Advancing nursing in the academic community: adopt an administrator

The role of faculty in nursing schools is unique. Faculty members belong to the community of scholars, as well as the community of practitioners. The authors describe a program to educate key university leaders about the role of nursing faculty. The program achieved its objectives in a timely, cost-effective manner, and could be easily replicated at other universities.

The ventilatory response to carbon dioxide in high risk infants

PURPOSE

To examine the ventilatory response to inspired carbon dioxide in infants considered to be at risk for sudden infant death syndrome or apnea.

DESIGN

Clinical data measurement.

SETTING

Infant apnea evaluation program of a university division of neonatology.

PATIENTS

Fifty nine infants were full term characterized by the following diagnoses; siblings of infants who had died from sudden infant death syndrome (SIDS) (n = 7), apparent life threatening event (ALTE) (n = 24), apnea/cyanosis in the newborn nursery (n = 21), and controls. Sixty-nine infants were preterm and consisted of patients suffering from idiopathic apnea (n = 61), and bronchopulmonary dysplasia (n = 8).

MEASUREMENTS

The ventilatory response to carbon dioxide was measured with a computerized waveform analyzer.

MAIN RESULTS

Among full term infants no significant differences in the ventilatory slope in response to CO2 was seen. The range of mean slope was 19.4 +/- 7.6 in siblings of SIDS and 36 +/- 17 in control infants. Greater number of sibling of SIDS had slopes less than 20 ml/kg/min/mmHg in comparison to control infants. Sibling of SIDS had less increase in minute ventilation and inspiratory flow in response to CO2 administration in comparison to control infants. Preterm infants had similar slopes with a mean of 33 ml/kg/min/mmHg in infants with idiopathic apnea and 28 ml/kg/min/mmHg in infants with bronchopulmonary dysplasia.

CONCLUSIONS

The large intragroup variability in the ventilatory response to inspired CO2, confirming previously reported data, comprises the benefit of this test. Thus, ventilatory response to CO2 administration is not useful in unselected patients at risk of SIDS or apnea.

Knee immobilization inhibits biomechanical maturation of the rabbit medial collateral ligament

In this investigation, the effect of immobilization on the structural biomechanical properties of the immature rabbit medial collateral ligament (MCL) was quantified. The right hindlimbs of ten, three-month-old female New Zealand White rabbits were immobilized. The hindlimbs of the first group (n = 5) were immobilized for one month, until the rabbits were four months of age. The hindlimbs of the second group (n = 5) were immobilized for three months, until the rabbits were six months of age. Left hindlimbs were not surgically treated and served as contralateral controls. Fifteen normal animals were kept in similar cages until they were killed in subgroups at three, four, or six months of age. Biomechanical investigations after the animals were killed included the testing of a number of MCL structural properties, including prefailure and strength tests. Results showed that the maturation of MCL structural properties were inhibited during immobilization with signs of structural degradation becoming more obvious at the longer period of immobilization. Results also demonstrated that the structural mechanical properties of the contralateral MCLs were significantly altered. These results suggest that knee mobility is essential to the normal maturation of MCL mechanical properties and that contralateral MCLs cannot be used as normal controls in this immature rabbit model of immobility.

A randomized and longitudinal study of human menopausal gonadotropin with intrauterine insemination in the treatment of infertility

OBJECTIVE

To study in a randomized and longitudinal manner the efficacy of human menopausal gonadotropin (hMG) superovulation combined with intrauterine insemination (IUI) versus IUI alone in the treatment of various causes of infertility in the presence of normal ovulation.

METHODS

An initially randomized and subsequently longitudinal study of infertile couples was performed at a university-based clinical research center. One hundred nineteen couples with longstanding infertility (average duration 3.7 years) associated with male factor infertility, unexplained infertility, and/or endometriosis were enrolled. All patients were randomized in the initial cycle to treatment with either hMG/IUI or urine LH-timed IUI alone. They were then followed longitudinally as they alternated subsequent cycles between the two modalities. Outcome indices measured were cycle fecundity, pregnancy outcome, and cumulative pregnancy rates evaluated by life-table analysis.

RESULTS

Human menopausal gonadotropin/IUI therapy was consistently more effective than IUI alone in the treatment of endometriosis, male factor infertility, and unexplained infertility, with cycle fecundities ranging from 7.1-19.0% versus 0-6.7%, respectively, during the first seven cycles.

CONCLUSION

Human menopausal gonadotropin/IUI is a more effective therapy for enhancing fertility than is IUI alone for the treatment of endometriosis, male factor infertility, and unexplained infertility.

Blood transfusion does not have an adverse effect on survival after operation for colorectal cancer

The effect of perioperative blood transfusion on cancer progression remains controversial because retrospective clinical studies have produced conflicting results. We have collected data prospectively on 379 patients undergoing curative surgery for colorectal adenocarcinoma and assessed the effect of variables, including blood transfusion, on survival. Univariate and multivariate survival analysis has been carried out. When the end-point for analysis used was death due to recurrent colorectal carcinoma and non-cancer deaths were censored, there was no difference in cancer-specific survival between transfused and non-transfused patients. Survival analysis was also carried out without censoring the non-cancer deaths and clearly demonstrated how the statistical analysis and data interpretation could be distorted by age-related non-cancer deaths. The incidence of recurrence of colorectal carcinoma was not greater in the transfused group than in the non-transfused group. We conclude that blood transfusion should not be withheld in colorectal surgery for fear of worsening the prognosis.

The effects of All-RN and RN-EN staffing on the quality and cost of patient care

This paper presents empirical evidence from a study that compared the quality and costs of patient care provided by two staffing regimes in an acute medical and an acute surgical ward in one hospital. As assessed by patient outcomes, there were few significant differences in either ward in the quality of care provided by all registered nursing staff and staff that was comprised of 80% registered nurses and 20% enrolled nurses. In the acute medical ward the all-registered nursing staff was more expensive per day and per hour for patient care adjusted for patient dependency; in the acute surgical ward the registered-enrolled nurse staff mix was more costly. The study found that nurses in both wards were confronted by continuously high workloads. Registered nurses reported that working with enrolled nurses (who were inexperienced in acute medical and surgical nursing) exacerbated their workload and, to a lesser extent, made their work more stressful. Large scale, long term studies are necessary to clarify the issues of cost effectiveness of RN-EN mix and workloads.

Perinatal estradiol benzoate administration affects control of ventilation in adult male rats

One injection of estradiol benzoate (EB) (100 micrograms) or vehicle was administered to male rat pups 5 days after birth. Two months later ventilation, ventilatory responses to 7% carbon dioxide, and to 580 mg/kg aspartic acid (an agent used as a marker of sexually dimorphism in the control of ventilation) were evaluated and body weight, testes weight, and nose-anus length were measured in animals in each group. The EB-treated rats had similar tidal volumes, frequency of breathing, and minute ventilation as did control male rats. The ventilatory responses of EB-treated rats to hypercapnia were markedly less than those of control animals. Aspartic acid administration depressed ventilation in control animals, but had no effect on ventilation in EB-treated males. Body and testes weights, as well as nose-anus length, were less in EB-treated compared with control rats. However, when body weight was normalized by nose-anus length and testes weight was normalized by body weight, the values were comparable between the two groups. Thus, perinatal EB treatment of male rat pups results in small, hypogonadal adult animals whose ventilation in response to hypercapnia was diminished and whose response to aspartic acid was female-like relative to those of control rats.

Colorectal surgeons in district general hospitals produce similar survival outcomes to their teaching hospital colleagues: review of 5-year survivals in Manchester

A study of 578 patients treated for colorectal cancer in the North-west region comparing survival after surgery in teaching and non-teaching hospitals was performed. All patients had a minimum of 5 years follow-up. A greater proportion of elderly and emergency patients were treated in the non-teaching hospitals. The number of operative mortalities and 5-year survival figures for all causes of death and for colorectal deaths alone were similar in teaching and non-teaching hospital patients.

Nature, reliability, and predictive value of muscle performance measures in patients with hemiparesis following stroke

The purposes of this investigation were to examine among a sample of hemiparetic stroke patients the nature and reliability of selected muscle performance measures and the correlation between the measures and gait speed. Fourteen subjects who met specific entry criteria participated. The Lido Active Rehabilitation System was used to obtain bilaterally all muscle performance measures of knee extension (velocity, isometric torque-peak and time specific, and time to peak torque and 90% peak torque). Gait speed was measured under both "comfortable" and "maximum safe" conditions. In addition to lower torques, the subjects demonstrated slower knee extension speeds and longer times to peak torque and 90% peak torque on the paretic than on the nonparetic side. High intrasession reliabilities were demonstrated for all muscle performance measures except the torque at 0.1 sec on the nonparetic side and the time to peak torque and 90% peak torque measures. Significant correlations were demonstrated between both gait speeds and paretic knee extension torque (except at 0.1 sec), nonparetic knee extension torque at 0.1 sec and 0.2 sec, and time to nonparetic peak torque. Muscle performance measures other than peak torque appeared to offer little advantage (alone) over paretic peak torque for predicting gait speed. Over 74% of the variance in gait speed, however, could be predicted by the peak isometric peak torque of the paretic side and the time to peak torque on the nonparetic side, together. Thus, there may be benefits to testing the muscle performance of both lower extremities when examining patients with stroke.

A psychodrama group for health workers

Although much has been written about psychodrama as a therapeutic and educational method with patients, there is little evidence of its effectiveness as an activity for professional clinicians. The authors describe how the basic elements, phases and techniques of psychodrama have been used with groups of health workers to improve their clinical performance and personal life. The therapy has important applications in helping staff come to terms with the emotional stresses of their work with patients.

Immobilization alters cell metabolism in an immature ligament

This investigation examined the metabolic and cellular effects of immobilization on immature rabbit medial collateral ligaments (MCLs). Thirty-two three-month-old rabbits had their right knee pinned in flexion for intervals of two weeks, one month, two months, or three months before being killed for comparison with MCLs from nonpinned contralateral controls and MCLs from 16 normal age-matched controls. Twelve animals were studied by gait analysis after either one month or three months of immobilization and were killed with the others for in vitro analysis of ligament mass, collagen synthesis, plasminogen activator secretion, or DNA content. Immobilized hindlimbs carried less weight than did contralaterals, and MCLs from those hindlimbs synthesized less collagen and secreted less plasminogen activator than did controls at all intervals. Contralaterals also showed some signs of altered cell metabolism compared with normal controls, suggesting that they are not normal by these assessment criteria. With increasing periods of knee immobilization, immobilized MCLs switched progressively from an anabolic to a more catabolic state, apparently contributing to the failure of immobilized ligaments to increase normally in mass. Knee immobilization alters the metabolic behavior of MCLs in both knees in growing rabbits, and, based on these results, either knee joint motion or hindlimb load bearing could be necessary for normal rabbit medial collateral ligament growth and maturation.

Ventricular tachycardia rate and morphology determine energy and current requirements for transthoracic cardioversion

BACKGROUND

The electrical current and energy required to terminate ventricular tachyarrhythmias are known to vary by arrhythmia: Ventricular tachycardia (VT) is generally considered to require less energy than ventricular fibrillation (VF). The hypothesis of our study was that current requirements for transthoracic termination of VT are further determined by VT rate and QRS complex morphology.

METHODS AND RESULTS

We prospectively studied 203 patients who received a total of 569 shocks for VT or VF by following a current-based protocol. This protocol recommended shocks for VT beginning at 18 A (70 +/- 22 J) and shocks for VF beginning at 25 or 30 A (137 +/- 52 J or 221 +/- 70 J). The ventricular tachyarrhythmias were subclassified as monomorphic VT (MVT): uniform QRS complex morphology on surface electrocardiogram and heart rate greater than 100 beats per minute; polymorphic VT (PVT): nonuniform QRS complex morphology and heart rate less than or equal to 300 beats per minute; or VF: nonuniform QRS complex morphology and heart rate greater than 300 beats per minute. We found that shocks of 18 A and 25 A for terminating MVT had success rates of 69% and 82%, respectively, whereas such low-current shocks were less successful for PVT (33% at 18 A) and for VF (19% at 18 A, 53% at 25 A). High-current shocks of 35 A and 40 A were equally successful for the three ventricular tachyarrhythmias. Subdividing MVT revealed that slower MVT (heart rate less than 200 beats per minute) had a significantly better success rate with low-current shocks of 18 A and 25 A than did faster MVT (greater than 200 beats per minute) (89% versus 72% success, p less than 0.01). Bundle branch block morphology, QRS axis, and duration of ventricular tachyarrhythmia did not alter current requirements.

CONCLUSIONS

Heart rate and electrocardiographic degree of organization of ventricular tachycardia are important determinants of transthoracic energy and current requirements for cardioversion and defibrillation. Transthoracic termination of MVT requires relatively low current or energy, but PVT behaves more like VF and requires higher electrical current or energy.

Similarities and differences between MMPI and MMPI-2 applications to the assessment of posttraumatic stress disorder

The purpose of this study was to address the question: Is the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) comparable to the original MMPI in its applicability to the assessment of posttraumatic stress disorder (PTSD) among Vietnam combat veterans? The question was addressed by administering both the original MMPI and MMPI-2 to 29 subjects classified as meeting Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.; DSM-III-R) criteria for PTSD and comparing MMPI and MMPI-2 scores in terms of: degree of association, code-type congruence, diagnostic hit rates (when compared to two other clinical samples, and one normal sample), and congruence of the Keane PTSD Scale (PK). Results reveal highly significant correlations between MMPI and MMPI-2 basic scales for the PTSD sample as well as congruence in 2-point codes comparable to previous studies. The MMPI-2 was found to identify effectively PTSD subjects from the other groups. Results also showed a high degree of association between the MMPI and MMPI-2 in regard to PK scores, although minor differences were found in PK raw scores between the two tests. Overall, the findings suggest a high degree of comparability between the MMPI and MMPI-2 in the assessment of PTSD.

Curative resection: the major determinant of survival in patients with large bowel cancer

Data collected prospectively from 578 patients with colorectal cancer managed by 12 Manchester surgeons were analysed to evaluate the effects on survival of prognostic, clinical and pathological factors. Available preoperative and perioperative factors were included in a stepwise regression analysis and curative resection was found to be most strongly associated with patient survival. Other variables ranked according to their relative importance were performance status, weight loss and sex. The finding of the study supports the need to establish an early diagnosis if long-term survival results are to improve.

Pharmacokinetics of ampicillin-sulbactam in healthy elderly and young volunteers

The pharmacokinetics of ampicillin-sulbactam in elderly subjects (65 to 85 years; group 3, n = 8), compared with those in middle-aged (41 to 64 years; group 2, n = 8) and younger (20 to 40 years; group 1, n = 8) subjects, were investigated. A single 2-g dose of ampicillin combined with 1 g of sulbactam in 60 ml of intravenous solution was administered to each subject over a 30-min period. Blood and urine samples were taken at baseline and serially over an 8.5-h period following the infusion. Ampicillin and sulbactam concentrations were assayed by high-performance liquid chromatography on a reversed-phase C-8 column. The mean levels in serum of both ampicillin and sulbactam were significantly higher for samples from group 3: for ampicillin from 1 through 8.5 h, and for sulbactam for the same time interval except at 5.5 h (P less than or equal to 0.05). The mean urinary excretion of both ampicillin and sulbactam was lowest, and urinary concentrations were highest in group 3. The areas under the serum drug concentration-time curve, the half-lives, and the maximum concentrations in serum were greatest, while the total clearance was lowest, for group 3 for both ampicillin and sulbactam. These results are consistent with a prolongation of antimicrobial activity of ampicillin-sulbactam in the elderly compared with that in younger subjects.

Risk factors and operative mortality in surgery for colorectal cancer

The operative mortality rate after surgery for colorectal carcinoma remains significant. A series of 578 patients has been studied prospectively. The features which most significantly affect operative mortality are the age of the patient, a history of loss of weight, limited preoperative patient mobility and the presence of intestinal obstruction with perforation of the bowel. By identifying high-risk groups of patients, attention may be focused on particular patients at risk, in order to reduce operative mortality.

Production and characterization of osteoclast-selective monoclonal antibodies that distinguish between multinucleated cells derived from different human tissues

Osteoclastoma-derived giant cells were used to produce 11 mouse monoclonal antibodies (MAb) reactive against human osteoclasts on undecalcified sections of adult human bone. All exhibited unique reactivities across a wide range of human tissues. Three in particular demonstrated distinctive reactivities; C35 was highly selective for bone osteoclasts, C27 showed selective reactivity for osteoclasts, tissue macrophages and blood-borne monocytes, and C22 showed selective membrane staining of osteoclasts. Consequently, C22 was used to coat Dynabeads to affinity-purify viable human osteoclasts from osteoclastoma-derived cell suspensions. Immunocytochemical staining of inflammatory osteoarthritic synovium/granulation tissue demonstrated positivity in the majority of giant cells with MAb C22 and C27. In contrast, C35 reacted with only very occasional giant cells. Furthermore, multinucleated cells formed in long-term human bone marrow cultures demonstrated similar selective staining. C27 stained all giant cells and the majority of mononuclear cells. C22 detected only a small proportion of giant cells. In contrast to its staining on bone osteoclasts, C22 demonstrated granular cytoplasmic staining in cultured giant cells. C35 stained no cells at all in these cultures. These MAb can therefore distinguish between giant cells of various origins and authentic mature osteoclasts. Alternatively, they can recognize antigens expressed at different stages of osteoclast differentiation and therefore provide an excellent tool for the study of the human osteoclast lineage.

Effects of oxidants on lens transport

Hydrogen peroxide is associated with the development of cataracts. As an oxidant, it can act on the sulfhydryl groups of proteins and alter the transport properties of membranes. A nearly impermeant sulfhydryl binding agent is p-chloromercuriphenylsulfonate (p-CMPS). The changes in the current-voltage relationship of the equatorial potassium current produced by hydrogen peroxide and p-CMPS are similar. The authors studied the effects of p-CMPS to determine the possible effects of binding extracellular sulfhydryl groups. With a vibrating probe and microelectrodes, the authors saw three sequential effects of 0.5-5.0 microM p-CMPS. The first phase was a shift of the reversal potential, which is equivalent to the potassium equilibrium potential, to more negative values. The current-voltage relationship (J vs PD) shifted in a manner opposite to that produced by ouabain. The 86Rb uptake was stimulated. Ouabain blocked this initial phase. The second phase was a decrease in the resistance. The effects seen were similar to those described in other tissues after the intracellular injection of small amounts of Ca++. This second phase was inhibited by the removal of Ca++ from the medium and also by the addition of quinine to the medium. The third phase consisted of a depolarization of the lens. This effect has been described by others with larger concentrations of p-CMPS and is accompanied by an influx of Na+ and Ca++. The results suggested that micromolar quantities of extracellular p-CMPS sequentially stimulate the Na, K-pump; activate Ca(++)-dependent K+ channels; and open nonspecific channels. It is suggested that the second phase may play a role in cateractogenesis.

A quantitative analysis of matrix alignment in ligament scars: a comparison of movement versus immobilization in an immature rabbit model

This investigation quantified the alignment of fibrillar matrix in normal rabbit medial collateral ligaments (MCLs) and in healing MCLs from animals treated with or without knee immobilization. Twenty-four immature female rabbits were given complete midsubstance injuries to their right MCLs. Fifteen of them had that knee pin immobilized in flexion, while the remaining nine were allowed unrestricted cage activity. Animals were sacrificed in groups of three at intervals of 3, 6, or 14 weeks after injury, and both healing MCLs and unoperated contralateral controls were fixed in situ for subsequent removal, freeze-fracture, and preparation for scanning electron microscopy (SEM). A random sampling of SEM photographs followed by automated, statistically validated image processing was used to quantify alignment of matrix in all samples. Results showed that nonimmobilized MCL scars in this model do remodel over 14 weeks of healing, returning to normal alignment values in that time. Surprisingly, MCL scars in immobilized knees were even better, with mean matrix alignments falling statistically within normal MCL limits at all healing intervals studied. If not due to an unknown sampling or fixation artifact, these results suggest that gross knee flexion and extension is not a prerequisite for scar matrix alignment in this immature model of ligament healing.

Large granular T lymphocytes, neutropenia and polyarthropathy: an underdiagnosed syndrome?

Thirteen patients with expansion of an unusual subset of T lymphocytes, defined by large size, cytoplasmic granularity and CD3+ CD8+ Leu 7+ surface phenotype, are reported. Although morphologically and/or phenotypically abnormal lymphocytes were found in all patients, only five had an absolute peripheral blood lymphocytosis. Ten patients had a bone marrow lymphocytosis. As in previous series, there was a strong association with neutropenia (12 patients) and polyarthropathy (seven patients). The latter group displayed a wide range of articular disease: classical or definite rheumatoid arthritis in four patients and milder non-erosive disease in the remainder. All 13 patients showed evidence of abnormal B cell function: IgM rheumatoid factor was present in nine patients, neutrophil-specific antibodies in six and all showed an increased level of at least one immunoglobulin isotype. These patients may be difficult to distinguish from those with idiopathic neutropenia and Felty's syndrome. Such a distinction may not be made on clinical grounds alone: critical assessment of lymphocyte morphology, bone marrow examination and analysis of lymphocyte phenotype should be considered in all patients with unexplained neutropenia, particularly in the context of arthritis. It is suggested that the true prevalence of this syndrome may have been greatly underestimated.

EGTA modulates equatorial currents in frog lenses

A combination of a vibrating probe with microelectrodes was used to study the effects on the equatorial K+ current, J, of perturbing the frog lens by removing Ca2+ from the bathing medium. The results were different in the absence and presence of EGTA. In the absence of EGTA the reversal potential (PDJ = 0) remained near the Nernst potential; the input resistance, R, and the resistance of the segment of the K+ current loop being studied, RJ, decreased; the driving force (PD - PDJ = 0) increased; and J increased fourfold. In the presence of EGTA J did not increase more than twofold; the current-voltage relationship became linear; RJ did not decrease and both the PD and the reversal potential, PDJ = 0, became less negative with time. These findings, which are dependent on the use of the vibrating probe, were unexpected, and they were explored by studying the effects of removing Na+ from the medium. Substituting TMA for Na+ did not increase J. Removal of Ca2+ and the addition of EGTA to a Na+-free medium in which frog lenses were bathed resulted in a decrease in RJ, and an increase in J; J varied inversely with the concentration of Na+ in the medium. The changes were reversible. A mechanism to account for the changes is proposed.

Hoarse cry with fatal outcome

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An investigation of the effects of heat and water exchange in the recovery period after exercise in children with asthma

It has been reported that asthma provoked by breathing subfreezing air during exercise is enhanced when air at BTPS is inhaled in the recovery period (1). It was concluded that the rate of airway rewarming is an important event in asthma provoked by exercise. It is also possible, however, that the enhanced response was due to hypo-osmolarity caused by condensation of water from inspired air at BTPS on the cooled mucosa. We examined, in a group of boys with asthma, the response to rapid rewarming of the airways after exercise, with and without the potential for condensation. On two test days, two exercise tests were performed 4 h apart on a cycle ergometer. On Day 1 (n = 17), the inspired air during exercise was -5 degrees C, dry. During recovery, the air was either -5 degrees C, dry or 50 degrees C, 23 mg H2O/L. On Day 2 (n = 11), the inspired air during exercise was -15 degrees C, dry, and during recovery was either -15 degrees C, dry or at BTPS. We did not find enhancement of the response with either condition designed to cause rapid airway rewarming. On Day 1 the mean (+/- 1 SD) percent fall in FEV1 was 23 +/- 22 (-5 degrees C, dry) and 24 +/- 21 (50 degrees C, 23 mg H2O/L) (r = 0.92), and on Day 2 it was 19 +/- 17 (-15 degrees C, dry) and 18 +/- 17 (BTPS) (r = 0.96).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two prophylactic single-dose intravenous antibiotic regimes in the treatment of patients undergoing elective colorectal surgery in a district general hospital

Two hundred and twenty-nine patients were entered into a study to compare the effectiveness and safety of two single-shot antibiotic regimes in patients undergoing elective colorectal surgery in two district general hospitals. A single shot of intravenous (IV) latamoxef disodium was as effective as an IV combination of cefuroxime and metronidazole in control of wound infection following elective large bowel surgery when given as a bolus at the time of anaesthetic induction. The incidence of major wound infection was 6% and was evenly distributed in the two treatment groups. Half the major wound infections were associated with faecal fistulae. A single shot of IV antibiotic at the time of anaesthetic induction was safe, simple and an effective prophylaxis against major wound infection. There was a low incidence (1.3%) of serious postoperative bleeding and no serious adverse reactions were noted. The overall mortality was 9%. Death was significantly related to elderly patients, a poor performance status, operative contamination and wound infections.

Effect of ouabain on lens equatorial currents

The equatorial potassium current measured with the vibrating probe is a segment of the potassium electrical loop. The equatorial current, J, was measured simultaneously with the PD and with the response to an injected current, I. The injection of sufficient inward current, I, made the PD more negative and increased the electrical gradient so that the current J became zero. The PD at which this occurs (PDJ-0) is the reversal potential. Following treatment with ouabain, the PD and PDJ-0 both become less negative. Since the driving force for the current, J, is equal to the difference between PD and PDJ-0, J may increase, stay the same or decrease depending on the relative changes in PD and PDJ-0. In the presence of ouabain, the PDJ-0 changes in parallel with or more rapidly than the PD.

The use of hospital beds for terminally ill cancer patients

A study to identify reasons for admitting terminally ill cancer patients to hospital is reported together with recommendations for the future. Forty per cent of patients were so seriously ill with pain, medical or nursing problems that their carers could not manage satisfactorily at home and hospitalisation was necessary and appropriate. In addition 27% of patients admitted had no family or carers to nurse them at home. In the remaining 33% of patients it may have been possible with planned admissions and better supportive communications to allow some patients to die at home. Analysis of the data would suggest that there are three principal reasons for continuing to provide hospital beds for the terminally ill cancer patient: 1. Special medical and nursing care. 2. To provide care for some patients with no family or friend carer support. 3. Teaching of management by senior staff. The unsatisfactory nature of terminally ill patients dying in the centre of acute wards together with inadequate facilities to interview relatives is noted. It is suggested that the provision of well planned hospital beds is more appropriate than providing remote hospice beds for the terminally ill cancer patient.

Two methods of ligament injury: a morphological comparison in a rabbit model

Our purpose in this study was to compare morphologically the reproducibility and control of two common methods of ligament injury. Polarized light and scanning electron microscopy were used to quantify the injury patterns and the extent of ligament damage caused by scalpel division and wire rupture of rabbit medial collateral ligaments. Results demonstrate that the scalpel cut and wire rupture methods of ligament injury are each controllable and reproducible in location, pattern, and extent of ligament damage. The wire rupture technique, however, produced consistently more extensive midsubstance ligament damage than the scalpel cut and thus created an injury pattern that better simulated the extent of damage seen in clinical injuries. Although neither technique was an ideal simulation of clinical injuries, results suggest that the wire rupture technique is a more relevant technique to study ligament injury and healing in this model.

Operative mortality rate and surgery for colorectal cancer

Different authors use different definitions of operative mortality rate when reporting results of their operations. Four definitions used in current literature were applied to our own series of 578 patients with colorectal carcinoma. The operative mortality rate was found to vary from 7.3 per cent to 12.2 per cent, depending on the definition used. 'Death within 30 days of the last operation' was the definition which best reflected true operative deaths. We urge that this definition of operative mortality rate be adopted as a standard for all operations.

An ELISA for the detection of anti-acetylcholine receptor antibodies using biotinylated alpha-bungarotoxin

An antibody-capture enzyme immunoassay has been developed for the detection of anti-acetylcholine receptor (AChR) antibodies in tissue culture supernatants using biotinylated alpha-bungarotoxin (B alpha BGT). Immunoglobulins in culture supernatants were bound indirectly to microtitre plates via an anti-globulin antibody already coupled to polyvinyl plates. Anti-AChR antibodies were then detected by incubation with AChR crude extract. Bound AChR was revealed by incubation with B alpha BGT followed by horseradish peroxidase-conjugated avidin. This assay is specific, more sensitive than the commonly used double antibody radioimmunoassay, avoids the use of radioactive material, is practical for large numbers of samples and is particularly suitable for detecting anti-AChR antibodies in tissue culture supernatants.

Equatorial potassium currents in lenses

Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K+ concentrations across the membrane responsible for J is unchanged. Therefore, the decrease in PD is ascribed to an increase in Na+ permeance with a resultant increase in driving force accounting for the increase in J.