Impaction of cancellous bone grafts impairs osteoconduction in titanium chambers

The method of using morselized compacted cancellous allografts for hip arthroplasty revision shows results that seem to differ dramatically from other kinds of allografting. In structural cancellous allografts, bone ingrowth usually is limited to 2 to 3 mm, whereas morselized compacted grafts seem to be remodeled totally in several cases, as judged by radiography. In the current study, impacted cancellous allografts were compared with unimpacted allografts. Seventeen rats had a bone conduction chamber implanted in the tibias bilaterally. On one side the chambers contained an impacted graft (bone volume fraction 65%) and on the contralateral side an unimpacted graft (bone volume fraction 35%). Impaction of the grafts was done preoperatively with a pressure of either 25 or 2500 MPa. Ingrowing bone could enter the cylindrical interior of the chamber only at one end. After 6 weeks the mean distance the ingrown bone had reached into the graft was measured on histologic slides. With both impaction pressures, the bone ingrowth distance was decreased to 30% of the unimpacted controls. It appears that impaction alone does not have a favorable effect on the osteoconductive properties of a bone graft. On the contrary, impaction seems to disfavor osteoconduction. However, in the clinical situation this is not necessarily a disadvantage.     

Histological integration of allogeneic cancellous bone tissue treated by supercritical CO2 implanted in sheep bones

Different chemical or physical methods of bone processing have been developed to decrease the antigenicity of allogeneic bone which may delay or prevent graft integration. We have developed a method based on delipidation and deproteination of the bone with a supercritical fluid and hydrogen peroxide. Cylinders of cancellous allogeneic bone treated in this way were implanted for four weeks, four months or eight months in holes drilled in sheep condyles or tibial plateau. Histological sections were then processed and analysed qualitatively and quantitatively using an image analysis software coupled to a light microscope. Measurements were made of the trabecular bone surface (BS/TS), the relative osteoid surface (OS/BS), the active osteoid surface (OS/BS), active resorption surface (Oc.S/BS) and the relative surface of newly formed bone. After four weeks, the control cylinders (non-treated allogeneic bone) had been invaded by cellular tissue composed of lymphocytes and plasmocytes surrounding remnants of the donor bone marrow tissue. The processed cylinders showed osteoid apposition at the surface of their external trabeculae. The trabecular bone and osteoid surfaces were significantly higher in the processed bone sections than in the control bone sections. After four months, most of the control material had been osteolysed and replaced by connective tissue containing lymphocyte islets, while the processed materials showed a large amount of bone synthesized at the surface of implant trabeculae which appeared fragmented and disseminated within the newly formed bone. All the histomorphometric parameters measured were significantly different from those of the control. By eight months, most of the control material had been totally osteolysed with very little bone ingrown in the implantation site. Only one control implant had been integrated. The processed cylinders were difficult to discern from the bone in which they were implanted. The parameters measured on the processed cylinders were significantly higher than those measured on the control sections. IN CONCLUSION: the treatment applied to the bone enhanced allogeneic bone integration and could provide a new kind of tissue treatment for bone banking.     

A comparative analysis of subchondral replacement with polymethylmethacrylate or autogenous bone grafts in dogs

A comparative analysis was made of subchondral replacement with polymethylmethacrylate and autogeneic bone grafts in defects in the medial femoral condyles of dogs. The defect produced a 50% reduction in subchondral stiffness. An in vitro preparation helped establish that subchondral stiffness returned to normal after reconstruction with polymethylmethacrylate. The in vivo model demonstrated a reduction in subchondral stiffness in both groups at three weeks, but the bone grafted side returned to normal and the methylmethacrylate side recovered to 79% of the control at 12 weeks. There were no deleterious effects on the articular cartilage in either group when analyzed histologically and biochemically. A marked increase in new bone formation and subchondral porosity was found in the polymethylmethacrylate groups. This study supports the clinical use of subchondral polymethylmethacrylate after the exteriorization and curettage of benign bone tumors such as giant cell tumors.     

Effect of allogeneic, freeze-dried, demineralized bone matrix on guided bone regeneration in supra-alveolar peri-implant defects in dogs

This randomized, split-mouth design study evaluated the adjunctive effect of allogeneic, freeze-dried, demineralized bone matrix on guided bone regeneration in a critical-size, supra-alveolar, peri-implant defect model. Contralateral supra-alveolar peri-implant defects, 5 mm in height, each including two titanium implants, were surgically created in five beagle dogs. Demineralized bone matrix in autologous blood was placed over the implants in one randomly selected mandibular jaw quadrant. A space-making expanded-polytetrafluoroethylene membrane was used to provide guided bone regeneration bilaterally. Following a 16-week healing interval, tissue blocks were harvested and prepared for histometric analysis. Differences between experimental conditions (guided bone regeneration sites with and without demineralized bone) were evaluated using paired t tests (n = 4). Demineralized bone particles were discernible, with limited signs of resorption. The bone matrix particles appeared to be solidified within a dense connective tissue matrix and in close contact with the implants. Limited matrix remineralization was apparent adjacent to the alveolar crest. No statistically significant differences were found between experimental conditions for any parameter examined. Peri-implant defect height averaged 5.0 +/- 0.2 mm and 4.9 +/- 0.4 mm, vertical bone regeneration 1.5 +/- 0.9 mm and 1.1 +/- 0.4 mm, osseointegration within the extent of the defect 10.0 +/- 3.9% and 15.3 +/- 5.3%, osseointegration within the extent of regenerated bone 30.4 +/- 13.7% and 52.1 +/- 17.9%, and osseointegration within the alveolar base 68.8 +/- 13.1% and 74.4 +/- 7.1% for guided bone sites with and without demineralized bone, respectively (P > .05). The results suggest that freeze-dried demineralized bone has no adjunctive effect on guided bone regeneration in supra-alveolar peri-implant defects, that guided bone regeneration has a limited potential to enhance alveolar regeneration in this defect model, and that a 16-week healing interval appears insufficient for turnover and maturation of demineralized bone under provisions for guided bone regeneration.     

Estrogen and cancellous bone loss in the fowl

Long-term follow-up study with positron emission tomography (PET) has been conducted in a patient with superficial siderosis for ten years. A 63-year-old right-handed woman began to exhibit a cerebellar ataxia when she was 52 years old. Thereafter she has been exhibiting a slowly progressive course of pyramidal signs, hearing loss, anosmia, bilateral sciatica and memory disturbance in addition to the cerebellar ataxia. Series of x-ray CT and MRI disclosed a progressive atrophy of the cerebellum, specifically in the superior vermis, and a mild diffuse atrophy in the cerebral hemispheres, whereas no significant atrophy was seen in the brainstem. A marked hypointensity was seen along the rim of the brain structures including brainstem, cerebellum, sylvian fissures and the medial temporal lobes on MR T 2-weighted images. This hypointensity was also found at the edges of the third and fourth ventricles. These findings were regarded as haemosiderin deposit. By using oxygen-15, PET was carried out repeatedly with ten-year interval. In the initial PET study, both cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were mildly decreased in the cerebellar hemispheres and the occipital cortices. The follow-up PET study revealed a progressive reduction of CMRO2 in the brainstem, cerebellar hemispheres and temporal cortices including the hippocampus in which the haemosiderin deposition was marked on MRI, whereas the reduction of CBF was not advanced as compared with CMRO2. It was suggested that the progressive reduction of CMRO2 in the brain sites where the haemosiderin deposition was observed on MRI reflected the clinical course of neurological deterioration.     

Reconstruction of mandibular continuity defects in dogs using poly (L-lactide) mesh and autogenic particulate cancellous bone and marrow: preliminary report

PURPOSE: This study evaluated the reconstruction of continuity defects in the canine mandible using a poly [L-lactide] (PLLA) mesh tray and particulate cancellous bone and marrow (PCBM). MATERIALS AND METHODS: Eight adult dogs were divided into two groups of four dogs each. In group A, each dog had a tray fixed with stainless steel wires on each side of the mandibular stumps with the concave surface of the tray attached to the inferior border of the mandible (U-fixation). In group B, the concave surface was attached to the superior border (inverted U-fixation). Each tray was filled with PCBM from the ilium. After the operation, the dogs were radiographed, and specimens were examined histologically at 3-, 6-, and 12-month intervals. RESULTS: All of group A showed good clinical healing and the continuity of the mandibular bone was regained within 3 months postoperatively. However, fibrous tissue had invaded through the area above the tray, resulting in a poorly shaped alveolar ridges. In group B, the dogs showed good bony regeneration with well-shaped alveolar ridges. However, two animals in this group had partial exposure of the PLLA mesh tray into the oral cavity. CONCLUSION: It is suggested that a combination of the PLLA mesh and PCBM grafts might be a useful technique for functional reconstruction of the jaw bone, specifically using method A (U-fixation) as a technique to reconstruct continuity defects of the mandible, and method B (inverted, U-fixation) as a promising method for alveolar reconstruction to make wearing dentures possible.     

Visceral varicella-zoster after bone marrow transplantation: report of a case series and review of the literature

OBJECTIVE: To compare the efficacy and vaginal birth intervals after intravaginal or oral misoprostol for labor induction. METHODS: One hundred seventy-eight women were randomized to one of two double-blind groups: 1) oral misoprostol 200 microg and one-half tablet placebo intravaginal or 2) oral placebo tablet and one-half tablet of a 100-microg misoprostol intravaginal (dose 50 microg). Doses were repeated every 6 hours until labor was established (maximum of three doses). RESULTS: Ninety-three subjects were assigned to oral misoprostol and 85 to intravaginal administration. Oral administration was accompanied by significantly shorter intervals to the onset of uterine contractility (133+/-78 minutes versus 168+/-93, P < .01) but a higher incidence of abnormal uterine contractile activity (tachysystole 38.7% versus 20.0%, P < .01; hyperstimulation syndrome 44.1% versus 21.2%, P < .01). No adverse maternal or neonatal outcomes were noted, nor were there differences in cesarean delivery rates or total lengths of labor. CONCLUSION: Oral administration of 200 microg misoprostol has similar efficacy to intravaginal administration of 50 microg but is associated with more frequent abnormal uterine contractility.     

Brain cancer in petrochemical workers: a case series report

Eighteen primary brain cancer deaths among male workers at one Texas petrochemical plant from 1965-1980 are reported. Federal officials from OSHA and NIOSH are performing with company cooperation an historical prospective cohort mortality study, a case-control study, and neuropathological case confirmation. Average age at death was 53 (range 30-66). Median employment was 21 years and median latency was 24 years. 15/18 tumors were glioblastoma multiforme, an unusual histologic distribution. A preliminary estimate reveals a plant-wide excess brain cancer risk twice expected among 6,800 white males at the plant since 1941. Brain cancer mortality rates in surrounding counties are in the median range for US counties from 1950-1969. Ten recognized or suspected carcinogens are present in quantities greater than 10(6) lbs/yr. To date no common chemical exposures or work assignments have been identified among the cases. Data on 26 experimental brain carcinogens and relevant epidemiological studies are provided.     

The mini bottle brush--a new fastening device in cancellous bone

We examined the associations between cerebral infarction (CI), asymptomatic arteriosclerosis obliterans (ASO), and known risk factors for these diseases. The subjects were 67 elderly patients (11 men and 56 women, mean +/- SD age of 79.6 +/- 8.5 years). in 44 patients CI was diagnosed by CT scan; 23 were classified as having cortical infarction and 21 as having lacunar infarction. In 41 patients asymptomatic ASO was diagnosed by an ankle-pressure index (API) of less than 0.9. To identify risk factors for these diseases, we examined the association among these diseases and hypertension (blood pressure > or = 140/90 mmHg), hypercholesterolemia (total cholesterol concentration > or = 220 mg/dl), hypertriglyceridemia (triglyceride concentration > or = 150 mg/dl), low HDL-cholesterolemia (HDL-C concentration < 40 mg/dl), high LDL-cholesterolemia (LDL-C concentration > or = 150 mg/dl), and glucose intolerance (fasting blood sugar concentration > or = 110 mg/dl). The incidence of asymptomatic ASO in the subjects with CI was significantly higher than that in the subjects without CI (chi 2 test; p < 0.05, odds ratio 6.4), including cortical infarction (p < 0.05, odds ratio 8.9) and lacunar infarction (p < 0.05, odds ratio 3.8). Patients with lacunar infarction were more likely to have hypertension than were controls (p < 0.05). Cortical infarction was not associated with these risk factors. Both low HDL-C and high LDL-G were more common in patients with asymptomatic ASO than patients without asymptomatic ASO (p < 0.05). These results indicate that CI and asymptomatic ASO are strongly associated in the elderly, especially in subjects with cortical infarction, and that aging itself contributes to cortical infarction.     

Myasthenia gravis after allogeneic bone marrow transplantation. A case report and a review of the literature

PURPOSE: The treatment of infant acute lymphoblastic leukemia (ALL) continues to be a significant challenge for pediatric oncologists due to the high incidence of early relapses. Salvage regimens used to date have met limited success. We describe two cases of relapsed infant ALL who have achieved long-term survival with an intensive antimetabolite-based salvage regimen. PATIENTS AND METHODS: Two consecutive infants with relapsed ALL presented at our institution and were treated with an antimetabolite-based regimen. Both cases exhibited clinical and biological phenotypes previously associated with infantile ALL. RESULTS: Both patients have achieved prolonged and sustained remissions 48 and 30 months EFS respectively following therapy with intensive antimetabolite-based salvage regimen. CONCLUSIONS: An intensive multiagent antimetabolite based salvage regimen resulted in prolonged EFS in two cases of relapsed infant ALL. Dose intensification was achieved by administering repeated cycles of the same treatment schema using high dose chemotherapy throughout therapy. These infants were spared prophylactic cranial irradiation without a negative impact on outcome. The use of L-asparaginase, timed after high-dose Cytarabine (ARA-C) throughout therapy, might have contributed to their cure.     

Zolpidem (Ambien): a pediatric case series

BACKGROUND: In 1993, the nonbenzodiazepine sedative-hypnotic zolpidem tartrate (Ambien) was approved for use in the US. Zolpidem has an imidazopyridine structure and possesses a rapid onset of action and a short half-life. The toxic threshold and profile have not been well established in the pediatric population. METHODS: All pediatric zolpidem exposures reported to a regional poison information center over 24 months were reviewed retrospectively from the American Association of Poison Control Centers Toxic Exposure Surveillance System data collection forms. RESULTS: Twelve pediatric zolpidem exposures were reported. Seven were unintentional (ages 20 mon-5 y) and five were intentional misuse/suicide (ages 12-16 y). The regional poison information center was contacted within 1 h in ten cases with onset of symptoms within 10 to 60 min (mean 31.6 min). One child had no effect with 2.5 mg. As little as 5 mg caused symptoms with minor outcome in six unintentional ingestions (5-30 mg). Minor to moderate symptoms were reported 1-4 h after intentional ingestions (12.5-150 mg). The duration of symptoms in the unintentional cases ranged from less than 60 min up to 4 h (mean 2.4 h) and 6-10 h (mean 7.5 h) in the intentional exposures. Treatment consisted of observation (4), syrup of ipecac (1), lavage and activated charcoal (1), activated charcoal alone (5), and unknown (1). CONCLUSION: Due to the very rapid onset of central nervous system symptoms in children, emesis is not a treatment option. Supportive care, activated charcoal in large ingestions, and observation until symptoms resolve may be sufficient in most pediatric cases.     

Treatment of peri-implantitis using guided bone regeneration and bone grafts, alone or in combination, in beagle dogs. Part 1: Clinical findings and histologic observations

The purpose of this study was to evaluate and compare the treatment of ligature-induced peri-implantitis using guided bone regeneration and two bone grafts alone and in combination. Mandibular premolars and first molars were extracted from four beagle dogs and after 3 months of healing, three Br?nemark implants were placed on each side of the mandibles. Following abutment connection 3 months later, experimental peri-implantitis was induced by tying plaque-retentive ligatures around all abutments. Ligatures and abutments were removed after 3 months, and bony defects measured and treated with either: (1) debridement only; (2) debridement plus resorbable hydroxyapatite; (3) debridement plus canine freeze-dried demineralized bone; (4) debridement plus guided bone regeneration; (5) debridement plus resorbable hydroxyapatite and guided bone regeneration; or (6) debridement plus canine freeze-dried demineralized bone and guided bone regeneration. Pretreatment and 4-month-posttreatment comparison revealed a significant but variable degree of clinically appreciable hard tissue fill with all treatment procedures. Guided bone regeneration procedures resulted in the greatest fill, followed by bone grafts alone and flap debridement. There was no significant difference between guided bone regeneration and both guided bone regeneration/graft combinations; therefore, guided bone regeneration procedures appear to be a predictable treatment for plaque-induced peri-implant defects.     

Use of risperidone in pervasive developmental disorders: a case series

A series of 14 children and adolescents (ages 9-17 years, 10 males) were treated with risperidone for pervasive developmental disorder. The rationale for using an atypical neuroleptic agent is based on its ability to target both positive and negative symptoms of schizophrenia. It was postulated that symptoms similar to the positive and negative symptoms of schizophrenia may be observed in the pervasive developmental disorders and might respond favorably to risperidone. Twelve of the 14 youths had been treated previously with several psychotropic drugs, often concurrently. Risperidone was initiated at a starting dose of 0.25 mg twice daily and increased in 0.25 mg/day increments every 5-7 days. Optimal dosages ranged from 0.75 to 1.5 mg daily in divided doses. Thirteen of the 14 youths appeared to benefit from risperidone. Improvement in functionality on the Children's Global Assessment Scale was demonstrated in 13 of 14 cases. Disruptive behaviors, when present, markedly decreased on risperidone. Ten patients showed a marked reduction in agitation and anxiety. Social awareness improved markedly in 10 patients, moderately in 3, and only slightly in 1. All but 1 patient demonstrated a lessening in obsessional behaviors. Effects on attention were uniformly positive. Side effects were minimal at the dosages used in this study; 5 patients had initial sedation. Neither extrapyramidal side effects nor agitation was observed in any case. Ten of 14 youths could be managed with risperidone monotherapy. During the follow-up period (mean 7 months), none of the patients experienced a major relapse while taking risperidone. Positive and negative symptoms, as typically characterized in schizophrenia, were both found to improve equally well with risperidone treatment. Based on these findings, a prospective clinical trial with a randomized controlled design is warranted.     

Granulocytic sarcoma as isolated extramedullary relapse after donor lymphocyte infusion in a patient with CML who relapsed after allogeneic bone marrow transplantation: a case report

Nineteen patients with spina bifida and bilateral dislocation of the hips were studied with a minimal follow-up of 10 years. The average age at review was 21 years (range, 10-31). Ten patients had an upper neurologic level (thoracic to L3), and nine had a low lesion (L4 to sacrum). Three patients had no hip surgery. A closed or open reduction was performed in 12 hips, supplemented by one or more surgical procedures. Of these, 10 remained enlocated, and two had redislocated. In all other hips, several surgical procedures were performed, aimed at improvement of hip-flexion deformity or stability. At follow-up, one patient had occasional pain in one hip, which was dysplastic. Of the 10 patients with a high lesion, only two were walkers, but both had bilateral dislocation of the hips at follow-up. In contrast, all nine patients were walkers, but four of these had bilateral dislocation at follow-up. We found that a level pelvis and good range of motion of the hips are more important for ambulation than is reduction of bilateral hip dislocation.     

Multifocal bone tuberculosis: apropos of a case

OBJECTIVE: To review recent experience of gastroschisis at the Royal Children's Hospital, Melbourne. METHODOLOGY: Retrospective review of admissions over a 13 year period, June 1980-June 1993 inclusive, including an analysis of those factors influencing mortality, morbidity and complications. RESULTS: There were 49 infants, of whom two died (4%), both having an associated bowel atresia. Mode of delivery, age at operative repair, birthweight centile and silo repair had no significant effect on the duration of total parenteral nutrition (TPN) or hospital stay. The presence of short gut and/or gut resection and localized bowel narrowing or bowel atresia resulted in a significant increase in the duration of TPN and hospital stay. The presence of a central venous line was a highly significant risk factor for the development of systemic sepsis. CONCLUSION: Currently gastroschisis has a good outlook with a low mortality. Infants with short gut/resection and bowel atresia have a long duration of TPN and hospitalization, with significant morbidity and complications.     

Anaesthesia for lambs undergoing spinal surgery: a case series

The purpose of this study was to identify whether the central extracellular fluid volume status following hypo- and hypervolaemia can be measured by the initial distribution volume of glucose or by the extravascular lung water. These two estimates were compared with the initial distribution volume of sucrose which has been used as an indicator for the measurement of the extracellular fluid volume. The above three estimates were determined by the administration of glucose, chilled saline and sucrose solutions, before and after haemorrhage (30 mL kg-1), and subsequent fluid load (lactated Ringer's solution 90 mL kg-1). The distribution volumes of glucose and sucrose decreased after haemorrhage and increased after fluid load compared with normovolaemic values, and a linear correlation was obtained between these two distribution volumes (r = 0.93, P < 0.001, n = 36). However, the extravascular lung water remained statistically unchanged throughout the procedure, despite a weak linear correlation with the sucrose distribution volume (r = 0.38, n = 33, P < 0.05). These results indicate that the initial distribution volume of glucose is more useful as an indicator of the central extracellular fluid volume status than the extravascular lung water.     

Early neurologic complications following allogeneic bone marrow transplant for leukemia: a prospective study

BACKGROUND: Bone marrow transplant (BMT) is used for both neoplastic and nonneoplastic diseases. Following BMT, particularly during the first 3 months, patients have a number of neurologic complications. We evaluated the early neurologic complications following BMT and their influence on survival. METHODS: We prospectively followed 115 consecutive patients having BMT for leukemia, for a median period of 90 days after transplantation. RESULTS: Sixty-four patients (56%) had neurologic complications. Sixteen developed more than one complication. Twenty-seven patients (25%) had major neurologic complications: metabolic encephalopathy (8), seizures (8), psychiatric symptoms (3), cerebral hemorrhage (1), cerebral abscess (1), leukemic meningitis (1), peripheral neuropathies (5), and myopathies (2). Forty patients (35%) had minor complications, including headache (16) and tremor (31). Major neurologic complications occurred after engraftment in most patients. Metabolic encephalopathy correlated with graft-versus-host disease (GVHD) (p < 0.03). Seven percent of patients had generalized seizures that occurred without signs of structural cerebral lesions. Probability of survival at day 90 was lower in patients with than in those without major central nervous system complications (63% versus 87.5%, p < 0.01). CONCLUSIONS: Neurologic complications are frequent during the first 3 months following BMT and affect patient survival. Drug neurotoxicity and acute GVHD are the main factors influencing their occurrence.