Circadian variation of urinary enzymes in the dog

Circadian variations of N-acetyl-beta-D-glucosamidase (NAG, EC 3.2.1.30) and gamma-glutamyl transpeptidase (gamma-GTP, EC 2.3.2.2) were examined in dogs. Urine and blood were collected at 4-hr intervals from adult mongrel dogs (11 males, 11 females) weighing between 7 and 13 kg. The collected urine and blood were used to measure creatinine, NAG and gamma-GTP. The amount of urine was significantly higher (p < 0.05) during the period from 12:00 to 16:00. Creatinine clearance did not show any characteristic variations and creatinine excretion was significantly higher (p < 0.05) during the period from 8:00 to 16:00. No characteristic variations were observed in the amounts excreted, activity, or NAG and gamma-GTP creatinine index. There were high correlations between creatinine excretion and creatinine clearance (r = 0.693), gamma-GTP excretion and gamma-GTP creatinine index (r = 0.724), NAG excretion and NAG creatinine index (r = 0.878), and between the NAG and gamma-GTP creatinine index of each 4-hr specimen and the NAG and gamma-GTP excretion of the 24-hr specimens. These results suggest the diagnostic usefulness measuring enzyme activity in non-periodically collected urine.

Selective and prolonged MRI enhancement by Mn-TPPS in an experimental rat brain tumour with peripheral benzodiazepine receptors

Synthesized Mn-TPPS, a paramagnetic metalloporphyrin, is expected to be a tumour specific contrast media for magnetic resonance (MR) imaging. We investigated the enhancing characteristics of Mn-TPPS using a transplanted rat C6 glioma model with peripheral type benzodiazepine (PBD) receptors since porphyrins are thought to possibly be endogenous ligands for PBD receptors. An Mn-TPPS enhancement study was then performed either with or without pretreatment while using peripheral and central type benzodiazepine receptor specific ligands (PK11195 and clonazepam, respectively). A signal intensity analysis disclosed the selective and prolonged enhancement of the brain tumour even at 17 h after the Mn-TPPS injection. This specific enhancement of the tumour, however, was not inhibited nor replaced by benzodiazepines. The tissue concentration of Mn-TPPS was significantly higher in the glioma tissue than the other tissues, while PK11195 pretreatment could not reduce the intratumoural Mn-TPPS concentration. A subcellular distribution study disclosed that Mn-TPPS was readily incorporated into the tumour cells. On the other hand, Mn-TPPS was not specifically distributed in the mitochondrial fraction where PBD receptors exist. The present study therefore indicates that Mn-TPPS could be incorporated into tumour cells and supports the potential use of this agent to improve the diagnostic specificity of MR imaging for brain tumours.

[A study on the fine mucosal pattern in the duodenal bulb]

To estimate the smallest unit of mucosa in the duodenal bulb radiologically, double contrast radiographs were investigated in correlation with endoscopy and histological examinations of biopsy specimens. Fine mucosal structures in the duodenal bulb were observed in 692 out of 1463 cases (47.4%) in double contrast radiographs in our upper gastrointestinal series from January, 1989 to December, 1990. Fine mucosal structures were subdivided into 3 categories: A; reticular and/or granular pattern (60.1%, 416/692), B; diffuse nodular pattern with or without additional A pattern (35.3%, 244/692), and C; diffuse tiny barium dots (4.6%, 32/692). Three pattern groups were reviewed by endoscopic and histological assessment of biopsy specimens in comparison with the control group of nonvisualized mucosal pattern (30 cases). Endoscopic observation was carried out in 170 out of 692 radiology cases in respect to irregularities in the duodenal mucosa (villous pattern, mucosal colour, nodule or depression, or disease) and associated diseases of the stomach. Fewer diseases (1 ulcer scar and 7 cases of the duodenitis, 15.6%) were visualized in the duodenal bulb than the stomach due to a prominent acid secretive function, which was confirmed by the Congo-Red method in groups A and B. A flat villi pattern was noted with accompanying disease in the duodenal bulb in 8 out of 11 cases of in group C (72.7%). By the Whitehead classification of duodenitis, 100% of group A, 98.5% of group B and 100% of group C revealed low grade inflammation (Grade < 2) in histological examinations of biopsy specimens (120 cases). The nodule seen in B pattern was histologically composed of nonspecific protruded mucosa (38%, 19/50), proliferation of lymphoid follicle (36%, 18/50), Brunner's gland hyperplasia (24%, 12/50) or heterotopic gastric mucosa (2%, 1/50). Consequently, mucosal patterns A, B and part of C might be appropriate as basic mucosal units of the normal duodenal bulb in double contrast radiograph.

A case report of surgical treatment of a dog with atrioventricular septal defect (incomplete form of endocardial cushion defect)

A 3-month-old female collie was diagnosed as having atrioventricular septal defect with ostium primum atrial septal defect (PASD). The diagnosis was made by echocardiographic observation of the PASD and goose-neck deformity on left ventriculogram. The PASD was treated surgically with a patch graft under cross-circulation cardiopulmonary bypass (CC). The PASD was identified above the ventricular septum after right atriotomy. The patch graft was sutured along the fibrous tissue of the tricuspid annulus on the ventricular side of the PASD to avoid injuring the conduction system. After the operation, cardiac function and renal output were well preserved, but the dog died 33 hr later. At postmortem examination, a mitral cleft was identified.

Intraoperative radiation therapy for brain tumors with emphasis on retreatment for recurrence following full-dose external beam irradiation

We performed intraoperative radiotherapy (IORT) in 19 patients with various brain tumors. IORT was given for primary tumors in 2 patients with malignant glioma, but was used for treating recurrent tumors in the other 17 patients. The former 2 patients respectively received 33 Gy by IORT alone and 30 Gy by IORT in combination with 50 Gy of external beam radiotherapy (EBRT), and survived for 12 and 9 months. The latter 17 patients had received EBRT at 4 to 112 months before IORT. In this group, single doses of 23-40 Gy were delivered by IORT after removing as much tumor as possible. The median survival time after IORT was 12 months for 9 patients with glioblastoma or anaplastic astrocytoma, while it was 51 months for 8 patients with less infiltrative tumors (ependymoma, anaplastic ependymoma, and anaplastic oligodendroglioma). One patient with ependymoma and another with anaplastic ependymoma are currently alive with no evidence of disease at 7 and 11 years after IORT, respectively. Symptomatic brain necrosis occurred in 3 patients following IORT, but the symptoms were relieved in 2 of them by the removal of necrotic brain tissue. It is concluded that IORT combined with extensive tumor removal has an acceptable toxicity in previously irradiated patients and can be effective for selected recurrent malignant brain tumors.

Hydroxyl group of Tyr13 is essential for the activity of omega-conotoxin GVIA, a peptide toxin for N-type calcium channel

A series of analogs of omega-conotoxin GVIA, a peptide neurotoxin having 27 amino acid residues with three disulfide bridges, were synthesized by replacing each amino acid residue except for Cys and Hyp with Ala. CD spectra were virtually identical between native and all of the analogs, indicating the overall conformations were not changed by the substitutions. The inhibitory effects of these analogs on 125I-omega-conotoxin GVIA binding to chick brain synaptic plasma membranes showed that replacement of Tyr13 with Ala drastically lowered the affinity of the toxin to the N-type Ca2+ channel. Substitution of Tyr13 with Phe also showed reduction of the affinity, indicating that the hydroxyl group of Tyr13 is critical for binding. Since Lys2 is also important for binding (Sato, K. Park, N.-G., Kohno, T. Maeda, T., Kim, J.-I., Kato, R., and Takahashi, M. (1993) Biochem. Biophys. Res. Commun. 194, 1292-1296), we propose a two-point binding model in which Tyr13 and Lys2 interact with specific amino acid residues of the Ca2+ channel through hydrogen bonding and ionic interaction, respectively.

Involvement of LDL receptor in the proliferation of vascular smooth muscle cells

To study the involvement of the low-density lipoprotein (LDL) receptor in the growth of vascular smooth muscle cells (VSMC), we compared the proliferation of cultured VSMC from Watanabe heritable hyperlipidemic (WHHL) rabbits, which lack the LDL receptor, and VSMC from normal Japanese white rabbits in response to platelet derived growth factor (PDGF). The increase in the number of VSMC from WHHL rabbits in response to PDGF (10(-8) M) was significantly lower than that of VSMC from normal rabbits. PDGF stimulated the synthesis of DNA in VSMC from both normal rabbits and WHHL rabbits, but the response was significantly lower in the latter. To determine the involvement of the LDL receptor in the decreased mitogenic response of WHHL rabbit VSMC, we used an anti-LDL receptor monoclonal antibody (MAb) to normal rabbit VSMC; DNA synthesis of VSMC was stimulated by PDGF, but the effect was significantly blocked by the anti-LDL receptor MAb. Mitogen-activated protein (MAP) kinase activity in normal rabbit VSMC was increased by exposure to PDGF, but the effect was significantly suppressed in the presence of the MAb. The anti-LDL receptor MAb markedly inhibited LDL binding to the surface of normal rabbit VSMC. These results suggest that the LDL receptor influences the proliferation of VSMC and thus might be involved in the pathogenesis of atherosclerosis.

Immunohistochemistry with an antibody to human liver carboxylesterase in human brain tissues

Human liver carboxylesterase (CE) is an enzyme capable of metabolizing drugs, and may also function as a regulator of lipid metabolism. We examined one isoform of CE by immunohistochemistry in the brains of neurologically normal, Alzheimer disease (AD), amyotrophic lateral sclerosis (ALS) and cerebral infarction cases. In all but the infarcted brains, the anti-CE antibody stained only capillary endothelial cells in the brain and spinal cord tissues. In infarct brain areas, intense immunoreactivity of the macrophages was seen. In contrast, the macrophages in the ALS lateral columns and the reactive microglia located in the center of classical senile plaques in AD, as well as other reactive microglial cells in the grey matter, showed no immunoreactivity. In the central nervous system, CE may function as a protective factor against foreign chemicals in capillary endothelial cells, and the antibody to CE may serve as a marker for invading macrophages from the systemic circulation.

DNA-binding parameters of the HU protein of Escherichia coli to cruciform DNA

We have previously studied the binding characteristics of the HU protein of Escherichia coli to different linear DNAs. In this work, using gel-retardation and footprint analysis, we studied the specific binding of HU protein to a synthetic cruciform DNA. We have quantified our results in order to precisely define the binding and cooperativity constants of HU protein towards cruciform DNA and compare them to those obtained with linear DNA. We used stringent high-salt conditions versus non-stringent low-salt conditions in order to differentiate the non-specific-protein HU-DNA complexes from the specific, high-salt-resistant complexes. We observe that HU-protein dimers bind specifically to the cruciform DNA with a binding constant K = 2.0 x 10(8) M-1 and a value for the cooperativity constant omega = 1 corresponding to a non-cooperative phenomenon. For the first time we observe a footprint pattern of HU protein bound to DNA using the hydroxyl-radical-footprinting technique on HU-protein-cruciform-DNA complexes. The residues protected by HU protein are localized at and near the junction point but interestingly they are mainly present in two of the four oligonucleotides which constitute the cruciform DNA. These two oligonucleotides are unpaired and opposite each other. These results support a model where two HU-protein dimers specifically bind to two equivalent angles present opposite each other in the four-way-junction-DNA structure with almost no dimer-dimer interactions.

Flow linear dichroism and electron microscopic analysis of protein-DNA complexes of a mutant UvrB protein that binds to but cannot kink DNA

(A)BC excinuclease of Escherichia coli is the enzymatic activity resulting from sequential and partially overlapping actions of UvrA, UvrB, and UvrC protein. UvrA is a molecular matchmaker which promotes the formation of a stable UvrB-damaged DNA complex in which the DNA is kinked by about 130 degrees. The UvrB-DNA complex is then recognized by UvrC and two incisions are made in the DNA by the joint actions of UvrC and UvrB. A mutant of UvrB (D478A) can be loaded onto the DNA but it does not interact with UvrC to cause a nick 3' to the lesion. Based on the lack of a DNase-I-hypersensitive site in the footprint of the mutant, it was proposed that the lack of incision was due to the inability of the mutant UvrB to kink the DNA. In the current study we have investigated the interaction of the mutant UvrB with DNA using two biophysical methods, flow linear dichroism and electron microscopy. Both methods reveal that the mutant UvrB is unable to bend DNA.

MR imaging of minamata disease: qualitative and quantitative analysis

Minamata disease (MD), a result of methylmercury poisoning, is a neurological illness caused by ingestion of contaminated seafood. We evaluated MR findings of patients with MD qualitatively and quantitatively. Magnetic resonance imaging at 1.5 Tesla was performed in seven patients with MD and in eight control subjects. All of our patients showed typical neurological findings like sensory disturbance, constriction of the visual fields, and ataxia. In the quantitative image analysis, inferior and middle parts of the cerebellar vermis and cerebellar hemispheres were significantly atrophic in comparison with the normal controls. There were no significant differences in measurements of the basis pontis, middle cerebellar peduncles, corpus callosum, or cerebral hemispheres between MD and the normal controls. The calcarine sulci and central sulci were significantly dilated, reflecting atrophy of the visual cortex and postcentral cortex, respectively. The lesions located in the calcarine area, cerebellum, and postcentral gyri were related to three characteristic manifestations of this disease, constriction of the visual fields, ataxia, and sensory disturbance, respectively. MR imaging has proved to be useful in evaluating the CNS abnormalities of methylmercury poisoning.

Effects of acute ozone exposure on the electrophysiological properties of guinea pig trachea

Acute ozone (O3) exposures produce an increase in the apparent permeability of the tracheal epithelium, but the mechanism of this response is poorly understood. Comparison of previous studies suggests that qualitative differences may exist between measurements made in vivo or in vitro. To test this possibility we used both in vitro and in vivo electrophysiological techniques to investigate the effects of O3 exposure on guinea pig tracheal epithelium. Male Hartley guinea pigs were exposed to either 1 or 2 ppm O3 or to filtered air for 3 h and were studied 0, 6, or 24 h after exposure. Air-exposed animals had in vitro mean tracheal potential (VT) -32.0 +/- 1.5 mV, conductance (GTL) 2.18 +/- 0.22 mS/cm, short-circuit current (ISCL) 62.6 +/- 3.7 microA/cm, and diameter (D) 2.44 +/- 0.10 mm. In vitro properties after 1 ppm O3 exposure did not differ at any time point from control. Two parts per million O3 increased ISCL, but only at 6 h postexposure. The effect of O3 on ISCL was abolished by amiloride. There were no significant changes in VT, GTL, or D. In vivo tracheal potential under pentobarbital anesthesia was -19.7 +/- 1.7 mV. At 6 h postexposure to 2 ppm O3, but not at 0 or 24 h, in vivo VT was increased. Thus, acute exposure of guinea pigs to a high concentration of O3 caused a delayed increase in Na+ absorption by the trachea with no change in conductance. This indicates that paracellular permeability of guinea pig tracheal epithelium was not substantially increased by acute O3 and suggests that enhanced macromolecular uptake in this species probably occurs transcellularly. Furthermore, the increase of in vivo VT following O3 exposure is consistent with the in vitro response, indicating that in vivo/in vitro differences are not responsible for the discrepancies between previous electrophysiological and "permeability" studies.

[Pelvic hyperthermochemotherapy combined with surgery for rectal cancer]

In an attempt to prevent local recurrence, intraoperative pelvic hyperthermochemotherapy (IOPHC) was performed in combination with curative surgery for rectal cancer. One hundred twenty-three patients were divided into four groups: A, 8 patients without nodal involvement (n0) and given IOPHC; B, 22 with nodal involvement (n+) and given IOPHC; C, 47 n0 and no IOPHC; D, 46 n (+) and no IOPHC. Local recurrence developed in one patient in group A (12.5%), 3 in group B (13.6%), 5 in Group C (10.6%), and 16 in Group D (34.8%), respectively. Thus, the rate of local recurrence in group B was low compared to that of Group D, even through there was no statistical difference (p = 0.11). IOPHC may be one option for limiting local recurrence after surgical resection of rectal cancer.

Mature cystic teratomas of the ovary without fat in the cystic cavity: MR features in 12 cases

OBJECTIVE

The diagnosis of mature cystic teratoma may be overlooked in the small number of cases that do not contain fat in the lumen of the cyst. The purpose of this study was to evaluate the MR appearance of mature cystic teratomas containing little or no fat and to determine the value of gradient-echo MR imaging for detection of small amounts of fat.

MATERIALS AND METHODS

In a review of pathologic specimens of 78 mature cystic teratomas, we found 12 tumors without fatty fluid (sebum) in their cystic cavity. Histologically, a small amount of fat was present in the wall of the cyst in each case. We retrospectively reviewed MR images of these tumors. In seven tumors with small amounts of hyperintense tissue on T1-weighted MR images, opposed-phase and in-phase gradient-echo MR images were obtained in order to verify the presence of fat.

RESULTS

All 12 lesions were hypointense on T1-weighted MR images and markedly hyperintense on T2-weighted images, indicating that the cystic cavity contained aqueous fluid. Fatty tissue was not identified in the lumen or wall of the cyst on MR images in five of the 12 tumors. In seven tumors, MR images showed small hyperintense areas in the walls of the cysts. These hyperintense signals were canceled on opposed-phase gradient-echo images. Characteristic MR findings for mature cystic teratoma, such as reversed chemical-shift artifact, gravity-dependent layering, or dermoid plug, were not observed in any of the lesions.

CONCLUSION

MR images in some cases of mature cystic teratomas may show aqueous fluid within the lumen of the cyst. In such cases, detection of fat in the cyst wall, especially with gradient-echo MR imaging, may help to establish the diagnosis.

[Concordant improvement of progressive systemic sclerosis and chronic myelogenous leukemia with interferon-alpha treatment]

A 44-year-old woman with progressive systemic sclerosis (PSS) visited our clinic because of leukocytosis and thrombocytosis. She was diagnosed as having chronic myelogenous leukemia (CML) with PSS, and was treated with interferon-alpha 2b (IFN-alpha) after pretreatment of hydroxyurea as a cytoreduction. Complete hematological remission was obtained two months later, and four months later minimal cytogenetic response was achieved by IFN-alpha. Her PSS symptoms were also improved to some extent as judged by Rodnan's total skin score, maximal opening distance of oral cavity, and range of motion of wrists. Our results suggest that IFN-alpha is probably beneficial not only for CML itself but also for PSS, too.

[Analysis of methods of administration on local arterial infusion chemotherapy for severe advanced hepatocellular carcinoma]

Between 1986 and 1994, hepatic local arterial infusion chemotherapy with implanted reservoir was performed for 51 patients with hepatocellular carcinoma (HCC) who were not indicated for surgery, PEIT and/or TAE because of the advanced stage of tumors and impaired liver function. We compared direct effects, survival rates, and rates of outpatients by dividing these 51 patients into 3 groups according to the methods of administration--repeated one-shot arterial infusion group, continuous arterial infusion group and intermittent high-dose arterial infusion group. There were no significant differences among these three groups in terms of background factors. The continuous infusion group had significantly better survival rates than the repeated one-shot infusion group, and the survival rate of the intermittent high-dose infusion group was similar to that of the continuous infusion group, although there were no significant differences in effectiveness among the three groups. Patients in the continuous infusion group and intermittent high-dose infusion group could receive almost all of their treatment as outpatients. Furthermore, more patients in the intermittent high-dose infusion group could receive whole treatment without hospitalization than patients in the continuous infusion group. Because intermittent high-dose arterial infusion of 5-FU showed about the same survival rate as continuous arterial infusion and because it can maintain high quality of life, it is suggested to be a standard method for local arterial infusion of 5-FU for severe advanced HCC.

Development of a new intraoperative radiofrequency ablation technique using a needle electrode

We studied a new intraoperative technique for radiofrequency ablation using a needle electrode. The ventricles of 12 mongrel dogs were ablated. The needle electrode was inserted to a depth of 3 mm through the epicardium. Macroscopically, tissue defect was found only at the needle insertion site. The degenerated area had a well-demarcated bullet shape with microscopical coagulation necrosis. This characteristic shape allows the ablation of deeper areas of the myocardium by deeper insertion of the ablation needle. Compared with conventional epicardial surface ablation, this new method could be used to achieve deeper coagulation. For any given energy level and conductance, the ratio between the volume and the depth of the lesion with this new method is smaller than that of lesions made by the conventional radiofrequency ablation method. With this new method, the energy spreads vertically, a characteristic suitable for deep ablation. This may result from the shape of the needle electrode itself. For ablation of deep targets, this new method is superior to the conventional approach because less myocardium is coagulated and the target can be ablated with greater efficiency, requiring the destruction of less tissue. In conclusion, the needle electrode procedure can achieve a narrower ablation for deeper targets than can the conventional technique.

Amino acids and peptides. XXIV. Preparation and antinociceptive effect of [D-Ala2,(N-Me)Phe4]enkephalin analog-poly(ethylene glycol) hybrids

Hybrids of amino-poly(ethylene glycol) (aPEG) and [D-Ala2,(N-Me)Phe4] enkephalin analogs, H-Tyr-D-Ala-Gly-(Me)Phe-aPEG, H-Tyr-D-Ala-Gly-(Me)Phe-Leu-aPEG and H-Tyr-D-Ala-Gly-(Me)Phe-D-Leu-aPEG, were prepared by the solution method and their antinociceptive properties were examined in comparison with those of the peptides. H-Tyr-D-Ala-Gly-(Me)Phe-OH and H-Tyr-D-Ala-Gly-(Me)Phe-Leu-OH themselves at intracerebroventricular (i.c.v.) doses of 10-30 nmol/animal produced an antinociceptive effect which was less potent than that of i.c.v. morphine, 3 micrograms/animal, and H-Tyr-D-Ala-Gly-(Me)Phe-D-Leu-OH did not have any marked effect. However, the antinociceptive effects of H-Tyr-D-Ala-Gly-(Me)Phe-Leu-OH and H-Tyr-D-Ala-Gly-(Me)Phe-D-Leu-OH were remarkably potentiated by hybrid formation with aPEG to levels higher than that of 3 micrograms/mouse of morphine, and the effect lasted at least 120 min. In contrast, the effect of H-Tyr-D-Ala-Gly-(Me)Phe-OH was rather diminished by hybrid formation. In view of the low toxicity and weak immunogenic properties of aPEG, the hybrids could be useful in therapy of patients for relieving chronic and severe pain.

[Determination of taurine, L-glutamine, vitamin U and L-aspartic acid in pharmaceuticals by high-performance liquid chromatography with pre-column derivatization]

A pre-column derivatization method for the high-performance liquid chromatographic determination of taurine (1), L-glutamine (2), vitamin U (3) and L-aspartic acid (4) in pharmaceuticals has been developed. The optimum requirements for the derivatization conditions and the stability of resulting derivatives were discussed. The compounds were converted into DNT derivatives through the amino group by reaction with sodium 2,6-dinitro-4-trifluoromethylbenzenesulfonate (DNTS) in 50% sodium borate at 60 degrees C for 30 min (1), at 60 degrees C for 90 min (2), at 60 degrees C for 80 min (3) and at 80 degrees C for 90 min (4). After the reaction mixtures were acidified with dil. HCl, the derivatives were separated on a Cosmosil 3C18 (4.6 mm i.d. x 50 mm) column using 1% acetic acid-methanol (13:7) containing 2 mM sodium 1-heptanesulfonate as mobile phase with a ultra violet detector at 280 nm. The precisions of the analytical values expressed as the coefficient of variation were below 2.0%. The recoveries of 1-4 added to various commercial samples were in the range of 97.8-100.6%.

The cofactor ATP in DNA-RecA complexes is not intercalated between DNA bases

In an attempt to understand the role of ATP as a cofactor at the interaction of the RecA protein with DNA, we have studied the orientation geometries of the cofactor analogs adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S) and guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) in RecA-DNA complexes using flow linear dichroism spectroscopy. Both cofactors promote the formation of RecA-DNA complexes of similar structure as judged from similar orientations of DNA bases. The DNA orientation was probed through the dichroism of the long-wavelength absorption of a DNA analog, poly(d epsilon A). In this way differences between the dichroic spectra of the ATP gamma S-RecA-DNA and GTP gamma S-RecA-DNA complexes, observed in the shorter-wavelength region, are related to orientation at variations of the cofactor chromophores. The results show that the guanine plane of GTP gamma S is oriented parallel with the principal axis of the complex in contrast to the more perpendicular orientation of the DNA bases. This observation directly excludes the possibility that the cofactor could be intercalated between the DNA bases. The orientation of the adenine base of ATP gamma S, which may be similar to that of guanine of GTP gamma S albeit not exactly the same, is also inconsistent with intercalation. The possibility that the cofactor bound to the protein could be intercalated in DNA had been speculated from the observation that some DNA intercalators can induce RecA binding to DNA in the absence of cofactor.(ABSTRACT TRUNCATED AT 250 WORDS)

Properties of RecA-oligonucleotide complexes

The interaction of RecA protein with short single-stranded oligonucleotides is characterised by flow linear dichroism (LD), isoelectric focusing (IEF) and electron microscopy (EM). From LD and EM it is evident that RecA forms long filaments with at least some 50 oligonucleotides in a 'train formation'. The tendency to form trains is substantially lower when an amino group is attached to the 5' end of the oligonucleotide, suggesting that the modification impairs protein-protein interactions at the interface between two oligomers. From LD it is also evident that no bridging occurs between RecA-oligonucleotide complexes containing more than one oligomer strand per RecA filament. This property make them manageable in polyacrylamide gels, hence allowing characterisation by IEF. RecA was found acidic with a pI of 5.0. The pI was not dependent on the presence of bound cofactor (ATP gamma S) and oligonucleotides suggesting that protonation of the protein readily occurs to compensate for the negative charges provided by bound cofactor and DNA.

Selegiline (L-deprenyl) and L-dopa treatment of Parkinson's disease: a double-blind trial

To confirm the clinical utility of selegiline (L-deprenyl), a selective inhibitor of monoamine oxidase B, as an anti-Parkinson's disease (PD) agent, the first Japanese multi-center, double-blind comparative study of this drug was conducted. The subjects were patients who had responded poorly or suffered with other problems related to L-dopa treatment. A total of 112 patients in two groups, one given selegiline at a dose of 7.5 mg/day (Group D, n = 60) and another given a placebo (Group P, n = 52), were compared over an 8-week treatment period. The percentage patients showing "moderate improvement" or better was 34.5% in Group D, while that in Group P was 11.5% (P < 0.01). In the assessment of overall safety, 66.7% in Group D showed no adverse reactions, which was not significantly different from the result of 78.9% for Group P.

Time after excision and temperature alter ex vivo tissue relaxation time measurements

Previously unreported effects of tissue storage were recently observed in the authors' experimental magnetic resonance (MR) studies. To evaluate the effect of elapsed time after excision and storage temperature on tissue relaxation time measurements, tissue samples from the liver, pancreas, kidney, testis, spleen, and brain were obtained in rats. T1 and T2 were first measured within 5 minutes of excision, and between subsequent measurements, tubes were kept in a water bath at 40 degrees C, at room temperature (28 degrees C), or in an ice bath (4 degrees C). Cellular and organellar integrity was assessed with electron microscopy and correlated with the MR findings. At 40 degrees C (20-MHz spectrometer), the T1 of liver decreased from 280 msec +/- 8 to 212 msec +/- 10 during the first 60 minutes; the T1 of pancreas decreased from 276 msec +/- 3 to 208 msec +/- 2. Other tissues showed less than a 5% decrease in T1. T2 changes were smaller than T1 changes in all tissues. Electron microscopy of pancreatic acinar cells showed postmortem changes in mitochondria evolving over the first 60 minutes after death. Manganese loading experiments implicated mitochondrial manganese stores in the observed enhanced postmortem decrease in T1. This study calls into question reported relaxation time data for liver and pancreas. MR studies of excised tissues must account for time and temperature to prevent systematic experimental errors.