Search PubMed⌕ Search

Biomedical subjects

M S Oh

Publications and source records attributed to M S Oh.

At least 37 records · Page 2Linked to original sources
PubMed1995

A re-evaluation of the urinary parameters of acid production and excretion in patients with chronic renal acidosis.

We have studied acid-base balance in 32 patients attending the renal clinic of Mount Sinai Hospital. The parameters of acid-base balance measured included acid production measured as urinary sulfate and organic anions, net acid excretion measured as urinary ammonia plus titratable acid minus bicarbonate, and net GI absorption of alkali measured by a new method utilizing urinary electrolytes. Net GI absorption of alkali by urinary electrolytes measures alkali addition to the body from the GI tract as well as from any other sources, including bone. All patients had a creatinine clearance less than 80 ml/min and they were divided into two groups: those with normal serum bicarbonate (Group 1; N = 12) and those with subnormal serum bicarbonate (Group 2; N = 20). Hydrogen ion balance was -0.6 +/- 9 mEq/day in the first group, while those in the second group had a hydrogen ion balance of +16 +/- 5 mEq/day. A group of 8 normal controls had a hydrogen ion balance of -0.3 +/- 5 mEq/day. When the sum of all cations was compared with the sum of all anions in the urine, a cation gap of exactly the same magnitude as the positive hydrogen ion balance was found in patients with low serum bicarbonate. In conclusion, our data show that patients with decreased GFR and low serum bicarbonate appear to have a significantly positive hydrogen ion balance. However, we believe that the positive hydrogen ion balance is only apparent, but not real for the following reasons.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1995

The effect of pass/fail grading and weekly quizzes on first-year students' performances and satisfaction.

BACKGROUND: In 1992-93 the University of Michigan Medical School revised its first-year curriculum. An evaluation system using honors, high-pass, pass, and fail grading and only two examinations (a midterm and a final) was replaced with a system using pass/fail grading and weekly quizzes in addition to the two examinations. The objective was to increase students' satisfaction while maintaining a high level of achievement. METHOD: Students' performance scores and survey data from the final year of the former system (1991-92, 222 students) and the first year of the new system (1992-93, 195 students) were used to investigate whether overall performance decreased and whether the students liked the new approach to grading. Statistical methods used were one-sample t-tests, Student's t-test, and Fisher's Z-test. RESULTS: Under the new system, the average scores for courses remained well above passing, and no evidence was found that the students achieved at lower levels than had their predecessors with the former, more traditional grading system. Also, higher cumulative pre-final scores (i.e., scores on the weekly quizzes as well as the midterm) did not predict lower, "just passing" achievement on final examinations. The students' responses to the surveys included comments that pass/fail grading eased anxiety and reduced competition while encouraging the students' co-operation. CONCLUSION: Despite concerns that implementing pass/fail grading for all first-year courses would result in lower overall performance and decreased motivation among students, during the first year of implementation these fears proved to be unfounded as the students continued to perform well and reported greater satisfaction with the new system.

Attitude↗
PubMed1994

Renal stone risk factors in patients with type IV renal tubular acidosis.

Renal stone formation is uncommon in patients with type IV renal tubular acidosis (RTA). This study was undertaken to explore the urinary biochemical and physicochemical factors in patients with type IV RTA in order to elucidate the mechanisms that protect them from renal stone formation. Twelve subjects with type IV RTA and 12 matched subjects with a similar degree of kidney impairment but without RTA were studied. Both groups of patients had low urinary excretion of calcium, phosphorus, uric acid, and citrate, probably reflective of kidney impairment. Patients with type IV RTA had a significantly lower urinary pH and urinary excretion of calcium than their matched controls. Hypocitraturia was present in both groups without any significant difference between them. This study suggests that the major protection from renal stone formation in type IV RTA results from impaired renal function and ensuing reduction in renal excretion of stone-forming substances, such as calcium and uric acid.

Acidosis, Renal Tubular↗
PubMed1994

Influence of a highly focused case on the effect of small-group facilitators' content expertise on students' learning and satisfaction.

BACKGROUND: There has been considerable debate over the need for content expertise to lead a successful small-group discussion for medical students. Some authors feel process expertise related to the conduct of a small group is of more value than content expertise related to the case. At least one study has presented data that suggest content expertise can lead to teacher domination of the learning environment. In an earlier study, the present authors found that students learned more and were more satisfied with small-group instruction when the instruction was facilitated by a faculty member who was an expert in the content of the case. That study also identified no tendency for content experts to dominate the sessions (e.g., through lecturing or otherwise controlling the learning environment). The purpose of the present study was to explore the efficacy of a carefully designed and highly focused case problem to remove the influence of group facilitators' content expertise on students' learning outcomes. METHOD: The 211 students in the University of Michigan Medical School class of 1994 were randomly assigned to 28 groups in a microbiology and immunology course in the fall of 1991; each small group was led by a faculty facilitator. Complete data were available from 27 groups: 13 groups led by experts and 14 groups led by non-experts. Data collection included observers' codings of interactions between the students and the facilitators (interactional analysis), test scores, and students' ratings of the experience. RESULTS: Unlike in the previous study, group leaders who were content experts devoted significantly more time to teacher-directed activities than did non-content-expert leaders. However, overall, 62% of the time was devoted to student-initiated activity. The results of the multiple-choice tests that were related specifically to the goals of the case indicated there was no significant difference between the students' performances in the groups led by experts and those led by non-experts. With respect to students' satisfaction, all students gave consistently high ratings to the experience and there was no difference between groups led by expert and non-expert facilitators. CONCLUSION: The data from this study suggest that a facilitator's content expertise alone does not determine the amount of teacher-directed behavior in a group, the amount of students' learning, or students' satisfaction. The focus built into the case and the amount of facilitator's training directly related to the content of the case are also significant variables related to students' learning, teacher's behavior, and students' satisfaction.

Curriculum↗
PubMed1993

Medical student use of history and physical information in diagnostic reasoning.

Clinical data gathering is central to clinical competence. Although research has demonstrated the value to experienced clinicians of information obtained from the history, little is known of how medical students use this information. In the present study, two case simulations (in rheumatoid arthritis and systemic lupus erythematosis) were developed to assess medical student information gathering and utilization. The results indicate that most of the students were already considering the correct diagnosis as a possibility after the presenting complaint and patient description. However, the medical history exerted the strongest influence on transforming the correct diagnosis from just another diagnostic possibility into the favored diagnostic candidate. Students who failed to list the correct diagnosis in the differential diagnosis after obtaining the history were significantly less likely to reach the correct diagnosis at the end of the case. These results confirm the critical importance of the history in medical problem solving.

Arthritis, Rheumatoid↗
PubMed1993

Alkali absorption and citrate excretion in calcium nephrolithiasis.

The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p < 0.001). In 11 patients with distal renal tubular acidosis (RTA), urinary citrate excretion was subnormal relative to net GI alkali absorption, with data from most patients residing outside the 95% confidence ellipse described for normal subjects. However, the normal relationship between urinary citrate and net absorbed alkali was maintained in 11 patients with chronic diarrheal syndrome (CDS) and in 124 stone-forming patients devoid of RTA or CDS, half of whom had "idiopathic" hypocitraturia. The 18 stone-forming patients without RTA or CDS received potassium citrate (30-60 mEq/day). Both urinary citrate and net GI alkali absorption increased, yielding a significantly positive correlation (r = 0.62, p < 0.0001), with the slope indistinguishable from that of normal subjects. Thus, urinary citrate was normally dependent on the net GI absorption of alkali. This dependence was less marked in RTA, confirming the renal origin of hypocitraturia. However, the normal dependence was maintained in CDS and in idiopathic hypocitraturia, suggesting that reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

Acidosis, Renal Tubular↗
PubMed1993

A comparison of the diabetes-related attitudes of health care professionals and patients.

The following study compares the diabetes-related attitudes of sampled health care professionals and patients with diabetes. Attitudes were measured with a revised version of the Diabetes Attitude Scale (DAS) which includes seven factors representing attitudes towards: (1) the need for special training in order to provide diabetes care; (2) patient compliance; (3) the seriousness of noninsulin-dependent diabetes (NIDDM); (4) the relationship between blood glucose levels and the complications of diabetes; (5) the impact of diabetes on the patient's life; (6) patient autonomy; and (7) team care. The highest levels of agreement among patients and professionals concerned the seriousness of NIDDM and the relationship between blood glucose control and the development of the complications of diabetes. The most striking finding of the study was that patients tended to express a significantly more judgmental, moralistic attitude toward patient behavior than did health care professionals.

Attitude of Health Personnel↗
PubMed1993

Renal hypouricemia and absorptive hypercalciuria: a real syndrome.

We describe a case of renal hypouricemia due to increased tubular secretion of urate associated with absorptive hypercalciuria. This association has been described in the past, but this is the first time that high plasma levels of 1,25-dihydroxyvitamin D have been reported. A possible cause-and-effect relation between altered uric acid transport and altered vitamin D metabolism in the proximal tubule is suggested.

Adult↗
PubMed1992

Effects of expert and non-expert facilitators on the small-group process and on student performance.

At the University of Michigan Medical School in 1990, the authors investigated the effects of faculty facilitators' levels of content expertise on the educational process and learning outcomes of small-group teaching sessions. The study was conducted in a microbiology course for second-year students in which four small-group sessions were used to replace 38 hours of lecture and laboratory time. The interactions between 11 expert and ten non-expert faculty facilitators and 156 students were observed and coded. The students' levels of knowledge and satisfaction were measured. The results indicate that, although significant differences in faculty-student interactions were not observed, the students in the 11 groups led by the content experts had higher levels of satisfaction and higher examination scores.

Attitude↗
PubMed1992

Disorders of sodium metabolism: hypernatremia and hyponatremia.

OBJECTIVE: Discussion of abnormal plasma sodium concentrations with an emphasis on the pathogenesis, diagnosis, and treatment. DATA SOURCES: Relevant literature in the English language and the authors' clinical experience. STUDY SELECTION: No special study has been carried out for the present discussion. DATA EXTRACTION: The information from the literature and the data from the authors' clinical experience have been used to illustrate important points in the discussion. DATA SYNTHESIS: A most important aspect in the approach to hypernatremia is determination of the mechanism responsible for impaired water intake. Various mechanisms of abnormal water loss can be determined from measurement of urine osmolality. Hypernatremia is treated by water replacement and measures to reduce abnormal water loss. In most instances, hyponatremia is caused by inappropriate concentration of urine because of either appropriate or inappropriate antidiuretic hormone secretion. The determination of appropriateness of antidiuretic hormone secretion requires the assessment of effective arterial volume. Treatment depends on the pathogenetic mechanism. CONCLUSIONS: Abnormal plasma sodium concentration results from abnormal water intake or water output. Treatment is guided by determining the pathogenetic mechanism.

Diagnosis, Differential↗
PubMed1991

Effect of meal on the physiological and physicochemical actions of potassium citrate.

The effect of meals on the physiological and physicochemical actions of potassium citrate was examined in 8 patients with nephrolithiasis maintained on a constant metabolic dietary regimen. Potassium citrate (20 mEq. 3 times per day), whether given with food or on an empty stomach, significantly increased urinary pH, citrate and potassium, and decreased urinary calcium and ammonium. Moreover, potassium citrate decreased urinary saturation of calcium oxalate and uric acid, although it slightly increased that of brushite. However, there was no significant difference in these measures when the drug was given with meals from the time when it was given on an empty stomach. Thus, the effect of potassium citrate on urinary risk factors is unaffected by food.

Adult↗