Natural killer cells are not required for interferon-mediated prophylaxis against vaccinia or murine cytomegalovirus infections

Natural killer (NK) cell-depleted or control mice were treated prophylactically with polyinosinic: polycytidylic acid (polyI: polyC) or purified beta interferon (IFN) and then infected with either vaccinia virus or murine cytomegalovirus. NK cell depletion alone enhanced virus titres in the spleen and peritoneal cavity. However, poly I: polyC and IFN inhibited virus replication equally well in control and NK cell-depleted mice. This suggests that prophylactic IFN treatment mediates antiviral effects independently of NK cells.

Effect of a carbohydrate-restricted, calorie-reduced diet on the growth of young rats and on serum growth hormone, somatomedins, total thyroxine and triiodothyronine, free T4 index, and total corticosterone

We have studied the effect of a carbohydrate-restricted, calorie-reduced diet on the growth of young rats and on serum levels of GH, somatomedins [insulin-like growth factors (IGFs) I and II], total T4 and T3, free T4 index, and total corticosterone. Experimental animals consumed the same quantities of protein and fat as controls, but only 50.3% as much carbohydrate and 76% as many calories. While the experimental group grew at 69.4% of the control rate, their mean (+/- SEM) GH level (175.7 +/- 36.9 ng/mL) was not significantly different from that in the control group (180 +/- 30 ng/mL). In contrast, serum total IGF and IGF-I, while not correlated with serum GH levels, were significantly correlated in all animals with body weight (r = .87 and r = .82, respectively, P less than .01) and tail length (r = .61 and r = .62, respectively, P less than .01). The somatomedin levels of the carbohydrate-restricted rats were significantly lower than those of their age-matched, but not weight-matched, controls by the eighth day of study. Serum T4, T3, and free T4 index were not significantly different in these two groups, while total corticosterone in the experimental group (245 +/- 73 ng/mL) was slightly lower than in controls (292 +/- 80 ng/mL, P less than .05). These data indicate that by restricting carbohydrate intake we have compromised the anabolic use of dietary protein by growing rats, resulting in a retardation of growth and a reduction in serum total IGF and IGF-I levels.

Purification and properties of Escherichia coli 4'-phosphopantothenoylcysteine decarboxylase: presence of covalently bound pyruvate

4'-Phosphopantothenoylcysteine decarboxylase was purified 900-fold from Escherichia coli B with an overall yield of 6%. The enzyme migrates as a single band with a molecular weight of 35,000 +/- 3000 in 10% polyacrylamide gel electrophoresis under denaturing conditions. The native enzyme has an apparent molecular weight of 146,000 +/- 9000 as determined by a gel exclusion column. At pH 7.6 and 25 degrees C, Km = 0.9 mM and Vmax = 600 nmol/(min X mg of protein). The pH optimum for Vmax is between 7.5 and 7.7. Hydroxylamine, phenylhydrazine, potassium cyanide, and sodium borohydride as well as pyridoxal phosphate and pyridoxal inactivated the enzyme. The enzyme contains covalently bound pyruvate as suggested by the isolation of [3H]lactate and pyruvate from [3H]NaBH4-reduced enzyme and native enzyme, respectively. One mole of [3H]lactate was isolated per 39,000 g of [3H]NaBH4-reduced and completely inactivated enzyme, and 1 mol of pyruvate was isolated per 31,000 +/- 4000 g of native enzyme. Mild base treatment released lactate and pyruvate from the reduced and the native enzymes, respectively, suggesting the pyruvate is attached to the enzyme by an ester bond. These findings are in accord with similar results obtained with the horse liver enzyme (R. Scandurra, personal communication). The presence of covalently bound pyruvate in the bacterial and mammalian enzymes suggests that pyruvate plays a major role in the mechanism of action.

Changes in the health situation among the rural population and the challenges to the preventive services in China

China has a population of one billion, of which 80% live in rural areas. Faced with the changing situation in rural health care work subsequent to the economic structural reform in the vast rural areas and their challenges to the prevention services, appropriate measures in Chinese rural health care work were taken. All levels of leaders of health care and other departments were instructed to adhere to the policy of “prevention first”, to expand the functions and tasks of prevention, to reform the current health organisational structure, to strengthen the three-level health care network and to collect funds from various sources to support health care work and the prevention of disease.

Enzymatic transformation of PGH2 to PGF2 alpha catalyzed by glutathione S-transferases

Glutathione S-transferases (GSTs) purified from both rat liver cytosol and microsomes catalyzed the direct reduction of PGH2 to PGF2 alpha. As much as 40% of the substrate was transformed into a prostanoid whose Rf value corresponded to that of PGF2 alpha. The identification of the reaction product as PGF2 alpha was confirmed by TLC and reverse-phase HPLC as well as by mass spectral analysis. In the absence of GSTs, PGH2 was found to be primarily converted to PGE2 and PGD2. Also, PGF2 alpha formation was completely abolished by decylglutathione, a potent inhibitor of both peroxidase and transferase activity associated with GSTs. These results indicate that the direct reduction of endoperoxide moiety of PGH2 to form PGF2 alpha is an enzymatic process. Interestingly, selenium-dependent glutathione peroxidase (Se-GSH-Px) showed very little PGF2 alpha formation from PGH2. However, this enzyme was very active in the reduction of PGG2 to PGH2. In contrast, GSTs were very poor in the conversion of PGG2 to PGH2. Therefore, it is possible that the relative tissue distribution of Se-GSH-Px and GSTs might play an important role in the tissue specific synthesis of PGF2 alpha.

Induction of alloreactive cytotoxic T cells by acute virus infection of mice

Alloreactive cytotoxic T lymphocytes (CTL) distinct from virus-specific CTL and activated natural killer (NK) cells were generated during acute lymphocytic choriomeningitis virus (LCMV) infection of C57BL/6J mice. The alloreactive CTL shared similar antigenic markers (Thy-1.2+, Lyt-2.2+, and asialo GM1-) with the virus-specific CTL that appeared at the same time 7 days postinfection, but had different target specificities. These alloreactive CTL lysed allogeneic but not syngeneic or xenogeneic targets. These were distinct from activated NK cells, which lysed all target cell types, peaked 3 days postinfection, and had a phenotype of asialo GM1+, Thy-1 +/-, Lyt-2.2-. Cold target competition studies indicated that there were several subsets of alloreactive T cells with distinct specificities, and that these alloreactive T cells were not subsets of the virus-specific T cells. Similar types of alloreactive CTL were induced at much lower levels in C3H/St mice. This may indicate that the generation of this "aberrant" T cell activity is under genetic control. Hence, the LCMV infection of C57BL/6J mice induces several cytotoxic effector populations including alloreactive CTL, activated NK cells, and virus-specific CTL. Virus infections therefore have the ability not only to polyclonally stimulate B cells, as previously described, but also to stimulate CTL.

The isolation and partial characterization of a highly pathogenic herpesvirus from the harbor seal (Phoca vitulina)

This report describes the first isolation and partial characterization of a herpesvirus from the harbor seal (Phoca vitulina). The virus was isolated during a disease outbreak in a group of young seals nursed in a seal orphanage in The Netherlands. Almost half of the seals died with symptoms of acute pneumonia and focal hepatitis and the virus was isolated of organs of most of the dead animals. Seven out of ten seals of which paired serum samples were obtained showed seroconversion in a virus neutralization test during this outbreak. The virus was tentatively characterized as a herpesvirus (seal herpesvirus: SeHV or phocid herpesvirus 1) on the basis of its characteristic morphology in electron microscopy, buoyant density in sucrose, sensitivity to ether and heat treatment and its antigenic relationship with other probable members of the Alphaherpesvirinae subfamily. The virus caused cytopathic changes within 24 hours after inoculation in seal kidney cells, consisting of a focal rounding of cells and syncytium formation. No cytopathic changes were observed in the cells of nine other mammalian species tested.

Escherichia coli pyruvate dehydrogenase complex: particle masses of the complex and component enzymes measured by scanning transmission electron microscopy

Particle masses of the Escherichia coli pyruvate dehydrogenase (PDH) complex and its component enzymes have been measured by scanning transmission electron microscopy (STEM). The particle mass of PDH complex measured by STEM is 5.28 X 10(6) with a standard deviation of 0.40 X 10(6). The masses of the component enzymes together with their standard deviations are (2.06 +/- 0.26) X 10(5) for the dimeric pyruvate dehydrogenase (E1), (1.15 +/- 0.17) X 10(5) for dimeric dihydrolipoyl dehydrogenase (E3), and (2.20 +/- 0.17) X 10(6) for dihydrolipoyl transacetylase (E2), the 24-subunit core enzyme. The latter value corresponds to a subunit molecular weight of (9.17 +/- 0.71) X 10(4) for E2. The subunit molecular weight measured by polyacrylamide gel electrophoresis in sodium dodecyl sulfate is 8.6 X 10(4). STEM measurements on PDH complex incubated with excess E3 or E1 failed to detect any additional binding of E3 but showed that the complex would bind additional E1 under forcing conditions (high concentrations with glutaraldehyde). The additional E1 subunits were bound too weakly to represent binding sites in an isolated or isolable complex. The mass measurements by STEM are consistent with the subunit composition 24:24:12 when interpreted in the light of the flavin content of the complex and assuming 24 subunits in the core enzyme (E2).

T cell-dependent and -independent stimulation of hamster spleen NK-like cells with concanavalin A

This study was designed to examine the inducibility and lineage of nonspecifically cytotoxic effector cells in the hamster spleen. Employing a known T cell mitogen, concanavalin A (ConA), and a monoclonal antibody against a recently identified hamster T cell marker (Thy 1.2 homologue), we examined the effector cells induced in spleen by ConA and the role of T cells in regulating this response. Cytotoxicity was measured against uninfected baby hamster kidney cells, cells infected with herpes simplex virus, or a mouse target, SV3T3, in a 16-hr 51Cr release assay. Pretreatment of spleen cells with ConA (2.5-10 micrograms ConA/ml) markedly augmented killing of all targets. Although ConA pretreatment of effector cells enhanced cytotoxicity, pretreatment of targets did not, indicating that ConA is acting at the effector cell level. Supernatants from ConA-stimulated spleen cells also augmented spleen lymphocyte cytotoxicity, suggesting that the ConA effect is mediated by lymphokines (LK). Depletion of Thy 1.2-positive cells from the spleen cells failed to influence augmentation of cytotoxicity by either ConA or ConA-induced LK, indicating that the precursor cells are not T cells. However, depletion of Thy 1.2-positive cells completely eliminated the production of LK in response to ConA, indicating that the factors in LK that augment cytotoxicity are strictly T cell dependent. Whether nonspecific cytotoxic cells induced by ConA in the absence of T cells and by the T cell LK are the same population is not known. None of the cytotoxicity induced from intact or T cell-depleted spleen cells by either ConA or LK expressed the Thy 1.2 homologue. These results suggest that nonspecific cytotoxic lymphocytes of non-T cell lineage in the hamster are regulated via both T cell-dependent and T cell-independent mechanisms.

The incidence of hypercalcemia in squamous cell carcinoma of the head and neck

Hypercalcemia is a well-recognized phenomenon in squamous cell carcinoma of the head and neck, but the incidence of hypercalcemia in this group of patients is not clear. We have reviewed the records of 166 patients with squamous cell carcinoma of the head and neck presented at the Boston VA Medical Center over a 2-year period (October 1981 to September 1983). Hypercalcemia (greater than 11 mg/dl), for which a benign etiology could not be identified, occurred in the clinical course of seven patients (4.2%). Of the hypercalcemic patients, 5/7 (71.4%) had advanced stage IV disease and serum calcium levels ranging from 11.2 to 15 mg/dl at presentation. The incidence of hypercalcemia in this stage IV group was 5/78 (6.4%). On the basis of concomitant serum alkaline phosphatase, x-ray films, and radionuclide bone scans in these patients, bone metastases or a humoral factor were felt to be the etiologic agent. Six of the seven patients died within 77 days of the onset of the hypercalcemia despite vigorous antihypercalcemic and chemotherapeutic measures, and the remaining patient is under chemotherapy at present. We conclude that hypercalcemia is a late manifestation of advanced squamous cell carcinoma of the head and neck and is an ominous prognostic sign. Hypercalcemia without bone metastases is presumably due to the production of ectopic parathormone (PTH)-like substances from the tumor. To control this hypercalcemia, the underlying tumor must be treated vigorously in conjunction with symptomatic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of undecagold cluster molecules as biochemical labeling reagents. 2. Bromoacetyl and maleimido undecagold clusters

Derivatives of heptakis[4,4',4"-phosphinidynetris(benzenemethanamine) ]undecagold, 1, molecular formula Au11(CN)3[P(C6H4CH2NH3)]7, are described. These include undecagold complexes with a single free primary amino group, a single bromoacetyl group, and a single maleimido group per molecule. Hydrolysis of mono(N-phthalyl)icosa(N-acetyl)-1 at pH 3.2 and 46 degrees C under anaerobic conditions and in the presence of NaBH3CN produces icosa(N-acetyl)-1. Partial acylation of 1 with 1.3 equiv of 2,3-dimethylmaleic anhydride followed by complete acetylation with acetic anhydride produces a mixture consisting largely of mono- and bis(dimethylmaleyl)peracetyl-1. Hydrolysis of 2,3-dimethylmaleimides at pH 3.2 for 1 at 25 degrees C produces a mixture of icosa(N-acetyl)-1, with a single free amino group, and nondea(N-acetyl)-1. This mixture can be quantitatively separated by cation-exchange chromatography at pH 7, giving homogeneous icosa(N-acetyl)-1 in an overall yield of 55%. Icosa(N-acetyl)-1 serves as the starting material for the synthesis of the alkylating derivatives mono(N-bromoacetyl)icosa(N-acetyl)-1 and mono[N-(p-maleimidobenzoyl)]icosa(N-acetyl)-1. These derivatives can be used for alkylating proteins in preparation for electron microscopy.

Synthesis of undecagold cluster molecules as biochemical labeling reagents. 3. Dimeric cluster with a single reactive amino group

The synthesis and characterization of a dimeric derivative of the undecagold cluster complex Au11(CN)3[P-(C6H4CH2NH2)3]7, 1, are described. The dimer, 2, consists of cross-linked molecules of 1 in which 41 of the 42 amino groups are acylated, leaving a single free amino group per dimer. This amino group is reactive and can be used to prepare derivatives of 2 for use in labeling biological macromolecules in preparation for electron microscopic analysis. Limited acylation of 1 by 1.3 equiv of citraconic anhydride in aqueous solution, followed by extensive acylation with acetic anhydride at pH 7-7.5, leads to a mixture of monomeric and dimeric products. Hydrolytic removal of N-citraconyl groups at pH 3.2 unmasks a few amino groups. Cation-exchange chromatography at pH 7 separates the products into three main groups, species containing one, two, or three free amino groups, in overall yields of 33%, 28%, and 15%, respectively. The monoamino species consist mainly of 2 and a monomeric product, which are separated by gel exclusion chromatography. 2 migrates as a dimer upon polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and it contains a single free amino group, detectable by its ion-exchange behavior as a monocation at pH 7 and by its reactivity with [14C]phthalic anhydride.

Nonspecific cytotoxicity of vaccinia-induced peritoneal exudates in hamsters is mediated by Thy-1.2 homologue-positive cells distinct from NK cells and macrophages

Vaccinia virus-induced peritoneal exudate cells (PEC) in the hamster were characterized with regard to cell type(s), target specificity, and expression of the T cell antigen, Thy 1.2 homologue. Hamsters were immunized intraperitoneally with vaccinia virus and cytotoxicity was measured against 51Cr-labeled targets in a 16-hr assay. PEC collected 4 days after immunization were cytotoxic for both baby hamster kidney cells (BHK) and herpes virus-infected BHK (BHKHSV). Both the nonadherent (lymphocyte) and adherent macrophage (MP) fractions of PEC were cytotoxic. Treatment of cells with a monoclonal anti-murine Thy 1.2 antibody (alpha-Thy 1.2) known to detect a Thy 1.2 homologue on hamster T cells, removed all of the cytotoxicity in both PEC fractions, whereas, cytotoxic spleen cells from the same animals were resistant to antibody treatment. Similarly, the cytotoxic cells in PEC induced by bacillus Calmette-Guérin were exclusively of the Thy 1.2 homologue-positive phenotype. Target specificities of Thy 1.2+ PEC and Thy 1.2- spleen cells were similar as evidenced by comparable activity against hamster BHK and BHKHSV targets and murine SV3T3 and YAC-1 targets. Previous studies have attributed the cytotoxicity of the adherent PEC to MP. However, as determined by immunofluorescence and morphological studies, treatments that enriched for MP decreased cytotoxic activity, whereas, procedures that enriched for lymphocytes enhanced cytotoxic activity suggesting that all cytotoxicity in PEC is mediated by a non-specific Thy 1.2 homologue positive lymphocyte (Thy 1.2+ CL). Thus our data support the conclusion that intraperitoneal inoculation of hamsters with vaccinia induces two distinctly compartmentalized phenotypes with similar cytotoxic characteristics--the Thy 1.2+ CL and the Thy 1.2 homologue-negative natural killer cell (NK) or NK-like cell in the peritoneum and in the spleen, respectively.