Effects of IgM Allotype Suppression on Serum IgM Levels,B-1 and B-2 Cells,and Antibody Responses ir Allotype Heterozygous F1 Mice

IgM allotype heterozygous F1 mice were independently suppressed for Igh6a or Igh6b to evaluate the contribution of B-1 and B-2 cells to natural serum IgM levels and Ab responses. B-2 B cells expressing IgM of the suppressed allotype were evident in the spleens of suppressed mice 4 to 6 weeks after cessation of the suppression regimen, whereas B-1 B cells of the suppressed allotype were undetectable for up to 9 months. Although serum IgM of the suppressed allotype was initially depleted in mice suppressed for either allotype, by 7 months of age, there were detectable levels of IgM of the suppressed allotype in the serum; however, the levels were significantly below that found in nonsuppressed mice. When mice were immunized with either the T-independent or T-dependent form of phosphorylcholine, those suppressed for either allotype, and consequently depleted of B-1 B cells of that allotype, did not respond with phosphorylcholine-specific IgM of the suppressed allotype. In contrast, when mice were immunized with α1-3 dextran, the Igh6a allotype-suppressed mice were able to produce dextran-specific IgM of that allotype. These results show that allotype-bearing B-1 cells of both allotypes can be effectively suppressed by this suppression protocol and this produces long-lasting effects on B-1 cell levels and serum IgM of the suppressed allotype. These observations reflect the derivation of the majority of B-1 cells from fetal-neonatal precursors, which cannot be replaced by newly emerging B-2 cells of adult origin. Their ablation by antibody treatment results in permanent alterations to the adult B-cell repertoire.     

Does too much urology damage your eyesight? Study of macular function.

A study comparing the macular function of both eyes of 130 urological surgeons was carried out to investigate whether the increased light exposure to the endoscoping eye caused any deterioration of macular function. The non-endoscoping eye was used as a control. A sophisticated computer test of colour contrast sensitivity was used. The computer assesses the degree of brightness at which the subject is just able to detect a coloured grating, and for each eye this is expressed as a threshold for the red/green axis and the blue/yellow (tritan) axis. The subjects also completed a questionnaire about their working patterns and their general and ophthalmic history and had a brief examination of the fundus. The results do not suggest that urologists are suffering any significant macular damage as a result of their work with endoscopes.     

Adult respiratory distress syndrome related to antilymphocyte globulin therapy

A 21-year-old man developed the adult respiratory distress syndrome (ARDS) within five hours of receiving antilymphocyte globulin. No other identifiable cause of ARDS was present. The mechanism for development of acute lung injury is unknown, but may be related either to direct lung cytotoxicity or to complement-mediated leukocyte and platelet destruction with secondary lung injury from inflammatory mediators.     

Depressed antigen presentation function and membrane interleukin-1 activity of peritoneal macrophages after laparotomy

Although major tissue trauma produces profound depression of cell-mediated immunity, it is not known whether surgical trauma (i.e., midline laparotomy) has any adverse effect on the antigen presentation function and membrane interleukin-1 (IL-1) activity of peritoneal macrophages. To study this, C3H/HEJ (endotoxin-tolerant) mice were anesthetized. An approximately 1-inch midline abdominal incision was made, followed by abdominal closure. On days 1, 3, 5, and 7, peritoneal macrophages were harvested by means of peritoneal lavage, and antigen presentation capability was tested by incubating various numbers of peritoneal macrophages with 2 X 10(4) D10.G4.1 cells per well in the presence of conalbumin (400 micrograms/ml). The T helper cell clone (D.10.G4.1) proliferates on recognition of conalbumin in the context of Iak and also proliferates in the presence of membrane-bound IL-1 plus concanavalin A. To measure membrane IL-1 expression in peritoneal macrophages, Concanavalin A (10 micrograms/ml) was substituted for conalbumin. Cultures were incubated for 72 hours, pulsed with tritiated thymidine, and harvested. Peritoneal macrophages from laparotomized mice induced significantly less T helper cell proliferation on days 1 and 3 in the antigen presentation assay (37% and 30%, respectively; p less than 0.05) and in the membrane IL-1 assay (14% and 10%, respectively; p less than 0.05) as compared with the control. This difference was not detectable on day 5. More effective antigen presentation capability (167% of control; p less than 0.05) was seen on day 7. Thus laparotomy by itself produces marked depression of both antigen presentation function and membrane IL-1 activity of peritoneal macrophages, which may enhance susceptibility to intra-abdominal sepsis.     

Brachial plexus injury: association with subclavian and axillary vascular trauma

Proximal upper extremity (subclavian and axillary) vascular injury (SAVI) and brachial plexus injury (BPI) occur uncommonly. However, BPI may be associated with SAVI and frequently is an important determinant of long-term disability. The medical records of patients with traumatic SAVI, BPI, or both over a 5-year period were reviewed. A total of 31 patients were identified. The group was predominantly male (28 men/3 women) with a mean age of 30.5 +/- 1.8 years (range, 15-63 years). Blunt trauma accounted for 43.5% of SAVI cases and 77.8% of BPI cases. Thirteen patients (41.9%) sustained SAVI alone (group I), 10 patients (32.2%) had combined SAVI and BPI (group II), and 8 patients (25.9%) had BPI alone (group III). Subclavian and axilliary vascular injury occurred in 10 of 18 patients (55.6%) with a BPI. Brachial plexus injury occurred in 10 of 23 patients (43.5%) with a SAVI. Patients with SAVI from blunt trauma were significantly more likely to have an associated complete BPI than patients with penetrating trauma. All patients with a complete BPI (6 patients) had an associated SAVI regardless of mechanism of injury. Only one patient with a partial BPI from blunt trauma had an associated SAVI. The Injury Severity Score was significantly higher for patients in group II. An average of 2.8 and 3.3 associated injuries were observed in patients with SAVI (groups I and II) versus patients without SAVI (group III), respectively. No patient who had a complete BPI showed an improvement in neurologic status during a mean follow-up of 7.2 months. No late vascular sequelae occurred in group-III patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of zinc toxicity on thyroid function and histology in broiler chicks

Mechanisms of zinc (Zn) toxicity are incompletely understood and data regarding potential endocrine alterations in Zn toxicity are scarce. To examine mechanisms of Zn toxicity, day-old chicks were pair-fed diets containing 5280 ppm (Hz) or 73 ppm (CON) Zn. Impaired postnatal growth, independent of feed consumption, and multiple endocrinopathies were observed following short-term (1-2 weeks) exposure to the high Zn diet. Reduced levels of serum cholesterol, high-density lipoprotein cholesterol, and growth hormone were associated with HZ feeding. Depressed levels of circulating thyroid hormones and histological evidence that follicle area of thyroids from HZ birds was 63% less than CON indicated that impaired growth of HZ birds may be caused, in part, by reduced thyroidal function.     

Weyers'' ulnar ray/oligodactyly syndrome and the association of midline malformations with ulnar ray defects.

We describe a two generation family with variable ulnar and radial ray reduction and midline craniofacial abnormalities. The features suggest a diagnosis of Weyers' ulnar ray/oligodactyly syndrome originally described in two isolated cases. Syndromes of ulnar ray reduction are briefly reviewed and the relationship between limb bud and midline development discussed.