Sex related difference in postoperative pain and opioid use following posterior spinal fusion for adolescent idiopathic scoliosis

PURPOSE

This project aims to evaluate the relationship between biological sex and postoperative pain and in patients receiving posterior spinal fusion for adolescent idiopathic scoliosis.

METHODS

This is a retrospective study of patients (n=137) aged 10-17 receiving posterior spinal fusion for adolescent idiopathic scoliosis between 01/2018 and 09/2022. Each patient received surgery by the same pediatric orthopedic surgeon with identical postoperative pain management regimen at a children's hospital or a tertiary referral center with a pediatric spine program.

RESULTS

There were no significant differences in any background characteristics between the male and female patients, including age, BMI, number of levels fused, preoperative degree of scoliosis, and length of surgery and anesthesia (p>0.05). There were no differences in amount given of any intraoperative medications, nor in amount of postoperative scheduled analgesics (p>0.05). Female patients demonstrated higher average pain scores on Visual Analogue Scale evaluations during the first 24 hours postoperatively (5.0 vs 3.6, p<0.0001), 24-48 hours postoperatively (4.9 vs 4.0, p=0.03), and at the first physical therapy evaluation (5.3 vs 3.8, p<0.001). These patients received significantly greater amounts of morphine milligram equivalents in the first 24 hours postoperatively (42.2 vs 31.5, p=0.01) and for the hospitalization in total (63.8 vs 51.3, p=0.048). There was no difference in hours until hospital discharge (44.3 vs 42.6, p=0.62) nor until first ambulation (20.1 vs 21.3, p=0.24) between the female and male patients.

CONCLUSION

The influence of biopsychosocial factors on postoperative pain in adolescents is complex. This study adds to the existing pool of literature suggesting differences in pain perception between adolescent female and male patients. Female patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis may benefit from increased preoperative counseling and more aggressive intra- and postoperative pain management regimens.

Evidence for a Multimodal Pain Management Regimen in Reduction of Postoperative Opioid Use in Pediatric Patients Receiving Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

This project aims to evaluate the relationship between increased use of intraoperative nonopioid analgesics, muscle relaxers, and anesthetics and postoperative outcomes, including opioid utilization, time until ambulation, and hospital length of stay.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis (AIS) is a structural deformity of the spine that occurs in otherwise healthy adolescents, occurring with a frequency of 1% to 3%. Up to 60% of patients receiving spinal surgeries, particularly posterior spinal fusion (PSF), experience at least 1 day of moderate-to-severe pain after surgery.

PATIENTS AND METHODS

This is a retrospective chart review of pediatric patients aged 10 to 17 having received PSF with >5 levels fused for AIS at a dedicated children's hospital and a regional tertiary referral center with a dedicated pediatric spine program between January 2018 and September 2022. A linear regression model was used to evaluate the influence of baseline characteristics and intraoperative medications on the total amount of postoperative morphine milligram equivalents received.

RESULTS

There were no significant differences in the background characteristics of the two patient populations. Patients receiving PSF at the tertiary referral center received equivalent or greater amounts of all nonopioid pain medications and demonstrated decreased time until ambulation (19.3 vs . 22.3 h), postoperative opioid use (56.1 vs . 70.1 MME), and postoperative hospital length of stay (35.9 vs . 58.3 h). Hospital location was not individually associated with a difference in postoperative opioid use. There was not a significant difference in postoperative pain ratings. When accounting for all other variables, liposomal bupivacaine had the greatest contribution to the decrease in postoperative opioid use.

CONCLUSION

Patients receiving greater amounts of nonopioid intraoperative medications utilized 20% fewer postoperative morphine milligram equivalents, were discharged 22.3 hours earlier and had earlier recorded evidence of mobility. Postoperatively, nonopioid analgesics were as effective as opioids in the reduction of subjective pain ratings. This study further demonstrates the efficacy of multimodal pain management regimens in pediatric patients receiving PSF for AIS.

Thermal requirements for growth, survival and aerobic performance of weatherfish larvae Misgurnus fossilis

Thermal requirements of larval weatherfish Misgurnus fossilis were investigated in terms of growth, survival and aerobic performance. Growth and survival of M. fossilis larvae acclimated to five temperatures (11, 15, 19, 23 and 27° C) were measured over 25 days. In the upper temperature treatments (19, 23 and 27° C), survival of larvae was stable throughout the entire rearing period (>75%), whereas 11 and 15° C resulted in severe declines in survival (to <10%). Growth of larvae (expressed as dry mass and total length) was highest at 19 and 23° C, but significantly decreased at 27° C. Routine metabolic rate of 3 days post-hatch larvae was estimated as oxygen consumption rate (ṀO₂ ) during acute exposure (30 min to 1 h) to seven temperatures (11, 15, 19, 23, 27, 31 and 35° C). Larval oxygen uptake increased with each consecutive temperature step from 11 to 27° C, until a plateau was reached at temperatures >27° C. All larvae of the 35° C regime, however, died within the ṀO₂ measurement period. M. fossilis larvae show greater than expected tolerance of high temperatures. On the other hand, low temperatures that are within the range of likely habitat conditions are critical because they might lead to high mortality rates when larvae are exposed over periods >10 days. These findings help to improve rearing conditions and to identify suitable waters for stocking and thus support the management of re-introduction activities for endangered M. fossilis.

Prophylactic antibiotics in elective hip and knee arthroplasty: an analysis of organisms reported to cause infections and National survey of clinical practice

Objectives

We wanted to investigate regional variations in the organisms reported to be causing peri-prosthetic infections and to report on prophylaxis regimens currently in use across England.

Methods

Analysis of data routinely collected by Public Health England’s (PHE) national surgical site infection database on elective primary hip and knee arthroplasty procedures between April 2010 and March 2013 to investigate regional variations in causative organisms. A separate national survey of 145 hospital Trusts (groups of hospitals under local management) in England routinely performing primary hip and/or knee arthroplasty was carried out by standard email questionnaire.

Results

Analysis of 189 858 elective primary hip and knee arthroplasty procedures and 1116 surgical site infections found statistically significant variations for some causative organism between regions. There was a 100% response rate to the prophylaxis questionnaire that showed substantial variation between individual trust guidelines. A number of regimens currently in use are inconsistent with the best available evidence.

Conclusions

The approach towards antibiotic prophylaxis in elective arthroplasty nationwide reveals substantial variation without clear justification. Only seven causative organisms are responsible for 89% of infections affecting primary hip and knee arthroplasty, which cannot justify such widespread variation between prophylactic antibiotic policies.

Cite this article: Bone Joint Res 2015;4:181–189.

Effects of fluoroquinolone restriction (from 2007 to 2012) on resistance in Enterobacteriaceae: interrupted time-series analysis

BACKGROUND

Antibiotic stewardship is a key component in the effort to reduce healthcare-associated infections.

AIM

To describe the implementation and analyse the impact of fluoroquinolone restriction on resistance in Enterobacteriaceae, focusing on urinary isolates of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, which were historically almost universally resistant to fluoroquinolones.

METHODS

ESBL-producing E. coli hospital and community isolates, obtained between April 2009 and March 2012 from consecutive non-duplicate urine samples, were included in an interrupted time-series analysis based on a Poisson distribution model. Periods before and after fluoroquinolone restriction were compared. The trend in fluoroquinolone resistance in all urinary isolates of Enterobacteriaceae (N ≈ 20,000 per year) and blood culture isolates of E. coli (N ≈ 350) between 2009 and 2013 were also analysed.

FINDINGS

A large decline in the percentage of ciprofloxacin-resistant ESBL-producing urinary E. coli isolates was observed in both hospital (risk ratio: 0.473; 95% confidence interval: 0.315-0.712) and community settings (0.098; 0.062-0.157). The decline was also marked in all urinary isolates of Enterobacteriaceae and E. coli isolates from blood cultures.

CONCLUSION

We conclude that reducing fluoroquinolone usage to a level of ≤2 defined daily doses per 100 occupied bed-days in hospital sufficiently removed selection pressure to allow resistant Enterobacteriaceae – specifically, the UK endemic strains of ESBL-producing E. coli – to revert back to fluoroquinolone susceptibility within a short span of four months. This was accompanied with a concomitant reduction in overall ESBL burden.

Changing antibiotic prophylaxis for primary joint arthroplasty affects postoperative complication rates and bacterial spectrum

BACKGROUND

The reduction of Clostridium difficile associated diarrhoea (CDAD) is a national priority. As part of the C. difficile improvement plan in our Trust, antibiotic prophylaxis for primary arthroplasty was changed from cefuroxime to gentamicin. Gentamicin was chosen following a review of the sensitivity profiles of all the organisms isolated from infected primary arthoplasties.

METHODS

From January 2002 to September 2007, 6094 patients (Group 1) undergoing primary hip and knee arthroplasty received three doses of Cefuroxime as prophylaxis; while from October 2007 to February 2009, 2101 patients (Group 2) received single dose Gentamicin (4.5 mg/kg). We studied the rate of CDAD as well as several other postoperative complications, including rate of return to theatre (RTT), before and after the change.

FINDINGS

There was an insignificant fall in CDAD from 0.18% to 0% (p=0.08) in Group 2, however there was a statistically significant increase in pneumonia (0.67-1.33%, p<0.01), acute renal failure (ARF) requiring HDU admission (0.07-0.33%, p<0.01) and RTT (1.08-1.95%, p<0.01) in this group. RTT for proven infection increased from 0.66% to 1.52% (p<0.01).

CONCLUSIONS

We conclude that Gentamicin 4.5 mg/kg alone should not be used as prophylaxis for primary joint arthroplasty as it does not reduce CDAD significantly but increases the risk of other postoperative complications. We have changed our prophylaxis to low dose gentamicin (3 mg/kg) combined with Teicoplanin 400 mg given once.

Avoiding Free Nipple Grafting With the Inferior Pedicle Technique

In cases of severe macromastia, the free nipple graft technique has been the traditional alternative to pedicle transposition. Distress over nipple survival in large reduction mammaplasty and long pedicle transposition is largely responsible for this.A retrospective investigation of the records of 142 reduction mammaplasty patients was carried out to determine whether nipple survival or overall complication rates were significantly different in patients undergoing larger (>1500 g per side) as compared with smaller reductions (< 1500 g per side). The 2 patient groups were compared with respect to mild or severe complications. Data were analyzed using Fisher exact test and 2-sample t tests. A P value of < 0.05 was considered statistically significant. No patient in either group had total nipple loss. There were no statistically significant differences in major or minor complications between the 2 groups. In our experience, the inferior pedicle, Wise pattern reduction is a reliable and predictable method of reduction, appropriate for all breast sizes and pedicle lengths.

Vascular endothelial growth factor (VEGF) expression and the effect of exogenous VEGF on survival of a random flap in the rat

The induction of endogenous vascular endothelial growth factor (VEGF) production in the skin flap with ischemic injury and the effect of exogenous VEGF on survival of the ischemic skin flap were studied in rats. A dorsal flap model (3x10 cm(2)) was used in this study. In Part I, biopsies were taken from the flap at 2.5, 5.5, and 8.5 cm distances from the distal edge at 0, 6, 12, and 24 h after the flaps were sutured. Malonyldialdehyde (MDA) and VEGF(165) protein level were measured. In Part II, exogenous VEGF (1 microg/ml) was injected subdermally into the flaps in 14 rats before the flaps were replaced. Flaps that received a saline injection were used as the controls. The skin paddle survival was measured on postoperative day five. The results showed that the MDA level in the distal part of the flap significantly increased at 24 h postoperatively when compared to MDA in other parts of the flap. However, VEGF levels in the distal part of the flap significantly decreased when compared to the middle part of the flap. Subdermal injection of exogenous VEGF to the distal area of the flap could significantly improve survival of the distal flap (89% of total skin paddle) when compared to the control, which had a 64% mean percent survival. We conclude that production of endogenous VEGF protein is significantly increased in the skin flap with mild ischemia, but decreased in the flap with severe ischemia. Administration of exogenous VEGF could significantly enhance survival of ischemic flaps.

Serum antibody titers to Bacteroides forsythus in elderly subjects with gingivitis or periodontitis

BACKGROUND

The risks for periodontal disease appear to increase with age.

STUDY PURPOSE

To determine associations between clinical findings, the presence of specific bacteria in periodontal pockets, and serum antibody titers. 10 older subjects (mean age=73.0 years SD+/-4.9) with confirmed gingivitis only (gingivitis group) and 10 subjects with periodontitis (mean age: 76.1 years, SD+/-10.4) (periodontitis group) were studied.

RESULTS

The mean group differences for probing depth and clinical attachment levels were 4.1 mm and 5.6 mm, respectively, and were significantly different (p<0.001). Both groups had high plaque scores (>60% surfaces with plaque). DNA probes demonstrated that B. forsythus was present in 8/10 samples from the periodontitis group and in 7/10 samples from the gingivitis group. The B. forsythus isolates studied were found in four of the subjects with periodontitis and from 2 of the subjects with gingivitis. Serum antibody titers to 6 ribotypes of B. forsythus were studied. Western blots, gradient gels, and pulsed field gel electrophoresis concurrently demonstrated that the B. forsythus isolates were genotypically, and phenotypically unique for each subject. Antibody titers to two selected B. forsythus isolates were significantly higher in the periodontitis group (p<0.01, Mann-Whitney test). The study confirmed that antibody serum titers to the six different ribotypes of B. forsythus varied greatly between older individuals with gingivitis or periodontitis. Not all strains of B. forsythus elicited higher titers in periodontitis affected subjects.

CONCLUSIONS

The results of the present study suggest genotype variation of B. forsythus that is unique to the individual and that serotype variation can be expected. It is possible that B. forsythus under specific host conditions can modulate surface antigen factors to evade the host immune response.

Clinical and microbiological findings in elderly subjects with gingivitis or periodontitis

The objective of the present study was to study the supra- and subgingival microflora by culture and cDNA probe methods in 20 elderly subjects who were between 62 and 93 years of age. 10 of them had gingivitis only, and 10 had periodontitis. B. forsythus (BF), P. gingivalis (PG), P. intermedia (PI), P. nigrescens (PN), A. actinomycetemcomitans (AA), T. denticola (TD), and pathogen-related oral spirochetes (PROS) were studied. Oral hygiene was similar and poor in both groups. The mean probing depth at sample sites was 6.7 mm (S.D+/-1.3) in the periodontitis group and 2.2 mm (S.D.+/-1.5) in the gingivitis group (F=17.75, p<0.001). Mean clinical attachment levels (CAL) were 4.3 mm (S.D.+/-2.0) and 1.7 mm (S.D.+/-0.9) respectively (p<0.001). Total viable counts >1.0x10(5) in supra-gingival plaque samples were found in all periodontitis and in eight gingivitis subjects. 70x more black-pigmented organisms were found in supra-gingival and 185 times more in sub-gingival plaque from the periodontitis group (p<0.01). Culture data showed P. nigresecens in 10% periodontitis and 50% gingivitis subjects (p<0.03). In supra-gingival samples by the Affirm DP test, BF was present in 50% periodontitis and 60% gingivitis while culture data were negative for all subjects. PG was found in 30% periodontitis and 50% gingivitis subjects with TD in 70% periodontitis and in 30% gingivitis subjects. In the sub-gingival plaque samples 80% periodontitis and 70% gingivitis subjects had >1x10(5) anaerobes. The total count of black-pigmented organisms was significantly greater in the periodontitis elders (p<0.001). cDNA probes by the Affirm DP test identified subgingival presence of BF (80%) PG (80%), PI (80%), AA (0%), TD (50%) in periodontitis subjects with BF (70%), PG (40%), PI (30%) and TD (20%) in gingivitis subjects. PROS were found in (80%) samples from periodontitis and in (60%) of gingivitis elderly. Only the quantities of PI (r=0.48, p<0.01) and TD (r=0.37, p<0.01) were associated with the disease definition. The smoking habit in the periodontitis group was significantly higher (p<0.01). A history of smoking may contribute significantly to periodontitis in the presence of pathogens.

Preliminary evaluation of a sensory and psychomotor functional test battery for carpal tunnel syndrome: Part 2--Industrial subjects

This study evaluated the Wisconsin functional sensory and psychomotor test battery for carpal tunnel syndrome (CTS). Subjects were 27 employees recruited from a food processing plant. Both hands of all subjects were examined and categorized by presence or absence of symptoms and nerve conduction study (NCS) findings (Symptom-/NCS-, Symptom+/NCS-, Symptom-/NCS+, and Symptom+/NCS+). Symptom-/NCS- category hands had significantly better performance (15-60%) for most of the functional test battery variables than Symptom+/NCS+ category hands. A significant gap detection threshold difference (32%) was observed between NCS+ and NCS- hands regardless of symptoms, with NCS- having impaired performance. No significant effect of CTS symptoms on performance was observed. Stepwise discriminant analysis was used to select the best variables to differentiate between groups. The ratio of the change in pinch rate with respect to required pinch force differentiated NCS+ from NCS- hands, with a sensitivity of 0.71 and a specificity of 0.68. The same variable had a sensitivity of 0.74 and specificity of 0.83 for distinguishing Symptom-/NCS- hands from all other categories. Pinch rate had a sensitivity of 0.82 and a specificity of 0.81 for separating Symptom+/NCS+ hands from all other categories. Use of both gap detection threshold and the ratio of the change in pinch rate with respect to required pinch force could best differentiate Symptom+/NCS+ from Symptom-/NCS- cases for a sensitivity of 0.91 and specificity of 0.87. Outcomes could not be generalized to a specific work population but demonstrate that the non-invasive test battery may be useful for providing objective measures of deficits associated with CTS symptoms and electrophysiological parameters.

Purification of (His)6EcoRV [recombinant restriction endonuclease EcoRV fused to a (His)6 affinity domain] by metal-chelate affinity chromatography

The chromatographic purification of (His)6EcoRV, a fusion protein consisting of a hexahistidine affinity domain and restriction endonuclease EcoRV produced from recombinant Escherichia coli, led to high product concentrations (> or = 1 mg/ml) in the preparative mode. Increasing the amount of applied crude cell homogenate caused competition with host-specific proteins was achieved by pre-adsorption on to a DEAE anion-exchange sorbent. This, in combination with 0.5-1 M NaCl in the adsorption buffer, assured a purity > 95% and a total protein recovery of approximately 34% in the preparative mode. Contamination of the product with about 2 mol of Ni(11)/mol of (His)6EcoRV was found due to metal-ion transfer to the N-terminal high-affinity binding site at (His)6. Tris(carboxymethyl)ethylenediamine (TED)-Sepharose was employed as an Ni(11) adsorber. One passage of Ni(11)-contaminated protein solutions through the TED-Sepharose column resulted in a decrease in the Ni(11) content in the (His)6EcoRV fractions below the detection limit (approximately 0.02 mg/l) of the atomic-adsorption spectrophotometer.

Comparison of N-terminal affinity fusion domains: effect on expression level and product heterogeneity of recombinant restriction endonuclease EcoRV

The influence of different N-terminal affinity fusion domains on the product heterogeneity of recombinant proteins expressed in Escherichia coli was investigated. N-Terminal extended forms of the restriction endonuclease EcoRV with either glutathione-S-transferase [GST], histidine hexapeptide [(His)6], or a combination of GST and (His)6 [GST-(His)6] were compared to native EcoRV with respect to expression level, susceptibility to inclusion body formation and protein fragmentation. Fingerprinting of product heterogeneity was done by using two-dimensional (2-D) non-equilibrium pH-gradient electrophoresis with subsequent immunoblotting. Fusion proteins containing GST were poorly expressed compared to native EcoRV. In addition, GST fusion proteins were highly susceptible to in-vivo aggregation and fragmentation and displayed more heterogeneity on 2-D immunoblots. However, the sole presence of oligohistidine at the N-terminus of EcoRV proved to be advantageous. Fragmentation of (His)6-EcoRV was not observed and 2-D immunoblots did not show heterogeneous forms of the recombinant protein. In addition, fusion of the histidine-hexapeptide to the N-terminus of native EcoRV increased the expression level of the recombinant protein twofold compared to native EcoRV. Inclusion body formation of the (His)6-EcoRV fusion protein was intensive when cells were grown at 37 degrees C but not at 30 degrees C. The advantage of oligohistidine fusion to EcoRV was finally demonstrated by purifying soluble (His)6-EcoRV in a single-step procedure from crude cell lysates using immobilized metal chelate affinity chromatography.

Reduced Adsorption And Separation Of Blended Surfactants On Sand And Clay

Abstract

Recent successful field trials of foam floods using surfactants containing disulfonated alkyldiphenyloxides have stimulated interest in the use of these surfactant in other EOR projects. Adsorption and separation of such surfactants is still a concern among some members of the petroleum industry. This paper will briefly discuss some of the advantages of using blended surfactants, notably enhanced mobility control and improved hardness tolerance. The main emphasis will be on the adsorption and separation of these surfactants when in contact with sand and clay. It has been found that adsorption of surfactants from blends is significantly lower than from "pure" surfactants and that separation of the blends is much less of a concern than is commonly believed. Adsorption and separation studies were done using water containing different concentrations of inorganic salts, and sand and sand/montmorillonite adsorbents.

Introduction

Recent successes in Alberta oil fields, notably by Signalta Resources of Calgary and Dome/Amoco, also of Calgary, have stimulated interest in the use of blended surfactants for enhanced oil recovery by foam flood. There are several reasons for considering blended surfactants for EOR application. These include enhanced mobility control and improved solubility. Experiments carried out at the Petroleum Recovery Institute (PRI) in Calgary using high pressure core tests, and in the Oil and Gas Lab at Dow using low pressure equipment have indicated a synergistic effect in mobility control as a result of blending surfactants. These results were presented at the 7th International Symposium on Surfactants in Solution(1), held in Ottawa in October 1988.

Alpha olefin sulfonates (AOS's) are relatively inexpensive and available, produce good foams and are thermally stable, all important considerations for a good foam flooding surfactant. The biggest impediment to the use of AOS's in enhanced oil recovery is the very poor solubility of these surfactants in water containing divalent captions such as calcium and magnesium. Many reservoirs contain enough of these metal ions to preclude the use of pure AOS. This obstacle can be overcome by blending AOS with another type of surfactant.

There are some lingering concerns about the wisdom of using blends, primarily because of anticipated separation of the components of the blends as a result of preferential adsorption.

Results

Solubility

One of the products which has been used in the field is a blend of AOS and DOWFAX* disulfonated alklydiphenyloxide (DPOS) produced by Dow Chemical. The structure of this disulfonate surfactant is shown in Figure l. Calcium and magnesium salts of these disulfonates are water soluble, and remain so even in very concentrated solutions of inorganic salts of these metals.

The solubility of AOS in sodium chloride solutions is increased by the presence of the disulfonated diphenyloxide. The first set of results (Fig. 2) shows the effects of temperature and blend composition on the solubility of the surfactant in sodium chloride solution. The concentration of AOS was held constant at 1.0 g AOS (- 50% active) in 100 mL of water. Varying amounts of the diphenyloxide surfactant (- 50% active) were added to the AOS solutions to give AOS/DPOS weight/weight ratios as shown.

Myocardial gated tomoscintigraphy with 99Tcm-methoxy-isobutyl-isonitrile (MIBI): regional and temporal activity curve analysis

Myocardial gated tomoscintigraphy with hexakis-(2 methoxy-isobutyl-isonitrile) labelled with 99Tcm, is more suitable to resolve precisely the size of myocardial infarct than nongated 201Tl tomoscintigraphy. Gated tomography gives short axis slices at eight points in the cardiac cycle. A quantitative method to analyse heart wall activity and its motion is proposed. In two groups of patients, one with inferior infarct and the other with anterior infarct, the time-activity curves show a maximum in systole for healthy regions and a flattened curve in akinetic regions. Gated tomoscintigraphy assesses more accurately the size of the injured regions because there is no averaging between systolic and diastolic activity as in 201Tl tomoscintigraphy. This method should permit a better follow-up of patients with myocardial infarct.

Significance of spontaneous obstruction of high degree coronary artery stenoses between diagnostic angiography and later percutaneous transluminal coronary angioplasty

Among 265 patients with severe coronary artery stenoses amenable to percutaneous transluminal coronary angioplasty, 13 (5%) developed new total coronary occlusion of the vessel to be dilated during the period between diagnostic coronary angiography and repeat coronary angiography at the time of the operation. Time from diagnostic to "therapeutic" angiography (76 +/- 74 vs 31 +/- 31 days, p less than 0.0001), degree of coronary stenosis on diagnostic angiography (85 +/- 7 vs 80 +/- 8%, p less than 0.05) and impaired coronary flow distal to the narrowing (Thrombolysis in Myocardial Infarction grade 2: 38 vs 10%, p less than 0.01) were the only variables related to the occurrence of spontaneous coronary occlusion. The clinical course of the patients who developed new total coronary occlusion was remarkably favorable. Twelve of the 13 patients had unchanged or improved anginal symptoms. The electrocardiogram at rest remained unchanged in 11 patients and there was no transmural myocardial infarction. Eight patients had 2 ventriculograms and the mean ejection fraction remained unchanged (only 2 patients had greater than 5% decrease in ejection fraction between the 2 examinations). Spontaneous occlusion of high degree coronary artery stenoses is not unusual and is usually well tolerated, presumably due to the development of collateral circulation.

[Prognosis of spontaneous occlusions in tight coronary stenosis]

Eighteen out of 408 patients assigned to coronary angioplasty rapidly developed complete obstruction of the vessel to be dilated. The results of a retrospective study of clinical, biochemical, angiographic and/or angio-scintigraphic events in these 18 patients are reported. The interval between the two coronary arteriographies was 67 +/- 66 days. Angina was initially unstable in 9 patients and stable in 6; 3 patients were asymptomatic. Coronary lesions followed the usual distribution pattern: the left anterior descending artery was involved in 11 cases, the circumflex artery in 4 cases and the right coronary artery in 3 cases. Overall, the degree of stenosis was high (86 +/- 7%); Following obstruction the course of the disease was favourable in 11 patients (61%), with complete remission of all symptoms in 5. Six patients remained with unstable angina. Apart from one case of sudden death, none of the patients developed myocardial infarction, as shown by the absence of significant biochemical, electrical and angiographic changes. The importance of pre-existing or newly developed collateral circulation as a good prognosis factor is highlighted.

Non-invasive diagnosis of pulmonary hypertension in chronic obstructive pulmonary disease. Comparison of ECG, radiological measurements, echocardiography and myocardial scintigraphy

The respective value of four non-invasive methods for the diagnosis of pulmonary arterial hypertension (PAH) was investigated in 63 COPD patients, using right heart catheterization as the reference method: 22 patients had no resting PAH (pulmonary artery mean pressure (PAP) less than or equal to 20 mmHg); 26 patients had mild PAH (PAP = 21-30 mmHg); and 15 patients had moderate to severe PAH (PAP greater than 30 mmHg). The specificity of ECG was 86% and the sensitivity 51% (only 38% in mild PAH). The specificity of radiological measurements was 63% and the sensitivity 46% (38% in mild PAH). Echocardiography (echo) had the best results with a specificity of 75% and a sensitivity of 78% (73% in mild PAH), but reliable echo measurements were available in only 52 out of 63 patients. Myocardial scintigraphy had a specificity of 68% and a sensitivity of 66% (58% in mild PAH). A stepwise regression analysis (including one echo, one ECG, one radiological and one functional variable) explained only 43% of the variance of PAP (multiple r = 0.66). These results suggest that no individual method is sufficiently reliable for predicting the presence of PAH, and particularly mild PAH, but the combination of echo + myocardial scintigraphy allows the prediction of PAH with a good probability. The precise level of PAH cannot be estimated, even when using multiple regression equations.

Peripheral nerve carbonic anhydrase activity and chronic acetazolamide treatment of rats

Examination of cranial nerves shows that the sensory infraorbital branch of the trigeminal nerve contains many carbonic anhydrase-reactive axons whereas axons of the motor facial nerve are non-reactive. This motor/sensory axon staining difference holds for both cranial and spinal nerves. Chronic treatment with acetazolamide produced no apparent changes in carbonic anhydrase histochemical activity or the structure of peripheral nerve fibers.

[Home oxygen therapy of chronic bronchitis patients. Clinical, functional and pulmonary hemodynamic results. Apropos of 17 cases]

Seventeen subjects (16 male, 1 female) with a mean age of 60 +/- 7 years were studied.

INCLUSION CRITERIA

severe chronic bronchitis (mean FEV1 = 960 ml with frank hypoxaemia (PaO2 less than 60 mmHg); past history of right heart failure or electrical signs of right ventricular hypertrophy or pulmonary hypertension (PAP greater than 20 mmHg); oxygen therapy at home for greater than 10/24 hours (most often greater than or equal to 12 hours) for more than a year; interval of more than 6 months between the first haemodynamic investigation (before the start of O2) and the last, this period being on average 23.9 +/- 18.6 months. From a clinical standpoint, there were 5 deaths occurring 11 to 30 months after the start of O2. Effort dyspnoea was stable or worsened but hospitalisations for cardiorespiratory decompensation were less frequent than before the start of O2. There were no significant changes in arterial blood gases: PaO2 rose from 51.9 +/- 8.1 to 52.5 +/- 7.0 mmHg. PAP improved in 12 cases out of 17, and for the group as a whole the difference was not statistically significant. However in the sub-group where the daily duration of administration was greater than 12/24 hours (n = 7), PAP improved in all the individual cases and fell on average from 26.4 +/- 6.8 to 19.9 +/- 3.4 mmHg (p less than 0.02) whilst in the 10-12 hours sub-group there was no mean change in PAP.(ABSTRACT TRUNCATED AT 250 WORDS)

[Diffuse interstitial pneumopathy related to tungsten carbide, confirmed by bronchoalveolar lavage, and responding to corticotherapy]

The authors report a case of severe diffuse interstitial hard metal lung disease responding to corticosteroid therapy. They point out that the course of this disease may be regressive and emphasise that analysis of broncho-alveolar washings showed no abnormality in the differential cell count. Mineralogical study of the same material confirmed exposure.

Kinetics and mechanisms of the oxidation of ascorbic acid and benzene diols by nickel(III)tetraazamacrocycles in aqueous perchloric acid

The kinetics of reaction of ascorbic acid, hydroquinone, and catechol (H2A) with nickel(III) macrocycles (NiL3+) (L = cyclam, meso-(5,12)-7,7,14,14-Me6-14-ane-1,4,8,11-N4 (tet-a), and rac-(5,14)-7,7,12,12-Me6-14-ane-1,4,8,11-N4 (tet-c):[Formula: see text]have been investigated in aqueous perchloric acid solutions using the stopped-flow technique. The data are consistent with a rate-determining one-electron transfer reactions:[Formula: see text]followed by a rapid oxidation of the radical formed. In the reaction with ascorbic acid, for Ni(cyclam)3+, k1 = 250 M−1 s−1 (25 °C), k4Ka = 680 s−1; Ni(tet-c)3+, k1 = 2.52 × 103 M−1 s−1, k4Ka = 1.06 × 104 s−1; and Ni(tet-a)3+, k1 = 2.85 × 103 M−1 s−1 (21.95 °C), k4Ka = 1.26 × 104 s−1. With catechol, k1 = 6.98 × 102 M−1 s−1, 1.73 × 104 M−1 s−1, and 3.3 × 104 M−1 s−1 respectively in reactions with Ni(cyclam)3+, Ni(tet-c)3+, and Ni(tet-a)3+. With hydroquinone, k1 = 1.09 × 104 M−1s−1 (Ni(cyclam)3+) and 2.49 × 105 M−1 s−1 (20.9 °C) (Ni(tet-c)3+). The reactions are considered to take place via an outer-sphere mechanism and rate constants are discussed in terms of the Marcus cross correlation. Use has been made of predicted rate constants to identify reaction pathways in the hydrogen-ion dependent systems.

Entomophthora thripidum, a new fungal pathogen of Thrips tabaci

Entomophthora thripidum sp. nov. is described and illustrated. The species is pathogenic for Thrips tabaci Lind. (Thysanoptera: Thripidae) and caused epizootics in populations of this species in glasshouses in the Netherlands. Entomophthora thripidum is characterized by spores which are broadly ellipsoidal with a pointed apex and truncate base. Infection is restricted to the abdominal parts of the body and primary spores can be discharged from the living hosts. The secondary spores are similar but smaller than the primary ones. Details about the seasonal history and symptoms of the disease are described. The invalidly published name Empusa weberi Lakon (= Entomophthora weberi (Lakon) Batko) is validated by a Latin diagnosis.

Preparation of subcellular fractions from rat liver: comparison of the Polytron with the Dounce homogenizer

The PolytronR and Dounce homogenizers have been evaluated for preparation of homogenates of rat liver prior to isolation of subcellular fractions by differential centrifugation. Marker enzymes used to evaluate the subcellular fractions included cytochrome oxidase, monoamine oxidase, D-amino acid oxidase, acid phosphatase, glucose-6-phosphatase, ethyl morphine demethylase, and lactate dehydrogenase. No significant difference in the distribution of enzymes (percent recovery or specific activity) was observed between the two methods of homogenization. In addition, there were no significant differences in the ultrastructural appearances and respiratory control ratios of the mitochondrial fractions prepared by the two methods of homogenization.