Clinical application of perfusion and diffusion MR imaging in acute ischemic stroke

With the advances in new neuroimaging modalities, the role of imaging of acute ischemic stroke has broadened and progressed from making diagnoses to providing valuable information for patient management. The goal of thrombolytic therapy for acute ischemic stroke should be to salvage the ischemic tissue reversibility that can respond to recanalization and avoid reperfusion of the dead (nonviable) tissue. It is essential to have rapid diagnostic modalities that can distinguish viable ischemic tissue from irreversibly damaged tissue, because there is a risk of reperfusion injury such as hemorrhagic complications with early intervention. Although diffusion magnetic resonance (MR) imaging has been reported to have a high sensitivity and specificity for acute ischemia in acute stroke patients without early reperfusion therapy, the capability to differentiate reversible from irreversible ischemia by diffusion MR imaging has not been established. Perfusion MR imaging techniques provide direct information on parenchymal perfusion status (adequacy of the collateral circulation) and may have the potential for providing important information about tissue viability and/or reversibility for selecting appropriate patients for thrombolytic therapy.

Delayed ischemic hyperintensity on T1-weighted MRI in the caudoputamen and cerebral cortex of humans after spectacular shrinking deficit

BACKGROUND AND PURPOSE

Transient internal carotid artery (ICA)-middle cerebral artery (MCA) occlusion caused by cardiogenic embolus can lead to spectacular shrinking deficit (SSD): sudden hemispheric stroke syndrome followed by rapid improvement. The aim of this study was to investigate sequential neuroradiological changes in the brains of patients after SSD compared with those after brief cardiac arrest and hypoglycemia, which we previously studied with the same methods.

METHODS

We serially studied CT scans and MR images obtained at 1.5 T in 4 patients with SSD. All 4 patients suffered from transient neurological deficits due to cardiogenic embolus in ICA-MCA. The symptoms began to disappear from 25 to 50 minutes after onset.

RESULTS

Repeated CT scans demonstrated no abnormal findings in the affected cerebral hemisphere in 3 of the 4 patients and a small cortical infarct in the remaining 1. In each patient, repeated MRI between day 7 and month 23 after stroke showed basal ganglionic and cortical lesions. These lesions were hyperintense on T1-weighted and relatively hypointense on T2-weighted imaging. These ischemic lesions of hyperintensity on T1-weighted MRI subsided with time.

CONCLUSIONS

Transient ICA-MCA occlusion leading to SSD produces a specific ischemic change with delayed onset in the basal ganglia and cerebral cortex in humans on MRI but not CT scans. We speculate that the lesions represent incomplete ischemic injury, including selective neuronal death, proliferation of glial cells, paramagnetic substance deposition, and/or lipid accumulation. Unlike brief cardiac arrest or hypoglycemia, the localized lesions on MRI of patients after SSD seem to be incomplete and to differ from infarction or hemorrhage.

Novel brain ischemic change on MRI. Delayed ischemic hyperintensity on T1-weighted images and selective neuronal death in the caudoputamen of rats after brief focal ischemia

BACKGROUND AND PURPOSE

Specific change of persistent hyperintensity/hypointensity on T1-weighted (T1W) and T2-weighted (T2W) MRI, respectively, has been reported to develop in the human basal ganglia after brief hemispheric ischemia. We investigated whether this ischemic change observed in humans could be reproduced experimentally in rats after brief middle cerebral artery (MCA) occlusion (MCAO), and if so, what the neuroradiological change represented histologically.

METHODS

The origin of the right MCA of male Wistar rats (n=25) was occluded for 15 minutes by inserting a silicon-coated nylon thread from the external carotid artery into the internal carotid artery. After 15 minutes' MCAO, coronal MR images (T1W, T2W, and T1W with fat saturation pulse) were obtained once at 3-day reperfusion (n=5) and twice at 3- and 7-day reperfusion (n=20). Brain specimens were examined histologically immediately after the last MRI study in all rats.

RESULTS

Neither T1W nor T2W MRI showed marked signal changes 3 days after reperfusion following 15-minute MCAO. However, the ischemic change of hyperintensity and hypointensity on T1W and T2W MRI, respectively, appeared in the striatum following 7-day reperfusion after 15-minute MCAO (n=19/20). Histological examination revealed that the specific lesion in the rat striatum on MRI corresponded to selective neuronal death and proliferation of reactive astrocytes and microglia without infarct, hemorrhage, lipid accumulation, or calcification.

CONCLUSIONS

Brief MCAO with reperfusion induces the delayed ischemic changes of hyperintensity and hypointensity on T1W and T2W MRI, respectively, in the rat striatum with high reproducibility. This specific ischemic change on MRI histologically corresponded to selective neuronal death and gliosis with preservation of the macroscopic structure of the brain. A similar MRI pattern reported in patients who have sustained brief ischemia may represent similar histology. We speculate that the ischemic change reflects some biochemical changes affecting the magnetic field as the brain tissue undergoes subtle structural changes.

Efficacy of Palmaz Stent Deployment for Subclavian Artery Stenosis

Percutaneous angioplasty is a useful method for improvement of posterior circulation of the brain in subclavian artery stenosis and occlusion. Recently, the Palmaz stent was introduced for peripheral vessels stenosis. We evaluated the efficacy and care point of Palmaz stent deployment for subclavian artery stenosis in seven cases (5 stenosis and 2 occlusion) with symptoms and a mean age of 65.1 years. The stents could be deployed exactly at the stenotic region in all cases.

The pressure gradient disappeared in all cases, and the clots were fixed between vessel wall and stent. Antegrade circulation and significant clinical symptoms improvement were obtained in all cases. In angioplasty of subclavian artery stenosis, as compared with balloon angioplasty alone, Palmaz stent is a very useful device with fewer complications including distal thrombosis of the vertebrobasilar circulation.

Age correlation of the time lag in signal change on EPI-fMRI

PURPOSE

We measured the time lags between the start or end of tasks and signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags.

METHODS

Forty subjects, 20-76 years old, were evaluated. fMRI was performed with and echo planar imaging sequence at 0.5 s intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after starting the task (T-inc) and the time to reach the initial level after ceasing the task (T-dec).

RESULTS

Average T-inc was 3.09 s and T-dec was 6.63 s. The values of T-inc could be correlated to age. T-dec had no age correlation.

CONCLUSION

The time lag in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time lag in fMRI is influenced by some factors associated with aging.

A new pharyngitis model using capsaicin in rats

1. Application of capsaicin solution onto the rat pharyngeal mucosa caused a well-reproducible increase in vascular permeability in the pharynx. 2. Capsaicin-induced pharyngeal inflammation was unaffected by a histamine H1 blocker and non-steroidal anti-inflammatory agents, whereas dexamethasone was effective in its inhibition. 3. FK224, a dual antagonist of tachykinin NK1 and NK2 receptors, and FK888, a selective antagonist of NK1 receptor, significantly inhibited capsaicin-induced plasma exudation in the pharynx. 4. In capsaicinized animals, the application of capsaicin solution in the pharyngeal mucosa did not induce pharyngitis. 5. These results suggest that the mechanism of the capsaicin-induced pharyngitis primarily involves tachykinins.

Normal myelination of anatomic nerve fiber bundles: MR analysis

PURPOSE

In order to establish milestones of brain maturation by MR imaging, we examined the initiation of myelination of fiber bundles and of surrounding white matter.

METHODS

The subjects included 54 healthy infants ranging in age from 35 to 145 weeks by corrected gestational age. Images were obtained on a 1.5-T MR unit. In 24 sites of 18 fiber bundles in eight cross sections obtained perpendicular to the long axis of the brain stem, we analyzed the initiation of myelination and the age at which fiber bundles become indistinguishable owing to myelination of the surrounding white matter (blurring).

RESULTS

The fiber bundles were classified into two groups on the basis of the presence or absence of blurring. The first group (no blurring) was further divided into group 1A, in which myelination began at 35 weeks or less, and group 1B, in which myelination began at 44 weeks or later. The second group (blurring) was divided into group 2A, in which myelination began at 35 weeks or less and blurring occurred at 43 to 49 weeks; group 2B, in which myelination started at 35 weeks or less and blurring began at 67 to 145 weeks; and group 2C, in which myelination began at 36 weeks or later and blurring occurred at 67 to 145 weeks.

CONCLUSION

The time of blurring, when myelinated fiber bundles become indistinguishable from surrounding white matter owing to the initiation of myelination, is considered to be a useful parameter of brain maturation in infancy.

Long-term palliative treatment of hepatocellular carcinoma extending into the portal vein and bile duct by chemoembolization and metallic stenting

We present a patient with hepatocellular carcinoma accompanied by portal vein and bile duct tumor thrombi. The patient was treated with a spiral Z-stent covered by a polyethylene sheet placed in the bile duct, a Wallstent placed in the portal vein, chemoembolization, and external radiation therapy. The patient is alive with patency of both endoprostheses 18 months later.

[Correlation between MR imaging and histopathological findings of cystic metastatic brain tumors]

To clarify the correlation between the histopathological findings and MR signal intensity of the cyst wall, fifteen cystic metastatic brain tumors of eleven patients were imaged using a 0.5T MR unit just before surgery, and the MRI findings were correlated with the histopathological findings of resected lesions. On T2-weighted images, all cyst walls showed hypointensity. On T1-weighted images, the intensity of the cyst wall could be classified into three groups, compared with the cerebral cortex. Walls with hyperintensity on T1WI(group H; n = 6) consisted of ample tumor cells, blood vessels and connective tissues, suggesting viable tumor cells. Iso-intense walls on T1W1(group I; n = 3)had abundant reactive glial tissues. Hypointense walls on T1W1 (group L; n = 5)revealed hemorrhage and/or hemosicerin in the wall, suggesting hemorrhagic necrosis. Thus a good correlation was demonstrated between the MR signal intensities and histopathological findings of cyst walls of cystic metastatic brain tumors. This may contribute not only to more precise diagnosis on MRI but also to more planning for treatment of cystic brain metastases.

Cine-magnetic resonance imaging evaluation of communication between middle cranial fossa arachnoid cysts and cisterns

Cine-magnetic resonance (MR) imaging examinations were performed in 10 patients with middle cranial fossa arachnoid cysts to evaluate communication between the cysts and the normal cerebrospinal fluid (CSF) space. Eight of 10 patients were evaluated by time of flight cine-MR imaging, and two by phase contrast cine-MR imaging. Two patients underwent membranectomy of the cysts, and were evaluated both pre- and postoperatively. Computed tomography cisternography was used to confirm communication between the cysts and the surrounding cisterns. Pulsatile fluid motion within the cysts was present in all patients. However, marked fluid motion and jet flow between the cysts and the surrounding cisterns were only observed in communicating cysts. In the two patients who underwent membranectomy, postoperative examination found greater fluid motion and jet flow not previously present. Cine-MR imaging demonstration of marked pulsatile fluid motion accompanied by jet flow suggests that a cyst communicates with the normal CSF space.

Fast fluid-attenuated inversion recovery (FAST-FLAIR) of ischemic lesions in the brain: comparison with T2-weighted turbo SE

PURPOSE

We compared fast fluid-attenuated inversion recovery (FAST-FLAIR) images with Turbo SE T2-weighted images to evaluate the detectability of small ischemic lesions in the brain.

MATERIALS AND METHODS

Thirty-six cases of multiple cerebral ischemic lesions were examined with FAST-FLAIR and Turbo SE imaging. The detectability of lesions, ability to discriminate lesions from the cortex, visualization of perivascular space, and visualization of brainstem lesions were compared between the two sequences.

RESULTS

The total number of lesions detected on both sequences was 534 in 36 cases. Six lesions in three cases were detected only on FAST-FLAIR, and one lesion in one case was detected only on the Turbo SE. All the 52 lesions located close to the cortex could be discriminated from the cortex on the FAST-FLAIR images, while 23 of these lesions could not be discriminated on the Turbo SE. Perivascular spaces were not visualized as areas of high signal on the FAST-FLAIR images. Pontine lesions that were visualized in four cases were clearer on the Turbo SE images than on the FAST-FLAIR images.

CONCLUSION

The FAST-FLAIR images were shown to be useful in the detection of ischemic lesions and in distinguishing them from the surrounding normal structures. The FAST-FLAIR sequence is expected to become a new additional routine sequence.

[A case of Hangman's fracture associated with vertebral arteriovenous fistula treated with trapping]

A case of a traumatic vertebral arteriovenous fistula associated with a hangman's fracture is reported. A 45-year-old male fell down about 2 meters and struck his parietooccipital region against the ground. Profuse nasal bleeding developed. He was transferred to a local hospital, where his respiration was ataxic and blood pressure was low. After intubation, he was transferred to our emergency department. Cervical x-p revealed fracture of C1, C2 and subluxation of C2 body. Because of uncontrollable nasal bleeding, the bilateral maxillary arteries were embolized with spongel. At this time, right vertebral angiograms demonstrated a vertebral arteriovenous fistula with an pseudoaneurysm located at C2 level. On the 13th hospital day, direct balloon occlusion of the fistula was attempted; this could not be achieved because the subclavian and vertebral arteries were tortuous and the balloon catheter could not be introduced to the level of the fistula in the vertebral artery. The patient was only observed until follow-up angiogram on the 24th hospital day revealed enlargement of the pseudoaneurysm. We performed trapping of both the proximal and distal ends of the involved vertebral artery; from C5 to C1. Postoperative course was uneventful, hangman's fracture was fixed with a Halo vest. Four months after operation, fistula and pseudoaneurysm were not opacified on angiogram. We believe that transvascular techniques are the treatment of choice for vertebral arteriovenous fistulas. However, as the next best thing, we can use trapping for the patient whose vessels are too tortuous to introduce the balloon catheter to the involved vessel.

1,25(OH)2-vitamin D3 mediated changes in mRNA for c-myc and 1,25(OH)2D3 receptor in HL-60 cells and related subclones

HL-60 cells have been shown to differentiate into monocyte-like cells as a consequence of the interaction of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) with a specific intracellular receptor (VDR). Of c-myc it has been reported that it plays a role in cell proliferation and differentiation. We have investigated the expression of VDR and c-myc mRNA of three subclones of HL-60 cells (N, R and MR) after exposure to 1,25(OH)2D3. The N cell is a normal clone in which 1,25(OH)2D3 inhibited cell proliferation and also induced cell differentiation. The R cell is a resistant clone whose proliferation and differentiation are not affected by 1,25(OH)2D3. The MR cell is a mixed response type clone whose proliferation was not inhibited by 1,25(OH)2D3, while its differentiation was actually induced by 1,25(OH)2D3. The VDR mRNA expression of the N and MR cells reached a peak at 2 h (2.3- and 2.6-fold induction, respectively) and returned to the control level after 24 h treatment of 1,25(OH)2D3. The c-myc mRNA expression was significantly inhibited in the 1,25(OH)2D3-induced N cells, but not in the MR cells. In contrast, 1,25(OH)2D3 did not induce any changes of the VDR and c-myc mRNA levels in the R cells. In separate experiments, the level of the VDR in the three clones was determined via Scatchard analysis; the VDR of the N, MR and R cells were found to be 4500/cell, 3570/cell and less than 600/cell, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline phosphatase activity in the human promyelocytic leukemia cell line, HL-60, induced by retinoic acid and recombinant human granulocyte colony-stimulating factor

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) not only enhanced the growth of HL-60 cells, but also significantly increased NBT-reducing ability and alkaline phosphatase (ALP) activity of the cells, which were enhanced by the treatment with retinoic acid (RA). Protein kinase C inhibitors (H-7 and staurosporine) significantly suppressed this induction of ALP. The pretreatment with RA followed by rhG-CSF treatment showed almost the same degree of ALP activity as that induced by the simultaneous treatment with RA and rhG-CSF. This study suggests that RA and rhG-CSF are the potent inducers of ALP activity of HL-60 cells and protein kinase C is supposed to have a role in this induction of ALP.

[Six cases of therapy related leukemia; case reports and review of the literature]

The following presents 6 cases of therapy related leukemia (TRL) along with discussion of their clinical features in comparison with those previously reported in Japan. Common primary malignancies were mammalian cancer, lung cancer and malignant lymphoma in both groups. It was observed that, 1) average age was higher (68 years), 2) average latent period from primary malignancy to leukemia was longer (10 years), particularly in patients treated solely with radiation, 3) in 4 out of 6 patients (67%) karyotype analysis of leukemia cells showed normal results, but in one case previously administered etoposide, translocation involving 15q+, 17q- was noted, and 4) the CR ratio in our cases was 83%; half the cases are still alive at 10 months of follow-up, while in previously reported cases the CR ratio was 41%, and the median survival time was 12 months according to Kaplan-Meier analysis. Although poor response to conventional chemotherapy has been reported in TRL patients, the present data indicated TRL in some cases to achieve complete response and long-term survival. Aggressive chemotherapy should be considered for such patients.

Streptococcus mitis septicemia in leukemia patients; clinical features and outcome

The frequency of streptococcal infections has been reported to be increasing. To determine the significance of such infections complicating treatment of leukemia, we studied the incidence and clinical features of Streptococcus mitis septicemia among 51 leukemia patients in our department. During 166 consecutive treatment courses for leukemia, eight episodes of Streptococcus mitis septicemia were observed in 35 septicemic patients. In seven out of eight episodes (88%), severe mucositis developed after aggressive chemotherapy, suggesting that oral mucosa might be the site of entry for Streptococcus mitis. The isolates were sensitive to imipenam/cilastatin and cefuzonam, and were relatively resistant to amikacin. Although none of the patients died of Streptococcus mitis septicemia, life-threatening adult respiratory distress syndrome (ARDS) developed in two independent treatment courses. We should thus be aware of the risk of ARDS in patients with Streptococcus mitis septicemia.

[Treatment of adult acute lymphoblastic leukemia with DCVP-l-asp protocol]

From 1985 to 1991, 20 patients with adult acute lymphoblastic leukemia (ALL) were treated with the DCVP-l-asp protocol, which consists of daunorubicin, cytosine arabinoside, vincristine, prednisolone, and I-asparaginase. of these 17 patients (85%) achieved complete remission. A Kaplan-Meier analysis predicted that 30% of the patients in remission would remain disease-free at 5 years. Four patients relapsed between 1 and 2.5 years from the start of treatment. The median survival time for the four patients with an abnormal karyotype was 15 months. No meningeal relapses occurred in patients treated with regular CNS prophylaxis. Myelosuppression was severe, but was well tolerated with supportive therapy, and there were no treatment-related deaths. We conclude that DCVP-l-asp is a feasible and effective protocol for adult ALLs including elderly patients. However, new treatment modalities, such as bone marrow transplantation, should be explored in patients with unfavorable prognostic factors.

[Hematological study in 27 patients with myelodysplastic syndrome (MDS)]

The clinical, histologic, and cytogenetic features of myelodysplastic syndrome (MDS) were analyzed in 27 patients consisting of 21 males and 6 females (M: F ratio = 3.5:1) whose median age was 60.9 years. Analysis of the peripheral blood of the patients revealed pancytopenia (8 patients), bicytopenia (12), and cytopenia in one cell lineage (5). The patients had high serum iron value and low UIBC value. More than 20% of all erythroid cells in the bone marrow consisted of ringed sideroblasts in not only RARS patients but also RAEB, CMMoL, and RAEB-T patients. Morphological changes of the bone marrow cells were observed in patients with all types of MDS. Eighty percent and 60% of RAEB and RAEB-T patients, respectively, showed trilineage myelodysplasia. Chromosomal abnormalities were observed in 52% of MDS patients. The rate of leukemic transformation was high in RAEB, CMMoL, and RAEB-T patients.

Acute myelocytic leukemia associated with thrombocytosis and inv 3(q21.3; q26.2) in a case of Grönbland-Strandberg syndrome

Grönbland-Strandberg syndrome is an inherited connective tissue disorder with cutaneous, ophthalmologic, and systemic manifestations. Here we report a case of AML with thrombocytosis arising in a patient with this syndrome. Karyotypic analysis of bone marrow cells revealed the inversion 3 (q21.3;q26.2). To our knowledge, this is the first report of the association of AML with thrombocytosis and Grönbland-Strandberg syndrome. This might be a coincidental association, but it suggests some interesting speculations regarding the pathogenesis of these diseases.

[The effects of retinoic acid and recombinant human granulocyte colony-stimulating factor on alkaline phosphatase activity of HL-60 cells]

We examined alkaline phosphatase (ALP) activity in the HL-60 cell induced by retinoic acid (RA) and recombinant human granulocyte colony-stimulating factor (rhG-CSF). rhG-CSF induced a small but significant increase of NBT-reducing ability and ALP activity of the HL-60 cells. Among various inducers of cell differentiation, 1,25(OH)2D3 and dimethylsulfoxide (DMSO) caused the increase of the NBT-reducing ability and the suppression of ALP activity induced by rhG-CSF, while RA enhanced both of them. Protein kinase C inhibitors (H-7 and staurosporine) but not a protein kinase A inhibitor (HA1004) significantly suppressed the ALP activity induced by the simultaneous treatment with RA and rhG-CSF.

Post-splenectomy meningitis in patients with lymphoid malignancy

This report describes pneumococcal meningitis in two splenectomized patients with lymphoid malignancy. Early diagnosis and emergency treatment of pneumococcal infection in splenectomized patients is proven to be of significant value. Prophylactic antibiotics targeted against pneumococcus should be considered for the clinical management of such conditions in splenectomized patients, particularly during cytotoxic chemotherapy.

Characterization, growth, and differentiation of a human myeloid leukemia cell line, TI-1 cell

A cell line (TI-1) has been established from the peripheral blood of a patient with acute myeloid leukemia (M2). A typical TI-1 cell displayed many abnormalities of its chromosomes, but not the Philadelphia (Ph1) chromosome. Light and electron microscopic examination and histochemical analysis indicated that the TI-1 cells were undifferentiated blast cells, but immunologic marker studies suggested that these cells had myeloid characteristics. The proliferation of TI-1 cells was dependent on the concentration of fetal bovine serum (FBS). Their doubling time was 13.8 hours when they were cultured in a medium containing 10% FBS. Phorbol-12 myristate 13-acetate (PMA) induced the TI-1 cells to differentiate into monocyte-like cells, as judged by their morphologic similarity to monocytes, their adhesion to the culture dish, and their increase of both nitroblue tetrazolium (NBT)-reducing ability and nonspecific esterase (NSE)-activity. PMA significantly inhibited the proliferation and DNA synthesis of TI-1 cells in a dose-dependent manner. The PMA-induced differentiation was significantly inhibited by the protein kinase C inhibitors (H-7, staurosporine). Hemin induced the TI-1 cells to differentiate into erythroid cells. The number of hemoglobin-producing cells and hemoglobin production was increased by hemin treatment. Hemin also inhibited the proliferation of the TI-1 cells. Thus, the TI-1 cell represents a bipotent, granulo-monocytoid, and erythroid cell line. The TI-1 cell line will be a useful model for monocytoid and erythroid differentiation.

1,25(OH)2-vitamin D3, a steroid hormone that produces biologic effects via both genomic and nongenomic pathways

The hormonally active form of vitamin D is 1,25(OH)2-vitamin D3 [1,25(OH)2D3]. This seco-steroid is the key mediator of the vitamin D endocrine system which produces biological effects in over 28 target tissues. In these target tissues, the biological responses may be generated both by a signal transduction mechanism which involves a nuclear receptor for 1,25(OH)2D3 that modulates gene transcription or a signal transduction pathway which involves rapid opening of Ca2+ channels which are externally located on the plasma membrane. This paper reviews the evidence in support of the pleiotropic effects of this steroid hormone and presents evidence that the receptor of the genomic effects is likely to be separate from the receptor/membrane recognition element which initiates the rapid nongenomic biological effects.

Mechanism of transient increase in intracellular concentration of free calcium ions in HL-60 cell differentiation induced by vitamin D3 and phorbol ester

A promyelocytic leukemia cell line, HL-60, was induced to differentiate into monocyte-macrophage lineage cells by treatment with active vitamin D3 and phorbol esters, and into granulocyte lineage ones by retinoic acid and dimethylsulfoxide. The changes in intracellular concentration of free calcium ions ([Ca2+]i) were measured and analyzed by calcium-imaging analysis with Fura 2-AM. A significant and transient increase in [Ca2+]i was observed in active vitamin D3 and phorbol ester systems; however, no change was detected with retinoic acid and dimethylsulfoxide. This increase was due to the influx of calcium ions from outside of the cells, and L-type calcium channels were shown to mainly contribute to this influx. Protein kinase C was also shown to be involved in the increase in [Ca2+]i.

Induction of differentiation of HL-60 cells by protein kinase C inhibitor, K252a

To clarify the role of protein kinase C and protein kinase A in cell proliferation and differentiation, the effects of K252a and its derivatives (K252b, KT5720), which have different inhibitory activity to these protein kinases, on the proliferation and differentiation of HL-60 cells were investigated. The proliferation and DNA synthesis of the HL-60 cells were inhibited by K252a in a dose dependent manner. However, K252b and KT5720 which are more specific inhibitors of protein kinase C or protein kinase A, respectively, had no observable effect on cell proliferation. K252a (40nM) enhanced the differentiation of HL-60 cells induced by 1,25(OH)2D3, retinoic acid and DMSO. K252b and KT5720 did not affect 1,25(OH)2D3-induced differentiation. K252a significantly inhibited the differentiation induced by PMA. These results demonstrate that K252a but not its derivatives can function as an antitumor drug and enhancer of the differentiation induced by various inducers.

The role of Ca2+ and protein kinase C in the differentiation of HL-60 cells induced by 1 alpha,25(OH)2D3 and diltiazem

The roles of calcium (Ca2+) and protein kinase C in the differentiation of HL-60 cells induced by 1 alpha,25(OH)2D3 (D3) and/or a Ca2+ antagonist, diltiazem(D-cis, L-cis), were elucidated. D3 and diltiazem (100 microM) inhibited cell proliferation, and diltiazem enhanced the D3-induced differentiation. There was no difference in potency between the two isomers of diltiazem in the enhancing activity, in spite of their different pharmacological activity. The concentration of free Ca2+ in the HL-60 cells following D3 and/or diltiazem treatment significantly increased. A protein kinase C inhibitor, H-7, inhibited the phenotypic differentiation induced by D3. These results suggest that Ca2+ and protein kinase C play an important role in the differentiation of HL-60 cells induced by D3 and diltiazem.

[Therapeutic effect of ranimustine (MCNU) on essential thrombocythemia and polycythemia vera]

Seven patients with essential thrombocythemia and two patients with polycythemia vera were treated with ranimustine (MCNU). MCNU was given intravenously by drip infusion at a dose of 40-80 mg/m2 with intervals arranged in terns of the counts of both white blood cell and platelets. All cases with essential thrombocythemia obtained complete response, but the cases with polycythemia vera needed the combination of phlebotomy. The therapeutic effects were maintained for 2-5 months. No serious side effect was recognized except in two cases (22%) of mild nausea. Our study indicates that MCNU is useful for chemotherapy of chronic myeloproliferative disorders, especially, essential thrombocythemia.

[VAMA salvage regimen (VP-16, ARA-C, MTX and L-asparaginase) in relapsed or resistant non-Hodgkin's lymphoma]

A new salvage treatment protocol consisting of VP-16, cytosine arabinoside (Ara-C), methotrexate (MTX) and L-asparaginase, known as VAMA, was administered to twelve patients with relapsed or resistant non-Hodgkin's lymphoma. All twelve patients were in advanced stage with aggressive histologic type. Four of eight patients whose tumor cells had been immunologically determined, had T-cell phenotype. Three complete and five partial responses were obtained, for an overall response rate of 67%. It is of particular interest that all four patients with T-cell phenotype responded(CR; 3 cases, PR; 1 case), and a CR duration over 31 months has been achieved in a case of T-lymphoblastic lymphoma. Severe myelosuppression was the major toxic effect, but it was generally well-tolerated with supportive therapy. These results indicate that VAMA salvage regimen can play an important role in the treatment of relapsed or resistant non-Hodgkin's lymphoma.

[Treatment of myelodysplastic syndrome and acute myelogenous leukemia with vitamin D3 [1 alpha(OH)D3]]

It is known that 1 alpha, 25(OH)2D3 is an inducer of nonlymphoid leukemic cell differentiation to monocyte-macrophage-like in vitro. The effects of oral administration of 4.5-15 micrograms/d 1 alpha (OH)D3, which is converted to 1 alpha, 25(OH)2D3 in vivo by liver cells, on leukemic cells were studied in two patients with AML and one with RAEB. In these three cases, 1 alpha (OH)D3 reduced the number of leukemic cells in the bone marrow and aggregated the dispersed chromatin of leukemic cells as heterochromatin. Furthermore, this drug induced atypical lymphocyte-like cells, which were considered to be differentiated from leukemic cells in case 1, and improvement of pancytopenia in case 3. While hypercalcemia developed during 1 alpha (OH)D3 therapy in case 1, it disappeared within three days after discontinuation. We also studied the in vitro effects of 1 alpha, 25 (OH)2D3 on leukemic cells freshly isolated from the bone marrow in these three cases. After incubation with 10(-8) M 1 alpha, 25(OH)2D3 at 37 degrees C for 72 h, the number of adherent cells on the bottom of Petri dishes had increased. These cells were quite similar to monocyte-macrophages. These leukemic cells, after differentiation induced by 1 alpha, 25(OH)2D3, reacted strongly with monoclonal antibodies My-4 and My-7. Both 100 microM D-cis and L-cis diltiazem (calcium channel blocker) enhanced the differentiation of HL-60 cells induced by 1 alpha, 25 (OH)2D3. There was no significant difference between D-cis and L-cis diltiazem with regard to this enhancing effect. The cytoplasmic free Ca2+ concentration in HL-60 cells induced by 1 alpha, 25(OH)2 D3 and/or diltiazem, was increased significantly as compared with that in HL-60 cells incubated without inducers.

[Treatment with K-18 (IgG-melphalan) in recurrent cases of hematopoietic malignancies]

K 18, an IgG-Melphalan conjugate was administered to 30 patients, who had recurrent hematopoietic malignancy. Ten out of the 30 patients received single doses of 1 to 20 enteric tablets containing 10 mg of K 18, as a phase I study. No side effects were observed. K 18 was administered every day to the remaining 20 patients in order to evaluate the side effects and therapeutic effects, as a phase II study. One patient attained partial remission. Although no remission effect was obtained in 14 of the 20 patients, antitumor effects such as a decrease in leukemia cells, were observed in 4 of 20 patients. As to side effects, neither recurrence of tumor nor cumulative toxicity were shown in one patient with NHL who received only K 18 for 14 months as maintenance therapy. Evaluation of antitumor effect was difficult in the case of the remaining 4 patients. In the 20 cases who entered the phase II study, a decrease in neutrophils was observed in 2 patients, a slight decrease in platelets in 3 patients and increased transaminase activity in one patient as side effects of K 18. In brief, compared with Melphalan, K 18 has between 1.3 and 2 times a more potent therapeutic effect, with extremely low side effects.