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Biomedical subjects

M J Wolin

Publications and source records attributed to M J Wolin.

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

Bioconversion of Cellulose to Acetate with Pure Cultures of Ruminococcus albus and a Hydrogen-Using Acetogen.

Bioconversion of cellulose to acetate was accomplished with cocultures of two organisms. One was the cellulolytic species Ruminococcus albus. It ferments crystalline cellulose (Avicel) to acetate, ethanol, CO(inf2), and H(inf2). The other organism (HA) obtains energy for growth by using H(inf2) to reduce CO(inf2) to acetate. HA is a gram-negative coccobacillus that was isolated from horse feces. Coculture of R. albus with HA in batch or continuous culture alters the fermentation products formed from crystalline cellulose by the ruminococcus via interspecies H(inf2) transfer. The major product of the fermentation by R. albus and HA coculture is acetate. High concentrations of acetate (333 mM) were obtained when batch cocultures grown on 5% cellulose were neutralized with Ca(OH)(inf2). Continuous cocultures grown at retention times of 2 and 3.1 days produced 109 and 102 mM acetate, respectively, when fed 1% cellulose with utilization of 84% of the substrate.

Journal Article↗
PubMed1994

Serum stem cell factor levels in patients with aplastic anemia.

Immune suppression of hematopoiesis has been implicated in the pathogenesis of acquired aplastic anemia. Similarly, abnormalities of T cells and bone marrow stromal cells have been reported in aplastic anemia, as has abnormal cytokine production. Stem cell factor (SCF) (also known as kit ligand, mast cell growth factor and Steel factor) is an early acting hematopoietic growth factor that is produced by a variety of mesenchymal cells including bone marrow stromal cells. To determine whether abnormalities in the production of stem cell factor occur in aplastic anemia, we evaluated serum levels of SCF in 25 patients with aplastic anemia. The mean serum levels of SCF in aplastic anemia patients were significantly lower (2.7 +/- 1.1 ng/ml) than those found in a comparable population of 257 normal controls (3.3 +/- 1.1 ng/ml) (P = 0.011). The SCF level did not correlate with patient age, the duration of aplastic anemia or with white blood cell count, platelet count or hematocrit. Although there is no direct evidence that lower SCF serum levels contribute to the pancytopenia seen in this disorder, identification of underlying abnormalities that can result in the deficient production of stromally derived hematopoietic growth factors will be important.

Adolescent↗
PubMed1994

Alzheimer's disease and the eye.

AD patients may have substantial defects in the visual system despite a normal routine eye exam. Specific methods should be utilized to assess the ability of these patients to understand what they see and read. Subtle defects of eye movements may be present. Problems with contrast sensitivity, color vision, and stereo vision may be also be present, as well as early signs of optic atrophy. An awareness of the specific problems that AD patients present will lead the clinician to accurate diagnosis.

Alzheimer Disease↗
PubMed1993

Bacterial strains from human feces that reduce CO2 to acetic acid.

We used dilutions of fecal suspensions from a human volunteer to enrich cultures for bacteria that reduce CO2 to acetate in the colon. The soluble enrichment substrates used were glucose, methanol, formate, and vanillate, which were used with a gas phase that contained 80% N2 and 20% CO2. The gaseous enrichment substrates used were 80% H2-20% CO2 and 50% CO-50% CO2. We isolated three different strains that produced acetate from CO2. One strain produced acetate from methanol, vanillate, H2-CO2, glucose, and other sugars. The other two strains did not form acetate from methanol or vanillate. Both of the latter strains formed acetate from glucose and other sugars, but only one of these strains formed acetate from H2-CO2. Both of these strains cometabolized formate. However, none of the enrichment cultures or pure cultures used CO or formate as a substrate for growth. The two strains that produced acetate from H2 and CO2 grew slowly when the gases alone were used as substrates, but they rapidly cometabolized H2 and CO2 when they were grown with organic substrates. The ability of all of the strains to produce acetate from CO2 and/or other one-carbon precursors was verified by determining the radioactivity of the methyl and carboxyl groups of the acetate formed after growth with 14CO2 or other radioactively labeled one-carbon precursors.

Acetates↗
PubMed1993

Amounts of viable anaerobes, methanogens, and bacterial fermentation products in feces of rats fed high-fiber or fiber-free diets.

We investigated the impact of dietary fiber on the fecal output of microorganisms and microbial fermentation products of rats. Two groups of five male Wistar rats were fed high-fiber (HF) and fiber-free (FF) diets in the following order: (group 1) lab chow-->HF-->FF-->HF and (group 2) lab chow-->FF-->HF-->FF. Daily fecal output of total viable anaerobes was 71 times higher with the HF diet. Daily output of methanogens was 1.4 times higher for the HF diet than for the FF diet. Daily excretion of total fermentation acid products (acetate, propionate, butyrate, lactate, succinate, and formate) was 2.4 and 0.1 mmol for HF and FF diets, respectively. The ratios of acetate/propionate/butyrate were 69:21:10 for the HF diet and 92:7:1 for the FF diet. The results show that an HF diet significantly increases microbial growth in the colon and influences the proportions of organic acid products. The HF diet did not increase the ratio of methanogens to total anaerobes. We suggest that the contribution of host-derived substrates to colonic microbial growth and fermentation is insignificant.

Animals↗
PubMed1993

Calcified brain metastasis.

Two patients with rare cases of calcified brain metastases are reported. The relatively benign clinical course and prolonged survival are stressed. The first patient had an adenocarcinoma of unknown origin with three calcified brain metastases. The patient underwent an incisional brain biopsy without radiotherapy and survived for 2 years and 9 months. The second patient had a squamous cell carcinoma of the lung with a large, solitary brain metastasis. The brain tumor was calcified and remained stable without progression for at least 4 months before surgical resection.

Adenocarcinoma↗
PubMed1992

Cornstarch fermentation by the colonic microbial community yields more butyrate than does cabbage fiber fermentation; cornstarch fermentation rates correlate negatively with methanogenesis.

Fermentations of cornstarch and a cabbage-fiber preparation by human fecal suspensions were studied. The molar percent of butyrate of total short-chain fatty acid products was significantly higher when cornstarch was the substrate. Higher molar percents of butyrate were also produced from cornstarch as compared with endogenous substrate when rat fecal suspensions were used. A range of cornstarch fermentation rates was found with suspensions from 20 human subjects. Rapid fermentaion was associated with the absence of methane production. Methane-negative rat fecal suspensions also fermented cornstarch more rapidly than did methane-positive suspensions. High butyrate production may be important because butyrate provides energy to colonocytes and it regulates differentiation of cultured cells.

Analysis of Variance↗
PubMed1992

Aneurysmal oculomotor nerve palsy in an 11-year-old boy.

Cerebral aneurysms are rare in children. When they occur, they usually present with a history of subarachnoid hemorrhage. Gabianelli et al. (1) recently reported a 14-year-old girl with an isolated oculomotor nerve palsy due to aneurysm. In their discussion, they state that arteriography is, "Unnecessary in patients under 10 (years of age) if the symptoms and signs of subarachnoid hemorrhage are absent or high resolution computerized tomography scan or adequate magnetic resonance imaging scan is normal." To date, their patient is the youngest reported in the literature with an isolated oculomotor nerve palsy proved to be caused by cerebral aneurysm. We report herein an 11-year-old boy who presented with an oculomotor nerve palsy due to aneurysm with minimal preceding symptoms and no other signs of intracranial disease.

Carotid Artery Diseases↗
PubMed1990

Spontaneous visual recovery from traumatic optic neuropathy after blunt head injury.

Four patients who developed immediate blindness (no light perception) after indirect traumatic optic neuropathy caused by blunt head injury recovered vision without surgical intervention. In one patient, whose affected eye recovered to a visual acuity of 20/50 + 2, corticosteroids were not used. In two of the other patients, visual recovery began before corticosteroids were instituted. One patient recovered a visual acuity of R.E.: 20/15, one recovered a visual acuity of L.E.: 20/25-2, and one recovered a visual acuity of R.E.: 20/200 but with useful temporal field vision. Many investigators advocate aggressive surgical therapy for indirect neuropathy, particularly when corticosteroids fail. Significant recovery may occur despite no light perception, however, with medical therapy or even without therapy.

Adolescent↗
PubMed1990

Characterization of carbohydrate fermentation in feces of formula-fed and breast-fed infants.

We wished to characterize the carbohydrate fermentation by intestinal flora in formula-fed infants and in breast-fed infants. We also wished to compare the carbohydrate fermentation process in the two groups to determine whether differences that existed between groups could help explain the observation that breast-fed infants usually have milder forms of acute gastroenteritis. We performed in vitro incubations of fecal samples from nine formula-fed and 14 breast-fed infants and examined the samples for fermentation characteristics, the effect of acid pH on bacterial fermentation, and changes in carbohydrate fermentation in relation to the age of the infant. Fecal samples were incubated, with and without the addition of lactose, at a pH of 6.8 and at a pH of 5.5. Volatile fatty acids and carbohydrates were determined in the incubates. The addition of lactose to the incubate at pH 6.8 resulted in significantly increased volatile fatty acid production and larger amounts of lactose, glucose, and galactose compared with the values observed in 1-h incubates to which no lactose was added. At pH 5.5, volatile fatty acid production was significantly lower in both groups compared with that at pH 6.8, and the accumulation of monosaccharides in the incubate of feces of formula-fed infants increased significantly (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Feeding↗
PubMed1990

Mucinous adenocarcinoma of the orbit arising from a stable, benign-appearing eyelid nodule.

Mucinous adenocarcinoma is a rare eyelid tumor which should be considered in the differential diagnosis of a nodular or cystic lesion of the eyelid. This lesion may be locally aggressive and requires complete excision to prevent local recurrence or regional metastases. We present what we believe is the first report of a mucinous adenocarcinoma manifesting as a stable, benign-appearing nodule that has already given rise to a much larger secondary lesion. This case underscores the importance of performing a biopsy on even benign-appearing eyelid nodules.

Adenocarcinoma, Mucinous↗
PubMed1990

Multiple orbital tumors were cavernous hemangiomas.

Two distinct masses in the left orbit were incidentally found in a 48-year-old woman during a computed tomographic scan done to evaluate neurologic complaints. Initial diagnostic considerations focused on a lymphoproliferative disorder or other systemic disease. Orbitotomy revealed two discrete tumors, both cavernous hemangiomas. Although uncommon, cavernous hemangioma should be considered in the differential diagnosis of the patient with multiple orbital lesions.

Female↗
PubMed1989

Increase in colonic methanogens and total anaerobes in aging rats.

Methanogens are present in the colons of our local Wistar rat colony. We studied the changes in concentrations of their fecal methanogenic and nonmethanogenic bacteria with age as a model of the development of these communities in humans. We found that the predominant methanogen in the rats is a Methanobrevibacter species. The log of the concentration of total anaerobes increased from 9.8/g (dry weight) at 3.0 weeks of age (shortly after weaning) to 10.7/g (dry weight) at 96 weeks (shortly before the end of the life span). In contrast, the log concentration of methanogens increased from 5.5 to 9/g (dry weight) during the same time period. Therefore, methanogens increased as a percentage of the total anaerobes from 0.005% at 3.0 weeks to 2.0% at 96 weeks. About 12 doublings of the methanogenic population and 3.3 doublings of the nonmethanogenic population took place from weaning until death. The slow increase in the ratio of methanogens to total anaerobes with age followed the same pattern in cecal contents as found in feces. There were no relationships between animal weights or fecal outputs and the increase in total anaerobe and methanogen concentrations in feces. A possible explanation for the slow increase in the Methanobrevibacter species in Wistar rats with age is a gradual shifting of the use of electrons from the reduction of CO2 to acetate by acetogens to the reduction of CO2 to CH4. The results provide the first evidence for an age-related change in the nonmethanogenic bacteria of the colon and supporting microbiological evidence for physiological studies that have shown age-related increases in colonic methane production in humans.

Aging↗
PubMed1989

Constancy of glucose and starch fermentations by two different human faecal microbial communities.

The fermentation of glucose and corn starch by faecal suspensions from two subjects was examined over a three and a half year period. The substrate specificity and products of the faecal fermentations of each subject were relatively stable during this period and were significantly different between subjects. The major soluble end products of fermentation of glucose or starch were acetate, propionate, and butyrate. Hydrogen temporarily accumulated and was subsequently used in fermentations by both subjects. Hydrogen was used without methane production in fermentations of subject 1, but was used for methane formation in fermentations of subject 2. Although the rates of glucose fermentation were similar between both subjects; subject 1 produced a significantly greater molar ratio of propionate than did subject 2. The rate of fermentation of starch by faecal suspensions from subject 1 was faster than that of subject 2. The molar ratio of butyrate was greater for starch fermentations by subject 2, while the molar ratio of propionate was greater with subject 1. Significant differences were found between subjects in molar ratios and concentration of acetate and propionate and concentrations of butyrate in faeces.

Acetates↗
PubMed1989

Dacryocystectomy for the treatment of dacryocystitis patients with Wegener's granulomatosis.

We evaluated a woman with Wegener's granulomatosis who was experiencing recurrent dacryocystitis. Nasolacrimal duct obstruction had been present for many years and epiphora was not a significant concern. Our experience with the development of nasalcutaneous fistulas following dacryocystorhinostomy in several patients with Wegner's granulomatosis led us to perform a dacryocystectomy. The functional result was good, and there were no problems with wound healing. Dacryocystectomy should be considered as an alternative to dacryocystorhinostomy for dacryocystitis in patients with Wegener's granulomatosis and similar disorders in whom epiphora is not a major complaint.

Adult↗