Cannabinoids function in defense against chewing herbivores in Cannabis sativa L

In the decades since the first cannabinoids were identified by scientists, research has focused almost exclusively on the function and capacity of cannabinoids as medicines and intoxicants for humans and other vertebrates. Very little is known about the adaptive value of cannabinoid production, though several hypotheses have been proposed including protection from ultraviolet radiation, pathogens, and herbivores. To test the prediction that genotypes with greater concentrations of cannabinoids will have reduced herbivory, a segregating F2 population of Cannabis sativa was leveraged to conduct lab- and field-based bioassays investigating the function of cannabinoids in mediating interactions with chewing herbivores. In the field, foliar cannabinoid concentration was inversely correlated with chewing herbivore damage. On detached leaves, Trichoplusia ni larvae consumed less leaf area and grew less when feeding on leaves with greater concentrations of cannabinoids. Scanning electron and light microscopy were used to characterize variation in glandular trichome morphology. Cannabinoid-free genotypes had trichomes that appeared collapsed. To isolate cannabinoids from confounding factors, artificial insect diet was amended with cannabinoids in a range of physiologically relevant concentrations. Larvae grew less and had lower rates of survival as cannabinoid concentration increased. These results support the hypothesis that cannabinoids function in defense against chewing herbivores.

Correlations among morphological and biochemical traits in high-cannabidiol hemp (Cannabis sativa L.)

Cannabis sativa is cultivated for multiple uses including the production of cannabinoids. In developing improved production systems for high-cannabinoid cultivars, scientists and cultivators must consider the optimization of complex and interacting sets of morphological, phenological, and biochemical traits, which have historically been shaped by natural and anthropogenic selection. Determining factors that modulate cannabinoid variation within and among genotypes is fundamental to developing efficient production systems and understanding the ecological significance of cannabinoids. Thirty-two high-cannabinoid hemp cultivars were characterized for traits including flowering date and shoot-tip cannabinoid concentration. Additionally, a set of plant architecture traits, as well as wet, dry, and stripped inflorescence biomass were measured at harvest. One plant per plot was partitioned post-harvest to quantify intra-plant variation in inflorescence biomass production and cannabinoid concentration. Some cultivars showed intra-plant variation in cannabinoid concentration, while many had a consistent concentration regardless of canopy position. There was both intra- and inter-cultivar variation in architecture that correlated with intra-plant distribution of inflorescence biomass, and concentration of cannabinoids sampled from various positions within a plant. These relationships among morphological and biochemical traits will inform future decisions by cultivators, regulators, and plant breeders.

First Report of Downy Mildew caused by Pseudoperonospora cannabina on Cannabis sativa in New York

Hemp (Cannabis sativa <0.3% tetrahydrocannabinol) is an emerging crop used for grain, fiber, and cannabinoid production (Fike et al. 2020). In New York, hemp is grown both in controlled environment facilities, including greenhouses, and as a field crop. In August 2020, downy mildew-like symptoms were observed on leaves and inflorescence of hemp plants in a field research trial in Ithaca, NY. Several cultivars, including 'Auto CBD', were affected. Disease was severe with some plants reaching 75% disease severity at the individual plant level. In the most severely affected plots, there was no marketable yield. The disease was characterized by chlorotic and necrotic lesions producing sporangiophores under high humidity. Pigmented sporangia were produced on branched sporangiophores. On artificially inoculated leaves incubated at 18°C, 80% humidity, 12h light for 5d, sporangiophores produced 8-19 pigmented, lemon-shaped sporangia with mean ± SD dimensions of 25.2 ± 3.0 (18.9 to 30.4) x 18.2 ± 2.1 (14.6 to 23.2) µm (n=50). Each sporangium produced 2-5 zoospores after less than 45 min in water at room temperature (22°C). Sporangia were collected from sporulating lesions and DNA was extracted as outlined in Crowell et al. (2020). Fragments of the ribosomal internal transcribed spacer (ITS) region (White et al. 1990), the beta-tubulin ras-associated ypt1 gene (Moorman et al. 2002), and the mitochondrial cytochrome B oxidase subunit 2 (cox2) gene (Hudspeth et al. 2000) were amplified by PCR and sequenced bidirectionally. Sequences were deposited in GenBank under accession numbers OK086084, OM867581, and OM867580, respectively. BLAST searches using the amplified ITS and cox2 sequences resulted in 100% identity to Pseudoperonospora cannabina (HM636051.1, HM636003.1) with ypt1 aligning at 97.95% identity (382/390 bp) with P. cannabina (KJ651402.1). The molecular characterization identified the causal agent as P. cannabina. A representative isolate was deposited in the Cornell Plant Pathology Herbarium as CUP-070922. Sporangia were rinsed from detached leaves and used to confirm pathogenicity on whole plants. Ten 4-week-old 'Anka' plants were spray-inoculated until run off with a suspension of 1x104 sporangia mL-1. Ten control plants were sprayed with water. After inoculation, plants were placed in a 19˚C growth chamber with a 12-h photoperiod and misted for 30 min twice daily to maintain humidity above 80%. Sporangia and previously described symptoms were observed 7 days post-inoculation, while control plants were asymptomatic. The pathogen was reisolated onto detached leaves of 'Anka' from inoculated leaves where both sporangia and oospores were observed. The reisolated pathogen was confirmed morphologically and molecularly, through PCR amplification and bidirectional sequencing of the ITS, cox2, and ypt1 genes, as P. cannabina. To our knowledge, this is the first report of P. cannabina causing hemp downy mildew in New York. Depending on the severity and timing of infections, this disease could pose a significant threat to hemp production in the state. Other members of the genus, P. cubensis and P. humuli cause downy mildew on cucurbits and hops, respectively. As these can cause devastating diseases on their hosts, P. cannabina must be monitored with vigilance as an emerging pathogen (Purayannur et al. 2021; Savory et al. 2011). Literature Cited: Crowell, C. R., et al.2020. Plant Dis. 104:2949. DOI 10.1094/PDIS-04-20-0718-RE Fike, J. H., et al. 2020. Page 89 In: Sustainable Agriculture Reviews, vol 42. Springer, Cham, Switzerland. DOI 10.1007/978-3-030-41384-2_3 Hudspeth, D. S. S., et al. 2000. Mycologia 92:674. DOI 10.2307/3761425 Moorman, G. W., et al. 2002. Plant Dis. 86:1227. DOI 10.1094/PDIS.2002.86.11.1227 Purayannur, S., et al. 2021. Mol. Plant Pathol. 22:755. DOI 10.1111/mpp.13063 Savory, E. A., et al. 2011. Mol. Plant Pathol. 12:217. DOI 10.1111/j.1364-3703.2010.00670.x White, T. J., et al. 1990. Page 315 In: PCR Protocols. A Guide to Methods and Applications. Academic Press, San Diego, CA. DOI 10.1016/B978-0-12-372180-8.50042-1.

Embedded tin nanocrystals in silicon-an electrical characterization

Tin nanocrystals embedded in a SiSn layer grown by molecular beam epitaxy on n-type Si are investigated by means of deep level transient spectroscopy. Two Sn related deep traps are observed, depending on the annealing temperature of the samples. A deep level at [Formula: see text] (Sn1) is observed for annealing temperatures up to [Formula: see text]C, whereas a level at [Formula: see text] (Sn2) appears for annealing temperatures above [Formula: see text]C. Scanning transmission electron microscopy shows the formation of Sn nanocrystals at [Formula: see text]C, which coincides with the appearance of Sn2. Sn1 is tentatively assigned to a Sn related precursor defect, which transforms upon annealing into either Sn nanocrystals or an interface defect located at the nanocrystal surface.

Genomic Prediction of Biomass Yield in Two Selection Cycles of a Tetraploid Alfalfa Breeding Population

Alfalfa (Medicago sativa L.) is a widely planted perennial forage legume grown throughout temperate and dry subtropical regions in the world. Long breeding cycles limit genetic improvement of alfalfa, particularly for complex traits such as biomass yield. Genomic selection (GS), based on predicted breeding values obtained using genome-wide molecular markers, could enhance breeding efficiency in terms of gain per unit time and cost. In this study, we genotyped tetraploid alfalfa plants that had previously been evaluated for yield during two cycles of phenotypic selection using genotyping-by-sequencing (GBS). We then developed prediction equations using yield data from three locations. Approximately 10,000 single nucleotide polymorphism (SNP) markers were used for GS modeling. The genomic prediction accuracy of total biomass yield ranged from 0.34 to 0.51 for the Cycle 0 population and from 0.21 to 0.66 for the Cycle 1 population, depending on the location. The GS model developed using Cycle 0 as the training population in predicting total biomass yield in Cycle 1 resulted in accuracies up to 0.40. Both genotype × environment interaction and the number of harvests and years used to generate yield phenotypes had effects on prediction accuracy across generations and locations, Based on our results, the selection efficiency per unit time for GS is higher than phenotypic selection, although accuracies will likely decline across multiple selection cycles. This study provided evidence that GS can accelerate genetic gain in alfalfa for biomass yield.

Effects of cognitive therapy versus interpersonal psychotherapy in patients with major depressive disorder: a systematic review of randomized clinical trials with meta-analyses and trial sequential analyses

BACKGROUND

Major depressive disorder afflicts an estimated 17% of individuals during their lifetime at tremendous suffering and cost. Cognitive therapy and interpersonal psychotherapy are treatment options, but their effects have only been limitedly compared in systematic reviews.

METHOD

Using Cochrane systematic review methodology we compared the benefits and harm of cognitive therapy versus interpersonal psychotherapy for major depressive disorder. Trials were identified by searching the Cochrane Library's CENTRAL, Medline via PubMed, EMBASE, Psychlit, PsycInfo, and Science Citation Index Expanded until February 2010. Continuous outcome measures were assessed by mean difference and dichotomous outcomes by odds ratio. We conducted trial sequential analysis to control for random errors.

RESULTS

We included seven trials randomizing 741 participants. All trials had high risk of bias. Meta-analysis of the four trials reporting data at cessation of treatment on the Hamilton Rating Scale for Depression showed no significant difference between the two interventions [mean difference -1.02, 95% confidence interval (CI) -2.35 to 0.32]. Meta-analysis of the five trials reporting data at cessation of treatment on the Beck Depression Inventory showed comparable results (mean difference -1.29, 95% CI -2.73 to 0.14). Trial sequential analysis indicated that more data are needed to definitively settle the question of a differential effect. None of the included trial reported on adverse events.

CONCLUSIONS

Randomized trials with low risk of bias and low risk of random errors are needed, although the effects of cognitive therapy and interpersonal psychotherapy do not seem to differ significantly regarding depressive symptoms. Future trials should report on adverse events.

beta-Arrestin 1 and 2 stabilize the angiotensin II type I receptor in distinct high-affinity conformations

BACKGROUND AND PURPOSE

The angiotensin II type 1 (AT(1)) receptor belongs to family A of 7 transmembrane (7TM) receptors. The receptor has important roles in the cardiovascular system and is commonly used as a drug target in cardiovascular diseases. Interaction of 7TM receptors with G proteins or beta-arrestins often induces higher binding affinity for agonists. Here, we examined interactions between AT(1A) receptors and beta-arrestins to look for differences between the AT(1A) receptor interaction with beta-arrestin1 and beta-arrestin2.

EXPERIMENTAL APPROACH

Ligand-induced interaction between AT(1A) receptors and beta-arrestins was measured by Bioluminescence Resonance Energy Transfer 2. AT(1A)-beta-arrestin1 and AT(1A)-beta-arrestin2 fusion proteins were cloned and tested for differences using immunocytochemistry, inositol phosphate hydrolysis and competition radioligand binding.

KEY RESULTS

Bioluminescence Resonance Energy Transfer 2 analysis showed that beta-arrestin1 and 2 were recruited to AT(1A) receptors with similar ligand potencies and efficacies. The AT(1A)-beta-arrestin fusion proteins showed attenuated G protein signalling and increased agonist binding affinity, while antagonist affinity was unchanged. Importantly, larger agonist affinity shifts were observed for AT(1A)-beta-arrestin2 than for AT(1A)-beta-arrestin1.

CONCLUSION AND IMPLICATIONS

beta-Arrestin1 and 2 are recruited to AT(1A) receptors with similar ligand pharmacology and stabilize AT(1A) receptors in distinct high-affinity conformations. However, beta-arrestin2 induces a receptor conformation with a higher agonist-binding affinity than beta-arrestin1. Thus, this study demonstrates that beta-arrestins interact with AT(1A) receptors in different ways and suggest that AT(1) receptor biased agonists with the ability to recruit either of the beta-arrestins selectively, would be possible to design.

Functional variation in the arginine vasopressin 2 receptor as a modifier of human plasma von Willebrand factor levels

SUMMARY OBJECTIVES

Stimulation of arginine vasopressin 2 receptor (V2R) with arginine vasopressin (AVP) results in a rise in von Willebrand factor (VWF) and factor VIII plasma levels. We hypothesized that gain-of-function variations in the V2R gene (AVPR2) would lead to higher plasma levels of VWF and FVIII.

METHODS AND RESULTS

We genotyped the control populations of two population-based studies for four AVPR2 variations: a-245c, G12E, L309L, and S331S. Rare alleles of a-245c, G12E, and S331S, which were in linkage disequilibrium, were associated with higher VWF propeptide, VWF and FVIII levels. The functionality of the G12E variant was studied in stably transfected MDCKII cells, expressing constructs of either 12G-V2R or 12E-V2R. Both V2R variants were fully glycosylated and expressed on the basolateral membrane. The binding affinity of V2R for AVP was increased three-fold in 12E-V2R-green fluorescent protein (GFP) cells, which is in accordance with increased levels of VWF propeptide associated with the 12E variant. The dissociation constant (K(D)) was 4.5 nm [95% confidence interval (CI) 3.6-5.4] for 12E-V2R-GFP and 16.5 nm (95% CI 10.1-22.9) for 12G-V2R-GFP. AVP-induced cAMP generation was enhanced in 12E-V2R-GFP cells.

CONCLUSIONS

The 12E-V2R variant has increased binding affinity for AVP, resulting in increased signal transduction, and is associated with increased levels of VWF propeptide, VWF, and FVIII.

Complete activation of Bax by a single site mutation

Bax translocation from the cytosol to mitochondria culminates a key step by which this protein mediates cell death. Here, we identified two amino acids, L70 and D71, within the BH3 domain of Bax that play a critical role in regulating Bax's cytosolic vs mitochondrial distribution. Individual substitution of these amino acids with alanine resulted in Bax conformational change, oligomerization, localization to mitochondria and cell death. Further mutational analysis indicated that L70 interacts with T174, V177 and A178 of Bax's C-terminal hydrophobic segment, while the negative charge of D71 is required for maintaining Bax in its soluble monomeric state. In summary, we have identified a new regulatory site that controls Bax's subcellular distribution and activation.

Localization of cap-binding protein in subcellular fractions of HeLa cells

The 26,000-M(r) cap-binding protein was analyzed by a cross-linking assay in cell fractions from uninfected and poliovirus-infected HeLa cells. Cap-binding protein was found in the postribosomal supernatant (S-200) and in the ribosomal salt wash. The cap-binding protein in the S-200 had a sedimentation coefficient of 5 to 7S and lacked the ability to restore translation in extracts of poliovirus-infected cells.

Stability balloon for two-dimensional vortex ripple patterns

Patterns of vortex ripples form when a sand bed is subjected to an oscillatory fluid flow. Here we describe experiments on the response of regular vortex ripple patterns to sudden changes of the driving amplitude a or frequency f. A sufficient decrease of f leads to a "freezing" of the pattern, while a sufficient increase of f leads to a supercritical secondary "pearling" instability. Sufficient changes in the amplitude a lead to subcritical secondary "doubling" and "bulging" instabilities. Our findings are summarized in a "stability balloon" for vortex ripple pattern formation.

[Visits to hospital emergency departments after restricted-admission changes at the Rigshospitalet]

INTRODUCTION

The aim of this study was to describe changes in the use of accident and emergency departments in the Copenhagen Hospital Co-operation after restricted admittance to the accident and emergency department at a large Danish university hospital, Rigshospitalet (admittance only for patients transported by ambulance or presenting with a referral from a doctor).

MATERIAL AND METHODS

A retrospective study compared the number of patients treated in two periods, 1.7.1998 to 30.6.1999 and 1.7.1999 to 30.6.2000. Additional patient data were collected for the periods 1.7.1998 to 31.12.1998 and 1.7.1999 to 31.12.1999.

RESULTS

A 4% decrease was seen in the total number of patients treated at the accident and emergency departments. The decrease in the number of patients treated at the accident and emergency department at Rigshospitalet was 69%, whereas the accident and emergency department at Bispebjerg Hospital experienced a 53% rise.

DISCUSSION

The study showed good compliance in the local population after the restricted admittance to an accident and emergency department at a large university hospital. An expected total fall in the number of patients treated at the accident and emergency departments in the Copenhagen Hospital Co-operation could not be documented.

Structure and low-temperature thermal relaxation of ion-implanted germanium

The structure of implantation-induced damage in Ge has been investigated using high resolution extended X-ray absorption fine structure spectroscopy (EXAFS). EXAFS data analysis was performed with the Cumulant Method. For the crystalline-to-amorphous transformation, a progressive increase in bond-length was observed without the presence of an asymmetry in interatomic distance distribution (RDF). Beyond the amorphization threshold the RDF was dose dependent and asymmetric, where the bond-length and asymmetry increased as functions of ion dose. Such an effect was attributed to the formation of three- and five-fold coordinated atoms within the amorphous phase. Low-temperature thermal annealing resulted in structural relaxation of the amorphous phase as evidenced by a reduction in the centroid, asymmetry and width of the RDF, as consistent with a reduction in the fraction of non four-fold coordinated atoms. The results have been compared to other EXAFS studies of amorphous Ge, and it is suggested that the range of bond-lengths reported therein is related to the sample preparation method and state of relaxation.

Functional reconstitution of the angiotensin II type 2 receptor and G(i) activation

On the basis of the patterns of conserved amino acid sequence, the angiotensin II type 2 (AT(2)) receptor belongs to the family of serpentine receptors, which relay signals from extracellular stimuli to heterotrimeric G proteins. However, the AT(2) receptor signal transduction mechanisms are poorly understood. We have measured AT(2)-triggered activation of purified heterotrimeric proteins in urea-extracted membranes from cultured COS-7 cells expressing the recombinant receptor. This procedure removes contaminating GTP-binding proteins without inactivating the serpentine receptor. Binding studies using [(125)I] angiotensin (Ang) II revealed a single binding site with a K(d)=0.45 and a capacity of 627 fmol/mg protein in the extracted membranes. The AT(2) receptor caused a rapid activation of alpha(i) and alpha(o) but not of alpha(q) and alpha(s), as measured by radioactive guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) binding. Activation required the presence of activated receptors, betagamma, and alpha subunits. As a first step aimed at developing an in vitro assay to examine AT(2) receptor pharmacology, we tested a battery of Ang II-related ligands for their ability to promote AT(1) or AT(2) receptor-catalyzed G(i) activation. Two proteolytic fragments of Ang II, Ang III and Ang1-7, also promoted activation of alpha(i) through the AT(2) receptor. Furthermore, we found that [Sar(1),Ala(8)]Ang II is an antagonist for both AT(1) and AT(2) receptors and that CPG42112 behaves as a partial agonist for the AT(2) receptor. In combination with previous observations, these results show that the AT(2) receptor is fully capable of activating G(i) and provides a new tool for exploring AT(2) receptor pharmacology and interactions with G-protein trimers.

Implications of physical symmetries in adaptive image classifiers

It is demonstrated that rotational invariance and reflection symmetry of image classifiers lead to a reduction in the number of free parameters in the classifier. When used in adaptive detectors, e.g. neural networks, this may be used to decrease the number of training samples necessary to learn a given classification task, or to improve generalization of the neural network. Notably, the symmetrization of the detector does not compromise the ability to distinguish objects that break the symmetry.

Structure of the RNA-dependent RNA polymerase of poliovirus

BACKGROUND

The central player in the replication of RNA viruses is the viral RNA-dependent RNA polymerase. The 53 kDa poliovirus polymerase, together with other viral and possibly host proteins, carries out viral RNA replication in the host cell cytoplasm. RNA-dependent RNA polymerases comprise a distinct category of polymerases that have limited sequence similarity to reverse transcriptases (RNA-dependent DNA polymerases) and perhaps also to DNA-dependent polymerases. Previously reported structures of RNA-dependent DNA polymerases, DNA-dependent DNA polymerases and a DNA-dependent RNA polymerase show that structural and evolutionary relationships exist between the different polymerase categories.

RESULTS

We have determined the structure of the RNA-dependent RNA polymerase of poliovirus at 2.6 A resolution by X-ray crystallography. It has the same overall shape as other polymerases, commonly described by analogy to a right hand. The structures of the 'fingers' and 'thumb' subdomains of poliovirus polymerase differ from those of other polymerases, but the palm subdomain contains a core structure very similar to that of other polymerases. This conserved core structure is composed of four of the amino acid sequence motifs described for RNA-dependent polymerases. Structure-based alignments of these motifs has enabled us to modify and extend previous sequence and structural alignments so as to relate sequence conservation to function. Extensive regions of polymerase-polymerase interactions observed in the crystals suggest an unusual higher order structure that we believe is important for polymerase function.

CONCLUSIONS

As a first example of a structure of an RNA-dependent RNA polymerase, the poliovirus polymerase structure provides for a better understanding of polymerase structure, function and evolution. In addition, it has yielded insights into an unusual higher order structure that may be critical for poliovirus polymerase function.

Regulation of the onset of meiosis in the developing testis

Meiotic division begins the process of spermatogenic maturation leading to sperm formation. In contrast to the ovary, in which meiosis is initiated early in development, onset of meiosis in the testis is delayed until the time of puberty. An assay procedure was utilized to evaluate factors responsible for the activation and prevention of meiosis in the developing rabbit testis. Testicular specimens from postnatal rabbits at different ages were used to determine if meiosis-activating substance (MAS) activity and meiosis-preventing substance (MPS) activity could be demonstrated prior to the onset of spermatogenesis. An in vitro system in which undifferentiated gonads from 11.5 day old mouse fetuses are cultured in test and control media was employed. The findings indicate that MAS activity is associated with the onset of spermatogenesis and is also present shortly after birth. Activity of MPS is present throughout much of the prespermatogenic period, with a decline to reach low levels at the onset of spermatogenesis.

Design of an ultrasonic therapy system for breast cancer treatment

This paper describes the design of a novel ultrasonic therapy system dedicated to the breast cancer treatment and the theoretical investigation of the heating characteristics of the system. The applicator is a cylinder comprised of a stack of rings. Each ring has up to 48 transducers mounted on the inside of the ring and directed towards the centre. The transducers operate in one of two frequency bands (1.8-2.8 MHz and 4.3-40.8 MHz), arranged alternately in each ring. During treatment the patient is positioned in prone position, with the breast immersed in water and surrounded by this array. This design was modelled and optimized by 3-D simulations for a variety of treatment conditions. The simulated results demonstrate that the system has an excellent capability to achieve and maintain a temperature distribution (41.5-44 degrees C) in a quadrant to a whole breast. Initial experiments using a single ring of transducers has been performed to verify the power deposition calculation.

Pilot study of local hyperthermia, radiation therapy, etanidazole, and cisplatin for advanced superficial tumours

Five patients (six hyperthermia sites) with advanced superficial tumours were treated with combined etanidazole, cisplatin, local hyperthermia, and radiation therapy as part of a Phase I pilot study. Treatment was given once weekly and consisted of etanidazole 3 gm/m2 IV bolus, cisplatin 50 mg/m2 IV bolus, hyperthermia for 60 min with a target temperature of 43 degrees C, and radiation therapy 500 cGy/fraction (median total dose 3000 cGy) for a total of six weeks. Blood levels of etanidazole were taken during treatment at week 1 and week 4. Etanidazole drug exposure was calculated using the trapezoidal rule and expressed as the area under the curve (AUC) of plasma concentration x time. Five of six treatment sites had received prior irradiation. Prior chemotherapy had been given in three patients and tamoxifen therapy given in the other two patients. The median follow-up time is 34 months; 3/5 patients have died of disease. The most significant toxicity was grade I or II nausea and vomiting associated with 19/32 treatments (59%) and a second degree burn in 2/6 fields. None of the five patients experienced peripheral neuropathy, skin ulceration, or needed surgical repair. In addition, there was mild renal toxicity; pharmacokinetic analysis showed a 28-75% increase in the week 1 to week 4 AUC in three patients, all of whom had a decrease in creatinine clearance over the same time of 15-47%. This pilot study suggests this combined modality therapy can be delivered without major complications and that renal function, determined by creatinine clearance, affects clearance of etanidazole and alters the AUC. Therefore, monitoring renal function is important in patients receiving etanidazole in addition to other nephrotoxic agents such as cisplatin. The impact of etanidazole on the therapeutic index of hyperthermia, radiation therapy and cisplatin may be worth of study, especially since a positive interaction between these modalities is found in laboratory models.

Local hyperthermia, radiation therapy, and chemotherapy in patients with local-regional recurrence of breast carcinoma

We retrospectively reviewed the response rate and the acute and long-term toxicity of combined treatment using radiation therapy, hyperthermia, and chemotherapy in 29 patients with locally or regionally recurrent or advanced adenocarcinoma of the breast who completed at least 4 of the 6 prescribed hyperthermia treatments as part of a Phase I-II trial. Thirty-nine separate hyperthermia treatment fields were evaluated. Cisplatin alone or cisplatin with etanidazole or bleomycin was delivered just prior to hyperthermia once weekly. Hyperthermia was delivered to a target minimum tumor temperature of 43 degrees C +/- 0.5 for 60 min. Following hyperthermia, a 400 cGy fraction of radiation was given. The radiation fraction size on other days was 200 cGy. Twenty-two fields had previously been irradiated and 17 fields had not. Prior chemotherapy had been given in 24 of 29 patients (83%) and hormonal therapy given in 21 (72%). The median follow-up time is 10 months; 16/29 patients (55%) have died of disease. The overall complete response rate for all fields was 53%. Response rate was not related to any clinical factor, radiation dose, microwave or ultrasound technique, type of chemotherapy, or tumor temperatures, but the number of patients in the study population was small. A statistically significant association between the likelihood of complications and the total radiation therapy dose (previous radiation and present radiation) was found. Persistent ulceration lasting greater than 1 month after completing treatment was seen in 67% of previously irradiated fields compared to 21% of fields that had not been previously treated (p = 0.015). Surgical wound repair was needed for 38% of fields with a history of prior irradiation versus 6% of those without prior treatment (p = 0.050). A statistically significant radiation therapy dose response was found for the likelihood of these complications. None of the hyperthermia temperature parameters studied correlated with an increased risk of complication. We conclude that the combination of radiation therapy, hyperthermia, and chemotherapy results in a high rate of complete response. However, in patients who have been treated with prior radiation therapy, this combination may be more locally toxic than treatment with hyperthermia and radiation therapy alone. The precise impact of chemotherapy on the therapeutic index of hyperthermia and radiation therapy remains to be determined in randomized clinical trials.

Rescue angioplasty during myocardial infarction has a beneficial effect on mortality: a tenable hypothesis

HYPOTHESIS

Rescue percutaneous transluminal coronary angioplasty (PTCA) reduces mortality during myocardial infarction.

OBJECTIVE

To determine if PTCA after failed thrombolytic therapy results in reduced mortality.

DESIGN

Twenty-eight patients with a persistently occluded infarct artery following thrombolytic therapy more than 3 h after symptom onset were randomized to rescue PTCA (n = 16) or conservative treatment (n = 12) as part of a prospective randomized trial of reperfusion therapy during myocardial infarction in 184 patients. Hospital mortality was assessed in these groups as well as in the 177 patients with known infarct artery status after initial attempts at reperfusion.

MAIN RESULTS

There was one death among the 16 patients in the rescue PTCA group versus four deaths in the 12 patients treated conservatively (P = 0.13). Moreover, the death in the rescue PTCA group occurred in one of three patients in whom the procedure failed. Mortality in the entire study group was 10.3% (19 of 184); 4.2% (six of 142) in patients in whom patency was achieved after thrombolysis and/or PTCA and 34.3% (12 of 35) in those in whom reperfusion was not achieved (P less than 0.001). In patients with anterior myocardial infarction, mortality was 6.7% (four of 60) in those with reperfusion and 47.1% (eight of 17) in those with a persistently occluded artery (P less than 0.001). In patients with inferior myocardial infarction, 2.4% (two of 82) with reperfusion and 22.2% (four of 18) with a persistently occluded artery died (P less than 0.01).

CONCLUSIONS

Although the number of patients in the randomized groups was small, the trend toward a lower mortality after rescue PTCA supports the hypothesis that rescue PTCA may be beneficial. The mortality results in relation to presence or absence of reperfusion from the entire study population underscores the importance of achieving patency during myocardial infarction.

Relation between flow grade after thrombolytic therapy and the effect of angioplasty on left ventricular function: a prospective randomized trial

Recent intervention trials during myocardial infarction demonstrated no benefit from emergency angioplasty after thrombolytic therapy when compared with either delayed percutaneous transluminal coronary angioplasty (PTCA) or a conservative strategy. However, it is possible that subgroups of patients may benefit from early intervention with angioplasty. We performed a prospective randomized trial in patients with a patent infarct-related artery after thrombolytic therapy to determine whether initial flow grade is related to infarct-zone function and whether patients with ineffective reperfusion (greater than 90% stenosis or Thrombolysis in Myocardial Infarction [TIMI] flow less than or equal to 2) might benefit from immediate PTCA. Thrombolytic therapy was administered to 170 patients at a mean of 2.1 +/- 0.5 hours after onset of myocardial infarction. A patent infarct-related artery that was suitable for angioplasty was present in 89 patients who comprised the study group; after randomization, 47 of 50 patients with a patent infarct-related artery had successful emergency PTCA 3.8 +/- 1.5 hours after onset of symptoms, and 39 were scheduled for delayed (18 to 48-hour) PTCA. Reocclusion occurred before the scheduled (delayed) procedure in eight patients (20.5%), and was symptomatic in six. Infarct-region function (by the centerline method) measured initially, before discharge, and at 4 months was similar in both groups; improvement was significant (p less than 0.001) at discharge when compared with initial values with no further change at 4 months. However, patients with ineffective reperfusion had greater hypokinesia initially (p less than 0.05) compared with those with effective reperfusion (less than or equal to 90% stenosis plus TIMI flow 3). Moreover, independent of the timing of PTCA, improvement was greater before discharge in patients with ineffective reperfusion (p less than 0.05) with a trend also evident at 4 months. Importantly, 42 of 51 patients (82%) with a residual lumen less than 0.4 mm after thrombolysis had some improvement in function at discharge; this compared with a previous study in which patients with a similar degree of stenosis (without PTCA) had no improvement. Moreover, reocclusion occurred before scheduled (delayed) PTCA in 37% of patients with greater than 90% stenosis compared with only 5% in those with less than or equal to 90% stenosis (p = 0.02). Thus flow grade is an important determinant of myocardial function in patients with a patent artery after thrombolytic therapy and is predictive both of improvement in wall motion after PTCA and early reocclusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Neonatal hemochromatosis. Genetic analysis of transferrin-receptor, H-apoferritin, and L-apoferritin loci and of the human leukocyte antigen class I region

Neonatal hemochromatosis (NH), a generally fatal disorder of infancy, is characterized by severe hepatic insufficiency of intrauterine onset and by marked organ iron loading. Its cause is unknown. It has been suggested that NH may represent an unusual manifestation of hereditary hemochromatosis (HH), which is human leukocyte antigen (HLA) linked. Evidence for major rearrangements or deletions at the HLA class I region and at three loci directly involved in iron metabolism (H- and L-apoferritin and the transferrin receptor [TfR]) was sought. The population studied included five probands with NH and 14 first-degree family members in a total of six kindreds. Also sought were HLA associations with NH by collating the results of HLA serotyping in these 19 persons and in 17 members of 7 additional kindreds in which NH has occurred, including 5 probands with NH and 12 first-degree family members. We found no evidence for major rearrangements or deletions in H- or L-apoferritin genes, in TfR genes, or within the HLA locus. We found no evidence for linkage of NH to HLA serotypes. We conclude that while NH and HH are similar in their patterns of iron loading, they are not genetically related.

Effect of short-term prostacyclin administration on restenosis after percutaneous transluminal coronary angioplasty

The effect of short-term prostacyclin (PGI2) administration on the incidence of restenosis after coronary angioplasty was studied in a prospective single-blind randomized trial of 286 patients. Of the 270 patients in whom dilation was successful, 134 received prostacyclin and 136 received placebo. Intracoronary prostacyclin was administered before and after dilation and then intravenously for 48 h. The control group received intracoronary placebo infusions before and after dilation. All patients received aspirin and dipyridamole before and after angioplasty, at least until follow-up angiography. Follow-up angiograms were obtained in 93% of patients in whom angioplasty was successful. Restenosis of one or more lesions was present in 34 patients (27%) who were given prostacyclin compared with 40 patients (32%) in the control group (p = NS). Acute vessel closure and ventricular tachyarrhythmias were more common in the control group than in the patients who received prostacyclin (acute vessel closure occurred in 14 [10.3%] of 136 versus 4 [3.0%] of 134, respectively, p less than 0.01; ventricular tachyarrhythmias occurred in 5 [3.4%] of 147 versus 0 of 139 respectively, p less than 0.05). Short-term administration of prostacyclin did not significantly lower the risk of restenosis after coronary angioplasty.

A point mutation in the coding region of uroporphyrinogen decarboxylase associated with familial porphyria cutanea tarda

Familial porphyria cutanea tarda (PCT) is inherited as an autosomal dominant trait caused by decreased activity of uroporphyrinogen decarboxylase (URO-D). In most families with PCT, URO-D mRNA levels are normal but both catalytic activity and immunologic reactivity of URO-D are half normal. We have cloned and sequenced 8 URO-D cDNA transcripts derived from a pedigree member with familial PCT. Three of the cDNAs had sequences encoding normal URO-D but five cDNA's contained a point mutation resulting in a gly----val substitution at amino acid position 281. An oligonucleotide probe complementary to the mutant sequence hybridized to DNA from affected individuals within the pedigree, but not to DNA from normal individuals. Measurements of pulse labeled URO-D in Epstein-Barr virus transformed lymphocytes indicated that the mutant protein has a half-life in vivo of less than four hours. In vitro measurements utilizing labeled URO-Ds generated in a reticulocyte lysate system revealed a 12-hour half-life for the mutant protein compared with a 102-hour half-life for normal URO-D. This is the first URO-D mutation to be characterized in a pedigree with familial PCT. This mutation was not detected in affected individuals from seven other PCT pedigrees, suggesting that PCT can result from different mutations.

The HLA class I locus: analysis of RFLPs in hereditary hemochromatosis

The gene for hereditary hemochromatosis is linked to the HLA locus on chromosome 6. Four cloned DNA probes originating from the HLA class I region were used to detect seven restriction fragment length polymorphisms (RFLPs). Allele frequencies and segregation of each RFLP was determined. Analysis of RFLPs in 38 unrelated homozygotes with hemochromatosis revealed differences in allele frequencies between the control and the hemochromatotic groups but these differences did not reach statistical significance. Some differences persisted, however, even when only controls with the A3 antigen were compared with A3 hemochromatotics. Since both control and hemochromatotic groups were small, further studies will be necessary to ascertain whether these RFLPs could serve to locate the gene responsible for hereditary hemochromatosis.

The influence of ionization chamber and phantom design on the measurement of lung dose in photon beams

Lung dose correction factors, commonly defined as the ratios of ionization chamber readings in the heterogeneous and homogeneous phantoms, have been compared with those based on accurately determined doses. An analysis of stopping power values, Pwall values, and measurements in lunglike and waterlike materials showed that the wall material and thickness are not very critical in the determination of lung dose correction factors under conditions of electronic equilibrium. When lateral electronic equilibrium is not established due to the extended range of scattered electrons in the low density material, Prepl differs significantly from unity for ionization chambers with thick walls which do not match the lung material in density. An attempt has been made to characterize this effect as a function of photon energy, lung density, field size, and wall thickness.

Radiosurgery for arteriovenous malformations of the brain using a standard linear accelerator: rationale and technique

We have recently initiated a program for irradiating small, unresectable arteriovenous malformations (AVM's) in the brain. The treatments are delivered using a modified and carefully calibrated 6 MV linac. We are using high, single doses (15 to 25 Gy) with a goal of sclerosing the vessels and preventing hemorrhages. This technique, radiosurgery, is somewhat controversial in the radiotherapy community. Since the treatment is given in a single sitting, rather than in the more conventional pattern of multiple small daily fractions, there is some concern about late radiation damage to the normal brain tissue. However an extensive review of the literature leads us to the conclusion that if a technique is used that keeps the volume irradiated to high dose small, radiosurgery is a safe and efficacious treatment for small (less than 2.5 cm) AVM's. To decrease the risk of necrosis of normal brain tissue, it is important to confine the high dose region as tightly as possible to the target volume. Precise target localization and patient immobilization is achieved using a stereotactic head frame which is used during angiography, CT scanning, and during the radiation treatment. This minimizes the margin of safety that must be added to the target volume for errors in localization and set-up. The treatment is delivered using multiple noncoplanar arcs, with small, sharp edged X ray beams, and with the center of the AVM at isocenter. This produces a rapid dropoff of dose beyond the target volume. Early results in our first few patients are encouraging.

Steady-state levels of uroporphyrinogen decarboxylase mRNA in lymphoblastoid cell lines from patients with familial porphyria cutanea tarda and their relatives

Familial porphyria cutanea tarda (PCT) results from a generalized deficiency of uroporphyrinogen decarboxylase (URO-D) activity. The molecular defect responsible for this disorder has not been characterized. To determine whether decreased levels of URO-D mRNA are responsible for subnormal URO-D activity, steady-state levels of URO-D mRNA in lymphoblastoid cells were determined. Northern blots were hybridized with a URO-D cDNA probe and quantified by densitometry. No difference in the levels of URO-D mRNA was detected between affected individuals and their normal relatives. Thus, the deficiency of URO-D activity in two familial PCT pedigrees characterized here does not arise from a deficiency of URO-D mRNA.

Familial porphyria cutanea tarda: hybridization analysis of the uroporphyrinogen decarboxylase locus

Familial porphyria cutanea tarda (PCT) results from a deficiency of uroporphyrinogen decarboxylase (URO-D) activity. Hybridization analysis of genomic DNA from unrelated normal individuals and PCT pedigree members failed to detect any major deletions, rearrangements or restriction fragment length polymorphisms at the URO-D locus.

Measurements of dose distributions in small beams of 6 MV x-rays

Dose distributions produced by small circular beams of 6 MV x-rays have been measured using ionisation chambers of small active volume. Specific quantities measured include tissue maximum ratios (TMR), total scatter correction factors (St), collimator scatter correction factors (Sc) and off-axis ratios (OAR). Field sizes ranged from 12.5 to 30 mm diameter, and were defined by machined auxiliary collimators with the movable jaws set for a 4 cm x 4 cm field size. Due to the lack of complete lateral electronic equilibrium for these small fields, the accuracy of the measurements was also investigated. This was accomplished by studying dose response as a function of detector size. Uncertainties of 2.5% were observed for the central axis dose in the 12.5 mm field when measuring with an ionisation chamber with a diameter of 3.5 mm. The total scatter correction factor exhibits a strong field size dependence for fields below 20 mm diameter, while the collimator scatter correction factor is constant and is defined by the setting of the movable jaws. Off-axis ratio measurements show larger dose gradients at the beam edges than those achieved with conventional collimator systems. Corrected profiles measured with an ionisation chamber are compared with measurements made with photographic film and LiF thermoluminescent dosemeters.

A new system for patient fixation in radiotherapy

A new system for patient fixation in radiation treatment is described. The system consists of an airtight plastic bag with a contents of polysterol microspheres. A valve allows evacuation which results in a rigid close fitting cast. The system was compared with conventional foam cast fixation in 29 patients who were treated for carcinoma of the breast. The patients received radiation treatment over 22 fractions, and portal X-ray pictures were obtained at every second treatment. The portal films were compared with the stimulator radiographs and the variation in the position of the centre cross were measured in cranio-caudal and transversal direction as well as the rotation of the centre cross. The results showed that the daily reproducibility of the patient set-up was considerably improved by the new system, the centre cross deviation of the position of the actual radiation field to the centre cross of the intended field being less than 1 mm in 50% of the cases. The system is time-saving and cheap compared to conventional fixation systems.

Isolation of a gene segment expressed by mature schizonts of Plasmodium knowlesi

Fragments of Plasmodium knowlesi DNA, generated by mung bean nuclease digestion, were ligated into the lambda gt11 vector. This expression library was immunoscreened with a serum which inhibits invasion of erythrocytes by merozoites in vitro and whose primary specificity is directed against a Mr 140 000 merozoite surface antigen. One of the isolated clones contained a 125 base pair insert which hybridized to a 1.8 kilobase species of schizont RNA, indicating that this insert is part of a gene expressed during schizogony.

A scanning-slit x-ray videoabsorptiometric technique for bone mineral measurement

An x-ray videoabsorptiometric technique was developed for measurement of bone mineral content (BMC) in vivo. The principle utility of this technique is the precise measurement of commonly fractured bones, such as the femoral neck, that are difficult to measure by other techniques because of repositioning problems. Scanning slits reduce scattered radiation and improve linearity of measurements. Heavily filtered, high-kVp beams are used to minimize errors from beam hardening, and data renormalization is employed to compensate for spatial nonuniformities of the beam and detector. Linearity of measured BMC over the range 0.8 to 5 g/cm2 is very good (r = 0.998) and compares well to single- and dual-photon absorptiometry. A 1.6% change in measured BMC is observed for a 10% change (approximately 2 cm) in tissue thickness while a 10% change in marrow type causes a 0.6%-0.8% change in BMC. Manual repositioning of a femur phantom revealed a variation of 0.84% over ten measurements when femur values were referenced to standards. A computer repositioning algorithm provides much easier identification of the region for analysis and yields comparable variation (0.9%).

Mung bean nuclease cleaves Plasmodium genomic DNA at sites before and after genes

Mung bean nuclease was found to cut the genomic DNA of the malaria parasite Plasmodium at positions before and after genes but not within gene-coding regions. This cleavage, which had nearly the preciseness of a restriction nuclease, required controlled conditions in the presence of formamide. Southern blot analysis showed that the coding areas for Plasmodium actin, circumsporozoite protein, histidine-rich protein, ribosomal RNA's, and tubulin are each cleaved from genomic DNA to yield a single major band on an agarose gel. DNA sequence data on several clones of mung bean nuclease cleavage products containing the gene for the circumsporozoite protein of Plasmodium falciparum confirmed that cleavage sites are before and after genes. Recognition and cleavage of DNA did not seem to be related to any primary sequence but may be related to structural features of the DNA duplex that demarcate genes. Mung bean nuclease-cleaved DNA could be inserted directly into a lambda expression vector, yielding a representative but small gene bank of intact gene fragments.

Development of a Danish preventive program for preschoolchildren based on cooperation with key-persons

Plans to expand public child dental services to include preschoolchildren and the recently established training of dental hygienists in Denmark form the background for the present study. The study was performed in a rural municipality located 35 km north of Aarhus. Public child dental services for schoolchildren (6-16 years of age) had been established for several years and were being planned to include preschoolchildren. In cooperation with the personnel in the Child Dental Service a full-time employed dental hygienist developed a communication network with different categories of key-persons (health nurses, private daycare mothers and nursery school teachers). Close records and diaries were kept during the entire 3-year study period. The paper summarises the experience gained from co-operation with a large number of key-persons and illustrates some of the conditions necessary for a successful process. The effect of the program on dental caries is discussed.