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Biomedical subjects

B L Schmidt

Publications and source records attributed to B L Schmidt.

At least 19 recordsLinked to original sources

Lingual nerve damage due to inferior alveolar nerve blocks: a possible explanation.

BACKGROUND: An explanation for the predominance of injuries to lingual nerves over those to inferior alveolar nerves as a result of inferior alveolar nerve blocks may be due to the nerves' fascicular pattern. A unifascicular nerve may be injured more easily than a multifascicular nerve. METHODS: The authors unilaterally dissected lingual and inferior alveolar nerves from 12 cadavers. They cut the specimens 2 millimeters above the lingula for both the lingual nerve and inferior alveolar nerve and opposite the site of the middle of the third molar for the lingual nerve, and they counted the number of fascicles at each site. RESULTS: For the lingual nerve at the lingula, the mean number of fascicles was three (range, one to eight). Four of the 12 nerves (33 percent) were unifascicular at this point. Opposite the third molar, the lingual nerve had a mean of 20 fascicles (range, six to 39). In every case, there were more fascicles in the third molar region than above the lingula in the same nerve. At the lingula, the inferior alveolar nerve had a mean of 7.2 fascicles (range, three to 14). CONCLUSION: This study may explain the observation that when an inferior alveolar nerve block causes permanent nerve impairment, the lingual nerve is affected about 70 percent of the time and the inferior alveolar nerve is affected only 30 percent of the time. In 33 percent of cases, the lingual nerve had only one fascicle at the lingula; a unifascicular nerve may be injured more easily than a multifascicular one. CLINICAL IMPLICATIONS: There is no known way to avoid the remote possibility of nerve damage resulting from an inferior alveolar nerve block. The lingual nerve may be predominantly affected because of its fascicular pattern.

Anesthesia, Dental↗

Importance of sample preparation for molecular diagnosis of lyme borreliosis from urine.

Urine PCR has been used for the diagnosis of Borrelia burgdorferi infection in recent years but has been abandoned because of its low sensitivity and the irreproducibility of the results. Our study aimed to analyze technical details related to sample preparation and detection methods. Crucial for a successful urine PCR were (i) avoidance of the first morning urine sample; (ii) centrifugation at 36,000 x g; and (iii) the extraction method, with only DNAzol of the seven different extraction methods used yielding positive results with patient urine specimens. Furthermore, storage of frozen urine samples at -80 degrees C reduced the sensitivity of a positive urine PCR result obtained with samples from 72 untreated erythema migrans (EM) patients from 85% in the first 3 months to <30% after more than 3 months. Bands were detected at 276 bp on ethidium bromide-stained agarose gels after amplification by a nested PCR. The specificity of bands for 32 of 33 samples was proven by hybridization with a GEN-ETI-K-DEIA kit and for a 10 further positive amplicons by sequencing. By using all of these steps to optimize the urine PCR technique, B. burgdorferi infection could be diagnosed by using urine samples from EM patients with a sensitivity (85%) substantially better than that of serological methods (50%). This improved method could be of future importance as an additional laboratory technique for the diagnosis of unclear, unrecognized borrelia infections and diseases possibly related to Lyme borreliosis.

Adolescent↗

Nicotine withdrawal hyperalgesia and opioid-mediated analgesia depend on nicotine receptors in nucleus accumbens.

The nucleus accumbens, as part of the mesolimbic dopaminergic reward pathway, mediates both addiction to and withdrawal from substances of abuse. In addition, activity of substances of abuse such as opioids in the nucleus accumbens has been implicated in pain modulation. Because nucleus accumbens nicotinic receptors are important in nicotine addiction and because nicotinic activity can interact with opioid action, we investigated the contribution of nucleus accumbens nicotinic receptors to opioid-mediated analgesia/antinociception. The response of the nociceptive jaw-opening reflex to opioids was studied in the rat, both before and during chronic nicotine exposure. In nicotine-naive rats, intra-accumbens injection of the nicotinic receptor antagonist mecamylamine blocked antinociception produced by either systemic morphine, intra-accumbens co-administration of a mu- and a delta-opioid receptor agonist, or noxious stimulation (i.e., subdermal capsaicin in the hindpaw); intra-accumbens mecamylamine alone had no effect. The antinociceptive effect of either morphine or noxious stimulation was unchanged during nicotine tolerance; however, intra-accumbens mecamylamine lost its ability to block antinociception produced by either treatment. Intra-accumbens mecamylamine by itself precipitated significant hyperalgesia in nicotine-tolerant rats which could be suppressed by noxious stimulation as well as by morphine. These results indicate that nucleus accumbens nicotinic receptors play an important role in both opioid- and noxious stimulus-induced antinociception in nicotine-naive rats. This role was attenuated in the nicotine-dependent state. The suppression of withdrawal hyperalgesia by noxious stimulation suggests that pain can ameliorate the symptoms of withdrawal, thus suggesting a possible mechanism for pain-seeking behavior.

Analgesia↗

The course of the temporal branch of the facial nerve in the periorbital region.

PURPOSE: This study identified the terminal temporal and zygomatic branches of the facial nerve as they enter the orbicularis oculi muscle and related these branches to identifiable surface markings. MATERIALS AND METHODS: The temporal and zygomatic branches of the facial nerve were dissected from 5 preserved cadavers (10 sides). The most superior temporal branch entering the orbicularis oculi muscle was identified and related to the lateral canthus of the eye. A vertical line was passed through this point so that the line was equidistant from the nasal tip and chin point. A line perpendicular to the vertical line through the lateral canthus served as the horizontal scale. Vertical and horizontal lines through the lateral canthus were used to establish the anatomic relationship between the lateral canthus and the branch of the temporal nerve entering the orbicularis oculi muscle. RESULTS: The temporal branch was an average of 2.85 +/- 0.69 cm superior to the lateral canthus and an average of 2.54 +/- 0.43 cm lateral to the lateral canthus as it courses into the orbicularis oculi muscle. At the lateral border of the orbicularis oculi muscle, where the temporal and zygomatic nerves insert into the muscle, the mean vertical distance between the temporal and zygomatic nerves was 1.72 +/- 0.62 cm. CONCLUSION: Incisions superior or inferior and parallel to the course of the facial nerve, can provide access to the fronto zygomatic suture and the superior and lateral orbit without damaging its branches.

Eyelids↗

The use of enucleation and liquid nitrogen cryotherapy in the management of odontogenic keratocysts.

PURPOSE: This study evaluated the use of enucleation and cryosurgery in the management of odontogenic keratocysts. PATIENTS AND METHODS: This study involved a retrospective review of 26 patients. All of the patients received a combination of enucleation and cryosurgery. Postoperative follow-up consisted of clinical and radiographic examinations. RESULTS: Before enucleation and cryotherapy, 22 of the 26 patients had received previous treatment consisting of enucleation alone. The average time from initial treatment to recurrence was 6.2 years. Twenty-three cases occurred in the mandible, 22 in the posterior (proximal to the canine), and 1 in the anterior mandible. Three cases involved the maxilla. Three of the 26 patients (11.5%) developed a recurrence after treatment. The average time from treatment to recurrence in these 3 patients was 1.6 years (range, 1.2 to 1.9 years). The remaining 23 patients (88.5%) had no evidence of clinical or radiographic recurrence. The average time of follow-up was 3.5 years (range, 2.0 to 10.0 years). CONCLUSIONS: Based on these results, the combination of enucleation and liquid nitrogen cryotherapy may offer patients improved therapy in the management of odontogenic keratocysts.

Adolescent↗

A financial analysis of maxillomandibular fixation versus rigid internal fixation for treatment of mandibular fractures.

PURPOSE: The aim of this study was to compare the cost-effectiveness of mandibular fracture treatment by closed reduction with maxillomandibular fixation (CRF) with open reduction and rigid internal fixation (ORIF). PATIENTS AND METHODS: This was a retrospective study of 85 patients admitted to the Oral and Maxillofacial Surgery Service at San Francisco General Hospital and treated for mandibular fractures from January 1 to December 31, 1993. The patients were divided into 2 groups: 1) those treated with CRF and 2) those treated with ORIF. The outcome variables were length of hospital stay, duration of anesthesia, and time in operating room. The charge for primary fracture treatment included the fees for the operation and hospitalization without any complications. Within the group of 85 patients treated for mandibular fractures in 1993, 10 patients treated with CRF and 10 patients treated with ORIF were randomly selected, and hospital billing statements were used to estimate the average charge of primary treatment. The average charge to manage a major postoperative infection also was estimated based on the billing statements of 10 randomly selected patients treated in 1992 (5 treated with CRF, 5 with ORIF) who required hospital admission for the management of a complication. The average total charge was computed by using the average charge for primary treatment plus the incidence of postoperative infection multiplied by the average charge for management of that complication. RESULTS: Eighty-five patients were included in the study. The average charge for primary treatment was $10,100 for the CRF group and $28,362 for the ORIF group. The average charge for the inpatient management of a major postoperative infection was $26,671 for the CRF group and $39,213 for the ORIF group. The average total charge for management of a mandible fracture with CRF was $10,927; the total charge for the ORIF group was $34,636. CONCLUSION: The results of this retrospective study suggest that the use of CRF in the management of mandibular fractures at our institution provides considerable savings over treatment by using ORIF. The use of ORIF should be reserved for patients and fracture types with specific indications.

Adult↗

Comparative evaluation of nine different enzyme-linked immunosorbent assays for determination of antibodies against Treponema pallidum in patients with primary syphilis.

Nine different enzyme-linked immunosorbent assays (ELISAs) with a sonicate or recombinant proteins of Treponema pallidum as antigen have been evaluated comparatively by testing 52 highly selected sera from patients with primary syphilis, all negative in the microhemagglutination test for T. pallidum (MHA-TP). Eight tests exhibited greater sensitivity (48.5 to 76.9%) than the commonly used Venereal Disease Research Laboratory test (44.2%). Higher sensitivity could be related to (i) the volume and dilution of the serum, (ii) the design of the assay (capture and competitive tests showed higher sensitivity than sandwich-based assays), and (iii) the ability to detected specific immunoglobulin M antibodies. The specificity of the ICE Syphilis and the Enzygnost Syphilis tests was 99.5 and 99.8%, respectively, as determined by routine testing of 2, 053 unselected sera in comparison with the MHA-TP test. ELISAs tested offered high sensitivity in patients with primary syphilis; however, recommendations to use these tests as screening assays do need further data on specificity and reactivity in late stages of the disease.

Antibodies, Bacterial↗

Significance of laboratory findings for the diagnosis of neurosyphilis.

Our objective is to assess the specificity and sensitivity, and thus elaborate the relevance, of different laboratory findings for the diagnosis of neurosyphilis. One hundred and fourteen HIV-negative pairs of serum and cerebrospinal fluid (CSF) samples were examined by the Venereal Disease Research Laboratory (VDRL) test, a fluorescent treponemal antibody-absorption (FTA-ABS) test, microhaemagglutination assay with Treponema pallidum antigen (MHA-TP) test (serum) and Treponema pallidum haemagglutination assay (TPHA) test (CSF); further, albumin, total protein, and total IgG were determined and, in the CSF, cell count was performed. The donors were 60 patients with active neurosyphilis and 54 healthy persons with a former history of syphilis and with persisting positive results in the T. pallidum haemagglutination tests (serum: MHA-TP, CSF: TPHA), who supplied specimens for control. Albumin quotient, IgG index, TPHA index, modified TPHA index, Intrathecally produced T. pallidum Antigen (ITpA) index, its 2 modifications and, in 12 samples, the adenovirus group antibody (AVGA)/TPHA index were ascertained. The specificity and sensitivity of the TPHA index were 100% and 98.3%, of the modified TPHA index 50.0% and 96.7%, of the ITpA index 42.6% and 90.0%, of the modified ITpA indices 51.8% and 68.3% (first modification) and 53.7% and 63.3% (second modification). The AVGA/TPHA index yielded a specificity of 91.7% (11/12). The CSF VDRL test was positive in 55/60 (91.7%) of samples from patients with neurosyphilis and in none of the controls (0/54). A CSF-TPHA titre greater than 1:320 was observed in 59/60 (98.3%) of the neurosyphilis specimens and in none of the controls (0/54). A TPHA index above an outcome of 70, a positive CSF-TPHA test at a titre greater than 1:320 and, with lower sensitivity, the criteria of the Centers for Disease Control (CDC) guidelines yield the most reliable results for laboratory support to a diagnosis of neurosyphilis. The modified TPHA index, the ITpA index, and its 2 modifications produce results of minor sensitivity and poor specificity. Observations on the AVGA/THPA index are too limited yet for judgement. The diagnostic significance of a CSF-TPHA titre above 320 needs further confirmation on a greater number of observations made by different laboratories.

Adult↗

The removal of plates and screws after Le Fort I osteotomy.

PURPOSE: This study is a retrospective chart review designed to evaluate the incidence and reasons for removal of plates and screws after Le Fort I osteotomy. PATIENTS AND METHODS: The study sample consisted of patients who underwent Le Fort I osteotomy at the University of California, San Francisco, and Northwestern University in Chicago between December 1985 and December 1994. All patients in the study were treated with internal fixation using 2.0-mm plates and screws. All data were obtained from medical records and operative reports. The following intraoperative variables were evaluated: hardware material, plate size and shape, plate location, screw size, graft material, and intraoperative complications. For patients requiring removal of hardware, the number, location and type of plates and screws removed were recorded, as well as the reasons for removal. RESULTS: A total of 738 plates were placed in 190 patients. Twenty-one of the 190 patients (11.1%) had at least a portion of the hardware removed because they either requested removal or required removal secondary to complications related to the plate or screw. This represented 70 of 738 plates (9.5%). The percentage of titanium plates removed was greater than the percentage of Vitallium plates removed. The reasons for removal included pain, palpation by the patient, sinusitis, temperature sensitivity, infection, and patient request. CONCLUSION: Only a small number of patients (10.6%) develop complications from plates or screws that required their removal. In each case, prompt removal constituted adequate management.

Adult↗

The distribution of the auriculotemporal nerve around the temporomandibular joint.

OBJECTIVE: The purpose of this cadaver dissection was to study the position of the auriculotemporal nerve in relation to the mandibular condyle, capsular tissues, articular fossa, and lateral pterygoid muscle and to evaluate the anatomic possibility of nerve impingement or irritation by the surrounding structures. STUDY DESIGN: Eight cadaveric heads (16 sides) were dissected. The auriculotemporal nerve was identified by following its course around the middle meningeal artery. The course of the nerve trunk was dissected from the middle meningeal artery to the terminal branches within the temporomandibular disk. The horizontal distance between the auriculotemporal nerve and the medial portion of the condyle/condylar neck was measured. The vertical distance from the most superior portion of the articular condyle to the superior border of the auriculotemporal nerve was measured. RESULTS: The auriculotemporal nerve was identified on each side, and a single trunk was evident along the medial aspect of the condylar neck. At the posterior border of the lateral pterygoid muscle, the nerve trunk was in direct contact with the condylar neck in every specimen. The average vertical distance between the superior condyle and the nerve was 7.06 mm (+/- 3.21 mm); the range was 0 to 13 mm. The vertical distance between the nerve and the superior condyle on one side of the specimen did not correlate with the distance on the contralateral side. CONCLUSION: The auriculotemporal nerve trunk has a close anatomic relationship with the condyle and the temporomandibular joint capsular region, and there is evidence of a possible mechanism for sensory disturbances in the temporomandibular joint region. In all cases, the nerve was in direct contact with the medial aspect of the capsule or condylar neck. Because there is no correlation between the positions of the nerves on the right and left sides, only one side may be affected. The nerve was also observed to course in direct apposition to the lateral pterygoid muscle. The findings support the hypothesis that the anatomic and clinical relationship of the auriculotemporal nerve to the condyle, articular fossa, and lateral pterygoid muscle may be causally related to compression or irritation of the nerve, producing numbness or pain, or both, in the temporomandibular joint region.

Adult↗

Intraorbital squamous epithelial cyst: an unusual complication of Silastic implantation.

Thin Silastic sheet alloplasts (Dow Corning, Midland, MI, U.S.A) are commonly used to reconstruct posttraumatic orbital floor defects. Complications associated with orbital Silastic implantation include infection, migration, and extrusion. The authors report an unusual case of an intraorbital, squamous, epithelial-lined cyst appearing as progressive vertical globe dystopia and proptosis occurring after Silastic reconstruction of a traumatic orbital floor defect.

Bone Cysts↗

Comparison of full thickness skin graft "take" after excision with the carbon dioxide laser and scalpel.

SPECIFIC AIM. To evaluate the take of skin grafts on conventionally prepared beds and on beds prepared by a carbon dioxide laser, with and without abrasion of the bed. SIGNIFICANCE. Graft take is dependent on hemostasis, immobility, and nutrition of the graft. Scalpel excision of the skin graft can be associated with hemostatic difficulties and laser treatment of the skin graft bed can provide hemostasis. Abrasion of the bed after laser treatment may then be a means of opening small lymphatic and blood vessels to maintain the graft. Laser treatment followed by abrasion of the bed may provide an ideal graft base before suturing of the skin graft. MATERIAL AND METHODS. Full-thickness skin grafts were taken with a scalpel at three sites on the dorsal skin of 24 guinea pigs. The three beds were prepared with pressure alone to provide hemostasis, laser vaporization followed by abrasion with gauze to produce pinpoint bleeding, and laser vaporization alone. The original skin from each of the sites was then sutured back in place. At postoperative days 1, 3, 5, 10, 21, and 35 the graft sites were assessed clinically for "take." Laser Doppler measurements were also made to evaluate blood flow. Histologic sections of the three sites were prepared. Immunohistochemical analysis was performed to evaluate cell proliferation and angiogenesis. RESULTS. For the animals sacrificed through day 10 the rate of take for the sites that were not lased was 100%. For the sites that were lased alone and lased and abraded the rate of take was 71% with no difference between the two techniques. The lased sites demonstrated increased inflammatory response and graft necrosis. Immunohistochemical analysis showed increased cellular proliferation and angiogenesis in the bed. DISCUSSION. Grafts take best on a scalpel-prepared bed. Laser preparation of the bed, with or without abrasion, demonstrates decreased "take." Therefore the carbon dioxide laser is not a recommended means to take a graft or prepare the graft bed.

Animals↗

PCR in laboratory diagnosis of human Borrelia burgdorferi infections.

The laboratory diagnosis of Lyme borreliosis, the most prevalent vector-borne disease in the United States and endemic in parts of Europe and Asia, is currently based on serology with known limitations. Direct demonstration of Borrelia burgdorferi by culture may require weeks, while enzyme-linked immunosorbent assays for antigen detection often lack sensitivity. The development of the PCR has offered a new dimension in the diagnosis. Capable of amplifying minute amounts of DNA into billions of copies in just a few hours, PCR facilitates the sensitive and specific detection of DNA or RNA of pathogenic organisms. This review is restricted to applications of PCR methods in the diagnosis of human B. burgdorferi infections. In the first section, methodological aspects, e.g., sample preparation, target selection, primers and PCR methods, and detection and control of inhibition and contamination, are highlighted. In the second part, emphasis is placed on diagnostic aspects, where PCR results in patients with dermatological, neurological, joint, and ocular manifestations of the disease are discussed. Here, special attention is given to monitoring treatment efficacy by PCR tests. Last, specific guidelines on how to interpret PCR results, together with the advantages and limitations of these new techniques, are presented.

Borrelia burgdorferi Group↗

Diagnosis and management of root fractures and periodontal ligament injury.

Although root fractures are among the less common oral injuries (6 percent), a careful diagnostic evaluation of such injuries is required to arrive at an appropriate treatment plan. The position of the fracture in the root will determine the proper management. The problem of luxation due to trauma often involves the use of dental splints, which, if not properly designed, may cause root resorption, loss of alveolar bone, pulpal necrosis and pulp canal obliteration. The guidelines for the type of splint to use and conditions under which it should be placed are presented.

Dental Pulp↗

The presence of the antilingula and its relationship to the true lingula.

20 cadaver mandibles were studied for the presence of an antilingula and its relationship to the true lingula and mandibular foramen. Three independent observers evaluated the mandibles for the presence of an antilingula. It could be identified on all 40 sides. On 9 of the sides, there was complete concordance on the position of the antilingula between the three observers. On the other 31 sides, however, there was a variation between observers of up to 11 mm. In only 43% of the cases was the antilingula within 5 mm of the true lingula. In most cases, the true lingula was postero-inferior to the antilingula. There was a negative horizontal and positive vertical correlation between the position of the antilingula on one side and its position on the contralateral side.

Aged↗

Detection of Borrelia burgdorferi DNA by polymerase chain reaction in the urine and breast milk of patients with Lyme borreliosis.

Current laboratory diagnosis of Lyme borreliosis relies on tests for the detection of antibodies to Borrelia burgdorferi with known limitations. By using a simple extraction procedure for urine samples, B. burgdorferi DNA was amplified by a nested PCR with primers that target the specific part of the flagellin gene. To control possible inhibition of the enzyme (polymerase), a special assay using the same primers was developed. We examined 403 urine samples from 185 patients with skin manifestations of Lyme borreliosis. Before treatment, B. burgdorferi DNA was detected in 88 of 97 patients with Lyme borreliosis. After treatment, all but seven patients became nonreactive. Six of these seven persons suffered from intermittent migratory arthralgias or myalgias, and one from acrodermatitis chronica atrophicans. Two of 49 control patients with various dermatologic disorders and none out of 22 presumably healthy persons were reactive in the PCR. In addition to urine, breast milk from two lactating women with erythema migrans was tested and also found reactive. Borrelia burgdorferi DNA can be detected with high sensitivity (91%) by a nested PCR in urine of patients with Lyme borreliosis. In addition, this test can be a reliable marker for the efficacy of treatment.

Animals↗