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Biomedical subjects

M Shi

Publications and source records attributed to M Shi.

At least 91 records · Page 5Linked to original sources
PubMed1996

Models for residual time to AIDS.

The distributions of the time from Human Immunodeficiency Virus (HIV) infection to the onset of Acquired Immune Deficiency Syndrome (AIDS) and of the residual time to AIDS diagnosis are important for modeling the growth of the AIDS epidemic and for predicting onset of the disease in an individual. Markers such as CD4 counts carry valuable information about disease progression and therefore about the two survival distributions. Building on the framework set out by Jewell and Kalbfleisch (1992), we study these two survival distributions based on stochastic models for the marker process (X(t)) and a marker-dependent hazard (h(.)). We examine various plausible CD4 marker processes and marker-dependent hazard functions for AIDS proposed in recent literature. For a random effects plus Brownian motion marker process X(t) = (a + bt + BM(t))4, where a has a normal distribution, b < 0 is an unknown parameter and BM(t) is Brownian motion, and marker-dependent hazard h(X(t)), we prove that, given CD4 cell count X(t), the residual time to AIDS distribution does not depend on the time since infection t. Using simulation and numerical integration, we find the marginal incubation period distribution, the marginal hazard and the residual time distribution for several combinations of marker processes and marker-dependent hazards. An example using data from the Multicenter AIDS Cohort Study is given. A simple regression model relating the cube root of residual time to AIDS to CD4 count is suggested.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Replacing time since human immunodeficiency virus infection by marker values in predicting residual time to acquired immunodeficiency syndrome diagnosis. Multicenter AIDS Cohort Study.

It is widely assumed that the time since human immunodeficiency virus (HIV) infection is an important indicator of HIV disease stage, yet for most infected individuals the date of infection is unknown. We consider whether marker values, such as CD4 lymphocyte number or percent and levels of serum beta2 microglobulin or serum neopterin, render time since infection unimportant for predicting the residual time to acquired immunodeficiency syndrome (AIDS) diagnosis. The Multicenter AIDS Cohort Study (MACS) contains a subsample of homosexual men whose date of HIV seroconversion is known within +/-6 months and who provide data for this analysis. From this subsample, we extract two overlapping data subsets. The first subset consists of 370 persons whose 3,723 study visits include complete data on the cellular markers CD4 lymphocyte number and percent for a period of 9 years. The second consists of 272 persons whose 1,593 visits include complete information on cellular markers and on the serological markers beta2-microglobulin and neopterin for a period of 5 1/2 years. We model the residual time to AIDS diagnosis with a regression model, in which cellular and serologic markers are the explanatory covariates (independent variables) and the residual time to AIDS is the responses variable (dependent variable). A robust estimate of the variance-covariance matrix corrects for the dependence of repeated measurements in the same individual. In the case of CD4 number and percent, the results indicate that time since infection is of none or at most little importance if the marker value is known, suggesting that time since infection can be adequately replaced by the combination of marker values. However, the serological markers alone do not eliminate the importance of the time since infection.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Antagonism of lactic acid bacteria towards Staphylococcus aureus and Escherichia coli on agar plates and in milk.

The antagonistic effect of lactic acid bacteria (LAB, including Lactobacillus acidophilus, L. bulgaricus, L. casei and Streptococcus thermophilus) on Staphylococcus aureus and Escherichia coli was evaluated on MRS agar with the deferred and cross-streaking techniques, and in milk with the plate counting method. All LAB were repressive to S aureus and E coli on the agar medium. However, their suppressive activity was significantly reduced when the agar medium was buffered to pH 7.2. In normal milk, L acidophilus strains A and B, S thermophilus and its combinations with L acidophilus A and L bulgaricus 6032 were inhibitory to S aureus, while in mastitic milk, only S thermophilus and its combinations showed inhibition. L acidophilus A and L bulgaricus 34104 were repressive to E coli growth in normal milk. S thermophilus and its combinations were inhibitory to E coli in both the normal and mastitic milk samples. These results indicate that the antagonistic activity of LAB on pathogenic bacteria varied with the type of media in which the tests were done, and that testing of in vitro antagonism in milk would be more informative than that in artificial media for in vivo tests concerning the possible roles of competitive microbiological ecology in mastitis control.

Agar↗
PubMed1996

[Lung carcinosarcoma--a report of 15 cases].

Lung carcinosarcoma is a rare pulmonary mixed malignant tumor. From November 1979 to Sept. 1992, among 4251 cases of pulmonary malignant tumor operated in our department 15 were lung carcinosarcoma (0.35%). Pneumonectomy was done in 6 patients, lobectomy in 8, thoacotomy in 1. Pathologically, squamous carcinoma with fibrosarcoma was observed in 4, squamous carcinoma with chondrosarcoma in 1, squamous carcinoma with pleomorphic sarcoma in 1, adenocarcinomma with fibrosarcoma in 7, adenocarcinoma with chondrosarcoma in 1, and small-cell carcinoma with chondrosarcoma in 1. There was no operation death. Upon follow up, the 1-, 3-, 5-, and 7-year survival rates were 66.7%, 53.3%, 42.9% and 2/7, respectively. The longest survival was 97 months. The histologica origin, the relationship between pathological findings and clinical features and the diagnosis, treatment and prognosis are discussed.

Adult↗
PubMed1996

[Computed tomographic features of malignant fibrous histiocytoma].

CT findings in 45 cases of malignant fibrous histiocytoma (MFH) were reviewed. There were 27 primary and 22 (23 episodes) cases of recurrent tumor, 4 (5 episodes) cases of recurrent tumor were initially treated in our hospital. Tumors located in craniofacial area in 16 cases, abdomen or retroperitoneum in 17, soft tissues of extremities or trunk in 12. There were 26 male and 19 female patients, with 19-82 years of age (medium, 46 years of age). The most common clinical symptom was a local mass (64.4%). On CT scan, 84% (42/50) of lesions with tumor mass > 5 cm, mostly with irregular contour, medium to markedly hyper-attenuated enhancement were revealed in 78.8% of cases and 60.6% of cases with hypo-attenuated necrotic area inside. Most of the tumors invaded adjacent organs or structures which were revealed in 75.8% of cases, such as infratemporal fossa, pterygopalatine fossa, extradural space in the craniofacial lesions; liver, psoas muscle, abdominal wall in abdominal and retroperitoneal lesions. Expansible change could be shown when paranasal sinus was invaded (8/9). The CT findings of recurrent lesions were similar to the primary ones. Enhanced CT scan may provide useful information in demonstrating the nature and extent of invasion of the tumor. Closely integrating CT and pathologic findings is important for the differential diagnosis of malignant tumors of soft tissue.

Adult↗
PubMed1996

[Kidney reinforcing and yang supporting action of cistanche deserticola Y. C. Ma before and after preparation].

The weights of seminal vesicle and prostate gland of castrated young rats were significantly increased by administration of alcoholsoluble extract from decoction of Cistanche deserticola. The weights of testes, seminal vesicle and prostate gland in mice and rats were also increased by the extract. The phagocytic function of intra-abdominal macrophage in mice was activated by decoction of Cistanche deserticola. The results showed no statistical differences between crude and prepared drugs. The maximum oral tolerance for mouse was 40 g/kg.

Animals↗
PubMed1995

Diagnosis of astrovirus by reverse transcriptase PCR in stools from patients in the UK and Saudi Arabia.

BACKGROUND: Astroviruses are becoming increasingly recognised as a cause of diarrhoea in children, and to a lesser extent, adults. Electron microscopy is the recognised standard for diagnosis but is not available in many centres. OBJECTIVES: This study set out to evaluate a RT-PCR method for the diagnosis of astrovirus in faecal specimens. STUDY DESIGN: 130 diarrhoeal stools were collected prospectively both from Saudi Arabia and Leicester, UK. The patients from each centre were age-matched. Twenty control isolates from food service staff without clinical illness were also collected. Both electron microscopy (EM) and RT-PCR (for astrovirus serotype 1) were used to diagnose astrovirus infection. RESULTS: Of 23 PCR-positive specimens, only 17 were detected by EM. The prevalence of astrovirus serotype 1 was determined by PCR as 1.5% in Saudi Arabia and 4.6% in the UK. CONCLUSION: RT-PCR is a more sensitive alternative to EM for astrovirus serotype 1.

Journal Article↗
PubMed1995

[A comparison analysis on methods of astigmatism examinations for children].

70 children 140 eyes with astigmatic refractive error were reported. The methods of examination included retinoscopy, autorefraction and keratometry. The data of eye astigmatism and keratic astigmatism measured by the methods were analyzed. It revealed that there existed a good identity among the three methods, and the relationship between eye astigmatism (EAs) and keratic astigmatism (KAs) shown by the formula EAs = 0.94 KAs - 0.13 was similar to that of previous reports. It is suggested that the keratometry be necessary as an assistant method of refraction to assure to get a reliable astigmatism result for children.

Adolescent↗
PubMed1995

[Imaging diagnosis of carcinoma of the ampulla of Vater].

Ten patients with carcinoma of the ampulla of Vater were reviewed with both ultrasonography (US), CT scans (n = 10), and hypotonic double contrast duodenum examination (n = 5). Tumor was shown by US as abrupt obstruction of distal common bile duct (n = 6), a small mass well-delineated within the dilated distal common bile duct (CBD) (n = 4). The second part of duodenum was depicted clearly in CT scan without enhancement, and a small filling defect could be revealed at the inner surface in 5 cases, as well as an abrupt obstruction of distal CBD, local mass was shown in 4 cases. Enhancement of tumor manifested as local mass and/or ductal wall thickening after iv contrast administration was shown in 3 cases. One case with local lymph node enlargement (25 mm) was revealed by US as well as CT. Non-resectability is implicated by the ill-defined contour of tumor mass and/or portal vein, superior mesenteric artery and vein, but resectability cannot be excluded by displacement and distortion of these vessels with clear delineation. Detectability of lymph node smaller than 10 mm and evaluation of T, N staging are limited by imaging examination. Local filling defect and irregularity of mucous membrane of duodenum were revealed in 4 cases by hypotonic double contrast examination.

Adult↗
PubMed1995

[Stimulating action of Carthamus tinctorius L., Angelica sinensis (Oliv.) Diels and Leonurus sibiricus L. on the uterus].

The experimental results indicate that the decoction of Chinese drugs Carthamus tinctorius, Angelica sinensis and Leonurus sibiricus has stimulating action on the uterus of mouse in vitro. The stimulating action of Carthamus tinctorius and Leomurus sibiricus has been found related to stimulating H1-receptor and alpha-adrenergic receptor of uterus, but the action of Angelica sinensis to stimulating H1-receptor of uterus only.

Animals↗
PubMed1995

[Imaging diagnosis of localized pleural mesothelioma].

Nineteen cases of localized pleural mesothelioma (benign 9, malignant 8, unclassified 2) proved by surgery and pathology were analyzed. Imaging manifestations included large mass, elliptic or spindle in shape, often lobulated and well delineated, close to pleural surface. There were calcifications or cystic changes within the mass in some cases. Of the 9 benign cases, there were pedicles of 1-8 cm in length attached to the pleural surface in 5 cases. None of the benign mesotheliomas had chest wall invasion or rib destruction. Of the 8 malignant mesothelioma 2 were peduncalated, 5 had invaded chest wall with underlying rib destruction in 4 CT has obvious advantages for the evaluation of the location and extenst of mesothelioma. Apart from invasion of the underlying rib or soft tissue. Differentiation of benign from malignant localized mesothelioma can not be made by imaging diagnosis. As malignant localized mesothelioma often recurrs after surgery, closely following-up is recommended.

Adult↗
PubMed1995

Study on nude mice inoculated with Mycobacterium leprae by multiple routes.

Immune-deficient nude mice were inoculated with nude mouse derived Mycobacterium leprae by multiple routes (intravenously, subcutaneously at the foot pads and ears). The results showed that these inoculated animals were capable of producing a great number of Mycobacterium leprae to a level 10 per gram of tissue and were detected histopathologically to have heavy lepromatous lesions. The dissemination of the infection was found particularly in sites with lower body temperature. The organisms have a partiality to striated muscles and peripheral nerves. The authors suggest that experimental leprosy in nude mice is a very useful tool for leprosy research, especially in countries without armadillos. Compared with the single-route inoculation reported previously, multiple-route inoculation is more available.

Animals↗
PubMed1994

Olfactory neurons in vitro show phenotypic orientation in epithelial spheres.

Production and differentiation of olfactory neurons occur in spherical, multi-neuronal aggregates that form in cultures where dissociated newborn rat nasal cells are plated on to CNS glial cells. We show here that neuronal cell bodies were primarily located in the peripheral layers of the spheres, and almost every neuronal sphere contained one or several non-cellular central cavities. The dendrite-like processes of the olfactory neurons, immunostained for neuron-specific tubulin or the olfactory marker protein, were aligned and directed towards the central cavities. Olfactory neurons in the intact animal show a similar relationship with the nasal lumen. Non-neuronal cells formed multiple layers centrally, bordering the cavities. This degree of phenotypic re-creation is unusual in a dissociated monolayer culture system.

Animals↗