Search PubMed⌕ Search

Biomedical subjects

J Lam

Publications and source records attributed to J Lam.

At least 55 records · Page 3Linked to original sources
PubMed1998

Service system integration, access to services, and housing outcomes in a program for homeless persons with severe mental illness.

OBJECTIVES: This study evaluated the hypothesis that greater integration and coordination between agencies within service systems is associated with greater accessibility of services and improved client housing outcomes. METHODS: As part of the Access to Community Care and Effective Services and Supports program, data were obtained on baseline client characteristics, service use, and 3-month and 12-month outcomes from 1832 clients seen at 18 sites during the first year of program operation. Data on interorganizational relationships were obtained from structured interviews with key informants from relevant organizations in each community (n = 32-82 at each site). RESULTS: Complete follow-up data were obtained from 1340 clients (73%). After control for baseline characteristics, service system integration was associated with superior housing outcomes at 12 months, and this relationship was mediated through greater access to housing agencies. CONCLUSIONS: Service system integration is related to improved access to housing services and better housing outcomes among homeless people with mental illness.

Adult↗
PubMed1998

Defining thresholds for critical ischemia by using near-infrared spectroscopy in the adult brain.

OBJECT: Signal changes in adult extracranial tissues may have a profound effect on cerebral near-infrared spectroscopy (NIRS) measurements. During carotid surgery NIRS signals provide the opportunity to determine the relative contributions from the intra- and extracranial vascular territories, allowing for a more accurate quantification. In this study the authors applied multimodal monitoring methods to patients undergoing carotid endarterectomy and explored the hypothesis that NIRS can define thresholds for cerebral ischemia, provided extracranial NIRS signal changes are identified and removed. Relative criteria for intraoperative severe cerebral ischemia (SCI) were applied to 103 patients undergoing carotid endarterectomy. METHODS: One hundred three patients underwent carotid endarterectomy. An intraoperative fall in transcranial Doppler-detected middle cerebral artery flow velocity (%deltaFV) of greater than 60% accompanied by a sustained fall in cortical electrical activity were adopted as criteria for SCI. Ipsilateral frontal NIRS recorded the total difference in concentrations of oxyhemoglobin and deoxyhemoglobin (Total deltaHb(diff)). Interrupted time series analysis following clamping of the external carotid artery (ECA) and the internal carotid artery (ICA) allowed the different vascular components of Total deltaHb(diff) (ECA deltaHb(diff) and ICA deltaHb(diff)) to be identified. Data obtained in 76 patients were deemed suitable. A good correlation between %deltaFV and ICA deltaHb(diff) (r = 0.73, p < 0.0001) was evident. Sixteen patients (21%) fulfilled the criteria for SCI. All patients who demonstrated an ICA deltaHb(diff) of greater than 6.8 micromol/L showed SCI, and in two patients within this group nondisabling watershed infarction developed, as seen on postoperative computerized tomography scans. No patient with an ICA deltaHb(diff) less than 5 micromol/L exhibited SCI or suffered a stroke. Within the resolution of the criteria used an ICA deltaHb(diff) threshold of 6.8 micromol/L provided 100% specificity for SCI, whereas an ICA deltaHb(diff) less than 5 micromol/L was 100% sensitive for excluding SCI. When Total deltaHb(diff) was used without removing the ECA component, no thresholds for SCI were apparent. CONCLUSIONS: Carotid endarterectomy provides a stable environment for exploring NIRS-quantified thresholds for SCI in the adult head.

Adult↗
PubMed1998

[Paget disease of the bone: differential diagnosis of osteolytic lesions. Report of one case].

We report a 48 years old female with Paget's disease of the bone who consulted for leg pain. After exhaustive examination a magnetic nuclear resonance revealed a 7 mm intradural schwannoma that was resected without improvement. Four years later, with generalized, progressive bone pains, several osteolytic rib lesions were detected. A bone scintigraphy showed extensive areas of hyperfixation of Tc99 DPM. Biochemical tests were normal with exception of very high serum alkaline phosphatases. Looking for some neoplastic disease, a breast nodule was detected by mammography. Biopsy demonstrated benign disease. Finally, a rib lesion biopsy disclosed diagnosis of Paget's disease of the bone. Treatment with calcitonin, etidronate and vitamin D resulted in partial clinical improvement, reduction of abnormal isotope hyperfixation in bone scintigraphy and of serum alkaline phosphatase levels.

Biopsy↗
PubMed1998

[Pheochromocytoma and von Recklinghausen neurofibromatosis: postpartum crisis and renal artery thrombosis].

Pheochromocytoma is observed with higher frequency in patients with von Recklinghausen neurofibromatosis. We report a 36 years old female with von Recklinghausen neurofibromatosis who developed mild hypertension during the fourth month of pregnancy. A cesarean section was performed at 37 weeks of pregnancy. Thereafter, the patient presented severe hypertensive and hypotensive crises, sinus tachycardia and fever. No evidences of an infectious disease were found. Abdominal ultrasound examination showed a right adrenal mass of 7 x 5 cm. High levels of urinary cathecolamines confirmed the diagnosis of pheochromocytoma. After three weeks of prazosin therapy, the patient was operated. During the surgical procedure, an encapsulated pheochromocytoma was found and excised. A right renal atrophy and renal artery thrombosis were also found and a nephrectomy was done. Postoperative evolution was uneventful and the patient remains with normal blood pressure levels six months after the operation.

Adrenal Gland Neoplasms↗
PubMed1997

CDRH3 length is the target of selection of disease-associated IgM autoantibodies.

The experiments outlined here provide evidence for positive selection of B-1 lymphocytes secreting IgM autoantibodies in the autoimmune mev mice as a result of the reduced threshold of responsiveness to autoantigens because of PTP1C deficiency, which is targeted at the CDR3 length of the variable region of the heavy chain. In addition, characteristic differences in the size, hydrophobicity pattern, and relative local charge of the CDR3 of the heavy chain of disease-associated IgM autoantibodies from moth-eaten mice help distinguish them from physiological natural autoantibodies present in normal mice.

Animals↗
PubMed1997

Compound missense mutations in the sodium/D-glucose cotransporter result in trafficking defects.

BACKGROUND & AIMS: Defects in the Na+-dependent glucose transporter (SGLT1) are associated with the disorder glucose-galactose malabsorption, characterized by severe diarrhea. This study focused on a unique proband with glucose-galactose malabsorption who was investigated 30 years ago, and the aims of the study were to identify mutations in the SGLT1 gene and to determine the defect in sugar transport. METHODS: Mutations were identified by sequencing, and each mutant protein was then studied using a Xenopus oocyte heterologous expression system. Analysis included Western, freeze fracture, radiotracer uptake, and electrophysiological assays. RESULTS: Two heterozygous missense mutations (Cys355Ser and Leu147Arg) were identified that entirely eliminated Na+/sugar cotransport activity. Western blot analysis showed that the levels of both mutant proteins in the oocyte were comparable to wild-type SGLT1, but no complex glycosylation was detected. No SGLT1 charge movements were observed with the mutant proteins, and freeze fracture data showed that neither mutant protein reached the plasma membrane. CONCLUSIONS: The Cys355Ser and Leu147Arg mutations eliminate the Na+/sugar cotransport by blocking the transfer of SGLT1 protein from the endoplasmic reticulum to the plasma membrane. This is consistent with earlier studies on phlorizin binding to the brush border membrane of duodenal biopsy specimens from this patient.

Amino Acid Sequence↗
PubMed1997

Transesophageal echocardiography with the use of a four-millimeter probe.

Transesophageal echocardiography with the use of pediatric probes is nowadays commonly performed. However, in small children, insertion of a probe with a diameter of 7 mm may be traumatic or even impossible. We therefore tested a 17-element, 4 mm transverse plane probe in 136 pediatric patients, mainly in the operation room, catheterization laboratory, or the intensive care unit, and in three healthy adult volunteers. This probe was easy to insert, particularly during emergency situations, did not cause any complication in any patient, and provided satisfactory information despite the low number of elements. The use of a 4 mm transesophageal probe can improve the management of neonates with congenital heart disease in the operating room or the neonatal intensive care unit.

Adult↗
PubMed1997

Surgical treatment of a fistula between the right pulmonary artery and the left atrium: presentation of two cases and review of literature.

OBJECTIVE: A direct communication between the pulmonary artery and the left atrium is a rare anomaly. On the basis of two cases of our own and a literature review of 49 cases, we focus on clinical presentation, anatomy, diagnosis, and the role of surgery. METHODS: Two cases of a fistula between the right pulmonary artery and the left atrium are described in a girl of 4 years and a boy of 15 years. Both presented with unexplained cyanosis. Diagnosis was made on echocardiography and angiography. The fistula was ligated using extracorporeal circulation in the first case and not in the second case. RESULTS: The surgical results were successful with resolution of the cyanosis. CONCLUSIONS: In newborns, urgent surgery may be necessary. In other patients, early elective surgical correction should be performed to prevent complications, especially systemic and cerebral emboli, cerebral abscesses, and rupture of aneurysmal fistulas. Complete cure can be achieved by ligation and possible division or by intracardiac repair.

Adolescent↗
PubMed1997

Restricted CDR3 length of the heavy chain is characteristic of six randomly isolated disease-associated VH J558+ IgM autoantibodies in lupus prone motheaten mice.

To investigate the origin of disease-associated IgM autoantibodies (AAb), we compared the genetic and structural characteristics of IgM AAb from autoimmune prone motheaten (mev) mice with natural autoantibodies (NAAb) from normal background C57/BL6 strain. Six hybridoma-derived IgM molecules each were obtained both from mev mice, at the terminal stage of systemic autoimmune disease, and from mitogen-stimulated C57/BL6 mice. These were randomly selected for VH J558 gene expression (aberrantly expressed in mev mice). The variable regions of the IgM molecules, both from autoimmune and normal mice, were encoded by unmutated germline VH genes. Disease-associated AAb from mev mice were predominantly encoded by the J558 subfamily 186.2, whereas five J558 subfamilies were utilized in NAAb originating from normal mice. Junctional diversity as a result of N or P nucleotide insertions and D-D fusions was noted among IgMs originating from both mev (mostly B-1 lymphocytes) and C57BL/6 (mostly B-2 lymphocytes) mice. Interestingly, all six J558+ IgMs from mev mice showed a restricted CDR3 length of 10 amino acids, with similar hydrophobicity indices. Four unique V-D-J rearrangements were observed among these IgMs. None of the IgMs were polyreactive and three of the six were subsequently observed to express monospecific autoreactivity with synthetic peptides (residues 81-92 and 37-53) representing segments of the T cell CD4-accessory molecule. Three IgM antibodies had hydrophilic arginine residues in their CDR3 heavy chain region. By contrast, all six J558+ IgMs from C57/BL6 mice had variable CDR3 length, distinct VDJ rearrangements and a local negative charge in the CDR3 region. Four of these IgMs demonstrated polyreactivity with multiple conserved autoantigens and, hence, were classified as NAAb. These findings provide evidence for either positive or impaired negative selection of B-1 lymphocytes secreting disease-associated IgM AAb in mev mice. This likely results from a reduced threshold of responsiveness to autoantigens due to PTP1C deficiency, which is targeted at the CDR3 length of the variable region of the heavy chain. In addition, characteristic differences in the size and hydrophobicity pattern of the CDR3 of the heavy chain allow structural distinction between monospecific disease-associated IgM AAb and the polyreactive IgM NAAb.

Amino Acid Sequence↗
PubMed1997

Impact of representative payees on substance use by homeless persons with serious mental illness.

OBJECTIVE: Assignment of representative payees, third parties responsible for managing clients' funds, has been proposed to counter potential use of public support payments for abused substances by people with severe mental illness and substance use disorders. This study examines substance use outcomes in a sample of homeless persons with serious mental illness and substance use disorders, some of whom were assigned representative payees. METHODS: The subjects were participating in the Access to Community Care and Effective Services and Supports (ACCESS) program, a federally funded demonstration program on integrating service systems. Clients were assessed at baseline and three months after case management services were initiated. Factorial repeated-measures analysis of covariance was used to examine substance use among four client subgroups, two of which had payees and two of which did not. RESULTS: Clients in this sample (N = 1,348) showed significant improvement on all measures of substance use over the first three months in the program. Those with payees showed no greater improvement in substance abuse than those without payees, although they did have fewer days of homelessness. CONCLUSIONS: This study failed to find evidence that merely adding external money management services to existing services improves substance abuse outcomes among clients who had dual diagnoses and were homeless. Besides assigning a payee, structured behavioral interventions may be needed to produce additional clinical benefits.

Adult↗
PubMed1997

Orthopaedic ice-skating injuries in a regional hospital in Hong Kong.

Ice-skating is a popular sport in Hong Kong. Since the opening of our hospital, we have observed a special pattern of injury related to ice-skating. Individuals have had a wide range of injuries including fractures and deep tissue lacerations, many of which have needed operative intervention. Public awareness of the risks remains low. The pattern and mechanisms of injury, management modalities, and contributing factors to the injuries are discussed. Preventive measures and socioeconomic implications are also discussed.

Journal Article↗
PubMed1996

Immunomodulatory effects of IL-12 on allergic lung inflammation depend on timing of doses.

We investigated the effects of IL-12 on a murine model of allergic lung inflammation. Administration of IL-12 was timed to interfere with either allergic sensitization (early dosage) or the hypersensitivity inflammatory response in the lung (late dosage), or both (early and late dosages). Comparisons of IL-12- and PBS-treated animals within each treatment group revealed several noticeable effects of IL-12. Early dosage, and the combination of early and late dosages, strikingly decreased ragweed-specific serum IgE, tracheal ring reactivity to acetylcholine, and BAL eosinophilia following allergen challenge. In contrast, late dosage had no effect on IgE levels and only a minimal effect on tracheal ring reactivity, but had a modest effect on recruitment of eosinophils. Early dosage down-regulated IL-5 and IL-10, but did not alter IL-4 or IFN-gamma expression. Late dosage down-regulated IL-5, up-regulated IL-10 and IFN-gamma, but did not change IL-4 expression. The combination of early and late dosage down-regulated IL-4, IL-5, and IL-10 expression, but increased IFN-gamma expression and production in the BAL cells and fluids. Taken together, these results indicate that IL-12 has potent immunomodulatory effects on allergic lung inflammation that depend on the timing of IL-12 administration relative to allergic sensitization and allergen challenge.

Acetylcholine↗
PubMed1996

PROTECT (Prospective Reinfarction Outcomes in the Thrombolytic Era Cardizem CD Trial): a randomized, double-blind clinical trial of diltiazem versus atenolol in secondary prophylaxis post non-Q wave myocardial infarction.

OBJECTIVE: To describe the rationale and design of the Prospective Reinfarction Outcomes in the Thrombolytic Era Cardizem CD Trial (PROTECT). DESIGN: A multicentre, randomized, double-blind, parallel-group comparison of once daily beta-therapy versus heart rate lowering calcium channel blocker therapy, in the reduction of one-year nonfatal reinfarction and cardiovascular death (combined primary end-point) initiated 24 to 96 h post non-Q wave myocardial infarction. SETTING: One hundred and twenty hospitals across Canada. PATIENTS: Over 7500 women and men aged 21 years or older with enzyme-confirmed non-Q wave infarction and without significant left ventricular systolic dysfunction will be recruited over two years. INTERVENTIONS: Once daily beta-blocker therapy (oral atenolol, 50 to 200 mg) versus once daily calcium channel blocker therapy (oral diltiazem 120 to 360 mg) with follow-up for up to three years. CONCLUSIONS: The PROTECT will be the largest all-Canadian cardiovascular trial to date and will compare two commonly prescribed agents for secondary prophylaxis following non-Q wave infarction. The scientific question addressed by the PROTECT is of major public health importance and the results of the study will directly affect current clinical practice.

Adrenergic beta-Antagonists↗
PubMed1996

[Asymptomatic Addison disease: cause of striking reduction of insulin requirements in a patient with diabetes, Hashimoto thyroiditis and Basedow disease].

We report a 30 years old woman with sporadic poliglandular autoimmune syndrome type II, first seen with an insulin-dependent diabetes mellitus and a Graves-Basedow disease that became spontaneously hypothyroid with positive antimicrosomal antibodies. Six years later she presented with persistent vomiting and a remarkable reduction in insulin requirements. She had low basal and stimulated-cortisol levels and the diagnosis of severe adrenal failure was reached. A CT scan showed normal adrenal glands, she did not have cutaneous hyperpigmentation nor evidences of mineralocorticoid deficit. A selective autoimmune damage of the fascicular zone was assumed but a selective damage of ACTH producing pituitary cells cannot be discarded. The importance of investigating adrenal function in cases of unexplained reduction of insulin requirements is emphasized.

Addison Disease↗
PubMed1995

House dust mite allergen levels in two cities in Canada: effects of season, humidity, city and home characteristics.

The homes of 120 patients with asthma, 57 in Vancouver and 63 in Winnipeg, were studied. The characteristics of the homes were assessed by a questionnaire. Dust samples were collected and the indoor relative humidity was measured four times during the year covering all four seasons in both cities. Mite allergen levels were determined using monoclonal antibodies against Der p I and Der f I by the ELISA method. The mean levels of both mite allergens in mattress and floor samples in the homes in Vancouver and in Winnipeg were relatively low for all seasons. Mite allergen levels were found to be associated with city, season and individual home differences. They were significantly higher in Vancouver than in Winnipeg. Der p I and Der f I in mattress samples in both cities and Der f I in floor samples in Vancouver, varied by season. The indoor relative humidity level in the homes in Vancouver were also significantly higher than those in Winnipeg. There was, however, no significant association between the levels of indoor relative humidity and the levels of mite allergens after adjusting for variations in city, season and individual home. Although individual home differences were highly associated with mite allergen levels, only a few home characteristics were found to be related to mite allergen levels such as the type and the age of the home, the type of heating, the use of feather pillows and the number of occupants in the homes. Whether low levels of mite allergens are partially responsible for the relatively low prevalence of childhood asthma in Canada remains to be investigated.

Allergens↗
PubMed1995

Mite and cat allergen levels in homes and severity of asthma.

The relationships between mite and cat allergen levels in the home, skin test reactivity, and severity of asthma were explored in 120 asthmatic subjects, 57 in Vancouver and 63 in Winnipeg. Patients in the two cities were similar in age, gender distribution, and severity of asthma. Skin tests were performed using 13 common allergens, including D. pteronyssinus, D. farinae, and cat dander, as well as control subjects. Patients recorded their asthma symptoms, medication requirement, and twice daily peak expiratory flow rate for 1 yr. Dust samples were collected every 3 mo during each season of 1992 through 1993 in both cities. Mite and cat allergen levels were determined with an ELISA using monoclonal antibodies against Der p I, Der f I, and Fel d I. There was no relationship between skin test reactivity and levels of mite and cat allergens. In children with positive skin tests to either mite allergen, total mite (sum of Der p I and Der f I) allergen level was positively related to the mean daily symptom score and negatively related to the daily mean PEF (% of predicted). There was no such relationship among adult asthmatic patients with positive skin tests to either mite allergen. No relationship was found between cat allergen level and the severity of asthma.

Adult↗