Antimicrobial therapy in the management of odontogenic infections: the penicillin-allergic patient

This retrospective analysis was performed to investigate whether clindamycin remains the preferred antibiotic for penicillin-allergic patients with odontogenic infections. The medical records of 311 patients admitted to the study department with odontogenic infections between 2018 and 2022 and treated with either intravenous amoxicillin-clavulanic acid (Augmentin) or intravenous clindamycin were analyzed. The Augmentin-treated group included 268 patients (86.2%) and the clindamycin-treated group included 43 patients (13.8%). Severity parameters did not differ significantly between the two groups, except for a higher prevalence of abscesses in the clindamycin-treated group (58.1% vs 41.0% in the Augmentin-treated group; P = 0.035). The clindamycin-treated group required a longer duration of intravenous antibiotics (P = 0.001) and had a higher rate of treatment failure (14.0% vs 2.2%; P = 0.002) when compared to the Augmentin-treated group, with a seven-fold increased risk of treatment failure. Moreover, significantly more isolated organisms in the clindamycin-treated group were resistant to clindamycin (P = 0.015); these were all Streptococcus anginosus group. Given the higher risk of treatment failure with clindamycin, it is necessary to choose the antibiotic treatment for penicillin-allergic patients carefully. A detailed history and allergy testing followed by combination therapy is recommended, especially in severe cases.

Intraoperative blood loss and the need for preoperative blood preparations in transgender women undergoing facial feminization surgeries: implications for surgeons

The aim of this retrospective study was to assess blood loss during facial feminization surgeries and to evaluate blood transfusion requirements. Data from the medical records of all male-to-female transgender patients (transwomen) treated with gender affirming hormones and undergoing facial feminization surgeries were analysed. The total blood loss was calculated based on the haemoglobin balanced method. Twenty transwomen (average age of 25.9 years) were enrolled. Group 1 included 10 transwomen who underwent cranioplasty, genioplasty, and mandibular angles refining, group 2 included six transwomen who underwent cranioplasty and genioplasty, and group 3 included four transwomen who underwent mandibular angles refining and genioplasty. The median calculated blood loss for groups 1, 2, and 3 was 1159.7 ml, 828.5 ml, and 546.2 ml, respectively. The group differences in surgical time, intraoperative fluid amounts, and calculated blood loss volumes were significant. None of the patients required an intraoperative blood transfusion and the hormonal treatment had no effect on the amount of calculated blood loss. Hence, blood loss during facial feminization surgeries is well controlled and does not lead to life-threatening events, precluding the possibility of providing generalized recommendations for preoperative blood transfusion preparations.

Submucosal Fibrotic Bands in Oral Lichen Planus: A Clinico-Pathological Investigation of a Newly Described Phenomenon

Fibrosis is a recognized complication of chronic inflammatory conditions, which has not yet been described in oral lichen planus. To describe characteristics of submucosal fibrotic bands in oral lichen planus. Prospective study. Patients with biopsy confirmed lichen planus were included. Clinical examination recorded fibrotic bands, mouth opening, vestibular depth loss, gingival recessions adjacent to band, lichen subtypes, areas of affected mucosa, extra-oral manifestations. Patients completed the Chronic Oral Mucosal Disease Questionnaire, with additional questions regarding stiffness, restricted opening, symptom frequency, time from diagnosis of lichen, co-existing medical conditions. 73 patients were included, 14 M, 59 F, age 28-84 (mean 61) years. Buccal fibrous bands were palpated in 22 (30.1%), 13 (59%) were bilateral. Self-reported restricted opening/stiffness were significantly associated with fibrous bands (36% Vs. 11% in controls, p = 0.02). Mouth opening less than 40 mm was recorded in only 2 (9%) with bands, none in controls. Reduced vestibular depth was significantly associated with bands (11 (50%) Vs 3 (6%) in controls, p = 0.0001).Gingival recessions adjacent to bands were recorded in 3 (13.6%). No association was demonstrated between fibrous bands and erosive lesions, extra oral involvement, smoking, age, visual analogue scale, quality of life questionaire and disease duration. Histological evaluation of one case each with and without band and control showed increased mean width of connective tissue. Submucous fibrous band is first described in the present study. It is common in oral lichen planus, may lead to feeling restricted mouth opening, stiffness, loss of vestibular depth and adjacent gingival recession.

Medication-related osteonecrosis of the jaws associated with intravitreal administration of ranibizumab

Medication-related osteonecrosis of the jaws (MRONJ) is a well-known complication that, in the majority of cases, is related to antiresorptive agents. Numerous articles have described cases of MRONJ in bisphosphonate-naïve patients treated with anti-angiogenic agents administered via various routes. A single case of MRONJ after intravitreal injection of bevacizumab has been reported. We report a case of MRONJ after intravitreal injection of a different anti-angiogenic agent - ranibizumab - for the treatment of neovascular age-related macular degeneration, in a bisphosphonate-naïve patient. Although it may be a rare complication, patients treated with multiple doses of anti-angiogenic agents should be monitored for the possible early diagnosis of MRONJ.

Comparison of the histopathological characteristics of osteomyelitis, medication-related osteonecrosis of the jaw, and osteoradionecrosis

The purpose of this study was to compare the histopathological parameters of chronic/suppurative osteomyelitis, medication-related osteonecrosis of the jaw (MRONJ), and osteoradionecrosis (ORN), and to examine the hypothesis that distinct histological features can be related to a specific disease, allowing for diagnosis based on microscopic evaluation alone. One hundred and ten samples were reviewed by two examiners in a blinded fashion, and a semi-quantitative histomorphometric analysis was performed. The parameters evaluated included the presence or absence of necrotic bone, inflammation, reactive bone formation, bacteria, and osteoclasts. No statistically significant differences were found between groups for any parameter. Necrotic bone was common to all three diagnoses. Inflammation and reactive bone formation were present in all three diagnoses. The presence of bacteria was a prominent feature in all cases. Osteoclasts were scarce in MRONJ and osteomyelitis, and non-existent in ORN. The results of this study failed to identify distinctive microscopic characteristics in any of the three entities that could be used to differentiate between them. Therefore, it is impossible to reach a specific final diagnosis based on microscopic findings alone. The role of microscopic analysis is to serve as an aid to diagnosis that must be complemented by the patient's history and imaging.

[One stage combined endoscopic and per-oral buccal fat pad approach for large oro-antral-fistula closure with secondary chronic maxillary sinusitis]

There are numerous surgical approaches for oro-antral-fistula (OAF) closure. Secondary sinus disease is still considered by many experts a relative contra indication for primary closure. To describe a single-stage combined endoscopic sinus surgery and per-oral buccal fat pad (BFP) flap approach for large OAF causing chronic maxillary sinusitis. The records of all the patients with OAF and chronic manifestations of secondary rhinosinusitis that were treated between 2010 and 2013 in our tertiary care medical center were reviewed. The exclusion criteria were: OAF 5 mm, resolved sino-nasal disease, OAF secondary to malignancy, recurrent fistula, medical history that included radiotherapy to the maxillary bone and age <18 years. Each procedure was performed by a team consisting of a rhinologist and a maxillofacial surgeon. The surgical approach included an endoscopic middle antrostomy with maxillary sinus drainage, and a per-oral BFP regional flap for OAF closure. Total OAF closure, complications and need for revision surgeries. Forty-five patients that underwent OAF closure together with sinus surgery using a combined endoscopic sinus surgery (ESS) and BFP flap approach met the inclusion criteria. There were 28 males and 17 females with a mean ± SD age of 53.5 ± 14.9 years (range 22-80 years). The presenting signs and symptoms included purulent rhinorrhea (n = 22, 48.9%), foreign body in sinus (n = 10, 22.2%) nasal congestion (n = 7, 15.5%), halitosis (n = 6, 13.3%) and pain (n = 5, 12.2%). Surgical complications included local pain (n = 2, 4.4%), persistent rhinitis (n = 2, 4.4%) and synechia (n = 1, 2.2%). One patient required revision surgery due, to an unresolved OAF. The OAF of all the other 44 patients (97.8%) was closed after the first procedure and the paranasal sinuses on the treated side were completely recovered. The mean follow-up time for the group was 7.6 ± 4.3 months (7-21 months), and no untoward sequelae or recurrence were reported. Combined, one step, endoscopic Maxillary sinus drainage together with per-oral BFP flap approach is an efficacious surgical approach for safe closure of OAFs that are complicated with secondary chronic maxillary sinusitis.

Human neutrophil antibodies in a blood donor population: a lookback study

BACKGROUND AND OBJECTIVES

Human neutrophil antibodies (HNA) have been associated with severe transfusion-related acute lung injury (TRALI). We identified HNA antibodies in a blood donor population and performed an observational lookback on patients who received products from these donors to determine whether TRALI was associated with these transfusions.

MATERIALS AND METHODS

  Human neutrophil antibodies were determined in 1171 blood donors (388 non-transfused males, 390 human leucocyte antigen (HLA) antibody-negative females and 393 HLA antibody-positive females) for IgG and IgM antibodies using a flow cytometric assay. Selected positive samples had a monoclonal antibody immobilization of granulocyte antigen (MAIGA) and neutrophil genotyping performed to confirm specificity. Lookback was performed on patients receiving blood from donors with positive samples by extracting recipient data from hospital medical records. An expert panel of three pulmonary critical care physicians reviewed the summarized data and assigned a diagnosis of TRALI, possible TRALI, cannot distinguish between TRALI and TACO, TACO and other.

RESULTS

Eight donors had HNA antibodies of which five contributed to this lookback (3-HNA-specific antibodies, 2-HNA non-specific antibodies). Seventy-six blood products were transfused from these donors into individual patients. One patient developed TRALI that was associated with a donor with a non-specific HNA antibody as well as class-I and class-II HLA antibodies.

CONCLUSION

The incidence of TRALI in this lookback was low and combined with low frequency of HNA antibodies in the donor population suggests not screening donors for HNA antibodies at this time is acceptable.

Nucleic acid testing (NAT) of organ donors: is the 'best' test the right test? A consensus conference report

Nucleic acid testing (NAT) for HIV, HBV and HCV shortens the time between infection and detection by available testing. A group of experts was selected to develop recommendations for the use of NAT in the HIV/HBV/HCV screening of potential organ donors. The rapid turnaround times needed for donor testing and the risk of death while awaiting transplantation make organ donor screening different from screening blood-or tissue donors. In donors with no identified risk factors, there is insufficient evidence to recommend routine NAT, as the benefits of NAT may not outweigh the disadvantages of NAT especially when false-positive results can lead to loss of donor organs. For donors with identified behavioral risk factors, NAT should be considered to reduce the risk of transmission and increase organ utilization. Informed consent balancing the risks of donor-derived infection against the risk of remaining on the waiting list should be obtained at the time of candidate listing and again at the time of organ offer. In conclusion, there is insufficient evidence to recommend universal prospective screening of organ donors for HIV, HCV and HBV using current NAT platforms. Further study of viral screening modalities may reduce disease transmission risk without excessive donor loss.

Comparison of demographic and donation profiles and transfusion-transmissible disease markers and risk rates in previously transfused and nontransfused blood donors

BACKGROUND

Increasing concern about transfusion transmission of variant Creutzfeldt-Jakob disease has resulted in indefinite deferral of transfused donors in France and the UK. Little is known, however, about the impact of indefinite deferral of transfused donors on blood safety and availability in the US.

STUDY DESIGN AND METHODS

Data were collected on allogeneic donations at five US blood centers during 1991 through 2000. Donation characteristics, prevalence, and incidence of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were compared between transfused and nontransfused donors. Unreported deferrable risk (UDR) and reasons to donate were evaluated with data from a mail survey.

RESULTS

Transfusion history was reported by 4.2 percent of donors. Prevalence and incidence of HIV and HBV were comparable between transfused and nontransfused donors. Although HCV incidence was similar in both groups, HCV prevalence was nearly three times higher in transfused than in nontransfused first-time donors. UDR and reasons to donate were similar in the two groups, except transfused donors were less likely to donate for screening test results (odds ratio, 0.5; 95% confidence interval, 0.3-0.8).

CONCLUSION

Transfused and nontransfused donors had similar viral incidence and comparable UDR, suggesting that indefinite deferral of transfused donors would unlikely improve blood safety. Until more is known about the prevalence and transfusion transmissibility of emerging agents, indefinite deferral of previously transfused donors in the US does not appear warranted.

Hepatitis G virus biology, epidemiology, and clinical manifestations: Implications for blood safety

Hepatitis G virus (HGV), also called GBV-C, is a single positive-standard RNA virus belonging to the Flaviviridae family. In 50% to 75% of infections, HGV is cleared with plasma RNA disappearing as anti-E2 becomes detectable; in other cases, HGV infection becomes chronic. The prevalence of HGV RNA in blood donors ranges from 1% to 4%, and the rate of anti-E2, indicating resolved infection, ranges from 3% to 14%. HGV is transmitted by transfusion of blood components and has been transmitted by nonvirally inactivated factor VIII concentrate. Despite extensive study, HGV has not been identified as a causative agent of any type of liver disease or any other known clinical condition. Molecular biology data show a lack of hepatotropism; preliminary data indicate that the site of HGV replication may be in mononuclear cells in bone marrow or spleen but not in peripheral blood or lymph nodes. The combined clinical and laboratory data strongly support the contention that HGV is not a hepatotropic virus and that this virus was inappropriately named hepatitis G. Because the data do not indicate any pathologic effects of HGV, it is not appropriate to screen the blood supply for HGV RNA.

Oversight and monitoring of blood safety in the United States

The US blood safety vigilance system is composed of a network of interwoven programs, now organized under a formal structure, with the Assistant Secretary of Health and DHHS Blood Safety Committee bearing overall responsibility. It takes advantage of the breadth of expertise and close collaborative relationship of transfusion medicine and infectious disease scientists within and outside of the government. Core elements include an array of ongoing surveillance programs for monitoring established as well as new and emerging infectious agents that may pose a risk to blood safety, and the existence of historical and contemporary repositories of donor and recipient specimens that enable rapid investigation of putative new risks. This report summarizes the historical events that shaped the US blood safety oversight system, reviews the current organization and decision-making processes related to blood safety issues, and highlights key surveillance systems and research programs which monitor the US and global blood supplies for known and potential emerging risks.

Diagnoses of patients treated with ECT: a comparison of evidence-based standards with reported use

OBJECTIVE

This study assessed the extent to which patients treated with electroconvulsive therapy (ECT) had diagnoses for which ECT is an efficacious treatment according to evidence-based standards.

METHODS

ECT use among all beneficiaries of a large New England insurance company in 1994 and 1995 was examined using a retrospective cohort design. Associations between provider characteristics and ECT use for diagnoses outside the standards were determined using logistic regression analysis.

RESULTS

A total of 996 individuals among approximately 1.2 million beneficiaries were treated with ECT. They received a total of 1,532 ECT courses. For 86.5 percent of the courses, the diagnosis was within evidence-based indications; for 13.5 percent, the diagnosis was outside the indications. In more than half of the 13.5 percent of cases, conditions were depressive disorders for which no studies have been conducted or disorders that likely had associated depressive symptoms. Patients receiving ECT for diagnoses outside evidence-based indications were more likely to have been treated by psychiatrists who graduated from medical school between 1940 and 1960 and between 1961 and 1980 than by those who graduated between 1981 and 1990. These patients were also less likely to have been treated by psychiatrists who received their medical education outside the U.S.

CONCLUSIONS

Diagnoses of patients treated with ECT were mostly within evidence-based indications. The results provide reassurance to those concerned that ECT may be used indiscriminately. If confirmed by further research, the finding that psychiatrists trained in earlier eras were more likely to use ECT for diagnoses outside evidence-based indications may offer an opportunity for targeted quality improvement.

False-positive HIV-1 test results in a low-risk screening setting of voluntary blood donation. Retrovirus Epidemiology Donor Study

CONTEXT

Persons at risk of human immunodeficiency virus 1 (HIV-1) infection, have been classified incorrectly as HIV infected because of Western blot results, but the frequency of false-positive Western blot results is unknown.

OBJECTIVES

To determine the frequency of false-positive HIV-1 Western blot results in US blood donors and to make projections to other screened populations. Secondarily, to validate an algorithm for evaluating possible false-positive cases.

DESIGN

A retrospective cohort study of HIV-1 enzyme immunoassay (EIA) and Western blot results from large blood donor screening programs in which donors with suspected false-positive Western blot results underwent HIV-1 RNA polymerase chain reaction (PCR) testing and follow-up HIV-1 serology.

SETTING

Five US blood centers participating in the Retrovirus Epidemiology Donor Study.

PARTICIPANTS

More than 5 million allogeneic and autologous blood donors who successfully donated blood at 1 of the 5 participating centers from 1991 through 1995.

MAIN OUTCOME MEASURES

Rate of false positivity by Western blot and true HIV-1 infection status as determined by HIV-1 RNA PCR and by serologic follow-up of blood donors more than 5 weeks after donation.

RESULTS

Of 421 donors who were positive for HIV-1 by Western blot, 39 (9.3%) met the criteria of possible false positivity because they lacked reactivity to p31. Of these, 20 (51.3%) were proven by PCR not to be infected with HIV-1. The false-positive prevalence was 4.8% of Western blot-positive donors and 0.0004% (1 in 251000) of all donors (95% confidence interval, 1 in 173000 to 1 in 379000 donors).

CONCLUSIONS

A false diagnosis of HIV-1 infection can result from the combination of EIA and Western blot testing in blood donor and other HIV-1 screening programs. Individuals with a positive Western blot result lacking the p31 band should be counseled that, although they may be HIV infected, there is uncertainty about this conclusion. These individuals should be further evaluated by RNA PCR testing (if feasible) and HIV serologic analysis on a follow-up sample.

[Tropisetron for the prevention of nausea and vomiting during chemotherapy: multicenter clinical study]

The antiemetic effect of tropisetron was studied in 97 cancer patients (67 men, 30 women) receiving cisplatin in doses of 75 mg/m2 or higher. On 279 chemotherapy cycles studied (max 6 per patient) 5 mg of tropisetron was administered once a day i.v on day 1 and p.o. on days 2 to 6. Efficacy preventing vomiting and nausea was measured in 24 hour period as: complete control O episodes, major control 1 to 2 episodes, minor control 3 to 4 episodes and no control 5 or more episodes. Satisfactory vomiting control (complete and major) was 69%, 63%, 82%, 88%, 96% and 96% in days 1 to 6 of cycle 1. Satisfactory nausea control (complete and major) for the same days was 70%, 66%, 72%, 85%, 92% and 97%. Similar data was obtained for the subsequent cycles. Complete vomiting control was obtained in 47%, 35%, 56%, 72%, 81% and 84% and for nausea in 42%, 39%, 48%, 64%, 81% and 87%. 19 patients presented adverse effects (19.6%). Only 2 headache episodes had a definite relation with the antiemetic drug. 12 patients discontinued the medication; 6 due to drug inefficacy, 2 to illness unrelated to the drug, 1 to lack of collaboration, and 3 due to other reasons. We conclude that tropisetron allows satisfactory control of acute and delayed vomiting in a high percentage of patients treated with high doses of cisplatin. The drug does not have significant secondary effects. Tropisetron administration in only one daily dose implies an evident advantage and a treatment cost reduction.

Male-to-female transmission of human T-cell lymphotropic virus types I and II: association with viral load. The Retrovirus Epidemiology Donor Study Group

SUMMARY

Risk factors for male-to-female sexual transmission of human T-lymphotropic virus types I and II (HTLV-I/II) were investigated among HTLV-seropositive volunteer blood donors and their long-term (> or = 6 month) sex partners. Direction of transmission in concordantly seropositive pairs was assessed by analyzing risk factors for HTLV infection. Donors and their partners were also questioned regarding sexual behaviors during their relationships; HTLV antibody titers and viral load were determined for specimens from male partners. Among 31 couples in whom HTLV-infected men likely transmitted infection to their partners (11 HTLV-I and 20 HTLV-II) and 25 male-positive, female-negative couples (8 HTLV-I and 17 HTLV-II), HTLV transmitter men had been in their relationships longer (mean 225 months vs. 122 months) and had higher viral loads (geometric mean 257,549 vs. 2,945 copies/300,000 cells for HTLV-I; 5,541 vs. 118 copies/300,000 cells for HTLV-II) than non-transmitters (P = 0.018 and P = 0.001 for duration of relationship and viral load, respectively, logistic regression analysis). Transmitter men also tended to have higher antibody titers against various env and whole virus proteins than non-transmitters. The identification of high viral load and duration of relationship as risk factors provides a biologically plausible framework in which to assess risk of sexual transmission of the HTLVs.

The cost effectiveness of preoperative autologous blood donations

BACKGROUND

Since the recognition that human immunodeficiency virus is transmissible by blood transfusion there has been increasing public and professional support for autologous blood donations before elective surgery. Autologous blood donation is, however, a more expensive process than the donation of allogeneic blood by community volunteers. Furthermore, there have been recent improvements in the safety of the volunteer blood supply.

METHODS

We used a decision-analysis model to assess the cost effectiveness of donating autologous blood for four surgical procedures. Cost data were collected from the observation of transfusion practice at the University of California, Los Angeles, in 1992. Estimates of the risks of transfusion-associated diseases and the costs of treating them came from the medical literature. Cost effectiveness was expressed in dollars per quality-adjusted year of life saved. We performed sensitivity analyses of the variables in our model and examined the effect of strategies suggested to reduce costs.

RESULTS

Substituting autologous for allogeneic blood resulted in little expected health benefit (0.0002 to 0.00044 quality-adjusted year of life saved) at considerable additional cost ($68 to $4,783 per unit of blood). The additional cost of autologous blood was primarily a function of the discarding of units that were donated but not transfused and of a more labor-intensive donation process. The cost-effectiveness ratios ranged from $235,000 to over $23 million per quality-adjusted year of life saved.

CONCLUSIONS

Given the improved safety of allogeneic transfusions today, the increased protection afforded by donating autologous blood is limited and may not justify the increased cost.

The pharmacology of sevoflurane in infants and children

BACKGROUND

Sevoflurane is a new volatile anesthetic with physical properties that should make it suitable for anesthesia (MAC of sevoflurane on oxygen alone and in 60% nitrous oxide, (MAC) of sevoflurane in oxygen alone and in 60% nitrous oxide, the hemodynamic, induction and emergence responses to sevoflurane and the metabolism to inorganic fluoride were studied in 90 ASA physical status 1 or 2 neonates, infants, and children.

METHODS

MAC of sevoflurane in oxygen was determined in six groups of subjects stratified according to age: full-term neonates, infants 1-6 and > 6-12 months and children > 1-3, > 3-5 and > 5-12 yr. MAC in 60% nitrous oxide was determined in a separate group of children 1-3 yr of age. After an inhalational induction, the trachea was intubated (except for neonates in whom an awake intubation was performed). MAC for each age group was determined using the Up-and-Down technique of Dixon.

RESULTS

MAC of sevoflurane in neonates, 3.3 +/- 0.2% and in infants 1-6 months of age, 3.2 +/- 0.1%, were similar; MAC in older infants 6-12 months and children 1-12 yr was constant at approximately 2.5%; MAC of sevoflurane in 60% nitrous oxide in children 1-3 yr of age was 2.0 +/- 0.2%. Systolic arterial pressure decreased significantly at 1 MAC before skin incision compared with awake values in all subjects except children 1-3 yr with 60% nitrous oxide and children 5-12 yr in oxygen, and then returned toward awake values after skin incision. Heart rate was unchanged at approximately 1 MAC sevoflurane before incision compared with awake values in all subjects except children > 3-5 and > 5-12 yr in whom heart rate increased before incision. Induction of anesthesia, particularly with respect to airway irritability, and emergence from sevoflurane anesthesia were not remarkable. The plasma concentration of inorganic fluoride reached maximum values (8.8-16.7 microM) 30 min after discontinuation of anesthesia.

CONCLUSIONS

We conclude that sevoflurane appears to be a suitable anesthetic agent for use in neonates, infants and children undergoing < or = 1 h of anesthesia.

Duration of time from onset of human immunodeficiency virus type 1 infectiousness to development of detectable antibody. The HIV Seroconversion Study Group

BACKGROUND

For persons newly infected with the human immunodeficiency virus type 1 (HIV-1), the time from the onset of infectivity to the development of detectable HIV-1 antibody is unknown. Persons who donate blood during this period account for nearly all instances of HIV-1 transmission from HIV-1 antibody-screened blood transfusions.

STUDY DESIGN AND METHODS

To estimate the window period from infectivity to HIV-1 antibody positivity, 701 HIV-1-seropositive blood donors who made a previous seronegative donation at 40 United States blood centers were studied. The HIV-1 antibody status was determined for at least one recipient of blood from the seronegative donation preceding the seropositive donation made by 182 of the 701 donors.

RESULTS

There were 39 seropositive recipients of blood from these 182 donors. Three donors were excluded from further analysis because the seropositive recipients of their blood had other HIV-1 risk factors or had HIV-1 infection before transfusion. The final study population comprised the remaining 179 donors, of whom 36 (20%) transmitted HIV-1 infection to recipients. When the interval between the seropositive donation and the preceding seronegative donation was less than 180 days, 46 percent of the donors transmitted HIV-1. In contrast, when that interval exceeded 540 days, only 2 percent transmitted HIV-1. A mathematical model was developed to explain the relationship between the probability that the previous seronegative donation occurred during the donor's window period of infectiousness, and hence transmitted HIV-1, as a function of both the window period and the duration between the seropositive and previous seronegative donations. This model indicated that the transmission data were most consistent with an average window period of 45 days. Assuming a log-normal window period distribution, it was estimated with 95 percent certainty that at least 90 percent of persons had a window period of less than 141 days.

CONCLUSION

The window period averages 45 days, with few, if any, donors remaining infectious and seronegative for longer than 6 months.

Hyperkalaemia: a complication of warm heart surgery

A case is presented of hyperkalaemia (13.6 mEq.L-1) occurring during cardiopulmonary bypass using warm blood cardioplegia (K+ 40-60 mEq.L-1). Treatment with epinephrine, calcium chloride, sodium bicarbonate, and furosemide reduced K+ to 6.5 mEq.L-1 within 30 min and myocardial performance was enhanced with amrinone and cardiac rhythm was controlled with A-V segmental pacing. It is believed that the hyperkalaemia resulted from a combination of the surgical procedure (mitral valve replacement) and the use of warm cardioplegia. The purpose of this report is to increase the awareness of the possibility of hyperkalaemia with warm cardioplegia and to describe a successful therapeutic regimen.

Transfusion transmission of human T-lymphotropic virus types I and II: serologic and polymerase chain reaction results in recipients identified through look-back investigations

To determine the transmissibility of human T-lymphotropic virus types I and II (HTLV-I and HTLV-II) via transfusion, persons who, from 1983 to 1989, received blood components donated by persons who subsequently tested anti-HTLV-I-positive were evaluated. It was found that 16 (30%) of 54 evaluable recipients of transfused cellular components became infected with one of the HTLVs: 8 had HTLV-I and 8 had HTLV-II. Forty percent of platelet recipients and 28 percent of red cell recipients acquired infection. The rate of transmission of HTLV-I and HTLV-II was significantly correlated with storage age of red cell units prior to transfusion: 47 percent for red cells stored < or = 14 days and 0 for red cells stored > 14 days (p < 0.01). Multiple confirmatory serologic tests performed in 46 anti-HTLV-I enzyme immunoassay-negative recipients revealed that HTLV infection could not be excluded in 3 recipients of blood components from HTLV-II-infected donors. Polymerase chain reaction established HTLV-II infection in one recipient, and the other two recipients could not be classified with respect to HTLV infection status. It appears that some HTLV-II-infected transfusion recipients will not be detected by existing HTLV-I antigen-based reagents. If it is deemed necessary to initiate or continue look-back programs to detect transfusion transmission of HTLV-II infection, it is suggested that the current testing algorithm be modified in selected cases.

Increased detection of hepatitis C virus (HCV)-infected blood donors by a multiple-antigen HCV enzyme immunoassay

A new, multiple-antigen enzyme immunoassay (EIA-2) for hepatitis C virus (HCV) antibodies was evaluated in parallel with the previously available c100-3 HCV EIA (EIA-1) in 14,068 volunteer blood donors as well as in 25 cases of transfusion-associated hepatitis C for which recipient and donor samples were available. When compared to EIA-1, the EIA-2 was more sensitive in detecting HCV-infected blood donors. The EIA-2 detected an additional 1 in 1000 EIA-1-negative, surrogate marker-negative donors who were infected with HCV as demonstrated by polymerase chain reaction (PCR). The specificity of the EIA-2 was comparable to that of the EIA-1, but the two tests appear to detect different populations of false-positive donors. Recombinant immunoblot assay-indeterminate donors were detected five times more frequently by the EIA-2; PCR demonstrated that 21 percent of these donors were infected with HCV. The greater sensitivity of EIA-2 was also found in 25 transfusion recipients with non-A, non-B hepatitis; however, in 16 percent of these cases of posttransfusion HCV infection, the EIA-2 failed to detect an HCV-seropositive donor. These data indicate that EIA-2 testing will significantly reduce, but probably not eliminate, the risk of transfusion-associated HCV infection; we estimate this residual per-unit risk to be 1 in 2000 to 1 in 6000 units transfused. On a national level, it is projected that the replacement of the anti-HCV EIA-1 with the EIA-2 will initially prevent up to 40 additional cases of transfusion-associated hepatitis C per day.

Safety of blood donations following a natural disaster

To evaluate the relative safety of blood donations given in response to a major disaster, donor demographics and infectious disease test results were compared for donations made during the 10 days following the October 17, 1989, San Francisco Bay Area earthquake and those made during the preceding 6 months. These comparisons were made for donations given to the regional blood center in the area that was immediately affected by the disaster (Irwin Memorial Blood Centers) and for those given in an unaffected region (Los Angeles/Orange Counties Region, American Red Cross Blood Services). The rate of donation increased more than 200 percent during the 5 days following the earthquake in both the disaster-affected and unaffected regions. Both the disaster-affected and unaffected regions observed significant increases in the proportions of donations by first-time donors, by persons aged 20 to 39 years, and by women. The rates of confirmed positivity for infectious disease markers for post-earthquake donations did not differ significantly from rates for homologous donations given during the preceding 6 months, particularly when the rates were adjusted for the increased representation of first-time donors. Approximately 39 percent of post-earthquake first-time donors gave blood again within the following 6-month period. It is concluded that donations given after major disasters are essentially as safe as routine donations and that active efforts to recruit these donors again can be undertaken without reservation.

Immunologic correlates of spontaneous lymphocyte proliferation in human T-lymphotropic virus infection

Previously we showed that mononuclear cells from about half of human T-lymphotropic virus (HTLV)-seropositive persons exhibit spontaneous proliferation in vitro. We sought to determine if proliferation was associated with other immunologic changes characteristic of HTLV infection. The parameters assessed were (1) percentages of lymphocytes expressing CD4 and/or CD25 (interleukin-2 receptor), (2) serum levels of soluble CD25, (3) serostatus for other viruses, (4) anti-HTLV antibody levels, and (5) HTLV type determined by polymerase chain reaction or serologic reactivity with type-specific peptides. The proliferation+ HTLV (PROL+) group, proliferation HTLV (PROL-) group, and control group showed similar percentages of CD4+, CD25+, and CD4+CD25+ lymphocytes; serum levels of soluble CD25 were also similar. Antibodies to cytomegalovirus, hepatitis B core, and hepatitis C were present in similar proportions of PROL+ and PROL+ groups. However, a significant association was found between spontaneous proliferation and anti-HTLV antibody levels; sera from 67% of PROL+ persons, but only 18% of PROL- persons, required dilution to yield absorbance values within the linear range of the anti-HTLV antibody assay. In the PROL+ group, persons whose sera required the most dilution had proliferative responses significantly higher than those whose sera required no dilution. The PROL+ and PROL groups were similar with regard to the relative distribution of HTLV-I and HTLV-II infection. These findings indicate that HTLV-related spontaneous lymphocyte proliferation is related to levels of circulating anti-HTLV antibodies, and characterizes both HTLV-I and HTLV-II infection.