Laser frequency stabilization and control through offset sideband locking to optical cavities.

We describe a class of techniques whereby a laser frequency can be stabilized to a fixed optical cavity resonance with an adjustable offset, providing a wide tuning range for the central frequency. These techniques require only minor modifications to the standard Pound-Drever-Hall locking techniques and have the advantage of not altering the intrinsic stability of the frequency reference. We discuss the expected performance and limitations of these techniques and present a laboratory investigation in which both the sideband techniques and the standard, on-tunable Pound-Drever- Hall technique reached the 100Hz/square root(Hz) level.

Osmotic shock-induced neurite extension via activation of p38 mitogen-activated protein kinase and CREB.

Although it is known that sustained activation of classical mitogen-induced protein kinase (MAPK, also known as ERK) induced by nerve growth factor (NGF) plays an important role in the induction of neurite outgrowth, the role of p38 MAPK in neural cell function is still not clear. We developed two neuronal cell lines from PC12 cells, PC12m3 and PC12m32, in which NGF-induced neurite outgrowth is impaired and that show neurite outgrowth in response to hyperosmotic shock. The frequencies of neurite outgrowth of PC12m3 and PC12m32 cells induced by osmotic shock were approximately 10- and 12-fold greater, respectively, than that in PC12 parental cells. The p38 MAPK pathway inhibitor SB203580 but not the ERK pathway blocker U0126 inhibited the ability of PC12m3 and PC12m32 cells to induce neurite outgrowth in response to osmotic shock. Furthermore, expression of a nonactivable form of p38 but not that of wild-type p38 significantly blocked neurite outgrowth induced by osmotic shock. The extent of phosphorylation of p38 MAPK induced by osmotic shock in PC12m32 cells was much greater than that in PC12 parental cells. The upstream kinases MKK3 and MKK6, which phosphorylate and activate p38 MAPK, also showed higher levels in PC12m32 cells than in PC12 parental cells when treated with osmotic shock. Inhibition of p38 MAPK by SB203580 resulted in inhibition of the activity of the transcription factor CREB, which is activated by osmotic shock. These findings indicate that activation of CREB mediated by a p38 pathway distinct from the NGF signaling pathway may be required for neurite outgrowth.

Thermostabilization of a chimeric enzyme by residue substitutions: four amino acid residues in loop regions are responsible for the thermostability of Thermus thermophilus isopropylmalate dehydrogenase.

A chimeric 3-isopropylmalate dehydrogenase, named 2T2M6T, made of parts from an extreme thermophile, Thermus thermophilus, and a mesophile, Bacillus subtilis, was found to be considerably more labile than the T. thermophilus wild-type isopropylmalate dehydrogenase. In order to identify the molecular basis of the thermal stability of the T. thermophilus isopropylmalate dehydrogenase, 11 amino acid residues in the mesophilic portion of the chimera were substituted by the corresponding residues of the T. thermophilus enzyme, and the effects of the side chain substitutions were analyzed by comparing the reaction rate of irreversible heat denaturation and catalytic parameters of the mutant chimeras with those of the original chimera, 2T2M6T. Four single-site mutants were successfully stabilized without any loss of the catalytic function. All these four sites are located in loop regions of the enzyme. Our results strongly suggest the importance of these loop structures to the extreme stability of the T. thermophilus isopropylmalate dehydrogenase.

A stable intermediate in the thermal unfolding process of a chimeric 3-isopropylmalate dehydrogenase between a thermophilic and a mesophilic enzymes.

The thermal unfolding process of a chimeric 3-isopropylmalate dehydrogenase made of parts from an extreme thermophile, Thermus thermophilus, and a mesophile, Bacillus subtilis, enzymes was studied by CD spectrophotometry and differential scanning calorimetry (DSC). The enzyme is a homodimer with a subunit containing two structural domains. The DSC melting profile of the chimeric enzyme in 20 mM NaHCO3, pH 10.4, showed two endothermic peaks, whereas that of the T. thermophilus wild-type enzyme had one peak. The CD melting profiles of the chimeric enzyme under the same conditions as the DSC measurement, also indicated biphasic unfolding transition. Concentration dependence of the unfolding profile revealed that the first phase was protein concentration-independent, whereas the second transition was protein concentration-dependent. When cooled after the first transition, the intermediate was isolated, which showed only the second transition upon heating. These results indicated the existence of a stable dimeric intermediate followed by the further unfolding and dissociation in the thermal unfolding of the chimeric enzyme at pH 10-11. Because the portion derived from the mesophilic isopropylmalate dehydrogenase in the chimeric enzyme is located in the hinge region between two domains of the enzyme, it is probably responsible for weakening of the interdomain interaction and causing the decooperativity of two domains. The dimeric form of the intermediate suggested that the first unfolding transition corresponds to the unfolding of domain 1 containing the N- and C-termini of the enzyme, and the second to that of domain 2 containing the subunit interface.

Clinical study of niceritrol on serum lipids in the treatment of hyperlipidemia.

The effects of niceritrol, a nicotinic acid derivative, on the levels of HDL-cholesterol (HDL-Ch) and a mixture of VLDL- and LDL-Ch (VLDL- + LDL-Ch) were studied in hyperlipidemic patients. Serum total cholesterol (sTC) and serum triglyceride (sTG) were significantly reduced during niceritrol administration. Lipoprotein electrophoresis showed that niceritrol increased the alpha:beta ratio. HDL-Ch showed a significant increase of 12.5% by the 16th week of therapy. This increase was more marked in patients with lower pre-treatment HDL-Ch levels and significant in patients whose pre-treatment sTG levels were in excess of 200 mg/dl. Females displayed higher pre-treatment HDL-Ch levels (38.5 mg/dl) than males (30.6 mg/dl). However, niceritrol increased HDL-Ch significantly in both groups. At 16 weeks, the VLDL- + LDL-Ch level showed a significant decrease of 9.2%; the HDL-Ch:VLDL + LDL-Ch and HDL-CH:sTC ratios were significantly increased throughout niceritrol administration. Niceritrol is thought to be effective in preventing the development and progression of atherosclerosis because it raises the level of anti-atherogenic HDL-Ch and lowers the level of atherogenic VLDL- + LDL-Ch.

Crystallization and preliminary X-ray studies of a Bacillus subtilis and Thermus thermophilus HB8 chimeric 3-isopropylmalate dehydrogenase and thermostable mutants of it.

A new type of chimeric 3-isopropylmalate dehydrogenase (2T2M6T) was produced by expressing the fused gene of Bacillus subtilis and Thermus thermophilus. The enzyme shows heat stability intermediate between those of the parents. The crystal of the enzyme belongs to the space group of P3(2)21, with cell dimensions of a = b = 78.9 A and c = 158.9 A. Two thermostable mutants of the chimeric enzyme were prepared by site-directed mutagenesis and then crystallized.

Age-related decrease in plasma growth hormone: response to growth hormone-releasing hormone, arginine, and L-dopa in obesity.

Aging is associated with a reduction in plasma growth hormone (GH) secretion in non-obese subjects. To determine whether or not age-related changes in plasma GH secretion exist in obese subjects, we measured (a) plasma GH response to growth hormone-releasing hormone (GRH; 1 microgram/kg body wt), arginine (0.5 g/kg body wt), L-dopa (500 mg), and (b) plasma glucose, insulin, and free fatty acids (FFAs) in 26 fasted obese subjects of various ages ranging from 16 to 71 years. Only subjects with a body mass index (BMI; kg/m2) between 30.0 and 39.0 were studied. Six subjects were adolescents, 9 were in their 20s, and 11 were 30 years or older. The mean peak levels of plasma GH in response to GRH, arginine, and L-dopa in obese subjects were 11.3 +/- 2.1, 21.9 +/- 4.4, and 5.2 +/- 0.3 ng/mL in adolescents, 8.2 +/- 1.6, 9.1 +/- 1.5, and 3.1 +/- 0.6 ng/mL in those in their 20s, and 4.5 +/- 0.4, 7.3 +/- 1.4, and 2.8 +/- 0.3 ng/mL in those 30 years or older, respectively, showing a significant decrease in peak GH level with advancing age (P less than .05 to P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Very-low-calorie diet-induced weight reduction reverses impaired growth hormone secretion response to growth hormone-releasing hormone, arginine, and L-dopa in obesity.

To determine whether impaired growth hormone (GH) secretion in obese subjects is a consequence of obesity or a pre-existing pituitary-hypothalamic disorder, we measured (1) plasma GH response to growth hormone-releasing hormone (GRH; 1 microgram/kg body weight [BW]), arginine (0.5 g/kg BW), and L-dopa (500 mg); and (2) plasma glucose, insulin, and free fatty acids (FFA) in obese subjects before and after weight reduction due to very-low-calorie diet therapy using Optifast (240 kcal/d for 8 to 12 weeks). Body weight and body mass index (BMI) values before and after weight reduction were 87.2 +/- 4.1 kg and 34.5 +/- 0.9 kg/m2, and 67.8 +/- 2.7 kg and 27.0 +/- 0.4 kg/m2, respectively. GH response to GRH, arginine, and L-dopa in obese subjects was markedly impaired before weight reduction, whereas significantly increased responses were noted after weight reduction (P less than .01). Impaired integrated GH response to GRH, arginine, and L-dopa in obese subjects was significantly restored after weight reduction (P less than .01). Plasma glucose levels did not change, while plasma insulin and FFA levels decreased significantly after weight reduction (P less than .01, P less than .05). There was no significant correlation between integrated GH response to these three stimuli and plasma levels of glucose, insulin, and FFA, respectively. The reversibility of GH response to all three stimuli after weight reduction suggests that impaired GH secretion is a consequence of obesity rather than a pre-existing pituitary-hypothalamic disorder.

The epidemiology of human calicivirus/Sapporo/82/Japan.

Based on genome analysis of the RNA-dependent RNA polymerase region, it has been proposed that human caliciviruses (HuCV) can be classified into at least three genogroups: genogroup I is represented by Norwalk virus (NV), genogroup II by Snow Mountain agent (SMA) and genogroup III by HuCV/Sapporo/82/Japan (HuCV/Sa/82/J) virus. HuCV/Sa/82/J strain is genetically unique and more closely related to animal caliciviruses than are other known HuCVs, such as NV and SMA. HuCV/Sa/82/J strain was detected in four outbreaks of HuCV gastroenteritis occurring between 1977 and 1982 in an infant home in Sapporo. The HuCVs detected from these four outbreaks all showed a typical "Star of David" configuration by electron microscopy (EM), and they were identical antigenically and genetically. This strain has also been detected in other prefectures in Japan, as well as in the USA, UK, Saudi Arabia and Kenya. Seroepidemiological studies have shown a worldwide distribution of this virus, including Japan, USA, UK, Southeast Asia, Canada, China and Kenya. This virus has been circulating in Sapporo for at least 19 years (1977-1995). HuCV/Sa/82/J strain is thought to be one of the common causes of viral gastroenteritis worldwide. The HuCV/Sa/82/J strain has been detected mainly in infants. Age-related prevalence of antibody to this strain also shows that infections commonly occur in children less than 5 years old, although viruses in the NV and SMA genogroups commonly infect adults. The pattern of acquisition of antibodies to strain HuCV/Sa/82/J is similar to that of other common viral infections. HuCV/Sa/82/J strain is unique virologically and clinically among caliciviruses.

Phasic capillary pressure determined by arterial occlusion in intact dog lung lobes.

In six open-chest dogs, electrocardiogram- (ECG) controlled pulmonary arterial occlusion was performed during the control period and during the infusions of serotonin and histamine. A temporal series of instantaneous pulmonary capillary pressure and the longitudinal distributions of vascular resistance and compliance were evaluated in the intact left lower lung lobe. In the control period, we found a significant phasic variation of pulmonary capillary pressure (Pc) with the cardiac cycle. The ratio of arterial to venous resistances (Ra/Rv) was 6:4, and the ratio of arterial to capillary compliances (Ca/Cc) was 1:11. During the infusions of serotonin and histamine, Pc showed similar phasic variations, despite significant hemodynamic changes induced by these agents. Serotonin predominantly increased Ra, whereas histamine predominantly increased Rv. The ratio of Rv to the total resistance decreased significantly from 0.42 to 0.32 during the infusion of serotonin and increased significantly to 0.62 during the infusion of histamine. The data suggest that phasic Pc determined by ECG-controlled arterial occlusion reflects the pulsatility in the pulmonary microvascular bed under control conditions and after alterations of the pulmonary vascular resistance by serotonin and histamine.

Fas (APO-1/CD95) mRNA is down-regulated in liver regeneration after hepatectomy in rats.

The interaction of Fas (APO-1/CD95) and the Fas ligand system induces apoptosis. However, the role of the Fas/Fas ligand system in normal physiological liver cell death remains to be determined. Using northern blotting analysis, we investigated the role of Fas and Fas ligand mRNA expression in liver regeneration in rats until 14 days after partial hepatectomy. Partial hepatectomy led to a significant decrease in Fas mRNA levels at 2 h, with a further gradual reduction until 18 h. The minimum Fas mRNA levels persisted until 5 days after the surgery. Fas mRNA levels then increased markedly at 6 days, and gradually increased to the initial levels by 14 days after the surgery. However, partial hepatectomy did not affect the expression of Fas ligand mRNA levels. These findings suggest that Fas mRNA is down-regulated in liver regeneration after partial hepatectomy, and that when the original liver mass is gradually regenerating, Fas mRNA is again up-regulated to the initial levels.

Hepatocyte proliferation in rats after ventromedial hypothalamic lesions: immunoreactivity patterns of proliferating cell nuclear antigen (PCNA).

Ventromedial hypothalamic (VMH) lesions result in increased DNA content in the rat liver. However, little information is available concerning the proliferative activity and lobular distribution of different cell populations in VMH-lesioned rat liver. The aim of the present study was to quantitatively assess these parameters in VMH-lesioned rat liver by measuring proliferating cell nuclear antigen (PCNA) reactivity. We investigated to determine whether this mitotic response involves acinar zones 1, 2, or 3. Changes in immunohistochemical labeling indices in rat liver were measured with an antibody against PCNA until 7 days after VMH lesioning. The effects of hepatic vagotomy on proliferation were also examined. Proliferation of hepatocytes in acinar zones 1-3 began to increase on day 1, and reached a maximum at 3 days. The area of most intense proliferation progressively shifted from acinar zone 1 to zone 3 in several days. The proliferation was completely inhibited by hepatic vagotomy, indicating that VMH lesions induce cell proliferation in rat liver via hepatic vagus nerve activity. This study implicates the information available on neural factors which initiate hepatocyte proliferation.

Use of balloon-occluded retrograde transvenous obliteration with ethanolamine oleate for the treatment of hepatic encephalopathy in a cirrhotic patient with a large spontaneous splenorenal shunt.

We describe a technique for the treatment of hepatic encephalopathy in a cirrhotic patient with a large spontaneous splenorenal shunt. This large shunt was successfully occluded without severe complications by retrograde transrenal venous obliteration with ethanolamine oleate after balloon occlusion. This procedure may be an effective method to occlude a large spontaneous splenorenal shunt for the treatment of hepatic encephalopathy.

Ventromedial hypothalamic lesions induce the proliferation of gastrointestinal mucosal cells in the rat.

We reported recently that ventromedial hypothalamic (VMH) lesions increased the synthesis of DNA in the gastrointestinal tract of rats by the firing of vagus nerve activity, mainly via cholinergic receptor mechanisms. In the present study, we examined whether the mitotic response is due to proliferation of a cell population--mucosal, submucosal, or muscular layer. A monoclonal antibody to proliferating cell nuclear antigen (PCNA) has previously been shown to be capable of identifying proliferating cells. Samples of formalin-fixed gastrointestinal epithelium, taken before and after VMH lesioning, were immunostained with the anti-PCNA monoclonal antibody, and the labeling index (LI) was determined. To discriminate the effect of hyperphagia in VMH lesioned rats, we utilized the method of pair-feeding. Cell proliferation was examined by the PCNA-labeling technique 0, 1, 3, and 7 days after VMH lesioning. The increase in proliferation was confined to cells in the mucosa and did not involve the muscularis and serosa. Studies in control animals showed that the LI was higher in the small intestine than in other gut segments, and higher in the large intestine than in the stomach. The mean PCNA-LI began to increase at 1 day and continued to increase for 3 days, then decreased 7 days following the lesioning. Results indicate that the gastrointestinal mucosa is in a state of hyperproliferation after VMH lesioning.

Dehydroepiandrosterone (DHEA) facilitates liver regeneration after partial hepatectomy in rats.

In this study we investigated whether or not liver regeneration is facilitated by dehydroepiandrosterone (DHEA) after partial (70%) hepatectomy in rats. Treatment with DHEA (300 mg/kg body weight) did not cause any significant increase in the expression ratio of proliferating cell nuclear antigen (PCNA) in sham-operated controls; however, in partially hepatectomized rats it caused a significant increase in the ratio in hepatocytes 24 and 36 hr after hepatectomy. In partially hepatectomized rats, DHEA treatment significantly accelerated the restoration of liver 48, 60, and 72 hr after partial hepatectomy. The restoration rate in DHEA-treated hepatectomized rats at 72 hr was 1.3-fold greater than in partially hepatectomized controls. Treatment with androstenedione (300 mg/kg body weight), the first metabolite of DHEA, did not cause any significant increase in the expression of PCNA in either sham-operated controls or partially hepatectomized rats. These results indicate that DHEA itself promotes the liver regenerative process after partial hepatectomy in rats.

Comparisons of the pharmacokinetics and the leukopenia and thrombocytopenia grade after administration of irinotecan and 5-fluorouracil in combination to rats.

BACKGROUND: Irinotecan (CPT-11) has been used recently for the treatment of several cancers in combination with 5-fluorouracil (5-FU). Preliminary data on this combination therapy in humans demonstrated no drug interactions between CPT-11 (or its metabolite, SN-38) and 5-FU however, because there is so little information on the combination, the possibility for an interaction still exists. MATERIAL AND METHODS: CPT-11 and 5-FU were injected intravenously into rats and the pharmacokinetics of CPT-11 and SN-38 and alternations in blood cell count were investigated. RESULTS: In the group of rats administered 5-FU prior to CPT-11, the area under the concentration-time curve (AUC) of CPT-11 was approximately eight-fold larger compared with the group administered CPT-11 prior to 5-FU. On the other hand, the grade of leukocytopenia or thrombocytopenia was not significantly different among the two groups. CONCLUSION: In rats, the conversion of CPT-11 into SN-38 is possibly delayed by prior administration of 5-FU.

A child case of haemophagocytic syndrome associated with cryptococcal meningoencephalitis.

A previously healthy 12-year-old Japanese girl developed meningoencephalitis due to Cryptococcus neoformans. During the course of her illness she suffered persistent high fever, severe pancytopenia, hypercytokinemia and liver dysfunction. Laboratory findings, including results of a bone marrow examination, strongly indicated complication by haemophagocytic syndrome (HPS). The preceding cryptococcal infection was thought to be a cause of the HPS because no other viral or bacterial infection could be confirmed. The girl died of acute respiratory failure during the progressive course of HPS. This may be the first reported case of HPS due to cryptococcal infection in an otherwise healthy child.

Childhood multiple sclerosis: MR images and clinical variations in four Japanese cases.

We report four Japanese cases of multiple sclerosis (MS) starting during childhood. In three of them, onset occurred in the prepubertal period. Case 1 showed a rare clinical condition: the patient presented with Devic disease, and 2 years later she was complicated by chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). The other three cases had symptoms of gait disturbance, cerebellar signs, weakness of the extremities and impaired visual acuity. Headache was seen in Case 2 and medial longitudinal fasciculus (MLF) syndrome in Case 4. In Cases 2, 3 and 4, diagnoses were conclusively made by T2-weighted magnetic resonance imaging (MRI). MRI, brain stem auditory, visual and somatosensory evoked potentials are extremely useful for evaluating the clinical conditions of children with MS.

Empedopeptin (BMY-28117), a new depsipeptide antibiotic. II. Structure determination.

Structure of a new antibiotic, empedopeptin, has been determined. It is a cyclic depsipeptide composed of two mol of D-serine and one mol each of beta-hydroxytetradecanoic acid, L-arginine, D- and L-proline, L-3-hydroxyproline and D- and L-beta-hydroxyaspartic acid. The sequence of these moieties was established by partial hydrolysis and mass spectral analysis of the antibiotic.

Isolation of an aminoglycoside hypersensitive mutant and its application in screening.

An aminoglycoside hypersensitive mutant, Kp-126, was isolated from the aminoglycoside-resistant strain, Kp-8, of Klebsiella pneumoniae through selection using sorbistin, a non-aminocyclitol-aminoglycoside antibiotic. The mutant Kp-126 was approximately 100-fold more sensitive to sorbistin than the parent strain Kp-8. The mutant also showed hypersensitivity to various aminocyclitol-aminoglycoside antibiotics. K. pneumoniae Kp-126 was used in screening and a new aminoglycoside antibiotic, 3,3'-neotrehalosadiamine (BMY-28251), was discovered in the fermentation broths of soil isolate strain of Bacillus pumilus.