Hemobilia in a child with liver abscess

Hemobilia in children is rare and has so far been described only as a complication of blunt abdominal trauma. A case of hemobilia secondary to liver abscess treated successfully by selective arterial embolization is described. Hemobilia should be considered in any case of gastrointestinal hemorrhage before any operative intervention is undertaken.

Percutaneous transluminal angioplasty for ischaemic arterial disease of the lower extremities

We attempted percutaneous transluminal angioplasty (PTA) in 43 patients with limb-threatening ischaemia (rest pain, nonhealing ulcer or gangrene) or lifestyle-limiting claudication. Of the 51 lesions dilated, 31 were in iliac, 12 in femoral, 6 in popliteal and 2 in tibial arteries. Overall primary success rate was 90.2 percent (46/51); 96.8 percent (30/31) in iliac, 83.3 percent (10/12) femoral, 66.7 percent (4/6) popliteal and 100 percent (2/2) in tibial arteries. Marked relief of ischaemic symptoms and increase in ankle-arm pressure index from 0.45 +/- 0.14 to 0.94 +/- 0.23 (P less than 0.005) were seen in the 39 patients with initial technical success. Three (6.9%) patients had minor complications. On 1-33 (mean 13.4 +/- 7.5) months follow up, 89.5 percent patients showed continued clinical improvement as well as improvement in noninvasive parameters of lower limb perfusion. We conclude that angioplasty of iliac, femoral, popliteal and tibial arteries is a highly effective and safe procedure to revascularize the ischaemic lower extremity.

Nonrandomness in prebiotic peptide synthesis

We have synthesized and studied the properties of phosphoanhydrides of alanine with guanosine monophosphate, uridine monophosphate, and adenosine monophosphate. This series of compounds allowed us to investigate the specificity of peptide bound formation in a reaction that could have taken place on the prebiotic earth. We asked whether the intrinsic reactivity of the amino acids, the nature of the nucleotide in the anhydride, or the complementary polynucleotide template influences the specificity of the peptide synthesis reaction. We observed that the differential reactivity of the amino acids results in nearest-neighbor preferences during the peptide synthesis, whereas the nature of the nucleotides and the presence of complementary polynucleotides had no influence on the specificity. These results suggest that some peptides would have been more abundant than others on the prebiotic earth and have implications for the study of the origins of the genetic code and protein synthesis.

Randomised two way crossover comparison of the effects of six weeks propranolol and acebutolol therapy on plasma lipid profiles in patients with hypertension or ischaemic heart disease

The effect of propranolol and acebutolol therapy on serum lipoproteins was studied in thirty patients (mean age 43.9 +/- 8.7 years) with essential hypertension and/or stable myocardial ischaemia. Patients received six weeks therapy with propranolol (80-160 mg per day) and acebutolol (400-800 mg per day) each in random order and were changed over from one to the other beta-blocker after 6 weeks therapy. On propranolol treatment there was no significant effect on total cholesterol and LDL-cholesterol but the concentration of serum triglycerides (94.2 +/- 37.7 to 129.1 +/- 41.2 mg/dl) and VLDL cholesterol (18.9 +/- 7.8 to 26.1 +/- 8.1 mg/dl) significantly increased, concentration of HDL cholesterol (49.5 +/- 9.4 to 42.4 +/- 8.7 mg/dl) significantly decreased (p less than 0.01). Atherogenic index also worsened from 4.17 +/- 0.48 to 5.15 +/- 0.54 (p less than 0.05) on propranolol therapy. Acebutolol therapy, on the other hand, produced no significant change in the concentration of total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol and VLDL cholesterol.

Evaluation of aortic aneurysms and dissection of aorta by intravenous digital subtraction angiography

Intravenous (IV) digital subtraction angiography (DSA) was performed in 12 patients with suspected aortic aneurysm/dissection. Bolus injection of 30-40 ml of contrast in mid right atrium/main pulmonary artery at a flow rate of 18-20 ml/sec. during DSA accurately localised the site and extent in all 7 patients of aortic aneurysm and in 4 patients of aortic dissection. In one patient, radiological opacity was unrelated to aorta. There were no complications. IV-DSA should be the preferred mode of evaluation for aortic aneurysm and dissection of aorta.

Prognostic significance of pre discharge one hour electrocardiographic monitoring in patients recovering from acute myocardial infarction

During a 15 months period, 97 patients with AMI were monitored continuously at hospital discharge for one hour. The VPCs or no VPC noted during this period of continuous monitoring were correlated with subsequent cardiac events during one year follow up. Patients with complicated VPCs had a significantly higher incidence of cardiac deaths and non-fatal re-infarctions during one year follow up (54.5%) as compared to patients with no VPCs (6.5%) (p less than .001). Patients with higher grades of VPCs had more complicated course (30.3% to 66.7% for Lown Grade II to IV) as compared to 6.5% and 20.8% for grade Lown O and I. Though, the results of this 1 hour continuous monitoring at hospital discharge are not as sensitive as with ambulatory Holter monitoring as is evident from this study where complicated VPCs were detected in 11.4% patients vs. 33% with Holter monitoring, it could be a useful tool in institutions where the facility of Holter monitoring does not exist.

Follow-up of balloon aortic valvuloplasty in young adults--a combined hemodynamic and Doppler echocardiographic study

Percutaneous Balloon Valvuloplasty was performed in 25 patients with severe aortic stenosis (Aortic valve area index: 0.23 to 0.70, mean 0.36 +/- 0.11 cm2/m2). The mean age was 23 +/- 15 (range 6-66) years, and majority (n = 18) had noncalcific valves. Valve morphology was bicuspid in 14, tricuspid in 6 and indeterminate in 5. Valvuloplasty resulted in a fall of peak systolic gradient (PSG) from 112 +/- 35 to 34 +/- 16 mmHg (p less than 0.001), and an increase in aortic valve area (index) (AVAI) from 0.36 +/- 0.11 to 0.82 +/- 0.43 cm2/m2 (p less than 0.001). Follow-up data at 16 +/- 6 months were available for 18 patients, 80 per cent of whom registered symptomatic improvement. Repeat catheterization, performed in 12 cases, showed increase of PSG to 53 +/- 22 mmHg and a fall in AVA (1) to 0.62 +/- 0.24 cm2/m2, as compared to the results immediately following the procedure. In addition, 3 patients had their valve areas estimated by doppler echocardiography. Forty-six per cent of these 15 patients (n = 7) showed evidence of restenosis. Four out of these 7 cases had calcific valves, whereas none of the patients who had sustained improvement had calcification. Tricuspid morphology was present in 50 per cent of the group with sustained improvement, as compared to 20 per cent of the group that restenosed. Our preliminary data shows sustained hemodynamic improvement after balloon dilatation in young patients with severe aortic stenosis with noncalcific and tricuspid aortic valve.

Quantitative assays based on the use of replicatable hybridization probes

Amplifiable hybridization probes--molecules with a probe sequence embedded within the sequence of a replicatable RNA--will promote the development of sensitive clinical assays. To demonstrate their utility, we prepared a recombinant RNA that contained a 30-nucleotide-long probe complementary to a conserved region of the pol gene in human immunodeficiency virus type 1 (HIV-1) mRNA. Test samples were prepared, each containing a different number of HIV-1 transcripts that served as simulated HIV-1 mRNA targets. Hybridizations were carried out in a solution containing the chaotropic salt, guanidine thiocyanate. Probe-target hybrids were isolated by reversible target capture on paramagnetic particles. The probes were then released from their targets and amplified by incubation with the RNA-directed RNA polymerase, Q beta replicase (EC 2.7.7.48). The replicase copied the probes in an exponential manner: after each round of copying, the number of RNA molecules doubled. The amount of RNA synthesized in each reaction (approximately 50 ng) was sufficient to measure without using radioisotopes. Kinetic analysis of the reactions demonstrated that the number of HIV-1 targets originally present in each sample could be determined by measuring the time it took to synthesize a particular amount of RNA (the longer the synthesis took, the fewer the number of targets originally present). The results suggest that clinical assays involving replicatable hybridization probes will be simple, accurate, sensitive, and automatable.

Prevalence and clinical significance of coronary artery ectasia (an angiographic study)

Coronary cine-angiograms of 1,042 patients were reviewed for the presence of ectasia of major coronary arteries. Ectasia or irregular dilatation of the coronary artery was defined as 1.5 times diffuse or segmental dilatation as compared to segment of normal caliber coronary artery. Forty-one (3.9%) patients were found to have diffuse or localised coronary artery dilatations with segments of normal caliber throughout the length of major vessels. Mean age of the patients was 52 years, and majority were males (39, 95%). Right coronary artery (RCA) and left circumflex (Cx) were involved in 23 (56%) each, left anterior descending (LAD) in 15 (37%), obtuse marginal in 4 (10%) and left main in 2 (5%). Multiple vessel involvement was present in 21 (51%). Evidence of myocardial infarction was present in 21 (51%). Major risk factors were not different from the patients with coronary artery disease without ectasia.

Quantitative assays based on the use of replicatable hybridization probes

Amplifiable hybridization probes--molecules with a probe sequence embedded within the sequence of a replicatable RNA--will promote the development of sensitive clinical assays. To demonstrate their utility, we prepared a recombinant RNA that contained a 30-nucleotide-long probe complementary to a conserved region of the pol gene in human immunodeficiency virus type 1 (HIV-1) mRNA. Test samples were prepared, each containing a different number of HIV-1 transcripts that served as simulated HIV-1 mRNA targets. Hybridizations were carried out in a solution containing the chaotropic salt, guanidine thiocyanate. Probe-target hybrids were isolated by reversible target capture on paramagnetic particles. The probes were then released from their targets and amplified by incubation with the RNA-directed RNA polymerase, Q beta replicase (EC 2.7.7.48). The replicase copied the probes in an exponential manner: after each round of copying, the number of RNA molecules doubled. The amount of RNA synthesized in each reaction (approximately 50 ng) was sufficient to measure without using radioisotopes. Kinetic analysis of the reactions demonstrated that the number of HIV-1 targets originally present in each sample could be determined by measuring the time it took to synthesize a particular amount of RNA (the longer the synthesis took, the fewer the number of targets originally present). The results suggest that clinical assays involving replicatable hybridization probes will be simple, accurate, sensitive, and automatable.

PEG- and electroporation-induced transformation in Nicotiana tabacum: influence of genotype on transformation frequencies

Experimental parameters for direct gene transfer with recombinant DNA encoding neomycin phosphotransferase II (NPTII) under control of eukaryotic expression signals were established. The introduced gene was shown by the growth of transformants on media containing kanamycin, by genomic blotting and by assaying NPTII activity. Leaf protoplasts from three green genotypes of varieties xanthii and petit havanna, and from four plastome-encoded albino genotypes of Nicotiana tabacum were analyzed with respect to cell division kinetics and yield of kanamycin-tolerant colonies after direct gene transfer. No clear correlation was found between the time of onset of cell division and transformation frequency.

Detection, frequency and clinical significance of silent myocardial ischaemia in patients with chronic stable angina

Forty-two patients (mean age 50 years) with chronic stable angina pectoris were subjected to exercise treadmill testing, coronary arteriography and left ventricular cineangiography. Twenty-one of these patients also underwent Holter monitoring for 24 hours. On exercise treadmill testing, angina was the endpoint in 24 (57%), while 18 (43%) developed significant ST segment depression without symptoms. Holter monitoring in 27 patients revealed a total of 248 episodes of myocardial ischaemia of which 210 (84%) were asymptomatic. ST segment depression at 80 mS from J point varied from 1 to 4 mm, and the average duration of ischaemic episodes during Holter monitoring was 9 minutes (range 30 seconds to 1 hour). Heart rate during the ischaemic episodes varied between 65-85 beats/minute. Coronary angiography revealed triple vessel disease in 22 (52%) and double vessel and single vessel involvement in 10 (24%) each. Left ventricular ejection fraction was less than 50% in only 3 (7%) patients. Thus silent myocardial ischaemia is detected frequently in patients with angina pectoris. It occurs during routine daily activity, and on exercise. Heart rate at which silent myocardial ischaemia occurs is much less during daily activity as compared to exercise induced ischaemia. All patients who were detected to have silent myocardial ischaemia had significant coronary artery disease. These findings are of prognostic and therapeutic value.

An arteriographic assessment of renal vasculature in young patients with essential hypertension

Twenty-five patients below the age of 40 years with Uncomplicated hypertension underwent selective renal arteriography to assess the involvement of interlobar and arcuate arteries. Renal vasculature was abnormal in all 25 patients. Patients with severe hypertension had markedly abnormal renal vasculature. None of the patients with mild hypertension had severe vascular involvement. Functional significance of these arteriographic abnormalities is discussed.

Percutaneous transluminal balloon angioplasty of the aorta in patients with aortitis

Four patients with aortitis and stenotic lesions of the aorta were successfully treated by percutaneous transluminal balloon angioplasty. The peak systolic gradient across the constrictions decreased from 82.5 +/- 35.7 to 37.5 +/- 18.5 mm Hg immediately after dilatation. Repeat angiography in the first three patients performed 2 months later showed a further decrease in the gradient to 13.8 +/- 9.5 mm Hg. There were no complications during or after the procedure, and all the patients have shown remarkable symptomatic relief during the follow-up.

Toxic effects of chromium in a freshwater teleost fish, Channa punctatus

The effect of in vivo exposure to a sublethal concentration of hexavalent chromium for 30 days on blood glucose, blood liver and muscle lactic acid; haemoglobin, liver and muscle glycogen; and activities of lactate dehydrogenase (LDH), pyruvate dehydrogenase (PHD) and succinate dehydrogenase (SDH) in liver, muscle, kidney, gills and brain has been studied. Blood glucose and lactic acid levels were elevated. Liver glycogen was depleted but muscle glycogen content increase. The activities of LDH and SDH in liver were elevate. Elevation was also observed in muscle LDH and PDH activities, showing that the rate of glycolysis is increased. No change was noted in haemoglobin content of blood or in the activities of the three dehydrogenases in kidney and gills.

Origins of translation: the hypothesis of permanently attached adaptors

A mechanism for prebiotic translation is proposed in which primeval transfer-RNA (adaptors) are assumed to be permanently associated with messenger nucleic acid molecules. Residual 'fossil' evidences are found to be present within the base sequences of contemporary tRNAs, suggesting the existence of inter-primal-tRNA interactions necessary for the mechanism. The structure of proposed primal-tRNA is such that it can not only choose its own amino acid in the absence of aminoacyl synthetase, but can also associate nonspecifically with adjacent primal-tRNA molecules attached to the neighbouring codons. Such associations can give rise, through cooperative binding between message and adaptors to the 'static template surfaces' which can direct translation of nucleotide sequences into those of amino acids. The origins of ribosomes and contemporary genetic code are suggested by this hypothesis. Proposed structures and processes are thermodynamically compatible. The approximate date of occurrence of the proposed system is calculated, which is consistent with the period of occurrence of the earliest organism with ribosomes.

Effect of exogenous fatty acids on growth, membrane fluidity, and phospholipid fatty acid composition in yeast

The growth response of a double-mutant fatty acid auxotroph of yeast Saccharomyces cerevisiae to exogenous saturated fatty acids of a homologous series from 12:0 to 16:0, each supplied with oleate, linoleate, linolenate, or cis-delta 11-eicosenoate, cannot be explained in terms of the efficiency of incorporation of the fatty acids into phospholipids or alteration of membrane fluidity. There is, however, a negative correlation between growth and levels of 12:0 plus 13:0 in phospholipids, as well as a positive correlation between growth and levels of 14:0, 15:0, and 16:0. We, therefore, conclude that the predominant factor in these phospholipid fatty acyl chain modifications is maintenance of an optimal concentration of C14:0 through C16:0 in phospholipids of this organism.

A novel form of vitamin B-12 and its derivatives

A new isomeric form of cobalamins is reported. The conversion of cobalamin to cobalamin (the new form) is achieved by substituting the benzimidazole base by a less bulky group like H2O or CN- and modest thermal treatment. The back conversion of adenosylcobalamin to the corresponding regular form occurs in the "base-off" form at room temperature. It seems that the corrin ring becomes quite flexible in the "base-off" form and the freer axial movement of the cobalt atom flips the corrin ring into a different conformation. The change in conformation is borne out by subtle changes in the proton magnetic resonances on the corrin ring and the base, and very marked variation in the emission Mössbauer spectra. The latter is indicative of appreciable changes in the spatial conformation in the immediate vicinity of the central metal atom. The ultraviolet-visible and infrared spectra of cobalamin are indistinguishable from those of its corresponding regular form. The new conformational isomeric species is present as an impurity in all commercially available cobalamins (including pharmaceutical preparations). It raises the question whether the cobalamins' constitute the real biologically active anti-anemic factor in humans.

Emission Mössbauer studies of some organocobalamins

Subtle changes in the Mössbauer parameters are observed while going from methyl- to ethyl- to adenosylcobalamin, and also when the "base" is detached from the cobalt. The observation of these changes demonstrates that the Co-C bond, among others, remains intact after the Auger event, accompanying the electron-capture decay of the cobalt-57. The differences between ethylcobalamin and the other two organocobalamins in the magnitude of the quadrupole splittings have been interpreted on the basis of the sigma-donating tendency of the organic moiety and the Co-C bond length. The latter is presumably determined by the steric hindrance offered to the group in approaching the cobalt atom. The ethyl- and adenosylcobalamins in their "base-off" form exhibit a larger quadrupole splitting than the corresponding "base-on" form. In the "bas-off" form, the cobalt atom is perhaps raised above the mean plane of the four equatorial nitrogen atoms of the corrin ring, which may result in the diminution of the delocalization of the 3dpi electron density. The higher population of dpi orbitals and the enhanced metallic character of the dz2, resulting from shrinkage of the Co-C bond length, enhances the magnitude of the quadrupole splitting.

Emission Mössbauer study of the stereochemical trigger that initiates cooperative interaction of hemoglobin subunits

An important feature of Perutz's trigger mechanism for cooperativity in the reversible oxygenation of hemoglobin (Hb) is the tension along the histidine--metal linkage in deoxyHb and deoxycobaltohemoglobin (deoxy CoHb), supposedly due to the pull exerted by the globin on the metal atom. We have attempted to verify the existence of this pull by studying the emission Mössbauer spectra of deoxy 57CoHb and oxy 57 CoHb at different temperatures. The emission Mössbauer spectrum for none of the cobalt Hbs agrees with the absorption spectrum of the corresponding iron analog and, moreover, the spectrum of deoxy 57CoHb is characteristic of the intermediate-spin iron. These observations indicate that the daughter 57Fe atom is "frozen" almost in the same spatial situation as that of the parent 57Co. The protein is apparently holding the cobalt atom in position rather rigidly and, after the electron-capture decay of the 57Co atom, the protein does not permit the daughter 57Fe to move to a position characteristic of the iron atom.