Biomedical subjects
Publications and source records attributed to M L Zhang.
This study analyses the bovine SRY DNA sequence by direct sequencing procedure, followed by the designation of the PCR primers specific for bovine SRY. Using PCR amplification of bovine SRY gene, the embryo sex was determined. The results of the embryo sex identification were confirmed after the embryo transfer and pregnancies.
We describe a new point mutation in the SRY gene of a Chinese XY female with gonadal dysgenesis (Swyer syndrome). Using the double stranded DNA cycle sequencing method, a single nucleotide substitution of G-->A was identified at codon 113 of the patient's SRY gene, resulting in a conservative amino acid change from alanine (A) to threonine (T) at a residue that lies within the putative DNA binding motif. With this mutation, one MnlI recognition site is abolished and a new BsmAI site is present in the DNA sequence of the SRY gene; therefore, it is easily detected by analysis of the digestion of the amplified SRY DNA fragment on an electrophoretic agarose gel. In situ hybridisation to the XY female's chromosomes showed that her mutant SRY gene was indeed located on the short arm of her Y chromosome. The SRY mutation in the XY female reported here occurred de novo, as sequence analysis showed that it was not present in her father or other family members.
The experiment in rabbits demonstrated that the more narrow the tracheas were, the higher the frequency of respiratory sound was. The frequency of tracheal respiratory sound was about 50-100 Hz in normal rabbits. In mildly narrow frequency of respiratory sound was 50-200 Hz, in mediately narrow trachea 200-300Hz, in severely narrow trachea 400-700 Hz. 74 patients were studied. The patients with more severe inhalation injury had higher tone of respiratory sound and simultaneously showed dyspnea because their larynx-tracheas became more narrow due to edema. When high tone appeared obviously tracheostomy must be immediately performed to release obstruction of the respiratory tract. 26 of these patients underwent tracheostomy. This reliable, simple diagnosis can be used to monitor larynx-tracheal condition, and high tone of respiratory sound can be used as an indication for tracheostomy.
Female Wistar rats were trained in a Skinner-box, 30 trials per day in a dark room to establish operant defence conditioning. Training started with a light (15 s), then combined with footshock for further 8 s. When the rats learned to press the key to avoid footshock within 15 s, conditioned response was considered established. After the rats reached a conditioning rate (CR) above 80% for 5 days, cannulae were implanted into caudate-putamen. Two to three days later, Met-enkephalin (MEK) or bestatin (an aminopeptidase inhibitor) was injected bilaterally into caudate-putamen. 30 min, 2 h, 24 h and 48 h after injection, conditioning tests were conducted, with each session consisting of 30 trials. Control experiments were done when 0.9% NaCl (NS) was injected. After injection of NS, CR maintained above 80% in all 4 test sessions. MEK (60 ng/rat) or bestatin (10 micrograms/rat) significantly lowered the CR during the 30 min and 2 h test session. In the latter case, the latency (L) was also prolonged. However both CR and L returned to the control level in the 24 h and 48 h test sessions. Naloxone (2 mg/kg, i.p.) blocked the conditioning-depression effect of bestatin. No significant alteration was seen in locomotor activity after MEK or bestatin injection. The results suggest that enkephalin in caudate-putamen may be involved in the regulation of retrieval of conditioning. Bestatin mimics the effect of MEK on conditioning reflex probably by increasing production of endogenous enkephalin.
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Serum was obtained from an infertile woman (IS) inducing head-to-head agglutination of human sperm and was used to screen a human testis lambda gt11 cDNA library. A plaque producing the interacting antigen was located. The recombinant lambda gt11 was isolated and cut with EcoRI releasing a 0.7-kb cDNA. Using the 0.7-kb cDNA as a probe, a larger cDNA of 2.4 kb was isolated and its nucleotide sequence determined. It was composed of 2 427 nucleotides with an open reading frame of 1584 nucleotides encoding 528 amino acid residues. The specific antisperm antibody was isolated from IS by epitope selection, using positive plaques of E. coli Y1090. The epitope-selected antibodies interacted with a 75-kD human sperm protein and with a polypeptide in the form of a beta-galactosidase fusion protein in the recombinant lysate of E. coli Y1089, determined by immunoblot. The fusion protein was purified by affinity chromatography on an anti-beta-galactosidase-Sepharose column. It is proposed that production of anti-75-kD antibodies may be the underlying cause of the infertility.
It has been demonstrated that atrial natriuretic polypeptide (ANP), or atriopeptin, is synthesized and stored not only in the cardiac atrial myocyte but also in the central nervous system, especially in the hypothalamus. ANP may play an important role in the regulation of fluid and electrolyte balance and blood pressure in the peripheral and central nervous systems. Some of the biological actions of ANP are opposite to those of angiotensin II and arginine vasopressin in the central nervous system. However, the mechanism of action of ANP remains, in a large part, to be defined.
62 cases with inhalation injury are included in this paper. 19 patients died, constituting a mortality of 30.7%. Among the symptoms, there is a characteristic high-pitched laryngotracheal respiratory sound, which is produced by narrowing of the laryngo-tracheal tract due to edema after the injury. It can be heard in the middle of the neck with a stethoscope. It can be regarded both as a diagnostic sign of inhalation injury and an indication for tracheotomy. The pressure exerted by the eschar in the neck can be released by incising the eschar. Tracheotomy can be avoided in some patients after the releasing incisions. Other problems such as artificial ventilation, liquid resuscitation etc. are also discussed.
The immunoconjugate of anti-CCT2 monoclonal antibody linked to bleomycin A6 was adsorbed on colloidal gold particles (McAb-A6-Au). Binding and internalization of McAb-A6-Au particles in human leukemia CEM cells were examined by electron microscopy. After 60 min at 4 degrees C, McAb-A6-Au particles were bound to the surface membrane of 78% of CEM cells. Transferring to 37 degrees C for 15 min, McAb-A6-Au particles were found to be 56% inside the CEM cells and about one third of the cells contained particles in the nucleus. After 4 h at 37 degrees C the percentage of CEM cells containing McAb-A6-Au particles increased to 72%. However, only 14% of the antigenically irrelevant U937 cells contained these particles and none of them was found in the nucleus. Preincubation with unconjugated anti-CCT2 monoclonal antibody markedly blocked the McAb-A6-Au particle uptake in CEM cells. The McAb-A6-Au particles were internalized through the formation of endocytotic vesicles. In addition, some McAb-A6-Au particles were able to penetrate the plasma membrane directly into cytoplasma and notably into the nucleus. Results indicate that the immunoconjugate of monoclonal antibody linked to bleomycin A6 showed selective binding to target cells and entered the cells specifically and rapidly.
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Plasma concentrations of 6-keto-PGF1 alpha and thromboxane B2 (TXB2) were measured in 55 diabetics and 30 controls with radioimmunoassay. The correlation between diabetic microangiopathy and the ratio of TXB2 and 6-keto-PGF1 alpha was analysed. Diabetics were divided into three groups according to the change of retina and renal function. Group A, diabetics without microangiopathy; group B, diabetics with slight microangiopathy; and group C, diabetics with severe microangiopathy. The results showed that the ratio of TXB2/6-keto-PGF1 alpha was higher in B and C groups (0.997 +/- 0.31 1.10 +/- 0.25 means +/- S) than in the controls (0.72 +/- 0.17 means +/- S) (P less than 0.01). Group A patients had slightly higher level of the ratio (0.85 +/- 0.20 means +/- S) than the controls but the difference was not significant. The results suggest that the TXB2 and 6-keto-PGF1 alpha imbalance exists only in diabetics with microangiopathy and their imbalance might have more significance in the pathogenesis of diabetic microangiopathy than their individual change.
Using DNA dot-blot hybridization, restriction endonuclease gene mapping with oligonucleotide probes, restriction fragment length polymorphism linkage analysis, and hybridization, prenatal diagnosis was performed for 32 pregnancies at risk for alpha-thalassemia and for 10 pregnancies at risk for beta-thalassemia. The DNA samples were prepared from chorion villi or amniotic fluid cells.
Human phenylalanine hydroxylase (PAH) cDNA was applied as a hybridization probe to analyzing the following 8 restriction fragment length polymorphisms (RFLP) in the PAH genes of 80 normal and 28 phenylketonuric Chinese patients: BglII, 3.6 kb/1.7 kb; EcoRI, 17 kb/11 kb; EcoRV, 30 kb/25 kb; HindIII, 4.2 kb/4.0 kb; MspIa, 23 kb/19 kb; MspIb, 4.0 kb/2.2 kb; PvuIIa, 19 kb/6.0 kb and PvuIIb, 11.5 kb/9.1 kb. The frequencies of the above RFLP in normal Chinese and PKU patients are: 0.13, 0.83, 0.77, 0.81, 0.12, 0.04, 0.70, 0.10 and 0.12, 0.93, 0.89, 0.81, 0.04, 0, 0.69, 0.04, respectively. This study reveals significant differences between the frequencies of individual RFLPs when these values are compared with those of the Caucasians. Finally, the detection of RFLPs in the PAH gene in the Chinese population will permit prenatal diagnosis of PKU in China.
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Microskin grafting has proved to be an effective new procedure for the treatment of extensive burns, in which only a minimum amount of autogenous skin is needed for coverage of a large full-thickness burn wound. The technique has been improved and applied in 17 major burn patients. All patients survived. The wound covered with microskin grafts ranged from 6% to 45% TBSA, with a mean area of 24.1% TBSA. The expansion ratio of micrografts in this series reached up to 1:18, and can be greater. The wound healing was accomplished in three ways. 1) Wounds were completely resurfaced by micrografts in 24 limbs (58.5%). 2) Wounds were not totally healed with micrografts by the time the homograft was rejected, leaving only small raw areas which needed re-grafting in 12 limbs (29.3%). 3) The micrografts did not take on four limbs and one chest wall (12.2%). The improved technique, which has become more simple and feasible, is discussed in detail.
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