Dynamic response of human cervical spine ligaments

This study was undertaken to investigate the dynamic response of human cervical spine ligaments. Uniaxial tensile failure tests were conducted on anterior longitudinal ligament (AL) and ligamentum flavum (LF) structures. These ligaments were tested under in situ conditions by transecting all the elements except the one (AL or LF) under study. A fixture was designed to properly align the specimen to induce a uniaxial mode of loading. A six-axis load cell was placed at the distal end of the specimen. The proximal end of the specimen was attached to the piston of a specially designed electrohydraulic testing device. The biomechanical properties of the ligaments were determined at four different loading rates of 8.89, 25.0, 250.0 and 2500 mm/sec. The mechanical response indicated nonlinear and sigmoidal characteristics. The ultimate tensile failure load, stiffness, and energy-absorbing capacity at failure were found to increase with increasing loading rates for both the AL and LF. However, the distractions at failure did not indicate this tendency. While the ultimate tensile force and ultimate energy-absorbing capacity varied nonlinearly with the logarithm of the loading rate, the stiffness varied linearly.     

Malignant carcinoid of the stomach and distal esophagus

Summary and conclusions The first case of a gastric carcinoid involving the distal esophagus is reported, with a brief summary of reviewed literature of gastric carcinoids. Emphasis should be made of the relatively benign nature of this malignant condition and, therefore, an aggressive surgical approach should be carried out.     

Urine cytology findings in analgesic nephropathy

Urine cytology screening for neoplasm led to the detection of 3 urothelial carcinomas and 1 severe urothelial dysplasia in 98 patients with analgesic-induced papillary necrosis. A further 18 patients had changes suggesting that they were at risk of incurring malignancy in the near future. Routine urine cytology is recommended in all cases of analgesic nephropathy.     

Effects of cadmium, copper, and zinc on βAPP processing and turnover in COS-7 and PC12 cells

The effects of cadmium, copper, and zinc on βAPP metabolism were investigated in COS-7 and PC12 cells. Cadmium chloride (CdCl₂) increased βAPP steady-state protein levels and decreased βAPP posttranslational processing. These changes were not accompanied by alterations in βAPP mRNA levels or splicing. In addition, cytosolic α-actin and G3PDH levels were not affected. Further, neither zinc (ZnCl₂) nor copper (CuSO₄) altered βAPP levels or affected its normal processing. Pulse-chase studies revealed that the rate of βAPP maturation decreased twofold in the presence of 25 μM CdCl₂ compared to untreated controls. βAPP secretion from the cell also dramatically slowed. These two factors result in the accumulation of partially processed βAPP inside cells. The presence of CdCl₂ also decreased the amount of an 8-kDa βAPP C-terminal fragment, indicating that the cellular compartment in which βAPP accumulates is not accessible to α-secretase. Studies using Brefeldin A suggest that this compartment may be thecis ormedial Golgi. However, Aβ production was proportionately increased. These data show that CdCl₂ can modulate the βAPP cleavage to favor Aβ. Finally, βAPPmis-metabolism was shown to be unrelated to the hsp70 induction elicited by CdCl₂; both heat shock and CuSO₄ induced hsp70 but had no effect on steady-state levels of βAPP, although heat shock did slow βAPP maturation. These data indicate that hsp70 alone cannot chaperone βAPP through an alternate processing pathway leading to Aβ production.     

The fate of the skin graft in laryngoplasty

In laryngoplasty procedures, laryngotracheal soft tissue defects are often repaired using skin grafts. While stenting is necessary to approximate and immobilize the graft, prolonged stenting causes increased bacterial counts, granulation tissue formation, tissue ischemia, and graft failure. Optimal time for stent removal has not been experimentally defined. Using the ferret animal model, 24 laryngoplasty procedures were performed. The subjects were stented by group for 0, 3, 7, 14, or 28 days. Analysis consisted of quantitative bacteriology, dye perfusion, and quantitative histologic assessment of graft viability. Tissue culture results revealed that by 3 days after the procedure all groups had 10⁵ CFU of bacteria per gram of tissue. Graft viability in successful procedures was maximal in the 7-day group and statistically significant from the 3-day to the 28-day groups. In conclusion, while stenting is necessary for graft adherence, prolonged exposure to local tissue sepsis leads to progressive graft destruction.     

Lumbar herniation of the kidney

We report a case of lumbar herniation of a kidney, resulting in intermittent ureteropelvic junction obstruction. Surgical repair of the lumbodorsal fascial defect resulted in resolution of the uretero-pelvic junction obstruction.     

Supratentorial tumours in infants

Three hundred and ninetysix paediatric (below 15 years of age) patients with brain tumours were treated at our institute in the last 4 years. Eighty-two of the tumours were located supratentorially. These 82 patients included 14 infants (below 1 year of age), who made up 3.5% of all paediatric patients with brain tumours and 17% of those with brain tumours in a supratentorial location. There was a male preponderance, and two-thirds of the 14 patients were within their first 6 months of life. Increasing head size, vomiting and failure to thrive were the common presenting features. One infant presented with asymmetric skull growth. The tumours tended to be large, occupying almost the entire affected cerebral hemisphere; histological types included astrocytomas, malignant astrocytomas, glioblastoma multiforme, primitive neuroectodermal tumours, malignant choroid plexus papillomas and malignant teratomas. Two children had congenital tumours and another two tumours, in children with associated lobar agenesis, were thought to be congenital in origin. Associated hydrocephalus was present in seven patients, but precraniotomy shunt was required in only two patients. The perioperative (within 1 month) mortality was 57%. Only 30% of the patients survived for more than 1 year after surgery and chemotherapy. The longest survival was 20 months. Delay in diagnosis, poor general condition prior to surgery, and the high vascularity and malignant nature of these tumours accounted for the poor results.