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Biomedical subjects

J J Lim

Publications and source records attributed to J J Lim.

At least 19 recordsLinked to original sources
PubMed2001

Foreign-body granuloma occurring in the mandible subsequent to orthognathic surgery: a case report.

We report the first case of foreign-body granuloma occurring in the mandible of a patient with a history of orthognathic surgery. A 20-year-old male patient had a hard swelling and pain in the left mandibular angle and the parotid area. Plain radiographs showed a radiolucent lesion extending from the buccal area under the left sigmoid notch of the mandible to the mandibular angle. Computed tomographs showed an expanded osteolytic mass in the same area, with destruction of most of the bone on the buccal side. A microscopic examination revealed filamentous foreign material associated with chronic inflammatory cell infiltration and an aggregation of multinucleated giant cells. Foreign-body granuloma in the mandible, although rare, should be included in the differential diagnosis in cases of postoperative masses.

Adult↗
PubMed2000

Critical incident stress management.

Recent studies have indicated implementation of the CISM Program has impacted and reduced the cost of workers' compensation claims for stress related conditions and the number of lost work days (Ott, 1997; Western Management Consultants, 1996). Occupational health professionals need to be ready to develop and implement a comprehensive critical incident stress management process in anticipation of a major event. The ability to organize, lead, or administer critical incident stress debriefings for affected employees is a key role for the occupational health professional. Familiarity with these concepts and the ability to identify a critical incident enhances value to the business by mitigating the stress and impact to the workplace. Critical Incident Stress Management Systems have the potential for decreasing stress and restoring employees to normal life function--a win/win situation for both the employees and the organization.

Absenteeism↗
PubMed1999

Phorboxazole synthetic studies. 1. Construction of a C(3-19) subtarget exploiting an extension of the Petasis-Ferrier rearrangement.

[formula: see text] In this, the first of two letters, we outline our overall strategy for the total synthesis of phorboxazoles A (1) and B (2), rare oxazole-containing macrolides possessing extraordinary antimitotic activity, and describe the assembly of a C(3-19) subtarget (-)-5 for the total synthesis of phorboxazole A. The synthesis of (-)-5 was achieved in 15 linear steps (12% overall yield), exploiting a modification of the Petasis-Ferrier rearrangement to construct the C(11-15) cis-tetrahydropyran. Dimethylaluminum chloride (Me2AlCl) proved to be the Lewis acid of choice for the Petasis-Ferrier rearrangement.

Acids↗
PubMed1999

Diagnostic imaging of pigmented villonodular synovitis of the temporomandibular joint associated with condylar expansion.

Pigmented villonodular synovitis (PVNS) is a rare lesion of the temporomandibular joint. We report a case which was initially misdiagnosed as a parotid tumor. CT revealed a well-defined mass demonstrating higher attenuation than the adjacent soft tissue with marked expansion of the mandibular condyle. MRI clearly delineated the extent of the lesion which had very low signal intensity on both T1W and T2W sequences due to the effect of hemosiderin. The usefulness of these imaging procedures in diagnosis of PVNS is discussed.

Diagnosis, Differential↗
PubMed1998

Sensory and motor dysfunction assessed by anorectal manometry in uterine cervical carcinoma patients with radiation-induced late rectal complication.

PURPOSE: To investigate the effects of radiation on anorectal function in patients with carcinoma of the uterine cervix. METHODS AND MATERIALS: Anorectal manometry was carried out on 24 patients (complication group) with late radiation proctitis. All of the manometric data from these patients were compared with those from 24 age-matched female volunteers (control group), in whom radiation treatment had not yet been performed. RESULTS: Regardless of the severity of proctitis symptoms, 25% of patients demonstrated all their manometric data within the normal range, but 75% of patients exhibited one or more abnormal manometric parameters for sensory or motor functions. Six patients (25%) had an isolated sensory dysfunction, eight patients (33.3%) had an isolated motor dysfunction, and four patients (16.7%) had combined disturbances of both sensory and motor functions. The maximum tolerable volume, the minimal threshold volume, and the urgent volume in the complication group were significantly reduced compared with those in the control group. The mean squeeze pressure in the complication group was significantly reduced, whereas the mean resting pressure and anal sphincter length were unchanged. CONCLUSIONS: Physiologic changes of the anorectum in patients with late radiation proctitis seem to be caused by a variety of sensory and/or motor dysfunctions in which many different mechanisms are working together. The reduced rectal reservoir capacity and impaired sensory functions were crucial factors for functional disorder in such patients. In addition, radiation damage to the external anal sphincter muscle was considered to be an important cause of motor dysfunction.

Adult↗
PubMed1998

Rapid response: care of burn victims.

1. The occupational health nurse must understand the prehospital principles for treatment of burn victims. This understanding promotes appropriate burn management which can impact mortality and morbidity. 2. The most important concept in emergency management of burn victims is scene safety, the nurse's safety, and ultimately, the victim's safety. 3. All burn victims need to be managed as trauma victims with a primary and secondary survey to rapidly determine life threatening problems and whether other injuries are present. 4. Familiarity with the structures and functions of the skin is imperative to understand the pathophysiology and consequences of burn injuries.

Acute Disease↗
PubMed1997

Assessment of the trauma victim in an occupational setting.

1. It is important for the occupational health nurse to be aware of and understand the mechanism of injury and forces involved in a trauma event. This understanding provides insight into the potential injuries that may be present even if the victim appears unhurt. 2. The primary survey is designed to rapidly determine life threatening problems and provide immediate interventions. 3. The secondary survey is a more detailed, head to toe assessment of the victim to determine if other injuries are present. This part of the examination helps determine more subtle findings.

Emergencies↗
PubMed1988

An 11-kDa form of human immunodeficiency virus protease expressed in Escherichia coli is sufficient for enzymatic activity.

In order to define the protease domain of human immunodeficiency virus 1, various regions of the pol open reading frame were cloned and expressed in Escherichia coli. Antiserum directed against the conserved retroviral protease active site was used to identify pol precursor and processed species containing the presumed protease domain. The smallest product that accumulates is about 11 kDa as measured by NaDodSO4/PAGE. This size agrees with that predicted from the presence in this region of two Phe-Pro sequences, which is one of the cleavage sites recognized by HIV protease. DNA encoding only the predicted 11-kDa protein was cloned, bypassing the need for autoprocessing, and the protein was expressed to a high level in E. coli. This form is active as demonstrated by its ability to specifically cleave protease-deficient pol protein in vivo in E. coli. Extracts of E. coli containing the 11-kDa protease also process human immunodeficiency virus gag substrates in vitro. These results demonstrate that the 11-kDa protease is sufficient for enzymatic activity and are consistent with a major role for this form in virus maturation.

Cloning, Molecular↗
PubMed1988

Clinical observations on nail changes in psoriasis.

410 cases of psoriasis [282 males (68%) and 127 females (31%)] were interviewed and examined to study the nail changes. The prevalence of nail changes was 78.0% (males = females). Common changes were pitting (67.5%) and onycholysis (67.2%). Dystrophy of varying degrees occurred in 35.0%, subungual hyperkeratosis in 24.7%, discoloration in 18.4%, loss of nails in 2.8% and pustulation in 1.3%. Pitting and onycholysis was the most common combination (45.6%). Nail changes were significantly more common in patients who have moderate to severe psoriasis as compared with patients with mild psoriasis; in patients who have psoriasis for greater than 5 years as compared with patients who have psoriasis for less than 5 years; and in patients older than age 50 as compared with those aged less than 50. A definite correlation was found between the prevalence of nail changes and the presence of scalp and periungual psoriasis, and the presence of joint involvement.

Arthritis↗
PubMed1985

Evaluation of transport pathways for Na+ across frog skin epithelium by means of presteady-state flux ratio.

A method is described that makes it possible to separate the sodium fluxes through the isolated frog skin into sets characteristic of the cellular and the paracellular pathway, respectively. If there are two significant pathways for the ion, and if they differ with respect to flux ratio as well as mean passage time, the flux ratios for the individual pathways can be obtained from a set of inward and outward tracer fluxes, covering the time from the addition of the tracers until the achievement of constant fluxes in both directions.

Animals↗
PubMed1983

Ionic selectivity of the paracellular shunt path across rabbit corneal endothelium.

We have measured the dilution and biionic potentials across the isolated rabbit corneal endothelium in order to learn about the ionic selectivity of its intercellular junctions. Single-salt dilution potentials have been measured as a function of [NaCl] or [NaHCO3] gradients across the tissue. Biionic potentials were similarly measured by replacing Na+ with K+ on either side of the tissue. The potentials thus measured were fit to the constant field equation and to an approximation of it to obtain the ionic permeabilities for K+, HCO-3 and Cl- relative to Na+. The permeability sequence obtained was PK greater than PNa greater than PHCO3 approximately equal to PCl. Potentials were also measured after imposing an osmotic gradient across the preparation using sucrose. The results obtained with all these methods are consistent and suggest that this tissue is slightly more permeant to cations than anions, but that the selectivity of the intercellular junction is relatively low. From these experiments, a 30 mM gradient of salt across the endothelial layer would be needed in order to explain the observed spontaneous potential difference (about 1 mV, aqueous negative) across that layer if the potential was due to the selectivity of the intercellular junctions. Such a value for the gradient is much larger than theoretical estimates of it; therefore, we favor electrogenic transport of HCO-3 as a better explanation for the origin of the spontaneous potential difference.

Animals↗
PubMed1982

Analysis of presteady-state Na+ fluxes across the rabbit corneal endothelium.

Instead of the conventional steady-state fluxes, the presteady-state fluxes of 22Na across the rabbit corneal endothelium were measured. In contrast to reports that there is no net Na+ movement across the corneal endothelium, we find a net transport of Na+ across this tissue. The direction of net Na+ flux is from the stromal to the aqueous side and the magnitude is 2.3 +/- 0.4 mueq/cm2 X hr (n = 11, SEM). Net Na+ transport is inhibited in the presence of ouabain (10(-4) M). Acetazolamide (10(-4) M) has only a slight inhibitory effect on the rate of Na+ transport but decreases the transendothelial potential difference by about 30%. The passive component of the Na+ transport has been estimated by analyzing the presteady-state influx and efflux curves and found to occur 10% via cellular and 90% via paracellular routes. The analysis for the separation of the pathways has been based on a recently proposed theory which holds that the flux ratio, regardless of its driving forces, is independent of time.

Acetazolamide↗
PubMed1981

Electrical properties of rabbit corneal endothelium as determined from impedance measurements.

Alternating- and direct-current electrical characteristics of rabbit corneal endothelium were studied under varying experimental conditions. The measurements were performed by sending a 10-microA current (AC or DC) across the tissue layer. Maximal values of transendothelial potential difference and resistance were 1.3 +/- 0.1 mV and 73 +/- 6 omega . cm2, respectively. The short-circuit current was estimated from the potential and resistance values. Impedance loci were obtained for the frequency range 0.5-100 kHz. A capacitive reactance (C = 0.63 +/- 0.02 microF/cm2) was observed in the 100 Hz-100 kHz range. To relate the impedance data to the electrical parameters of the cell membranes, the voltage-divider ratio was determined by sending square pulse across the tissue and measuring voltage responses across the apical and basal membranes with an intracellular microelectrode. The intracellular potential difference was on the average -61 +/- 1 mV, and the voltage-divider ratio was found to be between 0.33 and 4. Impedance data were fit by a computer to an equivalent circuit representing a "lumped" model, and the agreement between the model and the data was satisfactory. The results are discussed in terms of both the morphological characteristics and properties of the fluid transport mechanism across the preparation.

Animals↗
PubMed1981

Na+ transport across the rabbit corneal endothelium.

It has been reported so far that the Na+ transport across the corneal endothelium is symmetrical and therefore, that there is no net transport. We now report that there is a net Na+ transport across the rabbit corneal endothelium. Instead of measuring the conventional steady-state fluxes, pre-steady state fluxes were measured as a function of time (readings were taken at two minute intervals). This technique is based on a theory, proposed very recently, that the flux ratio (efflux/influx) is independent of time. Both the efflux and influx reached their steady state values about fifteen minutes after the addition of the isotope to one side of the chamber. The net sodium flux was obtained from the difference between the steady state efflux and influx values. The direction of the net Na+ flux was from the stromal to the aqueous side, with a magnitude of 2.3 +/- 0.4 microEq/h.cm2 (n = 11, S.E.M.). The net Na+ transport was inhibited by the presence of ouabain (10(-4)M).

Animals↗
PubMed1977

Adenosine stimulation of fluid transport across rabbit corneal endothelium.

The rate of fluid transport across rabbit corneal endothelium has been measured with an automatic volumetric method. The present resolution of the procedure is 1-3 nanoliters, and intervals of measurement can be made as small as seconds. In the presence of glucose, oxidized glutathione (GSSG), and adenosine, the maximal rates were 6.2+/-1.0 microliter/hr cm2, and 8.2+/-0.8 microliter/hr cm2 if a large portion of the stroma was dissected away. In the presence of glucose and GSSG only, the rates were lower, namely 3.7+/-0.5 microliter/hr cm2. The rates consistently increased or decreased when adenosine was added or deleted, respectively, during given experiments. The stimulation of fluid transport by adenosine was in the order of 40-50%. The results raise the possibility that this transport mechanism might be subject to metabolic control.

Adenosine↗