New mechanism that accounts for position sensitivity of saccades evoked in response to stimulation of superior colliculus

New mechanism that accounts for position sensitivity of saccades evoked in response to stimulation of superior colliculus. J. Neurophysiol. 80: 3373-3379, 1998. Electrical stimulation of the feline superior colliculus (SC) is known to evoke saccades whose size depends on the site stimulated (the "characteristic vector" of evoked saccades) and the initial position of the eyes. Similar stimuli were recently shown to produce slow drifts that are presumably caused by relatively direct projections of the SC onto extraocular motoneurons. Both slow and fast evoked eye movements are similarly affected by the initial position of the eyes, despite their dissimilar metrics, kinematics, and anatomic substrates. We tested the hypothesis that the position sensitivity of evoked saccades is due to the superposition of largely position-invariant saccades and position-dependent slow drifts. We show that such a mechanism can account for the fact that the position sensitivity of evoked saccades increases together with the size of their characteristic vector. Consistent with it, the position sensitivity of saccades drops considerably when the contribution of slow drifts is minimal as, for example, when there is no overlap between evoked saccades and short-duration trains of high-frequency stimuli.

An anatomical substrate for the spatiotemporal transformation

The purpose of the present experiments was to test the hypothesis that the metrics of saccades caused by the activation of distinct collicular sites depend on the strength of their projections onto the burst generators. This study of morphofunctional correlations was limited to the horizontal components of saccades. We evoked saccades by stimulation of the deeper layers of the superior colliculus (SC) in alert, head-fixed cats. We used standard stimulus trains of 350 msec duration, 200 Hz pulse rate, and intensity set at two times saccade threshold in all experiments. Evoked saccades were analyzed quantitatively to determine the amplitude of the horizontal component of their "characteristic vectors". This parameter is independent of eye position and was used as the physiological, saccade-related metric of the stimulation sites. Anatomical connections arising from these sites were visualized after anterograde transport of biocytin injected through a micropipette adjoining the stimulation electrode. The stimulation and injection sites were, therefore, practically identical. We counted boutons deployed in regions of the paramedian pontine reticular formation reported to contain long-lead and medium-lead burst neurons of the horizontal burst generator. Regression analysis of the normalized bouton counts revealed a significant positive correlation with the size of the horizontal component of the characteristic vectors. This data supports a frequent modelling assumption that the spatiotemporal transformation in the saccadic system relies on the graded strength of anatomical projections of distinct SC sites onto the burst generators.

Biventricular repair for double-outlet right ventricle. Results and long-term follow-up

BACKGROUND

The purpose of the present study was to define the optimal management and to identify the risk factors for death and repeat operation in patients with double-outlet right ventricle.

METHODS AND RESULTS

From 1985 through 1996, 154 consecutive patients underwent biventricular repair for double-outlet right ventricle. The presence of bilateral infundibular structures was the major inclusion criteria (142 patients). According to the relationship of the ventricular septal defect (VSD) to the great arteries, there were 86 patients with a subaortic VSD (56%), 45 patients with a subpulmonary VSD (29%), 18 patients with a noncommitted VSD (12%), and 5 patients with a doubly committed VSD (3%). Sixty-five patients (42%) had undergone previous palliative procedures. At repair, the median age was 10 months, and the median weight was 6.5 kg. Two main types of repair were used: intraventricular baffle repair (n = 115) and arterial switch operation with VSD-to-pulmonary artery baffle (n = 39). There were 14 hospital deaths (9%; 70% confidence limit [CL], 7% to 12%). The only significant risk factor for early death was the presence of congenital mitral valve anomalies (P = 0.02). Twenty-eight patients (18%) required 39 repeat operations. The repeat operation rate was higher in patients with associated VSD enlargement at baffle construction (n = 29; 19%) (P = 0.01). There were 6 late deaths (4%; 70% CL, 2% to 7%). Patients presenting with pulmonary stenosis constituted a low-risk group for global death (P = 0.008). The median follow-up was 52 months. Ten-year actuarial survival and survival with freedom from repeat operation rates were 86% and 62% (70% CL, 83% to 89% and 54% to 70%), respectively.

CONCLUSIONS

Long-term survival with good quality of life can be achieved after either 1- or 2-stage repair of this complex anomaly.

[Kidney procurement from a heart-arrest donor]

Brain death occurred in a 47-year-old head trauma patient following 5 days of intensive care. The procedure for multiple organ procurement was initiated. Irreversible cardiac arrest had occurred during the period in the surgical intensive therapy unit. External cardiac massage and mechanical ventilation were maintained until in situ cooling of the kidneys was achieved. The patient was taken to the operating room for nephrectomy. Both kidneys were transplanted with a favorable outcome. Procurement of kidneys from non-heart-beating donors could increase the number of available grafts for transplantation.

[Primary renal chondrosarcoma: apropos of a case]

The authors report a case of primary renal chondrosarcoma associated with subcapsular renal haematoma. The authors reviewed the four largest series of renal sarcomas reported in the literature and propose an analysis of the various clinical characteristics, complementary investigations and treatment modalities of this exceptional form of renal sarcoma.

Comparison of static fusimotor innervation in cat peroneus tertius and longus muscles

Static fusimotor innervation was compared in cat peroneus longus and tertius muscles because the gamma to spindle ratio is considerably higher in the longus (approximately 60 gamma axons for 17 spindles) than in the tertius (approximately 24 gamma axons for 14 spindles). Single gamma axons were identified as static (gamma(s)) by their typical effects on the response of primary ending to ramp stretch. The intrafusal muscle fibers that single gamma(s) axons activated in the spindles they supplied were identified by the features of cross-correlograms between Ia impulses and stimuli, at 100 Hz, and by those of primary ending responses during stimulation at 30 Hz. In each experiment, a large proportion of the gamma population was tested on about nine spindles. A statistical analysis was used to estimate the number of spindles supplied by single gamma(s) axons and the proportion of gamma(s) axons that supply only one spindle among those the stimulation of which had activated either bag2 or chain fibers alone in a single spindle. In peroneus longus, nearly all gamma(s) axons supply one or two spindles, whereas in peroneus tertius, the majority of gamma(s) axons supply from three to six spindles. The proportion of nonspecifically distributed gamma(s) axons, i.e., of axons that supply both bag2 fibers and chain fibers either in the same or in different spindles, is much lower (56%) in the longus than in the tertius (83%) as previously observed on a population of gammas axons that supplied from three to six spindles. Correspondingly, the proportion of specific axons is much higher in the longus (44%) than in the tertius (17%). In none of the two muscles was a strict relationship observed between the conduction velocity of gamma(s) axons and their intrafusal distribution (specific bag2, specific chain fibers, nonspecific). However, gamma(s) supplying bag2 fibers either specifically or in combination with chain fibers tended to have faster conduction velocities, which suggests that, in various motor acts, the proportion of activated bag2 and chain fibers may be related to the proportions of activated fast and slow gamma(s) axons.

[Long-term stability of bone mineral density in patients with renal transplant treated with cyclosporine and low doses of corticoids. Protective role of cyclosporine?]

OBJECTIVES

Cyclosporine has been thought to have a deleterious effect on bone in transplant recipients because of high turnover osteopenia observed in humans after transplantation. However, varying confounding factors such as renal and parathyroid function, cumulative steroid doses and previous exposure to aluminium, also play a role and hinder interpretation of the cyclosporine effect on bone mineral density (BMD).

PATIENTS AND METHODS

A 2-year prospective study was conducted to measure BMD starting 3 months after transplantation and bone remodeling markers from the first post-transplantation day in 52 kidney recipients with no prior exposure to aluminum. None of the patients experienced rejection and at 3 months all had good stable renal function (serum creatinine 137 mumol/l) and mildly elevated parathyroid hormone levels (1.5 times the upper limit of normal). All patients were given the same low dose steroid treatment (10 mg/day) and at 6 months cyclosporine was decreased from 7 to 4.8 mg/kg/day.

RESULTS

BMD measured by double energy X-ray absorptiometry, (DEXA) and expressed in Z score, was moderately decreased at 3 months for the vertebrae (-1.40), the femoral neck (-1.34) and the ultradistal radius (-0.95) which have predominantly cancellous bone and was significantly less decreased (p < 0.05) for the lower third of the radius (-0.6) which is mainly cortical bone. BMD measurements were comparable at 6, 12 and 24 months. When measured by axial computerized tomography (ACT) BMD of the vertebrae showed a non-significant increase of Z score from -1.37 to -1.19 at 2 years. Bone remodeling markers was observed up to month 6 (from month 3 for osteocalcine and from month 1 for total and bone alkaline phosphatase and urinary pyridinoline), then returned to baseline levels at 2 years in parallel with decreased cyclosporine dosage. The increase of vertebral BMD measured by ACT at 1 year was correlated both to cyclosporine dose at 1 year and to bone alkaline phosphatase at 6 months.

CONCLUSION

Our data confirm the presence of moderate osteopenia 3 months after transplantation, predominantly in trabecular bone, logically linked to the initial high doses of corticosteroids. The long-term stability of BMD measured by DEXA and the correlation of vertebral BMD increase measured by ACT with cyclosporine dose and bone alkaline phosphate suggest that cyclosporine had a beneficial immunosuppressor effect by stimulating bone remodeling and thus counterbalancing the suppressive effect of corticosteroids.

Induction and modulation of acute-phase response by protein malnutrition in rats: comparative effect of systemic and localized inflammation on interleukin-6 and acute-phase protein synthesis

The acute-phase protein (APP) response is regulated by cytokines such as interleukin-6 (IL-6), interleukin-1 (IL-1) and tumor necrosis factor (TNF), but may also be influenced by malnutrition. The aims of this study were as follows: 1) to determine in rats the effect of a protein-deficient diet on IL-6 mRNA expression in intestine, liver and peripheral blood mononuclear cells (PBMC), and on alpha-1 acid glycoprotein (AGP) and alpha-2 macroglobulin (A2M) serum levels and hepatic mRNA expression; 2) to compare, in protein-deficient rats, the IL-6 and APP responses after a turpentine (TO)- or a lipopolysaccharide (LPS)-induced inflammation; and 3) to determine the effect of a protein malnutrition on IL-6 mRNA expression in rat PBMC treated ex vivo with LPS. Interleukin-6 mRNA was present in intestine and PBMC but not in the liver of malnourished rats, and was absent in any tissue or cells of controls. A2M was present in the serum from malnourished rats but not after refeeding. AGP mRNA expression was not influenced by protein malnutrition. In malnourished rats, IL-6 serum level peaked later than in controls after TO and LPS treatment. In malnourished TO-treated rats, A2M mRNA increased earlier than in controls and remained detectable later than in controls. AGP mRNA expression after TO was not influenced by protein malnutrition. In PBMC of malnourished rats, LPS-induced IL-6 mRNA expression occurred earlier and lasted longer than in controls. Our results indicate that protein malnutrition by itself induces IL-6 and A2M expression, and that it modulates the APP response to inflammation.

A randomized comparison of the clinical and hormonal effects of two GnRH agonists in patients with prostate cancer

OBJECTIVE

The aims of the study were (i) to compared the efficacy of the two long-acting GnRH agonists (GnRHa) triptorelin (Trp) and leuprolide (Leu) in men with prostate cancer and (ii) to assess the pattern of plasma testosterone levels following each injection of GnRHa.

PATIENTS AND METHODS

67 patients referred for prostate cancer not suitable for surgery were randomly allocated to two treatment regimens: 33 patients received 3.75 mg Trp i.m. at 4-week intervals for 3 months and 34 patients were treated with 3.75 mg Leu s.c. at the same rhythm of administration for 3 months.

RESULTS

Clinical data at entry and assessed monthly during follow-up did not differ between the two groups. Plasma prostate-specific antigen (PSA) and testosterone were measured before, 24 and 72 h after each injection of GnRHa. During treatment, PSA dropped similarly in both groups. By month 2, testosterone was < 1.0 nmol/l in 77 and 48% of patients treated with Trp and Leu, respectively (p = 0.02). 24 and 72 h after GnRHa injection, 77 (Trp) and 56% (Leu) of patients had testosterone < 1.0 nmol/l (p < 0.05).

CONCLUSIONS

The second and third injections of GnRHa were not followed by a significant increase in testosterone. Trp induced a higher decrease in testosterone than did Leu. The implications in terms of survival should, however, be studied in a larger and longer study.

Biventricular repair of conotruncal anomalies associated with aortic arch obstruction: 103 patients

BACKGROUND

Biventricular repair of conotruncal anomalies associated with aortic arch obstruction is a complex surgical procedure that combines a cardiac repair and a aortic arch reconstruction.

METHODS AND RESULTS

From January 1984 to April 1996, such a repair was performed in 103 patients. The conotruncal anomalies included: 15 transpositions of the great arteries (TGAs) with intact ventricular septum, 44 TGAs with ventricular septal defect, 32 double outlet right ventricle with subpulmonary ventricular septal defect, 10 truncus arteriosus, one double outlet left ventricle, and one tetralogy of Fallot. The arch obstruction included 88 coarctation and 15 interrupted aortic arch. One-stage repair has been the favored technique since 1990 and was performed in 58 neonates, including 38 TGAs or double outlet right ventricle and ventricular septal defect, 10 TGAs with intact ventricular septum, and all of the 10 truncus arteriosus. The cardiac repair included 89 arterial switch operations, 2 Kawashima rerouting, 10 truncus arteriosus repairs, and one double-outlet left ventricle repair and one tetralogy of Fallot repair. The aortic arch was reconstructed by direct anastomosis in 85 patients, with a Gore-Tex conduit in three patients and more recently by an ascending aortic patch augmentation in 15 patients. The hospital mortality was 12% (7 of 58) for the one-stage repair and 20% (9 of 45) for the two-stage repair. There were six late deaths. Reoperations or angioplasties were mandatory for 12 right ventricle outflow tract obstructions after arterial switch, involving 10 patients with double outlet right ventricle (P=.02), 10 recurrent arch obstruction, and six miscellaneous lesions.

CONCLUSIONS

One-stage biventricular repair of conotruncal anomalies associated with aortic arch obstruction can be achieved in selected patients with an 83% survival rate at 7 years.

High incidence of chronic graft versus host disease after allogeneic peripheral blood progenitor cell transplantation. The Spanish Group of Allo-PBPCT

BACKGROUND AND OBJECTIVE

The incidence of acute GVHD (aGVHD) in allogeneic peripheral blood progenitor cell transplantation (allo-PBPCT) seems to be similar to that seen in allogeneic bone marrow transplantation (allo-BMT). In contrast, some preliminary results suggest that the incidence of chronic GVHD (cGVHD) might be higher. The aim of the present study was to analyze the actuarial probability of developing cGVHD in allo-PBPCT, its clinical manifestations and response to treatment.

METHODS

We have retrospectively analyzed clinical results from 21 allo-PBPCT recipients that had been transplanted at least 18 months before this study and that fulfilled the following criteria: HLA identical sibling donor, non T-cell depleted apheresis and more than 90 days of survival with sustained engraftment. The median follow-up was 12 months (range 4.5-22).

RESULTS

Twelve out of the 21 (57%) patients presented cGVHD, 1 limited and 11 extensive. The actuarial probability of cGVHD was 72.7% (95% CI, 49-96%). The median interval from transplant to onset was 180 days (range 95-270). Nine of the 12 cases (75%) presented combined skin and liver involvement. Of the other three, the liver was involved in one case; skin, mouth, and nail cGVHD was observed in another case; and skin and mouth involvement together with an obstructive pulmonary disease was observed in the remaining case. Under therapy, a complete resolution of cGVHD manifestations was achieved in five cases, and a partial improvement was attained in three other cases. In two responsive patients, cGVHD reappeared after stopping treatment. Four patients were refractory to the treatment.

INTERPRETATION AND CONCLUSIONS

It would appear from this retrospective and multicenter study that, after a median follow-up of 12 months, cGVHD after allo-PBPCT could be more frequent than after allo-BMT. A randomized trial with a large number of patients and a sufficient follow-up will be necessary to answer this question definitively.

Prevention of unbalanced lung perfusion and atrial arrhythmias after the lateral tunnel operation

BACKGROUND

The lateral tunnel operation has become increasingly popular with pediatric cardiac surgeons, as it is technically reproducible, is relatively easy to perform, and can be used in a variety of patients with single-ventricle physiology. The main drawbacks of the original operation are uneven blood flow distribution to the lungs and increasing incidence of supraventricular arrhythmias over time.

METHODS

In 1988, we modified this technique by avoiding narrowing of the tunnel at the superior vena cava-atrial junction, avoiding incorporation of the crista terminalis in the baffle suture line, and minimizing damage to the sinoatrial node. Between 1988 and 1995, 19 patients underwent this operation at Marie-Lannelongue Hospital in Paris.

RESULTS

There was one early death and no late deaths. At a mean follow-up of 5.2 years, all survivors are in New York Heart Association class I. Early atrial flutter, related to atrial scarring secondary to multiple previous surgical procedures, developed in 1 patient, and late atrial flutter developed in 1 patient who had a previous Blalock-Hanlon atrial septectomy. All patients are currently in sinus rhythm. Atrial flutter did not occur in 17 patients who had had no previous atrial wall surgical procedure.

CONCLUSIONS

We believe that the good long-term clinical results are directly attributable to our modifications, which ensure optimal hemodynamics and absence of rhythm disturbances. All patients who had not previously undergone operation on the atrial wall were free from supraventricular tachyarrhythmias at a mean follow-up of 5.2 years. This is a consequence of protecting the sinus node, crista terminalis, and Bachmann's bundle.

Primary central nervous system lymphoma of T-cell origin: description of two cases and review of the literature

Primary lymphomas of the central nervous system (PLCNS) of T-cell lineage are unusual. It has been suggested that T-cell PLCNS, compared to those of B-cell origin, present some differences in relation to age of presentation, gender, location of the tumor and survival. We describe two cases with T-cell PLCNS and review 22 parenchymatous T-cell PLCNS reported in the English literature. Age, gender and survival of the whole series of 24 T-cell PLCNS did not differ from that reported in large series of PLCNS where the great majority were of B-cell origin. In contrast, a location in the posterior fossa was found in 54% of T-cell PLCNS, whereas this location ranged from 12 go 29% in series of, mostly B-cell, PLCNS. T-cell PLCNS had a higher frequency (33%) of the histologic low grade small lymphocytic lymphoma than B-cell PLCNS (5%). Analysis of six T-cell PLCNS long-term survivors showed that half of them had low grade lymphomas. We conclude that T-cell PLCNS do not differ from those of B-cell origin in age of presentation or gender, but they have a preference to develop in the posterior fossa and a higher frequency of low grade histology which would probably explain the longer survival in some patients.

Technique to repair tetralogy of Fallot with absent pulmonary valve

The syndrome of tetralogy of Fallot with absent pulmonary valve is characterized by aneurysmal dilatation of the pulmonary arteries causing tracheobronchial obstruction of varying degree. Relief of this obstruction is the main goal of the surgical repair and can best be achieved by appropriate pulmonary arterioplasty. We describe our current technique to repair this syndrome in infants and older children including pulmonary arterioplasty, ventricular septal defect closure, and right ventricular outflow tract reconstruction without valve insertion.

Evaluation and management of polyneuropathy: a practical approach

Disorders of peripheral nerves are commonly encountered by primary health care providers. This article reviews one of the most frequent patterns, that is, polyneuropathy (PN). PN is a common but complex entity. Understanding the pathophysiology of axons, the classification of PN, the biologic targets of toxins and the patterns of PN assist in the diagnosis of PN. The pathophysiology, symptoms, and signs are discussed along with basic steps to be taken in the evaluation, diagnosis, and management. Illustrative case studies are provided. Diagnosis may not be possible in all cases. When the etiology is unknown, ongoing monitoring of the polyneuropathy is emphasized, particularly in acquired processes where the polyneuropathy may be associated with systemic disease. In such instances, care of the client is directed toward symptomatic management.

Tendon organ sensitivity to steady-state isotonic contraction of in-series motor units in feline peroneus tertius muscle

1. Measurements have been made of the sensitivity of tendon organs to steady-state, isotonic contractions of single and groups of in-series motor units in the peroneus tertius muscle of the cat hindlimb. 2. Linear relationships were found between the Ib afferent discharge and the contractile tension generated by tetanic stimulation of single motor units. These relationships held for the fast, fatiguable (FF) units and for all but the lowest tensions generated by the slow (S) and some fast, fatigue resistant (FR) units. The sensitivity of the organs was independent of the contractile properties of the units. 3. Groups of three motor units were stimulated isotonically at low rates (around 30 Hz), but asynchronously to produce a smooth tension profile. Again, linear relationships pertained between the discharge rate and the tension, and the sensitivity was the same for different motor unit types. 4. Under isotonic conditions, therefore, the tendon organs showed linear responses to the tension with similar sensitivities, indicating that tendon organs may have the capacity to signal faithfully steady-state contractile tensions.

Tension distribution of single motor units in multitendoned muscles: comparison of a homologous digit muscle in cats and monkeys

To determine whether single motor units (MUs) in multitendoned muscles distribute tension to multiple tendons or instead focus tension selectively on a single tendon, we examined the distribution of tension generated by single MUs in the cat extensor digitorum lateralis (EDLat), and in its macaque homolog, the extensor digiti quarti et quinti (ED45). General properties of MUs (maximal tetanic tension, axonal conduction velocity, and twitch rise time) were similar in these muscles to those reported for other limb muscles in cats and monkeys. Most cat EDLat MUs were found to exert tension rather selectively on one of the three tendons of the muscle. Fast fatigable MUs were slightly but significantly more selective than fast fatigue-resistant and slow MUs. In contrast, and contrary to expectation, the macaque ED45 contained a lower proportion of MUs that exerted tension selectively on one of the two tendons of the muscle, and a higher proportion of relatively nonselective MUs. These findings suggest that the cat EDLat may consist of three functional subdivisions, each acting preferentially on a different tendon, whereas the macaque ED45 is more likely to function as a single multitendoned muscle.

Functional consequences of bag2 and chain fiber coactivation by static gamma-axons in cat spindles

A study of the distribution in cat peroneus tertius spindles of 42 single static gamma-axons was recently carried out with a physiological method for identifying the intrafusal muscle fibers supplied by single gamma-axons. It was found that 35 axons (83%) supplied both slow-contracting bag2 fibers and fast-contracting chain fibers. The distribution of these axons generally varied from one spindle to another among all the spindles that each of them supplied (bag2 and chain fibers together, bag2 alone, chains alone). To find some functional consequences of this coactivation, responses of primary endings to sinusoidal stretch of the muscle (amplitude 0.5-1 mm, frequency linearly increasing from 0.6 to 8-9 Hz in 12 s) were recorded at different average muscle lengths (0.5, 1.0, and 1.5 mm shorter than maximal physiological length) in nembutalized cats during repetitive stimulation at 10, 20, and 30 Hz of single gamma-axons previously shown to supply bag2 and chain fibers in the spindles bearing the primary endings. These responses were compared with responses elicited in passive spindles and during activation of either bag2 fibers or chain fibers alone. Several records of discharge frequency were averaged. During stimulation at 30 Hz of gamma-axons coactivating bag2 and chain fibers, the averaged discharge of primary endings became continuous (that is, without interruption during each shortening phase as occurs in passive spindles) over the whole range of stretch frequencies. The modulation of the discharge was roughly sinusoidal, with an amplitude that increased with the stretch frequency. Stimulation at 30 Hz of gamma-axons activating bag2 fibers alone elicited a modulation of comparable shape and amplitude but only in the range of sinusoidal stretch from 0.6 to 3-4 Hz. Stimulation at 30 Hz of gamma-axons activating chain fibers alone elicited for each cycle in the range of 0.6 to 5-6 Hz a distorted modulation of large amplitude with a minimal frequency close to that of the stimulation. The average muscle length did not significantly influence these various responses. In summary, the coactivation of bag2 and chain fibers, at presumed physiological frequencies, enables primary endings to continuously signal changes of length over a large range of stretch velocities independently of the average muscle length.

[Acquired pulmonary vein stenosis after surgery of complex partial anomalous pulmonary venous drainage in an adult. Diagnostic value of transesophageal echocardiography]

Surgical correction of partial anomalous pulmonary venous drainage is difficult and may be complicated by acquired postoperative stenosis at the site of reimplantation of the pulmonary veins in the left atrium. Diagnosis should be made quickly because of the very poor prognosis due to acute pulmonary hypertension. The case described by the authors underlines the value of multiplane transesophageal echocardiography with two-dimensional and Doppler analysis for rapid and accurate diagnosis of this complication.

Mobilization of peripheral stem cells with intensive chemotherapy (ICE regimen) and G-CSF in chronic myeloid leukemia

Seventeen patients with Philadelphia (Ph) chromosome-positive chronic myeloid leukemia (CML) were treated with the ICE regimen plus G-CSF with the aim of mobilizing and collecting Ph-negative peripheral stem cells (PSC) in the setting of an autotransplant program. Fifteen patients had CML in first chronic phase (CP), and two in accelerated phase (AP). Three patients had been previously treated with interferon alpha 2a (IFN). Twelve patients underwent leukaphereses and a mean of 4.7 x 10(8)/kg mononuclear cells were obtained. Four CP patients did not show a significant mobilization peak of CD34+ cells and leukapheresis was not performed; finally, one patient died before apheresis could be performed. Six of the 12 who underwent leukaphereses obtained more than 1.0 x 10(6)/kg CD34+ cells. Eight of the 12 mobilized patients (67%) obtained a major cytogenetic response, including two complete and six partial; in the remaining four patients minimal or absent cytogenetic responses were observed. A higher rate of Ph purging was obtained in patients mobilized early or showing residual Ph-negative cells before mobilization, even if they were in AP. Infectious complications were frequent with a 38% rate of bacteremia recorded and one case of pulmonary aspergillosis resulting in a toxicity similar to that occurring in acute myeloid leukemia-induction chemotherapy. The ICE regimen can promote 'in vivo' purging of the Ph+ cells in 67% of CML mobilized patients (8/12). Failure of mobilization occurs in 65% of patients (11/17), mainly because of poor CD34+ cell yield.

Absent pulmonary valve syndrome: surgical treatment and considerations

BACKGROUND

The operative management of absent pulmonary valve syndrome remains controversial regarding the need for pulmonary valve implantation and remodeling of pulmonary arteries. Moreover, symptomatic infants are considered to have a poor prognosis. This retrospective report summarizes the experience of a single institution.

METHODS

Between May 1977 and May 1995, 37 consecutive patients underwent repair of absent pulmonary valve syndrome. Patients were divided into two groups according to age at operation: group A (10 infants less than 1 year old) and group B (27 patients older than 1 year). Mean age at operation was 5 +/- 4 months in group A and 72 +/- 42 months in group B. Initially, repair consisted of ventricular septal defect closure and relief of right ventricular outflow tract obstruction combined with pulmonary valve implantation. More recently, the concept of treatment has evolved with pulmonary arterioplasty without pulmonary valve insertion, except in patients with elevated pulmonary artery pressure.

RESULTS

Of the 37 patients, 34 had successful repair. The overall in-hospital mortality rate was 8% (two deaths in group A and one in group B). No hemodynamic data were correlated with operative death. Death was associated with longer extracorporeal circulation time (p = 0.005) and longer aortic cross-clamping time (p = 0.019). In fact, these were clearly related to more complex anatomy (p = 0.001): multiple ventricular septal defects in 1, left pulmonary artery arising from the ductus in another, and left pulmonary artery arising from the aorta in the remainder. Follow-up was available in 22 of the 34 survivors. Mean follow-up time was 30 +/- 47 months in group A and 38 +/- 33 months in group B. All but 1 had no restriction of exercise, and most of them had pulmonary incompetence of Doppler echocardiography. One developed severe exercise intolerance because of pulmonary valve stenosis (xenograft), leading to uneventful reoperation 123 months after initial repair. One infant died suddenly of complete atrioventricular block 3 months after repair. The late mortality rate was 5%.

CONCLUSIONS

Surgical treatment of absent pulmonary valve syndrome should include pulmonary arterioplasty to reduce bronchial obstruction, with no need for pulmonary valve insertion. This procedure is feasible and is recommended especially in markedly symptomatic infants.

Allogeneic peripheral blood progenitor cell transplantation: analysis of short-term engraftment and acute GVHD incidence in 33 cases. allo-PBPCT Spanish Group

The results of 33 allogeneic peripheral blood progenitor cells transplants (allo-PBPCT) in adult patients with hematologic malignancies were analyzed in a retrospective and multicenter study. In 21 of 33 cases (63%) the disease was refractory or in advanced stage and eight of the 33 cases (24%) were second transplants after relapse. Donors were treated with a median of 10 (4-16) micrograms/kg/day of rhG-CSF subcutaneously for 5-7 days. Three required a central venous line for harvesting. Peripheral blood leukapheresis product contained a median of 5.9 (1.8-13) 10(6)/kg CD34+ cells and a median of 309.5 (153-690) 10(6)/kg CD3+ cells. After a myeloablative regimen, all patients received PBPC from HLA-identical donors as the sole source of progenitor cells. Cyclosporin A (CsA) alone (n = 2), CsA and steroids (n = 9), and CsA and methotrexate (MTX) (n = 22) were used for GVHD prophylaxis. Growth factors post-transplant were given to 11 patients (33%). The median follow-up of the patients was 3 months. Actuarial median day for hemopoietic recovery was: neutrophils to >0.5 (>1) x 10(9)/l, day 14 (15); platelets to >20 (>50) x 10(9)/l, day 14 (21). The quantity of CD34+ cells infused did not significantly affect the engraftment kinetics, from a starting cutoff of 2.5 x 10(6)/kg. The speed of neutrophil recovery seemed to be influenced strongly by using rhG-CSF post-transplant and marginally by the type of GVHD prophylaxis. Actuarial probability for grade II-IV acute GVHD of the whole group was 37% (95% Cl, 20-54%).

Oligoblastic leukaemia with (8;21) translocation and haemophagocytic syndrome and granulocytic cannibalism

We report a 47-year-old man with oligoblastic leukaemia (8;21) translocation, phenomenon of cannibalism by granulocytic cells and haemophagocytic syndrome. The patient responded to intensive chemotherapy with disappearance of haemophagocytosis, granulocytic and histiocytic. We conclude that: (1) granulocytic cannibalism and haemophagocytic syndrome can be unusual myelodysplastic features; (2) the oligoblastic leukaemia with presence of cytogenetic abnormalities related to AML in young patients are probably more close to acute leukaemia than to myelodysplastic syndrome.

The dynamic response of feline Golgi tendon organs during recovery from nerve injury

The dynamic response of tendon organs to isometric contractions of activating motor units has been examined during recovery from nerve crush or nerve transection followed by suture repair. After nerve crush the characteristic response was rapidly restored, although the early and late phases of the dynamic response were altered differentially. Following nerve transection, recovery was much poorer and many responses were abnormal. Normal responses were only observed in a minority of tendon organ-motor unit interactions but every tendon organ studied did respond normally to at least one motor unit, with a range of dynamic sensitivities similar to normal. This suggests that the abnormalities observed reflect changes in the mechanical input to the organ, due to motor unit reorganisation, rather than abnormalities of the transduction process.

Feasibility and results of bone marrow transplantation after remission induction and intensification chemotherapy in de novo acute myeloid leukemia. Catalan Group for Bone Marrow Transplantation

PURPOSE

To evaluate prospectively the feasibility and results of bone marrow transplantation (BMT) after induction and intensification chemotherapy (CT) in patients with de novo acute myeloid leukemia (AML).

PATIENTS AND METHODS

A total of 159 patients less than 51 years of age were treated. Induction CT consisted of daunorubicin 60 mg/m2 for 3 days, cytarabine (ARA-C) 100mg/m2 for 7 days, and etoposide 100 mg/m2 for 3 days. The first intensification therapy included mitoxantrone 10 mg/m2 for 3 days and ARA-C 1.2 g/m2 every 12 hours for 4 days. Amsacrine (100 or 150 mg/m2 for 3 days) and ARA-C (1.2 g/m2 every 12 hours for 2 or 4 days) were given as the second intensification therapy. Depending on the availability of a human leukocyte antigen (HLA)-identical sibling, the intention of treatment after CT was allogeneic BMT (allo-BMT) or autologous BMT (ABMT).

RESULTS

Complete remission (CR) was obtained in 120 patients (75%) and partial remission (PR) in 11 (7%), while 15 patients (10%) were refractory and 13 (8%) died during induction. There was a trend for better leukemia-free survival (LFS) at 4 years for patients assigned to the ABMT group (50% +/- 6%) compared with the allo-BMT group (31% +/- 7%) (P = .08). This difference in LFS reached statistical significance when considering only transplanted patients (63% +/- 3% at 4 years after ABMT and 38% +/- 11% after allo-BMT, P = .02). The favorable results in patients who received ABMT (no toxic deaths and 37% +/- 7% probability of relapse at 4 years) contrast with the poor outcome of allografted patients (11 patients with transplant-related mortality).

CONCLUSION

Our study reflects the difficulties in the completion of a therapeutic strategy that include BMT and suggests that intensification before BMT may be useful in the setting of ABMT, but this approach was associated with a high mortality rate in allo-BMT patients.

The static sensitivity of tendon organs during recovery from nerve injury

An investigation has been carried out into the physiological properties of tendon organs and their interactions with motor units following two types of nerve injury: nerve crush and nerve transection followed by suture repair. Recovery from nerve crush was very successful: 6 weeks after the injury 60% of the tendon organ-motor unit interactions (n = 62) evoked normal or near-normal patterns of afferent discharge but with reduced firing rates. After 10 weeks of recovery 81% of the interactions (n = 43) were normal. The main abnormality observed was a phasic-only pattern of discharge. The overall reductions in firing rate during early recovery may be attributable to the lower contractile forces generated by the reinnervated muscle units, while the phasic-only responses may also represent immaturity of the transduction mechanism of the regenerated afferent axons. Following nerve transection the quality of recovery was much lower and a range of abnormal, as well as normal patterns of response were observed. For all the afferents studied, both types of response were recorded, suggesting that although there may be changes in the sensitivity of the afferents to muscle contraction, the abnormal responses more probably reflect changes in the form of the mechanical input rather than abnormalities of the transduction process.

[Percutaneous closure of patent ductus arteriosus: results and costs compared to surgical closure]

The comparison of the clinical results and costs of the two methods of closure of patient ductus arteriosus was undertaken in two comparable groups of 40 patients treated in the same period in the same hospital. After transcatheter closure there was a 9% residual shunt rate at 3 years, the 2 patients with a residual continuous murmur being operated secondarily. The only complication was severe haemolysis which regressed after transcatheter ablation of the prosthesis. After surgical closure, there were no residual shunt. Some postoperative complications were observed in 20% of cases, usually benign (ventilatory problems, dysphonia or urinary infection), but occasionally more serious (peroperative lesion of the pulmonary artery). Morbidity, inherent to the technique of closure, was very different and much less in catheter closure. The average cost (daily cost x average length of hospital stay) was much less with transcatheter closure 38,558 francs versus 11,240 francs. On the other hand, the direct cost of transcatheter closure was greater than that of surgery: 32,798 francs versus 20,903 francs, the difference being related to the actual price of the prosthesis. The authors conclude that the 3 year results of transcatheter closure of patent ductus arterious make this technique a reasonable therapeutic alternative to surgery. From the safety point of view, the two techniques are comparable bu patient confort is greater with transcatheter closure for an increase in cost of the initial procedure which should decrease in relation to the types and prices of the prosthesis used.

Transposition of the great arteries [S,D,L]. Pathologic anatomy, diagnosis, and surgical management of a newly recognized complex

The transposition of the great arteries [S,D,L] complex is delineated for the first time from the anatomic, diagnostic, and surgical standpoints in this study of 26 cases: 16 surgical and 10 postmortem. Transposition of the great arteries with situs solitus of the viscera and atria (S), D-loop ventricles (D), and L-transposition (L) was characterized by six additional interrelated anomalies that largely determined surgical management: (1) ventricular septal defect, usually conoventricular, in 96%; (2) malalignment of the conal septum, typically leftward and posteriorly, in 80%; (3) right ventricular hypoplasia in 50%; (4) pulmonary outflow tract stenosis in 27%; (5) ventricular malposition, such as superoinferior ventricles, in 23%; and (6) absent left coronary ostium resulting in "single" right coronary artery in 23%. Complete surgical repair was done in 81% of the surgical patients with a 12.5% hospital mortality rate and no late deaths. When there was no pulmonary outflow tract stenosis and intracardiac anatomy was uncomplicated, we undertook anatomic repair before 1 month of age. However, when pulmonary outflow tract stenosis coexisted, complete repair was deferred until after age 1 year, our currently preferred operation being the REV procedure (réparation a l'etage ventriculaire). When complex intracardiac anatomy precluded biventricular repair, a palliative procedure was performed in 19% without mortality. Hence, this experience indicates that surgical management of patients with the transposition of the great arteries [S,D,L] complex is feasible.

The dynamic response of Golgi tendon organs to tetanic contraction of in-series motor units

Golgi tendon organs (TOs) display a dynamic response related to the rate of tension development by the motor units (MUs) which activate each TO. When several MUs are activated together the response increases non-linearly with respect to tension. The dynamic response has been re-examined by recording the responses of TOs, in the adult cat, to tetanic, isometric contractions of one or more MUs and has been found to comprise two components: for each MU-TO pair the instantaneous frequency between the first two impulses of the response was linearly related to the rate of rise of the tension, the slope of the relationship being greatest for the slow units. Similarly, when activating MUs were stimulated together, the relationships between frequency and the initial rate of tension rise were linear. When the relationships were expressed in terms of relative tension rate the organs were found to be most strongly activated by the IIb muscle fibres, the responsiveness at the level of the whole muscle being reduced by unloading effects. The later component of the response showed an exponential relationship between discharge frequency and rate of tension development, the slope of the relationship between frequency and the logarithm of tension rate being independent of MU size. Although absolute tension increases during a contraction, this did not appear to impinge on the response which was dominated by the dynamic parameters of the contraction.

Failure of cefotaxime treatment in two children with meningitis caused by highly penicillin-resistant Streptococcus pneumoniae

Two infants, aged 8.5 and 11 months, were admitted for meningitis caused by Streptococcus pneumoniae. Failure of cefotaxime led to the identification of highly penicillin-G-resistant strains. Minimum inhibitory concentrations (MICs) for penicillin were > 2 micrograms/ml, and cefotaxime MICs were 2 micrograms/ml. Both patients rapidly responded to a combination of i.v. imipenem and rifampicin. It is now mandatory to test in-vitro susceptibilities of Streptococcus pneumoniae to penicillin G and other beta-lactam agents when meningitis is diagnosed in infants.

[Extraction of intravascular foreign bodies]

OBJECTIVE

Loss or displacement of foreign material within the cardiovascular system is not an uncommon event. Foreign bodies include fragments of diagnosis equipment, ruptured catheters or malpositioned or displaced intravascular prostheses. The incidence has increased with the development of endovascular catheterism and raises the problem of extraction.

METHODS

We report our experience with percutaneous extraction of intravascular foreign bodies.

RESULTS

There were 56 cases. Percutaneous extraction was successful in 53. In 11 cases, the procedure was carried out during a catheterism procedure and in the others the initial event had occurred earlier. The delay to extraction varied from a few hours to several years.

CONCLUSION

Percutaneous extraction of intravascular foreign bodies should be attempted before surgical removal, an often difficult high-risk procedure. The literature does not provide data on the frequency of intravascular foreign bodies.

[Right posterolateral thoracotomy in the treatment of of simple and isolated lesions of the heart]

The right posterolateral thoracotomy approach was used in 13 young girls aged from 1 to 8 years for open heart repair of atrial septal defect (ostium secundum and primum) and ventricular septal defect, without morbidity nor mortality. Neither the thoracotomy scar nor impaired growth of the mammary gland were visible. This approach is considered as safe as median sternotomy for open heart repair of isolated and simple cardiac defects, in prepuberty young females.

[Respective indications of enteral or parenteral nutrition during pre- and post-operative periods]

Denutrition is often associated with poor postoperative outcome. However, a large body of evidence, from studies comparing perioperative parenteral (PN) or enteral (EN) nutrition to the absence of perioperative nutrition, suggests that perioperative nutritional support provides significant improvements in both nutritional status and postoperative clinical outcome in selected patients who are or will become malnourished. The aim of this study was to select and review all relevant articles comparing perioperative parenteral and enteral nutritional support, either in terms of clinical outcome, or risks and costs, or in pathophysiological terms. Twelve clinical reports were reviewed. All contained methodological flaws, mainly type II statistical error due to an insufficient number of patients, inaccurate primary diagnosis, absence of blinding, and lack of objective criteria of judgement. These concerns warrant caution in interpreting the results. Moderately strong (grade B) recommendations can only be drawn from these studies: PN (compared to early EN) is associated with a higher rate of sepsis in patients following abdominal trauma; EN is as efficient as PN in patients following surgery; EN is safe and cheaper than PN. PN formulae lack many important nutrients (glutamine, arginine, cysteine, peptides, fibers, n-3 polyunsaturated fatty acids, and nucleotides). Many experimental (animal) and some clinical (in non surgical patients) studies showed that PN (compared to EN) induces gut mucosal atrophy, liver dysfunction, gut bacterial translocation and immune dysfunction. The final aim of PN and EN would therefore strikingly differ. The qualitatively imperfect PN would only supply the fasting patient with quantitative amounts of calories and proteins. Due to initially limited digestive tolerance, EN provides less nutrition than PN does, but would finally lead to the same or even better outcome, due to its ability to counteract stress induced gut and immune dysfunction. Current evidence therefore suggests that early EN is superior to PN in trauma patients, and not different from but cheaper (and therefore more cost-effective) than PN in surgical patients. Further controlled, randomised, and blinded studies including sufficient sizes of groups are required, especially in the surgical setting, to address a large number of still unanswered questions.

Seeding of YACs over regions 1q41-q42.3 and 11q14.3-q23 with microdissection clones

We describe the use of pooled, region-specific hybridisation probes to screen high-density replica filters of a human genome YAC library. The probes were derived by microdissection of an approximately 30-Mbp region subtending the translocation breakpoint on a der(1)(1;11)(q42.1;q14.3) chromosome. Of 70 microdissection clones used in pools of 4-10, 47 identified a total of 77 YAC recombinants, representing over 50% of the microdissected region. This strategy can easily be adapted to other poorly mapped subchromosomal regions of the human or other mammalian genomes and will provide a solid framework for detailed contig map constructions.

Influence of antibiotics and food intake on liver glutathione and cytochrome P-450 in septic rats

Experimental sepsis in rats induces a restriction in spontaneous food intake and a drop in liver glutathione, cytochrome P-450 (P-450) and aminopyrine demethylase (AD) activity. The present study was designed to assess the effects of antibiotics alone or when combined with food deprivation on these variables. Eighty-nine male Sprague-Dawley rats were assigned to six groups: control (C), acute infection (experimental pyelonephritis, I), acute infection with antibiotics and food given ad lib. (IA), control with antibiotics (CA), acute infection with antibiotics pair-fed to I (IAR), and sham-operated pair-fed to I (SR). Liver glutathione, P-450 and AD activities were reduced by 45.2, 79.8 and 41.2% respectively in group I. Glutathione and AD significantly increased only in those infected rats given antibiotics and allowed free access to food. P-450 did not normalize within the study period in infected rats receiving antibiotics and food repletion. The risk of drug hepatotoxicity in acute septic states is therefore closely related to the nutritional status. From this point of view, nutritional support is almost as important as treatment of infection.

Static sensitivity of tendon organs to tetanic contraction of in-series motor units in feline peroneus tertius muscle

1. The results of several studies have indicated an absence of any consistent relationship between the discharge of Ib Golgi tendon organ afferents and the steady-state tetanic tension generated by activating motor units. This question has been re-examined by recording the responses of individual tendon organs to tetanic, isometric contractions of one or more motor units from the peroneus tertius muscle of anaesthetized cats. 2. In three experiments, seventy-three individual tendon organ-motor unit interactions were recorded. The motor units were stimulated at 30-150 s-1 and for each tendon organ-motor unit pair a linear relationship was found between steady-state tetanic tension and Ib afferent discharge. The slopes of these relationships (the static sensitivities) were steepest for the weakest units. 3. When motor units were stimulated in combination, the relationship between discharge frequency and plateau tension was again linear but the static sensitivities were generally much lower than for single units and approached 1 impulse s-1 g-1. 4. Expression of these relationships in terms of the relative tensions generated revealed that the tendon organs were activated most strongly by the IIb muscle fibres, the static sensitivities being reduced by unloading effects. 5. The linear relationships observed during stimulation of single, and groups of, motor units suggest that the patterns of discharge from the tendon organs can mirror the steady-state contractile tensions within the muscle.

Pulmonary circulation evaluation before cavopulmonary connections: the cavopulmonary bypass

The outcome of Fontan-type procedures is dependent on several risk factors, among which pulmonary vascular resistances (PVRs) are an important component. Preoperative calculation of PVR entails several potential sources of error, particularly in patients with pulmonary atresia or multiple sources of pulmonary blood flow. In an attempt to develop a reliable test that accurately assesses the hemodynamic patterns of the pulmonary vascular bed before a Fontan procedure, a simulation of Fontan-type circulation was achieved in 13 patients by a partial cardiopulmonary bypass between the main pulmonary artery and both venae cavae (cavopulmonary bypass). During cavopulmonary bypass, pressures and resistances were recorded. Immediately after cavopulmonary bypass, the circulation was converted to standard cardiopulmonary bypass and the cavopulmonary connection was carried out. Preoperative pulmonary vascular resistance indexes were assessed roughly by the arteriovenous oxygen difference in systemic and pulmonary beds. There was no correlation between preoperative and perioperative calculations of pulmonary vascular resistance indexes (r = 0.24; p = not significant). Hemodynamic data available for all patients then were correlated to the early postoperative outcome assessed by a subjective four-point scale. A positive, significant correlation was found with intraoperative PVR (r = 0.90; p < 0.001), indexed PVR (r = 0.90; p < 0.001), and the pulmonary to systemic vascular resistance ratio (r = 0.98; p < 0.0001). Two of 13 patients had a 4-mm fenestration in the atrial baffle. No mortality or morbidity was related to the procedure. The absolute values of PVR and pulmonary vascular resistance indexes were strikingly higher than generally admitted for this type of procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary and secondary afferent discharges from the same spindle during chain fibre contraction in cat tenuissimus muscle

Pairs of Ia and II afferent fibres supplying primary and secondary endings lying in the same tenuissimus spindles were prepared in barbiturate anaesthetized cats in order to compare the variability in the rhythm of discharge of the two endings during responses elicited by the contraction of different intrafusal muscle fibres, especially by chain fibres. In these spindles, the intrafusal muscle fibres supplied by single static gamma-axons were identified with a recently developed technique based on the types of primary ending activation observed during gamma stimulation at 30 and 100 stimuli/s. The responses of the secondary endings to contraction of chain fibres either alone or with bag2 fibres were smaller and much more regular than the responses of the primary endings lying in the same spindles. This difference is probably related to the position of secondary endings along the intrafusal muscle fibres and to the mechanical properties of the muscle fibre regions on which the terminals lie. The dynamic properties of the encoding site of primary afferent impulses probably contribute to the difference. The different degrees of variability observed among secondary ending responses elicited either by chain fibres alone or by chain and bag2 fibres are not related to the type of activated intrafusal muscle fibres.