Clinical and genetic profile of congenital long QT syndrome in Hong Kong: a 20-year experience in paediatrics.

INTRODUCTION: Congenital long QT syndrome (LQTS) is a genetically transmitted cardiac channelopathy that can lead to sudden cardiac death. This study aimed to report the clinical and genetic characteristics of all young patients diagnosed with LQTS in the only tertiary paediatric cardiology centre in Hong Kong. METHODS: This is a retrospective review of all paediatric and young adult patients diagnosed at our centre with LQTS from January 1997 to December 2016. The diagnosis of LQTS was established with a corrected QT interval (QTc) ≥480 ms, Schwartz score of >3 points, or the presence of a pathogenic mutation. RESULTS: Fifty-nine patients (33 males) from 52 families were included, with a mean age of 8.17 years (range, 0.00-16.95 years) at presentation. Five patients had concomitant congenital heart diseases. The mean follow-up duration was 5.33 ± 4.65 years. The mean QTc in the cohort was 504 ± 47 ms. They presented with syncope and convulsion (49%), cardiac arrest (10%), bradycardia and neonatal atrioventricular block (12%). Fifteen (25%) patients were asymptomatic at diagnosis. Thirty-eight (64.4%) patients were confirmed to have a pathogenic mutation for LQTS genes. Forty-five (76.3%) patients received beta blocker therapy. Thirteen (22.0%) patients required implantable cardioverter defibrillator. There was no mortality in the study period. The 1-, 5-, and 10-year breakthrough cardiac event-free rates were 93.0%, 80.7%, and 72.6%, respectively. CONCLUSION: Identification of the disorder, administration of beta blockers, and lifestyle modification can prevent subsequent cardiac events in LQTS. Genotyping in patients with LQTS is essential in guiding medical therapy and improving prognosis.

Marital satisfaction of Chinese mothers of children with autism and intellectual disabilities in Hong Kong.

BACKGROUND: Previous research showed an association among perceived stigma, perceived caregiving burden and marital satisfaction of mothers. However, little is known about their relationship among mothers of young children with disabilities in the Chinese context. The mediating role of perceived caregiving burden between perceived stigma and marital satisfaction was seldom explored. Hence, the present study aims to investigate the relationship between perceived stigma, perceived caregiving burden and marital satisfaction of Chinese mothers of children with intellectual disabilities or autism spectrum disorders in Hong Kong. METHODS: A cross-sectional survey using convenience sampling was conducted with mothers of pre-school children with disabilities aged from 2 to 6. A total of 160 completed questionnaires were collected from five special child care centres in Hong Kong. RESULTS: The findings in the hierarchical regression analyses showed that perceived stigma and perceived caregiving burden were significant predictors of mothers' marital satisfaction. Perceived burden, including perceived social burden, emotional burden and developmental burden but excluding time-dependence and physical burden, were found to be significant mediators between perceived stigma and marital satisfaction. CONCLUSION: To address the negative consequences brought on by stigma, measures can be taken to prevent stigmatisation and minimise the harmful effects. To alleviate mothers' perceived burden, Acceptance and Commitment Therapy, mutual support groups and psycho-educational and skills training programmes can be conducted for the mothers.

Construction and evaluation of high-quality n-ZnO nanorod/p-diamond heterojunctions.

Vertically-aligned ZnO nanorods (NRs) arrays were synthesized by a low-temperature solution method on boron-doped diamond (BDD) films. The morphology, growth direction, and crystallinity of the ZnO NRs were studied by scanning electron microscopy, X-ray diffraction and cathodoluminescence. Electrical characterization of the ZnO NR/BBD heterostructures revealed characteristic p-n junction properties with an on/off ratio of about 50 at +/- 4 V and a small reverse leakage current approximately 1 microA. Moreover, the junctions showed an ideality factor around 1.0 at a low forward voltage from 0 to 0.3 V and about 2.1 for an increased voltage ranging from 1.2 to 3.0 V, being consistent with that of an ideal diode according to the Sah-Noyce-Shockley theory.

Clinical outcome of open and laparoscopic surgery in Dukes' B and C rectal cancer: experience from a regional hospital in Hong Kong.

OBJECTIVE: To compare the long-term outcome of open and laparoscopic surgery for Dukes' B and C rectal cancer in a regional hospital in Hong Kong. DESIGN: Retrospective study. SETTING: A regional hospital in Hong Kong. MAIN OUTCOME MEASURES: Survival and local recurrence rates. PATIENTS: Patients with Dukes' B and C rectal cancers underwent elective curative open or laparoscopic surgery during the period December 2000 to December 2006. RESULTS: A total of 222 patients (open surgery, n=133; laparoscopic surgery, n=89) were assessed. The overall 3- and 5-year survival rates for all patients were 72% and 58%, respectively. Local recurrence rates were similar in both groups. Laparoscopic group had better overall survival (P=0.014), however. The overall 3-year survival rates were 79% and 68% in the laparoscopic and open groups, respectively. The corresponding 5-year rates were 75% and 52%. Multivariate analysis also demonstrated that laparoscopic surgery was a significant independent factor for better survival. Chemotherapy, local recurrence, lymph node metastasis, and poorly differentiated tumour were significantly associated with survival. CONCLUSION: Laparoscopic surgery for Dukes' B and C rectal cancer was associated with more favourable survival than with open surgery.

Recombinant human arginase inhibits proliferation of human hepatocellular carcinoma by inducing cell cycle arrest.

Human hepatocellular carcinoma (HCC) has an elevated requirement for arginine in vitro, and pegylated recombinant human arginase I (rhArg-PEG), an arginine-depleting enzyme, can inhibit the growth of arginine-dependent tumors. While supplementation of the culture medium with ornithine failed to rescue Hep3B cells from growth inhibition induced by rhArg-PEG, citrulline successfully restored cell growth. The data support the roles previously proposed for ornithine transcarbamylase (OTC) in the arginine auxotrophy and rhArg-PEG sensitivity of HCC cells. Expression profiling of argininosuccinate synthetase (ASS), argininosuccinate lyase (ASL) and OTC in 40 HCC tumor biopsy specimens predicted that 16 of the patients would be rhArg-sensitive, compared with 5 who would be sensitive to arginine deiminase (ADI), another arginine-depleting enzyme with anti-tumor activity. Furthermore, rhArg-PEG-mediated deprivation of arginine from the culture medium of different HCC cell lines produced cell cycle arrests at the G(2)/M or S phase, possibly mediated by transcriptional modulation of cyclins and/or cyclin dependent kinases (CDKs). Based on these results, together with further validation of the in vivo efficacy of rhArg-PEG against HCC, we propose that the application of rhArg-PEG alone or in combination with existing chemotherapeutic drugs may represent a specific and effective therapeutic strategy against HCC.

Predictive factors for faecal incontinence after third or fourth degree obstetric tears: a clinico-physiologic study.

OBJECTIVE: This is a prospective study to review the natural history of anorectal dysfunction after primary repair for third or fourth degree obstetric tear and to identify the predictive factors for significant faecal incontinence. METHOD: From January 2003 to December 2005, 121 consecutive women (mean age 29.9 +/- 4.7) who sustained third or fourth degree obstetric tears were assessed. All had primary repair by obstetricians. They were assessed using anorectal physiology testing and endoanal ultrasound. Short-term (3-month postpartum) and medium-term (mean 18.8 +/- 7.7 months) Wexner's continence scores were obtained. RESULTS: Among the 121 women, seven were excluded because of incomplete follow-up. At short-term assessment, 25 out of 114 women were incontinent. One of them underwent another sphincter repair for significant faecal incontinence. Twenty-one and three patients respectively, had mild (Wexner's score 1-4) and moderate (Wexner's score 5-8) symptoms. At medium-term assessment, 24 patients remained incontinent; of these, 20 had mild symptoms (Wexner's score 1-4) and four had moderate incontinence (Wexner's score 5-8). The parity (P = 0.04), degree of obstetric tear (P = 0.036) and short-term Wexner's scores at 3 months postpartum (P < 0.0001) were significantly related to the change in Wexner's scores at medium-term assessment. However, the short-term Wexner's score was the only identifiable predictive factor for significant faecal incontinence. CONCLUSION: Most women suffering from third or fourth degree obstetric tear were continent or mildly incontinent. Poor Wexner's score at short-term assessment at 3 months postpartum was predictive of faecal incontinence in the medium-term.

Prospective, case-matched study of heated and humidified carbon dioxide insufflation in laparoscopic colorectal surgery.

PURPOSE: Laparoscopic colorectal surgery is often prolonged and may cause hypothermia. It is uncertain if heated and humidified carbon dioxide (CO(2)) in laparoscopic colorectal surgery is beneficial. This is a prospective case-matched study on the use of heated and humidified CO(2) in patients undergoing laparoscopic colorectal surgery. METHOD: Twenty consecutive patients undergoing laparoscopic colorectal surgery with heated (36 degrees C) and humidified (95%) CO(2) were compared with 20 consecutive patients using standard CO(2) (30.2 degrees C). All procedures were performed by a single surgeon in an institution. The changes in core temperature during surgery, visual quality of images and the short-term clinical outcome were documented. RESULTS: The core temperature fell during surgery in both groups. Although the fall of core temperature was more in the control group, it was not statistically significant (P > 0.05). The passage of flatus was more delayed in heated and humidified group (P = 0.004), but it did not affect the hospital discharge. All the other parameters, including the quality of visual images and the postoperative pain, were similar in both groups. CONCLUSIONS: Despite better temperature maintenance (nonsignificant), pneumoperitoneum using heated and humidified CO(2) gas did not appear to have any clinical benefits in laparoscopic colorectal surgery.

Improvement in colonoscopy performance with adjunctive magnetic endoscope imaging: a randomized controlled trial.

BACKGROUND AND STUDY AIM: Although magnetic endoscope imaging (MEI) has been reported to improve the performance of colonoscopy, so far only a few randomized controlled studies have been published supporting its adjunctive role. This randomized study was designed to evaluate the role of MEI on the overall performance of colonoscopy. PATIENTS AND METHODS: Patients admitted for elective colonoscopy were recruited. They were randomly allocated into two groups, either with an MEI view (study group) or without (control group). Examinations were performed by one of the two designated, trained endoscopists. The primary end point was intubation time. Other outcome measures included completion rate, pain score graded by patients, and ease of procedure as reflected by the number of attempts at straightening the scope, the number of times of hand pressure was applied abdominally, and the need to change the patient's position. Endoscopists were also asked to score the ease of procedure. Finally, in the MEI group, endoscopists were asked to comment on whether MEI helped to locate colonic lesions during endoscopy. RESULTS: In a 12-month period, 120 patients were recruited, with 60 patients in each group. The two groups were matched for age, gender distribution, and indications for colonoscopy. No complication occurred in either group. No significant difference was observed in the intubation time and colonoscopy completion rate. Other measures of ease of procedure and pain score were also similar. However, MEI was reported by endoscopists to be helpful in locating colonic lesions in 32 % of examinations with positive findings. CONCLUSION: For trained endoscopists, the device confers no benefit in terms of performance improvement. The only identified benefit is in locating lesions. Thus, while the routine use of MEI cannot be recommended, the device could be selectively offered to patients for follow-up examination after local treatment, or to patients with small colorectal tumors in whom laparoscopic surgery is planned.

Colonic amoebic abscess mimicking carcinoma of the colon.

Amoebiasis is an uncommon disease in developed countries. Its clinical presentation can be variable and non-specific, and the diagnosis can be easily overlooked. We report a case of colonic amoebic abscess mimicking advanced colonic cancer with acute intestinal obstruction and liver metastasis. The presentation, diagnosis, and treatment of amoebiasis are also reviewed.

Laparoscopic sphincter-preserving total mesorectal excision with colonic J-pouch reconstruction: five-year results.

OBJECTIVE: To prospectively evaluate the oncologic and functional outcomes of laparoscopic total mesorectal excision (TME) with colonic J-pouch reconstruction. BACKGROUND: TME is considered the established gold standard in rectal cancer surgery. However, data on laparoscopic sphincter-preserving TME are limited. METHODS: Patients with mid or low rectal cancer underwent laparoscopic TME with colonic J-pouch reconstruction by a single surgical team. Clinical and oncologic data were prospectively recorded and analyzed. RESULTS: From March 1999 to September 2004, 105 patients underwent laparoscopic TME with colonic J-pouch reconstruction. The mean operating time was 170.4 minutes and mean blood loss was 91.5 mL. The mean anastomotic distance from the anal verge was 3.9 cm. Conversion was required in 2 cases. The mean circumferential and distal margins were 17.1 mm and 3.4 cm, respectively. There was 1 case of microscopic circumferential margin involvement and 1 case of microscopic distal margin involvement. There was no 30-day mortality, and 6 patients underwent reoperation for major complications. There was no port-site metastasis. The mean follow-up time was 26.9 months (range, 1.3-65.6 months). The actuarial 5-year cancer-specific survival and local recurrence rates were 81.3% and 8.9%, respectively. Erectile dysfunction occurred in 13.6% of males, while 2 patients developed incomplete bladder denervation. Bowel function after ileostomy closure was satisfactory, with an average bowel motion of less than 3 times per day at 2 years after ileostomy closure. CONCLUSIONS: Laparoscopic TME with colonic J-pouch reconstruction is a safe procedure with reasonable operating time and does not appear to pose any threat to the oncologic and functional outcomes.

Stapled hemorrhoidopexy vs. Harmonic Scalpel hemorrhoidectomy: a randomized trial.

PURPOSE: A randomized trial was undertaken to evaluate and compare stapled hemorrhoidopexy with excisional hemorrhoidectomy in which the Harmonic Scalpel was used. METHODS: Patients with Grade III hemorrhoids who were employed during the trial period were recruited and randomized into two groups: (1) Harmonic Scalpel hemorrhoidectomy, and (2) stapled hemorrhoidopexy. All operations were performed by a single surgeon. In the stapled group, the doughnut obtained was sent for histopathologic examination to determine whether smooth muscles were included in the specimen. Operative data and complications were recorded, and patients were followed up through a structured pro forma protocol. An independent assessor was assigned to obtain postoperative pain scores and satisfaction scores at six-month follow-up. Patients were also administered a simple questionnaire at follow-up to assess continence functions. RESULTS: Over a 20-month period, 88 patients were recruited. The two groups were matched for age and gender distribution. No significant difference was identified between the two groups in terms of operation time, blood loss, day of first bowel movement after surgery, and complication rates. Despite a similar parenteral and oral analgesic requirement, the stapled group had a significantly better pain score (P = 0.002); these patients also had a significantly shorter length of stay (P = 0.02), and on average resumed work nine days earlier than the group treated with the Harmonic Scalpel (6.7 vs. 15.6, P = 0.002). Although 88 percent of doughnuts obtained in the stapled group contained some smooth muscle fibers, no association was found between smooth muscle incorporation and postoperative continence function, and as a whole the continence outcomes of the stapled group were similar to those after Harmonic Scalpel hemorrhoidectomy. Finally, at six-month follow-up, patients who underwent the stapled procedure had significantly better satisfaction scores (P = 0.001). CONCLUSION: Stapled hemorrhoidopexy is a safe and effective procedure for Grade III hemorrhoidal disease. Patients derive greater short-term benefits of reduced pain, shorter length of stay, and earlier resumption to work. Long-term follow-up is necessary to determine whether these initial results are lasting.

Minimally invasive surgery for rectal cancer.

The present scarcity of literature on laparoscopic rectal cancer surgery makes it premature to determine whether laparoscopic surgery should be the standard of care for rectal cancer. Notwithstanding that, the available evidence proves its safety and adequate oncological clearance. Moreover, current data do not suggest any detrimental effect on the postoperative and early oncological outcomes. On the contrary, there is level three evidence showing that laparoscopic technique results in less blood loss, shorter length of stay, and reduced abdominal wound disorders and pulmonary complications, albeit the overall morbidity remains similar to that of open surgery. Long-term survival outcomes remain largely unclear, however. Hence, it is high time that laparoscopic technique should be further evaluated, preferably by means of large-scale randomized trials, to define its exact role in the treatment of rectal cancer.

A double-blind, randomized trial comparing Ligasure and Harmonic Scalpel hemorrhoidectomy.

PURPOSE: The major problem after hemorrhoidectomy is postoperative pain. New techniques have been evolved to circumvent this problem. The present study was conducted to compare the outcomes of Ligasure hemorrhoidectomy and Harmonic Scalpel hemorrhoidectomy. METHODS: This study was a double-blind, randomized controlled trial. Patients with Grade 3 and 4 hemorrhoids admitted for hemorrhoidectomy were selected and randomized into two groups: 1) Ligasure hemorrhoidectomy or 2) Harmonic Scalpel hemorrhoidectomy. The primary outcomes measured were the analgesic requirement and the postoperative pain score (assessed by an independent assessor). Secondary outcome criteria included the operating time, blood loss, hospital stay, patient satisfaction score, and early and late complications. RESULTS: Forty-nine patients were randomized into two groups (LigaSure 24, Harmonic Scalpel 25). Two patients were lost to follow-up, leaving 47 patients (LigaSure 24, Harmonic Scalpel 23) available for final analysis. The age and gender distribution were comparable. The postoperative pain score (median 2.6 vs. 4.8, P < 0.001) and postoperative oral analgesic (Dologesic) requirement (median 5 vs. 13, P = 0.001) were significantly less in the LigaSure group. The operating time (median 11 vs. 18 minutes, P < 0.001) was significantly less in the LigaSure group. The hospital stay, patient satisfaction score, percentage of patients requiring pethidine injection, percentage of patients with first bowel movement on or before the first postoperative day, and complication rates were similar between the two groups. CONCLUSIONS: Ligasure hemorrhoidectomy reduces the postoperative pain and operating time compared to the Harmonic Scalpel hemorrhoidectomy. It is a safe, effective procedure for treating Grade 3 and 4 hemorrhoids.

Laparoscopy and its current role in the management of colorectal disease.

OBJECTIVE: To evaluate the current place of laparoscopy in the management of colorectal disease. METHOD: A literature search was undertaken on Medline between the period 1991 and 2002. RESULTS: From the literature there is good evidence that the laparoscopic approach is associated with at least some short-term advantages. Improved cosmesis and better patient's satisfaction are also evident. Because of this laparoscopy has been widely employed in various benign conditions. Among others, laparoscopic stoma formation, laparoscopic resection for diverticular disease and Crohn's disease, laparoscopic rectopexy, as well as laparoscopic assisted reversal of Hartmann's procedure were commonly reported. As port site recurrence and oncological safety are of less concern, there have been increasing reports on laparoscopic resection for colorectal cancer. Although long-term follow up data is still limited, results of large prospective studies as well as various randomized trials show that recurrence and survival rates of the laparoscopic approach were at least comparable to open surgery. As experience and confidence accumulates, there are also increasing reports on technically demanding, laparoscopic sphincter-saving rectal excision. Articles on functional aspects following this type of resection also start to appear, which might be one of the future directions. CONCLUSION: The applicability of laparoscopy to colorectal disease continues to expand. Laparoscopic approach should be considered for patients with benign conditions. For colorectal cancer, results from randomized trials so far have been favourable. Hence, the authors suggest the utility of laparoscopy in potentially curable cancer can also be judiciously relaxed.

Patients' acceptance of a switch from dorzolamide to brinzolamide for the treatment of glaucoma in a clinical practice setting.

BACKGROUND: The first topically active carbonic anhydrase inhibitor, dorzolamide, was developed to circumvent the adverse systemic effects of oral carbonic anhydrase inhibitors. However, its use has been associated with ocular discomfort. OBJECTIVE: The present study examined the acceptability of brinzolamide, as measured by patients' ratings and stated preferences, in patients with glaucoma previously treated with dorzolamide in the clinical practice setting. METHODS: This was a prospective, open-label, noncomparative study conducted shortly after the approval of brinzolamide. Ophthalmologists in private practice in the continental United States were asked to select patients currently using dorzolamide as their sole or combination therapy for glaucoma. Patients underwent a screening assessment in which they were asked to rate their ocular comfort with dorzolamide on a scale from 1 to 6. Brinzolamide was then substituted for dorzolamide, and patients returned for a follow-up visit approximately 1 to 3 months later. At this visit, patients were asked about ocular comfort, their preferred medication, and whether they thought ocular comfort influenced their adherence to treatment. Intraocular pressure (IOP) was measured at both visits. RESULTS: Valid visit dates (ie, both baseline and follow-up dates) were available for 447 of 501 patients from 68 of 73 sites (range, 1-40 patients per site). Because not all measurements were available for all patients at each visit, the sample size varied for each measurement. Demographic data were not available. The switch to brinzolamide resulted in a mean decrease in IOP of approximately 0.8 mm Hg (P < 0.001, paired t test). Sixty-nine percent of patients (274/397) reported an improvement of > or =1 grade in their comfort rating with brinzolamide versus dorzolamide. The mean (+/- SD) improvement in comfort rating was 1.43 +/- 1.48 grades (P < 0.001, Wilcoxon rank sum test). When patients were asked whether their adherence to treatment was affected by the occurrence of burning and stinging, 43% (173/399) answered affirmatively. Fifty-nine percent (251/424) preferred brinzolamide to dorzolamide. At the end of the study, based on patient preference, physician judgment, and other factors, 73% of responding patients (301/410) continued with brinzolamide therapy. CONCLUSIONS: In this study, the switch from dorzolamide to brinzolamide resulted in overall improvements in comfort and ocular hypotensive efficacy. However, studies using a more rigorous randomized, controlled, crossover design are needed to support these observations.

Construction of recombinant Escherichia coli strains for polyhydroxybutyrate production using soy waste as nutrient.

Construction and comparison of recombinant Escherichia coli strains harboring the polyhydroxybutyrate (PHB) operon from Ralstonia eutropha using vectors possessing different promotors, as well as the production of PHB from soy waste by the recombinant strain, are reported. The lac promotor was the most efficient on expression of the phb operon among the three promotors studied: i.e., lac promotor, T7 promotor and the normal sigma 70 promotor. The pKS/PHB was the most efficient plasmid for phb operon expression among the three plasmids used: i.e., pKS-, pAED4, and pJM9131. It was observed that isopropyl-beta-D-thiogalactopyranoside was not required for the induction of the expression of phb operon. The cell dry wt and polyhydroxyalkanoate content by E. coli XL-1 Blue (pKS/PHB) were 3.025 g/L and 27.83%, respectively.

Significance of human T-lymphotropic virus type I indeterminant serological findings among healthy individuals.

Follow-up studies on 67 blood donors with indeterminant serological findings for human T-lymphotropic virus (HTLV) type I by standard immunoassays showed no evidence of infection by polymerase chain reaction analysis for HTLV-I or HTLV-II nucleic acids or by antibody reactivity to a unique HTLV-I recombinant envelope protein, MTA-4. Among HTLV-I- or -II-infected individuals, a history of blood transfusion, past residence in established HTLV-I endemic areas or some association with intravenous drug use were common. In contrast, 85% of indeterminant cases had none of these risk factors. These observations suggest that healthy individuals with indeterminant serology for HTLV-I should not require additional studies.

Human immunodeficiency virus type 1 detected in all seropositive symptomatic and asymptomatic individuals.

Between February 1987 and October 1988, peripheral mononuclear blood cells (PBMC) from 409 adult individuals antibody positive by Western (immuno-)blot for human immunodeficiency virus type 1 (HIV-1) (56 acquired immunodeficiency syndrome [AIDS] patients, 88 patients with AIDS-related complex, and 265 asymptomatic individuals) were consecutively cultured for HIV-1 or tested for the presence of HIV-1 DNA sequences by a polymerase chain reaction assay (PCR). We isolated HIV-1 or detected HIV-1 DNA sequences from the PBMC of all 409 HIV-1 antibody-positive individuals. None of 131 healthy HIV-1 antibody-negative individuals were HIV-1 culture positive, nor were HIV-1 DNA sequences detected by PCR in the blood specimens of 43 seronegative individuals. In addition, HIV-1 PCR and HIV-1 culture were compared in testing the PBMC of 59 HIV-1 antibody-positive and 20 HIV-1 antibody-negative hemophiliacs. Both methods were found to have sensitivities and specificities of at least 97 and 100%, respectively. In contrast, the sensitivities of serum HIV-1 antigen testing in AIDS patients and asymptomatic seropositive patients were 42 and 17%, respectively. Our ability to directly demonstrate HIV-1 infection in all HIV-1 antibody-positive individuals provides definitive support that HIV-1 antibody positivity is associated with present HIV-1 infection. Moreover, the sensitivities and specificities of PCR and culture for the detection of HIV-1 appear to be equivalent, and both methods are superior to testing for HIV-1 antigen in serum for the direct detection of HIV-1.

Absence of HIV infection in blood donors with indeterminate western blot tests for antibody to HIV-1.

To determine whether apparently healthy persons who have had repeatedly reactive enzyme immunoassays and an indeterminate Western blot assay for antibody to the human immunodeficiency virus type 1 (HIV-1) are infected with HIV-1 or HIV-2, we studied 99 such volunteer blood donors in a low-risk area of the country. The subjects were interviewed about HIV risk factors. Coded blood specimens were tested again for HIV-1 antibody (by two different enzyme immunoassays, a Western blot assay and a radioimmunoprecipitation assay) and for HIV-2 antibody by enzyme immunoassay, for HIV-1 by the serum antigen test, for HIV-1 by culture, for human T-cell leukemia virus Type I or II antibody by enzyme immunoassay, and for sequences of HIV DNA by the polymerase chain reaction. Of the 99 blood donors, 98 reported no risk factors for HIV-1 infection; 1 donor had used intravenous drugs. After a median of 14 months (range, 1 to 30) from the time of the initial test, 65 subjects (66 percent) were still repeatedly reactive for HIV-1 antibody on at least one immunoassay. In 91 subjects (92 percent) the Western blot results were still indeterminate, whereas in 8 they were negative. No donor met the criteria for a positive Western blot assay for HIV-1, and none had evidence of HIV-1 or HIV-2 infection on culture or by any other test. We conclude that persons at low risk for HIV infection who have persistent indeterminate HIV-1 Western blots are rarely if ever infected with HIV-1 or HIV-2.