Preliminary evidence for persistent abnormalities in amygdala volumes in adolescents and young adults with bipolar disorder

OBJECTIVES

Abnormalities in volumes of the amygdala have been reported previously in adolescents and adults with bipolar disorder (BD). Several studies have reported reduced volumes in adolescents with BD; however, both decreases and increases in volumes have been reported in adults with BD. Understanding of potential developmental contributions to these disturbances in morphology of the amygdala has been limited by the absence of longitudinal data in persons with BD. Here we use a within-subject longitudinal design to investigate whether amygdala volume abnormalities persist in adolescents and young adults with BD over a time interval of approximately 2 years.

METHODS

Participants included 18 adolescents and young adults: 10 participants with BD I and 8 healthy comparison participants. Amygdala volumes were measured on high-resolution magnetic resonance imaging scans acquired twice for each subject over intervals of approximately 2 years. Amygdala volumes were the dependent measures in a mixed-model statistical analysis to compare amygdala volumes between groups over time while covarying for total brain volume.

RESULTS

Amygdala volumes were significantly smaller in adolescents and young adults with BD compared with healthy participants (p = 0.018). The effect of time was not significant.

CONCLUSIONS

Although the sample size is modest, this study provides preliminary evidence to support the presence of decreased amygdala volumes in adolescents and young adults with BD that persist during this developmental epoch.

195REMOVAL OF EQUINE ARTERITIS VIRUS FROM STALLION SEMEN

Infection of breeding horses with equine arteritis virus (EAV) can result in abortion in up to 50% of mares (Del Piero F 2000 Vet. Pathol. 37, 287–296). Viral transmission occurs in body fluids, including semen (Golnik W et al. 1986 Zentralblatt für Veterinarmedizin 33, 413–417), with infected males potentially shedding virus indefinitely. Previously, the only means of preventing EAV transmission via semen was to remove identified shedders from the breeding pool. Recent medical studies have shown that viral infectivity can be removed from the semen of HIV or hepatitis C patients by a sequential method of sperm preparation: i.e. centrifugation on a discontinuous density gradient, followed by swim-up, (e.g. Bujan et al. 2002 Fertil. Steril. 78, 1321–1323; Levy et al. 2002 Hum. Rep. 17, 2650–2653). Human sperm prepared by this method have been used in over 1000 assisted reproduction attempts without sero-conversion of mothers or children (Lyerly A et al. 2001 Fertil. Steril. 75, 843–858). The current study investigates whether a sequential preparation technique of centrifugation on an EquiPure density gradient followed by a swim-up into a sperm maintenance medium can remove EAV from stallion ejaculates. Aliquots (1mL) of stallion semen, extended in Kenny’s medium, were spiked with known quantities of EAV at three levels corresponding to 1.0, 10 and 100 TCID50/mL−1. The latter was considered to be representative of levels seen in natural infection (Timoney PJ et al. 1987 J. Reprod. Fertil. (Suppl. 35), 95–102). Aliquots of spiked semen were prepared by centrifugation on EquiPure gradients. After centrifuging the resulting sperm pellets in EquiSperm Wash, the sperm were subjected to a swim-up treatment (all sperm preparation material from NidaCon, Gothenburg, Sweden). Aliquots of the sperm preparations, the unspiked extended semen, and spiked extended semen were stored at −70°C for viral assay by nested PCR (Belak S et al. 1994 Proc. 7th Int. Conf. Equine Inf. Dis. pp 33–38). The sensitivity of this assay is less than 1 PFU mL−1 of virus in seminal plasma, as validated by Belak et al. Using the PCR technique, a region from the nucleocapsid gene of EAV is amplified, resulting in a 170-base-pair product. Details of the primer sequences used are as follows: first TCGATGGCGTCAAGACGATCAC and GGTTCCTGGGTGGCTAATAACTACTTCAAC; second CGCAACCCACTCAGGCTATTATTG and GGTAGGAACCCAACTGACGGTG. The untreated spiked samples were all positive for EAV, whereas the sperm preparations from the spiked semen, after density gradient and swim-up, were negative for EAV. A negative control (water) and the unspiked extended ejaculate were also negative. These preliminary results indicate that the sequential technique of centrifugation on an EquiPure density gradient followed by a swim-up is potentially a useful and simple tool for the removal of EAV from the semen of shedding stallions. Further experiments will investigate whether the virus can be removed from naturally infected ejaculates. We are grateful to Prof. Twink Allen and Miss Clare Tiplady of the Equine Fertility Unit, Newmarket, UK, for providing samples of stallion semen. This study is partially funded by Eureka (E-2967).

T cells are required for host protection against Brugia malayi but need not produce or respond to interleukin-4

T cells are known to be required for host protection in mouse models of Brugia malayi infection. Several independent studies in murine models have also highlighted the rapid induction of Th2-like responses after infection with B. malayi or B. pahangi. Previous data from our laboratory have described a significant increase in permissiveness in the absence of interleukin-4 (IL-4), the "prototypical" Th2 cytokine, involved in both the induction and maintenance of Th2 responses. These observations led to our hypothesis that T cells involved in murine host protection would respond to IL-4 signaling and differentiate into cells of the "type 2" phenotype. As such, these cells would presumably also act as major sources of IL-4. To investigate these hypotheses, we performed several adoptive transfers in which we controlled the cell population(s) able to produce or respond to IL-4. We show here that, in contrast to our original hypotheses, IL-4 production and IL-4 receptor expression by T cells are both dispensable for T-cell-mediated host protection. Instead, our data imply that T cells may be required for eosinophil accumulation at the site of infection.

Histopathologic and histochemical characterization of calcified structures in hamsters inoculated with Paracoccidioides brasiliensis

In pathogenicity studies of 31 Paracoccidioides brasiliensis isolates preserved using Castellani's method we intraperitoneally inoculated 104 young adult hamsters and found laminated concentric structures and calcified appearance that resembled Schaumann bodies, in 43 of them, especially in animals with apparently good condition. We characterized these structures histologically and histochemically using different stains (PAS, Grocott, haematoxylin-eosin, Von Kossa). The Von Kossa staining revealed calcium in these structures. Similar structures have been described in patients with sarcoidosis and also in hamsters inoculated with P. brasiliensis. We found no correlation between the presence of these calcifications and serum calcium levels.

THE POTENTIAL FOR GEOLOGICAL SEQUESTRATION OF CO2 IN AUSTRALIA: PRELIMINARY FINDINGS AND IMPLICATIONS FOR NEW GAS FIELD DEVELOPMENT

Many industries and researchers have been examining ways of substantially reducing greenhouse gas emissions. No single method is likely to be a panacea, although some options do show considerable promise. Geological sequestration is one option that utilises mature technology and has the potential to sequester large volumes of CO2. This technology may have particular relevance to some of Australia’s major gas resources that are relatively high in CO2. In Australia, geological sequestration has been the subject of research within the Australian Petroleum Cooperative Research Centre’s GEODISC program. A portfolio of potential geological sequestration sites (sinks) has been identified across all sedimentary basins in Australia, and these have been compared with nearby known or potential CO2 emission sources, including natural gas resources. These sources have been identified by incorporating detailed analysis of the national greenhouse gas emission databases with other publicly available data, a process that resulted in recognition of eight regional emission nodes. An earlier generic economic model for geological sequestration in Australia has been updated to accommodate the changes arising from this process of source to sink matching. Preliminary findings have established the relative attractiveness of potential injection sites through a ranking approach. It includes the ability to accommodate the volumes of sequesterable greenhouse gas emissions predicted for the adjacent region, the costs involved in transport, sequestration and ongoing operations, and a variety of technical geological risks. Some nodes with high volumes of emissions and low sequestration costs clearly appear to be suitable, whilst others with technical and economic issues appear to be problematic. This assessment may require further refinement once findings are completed from the GEODISC site-specific research currently underway.

Interleukin-4 receptor-Stat6 signaling in murine infections with a tissue-dwelling nematode parasite

Interleukin-4 (IL-4) has been shown to be crucial in parasite expulsion in several gastrointestinal nematode infection models. Data from both epidemiological studies with humans and experimental infections in animals imply a critical role for the type II helper response, dominated by IL-4, in host protection. Here we utilized inbred mice on two distinct backgrounds to document the involvement of IL-4 in the clearance of a primary infection of Brugia from the murine host. Our data from infections of IL-4 receptor(-/-) and Stat6(-/-) mice further indicate that IL-4 exerts its effects by activating the Stat6 molecule in host target cells, a finding which links clearance requirements of a gastrointestinal tract-dwelling nematode with those of a tissue-dwelling nematode. Additionally, we show that the requirements for IL-4 receptor binding and Stat6 activation extend to accelerated clearance of a secondary infection as well. The data shown here, including analysis of cell populations at the site of infection and infection of immunoglobulin E (IgE)(-/-) mice, lead us to suggest that deficiencies in eosinophil recruitment and isotype switching to IgE production may be at least partially responsible for slower parasite clearance in the absence of IL-4.

Might patients benefit from oral iron therapy following operative treatment of breast carcinoma?

AIMS

To assess the changes in blood haemoglobin concentration and serum iron indices as a consequence of breast operations for cancer in our unit.

METHODS

Haematological parameters were measured in 109 patients undergoing definitive operative treatment for breast carcinoma.

RESULTS

A mean fall in haemoglobin of 2.1 g (P=0.001) occurred in patients undergoing mastectomy and axillary clearance and of 1.3 g (P<0.001) in patients undergoing wide local excision and axillary clearance. The transferrin saturation (serum iron/total iron binding capacity) in both sets of patients after surgery fell on average to levels that would be expected to impair subsequent red cell production.

CONCLUSION

The changes in iron indices that occurred were unrelated to the degree of blood loss consistent with a possible inflammatory effect of the operation. Oral iron therapy is unlikely to be of benefit to operative breast patients if they have normal pre-operative iron stores.

Palliative care in the community for children with cancer in South East England

In-depth interviews and discussions were held with 40 different professionals in South East England involved in managing palliative care for children with cancer in the community. Participants included paediatric oncologists and outreach nurse specialists in tertiary centres, paediatricians in shared care units, children's community nurses, general practitioners, social workers and child psychologists. The research examined palliative care services available in the region, exploring attitudes to both current provision and possible service improvements. Providing palliative care in the community involves multi-agency collaboration and the study highlighted a range of different approaches to case management with the diversity of resources available. Key improvements proposed by health-care professionals included: better communication and liaison between all the professionals involved; clearer allocation of roles and responsibilities; 24-hour availability of specialist advice on palliative care for children with cancer; faster access to social work and psychology services at the community level; continuity of nursing and respite care. The provision of specialist local palliative care services for children with cancer was generally rejected. The participants favoured improving community palliative care for all children with life-limiting or life-threatening conditions with community nursing teams providing continuity of care and outreach nurses providing specialist advice and support.

Invasive serotype a Haemophilus influenzae infections with a virulence genotype resembling Haemophilus influenzae type b: emerging pathogen in the vaccine era?

OBJECTIVE

Haemophilus influenzae type b causes severe disease in nonimmune infants and young children; other serotypes are uncommon pathogens and thought to have low virulence. Some have hypothesized that with the virtual elimination of H influenzae type b, other serotypes might acquire virulence traits and emerge as important pathogens of children. We describe the clinical, epidemiologic, and molecular biologic features of 5 cases of severe disease attributable to Haemophilus influenzae type a.

METHODS

After observing 4 cases of invasive disease caused by H influenzae type a, we reviewed microbiology records at 3 reference laboratories that perform all serotyping in Utah and surveillance databases. Strains of H influenzae type a and control strains were examined by Southern blotting with the use of the cap probe pUO38 and by pulsed-field gel electrophoresis. The putative virulence mutation, the IS1016-bexA deletion, was detected by polymerase chain reaction amplification and sequencing.

RESULTS

During a 10-month period, we observed 5 children with severe invasive disease caused by H influenzae type a. No isolates of H influenzae type a had been submitted to the reference laboratories between 1992 and 1998. The median age of patients was 12 months (range: 6-48 months). Four of 5 had meningitis and bacteremia; 1 had purpura fulminans. Three isolates, representing 1 of 2 pulsed-field gel electrophoresis patterns, contained the IS1016-bexA deletion and were associated with particularly severe disease.

CONCLUSIONS

We describe an unusual cluster of severe disease caused by H influenzae type a that resembles the clinical and epidemiologic features of H influenzae type b disease. Our data support the hypothesis that the IS1016-bexA deletion may identify more virulent strains of H influenzae. Haemophilus influenzae, epidemiology, virulence, serotyping, pathogenicity.

Primary health care for Hispanic children of migrant farm workers

Providing primary care to children of culturally diverse populations is a challenge for pediatric nurse practitioners and educators. The challenge is intensified when providing care to Hispanic children who are uprooted because their parent(s) are migrant farm workers. The creation of health-focused academic community partnerships is one unique strategy to improve primary care to these children. One such partnership is the ongoing Migrant Family Health Program in which practitioner nursing students and their faculty members provide primary health care to children who are enrolled in a summer education program for migrant children.

Thrombospondin-1 suppresses wound healing and granulation tissue formation in the skin of transgenic mice

The function of the endogenous angiogenesis inhibitor thrombospondin-1 (TSP-1) in tissue repair has remained controversial. We established transgenic mice with targeted overexpression of TSP-1 in the skin, using a keratin 14 expression cassette. TSP-1 transgenic mice were healthy and fertile, and did not show any major abnormalities of normal skin vascularity, cutaneous vascular architecture, or microvascular permeability. However, healing of full-thickness skin wounds was greatly delayed in TSP-1 transgenic mice and was associated with reduced granulation tissue formation and highly diminished wound angiogenesis. Moreover, TSP-1 potently inhibited fibroblast migration in vivo and in vitro. These findings demonstrate that TSP-1 preferentially interfered with wound healing-associated angiogenesis, rather than with the angiogenesis associated with normal development and skin homeostasis, and suggest that therapeutic application of angiogenesis inhibitors might potentially be associated with impaired wound vascularization and tissue repair.

Hepatitis B immunity in high risk health care workers. Seven years post vaccination

The purpose of this descriptive, quantitative study was to examine hepatitis B immunity in high risk health care workers 7 years post immunization. The study related immunity to age and site of injection, and also described titer results. The study sample was composed of 42 health care workers from areas with frequent blood exposure. The study found that 21% of the health care workers had nonreactive titers 7 or more years post immunization. No significant differences existed in the percentages of the reactive participants according to injection site, although it is recommended the injection be given intramuscularly in the deltoid. No statistically significant relationship was revealed by comparing titer results to age. The low power (.24) displays the need for larger sample sizes which could be obtained by using multicenter data sites. Future research with national collaboration and standard performance measurement systems could provide crucial information related to hepatitis B immunity in health care workers.

What's best? Clinical indicators of quality in residential aged care facilities

This paper reports on the views of 36 registered nurses (RNs) in Phase One of a three stage study, Quality of Care for Residents in Aged Care Facilities. Case studies were conducted in nine residential aged care facilities and data were collected from informants using semi-structured interviews, participant observation and document analysis and review. Of the 36 RNs, almost three quarters (n=26) provided care at the bedside and ten held managerial positions. Each volunteered to participate. When asked to nominate the major clinical indicators of high quality residential aged care, all 26 RNs who worked at the bedside stated that the absence of decubitis ulcers was the pre-eminent measurable factor. While five managerial RNs also mentioned low rates of pressure ulcers, only two ranked it as the most important clinical indicator of high quality care. Hydration management was the clinical indicator nominated most frequently by managerial nurses. The one indicator of equal importance to both groups, but for different reasons, was that of poly pharmacy. The differences in priorities between each group were statistically significant.

Reactivity of ferulic acid and its derivatives toward hydrogen peroxide and peracetic acid

The reactions of ferulic acid and its derivatives with hydrogen peroxide and peracetic acid in lignin-retaining bleaching conditions have been investigated to determine their susceptibility to oxidative degradation. The conjugated side chain of ferulic acid and its etherified or esterified derivative was shown to be fairly stable, especially to hydrogen peroxide. The major reaction was trans-cis isomerization that possibly involved a radical mechanism but did not cause bond cleavage. The peracetic acid reaction increased the rate of trans-cis isomerization and was also accompanied by a minor cleavage of the side chain. Esterification did not have a substantial effect on the reactivity of ferulic acid, but 4-O-etherification significantly stabilized it against these two oxidants. By contrast, aldehyde substitution tremendously enhanced the susceptibility of the cinnamyl side chain to oxidative degradation, as evidenced by an intensive degradation of coniferaldehyde.

A comparison of language achievement in children with cochlear implants and children using hearing aids

English language achievement of 29 prelingually deaf children with 3 or more years of cochlear implant (CI) experience was compared to the achievement levels of prelingually deaf children who did not have such CI experience. Language achievement was measured by the Rhode Island Test of Language Structure (RITLS), a measure of signed and spoken sentence comprehension, and the Index of Productive Syntax (IPSyn), a measure of expressive (signed and spoken) English grammar. When the CI users were compared with their deaf age mates who contributed to the norms of the RITLS, it was found that CI users achieved significantly better scores. Likewise, we found that CI users performed better than 29 deaf children who used hearing aids (HAs) with respect to English grammar achievement as indexed by the IPSyn. Additionally, we found that chronological age highly correlated with IPSyn levels only among the non-CI users, whereas length of CI experience was significantly correlated with IPSyn scores for CI users. Finally, clear differences between those with and without CI experience were found by 2 years of post-implant experience. These data provide evidence that children who receive CIs benefit in the form of improved English language comprehension and production.

Listening to migrant voices: focus groups on health issues in south Georgia

This qualitative study utilized focus groups to invite Latino migrant farm workers to express ideas about their health and service needs. Four focus groups composed of Latino men and women were conducted on four different evenings in the same county. Three themes emerged: health care issues, living and working conditions, and social and community issues. Specific needs of the community were also identified by the participants. For the first time, migrant farm workers in Georgia had the opportunity to lend their own voice regarding their concerns and ideas about health and social conditions. The findings from this study are congruent with other studies and provide the basis for developing interventions to enhance the health of migrant farm workers. In addition, the findings have implications for community health nursing and the proposed Vision of 2010: Healthy People in Healthy Communities, whose goals include increased years of healthy life and the elimination of health disparities.

A pilot study of MVP (mitomycin-C, vinblastine and cisplatin) chemotherapy in small-cell lung cancer

MVP chemotherapy (mitomycin C 8 mg m(-2), courses 1, 2, 4 and 6, vinblastine 6 mg m(-2), cisplatin 50 mg m(-2)) is an active low-toxicity regimen in non-small-cell lung cancer (NSCLC). Based on the single-agent activity of these agents in SCLC, we have conducted a phase II trial of MVP in SCLC. Fifty chemo-naive patients with SCLC were entered in this trial. There were 33 men and 17 women with median age 66 years (range 46-83 years); 18 patients had limited disease (LD) and 32 extensive disease (ED). WHO performance status (PS) was: three patients PS 0, 33 patients PS 1, ten patients PS 2, four patients PS 3. A maximum of six cycles was given in responding patients. On completion of chemotherapy, patients with LD obtaining complete response (CR)/good partial response (PR) received thoracic irradiation and those obtaining CR were offered entry into the ongoing MRC Prophylactic Cranial Irradiation Trial. The overall response was 79% with 17% CR and 62% PR. For LD patients, 38% obtained CR but for ED only one patient achieved CR. Median response duration for LD patients was 8 months and for ED patients 5 months. Median survival was 10 months for LD patients and 6 months for ED patients. There was complete resolution of symptoms in 24%, partial improvement in 68%, no change in 2% and progressive symptoms in 6%. As regards toxicity, 24% developed WHO grade 3/4 neutropenia, 16% grade 3/4 thrombocytopenia and 6% significant hair loss. Two patients died during the first week of treatment with neutropenic infection. Quality of life using the EORTC questionnaire (QLC-C30) with lung cancer module demonstrated significant improvements from baseline levels in emotional and cognitive functioning, global QOL, of pain, dyspnoea and cough. MVP, an effective palliative regimen for NSCLC, is also active against SCLC with low toxicity and merits comparison with more toxic conventional schedules.

Good symptom relief with palliative MVP (mitomycin-C, vinblastine and cisplatin) chemotherapy in malignant mesothelioma

PURPOSE

To evaluate the therapeutic impact of a simple combination chemotherapy regimen on symptoms related to malignant mesothelioma.

MATERIALS AND METHODS

Between October 1986 and June 1997, 39 patients with advanced inoperable malignant mesothelioma were treated with palliative MVP (mitomycin-C 8 mg/m2 q. six weeks, vinblastine 6 mg/m2 q. three weeks and cisplatin 50 mg/m2 q. three weeks) chemotherapy and assessed for objective response and relief of symptoms.

RESULTS

Eight of 39 patients (20%) achieved an objective partial response with a median duration of nine months: only five patients had progression of disease during chemotherapy. Twenty-four of 39 (62%) had an overall improvement in their symptomology with particularly good responses for pain (79%). These benefits were independent of performance status. Resolution of symptoms was achieved in all responding patients within two treatment cycles. There was no statistically significant difference in duration and incidence of symptom response in those patients achieving radiological PR compared with those with no change and more than 60% of patients with radiological no change obtained useful symptom control. The treatment was well tolerated with only four patients developing grade 3 leucopenia and three with grade 3 nausea.

CONCLUSIONS

MVP is a well tolerated regimen and its use in malignant mesothelioma provides useful symptomatic benefit. These results should be the basis for further trials of MVP in the management of mesothelioma with symptom control as a principal endpoint.

Hmong/medicine interactions: improving cross-cultural health care

BACKGROUND AND OBJECTIVES

There are now more than 100,000 Hmong (Southeast Asian) refugees in the United States. This study examined interactions between Hmong patients and their health care providers and identified specific factors that either enable or obstruct health care delivery.

METHODS

We used semistructured interview techniques to investigate patients' and providers' experiences, looking for attitudes, ideas, or behaviors that could be modified to improve health care delivery. Interviews with 23 Hmong patients, 18 health care providers, and six translators were audiotaped, transcribed, and analyzed by a multidisciplinary team. Methods included text analysis, theme identification, rank ordering, participant observation, immersion-crystallization, and open-ended discussion.

RESULTS

Hmong patients and their US-trained health care providers have different health belief systems. Both linguistic and cultural translation were seen as problematic. Additionally, an overwhelming number of patients identified kindness, caring, and a positive attitude as important provider characteristics. Providers noted difficulties in understanding Hmong conceptions of acute versus chronic diseases, illness prevention, and pain, both physical and psychological. Many respondents gave suggestions for improvement: 1) learn more about each other's cultures, 2) be patient, kind, and positive, 3) avoid negative statements or predictions, 4) improve translation quality, 5) explain medical terms using visual aids, 6) respect Hmong family-centered decision making, 7) increase the time allotted for translated clinical encounters, and 8) train Hmong health care providers.

CONCLUSIONS

Many basic issues in relations between clinicians and Hmong patients must be addressed to improve health care communication.

Reading Skills in Children with Multichannel Cochlear-lmplant Experience

Forty children with prelingual, profound deafness who received the Nucleus multichannel cochlear implant between the ages of 2 and 13 years participated in this study. The children had an average of 63.3 months (SD=24 months) of experience with their cochlear implants. A majority of the children used simultaneous communication and attended public-school programs at the time of testing. Reading achievement was assessed using the Paragraph Comprehension subtest of the Woodcock Reading Mastery Test-Revised, Form G (1987). This study compared the reading-achievement levels of this group of cochlear-implant users with the results of previous studies of children with profound hearing losses who did not have the benefit of cochlear implants. Results indicated that nearly one half of the children in this study were reading at or within 8 months of their grade level. The reading-grade quotient of .74 was calculated based upon the slope of the regression line for the plot of years in school and reading grade-level achieved. This finding indicates that using a cochlear implant has a positive effect on reading achievement level.

Differences in children's sound production when speaking with a cochlear implant turned on and turned off

Twenty children who have worn a Cochlear Corporation cochlear implant for an average of 33.6 months participated in a device-on/off experiment. They spoke 14 monosyllabic words three times each after having not worn their cochlear implant speech processors for several hours. They then spoke the same speech sample again with their cochlear implants turned on. The utterances were phonetically transcribed by speech-language pathologists. On average, no difference between speaking conditions on indices of vowel height, vowel place, initial consonant place, initial consonant voicing, or final consonant voicing was found. Comparisons based on a narrow transcription of the speech samples revealed no difference between the two speaking conditions. Children who were more intelligible were no more likely to show a degradation in their speech production in the device-off condition than children who were less intelligible. In the device-on condition, children sometimes nasalized their vowels and inappropriately aspirated their consonants. Their tendency to nasalize vowels and aspirate initial consonants might reflect an attempt to increase proprioceptive feedback, which would provide them with a greater awareness of their speaking behavior.

Phase I trial and tumour localisation of the anti-EGFR monoclonal antibody ICR62 in head and neck or lung cancer

The purpose of this study was to determine the effect of the first rat monoclonal antibody (MAb ICR62) to the epidermal growth factor receptor (EGFR) in a phase I clinical trial in patients with unresectable squamous cell carcinomas. This antibody effectively blocks the binding of EGF, transforming growth factor (TGF)-alpha and HB-EGF to the EGFR, inhibits the growth in vitro of tumour cell lines which overexpress the EGFR and eradicates such tumours when grown as xenografts in athymic mice. Eleven patients with squamous cell carcinoma of the head and neck and nine patients with squamous cell carcinoma of the lung, whose tumours expressed EGFR, were recruited. Groups of three patients were treated with 2.5 mg, 10 mg, 20 mg or 40 mg of ICR62 and a further eight patients received 100 mg. All patients were evaluated for toxicity using WHO criteria. Patients' sera were tested for the clearance of MAb ICR62 and the development of human anti-rat antibodies (HARA). No serious (WHO Grade III-IV) toxicity was observed in patients treated with up to 100 mg of antibody ICR62. Antibody ICR62 could be detected at 4 h and 24 h in the sera of patients treated with 40 mg or 100 mg of ICR62. Only 4/20 patients showed HARA responses (one at 20 mg, one at 40 mg and two at 100 mg doses) and of these only the former two were anti-idiotypic responses. In four patients receiving doses of ICR62 at 40 mg or greater, biopsies were obtained from metastatic lesions 24 h later and examined for the localisation of ICR62 using anti-rat antibody reagent. In these patients we showed the localisation of MAb ICR62 to the membranes of tumour cells; this appeared to be more prominent at the higher dose of 100 mg. On the basis of these data we conclude that MAb ICR62 can be administered safely to patients with squamous cell carcinomas and that it can localise efficiently to metastases even at relatively low doses.