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Biomedical subjects

M Qiu

Publications and source records attributed to M Qiu.

51 records · Page 3Linked to original sources
PubMed1998

[Surgical management of closed injury of mitral valve: report of four cases].

OBJECTIVE: To show the experience in dealing with mitral valve injury caused by trauma. METHODS: Four cases of closed injury of mitral valve were treated. RESULTS: Two of the four patients presented ruptured chordae of mitral valve and were cured with annutoplasty plus repair of the chordae and mitral valve replacement respectively. One presented tearing of mitral valve leaf and pseudoaneurysm of the femoral artery, which were complicated by infective endocarditis. The patient was cured with emergency operation to repair the lesions and remove pseudoaneurysm and neoplasm in the mitral valve. Another patient, who received mitral valve replacement 8 years before, presented ruptured valve-hook of the prosthesis and died of acute heart failure without prompt operation. The diagnosis was confirmed by autopsy. CONCLUSIONS: The disease is easy to misdiagnose and once the diagnosis is established surgical intervention should be performed early. Emergency operation is necessary if acute heart failure occurs or infective endocarditis is complicated.

Adult↗
PubMed1997

Role of the Dlx homeobox genes in proximodistal patterning of the branchial arches: mutations of Dlx-1, Dlx-2, and Dlx-1 and -2 alter morphogenesis of proximal skeletal and soft tissue structures derived from the first and second arches.

The Dlx homeobox gene family is expressed in a complex pattern within the embryonic craniofacial ectoderm and ectomesenchyme. A previous study established that Dlx-2 is essential for development of proximal regions of the murine first and second branchial arches. Here we describe the craniofacial phenotype of mice with mutations in Dlx-1 and Dlx-1 and -2. The skeletal and soft tissue analyses of mice with Dlx-1 and Dlx-1 and -2 mutations provide additional evidence that the Dlx genes regulate proximodistal patterning of the branchial arches. This analysis also elucidates distinct and overlapping roles for Dlx-1 and Dlx-2 in craniofacial development. Furthermore, mice lacking both Dlx-1 and -2 have unique abnormalities, including the absence of maxillary molars. Dlx-1 and -2 are expressed in the proximal and distal first and second arches, yet only the proximal regions are abnormal. The nested expression patterns of Dlx-1, -2, -3, -5, and -6 provide evidence for a model that predicts the region-specific requirements for each gene. Finally, the Dlx-2 and Dlx-1 and -2 mutants have ectopic skull components that resemble bones and cartilages found in phylogenetically more primitive vertebrates.

Animals↗
PubMed1997

Minimum length of sequence homology required for in vivo cloning by homologous recombination in yeast.

With efficient homologous recombination in Saccharomyces cerevisiae, a rapid in vivo cloning technique has been available. Here we demonstrated that 30 bp of a homologous sequence at each end of a DNA fragment is sufficient to integrate the fragment into a linearized plasmid in yeast. To obtain a high yield of recombination transformants, however, more than 60 bp are desirable. Interestingly, we observed that 20 bp of homology at one end of a DNA fragment is sufficient for efficient recombination provided that the other end contains 80 bp of homologous sequence. Some applications, including high-throughput transferring of EST inserts to the yeast expression systems for the Human Genome Project, are discussed.

Animals↗
PubMed1997

Mutations of the homeobox genes Dlx-1 and Dlx-2 disrupt the striatal subventricular zone and differentiation of late born striatal neurons.

The striatum has a central role in many neurobiological processes, yet little is known about the molecular control of its development. Inroads to this subject have been made, due to the discovery of transcription factors, such as the Dlx genes, whose expression patterns suggest that they have a role in striatal development. We report that mice lacking both Dlx-1 and Dlx-2 have a time-dependent block in striatal differentiation. In these mutants, early born neurons migrate into a striatum-like region, which is enriched for markers of the striosome (patch) compartment. However, later born neurons accumulate within the proliferative zone. Several lines of evidence suggest that mutations in Dlx-1 and Dlx-2 produce abnormalities in the development of the striatal subventricular zone and in the differentiation of striatal matrix neurons.

Animals↗
PubMed1997

[Physiological effects of cabin temperature decrease on human].

To study effects of cabin temperature on human body, changes in rectal temperature, local skin temperature, local skin heat fluxes and skin infrared thermogram were observed in 5 male subjects dressed in different thermal insulation clothings under 20 degrees C, 15 degrees C and 10 degrees C cabin temperatures. The results showed that, average skin temperature and tip temperature obviously dropped, and skin heat fluxes increased with falling of cabin temperature, and changes of local skin infrared thermogram were significant. Subjective feeling were comfortable and cool at cabin temperature of 20 degrees C and 15 degrees C respectively. While subjective feeling was cold and there was a thermal debt of body 144 kJ/m2 at 10 degrees C which indicated that it was slightly cold but tolerable. The results may be valuable in determining the lowest tolerable limit of cabin temperature.

Acclimatization↗
PubMed1997

[Thermoregulation under simulated weightlessness].

The effect of simulated weightlessness on thermoregulation was studied in 5 subjects. The experiment consisted of 3d baseline measurements, 7d head-down bed rest and 2d recovery. Circadian rhythm was assessed by continuous measurements of rectal temperature and skin temperature with 2h intervals. Heat Stress Protein 70 (HSP70) was measured by Western-blot Dot method and the facial surface temperature distribution was measured by HR-2 infrared thermography. The results showed that rectal temperature keeps the wake-sleep variation, but the circadian rhythm changed during bed rest, and the change of rectum temperature rhythm appeared mainly in the early-days of bed rest; HSP70 and facial surface temperature increased during bed rest.

Bed Rest↗
PubMed1996

Mutation of the Emx-1 homeobox gene disrupts the corpus callosum.

Expression of the Emx-1 homeobox gene is largely restricted to the developing and mature cerebral cortex. To study its function, two lines of mice were generated using gene targeting methods that have a deletion that includes the N-terminal coding region of Emx-1. Mice homozygous for the deletion were viable and fertile and exhibited no obvious behavioral defects. However, 100% of homozygous mice lack most or all of their corpus callosum, the principle fiber tract that connects the left and right cerebral hemispheres. Heterozygotes show partial penetrance for the corpus callosum abnormality. The histology and various molecular properties of the cerebral cortex appear normal in the mutant mice.

Agenesis of Corpus Callosum↗
PubMed1996

Sequence, organization, and transcription of the Dlx-1 and Dlx-2 locus.

There are at least five murine Dlx genes that are related to the Drosophila Distal-less homeobox gene. The Dlx genes are primarily expressed in the developing forebrain, derivatives of the cranial neural crest and restricted epidermal craniofacial and limb domains. Dlx-2 is required for differentiation of subsets of cranial neural crest and forebrain cells. Previous genomic studies have shown that Dlx-1 and Dlx-2 are linked on mouse chromosome 2, near the HoxD cluster. Here we report a detailed analysis of the nucleotide sequence (approximately 14 kb), organization, and transcription of the murine Dlx-1 and Dlx-2 locus. In addition, we show that Dlx-1 makes multiple sense transcripts and at least one antisense transcript, whereas Dlx-2 makes one major transcript. The sequence of the human Dlx-2 gene is reported and is compared to that of the murine gene. Finally, sequence analysis of the deduced protein sequences reveals several candidate functional domains.

Amino Acid Sequence↗
PubMed1996

[Application of laparoscopic technique in gastrointestinal surgery].

OBJECTIVE: To evaluate the feasibility of gastrointestinal procedures guided by laparoscopy in 42 patients aged from 18 to 86 years. METHODS: We performed 10 Billroth II gastrectomies, 10 resections of gastric benign tumor, 11 repairs of duodenal perforation, 2 highly selective vagotomies, 5 resections of small bowel, 3 adhesiolyses of small bowel and 1 ileocolectomy. The operations were performed under general anesthesia with endotracheal intubation and through four portals (10mm). The omentum and mesentery were mobilized with an electrocautery and vessels controlled with either Endoclip or ELC. The reconstructions of the digestive tract were performed entirely intraabdominally with ELC. RESULTS: Except one patient receiving Billroth II gastrectomy complicated with postoperative bleeding had to be reoperated, the remaining 41 patients were successfully treated. All the 41 patients could walk and take fluids on the second postoperative day. The average length of hospitalization after operation was 7.5 days. CONCLUSIONS: Laparoscopic gastrointestinal procedures for selected cases can be carried out safely and effectively with decreased postoperative pain and rapid recovery. It may change the surgical management of some benign gastrointestinal diseases.

Adult↗
PubMed1995

Null mutation of Dlx-2 results in abnormal morphogenesis of proximal first and second branchial arch derivatives and abnormal differentiation in the forebrain.

Genetic analysis of the development and evolution of the vertebrate head is at a primitive stage. Many homeo box genes, including the Distal-less family, are potential regulators of head development. To determine the function of Dlx-2, we generated a null mutation in mice using gene targeting. In homozygous mutants, differentiation within the forebrain is abnormal and the fate of a subset of cranial neural crest cells is respecified. The latter causes abnormal morphogenesis of the skeletal elements derived from the proximal parts of the first and second branchial arches. We hypothesize that the affected skull bones from the first arch have undergone a transformation into structures similar to those found in reptiles. These results show that Dlx-2 controls development of the branchial arches and the forebrain and suggests its role in craniofacial evolution.

Animals↗
PubMed1995

[Application of laparoscopic technique in splenic surgery].

Five patients of splenic operations had been performed by laparoscopic technique. Patients' ages ranged from 19 to 47, with an average of 31. Four were males and one was female. The procedures included splenectomy 1 patient, deroofing of splenic cyst (1), and hemostasis of splenic injuries (3). The results indicated that all the procedures were successful, and the average length of postoperative stay was 6.5 days. There were no complications. The advantages of laparoscopic splenic surgery include minimal incision, less postoperative pain and rapid recovery. It should be stressed, however, that laparoscopic splenic procedures should be performed cautiously for selected indications only and by surgical endoscopists well trained.

Adult↗
PubMed1993

The small heat shock protein hsp27 is correlated with growth and drug resistance in human breast cancer cell lines.

An emerging body of evidence suggests that the heat shock proteins (hsp) may be involved in drug resistance. When hsp are induced by elevated temperatures, resistance to doxorubicin (Dox), but not to other commonly used chemotherapeutic agents, is induced in breast cancer cells. To evaluate the role of hsp27 in this phenomenon, we have transfected MDA-MB-231 breast cancer cells, which normally express low levels of hsp27, with a full-length hsp27 construct. These hsp27-overexpressing cells now display a 3-fold elevated resistance to Dox. Anchorage-dependent proliferation and anchorage-independent growth were also increased 2-4-fold in these transfectants. We have also derived a MCF-7 breast cancer cell line with amplified endogenous hsp27 which is highly resistant to Dox. When these cells are transfected with an antisense hsp27 construct, they are rendered sensitive to Dox (3-fold) with anchorage-dependent as well as anchorage-independent growth, similarly decreased. These results suggest that hsp27 specifically confers Dox resistance in human breast cancer cells and, furthermore, that hsp27 may be involved in the regulation of cell growth.

Base Sequence↗
PubMed1992

[Comparative study on activity of adenylate cyclase in normal human ovary with ovarian tumors].

It has been documented that the binding activity sites of human chorionic gonadotropin (HCG) receptor and kd in human ovarian tumors are different from those in the normal ovary. And some observations suggest that the HCG receptor depends on adenylate cyclase (AC) for its physiological functions. We studied the activity of AC in normal human ovary and ovarian tumors. Five human ovarian specimens and eighteen ovarian tumor specimens were obtained from women patients undergoing gynecological surgery. Ovaries were homogenized and sonicated. The homogenates were centrifuged at 1000 x g for 15 min. After sucrose density gradient ultracentrifugation (78000 x g, 4 h), the membrane fraction was collected from interface between 33% and 37%. The membrane protein approximately 10 micrograms, ATP 1 mmol/L, 3H-ATP 5 x 10(4) cpm, sulphydryl-ethyl alcohol 10 mmol/L, in a final volume of 200 microliters of Tris-HCl buffer (50 mmol/L), pH7.5, containing MgSO4 5 mmol/L, were incubated at 35 degrees C for 10 min. The reaction was stopped by boiling water bath for 3 min. The AC activity (U/mg): of human normal ovary, 67 +/- 8, of cystadenocarcinoma serous, 146 +/- 70; of cystadenocarcinoma mucinous, 289 +/- 83.

Adenylyl Cyclases↗