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Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 649 records · Page 36Linked to original sources
PubMed1994

Keratocyte loss after different methods of de-epithelialization.

PURPOSE: To evaluate the response of corneal stromal cells to different types of superficial injury. METHODS: Twenty-two rabbits were randomized into five groups of four (with 2 untreated controls), and their corneas de-epithelialized (1) with a blunt instrument alone; (2) with an instrument and application of 100% ethanol, 0.5% proparacaine, or 4% cocaine; or (3) with the excimer laser. Twenty-four hours after surgery, the eyes were enucleated, and histologic changes were quantitated. RESULTS: All the methods of de-epithelialization used resulted in a decrease in the number of keratocytes relative to the control numbers (P = 0.0001). There is a significantly greater decrease in keratocyte counts with 0.5% proparacaine and 100% ethanol when compared with eyes injured by mechanical means, with 4% cocaine, or with the excimer laser (P = 0.009). All treatment groups showed more polymorphonuclear leukocytes than did controls (P < 0.0001). Mechanical de-epithelialization alone or in conjunction with proparacaine produced the least inflammatory response, but de-epithelialization with the laser was associated with a greater inflammatory response (P < 0.0001). CONCLUSIONS: All methods of de-epithelialization produced a significant decrease in rabbit cornea stromal keratocytes 24 hours after injury, associated with acute inflammation. Thus, it may be appropriate to avoid using chemicals, or if chemicals are used, to at least avoid using 100% ethanol. The applicability of these findings to humans has not yet been established.

Animals↗
PubMed1994

Epidemiologic background and long-term course of disease in human immunodeficiency virus type 1-infected blood donors identified before routine laboratory screening. Transfusion Safety Study Group.

BACKGROUND: The long-term course of human immunodeficiency virus type 1 (HIV-1)-related disease among seropositive blood donors has not been described. The enrollment and epidemiologic background of HIV-1-infected donors in the Transfusion Safety Study and their immunologic and clinical progression are described. STUDY DESIGN AND METHODS: Through the testing of approximately 200,000 sera from donations made in late 1984 and early 1985, 146 anti-HIV-1-positive donors and 151 uninfected matched donors were enrolled. These two cohorts were followed with 6-month interval histories and laboratory testing. RESULTS: Seropositive donors detected before the institution of routine anti-HIV-1 screening disproportionately were first-time donors and men with exclusively male sexual contacts. The actuarial probability of a person's developing AIDS within 7 years after donation was 40 percent; the probability of a person's dying of AIDS was 28 percent. AIDS developed more often when the donor was p24 antigen-positive at donation. Over a 3-year period, significant decreases occurred in CD4+, CD2+CD26+, CD4+CD29+, and CD20+CD21+ counts, but not in CD8+ subsets, CD20+, or CD14+. CONCLUSION: The high proportions of first-time donations and exclusively homosexual men among seropositive donors suggest that test-seeking may have contributed to the high HIV-1 prevalence in the repository. Implementation of alternative test sites when routine donor screening began in 1985 may have averted many high-risk donations. The disease course in HIV-1-infected donors had the same wide spectrum of immunologic and clinical manifestations as were reported for other cohorts.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Stereotactic biopsy of 100 intracerebral lesions at Sir Charles Gairdner Hospital.

The pathological findings in a retrospective review of 100 consecutive intracranial stereotactic biopsies are presented. Definite diagnosis could be established in the majority (89) of cases and included 85 neoplasms (69 primary cerebral tumors, 10 non-Hodgkin's lymphomas and 6 metastases) and 4 non-neoplastic processes. In the remaining 11 samples the findings were non-diagnostic; 2 consisted of normal glial tissue, while the remainder variously showed changes of necrosis, hematoma, histiocytic reaction or astrocytic proliferations of uncertain nature. Verification of the stereotactic diagnosis by examination of lesional tissue obtained at subsequent craniotomy or postmortem was possible in 7 of 10 cases. Two broad categories of diagnostic difficulty were identified in interpreting stereotactic biopsies: (1) accurate tumor typing and grading, and (2) the distinction between reactive and neoplastic astrocytic proliferations. Two essential components in the diagnostic process are: (1) careful correlation with the clinical and radiological findings; and (2) use of intraoperative smear and/or frozen section preparations to confirm specimen adequacy. By adhering to these principles accurate intraoperative diagnosis can usually be established, particularly for high grade astrocytoma, lymphoma and metastasis. Tumor typing is aided by the use of immunohistochemistry and ultrastructural examination and the examination of serial sections is of value in grading.

Adolescent↗
PubMed1994

The effect of recovery from depression on preferences for life-sustaining therapy in older patients.

BACKGROUND: This study compared older veterans' preferences about life-sustaining therapy before and after treatment for depression in order to determine whether recovery from depression is associated with an increase in the desire for these interventions. METHODS: Medical inpatients over 65 years of age were eligible. Depressed subjects scored > 14 on the Geriatric Depression Scale and were independently diagnosed by a psychiatrist as depressed. A questionnaire quantified preferences regarding potentially life-sustaining interventions currently, and in four hypothetical scenarios of illness. RESULTS: Initial interviews were completed on 50 depressed and 50 nondepressed subjects. Within 6 months, 34 (68%) depressed and 40 (80%) control subjects were reevaluated. Preferences did not change significantly from initial to final interview, regardless of whether subjects had recovered from depression or remained depressed. With the exception of cardiopulmonary resuscitation, however, control subjects' preferences were more stable than depressed subjects' choices. CONCLUSIONS: This study demonstrated that treatment of mild-to-moderate depression does not necessarily result in an increased desire for life-sustaining medical therapy. Because depressed patients exhibit less consistency in their preferences over time, we advise careful and repeated discussions with the depressed patient regarding these decisions.

Aged↗
PubMed1994

Interleukin-2 in neoadjuvant therapy potentiates inhibitory activity of 5-fluorouracil and interferon in experimental liver metastases.

Our previous studies showed that interferon (IFN) used in combination with 5-fluorouracil (5-FU) was effective in inhibiting colorectal tumor cell metastases to the liver in nude mice. Furthermore, IFN was also effective in neoadjuvant therapy and allowed the combination treatment (5-FU + IFN) to be delayed for 2-3 weeks following i.s. injections of tumor cells. In this study, we have examined the potential of interleukin-2 (IL-2) to substitute for IFN in neoadjuvant therapy. IL-2 was found to be equally effective, if not superior, to IFN as a neoadjuvant in inhibiting liver and lung metastases with 5-FU + IFN. Moreover, the effect of IL-2 was demonstrable even after 1 week, whereas IFN did not have an effect until 2 weeks of neoadjuvant dosing. These studies demonstrate IL-2 to be more effective than IFN as an immunomodulatory agent in combination with 5-FU + IFN for the inhibition of liver metastases in nude mice.

Animals↗
PubMed1994

Focal nodular hyperplasia of the liver.

The management of focal nodular hyperplasia (FNH) of the liver requires a systematic approach. After a histologic diagnosis of FNH is obtained, asymptomatic lesions can be observed safely with regular follow-up and treated if they become symptomatic or enlargement occurs. In the case presented here, we have elected follow-up with serial CT scans because our patient is asymptomatic and the lesion has not significantly enlarged. Patients who have symptomatic lesions while taking an oral contraceptive can have conservative follow-up when they stop taking the oral contraceptive, because regression of FNH has been reported to occur after cessation of oral contraceptive use. If the patient remains symptomatic or if the lesion enlarges after discontinuance of oral contraceptive use, surgical resection is warranted. Other symptomatic patients, including those with a previous history of taking oral contraceptives, should be treated by surgical resection or, when resection is not possible, by embolization or ligation of the hepatic artery, because symptomatic patients are at risk for having malignant lesions misdiagnosed as FNH.

Female↗
PubMed1994

Eosinophilic gastroenteritis manifesting with ascites.

Eosinophilic gastroenteritis (EGE) is a rare condition of unknown cause characterized by peripheral eosinophilia, eosinophilic infiltration of the gastrointestinal tract, and gastrointestinal symptomatology. EGE is generally classified according to the layer of gastrointestinal tract involved. Mucosal involvement, the most common form of presentation, may result in abdominal pain, nausea, vomiting, diarrhea, anemia, and protein-losing enteropathy. Patients with muscular layer disease generally have gastrointestinal obstruction. Serosal eosinophilic infiltration, the rarest form of presentation, may result in development of eosinophilic ascites. EGE complicated by ascites can be effectively treated with steroids after other systemic disorders associated with peripheral eosinophilia have been ruled out.

Abdominal Pain↗
PubMed1994

Immunoglobulin replacement in patients with chronic lymphocytic leukaemia: a comparison of two dose regimes.

Previous studies have shown that intravenous immunoglobulin (IVIg) therapy is useful prophylaxis against infection in patients with secondary hypogammaglobulinaemia due to a low-grade lymphoproliferative disease. This randomized double-blind study was undertaken to determine prospectively the dose regime required. 34 such patients received IVIg at either 500 or 250 mg/kg every 4 weeks for 1 year. There was no significant difference in the rates of serious infections between the two groups of patients, which were well matched for disease and laboratory parameters. The rates of infection seen were similar to those in IVIg groups of previous studies and strikingly different from those in the placebo group in the previously randomized placebo-controlled study.

Aged↗
PubMed1994

Synthesis and biological activity of locust AKH-I and its analogues with modifications at the threonine residues.

A convenient method of synthesis, using a combination of solid and liquid phase methodology, for locust Adipokinetic Hormone-I (AKH-I) and its analogues with modifications at the threonine residues are reported. The N-terminal nonapeptide acid of AKH-I is synthesized in the solid phase using the 2-chlorotrityl chloride resin and the Fmoc/t-Bu strategy. Quantitative cleavage of the nonapeptide acid from the resin, with the tert-butyl type side-chain protection intact, is achieved with a mixture of acetic acid/trifluoroethanol/dichloromethane. The nonapeptide acid is then coupled in solution to the threonine derivatives, H-Thr-NH2 or H-Thr(Bzl)-NH2, with the DCC/HOBt method. The efficiency of this approach in the synthesis of AKH-I is demonstrated by the high yields and purity of the synthesized peptides. All the synthesized peptides were tested in two ways: first, in a lipid mobilization assay in locusts in vivo; and second, in a novel assay in vitro concerned with the uptake of radiolabelled acetate into locust tissue. Replacement of the hydroxyl hydrogen in Thr5 of locust AKH-I by the bulky and highly lipophilic tert-butyl group reduced the potency markedly, whereas efficacy is unaffected, but when the hydroxyl hydrogen of Thr10 in AKH-I is replaced by a benzyl group, the activity of the resulting analogue is identical to that of the natural peptide. Structure-activity relationships are discussed.

Amino Acid Sequence↗
PubMed1994

Ocular surface damage and tear lactoferrin in dry eye syndrome.

We studied the relationship between the severity of ocular surface damage and the level of tear lactoferrin in primary and secondary Sjögren's syndrome and keratoconjunctivitis sicca not associated with Sjögren's syndrome. A significant negative correlation was found between Rose Bengal staining score and level of tear lactoferrin in all three groups. Analysis of covariance disclosed no significant differences in regression lines for Rose Bengal staining score vs tear lactoferrin level among the three groups. The three regression lines appeared to be identical to each other. These findings indicate that the severity of ocular surface damage due to dry eye largely depends on the tear secretory function of the lacrimal gland, and that the function of the lacrimal gland can be evaluated by determination of level of tear lactoferrin using the same standards regardless of differences in pathogenesis of underlying diseases.

Adolescent↗
PubMed1994

Management of hydrocephalus in children with medulloblastoma: prognostic factors for shunting.

Patients with medulloblastoma frequently present with hydrocephalus. While not all patients with medulloblastoma will continue to suffer from hydrocephalus after tumor resection, there is a significant proportion who will require a permanent shunt. We have retrospectively reviewed a group of children with medulloblastoma not shunted preoperatively, and have identified several characteristics which are associated with a requirement for permanent shunt. We studied 42 patients and found that 17 patients (40%) required permanent shunts within 4 weeks of craniotomy. The shunted patients were younger (5.4 +/- 2.9 vs. 10.0 +/- 5.7 years; p < 0.01), had larger ventricles (p < 0.05), and had more extensive tumors (Chang's stage T3 and T4; p < 0.01). These variables were all independently significant. In addition, we found that the patients requiring postcraniotomy shunts had a much higher rate of morbidity including a postoperative pseudobulbar syndrome. Of interest, we found that none of our patients without the above characteristics required a shunt. In particular, we found that no patient older than 10 years required a shunt. Thus, we conclude that younger patients with moderate to severe preoperative hydrocephalus and extensive tumors may benefit from perioperative CSF diversion. Other patients not meeting the above criteria can probably be safely managed with perioperative corticosteroids alone.

Adolescent↗
PubMed1994

Depressed skull fractures in children secondary to skull clamp fixation devices.

The use of external skull fixation devices (skull clamps) is a common practice in neurosurgery. The insertion of pins into the skull is usually routine and uneventful in adult patients. However, the safety of skull clamp fixation devices in children is not reported. We have examined our complications over the past 6 years, and have encountered 5 children with depressed skull fractures secondary to application of a skull clamp fixation device. There were 3 boys and 2 girls with ages ranging from 3 to 8 years (mean 5.8 years). Two patients had brainstem gliomas, 2 patients had hypothalamic gliomas and 1 patient had a medulloblastoma. Four of the children required separate cranial procedures for exploration and elevation of the depressed fractures. There were no sequelae associated with the depressed fractures. We conclude that skull clamp fixation devices are safe, but should be used with caution in the pediatric patient. In addition, we present several modifications of existing skull clamps which may decrease the risk of depressed skull fractures.

Brain↗
PubMed1994

Hyperhidrosis--a case history.

The authors present a case report on hyperhidrosis. The social and occupational consequences of this disease entity are discussed as well as the genetic implications of this disorder. The medical and surgical treatments of hyperhidrosis are evaluated. The use of infrared imaging techniques as a cost-effective, rapid, noninvasive procedure to diagnose this disorder is described.

Female↗
PubMed1994

Cardiovascular changes during continuous hyperthermic peritoneal perfusion.

Changes in blood temperature, hemodynamics, and oxygen transport were evaluated in 11 patients during continuous hyperthermic peritoneal perfusion (CHPP), a technique in which the peritoneal cavity is perfused continuously with heated solution to treat intraperitoneal cancer. CHPP was undertaken 46.8 min after the resection of cancer. Blood temperature, measured with a thermistor of a pulmonary artery catheter, reached 39.2 degrees C. Heart rate increased to 100.7 +/- 21.4 bpm (mean +/- SD) and the cardiac index to 4.61 +/- 0.80 L.min-1.m-2. Mean arterial pressure decreased to 75.5 +/- 10.8 mm Hg and systemic vascular resistance index to 1239 +/- 394 dynes.s.cm-5.m2. Oxygen consumption greatly increased to 139.1 +/- 35.2 mL.min-1.m-2, concurrently with a smaller increase in oxygen delivery to 619.7 +/- 83.7 mL.min-1.m-2 and a slight increase in oxygen extraction. Pulmonary oxygenation capacity was also disturbed. Although these cardiovascular changes were mainly due to systemic hyperthermia, other changes may be caused by splanchnic heating, abdominal distention, and pharmacologic action of methoxamine, propranolol, diltiazem, and fentanyl.

Adult↗
PubMed1994

A near-fatal complication of endoscopic third ventriculostomy: case report.

The authors treated a 14-year-old girl with posthemorrhagic hydrocephalus and an infected ventriculopleural shunt. She was taken for endoscopic third ventriculostomy with the hope of removing the hardware entirely, but she developed an arrhythmia and hypertension, followed rapidly by complete cardiac arrest. She was resuscitated successfully, made a complete recovery, and subsequently underwent a conventional shunt replacement. This is a newly reported life-threatening complication of neuroendoscopy that must be anticipated by any surgeon undertaking such a procedure.

Adolescent↗