The carboxyphosphonoenolpyruvate synthase-encoding gene from the bialaphos-producing organism Streptomyces hygroscopicus

The nucleotide (nt) sequence of the Streptomyces hygroscopicus gene encoding carboxyphosphonoenolpyruvate (CPEP) synthase, that catalyzes a transesterification between phosphoenolpyruvate (PEP) and phosphonoformate (PF) in the bialaphos biosynthetic pathway, has been determined. The amino-acid sequence deduced from the nt sequence is similar to several eukaryotic 2-phospho-D-glycerate hydrolases (EC 4.2.1.11).

Postgastrectomy osteomalacia with pseudofractures assessed by repeated bone scintigraphy

A patient with osteomalacia secondary to vitamin D deficiency after gastrectomy for gastric cancer is presented. Initial bone scintigrams showed both asymmetric and symmetric focal areas of intense uptake due to pseudofractures reminiscent of bone metastases. Radiographs only confirmed the presence of pseudofractures at some, but not all, of the abnormal sites demonstrated by bone scintigraphy. At first, metastatic bone disease was suspected. However, the appearance of repeated bone scintigram was normalized after treatment with vitamin D. A diagnosis of osteomalacia was established. The present case serves to illustrate that symmetric focal lesions are important features of pseudofractures secondary to osteomalacia, and comparison with radiographs and repeated bone scintigraphy are necessary in distinguishing between bone metastases and pseudofractures.

[Assessment of tumor viability by 201Tl SPECT in VX-2 tumor-bearing rabbits after irradiation: comparison with X-ray CT and pathohistologic findings]

In order to evaluate 201Tl SPECT for the assessment of tumor viability after radiation therapy. Twenty rabbits were implanted with VX-2 tumor in the left femoral muscles and were classified into four groups as follows: normal control group (N), 20 Gy irradiated response group (A), 20 Gy irradiated non-response group (B), and 40 Gy irradiated group (C). Eight days after implantation, 201Tl SPECT and CT studies were performed to assess the changes in 201Tl uptake and tumor volume at 0, 1, 2, 3, and 4 weeks after single irradiation. Histologic specimens were also taken. In group N tumors continued to increase in volume, but 201Tl uptake showed a steady decrease after 2 weeks. In group A tumors continued to increase in volume, but 201Tl uptake showed a transient decrease at 2 weeks, then a steady increase. In group B tumors showed a transient increase in volume at 2 weeks, then a continuous decrease, but 201Tl uptake showed a continuous decrease throughout the study. In group C there was a continuous decrease both in volume and 201Tl uptake with the later more prominent. 201Tl uptake was decreased earlier than tumor volume both in group B and C, at one week that was significant (p < 0.01). 201Tl uptake by tumor reflects the burden of viable tumor on histology; therefore 201Tl SPECT is of great use in assessing the therapeutic effects on tumors.

Effect of ionic and nonionic contrast media on regional distribution of thallium-201 in rabbits

Cardiac output is effectively redistributed to each part of the body by regional changes in vascular resistance. Thallium-201 distribution reflects the fractional distribution of cardiac output and parallels regional blood flow. The side effects of iodinated contrast media in different organs have been well documented in animal experiments and clinical studies. However, no simultaneous assessment of regional blood flow change in each part of the body after the administration of contrast media has been reported. Using a double-dose thallium-201 method, we investigated the effect of contrast media on the regional distribution of thallium-201 in each organ as an estimate of regional blood flow change in rabbits. The distribution of 201T1 and 99mTc-MAA was similar in the heart, spleen, kidneys, and leg muscles in the control animals (r = 0.99). The regional distribution of thallium-201 significantly increased in the heart and leg muscle, but decreased in the liver in the nonionic (Iohexol) and ionic (Iothalamate) contrast medium groups as compared with the control group. There were no significant changes in the kidneys or intestine in these three groups in our study. The intravenous infusion of contrast media in rabbits causes uneven redistribution of regional blood flow in the heart, leg muscle and liver. These changes are more prominent in the ionic contrast medium group.

Brain SPECT with neuro-Behçet disease

A patient with neuro-Behcet disease is described. SPECT using Tc-99m HMPAO was performed to evaluate brain perfusion. The brain SPECT revealed decreased perfusion in the right frontal, parietal, temporal, and occipital lobes. MRI showed high intensity lesions in the white matter in the right periventricular centrum semiovale and frontal region on T2 weighted images. Gray matter abnormalities were evident on brain SPECT, but not on MRI. Brain SPECT using Tc-99m HMPAO may provide useful clinical information on regional cerebral cortical abnormalities associated with neuro-Behcet disease.

Clinical symptoms and regional cerebral blood flow in schizophrenia

This study examined the relationship between clinical symptoms and regional cerebral blood flow (rCBF) in schizophrenic patients using single photon emission computed tomography (SPECT). The subjects were 26 medicated schizophrenic patients diagnosed according to DSM-III-R criteria. Clinical symptoms were assessed using the Scale for the Assessment of Negative Symptoms (SANS), selected items for the Positive and Negative Syndrome Scale (PANSS), and the scale for Schneider's first rank symptoms. Resting rCBF was measured using N-isopropyl-p-[I-123] iodoamphetamine (I-123 IMP) SPECT, and relative rCBF distribution was evaluated in nine regions of interest in each hemisphere. Factor analysis of symptom ratings indicated four separate syndromes: psychomotor poverty, alienation (hallucination and disturbance of the self), delusion, and disorganization. Stepwise multiple regression analysis showed the psychomotor poverty syndrome to be correlated with decreased rCBF in bilateral superior frontal areas and increased rCBF in the left thalamus and right basal ganglia. The disorganization syndrome was correlated with increased rCBF in bilateral anterior cingulates and decreased rCBF in bilateral middle frontal areas. The alienation syndrome was shown related to increased rCBF in the right inferior frontal area and parietal area. Dysfunction in distinctive neural networks involving various prefrontal areas would thus appear to underlie these syndromes in schizophrenia.

Antitumor activity of SPM VIII, a derivative of the nucleoside antibiotic spicamycin, against human tumor xenografts

The antitumor activity of spicamycin analogue SPM VIII against human stomach, breast, lung, colon and esophageal cancers was compared to that of mitomycin C (MMC) in the human tumor-nude mice xenograft model. Comparative studies of SPM VIII given i.v. at 6 mg/kg/day daily for 5 days and MMC given i.v. at 6.7 mg/kg on day 1 revealed that the antitumor spectrum of SPM VIII showed a different pattern from that of MMC and that SPM VIII caused tumor mass reductions in more tumors than did MMC in colon cancers (4/12 versus 1/11). In addition to this study, a comparative study of SPM VIII given i.v. at 12 mg/kg/day 8 times at 3- or 4-day intervals and 5'-deoxy-5-fluorouridine (5'-DFUR) given po at 185 mg/kg/day 5 days per week for 4 weeks showed that SPM VIII had the highest effect on SC-9 human stomach cancer and COL-1 human colon cancer among the 3 compounds, resulting in a significant reduction of tumor mass. Although other pharmacological studies are in progress, these results suggest that SPM VIII might be a novel antitumor compound effective for human cancers including cancer of the digestive organs.

Cororubicin, a new anthracycline antibiotic generating active oxygen in tumor cells

In the course of our screening for antitumor antibiotics which show biological activities by generating active oxygen in tumor cells. Micromonospora sp. JY16 was found to produce a new anthracycline antibiotic designated cororubicin. The structure of cororubicin was elucidated as shown in Fig. 5 on the basis of NMR spectral analysis. Cororubicin generated superoxide radicals in tumor cells and showed cytotoxicity, which was reduced by addition of an antioxidative agent, dithiothreitol (DTT).

Assessment of residual tumor viability in thymic carcinoma by sequential thallium-201 SPECT: comparison with CT and biopsy findings

We present a case of 201TI accumulating thymic carcinoma, in which sequential CT scans demonstrated a steady decrease in tumor volume. The presence of a residual mass on CT scans after the completion of therapy presented the clinical dilemma of whether or not a viable tumor remained. Sequential 201TI SPECT images demonstrated a marked decrease in tumor uptake. At 2 wk after therapy, no significant accumulation of 201TI in the region of the residual mass was observed, indicating a lack of viable tumor. A biopsy specimen revealed no tumor cells. Sequential histopathologic findings were correlated well with the findings of 201TI SPECT rather than those of CT. Thallium-201 SPECT is of great clinical value in assessing tumor viability in the course of therapy.

Microbial metabolites with tipA promoter inducing activity. II. Geninthiocin, a novel thiopeptide produced by Streptomyces sp. DD84

Geninthiocin was isolated from the mycelium of Streptomyces sp. DD84 as a tipA promoter inducing substance. Based on various NMR studies, its structure was established as a thiopeptide with oxazole and thiazole moieties, and several unusual amino acids.

Expression of PDGF, PDGF-receptor, EGF-receptor and sex hormone receptors on meningioma

The expression of platelet derived growth factors (PDGF), the PDGF-Receptor (R) (alpha and beta types), epidermal growth factor (EGF)-Receptor (R) and sex hormone (oestrogen and progesterone) receptors was studied in 22 meningiomas. All tumours were PDGF-R beta type positive and 21 (95%) were PDGF positive. Only 2 (9%) were PDGF-R alpha type positive, 13 (59%) were EGF-R positive. The expression of these proteins was not related to the histological type or the malignancy of the meningiomas although the expression of PDGF and PDGF-R beta tended to be stronger in malignant meningiomas. Oestrogen and progesterone receptor protein were examined in 19 patients (10 females and 9 males). None of the meningioma cells revealed oestrogen receptor protein while 17 (89%) of the 19 meningiomas were positive for progesterone receptor protein. The expression of progesterone receptor was not related to histological type or malignancy. Our studies suggest that the autocrine system, through PDGF and PDGF-R type beta, may play an important role in the tumourigenicity of meningiomas. EGF-R was present in almost half and progesterone receptor in most of the meningiomas. There was no correlation between the expression of either PDGF, PDGF-R or EGF-R and the expression of progesterone receptor protein.

Thallium-201 single photon emission computed tomography in the evaluation of thymic carcinoma

Thymic carcinoma is a rare mediastinal tumor that is distinguished from malignant thymoma without cytologic atypia. We present two cases of thymic carcinoma with high uptake of Tl-201. Absence of Tl-201 uptake in a residual mass on the CT scan indicated a lack of tumor viability after the completion of therapy, which was verified by sequential needle biopsy. Tl-201 SPECT seems to be useful both in detecting thymic carcinoma and in assessing the therapeutic effect.

Assessment of congenital left ventricular diverticulum by magnetic resonance imaging: comparison with myocardial perfusion

We report two cases of left ventricular diverticulum assessed by magnetic resonance (MR) and radionuclide imaging. MR imaging clearly demonstrated the diverticulum in each case, where abnormal perfusion was observed on Tl-201 myocardial SPECT.

Clinical utility of three-dimensional time-of-flight magnetic resonance angiography for the evaluation of intracranial aneurysms

Magnetic resonance (MR) angiographic studies of 14 patients with intracranial aneurysms (AN) were analyzed retrospectively as compared with contrast angiographic studies. Eighteen of 19 (95%) lesions were detected, and the relation between AN and their parent vessels was precisely assessed. The diameter of the smallest aneurysm detected in our case was 3 mm. However, small vessels around AN were not visualized. Therefore, MR angiography (MRA) is definitely not a substitute for preoperative contrast angiography. MRA is a useful screening tool for nonruptured AN, but further refinement is required to evaluate emergency ruptured AN.

Basilar artery migraine. Reversible ischemia demonstrated by Tc-99m HMPAO brain SPECT

The authors present a case of basilar artery migraine in a 33-year-old woman who was initially misdiagnosed as having a cerebrovascular or mental disorder and subjected to MRI and cerebral angiography, which, however, did not show any pathologic findings. During admission to the university hospital, she lost consciousness. An emergency Tc-99m HMPAO brain SPECT showed a significant decrease of regional cerebral blood flow in the right temporal and occipital cortices, and right cerebellar hemisphere, where regional cerebral blood flow was decreased by 10-24% as compared to the left side. The second brain SPECT during a symptom-free phase showed the reversion of regional cerebral blood flow to normal in these areas. Basilar artery migraine was diagnosed by the finding of reversible ischemia in the territory of the right basilar artery on brain SPECT images and the clinical picture.

Primary splenic lymphoma presenting as a large cyst

An atypical case of splenic lymphoma is presented. A large cystic mass lesion in the splenic area was found in an 80-year-old man. He was involved in a traffic accident, and subsequently the cyst ruptured. The histological diagnosis of malignant lymphoma was made at emergency splenectomy. No other lesions were identified, and there were no signs of tumor recurrence four months after the operation.

Neurotoxicity and pharmacokinetics of ventriculolumbar perfusion of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU) in dogs

Ventriculolumbar perfusion of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU), a water soluble nitrosourea with log P -0.71, may be efficacious in the treatment of subarachnoid dissemination of malignant glioma. We used 2 dogs to study the neurotoxicity and pharmacokinetics of MCNU. MCNU (1 mg), dissolved in 10 ml of artificial CSF, was administered via the right lateral ventricle during a period of 18 to 42 min and the CSF was drained by lumbar puncture. The perfusion was repeated once a week for 10 consecutive weeks. No neurological and systemic symptoms were noted after perfusion. Histological examination of the brain and spinal cord showed local denudation of the ependyma and local subependymal spongy degeneration and gliosis in the lateral ventricle into which MCNU was administered in one dog and local denudation of the ependyma in the other. When administration was over a period of 21 to 38 min, the MCNU concentration in the lumbar CSF peaked at 11.11 to 50.67 micrograms/ml, in 28 to 78 min. The area under the drug concentration-time curve (AUC) was 1152 micrograms x min/ml on average, significantly larger than that of ACNU. The elimination phase followed linear kinetics and the half-time was 41.1 min on average, significantly longer than that of ACNU. These findings suggest that ventriculolumbar perfusion of MCNU may be effective in the treatment of subarachnoid dissemination of malignant glioma notwithstanding some local histological changes.

Diffuse increased renal uptake on bone scintigraphy in acute tubular necrosis

Acute renal failure after exercise with frank pain and patchy renal vasoconstriction is a clinical syndrome that occurs in young, previously healthy persons. The authors describe a 24-year-old man who had this syndrome. CT scan showed wedge-shaped contrast enhancement of both kidneys, which suggested patchy renal vasoconstriction. Tc-99m MDP imaging revealed diffuse increased uptake of both kidneys. After renal function was improved, Tc-99m MDP imaging showed normal uptake of both kidneys. Acute renal failure due to acute tubular necrosis was confirmed by renal biopsy. The authors conclude that Tc-99m MDP may be useful in evaluation of acute renal failure after exercise with flank pain and patchy renal vasoconstriction due to acute tubular necrosis.