Diagnostic microbiology laboratory susceptibility test results discriminate distinctive antibiotic resistance plasmids

The sizes of the zones of inhibition around routinely tested antibiotic disks classified gentamicin-resistant isolates of Klebsiella pneumoniae from one hospital into four major antibiotype classes. From each isolate of the prevalent class (A1), two plasmids could be transferred conjugally. One carried genes for resistance to tetracycline, sulfonamides, and chloramphenicol, and for the SHV beta lactamase. The other carried genes for two aminoglycoside-inactivating enzymes, APH (3')-I and AAC (3)-III, for the TEM 1 beta lactamase, and for resistance to sulfonamides. Transconjugants of either plasmid from any A1 isolate yielded the same DNA fragments after restriction endonuclease digestion, but the two plasmids had no fragments in common. Fragments or genes from either plasmid were variously combined or lacking in plasmids from variant isolates (A2, A3, and A4). Plasmids transferable from isolates of classes B and C shared no common DNA restriction fragments with each other or with either plasmid from Class A. Fragments and genes of the plasmids from C isolates, however, were identical with those of a plasmid endemic in a nearby hospital. Routine monitoring by diagnostic microbiology laboratories of distinctive antibiotypes and of the plasmids that produce them would aid infection control and antibiotic usage policy.

Post-translational glycosylation of coronavirus glycoprotein E1: inhibition by monensin

The intracellular sites of biosynthesis of the structural proteins of murine hepatitis virus A59 have been analyzed using cell fractionation techniques. The nucleocapsid protein N is synthesized on free polysomes, whereas the envelope glycoproteins E1 and E2 are translated on the rough endoplasmic reticulum (RER). Glycoprotein E2 present in the RER contains N-glycosidically linked oligosaccharides of the mannose-rich type, supporting the concept that glycosylation of this protein is initiated at the co-translational level. In contrast, O-glycosylation of E1 occurs after transfer of the protein to smooth intracellular membranes. Monensin does not interfere with virus budding from the membranes of the endoplasmic reticulum, but it inhibits virus release and fusion of infected cells. The oligosaccharide side chains of E2 obtained under these conditions are resistant to endoglycosidase H and lack fucose suggesting that transport of this glycoprotein is inhibited between the trans Golgi cisternae and the cell surface. Glycoprotein E1 synthesized in the presence of monensin is completely carbohydrate-free. This observation suggests that the intracellular transport of this glycoprotein is also blocked by monensin.

The quantitation of cultured cellular surface coverage: applications for transparent and opaque surfaces

A planimetric technique is described for the analysis of cellular linings cultured on vascular prostheses and tissue culture plates. The method is not destructive of the cells and uses a calibrated eyepiece grid and an inverted microscope. The technique allows a rapid assessment of the percent of the prosthetic surface covered by cells, the average size of the cellular islands, and their distribution. In addition, the cells may be counted, their average surface area computed, and growth curves constructed for cells grown on tissue culture plates without the need for multiple concurrent cultures. Different cell types may be counted on the same surface. The method is more accurate than methods that require the resuspension of cells for counting, and it saves time and cells.

Changes in children's school performance as a result of education for family management of asthma

This paper describes the impact of an asthma self-management program for parents and children on the school performance and adjustment of children with asthma. Program participants were predominantly low income, minority families enrolled in four pediatric outpatient clinics. The educational content of the program was based on a needs assessment of the participants and recommendations of medical consultants. Parents and children participated separately in group sessions that focused on the development of self-management skills and problem solving. The program was organized into six themes including "how to help your child (yourself) do well in school." The program was evaluated with an experimental research design and yielded significant school related benefits. Children participating in the program maintained better grades. Math, reading and science grades were higher relative to control group children in the year following the program. Within a subgroup of children who received care from private practitioners, program children exhibited better social adjustment to school than did control group children.

Isolation of transforming sequences of two human lung carcinomas: structural and functional analysis of the activated c-K-ras oncogenes

Human lung tumors PR310 and PR371 maintained in nude mice contain activated c-K-ras oncogenes detectable by the ability of their DNAs to induce the morphological transformation of NIH 3T3 mouse fibroblasts. Using phage libraries constructed with DNA from NIH 3T3 mouse fibroblast transformants, we have isolated human sequences that span greater than 40 kilobase pairs of the c-K-ras oncogene. Based on the conservation of these human sequences in mouse fibroblast transformants, we conclude that the transforming ability of the oncogene activated in these tumors resides within a 43- to 46-kilobase-pair DNA region. No clear differences were observed between the structures of the PR310 and PR371 cloned oncogene sequences. Nucleotide sequence analysis in concert with DNA transfection experiments suggests that the PR371 oncogene has been activated by a single base change in the first exon, which results in the substitution of cysteine for glycine in position 12 of the predicted amino acid sequence. The genetic alteration responsible for the transforming activity of the PR310 oncogene, however, does not reside in the first exon. These results indicate that the activation of the c-K-ras oncogene in human lung cancer can occur by different mutational events.

Predominant integration end products of infecting bacteriophage Mu DNA are simple insertions with no preference for integration of either Mu DNA strand

The integration of 32P-labeled infecting Mu DNA into the Escherichia coli chromosome was investigated. Cleavage of the integrated Mu DNA with restriction endonuclease EcoRI, which cuts twice in the Mu genome, liberated the internal EcoRI fragment but not the left and right end fragments. The ends of the Mu genome became fused with host DNA at a variety of locations generating a smear of radioactive DNA fragments following cleavage with EcoRI. The predominant integration end products of infecting Mu DNA molecules are therefore generated by a mechanism which results in simple insertions and not cointegrates. Since predominantly simple insertions are found after infection (during lysogenization or lytic growth) but not after prophage induction, the transposition mode which is utilized appears to be a function of the source of the transposing DNA. Use of the integrated, 32P-labeled Mu DNA as a hybridization probe with the separated strands of Mu DNA or lambda phages carrying various regions of Mu showed no strand preference in the integration process. Both labeled DNA strands at both ends of the Mu genome were integrated. These results suggest the lack of a site-specific recombination site in the genome; the simple insertions which are the end products of Mu DNA integration following infection appear to be generated by a separate pathway rather than by the resolution of cointegrate structures.

Percutaneous transhepatic biliary drainage. Complications due to multiple duct obstructions

The medical histories of fifty-three consecutive patients who were scheduled for percutaneous transhepatic biliary drainage (PTBD) were reviewed for incidents of sepsis. Among the 52 patients who were successfully catheterized, there were 14 incidents of sepsis, three incidents of abscess and sepsis, and two incidents of sepsis following a pulled catheter (a total incidence of 36.5%). In 14 instances, the sepsis was attributed primarily to the presence of enteric bacteria combined with bile stasis caused by multiple duct obstruction from disseminated malignancy. The presence of bacteria in the bile of well-drained patients did not necessarily lead to sepsis. This series highlights the importance of medical alert for signs of sepsis in biliary drainage patients and suggests that external drainage is preferable in patients with incomplete emptying of the biliary system during PTBD.

Extraocular muscle surgery for dysthyroid myopathy

A series of 45 patients underwent extraocular muscle surgery for diplopia induced by dysthyroid myopathy. Two thirds (31) of the patients were female and age distribution showed a peak (47%) in the sixth decade of life. The most common deviation was pure hypotropia; a combination of hypotropia and esotropia was also frequent. Initial surgical intervention restored binocularity in primary position in 30 patients and in reading position in 27 patients. After further surgery in some cases, 40 patients eventually achieved satisfactory alignment in primary position and 36 achieved it in reading position.

Effects of cigarette smoking on fasting triglyceride, total cholesterol, and HDL-cholesterol in women

We examined the relationships of cigarette smoking with fasting triglycerides, total cholesterol, and high-density lipoprotein cholesterol (HDL-C) levels among a group of 191 white women aged 20 to 40 years. The mean triglyceride level among current smokers was 100.0 mg/100 ml and among nonsmokers was 68.4 mg/dl (p less than 0.005). Mean total cholesterol values among current smokers and nonsmokers were, respectively, 197.0 and 189.1 mg/dl (p less than 0.1). Mean HDL-C levels were 45.0 mg/dl among women who were smoking and 52.1 mg/dl among nonsmokers (p less than 0.005). Simultaneous adjustments for the effects of age, weight, height, blood glucose, resting pulse, and oral contraceptive use did not materially alter these relationships. A modest portion of the effect of cigarette smoking on risk of coronary heart disease may be explained by an adverse effect of cigarette smoking on blood lipids.

Enhanced labelling of RNA synthesized in nuclei and reduced labelling of RNA synthesized in the cytoplasm by [32P]orthophosphate in the presence of nucleosides

Labelling of cellular RNA by [32P]orthophosphate can be enhanced up to a factor of three by adding 2 to 10 X 10(-5)M of non-labelled nucleosides to the culture medium. The lag period of labelling can be reduced by a factor of two. Adenosine has the highest effect, while uridine is without effect. Labelling of viral RNA, which occurs in the cytoplasm, is reduced by nucleosides, suggesting that two precursor pools of nucleoside triphosphates are differently affected. The base composition of the labelled RNA cannot be influenced by incubation with non-labelled nucleosides. As a possible explanation for this observation a group translocation transport mechanism is discussed.

Ritodrine in the management of fetal distress

The potential value of a bolus injection of ritodrine in the management of fetal distress was examined in 24 patients. Following the injection of ritodrine, uterine activity measured over a period of 14.7 +/- 6.3 (SD) min was reduced to 22 (+/- 12.4 SD)% of the pre-existing values. The cardiotocographic tracings showed a reversion to a normal or less ominous pattern in 14 of the 16 patients where this could be evaluated. The infants in the ritodrine group took less time to establish regular respirations. The perinatal neurobehaviour in the ritodrine and control groups did not differ. Two mothers who were given ritodrine and who received atropine premedication developed tachycardia and marked systolic hypertension. The administration of a bolus of ritodrine may have a place in the management of fetal distress when caesarean section is unavoidably delayed, but atropine premedication must be avoided as the combination can lead to potentially serious cardiovascular complications.

The effectiveness of education for family management of asthma in children: a preliminary report

This paper reports preliminary findings in a convenience sample of one half the population enrolled in a study of self-management in low income families where a child has asthma. In initial evaluation data, parents participating in self-management education reported significantly less fear and anxiety associated with their children's wheezing episodes than did control families. They also reported that their children exhibited fewer signs of stress during wheezing episode. A trend toward reduced school absences and emergency room visits was noted among participating families. The actions taken by a family to manage the illness increased with the number of sessions attended.