The indirect McCollough effect: an examination of an associative account

It has been found that viewing, for example, a red-and-black vertical grating alternating with a green homogeneous field produces a color aftereffect--a McCollough effect--on a black-and-white vertical grating (i.e., green). Viewing such colored patterns also produces an aftereffect on a noninduced horizontal grating (i.e., pink)--the indirect McCollough effect. Humphrey, Dodwell, and Emerson (1989) argued that the indirect McCollough effect is caused by opponent properties of the visual system that organize the processing of contour and color along contrasting, probably orthogonal, dimensions. Recently, however, their interpretation of the indirect McCollough effect has been challenged by some findings of Eissenberg, Allan, Siegel, and Petrov (1995). These researchers have proposed that the indirect McCollough effect, like the McCollough effect, can be explained by associative principles. The results reported here question crucial aspects of the hypothesis of Eissenberg et al.

The significance of cagA and vacA subtypes of Helicobacter pylori in the pathogenesis of inflammation and peptic ulceration

AIMS

To assess the significance of cagA and vacA subtypes of Helicobacter pylori in relation to inflammation and density of bacterial colonisation in vivo within a dyspeptic UK population.

METHODS

Dyspeptic patients who were Helicobacter pylori positive had antral samples taken for histology and culture. Gastroduodenal pathology was noted. The grade of bacterial density and inflammation was assessed using the Sydney system. Bacterial DNA was extracted and the vacA alleles and the cagA/gene typed using PCR.

RESULTS

120 patients were studied. There was high rate of cagA positive strains in this population. Bacterial density did not correlate with the presence of peptic ulceration. There was a significant association between cagA positive strains and increased inflammation and bacterial density. The vacA s1 type independently correlated with extensive chronic inflammation but there was no association with bacterial density. The vacA m type did not correlate with extent of inflammation or bacterial density.

CONCLUSIONS

The results suggest that cagA is important in the pathogenesis of inflammation and peptic ulceration. These findings are in keeping with the hypothesis that cagA acts as a marker for a cag pathogenicity island which encodes several genes involved in inflammation. The vacA s1 allele correlates with inflammation independently of cagA, possibly through its enhanced ability to produce the vacuolating cytotoxin.

Failure to transilluminate the stomach is not an absolute contraindication to PEG insertion

Percutaneous endoscopic gastrostomy (PEG) tubes are now a well established method of enteral feeding. With the introduction of nurse endoscopists it has been possible to site PEG tubes with only one member of medical staff being present. Furthermore transillumination of the stomach is considered by many to be essential prior to gastric puncture. We present a series of 62 consecutive PEG tube sitings performed by the same nurse endoscopist/doctor team without transillumination of the stomach prior to gastric puncture. Sixty of the 62 patients (97%) had successful PEG tube insertion. There were no immediate complications. There were two failures, neither of which related to the technique. It is concluded that failure of transillumination is not an absolute contraindication to PEG tube insertion.

Coeliac disease presenting with intraperitoneal haemorrhage

A 42-year-old man, who was previously fit and well, presented in haemorrhagic shock due to a spontaneous left mesocolonic haematoma and intraperitoneal bleed. His INR was noted to be raised on admission. Later investigations showed him to have villous atrophy on biopsy of the second part of his duodenum and a positive anti-reticulin antibody. His duodenal biopsy and INR normalized on a gluten-free diet. Coeliac disease may present with a single vitamin deficiency with potentially catastrophic results.

Phase II study of carboplatin in blast crisis of chronic myeloid leukemia: Eastern Cooperative Oncology Group Study E1992

This study was a phase II evaluation of the activity of carboplatin in patients with Philadelphia chromosome positive accelerated or blastic phase of CML. Carboplatin, 250 mg/m2/day as an intravenous continuous infusion was given for 5 days, for a total dose of 1250 mg/m2 per course. If necessary, a second induction course could be given, and patients achieving complete remission were to receive an additional consolidation cycle at the same dose. Thirty-six patients were eligible and evaluable. There were five complete and three partial remissions for an overall response rate of 22% (95% CI 10.1-39.1%). The complete remission rate was 13.9% (95% CI 4.7-29.9%). The median remission duration was 3 months (range 1.4-8.94 months) and the median survival on study for all patients was 3.5 months (95% CI, 2.4-11.4 months). The median survival of responders was 12.8 months (95% CI, 3.6-17.2 months). Three eligible patients survived 2.0, 2.5 and 3.5 years following carboplatin therapy. Carboplatin has activity in blast crisis of CML, but responses are brief. Response did allow one patient to proceed to bone marrow transplantation and two other patients to continue therapy for chronic phase disease before returning to blast crisis. Activity in combination regimens should be explored.

The efficacy and safety of diclofenac 0.1% versus prednisolone acetate 1% following trabeculectomy with adjunctive mitomycin-C

BACKGROUND AND OBJECTIVE

To evaluate the efficacy and safety of diclofenac 0.1% versus prednisolone acetate 1% following trabeculectomy with adjunctive mitomycin-C.

PATIENTS AND METHODS

The authors prospectively randomized chronic open-angle glaucoma patients who underwent trabeculectomy with adjunctive mitomycin-C to receive postoperatively either diclofenac 0.1% or prednisolone acetate 1% 4 times daily, to be tapered as inflammation resolved.

RESULTS

In the diclofenac group (n = 14), the preoperative intraocular pressure of 30.4 +/- 13.1 decreased to 12.4 +/- 6.5 mm Hg at 6 months postoperatively. In the prednisolone acetate group (n = 12), the preoperative intraocular pressure decreased from 29.1 +/- 10.4 to 12.8 +/- 4.2 mm Hg at 6 months postoperatively (P = .85). The average number of medicines used 6 months postoperatively was 0.50 +/- 0.8 in the diclofenac group and 0.24 +/- 0.6 in the prednisolone acetate group (P = .36). Adverse events were similar between groups (P = .51). One patient in the diclofenac group underwent reoperation at 1 month due to uncontrolled intraocular pressure.

CONCLUSIONS

This study shows that following trabeculectomy with adjunctive mitomycin-C, a similar intraocular pressure result may be expected when either diclofenac or prednisolone acetate is prescribed postoperatively for intraocular inflammation.

Mapping and serodiagnostic application of a dominant epitope within the human herpesvirus 8 ORF 65-encoded protein

A dominant epitope within the human herpesvirus 8 (HHV8) ORF 65-encoded protein was mapped to an 8-amino-acid (aa) sequence (RKPPSGKK [aa 162 to 169]) by an amino acid replacement method. Using a 14-aa peptide (P4) encompassing this epitope as the antigen, we developed an enzyme immunoassay for HHV8 antibodies. The presence of P4 antibodies in a panel of 61 human serum specimens was highly correlated with biopsy-confirmed Kaposi's sarcoma. The homologous Epstein-Barr virus peptide derived from BFBR3-encoded protein did not interfere with the assay, suggesting that P4 is specific for HHV8.

Phase I clinical trial of perillyl alcohol administered daily

Perillyl alcohol (POH; NSC-641066), a naturally occurring monoterpene, has shown antitumor and preventive activity in preclinical studies in rodent models. Drug-related activities that have been observed include the induction of apoptosis, cell cycle arrest, the inhibition of posttranslational modification of proteins that are involved in signal transduction, and differential gene regulation. We treated 18 patients who had advanced malignancies with POH, which was given on a continuous three-times-a-day schedule at the following doses: (a) level 1 (L1), 800 mg/m2/dose; (b) level 2 (L2), 1600 mg/m2/dose; and (c) level 3 (L3), 2400 mg/m2/dose. The main toxicity, which seemed to be dose related, was gastrointestinal and included nausea and vomiting, anorexia, unpleasant taste, satiety, and eructation. Two heavily pretreated ovarian cancer patients experienced reversible > or =grade 3 granulocytopenia. Grade 1-2 fatigue was also noted. The parent drug was not detectable in the plasma. The mean peak plasma levels of the two main metabolites on days 1 and 29 were 175 and 139 microM (L1), 472 and 311 microM (L2), and 456 and 257 microM (L3) for perillic acid (PA) and 7.1 and 9.8 microM (L1), 34.2 and 34.0 microM (L2), and 26.2 and 23.4 microM (L3) for dihydroperillic acid (DHPA). Peak levels were noted 2-3 h postingestion for PA and 3-5 h postingestion for DHPA. Metabolite half-lives measured about 2 h for each. POH, PA, and DHPA were detectable in the urine of all patients at L3. About 9% of the total dose was recovered in the first 24 h. The majority was recovered as PA; less than 1% was recovered as POH. Disease stabilization for > or =6 months was seen, although no objective tumor responses were noted. Further study of POH continues with a more frequent dosing schedule.

Helicobacter pylori cagA status, vacA genotypes and ulcer disease

OBJECTIVE

Helicobacter pylori is the causative organism of peptic ulcer disease and has two putative virulence determinants: the cagA gene which encodes a protein of unknown function in 60% of strains, and the vacA gene, which is present in all strains, although active cytotoxin is produced in only about 50% of these. The relationship between genotypes of both cagA and vacA and resultant gastroduodenal pathology is unclear. The objective of this study was to correlate vacA genotype and cagA status with gastroduodenal pathology.

METHODS

One hundred and six dyspeptic patients were studied (average age 56 years, range 19-86 years, 56 men) referred for routine endoscopy. Macroscopic evidence of gastroduodenal disease was noted and antral biopsies taken for culture and genotyping of H. pylori. The polymerase chain reaction (PCR) was used to detect the cagA and vacA genes of H. pylori using specific primers.

RESULTS

Seventy eight of the 106 (73.6%) patients were cagA positive. Of those who had peptic ulcer disease 29/32 (90.6%) were cagA positive. The presence of the cagA gene was significantly associated with peptic ulcer disease (P = 0.006). The presence of the vacA s1 genotype was also significantly associated with peptic ulcer disease (P = 0.01). The presence of the cagA gene was significantly associated with the vacA s1 genotype (P < 0.001). There was no significant difference in the distribution of the s1/m1 and s1/m2 strains between ulcer and non-ulcer patients.

CONCLUSION

There is a significant association of the cagA gene and vacA s1 signal sequence with gastroduodenal ulcer disease. The relationship of the various other vacA genotypes to gastroduodenal ulcer disease is less clear.

Multidisciplinary approach to deep-seated lesions requiring radiologically-guided fine-needle aspiration

Fine-needle aspiration (FNA) is a diagnostic modality that continues to improve in accuracy as training and experience accumulate. With increasing operator expertise and improved localization techniques, greater numbers of patients are able to benefit from FNAs performed on sites that are otherwise difficult or dangerous to reach by conventional surgery. We present a retrospective review of a 2-yr experience with radiologically-guided deep-seated FNA. In 115 cases involving transthoracic and transabdominal sites, we achieved the following overall figures: 91.9% sensitivity, 100% specificity, 93.9% diagnostic accuracy, 100% positive predictive value, and 80.6% negative predictive value. Our results are compared to those in other series. When properly applied, FNA of deep-seated lesions through image guidance is equivalent to tissue diagnosis obtained by laparotomy or surgical procedures. The benefits of FNA with or without core biopsy vs. scalpel biopsy are readily apparent when one considers the morbidity, cost, turnaround time, and trauma to the patient.

Apoptosis, bcl-2 expression, and proliferative activity in human endometrial stroma and endometrial granulated lymphocytes

Human endometrial leukocytes undergo regular cyclical changes during the menstrual cycle, with a striking increase in the phenotypically unusual population of CD56+ CD16- endometrial granulated lymphocytes (eGLs) in the late secretory phase and early pregnancy. The factors that regulate this increase in eGL numbers are unclear; their unusual morphology, however, has led to the suggestion that they undergo apoptosis at the end of the menstrual cycle. Apoptosis, bcl-2 expression, and proliferative activity were examined in the stroma of normal cycling, progesterone-treated, and early-pregnancy endometrium. The expression of bcl-2 and the Ki67 proliferation marker by highly purified (> 98% CD56+) eGLs from endometrium during the menstrual cycle and from first-trimester decidua was also studied. Apoptotic cells were rarely observed in the endometrial stroma of any of the samples examined. Stromal bcl-2 expression, however, increased from the proliferative to the premenstrual phase, and double immunohistochemical labeling demonstrated large numbers of bcl-2+ CD56+ eGLs. In contrast, Ki67 expression was high in the endometrial stroma during the proliferative phase, fell during the secretory phase, and rose again premenstrually, because of expression by eGLs. Isolated CD56+ eGLs also showed high bcl-2 and Ki67 expression at the end of the menstrual cycle. Unlike premenstrual endometrium, progesterone-treated endometrium and first-trimester decidua contained few proliferating cells, expressed high levels of bcl-2, and showed no evidence of apoptosis. Thus, eGLs do not undergo apoptosis in premenstrual endometrium, and their regulatory mechanisms remain to be clarified.

Plasmablastic morphology--an independent prognostic factor with clinical and laboratory correlates: Eastern Cooperative Oncology Group (ECOG) myeloma trial E9486 report by the ECOG Myeloma Laboratory Group

We studied the prognostic significance of plasmablastic (PB) multiple myeloma (MM) in Eastern Cooperative Oncology Group Phase III trial E9486. Two reviewers independently reviewed 453 cases. They agreed on 37 PB (8.2%) cases and 416 non-PB cases, achieving an 85% concordance (P < .0001). These PB cases had significantly lower hemoglobin and serum albumin levels, higher calcium and beta 2-microglobuin levels, and higher percentage BM plasma cells (PC) by immunofluorescence. They had higher bone marrow PC labeling indices, higher serum soluble interleukin-6 receptor (sIL-6R) levels, and a higher probability of ras mutations. Three treatment regimens were used: vincristine, bis-chloro-ethyl nitrosourea (BCNU) melphalan, cyclophosphamide, and prednisone (VBMCP) alone; VBMCP with added cyclophosphamide (HiCy); or recombinant interferon alpha 2 (rIFNalpha2). Although the numbers are low, patients with PB had a significantly lower response rate versus non-PB MM when treated with VBMCP (treated, 47.1% v nontreated, 66.5% [P = .015]). Patients with nonresponding PB had a significantly higher progression rate than non-PB cases (30.6% v 11.8% [P < .0001]), especially with VBMCP alone (35.3% v 15.8% [P = .002]), and with added HiCy (37.5% v 9.8% [P < .0001]), but not with added rIFNalpha2. Event-free and overall survival of PB MM was shorter (median years, 1.1 v 2.7 and 1.9 v 3.7, respectively [P < .0001 for both]). In multivariate analysis, PB classification was also highly prognostic. There is no survival difference between the patients who were classified as PB by both reviewers versus patients classified as PB by only one reviewer. We conclude that PB MM is a discrete entity associated with more aggressive disease and shortened survival. Tumor cell ras mutations and increased sIL-6R may contribute to a higher proliferation rate and reduced survival. There were significant improvements in response and progression with the addition of HiCy and rIFNalpha2 to VBMCP, but the numbers were small and improved survival could not be shown.

The safety and efficacy of switching timolol maleate 0.5% solution to timolol hemihydrate 0.5% solution given twice daily

This study was undertaken to evaluate the safety and efficacy of switching patients treated with timolol maleate to timolol hemihydrate. In patients with ocular hypertension or chronic open-angle glaucoma treated with beta-blockers for at least three months, we prescribed timolol maleate solution 0.5% given twice daily for one month. We then switched each patient to timolol hemihydrate solution 0.5% (Betimol, Ciba Vision Ophthalmics) given twice daily for three months. This study found over the first three months in 30 completed subjects, using a worse eye analysis, that the intraocular pressure changed from 18.3+/-2.1 mm Hg on timolol maleate to 18.8+/-2.3 mm Hg on timolol hemihydrate (P=0.10) 12 hours after dosing. There was no difference in the overall incidence of unsolicited anterior segment side effects between timolol maleate (4 cases) versus timolol hemihydrate (3 cases) (P=0.69). One patient exited the study because of pain and burning in both eyes while on timolol maleate. No patient was discontinued due to loss of intraocular pressure control after switching to timolol hemihydrate. It was concluded that switching from timolol maleate to timolol hemihydrate is safe and effective in maintaining control of the intraocular pressure.

Phase I clinical and pharmacokinetic trial of penclomedine using a novel, two-stage trial design for patients with advanced malignancy

PURPOSE

A novel phase I trial design was used to determine the maximum-tolerated dose (MTD) and pharmacokinetics for penclomedine when administered as an intravenous (i.v.) infusion over 1 hour daily for 5 days, repeated every 28 days. This study also tests the feasibility of a novel two-stage design for phase I trials.

PATIENTS AND METHODS

Twenty-eight patients with advanced malignancy who met standard eligibility criteria were treated with i.v. penclomedine. The initial daily dose was 50 mg/m2. Dose escalations were planned using a modified Fibonacci sequence. One patient was enrolled on each dose level during the first stage of this trial. In the second stage, patients were enrolled in cohorts of three, proceeding in an up-and-down manner based on toxicities observed. MTD was determined by logistic regression analysis. Pharmacokinetic assessment was performed during the first cycle of treatment.

RESULTS

Dose-limiting toxicities (DLT) observed during this trial were principally neurologic and were self-limited. Although hematologic toxicity was rare, the few patients with significant hematologic changes experienced late nadirs with prolonged time to recovery. The MTD was estimated as 381 mg/m2 (80% CI, 343 to 415 mg/m2). Although there was a long elimination half-life, accumulation of penclomedine over the 5 days of administration was negligible.

CONCLUSION

The novel trial design used in this study was safe and appeared effective in limiting the numbers of patients treated at lower-dose levels. Reversible neurotoxicity was dose-limiting. Although the estimated MTD was 381 mg/m2, any dose within the CI would be reasonable for phase II study.

Endometrial leucocytes: expression of steroid hormone receptors

BACKGROUND

Stromal leucocyte populations in human endometrium comprise T cells, macrophages, and phenotypically unusual endometrial granulated lymphocytes. Their proportions vary during the menstrual cycle and, in particular, endometrial granulated lymphocytes increase in number in the late secretory phase. The stimulus responsible for these cyclical changes is unknown but it is likely that the steroid hormones oestrogen and progesterone play a role.

AIMS

To define further the expression of steroid hormone receptors by leucocytes in non-pregnant and pregnant human endometrium.

METHODS

Frozen and paraffin wax embedded sections of endometrium from non-pregnant women and early pregnancy decidua were labelled using single and double immunohistochemical techniques with monoclonal antibodies directed against oestrogen and progesterone receptors and various leucocyte subpopulations.

RESULTS

Despite the prominence of CD56 positive endometrial granulated lymphocytes in late secretory phase endometrium and early pregnancy decidua, double immunohistochemical labelling showed no evidence of expression of either progesterone or oestrogen receptors by these cells or other endometrial leucocyte populations.

CONCLUSIONS

Rather than acting directly, steroid hormones are likely to influence endometrial leucocyte populations indirectly via products of endometrial stromal or epithelial cells that express steroid hormone receptors.

A randomized phase II trial of echinomycin, trimetrexate, and cisplatin plus etoposide in patients with metastatic nonsmall cell lung carcinoma: an Eastern Cooperative Oncology Group Study (E1587)

BACKGROUND

Patients with metastatic nonsmall cell lung carcinoma (NSCLC) usually have a poor prognosis. A chemotherapy regimen containing cisplatin is commonly used for symptom palliation. Echinomycin is a potent bifunctional intercalator of double-strand DNA; trimetrexate is a new derivative of methotrexate and is active against methotrexate-resistant tumor cells in vitro.

METHODS

The Eastern Cooperative Oncology Group conducted a randomized Phase II study. Eligible patients were assigned to receive echinomycin 1200 microg/m2 by intravenous (i.v.) infusion over 30-60 minutes once a week for 4 weeks, repeated every 6 weeks; trimetrexate 12 mg/m2 i.v. bolus on Days 1-5 every 3 weeks, or 8 mg/m2 i.v. bolus on Days 1-5 for patients who had prior radiation to greater than 30% of their bone marrow; or cisplatin 60 mg/m2 i.v. on Day 1 and etoposide 120 mg/m2 i.v. on Days 1-3 every 4 weeks. Patients were evaluated before each cycle for tumor response, toxicity, and quality-of-life measurements.

RESULTS

One hundred thirty-six patients were entered on the study, and 118 were evaluable for toxicity and response. The response rates were 16%, 5%, and 5% in patients treated with cisplatin and etoposide, echinomycin, and trimetrexate, respectively. There were no complete responses. The median survival was 37.9, 24.3, and 28.0 weeks for patients who received cisplatin and etoposide, echinomycin, and trimetrexate, respectively. Although cisplatin and etoposide appeared to give better therapeutic results, the response rate or survival did not reach statistical significance. This may have been due to inadequate sample size. Neither did quality-of-life measurement show any significant differences among treatments.

CONCLUSIONS

Echinomycin and trimetrexate had minimal antitumor activity in patients with metastatic NSCLC: Response rate and survival remained poor in all three treatment arms. Patients should be encouraged to participate in clinical trials so that more effective therapy can be identified.

Assessment of right ventricular function postretrograde cardioplegia by transesophageal echocardiography

The impact of continuous retrograde cardioplegia (RCP) on right ventricular (RV) function was evaluated prospectively with intraoperative transesophageal echocardiography (TEE) in 36 patients (23 males, 13 females) with a mean age of 60.4 years (ages 24-82). Operative procedures included 12 aortic valve replacements, 16 mitral valve repair/replacements, both with or without an associated cardiac operation, and 8 Ross procedures. Mean cardiopulmonary bypass (CPB) time was 123.3 minutes (66-280 minutes) with an average cross-clamp time of 88.9 minutes (43-199 minutes). The amount of cold blood RCP ranged from 3160-18,500 mL (mean = 7382.5), and the average pulmonary artery pressure was 35/18 mmHg. The coronary sinus was distally snared in 11 patients. TEE documented biventricular global dysfunction in two patients and post-CPB with preservation of the left ventricular function in all other patients. Localized akinesis of the RV apex and outflow tract were noted in three patients, and isolated worsening tricuspid insufficiency of moderate to severe intensity in six patients. Two of the six patients with worsening tricuspid insufficiency belonged to the snared coronary sinus group (11 patients). All of the documented RV dysfunctions were new and showed no correlation with the perfusion data.

IN CONCLUSION

(1) RV apex, RV outflow tract and tricuspid valve were particularly subject to important dysfunction post-RCP; (2) RCP did not protect RV adequately in 11 patients (31%); and (3) TEE is a convenient intraoperative technique in evaluating RV dysfunction.

Intraoperative intracameral carbachol in phacoemulsification and posterior chamber lens implantation

PURPOSE

To evaluate the use of intraoperative intracameral carbachol in association with phacoemulsification and posterior lens implantation.

METHODS

We prospectively randomly assigned 41 eyes (41 patients) to receive either placebo or a 50:50 dilution of carbachol 0.01% after intraocular lens insertion and phacoemulsification.

RESULTS

Twenty-one eyes of 21 patients treated with intracameral carbachol showed a statistically significant (P = .0373) reduction in intraocular pressure (15.9 mm Hg) at 6 hours postoperatively compared with 20 eyes of 20 patients who had received placebo (20.4 mm Hg). At day 1, the carbachol group measured 15.0 mm Hg vs 17.6 mm Hg for placebo (P = .0376), and a 1.5-line improvement in visual acuity in the carbachol vs the placebo group was noted (P = .0263), which was maintained on glare testing. On quality of life testing using a modified SF-36 test, carbachol-treated patients within the first postoperative week more often attempted to descent stairs in both bright (P = .007) and dim (P = .037) light than did patients treated with placebo. At month 2, no difference was observed between groups except that depth of focus was statistically greater in the carbachol group (P = .025). Safety was similar between the two groups in terms of ocular and systemic adverse events.

CONCLUSIONS

Patients treated with carbachol intracamerally after phacoemulsification and posterior chamber lens implantation demonstrate lower intraocular pressure within the first day postoperatively. These findings are associated with improved visual acuity and potentially greater ambulation in bright light within the first postoperative week.

Shortness of breath and jaundice

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Upper limb thrombosis associated with assisted conception treatment

Three cases of upper limb deep venous thrombosis occurring in association with assisted conception treatment are presented. The accepted argument that lower limb thrombosis occurring in cases of complicated or severe hyperstimulation syndrome represents the likeliest thrombo-embolic disorder in this situation is questioned.

Thromboembolic disease associated with ovarian stimulation and assisted conception techniques

Thromboembolic disease, as a complication of ovarian stimulation and assisted conception techniques, is generally considered to be a rare complication of ovarian hyperstimulation syndrome and, by implication, lower limb in origin. Sporadic cases of unusually sited thromboses, both venous and arterial, have been reported. This paper aims to draw attention to the relatively large number of such thromboses reported in the world literature compared with those cited in previous commentaries, and to emphasize how little is known about their pathogenesis. It is believed that this is an issue which requires to be addressed in order to understand the background pathology to such incidents and if possible to identify women at greatest risk from such potentially debilitating or fatal complications, such that appropriate prophylactic measures can be taken.