Glycine-15 in the bend between two alpha-helices can explain the thermostability of DNA binding protein HU from Bacillus stearothermophilus

On the basis of sequence comparison of thermophilic and mesophilic DNA binding protein HUs, Bacillus stearothermophilus DNA binding protein HU (BstHU) seems to gain thermostability with a change in amino acid residues present on the molecular surface. To evaluate the contribution of exchange of each amino acid to the thermostability of BstHU, we constructed three mutants, BstHU-T13A (Thr13 to Ala), BstHU-G15E (Gly15 to Glu), and BstHU-T33L (Thr33 to Leu), in which the amino acids in BstHU were changed to the corresponding ones in Bacillus subtilis DNA binding protein HU (BsuHU). Stability of the mutant proteins was determined from thermal-denaturation curves. Replacement of Gly15 located in the turn region between alpha 1 and alpha 2 helices (HTH motif), with Glu (BstHU-G15E), resulted in a decrease in thermostability, and the Tm value was 54.0 degrees C compared to the Tm value of 63.9 degrees C for BstHU. The mutants, BstHU-T13A and BstHU-T33L, were, by contrast, slightly more stable (Tm values of 67.0 and 65.6 degrees C for BstHU-T13A and BstHU-T33L, respectively) than the wild type. We then generated the BsuHU mutant protein BsuHU-E15G, where Glu15 in BsuHU was in turn replaced by Gly, and we analyzed the thermostability. This substitution clearly enhanced the melting temperature by 11.8 degrees C (Tm value: 60.4 degrees C for BsuHU-E15G) compared to the value for BsuHU (Tm: 48.6 degrees C). Thus, Gly15 in the HTH motif of BstHU has an important role in the thermostability of BstHU. Characterization of the structure of the BstHU-G15E by 1H-NMR analysis showed that solvent accessibility of amide proton of Ala21 in the mutant was significantly increased compared with that of wild type, which means that the structure of the HTH motif in the N-terminal region in the mutant was changed to a more open conformation, thereby avoiding the interaction of Ala21 with either Ser17 by hydrogen bond or Ala11 by hydrophobic interaction.

Highly sensitive and simple liquid chromatographic determination in plasma of B6 vitamers, especially pyridoxal 5'-phosphate

A simple and sensitive high-performance liquid chromatographic method for measuring the major vitamers of vitamin B6, i.e. pyridoxal and pyridoxal 5'-phosphate (PLP), and 4-pyridoxic acid (4-PA) in plasma was developed. The vitamers and 4-PA from plasma were extracted with 0.8 mol/l perchloric acid. The separation by HPLC is accomplished using an ODS reversed-phase column and a mobile phase of 0.1 mol/l potassium dihydrogen phosphate containing 0.1 mol/l sodium perchlorate, 0.5 g/l sodium bisulfite adjusted to pH 3, at a flow-rate of 1.0 ml/min. The vitamers and 4-PA were eluted within 13 min and their concentration is determined with a fluorometric detector (excitation, 300 nm; emission, 400 nm). In this method, PLP in plasma can be determined with high sensitivity using derivatization with sodium bisulfite in the mobile phase.

Granulocyte/macrophage colony-stimulating factor is an intrinsic keratinocyte-derived growth factor for human melanocytes in UVA-induced melanosis

Recently we demonstrated that endothelins secreted from human keratinocytes act as intrinsic mitogens and melanogens for human melanocytes in UVB-induced melanosis. We show here that UVA-induced melanosis is associated with other keratinocyte-derived growth factors, secretion of which is specifically stimulated after exposure of human keratinocytes to UVA. Medium conditioned by UVA-exposed human keratinocytes elicited a significant increase in DNA synthesis by cultured human melanocytes in a UVA dose-dependent manner. Analysis of endothelin-1 and interleukin (IL)-1 alpha in the conditioned medium by ELISA, both of which are major keratinocyte-derived cytokines involved in UVB-associated melanocyte activation, revealed that UVA exposure did not cause human keratinocytes to stimulate the secretion of the two cytokines. In contrast, the levels of several other cytokines such as IL-6, IL-8 and granulocyte/macrophage colony-stimulating factor (GM-CSF) were significantly increased in the conditioned medium of human keratinocytes after exposure to UVA at a dose of 1.0 J/cm2. The gel chromatographic profile of UVA-exposed keratinocyte-conditioned medium demonstrated that there were two factors (P-1 and P-2) with molecular masses of approx. 20 and 1 kDa respectively that stimulate DNA synthesis in human melanocytes, and the larger species (P-1) also increased melanization as assessed by [14C]thiouracil incorporation. Quantitative analysis of cytokines in chromatographic fractions by ELISA revealed the P-1 fraction to be consistent with the molecular mass profile of GM-CSF. Furthermore the stimulatory effect of the P-1 fraction on DNA synthesis in human melanocytes was neutralized by antibodies to GM-CSF, but not to basic fibroblast growth factor or stem cell factor. Binding and proliferation assays with recombinant GM-CSF demonstrated that human melanocytes possess specific binding sites for GM-CSF(Kd 2.11 nM; binding sites, 2.5-3.5 x 10(4) per cell), and recombinant GM-CSF at concentrations of more than 10 nM significantly stimulated DNA synthesis and melanization. These findings suggest that GM-CSF secreted by keratinocytes plays an essential role in the maintenance of melanocyte proliferation and UVA-induced pigmentation in the epidermis.

Preference of lymphocyte-homing to high endothelial venules in palatine tonsils of musk shrew (Suncus murinus)

We studied the lymphocyte-homing to palatine tonsils of the musk shrew, a new experimental animal originally developed in Japan. The tonsils of the animals have typically high endothelial venules (HEV) in the parafollicular region. The in vivo migration test showed that blood-circulating lymphocytes were able to home to the tonsils through the HEV. The in vitro lymphocyte-HEV binding assay clearly indicated the binding preference of the lymphocytes to be the tonsillar HEV. First, binding of B cells to the tonsillar HEV was seen to a greater extent than that of T cells, which was consistent with the result in the assay of Peyer's patch. Second, binding of lymphocytes from axillar and inguinal lymph nodes was similar to that of lymphocytes from the mesenteric lymph nodes, which differed from the result in the assay of Peyer's patch. These findings suggest that, in the musk shrew, the regulation of lymphocyte-homing through the HEV is different in the tonsil and Peyer's patch, at least in part. These homing properties of musk shrew tonsils may reflect their immunological role in the local response against oral antigens.

In vitro/in vivo difference in enhanced skin permeation of nicardipine hydrochloride by the 1-menthol-ethanol system

The in vitro/in vivo difference in enhanced skin permeation of nicardipine hydrochloride (NC) by simultaneous use of 1-menthol and ethanol (MEW system, 1-menthol:ethanol:water = 5:40:55) was investigated in hairless rats. First, the cutaneous blood flow clearance (clearance from skin to blood flow) of NC per unit area of skin (CLCB/A), which was comparable to the permeability coefficient across skin (PC), was calculated from intracutaneous and intravenous injection data using the deconvolution method; the value was 1.67 microliters/h/cm2. Two formulations containing NC and the MEW system, solution (SOL) and 15% hydroxypropyl cellulose gel (GEL), were used for in vitro and in vivo permeation experiments. The in vitro PC of NC via excised skin from SOL (23.3 microliters/h/cm2) was significantly higher than CLCB/A, and that from GEL (1.48 microliters/h/cm2) was similar to CLCB/A. Consequently, the steady-state concentration of NC in skin during in vivo application of SOL was 6.6 times higher than corresponding in vitro data. In vivo PCs from SOL and GEL were however significantly lower than CLCB/A. These results may be explained by the findings, using a laser Doppler flowmeter, that cutaneous blood flow was decreased by the application of MEW.

Inhibitory effects of traditional Chinese medicine Shimotsu-to and its included crude fractions on adjuvant-induced chronic inflammation of mice

Effects of a traditional Chinese medicine, Shimotsu-to (a combined prescription of cnidium rhizome, peony root, angelica root and rehmannia root), and its included crude fractions were investigated on an adjuvant-induced chronic inflammation model of mice. The aqueous extract (30, 100 and 300 mg/kg, i.p.) of Shimotsu-to reduced the carmine content, granuloma weight, inflammation cell count and pouch fluid weight in the inflammation model, respectively. The extract of Shimotsu-to without cnidium at the same doses did not produce significant changes in these four inflammatory parameters. The same doses of extracts of Shimotsu-to without peony, and without angelica, weakly reduced these parameters, except for pouch fluid weight. The extract (30, 100 and 300 mg/kg) of cnidium significantly reduced these four parameters. The same doses of peony extract reduced carmine content, granuloma weight and pouch fluid weight, but less than those of the cnidium extract. The extract of cnidium and peony at the same doses reduced in an additive manner these inflammatory parameters in their combination. These results demonstrated that the Shimotsu-to extract reduced angiogenesis, granuloma formation, inflammatory cell migration and pouch fluid exudation in the adjuvant-induced chronic inflammation model. Cnidium represented the main ingredient for producing the anti-chronic inflammatory effects of Shimotsu-to extract. Cnidium and peony exhibited additive anti-inflammatory effects in combination.

Cerebrospinal fluid acetylcholine and choline in vascular dementia of Binswanger and multiple small infarct types as compared with Alzheimer-type dementia

The acetylcholine (ACh) and choline (Ch) concentrations in the cerebrospinal fluid were investigated in patients with vascular dementia of the Binswanger type (VDBT) or multiple small infarct type (MSID) as compared with patients with Alzheimer-type dementia (ATD). The ACh concentration in patients with ATD was found to be significantly lower than in controls (73%, p < 0.0001), and showed a significant positive correlation with dementia scale scores (rs = 0.63, p < 0.03). The Ch concentration in the CSF of ATD patients was approximately the same as in controls. In VDBT/MSID patients, the ACh concentration was significantly lower than in controls (p < 0.001) also showing a significant positive correlation with dementia scale scores (rs = 0.62, p < 0.02), but was significantly higher than in ATD patients (p < 0.001). Moreover, the Ch concentration in VDBT/MSID patients was significantly higher than in controls (p < 0.001) or ATD patients (p < 0.001). These results suggest that simultaneous determination of ACh and Ch concentrations in CSF may be useful for differentiating VDBT/MSID from ATD and that increasing the ACh level using cholinergic agents may be a beneficial therapeutic strategy for the treatment of ATD as well as VDBT/MSIT, and is worthy of further investigation.

Photosensitivity induced by fleroxacin

A case of photosensitivity induced by fleroxacin (FLRX) is reported. A 71-year-old man had erythema on sun-exposed areas after 5 months FLRX treatment for prostatitis. The minimal erythema dose to UVA was reduced at the initial examination and became normal 4 weeks after he stopped taking FLRX. Oral photo-challenge with FLRX 100 mg was positive, but photopatch testing was negative. Fleroxacin (FLRX), in use since 1992, is a fluoroquinolone antibacterial derived from quinoline. Photosensitivity induced by FLRX is not uncommon, but a photobiological study has not been reported. The mechanism of action of photosensitivity induced by the fluoroquinolones is considered to be phototoxic in origin in that in vitro technique studies are positive. FLRX, a quinoline derivative may be a photosensitizer as well as enoxacin, lomefloxacin and sparfloxacin.

[Epidemiology of pertussis and studies on culture positive pertussis cases in Japan]

The number of pertussis patients has decreased steadily in the late 1960s and was extremely small in early 1970s. During 1973-74 the first national survey on pertussis cases confirmed by culture was conducted, when whole cell pertussis vaccine was used. The study revealed that 33.3% of culture positive cases had 2-4 doses of DT combined with whole cell pertussis vaccine. Acellular pertussis vaccine was introduced in 1981 and for the last several years the number of pertussis patients became low for the second time. During 1988-92 exactly the same study was conducted as the previous one. Among 2501 pertussis cases diagnosed clinically 403 were culture positive. Most of the patients were below 1 year of age. Most of the patients were below 1 year of age. Clinical symptoms of those infants were more serious than those of older children. Only 7 out of 403 (1.8%) had a history of 2-4 doses of DT combined with acellular pertussis vaccine. This proved that the acellular pertussis vaccine is by far more effective than the whole cell pertussis vaccine. Serotypes of 377 Bordetella pertussis were identified and 370/377 (98.1%) were serotype 1-3 group.

Neurological disorder and excessive accumulation of calcium in brain of clinically vitamin A-deficient rats

Three groups of rats were fed two types of synthetic diets for 52 d. The -A group was allowed free access to a vitamin A-deficient diet and showed classical signs of vitamin A deficiency. The brain was the only organ in our experiment where no significant weight difference was present among the three groups. In the brain, calcium concentration was significantly higher in the -A group when compared with the PF (Pair-fed; allowed restricted amount of control diet) and +A groups (allowed free access to control diet). In the tibia, calcium and magnesium concentrations were significantly lower in the -A group when compared with other two groups. Excessive accumulation of calcium in brain and apparently similar unbalance in bone mineral concentration were observed in central nervous system (CNS) degenerative diseases. Our results suggest that abnormal metabolism of calcium and magnesium in some tissues and excessive accumulation of calcium in brain may be responsible for the development of neurological disorders in vitamin A-deficient rats.

Surgical implication of aortic dissection on long-term outcome in Marfan patients

We herein review our 17-year surgical experience for the treatment of ascending aortic aneurysm in patients with Marfan syndrome to clarify the risks of increased mortality and reoperation. The subjects consisted of 15 patients who had all undergone surgery for the aortic root and ascending aorta at Niigata University Hospital between July 1978 and January 1995. Aortic valve replacement and ascending aortic wrapping were performed in 5 patients, Bentall or Cabrol operation in 6, and combined aortic arch reconstruction and Cabrol operation in 2, as the initial surgery. Patients who had an aortic dissection (Stanford type A) at initial surgery were assigned to group I (n = 7), while those with an aortic root aneurysm were assigned to group II (n = 8). In group I, 3 patients required a second operation for the remaining aortic arch aneurysm, and 1 died due to a late rupture of the distal aneurysm. In group II, no patient needed a reoperation; however, 1 died due to an intracranial hemorrhage and another due to composite valve graft failure and distal dissection. The results thus indicate that aortic dissection seems to affect long-term outcome, and therefore the combined repair of the aortic root and transverse arch is recommended in Marfan patients with aortic dissection involving the transverse aortic arch.

Transforming and differentiation-inducing potential of constitutively activated c-kit mutant genes in the IC-2 murine interleukin-3-dependent mast cell line

Two mutations of c-kit receptor tyrosine kinase (KIT), valine-559 to glycine (G559) and aspartic acid-814 to valine (V814), resulted in its constitutive activation. To examine the transforming and differentiation-inducing potential of the mutant KIT, we used the murine interleukin-3-dependent IC-2 mast cell line as a transfectant. The IC-2 cells contained few basophilic granules and did not express KIT on the surface. The KITG559 or KITV814 gene was introduced into IC-2 cells using a retroviral vector. KITG559 and KITV814 expressed in IC-2 cells were constitutively phosphorylated on tyrosine and demonstrated kinase activity in the absence of stem cell factor, which is a ligand for KIT. IC-2 cells expressing either KITG559 or KITV814 (IC-2G559 or IC-2V814 cells) showed factor-independent growth in suspension culture and produced tumors in nude athymic mice. In addition, IC-2G559 and IC-2V814 cells showed a more mature phenotype compared with the phenotype of the original IC-2 cells, especially after transplantation into nude mice. The number of basophilic granules and the content of histamine increased remarkably. KITG559 and KITV814 also influenced the transcriptional phenotype of mouse mast cell proteases (MMCP) in IC-2 cells. The expression of MMCP-2, MMCP-4, and MMCP-6 was much greater in IC-2G559 and IC-2V814 cells than in the original IC-2 cells. The results indicated that constitutively activated KIT had not only oncogenic activity but also differentiation-inducing activity in mast cells.

Promotive action of acylated ascorbate on cellular DNA synthesis and growth at low doses in contrast to inhibitory action at high doses or upon combination with hyperthermia

Effects of 6-O-palmitoyl ascorbate (ascorbate) developed to increase the antitumour activity of ascorbic acid on DNA synthesis and proliferation of Ehrlich ascites tumour cells were investigated. Treatment of the cells with the acylated ascorbate at 25-50 microM for 1 h resulted in no effect on DNA synthesis, assayed by pulse incorporation of [3H]thymidine after a culture period of 20 h, but led to 49%-87% enhanced DNA synthesis after 4 days, suggesting that long-term culture is required for promotion by ascorbate to occur. At a dose as high as 75 microM acylated ascorbate, however, cellular DNA synthesis was 64% inhibited after 20 h and 99% after 4 days. The results suggest that acylated ascorbate exhibits a dual action on DNA synthesis: promotion at low doses and inhibition at high doses, both of which are potentiated in a time-dependent manner. In contrast to the above-mentioned results at 37 degrees C, acylated ascorbate at 25-75 microM inhibited but did not promote DNA synthesis at 42 degrees C whatever the culture period. Similar results were exhibited when proliferation of cells cultured for a long period was investigated. At 37 degrees C, 50 microM acylated ascorbate increased the number of the cells to 3.6 times the control values after 8 days and to 1.9 times after 11 days; in contrast, a 75-microM dose decreased the cell number considerably. Combination with hyperthermia (42 degrees C) suppressed the increase and cell growth was completely inhibited at 75 microM.

Laboratory suncus: a new model animal for tonsil research

Palatine and tubal tonsils of normal and horseradish peroxidase (HRP) sensitized laboratory suncuses (Suncus murinus) were examined by immunoelectron microscopy. The individual tonsil consisted of lymphoepithelial symbiosis containing M cells and a lymph nodule. The high-endothelial venules and efferent lymphatics were situated in the parafollicular region of the nodule. Staining of the frozen tonsil sections by our recently developed anti-Suncus T and B lymphocyte monoclonal antibodies revealed that T cells occupied the parafollicular zone and B cells localized within the follicles. In the present intra-tympanic cavity HRP sensitization, numerous HRP-antibody producing cells were seen not only in the tubal tonsils but also in their regional lymph nodes, spleen and palatine tonsils. The same HRP-antibody was rarely detected within the submesangial regions of the kidney. These findings presume that Suncus tonsil is homologous to the human tonsil. The Suncus is, therefore worthy as a model animal for tonsil research.

Recombinant human growth/differentiation factor 5 stimulates mesenchyme aggregation and chondrogenesis responsible for the skeletal development of limbs

We have expressed and biologically characterized recombinant human growth/differentiation factor 5 (huGDF5). This protein is composed of a mature homodimer consisting of 15 kD subunits. Using recombinant expressed protein, we have demonstrated that huGDF5 in vitro stimulated mesenchyme aggregation and chondrogenesis in rat limb bud cells. In vivo, partially purified huGDF5 induced cartilage and bone formation in muscular tissues of rodents. However, in contrast to the effects of other BMPs, as for example BMP-2, the osteoblastic MC3T3-E1 cells did not respond to huGDF5 as measured by alkaline phosphatase activity. These results suggest that the action of GDF5 may be relatively specific for chondrogenesis during the entire process of the endochondral bone formation. GDF5 may control the morphogenesis of cartilaginous tissue, including joints, in the skeletal development of limbs.

Post-TIPS hepatic encephalopathy treated by occlusion balloon-assisted retrograde embolization of a coexisting spontaneous splenorenal shunt

A 51-year-old man with posthepatitis cirrhosis underwent a transjugular intrahepatic portosystemic shunt (TIPS) for bleeding of recurrent esophageal varices. The patient had a coexisting, spontaneous, splenorenal shunt. He subsequently developed hepatic encephalopathy, presumably due to excessive portosystemic shunting. Since medical management resulted in no significant improvement, the splenorenal shunt was embolized from the jugular vein approach via renal vein access during temporary balloon occlusion. Within a few days, the patient's hepatic encephalopathy resolved. Twelve months later the patient showed no recurrence of encephalopathy and had maintained a patent TIPS.

Deafferentiation-induced c-fos gene expression in subthalamic nucleus and substantia nigra reticulata is reduced by non-NMDA receptor antagonist

Molecular events underlying the mechanism by which brain injury elicits delayed transneuronal degeneration of neurons remote from the site of initial injury are not well understood. In rats, acute injury of the caudate nucleus (CN) and globus pallidus (GP) by local injection of excitotoxic ibotenic acid (IA) or by transient forebrain ischemia resulted in delayed cell death of neurons in the substantia nigra reticulata (SNr). To elucidate the involvement of glutamate receptor mediated hyperactivity of neurons produced by loss of inhibitory inputs in this delayed degeneration of SNr neurons, the region-specific expression of an immediate early gene, c-fos, and the effect of glutamate receptor antagonists on the c-fos expression were examined by using immunocytochemical and in situ hybridization analysis. Following unilateral IA-injection into the CN and GP, a robust expression of c-fos mRNA and Fos protein was induced specifically in neurons of both subthalamic nucleus (STN) and SNr deafferented by the IA-lesions 36 h after IA-injection. The delayed expression of Fos-protein in SNr neurons lasted for 48 h longer than that in STN neurons. Following unilateral IA-injection confined to the CN, an intense but short-term expression of Fos-protein was exhibited only in neurons of the deafferented SNr. c-fos mRNA and Fos protein were not expressed in neurons of the substantia nigra compacta at any time points examined. The induction of c-fos mRNA and Fos protein in neurons of the STN and SNr following IA-lesions of the CN and GP was reduced markedly by non-NMDA receptor antagonist (GYKI52466), but not by NMDA receptor antagonist (MK-801). The region-specific c-fos expression implies that deprivation of inhibitory afferents (disinhibition) due to destruction of presynaptic neurons can induce increased activity of postsynaptic neurons. The effect of GYKI52466 on the c-fos gene expression in neurons of the deafferented STN and SNr suggests that activation of non-NMDA receptors may be involved in a pathophysiological cascade for the transneuronal degeneration of SNr neurons.

Anti-competence effects of synthetic phthalide derivatives on platelet-derived growth factor-induced DNA synthesis in primary cultures of rat aorta smooth muscle cells

The inhibitory effect of 3-butylidene-4,5-dihydroxyphthalide (BP-42) on platelet derived growth factor (PDGF)-BB-induced DNA synthesis was investigated in synchronized smooth muscle cells (SMC) in primary culture of rat aorta. BP-42 (0.3-3 micrograms/ml) inhibited the PDGF-BB (30 ng/ml)-stimulated [3H]thymidine incorporation of the SMC in a concentration-dependent manner. BP-42 inhibited both the competence and progression phases of [3H]thymidine incorporation induced by PDGF-BB. Using the competence assay, BP-42 (0.3-10 micrograms/ml) delayed PDGF-BB (30 ng/ml)-accelerated starting time of [3H]thymidine incorporation in a concentration-dependent manner, confirming that BP-42 inhibited PDGF-BB-induced competence phase of DNA synthesis of SMC. BP-42 (1-10 micrograms/ml) also delayed basic fibroblast growth factor (bFGF: 30 ng/ml)-accelerated starting time of [3H]thymidine incorporation. The inhibitory potency of BP-42 for the competence action of PDGF-BB was similar to that for the action of bFGF. BP-421 (3-heptylidene-4,5-dihydroxyphthalide) and BP-422 (3-benzylidene-4,5-dihydroxyphthalide) had 3-fold greater inhibitory potencies than BP-42 for the PDGF-BB-induced competence activity. These results demonstrated that BP-42 inhibited PDGF-BB-induced competence activity of DNA synthesis in primary cultured SMC of rat aorta via a common signal transduction mechanism with bFGF. BP-421 and BP-422 were more potent inhibitors for the competence activity, suggesting that they may become a prototype of new anti-atherosclerotic drugs.

Primary structure of a cysteine proteinase inhibitor from the fruit of avocado (Persea americana Mill)

The complete amino acid sequence of a proteinaceous cysteine proteinase inhibitor from the fruit of avocado (avocado cystatin) is presented. The protein consists of 100 amino acid residues and has a molecular mass of 11,300 Da. Comparison of this sequence with sequences of plant cysteine proteinase inhibitors (phytocystatins), including oryzacystatins I and II from rice seeds, cowpea cystatin, and corn cystatin, showed that the avocado cystatin molecule has 60% and 54% residues identical with the two forms of the rice seed proteins, oryzacystatins I and II, respectively, and 64% and 63% with the cowpea and corn proteins, respectively. The totally conserved sequence, Gln-Val-Val-Ala-Gly, among several of the animal cystatins as well as phytocystatins, is at positions 47-51 in the avocado cystatin molecule.

[Comparison of the clinical features of smear-positive and culture-positive tuberculous patients with smear-negative and culture-positive patients in an education hospital]

The clinical features of 27 smear-positive and culture-positive tuberculous patients (Group 1) were compared with those of 39 smear-negative and culture-positive patients (Group 2) experienced in our hospital. The proportion of the patients who have underlying diseases was lower in Group 1 than Group 2. Ninety-five % of the patients in Group 1 showed positive PPD skin reaction in comparison with 73% of the patients in Group 2. In most of the patients in Group 1, the chest X-ray findings were typical ones for pulmonary tuberculosis, but 36% of the patients in Group 2 showed atypical X-ray findings. Final diagnosis was more difficult for the patients in Group 2 than Group 1. Almost all patients in Group 1 could be diagnosed within a few days and were referred to a tuberculosis hospital for the treatment of tuberculosis. On the contrary, by the patients in Group 2, the final diagnosis was delayed more than one month until the results of culture was available. Also, many patients in this group had underlying disease and only 8 patients could be transferred to a tuberculosis hospital.

Functional map of the alpha subunit of Escherichia coli RNA polymerase: amino acid substitution within the amino-terminal assembly domain

The alpha subunit of Escherichia coli RNA polymerase plays a key role in assembly of the core enzyme. In previous studies the amino-terminal domain consisting of 215 amino acid residues between positions 21 and 235 was identified to be involved in this assembly, and the sites for beta and beta' association were suggested to be located within or near the two conserved regions in this amino-terminal assembly domain of alpha. For detailed functional mapping, Ala was substituted for 26 highly conserved amino acids around residues 40, 80 and 170 to 210. The alpha-point mutants were analyzed in vitro for their abilities to form dimers and to assemble beta beta' subunits. New types of assembly-deficient mutants were identified: alpha-R45A (having substituted Ala for Arg at residue 45) dimerized but did not assemble beta (and beta') subunits; and alpha-L48A showed a decreased level of alpha 2 beta subassembly formation, indicating that this region (residues 45 to 48) is responsible for beta-binding. Isolation of two mutants, alpha-K86A and alpha-V173A, both forming alpha 2 beta but not alpha 2 beta beta' complex, confirmed our previous conclusion that two separated regions participate in beta'-binding.

Survey on swine SINEs (PRE-1) as candidates for SSCP markers in genetic linkage analysis

Of 310 random cosmid clones, 216 were positive for PRE-1 sequences by Southern hybridization. Thirty nine sub-fragments positive for the PRE-1 sequences were cloned from independent cosmid clones, and sequenced, with 17 complete PRE-1 elements found. Seven PRE-1 loci were amplified by polymerase chain reaction using genomic DNA of 12 unrelated pigs as template. The amplified fragments were then subjected to an analysis of single strand conformation polymorphism, with all the loci being polymorphic.