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Biomedical subjects

V W Lee

Publications and source records attributed to V W Lee.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of castration on the lymphocytes of the thymus, spleen and lymph nodes.

It is well known that the thymus plays an important role in the development and maintenance of a competent immune system. The thymus atrophies with age, a process that is accelerated after puberty when there is elevation of serum sex steroid levels. We have used a panel of commercial monoclonal antibodies against various T and B cell surface markers to investigate the post-castration histological alterations in the thymus, spleen and lymph nodes of male Sprague-Dawley rats. Castration of 5-week-old male rats produced a significant increase in thymic weight (P < 0.05) compared to age-matched intact animals. The major observations from the immunohistochemical studies were post-castration elevations in staining for total T cells (MRC OX 19 and W 3/13), CD8 cells (MRC OX 8), B cells (MRC OX 12 and MARK-1) and cells bearing activation markers such as IL-2 receptor (MRC OX 39), transferrin receptor (MRC OX 26) and major histocompatibility class II antigen (MRC OX 6). These data suggest that following castration there is an increase in the ability of lymphocytes to respond to activation. As a result, there are elevated numbers of immature thymocytes within the thymus that undergo differentiation/maturation and consequently produce an increase in peripheral T and B cells.

Animals↗
PubMed1998

An analysis of the incidence and risk factors of developing severe keratopathy in eyes after megavoltage external beam irradiation.

OBJECTIVE: To investigate the incidence and risk factors of developing severe keratopathy in eyes exposed to megavoltage external beam irradiation. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: The authors evaluated 88 eyes of 88 consecutive patients who had received irradiation of an entire orbit during radiation therapy for nasopharyngeal carcinoma. Mean follow-up was 40 months (range, 24-106 months). INTERVENTION: Slit-lamp biomicroscopic findings of the cornea after irradiation were categorized into four grades in accordance with a standard protocol. Grade 3 or above changes were defined as severe radiation keratopathy. MAIN OUTCOME MEASURES: The incidence of severe radiation keratopathy was evaluated along with patient's age, radiation dose, lacrimal shielding, and tumor involvement of the trigeminal nerve. RESULTS: Severe radiation keratopathy developed in 32 patients. Mean latency was 15 months (range, 4-36 months). Its incidence increased from 0% after doses less than 59 Gy to 100% after doses greater than 70 Gy. Between 59 Gy and 69 Gy, the adverse factor was omission of lacrimal shield during radiation therapy (P < 0.01). CONCLUSION: Radiation dose to the cornea is the most important factor in determining the outcome of radiation keratopathy. When the threshold dose is reached, visual prognosis is grave despite protection of the lacrimal gland. Clinical trials on newer strategies to treat ocular surfaces exposed to heavy irradiation are necessary.

Adult↗
PubMed1998

Scintigraphic functional hyposplenism in amyloidosis.

UNLABELLED: Functional asplenia or hyposplenism may predispose patients to spontaneous splenic rupture and potentially increase the risk of serious infection. In addition, hyposplenism may be a marker of more extensive systemic amyloidosis and has been correlated to a reduction in survival. Decreased splenic function is generally diagnosed by the presence of abnormal red blood cell morphology and decreased splenic uptake on 99mTc-sulfur colloid or microlite scans. We compared liver spleen scans with red cell morphology and anatomic imaging results in all patients with biopsy-proven amyloidosis who presented to the nuclear medicine department over a 12-yr period. Patients were referred from a center for amyloid disease for work-up of suspected hepatic involvement. METHODS: Between 1983 and 1995, 23 liver spleen scans from 21 patients (one patient had three scans) with known amyloidosis were referred for the assessment of degree of hepatic involvement with amyloid. All scans were retrospectively reviewed, and the degree of splenic uptake was graded. Medical records were reviewed for evidence of splenomegaly on physical exam. Extent of splenic involvement also was assessed by anatomical imaging (CT or MRI) in 45% of cases. Peripheral smear reports were reviewed for the presence of abnormal red cell morphology consistent with hyposplenism. RESULTS: Splenic activity was moderately or markedly reduced in 22 of 23 liver spleen scans (21 patients). Eight of these scans had correlative anatomic splenic imaging: four were abnormal and four were normal. Forty-one percent of available peripheral smears contained abnormal red cell morphology. Nine patients had palpable splenomegaly at the time of the liver spleen scan. Splenic pathologic studies were available for three patients (two autopsy, one surgical) and demonstrated diffuse splenic infiltration with amyloidosis. One patient had spontaneous splenic rupture. Fourteen patients died, four of overwhelming infection. CONCLUSION: Reduced splenic uptake on liver spleen scans for patients with suspected hepatic infiltration with amyloid is a common finding. Liver spleen scanning appears to be a more sensitive marker of splenic amyloidosis than clinical parameters or anatomical imaging.

Adult↗
PubMed1994

Pulmonary mycobacterial infections in AIDS: characteristic pattern of thallium and gallium scan mismatch.

PURPOSE: To evaluate the diagnostic specificity of thallium and gallium scan mismatch as a sign of mycobacterial infection in immunodeficient patients. MATERIALS AND METHODS: Thallium and gallium scans obtained in 56 immunodeficient patients between January 1989 and March 1994 were retrospectively reviewed, with special attention to the final diagnoses in all patients with thallium-gallium scan mismatch compared with those whose scans showed other scintigraphic patterns. RESULTS: Fourteen patients had focal gallium uptake, but no thallium uptake, in the mediastinum and hilar nodes (thallium-gallium mismatch). Twelve of the 14 had culture-proved mycobacterial infections; one had cryptococcal infection; and in one, the diagnosis was not established. Thirty-seven of the remaining 42 patients who had different scintigraphic patterns on thallium-gallium scans had other complications of acquired immunodeficiency syndrome such as Kaposi sarcoma, non-Hodgkin lymphoma, and bacterial pneumonia. The diagnosis in five of the 42 patients was not known because follow-up data were incomplete. CONCLUSION: The thallium-gallium mismatch pattern in immunodeficient patients is specific for mycobacterial infection.

AIDS-Related Opportunistic Infections↗
PubMed1993

Effect of prepubertal gonadectomy and sex steroid treatment on the growth and lymphocyte populations of the rat thymus.

The age at which rats are most sensitive to prepubertal gonadectomy, in terms of thymic growth, was investigated. Gonadectomy enhanced thymic growth at each age; the greatest difference in thymic weight between gonadectomized and intact animals occurred in male rats gonadectomized at 5 weeks of age (64%) and in female rats gonadectomized at 4-5 weeks of age (43-46%). The effect of various synthetic sex steroids on growth and lymphocyte populations of the thymus in gonadectomized rats was examined. Diethylstilboestrol, 1 mg per animal, inhibited thymic growth by more than 35% in both males and females. Ethinyloestradiol, 40 micrograms per animal, inhibited thymic growth by 26% in males but by only 4% in females. Fluoxymesterone, 10 mg per animal, inhibited thymic growth by more than 46% in both sexes. Norgestrel, 12 micrograms per animal, had no effect on thymic growth. The synthetic steroids that significantly inhibited thymic growth decreased the intensity and altered the localization of staining for total T cells (antibody clone MRC OX 19), T helper cells and macrophages (W 3/5), T cytotoxic/suppressor cells (MRC OX 8) and B cells (MRC OX 12).

Aging↗
PubMed1993

A complementary role for thallium-201 scintigraphy with mammography in the diagnosis of breast cancer.

Physical examination and mammography are currently the only proven and reliable methods of early detection of breast cancer. Although both procedures are highly sensitive, their limited specificity often requires surgical biopsy in order to differentiate between malignant and benign lesions. The purpose of this prospective study is to investigate the diagnostic specificity of thallium imaging for breast cancer and to determine its efficacy as a complement to mammography. Two groups were studied: Group A: Patients found to have breast abnormalities and scheduled for biopsy or surgery and Group B: Patients who were suspected to have a recurrence of cancer after mastectomies or lumpectomies. In Group A, thallium scans of 32 breasts in 30 patients were performed prior to biopsy or surgery, yielding pathological diagnoses of 31 breasts in 29 patients. Results for Group A included seven true-positive thallium scans, twenty-two true-negative scans, two false-negative scans, and one false-positive scan. In Group B, seven patients were scanned to evaluate subcutaneous nodules for breast cancer following mastectomy or lumpectomy. Results for Group B included five true-positive scans, one true-negative scan, one false-negative scan and no false-positive scans. Thallium breast scanning was shown to have high specificity for cancer (specificity 96% and sensitivity 80%), suggesting that this technique should be evaluated in additional patient studies to determine its role in clinical situations.

Adult↗
PubMed1992

Heat-related changes to the hydrophobicity of cheese whey correlate with levels of native beta-lactoglobulin and alpha-lactalbumin.

Correlations were identified between levels of the native whey proteins, beta-lactoglobulin and alpha-lactalbumin and the surface and total hydrophobicities of cheese whey in response to different heat treatments. Heat-induced changes in the native beta-lactoglobulin content and surface hydrophobicity of whey exhibited the most significant linear relationship while correlations between total hydrophobicity and the native proteins were less significant because of an atypical rise in the n-heptane-binding capacity of whey after high-temperature treatment. The content of native beta-lactoglobulin in whey was more sensitive to heating than the content of native alpha-lactalbumin, while heat-related changes in the total hydrophobicity of whey were generally greater than similar changes in surface hydrophobicity.

Cheese↗
PubMed1992

The clinical significance of myocardial contusion.

In an attempt to identify a group of blunt trauma victims with asymptomatic myocardial contusion (MC) who do not benefit from intensive cardiac monitoring, we prospectively divided 336 patients admitted to the SICU with possible MC following blunt trauma in the 6 years prior to January 1990 into three groups: Group 1 (n = 155, age 30.5 +/- 9 years) consisted of those patients admitted for mechanism of injury, J-point elevation, with or without minor chest injury. None developed arrhythmias. Their SICU length of stay (LOS) was 2.41 +/- 0.77 days. Group 2 (n = 43, age 31.5 +/- 10 years) patients had the same admission criteria as the patients in group 1 plus an abnormal emergency department ECG, i.e., arrhythmia, heart block, ischemia. None had cardiac complications. Their SICU LOS was 2.47 +/- 0.94 days. Group 3 (n = 138, age 40 +/- 20 years) patients had four or more rib fxs, a pulmonary contusion, a flail chest, or extra-thoracic injuries or were greater than 60 years of age. All required SICU admission for their non-cardiac injuries. Nineteen patients had cardiac complications requiring treatment. None had a cardiac death. Their SICU LOS was 10 +/- 22 days. We conclude that young patients with minor blunt thoracic trauma and a normal or minimally abnormal ECG do not benefit from cardiac monitoring.

Adult↗
PubMed1992

Conjugated anti-TNF antibodies enhance the binding and degradation of TNF.

We have used disulfide-linked conjugates of murine anti-TNF antibodies to determine whether TNF binding to the cell surface could be increased by exploiting the Fc receptors present on monocytes and macrophages. Binding and degradation of TNF via Fc receptors may enhance the ability of anti-TNF antibodies to lower the high TNF levels found in several diseases. Conjugated murine anti-TNF antibodies greatly increased the binding of TNF to human U937 cells and had little effect on cells which did not express Fc receptors. U937 cells treated with anti-TNF conjugates also degraded more TNF than untreated cells. Competition analysis indicated that Fc receptors were involved in anti-TNF binding and that conjugated anti-TNF shared binding sites with monomeric anti-TNF. Preincubation of anti-TNF conjugates or monomeric anti-TNF with TNF increased the amount of anti-TNF antibody bound to the surface of cells. These results demonstrate that cross-linking may greatly enhance the ability of anti-TNF antibodies to mediate TNF clearance and degradation by making effective use of Fc receptors.

Animals↗
PubMed1991

Pulmonary Kaposi sarcoma in patients with AIDS: scintigraphic diagnosis with sequential thallium and gallium scanning.

Pulmonary Kaposi sarcoma associated with acquired immunodeficiency syndrome (AIDS) is difficult to diagnose because the clinical presentations and radiographic findings are nonspecific. The authors report three proved cases of AIDS-associated pulmonary Kaposi sarcoma diagnosed with sequential thallium and gallium scans. These scans demonstrated abnormal increase of pulmonary thallium uptake, whereas the gallium uptake was negative. In the authors' experience and in reports in the radiology literature, infected areas of the chest are generally thallium-negative on the delayed (3-hour) scans but are gallium-avid, whereas lymphomas are both thallium- and gallium-avid. The authors conclude that sequential thallium and gallium scans can be used to help diagnose pulmonary Kaposi sarcoma and distinguish it from other common AIDS-associated chest complications such as lymphoma and infections.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Agenesis or hypoplasia of major salivary and lacrimal glands.

We described a young man with almost total absence of the parotid glands, hypoplasia of both lacrimal glands, marked hypofunction of both submandibular glands, and left nasolacrimal duct atresia. Lack of tearing, severe dental caries, and conjunctival scarring following chronic xerophthalmia and conjunctivitis serve to alert pediatricians to this autosomal dominant disorder with considerable variation in expressivity.

Abnormalities, Multiple↗
PubMed1990

Subcutaneous Kaposi's sarcoma. Thallium scan demonstration.

A case of AIDS-related Kaposi's sarcoma involving subcutaneous tissues beyond the visible skin lesions is reported. In this case, the tumor was thallium avid. Thallium scintigraphy was able to demonstrate the true extent of the tumor and may be used to document the presence and extent of cutaneous and extracutaneous AIDS-related Kaposi's sarcoma.

Acquired Immunodeficiency Syndrome↗