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Biomedical subjects

A B Ng

Publications and source records attributed to A B Ng.

At least 19 recordsLinked to original sources
PubMed2001

Percutaneous manipulation of an osteoarthritic hip for femoral nailing.

An increasing number of elderly patients with femoral shaft fractures also have coexisting osteoarthritis of the hip. This proves to be difficult both in fracture reduction [1] and localisation of the point of entry into the piriform fossa. To facilitate guide wire entry in a patient with osteoarthritis of the hip, considerable adduction of the hip may be required during conventional closed antegrade femoral nailing. We describe a technique using a Steinman pin on a T-clamp to facilitate localisation of the piriform fossa.

Aged↗
PubMed2000

Bollen's jig and anterior cruciate ligament reconstruction.

We report the design of a surgical instrument that facilitates the harvest of the autologous patellar tendon in anterior cruciate ligament (ACL) reconstruction. The advantage of this jig is that it is a simple, self-centring device resulting in a reproducible and consistent autograft. Its use also minimises the potential risks of donor site morbidity such as patellar fracture and tendon rupture. We briefly describe our technique and discuss its advantages.

Anterior Cruciate Ligament↗
PubMed1994

Cutaneous malignant melanoma in teenagers.

Of 57 reviewed cases of malignant melanoma in teenagers, 51 had a minimum follow-up of 5 years. The histological and some clinical features of the 51 cases were compared for diagnostic and prognostic significance with those of 19 Spitz naevi and 10 other benign naevi using the SPSS-X computer program. The overall crude survival was 71% (males 64%, females 81%). Five patients with regional metastases survived more than 5 years, three of these more than 10 years. The main statistically significant features associated with a poor prognosis were Breslow thickness, diameter of ulcer, abnormal mitoses, pushing dermal borders and marginal (deep) mitoses. In comparison with Spitz naevi, features favouring malignancy were Breslow thickness, fine dusty cytoplasmic melanin pigment, marginal or abnormal mitoses, epithelioid intra-epidermal melanocytes below parakeratosis, dermal nests larger than junctional nests and the mitotic rate in the papillary dermis. Features favouring a benign lesion were diffuse maturation, spindle cells, spindle nuclei and Kamino bodies, especially if numerous or clustered. In comparison with the atypical benign naevi, significant features favouring malignancy were marginal or abnormal mitoses, single cell epidermal invasion below parakeratosis, large nuclei and irregular nuclei.

Adolescent↗
PubMed1988

Recovery of human fetal pancreas after one year of implantation in the diabetic patient.

Between one and six cultured human fetal pancreata were allografted into five insulin-dependent diabetic recipients and their progress monitored for a year on each occasion. To prevent rejection the tissue was cultured for 1-3 weeks before transplantation, the HLA-DR antigens of the donor tissue were matched with those of the recipient when a single pancreas was used, and four of the recipients were immunosuppressed, three because of coexisting renal grafts. Graft function was observed transiently in one of the recipients. In three others human fetal pancreas was recovered 9-14 months after transplantation, although it was being slowly rejected during this time. Beta cells were present in the graft but did not function adequately to enable immunoreactive C-peptide to be measured in peripheral blood. The issues of rejection and immaturity of the human fetal pancreas will need to be surmounted if the potential of the human fetal pancreas to normalize blood glucose levels in diabetic man is ever to be realized.

C-Peptide↗
PubMed1987

Metastatic adeno or undifferentiated carcinoma from an unknown primary site--natural history and guidelines for identification of treatable subsets.

Two hundred and eighty-six patients presenting with metastatic adenocarcinoma or undifferentiated carcinoma whose primary site was not identified by clinical history, physical examination and chest radiograph have been studied. Median survival from presentation was 22 weeks. Factors independently predicting improved survival were lymph node presentations, good performance status and body weight loss of less than 10 per cent. In 88 (31 per cent) patients the primary tumour site was subsequently identified, in 58 (20 per cent) during life. Lung cancer was the most frequently identified primary tumour, and in only 32 (11 per cent) of the patients was a 'treatable' primary tumour (i.e. germ cell, breast, ovarian, prostate, thyroid cancer or lymphoma) identified. Among the treatable primary tumours were those in eight out of 16 female patients presenting with axillary metastases who were subsequently shown to have primary breast cancer and four of 13 females presenting with ascites who were found to have primary ovarian cancer. Prostatic cancer was confirmed in five out of 13 men with raised serum acid phosphatase. Of 22 patients with elevated serum alphafoetoprotein (AFP) or beta-human chorionic gonadotrophin levels (beta HCG) 18 had some features of the 'atypical teratoma syndrome'. Of the total of 32 patients with treatable tumour types, 29 (90 per cent) were identified during life. Median survival for patients with treatable tumour types identified during life was 104 weeks, compared with 22 weeks for the group as a whole. Retrospective immunocytochemical staining of the original biopsy showed that prostatic specific antigen and antibodies to beta HCG and AFP were diagnostically useful, but a series of organ site non-specific markers of histogenesis or cellular differentiation (carcinoembryonic antigen, secretory component for IgA, peanut lectin binding, epithelial membrane antigen and keratin) showed no significant correlations with identified primary sites, responsiveness to empirical chemotherapy or survival. Metastatic undifferentiated carcinoma or adenocarcinoma from an unknown primary site represents 6.5 per cent of all referrals to the medical oncology unit, Royal Prince Alfred Hospital, Sydney. We offer guidelines for the rapid identification of the limited number of primary sites for which effective and specific forms of systemic treatment are available.

Adenocarcinoma↗
PubMed1986

Long-term survival of human fetal pancreatic tissue transplanted into an insulin-dependent diabetic patient.

The explants of two human fetal pancreases of 15 weeks gestational age were cultured for 6-7 days before being implanted in a 29-year-old insulin-dependent diabetic woman who had received a renal graft two months previously. One pancreas was placed in the flexor muscles of the forearm whilst the other was implanted in an omental pouch. To reduce the chances of rejection the tissue was cultured in vitro, the donor of the tissue placed in the forearm was DR antigen matched with the recipient and the patient remained on cyclosporin and prednisone therapy. At 3 months a mass developed in the forearm muscle at the site of transplantation, and continued to grow. Biopsy at 13 months showed a small area of original pancreas surrounded by a large collection of mature lymphocytes and fibrous tissue. A and D cells could be seen around pancreatic ducts but B cells and acinar tissue were absent. At no stage during follow-up was plasma C-peptide detected in the recipient.

Administration, Oral↗
PubMed1984

Multiple immunoperoxidase markers in benign hyperplasia and adenocarcinoma of the prostate.

A series of 60 cases of prostatic adenocarcinoma and 34 cases of benign prostatic hyperplasia were examined quantitatively after immunoperoxidase staining for prostate-specific antigen (PSA), prostate-specific acid phosphatase (PSAP), carcino-embryonic antigen (CEA), epithelial membrane antigen (EMA), alpha fetoprotein (AFP), and human chorionic gonadotrophin (HCG). The tumors were graded I to IV according to the MDAH grading system recently proposed. Fifty-nine of the 60 tumors were positive for PSA and 58 were positive for PSAP. The one PSA and PSAP negative case was CEA negative and weakly EMA positive. Grade I to III tumors stained more tumor cells and more diffusely for PSA and PSAP than grade IV tumors. There was no significant difference in the intensity or extent of staining between grade I and grade II-III tumors for PSA and PSAP. A comparison of PSA and PSAP showed that PSA stained more intensely and more extensively than PSAP. Benign prostatic tissue and low-grade prostatic tumors did not stain for CEA but three of the 20 grade IV tumors and one of the 23 grade II-III tumors did. Staining for EMA was focal and showed no relation to tumor grade. Benign and malignant lesions failed to stain for AFP and HCG.

Acid Phosphatase↗
PubMed1984

Radiologically-guided percutaneous fine needle aspiration biopsies of abdominal and osseous lesions.

The inductions, technique, complications and results of radiologically-guided percutaneous fine needle aspiration biopsy (FNAB) of abdominal and osseous sites performed over a four and a half year period at an Australian tertiary referral hospital are presented. FNAB provided a positive tissue diagnosis for malignancy in 79% of osseous and 78% of abdominal lesions with no false positive diagnoses in either series. Particular problems encountered and the methods employed to overcome them are discussed.

Abdominal Neoplasms↗
PubMed1984

Histologic differentiation of human fetal pancreatic explants transplanted into nude mice.

The transplantation of human fetal pancreas has been suggested as a means of treatment of insulin-dependent diabetes in man. We have obtained human fetal pancreata during the second trimester of pregnancy and transplanted 1-mm3 explants subcutaneously (s.c.) into both diabetic and nondiabetic nude mice, some of the tissue being cultured in vitro before implantation. These implants coalesced and grew. They were removed at intervals up to 37 wk later and showed selective differentiation of endocrine tissue that normally occurs in the fetus and neonate, with formation of bipolar, mantle, and mature islets. There was growth of this endocrine tissue with significantly more islets than in the freshly stained fetal pancreas assuming an average dimension larger than 150 micron, which is the reported mean diameter of a neonatal islet. Duct and fibrous tissue remained viable, but there was no definitive acinar tissue seen. The pancreata uncultured before implantation reached a larger size than that attained by those implants cultured before being transplanted, the difference probably being the amount of ductular and mesenchymal tissue still present. Of those glands cultured before transplantation, the longer the period of culture, the smaller the size the implants reached. Culture beyond 3 wk in vitro made it difficult to macroscopically locate the implant. These data show that, in human fetal pancreas removed from its usual environment, both selective differentiation of the endocrine component and growth of the islets can occur.

Animals↗
PubMed1984

Renal biopsy morphology in renal transplantation. A comparative study of the light-microscopic appearances of biopsies from patients treated with cyclosporin A or azathioprine prednisone and antilymphocyte globulin.

Nephrotoxicity is a major side effect of cyclosporin A (CSA) when used in renal transplantation, and the distinction between nephrotoxicity and rejection is important in patient management. One hundred twenty-five renal biopsies were examined from 56 patients entered into a controlled clinical trial aimed at comparing the efficacy of CSA therapy alone to a combination of prednisone, azathioprine, and antilymphocyte globulin (AZA). In order to define the histopathology of rejection and nephrotoxicity, all the biopsies were evaluated in a semiquantitative manner by an observer unaware of the clinical state of the patient. Comparison of the morphological appearances of 32 biopsies from patients on CSA, and 22 biopsies from AZA-treated patients performed during clinically apparent rejection episodes showed that the histological patterns of rejection were the same in both treatment groups. Comparison of the morphological features of 34 biopsies from patients receiving CSA and 13 from patients receiving AZA, performed during prolonged periods of post-transplant renal failure, who eventually recovered on continuation of original therapy, showed that there were no morphological features specific to the CSA-treated group. Five patients on CSA had oliguria which was prolonged by CSA nephrotoxicity. Thirteen biopsies from all five patients showed a diffuse interstitial fibrosis that was peculiar to this group of patients.

Antilymphocyte Serum↗
PubMed1984

Influence of cellular DNA content on disease-free survival of Stage II breast cancer patients.

Using a novel flow cytometric method to analyze paraffin-embedded archival material, cellular DNA content of the primary tumor was measured in 165 patients with Stage II breast cancer who had been entered onto a large, multicenter trial of adjuvant chemotherapy. Fifty-three (32%) of the tumors examined were diploid, and the remainder contained one or more aneuploid clones. Aneuploid tumors had more extensive axillary lymph node involvement (p less than 0.05 using chi 2 analysis), but there were no significant correlations between cellular DNA content and either menopausal or estrogen receptor status. Forty-nine of 112 (44%) patients with aneuploid tumors have relapsed, compared to 12 of 53 (23%) with diploid tumors, and relapse-free survival curves show that beyond 2 years the diploid group reaches an apparent plateau, with a projected 4-year relapse-free survival of 72%, whereas the aneuploid group shows a continuing risk of relapse with only 43% remaining relapse free at 4 years. This correlation was most pronounced in the premenopausal patients; only 5 of 36 (14%) of those with diploid tumors have relapsed compared to 23 of 63 (37%) in the aneuploid group. However, multivariate analysis using a stepwise Cox model does not thus far confirm an independent prognostic significance of cellular DNA content on disease-free survival compared to node status. The cellular DNA content of the primary tumor did not appear to influence the patients' survival following relapse. These results indicate that compared to aneuploid tumors either diploid tumors have a different natural history or they are more responsive to adjuvant chemotherapy, possibly due to a lower probability of their developing drug resistance.

Breast Neoplasms↗
PubMed1983

Surgery in patients with advanced germ cell malignancy following a clinical partial response to chemotherapy.

Twenty-one patients with metastatic germ cell tumors achieved only partial clinical tumor regression following chemotherapy, and underwent surgical biopsy or resection of the residual tumor deposits. Sixteen (76%) are at present clinically disease-free after a median 30 + months (range 17-50 months) from the time of surgery, and five (24%) died after 9-29 months. Adverse prognostic signs were the finding of persistent cancer at histopathological examination of the resected tumor masses, and the presence of elevated serum tumor markers at the time of surgery. Postchemotherapy surgery in this setting provides tissue for the prognostically important histopathological examination on which a decision regarding further chemotherapy may be based. In addition, it provides tumor bulk reduction in the cases of differentiated teratoma and persistent cancer.

Adolescent↗