Progressive degeneration of articular cartilage and intervertebral discs. An experimental study in transgenic mice bearing a type IX collagen mutation

Transgenic mice expressing mutant alpha 1(IX) collagen were produced and found to develop progressive joint degeneration with age, as well as accelerated intervertebral disc degeneration. Radiological and histological studies showed that cervical and lumbar disc degeneration was more advanced in the transgenic mice than in control litter-mates. The changes included shrinkage or disappearance of the nucleus pulposus, and fissures in the annulus fibrosus which sometimes lead to herniation of disc material and slight osteophyte formation. These findings suggest that mutations of the type IX collagen may cause certain forms of degenerative disease in the spine as well as in joints.

Asp-285 of the metal-tetracycline/H+ antiporter of Escherichia coli is essential for substrate binding

The transposon Tn10-encoded metal-tetracycline/H+ antiporter (TetA(B)) was preferentially photolabeled when [3H]tetracycline was irradiated in the presence of energized inverted membrane vesicles containing the TetA protein. The degree of labeling depended on the duration of irradiation and the energization of the membrane. Photolabeling was not observed in vesicles containing the Asp-285 --> Asn mutant TetA protein, indicating that Asp-285 participates in the substrate binding or the step(s) prior to substrate binding.

Effect of polyol fatty acid esters on diclofenac permeation through rat skin

The effects of a series of polyol fatty acid esters (sefsols) on diclofenac permeation through rat skin were investigated using in vitro and in vivo methods. Four monoesters and one diester of sefsol were selected as a vehicle components. The effects of each sefsol on in vitro diclofenac permeation were compared at a concentration of 5% sefsol in water. Monoesters of sefsol, except the glyceryl monoester, enhanced the percutaneous permeation of diclofenac. The highest enhancement was observed in propylene glycol monocaprylate. The plasma concentration of diclofenac was increased dramatically by the addition of 10% propylene glycol monocaprylate when applying the diclofenac sodium suspension to abdominal rat skin in vivo. These results suggest that the monoesters of polyol fatty acid are potential candidates to enhance the transdermal absorption of diclofenac sodium.

Oral administration of insulin as poly(vinyl alcohol)-gel spheres in diabetic rats

The oral administration of insulin in poly(vinyl alcohol)-gel spheres (PVA-GS), an oral dosage form with prolonged residence time in the ileum, was examined in streptozotocin-induced diabetic rats. Intragastric administration of PVA-GS containing insulin and a protease inhibitor, aprotinin or bacitracin, caused a significant and prolonged reduction of blood glucose levels, suggesting insulin absorption. The bioavailability of insulin estimated from the hypoglycemic effect was about 2% in the presence of either protease inhibitor. The release profiles of insulin and the protease inhibitors from the PVA-GS could be explained by Higuchi's plot, and the rates were similar to each other. The site dependency of insulin absorption in the intestinal tract was examined by an in situ loop method. Insulin absorption estimated by plasma insulin levels was larger in the ileum and the large intestine than in the jejunum. The prolonged residence time of PVA-GS in the absorption site, the lower intestine, and the synchronous release of insulin and the protease inhibitors from the PVA-GS are the two major explanations for the improved bioavailability of insulin administered as PVA-GS containing a protease inhibitor.

[A case of aortic dissection associated with congenital bicuspid aortic valve]

It is known that bicuspid aortic valve with dilatation of the ascending aorta is one of risk factors of the aortic dissection. A case of acute aortic dissection (DeBakey type-II) associated with bicuspid aortic valve who underwent successfully operation 8 hours after onset is reported. This patient went into cardiogenic shock because of cardiac tamponade and aortic valve regurgitation immediately after onset. Aortic valve and the ascending aorta were replaced using composite graft (#23 SJM prosthetic aortic valve and 26 mm woven Dacron vascular graft) combined with coronary artery reconstruction by Cabrol's technique. Aortic valve showed bicuspid and histological examination revealed cystic medionecrosis and loss of elastic fiber. Postoperative course was uneventful and this patients is doing well 3 years after the operation.

Large neurons in the tuberomammillary nucleus in patients with Parkinson's disease and multiple system atrophy

To investigate whether the histaminergic neurons degenerate in Parkinson's disease (PD) and multiple system atrophy (MSA), we studied the number of large-sized neurons in the tuberomammillary nucleus in patients with PD, patients with MSA, and age-matched controls. The number of large-sized neurons in the tuberomammillary nucleus in PD patients was not altered compared with controls, and Lewy bodies were rarely present in the tuberomammillary nucleus. In contrast, the number of large-sized neurons in the tuberomammillary nucleus in MSA patients was significantly decreased compared with controls. Thus, the central histaminergic neurons are affected in MSA and preserved in PD.

Oxidative folding of omega-conotoxin MVIIC: effects of temperature and salt

Oxidative folding of omega-conotoxin MVIIC, a highly basic 26-amino acid peptide with three disulfide bonds, predominantly gave two products with mismatched disulfide bonds in 0.1M NH4OAc buffer (pH 7.7) at 21 degrees C both in the presence and absence of redox reagents such as reduced and oxidized glutathione. A low reaction temperature (5 degrees C) and a high salt concentration in buffer such as 2M (NH4)2SO4 were necessary to obtain the correctly folded biologically active product. The folding reaction was found to proceed via a two-stage pathway of (I) the formation and (II) the rearrangement of the mismatched disulfide bonds. Both the reaction temperature and the salt strongly affected the equilibrium between mismatched and correctly formed disulfide bonds in the second stage. Such an effect of salts on the rearrangement reaction could be explained by anion binding at a low concentration and the salting out effect at a high concentration by analyzing the rank order of their effectiveness. The anion-binding effect was also confirmed by examining the folding of the tetra-acetylated peptide at the Lys side chains. CD study suggested that the yield of the biologically active product was correlated with its conformational change as functions of temperature and salt concentration.

Pharmacokinetics of glycyrrhizin in rats with D-galactosamine-induced hepatic disease

The pharmacokinetic behavior of glycyrrhizin (GZ) was examined in D-galactosamine-intoxicated (GAL) rats. When GZ was administered intravenously, the apparent volume of distribution (Vdss) and the total body clearance (CLtotal) were more significantly decreased in GAL rats than those in normal rats. When GZ was administered orally, the area under the plasma concentration-time curve (AUC), the mean residence time (MRT) and the time to reach the maximum plasma concentration (Tmax) for GZ were higher, but the maximum plasma concentration (Cpmax) in GAL rats was lower than that in normal rats. The bioavailability of GZ, however, was not significantly changed. On the other hand, the AUC for glycyrrhetic acid (GA), a main metabolite of GZ, after oral administration of GZ was higher in GAL rats than in normal rats, although there was no significant difference in MRT or Tmax, Cpmax or the bioavailability for GA between GAL and normal rats. The reasons for these differences in GAL rats would be changes in the absorption rate (reduced gastric emptying rate) and reduction of the hepatic elimination rates (biliary excretion of GZ and hepatic metabolism of GA).

Enzyme-linked immunoassay for midkine, and its application to evaluation of midkine levels in developing mouse brain and sera from patients with hepatocellular carcinomas

Midkine (MK) is a growth factor that promotes neurite outgrowth and survival of neurons, and enhances the plasminogen activator in endothelial cells. A highly sensitive enzyme-linked immunoassay for MK was developed, involving affinity-purified anti-MK antibodies, their biotinylated form, and avidin-beta-galactosidase. The amount of bound avidin-beta-galactosidase was determined using a fluorogenic substrate, 4-methylumbelliferyl-beta-D-galactoside. This method allowed the detection of human and mouse MK in the range of 50 pg-10 ng. Pleiotrophin, which is related to MK in its amino acid sequence, did not show any cross reactivity. Employing this method, the MK levels in the developing mouse brain were determined. The MK level was 2 micrograms/g of wet tissue on the 12th day of gestation, and then steadily decreased during embryogenesis and postnatal development to 30 ng/g two months after birth. The assay method can also be applied to serum samples. Although the MK levels in the sera of normal human subjects were low or undetectable, 0.6-8 ng/ml of MK was detected in samples in the majority of cases of hepatocellular carcinomas.

[Cytomegalovirus fetal infection. Porencephaly with polymicrogyria in a 15-year-old boy]

A boy, born after 41 weeks of gestation, presented with splenomegaly, microcephaly and chorioretinitis accompanied by immaturity signs. His mother was in good health but her previous pregnancy had been aborted owing to rubella. Laboratory data, including serological and virological evidence, confirmed the diagnosis of fetal cytomegalovirus infection. CT scan indicated a large cyst in the left temporal lobe and periventricular calcifications. At about 8 months of age, convulsions were noticed which were not controlled effectively by medication. There was spastic rigidity without significant psychomotor development. He died at the age of 15. Postmortem neuropathological examination revealed polymicrogyria predominant in the right cerebral hemisphere as well as a large cavity in the left temporal lobe communicating with the lateral ventricle. Widespread heterotopias and calcifications were observed notably in the periventricular white matter. No typical inclusion was found. By the method of Holzer and GFAP immunocytochemistry, no gliosis was noted in the cerebral cortex having the feature of polymicrogyria. This might support the theory that polymicrogyria is caused by neuronal migration failure.

Immunohistochemical examination of phosphorylated tau in granulovacuolar degeneration granules

Granulovacuolar degeneration (GVD) and neurofibrillary tangles (NFT) are neuropathological features in Alzheimer's disease (AD). The molecular mechanism of GVD formation remains unknown. Recent immunohistochemical investigations suggested a potential link of NFT to GVD formation. Enzyme histochemical studies and electronmicroscopic findings suggested that GVD is formed through lysosomal autophagy of intraneuronal substances. We recently demonstrated that in non-demented cases NFT was phosphorylated at serines 199, 202 and 422 in paired helical filament (PHF)-tau more than in serine 396, while NFT in AD cases was similarly phosphorylated at these four sites in tau. In this study, we demonstrated immunohistochemically a similar phosphorylation state of tau in GVD granules to that in NFT in both non-demented cases and AD patients by using a mouse monoclonal anti-tau antibody and three phosphorylation site-specific antibodies for PHF-tau, indicating that GVD granules and NFT are composed of similar phosphorylated-tau. However, we could not detect PHF structures within any GVD using electronmicroscopy, indicating that PHF itself is not phagocytized by lysosomes during GVD formation. Therefore, the source of GVD granules might be phosphorylated pre-PHF-tau.

Prenatal diagnosis of Duchenne muscular dystrophy using a single fetal nucleated erythrocyte in maternal blood

We developed a method that allows prenatal diagnosis of Duchenne muscular dystrophy using a single nucleated erythrocyte (NRBC) isolated from maternal blood. Maternal blood was obtained at 8 to 20 weeks of gestation. NRBCs were separated with Percoll using a discontinuous density gradient method and then collected by micromanipulator under microscopic observation. The entire genome of a single cell was amplified by primer extension preamplification (PEP). Sex was determined from a small aliquot of the PEP reaction. After an NRBC was determined to be male and confirmed to be of fetal origin, dystrophin exons 4, 8, 12, 45, 48, 50, and 51 were determined from the same PEP reaction. This diagnostic method using maternal blood is safer than amniocentesis or cordocentesis and can be applied to other X-linked diseases.

[Ultrasonographic diagnosis of breast cancer with intraductal spreading of cancer cells]

The estimation of intraductal lesions of the breast has become possible due to the careful examination of ultrasonic ductal images. The diagnostic accuracy ratio of the lesions was 94.4% by using our classification of dilated ducts by ultrasonography. The characteristics of the findings of intraductal spreading of breast cancer are that the wall of the duct is thick and uneven because of the proliferation of cancer cells, the tumor usually has a broad base all along the walls, and, when the duct is filed with cancer cells, the circumference becomes so varied that it appears outwardly irregular in size and shape. Microcalcifications and irregular nodules along the ductal network are also sometimes apparent. The diagnosis of the area of intraductal spreading of cancer cells could come about from examining the continuous spreading throughout the network by ultrasonography. We have succeedingly obtained successful results from using this method for the past eight years. The diagnostic accuracy ratio to determine the indication for breast conservative surgery and the extent of the breast excision was 94.2% in cases in which the tumor size was less than 3.0cm and the distance from the nipple was over 3.1cm, and in nonpalpable cases. In breast conservative surgery, the firm establishment of a proper diagnostic method is needed to prevent any cancerous tissue from being left. At this point in the evolution of the diagnostic method for intraductal spreading, ultrasonography is one of the key elements to achieve this goal. From now on, ultrasonography will be in the spotlight and take a more leading role in the continuing development of this diagnostic procedure.

Cortical laminar necrosis and central pontine myelinolysis in a patient with Sheehan syndrome and severe hyponatremia

Hypoxic encephalopathy and osmotic demyelination are independent clinical entities. We describe a rare case with these two complications as demonstrated by magnetic resonance imaging (MRI). A 58-year-old woman had adrenal crises twice a decade due to Sheehan syndrome. At the second crisis, hyponatremia was remarkable with consciousness disturbance which was rapidly corrected by intravenous administration of glucocorticoid and hypertonic saline. The maneuver improved consciousness disturbance, but resulted in hypokalemic ventricular fibrillation with circulatory failure. After the normalization of the circulation, however, her consciousness level deteriorated again. Repeated brain MRI revealed acute and chronic phases of cortical laminar necrosis and central pontine myelinolysis.

Meisenheimer rearrangement of azetopyridoindoles. VIII. Synthesis and antiviral activities of 12-carbaeudistomin analogs

Eudistomins, isolated from the colonial tunicate Eudistoma olivaceum, have been a synthetic target due to their strong antiviral activity against Herpes simplex virus (HSV-1) and activities against certain types of tumors in vivo. In order to examine the structure-activity relationship of eudistomins, 12-carbaeudistomin analogs were synthesized and their activities against influenza A and B virus, HSV-1, HSV-2 and human cytomegalovirus were investigated. Among them, racemic 6-methoxy-12-carbaeudistomin showed similar activity to (-)-debromoeudistomin K, synthesized as a control compound.

Alterations in spectral characteristics of heart rate variability as a correlate of cardiac autonomic dysfunction after esophagectomy or pulmonary resection

BACKGROUND

Both esophagectomy and pulmonary resection are associated with postoperative cardiac complications, partly because of autonomic perturbations involving the heart. This study was undertaken to determine whether heart rate variability (HRV), employed as an index of cardiac autonomic function, changes in patients undergoing esophagectomy or pulmonary resection.

METHODS

Electrocardiographic RR intervals were measured in 20 esophagectomized patients, 10 undergoing right and 10 undergoing left pulmonary resection on the preoperative day as baseline data and on postoperative days 1, 3, 5, 7, 14, and 30. Instantaneous heart rate was calculated every 250 ms from 416-s data of RR intervals. Power spectra of HRV for 128 s were computed using a fast Fourier transform and normalized by squared mean heart rate. The average ten sets of normalized HRV power were obtained by integrating the following power spectral bands: the low-, (0.06-0.10 Hz), high- (0.15-0.40 Hz), and total-frequency regions (0.01-0.40 Hz).

RESULTS

In the esophagectomy group, mean low-, high-, and total-frequency HRV power decreased after surgery to 17%, 6%, and 15% of their preoperative values, respectively, and these indexes remained suppressed for up to 30 days. After right pulmonary resection, low- and total-frequency HRV power decreased through 30 and 7 postoperative days, respectively. In the left pulmonary resection group, HRV remained unchanged. In the esophagectomy group, mean (+/- SEM) heart rate increased from 78 (+/- 3) bpm to more than 90 bpm throughout the study, and body temperature from 36.5 (+/- 0.1) degrees C to more than 37.0 degrees C through 14 postoperative days. Heart rate and body temperature remained increased for 3 days after pulmonary surgery. Mean arterial pressure remained unchanged in the three surgical groups.

CONCLUSIONS

Reductions indicate HRV after esophagectomy or right pulmonary resection indicate a substantial and prolonged surgical injury to the autonomic nervous control of pulse rate.

High-performance liquid chromatographic determination of lipoamidase (lipoyl-X hydrolase) activity with a novel substrate, lipoyl-6-aminoquinoline

An HPLC lipoamidase (lipoyl-X hydrolase) assay method has been developed, which uses a novel fluorescent substrate, lipoyl-6-aminoquinoline (LAQ). LAQ is synthesized from lipoic acid and 6-aminoquinoline (AQ) through lipoyl chloride as an intermediate and is conveniently purified by washing with chloroform-methanol. Mechanistic studies on the time-course, the dependence on enzyme and substrate concentrations were performed by using LAQ and a model enzyme (milk lipoamidase). Moreover, this method was successfully applied to the direct determination of the lipoamidase (LAQ hydrolase) activity in samples of human liver, milk, stools and porcine serum. Using this novel synthetic lipoyl substrate, we demonstrated that LAQ hydrolase was present in some specific tissues; LAQ hydrolase was solely present in the grey matter and not in the white matter in the human cerebrum. Furthermore, LAQ hydrolase activity was shown to increase in human liver cancer. Thus, this enzyme assay method is expected to be applicable to the tissue distribution study and also to the basic research on human diseases such as cancer.

Accumulation of advanced glycation end products of the Maillard reaction with age in human hippocampal neurons

The recent immunological demonstration of advanced glycation end products (AGE) of the Maillard reaction in several human tissues suggests a possible involvement of AGE in the aging process. We previously prepared a monoclonal anti-AGE antibody (6D12) which recognized N epsilon-(carboxymethyl)lysine. We examined, immunohistochemically, the effect of aging on AGE-immunoreactivity in hippocampal pyramidal neurons in ten brain tissue samples obtained at autopsy from subjects aged 20-85 years old. Using 6D12 antibody, our results demonstrated a positive correlation between AGE-immunoreactivity in hippocampal pyramidal neurons and age. A more intense immunoreaction was observed in the CA3-4 pyramidal neurons compared with that of the CA1 neurons, known to be vulnerable to the formation of neurofibrillary tangles. Our results suggest that AGE are probably involved in the aging process affecting the human central nervous system, and that AGE do not mainly contribute to the formation of neurofibrillary tangles, at least in the CA1 neurons.

His257 is a uniquely important histidine residue for tetracycline/H+ antiport function but not mandatory for full activity of the transposon Tn10-encoded metal-tetracycline/H+ antiporter

His257 is the only histidine residue located in the putative transmembrane region of the Tn10-encoded metal-tetracycline/H+ antiporter (TetA) and contributes to the substrate/H+ coupling [Yamaguchi, A.. Adachi, K., Akasaka. T., Ono. N., & Sawai, T. (1991) J. Biol. Chem. 266, 6045-6051]. Tn10-TetA contains five histidine residues, including His257. When these histidine residues were replaced by alanine one by one, only the His257Ala mutant showed almost complete loss of the tetracycline transport activity, whereas the other four His --> Ala mutants, H42A, H158A, H329A, and H359A, retained transport activity comparable to that of the wild type. The mutant which contains only one histidine, His257, retained about 80% of the wild-type activity, whereas the histidine-less mutant, in which all five histidine residues were replaced by Ala, exhibited little activity. These results clearly indicated that His257 is a unique histidine residue in TetA responsible for the transport activity. The His257Tyr mutant, irrespective of the presence or absence of the other four histidine residues, retained about 30% of the wild-type tetracycline transport activity and showed corresponding tetracycline-coupled H+ translocation, indicating that an imidazole group is not necessary at position 257 for the substrate/H+ coupling. A histidine-specific reagent, diethyl pyrocarbonate (DEPC), equally inactivated the wild-type and one-histidine mutant TetA, whereas the H257Y mutant was hardly inactivated by DEPC irrespective of the presence or absence of the other four histidine residues, indicating that the inactivation by DEPC is due to the modification of His257.