Clinical presentations and results of therapy of 63 acromegalic patients Chang Gung Memorial Hospital

Retrospective analysis of 63 acromegalic patients who received regular follow-up in Chang Gung Memorial Hospital is presented. Our purpose was to examine clinical characteristics of acromegalic patients and the results of combination therapy in this medical center. Fifty-one cases received operative treatment. Among them, 43 cases presented with extrasella involvement of the pituitary tumor. Postoperative external radiotherapy was performed in 20 cases. Thirteen cases received medical treatment with bromocriptine or octreotide. After surgery, growth hormone (GH) levels in 23 out of 51 cases (45.1%) were reduced to less than 5 ng/mL. In cases which received postoperative radiotherapy, mean GH level could be reduced gradually after the treatment. In the group treated with bromocriptine, the GH level was controlled in three of nine patients. In five of the six cases who received octreotide therapy. GH levels were maintained at less than 5 ng/mL. Although GH levels were reduced after octreotide treatment, the paradoxical response to the thyrotropin-releasing hormone (TRH) stimulation test still persisted. The data presented in this study suggest that after combination therapy for acromegalic patients (most cases with pituitary macroadenoma), the serum GH levels in 90% cases could be maintained at less than 5 ng/mL.

5-Fluoro-2-pyrimidinone, a liver aldehyde oxidase-activated prodrug of 5-fluorouracil

5-Fluorouracil (5-FU) is an effective antitumor agent used in treating various cancers. Because of its metabolism by intestinal and other cells, 5-FU has an inconsistent bioavailability that limits its oral use. 5-Fluoro-2-pyrimidione (5-FP), a 5-FU prodrug, was synthesized and found to be converted to 5-FU by aldehyde oxidase, an enzyme present in high concentrations in the livers of mice and humans but not in the gastrointestinal tract. Using BDF1 mice, the pharmacokinetics of 5-FP were studied and compared with those of 5-FU. The bioavailability of 5-FP given orally was 100% at a dosage of 25 mg/kg and 78% at a dosage of 50 mg/kg. The half-lives of both doses of 5-FP were at least 2-fold longer than the half-lives of the same doses of 5-FU, and the clearance rates of 5-FP were 3-fold slower. 5-FP was converted rapidly to 5-FU, in vivo. The resulting 5-FU was measured at a steady-state level of 40-70 microM in plasma, at a dosage of 25 mg/kg, that was sustained for at least 4 hr. Also, when given orally, 5-FP was shown to have potent activity against Colon 38 tumor cells and P388 leukemia cells in mice. The therapeutic index of 5-FP was similar to that of 5-FU in these mouse tumor models. The potential clinical use of 5-FP as a prodrug of 5-FU should be considered.

Combination chemotherapy with carmustine and cisplatin before, during, and after radiotherapy for adult malignant gliomas

Twenty-two patients, aged 16 to 67, who had malignant gliomas after surgical resection were treated with carmustine and cisplatin intravenous infusion before, during, and after radiotherapy. All patients had subtotal or total resection, or biopsy as the initial procedure. Twenty-one patients who had at least 2 cycles of chemotherapy and finished the whole course of radiotherapy were considered to be evaluable for responses. Among them, 5 had glioblastoma multiforme, 16 had anaplastic astrocytoma. The median time to tumor progression was 35 weeks (range 12-130 weeks) and median survival time was 66 weeks (range 10-156 weeks). Early progression occurred more frequently in patients with biopsy only and subtotal resection, and in patients with glioblastoma than in those with anaplastic astrocytoma. This combined modality treatment program was associated with reversible hematologic toxicity which was severe in 2 patients, and with ototoxicity in 1 patient, nephrotoxicity in 2 patients. Combination of carmustine and cisplatin with cranial irradiation for malignant gliomas is moderately toxic and appears to offer no obvious survival advantage compared with radiation therapy plus BCNU alone.

Semi-automatic tracking of myocardial motion in MR tagged images

Tissue tagging using magnetic resonance (MR) imaging has enabled quantitative noninvasive analysis of motion and deformation in vivo. One method for MR tissue tagging is Spatial Modulation of Magnetization (SPAMM). Manual detection and tracking of tissue tags by visual inspection remains a time-consuming and tedious process. The authors have developed an interactively guided semi-automated method of detecting and tracking tag intersections in cardiac MR images. A template matching approach combined with a novel adaptation of active contour modeling permits rapid analysis of MR images. The authors have validated their technique using MR SPAMM images of a silicone gel phantom with controlled deformations. Average discrepancy between theoretically predicted and semi-automatically selected tag intersections was 0.30 mm+/-0.17 [mean+/-SD, NS (P<0.05)]. Cardiac SPAMM images of normal volunteers and diseased patients also have been evaluated using the authors' technique.

Maxillary involvement in central craniofacial fractures with associated head injuries

From January 1983 through December 1990, we treated 703 patients with central craniofacial fractures. Among them 177 had maxillary fractures, with or without frontonasoethmoidal involvement. Of the 177, 151 patients were diagnosed in the acute stage. Using the Glasgow Coma Scale, these 151 patients were divided into three groups: group I (GCS score 13-15), 100 patients; group II (GCS score 9-12), 33 patients; group III (GCS score 3-8), 18 patients. The patterns of facial fractures were analyzed and surgically corrected after the following average postadmission lags: group I, 7.1 days; group II, 11.5 days; group III, 13.3 days. The average hospital stay for each group was: group I, 15.6 days; group II, 19.5 days; and group III, 27.2 days. The mean follow-up period was 12 months. The physiologic, functional and esthetic outcomes were assessed. Regardless of initial head injury severity, the outcomes in each group showed almost no statistically significant differences, and unnecessary extended hospital stays may be avoided by early surgical management.

An intracranial aneurysm associated with a recurrent meningioma--a case report

A patient presented with late onset seizure due to sphenoid ridge meningioma excision, during a craniotomy. Nine years after craniotomy, sphenoid ridge meningioma recurred in this patient along with middle cerebral artery (MCA) aneurysm. Peripheral intracranial aneurysm has been shown to be caused by many etiologies. But a direct relationship to an intracranial neoplasm is extremely rare. A causal relationship between the growth of the tumor and the development of the aneurysm is postulated.

Chylothorax after endoscopic sympathectomy: case report

Endoscopic sympathectomy is a new trend for the treatment of hyperhidrosis palmaris. It is a simple and effective technique; however, it carries some recognized risks such as Horner's syndrome and pneumohemothorax. We recently encountered a case complicated by the development of a chylothorax. The patient was a 23-year-old healthy women with profuse palmar sweating. She developed an intractable dry cough after a transthoracic endoscopic sympathectomy. A chest x-ray revealed a left pleural effusion. A chylous effusion was found after thoracentesis and fluid analysis. The pleural effusion resolved after chest tube drainage and diet control. Although endoscopic sympathectomy is a simple and quick procedure, unusual complications, such as chylothorax, may occur. Appropriate early recognition and treatment can prevent a disastrous result.

Characterization of a hydroxyurea-resistant human KB cell line with supersensitivity to 6-thioguanine

Hydroxyurea (HU) is currently used in the clinic for the treatment of chronic myelogenous leukemia, head and neck carcinoma, and sarcoma. One of its drawbacks, however, is the development of HU resistance. To study this problem, we developed a HU-resistant human KB cell line which exhibits a 15-fold resistance to HU. The characterization of this HU-resistant phenotype revealed a gene amplification of the M2 subunit of ribonucleotide reductase (RR), increased levels of M2 mRNA and protein, and a 3-fold increase of RR activity. This HU-resistant cell line also expressed a "collateral sensitivity" to 6-thioguanine (6-TG), with a 10-fold decrease in the dose inhibiting cell growth by 50% as compared to the KB parental line. The mechanism responsible for this supersensitivity to 6-TG is believed to be related to an increasingly efficient conversion of 6-TG to its triphosphate form, which is subsequently incorporated into DNA. After passage of the resistant cells in the absence of HU, the cell line reverts. The revertant cells lose their resistance to HU and concomitantly their sensitivity to 6-TG. This phenomenon is due to the return of RR to levels comparable to that of the KB parental cell line. These observations and their relevance to cancer chemotherapy will be discussed in this paper. Our results suggest that a clinical protocol could be designed which would allow for a lower dose of 6-TG to be used by taking advantage of the increased RR activity in HU-refractory cancer patients. Two drugs which display collateral sensitivity are known as a "Ying-Yang" pair. Alternate treatment with two different Ying-Yang pairs is the rationale for the "Ying-Yang Ping-Pong" theory in cancer treatment. This rationale allows for effective cancer chemotherapy with reduced toxicity.

Anti-Tac(Fab)-PE40, a recombinant double-chain immunotoxin which kills interleukin-2-receptor-bearing cells and induces complete remission in an in vivo tumor model

We have produced a single plasmid encoding both the heavy chain Fd domain (VH + CH1) of the anti-interleukin-2 receptor (IL2R) monoclonal antibody anti-Tac, and the anti-Tac light chain fused to PE40, a truncated derivative of Pseudomonas exotoxin. The active immunotoxin anti-Tac(Fab)-PE40 could be recovered from E. coli from either periplasm or renatured inclusion bodies. The double-chain immunotoxin was very cytotoxic toward IL2R-bearing cell lines, human activated T cells and fresh adult-T-cell-leukemia cells. The cytotoxicity was similar to that of anti-Tac(Fv)-PE40, the single-chain recombinant toxin containing only the variable domains of anti-Tac. IL2R-binding affinity was also equivalent to that of anti-Tac(Fv)-PE40, which is one-third that of anti-Tac. The serum half-life in mice was significantly prolonged as compared with anti-Tac(Fv)-PE40, with a beta phase of 430 vs. 57 minutes, but the LD50s were equivalent when the immunotoxins were administered in 3 daily doses. Anti-Tac(Fab)-PE40 was very cytotoxic in vitro toward transfected ATAC-4 carcinoma cells which express IL2Rs. In mice bearing ATAC-4 tumors, anti-Tac(Fab)-PE40 showed significant anti-tumor activity, inducing complete remissions in 80 and 100% of treated animals at approximately 7 and 14% respectively of the LD50. Anti-Tac(Fab)-PE40 was much more effective in vitro and in vivo than chemical conjugates between anti-Tac and truncated PE molecules. The recombinant Fab toxin should be studied further as potential treatment for IL2R-related malignancies, particularly if smaller recombinant immunotoxins have insufficient half-life in humans.

[Unspecified subarachnoid hemorrhage in Taiwan]

We report the epidemiological and clinical features of unspecified subarachnoid hemorrhage by reviewing the literature published in Taiwan. Data from stroke registry from January 1988 to June 1992 showed that 4.9% of 23910 acute strokes were diagnosed as subarachnoid hemorrhage; in about half of them the cause of hemorrhage was not specified due to lack of confirmatory diagnostic examinations or to rapid deterioration of consciousness subsequent to bleeding that made angiography unapplicable during hospitalization. The age distribution, sex ratio, clinical profiles and associated risk factors in this group of patients were similar to those in the group of aneurysmal rupture. Therefore, the majority of patients categorized in the group of unspecified subarachnoid hemorrhage very likely had aneurysmal ruptures. The causes of subarachnoid hemorrhage were more frequently undetermined in hospitals where neuroradiological as well as neurosurgical facilities and staff were not immediately available, and also in patients whose clinical condition was poor on arrival at the hospital or who deteriorated rapidly after the onset. These two facts may partly explain the higher case-fatality rate and poorer prognosis in patients whose causes of subarachnoid hemorrhage were undetermined and effective surgical treatment could not be done.

Benign osteoblastoma of the spine--report of two cases

Benign osteoblastoma is a rare spinal tumor, with the posterior element mainly involved. Symptoms do vary and there is a long diagnostic delay, especially in young people. We present two cases of benign osteoblastoma. One occurred in the atlas and presented with a painless neck mass. The other occurred in the lumbar spine with symptoms of long-term spinal pain and radicular pain. Preoperative Technetium bone scan and computed tomography (CT) resulted in exact localization and better operative planning. En bloc excision of tumor is indicated for complete pain relief and full return of spinal mobility.

Cytotoxicity of recombinant Fab and Fv immunotoxins on adult T-cell leukemia lymph node and blood cells in the presence of soluble interleukin-2 receptor

Single-chain immunotoxins anti-Tac(Fv)-PE40 and anti-Tac(Fv)-PE40KDEL, composed of variable domains of the anti-Tac monoclonal antibody and truncated forms of Pseudomonas exotoxin, have shown potent cytotoxic activity against malignant peripheral blood mononuclear cells (PBMCs) from adult T-cell leukemia (ATL) patients originating from the Caribbean. However, several clinically important issues have not previously been addressed. These include the potential of soluble interleukin 2 receptor in ATL patients to block immunotoxin effectiveness, the relative sensitivity of malignant lymph node cells (LNCs) versus PBMCs, the effect of an immunotoxin with a prolonged half-life, and finally whether ATL cells from patients in Japan have toxin sensitivity equal to those of the Caribbean patients. To resolve these questions, we studied 32 malignant PBMC and LNC samples from 30 ATL patients from Japan. PBMCs from 27 of 27 patients were very sensitive with 50% inhibition of protein synthesis achieved with 0.02-0.85 ng/ml (0.3-13 pM) of anti-Tac(Fv)-PE40KDEL or anti-Tac(Fv)-PE40. LNCs had sensitivity very similar to that of PBMCs in the five patients tested. The fully recombinant immunotoxin, anti-Tac(Fab)-PE40, which has 8-10 times the t1/2 alpha and beta compared to the Fv-immunotoxins, was also very cytotoxic toward cells from 27 of 27 patients tested with 50% inhibition of protein synthesis of 0.08-25 ng/ml. It was found that purified soluble interleukin 2 receptor added to the cytotoxicity assay decreased the cytotoxic activity of anti-Tac(Fv)-PE40KDEL or anti-Tac(Fab)-PE40, but that 1 x 10(4) units/ml or less had minimal competitive effects. It was found that ATL patients who have responded even incompletely to conventional chemotherapy have soluble interleukin 2 receptor levels lower than this at posttreatment. We conclude that recombinant immunotoxins containing anti-Tac(Fv) are effective against Japanese ATL PBMCs or LNCs and might be most effective if used in vivo after conventional chemotherapy. If it is found in humans that the effectiveness of single-chain recombinant toxins is limited by short half-life, anti-Tac(Fab)-PE40 should be considered as an alternative agent.

Two-dimensional left ventricular deformation during systole using magnetic resonance imaging with spatial modulation of magnetization

BACKGROUND

Myocardial tissue tagging with the use of magnetic resonance imaging allows noninvasive regional analysis of heart wall motion and deformation. However, any evaluation of the effect of disease or treatment requires a baseline reference of normal values and variation. We studied the two-dimensional motion of material points imaged within the left ventricular wall using spatial modulation of magnetization (SPAMM) in 12 normal human volunteers.

METHODS AND RESULTS

Five parallel short-axis and five parallel long-axis slices were acquired at five times during systole. SPAMM tags were generated at end diastole using a 7-mm grid. Intersection point data were analyzed for displacement, rotation, and torsion, and triangles of points were analyzed for local rotation and principal strains. Short-axis displacement was the least in the septum for all longitudinal levels (P < .001). Torsion about the long axis was uniform circumferentially because of the motion of the centroids used to reference the rotation. In the long-axis images, the base displaced longitudinally toward the apex, with the posterior wall moving farther than the anterior wall (13.4 +/- 2.2 versus 9.7 +/- 1.8 mm, P < .001) in this direction. The largest principal strain (maximum lengthening) was approximately radially oriented in both views. In the short-axis images, the minimum principal strain (maximum shortening) increased in magnitude toward the apex (P < .001) with little circumferential variation, except at midventricle, where the anterior wall showed greater contraction than the posterior wall (-0.21 +/- 0.03 versus -0.19 +/- 0.02, P < .02).

CONCLUSIONS

Consistent regional variations in deformation are seen in the normal human heart. Displacement and maximum shortening strains are well characterized with two-dimensional magnetic resonance tagging; however, higher-resolution images will be required to study transmural variations.

Surgical treatment for ossification of the posterior longitudinal ligament of the cervical spine

Ossification of the posterior longitudinal ligament (OPLL) is a degenerative disease of the spine, usually found in the cervical vertebrae. Most symptomatic patients present with a myelopathy or myeloradiculopathy. Surgical decompression is the preferred treatment. The choice of operative approach, anterior or posterior, is still controversial. From January 1986 to June 1992, 20 patients with this condition received operations at Chang Gung Memorial Hospital. The clinical manifestations and the results of treatment are analysed. The ideal surgery seems to be the anterior approach with bone fusion. If, however, the OPLL involves more than three segments, the posterior approach with an expansive laminoplasty would be the better alternative technique.

Eosinophilic granuloma of the skull--report of four cases

Eosinophilic granuloma is a benign form of the three clinical variants of histiocytosis-X. It is an uncommon, localized granulomatous process, forming solitary or multiple lytic skeletal lesions, and primarily involving male children and young adults. We studied 4 cases, three boys and one girl, aged 4, 8, 27 and 12 years, in Chang Gung Memorial Hospital from 1981 to 1990. Their common presentation was the rapidly growing, painful, and protruding scalp masses without neurological deficits. En bloc excisions of these lesions were performed. Then radiotherapy was given postoperatively in two cases, chemotherapy in one, and no adjuvant treatment in one. During their follow-up period of 2 to 10 years, all 4 patients were well, without evidence of recurrence.

The biochemical basis for the differential anti-human immunodeficiency virus activity of two cis enantiomers of 2',3'-dideoxy-3'-thiacytidine

Two cis stereoisomers of 2',3'-dideoxy-3'-thiacytidine (SddC) were investigated for their activity against human immunodeficiency virus type 1 (HIV-1) in human acute lymphoblastic leukemia H-9 cells. (-)-SddC is six times more potent against HIV-1 and at least 1.7-fold less cytotoxic than (+)-SddC. Metabolism studies showed that the intracellular accumulation of the active triphosphate form of (-)-SddC is more than 2-fold greater than that of (+)-SddCTP in H-9 cells. In contrast, (+)-SddCTP is approximately 1.5 times more potent than (-)-SddCTP as an inhibitor of HIV-1 reverse transcriptase using a rRNA template (Ki = 0.22 and 0.034 microM, respectively) and gapped DNA (Ki = 0.53 and 1.02 microM, respectively). The enantiomers are comparable as substrates for incorporation into DNA by the RNA-dependent HIV-1 reverse transcriptase; however, neither analog is incorporated as readily as dCTP. The above observations do not explain the difference in the anti-HIV potency between the enantiomers. A novel 3'-5' exonuclease was partially purified from the cytosol of H-9 cells and assayed for the removal of (+)- and (-)-SddCMP-terminated DNA. Removal of (+)-SddCMP was approximately two to three times faster from 3'-terminals of single-stranded and double-stranded DNA, whereas on DNA/RNA substrates, the exonucleolytic cleavage of (+)-SddCMP proceeded approximately six times faster than that of (-)-SddCMP. This result correlates with the observed difference in the anti-HIV effect between the two compounds and suggests that this novel enzyme may be an important determinant of their antiviral activities.

The expectant treatment of "asymptomatic" supratentorial epidural hematomas

Seventy-four patients with a traumatic epidural hematoma (EDH) and a Glasgow Coma Scale score of more than 12 received expectant treatment; 14 subsequently underwent surgical evacuation of the EDH. A patient with initial brain computed tomograms (CT) showing an EDH volume of more than 30 ml, a thickness of more than 15 mm, and a midline shift beyond 5 mm tended to require surgery within 3 days of the injury when the brain had exhausted its compensatory mechanism and yielded to the expanding EDH. After the 3-day period, in the absence of neurological symptoms, the presence of the EDH may not be an indication for surgical evacuation or hospitalization beyond 7 days. In our patients, the presence of a skull fracture in the temporal bone, the heterogeneous density of the EDH in the CT scan, or the 6-hour period between the CT study and the injury did not significantly increase the failure rate of nonsurgical treatment. Although a zero mortality was achieved in this series, these guidelines may not be applicable to the management of an infratentorial EDH.

Epidural hematomas in the posterior cranial fossa

A review of 89 cases of posterior fossa epidural hematoma (PFEDH) is presented. The mortality rate was 17.9%. In 44 cases (49.4%) there were associated intracranial hematomas. In 30 cases the hematoma was localized within the boundary of the foramen magnum and the transverse and sigmoid sinuses ("pure" PFEDH). In 59 cases the hematoma extended beyond the sinuses to the occipital area ("mixed" PFEDH). In the pure PFEDHs, the bleeder could be identified in only six cases and in five cases the source was a bleeding transverse sinus. The bleeders disclosed in the mixed PFEDHs were a torn transverse sinus in 28 cases, a meningeal artery in three cases, and a bony fracture in three cases. The possibility of a PFEDH should be kept in mind when evaluating patients who have suffered an occipital blow resulting in a frontal or temporal hematoma. In our series, patients with the pure PFEDHs with no associated intracranial hematomas had the best prognoses. Nine patients developed a PFEDH after surgery for a supratentorial hematoma. In 14 cases the PFEDH was treated at the subacute or chronic stage. All but one patient survived with a good recovery. Children generally had better prognoses.

Complete transection of common bile duct due to blunt abdominal trauma: a case report and literature review

A case of complete transection of the common bile duct due to abdominal blunt injury in a 49-year-old man is presented. The rarity of this injury and its initial presentation as a pancreatic pseudocyst warrant its description. This patient was diagnosed as having bile duct injury following ascites aspiration. Common bile duct transection was documented and a choledochostomy was done. However, bile leaked into the peritoneal cavity one week after the operation. A Roux-en-Y choledochojejunostomy was done successfully in a second operation. Delayed diagnosis is common in these kinds of injuries, but it should be considered when a patient has bile ascites, abdominal distention and jaundice after a blunt abdominal injury. A review of the literature, methods of diagnosis and the technique of surgical repair are described.

Cerebral sparganosis diagnosed and treated with stereotactic techniques. Report of two cases

Infestation of the central nervous system with sparganum, the larva of Spirometra mansoni, is rare. Only 27 cases have been reported in the literature; however, the true incidence might be underestimated. Two cases are reported that were definitively diagnosed by stereotactic biopsy techniques. Without a positive histological diagnosis, the first case would have been diagnosed as having a metastatic brain tumor and a course of radiotherapy would probably have been initiated. Differentiation between granuloma of cerebral sparganosis and brain tumors such as meningiomas, gliomas, and metastatic tumors is often difficult before operation. Detailed magnetic resonance imaging might offer some help in such cases. Emphasis is placed on the increasing importance of stereotactic surgery in the diagnosis and treatment of an intracerebral mass lesion, including cerebral sparganosis.

[Pituitary apoplexy: a study of eighteen cases]

Pituitary Apoplexy is a rare but sometimes life threatening condition which requires prompt recognition and timely medical intervention to avoid catastrophic consequences. From January 1979 to June 1989 and total of one hundred and ninety eight pituitary tumor patients were operated on our hospital. Eighteen cases (9.1%) were diagnosed "pituitary apoplexy" according to histopathological findings. The group consisted of twelve men and six women ranging in age from twenty two to sixty one years with a mean of forty. There were three cases of prolactin-secreting adenomas (16.7%), four growth-hormone secreting adenomas (22.2%), and eleven nonfunctional adenomas (61.1%) with an incidence of 6.1%, 8.3%, and 11.4% respectively (P > 0.05). Clinical manifestation occurred acutely in 66.7% and nonacutely in 33.3%. The patients presented with headaches (100%), visual impairment (83.3%), visual field defects (66%), disturbed consciousness (22%), fever and meningismus (11%). Radiological examinations able to demonstrate abnormalities included plain skull films (84%), computed tomography (84.6%), and angiography (93.8%). Various investigations of endocrine function pre and post operatively showed a deficient gonad axis (53%, 62.5%), adrenal axis (26.7%, 56.2%), and thyroid axis (20%, 43.8%). Sixteen cases received a transsphenoid operation and three cases underwent a transfrontal craniotomy. No case of mortality was reported. Postoperative radiotherapy was given to nine cases and nine cases were followed up on a regular basis. Therefore, our retrospective study suggests that pituitary apoplexy is not uncommon and has an acute clinical presentation. No particular tumor type was prone to occur. Various radiological examinations could define perisellar abnormalities. With a decreasing order of hormone deficiency, gonad, adrenal and thyroid axis were observed during the course of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemiparkinsonism in a patient with frontal meningioma

We report on a 44-year-old woman with a right frontal meningioma, who presented with resting tremor, rigidity and bradykinesia in the left limbs. There were no other neurologic manifestations. A computed tomography scan demonstrated a huge high-density mass in the right frontal lobe and marked surrounding edema causing compression of the basal ganglia. Cerebral angiography showed a typical sunburst tumor stain and three feeding vessels from the bilateral middle meningeal arteries and the right callosomarginal artery. The pathologic diagnosis was transitional type meningioma. Before surgery, treatment with levodopa and bromocriptine was significantly effective in controlling hemiparkinsonism, which completely disappeared after surgical removal of the tumor. This outcome supports the notion that local compression due to edema may cause a functional disorder in the basal ganglia producing reversible contralateral parkinsonism.

Biochemical pharmacology of (+)- and (-)-2',3'-dideoxy-3'-thiacytidine as anti-hepatitis B virus agents

2',3'-Dideoxy-3'-thiacytidine (cis-(+/-)-SddC) was found to have potent activity against hepatitis B virus and human immunodeficiency viruses in culture. Recent studies by us identified (-)-SddC as the stereoisomer responsible for the antiviral effect and showed that the cytotoxicity was mainly caused by (+)-SddC. Metabolism studies showed that these drugs were converted to their monophosphates, diphosphates, and triphosphates. The enzyme responsible for the formation of monophosphates was identified to be cytoplasmic deoxycytidine kinase in CEM cells. Uptake studies showed that the intracellular concentration of (-)-SddC and its metabolites was approximately 5-fold higher than that of (+)-SddC metabolites. (-)-SddCTP was more potent than (+)-SddCTP in inhibiting hepatitis B virus replication; (+)- and (-)-SddCTP exhibited minimal inhibition on polymerases alpha and delta, more inhibition on beta, and strong inhibition on gamma. In all cases, (+)-SddCTP was found to be more inhibitory than (-)-SddCTP to all four polymerases. (+)-SddCMP competed with dCTP for incorporation into DNA by DNA polymerase gamma and beta and served as a chain terminator; however, similar incorporation was not detected using other polymerases. The selective inhibition of DNA synthesis in isolated mitochondria by (+)- and (-)-SddCTP suggests a stereospecificity on the mitochondrial uptake of deoxynucleoside triphosphates.

Deoxycytidine deaminase-resistant stereoisomer is the active form of (+/-)-2',3'-dideoxy-3'-thiacytidine in the inhibition of hepatitis B virus replication

2',3'-Dideoxy-3'-thiacytidine (+/-)-SddC) was found to have potent activity against human hepatitis B virus as well as human immunodeficiency viruses in culture. The (-)form ((-)-SddC) which is resistant to deoxycytidine deaminase was found to be the more active antiviral stereoisomer than the (+)-form ((+)-SddC). The (+)-SddC is susceptible to deamination by deoxycytidine deaminase and is 25- and 12-fold more toxic than (-)-SddC in CEM cells in terms of anti-cell growth and anti-mitochondrial DNA synthesis, respectively. Similar results were obtained using a mixture of their 5-fluoro analogs ((+/-)-FSddC). Unlike 2',3'-dideoxycytidine, which is a potent inhibitor of mitochondrial DNA synthesis and results in such delayed toxicity as peripheral neuropathy with long term usage, (-)-SddC does not affect mitochondrial DNA synthesis. The (-)form is phosphorylated to (-)-SddCMP and is subsequently converted to (-)-SddCDP and (-)-SddCTP. One additional major metabolite which has been tentatively assigned the name "(-)-SddCMP sialate" was also identified. No significant difference in terms of the profiles of the metabolites was found between 4 and 24 h. There is an appreciable amount of (-)-SddCTP detectable 24 h after removal of the drug. (-)-SddCTP was also found to be approximately 3-fold more potent than (+)-SddCTP in inhibiting human hepatitis B virus DNA polymerase. This is the first nucleoside analog with the unnatural sugar configuration demonstrated to have antiviral activity.