Search PubMed⌕ Search

Biomedical subjects

K K Ng

Publications and source records attributed to K K Ng.

At least 73 records · Page 4Linked to original sources
PubMed1996

Structural analysis of monosaccharide recognition by rat liver mannose-binding protein.

The structural basis of carbohydrate recognition by rat liver mannose-binding protein (MBP-C) has been explored by determining the three-dimensional structure of the C-type carbohydrate-recognition domain (CRD) of MBP-C using x-ray crystallography. The structure was solved by molecular replacement using rat serum mannose-binding protein (MBP-A) as a search model and was refined to maximum Bragg spacings of 1.7 A. Despite their almost identical folds, the dimeric structures formed by the two MBP CRDs differ dramatically. Complexes of MBP-C with methyl glycosides of mannose, N-acetylglucosamine, and fucose were prepared by soaking MBP-C crystals in solutions containing these sugars. Surprisingly, the pyranose ring of mannose is rotated 180 degrees relative to the orientation observed previously in MBP-A, but the local interactions between sugar and protein are preserved. For each of the bound sugars, vicinal, equatorial hydroxyl groups equivalent to the 3- and 4-OH groups of mannose directly coordinate Ca2+ and form hydrogen bonds with residues also serving as Ca2+ ligands. Few interactions are observed between other parts of the sugar and the protein. A complex formed between free galactose and MBP-C reveals a similar mode of binding, with the anomeric hydroxyl group serving as one of the Ca2+ ligands. A second binding site for mannose has also been observed in one of two copies in the asymmetric unit at a sugar concentration of 1.3 M. These structures explain how MBPs recognize a wide range of monosaccharides and suggest how fine specificity differences between MBP-A and MBP-C may be achieved.

Amino Acid Sequence↗
PubMed1996

Acute esophageal food impaction treated by water-soluble contrast esophagography with maneuvers.

This report describes a case of acute esophageal food impaction in the lower esophagus treated by proper physical motions during esophagography using water-soluble contrast medium (WSCM). WSCM was used to avoid the complication from unexpected perforation during the examination. Relief of esophageal obstruction may be accomplished by asking the patient to jump up and down on the ground. Esophagography using WSCM combined with appropriate physical motions may be helpful in treating patients suffering from acute esophageal food impaction.

Aged↗
PubMed1996

Leg manifestation in alien hand syndrome.

A patient with left alien hand syndrome (AHS) accompanied by leg symptoms due to right anterior cerebral artery territory infarction is reported. Magnetic resonance imaging demonstrated that the responsible lesion involved the right anterior cingulate gyrus, supplementary motor area, medical prefrontal cortex and corpus callosum extending from the genu to the isthmus. The leg symptoms included: 1) motor perseveration manifesting as compulsive straight walking with difficulty stopping on command; 2) dissociation between mind and action resulting in going to unintended places with subsequent complaints of poor memory not due to spatial disorientation; 3) discrepancy between verbal and actual leg motor responses to auditory verbal suggestions; and 4) movement dissociation between the legs resulting in transient standing still or brief sticking to the ground, a situation simulating akinesia. As the legs usually perform together to coordinate movements of standing and walking, unlike the hands performing well-learned, skilled unimanual or bimanual coordinating movements, the counterpart in the leg of the alien hand sign in AHS was not manifested. Nevertheless, in the presence of AHS, the associated leg symptoms bear similar neurobehavioral features and should be dealt with on equal terms.

Cerebral Infarction↗
PubMed1995

Management and outcome of severe Guillain-Barré syndrome.

Seventy-nine patients with Guillain-Barré syndrome admitted to a neurological intensive therapy unit (ITU) between 1985 and 1992 were studied retrospectively. The mean age was 49.8 years (range 16-86) and the time between the first neurological symptom and admission to ITU was 10.2 days (0-62). Admission was precipitated by a combination of respiratory failure requiring ventilatory support (73.4%), bulbar weakness (57.0%), autonomic features (11.4%) and general medical factors (10.1%). Specific treatments included plasma exchange (65.8%), intravenous immunoglobulin (13.9%) and methylprednisolone/placebo (12.7%). Significant complications included lower respiratory tract infections (45.6%), hyponatraemia (25.3%), dysautonomia (19.0%), urinary tract infection (12.7%) and cognitive disturbances (8.9%). Four patients (5.1%) died during the acute illness. Duration of nadir correlated with duration of ventilation, duration of ITU stay and outcomes at 3 months, 6 months and 1 year. However, time to nadir, an indicator of rapidity of deterioration, did not correlate with any outcome. The low mortality in this series of acutely ill and severely disabled patients suggests that specialized intensive therapy units continue to have an important role in the management of acutely ill patients with Guillain-Barré syndrome.

Acute Disease↗
PubMed1993

Retroperitoneal Castleman's disease: report of two cases.

Castleman's disease (angiofollicular lymph node hyperplasia) is a rare benign disorder characterized by hypervascular lymphoid hyperplasia. It usually manifests as an asymptomatic, solitary mediastinal tumor, and seldom presents as an isolated retroperitoneal mass. We report two cases of histologically proven Castleman's disease occurring in the retroperitoneum. Their computed tomographic and angiographic features are presented, and the characteristics of this condition are described. Recognition of Castleman's disease in the retroperitoneal area is helpful in avoiding massive intraoperative hemorrhage and an unnecessarily extensive operation.

Adolescent↗
PubMed1992

CT findings of pediatric thoracic actinomycosis: report of four cases.

Thoracic actinomycosis is an uncommon disease, which may mimic malignancy, lymphoma or tuberculosis of the chest. In the past three years, four cases of thoracic actinomycosis have been found in children at our hospital. Their computed tomography (CT) findings included pulmonary infiltrates, a chest wall mass, pleural and pericardial effusion, mediastinum involvement and rib changes. Although the final diagnosis of Actinomyces infection depends on a bacterial culture and pathology, CT can play an important role in establishing the diagnosis and evaluating the extent of the disease.

Actinomycosis↗
PubMed1989

Hepatic actinomycosis with portal vein occlusion.

Hepatic actinomycosis with abdominal wall invasion was found by computed tomography (CT) in a 44-year-old woman. Occlusion of the main and right portal veins by the actinomycoma causing cavernous transformation was proven by angiography. Duodenobiliary reflux and communication between the biliary tree and the abscess were demonstrated by upper gastrointestinal radiography, percutaneous transhepatic cholangiogram, and CT. The imaging studies reflected the pathologic process of this disease. The unique feature of this case is that infection ascended through the duodenobiliary reflux; this should be considered one of the routes for the transmission of hepatic actinomycosis.

Actinomycosis↗
PubMed1989

Effect of acupuncture on immunoglobulins of serum, saliva and gingival sulcus fluid.

The present research is a preliminary investigation of the changes of immunoglobulins in serum, saliva and gingival sulcus fluid in response to acute and chronic acupuncture stimulation in 70 volunteers. The acute effect of acupuncture showed that 30 minutes and 24 hours after acupuncture treatment saliva IgA levels were significantly increased in those who had previous low levels of IgA, but decreased in those who had previous high levels. When acupuncture was given daily for 2 weeks, the saliva IgA level was significantly increased, about 20% higher than that of the initial value. The IgG levels in serum and gingival sulcus fluid were decreased at 30 minutes after acupuncture treatment. On the other hand, chronic acupuncture stimulation (daily for 7-10 days) significantly increased IgG levels in both serum and gingival sulcus fluid. The regulatory effect of acupuncture on the immunological function of body defense system is discussed.

Acupuncture Therapy↗
PubMed1978

Clinical and electroencephalographic data indicative of brain tumours in a seizure population.

One hundred and two patients suffering from seizures, with focal EEG signs (101 cases) and focal seizures but generalized EEG abnormalities (one case) were divided into tumour (twenty-one cases) and non-tumour (eighty-one cases) groups on the basis of contrast radiological studies. Retrospective analysis of various clinical data and EEG abnormalities, determined before the contrast radiological examinations, showed that the following were statistically significantly different between the two groups in favour of a tumoral aetiology for the seizures: age at onset of fits (greater than 20 years), presence of focal neurological signs and increased intracranial pressure, presence of focal unilateral delta waves without accompanying epileptic discharges, beta asymmetry between the cerebral hemispheres and hyperventilation-induced electrical seizures. A brain scan was a very useful screening test for the detection of a tumoral aetiology for seizures.

Age Factors↗
PubMed1977

Intraventricular chemotherapy in neonatal meningitis.

All of 16 infants with neonatal meningitis treated during a 30-month period were found to have accompanying ventriculitis at the time of the initial ventricular puncture. Fifteen of these infants were caused by gramm-negative organisms. All infants received antibiotics systemically and intraventricularly via an implanted ventriculostomy reservoir or by direct ventricular injection. Antibiotic concentrations within the ventricular fluid were monitored during chemotherapy; the complications encountered during treatment are discussed. Fifteen infants survived the infection; of these, seven infants were normal at follow-up examinations. In our experience intraventricular chemotherapy as an adjunct to systemic administration of antibiotics has greatly reduced the mortality rate in neonatal meningitis.

Ampicillin↗
PubMed1976

Interaction of angiotensin II with catecholamines in the circulation of the dog and cat.

1. The blood-bathed organ technique was employed to study the effects of angiotensin II and catecholamines on an isolated everted rat aorta bathed in the extracorporeal circulating blood of adult dogs and cats. 2. When the injections were made into the bathing blood close to the everted rat aorta, angiotensin II was half as potent as adrenaline or noradrenaline on a molar basis. 3. After intravenous injections, the vasoconstrictor potency of angiotensin was twenty times that of adrenaline or noradrenaline on the everted rat aorta. The increase in potency was due to the interaction of angiotensin II with catecholamines on the preparation. 4. Intravenous phenoxybenzamine abolished the potentiated vasoconstrictor effect of angiotensin II on the blood-bathed everted rat aorta, but it did not abolish the pressor effect of angiotensin II on the cardiovascular system of the animals. The results suggest that catecholamines released into the circulating blood by intravenous angiotensin II do not play an important role in the pressor effect of angiotensin II.

Angiotensin II↗