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M Lam

Publications and source records attributed to M Lam.

At least 73 records · Page 4Linked to original sources
PubMed1992

Preferential synthesis of the 78-Kd glucose-regulated protein in glucocorticoid-treated S49 mouse lymphoma cells.

To investigate the mechanism of glucocorticoid-induced lymphocytolysis, we used two-dimensional gel electrophoresis to analyze the effect of dexamethasone on the synthesis of individual proteins in S49 mouse lymphoma cells. We found that synthesis of a 78-Kd protein is preferentially maintained following dexamethasone treatment, at a time when the synthesis of most other cellular proteins is decreased. Synthesis of this protein could also be induced by tunicamycin, suggesting that it might be the 78-Kd glucose-regulated protein (GRP78). The identity of the 78-Kd protein with GRP78 was confirmed by limited chymotryptic mapping and immunoprecipitation analysis. Preferential synthesis of GRP78 in dexamethasone-treated cells was not secondary to alterations in the glycosylation of cellular proteins. Significantly, steady-state levels of GRP78 mRNA were unchanged following dexamethasone treatment. Preferential synthesis of GRP78 in glucocorticoid-treated S49 cells may reflect the unique property of GRP78 mRNA to be translated under conditions that interfere with the translation of most other cellular mRNAs. GRP78 is a highly conserved protein that is essential for cell viability. Preferential synthesis of GRP78 may be a protective response to metabolic events that interfere with normal mRNA translation in glucocorticoid-treated mouse lymphoma cells.

Animals↗
PubMed1991

A standardized technique for lower limb radiography. Practice, applications, and error analysis.

The normal standing radiograph, which provides a view of the knee only, is prone to errors of parallax and poor control of patient positioning. A standardized radiographic procedure was developed to control these sources of error. Anteroposterior and lateral views of the lower limb (hip and knee) are obtained without moving the patient from a standardized position; this includes control of ankle position and limb rotation. To correct for parallax error, radiopaque markers are positioned between the patient and the x-ray source. The locations of bone landmarks and reference markers on the radiographs are digitized, and a software package provides a display of key parameters. Error analysis of the method confirmed that most angles were sensitive to contrived positional variations, especially limb rotation and knee flexion. Load distribution between limbs was not critical. The greatest error was random. Most angles were reproducible within +/- 1.3 degrees or less at 95% confidence.

Aged↗
PubMed1991

Nutrient extraction by cold-exposed mice: a test of digestive safety margins.

We examined the size of the "safety margin," if any, by which the small intestine's daily capacities to absorb nutrients exceed prevailing daily intakes of those nutrients. This safety margin, also known as reserve capacity, is widely assumed to be enormously large. As a test, we suddenly transferred mice from an ambient temperature of 22 to 6 degrees C and measured food intake, apparent digestive efficiency, intestinal morphometrics, and intestinal brush-border uptake capacities for D-glucose and L-proline over the next 28 days. Food intake jumped 68% within the first 12 h and rose in 2 days to a new plateau level 2.5 times the previous intake. Nevertheless, apparent digestive efficiency remained unchanged, even within the first 12 h, and intestinal transit times also remained unchanged, implying the existence of at least some safety margin. Masses of the small and large intestine, liver, kidneys, and spleen nevertheless increased within 4 days by 16-20%. Glucose and proline uptakes per milligram intestine increased by approximately 5%, so that the intestine's summed uptake capacities for these solutes increased by 24-26%. The animal's intestinal adaptation expressed in these increased uptake capacities implies that safety margins at the new plateau value of food intake would otherwise have been dangerously narrow. Comparison of calculated summed uptake capacities with measured dietary intakes suggests that safety margins are approximately 220-300% in mice at 22 degrees C, only 27-50% in mice at 6 degrees C before intestinal adaptation, but 60-88% in mice at 6 degrees C after intestinal adaptation.

Animal Nutritional Physiological Phenomena↗
PubMed1990

Renal and hemodynamic effects of atrial natriuretic peptide in patients with cirrhosis.

The effects of anaritide, a 25-amino-acid synthetic analogue of ANP, were evaluated in 28 patients with cirrhosis complicated by ascites and/or edema. Each patient received two doses of the agent, as well as an infusion of placebo. Six different doses were tested ranging from 0.015-0.300 microgram/kg/min. The infusions lasted for 2 hours and were flanked by both baseline and recovery periods. There was a significant effect of placebo on urinary sodium and chloride excretion rates but no effect on urine flow rate. In response to anaritide, the urine flow rate increased at 0.03, 0.06, 0.075, and 0.100 microgram/kg/min. The sodium and chloride excretion rates increased at all doses except the highest dose. There was no definite effect of anaritide on urinary potassium, calcium, and phosphate excretion rates. There was also no significant effect on creatinine clearance. The mean arterial pressure decreased in response to the 0.060, 0.075, and 0.100 microgram/kg/min doses. In addition, five of the patients receiving the highest dose (0.300 microgram/kg/min) had decreases in their systolic pressures to 90 mm Hg or less. In conclusion, anaritide is natriuretic and diuretic in patients with cirrhosis complicated by ascites and/or edema. Its effect, however, on arterial pressure may limit its therapeutic potential in this patient population.

Atrial Natriuretic Factor↗
PubMed1989

Acquired cystic disease of the kidneys and renal cell carcinoma in chronic renal insufficiency without dialysis treatment.

We report 3 cases of acquired cystic disease of the kidneys with associated renal carcinoma in 2 of the cases. In all 3 cases, the patients had chronic renal insufficiency due to hypertension but had never required dialysis. Review of 176 reported cases of acquired cystic disease of the kidneys and renal tumors disclosed that 18 patients (including 1 previously reported by us) had never received dialysis treatment. These cases support the hypothesis that acquired cystic disease of the kidney is not restricted to patients treated with maintenance dialysis. Among the 18 patients, hypertension was the most common underlying cause of renal failure. Patients with chronic renal failure due to or associated with severe hypertension should be monitored carefully for the development of both renal cysts and tumors even though they have not started on chronic dialysis.

Aged↗
PubMed1988

Gallium 67 imaging in monitoring lymphoma response to treatment.

The value of gallium 67 (Ga) imaging in monitoring lymphoma response to treatment was assessed in 25 patients with Ga-avid tumors and compared to body computed tomography (CT), chest radiographs, and palpation of tumor infiltrated peripheral lymph nodes. Ga imaging was negative in 95% (20/21) of the patients who were clinically considered to be in remission and in whom treatment was stopped. The disease did not recur during a follow-up of 12 to 26 months in 15 patients. Six patients developed recurrence of the disease 3 to 12 months after treatment was stopped. In all six patients Ga imaging became positive again at the time of the appearance of active disease. In the group of patients in remission, CT was negative in 57% (11/19), chest x-rays in 55% (6/11) and peripheral lymph nodes were palpated in none of the patients (13/13). In four patients that did not achieve remission after treatment, Ga scans were positive. Ga imaging appears useful in monitoring lymphoma response to treatment. This is probably because Ga imaging monitors tumor cell viability, whereas body CT and chest radiographs show the tumor mass, which may consist of fibrotic or necrotic tissue.

Adolescent↗
PubMed1988

In vitro susceptibility to 10 antibiotics of methicillin-resistant (MRSA) Staphylococcus aureus in Chile.

The in vitro activity of 10 antibiotics was determined for 231 strains of methicillin resistant (MRSA) Staphylococcus aureus. Oxacillin was a very good antibiotic to determine methicillin-resistance. Its agreement with methicillin-resistance was in all the strains tested. On the contrary, the correlation with nafcillin was established only in 95% of the strains tested. Cloxacillin and flucloxacillin are not good methicillin-resistance indicators. The strains tested against macrolides, such as erythromycin, and lincosamides, such as lincomycin and clindamycin presented a susceptibility of 68, 78, and 80%, respectively. All tested strains were susceptible to vancomycin.

Anti-Bacterial Agents↗
PubMed1987

Radionuclide angiography of azygos continuation of inferior vena cava in left atrial isomerism (polysplenia syndrome).

Interruption of the inferior vena cava with azygos continuation is present in at least 65% of the patients suffering from left atrial isomerism (polysplenia syndrome). First-pass radionuclide angiography using a peripheral vein of the foot correctly diagnosed interruption of the inferior vena cava in seven patients. Four had azygos continuation to the right superior vena cava and in three it was to the left superior vena cava. In all the patients, cardiac catheterization confirmed the diagnosis. Four underwent surgical correction (or palliation), three are waiting for an operation. Radionuclide angiography is a simple outpatient procedure and useful in the clinical diagnosis of this syndrome.

Abnormalities, Multiple↗
PubMed1986

Hypomagnesemia and renal magnesium wasting in patients treated with cisplatin.

Cisplatin (cis-diamminedichloroplatinum II), a chemotherapeutic agent used against epithelial neoplasms, is known to cause hypomagnesemia and renal magnesium wasting. In order to further characterize the effect of multiple doses of this drug upon serum magnesium levels and renal magnesium handling, we prospectively studied 28 patients who received a total of 82 doses of cisplatin. All patients developed hypomagnesemia that was dose-related (r = .66, P less than .001, n = 101); the lowest serum magnesium level reached in individual patients ranged from 0.3 to 1.7 mg/dL. Renal magnesium wasting was documented in 19 patients, with urinary fractional excretion of magnesium ranging from 2.9% to 22.3% despite serum magnesium levels of greater than or equal to 1.5 mg/dL. Evidence of renal tubular injury (renal tubular epithelial cells or tubular cell casts) was detected in 47 of 47 urine sediment examinations performed two to four days after cisplatin administration. There was no clear evidence that cisplatin caused defects in renal handling of electrolytes other than magnesium; in fact, 16 of the 28 patients demonstrated avid renal reabsorption of one or more other electrolytes despite significant magnesium wasting. We conclude that cisplatin alters renal tubular handling of magnesium, resulting in significant prolonged dose-related hypomagnesemia.

Adult↗
PubMed1985

Stress fractures and bone pain: are they closely associated?

The relationship between bone pain and stress fractures diagnosed by bone scintigraphy was investigated in military recruits during active training. In three patients pain appeared in the site of abnormal uptake 7-14 days after the bone scan in a previously asymptomatic site. One hundred and twenty-four sites of stress fractures were found in 64 patients; 32 (26 per cent) were asymptomatic. In 38 patients (59 per cent) there were multiple stress fractures; 32 (33 per cent) had asymptomatic stress fractures. Fifty-three per cent of the regions with abnormal uptake in the femur were painless, compared with 17 per cent in the tibia. The necessity for imaging all bones susceptible to stress fractures, even when asymptomatic, is stressed. It is suggested that diagnosis of stress fracture should be made when typical abnormal uptake appears on scintigraphy. Bone pain in such cases may be delayed.

Adolescent↗
PubMed1985

Fractional excretion of sodium as a guide to volume depletion during recovery from acute renal failure.

Fractional excretion of filtered sodium (FENa) is typically elevated (greater than 3%) in acute tubular necrosis and decreased (less than 1%) with volume depletion. We describe a patient who developed acute tubular necrosis with a FENa of 13%. Four weeks later, he was still oliguric but had also become volume-depleted. FENa was 0.4% to 0.8%, considerably lower than FENa's measured in eight nonvolume-depleted patients in acute renal failure. Vigorous intravenous fluid therapy in this patient produced a prompt increase in urine volume and improvement in renal function. We conclude the following: (1) a marked decrease in FENa in a patient with acute tubular necrosis should suggest the development of a superimposed sodium-retaining state such as volume depletion, and (2) severe volume depletion may delay or mask recovery from acute tubular necrosis.

Acute Kidney Injury↗