Characteristics of corneal xenograft rejection in a discordant species combination

PURPOSE: To characterize the fate of Lewis rat corneas transplanted to Hartley guinea pigs. METHODS: Full-thickness Lewis rat corneal buttons were grafted orthotopically to Hartley guinea pigs (xenografts), ACI rats (allografts), or Lewis rats (isografts). Two panels of recipients were presensitized with xenogeneic skin grafts or allogeneic skin grafts. Serum samples were collected pre- and post-transplant and analyzed by flow cytometry and indirect immunofluorescence. RESULTS: Unlike vascularized xenografts that reject within 30 min, corneal xenografts had a mean survival time of 8 days. Presensitization with guinea pig skin grafts increased recipient IgM and IgG xenoantibody levels, as measured by flow cytometry on guinea pig hematopoietic cells, and significantly accelerated corneal xenograft rejection with a mean survival time of 5 days. Presensitization with allogeneic ACI skin grafts had no effect on xenoantibody levels or xenogeneic corneal graft survival. Guinea pig corneas stained by indirect immunofluorescence with normal rat serum exhibited low (1+) but significant binding of IgG and IgM, primarily on epithelium and stroma. Serum from Lewis rats that rejected a corneal xenograft had elevated IgG and IgM xenoantibodies that reacted strongly (4+) with guinea pig cornea and heart. CONCLUSIONS: In the discordant guinea pig-to-rat species combination, donor corneas express xenoantigens; rejection of corneal xenografts stimulates IgM and IgG xenoantibody production; sensitization to xenoantigens can accelerate corneal xenograft rejection; and discordant corneal xenografts, unlike vascularized organs, are not hyperacutely rejected.     

Fabry's disease: a multidisciplinary disorder

Fabry's disease is an X-linked hereditary disorder resulting in accumulation of a glycolipid (galactosylgalactosyl glucosylceramide) due to deficiency of alpha-galactosidase A. The diagnosis can be made by histopathologic examination of skin biopsy, low activity of alpha-galactosidase in leucocytes and genetic examination. Treatment is symptomatic. We want to stress the multidisciplinary collaboration necessary to deal with this condition, in order to prevent acceleration of symptoms.     

Two measures of nurses' attitudes toward abortion as modified by experience

Random samples of nurses in two states which differed in abortion statues were sent questionnaires. Content areas included experience with 12 specific nursing activities associated with abortion, willingness to participate in the same activities, and extent of agreement with statements related to abortion. Attitudes toward abortion were inferred from the willingness-to-participate items and from the agreement section. These two measures correlated highly suggesting a common underlying dimension. However, the two samples differed significantly in extent of agreement but did not differ in willingness to participate. These results were interpreted as supporting the position that attitudes derived from items using situational contexts might bear a better relationship to behavior. The findings also suggest that abortion facilities can probably be staffed without violating personal preferences since so many expressed willingness to participate in at least some of the activities. Comparison across the two samples suggest that increased experience or even the potential for experience with abortion patients tended to increase the favorableness of attitudes toward this issue.     

Urinary amine alterations in drug-addiction pregnancy

Urinary amines were measured in 122 drug-addiction pregnancies. The profile of the patient indicates that 86 per cent were black and had a total of 2.98 pregnancies and 1.97 living children. She made 5.4 prenatal visits to our special drug-abuse prenatal clinic. The 208 antepartum 24 hour urine determinations indicated a mean excretion of epinephrine to be 28 +/- 1.6 mug which rises to 60 mug on the first day post partum. These values indicate increased adrenal gland activity and are more than six times greater than seen in normal pregnancy. The antepartum mean 24 hour urine excretion of norepinephrine is 49.7 +/- 2.6 mug which does not change on the first postpartum day. The antepartum norepinephrine values are 50 per cent higher than seen in normal pregnancy. Drug-addiction pregnancy in patients who are well controlled on methadone have markedly increased adrenal gland activity as evidence by increased levels of epinephrine. The sympathetic nervous system activity as evidenced by urinary norepinephrine is only slightly increased. Drug addiction alters the normal homeostatic mechanisms of pregnancy.     

An Epidemiologic Study of the Effects of Carbon Disulfide on the Peripheral Nerves

Although the labor inspection had disclosed considerable exposure to carbon disulfide (CS&inf2;) in a Belgian viscose rayon factory, the company medical officer had not diagnosed any case of polyneuropathy in association with CS&inf2; exposure, although this finding had been extensively reported in the literature. Personal monitoring of CS&inf2; exposure was performed in 17 jobs. Because the working conditions in the factory had not changed since 1932, a CS&inf2; cumulative exposure index (CS&inf2; index) could be calculated for each individual. Examination of the exposed subjects (n = 111) included a self-administered questionnaire, a clinical neurologic examination, and electroneuromyography. Seventy-four workers from other plants, not exposed to CS&inf2; or to any other neurotoxic agent, served as referents. The average CS&inf2; exposures of the study group ranged from 4 to 112 mg/m(3). The data were analyzed with multiple regression methods, adjusting the effect of exposure for a number of possible confounders. Significant associations were found between the cumulative CS&inf2; index and symptoms consistent with polyneuropathy in the legs and with abnormal recruitment pattern and decrease of motor conduction velocities of the peroneal nerves. Exposures to CS&inf2; at levels below the present threshold limit value (31 mg/m(3)) were associated with significant decreases of motor conduction velocity.     

Treatment of severe asymptomatic carotid stenosis

Severe (reduction of vessel diameter by more than 70%) asymptomatic carotid artery stenosis is associated with a risk of cerebrovascular accident of 2-5% in the year following diagnosis. Results of large, prospective, randomized studies suggest that prophylactic carotid endarterectomy may be beneficial in this situation. However, the elements that must be taken into consideration before deciding to operate on an individual patient are extremely complex. Age and comorbidity (especially cardiovascular conditions) must be considered, as well as perioperative risk and expected medium- and long-term benefits, as compared with optimal conservative treatment. Decision analysis may be of considerable help in such a complex situation by considering objectively and explicitly all these epidemiologic and individual variables. Specifically, the technique makes it possible to simulate threshold probabilities of perioperative complications above which the risks of prophylactic endarterectomy outweigh its benefit, expressed as 5-year survival free of cerebrovascular event. These thresholds are 4%, 3% and 2% for a patient aged 65, 75 and 85 respectively. If 2-year event-free survival is considered, the surgical risk should not exceed 1.5% for a patient aged 65 years or 1% above that age. This type of analysis makes it possible to individualize the guidelines of international panels of experts, but ultimately the decision to operate or not must also consider the psychological profile of the patient and his attitude towards risk ("risk-seeking or risk-averse").