[The common morphology and clinical significance of the axillary arch].

Axillary arch is the most common type of axillary muscle fiber variation, with about 10.8% incidence in the Chinese population. Its natural forms are varied and fluid, with different starting points and terminations, and clinicians frequently lack recognition. Under commonly applicated sentinel lymph node biopsy, the axillary arch has been endowed with more clinical significance. The fabric of axillary arch will not only block lymphatic drainage in axilla and unclear anatomical level of axillary dissection, but also compress the axillary neurovascular bundle, causing upper limb venous thrombosis, lymphedema and nerve entrapment. The intumescent axillary arch may also show abnormal axillary bulge. In addition to finding axillary arch during cadaveric study and operation, several of imaging methods availably diagnose axillary arch preoperative, which can create new way for detection of axillary arch and extension of the surgical plan of sentinel lymph node biopsy. Although embryology and comparative anatomy have been used to explain the origin of the axillary arch, most of the ideas are still hypotheses and need further study.

Distinctive structure of the human GSTM3 gene-inverted orientation relative to the mu class glutathione transferase gene cluster.

The sequence and exon-intron structure of the human class mu GSTM3 glutathione transferase gene and its orientation with respect to the remainder of the human class mu GSTM gene cluster were determined. The GSTM3 gene is 2847 bp long and is thus considerably shorter than the other class mu genes in the cluster, which range in size from 5325 to 7212 bp. Outside the protein-coding region, the GSTM3 gene does not share significant sequence similarity with other class mu glutathione transferase genes. Identification of overlapping cosmid clones that span the region between GSTM5, the next nearest glutathione transferase gene, and GSTM3 showed that the two genes are about 20,000 bp apart. PCR primers developed from sequences 3'-downstream from the GSTM5 gene were used to identify clones containing the GSTM3 gene. Amplification with these primers showed that the orientation of the GSTM3 gene is 5'-GSTM5-3'-3'-GSTM3-5'. Long-range PCR reactions confirmed this orientation both in the GSTM-YAC2 YAC clone, which contains the five class mu glutathione transferase genes on chromosome 1, and in human DNA. This tail-to-tail orientation is consistent with an evolutionary model of class mu glutathione transferase divergence from a pair of tail-to-tail "M1-like" and "M3-like" class mu glutathione transferase genes that was present at the mammalian radiation to the current organization of multiple head-to-tail M1-like genes tail-to-tail with a single M3-like gene with distinct structural properties and expression patterns.

Unfolding, conformational change of active sites and inactivation of creatine kinase in SDS solutions.

It has been reported that inactivation occurs before noticeable conformational change can be detected during denaturation of creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2) and other enzymes by guanidinium chloride or urea. Therefore, Tsou suggested that enzyme active sites may display more conformational flexibility than the enzyme molecules as a whole [Tsou (1986) Trends Biochem. Sci. 11, 427-429; Tsou (1993) Science 262, 380-381]. In this study, the conformational change of the active site, the unfolding of the whole molecule and the inactivation of creatine kinase in solutions of different concentrations of SDS are compared. The results show that, at low SDS concentrations, the conformational change of the active site and inactivation of the enzyme occur to nearly the same extent. However, both of these changes occur at much lower concentrations of SDS than required to significantly unfold the enzyme molecule. The rates of conformational changes of enzyme active sites are markedly faster than those of inactivation. However, at the same SDS concentration, both the inactivation rate and the rate of the active site conformational change are much faster than that of the unfolding of the enzyme molecule as a whole. The above results provide direct evidence of the flexibility of the active site of creatine kinase.

Alkaline unfolding and salt-induced folding of aminoacylase at high pH.

The conformational changes of aminoacylase during unfolding at alkaline pH have been followed by fluorescence emission, circular dichroism (CD) and ultraviolet difference spectra. The results of comparison of inactivation and conformation show that much lower values of alkaline pH are required to bring about inactivation than significant conformational change of the enzyme molecule. At pH above 12, although the enzyme has been inactivated, the apparently fully unfolded enzyme retains some ordered secondary structure. At pH 12 by adding KCl, the relatively unfolded state of denatured enzyme changes into a compact conformational state by hydrophobic collapsing, but no new secondary structure is formed. On decreasing the pH from pH 12 to approximate neutrality, the unfolded enzyme also undertakes the similar conformational transition. It can be suggested that hydrophobic collapsed intermediate may be a general intermediate conformational state from alkaline unfolded state to native state.

Kinetics of irreversible inhibition of yeast alcohol dehydrogenase during modification by o-phthaldehyde.

The kinetic theory of the substrate reaction during irreversible inhibition of enzyme activity described previously has been applied to a study on the kinetics of the course of inactivation of yeast alcohol dehydrogenase (YADH) by o-phthaldehyde (OPTA). The microscopic constants for the reaction of the inactivators with the free enzyme and with the enzyme-substrate complexes were determined. The inactivation is a monophasic pseudo-first-order reaction with OPTA. The apparent rate constant A is independent of the OPTA concentration, indicating that the inactivation is a noncomplexing inhibition. The marked protective effect of substrates on the inactivation of YADH by OPTA has been observed. This result suggests that the modification of the enzyme by OPTA may occur at the active site.

[Panmyelosis--a report of 4 cases].

From January 1987 to December 1990, 4 cases of panmyelosis were diagnosed in our hospital, which accounted for 1.36% of all acute nonlymphocytic leukemia cases. The clinical manifestation was similar to that of acute leukemia Hb ranged from 38 to 60 g/L, WBC 5.6 x 10(9)-14.0 x 10(9)/L, blasts in peripheral blood 1%-47%. Erythroblasts and megakaryocytes were also seen in peripheral blood. Platelets were 13 x 10(9)-240 x 10(9)/L. The myelogram showed hypercellularity. Myeloblast type I+type II accounted for 26.1%-51.6% of non-erythrocytic cells. Auer body could be seen in three cases and there was a leukemic gap in each. Erythrocytic series was 34.5%-84.5% with abnormal erythroblasts. PAS staining was positive in 60%-100% erythroblasts. Megakaryocytes were 545- > 1,000/1.5 cm x 3 cm and megakaryoblasts plus promegakaryocytes were 32%-43%. There were micro-megakaryoblasts like lymphocyte in size in marrow smear and PAS staining for megakaryocytes was strongly positive. The diagnostic criteria, differential diagnosis and treatment for the disease were discussed.

[Biphenotypic acute leukemia. Clinical, morphological, cytochemical and immunophenotypic studies].

The blast cells from 2 cases of acute leukemic patients classified as M1 type by FAB criterion simultaneously expressed lymphoid markers such as SmIgG, CD19, CD20, DR, PAS in case 1 and CD9, CD10, DR, PAS in case 2. The blast cells of these two cases also expressed CD38 antigen. The data on phenotype and cytochemistry in these two cases fulfil the criteria of biphenotypic acute leukemia proposed by Dr. Gale. The problems in diagnosis, treatment and prognosis of this kind of mixed acute leukemia were discussed.