The limitations of gallium scintigraphy in the differentiation between benign and malignant salivary gland mass lesions

The aim of this study was to evaluate the ability of gallium scintigraphy to differentiate between benign and malignant salivary gland mass lesions and to identify what types of lesions surpass its diagnostic utility. By considering the uptake of 67Ga, 193 salivary gland masses were graded visually as negative, weakly positive, moderately positive or strongly positive in comparison to the uptake in the nasal cavity and the liver. The uptake was compared with histopathological findings. Among 39 malignant tumours, uptake was positive in 31 (79%) (strongly positive in 18, moderately positive in seven and weakly positive in six) and uptake was negative in eight (21%). Adenoid cystic carcinoma was the most common malignant tumour in our study (11/39), and uptake was negative in five (45%) of these tumours. Malignant tumours did not differ significantly in size despite differences in uptake. Among 154 benign lesions, uptake was negative in 101 (66%) and positive in 53 (34%) (strongly positive in 12, moderately positive in 19 and weakly positive in 22). Out of 88 pleomorphic adenomas, 41 (47%) showed positive uptake. Sensitivity, specificity and accuracy for gallium study were 80%, 66% and 68%, respectively, when the malignancy criterion was weakly positive uptake. Accuracy was greatest (83%) when the criterion was strongly positive uptake, but this criterion failed to detect more than a half of malignant tumours (46% sensitivity). In conclusion, gallium scintigraphy had limitations in differentiating between benign and malignant salivary gland mass lesions. Adenoid cystic carcinomas and pleomorphic adenomas were the principal sources of false negative and false positive results, respectively.

Technetium-99m-ECD SPECT in antiphospholipid antibody syndrome: a drastic improvement in brain perfusion by antiplatelet therapy

We present a case of antiphospholipid antibody syndrome (APS) with repeated transient ischemic attacks (TIAs). Magnetic resonance imaging showed multiple cerebral infarcts and ischemic changes in the cerebral white matter. Cerebral angiographies showed no abnormalities. Technetium-99m-ethyl cysteinate dimer (Tc-99m-ECD) brain SPECT showed multiple decreased perfusion areas, which were more extensive than the lesions demonstrated on MRI. After treatment with an antiplatelet agent, the patient subsequently recovered from the TIAs. Although no interval changes were observed by MRI after therapy, follow-up Tc-99m-ECD SPECT revealed a marked improvement in brain perfusion. This is the first imaging report of remarkable post-therapy improvement in brain perfusion in APS cases.

123I-IMP SPET in the diagnosis of primary central nervous system lymphoma

We reviewed N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) single-photon emission tomography (SPET) images of brain tumours and assessed the usefulness of 123I-IMP SPET for the diagnosis of primary central nervous system (CNS) lymphoma. We analysed 52 tumours that showed enhancement on magnetic resonance imaging: 11 malignant lymphomas, 3 anaplastic astrocytomas, 17 glioblastomas, 12 meningiomas, 4 metastatic brain tumours and 5 other brain tumours. 123I-IMP uptake in the tumours on early (15-min) and delayed (4-h) scans was visually classified as high, moderate or low as compared with the contralateral brain cortex. Early and delayed 123I-IMP uptake ratios comparing tumours with contralateral brain cortex (T/N ratio) were also calculated. In malignant lymphomas, the visual uptake of 123I-IMP was moderate to high on the delayed scans. The delayed T/N ratios were significantly higher than the early ratios (P<0.05) and all lymphomas, with the exception of one small one, had delayed ratios greater than 0.9. In non-lymphomatous tumours, the visual uptake of 123I-IMP was low on the delayed scans. The delayed T/N ratios were significantly lower than the early ratios (P<0.01) and all non-lymphomatous tumours had delayed ratios of less than 0.8. The T/N ratios of lymphomas were significantly higher than those of non-lymphomatous tumours on both early and delayed scans (P<0.0001). These results suggest that 123I-IMP SPET may be a useful tool in the differential diagnosis of primary CNS lymphoma.

Posterior lenticonus with congenital cataract in a Shih Tzu dog

A seven-month-old, male Shih Tzu dog weighing 3.7 kg had an immature cataract in its left eye. A biomicroscopic examination revealed numerous vacuolations in the posterior cortices with nucleus cataracts, covered by an intact anterior lens capsule. The changes observed by ocular sonographic examination (OSG) of the left eye were hyperechoic, and a funnel-cone shape was observed posteriorly with cortex hyperechogenicity in the lens. The left eye was diagnosed as having a posterior lenticonus with congenital cataract. Phacoemulsification was performed on the left eye as diagnostic treatment of the posterior lenticonus and cataract. Postoperative OSG on the left eye revealed a V-shaped linear echo that was indicative of a posterior capsule of the lens. Moreover, it was confirmed that hyperechoic cataract material inside the lens had disappeared.

Thallium-201 SPECT of adjacent intracranial tumours: a contrast in thallium kinetics

We report a case of adjacent intracranial tumours: malignant fibrous histiocytoma (MFH) and meningioma. Thallium-201 single-photon emission computed tomography demonstrated different thallium kinetics between the tumours (slow washout from the MFH and rapid clearance in the meningioma) and could be said to have been useful for preoperative histological estimation.

Pleomorphic adenoma of the salivary glands: correlation between gallium-67 uptake and histopathological components

We correlated 67Ga uptake and histopathological findings in pleomorphic adenomas of the salivary glands.

METHODS

Sixty-two pleomorphic adenomas of the salivary glands were visually graded by degree of 67Ga uptake as negative, weakly positive or strongly positive in comparison to uptake in the nasal cavity. These adenomas were re-examined pathologically and classified as epithelial, intermediate or mesenchymal type according to their dominant histological components. The pathological presence of marginal invasion or associated sialoadenitis was also re-examined.

RESULTS

Eighteen adenomas were classified as strongly positive, eight as weakly positive and 36 as negative. Nine (50%) of the 18 strongly positive adenomas were of the epithelial type and the other nine (50%) strongly positive adenomas were of the intermediate type. While none of the strongly positive adenomas were of the mesenchymal type, 27 (75%) of the 36 negative adenomas were of the mesenchymal type. Six (75%) of the eight weakly positive adenomas were of the intermediate type. About half of the adenomas showed marginal invasion regardless of the grade of 67Ga uptake. None of the strongly positive adenomas were associated with sialoadenitis.

CONCLUSION

The epithelial component of pleomorphic adenomas may be responsible for 67Ga uptake. The presence of marginal invasion or associated sialoadenitis has little relation to 67Ga uptake in pleomorphic adenomas.

Persistent hyperplastic primary vitreous (PHPV) in two Siberian husky dogs

Three eyes in two Siberian husky dogs were clinically diagnosed as persistent hyperplastic primary vitreous (PHPV) by means of ophthalmoscopy and ultrasonography (USG). Examination of mildly affected PHPV eyes with an ophthalmoscope showed the axial part of the posterior capsule to be opaque. The central lesion of the posterior capsule in severely affected eyes had been opaque with many blood vessels. Echographic changes in mild cases of PHPV were outside of the lens, linearly hyperechoic, parallel to the posterior lens capsule. In a severely affected eyeball, funnel-shaped hyperechoic change was noted in the retrolental space. Two months later, phacoemulsification was performed for diagnostic treatment of PHPV since progressive cataract was observed in this eye.

Plain CT findings of brain death confirmed by hollow skull sign in brain perfusion SPECT

Computed tomographic (CT) findings of 13 patients manifesting brain death were reviewed. This diagnosis was confirmed by the so-called "hollow skull" pattern observed in brain perfusion single photon emission computed tomography (SPECT), which was performed between 4 hours before and 3 days after the CT scans, and by subsequent corporal death. The brain perfusion SPECT was performed with the intravenous administration of technetium (Tc)-99m-hexamethylpropyleneamine oxime (HMPAO) or iodine (I)-123-N-isopropyl-p-iodoamphetamine (IMP). CT scans showed diffuse cerebral edema and the loss of gray-white matter differentiation in all the cases, and transtentorial herniation in 12 patients. These CT findings were considered predictive of brain death.

Comparisons of prolonged sevoflurane, isoflurane, and halothane anaesthesia combined with nitrous oxide in spontaneously breathing cats

The clinical, cardiopulmonary, haematologic, and serum biochemical effects of sevoflurane, isoflurane and halothane anaesthesia with 66% nitrous oxide, were compared in healthy, premedicated cats breathing spontaneously during 6 h of anaesthesia. Recovery time from anaesthesia with sevoflurane-nitrous oxide was more rapid than that with halothane-nitrous oxide, but it does not differ from that with isoflurane-nitrous oxide. The degree of respiratory acidosis with sevoflurane-nitrous oxide anaesthesia was similar to that with isoflurane-nitrous oxide and was less than that with halothane-nitrous oxide. There were no significant differences among the groups in the heart rate, arterial pressures, haematological and serum biochemical values. The three anaesthetic regimens induced a similar degree of hyperglycemia during anaesthesia. Serum biochemical examination did not reveal apparent hepatic or renal injuries after each anaesthesia. Time-related increases in respiration rate and arterial carbon dioxide partial pressure were observed during prolonged halothane-nitrous oxide anaesthesia. No significant time-related changes in cardiopulmonary variables were observed during either sevoflurane- or isoflurane-nitrous oxide anaesthesia. Therefore, sevoflurane-nitrous oxide may be used as an effective and safe anaesthetic combination similar to isoflurane-nitrous oxide for long-term anaesthesia in healthy cats.

Inferior mesenteric varix demonstrated by 99mTc-red blood cell gastrointestinal bleeding study

Reported here is a case of an inferior mesenteric varix demonstrated by 99mTc-red blood cell (RBC) scintigraphy performed for gastrointestinal bleeding in a 47-year-old man. It was shaped like a question mark ranging from the left upper abdomen to the pelvis. This is the first report of scintigraphic recognition of an inferior mesenteric varix.

Assessment of response to cancer therapy using fluorine-18-fluorodeoxyglucose and positron emission tomography

In order to evaluate the usefulness of 18F-FDG PET in the assessment of therapeutic effects, FDG-PET studies were performed both before and after therapy in 26 patients with miscellaneous malignant tumors. The change in FDG uptake by therapy was compared with the change in tumor size and prognosis. All 26 lesions had a high FDG uptake before therapy. Five of seven lesions which had a relatively low FDG uptake before therapy showed no change or increase in tumor size by therapy. The decreased FDG uptake after therapy was more prominent in the partial response group than in the no change group. FDG uptake before therapy in the non-relapse group was higher than that in the relapse group. However, a decreased FDG uptake did not necessarily indicate a good prognosis. One patient with no change in tumor size and a decreased FDG uptake had no recurrence. This suggests that FDG-PET has a complementary role in the assessment of therapeutic effects.

Positive and negative regulation of transcription by a cleavage product of Ada protein

The 39,000 Mr Ada protein of Escherichia coli that carries two distinct methyltransferase activities and activity to promote transcription of the ada and the alkA genes is cleaved by a cellular proteinase. As a result, the 20,000 and the 19,000 Mr proteins are formed, which are derived from the N-terminal and the C-terminal halves of the protein, respectively. To elucidate the molecular mechanism of transcriptional control by Ada protein, the N-terminal 20,000 Mr protein was overproduced by manipulating the cloned ada gene. The protein possessed an activity to transfer a methyl group from the methylphosphotriester of the alkylated DNA to its own molecule and retained the potential to promote transcription of the alkA gene. The methylated form of the 20,000 Mr proteins binds to the proper alkA regulatory sequence, as does the intact Ada protein, and facilitates further binding of RNA polymerase to the promoter, thus forming an active transcription initiation complex. The non-methylated 20,000 Mr protein was incapable of binding itself or supporting RNA polymerase binding to the alkA promoter. When the 20,000 Mr protein was produced under the control of the lac promoter in E. coli and then exposed to a methylating agent, a considerable amount of 3-methyladenine-DNA glycosylase II, the product of the alkA gene, was formed. Thus, the results obtained in in vitro experiments were confirmed by the events observed in vivo. The methylated 20,000 Mr protein also binds to the ada promoter; however, it does not facilitate further binding of RNA polymerase to the promoter nor does it promote ada transcription in vitro. These findings indicate that the N-terminal half of Ada protein is mainly responsible for recognition of and binding to alkA and the ada regulatory sequence. The methylated 20,000 Mr protein occupies the same region of the ada promoter to which the intact Ada protein would bind, thereby suggesting that it acts as a repressor for expression of the ada gene. The ada transcription promoted by the Ada protein was greatly inhibited by the methylated, but not the non-methylated, form of the 20,000 Mr protein. In an in vivo system, formation of the 20,000 Mr protein leads to inhibition of transcription from the ada promoter. We suggest that termination of the adaptive response may come about by proteolytic cleavage of the Ada protein, the result being a loss of the activator as well as formation of the repressor for ada transcription.

Proteolytic cleavage of Ada protein that carries methyltransferase and transcriptional regulator activities

The 39-kDa Ada protein that carries two distinct methyltransferase activities and an activity to promote transcription of the ada and alkA genes is cleaved to smaller polypeptides in the case of incubation with a crude extract of Escherichia coli. A protease that specifically cleaves the Ada protein was partially purified and characterized. The enzyme showed maximal activity at pH 7.8-8.0 and did not require specific ions or ATP for the reaction. The activity was inhibited by p-chloromercuribenzoic acid, thereby suggesting that it is a thiol protease. When a purified preparation of Ada protein was incubated with the protease preparation, definite sizes of cleavage products were formed; at the initial stage of proteolysis, the 20- and 19-kDa proteins were formed as the major products. When each of these products was purified by successive column chromatography, the 20-kDa protein was found to catalyze transfer of a methyl group from methylphosphotriester of methylated polynucleotides, whereas the 19-kDa protein transfers a methyl group from O6-methylguanine of methylated DNA to each of the molecules. Neither the 20- nor 19-kDa protein, even after methyl acceptance, exhibited an activity to promote transcription of the ada gene. However, alkA transcription was promoted by the 20-kDa protein provided that it was methylated.

[A follicular, medium-sized cell lymphoma showing minimal progress in the last 13 years--case report]

A case history of a 39-year-old woman with a follicular, medium-size cell type lymphoma (Nodular poorly differentiated lymphocytic lymphoma) is reported. In spite of receiving no treatment, her lymphoma had changed little for 13 years. This case is regarded as a good example for considering the treatment of low grade malignant lymphomas.

Hemosuccus pancreaticus: CT manifestations

A case of severe gastrointestinal bleeding due to rupture of a splenic artery aneurysm into the pancreatic duct (hemosuccus pancreaticus) was encountered. Contrast enhanced CT revealed a low-density mass containing an enhancing central area in the pancreatic tail. Arteriography demonstrated a splenic artery aneurysm. Postoperative pathological review revealed a communication between the ruptured splenic artery aneurysm and the pancreatic duct.

Intrarectal hyperthermia of circumferential rectal cancer. Report of 2 cases

An intrarectal microwave (2,450 MHz) applicator was designed for hyperthermia of rectal cancer. Combined treatment of hyperthermia and irradiation was applied in two selected cases. The lesions of case 1 regressed completely, but cancer cells were still present after treatment in case 2. Such hyperthermia is useful for other circumferential cancers such as those of the esophagus and biliary tract. Combined hyperthermia and irradiation are an effective means of achieving therapeutic gains.