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Biomedical subjects

D W Zhang

Publications and source records attributed to D W Zhang.

At least 37 records · Page 2Linked to original sources
PubMed1994

Billings natural family planning in Shanghai, China.

With cervical mucus, or Billings, method of family planning, a woman learns to recognize the characteristics of her cervical mucus that identify the fertile phase in her menstrual cycle. She and her partner abstain from sexual activity during a period from the first indication of mucus until four days after the mucus peak day, which includes ovulation. They also abstain during menses, because mucus can be confused with menstrual bleeding. This method of family planning is used widely, worldwide, by couples seeking a natural, reliable method of family planning. Between July 1988 and May 1990, 688 couples of child-bearing age, most of whom were parous, used the Billings method for contraception. Five hundred and fifty of these couples used the method for more than 12 months. Efficacy, continuation rates, and discontinuation rates were analyzed using life-table analysis for 10,175 woman-months of data collected. The net cumulative discontinuation rates per 100 women at 12 and 18 months were 19.85 and 34.58, respectively, resulting in continuation rates of 80.15 and 65.42. The discontinuation rates per 100 women for method-related reasons at 12 and 18 months were 1.61 and 2.84, respectively, while the discontinuation rates for unintended pregnancy were 1.02 and 1.18. During the study, 67 subjects volunteered to have vaginal smears taken from the upper part of the vaginal wall for cytologic examinations, and among them serum and urine LH levels were measured in 10 subjects and urinary estrogen and progesterone were assayed in 35 cases. These tests related other indications of the menstrual cycle to the ability of the women to judge ovulation by cervical mucus. Our research suggests that further investigation of the Billings method is warranted and that careful planning and organization are needed to disseminate the method more broadly.

Cervix Mucus↗
PubMed1994

[Surgical results of neck reconstruction in esophageal cancer located at and above the high mid-thoracic segment--a report of 414 cases].

From July 1960 through 1990, a total of 414 patients with esophageal carcinoma, including cervical 29 cases, upper thoracic 239 cases and high mid-thoracic 146 cases, were operated on with reconstruction in neck. The overall resectability rate was 90.8%. The incidences of anastomotic leakage and recurrent laryngeal nerve injury were 20.5% and 12%, respectively. The resection mortality was 7.4% (within 30 days postoperatively). The 1-, 3-, 5-, 10- and 15-years survival rates were 72.3%, 39.5%, 33.1%, 26.6% and 20.5%, respectively. The authors consider that cervical esophagogastrostomy for reconstruction of esophagus after subtotal esophagectomy is an important method and a routine operative type for the surgical management of esophageal cancer at or above high mid-thoracic segment. The main factors influencing the postoperative long-term results were p-TNM stage, lymph node metastasis and the type of resection, either palliative or curative. The preoperative irradiation might remarkably increase resectability, but hardly improved long-term survival.

Adult↗
PubMed1993

[Sleeve (bronchoplastic) lobectomy for the treatment of carcinoma of the lung: report of 135 cases].

135 cases of lung cancer were treated by sleeve (bronchoplastic) lobectomy within 24 years. 90 (66.7%) of them were of squamous cell carcinoma. Postoperative TNM classification showed 81 cases (60.0%) of stage I disease, 33 (24.4%) of stage II, 20 (14.8%) of stage III and 1 (0.7%) of stage IV. Upper lobe sleeve resection was used in 77.7% of the cases (right upper 57, left upper 48). Left upper sleeve lobectomy in 5 cases was accompanied by sleeve resection and reanastomosis of the left main pulmonary artery. One patient (0.7%) died of pulmonary thrombosis. The morbidity rate was 6.6%. Late complications included scar stricture of the anastomosis in 16 cases and recurrence at the site of anastomosis in 5. The 5- and 10-year survival rate was 56.2% and 42.9% respectively. For squamous cell carcinoma in particular, the 5-year survival was 60%. The indications and techniques of this operation are discussed in detail. Sleeve lobectomy had the advantages of preserving as much normal lung tissue as possible while keeping the principle of radical resection uncompromised. The low operative mortality and good long-term survival warrant its popularization.

Adenocarcinoma↗
PubMed1990

Group IIIA-metal hydroxides indirectly neutralize the voltage sensor of the voltage-dependent mitochondrial channel, VDAC, by interacting with a dynamic binding site.

The voltage-dependent, anion-selective mitochondrial channel, VDAC, undergoes two different conformational changes from the open to a closed state under positive and negative applied electric fields. Micromolar quantities of aluminum hydroxide and other metal trihydroxides have recently been shown to be able to inhibit this voltage-dependent closure (Dill et al. (1987) J. Membr. Biol. 99, 187-196; Zhang and Colombini (1989) Biochim. Biophys. Acta 991, 68-78). It was suggested that the inhibition results from the neutralization of the positively charged voltage sensors by the metal species. In the present study, the dynamics of the metal-binding site accompanying channel closure was investigated by adding In(OH)3 to only one side of the membrane and examining its effect on the channel's gating processes. Indium added to open channels inhibited channel closure only when the metal-containing side was on the lower potential side of the applied field. If indium was added only to the higher-potential side, the channels closed and tended to remain closed after the field was abolished. The addition of metal hydroxide after closing the channels with a negative potential on the metal side did not result in channel re-opening as would be expected for sensor neutralization. Inhibition occurred immediately, however, if the channels were first allowed to open briefly. The closed-state selectivity seemed to be very similar in the absence or presence of the metal, indicating that the metal-binding sites are not located within the pore of the channel in the closed conformation. The results are consistent with a voltage-dependent translocation across the membrane of each of two metal-binding sites on VDAC. This translocation is tightly coupled with channel opening and closing.

Anions↗
PubMed1989

Inhibition by aluminum hydroxide of the voltage-dependent closure of the mitochondrial channel, VDAC.

Micromolar quantities of aluminum have been found (Dill et al. (1987) J. Membrane Biol. 99, 187-196) to reduce the voltage dependence of the mitochondrial outer membrane channel, VDAC, from Neurospora crassa. In the present study, various metallic and organic ions were tested for possible aluminum-like effect, and only the trivalent metals exhibited a similar ability to reduce the channels voltage dependence. However, trivalency alone was not sufficient because lanthanum (III) had no effect. Quantitative analyses with three group IIIA metals (A1, Ga, and In) showed that, of the structural characteristics examined, the ability to form sufficient M(OH)3 at experimental pH was the primary property shared by all the effective metals. While providing new insight into the nature of VDAC's sensor, these results also indicate that aluminum-cell interaction may result from the presence of AI(OH)3 in solution in addition to the widely accepted AI3+-mediated interactions. While the [AI3+] is vanishingly low at neutral pH, the trihydroxide is the major form and should be considered as an important candidate for aluminum-induced cellular effects.

Aluminum Hydroxide↗
PubMed1989

Randomized clinical trial on the combination of preoperative irradiation and surgery in the treatment of esophageal carcinoma: report on 206 patients.

From June 1977 to May 1985, a prospective randomized clinical trial on pre-operative radiation for esophageal carcinoma was carried out in 206 patients. Lesions under 8 cm in length and patients younger than 65 years, at least on semi-liquid diet and not contra-indicated for surgery were randomized into a combined group (104 patients) or a surgery alone group (102 patients). Eight MV X ray units were used for the pre-operative radiation using A-P portals to deliver 4,000 cGy to the whole mediastinum and the left gastroepiploic lymphatic chain. Surgery was carried out after 2 to 4 week's rest. The immediate results of the combined group and the surgery alone group were: resection rate 93% and 85%, operative mortality 5% and 6%, intra-thoracic anastomotic leak 0% and 1%, positive pathology at the esophageal stump 0% and 2%, and lymph nodes metastasis 27% and 35% respectively. The 5-year survival rates of the combined group and the surgery alone group were 35% and 30%. We have noticed that those patients with lesions showing radiation reaction of grade III gave a 5-year survival of 50% (12/24). Because intra- and extra-thoracic lymphnode metastasis caused failures (41% and 34% of these two groups), increasing the preoperative tumor dose to 60 Gy or designing post-operative irradiation to cover the bilateral supraclavicular areas was necessary. The whole mediastinum and the left gastroepiploic lymphatics could further improve the results of surgery. Further studies are needed.

Adult↗
PubMed1988

[Surgical management of adenocarcinoma of the gastric cardia--experience in 937 patients].

A total of 937 patients with adenocarcinoma of the gastric cardia were operated on within a period of 27 years. The overall resectability rate was 74.5%, the operative mobility was 16.0% and the resection mortality was 1.7% (within 30 days postoperatively). The incidences of anastomotic leakage and pulmonary complications were 3.7% and 3.2%, respectively. These two major complications carried mortality rates of 19.2% and 4.8% and accounted for 50% of the post-operative death. The 1-, 3-, 5-, and 10- year survival rates were 66.9%, 30.0%, 19.5% and 10.3%, respectively. The authors advise regular subtotal proximal gastrectomy when the cancer is confined to the stomach only or extends distally within one third of the lesser curvature. The main factors influencing the long-term results are lymph node metastasis, carcinomatous invasion to gastric serosa and the type of resection, either palliative or curative.

Adenocarcinoma↗
PubMed1986

[Experience in the surgical treatment of 748 patients with lung cancer].

A series of 748 patients with lung cancer as treated by surgery from 1961 to 1984 is reported. Regular lobectomy was done in 445 (74%) patients, bronchoplastic lobectomy in 67 (11.2%), segmental or wedge excision in 15 (2.5%) and pneumonectomy in 74 (12.3%) in which the ratio of left to right pneumonectomy was 2.9:1. Overall resection rate was 80.4% (601/748) and resection mortality was 1.2% (7/601) (death within 30 days of operation). Overall 5 year survival rate was 42% (169/402). The 5 year survival rate was 35.3% for pneumonectomy, 54.1% for bronchoplastic lobectomy, 42.3% for regular lobectomy and 16.7% for segmental or wedge excision. In this analysis, emphasis is laid to the therapeutic validity of the different modes of surgery. Statistical data show that only when the indication of different surgical interventions are strictly adhered to and the reasonable procedures are carried out, could better results be obtained. In surgical treatment of lung cancer, it is an important principle to eradicate the tumor and its metastatic foci as thorough as possible and to conserve the respiratory function as much as possible. Regular lobectomy has now become the "standard" and first choice operation. Pneumonectomy should be reserved for the patients with absolute necessity due to the extent of the lesion, adequate cardiopulmonary function and possibility of a permanent cure. Pneumonectomy is substituted by bronchoplastic lobectomy to a certain degree, preserving more of the lung function and improving the living quality after operation and long term results. Extensive practice of this surgical modality is advised.

Adenocarcinoma↗
PubMed1985

Surgery of esophageal carcinoma.

The experience of surgical treatment in 1,874 patients with carcinoma of the esophagus seen at the Cancer Institute and Hospital of the Chinese Academy of Medical Sciences, Beijing, People's Republic of China, between 1958 and 1982, is reported. Despite the prevalence of this malignancy in this part of China, only 3% of the patients in this series had stage I disease, while 80% of the patients had either stage III or stage IV disease with extraesophageal tumor invasion and regional or distant metastases. Of the entire series there was an overall resectability rate of 83.9%, being 77.6% between 1958 and 1969 and 89.0% between 1970 and 1982. Among the 1,572 resections of the entire series, there were 66 deaths within 30 days of operation, for a resection mortality rate of 4.2%, being 4.9% between 1958 and 1969 and 3.7% between 1970 and 1982. Anastomotic leakage occurred in 67 cases of the 1,572 resections, for an incidence of 4.3%. Of the 67 cases with anastomotic leaks, 38 recovered after intensive treatment; the remaining 29 died eventually of the complication, giving a death rate of 43.3%. Pathologic studies of the 1,572 specimens showed lymph node metastasis in 46.1% of the cases. It is obvious that practically all the unresectable cases showed more extensive lymph node involvement at operation, although fixation of the tumor with severe invasion to the surrounding organs usually constituted the chief cause of unresectability. The postresection long-term survivals as calculated by the number of resections at 5, 10, and 15 years were 30.2% (390/1293), 22.4% (196/876), and 18.9% (112/594), respectively. Over one-third, or 36.8%, of the 1,874 patients in the present series were treated with a combination therapy of preoperative irradiation and surgery. The results in the group of 408 selective patients and those in the group of 83 randomized patients with midthoracic esophageal carcinomas were gratifying. In the latter group there was a resectability rate of 95.2%, a resection mortality rate of 3.8%, an incidence of intrathoracic anastomotic leakage of 0%, and a 5-year survival rate of 45.5%, as compared to 89.6%, 4.3%, 1.7%, and 25%, respectively, in the control group treated by surgery alone. From these findings it is concluded that preoperative irradiation as an adjunct can promote both the immediate and long-term results of surgery for carcinoma of the esophagus. Recent advances in the surgical treatment of carcinoma of the esophagus may change the pessimistic philosophy for this malignancy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗