Molecular interaction of CD1b with lipoglycan antigens

The ability of human CD1b molecules to present nonpeptide antigens is suggested by the T cell recognition of microbial lipids and lipoglycans in the presence of CD1b-expressing antigen-presenting cells. We demonstrate the high-affinity interaction of CD1b molecules with the acyl side chains of known T cell antigens, lipoarabinomannan, phosphatidylinositol mannoside, and glucose monomycolate. Furthermore, CD1b-antigen binding was optimal at acidic pH, consistent with the known requirement for endosomal acidification in CD1b-restricted antigen presentation. The mechanism for CD1b-ligand interaction involves the partial unfolding of the alpha helices of CD1b at acidic pH, revealing a hydrophobic binding site that could accommodate lipid. These data provide direct evidence that the CD1b molecule has evolved unique biochemical properties that enable the binding of lipid-containing antigens from intracellular pathogens.

Cytokine overproduction in healthy first degree relatives of patients with IDDM

Healthy family members of patients with insulin-dependent diabetes mellitus (IDDM) are known to share a number of immunological abnormalities with their affected relatives. Since monocyte and type 1 T-cell-derived cytokines contribute to the pathogenesis of IDDM, we studied the production of these cytokines in the healthy first degree relatives of 29 children with IDDM. We report that circulating tumour necrosis factor-alpha (TNF-alpha) and soluble interleukin-2 (sIL-2) receptor were present in increased amounts in non-diabetic family members at levels similar to those found in the diabetic children (duration of disease 3 months-5 years). Furthermore, marked hypersecretion of IL-1alpha and TNF-alpha by mitogen-stimulated peripheral blood mononuclear cells was found in both diabetic and healthy family members. Abnormalities of cytokine production in healthy relatives did not correlate with the presence of islet cell antibodies or with HLA DR type. These data indicate that healthy family members of patients with IDDM exhibit overproduction of a number of cytokines that have been implicated in diabetogenesis.

Multiplex sequencing of 1.5 Mb of the Mycobacterium leprae genome

The nucleotide sequence of 1.5 Mb of genomic DNA from Mycobacterium leprae was determined using computer-assisted multiplex sequencing technology. This brings the 2.8-Mb M. leprae genome sequence to approximately 66% completion. The sequences, derived from 43 recombinant cosmids, contain 1046 putative protein-coding genes, 44 repetitive regions, 3 tRNAs, and 15 tRNAs. The gene density of one per 1.4 kb is slightly lower than that of Mycoplasma (1.2 kb). Of the protein coding genes, 44% have significant matches to genes with well-defined functions. Comparison of 1157 M. leprae and 1564 Mycobacterium tuberculosis proteins shows a complex mosaic of homologous genomic blocks with up to 22 adjacent proteins in conserved map order. Matches to known enzymatic, antigenic, membrane, cell wall, cell division, multidrug resistance, and virulence proteins suggest therapeutic and vaccine targets. Unusual features of the M. leprae genome include large polyketide synthase (pks) operons, inteins, and highly fragmented pseudogenes.

AIDS dementia complex with generalized myoclonus

Focal and segmental, but not generalized, myoclonus have been described with human immunodeficiency virus (HIV) infection. We describe three patients with generalized myoclonus and acquired immunodeficiency syndrome (AIDS) dementia complex. In each, myoclonus persisted until death, invariably after a course of a few months. In two patients, myoclonus was elicited by sudden auditory stimuli and resembled a startle response. This form of myoclonus may be subcortical in origin. We suggest that the AIDS dementia complex be included among the causes of myoclonic dementia.

Urticaria and angioedema. A simple approach to a complex problem

Urticaria is a complex problem for both primary care practitioners and patients. Patients often present in considerable distress, with pruritus and uncomfortable lesions. They are frightened and frustrated about their condition and are searching for answers. Attempting to identify the cause by evaluating patient medications, contacts, and dietary history can be challenging. A multitude of laboratory tests can be performed, but they often do not provide a diagnosis. Skin allergy testing is frequently difficult at this stage. A working knowledge of the underlying pathology and causes of urticaria is essential during diagnosis. Astute evaluation can provide the clues necessary to accurately identify and treat the problem with available medications and modalities.

Febrile convulsions in selected large families: a single-major-locus mode of inheritance?

As part of a genetic linkage study of febrile convulsions, families with at least four members with the disorder were identified. By applying known principles of human inheritance, possible modes of transmission of febrile convulsions and factors which might impede progress in understanding their inheritance were analyzed. In eight families, 75 of 333 members had febrile convulsions. Inheritance of the disorder occurred in 43, 51, and 46% of children, siblings and all first-degree relatives of probands respectively. Vertical transmission occurred through three to four generations, including from male to male. In these families with multiple affected members, the findings support an autosomal dominant mode of inheritance of febrile convulsions.

Emotional support for cancer patients: what do patients really want?

For many cancer patients and their families the experience of cancer is an intensely stressful one. Emotional support is important for most cancer patients during their illness and can be gained from different people and services. This study evaluates patients' attitudes to different sources of support and rates their satisfaction with sources already used. A total of 431 patients completed a questionnaire covering the use of different sources, including individuals, support groups and information sources. The questionnaire also incorporated validated measurements of anxiety, depression and locus of control. The results revealed that the three most important sources of emotional support were senior registrars (73%) and family (73%), followed by consultants (63%). Patients would prefer doctor- and nurse-led support groups to patient only-led groups (26% vs 12%). Pamphlets, such as the BACUP booklets, proved the most important of the informational sources sought (50%). A total of 86% of patients were satisfied or very satisfied with the emotional support received. Patients who expressed dissatisfaction with their emotional support were significantly more likely to be anxious and depressed (P < 0.001). Patients who used information sources were more likely to have a higher locus of control over the course of their disease. These results show how important the doctor's role is in the provision of emotional support.

Mechanisms of murine RANTES chemokine gene induction by Newcastle disease virus

We have previously defined the lipopolysaccharide (LPS)-responsive element (LRE) in the promoters of murine RANTES (regulated on activation normal T-cell expressed) (MuRantes) and murine IP-10/crg-2, chemokines which have potent chemotactic properties for inflammatory cells including monocytes and T lymphocytes. In the present work, we studied the transcriptional mechanism of MuRantes gene induction by virus and compared it with that of LPS in an effort to understand the host responses to virus and bacterial toxins at the molecular level. MuRantes mRNA expression is induced by Newcastle disease virus (NDV) and LPS in the RAW 264.7 macrophage cell line and peritoneal macrophages of LPS-responsive C3HeB/FeJ mice. In LPS-hyporesponsive C3H/HeJ mice, only NDV induces this chemokine gene, indicating that the pathways of transcriptional activation by NDV and LPS are not identical. Using a transient transfection assay, the minimal virus-responsive element (VRE) was localized between nt -175 and -116. The VRE contains previously defined LRE motif 1 (TCAYRCTT) and motif 3 ((T/A)GRTTTCA(G/C)TTT), which were shown to also be important for initiation of transcription by virus. NDV-stimulated nuclear extracts were tested for trans-activating factors able to bind the VRE. The chromosomal protein HMG-I(C) was shown to bind the 3'-A.T-rich domains of the VRE, and the presence of HMG-I(C) was demonstrated in the VRE-protein complex formed with nuclear extracts from NDV-stimulated, but not unstimulated cells. These findings demonstrate the role of HMG-I(C) in activation of MuRantes promoter by NDV.

Mutant ras promotes haemopoietic cell proliferation or differentiation in a cell-specific manner

The ras gene products play a fundamental role in signal transduction in haemopoiesis. In this study, we have examined the effects of ras upon haemopoietic cell proliferation and differentiation, using two human cell lines which represent different stages of haemopoietic cell maturation. When a mutant H12-ras gene (codon 12: gly-->asp) was expressed in the monoblastic cell line, U937, marked inhibition of growth was seen together with morphological, functional and immunophenotypic evidence of monocytic maturation. Infection of U937 cells with a c-myc retrovirus produced similar changes strongly suggesting that Myc plays an important role in this action of Ras. By contrast, expression of H12-ras promoted factor-independent growth of the multipotent cell line, TF-1. Furthermore, mutant ras dramatically enhanced the growth of TF-1 cells in the presence of added GM-CSF or erythropoietin, but did not influence the state of differentiation of these cells. These data clearly indicate that in haemopoietic cells, Ras may promote either proliferation or differentiation depending upon cell type and/or state of maturation.

Febrile convulsions. Is seizure duration the most important predictor of temporal lobe epilepsy?

The association between febrile convulsions and temporal lobe epilepsy is recognized, but is controversial. We attempted to clarify this and to determine which attributes of febrile convulsions were associated with temporal lobe epilepsy. During a study of genetic linkage in febrile convulsions, families with at least four affected members were identified. Clinical features of febrile seizures and EEG findings were compared in those who did and did not develop later afebrile seizures. In six selected families, 59 family members had febrile convulsions. Temporal lobe epilepsy developed in eight of these, whereas only one of 213 family members with no febrile convulsions had temporal lobe epilepsy (P < 0.0001). The mean durations of febrile convulsions in those with and without progression to temporal lobe epilepsy were 100 and 9 min, respectively (P = 0.02). Five patients had temporal lobectomies, which revealed mesial temporal sclerosis in all cases. Four patients who developed other types of epilepsy had a mean duration of febrile convulsions of 90 min. The total number, the maximum number in any one day, and the age at onset of febrile convulsions did not differ significantly between groups. Only two patients had neurological deficits, both of whom subsequently had nonlocalizable partial epilepsy. In these families, selected to reduce genetic and phenotypic heterogeneity, a strong association was evident between febrile convulsions and temporal lobe epilepsy with mesial temporal sclerosis. A prolonged febrile convulsion was the most important determinant of this association.

Evidence for cell-specific differences in transformation by N-, H- and K-ras

Although Ras plays a fundamental role in cellular proliferation, differentiation and transformation, clear functional differences between the three major Ras proteins (N-, H- and K-Ras) have not as yet been demonstrated. In this study, chimeric constructs were used to compare directly transformation by N-, H- and K-ras oncogenes. In Rat-2 and NIH3T3 fibroblasts, transformation assays (anchorage independence, focus-formation and growth in 1% FCS) showed that H12-Ras was more transforming than N12-Ras or K12-Ras. By contrast, in the human multipotent haemopoietic cell line, TF-1, N12-Ras exhibited greater biological activity. Northern blotting and protein analyses indicated that these findings were not the result of differences in expression or stability of p21Ras. Using further H-ras/N-ras chimeric constructs, we found that the greater transforming activity of H12-Ras in fibroblasts was not due to the hypervariable-CAAX region, but rather to unique sequences between amino acids 84 and 143. These data demonstrate cell specific differences in the intrinsic transforming potential of N-ras, H-ras and K-ras oncogenes.

Selection of a highly enriched population of retrovirus-infected human hematopoietic progenitor cells using SNL fibroblasts

Retrovirus-mediated gene transfer into human hematopoietic progenitor cells for therapeutic or experimental purposes has proved difficult due to low and variable infection efficiency. To address this, we have developed an in vitro system for the selection and maintenance of a highly-enriched population of retrovirus-infected hematopoietic progenitor cells. Human umbilical cord CD34+ cells were cultured on SNL, a neo-containing murine fibroblast cell line used for embryonic stem cell culture. SNL-supported CD34+ cultures could be maintained with continuing blast cell and CFU-GM production for eight weeks, compared to four weeks in the absence of SNL. We then tested the ability of SNL to facilitate the selection in G418 of CD34+ cord cells infected with the neo-containing retrovirus, vsn-2. While all cells in the control cultures died within 14 days, vsn-2-infected CD34+ cells continued to proliferate, differentiate and produce CFU-GM for up to five weeks after infection. 100% of individually-plucked CFU-GM from such cultures were shown by PCR to be successfully infected. This approach should be useful for experimental work and, since it would diminish competitive repopulation between infected and uninfected progenitors, may also be utilized, with modification, for optimizing gene therapy protocols.

Neuromuscular disorders associated with failure to wean from the ventilator

OBJECTIVE

To determine, by retrospective chart analysis, the frequency, type and significance of neuromuscular disorders in patients whose clinical features suggested a neuromuscular cause of failure to wean.

BACKGROUND

Failure to wean is a common and difficult problem in critical care units. While a neuromuscular cause may be suspected in some patients, the frequency and type has not been determined utilizing comprehensive electrophysiological studies of limbs and the respiratory system. Such knowledge may aid in patient management and prognosis.

METHODS

The clinical setting was a critical care/trauma centre that admits 1500 patients per year, approximately 500 being on ventilators for longer than five days. We analyzed the hospital charts of 40 patients admitted to the unit during three years, whose respiratory assessment suggested a neuromuscular cause for failure to wean from the ventilator. To investigate this possibility, we performed electrophysiological studies of the limbs and also of the respiratory system by phrenic nerve conduction and needle electromyography of the chest wall and diaphragm. The results were compared to 25 healthy controls.

RESULTS

38 of 40 patients (95%) had a neuromuscular disorder: 25--critical illness polyneuropathy, 2--Guillain-Barré syndrome, 4--diabetic and critical illness polyneuropathy, 2--uremic and critical illness polyneuropathy, 10--an abnormality of central drive, 5--unilateral phrenic nerve palsy, 3--a neuromuscular transmission defect, and 5--a primary myopathy. Fifteen (38%) had a combination of disorders. Patients with more severe polyneuropathy took longer to wean, a mean of 136 versus 52 days (p = 0.007). The severity of the polyneuropathy had no effect on mortality.

CONCLUSIONS

Electrophysiological studies of limbs and the respiratory system are together valuable in confirming the presence, and identifying the specific type of neuromuscular cause for difficulty in weaning from the ventilator. This information is important in patient management and prognosis.

Helping homeless men begin a new life. A program on Chicago's West Side provides substance abuse rehabilitation and job training

The MARSEPH program, named for the two principal program collaborators--the Marillac Social Center and Saint Joseph Health Centers and Hospital--provides life and work skills to homeless men who visit a day shelter operated by the Marillac Social Center. Participants gain work experience at Saint Joseph. One of the most important aspects of the MARSEPH program is the removal of obstacles to the newly employed. Each MARSEPH participant receives housing assistance, a uniform, transportation to Saint Joseph Health Centers and Hospital, and a meal pass to the hospital's cafeteria. Through this assistance, the men can get off the streets, get to their jobs, be nourished, and look presentable. The MARSEPH program carefully monitors each participant's progress, to ensure his success. Case workers meet weekly with the men to discuss problems and concerns. Every week case workers also visit each participant's residence to monitor his living conditions and offer emotional support. At the end of the six-month training program, MARSEPH helps graduates find employment.

Occipital paroxysmal discharges suppressed by eye opening: variability in clinical and seizure manifestations in childhood

The EEG in childhood epilepsy with occipital paroxysms (CEOP) was termed "distinctive" by Gastaut (1985) and Talwar et al. (1992) and "characteristic" by Herranz Tanarro et al. (1984), which suggests that the EEG is specific and diagnostic for CEOP. However, this hypothesis has been challenged (Newton and Aicardi, 1983; Beaumanoir and Grandjean, 1987). To test this, we reviewed 5,291 EEG reports made in 5 1/2 years in the only tertiary pediatric center in Newfoundland and Labrador. We identified 31 children who had one or more EEGs with occipital spike/sharp waves showing suppression of discharges with eye opening and normal background activity. Six had CEOP, 17 had benign nocturnal childhood occipital epilepsy, 5 had symptomatic epilepsy, 3 had unusual complex partial seizures (CPS), 4 had only provoked seizures, and 2 had no definite seizures. Overlap between seizure types was common. The EEG criteria for CEOP are not very specific.

Evidence that ras and myc mediate the synergy between SCF or M-CSF and other haemopoietic growth factors

We previously reported that M-CSF could mimic the synergistic effect of SCF upon myeloid FDC-P1 cells that were first infected with a c-fms retrovirus, which encodes the human M-CSFr. We now report that an M-CSFr with a mutation of its autophosphorylation site at position 809 was, in response to M-CSF, unable both to synergize with IL-3 or GM-CSF and to induce c-myc; whereas a mutant receptor with a deletion of its kinase insert was unaffected for these processes. The expression of an exogenous c-myc proto-oncogene or a 12H-ras oncogene lowered the requirement of FDC-P1 cells for IL-3 or GM-CSF, in a similar manner to M-CSF or SCF addition. Furthermore, the expression of either of these genes complemented the defective M-CSFr F809. These results strongly support a role for ras and myc in the synergistic action of M-CSF and, by implication, of SCF, which implies that these signalling intermediates are rate-limiting for the action of IL-3 and GM-CSF and possibly other haemopoietic growth factors.

Retroviral-mediated gene transfer of a mutant H-ras gene into normal human bone marrow alters myeloid cell proliferation and differentiation

To investigate the effects of mutant ras expression on the growth and differentiation of normal human bone marrow, we used retrovirus-mediated gene transfer. A retrovirus (HR-1) containing a mutant ras gene (H12-ras) in addition to the selectable neo gene was transferred by cocultivation of a packaging cell line with long-term cultures of normal human bone marrow. Controls were established by cocultivating aliquots of the same bone marrow with a retrovirus (VSN-2) containing only neo. The efficiency of gene transfer, as determined by the percentage of G418-resistant colony-forming units-granulocyte/macrophage (CFU-GM) immediately after termination of cocultivation, was similar: 8 +/- 4% with HR-1 and 5 +/- 3% with VSN-2. After a further week in long-term culture, there was an increase in the number and percentage of G418-resistant CFU-GM in both the HR-1-infected and VSN-2-infected marrows. Thereafter, the numbers of G418-resistant CFU-GM declined, becoming undetectable at 4 weeks. The time course of the production of G418-resistant colonies was not significantly different in HR-1- and VSN-2-infected marrows, indicating that H12-ras did not alter the proliferation of normal CFU-GM. However, the total cellularity of HR-1-infected marrow cultures was significantly greater than that of VSN-2-infected marrow cultures. This was due to increased cellular proliferation of HR-1-infected cultured cells, since differential counts showed a significant increase in myeloid blast cells together with a slight reduction in mature myeloid cells in HR-1-infected marrow compared to baseline and to VSN-2-infected marrow. No leukemic blast cell colonies were grown from HR-1-infected marrows or control marrows, and HR-1 infection did not confer serum independence. These data show successful retroviral infection of normal bone marrow progenitor cells and suggest that expression of mutant H12-ras in such cells results in enhanced proliferation of early myeloid cells at the expense of differentiation.

Septic Encephalopathy

Septic encephalopathy occurs easily in many septic persons. Manifestations are largely similar to those seen in other metabolic brain diseases. It can be detected most sensitivily, but not specifically, with electroencephalography. Diagnosis is based on excluding other causes of encephalopathy, such as a central nervous system infection or exposure to drugs or toxins. The pathogenesis is unknown but is likely diverse. Its severity correlates with mortality. Early recognition of septic encephalopathy is essential becuase early: diagnosis and treatment of sepsis markedly reduces mortality.

Maternal uniparental disomy for human chromosome 14, due to loss of a chromosome 14 from somatic cells with t(13;14) trisomy 14

Uniparental disomy (UPD) for particular chromosomes is increasingly recognized as a cause of abnormal phenotypes in humans. We recently studied a 9-year-old female with a de novo Robertsonian translocation t(13;14), short stature, mild developmental delay, scoliosis, hyperextensible joints, hydrocephalus that resolved spontaneously during the first year of life, and hypercholesterolemia. To determine the parental origin of chromosomes 13 and 14 in the proband, we have studied the genotypes of DNA polymorphic markers due to (GT)n repeats in the patient and her parents' blood DNA. The genotypes of markers D14S43, D14S45, D14S49, and D14S54 indicated maternal UPD for chromosome 14. There was isodisomy for proximal markers and heterodisomy for distal markers, suggesting a recombination event on maternal chromosomes 14. In addition, DNA analysis first revealed--and subsequent cytogenetic analysis confirmed--that there was mosaic trisomy 14 in 5% of blood lymphocytes. There was normal (biparental) inheritance for chromosome 13, and there was no evidence of false paternity in genotypes of 11 highly polymorphic markers on human chromosome 21. Two cases of maternal UPD for chromosome 14 have previously been reported, one with a familial rob t(13;14) and the other with a t(14;14). There are several similarities among these patients, and a "maternal UPD chromosome 14 syndrome" is emerging; however, the contribution of the mosaic trisomy 14 to the phenotype cannot be evaluated. The study of de novo Robertsonian translocations of the type reported here should reveal both the extent of UPD in these events and the contribution of particular chromosomes involved in certain phenotypes.

A circadian distribution to febrile episodes in neutropenic patients

Four-hourly temperature charts relating to 63 febrile neutropenic episodes in 32 patients were assessed for a circadian distribution to the onset of fever (> 37.5 degrees C) using the Edward's test. A highly significant distribution was found with the maximum incidence of febrile events between the hours of 5 p.m. and midnight (acrophase 9.30 p.m.). Patients were 5.53 times more likely to develop fever at 9.30 p.m. that 9.30 a.m.

Pneumothorax and palliative pleural aspiration--an audit of technique

The incidence of pneumothorax following a review of 55 single-sitting bedside pleural aspirations of malignant effusions over an 18-month period in the clinical oncology departments of the Middlesex and Mount Vernon Hospitals was assessed and two groups were compared. Group 1 (29 aspirations in 16 patients) involved a technique using an 8 ch (French) gauge trocar and cannula, a three-way tap and a sealed bag system, resulting in no pneumothoraces. Group 2 (26 aspirations in 18 patients) involved a variety of other techniques with a pneumothorax rate of 19.2% (p = 0.0189 using Fisher's Exact Test). The small trocar/sealed bag system was complication-free, relatively painless, quick to perform, cheap, gave the option of draining to dryness and was easily learnt by the junior doctors who most often perform this procedure at the bedside. This technique is described in detail in the text. A reduction in the risk of pneumothorax minimizes the need for a postaspiration chest radiograph, facilitating aspiration in an outpatient, hospice or domiciliary setting. A domiciliary study is to be planned using the procedural standard described.

Severe bleomycin lung toxicity: reversal with high dose corticosteroids

A 42 year old man, treated for testicular carcinoma with combination chemotherapy that included bleomycin, developed life threatening interstitial pneumonitis. He recovered successfully after treatment with very high doses of corticosteroids and azathioprine. This report suggests that bleomycin lung toxicity may be reversible if treated aggressively.

Skin anergy and tuberculosis

In our experience tuberculin skin anergy (negative response to 10 TU Mantoux) occurs in 8% of patients with tuberculosis. In this study we compare 81 patients with skin anergy and proven tuberculosis with a background reactive population of patients with tuberculosis. Patients with skin anergy and tuberculosis were older and had fewer symptoms--less cough, less sputum production, less haemoptysis, less malaise, less chest pain--than patients with skin reactivity. There was no difference with respect to male/female ratio, marital status, smoking habits, coexistent major illness, prescribed medications at diagnosis, nor the proportion of patients with extrapulmonary tuberculosis, previous history of BCG vaccination or past history of tuberculosis. Comparison of chest radiographs showed more advanced, more bilateral and more miliary disease in the anergic patients. Pyrexia and elevated ESR at diagnosis were also more common in this group. Fewer of the anergic group of patients were consistently culture negative after 1 month's treatment compared to the background population. Mortality was higher in the anergic group, but this excess mortality occurred from causes other than tuberculosis. Repeat Mantoux testing was performed in 20 of the 81 anergic patients, after a minimum of 3 months of antituberculous chemotherapy, and 14 had become tuberculin positive, suggesting that tuberculin skin anergy may be a temporary phenomenon.

Academic and environmental effects of small group arrangements in classrooms for students with autism and other developmental disabilities

The use of small group instructional formats with children who have autism and developmental disabilities has received mixed results in the research literature (Reid & Favell, 1984). The purpose of the two studies reported herein was to address this controversy by comparing the performance of students in one-to-one instruction to those transitioned to small groups for a variety of teachers, students, settings, and under different training circumstances. In the first study, 41 students, ranging in age from 5 to 21 years old, from six classrooms, participated; and 25 students from six classrooms participated in the second study. Measures of environmental effects included academic gains via pre- and posttests, on-task and self-stimulatory behavior levels, correct responding, and frequencies of teacher behaviors during both one-to-one and small group formats. Results of both experiments indicated that students were able to successfully transition to small group formats across several curriculum areas including language, math, readiness, and shopping. Further, experienced teachers and administrators were able to train a second group of staff to use the small group procedures effectively. The successful application for this number of students and teachers within natural learning environments is unprecedented and provides important documentation for both the utility and practicality of small group instruction with students who have developmental disabilities.

Radiotherapy employing three fractions on each of twelve consecutive days

In order to achieve the greatest advantage of accelerated hyperfractionated radiotherapy, treatment has been given 3 times each day for 12 consecutive days without a rest period. A total tumour dose of 50.4 Gy was well tolerated in a series of 38 patients with bronchial, head and neck and oesophageal carcinomas. A further 14 patients have now received an elevated dose of 54 Gy, again with satisfactory tolerance. The tumour responses at all these sites have been very promising and further work is proceeding.

The membrane proteins of the methanol-induced peroxisome of Candida boidinii. Initial characterization and generation of monoclonal antibodies

Peroxisomes are massively induced when methylotrophic yeasts are cultured on methanol as the sole carbon and energy source. An analysis of the protein composition of the peroxisomal membrane and the generation of probes against two peroxisomal membrane proteins (PMPs) have been undertaken. Peroxisomes from Candida boidinii were obtained from sucrose gradients as previously described or from a novel one-step purification of the organelle on a Percoll gradient. The protein composition of the membranes from these two preparations was virtually identical. About 10 proteins comprise nearly all of its protein mass. The most prominent proteins have molecular masses of 120, 100, 47, 31-32 (a triplet), and 20 kDa; significant amounts of alcohol oxidase and dihydroxyacetone synthase, the two abundant matrix proteins, also remain associated with the membrane. Glycosylation of the membrane proteins could not be detected. Exposure of the membrane to chaotropes shows that PMPs 100 and 20 are the most easily removable, whereas PMP 47 appears to be the most tightly associated. Mice were injected with peroxisomal membrane, and hybridoma lines were isolated that produced antibody against PMP 20, PMP 47, and dihydroxyacetone synthase. Indirect immunofluorescence with these monoclonal antibodies confirmed that all three proteins are localized to the peroxisomal cluster. Immunoblotting experiments demonstrated that peroxisomal membrane as well as matrix proteins are induced by methanol.

The response of human neutrophils to a chemotactic tripeptide (N-formyl-methionyl-leucyl-phenylalanine) studied by microcinematography

A quantitative microcinematographic technique for the measurement of cellular motion in response to chemical influences is described. The data are analyzed by using a magnetic digitizer connected to a computer, permitting comparison of several characteristics of such motion. When human granulocytes are placed in a gradient of formyl-methionyl-leucyl-phenylalanine (fMLP) (concentration 10(-6)-10(-8) mol/L) against buffer, the motion of the cells is increased in velocity (chemokinesis) and is directed toward the chemoattractant, as measured by the orientation of the vector of motion. This directionality is confirmed by positive values for the McCutcheon index and analysis of directed linear displacement. Concentrations of fMLP below 10(-9) mol/L did not result in chemokinesis or chemotaxis, presumably due to insufficient stimulus. Concentrations of 10(-6) mol/L fMLP and greater resulted in marked stimulation of the cell surface but reduced directionality and velocity of motion compared with cells in a more optimal gradient. Motion of the unstimulated cells tended to be ortholinear , and this was not increased by the presence of a gradient of fMLP. Hence, as previously shown, the Random Walk analysis, which does not give weight to the direction of motion, is not useful in the analysis of the response of these cells to a chemotaxin in this system.

Studies on fractionated hyperthermia in experimental animals systems III. Uneven daily doses

The effect of daily hyperthermia on the murine normal and tumor tissues was investigated. Tumors were early generation isotransplants of a fibrosarcoma (FSa-II) and a mammary carcinoma (MCa) in C3Hf/Sed mice. Hyperthermia was given by immersing animal feet into a water bath at 45.5 degrees C. Tumor response was studied by TG time assay (determination of the time required for half of the treated animals' tumors to reach 1000 mm3 from the treatment day). Average peak foot reaction was also investigated to compare the therapeutic effectiveness of various fractionation regimens. In the first experiment the first dose (D1) of 10 min was followed by 10, 20, or 30 min daily doses. The treatment regimen "D1 of 10 min + daily 30 min" resulted in a significant therapeutic gain. The smaller doses were unable to overcome the repopulation of surviving tumor cells and the increasing magnitude of thermal resistance. To overcome tumor cell repopulation and thermal resistance, a regimen of increasing daily doses was attempted without success. These results indicated that doses following a D1 of 10 min must be as large as 30 min to obtain a therapeutic gain. Any fractionation regimens for MCa tumors, which developed the greatest thermal resistance among our animal tumors tested, failed to result in a therapeutic gain.

Thermal resistance in a spontaneous murine tumour

Resistance to subsequent hyperthermia as a result of prior heating was investigated using a spontaneous murine tumour implanted into the feet of C3H/Sed mice. Tumours were treated by immersing the tumour-bearing foot into a constant-temperature hot water bath set at 45.5 degrees C and were given single and split doses of heat. Response was assessed using a tumour-growth time assay. Three aspects of thermally-induced resistance were particularly considered: the time course of development and decay; the importance of the magnitude of the priming dose and the influence of the size of the tumour at the time of treatment. Substantial resistance was induced in this tumour by short priming doses at 45.5 degrees C, rising rapidly 1-2 days after the first treatment and then starting to decay. There was no significant difference in the kinetics of thermal resistance induced in tumours treated at 4mm and those treated at 8 mm in size, although the large tumours were more sensitive to single doses of heat. Increasing the magnitude of the priming dose of heat resulted in an increase in the magnitude of resistance to the second dose. The results of this study are compared with results of similar studies in this and other laboratories using murine normal tissues and cells in culture. Possible clinical implications are considered.

Integrity of perfused rat liver at different heat loads

Isolated rat livers were perfused for 90 minutes at temperatures from 37 degrees to 43 degrees C. to evaluate the effects of heat alone on bile production, alanine aminotransferase, and asparate aminotransferase release, and light and electron microscopic structure. Bile production reached a plateau after 45 minutes at 43 degrees C. and after 60 minutes at 42 degrees C. At temperatures between 39 degrees and 41 degrees C., bile production was not significantly different from that produced at 37 degrees C. The timing and levels of alanine aminotransferase and aspartate aminotransferase released into the perfusates were similar, with increases after 45 minutes at 43 degrees C., after 60 minutes at 41 degrees and 42 degrees C. and after 75 minutes at 39 degrees and 40 degrees C. At the end of the 90-minute perfusion, light microscopy indicated vacuolization and severe dissociation of hepatocytes at 42 degrees and 43 degrees C., and pronounced centrilobular vacuolization at 41 degrees C. Electron microscopy demonstrated that hepatocytes had sustained extensive damage at 41 degrees to 43 degrees C. Mild focal and probably reversible damage occurred at 39 degrees and 40 degrees C. Since pH and O2 levels were regulated in a nonrecirculating system and perfusion rates were constant, neither acidosis, hypoxia, nor circulatory inadequacy were responsible for the alterations. Therefore, changes were attributed to the direct effects of heat, reflected a continuum from no detectable damage at 37 degrees C. to occasional necrosis of individual cells at 39 degrees to 40 degrees C. and culminated in widespread necrosis at 41 degrees to 43 degrees C. with a 90-minute exposure. These results reflect a time/temperature relationship over a range of temperatures. A hypothesis for the sequence of events in the pathogenesis of heat-induced hepatic injury is described.