A case-control study of oral cancer in Beijing, People's Republic of China. Associations with nutrient intakes, foods and food groups

A case-control study of oral cancer was conducted in Beijing, People's Republic of China to examine the association between dietary nutrient intake and risk of oral cancer, both in terms of estimated intake of nutrients and micro-nutrients, and in terms of specific foods and food groups. The study was hospital-based and controls were hospital in-patients matched for age and sex with the cases. The response rate for cases and controls was 100% and 404 case/control pairs were interviewed. The results suggest that increased protein and fat intake are related to a decreased risk of oral cancer. Carbohydrate intake, however, showed a moderate increased risk for oral cancer. Total carotene intake and carotene intake from fruits and vegetables are inversely associated with risk of oral cancer. A similar pattern was observed for dietary vitamin C intake. Dietary fibre derived from fruits and vegetables showed a strong negative association with oral cancer risk, but fibre derived from other sources did not exhibit any protective effect. At the level of foods and food groups, increased consumption of fresh meat, chicken and liver was significantly associated with a reduction in oral cancer risk: the tests for trend were all statistically significant at the P < 0.01 level. Consumption of common carp, hairtail, shrimp and lobster were also associated with decreased risk. Risk was found to increase with increasing consumption of millet and corn bread (P < 0.01) but to decrease with increasing consumption of rice (P < 0.01). Increased consumption of grapes, bananas, oranges, tangerines, peaches and pears were associated with reduced risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Association of serum albumin with blood pressure in the normative aging study

Little is known regarding serum albumin's epidemiologic relation to chronic disease. The relation of serum albumin to blood pressure was assessed in a longitudinal study of men who have been seen at 3- to 5-year intervals since the early 1960s. The authors analyzed data from over 20 years of observation using cross-sectional multiple regression models of blood pressure that allow for the correlation between repeated measures on the same individual (GLMIC models), longitudinal GLMIC models that incorporate terms for the interaction of time with serum albumin at baseline, and models of the slope of individuals' blood pressure over time. Serum albumin levels were found to have a consistently strong relation with both systolic blood pressure and diastolic blood pressure in the cross-sectional GLMIC models only. This relation did not change appreciably when covariates for age, body mass index, alcohol ingestion, smoking, serum calcium, hematocrit, heart rate, and antihypertensive medications were added. A rise in serum albumin of 1 g/dl was associated with 1.79-mmHg and 0.91-mmHg increases in systolic blood pressure and diastolic blood pressure, respectively. This phenomenon may be related to experimental studies linking tryptophan, the only amino acid to bind noncovalently to serum albumin, to a blood pressure-lowering effect mediated by promotion of 5-hydroxytryptamine synthesis in the brain.

Simultaneous measurements of the intra- and extra-cellular oxygen concentration in viable cells

An EPR method that can measure the intra- and extra-cellular oxygen concentration [O2] simultaneously in vitro has been developed using specially designed nitroxides. In the presence of Fe(CN)6(3-) in the medium, intracellular [O2] is measured by a neutral 15N-nitroxide and extracellular [O2] is measured by a negatively charged 14N-nitroxide, since charged species do not enter cells and the EPR spectrum of a 15N-nitroxide does not overlap with that of a 14N-nitroxide. The method is based in part on the minimal broadening of negatively charged nitroxides by Fe(CN)6(3-) and the very effective broadening of neutral nitroxides by the same paramagnetic ions. Results with this method confirm the existence of gradients in [O2] between the extracellular and intracellular compartments in CHO cells and M5076 tumor cells, even without stimulation of cellular respiration by CCCP. The nature of the barrier that needs to be involved to account for the experimental results raises some significant questions.

Delayed-type hypersensitivity responses regulate collagen deposition in the lung

A previous report showed that hamsters immunized by epicutaneous application of 2,4,6-trinitrochloro-1-benzene (TNCB) were susceptible to the development of pulmonary interstitial fibrosis (PIF) if challenged in the lung with the water-soluble form of this hapten 2,4,6-trinitrobenzene sulphonic acid (TNBS). In this study, we investigated the immunological mechanisms that contributed to increased collagen content in the lungs of hapten-immune hamsters after receiving a pulmonary challenge of the sensitizing hapten trinitrophenol (TNP). In order to evaluate the concept that delayed-type hypersensitivity (DTH) reaction modulated their response to TNP in the lung such that it eventuated into PIF, we compared the cutaneous DTH response (48 hr after challenge) with lung collagen deposition (14 days after challenge) in several lines (strains) of hamsters. The inbred LSH strain, was a high responder in the DTH assay to TNP and developed non-resolving PIF in the hapten-immune animals. This is called hapten-immune pulmonary interstitial fibrosis or HIPIF. We also observed that female LSH hamsters were more susceptible to HIPIF induced by TNP than males. On the other hand, age factors influenced DTH and PIF in random-bred LVG hamsters since young hamsters (3 months old) were low responders to TNP and did not develop PIF in the HIPIF model but matured LVG hamsters (retired breeders) possessed DTH reactivity to TNP and subsequently developed PIF. These results suggest that lung collagen deposition in hapten-immune hamster is regulated by T-lymphocyte-mediated immune inflammation (DTH) in the lung and both are dependent on the ability to develop a cutaneous DTH reaction to the hapten. The elucidation of possible mechanisms of DTH-mediated non-granulomatous, non-resolving PIF is important for understanding of the role of environmental chemicals similar in action to haptens in the mediation of skin and lung diseases.

Immunological tolerance to hapten prevents subsequent induction of hapten-immune pulmonary interstitial fibrosis (HIPIF)

Pulmonary interstitial fibrosis (PIF) is a morphological term which in part can be defined as accumulation of collagen in the extracellular matrix. Previously we showed that hamsters sensitized with 2,4,6-trinitro-1-chlorobenzene (TNCB) developed PIF 14 days after an intratracheal challenge with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The participation of delayed-type hypersensitivity (DTH) in lung collagen deposition was clearly demonstrated. In this paper, we use an adaptation of this model to mice and show that the lung collagen deposition observed was related to the genetic ability of the strain to maintain a DTH response to the immunizing hapten (TNP). Specifically, the lung collagen deposition on Day 14 in hapten-sensitized, challenged animals in high responder to TNP (BALB/c, H-2d) was higher than that in low responder mouse (C57BL/6, H-2b). Furthermore, aged C57BL/6 strain (retired breeders) possessed a DTH response to TNP and produced significantly higher accumulation of hydroxyproline than that of TNBS-challenged-only animals. A DTH mechanism for the induction of the fibrosis is consistent with the observation that responder mice that were made tolerant to the antigen were unable to respond to the lung challenge with a specific increase in lung index or collagen deposition. These results suggest that effector T lymphocytes that are important in DTH play a key role in the regulation of lung collagen deposition in hapten-immune pulmonary interstitial fibrosis (HIPIF) in mice.

Ethanol and oleate inhibition of alpha-ketoisovalerate and 3-hydroxyisobutyrate metabolism by isolated hepatocytes

Ethanol inhibited glucose synthesis from alpha-ketoisovalerate by isolated rat hepatocytes without significant inhibition of flux through the branched-chain alpha-ketoacid dehydrogenase complex. Accumulation of 3-hydroxyisobutyrate, an intermediate in the catabolism of alpha-ketoisovalerate, was increased by ethanol, indicating inhibition of flux at the level of 3-hydroxyisobutyrate dehydrogenase. 3-Hydroxybutyrate caused the same effects as ethanol, suggesting inhibition was a consequence of an increase in the mitochondrial NADH/NAD+ ratio. Flux through the 3-hydroxyisobutyrate dehydrogenase was more sensitive to regulation by the mitochondrial NADH/NAD+ ratio than flux through the branched-chain alpha-ketoacid dehydrogenase. Oleate also inhibited glucose synthesis from alpha-ketoisovalerate, but marked inhibition of flux through the branched-chain alpha-ketoacid dehydrogenase complex was caused by this substrate.

Extracorporeal shock wave lithotripsy and methyl tert-butyl ether for gallbladder stones

Twenty-one patients with gallbladder stones of 1.1-2.6 cm in diameter were treated by extracorporeal shock wave lithotripsy (ESWL) combined with dissolution using methyl tert-butyl ether (MTBE). In 18 of 21 patients, ESWLs were followed by MTBE instillation through a catheter placed percutaneously via the liver and the gallbladder bed under ultrasonographic and fluoroscopic guidance. As a result, 15 of the 18 patients were cleared of their stones after 54 minutes to 3 hours of dissolution. In the other three cases initially treated by MTBE, ESWLs were added because of no dissolution or poor efficacy. Consequently, after additional 3-5 hours of instillation, complete dissolution in one and subtotal dissolution in two were achieved. Our preliminary results indicated that ESWL followed by MTBE dissolution in the management of cholesterol gallbladder stones was reasonable. On the one hand, ESWL can enhance dissolution by increasing the surface area of stone, and on the other hand MTBE can instantly clear the fragments created by ESWL, so that long-term bile acid intake and potential side effects caused by fragment migration might be avoided.

Antitumor agents. 124. New 4 beta-substituted aniline derivatives of 6,7-O,O-demethylene-4'-O-demethylpodophyllotoxin and related compounds as potent inhibitors of human DNA topoisomerase II

A series of 6,7-O,O-demethylene-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (18-23), 6,7-O,O-demethylene-6,7-O,O-dimethyl-4'-O-demethyl-4 beta-(substituted anilino)-4-desoxypodophyllotoxins (28-31), and their corresponding 4'-O-methyl analogues (12-17 and 24-27) have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. Compounds 18-23 are 2-fold more potent than etoposide and compounds 12, 16, 17, 30, and 31 are as active as etoposide in their inhibition of the human DNA topoisomerase II. Compounds 19 and 20 and 29-31 are as active or more active than etoposide in causing protein-linked DNA breakage. These results indicate that a free C-4' hydroxy group is essential for the DNA breakage activity, and that the hydroxyl groups at C-6 and -7 positions may be involved in an interaction which is responsible for the inhibitory activity of DNA topoisomerase II. The maintenance of an intact methylene dioxy-type ring-A system would contribute to enhanced activity. In addition, the sterically less hindered substitution at C-6 and C-7 positions may be important for optimal interactions with DNA topoisomerase II. There is no correlation between the ability of these compounds to inhibit DNA topoisomerase II and their ability to cause protein-linked DNA breaks in cells. This may relate to the difference in uptake of these compounds. The better correlation was observed between the protein-linked DNA breaks and the cytotoxicity in KB cells of these compounds.

Antitumor agents. 123. Synthesis and human DNA topoisomerase II inhibitory activity of 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins

The 2'-chloro derivatives of etoposide and 4 beta-(arylamino)-4'-O-demethylpodophyllotoxins have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The results showed that none of the compounds are active as a result of the C-2' chloro substitution on ring E. This would suggest that the free rotation of ring E is essential for the aforementioned enzyme inhibitory activity. In addition, these 2'-chloro derivatives showed no significant cytotoxicity (KB).

[Anti-inflammatory effect of radix Angelicae sinensis]

Radix Angelicae Sinensis (RAS) decoction can markedly inhibit acute and chronic inflammation caused by various phlogistic agents. Similar effects are equally seen in adrenalectomized rats. RAS can also suppress the biosynthesis or release of prostaglandin E2 in inflamed tissues induced by carrageenan, as well as significantly decrease the hemolytic activity of complement bypass, but shows no effect on the inflammation caused by histamine.

EPR method for the measurement of cellular sulfhydryl groups

An EPR method that can measure the concentration of sulfhydryl groups in intact cells has been developed using a specially designed stable nitroxyl biradical. The biradical, RS-SR, contains a disulfide bond and readily undergoes thiol-disulfide exchange reactions with thiols resulting in a characteristic EPR spectrum which can be analyzed to provide a quantitative measure of sulfhydryl groups. The data obtained from the EPR method are in good agreement with those obtained from the conventional optical method using Ellman's reagent. The advantages of the EPR method are that the measurement can be carried out on intact cells or any other highly colored, absorbing and/or scattering solutions and the sensitivity is such that only a few cells (approximately 100) are needed for each quantitative measurement.

The use of K X-ray fluorescence for measuring lead burden in epidemiological studies: high and low lead burdens and measurement uncertainty

X-ray fluorescence (XRF), a rapid, noninvasive, low-radiation-dose method of measuring bone lead content, has emerged as a promising tool for providing an integrated estimate of low-level lead accumulation in epidemiological studies. Our group has settled on an XRF instrument that utilizes K X-rays (K-XRF) and normalizes the measurement to bone calcium. The unit of measurement provided is in micrograms of lead/gram bone mineral, an accurate proxy for micrograms of lead/gram bone ash. An estimate of measurement uncertainty is generated from the counting statistics and is theoretically dependent on several factors, primarily duration of measurement and bone mass. Data from pilot studies of community-exposed adults and workers with varying degrees of occupational lead exposure demonstrated that the K-XRF instrument can easily distinguish between populations with occupational versus environmental lead exposures. Among all subjects, bone lead increased with age. Larger measurement uncertainty was significantly associated with being female, greater subject weight, and smaller lead burdens.

Knowledge of diagnosis and reproductive history among survivors of childhood plumbism

As part of a study of the long-term consequences of childhood plumbism, 35 survivors of lead poisoning in the period 1930 through 1944 were interviewed along with 22 controls matched for age, sex, and town of residence. Subjects were asked to recall all pregnancies they engendered (men) or carried (women), outcome, and intellectual development of resulting children. Matched female plumbism subjects reported a higher proportion of spontaneous abortion or stillbirths among pregnancies (relative risk = 1.60, 95% confidence interval [CI] = 0.6-4.0) and a higher proportion of learning disabilities among school-age children (relative risk = 3.0, 95% CI = 0.9-10.2) in comparison with their controls. There was no evidence of clustering of learning disabilities within families or confounding by parental educational level. These results suggest that women with a history of childhood lead poisoning may be at risk for having spontaneous abortions or stillbirths and having children who manifest significant learning disabilities.

Measurements of pertinent concentrations of oxygen in vivo

A new method able to measure the concentration of oxygen in complex biological systems, including in vivo, has been developed using low-frequency EPR and newly characterized free radicals that are very sensitive to the concentration of oxygen. The free radicals (fusinite and lithium phthalocyanine) are very stable in tissues (for at least 150 days), apparently nontoxic, and can reflect oxygen concentrations that are less than the Km of cytochrome oxidase (0.1 microM or lower). Their biological stability is indicated by the fact that repeated measurements with fusinite of the concentration of oxygen in skeletal muscle have been made in the same animal for more than 150 days without any change in sensitivity or signs of toxicity.

The use of K X-ray fluorescence for measuring lead burden in epidemiological studies: high and low lead burdens and measurement uncertainty

X-ray fluorescence (XRF), a rapid, noninvasive, low-radiation-dose method of measuring bone lead content, has emerged as a promising tool for providing an integrated estimate of low-level lead accumulation in epidemiological studies. Our group has settled on an XRF instrument that utilizes K X-rays (K-XRF) and normalizes the measurement to bone calcium. The unit of measurement provided is in micrograms of lead/gram bone mineral, an accurate proxy for micrograms of lead/gram bone ash. An estimate of measurement uncertainty is generated from the counting statistics and is theoretically dependent on several factors, primarily duration of measurement and bone mass. Data from pilot studies of community-exposed adults and workers with varying degrees of occupational lead exposure demonstrated that the K-XRF instrument can easily distinguish between populations with occupational versus environmental lead exposures. Among all subjects, bone lead increased with age. Larger measurement uncertainty was significantly associated with being female, greater subject weight, and smaller lead burdens.

[Studies on the mutagenicity of vesnarinone]

The mutagenicity of domestic Vesnarinone (OPC-8212) was studied by Ames test, micronucleus test of NIH mouse bone marrow and chromosome aberration assay in CHL cells. Negative results were obtained, which suggested that OPC-8212 did not induce prokaryotic cell gene mutation or chromosome damage both in vitro and in vivo.

A 50-year follow-up of childhood plumbism. Hypertension, renal function, and hemoglobin levels among survivors

A group of 192 subjects with well-documented lead poisoning in 1930 to 1942 were identified in this pilot study. Thirty-five of 72 survivors traced to a Boston area address and 22 age-, sex-, race-, and neighborhood-matched controls were recruited into a clinical study. One matched subject with plumbism had grossly abnormal renal function and an elevated blood lead level of an unclear cause. Among the remaining 21 matched pairs, the risk of hypertension was significantly higher in subjects with plumbism (relative risk, 7.0; 95% confidence interval, 1.2 to 42.3). Mean adjusted creatinine clearance rates for subjects with plumbism, however, were significantly higher than those of controls and supranormal in comparison to rates predicted for sex and age. Subjects with plumbism had significantly lower hemoglobin concentrations and hematocrit readings than the controls. Blood lead and serum creatinine levels were low for both groups. These results suggest that survivors of childhood lead poisoning have an increased risk of clinically significant hypertension developing in the setting of supranormal creatinine clearance rates.

The cytological and genetic characterisation of doubled haploid lines derived from triticale×wheat hybrids

Anther culture, when applied to hexaploid triticale×wheat hybrids, offers the opportunity to re-assort wheat D genome and rye R genome chromosomes into homozygous doubled haploid lines in a single generation. The characterisation of such lines is the first step in their utilisation in wheat improvement. Two lines, M24 and M25 from the cross of 'Beagle'×'Kedong 58', and one line, M27, from the cross 'Beagle'×'Jinghua No. 1' have been characterised using different methods including conventional cytology and chromosome banding, and by using marker systems for storage protein composition (glutenins and gliadins), isozymes (α-amylase, aminopeptidase, glutamate oxaloacetic transaminase (GOT)) and RFLP markers. The results from all approaches were consistent in proving that M24 is a whole chromosome 6R/6D substitution line, while M25 and M27 are whole chromosome 1R/1D substitution lines. The relative advantages and disadvantages of each method of identification are also discussed.

Effect of repeated occupational exposure to lead, cessation of exposure, and chelation on levels of lead in bone

A sensitive K-X-ray fluorescence (K-XRF) instrument was used to measure lead levels in the tibia and patella on a series of twelve subjects who had relatively well-documented histories of lead exposure and blood lead levels. For some subjects, K-XRF measurements were taken at multiple points in time, and before and after chelation with EDTA (ethylenediamine tetraacetic acid). Results confirm that K-XRF measured bone lead levels correspond to cumulative blood lead indices and not to current blood lead levels. Moreover, the data suggest that bone lead levels; (1) correspond to urinary lead following the EDTA mobilization test unless previous chelation has occurred; (2) rise initially after lead exposure ceases and blood lead levels decrease, probably from redistribution from soft tissue, and then fall; and (3) do not decrease with a 3- to 5-day course of therapeutic EDTA chelation. K-XRF levels in the patella were noted to decrease more rapidly than levels in the tibia after cessation of lead exposure, a finding that probably reflects the greater turnover of lead in trabecular bone than in cortical bone.

[A new serotype of Salmonella IIIb]

An enterobacterium culture, S3188, providing with Salmonella biological characteristics, except exhibiting indole positive reaction, was isolated from the intestinal content of reptile a snake. It utilized malonate, did not ferment dulcitol, it attacked lactose promptly, and ONPG positive. H antigens appeared diphasic. By cross agglutination and absorption tests, it was demonstrated that the antigenic formula of this strain is 53:1, Z13:e, n,(Z15)... It was found to be a new serotype of Salmonella IIIb.

X-ray fluorescence measurements of lead burden in subjects with low-level community lead exposure

A k-x-ray fluorescence (K-XRF) instrument that can measure in vivo bone lead at low levels was used on a population of 34 adults with no known history of excessive lead exposure. A questionnaire that gathered information relevant to occupational and environmental lead exposure was administered prior to the measurement. A 30-min measurement that produced an average estimated uncertainty of 6 mcg lead/g bone mineral was taken at the mid-tibial diaphysis for each subject. Eighteen subjects had bone lead levels below the measurement uncertainty. The remainder had bone lead levels ranging up to 21 mcg lead/g bone mineral. Bone lead levels were greater among older subjects. Among young adult subjects, bone lead levels greater than the measurement uncertainty were confined entirely to subjects who had grown up in housing that was estimated to have been build prior to 1955. Such a childhood environment is at high risk of fostering exposure to biologically absorbable lead through ingestion of lead paint-contaminated dust and lead pipe-contaminated water. We conclude that the K-XRF technique has the potential to distinguish between low levels of lead burden in epidemiologic studies.

Hemoglobin Birmingham and hemoglobin Galicia: two unstable beta chain variants characterized by small deletions and insertions

Two unstable hemoglobins (Hbs) causing rather severe hemolytic anemia have been characterized. The beta chain of Hb Birmingham, found in an adult black man, is characterized by the loss of -Leu-Ala-His-Lys- at positions 141, 142, 143, and 144 and their replacement by one Gln residue. These changes are the result of a deletion of nine nucleotides, namely two base pairs (bp) of codon 141, all of codons 142 and 143, and one bp of codon 144; the remaining CAG triplet (C from codon 141 and AG from codon 144) codes for the inserted glutamine. In the beta chain of Hb Galicia from a Spanish patient, His and Val at positions 97 and 98 are replaced by one Leu residue. This is due to an ACG deletion in codons 97 and 98, which causes the removal of one His and one Val residue, while the remaining CTG triplet (C from codon 97 and TG from codon 98) codes for the inserted leucine residue. Two mechanisms, namely slipped mispairing in the presence of short repeats, and misreading by DNA polymerase due to a local distortion of the DNA helix, are considered in explaining the origin of the small deletions.

Molecular characterization of beta-thalassaemia in 174 Greek patients with thalassaemia major

The mutations producing beta-thalassaemia in 174 Greek patients with thalassaemia major were investigated by dot-blot hybridization of oligonucleotide probes to genomic DNA amplified by the polymerase chain reaction procedure, by direct sequencing of amplified DNA, and by gene mapping. beta-thalassaemia in Greeks was found to be very heterogeneous at the molecular level as 17 different mutations were observed: 86.6% of the beta-thalassaemic genes, however, could be identified with five probes: IVS-I-110 (G----A) (42.5%), codon 39 (C----T) (17%), IVS-I-1 (G----A) (13.2%), IVS-I-6 (T----C) (7.2%) and IVS-II-745 (C----G) (6.9%). Several mutations which had not previously been reported in the Greek population and which occurred at an incidence of 2% or lower were observed in this study. The information obtained will facilitate the prenatal diagnosis of beta-thalassaemia in Greece.

Effects of ultraviolet radiation

Ultraviolet radiation from high-intensity sources has well-known acute effects on the eye and skin, consisting primarily of photokeratoconjunctivitis and sunburn, which are enhanced in the presence of photosensitizing agents. Long-term elevated exposure to low-level ultraviolet radiation is also responsible for an increased risk of squamous- and basal-cell carcinomas; probably responsible for an increased risk of cortical and posterior subcapsular cataracts, pterygium, and cutaneous melanoma and intraocular melanoma and possibly responsible for immunologic effects of clinical significance.

Tear gas--harassing agent or toxic chemical weapon?

Tear gas has gained widespread acceptance as a means of controlling civilian crowds and subduing barricaded criminals. The most widely used forms of tear gas have been o-chlorobenzylidenemalononitrile and omega-chloroacetophenone. Proponents of their use claim that, if used correctly, the noxious effects of exposure are transient and of no long-term consequences. The use of tear gas in recent situations of civil unrest, however, demonstrates that exposure to the weapon is difficult to control and indiscriminate, and the weapon is often not used correctly. Severe traumatic injury from exploding tear gas bombs as well as lethal toxic injury have been documented. Moreover, available toxicological data are deficient as to the potential of tear gas agents to cause long-term pulmonary, carcinogenic, and reproductive effects. Published and recent unpublished in vitro tests have shown o-chlorobenzylidenemalononitrile to be both clastogenic and mutagenic. Sadly, the nature of its use renders analytic epidemiologic investigation of exposed persons difficult. In 1969, eighty countries voted to include tear gas agents among chemical weapons banned under the Geneva Protocol. There is an ongoing need for investigation into the full toxicological potential of tear gas chemicals and renewed debate on whether their use can be condoned under any circumstances.

The use of chemical weapons. Conducting an investigation using survey epidemiology

The use of chemical weapons in conflict represents a breach of international law as well as a grave violation of human rights. Investigating allegations of their use often is difficult. A basic tool is the survey interview. Experience has shown that a rigorous epidemiologic approach should be taken. A primary emphasis should be designing the study so that consistency of responses can be analyzed to judge the validity of the testimony. Only when the testimony can withstand this scrutiny is it possible to surmise the possible identity of agents employed. Securing samples of the putative agent is of obvious importance. Two recent investigations are discussed herein, one conducted by US Army medical researchers on allegations of chemical weapons use against the Hmong in Laos and another mounted by us on allegations of poison-gas attack against the Iraqi Kurds.

Recombination of R-D chromosome in pollen plants cultured from hybrid of 6x Triticale x common wheat

Ninety-three pollen plants derived from the hybrid F1 of 6x Triticale x common wheat were observed cytologically. The rye chromosomes presented in these plants were identified by Giemsa-banding. Pollen plants having chromosome constitution 2n = 24 in haploids and 2n=46 in diploids were found to be predominant. The chromosome distributions of the R and D genome are different. R chromosomes distributed randomly and tended to full combination in offspring, but D chromosomes distributed non-randomly and tended to maintain intact.

Quantitation of hemoglobins Bart's, H, Portland-I, Portland-II and constant spring by anion-exchange high-performance liquid chromatography

We introduce a new high-performance liquid chromatographic procedure that uses a specific anion-exchange column for the separation of hemoglobin (Hb) Bart's (gamma 4), Hb H (beta 4), Hb Portland-I (zeta 2 gamma 2), Hb Portland-II (zeta 2 beta 2), and the abnormal Hb Constant Spring (alpha 2 extended beta 2) in cord blood and adult red cell lysates. The method provides quantitative data for Hb Bart's in cord blood that correlate well with the alpha-globin gene status of the babies and can be used for an initial identification of alpha-thalassemic conditions. Quantitation of Hb Bart's from cord blood samples that are collected on filter paper and submitted as dried blood spots is unreliable. The separation of Hb H and Hb Bart's allows an evaluation of the synthesis of these two hemoglobin components in patients with Hb H disease.

Beta-thalassemia intermedia in two Turkish families is caused by the interaction of Hb Knossos [beta 27(B9)Ala----Ser] and of Hb City of Hope [beta 69(E13)Gly----ser] with beta (0)-thalassemia

We have studied a few members of two Turkish families, who had a beta-thalassemia of the intermediate type. An abnormal hemoglobin was found in both families, which when present in association with beta(0)-thalassemia was considered to be the primary cause for the increased severity of the disease. In the first family this variant was Hb Knossos [beta 27(B9)Ala----Ser] which occurred together with the frameshift in codon #8 type of beta(0)-thalassemia. This compound heterozygosity, observed for the first time in the Turkish population was characterized by a considerable increase in Hb F production, mainly of the G gamma type, as expected for a chromosome with haplotype IV. In the second family, the variant was Hb City of Hope [beta 69(E13)Gly----Ser] which was present in combination with an unknown type of beta-thalassemia. The increase in Hb F production in the compound heterozygote was minimal. Reversed phase high performance liquid chromatography and the DNA amplification-synthetic oligonucleotide probe procedure were major tools in identifying the different abnormalities.