It takes two: The relative contributions of parent versus child-led regulatory behaviours on toddler vaccination pain

BACKGROUND

Past research has established the important role of parent soothing in early childhood pain management. However, limited research has assessed children's own emerging emotion regulation strategies to reduce their pain during vaccination. The purpose of the current study was to understand the relative contributions of child-led emotion-regulation behaviours over and above parent regulatory behaviours and pre-needle distress.

METHODS

Toddler-caregiver dyads were videotaped at their 12- and/or 18-month vaccinations. Videos were coded for pain-related behavioural distress, child-led regulatory behaviours (disengagement of attention, parent-focused behaviours, and physical self-soothing), and parent regulatory/soothing behaviours (distraction, physical comfort, rocking, verbal reassurance). Pre-needle distress, followed by parent regulatory behaviours, followed by child regulatory behaviours were used as hierarchical predictors of pain regulation. Two sets of models were estimated at each age, by incorporating parent and child regulatory behaviours at 1 min and 2 min post-needle, separately.

RESULTS

At both ages, child-led parent-focused behaviours predicted less regulation. At 18 months, parent soothing behaviours (e.g. distraction, verbal reassurance, rocking) played a stronger role in regulation, however; the only behaviour that increased regulation was rocking.

CONCLUSIONS

Measuring both parent and child regulatory behaviours was important for fully understanding pain-related distress regulation. Toddlers' use of parent-focused regulatory behaviours (e.g. proximity seeking) suggests that they signal to their parent directly when they are struggling to regulate post-needle. The only parent behaviour that supported this regulation was rocking at 18 months, suggesting a greater need to understand the sensitivity of parent behaviours post-needle.

SIGNIFICANCE

To our knowledge, this is the first study to examine both parent and child regulatory behaviours following vaccination at different stages in toddlerhood. This investigation allows a deeper understanding of the dyadic nature of early childhood vaccination, as well as the evolving role of the parent through toddlerhood. Importantly, findings suggest that toddlers do not simply wait for their parents to respond to their pain post-needle and provide clear signals to show their need of support in regulation.

Detecting Stealth Dark Matter Directly through Electromagnetic Polarizability

We calculate the spin-independent scattering cross section for direct detection that results from the electromagnetic polarizability of a composite scalar "stealth baryon" dark matter candidate, arising from a dark SU(4) confining gauge theory-"stealth dark matter." In the nonrelativistic limit, electromagnetic polarizability proceeds through a dimension-7 interaction leading to a very small scattering cross section for dark matter with weak-scale masses. This represents a lower bound on the scattering cross section for composite dark matter theories with electromagnetically charged constituents. We carry out lattice calculations of the polarizability for the lightest "baryon" states in SU(3) and SU(4) gauge theories using the background field method on quenched configurations. We find the polarizabilities of SU(3) and SU(4) to be comparable (within about 50%) normalized to the stealth baryon mass, which is suggestive for extensions to larger SU(N) groups. The resulting scattering cross sections with a xenon target are shown to be potentially detectable in the dark matter mass range of about 200-700 GeV, where the lower bound is from the existing LUX constraint while the upper bound is the coherent neutrino background. Significant uncertainties in the cross section remain due to the more complicated interaction of the polarizablity operator with nuclear structure; however, the steep dependence on the dark matter mass, 1/m(B)(6), suggests the observable dark matter mass range is not appreciably modified. We briefly highlight collider searches for the mesons in the theory as well as the indirect astrophysical effects that may also provide excellent probes of stealth dark matter.

Streptozotocin-induced diabetes in rats diminishes the size of the osteoprogenitor pool in bone marrow

AIMS

Bone formation is reduced in animals and humans with type 1 diabetes, leading to lower bone mass and inferior osseous healing. Since bone formation greatly depends on the recruitment of osteoblasts from their bone marrow precursors, we tested whether experimental type 1 diabetes in rats diminishes the number of bone marrow osteoprogenitors.

METHODS

Diabetes was induced by 65 mg/kg streptozotocin and after 4 weeks, femoral bone marrow cells were extracted and cultured. Tibia and femur were frozen for further analysis.

RESULTS

The size of the osteoprogenitor pool in bone marrow of diabetic rats was significantly reduced, as evidenced by (1) lower (~35 %) fraction of adherent stromal cells (at 24h of culture); (2) lower (20-25%) alkaline phosphatase activity at 10 days of culture; and (3) lower (~40 %) mineralized nodule formation at 21 days of culture. Administration of insulin to hyperglycemic rats normalized glycemia and abrogated most of the decline in ex vivo mineralized nodule formation. Apoptotic cells in tibial bone marrow were more numerous in hyperglycemic rats. Also, the levels of malondialdehyde (indicator of oxidative stress) were significantly elevated in bone marrow of diabetic animals.

CONCLUSIONS

Experimental type 1 diabetes diminishes the osteoprogenitor population in bone marrow, possibly due to increased apoptosis via Oxidative Stress. Reduced number of osteoprogenitors is likely to impair osteoblastogenesis, bone formation, and bone healing in diabetic animals.

International consensus on (ICON) pediatric asthma

Asthma is the most common chronic lower respiratory disease in childhood throughout the world. Several guidelines and/or consensus documents are available to support medical decisions on pediatric asthma. Although there is no doubt that the use of common systematic approaches for management can considerably improve outcomes, dissemination and implementation of these are still major challenges. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), recently formed by the EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus on (ICON) Pediatric Asthma. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences, thus providing a concise reference. The principles of pediatric asthma management are generally accepted. Overall, the treatment goal is disease control. To achieve this, patients and their parents should be educated to optimally manage the disease, in collaboration with healthcare professionals. Identification and avoidance of triggers is also of significant importance. Assessment and monitoring should be performed regularly to re-evaluate and fine-tune treatment. Pharmacotherapy is the cornerstone of treatment. The optimal use of medication can, in most cases, help patients control symptoms and reduce the risk for future morbidity. The management of exacerbations is a major consideration, independent of chronic treatment. There is a trend toward considering phenotype-specific treatment choices; however, this goal has not yet been achieved.

Differential effects of prostaglandin E(2) and enamel matrix derivative on the proliferation of human gingival and dermal fibroblasts and gingival keratinocytes

BACKGROUND AND OBJECTIVE

Elevated levels of prostaglandins contribute to periodontal destruction but can impair gingival healing by affecting local fibroblasts. Enamel matrix derivative (EMD) has beneficial effects on supporting and gingival tissues. We showed that prostaglandin E(2) (PGE(2) ) inhibits the proliferation of human gingival fibroblasts (hGFs) and that EMD stimulates it. Prostaglandins and EMD may also affect skin healing by targeting dermal fibroblasts (DFs). Thus, we compared the effects of these two agents on the proliferation of hGFs, human gingival keratinocytes (hGKs) and hDFs.

MATERIAL AND METHODS

Cells from healthy human gingiva or skin were treated with PGE(2) and/or EMD, and proliferation was assessed by measuring cell number and DNA synthesis.

RESULTS

In hGFs, PGE(2) (1 μm) inhibited proliferation while EMD stimulated it. When present together, EMD abolished the PGE(2) -induced inhibition. Serum increased (by a factor of 10) the amount of phosphorylated extracellular signal-regulated kinase (p-ERK), PGE(2) reduced it (by 70-80%) and EMD restored it when present with PGE(2). Prostaglandin E(2) stimulated cAMP production in hGFs while serum or EMD did not. Enamel matrix derivative stimulated hDF proliferation, but the inhibitory effect of PGE(2) was milder than with hGFs. When present together, EMD abolished the PGE(2) -induced inhibition. Enamel matrix derivative inhibited the proliferation of primary hGKs, but PGE(2) had no effect. Finally, we found that hDFs contained about five times less prostaglandin EP(2) receptor mRNA than hGFs, while hGKs contained none.

CONCLUSION

Prostaglandin E(2) inhibits and EMD stimulates hGF proliferation via distinct pathways. The different sensitivities of hDFs and hGKs to PGE(2) can be explained by the levels of EP(2) expression.

GELRITE as an Agar Substitute in Bacteriological Media

GELRITE gellan gum (formerly known as PS-60 and S-60) is a new naturally derived, highly purified polysaccharide which displays several interesting properties, including selfgelling. The suitability of GELRITE as an agar substitute was tested by evaluating the performance of several media selected from among those most commonly used in the isolation, identification, and enumeration of microorganisms in clinical laboratories. Fifty different bacterial species previously implicated in human infections served as test strains. On the basis of the various parameters considered, namely, colony characteristics, biochemical reactions, hemolytic patterns, and plating efficiency, media gelled by agar and by GELRITE compared quite favorably.

Concept and computational design for a bioartificial nephron-on-a-chip

A MEMS-based, (Micro Electro Mechanical System) bioartificial device is proposed for replicating the function of a single nephron. Consistent with the anatomy and physiology of humans, our device has 3 distinct sections, replicating the function of the glomerulus, the proximal tubule, and the loop of Henle. Construction of a bioartificial loop of Henle in particular requires control of diffusion-scale features. The proposed device can be built using existing microfabrication technologies and populated with various renal cell types. A computational model is also developed to analyze the coupled, multiphase mass transport in this system. Using the model, a design is generated with flow and solute transport properties matching those of the human nephron.

Persistence of rhinovirus RNA after asthma exacerbation in children

BACKGROUND

Rhinoviruses (RVs) are believed to cause most asthma exacerbations but their role in the severity of acute asthma and subsequent recovery of airway function is not defined. The importance of atopy in virus-host interactions is also not clear.

OBJECTIVE

We postulated that RV infection and atopic skin prick responses influence the severity of asthma exacerbations as measured by peak expiratory flow (PEF).

METHODS

Patients aged 4-12 years admitted with acute severe asthma to a hospital emergency room (ER) were recruited. PEF measurements were obtained and nasal aspirates (NA) were taken. Atopy was diagnosed by skin prick responses to allergen and the presence of RV RNA and respiratory syncytial virus (RSV) RNA in NAs was detected using validated PCR assays. Patients were restudied after 6 weeks and after 6 months.

RESULTS

Fifty children with acute asthma (mean age+/-SD, 7.4+/-2.7) were enrolled; atopy was present in 37 (74%). RV RNA was detected in 41 (82%) and RSV RNA in six (12%) subjects. After 6 weeks 41 patients were restudied and RV RNA was again detected in 18 (44%). RV RNA was detected after 6 months in four of 16 patients restudied (25%; P=0.008 vs. ER) and in two of nine children from a control group with stable asthma (22%; P=0.009 vs. ER). Overall PEF measurements were reduced in asthmatics admitted to ER (% predicted, 63.4+/-16.4%) but did not differ between patients with RV RNA, RSV RNA or neither virus present. In subjects with RV RNA detectable in ER and after 6 weeks, measurements of PEF in ER were significantly lower than in patients in whom RV RNA was present in ER but absent after 6 weeks (P=0.009). Regression analysis linked persistence of RV RNA, but not skin prick responses to allergen, to severity of PEF reductions in ER.

CONCLUSION

RV RNA was detectable in >40% of asthmatic children 6 weeks after an acute exacerbation. Asthma exacerbations were more severe in patients with persistence of RV RNA suggesting that the severity of acute asthma may be linked to prolonged and possibly more severe RV infections.

Socioeconomic deprivation and asthma prevalence and severity in young adolescents

This study used the international study of asthma and allergies in childhood (ISAAC) to investigate the association between asthma and socioeconomic deprivation among young adolescents in Cape Town, South Africa. The completed ISAAC written and video questionnaires of 4,706 13-14-yr-old school pupils were used. The prevalence of asthma symptoms was analysed by a local index of socioeconomic deprivation, based on residential location and defined on a 10-category scale from least to most deprived. Linear trends were examined visually and the prevalence odds ratio was used to summarize overall trends. In general, the least socioeconomically deprived pupils reported higher prevalences of asthma symptoms "ever" and "in the last 12 months". In contrast, the most socioeconomically deprived pupils reported higher asthma-symptom occurrence monthly or more frequently in the previous 12 months. A subgroup of pupils from low-income areas commuting to better-off schools showed the highest symptom prevalences. The findings are consistent with a model in which an increase in the incidence of asthma is driven by factors associated with improved social circumstances, whereas severity is determined by factors associated with poverty. The impact of social mobility on asthma, including reporting of symptoms, deserves closer study.

Household smoking and bronchial hyperresponsiveness in children with asthma

This study investigated whether household environmental tobacco smoke (ETS) exposure is associated with increased bronchial hyperresponsiveness (BHR) in children with asthma. Two hundred forty-nine children, ages 7-11 years, sampled from a larger group with reported asthma or multiple asthma symptoms identified in a community survey in Cape Town, underwent histamine challenge testing and had urinary cotinine measured. Parents were interviewed for information on smoking habits and a variety of covariates. Children with asthma whose mothers smoked had a lower frequency of BHR than asthmatic children of nonsmoking mothers, particularly if the mother smoked > or = 15 cigarettes daily. BHR was also less common among children sharing a house with four or more smokers vs. fewer or none. BHR was unrelated to paternal smoking. In contrast, FEV1 was lower among children whose mothers currently smoked. The findings do not support a mechanism whereby ETS exposure aggravates existing childhood asthma by increasing BHR. This association may be masked, however, by the degree to which mothers of asthmatic children adjust their smoking. The results are consistent with an adverse effect of maternal smoking on lung function in asthmatic children.

Dorsal and intermediate neuronal cell types of the spinal cord are established by a BMP signaling pathway

We have studied the role of Bmp signaling in patterning neural tissue through the use of mutants in the zebrafish that disrupt three different components of a Bmp signaling pathway: swirl/bmp2b, snailhouse/bmp7 and somitabun/smad5. We demonstrate that Bmp signaling is essential for the establishment of the prospective neural crest and dorsal sensory Rohon-Beard neurons of the spinal cord. Moreover, Bmp signaling is necessary to limit the number of intermediate-positioned lim1+ interneurons of the spinal cord, as observed by the dramatic expansion of these prospective interneurons in many mutant embryos. Our analysis also suggests a positive role for Bmp signaling in the specification of these interneurons, which is independent of Bmp2b/Swirl activity. We found that a presumptive ventral signal, Hh signaling, acts to restrict the amount of dorsal sensory neurons and trunk neural crest. This restriction appears to occur very early in neural tissue development, likely prior to notochord or floor plate formation. A similar early role for Bmp signaling is suggested in the specification of dorsal neural cell types, since the bmp2b/swirl and bmp7/snailhouse genes are only coexpressed during gastrulation and within the tail bud, and are not found in the dorsal neural tube or overlying epidermal ectoderm. Thus, a gastrula Bmp2b/Swirl and Bmp7/Snailhouse-dependent activity gradient may not only act in the specification of the embryonic dorsoventral axis, but may also function in establishing dorsal and intermediate neuronal cell types of the spinal cord.

Early use of inhaled nedocromil sodium in children following an acute episode of asthma

BACKGROUND

Current guidelines on the treatment of childhood asthma recommend the introduction of an anti-inflammatory drug in children who have persistent symptoms and require regular treatment with a bronchodilator. The efficacy and safety of inhaled nedocromil sodium (Tilade Mint aerosol) administered using a Fisonair spacer at a dose of 4 mg three times daily was compared with placebo in the treatment of asthmatic children aged 6-12 years who are symptomatic and recovering from an acute exacerbation of asthma.

METHODS

A group comparative, double blind, placebo controlled trial was performed in children who were recovering from an acute episode of asthma following treatment in the emergency department of the hospital or in children referred from their general practitioner following a wheezing episode and documented evidence of at least two previous episodes of wheezing. A two week baseline period on existing bronchodilator treatment was followed by a 12 week treatment period on either nedocromil sodium (2 mg/puff) or placebo. Both treatments were administered using a Fisonair spacer at a dose of two puffs three times daily. Changes from baseline values in daytime asthma and night time asthma symptom scores, usage of rescue bronchodilators, mean peak expiratory flow (PEF) recorded twice daily on diary cards, patients' opinion of treatment, and withdrawals due to treatment failure were measured during the primary treatment period (last six weeks of treatment).

RESULTS

One hundred and forty two children aged 6-12 years entered the baseline period. Sixty three were withdrawn due to failure to meet the entry criteria (18) or the criteria for asthma symptom severity (15) or reversibility (9), because they developed uncontrolled asthma (2), because they took disallowed treatment (2), or for other non-trial related reasons (17). Seventy nine patients (46 boys) of mean age 8. 8 years entered the treatment period. There were significant differences in the changes from baseline values during the last six weeks of treatment in favour of nedocromil sodium compared with placebo in the primary variables of daytime asthma and night time asthma, morning and evening PEF, and the usage of rescue inhaled bronchodilators; 53% of patients reported nedocromil sodium to be very or moderately effective compared with 44% placebo. Improvement in asthma symptoms, PEF, and reduction in use of rescue bronchodilators did not reach statistical significance until after six weeks of treatment. Twenty two patients were withdrawn or dropped out during the treatment phase, 12 due to uncontrolled asthma or persistence of asthma symptoms, four due to suspected adverse drug reactions (nedocromil sodium 3 (headaches 2, angio-oedema/urticaria 1), placebo 1(persistent cough)), and six due to non-treatment related reasons. Seventy one adverse events were reported by 27 patients in the nedocromil group and 75 by 30 patients in the placebo group.

CONCLUSIONS

Asthma symptoms, use of bronchodilators, and lung function can be improved significantly in children recovering from an acute exacerbation of asthma or wheeze and currently receiving treatment with bronchodilators alone by the addition of inhaled nedocromil sodium at a dose of 4 mg three times daily administered using a Fisonair holding chamber.

Exposure to peanuts in utero and in infancy and the development of sensitization to peanut allergens in young children

This study attempted to determine the underlying factors that may influence the development of peanut sensitization in young children in South Africa. One of our objectives was to ascertain whether the consumption of peanuts or peanut-containing foods during pregnancy and lactation by mothers from atopic families impacted upon the development of an allergic response to peanuts in the child. Forty-three children between the ages of 0 and 3 yr participated in this study. There were 25 peanut-sensitized subjects and 18 control subjects (children sensitized to milk and/or egg, but not to peanuts). A significant association was found between peanut sensitization and sensitivity to soya (p=0.0002), wheat (p=0.03), and cod fish. We found that mothers who consumed peanuts more than once a week during pregnancy were more likely to have a peanut-allergic child than mothers who consumed peanuts less than once a week (odds ratio=3.97, 98% confidence interval 0.73-24). Peanuts or peanut butter was introduced into the child's diet from a significantly younger age in the peanut-allergic subjects (p<0.03). There was a positive correlation in the peanut-allergic subjects between age of introduction of peanuts and age at the onset of symptoms (r=0.63). Exclusive breast feeding did not protect against the development of peanut sensitization. Peanut allergy is associated with an increased risk of sensitization to other foods. It is more likely to occur if mothers eat peanuts more frequently during pregnancy and introduce it early to the infant's diet. These features highlight potentially avoidable factors that might prevent sensitization.

Underrecognition and undertreatment of asthma in Cape Town primary school children

BACKGROUND

In view of the high local prevalence of asthma, the extent of recognition and appropriate management of childhood asthma was studied in a large suburban area of Cape Town.

DESIGN

Cross-sectional study based on random community sample of schools.

METHOD

1,955 parents of sub B pupils from 16 schools completed a questionnaire, followed by: (i) an interview of the parents of 348 symptomatic children; and (ii) bronchial responsiveness testing on 254 children. The final case group consisted of 242 children with reported asthma or multiple asthma symptoms on both questionnaires. Children in whom asthma was acknowledged were compared with those in whom it was not.

RESULTS

Overall, any past or current ('ever') asthma was acknowledged by respondents in only 53% of the children, and current asthma in only 37.1%. While most children had received treatment in the previous 12 months, 66.1% of the recognised group were on current treatment (23.2% on daily treatment), compared with 37% of the unrecognised group (3% daily). Salbutamol and theophylline syrups were the most common types of medication, while inhalers and anti-inflammatory medications were underused. Only a minority of parents reported the child ever having used a peak flow meter, or volunteered knowledge of preventive measures. Current treatment, and to a lesser degree recognition of asthma by parents, were more common among children on medical aid and of higher socio-economic status.

CONCLUSIONS

These findings suggest that ways need to be found: (i) to increase the use of current asthma treatment guidelines by practitioners; (ii) to provide access to comprehensive care by children not on medical aid; and (iii) to improve education of parents in home management measures such as severity assessment and avoidance of smoking, allergen and dietary triggers.

Students' educational activities during clerkship

PURPOSE

To quantify the educational activities and types of teachers that medical students had in third-year clerkships at community-based teaching hospitals.

METHOD

In October-November 1992, 201 students in third-year medical clerkships at nine community-based hospitals completed a log that recorded the primary activity, site, and educator and method of education (for teaching or supervised activities) for each 15-minute interval of a 24-hour day. Each hospital offered at least three of the clerkships studied: medicine, obstetrics-gynecology (ob-gyn), pediatrics, psychiatry, and surgery. Statistical comparisons of the clerkships were done with chi-square analysis and one-way analysis of variance.

RESULTS

The students received 6.5 hours a day of teaching with an instructor and committed an additional 4.9 hours to clerkship-related learning. Nearly 75% of the teaching fell to full-time faculty members and residents. In just over half of their educational activities the students participated with other learners, such as residents. The clerkships did not differ significantly in the amounts of formal teaching given; however, medicine did significantly more informal teaching, and surgery and ob-gyn did significantly more supervised practice.

CONCLUSION

This preliminary study quantified medical students' educational activities in 1992 during third-year clerkships and provides baseline data describing these activities and the educators involved. Some findings may not be replicable, however, with the increasing demands of full-time faculty members in inpatient and outpatient settings and the shifting emphases in how and where residents provide instruction. Another study such as this one would help assess the effects on medical education of changes in the health care environment.

Risk factors for childhood asthma and wheezing. Importance of maternal and household smoking

To identify modifiable risk factors for wheezing illness in childhood, the associations between current asthma or wheezing and factors such as household smoking, damp and dietary salt preference were measured in a questionnaire-based prevalence study of schoolchildren 7 to 9 yr of age in Cape Town. In a random sample of 15 schools, questionnaires were completed by parents of 1,955 children, from which 368 cases and 294 controls were selected on the basis of reported asthma diagnosis or symptoms. Urinary cotinine concentrations were measured, and the parents were interviewed. An exposure-response relationship between the urinary cotinine creatinine ratio and asthma/wheeze was observed. In multivariate analysis, predictors of asthma/wheeze were hay fever (odds ratio [OR] - 5.30; 95% confidence interval [CI] = 3.16 to 8.89), eczema (OR = 2.19; 95% CI = 1.33-3.62), parental asthma (OR = 1.77; 95% CI = 1.11 to 2.84), absence of paternal contribution to income (OR = 1.72; 95% CI = 1.17 to 2.54), maternal smoking in pregnancy (OR = 1.87; 95% CI = 1.25 to 2.81), and each additional household smoker (OR = 1.15; 95% CI = 1.01 to 1.30). Findings were similar, with higher odds ratios for most variables, except number of household smokers, when the group was restricted to children with parent-reported asthma. The findings confirm that household smoking is an important modifiable risk factor in asthma/wheeze among young schoolchildren, and they suggest that maternal smoking in pregnancy and current household exposure are independent contributors to this effect.

The cost of third-year clerkships at large nonuniversity teaching hospitals

BACKGROUND

Large nonuniversity teaching hospitals are major providers of the clinical training component of undergraduate medical education, yet little information is available to policymakers, participating hospitals, or sponsoring medical schools on the institutional costs of this service.

OBJECTIVE

To determine the costs associated with teaching students in required third-year clerkships for a group of large nonuniversity teaching hospitals.

SETTING/PARTICIPANTS

A total of 201 medical students from nine large nonuniversity teaching hospitals affiliated with nine medical schools that participate in required third-year clerkships.

METHODS

During a typical week, students completed 24-hour time and activity logs that classified each activity, instructor, and audience. From these logs, the number of teaching hours by full-time faculty and others were estimated and costs were calculated.

RESULTS

Full-time faculty provided a mean of 0.242 h/d of formal teaching, 0.326 h/d of informal teaching, and 0.581 h/d of supervised patient care training per student, an estimated direct faculty cost of $412 per week per student. The cost of direct and indirect departmental and academic administration, as well as other direct out-of-pocket medical education costs, added $250 per week per student. The average annual clinical program cost of third-year clerkships to nonuniversity hospitals and their full-time faculties was $31,776 per student. This figure does not include the substantial contributions of teaching by other than paid faculty (eg, volunteer physicians and residents), which was important in terms of activity and service provided.

CONCLUSIONS

Direct and indirect costs of third-year medical student education for most hospitals in this study was more than $1 million per year, well in excess of the average support provided by sponsoring medical schools.

Uterine cervical lymphoepithelial-like carcinoma. Absence of Epstein-Barr virus genomes

A poorly differentiated squamous cell carcinoma of the cervix with marked lymphoplasmacytic stromal infiltration is described in a 21-year-old black woman who had postcoital bleeding. Histologic features were strikingly similar to the classic lymphoepithelioma of the nasopharynx. Serologic evidence for remote Epstein-Barr virus infection was present. However, polymerase chain reaction amplification and hybridization of DNA extracted from fresh-frozen tumor tissue failed to identify Epstein-Barr virus genomic DNA. No human papillomavirus DNA was detected by polymerase chain reaction amplification. The histologic and Epstein-Barr virus results of the uterine cervical lymphoepitheliomal-like carcinoma were compared to the classic nasopharyngeal lymphoepithelioma and to similar tumors studied from other anatomic sites.

Needle aspiration of peritonsillar abscess in children

Needle aspiration for the treatment of peritonsillar abscess was assessed in 43 consecutive children aged 7 to 18 years (mean age, 13.9 +/- 2.5 years) during the 3-year period from 1988 through 1991. A positive aspirate was obtained in 31 (76%) of the 41 patients who cooperated for needle aspiration; a mean of 2.9 +/- 1.9 mL of pus was withdrawn. Of the 31 children with a positive aspirate, in 27 (87%) the abscess resolved, two (6%) required a second aspiration for resolution, and two (6%) underwent immediate tonsillectomy for persistent abscess. Of the 10 children (24%) with negative aspirations, in six (60%) the abscess resolved with antibiotic treatment alone, three (30%) underwent immediate (quinsy) tonsillectomy, and in one (10%) the abscess spontaneously drained. No bleeding, airway obstruction, or anesthetic complications occurred. Needle aspiration of peritonsillar abscess in children, with tonsillectomy reserved for nonresponders, appears to be an efficacious and safe method of treatment.

Distribution of a neutral cardioplegic vehicle during the development of ischemic myocardial contracture

During prolonged ischemic cardiac arrest successful myocardial protection depends upon uniform delivery of cardioplegic solutions to all regions of the heart. Accordingly, we studied the regional and transmural distribution of a neutral crystalloid (dextran-saline) solution during normothermic (37 degrees C) ischemia in 18 isolated blood-perfused dog hearts (isovolumic left ventricle). In the baseline state, coronary perfusion pressure was 100 mmHg. At the onset of ischemia and every 15 min throughout ischemia, we infused 100 ml of crystalloid solution (37 degrees C) at a perfusion pressure of 100 mmHg and the distribution of crystalloid solution was assessed (radioactive microsphere technique). The hearts were reperfused after 60 min (n = 9) or 90 mins (n = 9) of ischemia. In the baseline pre-arrest state the left ventricle (LV) received 67 +/- 1.0% of the total coronary blood flow; the LV subendocardial to subepicardial flow ratio was 1.33 +/- 0.18, the LV end diastolic pressure was 7.5 +/- 0.4 mmHg, and mean transmural myocardial adenosine triphosphate (ATP) was 16.4 +/- 1.1 microM/g DW. At the onset and throughout the first 45 mins of ischemia (n = 9), regional and transmural distribution of the crystalloid solution was similar to that of coronary blood flow during the baseline state; there was no change in LV end diastolic pressure, but there was a moderate fall in ATP content (7.26 +/- 1.6 micron/g DW). After 75 mins of ischemia (n = 9), despite the development of ischemic contracture (LV end diastolic pressure exceeded 20 mmHg in all 9 hearts) and marked ATP depletion (2.76 +/- 0.5 microM/g DW), there was an increase in crystalloid solution delivery to the LV as a whole and the subendocardium in particular (the LV received 82 +/- 2.0% and the subendocardial to subepicardial flow ratio was 1.75 +/- 0.1). Even in a subgroup with severe contracture during ischemic arrest (LV end diastolic pressure greater than 60 mmHg, n = 4) there was no reduction in crystalloid solution delivery. Thus, the presence of ischemic contracture does not preclude delivery of crystalloid solution to the LV subendocardium.

The influence of pressure overload left ventricular hypertrophy on diastolic properties during hypoxia in isovolumically contracting rat hearts

We tested the hypothesis that there is an enhanced susceptibility in hypertrophied cardiac muscle to develop decreased diastolic distensibility of the left ventricle in response to hypoxia. The effects of brief hypoxia (3 minutes) were studied in rats with and without chronic left ventricular pressure overload hypertrophy using an isolated buffer-perfused and isovolumic (balloon-in-left ventricle) heart preparation with excised pericardium and vented right ventricle. We compared hypertrophied hearts from hearts from hypertensive uninephrectomized Wistar-Kyoto rats (n = 12) with normotensive uninephrectomized age-matched controls (n = 13). Coronary flow was held constant and adjusted so that an identical flow per gram left ventricular weight was achieved in both groups. The left ventricular balloon volume was adjusted to produce an initial left ventricular end-diastolic pressure of 10 mm Hg in both groups and was held constant thereafter so that changes in left ventricular end-diastolic pressure during hypoxia represented changes in diastolic chamber distensibility. Under aerobic conditions, left ventricular systolic pressure was 66% higher in the hypertrophied hearts than in the controls, but there was no difference in the rate or extent of left ventricular relaxation as estimated by the exponential time constant of pressure decay and the asymptote to which pressure decayed. In response to hypoxia, left ventricular end-diastolic pressure was significantly higher in the hypertrophied hearts than in the controls (37 +/- 5 vs. 22 +/- 5 mm Hg, P less than 0.001). In response to hypoxia, the rate of left ventricular relaxation was depressed to a comparable degree in both groups, but there was a greater upward shift in the asymptote to which pressure decayed in the hypertrophied hearts. Hypoxia-induced coronary vasodilation as assessed by the change in coronary vascular resistance was similar in the hypertrophied and control hearts (2.9 +/- 0.5 vs. 2.3 +/- 0.9 mm Hg/[(ml/min)/g], NS). The degree of hypoxia-induced anaerobic metabolism as estimated by the coronary arterial-venous lactate concentration difference was also similar in both groups (-0.72 +/- 0.23 vs. -0.73 +/- 0.16 mM/liter, NS). It is concluded that brief hypoxia results in a greater decrease in diastolic distensibility of the left ventricle in the presence of chronic pressure overload hypertrophy than in its absence.

Tentative interpretive criteria for in vitro antibacterial susceptibility testing with imipenem

Imipenem is a member of a new class of highly potent beta-lactam antibiotics, carbapenems, with a very broad antibacterial spectrum. This study was undertaken to determine tentative interpretive criteria for in vitro susceptibility testing with 10-micrograms imipenem disks. A careful examination of the zone diameters and the corresponding MICs for 489 clinical isolates by regression-line analysis and the error rate-bounded classification scheme suggested the following guidelines: greater than or equal to 16 mm with an MIC correlate of less than or equal to 4 micrograms/ml for susceptible, 14 to 15 mm (8 micrograms/ml) for moderately susceptible, and less than or equal to 13 mm (greater than or equal to 16 micrograms/ml) for resistant. Lack of cross-resistance between imipenem and broad-spectrum cephalosporins such as cefotaxime and ceftazidime argues against their use as class disks to predict in vitro susceptibility of bacterial species to carbapenems.

Simultaneous expression of early and late histone messenger RNAs in individual cells during development of the sea urchin embryo

The transition from early (E) to late (L) histone gene expression in developing sea urchin (Strongylocentrotus purpuratus) embryos was examined for H2B, H3, and H4 mRNAs by in situ hybridization of class-specific probes. Hybridization patterns indicate that the shift from E to L mRNAs occurs gradually and simultaneously in all blastomeres. Thus, during the transition the ratio of L to E mRNAs is similar in most cells. This suggests that no sudden changes in histone composition occur in individual cells which might be related to alterations in gene expression associated with differentiation of cell lineages. Around the midpoint of the transition, clusters of cells progressively appear which contain little, if any, E or L histone mRNA. This modulation of expression is coordinated for the three late genes examined because most individual cells contain either high or low levels of all three mRNAs. At blastula stage these clusters of unlabeled cells appear to be randomly distributed throughout the embryo. Subsequently the unlabeled regions expand and are found predominantly in aboral ectoderm as these cells cease to divide. Thus, the L/E histone mRNA ratio is not differentially regulated in diverse cell lineages, and the major differences in total histone mRNA content among individual cells may be related to cell cycle and/or the cessation of division.

Evaluation of three broth disk methods for testing the susceptibility of anaerobic bacteria to imipenem

Imipenem is a member of a new class of highly potent beta-lactam antibiotics, carbapenems, with an antibacterial spectrum that includes nearly all currently known aerobic and anaerobic bacterial species of clinical significance. Although relatively stable in most standard laboratory media used for antimicrobial susceptibility testing, imipenem undergoes rapid inactivation in thioglycolate broth, a recommended medium for susceptibility testing of anaerobic bacteria by the broth disk method. In the current study, a panel of 36 anaerobic bacteria consisting of 28 clinical isolates and eight quality control strains was used to determine the suitability and accuracy of the broth disk methods with brain heart infusion, Schaedler, and anaerobic broths, in comparison to the reference agar dilution method, for the anaerobic susceptibility testing of imipenem. To achieve single test concentrations of approximately 8, 16, and 64 micrograms/ml for imipenem, cefoxitin, and piperacillin, respectively, which correspond to the MIC breakpoints of the test drugs, four 10-microgram imipenem disks, three 30-microgram cefoxitin disks, and three 100-microgram piperacillin disks were used in 5 ml of broth. The correlation between the reference agar dilution method and each of the three broth disk elution procedures evaluated was excellent, for imipenem (100% agreement) and somewhat less so for cefoxitin and piperacillin. Therefore, brain heart infusion, Schaedler, and anaerobic broths, but not thioglycolate broth, are suitable for anaerobic susceptibility testing of imipenem by the disk elution method.

Comparative ototoxicity of netilmicin, gentamicin, and tobramycin in cats

Netilmicin, a semisynthetic aminoglycoside antibiotic, is less ototoxic in a variety of species than other aminoglycosides currently in therapeutic use. In this study, mixed-breed cats (four/group) were given daily sc injections of netilmicin (20, 40, and 80 mg/kg), gentamicin (20 and 40 mg/kg), or tobramycin (20, 40, and 80 mg/kg) for up to 30 weeks or until ototoxicity was observed. The animals were examined throughout the study for effects on cochlear and vestibular function. Hematologic, serum chemical, and drug-serum (24-hr postdose) assays were performed at approximate monthly intervals during the dosing period. The cochleae, kidneys, and liver were examined microscopically. The mean number of dose days required to produce vestibulotoxic effects, demonstrated by impaired righting reflex or locomotor ataxia, was from 41 to 61 in cats dosed with tobramycin (40 and 80 mg/kg) or gentamicin. No vestibular dysfunction was observed in any of the netilmicin 20-mg/kg-dosed cats, in two cats each of the tobramycin 20-mg/kg and netilmicin 40-mg/kg groups, and in one netilmicin 80-mg/kg-dosed animal. Histologic examination of the cochleae revealed degeneration of the hair cells and supporting sensory structures in the majority of cats dosed with gentamicin at 20 and 40 mg/kg and tobramycin at 40 and 80 mg/kg. Less than 50% of the tissues from cats of the tobramycin 20-mg/kg and netilmicin 40- and 80-mg/kg-dosed groups had similar degenerative cochlear changes. No cochlear damage was noted in any of the cats given netilmicin at 20 mg/kg. Results of the clinical laboratory determinations were generally unremarkable. Proximal tubular degeneration was the principal finding observed in the kidneys of the animals. Under the conditions of this study, at least a twofold (vestibular) to fourfold (cochlear) relative safety margin for ototoxicity was established in favor of netilmicin over tobramycin and gentamicin.

In vitro antibacterial activity of norfloxacin and other agents against ocular pathogens

302 clinical isolates representing 16 bacterial species most often implicated in ocular infections were tested in vitro against norfloxacin and a panel of antibacterial agents. On the basis of the 90% minimal inhibitory concentration (MIC90) data, norfloxacin was 4-32 times more active than the next best antimicrobial tested against Citrobacter freundii, Escherichia coli, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Haemophilus influenzae, Neisseria gonorrhoeae and Staphylococcus epidermidis, with overall MIC90 less than or equal to 1 mg/l. Norfloxacin was equal in activity to polymyxin B against Klebsiella pneumoniae (MIC90 = 1 mg/l), and it ranked second to both polymyxin B against Pseudomonas aeruginosa and cotrimoxazole against Staphylococcus aureus, (MIC90 = 2 mg/l in each case). Along with neomycin and cotrimoxazole, norfloxacin (MIC90 = 1 mg/l) ranked second to gentamicin and tetracycline against Moraxella species. Compared to erythromycin (MIC90 less than or equal to 0.125 mg/l), norfloxacin (MIC90 less than or equal to 16 mg/l) was considerably less active against streptococci. Overall, norfloxacin was the most active agent in both potency and antibacterial spectrum against the test organisms. These results suggest the potential use of norfloxacin in the treatment of superficial bacterial infections of the eye.

Acute severe asthma. A prospective study of the precipitating factors in 40 children

A prospective study was undertaken to determine the factors precipitating acute severe asthma in children attending the Red Cross War Memorial Children's Hospital, Cape Town. A comparison in terms of recent exposure to possible precipitating factors was made between 40 known asthmatics presenting with acute severe asthma and 40 known asthmatics who were clinically well. Exposure to known allergens had occurred in 7 cases. The time of onset of symptoms bore no relationship to meteorological changes in temperature, humidity or average pressure. Drug compliance in both groups was of the order of 50%. The majority of severe asthma attacks were associated with infection of the respiratory tract. The importance of infection as a precipitating factor in a severe asthma attack is discussed with reference to the cholinergic, adrenergic and immunological mechanisms.

Effectiveness of the antimicrobial removal device, BACTEC 16B medium, and thiol broth in neutralizing antibacterial activities of imipenem, norfloxacin, and related agents

The Antimicrobial Removal Device (ARD), BACTEC 16B medium, and Thiol broth were evaluated for their effectiveness in reducing the activity of imipenem (IPM), cefoxitin, moxalactam, and ceftazidime in blood samples. In addition, the capability of the ARD and Thiol broth to bind norfloxacin and the ARD to bind oxolinic and nalidixic acids in urine samples was investigated. At the highest concentrations of the drugs tested (32 micrograms/ml for the four beta-lactams and 256 micrograms/ml for the three quinolinecarboxylic acids), there was at least a 95% reduction in the in vitro activity of each of the antibacterial agents for treated versus untreated samples. Of the compounds tested in the ARD system, the organic acids were more completely removed than were the beta-lactams. The Thiol broth was more effective than the ARD and the BACTEC 16B medium in inactivating imipenem, but it had no effect on the antibacterial activity of norfloxacin.

Tentative interpretive standards for disk diffusion susceptibility testing with norfloxacin (MK-0366, AM-715)

Norfloxacin is a new orally absorbed quinoline derivative structurally related to nalidixic acid but showing an expanded antibacterial spectrum which includes Enterobacteriaceae, Pseudomonas aeruginosa, Streptococcus faecalis, and staphylococci, among other susceptible bacterial species. The application of the regression line and error rate-bounded methods of analysis to the minimal inhibitory concentration and zone size data collected on 413 clinical isolates favored the selection of a 10-micrograms disk content and the adoption of the following interpretive zone size breakpoints for antimicrobial susceptibility testing with norfloxacin: greater than or equal to 17 mm for susceptible, 13 to 16 mm for intermediate, and less than or equal to 12 mm for resistant categories. It is proposed that isolates with minimal inhibitory concentrations of less than or equal to 16 and greater than or equal to 32 micrograms/ml be considered susceptible and resistant to norfloxacin, respectively. Differences in the antibiotic disk contents and in vitro antibacterial spectra and pharmacokinetic properties, together with the much lower rates of cross-resistance reported between norfloxacin and related drugs, strongly argue against the use of the "class disk" concept in this instance and suggest that the 10-micrograms norfloxacin susceptibility disk should be tested separately.

In vitro antibacterial activity of norfloxacin (MK-0366, AM-715) and other agents against gastrointestinal tract pathogens

A comparison was made of the in vitro activities of norfloxacin and of nine other orally administered antibacterial agents against 180 clinical isolates representing the bacterial species most frequently implicated in infections of the gastrointestinal tract in humans. The 90% minimal inhibitory concentrations showed norfloxacin to be 4, 15, 4, 17, 17, 17, and 33 times more active than the next best compound tested against Campylobacter fetus subsp. jejuni, Escherichia coli, Salmonella spp., Shigella spp., Vibrio cholerae, Vibrio parahaemolyticus, and Yersinia enterocolitica, respectively, with an overall 90% minimal inhibitory concentration of less than or equal to 0.5 micrograms/ml. Norfloxacin was least active against Clostridium difficile (90% minimal inhibitory concentration, 128 micrograms/ml). These results should encourage further evaluation of norfloxacin as a potential chemotherapeutic agent in the treatment of enteric bacterial infections for which antibiotic therapy is indicated.

Quaternary heterocyclylamino beta-lactams. V. L-640,876 treatment of induced enterotoxigenic colibacillosis (scours) in calves and piglets

A new semisynthetic cephalosporin antibiotic designated L-640,876, 7-beta-(1-benzylpyridinium-4-yl)amino-3-[( (1-methyl-1H-tetrazol-5-yl)thio] methyl)ceph-3-em-4-carboxylate, was highly active in vitro against 110 enteropathogenic strains of Escherichia coli and Salmonella species of animal origin. The MIC90 was 0.125 microgram/ml for the E. coli strains, 2 micrograms/ml for the S. choleraesuis strains and 4 micrograms/ml for the S. typhimurium strains. In colostrum-fed calves infected with E. coli strain B44, L-640,876 administered by gavage at 30 mg/calf (0.67 mg/kg) twice a day for 3 days, starting at 20-hour post-inoculation, eliminated the diarrhea and reduced the mortality from 82% in the infected, nonmedicated calves to 11% in the infected, medicated calves (P less than 0.05). In colostrum-fed piglets infected with E. coli strain P155, L-640,876 administered by gavage at 12.5 or 20 mg/piglet (10 or 16 mg/kg) twice a day for 3 days, starting at 6-hour post-inoculation, eliminated the diarrhea and reduced the mortality from 79% in the infected, nonmedicated to 25% in the infected, medicated piglets (P less than 0.05). Thus, L-640,876 was highly effective in restoring the calves and piglets to good health by eliminating diarrhea and reducing mortality.

Quaternary heterocyclylamino beta-lactams. II. The in vitro antibacterial properties of L-640,876, a new type of beta-lactam antibiotic

A new semisynthetic cephalosporin antibiotic designated 7-beta-(1-benzylpyridinium-4-yl)-amino-3-[( (1-methyl-1H-tetrazol-5-yl) thio]methyl)ceph-3-em-4-carboxylate (L-640,876) was compared for antibacterial activity in vitro with mecillinam, cefoxitin and cefotaxime. The antibacterial spectrum of L-640,876 and the effect of culture medium composition and inoculum size on activity are most similar to those of mecillinam. In some cases the inoculum effect on MICs correlated with instability of the compound to certain beta-lactamases and in others to the presence of ionized compounds such as sodium chloride in the medium. On balance, L-640,876 was superior to mecillinam in potency and breadth of spectrum.

Comparison of the antibacterial activity of norfloxacin (MK 0366, AM 715), a new organic acid, with that of other orally absorbed chemotherapeutic agents

425 randomly selected, fresh clinical isolates were tested for susceptibility to norfloxacin and other orally absorbed agents, i.e. amoxicillin, ampicillin, carbenicillin (available commercially as the indanyl ester), cefaclor, cinoxacin, erythromycin, nalidixic acid, penicillin G, tetracycline, trimethoprim and co-trimoxazole. The results have shown norfloxacin to be the most potent agent in vitro against representative members of the family Enterobacteriaceae, Staphylococcus aureus, Pseudomanas aeruginosa, Acinetobacter spp., Neisseria gonorrhoeae and Haemophilus influenzae. Ninety percent of the isolates in these groups of bacteria were inhibited by less than 1 mg/l, 2 mg/l, 8 mg/l, 32 mg/l, 0.06 mg/l and 0.25 mg/l of norfloxacin, respectively. Although norfloxacin inhibited most streptococci and Ureaplasma at a concentration of 8 mg/l or less, penicillin G proved to be the most active against Streptococcus pygenes and Streptococcus pneumoniae; trimethoprim was the most active against Streptococcus faecalis, and tetracycline the most active against Ureaplasma.

Product distributions and isotopic selectivities in ir multiphoton dissociation of pentafluoroiodoethane

Infrared multiphoton dissociation of pentafluoroiodoethane leads to a complex array of reaction products. For photolysis in the v4 band the reaction mechanism involves C2F5—I bond cleavage followed by thermal dissociation of C2F5 radicals. For irradiation within the v3 band at high fluence, efficient secondary photolysis of C2F5 radicals is postulated. At lower fluences the dissociation is isotopically selective leading to C4F10 enriched in carbon-13.