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Countercurrent transfer of 125I-LHRH in the perihypophyseal cavernous sinus-carotid rete vascular complex, demonstrated on isolated pig heads perfused with autologous blood.

The objective of the study was to determine whether the local permeability of luteinizing hormone-releasing hormone (LHRH) from the venous blood of the perihypophyseal cavernous sinus into the arterial blood of the carotid rete, supplying the brain and hypophysis in gilts, depends on the day of the estrous cycle, as well as to determine whether this transfer exists when LH concentration in the blood is reduced (the experimental short-loop negative feedback for LH secretion after estradiol injection in ovariectomized gilts). Experiments were conducted on isolated gilt heads with necks, on chosen days of the estrous cycle (n = 40), and on previously ovariectomized gilts treated with estradiol benzoate (EB) (n = 5) or corn oil (n = 3). After exsanguination, the gilt heads with necks were disarticulated and about 30-45 min later were supplied with autologous, oxygenated, and heated blood at a stable blood flow and pressure through the left carotid artery for 30 min. 125I-LHRH was infused into both cavernous sinuses through the cannulated angularis oculi veins for 5 min. After 125I-LHRH infusion, radiolabeled LHRH was found (P < 0.001) in arterial blood taken from the carotid rete through the open right carotid artery in all animals used in the experiment: on Days 1-2 (six gilts), on Days 12-14 (seven gilts) of the estrous cycle, and in five ovariectomized gilts during negative feedback for LH surge (40 hr after EB). No significant radioactivity of 125I-LHRH was found in the arterial blood on Days 3-5 (n = 6), 9-11 (n = 4), and 15-21 (n = 17) of the estrous cycle. A very low level of radioactivity was found in the ovariectomized control group after the injection of corn oil (n = 3). These results provide evidence for the permeability of LHRH from the venous to the arterial blood and its retrograde transport with the arterial blood to the hypophysis and brain, after the ovulation period (Days 1-2) and on Days 12-14 of the estrous cycle. This suggests that a close relationship exists between the day of the estrous cycle and LHRH permeability from the venous to the arterial blood in the perihypophyseal cavernous sinus-the carotid rete complex in gilts-and that this mechanism may be included in a short-loop feedback for LHRH secretion.

Animals↗

Reaction of the pterygomaxillary fissure and the condylar cartilage to intermaxillary Class III magnetic mechanics.

The skeletal reaction to Class III intermaxillary magnetic mechanics was previously found to affect two target areas, the pterygomaxillary fissure (PMF) and the condylar cartilage. The objectives of this study were to analyze, radiographically and histologically, the response of these tissues to Class III intermaxillary functional orthopedic magnetic appliance (FOMA III), and to postulate possible models of their dichotomous biomechanism. Nine Macaca fascicularis monkeys received periodic administration of vital bone procion dye and were treated for 4 months with FOMA III (6 subjects) and sham appliance (3 subjects). The PMF (the target area of the midfacial complex) demonstrated a decreased skeletal reaction in inferosuperior and lateromedial directions. Cephalometrically, the lowermost PMF point was displaced inferiorly 1.98 +/- 1.74 mm and 0.42 +/- 0.38 mm and anteriorly 1.42 +/- 0.96 mm and 0.58 +/- 0.38 mm in the treated and control groups, respectively. The displacement of the uppermost PMF point, compared with the lowermost point, was three to five times lower. Histologically, two modes of response were found; first, a sutural response (disarticulation and osteogenesis) of the palatomaxillary and pterygopalatine sutures, which was distinctive of the lateral PMF aspect, and second, a dentosutural response, which was characteristic of the medial PMF aspect (bony microfractures between the third molar germ and the maxillary tuberosity in conjunction with mild sutural response). In the mandible, a discrepancy was found between the histologic and the cephalometric findings. Radiographically, mandibular length was unaffected after 4 months of treatment, and the distance condylion-pogonion was equally increased in the treated (0.75 +/- 0.78 mm) and the control animals (0.77 +/- 0.32 mm). Histologically, however, the condylar cartilage demonstrated increased osteoclastic activity at the zone of endochondral ossification and a decreased apposition rate at the adjacent bony trabeculae. Conceivably, the two target areas (PMF sutures versus condylar cartilage) demonstrate two diverse time-related responses that are either unrelated or interrelated to each other. An unrelated tissue response suggests that tissue stimulation (sutural) is always superior to tissue suppression (condylar). Another possible unrelated tissue reaction implies diverse response velocity (high sutural, low condylar). An interrelated mechanism suggests that an applied force will dissipate initially at the less resistant target area (sutures), and will subsequently affect the more resistant target area (condyle) once the sutural resistance exceeds a certain threshold. The fact that no pathologic change was found in the condylar cartilage encourages a long-term use of the FOMA III appliance, initiating treatment at an early skeletal age.

Animals↗

Basilar clefting: a familial condition?

Excavation at the deserted medieval village of Quattro Macine, Apulia revealed two ruined churches and associated cemeteries of stone-lined tombs. Typically, a tomb contained an articulated burial and bundles of disarticulated bone, no doubt, representing family tombs that were re-opened several times during the medieval period. In one tomb, two examples of basilar clefting, a manifestation of occipital vertebra, were recorded. Apparently, this rare condition has not been recorded in archaeological material. Its presence in two individuals from the same grave is the first evidence that there is a genetic component in this rare anatomical variant.

Archaeology↗

The neglected maxillary process of the palatine bone.

In most recent anatomy textbooks as well as in the latest anatomical nomenclature, the maxillary process of the palatine bone is not mentioned at all. The maxillary process is, however with rare exceptions, always present as an important part of the closure of the hiatus sinus maxillaris. In our material consisting of 200 disarticulated, macerated skull bones and 25 specimens of maxillary sinus, the maxillary process was missing in only 5 cases (2.2%). This process develops in the second year of life and displays different shapes. It can be long and slender or wide and round shaped. Its upper margin is more or less concave, corresponding to the margin of the hiatus over which it is bent. Its inferior margin can be smooth or irregular. In instances in which maxillary sinus is double, the os palatinum has two maxillary processes, so that both sinuses are partly closed with the maxillary process of the palatine bone.

Adolescent↗

Halving the number of leg amputations: the influence of infrapopliteal bypass.

A retrospective review of amputations in patients with vascular disease during 10 years in Bispebjerg Hospital was undertaken. There were 1383 amputations leading to 1167 final level amputations. In previously independent patients there were 482 below knee amputations (BKA), 476 above knee amputations (AKA) and 43 had disarticulations in the ankle, knee or hip. During the period studied the number of final level amputations in independent patients were halved from 122 in 1981 to 58 in 1990. A similar reduction was also found in the total number of amputations: from 171 to 90, and in the number of reamputations: from 35 to 21. However, amputations in patients from long stay institutions remained at a constant level by on average 17 per year. The decrease in amputation rate took place synchronously with an increasing use of bypass to crural and pedal arteries as well as an overall increase in vascular reconstructions and angioplasties of more than 100%. However, the BKA/AKA ratio decreased from 1.12 to 0.67 (p < 0.005).

Adult↗

Primary mandibular reconstruction with bridging plates.

25 cases in which the mandible was resected and reconstructed using a reconstruction plate (AO titanium reconstruction system and Leibinger titanium reconstruction system) are presented. 16 patients suffered from oral carcinoma, 7 presented with odontogenic tumours and 2 had chronic osteomyelitis of the mandible. The mean age was 54.2 years, the male to female ratio was 2.6:1. 3 patients had a reconstruction plate for mandibular resection without continuity defect (marginal resection), in all the other patients the reconstruction plate bridged a mandibular resection with a continuity defect: 13 were located in the body, body-angle or ascending ramus with preservation of the mandibular condyle; 4 hemimandibulectomies with disarticulation of the TMJ; and 5 involved the anterior arch, crossing the midline. 12 patients received radiotherapy (3 pre-operatively). Only 3 patients with significant local side effects needed the treatment to be stopped for a period of time. There was no perioperative mortality. Only one plate was removed. Although minor complications were noted in 11 patients, the general improvement in the functional and cosmetic balance of the patients when compared with patients in whom no plate was used, justifies the use of this reconstruction system, in our opinion.

Adolescent↗

Massive fibrolipoma of a toe.

Soft-tissue tumors of the toes are not particularly common; more tumors of the toes arise from the skin. The deeper tumors can be either benign or malignant and must be treated with caution until a histologic diagnosis has been made. However, malignant soft-tissue tumors of the toes are fairly rare. An unusual case of a massive benign lipoma was treated by an excisional biopsy (disarticulation).

Foot Diseases↗

Local anesthetic infusion through nerve sheath catheters for analgesia following upper extremity amputation. Clinical report.

BACKGROUND AND OBJECTIVES: Reports about the efficacy of local anesthetic perfusion of nerve stumps following lower extremity amputation are conflicting. We report our experience with this technique following amputation of the upper extremity. METHODS: Six consecutive patients undergoing proximal upper extremity amputations (four forequarter amputations and two shoulder disarticulations) for malignancy were prospectively observed. In all patients, catheters were placed within the amputated nerve sheaths at the conclusion of the procedure. Bupivacaine. 0.25%, was administered through each catheter as a bolus and then as a continuous infusion for at least 72 hours after surgery. Narcotic usage, level of pain as reported verbally, and presence of phantom limb pain during the infusion were recorded. For at least 1 year after operation, data were gathered on the presence of phantom limb pain and its intensity during each follow-up visit. RESULTS: Complete analgesia was achieved in all patients by postoperative day 2. Narcotic usage was low. Three of the six patients reported phantom limb pain during follow-up evaluation. CONCLUSIONS: Continuous local anesthetic perfusion of amputated nerves via a catheter placed under direct vision provided excellent postoperative analgesia. The incidence of phantom limb pain for cancer patients did not differ from that previously reported but was easily managed pharmacologically. The technique may also be efficacious for traumatic amputations.

Adult↗

[Evaluation of tympanometric alterations in patients subject to general anesthesia with nitrous oxide].

UNLABELLED: The nitrous oxide is an inhaling gas that can increase intratympanic pressure during the anesthetic act and cause negative pressure after it is discontinued, mainly in patients with Eustachian tube dysfunction. These pressure variations may come up with clinical implications such as tympanic membrane rupture, ossicular system disarticulation, haemotympanum, barotraumas, prosthesis displacement stapaedotomy and tympanic graft lateralization after tympanoplasty, in addition to serous fluid entrance into the middle ear during the negative pressure phase. AIM: To evaluate the nitrous oxide influence on the middle ear pressure in a population without tube malfunction performing pre and postoperative tympanometry. STUDY DESIGN: Transversal cohort. MATERIAL AND METHOD: A prospective study was carried out with Universitário Clementino Fraga Filho Hospital- UFRJ intern patients, subject to general anesthesia with the use of 50% nitrous oxide from April to June 2003. It was also evaluated whether the duration of surgery, associated anesthetics, presence of allergic rhinitis and nasal septal deviation could contribute to the appearing of intratympanic pressure alteration. RESULTS: The sample is made up of 50 patients, in almost half of them (48%), postoperative tympanometry alterations (type C curve) were found, when comparing to the preoperative tympanometric control (type A curve). Neither sex nor age interfered in the appearing of tympanometry alterations during the post operative as well as the surgery timing. The anesthetic type volatile associate, nasal septal deviation and allergic rhinitis were not able to influence during the postoperative middle ear pressure. CONCLUSION: The nitrous oxide modifies intratympanic pressure during the anesthetic act as well as after it was discontinued.

Acoustic Impedance Tests↗

An in vitro biomechanical evaluation of bone cements used in percutaneous vertebroplasty.

The purpose of this study was to determine the strength and stiffness of osteoporotic vertebral bodies (VBs) subjected to compression fractures and subsequently treated with bipedicular injections of various polymethylmethacrylate cements. Ten spines were harvested from nonembalmed female cadavers (age 68.6 +/- 13.7 years) and evaluated for bone mineral density using the dual energy X-ray absorptiometry method (t-score = -2.3 +/- 2.4). The 50 VBs (L1-L5) were disarticulated, compressed in a materials testing machine to determine initial strength and stiffness, and then assigned to one of six groups. Two of these groups (n = 8, n = 9) concerned experimental cements, the results of which are not reported here. The 33 vertebral bodies in the remaining four groups were left untreated or were repaired using a transpedicular injection of one of three commercially available polymethylmethacrylate cements. These four groups were: a) no treatment (no cement, n = 8); b) Simplex P (n = 9); c) Cranioplastic (n = 8); and d) Osteobond (n = 8). The VBs were then compressed again according to the initial protocol, and posttreatment strength and stiffness were measured. Results suggested that bipedicular injection of Simplex P and Osteobond restored VB stiffness to initial values, whereas VBs injected with Cranioplastic were significantly less stiff than in their initial state. VBs injected with cement (regardless of type) were significantly stronger than they were initially.

Absorptiometry, Photon↗

Evolution of speech and voice following supracricoid partial laryngectomy.

The evolution of voice and speech parameters following supracricoid partial laryngectomy (SCPL) has been evaluated in a prospective fashion over an 18-month period of time in three patients using the Computerized Speech Lab (from Kay Elemetrics). Preliminary results demonstrate the post-operative instability of voice parameters. Speech parameters remain stable with time. Our data stresses that voice is attained post-operatively even if one arytenoid cartilage is disarticulated at time of resection.

Aged↗

The work of indebtedness: the traumatic present of late capitalist Chile.

In political and biomedical discourses, "posttraumatic stress disorder" has become a set of organizing concepts for trauma and traumatic memory. These concepts, however, are predicated on an understanding of traumatic memory as a discrete etiological event that, when reexperienced, is productive of symptoms. In this essay, I explore alternative framings of trauma that arise out of historical changes in political economic language and from experiences of monetary, historical, and affective indebtedness in Santiago, Chile. This ethnographic research is based in an historically leftist población (poor urban sector) and follows the interwoven narratives of a formerly exiled communist militant and her adopted daughter. Throughout this essay, I describe the mother's attempts to inhabit an untimely language of socialist politics and the daughter's rejection of both this language and her mother's pain. I elaborate on how these attempts are products of and productive of monetary and intersubjective indebtedness in a neoliberal present. By describing the differing historical languages inhabited by these subjects, I attempt to evoke an understanding of trauma not as an individual possession or etiological event, but rather as a referential dissonance in the neoliberal context. This referential dissonance emerges from the gap between the historical languages that inform subjectivities. I explore how such a gap can create contexts in which the everyday itself both threatens the disarticulation of the subject and produces injurious affective relationships. In this way, I interrogate relationships between trauma, recovery, and the everyday.

Capitalism↗

Protective effect of melatonin against fractionated irradiation-induced epiphyseal injury in a weanling rat model.

The effects of melatonin, a free-radical scavenger and a general antioxidant, on radiation-induced growth plate injury have not been studied previously. The purpose of this study was to determine the potential benefits of sparing longitudinal bone growth by fractionated radiotherapy alone compared with pretreatment with melatonin that provides differential radioprotection of normal cells. Weanling 4-wk-old (75-100 g) male Sprague-Dawley rats were randomly assigned to one of three groups: Group R received fractionated radiation alone (n = 8); groups M5 (n = 8) and M15 (n = 7) received 5 or 15 mg/kg melatonin prior to fractionated radiation, respectively. The distal femur and proximal tibia in the right leg of each animal were exposed to a therapeutic X-irradiation dose (25 Gy total in three fractions) with the contralateral left leg as the non-irradiated control. Melatonin was administered intraperitoneally to the animals 30 min before radiation exposure. Six weeks after treatment, the rats were killed and the lower limbs disarticulated, skeletonized, radiographed, and bone growth was calculated based on measurement of the bone lengths. Fractionated radiation resulted in a mean percent overall limb growth loss of 41.2 +/- 9.5 and a mean percent overall limb discrepancy of 11.2 +/- 2.2. The administration of 5 or 15 mg/kg melatonin before each of the three fractions of radiotherapy reduced the mean percent overall limb growth loss to 33.9 +/- 5.8 and 32.2 +/- 4.5, respectively, and the mean percent overall limb discrepancy to 9.4 +/- 1.6 and 8.9 +/- 1.1, respectively; these values were significantly different compared with irradiation alone (range: P = 0.01-0.04). When compared with Group R, the growth arrest recovered by 5 or 15 mg/kg melatonin was 19.7 and 24.1% for the tibia, 7 and 18.6% for the femur, and 17.7 and 21.8% for the total limb, respectively. These results support further investigation of melatonin in combination with fractionation for potential use in growing children requiring radiotherapy to the extremity for malignant tumors.

Animals↗

Palaeoanatomy and biological affinities of a Cambrian deuterostome (Stylophora).

Stylophora are a peculiar extinct group of asymmetrical deuterostomes whose biological affinity has been fiercely debated. Disarticulated skeletal elements of a ceratocystid stylophoran recovered from the earliest Middle Cambrian of Morocco are not only the oldest stylophorans in the fossil record, but their exceptional preservation provides crucial data on the microstructure of its skeleton. Stylophoran plates are constructed of a three-dimensional mesh, termed 'stereom', identical to that of living echinoderms in which stereom microstructure provides a reliable guide to the nature of the investing soft tissues. Using modern echinoderm anatomy to interpret stereom microstructure of stylophoran elements, here we show that the large proximal lumen of their appendage was filled with muscle and that ligamentary tissues bound distal elements firmly together. We find no evidence for a mouth in the proximal lumen and no evidence that the covering plates of the appendage were articulated. Thus, although skeletal structure suggests that stylophorans are echinoderms, their appendage was not a feeding arm but a muscular locomotory organ.

Animals↗

Evaluation of the vertical forces generated by the cervical biteplate facebow.

The biteplate facebow has been recommended for use in the correction of Class II malocclusions with deep overbites. This facebow is similar in design to the conventional cervical facebow with the addition of an inner bow metal plate. The plate presses against the maxillary incisors and prevents the patient from fully closing, thus acting as a biteplate. A test apparatus was constructed to simulate the force system present during application of the facebow. In this study, high resolution force transducers were used to measure the intrusive forces on the maxillary and mandibular incisors. Static force analysis techniques were then used to calculate the vertical force component of the first molars. Analyses were performed using a wide range of relative bow angles, neck strap tensions of 200 grams and 400 grams, and various mandibular incisor occluding forces. The molar eruptive forces of the biteplate facebow are found to exceed those of the standard cervical facebow by a low of 158% to a high of 537%, depending on the neck strap tension and the inner bow/outer bow angle. While the intrusive forces on the maxillary incisors were excessive, no intrusion is anticipated because the biteplate disarticulates the posterior teeth and the eruption of the unopposed maxillary molars would likely cause the occlusal plane to tip in a counter-clockwise direction. Consequently, the overbite correction would be obtained through maxillary molar eruption accompanied by occlusal plane tipping. Before considering use of the biteplate facebow, a patient's anticipated growth pattern, the magnitude of the intrusive forces and the treatment objectives should be evaluated.

Activator Appliances↗

Immune tolerance in a haemophilia A patient with high inhibitor using locally prepared lyophilized cryoprecipitate.

The immune tolerance in a 12-year-old haemophilia A patient was carried out at the Faculty of Medicine, Ramathibodi Hospital, Bangkok in 1998. His inhibitor titres ranged from 10 to 3450 Bethesda units (BU). He suffered from serious bleeding episodes requiring prolonged hospitalization and the disarticulation of the left knee joint. After obtaining informed consent, locally prepared lyophilized cryoprecipitate (LC), heat treated at 60 degrees C for 25 h, was given in a dose of 13 units kg-1 body weight of factor VIII three times per week. His inhibitor was increased from 15 to 580 BU within the first 4 weeks of immune tolerance. Finally, it was decreased to 40 BU in the 36th week. The only adverse effect was seroconversion of anti-hepatitis C virus after receiving 108 bottles of LC for 36 weeks. In conclusion, the locally prepared LC was able to control the bleeding episodes in a haemophilia A patient with high inhibitor. To our knowledge, this is the first reported case in Thailand.

Chemical Precipitation↗

The surface contour of articular cartilage in an intact, loaded joint.

The friction coefficients measured in diarthrodial joints are small. Theories of joint lubrication attribute this efficiency to entrapment or movement of synovial fluid, yet anatomical models of the surface are based on studies of isolated fragments of cartilage, not functional joints. To investigate the functional interrelationship of joint surfaces and synovial fluid, the ultrastructure of loaded joints was examined. Twenty-four New Zealand white rabbit knee joints were loaded either statically or moved ex vivo using simulated muscle forces and then plunge-frozen under load. After fixation in the frozen/loaded state by freeze-substitution fixation, the medial joint compartments were embedded in epoxy resin while still articulated. Bone was trimmed away from the articular surfaces, permitting the cartilage to be sectioned for light and electron microscopy. These joint surfaces were then compared with controls which were not loaded, not moved or had been disarticulated prior to embedding. Articular surfaces of loaded joints were smooth at magnifications from x 35 to x 7500, whereas the tibial surfaces of nonloaded joints were irregular. Small pools of joint fluid were observed at the meniscal edge and beneath the anterior horn of the meniscus. At magnifications of x 40000, the joint surfaces were separated by a uniform 100 nm space containing fluid. An amorphous, electron dense articular surface lamina was present but, when loaded, was thicker and flatter than previously reported. No surface pits or bumps were visible in embedded, loaded joints. This is the first ultrastructural study of intact loaded joints. The findings suggest that fluid film lubrication is present in diarthrodial joints, but the fluid sequestration postulated in several models is not apparent.

Animals↗

Limb salvage by neoadjuvant isolated perfusion with TNFalpha and melphalan for non-resectable soft tissue sarcoma of the extremities.

AIMS: Patients with non-resectable soft tissue sarcomas of the extremities do not live longer if they are treated by amputation or disarticulation. In order to avoid major amputations, we tested isolated limb perfusion (ILP) with tumour necrosis factor alpha (TNF)+melphalan+/-interferon-gamma (IFN) as a pre-operative, neoadjuvant limb salvage treatment. METHODS: Twenty-two patients were included (six men and 16 women; three upper limb and 19 lower limb tumours). The AJCC stage was IIA in four patients, III in seven and IV in 11. Thirteen cases were recurrent or progressive after previous therapy; five tumours had a diameter >/=20 cm, and four were multiple or regionally metastatic. There were six malignant fibrous histiocytomas, five liposarcomas, four malignant peripheral nerve sheath tumours, three rhabdomyosarcomas, two leiomyosarcomas, one recurrent extraskeletal osteosarcoma and one angiosarcoma. RESULTS: Twenty-four ILPs were performed in the 22 patients, and 18 (82%) experienced an objective response: this was complete in four (18%) and partial in 14 (64%). Three patients had a minimal or no response and the tumour progressed in one case. All patients had fever for 24 hours but only one developed a reversible grade 3 distributive shock syndrome with no sequelae. There was no grade 4 toxicity. Seventeen patients (77%) underwent limb-sparing resection of the tumour remnants after a median time of 3.4 months: 10 resections were intracompartmental and seven extracompartmental. Surgery included flaps or skin grafts in five patients, arterial replacement in two and knee arthrodesis in one. Adjuvant chemotherapy was given to eight patients and radiotherapy to six. In one patient amputation was necessary after a second ILP. Secondary amputations were performed for recurrence in two patients, resulting in an overall limb salvage rate of 19/22 (86%). After a median follow-up of 18.7 months, 10 recurrences were recorded: seven were both local and systemic and three were only local. The median disease free and overall survival times have been >12.5 and 18.7 months respectively: this is similar to the outcome after primary amputations for similar cases. CONCLUSION: ILP with TNF and chemotherapy is an efficient limb sparing neoadjuvant therapy for a priori non-resectable limb soft tissue sarcomas.

Adult↗