Conventional and dedifferentiated parosteal osteosarcoma. Diagnosis, treatment, and outcome

BACKGROUND

Dedifferentiated parosteal osteosarcoma (dd-POS) designates high grade transformation, of conventional low grade parosteal osteosarcoma (c-POS). The paradigm of preoperative diagnosis, neoadjuvant chemotherapy, and wide local excision has not been adequately evaluated for dd-POS, as it has been for conventional high grade intramedullary osteosarcoma.

METHODS

A retrospective review was conducted of 28 patients treated at the authors' institution between January 1980 and December 1992 for an osteosarcoma arising on the surface of the bone diagnosed as either c-POS or dd-POS. The clinicopathologic features, diagnosis, treatment, and patient outcome were analyzed.

RESULTS

A dedifferentiated component was identified in 12 of 28 tumors (43%). Neither the presence of radiolucencies (77% in c-POS and 100% in dd-POS, P = 0.06) nor medullary invasion (42% in c-POS and 50% in dd-POS, P = 0.28) distinguished dd-POS from c-POS. However, all patients who presented with focal hypervascularity on an arteriogram defined the high grade component of dd-POS that was confirmed by selective needle biopsy. This differed significantly (P = 0.00003) from c-POS. None of the patients with c-POS died of the disease (median survival duration, 77 months; range, 16-152 months). Six patients (35%) developed a local recurrence, but five were treated successfully with further surgery. In the dd-POS group, 7 of the 12 patients died of the disease. Ten patients with dd-POS received preoperative chemotherapy (IA cis-diamminedichloroplatinum, IV doxorubicin), and a good response (> 90% necrosis of high grade component) was observed in four. Among patients whose disease was localized, continuous disease free survival was prolonged significantly (P = 0.03) in patients with a good response (median, 75 months) compared with those who responded poorly (median, 13 months). Five patients remained continuously disease free (median, 66 months, range, 29-95 months).

CONCLUSIONS

Wide surgical excision alone is adequate treatment for patients with c-POS. Recognition of dedifferentiated areas with angiography and percutaneous biopsy of hypervascular areas should prompt the administration of chemotherapy and wide local excision to optimize patient outcome.

Modulation of cyclin transcript levels in cultured cells of Arabidopsis thaliana

Previous studies on the cell cycle of Arabidopsis thaliana have been hindered by the lack of synchronous cell culture systems. We have used liquid callus cultures and a cycloheximide-synchronized suspension culture of Arabidopsis to investigate changes in cyclin transcript levels in response to exogenous auxin, cytokinin, and nutrients, and during the cell cycle. CYCD1 (delta 1) transcript was virtually undetectable in liquid-cultured callus or suspension-culture cells. CYCD2 (delta 2) transcript levels were largely unaffected by the readdition of phytohormones or nitrate to the growth medium, and remained constant throughout the cell cycle in suspension-culture cells. CYCD3 (delta 3) transcript levels were strongly dependent on nitrate, and were induced at the G1/S transition following phytohormone readdition. In synchronized suspension-culture cells, CYCD3 transcript accumulated during the S phase, and remained constant thereafter. These results support the hypothesis that D cyclins function as part of the cellular machinery that integrates diverse signals impinging upon commitment to cell division. In synchronized cells transcripts of the mitotic cyclins CYC1, CYC2, and CYC3 reached a maximum with peak mitotic index, but CYC3 transcript levels increased earlier than those of CYC1 or CYC2. The kinetics of accumulation of CYC transcript levels support their classification as A-type (CYC3) and B-type (CYC1 and CYC2) cyclins, respectively.

Early physiologic patterns in acute illness and accidents: toward a concept of circulatory dysfunction and shock based on invasive and noninvasive hemodynamic monitoring

The aim of the present study was to explore methods, concepts, and techniques that provide recognition of circulatory deficiencies at the earliest possible time in the patient's illness. We used both the standard invasive pulmonary artery thermodilution catheter and noninvasive hemodynamic monitoring systems consisting of a new bioimpedance cardiac output device, pulse oximetry, transcutaneous oxygen (PtCO2) and carbon dioxide tensions as well as the transcutaneous oxygen tension/fraction of inspired oxygen ratio (PtCO2/FIO2). These three noninvasive systems were used to evaluate cardiac function, pulmonary function, and tissue perfusion, respectively. This approach to early noninvasive monitoring is based on recent evidence suggesting that poor tissue perfusion and oxygenation initiate circulatory dysfunction that leads to shock and organ failure. We studied 303 acute episodes of circulatory dysfunction and shock in 261 patients in a university-run county hospital; 75 were acute traumatic injuries and 109 acute nontrauma medical emergencies on admission to the emergency department, and 77 ICU patients with an acute illness or exacerbation of their current illness. The study was a prospective, descriptive study to identify early abnormal circulatory patterns reflecting the cardiac, pulmonary, and perfusion functions associated with death and with survival. We described noninvasively monitored patterns in individual illustrative cases, in common etiologic groups, and in physiologic categories representing various abnormal functional patterns. We found that hypotensive shock usually was preceded by episodes of high flow followed by low flow and inadequate tissue perfusion indicated by reduced PtCO2; this frequent pattern was modified by associated co-morbid conditions, especially hypovolemia, limited cardiac reserve capacity, age, hypertensive states, and increased body metabolism from infection, trauma, stress, exercise, temperature, and endocrine disorders. Reduced pulmonary function occurred in 18% of emergency patients; these were usually patients with thoracic trauma, severe hypovolemia, head injuries, chronic obstructive pulmonary disease, asthma, drug overdose, and central nervous system failure (massive stroke and coma). We concluded that noninvasive measurements identify early circulatory problems reliably and provide objective criteria for physiologic analysis as well as for definition of therapeutic goals and titration of therapy.

Improved thermostability of the North American firefly luciferase: saturation mutagenesis at position 354

We have used random chemical mutagenesis and a simple genetic screen to generate and isolate a thermostable mutant of luciferase from the North American firefly (Photinus pyralis). A single G-to-A transition mutation, resulting in the substitution of a glutamate for a lysine residue at position 354 in the protein sequence, was shown to be responsible for this enhanced thermostability. Replacement of Glu-354 with all possible amino acid residues was achieved using directed mutagenesis, and produced mutant enzymes with a range of thermostabilities. The mutations E354K and E354R conferred the largest increases in thermostability, suggesting that side-chain size and hydrophobicity, as well as charge, may also be important contributors to the overall thermostability of the polypeptide chain at this position. Unusually for such mutations, biochemical studies suggest that this position is on the surface of the protein and exposed to solvent.

Day case tonsillectomy in adults: how many are suitable?

Day case surgery is increasing to improve health care cost efficiency. The economic benefits of day surgery depend on how many patients are suitable. Adult tonsillectomy is a common operation. This study aims to define what proportion of adults undergoing tonsillectomy are suitable for day case surgery. One hundred consecutive adults undergoing elective in-patient tonsillectomy were studied prospectively. Patients were questioned, examined and investigated for any general medical or social contra-indications to day surgery as specified by the Royal College of Surgeons of England. They were also questioned about specific contra-indications to day case tonsillectomy, including NSAID contra-indications and tonsillectomy indicated for biopsy, quinsy or with another procedure. Seventy-six per cent patients satisfied the requirements. The most common reasons for failure were social. A high proportion of adults are suitable for day case tonsillectomy and therefore significant economic benefits are possible. However, prior to such surgery further work on operation suitability is required.

Chondrosarcoma of the pelvis. Prognostic factors for 67 patients treated with definitive surgery

BACKGROUND

Chondrosarcoma (CS) most commonly involves the pelvis. Local and systemic failures often result in poor outcome. Prognostic factors that determine patient outcome remain ill-defined.

METHODS

We retrospectively analyzed 67 patients with CS of the pelvis treated by definitive surgery from January 1970 to December 1992. All patients had localized disease including Grade 1 (19 patients), Grade 2 (18 patients), Grade 3 (17 patients), and dedifferentiated (13 patients) tumors. Thirty-two patients underwent a limb-sparing surgical resection and 35 patients underwent hemipelvectomy. Follow-up was available for all patients. The median duration of follow-up for the survivors was 115 months (range, 24-288 months).

RESULTS

At last follow-up, 52% of the patients were disease free, 8% were alive with disease, 36% died of disease, and 4% died of other causes. Nineteen patients (28%) had developed a local recurrence (LR). The median time to LR was 23 months (range, 1-111 months). Independent variables in a multivariate analysis associated with increased risk of LR included inadequate surgical margin, tumor epicenter in the pubis, and high grade histology. LR did not influence overall patient survival. Twenty-three patients (36%) developed distant metastases at a median time of 9 months (range, 1-111 months) postoperatively. Metastases developed in 0% of the patients with Grade 1, 20% of the patients with Grade 2 60% of the patients with Grade 3 and 75% of patients with dedifferentiated CS. On multivariate analysis, histologic high grade was the only significant predictive variable for distant relapse (P = 0.005).

CONCLUSIONS

The critical issue for a favorable outcome in low grade CS of the pelvis is adequate surgical excision (i.e., negative surgical margin). The high rate of systemic failure in high grade and dedifferentiated CS, despite adequate surgery, emphasizes the need for more effective systemic therapy.

The benevolent overreaction: nursing assessment and intervention in families coping with seizure disorder

Boone and Hartman identified the phenomenon of benevolent overreaction to describe the enmeshment seen in parents and their chronically ill children. The cylce of the benevolent overreaction begins with the child's diagnosis with a chronic illness and the subsequent natural protective behaviors of the parents. However, overprotection may become pathologic if these protective behaviors persist and delay or prevent the child's achieving developmental goals. This ego boundary deficit is one of the most frequently seen phenomena in families with chronically ill children. On the Comprehensive Epilepsy Unit this phenomenon was repeatedly observed. The purpose of this investigation was to ascertain the frequency of benevolent overreaction seen on the unit, and to identify the nursing interventions used to address this issue. A chart review was used to identify the frequency of the phenomenon during the past year, the discipline first identifying the phenomenon and nursing interventions applied to the phenomenon. Nursing staff interviews were then conducted, using unit census records of the past year, to identify staff recall of the phenomenon. Nursing staff frequently identified the components of benevolent overreaction in the inpatient population, however, consistent intervention for the phenomenon was less frequently seen. Autonomy, empowerment and self-advocacy for families are goals of the Comprehensive Epilepsy Unit. Consistent application of the nursing process to this phenomenon is vital to providing quality patient care.

Abrupt cessation of immunosuppression in a patient with persistent acute lymphoblastic leukaemia following allogeneic transplantation

A 20-year-old man with acute lymphoblastic leukaemia (ALL) in second complete remission underwent sibling donor transplant. Post-transplant there was haematological and immunophenotypic evidence of persisting disease. Cyclosporine was abruptly discontinued and following this the leukaemic clone disappeared. Discontinuation of immunosuppression may be of benefit in leukaemia which persists following transplant.

Treatment of facial synkinesis and facial asymmetry with botulinum toxin type A following facial nerve palsy

Facial synkinesis and asymmetry commonly impair the outcome of facial nerve palsy. Botulinum toxin type A is a neurotoxin which prevents acetylcholine release at the neuromuscular endplate, paralysing skeletal muscle. This paper examines its use in 24 patients with synkinesis and asymmetry affecting the eye and mouth. Sixty-eight of 72 treatments produced improved cosmesis. Dose-related complications occurred in 26 treatments but were generally mild and transient. The total dosages of toxin used were analysed. The higher dose group compared with the lower dose group had no significant advantage in overall cosmetic improvement but the complication rate was significantly higher in the higher dose group (20/39) compared with the lower dose group (6/33) (chi 2 6.675, P > 0.05).

Function of identified nerves in orientation to water flow in Tritonia diomedea

We determined which sensory and motor nerves mediate orientation to flow in the marine slug Tritonia diomedea, and tested the hypothesis that the slug orients to water flow by comparing the intensities of water flow stimulation on each side of its body. Lesion experiments revealed which nerves carried information necessary for flow orientation. The lateral branches of Cerebral Nerve #2 were the only cerebral nerves necessary for flow orientation. Cutting all cerebral nerves except the lateral branches of Cerebral Nerve #2 did not eliminate flow orientation. Thus, the lateral branches of Cerebral Nerve #2 were both necessary and sufficient (among the cerebral nerves) for flow orientation. Denervation of one side of the head by cutting Cerebral Nerves #1-4 on one side did not eliminate normal flow orientation. We have revised our model of how Tritonia diomedea orients to flow to allow for this unilateral determination of flow direction. Unilaterally cutting Pedal Nerve #3, which contains many pedal motor axons, reduced turning toward that side, but did not affect final orientation to flow. The ability to detect flow direction was not compromised by the inability to initially turn towards flow.

Antioxidant enzymes in intramural nerves of the opossum esophagus

Superoxide radical (O2-.) combines with nitric oxide (NO) to form peroxynitrite, thereby nullifying the biological activity of NO. Superoxide dismutase (SOD) prevents this reaction by converting O2-. to H2O2. We tested the hypotheses that the antioxidant enzymes catalase (CAT), Mn SOD, and Cu/Zn SOD are present in enteric neurons of the opossum esophagus, and that O2-. alters esophageal motor function. Immunostaining demonstrated CAT, Mn SOD, and Cu/Zn SOD immunoreactivity in interganglionic nerve bundles and ganglia of the myenteric and submucosal plexuses. Western blot analysis confirmed the presence of these enzymes in homogenates of esophageal muscularis propria, and enzyme assays demonstrated Cu/Zn SOD and Mn SOD activities of 262 and 73 U/mg protein, respectively. Both diethyldithiocarbamic acid, an inhibitor of Cu/Zn SOD, and xanthine (X) with xanthine oxidase (XO), which generate O2-., shortened the latency of the nerve-mediated contraction of circular esophageal muscle, the off response, by 20.2 and 23.4%, respectively. SOD alone did not affect the latency, but it inhibited the effect of X with XO on the latency. Antioxidant enzymes found in intramural esophageal nerves may play a role in regulating NO-mediated neuromuscular communication in the esophagus.

Multiple cloning sites carrying loxP and FRT recognition sites for the Cre and Flp site-specific recombinases

Plasmids were constructed carrying the loxP and FRT recognition sites for the Cre and Flp site-specific recombinases, respectively, within multiple cloning sites. Vectors carrying single and tandemly repeated targets are available with various flanking restriction enzyme sites. In addition, a series of plasmids carrying both loxP and FRT sites is available. These vectors facilitate construction of target molecules for these site-specific recombinases which are becoming increasingly important tools for the in vivo manipulation of DNA.

Would day-case adult tonsillectomy be safe?

Day-case surgery is increasing to improve health care efficiency. Adult tonsillectomy is performed on an inpatient basis in the UK because of safety concerns regarding primary haemorrhage. This study aims to investigate the likely safety of day-case tonsillectomy in adults, by defining the incidence and timing of primary haemorrhage and therefore to establish a safe time period for same-day discharge. Prospectively recorded data on 2,157 adult tonsillectomies over a five-year period were reviewed. Serious primary haemorrhage was uncommon (0.8 per cent). The 95 per cent reference range of time to primary haemorrhage was within 0 to 6.8 hours of surgery and the 95 per cent confidence interval (C.I.) of its upper limit was 5.2 to 8.4 hours. The results compare favourably with the UK inpatient and US adult day-case literature. We conclude that day-case tonsillectomy would probably be safe in adults if the patients are discharged after 8.4 hours.

Effect of nitroblue tetrazolium on NO synthase and motor function of opossum esophagus

Nitric oxide mediates neuromuscular events in the opossum esophagus. The NADPH diaphorase stain is used to localize nitric oxide synthase-containing enteric neurons. Cells stain by the NADPH diaphorase technique because they reduce nitroblue tetrazolium to the visible formazan. The effects of nitroblue tetrazolium on neuromuscular function and nitric oxide synthase of esophageal muscle were studied. The NADPH diaphorase stain was performed. Nitroblue tetrazolium inhibited lower esophageal sphincter relaxation, abolished the latency gradient of the off response, and inhibited nitric oxide synthase. The NADPH diaphorase technique stained myenteric plexus nerve cell bodies and nerve processes. Nitroblue tetrazolium is not a nonspecific muscle or nerve toxin, as nerve-mediated cholinergic responses, responses to exogenous nitric oxide, and responses to myogenic stimulation were maintained after nitroblue tetrazolium abolished the off response and lower esophageal sphincter relaxation. Nitroblue tetrazolium inhibits nitric oxide-mediated events and nitric oxide synthase. It stains neurons in the esophageal myenteric plexus.

The effects of recombinant human hemoglobin on esophageal motor functions in humans

BACKGROUND & AIMS

Nitric oxide controls lower esophageal sphincter (LES) relaxation and esophageal peristalsis in opossums, but its role in the control of esophageal motility in humans is not defined. Hemoglobin inactivates NO by binding it. Recombinant human hemoglobin (rHb1.1) was used to test the hypothesis that NO mediates esophageal motor functions in humans.

METHODS

rHb1.1 or human serum albumin was administered intravenously to fasting male volunteers. Esophageal manometric studies were performed before, during, and up to 6 hours after the infusion.

RESULTS

rHb1.1 increased the velocities of peristaltic contractions to produce simultaneous contractions in 6 of 9 subjects. It increased the amplitude and duration of contractile waves in the esophagus. There was no consistent effect on the resting tone of the LES, but LES relaxation was inhibited. Spontaneous, simultaneous high-pressure contractions occurred in 8 of 9 subjects. Lower retrosternal chest pain during swallowing was observed in 4 subjects.

CONCLUSIONS

rHb1.1 interfered with esophageal peristalsis and LES relaxation. It precipitated esophageal spasm in some subjects. These data support the hypothesis that the timing of smooth muscle esophageal peristalsis and LES relaxation are mediated by NO. They suggest that some disorders of esophageal motor function may result from defects in NO neuromuscular communication.

Nitric oxide modulates a calcium-activated potassium current in muscle cells from opossum esophagus

Nitric oxide mediates nerve-induced hyperpolarization of circular smooth muscle of the esophagus. Two mechanisms are proposed to explain this hyperpolarization: an increase in K+ current or a decrease in Cl- current. These studies test the hypothesis that nitric oxide increases a K+ current in esophageal smooth muscle. Three outward K+ currents are present in circular smooth muscle cells from the opossum esophagus. One current is a Ca(2+)-activated K+ current (IKCa2+). This current is inhibited by charybdotoxin. Whole cell currents were recorded from isolated opossum esophageal smooth muscle cells using the whole cell patch-clamp technique. These studies showed that IKCa2+ is activated at potentials more positive than -30 mV. Bath application of S-nitroso-L-cysteine increased IKCa2+ by 50% above control levels throughout the entire activation range of potentials. The enhanced current was reversible on washout. Either charybdotoxin, an inhibitor of IKCa2+, or (R)-p-8-(4-chloropenylthio)-guanosine 3',5'-cyclic monophosphorothioate, an inhibitor of protein kinase G, antagonized the increase in outward current induced by S-nitroso-L-cysteine. These data suggest that nitric oxide activates IKCa2+ via the guanosine 3',5'-cyclic monophosphate-protein kinase G signal transduction pathway.

Re-innervation of facial nerve territory using a composite hypoglossal nerve--muscle autograft--facial nerve bridge. An experimental model in sheep

The hypoglossal nerve has been used both entirely and in part to repair the facial nerve. Using the partial technique it may be difficult to obtain sufficient length and a free interposed graft is then required to extend the hypoglossal element. In six sheep the facial nerve was excised between its emergence from the stylomastoid foramen and its bifurcation in the parotid gland. The hypoglossal nerve was exposed and split longitudinally producing a limb which was reflected towards the distal stump of the facial nerve. This left a gap of 4-5 cm which was bridged with a freeze-thawed coaxially aligned skeletal muscle autograft. The sheep were examined at 8 months. Laser doppler blood-flow studies showed the blood-flow distal to the graft to be about 25% of that at an equivalent site on the normal side. Peak nerve conduction velocities were also reduced on the repaired side but stimulation of the proximal hypoglossal nerve was nevertheless capable of causing adequate contraction of both facial and tongue muscles. Histological comparison of the repaired facial nerves with equivalent sites on the normal side showed a reduction in mean axon and fibre diameters with normal myelin sheath thickness for the regenerated axon sizes. All of these features are to be expected in a regenerated nerve and are consistent with a good level of recovery of function.

A family of cyclin D homologs from plants differentially controlled by growth regulators and containing the conserved retinoblastoma protein interaction motif

A new family of three related cyclins has been identified in Arabidopsis by complementation of a yeast strain deficient in G1 cyclins. Individual members show tissue-specific expression and are conserved in other plant species. They form a distinctive group of plant cyclins, which we named delta-type cyclins to indicate their similarities with mammalian D-type cyclins. The sequence relationships between delta and D cyclins include the N-terminal sequence LXCXE. This motif was originally identified in certain viral oncoproteins and is strongly implicated in binding to the retinoblastoma protein pRb. By analogy to mammalian cyclin D, these plant homologs may mediate growth and phytohormonal signals into the plant cell cycle. In support of this hypothesis, we show that, on restimulation of suspension-cultured cells, cyclin delta 3 is rapidly induced by the plant growth regulator cytokinin and cyclin delta 2 is induced by carbon source.