Hydraulic pouches of canine latissimus dorsi. Potential for left ventricular assistance

We have studied the fatigue rates of hydraulic pouches constructed in the form of a multilayered conical spiral using the latissimus dorsi muscle of 17 beagles. The roles that electrical muscle conditioning and early interruption of collateral blood supply have in the prevention of pouch fatigue were evaluated. The length of time that a pouch could generate flow in a hydraulic test system was measured; afterload was set at 80 mm Hg and preload 24 mm Hg. Pouches (N = 3) fashioned from muscles subject to neither electrical conditioning nor a vascular delay generated an initial flow of 990 +/- 346 ml/min, but could sustain flow for only 2.3, 3.8 and 3.6 minutes. Pouches (N = 5) constructed with electrically unconditioned muscles after a vascular delay (median 3 weeks) demonstrated a variable improvement in fatigue rates (initial flow 826 +/- 265 ml/min; time to no forward flow, 2.5, 7.5, 7.5, 10, and 200 minutes). Four of six pouches that received the benefit of long-term electrical muscle conditioning and a vascular delay (N = 6) were able to generate flow for a 4 hour period, at which time the experiment was terminated (initial flow 478 +/- 204 ml/min; final flow 195 +/- 157 ml/min). After the 4 hour fatigue test was completed, one electrically conditioned pouch was placed in series with the heart and served as a counterpulsator. The initial volume of blood pumped by the muscle pouch was 262 ml/min or 13.8% of cardiac output. After the pouch had contracted at a rate of approximately 45 beats/min for 1 hour, the volume of blood pumped was 178 ml/min, or 11% of cardiac output. In three other animals a pouch was fashioned and then left in situ for a 1 to 3 week period before hydraulic testing. These pouches generated significant initial flows (390 +/- 60 ml/min), which demonstrates the feasibility of further study of permanent pouches. These results suggest that permanent electrical muscle conditioning and perhaps a vascular collateral delay might permit an auxiliary skeletal muscle-powered ventricle to assume a portion of left ventricular function.     

Fibre type characteristics of the lumbar paraspinal muscles in normal healthy subjects and in patients with low back pain

A knowledge of the alteration in the fibre type profile of paraspinal muscle associated with low back pain is essential for the design of successful rehabilitation programmes. In attempting to compare the muscles of patients with low back pain with those of controls, few previous studies have considered factors such as gender, age, and size of the subjects, each of which can potentially confound interpretation of the results. We obtained samples of lumbar paraspinal muscle during spinal surgery from 21 patients with low back pain and, using the percutaneous biopsy technique, from 21 control volunteers matched for gender, age, and body mass. The samples were subject to routine histochemicsl typcal analysis to determine characteristics of muscle fibre type. Compared with controls, the muscle of the patients had a significantly higher proportion of type-IIB (fast-twitch glycolytic) fibres than type- I (slow oxidatve) fibres. The mean size of a given fibre type did not differ between the patients and the controls. Consequently, the relative area of the muscle iccupied by type-IIB fibres was higher and that by type-I fibres Was lower in the patients. The patients had a greater number of muscle samples with more than 1% type-IIC fibres, and abnormalities that could be described as pathological were more marked in the patients than in the controls. In conclusion, the paraspinal muscles of patients who have low back pain display a more glycolytic (faster) profile; this can be expected to render them less resistant to fatigue.     

Clinical audit in intensive care - the meath intensive care audit

Audit is now recognised as being an essential component of clinical practice. We report on the first year of the Meath Intensive Care Audit (MICA). This audit was instituted to investigate the activity of the unit, to assess the feasibility of continuous audit in our ICU and to provide data for future development of ICU facilities. Two hundred and fifty four patients were admitted between July 1st 1990 and June 30th 1991. The mean age at admission was 58 years and the mean length of stay 5.2 days. The mean APACHE II score was 16. Thirty four patients (13.4%) died in the ICU and 17 patients died in hospital following discharge from the unit bringing the hospital mortality rate to 20%. The audit proved feasible to implement and data collection is now accepted as a routine part of our ICU work.     

A rationalised virological electron microscope specimen testing policy. PHLS North West Viral Gastroenteritis and Electron Microscopy Subcommittee

The aim of this project was to produce guidance for a rationalised virological electron microscopy specimen testing policy for PHLS North West, to facilitate centralisation of a groupwide diagnostic electron microscopy service on a single site. Careful specimen selection to limit numbers and the groupwide use of commercially available enzyme immunoassays has allowed PHLS North West to reduce the number of specimens prepared for electron microscopy. The rationalised virological electron microscopy specimen testing policy has enabled a diagnostic electron microscopy service to be provided from a single site with a manageable workload. Implementation of this specimen testing policy by PHLS North West has been successful and may be applicable to other laboratories (or groups of laboratories) to maximise the use of expensive electron microscopy facilities.     

Personal risk factors for first-time low back pain

STUDY DESIGN: A prospective study of personal risk factors for first-time low back pain. OBJECTIVES: To construct and validate a multivariate model to predict low back pain. SUMMARY OF BACKGROUND DATA: Various physical and psychological factors have been reported to increase the risk of low back pain, but conflicting results may be attributable to inaccurate "clinical" measures and to poorly validated statistical models. METHODS: A total of 403 health care workers aged 18-40 years volunteered for the study. None had any history of "serious" back pain requiring medical attention or time off work. The volunteers completed the following questionnaires: the modified somatic perception questionnaire, the Zung depression scale, and the Health Locus of Control. Anthropometric factors were quantified using standard techniques. The 3Space Isotrak device (Polhemus, VT) was used to measure lumbar curvature and hip and lumbar spine mobility. Leg and back strength and back muscle fatiguability were measured in functional postures. Postal follow-up questionnaires, sent after 6, 12, 18, 24, 30, and 36 months, inquired about back pain, and multivariate logistic regression was used to identify risk factors at each follow-up. RESULTS: The response rate fell from 99% at 12 months to 90% at 36 months, at which time 90 volunteers reported "serious" back pain and 266 reported "any" back pain. The following were consistent predictors of serious back pain: reduced range of lumbar lateral bending, a long back, reduced lumbar lordosis, increased psychological distress, and previous nonserious low back pain. Only the latter three were consistent predictors of "any" back pain. Physical factors had the most influence in a sub-population of volunteers who were new to the job. CONCLUSIONS: Personal risk factors explained up to 12% of first-time low back pain.     

A prospective study of the correlation between genital pathogens and morbidity following diathermy loop excision of the transformation zone.

A prospective study of 48 women was carried out to estimate the incidence of common genital pathogens in women referred to colposcopy clinic requiring diathermy loop excision and to compare patient morbidity in the subgroups with and without genital pathogens. Of the 43 women included in the analysis, genital pathogens were present in 24 cases (56%) and absent in 19 (44%) of the 24 positive cases, 19 (79%) women had pathogen(s) on the cervical swab, 24 (100%) had pathogen(s) on the high vaginal swab and 15 (63%) had both a positive cervical and high vaginal swab (HVS). The most frequently isolated groups of organisms were mixed anaerobes, alone (four HVS and four cervical) or in combination with Gardnerella vaginalis (four HVS and three cervical) or coliforms (two HVS and two cervical). The mean duration of bleeding and vaginal discharge in the two study groups was not statistically significant (t value 1.97, P 0.05; and t value 0.48, P 0.5, respectively). However, the mean duration of bleeding graded by the patient as being moderate to severe was significantly different in the two groups (t value 3.18 P 0.01). Fifty-six per cent of the women in the study had confirmed genital pathogens, predominantly anaerobes, and the prolonged moderate-to-severe bleeding in this group suggests a potential role for prophylactic bacteriocides, although the study size was unable to implicate a single pathogen.     

Psychiatric Aftercare and Suicide Risk: A Case-control Study Using Blind Rating

Blindly abstracted records of last episode of care together with aftercare records of 39 psychiatric patient suicides and their matched controls were rated blind for suicidal talk during aftercare, reduction of aftercare at last appointment and high-low suicide risk. Neither suicidal talk nor reduction of aftercare was confirmed as a predictor of suicide, although trends in the predicted directions were observed. Blind estimates of high-low risk correctly identified a significant minority (40%) of suicides but at the cost of misclassifying 60% as controls. Evidence is still lacking that clinicians blind to case identity may, from records, reliably distinguish a majority of suicides from their matched controls. Some implications for practice and research are discussed.     

Osteomyelitis of the Patella Caused by Legionella anisa

A 51-year-old man with a history of stage IV angioimmunoblastic T-cell lymphoma was diagnosed with osteomyelitis of the patella. Legionella anisa was identified by 16S rRNA gene sequencing and culture. The patient had pneumonia 2 months prior to this osteomyelitis episode. L. anisa was retrospectively detected in his lung tissue by 16S rRNA gene sequencing and was considered the source of the L. anisa that caused his patella osteomyelitis.