Complete inhibition of human immunodeficiency virus Gag myristoylation is necessary for inhibition of particle budding

Myristoylation of human immunodeficiency virus (HIV) Gag protein is essential for virus particle budding. Two reactions are involved; activation of free myristate to myristoyl-CoA and transfer of the myristoyl residue to the Gag N-terminal glycine. We have investigated the effects of triacsin C, an inhibitor of long chain acyl-CoA synthetase, on release of HIV Gag virus-like particle (VLP) produced using the recombinant baculovirus system. First, inhibition of acyl-CoA formation by triacsin C was confirmed using the membrane fractions of insect Sf9 cells as an enzyme source. Second, when HIV Gag protein was expressed in the presence of triacsin C (0-48 microM), Gag myristoylation was inhibited in a dose-dependent manner. Budding of Gag VLP, however, did not follow similar inhibition kinetics but appeared unaffected up to 24 microM, yet was completely abolished at 48 microM when the myristoylation of Gag protein was also completely inhibited. The "all-or-none" inhibition of Gag VLP budding suggests that although inhibition of acyl-CoA synthetase blocks the production of myristoylated Gag protein, only complete inhibition of Gag myristoylation prevents VLP budding. Thus, relatively few myristoylated Gag molecules are sufficient for plasma membrane targeting and VLP budding.

Applications of retrovirus-mediated expression cloning

We have recently established a novel expression cloning system using retroviral vectors. The system is based on a high-efficiency packaging cell line, BOSC23, and a simplified retroviral vector, pBabeX, carrying no selection marker. cDNA libraries, constructed in the pBabeX vector, are transiently transfected into BOSC23 cells. The supernatant contains more than 3X10(6)/mL, which would cover large complexities of cDNA libraries. The retrovirus stock gave 100% infection efficiency in NIH3T3 cells and 5-40% infection efficiency in various hematopoietic cell lines. In contrast to the conventional expression cloning system, in which it is necessary to transfect cDNA libraries transiently into particular cell types such as COS cells, retrovirus-mediated expression cloning allows us to transduce cDNAs into a wide variety of cell types. This method therefore makes it possible to select cells expressing a cDNA of interest by various functional assays. When combined with polymerase chain reaction (PCR)-driven random mutagenesis, this system is also useful in searching for mutations of various molecules that will result in alterations of their functions.

Induction of experimental bone metastasis in mice by transfection of integrin alpha 4 beta 1 into tumor cells

Cell adhesion receptors (eg, integrins and CD44) play an important role in invasion and metastasis during tumor progression. The increase in integrin alpha 4 beta 1 expression on primary melanomas has been reported to significantly correlate with the development of metastases. alpha 4 beta 1 is a cell surface heterodimer that mediates cell-cell and cell-extracellular matrix interactions through adhesion to vascular cell adhesion molecule (VCAM)-1 and to the IIICS region of fibronectin. To test the effects of alpha 4 beta 1 expression on tumor cell metastasis, Chinese hamster ovary cells were transfected with human alpha 4 cDNA. Whereas alpha 4-negative Chinese hamster ovary cells developed only pulmonary metastasis, alpha 4-positive Chinese hamster ovary cells developed bone and pulmonary metastasis in 3 to 4 weeks when injected intravenously into nude mice. Bone metastasis was inhibited by antibody against alpha 4 or VCAM-1. Expression of alpha 3 beta 1, alpha 6 beta 1, or alpha V beta 1 did not induce bone metastasis. Expression of alpha 4 beta 1 also induced bone metastasis in K562 human erythroleukemia cells injected into SCID mice. These results demonstrate that alpha 4 beta 1 can induce tumor cell trafficking to bone, probably via interaction with VCAM-1 that is constitutively expressed on bone marrow stromal cells.

Molecular cloning and functional characterization of a novel member of the C-C chemokine family

Chemokines play an important role in immune and inflammatory responses by inducing migration and adhesion of leukocytes. We have isolated a novel chemokine cDNA, designated CCF18, from a cDNA library of an IL-3-dependent murine pro-B cell line, Ba/F3. The cDNA encodes a protein structurally related to the C-C chemokine members. Among this family, C10 shows the highest homology to CCF18, and MIP-1 alpha also has a significant homology but to a lesser extent. CCF18 produced from COS cells induced chemotaxis and Ca2+ flux in CD4+ T cell clones. Moreover, prior administration of MIP-1 alpha desensitized the cells to CCF18. The CCF18 gene (Scya10) was mapped to a middle region of murine chromosome 11, where other genes for several C-C chemokine members are localized. These results clearly indicate that CCF18 is a new member of the C-C chemokine family. Since a high level of CCF18 mRNA is constitutively expressed in macrophage and myeloid cell lines, CCF18 may play a role in inflammatory processes.

Molecular cloning and functional characterization of a novel member of the C-C chemokine family

Chemokines play an important role in immune and inflammatory responses by inducing migration and adhesion of leukocytes. We have isolated a novel chemokine cDNA, designated CCF18, from a cDNA library of an IL-3-dependent murine pro-B cell line, Ba/F3. The cDNA encodes a protein structurally related to the C-C chemokine members. Among this family, C10 shows the highest homology to CCF18, and MIP-1 alpha also has a significant homology but to a lesser extent. CCF18 produced from COS cells induced chemotaxis and Ca2+ flux in CD4+ T cell clones. Moreover, prior administration of MIP-1 alpha desensitized the cells to CCF18. The CCF18 gene (Scya10) was mapped to a middle region of murine chromosome 11, where other genes for several C-C chemokine members are localized. These results clearly indicate that CCF18 is a new member of the C-C chemokine family. Since a high level of CCF18 mRNA is constitutively expressed in macrophage and myeloid cell lines, CCF18 may play a role in inflammatory processes.

Effects of Bordetella bronchiseptica dermonecrotizing toxin on bone formation in calvaria of neonatal rats

The effects of Bordetella bronchiseptica dermonecrotizing toxin on bone formation were investigated using a purified toxin preparation. Single injection of 4.3 ng of the toxin into the subcutaneous tissue overlying the calvariae of neonatal rats necrotized periosteum of parietal bone and degenerated osteoblasts within two days. Nine days after the injection, the lesion of the bone tissue became severe; the bone matrix became thin and fragmented. These observations indicate that dermonecrotizing toxin without other factors produced by the organisms impairs bone formation.

Different migration patterns of antigen-presenting cells correlate with Th1/Th2-type responses in mice

Antibodies are produced when antigen-presenting cells (APC) pulsed with an antigen are injected intravenously (i.v.) into BALB/c mice, but subcutaneous (s.c.) injection of such APC causes delayed-type hypersensitivity (DTH). To identify the anatomic sites where T and B cells are activated, we labelled splenic dendritic cells (DC) with a fluorochrome, PKH 26, injected them i.v. or s.c., and used the label to locate them. When the DC were injected i.v., germinal centres in the spleen were hyperplastic on day 1. Most DC moved to T-dependent areas of the white and red pulp on day 1 and remained there at least until day 5, but no DC migrated into the lymph nodes. When the DC were injected s.c., they were in the sinus on day 1 and had entered T-dependent area of draining lymph nodes only by day 3; hyperplasia of germinal centres in the spleen and migration of DC into the spleen were not found. We used the polymerase chain reaction (PCR) to study which mice had spleen cells and lymph node cells that produced the cytokines interleukin (IL)-2, IL-4, IL-10, and interferon-gamma (IFN-gamma). In the sensitization phase, day 1 after DC injection i.v., almost all IL-10 transcript was found in spleen cells, but after DC injection s.c., IL-2 message was most abundant in lymph node cells. The expression of mRNA for IL-4 and IFN-gamma in mice that received DC i.v. was not different from that in mice that received DC s.c. in this phase. Immunohistochemical staining showed that cells stained for IL-10 were in the T-dependent area of the spleen from mice that received DC i.v. 1 day after the injection. Three days after the injection of DC i.v., cells stained for IL-10 were in the germinal centres as well. The number of such cells in the spleen of mice that received DC i.v. was significantly more than that in mice that received DC s.c. IL-10 may be important in development of TH2 response.

A molecular determinant of human immunodeficiency virus particle assembly located in matrix antigen p17

We report single-point mutations that are located in the matrix protein domain of the gag gene of human immunodeficiency virus type 1 and that prevent Gag particle formation. We show that mutations of p17 that abolish human immunodeficiency virus particle assembly also prevent the dimerization of p17 protein, as measured directly by a protein-protein binding assay. In the three-dimensional structure of p17, mutations that abolish dimerization are located in a single alpha helix that forms part of a fingerlike projection from one side of the molecule. Peptides derived from this region of p17 also reduce the level of p17 dimer when they are added to p17-expressing cells and compete for p17 self-association when present in protein-protein binding assays. We propose that the dimerization of the Gag precursor that occurs by the interdigitation of alpha helices on adjacent matrix molecules is a key stage in virion assembly and that the prevention of such an interaction is the molecular basis of particle misassembly.

The use of an ileostomy connector to diminish the frequency of defecation prior to ileostomy closure in patients with a pelvic pouch

A new method for allowing stool passage into the pelvic pouch before ileostomy closure to verify the defecation state and diminish stool frequency is reported herein. This was accomplished by fitting an ileostomy connector connecting the proximal and distal openings of the diverting loop stoma. The ileostomy connector was initially in place for 6 h a day, the length of time being gradually increased until it was able to be left in for 24 h a day over a 3-month period. The calculated daily frequency of stools decreased from 24 to 6 or 7 times, and the mean daily frequency immediately after ileostomy closure was 6.5 times. Physiological study also showed an improvement, with squeeze pressure increasing from 35 cmH2O to 116 cmH2O and the maximum tolerated volume increasing from 35 ml before, to 90 ml 3 months following the use of an ileostomy connector. Thus, we conclude that an ileostomy connector may be useful to predict postoperative functional outcome and its complications, and to diminish the frequency of defecation before ileostomy closure in patients with a covering loop stoma.

Morphometry on proximal tubule of the kidney in rat pups from uninephrectomized mothers

Effects of maternal uninephrectomy in rats, which was performed on day 5 of gestation, on development of proximal renal tubule of the pups were morphometrically investigated. One day after birth, both the proximal tubular length per unit volume (1 mm3) of whole kidney and total proximal tubular volume in the neonates from uninephrectomized mothers were significantly larger than those in the neonates from sham-operated mothers. Six weeks after birth, no significant differences in parameters of the kidney were observed between the pups from uninephrectomized and sham-operated mothers. These results suggest that maternal uninephrectomy in the rat accelerates the development of proximal renal tubule in the fetus and that the renotropic activity is not lasting during postnatal development of the kidney.

Malignant schwannoma of the liver

Malignant schwannoma is the most common soft tissue sarcoma in adults, but primary schwannoma of the liver is extremely rare. We report an autopsy case of malignant schwannoma of the liver in a 63-year-old man. The tumor involved almost the entire right lobe of the liver. Microscopically, it was composed of moderately pleomorphic spindle cells with hyperchromatic nuclei with mitotic figures. The spindle cells were stained positively with antibodies to both S-100 protein and vimentin. Necrosis was found in the primary tumor. Only four other cases of malignant schwannoma of the liver were found in a review of the literature. Pertinent features of these tumors are discussed.

Plasma insulin and blood pressure in normotensive Japanese men with normal glucose tolerance

OBJECTIVE

To determine whether blood pressure within the normal range is associated with plasma insulin concentration in a Japanese population with normal glucose tolerance.

METHODS

We studied 491 normotensive Japanese men with normal glucose tolerance, who had never been treated with antihypertensive medications. Plasma glucose and insulin response during a 75-g oral glucose-tolerance test, blood pressure, body mass index, serum lipids, alcohol consumption and smoking status were obtained. The subjects were divided into quartiles according to mean blood pressure level (< 79, 79-84, 85-91 and > or = 92 mmHg). To eliminate possible confounding factors, analysis of covariance was also performed.

RESULTS

In univariate analyses the plasma insulin response after an oral glucose load, especially after 60 min, was significantly related to blood pressure level. Plasma glucose was related to blood pressure level only at fasting. When adjusted for age, body mass index, plasma glucose response and alcohol consumption, plasma insulin concentrations after 30 and 60 min in the highest quartile were significantly higher than those in the lowest quartile.

CONCLUSIONS

Blood pressure was significantly and independently related to plasma insulin level after an oral glucose load in normotensive Japanese men with normal glucose tolerance. The results suggest that the relationship between blood pressure and insulin resistance already exists in a prehypertensive state even in a lean Asian population.

Mortality of inhabitants in an area polluted by cadmium: 15 year follow up

OBJECTIVE

To assess the influence of environmental exposure to cadmium (Cd) on long term outcome of inhabitants living in an area polluted by Cd.

METHODS

A follow up study for 15 years (from 1974-5 to 1991) was carried out on 2408 inhabitants (amounting to 95% of the target population, 1079 men and 1329 women) of the Kakehashi River basin in Ishikawa Prefecture, Japan. These inhabitants had been the subjects of the health impact survey in 1974-5 to evaluate (by measurement of urinary retinol binding protein (RBP)) renal dysfunction induced by Cd. Analysis of mortality was performed by dividing subjects into a urinary RBP positive (> or = 4 mg/l) group and RBP negative (< 4 mg/l) group.

RESULTS

After adjustment for age with Cox's proportional hazard model, RBP > or = 4 mg/l showed a significant relation to mortality in both sexes. At this time, the mortality risk ratio of the RBP positive to negative group was 1.71 in the men and 1.42 in the women. When the SMRs according to causes of deaths in the RBP positive group were compared with those of the RBP negative group or the overall Japanese population increases of SMR for cardiovascular diseases, especially heart failure, and renal diseases were found in both sexes.

CONCLUSION

These results suggest that the prognosis of the exposed inhabitants with renal tubular dysfunction is unfavourable, and these increases of mortality are due to heart failure and renal diseases.

Comparative study on mortality patterns in Japan and China

On the basis of the 1990 Chinese death notice data and 1990 Japanese populations vital statistical materials, the mortality patterns and proportions of individual causes of death in the two countries were compared. In both sexes, the mortality rates were the highest in almost all age groups in Chinese rural areas followed by urban areas and Japan. In Japan and in Chinese urban areas, malignant neoplasms cardiovascular diseases and cerebrovascular diseases were the major causes of death, with these three making up about 60% of the total. In Chinese rural areas, these three conditions were responsible for 43% of all deaths, a considerably lower figure as compared to those in the other two areas, and the mortality rates for infectious diseases and accident/suicide were higher than those in the other two areas. Of the three major adult diseases, cerebrovascular diseases were found to be especially frequent in both Chinese urban and rural areas. On the other hand, ischemic heart disease was found at comparable levels in Japan and China and the rate was lower than in other developed countries. Site-specific mortality rates for malignant neoplasms were characterized by high rates for lung, liver and esophageal cancers in China. The mortality rates for bronchitis in both Chinese urban and rural areas were markedly higher than those in Japan These differences in mortality rates and proportions of individual causes of death between China and Japan are thought to be attributable to the differences in medical services and the level of risk factors for each disease.

Morphometry of the kidney in rat pups from uninephrectomized mothers

BACKGROUND

The present study was designed to explore whether maternal renal dysfunction affects fetal kidney development and if the effects are lasting during the postnatal development.

METHODS

Kidneys of 1-day-old and 6-week-old pups from mothers which were uninephrectomized on day 5 of gestation were studied.

RESULTS

One day after birth, both the number of immature glomeruli and average volume of mature glomeruli of the neonates from uninephrectomized mothers were significantly larger than those from sham-operated mothers. Six weeks after birth, no significant differences in parameters of the kidney were observed between the pups from uninephrectomized and those from sham-operated mothers. Furthermore, blood urea nitrogen (BUN) concentration in adult female rats was determined at various days after uninephrectomy. BUN concentration in uninephrectomized rats was significantly higher than that in sham-operated ones.

CONCLUSIONS

These results suggest that the fetal kidney development is accelerated by the elevated BUN level following maternal uninephrectomy and that the renotropic activity does not last during the postnatal developmental period.

A multicenter, randomized, controlled trial of intravenous gamma globulin therapy in children with acute Kawasaki disease

We studied the effect of intravenous, polyethyleneglycol-treated, human immunoglobulin, administered at 200 mg/kg per day (group A: n = 147; male 86, female 61; age < 1 year, 50) or 400 mg/kg per day (group B: n = 152; male 87, female 65; age < 1 year, 52) for five consecutive days and compared it with freeze-dried, sulfonated human immunoglobulin [group C: n = 152; male 87, female 65; age < 1 year, 51), administered at 200 mg/kg per day for five consecutive days, on the prevention of coronary artery abnormalities in Kawasaki disease. Echocardiograms were interpreted blindly and independently. Proportions of 87.1%, 95.4%, and 82.3% in groups A, B, and C, respectively, had no coronary artery abnormalities. The confidence limits of difference between the proportions of groups A and C, groups B and C, and groups B and A were -4.4% and 10.4%, 7.8% and 15.9%, and 4.0% and 10.8%, respectively. Duration of fever and serum immunoglobulin G (IgG) levels were correlated with the prevalence of coronary artery abnormalities. We concluded that intravenous, polyethyleneglycol-treated, human immunoglobulin and freeze-dried, sulfonated human immunoglobulin had clinically equivalent effects on coronary artery abnormalities, and that five daily doses of 400 mg/kg of intravenous, polyethyleneglycol-treated, human immunoglobulin is more effective than that of 200 mg/kg gamma globulin.

[A study of thyroid hormone levels of inhabitants of the cadmium-polluted Kakehashi River basin]

We compared thyroid hormone levels of inhabitants (19 men and 16 women) of the cadmium (Cd)-polluted Kakehashi River basin in Ishikawa Prefecture, with those of subjects (23 men and 47 women) living in a non-polluted area. In addition, we investigated the relationships between the thyroid hormone levels and indices of renal dysfunction induced by Cd exposure. The following results were obtained: 1) The free T4 level of females was significantly lower than that of controls. 2) The T3 level of inhabitants of both sexes was significantly higher than that of controls. 3) The level of free T4 among females became lower with the increases of urinary beta 2-microglobulin (beta 2-MG), urinary protein, urinary sugar, urinary amino acids and serum creatinine (Cr) levels, and with decreases of creatinine-clearance (CCr) and %TRP. 4) We could not find any relationship between the increase of T3 and the indices of renal dysfunction induced by Cd exposure in either sex.

[Endocrine chemotherapy for prostatic cancer]

We carried out a randomized joint study on endocrine therapy and endocrine chemotherapy for prostatic cancer at our department and 17 affiliated institutions. Of 80 patients entered, 39 patients were treated with chlormadinone acetate alone (group A) and 41 patients were treated with chlormadinone acetate in combination with UFT (group B). After excluding 10 inappropriate patients, Stage C was observed in 14 patients in group A and 13 in group B, and stage D in 20 patients in group A and 23 in group B. Side effects were observed in 8.8% (3/34) in group A and 22.2% (8/30) in group B without a significant difference. The anti-tumor effects (response rate) and clinical effects with respect to each item did not significantly differ between the two groups. The non-recurrence rate and survival rate were significantly higher in group B than in group A. These findings suggest the usefulness of endocrine chemotherapy using UFT.

Murine granulated metrial gland cell population in beige (bg/bg) and SCID (scid/scid) genotypes

Morphology of granulated metrial gland (GMG) cell, a uterine natural killer (NK) cell, was reported to be normal in pregnant uteri of NK cell-deficient mice and T-cell- and B-cell-deficient mice, but little is known about the number of GMG cells. To determine whether the number of GMG cells is influenced by such mutations, their number in the bg mice (genotype C57BL/6J-bg/bg) and SCID mice (genotype C.B-17/Icr-scid/scid) was compared to that of control mice on day 12 of gestation. GMG cells in these mutant mice were normal in number. Thus, the present results support the previous reports that GMG cells can differentiate normally in bg mice and that the GMG cell differentiation is not affected by functional T- nor B-cells.

[A case report of infant botulism without a history of honey ingestion]

A 66-day-old female with infant botulism is reported. She was admitted to our hospital with respiratory failure. Laboratory examinations detected botulinal toxin type A in her feces. This was the first case with no history of honey ingestion among the 13 cases of infant botulism reported in Japan. It is possible that other cases, in which honey had not been consumed, remain undiagnosed. Further studies may be needed to clarify the factors necessary to cause infant botulism.

Potassium/energy and phosphorus/calcium ratios reflect the quality of nutrition

A nutritional survey and questionnaire regarding dietary habits were administered to 649 men ranging in age from 35 to 64 years receiving a one-day health screening examination. First, comparisons of nutrient intake based on the nutrient rate of the Recommended Dietary Allowances for Japanese (RDA), and the total score on the questionnaire regarding dietary habits according to the RDA rates of total energy and calcium (Ca) were investigated. Then, the comparisons of intake of food groups, intake of nutrients and the total score on the questionnaire regarding dietary habits according to potassium/energy (K/E) ratio and phosphorus/calcium (P/Ca) ratio were determined. Last, differences between comparisons with the nutrient rates of RDA and comparisons with K/E ratio and P/Ca ratio were investigated. The following results were obtained: 1. Even in the group with RDA rates of total energy or Ca of > or = 90% and < or = 110% the RDA rates of some other nutrients were out-side the appropriate range. 2. In the group with high K/E ratios, as compared to the group with low ratios, the intake of potatoes, pulses, fruits, green/yellow vegetables, other vegetables, soy sauce, other beverages, fish/shellfish, and milk products showed high values, while cereals and fats/oils showed low values. For this reason, in the former group as compared to the latter, the intake and RDA total energy rate showed low values whereas the intake and RDA rates of nutrients such as Ca, Fe, and vitamin A were low. 3. In the group with high P/Ca ratios, as compared to the group with low ratios, the intake of beer and meats showed high values while that of pulses, green/yellow vegetables, and milk products showed low values. For this reason, in the former group as compared to the other groups, despite the fact that the intake and RDA total energy rate tended to be higher, the intake of nutrients such as Ca, P, K, and vitamin A showed lower values. 4. The RDA rates of all of the nutrients of group with a high K/E ratio and the group with a low P/Ca ratio generally showed largely appropriate values. 5. These results suggest that indices reflecting the balance of minerals such as the K/E and P/Ca ratios more objectively reflect the quality of nutrition than comparisons based on the RDA rates of total energy and specific-nutrient.