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Mycotoxins are considered unavoidable contaminants in foods and feeds because agronomic technology has not yet advanced to the stage at which preharvest infection of susceptible crops by fungi can be eliminated. The aflatoxins have received greater attention than any of the other mycotoxins because of their demonstrated carcinogenic effects in susceptible animals and their acute toxic effects in humans. Since 1965, the U.S. Food and Drug Administration (FDA) has enforced regulatory limits on the concentrations of these toxins in foods and feeds involved in interstate commerce. The FDA routinely monitors the food and feed industries through compliance programs to ensure that the levels of exposure to these toxins are kept as low as practical. This report summarizes data generated from compliance programs on aflatoxins for the fiscal years 1989, 1990, and the first half of 1991. Commodities sampled included peanuts and peanut products, tree nuts, corn and corn products, cottonseed, and milk. Higher than usual levels of contamination were found in corn examined from all areas of the United States in 1989 as a result of the severe drought that affected the 1988 corn crop. The drought in parts of the South and Southeast in 1990 resulted in increased contamination in corn and peanuts from those areas. A review of the surveillance data obtained on deoxynivalenol, zearalenone, ochratoxin A, sterigmatocystin, penicillic acid, and patulin over the years along with available toxicological data for these mycotoxins indicated that no regulatory actions were warranted. The lack of sufficient surveillance data on other mycotoxins that occur in the United States can be attributed in part to the unavailability of reliable analytical methodology.

The field desorption mass spectra of several underivatized cyanogenic glycosides exhibit molecular ions or ions derived from the parent compound by protonation and alkali metal cationization. Abundant fragment ions are present and can be readily related to structure. Significant deviations from established fragmentation pathways are observed due to the nature of the aglycone. The ability to successfully determine the presence of cyanogenic glycosides by field desorption is demonstrated in crude extracts isolated from Vicia sativa, a food-contaminating plant material.

The aim in positron emission tomography is to provide quantitative information about the uptake, localization, and turnover of labeled molecules in the human body. Instruments designed for this purpose are based on the coincidence detection of the emitted annihilation photons. In this paper, we examine those instruments that use a ring of detectors. We investigate such instruments with respect to their sampling properties in the stationary and half-rotation modes. It is shown that, although the half-rotation motion provides an improvement if the data are treated as a set of parallel projections, there is no improvement when divergent projections are assumed by the reconstruction procedure. The effects on reconstruction quality of the radial and the angular sampling in ring collected data are discussed and illustrated.

A thoretical consideration of the factors which influence the accumulation of radiopharmaceutials in bone is presented. The avidity with which 99mTc-Sn-pyrophosphate and 18F fluoride are adsorbed by bone crystals has been measured in vitro and the efficiency with which these radiopharmaceuticals are extracted by normal bone has been measured in vivo. It is postulated that alterations in the capillary permeability in the region of a bone lesion greatly influence the target to background ratio that can be obtained with bone seeking radiopharmaceuticals. Quantitiated gamma camera studies in man are presented in support of this hypothesis.

Positron Emission Tomography (PT) scans of the brain were compared in a sexual sadist and two community controls. The participants heard either an erotic audiotape or a sexually neutral tape while penile circumference was monitored. Results showed reliable penile differences between erotic and neutral stimuli. PT results showed that the right hemisphere of the brain was more activated than the left during both types of stimuli but the pattern of activation was not distinct. The erotic stimuli produced greater activation levels but in the same areas of the brain as neutral stimuli. The deep limbic structures of the brain were not especially activated as expected. The sadist differed from the controls in showing more bilateral activation during both types of stimuli but, here too, the same brain sites were activated. Suggestions for future study are discussed.

• This study examines whether the duration of treatment with antipsychotic drugs influences the regional distribution of cerebral [18F]2-fluoro-2-deoxy-D-glucose utilization as measured by positron emission tomography. Two groups of schizophrenic patients are compared with normal volunteers (n =10). One group (n = 5) consisted of patients treated for one year, and the second (n=12) of patients medicated for four to 14 years (mean ± SD duration, 7.4±3.4 years). The first group was also examined before patients received their first dose ever of antipsychotic medication. One year of medication was not sufficient to alter the schizophrenic profile of cerebral cortical glucose activity but did elevate activity of the corpus striatum. Medication for 7.4 years also did not alter the schizophrenic pattern of frontal hyperactivity and posterior hypoactivity, although deviations from control values appeared less marked than after one year. On the other hand, in patients medicated for 7.4 years, there was perhaps an even greater increase in the activity of the corpus striatum and of the thalamus. Thus, duration of exposure to antipsychotic medication may affect the pattern of cerebral glucose activity; possibly, even longer exposure may contribute to the hypofrontality noted by others, although this can be confounded with the duration of illness as a factor. In considering the biological significance of the observed profile of cortical glucose activity, we introduce the concept of cerebral metabolic tone. We suggest that a disturbance of this tonus may account for some symptoms of schizophrenia and could be consistent with the hypothesis of abnormal developmental changes in the brains of schizophrenics.

3,4-Dihydroxy-5-fluorophenylalanine, fluorodopa, was injected into rats in which unilateral lesions of the nigrostriatal pathway had been made. The rats rotated towards the side with the lesions, thus providing further evidence that fluoro-dopa is an analogue of dopa. [18F]Fluoro-dopa was then injected intravenously into fully conscious baboons. A well-collimated scintillation detector, aligned along the occipitomental axis, recorded the accumulation of 18F in the brain. Control animals accumulated 18F continuously for 100 min. This accumulation represents net transport of [18F]fluoro-dopa from blood to brain, decarboxylation to [18F]fluoro-dopamine, storage, and degradation of [18F]fluoro-dopamine. α-Methyl-dopa, a competitive inhibitor of dopa transport and decarboxylation, prevented the accumulation of 18F; reserpine, known to release stored intracerebral dopamine, discharged 18F; pargyline, a monoamine oxidase inhibitor, and haloperidol, a known augmentor of intracerebral dopamine turnover, increased the rate of accumulation of 18F. These changes in the accumulation of intracerebral 18F, after [18F]fluoro-dopa, were commensurate with the known action of the drugs used to induce them and demonstrate the use of a γ-emitting precursor of a neurotransmitter to monitor simply, atraumatically, and externally the intracerebral metabolism of the transmitter in fully conscious primates. When applied to man, the same technique should be able to provide more conclusive evidence than is presently available for the role of catecholamines in schizophrenia and depression. It should also provide further insight into the natural history of nigrostriatal diseases and the action of drugs used in their treatment.

1. Urinary sodium and hydrogen ion excretion was measured in four normal subjects before and after they had ingested 25 g of glucose. The subjects were studied during a sustained water diuresis after an overnight fast and after a 40 h fast. 2. After glucose had been ingested, urinary sodium excretion was reduced by approximately 40% but there was no change in urine flow. The decrease in sodium excretion was associated with a rise in hydrogen ion excretion. 3. These results suggest that sodium ion is retained in exchange for hydrogen ion in the distal segment of the nephron. 4. It is postulated that the increased renal bicarbonate threshold and the metabolic alkalosis which develop when glucose is given to fasted subjects are a consequence of this exchange.

The analysis of positron tomographic studies of 3,4-dihydroxyphenylethylamine (dopamine) metabolism in which [18F]6-fluoro-l-3,4-dihydroxyphenylalanine (F-dopa) is used as a tracer is confounded by the presence of [18F]6-fluoro-3-O-methyl-l-3,4-dihydroxyphenylalanine (OMFD). This labeled molecule, formed by the action of peripheral cathechol-O-methyltransferase on F-dopa, crosses the blood–brain barrier and contributes to the radioactivity measured by the tomograph. Corrections for this radioactivity in the brain have been proposed. They rely upon the assumption that regional variations in the handling of this molecule by the brain are negligible. Although this assumption is pivotal for the proper quantification of dopamine metabolism using F-dopa, the distribution and kinetics of OMFD have never been studied in humans. We present results in humans that show that there is little selective regional 18F accumulation in the brain, that the distribution volume of OMFD is close to unity, and that a single, reversible compartment is adequate to model the measured time course of radioactivity after an OMFD injection. Analysis of plasma samples for labeled metabolites showed that more than 95% of the radioactivity was associated with OMFD at all times. Our results for OMFD kinetics are in accord with published results obtained in nonhuman primates and for the bidirectional transport of large neutral amino acids across the blood-brain barrier measured using a synthetic amino acid. However, our results also indicate that there are small but significant differences in OMFD kinetics in different parts of the brain that may prevent inferences about the handling of OMFD in one part of the brain from being extended to other parts of the brain.

Clinically and pathologically acute haematogenous osteomyelitis displays the characteristics of a typical inflammatory reaction. Local blood flow is increased, the capillaries are dilated and become leaky. These vascular features favour the development of a positive scintiscan following the introduction of a boneseeking radiopharmaceutical (Van Dyke et al., 1965; Garnett et al., 1975). Clearly, the vascular changes will precede any radiologically detectable alterations in bone structure. Accordingly, skeletal scintigraphy is now recommended as a sensitive test to help in the early diagnosis of osteomyelitis (Duszynski et al., 1975; Gilday et al., 1975; Majd and Frankel, 1976; Treves et al., 1976).The purpose of this report is to draw attention to the fact that proven severe acute osteomyelitis in a major long bone need not be associated at a preradiographic stage with a greater than normal accumulation of bone-seeking radiopharmaceutical either in the bone itself or in the surrounding soft tissue.A previously healthy, 11 -year-old boy developed a “flu”- like illness with malaise, diarrhoea and fever. On the second day of his illness he complained of throbbing pain in his right upper arm. There was no known antecedent trauma. Three days later the arm was hot and swollen, marked tenderness was localized over the proximal humerus, but the shoulder could be moved passively throughout its range.

Experimental pulmonary emboli can be difficult to identify with certainty and to quantitate with accuracy by currently available techniques. A new method is reported based on the incorporation of exactly known amounts of radioactive fibrinogen into blood clot before its embolization into the lungs of dogs. The emboli can then be identified by lung scanning and quantitated by counting the lungs. The new method has been found to correspond much more closely than pulmonary angiography to post-mortem observations.

The results of 450 131I-triiodothyronine (T3)-resin uptake tests in euthyroid, hyper- and hypothyroid patients are described.The effects of variation in the temperature and weight of resin on 131I-T3uptake are demonstrated.Limits of normality have been established for a group of 149 euthyroid patients. The 131I-T3-resin uptake test in euthyroid, hyper- and hypothyroid patients has been compared with the 4 and 48 hr. 131I neck uptake, the protein-bound iodine (p.b.i.) concentration and the basal metabolic rate (b.m.r.) as a test of thyroid status.The results suggest that, as a single test for the estimation of thyroid status, the 131I-T3-resin uptake test is as reliable and more convenient than the more established test procedures.

Alexander, AaronD. (Walter Reed Army Institute of Research, Washington, D.C.), Herbert G. Stoenner, Garnett E. Wood, and Robert J. Byrne. A new pathogenic Leptospira, not readily cultivated. J. Bacteriol. 83:754–760. 1962.—A pathogenic Leptospirawas isolated from water of the Grand River, (S.D.) that differed significantly from other known leptospirae in that it could not be cultivated in conventional leptospiral media. Growth was promoted in Fletcher's medium modified to contain 20% rabbit serum. The isolate, after several serial passages, was lethal for hamsters. It could not be adapted to grow in the chick embryo. Guinea pigs and calves inoculated with the isolate developed febrile and antibody responses but showed no other overt signs of disease. The strain was identified on the basis of cross-agglutination and agglutinin-adsorption tests as a new subserotype of Leptospira naamand was therefore designated as L. naam, subserotype dakotii.

The excretion of steroid hormone metabolites was studied in normal, thyrotoxic and myxoedematous subjects. Corticosteroid excretion was increased in thyrotoxicosis and reduced in myxoedema.In myxoedema there was also a fall of total androgen excretion due principally to a reduction of the androsterone component.There was no change in total androgen excretion in thyrotoxic subjects, but there was a fall of aetiocholanolone excretion.

Thyroid hormone binding capacity in serum was measured indirectly by a [131I]tri-iodothyronine (T3) resin uptake method in 36 patients with trophoblastic tumours.A low [131I]T3resin uptake (raised thyroid hormone-binding capacity) was found in approximately one-third of the patients but none showed clinical or other evidence of hypothyroidism. There was no correlation between [131I]T3resin uptake test and gonadotrophin excretion. The results suggest that the increased thyroid-hormone binding capacity found in some patients with trophoblastic tumours may be related to oestrogen secretion and further study is required to establish this.

All forms of trophoblastic tumours may metastasise to the lungs. Three principal forms of metastases are encountered. The first is a discrete form with well-defined rounded opacities; a second presents a “snowstorm” pattern of multiple small soft shadows, and in a third the tumour is confined to the pulmonary arteries so that the clinical and radiological picture closely mimics pulmonary thrombo-embolism. The chemotherapeutic methods used and the results obtained are presented in brief.

Presents letters to the editor on various topics with reference to several articles published in the previous issues. Formation of public opinion on status of India in America; Statement that majority of correspondents in India are British; Comments on the article "Thanks to a Pig," published in the August 20 issue; Comments on the attack upon the Federal Water Power Act; Information on the Power Commission to issue minor licenses for power sites on the New River; "When Population Ceases to Grow," published in the September 3 issue; Criticism of a book by James Joyce; Information on prejudice of British photographer Cecil Beaton against the audifilm "Pitchers."

Presents several letters to the editor, referencing articles and topics published in previous issues. Role of the organization League for Independent Political Action, in bringing about a conservative-progressive alignment in politics; Article written by H. N. Brailsford, on the inevitability of the policy of repression upon which the British Labor Government has embarked in India, published in the May 14 issue; Criticism of actions of British Labor Government in India to satisfy their economic interests; Proposal of the U.S. Congress to reform the calendar.

More than 50 countries have enacted or proposed regulations for the control of aflatoxins in foods and/or feeds, and at least 15 of these countries also have regulations for permitted levels of contamination by other mycotoxins. Since 1965, the U.S. Food and Drug Administration has used action levels to control aflatoxins in its compliance programs. Cooperative programs with the U.S. Department of Agriculture, state agencies, and industry also have been used to keep exposure to aflatoxins as low as practical. Soybeans support the growth of many mold species, which can produce toxins such as aflatoxins, trichothecenes (such as T-2), and cytochalasins. The natural occurrence of these toxins in soybeans has not been a problem. Limited surveys of soybeans and soy-based infant formulas have not revealed significant contamination. The sequence of events that leads to consideration of a mycotoxin for control programs and other regulatory activity includes determination of a toxic response, isolation and identification of the toxin, development of a sampling plan and method of analysis, and determination of incidence and levels of contamination of the susceptible commodity. The quality of soybeans can vary widely, depending on environmental, agronomic, and storage conditions. products susceptible to contamination from improper storage are subject to regulatory action on a case-by-case basis. The government-industry cooperative programs have been successful in limiting human exposure to aflatoxins.

A method of measuring bone blood flow has been developed using 18F sodium fluoride and positron emission tomography. The blood flow levels are in line with those obtained experimentally from microsphere embolisation. This investigative method could be applied to elucidate a number of clinical questions involving bone perfusion.

IntroductionIn Britain, STI diagnoses rates are highest among black Caribbeans compared to other ethnic groups. The prevalence of concurrency is also high in this population. Concurrent partnerships, (i.e. having sexual partners overlapping in time), can enhance the rate and speed of STI transmission. We explored typologies and drivers of concurrency in black Caribbeans in England and considered their implications for STI prevention.MethodsUsing purposive sampling, we recruited people of black Caribbean ethnicity aged ≥15 years from community settings and STI clinics. Audio-recorded 4 focus group discussions (n=28 participants) and 24 in-depth interviews were conducted between June 2014-Dec 2015 using topic guides. Data was transcribed, managed using NVivo software and analysed using thematic framework to identify patterns of concurrent partnerships and condom use, and reasons for concurrency.Results32 women and 20 men (age range: 15–70 years) identifying as heterosexual participated. Open, situational, and experimental concurrent partnerships were commonly reported. Open concurrent partnerships involved a person having a main sexual partner and, in the case of men, additionally having sex with other “side chicks”or “thots”,and in the case of women, “side dicks”. Situational partnerships involved having a sexual relationship with an ex-partner, especially with someone with whom they had had a child, while having another main sexual partner. These types of partnerships were usually long-term, and condoms were less likely to be used due to emotional attachment, if a co-parent was single and then condomless sex was perceived as a way to “entice”the partner back, or due to the relationship being founded on sexual pleasure. Usuallypeople were aware of the concurrent nature of these partnerships. Experimental concurrent partnerships, commonly reported by single participants, were usually short term, and mostly involved condom use. These were fuelled by lack of readiness to settle with a single partner, or trying to figure out the type of partner they may want to settle with. Other commonly reported reasons for concurrency were low self-esteem at an individual level. At a socio-cultural level, although concurrency was frowned upon, it was perceived as “a Black Caribbean thing”with references being commonly made in certain types of popular music and dance among black Caribbeans, changing norms of relationships in an era where you can “order sex via app”, peer pressure, and a normalisation of concurrency on social media, especially among men.ConclusionAmong black Caribbeans, the different types and contexts of concurrent partnerships can have implications for STI prevention. Awareness of being in a concurrent partnership could potentially facilitate uptake of interventions including condom use, partner notification, and reduce the risk of re-infection. In addition, such interventions should address broader sociocultural factors influencing risk behaviour including the impact of media.

TO THE EDITOR.— Berman et al,1 in the July 1988 issue of the Archives, demonstrated increased cerebral blood flow in posterior cortical regions of both schizophrenic subjects and control subjects while they were performing the Raven's Progressive Matrices task. Cerebral blood flow in the two groups did not differ significantly. In contrast, schizophrenics' failure to activate the dorsolateral prefrontal cortex while doing the Wisconsin Card Sort Test2 has now been replicated.3These authors argued that the data support their contention that there is both brain-regional and behavioral specificity in schizophrenia. We suggest that a specific region within the parietal cortex is also related to neurocognitive deficit in schizophrenia.We have recently examined the relationship of scores from a neuropsychological test battery with regional brain fludeoxyglucose F 18 measured by positron emission tomography. The procedures were administered within 1 week of each other. We examined 16 drug-free patients

[18F]-5-fluoro-Dopa is a substrate for dopa decarboxylase of kidney and brain. Its potential use in brain studies is proposed.

The neurotransmitter dopamine has biological attributes that make it amenable to study by positron emission tomography, unlike many of the 40 or so neurotransmitters that have been identified in the brain. Dopamine deficiency in the nigrostriatal system is a characteristic of Parkinson's disease1, and a disturbance of dopamine metabolism is still widely held to be responsible for the syndrome of schizophrenia2. Despite its importance in the regulation of locomotion and mood, it has been impossible to visualize the intracerebral distribution of dopamine and measure its regional metabolism in man. In the first demonstration of the regional distribution of a neurotransmitter in the brain of conscious normal man, we show here that L-3,4-dihydroxyphenylalanine (L-dopa) labelled in the 6-position with the positron-emitting radionuclide fluorine-18, localizes specifically in the dopaminergic pathways of the human brain where its turnover could be measured atraumatically by positron emission tomography.

Gelatin is made by boiling skin, ligament, tendon and bone with water, skimming and filtering the resulting solution and evaporating it to dryness (British Pharmaceutical Codex, 1968). In spite of its crude origin and preparation gelatin has been recommended as a stabilising agent in the preparation of 113Inm-containing radiopharmaceuticals for blood pool, lung and liver scanning to prevent the precipitation of indium hydroxide at pH values of 4 and above (Stern, Goodwin, Scheffel, Wagner and Kramer, 1967; Stern, Goodwin, Wagner and Kramer, 1966; Goodwin, Stern, Wagner and Kramer, 1966).

Changes in hemoglobin concentration in premature infants are difficult to interpret because of variations in blood volume and blood loss. We have determined circulating red cell volume (RCV) and erythrocyte survival by Cr51red cell labelling using capillary techniques. In six infants whose weights varied from 680-1, 320 g, RCV was 29.5 ± 6.4 ml/kg.In these babies, blood lost for laboratory tests during the first three weeks of life averaged 0.81 ml/kg/day. In addition all materials contaminated by blood (sponges, syringes, etc.) were collected and the content of Cr51labelled cells was determined. A correlation was found (r=0.60; p<0.01) between the amount of blood taken for tests and that in contaminated materials (0.08 ml/kg/day).The assessment of erythrocyte survival and of changes in hemoglobin concentration demands quantitation of blood lost through sampling. This, together with direct measurement of RCV permits a more complete evaluation of anemia in small premature infants.

Fluorination of L‐tyrosine (I) results in the formation of 3‐fluoro‐L‐tyrosine (II), while fluorination of the diacetylated ester (III) yields a mixture of (II) and 2‐fluoro‐L‐tyrosine (IV) after hydrolysis.