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Biomedical subjects

J B Atkinson

Publications and source records attributed to J B Atkinson.

161 records · Page 9Linked to original sources
PubMed1981

Diagnostic value of the Hemalog D-90 in classifying acute childhood leukaemias.

Accurate classification of the acute leukaemias is dependent not only on morphological characteristics, but also on cytochemical staining properties of the blasts in peripheral blood and bone marrow. This study was undertaken to evaluate the Hemalog D-90, an automated cytochemistry system for white cell differential counts, as an adjunct to conventional microscopy in the classification of acute childhood leukaemias. Fifty-two patients were classified according to morphology and cytochemical reactions of the cells obtained from peripheral blood. In 29 with classical acute lymphoblastic leukaemia (ALL), the Hemalog D showed the lymphoblasts to be non-peroxidase staining and these were recorded mainly as lymphocytes. In contrast, the blasts of eight patients with acute myeloblastic leukaemia (AML) were peroxidase positive, being recorded as neutrophils. Of the remaining 15 patients, 10 were classified as "Probably ALL' because they lacked some of the morphological or cytochemical criteria for classical ALL, while five were unclassifiable. However, in all these 15 patients the Hemalog D results were similar to those obtained in patients with classical ALL. We concluded that the Hemalog D was a useful adjunct in distinguishing ALL from AML, including the morphologically indistinct types.

Acute Disease↗
PubMed1981

Myotonia congenita. A histochemical and ultrastructural study in the goat: comparison with abnormalities found in human myotonia dystrophica.

Muscle biopsy specimens from the myotonic goat, an animal model of heritable myotonia, were examined histochemically and by electron microscopy. After Periodic acid-Schiff (PAS) staining with diastase digestion, there was increased PAS-positive material within myotonic goat fibers, as compared with those of normal goats. Myotonic muscle stained with alizarin red S, a histochemical stain for calcium, also had an increased staining reaction when compared with muscle from normal goats. Several ultrastructural abnormalities were found in myotonic goat muscle using routine osmium and uranyl acetate staining. These included increased density of the t-tubules, electron-dense material within t-tubules, proliferation and dilatation of sarcotubular elements, and abnormal mitochondria in the myotonic biopsy specimens. To further study muscle ultrastructure, ruthenium red and lanthanum were used as electron microscopic stains with specificity for membranes. There was increased density of the sarcolemma and t-tubules in myotonic muscle stained with ruthenium red as compared to normal, and lanthanum produced a darker staining reaction of the myotonic goat sarcolemma. The histochemical and ultrastructural differences between normal and myotonic goat muscle were interpreted to be consistent with a morphologic basis for the abnormal contraction-relaxation properties characteristic of myotonia.

Adolescent↗
PubMed1980

Recurrent transient ischemic attacks after carotid endarterectomy.

The postoperative courses of 113 patients undergoing 121 carotid endarterectomies between 1974 and 1979 were analyzed for recurrent transient ischemic attacks (TIAs). The TIAs were the indication for the original operation in all patients; 31 patients had a stable neurologic deficit prior to operation. Two patients sustained major strokes and three had nondisabling minor strokes. Three patients had late strokes. Recurrent TIAs occurred during follow-up in 28 patients, and these were classified into four distinct categories: (1) Ten patients had single TIAs in the distribution of the carotid artery operated on in the early postoperative days. (2) Four patients had late, repetitive TIAs related to the operated side. (3) Five patients had late TIAs in the distribution of the contralateral artery. (4) Nine patients had single or multiple TIAs owing to recurrent vertebrobasilar insufficiency. Close, long-term follow-up of postendarterectomy patients is recommended to locate those who will have surgically correctable lesions.

Aged↗
PubMed1980

Electron paramagnetic resonance and saturation transfer electron paramagnetic resonance studies on erythrocytes from goats with and without heritable myotonia.

Erythrocytes from myotonic goats, an animal model of heritable myotonia, and normal goats were studied using electron paramagnetic resonance (EPR) and saturation transfer electron paramagnetic resonance (ST-EPR) spin labeling techniques. Three fatty acid spin labels with the nitroxide moiety at progressively greater distances from the carboxyl group were used to monitor different regions within the erythrocyte membrane. Since spin labels have been shown to induce hemolytic and morphologic alterations in erythrocytes, conditions for minimizing these alterations were first defined by hemolysis studies and scanning electron microscopy. Using these defined conditions for our studies we observed no significant differences in any of the EPR or ST-EPR parameters for normal and myotonic goat erythrocytes with any of the fatty acid spin labels used. Our results do not support the theory that myotonia is the result of a generalized membrane defect characterized by increased membrane fluidity as determined by fatty acid spin labels.

Animals↗
PubMed1979

Late results of extra-anatomic bypass.

Clinical progress and results were reviewed in 100 consecutive patients who underwent extra-anatomic bypass procedures for brachiocephalic and aortoiliac occlusive disease during the past 15 years. Of 113 procedures in this group, extra-anatomic bypass of the brachiocephalic vessels, axillo-femoral bypass, and femorofemoral bypass were performed. Although these procedures were performed in high-risk patients to avoid intrathoracic and intra-abdominal reconstruction or to circumvent undesirable anatomic areas, a low operative mortality was achieved. Symptomatic improvement, augmented Doppler ankle pressure index, and high limb-salvage rate were noted. Life-table analysis has confirmed prolonged five-year graft patency. The suspected high-risk characteristic in this group was corroborated by high progressive mortality observed particularly after axillo-femoral bypass and was due primarily to the severity of associated diseases. Analysis of the late results of extraanatomic bypass confirms the safety and effectiveness of this procedure in poor-risk patients.

Adult↗
PubMed1979

The composition and calcium transport activity of the sarcoplasmic reticulum from goats with and without heritable myotonia.

Studies were conducted on purified sarcoplasmic reticulum isolated from myotonic goats, an animal model of heritable myotonia. When compared to sarcoplasmic reticulum from normal goats, fragmented sarcoplasmic reticulum from the myotonic goat had (1) increased levels of calcium, (2) increased rates of calcium uptake and efflux, (3) an increased sialic acid content, and (4) an increased content of saturated fatty acids. These differences support the concept of a structural and functional defect as a basis for the abnormal contraction-relaxation characteristics of myotonia.

Animals↗
PubMedDate not supplied

Loss of blood group A in acute leukemia. Morphologic and biochemical studies of red cells.

A patient with blood type A had acute myelomonocytic leukemia; his red cells (RBCs) typed as O and his serum had anti-B. RBC membranes were isolated from the patient as well as from controls with group A and O red cells. The membranes were incubated with uridine diphosphate (UDP)-N-acetyl-D-14C galactosamine in plasma from the patient and controls with group A and O red cells. RBC membranes from the patient behaved normally in that they incorporated the terminal carbohydrate responsible for blood group A activity. Scanning electron microscopy showed that the patient's RBCs had striking morphologic changes, with marked crenation and numerous knisocytes and dacryocytes. It was concluded that loss of the A antigen in this patient was not due to an abnormality of the enzyme required to convert H substance to A substance. It was postulated that weakening of the A antigen in some patients with leukemia may be related to a steric modification associated with abnormal red cell morphology.

ABO Blood-Group System↗
PubMedDate not supplied

Comparison of intratracheal pulmonary ventilation with hybrid intratracheal pulmonary ventilation in a rabbit model of acute respiratory distress syndrome by saline lavage.

We compared different hybrid mode ITPV (h-ITPV) flow rates, and h-ITPV with intratracheal pulmonary ventilation (ITPV) with respect to CO2 clearance and oxygenation. Surfactant deficiency was induced in six adult rabbits with saline lavage. The study consisted of three phases. Phase 0: Stabilization on conventional mechanical ventilation (CMV). Phase I: Bias flow initiated at same pressure and respiratory rate as Phase 0. Flow rates of 25%, 50%, 75% h-ITPV, and ITPV were initiated. Animals were transitioned from CMV to 25% h-ITPV proceeding sequentially to ITPV or vice versa. Phase II: Animals were returned to CMV. Statistical analysis included the two-way analysis of variance (ANOVA) and repeated measures ANOVA with Tuckey's test. No difference in PaCO2 was observed among all h-ITPV flow rates or between h-ITPV and ITPV. After bias flow was introduced (transition from Phase 0 to Phase I), PaCO2 decreased by 37%. PaCO2 increased by 119% during Phase II. Oxygenation improved in all animals, particularly in those transitioned to 25% h-ITPV and proceeding to ITPV. No difference in CO2 clearance between ITPV and h-ITPV was observed. Even at low bias flows, excellent CO2 clearance was achieved. Oxygenation was superior when animals were transitioned from CMV to h-ITPV. Hybrid-ITPV offers some advantages over ITPV and may represent a powerful tool in the management of acute respiratory distress syndrome (ARDS).

Animals↗
PubMedDate not supplied

Metastatic sites in stage IV and IVS neuroblastoma correlate with age, tumor biology, and survival.

PURPOSE: The goal of this study was to determine the incidence of metastatic sites in neuroblastoma and the extent to which metastatic sites correlate with age, tumor biology, and survival. PATIENTS AND METHODS: All 648 patients with stage IV and IVS neuroblastoma registered on Children's Cancer Group protocols 3881 and 3891 were analyzed. Metastatic site data were provided by treating institutions and reviewed in patients with central nervous system (CNS), intracranial, lung, or "other" metastases. RESULTS: The incidence of metastatic sites at diagnosis was 70.5% in bone marrow, 55.7% in bone, 30.9% in lymph nodes, 29.6% in liver, 18.2% in intracranial and orbital sites, 3.3% in lung, and 0.6% in CNS. Event-free survival (EFS) was decreased in patients with bone, bone marrow, CNS, intracranial/ orbital, lung, and pleural metastases, and improved in those with liver and skin metastases. In infants, MYCN amplification and unfavorable Shimada histopathology correlated with increased frequencies of bone and intracranial or orbital metastases. In older patients, MYCN amplification correlated with increased frequencies of intracranial or orbital, liver, and lung metastases. Multivariate analysis revealed that metastatic site is not an independent prognostic factor. CONCLUSIONS: Metastatic pattern in neuroblastoma differs with age and correlates with tumor biological features and EFS. These correlations could reflect changes in host or tumor biological features with age resulting in differences in metastatic capacity or tumor affinity for specific sites.

Adolescent↗
PubMedDate not supplied

Partial peritoneal alimentation in an infant.

We provided partial peritoneal alimentation to a 1.69-kg 11-month-old premature infant who had no available central venous access, depleted peripheral venous access, and gastrointestinal dysfunction. A cuffed silastic catheter was surgically inserted into the suprahepatic space. An alimentation solution was continuously infused into the peritoneum for 28 days to supplement peripheral venous and nasogastric alimentation and contributed 42 +/- 15% of total calories daily. Weight gain was achieved, but complications included hypoglycemia, hypophosphatemia, intravascular dehydration, catheter site leakage, ascites, and hydrocele. At autopsy 11 months later, lipid accumulation was present in the upper peritoneum and the hilar regions of the lungs secondary to preexisting lymphatic obstruction. Partial peritoneal alimentation may be feasible when other access routes are inadequate, but lymphatic obstruction is a contraindication to the peritoneal administration of lipid emulsions.

Energy Intake↗
PubMedDate not supplied

Investigational use of tissue plasminogen activator (t-PA) for occluded central venous catheters.

Urokinase and streptokinase are commonly used thrombolytic agents for fibrin obstructed central venous catheters. Although proven to be efficacious, these two agents have the potential to induce systemic fibrin breakdown and hemorrhage. We report our initial experience with tissue plasminogen activator (t-PA) for the treatment of occluded central venous catheters which failed urokinase. Of 25 incidents of catheter occlusion in 142 right atrial catheters, six failed to clear after an initial bolus dwell of urokinase. Five of these six catheters cleared following treatment with 2 mg/2 cc of t-PA with a mean of 1.5 bolus installations. The one catheter failure was due to catheter tip position and age of clot. No coagulation abnormalities or bleeding was observed. These data suggest that t-PA may be a safe, effective thrombolytic agent in the treatment of occluded central venous catheters.

Adolescent↗
PubMedDate not supplied

Unique antithymocyte serum versus OKT3 for induction immunotherapy after heart transplantation.

To determine the efficacy of a unique polyclonal rabbit antithymocyte serum (ATS), we compared 17 consecutive nonrandomized heart transplant recipients (mean age, 38 +/- 15 years) given a 7-day prophylactic postoperative course of locally produced ATS (whole serum, no Freund's adjuvant, IV) with 19 patients (mean age, 42 +/- 17 years) given 14 days of monoclonal antibody OKT3. Cyclosporine, steroid, and azathioprine dosages were similar. At 30 days the event-free incidence of rejection was 66% +/- 11% for OKT3 (2.3 events/100 patient-days) versus 47% +/- 12% for ATS (1.2 events/100 patient-days). At 60 days and thereafter, however, there was no difference in overall number of cumulative rejection episodes. Overall infection rates were similar in both groups: the ATS group tended to have more bacterial infections, whereas the OKT3 group displayed more viral infections. Antiidiotypic antibodies developed in 29% of the ATS group and in 22% of the OKT3 group. This report demonstrates the efficacy of this polyclonal serum preparation made without Freund's adjuvant when used as an adjunct for induction-prophylactic immunotherapy in heart transplant recipients when compared with OKT3.

Actuarial Analysis↗
PubMedDate not supplied

Therapy of refractory, recurrent heart rejection with multiple courses of OKT3.

The treatment for recurrent cardiac allograft rejection refractory to conventional immunotherapy is retransplantation. When retransplantation is not possible, alternative approaches must be undertaken. This report reviews the successful management of persistently recurring rejection using five serial 14-day courses of OKT3 in a 35-year-old man after two heart transplantations.

Adult↗
PubMedDate not supplied

General anesthesia with isoflurane for diaphragmatic hernia repair during ECMO.

Isoflurane has been administered via the oxygenator of the extracorporeal membrane oxygenation (ECMO) circuit to provide anesthesia and prevent hemodynamic instability during surgical repair of congenital diaphragmatic hernia. A comparison of a series of patients treated with isoflurane demonstrates that there is less fluctuation in heart rate and blood pressure than when surgery is performed under fentanyl analgesia alone.

Anesthesia, General↗
PubMedDate not supplied

Amlodipine reduces graft coronary artery disease in rat heterotopic cardiac allografts.

The long-acting dihydropyridine calcium antagonist, amlodipine, suppresses atherogenesis in experimental animals. To determine the effect of amlodipine on allograft coronary artery disease in the transplanted heart, we used a working heterotopic rat heart transplant model. All rats were immunosuppressed with cyclosporine as a single agent and randomized to a control group (n = 9) and an amlodipine-treated group (n = 9). After 90 days, rats were killed, and the extent of graft coronary artery disease was assessed by digitizing morphometry. No significant differences were noted for mean arterial blood pressure or serum total cholesterol, high-density lipoprotein cholesterol, or triglycerides at the time of death. Amlodipine was associated with significantly less narrowing in the coronary arteries (mean percent narrowing for control group, 48.9% +/- 8.2%; mean percent narrowing for amlodipine group, 25.5% +/- 9.9%; P < 0.05). These findings suggest a role for calcium channel blockers in the prevention of graft coronary artery disease.

Amlodipine↗