[Bayesian forecasting of plasma vancomycin concentration using time-dependent pharmacokinetics]

A new prediction method of vancomycin (VCM) pharmacokinetics has been developed using the modified Bayesian forecasting method involved in time-dependent pharmacokinetics in clearance. We investigated to evaluate the usefulness of this new prediction method compared with that of the ordinary Bayesian forecasting method. Serum samples, obtained from 4 patients at least 3 different days during the period for the VCM treatment were assayed by fluorescence polarization immunoassay. VCM pharmacokinetic parameters and predicted serum VCM concentrations were calculated using this new method and the ordinary one according to the one-compartment model. The precision of the predicted serum VCM concentrations by these two methods at the third experimental day were evaluated with the mean prediction error (ME), mean absolute prediction error (MAE) and root mean squared error (RMSE). The most precise and least-bias prediction of serum VCM concentrations were observed using this new prediction method (ME: -0.36 +/- 1.40, MAE: 1.13 +/- 0.82 and RSME: 1.37). The time-dependent decrease of VCM clearance was observed in all patients. Therefore, the fitting of the actual serum VCM concentrations obtained using the ordinary method produced less precise results than that using this new method. These results suggest the usefulness of this new prediction method considering time-dependent changes in VCM clearance.

Age-related reductions in number and size of anterior horn cells at C6 level of the human spinal cord

We examined numbers and sizes of anterior horn cells (AHCs) of the human spinal cord at C6 level with aging process. Spinal cords were obtained from twenty-four male cadavers, age ranged from 41 to 97 years without any accompanying pathological changes of the spinal cord. For quantitative investigation of the AHCs, spinal cord segments were embedded in celloidin after secondary fixation and dehydration; sections (20 microns thick) were stained with luxol fast blue-periodic acid-Schiff-hematoxylin and Klüver-Barrera methods; the neuronal number, the cell body area and the perimeter of AHCs in the gray matter (equivalent to the Rexed's lamina IX) were counted and measured using a combination of a microscope with a drawing tube, a digitizer and a computer at 400 times magnification. A marked reduction in number of AHCs was found in the aged subjects. Similarly, there were significantly age-related decreases in the cross-sectional area and perimeter of AHCs at C6 segment of the spinal cord. These findings indicate that the reduction in number and size of AHCs in the human spinal cord is associated with degenerative neuronal changes and loss of motoneurons during aging process.

Molecular characterization of feline immunodeficiency virus genome obtained directly from organs of a naturally infected cat with marked neurological symptoms and encephalitis

Feline immunodeficiency virus (FIV) was first isolated from cats with immunodeficiency syndrome. Recently, neurological abnormalities and brain lesions were shown in cats infected with FIV. To investigate the FIV genome associated with central nervous system (CNS) lesions, proviral DNA sequences from the V3-V6 region of the FIV env gene were directly amplified from uncultured necropsy tissues of a 2-year-old naturally FIV-infected cat with marked neurological symptoms and encephalitis. By in situ hybridization, FIV RNA was detected mainly in the astrocytes. Fifteen clones isolated from cerebrum, bone marrow and lymph node samples showed only a small number of mutations or deletions in this region. A representative clone, JN-BR1, was distantly related to the previous Japanese strain (TM2) belonging to the subtype B. However, it was relatively close to the Petaluma strain which is known to infect feline brain-derived culture cells and induce brain lesions in inoculated cats. By phylogenetic analysis, the JN-BR1 strain was placed in subtype A that included Petaluma strain and several other American and European strains. The JN-BR1 strain derived from brain with encephalitis in this study and the Petaluma strain may share a common genetic structure that is related to their neuropathogenicity.

Direct detection of Streptococcus mutans in human dental plaque by polymerase chain reaction

Streptococcus mutans is an etiological agent in human dental caries. A method for the detection of S. mutans directly from human dental plaque by polymerase chain reaction has been developed. Oligonucleotide primers specific for a portion of the dextranase gene (dexA) of S. mutans Ingbritt (serotype c) were designed to amplify a 1272-bp DNA fragment by polymerase chain reaction. The present method specifically detected S. mutans (serotypes c, e and f), but none of the other mutans streptococci: S. cricetus (serotype a), S. rattus (serotype b), S. sobrinus (serotypes d and g), and S. downei (serotype h), other gram-positive bacteria (16 strains of 12 species of cocci and 18 strains of 12 species of bacilli) nor gram-negative bacteria (1 strain of 1 species of cocci and 20 strains of 18 species of bacilli). The method was capable of detecting 1 pg of the chromosomal DNA purified from S. mutans Ingbritt and as few as 12 colony-forming units of S. mutans cells. The S. mutans cells in human dental plaque were also directly detected. Seventy clinical isolates of S. mutans isolated from the dental plaque of 8 patients were all positive by the polymerase chain reaction. These results suggest that the dexA polymerase chain reaction is suitable for the specific detection and identification of S. mutans.

Analysis of mandible of newly developing strain of Japanese white rabbit (Nib:JWNS)

In the present paper, we applied analysis of the mandible to a new strain of Japanese White rabbit being developed (Nib: JWNS), at 5th and 8th generations (F5 and F8), and evaluated the process of establishment, making comparison with the parent colonies (I, K and L), and other established JW colonies (A, E, O and R). The mandibles were measured at 12 sites and the data obtained were calculated by principal component analysis and discriminant analysis. As a result of principal component analysis, the parent colonies were found to be close to one another with intermediate size of the mandible and height of condyloid and angular processes, but in F5 and F8 the mandibles were slightly shorter in height and different from those in the parent colonies. On the other hand, results of discriminant analysis revealed that mandibles were discriminated correctly 100% in colonies A, O and R, and 90% in E and I. Colonies A, O, R, E and I were therefore regarded as established strains. In the developing colonies, the discriminant rate was 70% in F5 and 80% in F8. One mandible from F5 and two from F8 were wrongly classified to the parent colony L, which was the lowest discriminant rate among the colonies examined (61.5%). The results of both statistical analyses suggest that the JWNS are almost established at 8th generation as a new strain.

Apoptosis in the aged dog brain

Apoptosis similar to that seen in Alzheimer's disease patients was found in the brain of aged dogs by the TUNEL method of detecting in situ DNA fragmentation. Apoptosis was observed in both neurons and glial cells, and was morphologically characterized by round and swollen cytoplasm and aggregated nuclear chromatin, although these changes were slight. Neurons and astrocytes in the gray matter and oligodendrocytes in the white matter were affected. The number of ApopTag-positive brain cells increased slightly with age, but was not correlated to the number of senile plaques. A good correlation between the number of ApopTag-positive cells and the dementia index was clearly found. The present study indicates that brain cell apoptosis could account for dementia in aged dogs and suggested that aged dogs may be useful as a simplified animal model for Alzheimer's disease in man.

Immunohistochemical characteristics of the constituents of senile plaques and amyloid angiopathy in aged cynomolgus monkeys

In this study, we immunohistochemically examined the several constituents of senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in aged cynomolgus monkeys. Apolipoprotein E (apoE) deposited in all mature plaques and CAA, and in half of the diffuse plaques. Alpha-1-antichymotripsin (alpha ACT) deposited in half of the mature plaques and in one third of the CAA. Amyloid precursor protein (APP), ubiquitin (Ub), and microtubule-associated protein-2 (MAP-2) accumulated in the swollen neurites of mature plaques. Glial fibrillary acidic protein (GFAP) was detected in the astrocytes and their processes surrounding the mature plaques. Tau was detected in neither the SPs nor CAA. Therefore, mature plaques involved extracellular A beta, apoE, and alpha ACT, and also astrocytes and swollen neurites. However, diffuse plaques involved only extracellular A beta and apoE. Since these features, except for tau, were consistent with those in humans, this animal model will be useful for studying the pathogenesis of cerebral amyloid deposition.

Distribution of amyloid bodies in the aged human vestibulocochlear nerve

We tried to elucidate the localization and distribution of amyloid bodies (Corpora amylacea) in the human vestibulocochlear nerve stained with luxol fast blue-periodic acid Schiff-hematoxylin using of a combination of an image analyzing computer system and a microscope fitted with a drawing tube. After having observed each section of the vestibulocochlear nerve from the brain stem to the fundus of the internal auditory meatus, we counted the numbers of amyloid bodies in three different parts for each of three corpses, and measured the areas. We found that amyloid bodies of the vestibulocochlear nerve are concentrated to the limiting glial portion of the nerve more than to the nerve parenchyma, and amyloid bodies are not seen in the vestibulocochlear nerve peripheral to the transitional zone. Our quantitative trial proved that the amyloid body was larger in the 8th decade than in the 6th or 7th decade of life.

Protective effect of recombinant interferon (IFN)-alpha/beta on MHV-2cc-induced chronic hepatitis in athymic nude mice

The protective effects of recombinant IFN-alpha/beta on MHV-2cc-induced chronic and persistent hepatitis in athymic nude mice were examined. The mice intraperitoneally (ip) inoculated with MHV-2cc at day 0 of experiment were divided into 4 groups. Three of them were administered ip with recombinant IFN-alpha/beta at a daily dose of 1 x 10(3) IU from -1 (-1D-group), 0 (0D-group), and +1 day of experiment (+1D-group), respectively, for 3 consecutive weeks. The remaining one (control group) was given 0.1 ml/mouse of PBS from +1 day of the experiment in the same way. Three mice in each group were killed at 1, 2 and 3 weeks post inoculation (WPI) with MHV, respectively. The liver virus titer in the control group increased gradually and maintained high levels throughout the experimental period. In the IFN-groups, particularly in the -1D- and 0D-groups, the virus titers were significantly lower than that in control group. Histopathologically, focal hepatic lesions were observed at 1WPI and large irregular inflammatory lesions developed at 3WPI in the control group. Similar but somewhat less severe lesions were observed in the +1D-group. In the -1D- and 0D-groups, lesions were not observed at 1WPI and only small organized lesions with mononuclear cell infiltration were seen at 3WPI. In conclusion, it was clarified in the present study that the progression of MHV-2cc-induced chronic hepatitis in athymic nude mice was effectively prevented by extrinsic IFN-alpha/beta when administered from -1 day and 0 day of the virus infection.

[An outbreak of influenza A (H3N2) in a nursing home]

In the nursing home belonging to our hospital, an outbreak of influenza A (H3N2) occurred in January 1995, and we studied 23 elderly residents with influenza A infection. Twenty three residents with influenza A (8 males and 15 females) ranged in age from 67 to 95 years (average 83.1 years), 91.3% of them were bedridden. And all had underlying medical conditions with neurologic, cardiac, orthopedic, being the most frequent. The most common complaints were fever (100%), followed by cough (95.7%), sputum (60.9%), but sore throat was significantly less frequent. Influenza A virus was isolated from throat swab specimens from 6 of 18 ill patients. Fourteen persons were hospitalized and 2 of them had pneumonia, but nobody died. The levels of CRP, WBC were significantly high in the influenza group, as compared to the non influenza group. So this result suggested that influenza A infection among elderly subjects was apt to cause bacterial infection such as bronchitis and pneumonia. This outbreak was caused by contact from the staff to residents, so we think the health care of the staffs and prevention of influenza should be a high priority in nursing homes.

Hepatitogenicity of three plaque purified variants of hepatotropic mouse hepatitis virus, MHV-2 in athymic nude mice

Hepatitogenicity of 3 plaque purified variants of hepatotropic mouse hepatitis virus, MHV-2 were examined in athymic BALB/c-nu/nu mice up to 9 weeks post infection (9WPI). All of the MHV-2S- and MHV-2M-infected mice died with severe acute hepatitis in 3WPI. On the other hand, MHV-2L-infected mice did not die until 9WPI and showed signs of slow-developing chronic hepatitis with persistent infection under low serum virus neutralizing antibody titers. This suggests that MHV-2L-infected athymic nude mice may be useful as a new model of chronic viral hepatitis.

Factors affecting induction of neurological disorders in mice by paralysis-inducing Friend-related PVC viruses

Our previous studies showed that the passage of the Friend virus complex through rats generated variant MuLVs, designated PVC111, PVC211, PVC321 and PVC441, that induced neurological disorders associated with tremor and paralysis. In this study, we tested the pathogenicity of four different PVC viruses in mice. Although histopathological studies revealed spongiform degeneration in the spinal cords of NFS mice infected with each PVC virus, only PVC441 frequently induced tremor and paralysis. After a long latency, all of these viruses induced leukemia associated with severe anemia. Further studies with PVC441 revealed dose- and age-dependence for tremor induction. In contrast to NFS mice, BALB/c, DBA/2 and C57BL/6 mice infected with PVC441 virus showed no neurological symptoms, although the virus could be isolated from the tissues of central nervous system. Despite the absence of neurological symptoms, a high degree of neuronal degeneration in the lumbar spinal cord was found in PVC441-infected BALB/c mice. A low degree of neuronal degeneration was found in PVC441-infected DBA/2 or C57BL/6 mice. Genetic crosses of these resistant mice with susceptible NFS mice indicated that resistance to tremor induction by PVC441 was dominant in all mouse strains and suggested that various host genes may control the susceptibility of mice to tremor induction by PVC441 virus.

Immunohistochemical study on the deposition of apolipoprotein E in cerebral and islet amyloidoses in cynomolgus monkeys (Macaca fascicularis)

To investigate the role of apolipoprotein E (apo E) in amyloidoses of cynomolgus monkeys, the localization of apo E in cerebral amyloid, including senile plaques and cerebrovascular amyloid, and in islet amyloid was examined immunohistochemically. Mature types of senile plaques with amyloid deposits and cerebrovascular amyloid showed intense immunoreactivity to both antisera to apo E and amyloid beta protein (A beta). In contrast, diffuse plaques without obvious Congophilic amyloid showed weak immunoreactivity to antiserum to apo E, but intense reactivity to antiserum to A beta. In addition, the number of these apo E-positive diffuse plaques was small compared with that of A beta-positive plaques. On the other hand, diabetic islet amyloid that was negative with A beta, reacted intensely with antiserum to apo E. These findings suggest that apo E plays an important role in amyloid fibril formation in several types of amyloidoses.

Demonstration of the nasal septal branches of the sphenopalatine artery by use of a new intravascular injection method

We injected a new injection material into the external carotid artery using a new method, which led to the successful demonstration of the nasal septal branches of the sphenopalatine artery in human cadavers. The result shows the trunk of the artery divided into three main branches, the upper two of which run toward Little's area. We believe that the knowledge of septal branches, shown in a photograph, is very useful, not only for nasal treatment, but also for anatomic demonstration to students.

Senile plaques in very aged cats

Senile plaques were found in the cerebral cortices of three very aged cats (more than 18 years old). The plaques consisted of a coarse assembly of silver staining-positive materials, and was morphologically different from the well-known classical, primitive, and diffuse plaques. Congophilic amyloid angiopathy was observed in a few cortical arterioles of the oldest cat (20 years old). The senile plaques and a few cortical blood vessels were immunopositive for amyloid beta-protein (A beta). A beta-positive materials were also sparsely distributed in the cortical neuropil but did not form senile plaques there. These findings should help to clarify the development of senile plaques and the early stage of A beta deposition.

A retrospective study of canine senile plaques and cerebral amyloid angiopathy

Epidemiologic and morphologic features of canine senile plaques (SPs) and cerebral amyloid angiopathy (CAA) were examined in 69 necropsied dogs. Dogs having only SPs (diffuse plaques) frequently suffered from malignant neoplasms, and their mean age was significantly lower than that of dogs with CAA only. Morphologically, diffuse plaques showed wide distribution compared with amyloid plaques or CAA and were predominantly concentrated in the frontal cortex. We were unable to find any significant relationship between the severity of the SPs and individual age. These findings may indicate that the occurrence of canine SPs is not strictly associated with aging only and that additional factors are related to the occurrence of SPs, especially diffuse plaques.

Nucleotide sequence of the SrRNA gene and phylogenetic analysis of Trichomonas tenax

The small subunit ribosomal RNA (SrRNA) gene of Trichomonas tenax ATCC30207 was amplified by PCR and the 1.55-kb product was cloned into plasmid vector pUC18. Four clones were isolated and sequenced. The insert DNAs were 1,552 bp long and their G+C contents were 48.1%; three of them had exactly the same DNA sequences and one had only one nucleotide change. A representative SrRNA sequence was analyzed and a phylogenetic tree was estimated by the neighbor-joining (NJ) method. Among the protists examined, T. tenax was placed as the closest relative of Tritrichomonas foetus, as expected from the traditional taxonomy. The total homology between the two SrRNA sequences was 89.2%.

Transformation of a laser beam intensity profile by a deformable mirror

We developed a deformable mirror with nine actuators for transformation of a laser beam intensity profile. A circular-cross-section Gaussian beam was successfully transformed into a rectangular-cross-section beam by the deformable mirror with conservation of spatial coherency.

In vitro induction of apoptosis of developing brain cells by 5-azacytidine

We had found that 5-azacytidine (5Az), a cytidine analogue, could produce apoptosis of fetal developing neuronal cells on the day after injection of the agent into dams by the i.p. route at 11 days of gestation. To make a further understanding of the phenomenon by comparing the results between the in-vivo and in-vitro system, this study was carried out. Entire cephalic parts of the fetuses were collected aseptically at days 11 of gestation and a mixed culture, consisting of neuronal and mesenchymal cells, was established after one week of incubation. The silver-staining revealed pyknotic nuclei and loss of dendrites of neuronal cells in the lower (5 micrograms/ml) dose of the 5 Az-added group. SEM showed shrinkage of the cell body and blebbing formation on the cell surface. TEM evoked margination, segmentation and complete condensation of the nuclear chromatin. Scattered positive signals identical to the apoptotic cells and aggregated fragmented DNA were detected by the TUNEL method. Treatment of higher doses of 5Az (50 and 500 micrograms/ml), however, induced necrosis of both neuronal and mesenchymal cells, light- and electron-microscopically. On the contrary, the control group (0 microgram/ml) showed normal development of neuronal cells and very few positive signals of physiological apoptosis. It was concluded that 5Az could induce apoptosis of developing neuronal cells at lower doses, but necrosis of a wider cell population at higher doses. Involvement of hypomethylation, an important biochemical function of 5Az, in apoptosis was also speculated.

Morphometric development of the human fetal auditory system: inferior collicular nucleus

The development of the human inferior collicular nucleus was studied on serial sections of the brains of 9 fetuses at 12-34 weeks of gestation and an adult of 63 years using an electronic planimeter with a computer. Morphometric analysis of the development of the inferior collicular nucleus showed that its development accelerates after 18 weeks of gestation in terms of the columnar volume and length, size of neurons and circularity ratio. Large-sized neurons 2-3 times the area of small-sized neurons appeared after 18 weeks of gestation. The ratio of large neurons to the total ranged between 3 and 6% in the inferior collicular nucleus. The development of the inferior collicular nucleus was similar to that of the ventral cochlear nucleus and the medial superior olivary nucleus.

Spontaneous vascular mineralization in the brain of horses

Cerebral vascular mineralization was found in 12 (60%) of 20 3- to 10-year-old healthy horses collected at an abattoir. It was variable in degree and occurred mostly in the pallidal arteries showing two types of lesions; small globoid bodies along capillaries, and amorphous deposits in the wall of arterioles, small- or medium-sized arteries and veins. Both types were strongly positive for periodic acid-Schiff reaction, and weakly positive for von Kossa's and Berlin blue stains. Elemental analysis of the deposit revealed the presence of large amounts of aluminum, moderate amounts of phosphorus, zinc, calcium and iron, and a small amount of sodium.

Carboxyl end-specific monoclonal antibodies to amyloid beta protein (A beta) subtypes (A beta 40 and A beta 42(43)) differentiate A beta in senile plaques and amyloid angiopathy in brains of aged cynomolgus monkeys

Senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in the brains of five aged (20-26 years old) cynomolgus monkeys were investigated immunohistochemically using two monoclonal antibodies (anti-A beta 40 (BA27) and anti-A beta 42(43) (BC05)) that can differentiate the carboxyl termini of amyloid beta protein (A beta) subtypes. In four of five animals, all types of SPs (i.e. diffuse, primitive, and classical plaques; DPs, PPs, and CPs, respectively) were identified by BC05. However, BA27 did not label DPs and stained only about one third of PPs and CPs, mainly labeling granular structures and cored portions, respectively. In CAA, lesions of cortical capillaries reacted to BC05 in four of five cases, but rarely and weakly to BA27 in two of five cases. On the other hand, lesions of parenchymal and meningeal arterioles were stained by both BA27 and BC05. These staining profiles of SPs in cynomolgus monkeys correspond well to those in humans, although there are two remarkable features in cynomolgus monkeys. First, BA27 stained PPs associated with granular structures. Secondly, capillary A beta reacted intensely to BC05 but only slightly to BA27. Despite these unique features, the results suggest that aged cynomolgus monkeys can be used to investigate the pathogenesis of A beta deposition in SPs and CAA.

Morphometric analyses and aging process of nerve fibers in the human spinal posterior funiculus

The aim of the present study is to evaluate the size and number of axons in the human spinal cord nerve fibers according to the aging process, and, after conducting morphometry of histology preparations at different ages, to show some of the effects of aging on those fibers. We examined thirty-eight human spinal cords which had been taken from cadaver specimens (25 males and 13 females) aged from 41 to 97 years. The spinal segments were embedded in celloidin and sections were stained with Luxol fast blue-periodic acid-Schiff-hematoxylin (LPH). Highly enlarged images with a square eyepiece grid and oil-immersion lens were used to count the myelinated axons and to measure the axon transverse area in a unit area of the posterior funiculus at C6 level, with the help of a microscope equipped with a drawing tube, an electronic optical planimeter and a computer. Significant age-related linear decreases were found for all parameters. Our report may provide new information concerning the aging process of the human spinal cord. It revealed that a decrease in size and number of axons were one of the important changes occurring with the aging process in the human spinal posterior funiculus.

Tissue distribution of the DNA binding oncoprotein Maf during chicken development

To assess the normal function of the c-maf protooncogene product, we examined its tissue distribution during fetal growth and organogenesis of the chicken using an immunohistochemical technique. Nuclei of neuronal cells in the optic lobe and in the outer granular layer of the cerebral cortex were efficiently stained by anti-Maf serum throughout all developmental stages examined. In the lung, mesenchymal cells were stained intensely by the antiserum, with the most intense staining around embryonic day 15. During the embryonic period, nuclei of mesenchymal cells in the perichondrial and periosteal tissues as well as intestinal submucosa were also stained specifically by the antiserum. In addition, we detected substantial Maf immunoreactivity in nuclei of renal glomerular and proximal-tubular epithelial cells. These results suggest that c-Maf protein plays some important roles in the development of the central nervous system and tissues of mesodermal origin such as connective and renal tissues.