Hemophilus influenzae type B susceptibility to 17 antibiotics

One hundred and one strains of Hemophilus influenzae type b isolated at the Children's Hospital Medical Center from blood or CSF and 18 strains known to be resistant to ampicillin of which 17 were supplied to us by others were tested for their sensitivity to 17 antibiotics. Two groups were defined according to their sensitivity to ampicillin. When 10-3 bacteria were applied, 18 strains isolated from patients with ampicillin treatment failures had a median minimum inhibitory concentrations of 3.1 mug/ml. At 10-6 bacteria the median MIC for the resistant strains increased 512-fold, whereas the sensitive strains increased two-fold. The most active antibiotics against sensitive and resistant strains were rifampin, chloramphenicol, gentamicin, rosamycin, and erythromycin with MICs ranging from 0.2-0.8 mug/ml at 10-3 bacteria and from 0.2-1.6 mug/ml at 10-6.

Tuberculous meningitis in childhood

The 43 cases of tuberculous meningitis treated at the Royal Children's Hospital, Melbourne, over the 15-year period from January, 1954, to December, 1969, are reviewed in detail. With "triple drug" antituberculosis therapy, 19 patients made a full recovery and seven died. Of the other 17, 11 had major permanent sequelae. There was a strong correlation between the patient's state of consciousness at the time antituberculosis therapy was commenced and the ultimate result. Suggestions are made on how the mortality and morbidity can be reduced.

Triploidy and haploid-triploid mosaicism among chick embryos (Gallus domesticus)

Homomorphic, chromosomally abnormal roosters were mated to normal hens. The 23 hens produced 67 embryos, including two triploids and a haploid-triploid mosaic at about 26 hours of incubation. Both of the triploid embryos were conceived within a 5-day period. The presence of a single genome of paternal origin with marker chromosomes in each triploid led to the conclusion that these embryos were derived from diploid, ZW-type ova fertilized by haploid, Z-type spermatozoa. The inheritance pattern of the mosaic embryo was clearly due to a spermatozoal origin for the haploid cell line; and one genome of the three in the triploid cell line was paternal. The sec chromosomes were Z/ZZZ, with one Z of each cell line being a translocation product of paternal derivation.

Barbiturate protection from cerebral infarction in primates

Baboons were anesthetized with halothane or pentobarbital prior to middle cerebral artery (MCA) occlusion to test the protective effect of barbiturates against stroke in primates. Significantly less infarction was found in animals that received 90 mg per kilogram pentobarbital or more than occurred in control animals. Because of cardiovascular and ventilatory complications at high doses of barbiturate, however, therapeutic trials to suppress stroke in the human must await further identification of an effective regimen which includes a safe barbiturate dose.

Lipid peroxidation by human blood phagocytes

Cell suspensions enriched in human blood monocytes, obtained from normal peripheral blood by sedimentation on sodium diatrizoate-Ficoll gradients or from the blood of patients with neutropenia and monocytosis, accumulated malonyldialdehyde, a labile catabolite of lipid peroxidation, during incubations with polystyrene beads or heat-killed Staphylococcus epidermidis. Mixed blood leukocytes principally composed of granulocytes or granulocytes purified by density gradient sedimentation did not accumulate malonyldialdehyde during incubations with these particles, but did when ingesting particles containing linolenate. The phospholipid fatty acid composition of monocyte-enriched and purified granulocyte preparations from the same donors were compared. The molar fraction of arachidonate (20:4) in phospholipids from monocyte-rich preparations was 62% greater than that of purified granulocytes. The findings indicate that human monocytes, possibly because of a greater content of polyunsaturated fatty acids in their membranes, peroxidize a greater quantity of endogenous lipids than granulocytes during endocytosis. Normal human granulocytes have the capacity to peroxidize ingested lipids. However, mixed leukocytes from two patients with chronic granulomatous disease produced little malonyldialdehyde when engulfing linolenate-containing particles. Therefore the capacity to peroxidize lipid is related to cellular oxygen metabolism, a function in which chronic granulomatous disease granulocytes are dificient. Malonyldialdehyde chemically prepared by hydrolysis of tetramethoxypropane, by extraction from peroxidized linolenic acid, or purified from extracts of phagocytizing rabbit alveolar macrophages had bactericidal activity against Escherichia coli and S. epidermidis. Therefore, toxic catabolites of lipid hydroperoxides may potentiate the bactericidal activity of hydrogen peroxide in mononuclear phagocytes.

Modification of antibiotic resistance in gram-negative bacteria by penicillinase inhibition

The correlation coefficient between the rapid enzymatic and the overnight microbiological assays for 211 urine and serum specimens was 0.96. The 95% confidence limits yielded a correlation coefficient between 0.92 and 0.98. Both methods tended to underestimate the amount of a gentamicin added to urine. When only serum samples were considered, the predicted value obtained from the linear regression analysis of either method was within 0.57 μg/ml 99% of the time. This high degree of positive correlation will permit safe rapid adjustment of individualized patient gentamicin dosages.

Brain polymorphonuclear leukocyte quantitation by peroxidase assay

Rat brain polymorphonuclear infiltration was quantitated by spectrophotometric assay of myeloperoxidase activity. Peroxidase was assayed by following the oxidation of o-dianisidine in the presence of a hydrogen peroxide generating system (glucose-glucose oxidase). Enzyme activity was proportional to the number of polymorphonuclear leukocytes present at densities between 10(5) and 10(6) cells. Brain tissue did not have detectable peroxidase activity and polymorphonuclear leukocytes added to brain homogenates were quantitatively estimated. In infant rats with Haemophilus influenzae meningitis, the correlation between the number of polymorphonuclear leukocytes found in brain by peroxidase activity measurement and independent histological grading was not precise, but there was an exact correlation in predicting presence or absence of polymorphonuclear leukocytes. Myeloperoxidase activity appears to afford a rapid convenient tool for quantitative determination of tissue polymorphonuclear leukocyte content.

Barbiturate protection in acute focal cerebral ischemia

We have found that anesthetic technique modifies the neurological and pathological sequelae of unilateral middle cerebral artery and internal carotid artery occlusion in dogs. Occlusion was performed in seven groups of six dogs during each of the following anesthetic regimens: light (0.8%) halothane, "awake," deep (1.9%) halothane, deep halothane with mean arterial pressure reduced to 55 torr, pentobarbital (56 mg per kilogram), light halothane plus 40 mg per kilogram thiopental begun just before cerebral artery occlusion, and light halothane plus 40 mg per kilogram thiopental begun 15 minutes after occlusion. Body temperature, arterial P co co 2 P o o 2 pH, and blood pressure (except as noted above) were maintained normal. Neurological examinations were performed daily. On the seventh day the dogs were killed and their brains removed for pathological study. Hemiparesis occurred in five of six dogs under light halothane and five of six awake dogs; a mean of 10.8% and 9.6%, respectively, of their right hemispheres were infarcted. In the deep halothane groups, all of the normotensive and five of the six hypotensive dogs became severely hemiplegic; mean infarction size was 28.2% and 34.1%, respectively. Only one of the 18 dogs who received a barbiturate sustained a neurological deficit -- a transient unilateral weakness. Means of 1.4%, 2.7%, and 0.1% of the right hemisphere were infarcted in the barbiturate animals. The protective action of barbiturates in canine acute focal cerebral ischemia suggests that they should be considered for anesthesia in surgery requiring cerebral vessel occlusion and perhaps even for treatment of acute stroke.

Production of Haemophilus influenzae b meningitis in infant rats by intraperitoneal inoculation

Sprague-Dawley rats have a marked age-related susceptibility to Haemophilus influenzae type b that does not correlate with serum bactericidal activity. Eighty percent of 5-day-old animals that survive to 48 h after an intraperitoneal inoculation of a mean lethal dose of bacteria have histologically documented meningitis. Animals surviving the inoculations as infants manifest cerebral dysfunction as adults. This model should facilitate experimental study of bacterial meningitis.

Riboflavin and mouse hepatic cell structure and function. II. Division of mitochondria during recovery from simple deficiency

Mice which had been on a riboflavin-free diet for 6-8 wk were given daily intraperitoneal injections of riboflavin. The hepatic mitochondria, which in the deficient animals were greatly enlarged, were restored to normal dimensions within 3 days. Normalization of the mitochondrial population was brought about by division of the giant organelles. Dividing mitochondria were characterized by a membranous partition separating the inner compartment into two distinct chambers. Such organelles showed varying degrees of pinching at the level of the partition. The most common site of partition formation was at the base of a small mitochondrial bud. During the 1st day of recovery, dividing mitochondria were so common that they could be easily found in mitochondrial pellets. Injection of riboflavin into normally nourished mice also produced an apparent increase in the frequency of dividing mitochondria in the liver cells.

Induction of brain D(--)-beta-hydroxybytrate dehydrogenase activity by fasting

D(m)-beta-hydroxybutyrate dehydrogenase activity is very low in normal adult rat brain; but during fasting it increases severalfold in parallel with the ketosis. The increase may represent part of a mechanism by which the brain adapts to changing patterns of substrate supply during starvation.

Optimizing the operating parameters of infrared spectrometers

In order to achieve best results with modern ir spectrometers, users must take considerable care to optimize the setting of the slit program, response time, gain, and scan time. In this paper, explicit recommendations are given for carrying out such adjustments in a logical and self-consistent manner. First, a set of conditions is derived for the recording of general purpose spectra. From this starting point, settings may be modified to record spectra under the following special conditions: low noise level, limited optical energy, high resolution, and rapid scanning. Proper use of the scan speed suppression control is discussed.