of gamma-rays. The addition of excess irradiated M phi suppressed more the concanavalin A-induced proliferation of splenocytes than that of unirradiated M phi. This was attributed to large nitric oxide (NO) production from irradiated M phi. In addition, low-dose irradiation augmented NO production and glucose consumption in M phi treated with interferon-gamma alone or interferon-gamma/lipopolysaccharide. Furthermore, low-dose-irradiated M phi showed a higher cytolytic activity against P-815 mastocytoma cells than unirradiated M phi, indicating that the NO production was involved in the activity. On the other hand, the M phi irradiated with a low dose in vitro did not enhance the NO production. These findings suggest that whole-body irradiation with a low dose of gamma-rays activates M phi indirectly and consequently enhances NO production from M phi, by which the self-defense systems such as the tumoricidal activity will be augmented.

[A new 3-dimensional head fixation device for brain imaging]

We have developed a new head fixation device for studies of brain function. This device was designed to immobilize subject's heads during image scanning and to precisely reproduce the head position for two different imaging modalities such as MRI and PET. The device consists of a plastic frame, a pillow filled with beads of styrene foam, and a face mask of thermoplastic resin which was originally intended for application in radiotherapy. A bridge for biting was incorporated into the mask for stable fixation. The device enables immobilization of subject's heads with good reproducibility of position at the practical level. Our results indicate that this head fixation system is useful for fixation of head during activation studies using PET.

[Isolation of alpha-streptococci with inhibitory activity against pathogens, in the oral cavity and the effect of tobacco and gargling on oral flora]

We investigated the distribution of oral alpha-streptococci with inhibitory activity against pathogens, which compose an oral defense mechanism. Detection rate of alpha-streptococci with inhibitory activity against S. pyogenes and S. aureus derived from the tonsil was higher than in other portions, the tongue, cheek, gingiva, or saliva. It has suggested that tonsillar bacterial flora are mainly a defense mechanism. The oral flora in healthy smokers was compared with healthy non-smokers to investigate the influence of tobacco on oral bacterial flora. The results showed that the detection rate of S. aureus in smokers was higher while that of alpha-streptococci with inhibitory activity against S. aureus was lower. However, the detection rate of alpha-streptococci with inhibitory activity against S. pyogenes in smokers was as high as in non-smokers. It is suggested that it was easy for S. aureus to adhere to the oral mucosa in smokers, and was considered to influence the strain which produces beta-lactamase for medical treatment. We investigated the influence of gargling on oral bacterial flora by comparing the amount of bacteria before and after gargling with popidine-iodine gargle and saline solution. It was shown that alpha-streptococci, a main component of normal oral flora were decreased after gargling in both smokers and non-smokers. Furthermore, it was shown that group A Streptococcus was not decreased after gargling, and it was concluded that use of gargle medicinal mouth wash in bacillus carriers should be studied further.

Detection of specific IgE antibodies to Japanese cypress pollen in patients with nasal allergy: a comparative study with Japanese cedar

Japanese cypress pollinosis has recently attracted attention and its clinical relationship with Japanese cedar pollinosis has been pointed out. To compare the two kinds of pollinosis, we retrospectively examined specific IgE antibodies to both pollen of Japanese cypress and cedar in the sera of 150 patients with nasal allergy using AlaSTAT assay. During the season in which the pollens of these two species are dispersed, the positive rates for Japanese cypress and cedar increased to 51.4 and 75.0%, respectively. The percentage of patients positive for both of cypress and cedar was elevated to 51.4%, corresponding to 68.5% of the total patient group positive for cedar. Almost all the cases positive for cypress had IgE antibodies to cedar, the value of which was considerably higher than that of cases positive only for cedar. Furthermore, increases in titers of specific IgE antibodies to cypress was observed in four of six cases, compared between specific IgE antibodies to cypress in pre- and post-dispersion of cypress pollen. These findings suggest the following possibility: (i) there is cross-antigenicity between the two pollen species, and (ii) patients are immunologically affected by cypress pollen to express higher levels of specific IgE antibodies after pollen dispersion.

Eosinophil cationic protein in perennial allergic rhinitis

For a quantitative investigation of eosinophil activation in perennial allergic rhinitis, eosinophil cationic protein (ECP) concentrations were measured by a radioimmunoassay in serum, nasal secretions (ECPWN) and in the supernatant of these nasal secretions (ECPsup) obtained from normal subjects and allergic patients. Levels of ECPWN and ECPsup were higher than that of ECPserum. ECPsup showed a positive correlation with clinical severity, despite the lack of a significant correlation with eosinophilia in nasal smears. ECPWN and ECPserum showed no significant correlation with any of these clinical parameters. There was a weak tendency toward an increase in histamine sensitivity of the nasal mucosa of allergic patients with higher ECPsup although this was not statistically significant. These results suggest accumulation and activation of eosinophils in the allergic nasal mucosa, and also indicate that ECPsup may be a clinical parameter of perennial allergic rhinitis.

[A case of hepatocellular carcinoma with lumbar bone metastasis with high uptake of 18F-fluorodeoxygalactose in PET]

18F-fluorodeoxygalactose (18FDGal) is a tracer for the evaluation of galactose metabolism in the tissue. PET with 18FDGal was performed in a hepatoma (HCC) patient with lumbar bone metastasis. The image at 45 min after i.v. injection of 18FDGal demonstrated very high uptake by the bone metastasis with tumor-to-surrounding normal tissue ratio of 36. The tumor uptake expressed by differential absorption ratio was much higher than that in the cirrhotic liver and kidney. The result indicated that the HCC maintained high activity of galactose metabolism and rises the potential of this tracer for detecting extrahepatic metastases of HCC using PET.