Afferent innervation of outer and inner hair cells is normal in neonatally de-efferented cats

It has been hypothesized that normal pruning of exuberant branching of afferent neurons in the developing cochlea is caused by the arrival of the olivocochlear efferent neurons and the resulting competition for synaptic sites on hair cells. This hypothesis was supported by a report that afferent innervation density on mature outer hair cells (OHCs) is elevated in animals deefferented at birth, before the olivocochlear system reaches the outer hair cell area (Pujol and Carlier [1982] Dev. Brain Res. 3:151-154). In the current study, this claim was evaluated quantitatively at the electron microscopic level in four cats that were de-efferented at birth and allowed to survive for 6-11 months. A semiserial section analysis of 156 OHCs from de-efferented and normal ears showed that, although de-efferentation essentially was complete in all four cases, the number and distribution of afferent terminals on OHCs was indistinguishable from normal, and the morphology of afferent synapses was normal in both the inner hair cell area and the OHC area. Thus, the postnatal presence of an efferent system is not required for the normal development of cochlear afferent innervation, and the synaptic competition hypothesis is not supported.     

The three-in-one proximal and distal soft tissue patellar realignment procedure. Results, and its place in the management of patellofemoral instability.

The three-in-one procedure for extensor mechanism realignment of the knee combines lateral release, vastus medialis obliquus muscle advancement, and transfer of the medial one-third of the patellar tendon to the tibial collateral ligament. We observed 37 patients (42 knees) receiving this treatment at a minimum 25-month follow-up (range, 25 to 85 months; mean, 44). Thirty-two of 42 knees (76%) with recurrent patellar dislocation had good or excellent results after surgery. Redislocation occurred in four knees (9.5%). Skeletal immaturity, chondral damage, and generalized ligament laxity did not seem to affect outcome. Thirty patients (37 knees) were studied 2 years earlier as well (mean follow-up, 29 months). When comparing the results 2 years later, there was a significant deterioration in outcome over time. These results are comparable with the published results for other techniques of patellar stabilization. We describe the place of the three-in-one operation in our surgical protocol for patellofemoral instability, which is based on the principle that a procedure should be selected to address the underlying pathologic features in an individual case rather than always using one operation for all cases.     

Identification and initial characterization of 5000 expressed sequenced tags (ESTs) each from adult human normal and osteoarthritic cartilage cDNA libraries

OBJECTIVE: To prepare, sequence and analyse adult human cartilage cDNA libraries to study the gene expression pattern between normal and osteoarthritic cartilage. METHODS: Poly A(+)RNA from adult human normal and osteoarthritic articular cartilage was isolated and used to prepare cDNA libraries. Approximately 5000 ESTs from each library were sequenced and analysed using bioinformatic tools. The expression of select genes was confirmed by Northern blot and in situ hybridization analysis. RESULTS: Multiple gene families including several classical cartilage matrix protein encoding genes were identified. Approximately 28-40% of the genes sequenced from these libraries were novel, while half of the genes encoded known proteins and 4-6% of the genes encoded novel homologs of known proteins. Several known genes, whose expression has not been reported previously in cartilage, were also identified. We have confirmed the cartilage expression of three known (CTGF, CTGF-L and clusterin) and two novel homologs of known genes (PCPE-2 and Gal-Nac transferase) by Northern blot and in situ hybridization analysis. CONCLUSION: This is the first report of the preparation and sequencing of cDNA libraries from adult human normal and osteoarthritic articular cartilage. Further analysis of genes identified from these libraries may provide molecular targets for diagnosis and/or treatment of osteoarthritis (OA).     

Simultaneous bilateral total knee arthroplasties: who decides?

The purpose of the current retrospective review was to compare the results of 1498 patients having 1090 simultaneous bilateral total knee arthroplasties and 958 unilateral total knee arthroplasties in a 3-year period, focusing on perioperative complications, length of hospital stay, and discharge disposition. Gender, age, diagnosis, and weight were similar between the groups. Patients undergoing simultaneous bilateral total knee arthroplasties had statistically significant higher amounts of intraoperative blood loss, with more patients requiring blood transfusion, and a higher average number of units of blood transfused compared with patients undergoing unilateral total knee arthroplasty. Overall, a significantly higher incidence of gastrointestinal complications was reported in patients who had simultaneous bilateral knee arthroplasties compared with patients who had unilateral knee arthroplasty. Comparing age subgroups within the unilateral group revealed significantly higher incidences of pulmonary, neurologic, cardiac, and genitourinary complications among patients 80 years or older versus patients younger than 80 years. Patients having simultaneous bilateral arthroplasties who were 80 years or older had significantly higher incidences of pulmonary, neurologic, and cardiac complications than patients younger than 80 years in that same group. These results suggest that age, not procedure, has a more significant role in the perioperative morbidity of total knee arthroplasty. Based on the results from the current study and previous literature documenting patient preference, patient satisfaction, efficacy, and outcomes comparable with those of patients having unilateral total knee arthroplasty, the authors continue to offer patients the option of simultaneous bilateral total knee arthroplasties.     

Altered Cro repressors from engineered mutagenesis of a synthetic cro gene.

A portion of the gene coding for the Cro repressor protein of bacteriophage lambda has been chemically synthesized, incorporating base pair changes that generate restriction endonuclease sites without altering the amino acid coding sequence. These restriction endonuclease sites were used to remove small segments of the synthetic cro gene and the segments were replaced with duplexes carrying desired mutations. Altered Cro proteins produced by mutants constructed in this manner were then assayed for binding to lambda operator OR3 in vivo. Mutations directed into the region of the cro gene encoding the alpha-3 helix produced altered Cro proteins with a range of affinities for operator DNA. These changes suggest which amino acids play an important role in Cro-OR3 complex formation.     

Cognitive dysfunction after minor surgery in the elderly

BACKGROUND: Major surgery is frequently associated with postoperative cognitive dysfunction (POCD) in elderly patients. Type of surgery and hospitalization may be important prognostic factors. The aims of the study were to find the incidence and risk factors for POCD in elderly patients undergoing minor surgery. METHODS: We enrolled 372 patients aged greater than 60 years scheduled for minor surgery under general anesthesia. According to local practice, patients were allocated to either in- (199) or out-patient (173) care. Cognitive function was assessed using neuropsychological testing preoperatively and 7 days and 3 months postoperatively. Postoperative cognitive dysfunction was defined using Z-score analysis. RESULTS: At 7 days, the incidence (confidence interval) of POCD in patients undergoing minor surgery was 6.8% (4.3-10.1). At 3 months the incidence of POCD was 6.6% (4.1-10.0). Logistic regression analysis identified the following significant risk factors: age greater than 70 years (odds ratio [OR]: 3.8 [1.7-8.7], P = 0.01) and in- vs. out-patient surgery (OR: 2.8 [1.2-6.3], P = 0.04). CONCLUSIONS: Our finding of less cognitive dysfunction in the first postoperative week in elderly patients undergoing minor surgery on an out-patient basis supports a strategy of avoiding hospitalization of older patients when possible.     

Human hair follicle dermal sheath and papilla cells support keratinocyte growth in monolayer coculture

Traditional skin grafting techniques are effective but limited methods of skin replacement. Autologous transplantation of rapidly cultured keratinocytes is successful for epidermal regeneration, but the current gold‐standard technique requires mouse fibroblast feeders and serum‐rich media, with serum‐free systems and dermal fibroblast (DF) feeders performing relatively poorly. Here, we investigated the capacity of human hair follicle dermal cells to act as alternative supports for keratinocyte growth. Dermal papilla (DP) dermal sheath (DS), DF and 3T3 cells were used as inactivated feeder cells for human keratinocyte coculture. Under conditions favouring dermal cells, proliferation of keratinocytes in the presence of either DS or DP cells was significantly enhanced compared with DF cells, at levels comparable to keratinocytes cultured under gold‐standard conditions. Secreted protein acidic and rich in cysteine (SPARC) expression increased DS and DP cells relative to DFs; however, further experiments did not demonstrate a role in keratinocyte support.     

Renal response to restricted protein intake in diabetic nephropathy

Proteinuria in diabetes is associated with progressive glomerular damage. We studied the effects of 3-wk dietary protein restriction on proteinuria and renal function in 10 insulin-dependent diabetic men with diabetic nephropathy. Patients were randomly assigned by a crossover design to 40-g low-protein diet (LPD) or usual-protein diet (UPD). Glomerular filtration rate and renal plasma flow were measured by inulin and p-aminohippurate clearance at the end of each period under conditions of sustained euglycemia. Total calorie intake, body weight, serum albumin and total protein concentrations, hematocrit, blood pressure, and glucose control were similar during the two diets. Achieved protein intake was 46 +/- 3 g/day during LPD and 81 +/- 4 g/day during UPD (P less than .001). Urinary urea appearance and plasma urea were significantly lower on LPD. Median total urinary protein was reduced from 3.9 g/day (range 0.5-12.3) on UPD to 2.4 (range 0.2-9.0) on LPD (P less than .006), and there was a significant fall in the median fractional clearance of albumin from 2.0 x 10(-4) (range 0.1-90.9) on UPD to 1.0 x 10(-4) (range 0.1-51.4) on LPD and IgG from 2.1 x 10(-5) (range 0.2-238) to 1.5 x 10(-5) (range 0.1-77) (P less than .006 and P less than .02, respectively). The reabsorption rate of beta 2-microglobulin was similar on the two diets and glomerular filtration rate, renal plasma flow, and filtration fraction remained unchanged. Thus, short-term dietary protein restriction reduces diabetic proteinuria independently of blood glucose or systemic blood pressure changes by improving glomerular permselectivity.     

Malignant oncocytoma of the maxillary sinus— An ultrastructural study

A unique case of a malignant oncocytoma of the maxillary sinus is reviewed in detail. The ultrastructural findings are presented. The histologic and ultrastructural criteria that characterize onco-cytes and the clinicopathologic features of benign and malignant oncocytomas are discussed. This case represents the eleventh reported case that would truly qualify as a malignant oncocytoma of the paranasal sinuses.