Morphologic and biomechanical study of avascular necrosis of the femoral head

Radiologic review and uniaxial compression tests of 1 cm3 cubes of avascular and subjacent portions of 64 femoral heads of 51 patients with idiopathic avascular necrosis of the femoral head were performed to determine the morphologic and biomechanical changes with progression of the disease. Cases were divided into three groups according to the simple radiographic findings: group I (precollapse), group II (collapse), and group III (advanced collapse with secondary degenerative arthritis). Fourteen group I, 36 group II, and 14 group III specimens were identified. In addition to the simple radiographs, 16 magnetic resonance images were reviewed. In group I, there was no significant difference of yield and maximum stress, and modulus of elasticity between avascular and subjacent portions below the reactive rim. In group II, the above parameters showed lower values in the avascular portion than in the subjacent portion (P less than .05). In group III, maximum stress of the avascular portion showed significantly higher value than that of the subjacent region (P less than .05). In groups II and III, a major crack was observed in the subchondral area in 14 specimens and in the deep avascular and reactive junction in 36 specimens. Bone densitometry data suggested higher mineral content indicative of more sclerosis in the deep crack group. These findings might suggest that different biomechanical properties in the subchondral crack group and interface crack group might contribute to varieties in clinical manifestations. Later sclerotic changes and aspherical collapse of the femoral head might play a large role in the development of secondary degenerative arthritis of the hip joint.

Percutaneous absorption-enhancing activity of urea derivatives

The effect of urea and urea derivatives on the percutaneous absorption of salicylic acid and sodium salicylate through the skin of rabbit from petrolatum ointment was investigated. It was found that addition of urea or urea derivatives to the ointment base significantly increased the percutaneous absorption of the drugs in proportion to the concentration of the additive. The percutaneous absorption-enhancing activities of these compounds were that urea derivatives with the more and longer alkyl substituents showed the stronger activities. These activities of urea and urea derivatives were ascribed to the binding of these compounds with the lipids and proteins of the stratum corneum of the skin and the swelling of the tissues, which leads to the reduction of the barrier property of the layer. The preliminary skin irritation test showed that urea and urea derivatives were quite non-irritating to the skin. These results suggest that urea derivatives have a strong possibility to be developed as a percutaneous absorption enhancer.

Intracranial hemorrhage in hypothermic low-birth-weight neonates

We studied periventricular/intraventricular type intracranial hemorrhage (ICH) by cranial ultrasonography in 82 low-birth-weight (LBW) newborn infants with admission hypothermia against the gestational-age-matched 82 normothermic neonates. The incidence of ICH was higher in the hypothermic infants during the 1st week of life (34/82 vs 20/82, P less than 0.02). Although the distribution of individual grades of ICH was not significantly different between the groups, the first ultrasound scan showed higher incidence of major ICH (grades 3 and 4) in the hypothermic infants. Most of the minor ICH (grades 1 and 2) after the first ultrasound appeared in infants who were small for their gestational age. Our data do not support the contention that admission hypothermia can precipitate the development of IVH in LBW infants. However, the detection of admission hypothermia in a LBW neonate should make one suspect the possibility of ICH and regard it as a manifestation of the severity of ICH rather than the cause. Most likely, this close relationship between hypothermia and neonatal ICH originates from perinatal asphyxia and the cumulative adverse effects of asphyxia-related events.

Carbon monoxide dehydrogenase inhibitor in cell extracts of Pseudomonas carboxydovorans

Extracts of heterotrophically grown cells of Pseudomonas carboxydovorans were found to contain an inhibitor of carbon monoxide dehydrogenase (CO-DH). The inhibitor activity was not detected in CO-autotrophically grown cells. The inhibitor was extremely stable to heat treatment based on the extent of inhibition of CO-DH activity. The extent of inhibition was proportional to the amount of cell extract added to the reaction mixture. The inhibition was independent of a prior incubation period of the extracts with CO-DH. The inhibitor was precipitable with ammonium sulfate, phenol, and trichloroacetic acid. It was passed through benzoylated dialysis tubing and Amicon ultrafiltration membrane YM2. Denaturing and nondenturing polyacrylamide gel electrophoresis of CO-DH inactivated by inhibitor revealed that the mobilities of native enzyme and subunits were identical to those of active CO-DH. The inhibitor-treated CO-DH retained its original antigenic sites and exhibited enzyme activity upon activity staining. The CO-DH inhibitor of P. carboxydovorans was also active on CO-DHs from Pseudomonas carboxydohydrogena, Acinetobacter sp. strain JC1, and Pseudomonas carboxydoflava.

Plasmid analysis in pink facultative methylotrophic bacteria using a modified acetone-alkaline hydrolysis method

Routine screening of indigenous and recombinant plasmids in pink facultative methylotrophic bacteria has been difficult, time-consuming, and yields variable results. We report a modified alkaline hydrolysis method for rapid plasmid isolation from these organisms that reproducibly results in good yields of closed circular plasmid DNA which can be readily digested with restriction enzymes. This method greatly facilitates direct screening of indigenous and introduced recombinant plasmids in the methylotrophic host strain. We have confirmed earlier findings that the original NCIB wild-type strain of Methylobacterium sp. strain AM1 (NCIB 9133) contains three cryptic plasmids. However, sizing of these plasmids by comparison to standards and by restriction fragment analysis suggests that they are larger than previously reported. We have designated these plasmids pAM1-1 (65 kb), pAM1-2 (40 kb) and pAM1-3 (33 kb). We have also shown that a rifamycin-resistant strain of Methylobacterium sp. strain AM1 used routinely in our laboratory lacks pAM1-2, although no phenotype has been associated with its loss. Finally, we have shown that another pink facultative methylotroph, Methylobacterium isolate (#YK1), contains three cryptic plasmids of approximately 43, 37 and 22 kb, respectively.

Purification and some properties of carbon monoxide dehydrogenase from Acinetobacter sp. strain JC1 DSM 3803

A brown carbon monoxide dehydrogenase from CO-autotrophically grown cells of Acinetobacter sp. strain JC1, which is unstable outside the cells, was purified 80-fold in seven steps to better than 95% homogeneity, with a yield of 44% in the presence of the stabilizing agents iodoacetamide (1 mM) and ammonium sulfate (100 mM). The final specific activity was 474 mumol of acceptor reduced per min per mg of protein as determined by an assay based on the CO-dependent reduction of thionin. Methyl viologen, NAD(P), flavin mononucleotide, flavin adenine dinucleotide, and ferricyanide were not reduced by the enzyme, but methylene blue, thionin, and dichlorophenolindophenol were reduced. The molecular weight of the native enzyme was determined to be 380,000. Sodium dodecyl sulfate-gel electrophoresis revealed at least three nonidentical subunits of molecular weights 16,000 (alpha), 34,000 (beta), and 85,000 (gamma). The purified enzyme contained particulate hydrogenase-like activity. Selenium did not stimulate carbon monoxide dehydrogenase activity. The isoelectic point of the native enzyme was found to be 5.8; the Km of CO was 150 microM. The enzyme was rapidly inactivated by methanol. One mole of native enzyme was found to contain 2 mol of each of flavin adenine dinucleotide and molybdenum and 8 mol each of nonheme iron and labile sulfide, which indicated that the enzyme was a molybdenum-containing iron-sulfur flavoprotein. The ratio of densities of each subunit after electrophoresis (alpha:beta:gamma = 1:2:6) and the number of each cofactor in the native enzyme suggest a alpha 2 beta 2 gamma 2 structure of the enzyme. The carbon monoxide dehydrogenase of Acinetobacter sp. strain JC1 was found to have no immunological relationship with enzymes of Pseudomonas carboxydohydrogena and Pseudomonas carboxydovorans.

Results of 317 contraction stress tests with controlled nipple stimulation using an electric breast pump

Nipple stimulation is widely used for producing uterine contractions. High rates of hyperstimulation have been reported with various manual methods of stimulation. A study was undertaken in an effort to standardize the mode and amount of stimulation. Three hundred seventeen contraction stress tests were done using an automatic electric breast pump with precise pressure control. This method was successful in achieving adequate contractions in 84.2%. Hyperstimulation of the uterus was encountered in 4.1% of all tests performed. Side effects and complications were minimal.

Intracranial hemorrhage in small-for-gestational-age neonates: comparison with weight-matched appropriate-for-gestational-age infants

In a comparative study of 93 small-for-gestational-age (SGA) infants against 93 weight-matched, appropriate-for-gestational-age (AGA) neonates, the SGA group exhibited a significantly lower incidence of periventricular-intraventricular type intracranial hemorrhage (ICH) at the first ultrasound scan than did the AGA neonates (9/93 vs 21/93; p less than 0.02). This apparent advantage was no longer maintained in later scans of the first week (16/93 vs 27/93; NS), despite the fact that the SGA group were 4 weeks advanced in gestational age and had fewer respiratory problems than the AGA controls. It is prudent, therefore, to follow SGA infants closely for ICH by repeat ultrasound examinations even if the first scan is negative. Evaluation of the subgroup of SGA infants with ICH against the total SGA population revealed lower admission body temperature and Apgar scores, and higher incidence of asphyxia, resuscitation, and mortality. The above observations in SGA infants with ICH and the lack of a similar trend between the AGA infants with ICH and the total AGA population suggest that SGA status, hypothermia, and ICH are interrelated. Hypothermia, therefore, can be used as a convenient marker for the possibility of ICH in low birth weight SGA infants. The authors' data is consistent with the view that hypothermia and ICH are both the consequences of perinatal asphyxia in SGA infants and probably reflect the magnitude of stormy perinatal events.

Serum prolactin levels during contraction stress test done by the breast pump

Maternal serum prolactin (PRL) levels were evaluated in patients having contraction stress tests (CST) by nipple stimulation. Of 79 CSTs, 14 failed and 65 were successful. Poststimulation PRL levels in failed cases were significantly lower than those in gestational age-matched successful cases, despite longer duration of nipple stimulation in the failed cases.

Intracranial hemorrhage in low-birth-weight twins during neonatal period

Since twins have a higher incidence of premature birth, fetal distress, asphyxia and other pre- and intrapartum high-risk factors, it is reasonable to expect that they may be vulnerable to intracranial hemorrhage. Forty-seven pairs of low-birth-weight twins were studied during the newborn period by serial cranial ultrasound. The comparisons of groups, based on birth order, relative size of the neonates, and the mode of delivery, showed no significant differences in the incidence of intracranial hemorrhage between first and second twins, smaller and larger twins, or vaginal and cesarean delivery. However, the comparison based on the presentation of the infant revealed a significantly higher number of intracranial hemorrhages within the first week of life in the breech group than in the cephalic presentation group. The adverse effect of breech presentation on intracranial hemorrhage did not appear to be mediated by the well recognized risk factors such as lower gestational age, lower Apgar scores, and higher incidence of respiratory distress syndrome and assisted ventilation. Since most of the twins with ICH had breech presentation and were delivered by cesarean section, this mode of delivery does not seem to protect the twins with breech presentation from intracranial hemorrhage.

Management of the third stage of labor with nipple stimulation

Nipple stimulation was found to be a safe alternative to oxytocin in the management of the third stage of labor.

Nucleotide sequence of the nifLA operon of Klebsiella oxytoca NG13 and characterization of the gene products

The complete nucleotide sequence of the regulatory operon nifLA of a nitrogen fixer Klebsiella oxytoca NG13 was determined, and the transcriptional start point was assigned by S1 mapping. The nifL protein (a repressor) was coded by an open reading frame of 1,485 bases, corresponding to a protein of 495 amino acids with a calculated molecular weight of 55,242. The open reading frame (1,572 bases) of the nifA protein (an activator), corresponding to a molecular weight of 58,649, was confirmed by in vitro transcription-translation experiments, using the wild type and artificially deleted nifA genes. The initiation codon (ATG) of nifA overlapped the termination codon(TGA) of nifL, sharing the two bases T and G. A conserved DNA contact point [Gln-(X)3-Ala-(X)3-Gly-(X)5-Val] common in many DNA binding proteins was found in the C-terminal region of the nifA sequence. The promoter sequences of nifLA, nifB and nifF in K. oxytoca coincided exactly with those of K. pneumoniae in the consensus regions at -12 and -26, although the overall homology in the promoter regions was 96%. Changes of four amino acids were found between the nifA coding sequences of K. oxytoca and K. pneumoniae.

Subretinal new vessels after krypton laser photocoagulation

The eye of a patient with age-related macular degeneration was treated with krypton laser photocoagulation and later studied histopathologically. Five months after treatment the original membrane was completely obliterated, but a separate new membrane was found, which was fed by the retinal circulation and not by the choroid. The frequency of such recurrences is not known, but they may be related to krypton laser treatment.

Electron transport system of an aerobic carbon monoxide-oxidizing bacterium

Experiments with crude extracts of Pseudomonas carboxydohydrogena revealed that a quinone is necessary for CO oxidation, and that cytochromes of the a, b, and c types and functional terminal oxidase(s) are found in cells grown on CO as the sole source of carbon and energy. CO dehydrogenase delivers electrons to the electron transport system at the level of quinone, and nicotinamide adenine dinucleotide (phosphate) is not involved in CO oxidation.

Purification and some properties of carbon monoxide dehydrogenase from Pseudomonas carboxydohydrogena

A soluble yellow CO dehydrogenase from CO-autotrophically grown cells of Pseudomonas carboxydohydrogena was purified 35-fold in seven steps to better than 95% homogeneity with a yield of 30%. The final specific activity was 180 mumol of acceptor reduced per min per mg of protein as determined by an assay based on the CO-dependent reduction of thionin. Methyl viologen, nicotinamide adenine dinucleotide (phosphate), flavin mononucleotide, and flavin adenine dinucleotide were not reduced by the enzyme, but methylene blue, thionin, and toluylene blue were reduced. The molecular weight of native enzyme was determined to be 4 x 10(5). Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed at least three nonidentical subunits of molecular weights 14,000 (alpha), 28,000 (beta), and 85,000 (gamma). The ratio of densities of each subunit after electrophoresis was about 1:2:6 (alpha/beta/gamma), suggesting an alpha(3)beta(3)gamma(3) structure for the enzyme. The purified enzyme was free of formate dehydrogenase and nicotinamide adenine dinucleotide-specific hydrogenase activities, but contained particulate hydrogenase-like activity with thionin as electron acceptor. Known metalchelating agents tested had no effect on CO dehydrogenase activity. No divalent cations tested stimulated enzyme activity. The native enzyme does not contain Ni since cells assimilated little (63)Ni during growth, and the specific (63)Ni content of the enzyme declined during purification. The isoelectric point of the native enzyme was found to be 4.5 to 4.7. The K(m) for CO was found to be 63 muM. The spectrum of the enzyme and its protein-free extract revealed that it contains bound flavin. The cofactor was flavin adenine dinucleotide based on enzyme digestion and thin-layer chromatography. One mole of native enzyme contains at least 3 mol of noncovalently bound flavin adenine dinucleotide.

Liver tests, HB-Ag and HB-Ab in asymptomatic drug addicts

One hundred eighty-eight asymptomatic addicts were studied to determine the frequency of a history of hepatitis (previous episodes of jaundice), abnormalities of liver tests (serum bilirubin, alkaline phosphatase, serum albumin, serum glutamic oxalacetic transaminase) and incidence of HB-Ag and HB-Ab. Seventy-four were white and 114 were nonwhite. A history of hepatitis was obtained in only 38%. One hundred and fifty-two of the 188 addicts (81%) had one or more abnormal liver tests. The bilirubin was abnormal in 5%, akkaline phosphatase in 28% and serum glutamic oxalacetic transaminase in 55%. HB-Ag was positive in 2.6% using radioimmunoassay and HB-Ab was found in 66%. There was a higher incidence of elevated serum glutamic oxalacetic transaminase, HB-Ab and history of hepatitis among white, compared to nonwhite addicts.