Effect of metoprolol and diltiazem on the total ischaemic burden in patients with chronic stable angina: a randomized controlled trial

We conducted a randomised controlled trial to study the effects of metoprolol and diltiazem on the total ischaemic burden--sum of symptomatic and silent myocardial ischaemia, in 146 patients with stable angina pectoris. One-hundred thirty-four completed the study protocol. Sixty-eight patients received metoprolol (100 mg twice daily, n = 52, 50 mg twice daily, n = 16) while 66 received diltiazem (90 mg three times daily, n = 50, 60 mg three times daily, n = 16). The drugs were given for 4 weeks. The primary outcome variables were frequency and duration of total ischaemic burden, silent and symptomatic myocardial ischaemia. These were measured on 48 h of Holter monitoring. The reductions in duration and frequency of total ischaemic burden by metoprolol, 76% and 40%, respectively, were significantly higher than by diltiazem, 43% and 24%, respectively (P < 0.01 and P < 0.02). The frequency and duration of silent myocardial ischaemia, which constituted more than 80% of the total ischaemic burden in the two groups showed similar results. However, the reduction in frequency of symptomatic myocardial ischaemia only was significantly greater by metoprolol (63% than diltiazem (24%) as the difference in reduction of duration of symptomatic ischaemia was insignificant (85% vs. 75%; P > 0.05). Whether a greater reduction of total ischaemic burden by metoprolol as compared to diltiazem has any implications for prognosis in patients with chronic stable angina remains to be established.

Etiology of isolated mitral regurgitation: a clinico-echocardiographic study

One hundred and ninety two consecutive patients with isolated mitral regurgitation (MR) with an audible murmur were studied for determination of etiology. There were 95 males & 97 females (mean age 24.5 +/- 10.8 years; range 13 to 58 years) with 102 patients in NYHA classes I and II, 81 in class III and 9 in NYHA class IV. The etiological grouping was: rheumatic 74 (38.5%), probable rheumatic 28 (15%), mitral valve prolapse 26 (13.5%), dilated cardiomyopathy 15 (8%), infective endocarditis 12 (6%), isochaemic heart disease 10 (5%), miscellaneous group (including rupture chordae tendinae, aortoarteritis etc) 9 (4.5%) and patients with indeterminate etiology 18 (9.5%). Etiology could be determined in 174 out of 192 cases. The clinical methods combined with echocardiography were helpful in 79 cases while echocardiography alone could diagnose etiology in 89 cases. Clinical features alone gave the diagnosis in 6 patients. The findings of gross morphology of the surgically removed mitral valves in 30 patients of this study were similar to their pre-operative etiologic diagnosis based on clinical and echocardiographic features. These findings may be of value in planning treatment and prophylactic strategies in cases of isolated MR.

Atrio-ventricular regurgitations in constrictive pericarditis: incidence and post-operative outcome

We studied 33 surgically proven cases of constrictive pericarditis during the period 1989-1991 by color Doppler echocardiography and angiography to look for incidence and postoperative outcome of atrioventricular regurgitation. The mean age was 27.2 + 16.5 years (21 males, 12 females). There was a very high incidence of mitral (79%, trivial in 13, mild in 11 and moderate in 2) and tricuspid (73%, trivial in 7, mild and moderate in 6 each and severe in 5) regurgitation. There was good correlation between 'color Doppler' and angiography for detection and quantification of these regurgitations (r = 0.89 for mitral and 0.76 for tricuspid regurgitation, respectively). There were no preoperative clinical or hemodynamic predictors for the incidence or severity of these regurgitations. Immediate postoperative (7-10 days) evaluation by color Doppler did not show any change in these regurgitations. A follow-up study (by color Doppler and angiography) in 18 patients at a mean period of 229 + 105 days revealed regression of these regurgitations by at least 1 grade in 50% of patients. Patients with persisting regurgitations had persisting hemodynamic abnormality and relatively longer duration of symptoms. The presence of atrio-ventricular regurgitations should not be taken as evidence favoring diagnosis of restrictive cardiomyopathy and against that of constrictive pericarditis. The mechanism of these regurgitations is not clear to us.

Extensive calcification of pulmonary arteries with left-to-right shunting across the arterial duct

Extensive calcification of the pulmonary trunk extending to the arterial duct is described in a young adult. The unusual feature was the presence of restriction of the duct with only left-to-right shunting. The rarity of this condition and its surgical importance is emphasized.

Maize mutants and variants altering developmental time and their heterochronic interactions

It is useful to envision two fundamentally different ways by which the timing of plant development is regulated: developmental stage-transition mechanisms and time-to-flowering mechanisms. The existence of both mechanisms is indicated by the behavior of various mutants. Shoot stage transitions are defined by dominant mutants representing at least four different genes; each mutant retards transitions from juvenile shoot stages to more adult shoot stages. In addition, dominant leaf stage-transition mutants in at least seven different genes have similar phenotypes, but the leaf rather than the shoot is the focus (and at least two of these genes encode homeodomain proteins.) One mutant, Hairy sheath frayed 1-O (Hsf1-O) simultaneously affects shoot and leaf; this mutant's behavior initiated our interest in plant heterochronism. The second type of timekeeping involves time-to-flowering. As with most plant but not animal species, cultivars of the maize species vary greatly for the time-to-flowering quantitative trait: between 6 and 14 weeks is common. It is via the 'slipping time frames' interaction that takes place between stage-transition mutants and time-to-flowering genetic backgrounds that unexpected and radical phenotypes occur. We see a reservoir of previously unsuspected morphological possibilities among the few heterochronic genotypes we have constructed, possibilities that may mimic the sort of variation needed to fuel macroevolution without having to posit (as done by Goldschmidt) any special macromutational mechanisms.

Effect of endosulfan on thyroid physiology in the freshwater catfish, Clarias batrachus

Effects of endosulfan on thyroid physiology have been studied in the female freshwater catfish. Clarias batrachus during the pre-spawning and spawning phases of its annual reproductive cycle. Effects of endosulfan varied with the length (96 h and 16 days) of exposure, reproductive status of the fish and organ. The 96-h endosulfan exposure significantly increased the level of thyroxine (T4) in serum and pharyngeal thyroid follicles concurrent with induction of peroxidase activity. However, triiodothyronine (T3) level and T3/T4 ratio decreased in serum and pharyngeal thyroid gland. No change was noticed in any of these parameters in the anterior kidney but in the posterior kidney endosulfan reduced T3 and T3/T4 ratio without affecting T4 levels and peroxidase activity. Sixteen days of endosulfan treatment also had a similar impact, except that it did not influence the studied parameters in pharyngeal thyroid.

The developmental gene Knotted-1 is a member of a maize homeobox gene family

The Knotted-1 (Kn1) locus is defined by several dominant gain-of-function mutations that alter leaf development. Foci of cells along the lateral veins do not differentiate properly, but continue to divide, forming outpocketings or knots. The ligule, a fringe normally found at the junction of leaf blade and sheath, is often displaced and perpendicular to its normal position. The phenotype is manifested in all cell layers of the leaf blade, but is controlled by a subgroup of cells of the inner layer. Mutations result from the insertion of transposable elements or a tandem duplication. We show that the Kn1 gene encodes a homeodomain-containing protein, the first identified in the plant kingdom. Sequence comparisons strongly suggest that Kn1 acts as a transcription factor. Here we use the Kn1 homeobox to isolate other expressed homeobox genes in maize. The Kn1 homeobox may permit the isolation of genes that, like animal and fungal counterparts, regulate cell fate determination.

Pesticides induced changes in circulating thyroid hormones in the freshwater catfish Clarias batrachus

1. Effects of endosulfan, malathion and carbaryl on circulating T4, T3 and T3/T4 ratio in the freshwater catfish, C. batrachus have been studied during reproductively active phases, i.e. vitellogenic and post-vitellogenic phases of its annual reproductive cycle. 2. Endosulfan provoked a significant increase in T4 and a decrease in T3 as well as the T3/T4 ratio. 3. Malathion decreased T3 and T3/T4 ratio without altering the level of T4 in circulation. 4. Carbaryl caused a decline in the level of T4 and an elevation in T3 and T3/T4 ratio.

Chronic toxicity of styrene maleic anhydride, a male contraceptive, in rhesus monkeys (Macaca mulatta)

A newly developed male contraceptive, styrene maleic anhydride (SMA), was injected in the vas deferens of male rhesus monkeys for safety evaluation at the dose of 100 mg (contraceptive dose, CD), 250 mg (CD x 2.5) and 500 mg (CD x 5.0), and the monkeys were kept under observation for one year. The observed behavioural, haematological, biochemical and histopathological parameters in treated monkeys were comparable to controls. The results suggest the polymer SMA to be safe up to 5 times CD in monkeys.

Mutant characters of knotted maize leaves are determined in the innermost tissue layers

Knotted (Kn1), a dominant mutation in maize, perturbs normal leaf development. Mutant leaves have localized regions of extra growth called knots and, in addition to the normal ligule, ectopic fringes of ligule are found on the leaf blade. Previous clonal analysis showed that the epidermal genotype was immaterial in knot formation. To establish which inner leaf layer was required for formation of knots and ectopic ligule we used a closely linked albino mutation to mark X-ray-induced clonal sectors of wild type (kn) tissue in Kn1 plants. The sectors examined frequently changed in composition of layers in the leaf both transversely and longitudinally. We present results that show that both mutant characters are determined in the middle mesophyll-bundle sheath (MMBS) layer. We show that a lateral vein can produce a knot when only half the MMBS layer around the lateral vein contains the mutant gene. We also show that the ectopic ligule in Kn1 has contributions from both the adaxial epidermal and adaxial mesophyll layer.

RecA protein of Escherichia coli has a third essential role in SOS mutator activity

The DNA damage-inducible SOS response of Escherichia coli includes an error-prone translesion DNA replication activity responsible for SOS mutagenesis. In certain recA mutant strains, in which the SOS response is expressed constitutively, SOS mutagenesis is manifested as a mutator activity. Like UV mutagenesis, SOS mutator activity requires the products of the umuDC operon and depends on RecA protein for at least two essential activities: facilitating cleavage of LexA repressor to derepress SOS genes and processing UmuD protein to produce a fragment (UmuD') that is active in mutagenesis. To determine whether RecA has an additional role in SOS mutator activity, spontaneous mutability (tryptophan dependence to independence) was measured in a family of nine lexA-defective strains, each having a different recA allele, transformed or not with a plasmid that overproduces either UmuD' alone or both UmuD' and UmuC. The magnitude of SOS mutator activity in these strains, which require neither of the two known roles of RecA protein, was strongly dependent on the particular recA allele that was present. We conclude that UmuD'C does not determine the mutation rate independently of RecA and that RecA has a third essential role in SOS mutator activity.

Echocardiographic demonstration of resolving intrapericardial mass in tuberculous pericardial effusion

A patient with tuberculous pericardial effusion is described who presented with cardiac tamponade. Subsequent to pericardiocentesis, a large echodense intrapericardial mass was observed which disappeared completely with antituberculous chemotherapy. The resolution of the mass suggests that it was a conglomeration of fibrinous exudates deposited in the pericardial cavity. Presence of such exudates should not be considered an indication for surgical intervention.

Digoxin or verapamil or metoprolol for heart rate control in patients with mitral stenosis--a randomised cross-over study

The effect and choice of a drug to control heart rate for symptomatic improvement in patients with isolated mitral stenosis with normal sinus rhythm (n = 10) or atrial fibrillation (n = 10) were studied. Digoxin (0.25-0.5 mg daily), metoprolol (50-100 mg twice a day) and verapamil (40-80 mg three times a day) were evaluated for this purpose. An open randomised cross-over design was followed. The efficacy of a drug was evaluated by: (1) subjective improvement on a visual analog scale, and (2) objective improvement on repeated multi-stage symptom-limited treadmill exercise. In patients with sinus rhythm greater than or equal to 50% subjective improvement was seen in 90%, 40% and nil with metoprolol, verapamil and digoxin, respectively. The total work done by these patients was 1008 +/- 541 kpm (control), 2869 +/- 1418 kpm on metoprolol, 2369 +/- 884 kpm on verapamil and 1654 +/- 918 kpm on digoxin. In patients with atrial fibrillation greater than or equal to 50% subjective improvement was seen in 80%, 40% and 30% with verapamil, metoprolol and digoxin, respectively. The total work done by these patients was 555 +/- 232 kpm (control), 1379 +/- 553 kpm on verapamil, 1251 +/- 575 kpm on metoprolol and 716 +/- 340 kpm on digoxin. The degree of improvement on a drug appeared to be a function of its ability to control resting and exercise heart rates in two different rhythms in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical correlates of acute right ventricular infarction in acute inferior myocardial infarction

Right ventricular infarction was diagnosed on the basis of ST-segment elevation greater than or equal to 1 mm in at least one right precordial lead (V3R-V6R) in 20 of 50 patients with first acute inferior myocardial infarction. Seventy five percent of these had ST elevation in 2 or more right precordial leads. Giddiness and hiccups were more common amongst such patients (P less than 0.05). Signs of right ventricular dysfunction-raised jugular venous pressure (65%), Kussmaull's sign (45%), hypotension (without cardiogenic shock, 40%) and right-sided third sound (25%) in the absence of clinical left ventricular failure, were noted in 65% of such patients. Eleven patients had 2 or more of the above signs. ST elevation in 2 or more right precordial leads was found in 10 of these 11 patients. A more complicated course in the hospital characterised by bradyarrhythmias, hypotension and cardiogenic shock, combined with a greater mortality was seen in such patients. We conclude that the bedside diagnosis of haemodynamically significant right ventricular infarction can be made on the basis of a combination of clinical signs and ST elevation in 2 or more right precordial leads, even in units not equipped for bedside haemodynamic monitoring, echocardiography and radionuclide studies. This should lead to a better identification and management of such patients.