A newly characterized HLA-DP beta-chain allele. Evidence for DP beta heterogeneity within the DPw4 specificity

cDNA clones corresponding to the DPw4 alpha- and DPw4 beta-chains were isolated from a cDNA library prepared from a DPw4 homozygous cell line, their nucleotide sequences were determined, and the corresponding amino acid sequences were deduced. This DPw4 alpha-chain is identical to the conserved DP alpha-chains from DPw4 and DPw2 haplotypes, although the DPw4 beta-chain (referred to as DPw4b beta) differs from all reported DP beta-chain sequences. The DPw4b beta-chain differs from the reported DPw4 beta sequence (referred to as DPw4a beta) at three amino acid positions in the first domain (36, 55, and 56). The DPw4b beta-chain sequence differs from the DPw2 beta-chain sequence only at position 69 in the first domain, suggesting that the lysine at position 69 in DPw4b beta and the glutamic acid at position 69 in DPw2 beta contribute to the epitopes that define "DPw4-ness" and "DPw2-ness," respectively. In addition, the patterns of sequence identities and differences among the DPw4b beta-, DPw4a beta-, DPw2 beta-, and DPw3 beta-chains suggest that the DPw4b beta sequence arose via a gene conversion event or a point mutation. The I-LR1 mAb, which was previously found to bind only to DPw2, DPw3, and DR5 molecules, binds to an L cell transfectant expressing the DPw4 alpha:DPw4b beta molecule. The DPw4b beta sequence provides the first evidence for structural heterogeneity within the DPw4 specificity.

Antibodies to lactate dehydrogenase of Plasmodium knowlesi are specific to Plasmodium species

Polyclonal immune monkey serum raised against schizonts of Plasmodium knowlesi (H-strain) showed the presence of antibodies to lactate dehydrogenase (LDH) of P. knowlesi by immunodot enzyme staining method. The anti-LDH antibodies are most probably directed towards an epitope distinct from the catalytic site as shown by the specific enzyme staining of LDH after binding with antibody on nitrocellulose paper. These antibodies showed reactivity with LDH from different strains (H, P and W1 strains of P. knowlesi) and species (P. cynomolgi B, P. berghei, P. yoelii, P. falciparum and P. vivax) of malarial parasites but did not cross-react with three isoenzymic forms of mammalian LDH (A4, B4 and C4) as well as with LDH from some protozoan and helminth parasites. These findings suggest that the anti-LDH antibodies have defined specificity to Plasmodium spp.

Metabolism of benz[j]aceanthrylene (cholanthrylene) and benz[l]aceanthrylene by induced rat liver S9

The metabolites of benz[j]aceanthrylene (B[j]A) produced by incubation with liver S9 proteins from rats induced with Aroclor-1254 and phenobarbital have been identified as: trans-B[j]A-1,2-dihydrodiol, B[j]A-9,10-dihydrodiol, B[j]A-11,12-dihydrodiol, and 10-hydroxy-B[j]A. The major metabolite formed (58-60%) by both induced S9 preparations was trans-B[j]A-1,2-dihydrodiol, the cyclopenta-ring dihydrodiol while oxidation at the k-region or the proximal-bay region was minor. There were no statistical differences in individual or total B[j]A metabolite rates between the 2 induced S9 preparations. B[l]A was metabolized by Aroclor-1254 and phenobarbital induced rat liver S9 preparations to trans-B[l]A-1,2-dihydrodiol, B[l]A-7,8-dihydrodiol, and B[l]A-4,5-dihydrodiol. The major B[l]A metabolite formed (28-40%) by both induced S9 preparations was B[l]A-7,8-dihydrodiol, the k-region dihydrodiol. Cyclopenta-ring oxidation to trans-B[l]A-1,2-dihydrodiol was approximately 50% of that observed for k-region oxidation. Both induced S9s produced similar rates of B[l]A metabolites except for B[l]A-7,8-dihydrodiol formation which was higher for Aroclor-1254-induced S9.

Serum C-peptide after 6 months on glibenclamide remains higher than during insulin treatment

Serum C-peptide was measured fasting and 6 minutes after glucagon (1 mg given intravenously) in 49 patients with non-insulin-dependent diabetes mellitus, after 4 and 6 months of successive periods of treatment with insulin and oral hypoglycaemics (glibenclamide and metformin), given in random order. Glycaemic control was not significantly different on the two treatments, but C-peptide was much higher while the patients were on glibenclamide. We conclude that glibenclamide stimulates pancreatic insulin production even after 6 months treatment.

Mutagenicity of cyclopenta-fused isomers of benz(a)anthracene in bacterial and rodent cells and identification of the major rat liver microsomal metabolites

The microsomal metabolites and mutagenic activity of four cyclopenta-fused benz(a)anthracenes, benz(j)aceanthrylene [B(j)A], benz(e)aceanthrylene [B(e)A], benz(l)aceanthrylene [B(l)A], and benz(k)acephenanthrylene [B(k)A], have been studied. Aroclor 1254-induced rat liver microsomes metabolized B(j)A to B(j)A-1,2-dihydrodiol, B(j)A-9,10-dihydrodiol, B(j)A-11,12-dihydrodiol, and 10-hydroxy-B(j)A; B(e)A-1,2-dihydrodiol, B(e)A-3,4-dihydrodiol, and B(e)A-5,6-dihydrodiol; B(l)A to B(l)A-1,2-dihydrodiol, B(l)A-4,5-dihydrodiol, and B(l)A-7,8-dihydrodiol; and B(k)A to B(k)A-4,5-dihydrodiol and B(k)A-8,9-dihydrodiol. With each polycyclic aromatic hydrocarbon, metabolism occurred on the cyclopenta ring. All four isomers were active as gene mutagens in Salmonella typhimurium and in Chinese hamster V79 cells. In the S. typhimurium mutation studies, using Aroclor 1254-induced rat liver S9, B(j)A, B(e)A, and B(l)A required significantly less microsomal protein for maximal mutation response than B(k)A and B(a)P, suggesting a one-step activation mechanism, presumably on the cyclopenta-fused ring. B(j)A, B(e)A, and B(l)A were significantly more mutagenic than B(k)A and B(a)P in S. typhimurium. In the Aroclor 1254-induced rat liver S9-mediated V79 mutagenesis system, all four isomers were active, with B(l)A the most active. When Syrian hamster embryo cells were used as the metabolic activation component for V79 cells, only B(l)A produced a significant response and was equivalent in activity to B(a)P. A helical configuration for B(l)A is inferred from the identification of two trans-B(l)A-1,2-dihydrodiols, syn and anti, which have been synthesized, separated, and characterized. The metabolically formed dihydrodiol is anti-trans-B(l)A-1,2-dihydrodiol, and experimental evidence suggests that the metabolically formed B(l)A-1,2-oxide is the anti-isomer. Synthetic B(l)A-1,2-oxide was found to be a direct-acting mutagen in S. typhimurium and Chinese hamster V79 cells and is estimated to account for up to 40% of the mutagenic activity of the parent hydrocarbon. Therefore, certain cyclopenta-ring fusions on benz(a)anthracene appear to markedly increase its genotoxic and carcinogenic activities.

Intraventricular hemorrhage from ruptured aneurysm. Retrospective analysis of 91 cases

Intraventricular hemorrhage (IVH) from aneurysm rupture is generally considered to be of grave prognostic significance. Ninety-one cases have been studied retrospectively from seven medical centers. The overall mortality rate was 64%. The dramatically poor condition of these patients leads to their rapid admission to the hospital. Eighty-seven percent were admitted on Day 0 or 1, and more than half were classified neurologically as Grade 4 or 5. A multiple regression analysis explained 56% of the variance in survival, using the variables of ventriculocranial ratio (VCR), day of admission, diastolic blood pressure, location of aneurysm, associated intracerebral hematoma, age, grade on admission, sex, and systolic blood pressure. No patient with a VCR of more than 0.25, as calculated from the initial computerized tomography (CT) scan, survived. No patient whose smallest VCR was 0.23 or more survived. This ratio can be simply measured with a millimeter ruler from the CT scan. Patients with IVH usually had enlarged ventricles, even initially. The overall results suggest that early management of intracranial hypertension should be more generally considered, although even when this was done the prognosis was still guarded. The timing of surgery was not an important determinant of outcome, although a significant number of patients died awaiting surgery.

Timing of surgery for intracerebral hematomas due to aneurysm rupture

✓ Intracerebral hematomas (ICH) from aneurysm rupture are not rare and can now be diagnosed easily and accurately by computerized tomography. The authors have collected 132 such cases from 11 medical centers. Of these patients, 38% died prior to discharge from the hospital. Seventy-eight percent of cases were admitted to the neurosurgical services on Day 0 or 1 after rupture of the aneurysm; of these patients, 15% died without surgery, 28% had surgery and died postoperatively, and 57% were operated on and survived. Mortality rates were increased in patients who were hypertensive, had poor neurological grades, showed evidence of brain herniation, or had larger clots. If the patient lived beyond the first few days and did not have brain herniation, the timing of surgery was not of great consequence, although there was a tendency toward lower morbidity in earlier surgery. This was true despite the fact that earlier operations were carried out on an initially sicker group of patients. Ischemic deterioration attributed to vasospasm occurred in 26% of cases; even when deaths at the acute stage were excluded, it was no more common in patients with early than in those with late surgery. Morbidity and mortality rates were prohibitively high in operations consisting solely of evacuation of ICH without clipping of the aneurysm. Parietal hematomas were particularly dangerous, while those in the temporal lobe were associated with the best outcome. Since it is impossible to predict survival with a high degree of reliability, even when the prognostic indicators are known, the authors recommend that patients with a significant ICH have it removed as soon as possible and that their ruptured aneurysm be clipped at the same time.

Essential fatty acid deficiency in infants receiving parenteral nutrition

The clinical and biochemical features of essential fatty acid deficiency are described in an infant with gastroschisis who required long-term (6 mo) parenteral nutrition. The deficiency responded to therapy with Intralipid, topical sunflower oil, and breast milk. In a prospective study of three infants with gastroschisis, biochemical essential fatty acid deficiency developed in each during the first week of lipid-free parenteral nutrition; clinical signs of the deficiency were absent. The biochemical features were progressive in the one patient followed for 19 days, and were associated with a decrease in weight gain. Both the deficiency and weight gain were corrected by Intralipid. Biochemical essential fatty acid deficiency did not develop in three other gastroschisis infants who were given prophylactic Intralipid (two patients) or topical sunflower oil (one patient). We conclude that all infants on parenteral nutrition should receive a source of linoleic acid to prevent essential fatty acid deficiency.

Results for serum cholesterol and triglycerides by gas-liquid chromatography, as compared with a continuous-flow technique

We assessed the usefulness of gas-liquid chromatography forthe routine and reference measurement of cholesterol and triglycerides (triacylglycerols). Compared with results obtained by an AutoAnalyzer II method, correlation was good with both serum specimens (triglycerides, r = 0.88; cholesterol, r = 0.90) and lipoprotein fractions isolated by ultracentrifugation (triglycerides, r = 0.98; cholesterol, r = 0.98). However, none of the comparisons was completely free of analytical bias, and in general the AutoAnalyzer method underestimated the cholesterol value and overestimated triglycerides. The obvious advantage of the AutoAnalyzer is its greater analytical speed, but the chromatographic method appeared to be more accurate and precise and to suffer less from interfering substances, and in addition gave information about the cholesterol ester and triglyceride composition. We expect gas-liquid chromatography to be of major importance in the calibration of other analytical methods.

Results for serum cholesterol and triglycerides by gas-liquid chromatography, as compared with a continuous-flow technique

We assessed the usefulness of gas-liquid chromatography forthe routine and reference measurement of cholesterol and triglycerides (triacylglycerols). Compared with results obtained by an AutoAnalyzer II method, correlation was good with both serum specimens (triglycerides, r = 0.88; cholesterol, r = 0.90) and lipoprotein fractions isolated by ultracentrifugation (triglycerides, r = 0.98; cholesterol, r = 0.98). However, none of the comparisons was completely free of analytical bias, and in general the AutoAnalyzer method underestimated the cholesterol value and overestimated triglycerides. The obvious advantage of the AutoAnalyzer is its greater analytical speed, but the chromatographic method appeared to be more accurate and precise and to suffer less from interfering substances, and in addition gave information about the cholesterol ester and triglyceride composition. We expect gas-liquid chromatography to be of major importance in the calibration of other analytical methods.

Structure of some intact lipids of petrel stomach oils

The stomach or proventricular oils from 16 species of petrel have been analyzed and the carbon number distributions of the wax esters, triglycerides, and diacylglyceryl ethers are reported. The wax esters have been fractionated further into less and more polar species. To determine whether any intermolecular specificity existed, carbon number distributions for each lipid class were calculated, assuming random esterifications. The tirglyceride and diacylglyceryl ether compositions observed were all found to aggree closely with those calculated. The wax esters from three petrel species were found to have greater proportions of the middle range species with carbon numbers 34-38 than calculated. However, most of the lipids examined had random structures which have been found to be characteristic of marine sources. The results in general support the belief that the oils are derived directly from dietary sources rather than synthesis by the proventricular glands.

Production of 1,2-diacylglycerol and phosphatidate in human erythrocytes treated with calcium ions and ionophore A23187

1. When the ionophore A23187 and Ca2+ were added to normal human erythrocytes, the incorporation of 32P into phosphatidate was enhanced within 1 min, but there was only slight labelling of other phospholipids. 2. Labelling of phosphatidate in these cells did not continue to increase after about 20min at 37 degrees C; by this time, radioactivity in phosphatidate was about ten times higher inionophore A23187-treated cells than in controls. A net synthesis of phosphatidate was measured in response to the increase in intracellular Ca2+ concentration; the content of this phospholipid in the cell was increased by approximately 50%. 3. In the presence of 2.5 mM-Ca2+ a maximum effect was seen with about 0.5 mug of ionophore/ml. 4. The concentration of Ca2+ giving half-maximal labelling of phosphatidate in the presence of 10 mug of ionophore A23187/ml was about 10 muM. 5. A rapid decrease of ATP content in the cell occurred in ionophore-treated cells. 6. Labelling of phosphatidate appeared to be secondary to the production of 1,2-diacylglycerol in the cells; accumulation of 1,2-diacylglycerol was only seen after about 15 min. After 60 min, the 1,2-diacylglycerol content of the cells was five to seven times that of untreated control cells. 7. The change in the shape of erythrocytes treated with Ca2+ and ionophore appeared to be related to accumulation of 1,2-diacylglycerol. 8. The source of 1,2-diacylglycerol has not been definitely identified, but its fatty acid compositon was similar to that of phosphatidylcholine. However, it has an unusually high content of hexadecenoic acid, a fatty acid not common in the major erythrocyte phospholipids. 9. Accumulation of 1,2-diacyglycerol also occurred in energy-starved cells, even in the absence of calcium; in this case it appeared to be produced by phosphatidate breakdown.

Aortic washout of 125I compounds in atherosclerotic and normal rabbits

An in vivo rabbit model is described for the study of aortic washout of 125I tagged compounds. Washout is compartmental and in sequence from the lumen, aortic wall, and periaortic fat. Toluene-azo-naphthol (TAN) affixed chiefly to periaortic fat. A double isotope method with TAN plus a cholesterophilic substance is suggested for the assay of atherosclerosis in situ.

Milk triglycerides: the degree of non-random associations of fatty acids

Published data are available for the fatty-acid compositions and molecular-weight distributions of triglycerides in milk and adipose tissue from the guinea-pig, rat, mouse and rabbit, and in milk from the human, cow, mink and hamster. These data have been used to calculate the extent of non-random associations of fatty acids of different chain lengths in these triglycerides.

The results support, in general, the concept of non-correlative acylation, i.e. that during the biosynthesis of these triglycerides, fatty acids already present on the glycerol backbone do not influence the selective acylation of subsequent fatty acids. However, milk triglycerides from these animals show varying degrees of intermolecular specificity which can be explained in terms of positional specificity of fatty acids on the glycerol backbone.

Separation of mono- and diglycerides by gas--liquid chromatography

The parameters affecting the separation and quantification of trimethylsilyl ethers of mono- and diglycerides have been investigated by gas-liquid chromatography with QF-1 and SE-30 as stationary phases and a flame ionization detector. Results have been compared with those obtained earlier for triglycerides. The isothermal characteristics of a range of trimethylsilyl ethers of mono- and diglycerides on both stationary phases showed that log retention volume was directly proportional to carbon number and inversely proportional to absolute temperature. However, glyceride derivatives with lower carbon numbers deviated from these relationships. By using various rates of programmed temperature rise, we have determined the elution temperatures (Kelvin scale) of the mono- and diglyceride trimethylsilyl ethers relative to that of glycerol trilaurate. The "carbon equivalent of a trimethylsilyl group" is defined and shown to be useful in comparing the chromatographic properties of different glyceride classes. Weight and molar correction factors have been obtained and used to analyze diglycerides derived from egg and bovine brain lecithins.

Human milk: Quantitative gas-liquid chromatographic analysis of triglyceride and cholesterol content during lactation

Gas-liquid chromatography has been used to follow changes in the triglyceride composition of human colostrum and milk from one donor during the first 10 days postpartum and to compare the compositions obtained with those at later stages of lactation.New triglycerides of low molecular weight appeared during the first 5 days postpartum. Lower molecular weight triglycerides (<C(48)) continued to increase until the eighth day. Triglyceride C(48) and total cholesterol content remained almost constant during the period of the study.Comparison of triglyceride fatty acid composition on the third, sixth, and ninth days postpartum showed considerable specificity in all cases, but a tendency for randomization to occur as lactation proceeded.The advantage of triglyceride over fatty acid analysis for this type of investigation is that in the former, new molecules appear. In the latter, only changes in the proportions of fatty acids occur.

Separation of triglycerides by gas-liquid chromatography

The parameters affecting the separation and quantification of triglycerides by gas-liquid chromatography have been investigated with the use of QF-1 and SE-30 as stationary phases and a flame ionization detector. The isothermal characteristics of a wide variety of triglycerides (carbon number 6 to 60) on both columns show that long retention volume is directly proportional to carbon number and inversely proportional to absolute temperature. Isothermal retention indices of some triglycerides are given, as are column efficiencies (in terms of theoretical plates and ability to separate closely related triglycerides). When various rates of programmed temperature rise are used, retention indices have been found to be less useful than absolute or relative elution temperatures. The elution temperatures of triglycerides of carbon number 6 to 54 have been determined relative to that of trilaurin. Under optimal separation conditions weight and molar correction factors can be obtained. Triolein and tristearin have been partially separated, as have certain triglycerides that have the same carbon number but widely different fatty acids. The natural triglycerides of human milk fat have been separated.

Quantitative gas-liquid chromatographic analysis of rodent milk triglycerides

A comparison has been made of the milk and adipose tissue triglycerides of rabbits and guinea pigs provided with one diet and of rats and mice provided with another. Both intact triglycerides and component fatty acids were analyzed by gas-liquid chromatography. Good correlation of the data obtained by the two techniques was obtained by calculating the average chain length of the fatty acid moieties. Little difference was found in the triglyceride composition of the adipose tissue of the different species. However, wide variation in the triglyceride composition of the milk was found between the species: the average fatty acid chain length in milk was 11.7 for rabbits, 14.2 for rats, 15.3 for mice, and 17.2 for guinea pigs. The corresponding values for adipose tissue were in the range 16.9-17.4 in all animals. The significance of enzymes that synthesize short-chain fatty acids in mammary gland is discussed.