Iron-Storage Disorder Presenting as Chronic Diarrhea

The involvement of the endocrine pancreas leading to bronze diabetes is well studied. However, little is known about the pathophysiology of iron dysregulation involving the exocrine pancreas. We present a unique association between the exocrine pancreas and iron dysregulation. A 45-year-old female presented with chronic diarrhea and low fecal elastase indicative of pancreatic exocrine dysfunction. MRI of the abdomen/pelvis showed iron deposition in the pancreas, suggesting an associated iron-storage disorder without features suggesting chronic pancreatitis. Association of an iron-storage disorder with pancreatic exocrine dysfunction has been reported only in one other case report. Pancreatic exocrine dysfunction can be directly associated with an iron-storage disorder that involves the pancreas. This should be included in the differential and diagnostic work-up of chronic diarrhea of unclear etiology. Based on the literature, we have highlighted the potential pathophysiology relevant to the case.

Assessment of health-related quality of life among adults hospitalized with sickle cell disease vaso-occlusive crisis

Sickle cell disease (SCD) is characterized by painful vaso-occlusive crises (VOCs). Self-reported pain intensity is often assessed with the Numeric Rating Scale (NRS), whereas newer patient-reported outcome measures (PROMs) assess multidimensional pain in SCD. We describe pain experiences among hospitalized adults with VOCs, using 2 PROMs: the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Health and the Adult Sickle Cell Quality of Life Measurement System (ASCQ-Me). Adults with SCD hospitalized with VOCs at 2 academic centers in Boston, Massachusetts, from April 2016 to October 2017 were eligible. Participants completed the NRS and PROMs at admission and 7 days postdischarge. PROM scores were described and compared with population norms. Length of stay (LOS) and 30-day readmission rates were assessed. Forty-two (96%) of 44 eligible patients consented and completed admission assessments. Mean age was 30.2 years (standard deviation, 9.1), 60% were women, 76% were non-Hispanic black, and 64% had hemoglobin SS. Twenty-seven participants (64%) completed postdischarge assessments. Sixty percent had ≥4 VOCs in the last year. Nearly all PROMIS Global Health and ASCQ-Me scores were worse than population norms. NRS and PROMIS Global Physical Health scores improved after discharge, the latter driven principally by improvements in pain. Overall median LOS was 7 days, and 30-day readmission rate was 40.5%. Administration of PROMs among adults with SCD hospitalized for VOCs is feasible and demonstrates participants experienced recurrent, prolonged, and severe VOCs. PROMIS Global and ASCQ-Me scores indicated substantial suffering, and the striking 30-day readmission rate highlights the vulnerability of these patients.

Phase 1 dose-finding study of rebastinib (DCC-2036) in patients with relapsed chronic myeloid leukemia and acute myeloid leukemia

A vailable tyrosine kinase inhibitors for chronic myeloid leukemia bind in an adenosine 5′-triphosphate-binding pocket and are affected by evolving mutations that confer resistance. Rebastinib was identified as a switch control inhibitor of BCR-ABL1 and FLT3 and may be active against resistant mutations. A Phase 1, first-in-human, single-agent study investigated rebastinib in relapsed or refractory chronic or acute myeloid leukemia. The primary objectives were to investigate the safety of rebastinib and establish the maximum tolerated dose and recommended Phase 2 dose. Fifty-seven patients received treatment with rebastinib. Sixteen patients were treated using powder-in-capsule preparations at doses from 57 mg to 1200 mg daily, and 41 received tablet preparations at doses of 100 mg to 400 mg daily. Dose-limiting toxicities were dysarthria, muscle weakness, and peripheral neuropathy. The maximum tolerated dose was 150 mg tablets administered twice daily. Rebastinib was rapidly absorbed. Bioavailability was 3- to 4-fold greater with formulated tablets compared to unformulated capsules. Eight complete hematologic responses were achieved in 40 evaluable chronic myeloid leukemia patients, 4 of which had a T315I mutation. None of the 5 patients with acute myeloid leukemia responded. Pharmacodynamic analysis showed inhibition of phosphorylation of substrates of BCR-ABL1 or FLT3 by rebastinib. Although clinical activity was observed, clinical benefit was insufficient to justify continued development in chronic or acute myeloid leukemia. Pharmacodynamic analyses suggest that other kinases inhibited by rebastinib, such as TIE2, may be more relevant targets for the clinical development of rebastinib (clinicaltrials.gov Identifier:00827138).

Cost-Effectiveness of Autologous Hematopoietic Stem Cell Transplantation for Elderly Patients with Multiple Myeloma using the Surveillance, Epidemiology, and End Results-Medicare Database

In the past decade, the number of autologous hematopoietic stem cell transplants (Auto HSCT) for older patients with multiple myeloma (MM) has increased dramatically, as has the cost of transplantation. The cost-effectiveness of this modality in patients over age 65 is unclear. Using the Surveillance, Epidemiology, and End Results-Medicare database to create a propensity-score matched sample of patients over age 65 between 2000 and 2007, we compared the survival and cost for those who received Auto HSCT to those who did not undergo transplantation but survived at least 6 months after diagnosis, and we calculated an incremental cost-effectiveness ratio (ICER). Two hundred seventy patients underwent transplantation. Median overall survival from diagnosis in those who underwent transplantation was significantly longer than in patients who did not (58 months versus 37 months, P < .001). For patients living longer than 2 years, the median monthly cost during the first year was significantly different, but the middle and last year of life costs were similar. The median cost of the first 100 days after transplantation was $60,000 (range, $37,000 to $85,000). The resultant ICER was $72,852 per life-year gained. Survival after transplantation was comparable to that in those who underwent transplantation patients under 65 years and significantly longer than older patients who did not undergo transplantation. With an ICER less than $100,000/life-year gained, Auto HSCT is cost-effective when compared with nontransplantation care in the era of novel agents and should be considered, where clinically indicated, for patients over the age of 65.

STUDIES ON VITAL STAINING : IV. INDIA INK AND BRILLIANT VITAL RED. IMPORTANCE OF CONSIDERING LIVER EXCRETION IN THE STUDY OF "BLOCKADE OF THE RETICULO-ENDOTHELIAL SYSTEM"

When brilliant vital red is injected into the blood stream of dogs much of it is slowly taken up into numerous phagocytes scattered throughout the tissues ("reticulo-endothelial system" of Aschoff). The rate at which the dye leaves the blood stream is determined in large part by the action of these phagocytic cells, but the excretion of dye into the bile is also in part responsible for the loss of dye from the plasma. The injection of a small amount of India ink into the blood stream results in lowering the rate at which the dye disappears from circulation. The fact that much of the carbon of the ink is promptly taken up by the phagocytes would lead one to suspect that they were saturated with foreign materials, or "blocked" against the entrance of dye, but it is shown that the ink causes a remarkable inhibition of the excretion of dye into the bile, and this alone seems to account for the longer retention of dye in the blood stream. There is no evidence that any of the retention is due to defective activity on the part of the phagocytes. Thus, prolonged retention of foreign materials in the blood stream cannot be cited to prove "blockade of the reticulo-endothelial system" unless one can rule out such peculiar reactions on the part of excretory organs. It is felt that the literature of "blockade" should be studied with such sources of error in mind. Preliminary studies indicate that the suppression of dye excretion by the liver is not due to the carbon content of the ink. Studies of other components of the ink are now in progress.

BLEEDING TENDENCY AND PROTHROMBIN DEFICIENCY IN BILIARY FISTULA DOGS: EFFECT OF FEEDING BILE AND VITAMIN K

In biliary fistula dogs the plasma prothrombin falls eventually to low levels and bleeding commonly occurs. Faulty absorption of vitamin K from the intestine in these animals is an important causative factor. Feeding bile permits absorption of the traces of this vitamin normally present in mixed diets, and as a result a slow rise in prothrombin level is observed. If a standard diet is supplemented with large amounts of vitamin K concentrate the prothrombin rise is rapid, provided bile or bile salt is supplied to aid in the absorption. Variations in the rate of prothrombin depletion in biliary fistula dogs kept on constant diet indicate the existence of additional factors which require further study. Our experience indicates that vitamin A and vitamin D supplements do not correct the prothrombin deficiency in biliary fistula animals.

STUDIES ON VITAL STAINING : I. SOME PROBLEMS IN COLORIMETRY. THE QUANTITATIVE ANALYSIS OF MIXTURES OF COLORED SUBSTANCES IN SOLUTION

1. A spectrophotometric method is discussed which permits quantitative analysis of colored substances present in mixtures. 2. Special attention is given to the analysis of mixtures of two dyes which are being used in a series of studies on vital staining. 3. It is shown that the method can be applied to quantitative analysis of mixtures of naturally occurring animal pigments or to mixtures of these with various other colored substances. 4. Certain limitations of the method and certain necessary precautions are discussed.

STUDIES ON VITAL STAINING : II. THE REMOVAL OF BRILLIANT VITAL RED FROM THE BLOOD STREAM. DISTRIBUTION OF DYE BETWEEN BLOOD STREAM AND BODY TISSUES

Brilliant vital red injected into the blood stream of dogs is slowly taken up by phagocytes in various parts of the body, but eventually an equilibrium is established, after which the concentration as measured in the plasma remains almost constant for long intervals of time. This equilibrium can be disturbed by injecting more dye, and in this case the phagocytes resume ingestive activity, apparently with normal or nearly normal vigor. This activity continued until a rather large part of the newly injected dye has been removed, and as the reaction again slows up we note that both plasma and tissues contain more dye than before. It is difficult to be certain that the distribution ratio of dye between plasma and tissues remains unaltered with dosage, but evidence indicates that for non toxic doses, at least, this is approximately true. This study of this partition ratio is complicated by the fact that the liver slowly excretes dye into the bile, and this helps to reduce the amount of dye in the body. Partial correction for this factor can be made by ascertaining the dye output in bile fistula dogs. These latter studies show that dye elimination into bile is relatively less efficient when large doses of dye are given to the animal than with smaller dosage. This undue retention of dye in the body with large dosage helps to maintain the dye concentration in the plasma at unduly high levels. These peculiarities in liver excretion have an important bearing on liver physiology in general, and in addition they also have an important application in connection with the theory of "blockade of the reticulo-endothelial system." It is now obvious that prolonged retention of dye in the blood stream does not of itself prove that this group of phagocytic cells is "blocked" against the entrance of foreign material. Altered excretion by liver, kidney, etc. must be ruled out before we can accept such data as evidence of "blockade."

STUDIES ON VITAL STAINING : III. THE SIMULTANEOUS INGESTION OF TWO DYESTUFFS BY PHAGOCYTES. THE QUESTION OF "BLOCKADE OF THE RETICULO-ENDOTHELIAL SYSTEM"

When large amounts of brilliant vital red are injected into the blood stream of dogs, the dye is gradually removed from circulation, and most of it is deposited in numerous phagocytic cells which are scattered throughout various organs and tissues. The dye occurs largely in the form of tiny red granules crowded together in the cytoplasm of these cells. If Niagara sky blue, a closely related dyestuff, is injected, it too is taken up and stored in these same cells. It is shown that the presence of red dye in the tissues does not inhibit the cells from taking up the blue one. The normal ability of the phagocytes to take up Niagara sky blue is observed also when this dye is injected simultaneously with brilliant vital red. This normal response toward the blue dye is seen even though the phagocytes are busied at the same time in the process of engulfing and storing the red dye. These experiments show that it is difficult if not impossible to "block" the cells with one dye so that their ability to take up another is even slightly impaired. The two dyes employed in these studies are shown to be particularly suitable for experiments of the sort here reported.

STUDIES ON VITAL STAINING : V. DOUBLE STAINING WITH BRILLIANT VITAL RED AND NIAGARA SKY BLUE. CORRELATION OF HISTOLOGICAL WITH PHYSIOLOGICAL DATA

Vital staining reactions of brilliant vital red and Niagara sky blue are studied in dogs and in rabbits. Either dye alone is taken up to form red or blue granules within the cytoplasm of macrophages and of certain other cell types. When the two dyes are injected simultaneously into the blood stream one finds that these cells build up granules which are purple from admixture of the two dyes. When several daily injections of one dye are followed by several daily injections of the other, one finds blue granules and red granules side by side within the cells, but no purple granules are found. This is thought to indicate that the dye is deposited in small foci which are active in a rather transitory way, and that the color of the granule is determined during its formative stage by the type of dye present in the fluids about the cell. The enlargement of phagocytic cells and the increase in their number with large dosage, or with repeated offerings of the dye, represents a method by which the cells maintain their phagocytic powers at the normal level. Evidence is offered to indicate that these and perhaps other compensatory changes may take place with great rapidity, so that it has been impossible to "block" or even reduce noticeably the ability of these cells to take up additional quantities of dye. Certain pitfalls in the experimental study of "blockade" are pointed out.

PROTHROMBIN DEFICIENCY AND THE BLEEDING TENDENCY IN LIVER INJURY (CHLOROFORM INTOXICATION)

The bleeding tendency in acute chloroform intoxication is due to deficiency in both plasma fibrinogen and plasma prothrombin. If the disorder is mild, no bleeding occurs. However, the prothrombin falls to rather low levels, although the fibrinogen falls only moderately. A bleeding tendency may also be produced by giving small repeated doses of chloroform. In such experiments, the hemorrhagic tendency is due to a deficiency in prothrombin alone. The fibrinogen level is unaffected. The relation of the liver injury to the plasma prothrombin level indicates that the liver is concerned in the manufacture of prothrombin. Prothrombin formation appears to be more easily interfered with than does fibrinogen formation.

Sickle cell disease due to compound heterozygosity for Hb S and a novel 7.7-kb beta-globin gene deletion

A young woman originally from Cape Verde islands presented with mild sickle cell disease. Her blood counts and hemoglobin analysis results initially suggested that she might be either homozygous for the sickle cell hemoglobin (Hb S) with concomitant alpha-thalassemia, or compound heterozygous for Hb S and beta0-thalassemia, deletional deltabeta-thalassemia or hereditary persistence of fetal hemoglobin (HPFH). We utilized a novel polymerase chain reaction (PCR)-based screening technique and found a hitherto unrecognized 7.7-kb deletion, starting from the HBB IVSII to 3' downstream of the beta-globin gene. This diagnostic approach can be applied to decipher other similar deletional mutations. This is the second known deletion that removes the 3'-end but preserves the integrity of the 5'-end of the beta-globin gene. Furthermore, the identification of the deletion allows proper genetic counseling for affected families.

Locomotor inhibition, yawning and vacuous chewing induced by a novel dopamine D2 post-synaptic receptor agonist

The N-n-propyl analog of dihydrexidine ((+/-)-trans-10, 11-dihydroxy-5,6,6a,7,8,12b-hexahydrobenzo[a]phenanthridine) is a dopamine receptor agonist with high affinity for dopamine D2 and D3 receptors (K0.5 = 26 and 5 nM, respectively). Members of the hexahydrobenzo[a]phenanthridine structural class are atypical because they display high intrinsic activity at post-synaptic dopamine D2 receptors, but low intrinsic activity at dopamine D2 autoreceptors. The present study examined the effects of (+/-)-N-n-propyl-dihydrexidine on unconditioned behaviors in rats. The most striking results observed were large, dose-dependent decreases in locomotor activity (e.g., locomotor inhibition), and increases in vacuous chewing; yawning was also increased at the highest dose of (+/-)-N-n-propyl-dihydrexidine. The locomotor inhibition and yawning induced by (+/-)-N-n-propyl-dihydrexidine were blocked by pre-treatment with (-)-remoxipride (S(-)-3-bromo-N-((1-ethyl-2-pyrrolidinyl)-methyl)-2, 6-dimethoxybenzamide), a dopamine D2 receptor antagonist, but not by the dopamine D1 receptor antagonist (+)-SCH23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1 H-3-benzazepine). Vacuous chewing was decreased by both (-)-remoxipride and (+)-SCH23390. These data support the hypothesis that a subpopulation of post-synaptic dopamine D2 receptors has a critical role in decreases in locomotor activity and induction of vacuous chewing and yawning.

Laparoscopic and thoracoscopic assistance with CSF shunts in children

Between June 1992 and June 1994, six children underwent laparoscopic or thoracoscopic assistance in the management of cerebrospinal fluid (CSF) shunts. Four children (3 to 12 years of age) required laparoscopic assistance. Two children (5 and 10 years of age) underwent thoracoscopy with insertion of syringopleural shunts for decompression of cervicothoracic hydromyelia. Most children who require CSF decompression do not need endoscopic assistance for placement of the terminal portion of the shunt. However, in selected patients who have undergone previous abdominal procedures, in patients with a persistent pseudocyst occupying an extensive portion of the abdominal cavity, and in patients requiring removal of a disconnected shunt, laparoscopy is the ideal approach. Thoracoscopy for a syringopleural shunt prevents the need for minithoracotomy.

Influence of the T cell receptor alpha-chain on T cell reactivity and tolerance to Mls-1 in T cell receptor beta-chain transgenic mice

Previous analyses of a TCR V beta 8.1 transgenic mouse revealed multiple mechanisms of tolerance to the retroviral superantigen, Mls-1. Whereas some T cells were clonally deleted in the thymus, others became anergic in the periphery, or remained unaffected by the expression of Mls-1. In addition, a strong correlation between TCR alpha-chain usage and Mls-1 reactivity of individual transgenic V beta 8.1+ T cell hybridomas was established. Based on these observations, we speculated that the different mechanisms of tolerance were a consequence of the alpha-chain-mediated differences in Mls-1 reactivity. In the current studies, we make use of a V alpha 2-specific mAb to directly examine the role of the alpha-chain on tolerance in this transgenic model. We show, first, that V alpha 2+ CD4+ T cells, as a group, are relatively less Mls-1-reactive, and are elevated twofold in the periphery of Mls-1+ compared with Mls-1-V beta 8.1 transgenic mice. This elevated expression is also seen in the V alpha 2+ CD4+ population of mature thymocytes, but not in immature thymocytes. Second, Mls-1-induced neonatal tolerance in Mls-1-negative mice caused an increase of V alpha 2+ CD4+ T cells, comparable with the frequency of expression in transgenic mice that endogenously expressed Mls-1. Third, we have demonstrated a general correlation between the age-dependent increase in Mls-1-expression and the levels of V alpha 2+ CD4+ T cells during the first 4 wk of life. Taken together, these data suggest that the over-expression of V alpha 2+ CD4+ T cells in Mls-1+ mice is a consequence of mechanisms of tolerance, predominantly mediated by preferential lack of clonal deletion in the thymus. These data support the idea that clonal deletion is a competitive process and the influence of the TCR alpha-chain on the strength of Mls-1 reactivity of individual V beta 8.1+ transgenic T cells controls their susceptibility to clonal deletion.

Influence of the T cell receptor alpha-chain on T cell reactivity and tolerance to Mls-1 in T cell receptor beta-chain transgenic mice

Previous analyses of a TCR V beta 8.1 transgenic mouse revealed multiple mechanisms of tolerance to the retroviral superantigen, Mls-1. Whereas some T cells were clonally deleted in the thymus, others became anergic in the periphery, or remained unaffected by the expression of Mls-1. In addition, a strong correlation between TCR alpha-chain usage and Mls-1 reactivity of individual transgenic V beta 8.1+ T cell hybridomas was established. Based on these observations, we speculated that the different mechanisms of tolerance were a consequence of the alpha-chain-mediated differences in Mls-1 reactivity. In the current studies, we make use of a V alpha 2-specific mAb to directly examine the role of the alpha-chain on tolerance in this transgenic model. We show, first, that V alpha 2+ CD4+ T cells, as a group, are relatively less Mls-1-reactive, and are elevated twofold in the periphery of Mls-1+ compared with Mls-1-V beta 8.1 transgenic mice. This elevated expression is also seen in the V alpha 2+ CD4+ population of mature thymocytes, but not in immature thymocytes. Second, Mls-1-induced neonatal tolerance in Mls-1-negative mice caused an increase of V alpha 2+ CD4+ T cells, comparable with the frequency of expression in transgenic mice that endogenously expressed Mls-1. Third, we have demonstrated a general correlation between the age-dependent increase in Mls-1-expression and the levels of V alpha 2+ CD4+ T cells during the first 4 wk of life. Taken together, these data suggest that the over-expression of V alpha 2+ CD4+ T cells in Mls-1+ mice is a consequence of mechanisms of tolerance, predominantly mediated by preferential lack of clonal deletion in the thymus. These data support the idea that clonal deletion is a competitive process and the influence of the TCR alpha-chain on the strength of Mls-1 reactivity of individual V beta 8.1+ transgenic T cells controls their susceptibility to clonal deletion.

Major histocompatibility complex-specific recognition of Mls-1 is mediated by multiple elements of the T cell receptor

We have recently shown that recognition of the mouse mammary tumor virus 9-associated superantigen (vSAG-9) by murine V beta 17+ T cells is strongly influenced by the major histocompatibility complex (MHC) class II haplotype of the presenting cells, resulting in a form of MHC-restricted recognition. This finding was unexpected, because T cell recognition of another well-characterized retroviral superantigen, minor lymphocyte-stimulating antigen 1 (Mls-1), had been shown to be independent of the MHC haplotype of the presenting cell. To determine whether recognition of vSAG-9 and Mls-1 is fundamentally different, we undertook an extensive analysis of MHC haplotype influences on vSAG-9 and Mls-1 recognition by panels of T cell hybridomas. Our results show that, although most hybridomas recognized Mls-1 regardless of the MHC haplotype of the presenting cells, as previously described by others, some hybridomas exhibited unique patterns of MHC fine specificity. Thus, T cell recognition of vSAG-9 and Mls-1 is not fundamentally different, but the apparent differences can be explained in terms of frequency. The MHC fine specificity of individual Mls-1-reactive hybridomas was influenced by both V beta and non-V beta T cell receptor (TCR) elements. First, the influence of the V beta element was apparent from the observation that V beta 8.2+ hybridomas were significantly more MHC specific in their recognition of Mls-1 than V beta 8.1 hybridomas. Second, a role for the TCR alpha chain was implicated from the distinct patterns of fine specificity of Mls-1 reactivity among a panel of transgenic hybridomas that expressed an identical beta chain (V beta 8.1D beta 2J beta 2.3C beta 2). Sequence analysis revealed that junctional residues of the TCR alpha chain and/or V alpha/J alpha combinations influenced the MHC haplotype fine specificity for Mls-1. Third, D beta J beta influences were implicated, in that the transgenic hybridomas expressed distinctive patterns of Mls-1 fine specificity not represented among V beta 8.1+ nontransgenic hybridomas. The findings that T cell recognition of endogenous superantigen is MHC specific, and that this specificity correlates with non-V beta elements of the TCR, support the hypothesis that there is a direct interaction between the TCR and either polymorphic residues of the MHC class II molecule or haplotype-specific dominant peptides presented by class II.

T cell receptor alpha-chain influences reactivity to Mls-1 in V beta 8.1 transgenic mice

Most, but not all, V beta 8.1+ T cells respond to M1s-1 and are clonally deleted in the thymus of M1s-1-expressing animals. To formally examine the role of the TCR alpha-chain in reactivity and tolerance to M1s-1, we have analyzed M1s-1 reactivity in a large panel of CD4+ hybridomas generated from TCR V beta 8.1 transgenic mice, that express an identical, potentially M1s-1-reactive beta-chain. The data show that the alpha-chain strongly influences the M1s-1 reactivity of the hybridomas and that the differences in reactivity had relevance for tolerance. Thus, V alpha 11+ hybridiomas were biased toward M1s-1 reactivity and V alpha 11+ T cells were correspondingly absent from the peripheral repertoire of M1s-1-expressing transgenic mice. V alpha 2+ hybridomas, on the other hand, were biased against M1s-1 reactivity, and V alpha 2+ T cells were correspondingly amplified in the M1s-1-expressing transgenic mice. Structural analysis of the alpha-chains revealed that the M1s-1 reactivity of the V alpha 11+ hybridomas segregated precisely with family member, such that V alpha 11.1+ hybridomas were M1s-1-reactive and V alpha 11.3+ hybridomas were not M1s-1-reactive. On the other hand, there was not a clear correlation between family member and M1s-1 reactivity in the V alpha 2+ hybridomas. The hybridomas also showed striking variation in their reactivity to staphylococcal enterotoxin B (SEB), and the SEB reactivity of the V alpha 11+ hybridomas correlated precisely with family member and with M1s-1 reactivity. In contrast, there was not a clear correlation with V alpha 2+ alpha-chain structure and SEB reactivity. Also, there was no correlation between M1s-1 reactivity and SEB reactivity in individual V alpha 2+ hybridomas, suggesting that the recognition of the two superantigens by the same TCR is not equivalent. Taken together, these data define a role for the TCR alpha-chain in superantigen reactivity and T cell tolerance, and provide a structural explanation for the different fates of M1s-1-reactive T cells in normal and transgenic mice.

T cell receptor alpha-chain influences reactivity to Mls-1 in V beta 8.1 transgenic mice

Most, but not all, V beta 8.1+ T cells respond to M1s-1 and are clonally deleted in the thymus of M1s-1-expressing animals. To formally examine the role of the TCR alpha-chain in reactivity and tolerance to M1s-1, we have analyzed M1s-1 reactivity in a large panel of CD4+ hybridomas generated from TCR V beta 8.1 transgenic mice, that express an identical, potentially M1s-1-reactive beta-chain. The data show that the alpha-chain strongly influences the M1s-1 reactivity of the hybridomas and that the differences in reactivity had relevance for tolerance. Thus, V alpha 11+ hybridiomas were biased toward M1s-1 reactivity and V alpha 11+ T cells were correspondingly absent from the peripheral repertoire of M1s-1-expressing transgenic mice. V alpha 2+ hybridomas, on the other hand, were biased against M1s-1 reactivity, and V alpha 2+ T cells were correspondingly amplified in the M1s-1-expressing transgenic mice. Structural analysis of the alpha-chains revealed that the M1s-1 reactivity of the V alpha 11+ hybridomas segregated precisely with family member, such that V alpha 11.1+ hybridomas were M1s-1-reactive and V alpha 11.3+ hybridomas were not M1s-1-reactive. On the other hand, there was not a clear correlation between family member and M1s-1 reactivity in the V alpha 2+ hybridomas. The hybridomas also showed striking variation in their reactivity to staphylococcal enterotoxin B (SEB), and the SEB reactivity of the V alpha 11+ hybridomas correlated precisely with family member and with M1s-1 reactivity. In contrast, there was not a clear correlation with V alpha 2+ alpha-chain structure and SEB reactivity. Also, there was no correlation between M1s-1 reactivity and SEB reactivity in individual V alpha 2+ hybridomas, suggesting that the recognition of the two superantigens by the same TCR is not equivalent. Taken together, these data define a role for the TCR alpha-chain in superantigen reactivity and T cell tolerance, and provide a structural explanation for the different fates of M1s-1-reactive T cells in normal and transgenic mice.

The surgical treatment of skull-base tumors with intracranial extension

As a discipline, skull-base surgery via the transtemporal route has matured since 1975. Previously considered unresectable, skull-base tumors with intracranial extension can now be successfully removed by means of modification of contemporary exposures with neurosurgical collaboration. Between September 1970 and February 1986, 126 skull-base tumors have been operated on by The Otology Group, P.C. Of these, 49 had intracranial extension. In this article, techniques for tumor removal and dural defect reconstruction are outlined. A single-staged procedure is advised. The advantages of and exceptions to this format are described. Techniques that will prevent postoperative cerebrospinal fluid leakage are highlighted. Results and complications of this surgical series are discussed, and team aspects of this surgery are emphasized.

Histiocytosis X involving the cervical dura

A 1-year-old boy was treated for histiocytosis X involving the cervical dura which caused spinal cord compression.

Comparison of mannitol regimens in patients with severe head injury undergoing intracranial monitoring

Eighty patients sustaining head injuries and presenting with Glasgow Coma Scale scores of 8 or less were entered into a prospective randomized study to assess the benefit of intracranial pressure (ICP) monitoring with two regimens of mannitol administration. Group I was treated with mannitol for ICP elevations greater than 25 mm Hg, while Group II received empirical mannitol therapy irrespective of ICP readings. No statistically significant differences in mortality rate or neurological outcome were demonstrated between the two groups. These results are comparable to those of several published series of head-injured patients receiving similar treatment from 1977 to 1982. However, those series must be reassessed in light of recently published studies with treatment initiated at lower levels of ICP.

Patient positioning and nasal intubation for carotid endarterectomy

Exposure of a very rostral carotid bifurcation for endarterectomy may occasionally be difficult. We are reporting a simple yet effective way to gain several centimetres of exposure of the distal cervical portion of the internal carotid artery in this circumstance.

Cerebellopontine angle lipomas

Lipomas of the intracranial vault are uncommon lesions. Rarely, lipomas of the cerebellopontine angle have been identified. The two cases of cerebellopontine angle lipomas reported herein brings the number of recorded cases to 13.

Subdural empyema and epidural abscess in children

From January 1, 1954, through December 31, 1981, 31 children were treated at The Hospital for Sick Children in Toronto, Ontario, for subdural empyema (22 cases), epidural abscess (6 cases), and infected nidi at both subdural and epidural sites (3 cases). All but four of the children with subdural empyema were from 6 months to 2 years of age or from 12 years to 16 years of age; all children with epidural abscess fitted into the older age group. The subdural empyemas developed from varied sources, but the paranasal sinuses, the ears, and the mastoids processes were predominantly affected. Five subdural empyemas developed following craniotomy or shunt procedures. The epidural abscesses developed mostly from infections in the paranasal sinuses and the middle ears. Two of the combined infections developed from the paranasal sinuses; the third followed craniotomy. The infecting bacteria varied, but were usually Streptococci and were common to both the subdural and epidural sites. The subdural empyemas presented as focal seizures in the older group, and that group of patients was more seriously ill and had greater focal deficit; the mortality rate was 13%. Epidural abscesses only rarely presented with focal deficit, and diagnosis was delayed in most instances; no deaths occurred in this group. Two cases are reported in detail to illustrate the principles and pitfalls of surgical management of these intracranial infections in the pediatric age group.

Radiofrequency neurolysis in a clinical model. Neuropathological correlation

Reports differ on which nerve fibers are affected by radiofrequency lesions made in peripheral nerves, some stating that primarily the myelinated delta and unmyelinated C fibers are destroyed, others stating that the destruction affects all sizes of nerve fibers and both myelinated and unmyelinated fibers. This study was designed to confirm one of those two findings, and to study the role that different temperatures might play in determining which fibers are affected. Radiofrequency lesions (85 degrees C for 2 minutes) were made in dogs by placing a temperature-monitored electrode into the lumber intervertebral foramina. The dogs were killed at intervals up to 6 weeks after rhizotomy, and the lesions were studied by light and electron microscopy. In all lesions, there was a total loss of unmyelinated fibers and a nearly total loss of myelinated fibers. In other dogs, 2-minute lesions were made at 45 degrees, 55 degrees, 65 degrees, and 75 degrees C, and the lesions examined 1 week later. Again, all sizes and all types of fibers were destroyed.

Oculomotor palsy with pupillary sparing, coincidental aneurysm, and chronic lymphocytic leukemic meningeal infiltration

A patient with oculomotor palsy with pupillary sparing was shown angiographically to have an aneurysm of the internal carotid artery, which proved at operation to arise distal to the origin of the ophthalmic artery. It did not impinge on the oculomotor nerve at any point. The oculomotor palsy persisted postoperatively, and complete intrinsic and extrinsic ophthalmoplegia developed. Cytological studies of cerebrospinal fluid were then made and were positive for malignant lymphocytic leukemic cells. Despite the fact that an aneurysm causing oculomotor palsy with pupillary sparing has been reported, we recommend that nonaneurysmal causes be considered first in patients presenting with that neurological sign.

Biological features of meningiomas that determine the production of cerebral edema

Although meningiomas are known to cause varying degrees of cerebral edema, the relative importance of their location, size, histological subtype, and other histological features in the production of cerebral edema has not been studied adequately. Therefore, we undertook a retrospective analysis of 43 meningiomas excised between 1975 and 1980. The results indicate that histological subtype has no relationship to the production of cerebral edema, with one exception. Meningiomas containing partly or completely a hemangiopericytic component were the only histological subtype associated consistently with cerebral edema. The location of a meningioma per se may not determine the production of cerebral edema. A relationship between size, aggressive histological features, vascular proliferative changes, and the production of cerebral edema was seen. The need for and the nature of further studies required to explain the cerebral edema that may be associated with small meningiomas are discussed.

Odontoid compression of the brain stem in a patient with rheumatoid arthritis. Case report

Cervical spine involvement by rheumatoid arthritis is common; brain-stem compression secondary to vertical subluxation of the odontoid in patients with rheumatoid arthritis is rare. Vertical subluxation results from 1) destruction of the transverse atlantal, apical, and alar ligaments of the atlas and odontoid, and 2) bone resorption in the occipital condyles, lateral masses of the atlas, and basilar processes of the skull. Neurological symptoms result from direct compression of the brain stem or from ischemia secondary to compression of vertebral arteries, anterior spinal arteries, or small perforating arteries of the brain stem and spinal cord. A case is reported in which a slowly progressive neurological deficit developed in a woman with rheumatoid arthritis following a fall from a stretcher. Neruological symptoms represented direct compression of the medulla by the dens, a mechanism confirmed at operation and autopsy. Recognition of progressive neurological deficit is often difficult in patients with rheumatoid arthritis because of their inactivity and their atrophic and immobile joints, but is essential if appropriate decompressive or stabilizing procedures are to be done. In patients with vertical subluxation of the dens, the transoral approach with removal of the odontoid is recommended. Decompression should be extensive, including the fibrous capsule around the odontoid and overlying synovial tissue as well as the odontoid itself.

Anterior sacral meningocele: two case reports and discussion of surgical approach

Virtually all patients with anterior sacral meningocele have a pelvic mass with symptoms and signs relating to pressure of the mass on adjacent structures. Constipation is a universal complaint; urinary incontinence is common. A headache often develoips when the patient stands, due to lowered spinal fluid pressure as the meningocele sac fills. A scimitar-shaped sacrum on anterioposterior plain roentgenograms of the spine is pathognomonic. The coccyx may be absent, and the lower sacral laminate may be absent or incomplete. Myelography confirms the diagnosis and should be done with large volumes of iophendylate in order to fill the sac. Only approximately 130 anterior sacral meningoceles have been reported in the literature. This article presents 2 more cases, both seen at the North Carolina Baptist Hospital. The surgical approach to both was through a sacral laminectomy; the communicating stalk was ligated and the meningocele was removed. One patient was 11 years old and had a large suprapubic pelvic mass found on routine examination. She is neurologically normal postoperatively. The other was 7 years old and had had fecal incontinence since birth. That incontinence is less severe postoperatively and the patient is neurologaically normal.

Results of urinary diversion in patients with myelomeningocele

Among 481 children with myelomeningocele seen at the North Carolina Baptist Hospital since 1949, 46 have undergone a urinary diversion procedure, as follows: ileal loop in 43; sigmoid loop in two; and transverse colon conduit in one. The indications for diversion were incontinence in 28, urinary infection or pyelonephritis in 27, and hydronephrosis, pyelocaliectasis, and reflux in 12 patients. No deaths resulted from the diversionary procedures. One patient required early surgical revision and seven patients required late surgical revision. Two patients have since died, 44 have been followed for an average of 7.9 years, 15 for more than 10 years. Overall, of 26 patients with normal prediversionary intravenous pyelograms (IVP's), 88% now have normal or nearly normal IVP's; of 14 patients with abnormal prediversionary IVP's, 79% now have normal, improved, or unaltered IVP's. Renal function has remained normal in all 44 patients, and renal calculi have developed in 10 patients. Ileal loop diversion appears to convert a high-pressure system into a low-pressure system, thereby helping to prevent further renal damage. This procedure tends to stabilize, rather than improve, urinary-tract function. For these children already so incapacitated by their basic disease, this goal is acceptable, particularly since it also provides continence and independence from parental nursing.

Obstruction of vehicle-drivers' vision by spectacle frames

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