HDL and the inflammatory response induced by LDL-derived oxidized phospholipids

Oxidation of low density lipoprotein (LDL) phospholipids containing arachidonic acid at the sn-2 position occurs when a critical concentration of "seeding molecules" derived from the lipoxygenase pathway is reached in LDL. When this critical concentration is reached, the nonenzymatic oxidation of LDL phospholipids produces a series of biologically active, oxidized phospholipids that mediate the cellular events seen in the developing fatty streak. Normal high density lipoprotein (HDL) contains at least 4 enzymes as well as apolipoproteins that can prevent the formation of the LDL-derived oxidized phospholipids or inactivate them after they are formed. In the sense that normal HDL can prevent the formation of or inactivate these inflammatory LDL-derived oxidized phospholipids, normal HDL is anti-inflammatory. HDL from mice that are genetically predisposed to diet-induced atherosclerosis became proinflammatory when the mice are fed an atherogenic diet, injected with LDL-derived oxidized phospholipids, or infected with influenza A virus. Mice that were genetically engineered to be hyperlipidemic on a chow diet and patients with coronary atherosclerosis, despite normal lipid levels, also had proinflammatory HDL. It is proposed that LDL-derived oxidized phospholipids and HDL may be part of a system of nonspecific innate immunity and that the detection of proinflammatory HDL may be a useful marker of susceptibility to atherosclerosis.

Role for peroxisome proliferator-activated receptor alpha in oxidized phospholipid-induced synthesis of monocyte chemotactic protein-1 and interleukin-8 by endothelial cells

The attraction, binding, and entry of monocytes into the vessel wall play an important role in atherogenesis. We have previously shown that minimally oxidized/modified LDL (MM-LDL), a pathogenically relevant lipoprotein, can activate human aortic endothelial cells (HAECs) to produce monocyte chemotactic activators. In the present study, we demonstrate that MM-LDL and oxidation products of 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (PAPC) activate endothelial cells to synthesize monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8). Several lines of evidence suggest that this activation is mediated by the lipid-dependent transcription factor peroxisome proliferator-activated receptor alpha (PPARalpha), the most abundant member of the PPAR family in HAECs. Treatment of transfected CV-1 cells demonstrated activation of the PPARalpha ligand-binding domain by MM-LDL, Ox-PAPC, or its component phospholipids, 1-palmitoyl-2-oxovalaroyl-sn-glycero-phosphocholine and 1-palmitoyl-2-glutaroyl-sn-glycero-phosphocholine; these lipids also activated a consensus peroxisome proliferator-activated receptor response element (PPRE) in transfected HAECs. Furthermore, activation of PPARalpha with synthetic ligand Wy14,643 stimulates the synthesis of IL-8 and MCP-1 by HAECs. By contrast, troglitazone, a PPARgamma agonist, decreased the levels of IL-8 and MCP-1. Finally, we demonstrate that unlike wild-type endothelial cells, endothelial cells derived from PPARalpha null mice do not produce MCP-1/JE in response to Ox-PAPC and MM-LDL. Together, these data demonstrate a proinflammatory role for PPARalpha in mediation of the activation of endothelial cells to produce monocyte chemotactic activity in response to oxidized phospholipids and lipoproteins.

Recurrence of meningiomas

BACKGROUND

Macroscopic total resection with removal of involved dura and bone does not always prevent the recurrence of meningioma of histologically benign subtype. Many causative factors have been investigated, although the mechanism of recurrence remains unclear. Vascular endothelial growth factor (VEGF) is a key factor in meningiomas neovascularization, and the authors investigated whether VEGF expression can predict the recurrence of histologically benign meningiomas after macroscopic total resection.

METHODS

Fifty-four patients with supratentorial convexity meningiomas were investigated at least 3 years after surgery or until tumor recurrence to clarify risk factors for recurrence. Patients were restricted to Simpson Grade 1 resection only, and the authors excluded multiple meningiomas, neurofibromatosis, and atypical and anaplastic meningiomas. Correlation between recurrence and the following factors were statistically analyzed: age, gender, tumor volume, tumor shape, bone change, brain edema, vascular supply, histologic subtype, MIB-1 labeling index (LI), and VEGF expression.

RESULTS

Of the 54 patients with meningioma, 34 were positive (24: +1; 10: +2) for VEGF, and 20 were negative. Six (11.1%) meningiomas recurred during the follow-up period. Multivariate analysis revealed that high levels of expression of VEGF constituted the most useful predictor of recurrence (P = 0.005), followed by high MIB-1 LI (P = 0.039). The other factors were not significant. The tumor recurrence, when it occurred, was within the brain and not durally based.

CONCLUSIONS

The current results suggest that high levels of VEGF expression are significantly related to the recurrence of meningioma. VEGF secretion from microscopic residue remaining after surgery may induce neovascularization, which promotes the recurrence of meningioma.

Absence of mutations in the NBS1 gene in B-cell malignant lymphoma patients

BACKGROUND

Nijmegen breakage syndrome (NBS), also known as ataxia-telangiectasia (AT) variant, is an autosomal recessive disorder characterized by microcephaly, growth retardation, severe combined immunodeficiency and a high incidence of lymphoid carcinoma, the majority of which are B-cell lymphomas. To determine whether the NBS1 gene is a tumor suppressor gene in B-cell lymphoma, we screened B-cell malignant lymphoma (ML) for any evidence of NBS1 mutation.

MATERIALS AND METHODS

Sequence analysis of the NBS1 gene was performed from PCR products amplified from the DNA of 12 extracranial ML or RT-PCR products amplified from cDNA of 8 primary central nervous system lymphoma.

RESULTS

Direct sequence analysis revealed that no NBS1 mutations were present in any of these patients.

CONCLUSION

The present results suggested that the contribution of NBS1 mutations to B-cell ML was minimal, despite the fact that the NBS1 gene was causative factor in these cases.

Size-adjustable titanium plate for reconstruction of the sella turcica. Technical note

A size-adjustable plate constructed of pure titanium is proposed for use in the reconstruction of the sella turcica. The plate is composed of two semicircular pieces that are connected by a hinge located at the top of the plate. Using an applicator, the plate is inserted into the sella turcica in a closed position. The same applicator is then used to open and secure the plate. The titanium causes minimal ferromagnetic artifacts on postoperative magnetic resonance imaging. Preliminary findings indicate a possible clinical use for this plate in the reconstruction of the sella turcica when no suitable piece of bone is available.

All ApoB-containing lipoproteins induce monocyte chemotaxis and adhesion when minimally modified. Modulation of lipoprotein bioactivity by platelet-activating factor acetylhydrolase

Mildly oxidized LDL has many proinflammatory properties, including the stimulation of monocyte chemotaxis and adhesion, that are important in the development of atherosclerosis. Although ApoB-containing lipoproteins other than LDL may enter the artery wall and undergo oxidation, very little is known regarding their proinflammatory potential. LDL, IDL, VLDL, postprandial remnant particles, and chylomicrons were mildly oxidized by fibroblasts overexpressing 15-lipoxygenase (15-LO) and tested for their ability to stimulate monocyte chemotaxis and adhesion to endothelial cells. When conditioned on 15-LO cells, LDL, IDL, but not VLDL increased monocyte chemotaxis and adhesion approximately 4-fold. Chylomicrons and postprandial remnant particles were also bioactive. Although chylomicrons had a high 18:1/18:2 ratio, similar to that of VLDL, and should presumably be less susceptible to oxidation, they contained (in contrast to VLDL) essentially no platelet-activating factor acetylhydrolase (PAF-AH) activity. Because PAF-AH activity of lipoproteins may be reduced in vivo by oxidation or glycation, LDL, IDL, and VLDL were treated in vitro to reduce PAF-AH activity and then conditioned on 15-lipoxygenase cells. All 3 PAF-AH-depleted lipoproteins, including VLDL, exhibited increased stimulation of monocyte chemotaxis and adhesion. In a similar manner, lipoproteins from Japanese subjects with a deficiency of plasma PAF-AH activity were also markedly more bioactive, and stimulated monocyte adhesion nearly 2-fold compared with lipoproteins from Japanese control subjects with normal plasma PAF-AH. For each lipoprotein, bioactivity resided in the lipid fraction and monocyte adhesion could be blocked by PAF-receptor antagonists. These data suggest that the susceptibility of plasma lipoproteins to develop proinflammatory activity is in part related to their 18:1/18:2 ratio and PAF-AH activity, and that bioactive phospholipids similar to PAF are generated during oxidation of each lipoprotein. Moreover, LDL, IDL, postprandial remnant particles, and chylomicrons and PAF-AH-depleted VLDL all give rise to proinflammatory lipids when mildly oxidized.

Peritumoral brain edema associated with meningioma: influence of vascular endothelial growth factor expression and vascular blood supply

BACKGROUND

The extent of peritumoral brain edema (PTBE) associated with meningiomas is very variable. Many causative factors have been investigated, but the mechanism of PTBE associated with meningioma has been unclear until now. Recently, the cerebral-pial blood supply and vascular endothelial growth factor (VEGF) have been implicated as causative factors of PTBE.

METHODS

Seventy-three supratentorial meningiomas were investigated to identify factors, including type of arterial blood supply and VEGF expression, that may influence the development of meningioma-associated PTBE. The type of arterial blood supply was defined by the selective angiography. Paraffin embedded tumor sections were stained with monoclonal VEGF antibody by an immunoperoxidase method. The extent of PTBE was estimated by using preoperative magnetic resonance imaging as an edema index (EI).

RESULTS

Forty-six meningiomas demonstrated PTBE, and the other 27 did not. Multiple regression analysis revealed close correlation between PTBE and type of arterial supply (P = 0.004), size of tumor (P = 0.021), vascular density (P = 0.028), and VEGF expression (P = 0.046). In meningiomas with cerebral-pial supply, the EI had increased significantly, just as VEGF was strongly expressed (P < 0.001). In contrast, meningiomas without a cerebral-pial supply developed little or no PTBE and less VEGF expression.

CONCLUSIONS

The current results suggest that VEGF expression contributes to PTBE formation in meningioma only when a cerebral-pial blood supply exists.

Symptomatic Rathke's cleft cyst coexisting with central diabetes insipidus and hypophysitis: case report

We describe a 48-year-old female with acute onset of central diabetes insipidus followed by mild anterior pituitary dysfunction. Magnetic resonance imaging (MRI) revealed enlargement of the hypophysis-infundibulum accompanied by a cystic component. She underwent a transsphenoidal exploration of the sella turcica. Histological examination showed foreign body type xanthogranulomatous inflammation in the neurohypophysis which might have been caused by rupture of a Rathke's cleft cyst. The MRI abnormalities and anterior pituitary dysfunction improved after a short course of corticosteroid administration, but the diabetes insipidus persisted. The histological findings in this case indicated the site of RCC rupture and the direction of the progression of RCC induced neurohypophysitis and adenohypophysitis.

[A case of cerebral juvenile pilocytic astrocytoma: observation of the development of the tumor]

A case with cerebral juvenile pilocytic astrocytoma (JPA) was reported. The patient was 33-month-old boy, who developed headache and loss of activity on December, 1994. Although he was indicated macrocephaly at the age of just 1 year, CT scan showed no abnormality at that time. On admission, MRI revealed multiple large cysts with an enhanced mural nodule in the left frontal lobe. The tumor was totally removed, and histologically diagnosed as JPA, because of alternating two types of structures of loose knit tissue composed of satellite astrocytes and compact tissue consisting of highly fibrillate cells. MIB-1 percent positivity was almost negative. We summarized and discussed the clinicopathological and proliferating characteristics of the cerebral JPA. These considerations suggested that the tumor already existed at the age of 1 year and developed during these 20 months, according to the theory that the growth rate of JPAs is programmed to slow down as the patient grows.

Transformation of rat glioma cells with the M-CSF gene inhibits tumorigenesis in vivo

Macrophage colony-stimulating factor (M-CSF) is a potent stimulator of the effector cells such as monocytes and macrophages. To evaluate the effect of M-CSF on malignant gliomas, we transfected the rat gliosarcoma cell line (9L) with human M-CSF expression vector (pCEF-MCSF) by a liposome method. Transfectants were selected using G418-containing medium. As a control, 9L cells transfected with pRc/CMV and selected by G418 were used. The effects of M-CSF gene transfection on tumor cell proliferation in vitro and in vivo were examined. All growth rate did not change in vitro. While the control 9L cells formed progressively enlarging masses, 9L cells transfected with the M-CSF gene did not develop into tumors after the injection into rats. On the other hand, in rats receiving anti-asialo GM1 antibody, 9L cells transfected with M-CSF gene developed into tumors, though at a slower rate than control 9L cells. Histologic examination after transplantation of 9L cells transfected with M-CSF gene disclosed intense infiltration of macrophages in the tumor. Thus M-CSF gene transfection into glioma cells stimulates an antitumor effect.

High concentrations of recombinant adenovirus expressing p16 gene induces apoptosis in lung cancer cell lines

In this study, we discussed the effects of treatment with recombinant adenovirus expressing p16 (AX-p16) on cell growth and cell death. Ax-p16 at 10 m.o.i. groups showed growth inhibition 3 days after gene transfection, but the cells regrew and did not undergo cell death. On the other hand, Ax-p16 at 300 m.o.i. groups showed complete cell growth inhibition leading to cell death which was apparent 7 days after p16 gene transfection. In the high m.o.i. Ax-mock groups, cell death was marked just after infection, but had diminished by 7 days after infection. Downregulation of pRB was detected only in Ax-p16 at 300 m.o.i. groups. These data suggest that a) high m.o.i. condition of Ax-p16 gives therapeutic benefits due to the combined effects of adenovirus and high expression of p16; and b) the cell killing mechanism of the p16 transgene is different from that of high m.o.i. adenoviral infection.

Mice lacking serum paraoxonase are susceptible to organophosphate toxicity and atherosclerosis

Serum paraoxonase (PON1) is an esterase that is associated with high-density lipoproteins (HDLs) in the plasma; it is involved in the detoxification of organophosphate insecticides such as parathion and chlorpyrifos. PON1 may also confer protection against coronary artery disease by destroying pro-inflammatory oxidized lipids present in oxidized low-density lipoproteins (LDLs). To study the role of PON1 in vivo, we created PON1-knockout mice by gene targeting. Compared with their wild-type littermates, PON1-deficient mice were extremely sensitive to the toxic effects of chlorpyrifos oxon, the activated form of chlorpyrifos, and were more sensitive to chlorpyrifos itself. HDLs isolated from PON1-deficient mice were unable to prevent LDL oxidation in a co-cultured cell model of the artery wall, and both HDLs and LDLs isolated from PON1-knockout mice were more susceptible to oxidation by co-cultured cells than the lipoproteins from wild-type littermates. When fed on a high-fat, high-cholesterol diet, PON1-null mice were more susceptible to atherosclerosis than their wild-type littermates.

Adenovirus-mediated p16 gene transfer prevents drug-induced cell death through G1 arrest in human glioma cells

This study examined the effects of full-length p16 gene transfer by recombinant adenovirus on cell growth and on sensitivity to CDDP or ACNU chemotherapies. We developed a recombinant adenovirus expressing the full-length human p16 gene (AxCA-hp16) by the COS-TPC method. AxCA-hp16 was infected into the p16-null human glioma cell line, U251MG. AxCA-hp16 infection inhibited proliferation of U251MG cells. A proliferation assay employing MTT showed that AxCA-hp16 infection induced chemoresistance, preventing CDDP-induced cell death (11- to 15-fold) and ACNU-induced cell death (80- to 92-fold). In the absence of AxCA-hp16, cell death was induced with CDDP or ACNU at 3 to 5 days after treatment, as demonstrated by Trypan-blue exclusion. Flow-cytometric analysis showed that CDDP or ACNU arrested cells in the G2 phase on day 1 and that cells re-entered the cycle on day 3. However, the cells infected with AxCA-hp16 after CDDP or ACNU treatment showed G1 arrest on day 5 after re-entering the cycle from G2 arrest on day 3. The cells infected with AxCA-hp16 before CDDP or ACNU treatment showed G1 arrest over the 5 days after the infection. This study demonstrated that G1 arrest induced with p16-gene expression prevents ACNU- or CDDP-induced cell death. The cell death induced by ACNU and CDDP therefore appears to occur in the phase after the G1/S check point.

Amyloid-beta induces chemokine secretion and monocyte migration across a human blood--brain barrier model

BACKGROUND

Aside from numerous parenchymal and vascular deposits of amyloid beta (A beta) peptide, neurofibrillary tangles, and neuronal and synaptic loss, the neuropathology of Alzheimer's disease is accompanied by a subtle and chronic inflammatory reaction that manifests itself as microglial activation. However, in Alzheimer's disease, alterations in the permeability of the blood-brain barrier and chemotaxis, in part mediated by chemokines and cytokines, may permit the recruitment and transendothelial passage of peripheral cells into the brain parenchyma.

MATERIALS AND METHODS

Human monocytes from different donors were tested for their capacity to differentiate into macrophages and their ability to secrete cytokines and chemokines in the presence of A beta 1-42. A paradigm of the blood-brain barrier was constructed utilizing human brain endothelial and astroglial cells with the anatomical and physiological characteristics observed in vivo. This model was used to test the ability of monocytes/macrophages to transmigrate when challenged by A beta 1-42 on the brain side of the blood-brain barrier model.

RESULTS

In cultures of peripheral monocytes, A beta 1-42 induced the secretion of proinflammatory cytokines TNF-alpha, IL-6, IL-1 beta, and IL-12, as well as CC chemokines MCP-1, MIP-1 alpha, and MIP-1 beta, and CXC chemokine IL-8 in a dose-related fashion. In the blood-brain barrier model, A beta 1-42 and monocytes on the brain side potentiated monocyte transmigration from the blood side to the brain side. A beta 1-42 stimulated differentiation of monocytes into adherent macrophages in a dose-related fashion. The magnitude of these proinflammatory effects of A beta 1-42 varied dramatically with monocytes from different donors.

CONCLUSION

In some individuals, circulating monocytes/macrophages, when recruited by chemokines produced by activated microglia and macrophages, could add to the inflammatory destruction of the brain in Alzheimer's disease.

Genetic immunotherapy by intrapleural, intraperitoneal and subcutaneous injection of IL-2 gene-modified Lewis lung carcinoma cells

The induction and augmentation of tumor non-specific immunity and of tumor-specific immunity by intrapleural, intraperitoneal and subcutaneous injection of interleukin-2 (IL-2) gene-modified Lewis lung carcinoma (LLC) cells (LLC-IL2) was tested in C57BL/6 mice. Intrapleural injection of LLC cells induced lung tumors with a malignant effusion, intraperitoneal injection induced peritoneal tumors with ascites and subcutaneous injection induced subcutaneous tumors. Intrapleural injection of irradiated LLC-IL2 cured pre-existing lung LLC tumors and extended the survival of the mice but did not affect survival of mice with pre-existing peritoneal tumors nor did it affect the growth of s.c. tumors. Intraperitoneal injection of irradiated LLC-IL2 cured pre-existing LLC peritoneal tumors and extended the survival of the mice but did not affect survival of mice bearing lung tumors nor did it affect the growth of s.c. tumors. Subcutaneous injection of irradiated LLC-IL2 did not affect the growth of preexisting s.c. tumors and also did not improve survival of mice bearing the lung or peritoneal tumors. Injection with irradiated LLC-IL2 by all routes, i.e., intrapleural, intraperitoneal and s.c., protected against subsequent re-challenge with LLC. Eight days after the initial immunization (early stage of immunization), non-adherent mononuclear cells in the peritoneal cavity of the mice treated with intraperitoneal injection of irradiated LLC-IL2 displayed enhanced cytotoxicity against LLC, B16-F10 and P815 cells, while the cytotoxic activity of spleen cells in the same mice did not change. The efficiency of induction of tumor-specific immunity was the strongest after intraperitoneal immunization and weakest after s.c. immunization. In vitro analysis using the spleen cells of mice immunized with irradiated LLC-IL2 suggested that CD8+ T cells play a key role in tumor-specific immunity.

Genetic immunotherapy by intrapleural, intraperitoneal and subcutaneous injection of IL-2 gene-modified Lewis lung carcinoma cells

The induction and augmentation of tumor non-specific immunity and of tumor-specific immunity by intrapleural, intraperitoneal and subcutaneous injection of interleukin-2 (IL-2) gene-modified Lewis lung carcinoma (LLC) cells (LLC-IL2) was tested in C57BL/6 mice. Intrapleural injection of LLC cells induced lung tumors with a malignant effusion, intraperitoneal injection induced peritoneal tumors with ascites and subcutaneous injection induced subcutaneous tumors. Intrapleural injection of irradiated LLC-IL2 cured pre-existing lung LLC tumors and extended the survival of the mice but did not affect survival of mice with pre-existing peritoneal tumors nor did it affect the growth of s.c. tumors. Intraperitoneal injection of irradiated LLC-IL2 cured pre-existing LLC peritoneal tumors and extended the survival of the mice but did not affect survival of mice bearing lung tumors nor did it affect the growth of s.c. tumors. Subcutaneous injection of irradiated LLC-IL2 did not affect the growth of preexisting s.c. tumors and also did not improve survival of mice bearing the lung or peritoneal tumors. Injection with irradiated LLC-IL2 by all routes, i.e., intrapleural, intraperitoneal and s.c., protected against subsequent re-challenge with LLC. Eight days after the initial immunization (early stage of immunization), non-adherent mononuclear cells in the peritoneal cavity of the mice treated with intraperitoneal injection of irradiated LLC-IL2 displayed enhanced cytotoxicity against LLC, B16-F10 and P815 cells, while the cytotoxic activity of spleen cells in the same mice did not change. The efficiency of induction of tumor-specific immunity was the strongest after intraperitoneal immunization and weakest after s.c. immunization. In vitro analysis using the spleen cells of mice immunized with irradiated LLC-IL2 suggested that CD8+ T cells play a key role in tumor-specific immunity.

Transformation of human glioma cell lines with the p16 gene inhibits cell proliferation

We examined the genomic status of the p16 gene in 5 human glioma cell lines by Southern blot analysis. The p16 gene was located in the 9p21 chromosomal region and homozygous deletion was detected in 4 of 5 (80%) human glioma cell lines and 5 of 15 (33%) clinical samples. We transfected the full-length human p16 gene into p16-null human glioma cell line, U251MG cells, using the plasmid vector pRc/CMV-p16 and evaluated the effect of p16 gene transfer on the growth suppression of malignant glioma cells. The transfection of p16 cDNA caused growth suppression through G1 cell cycle arrest in U251MG cells. We also examined the effect of p16 gene transfer on the chemosensitivity to cis-diamminedichloroplatinum II (CDDP), 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl) -3-nitrosourea hydrochloride (ACNU), and 5'-azacytidine (AZC). We did not detect any change in them after p16 gene transfer. These results might suggest that deletion of p16 genes promoted unrestrained growth in human glioma but has no relationship to the chemosensitivity to CDDP, ACNU and AZC.

[Cyclosporine as drug resistance modifiers; mechanism and clinical investigation]

Multidrug resistance(MDR), mediated by P-glycoprotein, is a well-understood mechanism of resistance to anticancer drugs. P-glycoprotein is thought to act as an efflux pump with broad specificity for variety of anticancer drugs. Cyclosporine and its analogue, SDZ PSC 833, have demonstrated ability to inhibit P-glycoprotein mediated transport function, restore accumulation defects for anticancer drugs, and reverse resistance in vitro and in vivo. The clinical trials of these drugs are on going. P-glycoprotein may also play a pivotal role in the evolution of pharmacological defence mechanisms, protecting organisms from cytotoxic agents. Approach to overcome resistance may result in serious challenges to the host's natural defenses. Clinical trials of MDR modulators, such as cyclosporine or SDZ PSC 833, should be designed with caution and with careful consideration for potential pharmacokinetic and pharmacodynamic interaction.

Parasellar chronic inflammatory disease presenting Tolosa-Hunt syndrome, hypopituitarism and diabetes insipidus: a case report

We describe a 60-year-old man with a history of Tolosa-Hunt syndrome associated with intermittent painful ophthalmoplegia and a visual disturbance on the left side, who presented with signs and symptoms of severe hypoadrenalism and diabetes insipidus. Magnetic resonance imaging demonstrated enlargement of the hypophysis and infundibulum and left cavernous sinus. An endocrinologic study revealed anterior pituitary dysfunction and diabetes insipidus. The patient underwent a transsphenoidal biopsy which revealed chronic inflammation in the hypophysis, mucosa of the sphenoid sinus, and dura mater. The patient was treated with steroids that decreased the size of the hypophysis and infundibulum, but the symptoms of anterior pituitary insufficiency and diabetes insipidus have persisted. The chronic inflammation of the hypophysis and infundibulum is thought to have spread from the cavernous sinus.

Genetic-dietary regulation of serum paraoxonase expression and its role in atherogenesis in a mouse model

In an effort to identify genetic factors contributing to atherogenesis, we have studied inbred strains of mice that are susceptible (C57BL/6J) and resistant (C3H/HeJ) to diet-induced aortic fatty streak lesions. When maintained on a low-fat diet, HDL isolated from both strain C57BL/6J (B6) and C3H/HeJ (C3H) mice protect against LDL oxidation in a coculture model of the artery wall. However, when maintained on an atherogenic diet high in fat and cholesterol, the HDL isolated from B6 mice lose the capacity to protect, whereas HDL from C3H mice protect equally well. Associated with the loss in the ability of HDL to protect is a decrease in the activity of serum paraoxonase, a serum esterase carried on HDL that has previously been shown to protect against LDL oxidation in vitro. The levels of paraoxonase mRNA decreased in B6 mice upon challenge with the atherogenic diet but increased in C3H, indicating that paraoxonase production is under genetic control. In a set of recombinant inbred strains derived from the B6 and C3H parental strains, low paraoxonase mRNA levels segregated with aortic lesion development, supporting a role for paraoxonase in atherogenesis.

Non-insulin-dependent diabetes mellitus complicated with idiopathic hypoparathyroidism

We report a case of non-insulin-dependent diabetes mellitus (NIDDM) complicated with idiopathic hypoparathyroidism. A 74-year-old male was hospitalized because of diplopia. He was revealed to have NIDDM. The levels of serum Ca and intact-PTH were 6.3 mg/dl and < 5 pg/ml, respectively. Brain computed tomography revealed abnormal calcification in the cerebral basal ganglia and the cerebellum. After recovery from hypocalcemia, the endogenous insulin secretion was normalized. It is suggested that the pathogenesis of NIDDM in this patient may have been related to an insulin secretory defect as a result of hypocalcemia in addition to the hereditary risk.

Evaluation of cerebral blood flow in patients with idiopathic orthostatic hypotension using Tc-99m HMPAO brain SPECT during postural testing

To determine whether regional cerebral blood flow (rCBF) would change on standing in patients with idiopathic orthostatic hypotension (IOH), Tc-99m HMPAO SPECT studies were performed during postural testing in five patients with IOH. After 10 minutes of quiet rest on a bed, the patients arose quickly and, at the same time, the radiotracer was injected intravenously. SPECT data were obtained with a ring-type SPECT scanner. Another dose of Tc-99m HMPAO was injected with the subjects in the supine position, and SPECT was performed again. Image subtraction was used to evaluate the change in rCBF caused by postural testing. In all patients, the authors observed a decrease of rCBF ni the frontal cortex and basal ganglia. This preliminary study suggests that changes in rCBF occur in patients with IOH on standing, and Tc-99m HMPAO SPECT performed during postural testing may have an important role in evaluating these changes.

Lipid-induced changes in intracellular iron homeostasis in vitro and in vivo

Iron promotes cellular damage via its capacity to catalyze hydroxyl radical formation and by peroxidation of unsaturated lipids. The major cellular iron storage depot, ferritin, acts as a critical antioxidant defense by sequestering unbound or "free" iron, limiting its participation in damaging oxidative reactions. In this study, we investigated the relationship between LDL modified by artery wall cells and the regulation of intracellular free iron levels in the mouse model and in a human aortic endothelial and smooth muscle cell coculture system. We found in response to an atherogenic diet, fatty streak-resistant C3H/HeJ mice exhibited higher levels of liver apoferritin and lower intracellular concentrations of free iron than did fatty streak-susceptible C57 BL/6J mice. Also, ferritin repressor protein mRNA was not significantly suppressed after 15 wk on the atherogenic diet in female C57BL/6J mice, which exhibit the most extensive fatty streak formation, but was significantly reduced in C3H/HeJ mice. Iron loading of coculture cells resulted in elevations of cellular free iron and enhanced LDL-induced monocyte transmigration. Pretreatment of cells with apoferritin completely abolished iron-induced LDL modification. Addition of LDL to cocultures resulted in elevations in lipid peroxidation products, intracellular free iron, apoferritin mRNA expression, and apoferritin synthesis, suggesting a possible relationship between the oxidative modification of LDL and iron metabolism.