Monomorphism

In the majority of patients with VT, the shape and appearance of the QRS complexes are consistent and similar, and is referred to as monomorphic VT. However, some patients experience polymorphic VT, in which the shape and appearance of the QRS complexes vary. 

Like sustained monomorphic VT, torsades de pointes may result in the absence of a pulse, or may rapidly degenerate into VF, resulting in the syndrome of sudden cardiac death. 

The typical form of proarrhythmia caused by the type Ic antiarrhythmic drugs is a rapid, sustained, monomorphic VT with a characteristic sinusoidal QRS pattern that is often resistant to resuscitation with cardioversion or overdrive pacing. Some clinicians have had success with IV lidocaine (competes for the sodium channel receptor) or sodium bicarbonate (reverses the excessive sodium channel blockade). 

Grant DM, Blum M, Beer M, et al. Monomorphic and polymorphic human arylamine N-acetyltransferases a comparison of liver isozymes and expressed products of two cloned genes. Mol Pharmacol 1991 39(2) 184-191. 

The usual situation at a molecular site (such as a sequence position) is monomorphism (only one nucleotide present in the population) or biallelism. Multiallelism is rare. This fact can be explained by population dynamics over a large number of generations. When a variant is deleteri-... 

In solution, the aminoketone 29a is in equilibrium with the heterocyclic carbinolamine 29b. The equilibrium constant varies with the substituents the various compounds of the series are, as far as is known, monomorphic, some giving crystals having the molecules in open-chain form, others giving crystals with ring-closed molecules (75). 

These MHG class I alterations have been evaluated by the analysis of the panel of tumor samples with immunohistochemistry or flow cytometry in disrupted tumor cell suspensions as well as established tumor cell lines using a series of mAbs directed against HLA class I monomorphic, HLA-A or -B locus-specific, HLA-allelic epitopes or against various APM components including TAPI, TAP2, tpn and the different LMP subunits. The results demonstrated that rates of HLA class I and APM component losses in tumor cell lines strongly varied between the different tumor types analyzed. 

Stable monomorphic VT, HR control in a fib, A/ reentrant narrow complex tachycardia 20 mg/min IV until one of these ar hythmia stopped, hypotension, QRS... 

According to recent ACC/AHA/ESC Guidelines (see Zipes et al., 2006), in patients with sutained VT, direct-current cardioversion is appropriate and most effective, and also intravenous procainamide (or ajmaline in some European countries) is recommended as a reasonable choice for initial treatment for sustained monomorphic VT in patients with acute coronary syndrome. Intravenous amiodarone or lidocaine may be reasonable chose as alternative treatment. 

Novoradovsky AG, Kidd J, Kidd K, Goldman D (1995) Apparent monomorphism of ALDH2 in seven American Indian populations. Alcohol 12 163-167... 

Studies using liver from rapid and slow acetylator phenotype rabbits in vitro showed that there were indeed small differences in acetylation (2-2.5 x) for "monomorphic" substrates such as p-aminobenzoic acid, although much smaller than for "polymorphic" substrates (10-100x). 

However, using "polymorphic" substrates with the isolated enzyme, no correlation could be found between Km and acetylator status only when "monomorphic" substrates (p-aminobenzoic acid and p-aminosalicylic acid) were used was this apparent (Table 5.15). It is notable that both these substrates are negatively charged at physiological pH. 

It should be noted that in the hamster the situation is the reverse, with p-aminobenzoic acid and p-aminosalicylic acid being polymorphically acetylated and sulfamethazine and procainamide monomorphically acetylated. 

MNNG N-methyl-N -nitro-N-nitrosoguanidine. monomer single subunit of a compound such as a protein, monomorphic with one form. 

A module M over a ring A is A-flat (or flat over A, or simply flat) if the functor N v->M AN from the category of A-modules into itself is exact. Since this functor is always right exact, the flatness means that it takes monomorphisms into monomorphisms An A-algebra B is flat over a if B is flat as an A-module... 

The further selection of an API salt for a formulation is governed by a number of factors and is crucial to the successful launch of a new medicine. Ideally this salt is monomorphic and has no hydrate or solvate forms. In some cases, the amorphous salt form may be developed to improve solubility though this is often at the expense of stability. Frequently, API salts have... 

Has the potential to provoke torsade de pointes. The rate of torsade de pointes ranged between 3.6% and 8.3% (55,56,58,59) and may be more common in women (59). Sustained episodes requiring cardioversion were seen in 1.7% to 2.4%. In addition to polymorphic VT) nonsustained monomorphic VT occurred in 3.2% to 3.6% (55,56). Therefore, continuous ECG monitoring for at least four hours after the infusion or until the QTc interval has returned to baseline. 

A significant source of false-negative scores stems from DNA samples containing impurities that inhibit PCR amplification. Such samples are readily detected by noting the relative intensities of PCR products in an RAPD pattern other than the particular polymorphism being scored (Fig. 4, lane 9). If bands that are monomorphic throughout a population are weak or absent in an individual sample, it is likely that this sample contains some inhibitory contaminant. Further purification of the sample by any of a number of standard protocols normally corrects this problem. 

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