Abundant folate in Zimbabwean beer.
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Beer↗
Biomedical subjects
D G Savage
Publications and source records attributed to D G Savage.
Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies.
PURPOSE: Patients with cobalamin (vitamin B12) deficiency usually lack many of the classic features of severe megaloblastic anemia; because of the low diagnostic specificity of decreased serum cobalamin levels, demonstrating the deficiency unequivocally is often difficult. We examined the sensitivity of measuring serum concentrations of methylmalonic acid and total homocysteine for diagnosing patients with clear-cut cobalamin deficiency and compared the results with those of patients with clear-cut folate deficiency. PATIENTS AND METHODS: Serum metabolites were measured for all patients seen from 1982 to 1989 at two university hospitals who met the criteria for cobalamin and folate deficiency states and for such patients seen from 1968 to 1981 from whom stored sera were available. In all, 406 patients had 434 episodes of cobalamin deficiency and 119 patients had 123 episodes of folate deficiency. Criteria for deficiency states included serum vitamin levels, hematologic and neurologic findings, and responses to therapy. Responses were documented in 97% of cobalamin-deficient patients and 76% of folate-deficient patients. Metabolite levels were measured by modified techniques using capillary-gas chromatography and mass spectrometry. RESULTS: Most of the cobalamin-deficient patients had underlying pernicious anemia; two thirds were blacks or Latinos. Hematocrits were normal in 28% and mean cell volumes in 17%. Of the 434 episodes of cobalamin deficiency, 98.4% of serum methylmalonic acid levels and 95.9% of serum homocysteine levels were elevated (greater than 3 standard deviations above the mean in normal subjects). Only one patient had normal levels of both metabolites. Serum homocysteine levels were increased in 91% of the 123 episodes of folate deficiency. Methylmalonic acid was elevated in 12.2% of the folate-deficient patients; in all but one, the elevation was attributable to renal insufficiency or hypovolemia. CONCLUSIONS: For the cobalamin-deficient patients, measuring serum metabolite concentrations proved to be a highly sensitive test of deficiency. We conclude that normal levels of both methylmalonic acid and total homocysteine rule out clinically significant cobalamin deficiency with virtual certainty.
Female↗
Approaches to the treatment of chronic myeloid leukemia.
In the past two decades there have been a number of advances in the treatment of chronic myeloid leukemia (CML) in chronic phase. There has been very little progress in the management of advanced disease. Hydroxyurea and interferon-alpha have replaced busulfan as first-line therapy in chronic phase. Hydroxyurea provides excellent control of the disease for periods of months or years and has little toxicity. Interferon-alpha induces a reduction in the Philadelphia chromosome in a substantial minority of patients. Interferon-alpha may also prolong survival. Neither hydroxyurea nor interferon-alpha is able to cure the disease. Patients in chronic phase may be cured by allogeneic bone marrow transplantation (BMT). This procedure has a number of limitations, however, including limited availability, high cost, and substantial morbidity and mortality. Current challenges in BMT are to increase its applicability, to reduce graft-versus-host disease, and to augment graft-versus-leukemia effects. The role of autologous transplantation in CML remains speculative.
Bone Marrow Transplantation↗
Elevation of serum cystathionine levels in patients with cobalamin and folate deficiency.
Homocysteine can be methylated to form methionine by the cobalamin- (Cbl) and folate-dependent enzyme, methionine synthase; serum levels of total homocysteine are elevated in greater than 95% of patients with either Cbl or folate deficiency. Homocysteine can also condense with serine to form cystathionine in a pyridoxal phosphate-dependent reaction catalyzed by cystathionine beta-synthase. Cystathionine is subsequently cleaved to cysteine and alpha-ketobutyrate by the pyridoxal phosphate-dependent enzyme gamma-cystathionase. To assess levels of cystathionine in Cbl and folate deficiency, we developed a new capillary gas chromatographic-mass spectrometric assay and measured cystathionine in the serum of normal subjects and patients with clinically confirmed deficiencies of these vitamins. The normal range for serum cystathionine was 65 to 301 nmol/L (median = 126 nmol/L) for 50 normal blood donors. In 30 patients with clinically confirmed Cbl deficiency, values for cystathionine ranged from 208 nmol/L to 2,920 nmol/L (median = 816 nmol/L) and 26 (87%) had levels above the normal range. In 20 patients with clinically confirmed folate deficiency, cystathionine concentrations ranged from 138 nmol/L to 4,150 nmol/L (median = 1,560 nmol/L) and 19 (95%) had values above the normal range. Five homozygotes for cystathionine beta-synthase deficiency had high values for serum-total homocysteine and low or low-normal values for serum cystathionine that ranged from 30 nmol/L to 114 nmol/L even though they were on treatment with pyridoxine and had partially responded. One patient with a defect in the synthesis of 5-CH3-tetrahydrofolate and five patients with defects in the synthesis of CH3-Cbl had high values for serum-total homocysteine and high values for cystathionine that ranged from 311 nmol/L to 1,500 nmol/L even though they were on treatment with folic acid and Cbl, respectively, and had partially responded. We conclude that levels of cystathionine are evaluated in the serum of most patients with Cbl and folate deficiency and that they are useful in the differential diagnosis of an elevated serum-total homocysteine level.
Animals↗
Elevation of 2-methylcitric acid I and II levels in serum, urine, and cerebrospinal fluid of patients with cobalamin deficiency.
Citrate synthase catalyzes the condensation of acetyl-coenzyme A (CoA) and oxaloacetic acid to form citric acid. The enzyme also catalyzes the condensation of propionyl-CoA and oxaloacetic acid with a maximal reaction velocity (Vmax) approximately 10(-4) times that of acetyl-CoA to form 2-methylcitric acid, which contains two asymmetric carbon atoms and exists as two pairs of related enantiomers designated as 2-methylcitric acid I and II. Cobalamin (Cbl) deficiency can lead to increases in intracellular levels of propionyl-CoA. To assess the magnitude of increased synthesis of 2-methylcitric acid in Cbl deficiency, we developed a new capillary gas chromatographic-mass spectrometric assay and measured 2-methylcitric acid levels in serum and cerebrospinal fluid (CSF) of normal subjects and patients with clinically confirmed Cbl deficiency. The normal range for 2-methylcitric acid level was 60 to 228 nmol/L for serum in 50 normal blood donors and 323 to 1,070 nmol/L for CSF in 19 normal subjects. In 50 patients with clinically confirmed Cbl deficiency, values for 2-methylcitric acid in serum ranged from 93 to 13,500 nmol/L; 44 (88%) had values above the normal range. In five patients with clinically confirmed Cbl deficiency, levels of the sum of 2-methylcitric acid I and II ranged from 1,370 to 16,300 nmol/L in CSF, and all five (100%) patients had levels above the normal range. We conclude that levels of 2-methylcitric acid are elevated in serum and CSF of most patients with Cbl deficiency.
Adolescent↗
Metabolic abnormalities in cobalamin (vitamin B12) and folate deficiency.
Mammalian cells contain two Cbl-dependent enzymes, L-methylmalonyl-CoA mutase and methionine synthase. The former requires adenosyl-Cbl and catalyzes the conversion of L-methylmalonyl-CoA to succinyl-CoA. The latter requires CH3-Cbl and catalyzes the conversion of 5-CH3-tetrahydrofolate and homocysteine to tetrahydrofolate and methionine, respectively. Biochemical abnormalities related to a decrease in the activity of methionine synthase are thought to be responsible for the indistinguishable hematologic abnormalities seen in both Cbl and folate deficiency. The biochemical basis for the neuropsychiatric abnormalities seen in Cbl deficiency, but not in folate deficiency, is not known although hypotheses have been proposed that implicate one or the other of the two Cbl-dependent enzymes. Recent studies have shown that levels of serum methylmalonic acid, 2-methylcitric acids I and II, total homocysteine, and cystathionine are elevated in most patients with Cbl deficiency and that total homocysteine, cystathionine, N,N-dimethylglycine, and N-methylglycine are elevated in most patients with folate deficiency. Analysis of these metabolic abnormalities in various patient groups fails to support hypotheses that either L-methylmalonyl-CoA mutase or methionine synthase alone are responsible for the neuropsychiatric abnormalities. We suggest that they may result from a third, unknown mammalian Cbl-dependent enzyme or from a combined deficiency of both Cbl-dependent enzymes together with an unknown genetic or environmental factor.
5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
New approaches to the diagnosis of cobalamin (Cbl, vitamin B12) deficiency in neuropsychiatric disorders.
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Humans↗
Neurologic aspects of cobalamin deficiency.
We reviewed 153 episodes of cobalamin deficiency involving the nervous system that occurred in 143 patients seen over a recent 17-year period at 2 New York City hospitals. Pernicious anemia was the most common underlying cause of the deficiency. Neurologic complaints, most commonly paresthesias or ataxia, were the first symptoms of Cbl deficiency in most episodes. The median duration of symptoms before diagnosis and treatment with vitamin B12 was 4 months, although long delays in diagnosis occurred in some patients. Diminished vibratory sensation and proprioception in the lower extremities were the most common objective findings. A wide variety of neurologic symptoms and signs were encountered, however, including ataxia, loss of cutaneous sensation, muscle weakness, diminished or hyperactive reflexes, spasticity, urinary or fecal incontinence, orthostatic hypotension, loss of vision, dementia, psychoses, and disturbances of mood. Multiple neurologic syndromes were often seen in a single patient. In 42 (27.4%) of the 153 episodes, the hematocrit was normal, and in 31 (23.0%), the mean corpuscular volume was normal. Neutropenia and thrombocytopenia were unusual even in anemic patients. In nonanemic patients in whom diagnosis was delayed, neurologic progression frequently occurred although the hematocrit remained normal. In 27 episodes, the serum cobalamin concentration was only moderately decreased (in the range of 100-200 pg/ml) and in 2 the serum level was normal. Neurologic impairment, as assessed by a quantitative severity score, was judged to be mild in 99 episodes, moderate in 39 and severe in 15. Severity of neurologic dysfunction before treatment was clearly related to the duration of symptoms prior to diagnosis. In addition, the hematocrit correlated significantly with severity, independent of the longer duration of symptoms in nonanemic patients. Four patients experienced transient neurologic exacerbations soon after beginning treatment with cyanocobalamin, with subsequent recovery. Followup evaluation was adequate to assess the neurologic response to vitamin B12 therapy in 121 episodes. All patients responded, and in 57 (47.1%), recovery was complete, with no remaining symptoms or findings on examination. The severity score was reduced by 50% or greater after treatment in 91% of the episodes. Residual long-term moderate or severe neurologic disability was noted following only 7 (6.3%) episodes. The extent of neurologic involvement after treatment was strongly related to that before therapy as well as to the duration of symptoms. The percent improvement over baseline neurologic status after treatment was inversely related to duration of symptoms and hematocrit. Some evidence of response was always seen during the first 3 months of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)
Adolescent↗
Cerebrospinal fluid methylmalonic acid levels in normal subjects and patients with cobalamin deficiency.
We measured methylmalonic acid, which accumulates in the blood and tissues of patients with cobalamin deficiency, in the CSF of 65 patients using capillary-gas chromatography and mass spectrometry. In 58 control patients, methylmalonic acid concentrations were always higher in CSF than in serum (mean CSF: serum ratio, 2.65; range, 1.17 to 7.78). In contrast, in six patients with elevated serum methylmalonic acid levels due to renal failure, CSF concentrations were normal in five and the CSF: serum ratio was less than one in four. In three patients with neuropsychiatric syndromes due to cobalamin deficiency and one patient with a normal serum cobalamin level who was an abuser of nitrous oxide, CSF concentrations were markedly increased (mean level, 600 times that of controls), out of proportion to those in the serum (mean CSF: serum ratio, 8.38; range, 3.5 to 13.5). The potential usefulness of CSF metabolite levels in the diagnosis of cobalamin deficiency is undetermined.
Adult↗
Clinical spectrum and diagnosis of cobalamin deficiency.
To better estimate how frequently patients with low serum cobalamin (Cbl) levels in current clinical practice are truly deficient in Cbl and to determine the incidence of atypical or nonclassic presentations of Cbl deficiency, we prospectively studied 300 unselected consecutive patients with serum Cbl concentrations less than 200 pg/mL seen at two medical centers over a 2-year period. Baseline hematologic, neuropsychiatric, and biochemical measurements were obtained, followed by a course of parenteral Cbl therapy and reassessment. A response to Cbl therapy was defined as one or more of the following: (1) an increase in hematocrit of 0.05 or more; (2) a decrease in mean cell volume of 5 fL or more; (3) a clearing of hypersegmented neutrophilis and macroovalocytes from the peripheral blood smear; and (4) an unequivocal and prompt improvement of neuropsychiatric abnormalities. Of the 300 patients with serum Cbl levels less than 200 pg/mL, 86 had one or more responses to Cbl therapy and 59 had no response. In 155, insufficient data was available. In the Cbl-responsive patients, normal values were found for the following tests: hematocrit, 44%; mean cell volume less than or equal to 100 fL, 36%; white blood cell count, 84%; platelet count, 79%; serum lactic dehydrogenase, 43%; and serum bilirubin, 83%. Peripheral blood smears were nondiagnostic in 6% when reviewed by the investigators, but 33% as reported by routine laboratories. Serum Cbl levels in the 100 to 199 pg/mL range were present in 38%. Neuropsychiatric abnormalities were noted in 28%, often in the absence of anemia, macrocytosis, or both. Serum levels of methylmalonic acid and/or total homocysteine were elevated greater than 3 SDs above the mean for normal subjects in 94% of the Cbl-responsive patients. We conclude that Cbl deficiency should be considered and investigated in patients with unexplained hematologic or neuropsychiatric abnormalities of the kind seen in Cbl deficiency, even if anemia, an elevated mean cell volume, a marked depression of the serum Cbl, or other classic hematologic or biochemical abnormalities are lacking. Levels of serum methylmalonic acid and total homocysteine are useful as ancillary diagnostic tests in the diagnostis of Cbl deficiency.
Bilirubin↗
Diagnosis of cobalamin deficiency I: usefulness of serum methylmalonic acid and total homocysteine concentrations.
The serum cobalamin assay is the primary diagnostic test for cobalamin deficiency. It appears to be an excellent screening test since most patients with clinically confirmed cobalamin deficiency have low levels. Recent studies indicate that the clinical picture of cobalamin deficiency is much more diverse than previously believed. It is also apparent that many patients with low serum cobalamin concentrations are not cobalamin deficient. Thus, there is a need for additional diagnostic tests to further distinguish patients with low serum cobalamin levels who are actually cobalamin deficient and will benefit from lifetime treatment from those who are not deficient and will not benefit. Serum levels of methylmalonic acid and total homocysteine have been shown to be markedly elevated in most patients with cobalamin deficiency, and total homocysteine concentrations are markedly elevated in most patients with folate deficiency. The levels of these metabolites fall to normal if these patients are treated with the appropriate vitamin but remain essentially unchanged if the wrong vitamin is administered. These observations demonstrate that serum methylmalonic acid and total homocysteine levels are useful in diagnosing patients with cobalamin and folate deficiency and in distinguishing between these two vitamin deficiencies.
Adolescent↗
Diagnosis of cobalamin deficiency: II. Relative sensitivities of serum cobalamin, methylmalonic acid, and total homocysteine concentrations.
The serum cobalamin level has been generally considered to be essentially 100% sensitive in the detection of the clinical disorders caused by cobalamin deficiency. We tested this hypothesis in two groups of patients. In patients with pernicious anemia or previous gastrectomy who received less than monthly maintenance therapy, early hematologic relapse was associated with elevation of the serum methylmalonic acid, total homocysteine, or both metabolites in 95% of instances, although the serum cobalamin was low in only 69%. In the absence of hematologic relapse, the methylmalonic acid was abnormal more than twice as frequently as the serum cobalamin. We also reviewed the records of 419 consecutive patients with recognized clinically significant cobalamin deficiency. Twelve patients were identified in whom deficiency was clearly present although the serum cobalamin was greater than 200 pg/ml. Anemia was usually absent or mild, but 5 had prominent neurological involvement that subsequently responded to cobalamin. Both the serum methylmalonic acid and total homocysteine were increased in each patient. The serum cobalamin was normal in 9 (5.2%) of 173 patients with recognized cobalamin deficiency seen in the last 5 years. Antibiotic treatment lowered the serum methylmalonic acid but not the total homocysteine level in two cobalamin-deficient patients, suggesting that propionic acid generated by the anaerobic gut flora may be a precursor of methylmalonic acid in deficient patients. We conclude that the serum cobalamin is normal in a significant minority of patients with cobalamin deficiency and that the measurement of serum metabolite concentrations facilitates the identification of such patients.
Adult↗
Assessment of an interactive microcomputer-videodisc programme for teaching medical students to evaluate the peripheral blood smear.
An interactive microcomputer-videodisc programme for providing instruction in interpreting the peripheral blood smear was evaluated by 23 medical students. The mean scores of the students on a test of interpretation of photomicrographs of blood smears increased significantly after use of the teaching programme. The students' responses to a questionnaire indicated that they viewed computer based instruction as a useful learning tool. The results of the study suggest that computer assisted instruction may be one method for addressing some of the current problems in medical education.
Blood Cell Count↗
Neuropsychiatric disorders caused by cobalamin deficiency in the absence of anemia or macrocytosis.
Among 141 consecutive patients with neuro-psychiatric abnormalities due to cobalamin deficiency, we found that 40 (28 percent) had no anemia or macrocytosis. The hematocrit was normal in 34, the mean cell volume was normal in 25, and both tests were normal in 19. Characteristic features in such patients included paresthesia, sensory loss, ataxia, dementia, and psychiatric disorders; longstanding neurologic symptoms without anemia; normal white-cell and platelet counts and serum bilirubin and lactate dehydrogenase levels; and markedly elevated serum concentrations of methylmalonic acid and total homocysteine. Serum cobalamin levels were above 150 pmol per liter (200 pg per milliliter) in 2 patients, between 75 and 150 pmol per liter (100 and 200 pg per milliliter) in 16, and below 75 pmol per liter (100 pg per milliliter) in only 22. Except for one patient who died during the first week of treatment, every patient in this group benefited from cobalamin therapy. Responses included improvement in neuropsychiatric abnormalities (39 of 39), improvement (often within the normal range) in one or more hematologic findings (36 of 39), and a decrease of more than 50 percent in levels of serum methylmalonic acid, total homocysteine, or both (31 of 31). We conclude that neuropsychiatric disorders due to cobalamin deficiency occur commonly in the absence of anemia or an elevated mean cell volume and that measurements of serum methylmalonic acid and total homocysteine both before and after treatment are useful in the diagnosis of these patients.
Adolescent↗
Elevation of total homocysteine in the serum of patients with cobalamin or folate deficiency detected by capillary gas chromatography-mass spectrometry.
To determine if levels of serum total homocysteine are elevated in patients with either cobalamin or folate deficiency, we utilized a new capillary gas chromatographic-mass spectrometric technique to measure total homocysteine in the serum of 78 patients with clinically confirmed cobalamin deficiency and 19 patients with clinically confirmed folate deficiency. Values ranged from 11 to 476 mumol/liter in the cobalamin-deficient patients and 77 of the 78 patients had values above the normal range of 7-22 mumol/liter as determined for 50 normal blood donors. In the cobalamin-deficient patients, serum total homocysteine was positively correlated with serum folate, mean corpuscular volume, serum lactate dehydrogenase, serum methylmalonic acid, and the degree of neurologic involvement, and inversely correlated with platelets and hematocrit. In the folate-deficient patients, values for serum total homocysteine ranged from 17 to 185 mumol/liter and 18 of the 19 patients had values above the normal range. Some patients with pernicious anemia who were intermittently treated with cyanocobalamin were found to have elevated serum levels of total homocysteine while they were free of hematologic and neurologic abnormalities. The measurement of serum total homocysteine will help define the incidence of cobalamin deficiency and folate deficiency in various patient populations.
Adult↗
A comparison of computer-assisted instruction and tutorials in hematology and oncology.
In the study reported here, third-year medical students in an internal medicine clerkship were randomly assigned to computer-assisted instruction (CAI) and to tutorials to compare the effectiveness of these methods in teaching hematology and oncology topics. A multiple-choice test was used to assess the students' knowledge after instruction, and the students completed a 14-item questionnaire concerning their opinions of CAI. No statistically significant difference was found between the test scores of the students using CAI and those in the tutorials for oncology; but in hematology the students in the tutorials had higher scores than those using CAI. The study design does not permit a definite explanation of the disparity in outcome for the two topics, but it is possible that the effectiveness of the presentations in the two sections was different. There was no statistically significant correlation between the time spent in the teaching setting and the score attained. The students did not consider CAI more effective than the tutorials but rather seemed to view it as a supplement to traditional teaching by lectures, textbooks, and studying from notes.
Attitude↗
Oncology clinic attendance at an inner city hospital.
Compliance in oncology clinic attendance was prospectively evaluated over a 12-month period at Harlem Hospital Center, an inner city municipal facility serving a predominantly black population. One hundred patients were followed (97 blacks, 2 Hispanics, 1 white) with an average age of 60 years. There were 41 men and 59 women. Thirty-one patients had breast cancer, 23 lung cancer, 26 miscellaneous solid tumors, and 20 hematologic malignancies. Forty-two patients received chemotherapy, 14 hormonal therapy, and 44 supportive care alone. Of the 657 appointments scheduled for the total group, 583 (89%) were kept. All scheduled appointments were kept by 53% of patients and 80% or more were kept by 69% of patients. There was no statistically significant difference in clinic attendance according to sex, age younger than 50 years, tumor category, or mode of therapy. Reasons for missing appointments included the patient forgot or was confused (7 cases), weather (5), transportation difficulties (5), clerical error (3), and refusal of further chemotherapy (1). A high rate of clinic attendance is reported in this group of patients with multiple social and financial problems. Such patients are appropriate candidates for treatment protocols requiring frequent clinic visits.
Black or African American↗
Biphasic pattern of bacterial infection in multiple myeloma.
Since the 1960s, gram-negative bacilli have become commoner pathogens than Streptococcus pneumoniae in multiple myeloma. To investigate this trend, we analyzed 75 bacterial infections in 57 patients with myeloma. Episodes of infection with Streptococcus pneumoniae and Haemophilus influenzae occurred at presentation, early in the disease, and in patients responding to chemotherapy. Gram-negative bacilli and Staphylococcus aureus caused 80% of infections seen after diagnosis and 92% of deaths from infection. Episodes of infection with gram-negative bacteria occurred in patients with active and advancing disease and in those responding to chemotherapy when neutropenia. Impaired antibody production may be the major immune defect leading to S. pneumoniae and H. influenzae infections whereas some additional factor or factors related to disease activity appear to predispose to gram-negative infection in myeloma.
Aged↗