[The study of skeletal mechanics of anterior crossbite evaluated with SN length]

OBJECTIVE

To study the stability of SN (anterior cranial base) length and the ability to evaluate upper lower jaws, and study the inner skeletal structure mechanism.

METHODS

Interrelated angles, SN length, maxillary and mandible length were measured, the ratios between SN and maxillary and mandible length were compared with normal standard data, the data between mixed and permanent dentition groups were compared.

RESULTS

No significant difference was found on SN length between anterior crossbite patients and normal sample. Significant difference was found between crossbite and normal data on the ratio of SN and maxillary length and mandible length. Based on evaluation of SN length, the crossbite can be divided into three types of skeletal structures including normal maxilla and longer mandible, short maxilla and normal mandible, short maxilla and longer mandible, the longer mandible is a main factor.

CONCLUSION

With the advantage of stability, SN can be used to evaluate maxilla and mandible, and decide the skeletal mechanics of crossbite individually and accurately.

Effects of vortex pinning and thermal fluctuations on the Josephson plasma resonance in Tl2Ba2CaCu2O8 and YBa2Cu3O6.5

We investigated the temperature dependence and c-axis magnetic field dependence of the Josephson plasma resonance in optimally doped Tl2Ba2CaCu2O8 thin films and underdoped YBa2Cu3O6.5 (YBCO) ortho-II single crystals using infrared spectroscopy. We obtained the c-axis penetration depths, at low temperature, in zero fields of about 20 and 7 microm, respectively. While the temperature dependencies of the resonances in the two compounds are very similar, the magnetic field dependence in YBCO is much weaker. We attribute this weak magnetic field dependence to the lower anisotropy of YBCO and interpret the observed behaviors in terms of thermal fluctuations and pinning of pancake vortices.

Polarization dependence of readout signals from periodic one-dimensional arrays of magnetic domains in magneto-optical media and crystalline-amorphous line pairs in phase-change media of optical recording

Polarization dependence of signals from periodic one-dimensional arrays of magnetic domains in magneto-optical (MO) media and crystalline domains in amorphous phase-change (PC) media has been studied by theoretical calculation and experiment. The MO signal in the small-period regime depends on the direction of incident polarization. The relative strength of the E(?) and E(?) signals changes depending on the period of the pattern, the wavelength of the light, and the numerical aperture of the objective lens. For PC media, the reflected signal has similar polarization dependence, but this dependence is weak.

Superconducting gap and strong in-plane anisotropy in untwinned YBa2Cu3O(7-delta)

With significantly improved sample quality and instrumental resolution, we clearly identify in the ( pi,0) photoemission spectra from YBa(2)Cu(3)O(6.993), in the superconducting state, the long-sought "peak-dip-hump" structure. This advance allows us to investigate the large a-b anisotropy of the in-plane electronic structure including, in particular, a 50% difference in the magnitude of the superconducting gap that scales with the energy position of the hump feature. This anisotropy, likely induced by the presence of the CuO chains, raises serious questions about attempts to quantitatively explain the YBa(2)Cu(3)O(7-delta) data from various experiments using models based on a perfectly square lattice.

Unmanipulated bone marrow transplantation from one-HLA locus mismatched siblings carries high transplant-related mortality in Chinese patients

BACKGROUND AND OBJECTIVES

We compared the outcome of bone marrow transplantation (BMT) from HLA-identical siblings (MSD) and one HLA-locus mismatched siblings (PMSD) in Chinese patients with hematologic malignancies in terms of transplant-related mortality (TRM) and disease relapse to see whether PMSD can feasibly increase the availability of donors in our population.

DESIGN AND METHODS

Medical records of patients who had received a BMT from sibling donors in the Queen Mary Hospital, Hong Kong, from March 1990 to February 2000 were reviewed (MSD 326, PMSD 20). Patients and their donors were matched for HLA-A, -B and DRB1 loci using standard serologic methods as well as polymerase chain reaction-sequence specific primers. All patients received standard anti-microbials and graft -versus host disease (GVHD) prophylaxis including cyclosporin A and a short course of methotrexate.

RESULTS

A total of 346 BMT patients were analyzed of whom 326 and 20 patients had received transplants from matched and one locus mismatched siblings, respectively. Patients receiving BMT from PMSD had a significantly higher TRM than those receiving their BMT from MSD (p=0.0016). Six patients received BMT from HLA-DR PMSD: one died 2 months post-BMT as a result of post-transplantation-related lymphoproliferative disease. Fourteen patients received BMT from HLA-A or -B PMSD: 11 of these patients died after a median of 5.6 months (range 0.6-13.7 months) due to severe GVHD (n=5), graft failure (n=2), bleeding (n=1), leukemic relapse (n=2) and thrombotic thrombocytopenic purpura (n=1). Two out of the three survivors had primary graft failure: one of these two required infusion of back-up marrow and the other had autologous regeneration. Patients in the PMSD group were at greater risk of developing severe GVHD than their MSD-recipient counterparts (p<0.001). There was no significant difference in the probability of disease relapse between patients who received BMT from MSD or PMSD.

INTERPRETATION AND CONCLUSIONS

BMT from PMSD (especially those with mismatches at HLA class I loci) carried a higher risk of TRM and morbidity than BMT from MSD in our population.

Observation of the transverse optical plasmon in SmLa0.8Sr0.2CuO4-delta

We present microwave and infrared measurements on SmLa0.8Sr0.2CuO4-delta, which are direct evidence for the existence of a transverse optical plasma mode, observed as a peak in the c-axis optical conductivity. This mode appears as a consequence of the existence of two different intrinsic Josephson couplings between the CuO2 layers, one with a Sm2O2 block layer, and the other one with a (La,Sr)2O2-delta block layer. From the frequencies and the intensities of the collective modes we determine the value of the compressibility of the two dimensional electron fluid in the copper oxygen planes.

Methylation of p15 and p16 genes in acute promyelocytic leukemia: potential diagnostic and prognostic significance

PURPOSE

To investigate the frequency of p15 and p16 gene promoter methylation in acute promyelocytic leukemia (APL), and to define its value in the detection of minimal residual disease (MRD) and treatment prognostication.

PATIENTS AND METHODS

Bone marrow DNA obtained from 26 patients with APL at diagnosis and during follow-up was studied with the methylation-specific polymerase chain reaction (MS-PCR). Serial marrow DNA was studied by MS-PCR for MRD, and disease-free and overall survival were correlated with p15 methylation status at diagnosis.

RESULTS

MS-PCR for p16 and p15 gene methylation has a maximum sensitivity of 10(-4) and 10(-5). At diagnosis, 19 patients (73.1%) exhibited p15 methylation, whereas only three patients (11.5%) exhibited p16 methylation, all of whom had concomitant p15 methylation. During follow-up, p16 methylation was acquired in two patients, one during the third hematologic relapse, and the other during transformation into therapy-related myelodysplastic syndrome. Six patients were evaluated serially with MS-PCR for p15 methylation at diagnosis and at follow-up examinations. Persistent p15 methylation preceded subsequent hematologic relapses in two patients, and conversion to negative MS-PCR for p15 methylation correlated with prolonged survival in another four patients. The 5-year disease-free survival of patients with p15 methylation was significantly inferior to that of patients without p15 methylation (15% v 62.5%; P =.02), and this remained significant in multivariate analysis.

CONCLUSION

In APL, p15 but not p16 gene methylation is frequent. It is possible that p16 methylation is acquired during clonal evolution. p15 methylation is a potential marker of MRD and might be of prognostic significance.

Arsenic trioxide- and idarubicin-induced remissions in relapsed acute promyelocytic leukaemia: clinicopathological and molecular features of a pilot study

Arsenic trioxide (As2O3) effectively induces remissions in relapsed acute promyelocytic leukaemia (APL), but the safety of its long-term administration is unknown. The anthracycline idarubicin is highly active alone or in combination chemotherapy for the treatment of APL. To minimize arsenic exposure and based on the high sensitivity of APL cells to anthracyclines, we conducted a prospective study to evaluate induction with As2O3 followed by consolidation with idarubicin in the treatment of APL in relapse. Eight patients were treated with As2O3 at a daily dose of 10 mg until remission, followed by three monthly courses of idarubicin, at 6 mg/m(2)/day for 5 days in the first course and 6 mg/m(2)/day for 2 days in the subsequent two courses. All patients achieved morphological but not molecular remission after As2O3 treatment. During As2O3 therapy, an increase in white cell count peaking at a median of 17 days occurred in all the cases. Serial flow cytometric analysis of apoptosis, with mitochondrial APO2.7 antigen expression and the sub-G1 cell fraction on DNA histogram as markers, showed induction of apoptosis of APL cells in vivo. With both qualitative and real-time quantitative polymerase chain reaction, all patients were shown to attain molecular remission after subsequent idarubicin treatment. With a median follow up of 13 months, seven of eight patients have remained in complete clinical remission, with six patients in molecular remission as well. One patient who was in third remission became PCR-positive after being transiently negative. One patient died from an intracranial extramedullary relapse after achieving marrow molecular remission. We conclude that As2O3 induction followed by idarubicin consolidation is an effective therapy for APL in relapse. This regimen avoids the possible long-term toxicities of As2O3 and mutagenicity of combination chemotherapy, a strategy that might be suitable for this potentially curable leukaemia.

[Study and drawing of standard curve of body height and weight for orthodontics]

OBJECTIVE

To study and trace the standard growth curve of body height and weight of adolescent in Shenzhen area for orthodontic diagnosis and treatment planning.

METHODS

Based on the general assessment data of 21,120 students (7-18 years) in Shenzhen, the body height and weight were measured and the standard curve of body height and weight was drawn.

RESULTS

Under 12 years, the annual increment of body height and weight was similar for both sexes. Above 12 years, the annual body height and weight increment of girls was slower than that of boys. The annual body weight increment peak was between 11-12 years for girls and 13 years for boys.

CONCLUSIONS

The standard growth curve of body height and weight plays an important role in the orthodontic diagnosis and treatment planning.

[Characterization of cefoperazone resistance gene on plasmid pFC in E. coli HX88108]

OBJECTIVE

To investigate the characterization of cefoperazone resistance gene (CPZr) on plasmid pFC in E. coli HX88108 and inquire into the mechanism of resistance to CPZ at the molecular level.

METHODS

E. coli HX88108 strain which demonstrated high-level resistance to cefoperazone (MIC, > 512 micrograms/ml) was isolated from a severely infected patient in 1988. Five plasmids coexisting in the strain were designated pFC, pFT1; pFT2, pFT3 and pFX, respectively. Four plasmids except pFX conferred CPZ resistance. Cefoperazone resistance gene (CPZr) has been cloned from plasmid pFC. beta-lactamase assays with Nitrocefin were performed.

RESULTS

The expression product of CPZr was beta-lactamase. The high level beta-lactamase enzymatic activities against cephaloridine of CPZr transformants which were detected spectrophotometrically at 260 nm wave length demonstrated high level similarities to that of pFC. MICs of 18 antibiotics were determined according to a guideline of NCCLS by broth dilution method. CPZr transformants showed moderate level resistance to ampicillin, cefazolin, cefazolin, cefamandole and CPZ (MIC, 64 micrograms/ml). Meanwhile, susceptibility testing results demonstrated that the level of resistance to CPZ of pFC transformant in this study (MIC, 64 micrograms/ml) was much lower than that in 1988 (MIC, > 512 micrograms/ml) and resistance to nofloxacin and aminoglycosides was not observed. Induction experiment and temperature-sensitive mutation of CPZ resistance were performed. CPZr colonal strains revealed the higher-level of resistance to CPZ (MIC, 512 micrograms/ml) due to antibiotic CPZ induction rather than temperature sensitive mutation.

CONCLUSION

This observation suggests that resistance to antibiotics encoded by plasmid might have been lower or lost under no antibiotic stress in a certain period, but higher under heavy stress.

Primary CD56 positive lymphomas of the gastrointestinal tract

BACKGROUND

Primary CD56 positive lymphoma of the gastrointestinal (GI) tract is rare. Genotypically, these tumors can be classified into natural killer (NK)-like T-cell lymphoma or NK cell lymphoma by the presence or absence of T-cell receptor (TCR) gene rearrangement. However, they have a considerable degree of morphologic and immunophenotypic overlap, making a definitive diagnosis difficult.

METHODS

The clinicopathologic features of three patients with primary CD56 positive lymphoma of the small and large bowel are presented. This is followed by a review of the English literature from 1966 to the present.

RESULTS

All patients had CD56 positive/CD3epsilon positive disease on paraffin section. Two patients were positive for Epstein-Barr virus-encoded early nuclear RNAs (EBER) according to in situ histochemistry results and were negative for TCR gene rearrangement, consistent with primary NK lymphoma of the GI tract. The other patient was EBER negative with rearranged TCR, consistent with NK-like T-cell lymphoma. There was no clinical or histologic evidence of enteropathy in any of the patients. The major presenting symptoms included fever, weight loss, and intestinal perforation. All patients died between 1 week and 6 months after diagnosis despite undergoing surgery and intensive chemotherapy.

CONCLUSIONS

These results, together with a literature review, suggest that primary NK cell lymphoma of the GI tract may be considered a distinct clinicopathologic entity. Both primary NK and NK-like T-cell lymphoma pursue an aggressive clinical course. EBER and TCR gene rearrangement are useful in distinguishing NK cell lymphoma from NK-like T-cell lymphoma, particularly when frozen tissue is not available for immunophenotyping.

Primary hepatic lymphoma

We report the histologic and CT imaging findings of a patient with primary Burkitt's lymphoma of the liver. She presented with a massive, painless abdominal mass. The tumor responded to chemotherapy but the patient died of neutropenic sepsis.

Giant enhancement of the thermal Hall conductivity kappa(xy) in the superconductor YBa(2)Cu(3)O(7)

In high-purity YBa(2)Cu(3)O(7), the (weak-field) thermal Hall conductivity kappa(xy) is observed to increase a thousand-fold between 90 and 30 K. The inferred quasiparticle lifetime tau increases a hundred-fold starting below 90 K, in disagreement with a recent photoemission experiment. We show that kappa(xy) exhibits a specific scaling behavior below approximately 30 K. This scaling may bear on the issue of whether Landau quantization of the quasiparticle states occurs.

Presence of potential nickel-responsive element(s) in the mouse MTH1 promoter

The murine MTH1 gene codes for MTH1, an 8-oxo-2'-deoxyguanosine 5'-triphosphate pyrophosphohydrolase (8-oxo-dGTPase) which hydrolyzes 8-oxo-dGTP, a promutagenic product of reactive oxygen species' attack on the nucleotide pool. This gene is regulated by oxidative stress. Therefore, we hypothesized that MTH1 expression can be affected by carcinogenic nickel(II), known to induce such stress. Three plasmid constructs, carrying different upstream regions of the mouse MTH1 and the chloramphenicol acetyltransferase (CAT) reporter gene, were transiently transfected into NIH 3T3 cells and the CAT protein was measured in nickel(II) acetate-treated and untreated cells. Nickel concentration-dependent increase of CAT protein level was observed for low Ni(II) concentrations, up to 400 microM Ni(II), in cells transfected with pHI103 plasmid (-5969 to +530 of the MTH1 sequence) only. Cells transfected with the pHI104 (-1331 to +530) or pHI108 (-151 to +530) plasmids did not respond to nickel(II) whatsoever. This finding demonstrated that the MTH1 sequence between -5969 and -1331 contained element(s) responsive to nickel(II) treatment. DNA sequencing revealed the presence of AP-1, NF-kappaB, and ATF-1 binding sites in both the -5969 to -1331 and -1331 to +530 regions. In contrast, two (CA)n repeats (-5642 to -5582 and -2078 to -2031), a family of B2 (-5428 to -5247) and B1 (-4559 to -4420) short interspersed repeated elements, and an (AT)n repeat (-5243 to -5230) were identified only in the -5969 to -1331 sequence. The results suggest that up-regulation of murine MTH1 expression by nickel(II) is controlled by the repeat sequences, potential candidates for nickel-responsive elements.

[Study of relativity between HBV M and HBV DNA in the cases with hepatitis B]

OBJECTIVE

Serum samples of 414 cases with hepatitis B were detected for hepatitis B markers (HBV M) and HBV DNA, in order to investigation the relationship between HBV M and HBV DNA, and its clinical significant.

METHODS

HBV M and HBV DNA were detected by ELISA and blot hybridization methods respectively.

RESULTS

HBV DNA positive rates in the groups of acute and chronic hepatitis B were higher than that in the group of liver cirrhosis (P <0.01); HBV DNA positive rates had no apparent difference between the HBsAg, HBeAg, anti-HBc positive group and the HBsAg, anti-HBs, anti-HBc positive group. Direct relativity was shown between the titer of HBsAg and/or HBeAg and the positive rate of HBV DNA.

CONCLUSIONS

HBV DNA can be treated as a sign of HBV activity; the appearance of anti-HBs can not be taken as indicator of ceasing of HBV replication; the changes in HBsAg and HBeAg titers may be used as clinical evaluation on HBV replication and index for anti-viral therapeutic effect.

Hairy cell leukemia in Hong Kong Chinese: a 12-year retrospective survey

BACKGROUND

Hairy cell leukemia (HCL) is a unique chronic B cell lymphoproliferative disease (B-LPD), with distinct clinical and pathological features, and excellent treatment response to 2-chlorodeoxyadenosine (2-CDA) and pentostatin. There have been few reports of HCL from oriental countries.

PATIENTS AND METHODS

A retrospective survey of HCL in six major hematology units in Hong Kong over a 12-year period.

RESULTS

There were 18 cases of HCL identified. Most patients presented with fever, splenomegaly and monocytopenia. Lymphadenopathy was present in three patients, and open biopsy revealed tuberculosis infection in two cases. Seven cases received interferon and 12 cases received 2-CDA. Four patients died from bronchogenic carcinoma, cerebral vascular accident, fulminant hepatitis B virus reactivation and malignant melanoma. The remaining 14 patients are in clinical remission at a median of 6 years' follow-up; two are also surviving from second malignancies (thyroid papillary carcinoma and renal cell carcinoma).

CONCLUSIONS

Parallel to the low incidence of B-LPD in Chinese, the incidence of HCL (0.035/100000 population per year) is much lower than in Western series. Other clinical features such as male dominance, clinical presentation, response to 2-CDA treatment, and association with second malignancy are similar to Western reports. However, two common complications in the Chinese population are the fulminant reactivation of hepatitis B infection and disseminated tuberculosis infection.

Consistent patterns of allelic loss in natural killer cell lymphoma

Natural killer (NK) cell lymphomas are a group of rare but highly aggressive malignancies. Clinically, they can be divided into nasal NK cell lymphomas, nonnasal NK cell lymphomas, and aggressive NK cell lymphoma/leukemia. To determine the patterns of genetic deletions in these tumors, we performed loss of heterozygosity (LOH) analysis on 15 cases (11 nasal and four nonnasal), and fluorescence in situ hybridization on three cases of aggressive lymphoma/leukemia. A panel of 41 microsatellite loci on chromosomes 6q, 11q, 13q, and 17p were investigated. LOH at chromosomes 6q and 13q was frequently detected in NK cell lymphomas, being found in 80 and 66.7% of cases, respectively. LOH at chromosomes 11q and 17p was less common, being found in 28.6 and 30.8% of cases, respectively. Most tumors showed multiple loci deletions at different chromosomal regions, but several patterns of LOH could be defined. LOH at chromosome 6q was found in 90.9% of nasal NK cell lymphomas, but only in 50% of nonnasal NK cell lymphomas. LOH at chromosome 13q was found in 63.6% of nasal NK cell lymphomas and 75% of nonnasal NK cell lymphomas. For nasal NK cell lymphomas, LOH at 13q was found in 33.3% of cases at presentation, but 100% of cases at relapse. Five tumors showed LOH in only one chromosomal region, involving 6q in three cases (two nasal and one nonnasal), and 13q in two cases (both nonnasal). For the three cases of aggressive NK cell lymphoma/leukemia studied by fluorescence in situ hybridization, DNA loss at 13q14 and 17p13 regions were demonstrated. 17p13 seemed to be more commonly involved in aggressive than nasal and nonnasal NK cell lymphomas. Our results suggested that consistent patterns of LOH could be defined in NK cell malignancies. These deleted loci may contain genes important in the initiation and progression of this lymphoma.

Genetic and clinical features of hemoglobin H disease in Chinese patients

BACKGROUND

Normally, one pair of each of the two alpha-globin genes, alpha1 and alpha2, resides on each copy of chromosome 16. In hemoglobin H disease, three of these four alpha-globin genes are affected by a deletion, a mutation, or both. We studied the alpha1-globin gene abnormalities and the clinical and hematologic features of Chinese patients with hemoglobin H disease in Hong Kong.

METHODS

We assessed the clinical features, hematologic values, serum ferritin levels, and liver function of 114 patients with hemoglobin H disease. We also performed echocardiography and magnetic resonance imaging of the liver and examined the two pairs of alpha-globin genes.

RESULTS

Hemoglobin H disease in 87 of the 114 patients (76 percent) was due to the deletion of three of the four alpha-globin genes (--/-alpha), a combination termed the deletional type of hemoglobin H. The remaining 27 patients (24 percent) had the nondeletional type of hemoglobin H disease, in which two alpha-globin genes are deleted and a third is mutated (--/alphaalphaT). All 87 patients with the deletional type of hemoglobin H were double heterozygotes in whom there was a deletion of both alpha-globin genes from one chromosome, plus a deletion of the alpha1 or alpha2 gene from the other chromosome (--/alpha- or --/-alpha). A variety of mutated alpha-globin genes was found in the patients with nondeletional type of hemoglobin H disease. Patients with the nondeletional type of the H disease had more symptoms at a younger age, more severe hemolytic anemia, and larger spleens and were more likely to require transfusions than patients with deletional hemoglobin H disease. The severity of iron overload was not related to the genotype.

CONCLUSIONS

Chinese patients in Hong Kong with the nondeletional type of hemoglobin H disease have more severe disease than those with the deletional type of the disease. Iron overload is a major cause of disability in both forms of the disease.