Microvascular Free Flap Outcomes in Maxillectomy Defects from Invasive Fungal Sinusitis

OBJECTIVES

Microvascular free tissue transfer is routinely used for reconstructing midface defects in patients with malignancy, however, studies regarding reconstructive outcomes in invasive fungal sinusitis (IFS) are lacking. We aim to describe outcomes of free flap reconstruction for IFS defects, determine the optimal time to perform reconstruction, and if anti-fungal medications or other risk factors of an immunocompromised patient population affect reconstructive outcomes.

METHODS

Retrospective review of reconstruction for IFS (2010-2022). Age, BMI, hemoglobin A1c, number of surgical debridements, and interval from the last debridement to reconstruction were compared between patients with delayed wound healing versus those without. Predictor variables for delayed wound healing and the effect of time on free flap reconstruction were analyzed.

RESULTS

Twenty-seven patients underwent free flap reconstruction for IFS. Three patients were immunocompromised from leukemia and 21 had diabetes mellitus (DM). Patients underwent an average of four surgical debridements for treatment of IFS. The interval from the last IFS debridement to flap reconstruction was 5.58 months (±5.5). Seven flaps (25.9%) had delayed wound healing. A shorter interval of less than 2 months between the last debridement for IFS and reconstructive free flap procedure was associated with delayed wound healing (Fisher Exact Test p = 0.0062). Other factors including DM, BMI, HgA1c, and bone reconstruction were not associated with delayed wound healing.

CONCLUSION

Patients with maxillectomy defects from IFS can undergo microvascular-free flap reconstruction with good outcomes while on anti-fungal medication. Early reconstruction in the first 2 months after the last IFS debridement is associated with delayed wound healing.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1642-1647, 2024.

Free Flap Outcomes for Head and Neck Surgery in Patients with COVID-19

INTRODUCTION

Coronavirus disease 2019 (COVID-19) affects the vascular system, subjecting patients to a hypercoagulable state. This is of particular concern for the success of microvascular free flap reconstruction. This study aims to report head and neck free flap complications in patients with COVID-19 during the perioperative period. We believe these patients are more likely to experience flap complications given the hypercoagulable state.

METHODS

This is a multi-institutional retrospective case series of patients infected with COVID-19 during the perioperative period for head and neck free flap reconstruction from March 2020 to January 2022.

RESULTS

Data was collected on 40 patients from 14 institutions. Twenty-one patients (52.5%) had a positive COVID-19 test within 10 days before surgery and 7 days after surgery. The remaining patients had a positive test earlier than 10 days before surgery. A positive test caused a delay in surgery for 16 patients (40.0%) with an average delay of 44.7 days (9-198 days). Two free flap complications (5.0%) occurred with no free flap deaths. Four patients (10.0%) had surgical complications and 10 patients had medical complications (25.0%). Five patients (12.5%) suffered from postoperative COVID-19 pneumonia. Three deaths were COVID-19-related and one from cancer recurrence during the study period.

CONCLUSION

Despite the heightened risk of coagulopathy in COVID-19 patients, head and neck free flap reconstructions in patients with COVID-19 are not at higher risk for free flap complications. However, these patients are at increased risk of medical complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 2023.

The endonasal approach for treatment of cerebral aneurysms: A critical review of the literature

The last two decades of neurosurgery have seen flourishing use of the endonasal approach for the treatment of skull base tumors. Safe and effective resections of neoplasms requiring intracranial arterial dissection have been performed using this technique. Recently, there have been a growing number of case reports describing the use of the endonasal approach to surgically clip cerebral aneurysms. We review the use of these approaches in intracranial aneurysm clipping and analyze its advantages, limitations, and consider future directions. Three major electronic databases were queried using relevant search terms. Pertinent case studies of unruptured and ruptured aneurysms were considered. Data from included studies were analyzed. 8 case studies describing 9 aneurysms (4 ruptured and 5 unruptured) treated by the endonasal approach met inclusion criteria. All studies note the ability to gain proximal and distal control and successful aneurysm obliteration was obtained for 8 of 9 aneurysms. 1 intraoperative rupture occurred and was controlled, and delayed complications of cerebrospinal fluid leak, vasospasm, and hydrocephalus occurred in 1, 1, and 2 patients, respectively. Described limitations of this technique include aneurysm orientation and location, the need for lower profile technology, and challenges with handling intraoperative rupture. The endonasal approach for clipping of intracranial aneurysms can be an effective approach in only very select cases as demonstrated clinically and through cadaveric exploration. Further investigation with lower profile clip technology and additional studies need to be performed. Options of alternative therapy, limitations of this approach, and team experience must first be considered.

AlloDerm with split-thickness skin graft for coverage of the forearm free flap donor site

OBJECTIVE

Major causes of donor site morbidity after free flap harvest are lack of split-thickness skin graft (STSG) take and tendon exposure. Long-term cosmesis remains poor. AlloDerm has shown cosmetically better donor site healing, albeit prolonged healing. We sought to evaluate the use of STSG with AlloDerm compared with STSG alone.

STUDY DESIGN

Case series with chart review.

SETTING

Academic tertiary care medical center.

METHODS AND SUBJECTS

Institutional review board-approved study. Microvascular database queried from 2002 to 2012. Subjects with forearm free flaps and either AlloDerm + STSG or STSG alone for donor site reconstruction were included. Morbidity outcomes were compared.

RESULTS

Eighty patients (50 male, 30 female) received AlloDerm + STSG at the donor site. Major and minor donor site complications were 15.0% and 18.8% in the AlloDerm + STSG group compared with 10.2% and 16.9% in the STSG-only group (P = .30 and P = .72), respectively. Complete STSG loss (5.0% vs 3.0%, P = .48), tendon exposure (5.0% vs 5.4%, P = 1.0), functional impairment (2.5% vs 1.8%, P = .66), infection (8.8% vs 9.6%, P = 1.0), hematoma/seroma (5.0% vs 3.6%, P = .73), and paresthesia (1.3% vs 3.6%, P = .43) were not significant. No patients required a second STSG after loss in the AlloDerm + STSG group compared with 60% (P = .17). Cosmetic results were superior in the AlloDerm + STSG group as rated by the surgeon (3.5 vs 2.6, P = .03) and patients (3.7 vs 2.9, P = .05) on a scale of 1 to 5.

CONCLUSION

Our results suggest that the use of AlloDerm with STSG can provide thicker coverage of the forearm defect, with minimal donor site morbidity and superior cosmetic results compared with STSG alone.

Androgen treatment and recovery of function following recurrent laryngeal nerve injury in the rat

PURPOSE

To investigate the effects of the androgen testosterone propionate (TP), on regeneration of the recurrent laryngeal nerve (RLN) after unilateral crush injury using assessment of vocal fold mobility (VFM) as a measure of behavioral recovery.

METHODS

48 adult male rats underwent standardized crush injury of left RLN and received treatment in the form of 2 silastic capsules containing TP or controls receiving a blank capsule (untreated). Direct laryngoscopic assessment of vocal cord mobility was performed before, immediately following and 1, 2, 3, 4, 5 or 6 weeks post injury.

RESULTS

Treatment with TP enhanced the recovery of full VFM following crush injury of the RLN compared to controls. There was statistically significant improvement in VFM seen at the 1 and 2 week time points (p < 0.05). By 4 weeks TP-treated rats displayed a 100% recovery of VFM function, compared to only 50% by the control group.

CONCLUSIONS

TP enhances RLN functional recovery following a crush injury, which further supports its potential general applicability as a therapeutic agent in peripheral nerve injury.

Rapid Word-Learning in Normal-Hearing and Hearing-Impaired Children: Effects of Age, Receptive Vocabulary, and High-Frequency Amplification

OBJECTIVE

This study examined rapid word-learning in 5- to 14-year-old children with normal and impaired hearing. The effects of age and receptive vocabulary were examined as well as those of high-frequency amplification. Novel words were low-pass filtered at 4 kHz (typical of current amplification devices) and at 9 kHz. It was hypothesized that (1) the children with normal hearing would learn more words than the children with hearing loss, (2) word-learning would increase with age and receptive vocabulary for both groups, and (3) both groups would benefit from a broader frequency bandwidth.

DESIGN

Sixty children with normal hearing and 37 children with moderate sensorineural hearing losses participated in this study. Each child viewed a 4-minute animated slideshow containing 8 nonsense words created using the 24 English consonant phonemes (3 consonants per word). Each word was repeated 3 times. Half of the 8 words were low-pass filtered at 4 kHz and half were filtered at 9 kHz. After viewing the story twice, each child was asked to identify the words from among pictures in the slide show. Before testing, a measure of current receptive vocabulary was obtained using the Peabody Picture Vocabulary Test (PPVT-III).

RESULTS

The PPVT-III scores of the hearing-impaired children were consistently poorer than those of the normal-hearing children across the age range tested. A similar pattern of results was observed for word-learning in that the performance of the hearing-impaired children was significantly poorer than that of the normal-hearing children. Further analysis of the PPVT and word-learning scores suggested that although word-learning was reduced in the hearing-impaired children, their performance was consistent with their receptive vocabularies. Additionally, no correlation was found between overall performance and the age of identification, age of amplification, or years of amplification in the children with hearing loss. Results also revealed a small increase in performance for both groups in the extended bandwidth condition but the difference was not significant at the traditional p = 0.05 level.

CONCLUSIONS

The ability to learn words rapidly appears to be poorer in children with hearing loss over a wide range of ages. These results coincide with the consistently poorer receptive vocabularies for these children. Neither the word-learning or receptive-vocabulary measures were related to the amplification histories of these children. Finally, providing an extended high-frequency bandwidth did not significantly improve rapid word-learning for either group with these stimuli.

Hearing loss in children and adults: audiometric configuration, asymmetry, and progression

OBJECTIVE

The purpose of this study was to characterize the sensorineural hearing losses of a group of children and adults along three parameters important to the hearing instrument fitting process: 1) audiometric configuration, 2) asymmetry of loss between ears, and 3) progression of loss over several years.

DESIGN

Audiograms for 248 60- and 61-yr-old adults and 227 6-yr-old children were obtained from the audiological database at Boys Town National Research Hospital. Based on right-ear air-conduction thresholds, the configurations were assigned to one of six categories: sloping, rising, flat, u-shaped, tent-shaped, and other. Left- and right-ear thresholds were compared to determine asymmetry of loss. Progression of loss was evaluated for 132 children for whom additional audiograms over an 8-yr period were available.

RESULTS

In general, the children's hearing losses were more evenly distributed across configuration categories while most of the adult's audiograms were sloping or u-shaped in configuration. The variability of loss at each frequency was greater for the children than the adults for all configuration categories. Asymmetrical losses were more common and the degree of asymmetry at each frequency was more extensive among the children than the adults. A small number of children showed either improved or deteriorated hearing levels over time. In those children for whom progressive hearing loss occurred, no frequency was more vulnerable than another.

CONCLUSIONS

The results of the present study suggest that substantial differences in audiological characteristics exist between children and adults. Implications for amplification include the development of appropriate fitting protocols for unusual audiometric configurations as well as protocols for binaural amplification in cases of asymmetric hearing losses.

Childhood maltreatment, posttraumatic stress symptomatology, and adolescent dating violence: considering the value of adolescent perceptions of abuse and a trauma mediational model

The present study, utilizing both a child protective services and high school sample of midadolescents, examined the issue of self-report of maltreatment as it relates to issues of external validity (i.e., concordance with social worker ratings). reliability (i.e.. overlap with an alternate child maltreatment self-report inventory; association of a self-labeling item as "abused" with their subscale item counterparts), and construct validity (i.e., the association of maltreatment with posttraumatic stress symptomatology and dating violence). Relevant theoretical work in attachment, trauma, and relationship violence points to a mediational model, whereby the relationship between childhood maltreatment and adolescent dating violence would be expected to be accounted for by posttraumatic stress symptomatology. In the high school sample, 1329 adolescents and, in the CPS sample, 224 youth on the active caseloads completed comparable questionnaires in the three domains of interest. For females only, results supported a mediational model in the prediction of dating violence in both samples. For males, child maltreatment and trauma symptomatology added unique contributions to predicting dating violence. with no consistent pattern emerging across samples. When considering the issue of self-labeling as abused. CPS females who self-labeled had higher posttraumatic stress symptomatology and dating violence victimization scores than did their nonlabeling, maltreated counterparts for emotional maltreatment. These results point to the need for ongoing work in understanding the process of disclosure and how maltreatment experiences are consciously conceptualized.

Effect of stimulus bandwidth on the perception of /s/ in normal- and hearing-impaired children and adults

Recent studies with adults have suggested that amplification at 4 kHz and above fails to improve speech recognition and may even degrade performance when high-frequency thresholds exceed 50-60 dB HL. This study examined the extent to which high frequencies can provide useful information for fricative perception for normal-hearing and hearing-impaired children and adults. Eighty subjects (20 per group) participated. Nonsense syllables containing the phonemes /s/, /f/, and /O/, produced by a male, female, and child talker, were low-pass filtered at 2, 3, 4, 5, 6, and 9 kHz. Frequency shaping was provided for the hearing-impaired subjects only. Results revealed significant differences in recognition between the four groups of subjects. Specifically, both groups of children performed more poorly than their adult counterparts at similar bandwidths. Likewise, both hearing-impaired groups performed more poorly than their normal-hearing counterparts. In addition, significant talker effects for /s/ were observed. For the male talker, optimum performance was reached at a bandwidth of approximately 4-5 kHz, whereas optimum performance for the female and child talkers did not occur until a bandwidth of 9 kHz.

Recognition of speech produced in noise

A two-part study examined recognition of speech produced in quiet and in noise by normal hearing adults. In Part I 5 women produced 50 sentences consisting of an ambiguous carrier phrase followed by a unique target word. These sentences were spoken in three environments: quiet, wide band noise (WBN), and meaningful multi-talker babble (MMB). The WBN and MMB competitors were presented through insert earphones at 80 dB SPL. For each talker, the mean vocal level, long-term average speech spectra, and mean word duration were calculated for the 50 target words produced in each speaking environment. Compared to quiet, the vocal levels produced in WBN and MMB increased an average of 14.5 dB. The increase in vocal level was characterized by increased spectral energy in the high frequencies. Word duration also increased an average of 77 ms in WBN and MMB relative to the quiet condition. In Part II, the sentences produced by one of the 5 talkers were presented to 30 adults in the presence of multi-talker babble under two conditions. Recognition was evaluated for each condition. In the first condition, the sentences produced in quiet and in noise were presented at equal signal-to-noise ratios (SNR(E)). This served to remove the vocal level differences between the speech samples. In the second condition, the vocal level differences were preserved (SNR(P)). For the SNR(E) condition, recognition of the speech produced in WBN and MMB was on average 15% higher than that for the speech produced in quiet. For the SNR(P) condition, recognition increased an average of 69% for these same speech samples relative to speech produced in quiet. In general, correlational analyses failed to show a direct relation between the acoustic properties measured in Part I and the recognition measures in Part II.

Child maltreatment: risk of adjustment problems and dating violence in adolescence

OBJECTIVE

To examine the relationship between child maltreatment, clinically relevant adjustment problems, and dating violence in a community sample of adolescents.

METHOD

Adolescents from 10 high schools (N= 1,419; response rate = 62%) in southwestern Ontario completed questionnaires that assessed past maltreatment, current adjustment, and dating violence. Logistic regression was used to compare maltreated and nonmaltreated youths across outcome domains.

RESULTS

One third (n = 462) of the school sample reported levels of maltreatment above the cutoff score on the Childhood Trauma Questionnaire. Girls with a history of maltreatment had a higher risk of emotional distress compared with girls without such histories (e.g., odds ratios [OR] for anger, depression, anxiety, and posttraumatic stress-related problems were 7.1, 7.2, 9.3, and 9.8, respectively). They were also at greater risk of violent and nonviolent delinquency (OR = 2.7) and carrying concealed weapons (OR = 7.1). Boys with histories of maltreatment were 2.5 to 3.5 times as likely to report clinical levels of depression, posttraumatic stress, and overt dissociation as were boys without a maltreatment history. They also had a significantly greater risk of using threatening behaviors (OR = 2.8) or physical abuse (OR = 3.4) against their dating partners.

CONCLUSIONS

Maltreatment is a significant risk factor for adolescent maladjustment and shows a differential pattern for male and female adolescents.

Perception of voiceless fricatives by normal-hearing and hearing-impaired children and adults

This study examined the perceptual-weighting strategies and performance-audibility functions of 11 moderately hearing-impaired (HI) children, 11 age-matched normal-hearing (NH) children, 11 moderately HI adults, and 11 NH adults. The purpose was to (a) determine the perceptual-weighting strategies of HI children relative to the other groups and (b) determine the audibility required by each group to achieve a criterion level of performance. Stimuli were 4 nonsense syllables (see text). The vowel, transition, and fricative segments of each nonsense syllable were identified along the temporal domain, and each segment was amplified randomly within each syllable during presentation. Point-biserial correlation coefficients were calculated using the amplitude variation of each segment and the correct and incorrect responses for the corresponding syllable. Results showed that for /see text/ and /see text/, all four groups heavily weighted the fricative segments during perception, whereas the vowel and transition segments received little or no weight. For /see text/, relatively low weights were given to each segment by all four groups. For /see text/, the NH children and adults weighted the transition segment more so than the vowel and fricative segments, whereas the HI children and adults weighted all three segments equally low. Performance-audibility functions of the fricative segments of /see text/ and /see text/ were constructed for each group. In general, maximum performance for each group was reached at lower audibility levels for /see text/ than for /see text/ and steeper functions were observed for the HI groups relative to the NH groups. A decision theory approach was used to confirm the audibility required by each group to achieve a > or =90% level of performance. Results showed both hearing sensitivity and age effects. The HI listeners required lower levels of audibility than the NH listeners to achieve similar levels of performance. Likewise, the adult listeners required lower levels of audibility than the children, although this difference was more substantial for the NH listeners than for the HI listeners.

The relation between stimulus context, speech audibility, and perception for normal-hearing and hearing-impaired children

In this study, the influence of stimulus context and audibility on sentence recognition was assessed in 60 normal-hearing children, 23 hearing-impaired children, and 20 normal-hearing adults. Performance-intensity (PI) functions were obtained for 60 semantically correct and 60 semantically anomalous sentences. For each participant, an audibility index (AI) was calculated at each presentation level, and a logistic function was fitted to rau-transformed percent-correct values to estimate the SPL and AI required to achieve 70% performance. For both types of sentences, there was a systematic age-related shift in the PI functions, suggesting that young children require a higher AI to achieve performance equivalent to that of adults. Improvement in performance with the addition of semantic context was statistically significant only for the normal-hearing 5-year-olds and adults. Data from the hearing-impaired children showed age-related trends that were similar to those of the normal-hearing children, with the majority of individual data falling within the 5th and 95th percentile of normal. The implications of these findings in terms of hearing-aid fitting strategies for young children are discussed.

Recognition performance for four combinations of FM system and hearing aid microphone signals in adverse listening conditions

OBJECTIVE

Children with moderate to severe hearing loss routinely use personal frequency modulated (FM) systems in the classroom to improve the signal to noise ratio of teacher-directed speech with notable success. Attention is now being given to the ability of these children to hear other students via the hearing aid (HA) microphone while using an FM system. As a result, a variety of FM system and HA microphone combinations have been recommended for classroom use. To date, there are no studies regarding the efficacy of these FM/HA combinations. The purpose of this study was to evaluate recognition performance using four FM/HA combinations and to characterize that performance for stimuli received primarily through FM system and HA microphone transmission.

DESIGN

Recognition performance for FM system and HA microphone signals was evaluated for two symmetrical and two asymmetrical FM/HA combinations using two commercially available FM systems (one conventional and one FM-precedence circuit). Eleven children (ages 9 to 12) with moderate to severe sensorineural hearing loss and eight children (ages 10 to 11) with normal hearing served as subjects. The two symmetrical FM/HA combinations included: 1) binaural FM system and HA microphone input using the conventional FM system, and 2) binaural FM and HA input using the FM-precedence circuit. The conventional FM system was used for the two asymmetrical combinations and included: 1) binaural FM input and monaural HA input, and 2) FM input to one ear and HA input to the other. Stimuli were 33 consonants presented in the form of nonsense syllables. The stimuli were presented through three loudspeakers representing a teacher and two fellow students in a classroom environment. Speech shaped noise was presented through two additional loudspeakers.

RESULTS

In general, no statistically significant differences in recognition performance were found between any of the FM/HA combinations. Mean recognition scores for HA microphone transmission (55%) were significantly poorer than those for FM system transmission (75%). As expected, initial consonants were more easily recognized than final consonants via FM system and HA microphone transmission. However, voiceless consonants were more easily recognized than voiced consonants via HA microphone transmission, which was not predicted on the basis of previous research.

CONCLUSIONS

These results suggest that a certain amount of flexibility is present when choosing an FM/HA combination. However, recognition performance via the HA microphones was consistently poorer than performance via FM transmission. Because relevant material also originates from fellow students (e.g., answering teacher-directed questions), input via the HAs is often as important as information originating from the teacher. The results suggest that attempts to improve performance for signals transmitted through the HA microphones in a classroom setting would benefit children with hearing loss.

Evaluation of the antigenicity and reactogenicity of varying formulations of the rhesus rotavirus-based quadrivalent and the M37 rotavirus vaccine candidates

Three phase I trials of the rhesus rotavirus (RRV)-based quadrivalent vaccine [composed of serotype 3 (RRV), and serotypes 1 (D x RRV), 2 (DS1 x RRV), and 4 (ST3 x RRV) human rotavirus x RRV reassortants] and the M37 (nursery strain) rotavirus vaccine candidates were conducted in an attempt to find a safe and optimally antigenic formulation. Infants 10-20 weeks old received, in trial I, 1) the quadrivalent vaccine as two separate bivalent doses (1 x 10(4) PFU each of D x RRV and RRV, followed 4 weeks later by 1 x 10(4) PFU each of DS1 x RRV and ST3 x RRV) or 2) placebo; in trial II, 1) one dose of quadrivalent vaccine (10(4) PFU of each component), or 2) two doses of quadrivalent vaccine, or 3) a 10(4) PFU dose of M37 vaccine, or 4) M37 vaccine followed by the quadrivalent vaccine, or 5) placebo; in trial III, 1) a dose of a higher-titered quadrivalent vaccine (10(5) PFU of each component), or 2) two doses of higher titered quadrivalent vaccine, or 3) a dose of higher titered M37 vaccine (10(5) PFU) or 4) two doses of M37 vaccine (10(5) PFU), or 5) M37 vaccine (10(5) PFU) followed by the higher titered quadrivalent vaccine, or 6) placebo. A mild, transient fever during the first week postvaccination was associated with the bivalent or quadrivalent vaccines but not with the M37 vaccine. Fourfold or greater serum IgA ELISA responses to rotavirus were observed in 48-92% of the infants receiving quadrivalent vaccine and in 32-50% of those receiving M37 vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Reactogenicity and immunogenicity of a high-titer rhesus rotavirus-based quadrivalent rotavirus vaccine

We evaluated the reactogenicity and antigenicity of a quadrivalent rotavirus vaccine composed of serotype 3 rhesus rotavirus (RRV) and three single-gene-substitution reassortants of RRV and human strain D (D x RRV, serotype 1), DS1 (DS1 x RRV, serotype 2), or ST3 (ST3 x RRV, serotype 4) in a double-masked study with 302 infants in Caracas, Venezuela. Three doses of the quadrivalent vaccine composed of either 10(5) PFU (low titer) or 10(6) PFU (high titer) of each component were administered to 99 and 101 infants, respectively, at 4-week intervals starting at the second month of age; 102 infants received a placebo. Postvaccination reactions were monitored by home visits every other day during the week postvaccination. The vaccine was associated with the occurrence of mild, short-lived febrile episodes in 26 and 23% of the recipients after the first doses of high- or low-titer vaccine, respectively, in comparison with 13% of the infants receiving the placebo. Febrile reactions occurred less frequently in vaccinees after the second or third dose than after the initial dose. The vaccine was not significantly associated with diarrhea or any additional symptom or sign. Serum specimens obtained shortly before the first, 4 weeks after the first, and 4 weeks after the third dose of vaccine or placebo were tested by an immunoglobulin A enzyme-linked immunosorbent assay and by neutralization assays. Seroresponses occurred significantly more often after 3 doses than after a single dose of either vaccine. Immunoglobulin A responses were observed in 80 and 79% of the infants after 3 doses of high- or low-titer vaccine, respectively. Most of the infants tested developed a neutralization response to RRV after 3 doses of the high- (90%) or low-(88%) titer vaccine. Neutralization response rates to human rotavirus serotypes 1 to 4 after 3 doses were similar in both vaccine and 87 of 90 receiving the high-titer vaccine developed seroresponses, as detected by any of the assays employed. The study indicates that 3 doses of quadrivalent vaccine at a titer of 10(6) PFU of each component offered no advantage over the lower-titer preparation for use in efficacy trials.

Direct isolation in cell culture of human rotaviruses and their characterization into four serotypes

Of 73 rotavirus-positive fecal specimens tested, 39 yielded a human rotavirus that could be cultivated serially in MA104 or primary African green monkey kidney cells or both; 18 were serotyped. Four distinct serotypes were identified by plaque reduction or tube neutralization assay or both, and three of these serotypes were the same as those established previously by plaque reduction, using human rotaviruses cultivated by genetic reassortment with a cultivable bovine rotavirus. Ten human rotavirus strains received from Japan were found to be similar, if not identical, to our candidate prototype strains representing these four human rotavirus serotypes.

Definition of human rotavirus serotypes by plaque reduction assay

Twenty different human rotavirus reassortants were characterized serologically by a plaque reduction assay as belonging to one of three distinct serotypes. Fourteen were similar if not identical to our prototype Wa strain; two were like the prototype DS-1 strain, and four belonged to a third serotype for which a prototype has not yet been selected. Hyperimmune sera raised against the three serotypes were required to distinguish among them, since postinfection sera had lower titers and were more cross-reactive than hyperimmune sera. These results confirmed the ability of a qualitative cytopathic neutralization test to predict correctly the Wa or DS-1 serotype. A strain of rhesus rotavirus (MMU 18006) was identified as belonging to the newly defined third serotype. Finally, an attempt was made to correlate previously published serotype analysis by neutralization of fluorescent cell-forming units with the results determined by the plaque reduction neutralization assay.