Interaction between the left-handed Z-DNA and polyamine-2. The crystal structure of the d(CG)3 and spermidine complex

This paper deals with the crystal structure of d(CG)3-spermidine complex. The DNA fragment, d(CG)3, was crystallized with N-(2-amino-propyl)-1,4-diamino-butane, PA(34), spermidine. The results of its X-ray crystallographic analysis showed many intermolecular contacts between d(CG)3 and spermidine, but the binding mode of spermidine to the d(CG)3 molecule is different from that of the d(CG)3 and N-(2-amino-ethyl)-1,4-diamino-butane [PA(24)] complex: a spermidine molecule bound to the d(CG)3 and its symmetrically related neighboring d(CG)3 molecules through the water molecules with hydrogen bonds, while one PA(24) molecule connected directly to one d(CG)3 molecule, but not to its neighboring d(CG)3 molecule. In the crystal, the d(CG)3 molecule was the left-handed Z-form, and three magnesium cations and a sodium cation were observed around the d(CG)3 moiety with different binding modes from the case of the d(CG)3-PA(24) complex.

Magnesium metabolism in hyperthyroidism

Changes in magnesium metabolism, along with those in sodium, were investigated in 17 patients with Graves' disease (14 females and 3 males, mean +/- SD, 44.8 +/- 12.2 years) and their relationship to plasma levels of thyroid hormones were assessed before and after treatment. Each patient was studied in hyperthyroid state and euthyroid state after treatment. Each patient was studied in hyperthyroid state and euthyroid state after treatment with methimazole. Treatment with methimazole increased the magnesium concentration both in erythrocytes (2.00 +/- 0.18 vs. 2.08 +/- 0.24 mmol/l cells, P < 0.05) and in serum (0.72 +/- 0.12 vs. 0.84 +/- 0.11 mmol/l, P < 0.001) but both urinary output and fractional excretion of magnesium decreased significantly (P < 0.05 and P < 0.001, respectively). The erythrocyte sodium concentration decreased with treatment (10.7 +/- 2.6 vs. 8.1 +/- 1.1 mmol/l cells, P < 0.001) but the serum sodium remained unchanged (140.9 +/- 1.9 vs. 140.9 +/- 2.1 mmol/l, NS). Urinary excretion of sodium also decreased with treatment (P < 0.05), but only changes in indices of magnesium metabolism (decrease in renal fractional excretion, rise in serum level) correlated significantly with those of the thyroid functions with treatment. These observations clearly indicate that in Graves' disease, the magnitude of magnesium metabolism alteration is closely related to the extent of the increase in thyroid hormones in plasma.

Mash1 promotes neuronal differentiation in the retina

BACKGROUND

Mash1, a mammalian homologue of Drosophila achaete-scute proneural gene complex, plays an essential role in differentiation of subsets of peripheral neurones. Whereas Mash1 is expressed during retinal development, no apparent abnormalities were found during embryogenesis as well as at birth in Mash1-null retina, suggesting that early differentiating cells such as ganglion, amacrine and cone cells develop normally. Because Mash1-null mice die soon after birth, their postnatal development cannot be examined in vivo. Thus, it remains to be determined whether or not Mash1 functions in postnatal development of retina.

RESULTS

Here, Mash1 roles in postnatal development of retina was examined by using retinal explant that develops like in vivo retina. Without Mash1, differentiation of late appearing cells such as rod, horizontal, and bipolar cells was delayed and the final number of bipolar cells was significantly reduced. In contrast, vimentin-positive cells (probably Muller glial cells) were increased in Mash1-null retina.

CONCLUSIONS

These results provide evidence that Mash1 promotes neuronal differentiation during retinal development and is essential for proper ratios of retinal cell types.

Three-dimensional structure of a DNA repair enzyme, 3-methyladenine DNA glycosylase II, from Escherichia coli

The three-dimensional structure of Escherichia coli 3-methyladenine DNA glycosylase II, which removes numerous alkylated bases from DNA, was solved at 2.3 A resolution. The enzyme consists of three domains: one alpha + beta fold domain with a similarity to one-half of the eukaryotic TATA box-binding protein, and two all alpha-helical domains similar to those of Escherichia coli endonuclease III with combined N-glycosylase/abasic lyase activity. Mutagenesis and model-building studies suggest that the active site is located in a cleft between the two helical domains and that the enzyme flips the target base out of the DNA duplex into the active-site cleft. The structure of the active site implies broad substrate specificity and simple N-glycosylase activity.

[Allergic bronchopulmonary mycosis caused by Schizophyllum commune]

In December 1989, a 72-year-old woman was hospitalized with atelectasis in the left lower lobe. The atelectasis resolved after bronchoscopic removal of impacted mucous plugs. Histopathological examination showed pulmonary mycosis. Microscopy suggested that a species of Aspergillus was responsible, but no definite diagnosis was made. After treatment with flucytosine and nebulized amphotericin, the patient's condition improved and she was discharged. In the middle of August 1994, she visited a local hospital complaining of fatigue. Eosinophilia (22%) was detected, and a few days later she visited that hospital again due to sudden dyspnea. A chest X-ray examination showed an abnormal shadow, and she was referred to our hospital. Atelectasis was seen in the left upper lobe. This finding, together with eosinophilia, suggested recurrence of pulmonary mycosis, and therefore bronchoscopy was performed. White mucous plugs obstructing the left upper lobe were observed and were bronchoscopically removed. Microscopical examination of the mucous plugs showed marked eosinophil infiltration and hyphae. Cultures of specimens obtained during bronchoscopy showed Schizophyllum commune, and allergic bronchopulmonary mycosis due to this microorganism was diagnosed. Identification of this microorganism as a cause of deep-seated pulmonary mycosis is very rare.

Posterior limbus vertebral lesions causing lumbosacral radiculopathy and the cauda equina syndrome

This report reviews our experience with spinal decompression for posterior limbus vertebral lesions or osteocartilaginous vertebral corner defects in the lumbar spine in 29 children and young adults. There were 19 male and 10 female patients with a mean age of 16.5 years (range, 9 to 24 years). Twenty-four patients were involved with various athletic activities. Clinical presentation included low back pain with a variable degree of radiculopathy in 25 patients and a cauda equina syndrome in four. The level of the affected spinal area was L1-2 in one patient, L2-3 in one, L3-4 in seven, L4-5 in 17, and L5-S1 in three. The preoperative imaging workup showed lateralised "non-calcified' or 'calcified' limbus vertebral defects in 13 patients and centrally displaced lesions in 16 patients. All patients underwent posterior spinal decompression with a slightly extended laminotomy, except for three patients who had a subsequent posterolateral fusion. All of the patients consequently returned to practice their favourite preoperative sport and lifestyle, but five discontinued their previous sports. We suggest that patients with posterior limbus vertebral lesions require careful diagnosis and therapy that are different from those with an ordinary lumbar disc herniation.

Cadaveric vascular anatomy for total en bloc spondylectomy in malignant vertebral tumors

STUDY DESIGN

The authors studied the vascular anatomy of the thoracic and lumbar spine in cadavers related to the clinical use of total en bloc spondylectomy in malignant vertebral tumors.

OBJECTIVE

To enhance anatomic knowledge on major and associated segmental vessels surrounding the anterior vertebral column of the thoracic and lumbar spine.

SUMMARY OF BACKGROUND DATA

No reports have, to the authors' knowledge, referred clinically to the anatomic relationship between the vascular system and the anterior vertebral column in performing posterior total en bloc spondylectomy on the thoracic and lumbar spine.

METHODS

The authors studied the major vessels, segmental arteries and veins, and tendinous portions of the lumbar diaphragm inserting onto the vertebrae in 21 cadavers to view the vascular system surrounding the anterior vertebral column in the thoracic and lumbar spine.

RESULTS

The aorta descended in direct contact with the anterior vertebral column below T4 or T5 and branched into two common iliac arteries at L3 in one cadaver, at L3-L4 in two, at L4 in eight, at L4-L5 in nine, and at L5 in one. The uppermost intercostal artery originated at T4 or T5, and 48 (14%) variations in 348 intercostal arteries did not originate from the thoracic aorta. Two common iliac veins became confluent at L3-L4 in one subject, at L4-L5 in 13, and at L5 in seven. The inferior vena cava ascended in tight contact with the vertebral column and entered into the vena caval foramen of the diaphragm anterior to the right medial crus. The right medial crus of the diaphragm originated from the vertebra at L1-L2 in one subject, at L2 in two, at L2-L3 in 14, and at L3-L4 in four, whereas, on the left, this ligamentous origin located at L1-L2 in six, at L2 in two, at L2-L3 in 11, and at L3-L4 in two. The first two lumbar arteries ran consistently in the space between the medial crus and the vertebral column.

CONCLUSIONS

Total en bloc spondylectomy conducted posteriorly is less likely to damage the thoracic aorta from T1 to T4 but, distal to T5, the aorta must be carefully retracted anteriorly before manipulation of the affected vertebra(e). For a malignant tumor involving L1 or L2, the medial and, occasionally, the intermediate crura of the diaphragm and the first two lumbar arteries must be treated carefully before spondylectomy. Malignant tumors involving the L3 and L4 vertebral bodies can be approached with a total en bloc spondylectomy technique only when the inferior vena cava has been safely retracted anteriorly.

Total knee arthroplasty covered with pedicle peroneal flap

Three cases of total knee arthroplasty (TKA) covered with pedicle peroneal flaps are reported. One peroneal flap was performed after TKA to correct post-TKA skin necrosis. Two peroneal flaps were performed before TKA to replace previous traumatic scar formed around the knee. All three TKAs were successful after the procedure. The thickness, elasticity, appearance, and durability of the peroneal flaps were more suitable for the skin around the knee than the gastrocnemius muscle flap or the local fasciocutaneous flap. As the peroneal flap was elevated as a pedicle flap, freedom of transfer was good, microanastomosis was not necessary, and no donor sites were needed from the contralateral limb. Scar tissue around the knee can be effectively replaced by the pedicle peroneal flap before TKA.

Cytokine-induced apoptotic cell death in a mouse pancreatic beta-cell line: inhibition by Bcl-2

Cytokines are thought to contribute to the induction of pancreatic beta-cell destruction in insulin-dependent diabetes mellitus. The molecular mechanisms that underlie beta-cell death were investigated by studying cytokine-induced cell death in beta-cell lines. A combination of three cytokines (interleukin-1 beta, tumour necrosis factor-alpha, and interferon-gamma) induced apoptotic cell death in the mouse pancreatic beta-cell line beta TC1, as judged from the appearance of cells with hypodiploid nuclei and oligonucleosomal DNA fragmentation. The same treatment also induced apoptosis in the mouse pancreatic alpha-cell line alpha TC1 and the NOD/Lt mouse beta-cell line NIT-1, although to a lesser extent than in beta TC1 cells. The abundance of endogenous Bcl-2 in beta TC1 cells was lower than that in the other two cell lines. Overexpression of human Bcl-2 in beta TC1 cells partially protected them from cytokine-induced cell death. These results suggest that apoptosis may be responsible, at least in part, for cytokine-induced beta-cell destruction and that Bcl-2 prevents apoptosis in pancreatic islet cells.

Time change of nicardipine effect on choroidal circulation in rabbit eyes

PURPOSE

To investigate the time course of effects of intravenous administration of a calcium antagonist, nicardipine, on the choroidal circulation of rabbit eyes using a laser speckle tissue circulation analyzer.

METHOD

The rabbit fundus was illuminated by a diode laser spot and its image speckle was detected by an image sensor. The difference between the average of the speckle intensity (Imean) and the speckle intensity for successive scannings was calculated, and the ratio of Imean to this difference was defined as normalized blur (NB); a quantitative index of tissue blood velocity. The average NB over the field measured (0.620.62 mm in the choroid) was calculated to give Nb(av). Under general anesthesia, 0.4 ml/kg of 0.01% nicardipine hydrochloride dissolved in physiological saline was injected intravenously in a group of albino rabbits (control group) for measurement in the choroid (nicardipine groups). To serve as control, 0.4 ml/kg of physiological saline was injected in other groups of albino rabbits (control groups). Nb(av) was recorded at 1-min intervals for the first 5 min and at 5-min intervals for the next 85 min. During the experiment mean femoral arterial blood pressure (FABPm), pulse rate (PR), arterial blood pH, Pco2 and Po2 body temperature (BT) and intraocular pressure (IOP) were also monitored. Before and 45 min after nicardipine administration, the choroidal blood flow measurement using the microsphere technique and the Nb(av) measurement were carried out in the same eye in another group of rabbits.

RESULTS

Only the rabbits which did not show any significant change in the PR, pH, Pco2, Po2 and BT during the experiment were accepted. FABPm in the nicardipine group dropped to the minimum at 1 min postadministration and this level remained significantly lower than that in the control group up to 15 min post-injection, while te 10P did not show any significant change. The Nb(av) in the nicardipine group showed a significant increase after the FABPm return to the baseline, which was maintained throughout the experiment. The averaged increase between 30 and 90 minutes after administration was 27 +/- 1% (mean +/- S.E.M., n = 10). Relative increase in choroidal blood flow determined by the microsphere technique showed a good correlation (r = 0.90, P < 0.001, n = 12) with those determined by Nb(av) after nicardipine administration.

CONCLUSIONS

The present result indicates that the time course of drug effects on the choroidal circulation can be noninvasively and sensitively followed by Nb(av) measurements. Further, it was shown that nicardipine may have considerable potential for the treatment of ocular diseases associated with insufficient choroidal blood flow and that nicardipine's effects here observed deserve to be further studied in humans.

Mammalian hairy and Enhancer of split homolog 1 regulates differentiation of retinal neurons and is essential for eye morphogenesis

Mammalian hairy and Enhancer of split homolog 1 (HES1), a basic helix-loop-helix factor gene, is expressed in retinal progenitor cells, and its expression decreases as differentiation proceeds. Retinal progenitor cells infected with HES1-transducing retrovirus did not differentiate into mature retinal cells, suggesting that persistent expression of HES1 blocks retinal development. In contrast, in the retina of HES1-null mutant mice, differentiation was accelerated, and rod and horizontal cells appeared prematurely and formed abnormal rosette-like structures. Lens and cornea development was also severely disturbed. Furthermore, in the mutant retina, bipolar cells extensively died, and finally disappeared. These studies provide evidence that HES1 regulates differentiation of retinal neurons and is essential for eye morphogenesis.

THE ILIZAROV METHOD IN THE MANAGEMENT OF GIANT-CELL TUMOURS OF THE PROXIMAL TIBIA

We have used the Ilizarov technique for the management of subarticular defects after the excision of giant-cell tumours in the proximal tibia in five patients. The defect was reconstructed with a segment of 5 to 6 cm obtained from the diaphysis of the affected tibia and by autogenous bone graft from the iliac crest. The newly developed defect in the diaphysis was reconstructed by distraction using the Ilizarov apparatus. Bone grafting at the docking site was performed soon after positioning the bone segments.

The mean length of the bone defect was 5.7 cm and the mean duration of external fixation was 233 days. The relative blood flow in the leg measured by 99mTc angiography increased by 1.7 to 2.3 times that of the control level during distraction and consolidation. When seen at a mean of 43 months all patients showed a normal range of motion in the knee and ankle with no collapse of the articular surfaces.

[Na+/K+/2Cl- cotransport protein, Na+/Cl- cotransport protein]

The bumetanide-sensitive Na+/K+/2Cl- cotransporter and the thiazide-sensitive Na+/Cl- cotransporter are present in a wide variety of tissues, and appear to serve physiological cell functions such as volume control, particularly the phenomenon known as regulatory volume control, and net secretion or absorption of salt. The recent cDNA cloning of these two cotransporters suggests that they are members of the same new family, because they exhibit a topology featuring 12 potential membrane-spanning helices flanked by large hydrophilic domains at the NH2- and COOH-termini. The transporters are regulated by phosphorylation directly via protein kinase and dephosphorylation via phosphatase, and perhaps secondary to decrease of Cl concentration in the cell by activated Cl channel.

The Ilizarov method in the management of giant-cell tumours of the proximal tibia

We have used the Ilizarov technique for the management of subarticular defects after the excision of giant-cell tumours in the proximal tibia in five patients. The defect was reconstructed with a segment of 5 to 6 cm obtained from the diaphysis of the affected tibia and by autogenous bone graft from the iliac crest. The newly developed defect in the diaphysis was reconstructed by distraction using the Ilizarov apparatus. Bone grafting at the docking site was performed soon after positioning the bone segments. The mean length of the bone defect was 5.7 cm and the mean duration of external fixation was 233 days. The relative blood flow in the leg measured by 99mTc angiography increased by 1.7 to 2.3 times that of the control level during distraction and consolidation. When seen at a mean of 43 months all patients showed a normal range of motion in the knee and ankle with no collapse of the articular surfaces.

Examination of the safety of intracytoplasmic injection procedures by using bovine zygotes

We have evaluated the safety of intracytoplasmic sperm injection(ICSI) procedures by using bovine zygotes. Bovine zygotes were injected with a small amount (2-3 pl) of either medium alone or medium containing polyvinylpyrrolidone (PVP) (sham-ICSI, without spermatozoon) using the same procedure as ICSI, and the subsequent in-vitro embryonic development and embryo quality (number of cells/blastocyst) were examined. Control zygotes which had not been injected were similarly evaluated after in-vitro development. The sham-ICSI of either medium alone or medium containing PVP into bovine zygotes had no harmful effects on the rate of normal fertilization and on the rate of development to hatched blastocyst stage compared with those of controls (P > 0.05). In addition, no harmful effects were observed in the number of cells per blastocyst (embryo quality). The results suggest, for the first time, that the ICSI procedures currently used for animal and human ICSI are neither detrimental to embryonic development nor detrimental to embryo quality.

Vertebral osteomyelitis presenting with bilateral pleural effusions in a leprous patient

We present a highly rare case of vertebral osteomyelitis due to Salmonella newport that was associated with pleural effusion in a leprous woman. The salmonella infection was considered to be precipitated by her hemolytic anemia resulting from dapsone. The direct spread of infection from the vertebrae led to the pleurisy.

Spinal cord evoked potential monitoring for cervical and thoracic compressive myelopathy

Spinal cord evoked potentials (SCEPs) were recorded epidurally in 95 surgical cases of cervical and/or thoracic compressive myelopathy. Abnormal SCEPs occurred in 91% of the patients with cervical myelopathy and in all with thoracic involvement at the levels suspected to be responsible for neurological damage. Abnormal SCEPs correlated significantly with the severity of spinal cord compromise and symptoms, such as myelopathy. It was not possible to predict postoperative neurological improvement on the basis of the preoperative SCEP findings alone, but better neurological improvement after surgery was closely associated with early recovery of intra- and postoperative SCEPs. Epidural SCEPs are therefore useful in making a level-specific diagnosis, especially in the patient with multilevel vertebral involvement, and in assessing the severity of neurological compromise and surgical outcome to some extent.

Quantitative analysis of the spinal cord motoneuron under chronic compression: an experimental observation in the mouse

We investigated quantitative changes in spinal cord motoneurons following chronic compression using a mouse model of cervical cord compression. Twenty-five tip-toe-walking Yoshimura (twy) mice with calcified mass lesions compressing the spinal cord posterolaterally at the C1-C2 vertebral levels were compared with five Institute of Cancer Research (ICR) mice that served as controls. Spinal cord motoneurons in the anterior grey horn between the C1 and C3 spinal cord segments were Nissl-stained and counted topographically and then analysed in relation to the extent of spinal cord compression. The number of motoneurons in C1-C3 spinal cord segments decreased significantly with a linear correlation with the transverse area of the spinal cord when the cord was compressed to 50-70% of control values. A significant reduction in the number of motoneurons occurred at the C2-C3 spinal cord segment compressed at the C1-C2 vertebral level. In contrast, at the level rostral to the C1 vertebra, the number of motoneurons increased significantly in proportion to the magnitude of compression. The current study demonstrates that a number of neurons, morphologically consistent with anterior horn cells, were observed at a rostral site absolutely free of external compression where no such cells normally exist.

Laminoplasty with foraminotomy for coexisting cervical myelopathy and unilateral radiculopathy: a preliminary report

STUDY DESIGN

An assessment was made of the efficacy of a combined laminoplasty and foraminotomy operation for patients with coexisting myelopathy and unilateral radiculopathy. The procedure was done in 17 patients.

OBJECTIVES

The patients were followed with lateral flexion and extension radiographs, computed tomography scans, and an assessment system specially designed to qualitatively evaluate the patients' neurologic status. Follow-up period averaged 4 years (range, 2.1-9.3 years).

SUMMARY OF BACKGROUND DATA

Excellent-to-good results were obtained for 76% (13 of 17) of the patients without any significant functional compromise based on the radiographs. Sixteen nerve roots were decompressed with a less than 25% foraminotomy, whereas eight were decompressed by a 25%-50% foraminotomy without serious neurologic damage, except for one patient. The neurologic results appeared unrelated to the extent of foraminotomy.

METHODS

A refined procedure for combined laminoplasty and foraminotomy was reviewed retrospectively in terms of neurologic outcome and radiographic data.

RESULTS

The present series is small, and results are not comparable directly with other methods. The procedure appears effective for myelopathy and radiculopathy. This procedure is applicable to patients with myelopathy and coexisting nerve root impingement anterolaterally or in the neural foramen.

CONCLUSION

The combined laminoplasty and foraminotomy operation may provide greater neurologic improvement in patients with coexisting myelopathy and unilateral radiculopathy, while maintaining cervical spine stability after surgery.

Two nucleotides 5'-adjacent to the anticodon of rat cytoplasmic tRNA(Asp) are not edited

Cytoplasmic tRNA(Asp) of rat liver was purified by the solid-phase hybridization method and its nucleotide sequence was analyzed by Donis-Keller's method. The results suggested that the two nucleotides next to the anticodon were identical to its gene sequence, a finding that is inconsistent with a previous report demonstrating by several methods that C32 and T33 on the tRNA(Asp) gene are post-transcriptionally converted to U32 and C33, respectively (Beier et al (1992) Nucleic Acids Res 20, 2679-2683). Our results indicate that the tRNA hybridized to an oligonucleotide, designed on the basis of the tRNA(Asp) gene sequence, undergoes no editing and possesses C32 and U33 as predicted from the DNA sequence. Analysis of cDNA synthesized from the purified tRNA(Asp) by the RT-PCR method supported the finding that RNA editing is not involved in the maturation process of rat cytoplasmic tRNA(Asp).

[Effect of topical adrenergic agents on tissue circulation in human optic nerve head evaluated with a laser speckle microcirculation analyser]

The effects of a single instillation of 2% carteolol or 0.1% dipivefrine on the tissue circulation in the human optic nerve head (ONH) was studied using a laser speckle tissue circulation analyser in 12 healthy volunteers. In the first experiment, normalized blur (NB), a quantitative index of peripheral blood velocity, was measured every 0.125 sec in an area located in the temporal site of ONH free of visible surface vessels and averaged over 5 pulses (mean NB) in both eyes before, 1.5, 3, and 4.5 hours after a 30 microliters instillation of placebo to serve as a control. Intraocular pressure (IOP), blood pressure (BP), and pulse rate (PR) were also measured. In the second experiment, a 30 microliters drop of 2% carteolol (n = 6) or 0.1% dipivefrine (n = 7) was instilled in one randomly chosen eye and the placebo for each drug in the other eye, and the above parameters were measured according to the same time schedule as in the first experiment in a double masked manner. After topical carteolol, carteolol concentration in the plasma (CC) was also measured. In the control experiments, none of the parameters showed any significant change. After topical carteolol, the IOP was significantly lower between 1.5 and 4.5 hrs in the carteolol-treated eyes and at 1.5 and 4.5 hrs in the fellow eyes as compared with that obtained in the control experiment. The mean NB was significantly higher at 3 hrs (23.1%) in carteolol-treated eyes, and at 3 hrs (17.2%) in the fellow eyes, as compared with that obtained in the control experiment (p < 0.05). BP and PR showed little change. The maximum CC at 3 hrs averaged 522 pg/ml. Thus a single instillation of carteolol may increase the tissue blood velocity in ONH in the human eye. After topical dipivefrine, the IOP was significantly lower at 4.5 hr in the dipivefrine-treated eyes than that obtained in the control experiment (p < 0.05). Mean NB, BP and PR showed no significant change.