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Biomedical subjects

M B Hall

Publications and source records attributed to M B Hall.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differences in yields of microbial crude protein from in vitro fermentation of carbohydrates.

The yield of microbial crude protein (CP) from carbohydrate fermentations was examined using trichloroacetic acid (TCA) precipitation of batch cultures. The medium contained ammonium bicarbonate, casein acid hydrolysate, and cysteine hydrochloride as nitrogen sources. Isolated bermudagrass neutral detergent fiber (iNDF) and 60:40 blends of iNDF and sucrose (Suc), citrus pectin (Pec), or corn starch (Sta) (approximately 375 mg of substrate organic matter/vial) were fermented in vitro in two separate fermentation runs with mixed ruminal microbes. Three fermentation tubes for each substrate were destructively sampled at 0, 4, 8, 12, 16, 20, and 24 h. Fermented samples were precipitated at a concentration of 19.4% TCA, and filtered to collect unfermented iNDF and precipitate. Collected residues were analyzed for CP as Kjeldahl N x 6.25. Microbial CP (TCACP) was estimated as TCA-precipitated CP corrected for the TCA-precipitated CP content of substrates at 0 h, and the mean of fermentation blanks from each hour. Medium pH did not decline below 6.49 in any fermentation tube. Comparisons of maximal yields based on the hour in which the measured mean yield was greatest for each substrate in each fermentation indicated that Sta > Suc = Pec > iNDF (P < 0.05). All substrates showed increases in TCACP to their maxima, followed by declines in TCACP. This likely reflects the relative dominance of production or degradation of microbes about the point of substrate limitation. Unlike other substrates, Suc had no detectable lag, and presented a more persistent TCACP yield curve than the other non-NDF carbohydrates (NFC). Regression analysis of TCACP yield over time for iNDF versus other substrates, Pec + Sta versus Suc, and Pec versus Sta indicated that the compared curves were not parallel (P < 0.05). The patterns of TCACP yield over time were cubic for iNDF and Suc, and quartic for Pec and Sta. The maximal yields of TCACP predicted from the regressions were Sta: 34.0 mg at 15.6 h, Pec: 29.9 mg at 13.5 h, Suc: 25.5 mg at 12.6 h, and iNDF: 13.6 mg at 19.3 h. The NDF and NFC carbohydrates examined differed in both maximal yields and temporal patterns of yield of TCACP.

Animal Feed↗
PubMed2000

On the behavior of alpha,beta-unsaturated thioaldehydes and thioketones in the Diels-Alder reaction.

Alpha,beta-unsaturated thioaldehydes and thioketones, R1CH=CH-C(=S)R2, are prepared in situ by the reaction between the corresponding carbonyl compounds and bis(dimethylaluminum) sulfide. These compounds undergo [4 + 2] self-dimerization reactions in which one molecule serves as the heterodiene component and the other as the dienophile to afford different types of dimeric products depending on the R1 and R2: 1,2-dithiin and 1,3-dithiin (R1 = R2 = H), 1,2-dithiin (R1 = Ph, R2 = H, CH3), or dihydrothiopyran (R1 = R2 = Ph). These differences in selectivity are explained on the basis of the relative energies evaluated by molecular orbital (MO) calculations at the DFT (density functional theory) level. The calculations show that in the dimerization reaction of thioacrolein (I), the head-to-tail (S-C-S bonded) dimers are kinetically more stable by about 5 kcal/mol but slightly thermodynamically unstable by about 2 kcal/mol than the head-to-head (S-S bonded) dimers. The calculations on thiocinnamaldehyde (IV) indicate that the dimerization reactions of phenyl-substituted alpha,beta-unsaturated thioaldehydes and thioketones are almost equally controlled by thermodynamic and kinetic factors. These unsaturated thiocarbonyl compounds also function as heterodienes (C=C-C=S) in the cycloaddition reaction with norbornadiene and as dienophiles (C=S) in the reaction with cyclopentadiene.

Aldehydes↗
PubMed2000

Performance of dairy cattle fed citrus pulp or corn products as sources of neutral detergent-soluble carbohydrates.

The effects of modifying the dietary profile of neutral detergent-soluble carbohydrates (NDSC) on milk production and rumen fermentation were determined. Corn silage and alfalfa hay-based diets were formulated to contain 40% calculated NDSC supplied primarily by dried citrus pulp as a source of neutral detergent-soluble fiber (NDSF), or corn products as sources of starch. Diets were compared within cow with reversal experiments with two periods. In experiment 1, 11 multiparous Holstein cows including three ruminally cannulated animals were individually fed diets containing 23.6% citrus pulp (diet CPD) or 25.3% corn hominy (diet HD) on a dry matter basis. In experiment 2, 184 animals fed as two groups received diets containing 20.5% citrus pulp (diet CPD) or 19.5% cornmeal (diet CMD). Diets CPD provided more dietary NDSF and HD and CMD more starch. In experiment 1, cows fed HD had a greater milk protein percentage (+0.12%), and tended to yield more milk protein (0.08 kg/d) than cows fed CPD. Although ruminal H+ concentrations did not differ between diets, diet x time postfeeding interactions were significant. Ruminal organic acid concentrations did not differ between diets. In experiment 2, cows fed CMD yielded more milk (3.9 kg/d), 3.5% fat- and protein-corrected milk (2.6 kg/d), fat (0.05 kg/d), and protein (0.08 kg/d), whereas cows fed CPD produced greater concentrations of fat (+0.18%), and milk urea nitrogen (0.76 mg/dl). Modifying the proportions of NDSC in the diet can alter milk production and composition, the pattern of ruminal fermentation, and N utilization in dairy cows.

Animal Feed↗
PubMed1991

Evaluation of the sedative combination of nitrous oxide and orally administered diazepam.

The effects of nitrous oxide/oxygen and oral diazepam, administered individually and in combination, on memory and psychomotor coordination were evaluated. Forty healthy adult volunteers (53% male) were randomly assigned to one of four conditions: (1) 100% oxygen and placebo, (2) 50% nitrous oxide/50% oxygen and placebo, (3) 100% oxygen and 20 mg diazepam, or (4) 50% nitrous oxide/50% oxygen and 20 mg diazepam. There was no significant difference between groups with respect to age or weight. Participants' performance was tested in two areas: (1) a visual recall and recognition task and (2) psychomotor coordination as indicated by performance on Trieger's modification of the Bender Gestalt Test. There was no significant difference between the effects of nitrous oxide or diazepam on memory given individually or in combination. Significant differences in psychomotor coordination were seen when comparing groups 2, 3, and 4 with group 1. However, no significant differences existed between groups 2, 3, and 4, indicating that nitrous oxide and diazepam both affect coordination but that their effects are not additive when combined in this manner. The trends in both the memory and psychomotor data suggest diazepam to have a greater effect than nitrous oxide, and the combination to have a greater effect than either agent individually. Further investigation in this area is needed.

Adult↗
PubMed1991

Comparative anatomic study of anterior and posterior iliac crests as donor sites.

Ten fixed human cadaver iliums from elderly persons were studied to compare the amounts of graft material present in the anterior and posterior ilium. Average intracortical volume of surgically accessible marrow space was 15.75 mL for the anterior and 39.24 mL for the posterior ilium. Comparison of marrow volume underlying equal surface areas revealed values of 8.4 mL for the anterior and 14.8 mL for the posterior ilium. The average total volume of compressed cancellous bone obtained was 12.87 mL for the anterior and 30.31 mL for the posterior ilium. The ratio of cortical bone window surface area to resultant immediately accessible graft material was 1:0.49 for the anterior and 1:0.75 for the posterior ilium. These results confirm the greater availability of cancellous bone in the posterior ilium.

Aged↗
PubMed1991

Improvement in myofascial pain and headaches following TMJ surgery.

Fifty patients diagnosed with TMJ internal derangement, myalgia, and headaches, who had not responded well to nonsurgical management and subsequently underwent TMJ surgery, were retrospectively evaluated. The patients were mailed a survey asking them to evaluate the following symptoms: joint pain, joint noise, facial muscle pain, cervical and shoulder muscle pain, headache frequency and intensity, and overall head and neck pain. The majority of patients reported their symptoms as moderate to severe prior to treatment. In addition to reporting decreases in TMJ pain and noise after surgery, the majority of patients responding also reported decreases in myalgia and headaches. Twenty-two patients managed nonsurgically at the same center were also surveyed. The proportion of patients reporting their symptoms as moderate to severe prior to treatment was lower in this group. Patients reporting decreases in myalgia and headaches were in the minority. The study demonstrates that myalgia and headache symptoms associated with TMJ dysfunction that are poorly responsive to nonsurgical management may improve following TMJ surgery.

Adolescent↗
PubMed1989

Internal derangement of the TMJ: changes associated with mandibular repositioning and orthodontic therapy.

Because of its apparent success in relieving symptoms, especially pain, anterior mandibular repositioning therapy is a popular mode of nonsurgical treatment for patients with painful, clicking internal derangement of the temporomandibular joint. Posterior open bites are a frequent consequence of such therapy and may necessitate either continued appliance wear or closure by equilibration, prosthetics, or orthodontics. The anatomic and functional changes that occur subsequent to mandibular repositioning during orthodontic closure of the posterior open bite are not well understood. A case of a patient with a Class II, deep bite malocclusion and painful internal derangement of the TMJ is presented. Transcranial and cephalometric radiographs, arthrograms, and mandibular movement recordings were obtained before treatment and after both repositioning therapy and orthodontic treatment. Regarding occlusal improvement and pain relief, the treatment was successful. However, not all of the changes that occurred during repositioning therapy were maintained after orthodontic treatment. The strategy used in this case (mandibular repositioning/orthodontic finishing) was evaluated by an examination of these anatomic and functional changes with a discussion centered on the possible mechanisms involved.

Adolescent↗
PubMed1987

Residual alveolar ridge maintenance with a new endosseous implant material.

In an effort to maintain the height of the residual alveolar ridge, Bioglass cones were placed in fresh sockets after tooth extraction. Today the emphasis is on maintaining the residual alveolar ridge instead of letting it resorb and subsequently resorting to heroic efforts for augmentation. To date, 242 cone implants have been placed in 29 patients. Implant follow-up observation time ranged from 12 to 32 months with an average of 19.9 months. Twenty-seven patients have been fitted with dentures. To date seven implants (2.9%) have been lost. The Bioglass implants appear to be highly biocompatible as evidenced by absence of infection, normal mucosal healing, and radiographic evidence of bone healing around the implants. Evaluation of several implants reexposed surgically revealed new bone in direct contact with the immobile implants circumferentially. The problem of implant dehiscence that started to occur after approximately 10 months in other investigations had not manifested itself in the Bioglass implant patients who have been wearing their dentures for at least 12 months.

Alveolar Process↗
PubMed1986

Healing following meniscoplasty, eminectomy, and high condylectomy in the monkey temporomandibular joint.

The healing of meniscoplasty, eminectomy, and high condylectomy was studied in five Macaca fascicularis monkeys. After five months of healing, no discontinuity defects were found in any of the plicated menisci, and all recontoured bone surfaces had new soft tissue linings. Fibrous adhesions to the adjacent plicated meniscus developed in 62.5% of the recontoured bony surfaces.

Animals↗
PubMed1985

Gaucher's disease affecting the mandible.

A case of Gaucher's disease affecting the left body of the mandible is presented. Dentists can recognize this uncommon disease through the medical history of the patient, the presence of characteristic Gaucher cells on biopsy of the lesion, and decreased serum levels of the enzyme glucocerebrosidase.

Gaucher Disease↗
PubMed1985

Facial nerve injury during surgery of the temporomandibular joint: a comparison of two dissection techniques.

Changing the dissection technique for gaining access to the temporomandibular joint decreased the incidence of facial nerve injury from 25% to 1.7%. This decrease can be attributed to the elimination of both development of a skin flap and dissection of tissue overlying the lateral capsule. Normal anatomic variation in the distribution of facial nerve branches may relate to the incidence of clinically apparent injury.

Dermatologic Surgical Procedures↗
PubMed1984

Albright's syndrome with reactivation of fibrous dysplasia secondary to pituitary adenoma and further complicated by osteogenic sarcoma. Report of a case.

To our knowledge, this is the only reported case of Albright's syndrome with reactivation of the fibrous dysplasia in adulthood, a marked elevation of growth hormone secondary to a pituitary adenoma, and development of osteosarcoma within the reactivated fibrous dysplasia. In addition, this patient also had hyperthyroidism with normal TSH levels, indicating the presence of two separate endocrinopathies. Reactivation of the fibrous dysplasia after years of arrested growth in this patient is good evidence that fibrous dysplasia does not "burn out" after adolescence but that growth ceases only when growth hormone declines to adult levels.

Adenoma↗
PubMed1984

Histologic appearance of the bilaminar zone in internal derangement of the temporomandibular joint.

Light microscopy was used to examine twenty-six specimens of bilaminar zone tissue excised during surgery for correction of internal derangement of the temporamandibular joint. Each of the specimens was examined for the presence of inflammation, amount of vascularity, arterial wall thickness, presence of fat, appearance of collagen, and amount of elastin present. Wide variation in the histologic appearance was noted among the specimens, although no significant inflammation was observed in any of them. Some indications that this tissue is undergoing adaptive changes include the presence of thickened arterial walls suggesting a decreased blood flow and the tendency for decreased amounts of elastin to be associated with denser-appearing collagen. There is also a tendency for patients with complete dislocation to exhibit less elastin than those with partial dislocation of the meniscus.

Adolescent↗
PubMed1984

Meniscoplasty of the displaced temporomandibular joint meniscus without violating the inferior joint space.

Twenty temporomandibular joints with anterior meniscus displacement, both with and without reduction, were treated by meniscoplasty of the superior lamina of the bilaminar zone through the superior joint space. Reduction of the eminence was also performed on each joint. All joints were judged markedly improved both by the surgeon and patients. With an average postoperative follow-up of 18.1 months, 13 (65%) of the joints were pain free and seven (35%) had mild, transient pain with prolonged hard chewing or prolonged wide mouth opening.

Adolescent↗