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Biomedical subjects

H Lau

Publications and source records attributed to H Lau.

At least 91 records · Page 5Linked to original sources
PubMed1997

Buerger's disease in Hong Kong: a review of 89 cases.

BACKGROUND: A retrospective analysis of 103 case records from 1978 to 1996 with a provisional diagnosis of Buerger's disease was undertaken at the Department of Surgery, University of Hong Kong, Queen Mary Hospital. The aim of the study was to elucidate the clinical course and evaluate the results of surgical intervention of Buerger's disease in Hong Kong Chinese people. METHODS: Fourteen patients were subsequently excluded from the study because of inability of fulfil our diagnostic criteria. Data on clinical presentation, investigations, indications and results of surgical intervention were reviewed. Sympathectomies and arterial reconstructions were performed on 42 and four patients, respectively, for critical ischaemia or rest pain. Outcome was analysed with respect to the rate of ulcer healing, pattern of recurrence and limb loss. RESULTS: The patients were all young male heavy smokers with a mean age of 36.5 years. The majority of patients (80%) presented with ischaemic ulceration or gangrene. Vascular reconstruction was undertaken in four patients and satisfactory long-term results were obtained in three patients. Sympathectomy was able to relieve symptoms in 87% of operated patients and ischaemic ulceration healed in 2.6 (mean) +/- 1.7 (SD) months after the operation. If the patient continued to smoke, surgical intervention did not exempt the patient from a relapse or amputation. CONCLUSION: Sympathectomy provides short-term pain relief and promotes ulcer healing in patients with Buerger's disease but carries no long-term benefit. Complete abstinence from smoking is the only means of arresting the progression of the disease.

Adult↗
PubMed1997

Evaluation of preoperative hepatic function in patients with hepatocellular carcinoma undergoing hepatectomy.

BACKGROUND: Postoperative hepatic failure is the leading cause of hospital mortality following hepatectomy for hepatocellular carcinoma (HCC). This prospective study was performed to identify the best test for assessment of the adequacy of hepatic functional reserve in patients with HCC before hepatectomy. METHODS: Between April 1989 and June 1993, 127 patients with HCC underwent hepatectomy. Each patient was evaluated before operation with the indocyanine green (ICG) clearance test, the aminopyrine breath test and the amino acid clearance test. RESULTS: Fourteen patients (11 per cent) died after hepatectomy. ICG retention at 15 min showed significant differences between patients who survived or died. By discriminant analysis, the safety limit of ICG retention at 15 min for major hepatectomy was 14 per cent and the relative risk of hospital mortality was 3. CONCLUSION: The ICG clearance test, expressed as the percentage of ICG retained at 15 min, is the best discriminating preoperative test for evaluating hepatic functional reserve in patients with HCC before hepatectomy.

Adult↗
PubMed1997

Popliteal artery aneurysm: two case reports of acute lower limb ischaemia.

Two cases of thrombosed popliteal artery aneurysm causing acute ischaemia were described. This report emphasises the importance of early diagnosis and surgical intervention of this condition. We then present a brief review of clinical presentation and current management of popliteal artery aneurysm. Popliteal artery aneurysm commonly first present as acute lower limb ischaemia secondary to thrombo-embolism. Failure to recognise this limb-threatening condition can lead to delay in treatment and even limb loss. It is therefore important to increase awareness of this condition. Popliteal artery aneurysm warrants early surgical intervention, even in an asymptomatic stage because of its potential for serious complications.

Aged↗
PubMed1996

The effect of venous drainage on glucose homeostasis after experimental pancreas transplantation.

In this canine study, glucose homeostasis after clinical pancreas transplantation is complex, with the relative effect of systemic versus portal delivery of insulin remaining unresolved. Thirty-two pancreatectomized dogs received either systemic venous drainage (SVD) with bladder exocrine drainage (n = 16), or portal venous drainage (PVD) with gastric exocrine drainage (n = 16). Cyclosporine (CsA) based immunosuppression was commenced on day -7. The effect of immunosuppression was a significant increase in fasting blood glucose (FBGL) (P = 0.002), fasting insulin (P = 0.024), AUC for insulin (P = 0.009), and K values decreased (P = 0.009). FBGL and K values remained abnormal after transplantation with no significant difference seen between SVD and PVD. However, fasting insulin became significantly lower after PVD and AUC insulin fell in both groups. CsA levels fell in both groups after transplantation, mirroring the fall in AUC insulin, and implicating CsA as a major cause of peripheral resistance to insulin. In conclusion, PVD did not demonstrate a significant advantage over SVD in handling an intravenous glucose challenge. The need for pancreatectomy in large animals may make them an unsatisfactory experimental model to evaluate the glucoregulatory effects of pancreas allotransplantation.

Animals↗
PubMed1996

Experimental hyperacute rejection in pancreas allotransplants.

A model of sensitization by intraperitoneal lymph node inoculation was developed to test the hypothesis that hyperacute rejection (HAR) could occur in sensitized recipients of vascularized pancreas allografts. Ten pairs of outbred mongrel dogs that were lymphocytotoxic cross-match assay negative were inoculated with homogenized lymph nodes on either three or four occasions at fortnightly intervals before renal transplantation. A renal allograft from the same donor was used to test the HAR response and to further enhance sensitization by rejection of a vascularized organ. Pancreas transplants were performed 2 weeks later, with biopsies of the graft and blood samples taken at 0, 10, 20, and 30 min and then at 30-min intervals until the grafts were no longer viable. All renal and pancreas grafts were rejected in a classical hyperacute pattern. Within 4 min of revascularization of the pancreas, central lobular hemorrhage and vascular congestion appeared, followed by general edema. Histology demonstrated parallel changes of edema, vascular congestion, necrosis, hemorrhage, and leukocytic infiltrate, which all preceded graft infarction. A sharp decline in both arterial and venous white blood cell count and platelets occurred within 10 min of revascularization with initial sequestration and subsequent release of platelets from the graft (P=0.02). In summary, HAR of the allografted pancreas can be observed by the surgeon within minutes of revascularization, with predictable macroscopic and microscopic changes. This study supports the use of routine lymphocytotoxic cross-match tests for all recipients of pancreas transplants and implies that particular care is warranted in regraft pancreas allograft recipients.

Acute Disease↗
PubMed1995

Oral absorption of CGS-20625, an insoluble drug, in dogs and man.

Oral bioavailability of highly water-insoluble drugs is often quite limited and variable, requiring the development of improved formulations. Animal models are an essential aspect of the design and testing of such formulations designed to improve absorption in man. The present report compares the absorption of CGS-20625, an insoluble drug, in dog and man after oral administration of the drug as a powder, a solid dispersion capsule, and after gastric and duodenal administration in PEG 400 solution. CGS-20625 powder (20 mg) given orally exhibited slow, delayed absorption in both dog and man, with a Cmax of 0.26 +/- 0.07 microgram/ml at Tmax of 3 hr in dog, and 0.01 +/- 0.004 microgram/ml at 2 hr in man. Administration of CGS-20625 in PEG 400 solution improved absorption in dog and man, with a Cmax of 1.2 +/- 0.10 microgram/ml at Tmax of 0.25 hr in dog, and a Cmax of 0.10 +/- 0.04 microgram/ml at 0.5 hr in man. Tmax after administration of the hard gelatin capsule formulation was 0.9 and 1.0 hr in dog and man, with Cmax of 0.89 +/- 0.16 and 0.052 +/- 0.014 microgram/ml, respectively. Absolute bioavailability of CGS-20625 powder in the dog was 0.67 +/- 0.21, whereas the bioavailabilities of the powder and the capsule relative to the PEG 400 solution were 0.84 and 1.1, respectively, in dog, and 0.41 and 0.85 respectively, in man. No significant benefits of duodenal administration were observed. Plasma levels were approximately 10-fold greater and oral clearance was approximately 5-fold less in the dog than in man. Furthermore, pharmacokinetic data were less variable and relative bioavailability was greater in dogs than in humans. Physiological factors in the gastrointestinal tract or greater first-pass metabolism in man may account for these species differences. The relative rate and extent of CGS-20625 absorption were similar between dog and man, in the order of powder < capsule < PEG 400 solution. In addition, in vivo absorption rates in both species reflect in vitro dissolution differences between the powder and the capsule. These data strongly support the use of the dog as a model for developing improved formulations of CGS-20625. Further investigation of the dog as a model to evaluate insoluble drug absorption is warranted.

Absorption↗
PubMed1994

Gastrointestinal mucormycosis causing an acute abdomen in the immunocompromised pediatric patient--three cases.

Mucormycosis is an infection caused by a ubiquitous fungus in immunocompromised individuals. Typically, it invades blood vessels, producing thrombosis and tissue infarction. This infection spans all pediatric age groups and can lead to hollow viscus perforation and bowel obstruction. A 30-month old male with large cell anaplastic lymphoma had a bowel obstruction. During emergency laparotomy, an ileoileal intussusception was identified, which required resection and anastomosis. In the pathological specimen, fungi of the Mucorales order were found to be associated with tissue necrosis. On the eighth day of life, a premature infant had abdominal distension secondary to bowel perforation. Partial gastric resection and multiple intestinal stomas were performed. Death occurred soon after, secondary to multiorgan failure. The autopsy and surgical specimens showed widespread mucormycosis. An adolescent had meningococcemia-induced septic shock. During recovery, hemorrhagic colitis developed, which led to perforation. The subtotal colectomy specimen showed widespread mucormycosis. The laparotomy findings are typical (black necrotic tissue involving the bowel), and when seen in the immunocompromised patient, should make one suspect gastrointestinal mucormycosis. Aggressive surgical debridement of devitalized tissue augmented by intravenous antifungal medication is the mainstay of treatment.

Abdomen, Acute↗
PubMed1989

The stability of amoxycillin sodium in normal saline and glucose (5%) solutions in the liquid and frozen states.

The stability of a 1% w/v solution of amoxycillin sodium in normal saline and in glucose (5%) solutions was examined in the liquid and frozen states over the temperature range -26-60 degrees C. It was found that under all conditions amoxycillin sodium was much less stable in glucose (5%) solution. Freezing the solutions markedly reduced amoxycillin sodium stability. Maximum degradation rates in the frozen state occurred over the temperature range -7.5 degrees C to -6.5 degrees C in normal saline and at -8.9 degrees C in glucose (5%) solutions. For example, in normal saline the liquid state t90 (time for the concentration to decrease to 90% of its initial value) at 0 degree C of 252 h, was reduced to 8 h at -6.5 degrees C and increased to 14 h at -19.2 degrees C. In glucose (5%) solution comparative values of 12.5 h at 0 degree C, 2.5 h at -6.5 degrees C and 8.4 h at -19.2 degrees C were found. Amoxycillin sodium is very unstable in these solutions even at -26 degrees C. Maximum stability of the solutions examined in this study was at 0 degree C in normal saline and at -26 degrees C in glucose (5%) where the t90 value was 25.5 h.

Amoxicillin↗
PubMed1988

Neurenteric cysts--a spectrum.

This review encompasses seven patients with clinically important cystic lesions of the gastrointestinal (GI) tract, exhibiting a wide range of vertebral anomalies and connections to the neural canal. Three patients had mediastinal masses connected to lower cervical and upper thoracic anomalous vertebrae with intraspinal extensions. In addition, one of these patients had a separate, juxtapancreatic intestinal duplication cyst. One infant with colonic duplication had a lumbar vertebral anomaly and an epithelial-lined tract between the two. Another patient had a presacral cystic mass which was the site of recurrent infections and meningitis until a connection with the rectum was divided. A newborn baby had a completely split notochord syndrome with a large dorsal enteric fistula. Finally, one patient had a dorsal enteric cyst with a direct intraspinal connection. Four of the seven patients had associated significant congenital anomalies, two of whom died early in the neonatal period. The rest of the patients did well. This broad range of enteric lesions with associated vertebral and intraspinal abnormalities suggests that the clinical spectrum of neurenteric cystic lesions is much wider than is generally appreciated.

Abnormalities, Multiple↗
PubMed1988

Neonatal ovarian torsion: report of three cases and review of the literature.

Ovarian cysts are common incidental findings in term infants and, if unusually large, may result in dystocia, torsion, or rupture. Torsion and infarction of a normal ovary tend to occur in older childhood. During a 4-month period, 3 cases of neonatal ovarian torsion were observed after antenatal ultrasonography had detected fetal pelvico-abdominal cystic lesions. The three infants were explored between 4 and 16 days of age. Ovarian torsion was right-sided in all 3, and 1 ovary had been autoamputated. The resected specimens were nontense, thin-walled cysts, filled with hemorrhagic fluid, that measured between 4.5 and 8 cm in diameter. Microscopically, focal calcification and widespread necrosis precluded recognition of underlying histologic landmarks. Neonatal ovarian cysts or cystic ovaries greater than 4 cm in diameter should be excised, even if asymptomatic, because they are prone to, or have undergone, torsion.

Female↗
PubMed1988

Fetus in fetu: a fetiform teratoma.

Examination of a retroperitoneal fetus in fetu, diagnosed preoperatively, revealed previously unreported histologic findings in the vascular pedicle and membranous capsule that indicated that these structures are not "umbilical cord" or "amnion." These findings include nervous innervation of both structures and a well-defined lamina elastica interna and vaso vasorum in the artery of the vascular pedicle. Thus, strong support is provided for the theory that many examples of fetus in fetu are remarkably complex, well differentiated, highly organized teratomas. Additional arguments that favor the identity of fetus in fetu and teratoma are presented.

Abdominal Neoplasms↗