Intratemporal vascular tumors: detection with CT and MR imaging

The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion.     

Blood donation behavior of Hispanics in the lower Rio Grande Valley

This study was designed to determine the blood donation behavior and attitudes of Hispanic residents of the Lower Rio Grande Valley for the purpose of developing promotional and educational approaches to enhance levels of donor participation. Personal interviews of 545 respondents were conducted in English and Spanish using quota sampling and standard intercept techniques at lower- and middle-income supermarkets in five cities during a payday weekend. A number of research hypotheses were established to test for demographic, behavioral, and attitudinal differences that were observed in donors and nondonors using chi-square analysis and multiple discriminant analysis. After analyzing the difference between Hispanics and non-Hispanics for blood donation rates, all non-Hispanics were eliminated from analysis, and the remaining 419 Hispanics were evaluated on the basis of their donor behavior. Donation among Hispanics was most likely to be by better- educated, English-speaking, higher-job-status individuals who had participated in a blood donation drive. Donors tend to have parent(s) who were donors, and they were also more likely to carry an organ donor card. Donors were found to vary in their behaviors as well as their attitudes and beliefs. Perceptions of a lack of safety in donating, the risk of contracting acquired immune deficiency syndrome, and the financial motivation of donors were most pronounced among Hispanics, which indicated a need for improved education on these issues.     

Continuous extradural infusion of lignocaine 0.75% vs bupivacaine 0.125% in primiparae: quality of analgesia and influence on labour

We studied 86 primiparous women with uncomplicated pregnancy and labour requesting extradural analgesia in labour. All the women were over 36 weeks of gestation with a cephalic-presenting singleton fetus. The women were allocated randomly to two groups: group A, who received an extradural infusion of lignocaine 0.75%, after an initial dose of 10 ml of lignocaine 1.5%, and group B, who received an infusion of bupivacaine 0.125% after an initial dose of 10 ml of bupivacaine 0.25%. All the women had their labour actively managed. Assessment of analgesia during labour and delivery, and the requirements for additional top-ups were noted, as were mode of delivery, requirement for oxytocic augmentation and incidence of fetal distress. Maternal and umbilical cord plasma concentrations of lignocaine were measured at delivery in 12 women receiving extradural lignocaine. There were no statistically significant differences between the two groups in terms of the mode of delivery, incidence of fetal distress, fetal heart rate abnormalities, or Apgar scores of the babies. Women in the bupivacaine group had a significantly better quality of analgesia during both the first and second stages of labour (p = 0.0005) and required fewer top-ups than those in the lignocaine group. However, the requirement for oxytocin augmentation during the first and second stages of labour was significantly less in the lignocaine group (p = 0.004). Similarly, the duration of the second stage was shorter compared with the bupivacaine group. In spite of high plasma concentrations of lignocaine, no side effects were noted in either mothers or babies.     

Human leukocyte antigen matching and fetal loss: results of a 10 year prospective study

The role that maternal and fetal human leukocyte antigen (HLA) genes play in pregnancy is unknown, but it has been suggested that fetuses whose HLA alleles do not differ from maternal alleles (i.e. histocompatible fetuses) are more likely to be aborted than fetuses with HLA alleles that differ from maternal alleles (i.e. histoincompatible fetuses). To elucidate the role of HLA compatibility in pregnancy, we tested the hypothesis that couples who match for HLA alleles or haplotypes would have reduced fertility because only these couples could produce histocompatible fetuses. We conducted a 10 year prospective study of HLA matching and pregnancy outcome in 111 Hutterite couples, providing information on 251 pregnancies. A logistic regression analysis was performed to determine the effects of HLA matching at HLA regions and loci on pregnancy outcome (fetal loss versus delivery). Significantly increased fetal loss rates were observed among couples matching for the entire 16-locus haplotype (P = 0.002). Among the individual loci, loss rates were increased among couples matching for HLA-B (P = 0.019), HLA-C (P = 0.033) and the complement component, C4 (P = 0.043). We interpret these results as evidence that matching for the entire 16-locus haplotype and/or alleles at an HLA-B-linked locus confers significant risk for fetal loss.      

ANTAGONISM OF ATRACURIUM-INDUCED NEUROMUSCULAR BLOCKADE BY NEOSTIGMINE OR EDROPHONIUM

Antagonism of atracurium-induced neuromuscular blockade by neostigmineor edrophonium has been studied using the tetanic (50 Hz) andtrain-of-four (2 Hz) or single twitch responses of the adductorpollicis muscle in 22 anaesthetized patients. A further ninepatients not given an anticholinesterase acted as a controlgroup. In two groups (six patients for each anticholinesterase)in whom antagonism was attempted at 95–98% blockade ofthe tetanic response, recovery of the tetanic response aftertwo or three doses of edrophonium 0.75 mg kg^–1 i.v. wasnot statistically different from that in the control group;recovery after two doses of neostigmine 2.5 mg i.v. was significantlyfaster (P < 0.001). Recovery of the single twitch responseafter antagonism with edrophonium, although longer than thatwith neostigmine (P < 0.01), was significantly shorter thanin the control group (P < 0.05). When edrophonium is givenat the commencement of recovery, the initial rapid antagonismof tetanic block is not sustained, whereas antagonism by neostigmineis more persistent and the recovery phase is significantly shortened.In a further two groups of patients (n = 5) given atracurium0.3 mg kg^–1 i.v. antagonism was not attempted until thepeak height of the tetanic contraction had reached approximately50% of the control value. It was found that recovery of thetetanic and train-of-four responses was significantly faster(P < 0.05–0.001) after antagonism with edrophonium0.75 mg kg^–1 i.v. than with neostigmine 2.5mg i.v. (approx.0.04 mg kg^–1). The train-of-four response recovered moreslowly than did the tetanic response after both agents (P <0.05–0.01). Department of Anaesthetics, University College Hospital, LondonWC1. ^*Clinical Investigation Department, Clinical and Applied researchDivision, The Wellcome Research Laboratories, Beckenham, Kent.     

EVALUATION OF ATRACURIUM IN ANAESTHETIZED MAN

Atracurium is a potent competitive neuromuscular blocking agentin anaesthetized man with no cardiovascular effects at dosesrequired for paralysis. Endotracheal intubation can be accomplishedafter i.v. doses of 0.6 and 0.3 mg kg^–1, within 1 and2 min respectively. Paralysis is readily antagonized by neostigmineand is enhanced by halothane. The consistent response in termsof block and recovery which emerged when the drug was givenas increments of 0.05 or 0.1 mg kg^–1 indicates the absenceof cumulative effects. The course of action of atracurium wasappreciably shorter than that of other recognized competitiveblocking agents. Doses of 0.3–0.6 mg kg^–1 i.v. providedadequate relaxation during surgical intervention for 15–45min; spontaneous recovery without the use of neostigmine wasobserved in some patients. In addition to the non-enzymic decompositionby "Hofmann Elimination", atracurium may also undergo an enzymicester hydrolysis but, unlike suxamethonium, it may not be destroyedby pseudocholinesterase.