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Biomedical subjects

J Koo

Publications and source records attributed to J Koo.

At least 55 records · Page 3Linked to original sources
PubMed1997

Enteric duplication in the adult, derived from the foregut, midgut and hindgut: presentation, patterns and literature review.

Duplication of the alimentary tract may affect patients of all ages. Although they are relatively rare, the importance of these congenital lesions lies in the fact that they readily mimic other surgical disease processes and may result in significant morbidity if left untreated. Prompt recognition and treatment using combined radiologic and surgical management are generally associated with an excellent outcome. Three patients who presented with intestinal duplication arising from each of the major embryologic origins are reported. Their clinical histories reveal the spectrum of presentation associated with these lesions and provide a framework for a discussion of current management strategies.

Adult↗
PubMed1997

Calcipotriol/calcipotriene (Dovonex/Daivonex) in combination with phototherapy: a review.

BACKGROUND: Calcipotriol/calcipotriene (Dovonex/Daivonex) ointment plus phototherapy has been used in the treatment of psoriasis. OBJECTIVE: We will attempt to clarify two issues: First, is there any benefit to combining the above treatment modalities? Second, is there any increased risk associated with the use of the combination? METHODS: A complete review of the literature revealed four studies dealing with the combination of calcipotriol with UVB phototherapy and three studies dealing with the combination of calcipotriol with PUVA phototherapy. RESULTS: These studies showed an advantage to the use of the combination compared with the use of either treatment alone. CONCLUSION: Topical calcipotriol enhances the effect of UVB and PUVA phototherapy.

Calcitriol↗
PubMed1996

Comparison of once-daily versus pharmacokinetic dosing of aminoglycosides in elderly patients.

PURPOSE: Once-daily dosing has been suggested as an alternative method of dosing aminoglycosides that would reduce their toxicity while maintaining efficacy. There have been no studies published to date comparing once-daily dosing and pharmacokinetic dosing of aminoglycosides. We conducted a randomized controlled trial comparing the safety and effectiveness of 4 mg/kg IV once-daily dosing of gentamicin or tobramycin with a pharmacokinetic dosing method using an initial dose of 2 mg/kg IV every 12 hours. PATIENTS AND METHODS: Ninety-six patients were randomly assigned to either the once-daily dosing group (4 mg/kg) or the pharmacokinetic dosing group (initial dose of 2 mg/kg every 12 hours). In the once-daily dosing group, the dosing interval was extended by 12 to 24 hours to maintain a serum trough concentration < 1.5 mg/L regardless of the peak concentration. Dosing in the other group was adjusted based on the individual pharmacokinetic data to achieve a serum peak concentration of 6 to 10 mg/L and a trough concentration below 1.5 mg/L. The patients studied were predominantly elderly males (mean age 69 years). All patients were assessed for treatment efficacy and nephrotoxicity. RESULTS: There was no significant difference between the two groups with regard to clinical and bacteriologic efficacy. Incidence of nephrotoxicity was 24% in the once-daily group and 14% in the pharmacokinetic dosing group but the difference was not statistically significant (P = 0.13). Unlike previous studies, we found a correlation between high serum peak concentration and incidence of nephrotoxicity in the once-daily dosing group. Nephrotoxicity developed in six out of 10 patients (60%) with an initial serum peak concentration greater than 12.0 mg/L compared to two out of 24 patients (8.3%) with an initial peak concentration less than 12.0 mg/L (P < 0.001) in the once-daily group. Serum peak concentrations in the pharmacokinetic dosing group were not correlated with nephrotoxicity. CONCLUSIONS: Once-daily dosing and pharmacokinetic dosing of aminoglycosides appear to have equal efficacy and toxicity. However, in the elderly population, high serum peak concentrations that occur with once-daily aminoglycoside dosing may increase the risk of nephrotoxicity.

Aged↗
PubMed1996

Delusions of parasitosis and other forms of monosymptomatic hypochondriacal psychosis. General discussion and case illustrations.

In this article, the epidemiology and differential diagnosis of monosymptomatic hypochondriacal psychosis are discussed in detail. The use of pimozide is also discussed and illustrated with case reports. Delusional patients are some of the most challenging cases based in dermatologic practice. This challenge is so much easier to meet if one knows how to approach these patients and feels comfortable in the use of pimozide.

Adult↗
PubMed1996

Population-based epidemiologic study of psoriasis with emphasis on quality of life assessment.

With the changing health care scene in the United States, it is important to have up-to-date epidemiological data with regard to the prevalence of psoriasis in the United States. It is also becoming more important to develop a psychometric instrument that is useful in assessing quality of life issues among psoriasis patients. The Psoriasis Disability Index, which was developed in England, may not be optimally applicable in assessing quality of life issues among psoriasis patients seen by American dermatologists. In this article, the latest nationwide population-based epidemiologic data on psoriasis are presented, along with the use of a new psychometric questionnaire that emphasizes the assessment of quality of life rather than disability.

Adolescent↗
PubMed1996

Cutaneous sensory disorder.

Some patients only present with a cutaneous sensory complaint such as itching, burning, stinging, or other disagreeable sensations of unknown etiology. Frequently, these patients may not have any diagnosable dermatologic, neurologic, medical, or psychiatric diagnosis. Their suffering, however, is real. This article explains a practical approach to the treatment of patients with pure cutaneous sensory disorders.

Analgesics↗
PubMed1996

Psychopharmacology for dermatologic patients.

In the recent past, there has been great progress made in making psychopharmacologic agents both more efficacious and more user friendly. If dermatologists are to more effectively treat psychodermatologic patients who refuse to see a mental health professional, judicious and responsible use of psychopharmacology is still the most feasible way to treat many of these patients. This article illustrates the use of several commonly used psychopharmacologic agents. Even for psychiatrists, it is not realistic to try to master all psychopharmacologic agents that are on the market. Familiarity with the use of medications discussed in this article is likely to add significantly to the therapeutic armamentarium of a dermatologic practitioner.

Antipsychotic Agents↗
PubMed1996

Pseudopsychodermatologic disease.

Just as psychodermatologic disorders can mimic real dermatologic conditions, real dermatologic or other bona fide physical problems such as neurologic disorders can also mimic psychodermatologic disorders. This article illustrates several cases of pseudopsychodermatologic disorders. When faced with a difficult patient or baffling case, sometimes there is a tendency to "jump to conclusions" with regard to the psychogenic origins of the case. It is important to be cognizant of the possibility that one may be missing a real organic disorder if one does not keep an open mind with regard to diagnosis of the patient's skin condition.

Adult↗
PubMed1996

The severity of nauseogenic effect of cross-coupled rotation is proportional to gyroscopic angular acceleration.

METHOD AND RESULTS: Subjects underwent cross-coupled rotation of the head (i.e., Coriolis stimuli) during which the upper body was tilted from side to side during horizontal rotation of the whole body about the Earth-vertical axis. In Experiment 1, the angle between the two axes of cross-coupled rotation was changed to vary the magnitude of gyroscopic angular acceleration without wide variations in Coriolis linear acceleration. The severity of nausea evoked by cross-coupled rotation stimuli varied relative to the magnitude of gyroscopic angular acceleration. It is noteworthy that nausea was not evoked unless gyroscopic angular acceleration was generated, even though Coriolis linear acceleration was equally induced. In Experiment 2, subjects tilted the upper body with or without restriction of head movement to a vertical plane during Earth-vertical axis rotation of the body at various angular velocities. The severity of evoked nausea was in direct proportion to angular velocity of body rotation irrespective of the restriction. CONCLUSION: These results indicated that the severity of nauseogenic effect of cross-coupled rotation is directly proportional to gyroscopic angular acceleration.

Acceleration↗
PubMed1995

Cyclic compressive loading results in fatigue cracks in ultra high molecular weight polyethylene.

Wear damage to the articulating surfaces of total joint components made of ultra high molecular weight polyethylene is associated with a fatigue fracture mechanism, despite the fact that these surfaces are subjected to primarily compressive and compressive-tensile cyclic stresses. The question arises as to whether fatigue cracks will form under such loading conditions. In this study, we experimentally demonstrated that fatigue cracks could be initiated and propagated in notched ultra high molecular weight polyethylene specimens subjected to fully compressive and compressive-tensile cyclic loading. Under these loading conditions, growth of fatigue cracks was limited: the cracks arrested without catastrophic failure of the test specimens. The final length of the crack was dependent on the load ratio of the fatigue cycle; fatigue cracks propagated to greater lengths as the load ratio was increased.

Knee Prosthesis↗
PubMed1995

Increase of a urokinase receptor-related low-molecular-weight molecule in colorectal adenocarcinomas.

Proteolytic activity is important for tumor growth and metastasis. Plasminogen and urokinase-type plasminogen activator (u-PA) constitute one of the most extensively studied proteolytic systems believed to participate in these processes. u-PA cleaves plasminogen to plasmin, which in turn degrades surrounding extracellular matrix and allows tumor cells to migrate to other areas. The specific receptor for u-PA (u-PAR) has also been implicated as an essential modulator in this pathway. Eleven paired samples of colorectal cancers and normal mucosal tissues from the same patients were removed at surgery. The tissues were homogenized and the supernatants assayed for u-PAR immunoreactivity, u-PAR antigen concentration, u-PAR binding activity and u-PA activity. Immunoblot analysis showed that a major u-PAR species of approximately 55 kDa was present in all tissues. In addition, a protein band of approximately 41 kDa, which crossreacted with anti-u-PAR antibodies, was also found in the tumors. This protein band was either absent, or present in relatively small amounts in the normal colorectal tissues. Cross-linking experiments showed that the approximately 55 kDa band only, and not the approximately 41 kDa band, was able to bind either single chain urokinase-type plasminogen activator (scu-PA) or the amino terminal fragment of urokinase (ATF). The tumor samples also exhibited highly elevated u-PA activity and u-PAR antigen relative to the corresponding normal tissues. Elevated u-PA activity appeared to correlate with elevated u-PAR antigen in colorectal cancers, but not in the normal tissues. These increases were also associated with increase of the u-PAR-related, low-molecular-weight protein in the tumor samples. The measurement of u-PAR and the u-PAR-related protein, in addition to u-PA activity, could have diagnostic or prognostic value in this type of cancer.

Adenocarcinoma↗
PubMed1995

The effect of extended lymphadenectomy on survival in patients with gastric adenocarcinoma.

BACKGROUND: In the United States of America, the five-year survival rate among patients surviving curative resection for gastric carcinoma will range between 20 and 25 percent. In Japan, early diagnosis and an aggressive surgical approach including planned lymph node dissection has resulted in the five-year survival rate exceeding 50 percent for all patients with newly diagnosed gastric carcinoma. This report is a retrospective review evaluating the effect of extended lymph node dissection (D2) on overall survival in 101 patients with gastric adenocarcinoma who underwent a potentially curative gastric resection from 1975 to 1990 at Roswell Park Cancer Institute. STUDY DESIGN: Gastric carcinomas were staged according to the revised 1987 TNM classification. Lymph node dissections were defined according to the General Rules of the Japanese Research Society for Gastric Cancer. Gastric resections in this study were classified as D2.5, D2, D1.5, and D1 and divided into two groups, the extended resection group (D2, D2.5) and the limited resection group (D1, D1.5). RESULTS: The median follow-up period was 33 months. The entire group (n = 101) had an estimated five-year survival rate of 36 percent with a median survival rate of 33 months. The estimated five-year survival rate for the extended resection group (n = 46) was 49 percent with a median of 50 months compared with 27 percent and 25.7 months, respectively, for the limited resection group (n = 55, p = 0.01). Following extended resection, 74 percent of patients with stage I gastric carcinoma survived five years, 75 percent of patients with stage II carcinoma were alive at five years as were 13 percent with stage IIIA, and 30 percent with stage IIIB. Patients whose tumors fell into the classifications of T2-4, N0-1, M0 and required a total or proximal gastrectomy enjoyed a significant survival advantage undergoing an extended resection, with 44 percent surviving five years with a median of 43 months compared with 16 percent and 25 months, respectively, for patients undergoing a limited resection (p = 0.05). Of 13 patients treated with a D2 or greater resection whose gastric carcinomas metastasized to N2 lymph nodes, four patients (31 percent) survived at least five years. Only the extent of lymph node dissection and type of gastric resection proved to be significant independent predictors of overall survival. CONCLUSIONS: Patients treated by extended resection (D2, D2.5) were more likely to survive five years and had prolonged median survival times when compared with patients treated with limited resection (D1, D1.5). For patients with T2-4, N0-1, M0 gastric carcinomas treated with extended resection, their differences reached levels at or approaching statistical significance.

Adenocarcinoma↗