In vitro activity of ceftriaxone and other cephalosporins against 602 clinical isolates of staphylococci from geographically diverse medical centers

The in vitro activity of ceftriaxone and six additional antimicrobial agents (ceftizoxime, cefoperazone, cefuroxime, fleroxacin, ciprofloxacin, and trimethoprim/sulfamethoxazole) was assessed or 602 recent clinical isolates of staphylococci from six geographically distinct medical centers in North America. All seven antimicrobial agents were active (90–100% of strains susceptible) against oxacillin-susceptible (OS) strains of Staphylococcus aureus (OSSA) and coagulase-negative staphylococci (OSCNS) but had limited activity against oxacillin resistant (OR) staphylococci. Our assessment of the in vitro antistaphylococcal activity of ceftriaxone against contemporary isolates of Staphylococcus aureus and coagulase-negative staphylococci indicates that the activity versus OS staphylococci has not changed over the past decade despite widespread use of the drug. It appears that these agents will continue to be useful for empiric therapy in those centers in which OR strains are uncommon.Corresponding author.     

Assessment of renal artery stenosis by phase-contrast magnetic resonance angiography

Three-dimensional (3D) phase-contrast magnetic resonance angiography (MRA) and velocity-encoded cine magnetic resonance (VEC-MR) imaging were performed in 23 subjects to assess the severity of renal artery stenosis. MRA was used for detection of stenosis, demonstrating a sensitivity of 100% and a specificity of 80%; the severity of stenosis was overestimated in 33%. VEC-MR was used to quantify the renal flow oattern and was successful in 11 subjects. Mean blood flow of normal renal arteries (420 +- 107 ml/min) was significantly higher (P < 0.01) than mean blood flow of stenotic arteries (131 +- 46ml/min). The flow profile displayed both systolic and diastolic peaks in 75% of the normal arteries, while the flow in stenotic arteries showed only a single systolic peak in all cases. The systolic peak in stenotic arteries occurred significantly later (32 +- 3% of the period of one cardiac cycle) than in normal subjects (21 +- 7%) (P < 0.05). Phase-contrast MR is likely to gain considerable importance in the noninvasive aetection and quantification of renal artery stenosis. Correspondence to: C. S. Richter     

An Immunotoxicological Evaluation of 4, 4'-Thiobis-(6-t-butyl-m-cresol) in Female B6C3F1 Mice: 1. Body and Organ Weights, Hematology, Serum Chemistries, Bone Marrow Cellularity, and Hepatic Microsomal Parameters

An Immunotoxicological Evaluation of 4,4'-Thiobis-(6-t-butyl-m77-cresol)in Female B6C3F1 Mice. 1. Body and Organ Weights, Hematology,Serum Chemistries, Bone Marrow Cellularity, and Hepatic MicrosomalParameters. MUNSON, A. E., WHITE, K. L., JR., BARNES, D. W.,MUS-GROVE, D. L., LYSY, H. H., AND HOLSAPPLE, M. P. (1988).Fundam. Appl. Toxicol. 10, 691–700. Adult female B6C3F1mice were gavaged with 4,4'-thiobis-(6-t-butyl-m-cresol) (TBBC)in corn oil at doses of 10, 100, or 200 mg/kg daily for 14 consecutivedays. There was no overt toxicity, as manifested by grosslyobservable behavioral changes, decreased growth rate over theexposure period, or mortality. There were also no marked effectson serum chemistries or hematology, with the exception of asignificant increase (41%) in the number of leukocytes at thehighest dose. Absolute differential counts indicated that significantincreases occurred in the number of lymphocytes (31%) and neutrophils(177%). Studies with bone marrow indicated a significant 30%increase in the number of cells/femur from animals treated withthe highest dose of TBBC. The number of macrophage progenitors(CFU-M)/femur was significantly increased by 28%, while thenumber of granulocyte-monocyte progenitors (CFU-GM)/femur wasnonsig-nificantly increased by 20% in the high dose animals.The weight of both the spleen and liver was increased in a dose-relatedfashion, although the histopathology of the spleen of TBBC-treatedmice was not different from control. The livers of mice receivingthe high dose showed mild focal hydropic degeneration, mildhepatitis, and a slight increase in the number of Kupffer cells.No other organs were affected. Liver microsomal protein andcytochrome P-450 levels were increased in a dose-related fashion.Enzyme activities of aminopyrine demethylase and aniline hydroxylase,but not arylhydrocarbon hydroxylase, were also increased ina dose-related fashion.     

Immunotoxicity of the Semiconductor Gallium Arsenide in Female B6C3F1 Mice

The effects of gallium arsenide (GaAs) exposure on immunocompetenceof B6C3F1 female mice were investigated. GaAs was administeredas a single intratracheal instillation at doses of 50, 100,and 200 mg/kg. Fourteen days after exposure, various cellularand humoral immune parameters were assessed. GaAs exposure increasedspleen cellularity in a dose-dependent manner. However, thepercentages of Thy 1.2 positive and 1g positive cells were decreasedand that of F4/80 positive cells was increased dose dependency.The IgM and IgG antibody-forming cell response of the spleento the T-dependent antigen sheep erythrocytes was reduced by66 and 48%, respectively, at 200 mg/kg. Levels of the serumcomplement protein, C3, were increased by as much as 16% withno significant change in CH50 levels. The mitogenic responseof splenic T cells to Con A and PHA was unaffected by GaAs,but that of B cells to LPS was increased by 52%. The delayedhypersensitivity response to keyhole limpet hemocyanin and mixedlymphocyte response were significantly reduced in a dose-dependentmanner by GaAs exposure. Natural killer cell activity againstthe YAC-1 mouse lymphoma was enhanced in treated mice. Analysisof peritoneal exudate cells (PEC) revealed a dose-dependentdecrease in number and a shift in the composition of PECs. Thepercentage of PEC monocytes increased from 53% of the populationto 81%, while the lymphocytes decreased from 46 to 20%. Theadherent PEC population demonstrated decreased phagocytosisof covaspheres and increased phagocytosis of chicken erythrocytes(CRBC). GaAs exposure had no effect on host resistance to Plasmodiumyoelii or Streptococcus pneumoniae, but dose dependency increasedresistance of the mouse to Listeria monocytogenes Treated micedemonstrated a significantly decreased resistance to the B16F10melanoma with a sevenfold increase in tumor burden at 200 mg/kg.GaAs affects both humoral and cellular immune parameters inmice and impairs the ability of the immune system to protectagainst B16F10 tumor challenge.     

Progress in Rhesus Histocompatibility Typing Resulting from the Second International Nonhuman Primate Histocompatibility Workshop (1973)

The Second International Nonhuman Primate Histocompatibility Workshop permitted comparison of rhesus monkey alloantisera developd in various laboratories on a single common panel of related and unrelated monkeys. Analysis of the data permits the conclusion that at least nine specificities are recognized by more than one laboratory, including six at the first locus and three at the second locus.     

The Gm-Pi linkage heterogeneity in view of Pi M subtypes

In this study linkage between the loci for Gm (γ-type heavy-chain immunoglobulin markers) and Pi (α₁-antitrypsin/α₁-protease inhibitor) has been shown in families segregating for the Pi M subtypes (Ml, M2, M3 and Msal) as identified by separator isoelectric focusing. The estimate for the Gm-Pi (M-type) recombination is 0-29 (95% limits 0-24-O37) at a peak lod score of 4-31 and with no sex difference. This value is not significantly different from updated recombination frequency estimates for Gm-Pi in Pi MS (0-26) and Pi MZ, SZ and FZ families (0 21). The overall Gm-Pi recombination fraction estimate of 0 26 (95 % limits O23-0-30) at a peak lod score of 20-75 must now be considered as solid. There is a significant heterogeneity within the male Pi MZ families in that the new Finnish families show a higher recombination between Gm and Pi. There is also a possible segregation distortion (Z:M = 23:8). The heterogeneity is discussed in terms of haplotypes, the behaviour of which could be determined by linked genes or chromosomal rearrangements. The possibility that the α₁-antitrypsin level influences recombination frequency has not been ruled out, but cannot explain the heterogeneity within Pi MZ families.     

Effect of chronic vincristine treatment on mechanical withdrawal response and pre-pulse inhibition in the rat

Chemotherapeutic agents are associated with a number of serious side-effects. In addition to the development of peripheral neuropathy, patients often complain of additional symptoms related to attentional mechanisms. Although a great deal of interest is directed towards understanding the mechanisms underlying the development of peripheral neuropathy, there is a paucity of research that has examined the extent of impairment of attention in animals receiving chemotherapeutic agents. Therefore, the purpose of this experiment was to examine attentional mechanisms using the method of pre-pulse inhibition in animals that were chronically treated with vincristine. Although vincristine treated animals developed signs of peripheral neuropathy, there was no associated alteration of pre-pulse inhibition relative to vehicle treated animals. These results highlight the importance of continuing to develop methodology to model symptom burden in patients receiving chemotherapy.     

Ramification of the portal vein at the porta hepatis in humans

The ramification of the portal vein at the porta hepatis was studied by anatomic dissection performed in 32 formalin fixed human livers. In all the specimens there were branches which ran towards the caudate lobe, arising from the portal vein and either from the left or the right portal branches. Tri-and quadrifurcation of the portal vein was observed. In 5 cases (16%) there were branches arising from left portal branch or portal vein and directed anteriorly to the quadrate lobe or to the region of the gall-bladder sulcus. These branches ranged from 1.0 to 6.0 mm in diameter. The portal caudate branches were divided into 3 groups.Group 1: Branches to the papillary process; 1 or 2 branches in 26 cases (82%), 3 or 5 branches in 3 cases (9%) and no branches in 3 cases (9%);